How to parse an XML File
How does one parse XML files?
Prove that $\exp(x)>0$ using only formal definition of exp Can I disable full-disk encryption? I recently installed Ubuntu 12.10 and it requires a passphrase to boot up (I installed it with an encrypted file system).  Do I have to reinstall to change to a standard unencrypted file system? TV series from 70s or 80s - 1 female pilot was cloned from the other pilot's fingernail This was a tv show that aired in the US in the '70s or early '80s, possibly on Saturday mornings. Since I was a child, I'm assuming it was a kids program? It was comic science fiction and set on a spaceship. The only 3 specific details I remember are:   The crew traveled between ship levels by using open "jump tubes" that were similar to a giant vacuum tube message system, only without any "container" for the passenger. They just stepped into an alcove with a big hole in the floor and ceiling, then shot up or down. Frequently the show would use this as a source of slap-stick comedy.  The captain was male. The 2 pilots were female, and 1 had been cloned from the other's fingernail cell. They often disagreed about which one was the clone. What exactly is the cause of RAM incompatibility? I'm looking at rather short QVL lists from manufacturers, and I'm wondering what is the underlying cause of RAM incompatibility aside from the obvious: Obvious Reasons for Incompatibility  RAM Generation (DDR, DDR2, DDR3, DDR4) Form Factor / pin count RAM Type (ECC vs Non-ECC, Registered vs not, Buffered vs not) Minimum speeds on a board that cannot adjust the memory frequency Non-standard voltage range on a board that cannot adjust the memory voltage Channel count (single vs dual vs quad) Bad or inoperable module Mismatched set  Not Obvious Reasons  Brand SKU Max Capacity Speed too high  As in, why can't motherboard manufacturers just list the specifications of the RAM they will accommodate, and support every memory chip of that category instead of listing specific SKUs from specific brands? What happens electrically/physically that causes boards to fail to POST / operate with RAM that is otherwise 'compatible' with all of the specifications of RAM that is on the QVL? Interpretation of simple predictions to odds ratios in logistic regression I'm somewhat new to using logistic regression, and a bit confused by a discrepancy between  my interpretations of the following values which I thought would be the same:    exponentiated beta values  predicted probability of the outcome using beta values.    Here is a simplified version of the model I am using, where undernutrition and insurance are both binary, and wealth is continuous:  Under.Nutrition ~ insurance + wealth   My (actual) model returns an exponentiated beta value of .8 for insurance, which I would interpret as:     "The probability of being undernourished for an insured individual is .8 times the probability of being undernourished for an uninsured individual."   However, when I calculate the difference in probabilities for individuals by putting in values of 0 and 1 into the insurance variable and the mean value for wealth, the difference in undernutrition is only .04. That is calculated as follows:   Probability Undernourished = exp(β0 + β1*Insurance + β2*Wealth) /                              (1+exp(β0 + β1*Insurance + β2*wealth))   I would really appreciate it if someone could explain why these values are different, and what a better interpretation (particularly for the second value) might be.     Further Clarification Edits As I understand it, the probability of being under-nourished for an uninsured person (where B1 corresponds to insurance) is:  Prob(Unins) = exp(β0 + β1*0 + β2*Wealth) /               (1+exp(β0 + β1*0+ β2*wealth))   While the Probability of being under-nourished for an insured person is:  Prob(Ins)= exp(β0 + β1*1 + β2*Wealth) /            (1+exp(β0 + β1*1+ β2*wealth))   The odds of being undernourished for an uninsured person compared to an insured person is:  exp(B1)   Is there a way to translate between these values (mathematically)? I'm still a bit confused by this equation (where I should probably be a different value on the RHS):  Prob(Ins) - Prob(Unins) != exp(B)   In layman's terms, the question is why doesn't insuring an individual change their probability of being under-nourished as much as the odds ratio indicates it does?  