Hi. How would I go about finding the required speed of collision in terms of c (light speed) for a deuterium - tritium fusion? Thanks--InverseSubstance (talk) 02:40, 29 May 2011 (UTC)[reply]

If you assume that the hydrogen atoms are free (unbound), then mean kinetic energy is (1/2)kT or ${\displaystyle (1/2)mv^{2}=(1/2)kT}$. Use whatever units for velocity you want -- fraction of c. 70.116.11.171 (talk) 04:06, 29 May 2011 (UTC)[reply]

So that means v = √ kT / m ? Where k = Boltzmann's constant, T = 1 billion kelvin (say), and m = mass of proton ? --InverseSubstance (talk) 05:54, 29 May 2011 (UTC)[reply]

You can solve the abstract problem of the minimum relative velocity at which two objects with rest masses ${\displaystyle m_{1}}$ and ${\displaystyle m_{2}}$ can collide and produce products with total rest mass ${\displaystyle m_{f}}$ like this: choose to work in the rest frame of the object of mass ${\displaystyle m_{1}}$. Then its four-momentum is ${\displaystyle (m_{1},0)}$ and the four-momentum of the other object is ${\displaystyle (\gamma m_{2},\beta \gamma m_{2})}$, where β is the relative speed as a fraction of c, and γ is the corresponding gamma factor. The total momentum (before and after) is ${\displaystyle (m_{1}+\gamma m_{2},\beta \gamma m_{2})}$. The length of this momentum vector must be larger than ${\displaystyle m_{f}}$. This gives ${\displaystyle (m_{1}+\gamma m_{2})^{2}-(\beta \gamma m_{2})^{2}>m_{f}}$, or ${\displaystyle \gamma >{\frac {m_{f}^{2}-m_{1}^{2}-m_{2}^{2}}{2m_{1}m_{2}}}}$. The equality can also be written ${\displaystyle m_{f}^{2}=m_{1}^{2}+m_{2}^{2}+2m_{1}m_{2}\cosh \alpha }$, where α is the rapidity. It's the Lorentzian version of the law of cosines. -- BenRG (talk) 06:11, 29 May 2011 (UTC)[reply]

Ok, so ${\displaystyle m_{f}}$ = rest mass of a deuterium atom (say), ${\displaystyle m_{1}}$ & ${\displaystyle m_{2}}$ = mass of a proton. I just realized now its a proton proton fusion. Is that all right? --InverseSubstance (talk) 06:35, 29 May 2011 (UTC)[reply]

I just noticed that my answer is irrelevant because proton-proton fusion is exothermic. Sorry. There is technically no minimum relative speed for reactions that release energy. They will happen (slowly) by tunneling at arbitrarily low relative speeds. The classical threshold energy (without tunneling) is given by the height of the Coulomb barrier. Even classically, the reaction will happen in a gas of arbitrarily low temperature because some particles will have larger-than-average speeds. I don't know the height of the Coulomb barrier for proton-proton fusion. -- BenRG (talk) 18:34, 29 May 2011 (UTC)[reply]

That's interesting because I was thinking the answer would be something like 'it takes 3.5Mev (say) to over come the Coulomb barrier, and 3.5Mev is enough energy to accelerate a proton of mass p to a velocity of v km/sec. This v is then a fraction of the speed of light. So this approach isn't helpful? — Preceding unsigned comment added by InverseSubstance (talk • contribs) 22:19, 29 May 2011 (UTC)[reply]

That's the approach ignoring quantum mechanics. Quantum tunnelling allows fusion to occur even when the energy isn't enough to overcome the Coulomb barrier - the nuclei can "tunnel" through the barrier. The closer they are to getting over the barrier anyway, the more likely they are the tunnel, but they can do it at any energy level. Converting the energy into a speed is also not particularly useful. It is correct, but usually we don't have two nuclei that we want to fuse, we have a whole cloud of nuclei. In that case, it's better to talk in terms of the temperature of the cloud (which is essentially the average speed of the nuclei) rather than the speed of individual nuclei. --Tango (talk) 23:00, 29 May 2011 (UTC)[reply]

I've tried the Google, and failed.

I remember a photograph of Abraham Lincoln at the Boston Museum of Science. It was a low-resolution image -- 16 x 16 maybe -- that demonstrated that faces are recognizable with a minimum of detail or information. I'm fairly certain the image is just of his face, and he's wearing a top hat; the image shows the hat, his face, and his goatee.

Anyone know where I can find a copy of this image (short of going to the MOS and snapping a picture)?

Thanks in advance, 70.116.11.171 (talk) 03:55, 29 May 2011 (UTC)[reply]

PS. I first posted in "Computing", but after looking through the mostly technology-related questions there, thought I'd try here too. Sorry for any duplication.

If you Google for "Julesz Lincoln picture", you will get a bunch of relevant hits, including versions of the image. Looie496 (talk) 04:04, 29 May 2011 (UTC)[reply]

Thanks for the tip. I saw that one in my search, but I'm almost 100 percent sure that's not the one in the MOS. The one I remember has his signature top hat. It's also straight on to his face, not from the side. Any others? TIA, 70.116.11.171 (talk) 04:09, 29 May 2011 (UTC)[reply]

The museum may have created a new example from a public-domain Lincoln image just to avoid Harmon and Julesz's copyright. The alternative, that there's a second pixelated Lincoln image in wide distribution, seems unlikely since Julesz's is so famous (and I can't remember ever seeing another). This page says that Harmon and Julesz published "block portraits of Abraham Lincoln", plural. I don't have online access to the original article. -- BenRG (talk) 17:17, 29 May 2011 (UTC)[reply]

I don't think it's recognizable by face, but only because there are few well known examples of people with both beards and top hats. Wnt (talk) 18:43, 30 May 2011 (UTC)[reply]

Can any one suggest me circuit diagram for the mp3 player with memory card i want it and also audio or mp3 comparator (Ic 741 can used ah?) and how to connect a circuit to computer (output of the circuit is txt files and computer will generate mp3 files as output)? — Preceding unsigned comment added by Kanniyappan (talk • contribs) 06:21, 29 May 2011 (UTC)[reply]

You mention the 741 which is an Operational amplifier and here is its circuit. However it is no use in building an MP3 CD player which is a complex digital device.. TXT files are for text, not audio. Cuddlyable3 (talk) 15:03, 29 May 2011 (UTC)[reply]

If you do a Google search on "mp3 player project", there are several kits you can buy and circuit diagrams you can download. However, this would be a fairly complex electronics project, and I wouldn't recommend it if you don't have much experience in the area. Tevildo (talk) 21:04, 29 May 2011 (UTC)[reply]

Kissing tonsils is a familiar term. But is there something which is identified as non-kissing bilateral tonsillar edema, the term "non-kissing" is used and is related to tonsils. Is there something like "non-kissing tonsils"? aniketnik 08:21, 29 May 2011 (UTC) — Preceding unsigned comment added by Aniketnik (talk • contribs)

I thought this was a question about tonsil hockey, a game which I have played many times in the past. But alas no! --TammyMoet (talk) 10:32, 29 May 2011 (UTC)[reply]

"Non-kissing bilateral tonsillar edema", taken as a whole, is not a formally recognized entity. It can be translated into ordinary English, though: it means tonsils that are swollen on both sides due to fluid accumulation, but not so swollen that the tonsils on opposite sides come into contact with each other. Looie496 (talk) 17:06, 29 May 2011 (UTC)[reply]

How is the figure of 3.5 meter under keel clearance arrived at ? — Preceding unsigned comment added by 202.63.224.53 (talk) 17:03, 29 May 2011 (UTC)[reply]

By a lengthy process of negotiation. The higher the clearance, the less chance of ships running aground but the fewer ships are able to pass. According to this book, the Indonesians wanted 4.6 meters (to maximize safety) but Singapore wanted 2.6 meters (to maximize traffic); they settled about halfway between. Unfortunately it took a disastrous accident to get them to come to any agreement at all. Looie496 (talk) 17:22, 29 May 2011 (UTC)[reply]

1. How far do Humpback_whale travel? 2. Are there any sharks in Colorado or Alaska? Thanks! Neptunekh2 (talk) 21:24, 29 May 2011 (UTC)[reply]

In Colorado...? --Elen of the Roads (talk) 21:57, 29 May 2011 (UTC)[reply]

Try Downtown Aquarium, Denver --Digrpat (talk) 22:09, 29 May 2011 (UTC)[reply]

On your first question, see the first sentence of the second paragraph in Humpback whale. Deor (talk) 00:12, 30 May 2011 (UTC)[reply]

There are sharks in Alaskan waters, mainly salmon shark (see that article), though other species have been reported.[1] --Colapeninsula (talk) 09:21, 30 May 2011 (UTC)[reply]

Hello all. I was pondering liquids the other day, and before I had confused myself too much, I posed a question. The molecules of liquids have very little friction and they slip and slide off of each other, which makes the substance act like a liquid, right? But what if the molecules were to increase their friction? Would this make the fluid more viscous? Or would this change some other property of the fluid? And is such a feat possible? Is there some way to increase a fluid's molecules' friction? Thanks! Stripey the crab (talk) 23:29, 29 May 2011 (UTC)[reply]

See Temperature dependence of liquid viscosity. Very technical article but it indicates you could change viscosity by changing temperature. You might also try the article Viscosity.

