How might an organism that is made from neutron superfluid store genetic information?

Question: I was thinking of a set of life forms that originates from neutron superfluid inside a neutron star.  So these life forms are not made of atoms but are made entirely of neutrons.  How might this life store genetic information and how might it copy this genetic information?
Comment: This is an interesting question. Unfortunately, it deals with highly speculative physics. Perhaps you should look at Robert Forward's DRAGON'S EGG, for life on a neutron star, and Stephen Baxter's FLUX for life inside a neutron star. Though I doubt if they went into the nitty-gritty of the mechanics of neutronic biological reproduction. My guess is we don't know. Almost makes me wish we did.
Comment: Robert Forward wrote an article "When you live upon a star ..."  about life on neutron stars in NEW SCIENTIST, 24/31 December 1987, pages 36-38. That would be a good place to start.
Comment: Also, Frank Drake wrote "Life on a Neutron Star," Astronomy, p. 5, December 1973. Robert Forward apparently began with Drake's ideas for neutron star based life and expanded on them.
Answer: The simplest answer is the Wikipedia article on Robert Forward's Dragon's Egg which has this information culled from the novel.

Around 3000 BC Dragon's Egg cools enough to allow a stable equivalent of "chemistry", in which "compounds" are constructed of nuclei bound by the strong force, rather than of Earth's atoms bound by the electromagnetic force. As the star's chemical processes are about one million times faster than Earth's, self-replicating "molecules" appear shortly and life begins on the star. As the star continues to cool, more complex life evolves, until plant-like organisms appear around 1000 BC. One lineage of these later became the first "animals", the earliest of these stealing seedpods from sessile organisms and some later lineages becoming predators.[3]

There you go, the nuclear equivalent of chemistry and by assuming everything else common to chemistry leading to biochemistry and molecular biology, and by analogy, life. This works for science-fiction, but in the real cosmos who knows?


Cellular Automata: Does there exist an initial group of cells in a square lattice which never zeroes out completely?

Question: Fix a positive integer $k$.
Given an infinite grid of squares, each of them is assigned a nonnegative integer value. Furthermore, only finitely many of these values are nonzero. Call this state Generation $0$. In Generation $n+1$, a cell is given the value:

$0$ if the sum of its four neighbors in Generation $n$ was not divisible by $k$;
$\frac{1}{k}*\text{(The sum of its four neighbors in Generation n)}$ otherwise.

The question is this: Does there exist an initial configuration such that the grid does not eventually become all zeroes?
For $k\ge 4$, the answer is easily no; one can prove this using the sum of all the grid's numbers as a monovariant. For $k\le 2$, the answer is easily yes; for $k=2$ consider two diagonally adjacent "$1$"s. But what about $k=3$??
A similar question can be posed for a hexagonal grid (considering six instead of four neighbors). Here, it is yes for $k\ge 6$ and no for $k\le 3$. But what about $k=4, 5$??
Sidenote: These questions arose when I was fooling around with numbers on graph paper the other day, and I have no idea whether they are solved or open, known or new. Heuristically, it seems that every square configuration should die out for $k=3$, as the sum of all entries will, on average, multiply by $\frac{4}{9}$ after each generation. But there might also exist some extraordinary initial configuration which results in infinite expansion.
Example: The picture below shows a sample when $k=3$ on a square grid (only nonzero entries shown). The grid would die out after Generation 2.

Edit: fixed a typo; now things should be clear.
Comment: You have not said what the fixed integer $k$ has to do with the automaton.
Comment: I have fixed the typo, things should make sense now.
Comment: You are using $4$ neighbours, not $8$, it seems?
Answer: For $k=4$, a checkerboard pattern of 1's does not die out.
For $k=3$, the honeycomb pattern does not die out.


Is a square a special case of a diamond (rhombus)?

Question:
Is the diamond shape (rhombus) necessarily different from the square (sides not perpendicular, different lengths of the diagonals), or is the square a special case of a diamond?

Sometimes I see a square (with right angles) that is called a diamond just because of being rotated by 45 degrees from the position where two of the sides were horizontal and the other two vertical, but I doubt that just this rotation (which is an isometric transformation, without any deformation) is sufficient for the square to become another shape.
Comment: write your logical definitions of each then see which one also satisfies the other
Comment: At the end, the square is a special case of (nearly) any quadrilateral.
Answer: Mathematically speaking, something is called a rhombus, when it has four courners and all edges have the same length.
Something is called a square, when it has four courners, all edges have the same length and the four interior angles are $90°$.
So yes, a square is a special case of a rhombus.
Answer: The standard terminology in plane geometry (if the English language even has one) is that a square is a rhombus which is also a rectangle; equivalently, in a more exhotic and minimalistic way, a kite which is also a rectangle. Of course plane geometry is invariant by the action of the group of plane isometries, and therefore it isn't concerned with the graphical rendering of a square in an "organized" space where one or more directions are more important than the others.


What is the optimal temperature for PLA+?

Question: I'm planning on switching to using PLA+ and am slicing a few models, I'm wondering what the typical optimal temperature for PLA+ is with the Ender 3.
Comment: AFAIK every manufacturer has some suggested temperatures for their products. Beside of that the temperature you are printing with depends on your local setup. So it is a good idea to make some testprints with new filament. Print a temp tower and see which temparture performs best for yours.
Comment: There are multiple formulations for PLA+ and you have not specified a manufacturer, so we don't have enough information to give a specific answer that isn't a guess.
Comment: [What is PLA+? How is it different from PLA?](https://3dprinting.stackexchange.com/questions/4982/what-is-pla-how-is-it-different-from-pla)
Answer: Usually the filament spool will have a range of temperatures for the best nozzle temperatures and bed temperatures to use.  To answer your quesstion there are several considerations.

Not all PLA's are the same and that is probably even more so with PLA+.  That is where the temperatures written on the spool come in handy.

Optimum temperatures will vary for different printers.

Optimum temperatures will vary depending on the print job: large versus small; thick versus thin; short verses long; etc.

Optimum temperature will vary depending on print speed, as well as enclosure or lack of, and air circulating through enclosure with fans.

You may need to tweak settings to get the optimum print.
Comment: Also note that filament vendor's temperature ranges are usually specified assuming you're printing at snail speed. If you'll be going significantly faster you probably need to increase them. This isn't just compensation for an underpowered hotend not keeping up (which can be an issue) but for the heat that needs to be transferred to the previous layer to get the new one to bond to it, which can be reached at low speeds just by having the nozzle dwell in the vicinity for a long time but needs a hot nozzle at high speeds.
Comment: @R. I thought about this with 3, but it really belongs separate thus 4.


What would the typical damage of a person creating propulsion on themselves and then use that momentum to punch someone be?

Question: Lets say a character can create magic propulsion to push themselves, fly, and move quickly. And then this character uses this speed and momentum to punch someone. At what speed would the user begin to take damage from doing such a punch like breaking their bones.
Comment: Sorry, he can fly? And he wants to punch somebody? Drop a brick on his head!
Comment: Sorry about that, the [site went down for a while, among others](https://meta.stackexchange.com/questions/375995/some-sites-offline-no-blog-or-twitter-info-is-all-ok).
Answer: Figure out damage at speed by the speed of an equivalent free fall.

You could figure it out.  Figure out how fast your character is going when he hits.  Then figure out how far one would need to fall to be going that fast using the fall calculator.  https://www.omnicalculator.com/physics/free-fall
Then plot what sort of damage is done using the graph which I took from here:
Fall from heights: does height really matter?
-
I think it is safe to say that going faster than 15 mph will break a bone on impact.  Whether it is your hand or your hand and arm, or hand arm and shoulder depends on how fast you are going.
When I am flying in to give someone a whack I am going to be holding a rubber chicken, and holding it loosely.  That equal and opposite reaction is no fun at all.
Answer: In a bare knuckle fight, which I assuming is the premise, punching someone in the head is more likely to break your hand than their head. Even with a lot of  training applying a closed fist to the bony structures of the face often results in broken and dislocated knuckles and bones in the hand, no extra momentum need be applied. In my personal experience most of the training in martial arts that I have received, whether it be boxing, Ju Jitsu, or Kung Fu focuses on not hitting people in ways that expose the bones of the hands and feet to solid impacts on the bones of your opponent. I would imagine that you risk breaking bones on the softer targets, like the stomach and solar plexus, in much the same way that one will mangle themselves punching someone in the head if the impact speed were increased by two thirds to double, i.e. if the person throwing that "punch" were traveling 25-30mph and plowed an upraised fist into their target.
Answer: If they're unarmed?  Zero.  As mentioned elsewhere, if you punch someone in the head, you're more likely to break your hand (this is actually what boxing gloves are for - protecting the wearer's hands).  If you can fly and want to hurt someone, just drop a rock on them.
If they're armed, though, it's a different story.  A blunt weapon probably has the lowest speed limit - above some speed, the impact force will jar it out of your hands.  Professional baseball players can hit 150km/h fastballs with no trouble.  But baseballs are designed to be easy to hit, and are so light they offer very little inertial resistance - more massive targets, like someone's head, would be much tougher (if you want a ballpark, picture using a baseball bat to hit a baseball, a soccer ball, and a stop sign).
One solution is to make the blunt weapon heavier.  This way, you do most of the work by accelerating up to speed - when you hit, you aren't swinging the weapon so much as you are traveling next to a large, heavy object that happens to have a handle you're holding on to.  For example, a car hitting a human at highway speeds will have a much greater inertial effect on the human than the human will have on it.  If this character can use his magic propulsion to lift very heavy objects, they could just throw a car at their target... but then they wouldn't really need to be anywhere near what they were throwing.  So the maximum speed and thus power of a blunt weapon strike will be determined by how much they can lift and carry with them.
But if you really want to hurt someone by moving fast, you want an edge.  Literally.
Bladed weapons bypass the impact force limitation, because they don't care about impact force - in fact, less force is usually better.  With a reasonably sharp blade, you only need a few pounds of force to cut skin.  Contrary to what Errol Flynn's filmography would suggest, most fights involving bladed weapons are over very quickly - even a glancing blow can cut enough to be quickly fatal.  If your flying character has a sword - or even a knife - they wouldn't need to be moving very fast to kill or seriously injure their target.
The downside of blades, of course, is that they are much less effective if the target is wearing any kind of armor.  Some armor has gaps or limits that a well-aimed sword strike can get around, but if the target is wearing something equivalent to a full suit of plate, then you're going to be out of luck.  In this case, your character would be back to blunt weapons.  Many works focus on piercing weapons (such as lances or war picks) as a means of defeating armor, but those would be much less useful for your flying character - it would tend to get stuck in the target and yanked out of their hands.
In conclusion: Bypass the problem with swords and/or dropped rocks.


