Wikipedia:Reference desk/Archives/Science/2017 August 30

= August 30 =

Today's featured picture of moss
In today's featured picture of moss, the green chloroplasts appear to be within an otherwise green cell. Is that because the photo is capturing green coloration from the chloroplasts of many layers of cells deep to the superficial layer? Or are there chlorophyll particles also within the plant cell cytoplasm.  DRosenbach  ( Talk 00:54, 30 August 2017 (UTC)
 * The image I have added seems to show chloroplasts at least two organelles deep in places, with the ones in back out of focus, making it appear to have a green background. And chlorophyll is not so much a particle as a pigment molecule with a very definite structure embedded in a complex matrix. μηδείς
 * (talk) 01:05, 30 August 2017 (UTC)


 * I found this interesting paper which says clearly that "every chlorophyll molecule is synthesized in the chloroplast from eight molecules of 5-aminolevulinic acid" In fact, even the 5-aminolevulinic acid is rigged to be produced only in the chloroplast of higher plants, because glutamate must first be ligated to the chloroplast gene for tRNAGlu, which is the substrate for the reaction!  Note however that this isn't the sole explanation for the localization, since the tRNAGlu should be in the stroma of the chloroplast, which is between the inner chloroplast membrane and the thylakoid membrane, but according to  electron transport chains are absent from the inner chloroplast membrane.  Proteins have a role in keeping chlorophyll where it is supposed to be and they can be targeted there, but I don't really know that's the reason.  I would anticipate something as flat and hydrophobic looking as chlorophyll would tend to stay put in a membrane once targeted, but I don't know that for sure either. Wnt (talk) 22:36, 30 August 2017 (UTC)


 * It wasn't my intention to go into a long explanation at a highly technical level, but to answer the OP. Basically you can think of chlorophyll as a somewhat large, complex pigment molecule that captures a photon, uses the photon to excite an electron to fuel a very complex electrochemical process, and which is thus like an electronic part that has to be in the right place and with the right connections to work properly. The OP can read the relevant articles which were already linked to above.  It's not something like sugar that you can dissolve and let float about freely in water to make a sweet drink. It's more like a gear in a watch that will stop the watch from working if it is displaced or damaged. μηδείς (talk) 04:23, 31 August 2017 (UTC)
 * Well, I'm still not all that confident about the details. For example, cytochrome c famously has a totally different role outside the mitochondrion.  For all I know chloroplasts could release some kind of "exovesicle" within the cell, though I know of no precedent for that.  (wow - Wikipedia does not mention the word - there's some fun editing to be done...)  My feeling is that high-level explanations really aren't that reliable in biology; unless you find someone who has carefully studied the distribution of chlorophyll in this kind of moss, it still isn't certain. Wnt (talk) 16:09, 1 September 2017 (UTC)


 * Cytochrome C is not chlorophyll. Your pseudoscience needs an ypgræde. μηδείς (talk) 21:41, 1 September 2017 (UTC)


 * Your reaction confuses me. I was simply illustrating that a polypyrrole containing protein can be released from a symbiotic organelle.  Looking just a little deeper, this points at a review about the phototoxicity of free chlorophyll in the cell (understandably enough, it has a tendency to release uncontrolled energy when out of a complex).  However, there are water-soluble chlorophyll-binding proteins that can scavenge free chlorophyll and protect the cell from damage.
 * Also, no matter how lovely the picture, we have to bear in mind that this is still not a living leaf in the wild we are looking at, but a specimen in which cells may be damaged or dying due to how they have been prepared. So we cannot assume that the level of free chlorophyll at the moment the image was taken is representative or survivable. Wnt (talk) 09:32, 2 September 2017 (UTC)
 * Well, yes, when I took Biochemistry as a 14 year-old, the head of the Biology Department at Rutgers (Camden) did show that one could temporarily remove chlorophyll from chloroplasts and have it remain bioactive. But moss doesn't have leaves, either, but "bracts".  So what should I tell you about your personal ignorance of the subject?  This bores me. μηδείς (talk) 22:23, 2 September 2017 (UTC)

chess and reasoning power
Does playing chess require much reasoning power? — Preceding unsigned comment added by Uncle dan is home (talk • contribs) 03:28, 30 August 2017 (UTC)
 * No, though it helps if one doesn't want to lose constantly. Ian.thomson (talk) 03:31, 30 August 2017 (UTC)

See here: "In a November 2006 match between Deep Fritz and world chess champion Vladimir Kramnik, the program ran on a personal computer containing two Intel Core 2 Duo CPUs, capable of evaluating only 8 million positions per second, but searching to an average depth of 17 to 18 plies in the middlegame thanks to heuristics; it won 4–2." And note that a laptop is not powerful enough to simulate the brain of a spider in real time. Count Iblis (talk) 03:57, 30 August 2017 (UTC)


