If you bite your tongue or cheek with force, you get a painful area that feels "hard", as if the area swells or something like that. What generally causes this phenomenon (i.e. is it swelling, or something else?), and (if such a term exists) what's the official anatomical/physiological term for an area that's experiencing this phenomenon? Nyttend (talk) 03:23, 17 November 2013 (UTC)[reply]

When most parts of the body are subject to trauma (e.g. biting of the tongue, banging the head, trapping a finger) it is normal for two things to happen. Firstly the body has a reaction which involves extra blood being channeled to the injured area, this assists in bringing materials required to repair the area and the removal of any unwanted products of trauma. The other thing that occurs is bleeding within the soft tissue that is damaged. This causes discoloration, swelling and pain in variable amounts dependent on what and how badly the tissue is damaged. These two processes will cause the swelling you feel, the medical term for hardening of the tissue is induration. Richard Avery (talk) 07:49, 17 November 2013 (UTC)[reply]

Does there exist a design for an electric unicycle, where the rider is positioned at the centre of a wheel, rather than atop it; the engine contains no moving parts; and the unicycle is steered by shifting the centre of mass along the axis of rotation? Plasmic Physics (talk) 03:59, 17 November 2013 (UTC)[reply]

I believe you have a monowheel in mind. However, note that there must be moving parts: in your proposed design, even though the center of mass is kept steadily ahead to move it forward, it has to be moving in a circle relative to the outer wheel (as is the rider). (speculation:) Using a weight in this way depends on it being massive in relation to the rider; I suspect it works out to be inefficient to push a weight to where it will move the wheel by force of gravity rather than simply pushing the wheel with the same motor mechanism. Wnt (talk) 04:22, 17 November 2013 (UTC)[reply]

Yes, it is a monowheel I'm thinking of. Plasmic Physics (talk) 05:39, 17 November 2013 (UTC)[reply]

I suppose you could set up a mag-lev connection between the wheel and the compartment where the rider sits. They would still move relative to each other, but there would be no friction (other than air resistance), since the moving parts are not in contact with each other. The rider could then lean forward to move forward or lean backward to move backward. Leaning to the sides should help to steer. StuRat (talk) 05:15, 17 November 2013 (UTC)[reply]

Yes, it is a monowheel that functions on the principle of the linear motor. To ensure that the wheel spins instead of the rider, it could be solved by increasing the difference in the moment of inertia between the wheel and "hub". Plasmic Physics (talk) 05:39, 17 November 2013 (UTC)[reply]

I meant that last sentence as a question, not as statement. Plasmic Physics (talk) 07:52, 17 November 2013 (UTC)[reply]

Yes, the moment of inertia should effect which rotates faster. I also imagine that the battery, motor, etc., would be under the driver's seat, to bring the center of gravity down. This would help prevent him from turning upside down. At high acceleration, though, it might still be a problem. Driver rotation might also occur when braking or if the vehicle hits something. StuRat (talk) 08:41, 18 November 2013 (UTC)[reply]

What if the entire vehicle was structured as a gyroscope? Plasmic Physics (talk) 12:08, 18 November 2013 (UTC)[reply]

I made this circuit to light a couple of LEDs (in series) on my bike. The power comes from a bottle dynamo which I think is rated at 6 V and 3 W. My question is: does the light get ever brighter the faster I cycle or does something limit the output of the dynamo? The LEDs can actually handle at least an amp but I'm a pretty lazy cyclist so I'll never even approach that; I just wondered. If the rating is 3W, that must mean the limit for the dynamo is 500 mA; is that a point at which something inside the dynamo could start to melt? --78.148.107.181 (talk) 16:03, 17 November 2013 (UTC)[reply]

A bicycle dynamo is not, in fact, a dynamo, but a magneto (generator). However, although we have plenty of articles on magnetos, we don't have one which explains how they work. This paper describes the operation of an ignition magneto - a bicycle dynamo doesn't have the contact breaker or secondary winding, but it's more or less the same otherwise, and the Continental paper does imply that the output increases with speed. That being said, I assume that there will be a point where the rotor is continuously saturated and increasing the speed only increases the frequency. The best thing to do is probably just try it, and put in a voltage regulator if the output looks like it's getting too high. Tevildo (talk) 19:50, 17 November 2013 (UTC)[reply]

As speed is increased from zero, the generator voltage will increase proportionately, up to a certain point where the load (the lamps or LEDs) draws a current near the rated output. Beyond that point, two effects come into play that limit the current: a) magnetic saturation of the stator core (Tevildo was on the right track here, but it is the magnets that rotate on the shaft, the windings are on a stator - this avoids needing slip-rings) and, b) pole reluctance. Pole reluctance arises because at high currents the magnetic filed in the stator poles created by the load current opposes the magnet field as the rotor magnet poles rotate into mesh with the stator poles. This effectively lengthens the air gap between the rotor and stator, weakening the generated voltage. The limiting is not a hard or staright line limit - further increase in load or speed will increase the current to a certrain extent. 120.145.133.195 (talk) 00:45, 18 November 2013 (UTC)[reply]

So would it then be approaching an asymptotic limit? 24.23.196.85 (talk) 02:00, 18 November 2013 (UTC)[reply]

The electricity-producing thing on my old bike was called an 'alternator' when I bought it, so presumably it produces alternating current. To drive LEDs, I would consider adding add a rectifier chip and a capacitor to smooth the ripple, and would tip the bike and spin it to make sure it could not overdrive the LEDs and burn them out. Edison (talk) 01:28, 18 November 2013 (UTC)[reply]

All my fasting glucose tests taken at a medical lab (vein blood) show above 100 mg/dL. However home test (finger prick) results are always ~80 mg/dL, no fasting, before and 1.5 hours after a big meal. How can this be explained? Gil_mo (talk) 16:16, 17 November 2013 (UTC)[reply]

I'm afraid that because this bears on your personal medical issues, an answer would constitute medical advice, which we are not permitted to give. Looie496 (talk) 16:53, 17 November 2013 (UTC)[reply]

I'm asking this on a general note. Let me rephrase: what could be the explanation for such a discrepancy should it occur for anyone doing the test?Gil_mo (talk) 07:10, 18 November 2013 (UTC)[reply]

See Glucose meter, home tests measure whole blood glucose level, lab tests measure plasma glucose level which is generally 10% to 15% higher than the equivalent whole blood value. All the glucose is in the plasma, if you remove the blood cells, the volume decreases but the amount of glucose stays the same, so the amount of glucose per unit of volume rises. Ssscienccce (talk) 11:28, 18 November 2013 (UTC)[reply]

Obvious question, are the home testing strips expired? Have they been stored in an airtight container? Have they been stored in excess heat (like a hot car)? I know these can affect the accuracy. Also, many home testing units contain a little bottle of control solution (with a known glucose concentration) that you can test your strips against. --209.203.125.162 (talk) 18:55, 19 November 2013 (UTC)[reply]

magnification is independent in series or parallel circuit.true or false? — Preceding unsigned comment added by Mintoooo (talk • contribs) 17:51, 17 November 2013 (UTC)[reply]

The word "magnification" has no meaning for an electrical circuit. If you are going to ask "true or false", you need to use correct terminology. In this case, I can't even figure out what you are trying to ask. Looie496 (talk) 17:57, 17 November 2013 (UTC)[reply]

To paraphrase Chico Marx, then, the correct answer to the question is, "No." ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:52, 17 November 2013 (UTC)[reply]

I added a useful title. StuRat (talk) 06:03, 18 November 2013 (UTC) [reply]

We have some scant coverage at LC_circuit#Applications, which uses the "magnification" terminology, and mentions the tuning discussed above. SemanticMantis (talk) 18:10, 18 November 2013 (UTC)[reply]

Most likely because the term is most likely and commonly called resonance and specifically electrical resonance. --DHeyward (talk) 05:30, 19 November 2013 (UTC)[reply]

References: New Approach to the Digital Measurement of Magnification Factor

Marconi TF 1245 circuit magnification Q meter, the instrument identified by the first correct responder

(image) 84.209.89.214 (talk) 22:37, 19 November 2013 (UTC)[reply]

Although higher derivatives of the position are not discussed by the Newton while formulating “F = GMm/d^2” (where reduction in “d” is lopsided for the falling of small objects on earth) but verily the subtle nuances of such spawning can easily be perceived through arcane reasoning if imagined two identical planets of mammoth masses “M” separated by conspicuous on-center distance “d”. Since both masses "M" are under the influence of gravitational force "F" therefore reduction in “d” would be equal but abrupt on either side of point “c” lucidly if “c” is the mid point of “d" as both F = GM^2/d^2 and "g =GM/d^2" are time varying.

