2-factor authentication everywhere: is this possible?

Question: I'm wondering if there is a way to require 2-factor authentication on webpages and Android apps that don't have it by default. I am already using a password manager but I feel that this may not be enough and would like to also have 2-factor authentication for everything I'm using, if possible. Or is this overkill?
Answer: For apps, you would need a custom ROM on the device to prompt for this. But the risk/reward balance is a little off for devices.
There are services that can be used to add MFA to online services for a single-sign-on account, but that adds it for that 3rd party account, not the individual services account.
You cannot add MFA to something that isn't expecting it. It's like trying to add another password. If the service isn't expecting it, then who checks it to verify it passed? Who blocks access if it fails?
Answer: Simply not possible. Software is created by developers. If developers don't write code to require 2FA, they won't support it. 2FA has a cost, depending on the type of framework that you use. Not all companies want to invest in 2FA.
Other than politely writing to app/web developers, there is little you can do.
You could use your password manager intelligently. The PM holds your password, which is complex enough you can't remember it. If the PM enforces some kind of 2FA, e.g. it's a remote service using OTP, or is a local app requiring both a password and a fingerprint, then you have most sort of what you have been asking for.
Comment: First part is absolutely correct, but you are loosing me with 2FA on PM. This has nothing to do with 2FA on the app it is a different security domain. Someone having your password can still use it no matter how you protect your PM. So this is not even "sort of" what OP is asking for, not even close.
Comment: It was meant to be a creative approach
Answer: The answer to your question is no, it is not possible outside the context of your own device, which makes no sense, it would look like you have less trust to your own device than anyone else's.
As for overkill, yes it is an overkill. If your passwords are strong and unique then not having 2FA presents only one risk, someone may gain access to the app/website that doesn't have 2FA and gather the data or impersonate you in the context of this app/website, but this is a risk you accept by signing up for any service that doesn't offer strong 2FA.
There is a light in a tunnel, OATH is getting a lot of attention from developers and most of the services that are used as trust providers offer 2FA. I often use login with google only to use google 2FA in case the application does not offer it. I have a separate email for this purpose only.
Answer: As all other pointed out, this is not possible. However, you could choose extremely random passwords and use a cool password manager like https://www.themooltipass.com/, which gives you at least real 2FA locally.


Is it permitted to desecrate a flag containing the shahada?

Question: I wouldn't desecrate a shahada for the sake of desecrating a shahada. But if a flag contained a shahada (for example Saudi Arabia), would it be forbidden by Islam to desecrate that flag?
Comment: I indeed approve these kinds of questions as you ask which can be so constructive for the readers... / God Bless You.
Comment: I think that a primary factor for an answer is; what is the intention of desecrating the flag which is containing the shahada?
Answer: You inquired about a nice inquiry. Yeah, seemingly it has the ruling of Allah names (and his Rasul (Apostle)), then it could be compared with desecrate a paper which consists of Allah names. consequently we ought not to desecrate it even if we do not its country or brand.


Why I have difference between DOS and BAND gap?

Question: As they advise everywhere, SKF should be considered without SOC, and already in NSCF, spin-orbit interaction should be included. But what is the actual question, as I know, band splitting occurs with SOC calculations and then the DOS that I take from SCF gives another band gap. How to deal with it?
Comment: What k-point mesh do you use for the DOS calculation and at which k-point do you find the valence band maximum in the band structure calculation?
Comment: @GregorMichalicek Hello
I use 28x28x28 k-mesh (I think that's enough :))))
VBM in band structure calc equal 3.6500 eV
Answer: The DOS and Band Structure normally use a different set of k-points and I will assume that is what happened here.  There are two possibilities for what we are seeing right now.
The first is that your lines for the band gap on both plots is not actually drawn correctly or aligned.  You should use what looks like Sumo to actually get a numerical value for both.
The second is that the DOS may not have hit the correct k-points to actually see the correct valence band minimum or conductance band maximum.  This would effect the DOS gap as well, showing it to be artificially too big.
Comment: I think it's some problem with aligned of graphics. Because accuracy of step in k-mesh is enough.


Can I enable my Realtek sound card without speakers plugged in?

Question: I have a computer (one of the Gigabyte Brix) running Windows 7. I don't actually need to hear any audio out of it, but some of the software I need to run doesn't work if it can't open an audio output device. With headphones plugged into the headphone jack it works, but with them unplugged the sound device is listed as disconnected and acts as if there is no audio device. The hardware is still there, so is there some way to just tell it to ignore whether speakers are plugged in and always enable that jack? I'd rather not have rely on leaving a cheap pair of earbuds plugged in.
Answer: Disable automatic jack detection by following the instructions in this thread. Relevant excerpts:

Open regedit with administrator privileges
Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E96C-E325-11CE-BFC1-08002BE10318}\0000\GlobalSettings
Change the value EnableDynamicDevices to zero.
Reboot

EDIT BASED ON COMMENT:
If the registry approach doesn't work, you have two other options:

Set the option in the Realtek Control Panel (should be available with latest Realtek drivers for the sound card).  Step by step details with images can be found at this website. Relevant excerpts:

Go to Control Panel -> Hardware & Sound -> Realtek HD Audio Manager
Click the yellow folder icon in the top right of the window
Disable front panel jack detection and auto popup dialog, click ok.
Click on device advanced settings at top right of window
Check the buttons for make front and rear output devices plaback two different audio streams simultaneously and tie up same type of input jacks..., click ok.
Open the speaker tab
Click on the green active speaker icon  (should be under back panel on right side)
Click set default, click ok.

Replace the Realtek drivers with Microsoft HD Audio driver.  Details can be found at this website.  Relevant excerpts:

Uninstall the Realtek audio drivers and reboot
Open the device manager
Under Sound, video and game controllers, right click on High Definition Audio Device and click Update Driver software
Click Brows my computer for driver software
Click Let me pick from a list of...
Choose High Definition Audio Device
Click yes when warning pops up.
Finish confirming dialog windows and reboot
Comment: My Realtek HD Audio Manager doesn't have the "front panel jack dectection" option because this teeny PC has only one audio jack, a hybrid speaker/headphone/microphone jack. I could have tried upgraded that driver in case I didn't have the latest version, but I just went with option 2 and switch it to the Microsoft driver. I expressly don't care about hearing the sound (since I'll have nothing plugged in) so I don't really care if it is a worse driver. With the Microsoft driver, *then* the registry setting worked perfectly.
Comment: That's definitely the kind of answer I was looking for. Unfortunately it doesn't seem to have had any effect for me.
Answer: If for some reason you can't disable the jack detection via software, keep in mind that the detection is done by a mechanical switch inside the jack.
Cut the plug off a set of unneeded headphones, and plug it into the jack to activate the switch.


make chipmunk leave the back yard

Question: I found that there are several holes, digged by chipmunk, in the back yard. Would you like to let me know how to handle these little animals, or how to push them move away from the yard? Thank you very much.
Comment: squirrel traps work wonders. they make live, and dead traps.
Answer: Te best and most effective would be to kill them, but not everybody likes to do that and there is some other option. You can plant some plants that chipmunks hate. The 2 best are narcissus flowers or daffodils. Narcissus is the best because the are toxic alkaloids and calcium-oxalate crystals in them (do not think it kills them). There is something called U scram 'cat and chipmunk deterrent', this is a cork tree that you put into the ground and releases a safe unpleasant order that they hate and they will go away. The only thing with this is that you might not like it yourself... one of these I think you will find useful. I like the plants because that is what I did and it seems to work pretty well. The other things is what my neighbors around the block did and they say it works well for them to. I did little some research on the flowers for ya. Hope that bug goes away.
Comment: Oh, I thought they were different. Embarrassed but thank you Kevinsky for that knowledge :)
Comment: daffodils are narcissus, same thing...https://en.wikipedia.org/wiki/Narcissus_(plant)
Answer: I have daffodils in my garden.  They do not repel chipmunks or squirrels.  They are not eaten by rabbits or deer in most circumstances due to the alkaloids in them.
Chipmunks will spend time in your garden if you are providing any combination of food/shelter/water.  If you remove or restrict access to the things they eat which include:

seed and nuts, bird feeders bring them in, acorns
fruit: strawberry, service berry, blue berry, haskap berry
when they are hungry in the spring tree buds, bird eggs
vegetables: tomatoes...

This site recommends these control methods:

live trapping and relocation. Keep in mind that at a typical urban density of two to four chipmunks per acre with territories that overlap an ongoing effort may be required.
remove areas of continuous cover leading to the area. Hedges, rock walls, tall grass provide cover that chipmunks use to conceal themselves
cutting grass short in the area you want to control
repellants such as  bitrex, thiram, or ammonium soaps of higher fatty acids can be applied to plants you want to protect.  They are labelled as squirrel repellents and must be reapplied after rain

I found this to be effective in the short term.  Hunting shops will sometimes sell fox or coyote urine.  Mark the perimeter of the area with this and reapply every few days. Unless they are really hungry most rodents will avoid areas where they smell predators.
Answer: Chipmunks live in woodpiles. I have never seen chipmunks except in places where there is a lot of dead wood lying around.
You can live trap them, but if you have wood piles, new chipmunks will just move into the vacant territory (Oh! Wow! An unoccupied wood pile, let's call U-haul and move the family in!).
Basically there is a simple strategy for getting rid of chipmunks: make sure you have no piles of dead wood or fallen logs near your house.
Comment: They are said to live in underground burrows. Do you have a link to substantiate your answer? Thanks
Comment: Yes, they live in burrows... under woodpiles. I realize you may be from a part of the world where there are no chipmunks, but it is absurd to start demanding proof about obvious facts about chipmunks. I live where there are zillions of chipmunks and I can tell you they live in woodpiles and I should not have to start citing scholarly papers to prove that. If you want to understand more about chipmunks read a book about them or something. I am here to tell the OP how to fix their problem, not write a monograph on chipmunk ecology.

make chipmunk leave the back yard


CodeCharge Studio alternatives for Mac?

Question: I'm a happy user of CodeCharge Studio but sadly it's the only reason to have a virtual machine with parallels, everybody here use a Mac. Does anyone know some other tool that generates PHP code and runs under OS X?
Answer: None that would be as good Code Charge Studio.
I run vmware fusion on my macs just for Code Charge Studio, and it's worth it to me until YesSoftware creates a mac version, hint hint.  I'd love to have it run nativity on my mac!!!
Answer: According to it's website, ScriptCase is usable through a web-browser.
The APEEL PHP Generator site has done some comparisons of other PHP Code Generators:
The reviews are pretty fair and cover costs, installation and some comments about generated code structure. Most of them, however, are Windows only.
Having said that, I also use CodeCharge Studio in VMWare on my Mac and am very happy with it in comparison to other tools. I work in both .NET and PHP projects and so the single tool for both (and switching between languages) is fantastic.