Is a password really necessary?

Question: For the purposes of security, is there any difference in having a 50 character randomly-generated secret username accompanied by a 50 character randomly-generated secret password, versus a 100 character randomly-generated secret username with no password?
Comment: The "secret username" might not be feasible. Does that matter in your scenario?
Comment: Possible duplicate of [Why do we authenticate by prompting a user to enter both username and password? Does prompting the password only suffice?](https://security.stackexchange.com/questions/2384/why-do-we-authenticate-by-prompting-a-user-to-enter-both-username-and-password)
Comment: a [related](https://security.stackexchange.com/questions/58215/are-random-urls-a-safe-way-to-protect-profile-photos) question.
Comment: @Arminius Thank you for the feedback. I updated the question for you.
Comment: @schroeder Thanks.  In this scenario, no it doesn't.  But good question.
Answer: I think it depends on how you define "username".
Usually a username is something that is derived from the name of the user.
So it is guessable.
A username is often displayed in the Application at some kind of user preferences. So the username is visable.
Then a username is sometimes used to reset a password, and thus the username might be sent over the wire - maybe via smtp. So the username can be fetched from the traffic.
Sometimes users need to communicate to each other - so the username becomes a public data.
However, if you think of some kind of authorization token as a username, you could very well take a 100 characters long "string" to authenticate. But do not think of that as a "username"!
Comment: You are right. And if you do not draw this line, then you should not call it "username". He is maybe thhinkg of a kind of "service account". And in fact he could use a 100 byte string auth token instead of a service account. But there would be no "username" involved.
Comment: I agree, a "username" is an identifier, so it should be a public data, then you need somethind to be sure that someone is owner of that identifier, in this case a password, they are different things for different purposes.
Comment: In some systems, for example [here](https://www.vaultproject.io/docs/auth/approle.html) credentials are two guids, one serves, as application id and the other as the secret. In this case it's not really visible or guessable. Here, using the pair, as I understand, is not used to increase *security*, just to make secrets management more convenient (like an ability to have several passwords, or more obvious way of linking credentials to the entity they protect)
Comment: It's probably more accurate to assume OP is talking about a user login (which many sites do call a username, even some that literally just make it your email address). You can have a display name on top of that. "Name" just means how "a person or thing is known, addressed, or referred to", which can certainly include the string you're using to log in with. That assumption would largely invalidate your answer. This assumption seems more likely considering that OP said the username is secret.
Answer: The main disadvantage of a single "token" (or "username") to authenticate is that in order to authenticate the user you have to do one of two things:

Store the token in the database in a retrievable form such as plain text or encrypted. This means if the DB is compromised the attacker will know everyone's token.
Hash the token. But if you do this it's best to use unique salts per user, but in this case you can't. You would have to use the same salt for every hash, which opens the door for rainbow table attacks.
Answer: You're combining two concepts, identity and authentication, into a single entity.  You are then calling the result "username".  This name incorrectly implies to the reader that it's only embodying identity, hiding the fact that it should be kept secret to secure the authentication aspect of it.  Remember that identity is not normally something people keep a secret.
"Unguessability" is an important attribute of a secret used for authentication.  But security doesn't come only from having an unguessable secret.  It also comes from people properly handling that secret.  By calling it something it's not, you risk confusing your users into treating this secret like they would their email address.
This is not a theoretical problem -- it's the foundation of all the problems with credit card theft the world suffers from today.  Credit card numbers were always associated with identity, not authentication, but they serve both purposes making them valuable to thieves.
To avoid this problem, I would not call the 100 character string either a "username" or a "password";  instead, calling it a "token" might help people understand how to handle it.
Answer: The most important aspect to passwords is secrecy. If a username is completely secret from everyone but the user, then you don't need a password. If a username is ever shared with anyone else, then you do.
Additionally, having a secret username would be a UX nightmare - people don't expect usernames to be secret, and won't treat them as such.
Answer: If by "username" you mean an auto-generated long account identifier not visible to other users, and where an email/username is not needed for account recovery, it can make sense.  Examples would be Resilio/BitTorrent Sync "indentities" or cryptocurrency private keys.  For the purposes of this answer we'll call this secret the "password," not the "username."
In fact if some service allows the public username to be used (along with a password) to authenticate, then it's essentially already using just the one secret, the password, to authenticate.
If you have just one single password for authentication, what happens if a user attempts to use a password someone is already using?  You can't warn the user that "that password is already taken."  To avoid this scenario, the app itself would have to generate the long and unique password, and in turn this would most likely mandate the use of a password manager.
Another problem is account recovery -- you may need the user to associate their email with their account anyway to allow the password to be reset.  If this is the case you might as well use both a username and password to log in.

Is a password really necessary?


Infeasibility in mathematical optimization models

Question: Sometimes, when solving mathematical optimization models (especially MIPs), they may be infeasible.  Is there any comprehensive method to deal with the infeasibility conditions? (especially in complex models)
Comment: Maybe you should clarify: is the problem really  infeasible (so you want a good solution as close as possible to feasibility, as in many practical cases), or the model is buggy and you want to correct it? In both cases, adding penalties through slack variables can help.
Comment: @Matteo Fischetti, Kevin Dalmeijer, Dipayan Banerjee, EhsanK, Geoffrey Brent, Oguz Toragay, Many thanks for all the useful answers.

Please, let me know how we could figure out the causes of the infeasibility before solving the model? Is there any way?
Comment: Without specific problem knowledge, I think the most practical way to detect infeasibility is to just start solving the model. Why are you interested in a different way?
Comment: I have a similar problem. While I understand all of these methods helps us to figure out the source of infeasibility (the possible constraint causing infeasibility), are these automated? Can I run my optimization model and then if it turns out infeasible run some mechanism to check for the exact constraint causing infeasibility? I also have a follow up which is most imp - suppose I am able to figure out that constraint...now that constraint is further formed using n number of inputs. How do I figure out further which exact input caused this infeasibility? Any help would be greatly appreciated!
Comment: @KajalChanchalani, as an automated approach many modern solvers have a capability to detect infeasibility that named IIS method. But the best is by investigating the minimum instances by hand to make sure whats really happened and how you turn out that to a feasible one.
Answer: Adding slack variables (with high penalty in the objective function) converts hard constraint into soft ones, and can also be useful to locate the source of infeasibility. This approach can be very useful for feasible problems for which finding a heuristic feasible solution is hard/very time consuming.
Comment: I would like to add a word of warning. If choose a HUGE penalty instead of reasonable you easily creates numerical problems. This is very common issue I think all solve guys/girls have seen.
Answer: Some methods I've used - most of these have already been discussed in other answers, but I wanted to elaborate a little on these. Ordered roughly in the order that I would try to apply these, which is of course influenced by the kind of problems that I work on.
1. Confirm specification of constraints by testing against a "known feasible" solution (as mentioned by @EhsanK).
In my own experience, and in almost every OR project I've heard about from other practitioners, it's very unusual that clients will be able to specify the rules perfectly on their first attempt. It's just a very difficult thing to do, especially for people who aren't familiar with OR programming. Sometimes you'll find that rules presented as hard constraints are actually soft constraints, or have exceptions that haven't been included in the specs.
If your client is able to provide an example of what they consider to be a satisfactory solution, testing it against your understanding of the rules is a very effective way to discover misunderstandings and mis-specifications.
As well as being pretty straightforward to code (assuming that your client can provide an example of a feasible solution), this approach is often easy to communicate to clients. If I produce an IIS and discover that the problem lies somewhere in this set of $500$ constraints, that will be very hard for clients to interpret. If I can say "hi, this example solution that you gave me breaks this rule that you said I needed to include, what gives?" that's a lot easier for the client to understand and address.
2. Build up the model one rule at a time and test as often as possible.
This is a good idea in almost any area of programming. The faster you detect new bugs, the easier it is to figure out the causes.
3. Eyeball infeasibility diagnostics and look for obvious matches in inputs.
I mostly work via AMPL. When it detects infeasibility in presolve, it will usually give information on the size of that infeasibility - "upper bound $-67$, lower bound $0$" sort of thing. Quite often I can find the cause of the infeasibility by scanning the inputs for values that match the size of that gap; for instance, I might have a value that has been constrained to be non-positive but also to be equal to $67$.
This is by no means a foolproof approach, but it's quick and easy to do, so I'll often give it a try before going to more systematic methods.
4. Ersatz/manual IIS methods
Experiment with switching off constraints selectively and attempting solves, to figure out which rules are incompatible with one another. Again, this is not as systematic as using proper IIS methods, but it's often easier to do/interpret, and it can be used with solvers that don't have IIS capability.
5. Automated IIS methods (as mentioned by @dxb and @KevinDalmeijer).
Some solvers have the capability to automatically identify a set of conflicting constraints. This is a useful capability but I tend to de-prioritise it because much of my experience has been with problems where the IIS's tend to be large and tedious to interpret, so I like to try other methods first. YMMV.
When I do use this approach, if I have a large IIS, I try to look for commonalities between the constraints - for instance, if my variables are indexed $i,j,k$ and the IIS constraints have different values for $i$ and $k$ but all have the same $j$-value, that's probably where I want to look first.
Note: some products can get in the way of IIS methods. For instance, when I use Gurobi via AMPL, it's possible that AMPL presolve will detect an infeasibility before it ever passes the problem to Gurobi. In this case, I can't use Gurobi's IIS capability because Gurobi never sees the problem. The solution here is to switch off presolve.
6. Slack methods (as mentioned by @MatteoFischetti).
One thing I'd add to Matteo's advice is that the shape of the penalty function will affect the information that you get from this approach.
Suppose I have a system of constraints like:
\begin{align}C_1&: x \le 5\\C_2&: y \le 5\\C_3&: x+y \ge 13\\&\cdots\end{align}
If my penalty function is linear, then most likely the solution I get will only use slack from one of these three constraints, e.g. $x=8$, $y=5$. Looking at the results, I can then see that $C_1$ is involved in the infeasibility, but I can't easily tell what else is involved.
If my penalty function is quadratic, OTOH, then I will usually get a solution that uses slack from all constraints involved in the infeasibility. In this case, if I weight all three slack variables equally - and if I switch off the non-penalty components of the objective function - I will get the solution $x=6$, $y=6$, which violates each of the constraints by exactly 1. This makes it much easier to see all the constraints involved in the infeasibility by scanning the slack values. It can even help to identify and distinguish multiple groups of incompatible constraints in a single run - e.g. if I have three constraints that end up with a slack value of $1.33333$ and two others that end up with slack of $2.5$, these probably form two separate groups of incompatible constraints, something that I can't identify from an IIS method without multiple runs.
Obviously this requires that you have a solver that can handle quadratic objectives, or alternately that you construct a piecewise linear approximation to a quadratic penalty function.
This can be quite a nice method; I only put it below the others because it's a little bit more work to program.
Comment: Is there is something similar the the sixth method but when using metaheuristics instead of solvers?
Comment: @JoffreyL. Not that I know of, but that doesn't mean it doesn't exist. (And sorry for the slow reply, I don't check in much here these days.)
Answer: CPLEX offers the conflict refiner for this purpose:

A conflict is a set of mutually contradictory constraints and bounds within a model. Given an infeasible model, IBM ILOG CPLEX can identify conflicting constraints and bounds within it. CPLEX refines an infeasible model by examining elements that can be removed from the conflict to arrive at a minimal conflict. A conflict smaller than the full model may make it easier for the user to analyze the source of infeasibilities in the original model.

Taken from the CPLEX documentation.
Answer: On top of getting IIS from the solver and using slack variables (as suggested by other answers), one more thing that you can do for debugging purposes is to fix your variables to a known feasible solution and see what is reported from your model. Doing that, you can figure out what has happened to make the problem infeasible.
For example, assume you have $x_1 +x_2 = 10$ constraint and a known feasible solution is $x_1 = 6, x_2 = 2$, you can see the infeasibility and the constraint that throws the infeasibility.
Comment: This is one of the best ways. I did it too.
Answer: Related to @Kevin Dalmeijer's answer, Gurobi offers Irreducible Inconsistent Subsystem functionality via Model.computeIIS():

Compute an Irreducible Inconsistent Subsystem (IIS). An IIS is a subset of the constraints and variable bounds with the following properties:

the subsystem represented by the IIS is infeasible, and

if any of the constraints or bounds of the IIS is removed, the subsystem becomes feasible.

Note that an infeasible model may have multiple IISs. The one returned by Gurobi is not necessarily the one with minimum cardinality; there may exist others with fewer constraints or bounds.
Answer: Here is a good (but a little bit old) paper1 discussing the algorithmic approaches to identify and manage the infeasibility situation in MIPs and IPs.

 Reference
 [1] Guieu, Olivier, and John W. Chinneck. "Analyzing infeasible mixed-integer and integer linear programs." INFORMS Journal on Computing 11.1 (1999): 63-77.


Would like some clarification on screen resolutions

Question: While working on a website, I asked a friend what his monitor size was. He said his monitor was 32" but added that the size of the screen does not matter in web design, It's the resolution and that "It's fairly safe to say now that everything ought to look good from 1080p down to mobile browsers". I've been using tools like http://quirktools.com/screenfly which has lists of monitor sizes along with resolutions. The monitor drop down with the list of monitor sizes confused me a little because I thought for example where you can select 10" 1024 X 600, I thought the 10" meant that 1024 X 600 was typical of 10" monitors so asking my friend what monitor size he had would give me a good idea of what his viewing experience might be like thinking there are typical resolutions for screen sizes. Was I wrong? Also, how would you design to also accommodate such large screens?
Comment: "see the site the way I would want it to be seen" = that's not how web design works. You can't dictate how they see your site, you can merely suggest what how they see your site. Always remember that the end-user has a lot of say in how they look at your site, so try to accomodate that when you can (such as making sure the site works on a wide variety of browser sizes.)
Comment: Also, completely ignore the physical measurements of the monitor. a) they are irrelevant as the number of pixels are what is important b) most monitors can be set to different resolutions c) it's no the screen size as much as the browser size that's important (which can be pretty much any size)
Comment: Hi Brandon, welcome to UX.se! I am not able to understand your question. Do you want a rule of thumb for screen resolution you should be designing for? Or, do you want to know how to design for large screen displays?
Comment: I wanted to know if asking my friend what his monitor size was, was a bad way of determining whether or not he'd be able to see the site the way I would want it to be seen assuming that a 32" monitor would have a resolution far greater than any I've designed for with media queries. In addition, I'd like to know how to design to accommodate such large screens.
Comment: Look at this question http://ux.stackexchange.com/questions/6929/common-screen-resolution for common screen resolution. And unless you are designing for television or wall displays, you do not need to design for bigger displays individually.
Comment: Is a monitor size such as a 32" monitor indicative of a typical resolution 32" monitors might have?
Comment: You can assume 2560x1600 for super HD and 1980x1080 for HD.
Answer: Short answer - yes you are wrong. There isn't a good relation between the physical size of a display and the resolution of that display.
For example - iPhones 4S has the same physical screen size as an iPhone 3 - but double the resolution.
In turn there isn't a good relation between the resolution of a display, and the amount of screen you have available within a browser. Not everybody browses with windows maximised - especially on large displays.
You can maybe extract some rough rules of thumb - but they're going to be wrong a lot.
I'd have a google around terms like "responsive web design" - they'll give you some pointers on how you can approach designing for different resolutions.


how to work create virtual table in sqlite and access?

Question: I am working with sqlite in iphone application. what i want to do is like i will get the data from data base using "select * from tablename". but i don't want to access all the rows at a time. I know that we can use cursor for this. I know how to write them in MySql procedures. but I want it to be implemented in my app. [Virtual table]http://www.sqlite.org/vtab.html#xconnect here they explained like we have to create  virtual table to use cursor. so if any body worked with this can you explain me how to do that with some coding example...
Answer: I believe you're trying too hard. SQLite only fetches one row at a time. There is a function call that will obtain all the rows, but the documentation specifically states what it is doing.


Should a bushing or sealant be used when bolting a gun safe to the cab floor?

Question: The Nissan Titan quad cab has a rear seat fold up which when moved up shows a visible compartment for storage.  I would like to remove this plastic compartment and install a custom gun safe but I am unsure how to properly secure it to the cab.  To prevent leakage or any weather related material coming through the holes on the bottom of the cab what is the strongest solution I should use for securing the safe that would prevent it from allowing fluid to leak in?
Answer: If this is going to be a permanent installation, I'd go about doing two things:

At every mounting bolt, put a grommet/bushing between the safe and the floor of the truck. This will provide a bit of cushioning for the safe to ride on, keeping the safe up off of the floor itself. This in turn will help prevent rattles down the road.
Once the mounting bolts are in place, coat the exposed bolt heads with some type of sealant. This will help prevent the leakage you're worried about, plus it will prevent rusting/deterioration of the bolts over the long haul. It will also prevent the water seepage into the cab. Just ensure you cover the entire area with the sealant.
Comment: Presumably you will have drill holes through the floor pan.  I'd spray the exposed bolts/nuts with a layer of primer and then undercoating.
Comment: @Blackbeagle - Good point. Could even use POR15 in such a case. One application and good protection.
Comment: Why not edit that into the answer?


After the loss of Kurama does Naruto have the Six Paths Sage Mode?

Question: We are all sad what happened in the last chapter of Boruto manga. Now I am thinking:  Does Naruto have, and can he use, the Six Paths Sage Mode without Kurama?
Answer: He still has his Six Paths chakra. He still has everything from the war, except his Truth-Seeking Ball. The TSB have been destroyed in the war, and in his battle with Sasuke, and he can't reproduce others. The yellow chakra cloak is just Kurama's cloak, and has nothing to do with Six Paths Sage Mode.
Answer: Yes he does. But some people part of the Naruto fandom tend to get Six Paths Sage Mode mixed up with a similar chakra mode that Naruto has.
According to https://narutofanon.fandom.com:

Six Paths Sage Mode (六道仙人モード, Rikudō Sennin Mōdo) is a form which empowers the user's abilities to a far greater extent by utilising the Six Paths Sage Chakra. It is a divine state gifted by Hagoromo Ōtsutsuki to those who have an iron faith and the guts to never give up.

According to https://comicvine.gamespot.com:

Truth-Seeking Orb (求道玉 Gudōdama) are black orbs made up of chakra of all natures, including the five basic elemental natures and Yin-Yang release. Although it is usually seen as hand-sized by default, it can exist in any shape or size, depending on the amount of chakra within it.

Now as to what has confused the fandom between Six Paths Sage Mode and the mode where Naruto generates Truth-Seeking Orbs.

THIS is Six Paths Sage Mode.
Now, as to the mode where Naruto generates Truth-Seeking Orbs.

THIS is when Naruto mixed Six Paths Sage Mode with his Nine-Tails cloak. Some people get it confused.
To answer your question, Naruto still has Six Paths Sage Mode after the death of Kurama, but he can no longer generate Truth-Seeking Orbs as he did in Naruto Shippuden.
Answer: As Kurama explains it, Baryon mode uses both Kurama & Naruto's chakra as raw materials collide and form brand new energy, which means raw material once used, it's gone forever. It's not just Kurama is gone, but also a portion of all Bijuu chakra and SOSP chakra and quite a large amount Naruto's chakra as well. At this point, Naruto isn't the same as he faced against fused Momoshiki.


