Revision as of 15:43, 14 February 2015

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

• WP:RD/S

Main page: Help searching Misplaced Pages

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

How do I answer a question?

Main page: Misplaced Pages:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

• Teahouse
• Help desk
• Village pump
• Help manual

February 10

water use comparison:production of gallon of milk vs gallon of soy milk vs gallon of almond milk

I'm wondering what comparisons of all 3 types are available. thanksRich (talk)`

Well, there's a great deal of inefficiency in converted plants into animals, so the cow's milk will take the most. I can't comment on whether soy milk or almond milk would be next.

Not interested in rice milk, coconut milk, cashew milk, etc. ? StuRat (talk) 00:24, 10 February 2015 (UTC)

All of those sound equally wretched. Are there any honest reviews of their taste to be found? ←Baseball Bugs carrots→ 03:41, 10 February 2015 (UTC)

I've tried most of them. They're not exactly the same as cow's milk, but they aren't bad. They seem to be selling well, so others must agree. (They also keep much longer than cow's milk, and anyone who ever drank sour milk will appreciate that.) StuRat (talk) 05:30, 10 February 2015 (UTC)

I've switched from cow's milk to almond and almond/coconut milk (we usually get "Almond Breeze"). While they definitely don't taste like cow's milk, they really aren't supposed to. So instead of saying "Do these fake milks taste like real milk" you should be asking "In what part of my diet can cow's milk be replaced with almond (etc) milk?"...something doesn't have to taste the same to taste good - and that's what we have here. When I occasionally drink cow's milk, the difference in flavor is very noticable - but still not objectionable. Baseball bugs should refrain from calling something "wretched" without trying them. They taste just fine...and they are VASTLY better for the environment than cow milk. The big open question for me is whether these plant-based milks can be used in cooking. So far, our very limited experiments say "Yes"...but I could easily imagine that not working out too well in every case. But for the three uses I have for the stuff (to dunk cookies into, to pour onto breakfast cereal and to whiten my coffee), the plant-based stuff works 100% perfectly as a substitute. Almond breeze also makes an almond/honey milk...I quite like it, but my wife didn't.

So much for the personal story...HERE are some results from what seems like a fairly careful analysis. It shows that all of the plant-based milks are at least 20 and as much as 50 times less "impactful" on the environment than cow's milk. It shows that coconut milk is better then almond which is better than soy. Personally, I find pure coconut milk to be too far from the 'mouth feel' of dairy - but I like the flavor - hence my choice to use the coconut flavored almond - or the pure almond. Sadly, that study didn't cover rice milk. I found it to be a little bland - so again almond/coconut wins for me. Coconut/almond chocolate milk is to die for...in my mind, the flavor is hugely superior to cow's milk.

So try a bunch of them - don't judge them for 'realism' versus cow milk, that's not the idea here and if you approach the problem with that mindset, they'll all fail. But if you're open to a new flavor...try a bunch of them before you settle on a couple of favorites.

Another observation I have is that cow milk doesn't taste the same everywhere...the stuff we get here in Texas tastes *WAY* different than the milk I drank in the UK. This again speaks to that "realism" thing.

SteveBaker (talk) 14:53, 10 February 2015 (UTC)

They did indeed seem to market all those products as milk substitutes initially. Putting "milk" on the label, putting it in similar half-gallon containers, and making it look like milk demonstrate this. But I agree that they can go beyond mere substitutes.

As far as cooking, cow's milk has the issue of foaming up and boiling over. Do those other "milks" do that ? If not, that sounds like a definite improvement. StuRat (talk) 15:04, 10 February 2015 (UTC)

The figures would likely depend significantly on where the products are being produced. It will also depend on what you're counting. For example, if cows are raised and fed mostly on a pasture which is mostly watered directly by the rain, are you counting that water? What do you do about the significant contamination of the water supply that may result from the cow effluent? (This can be a significant problem BTW, see e.g. Water pollution in New Zealand ). I know a number of people here hate the concept of Virtual water, I personally don't go so far, but I would say it has major limitations and does greatly oversimplify matters (similar to the concept of food miles for example). Nil Einne (talk) 01:39, 10 February 2015 (UTC)

strain guage load indicator

what is the use of strain guage load indicator and how is it used — Preceding unsigned comment added by 117.222.121.206 (talk) 08:46, 10 February 2015 (UTC)

See Strain gauge. The gauge measures strain, the relative movement of parts of a mechanical system under load. Tevildo (talk) 09:19, 10 February 2015 (UTC)

And using the strain reading and knowing the material involved, the forces acting upon the object can be inferred. Thus a strain gauge is one way to determine those forces, as in a strain gauge scale: . StuRat (talk) 14:58, 10 February 2015 (UTC)

Temperature profiles

I'm looking for datasets (e.g. CSV) for
a) earth atmosphere (like in File:International Standard Atmosphere.svg)
b) world oceans (like in File:THERMOCLINE.png)
temperature profiles. May anyone help?--Kopiersperre (talk) 13:08, 10 February 2015 (UTC)

NOAA is the place to go for this sort of thing, I think you can (in principle) make graphs like those from the data here . Track up a level here to get an overview and search, and also look here . I don't think they deal in CSV these days - the format is very cumbersome and space-inefficient for large data sets. One format they hand out is netCDF, and some instances of that are basically wrappers for HDF5 - if you are interested in this sort of thing, I recommend you learn how to handle those formats. Both can be converted to CSV (with a loss of structure and metadata) if necessary. SemanticMantis (talk) 14:33, 10 February 2015 (UTC)

I would like to have a something like a global mean. This shouldn't be too big for CSV. Thanks for the links!--Kopiersperre (talk) 14:51, 10 February 2015 (UTC)

Why did?

1) Why did natural magnetism of planet Earth always determines the possibility of the existence of all substances on the planet Earth, and could also determines the possibility of creating these substances in the natural environment of the planet Earth, so did that means the fact of physics that in case of changes of the natural magnetism of planet Earth many substances really cease to exist in the natural environment of the planet Earth, and other substances could not be created in the new conditions of the planet Earth?

2) Who discovered the Law of conservation of energy in this form of physical-mathematical formulas |F| = |-F|?--83.237.214.220 (talk) 15:54, 10 February 2015 (UTC)

I added numbers to your Qs:

1) The Earth's magnetic field supposedly protects the lighter elements and molecules (including water vapor) in the atmosphere from erosion due to the solar wind. This in turn protects the oceans, which might evaporate into space if there was no magnetic field. Without our current atmosphere or surface water, life probably would not exist on Earth. StuRat (talk) 16:03, 10 February 2015 (UTC)

"supposedly". Do you believe otherwise? 217.158.236.14 (talk) 16:44, 10 February 2015 (UTC)

It's instructive to note that Mars has had no magnetic field whatever for at least the last four billion years - yet it's believed to have had surface water as recently as two million years ago. This might reflect the amount of time that this theoretical atmospheric stripping and subsequent ocean evaporation might take...but I think this shows that it's not obviously true that we owe our atmosphere and hydrosphere to the magnetic field. Venus also has an almost non-existent magnetic field - and despite being even closer to the sun, has an exceedingly dense atmosphere - which also makes it hard to reconcile the idea that you need a magnetic field in order to have a dense atmosphere. Venus has no oceans, but that's because of the insane amount of heat caused by its runaway "global warming" problem.

So, I agree with User:StuRat that this explanation for the importance of the Earth's magnetic field is probable, a quick glance at our neighboring worlds suggests that it's not necessarily the case. SteveBaker (talk) 17:09, 10 February 2015 (UTC)

Yes, the Atmosphere_of_Venus and Atmosphere_of_Mars are good to look at, and show that a strong magnetic field is not a necessary condition for an atmosphere. It's a little bit unclear what precisely the OP is looking for, so I'll say this simply: We can say with near certainty that our planet's atmosphere is affected by its magnetic field. We can say with near certainty that atmospheric escape would be greater if the field were weaker. We can say with near certainty that our atmosphere would be different if Earth never had a magnetic field. It is nearly impossible to say exactly what our atmosphere would be like without a magnetic field. SemanticMantis (talk) 18:11, 10 February 2015 (UTC)

No, but it's theory, which can't be directly tested, so I don't want to refer to it as if it were a proven fact. StuRat (talk) 16:45, 10 February 2015 (UTC)

Dude, That is not what theory means in science, see scientific theory. A theory is not a hypothesis, but both can and are commonly tested. You should know better. I apologize for the emphatic text but this is important and you shouldn't be spreading harmful misinformation. The Theory of gravity is "just a theory", so is the Germ theory of disease. Both of these have been extensively tested, refined, and extended over the course of many years. I don't know much about Earth's_magnetic_field, but there are plenty of citations in that article. Additional info and references at Atmospheric_escape#Significance_of_solar_winds. I don't think there are is any serious contention about the fact that the Earth's magnetic field helps protect the atmosphere from solar wind. SemanticMantis (talk) 17:00, 10 February 2015 (UTC)

I didn't say no theory or hypothesis can ever be tested, only this one. As for gravity, it isn't exactly settled, either. Are gravitons real ? Is space-time really warped ? How do we combine gravity with the other forces and quantum dynamics to create a theory of everything ? StuRat (talk) 21:09, 10 February 2015 (UTC)

Did not you think that the properties of all substances in the nature of the planet Earth is always determined by the natural magnetism of planet Earth?--83.237.205.179 (talk) 17:05, 10 February 2015 (UTC)

The properties of substances isn't greatly affected by the nature of the magnetic field. Hydrogen and oxygen react to make water, which freezes at zero degC no matter where in the universe it happens to be - with or without a magnetic field. There are a very, very few cases where it does matter...but generally, no. What we're talking about with atmospheric and hydrologic stripping by the solar wind on planets without a magnetic field, we're talking only about which substances are present at the surface of the planet - not what the properties of those substances are. SteveBaker (talk) 17:16, 10 February 2015 (UTC)

2) Our Conservation of energy article has a "History" section that describes the discovery of the law - you can't really attribute it to any one person. The ancient Greeks (notably Thales and Empedocles) wrote about this idea and asserted it to be true. Galileo also believed in it and did some simple experiments to try to demonstrate it. Leibniz produced the first modern mathematical formulation...and at least a dozen others have had a large contribution to this concept. I'm not sure about |F|=|-F|...I have no idea what that's trying to say, or who said it. SteveBaker (talk) 16:59, 10 February 2015 (UTC)

How can be consider the Law of conservation of energy in this physical-mathematical formulation |F| = |-F| in the scientific nuclear physics?--83.237.205.179 (talk) 17:05, 10 February 2015 (UTC)

|F| = |-F| is a trivial consequence of the definition of | |. When we use that operator we're saying that only the magnitude of the quantity is relevant, not its orientation. But in a conservation law the orientation (direction of a vector or sign of a scalar) is vital, so | | does not belong anywhere near it. I hope this helps. —Tamfang (talk) 20:31, 11 February 2015 (UTC)

Mathematical value of the module in mathematics is always expressing the inverse proportionality of mathematical values, in this case |F| = |-F| be proving the mathematical identity (equality) of inversely proportional physical-mathematical units (values).--83.237.243.175 (talk) 15:49, 13 February 2015 (UTC)

How did the organs evolve?

