How do I use a custom stopwords filter in the Java Weka API?

Question: I am using the Java Weka API to build a classification model. I can use the builtin stopwords filter. However, I need to use a custom filter for my problem. I do not know how to use a custom stopwords filter in the Java Weka API.
Answer: First of all you have to prepare a text file for your custom stopwords. Then you can use the following code:
import weka.filters.unsupervised.attribute.StringToWordVector;

StringToWordVector filter = new StringToWordVector(10000);
filter.setStopwords(new File(".../stopwords.txt"));

Hope it will help you.
Comment: I appreciate your support.
Comment: I am very new in Java weka-api programming. I do not understand clearly. Anyone please provide me little more elaborate answer. Thanks in advance for your support.
Comment: Please let us know which part do not you understand?
Answer: You can try the following code.
import weka.core.converters.ConverterUtils.DataSource;
import weka.filters.unsupervised.attribute.StringToWordVector;
import weka.core.Instances;

Instances data = DataSource.read(".../document.txt"); //Your document .
filter.setInputFormat(data);
StringToWordVector filter = new StringToWordVector();
filter.setStopwords(new File(".../stopwords.txt")); //stop words file.
Instances data = Filter.useFilter(data,filter);

You can also read the following document for better understanding of the Weka API for Java.
http://weka.sourceforge.net/doc.stable/
Comment: I appreciate your support. Thanks a lot. Your code and the link of the document really help me lot.


Which ayah in the Qur'an was the last to be revealed?

Question: What are the candidates (and evidences) for ayaat which are claimed to be the last one revealed? I've heard so many opinions over the years, from Ma'idah:3 to Baqarah:281 to Surat Nasr and a few more.
Answer: There is no general conclusion on the matter. It depends, really, on who you ask.
If you go by Sahih al-Bukhari hadith:

Narrated Ibn `Abbas:
The last Verse (in the Qur'an) revealed to the Prophet was the Verse dealing with usury (i.e. Riba).
حَدَّثَنَا قَبِيصَةُ بْنُ عُقْبَةَ، حَدَّثَنَا سُفْيَانُ، عَنْ عَاصِمٍ، عَنِ الشَّعْبِيِّ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ آخِرُ آيَةٍ نَزَلَتْ عَلَى النَّبِيِّ صلى الله عليه وسلم آيَةُ الرِّبَا.
English reference: Vol. 6, Book 60, Hadith 67
Arabic reference: Book 65, Hadith 4586

Of course, this does not give the exact ayah.
Another common idea of the last verse revealed is the third ayah in surat Al-Ma'ida:

Prohibited to you are dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah, and [those animals] killed by strangling or by a violent blow or by a head-long fall or by the goring of horns, and those from which a wild animal has eaten, except what you [are able to] slaughter [before its death], and those which are sacrificed on stone altars, and [prohibited is] that you seek decision through divining arrows. That is grave disobedience. This day those who disbelieve have despaired of [defeating] your religion; so fear them not, but fear Me. This day I have perfected for you your religion and completed My favor upon you and have approved for you Islam as religion. But whoever is forced by severe hunger with no inclination to sin - then indeed, Allah is Forgiving and Merciful.

(emphasis mine)
So as you can see, there is no general consensus on the idea of the final verse. You can see several claims here, and a somewhat logical conclusion, although it is not a scholarly conclusion.
Answer: The above answer seems to answer the question pretty well. I'll just add one tradition which is mentioned in Tafsir Tabari:

وقـيـل: هذه الآية أيضاً آخر آية نزلت من القرآن
It is said: This verse too, is the last revealed verse in the Quran.

The mentioned verse is:

وَاتَّقُوا يَوْمًا تُرْجَعُونَ فِيهِ إِلَى اللَّهِ ۖ ثُمَّ تُوَفَّىٰ كُلُّ نَفْسٍ مَّا كَسَبَتْ وَهُمْ لَا يُظْلَمُونَ
And fear a Day when you will be returned to Allah . Then every soul will be compensated for what it earned, and they will not be treated unjustly.
2:281
Comment: I wonder if the answer you are pointing at still exists!


Can i use one laptop to charge another laptop by connecting the two together with a usb cable?

Question: My Toshiba laptop has a problem with the ac charging adapter.  The problem is with the computer and not the charging cord.  The geek squad told me that Toshiba laptops have had the same problem in the past.  I dont want to spend $400 dollars to fix it or buy a new one.  Please let me know if anyone knows a way to charge my computer.  Thank you and please give me good news!!
Comment: To answer your USB question, NO.
Comment: There was a question similar to this about charging via USB: http://superuser.com/questions/158398/charge-a-laptop-via-usb-power-500ma
Comment: There are many companies that do "DC jack repair" Google it.
Comment: @Moab: Or the power circuit is broken...
Answer: You might try a docking station. The docking station will charge the battery via a different connector (underneath the laptop). It will add some weight but could be less expensive than a repair/replacement.
Note: It is not only a loose power connector that can cause a charging failure. It can also be the power circuitry on the system board, which cannot usually be repaired except by replacing the board (a familiar problem with Dells; I don't know about Toshibas).
Having said that, I'd take it to an independent repair shop (definitely not geek squad), it may be a $50 fix if it is a loose connector.
Answer: What they were referring to is that the jack lifted off the board and needs to be soldered back on. Unfortunately if you ever want to charge it again, you'll need to have that repaired. HP and Compaq computers are also well known for this type of issue.
Answer: Over USB? No. The voltage is too low, it would take ages, and it simply won't work as you will blow up your laptop if you do find a way to do it.
Put your laptop battery in another laptop, charge it, put it back.
Only make sure that the battery's got the same voltage as the original battery of the laptop you place it in to charge. If ti doesn't fit, don't force it, better not take the risk to also screw up the other laptop.
Answer: In order to get charging working again you could as well just replace the power connector instead. Unless your power circuit is broke, in which case the USB charging isn't going work either...


Is triple check possible?

Question: In my logic, triple check not possible. Because I assume there is a move with two pieces at once needed. The only move I know is castling. The King can not give a check.
So is triple check impossible?
Comment: Suppose an illegal move is played which goes unnoticed by the opposite player. If the kings lands on a place where there is already a check, followed by a discovered double check results in a triple check!
Answer: Triple check is impossible, unless you want to count an x-ray attack as the third check.  A queen and rook attacking on the same file is normally thought to be one check.
Answer: To look at this systematically, let's say white is attempting to triple-check black.
At the start of white's move, black's king is not in check. So we have to go from zero checks to three checks.
When a piece moves:

the previous square it occupied becomes vacant (possibly creating a discovered check)
the target square becomes occupied (possibly creating a check from this new position).

These discoveries are possible:

Pawn, knight or king moves: discovery by bishop, rook or queen.
Bishop moves: discovery by rook or queen.
Rook moves: discovery by bishop or queen.

That only leads to two checks. (One unoccupied square can't cause two discovered checks because there is only one rank/column/diagonal between the king and that square).
What other options exist? Do any of the special-case moves support a third check?
En passant
This causes two squares to become vacant – the square that our pawn moved from, and the square that contained the enemy pawn. So two discoveries are theoretically possible. Could this work?
For a triple check, the king would have to be in the same file as the attacking pawn's starting position (to allow for discovery by a rook or queen), and on the 7th rank (to allow for check by the pawn as it reaches the 6th rank).
For example, if white plays gxf6, black's king must be on g7. We have a position like this:
<code>8/6k1/8/5pP1/4B1Q1/8/8/5K2 w - - 0 1
</code>
When the pawn captures, it opens up a discovered check along the g file. You can see that the removal of the black pawn cannot create a discovered check, as it is positioned a knight's move from the king, neither on a file, rank or diagonal.
Alternatively, if the king was at g6, then the en passant move would create two discovered checks: the queen and the bishop. But it would not also be checked by the pawn.
So, en passant can achieve:

two discovered checks; or
one discovered check, plus one regular check by the pawn;
but not two discovered checks plus a regular check by the pawn

Castling
Castling causes two pieces to move at once, which sounds promising. But one of those pieces is a king, which can never give check, so it doesn't help. And since the rook starts from A1 or H1, it can never give a discovered check in the process, either.
So, at best, castling yields one check.
Promotion
Pawn promotion sounds superficially interesting, but it's essentially like a normal move, that happens to start like a pawn and end like a queen or similar: a square is vacated, a square is occupied. Two checks are possible.
Double pawn move
The ability of a pawn to move two squares doesn't help: it's still vacating one square and occupying one other.
Conclusion
No, there is no way that three checks can be delivered with a single move in normal chess.
Answer: Triple check is possible in xiangqi, aka chinese chess. There is even the possibility for quadruple check.

Unique to xiangqi is a triple check, which arises in three combinations. In the first case of a cannon, a chariot or soldier, and a horse, the horse moves to give check, uncovering a double check from the chariot and the cannon. In the second, rarer case of a chariot or soldier and two horses, the chariot moves to give check, uncovering a double check from the two horses. In the third case of two cannons and two horses, one cannon may uncover a double check from the horses and act as a screen for the other cannon. Quadruple check is also possible, arising with two horses, a chariot, and a cannon. Triple and quadruple check cannot be blocked.

