Wikipedia:Reference desk/Archives/Science/2010 September 10

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September 10

Remote controlled almost self-replicating small production systems.

Has there been any practical experiments with self-replicating machines using mostly “bulk” material?

Large-scale space-activity require production in space since the launch cost from earth is so high. Before large-scale production in space is implemented it is extremely expensive to have a human workforce in space. Production should therefore be remote controlled or automatic.

The current global industrial complex is able to replicate itself and to a large extent automated but it is way to complex and big to be a god model for something to send to the moon, asteroids or the moons of Mars. Most of the work on self-replicating machines seems to be either theoretical or using prefabricated parts. I would be interested in attempts to build machines that can replicate most of its mass from bulk material, parts that are hard to build such as semiconductor chips will of curse need to be prefabricated. I know that we don't have the technology to build self-replicating machines that uses raw material such as lunar-regolith but machines that uses simpler bulk material such as plastic granulate is an important step.

I find the RepRap-project interesting but limited since it is built mostly of prefabricated steel bars and need to be mounted manually. Are there similar research projects that are more ambitious and professional? Have they build functioning prototypes?

I have read Self-replicating machine and Clanking replicator Gr8xoz (talk) 00:23, 10 September 2010 (UTC)

Based on your interests, you might find this old Soviet SF short story interesting: Crabs on the Island, Masked Booby (talk) 01:30, 10 September 2010 (UTC)

I havent had time yet to reed it but it sounds intresting thank you for the link.Gr8xoz (talk) 11:43, 10 September 2010 (UTC)

I don't know whether you can say the RepRap isn't 'ambitious'. Their goal is indeed that most (well theoretically all, but I think most would acknowledge that's a very far off dream) of the machine be self-replicatible i.e. the number of 'vitamins' be kept to a minimum. And there is the Kartik M. Gada prize that's been offered related to the RepRap [1] which requires, amongst other things, 90% of the volume be printable. (See for example [2] one of the projects which is aiming to eventually meet the requirements of the prize.) Note that one of the goals of many developers for the RepRap includes work on making printed circuit boards and perhaps even assembling the boards via some sort of pick and place technique. However it's true they're centred on low cost and earth usage so some self assembly isn't usually seen as a big deal provided it's something most people can do without needing much training or experience, but I don't think you can say this isn't ambitious, they just have a different goal from what you're looking for. In particular, building or assembling something that is the same size as the device building it raises several issues potentially requiring the device is capable of moving by itself rather then occupying a fixed space and building something that requires no human involvement requires a very high degree of reliability or otherwise the internal ability to fix problems that arise (even the KMG prize allows one printer head jam to be fixed) and a resonably consistent degree of built quality. Of course being ambitious doesn't mean you don't recognise the limitations you currently face, hence why the RepRap team is concentrating on building something that works and then improving it until it can make most of itself. Nil Einne (talk) 07:11, 10 September 2010 (UTC)

I was more looking at the current prototype than the overall project goal. A useful self-replicating system in space need of curse be able to move it self or it's offspring any way to avoid crowding. I did not rule out human intervention but the intervention should be performed by remote control. A robotic arm on wheels produced by the RepRap system would be an interesting step towards self assembly.Gr8xoz (talk) 11:43, 10 September 2010 (UTC)

pimelea linifolia......flax leafed riceflower;

does this plant normally be pink? i have two pink ones but i thought they were only white.i am 67 and have never before seen pink. i know there is pink in a different riceflower but this is the flax leafed riceflower & the other is a more rounded leaf. i live on the midcoast, n.s.w. australia02:23, 10 September 2010 (UTC) —Preceding unsigned comment added by 123.208.80.32 (talk)

Our article on Pimelea linifolia says that the flowers are white, but this says that there is a subspecies which can have pink flowers. Smartse (talk) 12:36, 10 September 2010 (UTC)

Polar night and midnight sun

According to the Barrow, Alaska article, the polar night lasts for about 65 days, while the midnight sun lasts for 82 or 83 days. Why are these durations not the same? —Bkell (talk) 02:31, 10 September 2010 (UTC)

The article polar night gives a clue "but in regions that are located at the inner border of the polar circles where midnight sun is experienced, this is not true. Because of twilight, these regions experience polar twilight instead of the polar night. In fact, polar regions typically get more twilight throughout the year than equatorial regions." This implies that "twilight", when the disc of the sun is below the horizon but where the suns light is still detectable, do not count as "night". However, midnight sun must be when the disc of the sun is actually visible. The other 18 days of the year must be times when the sun is just below the horizon; that is not actually visible, but too bright to be considered "night". --Jayron32 03:26, 10 September 2010 (UTC)