CodeCharge Studio alternatives for Mac?


Is it correct to say :He survived in a car crash. or should I say: He survived a car crash--without "in"

Question: I am wondering is it acceptable or correct to say "He survived in a car crash" since all the example sentences show that I need to cross out "in"--survive a car crash
Answer: The usual form is he survived a car crash, using the transitive meaning of survive: "4. (transitive) To live past a life-threatening event.."
Your alternative he survived in a car crash is grammatical, but odd and hard to interpret. It is using the intransitive form "1. (intransitive) Of a person, to continue to live; to remain alive," but an adjunct phrase such as in a car crash would normally be interpreted as meaning where/when/how he was continuing to be alive, not anything about the circumstances in which his life was threatened.
So for example, you might get something like He survived on the roof of his house, talking about a flood: the roof was not the event that threatened his life (the meaning of the object of transitive survive) but the circumstances where/when/how he survived.


What is the relation between probability of default and country's interest rates?

Question: Is probability of default expected to increase with increase in the interest rates set by the central bank?
Comment: One initial point: it matters what currency the country is borrowing in. For example, the Canadian government, borrowing almost entirely in Canadian dollars, faces far less default risk than a developing country that borrows in U.S. dollars. It would be useful to clarify what type of countries you are interested in.
Answer: The answer depends on the situation for the country in question. Since the answer is correspondingly very large if we covered all cases, I am only attempting to offer an overview of the cases. Feel free to ask follow up questions on more specific questions.
I will cover three important sinplified cases.

"Gold Standard"/"hard currency borrowing".
Free-floating fiat currency.
Euro area.

(1) The "gold standard" example is not currently of interest, but if you want to look at historical governmental defaults, they were associated with the gold standard, or the countries borrowing in a foreign currency ("hard currency"). (Countries in currency pegs are also in a similar situation.)
In a gold standard, the government's money in some sense can be converted into gold. Ultimately, it needs to have enough tax revenue in its local currency to force the private sector to turn in enough currency so that the consolidated government (fiscal arm/central bank) can honour the conversion parity. If that level of taxes is not politically sustainable, the government will be forced to default.
The usual operating procedure in a gold standard is for the central bank to raise interest rates to attract gold inflows. However, this raises the interest expense of the government, and so it makes it harder to sustain the gold parity price. So in this case, higher interest rates can raise default rates. However, the causality is ambiguous - the central bank is often forced to raise interest rates to defend the currency value, snd the currency is falling in value because of an expected default. Therefore, one could argue that high interest rates in a currency peg country are the result of an elevated default risk.
For countries with a currency peg or borrow in a foreign currency, they are in a similar boat, as they need to impose taxes in order to be able to obtain the external instrument.
(2) A floating currency sovereign (e.g. the United States, the United Kingdom, Japan, Canada...) does not attempt to fix the value of its currency versus external instruments. It can create arbitrary amounts of its currency unit without using any real resources. The only real concern is the purchasing power of the currency unit (inflation).
Since there are no external constraints (lack of gold), default is essentially a political decision.

There are operating procedures that might entail default (e.g. the debt ceiling in the United States). It is a political decision to not override those procedures.
Interest spending may be such a high part of the budget that politicians would rather default than pay the interest.
Government debt may be viewed as illegitimate. For example, debts incurred by a radical government that was later overthrown.

High interest rates might help push a country towards default, but that was not the case in the 1970s. The number of defaults of countries in this situation is so low and usually associated with other problems that there are almost no data to draw conclusions from.
3) The euro area is a special case: the currency itself is a fiat currency, but it is under the control of a central bank that is a supranational entity. The euro area nations are not sovereign in the same sense that the federal Government of Canada is, rather they are in a situation similar to a Canadian province.
Answer:
Is probability of default expected to increase with increase in the
  interest rates set by the central bank?

Not necessarily. The central bank's decision to raise interest rates may be sought to curb an overheated economy, to fight inflation, to reduce the prospect of currency depreciation, or to achieve other purposes. As you can see, these purposes have little to do with risk of default.


Accessing local filesystem in AWS lambda

Question: Is it possible to access local filesystem in a AWS lambda function? If so, is there any downside to doing so?
Answer: It is possible. I have python function that does something like
<code>  localFilename = '/tmp/{}'.format(os.path.basename(key))
  s3.download_file(Bucket=bucket, Key=key, Filename=localFilename)
  inFile = open(localFilename, "r")
</code>
Be sure you are using it for temporary storage and not to maintain any state.
Depends on what you are trying to do.
Comment: @kilokahn as per https://aws.amazon.com/lambda/faqs/ you get 500MB scratch space in `/tmp/.
Comment: @SquareRoot the local file system your function has access to is isolated to that function. Later invocations of your function may get access to the same files, but no other Lambda function in your account or any other account will be able to access those files.
Comment: Hi, Can anyone tell me the max amount of temp storage I get when using the /tmp folder in Lambda?
Comment: Yes. I was going to use it as intermediate storage similar to your example. Was not sure what kind of access rights we would have. Won't users be  able to copy malicious code into a shared AWS resource like this?
Answer: From AWS Lambda Execution Context:

Each execution context provides 512 MB of additional disk space in the /tmp directory. The directory content remains when the execution context is frozen, providing transient cache that can be used for multiple invocations. You can add extra code to check if the cache has the data that you stored. For information on deployment limits, see AWS Lambda Limits.


Why do ice cubes make a cracking sound when placed in fizzy wine (Prosecco)?

Question: When placing ice cubes in a fizzy drink such as Prosecco, ice makes a cracking sound, after which the fizzy bubbles more than usual. What is the physics of this phenomenon?
Comment: The photo will attract answerers..
Comment: How did the Prosecco get out of that bottle into the glass?
Comment: Not sure if there is anything special about wine, I used Prosecco but it may be that the effect is the same with soda. I imagine that the physics of the phenomenon would tell us if the effect is the same with all carbonated drinks. Thanks for the image.
Comment: What is special about wine in this respect? What happens if you use water at the same temperature?
Comment: @EmilioPisanty: I think as he has written fizzy drink. It may be containing soda water in it.
Comment: Some (IMO conflicting!) answers: [_Ask a Scientist!_](http://www.newton.dep.anl.gov/askasci/gen01/gen01518.htm)
Comment: Prosecco was poured into the glass first, once it settled the ice cubes were dropped in.
Comment: @Gugg quantum tunneling.
Answer: I think (although I cannot find any source for this that is even remotely reliable):

the cracking is due to a sudden temperature gradient being exerted on the ice, because compared to the ice, the wine is usually pretty warm. This sudden rise in temperature just on the outside causes the ice to fracture. This is accompanied by a cracking sound which is due to the sudden displacement (release of energy) of different layers of the cube during this fracture. I'm actually pretty sure this is at least part of the reason, because often when you throw in the ice, you can see fractures appearing in the ice at the same moment you hear the sound.
the increase in bubbling is due to there being more seed locations for bubble formation. Basically, this is true for most things you would throw in; bubbles tend to form best in places where there is an in-homogeneity of some sort; that's why they often form on particular points on the surface of the glass, and not just "somewhere in the middle" of the fluid. Throwing an ice cube in will drastically increase the possible number of formation sites, because ice cubes are usually pretty rough, microscopically speaking.


In OpenOffice.org Writer, how do I print page numbers?

Question: I would like to print a document with page numbers at the bottom. What is the easiest way to do this in OpenOffice.org Writer?
Answer: From OpenOffice Wiki:

Inserting a header
In OOo, headers are specified by page styles.

Open the Page Style dialog box for the desired page style (right-click > Modify).
Select the Header tab.
Under Header, check Header on and click OK.

Simple page numbering
The simplest case is to have the page number at the top of every page and nothing more. To do this, put the cursor on the header and select:
Insert > Fields > Page Number.
More complex variations
There are a lot of interesting variations that you can apply without further knowledge of page styles. Here are some suggestions:

Right-align the header to make the page number appear on the top-right:
Place the cursor in the header.
Click the Align Right icon (or right-click anywhere in the header and select Alignment > Right).
Add (type) the word page so the header reads page 1, page 2, and so on. This also requires using the Page Number field.
Add the document title so the header reads, for example: Joe's favourite poems, left justified, and page x with right justification, where x is the value of the Page Number field. Consider using a tab to separate the title from the page number.
OOo also has a Page Count field (Insert > Fields > Page Count). Using it, you could, for example, have a header that reads page 2 of 12.
Answer: Have a look at this thread.
It basically says that you have to activate the footer or header (in the page style properties) to tell OpenOffice where it has to put the page number.
I can't verify this at the moment as I am at work, however it's worth a try!


What are the best practices in quality assurance process measurement?