 * I, for one, wish to welcome our new spider overlords.... μηδείς (talk) 04:02, 30 August 2017 (UTC)
 * You may therefore enjoy Adrian Tchaikovsky's novel Children of Time. {The poster formerly known as 87.81.230.195} 90.204.180.96 (talk) 10:28, 31 August 2017 (UTC)
 * It doesn't need much reasoning power to be able to play a legal game of chess. It needs significantly more, however, to play well. Of course reasoning power is not all of it, too; you need strong pattern recognition as well, for one. Mind you, I would consider the spider comparison of Count Iblis rather irrelevant, because chess programs are in essence one-trick ponies, which living organisms obviously are not. And while humans do lose to top computers, I have to wonder how much of it is due to the fact that humans get tired and blunder on occasion, as famously happened during the particular match he cites. Double sharp (talk) 04:53, 30 August 2017 (UTC)
 * See Chess for a description of the reasoning required in chess. Blooteuth (talk) 09:30, 30 August 2017 (UTC)
 * Even if Kasparov had his entire lifetime to play his match against Deep Blue, I still don't think he would have won. Computers are able to objectively quantify the many many options in a game of chess much better than humans. shoy (reactions) 14:39, 31 August 2017 (UTC)
 * He almost certainly could have IMHO, especially given that he won in 1996. The score was even before the sixth game and I suspect Kasparov played 7...h6? purely because he felt that computers of that time would not be able to see the compensation after 8.Nxe6! (which he knew of) and would handle the position incorrectly – which was mostly true, but Deep Blue happened to have the line in its book and be good enough to play it. Had he not tried anti-computer tactics, and instead played the position rather than the opponent, he would likely have played the normal 7...Bd6. And while a lot of typical amazing computer moves look impossible to see for humans, that is not true either: see entries 296 and 297 of Tim Krabbé's open chess diary, for example. Double sharp (talk) 05:24, 1 September 2017 (UTC)

Tamping/ramming tool
Hello all, I'm about to put my pilot plant into operation, but there's one thing I still need -- a sturdy tamping/ramming tool, with its business end at least 1 inch but no more than 1.25 inches in diameter, and with a handle at least 2 feet long (for repacking the catalyst bed). The problem is, I don't know the correct name for such a tool, much less where to find one. Thanks in advance! 2601:646:8E01:7E0B:84FD:477A:71AB:7A1E (talk) 05:10, 30 August 2017 (UTC)


 * It sounds like you're describing a 1" diameter metal rod. Something like this: https://www.onlinemetals.com/merchant.cfm?pid=15291&step=4&showunits=inches&id=1114&top_cat=60 obviously can be had in other metals if aluminum is a problem.2602:306:CF32:13A0:9C44:6B42:8646:43CF (talk) 05:32, 30 August 2017 (UTC)
 * I don't think they make espresso tampers that small (I've seen 49mm and maybe they go a little smaller) but if you do a web search, it might give you some ideas. 173.228.123.121 (talk) 07:23, 30 August 2017 (UTC)
 * The name of the tool is a tamp or tamper, see Tamp. Blooteuth (talk) 09:16, 30 August 2017 (UTC)
 * It sounded like a cannon to me! Those ones are called ramrods. Dmcq (talk) 11:02, 30 August 2017 (UTC)
 * Thanks! 2601:646:8E01:7E0B:4DFA:5B5D:E0B4:4FDF (talk) 10:08, 2 September 2017 (UTC)

hurricane water
The first thing that comes to mind about hurricanes is enormous amounts of water falling out of the sky, causing flooding, etc. If that water is essentially rain (i.e. condensed from vapor) it should be relatively pure and drinkable, right? And in that case, why are people sending bottled water to Texas? Or is the hurricane water actually mostly sea water sucked up into the cyclone over the ocean and then dropped onto land? And if it's that, does it mean that any agriculture areas it fell on are now salted? Thanks. 173.228.123.121 (talk) 07:28, 30 August 2017 (UTC)


 * "Hurricane water" over land is mostly rain (on a ship at sea level, spray may play an important role). But rainwater isn't necessarily pure nowadays (it goes through the atmosphere, which is full of crap we release into it - see e.g. acid rain), and most people are not prepared to safely catch and use rainwater. Moreover, even if rain water is pure enough for drinking immediately, it is very hard to avoid contamination, which could lead to bacterial growth and disease quickly. Even if these risks are low at a personal level, they are significant from an epidemiological point of view. Remember - there are nearly 7 million people in the Houston Metropolitan Area. If only 1% of them catch a water-borne disease, and 1% of these die, the death toll will be 700 - or about 20 times the current estimate. --Stephan Schulz (talk) 08:20, 30 August 2017 (UTC)


 * In any flood, pretty much the first thing that happens is the sewers become overloaded and spill out. Flood water is contaminated with all kinds of nasties - human waste, animal manure, fertilizer, rotten food (our article Social effects of Hurricane Katrina mentions that one problem was that raw chicken and shrimp got washed into the water table, leading to E coli outbreaks). Collecting rainwater and keeping it pure is difficult at the best of times (see water butt for some of the challenges), and I don't know how you could collect enough drinking water for a family in the middle of a storm. Smurrayinchester 09:40, 30 August 2017 (UTC)