See also atmospheric refraction, which makes the sun appear higher over the horizon than it would in a vacuum. PhGustaf (talk) 03:32, 10 September 2010 (UTC)

I thought about atmospheric refraction, but I didn't think it alone could be responsible for that 18-day difference. The discrepancy in the definitions, as Jayron pointed out, seems to be a likely explanation; I hadn't thought of that. Thanks. —Bkell (talk) 03:46, 10 September 2010 (UTC)

In addition to the points mentioned, the Earth is nearer to the Sun during the Northern Hemisphere winter, so it is a few days shorter than the Northern Hemisphere summer. --Anonymous, 03:55 UTC, September 10, 2010.

(edit conflict) Those aren't the only reasons. The Earth's orbit is not a perfect circle, but an ellipse, so, at some points during the year, the Earth is closer to the Sun than others. When is the Earth closest to the Sun? About January 3, right in the middle of Northern hemisphere winter. Now when the Earth is (very slightly) closer to the Sun, it is moving slightly faster around its orbit, a bit like an ice skater who pulls in his/her arms to spin faster. You can see this as well in the dates of the equinoxes: there are about 186 days between the Spring Equinox and the Autumn Equinox, but only about 179 days between the Autumn Equinox and the Spring Equinox. Physchim62 (talk) 03:58, 10 September 2010 (UTC)

One would expect the polar night and polar day to be the same length only if the sun was a point source of light (instead of a circle of about 30 arc-minutes or so), and if the atmosphere did not distort light slightly like it does. I would anticipate that the polar night length and the polar day length would be the same on Pluto if it had the same orbital eccentricity and orbital inclination assuming Pluto has seasons. Googlemeister (talk) 13:02, 10 September 2010 (UTC)

Also, when the Sun is exactly at the horizon, approximately half of its disk is above the horizon, making it bright enough (barring any mountains) to be considered "24-hour sun" if the disk does not go entirely below the horizon. Considering this alone, there would be more days with 24-hour sun than 24-hour darkness. ~AH1^(TCU) 01:20, 12 September 2010 (UTC)

What type of Machine Gun

I vaguely remember a type of Machine Gun I saw long ago. It was one of those type that are kept on ground on a tripod etc. The ammunition is fed by a magazine inserted from above (like most non-portable types). The peculiar thing about this was the fact that when you fire, the trigger-hand handle you are holding moves backword several inches (and the gunner has to keep his elbow-joint supple enough to accommodate the jerk !) Why would they build such a thing ? Does this mean that the gunner has to be ready to have his hand move at least a dozen times per second (when set on rapid fire mode !)  Jon Ascton  (talk) 06:42, 10 September 2010 (UTC)

The only thing I can think of is the woeful French Chauchat light machine gun, where the whole barrel assembly moves (although that is bipod mounted). I believe most tripod mounted weapons are belt-fed rather than having a magazine. You could have a look at this[3] site and see if anything rings a bell. Let us know if you find it! Alansplodge (talk) 18:45, 10 September 2010 (UTC)

I'm not too specific on "tripod", it may have been on a bipod as well (please note "etc"). Yes, I know of models where barrel moves back, but what I am talking about is the hand-grip moving back. I know it sounds weird...

Indoor heating in Florida

Hello, I would like to know at about what winter isotherm does indoor heating start to become common in Florida? Or in the Southern U.S., for that matter. I know that in Southern Florida, around Miami, most people only have small one-room heaters they take out occasionally in January, but I have no idea if the winter temperatures in the rest of Florida warrant a need for indoor heating during most of the winter months. This is my guess, but I imagine Northern Florida would definitely need indoor heating during all the winter months, every year. In general, at about what isotherm or latitude do homes and buildings in the Southern U.S. need indoor heating? Thanks 201.21.183.191 (talk) 12:45, 10 September 2010 (UTC)

This map shows the average 60° isobar in January. Vulnerable people will likely turn on the heating if the temperature drops much below that. Rojomoke (talk) 14:37, 10 September 2010 (UTC)

*Isotherm. Isobars mark pressure. —Preceding unsigned comment added by 92.11.0.210 (talk) 09:37, 12 September 2010 (UTC)

It's only the southernmost part of Florida (Miami and the Keys), which has a subtropical climate, where winter heating *might* be optional - but of course, all that depends on how cool is "cold" to you, and the normal variations of weather. Being a native Southerner, and having lived all over the place from Miami to Atlanta to Texas and in between, I can tell you that people in North Florida definitely run the central heating unit on most days of the winter. Pull up the "climate" section of the wiki article on any major Florida city and notice the temperature chart for the winter months. You live anywhere north of extreme south Florida, and you definitely need regular heating in winter.