Source: wikipedia
Answer: Triple check is possible in the chess variant known as Cylinder Chess. In this position, 1.Ra8 discovers check from the queen and bishop, so it's triple or maybe quadruple check, depending on whether you count one or two checks from the rook, which is attacking the black king from two directions.
<code>[FEN "4k3/8/8/8/R3K3/8/8/3Q1B2 w - - 0 1"]

1. Ra8+
</code>
Answer: No.
Even if you could like take a pawn en passant and open up two lanes in 1 move, only 1 lane will be mathematically relevant to checking the king.
See, you can attack the king from a ton of directions, but all checking moves can mathematically only make 1 or 2 lanes/diagonal opened and thus relevant for delivering a check.
Chess notation for diagrams use + for a single check and ++ for a double check, but I've never seen a +++ character for a triple check. They simply don't exist.
Answer: The check itself defined as a player's king is under threat of capture by attacking piece(s) on next opponent's turn. According to standard chess rule, the pieces which can be counted as checking the king are pieces which able to move directly to the king's square.
These conditions counted as double check instead of triple check, assumed the pieces are attacking in one move:
1) Rook battery with queen/bishop/knight/pawn (second rook at the same file/rank not counted).
2) Queen-bishop battery with rook/knight/pawn (whoever supporting piece at the same diagonal not counted).
These conditions counted as single check instead of double:
1) Queen-rook battery (or two rook battery).
2) Queen-bishop battery.
Also, triple check is impossible in standard chess due to multiple checks must be executed in only one move, which allows maximum of 2 pieces capable to attack the opponent's king directly at the same time (attacking pieces are neither subject to be captured nor interposed by other opponent's pieces).
Answer: As others have pointed out, triple check is never legal in chess. It is, however, possible, even though no possible triple check is legal.
One context where this is relevant is in framing the rules of the game. The rules must be written so as to enable the reader who does not yet know what is legal, to learn this. In this answer, Brian Towers details a deficiency which at one time existed in FIDE's Laws of Chess which allowed triple check. (It's since been corrected.)
Another such context is in writing a program which, given a chess position, generates all legal moves from it. A candidate must be rejected as illegal if it leaves the turn player's king in check from at least one enemy unit. It is possible that there are three, viz if the turn player is in double check and moves a pinned unit.
Comment: Credit for the original research should, I think, go to R. Bosma who in 1993 noted the change in the FIDE Laws and realised the possible consequences. (See problem P1377135 at [PDB](https://pdb.dieschwalbe.de/search.jsp).) I acknowledge that you have written about this; so has Brian Towers, and so perhaps have others since 1993.
Answer: If you are to check a king, that can be caused by the figure you are to move or just by moving the same figure.
A figure that you are to move can check the king in only one way depending on the piece you are moving. The connection between a position where you are to move it and the position of the king is 1:1: they are on the same diagonal, row or column, or it is a knight attack.
A figure that you are to move can reveal a check, but then again the revealed figure is attacking the king in one way only. Since there is no knight or pawn chess that can be revealed all other checks are by revealed diagonal row or column, and that means it is the first and one figure on one specific diagonal row or column that can attack the king. So it can be only one figure that is attacking the king by revealing the attack.
On top of that, by the rule of chess, no figure can attack another figure in more than one way. An attack is simply: one position where a figure of opposite color could move next if the position were not already occupied.
So at worst a king can be attacked by revealed check and direct check at the same time after you move a figure. That is making it double check at most. Otherwise third check would have to be already there before you make your next move and that is not allowed or not even possible if it is a checkmate when the game is over.

Is triple check possible?


OS X Lion Connection to Business network?

Question: I have a client that wants to connect an OS X Lion macbook air to his business network remotely, and I was just wondering if anyone knows of a way to do this easily. Normally, I would set up a VPN server and allow for a connection in this way, but that is not a process I can recommend to "less techy" people. Is there an easier (while still secure) way to set up a business network connection remotely? Thanks beforehand.
Answer: I don't see a reason not to set up a VPN. You can add the VPN menu to the status bar and your client can simply select their VPN and enter a password when prompted. It's no more difficult than say, a TeamViewer connection setup. (In fact, VPN is arguably easier, since the system stores your username and merely prompts for a password. TeamVewer requires an ID and a password.)
I just began using VPN this week, and it's super easy. Really. To add VPN to the status bar:

Then, your client can simply click to connect, like so:

(VPN info blurred for security reasons.)
Comment: I fully agree with you. The VPN setup in Lion is quite easy.
Answer: You could try programs like Hamachi or even Teamviewer which now supports VPN. They both have easy to use installers for the less tech-savvy.
Otherwise if you have access to a Mac computer, you can create(export) a network preference file which can be double-clicked to automatically load the VPN settings.


gentle vs Forced push of motorcycle gear - wear and tear

Question: I am new to riding motorcycle. And I tend to use my legs a little forcibly while changing gears. A friend told me that this would cause the gearbox to wear out soon. He suggested me to do it gently such that it wouldn't make any sound. I am trying to do this right, but the sound always comes no matter how gently I press the gear. Is it true that this behavior can cause damage to gearbox or is it just a myth?
Comment: What I have found when riding motorcycles is that the gear-crunching is highly rider-dependent - some are able to shift more smoothly than others because their combination of throttle, clutch, engine revs and timing is a better one. Practice makes perfect, I guess.
Answer: I read a book called Engineer to Win by Carrol Smith. In the book he talked about the amount of stress any piece of metal can sustain before failure. He described how, for instance, a valve spring can handle many, many, many, revolutions of the camshaft as it bumps the valve train. It can deal with this over and over again as long as the lift of the camshaft doesn't exceed the designed limit of what the spring can handle. As long as the spring is operated within its design specs, it can virtually last forever. If the camshaft is changed out for one with a larger lift, which exceeds the design of the spring, the spring's life expectancy goes down dramatically. The larger the lift, the sooner the spring will fail.
How does this apply to what you are doing and experiencing? While banging the gears, as you are doing is probably not going to cause any noticeable damage right away, the more you do it, the sooner some part of the shifting mechanism or transmission is going to fail (either the lever, a gear, or whatever). It may be more fun to drive your bike by banging the gears, but do you need to do it to accomplish the gear shift? If not, you are causing undue wear upon the parts. Your banging the gears could cause stress risers to form, which, over time, will cause a part to fail. I would suggest your friend is spot on.
Answer: When you change gear you don't use your whole leg to change from one gear to another. You should be able to just use your foot and ankle without moving anything above your shin.
If you have to move the whole leg to change you should change the position of the gear leaver so it is closer to your foot.
To do this there is usually a bolt on the gear leaver that you can loosen off and then change the position of the leaver. Make sure the bolt it placed back on and fastened tightly.
In-regards to sound when changing gears this depends on the type of bike you ride. On my KLX 250 there is no issue with gear changes but guaranteed on a Harley Fatboy there will be a bigger clicking noise when changing into gear.
Easiest way to find out it to ask a dealer how much noise there should be between gear changes. They might tell you there should be nothing or that it is the nature of the beast
Answer: You will get better at shifting with time.
@willNz is correct, this is dependent on the brand of bike. Therefore, difficult to definitive answer.
Something you should check is to make sure the clutch is adjusted properly and the gearbox has the proper level of lube. Those two things can cause noisy shifting no matter how gentle you are. Cables stretch and parts wear, so it is amazing what a little adjustment can do.


Call blocking for iPhone?

Question: How do I block unwanted callers without jailbreaking?
Answer: A new feature of iOS 7 is call blocking and it allows the device to block calls apart from the previous solutions that involved jailbreaking or having the carrier block calls for you.
Go to recent calls within the phone app. Tap on the "i" to the far right of the number you wish to block. On this info page, scroll down. At the bottom of the page, tap "Block this Caller". Confirm on the warning message.
From the settings app, use iMessage and FaceTime preferences to manage the block list.
This list blocks calls, messages and FaceTime calls (audio and video) from that contact. Combined with a blocked contact as Loïc Wolff has proposed, you have a neat solution for dispatching unwanted calls on an ongoing basis.
Answer: Before iOS 7, the only way to block callers is to create a "Don't Answer" contact and assign the numbers you want blocked to it.
That way, you'll know not to answer when those people call. You can also assign the contact a "silent" ringtone.
Comment: Then create a ringtone that is silent and assign that to the specific contact.
Answer: If the number is still in your "recent calls" list, simply click on the circled "i" on the right of the number.  Scroll down to "Block this Caller" and then activate it  That simple.
Answer: In iOS 7 caller blocking is supported by the OS. Unless I'm missing something here the number you want to block needs to be in your contact list. So to block a new number you still need to add a contact first which seems a bit backwards.

Call blocking for iPhone?


Damaged carbon fibre wheels

Question: Can anybody tell me if you can repair a Wolber Carima carbon fibre wheel that has a chip on the rim?
Comment: It might, or might not, depend on the exact nature of the chip. Can you upload some photos?
Comment: You as a home repairer probably can't repair carbon fibre properly.  Check with Wobler about repairs that will be up to standard and will not void any warranty.
Comment: @Criggie - I suspect the warranty is already voided.
Comment: @ArgentiApparatus There does come a point where it's easy to tell, though:  if you see exposed or broken/cut carbon fibers, the wheel is done.
Comment: If the chip is not structurally significant, and just needs filling in then yes probably. The trick of course is knowing if it's structurally significant. The only way to find out is going to a professional CFC repair service.
Comment: You could add a photo to this question - that may help us give a more definite answer.  Otherwise the question's answers could be opinion or err on the side of caution.
Answer: Wheels are considered being too critical for riding safety to be repaired in case of carbon failure. A professional carbon-repair shop is unlikely to accept carbon wheels, cranks, handlebars, seatposts for repair.
A couple of quotes found on the web to back up my statement.

From https://calfeedesign.com/carbon-repair-faq/:

What do you not repair?
Frequently rejected repairs include: aluminum-to-carbon bonding, carbon handlebars, forks, seat posts/integrated seat posts, stems, damage to carbon wheels, and metal frames.

From http://ruckuscomp.com/getarepair : only frame parts can be specified, not wheels.
From https://www.donsbikeshop.com/about/carbon-fiber-frame-repair-pg289.htm

We don't repair wheels (even though the replacement cost is higher than the repair) because the forces exerted on the rim and the need to get the wheel balanced perfectly preclude a carbon fiber repair.

From http://joescarbonrepair.com/ says:

What do you not repair?
Frequently rejected repair requests are ones that involve aluminum-to-carbon bonding, carbon handlebars, forks, and damage involving the braking surface of carbon wheels.

However, https://www.applemanbicycles.com/repair/ says:

Carbon Repair Capabilities
  I can fix a wide variety of carbon fiber damage to your frame. The most common repairs are: ...
Disc Wheels (aero)

Damaged carbon fibre wheels


Is it against rules to add 2 tags one of which is a subset of the other

Question: My question (link here) originally had a htc tag. Then another user edited it to remove htc and added htc-desire-x instead. I felt both the tags are relevant and added htc back. But the user again edited my post to remove htc. Before getting into a toggle edit fight, I was wondering if it's against rules to have both the tags in a question?
Answer: The manufacturer tags like htc are more of a catch-all for when there isn't a more specific tag that applies (eg for obscure/unusual/new phone models), they're not needed if there's a more specific tag that applies, so aren't normally used, unless your problem is related to everything HTC related, which is rare.
Looking at the question, your problem could well be related to the HTC Sense custom interface, home screen and widgets that HTC add onto most of their phones now, so adding htc-sense tag in addition would make sense.
Answer: It is not against the rule, though putting the two is useless (if you do a "htc" search, all htc- tags will show up). I just think that if your problem concern only one particular device, it should have htc-device as tag but not htc. htc tag should be used for problems related to all HTC in general.
Comment: How is the person who keeps editing my tag sure that this is a [tag:htc-desire-x] specific problem? I have no idea either way
Comment: @user93353: I don't, but that's the device you mentioned. I strongly prefer _not_ putting device-specific tags on questions unless it is _clear_ that the issue is specific to that type of device. In hindsight I probably should have left it off. The question is clearly not about HTC in general, which is why I removed that tag.
Comment: @AlEverett How do you know it's not specific to htc-desire-x or just all htcs. When I googled for this issue - I found 4-5 people reporting it in different forums - all htc owners.


