Turn on Back To My Mac via a Script or Command Line

Question: The VPN software I use for work (IPSecuritas) requires me to turn off Back To My Mac to start it's connection, so I frequently turn off Back To My Mac in order to use my VPN connection (the program does this for me). I forget to turn it back on however and I'd love to know if there was something I could run (script, command) to turn it back on.
Answer: There is no supported way to do this. Having said that, you can do it using scutil:
louis@Arios:~$ sudo scutil
> set Setup:/Network/BackToMyMac
> d.add <YYY>  <XXX>.members.btmm.icloud.com
> set Setup:/Network/BackToMyMac
> quit
louis@Arios:~$

Replacing <YYY> with the UID of the user account on the system (for most people with  single account that is 501), and <XXX> with your iCloud account number. If you don't know that you can check your dns-sd registrations:
louis@Arios:~$  dns-sd -E
Looking for recommended registration domains:
 DATE: ---Wed 22 Aug 2012---
 9:11:04.789  ...STARTING...
Timestamp     Recommended Registration domain
 9:11:04.789  Added     (More)               local
 9:11:04.789  Added                          icloud.com
                                             - > btmm
                                             - - > members
                                             - - - > <XXX>

The last line will list your iCloud user number. I think they are all 8 digit numbers, at least mine is.
Comment: Nice work! I thought for sure the solution would have used `defaults`
Comment: You can do it using default to modify the underlying file ` /library/preferences/systemconfiguration/preferences.plist`, but the daemon running in the background won't pick it up, so you will need to kick configd and possible some other stuff after you do that. They all are signed up for a notification off the system config framework, so if you use that (which scutil does) it posts the notification after it does the equivalent of a defaults write.
Comment: Thanks a ton! Of note, this method doesn't allow me to see the other computers on the computer this is run on but works in order to see that computer which is precisely what I need. Of note, it doesn't even need you to be signed into MobileMe. This is a crosspost from Super User - if you'd like to answer it there as well.


is Cooler a "good guy" in Dragon Ball Heroes?

Question: In a Dragon Ball Heroes animation, Goku, Trunks, Vegeta and Cooler are seen fighting the saiyan who is going to be the bad guy in the new Dragon Ball Heroes anime. Is Cooler a "good guy" in Dragon Ball Heroes?
Comment: Well it is possible but we will not be sure until it comes out. It is quite likely the continuation of Frieza inclusion in the tournament, since Cooler is very similar to him and has the same transformation. Also, he too dislikes  the saiyans, so that could be a reason why he has joined the fight.
Answer: The answer to your question would be very likely be a No. Cooler is an antagonist and is a character who wants to eradicate the Saiyans just like Freiza. There is absolutely no reason for him to turn "Good", as that would imply, Cooler would be willing to fight Frieza to protect Goku and the rest of the Saiyans, which doesn't make sense. Cooler certainly hates Frieza and would destroy him if he had the chance. You could compare it to a relationship between Early Vegeta and Goku, where Vegeta would destroy Goku by himself if he could but you wouldn't necessarily see him join an arch enemy like Frieza and help him defeat Goku.I believe just like Dragon Ball Fighter Z and even in the tournament of power, Cooler has possibly teamed up with the Saiyans to take out an even greater threat.


Round of 16 champions league

Question: How will the round of 16 draw work. 1 pot group winners, 1 pot runners up, yet Liverpool can't play PSG or Man City so what happens if they are drawn together
Comment: Related: [In UEFA Champions League, how is it ensured that two teams from the same Country aren't drawn into the same group?](https://sports.stackexchange.com/q/14597)
Answer: It's pretty simple actually, because there are only two rules:
(source)

Teams from the same group may not be drawn against each others.
Teams from the same association may not be drawn against each others.

Liverpool played PSG in the group stage and City is from the same association, that's why those match-ups are not possible in the next round.
This is done as follows:

All runners-up are placed in one bowl.
All group winners have an own bowl each.
When a runner-up is drawn an empty bowl will be filled with all possible group winners, eliminating the possibility to draw an ineligible opponent.
When there's no need to draw (e.g. one eligible opponent left) the match will be placed directly.
If the last match would become invalid the previous match is selected directly. This happened in the 2016 round of 16 draw.

A computer helps by showing any (in)eligible opponents when a runner-up is drawn.
Comment: But what would happen if PSG were drawn against LFC. What would the next step be. Would another ball be taken out of the pot until PSG have a suitable match and then LFC are put back in the pot for the next draw. What happens if PSG and LFC are the last two teams left in the draw in the round of 16, how does this all work.
Comment: @DANZERELLI I appened more details now.

Round of 16 champions league


What is the importance of intention in Buddhism?

Question: Do any scriptures discuss the importance of intention? Why is intention rather than action important?
Answer: From the Nibbedhika Sutta:

"Intention, I tell you, is kamma. Intending, one does kamma by way of
body, speech, & intellect.

Also from Cetana Sutta (SN 12.38) below, we see that intention (cetana) provides a landing point for the continuation of karmic consciousness.

[the Blessed One said,] "What one intends, what
one arranges, and what one obsesses about: This is a support for
the stationing of consciousness. There being a support, there is a
landing [or: an establishing] of consciousness. When that
consciousness lands and grows, there is the production of renewed
becoming in the future. When there is the production of renewed
becoming in the future, there is future birth, aging & death, sorrow,
lamentation, pain, distress, & despair. Such is the origination of
this entire mass of suffering & stress.

The story of blind elder monk Cakkhupala from Dhammapada 1 shows the importance of intention:

On one occasion, Thera Cakkhupala came to pay homage to the Buddha at
the Jetavana monastery. One night, while pacing up and down in
meditation, the thera accidentally stepped on some insects. In the
morning, some bhikkhus visiting the thera found the dead insects. They
thought ill of the thera and reported the matter to the Buddha. The
Buddha asked them whether they had seen the thera killing the insects.
When they answered in the negative, the Buddha said, "Just as you had
not seen him killing, so also he had not seen those living insects.
Besides, as the thera had already attained arahatship he could have no
intention of killing and so was quite innocent."
Verse 1: All mental phenomena have mind as their forerunner; they have
mind as their chief; they are mind-made. If one speaks or acts with an
evil mind, 'dukkha' follows him just as the wheel follows the
hoofprint of the ox that draws the cart.

Also the story of the hunter's wife from Dhammapada 124 shows the importance of intention:

The bhikkhus then asked the Buddha, "Venerable Sir, is the wife of the
hunter who is a sotapanna, also not guilty of taking life, if she has
been getting things like nets, bows and arrows for her husband when he
goes out hunting?" To this question the Buddha answered, "Bhikkhus,
the sotapannas do not kill, they do not wish others to get killed. The
wife of the hunter was only obeying her husband in getting things for
him. Just as the hand that has no wound is not affected by poison, so
also, because she has no intention to do evil she is not doing any
evil."
Verse 124: If there is no wound on the hand, one may handle poison;
poison does not affect one who has no wound; there can be no evil for
one who has no evil intention.

So, intention is kamma. You can see in this question that buying frozen meat from the supermarket does not incur the kamma of killing, because there was no intention or action to kill.
But does this mean that intention without acting upon the intention can result in kamma?
According to the Yodhajiva Sutta:

When a warrior strives & exerts himself in battle, his mind is already
seized, debased, & misdirected by the thought: 'May these beings be
struck down or slaughtered or annihilated or destroyed. May they not
exist.' If others then strike him down & slay him while he is thus
striving & exerting himself in battle, then with the breakup of the
body, after death, he is reborn in the hell called the realm of those
slain in battle.

Here, the warrior has the intention. But when he strives and exerts himself based on the intention, then the fruit of the kamma reaches its peak.
Despite this, thoughts are also kamma that can result in suffering. From Mahakammavibhanga Sutta:

After doing an intentional deed to be experienced as pleasant by way
of body, speech, or mind, one feels pleasure. After doing an
intentional deed to be experienced as painful by way of body, speech,
or mind, one feels pain. After doing an intentional deed to be
experienced as neutral by way of body, speech, or mind, one feels
neutral."

Also the Bhumija Sutta:

"When there is a body, pleasure & pain arise internally with bodily
intention as the cause; or when there is speech, pleasure & pain arise
internally with verbal intention as the cause; or when there is
intellect, pleasure & pain arise internally with intellectual
intention as the cause.

OP: so how do these teachings influence Buddhists?

You can see in this question that buying frozen meat from the supermarket does not incur the kamma of killing, because there was no intention or action to kill.
Another example is the case where if you give money to a beggar, he might use it to buy alcoholic beverages. Some people may have the idea that if the beggar uses the money to buy alcoholic drinks, then they would share in the kammic consequence. However, in this case, the kamma is based on the intention of the giver. If you gave the money with intention to help the beggar buy food, then the result will be good (assuming that the beggar hid his intentions from you).
Comment: so how do these teachings influence Buddhists?
Comment: @Hari Updated answer.
Answer: The bodily action and the verbal action are just a body. The body can not act  without vedanā, saññā, cetanā, and cittā.
Without it, the body is like a piece of wood in sutta.
See, cittajarūpa in advance.
Answer: Intention readies the body for action and may direct emotion.
Intention is directed conscious energy. When we think about doing something, where does that energy go? Thoughts like these are created before every conscious action as a means to mitigate the quantity and quality of the repercussion. If an individual cultivates an intention enough, the chances of inadvertently performing the action is more within reason.
If someone who has always been afraid of heights, but want to jump into the water more, they will jump into the water because they have reinforced with their mind they can jump in the water. The next time they go to jump from the same place, they will have less self imposed restrictions. This applies to any cultivated behaviour.
Another reason why buddhism has such interest is the repercussions of cultivating intention directly involve the the law of karma (cause and effect).
In a nutshell, our intentions carve worlds and therefore, not to be underestimated - yet this is something to be learned by every individual. The emphasis used is a subtle reminder for those who have yet to learn.
Cultivate in harmony
Comment: Intention is directed thought energy. This answer is wrong & illogical. When it says: "If an individual cultivates an intention enough", it appears to be saying the actions performed without reason are not intentional. This is obviously wrong.


MacPro 1st Gen - can it handle SSDs?

