Do I have to rename all creatures in a new world?

Question: I'm building a whole new world for a table top RPG so I don't want to completely alienate my players from the world. But if I want to include horses or whales, do I need to reinvent the wheel and make a "horse-like" creature instead? What are the drawbacks?
Comment: *Never* do that. A horse is a horse. Only invent a new name if the creature is sort-of like a horse, but it still has important differences -- maybe it eats meat, maybe it has six legs and so on; and in this case use a new name, and provide somehow (either organically or through exposition) the background that is behaves and it is used kinda like horse.
Comment: Try to avoid [calling a rabbit a "smeerp"](https://tvtropes.org/pmwiki/pmwiki.php/Main/CallARabbitASmeerp) (warning: TVTropes).
Comment: 'pine apple' is an example of how far the english will go to not call something the same thing as someone else - almost everyone else knows pineapples as 'ananas' lol
Comment: @Spencer, on the other hand, [calling a "smeerp" a rabbit](https://tvtropes.org/pmwiki/pmwiki.php/Main/CallASmeerpARabbit) can be a good source of humor, particularly when you point out that a Sphinxian chipmunk has six legs and looks nothing like a chipmunk.
Comment: If George didn't have to do it, you don't have to do it neither. https://starwars.fandom.com/wiki/Duck/Legends
Comment: @cyber101 Pineapple is the Anglicized version of Piña, not something English made up whole cloth.
Comment: DWShore, we generally regard it as appropriate to wait at least 24 to 48 hours to award best answer, otherwise it discourages others from answering  (perhaps even giving better answers - we don't all live in the same time-zone as you). It's quite acceptable to withdraw that award, then re-apply it.
Comment: We even didn't invented new names for things on this world. For example - pine apple.
Comment: @Chickensarenotcows: Good to know, thanks for the heads up. (I'll review again in a day or two).
Comment: Changing ALL the names could be funny for a short while, with the right (or very, very wrong) group of players. Not what you want right now, but I laughed while imagining it, thought someone else might as well.
Comment: Just a comment: the horse-form is an excellent example for convergent evolution, there are many unrelated, but very similar horse-like creatures on Earth, because that form is so efficient. So there are even scientific reasons why you might find horse-like animals somewhere else, if the environment is similar. And why wouldn't you call a horse horse?
Answer:
"Kalgash is an alien world and it is not our intention to have you think that it is identical to Earth, even though we depict its people as speaking a language that you can understand, and using terms that are familiar to you. Those words should be understood as mere equivalents of alien terms-that is, a conventional set of equivalents of the same sort that a writer of novels uses when he has foreign characters speaking with each other in their own language but nevertheless transcribes their words in the language of the reader. So when the people of Kalgash speak of "miles," or "hands," or "cars," or "computers," they mean their own units of distance, their own grasping-organs, their own ground-transportation devices, their own information-processing machines, etc. The computers used on Kalgash are not necessarily compatible with the ones used in New York or London or Stockholm, and the "mile" that we use in this book is not necessarily the American unit of 5,280 feet. But it seemed simpler and more desirable to use these familiar terms in describing events on this wholly alien world than it would have been to invent a long series of wholly Kalgashian terms.
"In other words, we could have told you that one of our characters paused to strap on his quonglishes before setting out on a walk of seven vorks along the main gleebish of his native znoob, and everything might have seemed ever so much more thoroughly alien. But it would also have been ever so much more difficult to make sense out of what we were saying, and that did not seem useful. The essence of this story doesn't lie in the quantity of bizarre terms we might have invented; it lies, rather, in the reaction of a group of people somewhat like ourselves, living on a world that is somewhat like ours in all but one highly significant detail, as they react to a challenging situation that is completely different from anything the people of Earth have ever had to deal with. Under the circumstances, it seemed to us better to tell you that someone put on his hiking boots before setting out on a seven-mile walk than to clutter the book with quonglishes, vorks, and gleebishes.
"If you prefer, you can imagine that the text reads "vorks" wherever it says "miles," "gliizbiiz" wherever it says "hours," and "sleshtraps" where it says "eyes." Or you can make up your own terms. Vorks or miles, it will make no difference when the Stars come out.

-- Isaac Asimov's introduction to Nightfall (with Robert Silverberg), 1990
Comment: Talk about bringing out the big guns...
Comment: The *biggest* gun, singular.
Comment: This answers both my question, and the follow up questions I had. I will avoid making up names just to muddy the waters.
Comment: In contrast to Asimovs answer, I'd recommend reading Neal Stephenson's "Anathem" as an example of striking the right balance between inventing new words and using plain english for things. Stephenson introduces them slowly, consistently and always in a way that you can gather from context what it is (plus, he provides a glossary with the paraphrased comment "if you like a bit of a challenge, don't use it"). In addition, those invented words use some particles from known languages, e.g. Arbre (Earth), Cartabla (navigation tablet), Speely (movie), Reticulum (internet), ...
Comment: @orithena "Anathem" is an interesting case as the words may be fabricated, but their meaning can be readily surmised by their similarity to actual English words - they have common Latin-esque roots.  Take for example "avout", which is used as basically the opposite of "devout", and you can figure that out just by looking at it and having a basic understanding of English linguistics.  This is a far cry from the "vorks" and "znoobs" of Asimov's example, which have no relation whatsoever to anything in English.
Answer: Well, you're not only building a world, you're also building a game, and this changes everything.
If you want an immersive experience with a world that feels different, brand new creatures are a must. They can be "inspired" from earth creatures, but in the end this won't be a "we changed the skins but they are the same" output, as every change will have cultural and practical results. But it will be awesome.
On the other hand, if you don't want to have to explain everything all the time, using earth-like creatures will both save you an insane amount of brain-time and will help your players to better imagine what you're speaking about.
Remember, this isn't a novel, it's a shared fantasy with your players. With a role playing game, it's generally accepted that the endgame isn't the worldbuilding or the balance within the rules, but the fun itself. So... this world you're building, in the end it's a tool to improve on this. To have fun.
If your game is about immersion and you (and your players) don't mind the descriptions, full creation is great. Sometimes, a horse can be much more than a horse.
If your game is about actions, you can use archetypes and hit the ground running! After all, your players know what the concept of a horse is, so they can hit the ground running. If you do it this way, don't change the names, as it would be counter-productive for you to create a world with easy-to-understand concepts... and then make sure nobody gets them at a glance. These are tools to your game. Use them properly.
You can go halfway, too. To introduce a "horse-like creature" is a good way to minimize descriptions and explanations while keeping a door open on exotic creatures and cultures. You have to be more careful, though, because your players might assume some things about these earth-like creatures, and if you see things differently it will fudge their plans and lesser the overall experience. This is still the way most authors and developers go.
Whatever you do, in the end, always remember this this is for fun. Yours and you players.
Answer: The technical term for this is 'calling a rabbit a smeerp'. In other words, taking something which exists on Earth and give it an alien name just for show. The rule of thumb when writing is to only call alien things by alien names when they are functionally distinguished from the Earth counterparts. Not merely different, but perform a functionally different role.
So, say a normal rabbit - not a smeerp. A blue rabbit - a bit better, but not exactly a smeerp. Maybe drop a line about it. A blue rabbit which has poisonous fangs and can see in the dark - smeerp!
Answer: Ursula K. Le Guin (tried to find the original text from her but didn't) wrote something about neologisms. It was about tech (not creatures). She said that if something is well known, use it (don't rename it). That sci-fi is a bigger thing than your story, a growing body, where things are created and live.
So for creatures, I usually use the same reasoning. If it's a horse, I call it horse. If it's a horse with wings, I call it a winged-horse or a flying horse. I also use general expressions from biology, like quadruped and herbivore for alien fauna, instead of making up new terms.
If you look up scientific names, classes, expressions from earth's biology they are actually very surprising and alien. They can be a great source of inspiration.
Comment: IIRC, Le Guin was commenting on how her term 'Ansible' had become standard sci-fi parlance for instantaneous communications devices.
Answer: Vary the familiar within the landscape of the known.
If you make everything weird and invented, it can feel contrived.  Readers / players have to learn everything new.
If you have a "strange new world" but your characters are basically cowboys, it feels lazy.
I propose you vary the familiar within the realm of the known.  Examples:

In the movie Princess Mononoke, Prince Ashitaka rides a red elk.  There were horses in the movie, but having him ride an elk set him apart from the people around him.  An elk is not that weird.  For its part in the story his elk could almost have been a horse - a large quadruped, loyal, herbivorous.  But when it did things like jump very far that could be explained by the fact that is was an elk.

In the book Hiero's Journey (an inspiration for many far future post apocalyptic SF scenarios), Hiero rides a psychic moose.  It is horselike for purposes of being a mount but it has some other abilities.  Fun stuff and also not super outré because most folks are familiar with the starting point of "moose".  Plus mooses are great.

