Wikipedia:Reference desk/Archives/Science/2014 December 3

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December 3

rephrasing of my question

I hope i'm not being disruptive by asking this question again,but what are the chances of catching the hpv virus for a man who performs oral sex on a woman? Secondly, once a man is exposed to the virus orally, what is the probability that he will develop oral cancer? I'm just rephrasing my question.199.119.235.132 (talk) 00:38, 3 December 2014 (UTC)

Surely one of these articles will lead you in the right direction. That would at least be a good start on your research. You may also want to try Google Scholar, which will limit your searches to peer-reviewed research journals. --Jayron32 03:31, 3 December 2014 (UTC)

You know this question is linked to the one i just asked. It's further up in the pageWhereismylunch (talk) 03:44, 3 December 2014 (UTC)

What about the probability of developing oral cancer once you are exposed orally to the virus? — Preceding unsigned comment added by Whereismylunch (talk • contribs) 05:35, 3 December 2014 (UTC)

Drivers of diesels who have to park in the cold

Do any of them try to arrive home with as empty a tank as possible, then add enough hot diesel (with a funnel) to last until the engine/fuel system is cold again? I don't know what temperature of diesel is safe to do this with (120F? More?) or how cold this would work at but it's probably better than nothing right? Would this still work if your trip was so short that you only put a cup (quarter liter) of hot thermal mass in and the entire car is at thermal equilibrium with -25F or something? No, I don't drive or go to minus Fahrenheit places - I'm not in any personal danger from answers given here. Sagittarian Milky Way (talk) 01:13, 3 December 2014 (UTC)

Also I'm not sure if this would work if the trip was so long that the fuel in the tank would have enough time to cool to the filter clog point, if that would happen. Sagittarian Milky Way (talk) 01:17, 3 December 2014 (UTC)

I've never heard of this method. It might keep the fuel in the tank warm longer, but the engine is where the real problem with cold lies (since the engine block is a much larger component of the total thermal mass than the fuel inside it at any given time). Glow plugs, or simply leaving the vehicle running, or at least starting it every so often, are other methods which are used in an attempt to keep engines operating in extreme cold environments. StuRat (talk) 02:26, 3 December 2014 (UTC)

I'm thinking of, uh, redneck-type people who won't pay for a heated garage, to tell the truth. To clarify, I hadn't thought of leaving the tank full, I meant pouring only enough at cold starts to probably not run out of gas before the next break in driving that's long enough for it to get cold. (you could always pull over and add a bit more if you added too little). This would minimize diluting the hot diesel with cold diesel. I'm assuming that it would not cool so much that it couldn't be started and the heat of a running vehicle might keep the fuel filter unclogged as long as the fuel added is not very little cause they wouldn't sell a diesel with much too high filter clog temperature for that location. Sagittarian Milky Way (talk) 04:15, 3 December 2014 (UTC)

In climates where diesel is likely to freeze, block heaters are used extensively. People use them on gasoline cars as well to keep engine coolant and lubrication working as well. You'll find many people in cold climates plugging in their heaters at night when they park at home so the engine will start in the morning. --Jayron32 04:20, 3 December 2014 (UTC)

Certainly sounds safer to me than those drivers I've seen with fires under their trucks to warm them up so the engine will start! I thought they were warming up the fuel tank rather than the engine. But who am I to judge. The thing I would worry about if I was driving about where it could get very cold is that there was a way for me to stay warm for some hours or a day if the weather got so bad the road got blocked. Dmcq (talk) 09:28, 3 December 2014 (UTC)

As always, Wikipedia has an article that answers these questions.Winter diesel fuel.--Aspro (talk) 23:41, 3 December 2014 (UTC)

I used to work in Resolute Bay. There they don't turn off pickup truck engines between September and May. I mean they don't turn them off *at all*.93.74.189.242 (talk) 16:41, 7 December 2014 (UTC)

People with knowledge in Organic chemistry \ Symphatomimetic amines

Please see Talk:Phenethylamine/Archive 1#What_are_.22Low_dosages.22_of_PEA.3F_-_A_problem_with_the_second_passage_of_the_article. Regards, Ben-Natan (talk) 01:22, 3 December 2014 (UTC)

gemstone questions

where online I can buy a faceted smoky phantom quartz pendant? The link I show is just an example but it is just clear quartz in the photo. http://www.bestamericanarts.com/Susan-Goodwin-Faceted-Quartz-Pendant Not smokey quartz. Is a green Grossular garnet and wiluite/viluite the same stone? Where online can I buy a pendant with blue vesuvianite or green Garnet in it? Thank you! Venustar84 (talk) 01:34, 3 December 2014 (UTC)

Your best bet may be to visit a local jeweler who can do custom work. My wife's wedding ring is custom made, and was not all that more expensive than an "off the rack" ring with a similar-sized stone and ring would have been. If you visit a good local jeweler who does custom pieces, you can commission just about anything you want; if you have a piece that you already like, but merely want a different stone it's a fairly easy thing to switch out the stones. --Jayron32 03:29, 3 December 2014 (UTC)