"(the) most greatest" or "(the) greatest"

Question: I'm a beginner so soory for my English. I don't know and couldn't find which one is right on the internet. Is"(the) most greatest" used by people? Or like, is it right to use that? I saw this in a book. Although I say "(the) greatest" normally, just wanted to make sure. Thank you!
Answer: You are right that "the greatest" is correct.
This article explains about comparatives and superlatives. Some adjectives (as the article says, mainly shorter ones) form their comparative and superlative with suffixes (-er and -est), and some (longer words) use more and most.
Examples:

"The most beautiful island in the world."
"The greatest story ever told."

There are a few exceptions (e.g. good-better-best), but using both most and -est together is not correct in standard English.
If you saw "the most greatest" in a book, perhaps it was dialog spoken by a child, or some other example of purposely incorrect language. That is an expression we don't normally use in English.
Answer: There are two ways of expressing this:

the most great
the greatest

Either of the above phrases is possible. Most great is not wrong, but the more common, and shorter, is simply greatest.

Only one thing (or group of things) can be the greatest. Combining the two words to say most greatest is redundant and, while understandable, would be considered wrong.


How could sequential mandibles evolve?

Question: How could an alien creature evolve with a set of multiple mandibles attached to a single maxilla? The mandibles would have different types of teeth, and all jaws would be planar, with some teeth attaching to the middle of the jaw, rather than the edge. The maxilla and braincase (which supports the sensory organs) are jointed, but not fused
Comment: I'm having a hard time picturing this, could you attach a sketch?
Comment: Why was this closed? What details could I add that would help in answering this question?
Comment: related [multiple jaws](https://worldbuilding.stackexchange.com/questions/53971/could-a-creature-have-multiple-jaws)
Answer: Once upon a time there was a shark-like creature called Helicoprion

Helicoprion is an extinct genus of shark-like eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extinct cartilaginous fish, the skeleton is mostly unknown. Fossils of Helicoprion are known from a 20 million year timespan during the Permian period from the Artinskian stage of the Cisuralian (Early Permian) to the Roadian stage of the Guadalupian (Middle Permian). The closest living relatives of Helicoprion (and other eugeneodonts) are the chimaeras, though their relationship is very distant. The unusual tooth arrangement is thought to have been an adaption for feeding on soft bodied prey, and may have functioned as a deshelling mechanism for hard bodied cephalopods such as nautiloids and ammonoids.

They seem to be the best candidate to be the progenitor of what you are describing.

How could sequential mandibles evolve?


Question concerning the cause of the rise of water in a spinning bucket in empty space according to Mach

Question: According to Mach we can attribute the fact that in a spinning bucket with water the water rises to the edges of the bucket just as well to the whole Universe rotating around the bucket, as to the spinning of the bucket itself. But how can the whole Universe be rotating? With respect to what? And doesn't it take a lot of energy to make the Universe spinning? Or has the Universe has been spinning all the time, so that if we make a bucket spinning we create a spinning difference between the bucket and the spinning Universe?
Answer: The Universe (including the water in "Newton's bucket") is rotating only in relation to the bucket.  In this sense, the energy required to set the Universe spinning is not a lot.
The water in "Newton's bucket" is part of the Universe, and the bucket is spinning with regard to the water and the rest of the Universe.  But friction between the bucket and the Universe outside the bucket is insufficient to cause measurable effects in the rest of the Universe.  Only the water part of the Universe inside the bucket has sufficient friction with the bucket to measure the effect of the rotating Universe's contact with the bucket.
If there were significant friction between the outside of the bucket and the rest of the Universe, it would take more energy to create a measurable effect on the rest of the Universe.
Mach took the position that all motion is relative.  However, it would be counter to his argument to say that the Universe is an abstract and absolute entity that rotates.  Rather, his argument signifies that it's equally correct to say that space and all objects in the Universe rotate in relation to the bucket, as it is to say that the bucket rotates in relation to the rest of the Universe.
Answer: Well from the buckets perspective that is what's happening.  That's more or less the point as far as I can tell.
It doesn't take much energy to make the universe spin around the bucket though; the bucket has a fairly low inertia and can be given that circular motion fairly easy by a human.  That's all it takes to make the universe spin from the perspective of the bucket.
Does that answer your question?
Comment: @JMac-Mach wasn't talking indeed about the whole Universe rotating around the bucket. But suppose you could make the Universe (all the material that's in it) rotate around the bucket. You are at rest with respect to the bucket, so you feel no acceleration. Or does frame dragging (of which Mach didn't know) provide the acceleration, which would let the water level rise just the same? And in the case you spin around your axis, don't you feel yourself spinning anymore if all the stars are removed (as according to Mach the rotation can only exist relative to the stars)? GR wasn't there yet!
Comment: @descheleschilder : In an empty Universe, you must eject something from your body in order to rotate.  From Mach's viewpoint it would be correct to say that the ejected matter rotates relative to you (as you and the ejected matter would be the only objects in the empty Universe). But you would feel yourself spin only because portions of your body rotate with unequal angular velocities relative to their common axis and to each other.  Frame dragging would measurably affect empty space & your relative trajectories if you and the ejected matter were massive enough.


What are the advantages if we wake up before Sun-rise according to Vedas?

Question: what are the advantages if we wake up before sunrise according to our scriptures.
Thanks!!!
Comment: Suryavanshi means "**Descendant** of Surya" not one who gets up before sun rise.
Comment: @TheDestroyer Thanks, I fixed it.  That's one of the perks of being a moderator, I can edit a comment long after it's been posted.
Comment: There are advantages to waking up before sunrise, but as @Surya  said it has nothing to do with the word Suryavanshi.  Suryavanshi refers to the members of solar dynasty, who are descendants of Surya's son Vaivasvaya Manu.  Rama was a solar dynasty king.
Comment: So I suggest you take out the Suryavanshi part and just ask about the advantages of waking up before sunrise.
Comment: @KeshavSrinivasan It looks like you pointed me instead of Surya.
Comment: It is not so much the waking up, it has more to do with japa and meditation. There is a certain calmness to the world at the hours of sunrise and sunset and man has a predominance of sattva at those hours. It is easiest to put the mind into a meditative mood at those times. The hour before sunrise is sometimes referred to as the hour of Brahman. It is the easiest time to attain deep meditation.
Comment: One of the reasons why it is recommended to wake up around 3 or 4 A.M is because of bad dreams. After 4 A.M, people get those dreams which should be avoided.
Answer: Humanity's relationship with nature is unbreakable. We depend on her for everything -- sunshine, rain, food, air, clothing and more. Hence it is imperative that her laws
are not flouted. The one and a half hours just before sunrise is known as Brahmamuhurta. At this time the expanse of the sky will have a rosy-red hue. A few stars may
also be visible. This sacred interval is also known as the Amritavela. This is the best time to get out of bed and meet the day. All the birds and animals that Mother
Nature has assigned to awake at this time are indeed up by then. Hence they are able to enjoy the sacred bliss of those pristine moments during the Amritavela.

कुचेलीनं दान्तामलोपचरिनं । भवाशीनं निष्टुरभाशीनं च ।।
सूर्योदयेच स्थमितां शयनं ।। विममुच्चती श्री यदी चक्रपाणी ।।

Kuchelinam dantamalopacharinam ,Bahvashinam nishthurabhashinam cha
Sooryodaye chastamite shayanam , Vimunchati sreer yadi chakrapanih
On the other hand, those who arise at this time will experience increased health, strength and spiritual lustre. The following verses from the ancient Hindu text,
 Atharva Veda (9.68.22), makes it clear that "Bathing in the rays of the rising sun at this time will destroy many illnesses."

उदायांनित्य रश्मीहिभी: शिर्षणोहो: रोगाः निनाश: ॥

"Udyannaditya rashmibhih seershno rogamaneenashah."
Obviously the meaning here is that the rays of the rising sun have certain special qualities that are not found in the sunrays at other times.
"Atharva Veda" अथर्ववेद describes the curative power of the rays of the rising sun:
"The rising sun removes all the factors which cause death." (17.1.30).
"The rosy rays of the rising sun cure heart disease and paleness." (17.1.30).
These are some examples. Similarly, the Rig Veda ऋग्वेद,  text, also describes how the rising sun dispels all heart disease and jaundice (Rig Veda 1.50.11).
The scriptures exhort us to sit facing the east at sunrise, to perform worship (sandhya) and a fire sacrifice (homa). The Srimad Bhagavata, the gold mine of devotion,
Says that the main means of acquiring health through worship of the sun is the surya namaskara. ("Arogyam bhaskaradichhet.) The surya namaskara is also to be performed
facing the sun. All this can be completed only if we wake up before dawn.