If horses seem boring but you don't want the place your characters sit to be the focal point of novelty and innovation, use a real nonhorse animal for your mounts.  Choose according to the ecosystem your players will traverse.  Remember that people rode wagons and then chariots before they rode atop horses.  There are more animals that could pull a chariot than could be ridden with a saddle.  Chariots are not weird inventions but neither are they what cowboys and knights ride.
I once spoke with a zookeeper at the San Diego who clearly had a rapport with the giraffes.  I asked if he thought they would pull him in a chariot and he got very happy speculating about how that might be done - clearly an idea that sparked his imagination.
Re whales - whales are pretty spectacular as is.  An omnivorous whale would be interesting for an RPG.  Seeing a blue whale rip into a carcass would be pretty alarming.  There are lots of other real creatures which could or did fill the niche of whales in the history of the world.  Or you could use sea monsters - Heuvelmans categorzied them in his book In the Wake of the Sea Serpents and you could borrow some of his.  https://mythology.wikia.org/wiki/Sea_serpent
Answer: My rule of thumb is that if it fulfils a similar function or fills a similar niche then call it by the name but you can point out the differences. Above all keep it simple.
It can be saddled and ridden then why not just call it a horse? It may have scales and antennae but it fulfils the function of a horse, just refer to it first time as a scaly-reptilian horse and thereafter just a horse.
In-game you may need to specify the horse in detail for encounters, combat etc. and deal with scaly armour or night vision but then in any normal fantasy RPG a horse needs to be specified as there is a huge difference between a Hobbit's pack pony and the furious ton of meat, muscle and armour that is a Paladin's war horse.
If you create a whole new creature then by all means name it or if you create an animal that either does not have an earth parallel or else has too many parallels then name it . For example if you have a long thin furry legless creature that lives under ground is it an elongated legless ferret? A furry snake-mole?
The only other thing I would suggest is that if this is a new world colonised by immigrants (like the US or Australia) then the immigrants tend to bring with then names from the old country. Many 'New World' places were named after the hometown of the settlers, similarly many animals were named for similar looking animals from home. There is a robin in the US named after the European robin just because it looks similar-ish.
In your world it is plausible, if not expected, for the incomers to name a horse-like creature a horse.
Answer: I don't know if this would be annoying for the players, but I would use different spelling and unicode characters to slightly alter the spelling of the word, make it recognizable and readable, but alien enough that in the mind of the player/reader it can easily be some other creature
For example,

a rabbit could be a rābeet
a horse would be a hőƦsƎ
a cat could be a katt
a dog would be a Ɖǒǥ

So you would choose a font that has all of these characters, in a way making your own alphabet used only for creatures, places, general objects (maybe you also have some special swoūrd that has a really weird shape, but cuts like a sword), but not for regular story telling.
Comment: This seems like it would be hell to read, especially for people with dyslexia. Sure people could figure it out given time and effort, but it's time and effort I don't usually have to spend to understand the words I'm looking at.
Comment: @Draconis that's true, I didn't think about people with dyslexia. But I think the regular gamer wouldn't have a problem with this. There are a lot of games that have weird characters and fonts, especially RPGs, so a lot of people would be used to reading weird words.
Comment: I find this sort of thing more annoying than smeerp.
Answer: You can take the example video games set (since you're also building your world for a game). Basically, in video games, most worlds are just like Earth, until they're not. What does that mean? They use the Earth template as long as it suits them, whenever this template needs editing (new creatures, new deities, new races, etc) they do just that. For example, The Witcher series added a lot of creatures, while still keeping some that are familiar to us. Everything else is pretty similar to medieval Earth. The Elder Scrolls series added magic and deities, while still using the medieval Earth template. Also, they can remove items from the template that don't suit them, just like the Fallout series did with the transistor. I think this is what you should do with your world, build it like Earth, and alter it in ways that suit your objectives.


Google site verification of www https site redirected from domain

Question: I have an Apache Tomcat 8 web app correctly running on my website that is reverse proxied to the Apache2 server which serves up the web app at my domain name. I then provided alias' in my site's conf file in Apache2, and in my DNS Record in my site's DNS Record Management, to redirect http://www.example.com to http://example.com. That all works. I set up Apache 2 to serve the alias www.example.com to domain.com, and have used Let's Encrypt to redirect all http://example.com and http://www.example.com to https://example.com. I encrypted for http://example.com only since encrypting for both domain.com and www.example.com cause my www.example.com browser address to not redirect to example.com (and subsequently to https://example.com). So my browser all works good for either http://example.com or http://www.example.com to redirect to https://example.com. The problem is that in Google Webmaster Tools the site verification for http://www.example.com fails. Says unable to connect to server. Seems the Google verification does not do a redirect. Any insight into this would be appreciated. Thanks in advance.
Comment: Please include your redirect code. Otherwise, how would we know?
Comment: I'm able to verify my redirecting properties in Google Search Console.   "Can't connect to the server" sounds like the server went down or is not available.   It doesn't sound like a problem with the redirects to me.
Answer: I used the DNS Text Record method for Google site verification. I didn't know the DNS provider so I used Other, making the Text Record at A2 Hosting, and waiting for the DNS changes to propagate. All works now. Thanks for the replies.
Answer: From your site admin, go to Navigation.
Click URL Redirects:
Click Add URL redirect:
Enter the old URL you want to redirect visitors from in the Old URL field. Only broken URLs should be redirected. ...


Does the series $\sum_{n=1}^\infty \left|\frac{\cos2^n}{n}\right|$ converge or not?

Question: $$\sum_{n=1}^\infty~\left|\frac{\cos2^n}{n}\right|$$
I just confused what to do.
I am sorry, i don't understand. But this task is important for me. Can you give full solution?
Answer: Hint: Use the double-angle formula for $\cos x$ to show that in each pair of successive terms, at least one term has $|\cos 2^n| \geq \epsilon$ for some fixed universal $\epsilon > 0$. Then use that to prove the series diverges.
Comment: I must use Cauchy's convergence test?
Comment: @slmkarta Just take the terms in consecutive pairs, and show that for the $n$th pair you have that the sum of the two terms is greater than or equal to $\epsilon / 2n$. So then your series diverges by comparison test because $\sum_n (\epsilon/2)/n$ diverges.
Answer: I guess the homework tag has now become irrelevant and it's about understanding the argument. So let's spell out what user2566092 hinted.
The addition theorem for the cosine is
$$\cos (x+y) = \cos x \cos y - \sin x \sin y.$$
Specialising $y$ to $x$, we obtain the double-angle formula
$$\cos (2x) = \cos^2 x - \sin^2 x.$$
With the identity $\cos^2 x + \sin^2 x \equiv 1$, we can write that as
$$\cos (2x) = \cos^2 x - (1-\cos^2 x) = 2\cos^2 x - 1.$$
If $\lvert \cos x\rvert$ is small, then $\cos^2 x$ is very small, and $2\cos^2 x - 1$ is close to $-1$, and therefore $\lvert \cos (2x)\rvert$ is then not small.
We can quantify that: If $\lvert\cos x\rvert \leqslant \frac{1}{2}$, then $0 \leqslant \cos^2 x \leqslant \frac{1}{4}$, and $\cos (2x) \leqslant 2\cdot\frac{1}{4} - 1 = -\frac{1}{2}$, so then $\lvert \cos (2x)\rvert \geqslant \frac{1}{2}$. Thus in the sequence $a_n = \lvert\cos 2^n\rvert$, of every two consecutive terms, at least one is $\frac{1}{2}$ or greater. Therefore, grouping two consecutive terms, we see that
$$\sum_{n=1}^{2k} \left\lvert \frac{\cos 2^n}{n}\right\rvert \geqslant \sum_{m=1}^k \frac{\lvert\cos 2^{2m-1}\rvert + \lvert\cos 2^{2m}\rvert}{2m} \geqslant \sum_{m=1}^k \frac{1/2}{2m} = \frac{1}{4}\sum_{m=1}^k \frac{1}{m} > \frac{1}{4}\log k,$$
which shows that the series does not converge.


debugging remote event receiver using service bus not working

Question: My scenario is i had a working application that i was able to debug perfectly some month back using service bus but is not working anymore. I don't have any errors and none of my breakpoints are hitting. I have seen that service bus are now using sas connection string and remote event receiver uses acs. Can someone help on this issue please.
Answer: Found the answer.
I have attach a cloud debugger to the project and it does the trick.


Hard Sci-fi energy shields

Question: I'm making a fairly hard Sci-Fi story, and I was wondering what the most scientifically plausible 'energy shield' (for ships and stations) would be. My world tries to remain true to basic physics, but I'm not researching every law and limit to get it perfect. If it's not possible by our current understanding of physics, what should I change to minimize the number or obviousness of the flaws in its plausibility?
Comment: Is this shield supposed to absorb only space dust, or also weapons' fire?
Comment: I'm quite certain this is not answerable as a [tag:hard-science] question, per the definition of the tag. Tag removed.
Comment: [Related](http://worldbuilding.stackexchange.com/questions/14999/deflective-properties-of-a-forcefield).
Comment: Weapons-fire as well; I believe basic armour should be able to handle space dust and the like. With electromagnetic guns and energy weapons it would be thoroughly infeasible to have plating thick enough to deflect or absorb the projectiles, so I'm looking for alternate ways to do so.
Comment: @PavelJanicek This is not a Hard Science question, per the tag definition. Science-based, yes, but not hard science. The tag was already removed before because of this.
Comment: @ThalesPereira OK, sorry :)
Comment: I'm voting to close because we don't really know the purpose of the shield. Is it to protect against metallic bullets, good old rocks and ice, or nasty missiles and torpedoes, for instance? How are ships working in this universe, e.g. : Do they use a lot of metal like nowadays? Are they limited in power output? Knowing this would have allowed far more accurate answers for the intended effect (See how some of my examples make the accepted answer using magnetism less relevant, if not just dangerous ^^).
Answer: Same as Earth's, which serves us well: magnetism.
magnetic field
A superconductor can be charged with a huge current that then acts as an enormous permanent magnet.
A ship may need to handle dust and gas moving at high speed relative to the ship, but that material is not charged. So charge it: spray electrons to charge dust (like a room ionizer does) or use a laser or tuned microwaves to cause gas to become ionized.  Also, might say that the corona effect magnifies the results and sweeps away more than you explicitly ionized (though it's not obvious that that would be the case in a near vacuum).
physical swarm controlled via flux pinning
If you want something to affect material near the ship to serve as protection, you are asking to change the momentum of that stuff. What could do that without contact is electromagnetism or gravity. That is, an "energy shield" is electromagnetic, with no other reasonable choice.
With "contact", you can still avoid walls by spraying small particles out. The corona effect uses electric charges to accelerate charged particles which then smash into other particles, pushing them away.
The idea of shielding that's not simple walls is useful for constant renewal rather than wearing out, and being stronger than mere matter.  Something that is really cool to see demonstrated is the use of superconductors to "pin" an object in a definite position in space relative to each other, with a sizable gap between but acting like a solid object.
So, have a swarm of small magnets surround the ship, some distance  from each other but with enough layers that the swarm is opaque. An incoming rock will hit one of the plates and not make it through the swarm.  Each magnetic plate is covered with spongy material, so the hit will accelerate the plate without (typically) breaking it. The plates are far enough apart so it won't knock into another.  But, the displaced chunk is loose and did not fracture a large normal object like a plain matter shield.  After absorbing the energy, the superconductor takes on the energy while slowing the motion, then returns it to its proper position.
The plates can be made with weak seams crossing it where it will break in a controlled manner if hit too hard; and each piece is still controllable as part of the swarm.
The swarm can be dynamically reconfigured, to beef up the direction where hits are expected, such as the direction of travel or where debris have been spotted.
I've seen the superconductor station-keeping explained as possible for a structural component that won't "break" but can be returned to its proper position after being over-stressed. Using a swarm for shielding is an original idea.
Fans of the RI Christmas Lectures will recognise this demonstration.  Here is an overview which touches all the bases. I could not find a video of the particular demonstration that inspired me illustrating the strength of such bonds for structural elements in space construction.