Slope definition of $e$

Question: A common definition of $e$ is given as
$$e = \lim_{n\rightarrow\infty}\left(1+\frac{1}{n}\right)^{n}$$
which can be proven to be equivalent to
$$e=\lim_{h\rightarrow 0}\ \left(1+h\right)^{\frac{1}{h}}$$
The most practical use of $e$ in elementary calculus is however given as
$$1=\lim_{h\rightarrow 0}\frac{e^h - 1}{h}$$
which is used as a statement the slope of $e^x$ at $x=0$ is $1$ allowing one to prove that $\frac{d}{dx}e^x=e^x$. It appears trivial to prove that the two limits given above are equivalent, but I cannot seem to make any progress without making some illegal limit operations. I suspect the problem is deeper than it appears (I suspect the trouble is that although we have defined $e$, we have not actually said anything about what $e^x$ is). How does one rigorously proceed from the given definition of $e$ to the slope limit?
Comment: But you're familiar with $$e^x=\lim\limits_{h\to\infty}\left(1+\frac{x}{h}\right)^h$$ aren't you?
Comment: @J.M. Yes I am. Admittedly I was taking a shot in the dark about what the actual difficulty of the problem is. Does this help in anyway for actually proving the equivalence?
Comment: I would go with using the binomial expansion, you see...
Answer: I'm not sure if you have multiple questions here but I'll try to answer all of them.
For deriving:
$$1=\lim_{h\rightarrow 0}\frac{e^h - 1}{h}$$
We start with the definition of a derivative:
$$f'(x)=\lim_{h \rightarrow 0} \frac{f(x+h)-f(x)}{h}$$
If we let $f(x)=a^{x}$, where $a \in \mathbb{R}$ then,
$$f'(x) = \lim_{h \rightarrow 0} \frac{a^{x+h} - a^{x}}{h}$$
$$f'(x) =\lim_{h \rightarrow 0} \frac{a^{x}(a^{h} - 1)}{h}$$
$$f'(x) =a^{x} \left( \lim_{h \rightarrow 0} \frac{a^{h} - 1}{h} \right)$$
If we let $a=e$, since $e \in \mathbb{R}$ we have that
$$f'(x) = e^{x} \left( \lim_{h \rightarrow 0} \frac{e^{h} -1}{h} \right)$$
Using l'hopital's rule and that $e^{h}$ is continuous at $h=0$ we can say that,
$$f'(x)= e^{x} \ln(e)$$
So, if we evaluate it at $x=0$ we have,
$$f'(0)=e^{0}=1$$
So that is how you obtain it one way.
Another way would go as follows:
Let $f(x)=\ln(x)$, then $f'(x) = \frac{1}{x}$, so $f'(1)=1$ and then we say,
$$1= \lim_{h \rightarrow 0} \frac{f(1+h) - f(1)}{h}$$
Because I like x's
$$1 = \lim_{x \rightarrow 0} \frac{f(1+x) - f(1)}{x}$$
$$1 = \lim_{x \rightarrow 0} \frac{\ln(1+x) - \ln(1)}{x}$$
$$1 = \lim_{x \rightarrow 0} \frac{1}{x} \ln(1+x)$$
$$1 = \lim_{x \rightarrow 0} \ln(1+x)^{\frac{1}{x}}$$
Raise both sides by $e$ and we get,
$$e^{1} = e^\left({\lim_{x \rightarrow 0} \ln(1+x)^{\frac{1}{x}}}\right)$$
$$e = \lim_{x \rightarrow 0} \text{ }e^\left({\ln(1+x)^{\frac{1}{x}}}\right)$$
$$e = \lim_{x \rightarrow 0} (1+x)^{\frac{1}{x}}$$
And there you have your second formulation. For the first one, just let $x = \frac{1}{n}$ and you receive,
$$e = \lim_{n \rightarrow \infty} \left(1 + \frac{1}{n} \right)^{n}$$
Hopefully that helps! Let me know if I made a mistake somewhere.
Comment: I appreciate the answer. However I am primarily interested in how the limit in question in obtained from the limit definition of $e$. Nevertheless your response is quite informative so I have given it +1. One question: How did you go from $f'(x) = e^x\left(\lim_{h\rightarrow 0}\frac{e^h - 1}{h}\right)$ to $f'(x) = e^x \ln(e)$?
Comment: For that simplification click "show steps" here: http://www.wolframalpha.com/input/?i=lim+h-%3E0+%28e%5Eh+-1%29%2Fh
As for how you obtain the last limit definition for e from the first one, take a look at the answer given by N.S., although he didn't exactly give a full explanation.
Comment: The method given requires the knowledge that $\frac{d}{dx}e^x = e^x$. Doesn't that make the limit rather trivial? It also seems too circular for my liking.
Comment: Where does it circular? You start with the fact that $\frac{d}{dx} \ln(x) = \frac{1}{x}$ and from there you derive the definition of e.
Answer: It is easy to go from the first limit to the second and back by using the substitution
$$z=\ln(1+h) \,,$$
Note that this is equivalent to $h= e^{z}-1$.
and the continuity of the $\ln()$.
$$e=\lim_{h\rightarrow 0}\ \left(1+h\right)^{\frac{1}{h}} \Leftrightarrow $$
$$1=\lim_{h\rightarrow 0}\ {\frac{\ln \left(1+h\right)}{h}} \Leftrightarrow$$
$$1=\lim_{z\rightarrow 0}\ {\frac{z}{e^z-1}} $$
Writing down a formal proof is easy now, you just have to be carefull filling it the details. You need to use the continuity of the logarithm function, the fact that $z=\ln(1+h)$ is a bijection from a  neighborhood of zero to a neighborhood of zero; and most importantly that for each of the two implications $e$ and hence $\ln$ are defined in a different way. Thus, you cannot really work with if and only if, because then $\ln$ makes no sense. But you can do each implication separately easely...

Slope definition of $e$


Temperature of the Sun's rays

Question: What is the temperature of the light that leaves the Sun towards the Earth and does it cool down during it's journey here ? If it doesn't cool down then how come it isn't frying the Earth ? Is it our atmosphere that is preventing it from doing so or does it cool down during it's trip here in space ?
Comment: The Sun makes black body radiation at 5800 K, but it's far away, so we don't fry. If we were closer, like Mercury, we would fry. If we were further away, like Neptune, we would freeze. So distance is also important. The closer you are, the greater the density of radiation; the further away, the lesser the density. What's actually important is not the black-body energy profile of the radiation, but its density - the amount of energy per square meter per second. We are just in the right spot for the density to be balmy and nice.
Comment: Somewhat related, informative and funny: https://what-if.xkcd.com/115/
Comment: @KeithThompson The photons have an energy distribution, if it is thermal distribution, it can be associated by a temperate. In the case of the Sun, it is 5870K. Even if they have no thermal distribution, an equilibrial temperature can associated by a photon field (if you put an item into the field, until which temperature does it heat/cool). This temperature is $\approx$ 260K on the orbit of the Earth.
Comment: @peterh-ReinstateMonica That's odd. I see your comment flagging me, but I don't see the comment you replied to. Was an old comment of mine deleted? (Not complaining; it's likely that I wrongly said that light doesn't have a temperature, but I don't remember it.)
Answer: The Sun's radiation spectrum is close to thermal at $T_\odot = 5778\,\mathrm{K}$. That means that that power output, given by the Stefan–Boltzmann law, is around $L = \sigma A T^4$, where $\sigma = 5.6704\times 10^{-8} \,{\mathrm{W}}/{\mathrm{m}^2\mathrm{K}^4}$ is the Stefan–Boltzmann constant and $A$ is its surface area:
$$L_\odot = \sigma(4\pi R_\odot^2)T_\odot^4 = 3.85\times10^{26}\,\mathrm{W}\text{.}$$
However, at the Earth's orbital radius $r = 1\,\mathrm{AU}$, this radiation is spread across a surface area of $4\pi r^2$, so the power incident on an Earth-sized sphere would be just
$$P = L_\odot\frac{\pi R_\oplus^2}{4\pi r^2}\text{,}$$
so approximating the Earth as a spherical blackbody, the equilibrium temperature is determined by its own thermal radiation balanced by this incident radiation:
$$\sigma(4\pi R_\oplus^2)T^4 = P\text{,}$$
which gives a surface temperature of
$$T =  T_\odot\sqrt{\frac{R_\odot}{2 r}} = 279\,\mathrm{K}\text{.}$$
Therefore, no special mechanisms are necessary to prevent the Earth from frying.
In reality, the Earth is not a blackbody because of its albedo and atmosphere, but its actual global temperature is not too far off from this estimate. The average surface temperature is close to $288\,\mathrm{K}$. Earth's atmosphere actually raises the average temperature, not lowers it.
Answer: Yes, you *can *assign a temperature to the radiation from the Sun. It is approximately a blackbody radiation field with a temperature of 5800 Kelvin. But no, it doesn't "cool" on the way to the Earth.
The radiation field is still a blackbody radiation field with a temperature of 5800K when it reaches the Earth, but its intensity (or power per unit area) has decreased from $6.4 \times 10^{7}\ Wm^{-2}$ at the surface (photosphere) of the Sun, to about $1.4 \times 10^3\ Wm^{-2}$, when it reaches the Earth.
It is this latter figure that is important in terms of how much the Earth is heated, not the temperature of the radiation field, because it determines how much energy per second is fed into the Earth's biosphere. An analogy would be an electric bar heater. The element will be emitting radiation at a temperature of 1000 C, but you don't burst into flames if you sit more than a metre away from it, because the power is distributed over a larger area.
In the absence of an atmosphere, the Earth would achieve an equilibrium temperature, such that it radiated away as much energy as it absorbed. This equilibrium temperature is much lower than the temperature of the Sun's surface because the power per unit area incident on the Earth is much less than the power per unit area emitted at the Sun's surface. The calculation, which I won't bore you with can be found here.
$$ T = T_{\odot}(1-a)^{1/4}(R_{\odot}/2D)^{1/2},$$
where $T_{\odot}$ is the temperature of the Sun, $R_{\odot}$ is the radius of the Sun and $D$ is the distance between the Earth and the Sun. $a$ is the "albedo" - the fraction of the Sun's light that is reflected back into space.
Putting numbers - $a=0.3$, $L_{\odot}=3.8\times10^{26}\ W$, $R_{\odot}=7\times10^{8}\ m$, $D=1.5\times 10^{11}\ m$; we find $T= 256 K$ or $-16\ C$. Of course the presence of an atmosphere warms us over this simple calculation by some tens of degrees.
Answer: An attempt to clarify/answer both this question and your
Heat from other Stars
Temperature is a property of matter, not of light. As others have
noted, you can assign a temperature to light, but I think that just
confuses the issue.
It's true the (mostly hydrogen and helium) atoms at the Sun's surface
are about 10,000F.
However, these atoms don't fly through space and then strike
Earth. Even with their high temperature, most of them can't escape the
Sun's gravity and remain on the Sun. The few that do escape form the
"solar wind", which has virtually no effect on the Earth's
temperature.
What travels though space is electromagnetic radiation (light), which
is measured by intensity and frequency. Light is not a physical
object, and doesn't have a temperature in the traditional sense of the
word.
Comment: I can just ignore the use of Farenheit, but there *is* a real physical difference between how radiation fields at high temperatures behave/interact with matter compared with radiation fields at lower temperature but with exactly the same power per unit area. These differences are not greatly relevant to this question, other than that a hotter radiation field (peaking in the UV) would not penetrate the Earth's atmosphere. But it is confusing and incorrect that both you and @KeithThompson have said that light does not have a temperature - it frequently does.
Comment: For a stark limiting case, see [photon gas](https://en.wikipedia.org/wiki/Photon_gas). That's not the situation here, but it illustrates quite plainly the danger of absolute matter/light distinctions on this issue.