ब्राह्ममुहूर्ते उत्तीहीष्टेथ । स्वस्थो रक्षःमायूषः ।।

Brahme muhurte utthishteth
Swastho raksharthamayushah
(Ashtangahridaya: Sutrasthana)
Comment: I think "उदायांनित्य रश्मीहिभी: शिर्षणोहो: रोगाः निनाश: ॥" means "the rising sun rays are capable to destroy diseases...."
Comment: Looks like this answer is taken from http://archives.amritapuri.org/matruvani/vol-01/jul01/01mv07dawn.php but I see no citation. Plagiarism is against SE rules. See [here](http://hinduism.stackexchange.com/help/referencing).
Comment: @ sv , Yes you are quite correct , thanks for letting me know that " "Plagiarism is against SE rules." I am well aware of this , and also with disadvantages of  copy-paste rules. I fully appreciate your concern. Well for starters and novice person like me , at least for some time their is a need for take readymade ref. from outside source. As I will get more familiar with BASICS in some future , my ability  to give answers without some support will get improved .So this copy paste method is for short time only . Well anyway Thanks again .
Comment: Refer this post [The copy-paste issue, Hinduism version](http://meta.hinduism.stackexchange.com/questions/48/the-copy-paste-issue-hinduism-version) and also don't place space between "@" and username. And also edit and mention the source of information else we have to take it down.


command line tool to remove selected tags from mp3 files

Question: Using MP3 Diags to clean up my mp3 collection, I've discovered that in addition to the ID3v2 tag, some files also have a Lyrics3, ID3v1, and some an APE tag. Are there command line tools out there to remove all but the ID3v2 tag?
Comment: Update: to remove the ID3v1 tags I used eyeD3, for the other two tags I read the mp3 files into python and deleted everything between the tag delimiters. For [Lyrics3](http://www.id3.org/Lyrics3v2) tags, they are: "LYRICSBEGIN" and "LYRICS200", for [APE](http://wiki.hydrogenaudio.org/index.php?title=APE_Tags_Header) tags, "APETAGEX" and again "APETAGEX".
Answer: I've used id3v2 before and found it to be quite good.
There are some others according to aptitude: id3 and id3tool. Assuming you have a Debian-based system:
aptitude search id3. I'm sure other package managers should have a search facility.
I'm not sure these will be able to do everything you want (by which I mean I don't know anything about Lyrics3 and APE), but you can take a look. Certainly id3v2 has -s, -d and -D flags to remove id3v1 tags, id3v2 tags, and both, respectively (according to its man page).
Comment: `id3v2` worked perfectly, and it's in the Fedora repos so may be for your distro as well.  `dnf install id3v2`
Answer: Have a look at eyeD3 a command line utility and python library for manipulating id3 tags. To emove lyrics and ID3v1 tag from all mp3 files in the current directory just run
eyeD3 --remove-lyrics --remove-v1 *.mp3

If eyeD3 reports a problem while writing the tags try to rerun the command again as it seems to fix the problem.
I am not totally sure what an APE tag is but you can also remove arbitrary user tags from an mp3 file with eyeD3.
Comment: I've tried to use eyeD3, however these lyrics tags are outside of the ID3 tag, so eyeD3 can't read or remove them. The --remove-v1 solves at least one of the problems.
Comment: Can eyeD3 show the lyrics? Maybe you have to use either `-1` or `-v` to show the tag. According to the documentation it should be able to handle lyrics. Maybe `--remove-comments` helps
Comment: No, the problem is exactly that, none of the tools I've found so far (eyeD3, id3tool, id3v2) are able to show these lyrics as they are independent of the ID3 tag. In MP3 Diags, it shows the ID3v2 tag (which of course has the ability to store lyrics), but also additional tags, ID3v1, and these APE and Lyrics3 tags. I'm looking for a way to strip away all these extra tags and just leave the ID3v2.
Answer: To remove the APE tag, use versions of the apetag tool that support the erase mode:
apetag -m erase -i file.mp3

Beware the old apetag (1.12) seems unable to parse an MP3 file with an ID3 v1 tag.
Answer: I've successfully used rmlyrics3 to remove lyrics3 tags.


Core in libc.so.1

Question: I am using Solaris 10 and my C program is getting crashed and creates a core file. On debugging, it seems like the core is created in libc.so.1. Please let me know if anyone have any clue.
Below is the dbx report.
dbx prock.new core
For information about new features see `help changes'
To remove this message, put `dbxenv suppress_startup_message 7.6' in your .dbxrc
Reading prock.new
core file header read successfully
Reading ld.so.1
Reading libsocket.so.1
Reading libnsl.so.1
Reading libl.so.1
Reading libpthread.so.1
Reading librt.so.1
Reading libthread.so.1
Reading libc.so.1
Reading libaio.so.1
Reading libmd.so.1
Reading libc_psr.so.1
WARNING!!
A loadobject was found with an unexpected checksum value.
See `help core mismatch' for details, and run `proc -map'
to see what checksum values were expected and found.
dbx: warning: Some symbolic information might be incorrect.
t@null (l@1) terminated by signal SEGV (no mapping at the fault address)
0xffffffff7ea3bc14: strcasecmp+0x0134:  orn      %i0, %i3, %i0
(dbx) where
=>[1] strcasecmp(0x10014b68e, 0x57, 0x7ffffc00, 0x1001332d7, 0x27, 0x24), at 0xffffffff7ea3bc14
  [2] 0x10000af48(0x27, 0x10014b68e, 0x57, 0x10014b68e, 0x57, 0x0), at 0x10000af48
  [3] 0x100009c08(0x27, 0x5e, 0x0, 0x9, 0x1001332c3, 0x2b), at 0x100009c08

(dbx) whereis strcasecmp
function:       `libc.so.1`strcasecmp
(dbx)

My solaris version is
               Solaris 10 8/07 s10s_u4wos_12b SPARC
   Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.
                Use is subject to license terms.
                    Assembled 16 August 2007

Comment: Looks like the arguments being passed by you to strcasecmp are improper (either corrupted or strings are not NULL terminated etc)
Answer: No, the problem is not with the C standard library. You're passing an invalid parameter (NULL string pointer, etc.) to strcasecmp(). Without actual code (which you haven't posted), it's not possible to deduce what exactly the error is.
(Also, you better compile your program with debug symbols - with optimization turned off! If you're on Solaris, you most probably use GCC:
gcc -O0 -g etc...

)
Comment: Yes, this is my viewpoint too. There should not be a problem with C library.
Answer: 1) Compile your program to include debug information (add "-g" to the list of options to your compiler), so that you actually get information instead of this:
 [2] 0x10000af48(0x27, 0x10014b68e, 0x57, 0x10014b68e, 0x57, 0x0), at 0x10000af48
 [3] 0x100009c08(0x27, 0x5e, 0x0, 0x9, 0x1001332c3, 0x2b), at 0x100009c08

2) DBX will now tell you which of your functions has been calling strcasecmp. Step through the source (or have it generate log output), check the parameters of the fatal function call for anything out of the ordinary (like invalid pointers).
The chances of you discovering a bug in a libc function are infinitesimal compared to the chances that your call to that function was in error.
Comment: Thanks DevSolar, I will add some more debugging options and will be back.
Answer: 1) Run bt (backtrace) to see who is calling strcasecmp [ this will list frames like #0, #1 ]
2) Now jump in to the specific frame to get the values [ frame 0 ]
3) Then display / print the value of the argument passed to strcasecmp ( using print or display)
I feel the argument is NULL on calling strcasecmp and that's why you are getting segfault.

Core in libc.so.1


How many coils does an NFC tag contain?

Question: I'm trying to wrap my head around NFC tag inner workings. In particular I'm curious whether different coils are used for harvesting energy and to transmit data. This random NFC tag IC datasheet I found has separate pins for power and antenna, which makes me think that there are at least two coils involved. However, wont the two coils interfere with each other given their proximity? Does this imply that NFC tags have different stages of accumulating energy and sending data, or is it happening simultaneously?
Comment: That chip only has one antenna connection (AC0/AC1 being both ends). The `V_EH` I think you are referring to is an output to provide energy harvested from the antenna to external regulators which can then be used to power the VCC/user interface if not self-powered.
Comment: No, i understand that much. But the VCC implies there is another coil since it's a tag and is meant to use induced current? Or does it have just a single coil both used for power and as an antenna?
Answer: NFC tags have exactly one antenna and your IC also has only one set of pins for an antenna. To my understanding the different standards on which NFC tags are based on do not allow the use of more than one antenna. In ISO/IEC 14443 and 15693, for example, there are clearly defined antenna classes which "only" contain one antenna. Both data transfer and power transfer must occur over the same antenna.
Regardless of this, there is always an influence on energy harvesting during data transmission. The energy harvesting (rectification) happens permanently, but the amount depends on the ongoing communication state. For example: When the tag transmits, it shorts the antenna (depending on the standard), which means that no energy can be received. This means there must always be enough energy stored to ensure that the communication is not interrupted.
Now two edge cases can occur. There may not be enough energy for communication (e.g. due to a too long distance). Therefore, many tag ICs have the possibility to be powered externally (the VCC pin on your IC). Quite often, however, the other case occurs, meaning there is more than enough energy available. Your tag IC allows the excess energy to be used by providing an unregulated DC output voltage at pin VEH (which is a special feature).
Answer: NFC tags usually have one coil for harvesting energy and transmitting data (simultaneously). The tag ICs may have seperate power pins for applications where e.g. the tag needs to be powered even when there is no reader present.

How many coils does an NFC tag contain?


How to exit login screen and start commandline while at login screen

Question: I am at the gnome 2 login screen but I want to exit and re-enter command-line environment.  I remember there was a combination hot key one has to invoke.
Comment: On which operative system are you?
Answer: Are you looking for Ctrl-Alt-F1 ?
This will switch to the first virtual console. Usually several virtual consoles are available from F1 up to F6. The 7th is usually the one used by the login screen, so you can switch back using Ctrl-Alt-F7 (or whatever is the relevant one).
Comment: on my ubuntu 20, f1 seems to belong to the login screen, so nothing happened when i pressed ctrl+alt+f1, ctrl+alt+f2 worked in my case
Answer: Ctrl + Alt + F1 (there are also terminals on the following F-keys, for me up to F6).
To get back to the GUI, use F7 instead.
Comment: I actually tried that - I know what the problem is now.  For some reason my keyboard is not active at the login screen...
Comment: **"there are also terminals on the following F-keys"** thank you, my fedora 28 is F3


Why do we still have accents?