When multicellular life got started, what organs were formed first? Count Iblis (talk) 21:28, 10 February 2015 (UTC)

I am assuming you are talking about multicellular animals, not multicellular organisms in general. For multicellular animals it is very likely that the first ones - similar to modern sponges - had differentiated cell types but did not have differentiated organs; see Parazoa. However, this is not known for sure, as the precambrian fossil record is quite sparse. Some of the earlies lineages of multicellular animals with differentiated tissues (see Eumetazoa) that survived until modern times are jellies, comb jellies, corals, etc.; it would probably be safe to assume that the first multicellular animals with differentiated tissues were similar to some of those, and possessed similar body plan and organs. Dr Dima (talk) 22:25, 10 February 2015 (UTC)

For some it was the mouth it was the mouth, for you it was the anus. μηδείς (talk) 02:30, 11 February 2015 (UTC)

You might like to check out the physiology of salps and other Tunicates. Of course we don't know exactly how the first organs arrived, but these critters are fairly ancient, and fairly primitive/basal. Medeis can't help but obscure helpful links in weird jokes, but I think the idea is that you might want to learn a bit about Evo devo as well. SemanticMantis (talk) 13:19, 11 February 2015 (UTC)

It's not really a matter of organs forming first, but gradually becoming more differentiated. In a very primitive organism the single cell is skin, digestive tract, muscle and sensory organ. With multicellularity, eventually "inside" and "outside" became distinguishable (ectoderm, endoderm) with mesoderm soon to follow (surrounding what you might call internal pockets of sea (coelom), protected spaces where gametes were released and the precursor of urine could be processed, usable hydrostatically as the first intimation of a skeleton. And each of these became more and more subdivided and specialized so that each activity had its own organ. But take any given enzyme from any given organ and there's a good chance you can find some relative in a protozoan. The activities are more separated than created. Wnt (talk) 15:19, 11 February 2015 (UTC)

There's also some fun stuff that is analogous to organs inside organisms, like the behavior of Dictyostelium_discoideum (note the "altruistic" death without reproduction of the stalk members), or even the sub-units within a superorganism. SemanticMantis (talk) 16:10, 11 February 2015 (UTC)

What is the evolutionary advantage in learning to control the anal sphincters?

^ 140.254.70.33 (talk) 23:59, 10 February 2015 (UTC)

Have you ever tried finding a mate while you're constantly crapping? Or tried to hide from a keen-nosed wolf? A regularly filthy ass and legs will attract flies, which have no problem breeding in your skin. That can outright kill, or just make sex even more difficult. Not a problem underwater or in the sky, but land-based furry critters should literally not shit where they eat. InedibleHulk (talk) 00:43, February 11, 2015 (UTC)

Somehow, cattle seem to do just fine with flies constantly buzzing around their fecal covered anuses. StuRat (talk) 00:46, 11 February 2015 (UTC)

They have the wherewithal to lift their tail first and aim as far away as they can (not very). And that tail can keep the flies away from ground zero. If they shit in their sleep, it wouldn't be so tidy. InedibleHulk (talk) 00:54, February 11, 2015 (UTC)

As usual StuRat is talking crap. Mulesing might be a bit of fun for him, I doubt the animal regards it as 'just fine'. Greglocock (talk) 04:30, 11 February 2015 (UTC)

Perhaps somebody needs to explain to you the difference between sheep and cattle ? Sheep tend to have thick covering of wool, which seems to be the cause of the problem your talking about. I was talking about cattle, which do not have a thick covering of wool. See the difference ? StuRat (talk) 04:40, 11 February 2015 (UTC)

I'm sure you are an expert on cow's anusses, but gthids guy appears to differ https://books.google.com.au/books?id=PbEWJrEtECIC&pg=PA323&lpg=PA323&dq=maggots+cattle&source=bl&ots=eQkvrA4hCM&sig=_dUy2bJUxWQ5I8bAxwF53w7KVzo&hl=en&sa=X&ei=v_naVP-CDo_W8gW564KIBQ&ved=0CDQQ6AEwBA#v=onepage&q=maggots%20cattle&f=false

Greglocock (talk) 06:43, 11 February 2015 (UTC)

Or, to put that another way, https://books.google.com.au/books?id=PbEWJrEtECIC&pg=PA323 —Tamfang (talk) 20:21, 12 February 2015 (UTC)

The mighty yak might feel slighted by your oversight, were he not mighty. Also, did you know there's a SugarRat on Misplaced Pages now? You two should hook up. InedibleHulk (talk) 05:12, February 11, 2015 (UTC)

1) Limits the spread of disease, especially if they defecate in an area far from where members of their species eat or drink.

2) Make it harder for predators to track them.

3) If they are predators, makes it easier for them to sneak up on prey.

Burying feces helps on all counts. However, I don't go along with the idea that the evolution of anal sphincter control has any effect on mating success, since any species which lacks anal sphincter control will also not care if potential mates smell like feces. Heck, even though dogs have such control, they still seem to enjoy the smell (and even taste) of feces. StuRat (talk) 00:49, 11 February 2015 (UTC)

Whatever the personal kinks, survival itself helps a lot with getting laid. Even if you're not dead yet, most potential mates should be able to spot the flaws in your setup. Not for my kids, she'll say. InedibleHulk (talk) 00:57, February 11, 2015 (UTC)

Also, a bunch of crusted dung over the old gene socket doesn't help the physical probabilities. Sure, she could keep it cleaner, but that's just less time spent on eating, hiding and raising kids. An ounce of prevention is worth a pound of cure. InedibleHulk (talk) 01:00, February 11, 2015 (UTC)

Primates are also pretty notorious for using feces as a weapon... and not just in the Special Housing Unit. For that they need to be able to produce it on demand. Also I imagine that there are some advantages to not crapping on the tree trunk you have to climb down, or which a predator could climb up. Admittedly all rampant speculation... not sure how you'd answer a what if like this with any confidence. Wnt (talk) 01:34, 11 February 2015 (UTC)

It's very easy. InedibleHulk (talk) 01:36, February 11, 2015 (UTC)

Sloths' defecation habits are a bit hard to understand. They climb down the tree (very slowly), defecate, then climb back up (slowly again), vulnerable to predators when on the ground. Wouldn't it be a lot safer to just let fly from the tree ? StuRat (talk) 01:39, 11 February 2015 (UTC)

Isn't that exactly how Ohio State students do it? μηδείς (talk) 02:28, 11 February 2015 (UTC)

Maybe if you made a habit of going to the bathroom. Sloths can go fifty days before thinking they shouldn't have had Mexican food (average of "only" sixteen, though). They'd make nature's worst drug mules, even moving at airspeed. InedibleHulk (talk) 01:48, February 11, 2015 (UTC)

Though, considering they eat between poops, they have to go for that long walk about once a week. Still, not bad. As long as they don't do it on the same day, every week. That's asking for trouble. (My apologies for presuming animals used calendars.) InedibleHulk (talk) 01:53, February 11, 2015 (UTC)

As for dogs and cats, their population and diversity explosion is directly tied to their adoption as pets, and that's hugely contingent on their housebreaking skills. Without a vigilantly puckered butthole (WARNING: contains butthole), man's best friend and woman's pretend child would be confined to the academic section of the Internet, instead of driving the bus. InedibleHulk (talk) 03:25, February 11, 2015 (UTC)

It is wrong to assume that because an organism has a trait, that that trait confers an evolutionary advantage. Everyone repeat after me: "Not all traits are adaptive traits." The better way to phrase this type of question is "Is there an evolutionary advantage?" SemanticMantis (talk) 14:47, 11 February 2015 (UTC)

That depends. If it's a trait that must exist, like eye color (even if it's just the pink eyes of an albino), then you're correct, every animal must have this trait (provided that they have eyes, of course). But an optional trait, with a cost associated with it (in this case increased weight and therefore slower movement due to retained feces) is never going to evolve unless it confers some advantage. Now, conditions could change, such that a trait, once evolved, is no longer advantageous, but that's a different matter. StuRat (talk) 15:15, 11 February 2015 (UTC)

No, it doesn't "depend". One more time, repeat after me: Not all traits are adaptive traits - there's no equivocation, no caveats, and no exceptions. Your notion of "optional trait" has no usage in evolutionary biology. There is also no such thing as a necessary trait. Genetic drift is a real thing. Some traits confer advantages, some confer disadvantages but also advantages, we often describe this in terms of Trade-offs. But some traits have no measurable affect on reproductive success and hence no real affect on evolution. Figuring out how this all pans out is very difficult, and people usually study it for several years before they go around saying they can explain the fitness benefits of a certain trait. Sometimes it's very context dependent, and fitness will depend on the concentration of other traits in the population, as in the now classic example of the mating habits of the Common_side-blotched_lizard, which use a sort of round robin mating strategy. Finally, even eye color can affect reproductive success through sexual selection. You can speculate about advantages of sphincter control all you like. I get it, it's fun to speculate about fitness, morphology, and behavior. But it's just speculation until you find a reference to a peer-reviewed study, or publish one yourself. SemanticMantis (talk) 16:05, 11 February 2015 (UTC)

So it's your contention that animals may have evolved the ability to control defecation despite it having absolutely no evolutionary advantage ? Wow, just wow. And are you also denying that carrying feces around has a disadvantage (which then would require a corresponding advantage) ? StuRat (talk) 16:14, 11 February 2015 (UTC)

The point is the OP is asking the wrong question. It's always a bad idea to ask the wrong question, since it can easily lead to the wrong answers, and at the very least, understanding why you're asking the wrong question can often be more important than knowing the answer to the question. Nil Einne (talk) 18:09, 11 February 2015 (UTC)

Back to advantages: I believe some animals defecate when being chased, in the hopes that it will distract the predator long enough for them to escape. StuRat (talk) 16:14, 11 February 2015 (UTC)

The emergency defecation is a means of lessening the weight load of the fleeing prey and of disgusting the predator. μηδείς (talk) 04:38, 12 February 2015 (UTC)

And, of course, the skunk has taken its ass to a whole new level of anti-predator adaptation.

Here's an academic paper on whether holding it in is an evolutionary advantage for humans. InedibleHulk (talk) 23:41, February 11, 2015 (UTC)

At least for modern humans, it's quite an advantage, since it allows us to use sewage treatment systems (and before that, latrines and septic tanks), which have greatly reduced the incidence of many infectious diseases and increased life expectancy dramatically. (Although perhaps we would all wear diapers by now, if we all had fecal incontinence.) StuRat (talk) 04:46, 12 February 2015 (UTC)

February 11

Cross Reaction Drugs Petri Dish pictures

I have searched & searched the www & cannot find one petri dish picture of a drug cross reaction (i.e., Aspirin, etc.c)& only found 2 that are "reaction" it should like the one drug is reach across the petri dish to the other.

