Can I say "We sell sea food by the weight of the item?" in a restaurant?

Question: In my restaurant, we sell seafood this way: if you choose a big fish and it weighs 1.5 kilograms, you only have to pay for 1.5 kilo of that fish and  don't have to buy more or less. I mean you don't have to do that to round up or round down the weight of the item, you don't have to buy exactly 1 kilo or 2 kilos. So in this case, can I say "We sell seafood by the weight of the item?"
Comment: You probably will get better answers from Americans, I know shellfish restaurants are big in the States, and the protocol you described is not uncommon. It's very likely that there's a typical catchphrase, which restaurants use, I don't know what it might be.
Comment: It is unclear what precisely is being asked here. If one sells something by weight, *of course*, one may, and should, say that one sells it by weight. What is the reason for doubting it?
Comment: I imagine that the fish is weighed in front of the customer? Is that so? Are we talking about lobsters, crabs, for instance? Or does it include also non-shellfish, e.g. octopus (something I would expect to *see* it in a seafood menu)
Comment: @ Mari-Lou A, yes the fish is weighted in front of the customer and we're talking about creatures that weigh over 1 kilo, so that include some big non-shellfish as well.
Comment: If I were to see a sign that says "we sell seafood by the weight" in a *restaurant*, I would understand. I don't think adding "of the item" is necessary, it's implied in the claim.
Comment: @Mari-LouA thank you Mari, your answer cleared my doubt.
Answer: It's idiomatic to say that you sell the seafood by weight.

by weight
  as determined by weighing
  - Collins

Here are a couple of examples from the web:

Selling Products by Weight or Length
- Nextar
If you are buying or selling seafood by weight, you need to know about Australia's trade measurement laws.
- National Measurement Institute, Trade Measurement and the Sale of Seafood
Answer:
Can I say "We sell seafood by the weight of the item?"

It seems reasonable, you don't want to cut an estimated bit off and add a bit back to make some exact weight, you want to sell one whole item, whatever it weighs, for however much per kilogram.
If you were selling eggs you only want to sell whole eggs, not non-integer quantities.
What you need to be careful with is standard industry practice and the law in your area.
Sometimes terms like "individually measured" are used, other times it's "catch-weight".


In India, what is the best time to view the geminid meteor shower in 2013

Question: As of the time of writing this question, the meteors should have appeared, but so far I haven't seen any. What time would be the best to view them?
Answer: They should be visible any time at night (note that longitude has little to do with observing meteors), but there are many things that could thwart your observing.

Bright lights: In a big city you will see far fewer meteors. In a big enough city, you won't see any. On that note, if you keep checking a mobile device with a backlit screen, you probably won't see anything.
The Moon: The Moon will unfortunately be up until something like 4 AM local time (assuming I plugged numbers in correctly to the US Naval Observatory's table). Just as with cities, this will cover up smaller meteors. Just try not to stare directly at the Moon lest you lose night vision entirely.
Limited view of the sky: The key to watching meteors is to see a large amount of the sky at once. Never use binoculars or a telescope. The idea is to get comfortable by laying down (yes, this is important - people who crane their necks get tired after 20 seconds and then stop looking up!) and just look at as much sky as possible. Your eyes naturally catch and follow movement, so you'll instantly focus on a meteor once it comes into view.

As for where to look, the answer is "everywhere." Meteor showers are named after the radiant - the point in the sky from which the trails seem to originate if you trace them backward far enough. This shower originates in the constellation Gemini, which isn't terribly recognizable, but can be found by locating Orion:

Move from his belt to his right arm (the one indicated by the very red star Betelgeuse) and keep going until you come across two reasonably bright stars. That is Gemini. It is important to keep in mind, though, that meteors streak across other parts of the sky. Just because they seem to originate from Gemini doesn't mean they're actually visible there. Knowing the radiant just helps with knowing what direction to expect the streak to be going.


How to downgrade Samsung Galaxy Mini S5570 from 2.3.6 to 2.2.2?

Question: I need help with downgrading my Samsung Galaxy Mini (S5570) from 2.3.6 to 2.2.2.
Answer: You can search and download "Samsung S5770 Android 2.2.2 firmware" in google or forum.xda-developer.com in Samsung S5770 section, you can get official ROM and Custom ROM there, then flash it via ODIN (if official) or via custom recovery if Custom ROM
Comment: It looks like the OP isn't well versed in Android's tools. It would help if you could expand your answer with links to the ROMs, and instructions for flashing them.


Add Sublime Text 2 to the right click context menu in Ubuntu 12.04

Question: Title pretty much sums my question. I want to open a folder in sublime text by right clicking the folder and clicking on "open folder in sublime text" context menu. I am using Ubuntu 12.04
Comment: For Ubuntu 21.04 and similar - https://github.com/atutorme/subl-nautilus. Uses the python3-nautilus package to add a context menu entry. Adapted from `code-nautilus`.
Answer: Assuming you followed guide on:
http://www.technoreply.com/how-to-install-sublime-text-2-on-ubuntu-12-04-unity/
You simply need to add a %f to your Exec line in sublime.desktop like:
Exec=sublime %f

Comment: %f or %F didn't work for me, I still don't get the program listed
Comment: Works fine; I edited my launcher (right click on desktop icon > properties > launcher, add %f at the end of the 'command' line) and all of a sudden it's in my context/right click menu
Comment: your link doesn't work. This is why you should add more info instead of just pasting links in SO answers.
Answer: This is what I have managed to get Right click context menu for Sublime Text 3:
Using Nautilus-Actions Configuration Tool, either installed through Ubuntu software center with this link or through ubuntuupdates.org
This will allow you to create right click context menus and actions to your liking.
I have created such an extension:
Nautilus-Actions_XML_Schema
OR
Nautilus-Actions_Schema
For further information check out: blog.ndroidians.com
Answer: Right click -> open with other application -> show all applications -> open with sublime text
Comment: sublime text 2 is not there in the list of applications
Comment: It doesn't appear when you select the  "show all applications" ?
Comment: Hrishi, yeah that works however it'd be nice to have it on the first level of the menu like the Open menu command
Comment: I choose `Open With` -> `Other Application` -> `Show other applications` (there is no "Show _all_ applications"), and Sublime Edit is not there. I'm quite sure I installed it manually, ie not with apt-get. Perhaps it must be installed with apt-get to appear in the list?
Answer: This guide worked form me on Ubuntu and Mint. http://www.technoreply.com/how-to-install-sublime-text-2-on-ubuntu-12-04-unity/
Answer: Make sure that you have copied the sublime .desktop file into the /usr/share/applications/ directory. That should work resolve this issue.
Answer: To open a folder in sublime from nemo by right clicking in the pane for that directory, go into the folder "usr/share/nemo/actions" as sudo and create the file "subl.nemo_action" and put the following contents into it:
[Nemo Action]
Name=Open folder in Sublime Text
Comment=Open current folder in Sublime Text
Icon-Name=subl
Selection=any
Extensions=any
EscapeSpaces=true
Exec=/bin/sh -c "cd %P && subl ."
Dependencies=subl;

I found this solution HERE, but had to change "subl3" to "subl" for my case, and had to find where to locate the file.


Azure AKS virtual node and daemon set

Question: We are currently running AKS k8s cluster. this cluster is using a virtual node which is to handle bursting load when request/second reaches a specific limit.
we are also trying to explore APM tools like new-relic.new relic provide integration with k8s by daemon set.
query
as per my understanding daemon set run on each node.
what will be the case for virtual node and daemon set?
will daemon set run 24 by 7 on the virtual node, if yes then how to reduce cost and monitor pods running on a virtual node?
Answer: DaemonSets are currently not supported via AKS virtual node (as per documentation)

Azure AKS virtual node and daemon set


Chrome Angry Birds engine?

Question: Was Chrome AngryBirds game made using html5 canvas? And if yes: what kind of engine did they use?
Comment: I'm voting to close this question as off-topic because we do not support questions asking "how was this game made" or "how did this game do that". Such questions are mostly speculative, and not constructive; we usually edit the question to ask "how can ***I*** do this feature, but this question is too old for such edits to be constructive.
Answer: Yes. ForPlay.
WebGL and Canvas 2D code paths exist for maximum performance and platform support respectively. The ForPlay GWT library helps with the abstraction. See the Google IO presentation Kick-Ass Game Programming with Google Web Toolkit for details.
Comment: I just watched the presentation and I think I would like to try out ForPlay in a later project. Seems like a really nice approach. Thanks for the link anyway!
Comment: AFAIK ForPlay aka PlayN does not let you write in "HTML5" ... the sourcebase is in Java, and it compiles into other formats. Read: You're not actually writing in HTML5; machine translates your Java to HTML5..
Answer: It is based on WebGL (which means canvas is used, but not the standard canvas environment).
As iOS uses OpenGL I think they ported that to javascript.
Comment: I made some test http://html5test.com/ and it said that I have no WebGL context;)
Comment: And my WebGL debugger popped up so it can also use WebGL, so uh, what Vincent said.
Answer: Inspecting the page element gives me <canvas width="1024" height="768"></canvas> so I guess that means it is canvas.
As for the engine, I assume they ported their iOS one.

Chrome Angry Birds engine?


TS or TRS cable from mixer to speaker?

Question: I am running a Behringer XR18 to a Bose L1. I use the Left aux output (xlr) on the Behringer to the guitar line in to the Bose (1/4"). I currently run the female xlr to a TS. Should i use a TRS instead? Or will that bring unwanted noise or be unbalanced?
Comment: Did you check the manual before asking?
Comment: The Bose accepts both TRS and TS...
Comment: The manual doesn't say it does. Page 2. I checked.
Comment: I just didn't know how this would affect output/ balance
Answer: You may use either a TS or TRS to the line/guitar input of the Bose either way. The input is probably TS since it is set up to accept an instrument level or Line level and nothing indicates that it is balanced input.
If you send a balanced signal through a TRS jack to a TS input, the second signal will be sent to ground and not used.
If the Bose does accept balanced signal through TRS, then you can send a longer run with less noise by using a TRS, but otherwise your current configuration should work fine.