Question: I have a MacPro 1,1 and am considering putting an SSD in it to give it a boost. Can I safely assume compatibility or will its ancient  hardware and architecture cause issues? It cannot, as I recently discovered, run Mountain Lion so I'm not sure if I should even try bringing it up to date.
Answer: Yes, I can confirm that I have installed an SSD into my Mac Pro 1,1. Because the drive is a 2.5" drive, though, I am using a 2.5" to 3.5" SATA converter sled. Note, if I recall, there are some of these converters that only work with certain models.
Answer: Definitely confirm the claim that you can use an adapter before you go out and buy SSD drives.  I have a MacPro 3,1 with the Apple RAID controller.  I was told by a couple vendors specializing in hardware upgrades for Macs that the adapters being sold now fit the current production Mac Pros, but not the 3,1.  Yours is even older.  There have been some changes to the drive carriers.
I'd very much like to hear of any source for an adapter that will definitely work the the 3,1 or earlier models.
Answer: Ia m using a Quad 3.0 Ghz MacPro with an SSD from OWC. They have an adapter that connects the SSD to the original sled and works great. I created a boot disk with Mac OSX 10.7.5 Lion and then used Carbon Copy Cloner to move all the data from my old boot drive. Boots in about 8-10 seconds and runs Photoshop faster than the 8 core brand new MacPro my friend has. I also bought a replacement sled which is only supposed to work in the 8 core machine. It works fine but you can't put the side cover back on the tower because it sticks about an inch to inch and half further. I still use it when I want to replace an old drive or format a new one. And I can keep an off line data drive to swap in an emergency.

MacPro 1st Gen - can it handle SSDs?


Why must twin-lead conductor spacing be small to avoid radiation?

Question: A transmission line does not radiate when the spacing between the two wires is very small when compared to the wavelength, but the transmission line begins to radiate when the spacing between the lines becomes comparable to the wavelength of the signal. Why is this?
Answer: Twin-lead transmission lines don't radiate because the opposite fields from each conductor cancel, but when the spacing is far apart this does not happen.
First, let's consider the magnetic field around an infinite, straight conductor with uniform current throughout. In this image, the conductor is just right of center, and the current is coming straight out of the page.

Now let's add next to it another conductor, with the current going the other way:

Add these fields together, and you get:

For distances far away relative to the conductor spacing, the fields are equal but opposite, so when added together they cancel. Radiation is, by definition, a field that extends to infinity. If there are no fields far away, then it can't be radiating.
However, we made an assumption of uniform current. When the spacing between the conductors is small, this is a mostly true assumption. Although the current isn't exactly uniform, we must travel many multiples of the conductor spacing before there's any appreciable change in phase.
However, when the conductor spacing is large, then this is no longer true. Remember, the current is reversing direction periodically, and if we look at the field from just one conductor this means the field is alternating between clockwise and counterclockwise swirl. The changes to this field only propagate at the speed of light, so if we zoom the graph out to be a wavelength wide or more, we'd see those changes propagating away as waves.

In the image above, the wavelength appears to be approximately four units. Now if we add that second conductor, two units away, we get this:

Notice how the fields don't cancel. They don't cancel because on the scale of the conductor spacing (which is not small relative to the wavelength) there can be significant changes in phase. Thus, there are regions of constructive interference where the fields don't cancel. These regions extend out to infinity, and thus, the feedline radiates.

Images were generated with a Javascript vector field grapher by Kevin Mehall
Comment: This is good. However, depending on the spacing and frequency, there is an *approximate* distance from the line where the radiation is insignificant. I realize that there are a lot of variables; but --if it's not a lot of trouble-- could you please go a little further and calculate a few real-world numbers using 1", 2.5", and 6" spacing at 3.5 MHz? (160 through 18 would be even better! ;-) Assume that there is no metal near the feedline from the antenna to a good tuner.


Filling an 11-by-11 square

Question: Is it possible to fill the $121$ entries in an $11\times11$ square with the values $0,+1,-1$, so that the row sums and column sums are $22$ distinct numbers?
Comment: I suspect that it is impossible for all odd sized squares, given that it's easy to brute force squares 3x3 and 5x5, and those have no solutions.
Comment: I ask this question of mathoverflow, it is impossible, see http://mathoverflow.net/questions/228525/reverse-definition-for-magic-square
Comment: @Gamow Do you know the solution?
Comment: Seems like a relatively simple dynamic programming or backtracking problem
Comment: @Gamow please feel free to answer question for bounty.
Comment: I imagine the answer is no if no-one has got it yet
Comment: @MeysamGhahramani The joy in doing these problems is found in personally (or with others in real-time) deriving an elegant, general proof, possibly going through an ugly, specific case. Admittedly, we are (or at least I am) currently at an ugly detour stage. Nevertheless, thank you for noting the solution - it gives some incentive to continue the journey.
Comment: is there a solution or people are wasting their time to proof it is not possible?
Answer: I've found a solution here, which I've decided to blatantly steal since I think a lot of people really want to see a fully worked out solution. It is indeed impossible. The same method below can be used to show that a valid $n\times n$ matrix can only exist if $n$ is even and the missing sum is $\pm n$.
Let's say the missing sum is $m$. We can assume by symmetry that $m\le 0$. There are 11 rows and columns whose sum is positive. Let's rearrange these positive row/columns so that they are all on the top/left of the matrix. Assuming there are $r$ positive rows, this means there are $11-r$ positive columns. Let's group all the positive columns on the left, and all positive rows on top. See the picture at the bottom, where I've given labels A, B, C and D to four quadrants of the matrix.
Now, let $a$ be the sum of the numbers in section A, and the same with $b,c,d$. Then
$$\begin{align}
a+b+c+d
&=(\text{sum of all rows and columns})/2\\
&=((-11)+(-10)+\dots+11-m)/2\\
&=-m/2
\end{align}$$
We also know that
$$
\begin{align}
(a+b)+(a+c)
&=\text{sum of all positive rows/columns}\\
&=1+2+\dots+11\\
&=66
\end{align}$$
Combining these last two observations,
$$
-m/2=a+b+c+d=(2a+b+c)-a+d=66-a+d
$$
Here's the kicker. There are $r(11-r)$ entries in section $A$, meaning that $a\le r(11-r)$. No matter what $r$ is, the quantity $r(11-r)$ is at most $30^*$. Similarly, $d\ge -30$. This means that
$$
-m/2\ge 66-30-30=6,
$$
implying that $m\le -12$, a contradiction.

${}^*$ To make this proof to work for a general $n\times n$ matrix, instead of just $n=11$, use the inequality $ab\le (a+b)^2/4$, which shows $r(n-r)\le n^2/4$. We then get that $-m/2=\frac{n(n+1)}2-a+d\ge \frac{n(n+1)}2-\frac{n^2}4-\frac{n^2}4=n/2$, implying that $m\le -n$, which means $m=-n$. Since the missing sum must be even, this means $n$ must be even.
Answer: Partial answer (fixing earlier mistake)
The possible outcomes of a sum of 11 values (0, +1 or -1) can be any integer number from - 11 to + 11, leaving 23 options total.
Theory on combining resulting numbers:

It's fairly trivial to state that if '11' occurs (a row/column with all 1's), there can never be a column/row totalling '-11' or '-10', due to one of the rows/columns holding a '1' (you can at lowest reach -9 then). The other way around, you cannot have '-11' and expect to be able to squeeze in 10 or 11.

What we learn from this:

11 and -11 cannot occur in scenario's with one of them in a column, and the other in a row

Note: the above is where I went wrong: I first assumed they couldn't appear together at all, which is false - as pointed out in the comments
For ease of further explanation, assume both 11 and -11 to be in rows (all that follows would be similar but mirrored along the diagonal).

 If 11 and -11 both take up an entire row, this means in columns you can at extremes reach -9 and +9. If we want 10 and -10 to be able to appear, those have to be in rows aswell (with 10x '1' or '-1' and one zero). This means we already have 4 rows occupied.

It now gets harder though:

 if we aligned the 'zeroes' from the '10' and '-10' rows below eachother, we can get at most +7 and -7 in a column, if we didn't we can get +8 or -8 at most. Either way we can only create +9 and -9 in rows again. We can do this two ways: 9x '+-1' and 2x 0, or 10x '+-1' and 1x '-+1'

What can we squeeze into columns now?

 so far, the rows from -11 and 11 cancel eachother out, the rows from -10 and 10 allow for a maximum of +1 or -1 variance on the two rows occupied, and the rows from -9 and 9 for a +2 or -2 variance on the two rows those occupy. So with 5 rows left a column value can now hold at most +-5 (+-3) , which also implies we can now actually squeeze our next step (+8 and -8) into columns.

Option 1: Put the '8's in columns.

 This means we've used up all variance on the remaining 9 columns, so we have 9 columns which can at most hold +-5. This also implies both 7's and 6's will have to go in rows. The 11's, 10's, 9's, 7's and 6's hog a combined 10 out of a possible 11 rows.  Is there a way to build the 7's and 6's in the column's that leaves sufficient different value numbers to be built in the colums? This will most likely imply 7's and 6's to be built to a maximum from -1 and +1's rather then 0's, to allow sufficiëntly high values in the collumns). Key might be to try and ensure the presence of the +-4 and +-3 in the colums as a guide to figure out how to place the several +-1's to create 6/7 rows.

Option 2: Put the '8's in rows

 It's not because we CAN put the 8's in columns, we have to.

Option 3: Put one of the 8's in a column, the other in a row.

 Besides option one and two, there's still a third option, and that's to go both ways.

I may have to put this train of thoughts on hold for now, as there doesn't appear a simple path further down. The thing is: The more you keep pushing things with very similar patterns for the '+' and '-' variation in rows, the bigger the chances you'll have issues fitting in 5's and 4's in columns. If the '+1' and the '-1' from the '+' and '-' version of the larger sums keep cancelling eachother out in the column totals, suddenly it appears 4's and 5's turn seemingly impossible to fit in. (or maybe I just haven't spotted how).
Comment: That was my first thought also initially but both 11 en -11 can exist easily. fill the first row with +1 and the second row with -1. It's just that when a row has 11 a column can't have -11
Comment: @TimCouwelier but I think this is the right track to take. Let's say that if both 11 and -11 exist and they both are rows you also know that the columns can only range from -9 to 9 meaning that -10 and 10 also must be rows, and maybe you can go on like that
Comment: @dmg - thanks for the spoiler edit - I'm somehow always struggling to put multi-line blocks in spoilers
Comment: @IvoBeckers : Oh dear. This seemed to easy for a question by gamow.. I'll try to build on it though
Comment: @TimCouwelier You can use  for line breaks in spoilers.
Answer: Partial answer
As Tim pointed out

 If you have rows with sums of -11, 11 and 10, that quickly limits the different numbers you can generate in the columns. Experimentally you can fit in ±11, ±10, ±9, ±8, ±7, ±6 and ±5 but there isn't anywhere to put ±4. If I miss out -10 then I can get to ±3 but there isn't anywhere to put ±2.

And the big problem is that

 you need at least ±11 and one of ±10 just to be able to complete the square.

This is because

 the row and columns use 22 of the 23 sums but they must sum to the same number so the missing sum must be even.