Temperature of the Sun's rays


In the quest "a night to remember" Sam attacks me?

Question: When I am at the end of the end of the quest "A night to remember" in the grove that Sam is in, he won't talk to me he just attacks me and I don't know how to fix it.
Answer: This is listed as a known bug with this particular quest on the UESP wiki.  The suggested solution is to reload an old save, unfortunately.  You can try yielding (sheathing your weapon if you have one out, or unsheathing and then resheathing if you don't).  If you're on a console (Xbox 360 or PS3), these are likely your only options.
If you're on the PC, you could try using the developer's console.  I highly recommend that you backup your save before you start messing around in there, as you may create game-breaking situations.
Once you've made your backup, open the developer's console, click Sam, and then use the command:

setav aggression 0

To attempt to reset the aggression variable on this NPC.
Alternatively, you could try:

player.placeatme 0002E1F3

Which will cause the NPC which ends this quest to be moved to your location.  It's possible that if you're in the right spot this will end the quest and get you back into the real world.
If you've given up hope of wrapping up this quest, you can abandon the grove and head back to Skyrim with:

coc whiterun

which will jump you back to Whiterun.
Answer: You may be feared as a vampire, and need to feed.
I had this same issue for a long time, until I realized after reloading that I had just hit the 'need to feed' level of vampirism, where everyone fears me and fights me. I fast traveled to a town, fed, came back, and Sam no longer fought me.


Turbo Debugger - output cpu pane to file

Question: I was asked for a special debugger which prints out the name of original calls used by author. I know the original exe was packed with Borland Turbo C (v.3) and the only debugger which output function calls is Turbo Debugger from '90 era. The author used function name like call gocheckdate, call gettimepassedfromlastsave, for example. Other debuggers list call sub_ or _loc but I don't need those kind of outputs. So, for short: how can I output the entire Cpu pannel (code) from Turbo Debugger to a file without the method to capture screen, copy/dump to log, because this is a long time consuming job. I just need to output in a step (well 2 or 3 steps) all cpu pane window (starting from top or program entry point and ending at the bottom of listing- that is, at the end of scrolling), not to copy,paste,dump only the portion of code displayed at a moment on screen. (MS-DOS 16 bit exe, btw). If there is another disassembler who can indeed presents the original procedure/function name used by original author and can save entire code (assembler) to file please let me know. I also am aware about IDA but due different output it will be a more consuming time job to identify function/procedure names in Turbo Debugger (from Borland) and rewrite/replace IDA output. And I am also aware IDA output is different from TD output.
Comment: I would imagine that Turbo Debugger only provides symbolic information if you have the associated TDS file. IDA can load those files as well via file > load file > tds file.
Answer: td.exe that's way back don't have it handy to do a trial
answer pertains to td32 but i remember similar option available in td too
i see a log of an old lode runner game LR.com in the folder with pane dumps
alt+v->l->alt+f10-> open log file default is <prog_name>.log->ok
enable logging yes
dump the pane to log file using
alt+e->d->page down
iirc td macros can record macros to repeat keystrokes or
autoit can be used to script findwindow() sendmessage()

alt+v opens view menu
l opens log window
alt+f10 opens speed menu in log window
browse or accept default log file name
alt+ e opens edit menu
d dumps cpu pane to log file
pagedown to view and dump the next page

macro to reduce keystrokes to one charecter
alt+o -> create macro -> assign key (i assign 'z')
alt+e -> d -> page down -> alt + hyphen to stop recording

just keep z pressed till all is dumped :)

compile the code below and dump N number of panes to previously opened log file (alt+v->L->alt+f10->browse->ok) using the above mentioned macro 'z'
#include <stdio.h>
#include <windows.h>
#pragma comment(lib , "user32.lib")
unsigned long numtopaste = 1;
BOOL CALLBACK EnumWindowsProc( HWND hWnd, LPARAM lParam )  {
    UNREFERENCED_PARAMETER(lParam);
    PCHAR Temp = (PCHAR) calloc(64,sizeof(char));
    if (Temp != NULL)    {
        GetClassName(hWnd, Temp, 64);
        if ( strcmp ( Temp , "ConsoleWindowClass" ) == 0 ) {
            PCHAR Wind = (PCHAR) calloc(64,sizeof(char));
            if (Wind != NULL) {
                GetWindowText(hWnd,Wind,64);
                if ((strstr(Wind,"TD32.EXE")) != NULL) {
                    printf("found TD32.EXE ConsoleWindowClass\nHandle = %p\n"
                        "Command Line =%s\n pasting %c Number of Times %d \n",
                        hWnd, Wind,'z',numtopaste );
     // blogs.msdn.com/b/bill copy to clipboard 'z' and paste to Console
                    for(ULONG i = 1; i < numtopaste ; i++) {
                        SendMessage(hWnd, WM_COMMAND, 0xfff1, 0);
                    }
                }
                free(Wind);
            }
        }
        free(Temp);
    }
    return TRUE;
}
int main(int argc , char * argv[]) {
    if(argc !=2) { printf ("usage %s NUM",argv[0]); return 0;}
    numtopaste = strtoul(argv[1],NULL,10);
    EnumWindows(EnumWindowsProc,NULL);
    return 0;
}

Comment: I know this kind of save /dump one by one screen to log. Imagine this: my code pane has over 1000000 lines (just an example). It is time consuming to press f10, [e], [d], page down. Thanks anyway for the answer, I will vote up for the details.
Comment: i added a macro sequence try that you don't. have to press  several keys and pressing that single key can also be automated
Comment: Tried macro sequence it is better anyway than previous. :D Thanks.
Comment: compile the edited code to foo.exe and run it like foo 10 will dump 10 panes to log file  (code assumes you have setup z macro )


How can I improve my shot?

Question: What is the correct way to shoot a football? Please suggest me some drills for improving my shooting power?
Comment: possible (at least partial) duplicate: http://sports.stackexchange.com/questions/2442/what-factors-does-the-shot-power-depend-on-and-how-can-it-be-improved?lq=1
Answer: There is no one-true way to shoot in football, the only correct way is the way that works (i.e. the way you can score the most with).
That being said shots can be classified with the part of the foot that comes in contact with the ball, as SahuKahn has mentioned in his answer. I'll give more details:

Inner side of the boot: the most classic shot with the inner side of your boot. Here's a video explaining this type of shot. Pros: typically best accuracy, most control on the ball thus best chance to "place" the ball. This type of shot is also easier to fake and continue with a dribble.
"Knuckle" shot: name is pretty self explanatory really. Here's a long video showing examples and some explanation as to how to shoot like that. The advantage is that the ball path is really difficult for the goalkeeper to judge, and the drawback is that it's hard to "get it right". Usually you need a good and controlled run up to the ball, thus this type of shot harder to pull off in the heat of the game.
I have personally tried it out and I can see a definite improvement of my shot even tho I am not quite there yet..
Lace shot: This would be the footballs equivalent of a "smash". I would call it a typical, old-school English shot with Steven Gerrard and Frank Lampard being two kings of this type of shot. Here's a video comparing those two players (the first 2 mins is relatively irrelevant fan stuff). Pros; full power on the shot, practically the entire motion of the leg is transferred to the ball. Cons; hard to control the accuracy, also ball path is usually pretty much straight
Outside shot: This is actually pretty much the opposite of #1. Outside of the boot, very little control (usually) and you get the reverse curve on the ball. Good example of such shot would be to look at Quaresma, here's a small collection of goals he scored.
This type of shot is unpredictable and hard to save for the goalie and it typically generates a counter-intuitive path. However it's also extremely hard to get it effective and outside of the boot is typically not the best part of the foot for control. For instance I was told on multiple occasions to keep my outside-foot dribbles/shots/passes to an absolute minimum.
Chip: You use the front part of your boot and go under the ball, to lift the ball quickly. This type of shot is used to "chip" the ball over the goalkeeper, either because the goalkeeper is far off the goal (in comparison to where the ball is) or that goalkeeper is charging to sweep the ball. Here are some examples.