Wanderer57 (talk) 23:51, 29 May 2011 (UTC)[reply]

If you have ever heated corn syrup, you'll know that it becomes quite thin like water. Alternatively, if you put it in a refrigerator, it will become as thick as some trees' gum. Plasmic Physics (talk) 00:56, 30 May 2011 (UTC)[reply]

Regarding your statement that liquids (and I will extend that to all fluids) have very little friction, I'm not sure that's quite right. While solids have a very concentrated site of friction (the boundary between them), where it's easy to observe the effects of friction, like heat and wear, fluids can have friction throughout their entirety. So, the total friction might well be more with fluids, and especially so with thicker fluids. StuRat (talk) 06:22, 30 May 2011 (UTC)[reply]

The OP's statement is about friction between molecules, not surfaces. The relatively high friction between molecules of solids is the reason that continuous movement occurs only at their boundaries. Cuddlyable3 (talk) 11:17, 30 May 2011 (UTC)[reply]

Concepts such as friction, slipping, and sliding are not meaningful at the level of molecules: all molecules can do is attract or repel each other. Concepts such as friction only come into existence when you have unimaginably large numbers of molecules interacting with each other within a region -- literally unimaginable, quintillions or sextillions. Looie496 (talk) 22:48, 30 May 2011 (UTC)[reply]

No. Friction is meaningful at the atomic level. Determining the forces required to move atoms past each other is a challenge in designing nanomachines. In 2008 scientists for the first time were able to move a single atom across a surface, and measure the forces required (see above link). Cuddlyable3 (talk) 10:34, 31 May 2011 (UTC)[reply]

The question has already been answered - temperature, and pressure affects the internal friction of a fluid. Plasmic Physics (talk) 23:13, 30 May 2011 (UTC)[reply]

I know the question has already been answered however I would like to point out a practical everyday example of this. The designation of motor oil indicates how the viscosity changes. 10W30 for instance the 10 and 30 refer to the hot and cold viscosity as I understand. HominidMachinae (talk) 22:46, 2 June 2011 (UTC)[reply]

If I have sapients who live underwater, would a water-powered vehicle with a driver, looking sort of like a submarine but filled with water, be of any use in getting the passengers places without requiring them to move about consciously? Would they be able to swim just by sitting pasively in the water, or does an underwater creature have to use energy to swim? I want to know if my underwater people could have any use for a plastic vehicle. Subliminable (talk) 00:17, 30 May 2011 (UTC)[reply]

Yes, an underwater creature does have to use energy to swim - the alternative is to fasten yourself to a rock and wait for your food to float towards you (sessile is the technical term), or float where the currents or tides take you, neither of which is a good start for developing intelligence. _Powering_ the underwater car might be a bit tricky - it can't be water-powered, it'll need some other energy source, and your people won't have fire. Clockwork, perhaps? Tevildo (talk) 00:40, 30 May 2011 (UTC)[reply]

I'm not sure that the idea of an enclosed car is all that useful underwater, given the amount of added resistance from any large vehicle. On the other hand, I'd think that for underwater dwellers, any method of creating a smooth, slippery tube should be quite useful - a simple device to raise water level higher at one end and release it abruptly should produce a means of propulsion at speeds unattainable in the ocean proper. Or a cable set in an area crossing a strong current might allow people to quickly cross at an angle to it by holding onto something akin to a zipline. I'd think that a civilization armed with a method to create plastic-like biopolymers, a good set of tidal power technologies, and a good map of the ocean currents should be able to come up with very useful transportation technologies even in the absence of fire and metal. Supplementing plastic scaffolds with robust constructions from stone, clay, or other minerals, geothermal power from mid-ocean ridges and black smokers (perhaps, in time, even some low temperature metal smelting) might add useful tools to this. Wnt (talk) 03:56, 30 May 2011 (UTC)[reply]

I'm not sure what "Water powered" means in this context. For a variety of reasons, no society will ever use water as fuel. "Water powered" usually refers to water-wheels on dams and stuff. I'm not sure how a vehicle could be "Water powered" unless you just mean a boat that drifts downstream.

If your merpeople have the technology to build engines, then a DPV would probably be the equivalent of a motorcycle, to them. It might even be possible to make one out of clockwork.

If you're imagining a modern sport submarine accidentally being lost to the depths and salvaged by merpeople, I'm not sure how useful they'd find it. Very few sport submarines could travel faster than one would reasonably expect a mermaid to swim, perhaps none. They're not good for long-distance either, though I suppose if you took out the air-tanks and put in larger batteries maybe they'd be useful for that.

If I were a merperson who needed to get somewhere quickly, and had access to a plastic craft. I would consider making a surface boat that could be filled with enough water for me to breath. A surface sailboat would certainly be useful for a merperson. On a windy day it would go much faster and farther anything can swim. APL (talk) 05:53, 30 May 2011 (UTC)[reply]

Where do baby merpersons come from? What's the difference between a merman and a mermaid, and why? Cuddlyable3 (talk) 11:10, 30 May 2011 (UTC)[reply]

Mermen have smaller breasts and never were bikini tops Nil Einne (talk) 13:40, 30 May 2011 (UTC)[reply]

...nor wear them. Cuddlyable3 (talk) 20:22, 30 May 2011 (UTC)[reply]

Actually your vehicle designed to deliver occupants who are themselves submerged in water already exists. A sort of open topped submarine so to speak. cf: SEAL Delivery Vehicle Hcobb (talk) 18:20, 30 May 2011 (UTC)[reply]

Human torpedoes have been in use since at least WW2. 92.24.191.98 (talk) 23:13, 30 May 2011 (UTC)[reply]

If nothing else, a vehicle would be useful to merpeople as a way of hauling cargo. Even if it went slower than they could swim on their own. If you needed to haul a load of clam-shells to the bikini factory, a sub would be a heck of a lot easier than trying to drag them around in giant sacks. APL (talk) 20:45, 30 May 2011 (UTC)[reply]

You might want to read Surface Tension by James Blish Greglocock (talk) 05:03, 31 May 2011 (UTC)[reply]

Yes. That is a tremendous story. APL (talk) 06:08, 31 May 2011 (UTC)[reply]

which elements and particles are there in combination of solar wind?--78.38.28.3 (talk) 09:07, 30 May 2011 (UTC) iran may 2011[reply]

Our article Solar wind may be useful. It says mainly electrons and protons. --Colapeninsula (talk) 09:22, 30 May 2011 (UTC)[reply]

If some particles such as alpha ray and electron accelerate in solarmagnetic field that might other particles such as carbon and nitrogen and oxygen be accelerated too. my main aim of this question is this :is there any other particles observed in combination of solar wind?

a. mohammadzade--78.38.28.3 (talk) 05:25, 31 May 2011 (UTC) — Preceding unsigned comment added by 78.38.28.3 (talk) 05:22, 31 May 2011 (UTC)[reply]

Solar wind contains tiny, tiny, incredibly trace quantities of heavy elements. Stellar nucleosynthesis explains how heavy elements are created in the sun; our coronal mass ejection hints that in such eruptions (where the density and quantity of ejecta is much larger than the steady-state solar wind), scientists can see spectra from heavier elements. This paper from Solar Physics in 1993, Material Ejection, reviews several standard techniques for measuring the contents and the types of particles emitted from our Sun in various different types of ejections. Nimur (talk) 16:18, 31 May 2011 (UTC)[reply]

Does a colony of ants considered as a superorganism have a brain? Count Iblis (talk) 16:18, 30 May 2011 (UTC)[reply]

Yes, thousands of them. If you aren't satisfied with that answer, please clarify what you are trying to figure out. It seems likely that you already know all of the relevant facts. Looie496 (talk) 16:31, 30 May 2011 (UTC)[reply]

Yes; if you understand that the language of the 'superorganism' is patently metaphorical, then the 'decision-making' functions of a brain are handled via emergent behaviors of the colony, which arise from each ant's local interactions with their peers and environment. (e.g temperature and humidity regulation in a colony of leaf-cutter ants). SemanticMantis (talk) 17:55, 30 May 2011 (UTC)[reply]

The language of the superorganism is really not much more metaphorical than the language of the organism. An organism is a collection of closely cooperating cells that share a common genome; a superorganism is a collection of closely cooperating organisms that share strongly related (but usually not identical) genomes. Looie496 (talk) 18:01, 30 May 2011 (UTC)[reply]

There is a theory out there that says a superorganism has a superbrain, where each individual member acts like a pseudoneuron. Plasmic Physics (talk) 22:49, 30 May 2011 (UTC)[reply]

Yes, that is what I mean. So, how sophisticated would such a superbrain of an ant nest be? Count Iblis (talk) 01:20, 31 May 2011 (UTC)[reply]

I'm not sure that I understand this notion of a superbrain in social insects. If it is more than a metaphor, what is it in fact ? I share my living space with a mature weaver ant (Oecophylla smaragdina) colony that is probably well on its way to reaching the upper limits of colony size for this species. It certainly has several hundred thousand major and minor workers spread over hundreds of nests. Other than an apparent intent to make life quite difficult for almost everything near it, what evidence would demonstrate the existence of an actual non-metaphorical "superbrain" ? Sean.hoyland - talk 03:12, 31 May 2011 (UTC)[reply]

I think ants lack some prerequisites for such a "super-brain":

1) There needs to be a method to record individual thoughts, determine which are important to the colony, prioritize them, and then convey them only to the relevant members of the colony.

2) There needs to be a way to convey such thoughts to subsequent generations.

As far as I can tell, the only animal to achieve this is humans, due to the invention of writing and, more recently, the Internet and globalization, and thus only we have a super-brain (meaning that collectively humanity knows far more than any individual alone knows). StuRat (talk) 04:53, 31 May 2011 (UTC)[reply]

An ant mill may be of interest when considering the intelligence of ants. I think it shows that there is no great overriding intelligence, but just culture with the same propensity for self-destructive trends as human culture. But probably someone else would disagree. Historically though, the idea of ants as a "super-organism" comes from their mode of reproduction, not their mode of thinking. If the Nazis had won the war and started having designated genetically pure Mothers inseminated by a tiny number of Aryan Heroes, before long humans would be a "super-organism". Not exactly a step forward though. Wnt (talk) 19:22, 31 May 2011 (UTC)[reply]

Is there any garden flower whose leaves look like a thistle? I have a thistle-like plant two or three feet high that has appeared in an old flower bed in the UK. It has dark green leaves, and has not flowerd yet, whatever it is. It might be some flower seed that has germinated, or it may be just a large thistle. 92.24.133.185 (talk) 16:40, 30 May 2011 (UTC)[reply]

Take a look at this poppy. Argemone mexicana. I don't know what size it gets but it looks like thistle to me. Wanderer57 (talk) 17:06, 30 May 2011 (UTC)[reply]

another picture of the same species

http://www.natureproducts.net/Forest_Products/Ornamentals/Argemone%20mexicana%201.300.jpg Wanderer57 (talk) 17:08, 30 May 2011 (UTC)[reply]

There's a chance it could be an ornamental, but I think better odds are on thistle. Thistles are amazingly aggressive plants. Several European species are highly invasive in the rest of the word, such as Carduus acanthoides and Carduus nutans. Even though native to the UK, the Cursed_Thistle is listed as an "injurious weed" in the United Kingdom under the Weeds Act 1959. Many (most?) thistles could quickly swamp the entire bed and become very painful/tedious to remove. SemanticMantis (talk) 17:46, 30 May 2011 (UTC)[reply]

It might be one of the many varieties of Eryngium, for example, a fairly common garden plant that readily self-seeds. Richard Avery (talk) 07:11, 31 May 2011 (UTC)[reply]