See also this post.  See this paper for more on flux pinning for space construction.
Comment: Many thanks! I don't suppose this could be adapted to a 'force field' to, say, quickly seal a hull breach to prevent fatal decompression, or perhaps a restraining utility? I think I'll go with an amalgam of your and Henry Taylor's answers, with some magnetic deflection and maybe some manner of flash-formed ablative coating. Thanks again!
Comment: The swarm could plug an opening, especially if that use is anticipated. Or, expanding foam patch bombs can be deployed using the same system of moving objects around outside the ship.
Comment: I just realized how similar in concept my answer (http://worldbuilding.stackexchange.com/questions/65720/shields-at-10-one-more-hit-and-what/65796#65796) is to yours - except I extended my shields using rotors and thread instead of magnetic superconductors and flux pinning
Comment: How would the swarm be dynamically reconfigured? Does the ship have a super conductor inside of it that can be moved? Does it have multiple super conductors whose properties can be switched on and off?
Comment: @DevourerOfStars you make patterns of current in the superconductor, which is surrounding the ship.
Answer: Physicist Michio Kaku discusses some possibilities for shielding on p. 9-10 of his book Physics of the Impossible, viewable on google books here:

The problem with electron beam welding, however, is that it needs to be done in a vacuum. This requirement is quite inconvenient, because it means creating a vacuum box that may be as big as an entire room.
Dr. Herschcovitch invented the plasma window to solve this problem. Only 3 feet high and less than 1 foot in diameter, the plasma window heats gas to 12,000°F, creating a plasma that is trapped by electric and magnetic fields. These particles exert pressure, as in any gas, which prevents air from rushing into the vacuum chamber, thus separating air from the vacuum. (When one uses argon gas in the plasma window, it glows blue, like the force field in Star Trek.)
...
But can the plasma window be used as an impenetrable shield? Can it withstand a blast from a cannon? In the future, one can imagine a plasma window of much greater power and temperature, sufficient to damage or vaporize incoming projectiles. But to create a more realistic force field, like that found in science fiction, one would need a combination of several technologies stacked in layers. Each layer might not be strong enough alone to stop a cannon ball, but the combination might suffice.
The outer layer could be a supercharged plasma window, heated to temperatures high enough to vaporize metals. A second layer could be a curtain of high-energy laser beams. This curtain, containing thousands of crisscrossing laser beams, would create a lattice that would heat up objects that passed through it, effectively vaporizing them. I will discuss lasers further in the next chapter.
And behind this laser curtain one might envision a lattice made of "carbon nanotubes," tiny tubes made of individual carbon atoms that are one atom thick and that are many times stronger than steel. Although the current world record for a carbon nanotube is only about 15 millimeters long, one can envision a day when we might be able to create carbon nanotubes of arbitrary length. Assuming that carbon nanotubes can be woven into a lattice, they could create a screen of enormous strength, capable of repelling most objects. The screen would be invisible, since each carbon nanotube is atomic in size, but the carbon nanotube lattice would be stronger than any ordinary material.
So, via a combination of plasma window, laser curtain, and carbon nanotube screen, one might imagine creating an invisible wall that would be nearly impenetrable by most means.
Yet even this multilayered shield would not completely fulfill all the properties of a science fiction force field—because it would be transparent and therefore incapable of stopping a laser beam. In a battle with laser cannons, the multilayered shield would be useless.
To stop a laser beam, the shield would also need to possess an advanced form of "photochromatics." This is the process used in sunglasses that darken by themselves upon exposure to UV radiation. Photochromatics are based on molecules that can exist in at least two states. In one state the molecule is transparent. But when it is exposed to UV radiation it instantly changes to the second form, which is opaque.
One day we might be able to use nanotechnology to produce a substance as tough as carbon nanotubes that can change its optical properties when exposed to laser light. In this way, a shield might be able to stop a laser blast as well as a particle beam or cannon fire. At present, however, photochromatics that can stop laser beams do not exist.

Also, metamaterials have been used to create "invisibility cloaks" that deflect light around them, as in the following idealized graphic:

Presently these only work to "cloak" very small objects at very specific non-visible light frequencies, but scientists hope in future to expand the technology to larger objects and a greater range of frequencies. So potentially a technology like this might be adapted to deflect lasers around an object. There is also an analogous idea based on metamaterials called a "universal mirror" which would reflect incoming light beams back in the direction of their source. This article on the "universal mirror" specifically mentions it might have applications in laser shielding:

The metamaterial could also act like a aggressive shield, protecting objects from airplane-based, high-energy laser systems, which are being developed by Boeing, by bouncing the lasers beam back at their source.

Finally, if you want to get into much more far-future technologies, potentially it might be possible to create something like an invisibility cloak by setting up a thin layer of "exotic matter" that would bend spacetime in a way that would deflect all incoming light, as discussed in this paper. This is a purely theoretical idea that would require a civilization to be able to create and control very high densities of exotic matter with properties that present-day physicists aren't sure are even physically possible, in ways that would also allow other far-future technologies like the Alcubierre "warp bubble" that would allow for a form of effectively faster-than-light travel.
Answer: Plasma Shields
Boeing's

Boeing's proposed system involves using a combination of lasers, electricity and microwaves to rapidly heat up the air between the vehicle and a blast. This heat creates a plasma shield that's denser than the surrounding air and able to deflect or absorb the energy from the incoming shockwave.

University spacecraft research

There would need to be a wire mesh outside the spacecraft and enclosing the plasma cloud. Electricity supplied to the mesh would keep an electrical current running in the plasma cloud and help confined it near the spacecraft.
Answer: Bent space shield.
Gravity is usually considered as a force and so I assert it meets the requirement of this question.  Gravity is not a real force but an apparent one - gravity emerges as a consequence of the ability of mass / energy to produce inhomogeneities in space: bent space.
To make the bent space shield, you would use negative matter much in the way it is proposed for use in making the Alcubierre drive.
https://en.wikipedia.org/wiki/Alcubierre_drive

Rather than exceeding the speed of light within a local reference
  frame, a spacecraft would traverse distances by contracting space in
  front of it and expanding space behind it, resulting in effective
  faster-than-light travel. Objects cannot accelerate to the speed of
  light within normal spacetime; instead, the Alcubierre drive shifts
  space around an object so that the object would arrive at its
  destination faster than light would in normal space without breaking
  any physical laws.

If you have the tech to make the drive, making an energy shield would be a lot easier.  You would bend space around the ship such that energy or matter entering one side of the field would continue on its path, but be routed through bent space around the ship and out the other side.  This is slick in that it works equally well for moving particles or electromagnetic radiation.  Even very energetic particles moving at relativistic speeds would be effectively rerouted.  The energy of the particle or radiation remains as it continues through bent space, out the other side and on away from the ship.
A side effect of this shield is that it would also be a cloaking device: the ship within this shield is invisible.  I am not sure what energy emitted from the ship itself does when it hits the inside of the shield.
An interesting thought experiment: what happens if a ship with a field like this rams a larger object?  Mass impacting the bent space field is routed through it.  Could a ship with a bent space shield fly through solid matter?  If it closed up any windows in the shield, could it fly through a star?

Thinking more on the concept - a ship could use the same negative mater for its warp drive and its shields.  But the stuff must be rearranged to serve these different purposes.  To activate the drive you need to take down the shield and move the negmat to the specific place you will use to generate your drive.  If you come out of warp, it will take time for the servos to redistribute the mass around the ship and generate your shields.  This helps make ships so equipped less overpowered and godlike - you cannot just invisibly and untouchably warp from place to place.
Comment: Star Trek had this to a certain extent - one of its universal constants is that you can't hit a ship while it is using its warp drive. The downside, of course, is that it can't shoot back.
Answer: The most common hard-science sheilding that I've encountered in fiction is ablative armor.  It isn't very elegant, but surrounding you ship with multiple layers of hardened foam provides a non-critical surface to catch the particles which get by your outer magnetic fields and inner swarm defenses.  As these particles collect, they provide additional layers of impact absorbing material to keep ever bigger particles away from your ship's atmospheric shell and other vital systems.
If really big particles get through, your foam armor can even break off during impact, carrying most of the momentum and mass of the collision away from your hull.  Then automatic foam dispensers on the hulls surface can replace the missing layers, preparing your ship for future impacts.
Upon arrival at your destination, you can either vibrate the hull to shake loose the remaining foam or bring the swarm in close to scrape the foam away from the outside in.
Answer: Essentially there isn't anything in hard science beyond maybe some of the ideas with magnetism and plasma. Active defenses (interceptor missiles, lasers, etc) are more plausible but still tricky.
Just dodging and getting out of the way is surprisingly effective, there is a lot of space out there and with no atmosphere to carry shockwaves near misses do very little damage.
If you have gravitational control in your universe then it's not hard science but you can see manipulated gravity fields being plausible as a defense mechanism. They could divert incoming fire away from your ship or even suck it into miniature black holes!
Answer: If your looking for something energy based, you could do a hard light shield by having a cloud of Rubidium around the craft and have weak lasers fire a few photons at a time (or scale up, the research is readily available) to create a hard light construct. Here's the paper on the experiment for generating hard light: http://www.nature.com/nature/journal/v502/n7469/full/nature12512.html
And a news article for summary: https://www.sciencedaily.com/releases/2013/09/130925132323.htm
Comment: The rubidium cloud in your linked articles is held near absolute zero; this is required to get the photons to slow down enough to form the 'bonds.' If I fired any sort of weapon that imparted energy to the field, it would break down the effect and leave you with an expanding cloud of rubidium dust and a few stray photons. Not a great shield.
Answer: Electromagnetic armor.
A concept being worked on in real world military applications. and "Exaggerated" in Scifi.
Idea is metal plates contain superconducting fibers, when energy/electricity is applied the molecules undergo a massive rigidity change. Increasing the hardness of the exponentially. Not a shield........but dynamic armor.
Comment: I always assumed the actual defensive effect was the arcing of the current and the counter "explosion" it created?
Comment: That's Scifi. The Defense sector is working to cordon off the blast by rapid expansion armor plate beyond. But that has no known counter to Armor piercing rounds that rely on kinetic energy.
Answer: There actually are examples of electro-static shields existing in real life by accident. Ridiculously dangerous of course. If it can stop you, it can just as easily kill you.
https://www.reddit.com/r/todayilearned/comments/7kv54c/til_a_3m_adhesive_tape_plant_accidentally_created/
My take would be on plasma shields with a twist. Basically, you take lasers that "print" small plasmadots in mid air, which then connect - allowing current to flow through, forming coils, em-fields and thus allowing "add-hoc" circuitry to be printed into any gasouse medium which the lasers can past and 3d print through.
So the shields do worker better in atmosphere - not so much in space, unless you bring your own medium-bubble.

