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August 19

Psychology of pricing and beach nourishment projects

Hi, I have learned that managed retreat (moving away from the shore) is an unpopular idea amongst the public, in part because of its high short term costs (both beach nourishment and maintaining coastal armoring structures such as jetties are more expensive over a long term period (eg. decades)). I was wondering, are there any psychological studies that show that consumers tend to be more afraid of making purchases that have high short term costs, than making purchases that have low short term costs but higher long term costs? Many people get in trouble with credit cards because they allow people to make quick convenient short term purchases, but often lead to higher long term costs (in the form of interest rates or late payment fees). Thanks. — Preceding unsigned comment added by 99.146.124.35 (talk) 00:06, 19 August 2013 (UTC)

There has been a lot of research about that topic. Our articles on temporal discounting and intertemporal choice describe some of it, although they are written at a pretty technical level. Looie496 (talk) 00:58, 19 August 2013 (UTC)

The world is rife with the consequences of that kind of thinking. When you buy an inkjet printer for your computer - it's amazingly cheap - under $100 in some cases. Then you go to buy a few grams of ink and you're paying $50. Computer game consoles like the PS-3 and Xbox 360 are sold for prices well below the manufacturing cost - and the companies that make games are forced to enter into costly licensing for the privilage to write games for them - the cost of games is therefore much higher than it would otherwise be in order that the sticker shock for the console hardware is lessened. Cellphones worth $300 to $400 are sold for $100 with a two year contract to buy cell phone service at significantly more than the going rate.

In every case, people are suckered into these expensive long-term costs by the short-term value. SteveBaker (talk) 01:38, 19 August 2013 (UTC)

Phone companies in the UK are starting to be clearer in their phone plans. The O2 refresh scheme gives a super clear explanation of exactly what you pay for your phone on different contracts. For example for the iPhone 5 you actually save £120 (20% of the cost of the phone) by fiddling with the contract you want - and a handy link to find the lowest price. For example. 110.3.247.175 (talk) 12:57, 19 August 2013 (UTC)

I've been reading that cancer cells communicate with each other...

and also that slime mold cells communicate with each other. How do the signalling methods compare? Thanks.76.218.104.120 (talk) 05:32, 19 August 2013 (UTC)

Most living cells communicate, to a greater or lesser degree. The subject that coveres this topic is Intercellular communication and it is very complex. Vespine (talk) 06:57, 19 August 2013 (UTC)

Thanks,Vespine76.218.104.120 (talk) 22:55, 21 August 2013 (UTC)

Upside down Mirror Image

why do some mirrors show images upside down. — Preceding unsigned comment added by 197.220.100.142 (talk) 11:43, 19 August 2013 (UTC)

See curved mirror. הסרפד (call me Hasirpad) 12:39, 19 August 2013 (UTC)

Antibiotics - Safe Amount To Take

My queastion is, how many courses of antibiotics (or how much) is safe to take per year ?
One reason for asking is I was prescibed antibiotics for a chest infection when I was little, but because I still had it a week or two after the course was finished (Not sure but I think it was a 28 day course) my parents took my back to the GP. This happened 3 or four times until my parents happen to mention that I've already had antibiotics when the GP suggested for me to have some more antibiotics . When he checked my records (he later claimed there was some sort of problem with their computers) he said I'd have to have something else because I'd taking more than the recommended amount for that year.
another reason is, years earlier a similar thing happened with my sister. She had a ear infection, & she was given so many courses of antibiotics (later explained to us by doctors in the hospital) that she went partialy deaf. When she was rushed to the hospital, where they took her off the antibiotics & gave her something else to take instead & they told my parents that her hearing might come back. Luckily it did. Scotius (talk) 12:38, 19 August 2013 (UTC)

Wikipedia does not respond to requests for medical advice. Ask a medically-qualified person. AndyTheGrump (talk) 12:41, 19 August 2013 (UTC)

I'm sorry - but the Wikipedia Reference Desk is not allowed to dispense medical advice. Besides that, the answer would be very complicated because it'll depend on body weight, gender, which antibiotics are being prescribed, other drug interactions and so forth. This is really a matter for a doctor to answer for each individual patient. SteveBaker (talk) 12:49, 19 August 2013 (UTC)

I think it's safe to say that the medical community has a different opinion on the appropriate use of antibiotics today than even ten years ago. Today, where I live doctors never prescribe antibiotics to patients if there is no risk posed by the infection to the long term health of the patient. So, even if an antibiotic would help you to recover faster and be less ill, the doctor won't prescribe it to you. So, any use of antibiotics is judged to be potentially unsafe and can only be justified if it avoids a significant health risk to the patient. It's up to the doctor to make this assessment in individual cases. Count Iblis (talk) 13:09, 19 August 2013 (UTC)

I agree that we can't answer this, but I should point out that your question simply can't be answered, even by a physician. "Antibiotics" represent a vast range of substances, some of which are used only in dire emergencies with very specific and severe side effects (for example, ciprofloxacin can break tendons; many antibiotics cause ototoxicity or damage the liver or kidneys etc.). On the other hand, simple honey is a moderately effective antibiotic that has been used for many thousands of years, and pretty near harmless. Most... fall into some intermediate category. You just can't say "X courses per year" for a grab bag of miscellaneous antibiotics - but if you used just one all the time you'd have too much trouble with resistance for it to be useful. So there's just no answer to the question. Wnt (talk) 19:27, 19 August 2013 (UTC)

I agree that there's no fixed answer to the question. Doctors here in the UK do prescribe antibiotics, but they usually vary the type prescribed so as to reduce the danger of resistance building up. Different authorities at different times in different countries have recommended different "maximum amounts" for different antibiotics, but there is no fixed rule. The modern approach seems to be to avoid prescribing any antibiotic unless it is considered really necessary, but to prescribe it for long enough to completely clear the infection. Dbfirs 11:34, 20 August 2013 (UTC)

Probability to find a electron in a specific region

Reading article about electron and Schrodinger Equations, I have seen that a region with more probability to find a electron in a Hidrogen Atom, or any other in energy state 1s, in in the center of atom. As we understood that in center of atom we have a nucleus where protons and neutrons are expected to be in potential wells, how can electrons and nucleons be expected to be in atom´s center without interacting with each other ? I thank for some help. — Preceding unsigned comment added by Futurengineer (talk • contribs) 13:41, 19 August 2013 (UTC)

There is definitely an interaction between the electron and the proton. However any classical picture of the situation breaks down completely here. If you break down the 1s state by writing it as a sum over states where the electron has a definite position (this is what you effectively do if you write down the 1s wavefunction as a function of position), then this has to be interpreted as the electron being in a superposition of all these positions and interacting with the proton from all these different positions. The total energy of -13.6 eV of the system is a result from the sum of all the kinetic and potential energies at these different positions, including from the electron being inside the nucleus. Count Iblis (talk) 14:06, 19 August 2013 (UTC)

Yes, they may interact. Electron capture is just one of the more notable consequences of that interaction. Dauto (talk) 15:28, 19 August 2013 (UTC)

They definitely interact electromagnetically, otherwise the electron wouldn't be in a bound state (and atoms as we know them wouldn't exist). So maybe you ask whether they interact in other ways; and the only other known ways are by gravity (which is negligible in this case) and by the weak interaction. As Count Iblis said before me, the electron is in a superposition of all different positions, and only those very close to the nucleus allow weak interactions with a reasonably large amplitude. These interactions certainly lead to a small correction factor in a very accurate calculation of the binding energy and the wave function of the electron. It can be guessed that the correction is pretty small by estimating the probability of the electron being inside the proton in light hydrogen: The Bohr radius is about 60 thousand times as large as the proton radius, and in a crude approximation the probability is given by the ratio of proton volume and the volume of a sphere of the Bohr radius, which is about p = 5*10^-15, a very small number. Icek (talk) 13:13, 20 August 2013 (UTC)

The effect on the energy levels of the electron is negligible indeed. But the effect on the probability of electron capture is very important. The chance of an electron that is not in a s state being captured by the nucleus is very small because of the low probability of finding such electrons in there. Dauto (talk) 14:59, 20 August 2013 (UTC)

Suppressors of evolution?