Having said that, it's also true that anywhere in the Deep South, say from the latitude of Atlanta or Dallas southward, we *might* actually need to run the air conditioner on any given day of the year, including mid-winter: it's quite normal and routine to get some very warm days (high 70's, even 80's) even in January and February, every year. And then a week or a day later, it might dip down to the 30's or below, and you're running the heat again. That's normal Southern weather. Textorus (talk) 02:16, 15 September 2010 (UTC)

Carrots

I head a long time ago, that drinking excessive amounts of carrot juice could turn someones skin orange. Is that true? Does wiki have an article on it? —Preceding unsigned comment added by Biskyhigh (talk • contribs) 13:47, 10 September 2010 (UTC)

See Carotenosis. --Chemicalinterest (talk) 13:49, 10 September 2010 (UTC)

It's worth noting that the colour of the vegetable has nothing to do with the colour your skin turns. Green vegetables like cabbage can produce the same effect and you don't turn green, you go yellow. Regards, --—Cyclonenim | Chat  14:43, 10 September 2010 (UTC)

Manganese as a free element

Is manganese really found as a free element? It is quite reactive and readily corrodes. I know in some meteorites it may be found, but those are not very common, IIRC. --Chemicalinterest (talk) 14:14, 10 September 2010 (UTC)

The "Occurrence and production" section deals with this Quadrupedaldiprotodont (talk) 14:17, 10 September 2010 (UTC)

Some finds of native manganese have been reported [4], but it is hardly very common. Physchim62 (talk) 14:59, 10 September 2010 (UTC)

PANCREATIC CANCER AND GENOMICS RESEARCH

MY HUSBAND DIED TO PANCREATIC CANCER AND I AM CONCERNED FOR MY CHILDREN AND GRANDCHILDREN. I HAVE RECEIVED INFORMATION FROM NATIONAL FOUNDATION FOR CANCER RESEARCH THAT A DR VON HOFFHAS IDENTIFIED SEVERAL GENETIC WEAKNESSES IN PANCREATIC CELLS. IS THERE ANY WAY THAT MY CHILDREN AND GRANDCHILDREN COULD BE TESTED TO SEE IF THE ARE PREDISPOSED TO THIS DREDFUL DISEASE? I LOOK FORWARD TO HEARING FROM YOU. THANK YOU. —Preceding unsigned comment added by 65.32.133.7 (talk) 15:12, 10 September 2010 (UTC)

Asking a doctor would be a better choice. Most of us are not doctors and might give you bad advice. --Chemicalinterest (talk) 15:26, 10 September 2010 (UTC)

In fact, Wikipedia policy forbids us to give medical advice on the Reference Desks. Looie496 (talk) 15:32, 10 September 2010 (UTC)

It is true that we here on the reference desks can't really answer your question adequately. However, your doctor may not know the answer, either. For the most up-to-date information about genetic risk for cancer, you could look for an MD or genetic counselor who specializes in clinical cancer genetics; this person will know what genetic tests are available and applicable to your family's situation. You can ask your doctor for a referral to a genetics specialist (either MD or genetic counselor). Alternatively, you can search for a nearby genetics clinic here or find a genetic counselor here. --- Medical geneticist (talk) 16:34, 10 September 2010 (UTC)

Wireless USBto

I am planing to buy and use it in India, Warpia, which is a Wireless USB Audio and Video Display adopter set.According to Wikipedia," Wireless USB is based on the WiMedia Alliance's Ultra- WideBand (UWB) common Radio Platform,Which is capable of sending 480 Mbit/s at a distance up to 3 meters and 110 Mbit/s at up to 10 meters. It was designed to operate in 3.1 to 10.6 GHz frequency range, although local regulatory policies may restrict the legal range for any given country". Would this device be compatible in India?Jayessandhu (talk) 17:36, 10 September 2010 (UTC)

muscles shaking

When an athlete finishes a grueling day at the gym, or after a marathon or weightlifting competition, their muscles are often shaky including what might look like shivering. Is this because their muscle has used up its stores of acetylcholine(sp)? Googlemeister (talk) 18:47, 10 September 2010 (UTC)

