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March 21

Is that true that vegetables as well as eggs lose their vitamins while cooking or frying?

I was told that vegetables as well as eggs lose their vitamins while cooking or frying. The one who told me it explained me that the cooking or frying causes to the denaturation which cancel the vitamins. Is that true or just speculation? 93.126.95.68 (talk) 03:10, 21 March 2016 (UTC)

I believe it depends on the specific food, and the cooking temperature and duration involved, and which nutrient we are talking about. Some are indeed reduced by cooking, while others may be enhanced or made more readily available. And of course, some foods are dangerous to eat uncooked. Raw eggs, for example, may contain salmonella. StuRat (talk) 03:22, 21 March 2016 (UTC)

Thank you. I'm not talking about something specific, but generally about foods. Regarding to the eggs, sometimes there is no option to cook it before eating (for example if we make frosting which made of uncooked eggs white) 93.126.95.68 (talk) 03:30, 21 March 2016 (UTC)

Well, the statement as given is pretty much false, in that denaturation relates specifically to proteins, not vitamins. Any degradation of vitamins by heat is due to some process other than denaturation. - Nunh-huh 05:12, 21 March 2016 (UTC)

I believe denature also has a broader meaning, meaning simply "to change the nature of", as in denatured alcohol. Perhaps they are using that meaning. StuRat (talk) 06:11, 21 March 2016 (UTC)

Anyway, here's some references:-

• Effects of different cooking methods on health-promoting compounds of broccoli ("The results show that all cooking treatments, except steaming, caused significant losses of chlorophyll and vitamin C and significant decreases of total soluble proteins and soluble sugars.").
• The effects of cooking on nutrition ("Heating affects mostly the vitamin and fat content of foods... On the other hand, cooking processes that involve heating also make certain nutrients more available for the body to use. For example, the amount of total carotenoids content in carrots and other vegetable-based dishes is higher in boiled versions.").
• Effects of different cooking methods on the vitamin C content of selected vegetables ("This study shows that any raw vegetable contains the highest content of vitamin C compared to that of cooked one. Eating raw vegetables is the best way to obtain vitamin C. Cooking methods (i.e. steaming, microwaving, and boiling) have huge impacts on the vitamin C content of vegetables. Steaming is the best cooking method for retaining the vitamin C content in vegetables.").
• European Food Information Council - The Why, How and Consequences of cooking our food ("Part 2.4: ...The differences in vitamin solubility mean that the method by which foods are cooked has a substantial influence on the final vitamin content. Due to their tendency to disperse in water, water-soluble vitamins in particular are heavily affected by cooking processes that involve immersing food in water for long periods of time e.g., boiling. In contrast, fat-soluble vitamins tend to be lost during cooking processes where foods are cooked in fat e.g., frying, or when fat is lost from the product e.g., grilling.").

So the answer seems to be yes, although this varies according to the cooking technique and the type of vitamin content. Alansplodge (talk) 11:14, 21 March 2016 (UTC)

However, in the case of boiling, since the vitamins leach into the water, the cure is to drink the water, as in soup. StuRat (talk) 16:58, 21 March 2016 (UTC)

You wouldn't have said this if you'd read the sources: "As well as the cooking medium, the length of heating can also affect the vitamin content of foods. Both fat-soluble and water-soluble vitamins are susceptible to heat, with the latter being particularly sensitive.""--TMCk (talk) 18:03, 21 March 2016 (UTC)

I already mentioned that in the first reply. My point is that for foods that really do need to be cooked, for food safety reasons, or to make them palatable, boiling is a much better choice, so long as you then drink the water. Steaming is also good, but frying is bad all the way around. As far as the reduction in nutrition from the heat, eating more can compensate for that. Since veggies have few calories, you can eat quite a few. StuRat (talk) 18:32, 21 March 2016 (UTC)

And e coli. Cook your vegetables as you would cook your beef because the same animals fertilize both. Cooking and 8 billion people are not coincidence. --DHeyward (talk) 09:03, 23 March 2016 (UTC)

With eggs you actually lose vitamins by not cooking - see egg white injury. With other vegetables I'd need to see a specific analysis - breaking down the tissue might release some components to be absorbed, and might allow others to become soluble in cooking water that is disposed of, and might even damage some chemically (though I'm not sure what) ... it really needs an empirical test for a specific substance. Wnt (talk) 11:20, 23 March 2016 (UTC)

What is the substance in eggs which cause them to be foamed while mixing (and at all)?

1) What is the substance in eggs which cause them to be foamed while mixing (and at all)?

2) Are detergents considered foamed substances or they are not? Because I always see that soap has foam. If it is something that is added to the soap, what is the reason for that? Does it help in cleaning? 93.126.95.68 (talk) 03:23, 21 March 2016 (UTC)

1) Albumin causes foam. StuRat (talk) 03:25, 21 March 2016 (UTC)

2) Not directly answering your Q, but note that soap and detergent are two different things. StuRat (talk) 03:48, 21 March 2016 (UTC)

Sodium laureth sulfate is a very common foaming agent and detergent found in bath soaps and the like. EvergreenFir (talk) Please {{re}} 04:12, 21 March 2016 (UTC)

Thank you for your comment. I always thought that the active ingredient in soap is the detergent. 93.126.95.68 (talk) 04:09, 21 March 2016 (UTC)

The wiktionary entry (detergent) claims a detergent is a "non-soap cleaning agent, especially a synthetic surfactant". Personally I'm skeptical. I think it's correct to say that soap is properly a detergent, but that in common usage, if you mean soap, you just say soap, so if you say detergent, you usually mean one of the other ones. --Trovatore (talk) 05:26, 21 March 2016 (UTC)

Ah, the IUPAC Gold Book asserts explicitly that "soaps are ... detergents". I'm not a huge fan of IUPAC and their attempts to uniformize naming, but at least this should provide an example of "detergent" used inclusively. --Trovatore (talk) 05:31, 21 March 2016 (UTC)

The substances in eggs that cause them to make foam when beaten are proteins that trap bubbles of air - see [1]. Richerman (talk) 07:08, 21 March 2016 (UTC)

I know this wasn't your question but FYI the water from a can of chickpeas is usable as an egg-white substitute because it foams in the same way. Apparently it's not known why though. 78.148.107.251 (talk) 23:19, 22 March 2016 (UTC)

Which substance does increase the output while drinking tea or coffee?

I've read in professional article by laboratory professor (here) that tea or coffee cause to increasing in urine output. My question is which substances that are found in these drinks, cause the increasing of the urine output? or by which mechanism if it's known 93.126.95.68 (talk) 04:04, 21 March 2016 (UTC)

The main substance in coffee or tea that causes increased urination is water. In addition caffeine has a modest diuretic effect, but this appears to diminish with regular consumption. Shock Brigade Harvester Boris (talk) 04:09, 21 March 2016 (UTC)

Thank you. But when people drink water they don't have increased urination as they have while the drink tea, water or beer (which all of them actually contains less H2O than water) 93.126.95.68 (talk) 04:31, 21 March 2016 (UTC)

In the case of tea (without sugar or milk), it's got to be over 99% water. StuRat (talk) 05:41, 21 March 2016 (UTC)

Also, drinking any water-based liquid in sufficient quantity would cause the body to urinate to maintain homeostasis. I think what the article you linked is saying is that tea and coffee will increase urination above and beyond what a comparable amount of water would cause. Shock Brigade Harvester Boris is right that the diuretic effect of tea and coffee is almost certainly due to its caffeine content. EvergreenFir (talk) Please {{re}} 05:57, 21 March 2016 (UTC)

That's true for coffee, but tea -- black or green tea (Camellia sinensis), not herbal tea -- has a rather strong diuretic effect, largely due to its theobromine content. Looie496 (talk) 14:11, 21 March 2016 (UTC)

Alcohol (i.e. the ethanol in beer) is, by itself, a diuretic. This is mentioned at Vasopressin#Regulation, see also some popular science coverage [2] [3] and this research article [4]. SemanticMantis (talk) 16:20, 21 March 2016 (UTC)

Perhaps a bit late to the discussion, but as I recall, metabolites of caffeine (e.g. theobromine) cause vasodilation, increased blood flow to the kidney (afferent arteriole) and renal corpuscle, and an increase in filtration into bowman's capsule. This would elevate urine production. I don't remember if there is an inhibitory affect on Antidiuretic hormone as there is with ethanol. If I had to guess, I'd say no.  Wisdom89 ^♦talk 17:44, 22 March 2016 (UTC)

Airplane susceptibility to winds

Why is that when a plane is airborne, it's more susceptible to strong winds and wind shear compared to standing on the ground with engines shut off (ignoring parking brake)? And why the engines of an airborne plane often can't offset a strong wind, while with engines shut off during parking the airplane is capable to stand still? Thanks. --93.174.25.12 (talk) 08:38, 21 March 2016 (UTC)

To a large extent the answer is the parking brake you're "ignoring". An aircraft in flight cannot respond to sudden gusts or changes in wind direction because it cannot accellerate quickly enough. At high altitude during cruise it doesn't usually matter very much but during landing or take-off even a small change in direction, altitude, airspeed, and/or attitude can be catastrophic. While parked an aircraft is not as sensitive to wind because it is not moving relative to the ground and the brakes and tyres provide a lot of resistance to movement. In severe weather parked aircraft can also be tied down to the ground for extra security. Roger (Dodger67) (talk) 12:57, 21 March 2016 (UTC)

(ec) An airborne airplane must maintain controlled Flight by continually balancing the forces of lift, thrust, drag and directional Aerodynamics where every external air movement can cause immediate deviation in any of the flight dynamic angles i.e. pitch, roll and yaw. The control task is so difficult that automatic Fly-by-wire computers are sometimes introduced to replace a pilot's conventional manual flight controls. In contrast, a plane parked on the ground is in a stable equilibrium; it should be safely imobilised against winds by both parking brake and Wheel chocks and its flaps not be left in take-off configuration so that not even a strong wind can lift the plane's weight. There is no need to explain why a plane can park undisturbed in a headwind that its engines would lack enough thrust to fly against. AllBestFaith (talk) 13:03, 21 March 2016 (UTC)

Wind speed increases with altitude. A plane in flight will (generally) be subjected to stronger winds than one on the ground. Iapetus (talk) 13:48, 21 March 2016 (UTC)

The original premise is incorrect. Airspeed is airspeed; it doesn't matter whether the relative motion of air with respect to the airfoil it is caused by natural wind or as a consequence of applying engine power to produce thrust. There are a handful of minor details, like propeller wash, p-factor, or slipstream effect - and these only apply to some types of aircraft (check the official pilot's operating handbook for each aircraft!) - but these confounding factors don't change the basic fact: the wing does not know why air is rushing past it. It will produce lift if there is sufficient airflow.

