Can not find WSO2(wsf.dll) file for Xampp

Question: i want to install WSO2 for XAMPP
I find this tutorial: http://wso2.com/library/3076/#link1
I download wso2 from : https://github.com/wso2/wsf
but as shown in tutorial i can not find wsf.dll file in my downloaded file ( php folder )
so the content is a bit different.
and i can not find wso2-wsf-php-bin-1.2.0-win32 to download
can anyone help me please?
Answer: That's because you can download only the source code files from https://github.com/wso2/wsf and you need to compile it, after you compiled, you will see the wsf.dll in the compile directory.
If you use linux, read README.INSTALL file
if you use windows, read README.INSTALL_WIN32


How to keep a log of execution in datastage?

Question: good afternoon
I've been searching the net how to do this but I can not find the solution:
I want to keep records of execution of each of the jobs in flat files.
Any idea how to do this??
I am using DataStage 8.5
Answer: You can do this by invoking dsjob command from the command line in unix. dsjob has a lot of options like logsum etc using which you may redirect the output to a flat file in unix. Not sure how this could be done in windows though


Can reduced density matrices of sub systems of an entangled composite system be different?

Question: In a 4-dimensional hilbert space, only 4 entangled states( normalized ) are possible ( if I am not wrong ), the bell basis. In each of the state in bell basis the reduced density matrix is $\frac{I}{2}$ for both sub systems. I assume it means both parties ( Alice and Bob, Alice has one qubit and Bob has the other qubit of the entangled state ) are equally entangled. Is it possible to have entanglement between two parties such that reduced density operators are not the same for both, meaning they are not equally entangled with each other ? I don't think it is possible for two qubit system ( I maybe wrong about it ). Is it possible for entangled states in higher dimensions ?
Comment: You're talking about the tensor product of two, one particle states, I take it? Sorry to be pedantic, but I just want to make sure you phrase your question (which is a good one) so that the maximum number of users will understand precisely.
Comment: yes my example is about tensor product of two one particle states.
Answer: There are - even after clarifications in the comments - several ways to interpret the question. So let me start out with the way that fits all parameters here:
Suppose we have a Hilbert space $\mathcal{H}$ (for qubits, $\mathcal{H}=\mathbb{C}^2$) and suppose we take a (pure) state in the Hilbert space $\mathcal{H}\otimes \mathcal{H}$.
Question 1: If we take qubits, are there only four entangled states? The answer is: Most definitely not. There are infinitely many entangled states in any dimension. Your are talking about Bell states. These are maximally entangled states, but even if we restrict your question by asking "Are there only four maximally entangled qubit states?", the answer is still "No, there are infinitely many maximally entangled states". We will see later that all maximally entangled states are connected by a unitary - and since there are infinitely many unitaries, there are infinitely many states.
Question 2: Can there be states such that the reduced density matrices are different? The answer is: Yes and no. I can easily give you an example where the reduced density matrices don't look the same, but the two matrices have to be diagonally equivalent (their eigenvalues have to be the same including multiplicities). At this point, another one of the assumptions that where not clearly stated enters: The state $|\psi\rangle$ was supposed to be pure. For mixed states, the story is completely different.
Question 3: Is this phenomenon dependent on the dimension? No, it is not. However, there is one thing I may point out, namely that if it were true in some dimension, it would most definitely be true in all higher dimensions due to the fact that you can "just not use" the other dimensions.
Below, I will write down a state $|\psi_{sasha}\rangle$ that has all the features you ask for.

Now this was all "blabla". Let me add a bit mathematics to it, but since all these questions (at least for pure states) boil down to a single observation on entangled states, I wanted to first separately answer your questions.
This is the observation we need:
Lemma: Let $\mathcal{H}$ be a $d$-dimensional Hilbert space and let $\psi \in \mathcal{H}\otimes \mathcal{H}$. We fix a maximally entangled state $|\Omega\rangle:=\frac{1}{\sqrt{d}}\sum_{i=1}^d |i\rangle|i\rangle$ where $|i\rangle$ is an orthonormal basis of the Hilbert space. Then there exists a linear map $R:\mathcal{H}\to\mathcal{H}$ such that
$$ |\psi\rangle = (1\otimes R)|\Omega\rangle $$
Proof: The idea is: We can write $|\psi\rangle=\sum_{i=1}^k \sqrt{\lambda_i} |e_i\rangle |f_i\rangle$ for some orthonormal bases $|e_i\rangle$, $|f_i\rangle$, some $k\leq n$ and some $\lambda_i\geq 0$. This is true by virtue of the Schmidt decomposition. Since for any unitary, $U\otimes U|\Omega\rangle =|\Omega\rangle$, we can suppose that $|e_i\rangle=|i\rangle$.
Then write:
$$(1\otimes R)|\Omega\rangle = \sum_{i=1}^n \frac{1}{\sqrt{d}} |i\rangle\otimes R|i\rangle \stackrel{!}{=} \sum_{i=1}^k \sqrt{\lambda_i} |i\rangle\otimes |f_i\rangle$$
When you compare the two sides, it is clear that setting $R|i\rangle:=\sqrt{\lambda_i\cdot d}|f_i\rangle$ for $i\leq k$ and $R|i\rangle=0$ for $i>k$ defines a valid linear map that proves our theorem. End of proof
This is all we need to answer your question, but for convenience, let's calculate the reduced density matrices:
Lemma: Setting as above, $|\psi\rangle=\sum_{i=1}^k \sqrt{\lambda_i}|e_i\rangle|f_i\rangle$. Then the reduced density matrices are:
$$ \rho_1(|\psi\rangle\langle \psi|)=\sum_{i=1}^k \lambda_i |e_i\rangle\langle e_i| \\
 \rho_2(|\psi\rangle\langle \psi|)=\sum_{i=1}^k \lambda_i |f_i\rangle\langle f_i| $$
I'm not going to do the proof, because it is only really easy calculations. But this immediately answers your second and third question: Can there be pure states with different reduced density matrices in dimension two or higher? The answer is "yes", since you just have to choose $|e_i\rangle\neq |f_i\rangle$ for some $i$. Now, the two reduced density matrices are in their spectral decomposition (the $e_i$ and $f_i$ are actually the eigenvectors due to the fact that they are an orthogonal basis, which means that the $\lambda_i$ are the eigenvalues), which shows you that the two matrices must always have the same eigenvalues, no matter what dimension you take!
Now let's come back to the question of whether or not there are only four maximally entangled states (or even only four entangled states). A maximally entangled state is defined by the fact that its reduced density matrices are the unit matrix. This will let us prove the following theorem:
Theorem: Setting as above. Let $|\psi\rangle\in \mathcal{H}\otimes \mathcal{H}$ be a maximally entangled state, then there is a unitary matrix $U$ such that $|\psi\rangle =(1\otimes U)|\Omega\rangle$.
Proof: The idea is simple. We know by our observation that there exists a linear map $R$ such that $|\psi\rangle=(1\otimes U)|\Omega\rangle$ and we know how the reduced operators of $|\psi\rangle$ look like via the other observation. Putting this together, we obtain:
$$ \rho_1(|\psi\rangle\langle \psi|)=\sum_{i=1}^n \frac{1}{d}|R|f_i\rangle|^2 |i\rangle\langle i| \\
 \rho_2(|\psi\rangle\langle \psi|)=\sum_{i=1}^n \frac{1}{d} R|f_i\rangle\langle f_i|R^* $$
(I recommend sitting down and writing out the details). In order for both matrices to be equal to $1/d$, you can see very quickly that the $R|f_i\rangle$ form an orthonormal basis, hence $R$ must be unitary. Conversely, for any unitary $R$, the two matrices are equal to $1/d$. End of Proof.
What about entangled states that are not maximally entangled? Well, as long as in the Schmidt decomposition, $k>1$, the state must necessarily be entangled, because it cannot be written as a product (this would be the case $k=1$).
Putting all this together, we can simply write down a state that is
a) a pure qubit x qubit state,
b) not maximally entangled but also not separable,
c) such that its reduced density matrices are not equal:
$$ |\psi_{sasha}\rangle = \sqrt{\frac{4}{9}} |0\rangle\otimes \left(\frac{1}{\sqrt{2}}(|0\rangle+|1\rangle)\right)+\frac{2}{3} |1\rangle\otimes \left(\frac{1}{\sqrt{2}}(|0\rangle-|1\rangle)\right)$$

