Wikipedia:Reference desk/Archives/Science/2012 January 19

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January 19

What was "opening medicine"?

I heard an Australian author on the radio today talking about her books, based around the life of her convict ancestor, William Wiseman. She asked the audience if anyone knew what 'opening medicine' was. There were groans and laughs from the audience and she asked those in the know to explain, on the quiet and if they felt they could, to the others. In her book it is a treament for worms in children. Could you find this out please? — Preceding unsigned comment added by 137.92.97.212 (talk) 03:18, 18 January 2012 (UTC)

A medical book from the 1840's used "opening medicine" to describe laxatives. (The editor formerly known as Edison). BnBH (talk) 05:13, 19 January 2012 (UTC)

In other words, "that opens the bowels" (OED).--Shantavira|^{feed me} 11:45, 19 January 2012 (UTC)

superconducters

what is the value of resistance offered by superconducters connected in parallel? (0/0,1/0,0) — Preceding unsigned comment added by Sanoy samuel (talk • contribs) 05:51, 19 January 2012 (UTC)

It will be very small, approaching zero for ideal superconductors. You can solve this analytically by applying L'Hôpital's rule to the parallel resistor equation, with R1 and R2 each approaching zero for ideal superconductors. Nimur (talk) 06:15, 19 January 2012 (UTC)

$\lim _{(R_{1},R_{2})\to (0^{+},0^{+})}{1 \over 1/R_{1}+1/R_{2}}=0.$ -- ToE 06:21, 19 January 2012 (UTC)

Blot (biology)

Was the term 'blot' in use for laboratory techniques before the invention of the Southern blot method? --NorwegianBlue ^talk 08:52, 19 January 2012 (UTC)

The OED seems to imply that the use of "blot" as a means of recording proteins onto film doesn't show up until Southern blot. Browsing around results in JSTOR for "blot" in biological journals doesn't seem to bring up any consistent technical usage of the term prior to Southern blot. The place to really look is where the term "Southern blot" comes from. (I know the inventor's name is Southern, but did he call it a "blot" or did others coin the term?) It's not in the original paper by Southern linked to in the article; the only use of "blot" is the sentence: "After the appropriate period, strips are removed from the solution or paraffin oil, blotted between sheets of filter paper and washed, with stirring, for 20 to 30 min in a large volume of the hybridization solvent at the hybridization temperature." The usage of blotting paper seems responsible for the term. I can't help but wonder if it was influenced by the Rorschach inkblot. This isn't meant to be a conclusive answer, just what I was able to come up with. There doesn't seem to be much out there on the history of the Southern blot, unfortunately. It would make for an interesting historical study in the proliferation of laboratory techniques. --Mr.98 (talk) 19:27, 19 January 2012 (UTC)

Nice answer. I'll only add that, publishing his work in 1975, Southern was likely fairly familiar with blotting paper, so that "oil, blotted between sheets" wouldn't need any additional referents. SemanticMantis (talk) 20:05, 19 January 2012 (UTC)

Also, blotter paper is used in thin layer chromatography, which was developed in the 1940s, according to History_of_chromatography#Thin_layer_chromatography. So, if biologists were using TLC in the 1960s, they may well have been using "blot" in a similar context before the Southern blot technique was invented. SemanticMantis (talk) 20:13, 19 January 2012 (UTC)

Thanks a lot, both! I've just received the 1975 paper from my library, which confirms that Edwin Southern didn't use the word 'blot' as a noun at all, only as a verb, and only in the sentence that Mr.98 quotes. I really liked the reference to the Rorschach blot, which predates the Southern blot by half a century! Blotting paper indeed must be the origin of the term. Although blotting paper is used in chromatography, I've never heard the term 'blot' being used to describe a chromatogram. I think the reason is that in Southern/Northern/Western/etc blots, the action occurs somewhere else (gel electrophoresis), and the separated mixture of biological substances in transferred -- blotted --- onto blotting paper. In chromatograpy, however, the separation occurs in the filter paper itself, and there is no blotting step. --NorwegianBlue ^talk 21:45, 19 January 2012 (UTC)

Evolution again...