Question: I have read a few questions regarding pronunciation which is complicated by accents across the US.  I assume this is also true for other languages.  In most dictionary references, a pronunciation key is provided.  If the words are taught with this information included, wouldn't we all sound the same?  For example, http://www.merriam-webster.com/dictionary/cars
Comment: To answer the question, we all still have accents because we all learn to talk before we go to school. School can't change the way we talk and doesn't really try to; it just makes people think whatever they do is wrong. This is hardly ever helpful information. The fact is that English speakers are not taught about their language and usually end up thinking that pronunciation is determined by spelling, which is a really silly notion.
Comment: We have accents  and dialects because some people speak differently, groups become splintered, and these splinter use their different speech to separate themselves (over longer periods of time, this is how language evolves too).
Comment: I don't have an accent -- it's all those other idiots out there that do.  (Actually, Webster's in particular made great inroads in minimizing regional accents, but it's an uphill battle.)
Comment: @John: My father hasn't lived in Lancashire or interacted much with Lancastrian speakers for well over 80 years, but he still has a very strong accent. I on the other hand have a reputation for reflecting the accent of the people around me if I stay anywhere for more than a few days, even though I make no conscious effort in this respect. Is there any research into why there can be such huge differences between people in terms of "dialectal retention"?
Comment: @FumbleFingers I'm similar, though my folks' Oldham accents are a little tempered by their 54 years in Scotland. I started school in Cumbernauld with a broad Lancs accent and had to work really hard to shed most of it (teachers really hated 'lurry' for 'lorry' and 'butt-cher' for 'butcher' (local pron 'bootchur'). As a result my accent is part Oldham, part everywhere I've lived and part whoever-I-last-spoke-to.
Comment: Thank you for the comments.  I am unclear why this question is voted down.  It is a valid question, is not a duplicate, or opinion based.  It is not a troll soliciting the banishment of cultures or punishment of teachers.
Answer: I think you're minimizing how complicated this would be.
First of all, you're confusing pronunciation and accent. It's an oversimplification to say that people with different accents pronounce things differently. That's partially true, but it would be more accurate to say that people with different accents say the same pronunciation differently!
A pronunciation key tells you which individual sounds make up a word. Different people say those sounds differently. Here is a reasonable description of what I'm talking about.
In other words, two different people can read the same pronunciation key and say different things, and both would be correct. So a pronunciation key doesn't really do much if your goal is to get rid of accents.
So sure, we can see that the pronunciation of "car" is /kär/. Now, what does that sound like? Somebody from Boston has a different answer from somebody from California. Both are correct.
I suppose you could force everybody to learn one phonetic alphabet (whose?) and force them to only use that, but how would you go about it? How are you paying for the massive amounts of training required? How are you going to handle the backlash from people who don't want to change the way they speak? How are you going to enforce this over time so the accents of different areas don't drift away from each other again?
Comment: I didn't realize that the sound of a pronunciation was different per accent.  I always thought that the phonetics would sound the same and were not influenced by accent.  Thank you for the clarification.
Comment: @Jammin4CO No problem. This stuff is interesting, but it's very complicated. Look into linguistics and how they codify the details of exactly what you're doing with your mouth, teeth, tongue, breath, and even nose when you're saying a single sound. That's the alphabet that can tell you exactly how something "should" sound, and that's what you'd have to get people to learn. Then you'd have to enforce its use, and then round up anybody who refuses to cooperate into "language reeducation centers" for their daily beatings until they obey your new One  True Accent laws. :p
Comment: @Jammin4CO [Here](https://en.wikipedia.org/wiki/Manner_of_articulation) is a good starting point. Have fun going down the Wikipedia rabbit hole!

Why do we still have accents?


Company of Heroes balance

Question: I recently got Company of Heroes and the two expansion packs. I have heard that CoH: Opposing Fronts pretty much broke the balance that existed in the original. Does anyone know if the gameplay has been rebalanced with the release of CoH: Tales of Valor?
Comment: Questions about balance are usually questions that are [not based on an actual problem](http://gaming.stackexchange.com/faq). See ["Why did They design it that way, anyway?", and why do we allow or disallow these?](http://meta.gaming.stackexchange.com/questions/2429/why-did-they-design-it-that-way-anyway-and-why-do-we-allow-or-disallow-these) for more information...
Answer: It broke the balance when it initially came out but that has long since been fixed in patches. All of the races have advantages and disadvantages as well as different ways of playing them. The tales of valor units give options rather than any particular advantage, and people choose not to use them even when they are available.
Answer: Since this question is not closed by this date I will add that the patching has not ceased.  Further unbalanced remainded specially in matches between:
<code>German vs British [halftrack + pioneer rush ; now British infantry does much more damage to the halftrack]
Americans vs Panzer elite [Infantry command and heavy rangers vs anythin that PE would throw; now the Americans cannot have a blob that can match PE without using weapon support or vehicles]
</code>
You should note however that the game is now scarcely played, meaning that the more balanced stats that the game sees are not as significant as before. There is however, a very effective response to any rush strategy
Answer: I think that CoH: Tales of Valor mostly added more game modes.  The main changes it makes to the game balance is to add additional optional units that can only be used by Tales of Valor players, and are not available to 'mere' CoH: Opposing Fronts players.  Since I don't think that letting some people use some units and not others adds much balance, I'm gonna vote no.

Company of Heroes balance


What is the Intended Usage of the ASP.NET Session?

Question: In an ASP.NET application you can store pretty much anything in the Session as long as you can handle the cost. What is the intended usage and what is most frowned upon when using the Session to store data?
Answer: Any user specific data that has to be persistent across various pages of an application to the logged in user can stored in a session. The objects to be stored in Session need to be serializable.
Usually, it is recommended that the session should be used a little sparingly, because with an increase in number of concurrent users,the load on server memory increases and at one point, it recycles the memory causing all session data to be dumped. This causes a premature timeout of the session.
Answer: I like to use the session to hold keys, or indices into server-side data that doesn't need to be persisted between pages.  That is lighter weight than persisting the whole object(s)
Answer: As of ASP.NET MVC2 TempData is stored in the session.
Some uses of it are described here: ASP.NET MVC - TempData - Good or bad practice and here Tempdata Improvements.
Answer:
Session are used to persist information for each client.

Everytime a new client establishes a connection asp.net starts a new session for the newly connected client. You might want to keep some information persistent to current session of the client and display information on perform some operation based on his/her session information.


What does the wheat symbol above a follower mean?

Question: I've just put in two farms but there are no fields, it just consolidated the adobes. And now when I click on a dwelling to get my followers to build they have a wheat symbol over their heads and just sit down and won't build. How do I fix this?
Answer: I have never seen this symbol in game, but usually symbols above follower's heads indicate they are unable to perform the task because something is preventing them from doing so. In this case, it is likely wheat, and here is why: Once you have built a farming settlement in Godus, wheat becomes a requirement for building Adobes. Do you have wheat in reserve? If not, you might need to use some of your gems to buy some.
It is strange that the fields did not build, as that is probably the source of your problem and could be a bug.
Answer: Once you have farming settlements, it costs a certain amount of wheat (depending on the plot size) to build a new building. Wheat is also used to give followers a burst of stamina, and for some upgrades, and the number of wheat fields you have is counted to unlock certain cards. If you don't have enough wheat to start building, the builders will wait at the plot with a wheat symbol.
Farming settlements don't automatically start building wheat fields, but they do generate farmers. Rather than the blue builder symbol, the settlement should have some green farmer symbols. As with building new buildings, you can click the settlement to send farmers out to build nearby empty plots into fields. Building a new wheat field does not cost wheat.
If there are no empty plots close enough to the farming settlement, you won't be able to send farmers out by clicking the settlement. You can, however, still leash farmers from the settlement to send them to plots further away, which they will farm.
Each plot only needs one farmer regardless of the size, but larger farms give you more wheat every time you harvest it.


Maintain version history across different root extensions (.doc vs. docx)

Question: I am looking for an Out of the Box/ Easy configuaration change within SharePoint 2010 to maintain version history across different root extensions (.doc vs. docx)
Comment: Maintain version history in what way?
Answer: As far as i understand there is no easy configuration to enable versioning across farm or web application. There are other ways to do this.
You can enable versioning at document library level. You can follow the steps from here:
Enable and configure versioning for a library
Other is you can write a feature to enable versioning in your specific document Library.
Programmatically Enable Versioning to a Sharepoint List
Answer: We have the same issue. Versioning is turned on, we have documents in the library with previous versions, and now we want to convert the .doc to .docx without losing version history.      SharePoint only recognizes docs as new versions if filename is exact match, including file extension, so we can't add a .docx and have it added to the .doc version history.
  It seems our best option so far is to create a separate library for the .docx documents and add a lookup column pointing back to the previous doc.


How to remove the glue stain on shoe sole?

Question: I was applying some super glue to stick back my glue sole. However, some of the glue stained the shoe sole, as shown in the picture below. I have tried using turpentine, but to no avail. Is there any other ways to remove the glue stain?
Comment: Superglue dissolves in acetone.  I assume you tried that.
Answer: Chemicals might do more damage than help. I would try some fine sandpaper and a good amount of careful and patient elbow grease.
Recommendation: next time please be A LOT more careful. Or take the shoes to a specialist for repair. Some spill might be expected when the job is done by a non-specialist, but here we are looking at some "horror movie".
Answer: Superglue softens with heat, you could try blowing a hairdryer at your shoe.  The problem is that you may loosen the manufacturer's glue that's holding your shoe together.
Answer: The glue can be softened with acetone (nail polish remover), but be aware that it might have a similar effect on the shoe itself, depending upon what it's made of.
Answer: When I have to clean off glue, sometimes the only way is to lift up a corner of one part with a knife, and very slowly and gently peel the glue away. Then the next scrap, etc.
The reason it needs to be peeled slowly, is so that the glue can stretch into strands, which become thin enough to break away. If you peel too fast, the bit you are holding will tear off, and you won't be able to remove much at a time, leaving ever smaller fragments behind.