The simultaneous abruptness of such motion starts equally on either side of "c" right at the inception of "g" of each M which sent the aforementioned masses “M” swiftly into different higher types of motion such as gravitational jerk, jounce, crackle, pop, lock, drop etc. This means two objects that fall towards each other are under the influence of higher types of gravitational motion/ higher derivatives of position w.r.t time - Theoretically.162.157.235.1 (talk) 23:24, 17 November 2013 (UTC)EEK[reply]

Under Newtonian gravity, there are no higher derivatives of position due to gravity. The acceleration really is a=GM/d^2, and the third, fourth, fifth, etc. derivatives of position are all zero. --Bowlhover (talk) 02:16, 18 November 2013 (UTC)[reply]

Not correct in general. If d is not constant then a is not constant either, so higher derovatives of position such as da/dt are not zero. Only exception I can think of is a circular orbit when the magnitudes of d and a are constant (although even then they are not constant when considered as vectors). Gandalf61 (talk) 10:05, 18 November 2013 (UTC)[reply]

But this hold true only when the difference in two masses is extremely gigantic. For example it is said that both earth and the Newton's apple (smaller objects) accelerate toward each other gravitationally but apple looks a lot to the earth due to its greater acceleration as compared to the earth toward an apple which is so minuscule to be distinguished. Here in this case the on-center distance “d” reduces totally on one side of the mid point of “d” as earth remains at its position (almost) therefore a=GM/d^2 is noticeable but the picture is totally different according to the equation “F = GM^2/d^2” if both the masses are mammoth as illustrated where on-center distance “d” reduces equally on both sides of the mid point of “d” therefore aren’t the said two objects under the influence of type of gravitational motion which is greater than “a=g=GM/d^2”162.157.235.1 (talk) 04:45, 18 November 2013 (UTC)EEK[reply]

The force acting on each object is F=GM^2/d^2. Therefore, by F=Ma (the definition of force), a=GM^2/Md^2 = GM/d^2. Since the acceleration varies with position (and position with time), there will be higher derivatives w.r.t. time, but these just describe how the acceleration changes, it's not correct to say that jerk "prevails over" accelration, instead, each of jerk, acceleration, velocity etc are used to describe how the position of the masses changes. Acceleration just tends to be the most used representation, since higher derivatives tend to be less mathematically useful. Also, in the graviational case, aceleration can always be expressed purely as a function of position, with no initial condition needed for velocity, but higher deivatives will require at least such conditions to be calculated accurately. (da/dt = da/dx . dx/dt = v.da/dx = -2vGM/d^3 in the case where the velocity is parallel to the acceleration). 91.208.124.126 (talk) 09:38, 18 November 2013 (UTC)[reply]

Wouldn't the said both identical masses in scenario collided each other earlier than expected in acceleration?74.200.19.65 (talk) 11:20, 19 November 2013 (UTC)EEK[reply]

My mental image of the Korean War is that of soldiers spending months and months in snow-filled trenches, freezing off half their extremities as they wait for the weather to get warm enough for combat. The climate section of Geography of South Korea would seem to back up my idea, talking about "Winters are usually long, cold, and dry", but the specific data in Climate of Seoul sounds far warmer and more hospitable than my mental image or the picture created by the first article's climate section. What's going on? What's the true situation? Nyttend (talk) 02:35, 18 November 2013 (UTC)[reply]

Well, Seoul is close to the Yellow Sea, and being near a large body of water will tend to warm and moisten things up in winter, if the prevailing wind direction comes in off the water (unless the water freezes over, and I don't think it's far enough north for ocean water to freeze solid there). So, that's my guess as to why it might be warmer than the interior, in winter.

Also, during a war people (both soldiers and refugees) tend to be far more exposed to the environment. So, a temperature which is just fine if you are in a house becomes unbearably cold if you are in a flooded foxhole. StuRat (talk) 04:58, 18 November 2013 (UTC)[reply]

Finally, the cold weather was a major factor in the Battle of Chosin Reservoir, which may have been the images that you were thinking of. Not only is this in the far north of North Korea, close to the border with Manchuria, but the reservoir itself is over 1,200 metres (4,000 feet) above sea level and much of the fighting was on higher peaks and passes. The Environmentallapse rate allows you to calculate a reduction in ambient temperature of 6.49 °C per 1,000 metres of altitude, plus whatever windchill you get in a high mountain pass. Alansplodge (talk) 09:24, 18 November 2013 (UTC)[reply]

BTW, the figures in the climate table that you linked are certainly cold for a climate described as Humid subtropical. The average winter temperatures are lower than Copenhagen for instance. Alansplodge (talk) 11:43, 18 November 2013 (UTC)[reply]

Also, don't forget that the early '50s were at the very end of a short-term global colding trend (which started in the mid-'30s and was at its peak in 1944 -- that was the coldest year of the 20th century), so temperatures worldwide were lower than average. 24.23.196.85 (talk) 07:34, 19 November 2013 (UTC)[reply]

Following 2005 inorganic IUPAC additive nomenclature, is the following a correct name for [Be]=N[Be]N([Be]N=[Be])[Be]N=[Be]?

μ₃-nitrido-1:1':1"κ³N-tris(μ-nitrido-diberyllium)

Plasmic Physics (talk) 02:41, 18 November 2013 (UTC)[reply]

Wow. This is not my expertise, but there's some coverage of this at [1] but this is... remarkable. So you have a single nitrido (N) bridging three Be-N-Be units (the μ-nitrido-diberyllium). The κ³ indicates the N is linked three times from N (where else?). I suppose the 1:1':1" is a specification of where it links to. But I don't know if the IUPAC rules really require or allow that kind of precision about where a nitrogen is linked from when there's one atom, or so much detail about the three units it links to when it's just tris()... it all seems so absurd. Wnt (talk) 08:46, 18 November 2013 (UTC)[reply]

I'm also using the 2005 Red Book, but I was using IR 9.5.2.1, specifically comments surrounding example 8. Plasmic Physics (talk) 12:00, 18 November 2013 (UTC)[reply]

I have read the article "Heat transfer coefficient", only found fluid flowing over horizontal plates (not a plate). Can someone give me an equation on the case of one plate. Many thanks :) SongJie@NTU (talk) 14:23, 18 November 2013 (UTC)[reply]

If you're referring to Heat transfer coefficient#External flow, Horizontal plates, the equations seem to describe a single plate (in four different scenarios), in spite of the section title. If that doesn't meet your needs, could you be clearer about what your needs are? Looie496 (talk) 16:04, 18 November 2013 (UTC)[reply]

Is there a way to make adult stem cells totipotent and therefore provide an alternative non-controversial method of making totipotent stem cells? 164.107.102.191 (talk) 16:48, 18 November 2013 (UTC)[reply]