In my data, Prob(Ins) - Prob(Unins) = .04, where the exponentiated beta value is .8 (so why is the difference not .2?) I've got a DVD that I've burnt from an MSDN ISO. I'm not entirely sure if its Windows 7 64bit or 32bit.   How can I be sure? set of almost complex structures on $\mathbb R^4$ as two disjoint spheres The set of almost complex structures on $\mathbb R^{2n}$ is given by $$ M_n = \frac{GL(2n,\mathbb R)}{GL(n,\mathbb C)} = \mathcal C_+ \sqcup \mathcal C_-,$$ taking into account that $\det = \pm 1$ gives two disjoint sets.  How do we show that $M_2=S^2 \sqcup S^2$? Moreover, I'm a bit confused by dimensions: how does $\dim_{\mathbb R}M_2=8$ relates with the latter decomposition?  This is exercise 1.2.1 from the book Complex geometry by Huybrechts. What does "more buyers than sellers" in technical analysis of stocks actually mean? I often hear/read technical analysts looking at volume and price action on a chart and claiming that there are "more buyers than sellers" or vice versa.  Since every trade requires a buyer and a seller, how can volume/price signify more of one than the other?  What does that actually mean?  When I hear that there are "more buyers," I get the impression they actually mean more "professional" or "institutional" buyers, but I could just be imagining that meaning.  But wouldn't this "more buyers" situation actually represent a smaller number of large buyers placing multiple orders? (and those orders would be matched by a larger number of smaller investors on the other side of the trade?)  Maybe I have my assumptions backwards and "more buyers" is what they say when they actually mean "more retail buyers and less institutional buyers"?  Or maybe the expression has nothing to do with number of buyers/sellers at all and is just some arbitrary technical analysis situation?  What situation is it that they're trying to describe?  If the "smart money" traders had placed larger orders, then there would have to be equally large sellers on the other side of that large trade, right?  I know trades often get broken up, but if the trades had been broken up it would be equivalent to "large traders placing multiple orders" scenario described above.  If the trades were not broken up, then there would not be an imbalance in the "number" of "smart" vs. retail buyers/sellers, right?  UPDATE/EDIT: I usually see this stated in reference to technical indicators such as RSI.  I don't typically hear people saying "there are more buyers than sellers" in the situations you guys are describing with more unfilled orders on one side of the (potential) trade (though that would make more sense if that was what they were talking about).  See for example: Applying MVT and IVT (?) to show something about f'''? (edit: actually, Taylor's Theorem using Lagrange remainder) Java: Date from unix timestamp The literature defines multinomial coefficients (or extended bnomial coefficients) as   $$ \binom{n}{r_1,r_2,\cdots,r_l} = \frac{n!}{r_1!r_2!\cdots r_l!}$$ where $$ r_1+r_2+\cdots+r_l = n$$  Which is the coefficient of $x_1^{r_1}x_2^{r_2}\cdots x_l^{r_l}$ in expansion of $(x_1+x_2+\cdots+x_l)^n$.  Question: How do we call the coefficients of $x^r$ in expansion of $(x+x^2+\cdots+x^l)^n$. Is it bad to name them multinomial coefficients?  In case of binomial coefficients the two are same in expansion of $(x_1+x_2)^n$ and the expansion of $(x+x^2)^n$. Obviously the two are different for multinomial expansion.   Example: As $(x_1+x_2+x_3)^2= x_1^2+2 x_2 x_1+2 x_3 x_1+x_2^2+x_3^2+2 x_2 x_3$. The coefficients are $\{ 1,2,2,1,1,2 \}$. Are these MULTI-NOMIAL?  $ As (x+x^2+x^3)^2=x^2 + 2 x^3 + 3 x^4 + 2 x^5 + x^6$. The coefficients are $\{1,2,3,2,1\}$. Are these too the MULTI-NOMIAL?  