Question: How do you measure quality assurance and quality of products in your teams? What metrics do you use? What tools do you use?
Comment: I think a more specific question would help here (or a rephrase so it seemed specific enough for me to answer). Metrics is a huge area, and there are a million ways to measure the moving target of quality.
Comment: @user45: This is too broad for a Q&A site about "quality assurance". These sites work better when you have a very specific question you come across in your everyday work.
Comment: Agreed - its like asking "please list all possible good answers to questions in this forum".  *grin*
Comment: Agreed. Please specify a concrete question.
Comment: wonder if there are any best practices which fit all the shops
Comment: I agree this is too broad.
Answer: There are no "best" practices in my opinion.
As others on the internet stated before, there might be "good" or "good enough" practices.
But.
You have to see it in context.
One good practice which fits perfectly for your company, product, people, etc.. (~context), might be TOTALLY wrong in my company, product, people, etc. :-)
Also on the note of "metrics".
This can be a dangerous thing as well. Often you get, what you measure.
If I would be evaluated/paid by the amount of bugs, you can bet, that I would find dozens every day (or what ever the needed amount is).
If this would be "real" bugs or not.. wouldn't matter much for me (if my pay depends on it).
Also for developers: If you measure them by lines of code, you can bet you get dozens of lines, even when the function could be neatly fit in one line.
:-)


I want to install Debian linux

Question: So I'm thinking of switching from Windows 10 to Debian linux. Now I have a 32 gb usb but Im not sure what to do now, because I'm scared of ruining my laptop so I want to be 100% sure how to do this. I have downloaded the Debian ISO and I want to ask you, what should I do now to cahnge my OS from Windows to Debian. Thank you in advance!
Comment: For all I don't think this is a great question.  It's a very *well timed* question.  The instinct to stop, think, ask before doing something completely destructive is a very good instinct indeed.
Comment: At the moment this question isn't very easy to answer. There are considerations such as, do you intend to dual boot with Windows, or are you happy to delete Windows altogether? Furthermore, there is a lot of documentation on the internet that already answers this question, and we're not running a "let me google that for you" service here ;) You would be better off linking to the documentation you intend to follow, and ask about the specific points that you find confusing.
Comment: learn how to remove and install a new hard drive or SSD in your laptop, if that is possible with your model laptop.  That way you take your Windows 10 drive out and there's no chance of messing it up.  New disks or SSD's are not expensive.
Answer: If you're scared of this then this isn't the right time to switch.
There's several options that will let you use linux on your laptop without blowing away your windows 10 environment.  I'd suggest that instead of completely overwriting you pick one of the following options:

Download and install Oracle VirtualBox.  You can run linux as a virtual machine in a window inside MS windows. You can of course put the window into full screen mode.
Turn your USB stick into a bootable linux pen drive.  Eg: using PendriveLinux.  This basically uses the USB stick as a hard drive for linux, leaving windows completely untouched on your laptop hard drive.
Follow the debian instructions for installing, but instead of overwriting windows, resize the windows partition and create a dual-boot system.  If you pick this option then find out how to install windows 10 from scratch if it all goes wrong!
Comment: An extra dotpoint might be to use the Windows Subsystem for Linux?
Comment: WSL is great for overall Linux environment learning and experimentation, but VirtualBox is definitely what I'd recommend as a nondestructive means to try "living" in a new OS.
Comment: WSL can potentially kill your entire Windows installation, especially if you're a newcomer to Linux, so use with caution.

I want to install Debian linux


Can I buy an iPhone 5C in the US and use it in Ireland?

Question: I'm going to New York soon, and the iPhone 5C is just $99 USD. I am wondering if  an Irish SIM work or if I would have to get it unlocked?
Comment: Most likely if you see a $99 iPhone 5C it includes a 2 year service agreement with a carrier.
Comment: Would you link to the exact model you are considering buying? The unlocked 5c is your safest bet, and you'll discover that costs much more for several reasons.
Answer: When you buy an iPhone in America for $99 it's probably a SIM-lock together with an subscription. Here you can find the different iPhone 5S models. Search on the internet which Cellular frequencies are used by your provider, and then compare on the site I gave you which models you can use. Mostly the $99 models are locked for AT&T, Verizon,... providers only. So when buying an iPhone in America, make sure you check to model nr on the back of the package.
Answer: You can use your iPhone internationally. Just make sure you get one without sim lock (safest bet is an apple store)
It will cost you more than 99$ (That's the price you get with a 2 year contract).
And if you pay tax when importing to ireland, the device will probably cost you about the same.


What's wrong with this derivation that $i\hbar = 0$?

Question: Let $\hat{x} = x$ and $\hat{p} = -i \hbar \frac {\partial} {\partial x}$ be the position and momentum operators, respectively, and $|\psi_p\rangle$ be the eigenfunction of $\hat{p}$ and therefore $$\hat{p} |\psi_p\rangle = p |\psi_p\rangle,$$ where $p$ is the eigenvalue of $\hat{p}$. Then, we have $$ [\hat{x},\hat{p}] = \hat{x} \hat{p} - \hat{p} \hat{x} = i \hbar.$$ From the above equation, denoting by $\langle\cdot\rangle$ an expectation value, we get, on the one hand $$\langle i\hbar\rangle = \langle\psi_p| i \hbar  | \psi_p\rangle = i \hbar \langle \psi_p | \psi_p \rangle  = i \hbar$$ and, on the other $$\langle [\hat{x},\hat{p}] \rangle = \langle\psi_p| (\hat{x}\hat{p} - \hat{p}\hat{x}) |\psi_p\rangle =
\langle\psi_p|\hat{x} |\psi_p\rangle p - p\langle\psi_p|\hat{x} |\psi_p\rangle = 0$$
This suggests that $i \hbar = 0$. What went wrong?
Comment: To settle this apparent paradox, one must follow the path of functional analysis, just in the same vein that one discovers the beauty of GR in the proper mathematical setting
Answer: Both p and x operators as operators do not have eigenvectors in the strict sense. They have distributional eigenvectors which are only defined in a bigger space of functions than the space of square-normalizable wavefunctions, and which should be thought of as only meaningful when smeared a little bit by a smooth test function.
The normalization for $\langle \psi_p | \psi_p \rangle $ is infinite, because the p-wave is extended over all space. Similarly, the normalization of the delta-function wavefunction, the x-operator eigenvector, is infinite, because the square of a delta function has infinite integral.
You could state your paradox using $|x\rangle$ states too:
$$i\hbar \langle x|x\rangle  = \langle x| (\hat{x}\hat{p} - \hat{p}\hat{x})|x\rangle = x \langle x|\hat{p}|x\rangle - \langle x|\hat{p}|x\rangle x = 0$$
because $|x'\rangle$ is only defined when it is smeared a little, you need to use a seprate variable for the two occurences of x'. So write the full matrix out for this case:
$$ i\hbar \langle x|y\rangle = x\langle x|\hat{p}|y\rangle - \langle x|\hat{p}|y\rangle y = (x-y)\langle x|\hat{p}|y\rangle$$
And now x and y are separate variables which can be smeared independently, as required. The p operator's matrix elements are the derivative of a delta function:
$$ \langle x|\hat{p}|y\rangle = -i\hbar \delta'(x-y)$$
So what you get is
$$ (x-y)\delta'(x-y)$$
And you are taking $x=y$ naively by setting the first factor to zero without noticing that the delta function factor is horribly singular, and the result is therefore ill defined without more careful evaluation. If you multiply by smooth test functions for x and y, to smear the answer out a little bit:
$$ \int f(x) g(y) (x-y) \delta'(x-y) dx dy= \int f(x)g(x) dx = \int f(x) g(y) \delta(x-y)  $$
Where the first identify comes from integrating by parts in x, and setting to zero all terms that vanish under the evaluation of the delta function. The result is that
$$ (x-y)\delta'(x-y) = \delta(x-y)$$
And the result is not zero, it is in fact consistent with the commutation relation. This delta-function equation appears, with explanation, in the first mathematical chapter of Dirac's "The Principles of Quantum Mechanics".
It is unfortunate that formal manipulations with distributions lead to paradoxes so easiy. For a related but different paradox, consider the trace of $\hat{x}\hat{p}-\hat{p}\hat{x}$.
Answer: As it seems that you are not completely satisfied with Ron Maimon's answer, I'll put it in a bit different way.
The problem is that in your derivation you have a hidden ambiguity. $$\langle{\psi}_p\vert \hat{x}\vert\psi_p\rangle = \infty \;\;\;\;\; \Rightarrow \;\;\;\;\; \langle[\hat{x},\hat{p}]\rangle=...=(p-p)\langleψ_p|\hat{x}|ψ_p\rangle = 0\cdot\infty = \text{any number} $$
The problem is with the functions. Eigenfunctions of both momentum operator and coordinate operator are not really functions. They do not belong to integrable functions space and thus you can not freely work with them pretending that they are. Sometimes you can, but if you do at some point you find yourself in trouble.
If you take some "proper" function and do the math, you will find no problems. Let us take e.g. $$\psi(x)=\frac1{\sqrt{\pi}}e^{-x^2/2}$$
Then $$ \int_{-\infty}^{\infty} \psi(x) x\left( -i\hbar \frac{∂}{∂x} \right) \psi(x)dx = i\hbar \frac1{\pi} \int_{-\infty}^{\infty} x^2 e^{x^2}dx = i\hbar \frac1{2\sqrt{\pi}}$$
$$ \int_{-\infty}^{\infty} \psi(x) \left( -i\hbar \frac{∂}{∂x} \right)x \psi(x)dx = i\hbar \frac1{\pi} \int_{-\infty}^{\infty} \left(x^2-1\right) e^{x^2}dx = i\hbar \frac1{2\sqrt{\pi}}-i\hbar$$
The difference is what you expected.
If you take $\psi_a(x)=\frac1{a}\psi(x/a)$ and note that  $\lim_{a\to0}\psi_a(x) = \delta(x) = \vert x\rangle$ you will get an idea how this paradox for $\vert x \rangle$ may be solved and check that the solution is a correct way to handle $0\cdot\infty$. Similar trick may be used to resolve your paradox. Just functions which have $\psi_p$ as a limit are less convinient.
Answer: I think the paradox is from the fact that $\hat{p}$ is not a Hermitian operator in $x$ representation in the strict sense $ \langle \alpha |\hat{p} | \beta\rangle \neq \langle \beta |\hat{p} |\alpha \rangle^*  $ in $x$ representation.
Then we follow closely the action of $\hat{p}$, $ \langle x |\hat{p} |\alpha \rangle =-i\hbar \frac{\partial}{\partial x} \langle x |\alpha \rangle$.
$$\langle x | \hat{x} \hat{p}-\hat{p}\hat{x} |x \rangle =\langle x | \hat{x} \hat{p} |x \rangle -\langle x | \hat{p}\hat{x} |x \rangle=x\langle x |  \hat{p} |x \rangle +i\hbar \frac{\partial}{\partial x} \langle x |\hat{x} |x\rangle $$
$$=x (-i\hbar) \frac{\partial}{\partial x}\delta(0)+i\hbar \frac{\partial}{\partial x} x\delta(0)=i\hbar  $$
Comment: I don't think that's correct, instead of acting with $\hat{p}$ on the left you could act with  $\hat{x}$ on the right obtaining zero.    $$
\langle x|\hat{x} \hat{p}-\hat{p} \hat{x}| x\rangle=\langle x|\hat{x} \hat{p}| x\rangle -\langle x|\hat{p} \hat{x}| x\rangle= x \langle x| \hat{p}| x\rangle - x  \langle x| \hat{p}| x\rangle = 0
$$


QGIS: my styles don't appear anywhere

Question: I created a smart group in the Style Manager, but when I save a style (using "Save Style") in the layer properties window, the styles don't appear anywhere, either in the style manager or in the regular preset window. When I'm in the style manager and try to add a style, it forces me to recreate it. I must be missing something. How do I get my styles into the style manager?
Answer: Works fine for me in QGIS 3.26.3-Buenos Aires.
Save symbol in the symbology editor. Bearing in mind it's symbols you are saving. So if you wanted to save a categorised symbology you would save the style not the symbol.
When saving you should save to the default location. Unless you only want to use it for that one project.