No, acetylcholine is essentially 'recycled' by your body, at least in the immediate short term. There's a good written explanation here. Regards, --—Cyclonenim | Chat  19:06, 10 September 2010 (UTC)

Your link says it is because certain chemicals produced by the neural motor units can't keep up with demand. That is what I thought, but what specific chemicals? Googlemeister (talk) 19:43, 10 September 2010 (UTC)

I was always under the impression that you don't exhaust acetylcholine, at least not after exercise as it should restore itself with time. Perhaps I'm wrong, or the shakiness is a symptom that occurs until acetylcholine supply recovers. I'll leave this to someone else! Regards, --—Cyclonenim | Chat  19:55, 10 September 2010 (UTC)

The technical term for this seems to be fasciculation. Googling "Fasciculation after exercise" got this link [www.ehow.com/how_5276858_understand-muscle-twitching-after-exercise.html] (which is 'blacklisted' by WP!. The Scientific American link is interesting, but note it is dated 1999 so may well have been made obsolete by newer research, though it sounds quite logical and technically correct. And it does seem they are speaking of acetylcholine.
Calcium is also used in triggering the contraction of muscle fibres (see Sarcomere). I'm wondering if there might be circumstances where it may actually not be a depletion, but an excess of Epinephrine/Adrenaline ? Hope this helps, 220.101 talk^\Contribs 09:01, 11 September 2010 (UTC)

Methane Toxicity

I read an article a couple of days ago (sorry, don't have a link) about a town in Pennsylvania where the ground water was flammable due to the large amount of methane dissolved in it, which the townsfolk blamed on nearby fraking operations. Obviously flammable water presents some large problems, but would it be harmful to drink it (supposing that the only "abnormal" chemical in it were methane)? The methane article seems to deal only with respiration, not ingestion. 96.246.59.38 (talk) 19:32, 10 September 2010 (UTC)

I assume it was a story like this, according to Methane#Potential health effects it shouldn't be dangerous to drink. The water itself can't be flammable though, its the gas that escapes from it that is. If methane is getting into the water, it's likely that other compounds that might be toxic also are though. Smartse (talk) 22:14, 10 September 2010 (UTC)

Very tasty hydrogen sulfide is normally found in methane deposits. --Chemicalinterest (talk) 00:29, 11 September 2010 (UTC)

Wth? Methane is not nearly soluble enough in water to make water flammable. Note that most low-proof alcoholic drinks do not ignite -- and their concentrations are much higher than you would find CH4 in a high-dielectric solvent. John Riemann Soong (talk) 06:07, 11 September 2010 (UTC)

On the other hand H2S has a decent solubility in water -- around 7g/kg during the winter time. John Riemann Soong (talk) 15:14, 11 September 2010 (UTC)

The only way I can think of for methane in water to be flammable is for it to be methane ice. It could potentially be dangerous if significant released methane or carbon tetrachloride(?) from the water in the stomach somehow got into the lungs or if fire swallowing was performed in the presence of the gas. ~AH1^(TCU) 01:12, 12 September 2010 (UTC)

It definitely does happen: [5], as well as an awesome Youtube video: [6]. I don't think the methane is dissolved in the water, but rather flows as bubbles along with the water in the pipes. Buddy431 (talk) 03:00, 12 September 2010 (UTC)

Strength not linked to muscle size?

I'm quite a small guy, 5' 10", slim build, moderately fit.

Recently I discovered that I am stronger than a friend of mine who is 6' 1", weighs 11 stone and has visibly large muscles. What's going on here? He's also moderately fit.--92.251.241.196 (talk) 20:01, 10 September 2010 (UTC)

Two thoughts come to mind : 1) Your friend was being nice, or 2) You chose a 'test of strength' that did not test his 'visibly large muscles' but instead some other muscles that he never works out. APL (talk) 20:49, 10 September 2010 (UTC)

Well as the "test" was a physical fight and we were both angry I think neither of those hold true. He was trying to hit me but was doing no damage, and I pushed him back against a wall and held him, he was also trying to hold his ground but couldn't--178.167.172.73 (talk) 21:41, 10 September 2010 (UTC)