For years, Gary's Gem Garden, 404 Marlton Pike E, Cherry Hill, NJ, ‎(856) 795-5077 ‎garysgemgarden.com had an egg-sized 500ct flawless cut smoky quartz, unset, but I would just have carried it in my pocket like an egg. (I am not sure what "phantom"specifies in the OP's question.) He does commission work depending on the materials. He can also be extremely rude to customers and staff according to personal observation and on-line reviews, but that doesn't seem to affect his work. It's where I'd go. BTW, the going price for that jewel was $1/ct. and it sold about 10 years ago. μηδείς (talk) 04:54, 3 December 2014 (UTC)

How long would Lake Erie have to be before Buffalo's climate gets less snow?

What about Lake Ontario's east coast? That lake is further north where it's colder and doesn't point south of west so it should have more of a buffer before the water-warmed air rises above freezing. Lake Ontario and Michigan don't freeze much anymore because of global warming so if you made them longer they should eventually warm the Canadian air above freezing often enough to counter the extra water vapor, no? If it's near 100% humidity on the eastern shores already then maybe more length wouldn't enhance the snowfall much anyway. Sagittarian Milky Way (talk) 02:23, 3 December 2014 (UTC)

You'll want to read the article on lake effect snow. It explains the process pretty well. Otherwise the Wikipedia reference desk does not engage in idle speculation. You should read the disclaimers at the top. --Jayron32 03:25, 3 December 2014 (UTC)

Well essentially the question is approximated by "how much distance is needed to turn a continental air mass to a maritime one?" What do you want me to do?, ask "at what point would more fetch (the term in the lake effect article) decrease snow instead of increasing it" to sound less like idle speculation? There are many variables, azimuth, latitude, the shape of the continent upwind of it, where the mountains are, how tall are them, is the upwind ocean only a few hundred miles wide?, thousands? Is that side of the equator maritime and mild like our current Southern Hemisphere? Is there even land above 45°N? (like there probably wasn't in the past)? That's too open-ended. N. American/Asian sea-effect snow doesn't even reach France or Oregon. It's a mild maritime winter. The cold is clearly snuffed out of existence. Eastern Great Lake shores are still considered to have a continental climate, though, but less cold than it would be if the lakes were land. What's in between? A meteorology buff who knew temperature, humidity, snowfall.. of the Atlantic at those latitudes could probably give an educated guess, so an answer that's not wild speculation is possible. Sagittarian Milky Way (talk) 03:53, 4 December 2014 (UTC)

Also, someone once asked how they would do astrology on Mars when a human mission is not even planned yet and nobody complained about violating the rules on speculation. Sagittarian Milky Way (talk) 04:43, 4 December 2014 (UTC)

Is the Adrenaline agonist while in the same time it's antagonist too?

What is the main difference between antagonist to antidote? 149.78.231.106 (talk) 05:36, 3 December 2014 (UTC)

An antagonist is a character in a drama. An antidote is a treatment for a poison. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:36, 3 December 2014 (UTC)

Not false, but incomplete and it this case, not helpful. See Receptor antagonist (both of you ;-). An antagonist can be an antidote, but not all antidotes are antagonists, and not all antagonists are antidotes. --Stephan Schulz (talk) 08:38, 3 December 2014 (UTC)

Can I get an example for both the options? 10:22, 3 December 2014 (UTC) — Preceding unsigned comment added by 149.78.231.106 (talk)

Antivenoms are examples of antidotes that work by using immune cells to break down the poisonous proteins in the venom, not by inhibiting any particular receptor. And I don't think Beta blockers are ever given as antidotes to any particular poisons. --Stephan Schulz (talk) 10:46, 3 December 2014 (UTC)

• A drug that works as an antagonist fits in a receptor where a normal chemical would fit and produce a normal effect, yet the antagonist does not produce that effect, and competes therefore with the normal agonist. An antidote is any chemical, which by any means, counteracts a toxin (this can be broadened biologically to include vaccines and some diseases). Some toxins act by attaching to receptors, not "letting go", and providing an overstimulus, such as various nerve agents. In such a case, timely administration of an antagonist might prevent the toxin from overloading all the receptors, but that's gong to be a hugely tricky strategy based on the original dose and time of the toxin received, and the relative kinetics of the toxin-hyper-agonist and the antagonist, i.e., how long they each remain active. Finally, certain toxins are actually antagonists themselves, especially those that cause paralysis, like botox and curare. They bind to and block receptors necessary for muscle contraction, without actually allowing the muscles to contract. μηδείς (talk) 21:26, 3 December 2014 (UTC)

How do I make a perfect cup of hot cocoa?

