We live in a world which is much larger than quantum world. The laws of quantum physics are not valid. While I am pressing the keys on my laptop, I have 100% certainty that I am writing what I really want.   Then  how is such microscopic world going to affect me?  The quantum world is entirely different, perhaps best suited for those Aliens.   Then why should I worry about uncertainty and other stuffs happening at infinitesimally  small scale?

The GPS is a very handy example in explaining to a broad audience why it is useful for humanity to know the laws of general relativity.  It nicely bridges the abstract theory with daily life technologies!  I'd like to know an analogous example of a technology which could not have been developed by engineers who didn't understand the rules of quantum mechanics.  (I guess that I should say quantum mechanics, because asking for a particle physics application could be too early.)  To bound the question:   No future applications (e.g. teleportation). No uncommon ones (for, who has a quantum computer at home?). A less frequently-cited example than the laser, please. If possible, for sake of simplicity, we'll allow that the quantum theory appears in form of a small correction to the classical one (just like one doesn't need the full apparatus of general relativity to deduce the gravitational red-shift).


Windows Spotlight showed me this picture. But no way to get the place it was shot.

Windows 10 has an extensive collection of lock screen photos, many of which have  here on Travel.SE.  Is there a website which lists the location of all of these photos? I imagine Microsoft has purchased an official license, so they should have a record about the photographer and the place where the photo was taken.


I'm trying to make the tab content take up 100% of the available space. but for some reason it is generating a vertical scroll because apparently it is adding the height of the tab. How can I make the content of the tab occupy the available space without generating the vertical scroll? I am using ng-bootstrap, if you are not familiar with angular don't worry, in this live code you should only see the styles.css file and /app/app.component.html:   Note: I can fix this with an overflow, but I want to know why I am getting this problem? Additional note: ngb-tabset adds 2 elements with class .tab-content and .tab-pane, I set them 100% height, otherwise the tab content would not grow. This is my code: <ngb-tabset [destroyOnHide]="false">   <ngb-tab id="nav-tabContent" class="h-100 border1" title="Relación causa con Emoción">     <ng-template ngbTabContent>
holi
     </ng-template>   </ngb-tab> </ngb-tabset>  body,html{   height:100%;   margin:0px;   padding:0px; }  .h-100{   height:100%; }  .tab-content {   height:100%; } .tab-pane {   height: 100%; }

I am working on a web application where I want the content to fill the height of the entire screen.  The page has a header, which contains a logo, and account information. This could be an arbitrary height. I want the content div to fill the rest of the page to the bottom.  I have a header div and a content div. At the moment I am using a table for the layout like so:  CSS and HTML    #page {     height: 100%; width: 100% }  #tdcontent {     height: 100%; }  #content {     overflow: auto; /* or overflow: hidden; */ }

...

...

     The entire height of the page is filled, and no scrolling is required.  For anything inside the content div, setting top: 0; will put it right underneath the header. Sometimes the content will be a real table, with its height set to 100%. Putting header inside content will not allow this to work.  Is there a way to achieve the same effect without using the table?  Update:  Elements inside the content div will have heights set to percentages as well. So something at 100% inside the div will fill it to the bottom. As will two elements at 50%.  Update 2:  For instance, if the header takes up 20% of the screen's height, a table specified at 50% inside #content would take up 40% of the screen space. So far, wrapping the entire thing in a table is the only thing that works.


I am using QGIS 3.12. Is there a way I can export my project to DXF including the information in the properties table, so I will be able to see the properties of the feature in AutoCAD?

Is it possible to export labels based on Shapefile attributes into a DXF file?  I use QGIS 1.7.4.  I've been reading a CSV file and view it as a Shape Layer. With the help of attributes from the File I will label the points. Now I want a DXF export with the labels. However, only the Points in the DXF file Export.  I do not have ArcGIS.  I am using AutoCAD LT 2011 for viewing DXF files. In AutoCAD I have to go through the "Insert / Link & extraction" under only the possibility to find data from Excel.


If $$ A =         \begin{bmatrix}         3 & 4 \\         4 & -3           \end{bmatrix}$$  Can someone find $\mathbf e^A$ ?  Edit 1:- I got this question in my fucntional analysis paper ! How is it even related to functional analysis ? Can somebody explain ?

For a 2x2 matrix A satisfying $A^k=I$, compute $e^A$  Oh, the exponential of a matrix is: $e^A=\sum_{i=0}^\infty\frac{1}{i!}A^i$    I thought I'd solved the $e^A$ form but I actually did something really silly, now I'm a little stuck.  If $A^k=I$ then $A^{k+1}=A$ and we have a cycle forming, so we will get:  $$\sum^{k-1}_{i=0}\sum^{\infty}_{j=1}\frac{1}{(kj+i)!}A^i$$  (Or something like this form, I don't have paper to hand and just spotted that now)  Is this what the question wants? It doesn't use the 2x2 property.  I believe the answer lies in finding an expression for the inner summation, I can do this for two terms (think of $e+e^{-1}$ all the odd power leave)


I would like to add on the x axis the value for each bar that are 400, 500, 600 and 700. I don't know why the only one that appears is 400.    The code I used is the following  \documentclass[a4paper,twoside,12pt]{article}  \usepackage[T1]{fontenc} \usepackage[utf8x]{inputenc} \usepackage[english]{babel} \usepackage{pgfplotstable}  \pgfplotsset{     discard if/.style 2 args={         x filter/.code={             \ifdim\thisrow{#1} pt=#2pt                 \def\pgfmathresult{inf}             \fi         }     },     discard if not/.style 2 args={         x filter/.code={             \ifdim\thisrow{#1} pt=#2pt             \else                 \def\pgfmathresult{inf}             \fi         }     } }  \begin{filecontents*}{ta.dat} T       K 400     1 500     1.4 600     0.5 700     1.6 \end{filecontents*}  \begin{document}  \begin{tikzpicture}     \begin{axis} [             ymin=0,             ybar, bar width=20, bar shift=0,             xtick=data,             ymajorgrids=true]             \pgfplotsinvokeforeach{400,500,600,700}{                 \addplot+[discard if not={T}{#1}] table [x=T,y=K] {ta.dat};             }     \end{axis} \end{tikzpicture}  \end{document}

I'm trying to draw the following plot:  \documentclass{standalone} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{pgfplots} \pgfplotsset{compat=1.9}  \begin{document}     \begin{tikzpicture}         \begin{axis}[             ybar,             ymin=0, ymax=90,             width=5.5cm,             height=6cm,             symbolic x coords={A,B},             xtick=data,             bar width=15pt,             axis lines*=left,             ytick={10,30,...,90},             nodes near coords,             xticklabel style={text height=1.5ex},             ymajorgrids,             enlarge x limits=.3,             ]             \addplot[fill=red] coordinates {                 (A,16.6)             };             \addplot[fill=green] coordinates {                 (B,23.9)                 };         \end{axis}     \end{tikzpicture} \end{document}   However it does not seem to work out: the second xtick coordinate (B) doesn't show up.  What I want is to have a simple plot with two or more bars each with a different color.  thanks for your help


I  can't do with anything unless I have her all to myself.   In this sentence, what does have mean? Does it mean control?

Annie wanted to have Helen all to herself so that she could do anything with her.   Note: In this context, Annie (full name, Annie Sullivan) is the teacher of Helen (full name, Helen Keller).  What is the meaning of "to have Helen all to herself", and is the clause "she could do anything with her" correctly used in the sentence? The sentence above is the answer to the question " Why did Annie want to have Helen all to herself?" The question was created from the passage " The next day, I told Helen's father, " I can't do anything with Helen unless I have her all to myself. I want her to depend on me for her food, her clothes,everything. ....."


I would like to know what is the best way to store fresh baked sourdough so that it maintains a nice crunchy crust and a nice soft, slightly moist, light texture?  I usually store it at room temperature in a large tupperware with a loose fitting lid or on the countertop. I have finally succeeded in baking the perfect sourdough; I am very happy:) I now just need to know what storage method I should use. I know it stores well in the freezer.

I'm currently baking a batch of sourdough bread. My last batch turned out perfectly with a hard crust and chewy inside. My problem is how to store the bread such that the crust stays hard. If I put it in a plastic bag the crust goes soft in a matter of hours and I'm afraid that the bread will turn dry if I leave it without some kind of protection. Note that I'm not looking for a long term storage solution.  What is the best way to store my bread, such that the crust stays hard and the inside stays chewy?


Consider the following exercise from the book Complex Analysis Stein and Shakarchi  I already proved that $\varphi(z)=z+a_nz^n+O(z^{n+1})$ and $\varphi_k(z)=z+ka_nz^n+O(z^{n+1})$, but I do not see how that with the Cauchy inequalities proves the linearity of $\varphi$. The Cauchy inequalities corollary states:

Let $G$ be an open and bounded region of $\mathbb{C}$, and let $f$ be analytic on $G$ so that $f(G) \subset G$ and, for some $a\in G$, $f(a) = a$ and $|f'(a)| = r$. (a) If $r < 1$, then $f^n \to a$, ($f^n$ converges to the constant function $a$ in the space of analytic functions) where $f^n := f\circ f\circ \cdots f$ ($n$-times) (b) If $f'(a) = 1$, then $f(z) = z$ for all $z \in G$.  For part (a), I have done the following: the family $\{f^n\}$ is normal by Montel's theorem, so for any subsequence $\{f^{n_k}\}$ there is a subsequence $\{f^{n_{k_s}}\}$ which converges to some analytic function $g$. Further, we know that $(f^n)'(a) = (f')^n(a) = r^n \to 0$ as $n \to \infty$.  Beyond that, I'm stuck. For part (b), I'm thinking that it is sufficient to prove the statement for when $a = 0 \in G$, and to show that the Taylor series for $f(z) - z$ must be identically 0.  But I'm also stuck here.


I was using a template for a book in overleaf:   Every time I try to use \[ \] the equation is not centered. It is added onto a new line, but not centered. In order to center it I have to use $$ $$, I would prefer not to as I have used the former for all my previous papers and I keep on having to rewrite it. I can't seem to find what part of the header edited the typical behavior of \[ \] or if it's something with regards to the documentclass (I have only used article up to now, it is my first time using the book class). Any help is greatly appreciated.