TS or TRS cable from mixer to speaker?


problem with upgrade to 16.04 from 14.04

Question: I upgraded Ubuntu 14.04 to 16.04, but I had some problems with installation, so I wondered if I could install 16.04 again without using USB memory stick or DVD? Or if I can return to 14.04
Comment: "so I wondered if I could instal 16.04 lts"again
Comment: probably this is not possible cause it is not windows , well you could a reinstall the ubuntu from usb stick without losing your files and dont know about 16.04 , but in 14.04 you could create a bootable usb of the the os without any iso from the startup disk creator.
Comment: Why can't you use the USB stick or DVD again?
Answer: Maybe try this solution: https://ubuntuforums.org/showthread.php?t=2318779&p=13466943#post13466943
If you can login in the terminal, then you are able to do this simple procedure. Essential should be the line sudo dpkg --configure -a (if you run as root, you don't need the sudo) and you can gracefully poweroff after that using sudo poweroff. It helped a some other people, like here Error after upgrading from 14.04 to 16.04


Is there a service for recurring buying of Monero every 2 weeks?

Question: I know Coinbase has the ability to buy BTC, LTC, and ETH on a recurring set time. But is there a service that can do this for Monero? I don't care what the price is, but I just want to buy monero every week as a way to dollar cost average.
Answer: There are two possibilities:

You find an exchange where you can set up buying an order every week. Not really sure but i think that at Kraken this could work.
You create an account on an exchange, get API keys from them and execute the API call to create a buy order every week. If you really want to automate this, you could set up a python script (or any other programming language) on Heroku (which you don't have to pay) and let that execute periodically.


Moving bitcoins around

Question: I am doing some reading about bitcoin and my understanding is that miners get 25 BTC for every transaction that is made. This means that even for a transaction of 0.01 BTC 25 will be generated. Doesn't this mean that people will be able to create a lot of low valued transactions (constantly moving btc around) to generate more and more bitcoins?
Comment: No, you're confusing *block reward* (currently 12.5 BTC) with *transaction fees* (which are much smaller).
Comment: Ok blocks store transaction data right? so the number of transactions still affect the blocks. So doesn't that mean still that more transactions = more blocks?
Comment: Sounds like you've got some more reading to do. Blocks are found every 10 minutes *on average*. A typical block today might contain 2500 transactions or so.
Answer: The miner gets a reward of 12.5 bitcoins plus transaction fees every block, not every transaction.  Blocks occur approximately every 10 minutes, and the reward is cut in half approximately every 4 years.

Moving bitcoins around


How to view contract source code from ABI, address and bytecode?

Question: I have the address and ABI of a contract. I can also view the bytecode from that address on Etherscan but not the source code. Is it possible to get the contract source code using these information?
Answer: In general - no. Only bytecode is stored on the blockchain so you won't get it unless the author made it available by other means.
Etherscan's source verification is one way for the author to do that. You could also check the Sourcify contract repository to see if the contract metadata was uploaded there.
Other than that, if the project is open-source, you'll likely find the source repository on github or gitlab. In that case, however, you'll need to verify it manually to be sure it matches the bytecode deployed at that address - you can do that by compiling it locally and diffing the resulting bytecode.
Answer: You can decompile the code using a tool, but the output will not be what the input was, and is usually pretty far off. I believe etherscan has a tool to do this for contracts that are not verified. However, this can still give you some idea of what is going on inside the contract.
In terms of getting the exact source code, no. Unless the author makes it public somewhere, you will not be able to see it.


Why do directors make cameo appearances in their movies?

Question: This is something very common, that we all have been seeing since as long as we can remember. This question stemmed from my recent re-watching of Django Unchained, where Quentin Tarantino makes a cameo appearnce. I have always been intrigued by this. M Night Shyamalan, Peter Jackson, John Carpenter, Robert Rodriguez, Eli Roth, and many more, have made frequent cameo appearnces in their movies. The trend goes as back as Alferd Hitchcock's movies. I want to know more about this. What are the factros behind this gesture ?
Comment: While I'm not sure about all your examples, at least Mel Brooks and Quentin Tarantino often just play regular roles in their movies. I wouldn't call those cameos given their significance in most stories.
Comment: Right ! I have edited the question.
Comment: Dont' forget Stephen King as ATM Guy in his one coke-fueled Directorial outing: Maximum Overdrive!
Answer: There's no overarching right answer to this. I think there are a few reasons for it:
For starters, it's fun. You've mentioned lots of directors in your question who have done it and it's likely they all got a pretty good kick out of it. Think Hitchcock's many roles or Tarantino in Reservoir Dogs, or Pulp Fiction.
There's also a tradition argument. Stan Lee, for example, has done it for so long now that it's expected and many fans get enjoyment out of spotting him in each of his roles. The same applies to Hitchcock.
After the fun and tradition reasons, it's certainly plausible to suggest because they can. Many directors don't have the fame or recognition for a cameo role to be significant. But if someone like Tarantino, Scorcese or Peter Jackson does it, it's instantly recognisable given their fame. This can be compared to other, less famous, directors who wouldn't be recognised. Therefore, it certainly carries that making cameos gives them airtime and keeps them recognisable in the public eye.
These are just a few of the reasons. I'm sure other arguments could be made, such as the fact it saves money (such as in the case of a longer role, e.g. Tarantino in Django), but it seems to be mostly about a mixture of fun and tradition.
Comment: And I guess also the factor of giving your work a personal signature.
Comment: I don't think Tarantino needs to save any money...


raspicam c++ library

Question: can you give me a tutorial like video or anything about how to use raspicam library...?
i follow this url
https://www.uco.es/investiga/grupos/ava/node/40
but still don't get it
Answer: You have illegal characters on line 10 or the end of line 9. These most likely came from copying and pasting. The easiest way to correct the problem is to retype (do not copy and paste, and don't use and keyboard macros like shift-space) line 10 and line 9 if required.
More info on the causes and possible solutions can be found here and here.
As for tutorials certainly your Google foo is as good as anyone elses here. You may also want to look at the Python code which may be clearer.

raspicam c++ library


Changing the Order of Integration, Integrability

Question: Suppose I have the integral $\int_{0}^{1} \int_{y}^{1} x^{-3/2} \cos(\frac{\pi y}{2x}) dx dy$. I know that if I change the order of integration I get $\frac{4}{\pi}$. But how do I apply Fubini's theorem to do so (or can I?). I know if $\left| \int_{y}^{1} f(x,y) dy \right| < \infty$, then I can change the order, but I am not sure how to proceed.
Answer: Put the absolute value to the integrand, and you just need to check that
\begin{align*}
\int_{0}^{1}\int_{y}^{1}x^{-3/2}dxdy<\infty.
\end{align*}
Answer: Well we know that for your $f(x,y)$, $ |\int_{0}^{1} \int_{y}^{1} f(x,y) dx dy| \leq  \int_{0}^{1} \int_{y}^{1} |f(x,y)| dx dy  \leq \int_{0}^{1} \int_{0}^{1} |f(x,y)| dx dy $. If this is integrable, then you are golden.
Answer: Note that $|\cos{(...)}| \leq 1$
Also so you have $|f(x,y)|=|\cos{(...)}\frac{1}{x^{\frac{3}{2}}}1_{(y,1]}(x)| \leq  \frac{1}{x^{\frac{3}{2}}}1_{(y,1]}(x)$
Now $\int_0^1 \int_0^1|f(x,y)|dxdy=C\int_0^1 1-\frac{1}{\sqrt{y}}dy<+\infty$


I am confused in work-energy theorem, Why the ball doesn't go to the same height from which it fall down? (sorry if my grammer isn't correct)

Question:
Here's the figure, ball fall from height of 2 m (at point A)
But reaches the height of 1m at point P
Comment: 1. Please do not just put a question into the title, but also write an actual question in the body of the question. 2. Please add enough context to your question so that answerers can understand what the problem is: Where is that picture from? What is it supposed to depict? Is there friction involved? What are the points $A$ and $C$? What is this supposed to have to do with the work-energy theorem?
Answer: The key is to note that point C is a ramp, not a hill. The trajectory of the ball as it leaves the ramp is dependent very much on the angle of the ramp - a shallow ramp will result in a low, long trajectory, while a steep ramp will result in a high, short trajectory. It should be no surprise that the height of the ball depends on the angle you launch it.
The ball has sufficient energy to roll down a hill and then back up a hill of the same height, stopping at the top with zero kinetic energy. But that's not what happens here, the ball never stops. Since the ball always has some kinetic energy, it can't attain the same height, as that would require an increase in the total energy.
Comment: Why does it not go as a projectile till kinetic energy becomes zero and fall freely later on ? How is it constrained to follow that fixed path without energy loss.
Comment: @Aurelius The ball has horizontal velocity and no way to get rid of it when in freefall. When the ball is on the track, it can slow down horizontally as well as vertically, since the normal force from the track has a horizontal component. Without the track, only gravity acts on the ball, which only has a vertical component. Had the ramp launched the ball straight up, it would return to height A since none of the kinetic energy would be "used up" in the horizontal component of the ball's motion.
Answer: I'm not sure what your question has to do with the work energy theorem, but the ball doesn't reach the same height as its original height because it is still in motion (has kinetic energy) at the 1 m height.
For conservation of mechanical energy its kinetic energy plus gravitational potential energy at the 1 m height equals its gravitational potential energy at the initial 2 m height. Just before impacting the ground, when its height is 0 m, its kinetic energy will equal its initial gravitational potential energy.
Hope this helps.
Answer: Assuming no dissipation (friction, air drag), energy theorem tells you that the total mechanical energy is constant.
At the initial condition, the mechanical energy is completely gravitational potential energy
\begin{equation}
E_1 = m g h_1
\end{equation}
on the upper point of the trajectory there is the non-zero (if the trajectory is not vertical) contribution of kinetic energy as well
\begin{equation}
E_2 = m g h_2 + \dfrac{1}{2} m v^2
\end{equation}
so that
$h_2 = h_1 - \dfrac{v^2}{2 g}$.
As an example, if the section OC was horizontal and the ball kept going on horizontal surface, it would have zero height w.r.t. that plane keeping constant horizontal velocity $v = \sqrt{2gh}$.
Answer: Your ball would accelerate on its way down and have a velocity:
$ v1=v0+gt$ (that is g right? If no air drag is assumed, it should be. $v0,t$ respectively being the initial velocity and the time it takes to reach the bottom) at the bottom. And then change direction due to a collision with that surface and keep moving up till its velocity vector changes direction again due to the deceleration it experiences as a result of gravity. But the velocity it has at that peak would still be greater than $v0$ and so (as previous posters pointed out) it cannot have as high a potential energy as it initially did since its kinetic energy is higher than it initially was.
If no friction existed, $mgh+0.5m*v*v = constant$
Answer: Hey here in this question considering no dissipative forces present(friction, buoyancy,air resistance etc...)
On applying conservation of mechanical energy...
We get, mgh=mgh'+1/2mv²
See here I have added 1/2mv² as well, as the particle is in projectile motion it is having a velocity parallel to ground which moves it forward so a kinetic energy is present even at its top-most point.
The particle is having a projectile motion( on considering a simple case on Earth of a ball having a velocity and leaving a ramp)...Since we get an extra term of 1/2mv² the final height h' is lesser than the initial height h.
Hope this helps you...