Would it be correct to say that dinosaurs in fact suppressed or hindered the evolution and emergence of more diverse wildlife and smaller life forms that we see today? The modern fauna, that emerged within a relatively short time compared to several millions years of dinos' domination, seems to be more differentiated. Specifically, humans for example evolved within an extremely short period compared to dinos' era and many millions of years were dominated by essentially a single clade, inferior to humans and other modern animals. --93.174.25.12 (talk) 14:42, 19 August 2013 (UTC)

I've read that the reason why the dinoarus were themselves not so diversified as modern animals had to do with the flora of the time which was not as diverse as that as today. Flowering plants only evolved during the Jurassic, fruit bearing plants evolved much later. The plant eating dinos had only conifers and ferns on their menu. But then one can ask why it took so long for the flora to evolve fruit bearing plants, perhaps the biology experts here can answer this... Count Iblis (talk) 15:15, 19 August 2013 (UTC)

You'll probably find Punctuated equilibrium interesting. Dauto (talk) 15:21, 19 August 2013 (UTC)

When the [big] dinosaurs were all gone from the face of the earth (today, there are small dinosaurs; we call them birds), the earth allowed the adaptive radiation of different lifeforms, particularly small mammals that were being hunted during earlier eras, and that led the mammals to grow in size and diversify. Of course, I'm sure there were some diversification and evolution in early mammals during the dinosaur era too, but they generally could not grow larger in size, because they could be hunted by the dinosaurs as prey. So, I wouldn't say that the dinosaurs completely suppressed or hindered the evolution and emergence of diverse wildlife. Perhaps, the word guided would be a more suitable term, as the dinosaurs, early mammals, and feathered birds all interacted with each other in the ecosystem. Sneazy (talk) 15:42, 19 August 2013 (UTC)

That's all rather teleological and vastly over-simplified. Our article on the Cretaceous–Paleogene extinction event says "Mammalian species began diversifying approximately 30 million years prior to the K–Pg boundary. Diversification of mammals stalled across the boundary. Current research indicates that mammals did not explosively diversify across the K–Pg boundary, despite the environment niches made available by the extinction of dinosaurs." References are here and here. Gandalf61 (talk) 16:01, 19 August 2013 (UTC)

And, of course, "the dinosaurs" were themselves a large, diverse, and evolving group. So evolution was happily working away, creating bigger and smaller dinosaurs, bipedal and quadrupedal ones, possibly cold- and warm-blooded species, feathered, scaled, horned, and winged dinosaurs. No to mention mosasaurs, ichthyosaurs, plesiosaurs and pterosaurs, all sharing some part of the environment with dinos. --Stephan Schulz (talk) 16:03, 19 August 2013 (UTC)

To make some flagrant speculation, just thinking out loud (or perhaps asking a question of my own, if someone answers): I wonder what the effect of hibernation/estivation is on overall species diversity? As I understand it, the things that survived the meteor were generally things that could bunker in a hole in the ground and forget the world a while. (True, I would make a very big stretch in supposing that the ability of the Common Poorwill, shared on a nightly basis by some other species, might be ancestral) But I'm thinking that the net evolutionary effect of having so many species starting out with a ready resort to inactivity might increase the overall number of ecological niches as a whole. Wnt (talk) 20:19, 19 August 2013 (UTC)

Hibernation/estivation can easily make species undergo speciation and diversify by temporal isolation. Some species can be very "choosy" in the mating process and will only mate in a particular time of year or a particular time of day or during a particular time in an organism's life cycle. Sometimes, many evolutionary pressures are at work - geographical isolation, genetic drift (for a small and isolated population), gene flow (and migration), and natural selection. For instance, there may be a huge tsunami that goes inland and floods the lands until the valleys are temporarily filled. During the time when it is filled, flora and fauna adapt to the flood. Isolated related species of the flora and fauna may be trapped and diversify in their own way. And natural selection may act on the flora and fauna to cope with the new, flooded environment. Sneazy (talk) 22:38, 19 August 2013 (UTC)

That bit about evolution occurring rapidly after flooding due to a tsunami sounds speculative, but I assume that you would not have said it without a source - could you provide one? Sounds interesting. -- Scray (talk) 23:47, 19 August 2013 (UTC)

I confess that the specific example is fabricated based on my knowledge of evolutionary biology. My intention is to make a point that many evolutionary pressures can work on species simultaneously, creating a dynamic biosphere. I'm sorry if I sent an implication that the evolution is rapid or shortly after the flood; I wasn't really taking into account of time, and I did not mean to refer to the same species before or after the flood. Some may die off; some live; survivors adapt, if any. However, now that you have mentioned it, I actually have found a research article on my library's database that supports the instance of a tsunami during the K-T boundary and the stalling of adaptive radiation.

• Source: Hansen, T. A., Kelley, P. H., & Haasl, D. M. (2004). Paleoecological patterns in molluscan extinctions and recoveries: comparison of the Cretaceous–Paleogene and Eocene–Oligocene extinctions in North America. Palaeogeography, Palaeoclimatology, Palaeoecology, 214(3), 233-242. doi:10.1016/j.palaeo.2004.06.017

• Abstract: Exposures across the Cretaceous–Tertiary (K–T) and Eocene–Oligocene (E–O) boundaries, in Texas and Mississippi, respectively, probably represent the most complete and best-preserved fossil molluscan sequences across these boundary intervals in the world. Outcrops from both boundaries contain pristine aragonitic and calcitic molluscan shells, which were deposited in fine-grained sediments from open marine environments. The K–T and the E–O extinctions exhibit very different recovery patterns, probably reflecting very different causes as well as magnitudes of extinction.The K–T sequence contains a molluscan fossil record that is consistent with an abrupt extinction event at the K–T boundary and a prolonged initial recovery in hostile oceanographic conditions. The uppermost 10 m of Upper Cretaceous sediments contain a diverse (approximately 40 species) molluscan fauna dominated by suspension feeders. The earliest Paleocene sediments immediately above the tsunami bed contain an impoverished fauna dominated by deposit feeders. The Paleocene fauna slowly climbs in diversity but remains relatively impoverished and dominated by deposit feeders for several hundred thousand years after the extinction in conjunction with anomalous δ13C values that suggest prolonged suppression of marine primary productivity. Diverse suspension-feeder dominated molluscan assemblages reappear with the resumption of normal conditions of primary production. In the long term, early to middle Paleocene gamma diversity includes evolutionary “bloom taxa,” families that exhibit unusual speciation bursts that subside in the Eocene. Total diversity for the Gulf Coast does not approach Cretaceous levels until the Late Eocene representing a total recovery interval of nearly 25 million years.While the E–O event also reflects a molluscan extinction rate of over 90% in the Gulf of Mexico, there are no signs of hostile environmental conditions in the recovery fauna. Early Oligocene molluscan assemblages are diverse and dominated by suspension feeders characteristic of normal marine conditions. The hiatus at the E–O boundary, however, could have obscured a short-term recovery fauna. There is also no sign of long-term perturbation by the E–O extinction. There are no bloom taxa and gamma diversity approaches pre-extinction levels within a few million years. The overall pattern of the E–O extinction is consistent with extinction (and/or migration) associated with long-term cooling.

Sneazy (talk) 00:11, 20 August 2013 (UTC)

• The relevant concept to explore is niche (ecology). Dinosaurs and their kin "suppressed" evolution into niches like whales, bats, and megafauna, because they were already filling those niches well enough to make the intermediate niches like Ambulocetus's unrewarding. (Evolution excludes two species from having the same niche unless they have non-overlapping ranges: e.g., both rabbits like meadows, but only one can tolerate swampy lowlands and the other the cold heights. The presence of a good land and good water predator will exclude a mediocre amphibious predator.) The three major factors of the dinosaur era include the existence of dinosaurs already filling many niches, the lack of flowering plants until the end of the Mesozoic, and the unified Pangaean landmass preventing isolation at a continental level. It wasn't dinosaurs, for example, that prevented the evolution of primates, but the lack of suitable fruit and fruit-eating insect prey for the primates to consume. Once the continents broke up we got such groups as the Afrotheria and the Boreotheria as local experiments on the broken-up continents. As for hibernation, any process that lengthens an animal's lifespan in regard to age at first breeding will, ceteris paribus, slow down evolution--see the Sibley-Ahlquist taxonomy. But selection pressure may be higher on the slower-breeding animals, which can balance out the equation. μηδείς (talk) 01:08, 20 August 2013 (UTC)

how many percents of cpr cases are successful?

It intresesting for me to know how many percent of cpr cases are successful. Do you know something about? thank you 176.13.161.70 (talk) 15:41, 19 August 2013 (UTC)

Cardiopulmonary_resuscitation#Effectiveness 163.202.48.125 (talk) 15:56, 19 August 2013 (UTC)

An important fact to note in that article is the survival rate when not getting CPR. It's very low. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:52, 19 August 2013 (UTC)

I remember reading that traditional CPR is no more effective than using a toilet plunger on the victim's chest. Not that a plunger is very effective, it's just that CPR isn't any better. StuRat (talk) 14:29, 20 August 2013 (UTC)

Toilet plunger actually at least as effective (and led to development of new assistive devices.