See our article Induced pluripotent stem cell, and these science articles in Science [2] and Nature [3]. It is not entirely clear to me how these are limited from being "totipotent" (e.g. is there some target cell type that they cannot become?), but maybe someone else can help clear that up. SemanticMantis (talk) 18:02, 18 November 2013 (UTC)[reply]

At least as concerns mammals, pluripotent cells can differentiate to form any cell lineage of the body, whereas totipotent cells can additionally form placental tissues [4]. For most biomedical research applications I would imagine there would be little difference (i.e. if you don't want to study placental tissue it doesn't matter), and in any case human stem cells generated "traditionally" (i.e. human embryonic stem cells) are pluripotent rather than totipotent. Equisetum (talk | contributions) 22:56, 18 November 2013 (UTC)[reply]

Also keep in mind it can just be a matter of evidence. In order to show the cells are truly totipotent you need to actually show them becoming every tissue type; but even making a chimera out of them can leave open a crack of doubt (since the natural cells might take over some fate they fail to adopt). Wnt (talk) 12:32, 20 November 2013 (UTC)[reply]

In the derivation for gravitational potential energy, we consider the work done by agent in bringing a particle from infinity is a constant for small displacement dx. but once the particle is in the gravitational field, the gravitational force done by an agent will reverse direction. in that case the work done by the agent is first positive and then becomes negative. do we really consider both the positive as well as the negative work? — Preceding unsigned comment added by 120.62.184.196 (talk) 16:56, 18 November 2013 (UTC)[reply]

I don't fully understand your scenario, but if you bring a point into a gravity well close to a planet, you'll get negative work out of it that you can use for kinetic energy, annihilating settlements from space, whatever you'd like. Now if you take it away again, out of the well, do you keep that energy, or do you have to give it back? If you don't count both positive and negative work, does that mean you have a plot of the energy you've extracted/put in that abruptly turns into a flat line at some point? Nature doesn't much like flat lines with sharp corners. So my assumption is that you need to count positive and negative, but depending on exactly what you want to calculate, you might end up defining your number differently. Wnt (talk) 17:14, 18 November 2013 (UTC)[reply]

which direction does Jupiter spot rotate?--Akbarmohammadzade (talk) 17:32, 18 November 2013 (UTC)[reply]

Our article is at Great Red Spot, and says "The GRS rotates anticlockwise, with a period of about six Earth days." SemanticMantis (talk) 18:04, 18 November 2013 (UTC)[reply]

As many animals become unsuitable as pets once they reach adolescence, and at the very least need to be castrated/spayed to make them manageable, is there any way to keep them young via drugs ? (Even if such drugs are prohibitively expensive when used for people, they might be offered more cheaply for animals, as many are.) StuRat (talk) 19:45, 18 November 2013 (UTC)[reply]

Do you mean freeze the aging process, or do you mean keep the pets small? 140.254.229.160 (talk) 21:15, 18 November 2013 (UTC)[reply]

You'd be looking at pituitary and genital surgery to remove the source of growth and sex hormones that cause puberty and increase in size. μηδείς (talk) 22:03, 18 November 2013 (UTC)[reply]

That may keep the pets small and infantile, but the pet itself may still age regardless in terms of how the other organs will wear out. 140.254.229.160 (talk) 22:10, 18 November 2013 (UTC)[reply]

I very much doubt Stu is asking about how to keep them young as in not old. Rather, the obvious issue is immature versus mature. Immature primates make good pets. Not so much so after puberty, and the same for most other wild animals. μηδείς (talk) 22:17, 18 November 2013 (UTC)[reply]

Ideally they would stop aging entirely, but I don't believe that's possible. What might be possible, though, is to prevent them from developing adult traits as they age. Yes, neutering them is one method, but I was asking if any drugs are available which can do this, as well. One option might be to prolong their juvenile state, but eventually stop the drugs and allow them to mature naturally. StuRat (talk) 03:48, 19 November 2013 (UTC)[reply]

Failure to develop in size and maturity naturally is caused by the lack of a hormone or a receptor for it. We can then possibly supply the missing hormone (not a missing receptor). But we don't usually give a drug to compete with or block a hormone. Such a thing is entirely possible, but were not at the stage where we can target such drugs to knock out certain types of development without possibly incurring serious, if not lethal side effects. At this point, physical removal of the relevant organs is the only practical option. For example, when my grandfather had terminal stage prostate cancer, they castrated him and put him on estrogen, which competes in some effect with testosterone, but would not entirely have masked it. I suggest looking at treatments for this and breast cancer and testicular cancer as well as acromegaly to see if any chemical treatments have the effect you want. μηδείς (talk) 18:10, 19 November 2013 (UTC)[reply]

Well, we've enforced neoteny through selective breeding of most out our domestic animals. See e.g. Neoteny#Domestication, Origin_of_the_domestic_dog#Neoteny_in_the_rapid_evolution_of_diverse_dog_breeds, Cat#Sociability, and even Self-domestication#Foxes. If there were currently any reliable way to push this trend further via drugs, rest assured that we would be inundated with advertisements for permanent kittens ;) SemanticMantis (talk) 22:32, 18 November 2013 (UTC)[reply]

A boy across the street from me in the 70's was famous for making permanent kittens. Until they stopped buying him replacements. μηδείς (talk) 02:15, 19 November 2013 (UTC)[reply]

Castrati used to be common. Had interesting side effects. Different than eunuch --DHeyward (talk) 07:25, 19 November 2013 (UTC)[reply]

From Chambers 20th Century Dictionary: Eunuch - means a castrated (ie testicles removed) male, especially one castrated before hormonal development; Castrati - means a male castrated before hormonal development and trained to sing. So no difference except that a castrati can sing, but a eunuch wasn't necessarily, and typically was not, trained to sing. So no real difference. 120.145.154.249 (talk) 15:39, 19 November 2013 (UTC) [reply]

OK, I know that this is not the language desk, but please, there is no such thing as "a castrati". --Trovatore (talk) 09:01, 20 November 2013 (UTC)[reply]

There must be, it's in the aforementioned dictionary. 60.228.253.116 (talk) 12:38, 20 November 2013 (UTC)[reply]

You're missing the point. Castrati is a word, but there is no such thing as a castrati, just as there is no such thing as a criteria, a phenomena, a bacteria, a biscotti, or a dice. --Trovatore (talk) 17:27, 20 November 2013 (UTC)[reply]

What you want is an axolotl, the Peter Pan of the pet world, but not so cuddly. Richard Avery (talk) 15:30, 19 November 2013 (UTC)[reply]

Axolotls can apparently be made to metamorphose into adults by giving them iodine, which is sort of the opposite of what Stu is asking for here ... maybe he'd like a functionally immortal pet Turritopsis_dohrnii ? SemanticMantis (talk) 16:34, 19 November 2013 (UTC)[reply]

How does tea with honey and/or lemon help hoarseness if food and drink descend down the esophagus and hoarseness originates in the larynx? DRosenbach ^{(Talk | Contribs)} 02:35, 19 November 2013 (UTC)[reply]

The Mayo clinic confirms that honey and lemon tea are both shown to be effective cough suppressants in clinical trials, but does not present a mechanism for how they work; merely noting that honey is shown to suppress coughs in children as effectively as dextromethorphan. --Jayron32 03:13, 19 November 2013 (UTC)[reply]

The obvious answer is vapors. For clearing my sinuses, I like to make a "tea" by dissolving menthol-eucalyptus cough drops in boiling water. That tea goes down my esophagus, too, but the vapors clear my sinuses right out. StuRat (talk) 03:43, 19 November 2013 (UTC)[reply]

I think every medicine has a "mechanism is unknown" in the PDR references. They can do studies to prove efficacy and limit side-effects but metabolism is so complex that it's generally impossible to have a complete mechanism. Therefore most of it is statistical. Kind of scary if you ask me. (I think they may finally have a complete mechanism for aspirin). Read a PDR on drug mechanism to be completely disheartened. --DHeyward (talk) 07:21, 19 November 2013 (UTC)[reply]

