Why zero is a multiple of every integer, but not a divisor of zero?

All positive and negative numbers including zero are called integers. So in the form $a=bq$, since $0 = 0ㆍq$ is true for any integer $q$, $0$ can have $0$ as a divisor of itself as well as a multiple of itself by the definition expressed by $a=bq$.   But why it's said "We cannot divide by $0$"? It's understood as "$0$ cannot be a divisor" to me.  "Definition: An integer a is called a multiple of an integer $b$ if $a=bq$ for some integer $q$. In this case we also say that b is a divisor of $a$, and we use the notation $b | a$ . . . On the other hand, for any integer $a$, we have $0 = aㆍ0$ and thus $0$ is a multiple of any integer."   Source: Abstract Algebra: Third Edition, John A. Beachy, William D. Blair, p.4.  "Rule Division by $0$ is undefined. Any expression with a divisor of $0$ is undefined. We cannot divide by $0$"   Source: Prealgebra: A Text/Workbook, Charles McKeague, p.61.  "Observe that division by the integer $0$ is not defined, since for $n≠0$ there is no integer $x$ such that $0ㆍx=n$ and since for $n =0$ every integer $x$ satisfies $0ㆍx=0$"   Source: Introduction to Mathematical Proofs, Second Edition, Charles Roberts, p.99.  [Now I understand my question more after reading number theory chapter of a book]  $0=d\cdot 0 $ Thus, 0 is a multiple of every integer except 0.


In AES is 0x11b is the specified field generator?

As I know all arithmetic operations in AES are done over $GF(2^8)$ so I want to know which field generator AES uses? is it 0x11B? and choosing another field generator would it give a different results?


Connections on vector bundles: how they allow us to differentiate sections and to identify fibers?

A connection $\nabla$ in a vector bundle $E$ over manifold $M$ is a (globally defined) map $$ \nabla : \Gamma(E) \to \Gamma(T^* M) \otimes \Gamma(E) $$ that satisfies the Leibniz rule: $$ \nabla(f \, s) = \mathrm{d}f \otimes s + f \nabla s $$ I often heard that in vector bundles, a connection gives us a way to identify nearby fibers, so we can differentiate sections, however I don't how this works using the above  definition. Could any one please explain how a connection allows us to identify nearby fibers and to differentiate section ? Your help would be greatly appreciated!


What effect does Power Word Kill have on a critically injured Wild Shape Druid?

The Player's Handbook states that when a Druid in Wild Shape loses all of its hit points, it reverts to Druid form.  What would happen if an enemy Wizard casted Power Word Kill on the Wild Shape Druid?  Do you use the Druid's hp or the Wild Shape's hp to determine if the spell can work?  And if it does, is the Druid kill outright,  or does it just revert back to Druid form?


Speed of one frame with respect to another in special relativity

To derive the Lorentz transformation we begin with the general relationship between two frames as below: $x' = Ax + Bt$ $y' = y$ $z' = z$ $t' = Cx + Dt$  If frame $S'$ is moving at speed $v$ with respect to frame $S$, how can we say that the speed of frame $S$ with respect to frame $S'$ is $-v$ ? (There is a similar question here. One answer has made up his own theory as people have commented there and ended up with negative votes the other one uses four vectors which is unnecessary since this question is  elementary for special relativity and indeed the textbook doesn't even mention four vectors in the derivation of Lorentz transformations. )


How do I ask a professor at a different department whether I can attend his classes?

There is a professor in Department X. I will be applying to Department Y & Department Z for a MA that really fits my interests. Now, I am wondering whether the professor in Department X will also hold classes in Department Y & Z, or whether these classes are shared and accessible over multiple departments anyways (how does this usually work in the UK? I don't really know). How do I ask him this question, how do I best phrase it? I am a bit unsure about this. Right now I have  I am currently thinking of applying for X at Uni X, and am wondering whether I could then attend your courses too?   but it sounds a bit strange to me? (English is not my native language)


Tauriel and Kili relationship: Can a dwarf and an elf reproduce?