Good at Backend, but bad at front end

Question: I want to start web development, I have been learning php.
I have experience in Java, Python, and C++
This experience has made me good at the back end side of web development.
But I am terrible at design and graphics.
I want to start website.
What do you guys suggest I do?
If your suggestion is to get better at graphics, what would be a good way?
I also want to know what you guys use for design and graphics, and what would be a good learning spot for it?
Comment: I'm in this boat as well, mainly I focus on back-end stuff and just stray away from doing front-end things.
Answer: The quick and dirty approach is to just do it. Make a website. You see websites everyday. What elements do you like from the sites you visit? What element's don't you like? You will get better the more sites you do.
Now, if you want to put some real effort into it, there are a few books you can pick up that will help you with UI design and layout:

Don't Make Me Think (as has been mentioned by other people)
Letting Go of Words
Forms that Work

All three are very good and will give you the tools you need to start designing functional websites that your users will be able to easily use.
Graphics aren't as important as you think for a website. They give it that 'wow' factor for sure, but if the layout and functionality is broken, it won't save your site. It's more like the icing on the cake.
For graphics, get a graphics program that isn't Paint, and Google tutorials on it. Find one that looks interesting and do it. Try doing 3 to 5 tutorials a week. You'll find they get easier and easier. This is how I taught myself how to use Photoshop. I'm by no means a graphic artist, but I can make icons and do decent graphics.
Comment: I agree, take note of sites that you like, and start trying to combine them. You can look at sites that sell website templates (I've used TemplateMonster.com before) as inspiration--I'm obviously not recommending stealing graphics, but you can try to re-create layouts you like to get a feel for what works well.
Answer:
read Don't Make Me Think, by Steve Krug - this will provide functional help so your user-interfaces work well, and teach you about usability testing so you can design for the users and not just for yourself (a common developer problem)
hire a pro to make stuff pretty - for when it matters, a good graphic artist can make the difference between "It's okay" and "WOW I GOTTA GET ME SOME OF THAT"

good luck!
Answer: The book Web Design for Developers: A Programmer's Guide to Design Tools and Techniques by Brian P. Hogan is a great starting point to learn how to do web design coming from your background.
Answer: I always thought of myself as pretty creative, but realized quickly, when I made a go at some web projects that design really is an entire field that can take just as much time to learn and keep up with as programming. I learned to expect my graphic designs be on par with a graphic designers code.
You could definitely go for it, but recognize that it is a serious time committment.
Answer: Probably the biggest thing you can do for yourself if you plan to use any of the popular blogging platforms (e.g. blogger.com) or software (e.g. Wordpress, Drupal) is to use a pre-made theme. You can learn from each of these, and in the end, the only thing you may need to do is tweak an existing theme. I soon recognized that doing anything with graphics or design is pretty specialized, so the advice to hire this skill out is good advice.
The book recommendations on this thread have been great!

Good at Backend, but bad at front end


Method of Variation of Parameters Problem

Question: I'm trying to solve this second order DE by method of variation of parameters, $y''+3y'+2y=e^{-t}$.  I got $y_p = (t-1)e^{-t}$, however the solution says it's just $te^{-t}$, and I don't understand how they factored out the $-1$ term.  I would appreciate some clarification. Thanks!
Comment: How did you get your solution and what are the initial conditions?
Comment: Found yh and yp, then calculated W, W1 and W2.  From that I found V1', V2' and then subsequently V1 and V2.  Then I subbed back into yp and found y(t) by y(t)=yh+yp. There weren't any IC.
Answer: Both your answer and the book's answer are correct.  This is because the "particular solution" $y_p(t)$ of a non-homogeneous linear ODE is not uniquely defined.  To see this, suppose that we have two different solutions to your equation:  $y_{p1}(t)$ and $y_{p2}(t)$.  These functions satisfy the ODEs
\begin{align}
y''_{p1} + 3 y'_{p1} + 2 y_{p1} &= e^{-t}, \text{ and} \\y''_{p2} + 3 y'_{p2} + 2 y_{p2} &= e^{-t}. \\
\end{align}
If we subtract the second equation from the first, and define $z(t) = y_{p1}(t) - y_{p2}(t)$, we obtain
$$
z'' + 3 z' + 2 z = 0.
$$
Thus, any two solutions to the non-homogeneous ODE will differ by a solution to the homogeneous ODE.
In your case, the "book solution" is $y_{p1} = t e^{-t}$, while your solution is $y_{p2}(t) = (t - 1) e^{-t}$.  The difference between these two solutions is therefore $z(t) = e^{-t}$.  But the general solution to the corresponding homogeneous ODE is
$$
z(t) = c_1 e^{-t} + c_2 e^{-2t},
$$
which is exactly what you found in the case $c_1 = 1, c_2 = 0$.
Comment: This is a common student confusion, BTW, which I commented on in my [recent answer to another question.](https://math.stackexchange.com/a/2488045/248639)
Answer: you have non-homogeneous differential equation.
let's set $y(t)=y_h+y_p$
for solving $y_h: 0=y''+3y'+2y$ you guess $y=e^{\gamma t}$. i'll spoiler you and say that $\gamma=\begin{cases}-1\\-2\end{cases}$ so $$y_h=c_1e^{-t}+c_2e^{-2t}$$
now when you solve $y_p$: for $e^{-t}$ you guess $y=ae^{-t}$ but because when you try $y=ae^{-t}$ you get homogeneous ODE you multiply the guess by $x$ and then you guess again using $y=ae^{-x}x$. i'll spoiler again and say that for the function $$\frac{d^2}{dx^2}\left[ae^{-x}x\right]+3\frac{d}{dx}\left[ae^{-x}x\right]+2ae^{-x}x=e^{-x}$$ you get $a=1$ so $y_p=e^{-x}x$
thus $y=y_h+y_p=c_1e^{-x}+c_2e^{-2x}+e^{-x}x$
from initial conditions you can find $c_{1,2}$.
I don't know how you did it but this is the easiest way to calculate this kind of function i know, and it is easy to found mistakes.


Mass production rate vs mass consumption rate in solid rockets

Question: Do the two terms mean the same? mass production rate, mass flow rate and mass consumption rate in a solid propellant rockets.
Comment: It would be better if you could **quote or link to the places were these are used**, i.e. where you found them. The answer might be "yes, in general, unless specified otherwise" but where you are seeing them there might be something else going on.
Comment: @uhoh Thank you. I will keep your suggestion in mind.
Answer: Agreed that it's hard to give a definitive answer without the context in which they are used. But taking their definitions literally based on the terminology:

mass production rate = rate at which product gas mass is generated by burning propellant (no mass can actually be "produced" here, but if we are looking at a nozzle, the mass of interest is product gases, which are being "produced" by burning propellant

mass consumption rate = rate at which propellant mass is converted to product gases (aka the rate at which propellant is combusted)

mass flow rate = the rate at which mass is flowing through the nozzle

Based on these definitions, the first two are equal if the only mass being ejected from the rocket comes from propellants. (I am intentionally neglecting mass changes due to staging, since this question is likely in the context of engines/nozzles). This is a reasonable assumption, since if you are changing the mass of a rocket from anywhere besides the propellant/fuel/oxidizer, that means something is very wrong (melting engine, breaking hardware, etc.)
These two terms should be equal to the mass flow rate when the motor is in steady state operation. If we consider the control volume to be the entire rocket nozzle/combustion chamber at the surface of the solid propellant (so that unburned propellant is not in the control volume), then based on conservation of mass, any "produced" or "consumed" mass is the mass entering our control volume. This mass can do two things: exit the nozzle by flowing through it (mass flow rate) or stay inside some portion of the nozzle.
The term steady-state indicates that the flow at any point in the nozzle is not time-varying, which means that a unit of mass that enters our control volume must exit it (mass in = mass out). Otherwise you would have a changing amount of mass at some point in the control volume, which would show up as the density at some point changing as a function of time (not steady state). So in steady state operation, all three terms would be equal.
The non steady-state case is generally during startup or shutdown (also during any times when mass flow in changes and the system is still responding). The mass flow through the nozzle is driven by the chamber pressure of the motor. When the mass flow in (controlled by the rate of propellant combustion) changes, the system must reach a new equilibrium chamber pressure that leads to the mass flow rate through the nozzle equaling the mass flow rate in. This is not an instantaneous event, since a sudden increase in mass flow in would cause the current chamber pressure to be too low to push all the mass out, which would lead to a buildup of mass and an increase in chamber pressure until the in and out flow rates are equal.


Functions with the domain having greater cardinality than $\aleph_1$

Question: Are there any examples of an algebra on elements belonging to a set of greater cardinality than that of real numbers. Can a reference to their use be given?
Comment: continuous functions on stone-cech compactification of $\mathbb{N}$.
Comment: @Norbert Thanks. This would be an example of domain having the cardinality $\aleph_2 / 2^\mathfrak c$ are their examples of even greater cardinalities.
Answer: It is consistent that the real numbers have cardinality $\aleph_2$, in which case a function $f\colon\Bbb{R\to R}$ satisfies your requirements.
If you want a set whose cardinality is explicitly $\aleph_2$ then you will have to resort, in one way or another, to $\omega_2$ which is the second uncountable ordinal (i.e. the cardinal $\aleph_2$). The function can be anything, from the successor ordinal, to anything crazy.
However, I feel that you're not talking about $\aleph_2$, but rather $\beth_2$ i.e. $|\mathcal{P(P(}\Bbb R))|$. In that case you can consider the Lebesgue measure as a function whose domain has cardinality $\beth_2$, and its range is $\Bbb R$.
(Also related: Functions on P(R) - are there examples?)
Comment: "It is consistent that the real numbers have cardinality $\aleph_2$...isnt $\aleph_1$ the cardinality of the set of real numbers?
Comment: http://math.stackexchange.com/a/490420/622 There are probably many other questions and answers about this question. But no. The cardinality of the real numbers is *not necessarily* $\aleph_1$.


Can I play chess on my Mac from the command line?

Question: If I were feeling insufficiently geekish on any particular day, and thus found the GUI Chess App to lack an appropriate amount of tech credibility, is there a way to play chess on my Mac from the command line?
Answer: Yes! The OS X Chess app relies on the sjeng engine, which has a command line version. Type /Applications/Chess.app/Contents/Resources/sjeng.ChessEngine and press enter to play:

Make moves with the coordinates of the origin and destination you want: e1e4 moves the piece at e1 to e4.
Sjeng doesn't take any command line arguments, but you can edit the config file (stored in /Applications/Chess.app/Contents/Resources/sjeng.rc). This will probably mess with your settings in the GUI Chess app; make a backup before editing.
Comment: It's worth noting that running this app may create files such as "bug_LE.lrn", "losers_LE.lrn", "standard_LE.lrn", and "suicide_LE.lrn" on your system. These files are safe to delete.