Besides these you can of course shoot with your toes, or heel etc, but that's not that much different than shooting with your knee or shin; the ball hits you somewhere and if you are lucky and get a "clean" hit then the ball bounces back towards the goal.
I would not recommend relying on a toe-shot (even though we have seen several scored this world cup like Oscar's goal vs Croatia) as it's weak and typically very straight ball path.
As for how to improve: practice makes perfect. Look for drills, take shots against a wall, against targets, ask tips and pointers from friends. I typically play with the ball before and after the games, and aim at the goal, the posts, the crossbar, any signs or lampposts, even friends. Even that counts as practice... The more shots you take, the better your foot and your brain understands the ball paths, and amount of power you need to put in to get the shot right.
Comment: Use of the outside of your foot is a skill like any other, so with practice you can become proficient. I would never tell someone not to use a skill because it's less commonly used because less people practice it. It's a different skill that has different benefits.
Comment: @DannyBland I agree that outside shot/cross/pass has a role to play in the game, and a valuable asset to have for any player. But it's perhaps not the best place to start improving/practising, that's all I am saying :)
Comment: I agree with that! If you can't consistently control shots with the inside of your foot, it may be best to leave practicing outside of the foot until you can!
Answer: There are number of ways to shoot.

Sidefoot shot  - In this shot, you hit the ball with the side of your foot. This gives you  greater accuracy and you will have more control over where the ball should go.
Instep (laces) shot -  This is a shot where you hit the ball with your instep (the area where your laces are). This gives you more power than a sidefoot shot, if followed through nicely. Also this can cover a greater distance.
Toe poke - This is the least preferred shot. That's because you don't get much accuracy with this, and the ball just goes straight ahead. This can be used when you are very near to goal, and are rushed to take a shot. Basically to "Stab the ball home".
Outside of your foot - This is basically the reverse of side foot, and in this you hit the ball with the outside of your foot. This is useful in cases when you need to give the ball the reverse spin. It doesn't generate a lot of power though.

To improve your shooting power, have a look at this answer.
Answer: As the other answers state, there are a few different types of shot, with each type requiring different things. People have described the shot types but not how to improve or what is required. It is true that everyone is different so what works for one may not exactly work for another but it is still a good base.

Inside of the boot - what you're looking for is to either strike the ball completely with your instep, aim for the ball to strike your foot further up than your heel, but further down than your toes. You can also turn you foot towards the ball when doing this, adding spin and swerve onto the ball. A key part of any shot, this included, is about foot and body placement. You should open your hips slightly, place your left foot (or right if you are left-footed) between 8-16 inches to the the side of the ball. The distance depends on you and what feels more comfortable and allows for more accuracy and power. Also, leaning back while shooting will mean your foot is coming up to meet the ball, and thus you will strike the ball high, whereas if you lean over the ball slightly, the ball should stay low. The knuckleball technique from @posdef's answer is a variation on the the inside of the boot where the foot is used to add a lot of spin and hit in a certain way to add swerve and dip on the ball. The reasons for this can be found by studying fluid mechanics, as the air passes across the ball.
Laces shot - this shot provides the most power but there is less control. You are looking for your foot to be placed slightly more outside the ball as you swing you foot through. You can add spin by hitting it at varying angles, but it is more difficult to do so than with the inside of the boot. It is crucial to keep your body over the ball in this shot, due to the added power and less spin. If not, it will invariably end up flying up and over the goal.
Outside of the boot - this shot is the most difficult to learn, as it is counter intuitive to what most people have learned growing up. The benefits are that you can now curve the ball both directions, catching out oppositions that didn't expect it. I like to use the outside of my boot if I am shooting right-footed from the right side of goal, aiming for the bottom left corner, as it will hopefully curve round the goalies reach and into the corner. Inside the boot would send the trajectory in to the goalie and then away giving them more chance to reach it.
Chip shot - this shot is when you think you can get the ball over the defenders/goalie and down into the goal. You use the front of your foot for this usually, although you can use any technique if you practice it enough! It is also less important to keep body over ball, indeed it is sometimes helpful to lean back slightly when chipping.
Back heel - this shot requires knowledge of the where the ball is, where it will be when your foot reaches it and where you want to send the ball. This is more about the awareness of the ball, and you swing whichever leg you are shooting with back towards the ball, hoping to hit it with the centre of your heel to get the most power and accuracy.
Toe poke - are the least commonly used shot and can also cause you damage if you strike it incorrectly. Toe-pokes are only to be used when stretching for a ball you otherwise wouldn't be able to strike in my opinion. Other than that, there is always a better option, for placement use inside of foot, for power use laces.

It is important to remember about body position when shooting and foot placement. Try to focus on these as well as the actual striking of the ball when practicing and you should definitely see improvements in your shot!
Comment: +1 for supporting foot placement. Without a a good support the shot will likely be weak and less accurate.

How can I improve my shot?


How can a suspended user ask a question?

Question: One of today's questions looks like it's been asked by a suspended user -- the user has 1 rep point and the account profile says the account is temporarily suspended. How is that possible?
Answer: A suspended account cannot post new questions. What happened was that the user created another account to evade suspension. When such cases are discovered, the offending accounts are often merged into the master account that's still under suspension.
The post ownership is transfered to the master account during the merge and thus the post looks as if it were made by a suspended account.
Comment: @PreferenceBean only until December 2017!
Comment: Makes perfect sense.  Thanks for posting the question and answer and educating us.
Comment: @Carson It's a little ... complicated. There are multiple IP addresses involved and banning each one individually is not feasible. We're currently taking a "moderate the questions as they come and merge users when we find them" approach.
Comment: Is this *really* working? [Goma](http://programmers.stackexchange.com/users/26782/goma) has allegedly been suspended for months, yet he has posted 20 questions in the last couple of weeks - 19 of which have been closed for being off-topic, non-constructive, duplicates, etc. Is he really creating new accounts regularly to evade his suspension? If so, is there any further activity that can be taken? IP block?
Comment: @Carson63000: It's amusing to me that Goma is _still_ suspended ^_^


Under Sharia law, if a muslim became an apostate but then reverted back becoming a muslim again, would the apostate still be sentenced to death?

Question: I'm just wondering whether if you still are or not, I think that would so unfair if he/she is still be killed.
Answer: No the sentence of death would not be carried out if this is the case.  Under the Shariah, if a person openly goes out of Islam then the punishment for this crime is death, but before the carrying out of the sentence, three days is taken to discuss/talk/convince him to repent before the punishment is applied, if he/she refuses the punishment would be carried out, if he/she repents then the punishment would not be carried out and may Allah accept their repentance.
Comment: What if a Muslim goes apostate for years (which is far more than 3 days), does not get punished, and then (after years) he decides to become a Muslim again?
Comment: @user4150 Well that's the problem with sentencing a person who simply apostates intellectually without causing the society any harm. The 3 days warning is not attributable to any saying of the Prophet (SAW). Is 3 days sufficient to make a person dispel all the doubts he had been harboring for years? The fact is so far one is alive, there's hope that he may return to the right path.
Answer: No. Under the Sharia law (al-Hadd or hudud) the person who became an apostate (riddah/murtad) must be warned for a period of times (there are alot of views on this period of time, some says 3 days, 3 months etc) to revert back to Islam.
After the period of time ends, if he still refuses to revert back to Islam, then he shall be sentenced to death.
Comment: Please provide evidences.
Answer: Say, "O disbelievers, I do not worship what you worship. Nor are you worshippers of what I worship. Nor will I be a worshipper of what you worship. Nor will you be worshippers of what I worship. For you is your religion, and for me is my religion." - Quran 109:1-6
Also see Quran 2:256 with a similar message that there is no compulsion in religion.
Point being, there is no death sentence either way because Quran itself states that religion is not compulsory. Sharia is derived from various sources, but as a Muslim you should stick to what Quran says.
Answer: "In light of the texts (Qur'an and prophetic traditions) and the way the Prophet behaved with the people who left Islam (like Hishâm and 'Ayyash) or who converted to Christianity (such as Ubaydallah ibn Jahsh), it should be stated that one who changes her/his religion should not be killed. In Islam, there can be no compulsion or coercion in matters of faith not only because it is explicitly forbidden in the Qur'an but also because free conscience and choice and willing submission are foundational to the first pillar (declaration of faith) and essential to the very definition of "Islam". Therefore, someone leaving Islam or converting to another religion must be free to do so and her/his choice must be respected." (Tariq Ramadan on Apostasy)
Source:http://www.youtube.com/watch?v=9CdxkF3q44E
Both Ibrahim al-Nakha'i  and Sufyan al-Thawri were of the view the apostate should be re-invited to Islam, but should never be condemned to death.
Source:  Chapter: Freedom of Religion in Mohammad Hashim Kamali's Freedom of Expression in Islam Islamic Text Society, 1997
Also I think you might find this link useful it's sites various various respected scholars showing that apostasy is not punishable under Sharia
http://apostasyandislam.blogspot.ca/
Answer: Sentence to death of a person who leaves Islam, is not valid after the time of Prophet Muhammad (PBUH). Since, the death sentence is not valid now, if a person comes back to Islam, then it is nothing more than a blessing of Allah on him.
Explanation
A prophet (rasool) is God's "hujjat" (ultimate proof) on this earth. He clarifies the God's message, to such a degree that there is no valid reason to deny him and his message. A time comes in prophet's struggle when his nation openly denies him. After that time, the prophet's nation is under God's wrath.  Thus, ONLY the believers are saved and every single person who is non-believer is killed. This is a proof of prophet's truthfulness and it is a "sunnah" of God that has manifested itself, time and again, ONLY during the presence of prophets.
It is usually done by a catastrophic natural disaster. Qur'an alludes to many such events of the prophets. The other way of God's wrath comes from the believers themselves. This only happens when the companions of the prophet are sufficient in number and also have a political governance.
In Prophet Muhammad (PBUH) case, the nation of the prophet in Makkah was under God's wrath when he emigrated to Madina. He got enough following and was able to make a small "state" in Madina. Thus God chose the second way to punish the non-believers.
Since the nation of Prophet Muhammad (PBUH) was already given a sentence to be punished to death, this became a precursor to the ruling that if a non-muslim ( of Prophet Muhammad's PBUH nation) tries to save himself by declaring Islam and then later denies, he is to be killed. Later on it was generalized for all time, while this rule is only specific to God's sunnah during the life of the prophet.
Thus death sentence of an apostate is not valid.


Can any one please tell me where I can find the latest python implementation of monero RingCT?