By contrast, even squares are quite easy; there's a simple pattern whereby you fill a 2n square with n 0s, 2n² 1s and 2n²-n -1s. (Hint: 2n²-n = 2n(2n-1)/2.) Example for 6x6:

 1  1  1  1  1  1  61  1  1  1  1 -1  41  1  1  1 -1 -1  21  1  0 -1 -1 -1 -11  0 -1 -1 -1 -1 -30 -1 -1 -1 -1 -1 -55  3  1  0 -2 -4

My best effort so far for 11x11:
 1  1  1  1  1  1  1  1  1  1  1 11
 1  1  1  1  1  1  1  1  1  1  0 10
 1  1  1  1  1  1  1  1  1  0 -1  8
 1  1  1  1  1  1  1  1  0 -1 -1  6
 1  1  1  1  1  1  1  0 -1 -1 -1  4
 1  1  1  1  0  0  0  0 -1 -1 -1  1
 1  1  1  1 -1 -1 -1 -1 -1 -1 -1 -3
 1  1  1 -1 -1 -1 -1 -1 -1 -1 -1 -5
 1  1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -7
 1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -9
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -11
 9  7  5  3  0  0  0 -1 -4 -6 -8

As you can see ±2 are missing, but I'm sure that the fact that you can't get those diagonals to meet must be a factor somehow.
Comment: Didn't I answer that in my third spoiler?
Comment: If you make one of the zeros in the 5th, 6th, or 7th columns a 1, you'll get a 2 on the right side and a 1 on the bottom, getting you a step closer.
Comment: Could we, based on the column/row sums matching, figure out that if only 22 out of 23 possible combinations are formed, which of the 23 are options for the one NOT being used? (I.E. '0', 'any odd number', 'any even number, ..') This could make it easier to figure out if any number strictly HAS to be in there.
Answer: Taking the example:

for $n=6$, where the greyed cells are the totals of their respective columns and rows, and the top-left cell is the total of each greyed column/row, I am fairly certain that it is not possible for the following reasons:
1)    The top-left cell must $=\pm n/2$
2)    The only excluded integer in the range $[-n,n]$ must be either $-n$ or $n$.
As noted by @kaine below, these statements are identical, so a proof of either would be enough to show that solutions are not possible for odd $n$. Both are purely observational though, and the bounty will go to a proof  (or disproof?!) of the above.
NB
This Mathematica code doesn't check all possiblilities (rather large for $n=11$), but checks the most likely (and returns nothing for test@11).
Comment: 1) and 2) are identical.
Comment: Um, I'm not sure what you mean by that.  I just mean that since the sum of all rows ($R$) equals the sum of all columns ($R=C$) which equals the sum half the sum of all numbers ($\sum_{x=-n}^nx=0$) minus the missing number $y$.  This means $\sum_{x=-n}^nx-y=R+C$ goes to $R=C=-y/2$.  If you assume 2, 1 is true.  If you assume 1, 2 is true.  Those two statements are indistinguishable.
Comment: @kaine that's because I've set the tollerance to only include 1 zero per row/column (reduces computation for larger $n$). Can provide complete code for $n$ if desired, but computational time increases exponentially (hence cutbacks). Please let me know if you require complete solution code.
Comment: @kaine alternatively, increase tollerance by adding `&& \[Or] Count[#, 0] == 2`, etc. to `test[n_]` function. I addition to including *all* zeros, for complete check, change `Subsets` to `Tuples`. You will see then why I cut back!
Answer: This is not possible.
Of course, the more interesting question is the generalized solution to:

Given a square with $N$ columns and $N$ rows, is it possible to have $2N$ unique sums of columns and rows?

First, we need to consider two properties of an $N\times N$ matrix:

For a given matrix with $N$ columns and rows, the range of possible value are $2N + 1$ (in the range $[N, -N]$) and $2N$ sums of values ($N$ columns and $N$ rows). This means there is $1$ and only $1$ "missing value" $M_v$ in the series.

There are also $N^2$ places to fill. This means we need to be at least efficient enough to have $2N$ values using $N^2$ places.

Next, consider a matrix where $N$ is even and it has $2N$ unique sums:
First, assume $N = M_v$. By placing values in the left column and upper row starting with $-N$ descending, we can place unique, sequential values until there are 2 columns and 2 rows remaining. At this point, the sums of all the columns and rows adjacent to the $2 \times 2$ matrix is $0$. It is then trivial to demonstrate that this matrix can produce the remaining values required. This same technique also works when $-N = M_v$.
Since we have $2N$ values to produce, and with each iteration we produce 2 unique values, we cannot be less efficient or else we cannot produce all of the required values. However, when $N$ is odd we should note another property of the matrix:

Each value $(1, 0, -1)$ added to the matrix will result in an even change to the sum total of the matrix columns and rows. Therefore the sum of the columns and rows must be even.

Also note that sum of the columns ($C_v$) and rows ($R_v$) is equal to $-M_v$. ($C_v + R_v = -M_v$ or $C_v + R_v + M_v = 0$). This means that $M_v$ cannot be odd because it is impossible for the sum of the columns and rows to be odd.

So, when $N$ is odd, the missing value $M_v$ cannot be $N$ or $-N$.
That leaves only the possibility of including both $N$ and $-N$ in the matrix, but to do this we must put them both in columns (or rows). Once this is done, observe that there are $N - 2$ columns and $N$ rows (or vice versa) remaining. This allows for $N + (N - 2) = 2N - 2$ unique sums of columns and rows but leaves only $N(N - 2) = N^2 - 2N$ places.
For example, when $N = 11$, after placing $11,-11$ we now have $9 + 11 = 20$ sums but only $9\times 11 = 99$ places. Previously, we demonstrated that for $2N$ values we needed $N^2$ places which, for $N = 10$, is $20$ sums and $100$ places. So when $N$ is odd, after placing $2$ numbers ($N$ and $-N$), we have to be more efficient in order to succeed. Maybe a rectangle can be more efficiently filled (requires fewer available spaces) than a square matrix?
With that assumption, after placing $N$ and $-N$, we can continue to place sequential numbers (like $N-1$ and $-(N-1)$) but that will fill columns (or rows) very quickly (approaching $N + N/2$ instead of $2N$ sums) and reduce the "available spaces" below $N^2 - 2N$ making it easier to consider $M_v$ as $N-1$ or $-(N-1)$.
So if we can skip either $N - 1$ or $-(N - 1)$ then we will explore further. To start we can try the alternating values in columns/rows that we used when $N$ was even. That produced 2 unique values for each column/row pair that was eliminated. It is not possible to be more efficient than that. However, after placing $N$, $-N$ and either $N - 1$ or $-(N - 1)$, we have used 3 columns (or rows) almost entirely identical. The third column contains a $0$ that must be in the second from the top position to allow $N - 3$ in the second row.
If we subtract a row for each column as is required, until there remains only 1 column. Based on the pattern as described above there will be $4$ rows ($4$ remaining spaces; with an even numbered matrix, the 4 remaining spaces were in a square, not a column). However, there are only $3$ possible values (1, 0, -1). This will result in a duplicate value being placed. A duplicate value means a second "missing value" somewhere else in the matrix, since we cannot increase the number of sums produced. This means we cannot have $22$ unique values for an $11\times 11$ matrix (or any odd sized matrix). We can, at most, have $21$ unique values (or $2N - 1$).
Thus, even if it is possible to efficiently fill a square of size $N$ where $N$ is odd, the constraints on how the values are placed reduces the number of unique sums to below $2N$. (Note: I think there is a method to prove that when $N = 11$ there can be at most $19$ unique values, but I'm still working on it...)
Comment: I have a lot of trouble following this answer and can't really understand what's going on in the last paragraphs. It could use some clarity, even after the edit.
Comment: Well, I haven't actually bothered to read your answer, but I have 2 points to make. 1. Use MathJax. Your equations are fairly simple, you could learn MathJax to type them out. 2. You have used too many spoilers. You could just state at the top in bold letters, that this is a partial proof. The whole objective of spoilers is that people don't read the answer by accident, and I don't think that is going to happen anyways for such a long post.
Comment: Thanks for the pointers... I'm looking at MathJax. And I'm not sure how to use spoilers, so I'll try to edit it to improve it after looking at that.
Comment: Your last statement that for $N=11$ there can be at most $19$ unique values isn't correct. I have created multiple squares with $21$ unique sums.
Comment: What if the number skipped isn't (N-1)? It could be '0' or '2' that's left out. Some visual aids (filled grids) along with your steps would help. (I know, not done that myself - but I didn't end up with a working solution yet either.. )
Comment: Thanks for the comment. I am trying to add visual aids - the proof I've provided does not require N-1 be skipped - I think that part was edited out because if you keep N-1 and -(N-1) the grid becomes rapidly filled, such that the number of sums produced is about N + N/2, not 2N. I agree that visuals would help.
Comment: Shouldn't the first $2N-1$ be just $2N$ (e.g. with $N=11$ we want $2\cdot 11=22$ unique sums)?
Comment: Thanks for noticing that - I edited that (and a few other things) to help clarify. I'm still trying to figure out useful graphics without making the answer even longer.
Answer:
 I don't know yet

I used a simple backtracking approach. The code is here: https://gist.github.com/smaspe/bb7efc8e03e8eaa81629
It basically tries to recursively fill the matrix and prunes the inconsistent branches as soon as 2 identical sums are found on a complete row or line.

 it is currently running.
Comment: Simple backtracking won't be fast enough in Python unless you employ some tricks
Comment: I tried changing all the instances of `11` to `2` (for which I know a solution exists, e.g. `[[1, 1], [-1, 0]]`) and your code returned `None 13 9` instead of a valid grid.
Comment: Pasting your code here: https://repl.it/BcE3/0
Comment: @2012rcampion right. I don't know how I though that was complete. Plenty of things missing...
Comment: @2012rcampion I updated the file. It works for small numbers (however, because it starts by considering `-1`, the solution offered for 2 is -1, -1, 0, 1). It is still running for 11, though.
Comment: @qwr yes, I am beginning to realize that.
Answer: My best try so far:
 1   1   1   1   1   1   1   1   1   1   1   11
-1  -1  -1  -1  -1  -1  -1  -1  -1  -1   0  -10
 1   1   1   1   1   1   1   1   1  -1   1   9
-1  -1  -1  -1  -1  -1  -1  -1   0  -1   1  -8
 1   1   1   1   1   1   1  -1   1  -1   1   7
-1  -1  -1  -1  -1  -1   0  -1   1  -1   1  -6
 1   1   1   1   1  -1   1  -1   1  -1   1   5
-1  -1  -1  -1   0  -1   1  -1   1  -1   1  -4
 1   1   1  -1   1  -1   1  -1   1  -1   1   3
-1  -1   0  -1   1  -1   1  -1   1  -1   1  -2
 0  -1   1  -1   1  -1   1  -1   1  -1   1   0
 0  -1   2  -3   4  -5   6  -7   8  -9  10