What is the tax treatment of scrip dividends in the UK?

Question: What is the tax treatment of a scrip dividend in the UK?  Do I declare the value of shares as income or the actual value of the dividend?
Answer: I wrote about this in another answer:

You can sell the scrip dividend in the market; the capital gain from this sale may fall below the annual tax-free allowance for capital gains, in which case you don't pay any capital gains tax on that amount. For a cash dividend, however, there isn't a minimum taxable amount, so you would owe dividend tax on the entire dividend (and may therefore pay more taxes on a cash dividend).

Since you haven't sold the shares in the market yet, you haven't earned any income on the shares. You don't owe taxes on the scrip until you sell the shares and earn capital gains on them. HMRC is very explicit about this, in CG33800:

It is quite common for a company, particularly a quoted company, to offer its shareholders the option of receiving additional shares instead of a cash dividend. The expression `stock or scrip dividend' is used to describe shares issued in such circumstances.
The basic position under tax law is that when a company makes a bonus issue of shares no distribution arises, and the bonus issue of shares is not income for tax purposes in the hands of the recipient.

Obviously, if this is an issue for you, talk to a tax professional to make sure you get it right.
Comment: The page you cite goes on to say that the law was changed so that income tax is charged.  More details in my answer.
Answer: Scrip dividends are liable to income tax in the same way that cash dividends are. After the tax free dividend allowance of £2,000 (fr 2018-19 onward) had been used then you pay tax at the appropriate self assessment rate.
If the value of the scrip dividend shares varies by more that 15% from the value of those share on the scrip dividend payment date, the the HMRC have the right to use the higher value for taxation purposes.E.G:
Cash equivalent value of scrip shares issued = £1,000
No. of shares issues                         = 100
cash equivalent per share                    = £10
So provided the stock market price per share was in the range £8.51 to £11.49 on the payment date, then you quote the cash equivalent in your tax form return i.e £1,000 for these shares
Answer: The HMRC website says:

Stock dividends are treated as income by virtue of CTA10/S1049, and taxable as savings income under Chapter 5 of Part 4 of ITTOIA05 (sections 409 to 414).

ITTOIA05 is the Income Tax (Trading and Other Income) Act 2005, and says:
409 Charge to tax on stock dividend income
(1) Income tax is charged on stock dividend income.
(2) In this Chapter "stock dividend income" means the income that is treated as arising under section 410.
411 Income charged
(1) Tax is charged under this Chapter on the amount of stock dividend income treated for income tax purposes as arising in the tax year.
(2) That amount is the cash equivalent of the share capital on the issue of which the stock dividend income arises (see section 412), grossed up by reference to the dividend ordinary rate for the tax year.
Answer: The HMRC website would explain it better to you. There is a lot of factors and conditions involved, so refer to the HMRC website for clarification. If your question had more details, it could have been easy to pinpoint the exact answer.

Do I declare the value of shares as income

Why would you do that ? You haven't generated income from that yet(sold it to make a profit/loss), so how can that be declared as income.


What are equivalents for Windows 7 Phone PhoneCallTask, EmailCompmoseTask, and BingMapsTask in Blackberry Cascades

Question: I am trying to find equivalents for Windows 7 Phone PhoneCallTask, EmailComposeTask, and BingMapsTasks in Blackberry Cascades Beta 3 SDK - I found one for the PhoneCallTask which is (bb::system::phone::Phone phone) - which has a function called requestDialpad, which is supposed to bring up a dialpad, but it does not do that (I am using Blackbery 10 Dev Alpha Simulator) - so I was wondering how to fix that or if there is a better class for phone calls.  Also for EmailComposeTask - I haven't managed to find anything for that.  For BingMapsTasks - I am using a WebView for displaying a Bing map at the location I want - but it doesn't show the map (it's just black) - maybe that's an issue with the simulator - but I was wondering if there was something better for that too.
Answer: To do this you will want to use the invocation framework in order to bring up cards. However the documentation on this has not yet been fully released. You will however, want to check out the MapView sample app.


Removing a WPF ListView's "classic" indented border

Question: How can I remove the "classic" indented border from around my WPF ListView control? Setting its BorderThickness to 0 does not get rid of it.
Answer: Don't know if its a former version of WPF, but on Visual studio 2008 the following is enough to remove all borders and colors of a listview control
<ListView Background="Transparent" BorderThickness="0">

Comment: Tested with Visual Studio 2013 targeting .Net 4.5
Answer: For a lot of the built-in WPF control styles, you need to override the ControlTemplate to get this level of control over the rendering.
Here is the MSDN page that provides the ListView ControlTemplate, with instructions on how to use it -- basically you are inserting local copies of all the styles for the ListView control, which then override the default control look and feel.
To get rid of the indented border, you will need to find the specific border definition in the control template that is causing the behavior you want to modify; there are several of them, but it should be easy enough to figure out which one is causing the indentation using trial and error and/or Snoop.
Comment: Already an old post, but finally this helped me: `Background="Transparent" BorderThickness="0" Padding="0"` Set it to every intended control that supports a border.
Answer: listview1.BorderStyle = BorderStyle.None

Comment: Maybe it is my fault, but I've found no such property in WPF for `ListView`.


Word for the fear of learning something new and forgetting something you know

Question: Is there a word for the (probably irrational) fear of learning something new and maybe forgetting something you already know?1
Comment: "Brain overflow" -- it's a constant hassle for me (and the fear is perfectly rational).
Comment: I should call it *the Holmes fallacy* after the passage in Chapter II of [Conan Doyle's  *A Study in Scarlet](http://www.gutenberg.org/files/244/244-h/244-h.htm)* in which Watson discovers Holmes to be ignorant of the Copernican or heliocentric theory of what we now call the solar system.
Comment: I know this happened in the BBC show with Benedict Cumberbatch, but this did really happen in the original literature?! That's crazy!
Answer: The word I suggest covers more territory than the narrow sense you mention. It doesn't touch directly on the sense of "and maybe forgetting something you already know", although that is a component of the fear commonly expressed by those who suffer from it. The word has been in use for 130 years, at least:

neophobia n.
  A tendency to dislike anything new; fear of novelty.

(Collins English Dictionary – Complete and Unabridged, 12th Edition 2014. S.v. "neophobia." Retrieved May 5 2016 from http://www.thefreedictionary.com/neophobia )
A very similar term, rarer in use than 'neophobia' but as longlived, is this borrowing from Italian:

mis·o·ne·ism n.
  Hatred or fear of change or innovation.

(American Heritage® Dictionary of the English Language, Fifth Edition. S.v. "misoneism." Retrieved May 5 2016 from http://www.thefreedictionary.com/misoneism )
For your narrower sense, but omitting "something new", which seems redundant when used to refer to things to be learned, a technical term from medicine works. As with the broader terms 'neophobia' and 'misoneism', the word for the specific phobia doesn't encompass the "and maybe forgetting something you already know" dimension:

sophophobia
  Morbid fear of learning.

(Segen's Medical Dictionary. S.v. "sophophobia." Retrieved May 5 2016 from http://medical-dictionary.thefreedictionary.com/sophophobia )


Why is the sun "Shemesh" in hebrew

Question: I understand the word Shemesh comes from Shamash which means to serve. According to Jewish philosophy, why is the sun called a servant? Why is it more of a servant than the moon, or the wind, or even grass?
Comment: This question isn't about language in the etymological sense; it's looking for a drush about the word - just like Chazal so often do for both Hebrew and Aramaic words (such as אלמנה - על שם מנה and in countless other places). The Shelah, Maharal, and so many more thinkers have given philosophical insights based on similar ideas, which have to do with theology, not etymology. (In short: I think this questions shouldn't be on hold. Maybe it can be reworded to say 'is there a lesson to be learned from...')
Comment: I asked this question under the assumption that there was a p'shat that had a good lesson to learn from it. It wasn't just a random "why is the sun called Shemesh" but rather "does anyone know a good vort on this topic because I vaguely remember such".
Comment: Thank you @Matt that was my intention exactly. You explained it perfectly
Answer: Zohar Chadash (Beraishis 518) states that the sun is so called because it 'serves' humanity and sustains all life - משמש את הכל. This is also quoted in the relatively obscure Midrash Tadshe, no. 20, and a similar reason is given by the Maharal (Chidushei Agados Nedarim 7b). I believe this theory better explains why the sun, as opposed to the stars or constellations, was given this name, as it literally does support all of life on earth more than any other astrological body.
The theory that it needs to be emphasized that it's one of God's servants because people were wont to serve the sun (see Rambam Hil. Avodah Zarah 1:1) is one that I've heard as well, but cannot find a source for it.
Comment: I've never heard my vort before. I thought it was my own chiddush lol
Comment: I think it's the Meshech Chochmah -- originally the sun was "the great illuminator", but Avraham Avinu coined the term "shemesh", from the Aramaic for servant, to highlight that the sun should not be worshiped, as it's just doing God's bidding.
Comment: @Tzvi after 3,000 years of Jewish history, chiddishim are very rare lol
Answer: I had a nice thought, but of course no mekor, since I thought of it:
The sun is one of the most powerful forces that humans know of. Perhaps God knew that one day people would worship other forces in the world other than Him chas veshalom. He knew that the sun would be a prime candidate for such worshipping, because of it's tremendous force and clear beneficence to this world. Therefore, He gave it a name that contains the root "servant" in it to show very clearly that the sun is only a servant of Hashem.
Comment: In Breishit, in the story of creation, the sun and moon are called "me'orot" - "things that make light". Then it states that G-d placed the sun and moon "limshol bayom uvalayla" - and there is a debate as to what the word "limshol" means. One of the translations means "to rule" and another means "to be an example" (not sure , an example for what?) If you accept the first exmaple, "ruling" like a king, a king "serves" his people. (at least that is the Judaic concept of what a Jewish king SHOULD do.)
Answer: A personal theory: When Abraham grew up in Ur, he became familiar with the Babylonian myths. He rejected most of them along with the idols that his father made. But he kept some of the stories and names that he grew up with.
Shamash was the Akkadian name of the sun god. In mythology, Shamash was the sun of the moon god Sin, and thus the sibling of the goddess Ishtar. In later Babylonian astral mythology, Sin, Shamash, and Ishtar formed a major triad of divinities, which still today plays an important role in astrological systems, though under different names: Moon, Sun and Venus.
Whether because Abraham brought the name with him from Ur, or because of the linguistic connections between Akkadian and semitic languages generally, Shemash and Shamash are basically the same word for the same thing, except in Judaism the sun is just the sun, not a deity.
Note: the following is speculative, but the linguistic connection is not. In Canaanite myths, Shemesh appears several times as El's messenger. This could be a clue about why he is considered a servant. Also in the Babylonian myths, Shamesh is the son while Sin [the Moon] is the Father, so Shamash naturally takes the subordinate role. In Israelite tradition the moon was more important than the sun in terms of both festivals and the calendar. Finally, on the menorah, the Shamash is a sun-like candle that serves the others with its flame. About the grass: in science, the sun serves the grass, not vice versa.