Question: Mininero is a python implementation of monero. But the git repository is three years old where the latest link does not have any content. Is there any other python implementation of monero where code for LSAG and ringCT is available?
Answer: I've implemented the Monero transaction code signing for the Trezor in python, the code is here:
https://github.com/ph4r05/monero-agent
And MLSAG in particular: https://github.com/ph4r05/monero-agent/blob/master/monero_glue/xmr/mlsag2.py
The python implementation also contains pure-python Bulletproofs implementation.
Comment: Thanks. In mlsag2.py, the parameter pk of the function gen_mlsag seems to be a matrix of Edpoints. Is it true? In particular, is there any test file calling gen_mlsag?
Comment: @trijia correct, `pubs` is the mixring matrix. I ported it mainly from the original C++ source so it should have similar interface.

It is called by transaction signer: `monero_glue/protocol/tsx_sign_builder.py`
There are tests for the whole transaction signing process in `monero_glue_test/test_agent_lite.py`
Comment: In `gen_mlsag`, `join` that is used in generating `m` is not working for `pk[0]` (a vector of Edpoints). It says that "expected str instance, EdPoint found".
Comment: `gen_mlsag` is old version of MLSAG, I've removed it now in the master. Better use `mlsag2.prove_rct_mg_simple` which is called by the `test_agent_lite.py`
Answer: Mininero has a python implementation of RingCT. I wouldn't rely on it being up-to-date with Monero's core implementation as if I recall correctly, it's purpose was originally a testbed of RingCT before it was implemented in Monero proper. Useful still for academic purposes nonetheless.


Who is kaal? What is kaal?

Question: Who is kaal? What is kaal? What does vedas say about this vedic god? Is he vedic god? Is kaal different from Yamadeva?
Comment: You can see my answer http://hinduism.stackexchange.com/a/9290/3500
Comment: Yama deva is Lord of Kaala( death). Shiva is lord of Kaala( Time).
Answer: As per Srimad Bhagavatham,

Kaalohi bhagavaan karta, satatam sutatam sukha-dukha yo ho;
naraanaam para tantraanaam janma punya papanu-yogitha-ha!

Time itself is Bhagavan, THE GOD. As per Vedam and Vedam recites Lord Srimann Narayana is Maha Kaaludu, Kaala purusha, Kaala Swarupa, Kaal Atmaka. HE himself is Maha Kaala.  He is Creator, Responsible person and director of Time. With the Times(Maha Kaala), Living entities or Living beings will experiences the Happiness or Sadness(Good Time or Bad Time) based on their previous birth/Janma Karmas(Punya or paapa).
The Bhagavan has given some duties or responsibilities and Powers for HIS Subordinate deities to perform and rule as HIS Order.
Among various deities Lord Yamadeva is one subordinate Deity of Lord Kaala Purusha.
Comment: Lord Vishnu is as equivalent as Lord Shiva. Both are one and the same.
Comment: Lord Vishnu is Kaal and Lord Shiva is known as Maha Kaal.
Comment: Yeah, I know that. It is just the same God who has taken different forms.
Comment: @ChinmaySarupria: what's difference between `Kaal ` and `Maha Kaal`?
Answer: In a philosophical sense, KAla ("kaal") is inclusive of but not limited to Time. When there is something or nothing in the universe, the KAla is always present. It's eternal God. Other things change with respect to it. Hence, because it gives the value of change (duration), it has to remain unchanged!
There are below references of the term KAla ("kaal") in Bhagavad Gita:

Eternal -- For those who intend to gauge it, it's infinity

[BG 10.30] — Among Daityas I am Prahlāda, among calculators
  I am KAla, among beasts I am the lion, and among birds I am Garuḍa.

Destroyer -- It destroys everything, hence changes everything; Here "destruction" should not be taken always into literal sense; e.g. present 1 second will be destroyed in 1 second

[BG 11:32] Sri BhagawAna told: I am the expanded KAla for the
  destruction of the loka(world); For hunting people here, I am
  activated;  Except you (PAndava), all the soldiers situated in the
  opposite sides will not exist.

"Kaal" with respect to various aspects of time, is described in Mokshadharma Parva:

The Rishis, measuring time, have named particular portions by particular names. Five and ten winks of the eye make what is called a Kashtha. Thirty Kashthas would make what is called a Kala. Thirty Kalas, with the tenth part of a Kala added, make what is known as a Muhurta. Thirty Muhurtas make up one day and night. Thirty days and nights are called a month, and twelve months are called a year. Persons conversant with mathematical science say that a year is made up of two ayanas (dependent on sun's motion), viz., the northern and the southern. The sun makes the day and the night for the world of man. The night is for the sleep of all living creatures, and the day is for the doing of action.

There is more to it, which is discussed with details in below answer:
What is the duration (Timeline) of the four "Yugas"?
Answer: Kaala is Time, represented by the Kaala Chakra, worshipped independently or Yama as a presiding deity. The text Yoga Vashishtha, a conversation between Maharishi Vashishtha and Shri Rama, has multiple references on Kaala providing beautiful insights:

• Time cannot be analyzed; for however much it is divided it survives
  indestructible. [1.23]
• There is another aspect of this time, the end of action
  (kritanta), according to the law of nature (niyati). [1.25.6-7]
• The world is like a potter's wheel: the wheel looks as if it stands
  still, though it revolves at a terrific speed. [1.27]
• Just as space does not have a fixed span, time does not have a fixed
  span either. Just as the world and its creation are mere appearances,
  a moment and an epoch are also imaginary. [3.20]
• Infinite consciousness held in itself the notion of a unit of time
  equal to one-millionth of the twinkling of an eye: and from this
  evolved the time- scale right upto an epoch consisting of several
  revolutions of the four ages, which is the life-span of one cosmic
  creation. Infinite conscious- ness itself is uninvolved in these, for
  it is devoid of rising and setting (which are essential to all
  time-scales), and it devoid of a beginning, middle and end. [3.61]

Reference used: http://arxiv.org/abs/physics/9903010

Who is kaal? What is kaal?


What is the best way to export animation from Adobe Animate for WEB?

Question: I'm not familiar with Adobe Animate. But I want to ask 2D artist to export animations from Adobe Animate to append to my HTML page. As for me the best way to append animations is SVG animations with CSS and avoid GIF because of its large size and raster-based. Are there possibilities to do that in Adobe Animate or could you recommend any external tool?
Answer: Not sure about "the best", since that's a very subjective judgement. However you can create HTML5 Canvas animations with Adobe Animate CC.  It's mentioned on the Adobe Animate help website: Create and publish HTML5 Canvas documents in Animate.
Here's a brief quote from the page, just in case the link above rots.

Canvas is a new element in HTML5, which provides APIs that allow you
  to dynamically generate and render graphics, charts, images, and
  animation. The presence of the Canvas API for HTML5, strengthens the
  HTML5 platform by providing two-dimensional drawing capabilities.
  These capabilities are supported on most modern operating systems and
  browsers.
Essentially, Canvas is a bitmap rendering engine, and the drawings are
  final and cannot be resized. Furthermore, objects drawn on Canvas are
  not part of the web page's DOM.
Within a web page, you can add Canvas elements using the  tag.
  These elements can then be enhanced using JavaScript to build
  interactivity.
Comment: This is the answer. CreateJS is the way to do it.


What are the best questions to ask a PI upon the first meeting to join some of his projects?

Question: I'm planning to see a professor today, in our department, he is the director of one of the labs there and a PI of a couple of projects. I knew that, he's looking for some student to join his project/s. I contacted him, he told that he's a couple of funding projects and make an appointment for me to see him. So, I'm thinking what are the best question that I may ask during this first meeting.
Comment: See [What are the 'right questions' to ask professors at a visit day for prospective graduate students?](http://academia.stackexchange.com/q/17192/) and [How to evaluate potential advisers on grounds other than their research/publications?](http://academia.stackexchange.com/q/158/). Then, find a way to talk to this professor's students, and see [What questions should one ask to the former/current students of a professor before deciding whether to do PhD under him/her?](http://academia.stackexchange.com/q/8507/).
Comment: Then that's the important thing to convey in your conversation.
Comment: I may not do PhD under him, for time being, it seems, I just want to work on these projects and get paid.
Answer: Ask the prof to tell you about his work. Then ask what expertise/skill set is most important to him among his lab team. Listen closely and then look for opportunities to describe how your skill set fits what he needs in his lab.
Answer: Ask:  What kind of questions is your research trying to answer?  Is that a question that the field itself has asked, industry, or personal interest?  My experience is in X and interests are X Y and Z.  Might I be able to assist you?  Where do you think an answer might take you?  Is there the possibility of sharing authorship?
You have to asked these relative to what experience, interests, and ideas you might have.  If the research is coming from industry, the approach to join would be quite different, than one from academic inquiry itself, for example.
In any event, my suggestions are not really a template for you to follow, but to prompt you to have a conversation trajectory in mind.
Answer: What is your management style?  What do you contribute to the research group?  How do you get funding?  How do you help your students succeed?  Can I meet your current students?  Where are your alumni now?


Should pages linked to in my nav and footer be included in my sitemap?

Question: I'm more of a back end developer and can't answer this question from my own research. When setting up the links in my sitemap, do I need to include the pages that I link to in my top navigation and footer? These links show up on all pages and will be crawled if/when any page on the site is crawled.
Answer: Links that will ordinarily be crawled when your site is crawled, like those in a top navigation or footer, don't necessarily need to be included in a sitemap. As specified by Google:

Sitemaps are a way to tell Google about pages on your site we might
  not otherwise discover...Creating and submitting a Sitemap helps make
  sure that Google knows about all the pages on your site, including
  URLs that may not be discoverable by Google's normal crawling process.

Just make sure they won't be blocked through some other means (like Disallowed in a robots.txt, hidden in complex JavaScript, blocked with a noindex meta tag on the page, or an X-Robots-Tag HTTP header, etc...).
Answer: If you are referring as sitemap to links that you put in your website to help the users to find your content easily, you can add those links as plain text if that helps to better recognize the structure of the site. If you are referring to those sitemaps that you send to Google, I personally don't care, because I make them with an automatic crawler: http://www.xml-sitemaps.com/


In a rear-ending traffic violation, is the ticket dropped if the other party does not show up but the officer does?