\documentclass[12pt, a4paper,fleqn]{report}  \doublespacing \usepackage[comma,super,sort&compress]{natbib} \bibliographystyle{rsc.bst}  \usepackage{comment} \setcounter{secnumdepth}{4} \usepackage{graphicx} \usepackage{amsmath} \graphicspath{ {images/} }   \begin{document} \section{Molecular dynamics simulations}   ....content....  \begin{equation} \centering m_\mathit{i} \frac{\delta^2\mathbf{r_\mathit{i}}}{\delta \mathit{t}^2}= \mathbf{F_\mathit{i}},\mathit{i} = 1....N. \end{equation}


Please answer the question in detail. I have tried other websites for answers but was not able to understand properly.

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


There's a site on Area 51 about Engineering, but I don't know if we have like a branch of that site talking about marine engineering. You know, like, the building of big ships, oil rigs, etc.

I have an idea or subject that should have a Q&A, and want to propose a new site. How can I do this?  Related:


I have been looking at the development of MMO games for a while and have got stuck up on one thing. Player Movement. If we have an area with 10 players, each player needs to be able to see the orientation and position of other players. But when players start moving I need to update the ten players locations simultaneously. If I were to use an MYSQL database it would be slow and laggy to send coordinates and get coordinates from the database everytime a player moved. What would be the professional and proper (more efficient) way of doing this?

How do you keep track of the positions of the players in a MMORPG? I read that you can use either a database or you can store the coordinates in files. I tried using a database but it was slow. How can files be used to keep track of players positions?


Let a=bq+r, then find a number u which divides both a and b (so that a=su and b=tu), then u also divides r since r=a-bq=su-qtu=(s-qt)u. (1) Similarly, find a number v which divides b and r (so that b=s^'v and r=t^'v), then v divides a since a=bq+r=s^'vq+t^'v=(s^'q+t^')v. (2) Therefore, every common divisor of a and b is a common divisor of b and r. I can't understand how is gcd(a,b)=gcd(b,r)?

Given: $a = qb + r$. Then it holds that $\gcd(a,b)=\gcd(b,r)$. That doesn't sound logical to me. Why is this so?    Addendum by LePressentiment on 11/29/2013: (in the interest of  and averting a duplicate)  What's the intuition behind this result? I only recognise the proof and examples solely due to algebraic properties and formal definitions; I'd like to apprehend the result naturally.


I am being tasked to remove ssh-keygen from Ubuntu servers and I don't want to break the computer. Can you please help, how to uninstall ssh-keygen utility safely? Thanks

I'm looking at removing password-based logins for SSH.  However, I don't want to allow passwordless ssh keys, as that would be even worse.  How can I make sure that only SSH keys which have passwords can connect?  If this can't be done, are there alternatives, like centrally managing SSH key generation, and preventing users from generating and/or using their own keys?  Something like PKI, I suppose.


I downloaded and installed the 3.0.0-21 update to the kernel. It caused several problems including:   Firefox not asking for a folder before placing a URL into bookmarks Ubuntu 11.10 not automatically opening to the desktop (I still haven't figuring out a viable work around).    This may be an inability to hibernate and reinstall, but I believe I also had problems after shutdown and booting.   I have tried to learn how to return to the former 3.0.0-19, but I can't find anything to teach me. I would like to know how to return to the -19 configuration or how to reinstall the -21 configuration.

The latest kernel is causing problems with my sound, which worked fine with an older version. As I have only Ubuntu installed, Grub is not getting displayed while booting. How can I manually choose my kernel version while booting?


I would like to convert   the hex value   a = 0x32    to a string d = 32  Bascially I have a  numpy array   msg = np.array[2, 50]   I need to convert both values to hex --- [0x02 , 0x32] then print the hex values as strings on GUI as 2, 32

How do I convert a hex string to an int in Python?   I may have it as "0xffff" or just "ffff".


Can someone help me out with this identity?  We are given two matrices $A$ and $B$. The matrix $A$ is $m\times n$ while $B$ is $n\times m$ matrix. We need to prove that     $\det(I+AB) = \det(I + BA)$ where $I$ is the corresponding identity matrix.   Please use elementary steps to solve as I don't have enough knowledge of matrices.  I checked out the Sylvester's determinant identity page in maths stack exchange. The proofs were out of my scope. Can it be done in an easier way?

Sylvester's determinant identity states that if $A$ and $B$ are matrices of sizes $m\times n$ and $n\times m$, then   $$ \det(I_m+AB) = \det(I_n+BA)$$   where $I_m$ and $I_n$ denote the $m \times m$ and $n \times n$ identity matrices, respectively.  Could you sketch a proof for me, or point to an accessible reference?


Let P be a prime ideal in a commutative ring R and let S = R\P, i.e. the complement of P in R. Pick out the true statements: (a) S is closed under addition. (b) S is closed under multiplication. (c) S is closed under addition and multiplication

Let $P$ be a prime ideal in a commutative ring $R$ and let $S=R-P$ ,i.e. $S$ is the complement of $P$ in $R$. Then, justify with reason which of the following(s) are correct:   $S$ is closed under addition. $S$ is closed under multiplication. $S$ is closed under both addition and multiplication.   The following argument provides a partial answer:  Let $P=3 \mathbb Z$ and $R= \mathbb Z$ the $2,4$ in $S$ but $2+4$ in $P$, so option 1. and 3. are incorrect.   But I don't know about 2.


I'm wondering about how to resize a text feild automatically in crm 2011. Is it possible there?  For example, I've got a simple text field that has 3 lines by default. And I'm looking for a method, which will resize a text field in order to show a data there without any scroll, if a wrote down 20 lines,.. whateever  Did anyone face that issue?

I deal with dynamics CRM 2011 online and I faced some troubles with printing documents there.   Could I resize/expand a text field in order to make a text visible for user without any scrolling?  Has anyone face this issue?


I need some help I cannot understand why my program doesn't record the right numbers. It will record parts of the number but skip the rest.  Example (How I want it):  Player Name: Lev Yashin Sign Up Time: 9 09 Sign In Time: 1 01 Player Name: Andrei Arshavin Sign Up Time: 6 09 Sign In Time: 12 15 Player Name: Igor Akinfeev Sign Up Time: 7 36 Sign In Time: 5 29 Player Name: Igor Netto Sign Up Time: 4 28 Sign In Time: 7 29   But when I run my code, I get:  Player Name: Lev Yashin Sign Up Time: 9 9 Sign In Time: 1 1   Its looking like it passes zeros, and I can't seem to understand why it does it. Once and awhile I will pass in some other data and it will produce all the numbers.  Anyone have any ideas on why it doesn't include some numbers?  int modifyStr(FILE *soccerWebsiteData, char firstAndLast[], char *pSignUpHours, char *pSignUpMinutes, char *pSignInHours, char *pSignInMinutes) { char *position = NULL; char oneLineOfFile[MAX_LENGTH]; char signUpHours = 0, signUpMinutes = 0, signInHours = 0, signInMinutes = 0;  while (!feof(soccerWebsiteData)) {     fgets(oneLineOfFile, MAX_LENGTH, soccerWebsiteData);     position = strchr(oneLineOfFile, ',');      strncpy(firstAndLast, oneLineOfFile, (position - oneLineOfFile));     firstAndLast[(position - oneLineOfFile)] = '\0';      signUpHours = atoi(position + 1);     *pSignUpHours = signUpHours;      position = strchr(position, ':');      signUpMinutes = atoi(position + 1);     *pSignUpMinutes = signUpMinutes;      position = strchr(position + 1, ',');      signInHours = atoi(position + 1);     *pSignInHours = signInHours;      position = strchr(position, ':');      signInMinutes = atoi(position + 1);     *pSignInMinutes = signInMinutes;      printf("Player Name: %s \n", firstAndLast);     printf("Sign Up Time: %d %d \n", signUpHours, signUpMinutes);     printf("Sign In Time: %d %d \n", signInHours, signInMinutes); } return 0;   }

I'm trying to find a good way to print leading 0, such as 01001 for a . While the number would be stored as 1001, what is a good way to do it? I thought of using either case statements or if to figure out how many digits the number is and then convert it to an char array with extra 0's for printing, but I can't help but think there may be a way to do this with the printf format syntax that is eluding me.


My background is in geometry, and I have a basic level of understanding of topological conjugacy: It defines an equivalence relation in the space of all continuous surjections of a topological space to itself, by declaring $f$ and $g$ to be equivalent if they are topologically conjugate ${\displaystyle g=h^{-1}\circ f\circ h}$ for some continous surjection $h$. So topological conjugation is like a "change of coordinates". (And I saw orbits of $g$ are mapped to homeomorphic orbits of $f$ through the conjugation, but I am not totally sure what orbit means here.)  Question: What does conjugacy mean in algebra? I learned conjugacy classes of a group measure, in some way, the degree of its commutativity (if the conjugacy classes are just singletons, the group is abelian).   My broader question, how are these concepts of conjugacy linked, i.e. which broader mathematical idea is captured through conjugacy?  EDIT: I would like to thank you for excellent comments. They are extremely helpful! I am very grateful and would like to give upvote credits to these comments. If you post them as an answer, so I can give credit, that would be greatly appreciated!

I'm studying cycle decomposition in group theory. The exercises on my book keep saying things like:   Find a permutation $\sigma$ such that $\sigma (123) \sigma^{-1} = (456)$ Prove that there is no permutation $\sigma$ such that $\sigma (1 2) \sigma^{-1} = (123)$ Show that $\pi(x_1 x_2 \cdots x_n)\pi^{-1} = (\pi(x_1)\cdots \pi(x_n))$   Why this  $\sigma \pi \sigma^{-1}$ appears every time in this book? Is this important for something? Could somebody give me a clear picture of how we arrive at this? Also, would be nice to know how to prove the third one, if somebody could help me.


We have an iMac in our office which we are going to put an SSD in (The iMac itself is past warranty and apart from the slow hard drive is functioning fine) however no-one of us in the IT Department are used to using Mac and we can't seem to work out how to re-install Mac OSX on a new hard drive as we can't seem to get a .iso file for MacOSX like you would with Windows  How would you re-install Mac OSX on a replacement Hard Drive

I want to install a new Solid State Drive (SSD) into the Mac. Can I just build in the SSD, start the MacBook in Recovery Mode and install OS X from there on?  After reading a lot on the internet I still have some doubts…  My HDD crashed, I can't repair it using disk utility or the fsck methods as mentioned on the internet.  According to  it should be possible.  I know how to replace the HDD with the SSD. I would go for the Samsung 850 EVO SSD - 500GB. My Mac is a MacBook Pro Mid 2012, model A1278.