Then it will show up in the Default styles, IF you have the correct filter on. By default only "Favourite" styles are shown.

It also shows up in the Style Manager under the label.

QGIS: my styles don't appear anywhere


A bunch of questions

Question: I've been using Ubuntu on and off (mostly off) since 11.10.
I'm probably not going to switch my main desktop to Ubuntu anytime soon, but I would like to use it on my netbook.
So here's the thing(s), it probably will work great except for some parts of which I'm not so sure about.
I'm aiming to use Ubuntu 14.10, the thing is my netbook is pretty weak, so I installed a Broadcom Crystal HD -70015(i think)- to make it play HD videos, and in windows after messing around with it for a while, it works great, I can watch 720/1080p video fluently which used to be impossible before.
Also since I replaced the wifi card with the crystal hd, I bought a usb wireless adapter (http://www.amazon.com/Edimax-EW-7811Un-150Mbps-Raspberry-Supports/dp/B003MTTJOY/ref=sr_1_1?ie=UTF8&qid=1416004534&sr=8-1&keywords=edimax+wifi)
Long story short is the Crystal HD card still supported in 14.10?
What are the exact steps that I  have to take in order to get it working? (fresh install)
Is my wireless adapter (linked above) supported?
Thanks,
Raif.
Answer: I don't know if the Broadcom Crystal HD is supported by the upstream Linux kernel, but Broadcom does provide drivers for Linux. I don't know if they work with the latest kernels though, as the site says >= 2.6.11, but the kernel in 14.10 is version 3.16.
The USB WiFi adapter you link to claims Linux support, but I do not know if drivers are included in the upstream kernel. It may come with drivers you will need to install or compile. If you already have one, check any CD that came with the adapter for drivers. Edimax also has a driver download available. Looking at the Edimax driver, it appears to be a Realtek RTL8188C/8192C chip, so may be supported by upstream kernel.
The best way to check, is to simply create a bootable USB installer disk, boot the live Ubuntu system, and see if your devices are recognized and work appropriately.
Comment: Thanks, but I already found the linux driver when I was looking fo the driver on windows. I did have the same concerns about wither it would work on newer kernals or not. Also I'm not really linux savvy, so I was wondering how to install such drivers. One more thing, I can't seem to make a bootable 14.10 usb, I tried unetbootin and universal usb installer, it seems like a common issue.

A bunch of questions


Extrapolating the meaning of a probability

Question: If I have 39% of students at a school that exhibit a specific, objective, measurable behavior, can I extrapolate this and say that any student at that school has a 39% chance of exhibiting that behavior?
Comment: If you are a Bayesian, your rationale is correct.
Comment: Thank you!  I didn't know what Bayesian was, but now I do!
Comment: I don't understand what this has to do with a Bayesian interpretation of probability.  Could you explain?
Comment: @rpz Can you explain your answer please? I can think of a number of ways the rationale could be incorrect for a Bayesian (and also ways it might be correct without being Bayesian); what assumptions are you making here for this to be correct if one is a Bayesian?
Answer: There is a 39% chance that a student selected at random from the entire population of students at that school exhibits the behavior.
Your wording/extrapolation is very slightly incorrect.
Answer: Let's say that the measurable behavior is gender. In other words, 39% of students at a school are female. If you picked out a student, let's call her Jill,  would you say Jill has a 39% of being female? No! She has a 100% probability of being female. However, if someone told you, "I'm going to pick a student out - what's the probability that they're female?" you ought to say 39%.
Another example, if someone told you they were going to pick out a student who has shoulder length hair - what is the probability that they are female? Your answer should likely be higher than 39% (since a large proportion of those with shoulder length hair are female).
In other words, knowing absolutely nothing about the randomly selected student, they have a 39% of being female. But if you knew some other information, the probability changes.


Magento 2 product import problem on windows 7

Question: I have tried product import with images on windows 7 using CSV file. It shows error "Imported resource (image) could not be downloaded from external resource due to timeout or access permissions in row(s)". I have set all permission on folders. May I know import products with images on windows 7 is possible?
Answer: The product images url/path which you are trying to update are not proper. Can you share some of the image values which you are trying to import, based on that I can suggest.
Comment: thanks for your reply. only images name put on csv file. I can use var/export or pub/media/import folder path.


Can we use the folded version of RNN in training?

Question: I always see that people teach the unfolded version of the RNN.

Do they do that just for the sake of teaching because the unfolded version is simple to explain sequence learning on it?
I read in an article before that it's hard to train the folded version of RNN. Why is that?
Do deep learning packages implement the folded or the unfolded version of RNN?
Answer: In short: there is no such thing as folded versus unfolded RNN. There is just RNN.
A graphical diagram of the RNN is simply an informal description of how an RNN model works. The folded and unfolded version of the diagram are just two descriptions of the same model. The folded version is a more compact description, whereas the unfolded version makes it more clear that the hidden state takes on multiple values over time. But they are describing the same thing.

However there is a very similar question which you might be asking, which is "must memory be allocated for the hidden state at each time step, or can i simply overwrite the hidden state at the last time step with the hidden state of the current time."
The answer to this is: training the model via backpropagation requires access to the value of the hidden state at every time step, so all previous hidden states must be stored in memory. This is just a fact of backpropagation. On the other hand, during inference time, it's no longer necessary and the hidden state can overwrite itself, saving memory.
Comment: thank you for your answer. the reason why I asked is because I read this article [rolling-and-unrolling-rnns](https://shapeofdata.wordpress.com/2016/04/27/rolling-and-unrolling-rnns/), It says that unfolding the RNN made the back-propagation easier. (you can just read the last 3 paragraphs). And also in here [RNN unrolling](https://machinelearningmastery.com/rnn-unrolling/#comment-494291) it says "the backward pass requires the conceptualization of unfolding the network"
Comment: @floyd i see. maybe it's just me being a bit pedantic, but i like to separate the implementation of RNNs from how they're drawn, to avoid having to "conceptualize" anything.


Why is Naked Lunch by Burroughs so groundbreaking and recognized as a literary milestone by prominent authors that succeeded its publication?

Question: Why is Naked Lunch by Burroughs so groundbreaking and recognized as a literary milestone by prominent authors that succeeded its publication? I've recently finished it and although I found it fascinating and very articulate at times, I fail to see any profound themes or literary significance that could be drawn from it.
Answer: Burroughs' Naked Lunch presents the challenge of having woven some very significant themes and social commentary up in a fragmentary and obscene narrative written in a disorienting style. Some of these profound themes & literary significance include:

Power, including state & governmental power, bureaucratic power, the power of biology to determine one's life, the power of addiction and sex, and the power of and over death. All of these get intermingled in a way that at the time was quite fresh.
Style: The book is written in a style that is intentionally colloquial and intentionally that of the outlaw. This really alienated the general middle-class American reading public at the time - not only was the book offensive, but it seemed to be written in some sort of dangerous code. Again, at the time quite sensational. Additionally, the non-linearity was much admired by numerous artists and authors and later appropriated in various ways.
Sex, vice, and violence: the novel has  quite radical presentations of this subject matter for the time, including homosexuality. It was actually the last (text-only) book to be banned in America (banned in MA, then overturned in a rather significant court case, adding to the book's influence).
Satire: Certainly there is debate about which parts are satirical and which are not, but, for example, the political parties of Interzone satirize both our own political parties and the ways power and influence are conceived politically (mind-control, clones, eradication).
Social commentary & critique: The characters in the vignettes are largely satirical, and the vignettes themselves are often an intentionally hyperbolic gloss on American cultural attitudes towards sex, drugs, legality, and the status quo, written using various bastardized American dialects and discourses.
Philosophy: This book has, rightly or wrongly, provided a fodder for a number of philosophical positions, perhaps most notably the work of Gilles Deleuze and Felix Guatteri .

This list could go on, but these are the most salient ones to mention. If you ever look at the reasons authors, artists, and scholars give for citing Burroughs' Naked Lunch as an influence, you'll note the disparate range, everything from "I, too, like drugs" to "He changed the way I conceptualized the relation between the human mind and body."
Sixty years later, some of the novel's impact has faded, arguably because of the influence it had on other anti-establishment authors and artists, and arguably just because 60 years on, especially post-Vietnam and post-internet, social protest and the proliferation of "obscenities" are more mundane. It's definitely a fascinating book, and very articulate, as you said, but to what end? I'm not convinced Burroughs had an end in mind when he wrote (in spite of what he may claim in interviews), and that ultimately it's the brazen strangeness (for want of a better word) of the book that has acted as an influential and productive source of inspiration for some people.

Additional Reading, if you're interested:
You also used the word "fascinating" - there is a very good book called William Burroughs and the Secret of Fascination by Oliver Harris that focuses on precisely what you ask about, covering what lead up to Burroughs' writing of Junky and Naked Lunch and the books' relation to America that lead to their volatile and influential reception.
Burroughs also further develops the themes in Naked Lunch to an extreme degree in The Soft Machine, Nova Express, and The Ticket That Exploded (the cut-up books). Then Burroughs  refines them into a more readable, cohesive form in Cities of the Red Night, The Place of Dead Roads, and The Western Lands.


What does it feel like to be cloned at the beginning of the day and merged at the end of the day?