Another thought. I am very thin but someone else that has arms about twice as big beats me in arm-wrestling, but not easily. I can tell he is trying to, so it is not a matter of being nice. I think if muscles are not worked out, sometimes they can stay large but deteriorate internally, and sometimes get replaced by fat. --Chemicalinterest (talk) 21:06, 10 September 2010 (UTC)

Go look at professional athletes like runners. You don't see huge thighs, you see quite thin legs with very lean muscle. Size isn't everything! Regards, --—Cyclonenim | Chat  22:41, 10 September 2010 (UTC)

178.167 - fighting is hugely technique based: a professional Flyweight boxer doesn't weigh that much and isn't that big but I suspect their superior technique would mean they'd have little trouble disposing of someone (lacking the same training) twice their build in a regulation boxing match. Basically size and build are probably correlated with strength but are by no means a guarantee of. ny156uk (talk) 23:00, 10 September 2010 (UTC)

If all else is equal, muscular strength should be proportional to cross sectional area of the muscles, see Muscle_strength#Strength. Also Skeletal muscle. Genetics plays a part of course, you may have more 'fast twitch' muscle fibres allowing quicker application of force. See "Genetic variation in muscular strength" from the British Journal of Sports Medicine - 220.101 talk^\Contribs 09:17, 11 September 2010 (UTC)

The strength (and maybe placement?) of your tendons and ligaments would also make a difference. As would the amount of fat vs protein in your muscles. A 'cushioning' of fat in the muscle fibres increases strength which is one reason why bodybuilders look 'buff' but aren't as strong as strongmen. If your friend works out in order to increase muscle mass he won't increase strength in the same way that somebody who trains for strength would do. Also consider that he may be a 'gentle giant'... even if you're angry he may not consider you a threat. Spoonfulsofsheep (talk) 20:34, 11 September 2010 (UTC)

Pivoting during a strike or hold usually increases the force applied. And for the non-British, one stone = 6.35 kg or 14 pounds. ~AH1^(TCU) 01:01, 12 September 2010 (UTC)

tornado army tank

Is it possible for a tornado too pick up an army tank would it take EF5/F5 status too gain lift. --86.41.129.119 (talk) 20:49, 10 September 2010 (UTC)

An M1A2 tank weighs around 60-70 tons or so and an F5 has had a maximum wind speed of 300 mph. I suspect it would move the tank, but I am skeptical about it picking it up. I wonder if any photos exist of a tornado moving a bulldozer or similar, which might give an indication. Googlemeister (talk) 20:57, 10 September 2010 (UTC)

I did watch storm chasers on the discovery channel and they made a vehicle thats allot like a tank except they had too use something too prevent it from being uplifted so they can go into one but an average tank has nothing like that. --86.41.129.119 (talk) 21:12, 10 September 2010 (UTC)

The vehicles on Storm Chasers aren't truly comparable to a tank in any fashion. I can't imagine they'd top out at more than 5 tons or so; an average tank wouldn't need additional leverage. — Lomn 21:29, 10 September 2010 (UTC)

They could maybe drag it horizontally but there would be no chance of lifting it. Not even a C-130 Herculese or CH-47 Chinook can do that.--178.167.172.73 (talk) 21:56, 10 September 2010 (UTC)

C-130 Hercules is the link you want. Buddy431 (talk) 00:55, 11 September 2010 (UTC)

There is at leas anecdotal evidence of tornadoes being able to lift railroad cars [7], or [8], or [9], for example, but railroad cars are significantly larger, and somewhat lighter than a tank, so that makes the job easier. It's also unclear whether the cars are truly lifted, or rather just pushed off the tracks (still an impressive feat; see this Youtube video [10]. It's interesting that the engine, presumably significantly heavier, manages to stay upright). It also appears that this question has been asked elsewhere, with the general consensus being "no, probably not" ([11], [12], [13], [14]). While none of those sites approach being a reliable source, the comments seem quite reasonable to me. Train cars can be pushed over (and maybe lifted) because they have big sides. Tanks do not. Buddy431 (talk) 01:10, 11 September 2010 (UTC)

One TV account of a southern US tornado said it removed a concrete slab covering a storm cellar. I expect that a strong US tornado might well pick up and whirl around and crash to earth an Abrams tank. There are relatively few Abrams tanks per square mile, so the probability of empirical confirmation of the hypothesis is slight. Instead, do the analysis of a force 5 tornado versus the aerodynamics of the said tank. Could it in principle lift/launch the tank? Edison (talk) 04:40, 11 September 2010 (UTC)