I prefer different terminologies to avoid confusion. Therefore want to know how these are distinguished in existing literature. What would be the sum of the following series?  $$\sum_{n=1}^{\infty} \frac{1}{n \cdot 2^n}$$  Thanks Should I really have been awarded mortarboard on a Per-site meta? How do users get started on new Stack Exchange sites? How do users on the new Stack Exchange sites get started? Each user starts with 1 rep, and can't upvote until they have 15 rep.  It struck me that this creates a bit of a deadlock. If a new user asks a question and a new user answers, neither can upvote the other.  Are we relying solely on existing SE users to join these exchange sites (with their bonus 100 rep) so that they can get started? Why does my procedure run slowly until I update statistics? I have a PCB with documentation. In the documentation, there is referred to specific pins of several jumpers and connectors. On the PCB however, there isn't a label or so for which pin has what number. I need to figure out which pin has which number, so that I know the function of each physical pin.  I noticed all connectors have all pins with a rounded tin pad, whilst one pin (either the first or the last when counting from right to left) has a square tin pad:     Is it some kind of convention which number this pin has? After that, how to count the other pins? Is there any way to tinker with the iPhone SDK on a Windows machine? Are there plans for an iPhone SDK version for Windows?  The only other way I can think of doing this is to run a Mac VM image on a VMWare server running on Windows, although I'm not too sure how legal this is. First post and late answer review queues always empty? Another point of view that $\mathbb{Z}/m\mathbb{Z} \times\mathbb{Z}/n\mathbb{Z}$ is cyclic. I was thinking that the product of groups $\mathbb{Z}/2\mathbb{Z} \times\mathbb{Z}/2\mathbb{Z}$ is not cyclic, but $\mathbb{Z}/2\mathbb{Z} \times\mathbb{Z}/p\mathbb{Z}$ is cyclic if p is an odd prime. Then I found logic that $\mathbb{Z}/m\mathbb{Z} \times\mathbb{Z}/n\mathbb{Z}$ is certainly cyclic if $m$ and $n$ are coprimes.  I searched on google a proof of that, to compare with mine and the answer is that $\mathbb{Z}/m\mathbb{Z} \times\mathbb{Z}/n\mathbb{Z}$ is isomorphic to $\mathbb{Z}/mn\mathbb{Z}$ (which is clearly cyclic) $\iff$ $m$ and $n$ are coprimes.  But I got another proof and I want to know what you think about it :     I claim that $([1]_m,[1]_n)$ generates $\mathbb{Z}/m\mathbb{Z}$   $\times\mathbb{Z}/n\mathbb{Z}$, where $[a]_d$ is the canonical   projection of $a\in \mathbb{Z}$ into $\mathbb{Z}/d\mathbb{Z}$.       Let's take multiples of $([1]_m,[1]_n)$ until we get $m \cdot$   $([1]_m,[1]_n) = ([0]_m,[m]_n)$ (where I suppose $m=\min(m,n)$...   otherwise, consider $\mathbb{Z}/n\mathbb{Z}$   $\times\mathbb{Z}/m\mathbb{Z}$ and $\min(m,n)=n$).       The next step is $([1]_m,[m+1]_n)$. This pair is not equal to   $([1]_m,[1]_n)$, since $m+1 \not\equiv1$ mod $n$ ($m$ and $n$ are   supposed to be coprimes). We can now continue adding $([1]_m,[1]_n)$   to the results.      The last step is precisely reached when you got   $([mn]_m,[mn]_n)=([0]_m,[0]_n)$. At this point, the fact that $m$ and $n$ are coprimes is absolutely necessary because if they are not coprimes, $lcm(m,n)\ne m\cdot n$ and   $([lcm(m,n)]_m,[lcm(m,n)]_n)=([0]_m,[0]_n)$ but all the $m \cdot n$ possible pairs are not reached, only the $lcm(m,n)$ are ! How can I delete my printer from Ubuntu? Using 12.04 my printer a canon ip2600 will not print.   SystemSettings/printers shows it as installed, connected to local host, enabled, accepting jobs, shared and allowing printing for everyone. Yet it does not print.   I have tried to remove it but get a request for user name and password which I enter (I only have one password) but the password is listed as incorrect.   I need a sudo command which I can use to delete the printer so I can attempt to re-install it. As it is the printer is useless and I can not even uninstall it.