Question: I rear-ended someone and received a "failure to maintain safe distance" citation. I don't believe I'm at fault and am considering challenging it in court. I don't want to get an attorney or deal with any of that, so I'm partially counting on the other guy not showing up. At the scene of the accident, the officer told me that if the other guy does not show when subpoenaed that it would be "a no-go". Am I correct in interpreting this to mean that the ticket will be dropped?
Answer: Not necessarily. Your own statements and the statements of the officer would be legally sufficient to convict you.
Also, your statement that you don't believe you are at fault is strongly at odds with a widely held interpretation of the traffic laws (not stated in the formal language of these statutes). The prevailing interpretation of the traffic laws is that you are always at fault if you rear end someone because you failed to maintain a safe distance, pretty much as a matter of strict liability and regardless of the circumstances, because a safe distance is almost by definition a distance that it is possible for you to come to a full stop from if the care in front of you suddenly comes to a stop for any reason. The only situation I can imagine where there wouldn't be liability for rear ending someone would be if you were at rest behind them at a stop light and they actively backed up into you.
In practice, almost any judge and almost any jury, would convict you of failure to maintain a safe distance if you rear ended someone absent the most extraordinary of circumstances. I honestly don't know any lawyer or likely potential juror who wouldn't convict you under these circumstances with only the testimony of the police officer and your own testimony (which you would have to offer to have any shot at avoiding a conviction) to establish that you did indeed rear end someone.
Police are allowed to lie to suspects of crimes, and often simply do not have an accurate understanding of how the legal system works. So, you are not entitled to rely on a statement made by a police officer.
Of course, it is also certainly possible that his statement is consistent with local practice in your neighborhood traffic court. So, showing up to contest the charge might still make sense, and it wouldn't be uncommon to receive a plea bargain with fewer points against your license, just for showing up to court.
Comment: My brother was once driving in the right-most lane of a 4-lane city street and someone in the next lane over changed lanes directly in front of him under heavy braking to make a right turn into a parking lot.  My brother rear ended him because he had no time to react.  Fortunately there were other witnesses and the other driver was found at fault.
Comment: Another common situation is that a car is rear ended because they pull into traffic when there is not sufficient room (failure to yield).
Comment: @James Certainly there are very exceptional circumstances where the other driver could be at fault, but they are rare, and in the land of traffic laws unlike tort law, it wouldn't be unusual to cite both drivers rather than just one or the other. Both can be in violation of traffic laws even if one is more at fault than the other. Your second scenario might be such a case. Likewise "careless driving" can cover a multitude of marginal cases.
Answer: The "state" is the party that "presses charges" for a traffic violation (and in fact for all crimes).  For summary offenses it is sometimes the citing police officer who represents the state in court.  Therefore, the police officer can use his discretion to dismiss the charges before trial, or plea bargain with you for lesser charges.  Also, you can move the court for the charges to be dismissed if the officer (who is the plaintiff) misses the court hearing.
In the case of a rear-end collision, you might face a separate civil claim from the victim, or his insurer.  Again, if that goes to trial, and the plaintiff fails to show up, the court may be moved to dismiss the case.
Comment: Practice differs from state to state. Most states would have a junior attorney in the District Attorney's office handle prosecution of a traffic violation with the officer present merely as a witness. Only a minority of jurisdictions would allow the police officer himself to dismiss charges or plea bargain. But, it would still be true that it is the "state" that presses charges and would exercise discretion as to whether charges are dismissed or compromised.
Comment: @ohwilleke - I needed a reminder of how odd Pennsylvania is!  I just changed "usually" to "sometimes...."
Comment: @ohwilleke: Yes, it's similar in Germany. For minor violations (_Ordnungswidrigkeit_), police officers have discretion of whether to issue a citation or not, but once the citation has been issued, the rest is in the hands of the district attorney or the court.


How to inject a DLL without being detected?

Question: I understand that DLL injection can be used to modify games, perhaps for the purposes of writing a bot. Last time i injected a DLL, it was detected.
My injection method must have been detectable then, the question comes down to
how do i avoid getting detected? Please help me out, multiple ways to do this would be greatly appreciated
Answer:
how do i avoid getting detected

You can't know how to avoid getting detected if you don't know how the detection works. I'd recommend finding and reverse engineering the detection logic so that you can either disable it (patch it out) or better understand how to avoid detection.
That said, if you're looking for a generic alternative to "standard" DLL injection approaches, you may want to consider reflective DLL injection:

Description
Implementation

Note that reflective DLL injection is detectable as well, which again highlights the importance of knowing how the detection logic works for your scenario.
Answer: There are many forms of dll injection, the most common being to load code into the remote process that calls LoadLibrary in order to load the payload dll.  Some anticheats hook LoadLibrary in order to catch or prevent such methods.  To prevent this, you'd need to eliminate the call to LoadLibrary.  This means you'd need to imitate the windows PE loader and prepare the dll yourself to be executed.  This method is called "manual mapping", and you can find an example of code that achieves it here.  The bare minimum of steps you need to perform is mapping base relocations and fixing imports, and my brief scanning of this code shows that it should achieve this.


Does the time of day of sugar consumption matter?

Question: If a person consumed 4-5 pieces of fruit each morning before working out in the afternoon, would they see different results (weight gain or anything else) than eating those same 4-5 pieces of fruit in the evening and waiting until the next afternoon to workout?
Answer: If you eat a substantial meal before exercising, you will burn slightly more calories than if you ate the same meal after exercising. The reason for this is that by eating before, you then have to tote around that much more mass, which requires slightly more calories to perform the same exact task. This is one of the reasons why people on a diet eventually reach some stable weight; eventually the fewer calories they are eating reaches the amount they need to fuel their activity at their reduced weight (mass). Put another way, lighter people need fewer calories just to go about their day-to-day activities than more massive individuals.Will this make a real difference over the course of, say, a year? I very much doubt it; the difference would be completely overwhelmed by variations in daily activity and food consumption. That being said, if two individuals were tracked over the course of a year with their activity and food consumption completely regulated, the one eating before exercise would lose slightly more weight than the one eating afterward.There are charts showing calorie requirements, weight, and physical activity here. One could probably calculate the difference, but I'm too lazy (and pressed for time) to actually do so. I guess my final point is that the difference would be largely academic.
Answer: There does not seem to be a wealth of scientific research relating to the effects of meal timing on weight gain or other health metrics. The common conception is that a calorie is a calorie and there shouldn't be a difference in weight gain if you just change meal time and all other variables are left equal.
As for meal time in relation to exercise, there also does not seem to be a consensus about whether it is better to eat before exercise or not. The argument seems to mostly revolve around whether it is good to exercise first thing in the morning, before eating, which means a fasting state where glycogen stores are low. Given that you exercise in the afternoon, it does not seem as relevant to you, as if you ate a good breakfast your glycogen stores would likely be restored in any case.
To summarize, when you eat the fruit would not seem to play a significant factor in weight gain or other health factors. The much more significant factors would be the exercise type and intensity and your total caloric intake during the day. The post-workout meal is also likely to be more important.
Answer: That is too much fruit for one meal.  That is too much fruit for one day.  2-3 medium sized fruits (apple orange) is the recommended maximum.
A Closer Look Inside Healthy Eating Patterns
Strive for complex carbohydrates over simple.
If you want to fuel that afternoon workout then have a bowl of oatmeal for breakfast.
Comment: Thank you for the link, but the number of pieces of fruit was just an example.  Perhaps I shouldn't have even given a number in the question, as I guess my question boils down to "If the body is able to turn a certain food into energy quickly, are you better off eating that food shortly before exercise"


Can I use a flavored liqueur to make vanilla extract?

Question: Is it possible to make the extract with Crème De Cacao instead of vodka? I ask because I have some Crème De Cacao that I used in making a Grasshopper pie, but it is only "17.5"% (35 proof)" I don't know if this will be strong enough to do a good job, or should I half it with vodka?
Comment: Hello Jo, and welcome! That's a nice question you have. I edited the title so people will know what's about even before clicking to read the full text. Also, we prefer to not have greetings, signatures, etc. here - our questions are more of a "reference text" and less of a "personal correspondence" kind (comments like the one I'm writing now are seen more loosely). I hope somebody here will know if that works, and write you a nice answer!
Answer: One of the first things you'll need to consider is that the creme de cacao is already chocolate-flavored. Vodka is very clean and neutrally flavored, so if you use it to make an extract you'll get a very pure flavor extraction from whatever you're infusing. If you use something that's flavored already, the end result will obviously contain those flavors too. Basically, extracting vanilla flavor with creme de cacao will not give you a straight "vanilla" extract - it will be "chocolate-vanilla". That's not necessarily a problem, just be sure that you have the right expectation going in.
I do a fair amount of infusion at home (usually for cocktail use rather than baking, but the principles are similar) and have found that flavors tend to be best extracted in spirits that are at least 100 proof (50% alcohol by volume or ABV). Additionally, sugar can inhibit the flavor extraction. This makes your creme de cacao problematic because it's both not strong enough and contains quite a bit of sugar. I don't think you'd get a good extraction by using it on its own.
Simply blending with vodka might help, but only marginally. Most vodka is sold at around 80 proof (40% ABV) so if you did a half-and-half mix, you'd wind up with a solution at around 55 proof (the calculation of ABV isn't purely additive, so calculating the exact ABV would take some math that I'll attempt to add in later once I can track down the formulas). That's not enough of an increase in proof to make much of a difference - might as well just use the vodka at that point.
You could do better by using a stronger spirit. Some brands sell 100-proof vodka which would bring your half-and-half blend up to around 65 proof. It's possible to find some rums and grain spirits sold at 151 proof; blending with those would get you up to around 90 proof. You may even be able to find 190-proof grain alcohol under the Everclear label (though this is illegal in many jurisdictions) which if blended would bring you all the way up to 110 proof, which should be enough for a good extraction even given the sugar content in the mixture.
Of course, if you're going to seek out these specialty products, you could just use them on their own and get a much better, cleaner extract. If you're dead set on using the creme de cacao (or in the general case, any liqueur) you could probably find a way to make it work, but on balance I'd recommend finding a different use for it.
Answer: If you're trying to make vanilla extract, I wouldn't use a flavored alcohol... Even if it's feasibly possible in the lower-alcohol liquor (which I'm not certain of), you won't have the flavor you need... you'll have chocolate vanilla and, considering how strong the flavor is in most Creme de Cacao, I'd be surprised if you noted a change in the flavor at all.
The reason vodka is such a good option is that it's very high in alcohol and (assuming it's a good-quality vodka) it has a neutral flavor, so all you get is the vanilla in the end.


What does the Megillah mean when it says Mordechai was "dover shalom" to all his seed?