For the sake of a simplified upper bound on what a tornado could lift, consider the following. Suppose the EF5 tornado has a max wind speed of 350 km / hr (100 m/s). Further suppose those winds are somehow capable of blowing directly upward from underneath the tank (very unlikely in practice, but that's why this is an upper bound). The maximum force such winds would impart is of order ${1 \over 2}\rho Av^{2}$ where v is the windspeed, ρ is the air density, and A is the surface area underneath the tank. Taking an M1 Abrams as a representative tank, A is ~30 m^2. For a force of 150000 Newtons, which implies an ability to lift an object up to ~15 tonnes. This is of course well under the 60 tonnes of the tank. So, even given an ideal flow geometry, it is probably impossible for a EF5 to lift a tank. Dragons flight (talk) 06:59, 11 September 2010 (UTC)

They is a big flaw in that as tornado maybe able too do considerable damage from the debris it carries and also it may rip the armor off or the wheels. debris like a 2X4 may get impaled through the armor due too how fast it travels and could shut the engine down or cause the tank too go on fire. Also if the Tornado manages too rip armor off it would be considerable lighter perhaps be more likely also the tornado may have poles, trees, fridges or vehicles like cars or maybe even trucks being whirled around very fast and they gain more energy so they could destroy the tank rather then lift. —Preceding unsigned comment added by 213.94.238.147 (talk) 16:00, 11 September 2010 (UTC)

• Antitank slugs and rockets travel fast too. A 2x4 in a tornado is probably slower, about 200 mph.
• Ripping armor off? The armor is so strong that just a little wind shouldn't rip it off.
• Very few tornadoes produce enough energy to hurl trucks around.

In conclusion, tanks are made to withstand blows stronger than a tornado gives. --Chemicalinterest (talk) 19:54, 11 September 2010 (UTC)

Tanks are not made too withstand a tornado, a EF5 would be able too lift the a truck, the armor is strong enough too withstand little wind, but winds going 350km (an EF5 windspeed) is not little its very strong winds. A 2x4 is not the only thing in a tornado a car or fridges might also be fast enough. --213.94.238.147 (talk) 21:14, 11 September 2010 (UTC)

You could throw cars at a tank all day long and it wouldn't penetrate the armour. They're made to resist ATGMs. A Tornado could do nothing to a tank except damage the extreior systems, tracks and gun. The crew compartment would remain intact and would stay on the ground.--92.251.228.27 (talk) 23:55, 11 September 2010 (UTC)

Debris in the tornado flying in excess of 300 mph would increase any damage done to a tank. These speeds are enough for wooden planks to penetrate concrete. ~AH1^(TCU) 00:55, 12 September 2010 (UTC)

As I said before, antitank slugs travel faster than 300 mph and are stronger than a plank. Probably the penetration of the concrete by the plank is because of the shock which deforms the crystalline structure of the concrete. --Chemicalinterest (talk) 18:46, 12 September 2010 (UTC)

Tanks are made to resist streams of molten metal travelling many times the speed of sound. Debris going 300 mph shouldn't even scratch it.--178.167.229.75 (talk) 19:05, 12 September 2010 (UTC)

The debris as it goes 300mph gains enough energy too possibly penetrate armor of a tank a anti tank slugs mabe faster and stronger but thats just if someone had thrown a plank at a tank a EF5 tornado is amazing possibly even more powerful and strong then a tank and therefore it would possibly easily pick up the tank at some height and smash it back down with considerable force making some bits and pieces break off and therefore the tank become aswell as massive debris it won't be just one 2X4 if you look at the 1999 may oklahoma footage you can see all the debris from that tornado not just 2X4 but things like fridges, cars, trucks, trees these are just normal everyday items are turned into missles and eventually weaken the armor somewhat enough too be blown off and the tornado might atleast kill the driver of the tank. IMO nothing is safe from a EF5 tornado --83.70.106.193 (talk) 20:10, 12 September 2010 (UTC)

Is a ditch 30 feet deep ripped in the ground by an EF5 tornado? If it is, then I will admit that a tank can be ruined by a tornado. Some dirt should be able to be ripped up more easily than thick steel armor. --Chemicalinterest (talk) 20:34, 12 September 2010 (UTC)