Yes, I just commented on this in another Q, how much of western medicine really is just trial-and-error, without knowing why things do what they do. StuRat (talk) 07:41, 19 November 2013 (UTC) [reply]

Not to mention being in part snake oil, as we see when pharmaceutical companies are forced to re-run clinical trials under more rigorous protocols. —Quondum 13:28, 19 November 2013 (UTC)[reply]

It's not like we know any more about honey and/or lemon. Honey having "anti-bacterial properties" as mentioned below is just as unknown a mechanism as other medications. Neither more understood or better than any other. --DHeyward (talk) 02:38, 20 November 2013 (UTC) [reply]

The heat of the tea will act as a painkiller, while the steam will carry the oils of the lemon into the sinuses. Honey is well known for its antibacterial properties. The larynx and associated soft tissues are close enough to the oesphagus to benefit from the heat of the tea. It's not just the larynx that may be inflamed or infected: the pharynx may be as well, or the tonsils or adenoids or the other fleshy parts. --TammyMoet (talk) 13:23, 19 November 2013 (UTC)[reply]

Our article on swallowing mentions that true vocal fold closure is the primary laryngopharyngeal protective mechanism to prevent aspiration during swallowing. The article is lacking in sources but see for example here. The epiglottis will fold over and cover the glottis, the upper esophageal sphincter first relaxes to allow the food or drink to pass into the esophagus and then contracts to reduce backflow into the pharynx. For liquids, this process won't be one hundred percent effective, there will always be some liquid sticking to the mucous tissue which may be redistributed when one swallows the next sip. Honey, with it's greater viscosity and stickiness may be able to reach the vocal cords this way. but that's pure speculation on my part. A youtube video showing the vocal cords and the epiglottis during swallowing here, and one showing radiology of someone swallowing barium here. Ssscienccce (talk) 14:37, 19 November 2013 (UTC)[reply]

"...clear my sinuses right out," and "... carry the oil of lemon into the sinuses", does that mean the nasal sinuses or the nasal conchae. If it is the former I am interested to know how the active agent enters the sinuses, given that access and egress is through a very small, and tight, meatus surrounded by cilia sweeping outwards. Sorry DR, well off topic, but sometimes one has to question stuff that people say. Richard Avery (talk) 15:25, 19 November 2013 (UTC)[reply]

You're quite right to question me Richard, and I'm wary of quoting my sources on here because I've been told off for quoting pseudoscience about aromatherapy before. The essential oil will be vaporised by the heat and carried by the steam into the nasal cavity, and from there into the sinuses at the front of the face, when the steam from the tea is inhaled. --TammyMoet (talk) 20:02, 19 November 2013 (UTC)[reply]

Well, I don't know for certain how it works, only that it works. It's quite possible the vapors are inhaled up the nose while drinking from the cup. StuRat (talk) 23:54, 19 November 2013 (UTC)[reply]

I can't definitively answer the OP's question either but I have a clue. In the UK, our equivalent is 'Simple Linctus.' [5] Something one gets from the drugstore that contains sucrose and citric acid. Many years ago when the these shops where shut for a bank holiday weekend I was given a tumbler of 'grandma’s' family sore throat cure. Ie., Tea with honey and lemon (and some of the zest). I can not rule out the placebo effect totally, because a spoon full of Simple Linctus just goes down the gullet where as a tumbler (about 1/3 of a pint) of warm sweet lemon tea is more enjoyable and may therefore, have put me in a more optimistic frame of mind. However, lets go back to the OP's question and the Larynx. I noticed (and other times since then) that as the hoarseness and soreness faded away, I stated to sound like Paul Robeson [6]. Being a natural baritone I found it delightful to go suddenly reallllly deeeeep. So to address Drosenbach question, I am wonder that if during a viral infection, the epiglottis (through evolutionary fitness) closes to prevent phlegm entering the larynx (and down into the lungs). Thus, causing dryness of the vocal cords. Honey and lemon (and not the proper prescribed tonic, which I now think does B*@@$& all) both soothes and relaxes the epiglottis and allows the vocal cords to become moist once more. Whilst at the same time allowing the odd bit of thick mucous to sometime coat the cords allowing me to sing “ Oh, That Old man river ... that old man river... --Aspro (talk) 22:30, 19 November 2013 (UTC)[reply]

I know that radon is odorless, at least to us, but i wonder if a dog could smell it, or otherwise detect ionization from the radioactivity or smell the lead byproduct or or other byproducts. thanks!67.177.40.9 (talk) 15:07, 19 November 2013 (UTC)[reply]

No, I don't think so.

• Radon itself is a "noble gas" - it doesn't react chemically with anything - which means (I believe) that it truly is odorless and tasteless, even to dogs.
• The radiation also has no "smell" because the sense of smell operates by detecting molecules using chemical reactions.
• I could easily believe that a dog could be trained to pick up some kinds of by-products. Radon changes to Polonium with a half-life of 3.8 days - which over a few minutes turns into lead. I doubt that enough polonium stays around for long enough for a dog to pick it up. But training a dog to sniff out minute quantities of lead ought to be possible.

But there is a horrible snag. The problem is that the dog would need to detect very small quantities of lead - which I'm sure it could do - but there is almost certainly going to be lead from other sources in the area where you're trying to do the measurement. If you want the dog to sniff out radon by-products in someones' basement for example - then if it's sniffing for lead, it's going to find it in the solder joints of copper household piping, in the solder joints of any electronics, in pottery glazes...all over the place!

Since the dog can't tell the difference between lead-from-radon and other sources, it can't detect the byproducts of Radon.

So this hinges on whether it could smell the truly tiny number of short-lived polonium atoms in the few minutes between the radioactive decay of a radon atom and the polonium atom turning into lead. But polonium is almost as unreactive as radon - and also, polonium is found in places that might fool the dog - smoke detectors, for example, contain small amounts of the stuff - but in quantities that would dwarf the amount in the air of a radon-infested basement.

I couldn't find a reference for any of this - but I'm pretty sure the reasoning is sound.

SteveBaker (talk) 16:31, 19 November 2013 (UTC)[reply]

A good undergrad-level chemistry question is "given the half-life of the relevant Rn isotope and the amount of radiation detected, what is the concentration of Rn in the air?" Helps focus attention on orders of magnitude...what can a radiation detector or (bio)chemical sensor detect and also sensitive instruments such as mass spectrometry (all the "immediate detection" methods vs requiring long-term collection/concentration steps). DMacks (talk) 17:27, 19 November 2013 (UTC)[reply]

Another point to consider is the difference between the sensitivity of a detector and its accuracy. A dog's nose is very sensitive, so dogs are very good at detecting whether something (drugs, explosives, cancer cells) is present in a sample, but the important thing we need to know is how much radon is in the basement, which dogs aren't particularly good at communicating. Tevildo (talk) 18:42, 19 November 2013 (UTC)[reply]

Physically, we know it is possible for some devices (Geiger counter) to detect the radon radioactivity. Therefore, there is no physical law that prevents the dog from detecting it with some similar function. It may seem far-fetched, yet it has been suggested at times that people living in areas with high background radiation have some ability to acclimate (radiation hormesis). That is a controversial idea itself, but clearly, if something can acclimate, if its biology is literally reacting to the radiation somehow, then in theory it could sense that and react to it by behavior also. At this point, the only biological answer possible is to do the experiment and see what happens. Wnt (talk) 18:44, 19 November 2013 (UTC)[reply]