Hot chocolate usually comes in powder form. In my experience, there is always some undissolved powder at the bottom. How do I minimize or eliminate the undissolved remaining powder in order to make the perfect cup of hot chocolate? By the way, is hot cocoa a solution or colloidal suspension? 140.254.70.33 (talk) 18:09, 3 December 2014 (UTC)

The first step is to make a slurry in the bottom of the cup. Add a small amount of hot water and stir that glop very vigorously. Add a bit more water and stir again, but more gently. Then fill the cup to your desired level and stir gently. That will ensure that the mix is as thoroughly incorporated as it can be, but the stuff will come out of suspension again if you let it sit. Two other quick tips: 1) make your own cocoa mix; it literally is just as easy as the pre-mix your get, but tastes better. 2) add a small amount of cayenne powder to the mix. Too much will make it bitter, but a small amount will increase the "chocolaty-ness." Matt Deres (talk) 18:36, 3 December 2014 (UTC)

I find using an electric mixer is fast and produces great results. I use a single-beater handheld mixer for this.

ETA: hot chocolate is an emulsion or colloidal suspension of cocoa solids in water/milk. Mihaister (talk) 18:46, 3 December 2014 (UTC)

Any ground up/roasted plant material is going to be a really complicated substance - I would be extremely surprised if 100% of it was an insoluble suspension or if 100% of it was dissolved - it's almost certainly a mix of the two. SteveBaker (talk) 19:28, 3 December 2014 (UTC)

• Google "perfect hot cocoa". μηδείς (talk) 03:03, 4 December 2014 (UTC)

Mix the cocoa and the sugar first, when dry. This makes it much easier to mix with water. (And if there are any solids left they will at least taste good, but that's not the goal.) Secondly try making hot chocolate instead of hot cocoa - use dark chocolate chips, melt them in a small pot with hot water and milk, you won't need extra sugar. Ariel. (talk) 09:08, 4 December 2014 (UTC)

Shape of the continents

Why do the continents become narrower as you go south? — Preceding unsigned comment added by 143.254.218.246 (talk) 19:41, 3 December 2014 (UTC)

There is no widely accepted theory. See Continental drip and the talk page for some more info. Matt Deres (talk) 19:49, 3 December 2014 (UTC)

Not specifically a reason, but they were all originally clumped together into Pangea. Later, they separated into Gondwana and Laurasia. The articles have some pictures that show how the tapered portions lined up long ago. So one explanation is that that's the way the cookie crumbled [1]. SemanticMantis (talk) 20:02, 3 December 2014 (UTC)

Indeed, it seems like the majority of this "drip" is the three-way split from one end of Gondwana, with South America, the tip of Africa, and the Antarctic Peninsula all converging to a single point. (of course, the Peninsula now faces north, which makes it the 'exception that proves the rule' so to speak) Apparently this point is part of where Gondwana came together 550 million years ago, and the site of breakup from 180-110 million years ago. Whether coincidentally or not, the tip of Florida and the tip of India are sort of lined up toward that central point. So it seems like a genuine and interesting question. The article draws a connection of the separation of India with the Réunion hotspot and Deccan Traps, but that was considerably later than the original three-way split. I wonder where that hotspot was 130 MYA and whether it had anything to do with the breakup... a pity I know so little about this! Wnt (talk) 22:25, 3 December 2014 (UTC)

Things that expand or contact often break open into three. Four is too much, two is too few. Most arid cracked earth cracks into shapes with three lines meeting don't they? Sagittarian Milky Way (talk) 06:24, 4 December 2014 (UTC)

@Sagittarian Milky Way: I don't know about "most", but Patterned ground and Mud Cracks can indeed have degree 4 vertices, and it's at least not very rare if not exactly common. Some pictures in our articles show this and you can find many more on google images, including rectangles, hexagons, and other irregular patterns including lots of degree 4. I do agree that 5 and higher is fairly rare, but it could be achieved in a suffficiently controlled experiment. This all depends on the granularity of the substance, the moisture, the thickness, and how fast it dries. I highly recommend anyone with an interest to mix up a few trays of mud and see the different types of pattern that can develop. You can also read up on the surprisingly sophisticated math necessary to understand the pattern formation, e.g. here [2]. A more empirical approach is given here [3], and a more applied approach here [4]. The pattern formation processes are much stronger on the scales of mud cracking than they are for continental breakup, but I'm not really sure why. Also the driving forces (hots spots vs. dessication or freeze/thaw) are rather different. SemanticMantis (talk) 16:07, 4 December 2014 (UTC)

So I was not too right, but I think I read that new mid-oceanic ridges always form when the crust expands (of course it doesn't literally expand but separates and New stuff is added to the space) and breaks into three. This shape does occur at the Sinai Peninsula and again at Djibouti (African Rift Valley meets the Arabian plate). Sagittarian Milky Way (talk) 17:09, 4 December 2014 (UTC)