As you can see, the sum of 1 is missing, instead I end up with 0 twice.
I also suspect that there's a problem with symmetry after one row or column is filled with all 1s or -1s, but I really have no idea how to prove that yet.
Comment: it is always possible to generate such grids for odd $n$ with something like `oddsol[n_] :=
 Table[Flatten@Join[#[[All, t]]] &@{ConstantArray[1, #] & /@
     Range[0, n - 1],
    Join[{0} & /@ Range[(n - 1)/2 + 1], {1} & /@ Range[n/2]],
    ConstantArray[-1, #] & /@ Reverse@Range[0, n - 1]}, {t, n}]`. Then a`oddsol@11` gives the same as your solution.
Comment: Your build-up can never work. Due to the way it's counted, the 'sum of row sums' and the 'sum of column sums', always have to be equal. This means that the sum of all numbers constructed (which is total of the two previously mentioned sums), by definition is EVEN. This means that from the total you'd have with 23 values (netto being '0'), you can only have an EVEN difference. The number you leave out has to even, and therefor you cannot have a solution leaving out '-11'. And as stated before, -11 and +11 can only co-exist in the grid if both in rows. And out goes your symmetry..
Answer: Partial Solution:

 We can't have all of {11, -11, 10, -10, 9, -9, 8, -8, 7, -7, 6, -6} in the solution.
 Because {11, -11} would obviously have to be in rows (11 in a column and -11 in a row doesn't work since -1 and 1 can't occupy the same place).
 This is without loss of generality (because all in columns or all in rows are symmetrical).  Call these rows R11 and R-11.
 Now {10, -10} have to be in rows as well because there's no room in the remaining columns.  Call these rows R10 and R-10.
 Similarly {9, -9}, {8, -8} and {7, -7} all have to be in rows. Call these R9, R-9, R8, R-8, R7, R-7
 Now we have one row left and the maximum we can put in a column is 5 (using 1 from R10, 0 from R-10, 1 from R9, 0 from R-9, 1 from R8, 0 from R-8, 1 from R7 and 0 from R-7 and then 1 in the remaining empty row).
 So we have no room left for both 6 and -6.
 Therefore we have to get rid of one of {11, -11, 10, -10, 9, -9, 8, -8, 7, -7, 6, -6}.
 Say this number is n.
 Now the sum of the totals for the rows and the columns is -n.
 This is also 2 * (the sum of all the elements in the matrix).
 So n must be even, and without loss of generality we can say n = 6, 8 or 10.
 Now we need 22 numbers (11x11 matrix) from 23 numbers [-11, 11].
 So the numbers are [-11, 11] with 6, 8 or 10 removed.
 And the matrix must have R11 and R-11.

Far as I've got.
Comment: This is not true, we can have 8 or -8 in columns when 11, -11, 10, -10 and 9, -9 are in rows.
Comment: @Fimpellizieri You're right! But then R9 and R-9 would have no zeros. And C8 or C-8 would have to use one of the zeros from R10 and R-10. So maybe it goes down to {-11, 11, 10, -10, 9, -9, 8, -8, 7, -7, 6, -6, 5, -5, 4, -4} and we need to lose 10, 8, 6 or 4.  I think by this logic we can certainly conclude that we need 0 and have to lose an other even number at the very least.
Comment: @Fimpellizieri Going to try to stick with a proliferation of zeros as a need to produce both positive and negative lower numbers.  Without them you need equal numbers of 1s and -1s before you can start counting.  So we can't get the even lower (or otherwise) numbers without at least one zero.
Answer: It is not possible if the matrix is odd x odd.
I suspected this by trying the same problem with 4x4 and got a solution: the logic was obvious. There has to be 4+4 distinct numbers, and with -1,0,1 you could find 9 different sums: -4,-3,-2,-1,0,1,2,3,4. There is no solution if you use -4 and 4 at the same time since they have to be in the same row/column. Only solution would be without any of them as below;

So I tried it with 3x3 and 5x5 and I stuck at the same point where you are supposed to put -1,0,1 and there was no possible solution;

Wrote an program that tries to find possible solution with a basic algorithm and it could not find a solution either.
But I can show that it is not possible to have all distinct sums. Firstly, there has to be 22 different numbers and 23 different values you can have by summing rows and columns as states above. First of all I will show you it is not possible to have 11 and -11 at the same time;
If you want to use 11 and -11, there has to be on the same row/column as below;

So you have to have at least one 10 and -10 in this possible solution and you have to put it on the row again since it is not possible to have any of them on a column any more;

So you cannot have -10 any more in this possible solution and you have to use all other possible sums since if you put -1s and one 0 in the row, you will not able to have -9 and 9 any more and there is no way to find a solution any more. So we have to use only one -11 or 11 as below as a start;

since you will have only one 11 or -11, you have to have -10 and 10 at the same time in the solution so only possible solution for this as above.
Then, you need to 9 and -9. You cannot put -9 on the row since you will not able to find 9 any more, so -9 has to be on the column and 9 on the row:

same goes for 8 and -8 and it goes to a point;

So this is the same problem for a oddxodd matrix where you cannot find a solution after this point as 5x5 and 3x3.
As a result, there is no solution and it is not possible!
Comment: "if you put -1s and one 0 in the row, you will not able to have -9 and 9 any more" - yes you can, if the 0's in the 10 and -10 rows are not in the same column. Also, we already know that if there is a solution, 11 and -11 must be present.

Filling an 11-by-11 square


UK Visa in Old Passport with Maiden Name

Question: My visa is in my old passport with my maiden name in it. I was issued a visa in 2014 and there was no BRP at this time yet so I don't have a BRP. I got married and have a new passport. I want to go to holiday outside UK. Shall I apply for a BRP? or can I just show my old passport and new passport? I have informed home office using the change of circumstance form (for visa).
Answer: Assuming your 2014 visa is still valid, bring the old passport containing that visa, the new passport, of course, and your marriage certificate (to document the change of name).


Can I "pin" my favorite boards to the top of the Trello window so I can switch between them easily?

Question: I'd like to be able to switch between my favorite boards easily.
Answer: It's actually much better to use browser tabs to do this.
If we were to allow you to "pin" boards to a navigation bar across the top of the Trello window, we'd have two choices:

Keep all the data for all those boards loaded in real time, or,
Do a full reload of the page every time you switched between browsers

Neither of these is a great option, so the best thing to do is use the tabbed browsing functionality already in your browser.

You can even bookmark your favorite boards and put them all in a folder on your browser's bookmarks bar. Then, center-clicking (with the mouse wheel) will open all the tabs at once (in Firefox or Chrome, at least). I made a screencast to demonstrate this here: http://screencast.com/t/BhjtPD2e
That second click is a mouse wheel center-click.
Answer: Another quick way to switch boards is to use the 'b' shortcut and search your boards. Press 'b' to open the boards menu in the header and the search box will be automatically focused. Just start typing the name of the board and press enter to jump to it immediately. You can use the up and down arrows to navigate the list.


What is the name of ** in python?

Question: When programming Python I sometimes do a ** to make a conversion. I understand what it does but what data structures am I manipulating? A dict and what is the other? An array? Is there a name for the ** operator?
Comment: There are two meanings for `**`.  Power and "keyword argument dictionary".  Which are you talking about?  The documentation has these words: " If the form "**identifier" is present, it is initialized to a new dictionary receiving any excess keyword arguments, defaulting to a new empty dictionary."  Which of them seem relevant to your question?
Comment: exponential operator?
Comment: "keyword argument dictionary" was the one I'm asking about. Thank you for the comments.
Answer: It's not an operator as such, so it doesn't really have a name, but it is defined as a "syntactic rule". So it should be called:

"the keyword argument unpacking syntax"

If you have a list of arguments, *args, it's called "argument unpacking", in the same manner **kwargs is called "keyword argument unpacking".
If you use it on the left hand side of an =, as in a, *middle, end = my_tuple, you'd say "tuple unpacking".
In total, there are three types of (single parameter) arguments:
def f(x)  # x: positional argument
def f(x, y=0)  # y: keyword argument
def f(x, *xs, y=0)  # y: keyword-only argument

The *args argument is called the "variable positional parameter" and **kwargs is the "variable keyword parameter".
Keyword-only arguments can't be given positionally, because a variable positional parameter will take all of the arguments you pass.
Most of this can be found in PEPs 0362 and 3102, as well as in the Control Flow section of the docs. It should be noted though that the function signature object PEP is only a draft, and the terminology might just be one person's idea. But they are good terms anyway. :)
So the * and ** arguments just unpack their respective data structures:
args = (1, 2, 3)  # usually a tuple, always an iterable[1]

f(*args) → f(1, 2, 3)

# and

kwargs = {"a": 1, "b": 2, "c": 3}  # usually a dict, always a mapping*

f(**kwargs) -> f(a=1, b=2, c=3)

[1]: Iterables are objects that implement the __iter__() method and mappings are objects that implement keys() and __getitem__(). Any object that supports this protocol will be understood by the constructors tuple() and dict(), so they can be used for unpacking arguments.
Comment: In case anyone else is confused, `def f(x, *xs, y=0): pass` is not valid Python 2.{5,6,7} syntax, nor does `def f(x, y=0, *xs):` do what you might expect. AFAIK, the only way to achieve the (obviously) intended effect is `def f(x, *xs, **kw): y=kw.get('y', 0); del kw; ...`. Python 3 handles the original syntax as expected.
Comment: While we're at it: the `begin, *middle, end = (0, 1, 2, 3, 4, 5)` syntax doesn't work in Python 2.x either.
Comment: This answer is incorrect in Python 3.5 and later.
PEP-448 specifies the ** operator as the dictionary unpacking operator. See https://www.python.org/dev/peps/pep-0448/
Answer: I don't think it has a name. In the Python Docs under "Unpacking Argument Lists", it's just referred to as "the **-operator."
I'm not sure what you mean by "the other" data structure. When you do f(**kwargs) you unpack the dictionary kwargs as a sequence of key-value pairs. I don't see that there's another structure involved.
I'll copy the example in the above documentation for clarity.
>>> def parrot(voltage, state='a stiff', action='voom'):
...     print "-- This parrot wouldn't", action,
...     print "if you put", voltage, "volts through it.",
...     print "E's", state, "!"
...
>>> d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
>>> parrot(**d)
-- This parrot wouldn't VOOM if you put four million volts through it. E's bleedin' demised !

See also: What does *args and **kwargs mean?
Comment: There are several possible ways a reader may interpret `f(**kwargs)`...
Answer: If you are unsure what to call a particular operator or if it is unnamed, you can always resort to Waka Waka Bang Splat as a reference to help you figure out what to call it. In this case for ** I would call it double-splat, though there are some alternate names for symbols.