The title sums it all, I just am seeking an answer in the Middle Earth world, not the Tolkien nor the Peter Jackson's world. I believe it is already a singularity to find a dwarf attracted to an elf and vice versa. So is it possible for the two breeds to reproduce? If it is, what can the outcome be? A hybrid, and dwarfish elf or an elvish dwarf?  Please do excuse my lack of knowledge of the middle earth, I only watched the movies and didn't have the chance to read any written material about it, so if this is a redundant question, just let me know.


Why is /24 used in /etc/network/interfaces when configuring static IPs?

My understanding is that 10.0.2.1/32 means 10.0.2.1 vs 10.0.2.1/24 means 10.0.2.1 to 10.0.2.255. For example in /etc/network/interfaces, /24 is used when configuring static IPs. But in /etc/iptables/rules.v4, -d 10.0.2.0/24 means any IP in the 255.255.255.0 subnet... which equals 10.0.2.0 to 10.0.2.255 right? Sorry for the newbie question... I am confused!


Enable Answer @replies to operate like Comment @replies

When a user posts an answer to a question and uses "@user" the user to whom they refer doesn't get a Notification, unlike  which does alert the user about the post.  It would seem that if the answerer makes a point of writing @user in his answer (possibly referring to another answer or comment) that they intended to notify that person, otherwise they could have wrote the user's name without the at symbol.


I want to run sudo ifconfig lo0 alias someIp every time I open my mac, what would be the best way to achieve this?


Show that if $f : G → H$ is a homomorphism, $ H$ is abelian and $ N $ is a subgroup of $G$ containing $Ker f$, then $N$ is normal in $G$

Show that if $f : G → H$ is a homomorphism, $H$ is abelian and $N $ is a subgroup of $G$ containing $Ker f$, then $N$ is normal in $G$.      (First Isomorphism Theorem) If $f: G→ H$ is a homomorphism of groups, then $f$ induces an isomorphism $G/Ker f\cong Im f$.      Corollary 5.12. lf $N$ is a normal subgroup of a group $G$, then every subgroup of $G/N$   is of the form $K/N$, where$ K$ is a subgroup of $G$ that contains $N$. Furthermore, $K/N $ is normal in $G/N$ if and only if $K$ is normal in $G$.   Proof: Since $H$ is abelian, $f(H)$ is an abelian subgroup. (How?) By the First Isomorphism Theorem $f(H) \cong G/Ker f$ (How?), and so it too is abelian. (How?) Thus for every $g ∈ G, n ∈ N$, $$(gH)nH(g^{-1}H) = (gH)(g^{-1}H)nH = nH.$$  Therefore $(gH)(N/H)(g^{-1}H) = N/H $ and so $N/H$ is normal in $G/N$. From here Corollary-I.5.12 concludes $N$ must be normal in $G $ since $N/H$ is normal in $G/Ker f$.  Can anyone explain the (How?) parts ? Or is there any other proof suggested, since I understood so little from this.


How to sum a range of cells with N/A values?

I have a range and need to sum it using SUM function but the result is N/A if there is any N/A value. How can I make the SUM function to treat the N/A value as 0 value?  Please help!


Add syntax highlighting for the MATLAB language

MATLAB language posts don't look good under google-code-prettify.  As far as I understand from  post, MATLAB is currently highlighted by using the default language syntax.  For example, you can see  question. Since % is the standard in MATLAB to write comments, but it is not known, comments look weird.   However, it has an option to write a custom .js that defines a new language. I was thinking about writing myself a custom .js that will do the trick, but before I do that, I want to make sure that it will actually be used in Stack Overflow, and my effort is not in vain.  Is it possible to add custom google-code-prettify .js files to the server of Stack Overflow?


I was browsing through my old textbook and I found this problem:  Find Derivative of $ x^x$  My work :  Haven't got a clue yet, where to start?