SemanticMantis made a really interesting response on the mud cracks, but... I'm not sure that's what went on here (if anything at all special went on). The edge of Gondwanaland was more or less a straight line, and our map in the article has it marked as a major fault line, and things broke apart three ways from a point on the edge. For all I know (i.e. nothing) the continent might have hit something that "pushed into it" and broke it apart (maybe that hotspot?) but alas, I don't know this at all; hell, I don't even know which way it was moving at the time. I can only say that so far from what's said here I don't have any more reason to think it is like mud cracks than that. :) Hmmmm... actually I found something like this suggestion just now in Great Escarpment, Southern Africa; alas it cites an offline source that sounds a little pop science, but hopefully there's some fire to go with that smoke... Wnt (talk) 18:06, 4 December 2014 (UTC)

Yes I just like mud cracks and wanted to share some info but I'm not convinced the processes behind their patterns will tell us much about continental break up. Does anyone remember the name of our contributor that is a real geologist? Mark or Mike something maybe? Ah it's @Mikenorton: - I for one would like to hear his thoughts on this topic. SemanticMantis (talk) 19:06, 4 December 2014 (UTC)

Ah, here it is, triple junction. Note that there is no link in that article to quadruple junction. Sagittarian Milky Way (talk) 20:00, 4 December 2014 (UTC);

Also, Medeis said that any dripping continents are likely to point towards the Sun from most of the civilizations. Neil Diamond would probably say that low temperate acreage continents (therefore narrow and N-S oriented and/or pointy and/or not extending into much of the temperature zone at all), and disease-ridden low latitude areas are not conducive to civilizations, making the further pole likely "up" on maps, thus increasing the chance that sentient globalized civilizations have continental drip. Sagittarian Milky Way (talk) 20:28, 4 December 2014 (UTC)

Did you perhaps mean Jared Diamond there? Though admittedly, how awesome would it be if it turned out Neil Diamond actually had an amateur interest in historical ecology? "EVERYWHERE, AROUND THE WORLD, THEY'RE COMING TO AMERICA -- because-they-failed-to-appropriately-manage-population-growth-and-were-forced-to-rely-on-one-staple-foodcrop-for-sociopolitical-reasons-thus-leaving-them-vulerable-to-a-single-form-of-blight-which-devistated-said-crop-leading-to-mass-famine-and-now-they're-in -- THE EYE OF THE STORM!" Snow talk 06:11, 5 December 2014 (UTC)

Probably. It's been 7 years since I read that book, and Neil Diamond might be a much less obscure name to older persons. I never even heard the name Billy Ocean till I saw a modern sitcom. Now that's an obscure singer. Thin, tapering pole-pointing continents likely lose a lot of their limited mid-latitude real estate to N-S mountains and the resulting rain shadow deserts. Therefore drip is more likely than "continents point up like arrows" in planets with sentients globalised enough to have agreed which compass direction is up. Sagittarian Milky Way (talk) 21:32, 5 December 2014 (UTC)

The assumption does not apply to Australia, Eurasia (or Europe and Asia) or Antarctica. Beyond that it's what called historical accident. (For example, if you flip seven coins, a majority of them will point in some direction or other, regardless of whether they are quarters or dimes.) There's nothing about continents essentially that makes them have to have their pointy bits face one way or the other. One might also adduce the fact that most of the worlds major civilizations originated in the half of the globe that has the most land, and that the smaller parts lie on the other side of the equator, and therefore in the direction of the sun so far as the Northerners are concerned. μηδείς (talk) 21:15, 3 December 2014 (UTC)

To be fair, I don't think we can say with any certainty at this point whether it is a historical accident -- that is, just one of any number of possible combinations the landmasses might have taken on a planet with similar conditions, each of which was more or less equally likely -- or not. At present the answer "this is just the manner in which tectonic and other geological pressures happened to drive continental drift and the overall morphology of the continents" might have to suffice, but further study might reveal that principles of entropy and/or other physical constraints tend to result in landmasses with a tapered shape. We are extremely limited in the assumptions we can make here, owing to the facts that A) we've really only studied these phenomena in significant detail on one planet, B) many of the forces at work are of an extremely complex nature and difficult to directly examine, and C) the scale of geological time is such that we've only been making direct, contemporaneous observations of the relevant phenomena during an exceedingly tiny portion of the time over which they have developed. All of which is not to say that the models upon which modern geology is based don't seem to be quite stable and reliable, but rather that it will be a long time, I think, before researchers can fully appreciate just how much we don't know at this point. Snow talk 01:48, 4 December 2014 (UTC)

That's fine, I am sure you simply don't understand what is meant by accident in the linked article, so worry not. μηδείς (talk) 03:00, 4 December 2014 (UTC)