Finally, what about mixed states? Can we get rid of the assumption that the eigenvalues must be the same?
The answer is yes. First let me note that the question of maximally entangled states is more intricate with mixed states. There is no obvious criterion. It's also a lot harder to work with, so I won't prove anything. So let's write down a state: Let $\rho_A,\rho_B \in \mathcal{B}(\mathcal{H})$ and $\rho_A\neq \rho_B$ such that they have also different eigenvalues. Then we can write down a state
$$ \rho_{sasha}=(1-p)|\psi_{sasha}\rangle \langle \psi_{sasha}|+p\rho_A\otimes \rho_B$$
As long as $p$ is small, this state should be entangled. Its reduced density matrices are given by $\rho_{1/2}=(1-p)\rho_{sasha,1/2}+p\rho_{A/B}$, and these two density matrices cannot have the same spectrum, because $\rho_{A/B}$ do not have the same spectrum.
Comment: I worked through your answer everything makes sense to me if the system is composed of two qubits.I have the following doubts: $(1)$ If I have a 3 qubit system in a pure entangled state then can two of the qubits be maximally entangled while the third is not maximally entangled with others.
Comment: (2) in your answer here http://physics.stackexchange.com/questions/170318/what-is-the-difference-between-maximally-entangled-and-maximally-mixed-states  , you define two states two be maximally entangled if their reduced density operators are maximally mixed, I can see it holds true for Bell states and thus for two qubit system, but is it true, independent of dimension of the composite system and the fact that composite system is pure/entangled ?
Comment: @sasha: (1) If you consider more than two parties, none of this works - because this here requires a bipartition of the system, so I can't talk about three qubits in this way. Because of monogamy of entanglement, multipartite entanglement (i.e. three qubits or more) is more complex. See e.g. here: http://arxiv.org/abs/quant-ph/0005115 for three qubits.
Comment: (2) Again, higher dimesions cannot mean "three qubits", it can only mean "two qudits" as in two systems with $d$ dimensions each. Then, what I wrote holds: The maximally entangled states are $|\Omega\rangle$ and $(1\otimes U)|\Omega\rangle$ for all unitary $U$. You can easily check that yourself.
Comment: @thanks for clearing my basics, was stuck on this.
Comment: Generally, $U\otimes U |\Omega\rangle \neq |\Omega\rangle$. If we take $U = [[1,1],[1,-1]]/\sqrt{2}$ and $|\Omega\rangle = 3/5 |00\rangle + 4/5 |11\rangle$, then $U\otimes U |\Omega\rangle = 7/10 (|00\rangle + |11\rangle) - 1/10 (|01\rangle + |10\rangle)$.
Comment: @EdenHarder: No. I fixed $|\Omega\rangle$ to be the maximally entangled state $|\Omega\rangle=\frac{1}{\sqrt{2}}|00\rangle+\frac{1}{\sqrt{2}}|11\rangle$ and for that state, it does indeed hold (basically, because this is a Werner state). But this is of course crucial and it might be worth pointing this out!


The impact of the Oort cloud to change the barycenter of the solar system

Question: Is the Oort cloud changing the position of the barycenter of the solar system? Does it affect in a significant way? How significant?
Answer: If the Oort cloud is included to the Solar System and the calculation, it has a potential to influence the barycenter significantly. The distance of the Oort cloud from the Sun is some 100,000 AU (plus minus a factor of two) and its total mass is around 5 times the Earth's mass.
If there were a single orbiting object at the location of the Oort cloud, its effect on the barycenter would be equal to the effect of 500,000 Earths or so (because the influence increase both with the mass and with the distance from the Sun).
However, the Oort cloud is rather uniformly distributed along an orbit or orbits that are nearly circular, anyway. So the actual effect on the barycenter is much smaller than that of 500,000 Earths.
One must realize that with the existing technology, it is very difficult to measure the position of the barycenter too accurately, anyway. By the principles of relativity and equivalence, the Sun and the planets of the Solar System are basically freely falling in the gravitational fields created by the distant objects so no local measurement can easily reveal the location. To measure how the location changes with time, one would have to measure the distance from other stars etc. very accurately, say with the accuracy of thousands of kilometers, and it's not possible now (or a foreseeable future).
Answer: The Oort cloud is a theoretical object. Its existence is more or less accepted on the basis of "comets have to come from somewhere", but no Oort cloud object has ever been observed (except for some comets that pass near us that presumably came from the cloud). It is theorized that it has two components, one disky and one spherical, both centered on the Solar System barycentre. Given the assumptions of symmetry and centering, the Oort as theorized cannot have any effect on the barycentre of the Solar System. Until such a time as it is actually observed - either directly via imaging, or indirectly via modeling of the orbits of comets - it is pure speculation to talk about an offset in the barycentre.


XOXO means "hugs and kisses" but why?

Question: What's the reasoning behind abbreviating hugs and kisses as X's and O's? Some say X is for hugs and O is for kisses, and some say the other way around; but why X and O, and why are they doubled?
Comment: Possible duplicate of [What is the origin of "xox"?](https://english.stackexchange.com/questions/1602/what-is-the-origin-of-xox)
Comment: I've always heard it as the other way around, and Wikipedia's article is contradictory on that point:
http://en.wikipedia.org/wiki/Hugs_and_kisses
Comment: In my experience 'X' for kiss is universal. I've never encountered 'O' for hug.
Comment: They're not always doubled. People often write "xo", and sometimes "xxxooo" or just "xxx". "xoxo" is just one variation on the theme.
Comment: @Colin Fine: I've never seen "O" used alone, but "X" yes, you're right. "xoxo" is very spread, though.
Comment: its weird to put it more than once. You see, people don't usually hug twice. In any case they just make the hug last longer. Same applies with kisses.
Answer: X is for kisses, and O is for hugs.
Simply, the X symbolizes the lips being in "kissing" position, and the O are the arms "hugging" seen from above.
Imagine watching 2 people hugging each other from above, you'd see 2 half-circles crossing each other, so more or less a "O".
See also this: What is the origin of "xox"?
Comment: Good answer. Just wanted to add that it really doesn't matter how many you use. More X's and O's simply mean more hugs and kisses.
Comment: Good point, +1. As to why they are doubled, is it for doubling the effect?
Comment: Yeah you're right, I've always seen it that way too.
Comment: @Mehper C. Palavuzlar: Yes, it's how @Loquacity said.
Answer: The earliest mention of X and O together dates back to the 1960s. The practice of writing X goes all the way back to Middle Ages, a time when few people were literate. People (mostly illiterate) in those ages used to sign documents using the letter X, probably because it was simple and had religious connotations (Christian cross). It was associated with 'Christ' long before that (the Wikipedia article on the letter X says that X is sometimes used as an abbreviation for 'Christ', so 'Xmas' means 'Christmas').
So by signing X, you're saying In Christ's name, I assert___. Some sources I checked say that the signee would then kiss the X to demonstrate that what was written in the document was true. This can also be confirmed at the Wikipedia article on 'Hugs and kisses'.
According to another article on Today I found, "X" first started being used as a substitute for "Christ" by religious scholars about a millennia ago, which is actually how we ultimately got Xmas as an alternative name for Christmas.
The use of X to indicate a kiss is attested since 1763. The use of O to mean a hug is believed to have arisen in North America. Etymology Nerd and Mental Floss say that it was popularised by Jewish immigrants in the United States who refused to use the cross. That article goes on to say that 'It could've been formed as a contrast to the x, or adopted because of an aesthetic similarity to what a hug looks like'.
Some other sources such as Today I Found Out also suggest that it got its meaning from resembling the arms encircling someone in a hug. Today I Found goes into great detail on the topic and says that the Jewish immigrants (illiterate) refused to use the Christian cross and used O instead to sign their letters and other documents. An article on Mashable.com adds that the letter X then transformed from a religious one to a common romantic one.
Marcel Danesi, a professor of linguistic anthropology and semiotics at the University of Toronto, in an interview with Mashable says:

"The X has always been a Christian symbol, and it is the first Greek letter in the name of 'Christ,' Danesi says. "As far as I can tell, official letters in the medieval period and even after were literally sealed with the X — sealed with a kiss of faith, I guess."
Danesi also explains that illiterate people used the X to sign documents. It was customary for them to plant a physical kiss on the X.

From Washington Post:

And in a discussion chain on the American Dialect Society, linguist Ben Zimmer, in a search of newspaper archives, found "xoxo" and "xoxoxo" used in personal ads from about 1972.

The reason why hugs and kisses is rendered XOXO and not OXOX is unknown. Maybe it because of the influence of Tic-tac-toe. However, according to ScoopWhoop, it's under debate.
Comment: I understand that X is a kiss and O a hug, it even adds an extra dimension to the game  "noughts and  crosses" but why isn't "hugs and kisses" rendered as "OXOXOX" and "XOXOXO" referred to as "kisses and hugs"?
Comment: *"So by signing X, you're saying In Christ's name, I assert___."* - Though I wouldn't say that that has never been the case, in my experience an *X* at the end of a letter has represented a kiss 100% of the time.
Comment: @BoldBen: That's a good question, but I didn't find anything else to support my answer. :(
Comment: @BoldBen: *But if X=kisses and O=hugs, why do we describe XOXO as hugs and kisses and not kisses and hugs? The debate is on.* [[ScoopWhoop](https://www.scoopwhoop.com/amp/why-does-XOXO-mean-hugs-and-kisses/)]
Comment: While it is possible that this traditional use of X, and later O, for serious purposes, is related to their more recent, relatively lighthearted use, more of an argument would be needed to convince one that it actually is. It is hard to believe that the people who started the latter use in the 1960s and 1970s gave any thought to the history that is presented here.

XOXO means "hugs and kisses" but why?


Can you let me know how you would analyze/compare this 2 box plots?

Question:
I am unsure of what these 2 box plots are telling me about the distribution of the data and how the are different. Any information will be appreciated.
Answer: Females = 0 group seems to be slightly skewed to the right (to the higher end.) No extreme points.
The Females = 1 has this funny situation that the median is also the bottom of the box. This usually is caused by too litter variation at the low end (so that your median and 25th percentile happened to be 4) or very low sample size. There are also two extreme points: id 24 is more than 1.5*inter-quartile range away from the top of the box; and id 50 is 1.5*inter-quartile range lower than the bottom of the box.
It looks like your data are whole numbers ranging form 2 to 7, I think bar plot may be a more appropriate tool to visualize them.
Answer: Box plots give us information about the center and spread of data. In a typical boxplot, the line in the box represents the median value of the data; that is, the value such that 50% of the data are above and 50% of the data are below that value. The boxes typically represent the interquartile range, or the middle 50% of the data. The "whiskers," the lines extending from the boxes, represent the top and bottom 25% of the data, excluding outliers. The individual points beyond the whiskers are outliers (or at least lie significantly beyond the range of the rest of the data).