Edit help overlays on the footer in edit

Not sure if it is reported, but I couldn't find any.  So, in edit page for questions/answers, when we scroll down, the help on the right will overlay on the footer.   I am not sure if it is a bug or feature, but it doesn't look friendly to me anyway.


What's the effect of "int a(); " in C++?

What's the effect of int a(); in C++?  Is it equivalent to int a or int a(0)?  And how about char c() and double d()?


Can you help me with my software dependency issue?

This is a  about Compile Dependencies and Package Management.    I have a question regarding compiling ports/software or installing RPMs on my *nix server.  When I try to do this I receive lots of messages about missing dependencies.  Can the Server Fault community please help?


Length of latus rectum of parabola given the equation of the tangent to the parabola, the point of tangency and focus

Problem Statement:- Let $y=3x-8$ be the equation of tangent at the point $(7,13)$ lying on the parabola whose focus is at $(-1,-1)$. If the latus rectum of parabola is $k$ then find the value of $\lfloor{k^2}\rfloor$.  I could not think of much on this, but I did the find that the image of focus of the parabola w.r.t any tangent lies on the directrix by messing around in geogebra. Some hints to this problem would be great.


Why is $x^n \psi^{(m)}(x)$ zero at infinity?

Prove: Product of any polynomial of $x$ with $\psi(x)$ or any of its derivatives goes to zero in the limit $x\to\pm\infty$.   This comes from a footnote written by the professor in his quantum mechanics problem set and I am curious to know why. I have unsuccessfully attempted L'Hôpital, Taylor expansion, and many other weird methods. Any help is appreciated.


Will a tube smaller than the tire be compatible?

I have a e-scooter with 10" by 2.50" wheels that needs a tube. Will a 10" by 2" tube be compatible with the tire? Or do I need to purchase one with the same size as the tire? Please let me know. Thank you


How can I prove $\sum\limits_{n=2}^{\infty}\frac{\zeta(n)}{2^n}=\ln(2)$?

Playing with values of $\zeta(n)$ in excel I find those two interesting results $$\sum\limits_{n=2}^{\infty}\frac{\zeta(n)}{2^n}=\ln(2)$$ $$\sum\limits_{n=2}^{\infty}\frac{\zeta(n)}{(-2)^n}=1-\ln(2)$$ How is it obvious? How can I prove it?


Is it possible to use linear model $Y=aX_1+b(X_1\times X_2)+c$?

I am doing linear regression with SPSS. There are two potential Predictors $X_1$ and $X_2$ for Dependent Variable $Y$. I found that $X_1$ and $X_2$ are strongly correlated $(r=0.63, p<0.001)$. So I induce the interaction term $X_1*X_2$. However, I found the Model 1,   $Y=a_1X_1+a_2X_2+b(X_1\times X_2)+c$, $(\text{sig.}=0.098)$   is less significant than Model 2,   $Y=aX_1+b(X_1\times X_2)+c$,  $(\text{sig.}=0.040)$,   and the standardized coefficients of $X_2$ in Model 1 are near $0$ $(\text{sig.}=1.000)$. Since $X_1$ is the main predictor I am interested, could I use Model 2 instead of Model 1?


Let X be a set with an associative binary operation ◦ with identity e. Suppose every element of X satisﬁes x ◦ x = e. Prove that ◦ is commutative.

I'm having problems trying to figure this out. It seems very straight forward, but I don't know what I should do to prove it. Let $X$ be a set with an associative binary operation $\circ$ with identity $e$. Suppose every element of $X$ satisﬁes $x \circ x = e$. Prove that $\circ$ is commutative.


I'm trying to write a \newcommand for verbatim:  \newcommand{\codeline}[1]{\begin{verbatim}{#1}\end{verbatim}}   and use it as  \codeline{int foo;}   but it gives an error "File ended while scanning use of \@xverbatim". How to fix it?