 * I'm not sure that most of the water is fresh - see storm surge. At the very least it will be brackish. Matt Deres (talk) 13:47, 30 August 2017 (UTC)
 * Well, that is not "water falling out of the sky", and it's not the water that is currently flooding Houston. Storm surge is a different effect that may cause problems near the coast. --Stephan Schulz (talk) 20:19, 30 August 2017 (UTC)


 * Can see where the OP is coming from. The rain itself may be drinkable but the flood water is not homogeneous rain water. Stuck in such a situation one might just take a mouthful of an infectious dose. Personally, I think the bottled water being distibuted, should be further sanitized with 50/50 dose of a either Mezcal, Tequila or bourbon. But that is just my opinion. Yet, I think that there are many hundreds of wet people just now, that would agree with me. Donald – are you listening? Aspro (talk) 15:54, 30 August 2017 (UTC)


 * As for setting up a rainwater collection area (basically a funnel leading to a tank), there are 3 possible situations:


 * During the worst part of hurricane, collection is not possible, as winds would knock it all down.


 * Before and after the worst part, collection might be possible. However, the rainwater collected before would need to be moved some place safe so it doesn't get knocked down during the hurricane.


 * After it's all over, there may not be any rain at all.


 * So, there may be some windows where collection is possible, but people may be too busy trying to make other preparations before or search for survivors after to collect rainwater. Some type of automated system that's battery powered and can deploy and retract the funnel based on wind speed and rain would be ideal.  Any collection apparatus would need to be high up, like on the roof, to avoid contamination from splashing ground water.


 * I wouldn't be concerned about air pollution, as any in the air initially will soon be cleaned out by the massive rainfall, and factories typically shut down well before a hurricane hits, so the amount in the air should be less for that reason, too. StuRat (talk) 16:11, 30 August 2017 (UTC)


 * What do you mean wouldn't be concerned about air pollution? There is so much contamination of H2O vapor in Hurricane Harvey that it  has been precipitating  out to such a degree, that it  affords people,  (whom are normally accustomed to one  shower per day),  to a full  24 hour bath. Talking of baths, One tale I never understood, was about two nuns in a bath and  the first one says "Where's the soap"; the second one replies "Yes it does, doesn't it" Aspro (talk) 19:07, 30 August 2017 (UTC)
 * "whom are"? --Trovatore (talk) 09:44, 31 August 2017 (UTC)
 * Oh, less importantly and by the way, they're not nuns, they're elephants, and the punch line is, "no soap, radio!". I don't get it either. --Trovatore (talk) 09:51, 31 August 2017 (UTC)
 * I always assumed it is a play on words, where's/wears. BbBrock (talk) 11:05, 1 September 2017 (UTC)


 * Cisterns of any usable size are going to collect dead birds and other animals and their droppings. There's no avoiding treatment if you don't want salmonella, psittacosis, cholera, etc.  I do my parents' gardening, and have had to remove two dead birds from their overhangs this summer. During hurricanes, waterspouts don't help. μηδείς (talk) 20:49, 30 August 2017 (UTC)

Rail and highways projects
Why do companies, whether engineering consultancies, local authorities etc, involved with transport projects separate rail and highways completely when they clearly overlap? 193.240.153.130 (talk) 08:45, 30 August 2017 (UTC)


 * Here is entertainment while we wait for an explanation. Blooteuth (talk) 10:22, 30 August 2017 (UTC)


 * Large projects must be broken up into manageable chunks, and that's one logical place to do it. StuRat (talk) 16:19, 30 August 2017 (UTC)


 * Simply because politics usually chooses that they should compete with/against eachother. --Kharon (talk) 14:16, 31 August 2017 (UTC)

Shelf life of computer science books
Moved to Reference_desk/Computing--B8-tome (talk) 17:59, 30 August 2017 (UTC)

drag coefficient and lift coefficient
I'd like to know the values of these coefficients, say, for cessna 172, when it's on the runway towards liftoff ? Of course, these values depend on the angle of attack, namely, it's required 1st to know this angle while running. I hope there's a pilot or an aeronautical engineer in the audience. Thanks, בנצי (talk) 19:33, 30 August 2017 (UTC)

Toyota alphard - first generation
Where is the battery and how does one access it? Kittybrewster  &#9742;  21:31, 30 August 2017 (UTC)
 * First be clear whether your Toyota Alphard (see article) is a gasoline-only or hybrid model. The gasoline-only models are 2.4 L 160hp and 3.0 L 220hp and have a 12V starter battery at the front shown here. The hybrid model I assume follows the pattern that Toyota established with their Prius model, see Toyota_Prius. It has 2 batteries. 1) A 12V lead-acid battery that is relatively small since it has only low current demands; in the Prius this battery lives under the floor at the rear right corner of the car and is practical for a user to replace. 2) The traction battery pack is a large unit under the rear seat. Accessing this battery requires tools and precautions against dangerous high voltages that should be entrusted to a workshop. This video shows installation of a Prius traction battery. Blooteuth (talk) 22:19, 30 August 2017 (UTC)