Wikipedia:Reference desk/Archives/Science/2012 April 28

= April 28 =

The new "Xi_b^*" baryon
Is http://www.sciencedaily.com/releases/2012/04/120427095621.htm trying to write "$$\Xi_b^*$$"? Whose fault was it that the TeX got put into a press release?

More importantly, what will the Wikipedia article on the new particle be named? 70.58.10.111 (talk) 04:24, 28 April 2012 (UTC)
 * See Xi baryon for more information and further reading on this class of particles. -- Jayron  32  04:49, 28 April 2012 (UTC)


 * The new particle is not yet included in our article. The quark content of the new particle is said to be up/strange/bottom.  With the naming convention described in our article, this should be called $$\Xi_b^0$$, but this is already a known particle.  I don't know what the asterix is supposed to indicate, high energy unstable state perhaps?  Spinning  Spark  11:18, 28 April 2012 (UTC)
 * To quote the original reference's abstract (1204.5955v1), "the $$\Xi_b^{*0}$$ baryon, the JP = 3/2+ excitation of the $$\Xi_b^0$$." DMacks (talk) 16:56, 28 April 2012 (UTC)

What is this black substance ?
http://img804.imageshack.us/img804/7756/image1os.jpg and http://img4.imageshack.us/img4/9763/size2k.jpg what is black substance in these photos ? — Preceding unsigned comment added by 182.185.194.68 (talk) 10:44, 28 April 2012 (UTC)
 * I'm guessing from context that it's cannabis resin, but these photos are awful, and you need to give us better context. AlexTiefling (talk) 11:08, 28 April 2012 (UTC)
 * I can't convince myself the black object in the first picture is the same as the brown one in the second. The first one looks like it might be wrapped in black plastic - maybe the pictures didn't specify it was unwrapped between shots?  From context I'm thinking the second one is a brownie, but that's just my stomach talking. ;) Wnt (talk) 13:05, 28 April 2012 (UTC)
 * I think you are right these seems to be two separate objects. I have added more images, http://imm.io/nvhd, http://imm.io/nvj3, http://imm.io/nvk7, http://imm.io/nvkV, http://imm.io/nvlG, http://imm.io/nvoM, http://imm.io/nvpx, http://imm.io/nvpU, http://imm.io/nvqu. Some have been cropped and some are in original size. Hopefully these will be of help. — Preceding unsigned comment added by 182.185.194.68 (talk) 14:35, 28 April 2012 (UTC)
 * I don't know if any of these things is the same as any other. There are certainly more than two or three different objects.  There might be a second one of the same "brownie" as the second original image .  I still keep picturing brownies, also brownie batter  - if these pictures are from a medical marijuana user I'd believe it, since many of them prefer to avoid smoking for health reasons. Wnt (talk) 16:45, 28 April 2012 (UTC)
 * Never heard of hash brownies? --TammyMoet (talk) 17:30, 28 April 2012 (UTC)
 * Well this is certainly not marijuana for medical use, as too many cigarettes can be seen in the photos. Can it be Charas, where taken in Pakistan. — Preceding unsigned comment added by 182.185.194.68 (talk) 19:37, 28 April 2012 (UTC)
 * Sure, it could be. It could also be many other things. These photos are not enough for a positive identification of any sort. Perhaps if you could touch it, smell it, taste it, or burn it, you could narrow down the possibilities. Charas should behave rather differently than e.g pitch under a few of these basic tests. 96.235.227.66 (talk) 00:50, 29 April 2012 (UTC)
 * Presence of Joint (cannabis) confirm marijuana smoking, is charas quite plastic ? I mean it's shape can easily changed ?  — Preceding unsigned comment added by 182.185.194.68 (talk) 01:59, 29 April 2012 (UTC)

Freezing
Why does hot water freeze faster than cold water? --108.206.4.199 (talk) 13:54, 28 April 2012 (UTC)


 * Mpemba effect has some explanations - which pertain depends on the specific experimental setup. -- Finlay McWalterჷTalk 14:01, 28 April 2012 (UTC)