There has been a fashion in the UK amongst garden designers to include thistles, mainly of the Cirsium variety, in their designs. I would say, unless you can upload a picture of the plant when it flowers, we're not going to be able to really help you. --TammyMoet (talk) 09:32, 31 May 2011 (UTC)[reply]

Why have things like Thomas precession glued onto the side of quantum mechanics? Why not drop string theory etc. and focus on getting a model of the atom that actually works from first principles? Do we still not have enough computing power to solve these basic problems? The nanotech payoff from understanding how atoms really interact would be huge. Hcobb (talk) 18:29, 30 May 2011 (UTC)[reply]

These aren't the kind of problems that can be solved by just throwing lots of computer power at them. String theory is an attempt at coming up with a theory that, among other things, accurately explains atoms. The problem we have at the moment is that neither quantum mechanics or general relativity correctly explain atoms. It seems we need both of them, but they are difficult to combine which is why we end up with rather unconvincing corrections instead of a single set of first principles from which the behaviour of atoms can be derived. String theory is the current favourite such set of first principles, although it's far from fully worked out. --Tango (talk) 21:00, 30 May 2011 (UTC)[reply]

I don't think that's right. A working theory of quantum gravity would be needed for dealing with extremely high energies (at the Planck scale), or for dealing with spacetime right near the Big Bang or near the singularity at the center of a black hole, and it would be good for dealing with Hawking radiation with more confidence, but it isn't needed for a normal quantum mechanical treatment of atoms. Special relativity is needed, because the inner electrons of large atoms move at relativistic speeds (as do the nucleons, if you want to include a detailed modeling of the nucleus), but general relativity isn't needed, because gravity is normally negligible compared to the other forces when dealing with atoms, i.e., in most cases of interest, atoms normally exist within a spacetime that's so close to flat that any general relativistic corrections would be negligible compared to other errors that occur in computational quantum mechanics. Red Act (talk) 22:56, 30 May 2011 (UTC)[reply]

It's not clear to me what you are complaining about. Thomas precession is a real effect and we already have a model for it that works. There are already, as we "speak", people working on developing accurate computer models that calculate energy levels of atoms including relativistic effects. It's also not clear how dropping string theory would help solve such problems. Dauto (talk) 21:14, 30 May 2011 (UTC)[reply]

Some thoughts:

• Undergraduate quantum mechanics is nonrelativistic, but quantum field theory is (special-)relativistic; Thomas precession is built into it, not added on.
• We don't have enough computing power to solve these problems, and we never will. Quantum theories as presently defined can't be solved by brute force even in principle, because they model spacetime as a continuum. Better approximation techniques are the only way forward. Even if the standard model is supplanted by a completely finite model, doing interesting exact calculations in that model would be harder than brute-forcing an AES-256 key, which is to say that it would be impossible. It's not the case that with Moore's law all things are possible.
• We don't know the real laws of physics, so it's debatable whether the "exact" theories we're approximating are any more accurate than the "approximations". In fact, the "exact" standard model has never been given a rigorous mathematical formulation and probably doesn't exist as a mathematical object. The standard model apparently resembles the correct theory inasmuch as it's a useful guide to the development of approximate calculational methods, but the calculations work because they approximate the real physics, not because they approximate the standard model, which doesn't even exist.
• String theory research has led to useful new methods of doing (approximate) calculations in quantum field theory in cases where traditional perturbation theory (Feynman diagrams) is useless.
• We would benefit from a better understanding of atomic-scale physics (we would benefit from a faster way of solving the protein folding problem, for example), but this is not at all the same as modeling the atom from first principles—just as understanding turbulent flow is not the same as deriving the Navier–Stokes equations.

-- BenRG (talk) 23:20, 30 May 2011 (UTC)[reply]

I think an underlying motivation may be the belief that the right theory may be intrinsically beautiful. This idea dates back at least to the radio term in Maxwell's equations. If relativistic quantum theory is the true theory, one may expect it to be "elegant" in form. Of course, that is not really a scientific argument - nonetheless, an interesting one. Wnt (talk) 23:07, 31 May 2011 (UTC)[reply]

cerebrum -i n. the brain; the understanding; hot temper. Cuddlyable3 (talk) 20:11, 30 May 2011 (UTC)[reply]

The study of the brain and nervous system is called neuroscience. "BRAINOLOGY" is not an English word. Cuddlyable3 (talk) 20:14, 30 May 2011 (UTC)[reply]

εγκέφαλος, μυαλό Cuddlyable3 (talk) 20:17, 30 May 2011 (UTC)[reply]

And the greek version, that Cuddlyable3 provided, would in the latin alphabet be rendered "encephalos" (alternatively "encephalon"), used in words such as encephalitis, electroencephalogram etc. The study of diseases of the brain and nervous system is called neurology. --NorwegianBlue ^talk 21:29, 30 May 2011 (UTC)[reply]

Hello, is there another literaturic word for the Brain of the skull?,

thanks. — Preceding unsigned comment added by 79.183.27.165 (talk) 08:29, 31 May 2011 (UTC)[reply]

Hi everybody

Bones covered with special tissue is called ? 184.163.238.18 (talk) 20:39, 30 May 2011 (UTC)_ __[reply]

Periosteum? What do you mean by "special"? Tevildo (talk) 20:51, 30 May 2011 (UTC)[reply]

I am in possession of an ant farm. Inside the transparent plastic box is a brown plastic "ant hill" that the ants can crawl around on, and it has sand that is at the base of the brown plastic ant hill. The brown plastic ant hill is hollow and it's full to about the 90% level with sand. Yesterday, I dropped a little piece of banana onto the brown plastic ant hill, not close to any sand. An hour later, when I looked, the banana was covered with a single layer of sand grains. Today, I dropped a little piece of about 1/4th of a blueberry next to the banana, and in an hour, when I looked, the blueberry fragment was also covered with about a single layer of sand grains. (My unnecessarily long description of my ant farm was to try to avoid responses suggesting that the ants dragged the fruit across some sand — the fruit is where I left it, and it is not near any sand.)

Why are the ants bringing sand grains to the fruit? Are they doing this intentionally or accidentally? I am wondering whether my ants are imbeciles. Comet Tuttle (talk) 05:42, 31 May 2011 (UTC)[reply]

If you are saying that the ants partially buried the fruit, I think that is quite common behavior in a number of species. Try making the pieces smaller to see if they change from burying it to transporting it. Sean.hoyland - talk 05:49, 31 May 2011 (UTC)[reply]

Agreed. They likely have an instinct to bury food too big to move, to prevent anything else from taking it. They aren't bright enough to figure out that this instinct is silly in the ant farm, since there's nothing there to steal the fruit. StuRat (talk) 08:48, 31 May 2011 (UTC)[reply]

Interesting. This makes sense; thank you. To answer Sean.hoyland's question, it would be a stretch to say the fruit pieces are "partially buried"; it's more like the fruit pieces are sitting on a piece of plastic with sand grains all over them now. I'll try tinier pieces. Thanks! Comet Tuttle (talk) 16:54, 31 May 2011 (UTC)[reply]

I am prasanth B tech graduate, I want to start carrier in software field so please guide me for best institute… — Preceding unsigned comment added by Nvprasanthmax (talk • contribs) 06:37, 31 May 2011 (UTC)[reply]

Are you prepared to travel internationally and pay plenty of money. If so MIT is famous. Graeme Bartlett (talk) 09:05, 31 May 2011 (UTC)[reply]

They did say "online", so I'm guessing they aren't willing to travel any further than their computer room. StuRat (talk) 09:24, 31 May 2011 (UTC)[reply]

Starting a technical career is often better done by trying to start a career directly than any online courses, in the US, at least. Many managers will simply disregard potential employees whose only credentials were earned online. i kan reed (talk) 21:33, 31 May 2011 (UTC)[reply]

MIT does have free online courses such as http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/. MIT was one of the first places to have this sort of thing. Graeme Bartlett (talk) 22:03, 31 May 2011 (UTC)[reply]

For online software training there are several sites. one of them are good depending on the training requirement. I found one one online software training institute: http://www.svrtechnologies.com. many other similar sites i found but go with this for less training cost. — Preceding unsigned comment added by 125.99.194.118 (talk) 10:01, 1 June 2011 (UTC)[reply]

Have any attempts been made to scientifically measure the extent of the influence of the "celibacy requirement factor" on rates of child sex abuse by members of the clergy? For example, comparing abuse rates amongst those religious denominations which demand their clergy be celibate (mostly the catholic church, but there are no doubt others) and those denominations which allow married priests? I'd prefer to find studies which attempt to adjust for other factors and isolate the "celibacy factor". (Other factors can include the pre-screening of potential clergy, responses to allegations - hiding abusers versus rigorously investigating and removing / reporting them, level of unsupervised access to potential victims, etc). IMHO, it's not that celibacy makes people into molesters, it's that the celibacy requirement means the average, mentally healthy heterosexual individual is discouraged from joining. The result being, the ranks are disproportionatly filled with "others" (such as homosexuals and pedophiles) who don't care to marry anyways (and may in some cases even prefer not having to explain a lack of interest in marrying). Ending the requirement would not eliminate abuse (nothing can - child molestation can occur in any society) but would likely reduce it. But the issue here is not my opinions - I'm looking for studies. Eliyohub (talk) 07:17, 31 May 2011 (UTC)[reply]

This is anecdotal evidence only, but a friend of mine who at the time was studying to become a catholic priest and lived in a seminary once told me about the huge poster of a naked man which one of the students in another (German) seminary had in his room. My friend was generally amused that so many want to become a priest because, according to them, being homosexual they have no problem with celibacy anyway. But even he seemed surprised that a student in that seminary was so open about it, with no apparent consequences. So I believe you are definitely up on to something. Unfortunately I am not aware of any such studies (and wouldn't expect to be). Hans Adler 08:24, 31 May 2011 (UTC)[reply]

Hans: for interest, the English idiom you were looking for is "on to something" meaning one is "on the right track", is "approaching the truth" etc. The expression "you are up to something" means "you are doing something - I'm not sure what - that is probably wrong or illegal." I'm sure you didn't mean to imply that Eliyohub is "up to no good." :-) {The poster formerly known as 87.81.230.195} 90.201.110.101 (talk) 17:56, 31 May 2011 (UTC)[reply]

Thanks, fixed. Hans Adler 21:17, 31 May 2011 (UTC)[reply]