Question: In my mad scientist lab, the scientist has a machine that makes a very high quality (atomic level) scan and clone of himself. The problem is, it takes some hours to work, so the mad scientist sleeps in the machine. He doesn't want his clones to develop an identity of their own, so every night he freezes his old clone, merges their experience into his brain, and reclones himself. This all happens while he is asleep. So when the scientist wakes up, there are almost identical brain states present in both the real scientist and the clone. What are the psychological effects of wake up every morning and asking: am I a clone? Is there anyway to intrinsically "know" you're a clone? Or do you just have to prepare yourself to compare where you fell asleep from last night to where you woke up the next day? Would the clone feel upset about being frozen every evening? Or would he recognize that this is just another form of sleep from which he will awake?
Comment: One more thing. (d) Without explaining in detail the psychology of your mad scientist, this Q is ***impossible*** to answer. Nine billion people live on this planet and every single one of them will have a unique experience to the conditions you've described. That makes the question in need of additional details, opinion-based, too story-based, and in need of more focus. (Click on the "Close" link to see more about VTC reasons). I'm trying not to cast a close vote myself - but please take the time to read our rules explaining how to write a good question.
Comment: This seems highly dependent upon how cloning works in your world. Since you don't describe the cloning process we can't help you figure out what the process will feel like. Please also remember that character driven questions are off topic for this site. We also have a strict one question per post policy.
Comment: Hello Jacob, welcome to worldbuilding. You have two close votes. To avoid your question being closed (a) You're allowed to ask one-and-only-one question (you're asking 6 questions, related or not). (b) Qs cannot be hypothetical (by definition, asking about an experience no human has ever had and won't in the known future is 100% hypothetical). (c) Qs that can be reasonably answered with a book-length answer are off-topic (this could realistically be answered by writing an entire book). Please take the time to read [help/on-topic] and [help/dont-ask].
Comment: My main confusion with this is "merges the experience".  If you had hamburgers and your clone had french fries, which do you remember having for lunch yesterday?  Do you remember two yesterdays one after another - if so, which one was first?  Also, why doesn't the freshly made clone know it because he's in a nutrient tank, lacks a belly button, has part falling off where the 3D printer had a slight warping problem, etc.?
Comment: This is a classic question in philosophy of identity. Suffice it to say: there is no consensus, and precious few facts we could appeal to for help. You will have to decide how your character experiences it. I'll just add that it's one hell of a handwave to flatly assert that he merges their consciousnesses into his own.
Answer: They're both real
If they are identical they can both see themselves as the "real" mad scientist. There's no need to reclone at the end of the day because the clones can resynch their experiences to the same effect. Both mad scientists wouldn't see a problem because the very concept of merging experiences implies a dualist philosophy meaning that the body is merely a vessel for the mind. As long as they become a singular conscious at the end of the day they would think of the other body as an extension of themself.
If you are really keen on recloning, rather than picking the "real" mad scientist they would choose the mad scientist in better physical condition. In fact, clones should be made from a body that is kept in stasis so the mad scientist is always young and healthy. You could pig out and eat a box of doughnuts every night without gaining weight or feeling sick afterwards! Get drunk without the hangover! You can do whatever you want knowing tomorrow your body will be literally brand new! Yay cloning!
Comment: 'Freezing' the real body is a good idea. The clones would be frozen each night, their memories copied to the real one, and then redistributed to the bodies of the clones(no sense in wasting good bodies each night. Repair the bodies and/or replace the brain)
You could even try to keep it a secret which clone is the clone. Lock down the memories where they know the actual body is frozen (keep a file ICE), and make them unknowing of which body is the clone. They both know they might be a clone but depending on their personality, might not want to find out or find it inconsequential.
Answer: Jump cut
If the scan is a perfect copy you have a problem. It is impossible to tell if you are the clone. The only thing that links you to the past and a continuous sense of self is you brain functionality and your memories. You are you because you think like you and you remember things that happened to you in the past. The clone meets both of these requirements, and therefore is you.
Unless the clone is in a place it knows the clone should be, it must assume it is the original. The experience would either be a jump cut if the scan happens when the subject is awake, or waking up someplace new half way through a dream if it happens during sleep.
If someone switched the bodies halfway through, then the original would think they are the clone and the clone would think they are the original, and there would be no difference either way.
The "mauler twins" a pair of clones from "Invincible" is a good example of this. "Soma" is also a good video game example of cloning consciousness.
However, if the process takes hours there could be an issue. Fluctuating signals in the brain occur incredibly quickly, so a "scan line" could form, where the scan doesn't capture an adequate slice every time it measures the brain, leading to residual error. This could be detected with proper instruments.
Answer:
It feels great, it feels great, man

More as a comment.
"... develop an identity of their own,..." - too late, if one is not sleeping and free to wander around, he knows he is a clone, as he knows what original knows (atomic scans is not enough for that, you have to preserve signals in the brains, but considering that magic merging back(which is far from trivial) I assume tech is quite advanced so it makes a good clone)
Fist of all the questions you ask, most of it, are result of subjective perception, unique to each individual. And here are bad news, "He doesn't want his clones to develop an identity of their own ... so every night he freezes his old clone, ..." - not a great situation, and I would not recomend cloning to a subject with such attitudes. But it rather your problem, as author of the idea, who didn't ironed details of it, and does not understand the situation fully, than a problem of a mad scientists, who developed(assuming) quite advanced technology, and had years(assuming) of mental preparations and changes and problems to solve.
This technolgy is more suitable for people who, mm let's word it in this way - inclinded to sacrifice themselfs for a greater goal/good. Then deviations of expirience, for a day week month do not matter that much. But there always a chance of a fork go wrong.
One of the problem in this situation, quite fundamental one, is that this cloning process creates not a copy of intelligence, but a whole human. This fundamental fact leads to many problems of all kinds, one of which is that rigth after the creation, previous history does not matter and rigths of a human extend on that clone - because he is a 100% human, no matter the way he is born.

there are ways to make digital copy with non human body and then it is not a human.(not inferior, not superior, just not a human - it has its cons and pros)

Another problem, at least of the q as it worded - there is no goal or task for such process, such cloning. It more just an existence, not a problem solving. Once it is a problem solving or goal or a purpose - there is a way for a clone to tell when it is done. Once it is done, as an example building secret underground fusion reactor ITERv332 - once you dig that underground cave of that size for a week, initial excitement for the idea is gone, you sure want to go "sleep" on your own. Or writing an paper for arxiv, or...
With just existance things are different, it can be a goal in some cases, last survivial clones himselfs again to continue, idk there can be all kinds of goals or things to do, including things like in Highlander's. Meaning independance and surviving of the fittest (in this case Montecarlo maze of expirience - where one gets most fittest expirience)
So do not be so boring as killing a clone each day, be more like Rick cloning himself freely, and whatever when it suits some goal, and make colliseum of death when time comes.
A clone can take endeavor with 10% survivial chances - whatever he dared not to do before, whe  it was just one body. And expirience of this kinds is accomulated by main body. Expirience of that kind, there once in 3 month a clone has it twice. For a clone the interest it - next time he wil be cloned he will be smarter, more expirienced and all that.
So knowing that one is a clone may be releasing shakles than some mind shattering expirience, which seems to be a theme of movies of that kind.

having some rules between clones themselvs may help, but that a different topic

Making it up always as a problem - it means looking at the opportunity from a bottom of a well. Alterd carbon tv-series was not bad in this regard, in essence they all are clones, and no one is bothered that much by that, even if authors were to shy continue by eleminating cooperative(or not) groups of clones of the same person.
All in all, the way it formulated in q that cloning is useless, but there are ways to make it meaningfull with or without killing clones each day.
All the clone subjective q's are in realm of psyhology, and answers are different for different people. Some ppl can use this opportunity some will be less effective, but it hard to screw the situation if cloning technology is good(if it not good enough it still some sort of mini evolution situation, and can't be considered as fail)
So be less conservative and look more for channels with excistencial content, expand your perception of what humans are capable of, and they are quite capable.


Older Zenith motion activated flood light not working properly

Question: I have a Zenith 2 light (halogen) flood light that worked fine until a couple of months ago when we needed it most!  There was a guy in our driveway in the middle of the night casing our cars.  Our cameras picked him up but the flood lights did not and have since not worked.  When I turn them on they stay lit (20 minutes in this case) as set.  When I approach the sensor at night the little red light flashes as if it's picking up motion but the lights do not turn on.  Should I just replace the unit or is there another fix?  I have the same set-up on the back of our house and it's worked fine for many years.  I have the setting set the same as the light on the back of the house.  Only difference is that the problem lights are switched on every evening as they are wired with other outside lighting
Comment: Hello, and welcome to Home Improvement. Have you re-checked the settings for the motion sensor and lights? And, you should probably [take our tour](//diy.stackexchange.com/tour) so you'll know how best to participate here.
Answer: Replace the Fixture
In this particular case, since the red light flashes, it sounds like the sensor is OK but it isn't activating the relay for the light. But on an older halogen unit it is not worth repairing - just replace it with a new LED fixture. The electronics do wear out over time, especially with outdoor fixtures, and you will save money on electricity with a new LED fixture.
Look at the existing bulbs to find the power (watts) used and then translate that into an equivalent LED. For example, if your existing fixture has 2 x 100W Halogen bulbs, that is roughly 2,000 to 2,500 lumens according to this chart. Replace it with a new fixture like this one picked at random from Home Depot and you get 2,400 lumens for 26W. At 0.13/kWh (average US according to a quick search), saving you $8.25/year for each hour/day that the light is on (motion detected -> lights actually on; the motion detector (old or new) uses very little power).
Comment: Thank-You, was hoping for a smoking gun. Will just go with this answer and also replace the other one that's still working.
Answer: Generally on motion sensors of that era, the motion sensor device and the lights are separate pieces of equipment. The motion sensor can be replaced separately.
That would still leave you with a clunky old incandescent motion sensor, but they aren't on very often. Besides, nothing keeps you from changing the bulbs to LED. Make sure to select a motion sensor module that's LED friendly.