Thank you,

Cynthia Privitera, RN, BSN, MSN, APRN, FNP-BC Nursing Faculty Nevada Career Institute — Preceding unsigned comment added by 65.223.25.38 (talk) 01:05, 11 February 2015 (UTC)

Could you explain a bit more what you mean? Maybe I should see it but I didn't. You make me think of Ouchterlony double immunodiffusion but I'm pretty sure that's not what you want. (maybe someone else understands though) Wnt (talk) 01:31, 11 February 2015 (UTC)

Do you mean where one drug kills some of the bacteria in a circle around it, and another kills some of the bacteria around it, but at the intersection almost all the bacteria are dead ? StuRat (talk) 01:41, 11 February 2015 (UTC)

We have an article about the agar diffusion test, which is the type of test you describe, albeit for a single compound to test. It sounds like (similar to StuRat's idea) you mean to have disks of different individual agents, and see if there are unusual effects where their diffusion overlaps (enhanced or reduced effectiveness compared to the simple additive effects of the two agents individually). I found some references to "double disk synergy" tests, eventually landing at PMID 18322055 and PMID 23543257, each of which have some pictures. DMacks (talk) 06:01, 11 February 2015 (UTC)

Dirt blower

Is there something similar to a snow blower, but grinds up dirt and rocks instead and accelerates them in a powerful collimated jet? 69.121.131.137 (talk) 02:14, 11 February 2015 (UTC)

• There's a leaf-blower and a garden hose, as well as a sand-blaster. If your goal is to ping the neighbors' house, see bb-gun. Google is your friend. μηδείς (talk) 02:22, 11 February 2015 (UTC)

• A wood chipper would work for dirt, but big rocks would be a problem. For those you'd need diamond or corundum blades. And getting the materiel into the wood chipper would be problematic. If you don't just want to drop the items in, you'd then need a device to dig it up and put it in the chipper for you. StuRat (talk) 02:40, 11 February 2015 (UTC)

Did you check Crusher? A snow blower is dangerous enough when blasting out the snow. I suspect that a rock blower would be somewhat worse. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:44, 12 February 2015 (UTC)

How can those Flicker 3 Wheel Scooter move uphill?

Or move at all at a flat surface. I wonder how skate boards can do it too, BTW. See ] if you don't know what I mean.--Noopolo (talk) 02:22, 11 February 2015 (UTC)

Trikke works pretty much as skating does. Jim.henderson (talk) 02:31, 11 February 2015 (UTC)

Or skiing or skateboarding. In all such cases, you could build up enough momentum to get over small hills, but long, steep hills would indeed be a problem. The easiest way in those cases would be to get off and walk/push. StuRat (talk) 02:36, 11 February 2015 (UTC)

I'm pretty sure the OP is referring to climbing a long (but probably shallow) hill using a trikke, not just relying on momentum to get over a small hump. Our article suggests it's possible, as does a simple search. You don't have to get off, the whole point of the trikke appears to be that you can propel it without getting off, the same way you can with a bike (although the way you do it is quite different). It's perhaps worth remembering there's noting that unique about hills. If you can propel yourself forward on a e.g. flat surface from a standing start (or gain speed if not a standing start) without relying on gravity or the wind or something, then you just need to be able to generate enough force to counteract the effect of gravity (and the wind) going up a hill. Nil Einne (talk) 15:19, 11 February 2015 (UTC)

Just like with a one-speed bike, there is a certain steepness of hills where you can't go up anymore, and have to get off and walk. There is also a point before that, where it becomes easier to do so. Similarly, there's a reason you don't often see people skiing up steep hills. StuRat (talk) 15:26, 11 February 2015 (UTC)

But the point is you're generating the force to climb a hill. Talking about building up momentum to get over a small hills is confusing since it sounds like you're referring to simply relying gravity from long down travel which is clearly not what's being referred to. Whether with a bike, or with a trikke, in both cases you can successfullly climb a long (albeit probably shallow unless you're very good) hill if you have the stamina without needing to get off. Nil Einne (talk) 15:32, 11 February 2015 (UTC)

No, not enough kinetic energy at the bottom of the hill to carry you to the top. That's clear from the video I shot for the Trikke article, when I chanced upon it while bicycling. At the end of each zig, the legs push so the vector of momentum will point to the opposite side, to carry the rider through the zag. Not as efficient as a roller skater climbing a hill, but similar in principle and effect. Workable, though I prefer the benefits of the more mechanically complex pedaling action. Jim.henderson (talk) 15:29, 11 February 2015 (UTC)

Power electronic

What is power electronic? — Preceding unsigned comment added by YogR9923 (talk • contribs) 09:05, 11 February 2015 (UTC)

Likely this is Power electronics the use of electronics for the control and conversion of electric power. (I have done a course in this if you have more specific questions). Graeme Bartlett (talk) 10:26, 11 February 2015 (UTC)

Or it could just be a redundant way to refer to any electronics, particularly if they want to make them sound more impressive: "The all new XL9000 features power electronics to get any job done quickly !". StuRat (talk) 15:29, 11 February 2015 (UTC)

power electronics is also a genre of highly disturbing electronic music. One of the most popular of these groups is called Whitehouse.99.61.19.139 (talk) 02:00, 12 February 2015 (UTC)

Is the Law of conservation of energy being the absolute law of physics?

1) Is nuclear physics being the physics of ideal situation – the physics of ideal model, that is, whether is all cases of nuclear physics being the ideal cases of physics?

2} Why work (energy) of electrons of nucleus of an atom is not being observed in other sections of physics, if the Law of conservation of energy is always being the universal law of physics (nature), that is, if the Law of conservation of energy is always being observed in physics (nature)?--83.237.223.123 (talk) 09:40, 11 February 2015 (UTC)

1 - nuclear physics is not so useful for explaining many other physical phenomena, eg acoustics optics. However I think you need to ask question 1 again as I donot understand. Graeme Bartlett (talk) 10:24, 11 February 2015 (UTC)

2 - The energy of electrons in an atom results in chemical energy. The law of conservation of energy applies to this too, and changes to these electrons may result in heat, or light energy being produced, eg a burning candle. Graeme Bartlett (talk) 10:24, 11 February 2015 (UTC)

Much thanks! If the same physical phenomena could be physical-mathematically described by different ways, whether are these laws of physics and also mathematics identical (equal) to each other, if for example the work (energy) of electrons atom's nucleus is unstable in different sections of physics?--83.237.192.148 (talk) 11:05, 11 February 2015 (UTC)

Did the ideal case of physics being identical (equal) to particular case of physics, that is be, did the physical-mathematical values in physics are proportional to each other?--85.141.236.139 (talk) 12:34, 11 February 2015 (UTC)

We do not know. The latest articles seem to say the Big Bang was impossible as a result of quantum mechanics - which means a lot of theorists are working overtime. For all reasonable purposes for anyone else, conservation of mass and energy seems to work fine. Collect (talk) 15:19, 11 February 2015 (UTC)

The quantum Big Bang is impossible due to the fact that quantum physics is a special particular case of nuclear physics!--83.237.215.225 (talk) 17:48, 11 February 2015 (UTC)

Since the physical-mathematical values are dependent on each other, so this gives claim that physical-mathematical values are proportional to each other, is it correct?--83.237.215.225 (talk) 17:48, 11 February 2015 (UTC)

Did the natural magnetism of the planet Earth as a physical outside working body - the energy, always doing work on conservation of the balance of energy in the nature of the planet Earth, thus achieving absolute compliance with the Law of conservation of energy in all applications in the physical and chemical models?--83.237.215.225 (talk) 18:35, 11 February 2015 (UTC)

From last to first, third, the natural magnetism of the Earth, see Earth's magnetic field, which does respect conservation of mass-energy, and has complex causes due to motion and electricity in the Earth. Any effects that the magnetic field has on objects in its magnetic field will affect the Earth's rotational kinetic energy and rotational angular momentum; because the Earth is so much larger than any other objects affected by its magnetic field, the observable effect will be minimal. (This is also true of the effect of the Earth's gravitational field on small orbiting objects). Robert McClenon (talk) 18:50, 11 February 2015 (UTC)

Second, it is true that the Big Bang appears to violate the law of mass-energy, and, as previous posters note, this is a matter of theoretical attention. However, it is not clear what set of quantum equations apply "before" or "at" the Big Bang, so that it is not obvious how to quantify mass-energy "before" or "at" the Big Bang. Robert McClenon (talk) 18:50, 11 February 2015 (UTC)

First, it is the best scientific thinking that the law of conservation of mass-energy is absolute. (That is not the same as the classical law of conservation of energy or the classical law of conservation of mass, because relativity provides that energy and mass are interchangeable, or two ways of stating the same quantity.) Robert McClenon (talk) 18:50, 11 February 2015 (UTC)

Please review these answers and see if your question has been answered, or if you meant to ask some other question. Robert McClenon (talk) 18:50, 11 February 2015 (UTC)

Sincerely thank you, unfortunately I did not know that there is be a kinematics of mass, as because always believed that in nature there is only be the kinematics of accelerations, so that I did not consider that the physical-mathematical units (values) of mass any way being proportional to physical-mathematical units (values) of work (energy), so I think that applied mathematics is always be a weak point of theoretical physics.--83.237.201.24 (talk) 08:45, 12 February 2015 (UTC)

Believed, that the Law of conservation of energy is always retains the gravity of mass, but not the same physical mass.--83.237.201.24 (talk) 09:00, 12 February 2015 (UTC)

We could assume that some of the mathematical and physical units (values) did not had a values, that is being, these mathematical and physical units (values) are always being a dysfunction of mathematics.--85.141.232.219 (talk) 10:41, 12 February 2015 (UTC)

It could be assumed that the value of identities (equals) in mathematics and physics always detects the presence of an absolute, but not relative possibility of solving mathematical and physical problems (tasks) as well as the identity (equally) in mathematics always detects the presence of capabilities of the mathematical solving, thus proving the identity (equally) of the mathematical proves the possibility of being the some mathematics and physics absolute units (values)!--85.141.237.211 (talk) 13:23, 12 February 2015 (UTC)

As a result, there is be a absolute identity (equally) between each other of the some physical-mathematical units (values), which constantly absolutely expressing the physical-mathematical and physical-chemical values of the potential of energy in nature, these it be the accelerations, pulses, work, forces, pressure and other absolute.--83.237.197.203 (talk) 15:41, 12 February 2015 (UTC)

Believe, that in physics the resting state of any body is always being a particular case of motion (displacement) of bodies, so that in physics the potential energy and identity (equally) to her a physical-mathematical units (values) are always being a particular case of the kinetics.--83.237.216.207 (talk) 18:53, 12 February 2015 (UTC)

In physics, the identity (equality) of accelerations to each other, is always determining all cases of balance of the Law of conservation of energy in nature.--83.237.222.238 (talk) 08:56, 13 February 2015 (UTC)

Hi. To find answers to this thread's titled question see conservation of mass-energy, but I'm afraid that the article is not likely to be of much help to you because of your abstract beliefs, although devoid of the necessary mathematics here, have led you to believe that energy conservation is absolute. That is fine of an answer too. -Modocc (talk) 18:32, 13 February 2015 (UTC)

Unit of mass

Can mole (unit) be in some situations a unit for mass? This seems to follow from the description of mole as the amount of substance whose mass in grams is numerically equal to the relative molecular mass of that substance.--92.81.43.185 (talk) 10:54, 11 February 2015 (UTC)

Sure, if you specify the substance, and specify that it's pure, then saying you have one mole of it also determines how much mass the sample has, provided that we know the mean molecular mass. But just because molar units can be used to calculate mass, doesn't mean that it is a unit of mass. A gram is a gram, no matter if it's a gram of water or iron. But a mole of iron and a mole of water have very different masses. From the article: "The number of molecules in a mole (known as Avogadro's constant) is defined such that the mass of one mole of a substance, expressed in grams, is exactly equal to the substance's mean molecular mass". Moles are often used as units when describing chemical reactions, because the number of molecules is important in determining what happens. If you actually want to tell someone the mass of something, just use a mass unit :) SemanticMantis (talk) 15:13, 11 February 2015 (UTC)

By the same argument cubic centimeters (a measure of volume) can also be a measure of mass in some situations. That might be valid in some formalistic sense, but it's a bad way of thinking and is best avoided. Moles are dimensionless. Looie496 (talk) 15:45, 11 February 2015 (UTC)

A mole can be said to have mass no more than a million can be said to have mass. A set of a million atoms of Carbon-12 has some specific mass that is equal to some non-round number, a set of a mole of atoms of Carbon-12 has a specific mass that is equal to 12 grams. The roundness of the result in the second case doesn't change the fact that both 'a million' and 'a mole' are just numbers. --Noren (talk) 20:24, 11 February 2015 (UTC)

Sanitary whole house humidifier ?