I'm quite familiar with the use of the term in that context, thank you very much, Medeis. If you would care to be more specific in where you find my reasoning and representation of the facts as regard the relevant areas of science to be flawed -- as opposed to lobbing pointed, frankly passive-aggressive comments that serve no purpose other than to a personalize a discussion that is not well served by a such a change in tone, when no personal insult or judgement was implied on my part -- well then, I'll be all ears. As I see it, you were suggesting that the morphology of terrestrial continents, or at least their orientation with regard to the poles when they are tapered, is largely, or purely, the result of random chance, with little or nothing in terms of physical forces which would predispose them to particular shapes or orientations -- your coin analogy in particular leaves very little doubt in my mind, at least, that this was your position. I was simply pointing out that nothing in our current understanding of geophysics proves this position to be true or even likely. If you have a source which demonstrates otherwise, I'd be happy to eat some crow in exchange for seeing it, but failing that, your response was clearly speculative, and I was simply trying to clarify the matter some for the OP. Personally, I don't feel the Ref Desks are the appropriate place for a contributor who can't have their assumptions questioned without responding with irritable, acerbic comments of the "Well, I'm sure you're just ignorant -- that's alright, don't worry about it." variety. For that matter, I'm fairly certain we have a policy suggesting it's not appropriate to Wikipedia in general.... Snow talk 05:16, 4 December 2014 (UTC)

I'm actually tempted to agree with Medeis that this is an accident of history, and that it could have come out quite differently -- but I agree with you that we surely can't assert that with any certainty. Also ol' Medsy is known to be sporadically rude and irritable here so I suggest you ignore that like many of us have learned to do :) SemanticMantis (talk) 19:06, 4 December 2014 (UTC)

Well, quite honestly SemantoManto, I've observed in the past that we tend to be very much on the same page for most issues that we both comment on, but it seems our opinions may diverge here a little here as regards which possibility feels more intuitively likely -- though clearly we agree on the broader point that we don't have nearly the information necessary to make a strong claim one way or the other. But let's start with a statement of fact that the direction of the conversation thus far has caused us to neglect -- the truth is almost certainly somewhere in the middle. That is to say, there are almost certainly some constraints on the overall probabilities of possible morphologies. Afterall, we're not talking about a situation like a simple suspension here with a straightforward probabilistic outcome defined primarily by a single force, like diffusion, that can be expected to largely overwhelm all other relevant forces. In this case we are starting with a number of different elements and forces, bound into structures and processes that will necessarily put limits on the variety of outcomes that can result from their interactions. So this is not a black and white question -- that is, that continents on earth-like planets can either be any possible shape or destined to take highly specific shapes; rather it's a question of the degree of variability in the results that these systems produce, and indeed the very reason I responded in this thread to begin with was to point out that, from the information and understanding we currently possess, there's really virtually no evidence to suggest where the reality lays in that huge spectrum of possibility. As we explore continental formation on other, similar planets, and gain more insight into the geological history of Earth itself, we made find the processes that determine continental shape to be highly regular or highly irregular, but evidence for one likelihood over the other is virtually nonexistent at present. I'm certainly not arguing that entropic principles are not at work here; point in fact, they are essential to my assumption that certain morphologies are going to be more likely than others. I think we can both agree, for example, that a continent in the shape of a perfect square or octagon seems highly unlikely -- though if in fact the continents did take on such geometrically regular and symmetrical forms, we'd probably be even more inclined to assume more regular principles in their formation. But that doesn't mean every shape and orientation under the sun is equally likely, and combining what we do know with my general understanding of how shape tends to form inside natural systems in accordance with deterministic principles and within certain constraints, I'm inclined towards a somewhat different intuitive assumption as to where in the spectrum between regularity and irregularity these phenomena exist. But of course the key element that separates that perspective (and yours) from that of Medeis is that I recognize this intuition is, at most, a best guess and not supported or discounted by any refined models or any substantial amount of direct evidence.

And yes, I am aware that Medeis has been noted for such comments from time to time, but, for my own part, the fact that it is a recurrent behaviour doesn't make me prone to dismiss it as a simple idiosyncrasy, but rather makes me more inclined to point out that it's not appropriate. Actually, it was the fact that I had noted another waspish response to another contributor immediately before I read the comment directed towards here me that drove me to underscore the point in this thread. Most here manage to respond to criticism of the information and positions they forward like the adults and experienced contributors that they are and so can Medeis. Snow talk 00:27, 5 December 2014 (UTC)

Again, there's no essential connection between the forces that form continents in general, and the historical accident that South Africa, the cono del sur, and Central America all narrow more or less acutely in a direction we call towards the south. No doubt if Alaska pointed south we'd also say the Aleutian peninsula showed NA narrowed to the south. This is exactly like flipping coins; of course there are preceding forces that determine their fall, but there's no essential connection between the nature of a (fair) coin and which way it happens to land in any single toss. That's the whole idea of tossing coins. Likewise some clouds look like weasels. But there's nothing inherent to the nature of clouds as a such, no natural selection of clouds, no divine preference for weasel shaped clouds, that will explain in a lawlike fashion, why this particular cloud happened to look like a weasel. If you disagree, and think there is some principle other than random initial conditions that cause continents to become pointy to the south, such that a survey of Earth-like planets will show there's some cause for south pointy continents, you can provide it. μηδείς (talk) 16:54, 4 December 2014 (UTC)