Why is the sun "Shemesh" in hebrew


iPad App orientation changes background flashes white

Question: I am working in InDesign DPS to create an iPad book and have options for both portrait and landscape views. Everything is working correctly except when I change the orientation of the iPad between portrait and landscape there is a white background that "flashes" briefly in the non-content area at the bottom of the screen until the destination orientation fills the screen.
How do I eliminate that irritant?
Thanks.
Answer: Isn't it your window ?
Change it's background color to black in your didFinishLaunch... : self.window.backgroundColor = [UIColor blackColor];
Comment: Hi Templar, that would work if I was working in Xcode, but I am doing this in InDesign DPS.


Pascal's law misunderstanding

Question:
I have a weird misunderstanding about liquid pressure.  On the diagram, I have two weightless and frictionless pistons on the two openings of the container. There is the same atmospheric pressure on both of them. So one piston has area A1 (the smaller one) and the other has the area A2 (the bigger one). Since the atmospheric pressure is equal for both the pistons and one has a bigger area than the other, the force on the larger piston would be greater than the smaller one. Then the larger piston should move down and the smaller piston should move up. But that doesn't happen. So where did I misunderstand?
Comment: Well, the force is greater, but it's spread out over a larger area.
Comment: Fluids only flow if there is a pressure difference.  The pressure on top of each piston is the same.
Comment: Do you mean that force felt by individual molecules on both the openings will be the same?
Answer: The upward pressure of the water on the bottom face of each piston is also atmospheric, so the net force on each piston is zero.  Therefore, each piston is in equilibrium, and it won't move.
Comment: Ok! wouldn't that be equal even with different levels ?
Comment: I don't quite follow.  Are you saying that you have different levels without having any external  loads on the pistons other than atmospheric pressure?
Comment: Yes. And I feel like due to greater force on the large piston , it should have gone downward and the smaller piston would go up.
Comment: If the columns aren't equal in height, then the system will not be in hydrostatic equilibrium, and the fluid in one column will be accelerating downward while the fluid in the other column will be accelerating upward.  Have you actually drawn a free body diagram on an arbitrary layer of fluid in each column showing the pressure forces acting above and below, the gravitational force on the layer, and, if they don't sum to zero, the mass times acceleration?
Comment: Yes, same thing would happen. I think there will be oscillation in the fluid column with that. The liquid level on both the opening remains same without  having any external loads on piston . But why is that ? Force on the two open faces are different but still the system is in equilibrium . Why does that happen ?
Comment: Your idea of oscillation is correct.  Like I said, why don't you do a force balance on the liquid layer (finite thickness) just below the surface to convince yourself that it can actually be in static equilibrium (with no tendency to move up or down).  This is, of course, due to the fact that the pressure is increasing with depth.
Answer: First, let's consider a weightless scenario to demonstrate that, for the fluid to be in balance, forces $F_1$ and $F_2$ do not have to be equal.
In the weightless case, according to the Pascal's law, the pressure everywhere in the fluid should be the same.

If we apply force $F_1=P_0A_1$ to the left piston, while the right piston is fixed, it is easy to see that the same pressure $P_0$ will be at points $A$, $B$ or $C$. The pressure force of the fluid acting on the right piston, $F_2=P_0A_2$ will be determined by the pressure under the piston, $P_0$, and the area of the right piston. So, it won't depend on the area of the left piston and will be different than $F_1$, while the fluid will be in balance.
If we add gravity, the weight of the fluid will cause the pressure increase with depth, but, at any given depth, according to the Pascal's law, the pressure will still be the same. We can also see, that, if the horizontal pressure was not the same, the fluid would move from higher pressure areas to lower pressure areas. It should be rather obvious then, that to maintain the same pressure at any given depth everywhere, the heights of the left and right columns, which determine the pressure under them, would also have to be the same. Hence, the pistons have to be at the same level.

My last point should answer your implied question: how come we have two unequal forces, $F_1$ and $F_2$, acting on the fluid "from two different directions" and the fluid does not move? Is it a violation of the Newton's second law? It is not, if we consider all forces acting on the fluid, including the reaction forces from the walls. This should be clear from the diagram below and should be easy to prove, since we know the pressure at all points.

Pascal's law misunderstanding


What's enderpearl's speed in minecraft?

Question: I'm working on a calculator for enderpearl trajectory calculation and I need to know at what speed enderpearls are travelling through air.
Comment: You want to make a calculator mainly based on one number and you don't have that number? :D Anyway, can't you find it out with experiments? Sure, an exact number would require looking into the code, but if it's something point nine nine, you can assume it's the rounded number.
Answer: Enderpearls can have any amount of speed, they follow the same rules as any other object such as snowballs. Throw it up, and it will slow down. Speed it up with pistons and TNT and it will travel much faster.
For reference, steve will throw enderpearls at around 23m/s when taken an average of a normal throw (to be precise when thrown at a 15 degree angle the average travel speed of steve is 23m/s).
However, the fastest pearl cannon ever build achieved 3,000 m/s with an enderpearl.
Reference

What's enderpearl's speed in minecraft?


Hebbian theory "fire together" clarification

Question: Donald Hebb states it as follows:

"Let us assume that the persistence or repetition of a reverberatory activity (or "trace") tends to induce lasting cellular changes that add to its stability.… When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased."
  Or we can conclude in short: "Neurons that fire together, wire together".

As I understand it, this means that synapses that already exist become stronger between neurons.

Could new synapses form between neighboring neurons that "fire together", but are not necessarily directly connected through an axon?
And if so, what is the mechanism to direct the new synapse formation towards that other neighboring neuron that "fires together"?
Answer: Strictly stated, Hebb's rule applies only to existing synapses, and not to the formation of new synapses. (This answer applies to biological neurons, not to ANNs).
Synapse formation is a topic of active research. During development (and in fact continuously even during adulthood), many synapses are created and destroyed. It is not unreasonable to suspect that a similar form of rule is used to decide which synapses are removed and which should remain.
Synaptic connections between neurons show a good deal of specificity -- for example, in the projection from the retina to the optic tectum, synaptic connections are made only with target neurons at an appropriate retinotopic location. This happens because growing axons follow molecular gradients.
Within a cortical column, some possible connection pathways seem to be actively sought -- for example, axo-axonal cells connect specifically to the axon initial segments of target neurons. Neurons certainly have membrane molecules that could be used to identify target cell classes.
So there are probably a number of rules used to determine when a new synapse is made. However, I am not aware of a mechanism for a pre-synaptic neuron to detect how a putative post-synaptic parter is firing, without a synapse already being present. So it seems likely that some form of random process is involved to form new synapses with reasonable post-synaptic partners, after which some activity-dependent rule (like Hebb's) could be applied.
Answer: It probably depends on what stage of development the neurons are in and what region of the brain.  If there's not branching still going on, then probably not.  Hebbian learning is generally considered a concept of neuron connections strengthening (more synapses forming and dendritic spines growing larger) and not the initial formation, particularly in artificial neural networks, where a non-zero weight is already assigned to the neurons, and it's just a matter of strong vs. weak connections.
Answer: Keegan's answer is good I gave it an up vote. I want to offer a valid alternative.
Psychology may induce redundant pathways which trigger approximate simultaneous firing of neurons near or in completely different parts of the brain.
Emotionally intense memories can trigger emotions, basically hallucinations of the event, smells and touch based recollections. The pathways work in reverse as well actual sensory input triggering the memory. The more often you delve into your other memories the stronger your abilities to remember those events become it can be very vicious or pleasurable.
Comment: (-1). This answer could benefit from improved grammar and syntax. Additionally, it's difficult for me to understand the relevance with the question, even after reading it several times.
Answer: Hebb himself (Hebb 2002) actually thought that both the formation of new or the enlargement of pre-existing synaptic contacts (what he called "synaptic knobs") were the most likely possibilities. However, he did not exclude a role for metabolic processes, such as the alteration of intrinsic firing properties of the neuron that could lead to increased synchronicity or a change in the firing threshold, or a limited role for microscopic motility ("neurobiotaxis"). From his language, it is unclear if he had a concept of pre- and post-synaptic elements. Indeed, evidence for the existence of the synapse from electron microscopy were presented about a decade later after the publication of his book.
It is pretty straightforward how the strengthening of pre-existing synaptic contacts can contribute to the proposed model. However, one can also imagine that the postsynaptic element, most often dendritic spines in the neocortex, could actively reach an already active presynaptic bouton. Even if spines are formed completely independently of presynaptic activity, it is still reasonable to think that only those that find an active presynaptic partner will stabilise by forming a synapse. See my answer here for more details on this matter.
Except from the temporal coincidence that is explicitly posited in the famous postulate, Hebb also predicted that the spatial proximity of two neuronal processes could result in synaptic contacts forming or strengthening. The hypothesis of spatial synaptic clustering, as we may call it, is actively investigated with modern methodological tools (Harvey and Svoboda 2007) and it is thought to be important in learning (Fu et al. 2012).