I'm asking about the type that attaches to the furnace, where hot air is blown through a filter that's kept soaked with water, and that humid air is then distributed through vents to the house. The problem is that all sorts of microbes, contained in that air, are blown through that warm, moist filter, allowing the nasties to grow on it, then send their spores throughout the house.

So, what's the cure ? Any type of chemical disinfectant seems to be out, because then that disinfectant vapor would spread throughout the house. Could a UV light work ? I doubt if the light could get everywhere inside the filter, but it might help a bit. I suppose we could just abandon the whole-house humidifier and boil water and use individual room humidifiers, but that's a major inconvenience (and risk, in terms of the pot boiling dry). StuRat (talk) 16:51, 11 February 2015 (UTC)

The big problem is Legionnaires' disease. Protocols (that in the UK are legally binding) have be drawn up: The control of legionella bacteria in water systems--Aspro (talk) 17:32, 11 February 2015 (UTC)

Do you already have such a humidifier? Humidity is never a problem in NYC, since steam heat is near-universal. But my parents have a house-humidifier and my dad cleans it and consults the manual. If you know the company, they should have a FAQ website and an 800 number.

PS, I can very highly recommend the http://www.walmart.com/ip/Vicks-Warm-Steam-Vaporizer which is only $14.95. It runs by boiling the water with an electrode placed in the top of the tank, and stops running when enough water has vaporized so that the electrodes are no longer submerged. No spraying of droplets, no risk of infection. μηδείς (talk) 17:34, 11 February 2015 (UTC)

Vicks sells this model so cheap because they expect you to add menthol or whatever they sell separately, which of course you need not do. Also, you have to prime the water the first time and each time you empty it with two pinches of salt, to allow the water to conduct electricity. (I don't empty it often. I just bring a new pitcher of water, which is easier to carry and fill than the tank.) And because it is an electric current, you'll eventually get a build-up of precipitate of whatever metals are in your tap water.

Those are room humidifiers, not whole house humidifiers, which means buying multiple units and refilling each daily, and occasionally cleaning scale off each. I want a "set it and forget it" system. And yes, we already have a whole house humidifier, and I want to know how to keep disgusting things from growing on it. StuRat (talk) 20:04, 11 February 2015 (UTC)

Yes, StuRat, they do need refilling daily if the house stays dry, but unless you have your windows open during cold weather, they work quite well, and three of them is strategic areas will cover most homes where cost is a consideration. Going to a nearby sink with a pitcher is no worse than having to set a thermostat and pay a specialist or do the cleaning grunt work as if you were a real man, born before the internet.

I spend most weekends and holidays at my parents', and have the largest room in the house, which is an attic guestroom with only the floor and one wall contiguous with the house, as opposed to the outside cold. It has central heating, but if I leave the vents open it becomes like a convection roaster. So I close the vents and put on the variation of the Vicks humidifier I linked to above I bought about 10 years ago for $9.95. The humidifier both heats the room and humidifies it, and only needs to run every other day t keep the room cozy.

One in the bedroom, one in the kitchen, and one in the laundry room will serve most homes. Otherwise, the option is either a new, heavy-duty humidifier to go in the furnace room that produces steam (i.e., sanitized water gas) and is drawn through the house, or call your current manufacturer. μηδείς (talk) 21:11, 11 February 2015 (UTC)

How many units you need would depend on the house size and insulation, outside dew point, and how often the doors are opened. StuRat (talk) 23:41, 11 February 2015 (UTC)

Well, of course, StuRat, I understand the variables. I would recommend you buy one (it's only $14.95 when not on sale!) and try it out. They really are wonderful humidifiers. My parents live at the SJ highpoint (well, close to, google the west end of the AC Expressway) and there's no Great Lake to lessen their drought. In fact, I asked my dad just last week why he doesn't leave his wooden door open and his glass storm door shut on sunny days (a front doorway, with a due south view) and he said it was due to the loss of humidity. He and my mother complain endlessly about how bad the house humidifier is for all the labor Dad puts into it. μηδείς (talk) 04:31, 12 February 2015 (UTC)

Here's an article from the EPA: (bottom line: follow the manufacturer's directions)  —71.20.250.51 (talk) 20:36, 11 February 2015 (UTC)

Wow, they suggest changing the water daily and scrubbing every 3 days, for portable humidifiers. That's a heck of a lot of work. I see there's room out there for a better design. StuRat (talk) 15:52, 12 February 2015 (UTC)

A low maintenance and safe option is a "flow-through" humidifier tho costly to buy and get installed. Here is a site explaining it tho you could search for more info about 2 other main systems out there if you wish. here they explain the systems available. If you don't want to invest in expensive systems like those, you can place a pan or water soaked pad in the hot air vent's path but you'll still have to replace and/or clean (disinfect) the tray and/or pad at least once a month. You should have at least 2 sets of pads so you can clean one (using bleach or another disinfectant detergent) and install it dry when needed.TMCk (talk) 23:53, 12 February 2015 (UTC)

That's the type we have now. The tap water flowing through provides minerals, the furnace provides heat, the air blown through provides the mold spores, and the filter provides a nice scaffolding for the to grow on. Put them all together and you have a paradise for mold. StuRat (talk) 06:14, 13 February 2015 (UTC)

Schuko plugs with smaller pins

I used to own two or three electrical appliances which had a Schuko-like plug with smaller pins (I bet they were 4.0 mmm instead of 4.8 mm). All the other features were the same as usual (guiding notches, lateral grounding and so on). Could they have been Russian GOST plugs?--Carnby (talk) 18:51, 11 February 2015 (UTC)

See AC power plugs and sockets and GOST 7396. The GOST standards do define a version of the CEE 7/17 plug (which is a hybrid between the French CEE 7/5 and the true CEE 7/4 Schuko) with 4mm rather than 4.8mm pins, although it doesn't (apparently) have a separate type number in the GOST system. Tevildo (talk) 19:26, 11 February 2015 (UTC)

How to power a cell-phone through a USB connection instead of the battery.

I have a cell-phone with a battery that's almost dead (30 min. running time at best). I use this cell-phone as a 3G modem, but it cannot be operated without a battery although it is connected to a USB port. The battery has 4 contact points, and I wonder whether I could connect a USB cable to two of these contact points and power it through another USB port. — Preceding unsigned comment added by Fend 83 (talk • contribs) 19:49, 11 February 2015 (UTC)

What happens when you use the phone with the battery installed and with the USB plugged in at the same time ? (Hopefully, it will charge the battery as quickly as it discharges, so it will never go dead.) StuRat (talk) 19:54, 11 February 2015 (UTC)

Not really. It goes dead but in takes longer than 30'. It has to be recharged then with the original charger. Apparently USB charging is weaker than that. Anyway, I imagine that this battery will get weaker and weaker and then stop working all completely in the future, so I need to find an alternative to it. — Preceding unsigned comment added by Fend 83 (talk • contribs) 20:02, 11 February 2015 (UTC)

No, USB is 5 volts, cell phone batteries are usually ~4 V. So at some point between the charger and the battery, there's a DC-DC converter to reduce the voltage. Do you have it plugged into a computer or an AC-USB adapter? The maximum current on a computer USB port is <1 A, but AC adapters can deliver 2 - 5. Most phones can handle a higher current, so they'll charge faster with a AC adapter than in a computer. Mr.Z-man 20:14, 11 February 2015 (UTC)

Mine is 3.7 V 750 mA. Can't you just use a resistor to do this drop of voltage?--Fend 83 (talk) 21:29, 11 February 2015 (UTC)

Good advice. Also, sooner or later you need to replace that old battery. There should be a model number on the battery. If you do a Google search on that, I'll bet you will find replacement batteries for sale online, even if the phone model is discontinued. One warning, though, is that they tend to sell batteries as "new" which are many years old, but presumably have never been used. I got such a battery, and it was a definite improvement over the old battery, but still not as impressive as a genuinely new battery would be. StuRat (talk) 20:28, 11 February 2015 (UTC)

The idea was to use the phone without battery as a cheap 3G modem. Otherwise, I could save the battery price and buy a pen-drive modem.--Fend 83 (talk) 21:29, 11 February 2015 (UTC)

It might be cheaper than you think, if there's a surplus of batteries for a now discontinued phone model. (This is payback for making every cell phone battery unique.) StuRat (talk) 23:44, 11 February 2015 (UTC)

• Fend 83 should call the phone and computer csr svc hotlines and ask about this, rather than return to us saying his computer has shorted out and his phone's on fire, along with the curtains. μηδείς (talk) 20:52, 11 February 2015 (UTC)

The problem with the idea of connecting the USB to the terminals of the battery compartment is that batteries are a lot more than dumb AAA dry cells. Most of them have all sorts of internal components that do things like measuring charge and internal temperatures. When you get rid of all of those thing, the phone's main computer is going to be upset. So this might require more complexity than you imagine to get it to work. The other thing that the battery does is to allow the phone to temporarily use more power than the USB can provide....and then pay for that later by using less power and having the excess recharge the battery. By evening out the peaks and troughs of usage, the phone can gradually take energy saving measures when it sees that the battery is getting low - which is a lot easer than predicting the instantaneous demand a millisecond into the future and minimizing the current draw to avoid overloading the USB and dying.