You can assert that the phenomenon is purely random chance all you like but you certainly can't prove it. Some people might have though mud cracks were purely random but if you look into my links above you'll see that is not the case. Same for snow flakes - it's reasonable to think that their shapes are just random but we know now where they symmetry comes from. There are wide classes of patterns in emergent phenomena that have recently been described in terms of first principles. Patterns can have aspects of chance as well as regularity imparted by interactions in the underlying physical processes. In many situations, our understanding of the pattern formation process is refined enough that we can predict qualities of the resulting pattern ahead of time. Again, you can believe what you like, and I actually agree with your intuition in this case -- but let's not dress up guesses as scientific fact. SemanticMantis (talk) 19:06, 4 December 2014 (UTC)

Sorry, but that's just not remotely how the empirical process works. I'm not the one who made the positive assertion -- I was simply underscoring the fact that nothing, in terms of known principles has every been forwarded in serious scientific literature for the geosciences which supports your massively broad assumption. I was stating that we just don't have the data or understanding to even begin to make a meaningful determination of how random these forces are and how much they precede from regularizing principles. You're the one who staked out a position at one of the extreme ends of that spectrum. You can't just shift the burden of proof to another party to disprove your massively assumptive assertion. I don't need proof, because I didn't make an absolutist statement for one possibility or the other, only pointed out that our understanding of the physical principles involved is still quite limited and that any assertions either way are not supported by current scientific understanding of the relevant phenomena. You, on the other hand, did make a positivist claim that there are no significant regular forces acting on the continents that would dispose them to particular morphologies or orientation of those resulting morphologies, so you do have the burden of proof secure that assertion with a detailed description of the mechanics at work -- though of course you can't in this case, which was the very point of my comments. See how that works? Or nevermind, I guess you just don't know how the scientific process operates -- don't worry yourself about it....

Look, no branch of physics, nor science generally, proceeds from the assumption that every phenomena is the result of random chance until proven otherwise; indeed, this is rarely the ultimate finding in the exploration of any natural process. So much so, in fact, that it may be that randomness doesn't exist at all, except as a cognitive phenomena, a convenient placeholder for when we observe a level of complexity we are not yet able to parse. Your weasel cloud analogy seems to suggest that you don't fully appreciate the implications of this very real (some would say all but certain) possibility; no one here suggested divine providence or natural selection as guiding forces for either geological or meteorological phenomena, but that doesn't mean they don't proceed from "lawlike" principles; relatively few clouds look like weasels but that doesn't mean that this particular morphology is not the result of deterministic forces -- our inability to predict exactly when and where it will arise does not in any way suggest that it possesses unpredictability as a natural property. Point in fact, it proceeds absolutely from our current understanding of physics that if you had an astronomical capacity for calculation, you could predict where the weasel cloud, or any other, would arise and demonstrate why. Our inability to do so is a limitation imposed by the scale and complexity of the circumstances, not any ephemeral qualities of clouds or continents which allow them to defy the mechanistic nature of the relevant areas of physics. Regardless, in this particular case you are clearly up speculation creek without a source when you state as definitive finding that the shape of the continents is nothing but a historical accident. Nothing in our current understanding of the relevant geophysics supports that assumption, and frankly I'd be surprised if our future understanding of these structures ends up demonstrating that they are not constrained to some significant degree towards at least some relatively small subset of all possible morphologies. Snow talk 00:27, 5 December 2014 (UTC)

• Rude? I have started a talk page thread on that blatant accusation. More like TLDR, and obviously not understanding that historical accident means there's no connection between the essence of what it is to be a continent and whether it is a fact that humans live on a planet where three out of seven of them point south. The premise itself is false, regardless of its silliness, and its inability to be explained with regards to any law of nature. μηδείς (talk) 01:25, 5 December 2014 (UTC)

Medeis, if you think that Antarctica doesn't narrow rapidly to a point in the south, you've not been looking at the right projections. -- ToE 04:06, 4 December 2014 (UTC)

Thanks, I'd never seen those particular projections before. μηδείς (talk) 16:57, 4 December 2014 (UTC)

PLL vs band-pass

what does this chip do? it says in the datasheet, inter alia: "The KA567 is [a] monolithic phase locked loop system designed to provide a saturated transistor switch to GND, when an input signal is present within the passband. External components are used to independently set [the] center frequency bandwidth and output delay." as far as I understand the the chip doesn't decode FM (ie smooth frequency->voltage conversion) or anything. Under the given application scenarios ("Touch Tone decoder, Wireless intercom," etc), what is the advantage of using PLL, i.e. why wouldn't a simple band-pass filter (active if needs be) plus comparator do? Asmrulz (talk) 20:57, 3 December 2014 (UTC)

This circuit is a signal-detector. You could call it a frequency discriminator, but the application data-sheet calls it a "frequency-selective tone decoder system." Its purpose was very probably for use in a touch-tone telephone, as part of a larger digital system (very probably implementing dual-tone multi-frequency signaling or a similar protocol). By itself, this ASIC does not do very much: it sets a binary output to "high" or "low" when the input sees a signal with certain specific properties.