Missing verset in Psalm 15:3

Question: The verset ". . .slanders not with his tongue" is missing from the Psalm (15,3) found at Qumran. The LXX does contain this reference to slander which begs the question, at least for me, when would this have been added post-Dead Sea Scrolls?
Comment: Which scroll of Qumran DSS are you talking about? (There are several).  Whose to say if the DSS deleted the verse rather than adding it later on?
Comment: I did find a reference to Psalm 15:1-5: Manuscript - 5/6HevPs; Location - 5/6Hev 1b. These were referenced in a text, The Biblical Qumran Scrolls, by Eugene Ulrich, but I failed to find the actual Hebrew associated with this location having downloaded the .pdf. I'll try and do some more digging.
Comment: I did find, under the Leon Levy Dead Sea Scrolls digital library, fragments belonging to the above 5/6Hev 1b (https://www.deadseascrolls.org.il/explore-the-archive/manuscript/5_6Hev%201b%20891-1). But narrowing my search to the Plate/Fragment in this collection will be another challenge.
Comment: Does this answer your question? [How reliable are the Dead Sea Scrolls as a base to compare against the Masoretic text and the LXX?](https://hermeneutics.stackexchange.com/questions/4032/how-reliable-are-the-dead-sea-scrolls-as-a-base-to-compare-against-the-masoretic)
Comment: The minor variants can be explained by the same reasons we have differences in NT mss. This kinda questions requires reading of textual criticism and history of Heb text. The other old questions have given some resources for it. Scribes can add words and phrases for many controversial and innocent reasons.
Answer: The truth may sound strange to those accustomed to revering the Dead Sea Scrolls, but the real issue here is most probably with them, not with the earlier manuscripts--consider the evidence before judging.
Important Evidence for Dead Sea Scrolls' Origin
The Hebrew scribes who copied the scriptures were fastidiously careful to preserve them without making any change whatsoever to the text.  They would not change so much as the spelling of a word, even if they deemed it to have been misspelled.  For this reason, we are able to see evidence today of the evolution of the Hebrew language over time, as spellings changed and Aramaic words or spellings sometimes entered the language.
At the time that the scribes were copying the scrolls discovered in the caves of Qumran, now called the Dead Sea Scrolls, they were using more than one scribe for each manuscript.  The name of God in Hebrew, often transliterated to English as YHWH, was regarded as so sacred that a special scribe was designated to write it--a separate scribe from the one who had copied the other portions of the text.  The first scribe would leave a blank space wherever the name of God should be, and the special scribe would later fill in the blank.
In many of the manuscripts discovered at Qumran, this step of filling in God's sacred name was not completed.  So we know that at least these manuscripts were not considered "perfect" at the time of their burial.  And it was a burial--a sequestering in the caves, much like Jesus was "buried" in a hollowed-out cave closed in by a large rock.
Even a very small change meant the manuscript was unfit to be used and must be taken out of circulation.  Dr. Patrick Zukeran (2006) writes:

After years of careful study, it has been concluded that the Dead Sea
Scrolls give substantial confirmation that our Old Testament has been
accurately preserved. The scrolls were found to be almost identical
with the Masoretic text. Hebrew Scholar Millar Burrows writes, "It is
a matter of wonder that through something like one thousand years the
text underwent so little alteration. As I said in my first article on
the scroll, 'Herein lies its chief importance, supporting the fidelity
of the Masoretic tradition.'"{6}
A significant comparison study was conducted with the Isaiah Scroll
written around 100 B.C. that was found among the Dead Sea documents
and the book of Isaiah found in the Masoretic text. After much
research, scholars found that the two texts were practically
identical. Most variants were minor spelling differences, and none
affected the meaning of the text.

Those "minor spelling differences" were enough to disqualify the manuscript, and its removal from the copy chain meant the preservation of the original text via those copies which were error-free.
The scribes regarded the copied scriptures as so sacred, that even when they had made a mistake in copying them, they dared not destroy, mutilate, or burn the manuscripts.  They, instead, gave them an honorable burial.
As one documentary-style article posted to the Live Science website states:

Destroying any text that contains God's name is forbidden in Jewish
religious law, even accidently, and any documents from Cairo's Jewish
community were ultimately stored in the genizah just in case, at least
until they could be formally buried.

The fact that these scrolls were buried in such a remote place seems to support the theory that they were not intended to ever be rediscovered or accessed.  They were not buried for the primary purpose of preservation, but to hide them away, never to be seen again.
The Usefulness of the Scrolls
The Dead Sea Scrolls have much to teach us.  They were a wonderful discovery.  But they are unsuited for use as a standard of measurement or of accuracy for the Biblical manuscripts known prior to their discovery.  They had flaws, which is why they were taken out of circulation and buried in the caves.
Over time, as the scribes did their work of copying, their "originals" would wear out, and they would begin to use one of their fresher copies as their new "original."  Manuscripts taken out of circulation, however, and stored in earthen vessels where they would last a long time, did not wear out.  Carbon-dating may well show them to be "older"--but this does not mean they are more "original" nor more accurate.  Many scholars today presume that older is always better: but this is simply incorrect.
Conclusion
In place of asking, "when would this have been added post-Dead Sea Scrolls?", the question might better be asked, "Is the absence of this phrase in the manuscript the reason it was buried at Qumran?"
It was the minor deviations from the source material that prevented these scrolls from entering the general circulation, and instead got them set aside, not to be used.  Out of their enduring respect for the holy scriptures, the scribes dared not destroy them, even when flawed, but gave them an honorable, and perhaps ceremonious, burial in the caves.
Comment: @Michael16 An additional fact that would add evidence to this is that the Book of Esther, the only book of the Old Testament that does not mention God's name, is NOT among the Dead Sea Scrolls.  Interesting, right?
Comment: I doubt your claims about the DSS being discarded rubbish is real and supported by real scholars. They were carefully buried or kept in the isolated caves as a treasure to save them from destruction from the Roman attacks. The discarded books could have been buried in synagogue and other places, not on mountain caves.
Comment: @Michael16 As it happens, I was just in a Hebrew class this morning in which the Jewish rabbi was talking about the sacred name of God and how the Jews regarded it.  He asked the class what happens if you write that name down somewhere--can you now just throw it away or destroy it?  "No," he said. "You give it an honorable burial."  Now, he was not talking about the DSS. He was talking about God's name. But scripture is full of God's name, and those DSS would be treated as sacred because of that name, even if they had flaws. They could not be discarded as a common thing, but buried honorably.
Comment: Thats not a burial. The discarded mss are buried in synagogues and regular places. This is deliberate hiding for preservation. You are making conjectures of your own based on the tradition of discarding erroneous mss. It wouldnt be surprising that censoring of God's name did not begin during the DSS time. Try to use on reliable sources with reference, no conjectures.
Comment: @Michael16 Per your definitions of "burial," was Jesus buried?
Comment: you are just advised to use reliable sources in your answers.
Answer: In your question, it seems as if you are giving a proven amount of weight to the DSS. There are some problems with that:

There is no evidence that the Qumran documents were "mainstream":

The Dead Sea texts used and preserved by the Qumran community include
a number of textual types. Even among these traditions the variations
are minor, and there is no evidence that such texts were circulated as
standard texts in main-line Judaism.
—Brug. Textual Criticism of the Old Testament (p. 58)

The DSS that were copied more faithfully end up confirming the MT:

Many of the DSS texts are rather carelessly copied to the degree that
they would not have met the rabbinic standards for the maximum number
of corrections allowed in a manuscript. Parts of the Great Isaiah
Scroll have corrections every four lines of so. The rabbinic standard
allowed only one to three corrections per column.
—Brug. Textual Criticism of the Old Testament (p. 59)

The textual streams within the DSS conflicted with each other. And the variants are "substantial":

The Qumran texts, as well as differing from one another, relate to
ð, ð, ⅏, and the other texts in a ramified system of agreements
and disagreements. The more significant deviations from ð in the
Qumran texts are described in ch. 7B1, 4, 9–13, 18, 22, 23, as well as
below.
Some texts exemplified by 1QIsa in Table 22 display a great number of
differences in orthography and morphology, whereas the relation is
reversed in the texts exemplified by 4QSam in Table 23: differences in
morphology and orthography are few, in contrast to the large number of
other types of differences in both major and minor details. Most of
the variants listed for 4QSam in Table 23 are substantial.
<Emmanuel Tov, Textual Criticism of the Hebrew Bible, 3rd ed.
(Minneapolis: Fortress Press, 2012), 105.>

Conclusion:  Before one uses the DSS as a witness (just as in the LXX), one first has to do thorough text criticism on the DSS to see if, in the specific case, it is actually a viable witness.  So, there's no evidence to  give the DSS preeminence over the MT in Psa. 15.
Further Consideration:  If, in this instance, the DSS were of more valid weight, we would likely see some sort of trail of transmission. There would be some sort of reading elsewhere than in the DSS. Instead, all the versional support we have leads us back to the MT:

"ὃς οὐκ ἐδόλωσεν ἐν γλώσσῃ αὐτοῦ" (Psalm 14:3 LXXS-T) ("who does not deceive in his tongue")
"Qui loquitur veritatem in corde suo," (Psalm 14:3 V-LATINA) ("who speaks truth in his own heart")
"loquiturque veritatem in corde suo" (Psalm 14:3 VULG-T)
"ܘܠܐ ܢܟܘܠܬܢ ܒܠܫܢܗ." (Psalm 15:3 PESHOT-T) ("Who is not deceitful in his tongue.")

Final Conclusion: With all this considered, it's far more likely that, in this instance, the DSS made a mistake which the MT (and all the versions) didn't.

Missing verset in Psalm 15:3


Testing upgrade to PHP 7

Question: I have upgraded to PHP 7.1 on my local dev environment and my Drupal 7.59 site with CiviCRM 5.1.2 seems to be working just fine. I can't find any issues. I am wondering if there is a way in the CLI to check the compatibility of all enabled contrib modules or if I need to look each one up and/or just test extensively to see if anything isn't working.
Answer: At this point assuming your site doesnt make use of extra modules, you can likely assume 7.x php works fine. I have found in numerous sites in the last few months that moving to php7 went fine and most php 7 were squashed in popular D7 modules in the last year or two.
If you have alot of custom modules you could try running a php 7 linter from github to check modules for php7 related issues, rather than trying to live-test drupal itself.
Something such as this github repo:
https://github.com/wimg/PHPCompatibility

Testing upgrade to PHP 7


How to show it is contained in a convex hull?