Well, this time I want to ask about two things I can't relate about genes and evolution.I can't relate the "all or none" nature of genes and how they work, and the smooth, gradual nature of evolution(or even smooth differences between individuals, which can be explained easier by considering the large number of genes...or can it?).I mean in cases like evolutionary arms race for example, it's often said that for example, lions become faster as the zebras become faster.What does this "getting faster" mean in genetic terms.I mean genes don't get "amplified".Does each little level of getting faster require a different genetic change?

Also is this right to say that when the environment doesn't change in a long time, some traits in species tend to be exaggerated?(please don't sacrifice any of my questions for the other, this is the last level for me to get a satisfying picture of how evolution works, or maybe one of the last ones!)

Last question: is it true that chromosomes only form during cell division?--Irrational number (talk) 15:56, 19 January 2012 (UTC)

For question 1) it isn't exactly clear that genes (DNA) are the ONLY thing which affects evolution, there are also epigenetic factors, research in this field is somewhat nascent, but there is considerable evidence that some heritable characteristics can be passed outside of nucleic acids. Also, there is not universal agreement among the scientific community that evolution is constant and gradual. There are two competing theories on the rate of evolution (and, as always, reality probably lies somewhere between them). The kind of evolution you are talking about is called phyletic gradualism, while the competing theory, which says that evolution occurs in fits and starts, is called punctuated equilibrium. Both ideas are probably at work in evolution. The reason lions and zebras both get faster has to do with natural selection: in a very broad sense lions that are too slow to eat zebras starve to death and thus don't get to have slow babies to pass their slow genes onto, while zebras that are too slow to avoid lions don't get to have slow babies to pass their slow genes onto. For your last question, yes, the actual "chromosome" structure you recognize in the pictures only forms during certain phases in the cells lifetime. At many times, the individual chromosomes aren't visually identifiable, see Chromatin which has some nice descriptions on the various forms it takes. The chromasome structure most people will recognize seems to happen during the metaphase part of the cell's life cycle. --Jayron32 16:40, 19 January 2012 (UTC)

On the very first part of your question regarding the 'all-or-nothing' 'present-or-not' nature of genes, you may want to have a look at our article on gene expression. Getting from a particular DNA sequence to a visible trait is a multistep process that can be tweaked all the way along by a pretty huge number of factors. There are some very complex mechanisms that regulate the effects of single genes. (If you think about it, your own body is a powerful demonstration of this. Trillions of cells with the same DNA, yet some of those cells are germ-hunting macrophages that can engulf and eat bacteria; some are two-meter-long neurons that can electrically link your brain to your toes with a single cell; some are hair-making trichocytes that spin out nothing but fibers all day long. If you were to separate out all these different cell types and look at them in a petri dish, you'd have no idea they all came from the same organism—yet their genes are identical.) TenOfAllTrades(talk) 16:59, 19 January 2012 (UTC)

hm... I had the very question that "why are the cells in my body different when they are genetically identical" here in refdesk...--Irrational number (talk) 17:12, 19 January 2012 (UTC)

(edit conflict)x2 Well we obviously can't enumerate which genes (and proteins, etc.) specifically make modern lions and zebras faster than their ancestors, but the overall genetic change meant they are phenotypically expressed to make the animals faster. It doesn't necessarily mean it has to be the same gene again and again, as genes aren't usually that discrete (e.g. there is no "fast gene"), but sometimes it does.

The evolutionary arms race is best explained by the Red Queen's Hypothesis. The name comes from Red Queen's race in Lewis Carroll's Through the Looking-Glass, from a conversation between Alice and the Red Queen:

"Well, in our country," said Alice, still panting a little, "you'd generally get to somewhere else — if you run very fast for a long time, as we've been doing."

"A slow sort of country!" said the Queen. "Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!"