References

Hebb, D. O. (2002). The Organization of Behavior. Routledge.
https://doi.org/10.4324/9781410612403
Harvey, C. D., & Svoboda, K. (2007). Locally dynamic synaptic
learning rules in pyramidal neuron dendrites. Nature, 450(7173),
1195–1200. https://doi.org/10.1038/nature06416
Fu, M., Yu, X., Lu, J., & Zuo, Y. (2012). Repetitive motor learning
induces coordinated formation of clustered dendritic spines in vivo.
Nature, 483(7387), 92–95. https://doi.org/10.1038/nature10844


x11 file manager with photo preview

Question: I organise photos in filesystem directories. I want the ability to preview one photo in a big frame and to preview many photos in grids. I want basic filesystem copy rename move delete operations for directories and photos and other file types.
Comment: Am I assuming right that "x11" means you want this for Linux? And that this functionality must be integrated in a (regular) file manager (not an image viewer that also can browse directories)? If so, what DE (KDE, LXDE, XFCE …) must it work on? What other features must the file manager have? Are commercial solutions acceptable, or must it be open-source and free?
Answer: gThumb
as far as i know gThumb accomplishes all your requirements and even more like easy editing, printing, deduplication and some further features via extensions.
pix
pix is the "platform-independent" fork of gThumb 3.2.8, which will suit your environment better if don't use GNOME3.
Geeqie
maybe also Geeqie as a even more lightweight alternative is worth a look.
Answer: digiKam
What about digiKam? I am using that now for a couple of years and it works quite well. Have a look at digiKam.org
Comment: How do I browse photographs in random filesystem locations outside the library directories?

x11 file manager with photo preview


What statistical test should I use (biostatistics)

Question: I am comparing sperm motility between 2 sets of samples (2 groups). Motility just means weather the sperm are alive or not, in this test I am just looking at that. If its moving, then its alive (I have the motility values as percentages, for example an ejaculate from 1 person might have 20% motile sperm and 80 immotile). It is important to mention that sperm motility decreases with time after ejaculation. I have 2 different groups of people. The control group has had sperm motility (percentage of moving sperm cells in ejaculate) measured in various time periods (1–8 hours after ejaculation). The second group is the treatment group. Here, an extender liquid has been added to the ejaculate which should prolong the motility time (the sperm should stay alive for longer). The sperm motility of this group has been measured later than the control group`s (6–24 hours after ejaculation). I want to test weather the extender liquid has a significant effect on motility over time. How should I approach this?
Answer: One experimental design problem is that you don't have much overlap in the observation times between the two groups. Another problem (maybe less important if you have a lot of specimens), is that each specimen either did or did not have the "extender liquid" added. It seems that it should have been possible to treat half of each specimen with the "extender liquid" for a more direct test of the treatment.
I recommend comparing the two groups at some shared evaluation time between 6 and 8 hours. One could consider a joint model of survival over time that incorporates the treatment as a predictor variable, but the treated group provides no information before 6 hours and the untreated group provides no information after 8 hours. Of course, if the untreated group has exactly 0 survival beyond 8 hours you pretty much have shown the superiority of the "extender liquid" anyway.
An alive/dead outcome ideally should be evaluated by a binomial model based on the observed counts. You have much more confidence in a value of 90% survival, for example, if you have 100 observations instead of 10 observations; the analysis should take that into account. For a single time point (e.g., 7 hours) that would just be a standard binomial test. If you want to model over time, a logistic regression would be appropriate. For modeling over time, if you made multiple motility measurements on the same specimen you would need to take that within-specimen correlation of outcomes into account, e.g. with a mixed model treating specimens as random effects.


Was the significance of Arya's Braavosi coin ever explained?

Question: Jaqen H'ghar gives Arya the iron coin, she can apparently give it to any Braavosi and say Valar Morghulis and that gets her where she needs to go, but why?
Where do these coins come from and what do they indicate to a Braavosi?
Comment: Unless you have the 6th book, I'm safe.
Comment: Yes, it was explained later on. Are you sure you want to be spoilered?
Answer: Yes, in the books,

 Arya gives the coin to the captain of a ship from Braavos. The captain is astonished:

 "Valar dohaeris," he replied, touching his brow with two fingers. "Of course you shall have a cabin."

and

 The captain gives her free passage to Braavos, a cabin, and drops her off at the Faceless Men's temple. Also during the voyage many of the sailors and even the Captain ask her to learn and remember their names, and many seem afraid of her.

Based on this reaction, it seems the coin and saying are a custom that a Braavosi expects only from one of the Faceless Men, such as Jaqen H'ghar.
Answer: A theory is that a Faceless Man cannot kill one of his previous friends, or a person they know from their life before the temple. Therefore, the Bravosi are eager to help Arya in order to befriend her, so if she is ordered to kill them further on, she won't be able to. That's why they ask her to remeber their names.
Comment: "I know this man, I cannot give him the gift"
Comment: IIRC, this is not just a theory but actually stated by the Faceless Men in one of Arya's chapters.
Comment: I've read so many theories, that I honestly cannot remember sometimes if I've read them in the books or on the forums :)
Comment: No worries, there's a *lot* going on in this series...
Comment: That theory is wrong IMO. In ACOK, Arya IX, Arya asked Jaqen that if he would kill his own father if Jaqen named him? Jaqen said if Arya knew his father's name and if he wasn't dead already, he would die at her command. Surely he must have known his father.
Answer: It was a distinct coin, one which was associated with the Faceless men. It indicates to the Braavosi that the bearer is either a member of the society or a recruit on his/her way to join them. It is unclear where do these coins come from (Whether minted in the official Braavosi mint or in an exclusive FLM mint) but it is clear that the coins are used exclusively by the members of the society.
It is also unclear that what exactly do the Braavosi get by serving the members of the Order. However it seems to be deeply rooted in the City's culture and traditions. Now let's look at the evidence:

a piece of iron no larger than a penny and rusted along the rim. One side had writing on it, queer words she could not read. The other showed a man's head, but so worn that all his features had rubbed off.
A Clash of Kings - Arya X

I always interpreted it this way that while Arya thinks the facial features are rubbed off because of the coin's age, the man never had a face at all. It was a Faceless man.
When Jaqen gave her the coin, Arya thought that it could be used as currency but Jaqen clarified that the coin is not to be used as currency.

"What is it?"
"A coin of great value."
Arya bit it. It was so hard it could only be iron. "Is it worth
  enough to buy a horse?"
"It is not meant for the buying of horses."
"Then what good is it?"
"As well ask what good is life, what good is death? If the day comes
  when you would find me again, give that coin to any man from Braavos,
  and say these words to him — valar morghulis."A Clash of Kings - Arya IX

If it was just any other piece of Braavosi currency and not a special coin used exclusively by Facelessmen, how would the Braavosi understand what is it and what does the bearer want? Of course one could argue that the coin and the words together would make the coin special but that's evidently not the case as the Braavosi captain immediately realized what the coin was.

"Wait," Arya said suddenly. "I have something else." She had stuffed
  it down inside her smallclothes to keep it safe, so she had to dig
  deep to find it, while the oarsmen laughed and the captain lingered
  with obvious impatience. "One more silver will make no difference,
  child," he finally said.
"It's not silver." Her fingers closed on it. "It's iron.
  Here." She pressed it into his hand, the small black iron coin that
  Jaqen H'ghar had given her, so worn the man whose head it bore had no
  features. It's probably worthless, but . . .
The captain turned it over and blinked at it, then looked at her
  again. "This . . . how . . . ?"
Jaqen said to say the words too. Arya crossed her arms against her
  chest. "Valar morghulis," she said, as loud as if she'd known what it
  meant.
"Valar dohaeris," he replied, touching his brow with two fingers. "Of
  course you shall have a cabin."A Storm of Swords - Arya XIII

The Crew of the Ship then started befriending her and giving her gifts. The Captain asked her to remember the service he had done her. Later the Kindly man at House of Black and White confirmed to her that the coin was the fees she paid to enter the House of Black and White and their training.

"Why would you wish to fight? Are you some bravo, strutting through
  the alleys, spoiling for blood?" He sighed. "Before you drink from the
  cold cup, you must offer up all you are to Him of Many Faces. Your
  body. Your soul. Yourself. If you cannot bring yourself to do that,
  you must leave this place."
"The iron coin—"
"—has paid your passage here. From this point you must pay your
  own way, and the cost is dear."A Feast for Crows - Arya II

The theory however that the Faceless Men can't kill people they knew before they became members of the society however seems wrong. Jaqen H'ghar told Arya that he would kill his own father if Arya knew his name.

"Anyone?" she repeated. "A man, a woman, a little baby, or Lord Tywin,
  or the High Septon, or your father?"
"A man's sire is long dead, but did he live, and did you know his
  name, he would die at your command."
"Swear it," Arya said. "Swear it by the gods."A Clash of Kings - Arya IX

So as evident, it was a special coin used by the Faceless Men. We see two uses for it:

Seeking passage to Braavos from anywhere in the world.
Enrolling in the Faceless Men training program.

That's all of its significance that we know of.
Comment: Regarding the last part - I thought she used an ordinary gold coin dipped in poison, slipped into the insurance salesman's customer's bag of gold? She'd earlier observed that the insurer bit all gold coins he was paid, to make sure they really were gold - so he died of what looked like natural causes, long after Arya had left the scene. Simply *hoping* someone dies of fright doesn't sound like a good plan; worse, the client might see iron coin before paying and think *he* was the target; and worse still, a rare, reliably-deathly-terrifying iron coin would remain at the scene for anyone to take
Comment: @user568458 Oh you are quite right. Apparently I interpreted it wrongly this whole time. The heart gave out due to poison, not fear. Cheers.
Comment: @user568458 you've blown my mind.
Answer: Valar morghulis (all men must die) is the motto of the Many-Faced God and his followers which are assasins.
Spoiler for the TV series, already happened in the books:

 The coin together with the quote allows Arya to get passage to Braavos and entrance into the temple of the Many-Faced God.