• http://dfw.cbslocal.com/2011/01/24/toilet-plunger-rescue-leads-to-new-cpr-procedure
• http://www.popsci.com/technology/article/2011-04/device-modelled-after-toilet-plunger-improves-cpr-success

...it was trivially easy to find this by google so we can discuss actual news and science instead of random recollections thereof. DMacks (talk) 16:43, 20 August 2013 (UTC)

As the first answer to the OP indicates, getting CPR quickly significantly improves your chances of survival, compared with just letting him lie there and hoping for divine intervention. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:08, 21 August 2013 (UTC)

"Survival" and "success" aren't necessarily the same. You might be interested in this episode of Radiolab which explores the 2003 survey by Joseph J. Gallo on what heroic measures physicians would want for themselves. Gallo's survey of doctors says 90% of those interviewed would not want to receive CPR - not because it is necessarily ineffective, but because of the quality of life of someone saved by CPR. This story cites a study saying 8% of CPR patients survived for more than one month but that only 3% subsequently could lead a "normal life". You do occasionally hear of medical doctors who have "do not defib" or "no CPR" tattoo (e.g.) for this reason, posing an ethical and legal dilemma for responders. -- Finlay McWalterჷTalk 13:13, 22 August 2013 (UTC)

I should note that only 8% of CPR patients surviving isn't necessary an indication that CPR is ineffective. Rather it's as much an indication that first responders are apt to perform CPR whenever there seems to be the remotest chance of it working, fearful of being accused (by relatives and in court) of having given up too soon. One of those articles I linked above compares the effectiveness of CPR on TV dramas to the actual procedure, giving people an undue faith in its practical effectiveness. -- Finlay McWalterჷTalk 13:26, 22 August 2013 (UTC)

Alcubierre drive

In the main article about the alcubierre drive the part "physics" an "placment of matter" discribes the problem of tachionic motions.

my question now, is it necessary to arrange an infrastructur along the path of the warp bubble because the crew of the ship inside the bubble can not stop the bubble by itself? or ist it necessary cause the warp drive would not work without this infrastucl like a train without railways?

peter, germany — Preceding unsigned comment added by 89.204.155.187 (talk) 18:16, 19 August 2013 (UTC)

If you have the power to fold space there's no telling what you can do. Wnt (talk) 19:28, 19 August 2013 (UTC)

Well, you could create an inescapable prison. You could create a box that is bigger on the inside. You could scratch any part of your back without using a backscratcher. It is the ultimate way of hiding something, so that it is 'there', but not actually there. Oh, you can build computers that don't have any wiring (wireless electricity transmission, without converting energy into another form). Plasmic Physics (talk) 00:47, 20 August 2013 (UTC)

...And, you'll never again have to struggle with opening another jar of pickles - just fold the space around it to reach through the lid. Plasmic Physics (talk) 07:28, 20 August 2013 (UTC)

I'm not sure what you are asking, but here is a relevant article from a popular science magazine (New Scientist): [1]. I'm relatively sure that it is speaking about the Alcubierre drive. Plasmic Physics (talk) 02:34, 20 August 2013 (UTC)

There isn't any sensible physical theory in which you can talk about how the Alcubierre drive "works". General relativity lets you compute an energy distribution for any spacetime geometry, including one with a warp bubble in it. The energy distribution for the warp bubble geometry is incompatible with the rest of known physics. The only way it could ever work is if God created an as-yet-undiscovered substance with exactly the right properties because He wanted us to be able to make warp drives. There's no way to know how we'd control this miraculous substance.

That said, the outside of the warp bubble in Alcubierre's geometry is causally disconnected from the inside, so indeed the occupants would not be able to actively control it (without FTL signaling, which would defeat the purpose of talking about GR warp drives in the first place). -- BenRG (talk) 12:00, 20 August 2013 (UTC)

It's worth mentioning there is an article Alcubierre drive and also a potentially more interesting article White–Juday warp-field interferometer. I still don't get why, if the inside and outside of the bubble are causally disconnected, you would find it easier to open it from the outside than the inside. Wnt (talk) 14:01, 20 August 2013 (UTC)

They're not entirely causally disconnected, there are just parts of the outside (specifically the front) that aren't in the causal future of any inside point as long as the thing is moving. But the whole trip is contained in a future light cone whose apex is on the outside, so there are outside locations from which you could potentially affect everything.

As for this experiment, I haven't looked at it, but in general, the people working on warp drives don't appear to understand the physics very well. I imagine they get funded because the people who allocate the funds don't understand the physics either, and they get press/Wikipedia coverage because the reporters don't understand the physics. The paper describing this particular experiment was presented at a conference that's unlikely to have any experts on GR in the committee or the pool of reviewers, which makes me wonder why they accepted it. -- BenRG (talk) 16:33, 21 August 2013 (UTC)

August 20

Hypothermic/hypothermia surgery

I have found Google information about the use of deliberate hypothermia in brain and cardiac surgery. It is apparently being used in Ecuador for, for example, foot surgery, but I can't find any references to this technique. Anybody out there have better sources and or knowledge? Thanks Bielle (talk) 02:57, 20 August 2013 (UTC)

Cryotherapy would be a good place to start. 24.23.196.85 (talk) 04:20, 20 August 2013 (UTC)

Thank you, but cryosurgery is used only for very small parts of the body. The description I was given was of some sort of "ice machine" which "froze" the whole lower half of the body. This cannot be literally true, because of the response of cells to freezing. Any other suggestions? Bielle (talk) 16:15, 20 August 2013 (UTC)

Wikipedia Has An Article On Everything! - see Therapeutic hypothermia. Alansplodge (talk) 17:49, 20 August 2013 (UTC)

sun setting at different times

A couple of weeks ago while I was driving home (Central Ontario, Canada), I pulled over to take a picture of an amazing sunset. Later, I sent the pic to my friend in Ghana and noted that the pic was taken at about 8:30 pm. She was surprised as the sun set in Ghana at about 4:30 pm. When I look at a map I see that Ghana is much closer to the equator than Canada is. Does this explain why the sun set at different times in the two countries? 173.35.158.194 (talk) 03:25, 20 August 2013 (UTC)

The short answer is "yes". See Sunset for a better one. Bielle (talk) 03:33, 20 August 2013 (UTC)

Are you sure that she said sunset was at 4:30 p.m. in Ghana? Does she live behind a big hill? Ghana is not on a time zone significantly ahead of its local time. Dbfirs 11:24, 20 August 2013 (UTC)

Sunrise and sunset in Ghana is never far away from six o'clock, it is quite close to the equator and in an appropriate timezone. I was wondering if they were referring to what the time was in Ghana when there was a sunset in Ottawa, it is four hours out currently but unfortunately the wrong way for this so I haven't the foggiest what's happening. Dmcq (talk) 11:40, 20 August 2013 (UTC)

Time zones and daylight savings time could also shift sunset times by up to 2 hours in Ghana relative to Canada. There could also be differences in how "sunset" is defined. It could be when the first part of the Sun goes below the horizon, or the last bit, or when the sky goes black. StuRat (talk) 14:33, 20 August 2013 (UTC)

There is no way the sun sets in Ghana at 4:30 PM. Dauto (talk) 14:53, 20 August 2013 (UTC)

Day length explains how surise and sunset vary by latitude and where the earth is in its annual orbit around the sun. Ecliptic explains the cause behind it. Hope this helps.Diwakark86 (talk) 18:50, 20 August 2013 (UTC)

Ghana runs on GMT all year, and no region is very far from the meridian (between four degrees west and two degrees east), so if the friend in Ghana really did mean 4:30 local time then the only explanation is that she lives just east of a hill, and perhaps just east of a tall forest. Local terrain can significantly affect the time at which the sun apparently sets, though daylight will remain for much longer. Dbfirs 20:31, 20 August 2013 (UTC)

Tomorrow, the sun will set at 6:12 pm local time [2] in Accra, Ghana. That's not 8:30 pm, but it's a far cry from 4:30. --74.43.43.6 (talk) 03:03, 21 August 2013 (UTC)

Thanks everyone. I suspect that it is a combination of definition and language. 173.35.158.194 (talk) 02:27, 22 August 2013 (UTC)

There are various websites that allow computation of times of sunrise and sunset, simply by nominating latitude, longitude and timezone. I have successfully used the following site to compute a table of sunrise and sunset in Ghana for the whole of 2013: Sunrise, Sunset and Twilight Times. Dolphin (t) 23:29, 22 August 2013 (UTC)

Anchors unzipping

I've recently watched The Eiger Sanction with a friend of the family, and he told me that he found the final scene implausible: he said that when anchors unzip from the top because of excessive strain, they all go, so it would be impossible for Clint to remain hanging from his rope while the other three fall to their death. However, I have my doubts about this -- if the bottommost anchor was driven in much more firmly than the others, I don't see why it can't remain in place. Neither of us is a professional mountaineer, so I'd like some educated commentary on the subject. Thanks in advance! 24.23.196.85 (talk) 04:34, 20 August 2013 (UTC)