Hard Sci-fi energy shields


Where to stay for London nightlife?

Question: For those looking to travel to London and enjoy the nightlife, where would be the best area to stay? Requirements are nearby bars, alcohol and 20-something crowd all preferably within walking distance.
Comment: hostel or hotel? That limits the choice further, as they aren't all in the same areas.
Comment: Just looking for some action, doesn't matter!
Answer: Well it's LONDON, so nearby bars and alcohol is almost redundant - they're everwhere ;)
Until around 12 at least.  Then the pubs close, and the nightlife and bars and clubs continue in certain areas.
The obvious is Central London.  Plenty of hostels and hotels.  Lots of bars and clubs open late especially around the touristy Leceister Square area, and Old Street area.
Expats often prefer Clapham Common, and to a lesser extent, Wimbledon - as the crowd is younger and it's far less touristy (and therefore cheaper).  A lot of Kiwis, Aussies etc, but then London is basically pockets of expats anyway :)
Comment: Note that when Mark says "Central London", he likely means the area near the Centre of London known as "The West End" - Actual "Central" London is the City of London, and not much happens there at night
Comment: Yes, that's why I specified around the touristy area, and Old St.  Certainly around say St Paul's at night, there's not much going on.
Answer: We all know that London is a city full of life and color so it is needless to say that the city has an amazing night life as well. The night life in London  attracts people from all age groups starting from the young teenagers to the old all are fascinated by the night life of London.There are plenty of bars and nightclubs in London such as Corsica Studios , EGG , The Den and Centro, Fabric ,THE ISLAND, 333 and many more.I suggest you central London would be your best choice to stay and enjoy nightlife and hotel charge comparatively cheaper in central London.
Answer: Budget: yha.org.uk - I've stayed at (several times):

St Paul's YHA in both dorms and single rooms. The nicest I think owing to the location (fairly good for East London (e.g. for Hoxton, Bricklane, Bow, Dalston), a (night) bus trip away). Cooked breakfast (was inclusive at the time)
Thameside in dorms. OKish for getting to East London (Rotherhithe station nearby). From there a lovely walk along the Southbank in the morning taking in all the arts establishments, Tate, South Bank Centre.

The worst that can happen in dorms is someone snoring continuously. Which occured to me about 1 out of every 5 times I stayed. Not bad run really!
couchsurfers.com can connect you with Londoners who have (possibly free) accomodation
Further up the price scale but more private, hotels: laterooms.com - still good value in some cases. Again, I've used this service several times in West London, South Bank, Camden, Greenwich.
Finally, another good way to find out about the nightlife is to listen to London radio stations. For example on iPhone/iPod/iPad and Android phones there is the TuneIn radio app which lists stations by region, including London. Kiss, Choice FM and Rinse FM will suggest urban, electronica and dance venues and club venues. Other stations will suggest rock venues for example. These would be available via PC/Mac as well by visiting their respective websites. Jazz FM heavily promotes venues in London and across the UK.
As a guess it also might be worthwhile visiting during the week - perhaps for a more authentic London crowd who can make such venues where as visitors perhaps less likely to. But then locals like to go out at the weekend too I would think.
Consider the time of year visiting. For example in the summer, festivals such as Lovebox have after parties, as will Notting Hill Carnival - some advertised as flyers others verbally.
Answer: Covent Garden could be a great option for you. Its right in the heart of London and you will get the exact kind of crowd you are looking for. Bars can be easily found around this place. My personal favorite is Thai Square restaurant and bar. Hope you have a good time.
Answer: There's two main areas in London that are known for their nightlife. London's Westend and Shoreditch. There are bars and clubs all over London, but places outside these areas are going to be a lot more local than bars in town.
The nearest station to the West End is Leicester Square. However the West End is associated a lot with tourists. Directly to the north of Leicester Square is Soho which is generally more local but still very buzzing on the weekend.
Shoreditch has many bars, particularity around Shoreditch High Street and Hoxton. Shoreditch is seen more "hipster" than the West End. Areas such as Dalston are seen as even more "hipster" than Shoreditch so plan accordingly.
One thing to remember is that if you stay in either of these areas is that they can be very noisy during the weekend, so it might be a good idea to find hotels just outside of these areas and walk in. Or just stay out to 2am... :) In Central London public transport is excellent and taxis are plentiful.
Covent Garden isn't really known for clubbing / drinking. Yes, there are bars and clubs here but the area is known more for the Arts (Opera House / Theatre) and its interesting shops rather than its clubs.
Answer: It depends really on what you're looking for quality wise really.
If your travelling on a budget I would recommend Generator hostels. Clean, tidy and really nice people. They tend to keep things under control so no crazy parties in the hallways. The Hostels are placed all over London.
Mid pricing you'd probably do well around the Kings Cross area in central London. Typically you can get a room for around £75-£100 per night in decent dwellings. Just don't expect mints on your pillow or room service.
High end stuff, well really the sky is the limit in London. Some hotel rooms come into the thousands... whilst others keep it in the hundreds.
If you do get a chance to explore the nightlife I would always recommend heading to Fabric, Ministry of Sound, Egg, Studio 338 and My favourite Boujis. Usually I just use Cluboid.com for guestlist or tickets to these events.

Where to stay for London nightlife?


help with permanent Redirect in .htaccess file

Question: I'm using plogger with wordpress and I'm in the process of moving current photos to new directories.  I need to setup a permanent redirect once I change the directory
For example.
Current location: www.mysite.com/products/cakes/birthday/batman-cake.html
New location:     www.mysite.com/products/cakes/superhero/batman-cake.html
So if someone types in the current location it should redirect to the new location.
I have 2 .htaccess files.  One in the root directory and one in the Plogger directory.  the plogger one I assume is used to make the urls pretty and I think this is where I need to make the changes.  Also I only want to redirect individual pages and not the entire directory
See the plogger .htaccess below.
<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteBase /products
  RewriteCond %{REQUEST_URI} !(\.|/$)
  RewriteRule ^.*$ http://www.mysite.com%{REQUEST_URI}/ [R=301,L]
  RewriteCond %{HTTP_HOST} !^www [NC]
  RewriteRule ^(.*)$ http://www.mysite.com/products/$1 [R=301,L]
  RewriteCond %{REQUEST_FILENAME} -d [OR]
  RewriteCond %{REQUEST_FILENAME} -f
  RewriteRule ^.*$ - [S=2]
  RewriteRule feed/$ plog-rss.php?path=%{REQUEST_URI} [L]
  RewriteRule ^.*$ index.php?path=%{REQUEST_URI} [L]
</IfModule>

Please note that someone set this up for me a while ago and I'm not a programmer but I'm a little technical.
Any help would be appreciated.
Thanks
Answer: <IfModule mod_rewrite.c>
  RewriteEngine on

  RewriteRule ^products/cakes/birthday/batman-cake.html$ /products/cakes/superhero/batman-cake.html [R=301,L]

  RewriteBase /products
  RewriteCond %{REQUEST_URI} !(\.|/$)
  RewriteRule ^.*$ http://www.mysite.com%{REQUEST_URI}/ [R=301,L]
  RewriteCond %{HTTP_HOST} !^www [NC]
  RewriteRule ^(.*)$ http://www.mysite.com/products/$1 [R=301,L]
  RewriteCond %{REQUEST_FILENAME} -d [OR]
  RewriteCond %{REQUEST_FILENAME} -f
  RewriteRule ^.*$ - [S=2]
  RewriteRule feed/$ plog-rss.php?path=%{REQUEST_URI} [L]
  RewriteRule ^.*$ index.php?path=%{REQUEST_URI} [L]
</IfModule>

Comment: I tried this but I always get a 404 page not found.  There must be something missing here.  The closest I can get to making this work for me is modifying the .htaccess file under the root directory as follows:                                                     Redirect 301 /products/cakes/birthday/batman-cake.html http://products/cakes/superhero/batman-cake.html?       The problem here is that I must put the trailing "?" question mark and this Always shows up in the URL.  Any other suggestions?
Comment: missed the trailing $
Comment: Still no luck, just getting the 404 page.  Any way to debug what is happening behind the scenes on my godaddy account?