Some of the most difficult and potentially hazardous elements of operating an aircraft are the difficulties taxiing (driving on the ground) during strong winds.

Have a look at the Airplane Flying Handbook, section on taxiing; and next, take a look at the chapter on Transition to Tailwheel Airplane, for some of the maneuvers pilots must learn to stay on the ground, moving in the correct direction.

As far as shear: low level wind shear is hazardous because it can cause an aerodynamic stall at very low altitude as the aircraft escapes the surface zone and the ground effect. The hazard is because at low altitude, there is very little room for error in applying a correction. Abrupt changes in the wind direction or wind vertical component will require careful, coordinated adjustment of the flight control, angle of attack, and/or engine power. Otherwise, wind shear is no different at altitude or on the ground.

For very small and light airplanes, like Citabrias, the airplane stays parked on the ground during a stiff breeze because it is tied down with ropes. If the winds are strong enough... well, here's a famous video from c. 2014. The wind was very strong - exactly strong enough to cause the airplane to fly (with or without the engine running). Some fast-reacting aviators spun up the engines so that they could maintain control of the aircraft and take them out of the area.

Nimur (talk) 16:26, 21 March 2016 (UTC)

Several redlinks show up in my post: apparently we don't have articles on everything!

Some specific references, for interested readers:

• Low Level Wind Shear: Invisible Enemy To Pilots (from NOAA), on the science and the history, including a fatal 1985 airline disaster
• Our article on wind shear and Low level windshear alert system
• The PHAK, Chapter 11-11, is on Low Level Wind Shear
• On prop wash and slipstream: the Airplane Flying Handbook, Chapter 4, Slow Flight, and certainly elsewhere in the book, there is extensive discussion of these aerodynamic phenomena...
  • The section on high performance maneuvers and slow flight both discuss the risks of wind and gusts during operations that are close to the critical angle of attack.
  • Read and memorize the unintuitive bits. Unintentionally stalling at low altitude still requires the exact same recovery procedure as intentionally stalling at high altitude - pitch forward. Pilots who encounter abrupt wind shear that causes a stall on takeoff must therefore unintuitively steer "toward the ground" to recover from the stall. (The uninitiated pilot may pull back to fly "away" from the ground, but that's not how airplanes work). Reluctance or hesistation to correctly recover from a low altitude stall will bring about a rapid reacquaintance with the ground. Here is a great historical film, Stalling for Fun and Profit Safety (1974).
• There probably ought to be separate articles on deep stalls and tail stalls...

Some time later this week, I'll try to create some articles for those redlinks.

Nimur (talk) 16:40, 21 March 2016 (UTC)

March 22

Dust in air: outside vs inside

Can you reduce dust floating around in the air by opening a window or is there as much dust floating around outside as inside? I don't live near any industrial facilities I would expect to be churning out dust. --78.148.107.251 (talk) 08:52, 22 March 2016 (UTC)

I think that would depend very much on what is going on both inside and outside. Outside you will often find pollen as well as dust, and you need to take into account the direction and strength of the wind. Inside dust will depend on how much movement there is to churn it up into the air. The answer will be sometimes yes and sometimes no. Air conditioning can have filters to eliminate or reduce the dust that enters the room. Electrostatic devices on the market claim to be able to reduce the dust in the air of a room. Dbfirs 08:59, 22 March 2016 (UTC)

Depends on weatherconditions and season. On a rainy day the air outside will be near dustfree. In spring and summer you will have weeks when outside air is so filled with Pollen and/or spores you better keep your windows shut unless it is/was raining. --Kharon (talk) 15:37, 22 March 2016 (UTC)

Desert dust floats around in lots of places - especially in dry climates - and not just the Sahara! For example, here in California, that stuff leaves a mess on the windowsills if you leave the windows open, and it accumulates fast.

NASA has studied atmospheric aerosols and found desert dust at altitudes as high as 15,000 feet above sea level. Not only does natural dust make a mess in the house, it also affects global climate!

Our State Government even publishes this fun comic book, Fugitive Dust Control, from the California Air Resources Board. It's not just a nuisance - it's air pollution! A lot of dust is natural, but human activities like farming, construction, and motor vehicle traffic can significantly aggravate it, especially by getting large particulates up to higher altitudes where natural winds can carry them farther and higher.

Last year, the Pulitzer Prize was awarded to Diana Marcum for her photographic series on the "Dust Bowl" that we've been experiencing for the last few years. We finally got some rain and snow in 2016!

Nimur (talk) 16:17, 22 March 2016 (UTC)

A lot depends on local conditions. On average, indoor environments tend to be dustier by 20-50% than outdoor environments. So on the typical day, opening the windows will improve indoor air quality. However, day-to-day air quality can often see outdoor dust levels swing by factors of 2 or 3. On a day when the external air is unusually bad, opening the windows may make things inside worse. You also don't have to live near industrial plants to have bad air outside. Contaminant plumes can travel hundreds of miles when conditions are right. Here are a couple maps to help look up your local air quality right now [5][6][7]. On the other hand, certain indoor activities, including smoking, cooking, and using a fireplace, can rapidly increase the level of indoor particulates. (This is a huge problem in third-world areas that use coal, kerosene, or firewood for cooking and personal heating.) If you have resources and the inclination, the best way to reduce indoor dust is with a HEPA filter, either on a central AC / Heating system or as a stand-alone unit with a fan. The electrostatic devices Dbfirs mentioned tend to be more gimmick than actual benefit. Most of those have a poor flow rates and so take much longer to clean the air than filters, and they also generate small amounts of ozone which can be more annoying than the dust depending on how sensitive you are to ozone. Dragons flight (talk) 17:43, 22 March 2016 (UTC)

Also, it's not just a matter of which is dustier, inside air or outside air, as air passing through a house tends to slow down and drop it's contents. I've noticed that parking in a carport makes my car much dustier than out in the open, for the same reason. So, opening the windows to reduce dust doesn't seem like it would help. On the other hand, opening a window to change the temperature, humidity, and mix of gases inside the house can help a lot, especially with window fans. StuRat (talk) 17:52, 22 March 2016 (UTC)

In some countries there are flyscreens attached to the windows. It's not just a question of dust, insects can get in as well. 78.149.118.97 (talk) 14:29, 23 March 2016 (UTC)

I think a large part of your decision should not just be about the quantity of dust - but rather what it's made of and what the particle sizes are. Most indoor dust is dead human skin cells (and pet dander if you have one or more pets) - but outdoor dust can be fine soil particles, carbon from diesel engines, cement particles, pollen, all sorts of things. We know that the very fine dust produced from diesel engines is really harmful - for example - and pollen is responsible for a bunch of allergies. So it might be that by opening the windows, you reduce the total quantity of dust by hugely reducing the amount of harmless dust and actually increasing the quantity that is harmful. That consideration makes this be a tougher decision than just "how much dust" would suggest - and it depends a lot on whether you have allergies and/or respiratory problems such as asthma. SteveBaker (talk) 14:30, 23 March 2016 (UTC)

Most indoor dust is outdoor dust that came inside: [8][9]. The oft-reported (and rather icky) claim that indoor dust is mostly human skin is simply a myth. Human skin of course contributes, but unless you've got a serious skin condition you aren't going to be the main source of dust in your home. Dragons flight (talk) 14:56, 23 March 2016 (UTC)

Was just discussing this with a friend. I live in Tucson (desert), 150-feet from a main street, you can see the busses sometimes kicking up dust. In addition to diesel there are fine particles of rubber from the car tires. I asked my friend, who has lived in different parts of Tucson, including next door to me if he thought dust was worse here than other parts, he said, "here." Haven't looked on WP yet for articles on dust but thanks, Nimur for the link to Mineral dust, which is a big problem in Green Valley, 30-miles south of Tucson. Raquel Baranow (talk) 14:47, 23 March 2016 (UTC)

• Lets go back to the OP's question and see it if it it makes practical sense to him.... He indicates that he lives outside a industrial area. If he keeps his windows always closed, the air inside may become dryer (unless he is lucky enough to have an old fashion wife that ignore modern frozen veg and instead boils everything on the wood fired range, instead of shoving it all in the microwave). It is better for health to have a reasonable exchange of out side air- especially if he lives in a modern draft free home. The more moist out-side air will neutralize the electro potential of dust, allowing it to settle. Buy a cheap humidity meter – they are actually rubbish and inaccurate but it will make one more aware of the humidity. If ones eyes feel dry or the nose feels not quite right, it becomes obvious that the humidity has dropped too low. So, don't keep your home too dry. Meaning by that the whole family may get colds because their nasal passages have dried up -which happens with British style central heating. If your worried by dust, then take Dbfirs advice. Invest in a air ioniser. Don't by cheap. For one that is any good at all will cost about a hundred Euros but I have one and it was worth it. Finally cat dander. Some people think they have dust problems because visitors wheeze – even though the home owner don't own a cat. Simpler explanation: In your part of the world, don't bother looking for cats. Just get a shot-gun-licence and stay up for a few nights and blast way at any haggises that try to get into you home. Mind you, wear wellys, as their teeth are razor sharp. Don’t take my word for it – talk to your neighbours.. Get one of those critters cornered and their incisor can go the a rubber gumboot like a hot knife though butter. Which is why you never see them (or being allowed ) to kept as domestic pets in England.--Aspro (talk) 21:13, 23 March 2016 (UTC)

'Posting by banned user removed. Fut.Perf. ☼ 08:45, 25 March 2016 (UTC)

I don't think A/C itself cleans the air. However:

1) Central A/C likely has some air filter(s) to clean the air it circulates. Window A/C units may have filters, too, but in either case they require regular cleaning or replacing to do much good.

2) A/C can generate mold (and mold spores) if the condensate isn't properly drained. Or, even worse, Legionnaire's Disease.