The Eiger article has an unsourced comment saying that the film crew included experienced climbers to ensure the accuracy of the climbing scene. The novel was written before the invention of spring loaded camming device so I'm not sure, but I would say that with modern equipment having 3 anchors fail and the fourth hold would be possible - after all, even if they fail the other anchors should slow down the fall - but I don't recall even seeing such a thing happen (I've seen one or two anchor failures happen though, with modern equipment trad climbing). Not having seen the movie, I have a hard time imagining how that situation would let one member survive but not the others; also note that even if the fourth anchor holds, the distance fallen essentially doubles with every missed anchor, and if there is any angular momentum the climber would likely kill themselves by crashing into the cliff. Effovex (talk) 15:12, 20 August 2013 (UTC)

A well placed cam can stop a fall of well over 10 kN. I would guess a well placed pitons would be able to hold at least as much and probably more, as the problem with pitons isn't their strength but the damage they cause to the surface (see Clean climbing). If you can provide a description of the distance between the pitons and the weight of the climbers, I'm sure someone could calculate the maximum amount of force that would be exercised on the remaining anchor. Are they climbing strictly vertically? Effovex (talk) 15:23, 20 August 2013 (UTC)

This climbing forum gives a generally favourable review to the film; there are a few quibbles but nobody mentions the failing pegs. John Cleare is mentioned as an advisor. Our Eiger article also states (with a reference) that Dougal Haston, and Hamish MacInnes were involved. Alansplodge (talk) 17:42, 20 August 2013 (UTC)

Thanks! So I guess this situation would be possible but unlikely? 24.23.196.85 (talk) 06:29, 23 August 2013 (UTC)

Human body maximum performance

I read an article which claimed that the human body overall performs at its best between ages 25 and 28. Is this true? Does it differ between people, gender race etc? Clover345 (talk) 10:21, 20 August 2013 (UTC)

What kind of performance are you talking about? 163.202.48.126 (talk) 11:26, 20 August 2013 (UTC)

Aging and athletic performance. The physical peak for "most sports" is 25 to 35. This is likely to be lower for women - I doubt you'll find anything concrete for the different races. Some sports however do require more training than others and you might find that older players tend to do better than younger ones (e.g. golf). Also [3]. If you're talking about academic performance or something else then the answer will be different. 163.202.48.125 (talk) 12:11, 21 August 2013 (UTC)

examples of organs which made of some kinds of tissues

Could you give me some examples for organs which made of some kinds of tissues And some examples for tissue which made of some kinds of cells? Thank you a lot!176.13.161.70 (talk) 16:55, 20 August 2013 (UTC)

You may wish to read our articles on organ (anatomy), tissue (biology), and cell (biology) to help you do your homework. DMacks (talk) 17:01, 20 August 2013 (UTC)

By the very definition of tissue, all organs are "made of some kinds of tissues". So just pick an organ, and find out how it is constituted. Plasmic Physics (talk) 00:17, 21 August 2013 (UTC)

doing a blood test for who did mastectomy

Today I was in the clinic for blood tests, and I saw that the nurses said to a woman who made mastectomy in one side, that she is allowed to make a blood test only in the another side, because she don't has limph nodes in the side of mastectomy. I also was in the room when it happened but I ashamed to ask about... even it's intresting me. So, here I feel good to ask about:) My questions are: 1. What is the problem or danger to make a blood test in the side of the mastectomy (this is the side where there is not limph nodes). 2. What have to do when a woman made mastectomy in her two sides breasts, can she not be taken a blood test at all, or is there any solution for her? (p.s. It's not medical advice, because I'm a man and just intersting to know the issue. So, please don't note about). thank you. 95.35.232.184 (talk) 17:46, 20 August 2013 (UTC)

Wikipedia:Reference desk/Archives/Science/2013 August 12#Lymph node removal and blood pressure measurement got no responses, but that question does include an answer to the question #1 here. DMacks (talk) 17:56, 20 August 2013 (UTC)

Googling finds lots of hospital (or similar) patient-advice webpages talking about it. They mention a problem with the cuff causing lymphedema (consistent with my previous link). And note pros and cons of the obvious alternative of measuring blood pressure "somewhere else" or "by means other than compression cuff". DMacks (talk) 18:07, 20 August 2013 (UTC)

It is a matter of balancing risk. For a woman with a recent mastectomy, the risk of penetrating the skin on the arm on the mastectomy side, as is required to get a blood sample, is that infections will be more complicated, as part of the role of lymph nodes is to prevent the spread of infection. Infection toxins may build up in the arm due to the poor lymph drainage. For the same reason, women with mastectomies involving the removal of lymph nodes are advised to give up gardening or any activity that has a risk of scratches (or at least wear arm length gloves). After a few years the lymph channels adapt and new lymph nodes grow, reducing the risk. For a woman who has had a mastectomy and lymph nodes removed on both sides, normally the mastectomies will be some years apart. Use the oldest surgery side for blood pressure taking, blood taking, and injections, as this lowers the risk. Note that for mastectomies, whether no lymph nodes are removed, some lymph nodes are removed, or all lymph nodes are removed, depends on the facts of the case, and the judgement and experience of the surgeon. If the cancer is discovered by feel or mammogram and is considered early, only the sentinel lymph nodes in the chest might be removed, and there is no more risk to the arm than for any other woman. Many women who have had breast cancer will have had chemotherapy via a drip in the other side arm. In some cases this will have "burnt out" the surface veins in that arm, making getting a blood sample difficult. The woman should insist that an experienced phlebotomist does it, and not just some ordinary general duties nurse. However, if only a general nurse is available, it's only a matter of risk, nothing to get too uptight about. A blood sample for lab testing can be taken from any surface vein on a limb. If the woman has no lymph nodes in both armpits from a double mastectomy (which is very unusual) blood can be taken from a leg or foot vein. However, as gravity will markedly increase the risk of uncontrolled bleeding, this should only be done in a hospital (or other situation where medical staff can get it under control) under the supervison of a doctor, and the woman will have to remain there until it is certain she won't bleed. — Preceding unsigned comment added by 1.122.245.38 (talk) 00:20, 21 August 2013 (UTC)

Raid Fly Spray

I seem to have an infestation of some kind with Blue bottles and got home from work today with my dining room full of them. So I grabbed a can of Raid fly killer (it may be this product but in the UK it's a blue can marketed as a fly and wasp killer) and sprayed at them directly wherever they were, including walls and windows, shut the doors and returned 15 mins later.

Then I read the directions on the can and part of the warnings state 'keep spray at least 1 metre from all surfaces and walls'. I certainly sprayed a good few surfaces as that's where the flies were sitting. I'm just wondering why, as it's an aerosol, it specifically states not to spray a wall even though spraying it the air leaves the insecticide on all sorts of surfaces.

Is it simply in case the spray rebounds off the surface you're aiming at? I'd think it's still better to aim at the problem rather than spray an antire room in the air and have the spray land on every surface

Thanks in advance --46.208.198.216 (talk) 21:59, 20 August 2013 (UTC)

If you have large numbers of them in your dining room, you'd better find the source... otherwise you can play with that can all you want and get nowhere. It's hard to comment on any potential toxicity without seeing ingredients for sure (not just 'something like it'), and even then it would be disallowed here as medical advice, but my pure guess is that if you can spray it in a room safely at >1m they must be more worried about the solvent than the chemical, i.e. for purposes of dissolving plastic, discoloring surfaces etc. Wnt (talk) 22:05, 20 August 2013 (UTC)

That makes sense thanks, I assumed it was potential toxins left in the home. I appreciate your advice that I should find the source, but this has happened a few times over maybe the past 8 years, this is the second time with flies and also I had a problem one year with bees (I work away from home and got back one weekend with dozens of tiny bees dead in front of the window). I've had pest control companies out and they were at a loss unfortunately --46.208.198.216 (talk) 22:28, 20 August 2013 (UTC)

August 21

Carbon Footprint Q: Whose foot is that, then?

In Sydney, Dick Smith, environmentalist, businessman and aviator, recently hosted a very interesting TV doco on renewable energy. In it, he noted that Australia has one of the largest carbon footprints(per capita)in the world, mainly in consequence of the massive amounts of coal we mine and export.