DXA issue with special character in image names

Question: In DXA 1.4, when image name is having few special character it is not rendering on the web page. One of the example resolved image name is Service_&_Support_tcm12-12313.jpg. In page it is rendering encoded path(en/media/Service_%26_Support_tcm12-12313.jpg) but not showing the image. When I have tried to browse the image separately with url en/media/Service_%26_Support_tcm12-12313.jpg, it is showing error message Item '/en/media/Service_&_Support_tcm12-12313.jpg' not found for Localization '12'. Can anyone suggest if fixed this issue earlier. Thanks in advance.
Comment: Two things can be done.Either don't use special characters in the name of image or do explicit encoding for special char in code. I have encountered it once. For you '&' is encoded into %26 in the url.
Answer: This was a known bug in DXA1.2 but was stated on that ticket to have been fixed in 1.4.
However, there's a report regards the .Net implementation that this would be fixed in 1.5. The discussion by JordanRobinson is very interesting and may help you towards a workaround but fundamentally you'd be best advised to update the filenames.
Comment: Yes, it should be possible to use DXA 1.4 with CIL 8.2. You will need some (additional) assembly binding redirects in your web.config. To make it work. Note that upgrade from DXA 1.4 to 1.5 should also be quite easy.
Comment: The first issue mentioned was on DXA Java and that one was indeed fixed in DXA 1.4.
Ironically, a similar issue got introduced in DXA.NET 1.3 on Web 8. More specifically, the issue was in CIL 8.1 (used by DXA 1.3 and 1.4). The issue got fixed in CIL 8.2 (used by DXA 1.5).
Comment: +1 on filenames, but with the large collection of media if you are migrating it then its gonna be a challenge for sure.
Comment: Hey Rick, thanks for your comment here. Is there any workaround which I can do(may be temporarily) in my application code? May I use CIL 8.2 without upgrading the whole project to DXA 1.5? This is just to avoid any issue because of last minute upgrade of DXA version. Does that make sense?
Answer: The Query sent to the Broker to get the image will not return anything to your Model as the url sent for the request is wrong, hence you will not have it stored in your BinaryData/en/media/ as well, which leads to stop you not to use correct src url as well because there is no such image exists, moreover if any time there is no media returned from Broker, DXA would clean your BinaryData/media folder.
In my sugestion, Go with DXA1.5 where this is fixed with CLI 8.2 and if this is really not a good time to do that then please try to use Rick advice on this as also mentioned by Dylan above.
Note: if you know the media url and just want to decode it in your view, you would still not be able to get any image from Binary Data as Broker has not sent it there and Keeping them yourself is really bad idea.
Comment: Thanks Mark & Vikas for your responses. Indeed, shared urls are useful. I have tried, decoding url at application level. But it was not working. I am wondering if there is a quick fix possible at application level, without changing DXA codebase or migrating to a newer version. We have lots of images having special characters in the name.


How to cheaply extract iodine from an alcoholic solution?

Question: I have an alcoholic solution of iodine. My goal is to extract the pure iodine without using rare or expensive compounds. How could I do this?
Comment: Welcome to chemistry.SE! If you had any questions about the policies of our community, you can visit [the help center](http://chemistry.stackexchange.com/help) or take a [tour](http://chemistry.stackexchange.com/tour) of the website.
Comment: Is the solvent alcohol, literally? If so, is it 96% ethanol? Does HCl count as expensive for you? It would be nice of you to provide more info.
Comment: Yes it is 96% alcohol, and I do have HCl
Answer:
Alcoholic solution of iodine

What firstly comes to mind is that you meant "iodine tincture".
This question must have been frequently asked, since answers are available out there with different degrees of reliability. You must first follow the safety instructions:

Do your experiment somewhere that the noxious fumes won't be able to do harm to anyone. It's best to work under a fume hood.
You're gonna be dealing with strong acids. They're very corrosive when in contact with skin, metals or anything you can imagine (except glass).
Iodine tends to sublime. If not contained wisely, you'll get irritated skin, along with damages to your eyes (See about iodine hazards here).

In short, what you should do is:

Pour the tincture in a beaker, or any container. The important thing to note is to have "control" over what's happening in there.
Add water to the solution. The volume of the water you add should preferably be equal to that of tincture.
Add $\ce{HCl}$ to the solution, $\approx \pu{5-7 ml}$.
Add bleach to the solution, preferably equal or more than that amount of $\ce{HCl}$ you added.
Wait...wait...wait. For a relative amount of time, you should leave the solution for the reactions to happen.
You've past the hard part! Congratulations! Now, filter the dilute solution with a coffee filter.

Additional tips:

Iodine crystals sublime, so you shouldn't leave them in open air for long.
You should at least be wearing appropriate eye and skin protection. If you don't want them, do not do the experiment!

Wikihow has additional tips in case of any failures.
Sources:
http://www.wikihow.com/Extract-Iodine
http://www.sci-spot.com/Chemistry/iodine.htm
Comment: ...Or do exactly the same as above, but replace the 5-7ml of 'bleach' (sodium hypochlorite in an aqueous solution with stabilizers and possibly phosphates 'whitening' effect)  with 3-5ml 3% H2O2. Both methods produce free chlorine gas, which removes the sodium or potassium from the iodine.
Answer: Your best bet is to evaporate the alcohol from the solution to get Iodine. Iodine boils at $184.3\,^{\circ}{\rm C}$. But the vapor pressure of Iodine causes it to melt anyway. Note: Iodine does actually melt. To resolve this, take a watch glass and put it onto whatever you are using to heat the tincture. This will make the alcohol drip down the center of the watch glass as the iodine deposits/solidifies on the sides. To vent pressure, I recommend you to use a filtering flask and let some of the liquid condense in another flask. You can then re-evaporate. the liquid to get more Iodine. It should be impossible to to get 100% of the Iodine in the solution out, but is is pretty close.
Comment: Since iodine melts, the appropriate description of that temperature is a boiling point, not a sublimation point. There is also a bit of an issue with this, namely the fact that solid and liquid iodine have a significantly large vapour pressure. Simply heating a mixture will cause all the iodine to evaporate along with the solvents. http://chemistry.stackexchange.com/a/37416/16683
Comment: He was recommending multiple distillations.  Using a fractionating system might work or even vacuum distillation possibly (not sure which way the vapour pressures will swing).


What is the max ABV that can be attained with instant yeast?

Question: Wine yeast is not sold in Indian markets, and online it's very costly; around 12 times what it would cost in the US. I like wine above 15% ABV. Will that be possible with instant yeast? If so, then tips please.
Comment: If it's about making wine, I think you may have a bigger chance of getting an answer on [Homebrewing](https://homebrew.stackexchange.com/questions).
Comment: It wholly depends on which strain of yeast. (instant yeast will get you 3-6% of bread tasting mush)
Comment: i used rice wine yeast from ebay, that was very tolerant of abv
Answer: For fermenting with bread yeast most sources cite an average yeast alcohol tolerance of 13-14% AbV.  Obviously bread yeasts vary between manufacturers.
There are numerous other factors influencing attenuation, some common ones are:

concentration of sugars in the juice / must / wort
amount of yeast used
fermentation temperature

If your intention is to make quality wine, then it would be best to purchase a small amount of a purpose-bred wine making yeast, and grow it up into an amount large enough to ferment a batch.  Before pitching the yeast into the wine, reserve a small amount to grow up for the next-batch.  This method requires the least cost, but still ensures the yeast-type is appropriate for the beverage.
If you are making a "country wine" (fermented fruit juices, ginger "beer", flower-flavoured water+sugar, etc.) then bread yeast will be OK, but you would need to experiment to get the pitch correct.  For a rough idea, on a beverage that would ferment out to ~14% I would start with 40 grams* of dry bakers yeast into a 20 litre batch.
I strongly advise you to purchase a hydrometer so it's possible to monitor the performance of the fermentation.  Do this by taking a reading before pitching the yeast, and during fermentation.

My reasoning on this is the original gravity to produce this amount of alcohol would be quite high, say 1.1 SG / 23 Brix.  If this were beer, a pitch rate like this would be in order, and was verified with a pitch-rate calculator online.


Detecting changes in a web page's content

Question: I'm looking for an approach (not a library or framework, as I can't seem to find one) to detecting changes in a web pages content. I've taken a look at posts similar to Tracking changes to web page content, and white papers (http://shodhganga.inflibnet.ac.in/bitstream/10603/2415/14/14_chapter%205.pdf), but having trouble figuring out a good approach.
I don't believe an md5 of a page's content is useful, as the content of most pages change slightly depending on when you request it (eg. if they hardcode the day's date).
Additionally, I'd like to figure out a way to determine what content has actually changed (eg. running a diff on the content that is seen as different is good enough, but I would first need to figure out which content is different).
http://www.changedetection.com/ seems to do a solid job of this.
Any approaches or ideas or links would be appreciated.
Thanks.
Comment: Did you end up figuring out a solution to this?
Answer: The HTTP Last-Modified and ETag headers may be a way to go. However, if the web pages you crawl do not implement them, you are left with text similarity detection.


Topological relationships between family of transversal intersections of manifolds