Sadly, your phone needs it's battery...and you're probably doomed without it. SteveBaker (talk) 21:42, 11 February 2015 (UTC)

I don't quite follow your setup. Is the USB connection necessary for your modem setup, or is it used only for power? If it's used only for power you have some possibilities for getting more current. Short Brigade Harvester Boris (talk) 03:11, 12 February 2015 (UTC)

Yes, I can get some power, but the cell-phone consumes more than can be recharged through an USB during use. After that I have to use the charged and stop using the cell-phone as 3G modem.Fend 83 (talk) 11:03, 12 February 2015 (UTC)

Apologies, my question was unclear. Is the USB cable necessary for transmitting data through your modem connection, or is it used only for power? Short Brigade Harvester Boris (talk) 13:19, 12 February 2015 (UTC)

Yes, it gets data through the cable. Although a blue tooth connection could be established too.Fend 83 (talk) 18:52, 12 February 2015 (UTC)

• According to the WP Disclaimer, we do not give professional advice that may end up in death, severe injure, or catastrophic property damage. μηδείς (talk) 04:22, 12 February 2015 (UTC)

Yes, please don't make connections that bypass the safety circuitry. Would a powered USB hub provide the necessary current? I would guess that 2000ma (10 watts) should be sufficient for your phone, but you can get more powerful ones if your phone is particularly power-hungry. Dbfirs 13:26, 12 February 2015 (UTC)

Semi-educated opinion here: As mentioned above, a powered USB hub might do the trick. I'd try a USB 3 hub since it should supply more amps per port. Bypassing the battery by connecting a power supply directly should be only done by someone with knowledge as you'd need not only make the right connection but also having the right and steady voltage to prevent the phone going into charging mode. Otherwise the unit can malfunction like overheating and even explode in a worst case scenario. Don't think you want to wear protective gear and having a fire extinguisher ready to use while surfing ;) TMCk (talk) 23:05, 12 February 2015 (UTC)

Just to share personal experience with people saying their batteries do not hold a charge long enough, I tell them to turn their phone off and on (reboot, restart etc) before or after charging. Every time the battery last longer. I suspect phones with poor design have processes that start and never stop and do nothing but use up charge. Richard-of-Earth (talk) 19:50, 13 February 2015 (UTC)

Yes, it's surprising how many processes can be running in the background. GPS and WiFi also use up battery power. You can download a process monitor that can check and terminate unwanted processes (but then, it's another process to run!) Dbfirs 08:45, 14 February 2015 (UTC)

Research papers

When writing a research paper do you need to go into the theory when justifying methodology? For example, if you added a catalyst to a reacting solution, you would justify the addition of the catalyst but is it necessary to go into the chemistry of it if the addition of the catalyst is simply to speed up the process and not part of your investigation. 194.66.246.4 (talk) 19:51, 11 February 2015 (UTC)

It might be nice to either add it as an addendum, or else provide a link to where it is explained. StuRat (talk) 19:56, 11 February 2015 (UTC)

I'd say it would depend on how common the practice is. If it's something that everyone else working in the field does or something that people have been doing for decades, a citation to an earlier paper describing it would be sufficient. If it's something that only your lab does or is rather new, you may want to add some additional explanation for people unfamiliar with it. How important it is to the actual findings would also be relevant - was it for some minor intermediate step in a long process, or was it the most important part? If you went into the theoretical detail about every part of your methodology, that section would be longer than the rest of your paper. Mr.Z-man 20:07, 11 February 2015 (UTC)

It was a minor part of a very long experimental procedure. Is it also common practice to put safety precautions taken in the methodology? 194.66.246.4 (talk) 20:28, 11 February 2015 (UTC)

Safety is not normally seen in papers unless the risk is extreme or unusual. eg 20 mg of the product will explode. (so make less than that). Safety will be part of the methodology, so the same applies above, document it if it is unusual or affects your results. Graeme Bartlett (talk) 21:30, 11 February 2015 (UTC)

Check with your journal or editor for guidelines. Content varies by publication. For example, Science (journal) "now requests" that, in general, authors place the bulk of their description of materials and methods online as supplementary materials, providing only as much methods description in the print manuscript as is necessary to follow the logic of the text." Nimur (talk) 02:36, 12 February 2015 (UTC)

Yes, this is what counts. Whether for publication or just a student paper, the advising faculty member should also be consulted. SemanticMantis (talk) 14:04, 12 February 2015 (UTC)

February 12

What are stem cells?

I know that stem cells are the basic building blocks of human development, are sometimes called “magic seeds.” But I want to submit a detailed paper on this topic. I am searching for the credible sources of information to gather detailed information. I collected some study materials from available academic reference. But I want more. Please provide detailed authentic information. — Preceding unsigned comment added by Mauriciogordon847 (talk • contribs) 06:02, 12 February 2015 (UTC)

Although Misplaced Pages itself should not be considered a reliable source, the 'References' and 'External links' sections of the Stem cell article might be useful for finding sources, and our article does "provide detailed authentic information".  —71.20.250.51 (talk) 06:24, 12 February 2015 (UTC)

If you eat fresh veggies, you eat stem cells all the time, e.g. apical meristem. Tasty! SemanticMantis (talk) 14:01, 12 February 2015 (UTC)

A stem cell is just a cell that can go through Cellular_differentiation to make other forms of tissue. SemanticMantis (talk) 14:03, 12 February 2015 (UTC)

Faraday cage and holes in one dimension

In a Faraday cage if the holes are smaller than the wavelength it will block it. What if the holes are smaller only in one dimension? e.g. long wires near each other, but no cross wires so the gaps are longer than the wavelength, but narrower than it. Will that block just as well as holes in two dimensions? Or somewhat worse? Ariel. (talk) 09:29, 12 February 2015 (UTC)

So you're asking if an arrangement like this: ========= will block the same wavelengths as this ######, assuming all gaps are equal sized? I don't know, but it's an interesting question and I just wanted to clarify :) SemanticMantis (talk) 14:13, 12 February 2015 (UTC)

The blocking is never perfect. That arrangement won't block the signals quite as well as small round holes, but it will still do a very good job of blocking if the gaps are thin enough. Looie496 (talk) 15:27, 12 February 2015 (UTC)

I'm not sure you'll get a Faraday cage effect if a closed circuit is not made. For the effect to work, you need to induce current loops in the cage, and the current needs a closed path to flow.

There are other means by which a metal grate can interfere with electromagnetic radiation, so Looie496 is correct that some signal will be blocked.

We discussed the details of Faraday cages a few weeks ago, and last time I ended up referring to Griffiths Introduction to Electromagnetism... so again, referring to theory from Chapter 2.5, to satisfy a condition that ensures ${\displaystyle {\vec {E}}=0}$, you need to ensure a closed path exists. If there is no closed path, there is no Faraday cage effect. Any other signal attenuation you observe is caused by something else - most probably, dielectric heating, which is not very effective signal attenuation mechanism in a metal conductor!

So, if the size of the gaps is sufficiently large that the impedance of the conductor attenuates any induced current at the frequency of the incoming wave, then the holes are "too big." The conceptual idea is that a path can be electrically short or electrically open for a specific frequency, and this response is governed by the material properties and the geometry. This is a really complicated geometry, and I don't think the signal behavior can be usefully solved analytically. At best, we could assume an "infinite sheet" of this material with a repeating geometry and try to solve for an incoming plane-wave. In practice, we would need an experimental setup or a rigorous computer simulation.

I think the only way to be sure is to test the theory by experiment! Nimur (talk) 16:46, 12 February 2015 (UTC)

I thought we were talking about something akin to a stack of looped wires, separated by small gaps (my crude diagram would just be one side then, and ignores whatever we do for the floor and ceiling). Each wire ring is a closed loop, but there's no cross hatching like you see in traditional mesh cages. So many separate loops are formed, if not one continuous circuit, and that should be enough to stop most/some of the voltage drop, down to some wavelength, right? SemanticMantis (talk) 21:23, 12 February 2015 (UTC)

Yes. Or even if the individual wires are connected together in one or two places, but not in the direction the EMF is coming from. Ariel. (talk) 23:57, 12 February 2015 (UTC)

I don't think closed loops are necessary. In order to block EM radiation, a Faraday cage or polarizer has to react within a time comparable to the wavelength divided by c, which means that electrical connectivity on scales significantly larger than the wavelength can't matter. Polarizers don't have closed wire loops at a scale comparable to the wavelength, yet they work. A Faraday cage with no electrical connection between the horizontal and vertical wires is equivalent to two polarizers offset by 90°, so it will work too. -- BenRG (talk) 00:23, 13 February 2015 (UTC)

An electromagnetic wave exhibiting linear polarization which has a direction matching the direction of the wires might be able to slip through. StuRat (talk) 16:01, 12 February 2015 (UTC)

Can't polarization always be separated into two vectors? So if you are correct wouldn't this mean that with random polarization half the energy would be able to slip in? Ariel. (talk) 00:00, 13 February 2015 (UTC)

Your cage of parallel wires is a polarizer. I think it's as simple as that. Re StuRat's answer, note that (quoting the article) "the notion that waves 'slip through' the gaps between the wires is wrong." -- BenRG (talk) 00:08, 13 February 2015 (UTC)

Testosterone and the voice

I heard a transgender man on the radio this morning, speaking about the impact of taking testosterone. The interviewee had quite a deep voice. It made me wonder. If a woman started taking testosterone, their voice deepened, and then they stopped taking the hormone, would their voice return to its previous pitch? --Dweller (talk) 09:56, 12 February 2015 (UTC)

Our Castration article says in the "Medical consequences" section: "Castrations after the onset of puberty... The voice does not change." Working on the principle that a female ceasing to take testosterone supplements has the same effects as castration in a normal man. Alansplodge (talk) 11:35, 12 February 2015 (UTC)

Thanks. I had a look around the vocal chords article and some others and it led me to an understanding that the voice change is prompted by growth of the chords, which I suppose wouldn't reverse itself just because the hormone that prompted it had stopped. --Dweller (talk) 11:38, 12 February 2015 (UTC)

That's right, here is a source that directly addresses testosterone taken by women: "If a woman wants to become a man, the use of male hormones will permanently deepen the pitch of the voice, because the vocal folds become thicker" (Voice Work: Art and Science in Changing Voices by Christina Shewell, John Wiley & Sons, 2013, p. 556 ). - Lindert (talk) 12:03, 12 February 2015 (UTC)

The Keen senses of the Gray Wolf, Jaguar/Panther and Puma

On a scale from 1 to 10, how keen are these three animal's senses relative to the rest of the animal Kingdom?

I'm well aware that these animals would score very high, but how high exactly? Personally, I would think that some of their senses are almost unmatched, such as the wolf's sense of smell.