Also, can I ask why you've never switch the extractor on ? Only plan to use it if you burn something badly in the oven ? StuRat (talk) 21:47, 23 March 2016 (UTC)

@ 90.215.70.109 have you ever ventured into your attic (the space above the top floor ceilings and the roof tiles) to look at the ventilation ducking? If you don’t have an attic just look in the loft. You may find it goes through a sort of box with a power cable attached before venting outside. If so, that will be your economizer that recovers heat -to reduce your winter fuel bills. --Aspro (talk) 23:30, 23 March 2016 (UTC)

We do have an article on dust. People with specific medical conditions might pay attention to pollen or dust mites. But I am suspicious that there is a lot of hooey put out by people looking to sell noisy equipment. Our ancestors lived in little huts with a fire in the middle and a little hole at the top to let the smoke out, and we've come a long way since then. And for most non-allergy sufferers, an abundance of antigens is just an opportunity to reinforce immunological tolerance. (A wild speculation I favor is that sniffing flowers is a behavioral instinct to induce just that...) Wnt (talk) 23:57, 23 March 2016 (UTC)

Crude ash content of food

Dog food and cat food labels often indicate the proportion of ash in the food. Our article on kimchi says it contains 0.5 g "crude ash" per 100 g. Our article on ash doesn't say anything about what the term means in reference to food. On the website of an animal feed manufacturer [10] it's explained that crude ash refers to the total mineral content of the food. How do we want to accommodate that information at Wikipedia? Should we have an article on crude ash? Should that term redirect to ash? If the latter, then could someone with a better understanding of the issue than me please add the food-science meaning of ash to the article? —Aɴɢʀ (talk) 21:54, 22 March 2016 (UTC)

The idea for reporting crude ash is that it is an easy thing to measure: just burn the dog food and weigh what's left over. That "crude ash" measurement is almost entirely made up of minerals from animal sources, though plant ingredients may contribute some small amount as well. Meat and bone meal is the source of crude ash in many pet foods. We also have articles on bone meal and blood meal that may be relevant. Crude ash could also be mentioned at Food_composition_data. SemanticMantis (talk) 22:10, 22 March 2016 (UTC)

Read this article and come back if you have any questions. --Jayron32 00:50, 23 March 2016 (UTC)

Fascinating... I always wondered this one too. EvergreenFir (talk) Please {{re}} 06:01, 23 March 2016 (UTC)

Thanks Jayron I intended to link that article too. I do think OP has a good point, and that this should be mentioned on WP, but I can't figure out where either... I almost did a quick redirect to Blood and Bone Meal, because that is what the term (mostly) means in pet food, but that would be misleading for e.g the kimchi claim, where the crude ash I think must come from traces of plant minerals and the fish. SemanticMantis (talk) 14:15, 23 March 2016 (UTC)

I think you can redirect the link to mineral nutrient, because that's what ash is. --Jayron32 18:37, 23 March 2016 (UTC)

Good call, I made the redirect and put an (unreferenced) sentence in near the top; a mild overall improvement IMO. Thanks to OP for bringing this up. SemanticMantis (talk) 20:15, 23 March 2016 (UTC)

uranium or plutonium in nuclear weapons

I had a read through a lot of very nice articles. And it feels like am now capable to built operate and recycle a pit myself. But the thing which is missing is: How many of the US or Russian nuclear pits now in "use" are made from uranium and how many are plutonium ones? The W88 states in a drawing it has a plutonium pit, while the article on B61 nuclear bomb does not give the information. For the Russian nukes it is even more complicated but the Megatons to Megawatts Program makes it clear that they use a lot of uranium which is later used in US nuclear power plants. (Us do not use MOX so it must be uranium). I doubt that you can plug a U-pit into a B61 and after a few years rip it out and plug a Pu-pit in. If this is not a crucial military secret which is also possible there should be a number somewhere.--Stone (talk) 22:34, 22 March 2016 (UTC)

I'd be very surprised if this exact info can be tracked down...most US are plutonium though...I'd be surprised if there's anyone in the govt who's even made an exact tally...seriously..68.48.241.158 (talk) 23:09, 22 March 2016 (UTC)

As the pit article you linked says, the fission pits, or "primaries", in all modern nuclear weapons are plutonium. Uranium is used, not in the "primary", but in the "secondary" of most thermonuclear weapons, for the "tamper" around the fusion fuel. When the weapon is detonated, the uranium tamper absorbs neutrons emitted from the primary and the fusion fuel and fissions. See nuclear weapon design for more details. --71.110.8.102 (talk) 00:43, 23 March 2016 (UTC)

The first place I went looking was to the website of the Federation of American Scientists - www.fas.org - specifically, to their publications and reports on weapon proliferation and fissile materials. These guys are a reliable source, in the sense that they're a bunch of science experts who are well-respected - but their data are independently researched, so take it all with a grain of salt (especially if you're in a decision-making role with respect to nuclear policy!)

Here is FAS's rundown of worldwide nuclear weapons and fissile material; here is their summary status of nuclear weapon states and their respective capabilities. They have lots of data - but it's all well-educated estimates. Chances are, some of the exact information about total weapon capabilities and compositions is highly secretive - although, maybe to a lesser extent than people might expect. A large part of Cold War détente was structured around elaborate and detailed reciprocal disclosure, and effective auditing, of the technical capabilities and stockpiles of all nuclear-weapons states. For example, see the details in our article on the historical Strategic Arms Limitation Talks, which started things rolling... and of course, the New START treaty that is active today; and you can just keep reading about progress up to the present day, such as the proposed Fissile Material Cut-off Treaty, and so on.

As an example of public disclosure: the well-known "aircraft boneyard" of the 309th Aerospace Maintenance and Regeneration Group at Davis–Monthan Air Force Base is a grand collection of American nuclear-weapons-capable aircraft, all intentionally laid out in nice rows so that Russian spy satellites can easily photograph them and count them - to ensure we've actually decommissioned the correct number of weapons platforms! There's reciprocity - American spies can inspect Russian demilitarization too, and (many of) their platforms and technologies are all thoroughly laid out in the open in accordance with treaties, so that nobody has to go to nuclear war over any cloak-and-dagger style doubts.

Heck, you can even sign up for a training course taught by the Department of Defense to learn all about nuclear weapons capabilities, and how we cooperate with (mostly) Russian scientists to ensure that everyone's capabilities are well-understood and comply with the spirit and the letter of international laws. Here's a great list of links to websites of the United States Government that may provide information of interest.

Finally, here is Nuclear Risk, the website of recent Turing Award winner (and co-inventor of public-key cryptography) Martin Hellman - who is also a board member of the Federation of American Scientists. He's got links to lots of useful stories and data pages.

Nimur (talk) 05:03, 23 March 2016 (UTC)

If you visit it, you'll also see the planes are cut in very specific ways. There are also 18 old Titan missile silo's where the concret sliding doors are half-open. It allows inspection of the silo without it looking like a launch threat or an operational silo (they use to rank cities in "first strike scenarios, Tucson was high on the list with 18 MIRV silos, and the graveyard. Not all the planes stored are destroyed strategice bomber, most are supposed to be able to be rebuilt. F-4's, F-5's F-111B are all mothballed. B-52's are cut up.). Just north in Pinal county is a CIA facility as wellas a commercial graveyard. Tiny, no tower airport lined with 747's including the NASA 747 used to move the Space Shuttle. Landed their once to see the NASA plane and was escorted away rather quickly to the little restaurant. ) --DHeyward (talk) 16:31, 23 March 2016 (UTC)

I don't think WHAT we have is particularly secretive...in fact, it's probably the exact opposite, as you suggest...but substantial aspects of how the nuke program is operated are secret, I'm quite sure..all I know is plutonium is what we largely use (exclusively use?) for our nukes....it's less expensive than using uranium (though more messy too)..of course plutonium is made from uranium, but whatever..but whether what we have is plutonium based or uranium based makes absolutely no difference to anybody, including potential adversaries, as the effect is the EXACT same... 68.48.241.158 (talk) 14:27, 23 March 2016 (UTC)

On Thermonuclear War - a famous book by Herman Kahn - addresses that point in his very first chapter: it is difficult for most ordinary people to distinguish between, say, a war that leaves 20 million dead, and a war that leaves 40 million dead - but if we depart from our emotional response and dispassionately consider these potentialities rationally, it is clear that one outcome is preferable to the other. In other words, if you subscribe to the theory of absolutist catastrophism, and pretend that all nuclear war is exactly the same... you're giving up a lot in the way of strategic planning. Nimur (talk) 15:06, 23 March 2016 (UTC)

It's more political than strategic. Ask average U.S. person which war was "worse" - Iraq, Vietnam or WWII. These are order of magnitude difference, not even just double. Compare to Rwandan genocide. Or Spanish flu to Ebola. The reality is that the political staging is more consequential. It's why people oppose nuclear energy even though rooftop solar energy will burn more houses down and kill more people. --DHeyward (talk) 16:17, 23 March 2016 (UTC)

'effect being the same' meaning a 1 megaton bomb is a 1 megaton bomb...doesn't matter if explosive force is created via plutonium or uranium..68.48.241.158 (talk) 15:14, 23 March 2016 (UTC)

Sure, if you gloss over important details like the different construction cost per unit of damage; or the different long term health effects due to variations in, say, how much Strontium-90 radioactive fallout is produced... or any of a zillion other confounding factors! Again, just because the harm is so huge as to be "unfathomable," or because some details are uncertain, does not mean that a strategic planner can never distinguish between the effects. Nimur (talk) 15:21, 23 March 2016 (UTC)

but if you're looking for something that breaks it down specifically, like 912 plutonium and 206 uranium or something...I just don't think that's discoverable and would be shocked it it could be dug up somewhere...it is of note, of course, for countries that are attempting to create nukes for the first time as far as intel...as the uranium route and the plutonium route look different etc etc..68.48.241.158 (talk) 15:05, 23 March 2016 (UTC)

Did you read through any of the links I posted? A group of expert researchers do exactly that in the first source I linked: published estimates of the military stocks of plutonium and highly enriched uranium, broken down by nation, and with pages of additional supporting details. Nimur (talk) 15:09, 23 March 2016 (UTC)

he wants a breakdown warhead by warhead, that info is not in that article...and probably nowhere to be found..68.48.241.158 (talk) 15:20, 23 March 2016 (UTC)

A little deeper reading is in order - this is a heavy subject! Status of World Nuclear Forces, which is a free online summary webpage, and cites additional publications with even more detailed breakdown. For example, Russian nuclear forces, 2015 includes your proverbial "warhead-by-warhead breakdown." From the same list of references, here is the famous "Nuclear Notebook" published by the same group of concerned atomic scientists. Nimur (talk) 15:26, 23 March 2016 (UTC)

Shedding some light on why they do it, here is Counting nuclear warheads in the public interest, (2015), a review article about the history of the Bulletin of the Atomic Scientists public disclosures of warhead estimates. Nimur (talk) 15:53, 23 March 2016 (UTC)

idk still don't see it on a quick glance...if it's there then answer his question! you may not be understanding his question, which is very specific...he wants to know how many war heads in each current arsenal derive their explosive force via plutonium or via uranium....he's not asking about size of arsenal, or a breakdown of explosive force within each arsenal...68.48.241.158 (talk) 16:08, 23 March 2016 (UTC)

Some questions aren't answerable "quickly." The data is all there, in painstaking detail, with summary tables and pages of descriptions... anybody who wishes to spend hours poring over it to recategorize it into arbitrarily-defined bins to answer an arbitrarily specific quesiton ("How many are Type A and how many are Type B") may do so. That would be an arduous and boring and ultimately fruitless task - and I'm somebody who enjoys poring over boring data sets recreationally!

