Novel set in future Middle-East
Book, it follows a guy in a dystopian future
Prove $\alpha \in R[[x]]$ is a unit iff $a_0 \in R$ is a unit I was working with a new C++ developer a while back when he asked the question: "Why can't variable names start with numbers?"  I couldn't come up with an answer except that some numbers can have text in them (123456L, 123456U) and that wouldn't be possible if the compilers were thinking everything with some amount of alpha characters was a variable name.  Was that the right answer?  Are there any more reasons?  string 2BeOrNot2Be = "that is the question"; // Why won't this compile? Can I bind a (large) block of addresses to an interface? I know that the ip tool lets you bind multiple addresses to an interface (eg, ). Right now, though, I'm trying to build something on top of IPv6, and it would be really useful to have an entire block of addresses (say, a /64) available, so that programs could pick any address from the range and bind to that. Needless to say, attaching every IP from this range to an interface would take a while.  Does Linux support binding a whole block of addresses to an interface? Why do electrons move towards anode in the Photoelectric effect experiment? Consider a Photoelectric effect experiment apparatus as shown in Figure 11.1    The variation of photocurrent with the voltage applied across $\mathrm{A}$ and $\mathrm{C}$ is as shown in Figure 11.3.    My question –     Why is the current non-zero even if the voltage is zero?    Consider a situation in which the voltage across the plates is zero. Photons of sufficient frequency strike the outermost surface of the cathode, emitter plate $\mathrm{C}$. Electrons become free from the attraction of nucleus as their net energy becomes positive.  Why I think that there should be no net current?  As soon as photons strike the outermost surface of the cathode(assumed to be $1$ to $10$ atomic diameters thick), electrons become free. Now, as the electrons have kinetic energy, they'll come out of that outermost surface. Now, the electrons(with kinetic energy) should have an equal probability of going in every direction of the surface. So, around half of the electrons should go in the right direction towards the anode and strike it and half should go to the left, trying to penetrate the inner surfaces of the cathode plate.   Now, the electrons which will go to the right will face some field due to the space charge present in the tube but nevertheless, some electrons will definitely reach the anode plate. After they strike with the anode plate, they'll face some resistance but still, some electrons will reach the low resistance copper wires connected to the anode plate and milliammeter.  Now, consider the electrons which go towards left. They'll definitely face resistance from cathode plate but some will still reach the copper wire.  Now, as there is no potential difference applied between $\mathrm{A}$ and $\mathrm{C}$, there is no need of commutator and voltmeter. So, the ammeter is connected in series with the anode plates and cathode plates with copper wires.  Now, if there is steady state current in the circuit, electrons emitted to any one of the sides should dominate over the other. But the number of electrons emitted on both the sides is same, and all the electrons should face the same resistance as the current(electrons) should flow in a closed loop. But if the number and velocity of electrons coming from both the sides are same, there should be no net current. But there is. Why?  Edit –  From the answers of anna v and mmainville, it can be seen that the emission of electrons is dependent on the angle of emission of light.  But still, the question remains. If the electrons emitted towards anode have enough energy to complete the circuit and again reach the holes in cathode despite the resistance in between, the electrons emitted to the left should have enough energy to come to anode plate via copper wires and again get ejected through anode plate by the virtue of their kinetic energy and reach the cathode plate. In this case too, the current should be zero which is not true. Why? How do I keep my character centred on screen? How to run SuperHot at full screen on a Mac? I have SuperHot downloaded through Steam, and am attempting to play it on my 1080p external monitor. It launches , and I don't see a setting to adjust the resolution or switch out of windowed mode.  I'm running a 15" retina Macbook Pro with OS X 10.11.3. I recently upgraded Windows 7 to Windows 10. The biggest issue I have now is that the Windows Search service no longer works, making the Start menu mostly unusable.  If I go to Indexing Options in the control panel I see that Indexing is not running and the list of paths to index is empty.  Going to advanced options, the current index path is empty, and the new path is empty too. This is true even if I try to use the "New Index" button.  Using the troubleshooter won't help since the service doesn't start. If I try to manually start the "Windows Search" service, I get the error  "Error 3: Unable to find specified path" (this is the rough translation, the original message is in my language).  