But that made me think: which party incurs the responsibility for the carbon release: the exporter, or the importer, which in our case is China. If it is the exporter – us – then China is virtually blameless for any carbon debt, as all the nations that sell them coal, iron and the rest are the ones who are fitted up as the guilty parties. But I have read that they too have a very big carbon footprint. Is there some rather shonky bookkeeping going on here, where carbon emissions are being counted twice? Myles325a (talk) 06:22, 21 August 2013 (UTC)

Environmentalists generally prefer alarmism so they would prefer doing the calcs to make the numbers appear worse for everyone. That being said, you could also argue - since the Chinese use the coal they buy from Australia to generate power to manufacture goods which they export to other countries - that those countries should bear the carbon footprint. So the US, which consumes much of the stuff manufactured in China, should have the CO2 from the coal mined in Oz in their footprint. Otherwise see Carbon footprint. In reality the system is quite perverse with everyone pointing to other people's CO2 emmissions to justify themselves not doing enough to cut down their own emmissions. 163.202.48.125 (talk) 08:40, 21 August 2013 (UTC)

That's a bit glib. Acquiring resources, using resources, and obtaining the results are all different activities. You could count the mining operations footprint against Australia, the production using those resources against China, and the shipping of their output against the US.Phoenixia1177 (talk) 10:39, 21 August 2013 (UTC)

The question makes it clear that’s not the case, though. The carbon released from the coal mined in Australia is contributing to Australia’s carbon footprint. Or at least that’s how I interpret the question. 163.202.48.125 (talk) 11:37, 21 August 2013 (UTC)

No, the question expresses confusion about how the accounting is done, and some guesses that things might not be accounted for in the way that we might expect. There are indeed many ways such things can be calculated, but it is wrong to assume that emissions made in CN by burning coal mined in AU are counted as AU emission, merely because the OP is unsure of what's going on. SemanticMantis (talk) 15:27, 21 August 2013 (UTC)

Myles, can you give us a link to any specific reports? We can't really say how the carbon accounting was done unless we can see the original documents (And I can't find/watch the show right now). I will say that coal mining is a major source of emissions, even not counting any emissions from the burning of coal. Consider: all the gasoline to power trucks, electricity for lights, not to mention heavy digging equipment, manufacture of specific tools, etc. All that goes into the life cycle analysis of mining coal, and much of that energy is derived from fossil fuels. So it could be that Smith was basically correct that mining coal is a big part of AU's carbon footprint, even if the burning of said coal in CN is not. SemanticMantis (talk) 15:27, 21 August 2013 (UTC)

Many parties are involved. See "Environmental impact of the coal industry" and "Environmental impact of shipping" and, more generally, Category:Environmental impact by source. Sellers are enticed by high profits, and buyers are enticed by low prices, and often the natural environment (our natural life support system) pays a price. See "Environmental full cost accounting" and "Ecological debt". The natural environment can be affected negatively by resource extraction and processing; commodity distribution, use, and misuse; and waste disposal. A responsible person can do a limited amount of good without community support, but we can all do much more if everyone takes individual responsibility.

—Wavelength (talk) 16:33, 21 August 2013 (UTC)

The point here is "does it matter?" - this is a global problem. If Australia didn't mine the coal, China couldn't burn it. If China didn't burn coal, Australia wouldn't mine it. Who cares which of the two countries is responsible? Either one of them could choose to end it - so in any useful sense, they are both equally at fault. The naive statistic of "National Carbon Footprint" glosses over so many details in a dynamic, interconnected world as to be almost useless. Any simplistic view of the situation has to be viewed as a very general indication of a problem - and the specifics have to be examined before deciding on some course of action. If the world decided that this trade between Australia and China was unacceptable, political pressure would likely be exerted at both ends of the supply chain.

If China was pressured into not buying the coal - probably the Australian mining industry would sell it somewhere else. The sudden glut of coal would result in a dramatically falling price of the stuff on the open market - which would likely result in more Australian power generators burning it instead - and other countries would probably step in to buy Australian coal at this lower price point.

If Australia was pressured into not mining the stuff - the Chinese would buy it from some other country - a shortage of coal on the open market would push up the prices and encourage other countries to step up their production rate accordingly.

No single "fix" for this problem will work. It requires a global perspective. You need ALL coal mines around the world to reduce production and ALL coal fired power plants in every country to reduce their consumption. That kind of global cooperation has proven elusive...which is a very depressing situation.

SteveBaker (talk) 14:10, 22 August 2013 (UTC)

OP myles325a back live. It matters to me Steve coz while I am an environmentalist I despise the Green’s natural position that they can lie thru their teeth whenever they feel the end is worth it, while becoming holier than thou whenever they spot a fib that doesn’t suit their purposes. Activist literature is full of colossal exaggerations and outright falsehoods, and in the end it does their causes much harm, as the public founds out eventually and becomes cynical.

I don’t like propaganda, and I don’t like crappy statistics. I like to know the truth, and if some fanatic is counting carbon footprints twice, then I wanna know about it, and I want the lie exposed. Call me an old fuddy duddy but I’ve had an absolute gut full of the mealy mouthed post modernist view that “there is no such thing as truth”, and it’s all just a matter of what suits you, sir. Myles325a (talk) 05:27, 23 August 2013 (UTC)

Transmission of light through transparent medium

Okay, so in a transparent medium with a refractive index greater than 1, light is propogated with a velocity that is less than c. I understand the wave explanation of this in terms of electromagnetic radiation, distinction between group velcoity and phase velocity etc. But what actually happens at the level of individual photons ? Does each individual photon travel at a speed less than c ? Or do individual photons travel at c but the slowing down is a bulk effect because photons are absorbed and re-emitted by electrons ? Or is the slowing down the result of some complicated interaction involving virtual photons ? I've read the articles on refractive index, speed of light, slow light and transparency and translucency, but they don't seem to answer this question. Gandalf61 (talk) 08:54, 21 August 2013 (UTC)

The Photon article under Photons in Matter goes into it. It mentions scattering and interaction with quasi particles.Phoenixia1177 (talk) 10:53, 21 August 2013 (UTC)

Thank you. Yes, photon says the slowing down is due to "blending of the photon with quantum excitation of the matter (quasi-particles such as phonons and excitons) to form a polariton; this polariton has a nonzero effective mass". So in short, it's quantum weirdness. Gandalf61 (talk) 13:31, 21 August 2013 (UTC)

Or just consider that the photon is itself an excited state of the electromagnetic field, the field in the medium is, of course, described by the free field plus the interactions with the medium and quantizing that will lead to a different beast than quantizing the free electromagnetic field. You can then intepret what you get in terms of free photons that mix with quasi-particles, but then given any Hamiltonian, you can always write that as a sum of two different Hamiltonians, so these intuive pictures are not always unambiguous. Count Iblis (talk) 14:22, 21 August 2013 (UTC)

The wave picture is just as correct as the particle picture. They are different ways of calculating the same thing, mathematically. The particle picture works classically too—loop-free Feynman diagrams give you classical electromagnetism, and the diagrams with loops are quantum "corrections". The phenomenon you're describing is classical, and the quantum explanation isn't fundamentally any different however it's phrased. -- BenRG (talk) 16:06, 21 August 2013 (UTC)

Yes, I understand that the wave model and the particle model are equivalent in the classical limit, when there are a large number of photons. However, the intensity of the incoming light can, in principle, be reduced until only a single photon at a time is transmitted. So the particle model must explain the behaviour of individual photons in a way that replicates the wave model in the limit of large numbers of photons. And any description of the behaviour of individual photons must be a quantum physics model, not a classical model. So I was looking for a description of the mechanism by which an individual photon is refracted and slowed down (or, indeed, speeded up if refractive index is less than 1) as it passes through a transparent medium. Gandalf61 (talk) 09:00, 22 August 2013 (UTC)

What you have to understand is that a photon in vacuum and a photon in a medium are not the same object. In a medium, the normal modes of oscillation which will be quantized in order to obtain photons are not the same as the normal modes of a free field in vacuum. That fundamentally changes the Dispersion relation of the wave function. We chose to call it a photon just the same, but that choice really is arbitrary since the two objects have fundamentally different natures and properties. Dauto (talk) 13:21, 22 August 2013 (UTC)

I imagine that a lot of people have wondered at this, having been told that we can only observe light travel at the same speed c, we are then told that it can “slow down” when travelling thru a medium. How is that possible? I think the simple answer is that when light is travelling, it cannot be seen to move at any other speed than c, regardless of whether it is moving through empty space or honey. When a photon moves thru material, it can be briefly trapped by an electron in an atom’s shells. That excites the atom as it absorbs the photon, and then the atom sheds the photon (or another exactly the same) and returns to its previous state of energy. This procedure takes some little time. The photon ALWAYS travels at the same speed, but if we count these times when it is being absorbed and re-emitted, then it appears to travel at a lower speed than c. Myles325a (talk) 07:49, 23 August 2013 (UTC)

Is there any organ that made of only one tissue?