Personally, I think it is more productive to simply read what the other experts have written - how they have approached the problem, how they have categorized the warheads ... but if you want to analyze and refactor their efforts - go for it! There is more public information than there is time for a volunteer enthusiast to process all of it.

If it turns out that your categorization of global weapon stockpiles into counts of "uranium pits" and "plutonium pits" is correct, valid, and useful, you can even submit it to peer-review scrutiny and publish it!

Nimur (talk) 16:23, 23 March 2016 (UTC)

it might be possible that ALL in the current US arsenal are plutonium based...idk...68.48.241.158 (talk) 16:13, 23 March 2016 (UTC)

okay just talked to somebody: pretty sure entire arsenal of US and Russia are technically "thermonuclear" devices currently..ie not atomic bombs, and it's complicated as some uranium is used in these devices for primers apparently, but the 'pit' itself for these are always plutonium based...68.48.241.158 (talk) 16:30, 23 March 2016 (UTC)

just noticed btw that 71 answered OP's question right at the beginning of the thread...pehaps why he hasn't been back...missed that post..68.48.241.158 (talk) 18:41, 23 March 2016 (UTC)

I would not be surprised if the primary not even needed to be a fission bomb, just radiation and neutron generator. The secondary can be lead. Spacing and shape and how much radiation pressure and neutron supplied seem key. An actual primary explosion would require spacing to separate sub critical components as well as spacing to allow the radiation and neutrons to spark the fusion process before primary detonated. Some early types did this though I'm not sure that procedure is still used. It would be much safer to have near-critical amounts of radioactive material and the Lithium/Hydrogen matrix encased in a non-neutron supplying medium. Our article describes the russian 50Mt bomb that used lead instead of uranium. 50Mt was half the yield of a uranium secondary but at that point, what's the need? Bring subcritical plutonium together and the heat can melt the radiation barrier (or remove it through other means). --DHeyward (talk) 19:28, 23 March 2016 (UTC)

That is awesome! I ask a question go to bed work a little on my little Mars-GC-MS and when I look here only have to pick a pdf to read. Thanks to all, especially the one IP. It sounds he would be able to go down into the basement of his workplace and count the pits himself ;-). What I wanted to do to write into the plutonium article and the uranium article a short statement like the one given here: most are Pu, U is not used in large quantities.--Stone (talk) 20:33, 23 March 2016 (UTC)

have to be careful though...if talking specifically about the "pit" in modern "thermonuclear" weapons, you're talking about plutonium....looking at the entire weapon itself, however, a significant component is enriched uranium as well...both components are used, and the way it all works together is quite complicated...too complicated for me to understand...if you're talking about more rudimentary "atomic bombs" then you can make a more clear distinction between plutonium kinds and uranium kinds...68.48.241.158 (talk) 20:51, 23 March 2016 (UTC)

Thanks again. I would only use info with reference, the two articles I what to add this are two Featured Articles so it will take some time before I add the statement that both materials are used even in the same warhead, but the pits are moste likely Pu.--Stone (talk) 21:11, 23 March 2016 (UTC)

March 23

Hospitals inhibiting cell phone signal

I was at a hospital and noticed that my cell phone was getting no signal despite the hospital being in a major (population in the millions) city of a modern industrialized country with generally excellent cell phone coverage. I'm aware some hospitals have a rule not to use cell phones over concerns, founded or unfounded, over cell phones having a small possibility of interfering with medical equipment, but a nurse whom I was talking with told me something I found surprising: she claimed that the hospital not only had a rule banning cell phone usage, but that I was getting no signal because the hospital was somehow inhibiting cell phone signals to prevent anyone from circumventing their rule. Also, I did notice that I got a strong signal outside the hospital, but no signal inside the hospital, though this is not decisive evidence.

So does this actually happen, urban hospitals somehow inhibiting cell phone signals? If so, how widespread is this practice? And what technique or technology does the hospital use to accomplish it? (Deliberate siting in a dead zone outside the range of cell towers? Walls of some particular shape or material? Cell phone jammers? Some other method?)

—SeekingAnswers (reply) 09:03, 23 March 2016 (UTC)

Laws will differ based on jurisdiction, but in the U.S., according to the Federal Communications Commission's website, "Federal law prohibits the operation, marketing, or sale of any type of jamming equipment, including devices that interfere with cellular and Personal Communication Services (PCS), police radar, Global Positioning Systems (GPS), and wireless networking services (Wi-Fi)." - Nunh-huh 09:28, 23 March 2016 (UTC)

• A cell phone jammer would be totally self-defeating in a hospital, since it releases exactly the kind of interference that the hospital wants to avoid. Smurrayinchester 09:29, 23 March 2016 (UTC)

There' no evidence cell phones cause that sort of problem. Interestingly in Britain they tried to bring in some special phones for the emergency services - and they were shown to cause interference! Also they had bad coverage so were a bad idea. I'd have thought there should be some way to have call interception so only emergency service or other authorized calls are allowed. Surely it should be possible to stop people taking their phones out every three minutes and yapping loudly where they shouldn't -- they can go outside first using those appendages called legs if they want to do that. Dmcq (talk) 10:35, 23 March 2016 (UTC)

If they wanted to really curb the use of cell-phones, they would block them (not actively jam them). Although I doubt this is a huge issue. It appears to be just a case of making the safe bet. --Scicurious (talk) 22:00, 23 March 2016 (UTC)

How would you block them? That is the question. —SeekingAnswers (reply) 23:48, 23 March 2016 (UTC)

I have no idea what the reason is, but the observation is credible and it would be interesting to hear more. For example, you might have been under interfering material (some kind of metal shielding for an X-ray station on the next floor up?). Conceivably, a nearby cell phone tower could refuse to continue a connection with you based on triangulation of your position or by spying on GPS in the phone - I don't know if this software exists but it could certainly be written. In that instance I imagine that More Important People Than You would have some special code or their phone numbers on a whitelist or something. Wnt (talk) 11:27, 23 March 2016 (UTC)

The hospital could be a giant Faraday cage. Use metal sheeting on (or within) the walls and roof and glass windows with a thin metal coating. The latter may be used anyway, as they provide better thermal insulation. I know of a building that was an accidental Faraday cage. The architect liked a metal sheeting exterior. After complaints of no or bad cellphone reception (depending on provider), they considered installing signal repeaters. I don't know whether they actually installed them. I imagine this type of hospital building may have been popular in the Cold War, as it is also immune to EMP. PiusImpavidus (talk) 11:33, 23 March 2016 (UTC)

Come to think of it, although most serious medical conditions in a private prison are treated with ibuprofen, prisoners are occasionally brought to hospitals for treatment. This implies that a hospital building's primary purpose is to serve as a prison. Cell phones in prison describes some of the sort of software I was hypothesizing; and I think it is obvious that preventing malingering prisoners from violating incommunicado would be ranked far above any possible medical or personal concern you might have. Wnt (talk) 11:42, 23 March 2016 (UTC)

Your statement makes no sense. You state that occasionally, a prisoner is taken to a hospital to be treated. Then you state that the primary purpose of the hospital is to be a prison. That literally does not follow logically, since the prisoners are in no way the primary population of the hospital... --Jayron32 13:09, 23 March 2016 (UTC)

My assumption is that if one prisoner coordinates an escape or calls up and threatens a victim or orders a hit, heads will roll. If tens of thousands of people complain that they couldn't update their relatives on what's happening, heads will not roll. Wnt (talk) 15:05, 23 March 2016 (UTC)

Wow. In a world full of horses, you really are only capable of seeing zebras. Or unicorns... --Jayron32 18:35, 23 March 2016 (UTC)

This BBC report on the subject shows that there are definite problems in real hospital equipment from real cellphones. It goes on to point out that the phone has to be really close to the equipment to have an effect. I think the conclusion is that phones should be turned off inside treatment areas - but should be fine out in the corridors and waiting rooms.

OK - so that's the pragmatic approach - but you could understand (given the importance of the matter) that in an abundance of caution, they simply apply a blanket rule. That same BBC article says that 64% of doctors admitted that they use cellphones in the hospital in violation of the rules...and that NO deaths have ever been attributed to cellphone interference with hospital equipment.

This FCC page says that it's illegal to block or jam cellphones - and doesn't mention an exception for hospitals. But let's suppose there were some kind of exception made:

• Clearly (as User:Smurrayinchester points out), jamming the signal would be a stupid idea because the jammer would (by necessity) put out more power in those frequencies than the cellphone itself).
• Passively blocking cellphone signals with a Faraday cage around the whole building would actually be counter-productive because the cellphone will gradually increase the power of it's transmissions to the absolute maximum in a failed effort to reach nearby cell towers - so this would be a great way to guarantee the maximum possible radio noise!
• More intelligent (and probably cheaper/easier/more practical) would be to put the faraday cage around the treatment areas to at least shield radio noise from corridors and such - but since we already know that the phone has to be within a few feet of the sensitive equipment, that would also be pointless since the only problematic devices are those INSIDE the treatment areas.