I want to prove that $x^2+y^2+xy\ge 0$ for all $x,y\in \mathbb{R}$.  My "proof":  Suppose wlog that $x\ge y$, so $x^2\cdot x\ge x^2\cdot y\ge y^2\cdot y=y^3$ (because $x^2\ge 0$ so we can multiply both sides by it without changing the inequality sign) giving $x^3\ge y^3$. Substracting we have $x^3-y^3\ge 0$ or $(x-y)(x^2+xy+y^2)\ge 0$. Since $x\ge y$ we can divide by $x-y$ to get $x^2+xy+y^2\ge 0$.  Is it right?  Thanks for your help!


How can the action can describe a movement? What is the argument behind?

We define the action of a system as $$S(q)=\int_{t_1}^{t_2}L(t,q(t),q'(t))dt,$$ where $q(t)$ is the evolution of the system and $L$ is the Lagrangien. How can a stationary point of $S$ can describe the mouvement of a system ? So, how did we arrive at :  if $q$ is a stationary point of $$\int_{t_1}^{t_2}(T-V)(t,q(t),q'(t))dt,$$ then $q(t)$ describe the mouvement... (where $T$ is the kinetic energy and $V$ the potential). How did we arrived to that ? It looks so magic for me, I would like to understand a bit better the motivation behind.


Basically what I wanted was to create a session with an expire time of 24 hours. And I wrote this:  session_start(); if (!isset($_SESSION['TIME_START']) || $_SESSION['TIME_START'] < time()) {         $_SESSION['TIME_START'] = time(); } else if ($_SESSION['TIME_START'] > 60 * 60 * 24) {     session_destroy(); }   I would like to know if this is a valid, viable or good practice to do it. Thanks!


Here's my issue, mostly with privacy:   I connected all my SE accounts long ago but recent events have made it much easier to jump from my profile here to my profile elsewhere. I have questions on site A that I'd rather not be associated with my "identity" from site B. I have no way to delete a question on site A since it has been answered and I have no way to anonomize it for privacy concerns.   Is there a way to:   Delete the question Anonymize the question Unlink my account from site A?


How do I make a progress bar with letters that get "filled in"?

I want to make a progress bar made of text! I have two images: One with the text in gray, the other coloured:     As my game is loading, I want the letters to "fill up" with color:    They would start out gray, then fill in.  I was thinking of overlaying a transparent rectangle over the gray image, then stretching the transparent rectangle to match the progress. But then the background will be coloured too. I want only the letters to be coloured!  How can I do this?


Setting up my vhosts file correctly in WAMPServer

I am trying to setup an mobile app that I have received from another dev locally on my machine, this is a cordova based mobile app that is basically html5/javascript etc..  I have added the following line to my .hosts file:  127.0.0.1 app.myapps.local 127.0.0.1 localhost # existing line has always been there #   In my version of WAMP my virtual hosts are found within the following directory:  C:\wamp\vhosts\local.conf   In my virtual hosts file (there are lots of existing vhosts in there) I have added the following new addition  <VirtualHost *:80>   ServerAdmin me@website.com   DocumentRoot "c:/wwwroot/app/App/www/app.html"   ServerName app.myapps.local <Directory "c:/wwwroot/app/App/www/app.html">     Options +Indexes     AllowOverride All </Directory>   ErrorLog "c:/wwwroot/app/log/error.log"   CustomLog "c:/wwwroot/app/log/access.log" common   LogLevel debug   SetEnv MANGO_ENVIRONMENT ME </VirtualHost>   I have restarted apache and flushed the dns but for some reason everytime I load up app.myapps.local in the browser I am presented with the default WAMPSERVER homepage.  Can anyone suggest what could be wrong in my setup?  -- UPDATE -- I have noticed that app.myapps.local seems to behave like an alias to http://localhost for some reason, for instance I have test website with the local url of localhost/test however if I do app.myapps.local/test I get the same content as localhost/test.  Any ideas on why this is happening?