1) Sense of Sight 
2) Sense of Sight in the dark 
3) Sense of Hearing 
4) Sense of Smell 

If you have first-hand knowledge or good sources to back up your opinions, then all the better. ;) 

2A02:FE0:C711:5C41:54B6:6EEA:430A:1573 (talk) 13:07, 12 February 2015 (UTC)

I doubt a wolf can beat moths on sense of smell. Some moths can detect a single molecule of sex pheromone: Manduca sexta's abilities are described here . SemanticMantis (talk) 13:57, 12 February 2015 (UTC)

However, I suspect that moth is very much tuned to smelling that particular molecule, at the cost of not smelling other molecules nearly as well. I'd go with size of the nose as being a good indicator of sense of smell. The longer the nose, the more room for olfactory receptors. Now some noses might not be 100% packed with receptors, or may not have the brain processing to use that info, but still it's hard to see how a moth, with so much smaller of a sensing area (the antennae, I believe, in their case) could compete on sense of smell with a wolf overall. StuRat (talk) 15:24, 12 February 2015 (UTC)

More generally, ranking things on a scale of 1-10 isn't a very scientific approach. For instance, suppose a bat can hear much higher frequencies than a wolf. But suppose a wolf can detect sounds at a much lower decibel level. Which one gets a higher score? it's all very subjective at that point. Similar arguments go for sight. No wolf will ever see what a mantis shrimp can see (broad spectrum, polarization, more cones, etc.), but a wolf probably has better visual acuity at a 10 m range. So the more scientific thing is to look for quantifications of these animals' sensory abilities. Along that line, here's an article that discusses the retina of dogs and wolves, and draws some conclusions about vision .SemanticMantis (talk) 15:07, 12 February 2015 (UTC)

I guess I can see your point, even though I was thinking within their domain/habitat. You mention shrimp, and of course in a watery world an aquatic creature will have senses better suited to an aquatic life than the wolf or a feline cat, and vice versa.

It is also easier to comprehend how most other mammals and many vertebrates (such as the animals I mentioned) sense the world around them than how many invertebrates and non-mammals do (like the ones you mentioned; moths and shrimps), since they are so vastly different. Saying that probably only strengthens your argument that it is often hard to compare. I accept that.

Thanks for links. I'll take a look at them. 2A02:FE0:C711:5C41:54B6:6EEA:430A:1573 (talk) 15:29, 12 February 2015 (UTC)

I'd suspect that exclusively nocturnal animals with big eyes, like the aye-aye, would have better night vision. Of course, if you count echolocation, then bats can "see" in absolute darkness (aye-ayes seem to use echolocation, too). I also suspect that in animals that use echolocation, their brain combines inputs from their eyes and ears to form a single image, so hearing and vision are really one in the same for them. StuRat (talk) 15:35, 12 February 2015 (UTC)

Sure, it will be easier to compare if we restrict to terrestrial vertebrates. This paper says that the eagle Aquila audax has "acuity is between 132 and 143 c/deg and with decreasing luminance acuity declines sharply." . That's the highest number I can find at a glance, will be interested to see if anything else does better in terms of c/deg (the cycles per degree measure of spatial acuity is described with good illustrations here ). This (rather odd slide show) gives humans at 60 c/deg, and a cat at 5 c/deg. I haven't yet found a reference for wolf vision in c/deg. SemanticMantis (talk) 16:02, 12 February 2015 (UTC)

Beyond moths, bears and African elephants are said to have great sense of smell in some fashion (these aren't great sources particularly the bear ones, I'm presenting them only to make further research in to the claims easier). Nil Einne (talk) 17:37, 12 February 2015 (UTC)

Sports science - runners' flexibility test

A few years ago I watched Eddie Izzard's program Eddie Iz Running, in which he ran a succession of marathon distances almost every day. Before this undertaking, he was subjected to some fitness tests by sports scientists (I think from Loughborough University). One of the tests was for his flexibility and balance, I think. If I recall it correctly, it worked like this: the subject stood on one leg, and touched the big toe of his other foot to the floor at various points of a notional clockface around him (without overbalancing). It seems like the "fitter" person could achieve a greater radius, and presumably it highlighted angles at which the subject was weaker or less flexible. I assume this is a standard test that's well documented in the sports science literature. What is the name of this test, and where can I read more about it? Thanks. 81.174.196.2 (talk) 16:45, 12 February 2015 (UTC)

I found Five Key Biomechanical Tests, but it doesn't include the one that you describe. The search continues.... Alansplodge (talk) 18:05, 12 February 2015 (UTC)

Metric Expansion of Space Article Removed by IP

Hi Folks,

I wanted to refer to an article called Metric Expansion of Space which I had read before, but I found that it was basically removed by an unidentified editer last month (Metric expansion of space).

I felt that since the content of this article is the valid subject of a hot debate, it shouldn't simply be excised at the will of an anonymous person. Perhaps the science / physics / cosmology expert volunteers out there could make pages that clarify the ideas and the nature of the debate about the ideas for the rest of us?

Thanks,

E.S. — Preceding unsigned comment added by 146.23.3.250 (talk) 19:32, 12 February 2015 (UTC)

What goes in the article can be discussed on the article's talk page, but the question of the metric expansion of space being science or nonsense is appropriate here. I thought that the metric expansion of space was an integral part of modern cosmology, but the IP editor removed most of the content calling it "pseudoscientific garbage:". Perhaps someone who has studied cosmology recently could take a look and see if the previous content of the article was supported by reliable sources or if the version of expansion there was pseudoscience as the IP redactor stated. Edison (talk) 20:03, 12 February 2015 (UTC)

The trouble with "metric expansion of space" is that it has caught on like a catch-phrase. "Metric" is an adjective and it has a specific meaning in mathematics and cosmological physics. "Expansion" of the universe refers to Hubble expansion. If you study cosmology in great depth, you can spend tons of time modeling that expansion and adapting the model to fit with our knowledge of gravity, relativity, conservation of energy, and so on - or to fit specific observational data to match a particular theoretical model. It has been my experience, though, that if you fixate on this buzz-word-esque phrase, you'll end up in pop-sci territory, rather than real science. That's not quite the same as "pseudoscience" - but if you want real science, here's a much better place to start: the NASA/IPAC Extragalactic Database's reading list, maintained by scientists at Jet Propulsion Laboratory (California Institute of Technology).

Those books are hard to read. I've only got a couple of them; and they are hard to read. But they are real science about cosmology, written for a scientific audience.

Nimur (talk) 20:21, 12 February 2015 (UTC)

The article should have some other name, such as "expansion of the universe" or "cosmological expansion" or "Hubble expansion". "Expansion of space" doesn't make sense in general relativity; there's no continuity equation for space that would let you say that there's new space appearing in some spacetime location. But renaming the article would probably involve endless arguments on the talk page, and I don't have the stomach for that. -- BenRG (talk) 21:10, 12 February 2015 (UTC)

The versions by the IP editor are nonsense. The versions they're trying to delete are fine, though not great. -- BenRG (talk) 21:10, 12 February 2015 (UTC)

It's probably the same editor that has been active at Ultimate fate of the universe with similar edits. Sjö (talk) 20:38, 12 February 2015 (UTC)

You can cite a particular timestamped version of a Misplaced Pages article to avoid problems like this. Click the history tab then click on any article version to get a permanent link to it, or click "permanent link" under "tools" in the sidebar to get the most recent version. -- BenRG (talk) 21:10, 12 February 2015 (UTC)

The deletion of the large amounts of material from the article by the IP is an example of vandalism. Each of the deletions is reverted. My advice to the original poster would be to create a registered account and use the watchlist feature to look for changes to the article, and revert the vandalism. One of the advantages of creating an account is the ability to create a watchlist, which has various uses including detecting vandalism to particular articles. Robert McClenon (talk) 23:15, 13 February 2015 (UTC)

Another way to deal with repeated vandalism of an article by IP addresses is semi-protection. A registered editor can request semi-protection of an article, which prevents edits by IP addresses. (That is yet another reason to create an account, to avoid being locked out by semi-protection.) Robert McClenon (talk) 23:17, 13 February 2015 (UTC)

February 13

Shrinking atom

I was briefly reading some arguments as to why an atom cannot be shrinking. But the most common one: electrons are point particles seems to be the most compelling evidence that atoms are shrinking. The subatomic particles are not shrinking as they can't since they are in fact true point particles. So what is shrinking is the distance among the various subatomic point particles. Since they are infinitely small they should be able to get infinitely close without ever touching. Right?73.160.39.193 (talk) 04:43, 13 February 2015 (UTC)

They aren't really particles at all, at least most of the time, when they behave more as wave probability functions. That is, they have no definite position. In the case of a black hole's gravitational singularity, the atoms do theoretically shrink into an infinitely small space (all of the atoms shrink into the same infinitely small point). StuRat (talk) 05:57, 13 February 2015 (UTC)

I don't see how what you say relates to my question.2601:C:3600:46B:5D02:835C:3D28:D9CE (talk) 06:57, 13 February 2015 (UTC)

We don't know what you have been reading, but you might like to try our articles on Atomic structure, Pauli exclusion principle and Atomic orbital, all of which suggest that the answer to your question is "wrong". I wonder if you are thinking of "metric" in the sense of atomic distances and thinking that this might be shrinking? The word "metric" in the confusing article title Metric expansion of space refers to the Friedmann–Lemaître–Robertson–Walker metric. Dbfirs 07:42, 13 February 2015 (UTC)

It might help in answering your question if you could explain why you think that atoms can/should shrink in the first place. The size of a hydrogen atom is basically set by the uncertainty principle, the electron mass, and the strength of the electromagnetic interaction. The first of those is too fundamental to change. The variation of the other two over the last few billion years is known to be small and is consistent with zero (see Fine-structure constant#Past rate of change, though it seems to imply there's convincing evidence for a nonzero variation, which I think is not the case). -- BenRG (talk) 10:03, 13 February 2015 (UTC)

• I suspect the OP is referring to the "alternate" theory to the big bang, that space is not expanding, but that matter is shrinking. This has been discussed before in the archives. μηδείς (talk) 20:54, 13 February 2015 (UTC)

pulmonary function test

where can i find information on this test and the application of its steps. — Preceding unsigned comment added by 71.46.193.85 (talk) 04:43, 13 February 2015 (UTC)

Do you mean the test where you blow into a tube and try to get the balls to rise as far as possible ? Or do you mean the test where they measure blood oxygen levels while the subject exercises ? Or some other test ? StuRat (talk) 05:59, 13 February 2015 (UTC)

See:here where the different tests are explained. Richerman (talk) 14:34, 13 February 2015 (UTC)

A quantum leap (jump) in the state of quantum equilibrium (balance) of the Law of conservation of energy

1) Did a quantum leap (jump) been in the state of quantum equilibrium (balance) of the Law of conservation of energy, that is be, could be the acceleration of quantum doing a quantum work in the state of quantum equilibrium (balance) of the Law of conservation of energy?--83.237.222.238 (talk) 10:25, 13 February 2015 (UTC)

2) May be quantum physics is been a special particular case of nuclear physics?--83.237.223.234 (talk) 11:18, 13 February 2015 (UTC)

Is been you Alex Sazonov? Dbfirs 12:34, 13 February 2015 (UTC)

I'm using perfect.--83.237.196.190 (talk) 13:30, 13 February 2015 (UTC)

Stappers will get you. Or be you Slandeutch? {The poster formerly known as 87.81.230.105} 212.95.237.92 (talk) 14:31, 13 February 2015 (UTC)

3) If in nuclear physics a work of acceleration of electron is always creating the output of energy, why did in quantum physics a work of acceleration of quantum did not creating the output of energy, is it be because the same and one electron been in a different physical state of the environment?--83.237.214.35 (talk) 14:16, 13 February 2015 (UTC)

2) Nuclear physics is defined in terms of the topic of study. Quantum mechanics is defined by the scale of the subject, and also by the type of math used. Sometimes, people use QM to study nuclear physics, sometimes they don't. From the first article: "A heavy nucleus can contain hundreds of nucleons which means that with some approximation it can be treated as a classical system, rather than a quantum-mechanical one." SemanticMantis (talk) 14:19, 13 February 2015 (UTC)

Thanks! I believe, that nuclear physics is been the physics of the ideal case – physics of ideal model, but quantum physics is not been same.--83.237.211.80 (talk) 14:34, 13 February 2015 (UTC)

Self-esteem and its relationship with narcissism.