For an ARIMA (0,0,1) model, I understand that R follows the equation: xt = mu + e(t) + theta*e(t-1) (Please correct me if I am wrong)  I assume e(t-1) is same as the residual of the last observation. But how is e(t)  calculated?  For example, here are the first four observations in a sample data: 526 658 624 611  These are the parameters Arima(0,0,1) model gave: intercept = 246.1848 ma1 = 0.9893  And the first value that R fit using the model is: 327.0773   How do I get the second value? I used: 246.1848 + (0.9893*(526-327.0773)) = 442.979  But the 2nd fitted value given by R is : 434.7928  I assume the difference is because of the e(t) term. But I do not know how to calculate the e(t) term.

This is a basic question on Box-Jenkins MA models. As I understand, an MA model is basically a linear regression of time-series values $Y$ against previous error terms $e_t,..., e_{t-n}$. That is, the observation $Y$ is first regressed against its previous values $Y_{t-1}, ..., Y_{t-n}$ and then one or more $Y - \hat{Y}$ values are used as the error terms for the MA model.  But how are the error terms calculated in an ARIMA(0, 0, 2) model? If the MA model is used without an autoregressive part and thus no estimated value, how can I possibly have an error term?


I'm inclined to use parvenu but most meaning suggest about lacking refinement. I'm looking for someone who looks down on the poor. Maybe abusive to the poor.

What is a single word in English which means to look down on others (due to their younger age, lower socio-economic position, lesser experience, etc)    Not look down upon everyone else in general, but look down upon some particular person due to a feeling of superiority of oneself over them ( this superiority may come from the fact that one feels has more money, talent, etc)?    By "look down upon" I don't mean just the feeling of having superiority over another, but acting to them in a manner that reflects this pride as well (for example, perhaps he acts very rudely to them, since he feels superior to them and feels he can get away with it, or he feels it doesn't matter at all due to his superiority)


All the ads for my website have been disapproved last week due to malicious (third party) software. I checked the whole website and noticed the third party script on the header section related to Localmed. But I have removed all scripts and scanned the whole site again and found no malware now. But my ads are still being disapproved again and again. Can you please help me as I am losing my business due to this reason. I have also attached the screenshot for your reference.

Had my website hacked through a plugin 3 weeks ago.  rebuilt the site with a new wordpress site (hosted on Godaddy wordpress pro).  this was a fresh build.  All the built in malware checks in wordpress plugins and also google's console checks are good and clean.  Google ads wont run as it reports I have three malicious links in my website.  They gave me the link addresses but they are nothing I can locate.  Anyone have ideas on how to find what google found?


I want to know how to create a Ubuntu based Install Media that has an customized Ubiquity installer that has custom branding and custom packages. I don't just want to create a ISO file of a system, I want an installer.   I also don't want to create my own mirror, just want to use the default Ubuntu mirrors.   (Pretty much I want to create a custom Ubuntu flavor for myself)  I can't find how to do this in a simple way anywhere. I AM READING the DebianCustomCD page on the Debian Wiki but it doesn't go over editing the Ubiquity Installer which is one of the main things I am trying to do.

I'd like to create a customized Ubuntu Server 12.04 ISO but couldn't find a clear approach on how to do it. I see that Ubuntu-builder is a very good app to create a customized Ubuntu Desktop, but what about Ubuntu Server?


I understand how photons can change wavelength via gravitational redshifting, but that doesn't  seem to be what's going on with the CMB radiation. I've heard it explained as happening because of the expanding universe, but I'm thinking that would have to imply that as the universe expands, lower wavelengths have higher energy, so to conserve energy, the CMB would have to redshift. Is that the case, or is something else going on?

So I have learned in class that light can get red-shifted as it travels through space. As I understand it, space itself expands and stretches out the wavelength of the light. This results in the light having a lower frequency which equates to lowering its energy.  My question is, where does the energy of the light go? Energy must go somewhere!   Does the energy the light had before go into the mechanism that's expanding the space? I'm imagining that light is being stretched out when its being red-shifted. So would this mean that the energy is still there and that it is just spread out over more space?


Function prototypes:  1. int test (int & i); 2. int test (int * i);   Function calls:  1. test(n); 2. test(&n);   Can anyone explain the difference in as many aspects as possible? Thank you so much!

I know references are syntactic sugar, so code is easier to read and write. But what is the difference between a pointer variable and a reference variable?


There are 2 complexes computing Cech cohomology. The difference between them is that in the second one we require skew symmetry when you change the order of indices. How to show that they are quasi-isomorphic? Let $C(U,F)$ be the first and $C'(U,F)$ the second. Open sets are indexed by the set $I$ with some perfect order. There is inclusion $i: C'(U,F) \to C(U,F)$. There is projection $h: C(U,F) \to C'(U,F)$, defined by $$ (hc)_{i_0...i_n}=sgn(\varepsilon) c_{i_{\varepsilon_0}i_{\varepsilon_1}...} $$ I failed to construct a homotopy $k:C(U,F) \to C(U,F)[1]$ such that  $$ 1-ih=dk+kd. $$ Could you help me?

Let $X$ be a topological space with and open cover $\{U_i\}$ and let $\mathcal F$ be a sheaf of abelian groups on $X$. A $n$-cochain is a section $f_{i_0,\ldots,i_n}\in U_{i_0,\ldots,i_n}:= U_{i_0}\cap\ldots\cap U_{i_n}$; we can costruct the following abelian group (written in additive form):  $$ \check C^n(\mathcal U,\mathcal F):=\!\!\prod_{(i_o,\ldots,i_n)}\!\!\mathcal F(U_{i_0,\ldots,i_n}) $$  Now my question is the following:  we consider  oredered sequences $(i_o,\ldots,i_n)$ ? Because in this case in the direct product we have each group repetead $(n+1)!$ times, that is the number of permutations of the set $\{i_o,\ldots,i_n\}$.


If I have a dependent variable Y and two independent variables X1 and X2 , that are highly correlated.   Y ~ beta1*X1 + beta2*X2    What issues can multicollinearity cause in an OLS regression, apart from unstable beta1 and beta2 estimates ?

The wiki discusses the problems that arise when  is an issue in linear regression. The basic problem is multicollinearity results in unstable parameter estimates which makes it very difficult to assess the effect of independent variables on dependent variables.  I understand the technical reasons behind the problems (may not be able to invert $X' X$, ill-conditioned $X' X$ etc) but I am searching for a more intuitive (perhaps geometric?) explanation for this issue.  Is there a geometric or perhaps some other form of easily understandable explanation as to why multicollinearity is problematic in the context of linear regression?


Why does it skip through the defined function without running it?  The goal is to call the last if and else conditionals only after everything_but_the_end() has run, however the program just skips them. My code was running fine before I made the function (so that I could call it back to replay), but now it is not running as intended.   import random  rand_num = random.randint(1, 10)  guesses_total = 5  guesses_so_far = 0   def everything_but_the_end():     while guesses_so_far < 5:         print("Hi, I'm thinking of a number, 1 - 10.")         guess = int(input("Guess what number I am thinking of: "))         if guess == rand_num:             guesses_so_far = guesses_so_far + 1             break         elif guess < rand_num:             guesses_so_far = guesses_so_far + 1             print("Too Low \n--- Attempt {}".format(guesses_so_far))         elif guess > rand_num:             guesses_so_far = guesses_so_far + 1             print("Too High \n--- Attempt {}".format(guesses_so_far))   if guesses_so_far > 4:     play_again_lost = input("Sorry, you lost. Play again? Y or N: ")     if play_again .upper() == "Y":         everything_but_the_end()     else:         print("Okay, goodbye!")         quit() else:     play_again = input("Congrats! You won! Want to play again? Y or N: ")     if play_again .upper() == "Y":         everything_but_the_end()     else:         print("Okay, goodbye!")         quit()   I thought to solve it by just putting everything_but_the_end() after I defined it, but it gives me two errors, that   Traceback (most recent call last):   File "/Users/danielternyak/Google Drive/PythonPrograms3.4/randnum.py", line 24, in <module>     everything_but_the_end()   File "/Users/danielternyak/Google Drive/PythonPrograms3.4/randnum.py", line 11, in everything_but_the_end     while guesses_so_far < 5: UnboundLocalError: local variable 'guesses_so_far' referenced before assignment   I am unsure why I am receiving this error, as I have already defined guesses_so_far at the very top of the page.

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I am looking at purchasing a used Surly Pacer. However, the owner is unsure of the year (he also bought it used). Are there any visual cues that I can use to identify the year of the frame?

This is a canonical question that will hopefully encompass all of the questions we get asking us to determine what year a bicycle was manufactured (how old is my bike, how old is my frame, etc.). Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at.  The span of answers would include things such as:      Skiptooth cranks Cartridge bottom brackets (BB30/90 etc) Elliptical chainring Quick releases versus contemporary through-axles How the steerer attaches to the fork (quill vs. threadless)  Braking system (especially with mountain bikes: v-brake, direct pull, etc.)   Shifting ramps and pins on cassettes/sprockets and chainrings (versus flat sprockets) Frame material (e.g., shift from tubular steel to use of CF and hydroformed aluminium)  Frame tubing type (e.g. Reynolds 531 tubing introduced around 1934, still used today; Reynolds 501 tubing introduced around 1983). So a frame with an original 501 decal can't be from the 70', 531 decal doesn't help as much because of the range of years produced. Also, see Decals.   *Decals: style/design, amount, placement, color, etc. can help not only determine models, but also year of manufacture. Many changed decal design for the same model bike often yearly, with special/limited editions even more specific. This applies only if decals are original or have been replaced with the identical design. Tubing decals (Reynolds, Columbus, etc.) also changed designs for same tubing made in different years, although the changes aren't made as often, and manufacturers didn't always put tubing Brand decals on every model. Earlier bikes tended to have less fancy, less colorful, less quantity of decals.   Headbadges: most early bikes had actual "badges", often quite detailed and fancy, made of metal, then plastic, and finally just using decals on the headtube. Most bikes lost their metal badges in the 60's and early 70's, although some brands still have actual badges to this day, but in general a real badge indicates an earlier model bike. Dropout style (including the later inclusion of lawyers lips) Presence or absence of CPSC reflectors (USA only) Manufacturing method (shift from lugs to TIG welding, for example)  Number of gears (shift from 2x5 ten-speed to 3x8, 2x9, 1x11, etc.)  Inspection of lug design: pantographs, cut-out, stampings, custom brazing/filing, chrome, fork crow n sweep, etc. Frame/Fork Braze-ons. Race bikes tended have less braze-ons the earlier the year of manufacture. Most 60's racers and earlier had few or none with cable guides/stops, shifters, bidons, etc. being clamp-on. By the 80's if it was clamp-on, it was a sign of very cheap models and most frames had braze-ons for all cables, with multiple bottle and accessory bosses depending on style and use.   and so forth. Please edit this question if you have an answer that isn't in the index above.   A couple of caveats:   A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment There is a delay between the introduction of a technology (such as indexed shifting) and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology that is severely outdated (such as one-piece cranks, freewheels, or quill stems) because it is cheaper to do so. A number of bikes are built in a Retro style, but with modern components.  Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be 1950s styling.  These tend to have modern rims and brakes as a giveaway.     Note that bicycles.stackexchange does not do valuations of bicycles. How much your bicycle is worth depends on the location of the buyer and seller, how much the buyer wants the bike, etc. etc. etc.