So I VERY much doubt that this hospital was intentionally either jamming or blocking your cellphone. Being in the middle of a large steel and concrete building - possibly on the margins of reception for some other reason - might be enough to produce the effect you're seeing - but I very much doubt that the hospital authorities had done this deliberately. Large/heavy equipment such as body scanners and X-ray equipment could have blocked the signal - and it's plausible that some kind of electromagnetic emissions from such devices was unintentionally interfering with your phone. Either way, moving a hundred yards from that spot ought to have gotten your better reception. Did you actually try that? SteveBaker (talk) 14:16, 23 March 2016 (UTC)

Re: "Either way, moving a hundred yards from that spot ought to have gotten your better reception. Did you actually try that?": I didn't stay in a single spot. After hearing what the nurse told me, I got curious and went all over the hospital, and even to different buildings of the multi-building hospital. My cell phone normally has no trouble getting a signal inside large buildings, but at this hospital, I couldn't get a signal anywhere inside the hospital buildings, but could outside. —SeekingAnswers (reply) 17:34, 23 March 2016 (UTC)

The cell phones in prison article links this product, which apparently is not a cell phone jammer. On the other hand, I found this report of cell phones blocked in a hospital in Ireland due to an adjacent prison with cell phone jamming. Wnt (talk) 15:13, 23 March 2016 (UTC)

I am not sure that a jammer or Faraday cage would prevent a cellphone from interfering with nearby equipment. Would the phone still transmit (perhaps in short, infrequent bursts) as it looks for a nearby tower? Or would it simply listen for the tower and not transmit a reply until it finds one? --Guy Macon (talk) 15:22, 23 March 2016 (UTC)

Depends. Sometimes it drops into analog modes which will drain the battery quickly. But I find it strange that this topic has gone on so long only because my closest hospital has built in WiFi for the rooms. Now if your in the MRI room or the Xray room, no cell phones are allowed. The cardiac monitors to the nurses station are wireless now as well. I'm sure they don't want you wearing a cell phone while hooked up to the monitor. They even had cell phone charging stations in the ER waiting room. What they really don't want is employees spending the day on social media instead of patient care. Day care centers have stricter policies than the hospitals. Hospitals (at least in the US) want repeat business so ERs and Maternity wards are the nicest and most accommodating places. --DHeyward (talk) 16:06, 23 March 2016 (UTC)

This is tangential, but no modern cell phones have an "analog mode". Analog signalling for cell phones was part of 1G systems, which no modern phones support and which have been taken out of service I think everywhere. What will drain the battery is the phone boosting its transmission power if it can't connect to a tower, to try to connect to towers that might be farther away. --71.110.8.102 (talk) 01:30, 24 March 2016 (UTC)

@71.110.8.102: - Meh, I have an old phone. But seriously, SMS is one of the oldest formats used in pagers ans uses the AT modem command set. Certainly later GSM and 4G LTE have made it digital but I still believe the U.S. with Verizon and others that avoided GSM initially still have some analog service in rural areas and for compatibility a TDMA phone can drop into analog mode. I haven't looked in a while but see if any of those carriers still support TDMA (Qualcomm took over the market with 4G CDMA and FRS is all but gone but I think some of phones still support analog for SMS even if they can't make a call). Pagers still exist. If your phone works in the U.S. but not Europe or Japan, I think it still has analog communication capability. China went CDMA but I think they avoided paying Qualcomm. CDMA licensing dominates Qualcomm earnings. --DHeyward (talk) 07:43, 24 March 2016 (UTC)

Our Advanced Mobile Phone System and History of mobile phones article suggests all analog or digital AMPS was shut down in the US by 2008. As for pagers, our article suggests there are a whole host of different systems used both local and wide and that these systems are usually distinct from mobile phone systems (which is an advantage for numerous reasons). It's not clear to me if any of them are analog, but neither that article nor our Short Message Service article suggests SMS was ever used for pagers (the SMS originated with GSM not with analog networks). SMS may be used for message submission and partly analog systems may have been used to submit SMS (e.g. Telelocator Alphanumeric Protocol) but those are different issues. Getting back to pagers, our article suggests FLEX protocol is the most common one used in the US nowadays at least for wide networks and it seems to be digital. Nil Einne (talk) 18:41, 24 March 2016 (UTC)

It's quite possible the hospital may have taken counter-measures that are counter-productive. The person(s) they assigned the task of ensuring that cell phones can't be used in the hospital may not even be aware of the reason. I like to use the example of speed bumps, which are designed to slow traffic down, to make roads safer. However, when you combine people who see them swerving to avoid them and those who don't see them losing control of their car when they hit them at high speed, they may very well make the roads less safe. StuRat (talk) 17:54, 23 March 2016 (UTC)

No matter where I stand in my apartment, my smartphone registers a low level signal (only two bars), but if I initiate a call, the level immediately increases to maximum (all bars). This implies that the cellphone towers transmit at low level when idle, but increase power when actually interacting with a device. It might be interesting if the OP had initiated a call while inside the hospital - it may have been successful. Most users simply start a call without looking at the level; by checking it he may have been unnecessarily discouraged. Akld guy (talk) 21:24, 23 March 2016 (UTC)

I would expect that cell phones would then adjust the signal meter depending on if it's during a call or not. Perhaps yours has poor software. StuRat (talk) 23:38, 23 March 2016 (UTC)

I do not understand your response. It does not seem to bear any relationship to my suggestion that the cellphone tower increases power. Are you saying that my cellphone should misrepresent the signal level that it receives? This is a 6-month-old Samsung 5 with all available updates installed. Please clarify what you meant. Akld guy (talk) 02:18, 24 March 2016 (UTC)

The cell phone knows if it is currently making a call or not. If it's customary for cell towers to increase power during a call, then the cell phone manufacturers would adjust for that in the signal bar, say by showing twice as many bars, when the phone was not in use. This would make customers happier, since they would see more bars. (Of course, they wouldn't want them to always see full strength bars, as then they would be pissed when they couldn't make a call, and call customer service and complain that their phone was broken.) Think of a voltmeter which has different settings with different sensitivities displayed on the meter. StuRat (talk) 02:28, 24 March 2016 (UTC)

Utter nonsense, sorry. You're asking me to believe that a cellphone that hadn't initiated a call via a celltower could predict the full-power output of that tower? Not only that, but whatever level it predicted would be a misrepresentation. C'monnn. Akld guy (talk) 02:54, 24 March 2016 (UTC)

If there is some standard practice, like cell towers boosting to twice the strength during calls, then the cell phone makers would know that and use it. And it's not misrepresentation, since there are no units listed on the bars. The usual interpretation is that it's a percentage of max. If you have 5 bars possible, then 4 bars is 80% of max, etc. So, if they know what the max cell tower output is under each scenario (during a call or not), 4 bars should be 80% of that max. StuRat (talk) 16:28, 24 March 2016 (UTC)

Your last sentence implies that you're assuming that maximum cell tower power always equates to all bars lit. No more, no less. Well duh, signals can be so strong that they're right off the scale at more than 5 bars, which of course displays can't show because they're limited to 5 bars. Do you have any experience with radio receiver LCD S meters as I do? You're presenting hypothetical situations based on OR theories about cellphone makers misrepresenting signal levels to their customers. Provide some evidence that they manipulate levels. Akld guy (talk) 20:57, 24 March 2016 (UTC)

I've been in our local hospital many times and I can get a signal in only a few areas. I thought that it was probably due to all of the steel used in the construction or all of the electronic equipment, but I don't know. Bubba73 ^{You talkin' to me?} 01:53, 24 March 2016 (UTC)

March 24

Is gray matter of CNS - just collection of the bodies?

I'm reading now in a textbook that "Cell bodies are located in the gray matter of the CNS, and their collections are called ganglia in the PNS and nuclei in the CNS." Does it say that the gray matter of CNS is just collection of the bodies and the white matter is the collection of the Dendrites? If it is, what is the reason for the grey color of the bodies? is it because of that the bodies have nuclei?93.126.95.68 (talk) 00:06, 24 March 2016 (UTC)

The difference in color between gray matter and white matter is largely that the latter contains myelin whereas the former does not. --Jayron32 00:13, 24 March 2016 (UTC)

A big reason is neuromelanin - see [11]. Indeed, there is a substantia nigra in the brain ... yes, we have all been slandered with a racial epithet. :) Also a locus coeruleus. The source I cite suggests all these wonderful colors are about protecting the brain from free radicals and metals. Quite possibly they're right. But melanin's highly complex structure reminds me of an earlier era when strands of sugars bound to four nitrogenous bases in random order were assumed to have some modest structural role ... I wouldn't rule out the possibility of a big surprise here. Wnt (talk) 00:18, 24 March 2016 (UTC)

Thank you for your comments. What about the text that I brought? What does it mean to say? 93.126.95.68 (talk) 00:38, 24 March 2016 (UTC)

It says basically that Grey matter is where the cell bodies of the neurons are located. Concentrations of gray matter are called ganglia in the peripheral nervous system and nuclei in the central nervous system. If you read those articles, you'll learn more about those terms. --Jayron32 01:30, 24 March 2016 (UTC)

The answers about are pretty much correct. However, I must quibble with the idea that "cell bodies are in gray matter, dendrites in white". This is only the case for neuronal cell bodies, and even then not exclusively so. There are plenty of oligodendrocytic, astrocytic, microglial and endothelial cell bodies in the white matter. Also, whilst neurolaminin is indeed important in giving the substantia nigra its colour, it is not responsible for the making the grey matter grey (it's more a dirty yellow sort of colour in fresh brain anyway, the white matter is indeed fairly white in my experience). Fgf10 (talk) 08:18, 24 March 2016 (UTC)

Is it known which substance (ingredient) in cow milk causes to sleepiness?