That's one hell of a stretch. Mainly though - even if by some as yet unknown mechanism, it were possible for a higher animal to detect radiation like that, why would you assume a dog could do it any better than a human or an aardvark? Sure there is a physical mechanism by which humans can detect high levels of radon gas - by breathing it for 30 years and dropping dead from lung cancer if radon gas is present. The problem here is not that there might or might not be some physically plausible way to measure it - the specific question is whether a dog can do it using it's superior sense of smell...and the answer is an almost-certain "No". Let's try not pretend to be clever by mudding the water and thereby confusing the people asking the questions here. SteveBaker (talk) 21:59, 19 November 2013 (UTC)[reply]

"Common sense" is not very reliable in biology. For example, people have been studying cancer in mice for a century. Then one day someone happens to ask whether the risk of cancer depends on the temperature of the room. [7][8] And guess what? It's been throwing off the results. Before something very similar came out about common formulations for mouse chow. It's very important to keep in mind the difference between what you think is the answer and whether you know the answer in this field. There's no reason for dogs to have evolved to sense radiation unless somebody finds out they do it, at which point it will take a researcher or commentator all of five or ten minutes to come up with some just-so story to explain why they did. Wnt (talk) 12:26, 20 November 2013 (UTC)[reply]

• Neither the shape theory of olfaction nor the vibration theory of olfaction would rule out smelling a non-polar substance. If the ability doesn't exist, it might be more of a case of (the lack of) selection for the relevant genes. μηδείς (talk) 22:23, 19 November 2013 (UTC)[reply]

Xenon is a "noble gas" but does produce strange phenomena like anaesthesia. Shyamal (talk) 13:13, 21 November 2013 (UTC)[reply]

But that is not a result of its chemical properties, right? Double sharp (talk) 14:33, 21 November 2013 (UTC)[reply]

To give some idea of the quantities involved: 1000 Bq/m3 would be considered a very high concentration for a house. One Bq is one atom decaying per second. Radon has a half-life of 3.8 days, reversing the calculation of Becquerel#Calculation_of_radioactivity gives us about half a billion particles (per cubic meter); that's about 8 x 10^-16 of a mole, and with a cubic meter of air containing about 45 moles, the concentration in the air is about 1 particle in 5x10¹⁶. Dogs can detect explosives in concentrations of 1 ppb, and some dogs have been shown to detect some chemicals at concentrations down to 1 ppt. But even 1 ppt is 50,000 times higher than the radon concentration at 1000 Bq/m3. Considering the fact that a dogs nose will likely be much less (if at all) sensitive to radon and its progenies, the only way to detect radon would be if the concentrations were millions times higher than normal... Ssscienccce (talk) 16:09, 21 November 2013 (UTC)[reply]

This storm recently killed a number of people in Sardinia. But do cyclones occur in the Mediterranean? Our cyclone article makes no mention of that area. Which type of storm is it? Who is the official name giving body for this storm? Or is this like The Weather Channel naming U.S. winter storms? Rmhermen (talk) 17:05, 19 November 2013 (UTC)[reply]

Sort of quasi-cyclones -- see Medicane. Looie496 (talk) 17:28, 19 November 2013 (UTC)[reply]

What's a medicane -- is it like our Witch of November? I presume it's not the brand name of a walking stick, or of a medicated candy cane ;-) 24.23.196.85 (talk) 21:30, 19 November 2013 (UTC)[reply]

I couldn't find any reference to this kind of thing happening over the Mediterranean - Europe in general seems pretty much devoid of that kind of activity. One exception (which I recall well because I was living right in the middle of it at the time!) is the Great Storm of 1987 - which hit France and southern England - but not the Mediterranean.

According to Hurricane#Naming, hurricanes are named either by the World Meteorological Organization according to a fixed rota of alphabetically consecutive names - or sometimes by national weather offices. Tornadoes are generally named after the place they touch-down - but it's all a bit informal. We have an entire article about Tropical cyclone naming.

That same article says "Tropical cyclone formation is rare within the Mediterranean sea...and as a result there are no official naming lists for these areas.". Evidence, again, the Great Storm of 1987 - which had no 'official' name but is universally known in the UK just as "The Great Storm" and the Burns' Day storm which is named for the birthday of Robert Burns (a Scottish Poet).

European windstorms (which are really "extratropical cyclones" tend to go north of the Mediterranean - mostly missing Europe completely. There is a section in that article that explains the naming system...but it's not a well-organized, or recognized system - and different countries frequently give the same exact storm different names.

SteveBaker (talk) 17:31, 19 November 2013 (UTC)[reply]

Well, European windstorms mostly miss continental Europe, but they frequently hit Scandinavia. In the British Isles, they frequently hit Scotland but rarely make it down to England. If they hit England they can do a lot of damage, but in Scotland, as somebody said, they usually just knock the cows over. Looie496 (talk) 17:57, 19 November 2013 (UTC)[reply]

I saw an advertisement for an artsy bottle opener that said it was "3D printed stainless steel". This seems a little beyond 3D printing technology as I know it. How would this be possible? --209.203.125.162 (talk) 18:48, 19 November 2013 (UTC)[reply]

If you Google "3D printed stainless steel" or similar, you'll find lots of services that provide exactly that. Shapeways has a 3D printed stainless steel Klein bottle-shaped bottle opener that shows up on their main page. TenOfAllTrades(talk) 19:34, 19 November 2013 (UTC)[reply]

(ec) Doing it properly involves Selective laser melting - alternatively, according to this website, "3D printers deposit small drops of glue onto layers of stainless steel powder, one layer at a time, until the print is complete.... The models then go through an infusion process that replaces the glue with bronze, creating a full metal product." Your bottle opener is probably made by the latter method, but it can be done. Tevildo (talk) 19:35, 19 November 2013 (UTC)[reply]

In a tank duel between our Sherman tank and the Russian T-34, which side is more likely to win? And what factors (if any) would help one side or the other? 24.23.196.85 (talk) 22:02, 19 November 2013 (UTC)[reply]

We don't do speculation here. SteveBaker (talk) 00:15, 20 November 2013 (UTC)[reply]

Our article discusses this for late models of each tank. See Sherman tank#Post–World War II. Rmhermen (talk) 01:10, 20 November 2013 (UTC)[reply]

Thanks! So, slight advantage for the Sherman because of better optics and a higher-velocity main gun, just like I suspected? 24.23.196.85 (talk) 03:32, 20 November 2013 (UTC)[reply]

Not necessarily. That section seems rather incomplete. See Sherman versus T-34 for more pros and cons. I'm no expert, so I can't voice an opinion of its accuracy, but it doesn't contradict what little I've read. Clarityfiend (talk) 06:22, 20 November 2013 (UTC)[reply]

Our article on the T-34 mentions that the Germans operated a number of captured T-34s. I wonder if any of these were used on the western front, which may have given us an actual example of T-34 vs. Sherman combat. Someguy1221 (talk) 06:27, 20 November 2013 (UTC)[reply]

According to this forum, no. It really wouldn't make much sense to ship them across Europe. A better scenario is one of the 4102 Soviet Lend-Lease Sherman tanks vs a captured T-34 on the Eastern front, but I'm sure somebody would have brought it up long before if it had happened. Clarityfiend (talk) 04:33, 21 November 2013 (UTC)[reply]

I've looked and I can't find the answer to this question (two parts):

1. If all (or essentially all) of the electricity was produced by means that don't burn fossil fuels, would that be enough to halt global warming?
2. If not, what if all (or essentially all) automobiles didn't burn fossil fuel - would that be enough? Bubba73 ^{You talkin' to me?} 06:20, 20 November 2013 (UTC)[reply]

There are also other sources of atmospheric greenhouse gases, like slash-and-burn agriculture. And things like solar panels may not be a solution at all, if it takes more energy to produce them than you get out of them over their lifetime, and this energy comes from burning fossil fuels. StuRat (talk) 07:24, 20 November 2013 (UTC)[reply]