Let M be a compact Metric space. Consider the function $f: M \to M$ where $d(x,y) \leq d(f(x),f(y))$ (this is called an expansion map). Show that f is an isometry, that is $d(x,y) = d(f(x),f(y)), \forall x,y \in M$ Hint: Show that $\{f^n(x)\}$ has a subsequence that converges to x. Once this is shown, show that the sequence $\{(f^n(x),f^n(y))\}$ has a convergent subsequence in the product metric. I've tried to work with the hint, but I'm having a hard time here. Isometry is a fairly new term for me, so I could use some help getting started. Thank you, everyone!

I got inspired by this question  to think about the following problem: Suppose you have a compact metric space $(X,d)$ and an expanding map $T:X\rightarrow X$, i.e. $d(Tx,Ty)\geq d(x,y)$ for every $x,y\in X$. Is the map $T$ then continuous? Without assuming continuity we already know that $T^n(X)$ must be dense in $X$ for any $n\geq 1$, since given $z\in X$ the orbit of $z$ must accumulate upon $z$. But showing continuity has escaped me so far. If there are counter-examples using the Axiom of Choice that also interests me.


Where $\sigma_0(n)$ is the divisor function, are there any integers $n$ such that $\sigma_0(n) = n$? I already know that $n=1, 2$ work, but are there any others?

For a a positive integer $n$, let $d(n)$ denote the number of divisors of $n$. I'm trying to prove that:   1) For $n>6$ we have $d(n)\leq\frac{n}{2}$;  2) For $n>12$ we have $d(n)<\frac{n}{2}.$  Can someone help me?


this code worked fine in the Oracle live sql but when i put it on the server im getting a SQL command not properly ended was wondering if its because its different oracle versions, the server is in oracle11g SELECT g.GID, g.Name, COUNT(*) as cnt FROM VisitN v JOIN      GuestN g      ON v.GID = g.GID GROUP BY g.GID, g.Name ORDER BY cnt DESC FETCH FIRST 1 ROWS ONLY;   thank you

Is there a way to make an Oracle query behave like it contains a MySQL limit clause? In MySQL, I can do this: select *  from sometable order by name limit 20,10  to get the 21st to the 30th rows (skip the first 20, give the next 10). The rows are selected after the order by, so it really starts on the 20th name alphabetically. In Oracle, the only thing people mention is the rownum pseudo-column, but it is evaluated before order by, which means this: select *  from sometable where rownum <= 10 order by name  will return a random set of ten rows ordered by name, which is not usually what I want. It also doesn't allow for specifying an offset.


I watched a few episodes of this cartoon a few years ago. All I can remember about it are as follows:   there are these bad robots that are part metal, part plant the good guys travel to several planets in a sailing ship-like spaceship the main character (male) is looking for his father   Does anyone know what the name of this series is?

Been trying to track down some of my old favorites from the 80s era of anime, one that has refused to show up in search after search has brought me here with the hope that someone might know of it.  Details: Sci-fi anime series (viewed on American TV early weekday mornings) during the 80s. Heroes drove cars and enemies were cars, with the heroic cars being high-tech and each unique, and enemies being some organic spore-based grow-on-demand instant cars. One of the latter had a bola style weapon, forget the others.  Characters were quite obviously modelled after Star Wars 4, I forget what their cars were capable of except in one case:  -"Han" owned the starship they traveled on, "Luke" was main character (?), "Ben" and "Leia" rode in the same car, which had a drill for going underground.  As far as what year the title was aired, I can't say for certain, around the mid 80s I can say confidently.


The inequalities are:  $$\liminf(a_n + b_n) \leq \liminf(a_n) + \limsup(b_n) \leq \limsup(a_n + b_n)$$

I am stuck with the following problem.     Prove that $$\limsup_{n \to \infty} (a_n+b_n) \le \limsup_{n \to \infty} a_n + \limsup_{n \to \infty} b_n$$   I was thinking of using the triangle inequality saying $$|a_n + b_n| \le |a_n| + |b_n|$$ but the problem is not about absolute values of the sequence.  Intuitively it's clear that this is true because $a_n$ and $b_n$ can "reduce each others magnitude" if they have opposite signs, but I cannot express that algebraically...  Can someone help me out ?


I am using Ubuntu on Windows 10. I've created a user id and there I created some folders. Now I want to copy those folders to my Windows folder in, say, E: drive. How can I get access to the folder that I created in Ubuntu in the Windows interface? I made that folder in /home/user/directory.

I am a super newbie for Ubuntu and basically need Ubuntu for a Python package.  I would like to run a Python file in say e:/username/folder1/folder2/python.py. I tried every method online and the only reply is bash: cd./e: No such file or directory. I am not sure whether it is because of the bash windows or virtualenv.  When I use bash on Ubuntu on Windows, ls, it says VIRTUALENV_DIR. cd, it says /home/username. The cd .. etc changes the directory a little, but not another drive, nor the folder I would like it to find.


I have an old Pentium 4 machine which has Windows XP installed in it. The installation of XP is unstable and crashes frequently. So, I decided to install Kali on it which failed due to hardware kernel panic. Tried 32bit version and fail due to the same reason. Tried ubuntu(16) 32bit and 64bit. And it failed again. Tried bios update. Success but when I tried to install it failed again. The specs are as follows:  Intel Pentium 4  Intel 865GSA Desktop board  2gigs of DDR memory  edit:  checked

I'm thinking about installing Ubuntu Desktop, but I don't know what flavor is the best for my system. What are the minimum and recommended hardware requirements? What kind of CPU? How much memory? Should I have Hardware Acceleration? What flavor should I use?  This is an attempt of a canonical answer. My answers have the "official  requirements", the recommended are a mix of official sources and opinion based (along with the answer it's told the source). You can comment or edit if you feel that the information is obsolete or incomplete. It is a good rule of thumb that any system capable of running Windows Vista, 7, 8, x86 (Intel) OS X will almost always be a lot faster with any Ubuntu flavor even if they are lower-spec than described below.


If an elevator with one man in it, is accelerating as it moves upwards, the reaction force the floor exerts on the man will be more than the weight of the man. Why is that though? Shouldn't the weight and the reaction force be the same, as action reaction forces are always equal?

This is a question on a worksheet that I'm giving to a student:  A man of weight $W$ steps into the lift. The lift then moves downwards with a constant speed. If $R$ represents the force acting on the man by the lift floor, which of the following statements is/are correct? (3) $R$ and $W$ are an action-reaction pair according to Newton's third law  Why isn't this statement (3) correct?


I am using data table in lightning component.I am referring one column in data table as formula field.That formula field returns image of text type.When i display that field in Lightning component, the image is not displaying.Instead it is displaying the URL. Can anyone help on this issue. can we display images on the datatable?  Following code i am using to display the columns in data table.  Component:  <lightning:datatable columns="{!v.columns}"                      data="{!v.data}"                      keyField="Id"                                                                              hideCheckboxColumn="true"/>   Controller code:  component.set('v.columns', [             { label: 'formulafield', fieldName: 'formulafield__c', type: 'text', initialWidth: 350, editable: false, sortable :true },          ]);   Formula field:  IF(NOT(ISBLANK(field1)), IF(field2 >= TODAY(),  IMAGE("/resource/name","some text",10,10),  IMAGE("/resource/name1","some text",10,10)),IMAGE("/resource/name2","some text",10,10))   out put in the lightning component:  <img src="/resource/name" alt="some text" style="height:10px; width:10px;" border="0"/>

Canonical Question  I want to do <some really cool thing> with a lightning:datatable, but I can't seem to figure out how to do it. I checked the , but I did not see a way to implement <this really cool feature I need>.  Perhaps I want to provide tooltips, or a pick list, or alter the behavior of the menus, or display images, or show a custom component I created, or define a new row-level click behavior, or alter the keyboard event handlers, etc.  Can I somehow do this?


What I did:   Change render engine to Cycles Add Suzanne Add plane Scale plane by 5 Change environment texture to HDRI from  Change Suzanna node setup Change plane node setup (use default principled BSDF, add image textures for diff (diffuse), spec (specular), rough (roughness), normal, disp (displacement)) Change all image textures to non-color data except for diff (diffuse) and normal   The specific texture for the plane is . I am given the option to download:   Diffuse AO (unused) Bump (unused) Displacement Normal Roughness Specular   Is this the correct node setup to use the texture and how do I connect the unused textures?  I am using Blender 2.82a. The wood plane looks flat to me even though I added the normal and displacement nodes.  Nodes:    Render:

I created some texture maps in MindTex to use in Blender, but I can't figure out how to properly hook them up. The maps I have:  - Diffuse  - Normal  - Height   - Specular   - Gloss   - Self Illumination  - Reflection  - Ambient Occlusion   MindTex (left) vs. Blender (right)  As you can clearly see it's a pretty big difference.  is my material node setup in Blender. In the examples I don't actually use self illumination or reflection images, but including this in the answer would be helpful.


I installed software using the sudo apt-get install [program name] command in the Terminal.  How should I go about uninstalling said program via. Terminal?  What should I specifically type in the Terminal?   The program does not appear in the Installed tab of Software Center It exists in the Software Center, but according to Center it hasn't been installed The program operates fine though when installed using above command

Seeing there are various ways to install on Ubuntu. What are the various ways to uninstall items?  Which ways always work? How can I be sure something was uninstalled?


A good example would be a giant screen in a football stadium. The last rendered frame would be used as texture on the screen for the current frame.  This texture would be emitting light (as it is a screen), so I really need it as a texture input for an emission shader in cycles.  It differs a bit from that question:  as the given solution gives me a pink screen on the ~20 first frames.  Is it possible in Blender and if yes, how?

Is it possible to use the rendered output of one renderlayer in the materials on another render layer?  How can I achieve this?