 * ... and, of course, the statement, as given, is false in many circumstances.   D b f i r s   15:36, 28 April 2012 (UTC)
 * As with several other of the OP's ref desk questions. ←Baseball Bugs What's up, Doc? carrots→ 18:10, 29 April 2012 (UTC)

This is User:Tango's favorite subject. :) Count Iblis (talk) 15:38, 28 April 2012 (UTC)
 * Fortunately, the photos didn't come out very well! --Tango (talk) 02:21, 29 April 2012 (UTC)

Permanent marking of stolen clothing
IMHO there is a red color, which marks stolen clothing permanently. --84.61.181.19 (talk) 17:00, 28 April 2012 (UTC)
 * Could you phrase that as a question?  Spinning Spark  17:26, 28 April 2012 (UTC)
 * Who says there is a red color, which marks stolen clothing permanently? —Tamfang (talk) 17:36, 28 April 2012 (UTC)
 * Someone with kleptomania and chromatopsia ?  Sean.hoyland  - talk 18:02, 28 April 2012 (UTC)

What is the name of the red color, which marks stolen clothing permanently? --84.61.181.19 (talk) 18:55, 28 April 2012 (UTC)


 * Dye pack, which is mostly about banks, lists Disperse Red 9 as commonly used in money packs. But I don't know about clothes. --Mr.98 (talk) 20:30, 28 April 2012 (UTC)


 * Do we truly not have an article on dye tags, as described in this HOWTO on removal of the tags (should the clerk fail to do so)? I thought that we had an article on everything. -- ToE 03:37, 29 April 2012 (UTC)
 * There are a couple article sections on the topic, but neither of them say anything about the type of ink or dye that's used: Retail loss prevention and Electronic article surveillance. Ink tag just redirects to the latter article.  Red Act (talk) 04:10, 29 April 2012 (UTC)
 * I just changed the redirect target to the former which seems more relevant.  Spinning Spark  10:13, 29 April 2012 (UTC)


 * It doesn't answer the question, but this book has a lot of interesting information. The first ink tags were made by Colour Tag and were quite vicious, using a toxic dye and a tendency to explode when removed due to being filled under pressure.  Modern versions use a non-toxic and non-flammable dye but the book does not name the chemicals. I imagine that each manufacturer has their own recipe - note that they come in a variety of colours, not just red.  Spinning  Spark  10:28, 29 April 2012 (UTC)


 * What a strangely crude device! Every retailer must have a tool to get the tags off, so any serious organized shoplifting gang must have them.  And as shown in the "howto" site it apparently isn't rocket science even for the random person to defeat them.  I haven't seen anything I recognize as similar to that in the U.S. Wnt (talk) 11:25, 29 April 2012 (UTC)
 * Sensormatic is/was another major vendor. I remember seeing various sorts of these things all over the US even within the past few years, usually looking like a large opaque off-white clothes-pin or 2-inch square. DMacks (talk) 11:43, 29 April 2012 (UTC)


 * It's not meant to be rocket science, it's meant to be a deterrent up to a certain amount of effort, and nothing more. Most shoplifting is not done by high-tech ninjas with portable (and I suppose they would have to be silent) dremels. (Anecdote: I worked at a Barnes and Noble many years ago, and we had those little RFID inventory control stickers. It wasn't actually worth the price or effort to put them into all inventory, though, so they only had us put it on things that cost more than $50, and every 10th book, or something like that. Someone, somewhere, had done the math on what the cost of the system was versus the cost in saving inventory and the deterrent value. We of course did have some "loss", but that's expected with such stores and is factored into the pricing schemes.) --Mr.98 (talk) 00:43, 30 April 2012 (UTC)

Aquifer drawdown and cloud cover.
I was about to mark a statement in the groundwater article as dubious, but then I noticed that the same statement can be found in a lot of related articles. The statement conflicts with my understanding of phase equilibrium. Here are the articles I checked:
 * Groundwater

''Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water within the hydrosphere subject to transpiration and evaporation processes, thereby causing accretion in water vapour and cloud cover, the primary absorbers of infrared radiation in the Earth's atmosphere. Adding water to the system has a forcing effect on the whole Earth system, an accurate estimate of which hydrogeological fact is yet to be quantified.''
 * Overdrafting

''Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water within the hydrosphere subject to transpiration and evaporation processes, thereby causing accretion in water vapour and cloud cover, the primary absorbers of infrared radiation in the earth's atmosphere[citation needed]. Adding water to the system has a forcing effect on the whole earth system, an accurate estimate of which hydrogeological fact is yet to be quantified.''
 * Water crisis

''Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water within the hydrosphere subject to transpiration and evaporation processes, thereby causing accretion in water vapour and cloud cover, the primary absorbers of infrared radiation in the earth's atmosphere. Adding water to the system has a forcing effect on the whole earth system, an accurate estimate of which hydrogeological fact is yet to be quantified''.
 * Water cycle

''Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water in the hydrosphere[18] that is subject to transpiration and evaporation thereby causing accretion in water vapour and cloud cover which are the primary absorbers of infrared radiation in the Earth's atmosphere. Adding water to the system has a forcing effect on the whole earth system, an accurate estimate of which hydrogeological fact is yet to be quantified.''
 * Hydrosphere

''Aquifer draw down or over drafting and the pumping of fossil water increases the total amount of water in the hydrosphere[4] that is subject to transpiration and evaporation thereby causing accretion in water vapor and cloud cover which are the primary absorbers of infrared radiation in the Earth's atmosphere. ''

I could add a dubious template to all of them, but how many more are there? And is my doubt justified? Ssscienccce (talk) 17:34, 28 April 2012 (UTC)


 * Not only dubious, but poor English. This is a pretty serious problem you've stumbled on, as it appears to be on many pages for over a year, I'm gonna see how deep the rabbit hole goes... - Running On Brains (talk) 19:15, 28 April 2012 (UTC)
 * Just another four I think, Fossil water, Drawdown (hydrology), Water table & Aquifer. Mikenorton (talk) 19:22, 28 April 2012 (UTC)
 * I was able to track it down to a single IP in February 2011, using this article as a source on some pages. Seems pretty dubious to me, but it has been postulated by some scientists (now that I actually know what the IP was TRYING to say). Still, per WP:UNDUE, it doesn't belong in most if not all of these articles, so I'm going to remove it. - Running On Brains (talk) 19:23, 28 April 2012 (UTC)
 * Just a note, I did end up leaving a sentence about sea-level rise in most of the articles, as that part is backed up by the cited study. All that stuff about extra water vapor/etc. is pure original research, and was removed. - Running On Brains (talk) 19:41, 28 April 2012 (UTC)
 * Thanks for taking the trouble :-). Ssscienccce (talk) 10:36, 30 April 2012 (UTC)

sodium metasilicate
my understanding is when sodium metasilicate comes into contact with water it becomes especially caustic kind of like calcium oxide does. My question is when it contacts with water does it react to produce a less caustic chemical kind of like calcium oxide becomes calcium hydroxide? Or does it stay as sodium metasilicate. If it does react how long does it take?--64.38.226.88 (talk) 19:38, 28 April 2012 (UTC)
 * No, sodium silicate readily dissolves into 2 Na+ + SiO3-2 and the evaporation residue will mostly be the Na2SiO3·9H2O hydrate. It's a very strong caustic base when saturated, and dangerous as such. 70.58.10.111 (talk) 01:36, 29 April 2012 (UTC)
 * Plasmic Physics (talk) 08:42, 29 April 2012 (UTC)
 * News to me. I wonder what proportion of the ion ends up as in solution? 70.58.10.111 (talk) 00:00, 1 May 2012 (UTC)
 * I would imagine a large proportion, as the equilibrium constant for the reaction of silica with water is much less than one, substituting hydroxide for water in the reaction sequence should not have a very large effect on the constant. Plasmic Physics (talk) 00:29, 1 May 2012 (UTC)
 * It would still be less than one, I guess. Plasmic Physics (talk) 00:32, 1 May 2012 (UTC)
 * I would imagine a large proportion, as the equilibrium constant for the reaction of silica with water is much less than one, substituting hydroxide for water in the reaction sequence should not have a very large effect on the constant. Plasmic Physics (talk) 00:29, 1 May 2012 (UTC)
 * It would still be less than one, I guess. Plasmic Physics (talk) 00:32, 1 May 2012 (UTC)