Is there any organ that made of only ONE tissue? (I have not found information about on Wiki) 46.210.138.154 (talk) 17:48, 21 August 2013 (UTC)

Well, to get an absolutely solid answer you'd have to first explain what you mean by a "tissue", but using the common meaning I'd say no, because every organ contains blood vessels, which are a distinct type of tissue. Looie496 (talk) 18:37, 21 August 2013 (UTC)

what do you think about the nail or hair, are they not organs or do they contain blood vessels? 46.210.138.154 (talk) 18:46, 21 August 2013 (UTC)

I've never seen nails or hair referred to as organs. (I regard these kinds of things as totally unimportant -- I'm just giving my impression of how most people say things.) Looie496 (talk) 18:50, 21 August 2013 (UTC)

Would the heart not count as this, being entirely composed of cardiac muscle? --TammyMoet (talk) 21:26, 21 August 2013 (UTC)

Epicardium, cardiac muscle, fibrous pericardium, serous pericardium, .... Reaper Eternal (talk) 21:33, 21 August 2013 (UTC)

Liver? Count Iblis (talk) 23:26, 21 August 2013 (UTC)

Blood vessels, also bile ducts (arguably there's a common origin to that cell type, but they look really different under a scope, and heck, there's a common origin to every cell type...) Wnt (talk) 06:17, 22 August 2013 (UTC)

Hmmm, I suppose the lens of the eye is one tissue type ... but it's not really an organ. Wnt (talk) 06:21, 22 August 2013 (UTC)

"the lens of the eye is one tissue type".^{[citation needed]} Have a look (ha!) at Lens (anatomy)#Lens structure and function. DMacks (talk) 14:38, 22 August 2013 (UTC)

I'd argue that the lens fibers and lens epithelium are the "same tissue type" at different stages of differentiation. I mean, if we hold the same standard to the liver, then we say there are three different tissue types because there are zone I, zone II, zone III hepatocytes. But even that is probably an incomplete description of the levels of differentiation involved... ultimately every cell is unique, and to some extent or other all the differences matter. Wnt (talk) 20:18, 22 August 2013 (UTC)

Absorbtion of non-soluble medicine.

Can non-soluble medicine pills be absorbed into the body through the mouth? This applies to the whole world. Pubserv (talk) 17:59, 21 August 2013 (UTC)

Not unless they are broken down by saliva. Otherwise the pill would just sit there forever. Looie496 (talk) 18:41, 21 August 2013 (UTC)

I mean pills that turn into powder when you crush them. Pubserv (talk) 19:58, 21 August 2013 (UTC)

I'm not an expert in medicine, but there are medications that don't dissolve in water, but dissolve with fats. Vitamin D, while not really a medicine, is one of the cases. --Wirbelwind(ヴィルヴェルヴィント) 00:23, 22 August 2013 (UTC)

Also, solubility isn't a 100% yes or no thing. A material might not be very soluble in water, but several hours churning in the digestive system, with water, fats, and acid thrown into the mix, might tend to break it down rather effectively. For example, calcium carbonate, present in many antacid tablets, isn't very soluble in water, but will react with the acid in the stomach and dissolve that way. StuRat (talk) 08:19, 22 August 2013 (UTC)

nervus cells called neurons?

why all cells of the body are called "cyties" (in example: osteocyties is of bone tissue, miocyties is of muscle tissue) while the nerves cells called neurons without 'cyties'? and second, how are called the cells of connective tissue? (see about the names of the cells of the other tissues in the first qustion). thank you. 46.210.138.154 (talk) 18:40, 21 August 2013 (UTC)

The term is "cytes", not "cyties" (no "i"). It's simply a synonym for "cell". As to why neurons are not called "neurocytes", the answer is simply tradition. Looie496 (talk) 18:45, 21 August 2013 (UTC)

thank you for the answer on the first qustion. what about the second question on the name of the cells of the connective tissue? Is it called conneccytes? :) 46.210.138.154 (talk) 18:54, 21 August 2013 (UTC)

Fibrocytes and fibroblasts. Icek (talk) 19:35, 21 August 2013 (UTC)

Sorry, fibrocyte is just not the general name of the cells which incloud all the connective tissues. A fibrocyte is only ONE of kinds of the the cells which build the connective tissue. There are some kinds of cells of connective tissues like adipocyte, chondrocyte, endothelium, and so on. So, you can not say that the name of all cells of connective tissue called "fibrocytes" like you can say that the miocyte is general name of all kinds of muccels tissues cells. It's intresting for me to know if there is a general term for connective tissue cells. 176.13.166.201 (talk) 20:51, 21 August 2013 (UTC)

August 22

if Mars still have more greenhouse effect like Earth

Before I didn't think planetary atmosphere and compositions are important in determining habitable zone but my college professor told me planetary atmosphere and composition are important to determine where the habitable zone will be, so if Mars have more greenhouse effect and atmosphere pressure roughly same that of Earth will it be much warmer than it is now? If it will be warmer than what will the average planetary temperature be? 23 F? If Titan didn't have any greenhouse effect will Titan be even colder?--69.233.252.198 (talk) 02:14, 22 August 2013 (UTC)

To determine the final temperature you'd have to know exactly how much greenhouse effect there will be. Venus is an example of a runaway greenhouse effect. The gas giants also have a pronounced greenhouse effect, although there they may be heated more by internal sources (radioactive materials, tidal forces, etc.). StuRat (talk) 09:12, 22 August 2013 (UTC)

The OP's question about Mars reminds me of what Carl Sagan had to say about the possibility of terraforming Mars and Venus. For Mars, you have to create greenhouse effects somehow. For Venus, it's the opposite - you have to introduce something that will somehow consume greenhouse gases. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:20, 23 August 2013 (UTC)

The immediately obvious solution would be to funnel enough of the gas from Venus to Mars.... 86.141.186.4 (talk) 12:53, 23 August 2013 (UTC)

Sure, a flexible, stretchable conduit of some kind, hundreds of millions of miles long. That shouldn't be too difficult to engineer. Kind of like a gigantic siphoning hose. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:34, 23 August 2013 (UTC)

Wormhole X-Treme! --Stephan Schulz (talk) 14:39, 23 August 2013 (UTC)

Do how old scientific articles matter the accuracy of informations?

Thistold me the article I linked were published in 1993 [4] and 1997 (Once and Future of the Sun) and is not a recent document. Do how old the scientific paper is published matters how accurate the information gets. Then why didn't the previous editors repost what their works in 1993 when the newer informations came up? I didn't thought the published dates matters that much. Or these authors are not require to repost information when new informations come up. Do these authors change their mind when the newer evidence comes up? I thought if they have changed their mind they suppose to repost their works they done in their earlier studies.--69.233.252.198 (talk) 02:38, 22 August 2013 (UTC)

Yes how the information is published does matter to how accurate the information is or at least how much you can trust it. If it's published in a refereed journal it means that someone else, who also works in the same field, has read it and not found errors within it. While if it's just put up on the web without being refereed it may well be correct but the information hasn't been independently scrutinised. As for the age of a paper, for a start computers are a lot more powerful now so you can enter more information. So with the same data you can get more accurate answers. Also the structure of the Standard Model of the Sun has changed quite a bit since 1992 with the lunch of SOHO. For new information a new paper would be written, submitted, reviewed and published. The old paper would be untouched after publication (there is only one publication run).Dja1979 (talk) 03:08, 22 August 2013 (UTC)

This is a largely subjective matter. It depends on the field of science or mathematics you're talking about. For example, Lord Kelvin's paper entitled "On the Age of the Sun's Heat engages in discussion on whether something made of coal could possibly be producing that much heat! Yet papers written by the exact same guy about the laws of thermodynamics in the exact same year remain as entirely valid and useful references, even today. Some fields just move faster than others!

As Dja1979 points out - recent spacecraft missions are still revolutionizing our knowledge of the sun - and papers from just a decade ago are unlikely to be of much use. Scientists working in a particular field tend to have a good knowledge of how far back they can reasonably refer without picking up on outdated information.