93.126.95.68 (talk) 01:35, 24 March 2016 (UTC)

This source claims that any protein-rich food should induce drowsiness, so milk can do so, but not exclusively milk. --Jayron32 01:45, 24 March 2016 (UTC)

Is that also true for turkey? Or is it just because we eat too much of it at one sitting? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:47, 24 March 2016 (UTC)

Yes, overeating definitely causes sleepiness, as does the excess protein and tryptophan. StuRat (talk) 01:50, 24 March 2016 (UTC)

Mother Nature's way of directing your body's focus toward digestion? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:55, 24 March 2016 (UTC)

Basically yes. While tryptophan can cause sleepiness, and tryptophan (as an amino acid) is present in the proteins of milk and turkey (and lots of other foods), the sleep-inducing effects of tryptophan cannot be induced by turkey or milk alone. I believe the source I cited notes that one would need to eat a stomach rupturing 40 pounds of turkey meat to get enough tryptophan to induce drowsiness. Protein-rich foods are themselves enough to induce drowsiness, according to same. --Jayron32 02:02, 24 March 2016 (UTC)

Yep, like a snake who swallowed a pig. StuRat (talk) 02:02, 24 March 2016 (UTC)

Isn't it supposed to be warm milk ? That suggests it's a psychological thing, since warm milk is associated with being a baby, much like the white noise of the womb, and the fetal position, things also sometimes used to make you "sleep like a baby". StuRat (talk) 01:54, 24 March 2016 (UTC)

Google "warm milk and sleep" and many claim it's a myth. However, it also says milk contains tryptophan, as with turkey. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:57, 24 March 2016 (UTC)

See source above. While enough tryptophan can, of its own accord, induce sleep, you cannot get enough of it through either milk or turkey, or really any foodstuff, to do so. --Jayron32 02:04, 24 March 2016 (UTC)

Besides the too small amount of tryptophan to cause drowsiness, I wonder if the problem is also that it does not reach the brain when taken orally. Llaanngg (talk) 18:58, 24 March 2016 (UTC)

Presumably because different things work for different people. As far as finding one universal sleep aid, well, propofol might work, but Micheal Jackson found that's not a wise choice. StuRat (talk) 02:02, 24 March 2016 (UTC)

Milk is also rather high in sugar content. Hyperglycemia. I used to drink several gallons a week. I gave it up when I was diagnosed as diabetic. Nowadays when I do have a sip it tastes as sweet as fruit juice. μηδείς (talk) 02:32, 24 March 2016 (UTC)

There is an article analyzing the link between food and drowsiness. Llaanngg (talk) 19:00, 24 March 2016 (UTC)

The article on "specific impulse" seems to mix up force and mass (physics)

In the article on Specific impulse. It specifies that "If mass (kilogram or slug) is used as the unit of propellant, then specific impulse has units of velocity." this statement may be correct. But! "If weight (newton or pound) is used instead, then specific impulse has units of time (seconds).". Weight is supposed to have unit in mass not force? I suspect there's some serious mixup here. Anyone care to scrutinize this from a physics standpoint ? Ferrofield (talk) 04:01, 24 March 2016 (UTC)

It's correct. Thrust is force (mass * length/time^2)). If mass is used, the rate of consumption is mass/time. Divide and you get (length/time) which is velocity. Weight, though, is also force (a kilogram is mass, a pound is force - knowing weight is not mass is critical here). (force/(force/time)) = time. It's a measure of efficiency. You are either measuring how quickly the rocket is getting lighter for a given thrust to weight ratio or you are measuring how far the rocket has moved for a given amount of time. --DHeyward (talk) 07:10, 24 March 2016 (UTC)

Shouldn't it say "If force [N] is used instead, then the specific impulse has units of time (seconds)." ? Ferrofield (talk) 15:25, 24 March 2016 (UTC)

In physics, weight is a force. Weight can be measured in pounds, which are a unit of force.

In many other contexts, we know that the weight is measured on Earth, so we can easily translate between weight and mass: these two parameters are related by the g (little g) standard gravitational constant.

When people are sloppy, they interchange mass and weight freely. But in our article on specific impulse, we are being precise: weight is a measurement of force. "Pounds" are a unit of force, not a unit of mass.

Some people choose to clarify this distinction by separately defining two different units: Pound (force) and Pound (mass) - but they're really just formalizing a sloppy conversion. To make matters even worse (!) - even if the author intends to distinguish between "pounds force" and "pounds mass", and diligently works to ensure correctness, in common speech many English speakers elide the qualifier and simply say "pound", yielding a linguistic collision.

In our Wikipedia article on specific impulse, and most of our other physics articles, we totally avoid this confusion by using pounds to refer only to force. If you want to use an imperial unit of mass, use the slug (mass). Alternately, you can use SI units.

Nimur (talk) 16:32, 24 March 2016 (UTC)

You could use "force" but it would be more confusing, I think. People understand intuitively "Thrust to weight ratio." That's a dimensionless term since thrust is Newtons and weight is Newtons (or "pounds"). The "impulse" is thrust to weight ratio with the added "and thrust to weight ratio improves because the rocket is expelling part of its weight in Newtons/sec)." The dimensions work out but what's missing and might be confusing is it's an integral approaching an ideal Dirac delta function. Ideally, a rocket would have infinite thrust and expel all it's fuel in 0 seconds so it doesn't have to lift the fuel. That 0/0 equation has an integral solution. The difference in using mass (slug/kilogram} or weight (pound/Newton) lets the engineer calculate lift efficiency. Using mass, a moon rocket can be compared to an earth rocket as it will be the same efficiency, but using weight shows the difference in the the amount of burn necessary. An identical rocket motor expels mass at the same rate on the moon as it does on earth and has the same thrust but not the same weight. The rocket weighs less on the moon so the thrust to weight ratio is better - that means less burn time and less fuel (i.e. "seconds" of burn). When calculating efficiency and capability, both metrics are useful/needed but you can't lose sight that it's an integral and units aren't independent of the fuel, mass of the rocket or thrust. --DHeyward (talk) 16:56, 24 March 2016 (UTC)

Tiny nitpick: an identical rocket on the moon has about one atmosphere less back-pressure on the exhaust system - which has a nontrivial effect on the exhaust mass rate and the flow expansion characteristics. To really get into the details, we'd have to do some "rocket science" - but anyone who looks at, say, the iconic bell nozzle of the Apollo Service Module Service Propulsion System - and compares the bell nozzle shape to, say, the F-1 engine, you can almost intuitively feel that one of those engines was designed to exhaust into vacuum, and one was designed to eject exhaust at sea level. For any particular ambient backpressure, there is a particular nozzle expansion shape that will encourage laminar flow for optimal energy and momentum extraction, even at the same Isp. Nimur (talk) 17:44, 24 March 2016 (UTC)

Must admit that on first reading, the article did not make complete sense to me either. So,what may help too, is a sentence or two explaining that the velocity of the exhaust is dependant on the total molecular weight (molecular mass) of the combustion products. Which is why Hydrogen & Oxygen is favoured for the higher speeds required for obit insertion and of interplanetary probes. In practical engines, the unit of mass ejected has little to do with the resulting velocity. One could construct a whooping big engine that ejects a ton of lead oxide per second but stays firmly on the launch pad or a smaller engine with the same starting wet weight that ejects a ton of super heated H2O per second and brakes the sound barrier within seconds of being launched. Therfore , this article would benefit I think, from an explanation that all fuels are not equal and that very much affects SPI per unit mass. As a thought experiment: imagine one is sitting just outside the airlock on the ISS with two balloons. One is full of hydrogen and the other (smaller) balloon is filled with the same mass of gas but of CO2. There is no air resistance to worry about. Let go of both necks at the same time. Which balloon will zoom away fastest? The math is the same and the starting mass is the same but it is the velocity of the exhaust that makes the difference to the SPI. This molecular mass bit, the article fails to include explicitly for clarity. Other than that, I think that the article is pretty comprehensive and well structured.--Aspro (talk) 20:31, 24 March 2016 (UTC)

Wouldn't "If force (newton or pound-force) is used instead, then the specific impulse has units of time (seconds)." be more correct? Currently it seems to use weight as a substitute for force and a lot of loosely specified imperial units. Ferrofield (talk) 02:21, 26 March 2016 (UTC)

A reflection on black hole event horizon (physics)

A black hole event horizon is supposed to be the final end of interaction of anything falling into it with the outside world, besides hawking radiation and preservation of information. Now suppose the gravity exerted by the black hole is measured externally and an object less massive than the black hole falls into it. Will the gravity of the black hole plus an object outside of it become less in magnitude when the external objects falls into it? Such that the event horizon has the ability to chop gravitational interaction? Ferrofield (talk) 05:06, 24 March 2016 (UTC)

No, the mass of whatever falls into a black hole adds to the mass of the black hole. -- BenRG (talk) 09:13, 24 March 2016 (UTC)

Indeed, the mass (and therefore the gravitational force), the electrical charge and the spin of the incoming object all add to whatever the black hole had before it 'consumed' it. Conservation laws do apply to black holes. SteveBaker (talk) 13:02, 24 March 2016 (UTC)

So light which is an electromagnetic phenomena with the propagation of 3*10^8 m/s can't break free. But gravity with the same wave nature and propagation of 3*10^8 m/s goes straight through. Kind of like the black hole where selective about which wave types it permits to escape. It's like it's permeable for some type of waves and not others. Perhaps there are other wave types yet undiscovered that would enable one to see what's inside? (if 2800 light years won't degrade the resolution too much) Ferrofield (talk) 15:17, 24 March 2016 (UTC)

Um, stop right there. Your statement " gravity with the same wave nature and propagation" isn't necessarily an established way to think of gravity. Gravity has not been properly explained by the standard model and thus analogies between gravity and other standard model forces (like electromagnetism) and their gauge bosons like photons or light are not valid. You simply can't treat gravity like light and ask what a black hole does to gravity. While the standard model did not exist at the time of Einstein, he DID have an intuitive sense that gravity as a force did not work like other forces, which is why he treated gravity as a pseudoforce and developed general relativity to explain the phenomenon of gravity without having to resort to treating gravity like light or other phenomena, which causes all sorts of problems. --Jayron32 15:58, 24 March 2016 (UTC)

Also best keep apart gravity itself and that ripple called "gravity wave" (caused by some interaction of bodies of huge mass) which is more precise a ripple in time or time-space, not a ripple in gravity!! --Kharon (talk) 17:03, 24 March 2016 (UTC)

The equivalence principle implies that you can treat gravity in more or less the same way as electromagnetism for this purpose (at least for a small object falling into a large hole). The Standard Model's gauge forces are actually similar to gravity; mathematically they are like general relativity applied to compact extra dimensions. And electric and gravitational charge are both preserved, so there is no difference that needs explaining here. -- BenRG (talk) 18:26, 24 March 2016 (UTC)