One of the things to know about ASICs is that they are application-specific. They were designed by an engineering team for one specific application. They might sometimes be useful for other purposes, but they are tuned to meet the needs and requirements of (usually) one product or one customer. This chip, in particular, is almost twenty years old; it's almost certainly been superseded by more elaborate, more tightly-integrated circuits that implement the entirety of a touch-tone telephone's logic on a single chip, almost certainly using a microcontroller or software-programmable device. One does not commonly find new touch-tone telephones, let alone new circuit-designs for such devices; so it will be difficult to find up-to-date documentation or application notes for these types of circuit hardware.

The advantage of using a PLL, in this case, is that one single ASIC can be used to detect many different types of signals, i.e. to configure this chip to detect one of many different, selectable frequencies. It is easier to change the input configuration using a PLL than by using an analog, discrete-component bandpass filter. (Why is this easier? Well, ... try to build yourself a tuning circuit using any of your favorite methods. If you want to change the values of an RLC filter, you either need to use a varactor, or a potentiometer, or tunable capacitor. All of these choices are physically bulky, hard to build to precise tolerance; hard to control electrically; full of terrible parasitics! If you replace any of those components with an electronically-controlled solid-state version, you have effectively built a phase-locked loop; so you might as well use a proper circuit designed for use as a PLL).

Nimur (talk) 21:29, 3 December 2014 (UTC)

but the chip needs extrenal components, too... "f₀ is the free-running frequency of the C_L controlled oscillator with no input signal. [It] is determined by resistor R₁ between pins 5 and 6 and capacitor C₁ from pin 6 to ground"...

I just noticed it also says there, under 2) : "The voltage at pin 2, the phase detector output, is a linear function of frequency over the range 0.95 to 1.05 f₀, with a slope of approximately 20mV/% frequency deviation." Does this mean the chip can decode FM after all? (sorry for the "disinformation" in my initial post) Asmrulz (talk) 22:35, 3 December 2014 (UTC)

can a low- or a high-pass actually decode FM? if it's not too steep and the carrier frequency is somewhere halfway between the upper and lower end of either edge on the curve? Asmrulz (talk) 22:46, 3 December 2014 (UTC)

found the answer here. it can and it's called "slope detection" Asmrulz (talk) 09:17, 4 December 2014 (UTC)

Yes, google for "567 intercom", there are reference circuits also for intercoms in some manufacturers data sheets. The device is produced by several semiconductor vendors, see NE567, LM567. Before using this, ensure your circuit is compliant to the EMI emission regulations. Check the maximum operation frequency of your sample's datasheet.--Hans Haase (talk) 09:51, 4 December 2014 (UTC)

er... I'm not making a wireless intercom... or anything that radiates away radio frequency (at least, intentionally:) ). But thank you all the same, I've bingoogled up the datasheet Asmrulz (talk) 16:41, 4 December 2014 (UTC)

This application shows how FM is beeing decoded. It is the same to control the AFC or tuning meter. --Hans Haase (talk) 14:33, 6 December 2014 (UTC)

Conversion

I'm trying to convert how much thiamethoxam (in ppm) is applied to one kernel of corn, but my estimates vary largely and I'm not sure which is correct, if any. [5] (p. 11 and 12) states not to allow more than "0.21 lb thiamethoxam per acre", with 75,000 kernels per acre assumed. 0.21 ÷ 75,000 = 0.0000028 lbs per kernel, 0.0000028 lbs to ounces equals 0.0000448. A corn kernel weighs 0.000697983522 lbs. Thus 0.0000448 ounces thiamethoxam to 0.000697983522 lbs corn, which equals 0.0641848963 ounces/pound. Using [6], 0.0641848963 ounces/pound equals 4011.556019 ppm (which seems really very high, especially when an experiment found mortality rates to be high for certain species at 4 ppm / kernel). Is this correct? How would I calculate Syngenta's recommended ppm / kernel? Seattle (talk) 21:47, 3 December 2014 (UTC)

You are assuming a cropping yield of 52 lb per acre. that is 0.000697983522*75000. I don't believe it.Greglocock (talk) 23:53, 3 December 2014 (UTC)

75,000 would be the number of seed kernels planted per acre, not the number harvested at the end. Thiamethoxam is generally used to protect seeds / seedlings at planting. Dragons flight (talk) 00:33, 4 December 2014 (UTC)

Is ascorbic acid strong enough to dissolve skin?