Imagine that species (or even different sexes in a species) are constantly in a coevolutionary arms race to outwit the other. As soon as one overtakes the other in weapons/skill/reproductive potential, the other must adapt or die. A classic example would be the extreme toxicity of the rough-skinned newt (Taricha granulosa). Why is it so poisonous when only a tenth of its poison could already kill a full-grown man? The answer lies in its predator - the common garter snake (Thamnophis sirtalis). The snakes continuously adapt to the toxins of the newts so they can eat them. In turn, newts continue to become more poisonous so they can avoid being eaten. Snakes who have lesser resistance to tetrodotoxin die and thus only the snakes with the strongest resistances pass their genes to the next generation. Newts with less lethal poison get eaten, so only the more poisonous pass on their genes to the next generation. Each drives the other's adaptations, and in turn, evolution, until you end up with newts with extreme amounts of poison and snakes with extraordinary resistance to that poison due to the positive feedback. To an outsider species not part of the coevolution, the adaptations of the two seem too much; but to both species, they are simply maintaining the status quo. The number of newts getting eaten and the number of snakes dying is probably the same as when the two first began their predator-prey relationship (hence "running to stay in the same place").

And yes, the rate of evolution is still unclear but it may be both gradual and slow over long periods of time, or rapid in short bursts.

As for the second question, not necessarily. Isolation can induce allopatric speciation usually through genetic drift, and different environments induce different evolutionary pressures. The longer an organism is in a certain environment, the degree into which it has evolved to fit that environment is usually greater. Not always though, some environments can exert enough different evolutionary pressure to keep organisms always "on their toes" so to speak, so it could readily adapt to new environments. Some have limited effect such that the organisms begin to "forget" their former "malleability". Instead, their evolution is focused on exploiting the environment they are in as best as they possibly can; with the disadvantage that if the environment were to abruptly change or if they find themselves in another environment, they would be more vulnerable (e.g. whales have adapted so much to life on the sea that beaching them will mean death).

And your last question is a bit vague. If you meant the formation of genetic material, see mitosis and meiosis. Chromosomes are DNA. They divide and reorganize during these phases, but they do not form out of nothing. If you meant the visible clumped chromosomes (chromatin), refer to Jayron's answer above.-- Obsidi♠n Soul 17:40, 19 January 2012 (UTC)

Getting faster is a goal, not a means; it has no one implementation in genetic terms. Some aspects are trade-offs, for example fast twitch muscle fibers versus slow twitch depend on whether your wildebeest has to run away from a sprinting predator or one which can sustain speed for a longer period. I think that the attachment of tendons to the bone should have something to do with it; they can be designed to apply better leverage to improve strength, at the cost of slowing the speed at which the joint actually moves, just like different gears on a car transmission. Wnt (talk) 08:29, 22 January 2012 (UTC)

Your question touches on something I've wondered about: to what degree is the existence of a prey species dependent on the predator? We all know the story of the dodo - without predators to keep it in shape, it was just waiting for the first thing to come along and wipe it out. I wonder whether evolution, acting on large populations over a long time scale, might punish populations of zebras that become too fast for the lions to catch just as effectively as it punishes individuals that fail to keep up. Wnt (talk) 08:32, 22 January 2012 (UTC)

Genetically engineering healthy foods

So far genetic engineering has been done to benefit farmers, but not consumers (except perhaps by lowering price). For example, crops have been engineered to be either disease or parasite resistant, or to better tolerate pesticides. Now my questions:

1) Is anyone working on genetically engineering foods to actually be healthier (or perhaps to make healthy foods more palatable) ?