Question: Let $M$ and $N$ be submanifolds of $\mathbb{R}^n$ and let $a(t)$ be a smooth path in $\mathbb{R}^n$ such that $M+a(t)$ intersects $N$ transversally for all $t \in [0,1]$.  Is there a nice relationship between the submanifolds $(M+a(0)) \cap N$ and $(M+a(1)) \cap N$?  Are they homotopy equivalent or better yet homeomorphic?
Comment: For the answer below: Don't we need some compactness assumptions on the submanifolds? What about $(0,1)\times\{0\}$ and $\{0\}\times (-1,1)$ where the map is given by a shift?
Comment: Thank you Oscar and Mark. Your answers are both helpful.  This seems like a natural question, and given that the answer is that the two submanifolds are homeomorphic (even diffeomorphic), this result must be well known. I wonder if there is a reference where it is stated explicitly?
Answer: Let me rephrase the construction: you have a map
$$\varphi : [0,1] \times M \to \mathbb{R}^n$$
which for each $t \in [0,1]$ is an embedding ($\varphi(t,x) = x+a(t)$ in your notation) and is transverse to $N \subset \mathbb{R}^n$. In particular, it follows that the map $\varphi$ is transverse to $N$, and so
$$X:=\varphi^{-1}(N) \subset [0,1] \times M$$
is a submanifold. If we write $X_t := \varphi(t,-)^{-1}(N)$ then this is a smooth manifold for all $t$, as $\varphi(t,-)$ is transverse to $N$: thus $X$ is a cobordism from $X_0$ to $X_1$, and these are the two manifolds in your question.
I claim that the projection map $\pi : X \to [0,1]$ is a submersion. To see this, note that for $(t,m) \in X$ the map
$$T_{(t,m)}([0,1] \times M) \to T_t[0,1]$$
is surjective, so we can find a $v \in T_{(t,m)}([0,1] \times M)$ mapping to $d/dt$. Under the surjective map
$$T_{(t,m)}([0,1] \times M) \overset{D\varphi}\to T_{\varphi(t,m)}\mathbb{R}^n \to \nu_{\varphi(t,m)}N$$
to the normal bundle of $N$, $v$ may not map to 0, but as precomposing with
$$T_{(t,m)}(X_t) \to T_{(t,m)}([0,1] \times M)$$
the map stays surjective, we can modify $v$ by an element of $T_{(t,m)}(X_t)$ (which does not change its projection to $T_t[0,1]$) to get a new $v'$ mapping to 0 in $\nu_{\varphi(t,m)}N$; hence $v' \in T_{(t,m)}(X)$, and it maps to $d/dt$ under $D\pi$, as required.
By picking a splitting of the bundle epimorphism
$$TX \to \pi^*T[0,1]$$
we get a vector field on $X$, and integrating this shows that $X \cong [0,1] \times X_0$. Thus in particular $X_1$ and $X_0$ are diffeomorphic, but even better, $\varphi\vert_X$ gives an isotopy between them in $\mathbb{R}^n$.
Answer: I believe they are homeomorphic.
Let $j: M\hookrightarrow\mathbb{R}^n$ denote the embedding of $M$. Your path defines a smooth homotopy $h: M\times [0,1]\to \mathbb{R}^n$ given by $h(x,t) = j(x)+a(t)$, and the assumption is that each $h_t = h(-,t): M\to \mathbb{R}^n$ is transverse to $N\subseteq \mathbb{R}^n$.
This assumption implies firstly that $h$ is transverse to $N$, and therefore that $W:=h^{-1}(N)\subseteq M\times [0,1]$ is a cobordism between $h_0^{-1}(N)=(M+a(0))\cap N$ and $h_1^{-1}(N)=(M+a(1))\cap N$ (cf. the Pontryagin-Thom construction). However, it is much stronger than that. These kinds of transverse homotopies have been studied by Jon Woolf and his collaborators (see http://uk.arxiv.org/abs/0910.3322, for example). The key observation is that, under these conditions, the map $W\subseteq M\times [0,1]\to [0,1]$ which projects onto the interval has no critical points (see http://uk.arxiv.org/abs/0910.3322 Theorem 2.3, which is about maps transversal to stratifications but the same reasoning applies to maps transversal to submanifolds). Therefore $W$ is a trivial cobordism, and the two ends are homeomorphic (this uses the ideas of Morse theory).
I guess this could be better explained. The slides here http://pcwww.liv.ac.uk/~jonwoolf/Slides/belfast-talk.pdf might be helpful.
Comment: Oscar beat me to it by a few minutes, but I thought I'd post the answer anyway in case you find the references useful.


Is it safe to use a former furnace flue to vent my dryer through the roof?

Question: Our dryer is located in the center of our house.  The current vent situation has tubing that makes several bends between the dryer and the crawl space before hitting metal duct that takes it about 25' across the crawl space to exhaust under our deck.  There are several elbows in this run.
We have converted from gas heat to an electric air-to-air heat pump in recent years and have closed up exhaust flue from the old furnace that starts almost directly above where the dryer vent leaves the dryer and comes into the furnace area before going through the floor to the crawl space.  If I redirect the vent up to the flue and out the roof, we'll cut a lot off the distance the air has to travel and remove most of the elbows.
Is this a good idea?
Answer: I have a funny feeling that local codes might preclude it. The problem is that lint will quickly clog the vent since once any lint collects on the walls, it will slow down airflow enough that lint will accumulate at the bottom of the vent. This can cause a fire.
Comment: Gravity acts on lint.  'nuff said.
Comment: My neighbor has a dryer vent run up through the roof (two floors), and as a result has chronic problems with the dryer not getting clothes dry enough.  As well, the vent clogs with lint requiring manual cleaning frequently (guessing yearly?)  So, I'd concur with woodchips' answer.
Answer: The dryer's installation instructions should specify maximum vertical rise of the exhaust vent. It's usually not that high, so it's unlikely your otherwise clever idea will work. If for some reason it's within spec, you'll need a different rain cap meant for dryers.
Answer: The only way you could use an existing flue for a dryer vent is if you can run a smooth 4 inch  metal duct down the flue to the dryer.  A masonry flue will capture lots of lint and plug up quickly, thus stopping any venting and creating a fire hazard.  The previous answers give good info, a good water tight cap and vertical venting specs are important.


Clefs used for pitched percussion

Question: I know that unpitched percussion instruments use the percussion/neutral clef. However, I was wondering what clefs are used for pitched percussion instruments. Are treble, tenor, alto and bass clef all used or are there any that are not ever used when notating pitched percussion?
Answer: Most pitched percussion is written on a treble clef staff. Vibraphone, chimes (tubular bells), and steel drums sound as written. Xylophone also uses a treble staff, but it sounds an octave higher than written. Glockenspiel (orchestral bells) and crotales sounds two octaves higher than written.
Exceptions:
Timpani parts are written in bass clef.
Marimba parts are often written like a piano part, that is on a grand staff (two staves - one bass clef and one treble clef).
I've never seen alto or tenor clefs used for percussion instruments.
Comment: Steel drums? Thought they were just played! Most players don't need music!
Comment: @Tim - there is a lot of music written for steel pans. Steelbands and orchestras of various sizes exist, and those players aren't just improvising ... somebody is writing those parts!
Answer: Music for pitched percussion instruments can be notated on a staff with the same treble and bass clefs used by many non-percussive instruments.
The term pitched percussion is now preferred to the traditional term tuned percussion:
Some percussion instruments, such as the timpani and glockenspiel, are almost always used as pitched percussion.
Some percussion instruments, and particularly many types of bell and closely related instruments, are sometimes used as pitched percussion, and at other times as unpitched percussion.
Keyboard percussion, instruments such as the glockenspiel and tubular bells arranged in a particular way (but not including the celesta and other keyboard instruments despite the name).
Melodic percussion, instruments used to produce several different pitches.
Everything of this answer is cited from wiki:
https://en.wikipedia.org/wiki/Percussion_instrument
https://en.wikipedia.org/wiki/Pitched_percussion_instrument
Comment: This doesn't address the OP's question. There is no mention of which clefs they read from.
Comment: I can  read: "Are treble, tenor, alto and bass clef all used or are there any that are not ever used?"
Comment: And the answer is: "Music for pitched percussion instruments can be notated on a staff with the same treble and bass clefs." (This implicites that the other clefs are not used.

Clefs used for pitched percussion


Italian Ricevuta / Travelling outside of Schengen

Question: I am a Turkish citizen who studies in Italy. My permesso di soggiorno (residence permit) is expired and I made an application for renewal. I have my ricevuta from the post office. I left Italy 10 days ago to have a trip in Balkans. Currently , I am in Serbia. Can I fly back to Italy from here via direct fly? I read couple of times ricevuta can be used only for travelling to home country. (Turkey in my case) But Italian police's web page doesnt specify something like that. It only says Italian residents can come back to Italy with their expired residence permit and ricevuta. I am thinking to go back to Italy with Ryanair. Is there a possibility for Ryanair to not recognize ricevuta and reject my boarding? Is there anyone who tried to travel from another extra-EU country to Italy with his/her ricevuta?
(I have seen another questions like this but they all want to travel to another Schengen country with their ricevuta.)
Comment: @Traveller the suggested duplicate concerns a trip to the Netherlands, which does not require passing the external border.  This trip, therefore, unlike the other, requires the traveler to clear Schengen passport controls.  Consequently, the airline's documentary requirements may well be different.
Answer: You should be able to fly directly to Italy from Serbia, or with a transfer in any non-Schengen country.  You would not be able to fly via another Schengen country.
The database that airlines use to check these requirements, TIMATIC, has this to say on the matter:

Visa Exemptions:
Passengers with a residence permit issued by Italy.
Additional Information:
Residents of Italy with an expired Residence Permit are permitted to re-enter Italy. They must also have a receipt issued by the Italian Post Office or Police Department proving that they have applied for the new residence permit in less than 60 days after the expiration date. They must return to Italy directly from outside the Schengen area.
Valid visas in full, invalidated travel documents are accepted if accompanied by a new travel document.


T&P Valve dripping after connecting new lines to water heater

Question: I put in a new bathroom right by my water heater, about 25 ft of hot and cold pex line. Ever since The day I turned on the valves to do a leak test, I've had a very slow drip from my temperature pressure valve on my water heater. It's only a drip every few hours, creating very little water, but it has been consistently dripping. I'm wondering why this is happening. Any thoughts?
Comment: What is the pressure in your house? Do you have a pressure reducer to lower city mains pressure to the proper valve for residential plumbing?
Comment: I have a private well, typically pressurized at around 40-50 psi at the bladder tank
Answer: I often pop the T&P a few times quickly and tap the rod to seat the valve firmly. It works more often than not. Also when you drained your tank, did you open the T&P for relief air? If so, next time don't. I see guys opening it to drain the tank. Then I see guys replacing leaky T&P valves.
Comment: It's just a rubber gasket on a brass seat with a heavy spring pushing on it. Popping it clears some debris on firmly taping the pip in helps to seat the valve deeper hopefully enough to seal fully. The rubber gets hard and tapping it helps to depress it.
Comment: I did not open it, just noticed it dripping. I'll try the toilet jiggle method lol
Answer: When you turned the water back on after your plumbing work you may have mobilized sediment in the tank or lines and this is interfering with the sealing of the TPV. You could briefly open the valve manually with the lever to try to clear it. After doing this it would take a while to see if the leak was stopped.
Of course, it could get stuck open or leak worse. Naturally you'd use a bucket under the relief outlet unless it goes directly into a drain or outside.
Perhaps you should have a new valve on hand when you start dealing with this. You might have to replace the TP relief valve.
Comment: I did try manually clearing it, I also flushed the tank about a month ago in preparation for the bathroom project, of course there could still be residual sediment. I guess it baffled me because I figured the drawdown off the tank when I opened the new valves would reduce the pressure, guess things don't always do what you would assume lol


Which gases increase the greenhouse effect more than carbon dioxide?