The casual grouping together of homosexuals and pedophiles as "others" is provocative because the former are a minority that is sizeable, legal (in most countries), politically active, healthy (by our standards) and possibly inclined to marry, while pedophiles are none of those things. The OP is disingenuous about seeking confirmation of their stated hypothesis that ending the celibacy requirement "would likely reduce clergy child sex abuse". Cuddlyable3 (talk) 09:25, 31 May 2011 (UTC)[reply]

I did NOT mean to morally equate homosexuality and pedophilia - I should have made that more clear. Apologies for the misconception. However, my point was that they both aren't interested in "marriage" in the catholic sense, thus the celibacy requirement isn't necessarily a hurdle. If they wanted to be openly gay and / or marry another man, they likely wouldn't expect to remain catholic, would they? (Again, this is NOT saying the two are remotely comparable from a moral standpoint). As an brief (and probably irrelevant) aside, to answer your other points Pedophilia is not in itself illegal (you can't outlaw an inclination) it's acting on one's feelings that's usually a crime (and rightly so). Pedophiles can engage in political activism too, albeit unlikely to be very successful or popular. The only thing pedophiles and homosexuals have in common in my hypothesis is that both are less likely to be bothered by the celibacy requirement. A hypothesis is only a hypothesis - thats exactly why I'm seeking studies on the matter, to find out if it correct. (In case this needs saying: I am NOT a pedophile.) Eliyohub (talk) 11:05, 31 May 2011 (UTC)[reply]

I think pedophiles might be inclined to marry, if they could. Child brides (no article ?) are still legal in a few places, including, until recently, some US states (to which Jerry Lee Lewis can attest). StuRat (talk) 18:18, 31 May 2011 (UTC)[reply]

The article you're looking for is Child marriage (as opposed to Child Bride). Red Act (talk) 19:51, 31 May 2011 (UTC)[reply]

OK, I added a redirect (I wish Wikipedia would automatically look for a case-insensitive match if it doesn't find one with the same case). StuRat (talk) 23:37, 31 May 2011 (UTC)[reply]

It is worth noting that the distinction between homosexuality and pedophilia was, unfortunately, quite a recent development in the U.S., with the two being conflated as "pederasty" even in such liberal icons as Allen Ginsberg's poem Howl, not to mention I believe one of Eugene McCarthy's later pronouncements on the topic in the 1968 election (didn't find that one though and I might have it mixed with 1972). In Russia, which has lagged behind the U.S. in this regard, apparently the distinction is only now beginning to be drawn.^[2] This evidence would seem to indicate that it is law that determines culture, not the other way around. Wnt (talk) 19:11, 31 May 2011 (UTC)[reply]

Back to the original question? Any studies you can point me to which attempt to isolate the "celibacy factor" on rates of molestation by priests? Eliyohub (talk) 09:29, 1 June 2011 (UTC)[reply]

This link mentions that in 1990, 58% of clergy abuse reports were from Protestant ministers, most of whom I would assume are not celibate. 75.155.136.49 (talk) 20:40, 1 June 2011 (UTC)[reply]

The United States is about 25% Catholic. 66.108.223.179 (talk) 12:54, 2 June 2011 (UTC)[reply]

How should one say "baby-philia", i mean; Pedo-philia is for children let's say by the age of 3-10 and Hebe-philia is to early adults in the age of 10-14. but how should one say Baby-philia? (0-3), and, did the Psychiatric literature ever documented such behavior ? - By the way, will we call the Normal "philia" ?, the one for (generally) from age 14? thanks. 79.183.27.165 (talk) 08:27, 31 May 2011 (UTC)[reply]

A pediatrician is a physician for children and babies[3] [4] which suggests that there need be no lower age limit for the object of Pedophilia. Alternatively Infantophilia and nepiophilia have been used to refer to a sexual preference for infants and toddlers. I altered the section title for ease of reference. Cuddlyable3 (talk) 09:02, 31 May 2011 (UTC)[reply]

The suffix -philia is rooted in the Greek philos loving or dear. It can occur in harmless examples of enthusiasm such as audiophilia. Cuddlyable3 (talk) 10:42, 31 May 2011 (UTC)[reply]

I have to say, I'm surprised that there isn't some Latin-based language where people say that the local priest is a pedophile because he loves children ... in an innocent sense ... with inane consequences. But in reality there's the incident mentioned by Richard Dawkins^[5] where, it is said, vigilantes in Wales trashed a pediatrician's house...^[6] (perhaps they should have pursued separatism instead?) Wnt (talk) 18:17, 31 May 2011 (UTC) [reply]

Should mothers trust someone who says "Let the little children come to me..." ? Cuddlyable3 (talk) 19:40, 31 May 2011 (UTC)[reply]

By the way, by the age of 14 you're probably into the territory of ephebophillia, since most people are through the first stages of puberty by that point. 98.209.39.71 (talk) 20:46, 31 May 2011 (UTC)[reply]

Can one suffer from shingles (Herpes zoster) multiple times, or is it one of the once-you-have-it-you-can't-get-it-again illnesses? I've read the article, but if it says anything to answer my question, I missed it. Nyttend (talk) 12:39, 31 May 2011 (UTC)[reply]

This following is pure OR. You get shingles after having chicken pox. The virus becomes dormant in the nerves, and is awakened at some future point by a trigger. The answer to your question is, you can only get chicken pox once but once you have had it, you can get shingles many times. --TammyMoet (talk) 13:29, 31 May 2011 (UTC)[reply]

I expected there would be something in the article (which is fairly detailed) and after some searching (first tried 'multiple', then 'more t') found:

Repeated attacks of herpes zoster are rare,[10] and it is extremely rare for patients to suffer more than three recurrences.[14]

In retrospect repeated or recurrence should have been the first and second things I tried.

Nil Einne (talk) 14:32, 31 May 2011 (UTC)[reply]

Some (older) GP's think Zoster is getting more common. In times past, people that got chicken-pox developed full immunity which was repeatedly reinforced by contact with teenagers suffering the diseases. However, immunologist are now thinking that inoculation against this virus means that the immune response only produces a sort term antibody response which wears off with time. This results in an attack of very painful shingles because their other immune responses have not been primed. Of course, if everybody in the world could be given chicken-pox inoculations, then maybe it could be eradicated -but the Gates foundation is concentrating on other viruses. So to answer the OP. Yes, if an individual's congenital natural immunity does not protect it from an acute chicken-pox infection and if the same individual is denied the the primary response being reinforced by contact with other infected individuals, then there exists ample opportunity for further shingles attacks. But don't worry, this is mainly a problem for those that live in the US where chicken-pox inoculations are common. Of course, for those who's primary immunity saves them from contracting chicken -pox in the first place, then they don't have to worry about get shingles later.--Aspro (talk) 22:13, 31 May 2011 (UTC)[reply]

There is also a vaccine against shingles, though. It's one of the supermarket-type, so you don't even have to bother your physician (in the US). Like all medications, it will have risks as well as benefits, and I'm not qualified to comment on the balance between them. But I suppose I will probably get it when I get to that age, assuming no serious problems have shown up in the mean time. --Trovatore (talk) 22:30, 31 May 2011 (UTC)[reply]

Both of these are discussed in the article (from a community health POV):

Nil Einne (talk) 05:42, 1 June 2011 (UTC)[reply]

I was unfamiliar with this myself. The papers I have been doing does not explain the nomenclature of diastereomers, except for cis and trans isomers. What about all these strange ones I find on the internet: allo-, myo-, scyllo-, chiro-, etc. What do they mean, what are their requisites? I tried googling for a definition, I tried my textbooks, no answer therein. Plasmic Physics (talk) 13:48, 31 May 2011 (UTC)[reply]

have you tried [7] or [8]? --Stone (talk) 18:33, 31 May 2011 (UTC)[reply]

A quick search for "scyllo-" led me to [9] - apparently, this is a system for cyclic diastereoisomers by H.G. Fletcher, L. Anderson, and Henry A. Lardy, J Org Chem 16, 1238 (1951). There are eight prefixes allo, cis, DL, epi, muco, myo, neo, and scyllo for the inositol configurations and ten prefixes allo, cis, epi, gala, muco, neo, proto, scyllo, talo, and vibo for the quercitol configurations. There's a table in the Google Books link explaining them as follows: (warning: typos possible)

Meso diastereomers
quercitol	fractional notation	inositol
cis	12345	1-deoxy-cis
muco	1245/3	3-deoxy-muco
neo	15/234	2-deoxy-neo
scyllo	135/24	1-deoxy-scyllo
Active or Racemic diastereomers
allo	1234/5	5-deoxy-allo
epi	1235/4	2-deoxy-epi
gala	125/34	2-deoxy-allo
proto	134/25	2-deoxy-dextro
vibo	124/35	1-deoxy-myo
talo	123/45	1-deoxy-neo

The second column numbers indicate OH up/OH down. If the lowest numbered group (usually 1) is up, it is L-enantiomer; down is D-enantiomer. The source gives some optical rotation data for the active forms (zero for the others and DL mixtures, by experiment). Note that position 6 in quercitol has no -OH (the only difference from inositol), which establishes the plane of symmetry: when 3, 24, or 234 are the odd groups out, the result is a mirror plane and hence no optical activity. By contrast inositol so happens to have only one form capable of chiral D and L forms (as shown in the first link in Stone's entry), which is the chiro- form.