Immersion, embedding and category theory

Question: The map between smooth manifolds $f:M \to N$ is called an immersion if the tangent map $Tf$ is injective for each $x \in M$. There is a corresponding notion of submersion. About embeddings I met two definitions: the first states that a map $f:M \to N$ is called an embedding if it is an immersion and is one-to-one: the second definition requires that the map is the embedding in the topological sense.
1. Are these definitions equivalent? If not then:
2. Which definition is correct?
3. If the first definition doesn't implies the second why it is called embedding while it would not be an embedding in the topological sense? If however these definitions are equivalent, why do we assume that the map in an immersion?
(I wonder whether is there some clever way to declare which maps $f:M \to N$ are arrows in some to be category in such a way that the monomorphism in this category will be exactly immersion and epimorphism-submersion).
Comment: The correct definition is an immersion which is a topological embedding.  I am assuming that's what you meant by the second definition but it isn't completely clear.
Comment: They are not equivalent.  The second is correct.  See Lee smooth manifolds page 156 for definition and page 157 example 7.3 for an example of an injective immersion which is not an embedding.
Comment: An easier example btw is on the wikipedia page http://en.wikipedia.org/wiki/Immersion_(mathematics)
Comment: @PVAL: A proper injective immersion is always an embedding, but not conversely.  E.g, the inclusion of an open subset into $M$ is a smooth embedding, but generally not proper.
Comment: Proper means the inverse image of each compact set is also compact?
Comment: Yes, that's right.
Comment: @truebaran I added something to my answer (from a few months ago). You might find it interesting.
Answer: The definition is a combination of the two options you give. A smooth map $f:M\to N$ is an embedding if it is an immersion, and an embedding in the topological sense.
If we omit the requirement that $f$ is an immersion, we get for example that $$f:\mathbb{R}\to\mathbb{R}^2,\quad x\mapsto(x^2,x^3)$$is an embedding. In other words, the image of $f$, which we call $c$, is a submanifold of $\mathbb{R}^2$. This is "bad" because the tangent space at the point $(0,0)$ does not behave as we want it to. The curve $c$ is a $1$ dimensional submanifold, and for $p\in c$ we expect $T_pc$ to be a $1$ dimensional subspace of $T_p\mathbb{R}^2$. However, if $\gamma:(-\epsilon,\epsilon)\to c$ is smooth as a map into $\mathbb{R}^2$ and satisfies $\gamma(0)=(0,0)$, then necessarily $\dot{\gamma}(0)=0$.
Edit, written a while after the original answer: There is another very good reason to require that an embedding will always be an immersion. Such embeddings have the following nice property:
Let $i:M\hookrightarrow N$ be an embedding of smooth manifolds, and let $f:L\to N$ be a smooth map, such that $\mathrm{Im}(f)\subset\mathrm{Im}(i)$. Then the induced function (in category of sets) $\tilde{f}:L\to M$ is a smooth map of manifolds.
If we omit the requirement that $i$ is an immersion, the above property does not necessarily hold. Note that in the category of topological spaces and continuous functions, the topology of a subspace is defined in the way that makes the corresponding property hold. When playing with smooth manifolds, we need an additional assumption which makes embeddings well-behaved.
Answer:
They are not. However, it is clear that the second one always implies the first one.
The second one is more apt, if you think about its topological implications.
The first one implies the second if the map is in addition a proper map. I don't think a lot of people call an injective immersion an embedding. (It is however a local embedding.)
Comment: Thank You, apparently the first definition which I met had a hidden assumption: the context of closed manifolds in which in this equivalent to the second.


What happens if your only pawn can't move as many spaces as required?

Question: If you have just started and you draw a move backwards 4 card, on your next turn you get a move forward 12. You have no other pawns out to move. Do you have to move The original pawn (the one you backed up 4) forward or can you refuse the move?
Answer: While you can move backwards from Start to just outside the safety zone, you can't move forward past the safety zone without going toward Home. Since a 12 is too much to land you in Home, and you can't move forward past Start, you must forfeit your turn.
Answer: Short answer: That man cannot be moved due to being too close to home and, if no other man can be moved, your turn is forfeit.
Unless the card text specifically states otherwise, you MUST perform the action indicated by the card if possible. You'll notice that all cards except 11 begin with the word MUST. The following cards have some implications with regards to this rule:

The 2 card's DRAW AGAIN happens regardless of if you could move any man.
The 7 card can only be used if you either one man that can move 7 or two men that can move a combined 7 spaces. If you have one man that's 2 spaces away from HOME and your only other man is 3 spaces away from HOME, your move is forfeit.
The 10 card must be used if you have any man not on the HOME or START spaces on the board. If no man can be moved 10 spaces forward, you are required to move one man back one space if possible.
The 11 card actually has a voluntary turn forfeit option as part of the alternate action. If none of your men can move 11 spaces forward and you do not want to exchange a margin man (a man not in your start or safety zone) with another player's margin man, you are not required to use the card.
The Sorry card is mandatory so long as any other player has a margin man and you have one man in start. Otherwise, you forfeit your turn automatically.

In the situation where your first four card draws were a 2, a 4, a 12, and a 10, the following would happen:

The 2 would start a man out and immediately give you another turn.
The 4 would move that man backwards 4 spaces, to the corner space.
Provided that man is still in the corner (the scenario outlined by Barb), the 12 WOULD BE FORFEIT because the man is 8 spaces away from HOME and no other man can move.
Provided the man is still in the corner, the 10 would move the man back one space because the man cannot be moved 10 spaces forward and all other men are on start.
Answer: When you move backwards from start, you can go into your home.  You'd need to get as many spaces or less as it is from that space to the home spot.  Otherwise you'd forfeit your turn.


Why would the front appendages be for locomotion?

Question: There are several scifi creatures that have their locomotive appendages where we have our arms and their manipulation appendages where we have our legs. Look at Star Wars for an example. Why would any creature evolve this way? I can't figure it out.
Comment: They might climb and hang a lot
Answer: Lots of possible reasons:
Since there aren't intelligent creatures to compare this arrangement to, the simplest answer is "because it's different and cool," but that's a cop-out (even if it's the true answer.) Let's come up with some possible reasons for this arrangement.

Coincidence of evolution:  Your creatures evolved from a species with hand-like appendages all round (like apes) but their ancestors resembled gorillas instead of bonobos. When evolving a stride for endurance hunting, their long-legged gait came from their existing long arms instead of their short back "feet." With time, the evolution of tool use and the minor role of their "feet" in walking meant the feet became hands and the hands became feet.
Manipulative digits close to what they need to manipulate:  Whatever this species needed to manipulate with dexterous hands was close to the ground. short "arms" close to the ground were efficient at using tools, digging, etc. At the same time, the upright stance of the creature let them be fully upright and alert to predators as they used tools close to the ground.
Super arms: The creatures use their big arm-legs for major work, like crushing lion skulls or tearing down trees. These arms are immense from being used like legs, and your creature sits or uses it's small limbs to hobble around on when using the big arms. The arms are specialized for crude tasks, and for fine skilled tasks the delicate hand-feet are used.
Endurance brachiation: Because of the way these critters move through a forest-like environment, they spend their time mostly bodily flinging themselves from tree to tree. Lots of apes can swing from vine to vine, but these guys make a full-time job of it. Their mass is well centered between their arms and the short legs are just there for an assist. There's the same justification for the legs becoming hands - they aren't being critical for motion, and are available to specialize into tool manipulators.

I'm sure there are more perfectly plausible reasons and I look forward to hearing what everyone has to say!
Comment: They evolved from flying ancestors, with the wings becoming the primary means of ground locomotion. Dougal Dixon used this in *After Man* for a creature derived from bats.
Answer: Its sensory organs are not directional.
With eyes, you need them in front to see where you are going and also what you are manipulating.  If your strongest senses encompassed the entire area about you -- perhaps you use echo location -- it might be feasible to normally walk in the direction that leaves your manipulation appendages behind and so protected from what lies ahead of you.
However, you would still need to easily walk "backwards" in order to close with things that you want to manipulate.
Answer: The Caveman Coral Crab
In addition to being an alliterative animal, the Caveman Coral Crab has evolved in a strange way to fill its niche in the environment. While its front claws have shrunk in size comparatively to most crabs, they have become stronger and more adept at grabbing a hold of the coral reefs it exclusively lives in. Using these as a means of locomotion, they can scuttle around coral like paraplegic Spidermen on a NYC skyscraper .
Whenever it is time for a meal (or a predator is nearby), the Caveman crab can pull itself in to small crevices in the coral. If all is safe, it will allow its rear most appendages to wiggle in the water like sea worms. Whenever a curious fish comes by to take a nibble, the caveman crab's intermediate legs are thrust out, one set being spear like and the others wrap around the fish and pull it in to the crevice where the meal is consumed.
I think the crab is a fun place to start since several species have developed claws and legs in many different ways. Plus, animals in water give more leniency in using appendages for differing purposes.
Comment: I can't find that crab when I searched. Do you have the species name?