Question: Everywhere can be read that carbon dioxide increases greenhouse effect. But there are other gases having worse effect than carbon dioxide, e.g. methane. Is carbon dioxide emission the real threat, or can we fight more effectively against global warming by reducing the emission of other gases?
Answer: No. The worst greenhouse gas is water vapor (H2O). But water is responsible for the natural greenhouse effect.
CO2 is the greenhouse gas with the "least" effect on global warming but with the most quantities available in the atmosphere resulting from anthropogenic influence/sources.
Therefore, all greenhouse gases are compared to CO2, and we talk about CO2-equivalents.

Carbon dioxide equivalent (CDE) and Equivalent carbon dioxide (CO2e) are two related but distinct measures for describing how much global warming a given type and amount of greenhouse gas may cause, using the functionally equivalent amount or concentration of carbon dioxide (CO2) as the reference.

CO2-equivalents for common greenhouse gases:
<code>CO2           1    (Carbon Dioxide)
C3H2F4        4    (2,3,3,3-Tetrafluoropropene)
H2            6    (Hydrogen)
CH4          25    (Methane)
N2O         298    (Nitrous Oxide)
C2H2F4     1430    (1,1,1,2-Tetrafluoroethane)
"CFC"     14400    (Chlorofluorocarbon)
"HFC"     14800    (Haloalkane)
NF3       17200    (Nitrogen trifluoride)
SF6       22800    (Sulfur hexafluoride)
</code>
But to answer your question: CO2 is the real threat to the climate regarding the anthropogenic greenhouse effect. Methane is also very important in global warming, but it's more difficult to say whether methane emissions result from natural or from anthropogenic sources.
Finally: The greenhouse gases with most concentration in the atmosphere:

Water vapor (H2O)
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
Ozone (O3)
Comment: One thing I always think, but never see mentioned in global warming discussions, is something we learn in grade school. Humans intake Oxygen and exhale Carbon Dioxide, and plants reverse the process. Sure, many of our machines are producing CO2 as well, which has contributed to the massive accumulation in the atmosphere. However, humans have removed a very significant portion of the planets natural vegetation, resulting in far lower processing of CO2->O2 than in the past. I think that global warming could be counteracted by aggressively replenishing the forests.
Comment: It's important to note, though, that *clouds* have a complicated relationship to warming, in that they can either hold in heat, or reflect it back into space.  The net effect depends on the kind of cloud, and altitude, basically.  It's also important to note that water vapor is less of a concern because of a natural self-equilibrating effect.  More water in the atmosphere will rain out back to us, and dryer air will increase the rate of evaporation, moistening the air again.  CO2 and CH4 don't have quite the same natural balance point.
Comment: @Prymaldark, that's partially true.  The problem is that the same core reason why we produce so much CO2 / CH4 is the same reason we **can't** easily replenish forests.  There are too many people, using too much space (not just what they live on, but the space for roads, work spaces and farmland to keep a person alive).  Then, there's non-GHG pollution (e.g. acid rain) that affects plant growth.  Some say, if it warms, trees near the equator may die, but will be replaced by trees near the poles.  But, as life hasn't flourished near the poles recently, that soil isn't rich, as trees need.
Comment: @Prymaldark I am not sure that plants would help much. All in all, they have zero net effect - once they die, the carbon re-enters the atmosphere. The problem is all the carbon we brought up from the depths of earth. To counter that, you'd need to bury all the dead plants really deep, to get back at the values of carbon that we had few hundreds years ago.
Answer: Yes, anthropogenic emissions of CO2 are a real threat: the scientific evidence for this is overwhelming. The IPCC summaries provide, every 6 or 7 years, an overview of all the science. The most recent completed one is AR4; AR5 is being finalised now, for publication over 2013-2014. The physical science basis is summarised by IPCC Working Group 1
And yes, some other anthropogenic emissions are, gramme-for-gramme, worse than CO2. Their total levels of emissions are all lower than CO2, and they have different lifetimes, which means that you need to pick a particular time horizon to calculate their relative global warming potential (GWP).
At a 100-year horizon, methane (CH4) is about 34 times as damaging as CO2, weight for weight. Whereas at a 20-year horizon, that factor is about 86.
Water vapour is more prevalent, and has a higher net feedback effect. However, we don't directly change the net amount of water vapour in the atmosphere: it regulates itself very quickly (days to months, rather than the years to centuries that methane and carbon dioxide take), so is considered a feedback rather than a forcing. Warmer air can hold more water vapour, so global warming from other greenhouse gases may increase the warming from water vapour.
To effectively fight catastrophic climate change, we need to cut emissions of carbon dioxide, methane, and the other greenhouse gases: industrialised nations have to cut their annual emissions by about 80% (on a CO2-equivalent basis), and fast (within 2-4 decades, with front-loaded cuts).  That doesn't leave much room for any emissions. So it's about cutting CO2, CH4, N2O, HFC-23, HFC-134a, SF6, and so on.
Comment: Technically and economically pretty straightforward. It's only the politics that's difficult.
Comment: Out of curiosity, how feasible is such an 80% cut, presumably without economic collapse?
Comment: +1 for mentioning the difference in time scales... limiting CO2 emissions is the most effective method for fighting climate change as it's most persistent. Methane emissions will sort themselves out eventually - they are definitely a short-term concern, but long term it's better to address CO2.


Firstborn is sick on erev Pesach

Question: What is the halacha regarding the fast if a firstborn is sick on erev Pesach and can't attend a siyum?
Answer: A sick person might be exempt from the fast.
R Mansour at dailyhalacha writes

Firstborns who are ill or otherwise frail are not required to fast,
  even if they do not attend a "Se'udat Misva."

R Eliezer Melamed, author of Peninei Halacha writes

This fast is less strict than other fasts. All of the other fasts were
  instituted by the Sages, but Ta'anit Bekhorot, a custom adopted by
  many bekhorim, was never instituted as a binding obligation by the
  Sages. It is therefore customary to be lenient. For example, if one
  suffers from a headache, or from a pain in his eye, he is exempt from
  Ta'anit Bekhorot, even though he is not considered sick and would not
  be exempt from other fasts.

Alternatively, following R Ovadia Yosef's opinion that completing a tractate of mishna with commentary is enough for a siyum on Erev Pesach (see 5th comment here or this for more), the sick person could also learn a small tractate of mishna and make a siyum alone, or to get a friend come and do this for the him. Of the smaller masechtot with relevance to Pesach are e.g., Moed Katan with 24 mishnayot or Hagiga with 23.
As everything you read here, ask your local rav for a practical ruling if you want to apply it in practice.
Comment: There is an opinion that eating "targima" (basically non bread non grain) foods will not break the fast of the first born. Sick people, as always, should be evaluated with their health in mind first... iow, how sick are they?

Firstborn is sick on erev Pesach


Why use a hadron collider to search for Higgs Boson

Question: If, according to relativity matter is energy condensed, wouldn't breaking open the endless Matryoshka dolls of matter to find the most fundamental particle which gives mass to matter be fallacious? Fallacious in the sense that searching for a particle composed of energy, energy being something immaterial forming the composition of matter, is searching for something that in itself has no physical existence therefore breaking down particles into sub-particulate matter would go on ad-infinitum because there would be no such "particle" to be found.
Comment: Can you tell us what level of mathematical education you have, so that we can taylor an answer to you.
From your question I would wager that you are not a maths or physics grad.
This question seems more philosophicial then physics as it stands.
Answer: Mass and matter are not the same thing. Matter has mass, as a property, the same way that it can have color or shape. Mass--the property--is a form of energy as dictated by relativity, but matter is not. Energy isn't a substance or "type of stuff" on its own, but a property of stuff. Nothing is composed of energy, the same way they aren't composed of momentum, or blue. So ultimately when you get into the definitions the idea of a particle 'composed of energy' doesn't end up making sense. Particles are often composed of other pieces with smaller energy, but no particle actually is energy.
The Higgs is also not a part of other matter, but the thing that gives matter mass in the first place. Matter is like a ball being pushed through the molasses that is the Higgs field: the Higgs slows particles down and makes them resist movement, which we interpret and measure as mass in the usual sense.
Comment: *"they aren't composed of [] blue"* Depends how gravely their voice is and just how fluidly they can play the slide guitar.
Comment: I just want to say that this is the best explanation of the distinction between matter, mass and energy that I've ever heard.
Answer: To your question,
"Why use a hadron collider to search for a [sic. Higgs Boson] particle?"
It is because the Higgs boson is a quanta of a field, that is particles, the Higgs scalar field (in the Standard Model of Elementary Particle Physics). Colliding high energy particles, such as protons in the case of the LCH at CERN, allows one to produce quanta of the fields in the universe.
As regards your question
"Wouldnt breaking open the endless "russian dolls" of matter to find the most fundamental particle which gives mass to matter be fallacious?"
No, it would not. You need to read up and understand how the Brout-Englert-Higgs Mechanism works.
Long story short, a complex-valued scalar field, $\phi$, say, which transforms as a doublet under $\mbox{SU}(2)$ transformations has interactions with the $\mbox{SU}(2)$ Yang-Mills fields of the Standard Model. When we choose a certain gauge, called the unitary gauge, the vacuum-expectation-value of this $\phi$ field gives what we call a mass term for the other fields in the thoery.
It it NOT the case that the other fundamental fermonic and bosonic fields of the theory are somehow 'composed' of this $\phi$ field.
Comment: @krue.ron.taiepa : P.S. referring to the quanta of Higgs field as a diety is considered offensive to some peoples ears.
Answer: I think you have a really interesting question there, but you are starting with a slight misunderstanding about matter and energy.
It is certainly true that matter and energy are basically the same thing, and indeed when calculating the curvature of spacetime in general relativity we don't distinguish between them. However that doesn't mean we can make particles with any mass you like. For example there are lots of electrons with the same mass $m_e$, but no particles with a mass of $1.1m_e$ or $0.9m_e$. So you're wrong to suppose that as we go to higher and higher collider energies we'll keep breaking down particles ad infinitum.
To understand why this is, and incidentally why finding the Higgs mattered so much, you need to understand what a particle is. I discussed this in my answer to What keeps mass from turning into energy?, and you might want to have a look at that before proceded any further. In brief, a particle is an excitation in a quantum field. You create a particle by adding energy to a quantum field, but because the fields are quantised you can only add energy in chunks of a fixed size, with each chunk corresponding to one particle. So add one hunk of energy to the electron quantum field and you create an electron, add two chunks and you create two electrons and so on. Likewise, take a chunk of energy out of the field and you destroy an electron.
So the next question is why can't I have a quantum field that takes chunks of energy corresponding to $1.1m_e$, or $0.9m_e$ or any energy I want so I can make particles with those masses? Well that's because the quantum fields are all related to each other by a type of symmetry called local gauge symmetry, and this only permits a certain number of fields to exist. You can't just throw in any field you want because it wouldn't fit with the requirements of the symmetry.
And now we come to why finding the Higgs was so important.
Prior to finding the Higgs we had an established theory called the Standard Model, which is based on the local gauge symmetry I mentioned above. This theory predicts all the particles we see, like electrons, protons, etc, but it also predicted a Higgs boson must exist. So if we managed to find a Higgs this would neatly complete the theory and show it must be true. On the other hand failing to find the Higgs would lead to us having to question whether the Standard Model was the correct theory or whether we had all been barking up the wrong tree. Fortunately we did find the Higgs, so we can all sleep easily knowing that the Standard Model is correct.
Answer:
Fallacious in the sense that searching for a particle composed of energy, energy being something immaterial forming the composition of matter,

