Story about old man teleported to the future where earth is under heavy radiation
Science fiction short story: beam transporting people into the distant future
I've been looking around and I can't seem to find an automatic (i.e. buzz- or Twitter-like) way to follow users inside Stack Exchange. Why haven't the developers added such a feature? It could help beginner users follow other beginners with the same interests. We would be able to learn from each others' questions and pitfalls. Also, it would reduce double posting. I'm trying to find the birth certificate of my wife's great grandmother who was probably born in Durban, South Africa in 1884. I'm currently unable to find any online resources for this.  If such a thing does not exist online, is there any other method of retrieving a copy or at least just the details? How to filter by messages, not by conversation? I have been emailing my Gmail account error messages from a project I am working on.   I am trying to use Gmail filters/labels to sort out the class of errors.  But because the subject line is basically always the same even if I have a specific filter for 3 known error cases, the label is applied to the conversation, instead of the specific message.  Therefore, all the errors get all the filters.  I do not yet want to delete the errors, but would rather file them separately.   I have not yet used the NOT contains string yet, but that looks to be non-scalable as I get to the fourth or fifth error case I am done with handling.  Is there any option other than turning off Conversations for all my email?  (I guess I could use one of my spare accounts to turn off conversations and do the work there but would be nice to have such an option). How do I root my Android device? This is a common question asked by those who want to root their phones. How exactly do I root my Android device? Are there risks involved? No cycle containing edges $e$ and $g$ implies there is a vertex $u$ so that every path sharing one end with $e$ and another with $g$ contains $u$ There is a proof in my textbook for the following claim, which doesn't make a whole lot of sense to me.  My annotations are in bold.  Could someone perhaps elaborate on what's going on?  Claim.  If there does not exist a cycle containing edges $e$ and $g$ then there exists a vertex $u \in V (G)$ such that every path in $G$ sharing one end with e and another with $g$ contains $u$.  Proof: The claim trivially holds if $e$ or $g$ is a loop OK, so we assume that neither is. Let $P$ with vertex set $v_1, v_2, . . . , v_k,$ in order, be a path with $e$ joining $v_1$ to $v_2$ and $g$ joining $v_{k−1}$ and $v_k$. Let $f_i \in E(P_i)$ be the edge with ends $v_i$ and $v_{i+1}$. Let $j$ be chosen minimum so that no cycle in $G$ contains $e$ and $f_j$ We can do this because we know that at least the edge $g$ will not create a cycle by assumption, right?. We will show that $u = v_j$ satisfies the claim.  Suppose not. Let $C$ be a cycle containing $e$ and $f_{j−1}$ What if $f_j = e$?  then what cycle? a single vertex? and let $P′$ be a path from an end of $e$ to an end of $f$ Not sure what the book meant by $f$ here, any guesses? avoiding $u$. Choose a subpath $Q$ of $P′$ with one end in $V (C)$ and another in ${v_{j+1}, v_{j+2}, . . . , v_k}$ as short as possible. Then $C \cup Q \cup P$ contains a cycle containing both $e$ and $f_j$, a contradiction. (The last statement requires some case checking.) This ending seems a bit abrupt and non-obvious to me  Thanks for the help Ball swung in a horizontal circle, can the string ever by exactly horizontal to the ground? You swing a ball on the end of a lightweight string in a horizontal circle at constant speed.  Can the string ever by truly horizontal?  If not, would it slope above the horizontal or below the horizontal?  Why? What is the fastest way to get from Courmayeur/Aosta to Milan? We will be crossing the Italian/French border through Mont Blanc via cable cars, which we heard through Rick Steve's article: .  We will be starting off in Chamonix and arriving in Courmayeur. What's the fastest (and relatively cost-effective) way to get to Milan from Courmayeur? Why did Terence Tao write Proposition 2.1.11 about mathematical induction in "Analysis I"? I'm writing an application that allows users to upload images onto the server. I expect about 20 images per day all jpeg and probably not edited/resized. (This is another question, how to resize the images on the server side before storing. Maybe someone can please drop a .NET resource for that in the comment or so).  I wonder now what the best place for storing uploaded images is.   Store the images as a file in the file system and create a record in a table with the exact path to that image. Or, store the image itself in a table using an "image" or "binary data" data type of the database server.   