2) For a specific example, could chicken eggs be engineered to have more good cholesterol and less bad cholesterol ? StuRat (talk) 18:27, 19 January 2012 (UTC)

1) See golden rice. Also, I would not say that GMO crops that increase yield "benefit farmers, but not consumers". Independent of price, genetic engineering, as well as "traditional" techniques of hybrid crops and artificial selection, have dramatically increased worldwide food production over the past ~50 years, effectively increasing the carrying capacity of Earth. SemanticMantis (talk) 19:20, 19 January 2012 (UTC)

The infamous Flavr Savr was clearly intended to be appealing to consumers even if it failed. In addition to what SM has said, note that disease and parasite resistance, and in some cases even better tolerance of pesticides may benefit consumers in ways besides yield. For example by reducing the amount of pesticides that have to be used, or allowing the use of potentially less dangerous pesticides (in the case of pesticide tolerance). (In a more roundabout fashion, they may in some cases reduce environmental damage which is likely to be a benefit to consumers living near the farmers and perhaps even some further away. And remember with the carrying capacity/yield thing, it not only means you can support more people at a lower price, but for a given number of people use less land.) I expect the controversy of GMOs means that there's less incentive for more obvious benefits to consumers. If your product is healthier or more palatable, you're likely going to need to label it as such. And when you label it, some people will start to ask why and will quickly find out it's from a GMO. Nil Einne (talk) 05:07, 20 January 2012 (UTC)

But the problem is people's perceptions of GMO foods. If there was something demonstrably healthier, like the egg I mentioned, perhaps this would overcome people's reluctance to embrace the "unknown". Specifically, something "improved" that actually shows up on the nutrition label. StuRat (talk) 05:14, 20 January 2012 (UTC)

That's a nice theory. When you're spending millions of dollars developing, marketing etc a GMO however, you have to live in the real world where your theory could easily fall flat on its face, particularly in Europe. Nil Einne (talk) 15:54, 20 January 2012 (UTC)

That's my point exactly, GMO foods without any obvious consumer benefit have fallen flat in Europe, so it's time they try something else. StuRat (talk) 16:02, 20 January 2012 (UTC)

2) From the looks of it, egg cholesterol can be modified simply with drugs or diet, which is probably cheaper. The fact we haven't been able to breed low-cholesterol chickens also implies that so far we have no way knowing which genes are responible for egg cholesterol levels. It does seem at least theoretically possible - chickens produce more cholesterol than their embryoes need, so GM chickens would still be able to breed. Smurrayinchester 09:54, 20 January 2012 (UTC)

Benefit to farmers, but not consumers? Norman Borlaug is often credited with saving over a billion people worldwide from starvation (he used multiple techniques, not just GE food). Von Restorff (talk) 12:32, 20 January 2012 (UTC)

To clarify, I mean obvious benefits to those consumers who can freely choose between GMO and non-GMO foods. This doesn't apply to those in third world nations, who will eat any food they can get, even if it glows. To some extent, it doesn't apply in the US, where GMO foods are not labelled as such. However, some consumers will still find out which brands use GMOs and avoid them. Europe is probably the biggest market where consumer perception of the value of GMOs is critical. StuRat (talk) 16:06, 20 January 2012 (UTC)

• Point of clarification / mincing words: GMO crops are often designed to be herbicide resistant, e.g. Roundup Ready soybeans, or to be pest resistant, e.g. Bt corn. Pest resistant crops may allow for lower or less use of pesticides. In contrast, pesticide tolerance is not a normal goal of GMO crop design. Commonly used pesticides, even the most noxious (e.g. Sevin), don't harm the conventional crops they are applied to. SemanticMantis (talk) 15:35, 20 January 2012 (UTC)

See pesticide. Herbicides are a class of pesticides. You're correct herbicides are by and large the only pesticides for which tolerance is engineered in plants (for obvious reasons). Nil Einne (talk) 15:44, 20 January 2012 (UTC)

Duly noted, thanks. Now I'll start correcting my weed science associates when the get sloppy with terminology ;) SemanticMantis (talk) 16:16, 20 January 2012 (UTC)

Genetically_modified_tomato#Improved_nutrition lists a couple of examples. SmartSE (talk) 17:23, 20 January 2012 (UTC)