Among these famous compounds are myo-inositol, the usual biological form, and scyllo-inositol, currently under investigation for Alzheimer disease. Wnt (talk) 18:46, 31 May 2011 (UTC)[reply]

OK, that be useful, but what about a more general description? I've seen some of those term used on other cyclic compounds, like 2-(aminomethyl)cyclopropane-1-carboxylic acid. Plasmic Physics (talk) 23:15, 31 May 2011 (UTC)[reply]

I think your table is back to front, deoxy means without hydroxy. Quercitol is without a hydroxy group, so what'sgoing on there? Plasmic Physics (talk) 08:45, 1 June 2011 (UTC)[reply]

cis-quercitol = 1-deoxy-cis-inositol, etc. The same compound is described by both names, but deoxy-inositol = quercitol. Wnt (talk) 17:28, 1 June 2011 (UTC)[reply]

OK, so what about the previous question? Plasmic Physics (talk) 01:10, 2 June 2011 (UTC)[reply]

I have a question on the exact name of a unknown ladybug/ladybird, I made images from the larva, the pupal and the fresh bug. The images were taken in Göttingen in the centre of Germany beneath a tilia tree were thousands of those little larva fed on the aphids. Funny to watch that the pupal lift their back from the tree and after a vibration they go back flat on the tree.--Stone (talk) 13:46, 31 May 2011 (UTC)[reply]

If they are present in very high densities, Asian_lady_beetle is a good bet. Note that high-confidence species-level ID of insects is quite hard; you can't be certain unless you take a specimen to an entomologist, or work through a good taxonomic key yourself. (Learning how to use an insect ID key is itself no minor task.) SemanticMantis (talk) 14:17, 31 May 2011 (UTC)[reply]

I would agree that the lower photographs definitely show the larva and pupa of Harmonia axyridis, here in the UK most commonly called the Harlequin ladybird. The upper picture of a black ladydird with red spots could be a Pine Ladybird (Exochomus quadripustulatus). Richard Avery (talk) 19:03, 31 May 2011 (UTC)[reply]

Thanks! The black bug is also from the same larva and pupa, they were looking all the same and looking for several days I saw only one gray larva not looking like the thousand others. So it is a black form of the Harmonia axyridis, how boring! I will try to get another! --Stone (talk) 20:27, 31 May 2011 (UTC)[reply]

File:Centipede floor.JPG

We are getting a couple of these a day in our house. They are some sort of centipede or millipede (they look like Narceus americanus). They are large - 9 to 10 cm long. When we find them they are usually leaving the area of two of the doors opening to the outside, making me think that they are getting in through the doors.

Any thoughts on how we can get rid of them or keep them out of the house? Bubba73 ^{You talkin' to me?} 19:55, 31 May 2011 (UTC)[reply]

By the way, its a millipede. --Chemicalinterest (talk) 20:37, 31 May 2011 (UTC)[reply]

Try Borax first. Google around for suggestions. In these days of insecticides, borax is often over-looked. PS. Why don't you like god's little creatures? They recycle organic matter.--Aspro (talk) 21:23, 31 May 2011 (UTC)[reply]

Well they probably won't get much organic matter in our house. If they would stay out, I'd leave them alone. Bubba73 ^{You talkin' to me?} 22:32, 31 May 2011 (UTC)[reply]

Sounds like you haven't got them properly toilet trained.--Aspro (talk) 22:38, 31 May 2011 (UTC)[reply]

I've had that happen once at my parent's house. It's a temporary population explosion, it only took until the begining of fall that they died back off. They don't really spread disease or anything, so if you're willing to wait, I'd go with that. Borax, as reccomended above, is a moderate risk to children and pets, so keep that in mind if you use it. i kan reed (talk) 21:31, 31 May 2011 (UTC)[reply]

(ec)Do cats not eat those things? Just thinking of my mother's cat - he always stalks bugs and creepy-crawlies around the house (only time he ever shows anything approaching courage). --Kurt Shaped Box (talk) 22:36, 31 May 2011 (UTC)[reply]

They are somewhat toxic — see millipede#Defense mechanisms. From the description there it doesn't sound like it would actually kill the cat (though who knows) but he might well learn to leave them alone. --Trovatore (talk) 23:32, 31 May 2011 (UTC)[reply]

Wikimedia Commons is short of images of these critters. Can someone help Bubba with uploading images and selecting the right licence. Oh. Don't it look cute? --Aspro (talk) 22:35, 31 May 2011 (UTC)[reply]

I just did the license thing. I just took a quick shot to identify it. If you want a better one, I can probably get a better one. Bubba73 ^{You talkin' to me?} 22:48, 31 May 2011 (UTC)[reply]

I need to change the description of you want to keep the photo. It looks like a Narceus americanus and fits the description, but I can't be sure. Bubba73 ^{You talkin' to me?} 22:54, 31 May 2011 (UTC)[reply]

If you want to keep it, I need to rename it too. Notice how it shows that their legs move in waves. Bubba73 ^{You talkin' to me?} 23:07, 31 May 2011 (UTC)[reply]

Try to recreate Arthropleura by selectively breeding them in a high oxygen environment. Count Iblis (talk) 23:19, 31 May 2011 (UTC)[reply]

Why is it that a radio antenna that is bent into a fractal shape receives more bands than one that is not? --71.204.251.178 (talk) 23:38, 31 May 2011 (UTC)[reply]

Fractal antenna#Fractal antennas, frequency invariance, and Maxwell's equations explains it a little bit. That section also points to this paper, which probably answers your question fairly thoroughly, but unfortunately isn't free to read. Red Act (talk) 23:56, 31 May 2011 (UTC)[reply]

The explanation I heard is that a single fractal antenna can handle all frequencies needed, so can be bigger (and thus better) than the several smaller antennae needed to do this with non-fractal shapes, and yet still fit in the same space. StuRat (talk) 00:36, 1 June 2011 (UTC)[reply]

On the contrary, I thought a smaller fractal aerial would pick up much more signal than a conventional aerial of similar size. That is why mobile/cell phones now have tiny fractal aerials hidden inside them rather than a telescopic external one. I wish it were possible to buy a fractal aerial cheaply as I'd like to plug them in to my radios, but I expect they are covered by patents. 2.97.220.135 (talk) 15:18, 2 June 2011 (UTC)[reply]

Thus is in regards to the recent suggestions that cellphones may cause cancer. How can microwaves, which carry less energy than visible light, nonetheless cause more damage to human tissue? — Preceding unsigned comment added by 65.92.5.252 (talk) 23:45, 31 May 2011 (UTC)[reply]

Probably because they penetrate further. Light and UV do damage the skin, but mostly on the surface, which is soon shed, thus limiting the accumulation of damage. StuRat (talk) 00:33, 1 June 2011 (UTC)[reply]

Melanoma begs to differ. Microwaves do damage in different ways than visible, or especially UV light. In any case, as the article Mobile phone radiation and health points out, mobile phone radiation is classified as a Group 2B carcinogen ("possibly carcinogenic to humans"), while ultraviolet radiation is in Group 2A ("probably carcinogenic to humans"). Even if microwave radiation has a carcinogenic effect in humans, it's obviously quite small, wheras ultraviolet radiation has been strongly linked to skin cancer for decades. Buddy431 (talk) 01:22, 1 June 2011 (UTC)[reply]

The fact that most of it is prevented doesn't mean it never occurs. If skin was never shed, the problem would be far worse. StuRat (talk) 03:51, 1 June 2011 (UTC)[reply]

Anyone who is familiar with absorption spectroscopy would know that a large range of chemical moeties tend absorb in the infrared range, in particular the hydrogen-oxygen group as is present in water. Absorption of EMR by molecules is analogueous to spray painting over a stencil. It doesn't matter how much pressure you use, the paint will still only go where the stencil allows it to go. It doesn't matter how energetic the EMR is, the molecule will only absorb at a specific signiture of energies. That's why a microwave oven is so good at what it does. Plasmic Physics (talk) 02:53, 1 June 2011 (UTC)[reply]

Of course, when they absorb in the IR region, the molecules vibrate faster, heating up (like a microwave oven). They don't, however, have any electronic transitions. UV radiation, on the other hand, will cause electronic changes: it is ionizing radiation, and will create Free Radicals, which can be very bad from the cancer-causing standpoint. The mechanism by which cell-phone microwaves cause cancer (if they do at all - despite the WHO reclassification, the current evidence shows that the correlation between cell phone usage and Glioma, even if genuine, is small) is less well understood. Buddy431 (talk) 03:53, 1 June 2011 (UTC)[reply]

You're asking for a plausible theoretical mechanism by which cell phone radiation could cause cancer. The answer is that there is no plausible theoretical mechanism. And the experimental support is underwhelming at this point. This places cell-phone-induced cancer in the same category as power-line-induced cancer, psi powers, etc. -- BenRG (talk) 06:16, 1 June 2011 (UTC)[reply]

This article might be relevant as to the difference. The UN's dealing with this one. Grandiose (me, talk, contribs) 13:01, 1 June 2011 (UTC)[reply]

Here's the actual press release from the WHO that provoked the current round of news stories. The press release says that "A concise report summarizing the main conclusions of the IARC Working Group [...] will be published in The Lancet Oncology". This is not a new study; it is a new discussion of old data, data which is described in the press release as "limited" and "inadequate". Their decision to change the classification to 2B means that they think that further study is justified. Anything beyond that that you may have read was an invention of clueless reporters.

I agree with P.Z. Myers's reaction to this. (edit: Also, Orac's reaction is worth reading in its entirety.)

One of the reasons I mentioned psi powers is that parapsychological research was conducted at (and funded by) a number of prestigious universities including Stanford, Duke and Princeton, over a period of decades. Some studies found large deviations from randomness. Those studies turned out to be methodologically flawed or downright fraudulent. The AAAS still recognizes parapsychology as a science after all these years. Completely nonexistent phenomena can get a lot of legitimacy, for a while. -- BenRG (talk) 20:21, 1 June 2011 (UTC)[reply]

Who says microwaves carry less energy than visible light? Cuddlyable3 (talk) 12:51, 1 June 2011 (UTC)[reply]

You may have heard of a famous fellow called Max Planck, he says so. Plasmic Physics (talk) 13:09, 1 June 2011 (UTC)[reply]

Strictly speaking, this should be qualified - microwaves carry less energy per photon than visible light. As has been pointed out, that is not the only factor that needs to be taken into account here. You can't cook a microwave dinner by leaving it outside on a sunny day (unless you have one of these). Gandalf61 (talk) 14:49, 1 June 2011 (UTC)[reply]

I think the evidence for a link is extremely weak. One also has to take into account here that medical science is not a hard science. quite definite statements will sometimes be made, even if by the standards of the hard sciences, there isn't the evidence to support that. Take e.g. the much easier to investigate case of the relation between exposure to radioactivity and cancer. Even in that case, medical science has completely failed as pointed out here. Count Iblis (talk) 15:20, 1 June 2011 (UTC)[reply]

In the context of terahertz, I have read claims that twisting and stretching motions in the DNA could absorb in these frequencies. I remember seeing an article about an Army-funded study in which people were looking for specific absorptions from anthrax spores in the air to identify the species; they published 1/40 of the spectrum they intended to survey, citing a negative result. The military/terrorist importance of such research - for example, to identify the DNA of one person in a city from the air and to cause him (only) to develop a specific form leukemia - cannot be overemphasized. This is what makes nuclear weapons obsolete. Wnt (talk) 21:05, 1 June 2011 (UTC)[reply]

Huh? How would being able to target individual people for cancer make nuclear weapons obsolete? --Mr.98 (talk) 00:47, 2 June 2011 (UTC)[reply]