I see advantages and disadvantages in both.  I like a) because I can easily relocate the files and just have to change the table entry. On the other hand I don't like storing business data on the web server and I don't really want to connect the web server to any other datasource that holds business data (for security reasons)  I like b) because all the information is in one place and easily accessible by a query. On the other hand the database will get very big very soon. Outsourcing that data could be more difficult. I am writing a client-side Swing application (graphical font designer) on Java 5. Recently, I am running into java.lang.OutOfMemoryError: Java heap space error because I am not being conservative on memory usage. The user can open unlimited number of files, and the program keeps the opened objects in the memory. After a quick research I found  and others saying on Windows machine the JVM defaults max heap size as 64MB.  Given this situation, how should I deal with this constraint?  I could increase the max heap size using command line option to java, but that would require figuring out available RAM and writing some launching program or script. Besides, increasing to some finite max does not ultimately get rid of the issue.  I could rewrite some of my code to persist objects to file system frequently (using database is the same thing) to free up the memory. It could work, but it's probably a lot work too.  If you could point me to details of above ideas or some alternatives like automatic virtual memory, extending heap size dynamically, that will be great. Can't unhide objects PATH variable resets with reboot Just as the title indicates my PATH variable resets after every reboot. I read that I have to edit my bashrc file's PATH variable, but I don't have anything there that suggests anything related to the PATH variable. Can't redirect cut output PHP function substr() error I'm interested in Gaussian blur layer that blurring all inside of some figure located on this layer.  I mean, blurred background of some exact area. And in case of I move this area, blurred image must be updated. If I move some object in background - blur must be updated. etc. For every prime of the form $2^{4n}+1$, 7 is a primitive root. I am looking for a way to identify primitives types in a template class definition.  I mean, having this class :  template&lt;class T&gt; class A{ void doWork(){    if(T isPrimitiveType())      doSomething();    else      doSomethingElse();  } private: T *t;  };   Is there is any way to "implement" isPrimitiveType(). Google Chrome: Have different settings on different computers? Real Analysis - Prove a set is countable I am asked to prove the following question:  For each finite set of real numbers, $F$, define $\sum F$ to be the sum of all the numbers in $F$.  For each set $P$ of positive real numbers, define $\sum P=\sup\{\sum F: F\text{ is a finite subset of } P\}$.  Suppose $P$ is a set of positive real numbers such that $\sum P &lt; \infty$. Prove that $P$ is a countable set.  My attempt (just a sketch proof):  Suppose $P$ is uncountable, $\exists \epsilon_1 &gt; 0$, s.t. $$ P_1 = [\inf P + \epsilon_1, \sup P]\cap P $$ is uncountable. Pick $a_1 \in [\inf P, \inf P + \epsilon_1] \cap P \in P$, such a $P$ must exists due to greatest lower bound property.  Now $P_1$ is uncountable, $\exists \epsilon_2 &gt; 0$, s.t. $$ P_2 = [\inf P_1 + \epsilon_2, \sup P_1]\cap P_1  $$  is uncountable. Pick $a_2 \in [\inf P_1, \inf P_1 + \epsilon_2]\cap P_1 \in P$. Carry on this process (this should be formalized using induction), we can find  $$ a_1 \leq a_2 \leq a_3 \leq ... $$ with $a_n &gt; 0$ and $a_n \in P$ for all $n$.  Now $\sup\{\sum F_n: F_n = \{a_1,...,a_n\}, n \in \mathbb{N}^+\} = \lim_{n \to \infty}\sum_{i = 1}^n a_i &gt; \lim_{n \to \infty}na_1 = \infty$. This means that $\sum P = \infty$ since $\{\sum F_n: F_n = \{a_1,...,a_n\}, n \in \mathbb{N}^+\} \subset \{\sum F: F\text{ is a finite subset of } P\}$.  I think my proof is a bit clumsy but is it correct? Find $\space\ \begin{align*} \lim_ {x \to+\infty} \left [ \frac{\log_{2}(x-1)}{x}\right]   \end{align*}$.   After some minutes around this limit I did it this way:  $\log_{2}(x-1)=y \Leftrightarrow 2^y=x-1$  So,$\space x=2^y+1$.  When $x \to +\infty$,$\space y \to +\infty$ also. By substitution:  $\begin{align*} \lim_ {y \to+\infty} \left [ \frac{\log_{2}(2^y+1-1)}{2^y+1}\right]=\lim_ {y \to+\infty} \left [ \frac{\log_{2}(2^y)}{2^y+1}\right]=\end{align*}$  $\begin{align*}\lim_ {y \to+\infty} \left [ \frac{y}{2^y+1}\right]=\lim_ {y \to+\infty} \left [ \frac{1}{\frac{2^y+1}{y}}  \right]=\lim_ {y \to+\infty} \left [ \frac{1}{\frac{2^y}{y}+\frac{1}{y}}\right]= \frac{1}{+\infty+0}=0  \end{align*}$  Is this correct?Are there any other easy way to find this limit?Thanks