Note that LDL and HDL are defined by the human protein constituents that interact with the cholesterol and other lipid materials during the period when they pass through the bloodstream. A chicken egg contains neither, and can't control what the body will do with ingested cholesterol unless it acts more or less like a drug (say, if you added statins to them...). Reducing the cholesterol content of an egg would be complicated, because the egg by its nature needs to produce a whole chick's worth of cell membranes quite rapidly. Of course, as biology is flexible, I'm sure you could reduce it by some significant amount. In the extreme instance I suppose you could design an egg to respond to some external stimulus by destroying its stored cholesterol, which would not be provided to eggs for breeding. Wnt (talk) 08:23, 22 January 2012 (UTC)

Why is it easier to make an electric car than it is to make an electric airplane?

^Topic ScienceApe (talk) 20:28, 19 January 2012 (UTC)

Weight of the batteries. AndyTheGrump (talk) 20:32, 19 January 2012 (UTC)

... Rather, energy density of the batteries. Avgas contains some 100x more energy per kilogram than a lithium ion battery. Nimur (talk) 20:40, 19 January 2012 (UTC)

Yup, strictly speaking, you're right. Plus, using Avgas, the plane gets lighter as you use it up - so you need less power, which makes it even more efficient. AndyTheGrump (talk) 21:28, 19 January 2012 (UTC)

Note that it's not being electric that's a problem for airplanes, it's storing the electricity. Solar-powered electric motor airplanes do have some potential, in the form of an unmanned, light-weight, observation platform. StuRat (talk) 04:16, 20 January 2012 (UTC)

Induced gamma emission may be of tangential interest: among the potential applications is powering electrical airplanes. 157.193.175.207 (talk) 09:11, 20 January 2012 (UTC)

And to state the obvious, but that completes the answer to the questions: The car has all 4 wheels continuously touching the ground which supports it, so the weight is less of an issue (although it is still a bit of an issue).--Lgriot (talk) 09:13, 20 January 2012 (UTC)

There are a couple of battery electric aircraft in development, such as the Sonex ESA and an electric version of the Pipistrel Panthera. The problems encountered are a very short range and aircraft endurance (by modern standards). With a normal engine (and a typical fuel system) these aircraft would far outpace themselves in terms of performance. The electric Panthera is intended to have a range of 215nm (400km), per the company website, and sacrifices two of the four seats to accommodate the batteries. The all gasoline version is intended to do 1,000nm for comparison. I personally think that battery powered aircraft technology will creep into the market and become somewhat popular, if for no other reason than with prices often at $5 a gallon or more for AvGas in the United States (and therefore probably much more elsewhere), many of us simply cannot afford to fly a lot of the gasoline powered aircraft very much anymore. For local sport-type flying, I suspect that the electric aircraft would cut down on the costs tremendously (after initial purchase). Falconus^{p t c} 20:04, 20 January 2012 (UTC)

You seem to be saying that the cost per mile is less in a battery-powered airplane. I'm rather skeptical. Battery powered cars are more expensive per mile, when you prorate the much higher cost over the life of the vehicle (or life of the batteries). It would be even worse for airplanes, because of the inefficiency in carrying all that extra weight around (and fewer passengers, in your example). I'd say fuel prices would have to go up far more for batteries to be cheaper, and, even then, alternatives like ethanol or compressed hydrogen would probably replace fossil fuels. StuRat (talk) 08:39, 21 January 2012 (UTC)