What is the name of ** in python?


How do scientists determine the absolute or 'chronometric' date of fossils?

Question: Absolute dating is the process of determining an approximate computed age of something like a fossil. How does that work?
Comment: @Siv Thank you for your post, but can you please post your information as a proper 'answer'? Posting answers as comments is heavily discouraged because comments do not allow for the proper vetting of its content (voting, editing, ongoing improvement, etc). Thanks.
Comment: @RobertCartaino I'm sorry I don't have the time to work up a full answer, my aim was to try and nudge the question in a better direction, I would have certainly amended it to better reflect a comment, but...
Comment: related: http://earthscience.stackexchange.com/questions/2146/determining-a-rock-age-using-volcanic-ash-layer
Answer: Biostratigraphy - observing which fossils were present in which stratigraphic units, and using minimally-deformed sequences to determine age order - gives us relative ages of fossils.
Absolute ages, however, rely on geochemical chronometers: just like dating the reversals in the Earth's magnetic polarity by establishing how old the oceanic crust that records them, or working out when volcanic eruptions happened. Which chronometer you use depends on exactly what you're working with, but what they all have in common is that they use radiometric dating: the "ticking clock" is radioactive decay, which proceeds according to a radioactive isotope's half-life. Radiocarbon dating can be used for the most recent of these, but the example I'm going to use is uranium-series decay in corals - even though it's a weird one, because unlike most systems it doesn't measure parent-daughter ratios, but rather how closely the system has approached secular equilibrium.
Uranium is soluble in natural waters at conditions found on the Earth's surface; thorium, however, is not; so corals (predominantly calcium carbonate), while growing, continuously incorporate uranium but not thorium. Once they stop growing, this is no longer true - the amount of uranium incorporated in the coral is now fixed. Uranium-234 decays to give thorium-230, which is itself radioactive, with a significantly shorter half-life. At secular equilibrium, the rate of thorium-230 production (from uranium-234 decay) equals the rate of thorium-230 decay, so 230Th reaches steady state. Provided secular equilibrium has not been reached and the concentration of 238U (234U's parent) is also known, it is possible to calculate how long ago the coral stopped incorporating new uranium - became a "closed system". The mathematics of U-series secular equilibria are well understood but somewhat tedious, and are freely available.
Answer: Typically this is accomplished through radiometric dating.
While this is a complex field and the article I've provided a link for explains it better than I could here, the short answer is that different elements' isotopes decay to at a known rate, and by measuring the quantities of the isotopes in question (which are chosen depending on the approximately estimated age of the sample), the age of the sample can be calculated.
Comment: Except that you usually cannot directly date fossils. There are workarounds though.


What file type will an animated illustration come in?

Question: I am an iOS mobile app developer, and I am looking to hire someone to create an animated illustration similar to this image hosted on Dribble. My question is, what file type(s) will the graphic designer supply me with? I'm trying to plan out how I will actually embed the animation into my app. Will it be some sort of video file type like a .gif? Does it depend on the animation software they use?
Comment: I've recently learned that animations often come in JSON Lottie Files which are very lightweight and can be rendered at run-time. Does this seem to be the common file format nowadays for mobile animations?
Comment: Having a motion designer use Lottie to export the animation into something usable by you is probably the best bet. Related: [What's the best way to animate an illustration for the web?](https://graphicdesign.stackexchange.com/a/39665/23061).
Answer: Take a look at this: Creating high quality animated backgrounds from Illustrator files

The files supplied should be the ones you need, and do not depend only on the software used, but how the designer uses it.
The most reasonable option is to generate an image sequence, probably PNG if you need transparency.
Then you could use it let's say as a CSS animation, or simply be saved as an mp4 file for example. If an animated gif is ok, it should have flat colors.

But you need to define what do you need. The animation you are showing could be done in JavaScript so the only need you need from the graphic designer is the chips, and the animation itself be done by scripting, which could be your work because scripting animation is beyond most graphic designers.
The assets could also be the chips on PNG and an SVG of the path of the circuit, so you could add SVG animations to the path. Or all the chips as vectors in SVG format.
Comment: FWIW, the example shown probably doesn't need to be an image sequence. It could very likely all be SVG. If an SVG doesn't perform well, a video would be next best but only works with solid backgrounds. Worst case use a PNG image sequence.


Is it true that the soldiers returned from WW2 either didn't marry or kept themselves from families?

Question: Could anyone provide any supporting evidence to indicate that this may have been true? It would be especially helpful if this information could indicate whether this might have been due to mental and physical fatigue, or if it was attributable to other factors.
Comment: My mom, and the majority of the Baby Boomers, would probably disagree with this.  It looks like there's a spike around the end of WWI, too, if this [graph](http://en.wikipedia.org/wiki/File:US_Birth_Rates.svg) is to be trusted
Comment: I believe that this question belongs more to Cognitive sciences (http://cogsci.stackexchange.com/) than to history, because post-traumatic stress disorder is involved.
Comment: @VitalijZadneprovskij - I'd agree with that, once we've ascertained that PTSD is involved. However, the question seems to be asking *if* PTSD was involved, which seems like an OK question for here. At least one answer below is answering in the negative.
Comment: "Soldiers" or "the soldiers"? If the former, TED's answer is better. If the latter, mine.
Answer: You didn't specify a particular service or a particular country. But I am going to go ahead and say, for the most part, no.
Within three years of the end of the war, the U.S., Japan, Western Europe, Canada, and Australia had all experienced a "baby boom."
Some of this was timing: People postponed marriage and childbirth due to the weak economy in the early 1930s, and then again because of the war. They resumed when the men returned. At the same time, the younger generation got married at a higher rate and at younger ages, helped in part by strong economic conditions especially in the U.S. and benefits offered in the GI Bill. Either way, returning soldiers were clearly marrying and having families in significant numbers.
The Soviet Union and Eastern Europe did not see a boom. But they had seen population loss and displacement far worse than countries on the Western Front. Also, the Soviet Union experienced a severe famine starting in 1946. So, even if veterans were ready to settle down and raise families, things were much more uncertain. But even West Germany had a baby boom starting in the mid-1950s.
No doubt, the experience of modern warfare on the scale of the Second World War is a traumatic experience, and many returning soldiers would have had trouble adjusting to civilian life. But there doesn't seem to be evidence that the scars of war were leading them to shun marriage and procreation.
Comment: It wasn't just because of the economy, I mean, they just fought a war, which isn't really all that fun...
Answer: Not all obviously. The world is full of children and grandchildren of WWII vets (most famously perhaps the current President of the USA, who often talks about his Grandfather serving in Patton's Army in Europe).
However, it would certianly be the case that some did not. I'm unaware of any studies showing that to be more common than in non-war participants. However, if it were, I'd probably attribute the difference to Posttraumatic Stress Disorder. According to the folks at wikipedia, this condition results in a lot of behavior that wouldn't exactly make the sufferer a good social partner, such as:

decreased involvement in significant life activities
decreased capacity (down to complete inability) to feel certain feelings
an expectation that one's future will be somehow constrained in ways not normal to other people.
persistent symptoms of increased arousal not present before, such as difficulty falling or staying asleep, or problems with anger, concentration, or hypervigilance.
irritability, angry outbursts, hyper vigilance, increased startle response, and concentration or sleep problems.

Estimates for current Iraq and Afghanistan veterans have shown rates of PTSD as high as 20%. Supposedly, the likelyhood of a person getting it depends in part on how traumatic the situation they are put in is. So assuming human beings haven't changed significantly in the last 100 years, I think its fair to estimate that the rates were probably similar for WWII combat veterans if the conditions were equally intense.
The lack of treatment back then couldn't have helped much. During WWII it was still termed Shellshock, or Combat Stress Reaction (CSR). Reports were that about 4% of veterans had it, but there was a lot of stigma attached to it, so it is likely it was underreported.
I was watching a History Detectives just this morning that was tracing a WWII bomber pilot who suffered from the condition. The military historian they interviewed said that the standard treatment for it at the time was literally a couple of days off and a bottle of whiskey. (!)
Answer: This may have been true of INDIVIDUAL soldiers. But for the majority, it was the opposite.
When American "GI's" went home, they were treated like heroes. The country passed the GI Bill and Veterans' Administration just for them, to get them started in civilian life. The country was also in a celebratory mood, which included a lot of marrying and babymaking. In this context GIs were the most eligible men in the country, and the world.
A similar (if less pronounced_ thing took place among the soldiers of many Allied, especially English speaking countries. This led to a Baby Boom in much of the Western World.


How to debug crash in reference project?

Question: I have a project in which I'm taking reference of another library. I have changed something in the classes of reference project. How do i find that crash is occurring because of the changes. Gdb shows nothing when application crashes.
Answer: The simpliest way i see is testing without the changes you made, and see if the app is still crashing...
If you find out the modifications are not the source of crash, post some code, it will be better to solve your problem.


SharePoint Framework / Modern pages with ScriptLink Custom Action

Question: How to insert into a SharePoint Online site collection one script (javascript) to run on all pages, including modern pages with the new SharePoint Framework (like Script Link Custom Action, or a script tag in the master page)?
Answer: Current release of SharePoint Framework is only targeted on client side web parts. This means that there's no specific support for classic JavaScript embedding capabilities (like user custom action or JS Link). Currently available vNext experience on the document libraries, does not support these kind of customizations.
If you'd need to have still capability to inject a custom JavaScript cross your SharePoint pages, you'd have to keep on using Classic mode for the document libraries, which impacts also site contents page. Support for Classic mode can be controlled from SharePoint tenant level settings and is not going to go away anytime soon.
We are also working on providing additional extension points with SharePoint Framework, including the modern experiences for example in the document libraries. Details schedule or capabilities for these are not yet ready to be shared.
We would appreciate if you'd add a comment in the UserVoice for explaining your usage scenario for the JavaScript. This means that you'd explain the actual business scenario why the JavaScript is needed and what does it actually do. Here's UserVoice entry related on this discussion - https://sharepoint.uservoice.com/forums/329214-sites-and-collaboration/suggestions/13385364-allow-javascript-customization-and-css-branding-th
Vesa Juvonen,
Microsoft
Comment: Looking forward for these features to be implemented then finally we can recommend our customers to go to the new and better experience but not until then I am afraid.
Answer: So the single page app framework won't solve this, since the problem isn't that you want full control of one page, but rather partial control of all pages. That is in the works, but it's a bit tricky. A Couple of things pop out that need to be solved.