Is it? 140.254.136.160 (talk) 22:00, 3 December 2014 (UTC)

The most straightforward way to evaluate risks like this in a hurry is to look at the NFPA code in the article infobox and hopefully on the chemical bottle. There is much to be said for practical and empirical experience versus chemical theory where your skin is concerned! If you mouseover the blue "1" it says it can be irritating but not exceptionally damaging. It's interesting to compare this with acetic acid, found in vinegar, which has a rating of 3, even though acetic acid has a pKa of 4.7 whereas ascorbic acid has a lower pKa of 4.1. My assumption ...... might be wrong ..... is that this has to do mainly with the fact that acetic acid is a very small molecule so you can get it very concentrated, since it's only the concentrated solution that gets the "3", not vinegar. Ascorbic acid, being bigger (176 vs 60) and also less soluble in water (330 vs essentially 1049 g/l), can't really reach the same concentration at your skin. Wnt (talk) 22:35, 3 December 2014 (UTC)

How does a multicellular, eukaryotic body treat heat-resistant pathogenic bacteria?

How does the said body treat heat-resistant pathogenic bacteria? If fever is the body's response to foreign microbial invasion, then what happens if the bacteria is heat-resistant but the body's own cells and enzymes start to denature due to the excess heat? Are there other mechanisms that the multicellular, eukaryotic body can use to defeat foreigners? 140.254.136.160 (talk) 22:09, 3 December 2014 (UTC)

Fever has a wide range of effects, such as on the body's own immune cells, and isn't simply an attempt to cook the invading organism. Look over the article and ask again if you have more specific questions. Wnt (talk) 22:38, 3 December 2014 (UTC)

Absolutely -- immune response is a fabulously complex process and most every eukaryote has a wide arsenal of mechanisms which can be utilized in response to pathogens; pyrexia is not even really the first or most significant line of defense and, as Wnt has already noted, its utility is believed to be more about augmenting other aspects of the immune response than directly damaging or inhibiting the pathogen in question -- generally speaking anyway. A good first stop for the info you seek is Immune system (peculiarly, we don't have an entry specifically on the human immune system as we do for a lot of other physiological systems, but you're request seemed more broad in any event). I'm happy to say we have a pretty decent selection of fairly robust articles on immunology at present, but given the focus of your question, I would start with Leukocyte, Lymphocyte, T cell, B cell, NK cell, Macrophage, Antigen, and complement system. Snow talk 22:50, 3 December 2014 (UTC)

Correcting a user's name in sandbox

we don't correct other people's user pages, see help or teahouse
The following discussion has been closed. Please do not modify it.
Hi there, I need to correct a user's name in Sandbox, I have managed to edit the article but it will not allow me to change the user. I need to change Phillip Norrie to Philip Norrie (only one "l" not two) please. I am editing on his behalf. My thanks in advance. First, I would suggest you read about COI and Wikipedia:Single-purpose accounts. This will save me from adding this template: {{Autobiography|{{subst:DATE}}}}, should this article go live.-- Aspro (talk) 23:51, 3 December 2014 (UTC) The appropriate place for this particular request is actually the the Help Desk, but I'll go ahead and answer it anyway, since I want to take the opportunity to expand upon Aspro's comments. Changing a username after the creation of an account is actually rather a little bit of a complicated process, especially for a new editor unfamiliar with the means by which contributors communicate with the bureaucrats who have to handle the change. A guide to the whole process can be found here, but it's worth mentioning that it is probably only worthwhile for you to change the name if Mr. Norrie wants it consistent for correspondence on Wikipedia; as regards the article on Mr. Norrie, which will go into what we call article space, you can always change the article title itself at any time. That is, any article, regardless of who it is about, is an independent entity on Wikipedia and not tied to any one person's user account and the space (including sandbox) reserved for it, even if the article is about the same person to whom that account and space belongs. Once an article goes into article space, its name can always be changed through the standard move process. However, as Aspro hints at, you may be farther away from an acceptable Wikipedia article than you think. I'm presuming that the article you are sandboxing and wish to add to Wikipedia is this one and, having reviewed it, I have to inform you that it does not yet meet our standards for inclusion on Wikipedia, most specifically as regards the crucial requirements found at WP:Notability; at present your article doesn't have any reliable, third-party sources, not any secondary sources whatsoever, which are absolute requirements for adding this manner of content to the project. Further, my overall impression of the content is that is very promotional in tone, which is not really acceptable to our purposes here either. In truth, you might want to reconsider whether this article is really appropriate to Wikipedia as a general-purpose encyclopedia; certainly you will need better third-party sourcing that establishes notability before you proceed. If I may suggest, if you want to proceed, you might consider seeking mentoring via The Teahouse, an in-wiki forum that is meant to assist new users in acclimating themselves to Wikipedia policy and procedures. Snow talk 02:25, 4 December 2014 (UTC)