Question: There are $(d+1)f$ points (denote the set of all points as $S$) in $\mathbb{R}^d$, that can be divide into $d+1$ disjoint sets $F_1,...,F_{d+1}$, each set of size $f$. If we have
$$
\mathcal{H}(F_i)\bigcap \mathcal{H}(S-F_i)=\emptyset
$$
for all $1\leq i\leq d+1$. How can we show the following:
$$
\mathcal{H}(S)-\bigcup_{i=1}^{d+1}\mathcal{H}(S-F_i)\subseteq \operatorname{conv}(v_1,...,v_{d+1})
$$
where $v_i\in F_i$, $1\leq i\leq d+1$
Comment: The question seems to make sense if $\mathcal{H}(X)$ is the convex hull of $X$. This isn't quite redundant with $conv(v_1,...,v_{d+1})$.
Comment: What does $\mathcal H(\cdot)$ denote?
Comment: Yes, $\mathcal{H}(\cdot)$ denotes taking the convex hull.
Answer: $\def\conv{\mathop{\rm conv}}\let\emp\varnothing$This is the answer if @Douglas Zare is correct, so that  $\conv(\cdot)$ means the same as $\mathcal H(\{\cdot\})$.
We omit the condition that $|F_i|$ are the same, thus considering any disjoint finite sets $F_i$ with $S=\bigcup_i F_i$. Notice that we may keep only those points of $F_i$ which are the vertices of $T=\conv S$; this just makes the claim sharper. Due to the compactness reason, we may assume that the vertices of the dual polyhedron of $\conv $ are in general position; thus every $d$ vectors connecting a vertex of $\conv S$ with other vertices are independent.
If $|F_i|=1$ for every $i$, the claim is trivial. So assume that $|F_1|>1$. In this case, since $F_1$ is separated from $F_j$ with $j>1$, there exists an edge $uv$ of $T$ with $u,v\in F_1$. This edge belongs to some $(d-2)$-dimensional face $P$ of $T$ which is a part of a $(d-1)$-dimensional face $Q$.
Now rotate the hyperplane spanned by $Q$ around the affine subspace defined by $P$. Let $w$ be the first vertex we meet. Then the hyperplane $\alpha$ spanned by $P$ and $w$ separates some vertex of $Q$ from the rest vertices of $T$. Then $\alpha$ contains the vertices of at most $d-1$ of the $F_i$ (since it contains two vertices from $F_1$), so the whole simplex it cuts out of $T$ is contained in some $\conv (S-F_i)$. Now we may remove this vertex and proceed by induction.
Comment: Thank you for the answer. However, I am not quite follow... Why is the claim sharper when only considering vertices of $T$? Since $conv(v_1,...,v_{d+1})$ could be smaller without this condition. Besides, where did you use the condition that $\mathcal{H}(F_i)\bigcap \mathcal{H}(S-F_i)=\emptyset$?
Comment: 1) The claim is sharper, since $\mathop{\rm conv}(S-F_i)$ becomes smaller in this case. 2) The condition of non-intersection was used in the middle: all vertices of $\mathop{\rm conv} S$ belonging to $F_i$ form a connected (by edges) set, so there exists an _edge_ with the vertices of the same color. In turn, this condition is needed to establish that the simplex to be cut is not polychromatic.


How do chess openings officially get recognized?

Question: With so many combinations of moves possible, how do openings get recognized? For example, what is to prevent me from playing a series of moves and declaring it the xaisoft gambit or xaisoft heart-attack?  What organization officially recognizes openings?
Answer: There's no organization that officially names openings.  Generally, the first person to publish professional-level research for a sequence of moves gets to name it.
Many openings with modern names were first played 200 years ago.
Answer: An opening is named after successful professional USE by a world class player, in world class events.
Many "openings" are played by amateurs, either accidentally or on purpose, that don't get names. But if a line is played in high level tournaments by X, and X wins a large percentage of his games, people come to recognize it as X's opening, and name it after him or her.
Answer: You don't need to publish it professionally to have an opening named under you.
Take the example of the recently played Grunfeld defense in the game 1 of WCC 2012 Anand vs Gelfand.
It's a little-known fact that the first person to play Grunfeld defence was a Moheschunder Bannerjee in 1855, but because Ernst Grunfeld used it to stun Alexander Alekhine at Vienna in 1922; hence, the opening was named after Grunfeld.
If you end up using it in a popular/famous duel then also it can be named after you.
Comment: Correct.  If you're a leading GM and play it in a tournament, then that can happen.  I believe that qualifies as publishing professional research.  Besides, who would have the brass to say, "Look at this move by GM X! I name it after ME!"   A person doing this would be mocked.  Now, if the opening gains no further attention for many years, then it can be done.


Staking Pools, How do they work? what are their machanics?

Question: How do nomination pools work in the system, what are the mechanics and who controls the direction of those nominations? what are their mechanics?
Comment: Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
Answer: Found information about pools in the website for those asking same question.
https://wiki.polkadot.network/docs/learn-staking#4-rewards-mechanism
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


Need finishing tips for 50 yr old semi rough sawn wood paneling in a living room

Question: Looking for finishing tips for old semi rough sawn boards in a living room.
The wood is very dry and not very attractive as it sits now and I do not want to polyurethane it.
Any suggestions?
Comment: Well even gloss varnishes when thinned heavily penetrate well and don't give a decent gloss until multiple coats have been applied. But regardless of that, they make matt versions of most varnishes and waterbased finishes if you want a fully matt final surface. Matt waterbased poly might be a great option for you here.
Comment: I'm sorry but this is a bit too broad for here. Why don't you want to use polyurethane? It's one of the best finishes going, and one of the most versatile.
Comment: I was not looking for a glossy type of finish, more of something to show the wood without a shine
Answer: I just made a mantle out of an old barn beam.  I used a wire wheel first, then sanded with 80 -> 120 -> 220 sandpaper using a random orbital.  Wiped with mineral spirits and then two coats of tung oil, lightly sanding again with 220 between coats.  It has a nice matte finish and tung oil doesn't build a film like poly does.
Sorry for the blurriness, it's a screenshot from a video I took.


How to remove password lock on WD mybook 1TB

Question: How do I disable the password lock on my My book 1 TB, I want to so I may use it directly with my xbox 360, since it won't pick it up on my pc list.
Comment: Did you get a solution for this?
Answer: I had the same issue with my 4TB WD My Book external drive and I did the following:

Download and install WD Security from http://support.wdc.com/downloads.aspx?DL
Plug your external hard hard drive to your computer and unlock it with the password
Run the WD Security application
Select the "Remove password" and type in your password and then click on the button that says Update Security Settings as shown in the picture below:
Answer: Your question is not clear, has the password been set, and you forgot it?
http://community.wdc.com/t5/External-Drives-for-Mac/WD-My-Book-1TB-locked-out/td-p/6860 states the following:

Unplug and plug in Drive again.
You will be prompted to type in password.
Type five wrong password.
After 5th time, you will be prompted with screen to check off and
  give your drive storage back in
  exchange of giving up data.  * There
  is no way to get password back (no
  exception; not even from WD)*

Or look for the user guide here
http://support.wdc.com/product/download.asp?level1=1&lang=en
Answer: This came to the front page, so I'll reply, but the OP probably wiped it already.
See if you had installed anything from a CD originally to enable this password set-up. You should summon the same program to seek the option to change the known password to an empty one. If you don't remember the original password, then you will have to clean-wipe it.
My best guess is that the PC list means your "My Computer" list of disks. If it used to just be there originally and suddenly disappeared, you have a disk problem totally unrelated to passwords. Then I would recommend running the original CD's recovery programs (or use the Moab's links and download anything that looks useful for your exact WD model.)
Answer: You can remove password permanently using WD Discovery utility as follows.

Download WD Discovery according to your OS
Install the utility on the PC or Server
Open WD Discovery from system tray icon
Go to Storage tab
Unlock the Drive from drive list
Go to the option right clicking on the wheel icon on the drive
Click Remove password

Note: Never remove the drive while unlocking the drive.


Adding multiple folders with Add-PnPFolder appears impossible in a Runbook

Question: I have some simple code to add a couple of folders to a SharePoint Site library. Locally it runs smoothly in seconds, but in a runbook the same code runs increasingly slower, resulting in getting the runbook suspended. Looking at the error messages, it seems that somehow it even goes into a loop of repeating commands. Max. 3 folders are created. In Azure and local I have the same module ( PnP.Powershell 1.2.0)
Any tips are very welcome.
<code>$dcSharePointRootUrl = "https://XXXX.sharepoint.com/sites/"
$SiteUrl = "13Test"
$credential = Get-AutomationPSCredential -Name "XXX" ;
$targetSite = $dcSharePointRootUrl + $SiteUrl
Connect-PnPOnline -Url  $targetSite -Credentials $credential
$targetFolder =  "/sites/"+ $SiteUrl + "/Shared Documents"
Add-PnPFolder -Name "Technical proposal" -Folder $targetFolder
Add-PnPFolder -Name "Procurement" -Folder $targetFolder
Add-PnPFolder -Name "Engineering" -Folder $targetFolder
Add-PnPFolder -Name "Commercial proposal" -Folder $targetFolder
</code>

Error messages: Add-PnPFolder : A file or folder with the name
https://xxxx.sharepoint.com/sites/13Test/Shared Documents/Technical
proposal already exists. At line:16 char:1 + Add-PnPFolder -Name
"Technical proposal" -Folder $targetFolder +
<code>CategoryInfo : WriteError: (:) [Add-PnPFolder], ServerException +
FullyQualifiedErrorId :
EXCEPTION,PnP.PowerShell.Commands.Files.AddFolder
</code>
Answer: a runbook needs a var, like :
$dummy = Add-PnPFolder -Name "Technical proposal" -Folder $targetFolder


What are the Primary colors? RGB or CMY?

Question: Our printer in office uses three Imaging units of Magenta, Cyan and Yellow.
I thought the primary colours were Red, Green and Blue?
Comment: @Tetsujin, I don't know, the order of the ink cartridges in my printer is MCY.  Are you sure you don't get different colors if you list the letters in a different order?  :-)
Comment: @fixer1234 - only if you put the inks in the wrong slots ;) CMYK is just 'what it's called' Even on an offset press you don't always print them in that order [you do for newspaper, but not most other processes]. This gives a more-than-detailed explanation as to the whys & wherefores - http://the-print-guide.blogspot.co.uk/2009/07/ink-sequence-4c-process-beyond.html [I used to be an offset litho operator, but this article knows more than I do, tbh]
Answer: They both are, in a way. RGB (Red, Green, Blue) and CMYK (Cyan, Yellow, Magenta, Black) are both common color spaces. Generally, RGB is used for additive color mixing (hint: Light-mixing, or LCDs, LEDs, stage lights, etc.)

while CMYK is subtractive (colors on a page which absorb light, i.e. most printed documents).