I can't use vmware on rdp win server error hyper-v

Question: I've rdp win 12 azure install Vmware 16 pro on it
and setup the app to when try run virtual machine get error that hyper-v turn off
when check it it's already off
and use all commands like hyper-v and use command bcdedit /set hypervisorlaunchtype off  and core isolation integry off
this is my rdp info
OS Name Microsoft Windows Server 2019 Datacenter
Version 10.0.17763 Build 17763
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name python
System Manufacturer Microsoft Corporation
System Model Virtual Machine
System Type x64-based PC
System SKU Unsupported
Processor Intel(R) Xeon(R) Platinum 8171M CPU @ 2.60GHz, 2095 Mhz, 2 Core(s), 4 Logical Processor(s)
BIOS Version/Date American Megatrends Inc. 090008, 12/7/2018
SMBIOS Version 2.3
BIOS Mode Legacy
BaseBoard Manufacturer Microsoft Corporation
BaseBoard Product Virtual Machine
BaseBoard Version 7.0
Platform Role Desktop
Secure Boot State Unsupported
PCR7 Configuration Binding Not Possible
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "10.0.17763.2061"
User Name Not Available
Time Zone Coordinated Universal Time
Installed Physical Memory (RAM) 16.0 GB
Total Physical Memory 16.0 GB
Available Physical Memory 13.4 GB
Total Virtual Memory 18.9 GB
Available Virtual Memory 16.4 GB
Page File Space 2.88 GB
Page File D:\pagefile.sys
Kernel DMA Protection Off
Virtualization-based security Not enabled
Device Encryption Support Reasons for failed automatic device encryption: Feature is not available, TPM is not usable, PCR7 binding is not supported, Hardware Security Test Interface failed and device is not InstantGo, Un-allowed DMA capable bus/device(s) detected, WinRE is not configured, TPM is not usable
A hypervisor has been detected. Features required for Hyper-V will not be displayed.
please help
Answer: Nested virtualization is not supported for VMware in Azure virtual machines.

Virtualization applications other than Hyper-V are not supported in Hyper-V virtual machines, and are likely to fail. This includes any software that requires hardware virtualization extensions.


Confused about 生气/着急/担心

Question: This is from a random hsk 5 practice exam I found online. Confused about the answer to 51 being 生气 here. I chose 着急. My thinking is that 着急 is most similar to anxious in English, which is why the wife was crying. The answer is 生气 though, which I didn't think would be right because of the whole crying thing. So why can you not use 着急/担心 in this context?
Answer: My opinion on this is that 着急/担心 would more or less imply that she is anxious/worried about/of something else that could happen, after that scene. 着急/担心 are for things you are uncertain about, that could turn out bad. Here she is not afraid or uncertain, she's just angry about what has already happened, so 生气 is the right answer. It's not entirely unusual to cry when you're angry.
Answer: 着急/担心 - worry, feel anxious about something/someone's action that we need to find an answer to it. (Why he is not responsive? I am so worried.)
生气 - anger, a strong emotion that is reacted toward some grievance or rejection. (How could he choose to continue watching the game but talk to me? I am furious.)
Answer: It's a joke!
I knew a woman, she told me, women often marry someone who is like their father!
This young woman goes to her parents home, because her husband is sitting unresponsive in front of the telly. At home, her dad is doing the same, and her mother has, oddly, gone to her mother's house!
生气!
Maybe a Chinese thing, cry when you are angry:
这个女孩哭着跑回家,因为班上的一些男孩子故意惹她生气。
Answer: "着急" refers to feeling anxious or restless due to urgency.
"生气" refers to being angry or upset because of someone's words or actions, "担心" expresses worry or concern about someone or something's well-being or negative outcomes.
In the context you mentioned, his husband was watching tv and did not answer his wife, this is not an emergency or dangerous situation. So 生气 is the best choice.

Confused about 生气/着急/担心


What is raw file folder obtained after using data recovery software?

Question: I recently used a data recovery software, Minitool Power Data Recovery, to recover my data from a raw partition drive, drive E. Along with my original files, an additional folder is obtained called "Raw Files" which has in itself sub folders named Adobe PDF file, MKV Video, PNG image, etc. I cannot access any PDF or image files in these folders. Some images which are accessible does not seem to belong to my original data and are repeated. Are there things part of my original data which has corrupted?
Answer: They are the results of carving. The tool you used most likely performs both directory tree reconstruction and carving as an additional attempt to recover most data. Quoting from this answer of mine:

File carvers → They scan any kind of disk and try to recover known file types by checking for specific signatures. For instance,
  JPEG files always start with bytes FF D8. This method only works for
  non-fragmented files and you don't get any clue about a file's name or
  location.
Tools that work at the file system level → They read (possibly damaged) partitions by looking at the directory tree and then use the
  information specified there to access files. For this reason they can
  access any file as long as it is listed in the file system.

Files that cannot be recovered by the second approach might be recovered by carving, thus the tool performs an additional carving step. Of course the signature matching might (and usually will) fail if the files are fragmented, so you cannot access them because their contents are not retrieved correctly.
Comment: I may conclude this raw files folder may/ may not contain my data which was corrupted?
Comment: @AnubhavSingh only you know what data was originally there and what belongs to files deleted in the past.
Answer: Data recovery software rarely discriminates between cached images from your browser and stuff you intended to keep.  It can also dredge up old data that has only been deleted, such as when someone sells a computer used and only reformats the drive instead of doing something like running Derek's Boot and Nuke (DBAN) on it.  This can be especially disturbing if it's a company which uses refurbished components to build new computers (Compaq right before HP bought them, late model Gateway, eMachine, 90s model Packard-Bell, and a few other no-names), as you can dredge up someone else's data if they got sloppy on the refurb.
When the image files are repeated, these are usually images which have come down from a website, such as an icon, and been left in cache.
In the end, it doesn't matter; if you can't load them on a working computer and open them, they're just useless bits.
Comment: It may or may not (as DR software just sees files and is unaware of your intent), but if it's corrupted to the point it can't be read or restored and read, it's lost anyway.
Comment: What you wrote is technically correct, but it doesn't answer the question.
Comment: So you mean to say that Raw files folder does not contain my original data which is corrupted?
Comment: @AndreaLazzarotto The same can be said of yours. The OP just wants to know, "are these their files?". In the end, the answer is really that you can't know if they are your own corrupted files unless you can read them.  I just hope for the OP's sake they were unimportant or backed-up ones.
Comment: @CDove fair enough. The problem I see here is that OP is asking two different and unrelated questions. The first one (the title, i.e. the actual question I assume) is "what is this folder?" while the second one, added as a small line at the bottom is "is this my data?" to which we might only answer "we do not know what your data is, we can't even look at the recovery result and we are not magicians".


USB connection broken, tried debugging

Question: I have a Galaxy S2 that refuses to be picked up by any computer. I tried different operating systems, I tried a different USB cable, I tried debugging mode. The phone still charges fine through the port but maybe the data section of it is broken. Before I take it in for repair I just want to hear if there's anything else that can be tried? I'm thinking of doing a hard reset but don't want to lose any data. Any advice would be appreciated.
Comment: I guess your phone's not rooted/modded (if so, just use TitaniumBackup). Without, you can still copy over data from the internal memory (mp3, video files and taken camera images on the 16 or 32 GB) to an external micro SD card using any [file explorer](https://play.google.com/store/search?q=file+manager&c=apps). Application data is not stored on the accessible part, so you have to iterate through each app and use the app's internal export data (like e.g. that of "MyTracks"), which is up to each app and sadly won't work with system settings like stored wifi credentials and such.
Comment: What Android version you are running? If it is 4.x, you can do a full backup via the Android SDK, using `adb backup` -- and lateron a restore via `adb restore`. This would include your apps and their data, so nothing is lost.
Comment: @BBking Yes and no. While it's mostly done via USB, it can also be done via WiFi -- see [How can I connect to Android with ADB over TCP?](http://stackoverflow.com/questions/2604727/) plus the [WiFi ADB](https://play.google.com/store/apps/details?id=com.ttxapps.wifiadb) app.
Comment: @Izzy so to run through SDK, you'd need to connect the phone through USB?
Answer: As my old electronics teacher told me, check the power then the physical connections before doing anything else....I have spent 3 hours trying various fixes on my phone, all to no avail. was working fine, then around the time of the most recent update it failed to connect (Hence software fixes searched for first). I finally thought I would try to clean the usb port on the phone...(compressed air had not worked) I had some copper soldering wick and a very small screwdriver, turned the phone off (Removing battery would probably be a safer bet in hindsight as well) and rubbed the copper mesh around every surface inside the port...works perfectly. Possibly many of the issues with using a different cable could be fixed the same way.
Answer: As usual, a factory reset is a possible last-ressort to sort things out and see whether the problem is software-related. And even if the problem remains, this way you don't need to worry about your data in alien hands :)
As a factory reset wipes all data (and 3rd party apps) from your device, you of course want to backup as much as possible, to be able to restore it later. Without root, this get's a little complicated -- but not impossible, if you're running Android 4.x. Since starting with ICS (4.0), ADB supports a Full Backup of non-rooted devices.
Which brings us to a seemingly chicken-and-egg problem: You cannot establish an USB connection, which is the most common pre-condition for an ADB connection. But fear not, there is a solution for that as well: You can connect Android with ADB via WiFi as well, and there's even a little app called WiFi ADB to help you with that1:

WiFi ADB makes it easy to debug/test your Android apps directly on device via WiFi TCP/IP connection. No need to use USB cable.

Trouble again is this requires root. Having a rooted device, you could of course also use Titanium Backup to backup your apps and data2.

USB connection broken, tried debugging