Source
Comment: Coins from Braavos and knowledge of High Valyrian and the quote are quite rare in Westeros. And together yes, they just mean that.
Comment: What's it mean though, does having a coin mean you're an associate of Jaqen's group?  Apparently I can't hide spoilers in comments.  Anybody noticed its kinda hard to talk about Game of Thrones w/o possible spoilers?  We need a SciFiSpoilers.stackexchange.
Comment: I suspect that "valar morghulis" can also be correctly translated to "everyone dies".
Answer: A coin of significant value which allow holder to reach temple of faceless god and only there. Remember Arya first told the captain to take her to nights watch but captain refuses.
Answer: The significance of the coin is that it is not really a "coin" at all... meaning a medium of exchange holding an intrinsic value. Instead it is a "recognition token" signifying membership in an elite and secretive assassin's guild. Think mafia hit-men crossed with ninjas and throw in some 007 and a little majick. Arya of course does not know any of this, she just thinks it's a worthless coin at first... and so the ship's captain must have been peeing himself while thinking... "THEY'RE USING LITTLE GIRLS NOW!!!"... because everyone now assumes that she's an assassin. The coin is iron because that is the lowest value metal... the value of the coin is explicitly NOT in the metal, but in the fact of the bearer holding it. We can presume that they are made by the Faceless Man organization and handed out as field equipment to operatives. Note that Jaqen had been searched and in chains when he first gave the coin to Arya. This tells us that the coin must be small, so that he could have kept it hidden from searchers. She first believes the coin to be very worn, which is why she cannot see the face of the portrait... but later realizes that it is not so worn after all, and the vagueness of the face is part of the design. This tells us that it must be a FACING portrait... because a profile remains recognizable even when badly worn. Shire Post Mint makes just such a coin under license with George R.R. Martin... and George carries them around to cons and movie sets and hands them out to people.
Answer: It appears as though the coin is special and comes from the House of Black and White. In addition to the book answer over there the show also appears to use different props for the Braavos coins to the one Arya is given.

Arya with her coin.
And in the following video around the 2:05 mark you see some coins on the table:

Obviously these could be different amounts but the design seems totally different and in currencies there is usually some consistency.
The coin then appears to indicate that the person wielding it, along with the phrase "Valar Morghulis", is either from the Faceless Men or needs transport to their location. This is witnessed when the Braavosi captain gives Arya passage to Braavos just from showing the coin and stating the phrase:


How can I attach a pdf in salesforce email,edit the email body and the changes will reflect in atached pdf?

Question: I want to attach a pdf in a salesforce email by selecting an email template.I have created one visualforce template by which I am able to attach the pdf to the mail.But my requirement is user can edit the email body like the html template and the attached pdf will get refreshed reflecting the changes,Appreciate your help!
Comment: Can you make a (large) text field on the object, call it "Email Notes" or something? They'd have to fill it in before they click "send an email & pick template" though
Comment: If I will make any large text field.How it can be used as a email template?
Comment: By simply using the field APi name in that template, like any other field coming from the object? `{!relatedTo.Email_Notes_field__c}` or something... Just put this reference both in the email body and in the PDF attachment's section.
Comment: We need to provide user to edit the template as in case of html template.I deisgned one visualforce template with email body and attachment.Things are working fine.When user select a template pdf is getting attached to the email.But user will not be able edit the visualforce template.
Answer: Make the email by rendering a Visualforce page as a pdf. There is lots of sample code if you search Developerforce for Email - with quote2pdf, sending SingleEmailMessage, and more.


What starts the login prompt in RHEL?

Question: I don't have a service in my run level that starts the login prompt, so I was wondering what does.
Comment: Could it possibly be in the rc.sysinit file?
Comment: In Debian, its in `/etc/inittab`. Might be the same on RedHat.
Answer: By 'login shell' you mean the login prompt you get when you hook your server up to a keyboard and monitor? And the same login shells on the other virtual terminals accessed with CtrlAltF2 and so on?
On RHEL 4 and 5, they are started in /etc/inittab, look for the lines that say mingetty. The inittab man page will explain what the lines mean but it goes in the format like id:runlevels:action:process. You can comment them out or add new ones and run telinit q to have it re-read it your inittab.
On RHEL 6, they are started in /etc/init/tty.conf with the ttys defined in /etc/sysconfig/init. If you look at /etc/inittab it actually gives an short explanation but Red Hat has an explanation on their website too. RHEL 6 switched to upstart for RHEL 6 which is why it is different (don't be confused by the fact upstart is on the Ubuntu website, it was started by Ubuntu but other distros use it too).
Edit: init is the first process started by our OS, it is what spawns all of your services. It has a PID of 1. When it starts it reads /etc/inittab and if you look at the lines that say reference rc with some number, that is what is starting your services at your desired run level. It likewise makes sure mingetty is running at your desired levels on your desired devices. You can read more on the the init section of wikipedia's article on how linux boots and this article on from power to bash.
Comment: At what point is this process started?  Does it start after the services in your run level directory or before?
Comment: @sqenixs After. The scripts in the "run level directory" are executed when the runlevel changes. After the new runlevel is established, `init` starts the runlevel's permanent fixtures.

What starts the login prompt in RHEL?


Could an asteroid impact cause radioactive fallout?

Question: Could a (regional or global) fallout of radioactive material be a "bonus" disaster effect of an asteroid impact? My reasoning for how such a scenario maybe could be possible:
A) Some asteroids maybe consist of lots of radioactive heavy metals because they were initially formed by ejecta from the cores of planets during planetary collisions. Maybe even an airburst of a rather small such an asteroid could cause widespread dangerous radiak fallout?
As I understand it, Earth's initial uranium has fallen into the core. The uranium mines dig into concentrated deposits of uranium in the crust which came from uranium rich asteroids.
B) If any kind of asteroid large enough hits a uranium rich part of the Earth crust (making it the second one on the same spot), it could maybe eject much of Earth's own uranium and thus cause a dangerous fallout?
Answer: I'm not aware of any relevant uranium ore deposit, which is related to meteoritic material.
Dangerous fallout is by far the most caused by short-lived radioactive isotopes. Those isotopes are rare in meteorites as well as in rock on Earth.
Natural nuclear reactors, which would produce short-lived radioactive isotopes, don't occur any more on Earth, since the natural U-235/U-238 isotope ratio is too low, now. This is due to the half-life of U-235 of about 713 million years in contrast to 4,468 million years for U-238.
If an asteroid would impact into a uranium ore deposit, most of the molten ejected material would fall back to Earth as tektites.
Evaporated ejecta and aerosols (dust) would probably increase health risk for some time, until it's washed out from the atmosphere. But other, less-radioactive aerosols would be a health risk, too.
Comment: Thanks! Iron-nickel meteorites (http://en.wikipedia.org/wiki/Iron_meteorite) probably come from asteroid/protoplanetary cores. Iridium is probably most famous for its abundance in meteorites. Uranium is used for age estimates of meteorites. But for mining, deposits formed by geologic processes, usually are the first choice. Might be, the claim is related to the georeactor hypotheses (http://www.geoneutrino.nl/Publications/RadPhysChem-georeactor.pdf).
Comment: @LocalFluff More on the origin of uranium: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Uranium-Resources/The-Cosmic-Origins-of-Uranium/
Comment: Great answer! Do you have any comment about whether uranium ores mined today really have come to be concentrated because of uranium rich asteroid impacts? I have heard this claim but I can't easily find confirmation. Are there asteroids which are much richer in heavy metals, for example those asteroids which come from planetary cores after planetary collisions (if such ejecta is feasible)?
Comment: A far more likely source of fallout is from humans with itchy trigger fingers launching nuclear weapons when a city suddenly disappears in a cloud of plasma with no warning.
Comment: Perfectly agree... Those ruling the armies are not necessarely a very elevated homo sapiens ...
I hope Nibiru will be mild...


Knockback when shooting

Question: I am currently working on a shooter and I could use some help with this. I want to make my character knock back when he shoots, but also the knock back should be different when the player uses a different weapon. How can I do this?
Comment: This is difficult to answer without information about how your player movement works at present. If you're still looking for help with this, please consider adding the relevant portions of your player movement script so users can understand what they have to integrate with. There are lots of ways to move a player, and each can require different knockback strategies to ensure one behaviour doesn't override or mix badly with the other.
Answer: It sort of depends on the game engine you're using, but you can accomplish this effect by adding some relative force in the opposite direction of your character.
For each weapon, you will designate some force for the variable, and when you fire, apply that amount of force to your actor.
To add a little more cool effect, you can even make the camera shake some, or add some recoil to the camera.
If you're using Unity, for instance, you can check out RigidBody.AddRelativeForce documentation. You'd add the force on the Z axis, in the opposite direction.
Comment: I added the Unity tag so I am using Unity
Answer: Just animate the knockdown behaviour, create different animations with different weapons in some software like maya, blender etc and use it directly in Unity.
Unity uses Mechanim in which you can blend different animations in a same state. Although blending is used to blend two or more similar motions but it can also be used to play different animation in same state in different scenarios.
Tutorial for blend trees can be found here.

Knockback when shooting


Can you craft watches?

Question: Can you craft watches in the mobile version of Terraria? Even with a lot of gold and chains, while at a table and chair, I still can't make one.
Comment: It should be craftable.  [Here's the wiki link](http://terraria.gamepedia.com/Gold_Watch), and it doesn't say PC specific.  You may need to put up a screenshot, with your crafting/inventory open, to see what the issue is.
Comment: Actually right now watches gps phones and depth meters are all useless in mobile. They didn't write the functions in the script but keep them in chest incase they do add the functions.
Answer: Are you at a TABLE and a chair, or are you next to a WORKBENCH and a chair? It's specific when it comes to that stuff. If your near a workbench and a chair then it won't work.
Comment: It's not possible to craft watches in the mobile version FWIW.
Answer: No. It is not possible to craft watches in Terraria mobile version. I have the same problem. I hope they make it possible soon though.

Can you craft watches?


How do the different types of materials used in Ethernet cables affect reliability?