Yes, I know, but I saw somewhere that producing electricity was the biggest contributor to carbon in the atmosphere and automobiles were second. Bubba73 ^{You talkin' to me?} 18:13, 20 November 2013 (UTC)[reply]

That varies a bit by country. Here is the EPA data for the US in 2011, where indeed electricity (33%) and transportation (28%, note that that includes air travel, shipping, railroads, and trucks) are indeed the largest producers. Attribution of recent climate change has world-wide data for 2000, and for all GHG emissions, not just CO2. Cutting our GHG emissions to about one third would go a long way to reducing the medium-term risk of global warming, but we are already committed to significant future warming, since the planet has not yet caught up to the current imbalance we have created.--Stephan Schulz (talk) 18:31, 20 November 2013 (UTC)[reply]

Have a look here [9]. It's not exactly what you are talking about, but very similar. This type of analysis is often referred to as a "wedge" approach to halting/reducing climate change, so that term might help your searches. According to the graph I linked, all renewable and high-efficiency electricity would not halt climate change, but for vehicles they just have an "efficiency" wedge, which I think still means fossil fuels are used. Another thing to keep in mind is that there is a sort of momentum involved with atmospheric dynamics and CO2 emissions. Thus, even if we could halt all CO2 emissions today, the climate would likely still warm for several years, and it would take hundreds to get back to pre-industrial levels of atmospheric CO2. Hope that helps, I can dig up science articles on the topic if you'd like. SemanticMantis (talk) 16:26, 20 November 2013 (UTC)[reply]

Even if we were to do nothing more than stop burning fossil fuels today (just so we can all breath cleaner air, if nothing else) the planet will still go through a period of several decades of warming before settling on a new stable, but higher temperature. See this source. Hence we need to put a stop to the pollution and clean it up too ASAP. -Modocc (talk) 19:46, 20 November 2013 (UTC)[reply]

What effect does masturbation have on sperm count and the ability to have children? 94.124.154.253 (talk) 07:47, 20 November 2013 (UTC)[reply]

According to Masturbation#Evolutionary utility, masturbation can increase the ability to have children, by flushing stale sperm with low motility out of the male's genital tract, making way for fresher sperm with higher motility. Red Act (talk) 08:15, 20 November 2013 (UTC)[reply]

Cool! Thanks for that! This non-signed-in user can continue his self-pleasuring habit, safe in the knowledge that it is all in the interests of protecting his progeny. 94.124.154.253 (talk) 08:29, 20 November 2013 (UTC)[reply]

Continue that lifestyle and you won't have to worry about any progeny. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:04, 20 November 2013 (UTC)[reply]

And it's good for you. AndrewWTaylor (talk) 12:20, 21 November 2013 (UTC)[reply]

Water will evaporate because the energy is distributed evenly in the water, and as a result some water molecules near the surface will have enough energy to escape the liquid. The water vapor that forms will eventually be at room temperature though. So if the water vapor is below its boiling point, why doesn't the vapor condense into water droplets? Why does it take a certain concentration of water vapor for droplets to form? 74.15.137.253 (talk) 13:08, 20 November 2013 (UTC)[reply]

Could it be surface tension based? It might take a certain amount of moisture to be present to cause molecules to come together to form droplets 217.158.236.14 (talk) 13:38, 20 November 2013 (UTC)[reply]

Fundamentally the reason is entropy (or, more specifically, Gibbs free energy for your constant pressure/temperature environment): there are more ways to scatter your water molecules around the room than there are to arrange them in water droplets on the floor (nevermind restricting it to the glass), so that's the preferred state. However, if the water takes up any significant fraction of the available (sealed) space — which is to say that there's your certain concentration present — then the space available to the liquid water is comparable to that available to the gas, so the advantage of the liquid state (its lower internal energy) becomes significant and not all of the water evaporates. --Tardis (talk) 14:08, 20 November 2013 (UTC)[reply]

Another way to think of it is to consider the Boltzmann distribution of the water molecules at any given temperature. See This image. At any given temperature, molecules of a substance are not all at the same energy. They exist in a distribution of energy states, and some water molecules will always have enough energy to escape the liquid phase. Those that are already in the gas phase will also be in a Boltzmann distribution, that is some number of water molecules will be moving slow enough to be "captured" when the land on the liquid phase, and thus condense. The issue is that at any temperature, you don't have all of the molecules at the same energy. You always have a distribution of molecules at various energies, and some will have enough energy to remain in the gas phase. Notably, we have Ludwig Boltzmann to thank for both the concept of entropy (the explanation given above) and for the explanation I have given here; neither if a "better" reason, and really are just two different sides of the same coin; just different perspectives for looking at the same concept. --Jayron32 00:38, 21 November 2013 (UTC)[reply]

I think water vapor does always condense into water droplets, but at the same time those water droplets are evaporating, so you get an equilibrium, and only when conditions are right does that equilibrium favor water droplets large enough to see. StuRat (talk) 06:19, 21 November 2013 (UTC)[reply]

Why are technetium and promethium radioactive although they are in between stable elements? Czech is Cyrillized (talk) 13:32, 20 November 2013 (UTC)[reply]

To really understand this, we need to explain why any nuclide is radioactive. We can summarize by saying that the nucleus is in an unstable energy configuration, and the release of a particle (by radioactive decay) puts the nucleus into a lower energy state. This is correct, but it's nearly equivalent to saying "it's radioactive because it is radioactive."

What we need is a good model of the energy configuration of the atomic nucleus. It would be great if we could show you an analytic equation, into which you could plug the number of neutrons, the number of protons, and calculate the binding energy of the nucleus. Unfortunately, nuclear chemistry is very much an empirical science. We know the binding energies for various configuration only based on experimental observations. When we try to write analytical equations for small nuclei, we might make a little progress with, say, the quantum mechanical Yukawa potential (that is, if we attempt to express the energy of the strong nuclear force in a quantum mechanically correct way). But for large nuclei - the really interesting ones, particularly those that undergo radioactive decay - these models just don't work. The formulas predict incorrect values, and worse yet, they're entirely unwieldy, because they're set up to handle a small number of particles.

So, we're back to a little bit of hand-waving: some nuclei are unstable; we know they're unstable from lab measurements, but we can't easily explain why. Atomic physics really isn't very intuitive: in the macroscopic world, if you take an unstable physical dynamic system (let's say, a bowling ball glued to a stretched slinky, hanging over a ledge, and oscillating back and forth), you can't make it more stable by adding another bowling ball. One bowling ball is about to break away; two bowling balls are going to break away faster. More mass, more force acting against the adhesive property of the glue, faster "decay rate." Adding mass and energy and momentum in the macroscopic world changes the dynamics, but it often makes an unstable dynamic system more unstable. In the case of nuclei, adding mass and energy and momentum sometimes makes the system more stable. If we had a predictive model explaining why - in the general case - then I never learned about it, and I spend a lot of years studying atomic and nuclear physics. Nimur (talk) 13:56, 20 November 2013 (UTC)[reply]

It's certainly empirical like you said, but a useful summary of the relevant ideas is found in the Mattauch isobar rule. You can also start with the very simple observation that even numbers (separately) of protons and neutrons improve stability, in a theoretically-justified manner analogous to electron pairs. --Tardis (talk) 14:14, 20 November 2013 (UTC)[reply]

When by itself the Technetium-98 nucleus is stable. And it only changes due to electron capture. In an atom it can captures an electron and decay. Graeme Bartlett (talk) 21:30, 20 November 2013 (UTC)[reply]

(Since all isotopes of Sm are predicted to be capable of decay, is Pm really between two stable elements? Just a thought. Might it be better considered theoretically to not so much be unstable among stable elements, but just have a half-life much less than the elements around it?) Double sharp (talk) 14:21, 21 November 2013 (UTC)[reply]

Why there are patches of a brick-like surface on columns which appear to be of marble? Is it some other material, that reveals such weird layer when aged? 93.174.25.12 (talk) 15:21, 20 November 2013 (UTC)[reply]

You are probably seeing modern-era masonry reinforcement that has been used to re-build the column.