If I put 100,000 miles on a Nissan Leaf, by my rough calculations (figuring 34,000Kw for 100,000mi), which is when the warranty runs out, I would spend $3,060 on electricity, assuming 9¢ per kW. In the same number of miles, for a vehicle that gets 30mpg, I would burn 3,333.33 gallons of gas. At $3.50 per gallon, that's $11,6667 $11,667. In the US, it is more cost effective to get a standard car, as new batteries currently cost Nissan $18,000 a pop. However, in England, where fuel costs €1.58/L, or €5.98/gal ($7.75/gal). There, the fuel costs for that same distance would be $25,833.33. Assuming electric costs of 15p per kW, that would be £5,100, or $7,942.23. That means that in effect, in England (if my calculations are correct), you would only spend $118 more per 100,000mi assuming a battery life of 100,000 miles. With improvements in technology, rising gas prices, less maintenance (if I am not mistaken, motors are more reliable, are they not?), and the fact that the battery life is probably quite a bit more than the 100,000 guaranteed miles (a car company would be insane to put that guarantee on it while predicting that it will die at 101,000), I think it probably would in fact be be cheaper (if not significantly so) in places such as England, at least without including the initial purchase costs. Maybe I am missing some factors, however. Airplanes are a different beast, and I do not have the numbers, nor time to research them at the moment. You may be correct that at the moment the new technology would be much more expensive, even after the initial purchase. I assumed it was far cheaper, but the car demonstrates that even that doesn't break even yet in the US. Does my math look right there? Falconus^{p t c} 14:17, 21 January 2012 (UTC)

Looks roughly right, with a few caveats:

1) Your "$11,6667" seems to have acquired an extra digit, but I don't think you carried that through to the subsequent calcs.

2) Many batteries are able to hold progressively less charge as they get old. Not sure if this applies to electric car batteries or not. However, if so, they might very well only replace "bad batteries" when they no longer hold any charge at all, or an absurdly low charge, so one needs to read the fine print to determine what this 100,000 mile warranty actually covers.

3) Batteries also lose charge when sitting still, so some accounting for that is needed.

4) The higher costs of gasoline/petrol in England is due to some rather stiff taxes, and there may also be subsidies in the cost of the electric vehicle. Whether those should be figured in is debatable. If we're trying to determine which is generically the most efficient technology, then perhaps taxes and subsidies should be removed from the calcs. If we are including them, then we need to also consider future changes. While taxes on gasoline and subsidies for electric vehicles may make sense when trying to encourage a new industry (and discourage the old one), that picture would change if the majority switched to electric vehicles. In particular, the gasoline taxes may no longer be sufficient for road maintenance, etc., when gasoline sales start to drop off, and governments may no longer be able to afford to subsidize electric vehicles once sales reach tens of millions. So, inevitably taxes will be shifted from gasoline to electric vehicles at some point. Is this likely to happen within the 100K mile test period ? Hard to say. Then there's the cost of disposing of the batteries once they fail. Who will pay for this ?

5) The gasoline-electric hybrid seems to be a better bet, as it doesn't need to have so much battery capacity to have a reasonable range. Maybe our calcs should include those.

6) You said "...I think it probably would in fact be be cheaper (if not significantly so) in places such as England, at least without including the initial purchase costs". However, I see no justification for excluding the initial purchase price. StuRat (talk) 18:40, 21 January 2012 (UTC)

Captain Obvious to the rescue: cars in general are easier to make than airplanes, and we have much more experience researching, developing and building cars. @StuRat: Gasoline-electric hybrid airplanes may be a good idea, but hybrid cars suck. Von Restorff (talk) 19:06, 21 January 2012 (UTC)

Just to update on the UK situation, your price for electricity was a little on the high side. Average cost for a 'unit' is about 13p (1 unit = 1kWh), although this can be reduced to 4.5p/unit if you have an Economy 7 tariff and charge your car at night. Also, a grant of 25% of the purchase price of an electric car (up to a maximum grant of £5000) is given by the government. See here. I realise this doesn't help to answer the original question, but I hope it helps in the accuracy of the comparison. - Cucumber Mike (talk) 19:23, 21 January 2012 (UTC)