How do you handle classic and new pages when they both exist on a site at the same time?
How do you make them stable so that the product can improve and change over time without breaking custom solutions (we have broken people by changing innocuous properties on elements to support accessibility, but it slightly changed the dom- making the call to find element fail)
Comment: Had similar problems with a product we are working (SharePoint Online + Angular): 1. The technologies are very different from classic and new pages, so I wouldnt handle them in same way. But the classic pages can use the existing approach (page layouts / Script Link), the new modern ones just need an approach to solve the issue (to not have legacy). Eventually in a couple of years only the modern approach will exist and the problem will be gone. And if the modern approach will allow more customization points in an easier way, for sure partners will move quicker to this direction.
Comment: 2. We have a dependency injection strategy, so we define points that can be updated inside a page / site (navigation, header, footer, to small details if necessary...) and with a config file you can inject a template / controller to replace an existing one. We are doing this using require, so we define some keys for each template / controller (angular) / data source and the associated url for it and if a custom solution requires another header, will just create another header template and change this mapping. So will use our controller with their template.
Comment: 2. And when updates happen to our controllers and templates, then the interfaces will change and we mark some members as deprecated, so they will change their templates if needed. Or if the services will change, then same strategy, for a while the new and old will run side by side, so they have time to change their controllers / templates. But this allows to customize a lot from the pages / across our solution and also update easily elements (small templates, large templates...). Might be an idea to consider. But agree, should not support changes to the dom...only in templates / services...
Answer: You could create your navigation element as a separate web part and place it at the top of your page, possibly using the REACT navbar components.  However you would need to add it to every page.
This seems unfair but I believe there are good reasons why the Sharepoint team have gone down this road.
The reason that changing the actual page outside of the web part is not a good idea are:

The modern SharePoint team sites are 'Evergreen' and liable to change without notification.  Web Parts developed in the SharePoint Framework will continue to work as they if they do rely on anything outside the web part itself Microsoft will need to ensure that the changes do not affect the existing web parts.
The modern team sites are designed to be 'mobile first' but also will render on other platforms, i.e. tablet, desktop, in a sympathetic manner.  You would need to make sure that your 'custom actions' can handle all of these forms when you do not control how they are implemented.
The SharePoint workbench is not SharePoint but a cut down representation that allows you to preview and test your web parts quickly.  To use it to test your 'script link' modifications you would need to implement more of the SharePoint experience than it supports.

If you are trying to rebrand the SharePoint experience then I think you need to look at the planned Full Page / Single Page Application SharePoint Framework.  It is apparently in the product backlog and there is an entry on UserVoice asking for it as well.
Hope this is of some use to you.
Sebastian
Comment: Ok, I understand, even I don't agree. Because the main power of SharePoint was to use its functionalities and customize according to different needs. Now, it looks like it becomes a product, which has very limited possibilities to customize (a strong hit to the partners...). And the SPA framework...I don't see it as the fix for this issue. You are allowed there to use SharePoint only as a back-end...then why not using another framework (or own web service / DB) instead of paying the subscription of O365 for a glorified web service / database. Thanks for your answer!
Comment: So, what I understand from your response is there is no support to customize SharePoint experience outside of web parts? The problem I have is...I don't want to create a SPA to fully customize it (but also have to re-invent the wheel). I would like to create a normal modern "traditional" SharePoint solution (not app), which includes multiple apps and tries to solve one business problem (like an intranet for a company). But the solution would require some level of consistency through the apps / pages and if I can only customize web parts, then we lose all these possibilities.
Comment: I may be wrong but that is the gap the SPA is meant to plug.  The framework is for building web parts embedded in the OOTB experience not for changing the user experience itself.  Its the cost associated with having a stable experience.


Hyperledger fabric vs Sawtooth lake which platform is appropriate for Supply chain management?

Question: I am planning to build supply chain management system with Blockchain. I have read many blog posts related to the topic, and eventually, I get Hyperledger as a right choice for Blockchain Network. but now I have two more option in that.Hyperlegder fabric & Sawtooth lake, now I am confused about the platform so can you please suggest me which platform is better for our Domain.
Answer: There is not a definitive right answer here. Fabric and Sawtooth both designed towards a similar end goal: building a general-purpose, enterprise-level, permissioned blockchain. As a result, many of the core features are pretty similar, and there is no reason you couldn't build a supply chain on either of them.
That said, there are some reasons you might want to choose Sawtooth over Fabric in general (full disclosure, I am a Sawtooth maintainer, and might be a bit biased):

You can develop for Sawtooth in a variety of languages, including Ethereum's Solidity smart contracts (with Fabric you must develop in Go)
If you need Byzantine Fault Tolerance, Sawtooth offers PoET consensus which is hardware assisted resulting in trivial CPU usage (Fabric does not yet have any BFT solution)
I would argue that Sawtooth does a better job of isolating application logic from the core blockchain logic, making development easier
As Ferg mentioned, there is already a supply chain implementation on Sawtooth, which you could use as a starting point: https://github.com/hyperledger/sawtooth-supply-chain

As for reasons to use Fabric . . . you may find there are more external tools available. For example, Hyperledger Composer is pretty nifty, and though there has been some talk of porting it to Sawtooth, currently it only works with Fabric. That's all I can really think of, but obviously I am much more familiar with Sawtooth, so I might ask around before making a decision.
UPDATE: Sawtooth now offers PBFT consensus in addition to PoET, RAFT, and PoET-simulator. This is a BFT algorithm which does not have hardware dependencies.
Comment: @VivekSharma Correct, PoET-SGX consensus relies on Intel hardware, so it will not work with AMD machines. However, Sawtooth features a non-BFT PoET-simulator, and RAFT consensus which is BFT without hardware dependencies.
Comment: Thanks, Zac,  I am a bit late. But if I am talking about Sawtooth PoET consensus it is based on Intel's Software Guard Extensions (SGX) which is a kind of special Instructions set, so it will work on AMD or any other vendor.
Answer: Sawtooth includes an example supply chain application which may accelerate your development / evaluation process. https://github.com/hyperledger/sawtooth-supply-chain
Answer: Both Hyperledger Fabric and Hyperledger Sawtooth are permissioned distributed ledgers used for Enterprise Blockchain. Hyperledger Fabric demonstrates practical Byzantine Fault Tolerance (pBFT) based leader based distributed consensus with faster finality and block commit time compared to prominent public permissionless Blockchain platforms. Hyperledger Sawtooth provides a scalable enterprise blockchain environment for a permissioned distributed ledger. Sawtooth demonstrates Proof of Elapsed Time (PoET) consensus. As I have understood from discussions on recent implementations, Hyperledger Fabric does a good job in providing product provenance and supplychain track and trace for a limited number of nodes. When the number of nodes goes beyond 20, it seems to be having issues with respect to the performance and consistency. Hyperledger Sawtooth Lake is built with a randomized approach to consensus and a trusted execution environment. It has demonstrated good transaction throughput and finality with good security in place. It also provides interoperability with smart contracts written in solidity and ethereum virtual machine. However it is coupled with an Intel SGX based Trusted Execution Environment which could be an upfront cost for production deployments.
Comment: Thanks, Gokul, For sharing the information. have you implemented Fabric in a real-time environment in any project?
Comment: Yes Vivek. I have deployed Hyperledger Fabric 0.6 for a Diamond Trading Ledger. It was not a smooth implementation as Hyperledger was just evolving in 0.6. Now I am working with a few Sawtooth Lake related proof of concepts as well.
Comment: Thanks for reply Gokul, And it is very interesting to implement anything in the real environment. I have also started as POCs. hope your experience will help me.
Answer: To update info on the previous answer....
Hyperledger Sawtooth now supports multiple consensus algorithms...

PoET SGX ... Intel specific
PoET CFT ...without SGX
RAFT
PBFT .... Soon to be integrated


Ontario HST rebate: Do you still get the HST cheque if only one spouse has filed their taxes?

Question: What happens if one spouse has filed their taxes and the other has not? Do you still get the family HST rebate cheque?
Comment: Thank You, This really helped answer my question, I have not filed for 2008 yet. And I have some income problems right now because I am laid off. I wanted to know if I would still get back paid for the cheques I missed over the last year. I have also not recieved a GST cheque for two years.If anyone has gone through this already (reside in Ontario) Please let me know. I would like to know what I am in for.
Thanks again
Comment: @KlaneO This is a Q&A site which is a little different than a web forum.  You'll find better answers by first searching through the [hst questions](http://money.stackexchange.com/questions/tagged/hst) and if you don't find your specific question, click on "Ask Question" at the top right of the page.
Comment: @KlaneO File your late returns, and call Canada Revenue Agency.  Without your tax returns filed, CRA won't pay you these benefits (they don't know you qualify.)
Answer: I can tell that judging by the fact that the $330 was deposited today that the answer is yes.
Comment: Thanks for reporting back.  Perhaps Canada Revenue Agency based it on other information on file (T4 income, or last year's return) for the missing return ... or they just aren't as diligent as I expected they might be.
Answer: This is an interesting question.  I couldn't find definitive information on it, so your best bet for a certain answer is to call the Canada Revenue Agency at 1 877 627-6645.
However, here's my thinking on the subject:

As a couple, it's possible to receive no HST rebate benefit if family net income exceeds $166,700.  Refer to the "phase out range" in the table at this other question.
If Canada Revenue Agency only has one of the two tax returns needed for a couple, (and presumably they know they're dealing with a couple based on previous filings or the one current filing), then how are they to know if the couple qualifies or not?  The second tax return could, in theory, place the couple's combined net income over the threshold!
Therefore: I would assume that if CRA is missing half of the story, they would not send any HST transition cheque at all, since there's a chance the spouse's missing income could totally disqualify the couple from any benefits.

While that seems logical to me, I can't confirm that's how it actually works.
But there's some good news: late filers can still qualify for a benefit.  Refer to: Ontario Sales Tax Transition Benefit: Can you still get first cheque even if 2009 taxes are filed later?
Answer: I did not get mine because my husband did not file 2009 return yet.
I called and they told me it would follow aprox. 8-10 weeks after filing his return.


Combining functions - is this a case for Piecewise?

Question: I have a function $Eb1$ which was the subject of a question I asked recently - you can see it here on stack exchange. Now, in that example it's specified between a boundary $r_n$ and $r_o$ where $r_o > r_n $ and it works as expected. I also want to specify the value of the function between 0 and $r_n$ - fcor all $r < r_n $, the function is a constant with the value $Eb1(r_n)$, so the same value it is at the boundary. I am however unsure how to code this, and how to combine these two specifications into a single expression.
I was considering using piece-wise, but I am unclear about how to specify this and so far my attempts have failed. Any ideas?
Answer: I've actually managed to answer it myself - will answer here if it's any good to others;
<code>Ebound[r_] =
  Piecewise[{{Eb1[rn, 14400] /. x, r < rn}, {Eb1[r, 14400] /. x,
 r > 0}}];

Plot[Ebound[r], {r, 0, ro}, PlotRange -> Automatic]
</code>
this gives the expected behaviour;


SQL Bulk copy with referential integrity

Question: My requirement is to be able to bulk insert data to multiple table. (Having foreign key constraints)  I won't get the foreign keys till I submit the batch to the parent table. how to achieve this using bulk copy?
i cannot use linked servers or openrowset due to policy constraints.
Answer: you may be able to get away with turning off the constraints temporarily during the bulk load.