What can I do to find out which path/file is missing ? I tried to check with Process Monitor, but the only file (beside system libraries) the SearchIndexer.exe try to access seem to be c:\ProgramData\Microsoft\Search\Data\Application (everytime the service is started the whole folder c:\ProgramData\Microsoft\Search is deleted and recreated) and C:\Windows\System32\config\systemprofile (which exists).  Edit: all available updates are installed, and issuing      SFC /scannow   Doesn't reveal any issue Known proofs of Wirtinger's Inequality? Best way for a 'forgot password' implementation? Cartesian Product of Two Countable Sets is Countable How do I install libtiff.so.3? When I try to run Maya from the terminal, I get:  error while loading shared libraries: libtiff.so.3: cannot open shared object file: No such file or directory.   How do I solve this?  Note: Maya is a third-party software. Best practice for Rails App to run a long task in the background? How to create the matrix attached that has 2x2 blocks in its diagonal and a square outlining them? Preloading images with jQuery I'm looking for a quick and easy way to preload images with JavaScript. I'm using jQuery if that's important.  I saw this here ():  function complexLoad(config, fileNames) {   for (var x = 0; x &lt; fileNames.length; x++) {     $("&lt;img&gt;").attr({       id: fileNames[x],       src: config.imgDir + fileNames[x] + config.imgFormat,       title: "The " + fileNames[x] + " nebula"     }).appendTo("#" + config.imgContainer).css({ display: "none" });   } };   But, it looks a bit over-the-top for what I want!  I know there are jQuery plugins out there that do this but they all seem a bit big (in size); I just need a quick, easy and short way of preloading images! Buffering GeoJSON file using Python? Symmetric Matrix , Eigenvectors are not orthogonal to the same eigenvalue. I know that the symmetric matrix has orthogonal eigenvectors corresponding eigenvalues. Also, the eigenvectors from the same eigenvalue are linearly independent.  I need an example of symmetric matrix such that the eigenvectors from the same eigenvalue are not orthogonal.  Also, I know that the eigenvalues of the symmetric matrix are real. But , this statement true iff the entries are real numbers.Right? Since the matrix 2x2 $$A=\begin{bmatrix} 1 &amp;i \\  i &amp;1  \end{bmatrix}$$  has non real eigenvalues I want to draw a table and i used the following code  \begin{table}[htbp]  \centering \caption{Ship simulator required inputs} \begin{tabular}{|c|c|} \hline L_{PP},  L_{WL}, L_{OS}, B, T, T_{a}, T_{f}, C_{B}, D_{P}, `\\` Bulbous bow, Number of bosses, brackets, thrusters. &amp; ship particulars `\\` \hline Required speed or propeller rpm, ship course angle &amp; Mission data \\ \hline BN, weather angle, water temperature &amp; Environment \\  \hline \end{tabular}% \label{inputs}% \end{table}%`   the result of this is as shown in figure    How can i complete the right border of the table ??? I used \\ to break the line of first row I am trying to solve an exercise in Shankar's QM book (concretely 4.2.1), and I am asked the probability of each possible value for the operator $L_x$ when the particle is in a certain eigenstate of another operator $L_z$. I understand that I have to "expand" the state vector in the $L_z$ basis, which in this case is just the appropriate eigenvector, and then change the base to that of $L_x$, i.e to write the $L_z$ eigenstate in the $L_x$ base. The problem is that there is just no way of doing it, since the eigenvectors of $L_x$ don't span the whole Hilbert Space.   I thought all quantum operators had a set of eigenvectors that spanned the whole space, am I wrong on that or am I wrong on my algebra? Sorting grid cells in fishnet grid by location and number using QGIS? I am using QGIS 3.2.0 on a Mac (and also have QGIS 2), and I have a fishnet grid (probably created in Arc) that comprises of nearly 2 million grid cells. As a result, every change I make to the attribute table takes hours, so I can't experiment as I would usually.  I need to label each grid cell such that the north-westernmost cell is "1", and the numbers proceed by rows, until the last number goes into the south-easternmost cell. Using the row-number doesn't work, as that's not how the table is sorted. I've done this before, but cannot remember how. Picking a $\delta$ for a convenient $\varepsilon$? I'm studying some proofs in a book from the library  and  unlike my own book, it doesn't prove by showing that a certain expression is striclty less than $\varepsilon$ (given an  appropiate $\delta$ and $\vert x-a\vert &lt; \delta$, etc). Instead, it shows that it's less than some expression involving $\varepsilon$.   E.g. Given $\varepsilon &gt; 0$, we can pick a $\delta &gt; 0$ so $|f(x) - g(a)| &lt;  \text{insert stuff} &lt; k \cdot \varepsilon$ when $|x-a| &lt; \delta$, and thus $f(x) - g(a) \to 0 $ when $x \rightarrow a$.  How does this make sense formally? (Intuitively, I am convinced.)  I don't have much experience with $\varepsilon$-$\delta$ -proofs, so I might be missing something obvious.