Okay, thanks; that should then drastically decrease the electricity costs for England to £1,530, or $2,382.67 at the 4.5p/kW rate, giving a difference of $23,450.66. That would be $5450.66 left over after the $18,000 battery. I also found this. Nissan is saying that once the battery capacity dips below 80%, people should start replacing individual cells, not the whole pack. Granted, at some point by default you will have replaced the whole battery, one cell at a time, so I'm not sure if/how that helps in the long run (unless the cost of the unit itself, without the actual cells, is significant), but that kind of relates to question number two. As for the hybrid aircraft, there will also be the hybrid Pipistrel Panthera, with performance figures between the electric and the gasoline versions. The thing to be seen is how the technology develops in the future; how much the prices will come down, and what the eventual disposal costs will be, as StuRat said. Although, apparently some people are looking into reusing the batteries in other applications that don't require the 80% charge capacity to be useful, thus extending the battery life (and meaning that the battery/cells would still have some value when it's time to switch them). Falconus^{p t c} 20:07, 21 January 2012 (UTC)

My reading on that link is that they won't do anything about weak batteries until they drop below 80%, and then will just replace enough cells to bring it back up to 80%. So, you should probably figure on 80% of the stated range as the real range, further limiting it's usefulness. StuRat (talk) 04:29, 23 January 2012 (UTC)

Photosynthesis Poster

Hello. Where can I buy a poster of photosynthesis appropriate for university? I prefer a supplier that can deliver to Canada. Thanks in advance. --Mayfare (talk) 20:55, 19 January 2012 (UTC)

My first reaction was Fisher Scientific, fishersci.com - where I found this photosynthesis poster. You'll have to decide if it's appropriately detailed; there are a few other items - lab kits, CD ROMs, and so on. Nimur (talk) 21:07, 19 January 2012 (UTC)

As a supplement, there are nice graphics in our article on Photosynthesis as well (more in Commons:Category:Photosynthesis). You can print them freely (and even sell them), with the only requirement being that you provide attribution to the artist(s).-- Obsidi♠n Soul 21:38, 19 January 2012 (UTC)

Several of those charts are not in English. If you need assistance translating or modifying them, you can post a request for translation here on the reference desk, or on WP:TRANSLATE. Nimur (talk) 01:36, 20 January 2012 (UTC)

Forging a ring from fountain pens

I'm into forging a ring from iridium-platinum (or iridium-osmium) tips of fountain pens (according to some sites, 30-40 tips for one ring is sufficient). The idea is to melt those tips in a form and then cool the alloy down. Is there a relatively simple and cheap device to create the appropriate melting temperature? I'm also concerned about the proper way of cooling, thanks. --46.204.99.30 (talk) 22:46, 19 January 2012 (UTC)

Not being funny but I think you'd be better off finding some other to do. The time taken to achieves this, would make it more economical to use other sources of platinum. The pen tips have only enough plating to ensure that one has a non corrosive tip which will allow ink to flow smoothly to the paper. Your sources may be misleading you. --Aspro (talk) 23:14, 19 January 2012 (UTC)

Iridium, platinum, and osmium all melt quite a bit hotter than any steel you've ever worked. Are you a skilled metallurgist? Do you have a furnace? High temperature crucible? Oxy torch? No, there is no way to do this on the cheap-and-easy. This article seems to be a pretty good overview. Nimur (talk) 03:26, 20 January 2012 (UTC)

In which U.S. states are capybaras legal?

In which U.S. states are capybaras legal as pets? I'm hoping for a link that will show all states instead of having to go to each state individually. Thanks, 72Dino (talk) 23:53, 19 January 2012 (UTC)

In urban areas of the Southern U.S. (like Houston and New Orleans especially) you can find nutria living in drainage ditches and sewers and the like. Nutria are very similar to capybara, so perhaps if you hang out with some of the homeless in New Orleans, one will just come along and decide to be your pet. No need to import yet another invasive giant rodent into the U.S. One is enough, thanks. --Jayron32 01:50, 20 January 2012 (UTC)

However I'm guessing if you're Catholic, you can't eat your pet nutria during lent if the urge ever arises. Nil Einne (talk) 05:13, 20 January 2012 (UTC)

This page has a summary on laws about exotic animals in each state. None of them specifically mention capybaras.