May I know how == works here?  public class App {     public static void main(String[] args) {         String s1 = new String("str");         String s2 = new String("str");         System.err.println("why it,s "+String.valueOf(s1==s2));         int i1 = new Integer(10);         int i2 = new Integer(10);         System.err.println("why it,s "+String.valueOf(i1==i2));     }      }  When I am comparing references of two different String with the same values, then == says that they are not equal, but when I am comparing references of two integers with the same values, then == says that they are equal. Why is it so?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Is crafting magical items official in D&D 5e? I googled it, but 90% of everything I found is homebrew. If crafting is official, how do you do it, and what can you make? Is there some sort of list or something?

Are there any class, proficiency, or skill requirements to craft a magic item in D&D 5th edition other than to possess the minimum character levels?   I.e. 3rd level for Common and Uncommon Magic Items, 17th level for Legendary Items.


I have a big sql dump with long lines and I would like to use grep to find a certain text string.  grep text_string filename.sql   returns the result lines which are huge and difficult to see where my text_string appears. What I want to achieve is to get a result that contains lets say 50 characters to the left and 50 to the right of the search term (text_string). Is this possible?

I have to grep through some JSON files in which the line lengths exceed a few thousand characters. How can I limit grep to display context up to N characters to the left and right of the match? Any tool other than grep would be fine as well, so long as it available in common Linux packages.  This would be example output, for the imaginary grep switch Ф:  $ grep -r foo * hello.txt: Once upon a time a big foo came out of the woods.  $ grep -Ф 10 -r foo * hello.txt: ime a big foo came of t


I noticed that when I post a question, there's always at least one view  Asked today   Viewed 1 times   Is the 1st view always the OP?

Are the questions submitted on SO and other SE sites initialized with 1 view, or does the first view belong to the user who posted it?  Why is a question given a free first view? It just appears, as soon as the question is published.


I'm trying to code a simple program for my friend who is obsessed with Sonic and the phrase "GOTTA GO FAST". The problem is, whenever I try to use scan.nextLine() as part of an if statement, it never works.     import java.util.Scanner;  public class meaningOfLife {     static Scanner scan = new Scanner(System.in);     private static String guessah = "Going fast";     private static boolean areTheySmart = false;      public static void howDoesOneGoFast(){         while(!areTheySmart){             System.out.println("What is the meaning of life? ");             if(scan.nextLine() == guessah){                 System.out.println("YES");                 for(int i = 0; i >= 0; i++){                     if(i < 10){                         System.out.println("STARTING TO GO FAST");                     } else if(i < 30){                         System.out.println("GOING FAST");                     } else if(i < 60){                         System.out.println("GOING FASTER");                     } else if(i < 100){                         System.out.println("GOTTA GO FAST");                     } else if(i < 150){                         System.out.println("GOTTA GO FASTER");                     } else{                         System.out.println("FASTER FASTER FASTER FASTER FASTER");                     }                 }             } else{                 System.out.println("WRONG");             }         }     }     public static void main(String[] args){         howDoesOneGoFast();     } }   At if(scan.nextLine() == guessah), the Scanner takes a String as input, and even if I copy-paste "Going fast" into the Scanner-field it doesn't properly copy it. I entered 'Going fast' into the scanner field at least 20 times, each with small variations but it still doesn't see it as an equal to "Going fast" (guessah's value).


I have video with multiple audio streams. eg: isolatedApp, combinedAppAndVoice I want to remove the voice component, and retain the application audio only, in a specific time segment. Assume I need to use ffmpeg. ie: combinedAppAndVoice -ss 00:00:00 -to 00:00:10  isolatedApp         -ss 00:00:10 -to 00:00:20 combinedAppAndVoice -ss 00:00:20 -to 00:00:30   Do I need to chop the media up with specific streams and concatenate the relevant parts? Or can I use a filter/other magic to do it in a single operation? [edit] llogan's reference is correct, I also figured it out last night, so this edit is to add an answer/clarification for this particular case. -filter_complex \ "[0:a:1]atrim=start=0.000:end=10.000,asetpts=PTS-STARTPTS[a0]\ ;[0:a:0]atrim=start=10.000:end=20.000,asetpts=PTS-STARTPTS[a1]\ ;[0:a:1]atrim=start=20.000:end=30.000,asetpts=PTS-STARTPTS[a2]\ ;[a0][a1][a2]concat=n=3:v=0:a=1[switchedAudio]" \ -map 0:v:0 \ -map [switchedAudio] \ etc

I figured out how I can concatenate multiple audio files with complex filter, but struggling with offsetting audio in result file. Say, I want to add a gap of 1 seconds silence between each concatenate file. Is it possible to do with FFmpeg?


If they already have the documentation, visa, passport and air tickets, can they be stopped at the Moscow airport by their own Customs agents and be made to show proof of funds before being allowed to board?

On Travel.SE we often see questions about a person (usually a love interest) asking for money to pay for airfare, visas, permits and other expenses. For example        What general advice can be given in such situations to the person asking the question? Is it all a scam or can there be legitimate situations in which an online friend could be asking for money?


I installed Ubuntu 12.04 LTS in Windows 8.1 using vmware workstation. When I open a file in the terminal using vi filename.c, the arrow buttons will not work properly, pressing up arrow prints A, down arrow B, right arrow C,left arrow D. How can I overcome this problem?

I am open a file in vi:  vi index.php   Here the problem is: when I press the down arrow and it prints 'B'. Why it prints 'B'?


I recently installed Ubuntu 20.04.  I am unable to find the alias command.  When I enter which alias I get nothing back.  Same with whereis alias.

I used which to tell the location of a runnable file. For example, which pwd returns /bin/pwd. However, I found which alias or which compgen etc returns nothing.   What are commands like alias? Aren't they executable files on my Linux? I am using bash 4.3 on Ubuntu.


The 180th day is September 25 in US after staying 90 days in the Schengen Zone. Could I leave US by plane on 25th (180th day) to arrive Schengen next day, 26th, without any trouble?  (Just need to know if it is okay to get on the plane on 25th (180th day) leaving U.S. for Schengen Area next day, 26th that becomes new 90 days. OK TO LEAVE U.S. on 180th day?)

I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation?


Whats the difference between isAccessible() vs isQueryable() methods in DescribeSObjectResult Class and which method should one use for CRUD checks in SOQL query ?   ()  From documentation they look synonymous .

What does is actually mean when a user  can 'query' an Object?  In other words: what rights does a user have when the Object.isQueryable() returns True?  Pages like  only say that isQueryable returns whether the user can 'query' the object. But what does that mean?


I am trying to segment an image by first dividing it into superpixel, and than classifying those superpixel to merge them together. If I am doing it for example with a SVM or a Decision Tree, it works fairly well, but is still doing some mistakes.  Now I wanted to use an Neural Network, to do the task, but after a few iterations it almost always gets stuck in the local minima and "maps every input to the same class".   It behaves in general really weird, because sometimes the accuracy first increases, but than steadily decreases again, till it reaches one of the minima from above (I am talking about the train accuracy, not the test accuracy, so overfitting is not an explanation, I also don't use Stochastic gradient descent but use all train data for an weight update, so fluctuations cant really explain the decreasing accuracy)  That looks like this:  617/617 [==============================] - 1s - loss: 1.1174 - acc: 0.2690       Epoch 2/1000 617/617 [==============================] - 0s - loss: 0.8662 - acc: 0.8169      Epoch 3/1000 617/617 [==============================] - 0s - loss: 0.5829 - acc: 0.8136      Epoch 4/1000 617/617 [==============================] - 0s - loss: 6.3685 - acc: 0.9060      Epoch 5/1000 617/617 [==============================] - 0s - loss: 9.0494 - acc: 0.4036       Epoch 6/1000 617/617 [==============================] - 0s - loss: 4.4840 - acc: 0.1297      Epoch 7/1000 617/617 [==============================] - 0s - loss: 1.9398 - acc: 0.1167      Epoch 8/1000 617/617 [==============================] - 0s - loss: 1.8809 - acc: 0.1167    (It stays at the same loss and acc from there)  The NN I am using looks like this (even though I also tried many others):  from keras.models import Sequential from keras.layers import Dense, Dropout from keras.optimizers import SGD enc = OneHotEncoder() labelOH = enc.fit_transform(label.reshape(-1,1)).A  clfN = Sequential() clfN.add(Dense(32, input_dim=feature_array.shape[1])) clfN.add(Dense(64, activation="relu")) clfN.add(Dense(64, activation="relu")) clfN.add(Dense(32, activation="relu")) clfN.add(Dense(labelOH.shape[1]))  sgd = SGD(lr=0.0001, decay=1e-10, momentum=0.9, nesterov=True) clfN.compile(loss='categorical_crossentropy',               optimizer=sgd,               metrics=['accuracy']) clfN.summary() clfN.fit(feature_array, labelOH,  epochs=1000, batch_size=617)   What could be the cause for this behaviour, and what could I do about it?

I'm training a neural network but the training loss doesn't decrease. How can I fix this?  I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set.    This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion:   If your neural network does not generalize well, see:


I've noticed that kernel.shmmax value is set to oddly huge number on my RHEL 7 system.   # sysctl kernel.shmmax kernel.shmmax = 18446744073692774399    Is it OK to have such a huge number set? How can it affect the system? What exactly that parameter means?   Some info about the system:   # cat /etc/redhat-release Red Hat Enterprise Linux Server release 7.2 (Maipo)  # cat /proc/meminfo MemTotal:        9037028 kB MemFree:          175220 kB MemAvailable:    2544492 kB Buffers:               0 kB Cached:          2716836 kB SwapCached:        14908 kB Active:          5749708 kB Inactive:        2371364 kB Active(anon):    4490064 kB Inactive(anon):  1120848 kB Active(file):    1259644 kB Inactive(file):  1250516 kB Unevictable:       10800 kB Mlocked:           10796 kB SwapTotal:       5242876 kB SwapFree:        5143688 kB Dirty:              9704 kB Writeback:             0 kB AnonPages:       5400268 kB Mapped:           318000 kB Shmem:            202700 kB Slab:             379036 kB SReclaimable:     169128 kB SUnreclaim:       209908 kB KernelStack:       34080 kB PageTables:        46252 kB NFS_Unstable:          0 kB Bounce:                0 kB WritebackTmp:          0 kB CommitLimit:     9761388 kB Committed_AS:    7599336 kB VmallocTotal:   34359738367 kB VmallocUsed:      181868 kB VmallocChunk:   34359341052 kB HardwareCorrupted:     0 kB AnonHugePages:   1861632 kB HugePages_Total:       0 HugePages_Free:        0 HugePages_Rsvd:        0 HugePages_Surp:        0 Hugepagesize:       2048 kB DirectMap4k:       92096 kB DirectMap2M:     9345024 kB   # uname -a Linux hostname 3.10.0-693.21.1.el7.AV1.x86_64 #1 SMP Thursday April 5, 2018 09:26:08 MDT x86_64 x86_64 x86_64 GNU/Linux   Well, kernel.shmall parameter has the same value.  $ sysctl -a | grep shm kernel.shmall = 18446744073692774399 kernel.shmmax = 18446744073692774399 kernel.shmmni = 4096   Thanks in advance!