You can't translate every color between color spaces - there are some shades which can only be accurately represented with certain pigments. Further, some colors can be difficult to match between color spaces. Here's a simulated example of how a color will appear on your screen (RGB) vs how it will come out on a sheet of paper from a typical inkjet printer (CYMK):

It's because of this that many professional artists and design studios have to use high-quality IPS monitor panels which can reproduce a much larger gamut of colors than the standard RGB, and further make sure that they are perfectly tuned so that the colors that show up on the monitor are exactly the same as what comes out of the printers that their artwork will be printed upon.
This article lists some common color spaces and their uses.
Comment: See also: http://en.wikipedia.org/wiki/RGB_color_model
Comment: @mr5 That's actually a very muddy purplish brown (You can see black in the RGB example above). This is why black is added as a 4th pigment to this color space - it's the only way to get true black :)
Comment: I have to say this is very useful answer plus references!!1
Comment: +1 for learning something new, mainly "CMYK is subtractive"
Comment: I thought you can't produce black using CMY combination?
Comment: @mr5 CMY*K* - the K stands for "key", or black.
Comment: @DarthAndroid yeah but in your illustration, overlapping CMY colors somehow produced the color black
Answer: As Darth Android deftly explained, they both are. There are more than one set of primary colors. In fact, there are infinitely many. If you plot the colors RGB or CMY on a color wheel and rotate all 3 points the same arbitrary number of degrees, you get a new set of primary colors. These particular sets are simply the most popular. There are 3 different hues of primaries (a primary triad) in both CMYK and RGB due to human beings being primarily trichromatic: we have 3 different types of cone cells (though we also have rod cells, but they generally contribute very little to color vision). But aside from that, the choice of primary colors we use is largely arbitrary—for the most part determined by tradition and practicality. RGB was developed first, and CMY was developed as a subtractive compliment to the RGB additive primaries:
Green + Blue = Cyan
Blue + Red = Magenta
Red + Green = Yellow

or from a subtractive standpoint:
Given that:
White light = Red + Green + Blue

Then:
White - Red = Green + Blue = Cyan
White - Green = Blue + Red = Magenta
White - Blue = Red + Green = Yellow

Therefore, you can think of CMY as -Red, -Green & -Blue.
The science and psychology of color and color perception are fascinating fields, especially when comparing the difference between perceived colorspaces and scientifically constructed color models. Before the inception of modern scientific color theory, the most common primary colors were RYB and VOG. And even today RYB is considered the 3 psychological primaries, or RYBG the 4 psychological primaries, even though they are not equidistant apart on perceptually-uniform colorwheels. And even the scientifically constructed RGB/CMYK color models don't have any bearing on the objective nature of colors beyond human color perception, in that, if a person were to be born with an extra type of cone receptors, then through their tetrachromatic color perception, the images produced by an RGB television set would bear little resemblance to the natural colors of objects.
Comment: To amend slightly - RGB and CMY are the most popular because they give the widest gamut of achievable colors within the range that's most important to human vision. And then that was modified per what was achievable. RGB in a CRT color TV were not quite the same colors as we see now on an LCD - the phosphors in color TV tubes were picked as a compromise for brightness. Red was a problem for a long time...


Generational ship loses power/gravity in space, and inhabitants forget purpose of mission

Question: I read this story maybe 15-20 years ago. It was about a massive spaceship on a voyage that would take many generations to reach their destination. Somehow the ship breaks down, losing power and gravity, and over years the people on board revert to a primitive society, using fire for light and "flying" down long dark corridors... I remember a boy who (I think) had to flee into the "forbidden" part of the ship... the story ends with him somehow powering up the broken ship, lights and gravity kick in after centuries, all the people fall to the "ground", and the ship begins to head toward it's now mystery-destination.
Answer: The part about the ship powering up and gravity kicking in doesn't fit (as far as I recall), but the rest of the description sounds a lot like Heinlein's classic "Orphans of the Sky" (originally published in 2 parts "Universe" and "Common Sense.")
Comment: Orphans of the sky was the first one that came to my mind as well. Great example of a technocracy, where the ones that still held the "key" to the power/control functions were the ruling class of an otherwise degenerated society.
Answer: I remember a similar question:
Book about an isolated space ship where a new society/religion develops after order collapsed
As you can see, there are several books resembling the described scenario:

Orphans of the Sky by Heinlein (protagonist here is a young man)
Non-Stop by Brian Aldis (the main character is a mid-aged man)
Earthseed by Pamela Sargent (haven't read this)
Mayflies by Kevin O'Donnell Jr (haven't read as well, but according to answer the protagonist is a scientist)

There are some other books mentioned as well.
Answer: This sounds a lot like Harlan Ellison's ill fated screenplay "The Starlost"
Unfortunately, the producer's strayed from his vision and Ellison divorced himself from the TV show.
The original screenplay was adapted into a novel by Edward Bryant in 1975 called "Phoenix without Ashes".
Here's a link to the novelization.
And here's a link to the Starlost TV show only 16 episodes were made.
Answer: It sounds a little bit like Raumschiff der Verdammten (german title) from Kurt Mahr.
I don't know the english title.
The Glorious (the ship) breaks down because of Sabotage (pilot and copilot are from different companies and are trying ti kill each other and the copilot sabotages the drive) and in the end it is rescued from ships from earth, because the FTL travel is invented sometime after the start of the Glorious.
A german review can be found here: http://schundliteratur.blogspot.de/2012/05/kurt-mahr-raumschiff-der-verdammten.html
Answer: Sounds close to "Journey to Alfahsfere" by Mike Combs.  Looks like he published it online in 1996. Only in Alfasfere, there is no gravity loss, and

 only the BetaSphere inhabitants go primitive, AlphaSphere retains their technological knowledge and knows of the continuing mission.
Answer: Both of these books bear resemblance to the story you are describing:

Ring - Steven Baxter
Mothership - John Brosnon

They both have ships where there are break downs and primitive society forms. In both there are young males who explore parts of the ship that is outside of their 'world'. There is definitely a gravity problem at some point in Ring although I cant remember if there is one in mothership and not sure it is that old.
Comment: OH NO! I have mixed my plot lines up. Sorry. I read Tau Zero and Ring - by Steven Baxter at some point last year and I have somehow melded the stories together. I Think it is perhaps me that needs to re-read!
Comment: On the plus side, the two story lines together make a fantastic one in my head.


How does the disqualification of Alexei Navalny affect the legitimacy of the Russian presidential elections?

Question: Now that Alexei Navalny has been barred from the elections Vladimir Putin will be the only candidate in the Russian elections to be held next year. Is it illegal to bar a candidate even though he is eligible? This might set a precedent where powerful rulers might bar other candidates from taking part in the elections.
Comment: Not entirely sure what the question is here? People can be legally barred from elections for a variety of reasons, that shouldn't be surprising and of course, it's not unique to Russia.
Comment: If no one actually considers the results to be a "legitimate" democratic exercise to start with, does a further demonstration of that make it less legitimate than before?
Comment: "legitimacy" seems like a rather squishy and subjective concept absent a formal definition. So "yes"/"no" answer seems impossible for the first question (and a trivially googleable "yes" to the second one).
Comment: "Vladimir Putin will be the only candidate"  Citation needed.  Note that the existing citation explicitly says, "other critical politicians permitted on to the presidential ballot".
Comment: If you know you can't win the election, just break the electoral laws and then when you get barred from running, you go crying about it on western media, who will be happy to report on it. They will then give you titles as a "leading opposition figure", even though you have less than 10% support.
Answer: Navalny has been barred from standing in the election due to a conviction on corruption charges, and because of his outstanding criminal record by Russian law this means he cannot run for president.
After his first trial for these corruption charges the European Court of Human Rights ruled that his trial was unfair and demanded a retrial, following which the ruling was overturned, sent back to a lower court, and that lower court affirmed the corruption charges.
In this sense from an internal legal standpoint the elections are legitimate, but the real question at hand is whether the trials themselves were fair or whether Putin and/or his administration are manipulating the courts to keep what most view as the only legitimate challenge to Putin's rule out of the election. As with the assassination of Boris Nemtsov, it reeks of foul play but it is challenging to prove anything.


What starting AC and HP does a quadruped eidolon have?

Question: I'm new to Pathfinder and am trying to create a quadruped eidolon for my summoner. How do I determine its armor class and hit points?
Answer: Both the eidolon of the traditional summoner and the eidolon of the unchained summoner start with 1d10 hp from its 1 outsider Hit Die (and see this question) but no initial bonus to their Armor Classes beyond what their ability scores and base forms provide (a quadruped base form of either eidolon type gains a +2 natural bonus to Armor Class, for instance). Either eidolon's number of Hit Dice, bonus to Armor Class (which can be split as the summoner picks between an armor bonus and a natural bonus), and other special abilities increase as the traditional or unchained summoner advances in levels.


Show related product in cart page Magento 2

Question: I want to show related product in cart page, each product at least will have 3 or more related product, is there a way to do this?
Answer: I think you're looking for Cross-sells. According to official document,

Cross-sell items are similar to impulse purchases positioned next to the cash register in the checkout line. Products offered as a cross-sell appear on the shopping cart page

You can add cross-sells following the link provided
Answer: add in Cross-Sells items its a default option


EVM bytecode instrumentation

Question: How can I instrument the EVM bytecode for runtime monitoring?
Is there any technique or implementation for that?
Comment: we aren't using these words like "instrumentation" here, please translate what you mean by that
Comment: also define: `monitoring`
Comment: I want to do concolic testing for EVM bytecode. According to what I understand about a concolic testing, we have to instrument the code before analyzing it. So,  I use the word instrumentation. And for monitoring I meant concolic testing based on the instrumented code and monitor for existing vulnerabilities. I would be glad to correct me If I am wrong about this concept .@Nulik
Comment: I have been working with assembly language for years, and this is the first time I hear about conocolic testing or instrumentation. I can say for sure that nobody does this. So you better write a specific request on what do you want to do.
Comment: tell your teacher that theory is different from practice
Answer: I think what you're looking for is something that will create an intermediate representation (IR) between Solidity and EVM bytecode, and which will act as a high-level assembly equivalent which you can instrument, rather than instrumenting the EVM bytecode itself. (There are a few common tools for doing this in the wider world, such as LLVM which is used in C instrumentation.)
I'm not sure what is commonly used in the Ethereum ecosystem, but there are several papers detailing techniques. See, for example: SIF: A Framework for Solidity Contract Instrumentation and Analysis
Edit:
Actually it looks like a tool called Zeus will now create LLVM bitcode from Solidity, so that might be a place to start.
Comment: That is really helpful and similar to the work done in C. But, what if I want to instrument the bytecode itself, something like binary or bytecode instrumentation in C? Is there any tool for that? @Richard Horrocks
Comment: @richard Horrocks, please explain what you mean by "you can instrument, rather than instrumenting the EVM bytecode itself". I don't know what is instrument and what is instrumentation. Please define these words without using them in the defnition. This paper "ContractFuzzer: Fuzzing Smart Contracts for Vulnerability Detection" uses the "instrument" and "instrumentation" terms witout defining them.

EVM bytecode instrumentation