Are there ways for people with receivers to participate in contests?

Question: At the moment I only have an HF receiver (or I will when I build it, hopefully soon).  Are there any contests I can participate in, or ways for me to participate in a contest without borrowing a transmitter or working with an amateur who has one?
Answer: Summits on the Air (SOTA) is not a contest, but an ongoing activity with awards. You can participate as an activator (transmitting from summits), a chaser (working those on summits), or an SWL (listening to contacts and logging them). All the chaser awards are available to SWLs (shortwave listeners).
More info is here: http://www.sota.org.uk/Awards
Other activities also have SWL awards. There appears to be one for IOTA (Islands on the Air).
This site is dedicated to "shortwave amateur radio listening" and has a news about awards and a registry: http://swarl.org/
Answer: There is a complete list of all Amateur contests at: http://www.hornucopia.com/. Some ham contests include a category for SWLs, others don't. Check the contest's rules at this site to see if includes an SWL category.
Comment: I hesitate to call that one "complete". For example, the [Nordic Activity Contest](http://ssa.se/contest/) does not appear to be listed.
Answer: Absolutely, you can be a SWL (Short Wave Listener).
Here are some links to be a better SWL:
http://www.astrosurf.com/luxorion/qsl-cqdx.htm
Comment: Could you say more on how to be a good SWL in your answer? Answers that are just links become useless if the linked page goes away.
Answer: Most contests welcome logs from SWL especially when you are confirming the qso's and the values that are being sent.
I have (and continue) to issue ask cards for SWL-ers who confirm qso's I have made either in a contest or in normal mode.


Can we make dua to ask for the highest point in Jannah (heaven)?

Question: Can we make dua to ask for the highest point in Jannah (heaven)?
Answer: Yes.

Abu Horaira reported that the Prophet (peace be upon him) said:

'When you ask from Allah, ask Him for Al Firdaus, for it is the middle of Paradise and it is the highest place and from it the rivers of Paradise flow.' - In sahih Bukhary and Muslim
Comment: To add to your answer "**Whosoever desires (with his deeds) the reward of the Hereafter, We give him increase in his reward**, and whosoever desires the reward of this world (with his deeds), We give him thereof (what is written for him), and he has no portion in the Hereafter. (Qur'an 42:20)"
Comment: And what is the best Supplication that guarantee the highest level in Heaven?
Answer: This question could be surveyed from two different aspects:

As the initial aspect it would be said that solely praying (dua) for the highest point in Jannah won't be sufficient. Since you should have good deed to be hopeful that Allah takes you to the highest points… otherwise as a rational rule, Allah won't give us high point without having good deeds (just to say it by our tongues...)
On the other aspect, we should be hopeful regarding the promotion of
our high-point, since Allah has declared in the Holy Qur'an that "Call
upon Me; I will respond to you", consequently it indicates that pray
(dua) would be effective in granting the desires and needs that Allah
himself mentioned it. Anyhow we should be hopeful about anything
along with having good deeds.

Look at the following verse of the Holy Quran which could be related to your inquiry.

وَقَالَ رَبُّكُمُ ادْعُونِي أَسْتَجِبْ لَكُمْ ۚ إِنَّ الَّذِينَ
  يَسْتَكْبِرُونَ عَنْ عِبَادَتِي سَيَدْخُلُونَ جَهَنَّمَ دَاخِرِينَ
  ﴿٦٠
And your Lord says, "Call upon Me; I will respond to you." Indeed,
  those who disdain My worship will enter Hell [rendered] contemptible.
  (60)

Reference(s):

www.tebyan.net
http://tanzil.net
Comment: In the meanwhile, reading the following site would be beneficial for you as a related site. (in u r familiar with Farsi(persian)) : http://www.aviny.com/hadis-mozooee/ebadi/doa.aspx
Answer: yes but if you are looking for higher places you should doing some "niko"("اعمال صالح")(god things )there was group in imam ali age and they just pray an stick into mountains and..(they called soofi) and one day imam ali told that way is not true.
Islam needs doing good things like charity and some times defending against enemys and..


Deleting a package from the packaging org

Question: We have this scenario now:
We have 2 orgs :
Developer org ( where actually development takes place)
Packaging org ( where the package is created and uploaded)
We had a released version published say 2.0. We took the decision of heavily refactoring the code base of our application. In a new sandbox we then started off with a new database architecture. Now it is very difficult to move the code into the packaging org unless we delete the entire package.
Version 2.0 is installed at one customer's org. So if we decide to delete the package entirely and then move our code from the new sandbox to the packaging site and package again. How do you think this will affect the customer? Do you know of any other issues we might face?
Answer: I think you can ask salesforce to revert back changes as it was before but before doing that you must uninstall this package from every client's org where you have installed this package.


Does bitcoin improve on "hard" currencies in any way?

Question: Question is in the title. Anyone who's toyed sufficiently long enough on the foreign exchange understands that currencies are largely driven by sentiment or manipulated on the odd occasion. Plus, there's the fact that money has no intrinsic value. Has bitcoin overcome any shortfalls and risks of conventional currencies ?
Comment: When you wrote "money has no intrinsic value", did you mean fiat money, or bitcoin, or what?
Comment: Fiat money or legal tender. That's the way it's described on investopedia. The inconvenience this could cause according to my understanding is that money can lose a lot of it's value in the event of a substantial crash. Hence the interest in gold at the moment.
Comment: possible duplicate of [What are the perceived advantages of bitcoin as a store of value?](http://bitcoin.stackexchange.com/questions/2834/what-are-the-perceived-advantages-of-bitcoin-as-a-store-of-value)
Comment: This question is a pretty much a dup of my previous comment and http://bitcoin.stackexchange.com/questions/305/what-are-the-perceived-advantages-of-bitcoin-as-a-means-of-exchange
Answer: There are huge differences between FIAT and Bitcoin.
Fiat is created out of thin air "with fractional reserve banking" and other mechanisms, there is no stop on how many will be created.
Another problem is that every country is FORCED to create more of it.
Since otherwise the value of their money would increase to much, ending all export industry and tourism in that country.
So when the US prints an extreme amounts of FIAT they know that China must follow, which means that Japan must follow and the US must print more, and so it goes on.
Bitcoin can not be created out of thin air, and it takes an ever increasing energy cost to create one.
And since no country base their economy on it, its free from having to be endlessly printed. (It can´t even if it would be.)
Another very important difference is that Bitcoin is the only digital money you can own yourself with no one else having any access, and thus keep on your own computer or in your own cellphone or store on a USB the key to your money.
All other digital money, is money that is stuck in a bank and thus they might play around with it and go bankrupt.
But a Bitcoin is a Bitcoin and not simply a promise in their system.
This also means that you can send them any time of the day instantly to anyone you like now even on Facebook or in emails.
The limited amount also gives it a longterm backing in that if it picks up in any market, it cant stay this low and will have to go much much higher, a value of something like $50-$5000 would not be strange in 10-20 years IMO.
Comment: "Bitcoin can not be created out of thin air." That is not true. Please see: http://bitcoin.stackexchange.com/questions/8776/could-there-be-hyperinflation-in-bitcoin
Answer: There are some important shortfalls of traditional currency that Bitcoin addresses:

There can never be more than 21m bitcoins in existence. Bitcoin will never be vulnerable to the quantitative easing or printing of additional currency which devalues the existing funds of holders of traditional currency.
There is no central authority. A collapse of any particular corporation or govt will not cause Bitcoin to fail. There's no need to participate in a run on a bank.
Bitcoins are very difficult to steal without coercion when protected in the right way. Security features for Bitcoin are still maturing, but it is possible to encrypt a Bitcoin wallet on an offline computer and do transactions from there. This heavily reduces the change of bitcoins being stolen through malware or physical theft of hardware.
Bitcoins can be spent over the internet with very low transaction fees (a fraction of a percent compared with 3-4% with a credit card). When you know an internet retailer is trustworthy, Bitcoin is a great way to make payment.
Transactions are essentially irreversible.
Bitcoins cannot be counterfeited.

Though Bitcoin is obviously subject to manipulation through trading on exchanges, this has little effect on its usefulness as an online payment method as they can readily be converted to another currency before fluctuations have much effect.
Comment: http://xkcd.com/538/
Comment: @Lohoris, I've updated it... thanks for the feedback
Comment: Point 3 is horribly misleading, please remove it, especially since the rest of the answer is quite true.
Comment: @Lohoris, would you be happy if I reworded it to say they are "difficult to steal"? I'm not quite sure what's misleading about it, except maybe that I should add that the level of required technical computer knowledge to prevent theft is currently very high? The point I was getting at is this: someone can steal your computer, steal your wallet, burn down your house, get your bank accounts cancelled, but provided you have a copy of your encrypted wallet somewhere, you've still got your bitcoins.
Answer: Bitcoin as a currency is being inflated, currently, at a rate of 28% per year.  That alone would disqualify it as being one of the "hard" currencies (i.e., United States dollar, Euro, Swiss franc, British pound sterling, Japanese yen) for a long time to come.
Bitcoin most definitely is driven by sentiment and with the aggregate of all order books being slim, it can likely be manipulated up or down with simply a six figure budget.
Where bitcoin's primary advantage comes into play is that the currency inflation rate a year out, two years out and ten years out is already known, today.
Additionally, when trading currency there is no T+2 settlement.  Most Bitcoin exchanges settle trades instantly, and deliver bitcoin withdrawals in seconds.  Thus the funds can then be used for spending or further transfer just minutes after the trade executes.
Unfortunately, the bitcoin exchanges are not as great with the flow of fiat used for trading.  Arbitrage would keep the exchange rates about even (less trading costs) however because fiat funds don't flow cheaply or quickly in and out of the Bitcoin exchanges, exchange rates between exchanges will not be consistent.
This presents an opportunity to some, but serves as a hurdle to others. Because bitcoins are not traded yet alongside other currencies for forex or are yet considered by established financial trading firms, there are first-mover advantages being enjoyed by entrepreneurial endeavors writing custom trading bots.
One other benefit is that Bitcoin is just a protocol and data, which means it is universal.  Central banks don't need foreign exchange reserves with bitcoin nor swap agreements to trade against bitcoin.  There is simply self-interested individuals and companies doing the buying and selling (for both commerce and speculation).
Here are some other benefits:

http://bitcoinmedia.com/bulleted-advantages
Comment: The Bitcoin currency inflation rate cannot be known today. For example, currency inflation rate includes demand deposits, and there is no way you can know what the total future Bitcoin demand deposits will be at any given time. All you can know is the amount of narrow money (M0) which is not sufficient to predict currency inflation. It is quite probable that many online wallet services are already fractional reserve banks whose reserve ratios are unknown, so we already have no solid idea what the currency inflation rate is.
Comment: @DavidSchwartz, in general, I agree with your comment. However, I would argue that when you use an online wallet service using a fractional reserve system, you no longer have bitcoins. Instead, you have something more like Disney Dollars, or Bitcoin E-wallet Account Credits, which don't have the same properties as bitoins. I could say the same thing about most banks using fractional reserves when it comes to govt currencies, but at least in those cases the govt is likely to cough up when the bank goes belly up.
Comment: @HighlyIrregular: It doesn't matter whether you have bitcoins or not. What matters is whether it affects the currency inflation rate. By "Bitcoin demand deposits" I just mean demand deposits denominated in Bitcoin amounts. And actually, you've brought up another point -- if a bank goes belly up, effective currency disappears. This unpredictably *reduces* the inflation rate. (Believe it or not, all this is actually an advantage of Bitcoins. Inability for supply to adjust to demand is bad, not good.)
Comment: @DavidSchwartz, I've just asked a related question: http://bitcoin.stackexchange.com/questions/4169/how-can-i-find-out-if-an-e-wallet-service-uses-a-fractional-reserve-system
Answer: The value of money is that it makes exchanging and storing value more efficient. Your assumption that it should somehow have other value besides that is wrong.
Bitcoin improves over traditional currencies in several ways, for example:

Easy to send payments internationally without fees.
No chargebacks.
International, no need to make currency conversion.
Easy to get started with receiving bitcoins.
Possibility of microtransactions.
No inflation.
No single point of failure.
Payment is done via digital signatures rather than giving away your password.
Objective public record of payments made in case of disputes.
An option for small countries without a viable currency of their own.
No need to rely on financial institutes with poor service.
A powerful scripting language that allows more advanced transactions than "A is paying X to B", and derivatives of the technology such as Namecoin.
Privacy.
No restrictions on whom you can pay.
Comment: Thank you for detailing the differences. About value, see my comment up top.
Answer: The idea that Bitcoin is superior to government-issued fiat is based on a few myths.
Myth #1: Bitcoin cannot be created "out of thin air"
This is not true. More coins can be created if a significant number of users (either the economic majority or the majority of the mining hash power) decide that it's good for the system. Given the history of all money, it is almost guaranteed that this will happen. It is the same as government-issued paper. Remember, the US dollar was once linked to gold, and apparently could not be created out of thin air. When rules are made by humans, the rules can be changed.
A separate but related point: nothing prevents Bitcoin from being levered like fractional reserve banking. See how gold ETFs work. Gold cannot be created out of thin air (even if everyone agrees!), but you can create paper on top of it.
Myth #2: Bitcoin is decentralized and not controlled by any single authority
Again, this is not true. Bitcoin does have an informal system of governance. A few people do make decisions on behalf of everyone else. This is just like a democratically elected government, except that it isn't democratically elected (so it's a "benevolent dictatorship"). It's very much like a central bank that decides which banks are bailed out and which banks are allowed to fail (see: 2008 financial crisis), who gets to keep their money and who loses theirs.
It's easier for the miners to tax your bitcoins than it is for the government to tax your dollars (see: Cyprus depositor tax).
Myth #3: Bitcoin cannot be counterfeited
It is trivial for anyone to create an implementation of the Bitcoin design (PDF) and call it "Bitcoin." For example, you could create an alternative version of the design with a upper limit of 42 million coins instead of the current 21 million, with faster transaction processing. Incidentally, this is exactly what Litecoin does. Litecoin could just call itself "Bitcoin" and it would be legitimate, because it does follow exactly the design laid out in the Bitcoin white paper. Therefore any number of Bitcoin clones can legitimately call themselves "Bitcoin" as long as they follow the white paper (this is how it's supposed to work), and therefore in a sense there can be any amount of "counterfeit" Bitcoin currency in circulation.
If you had an agreement with someone to pay you in bitcoins for a service you provided them, and they paid you in "counterfeit" bitcoins (which are as real as yours), there would be a dispute that would have to be settled in court. This is why Bitcoin is a caveat emptor system.
On the other hand, if you paid someone in bitcoins and they claimed them as fake, you couldn't prove it, because they could legitimately claim to have expected to receive a different kind of bitcoins. In this case you would lose your money and get nothing for it in return.
Comment: I encourage the reader to think for themselves as to the reasons for my answer being downvoted. Are the above myths not myths? Is Bitcoin any different than any other government-issued fiat with respect to the above facts? Please think for yourself. Question: "Does bitcoin improve on 'hard' currencies in any way?" Answer: no.
Comment: Correct on #1 (since e-wallets could easily do fractional reserve banking, thus "creating" money out of thin air) and #2 (for the good or the bad, majority rules - even if they implement a "Robin Hood tax"). Definitely wrong on #3: there's no way in heaven or hell that I could rob you by paying in Lite/Prime/PPC/What-not-coins if you're waiting for the payment to be done in Bitcoins - the chains are waaay too different, a transaction happening in one of the alt-coins has a zero chance of being accepted at the other chains. Nil, zero, never gonna happen.
Comment: And, anyway, you're just debunking some commonly-cited-yet-untrue myths about Bitcoin and arguing thence that bitcoin doesn't improve on currencies in any way - sorry, your logic's deeply flawed. Rosenfeld's answer addresses some good points at which crypto-coins are inherently superior to traditional currencies. To counter, you could've mentioned ways in which they're inferior and then try to argument why the cons weigh more than the pros and then you would've gotten a point.


Sound volume indicator in top panel is resetting top panel upon mouse click or hover

Question: I've installed the system monitor indicator applet and weather indicator applet. all else is the same. Do you think compiz is the problem? Can I reinstall the volume indicator applet?
Answer: keep an eye on this filed bug
https://bugs.launchpad.net/ubuntu/+source/indicator-sound/+bug/883592
right now is flagged as invalid but people keeps asking so I still keep my hopes is really annoying, don't know how to debug it and been looking for a solution for weeks.. good luck


Dell Precion m6600 touch screen cursor problems

Question: I have a Dell Precision M6600 and installed Ubuntu 12.04. The cursor jumps around all by itself when I'm not even touching the keyboard. When I try to type the cursor goes crazy and clicks and jumps all over the place making it impossible to type; eventually it freezes and I can't type, click or use the key board. Any ideas on how to fix this?
Answer: I had this same problem and it took me weeks to figure out what was going on.  I thought it was an issue with the mouse, the touchpad, etc.
Finally it dawned on me -  its the stinking touchscreen (not sure why Dell decided it would be a good idea to put a touchscreen a desktop replacement laptop).
In any event, you can disable the touchscreen using xinput. I wrote the following little script that I use to turn mine off :
<code>#!/bin/bash

function showUsage() {
  echo "

  usage : $0 [-on|-off]

  "
}

TOUCHSCREEN_ID=`xinput list | grep "Touchscreen" | cut -c 55-57`
TOUCHSCREEN_ID2=`xinput list | grep "N-Trig MultiTouch" | cut -c 55-57`

TOUCHSCREEN_FLAG=`xinput list-props $TOUCHSCREEN_ID | grep "Device Enabled" | cut -c 24-`

if [ $TOUCHSCREEN_FLAG == 1 ] ; then
  TOUCHSCREEN_FLAG=0
else
  TOUCHSCREEN_FLAG=1
fi

case $1 in
  "-on") TOUCHSCREEN_FLAG=1 ;;
  "-off") TOUCHSCREEN_FLAG=0 ;;
  "--help") SHOW_USAGE=1 ;;
  "-?") SHOW_USAGE=1 ;;
esac

if [ "$SHOW_USAGE" == "1" ] ; then
  showUsage
  exit -1
fi

xinput set-prop $TOUCHSCREEN_ID "Device Enabled" $TOUCHSCREEN_FLAG
xinput set-prop $TOUCHSCREEN_ID2 "Device Enabled" $TOUCHSCREEN_FLAG
</code>
Answer: Same problem here. Dell came and replaced the touchscreen, touchpad, keyboard, motherboard, and some electronic harnesses to no avail. It's practically a new computer now! I've upgraded all the drivers and still have the problem.
One workaround is: go to Control Panel, select "N-Trig DuoSense Digitizin Settings"; on the Digitazer options tab, select "Pen Only" and click apply. This eliminates and disables the touchscreen via human touch but still active by stylus. Not sure what the real solution is, but sure hope someone figures out the real problem. It used to work nicely and now this problem which even Dell hasn't been able to fix.
Answer: Juan, do you have the nvidia graphics card?  That's what I have.  I think it's a problem with the graphics drivers.  T
he cursor goes especially crazy when the background is black or a very dark color. I've installed Ubuntu 12.04, OpenSuse 12.1 and 12.2, Fedora 17, Ubuntu Studio 12.04 thinking that one of the operating systems might solve the crazy cursor jumping promblem which it did as long as I left the nouveau drivers, As soon as I install the orginal nvidia drivers to expoit the grahics card as much as I can because I work with 3d animation, the cursor starts to go nuts again.
I tested the all the versions of the ndvidia drivers, including older versions.  It seems as though nvidia doesn't give any support whatsoever.


Rotating Objects In the Direction I want

Question:
I've been working on some weapons for my game, some of them having objects such as Crystals that will be rotating in game. I'm working on a staff which has 4 crystals, 3 at the top and 1 at the bottom. I want them each rotating in the direction that leads from the bottom vert to the top vert, meaning more of less the bottom and the top vert wont move much if any ( In the picture I selected the verts I'm referring to ). Its easy to get that to work on the crystals that are facing straight up and down, but some of the crystals extend outwards at around a 45 degree angle and thats before the weapons in the characters hand. I've probably spent 20+ hours trying to figure it out, many times I thought I was close or on the right track but always came up short. I've also created a dumbed down version of my staff and uploaded it so you can better see / understand what im referring to.
Comment: Hello, Jack Ritter. It's better you use the official .blend files uploader: https://blend-exchange.giantcowfilms.com/
Comment: Ah I was curious how the default was, couldn't find it. Thanks! Updated it.
Answer: If I understood you correctly, you should select the crystal, under the Transform tab(N) go to Rotation, change XYZ Euler to ZXY Euler. Then press R to rotate and then Z twice to get it rotating around local Z axis.

Answer: so I tried many times in Local mode to get it to rotate how I wanted. I was able to get it to work by hitting  R to rotate, then double tapping Z to get it to switch from Global to Local rotation.