3d triangle roof house model in QGIS?

Question:
Hi, I know that the is a possibility to "build" 3d structures - or rather to visualize shapefiles in 3d - in QGIS.
ie. a "reconstruction" of a redoubt I have created earlier

Alhtough I have not found a case study where a rectengular-like features where visualized.
What I am looking for is to (re)"construct" a simple 3d visualization of ALS-derived dtm interpretation of a POW camp from IWW - most of the buildings where pit-houses. To put it simply a rectengular roof sticking out of ground.

I know that it would probably be better for me to use some CAD software, but I have none experience with them and I do have GIS skills. I do not have access to ArcGIS and if possible I prefere not to use it.
Comment: What should be the output format? would a website be a soulution?
Comment: You have a raster DEM of the area and a shapefile with a height to extrude? If R is an option, it's relatively straightforward to build that scene with the rgl package.
Comment: so what You are suggesting is a model where DTM and the housing features are merged in one?
Answer: If you want to use QGIS I suggest to use this workflow:
Data needed:

DEM of the area of interest
A colada Model which represents the buildings( models can be downloaded from this website or can be created with sketchup)
A Point layer which represents the place, where the buildings used to stand
Optional: Fields on the point layer which may hold rotation, height or scale values
Optional: a base map or Orthophoto to use as overlay

Software need:

QGIS Version 2.14 or higher
QGIS2threejs Plugin
Sketchup: This might be the case if you want to be very realistic in the building of THE POW camp. You can use Sketchup (I am aware its a CAD software and op said he prefer not to use) to create the models if you dont find any suitable models in the provided links.

Workflow:

Load the data into QGIS
Deactivate every layer which you don't want to see in the final map ( for example the DEM and the points)
You will have something similar to the first image

in the QGis2threejs tool, you chose COLLADA model as object type for the point layer.(see image 2)

- as Collada file, you either choose one which is exported via Sketchup or a file downloaded.
- The values for scale and rotation I mostly use trial and error approach and use fixed values.
- As DEM use the file with the heights and use it as the DEM layer
- When clicking on run you will get a website which allows flying through the model as shown in image 3

I've tested the workflow with QGIS 2.18.12 SRTM Data and fast created Collada models

3d triangle roof house model in QGIS?


How I can subscribe to conference/seminar/workshop alerts?

Question: Can anybody please provide me link from where I can subscribe to alerts for international conferences, seminar,  workshop etc or postdoc positions ? This could be very useful for me as I generally miss important conferences/seminars/workshops.
Comment: That critically depends on your discipline and research area. Typically, there are mailing lists for almost any discipline. For the UK, you can find a lot of mailing lists here: https://www.jiscmail.ac.uk/cgi-bin/webadmin?INDEX&X=&Y=, see, for example the allstat mailing list for statistics
Answer: There are several sources I get information from:

Mailing list: See if you can find a mailing list specific to your area. Ask your advisor and colleagues about them.
Friends and colleagues in the field.
Word of mouth at other conferences: Ask participants about their favorite conferences & workshops.
Invitation emails of various kinds.
The academic sub-twitterverse
Wiki CFP: http://www.wikicfp.com/cfp/

Note that there are many conference/workshops that are not worth going to. And some of them are right out scams. I've read a number of horror stories about them (e.g. https://scholarlyoa.com/tag/predatory-conferences/). I suggest you choose carefully.
Comment: WikiCfp: Use with caution. The vast majority of listed conferences in my field is on the sketchy side.
Comment: The last link seems to have fallen to bit rot.
Comment: WikiCfp is really simple and useful
Comment: @lighthousekeeper there seems to be increasing number of hoax conferences everywhere. I no longer look at wikiCFP myself.
Answer: Just google for research conference websites you will get lot of them.
I personally use Www. edas.info it sorts all the conferences according to your need e.g area, date wise, region etc
Answer: There are plenty of such services, for instance:

http://www.allconferences.com/
https://www.conferencealert.com/
https://www.worldconferencealerts.com/
https://conferencealerts.co.in/
http://allconferencealert.net/
https://conferencenext.com/
Europe Conference

and I am sure you can find many more. I tend to be cautious with those, and trust a little more those maintained by individual, universities and academic associations. If they do not have mailing lists, you can subscribe to services of website content changes.
As for post-docs positions, they might be much less centralized.


Why do people make Shabbos early as a zchus for a sick person?

Question: Sometimes women will light candles and  accept the Shabbos a few minutes earlier than usual as a zchus for a sick person. How does accepting Shabbos early act as a zchus? How does it compare with davening for the choleh or saying Tehillim?
Comment: Regarding saying Tehillim, see: http://judaism.stackexchange.com/a/64570/8775.
Answer: The Imrei Emes is quoted as saying,

By adding more kedushah of Shabbos to the home, one increases holiness
  and purity to the family. This has the potential spiritual power to
  counteract some of the impurities that a child may have engaged in and
  bring him closer to purity. The more we widen the boundaries of
  kedushah, the more narrow the territory of tumah becomes. This is the
  power of tosefes Shabbos.
Comment: But if we are already mi'kabel Shabbos early in order to fulfill that mitzvah, does adding 10 minutes add to the mitzvah?
Comment: `The more kedusha one adds into his/her life especially on account of someone else is a great zechus` Source?


Creating a connect wallet button like JPEG.store

Question: I am creating a React app and I want to integrate a connect wallet button that can then return the users wallet address, similar to JPEG.store. What is the best way to approach this. I tried using Cardano connect with wallet https://github.com/cardano-foundation/cardano-connect-with-wallet but I cant figure out how to return the users address after they have signed in with their wallet. Any help is appreciated.
Answer: This could be solved by variety of tools:

Using Lucid, you can first enable (connect) with wallet as outlined in this simple example. Then get address via lucid.wallet.address() (it returns a Promise, so you might need to use async / await). This address is basically obtained from CIP-30's, getUsedAddresses()'s first element.
Like what you have shared in question, Mesh has a prebuilt component for it, which can be seen here. Once connected, you can get address as mentioned in this page.
Regarding library in question, can use decodeHexAddress on browser wallet api's, getUsedAddresses()'s first element.


Lemon Juice Expiration?

Question: My lemon juice went out of date almost 2 years ago. It has been in the fridge the whole time but has been opened. I'm just wondering if its safe to use? I want to put it in a cup of tea.
Answer: If you've waited that long before needing a cup of lemon tea, I'm sure you can wait until you've had time to go to the shop for a new bottle ;)
Bin it, don't risk it.
The expiry date, btw is only for unopened. Once opened it will have a significantly shorter life - checking one from the fridge here it says "Once opened, keep refrigerated & use within 4 weeks" even though the full unopened expiry date is another year away.

Lemon Juice Expiration?


How do I get legendaries at my level?

Question: I play Borderlands 2, and I dont have a legendary weapon. I heard Knuckledragger drops one, but I keep farming him on level 1, and he just drops a cheap Hornet. How do I get him to drop a Hornet of my level?  I'm at level 32.I already unlocked True Vault Hunter mode, but I was wondering if I need to farm on that mode? How do I get him to respawn? How do I get other enemies to respawn? Also, I was wondering about raid bosses. Where do I find them?
Thanks guys
Comment: What do you mean you're farming him on level 1?
Comment: possible duplicate of [Do Legendary drops only come from specific bosses?](http://gaming.stackexchange.com/questions/85837/do-legendary-drops-only-come-from-specific-bosses)
Comment: There's also the Leviathan glitch in the Captain Scarlett DLC. But you need the DLC and some people don't like using glitches and such.
Answer: You need to beat him at your level in order to get a higher level drop. On the first playthrough the areas don't scale So he'll always be level 1 and drop level 1 gear.
You need true vault-hunter mode (which will cause all their areas to re-scale starting from 30) or ultimate vault-hunter mode (where areas scale to your current level). To unlock those you have to beat the game, but once you have you can go back and forth between replay modes and you keep all your gear.
You should always farm at the highest level that you've unlocked if what you want is gear.
Raid bosses are for once you've beaten level 50. They drop the best loot, but are really intended to be a tougher challenge for UVHM and levels 50+ They are quests given out once you've cleared all the story quests in an area.
Answer: You need to kill specific bosses like Doc Mercy or The Bunker over and over again with the best weapons. You have to get the orange variant of weapons or legendary weapons.

How do I get legendaries at my level?


How can I convert a .eml file to a .mbox file for Apple Mail?

Question: How can I convert a Windows Live Mail eml file to Apple Mail mbox file
Answer: Assuming you have access to the PC with windows live mail.

Install thunderbird on the PC. This will allow you to import windows live mail, outlook express
mails etc.
Create a gmail account, with IMAP enabled. Upload your imported email from thunderbird to gmail. This should be as simple as dragging the mail over.
Point your Mail.app at gmail and download your mail.
Answer: There is a shell script and also a ruby script here - http://tinyapps.org/blog/misc/201110180700_eml2mbx.html
Ruby script did not work for me but shell script worked nicely. Both are free options.
Answer: Here is one solution I found... Here is another, and another. I thought there was a free solution, but I cannot find it.. Hope these help. I will keep looking..
Answer: Klammer will open Outlook .msg files, standard .eml files, and also winmail.dat files on your iPad. We purchased the app and took it for a spin on our iPad, testing its ability to open both eml and Outlook msg files.
It will be found at apple store.