My favorite example of this is Baalbek, which I have visited many times. It's ancient; some of the temples pre-date the Roman era.

People kept destroying the temple, and then rebuilding it; every few hundred years, some messiah or pagan or Jewish revolt would occur, or Persians or Greeks or Franks would invade, and everyone would sack and loot every temple for hundreds of miles. There were periods throughout history during which tourists would have to wait a few decades until the preservationists could rebuild the temples. Around 500 CE, a major earthquake knocked over most of the columns, except for six very tall columns; and the archaeologists and preservationists decided to keep it that way, because the ruins looked "pretty" and "ancient." Unfortunately, there were still a few thousand years of war and catastrophe left for human history to experience; so the ruins had to be re-preserved (back to their ruinous state) following the arrival of the Arabs, and the Crusaders, and Napoleon's army, and a few decades of cold-war era bombings, hijackings, occupations, antiaircraft batteries, airstrikes, and so on.

The last time I went to Baalbek, the columns were still pristinely preserved in their ruinous state, and are usually nicely lit up with colorful electric lighting.

Archaeologists and preservationists at such sites have to be very careful about their strategy; ancient "restoration" work becomes part of the site history; even if it is cosmetically dissonant from the original site. (In fact, to restore Baalbek to its pre-Byzantine glory, we would need to disassemble the Hagia Sophia - the foundations of which were built from parts that Justinian sacked from Bekaa; any proper "restoration plan" would make a lot of people very unhappy).

I would be very interested to read more about Volubilis, if anyone knows a good history book. Nimur (talk) 15:41, 20 November 2013 (UTC)[reply]

(For anyone who is interested in some lighter recreational reading on the topic, I highly recommend the art and architecture picture-book series produced by Phaidon Press, a publishing house which was for a time staffed by the better half of the Encyclopedia Brittanica team. This one is particularly worthwhile, though I don't remember if it covered Morocco in great depth). Nimur (talk) 21:53, 20 November 2013 (UTC)[reply]

For a while, I thought planets around orange and red dwarf stars the planets around it can develop advanced life forms, more advanced than it can get up to humans. But my teacher told me developing life forms around orange and red dwarf main sequence stars can be harder because of the solar flares. But the thing is orange and red dwarfs stars have 10s or 100s of billion years to linger on main sequence than how can planets around the stars have hard time developing lives. Because some people thinks if at all they can only get up to simple life bacteria on planets around red dwarfs, how come life development is than slim, when small red stars have 10s or 100s of billion years to live on main sequence? Can small orange star planets reach the life forms get up to human types, or its life available on the harbor planets have to be more limited (at most hit up to life developed to Cambrian period? Orange dwarf stars have reduced luminosity, it have 10s or 50s billion years to linger on main sequence. Is the problems reduced luminosity, requiring CHZ to be closer to the parent star, or is it reduced ultraviolet radiation and solar wind, making greenhouse gases hard to escape from planets. Can too little solar wind cause problems on planets making greenhouse gases hard to escape?--69.226.32.110 (talk) 05:59, 21 November 2013 (UTC)[reply]

Any answer we give is outrageous guesswork. However, I am suspicious that ultraviolet light plays an important role in getting the ball rolling, because it's a source of direct energy to create different kinds of reactions. See [10] for an example. Wnt (talk) 06:25, 21 November 2013 (UTC)[reply]

Also note that the greenhouse effect isn't always bad. First, if a planet is so far away or the star is so dim that it would be too cold for life, then some greenhouse effect can bring the temperature up to something better for life. Second, a thick atmosphere helps keep the temperature more constant between day and night, which promotes life. Third, even a case of "runaway greenhouse effect", like on Venus, might tend to favor some forms of life. On Earth we have organisms that live around black smokers and such, where conditions aren't that far off from Venus. StuRat (talk) 07:04, 21 November 2013 (UTC)[reply]

In discussing the possibilities of terraforming Mars, Carl Sagan said that we would necessarily have to create a greenhouse effect and global warming there. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:25, 21 November 2013 (UTC)[reply]

It isn't just the greenhouse effect. The Martian Atmosphere, according to Mars, has an average surcace pressure of about 600 pascals. Earth has an average surface pressure of about 100 kilopascals, making the Martian atmosphere less than 1% as dense as the Earth's. That's a LOT of gases in general you'd have to import to Mars to get an atmosphere which is breathable, never mind warm enough, for people to survive. You'd need an atmosphere that is about 75-80% inert gas and 20% oxygen to be breathable, and to get THAT atmosphere on Mars is just a lot of matter to get onto that planet. Besides the fact that the lack of a magnetosphere means that the solar wind is constantly stripping said atmosphere away, which is a problem Earth doesn't have. --Jayron32 14:13, 21 November 2013 (UTC)[reply]

There are two very distinct questions here:

1. What is needed for life to initially develop? ...and...
2. What is needed for it to continue to survive after that?

We know that extremophiles from Earth can live in outrageously nasty conditions (by human standards at least!) - but that only answers part (2) of the problem. Perhaps life needs a very special set of precise conditions to initially develop from inert compounds (this is called "abiogenesis"), but once it has a toe-hold, evolution is certainly capable of adapting initially fragile life into extremophiles who could live in all manner of difficult places. We can say with some degree of certainty that given time to adapt, Earthly life could evolve to survive on the surface of Venus, or even Mars - perhaps in oceans under the ice of various moons, for example.

But the tricky part is (1)...What does it take for life to initially develop? Because science does not yet know (for sure) how that initial abiogenesis step happened here on Earth, we have no idea what conditions were necessary for it to happen. Worse still, we can only possibly know those conditions for DNA/RNA-based lifeforms like all of life on Earth. We can't say what it would take for a lifeform based on some other scheme entirely would need.

Hence, we can discuss with some degree of accuracy whether DNA/RNA life could continue to exist on a suitable planet orbiting at an appropriate distance around a Red Dwarf - but we have absolutely no clue whether life could initially develop there.

Worse still than that, there is an increasing body of evidence for the "panspermia" notion that life didn't even develop here on Earth - but that it was carried here on a meteor or comet from some other place. If that turns out to be true, then perhaps life doesn't have to develop around a Red Dwarf - maybe it develops right here on earth, gets shot out into space following a giant impact early in our history - then sails gracefully through space until it hits a small planet orbiting Proxima Centauri (a red dwarf just 4 light years away) - and survives long enough to evolve to live underground or deep underwater - where it's protected from solar flares or whatever.

When you put together panspermia as a means for life to develop someplace different from where it currently lives - with the "we have no clue" answer to what Earth-like DNA/RNA life took to develop - and toss in the possibility of life based on other forms of biochemistry - then coming up with bold statements like "Life can't exist around Red Dwarfs" starts to look like a completely untenable claim.

Let's go one step further. There is no reason to believe that mankind won't one day soon figure out how to make self-reproducing machines - robots that can mine materials and be powered by solar panels and which can make more robots. That seems entirely possible. It's also quite reasonable to imagine that we could engineer such a thing to live near Proxima Centauri. Now you have to ask yourself whether our definition of "life" (which is exceedingly hard to pin down) should include artificial self-reproducing entities? If so, then an advanced civilisation living on a twin planet of Earth might quite easily have seeded planets orbiting Red Dwarves with this kind of "life" billions of years ago - which may in turn have evolved into advanced beings who are most certainly "alive" by any reasonable standards - and living absolutely anywhere where there is a source of raw materials and sufficient energy to keep them running (albeit very slowly).