SteveBaker (talk) 13:53, 22 August 2013 (UTC)

It depends on the study done and the assumptions made. Sometimes a paper from a century ago can be a true pleasure to read, and as relevant today as the day it was written. There are even rare cases in which an ancient publication is found which was more knowledgeable than modern sources on a point (see Ge Hong regarding artemisinin) Wnt (talk) 14:38, 22 August 2013 (UTC)

Absolutely. It's not so much a matter of age, but a matter of what, if anything, has changed the scientific community's understanding since then. Math is not a science (in my view), but the results of math papers from e.g. 1900s are just as true now as they were then. Even in science, many old papers can be valid and useful for decades. If the OP is interested in specific examples in a given field, we could try to provide suitable refs. Of course, many old papers are outdated, because their findings have either overturned or improved (especially in younger subfields of e.g. computer science or genetics). This is generally held to be a good thing: it is how our understanding progresses, and is built in to the prevailing philosophy of science, specifically, Karl Popper's principle of falsifiability. (My WP:OR is that most currently practicing scientists are implicitly proponents of the Popperian view, even if they don't know it by that name, or don't think about philosophy of science much.) SemanticMantis (talk) 16:32, 22 August 2013 (UTC)

How do I identify a new type of earthworm?

having been around for many years, raised on a farm, dug worms for fishing, and gardened forever, I have discovered a completely different kind of worm this past week. I live in northern Ohio and came accross an area which has a very strong and firm eartworm population of 3 to 4 inch red colored worms that go crazy when uncovered. They twist and turn rapidly, they are very hard to hold on to, and they move very fast. Their bodies are very firm almost like a snake and they flop all over the place. Diameter is large. They are really strong and not at all like the thousands of giant earthworms that I have encountered before. They can extend themselves like a regular earthworm but their ends are very pointed. Can someone tell me if this is an unusual worm and what it might be? — Preceding unsigned comment added by 184.59.176.230 (talk) 17:22, 22 August 2013 (UTC)

Any photos you can offer? I can't help you either way, but someone else might be able to if you have one. Mingmingla (talk) 18:15, 22 August 2013 (UTC)

Just a guess, maybe a red wiggler? As their name suggests, they are feisty, and if I recall correctly, they are rather firm. They prefer compost to ordinary dirt. Was anything else different about this patch of dirt? Also check for the characteristic putrid smell that red wigglers release when agitated. SemanticMantis (talk) 19:18, 22 August 2013 (UTC)

Getting a tattoo while tanned or burnt

My friend is plannning on getting a tattoo after a holiday in Spain. He likes to ta his skin and thinks getting a tattoo the week after will pose no problems. My logic is that this is a bad idea and could probably scar him if he gets sunburnt. Not to mention the chance of blistering and a longer healing time. Does anyone know anything on this matter? Thanks ツ Jenova20 ^(email) 18:16, 22 August 2013 (UTC)

Some would argue that this is a borderline medical advice request. I don't know anything about tattoos, and Googling produces conflicting advice from various sources. Bearing in mind the medical disclaimer we usually wheel out in such cases, I would suggest you persuade your friend to consult the tattoo artist he is intending to use, in advance of his holiday. A reputable professional will be happy to advise him. - Karenjc 22:57, 22 August 2013 (UTC)

Borderline maybe but it's a hypothetical. I was always told when i got sunburnt that you shouldn't scratch it. Someone getting a tattoo over sunburn and making the area bleed seems like it would at the least scar or cause issues with healing. I'm not looking for medical advice, i'm asking a hypothetical question and interested if anyone knows. Thanks ツ Jenova20 ^(email) 08:10, 23 August 2013 (UTC)

Your friend is thinking of getting a tattoo and you're asking if it's likely to cause a scar if his skin is sunburnt - in what sense is that a hypothetical question? Richerman (talk) 08:37, 23 August 2013 (UTC)

I suppose i didn't word that well. I'm not asking if he should get it done, i'm just asking if there are any issues or studies on sunburn and scarring, healing, etc, when the skin is scratched or damaged further while healing. I think there would be but the Sunburn article doesn't really mention skin damage other than cancer. It's hypothetical in the sense that i've made assumptions for a made up scenario. If we can't do that then every health question here should be tagged in this way as medical advice. In that way most health questions and topics on cancer or common ailments should be banned from here as medical advice. See the point I am making? Thanks ツ Jenova20 ^(email) 08:59, 23 August 2013 (UTC)

But you didn't ask about sunburn and skin damage in a general sense, you gave what sounded like a question about a very specific situation. You even include a time frame and a vacation place.Phoenixia1177 (talk) 09:56, 23 August 2013 (UTC)

Indeed. A hypothetical question would be "if someone with a recent suntan got a tattoo, could this cause any problems ?". Jenova20 (talk · contribs) gave too many specific details for their question to be treated as hypothetical. This question definitley looks like a request for Medical advice, and Karenjc (talk · contribs) has given the only response that we can in that situation. Gandalf61 (talk) 10:11, 23 August 2013 (UTC)

Never mind. Not that important ツ Jenova20 ^(email) 10:18, 23 August 2013 (UTC)

I have a Toad in my house but I can't find him!!!

It was one of these guys!

Okay, so I'd just finished mowing the backyard, when I saw an Eastern American toad on my porch. Now, a lot of cold blooded things like to come up on my porch to get sun, lizards, toads, frogs, and insect you can imagine...so I usually just say hi and ignore them. Except...THIS ONE HOPPED IN THE HOUSE!!! I tried to catch it and put it back out but he got into the office. I searched everything, my boxes of cables, the papers on my desk, my cat's stomach, basically turned the whole place upside down...but I can't find him!!! I just know the poor little fellow will die of starvation or dehydration if I don't find him soon, is there anything I can do to lure him out? --Free Wales Now! what did I screw up?  18:38, 22 August 2013 (UTC)

Maybe make a toad home (google images here [5]), put in a moist sponge and hope it attracts the toad? I'd place one near where he was last seen, and another in the basement, if you have one. BTW, many toads, especially large ones, don't need much water on a daily basis, and only return to water to breed. So dehydration is not a big risk in the next few days, especially if you have a basement, which would also probably have toad food... SemanticMantis (talk) 19:13, 22 August 2013 (UTC)

It should be easier to hear and see him at night, since they're nocturnal. Might even try the same door it came in through. Like Mantis says, there's likely no immediate danger. Toads are generally much less susceptible to drying out than frogs, and cold-blooded animals don't starve so quickly. Cats generally hate the taste of toads, so I wouldn't look too hard into stomachs. A bit of damp grass may be tempting, if it's still there by tonight. InedibleHulk (talk) 19:34, August 22, 2013 (UTC)

They're pretty good at hiding. When I was a kid, one time my brother and sister and I were keeping a toad as a pet, in a cardboard box, and it escaped. For a couple of days we saw no evidence of it. But then in the middle of the night my dad got up to pee, went into the bathroom, turned on the light, looked into the toilet -- and there was the toad staring up at him. He made us get rid of it. Looie496 (talk) 22:04, 22 August 2013 (UTC)

Great story :) I hope the OP updates us if he finds it. SemanticMantis (talk) 01:40, 23 August 2013 (UTC)

In light of the above anecdote, might putting a pan of water someplace on the floor attract the toad? ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:31, 23 August 2013 (UTC)

Explanation for the acronym SWE

The phrase "SWE Stereo" appears on my television screen to reveal the audio utilized by a local TV station in their broadcast. The TV station is SLCCTV (Salt Lake Community College TV, channel 86-1701) located in SLC, UT. Directly below SWE Stereo is the resolution value "480i SD" (standard definition}. Thank you, Thomas J Tippett Tjtippett (talk) 19:10, 22 August 2013 (UTC)

Just a guess, but might it have something to do with Secondary Audio Programming? If you have an SAP button on your remote or set, try pressing it and see if you get Swedish. InedibleHulk (talk) 19:49, August 22, 2013 (UTC)

Another guess is it has something to do with this satellite terminal the station might use. Do you know if the station has any connection to the ABC 4 station? ABC is said to use this system. InedibleHulk (talk) 20:07, August 22, 2013 (UTC)

Effects of music while working & studying on performance

I listen to music several hours a day while studying (I'm a math student) and I wonder how much it affects my performances. Does the type of music (rhythmical/calm/powerful/..., vocal music or not, etc.) and genre (I hear mostly classical music and film soundtracks) matter? Thank you. 23:07, 22 August 2013 (UTC) — Preceding unsigned comment added by 84.109.248.221 (talk)

Mozart effect might be relevant. Googling "effect of background music" gave a few promising-looking links, including this (MS Word doc) on 'The effects of background music on learning, performance and behaviour' and this on 'The effect of background music and background noise on the task performance of introverts and extraverts'. AndrewWTaylor (talk) 08:35, 23 August 2013 (UTC)

I'm a high school teacher who moves around a bit between different schools. Just started in a new school for a four week stint. As usual, many students have asked if they could listen to music while they worked, insisting that they work better that way. (Some didn't ask, and DID listen. They won't any more.) Andrew - that study could be very useful. Might just print out that abstract for sharing with students. HiLo48 (talk) 09:28, 23 August 2013 (UTC)

It's a commons highschool science-fair project...comparing different styles of music (better students remember to analyze both style itself and alignment with subject's preference separately), different types of tasks, etc. It's rare that their background "research" consists of more than the popularized version of the Mozart effect--even if they cite the original study they obviously didn't read it--or any of the later publications strongly refuting the popular form. Sigh. DMacks (talk) 09:34, 23 August 2013 (UTC)

Temperature ranges of gas giant moons

When my teacher keeps telling me planetary composition, albedo, and atmosphere gases are also important to determine planet's and moon's surface temperature, I keep thinking these factors are not important. But Does the airless moon of gas giants have temperature ranges small or the global temperature of Jupiter, Saturn, Uranus' moon have wide temperature fluctuation between day and night. Enceladus (moon) Say the minimum surface temperature is 32 K and the maximum surface temperature is 145 K. I checked Europa (moon) it said the minimum surface temperature is 50 K and maximum surface temperature is about 125 K. --69.233.252.198 (talk) 23:12, 22 August 2013 (UTC)