Do people with high self-esteem tend to develop narcissism later in life, as Penn & Teller claimed in 2010? Thanks in advance. --Ann (talk) 16:57, 13 February 2015 (UTC)

I tend to think of self-esteem as relating more to superego ("I'm a good person !") and confidence ("I can accomplish anything !") and narcissism more to the ego ("Everybody wishes they were me !") and superficial qualities ("I am the prettiest/handsomest person and I have the most fashionable clothes, car, and house !"). So, I don't think they are directly related. StuRat (talk)

Egocentrism be better than a guilt complex in front of everyone! In my understanding, in christened Christians had been always living the Christian God, but not Proud - Satan, and even more so that the Lord God did not had the Sin in Self - pride and narcissism.--83.237.244.154 (talk) 18:16, 13 February 2015 (UTC)

Hi again, Alex. Is Moscow cold at this time of year? Are you using Google to translate from Russian? Dbfirs 19:20, 13 February 2015 (UTC)

Now-now, you don't have to get personal with the poster. It should be sufficient to ask, "What the bloody L are you talking about?" ←Baseball Bugs carrots→ 01:16, 14 February 2015 (UTC)

Even if Jesus Christ is not be the Lord God, he also had the Christian Christening!--85.141.239.49 (talk) 03:59, 14 February 2015 (UTC)

Edit: I should mention that I am primarily interested in scientific data that proves or disproves the aforesaid claim. Nonetheless I thank both of you for your replies. --Ann (talk) 18:40, 13 February 2015 (UTC)

I doubt if you'll have much luck with that, since personality traits are really just matters of opinion. There could be a study based on surveys, but that's just aggregated opinions. StuRat (talk) 19:57, 13 February 2015 (UTC)

That having an ego means one thinks "Everybody wishes they were me !" is one such opinion. We all have an ego, but most of us don't think like that, Stu. Quote from Id, ego and super-ego#Ego: The ego is the organized part of the personality structure that includes defensive, perceptual, intellectual-cognitive, and executive functions. Conscious awareness resides in the ego, although not all of the operations of the ego are conscious. -- Jack of Oz 22:00, 13 February 2015 (UTC)

Well, I wanted to give a quick summary of the differences without explaining all the various conceptions of ego from various philosophers, and without them having to read it in all of our related articles, either. StuRat (talk) 23:37, 13 February 2015 (UTC)

Maybe a noble aim, except your quick summary of the ego is nothing like its accepted meaning. What you gave is closer to an example of narcissism than to the ego. -- Jack of Oz 04:16, 14 February 2015 (UTC)

The article Narcissistic personality disorder has the following quote: "A nationwide study in the United States found that 7.7 percent of men and 4.8 percent of women could be diagnosed with narcissistic personality disorder (Stinson et al., 2008). These data also suggest that narcissistic personality disorder is more prevalent among younger adults, possibly supporting the impression that narcissistic personality disorder is on the rise as a result of social and economic conditions that support more extreme versions of self-focused individualism (Bender, 2012)." Its not clear from this whether "self-focused individualism" entails higher self-esteem, but it's possible. The reference link for this is gone, but Donna S Bender published this article in 2012 on the issues. --Modocc (talk) 22:53, 13 February 2015 (UTC)

Is there any reliable evidence of different CD players differing in audio quality?

Of course, I mean stand-alone players. And by "evidence", I mean double-blind trials. I am aware that some audiophiles disparage double-blind studies, but I'm not sure why. If there is evidence of difference, what factors matter?--Leon (talk) 20:09, 13 February 2015 (UTC)

CD systems and stereos may intentionally apply audio equalization, according to the preferences of the manufacturer. This means that the audio signal that goes out of the box is not intended to be a waveform-accurate, perfect recreation of the original waveform that was losslessly recorded in the digital medium.

Depending on the nature of that type of post-processing, it's completely plausible that the sound quality can differ between makes and models.

For example, here's an application note (colored by a little marketing-ese) on the use of Analog Devices Blackfin DSPs to post-process audio signals in a consumer-grade stereo system. The entire purpose of that DSP is to intentionally distort the waveform, not to perfectly recreate it. The objective is to improve quality, but whether that goal is accomplished is subjective. Nimur (talk) 20:27, 13 February 2015 (UTC)

By "stand-alone players" you are presumably excluding the speakers, as obviously those will vary in quality from device to device. StuRat (talk) 21:22, 13 February 2015 (UTC)

Yes apparently that is obvious to the tiniest mind. The well phrased question did not leave that open to doubt. As to the question, there are different D to A strategies (I doubt these are audible), and then there are different error correction strategies (could easily be audible), and then there are different manipulations applied to the analog signal. Different CD players will have different amounts and spectra of crosstalk and noise in their analog stages. So i'd say yes, it is quite likely that some people could reliably identify a particular CD player in an ABX test, on some CDs.

There is no doubt that not all modern audio systems are perfect...and perhaps some audiophiles can tell the difference. But there are two things at issue here - most people like the audio to be deliberately tweaked compared to 'reality' so very often, it's a matter of personal preference rather than some measurable "quality" metric. The deeper problem is that audophiles are a sad, sad bunch of people. They used to have a hobby like those of many geeks where they could become totally immersed in a deep technical subject and become experts - then they could argue with each other about the merits of this amplifier with that turntable with this special zirconium-tipped stylus or whatever. They had a GREAT hobby. Then along came CD's and digital audio and sound reproduction became (by far) better than the human ear can possibly detect. Overnight, their expertise is blown away. A $100 sound system performs pretty much as well as at $10,000 sound system...and everything they knew about analog audio became irrelevent.

Some of those people turned to other subjects and became computer geeks or video geeks or car geeks. But a few persist in their claims to be able to detect the most subtle imaginable differences, then claiming this or that cause. They dislike double-blind tests simply because they conclusively prove that all of these people are talking utter, utter bullshit. They don't want to hear that because they've invested so much of their very souls into this subject.

If you ever doubt this, just take a look at this $10,000 ethernet cable...which any non-audiophile will tell you will perform PRECISELY identically to these cables which cost $12 for a pack of 5. This is just insanity. Double-blind listening tests would demolish this claim in a heartbeat.

Now, the unfortunate part about this is that it is remotely possible that the different quality of A-to-D converters might make a difference in the sound quality of one CD player versus another. But because of this audiophile madness, you simply cannot trust a single word they say...anyone who will claim to hear the difference in sound quality between a purely digital signal streamed over a $10,000 ethernet cable versus a $3 cable simply cannot be trusted to tell you the difference between a $20 and a $30 CD player. Even if there is a difference - the choice between one and the other is likely to be hotly debated and largely a matter of personal preference anyway.

SteveBaker (talk) 00:35, 14 February 2015 (UTC)

Does anyone know if there a simpler explanation?

My cat went meow when she saw this clip from Soyuz rendezvous and docking explained . Were a cosmonaut launches a giraffe... There appears to be a 'I love Russia' ideogram where not even a made in china label ought to be – but it is out of focus by the time it comes into view so not easy to say. Is this supposed to be a subtle subliminal message due to its juxtaposition or propriety gone wrong? Every gram costs money to send into obit.--Aspro (talk) 21:40, 13 February 2015 (UTC)

I don't know what, but it might be a label identifying whatever lies inside the giraffe that the fabric is protecting. Or maybe weight is not a premium because it's a demo shot from within a plane in freefall? Or, as you suggest, it's just simply a fun propaganda toy, and I like this explanation the best, :-) BTW, thus far, my searches for images of the label or ideogram hasn't turned up anything like it. -Modocc (talk) 23:04, 13 February 2015 (UTC)

Isn't it simply the Ty Inc. logo? That Beanie Baby appears to be called "Giraffiti", which was taken into space on Soyuz TMA-13M (ref) -- Finlay McWalterᚠTalk 23:40, 13 February 2015 (UTC)

Was there an animal sound on the soundtrack? That's more likely to make a cat react than a random image. ←Baseball Bugs carrots→ 01:12, 14 February 2015 (UTC)

Funny now that I play the clip again that the label appears much clearer than earlier when it was fuzzy. Does youtube radically change/adjust the resolution of the video it streams? Or am I just imagining things and I am preconditioned now to recognize what is obviously the Ty label? On second thought, the variance could very well be due to my macular degeneration. --Modocc (talk) 04:46, 14 February 2015 (UTC)

It take it you don't live in my part of Europe, where we feel that we have lost the Cold War, since all the rich Russian oligarchs are over here buying up real-estate and everything else – like money is going out of fashion. This is an example of such an ideogram: . Bears a remarkable resemblance to that covering the giraffe's κωλοτρυπίδα don't you think? --Aspro (talk) 14:19, 14 February 2015 (UTC)

February 14

MMR Vaccine side effects

What are the potential adverse effects of the MMR, and do they differ in an adult who has received 1 dose previously, from someone who has never received 1 dose? — Preceding unsigned comment added by 198.255.253.60 (talk) 00:44, 14 February 2015 (UTC)

Assuming you've read MMR vaccine, talk to your healthcare provider, we cannot provide medical advice. μηδείς (talk) 00:48, 14 February 2015 (UTC)

What does N/A stands for?

I read about the PR interval in the table, and there is N/A in this squareץ What does it stands for?5.28.165.129 (talk) 02:09, 14 February 2015 (UTC)

It would be better to have a link to the page you are referring to, but it sounds like n/a. ―Mandruss ☎ 02:13, 14 February 2015 (UTC)

Typically "not applicable". ←Baseball Bugs carrots→ 02:31, 14 February 2015 (UTC)

Please, look at the page here here is the original text (n/a)5.28.165.129 (talk) 03:35, 14 February 2015 (UTC)

• Edited the above to make it a link. --70.49.169.244 (talk) 10:32, 14 February 2015 (UTC)

Yes, that looks like n/a. <--- That is a link, click it. ―Mandruss ☎ 03:38, 14 February 2015 (UTC)

So, since the P wave was "absent or not related" in this idioventricular rhythm, there is no PR interval and therefore it is "not applicable". In another case, N/A might mean "not available". --70.49.169.244 (talk) 10:32, 14 February 2015 (UTC)

kink

What is the thing kink in the thermometer ? I have read this in one encyclopedia.I thought this one is the structure in mercury thermometer.Arvind asia (talk) 06:40, 14 February 2015 (UTC)

What are you talking about? Can you find an example on Google Images and link it here? ←Baseball Bugs carrots→ 06:47, 14 February 2015 (UTC)

Here is a picture of a mercury thermometer. Where are you seeing a "kink" in it? ←Baseball Bugs carrots→ 07:02, 14 February 2015 (UTC)

That isn't a medical thermometer. --Modocc (talk) 07:08, 14 February 2015 (UTC)

The OP didn't say anything about a medical thermometer. ←Baseball Bugs carrots→ 07:42, 14 February 2015 (UTC)

A Google search on kink in the thermometer gives results explaining that the "kink" is a constriction near the bulb that prevents the mercury from falling after its removal. --Modocc (talk) 07:08, 14 February 2015 (UTC)

That would make sense, if it's what the OP is asking about. ←Baseball Bugs carrots→ 07:42, 14 February 2015 (UTC)

I think it is. The medical thermometer article explains it (under "liquid-filled") but rather briefly. The point is that you want to measure the temperature at a particular place on a person's body (mouth, rectum, armpit, etc.) but it isn't convenient to read the thermometer while it's inserted there. And as soon as you pull it out, the temperature drops, so after inserting the thermometer you would have to read it right away to get a valid reading. Instead the thermometer is made with a constriction—a kink—between the bulb and the tube. Then when the temperature of the bulb drops, the mercury (or other liquid) will not return to the bulb, the reading stays the same, and you can read it at your convenience. After doing that, you swing the thermometer with the bulb outwards and this forces the mercury back down through the construction (this works particularly well with mercury since it's so dense). So the thermometer is ready to use again once it's been cleaned.