During the 1991 Persian Gulf War, an M1A2 tank took a direct frontal hit from a T-72 with the armor remaining intact. A projectile fired from a T-72 has an initial velocity of roughly 3,000 miles an hour, and is more dense then pine. Now, while a 2x4 can do some pretty interesting things when traveling at 300 mph, I don't think it is in the same league as a tank shell when it comes to penetrating power. Googlemeister (talk) 13:35, 13 September 2010 (UTC)

2x4 are not the only debris there are also things like cars, trucks, fridges and other stuff being whirled at 300mph would atleast do some bit of damage perhaps even enough too weaken the armor so that be whipped off and more debris end up damaging the tank from inside also it won't be just be 1 2X4 or 1 car they be allot more then 1 kind of thing in a tornado going into a urban or city area and also i have seen footage of a EF5 tornado actually ripping a house from its foundations. --86.41.130.206 (talk) 17:36, 13 September 2010 (UTC)

What happened to Ron Gellatley ?

Ron Gellatley is an Australian naturopath/medical herbalist/homeopath who wrote a book called 'How to Fight Prostrate Cancer and Win' first published in 1998 when he was in his seventies which apart from the obvious had all sorts of information about herbs and what they do. I'm wondering where he is now as I can't find ANY information about him.121.73.185.217 (talk) 21:03, 10 September 2010 (UTC)

Did you try google? You might want to read this before though. Smartse (talk) 22:01, 10 September 2010 (UTC)

?Prostate cancer

He got shut down. Well I'm just guessing. John Riemann Soong (talk) 15:16, 11 September 2010 (UTC)

Conflicting reactions

The reactions listed at this and manganese(VII) oxide conflict. The specific reaction is the one with concentrated sulfuric acid. The first article says that it produces ozone as a "special" product. The second article says it produces manganese(VII) oxide with some left over ozone. Why do not the two reactions coordinate? Thank you. --Chemicalinterest (talk) 21:26, 10 September 2010 (UTC)

The two descriptions seem coherent enough to me: it's one of those reactions which is "messy", you don't really want to try to write a balanced equation for it, but the products are Mn₂O₇ and ozone, for as long as either of those species stay around. The exact yields of each product will depend on the exact conditions. Physchim62 (talk) 23:35, 10 September 2010 (UTC)

The one in potassium permanganate does not list the very dangerous manganese(VII) oxide formation in the reaction. --Chemicalinterest (talk) 00:27, 11 September 2010 (UTC)

I've tweaked the wording to make it clearer that you can't make ozone by this route without also making manganese heptoxide. Physchim62 (talk) 00:51, 11 September 2010 (UTC)

does Vitamin C increase or decrease the strength of the immune system?

The immune system depends on reactive oxygen species to fight bacteria...so will constantly elevated bloodstream levels of Vitamin C neutralise ROS's? John Riemann Soong (talk) 23:01, 10 September 2010 (UTC)

Have you read Vitamin_C#Immune_system? Rojomoke (talk) 23:43, 10 September 2010 (UTC)

Also relevent, Vitamin C megadosage (a therapy promoted by none other than Linus Pauling) and Megavitamin therapy. --Jayron32 01:45, 11 September 2010 (UTC)

Eating lots of fruit and vegetables is good for you, and includes many other micro-nutrients as well as Vitamin C, but artificially high doses of Vitamin C can cause kidney stones as I know from painful personal experience. 92.29.119.29 (talk) 16:40, 11 September 2010 (UTC)

Also take a look at Antioxidant if you haven't already. Constantly elevated levels of anything would be fatal eventually i think though! Spoonfulsofsheep (talk) 20:55, 11 September 2010 (UTC)

I'm not totally alien to the concept of biochemical redox reactions. My question is -- what prevents high levels of cytoplasmic Vitamin C from annihilating ROSs?

I'm also curious about "paradoxical" interactions; oxidative stress can cause loss in connections between epithelial cells as cells try to "protect" themselves and shut down intercellular connections, but administering hydrogen peroxide at 200 micromolar in a primary astrocyte culture apparently stimulates bridgebuilding by promoting F-actin polymerisation. wtf? John Riemann Soong (talk) 02:57, 12 September 2010 (UTC)

It sounds as if you are closer to the leading edge of research in this area than most of us here at the reference desk. Experts seem to regularly argue, and sometimes change their minds about the effectiveness of high levels of many vitamins. Dbfirs 14:18, 13 September 2010 (UTC)