Op here: did the WHO try to rule out other possible explanations for a correlation between cell phone use and cancer (e.g. consumer habits)? 65.92.5.252 (talk) 03:40, 2 June 2011 (UTC)[reply]

In this article, it states that an excess of bromine prevents the formation of phosphorus pentabromide. How can that be? --Chemicalinterest (talk) 00:46, 1 June 2011 (UTC)[reply]

There's a reference in that article for that statement. Did you follow it? --Jayron32 02:58, 1 June 2011 (UTC)[reply]

The reference is not publicly available. By the way, it says the opposite here. --Chemicalinterest (talk) 12:42, 2 June 2011 (UTC)[reply]

That's a clone of an older version of our own page:) I have access to the cited article, which states "a slight excess of...phosphorus", so I undid this unexplained change. DMacks (talk) 15:46, 2 June 2011 (UTC)[reply]

I can't find a good ref for modern preparation of Phosphorus pentabromide, but did find a ref that the obvious one suggested here tends to lead to PBr7 (!) at least under some conditions. DMacks (talk) 16:00, 2 June 2011 (UTC)[reply]

So it was one of those random fact changers changing the article. PBr5 is more likely to form in high bromine concentration than PBr3 for obvious reasons. --98.221.179.18 (talk) 19:40, 2 June 2011 (UTC)[reply]

No I'm not talking about the 120V/240V transformers. I know what those are and they are usually grey and for power lines. I am wondering what are those cylinders on the lower wires. Usually Telephone and Cable wires. Here's a picture that shows about 4-6 of them.

http://ops.fhwa.dot.gov/publications/telecomm_handbook/images/fig8-5.jpg — Preceding unsigned comment added by 76.184.70.229 (talk) 05:09, 1 June 2011 (UTC)[reply]

I'm not sure what the real name for them is, but "distribution box" might be close. They're places that allow fat cables to be tapped to drop small cable pairs (these days two of them) to individual users. PhGustaf (talk) 05:18, 1 June 2011 (UTC)[reply]

this website has heaps of info, I think the answer is they are amplifiers and splitters. Vespine (talk) 05:27, 1 June 2011 (UTC)[reply]

Breakout boxes. Cuddlyable3 (talk) 12:48, 1 June 2011 (UTC)[reply]

If one does not like "artificial" calendars, one can give the date simply by counting days since the most recent equinox. Today's date (June 1) in such a system would simply be "73" (or "252" if you prefer the September equinox), give or take a day depending on timezone.

I do not understand why pretty much all year-numbering systems are so anthropocentric and "artificial". The Jalaali calendar at least tries not to be so artificial in its days and months, but the year numbering is rather religious and anthropocentric.

Year numbering systems need not be so anthropocentric; just as I counted days of the year from an equinox, one can count years of the Great Year from a year whose winter "half" and summer "half" are of equal length. So... using this system, today (2011-06-01) is day 73 of year ???? — Preceding unsigned comment added by 75.40.137.207 (talk) 06:17, 1 June 2011 (UTC)[reply]

According top our article, "In reality the exact duration cannot be given, as the rate of precession is changing over time." So, we need something more precise. Also, the precession of the equinoxes doesn't really have a "start" point from which we can measure. Might I suggest an astronomic phenomenon for which we do have a precise date ? How about the supernova SN 1006, first observed on Earth in the year 1006 AD (under our present deficient calendar system) ? StuRat (talk) 07:32, 1 June 2011 (UTC)[reply]

If I understand your question, you want to know when the last time an equinox occurred at perihelion? This would correspond to Spring + Summer having the same duration as Fall + Winter. According to the orbital dynamics reference model I have on my computer, that last occurred in the year 4025 BC. The reference model is intended to be used for calculating insolation changes over hundreds of thousands of years, so I'm not sure how much precision one should regard that date as actually having. So, assuming I understood your question correctly, the answer is about 6000 years ago. Dragons flight (talk) 08:44, 1 June 2011 (UTC)[reply]

That starts a year count consistent with Young Earth creationism. Cuddlyable3 (talk) 12:43, 1 June 2011 (UTC)[reply]

So it looks like my answer is 6114 (or maybe 6113). Thank you! — Preceding unsigned comment added by 75.40.137.207 (talk) 13:49, 1 June 2011 (UTC)[reply]

... or perhaps I should use 17072. — Preceding unsigned comment added by 75.40.137.207 (talk) 14:00, 1 June 2011 (UTC)[reply]

Since humans invented the calendar and are the only ones who care about it, why wouldn't it be "anthropocentric"? ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:35, 2 June 2011 (UTC)[reply]

Is pound-mass (lbm) a real unit or something derived or obfuscated?

Is it only relevant if you're on the surface of the Earth?

What is the conversion of kg to lbm if you are on the moon?

What is the difference between pound-mass and pound-force (from their respective articles I can only surmise that they are the the same as long as you're on the surface of the Earth)?

What is the difference between pound-mass and slugs? What about "poundal" (before Wikipedia I never heard of this one)?

At uni (aerospace engineering) I was taught to use slugs as imperial mass and treat pounds as a force. Is this right or have I misunderstood?

Anyone answering this please don't treat me like an idiot and please call a spade a spade WP:SPADE. If the answers were obvious there would be no common misconceptions about pounds being a force/mass and how to convert between them etc. Sometimes it just takes someone to explain something in a different way for it to sink in, and for me (and others I think) that explanation hasn't been found.

Relevant articles are Pound-force and Pound-mass. I tried to clear up some of this in the Pound-mass discussion page but was instructed to take my questions here. The Pound-mass article doesn't really mention much about its relationship with the Pound-force or slug (a unit of mass used in aerospace engineering). As an engineer I'm always converting between mass and force, but the conversion table at Pound-force only converts force to force, and my discussion on the Pound-mass talk page led to my shame for converting between units.

Can anyone present real world examples of conversion between these units (mass and force, under influence of gravity of earth and moon just for comparison)?

Thankyou in advance to anyone able to help. — Preceding unsigned comment added by 203.129.23.146 (talk) 09:10, 1 June 2011 (UTC)[reply]

Think of pounds-force and pounds-mass as entirely separate and unrelated units, from a physics point of view, where the ratio between them just happens, by a stunning coincidence, to equal the acceleration of gravity at sea level on the Earth (at some specified latitude I suppose, but I'm not sure which one). That coincidence makes certain calculations easier but has nothing to do with the essence of the units. --Trovatore (talk) 09:20, 1 June 2011 (UTC)[reply]

The weight of an object is different at different locations in the universe. On the other hand, the mass of an object is the same, regardless of its location in the universe. The relationship between lbm, slugs and kg is the same on the Earth, the moon or anywhere else in the universe. It is the relationship between weight on Earth and weight on the moon that is the tricky one. If you treat slugs as imperial mass and pounds as a force you can't go wrong. All engineering students have this difficulty initially, but then it all falls into place when you realise that equations, such as F=ma, can only be correct if you use consistent units. lbm, poundals and ft.s^-2 are consistent units. So too are slugs, lbf and ft.s^-2; and kg, newtons and m.s^-2. Any mixture of those units won't be consistent and so will deliver an incorrect answer. Stick with it. Dolphin (t) 12:16, 1 June 2011 (UTC)[reply]

Imagine a lunar exploration vehicle with a mass of 100 kg. (Its mass is 100 kg on Earth, on the moon, and everywhere else.) On the Earth's surface the weight of this lunar exploration vehicle is 980 N. On the moon's surface its weight is only 160 N so an astronaut would be able to pick it up and maneuver it by hand. (Acceleration due to gravity on the moon's surface is only 1.62 m.s^-2, or 16.5% of that on the surface of the Earth.) Imagine some component of the lunar lander has a mass of 100 slugs. Its weight on the Earth's surface is 3,220 pound-force (lbf), but its weight on the moon is only 530 pound-force. Some other component of the lunar lander has a mass of 100 pound-mass (lbm). Its weight on the Earth's surface is 3,220 poundals, but its weight on the moon is only 530 poundals. (Acceleration due to gravity at the Earth's surface is about 9.8 m.s^-2 or 32.2 ft.s^-2.) Dolphin (t) 12:41, 1 June 2011 (UTC)[reply]

The component with a mass of 100 pound-mass has a weight of 100 pound-force on the Earth's surface, but on the moon its weight is only 16.5 pound-force. However, these aren't consistent units so applying a mass in lbm and an acceleration if ft.s^-2 in the equation F=ma won't give the answer in pound-force. The answer will be in poundals. Dolphin (t) 06:37, 2 June 2011 (UTC)[reply]

The important thing to remember is that the pound is (historically) a unit of weight (not force or mass). This can be extracted from the Pound (mass) article, but I agree the article could be more explicit on this point. From this definition, we get the pound mass (the mass that has a weight of one pound on the Earth's surface), and the pound force (the force that is equal to a pound (weight)). The slug and poundal come in when we want to avoid putting correction factors related to g in Newton's second law, and keep it as F = ma. Tevildo (talk) 13:01, 1 June 2011 (UTC)[reply]

I found this table helpful:

Three approaches to units of mass and force or weight^[1][2]

v t e Base	Force		Weight		Mass
2nd law of motion	m = ⁠F/a⁠		F = ⁠W ⋅ a/g⁠		F = m ⋅ a
System	BG	GM	EE	M	AE	CGS	MTS	SI
Acceleration (a)	ft/s2	m/s2	ft/s2	m/s2	ft/s2	Gal	m/s2	m/s2
Mass (m)	slug	hyl	pound-mass	kilogram	pound	gram	tonne	kilogram
Force (F), weight (W)	pound	kilopond	pound-force	kilopond	poundal	dyne	sthène	newton
Pressure (p)	pound per square inch	technical atmosphere	pound-force per square inch	standard atmosphere	poundal per square foot	barye	pieze	pascal

Essentially, pounds can be a unit of either mass or force (or both) depending on the system of units in which one is working. Like the original poster, I was taught (as a physicist) to treat pounds as a unit of force (weight) and use slugs as the corresponding mass unit. This is the FPS-Engineering unit system. It appears in practice, that the pound commonly used to sell products in the United States is usually a measure of mass, however, since scales in stores are checked by placing a reference standard on them and ensuring that the scale gives the correct "weight". Since a standard (of constant mass) is used to calibrate the scale rather than a constant-force standard, this makes the scale essentially a calibrated measurement of mass rather than force. --Srleffler (talk) 18:15, 1 June 2011 (UTC)[reply]