Meteorologists used to use the same kind of thermometer to determine the high temperature each day. I presume they now determine it based on records from some sort of digital thermometer. --70.49.169.244 (talk) 10:46, 14 February 2015 (UTC)

What is been the cause of local fighting in the East of the Republic Ukraine?

1) Did the military local conflict in the East of Republic Ukraine had religious reasons, if as in Russia Imperia the Cathedra of Moscow Patriarchate in Russia had ensures the stability of the whole Orthodoxy, but because the split of the Cathedra of Moscow Patriarchate in Russia not had, and now could not had been at all, what is been the cause of local fighting in the East of the Republic Ukraine?

2) Did the local military conflict in the East of the Republic Ukraine been same similarity with the local military conflicts in the Republic of Moldova? — Preceding unsigned comment added by 83.237.221.6 (talk) 06:50, 14 February 2015 (UTC) --83.237.221.6 (talk) 06:50, 14 February 2015 (UTC)

It's not about religion, it's about Russian expansionism. They already took Crimea, and they want as much of the rest of Ukraine as they can get. ←Baseball Bugs carrots→ 06:54, 14 February 2015 (UTC)

I think that the West of the Republic Ukraine is been a passive participant in the local military conflict of the East of the Republic Ukraine.--83.237.193.210 (talk) 07:14, 14 February 2015 (UTC)

Well, the western part of the country was instrumental in ousting the Putin buddy who was their president, and that's what triggered Russia's aggression into Ukraine. ←Baseball Bugs carrots→ 07:43, 14 February 2015 (UTC)

WP:NOTAFORUM. There are plenty of sources which support your interpretation of events here, but at most you should be citing them, or discussing well-established facts, historical or otherwise. But this is not the appropriate place to be carrying on discussions concerning our personal speculation about the motives of the Russian government or the absolute proximal causes of the conflict. Snow talk 10:43, 14 February 2015 (UTC)

Who are you talking to? And besides that, what is this doing on the Science page? ←Baseball Bugs carrots→ 10:47, 14 February 2015 (UTC)

I suppose I was talking to both of you, but I can't expect the IP to have the experience to understand the distinction between what kind of discussions we are meant to be having here and how they differ from an open forum. But yes, you are correct -- clearly this the wrong desk for this question from a topical standpoint. Snow talk 10:59, 14 February 2015 (UTC)

I seem that this page is not a public forum for a differents discussion, but the someway or anyway, the local military conflict is benign between of the East of the Republic Ukraine. Thanks!--83.237.240.49 (talk) 12:04, 14 February 2015 (UTC)

Well, I don't understand what you're saying. Maybe someone will, and can help you better. ←Baseball Bugs carrots→ 13:00, 14 February 2015 (UTC)

I recommend you go to List_of_wars_involving_Ukraine#Since_1991, which has links to the ongoing crises of the last year or so. ←Baseball Bugs carrots→ 13:03, 14 February 2015 (UTC)

Not only is this not a public forum for discussion, it's also the science reference desk. The could be questions relating to the conflict which would fit here. But neither of the two above come close. Nil Einne (talk) 13:01, 14 February 2015 (UTC)

Friction force must be velocity dependent

I'm pretty sure that the friction force must vanish as the relative velocity of the two objects in contact approaches zero. But the equation ${\displaystyle F=\mu F_{N}}$ doesn't seem to be able to take this into account.

The naive ${\displaystyle m{\frac {d^{2}x}{dt^{2}}}=-\mu F_{N}}$ would only lead to position and velocity escaping without bound to negative infinity, so I obviously need a better equation of motion, e.g. for modeling when a shuffleboard piece comes to rest due to friction alone.--Jasper Deng (talk) 07:35, 14 February 2015 (UTC)

Your assumption is wrong. Gently push on a book on your desk. Does it move? Its velocity is 0 with respect to the desk, yet friction is non-zero, because the book doesn't move. --98.232.12.250 (talk) 08:06, 14 February 2015 (UTC)

That's not the point. This is assuming that there is no external force. An object in motion without any force but friction and the normal force still experiences a nonzero friction force, and will eventually come to a stop (think an ice hockey puck on a large sheet of flat (real) ice). If the friction force were then still nonzero, then the object would accelerate. Absent any motive force to move an object, the friction force must be zero at rest, because there cannot be a net force in any direction.--Jasper Deng (talk) 08:14, 14 February 2015 (UTC)

The coefficient of static friction is not always exactly the same as the coefficient of sliding friction, but for most materials they are very close. There is one error in your equation: The friction force does not always attain its maximum value, so the correct version of your first equation is ${\displaystyle F}$_max${\displaystyle =\mu F_{N}}$, though the friction force will retain its maximum value whilst sliding continues.

You also seem to have a sign error not in your second equation but in your interpretation of it for sliding friction. The friction force always opposes relative motion. Dbfirs 08:21, 14 February 2015 (UTC)

If friction was proportional to relative speed, then objects would glide gently to rest like a well-driven car. If you observe carefully, they come to rest abruptly (as with harsh braking). Friction reduces to zero, of course, when there is no relative motion and no other force parallel to the surfaces. Dbfirs 08:25, 14 February 2015 (UTC)

Seems like the work-energy theorem is a more viable strategy for this kind of problem, since from what I can tell, there's a discontinuity between kinetic and static friction and I have no formula for the actual friction force (rather than its maximum).--Jasper Deng (talk) 08:31, 14 February 2015 (UTC)

Yes, work done by friction is a useful quantity to consider, but it uses the fact that sliding friction is constant at its maximum value. You can calculate static friction quite easily by considering other forces on the system in equilibrium, and remembering that friction cannot exceed its maximum value. Dbfirs 09:28, 14 February 2015 (UTC)

With a constant deceleration due to the friction, the finite distance traveled is v/a. -Modocc (talk) 08:44, 14 February 2015 (UTC)

Actually it would be v/(2a) using ${\displaystyle v^{2}=v_{0}^{2}+2a(x-x_{0})}$.--Jasper Deng (talk) 09:21, 14 February 2015 (UTC)

It's half as far (those 2s tend to sneak in there, yet it's still finite :-). I should have cracked open my forty year old physics book before I answered. --Modocc (talk) 09:37, 14 February 2015 (UTC)

Sorry, I believe that gravity is always determining the action of all the forces in nature of the planet Earth and also vectors of these forces, because in case of the absence of gravity the action of the forces is being disproportionate (mathematical dysfunction), that is, in this case the universal balance of the Law of conservation of energy did not observed in nature, besides that such physical-mathematical unit as mass never had inverse proportionate.--83.237.198.2 (talk) 08:58, 14 February 2015 (UTC)

Hi Alex, What on earth are you going on about? No, don't answer that question or people will really think you are a troll! Dbfirs 09:23, 14 February 2015 (UTC)

I’m sorry, the question being interesting, I’m still using translator, of course I’m not a troll.--83.237.198.2 (talk) 09:46, 14 February 2015 (UTC)

See for a model of the recovery of static friction. It's behind a paywall, but libraries do have copies . -Modocc (talk) 11:16, 14 February 2015 (UTC)

Writing research reports

When writing research reports is it wise to write any of the discussion, evaluation or conclusions before you have a full set of results? I've heard you can write introduction and methodology but nothing after results section. 194.66.246.19 (talk) 11:54, 14 February 2015 (UTC)

A research report is means to document and communicate research findings. If there are organization- or publication-defined guidelines that you are required to follow, follow them. Otherwise, you can do whatever you want. Of course, some ways of structuring a report are better than others at helping the reader understand the report's content. Typically reports in general will have an abstract that explains what the report is about and a very brief description of its findings. It's there to help the reader quickly decide whether they want to read the actual report. There may also be an executive summary for those who need to get the gist of it but have no time or need for all the gory details. Concise statements of important facts, conclusions, and implications are appropriate there. To help the reader understand its content, you usually begin a report with an introduction that explains what problem the it addresses, why the investigation was done, the methodology used, the major findings and their significance. You may also want to provide some background information (relevant definitions, facts already known, etc) to help non-specialists understand the main content of the report. You then go into the methodology & design of the study, with enough details to enable the reader to evaluate the soundness of the methodology and to try to replicate the study if they wanted to. You then present the data collected and how they were processed to yield relevant statistics and interpretations. At this point the reader has been exposed to the details of the study and its findings. You can have a discussion of the findings and their implications if you want to. You structure your report to help your reader understand its content. Whether a particular document structure makes sense should be evaluated against that goal. If you're not constrained by rules that others require you to follow, just do what you think makes sense. --98.114.146.37 (talk) 14:44, 14 February 2015 (UTC)

Testing a helmet by being driven over by a tank

Is that a meaningful method to test a helmet as Michael Schumacher did here Michael_Schumacher#Helmet? Tanks are neither too fast, and they distribute pretty well their weight. Add to this that the scenario is totally unrealistic. Noopolo (talk) 14:40, 14 February 2015 (UTC)

Which tank are we talking? They come in all sizes and weights. Sir William Matthew Flinders Petrie | 25 Shevat 5775 14:45, 14 February 2015 (UTC)

The article doesn't say, but any tank will distribute quite well its weight, this is the idea of having tracks.--Noopolo (talk) 15:43, 14 February 2015 (UTC)

black body radiation 86.190.50.197 (talk) 15:39, 14 February 2015 (UTC)

when planck was developing his theory, how did the researchers measure the temperature of the source and the intensity of the radiation ?

aurora borealis

I wondered why you left out the sound the Northern Lights makes. If conditions are right the Northern Lights can be heard by the naked ear. Sounds of the Northern Lights is now a science in its self. — Preceding unsigned comment added by 2601:6:E00:92C0:F0FD:CD00:80CD:824C (talk) 15:42, 14 February 2015 (UTC)

• Pages automatically checked for accidental language links
• Misplaced Pages resources for researchers
• Misplaced Pages help forums
• Misplaced Pages reference desk