How to do shortcut bat files to choose the next login OS - dual boot 7 and 8

I have dual boot Win 7 Pro 64-bit and Win 8 Pro 64-bit on a Dell Optiplex 7010 MT.  How can I write two batch files on the desktop of EACH OS to tell it to reboot either into Win 7 or into Win 8.  (Four batch files total, two on each desktop.)  Need it because I frequently remote into this machine and have no way of rebooting efficiently into the desired OS.  I could use in each OS: System Properties - Startup and Recovery - Settings - System Startup - Default Operating System but it just takes too long to go there, make the setting and then do restart.  I'd like some batch files that do all of that for me.  Thanks!!


If a player takes control of your , then it dies while they control it, do they also get the tokens it creates?


Can I re-enter Thailand the day my permit expires, and get a new one?

I am from Italy and as such I have a 30bdays exemption visa to enter thailand. This will be valid until the 21st of February. Tomorrow 16th of February I will leave Thailand for Malaysia, but I plan to go back to Thailand on exactly the 21stand stay till the 28th of February. Will I get a new 30 days exemption permit, even if I am still within the limit of my previois permit?


A friend of mine has the following problem.  She booked a flight from Finland to Denmark she discovered now (she is supposed to fly tomorrow) that her passport is expired and for some reasons she does not have her ID card with her. She only have a driving licence.  Is it still possible for her to take the flight?   Any help will be very appreciated!


Is it possible to use Oracles Java 7 in general instead of apples Java 6?

i have recently bought my first rMBK and i really love it. i would like to start programming in java and have therefore tried installing two IDEs, eclipse and NetBeans. i have also made sure to download the newest java version from oracle (7u45). my problem is that the java provide from oracle is not used in eclipse and i cannot even install NetBeans - it stops installation and ask me to install java 7, even though it should already be installed. i am running OS 10.9.1. typing "java -version" gives the output:  java version "1.6.0_65" Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609) Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)  and "which java" gives "/usr/bin/java". under "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java" i can find the java version from oracle - but it is not the version used for anything except browser plugins. typing  "/Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java -version"  java version "1.7.0_45" Java(TM) SE Runtime Environment (build 1.7.0_45-b18) Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)  i guess i can change the config file for eclipse, so that it uses the java in the strange "internet plugin" folder but for simplicity i would prefer if i could put Oracles java in my /usr/bin/ folder so all programs automatically uses the newest release. it would also allow me to install all the programs/aps that requires the newest java. renaming apples java to "java_backup" and copying oracles java to the usr/bin folder does not work. would it make sense to update my path variable to include the strange "internet plugin"? i have previously made a mess by adding strange folders to my path environment on linux so i am a bit cautious about that.


How to improve the prediction accuracy ofa LSTM model

I am trying to learning the LSTM method by training the model on a custom dataset. This dataset has 6000 vectors of size 7. The 85% of the 6000 vectors are used for the training and the rest for the validation. In each vector the first value is the input (input_dim=1) and the rest 6 values are the output (output_dim=6). The structure of my network looks like this: model = Sequential() model.add(LSTM(10, input_shape=(1, look_back),return_sequences=True)) model.add(TimeDistributed(Dense(6,activation='linear'))) model.compile(loss='mean_squared_error', optimizer='adam') history= model.fit(trainX, trainY, validation_data=(testX,testY), epochs=200, batch_size=10, verbose=2) model.summary()  As you can see below in plots showing the validation result and training process, respectively, the training has "succeeded". Although I can not manage to train the model to perfectly predict the validation output. Am I missing here something or could you give me some tips to improve the accuracy?


Show Log of the Sql statements that QGIS generates to retrieve Data from Postgis

Is there a ways to  - make QGis log its generated SQL Statement or to - force POSTGIS to log all interaction with QGIS?  There is something strange happening to the WFS layer I retrieve in QGIS, since it does  not select all data available in the respective database table. I need to find out, what criteria QGIS chooses in order to narrow down the select set.