I'm just wondering where these values are being set and what they default to? Mine is currently 18446744073692774399. I didn't set it anywhere that I can see.  $ cat /proc/sys/kernel/shmmax  18446744073692774399  $ sysctl kernel.shmmax kernel.shmmax = 18446744073692774399


I am figuring out how I could make the following query more secure: I have already used mysqli_real_escape_string but i doubt that adds much to security.  I have looked into the following:   but I also have to take into account the following line:      $check_customer = mysqli_num_rows($run_c);    Below are the codes     $c_email = mysqli_real_escape_string($con,$_POST['email']);         $c_pass = mysqli_real_escape_string($con,$_POST['pass']);         $couponCodeLogin = mysqli_real_escape_string($con,$_POST['couponCodeLogin']); $couponCodeLoginAmount = mysqli_real_escape_string($con,$_POST['couponCodeLoginAmount']);          $sel_c = "select * from customers where customer_pass='$c_pass' AND customer_email='$c_email'";          $run_c = mysqli_query($con, $sel_c);         $check_customer = mysqli_num_rows($run_c);          if($check_customer==0){          echo "<script>         document.getElementById('loginError').innerHTML = 'Password or email is incorrect, please try again.'         </script>";         exit();         }           if($check_customer>0){                     $crs_id = $_GET['crs_id'];       $insert_c = "insert into customers (customer_email,coupon_code_login,coupon_code_login_amount) values ('$c_email','$couponCodeLogin','$couponCodeLoginAmount')";                 $run_c = mysqli_query($con, $insert_c);                    $_SESSION['userCoupon'] = $_POST['couponCodeLoginAmount'];          $_SESSION['customer_email']=$c_email;                          $_SESSION['userCouponName'] = $_POST['couponCodeLogin'];           echo "<script>window.open('coursePayment.php?crs_id=$crs_id','_self')</script>";          }         else {         $_SESSION['customer_email']=$c_email;            echo "<script>window.open('coursePayment.php?crs_id=$crs_id','_self')</script>";          $_SESSION['userCoupon'] = $_POST['couponCodeLoginAmount'];                 $_SESSION['userCouponName'] = $_POST['couponCodeLogin'];          }     }   and          $fname= mysqli_real_escape_string($con,$_POST['fname']);         $lname = mysqli_real_escape_string($con,$_POST['lname']);         $email = mysqli_real_escape_string($con,$_POST['email']);         $pnumber = mysqli_real_escape_string($con,$_POST['pnumber']);         $couponCodeRegister=mysqli_real_escape_string($con,$_POST['couponCodeRegister']); $couponCodeRegisterAmount = mysqli_real_escape_string($con,$_POST['couponCodeRegisterAmount']);          $pass = mysqli_real_escape_string($con,$_POST['pass']);         $cname = mysqli_real_escape_string($con,$_POST['cname']);         $cposition = mysqli_real_escape_string($con,$_POST['cposition']);            $insert_c = "insert into customers (customer_fname,customer_lname,customer_email,customer_number,customer_pass,customer_cname,customer_cposition,coupon_code_register,coupon_code_register_amount) values ('$fname','$lname','$email','$pnumber','$pass','$cname','$cposition','$couponCodeRegister','$couponCodeRegisterAmount')";          $run_c = mysqli_query($con, $insert_c);            $insert_email = "select * from customers";         $run_email = mysqli_query($con, $insert_email);          $find_email = mysqli_fetch_array($run_email);         $demail = $find_email['customer_email'];               if($email!= $demail)        {          $crs_id = $_GET['crs_id'];           $_SESSION['userCoupon'] = $_POST['couponCodeRegisterAmount'];          $_SESSION['userCouponName'] = $_POST['couponCodeRegister'];          $_SESSION['customer_email']=$email;            echo "<script>          document.getElementById('registerError').innerHTML = 'Account has been created successfully, Thanks!'          </script>";          echo "<script>window.open('coursePayment.php?crs_id=$crs_id','_self')</script>";         }

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


When I write in Hebrew on  (the Stack Exchange site about Judaism) and add punctuation or a point at the end of a sentence, the punctuation will move to the start. For example: "Yesterday I went to the pool." This will become "אתמול הלכתי לבריכה." although it's written in Hebrew from right to left. Can you fix it?

You know, some of us read right to left...  Certain sites like  and  have an obvious need for this, as Arabic and Hebrew are Right To Left (RTL) languages. Many answers on those sites cite the Torah and the Quran respectively. Directly quoting these sources properly requires RTL text.


Buckle up kids, it's story time.. and this is a good one.  So about a week ago I sold my iPhone 6s Plus on eBay to an older couple in Ohio. I erased my phone, made sure it was unlocked from my iCloud account and off it went in the mail. Well sure enough the couple contacted me claiming that the iPhone was "iCloud locked." Seeing as the eBay account had a very high positive feedback rate, I was kind enough to talk to them on the phone to walk through the unlocking process.  Well, that didn't work. They kept claiming it was STILL locked despite me letting them have a modified simple password for my iCloud account for one-time use. So a few days later they got a refund and I got my iPhone back.  After receiving the phone I made sure it was mine. I checked the IMEI number on the box and compared it with the phone. They are the same. I also cross-checked the serial number and is the same serial number. This is in fact the very phone I shipped to them a week ago and it is now back in my possession.  PHEW! So here is where the issue comes in. I booted the phone and connected to my WiFi network to find out that the phone is IN FACT iCloud locked... but not on my account. Instead it is locked to a COMPLETELY FOREIGN iCloud account (email starting with the letter q).  So good god wouldn't you know it, this phone, which is mine, and is verified to by my ORIGINAL PHONE, has been locked by SOMEBODY ELSE (presumably the couple that had the iPhone for a few days).   So here is the deal, I have an iCloud backup of this phone, but I am not sure if it will even let me restore to that (can anyone verify?). I will try this on my own soon and report back as well. I also have this phone under Apple Care+ and have proof of purchase. In a worst case scenario, would Apple allow me to exchange it?  Finally, does anyone have any advice to get me out of this hell?  UPDATE  Ok everyone... the problem just got weirder.  I got the phone back and took it to Apple. I was able to verify the phone was mine and the Apple Genius at the Apple Store unlocked my phone from iCloud and I was on my way. We verified it was completely untied to an Apple account and I re-sold the phone.  Well... the new individual got the phone. And after a day of use, she called me directly and said it was iCloud locked to an account that started with a q. Just like the original buyers. She was more investigative and called Apple, and that is where things got weird.  The Apple representative on the phone looked up the serial number of the phone, and it turns out that during transit from my house to her house, an iPhone with my exact same serial number was checked into an Apple Store in NYC (via mail) and replaced for a cracked screen. The screen replacement came out of my Apple Care+ as well. It appears my SN was somehow duplicated on a different iPhone and this is being abused somehow. If anyone else has experienced this please let me know.

I bought a used iPhone 4.  The previous owner re-set the phone, but did not remove the device from their iCloud.  It is asking me for their iCloud information when I try to set-up the phone.  I don't have contact with the previous owner anymore.  Is there a way to remove the device from their iCloud so I can use a new one?


Using ubuntu 16, updates settings on check every day + download and install automatically.  Please, could you tell me how to check if the updates have been installed? Thanks.

Is there a place where I can look what updates I've installed?


After installing Ubuntu 13.10 I try to install ubuntu-restricted-extras or any software, it shows me:  E: GPG error: http://archive.canonical.com saucy InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication

I can use my mobile broadband to access Internet with Firefox but when I want to install any package from terminal or make 'apt-get update' command I got the following error:  got 'NODATA' (does the network require authentication?)   apt-get update output:  Get:1 extras.ubuntu.com trusty InRelease [213 B] 98% [1 InRelease gpgv 213 B] [Connecting to archive.ubuntu.com] Splitting up /var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_trusty_InRelease into data Ign extras.ubuntu.com trusty InRelease E: GPG error: extras.ubuntu.com trusty InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)    output of `cat /var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_trusty_InRelease  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>404</title> <meta http-equiv="Cache-Control" content="no-cache"/> </head> <body> <p> Not Found </p> </body> </html>   output of wget:  wget -O - http://extras.ubuntu.com/ubuntu/dists/trusty/InRelease  --2014-06-01 09:23:35--  http://extras.ubuntu.com/ubuntu/dists/trusty/InRelease Resolving extras.ubuntu.com (extras.ubuntu.com)... 91.189.92.152 Connecting to extras.ubuntu.com (extras.ubuntu.com)|91.189.92.152|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 213 [text/html] Saving to: ‘STDOUT’   0% [                                       ] 0           --.-K/s              <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>404</title> <meta http-equiv="Cache-Control" content="no-cache"/> </head> <body> <p> Not Found  </p> </body> </html>


I read Kenton Warda's post that the exploit in SSL in most Linux OS's have been patched. Has Ubuntu been patched? What should I avoid doing if it isn't?

NO, this is not a duplicate of . So, read on.  I am seeing conflicting information with respect to Ubuntu 12.04:   The  claims Ubuntu 12.04 to be affected and needs to be patched with 1.0.1g The  claims that version 1.0.1-4ubuntu5.12 for the package libssl1.0.0 should fix the issue on Ubuntu 12.04.   Now I do have these packages installed:  # dpkg -l | grep ssl ii  libssl1.0.0                      1.0.1-4ubuntu5.10                 SSL shared libraries ii  openssl                          1.0.1-4ubuntu5.10                 Secure Socket Layer (SSL) binary and related cryptographic tools  # lsb_release  -a | grep -i description Description:    Ubuntu 12.04.3 LTS   So, If I consider above two points, I am not sure which one is true.  Besides,  says that my machine is vulnerable.  Has anyone yet been able to fix this issue successfully on Ubuntu 12.04? If yes, then could you provide me the steps you have taken?