Question: Megillas Esther 10:3 tells us that Mordechai was great among the Jews and accepted of the multitude of his brethren; "seeking the good of his people and speaking peace [v'dover shalom] to all his seed."  What does the Megillah mean by v'dover shalom?  Is the reference to "his seed" literal, or is it speaking of the entire nation, as context would suggest?
Comment: Rashi says the entire nation's seed (i.e. it means "all *its* seed," referring to the לעמו previously mentioned). Most translations to English say his own seed.
Comment: Possible duplicate of [Did Mordechai have children?](http://judaism.stackexchange.com/questions/25717/did-mordechai-have-children)
Comment: @Sethj:  They are not duplicates.  ba is closer to where I am thinking -- that context suggests that Mordechai spoke peace to the entire community.  But that really is only half of the issue; how did he convey words of peace?  Did he urge tolerance for fellow Jews or the gentiles?  On the other hand, I heard a tape from Rabbi Frand that cites this verse as an instruction for child rearing.
Answer: Rabbi Shlomo Kluger explains this posuk according to what the gemara writes about Hillel, that once he was going on his way and heard an outcry in the city, and he said: I am certain that this is not coming from my house.
The Maharsha explains that Hillel did not think of himself as a tzaddik and for this reason he was certain that there would not be any outcry in his house. What he meant was that he had taught his household that even if, G-d forbid, a mishap occurred to
them, they should not cry out, but instead keep quiet and accept everything with joy, and bless Hashem for the bad in the same way that one blesses Hashem for the good.
One who teaches like Hillel did is called one who makes peace between Hashem
and the one to whom the mishap occurred, G-d forbid, by teaching them that they should not complain about Hashem's conduct and cry out, because then they would be making a quarrel between themselves and Hashem, but rather they should accept everything with joy and understand that the ways of Hashem are straight and everything that He does is for the
good. Thus with this he is making peace between them and Hashem.
This is what the posuk is saying, "And speak peace to all his offspring" - to his offspring Mordechai would command that whatever happened to them, whether good or bad, they should remain peaceful with Hashem and not complain.
The full text can be found here.


Why we don't see the "SkyRider" seats in action?

Question: In 2010 nearly all newspaper reported on the new invention of the company Aviointeriors.
They created new airplane seats called "SkyRider" which you can "stand" in. This should increase Airlines profitability.
I'm not a big fan of the SkyRider seats but who can I thank, or why don't we see them in Action?

Comment: Because they are awful, horrible things spawned by the minions of hades. Or the airlines, not sure which is worse.
Comment: @DavidRicherby Well, yes, *that* would, I'm saying they could put beds in planes and possible pack more people in as a result.  Just go with 3 high bunks, it'd be fun! ...or woefully impractical, take your pick.
Comment: If they really wanted to lay people flat they should just give everyone their own little bed.  We'd all be more comfy and they could fit more people in.
Comment: Was the announcement by any chance on April 1? It's hard to imagine that's a serious proposal.
Comment: @JayCarr Skyrider only counts as lying flat if the plane is in a vertical climb.
Comment: @JayCarr Too many people would start having sex.  Being in a position roughly equivalent to being duct-taped to a tree keeps everyone equal parts miserable and well-behaved.
Answer: There are a lot of disadvantages, even if the possibility of lowering costs and increasing profits is a huge advantage for the airlines. This article discussed several issues from a passenger perspective:

Limited space in general (e.g. to use a laptop)
Face too close to the video screen in front of you (if there is one)
Doesn't fit tall, large, short or young people well (and I guess that older people might not be strong enough to use it)
Very limited space for carry-on luggage (because you lose space both under the seats and in the overhead bins)
Passenger resistance to the basic idea

The author's conclusion was that the seat isn't actually uncomfortable, just cramped, but he was very sceptical that passengers would be willing to use it.
Another article added some concerns from the airlines' point of view:

Could make cabin evacuations more difficult (and certification costs in general would be high for a completely new seating concept)
Difficult to market successfully
The manufacturer intended the seats to be used in a new budget fare class, not to replace current economy class seats (this adds more complexity to everything: aircraft layout and maintenance, marketing, booking systems etc.)

Both articles (and others) concluded that there's no fundamental technical or regulatory barrier to introducing them, the main problem would be convincing passengers to accept them. Even Ryanair - which is notorious for cutting costs wherever possible - rejected them although Wikipedia says that both Ryanair and Airbus have proposed an alternative but very similar concept in the past.
If the airlines really wanted to introduce this seating arrangement, I would expect them to keep the idea in the news as much as possible and generally work on convincing people that the seats are comfortable and it's a great way for them to get even cheaper tickets. Since they haven't done that (if they have, I haven't noticed) it seems unlikely that the airlines are actively working on them.
Comment: Well, you use the overhead lockers completely, because you need at least 2.10 meters height for such a seat, while now there's surely less than 1.70 under the lockers since I'm far away from being able to stand there.
Answer: There are 2 major problems with skyriders

They need to be certified, just designing and showcasing them isn't enough to allow you to actually put them in planes. All that media buzz was to round up investors to get them through the certification process and get ready for mass production.
They are not one size fits all, as your second pic shows; overweight passengers will have trouble using the seats, same with children.

Then there is the "bad press" that got around. They would turn economy class even more into the sardine can than it is now.
Comment: These are both important problems, but I think the most important problem is that everyone would hate them. It would have to be a really, _really_ short flight and a really, _really_ cheap ticket for most people to consider purchasing such a seat. Even introducing them as a separate class would likely harm an airline's reputation with customers.
Comment: @ratchetfreak Most commercial flights involve being in the plane for at least an hour. Most bus journeys involve being in the bus for much less than an hour.
Comment: getting them on buses first would help to make people adjust to them


What is Surface termination and how to make surface termination of a crystal structure?

Question: I want to calculate the surface energy of CuO and for that, I've asked CuO (monoclinic) crystallographic plane and their relaxed surface energy. But for the lack of knowledge of the surface termination process, I didn't understand the answer clearly. Can anyone please explain to me about surface termination and how to do that for a monoclinic structure and how to calculate the surface energy of that surface termination. Basically I want to know the science behind it. Can anyone help me with some resources to understand it?
Answer: Determining a surface energy requires a few steps.

Calculate a bulk structure
Cut a surface termination manually or using a tool
Calculate the surface structure
Calculate the surface energy

I will try to provide some references to tools and methodology rather than attempting to describe this entire process since it is out of the scope of an SE question.
To do these calculations you will want to use some DFT software such as GPAW, VASP, CASTEP, SIESTA, or others.  I have just named the ones I have personally looked into but for these types of calculations any periodic code should work.  Most of these codes will interface with ASE, a python package which will generate bulk / surface structures for you.
Here are some specific references to surface energy and DFT as a whole.

Density Functional Theory: A Practical Introduction
Extracting convergent surface energies from slab calculations
Modeling materials using density functional theory

It may be more straightforward to collaborate with someone that already does this work that has shared interests, unless you wish to do computational work yourself.
Comment: @TristanMaxson thanks again. I think I can now begin the learning process. Once again in my University there is no one who works on these type of calculation. This is one of the problem I'm facing to work on these type of calculation. Many many thanks.
Comment: We can definitely assist you here, that was a large motivation in giving a general answer.  If you understand DFT you may be able to find others to assist in the future easier as well even if you don't continue to do it yourself.
Comment: That's very generous of you. I'll ask you if I need any help from you regarding this matter or any topics on matter modeling.
Answer:
What is surface termination?

The following figure should give you a clear understanding of the surface termination. Note that the vacuum should be large enough to avoid the interaction between slabs.

How to make the surface termination of a crystal structure?

There are lots of methods to realize this. For example, you can use ASE that Tristan Maxson recommended. Materials Studio (MS) and VESTA can also do that. To understand the details, I recommend VESTA for your system. For VESTA, you can find many tutorials on YOUTUBE, for example:

https://www.youtube.com/watch?v=ywR5pWqbllE
https://www.youtube.com/watch?v=iGC_FizUVAs
Comment: This answer could be a lot stronger (and more direct than mine) if you help explain how multiple [001] terminations can exist.  Adsorbates / vacancies etc
Comment: I can't talk more for this question. For the calculation of surface energy, you have provided a complete solution.


What is an artifact repository?

Question: What is an artifact repository?  If it's just a place to store files, can't I just use a source control system?
Answer: During development you generate a fair amount of different artifacts. These might include:

The source code
The compiled application
A deployable package
Documentation

and potentially others as well
While you could use a source control system to store all of them, it's usually massively inefficient, as source control systems are usually designed to handle text based files, and not binary files. You might be able to use them as a simple storage mechanism, if most of your releases are text based, and you don't have to store a lot of binary data.
Artifact repositories however are designed to store all kinds of files, including binary ones. This includes anything from zipped up source codes, to build results, to things like docker images as well. Also, they usually not only store these artifacts but also help manage them using various additional functions, for example:

Versioning support: properly store some metadata, like when each artifact was built, what their version number is, store their hashes, etc.
Retention: make sure you only keep the important artifacts, and automatically delete ones that are only snapshots / not needed anymore, etc. based on various criteria you can set up
Access control: set up who can publish and who can download the various artifacts
Promotion: ability to promote artifacts. For example you can have snapshot artifacts with a short retention period on a server near your coders, and a separate repository near the live servers, where only artifacts that have been deemed deployable appear. This also includes support for various version channels, and moving artifacts between them (like promoting a specific version from beta to stable).
Act as a native repository for the artifacts. Meaning you can use it as the main repository for maven, rubygems, docker, etc. This can also include caching of artifacts from the official repositories as well.
Comment: May worth adding the 'channel' capability over the Versionning support, having the ability to have some machine targeting the latest release in channel "develop" and prod machine targeting a specific version in channel "stable".
Comment: @Pierre.Vriens added some small comments, but maybe it can be addressed in a separate Question as well
Comment: merci, but just in case, [here](http://devops.stackexchange.com/q/466/40) is your chance to further address my additional comment ...
Comment: Does it makes sense to also keep track of configuration files or fixtures in these kind of repositories?
Answer: There's repository managers and Universal package repository managers (UPM).
UPM's can store all your build artifact for Jenkins, teamcity etc. and can generally also act as repository mangers for many different types of binary artifacts Maven, npm, NuGet and more.
These would be tools like Jfrog Artifactory, Inedo ProGet, and Sonatype Nexus.
A pretty decent comparison is here: https://binary-repositories-comparison.github.io/

What is an artifact repository?