Question: There are many metals used in different types of network cables, such as aluminum and copper. Some are expensive and some are cheap. What scenarios constitute the use of these types of different wire materials?
Comment: I suggest improving this question; Give some examples of the "many metals" you see used in cables. Perhaps a specific example of a low-end and high-end cable and ask the difference between them. NE community should then be able to give the technical differrences.
Comment: Other factors within a given metal also come into play such as solid vs stranded conductors.
Comment: Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
Answer: metal
Aluminum is less expensive, but will develop cracks if it is flexed too many times. Copper is more expensive, but is more ductile; So it is much more forgiving of being repeatedly flexed.
specifications
The Cat-N specifications determine various limits; Parameters such as:

how much a signal may be attenuated per unit of distance
how much cross-talk (signal leaking from one pair to another) is allowed between the pairs
how much radiation ("leakage" of the signals) is allowed from the cable
the range of frequencies which the cable's pairs are designed to carry

(and much, much more...)
use cases
There are differences in the insulation which jackets the conductors and the entire cable. For example, "plenum" cable -- meaning it is designed to be used in a plenum, a space within a building which is part of the air handling path for climate control -- is designed to limit how much, and at what temperature, it will emit toxic fumes.
There are options such as full length shielding (grounding) which prevents interference from other sources. (This is not common with Ethernet cables.)
The overall physical diameter of the cable may be a use case limiting factor. If you are install a very large number of cables, that might matter.
Some cables contain a "strain relief" feature; A small nylon string (looks like dental floss) can be added within the cable to help prevent stretching the conductors when cables are pulled into place.
Answer: This is more of a physics question than a networking question actually. Different kinds of metals have different physical characteristics, such as durability (can it rust/degrade?), conductivity (how much does the signal degrade per meter?), flexibility (does the inner cable easily crack?) and sensitivity to interference/crosstalk.
Network cables all carry a Category specification, which roughly groups them in how fast they can reliably connect two endpoints over a maximum distance. Cat5e for example is specified to be able to carry a 1000BASE-T (Gigabit) signal up to 100 metres per segment, with tighter crosstalk specifications than its predecessor Cat5.
While different metals might change a cable's category, the category only specifies rough minimum characteristics, such as impedance, resistance, propagation speed and even operating temperature range. Within a category you could still have notable differences in cable pricing for improvements on specific characteristics that do not make it fall in another category yet.
Answer: Excluding plenum-rating & speed, if any of this matters you probably should already be using fibre.
For EMI, grounding, etc. fibre is cheap insurance even when it's not strictly necessary.
For distance, if it's even possible you're running up to distance limits you should switch to fibre (obviously this doesn't really work with access runs). For access I'd try and stay on the conservative side of distance limits and verify runs with a certification tester. As long as you're on cat-5e or better you're fine for speed, although the better ratings do increase the distance limits on gig, but again you should be running cable certification tests if you're likely coming up on those limits.
Answer: The reliability of copper Ethernet cables is defined by Category -- such as Cat3, Cat5, Cat5e, Cat6, etc. The higher the category, the higher the reliability (and therefore the higher allowed speed standard). Higher categories represent more twists in the cables per foot, which alleviates crosstalk and EMI interference. For example, Cat5e cable has more twists per foot than Cat3, which is what allows gigabit Ethernet to work with Cat5e but not Cat3.
It should be noted that Ethernet does not always mean copper Unshielded Twist Pair cables. Ethernet is an OSI Layer-2 concept with different acceptable Layer-1 standards (such as fiber optic cables).
Comment: I edited OP's reference to 'Ethernet cables' to 'network cables'. There's also STP by the way for which this **is** relevant.
Answer: Aluminium is cheaper than copper but has higher resistivity and is more prone to unreliable terminations. Copper clad aluminium is an attempt to get some of the advantages of copper while keeping the price down. It's a clever idea in theory (in a high frequency system most current flows in the surface of the conductor anyway) but it's nonstandard and i've seen reports that it is unreliable in practice.
The categories of cable are mostly about the high frequency performance. Higher categories have better high frequency performance. This is acheived through higher twist rates (which better reject high frequency capactive and inductive coupling), higher quality materials, more careful control of the geometry and in some cases shielding. The category you need will depend on the speeds you are operating at and the distance you are operating over.
I would generally suggest going for cat6 solid copper cable for installation wiring to end devices, it's not terriblly expensive will support 1000BASE-T with ease ans on short runs should support 10GBASE-T . If you want to run 10GBASE-T on long links you might want to splash out on cat6A but last I checked it was substantially more expensive than cat6 and it's not clear if 10GBASE-T will ever become more than a niche product.
For backbones I would seriously consider fiber at this point.


The Extensions: Install page is empty in 3.6.2 Admin

Question: I've updated Joomla to 3.6.2 in the past month on a site. I'm looking to update Akeeba Extensions but I don't have either the side menu or upload box in the Extensions: Install page. I have reinstalled core files from Components > Joomla! Update and also checked the database is up to date.
Answer: I was using Firefox on Mac and found an error in firebug about a local storage file being corrupt. (NS_ERROR_FILE_CORRUPTED) This seemed to prevent the form and menu from showing. Switching to Google Chrome resolved the issue for me.


Compile vim with python3 support in Windows

Question: I'm used to Ubuntu and know how to compile and edit vim. But how can i compile vim with python3 support on windows ?
Prefer to do it from the terminal. But i don't mind if i need to do it with miniGW if thats a better option.
Answer: You can find the instructions to build Vim on windows in the source file src/INSTALLpc.txt.
More specifically in the section 8. Building with Python3 support you can read:

8. Building with Python3 support
================================

For building with MSVC 2008 the "Windows Installer" from www.python.org
works fine.  Python 3.6 is recommended.

When building, you need to set the following variables at least:

    PYTHON3:         Where Python3 is installed. E.g. C:\Python36
    DYNAMIC_PYTHON3: Whether dynamic linking is used. Usually, set to yes.
    PYTHON3_VER:     Python3 version. E.g. 36 for Python 3.6.X.

E.g. When using MSVC (as one line):

    nmake -f Make_mvc.mak
        PYTHON3=C:\Python36 DYNAMIC_PYTHON3=yes PYTHON3_VER=36

When using msys2 and link with Python3 bundled with msys2 (as one line):

    mingw32-make -f Make_ming.mak PYTHON3=c:/msys64/mingw64
        PYTHON3_HOME=c:/msys64/mingw64
        PYTHON3INC=-Ic:/msys64/mingw64/include/python3.6m
        DYNAMIC_PYTHON3=yes
        PYTHON3_VER=36
        DYNAMIC_PYTHON3_DLL=libpython3.6m.dll
        STATIC_STDCPLUS=yes

(This is for 64-bit builds. For 32-bit builds, replace mingw64 with mingw32.)

You may also want to look at the instructions in src/INSTALL.txt
Comment: using `make`, as long as it's installed with MinGW, works as well. Also, in case anyone else gets stuck on the same problem: `make` needs to be executed in the `src` directory, not the root directory.


Microdisplacement skewed image

Question:
Hi, I´ve been trying to get a microdisplacement on a plane from a .jpg 8 bit and a 16 bit .png with a resulting skewed image. How do I fix that?
Thanks.
Answer:
Check that a displacement node is used before displacement and that your preview and render options allow for 1 pixel detail. Max subdivisions allows your displacement to be further refined at render time.
Don´t forget to add a displacement modifier on simple mode and check adaptive.
Comment: It's worth pointing out that the Blender version is 2.79.4 - presumably a development build - and the Displacement socket is now a Vector rather than a Scalar value. The new Displacement node allows you to generate the displacement vector to mimic the old Displacement socket behaviour.

Microdisplacement skewed image


Electrical Engineering/Telecommunications/Power Amplifiers VSWR and harmonics

Question: How does VSWR at a power amplifier output affect the level of harmonics? and is there any textbook or paper which addresses this issue?
Comment: Does VSWR stand for **Voltage Standing Wave Ratio**?
Answer: If VSWR = 1, then voltage on the output amplifier is the "lowest" and RF matching is ok (RF amplifiers are designed delivering "always" maximum power on load). If VSWR gets higher, then voltage on output of amplifier may also be higher "some time" because of the reflected wave. And if it is higher, it can cause higher non-linearities (by clipping and/or breakdown)... Some solid RF amplifiers are protected through special circuitry which measure VSWR and protect them as soon as possible (quasi instantaneous).


Display multiple images from outside the public folder

Question: Im working on a project, where I'd like to store photographs in a secured location for copyright reasons. Users can upload their photographs to a folder, outside the public route ('www').
For signed-in users, I'd like to allow to browse these photographs.
I wanted to use 'imagecreatefromjpeg' and 'imagejpeg', but they could only fill the entire webpage. That would only be good, if I would want to open the images into a pop-up window.
Instead of doing that, I'd like to have small thumbnails (generated on upload, also stored in private folders) all over my screen.
Is there any way to do that?
Am I going in the worng direction with this?
Thanks for helping me out.
Comment: Not loading images via appropriate `` tags inside proper HTML will do such things...
Answer: You can cache thumbnails of the submitted images with php gd
http://www.fliquidstudios.com/2009/05/07/resizing-images-in-php-with-gd-and-imagick/
Then create a image.php file that will serve images (put in your own authentication to secure access) that will end with imagejpg($im).
Then in your html, just put something like:


"Disperse" VS "Scatter" VS "Break up"

Question: According to dictionary explanations, as both transitive and intransitive verbs, all the three options below mean the same thing when it comes to make a crowd or people leave a place or when they leave a place themselves.
Disperse:
if a group of people disperse or are dispersed, they go away in different directions:

Police used tear gas to disperse the crowd.

Scatter:
if a group of people or animals scatter, or if something scatters them, they move quickly in different directions:

The sound of gunfire made the crowd scatter in all directions.

Break up:
to make people leave a place where they have been meeting or protesting

Police moved in to break up the meeting.
The crowd broke up slowly.

Then, I was wondering if they are interchangeable in the following examples. If they aren't please let me know why as almost all reliable online dictionaries have defined them as quite close synonymous words in this case.
1 - Police ........ the crowd.
a. dispersed
b. scattered
c. broke up

The protesters .......... at almost 6 o'clock.

a. dispersed
b. scattered
c. broke up
I think, they all mean the same in this sense and can be used interchangeably in either case above. However, I have my doubts and need someone let me know about it.
Answer: To me, "dispersed" is a more polished word than "scattered". Also, "scattered" tends to imply being in a hurry and in fear, e.g. rats scattered when they saw the cat. So either word can fit both sentences, just depends on how you want to portrait the police and the protesters.
"Broke up" is different than the other 2 words. It focuses on the initial splitting up of the crowd, but the other 2 words focus on the spreading out of the crowd.

"Disperse" VS "Scatter" VS "Break up"


Validating slope (s) in secp256k1 elliptic curve

Question: knowing the coordinates of $R$ on secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?
Answer:
Knowing the coordinates of $R$ on secp256k1 and an integer $s$, how do we validate that $s$ is the slope at the point $Q$ on secp256k1 such that $R=2Q$ ?