I have the following:    public static void main(String args[]) {       // upload config' data for program - param' are path and Xml's Root node/ where to get data from      confLoader conf = new confLoader("conf.xml", "config");        System.out.println(conf.getDbElement("dataSource") );      System.out.println(conf.getDbElement("dataSource") );      System.out.println(conf.getDbElement("dataSource") );  // Fails  ...     The code that's responsible to build the DOM and parse from ('getDbElement()'):  public class confLoader{   DocumentBuilderFactory docBuilderFactory;  DocumentBuilder docBuilder;  Document doc;  NodeList nList;   public confLoader(String path, String XmlRoot){      try {             docBuilderFactory = DocumentBuilderFactory.newInstance();             docBuilder = docBuilderFactory.newDocumentBuilder();             doc = docBuilder.parse(new File(path));             // normalize text representation             doc.getDocumentElement().normalize();                     nList = doc.getElementsByTagName(XmlRoot);    } catch (Exception e) {     e.printStackTrace();   }  }  public String getDbElement(String element) {      Node nNode = nList.item(0); //  1st item/node - sql     try {         if (nNode.getNodeType() == Node.ELEMENT_NODE) {     /////  Line 36 - Problematic              Element eElement = (Element) nNode;             return (((Node) eElement.getElementsByTagName(element).item(0).getChildNodes().item(0)).getNodeValue());         }     } catch (Exception ex) {         System.out.println("Error retrieving " + element + " :" + ex.getMessage());//Thread.dumpStack();          ex.printStackTrace();       }     return "not available";  }  }     stacktrace  for given code:    jdbc:mysql://localhost:...   java.lang.NullPointerException   jdbc:mysql://localhost:...   Error retrieving dataSource :null   not available   at exercise.confLoader.getDbElement(confLoader.java:36)   at exercise.Exercise.main(Exercise.java:22)        Line 36 : if (nNode.getNodeType() == Node.ELEMENT_NODE)   The xml parsing is done twice, and for the 3rd time I try to parse from Xml, I get the NullPointerException.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


It seems that it would be a good feature, as future viewers may struggle to follow any mentions in comments after usernames have changed.   Is there a technical reason why it doesn't happen, or is it simply that this feature is relatively low value and therefore hasn't been implemented?   : Ḿűỻịgǻṇącểơửṩᛗ changed their username to Mᛜ. Sᛜ. Rᛜ. require mulligansǃ

The fact that a user can change their name at will can lead to some confusion in the comments.  For instance, suppose a user named "foo" changes his name to "bar", all those comments signed by "foo" are now signed by "bar", but responses to "bar"'s comments still start with "@foo".  Could those "@foo" references in comments be changed to "@bar"?    A brief discussion on this has set me straight.  I didn't think it through.  Request withdrawn.


Can anybody explain  this paragraph from the chapter " Fourier series and transform " of the book  by  M l Boas?     "If you strike a piano key you do not get a sound wave of just one frequency . Instead  you get a  fundamental accompanied by a number of overtones (harmonic) of frequencies 2, 3, 4, ... times the frequency of fundamental".

When you energise a taut string, the following resonant modes of vibration occur:    Plotting on the frequency domain, you can see their corresponding frequencies:    But what is the underlying physical principle? Why does this happen?  Is there any way of explaining it that could be understood by a smart 15 year old?  EDIT: I'm going to give my best attempt so far. Here goes:   We can start with sympathetic resonance. Sounding a particular frequency, a pure sinewave.  And noticing the string resonates sympathetically at the frequency of each harmonic. Say this is explained and understood. Now imagine that plucking a string is equivalent to a burst of white noise, which contains frequencies all the way through the spectrum. This could be approached backwards, by starting with random frequencies and noticing that resultant wave produced looks like white noise.   If the above is scientifically correct, then it restricts the domain of the question.  I would really like to be able to understand it scientifically and also be able to explain it intuitively.  PS Images from


I have a file like this: "Something, something, something, something, something"  And I want to get the index of third "," with:  StreamReader sr=new StreamReader("File.txt"); string s=sr.Readline();     string c=s.Substring(0, s.IndexOf(',')));

Unless I am missing an obvious built-in method, what is the quickest way to get the nth occurrence of a string within a string?  I realize that I could loop the  method by updating its start index on each iteration of the loop. But doing it this way seems wasteful to me.


The answer to this homework problem is $\left(\text{D}\right) :$        I understand why we rule out options $\left(\text{A}\right)$ and $\left(\text{B}\right)$ first. However, I don't get why $\left(\text{D}\right)$ is the answer.  Won't the ball's velocity at one point be $0$ when it comes in contact with the ceiling? (The same way as its velocity momentarily is $0$ when it is thrown downwards and comes in contact with the ground before bouncing back upwards). That should give zero acceleration at that point, but none of the acceleration profiles include $0 .$

I'm studying for my upcoming physics course and ran across this concept - I'd love an explanation.


I want to split each line  by the appearance of  <=> or => So I have 2 delimiters and each of them has more than one character    string example="A + B => C + D";   vector <string> leftRight;   boost::algorithm::split_regex( leftRight, example, boost::is_any_of( " <=> +| => " ));   my expected result is something like this:  leftright[0]= A+B leftright[1]= C+D

I'm trying to iterate over the words of a string.  The string can be assumed to be composed of words separated by whitespace.  Note that I'm not interested in C string functions or that kind of character manipulation/access. Also, please give precedence to elegance over efficiency in your answer.  The best solution I have right now is:  #include <iostream> #include <sstream> #include <string>  using namespace std;  int main() {     string s = "Somewhere down the road";     istringstream iss(s);      do     {         string subs;         iss >> subs;         cout << "Substring: " << subs << endl;     } while (iss); }   Is there a more elegant way to do this?


As the title states, I am having trouble with entity teleporting in Minecraft. I know that I am doing it correct as it works in singleplayer, so I figured it would be a plugin that is stopping me from teleporting entities. The command I am using is /tp @e[name=o] ~ ~300 ~, and the plugins on my server are:     AsyncWorldEditInjector, WorldEdit, Installer, VoxelSniper, Skript,   CustomServerMessages, Buycraft, ColoredSigns, Vault, Multiverse-Core,   PermissionsEx, EmptyWorldGenerator, WorldGuard, Tablist, CoreProtect,   ItemRenamer, BuycraftAnnouncer, NoLeafDecay, WildSkript, ProtocolLib,   HolographicDisplays, mcMMO, VoidWorld, Essentials, ArmorStandEditor,   AsyncWorldEdit, EssentialsProtect, AuctionHouse, EssentialsSpawn,   EssentialsGeoIP, WirelessRedstone, EssentialsAntiBuild,   FakePlayersOnline, TitleManager, CraftBook, EssentialsChat   If you know how to fix this or what plugins to remove/disable please inform me. Thanks.

Recently I've been messing around with making a few minigames, and have used a few plugins to help make it easier to create and run them. However, a newer one I'm making requires me to use the /summon command in order to spawn zombies. However, no matter what I put in, I can't spawn hostile mobs. All other entities still spawn perfectly fine. Strangely, the /spawnmob command which comes with Essentials can summon hostile mobs fine. I would rather use /summon since it's more customizable though. Here's a list of plugins I have installed.   Essentials EssentialsChat HolographicDisplays PermissionsEx setspawn [A plugin I have made, just a simple timer] Vault VoxelSniper WorldEdit WorldGuard   Please let me know if you have any ideas on what I'm doing incorrectly or isn't functioning the way it should.


I'm on Ubuntu 14.10.   FF 35 has support form H264 and VP8, but not MSE and VP9. That is ok, and confirmed by youtube html5 page, , as you see the screen #1 here:   FF35 is the stable version installed from official ubuntu repo.   FF 37 (dev edition), downloaded, uncompressed and launched (no ppa), has support for MSE and VP9, a new feature in FF, but H264 is gone. See screen #2 here:   Is there a way to have FF37 "see" the H264 driver?  Thanks.

According the the , h.264 video should now be working in Linux.  It does also say the appropriate gstreamer plug-ins need to be installed.  Does anyone know what these are?    I used this  and the  to verify that h.264 support works in Google Chrome on my Ubuntu 12.04 64-bit, but does not work on Firefox 26.


Consider the following instructor , I had to initialize treeItem and status anyway , but in a overloaded function , I can introduce the id variable as well.  But it looks silly , I shouldn't be doing this in both of the functions , any suggestions ?  Contact () {     treeItem = NULL;     status = offline; }  Contact (const QString & id) {     treeItem = NULL;     status = offline;      this->id = id; }

As a  developer I'm used to running through constructors:    class Test {     public Test() {         DoSomething();     }      public Test(int count) : this() {         DoSomethingWithCount(count);     }      public Test(int count, string name) : this(count) {         DoSomethingWithName(name);     } }   Is there a way to do this in C++?  I tried calling the Class name and using the 'this' keyword, but both fail.


I have 2 array as below :  Array 1 (   [0] => c1   [1] => c2   [2] => c3 )  Array 2 (    [0] => Son    [1] => Daughter    [2] => Son )   Output required :  Array (   c1  => Son   c2  => Daughter   c3  => Son  )   Can anyone please guide to generate this output ? Thank you.

I've got two arrays of the same size.  I'd like to merge the two so the values of one are the key indexes of the new array, and the values of the new array are the values of the other.  Right now I'm just looping through the arrays and creating the new array manually, but I have a feeling there is a much more elegant way to go about this.  I don't see any array functions for this purpose, but maybe I missed something?  Is there a simple way to this along these lines?  $mapped_array = mapkeys($array_with_keys, $array_with_values);


I would like to change the margin with the beginning of the second page simply by using a KOMA-script option: mpinclude=true. It works, if I write at the end of the text on page 1 this line:  \KOMAoptions{mpinclude=true}\recalctypearea{}   But the drawback is a pagebreak exactly where I put this line.   So I'd like to postpone the command to the end of the page. I found the package everyshi, which offers the command \AtNextShipout.   The following MWE does not work, the margin does not change on the second page, but I get the words [current]last as first line of the second page.   Any ideas?  \documentclass{scrartcl}  \usepackage{everyshi} \usepackage{blindtext}  \begin{document} Here is some text. \AtNextShipout{\KOMAoptions{mpinclude=true}\recalctypearea{}}  \blinddocument \end{document}   This MWE is rather short. My file as well uses the packages scrletter and some *.lco customisation.