What is the structure of monoperoxoboric acid whose formula is [(HO)3B(OOH)] and the structure of sodium peroxoborate whose formula is Na2[B2(O2)2(OH)4].6H2O--Krishnashyam94 (talk) 11:51, 1 June 2011 (UTC)[reply]

I think you might have added one too many hydroxyl groups to the first formula. If corrected, it would be a derivative of boric acid, where one hydrogen is replaced with a hydroxyl group, forming hydroperoxyboronic acid, or monoperoxoboric acid as you call it. The structure of the second formula without the sodium would simply be a dimer of the hydroperoxyboronate anion. The dimer is held together through bridging of two hydroxyl groups in two three-center two-electron bonds. Plasmic Physics (talk) 14:07, 1 June 2011 (UTC)[reply]

Our Sodium perborate article does not agree. DMacks (talk) 15:28, 2 June 2011 (UTC)[reply]

...and now has ref to the xray structure supporting that it's peroxide bridges with normal bonding (no 3c-2e at all). DMacks (talk) 19:33, 2 June 2011 (UTC)[reply]

What is the cost of building a small particle accelerator? --999Zot (talk) 13:54, 1 June 2011 (UTC)[reply]

That's a very open-ended question. Here's a home-built cyclotron constructed as part of a (admittedly very advanced) high school science fair project. In a setup like that, the vacuum pumps will probably run in the hundreds of dollars (purchased used), and likely account for the lion's share of the cost. He reports particle energies up to about 100 keV, which isn't really 'atom-smashing' territory, but is definitely solid proof of principle. From there, the sky's the limit. TenOfAllTrades(talk) 14:26, 1 June 2011 (UTC)[reply]

An historical note: Ernest Lawrence built the first (80 eV) cyclotron for $25, in 1931 dollars (around $350 in modern currency). --Mr.98 (talk) 15:02, 1 June 2011 (UTC)[reply]

On this page is an alignment of a gene for multiple animals - I would like each of those genomic sequences, preferably with exons and introns distinct by appropriate capitalisation, in a file that I can then stuff into my alignment program to make a diagram to stick in my report and presentation for people to gawk at. What's the most efficient way? I don't really want to copy and paste individual sequences. --129.215.47.59 (talk) 14:52, 1 June 2011 (UTC)[reply]

What program do you want to put it into? Looking at this I'm thinking that a basic Perl script might do well to process the data, but probably there is a better way. Wnt (talk) 18:09, 1 June 2011 (UTC)[reply]

Lasergene SeqBuilder and MegAlign, but it should be possible to have the sequences in generic formats which most DNA sequence programs can handle? Ensemble doesn't provide a mass export feature for the gene sequences it holds? Isn't it a kind of "must have" feature? --129.215.47.59 (talk) 20:16, 1 June 2011 (UTC)[reply]

I'm confused about quantum mechanics. Postulates of quantum mechanics states that "We can also show that the possible values of the observable A in any state must belong to the spectrum of A." So if the observable for the position on the x axis is x then the "values" of that observable have to be eigenvalues. Let a be one of those eigenvalues, then ${\displaystyle x\psi (x,y,z,t)=a\psi (x,y,z,t)}$ which is only possible if ${\displaystyle \psi }$ is identically zero. Now where exactly is my error? 93.132.161.170 (talk) 18:05, 1 June 2011 (UTC)[reply]

In an infinite dimensional vector space such as the Hilbert space of quantum mechanics, spectrum and eigenvalues are not exactly the same thing, although they are closely related. The "eigenfunctions" for the position observable are Dirac delta functions, ${\displaystyle \psi (x)=\delta (x-a)}$ (I have omitted the other dimensions for simplicity). Looie496 (talk) 18:19, 1 June 2011 (UTC)[reply]

Yes, that's it. In my mind I was always restricted to think only of continuous functions. But with the Dirac delta, it is even an eigenvalue/eigenvector. Thanks a a lot. 93.132.161.170 (talk) 19:00, 1 June 2011 (UTC)[reply]

Ouch, I was still confused, ${\displaystyle \delta (0)=\infty }$, not 1, so this is why it is no eigenvalue and the spectral values come in. 93.132.161.170 (talk) 19:47, 1 June 2011 (UTC)[reply]

Can't help it, the more I think about it the more I get confused again. Could you tell how the Hilbert space and the scalar product are defined in this case? I started trying to understand why a should be a spectral value of x and found I can not do that as long as I don't know "what tricks are allowed", in other words, what the elements of that Hilbert space really are. 93.132.161.170 (talk) 20:28, 1 June 2011 (UTC)[reply]

And now I can cast my confusion into a question again: I understand that ${\displaystyle \langle f,g\rangle }$ is defined as ${\displaystyle \int f(x)\cdot g(x)\,dx}$ (for some kind of integral). Now to avoid confusion with the Dirac delta let's denote the Kronecker delta by ${\displaystyle \kappa }$. Then ${\displaystyle \langle \kappa ,\kappa \rangle =0}$ and thus in this Hilbert space, ${\displaystyle \kappa }$ would be in the same equivalence class as the constant zero function. Now compute ${\displaystyle \langle \delta ,f-f(0)\kappa \rangle }$. This would be zero because the right function is zero at point zero. On the other hand, ${\displaystyle \langle \delta ,f-f(0)\kappa \rangle =\langle \delta ,f\rangle -f(0)\langle \delta ,\kappa \rangle }$ and that would be f(0) as ${\displaystyle \langle \delta ,\kappa \rangle =0}$ because ${\displaystyle \kappa }$ is in the same equivalence class as zero. If I don't have an error elsewhere in the computation, I guess I can either use the Dirac delta, picking a point value from a "function" (element of the Hilbert space in question) or I can have a positive definite scalar product defined by integration that ignores point values, but not both at the same time. 93.132.161.170 (talk) 21:05, 1 June 2011 (UTC)[reply]

Are you sure that ${\displaystyle \langle \kappa ,\kappa \rangle =0}$ is correct?

Pretty sure. ${\displaystyle 0\leq \langle \kappa ,\kappa \rangle =\int _{-\epsilon }^{\epsilon }\kappa ^{2}(x)\,dx\leq 2\epsilon }$ for arbitrarily small ${\displaystyle \epsilon }$. If you don't hold with non-standard analysis that only leaves the possibility that the product is zero. To clarify, ${\displaystyle \kappa (x):={\begin{cases}1,&x=0\\0,&x\neq 0.\end{cases}}}$. Might be the product is defined differently; if so, this is part of my question. 93.132.161.170 (talk) 22:52, 1 June 2011 (UTC)[reply]

I don't see what you are trying to do here. The Kronecker delta, defined thus as a function, is utterly useless. My recommendation is to find a basic graduate-level textbook on quantum mechanics -- this stuff is too intricate to learn from a Wikipedia article or Reference Desk. Looie496 (talk) 23:02, 1 June 2011 (UTC)[reply]

What I did is (if correct) a proof that contradicts the premisses (as I have understood). The Kronecker delta is useful here to construct the function ${\displaystyle f-f(0)\kappa }$ that has point value zero at x=0. So I assume, my premisses (picked from wikipedia) are wrong. 93.132.161.170 (talk) 23:12, 1 June 2011 (UTC)[reply]

The point you are making is correct; the source of the problem is that the way the Dirac delta function is used is physics is not rigorous (the whole concept of the delta functiuon is not rigorous, it has to be defined as a distribution). Then, the position representation should be used with care, in the usual Hilbert space formalism, you can't define it in a 100% rigorous way. You need to work in a rigged Hilbert space to do that.

Now, you can get around these problems by considering position eigenstates |x> to be the limiting cases of physical states that have a finite spread in position. If you formally take the limit at the end of all computations, you never get problems. This is from a physics point of view better because in reality, you can't locate a particle at a precise position. Count Iblis (talk) 23:48, 1 June 2011 (UTC)[reply]

So if I understand you correctly, there is nothing wrong with the postulates but for the usual use of a function space there is trouble having an operator for the position. To get around this, either a more complex Hilbert space is used to handle it strictly correct or (more often, I assume) the Dirac delta is used in the sense of "yes, I know, but all is well because I will take the limit later" just as we multiply and divide by dx (promissing to take the limit later) ? 95.112.146.231 (talk) 00:11, 2 June 2011 (UTC)[reply]

That's right. Typically, you encounter delta functions, not because of working in position representation, but because you work in an infinite volume and then you need to use the delta function normalization. To avoid this, you can put the whole system in a finite volume (which makes momentum discrete instead of continuous), do all the computations with square integrable functions and then take the V to infinity limit at the end. Count Iblis (talk) 01:08, 2 June 2011 (UTC)[reply]

And the Kronecker delta is used to deal with the discrete variables which may come up such as the momentum of a particle in a box example given by Count Iblis above. For such cases the product is defined in terms of a sum - not an integral, and you have ${\displaystyle \langle \kappa ,\kappa \rangle =\sum _{i}\kappa (i)^{2}=1\neq 0}$. Dauto (talk) 03:11, 2 June 2011 (UTC)[reply]

Is there any textbook on quantum mechanics that explicitly describes what Hilbert space it is using without the reader having to guess from intuition? As seen above, you can virtually "proof" anything if you got the wrong one. 95.112.146.231 (talk) 10:02, 2 June 2011 (UTC)[reply]

Yes, there are such textbooks, typically written for mathematics students. However, you then have to first master the theory of distributions and functional analysis, the prerequisite knowledge is topology and measure theory. I have a book on functional analysis (I don't have it with me right now, I don't remember the title and authors) that has a chapter of quantum mechanics. But, in theoretical physics, we don't teach students by being that rigorous. Students learn quantum mechanics when they have barely mastered linear algebra. And if you want to make progress in theoretical physics, you'd better get used to that, because you won't get the chance to rigorously learn differential geometry before you have to do your General Relativity exam, learn the rigorous mathematical foundations of quantum field theory before it is exam time for that subject.