Many states ban or place severe restrictions on "inherently dangerous animals" (Virginia), "potentially dangerous animals" (Connecticut), etc, laws which are sufficiently flexible that they might apply to capybaras. However, many of these laws have grandfathering provisions, so if you had a capybara for long enough you could keep it.

Realistically if an animal is sufficiently unusual, a state may never have considered if it should be allowed. Most states have a State Veterinarian who will answer questions on this sort of thing. --Colapeninsula (talk) 12:43, 20 January 2012 (UTC)

crazy

No medical advice. See talk page.
The following discussion has been closed. Please do not modify it.
how do i know that im not crazy? I cant remember where i learned it but i know crazy people doesnt know their condition, so what assurance do i have that everything i see and does is normal? — Preceding unsigned comment added by Arah18 (talk • contribs) 23:57, 19 January 2012 (UTC) Anosognosia (an unawareness of one's condition) is common with some mental illnesses, but certainly not all of them. The way to find out if you yourself have a mental illness is to ask a psychiatrist. Red Act (talk) 00:08, 20 January 2012 (UTC) If I show you a proof that you are not crazy, would it help? How could you know that you are judging the validity of the proof correctly? Looie496 (talk) 00:54, 20 January 2012 (UTC) OP here, Thats exactly whats bugging me. What if that psychiatrist is just a creation of my craziness. MahAdik usap 01:31, 20 January 2012 (UTC) Are you able to function reasonably well in society? ←Baseball Bugs What's up, Doc? carrots→ 02:11, 20 January 2012 (UTC) "Craziness" is a qualitative label, mental illnesses are conditions while fitting into society is something different altogether. Many people hold the opinion that those with mental conditions simply need a bit more adaptation to fit into places such as work settings. [1] ~AH1 (discuss!) 03:11, 20 January 2012 (UTC) Depends on the mental condition, I would attest. I've known people with mental conditions that basically allowed them to do absolutely nothing — not even really survive — without heavy duty medication. I'm sure there are a lot of mental conditions which are just on the spectrum of "functional" but there are lots that are quite clearly physiological dysfunction, and I don't have a lot of truck with folks who would deny this fairly obvious fact for ideological reasons. There are experiments one can do to confirm that a tiny chemical change can make a huge difference in one's perceptions of reality. --Mr.98 (talk) 03:16, 20 January 2012 (UTC) Assuming this is meant philosophically and not psychiatrically, this is not too different from the famous question asked by Descartes: How do you know you are not dreaming? Or put another way, how do you know you're not just a brain in a vat? What if life is nothing but a simulation? There isn't any great answer to this, to be honest. If you assume that your ability to distinguish reality from fantasy is totally inhibited, then anything's up for grabs. Descartes thought he thought, therefore he was, but even that's not as iron-clad as he made it out to be. In the end, I fear, you just have to do your best, and try to be aware of your own limitations. But there's zero guarantee that you'll be assessing reality correctly. Alas. But this is not medical advice, and should you suspect that you indeed are suffering from mental illness, seeking out a professional is a good idea, even if you fear that professional only exists in your head. It's better than nothing. --Mr.98 (talk) 03:16, 20 January 2012 (UTC) This is a fantastic question! I think people who are really delusional often get very upset when someone calls them crazy, they are 100% certain they are NOT crazy and take great offense at the suggestion. If instead you have not 100% ruled out the possibility you might be a bit nuts and are willing to genuinely question this with honest introspection, in an on going "sanity checking" process, I think that is actually a decent sign that you aren't totally nuts. In the end, I think it is probably impossible to know for certain, solipsism is a related article. Vespine (talk) 03:35, 20 January 2012 (UTC)

If you are interested in pursuing this question from a purely philosophical viewpoint, feel free to repost it on the Humanities desk and make it clear that you are referring to something abstract, not any actual diagnosis of mental illness. If you are actually wondering if you are suffering from mental illness, please consult a professional: we cannot give medical advice on the Reference Desk. --Mr.98 (talk) 22:13, 20 January 2012 (UTC)