You keep thinking the atmosphere is not important and keep being wrong. It's very important. To give you an idea, Earth's average surface temperature would be about 60 degrees Fahrenheit lower if the Earth didn't have an atmosphere. That's a significant change. Dauto (talk) 23:47, 22 August 2013 (UTC)

August 23

the shape of heart

Asked and Answered on the Maths Desk
The following discussion has been closed. Please do not modify it.
What is the geometric shape of the heart? Can I say that the heart is a truncated cone? (I do not think it is a truncated cone that is not really like that) — Preceding unsigned comment added by 46.210.149.99 (talk) 00:18, 23 August 2013 (UTC) For what purpose? In what context? μηδείς (talk) 00:28, 23 August 2013 (UTC) Let's presume the context is the human heart. Why does the purpose matter? Perhaps it's so that the IP can make a Heart-Shaped Box. --Demiurge1000 (talk) 02:06, 23 August 2013 (UTC) Kind of like a softball that's been hit a few too many times. ←Baseball Bugs What's up, Doc? carrots→ 03:12, 23 August 2013 (UTC) Is softball played much in Israel? CambridgeBayWeather (talk) 04:55, 23 August 2013 (UTC) Nah, they play strictly hardball. ←Baseball Bugs What's up, Doc? carrots→ 06:01, 23 August 2013 (UTC)

Breathing

If I inhale a mixture of gases called air which is 78.09% nitrogen, 20.95% oxygen, 1 % water vapour, 0.93% argon, 0.039% carbon dioxide, what mixture of gases do I exhale? Th4n3r (talk) 10:48, 23 August 2013 (UTC)

Amongst other things, it'll depend on your species, how long you held the breath, and the various physical conditions of your body. 86.141.186.4 (talk) 12:49, 23 August 2013 (UTC)

It depends on a great number of factors. Googling "rest oxygen consumption" returns a number of sites that give the oxygen consumption of adults as around 5% of what's available. It's converted to an equal volume of carbon dioxide. On this basis, the exhaled air will be 78.1 % nitrogen, 19.9% oxygen, 1.09% carbon dioxide, 1% water vapour, and 0.93% argon. Note that what you breaqth out is little changed from what you breath in, which is why mouth to mouth rescusitation works. Anything that increases metabolic rate will increase the conversion of oxygen to carbon dioxide - digesting a meal, physical exercise, thinking hard. Reacting to enviromental conditions will also increase it - for example shivering when cold. If you increase your body rate by either eating to much and getting fat, or building up muscle mass by exercise, your metabolic load increases but your lung volume capacity does not. (If you are quite obese, you lung capacity may be reduced, making you breath harder even at rest) Hence an increase in body weight will increase the percentage conversion of oxygen to carbon dioxide. Note that 1% water vapour in air represents 100% relative humidity at temperatures lower than 16 C, but only 20% rel humidity at 40 C. At the higher temperatures within the human comfort range, the body looses small amounts of water vapour to expired air. 1.122.214.154 (talk) 13:07, 23 August 2013 (UTC)

Don't forget that the water content will also increase; there's a lot of wet surface area inside the lungs. (The number above corresponds to only about 45% humidity at 20°C.) TenOfAllTrades(talk) 13:35, 23 August 2013 (UTC)

As is evident, especially in the winter, or when exhaling onto a glass surface. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:29, 23 August 2013 (UTC)

Alternative classification of Carnivora

Since not all Carnivora are in fact obligate carnivores and some are omnivores, is there some better and common (possibly unique) feature among them? Perhaps some taxonomists have proposed something on that? Brandmeister^talk 10:58, 23 August 2013 (UTC)

I would venture to suggest: their descent and relatedness. Linnean taxonomy used to be based on an ad-hoc mixture of visually obvious physical similarities, which taken in aggregate gave clues to organisms' actual relatedness (and were sometimes ambiguous or misleading), but nowadays it uses the much more rigorous methods of Cladistics, and can be corroborated by direct genetic comparisons. Characteristics that specific groups might have largely or uniquely in common are handy aide-memoires, but not ultimately definitive, because Evolution (if you'll excuse the trope). {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 12:53, 23 August 2013 (UTC)

Yes, ultimately ancestry is the real basis of classification. Often there are physical features that are highly characteristic, but they may not be obvious -- for example the layout of the teeth is often one of the most informative things. So is the bone structure of the foot. I don't know enough about this group to say anything specific, though. Looie496 (talk) 14:59, 23 August 2013 (UTC)

Yes, not all Carnivorans are obligate carnivores -- so what? As Carnivora indicates, the extant Carnivorans form a monophyletic group, which is about as good as it gets for modern cladistics/systematics. I'm not sure what feature they would all share, because the pinnipeds are a rather different from the rest. Perhaps there is some shared skeletal feature, but it would be pretty opaque to a non-specialist. As .195 says above, what they share is common descent. Conceivably, we could change the name to "Foofles", while keeping all members the same, but that would cause its own headaches. The way the International_Code_of_Zoological_Nomenclature works, names should follow the Principle of priority, unless there is some other good reason to change them (e.g. splitting an old paraphyletic group into two or more new monophyletic ones). Finally, beware the etymological fallacy! Hope that helps, SemanticMantis (talk) 15:03, 23 August 2013 (UTC)

Enemy locked onto heat signature; release flares

In the game Battlefield 3, one mission requires the player to occupy the gunner position in some sort of fighter aircraft. When the enemy locks onto the heat signature, a system of the aircraft occupied by the player warns the player and warns further when a missile is fired. The player is expected to release flares to thwart the enemy missile. How does the system recognise that the enemy aircraft has locked onto the heat signature? --89.241.229.123 (talk) 14:14, 23 August 2013 (UTC)

By what method does the attacker "lock on"? If it's via radio waves, those waves could be detected by the target vehicle's systems. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:28, 23 August 2013 (UTC)

Is the question about how the video game software operates this feature, or how its real-world counterpart works? Video games tend to use "omniscient software" that is aware of enemy moves, which simplifies the design and allows the creators to provide the desired user-experience.

In real life, a heat-seeking missile is not easy to detect. Because infrared missiles uses passive homing, they don't broadcast any type of strong signal. So the defending aircraft must use its own active RADAR to detect an unidentified object in the area; its onboard computer must calculate a trajectory and identify it as a potential missile; and then by deduction, it can be assumed to be a heat-seeker if it satisfies certain characteristics (size, velocity, RADAR signature - or lack thereof). This is an estimation problem that is prone to error and misidentification. Electronic warfare aircraft may escort fighter-aircraft in combat; these special airplanes carry more and better RADARs and computers (and other instruments) to help reduce error. Modern air doctrine emphasizes "Coordinated Command and Control" - enabling multiple airplanes, as well as ground and satellite facilities, to share combat information in real time, to help reduce errors in identification of unknown targets. Nimur (talk) 14:43, 23 August 2013 (UTC)

Is there any condition in which two vectors can be divided?

Is there any condition in which two vectors can be divided? Concepts of Physics (talk) 14:52, 23 August 2013 (UTC)

This is not a common terminology for any commonplace operation in engineering or physics. You can define many mathematical operators that have qualitative similarities to division and accept vectors as inputs. But most people who use those operations prefer to use a different, more precise term, like computing an inverse or left-multiplication by the adjoint matrix. Nimur (talk) 14:57, 23 August 2013 (UTC)

This was discussed at length a month ago. Red Act (talk) 15:04, 23 August 2013 (UTC)

This page shows division of two vectors. Is this method correct? Concepts of Physics (talk) 15:28, 23 August 2013 (UTC)

That is a correct example for R (programming language) where the term "vector" is understood to be a one-dimensional array and where division is done element by element. This is a different use of "vector" than Vector (mathematics and physics). -- 200.7.90.57 (talk) 15:52, 23 August 2013 (UTC)

Gap spanners on the International Space Station

What are the "gap spanners" that I read about astronauts installing on the International Space Station? The best I can find is that they are "used by spacewalkers to get from one module to another", but I can't find any details. Are they cables? Are they rods? What are they made out of? How are they attached? Are there any good photos of them online? -- 200.7.90.57 (talk) 15:30, 23 August 2013 (UTC)

the haert rate in different bodies sizes

What is the reason that the big body is with low heart rate and a small body is with high heart rate? In example: addult from 10 years and above has heart rate of 60-100 per minute while an infant (until 90 days) has heart rate of 80-205 per minute! The same things are in animals. In example: the elphent has 25 HR per minut while the mouse has about 500 heart rate per minuts! So, in short: Why does as much as the body smaller the heart has high heart rate? 95.35.239.134 (talk) 16:36, 23 August 2013 (UTC)