Indentation by using AST from external program

Question: I'm pondering over doing indentation by using an AST created with an
external (non-emacs) tool. But so far I do not really know where to
start. Are there emacs packages which already did this? Any tips and hints
are welcome.
Answer: You could try to implement the LSP (language Server protocol) and use lsp-mode in conjunction with this. lsp-mode brings support for many languages already, but I'm not sure, if the LSP interface supports indentation.
Answer: There is emacs-tree-sitter, which is a package that uses tree-sitter a parser generator tool that can be use to get a AST of some supported languages.
Also emacs-tree-sitter support the option of get the AST of some languages so you can manipulate it and get some info, the documentation is interesting.
Good luck!


How to find all Ethereum nodes and list it?

Question: Hi is that possible to find eth nodes and list it with some details? I want to do some metrics and service like ether nodes. they dont have an API.
Answer: Nodes share details about themselves (see Get a peer list for my geth node), so once you discover one, if you can connect to it, you can get details about it.
In terms of actual node discovery, you can use the discovery protocol. However, you will need to make repeated queries with different targets to find all the nodes. The lower bound on queries required is the number of nodes / 16 which is not a large number for a sequential search -- however, this is if you had an oracle of some sort (you wouldn't even know you completed the search if you did exactly that number of queries otherwise). However, each node sees a different view of the network (see node table, ibid.)
My gut feeling, having not worked out the specifics and not being intimately familiar with the protocol (having just read it), is that you cannot guarantee you ever discover all nodes. The best you can do is perform many queries against many peers (which you will need to be able to connect to -- that might be challenging given the limit on number of peers that nodes have). My gut says that you can find most of the nodes in the network with a practically-bounded large number of queries.


Does current run forever in water? (assuming the supply voltage is there forever)

Question: Suppose pH of water is $6$, I think this means there is one $\text{H}^{+}$ ion for every $10^6$ water molecules.

When we plug in the battery, I believe we see a current as the $\text{H}^{+}$ ions drift to the $-ve$ side of the battery and suck the electrons injected by the negative plate of the battery. Similarly, $\text{OH}^{-}$ ions drift to the $+ve$ plate of the battery and give an electron away to the positive plate of the battery. This way $\text{H}^{+}$ and $\text{OH}^{-}$ ions neutralize themselves as they contribute to the current. Since the ions were neutralizing themselves, would the current cease to exist after some time when all the $\text{H}^+$ ions in the water were used up ?
Comment: First I think that there is an equilibrium amount of ions in water so if you remove them the equilibrium will reestablish. Nevertheless, pure water is a quite bad conductor. Second, it is not necessarily the ion that moves, while there is a certain mobility of ions, its mostly electrons "hopping" making the ion virtually move. Finally this should create a gas at the electrodes, the typical "we make Hydrogen and Oxygen" experiment, so in that sense you use up the ions by actually using up the water.
Comment: @Hiiii if the pH is not 7 initially, then it will deviate further from 7 as water is removed by electrolysis.
Comment: have a look at this http://hyperphysics.phy-astr.gsu.edu/hbase/electric/leadacid.html#c1
Comment: Hey @annav my question is not much about batteries, its about how conduction occurs at water-metal interface
Comment: Like, in metals only electrons are mobile, but in water we don't have electrons, ions move. As ions move to the opposite plates, don't we run out of them ?
Comment: You are asking "forever". The answer is that when the chemical reaction is saturated there is no "forever". the link makes clear the  atomic sizes reactions.
Comment: Sorry with forever I meant as long as the battery is alive. Should I rephrase  ?
Comment: @annav I've rephrased the question. Hope it is clear now.  Ty for looking into my question :)
Comment: Oh since the equilibrium is reestablishing, the ion concentration (pH) will remain constant ? Ahh right H2 and O2 gases are releasing out
Answer: It is energetically unfavourable to split a water molecule into the two ions $\text{H}^+$ and $\text{OH}^-$ i.e. you need to put in energy to do it. However at room temperature water molecules have a range of energies and there are always a few molecules with enough energy to ionise. So any sample of pure water at everyday temperatures always contains a few $\text{H}^+$ and $\text{OH}^-$ ions.
When you apply a voltage to your electrodes in water, you convert the $\text{H}^+$ ions to hydrogen atoms and they bubble off as $\text{H}_2$. Likewise the $\text{OH}^-$ ions are converted to water and oxygen molecules and the oxygen bubbles off. The net result is to remove water from your container.
But as fast as the ion concentration is lowered by electrolysis, the remaining water ionises again to keep it constant. So electrolysis of pure water does not affect the ion concentration. You are correct that the current will continue to flow until all the water has gone (i.e. converted to hydrogen and oxygen).
Comment: ... or until there isn't enough water to complete the circuit.
Answer: The ions are converted into gases $H_2$ and $O_2$ at the electrodes, so water is gradually being removed from the container - but it requires a very very large amount of charge to flow in order to convert all of the water into gases.
The $H^+$ ions exist as hydronium ions $H_3 O^+$. There is a reversible equilibrium in the water :
$2H_2O <=> H_3O^+ + HO^-$
The product of concentrations of the ions is fixed at a certain value which depends on the temperature of the water. If one or both types of ions are removed by electrolysis, more water molecules dissociate to keep the product of concentrations constant :
$K_w = [H_3O^+] [HO^-]$.
At 25$^{\circ}$C the product $K_w \approx 1.0 \times 10^{-14}$ when concentrations are measured in moles per litre.
In ideal conditions there will always be ions available to conduct electricity through the water. It will keep flowing until either the battery is fully depleted or the water is completely converted to gases.
In practice, an insulating layer may build up at the electrodes which prevents electrolysis from taking place. This layer is caused by other reactions at the electrodes due to impurities in the electrodes or the water.
See wikipedia articles Electrolysis of Water and Self-ionization of Water.
Comment: No, these are not the same thing. When I say *depleted* I mean *fully depleted*. The battery might be *fully* depleted before the water runs out, or the water might run out before the battery is fully depleted.
Comment: isn't the battery being depleted and water being completely converted to gas the same thing in an ideal case?
Answer: Fist of all, saying that there is one hydrogen ion for $10^6$ ions of water is wrong.ph is the negative of log of concentration of hydrogen ions. pH 6 means that there is $10^{-6}$ moles of hydrogen in a litre of the solution. Moreover, in a battery the electrolyte gets depleted not the electrodes. So, the voltage will be constant till the electrolyte can provide the potential ideally.
In reality, the voltage curve drops at the end of the life of the battery.
Comment: Did you mean battery?In that case, the ions will flow into the solution or away from it till both the solutions have the same voltage difference and then the current will stop(just like connecting two opposite batteries).
Comment: @DavePhD The redox reaction reduces one electrode and oxidizes other.The inherent potential is drawn from the electrolyte. The lead acid battery you mentioned can even be reversed ,i.e. charged back if electricity is given the other way.For a very short and concise description,visit  http://sciencing.com/do-batteries-go-flat-7787904.html
Comment: Okay so its a molar volume, got it! Thank you :) May I ask how the charge flows outside the battery, on the other side at metal-water interface ?
Comment: That's the place where you want to use it.For example, you can connect a resistor (maybe a small fan) to it and current will flow through it .
Comment: @ Rishabh Jain I think my question is not so clear; Actually in my question, I'm connecting the battery across water. Water is the load resistor in my setup. I'd like to know how charged ions move in water w/o getting used up
Comment: @RishabhJain I think you have it backward when you say "in a battery the electrolyte gets depleted not the electrodes".  For example a lead electrode is depleted while the sulfuric acid electrolyte is not.  https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery
Comment: @RishabhJain Yes, that one can be reversed.  Zinc electrode is depleted in a primary battery  https://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery


disable option + delete/left_arrow/right_arrow key combos on remote linux ssh

Question: How do I disable option + delete/->/<- key combos when ssh into a remote linux box from my MacBook? Alternatively, map option + delete to the same function as command.+ delete. Currently I get [D, [C, etc on the screen, which is quite annoying. Thanks!
Comment: For the next down voter, could you suggest a better forum to ask this question? I will close it immediately and migrate over. Thanks!
Answer: I found a comprehensive answer here, in particular the natural text editing setting.
In summary:

Go to Preferences... > Profiles > Keys
Press Load Preset...
Select Natural Text Editing

Then, you can move a word backwards using Option ⌥ +
  ← and a word forwards using Option ⌥ +
  →. Also you can delete a word backwards using  Option
  ⌥ + ⌫, delete the whole line using Command
  ⌘ + ⌫, and more.