One way would be computing $Q=((n+1)/2)R$ by point multiplication as in this answer, then computing the slope at $Q$ and comparing to $s$.
But there's a better way. From point doubling equations we know that
$$\begin{align}s&=(3Q_x^{\,2})/(2Q_y)&\bmod p\label{fgr1}\tag{1}\\
R_x&=s^2-2Q_x&\bmod p\label{fgr2}\tag{2}\\
R_y&=s\,(Q_x-R_x)-Q_y&\bmod p\label{fgr3}\tag{3}\end{align}$$
I suggest this procedure, which starts from $s$, $R_x$, $R_y$ only.

check that $0<s$ and $s<p$
check that $R$ is on secp256k1, that is $(R_x^{\,3}+7-R_y^{\,2})\bmod p=0$
compute $Q_x=(((n+1)/2)(s^2-R_x))\bmod p$ (which follows from $\ref{fgr2}$)
compute $Q_y=(s\,(Q_x-R_x)-R_y)\bmod p$ (which follows from $\ref{fgr3}$)
check that $Q$ is on secp256k1, that is $(Q_x^{\,3}+7-Q_y^{\,2})\bmod p=0$
check that $(3Q_x^{\,2}-2s\,Q_y)\bmod p=0$ (which follows from $\ref{fgr1}$)

I'm not sure step 6 is necessary; it may be redundant with 5.
If we omit step 1, then adding $p$ to a valid slope can yield an $s$ that the other steps will accept, even though that $s$ could not be obtained as s = (3 * Qx**2) * pow(Qy*2, -1, p) % p as in the definition of slope given in the original version of a related question.
I made an example implementation in Python. Try it Online!
Comment: The procedure you provided is one way it can be done but am looking for a approach that involves only $s$,$R_x$ and $R_y$. Can you give more insight on step one $0<s<p$
Comment: I added explanation on step 1. My procedure involves only $s$, $R_x$ and $R_y$ (notice that $Q_x$ and $Q_y$ are recalculated from that, and form $p$).


Can moderators see an email address I removed from my account? How can I prevent this?

Question: My main Stack Exchange account has been using an email address that puts me at risk of leaking sensitive private data about myself. Although I hid the email, I just very recently discovered that moderators of the sites can still access the email address. As I do not want anyone to see it, I changed the email address entirely. I would like to ask if moderators can still see my past email address? If yes, will the deletion of the account be sufficient (hopefully I can keep my account)?
Comment: @Ollie while related that states nothing about previously entered emailadresses. My gut tells me that changing won't wipe the previous entry completely. Question then remains to whom it would be visible. SE employees or moderators as well?
Comment: I would like an official's answer if a mod can see such info, as I tried in my mod tool to see in the user history, I can't see what the user changed, but I wonder if I could see it. I have no dummy account to change the email to validate the information
Comment: Agreed @yagmoth555, an official answer would really be welcome.
Comment: You might want to read through the following question: https://meta.stackexchange.com/questions/341932/a-users-original-email-address-is-retained-in-the-system-even-after-theyve-cha
Answer: I think your best bet would be to send a GDPR request, to ask SE to remove your previous email completely. You can do so via this form: https://stackoverflow.com/legal/gdpr/request
While the law that forces SE to adhere to this is a European one, I have no hints that they limit this to European citizens. AFAIK they will also effect request made by other nationals.
Answer: I'm not sure if it's still the case, but it used to be the case that moderators could also see previous emails.
There are various events that are logged in a user profile history, changing your mail address was one of those events. Moderators can view this history for every user on their site.
You also should make sure that the login method you use, whether it is an SE account or e.g. a Google account also uses an Email you're comfortable with moderators or SE employees seeing. This is not related to the email setting of your SE profile, but a separate thing. You can see your logins on your profile edit page under "my logins".


grub is not showing after installing ubuntu 16.04 LTS on windows 8.1

Question: I have installed Ubuntu 16.04 LTS alongside windows 8.1 on my dell inspiron 3551 laptop with USB.
The installation process is successfully done. And then it ask to restart the computer.
when i restarted the laptop then it doesn't showing the grub it directly opening windows operating system.
Comment: If pre-installed Windows 8, then system is UEFI. Did you install Ubuntu in UEFI boot mode? And can you boot use f12 to choose Ubuntu entry?  https://help.ubuntu.com/community/UEFI Also make sure Windows fast start up is off, before booting into Ubuntu. Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
https://help.ubuntu.com/community/Boot-Info
Answer: You should check, what works in BIOS-settings of your machine:
Reboot your machine and press key 'F2' (or key 'F12'?). Then you are in settings of BIOS. Check there the booting-order in menu of "boot". There you can put your hard-disk at first place in first line.
Then exit and save settings. Reboot and good luck.
When Windows is still booting first, you should edit the grub entries.
This is explained here and duplicate of this link here:
How do I change the GRUB boot order?


Are there any quantities defined analogically to the virtual temperature, but for other gases?

Question: The virtual temperature is a pseudo-temperature taking into account water vapour in the atmosphere in such a way, that the resulting quantity can be used with the ideal gas law and the molar mass for dry air.  Although the most significant in the troposphere, water vapour is not the only trace gas for which the concentration varies through the atmosphere.  Are there any similarly defined pseudo-temperatures, taking into account varying volume mixing ratios for other trace gases?
Comment: I liked your comment about methane atmospheres on titan. Without knowing much about the topic, it looks like those equations are suitable for any vapour. Is it the case that for calculations in the earth's atmosphere they're just used for water, because that's the only really significant atmospheric vapour for the purposes of CAPE?
Comment: @naught101 Yes, other gases have a negligible impact on the mass of an air parcel, I think.
Answer: It is true that water is not the only variable constituent of the atmosphere, but it is capable of large variations (0-5%+) that I'm not sure other trace constituents are capable of outside of plumes from smokestacks / cars / factories / etc.  A virtual temperature for other gases would only be meaningful if their variability imparts a significant change in mass in a parcel such that it becomes important for buoyancy.
That being said, you could easily derive such a virtual temperature, as the virtual temperature is just a proxy for density changes and we can easily calculate this.
For each constituent gas, you can use the ideal gas law as
$$p_i = \rho_i R_i T$$
such that each density of gas $i$ is
$$\rho_i = \dfrac{p_i}{R_i T}$$
and then sum these with dry air ($p_d$)
$$\rho = \dfrac{p-\sum p_i}{R_d T} + {\large\sum} \dfrac{p_i}{R_i T} $$
and then solving for $p$ in terms of $\rho$, $R_d$ and collecting the rest of the terms into a variable and calling it $T_v$.
This process could be used to generically define a virtual temperature for any number of trace gases (single or multiple) as long as you know their mixing ratios with dry air.  I'm not aware of anyone using (on Earth) a virtual temp for anything other than water vapor and suspended hydrometeors (e.g. density potential temperature, $\theta_\rho$) but that certainly doesn't mean no one is.


If we execute kernel programs in the user mode and user programs in kernel mode what are some consequences

Question: Question on operating system
If we execute kernel programs in the user mode and user programs in kernel mode what are some consequences
Answer: Assuming a monolithic kernel like Linux, there just are no "kernel programs", every in-kernel thread is just a function running in the kernel's address space. If you copy that and place it in a userland program (given the correct environment in terms of available data structures and functions to call) it will work fine as long as it doesn't invoke any privileged operations. Any of those will give some sort of exception.
Placing a userland program into the kernel would mean to add a lot of infrastructure provided by the operating system: in C's terms, standard input and output, the contents of the standard C library and any others in use. Using a snippet of userland code in the kernel will work just fine, as long as any infrastructure/environment called upon is provided.
Kernel code and userland code are the exact same instructions (but the kernel has access to some privileged operations and registers that userland can't use).
Comment: Many modern operating systems have the possibility of running the kernel as a user process, for various use cases: kernel development, testing, simulation, containerization etc. Some examples are User Mode Linux and the the DragonFly BSD Virtual Kernel.


Interfacing with an LCD screen

Question: I have managed to salvage the LCD screen from an old Tom-Tom (the model number of the screen is LTE430WQ-F0B-0BS). It comes with a driver for the screen on the back, but it doesn't look humanly possible to solder/interface with it in any way. However, this driver connects to 4 wires going into the LCD, which look easy to solder. I was wondering whether it'd be possible to skip the driver already there, and simply connect the 4 wires to the GPIO of an Arduino or something similar. I have looked for some time for this solution, but only found data sheets which referenced the on-screen driver.
Answer: Those 4 wires do not go to the LCD, but to the touchscreen. It is most likely a 4-wire resistive touchscreen.
Comment: I'm not sure what you mean. You would want to interface with the driver. The driver has hundreds of pins that connect directly to the rows/columns of the LCD, so the most feasible way to communicate would be to sever the connection between the TomToms controller and the driver, and try to talk to the driver directly using the Arduino.
Comment: Is there any way to get past the driver?
Comment: Ok, that's a good point. But, the wires on the driver are extremely small. Do you have any tips on how to connect them to an Arduino?
Comment: It would be really difficult to access the pins. I think this kind of thing falls into the category of not-worth-the-time-to-hack, especially considering you can just get a color LCD shield on eBay for like ~$20. The TomTom screen driver will likely need more than 10 pins because the data is sent parallel for speed reasons, and it will be a nightmare to bring those pins out to the Arduino.
Comment: Yes, that's very true. Looks like I'll just have to buy one. Thanks for your time :)

Interfacing with an LCD screen


How to use external scripts e.g. jquery for YouTrack Workflow scripts

Question: I want to clean the comments from youtrack by scheduler in a for Each loop with:
action: (ctx) => {
    var issue = ctx.issue;
    issue.comments.added.forEach(function(comment) {

    // https://stackoverflow.com/questions/822452/strip-html-from-text-javascript
    comment.text = jQuery(comment.text).text();

    });
  },

But I get the error: jQuery is not defined.
How can I include jQuery in the script to use it to clean the comment from HTML tags.
Answer: It is not possible to use jQuery inside of a workflow script. Still, you can create a helper function that does the trick:
function cleanComment(text) {
  return text.replace(/(<([^>]+)>)/gi, '')
}

and use it inside of the action part of the rule
Comment: https://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454