I therefore think that this book is better for you. I learned QM from that book because I wasn't satisfied with my university textbook. It is considered by many to be the best book on QM ever written. Count Iblis (talk) 15:39, 2 June 2011 (UTC)[reply]

What you say sheds a light on it. So I'm coming in from the "wrong end". I have studied mathematics (but forgot nearly all of it as I didn't have any use or practice for it in the last 20 years). I still have the books (albeit I have to search where I stashed them). Rigorous measure theory is great, especially if you have got sick with "definitions" of probability that go along lines as "tossing a coin very often will finally ...". 95.112.146.231 (talk) 16:55, 2 June 2011 (UTC)[reply]

How can I visually tell rye from wheat? 75.138.213.213 (talk) 22:48, 1 June 2011 (UTC)[reply]

Plant? Seed? Flour? Looie496 (talk) 23:03, 1 June 2011 (UTC)[reply]

Bread? Red Act (talk) 00:09, 2 June 2011 (UTC)[reply]

Beer? 95.112.146.231 (talk) 00:14, 2 June 2011 (UTC) difference-between-wheat-and-rye[reply]

Whisky? SemanticMantis (talk) 14:25, 2 June 2011 (UTC)[reply]

Hello. So today I was walking out to my boat, and I encountered a snake. I didn't see it at first...I HEARD it. I turned to find a rather large snake (perhaps 1.5-2 meters), brownish/green in color, with a kind of "blurred" diamond pattern (I don't know if "diamond" is a good description, but it had a discernible pattern). Anyway, its head was raised into the striking position, and its tail was erect and shaking vigorously, producing the "rattling" sound. My first instinct (aside from jumping ten feet) was that it was a rattle snake. But when I moved away, the snake slithered of the rocks into the water. It didn't seem very graceful in the water, rather just sort of coiled up and floated, all the while hissing and shaking its tail. It was then, when I could get a good close look at him, that I realized the "rattling" sound had stopped. Despite continuing to shake its tail like a rattle snake, it did not have any visible "rattles." I am very certain of this point. The sound I had heard, I gathered, was from the tail shaking amongst the nearby grass and weeds it was hiding in before going into the water. So, my question is, are there snakes that will mimic the characteristics of a rattle snake as a defense mechanism? Is this common? Any articles you can point me to? Also, do snakes have "nests" that they defend. (This one seemed particularly protective of the area, which is why I think it moved into the water...to get away from us, but still stay near.) And can a snake strike or bite while on top of, and, separately, while swimming underneath the water? (This last part is a question my son had. We didn't see this snake actually swim "underneath" the water, but we have seem some snakes, such as water moccasins, exhibit this sort of aquatic behavior.) I am in the Southeastern U.S. near a large freshwater lake, if it matters. Sorry for the long post. Thanks, Quinn ^{❀ BEAUTIFUL DAY} 04:20, 2 June 2011 (UTC)[reply]

Looking at Venomous snake led me to Crotalus adamanteus, the eastern diamondback, which sounds like it could be your snake, as it hangs around in marshes and can swim. It's possible it lost its rattle somewhere along the way but still "rattles" instinctively. Do the pictures in that article look anything like your snake? ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:33, 2 June 2011 (UTC)[reply]

As for the rattling stopping when it went in the water, that sounds like what I would expect. The rattle is a series of loose scales that strike one another when shaken. If they have water between them, that would dampen the sound considerably. StuRat (talk) 07:07, 2 June 2011 (UTC)[reply]

And, in case it isn't obvious, BACK AWAY FROM THE SNAKE. Our article lists a "mortality rate of 30%" for those bitten, so don't play Russian roulette by hanging around it. StuRat (talk) 07:11, 2 June 2011 (UTC)[reply]

There are several harmless snakes that mimic the rattle of a true rattlesnake, among them the corn snake and kingsnakes. As the corn snake article mentions, they're hugely variable in colour and patterning, so it could well have been one of them. While the old saw about telling whether a snake is venomous by the shape of the head is largely bunk, rattlers do tend to have a rather broad flat head in comparison to corns and kings and also tend to have a stockier body, though that will vary more with how successful the hunting has been. Matt Deres (talk) 14:07, 2 June 2011 (UTC)[reply]

Wow, yes! I do believe it was a corn snake. Thanks! And upon reflection last night, I wonder if we had "cornered" him against the water, which would explain his aggressive behavior. Quinn ^{❀ BEAUTIFUL DAY} 16:25, 2 June 2011 (UTC)[reply]

What are examples of tropical cyclone names that were retired after just a single use? This includes North Atlantic hurricanes, Western Pacific typhoons, Eastern and Central North Pacific hurricanes, South Pacific and Australian region tropical cyclones, but does not include North Indian Ocean or Southwest Indian Ocean tropical cyclones or cyclones that form between the equator and 10°S and between 141°E and 160°E in the Australian region as their names are retired after a single use anyway (although in the North Indian Ocean once all the names have been used they will create a new list while in the Southwest Indian Ocean a new name list is used every year so they are technically not retirements). Narutolovehinata5 ^tccsdnew 09:19, 2 June 2011 (UTC)[reply]

I can't help you with the "one use" part, but you can find an extensive list of retired cyclone names here. Looie496 (talk) 17:38, 2 June 2011 (UTC)[reply]

How serious is to find E. Coli on your salad? (I don't mean the deadly strain, but simply trifle E. Coli). — Preceding unsigned comment added by 80.26.37.77 (talk) 17:22, 2 June 2011 (UTC)[reply]

As for the EC alone, there would be nothing to worry about, because you already have a lot in your guts. On the other hand, when you start to wonder on how it might have got there, you cannot exclude that someone or something has dumped on your salad, probably leaving more than just EC there. That's to say, it indicates some hygienic deficits. 95.112.146.231 (talk) 17:51, 2 June 2011 (UTC)[reply]

You wouldn't "find it on your salad" because it's a bacterium and you can't see them without a microscope. There are hundreds if not thousands of varieties of E.coli, most of which could be fatal in the right circumstances. The first you'd know about ingesting it is you'd be sick. I have to disagree with 95.112, though. Yes you do have E.coli in your guts and that's where it should stay. If it gets into the upper digestive tract you will have problems, of which vomiting is but the first sign. --TammyMoet (talk) 18:08, 2 June 2011 (UTC)[reply]

This is more about quantity and type than about presence per se. With the exception of a sterilized surgical theater, pretty much every surface in the world contains some quantity of E. coli. Problems arise when you have (a) a lot of it, or (b) a particularly pathogenic strain. Looie496 (talk) 18:23, 2 June 2011 (UTC)[reply]

Waiter, waiter! What are these things jumping in my salad? These are vitamins. And why are they jumping? This is because they are so healthy! 95.112.146.231 (talk) 18:32, 2 June 2011 (UTC)[reply]

How does the poison get to the kidneys? On my understanding, EC is a normal inhabitant of the intestine and the poison is a protein. Proteins are digested, that's what the bowls are for, and this poses a major problem on the Route of administration for drugs that consist of proteins but should not be digested. If the poison was just excreted into the liquids of the gut, a drastic laxative would do the trick. Some doctors are tight, but not all, so if that would work it would be known by now. 95.112.146.231 (talk) 18:20, 2 June 2011 (UTC)[reply]

See Shiga-like toxin. The protein binds to cells in the gut lining specifically (humans, but not cows) and actually mechanically creates little invaginations, which break off inside the cell. Wnt (talk) 19:36, 2 June 2011 (UTC)[reply]

When a vaccine is administered and successfully confers resistance, how is the pathogenic material "remembered" by the immune system? I've read Vaccine#Developing_immunity, which doesn't offer any explanation. My understanding is that the vaccine induces production of specific antibodies, but my question is more about the mechanism. Specifically, are different genes being expressed after vaccination? If so, is it fair to say that (some) vaccines trigger epigenetic effects? (I am not seeking any form of medical advice.) SemanticMantis (talk) 18:38, 2 June 2011 (UTC)[reply]

As far as I remember, some kind of leukocytes are actively mutating their genes expressing the antibodies. Those with "matching" antibodies are selected to survive. I would greatly appreciate if someone closer to the subject could check if what I memorize is correct and give more details. 95.112.146.231 (talk) 19:02, 2 June 2011 (UTC)[reply]

Active_immunity#Immunological_memory is the most detailed article I can find. It doesn't say much about the mechanism of the memory (how the immune system knows which patterns should be remembered). DMacks (talk) 19:09, 2 June 2011 (UTC)[reply]

The immune system contains a vast number of B cells which randomly produce different antibodies. Those that recognize "self" are deleted, but those that recognize specific pathogens are expanded exponentially. Vaccines use antigenic parts of viruses in combination with an adjuvant to make something the immune system will respond to by amplifying up the appropriate B cells, but it is still a difficult thing to do, and doesn't always work in every vaccinated person. (I was just reading that flu vaccine only produces immunity 70% of the time...) The B cells do the immune system's "R&D", and when activated they produce a large clone of cells which includes "large-scale manufacturing" called plasma cells; some are also set aside as memory B cells, a sort of "information archive". Wnt (talk) 19:46, 2 June 2011 (UTC)[reply]

If the gravitational "constant" changes would this reveal that the force of gravity is growing stronger in proportion to the product of 2 masses divided by the distance between them squared by indicating that the distance between masses is growing smaller or that mass is increasing in value or both? I am asking because the implication of this circumstance is that space is not expanding but that matter is simply increasing in density. Please correct me (after some thought) if you feel my hypothesis is wrong. --DeeperQA (talk) 18:47, 2 June 2011 (UTC)[reply]

I'm having difficulty trying to parse your first sentence. I generally overlook simple grammar errors in questions, but in this case I can't figure out what it is that you're intending your first sentence to mean. Could you perhaps rephrase it? Red Act (talk) 19:13, 2 June 2011 (UTC)[reply]

Geez... I am having difficulty myself... Sorry for not double checking the grammar after doing some inline editing while posting.. --DeeperQA (talk) 19:28, 2 June 2011 (UTC)[reply]

Newton's law of universal gravitation is

${\displaystyle F=G{\frac {m_{1}m_{2}}{r^{2}}}\ }$,

where:

• F is the force between the masses,
• G is the gravitational constant,
• m₁ is the first mass,
• m₂ is the second mass, and
• r is the distance between the masses.

You observe that the attractive force F can be changed by changing either of the masses or their separation r. The only way to show which of these has changed is by measuring it separately. The value of G can be measured and is as far as we know a constant. Over 200 years ago the first measurement of G found a value within 1% of today's value. Have you read the article Gravitation which notes present theories about gravity? Cuddlyable3 (talk) 19:20, 2 June 2011 (UTC)[reply]

Not recently but I will read it again... The time scale here I have in mind would be in billions of years rather than only 200 but I guess we are stuck with only that... --DeeperQA (talk) 19:33, 2 June 2011 (UTC)[reply]

How do they tell between a diamond that is naturally mined (and cleaned and cut) and one that is made in a laboratory? (the latter with the intent of making jewellery/resembling a natural diamond, of course) They are chemically identical, aren't they? 72.128.95.0 (talk) 19:47, 2 June 2011 (UTC)[reply]