How to eject all drives from the command-line

Question: I want to eject all hard drives with a command on the Terminal instead of going to the Finder and pressing eject on each drive. How can I do it?
Answer: You can use the in-built AppleScript solution, as mentioned in this thread and this page, by adding this to ~/.bash_profile:
alias ejectall='osascript -e "tell application \"Finder\" to eject (every disk whose ejectable is true)"'

This will require you giving permission to Terminal to control Finder, or you will get this error:
execution error: Not authorised to send Apple events to Finder. (-1743)

If you want a pure bash solution, here is a function that you can call with ejectall. If you renamed your startup disk or have different Time Machine backups, you may need to edit the condition that filters out the drives.
ejectall() {
    total=0
    ejected=0

    for v in /Volumes/*; do
    if [[ $v != *"Macintosh HD" && $v != *"com.apple.TimeMachine"* ]]; then
        echo "Ejecting $v..."
        diskutil eject "$v" # The command to eject the volume

        if [ $? -eq 0 ]; then
        ejected=$(($ejected + 1))
        fi
        total=$(($total + 1))
    fi
    done

    if [ $total -eq 0 ]; then
    echo "No drives to eject"
    else
    msg="$ejected drive(s) ejected"
    failed=$(($total - $ejected))
    if [ $failed -gt 0 ]; then
        msg="$msg, $failed drive(s) failed to eject"
    fi
    echo $msg
    fi
}

Both methods will also work for CDs.
Comment: Very nice - I would like to see also a one-liner for `mountall` - presumably it would have to use diskutil ?
Comment: @PaulR Yes, I see now. I checked that `diskutil` lists the unejected drive, so yes, one can write a similar `mountall` script. How about writing a new question, tag me and I'll answer it?
Comment: @PaulR I don't know as I don't have that problem on `macOS`. I plug a drive and it mounts.
Comment: Yes, but there are times when you want to temporarily unmount a disk, so you don't necessarily unplug it, but then afterwards you need to mount it again. Of course you can unplug it and then plug it back in again, but a simple command would save you the effort and reduce wear and tear on your connectors.
Comment: Good idea: https://apple.stackexchange.com/q/458990/527
Answer: Use diskutil.
You can list the current devices with diskutil list, and use diskutil eject device-name to eject a device just like from Finder.
This will go a step further than just using umount by, for example, disconnect a USB device so it /dev/disk node disappears.
See man diskutil for more details.
Comment: Yes, I'd been using `diskutil`, with the disadvantage of ejecting drives one by one and remembering their names.
Comment: It will spin down the drive too
Answer: I've recently started learning shell scripting so I tried an answer to this as an exercise.
Script uses diskutil list external to get all external disks then loops over the output to unmount them.
I then created an alias in ~/.zshrc so I now only have to type eject in Terminal to eject all external disks attached to my Mac.
(thanks to @nohillside for the tweaks)
#!/bin/sh

#script to eject all external drives
disks=$(diskutil list external | sed -n '/[Ss]cheme/s/.*B *//p')

if [ "$disks" ]
then
echo "$disks" | while read line ; do
    diskutil unmountDisk /dev/$line
  done
else
  echo "No external disks to eject"
fi

Answer: umount has an option to unmount all file systems besides the main one.
sudo umount -A

You can also force this in case files are still busy/locked (with the risk of data loss) by running
sudo umount -A -f

Comment: Nice one, with the benefit of one-line at the cost of a `sudo`. +1 for ejecting drives that are still busy.
Comment: I tried this command twice and on both occasions it caused my macOS computer to hang, with the last line in the terminal saying `Saving session...`.
Comment: @miguelmorin That's a message from Terminal when you terminate the shell running within a tab. I don't see how it relates to unmounting all the drives besides the main drive unless your home folder (or any other file referenced by the shell) is stored on one of the unmounted drives.
Comment: I don't have the home folder in the unmounted drives. I don't think I have files referenced by the shell there either because they serve for Time Machine backups or a data drive for videos, and I can launch Terminal when they are not connected.


Does the 'Civil War: Deluxe Collection' contain all the "Civil War" books?

Question: Does the 'Civil War: Deluxe Collection' contain all the "Civil War" books? Or do I still need to buy more books after getting this one?
.
Answer: I'm assuming you are talking about this book since you initially said Marvel's Civil War graphic novel. If that is the book you are referencing, then it contains all issues, #1-7, of the Marvel Civil War Comic Event.  There are however various comics that tie into the story line and a sequel series, Marvel Civil War II.
All that being said, I own a copy of the book I linked and it seemed to me to be a complete story in itself.


Are there any video tutorials available for game programming with Max?

Question: Are there any videos on how to make a small game using Max? I mean is it only done in Max or are there other things used? I am a newbie in game programming.
Answer: 3DS Max is a 3D modelling tool. There are several video tutorials available all over the internet (of varying quality). However, you can't make a game just using Max -- all it does is modelling and rendering. You'll need to use something else entirely, or at least something else in conjunction with Max, in order to make a game.
Blender is a similar kind of modelling tool that does have a built-in game engine that can be used. It's also much cheaper than Max (because it's free). There's lots of documentation and educational material on Blender's website and elsewhere on the internet. You may also want to consider looking at Unity. There are several other game construction tools available as well.
You could also teach yourself to program -- I'd recommend Python as a first language, if you choose to do this. This will give you a lot of control and flexibility in the games you create, but it will involve a much steeper learning curve (for example if you choose to go this route you'll likely be learning to develop very simple text-based games for some time before you are ready to tackle the complexity of 3D graphics and loading 3D models and scenes exported from Max).
Comment: The UI for Blender is garbage, though
Answer: As the other two people have said, you cannot make a game in Max. If you are a designer/artist and you wanna get into game development there are a couple of tools available online that you might like to consider picking up:
1) Construct: http://www.scirra.com/construct/
This is an open source (free) game development tool targeted specifically for 2D games. It's also targeted at people like you who aren't programmers because you don't need to learn programming to use it. The interface allows you to build a game without writing any code
2) Game Maker: http://www.yoyogames.com/gamemaker/
Basically a similar thing to Construct. It has a free version as well as a pro version. Also doesn't require programming
3) Game Salad: http://gamesalad.com/
Another similar thing, except this one is Mac only.
Now these three are great if all you want to do is mess around with game development, have some fun and all, but if you're serious in getting into some real game development, unfortunately you MUST learn programming. That's not to say you need to be amazing at it, but you do need to know it relatively well. And the tool I very very much recommend you use if you want to get into it is called Unity3d: http://www.unity3d.com
Unity is a free game development tool that is very popular nowadays amongst indie developers. Its interface is very well made. Basically if you want to get into serious game development - it doesn't get any easier then Unity. You do need to write code to get stuff to happen in Unity, but in my opinion it's very easy to learn. The language you will be using in Unity is Javascript, C# or Boo. I recommend Javascript
The final option is.. don't develop games. If you want to stay in 3DSMax, go ahead and become amazing at it, then you can make content for games such as 3D models, animations, textures, etc.
Hope this helps
Comment: suppose i made a moving ball animation in 3ds max , is it possible to add some mouse click function on that ball
Comment: Not that I know of.. I'm not a 3DS user myself (I'm a maya user). You might be able to get some kind of interactivity happening if you were to delve into Max scripting, which is basically programming - and if you were gonna do that then you may as well leave 3dsmax for something that actually offers interactivity as a focus. If you for some reason MUST do it in 3dsmax then maybe this could help http://www.eonreality.com/raptor/
Answer: 3ds Max is not used for programming games. It is frequently used in game development, but the relevance of 3ds Max to game development is that you can create 3D models using it and then export them to load in a game engine.


Is cosmological expansion caused by dark energy?

Question: People hear about dark energy, conceptualize it as a kind of universal repulsion of space itself, and then tend to say that cosmological expansion must be caused by dark energy. Is this correct?
Comment: related: https://physics.stackexchange.com/questions/26269/why-do-we-need-the-concept-of-dark-energy-to-explain-the-expansion-of-the-univer
Comment: and [Why does dark energy produce positive space-time curvature?](https://physics.stackexchange.com/q/96551/84967).
Answer: No. Dark energy is not needed in order to explain the expansion of the universe, only to explain why it's accelerating. The successful description of cosmological expansion in terms of big bang models dates back to about 1930, while the effects of dark energy were not observed empirically until around 1998.
Although general relativity does not describe motion in exactly the same way as Newtonian mechanics, the basic insight of Galileo and Newton still applies. Motion tends to continue on its own. In older models of cosmological expansion without dark energy, the expansion of the universe simply continues because of its own momentum, but would have decelerated because of gravity.
Even in newer models that include dark energy, the effect of dark energy is only relevant at fairly late times. Its effects were completely negligible in the early universe.
Answer: The cosmological expansion of the universe from the initial big bang is mathematically modelled by the Freedman-Lemaitre-Robertson-Walker equations, which are a solution to the Einstein's field equations (which represents a mathematical description of the gravity, and predicted the space-time curvature). There is not dark energy in that models, which are a correct description of the expansion of the universe until a "more recent epoch" ($z \sim 0.5$). Later in the history of the universe an acceleration was inferred from a detailed study of the light curves of type Ia supernovae.
We still don't know what the dark energy is, but the Einstein's equations plus the cosmological constant term leads to a good approach.


Pannier rack restricting dérailleur movements

Question: I fitted a pannier rack to my bike and the placement of it caused the rear derailluer cable and housing to be pushed outwards slightly, increasing the tension in the cable, I guess. The derailleur will move between 7 of 8 gears however the cable is now too taught to get the derailleur moving to the biggest gear. It is also tough to get the derailleur moving between gears without skipping them. I've tried replacing the gear cable only. The cable housing has remained the same length. Would increasing the cable housing length help or is this simply a case of the pannier being incompatible with my bike?
Comment: A picture would really help here, but it sound like the cable is caught on the rack -- maybe you need to route inside rather than outside, or maybe you need to cut a bit off your rack (I've seen strap attachment points in odd places getting in the way).  It might not be the tension as such, but that the cable+housing combination is rather stiff and won't move/bend sideways enough to reach all the gears.
Comment: I'm not at home just now but I've mocked up what the pannier is doing to the cable. The red lines are the pannier rack and they should be behind the cable in the picture. The arrows indicate which way the cable is being pushed by the rack. https://imgur.com/Tnpf0jT

I didn't realise the housing moved when changing gears but if it needs to move towards the bike at all then the rack would be preventing it from doing so.
Comment: Basically if the rack attachment caused the cable to be overtighten, you first should extend the housing. Replacing the cable only should not help. But as @ChrisH wrote, try to route it inside the rack.
Answer: I would concur that the solution here is to increase the length of the cable housing that is inferring with the rack. If the rack is putting any pressure on the cable housing, then it will interfere with the ability of the derailleur to shift properly. Depending on how much free cable is left over coming out of the derailleur, You will most likely need to also replace the cable with a new one that is longer.  But this shouldn't cost any more than $10~$20 from the local bike mechanic at the back of your favorite bike shop.
Comment: Most people should have enough excess cable beyond the bolt to do this with just a small longer section of cable housing.