I am looking for an automated mechanism to change the effective \textwidth at the first pagebreak of a letter in scrpage2. I've tried \afterpage and \nextpage (ideally they would be set within \firsthead), both without success. I do not want to use the geometry package because firstly, IMO scrlttr2 should work with a change of KOMAoptions and friends and secondly, it does not seem to work anyways if used within scrlttr2 and the KOMA layout. Ideas and suggestions are very welcome.   Here's a MNWE. Page 2 and following should have a wider text block than the first page — but doesn't.  \documentclass{scrlttr2}% \usepackage[english]{babel} \usepackage{lipsum,afterpage}% \setlength{\textwidth}{125mm}% \nexthead{%   \global\areaset{170mm}{\textheight}%   \global\KOMAoptions{DIV=areaset}%   \global\recalctypearea% } \afterpage{%   \global\areaset{170mm}{\textheight}%   \global\KOMAoptions{DIV=areaset}%   \global\recalctypearea% } \begin{document} \begin{letter}{Receipient}   \opening{Dear receipient,}   \lipsum[1-6]   \closing{Yours} \end{letter} \end{document}   And BTW, I genuinely think that this is not covered by  and related questions and instead somehow relates to the internals of the KOMA classes.


I am very new to latex and everything seems a little confusing.  I put all my literature into BibDesk. Now I want to    create a bibliography which needs to be in TeXShop for compilation somehow link (?) BibDesk to TeXShop in order for the \cite{abc2001} to work   I am also a little confused about all the differente formats one can save the literature into. I use a lof of information from websites. All of the times there are authors that can be quoted. However, when I add a new entry as website, I only get to enter URL, last checked, year, month, keywords- no author.  Here is another one: Inproceedings. Is the Book Title the placeholder for the name of the conference, making the title the actual article?

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


I am having hard time with a website design in IE. its actually working fine in mozilla, chrome, opera and safari but very messy in IE. so my question "Is there any plugin like firebug for IE"?.

I'm trying to fix some JavaScript bugs. Firebug makes debugging these issues a lot easier when working in Firefox, but what do you do when the code works fine on Firefox but IE is complaining?


I am trying to understand Linux and I am often solving my problems on a case by case basis without actually learning how to come up with the answer myself, which of course, I prefer not to do.   For example I have set a keyboard shortcut to select an area and take  a screenshot of it. Everytime I select an area, it always defaults to /Pictures, and I would like to edit either the default directory or the quick dropdown choices it presents me.   I have found an  as usual, however this time I would like to know how do people normally approach this if there was no answer. Surely there must be a logical set of steps to pinpoint how a terminal command works/where it takes its arguments.   For this particular case, I have looked online for which command Ubuntu uses to take screenshots, which turns out to be import.   So my question is, what is/are the approach(es) to    Find where configuration files / location / code level information (like not how to call it but what it specifically does when it is called) of a terminal command How to find out which terminal command a particular action corresponds to. (Figuring out import is called when I took a screenshot for example)   In other words, how could I have figured this out myself if I had no access to internet, or no one knew the answer? :) I am more interested in the approach/logic, however import in this case would be a good example.   Edit:  I do not think my question is the same with the suggested possible duplicate because I am asking for a way to reach source code if that is possible. In other ways, I am asking for a way to read the source code of a command, and files it uses (for example maybe there is a config file for import function and if I could have found it I would have changed default-save-directory). To clarify even further, the file I am trying to find (if it is possible to find it) a code equivalent to the following pseudo code:  <when run> change mouse pointer to + shape ..wait for a click.. on click -> wait for release.. on release -> take the area between click and release coordinates read config file located at ./config and get default-save-directory variable initialize path to default-save-directory ask user where to save the image   This has to be saved somewhere in the operating system. "That is not possible because ..." (maybe it is in assembly level for example) is also an answer, but use man to get instructions on what this function does is not an answer because I want to understand how it works.   In yet another words, if a linux ninja was to modify import command on his local computer, where would he go, and say add a signature in the pictures saved with screenshot.

I often see things like     read man xyz   For more information read xyz's man page.   see info xyz    so I wonder:   How can I get help on terminal commands generally? What exactly are these man and info pages?   How can I find and view them?


I am trying to use congruence theorems, specifically Euler's Theorem for a proof.

I read somewhere that     $(a^n - b^n)$         It is always divisible by $a-b$.   When $n$ is even it is also divisible by $a+b$.   When $n$ is odd it is not divisible by $a+b$.      and     $(a^n + b^n)$         It is never divisible by $a-b$.   When $n$ is odd it is divisible by $a+b$.   When $n$ is even it is not divisible by $a+b$.      I wonder what's the proof for this.  First postulate is clear. $(a-b)$ would or would not be a factor. Any light on others?


I've just started covering the topic of binding energy in Year 13 at school (final year before University). The definition we've been given of binding energy is that it is the work done when separating a nucleus into its constituent nucleons. Alright so far.  We've also covered nuclear decays, and an example of that we've been given is    where the mass of the Thorium isotope and the alpha particle (constituent parts) is less than the mass of the Uranium isotope (I've checked this - it's true). We were told this was due to the combined binding energy of the products being less than the binding energy of the uranium isotope.  However, this seems to contradict examples I've found on the internet, such as the formation of an alpha particle from 2 protons and 2 neutrons (see ), where the mass of the constituent parts is higher - energy must remain constant, and the alpha particle has a higher binding energy, so the mass-energy must necessarily be lower. This makes sense.  If someone is able to give a clear explanation of why both of these things are true, I'd be very grateful!  Thanks

I’ve been told that a greater binding energy means the nucleus is more tightly bound, and therefore that decreases the mass of the nucleus with respect to its nucleons when separated. But why does a tighter nucleus mean a smaller mass?


Let $K$ be a field, $\bar{K}$ an algebraic closure and $\sigma \in \mathrm{Aut}_K \bar{K}$. Let $F=\{u \in \bar{K} \mid \sigma(u)=u\}$. Then prove $F$ is a field and every finite-dimensional extension of $F$ is cyclic.

I am trying to prove the following proposition:     Let $L$ be an algebraically closed field, $g \in Aut(L)$ and $K=\{x \in L \; | \; g(x)=x\}$. Show that every finite extensions $E/K$ is a cyclic Galois extension.    So far my thoughts have led me to the following:  If $E=K$, then clearly $E/K$ is Galois and $Gal(E/K)=Aut(K/K)=i$, where $i$ is the identity automorphism, so it is trivially cyclic. Assume $[E:K]=n$ for some $n>1$. Since $E/K$ is a finite extension, it is algebraic. Note that if $\beta \in E\setminus F$ then we have the minimal polynomial $m_{\beta}(X)$ over $K[x]$. Since $K$ is fixed by $g$, we know that $g(\beta)$ is also a root of $m_{\beta}(X)$. We can also conclude that $g(\beta)\not \in K$ since $\beta \not \in K$.   Where to take any of these observations, I have yet to determine. I feel I must be missing something elementary, for I cannot see how to conclude this is a Galois extension from here.   Any tips would be greatly appreciated, especially over full solutions.


How to Use: LVIII    By manipulating the death of a human that has influence over another human’s life, that human’s original life span can sometimes be lengthened.    which means you can use the note to extend your lifespan in the example i gave:  have some one get the shinigami eyes by giving them your death note and have them write down your life span then give back owner ship of the death note to you again (use the note to manipulate them into doing so) for example lets say you die 1st arpril 2009 at 1pm  next find some one who will out live you, you could use the person who you manipulated into finding your life span we'll call this person mr.X  write down your own name and have the cause stabbed by mr.X after calling him fat at 1st april 2009 at 1pm  next write down mr.X's name in the death note and the cause of death is a heart attack just before stabbing some one on the streert who called him fat on 1st april 2009 at 12:58pm  now if this would work you should get his remaining life span. Would this work?

Suppose I wrote that I will be killed by a UFO falling from space in the year 2315 while I am lifting.  Will the Note increase my lifespan? In other words, will I still be alive by then?


I managed to be able to make a scan with my HP Deskjet F4210 All-in-One printer and Ubuntu 18.04 thanks to this article:  I followed this advice:  2 Blockquote +50 I had been using HP Deskjet 4535 MFP Scanning feature within Ubuntu 16.04. However after installing 18.04, it didn't worked, as mentioned by Tanama. (While I had fresh installed 18.04, my home directory was same as one I had used for 16.04.) I verified that "hplip" package was installed during 18.04 stock installation, and tried simple-scan, sane-utils, hp-setup, hp-probe and so on. None of those attempts worked. Even Gimp -> Create -> xscanimage didn't helped. Finally, following worked for me. I installed hplip-gui package after going through this URL:  Blockquote Run Dash -> HPLIP Toolbox (HP Device Manager) and configured my device. I had used manual mode to detect device by explicitly providing static IP address I have assigned to my Wireless MFP. After that, use Actions tab within HP Device Manager, and select "Scan". It starts "simple-scan".   Thank you for this! I have been working on this for more than a year to make it work. I can also print, but I haven't found out yet how to make a copy. I do have HP Device manager now. The printscreen shows the menu I can see when I open HP Device manager, and it shows the last installation details of the command 'hp-setup'. Could anyone advice me how to be able to make a copy? Thanks a lot!

Let's assume that one has some HP printer and/or scanner and checked its support status on the corresponding page of HPLIP site - .  So one have the following information: the device Model name, Min. HPLIP Version and Driver Plug-in need.   What should one install to make Ubuntu fully support the HP printer and/or scanner?


The open-source Sinon project  that are versioned per-release. That means that , you might end up at a doc for version 2.4.1, instead of the latest version (whatever that might be).  What would be a good strategy for ensuring that the highest ranked results in Google would always be the current version?  I was thinking of creating a "version" called current (meaning a path for docs starting with /releases/current/) that would either redirect to the latest version, say /releases/v3.0.1/my-sub-doc.html, or be a copy of the latest docs. I would guess doing a HTTP 302 redirect to a new resource every x weeks might hurt SEO, so maybe the last approach would be the better of the two?

The use case is a document which has multiple versions which are all simultaneously available. For example, documentation on a product for each version of that software:   /v1/install-guide /v2/install-guide /v3/install-guide   These are not the same content in the sense that it would be incorrect to specify in the v1 and v2 pages that the canonical URL is v3. If I searched in Google for 'product install guide v2' I'd expect to be able to find v2. Each version of the document would be slightly different but they'd have a lot in common with each other.  So the question is: can I mark up these pages in some way to signal to Google and friends that the latest version (v3) is preferred, so a simple search for 'product install guide' is more likely to show the v3 page instead of the v1 or v2 page?