Your concept of energy is fallacious, i.e wrong and leading you to wrong conclusions
Energy is very well defined macroscopically, with the classical mechanics mathematical theories and the electromagnetic theories, and thermodynamics. In these classical frameworks energy and matter are two differently defined quantities. Masses have energy, electromagnetic fields have energy , energy does not have mass.
Atomic theory introduced a need to enlarge the concept of energy, and as smaller accelerators than the LHC  found out for subatomic particles, classical mechanics had to be modified with the special relativity formulation in order for  theoretical models to fit the data. In addition Quantum Mechanics was established as the theory of the underlying level of nature.
The famous E=mc**2 must be what has led you astray. The m there is the relativistic mass, but energy mass relation for  elementary particles  is written as :

rest mass in units of c=1

m is an invariant of the relativistic transformations, and called "the rest mass" that characterizes each particle uniquely, in the particles table:

Elementary particles included in the Standard Mode

is searching for something that in itself has no physical existence

So masses, and the particle quantum numbers, have a physical existence, contrary to your statement, that we detect with our experiments in accelerators, including the LHC.

therefore breaking down particles into sub-particulate matter would go on ad-infinitum because there would be no such "particle" to be found.

No, this is wrong, starting, as I stated above, from wrong premises. It may be possible and people are searching for compositeness, i.e. that what we consider elementary particles now may be composed by smaller "preons", but this does not invalidate the particle table, as the existence of the particles in the table did not invalidate the periodic table of elements. So nested matriouskas, might be in the future, but not in the random manner you are fearing or describing.
Answer: Particle colliders are not being used to search for one single particle of which everything else is composed.  According to the Standard Model there are multiple particles that are considered elementary.
The phrase "G*d particle" is slang for the Higgs Boson, which has been recently confirmed to exist.  However, the other elementary particles are not composed of Higgs Bosons.
Particles have many other properties beside their mass/energy, such as charge, spin and lifetime.  It is important to understand what particles exist and their properties, to have a complete theory of physics.


Can I submit the same article, which is written in two different languages, to two different journals simultaneously?

Question: I have written an article in Persian and then translated it into English. Is it possible to send them to two different journals (one in Iran and the other one in Belgium)?
Comment: AFAIK, the language doesn't matter, it would still be "double" publishing or self-plagiarism. There are journals that accept it in that condition, but I do not think it is the rule...
Comment: @Alexandros: maybe it will offer the possibility to Iranians that does not speak English well to understand the content of the article? Not everybody can speak English
Comment: Do not do it. Plain and simple. If this is a good publication, what will it offer you being published in Iranian? If it is not,  2 or 100 copies of the same paper will not do you any good.
Comment: @Taladris: that's a good point, but it is served just as well by making the Persian version publicly available online in some other way (e.g. through the author's website, or a preprint server).  Printed journals are no longer the only means of public dissemination, and in many fields, are no longer the main one.
Comment: This is plagiarism at worst, double submission at best: in any case it would be shady.
Comment: what is the content of the work?  in some cases, the process of translation itself would alter the work somewhat -- i.e., certain ideas would not be identical in the two languages -- making double publication sensible.  and i agree with @Taladris that there is good reason for publishing even the exact same work in two languages.  however, in order to make that less shady, i think you should have a note in each publication mentioning that it has been published in the other language and giving the citation.
Comment: @Taladris That is cause for submitting a translation and making it clear it is, *not* a simultaneous submission
Comment: It is about ancient history.
Answer: Yes, this is a problem. You should not submit the same work to more than one journal at a time. This applies regardless of language - merely being in a different language does not make the actual work unique.
Further, consider some practical considerations - a simultaneous submission means that you'll have to go through peer-review for both papers and (assuming you don't get caught and summarily rejected) presumably have to make some changes. What if the changes don't align? Now you don't have two translations of the same paper, but two subtly different papers in two languages.
If you're genuinely interested in making your paper more accessible, either post a translation online, or wait until one paper is accepted and then approach a journal in the other language about posting a translation.
Comment: @ÉbeIsaac A translation of a published article is *substantially* different from a simultaneous submission, which is the question.
Comment: @ÉbeIsaac An example: "The American Journal of Epidemiology considers manuscripts for which copyright has not been assigned, that do not essentially duplicate already published material, and are not being simultaneously considered for publication elsewhere." You will note no exception for language.
Comment: @ÉbeIsaac: By making simultaneous submissions as you describe, you are presenting both versions as independent original work — that's the self-plagiarism/double publication.  If you publish one version, and afterwards submit the other, clearly described as a translation of the first, then this would be fine, and analogous to the examples you mention.
Comment: Could you cite the rule which includes the line *"regardless of the language"*?
Comment: If no specification exists, how could you claim that it isn't allowed. There is proof that it is possible as historical articles of different languages have been published in various languages. Are they all guilty of plagiarism and double publication?
Comment: @PLL: True and that is what I've included in my answer too.
Answer: If you write an article in Persian, you have the legal right to translate it to English, as long as you haven't assigned the copyright to someone else (in which case, you have to obtain the right to create a derivative work from the copyright owner). Many journals require you to assign copyright when they publish an article, and require you to avow that you (still) have the right to assign that copyright. So if you have assigned the right to make copies (including translations) to one journal, you can't then truthfully vow to the other journal that you can assign the right to the derivative work in English.
Journals have two basic reasons for following a no double publishing rule. One is the aforementioned copyright problem, that it might put one journal in a bind with respect to copyright. If neither journal requires copyright assignment and only requires a non-exclusive license, then the second reason may also be applicable, which is that journals consider their space to be a valuable commodity, to be used only when there is sufficient justification. Basic academic quality is one reason, but novelty is another -- a journal's editor could well decide that it is not worthwhile to use journal space to publish a paper that has already been published.
Since this is a matter of editorial judgment, the solution is simply to ask each editor whether it is okay for you to also submit a version in the other language. If both editors agree (and assuming that you have stated the facts clearly enough), then there would be nothing problematic with submitting a version of a paper in Farsi to one journal and a version in English to another journal. Versions in French and English would be more problematic, because there is a reasonable expectation that scholars can read both languages, whereas there are relatively few areas where scholars are standardly expected to read both English and Farsi, and providing an English translation could be a significant contribution.
So, to repeat, ask the editors.
Comment: I don't claim that anyone expects bilingualism, just that (depending on the field) a reading knowledge of French, or German, is normal, and often a forma; requirement for graduation.
Comment: I think this is the correct answer. I've done exactly what's being suggested here. I had one paper in my native language accepted, and I got permission from the editor to publish the same article in English. I then asked the editors of a couple of international journals if they would accept an English translation of my article. One journal said no, the other said yes (incidentally the top journal in the field), as long as the article made it perfectly clear how it related to the other article. Case closed (the final version ended up being a new paper, but that's a different story).
Comment: "Reasonable expectation" implies far more than just "sometimes this happens in some fields"
Comment: "because there is a reasonable expectation that scholars can read both languages"????
Comment: @user6726 They're contesting that French-English bilingualism is common enough for your expectation to be reasonable.
Comment: This is a important experience and because of it I removed the acceptance tag from Fomite's answer.
Comment: Yes, is that idea unfamiliar to you?
Comment: @Sverre Again, submitting a *translated* version of an already accepted/published article is vastly different than a simultaneous submission of the two. The end result is the same, but process matters. For example, "as long as the article made it perfectly clear how it related to the other article" is impossible with simultaneous submissions.
Comment: I lied - the end result isn't even the same. See the edit to my answer re: peer review and revisions. Simultaneous submissions are just a bad idea.
Answer: Publishing the same manuscript in more than one journal at a time is technically double submission. But this wouldn't be so if you consider one as a translated version of the other after one is published as long as you make this explicitly clear in the second paper. It isn't ethically wrong to publish your research in different language as it increases the visibility of your research in the right sense.
Comment: In this case you shouldn't just cite the already published paper; you should make it absolutely clear that the second paper is a translation of the first (e.g. in a footnote on the first page).
Comment: Yes, that is my point, @PeteL.Clark.
Answer: I do not recommend it, for the following reasons:
Firstly, because the same ideas and results will appear on two different papers, and someone that wants to credit your findings (and reads both languages) doesn't know which paper to cite.
Secondly, if I would see your Iranian paper (in journal X) cited on paper Y but I would only know the English version of it (in journal Z), I would have to check that they are, in fact, the same scientific result.
Finally, in most journals publications are required to present new results. Pushing your case to the edge, I could write 2 papers in English: one in such a way that only a native speaker would understand, and another that my community would understand. This is not acceptable by most journals.
There are exceptions on which publishing the same results is acceptable, for instance, some journals do not require the results to be new. In this situation, I don't see the issue.