Get profile name from User without Query

Question: I want to check Profile Name of Users inside a for loop so I need their profile names without querying in apex is there any workaround this.
Answer: Another alternate way would be to use Platform Cache. Using this you can store the details of profile using Map<Id,Profile> which will map profileId with their Profile. And whenever you want to get the name of profile for any user then simply use map.get(UserInfo.getProfileId()) method to get the profile name.
Using platform cache what you can do is query all the profiles at once and then simply use it any Apex class. There is another alternative to use custom settings but that's not a feasible approach.
Sample Example:
Map<Id,Profile> profileMap = [SELECT Id,Name FROM Profile LIMIT 100];
Cache.Org.put('light002.partition1.profileList', profileMap);
if (Cache.Org.contains('light002.partition1.profileMap')) {
    String profileName = profileMap.get(UserInfo.getProfileId()).Name;
}

Comment: I haven't used this feature so I would like to know if this will work during execution of batch jobs as there will be multiple users how can I make sure that correct profile name coincides with correct user.
Comment: @Ishan I've mentioned a link of platform cache in my answer. You can go through it. Let me give you highlight of my answer. In the code sample, I've created a `Map`. This will have all profiles mapped with their id's. You just need to get profile by passing profileId of current user using `map.get(UserInfo.getProfileId())`. Platform cache is a great feature provided by salesforce to store the data like we do using session storage, browser cache and cookies. However in this you can retrieve cache data in your apex class.
Answer: If you don't want to burn a SOQL Statement and you're working with an SObject, you can use this approach:

Formula field (named, say, "CurrentUserProfile) on an object  that has this code:
$UserProfile.Name
In your trigger, you can refer to the variable;
for(Object__c obj :triggerNew) {
   System.debug('Current User Profile: ' + obj.CurrentuserProfile__c);
}
Comment: I am using this method currently but will like to see if there are any other solutions to the problem as client may not agree with a additional field.
Comment: I ended up following this method as it is more reliable and better than using system cache.
Comment: I think this is the optimum method.
Comment: I would consider this bad system design.  You're basically creating a field on an object that holds data irrelevant to what the object represents.  I'd burn a soql query to get the name if you really need it.
Answer: Once you have a session you can call getUserInfo(). In the getUserInfoResult() there is the profileID in the response.
Now that you have the profileId you can send a SOQL query off to Profile to get the Name field.
select id, name from profile where Id = '00e30000000hDW1AAM'
When performing a SOQL query against Opportunity you can get the last modified user name with LastModifiedBy.Name. E.g.
Select Id, Name, LastModifiedBy.Id, LastModifiedById, LastModifiedBy.Name From Opportunity.
Unless you are already sending a query to something like the User object you won't be able to get the Profile name without an additional query. You can use the userInfo from the LoginResult to save one API query. However, at some point you are going to need a query to go from the ProfileId to the Profile.Name
Comment: Actually, I am inserting user in bulk and assigning some custom Id based on profile so I don't want to do a query.


Connect my salesforce instance to Xero using xero public application

Question: I am trying to connect my salesforce instance to Xero. For now, I successfully connect my salesforce instance to xero using private application. But what I want at the moment is to connect to xero using public application. Does anyone of you has an idea about this? Or any good article to connect salesforce to xero instance using xero public application?
Comment: Have you checked out the integration apps available on the Salesforce  app exchange https://appexchange.salesforce.com, rather than going the bespoke route? One that I've used successfully in the past which integrates with xero is Breadwinner -  https://appexchange.salesforce.com/listingDetail?listingId=a0N3000000B4dkKEAR. It was easy to use and setup and allows two-way sync of invoices with clicks not code.
Comment: Breadwinner is a good one: https://appexchange.salesforce.com/listingDetail?listingId=a0N3000000B4dkKEAR
Comment: yeah I even installed breadwinner. How breadwinner do the integration is the thing I want to accomplished. I just want to create my own.
Comment: @Hope - That question is the definition of "Too Broad". There is a reason many of these packages have been created. I would bet they have put thousands of hours into tuning it, coding of edge cases, coding for customer requirements, etc. Do you have that kinda of time? If so, better fire up your apex skills and get coding. When you have a specific question feel free to post it up. You did state you wanted a public application. Are we misunderstanding what you men using private and public in the way you did
Comment: @Eric yeah sorry for that. What i just want to know is that, if there is any good article or SDK I can use to start building what I want. For now, I already successfully connect to Xero using xero private application wherein, I need to create a salesforce certificate and upload it to xero to get the consumer key and other thing. Public application works different, it is quite user friendly wherein you automatically connect to xero by supplying your xero and username password as what is commonly happen to third party application.
Answer: The Xero documentation does appear to be quite light on information on how to go about this, but it appears that they just use the OAuth 1.0 standard.
You'll have to follow the setup steps in the documentation to setup an application, and then develop a combination of Apex and Visualforce/Lightning to provide the user with a button that opens up the authentication URL for Xero.
Rough Process
It's been a while since I went through this, so this may not be 100% correct, but the gist of the process is the following:
First you'll have to get an unauthorized request token using a callout from Apex, then redirect the user to the authentication url using the token as a parameter. You'll then have to implement an Apex webservice that can be used for the callback url to know when the request token has been authorized.
Once that happens you can swap the request token for an access token which can then be used when making requests to their API.
Possible Alternative
Depending on your use case, you might find that you can use Named Credentials but I think they only support OAuth 2.0 so that might be a non-starter. If you only need to use one Xero user for all the integration work then using the named principal option in these could make life a lot easier for you.
Answer: Breadwinner here! Happy to help if we can.
You said you want to do a Public application, but I'd suggest you consider a Private Application if you want to mimic our functionality.
As you can see here, https://developer.xero.com/documentation/getting-started/api-application-types/, there are in fact three types of applications. We're a Partner application (also known as Public Partner), which gives us long term access. We need that to run our hourly update to pull data from Xero
A traditional Public app requires constant verification, as the token expires after 30 minutes. If you want your sync to run in the background, or have it go through a specific Xero user regardless of who is attempting this in Salesforce, a Public app will be problematic. You'll constantly have to have people signing in to Xero and they will need the correct authentication (usually, Xero Admin is required).
So, if you want something to run in the middle of the night, or be used by people without Xero Admin rights, then I'd opt for a Private Application. Once established, a Private Application can maintain that connection forever.
@Hope - the user friendliness of the Public application is, in my mind, completely negated for apps that require background syncing. Public Apps are better for occasional use connections.
This article explains how to create a Private App. https://developer.xero.com/documentation/getting-started/private-applications/
One tip - the expiration date of your public-private key pair is set by you. So something in the year 2150 is a pretty safe bet :-)
Also, this step can be a bit tricky. We used a Private model initially in our app and this was something that one of our developers just couldn't solve after two days. We gave it to another developer and they got it working in a day or so. Other people seem to struggle with this step, judging by the threads on Stack Exchange.
As for @Eric's comment, yes, you're completely right! In fact, "thousands of hours" is just the start. We don't track developer time that closely, but I'd estimate somewhere on the order of 16 developer years have gone into our integration.
One more general bit of advice - be aware that Xero has a hard limit of 1000 API calls a day, Salesforce has a 3mb upper limit for REST calls, and Salesforce can generally only do 10 REST calls in a batch. So even if you connect successfully, it's a very difficult juggling act to get everything without hitting limits. You might think this is solved if you use the Xero Paging API, but that's only available for Invoices, not for Credit Notes. And, with more than 1000 invoices you're above the Salesforce 10-per-batch-limit. So you'll have to communicate with Xero using both the Paging and Non-Paging API. One way to solve this is to build out middleware that work around these various limits.
Comment: Very well said. I really appreciate it ++.