As SteveBaker said, electric charge (which is the electromagnetic equivalent of mass) is also preserved. It doesn't disappear. There is no difference between gravity and electromagnetism/light in this regard. There are various ways of thinking about this. One way is that the field is an entity unto itself which can't disappear for geometric reasons, much like you can't untie a knot in a rope if you don't have access to the ends. Another way is that you never actually see the object cross the event horizon; it's always just outside, where it can still "emit" the field for you to detect. -- BenRG (talk) 18:26, 24 March 2016 (UTC)

Yeah, the question of how the gravity escapes the black hole is a long-standing one. One thing I wonder -- if you look at something falling into the event horizon, it is said that it is always hypothetically visible since there is always the chance of some absurdly red-shifted photon finally outrunning the infalling space (???) of the event horizon and getting out. But you can't see it because the photon emission is minimal. However, from our frame of reference the mass of an infalling object, travelling at almost the speed of light, should grow without limit, right? And that tremendous and super-fast-moving mass ought to emit some kind of gravitomagnetic radiation, shouldn't it? Which leaves me thinking someone who knows a hell of a lot more physics than I do could work out some kind of limit calculation for how much the gravitomagnetic emission vs. the redshifting comes out to be. If you can redshift gravity that is. Am I just gibbering? :) Wnt (talk) 23:39, 24 March 2016 (UTC)

If the sun would disappear in an instant. How long would it take for us to know? I suspect the propagation delay is 3x10^8 m/s. So whatever it is, it has some properties that can be explored. Say if one can design a device that can sense really small gravity changes and have high angular resolution. And have this sent to orbit close by a black hole. Perhaps one would discover something about what happens on the inside. Ferrofield (talk) 21:43, 25 March 2016 (UTC)

Egg white whipping with contaminants

Can egg white be whipped into a foam if it already contains sugar and cocoa powder or will these prevent that? ----Seans Potato Business 07:59, 24 March 2016 (UTC)

Contamination from copper seems to help with whipping eggs, and the foaming is a result of denaturing and air insertion. I can't imagine sugar and cocoa powder preventing denaturing of the egg whites. It might affect the form of the foam, but that's just a guess. Ian.thomson (talk) 08:21, 24 March 2016 (UTC)

Those things make whipping more difficult if they are added at the very start, but I don't think they will prevent it. Note though that even a little bit of fat can make it impossible to whip egg whites. Looie496 (talk) 14:30, 24 March 2016 (UTC)

This suggests to me that one needs to look into if certain substances will bind to or interact with the substances in the egg white in a way that prevents denaturing or stable bubble walls. Ferrofield (talk) 15:21, 24 March 2016 (UTC)

Sugar improves the stability of whipped egg white - Meringue#Chemistry actually discusses this issue in some detail although the section lacks sources. Roger (Dodger67) (talk) 16:15, 24 March 2016 (UTC)

Entropy. Statistical mechanics. Information ~ Energy

Question

Remark

In this source [exergy.se/ftp/exergetics.pdf, pages 70-77] author writes: Assume a system of N unique particles. The number of allowed states Ω of the system is exponentially depending on N. Let the probability of the j:th state be Pj and the sum of the probabilities of all states to be 1, i.e. the system is in at least one state $\sum _{j=1}^{\Omega }P_{j}=1$ The entropy of the system is then defined from statistical mechanics as $S=-k\sum _{j=1}^{\Omega }P_{j}\ln {P_{j}}$ ... Let us exemplify by a system of N different particles with 2 possible states each, e.g. 0 or 1. Then we have $\Omega =2^{N}$. If there are no other restrictions then all $P_{j}^{0}$ must be $2^{-N}$, see the Table below. Is it correct? We know form Boltzmann's entropy formula that $W={\tfrac {N!}{\prod \limits _{i}{}N_{i}!}}$ , where $N=\sum _{i}N_{i}$. Taking the logarithm of W, we have $\log W=\log N!-\sum _{i}\log N_{i}!$. Applying Stirling’s theorem, we obtain $\log W=N\log N-N-(\sum _{i}N_{i}\log N_{i}-\sum _{i}N_{i})=N\log N-\sum _{i}N_{i}\log N_{i}$ $=\sum _{i}N_{i}\log N-\sum _{i}N_{i}\log N_{i}=\sum _{i}N_{i}(\log N-\log N_{i})=\sum _{i}N_{i}(\log {\tfrac {N}{N_{i}}})$ $=N\sum _{i}{\tfrac {N_{i}}{N}}(\log {\tfrac {N}{N_{i}}})=-N\sum _{i}{\tfrac {N_{i}}{N}}\log {\tfrac {N_{i}}{N}}$. Let $p_{i}={\tfrac {N_{i}}{N}},{\text{ for }}i=1,2,...,m$. Then $\log W=N(-\sum _{i}p_{i}\log p_{i})$ and $S=k\log W=kN(-\sum _{i}p_{i}\log p_{i})$. So first, we must add factor $N$ (BTW in wiki articles also $N$ is absent). Second, $m$ is a number of existing states among all particles, not all possible states. So we count only system states, which consist of same set of particle states. E.g. we have 5 particles of which 2 are in state 0 and 3 are in 1. E.g. we have system 00111. Now we can consider only 00111, 01011, 01101, 01110, 10011, 10101, 10110, 11001, 11010, 11100. We cannot compose 00000 or 11111. In this example we have $m=2,N=5,N_{1}=2,N_{2}=3,W=10.$ So why author believes $\Omega =2^{N}$ and counts $j=1,2,...,\Omega$??? Is it correct?

[ https://en.wikipedia.org/wiki/Boltzmann's_entropy_formula ] [ http://exergy.se/ftp/exergetics.pdf , pages 70-77]

37.53.37.94 (talk) 20:07, 24 March 2016 (UTC)

The author doesn't believe this: he defines it. He has explicitly stated that his hypothetical system has N independent variables that may each take only one of two possible states. This is definitional or axiomatic - he constructed the problem so that he could work out the math that follows from it.

This formulation is nearly identical to what shows up in my textbook on thermodynamics, Stowe's Introduction to Thermodynamics and Statistical Mechanics. It's a pretty standard formulation, because it's a simple way to work the math.

I've never heard of this particular author - so I'm not going to vouch for the entirety of everything else he's written: in particular, his unique terminology "exergy" is not commonly used in other books on statistical physics. Reading through some more of his material, I'll say this: his book is clearly the work of a non-native English speaker, and it doesn't look like he had a very good editor. I would not use his book as your primary reference for anything, let alone for information on standard formulations of thermodynamics - even if some parts of his book are correct, there are plenty of much better resources. I can personally vouch for several other great books on statistical mechanics if you're interested; and we have a list of references in our article on thermodynamics.

Nimur (talk) 20:10, 24 March 2016 (UTC)

Exergy wasn't taught in the physics classes I remember either, but it has been around a while and I have encountered it in the wild before. I'm too lazy to try and verify if he is using the terminology in the same way that others have used it. Dragons flight (talk) 19:50, 25 March 2016 (UTC)

But with this formulation he calculates entropy wrong way. He must take $j=1,2,...,m$. If particle states are 0 and 1 , $j=1,2$.37.53.37.94 (talk) 20:53, 24 March 2016 (UTC)

in particular, his unique terminology "exergy" is not commonly used in other books on statistical physics -- This is book not on statistical physics. This book about exergy. And this word is not unique [see http://www.collinsdictionary.com/dictionary/english/exergy ]. Quality of the book isn't the subject. I've leafed through your book and it does not contain info I'm looking for. In your book you write $\Omega =\omega ^{N}$ too. So your book also does not agree with wiki article Boltzmann's entropy formula. E.g. let system have 5 non-distinguishable atoms of helium. Every particle can be in state 0 or 1. Two atoms are in state 0, Three atoms are in state 1. How will you calculate number of system states $W$, which is used in formula $S=k\log W$? And why? 37.53.37.94 (talk) 04:47, 25 March 2016 (UTC)

Question

Remark

And 2nd question. Can human generate information (and so energy) by brain activity: thinking and processing? For me it's important to distinguish both these types of activity. I know that from knowledge of particles' speed we can generate energy (Maxwell demon). But it is not brain activity, but measurements. And I also know brain is processing huge amount of data. But I feel brain does the job only for own purposes (human survival). If we are talking about processing, then decoding also is present. So we can use Shannon information. But I can't assemble the puzzle. Brain decodes information (e.g. from eyes) and then answers. To minimize processing it can use instincts, learning (it's much harder as connected with statistics collection to estimate probabilities). If neither instincts nor learned patterns fit, then brain thinks.

37.53.37.94 (talk) 21:12, 24 March 2016 (UTC)

Here's some questions for you to consider: Is there more information in one-minute of white noise or one minute of the Crab canon? Or what about a one-minute of me speaking this comment? Shannon would say white noise has far more information, but that doesn't necessarily match up with our intuitive notion of information. As for generation: can a farm consisting of sheep, pigs, and cattle generate information? Note that one of the most popular Diversity_indexes used is in fact just Shannon's entropy, more on that here [12]. So if we calculate the Shannon diversity of a given paddock, it will change on a day-to-day basis based on the which animals are there, and we could perhaps claim that the animals are creating information, sort of Maxwell's livestock as an analog to Maxwell's demon. My point is that it's pretty easy to compute some H and say "there's this much entropy/information in this system", but the interpretation of that claim is subtle and often depends on many other implicit assumptions and models. SemanticMantis (talk) 14:26, 25 March 2016 (UTC)

March 25

Amplitude stabilisation of sinusoidal electronic oscillators

Im looking for refs concerning the theory of stabilisation of sinusoidal oscillators using non linear semiconductor components. Any offers?--178.111.96.35 (talk) 01:15, 25 March 2016 (UTC)

HP200A has several references. --Guy Macon (talk) 05:08, 25 March 2016 (UTC)

Fast Amplitude Stabilizing of an RC Oscillator Wein bridge oscillator with incandescent lamp stabilization LC Oscillator has stable amplitude High-Purity Sinewave Oscillators with Amplitude Stabilisation. AllBestFaith (talk) 10:58, 25 March 2016 (UTC)

How to block out female pin headers

I brought a JTAG programming cable but the the key-way pin of the header isn't properly "blocked out". The end in question is a 1.27mm pitch female header. What's the name for the part used to "block out" certain female header pins? Alternatively a link to Digikey for the right part would help too. Johnson&Johnson&Son (talk) 06:31, 25 March 2016 (UTC)

See Pin header#Polarizer key. AllBestFaith (talk) 11:06, 25 March 2016 (UTC)