The universe is huge, and incredibly ancient - I don't see any reason why life should not exist in every conceivable niche - however seemingly hostile. However, there are very likely to be some fairly strict limits as to where life can initially develop - but we don't have any idea what those limits are, and don't let anyone tell you otherwise!

So - feel free to ignore your teacher - let your imagination roam free - and perhaps gently suggest that he or she try to think outside the box for a while before making such bold (and clearly unsupportable) claims.

SteveBaker (talk) 14:50, 21 November 2013 (UTC)[reply]

We actually have an article about it: Habitability of red dwarf systems. main problems: low energy output so small habitable region close to the star, planets being tide-locked so no day-night sequence, tidal heating may boil the planets, solar output could vary up to 40% due to sunspots (compared to 0.1% with our sun), massive solar flares could strip the atmosphere... Ssscienccce (talk) 18:08, 21 November 2013 (UTC)[reply]

What is the Boeing 787 Dreamliner's minimum takeoff distance when it's carrying the minimum possible weight, including very little fuel? The article talks about its minimum takeoff distance when fully loaded, and this news article does too, but nobody seems to talk about whether the airplane in the article could fly to its intended destination if they unloaded it and moved the freight to the destination airport by road or a smaller airplane. 2001:18E8:2:28C9:F000:0:0:A11E (talk) 14:37, 21 November 2013 (UTC)[reply]

I was wondering that too. But it wasn't a 787 doing the delivering, right? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:36, 21 November 2013 (UTC)[reply]

Indeed not, it's a modified 747 cargo aircraft. Page 9 of this paper gives the critical runway length (that is, if one engine fails during take off, something they have to worry about) for two different 747 variants, at 3000m and 3500m respectively (it's about 75% of that as long as all the engines work okay). That variant is different, and may be a bit heavier due to its larger fuselage, but that's the rough distance. -- Finlay McWalterჷTalk 16:03, 21 November 2013 (UTC)[reply]

Although those are MTOW (maximum take off weight) numbers. I don't know if they publish minimum weight numbers. -- Finlay McWalterჷTalk 16:06, 21 November 2013 (UTC)[reply]

Indeed, they do - they define the legal and safe weight and balance envelope. The pilot in command of the aircraft must crunch the numbers to ensure that the airplane weighs enough - if it is too light, or if the weight is improperly distributed, the aircraft will be aerodynamically unstable. In such circumstances, when a large aircraft ends up at a tiny GA airport, or the length of the runway with respect to the takeoff roll is doubtful, the aircraft may not be legally certified to take off. The aircraft operators then file for a ferry permit with the local FSDO (part of the FAA), who may allow the aircraft to take off below its legal minimums - or outside its ordinary category envelope - provided that it is actually capable of the flight. If it's marginal, the operators may wait for a much colder and windier day (with a lower density altitude and a solid headwind) to bring the takeoff roll even shorter. Nimur (talk) 16:22, 21 November 2013 (UTC)[reply]

And the runway at Colonel James Jabara Airport is 1,860m. -- Finlay McWalterჷTalk 16:07, 21 November 2013 (UTC)[reply]

In the United States, we measure runways in feet: AAO has a 6101'x100' runway. Normally I advocate the SI system of units, but there are times when it is inappropriate to require a unit conversion, such as during the landing of a large aircraft. The POH specs takeoff rolls in feet; the FAA's charts and data sheets spec airfields and elevations in feet; the altimeters are measuring in feet, the radio communication uses feet. Nimur (talk) 16:32, 21 November 2013 (UTC) [reply]

The aircraft concerned is a Dreamlifter, not a Dreamliner. Very different (and very different from a normal 747, too). - David Biddulph (talk) 16:34, 21 November 2013 (UTC)[reply]

If they're going to want to unload it (I don't think I've seen a news report that says whether it is loaded) then that would prove a logistical challenge too. The gigantic DBL-110 "Dreamloader" is "half the width of a football field", putting it about 20m wide - it'll be very hard to get one of those to the airfield. -- Finlay McWalterჷTalk 16:59, 21 November 2013 (UTC)[reply]

Oh, it's far worse than that! The aircraft is too large to turn on to a taxiway! It's still on the runway, which is why the FAA filed this NOTAM:!AAO 11/009 AAO RWY 18/36 CLSD 1311211440-1311212200. The runway is shut down for all other landing or departing aircraft! Nimur (talk) 17:08, 21 November 2013 (UTC)[reply]

This report says that the tug to turn the aircraft around has arrived, that they can take off, and that they intend to do so "around noon" today (an hour or so from now). -- Finlay McWalterჷTalk 17:18, 21 November 2013 (UTC)[reply]

That article says that after takeoff it "will then land at McConnell Air Force base and unload, as planned." Thincat (talk) 17:36, 21 November 2013 (UTC)[reply]

I never heard of a Dreamlifter before, so I guess I misread the original news article. But doesn't "half the width of a football field" mean bigger than 20m? When we Americans talk about something being the size of a football field (or half, or whatever), we normally mean its length. Boeing 747 Large Cargo Freighter has a wingspan of 211 ft 5 in, which is a width vaguely close to half of an American football field's length of 360 feet. 2001:18E8:2:28C9:F000:0:0:A11E (talk) 17:37, 21 November 2013 (UTC)[reply]

It's the Dreamloader, the machine they use for loading the Dreamcarrier (with bits of Dreamliner), that's about 20m wide. -- Finlay McWalterჷTalk 17:50, 21 November 2013 (UTC)[reply]

The article that Finlay linked earlier actually specified: "The longest in the world at 118 ft., 1 inch, this loader was designed and built in less than 15 months by TLD at its facility in Sherbrooke, Quebec." I wonder if Boeing managed to make Québécois use feet and inches, or if 118'1" is "conveniently close" to 36.0 meters!

I joke, but only partly: confusion between metric and "standard" Canadian units was the reported root-cause for the 1983 Gimli glider fueling mishap, one of the most famous aviation incidents in Canadian history. Nimur (talk) 18:43, 21 November 2013 (UTC)[reply]

... and we should draw a veil (or shroud) over the Mars Climate Orbiter. Thincat (talk) 19:05, 21 November 2013 (UTC)[reply]

Update on KWCH's front page: they got the plane off successfully, and it landed safely at its intended destination :-) 149.160.168.94 (talk) 20:21, 21 November 2013 (UTC)[reply]

It being Kansas, which is pretty much flatland, and depending on how far apart the airports are, it might be easier just to close off the roads for a while and drive it there. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:21, 21 November 2013 (UTC)[reply]

Why do some rollerball pens produce occasional splodges of ink even if they're fine most of the time? What corners have been cut? --129.215.47.59 (talk) 16:01, 21 November 2013 (UTC)[reply]

Do artificial sweeteners turn to formaldehyde in the human body? — Preceding unsigned comment added by 170.142.177.85 (talk) 20:23, 21 November 2013 (UTC)[reply]

Aspartame does - see Aspartame#Metabolites. Saccharine, sucralose and cyclamate don't. Tevildo (talk) 20:39, 21 November 2013 (UTC)[reply]

If you had smoke particles from a fire stuck in some ones lungs than could bacteria that consume those elements be able to consume what’s in the lungs? I doubt the bacteria would survive the environment of the lungs, though I've no references to say they couldn't temporarily, or if frozen. I imagine building and vehicle fires involve a lot of different elements, so you would need a wide variety of bacteria; but if you had such a bacterial Noah's arc, than would this be theoretically possible? Also, is there seriously no academic journal that even suggests the idea of phlegm bacteriotherapy, I can only find references to fecal bacteriotherapy. CensoredScribe (talk) 20:52, 21 November 2013 (UTC)[reply]

Are there Europeans or ‘white’ people who are born with black patches on their skin? --66.190.69.246 (talk) 20:58, 21 November 2013 (UTC)[reply]