Text box won't expand

Question: Adobe Illustrator - All of a sudden my text bounding box appeared without anchors so I can't expand it, instead it wants to link to other boxes. Never happened before - any ideas? It's likely I accidentally pressed a combination of buttons but all the other docs I have opened from the past or anything new I try has the name problem
Answer:
Go to 'View → Show Bounding Box'
or hit Ctrl+Shift+B

Text box won't expand


Transfer of wordpress site from one domain and server to another domain and server

Question: I have moved a wordpress site from one domain and server to another domain and server. Everything looks fine except all the links within the site are still pointing to the previous domain. Please let me know what went wrong with the transfer. I'll really be thankful for the kind response and help.
Answer: Most probably, nothing went wrong, you just have to set some things to the new server.
Firstly, there are the home and site urls (to be found in the general settings).
Then, possible absolute links pointing to the old domain have to be adapted.
To change these links, you have to adapt the SQL table.
Update options (this can also be done via the general settings, as described above):
UPDATE wp_options
SET option_value = replace(option_value, 'http://old-domain.com', 'http://new-domain.com')
WHERE option_name = 'home' OR option_name = 'siteurl';

Update absolute links inside posts:
UPDATE wp_posts
SET post_content = replace(post_content, 'http://old-domain.com', 'http://new-domain.com');

Comment: +1 though I would recommend [Velvet Blues Update URLs](http://wordpress.org/extend/plugins/velvet-blues-update-urls/) to sort out the absolute links.
Comment: Ah, I didn't know about that plugin, though I was sure there **is** one for this particular task. Thanks.
Comment: I am not affiliated at all with that plugin but it is one of the very, very few I use, much less recommend.
Answer: You probably need to log into the admin portal (www.yoursite.com/wp-admin) and change the site's address under settings >> general >> wordpress address.
Hope that helps


Magento 1 - How to trigger the password reset email to customer , instead of an email with an auto-generated password?

Question: Magento 1 - How to trigger the password reset email to customer , instead of an email with an auto-generated password ?
Answer: Here we are trying to (trigger/send) the password reset email to customer.
Instead an email with an auto-generated password.
We can achieve this functionality by following the steps below :-
We will create a checkbox field (Send forgot password email) in customer information section
same as "send autogenerated password" and when CS
checks that box and saves the customer information
we will be using "adminhtml_customer_save_before" event
that triggers on customer save before from customer information section backend
"doBeforeSave()" method is listening on this event
here we will get the (customer id , email) , we will check field "Send forgot password email" checkbox value if its set then we will use this code
ref - https://stackoverflow.com/questions/27920153/create-and-send-email-to-customer-reset-password-link-programmatically-in-magent,
to send the reset password link email to the customer.


Challenging problems in calculus

Question: I'm looking for a textbook (or website etc.) which contains challenging problems in calculus. Problem in Real Analysis by Titu Andreescu is good, but slightly too advanced for me. Spivak's Calculus is very good, but I need more. Can anyone give me any references?
Comment: Related: http://math.stackexchange.com/questions/9958/interesting-calculus-problems-of-medium-difficulty
Comment: Spivak's text must have more than 1000 problems, most of which are indeed challenging.  You say you like these problems but "need more".  Could you explain why you need more than 1000 problems?
Comment: In [this question](http://math.stackexchange.com/questions/63504/suggest-textbook-on-calculus) the poster also asked about challenging exercises in calculus.
Answer: There is a problem book:

Problems in Calculus of One Variable by I.A. Maron

You can always see the entrance question papers of the IIT - JEE exam. They do contain challenging calculus problems.
Answer: The Harvard-MIT Math Tournaments always feature some interesting calculus problems.  Both problems and solutions from previous contests are archived.
Answer: If you haven't already considered it (it's a well-known classic), I suggest looking at
Introduction to Calculus and Analysis by Richard Courant and Fritz John.
http://www.amazon.com/dp/354065058X
Answer: I'll be dating myself with this answer, but I always found the miscellaneous problems at the end of some of the chapters of Thomas (3rd) to be a good source of challenges. I'd also consider looking in Apostol's Calculus.
Answer: The Art of Problem Solving has textbooks for middle school through calculus.  The description for the calculus book includes:

The book includes hundreds of problems, ranging from routine exercises to extremely challenging problems drawn from major mathematics competitions such as the Putnam Competition and the Harvard-MIT Math Tournament. Many of the problems have full, detailed solutions in the text, and the rest have full solutions in the accompanying Solutions Manual.

It's relatively inexpensive and you can get a full solutions manual, which is also relatively inexpensive.  This is a full textbook for single variable calculus.
http://www.artofproblemsolving.com/Store/viewitem.php?item=calculus
The point of these Art of Problem Solving books is that you learn problem solving and not just the basic rules/techniques.
Answer: I also suggest the AOPS Calculus book.  The problems are challenging, but they often have hints you can choose to look up, and clear solutions in a separate book.  Very informative.  My Calc professor had us buy it instead of a regular college textbook, and it's been much more challenging, but much more rewarding, too.

Challenging problems in calculus


Minimal CORS mail PHP

Question: I have an PHP endpoint used to mail me feedback or error logs from my sites here: https://github.com/kaihendry/vanilla-php-feedback-form/blob/master/feedback/feedback.php
<?php
switch ($_SERVER['HTTP_ORIGIN']) {
    case "https://example.com":
        header("Access-Control-Allow-Origin: " . $_SERVER['HTTP_ORIGIN']);
        break;
    default:
        die("Bad origin: " . $_SERVER['HTTP_ORIGIN']);
}
// Access-Control headers are received during OPTIONS requests
if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {
    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
        header("Access-Control-Allow-Methods: GET, POST, OPTIONS");
    if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
        header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");
    exit;
}
$subject = 'Feedback from ' . $_SERVER['REMOTE_ADDR'] . ' ' . $_SERVER['HTTP_REFERER'];
$input = json_decode(file_get_contents('php://input'), true);
if(empty($input["msg"])) { http_response_code(400); die(); }
$message = json_encode($input, JSON_PRETTY_PRINT) . "\n\n--\n" . json_encode($_SERVER, JSON_PRETTY_PRINT);
if(empty($input["from"]) || !filter_var($input["from"], FILTER_VALIDATE_EMAIL)) {
    mail('firstname.lastname@example.com', $subject, $message);
} else {
    $headers = 'From: ' . $input["from"];
    mail('firstname.lastname@example.com', $subject, $message, $headers);
}
?>

There are a couple of problems:

It's slow. I suspect it's mail(), which is used with ssmtp & AWS SES. It's fast when I comment the mail line out. Can it be backgrounded somehow?
Should I be returning JSON like status OK or not OK if mail() fails? What is best practice?
Is there an easy way of compiling them into a digest or maybe better alternatives to email I may have missed? I'm a bit worried someone can abuse this script using cURL. How can I prevent that sanely?
Comment: my 2 cents:
If you plan using json messenging make sure your file are saved with UTF8 without BOM character mode. Short story is; OK is not the same as say OK%20
Comment: updated my answer with 2 and 3
Comment: bountyyyyyyy :)
Answer: 1
From looking on the script, seems there is nothing that can be slow except of the mail(). The problem is, it needs to connect with the target mail server and thats often very slow.
mail() got many problems so it is best avoid using it. You can read about it here and here
The best alternative is probably Swiftmailer http://swiftmailer.org/. With that  you can solve also your "in background sending" using spool. Your mails will be send after the script finished running.
For the next two questions I would advise to handle your script like an HTTP API.
2
With Spool
you cannot know in real time if sending of your email was an success, as this will happen after your script will terminate.
Without Spool
it could still be faster (or not), but you will know if it was ok right away
What to return depend now on the above
You can use standard response codes, almost for all your scenarios. http_status_codes
You don't need to return anything in the body most of the time.
Fail:

400 - Bad Request - when the request is missing $msg, or body json is malformed
401 - Unauthorized - when missing http_origin or not in the list of allowed
405 - Method not allowed - if it is not POST or OPTIONS
409 - Conflict - email sending failed (if not usign spool)

Success:

200 - OK - email send successfully (if not using spool)
202 - Accepted - when everything is ok, but using spool so you don't know if the sending of email was successfull

In an API approach you would be able to call some url to check if your Accepted request was done processing or not, but this is another topic.
3
As I said before, this is basically an API, so all methods how to secure an API apply here. You can study those.
If you want to go simple and quick the easier ones are:

SSL + Http Basic Auth - simple basic auth when going over https is quite secure
SSL + ApiKey in header + Token Auth - basic thing for all API

I would not recommend going without SSL as you can always catch the request and read the keys.
Answer: Never call PHP mail() directly.
At least digest the sorry saga web2mail scripts first.
There are PHP Mail modules that escape line endings correctly.
Comment: "Never call PHP mail() directly" sounds like good advice, but please elaborate on the danger.
Comment: @200_success I updated the answer to tell why is that.

Minimal CORS mail PHP


Why did Chandler Bing get into the advertisement field?

Question: Chandler Bing was working with a firm and then he changes his job.
Why did Chandler Bing gets into advertisement field in Friends?
Comment: It's explicit in the episode: Chandler literally stops at the first idea offered by Monica, thinks it will be a fit, meets with Monica's friend, and gets an internship.
Answer: Because of monica, as explained here

On Christmas Day, Chandler quits his job so that he can fly home to
  New York to be with Monica. Monica helps Chandler secure a job in
  advertising through an old college friend of hers. Much to Chandler's
  dismay, the job is as an intern, which leaves him in the awkward
  position of working alongside people who are significantly younger
  than he. However, his more mature approach eventually pays off for him
  compared to the other interns, and he secures a full-time job in the
  business as a junior copywriter when he only expected to receive an
  assistant position. The company concluded that he would be better
  suited for a more senior role. (Source)
Comment: Advertisement was the first job alphabetically.
Comment: Why he chooses only advertisement and not other jobs? Was that a secure job?
Comment: @LoïcWolff: hehehehe. Chandler can do anything :P
Comment: and I think its because Chandler just hated his job. He always wanted to get out from it and do something else. So in that episode when he quits when it made him go away on x-mas eve, He decided to give his wishes a chance. He quits and found another field with help from Monica