Thanks. Is there any place that actually sells 1.27mm pitch polarizer keys? I tried Digikey and couldn't find any there and they pretty much have the biggest selection. Johnson&Johnson&Son (talk) 12:56, 25 March 2016 (UTC)

Sorry if this is way off: Here [13] is a rack of 24 pins, perhaps one of them would suit your needs. SemanticMantis (talk) 14:11, 25 March 2016 (UTC)

Here is a range of headers but for blocking one hole of a female header, consider gluing a male pin in place. AllBestFaith (talk) 14:13, 25 March 2016 (UTC)

The male pin would be conductive though unfortunately. I guess I'll use that as a last resort. It's weird though, both the male and female headers are so widely available, and yet a supposedly common accessory like the polarizer key is so hard to find.Johnson&Johnson&Son (talk) 14:31, 25 March 2016 (UTC)

Yeah - don't use anything conductive. If I don't have a proper blocking pin to hand, I generally put a squirt of glue in there with a hot-glue-gun. Don't squirt too much in there because it can ooze out and block other pins too - but a tiny amount does the job perfectly. SteveBaker (talk) 14:45, 25 March 2016 (UTC)

I see the value of being extra careful, but isn't the point that the block is just to make it impossible to plug something in the wrong way? E.g. if plugged in correctly nothing should be touching that socket, so it shouldn't matter much if it's blocked with a conductive pin or glue. Maybe I've gotten something terribly wrong and backwards, but clarification would be appreciated. SemanticMantis (talk) 16:03, 25 March 2016 (UTC)

The idea is that you cut off one of the pins on the male connector (typically at one end of the block) and fill in the corresponding hole on the female connector. If you try to insert the connector with a 180 degree rotation by mistake, then the blocked hole hits an un-cut pin and you can't push them together. Hence blocking one pin suffices to prevent the cable being plugged in backwards. You can use the same kind of trick when you have two or more identical-looking connectors to make sure that the correct cable is plugged into the socket. Cutting and blocking multiple pins in different places along the header allows for some considerable control over which connectors go onto which headers as well as ensuring they aren't plugged in backwards. SteveBaker (talk) 19:59, 25 March 2016 (UTC)

What is needed is a cock header. Something that probably doesnt exist atm but cuould do with inventing.--178.111.96.35 (talk) 00:12, 26 March 2016 (UTC)

WP:WHAAOE. See Urethral sounding. Tevildo (talk) 00:15, 26 March 2016 (UTC)

File:Salt Lake.JPG

Greetings, does someone know what File:Salt Lake.JPG is a photo of?Jo-Jo Eumerus (talk, contributions) 15:15, 25 March 2016 (UTC)

The uploader was User:Mountainloverk2, who sadly has not edited in 8 years. I don't see anything that can be used to identify the picture to more specific than a body of water in a dry landscape. The plant life appears to be part of the American West in some way, but there's nothing in the picture to nail it down specifically. If it is a real salt lake in the American West, it could be part of the massive endorheic basin which occupies much of the west. See Great Basin. I do note that the landscape looks roughly like the landscape in some pictures in that article. That giant area is far too vague to be useful in determining the location of the body of water, and there's other similar desert areas in the American West or Mexico in which this would fit as well. --Jayron32 15:25, 25 March 2016 (UTC)

And I'm probably wrong, because the uploader also uploaded a whole slew of pictures from locations in Pakistan such as File:Crossing Khanwal Luck.Jpg from I think Khanewal District, all around the same time as this picture. So, maybe Khanewal District? No idea though, certainly nothing to nail it down closer than that. --Jayron32 15:29, 25 March 2016 (UTC)

I bit on this one and noticed that there is an EXIF date for August 14, 2006, which is matched only by File:Nawabshah1.JPG. See Nawabshah. Since this is a "digitized on" date I'm not sure it's even weak proof the two were taken close together. I do see that searching for salt lakes in Sindh pulls up vaguely similar-looking terrain, to my bleary eyes, e.g. [14]. Wnt (talk) 16:52, 25 March 2016 (UTC)

Old cod liver oil capsules useless?

Am I right in my interpretation of this article that cod liver oil capsules which are over a year out-of-date have probably oxidised and become useless?

Yes, and not only useless, but potentially harmful. One trick is to open one (over the sink) and smell it. If it smells bad, it is bad. StuRat (talk) 02:01, 26 March 2016 (UTC)

You're best off discarding any consumable thing that's way past its expiration date. — Preceding unsigned comment added by Baseball Bugs (talk • contribs) 02:45, 26 March 2016 (UTC)

Isolated neutron--how many neutrinos go thru it, or at least strike it, per second, at least on Earth with the average flux here?

I've heard that zillions of neutrinos go through our bodies every second. I don't know if a neutrino can pass through a neutron, I would like to know. Anyway, what is the average number of collisions and/or passages thru per second? How many per 15 minutes? (I'm wondering if the were actually around 1 per hour, chance could distort the measurement of neutron half-life, provided the neutrino could somehow initiate neutron decay. Thanks, Rich Peterson155.97.8.213 (talk) 20:52, 25 March 2016 (UTC)

Well 10¹⁵ solar neutrinos pass through every square meter in one second. A neutron is about 10^-18 meters across so it covers about 10^-36 square meters. So it'll take on average 10²¹ seconds for a neutron to be hit by a neutrino - the age of the universe is around 10¹⁸ - so there is about a one in a thousand chance for a particular neutron here on earth to EVER be hit by a solar neutrino. Of course there are a lot of neutrons out there - so this does happen - but it's not happening enough to make much of a dent in the neutron half-life. SteveBaker (talk) 21:13, 25 March 2016 (UTC)

Your neutron diameter is way off. According to the article it has a mean square radius of 0.8×10⁻¹⁵ m, which corresponds to a cross-sectional area of 2×10⁻³⁰ m². So it's more like one neutrino every 20 million years (using the flux value from Solar neutrino#Observed data, which is close to yours). But individual neutrinos are probably not localized enough to definitely pass through or not pass through a neutron, so it might be better to say there's a constant neutrino flux through every neutron that adds up to 1 particle every 20 million years. Also, that's the number that pass through the neutron, not the number that hit it (i.e., interact with it). For the latter you'd have to use the interaction cross section instead of the size of the neutrino (see below). -- BenRG (talk) 02:01, 26 March 2016 (UTC)

good answer155.97.8.213 (talk) 00:05, 26 March 2016 (UTC)

Neutrinos don't "pass through" neutrons. Neutrinos pass through ordinary matter most of the time because neutrinos only interact through the weak interaction and gravity. Gravity is so weak that it has basically no effect at the atomic level. The weak interaction has an extremely short range. If a neutrino gets close enough to a neutron or another weakly interacting particle, they will interact. But neutrinos usually go right through the Earth without noticing because atoms are mostly empty space, so they rarely get close enough to any particle to interact. It's like firing a BB gun and trying to hit an individual grain of sand. When neutrinos do strike a particle, they interact and produce other particles, which we can detect in neutrino detectors. This just happens so rarely that we need to build huge detectors to get a decent detection rate. Remember, everything at the quantum level is tiny and weird. Our ape brains aren't intuitively programmed to understand it. --71.110.8.102 (talk) 21:19, 25 March 2016 (UTC)

Neutrinos do pass through neutrons. The cross-sectional area of a neutron is ~10⁻²⁶ cm², and according to this page, the cross section for neutrino-neutron interaction is around 10⁻³⁸ cm²/GeV. So a neutrino will pass through about a trillion neutrons before interacting with one. -- BenRG (talk) 02:01, 26 March 2016 (UTC)

thanks155.97.8.213 (talk) 00:05, 26 March 2016 (UTC)

What is the relation between axon and its etymology?

What is the relation between axon and its etymology? according to what I read, the meaning of "axon" is axis in Greek. My question is what is the relation between axis to the part of the neuron which is called axon. 93.126.95.68 (talk) 22:54, 25 March 2016 (UTC)

The entire nerve is an "axon". An axis on a graph is a line - perhaps "axon" refers to the line-like shape of a nerve. DrChrissy ^(talk) 23:05, 25 March 2016 (UTC)

Thank you93.126.95.68 (talk) 23:29, 25 March 2016 (UTC)

In other, uh, words, while both words are derived from the same Greek root word, their meanings in modern English differ: cf. axis and axon. --71.110.8.102 (talk) 01:30, 26 March 2016 (UTC)

The axon was definitely discovered by Camillo Golgi, probably in the late 1870s or early 1880s, but I can find no evidence he ever called it an axon. Merriam Webster's dictionary says the word "axon" was first used to describe a part of a neuron sometime in the 1890s, which could plausibly make the name an invention of Santiago Ramon y Cajal, though I have been unable to find the first publication to use the word. I'm able to find a publication titled "Neuron" in 1896 by one Aloysius Kelly that defines an axon as the "axis-cylinder", and just a year later, everyone seems to be throwing around the word "axon" as if you are expected to know what it means. Someguy1221 (talk) 04:36, 26 March 2016 (UTC)

what is meta-sympathetic system?

I always knew about the sympathetic and para sympathetic systems, and today I was told about the meta-sympathetic system, but I didn't understand well the man who told me about it and I didn't find enough or reliable information about this system, and if it's accepted in the scientific world or it's arguable. 93.126.95.68 (talk) 23:29, 25 March 2016 (UTC)

"Metasympathetic nervous system" seems to be a phrase peculiar to a handful of Russian scientists. Based on this translated abstract, it is something entirely different from the sympathetic and parasympathetic systems, but I have no access to their paper (not that I'd be able to read it unless it's translated into English). It's a bit unlikely that there is a feature of anatomy only Russians are aware of, so this has to be either something English-speaking scientists give a totally different name, or a pile of bullshit. Maybe someone can find their paper and let us know. Someguy1221 (talk) 04:39, 26 March 2016 (UTC)

Yes, it makes sense. 1) Indeed, the man is Russian scientist but his English wasn't so clear for me. 2) The most of the result about it i PubMed are from Russian. 3) your suggesting for the two possibilities are absolutely reasonable, and in any case I don't think that this term is studied in the universities in US for example. The classical method is to teach about 2 systems only (sympathetic and Para-sympathetic). Anyway, It will be useful to see article about this topic. 93.126.95.68 (talk) 05:19, 26 March 2016 (UTC)