Spatially joining polygon fields onto point layer in QGIS?

I have gridded depth points in CSV format that I'm trying to add other map data to, in additional columns. I've tried joining fields, hoping that I could link the Shapefile data to the csv, but when I try to display the csv by graduated symbols based on the new fields, it goes blank. I used Nathan's tips from , but imported the csv as csv since I want to add map info to that, rather than adding csv info to a map.  See this picture below for the sea bottom temperature & salinity voronois by month, underneath the csv points (a sample subset), with the joins already made. I added columns on the csv for each of the fields i'm intending to append.    I also tried spatial joins as per  however it says the layers aren't the same CRS (I checked, they are), then gets to 15% and hangs.  I also also tried spatial join through  but it hit a python error. I can try this again and look to debug the problem if this is the right way to go.  In short: appending polygon data as fields on a points-grid csv: what's the best way in QGIS 2.0?


Is there an iconic monster or creature for each alignment?

In my D&D 5e game, I have a custom cosmology, and I'm currently working on a concept for an afterlife plane where any sentient creature who enters is sorted by alignment and guided to the afterlife. While in this afterlife plane, a character begins to take on a form that represents its alignment. This visually distinguishes each alignment from one another (making them easier to sort) but also provides a cool transformative aesthetic that my players have expressed interest in seeing.  In order to prevent this from being opinion-based, answers must entail specific monsters that have canonically been declared to be representative of their respective alignment, or creatures that have another narrative connection with their alignment or alignment-based plane. I will accept any creature from the history of D&D and Pathfinder as long as you can cite its close ties with its respective alignment.  I understand that there may be more than one correct answer (for example, Monster X may be the perfect NE monster in D&D 4.0 while it might be Monster Y in Pathfinder. An answer is considered correct as long as it is backed by the lore of its system.


What would have happened if all of Voldemort's Horcruxes were destroyed before he returned to physical body?

As the question states, if all of Voldemort's Horcruxes were destroyed and only his mangled spirit that flew to Albania remained, could he have returned to physical body?


Converting x,y coordinates (EPSG:102002) to latitude,longitude (EPSG:4326)

I have ranges of x and y coordinates in EPSG:102002 GRS 80 that I need to convert into EPSG:4326 WGS 84. I have tried different suggestions  and  but nothing has worked so far. I find myself manually converting points of x and y coordinates to lat and lon coordinates online, one point at a time (N = 8200). Is there a way to automatize this process where it also takes the projection into consideration? I am pretty flexible with the program using, as long as it is not ArcGIS and Java. Here is a sample x             y            lat       lon -3145588.03  5018975.86   63.30     177.62 -3115010.95  5010633.39   63.55     177.94 -3084474.59  5002315.52   63.80     178.28


Definition of residuals versus prediction errors?

I always thought the definition of residuals is the difference between the statistic and the observations.  And, the definition of the prediction error is the difference between the true value and the prediction.    So, I was surprised when I saw on  wikipedia page it says   "...while lower-case y in the definition of the residuals..."  under the section called "Residuals" and the sub-section called "Example".  It seems to be showing the error because the lower case "y" is the true value, but it calls them the "residuals".  Is that incorrect to call them "residuals"?


I have a problem with coloring a area with three restrictions. The area I want to color is between the points: (0,0), (0,1.5), (2,1.5), (2.5,1.25), (2.5,0), (0,0). As you can see I've managed to do something but no matter what I try either the big triangle or the little one will be colored. I hope you can help.   \begin{tikzpicture}  \begin{axis}[     axis lines = left,     width=10cm, height=8cm,     ymin=0,     xmin=0,     ymax=3,     xmax=6,     xticklabels={,,},     yticklabels={,,},     clip=false ]    \addplot[smooth][domain=0:5, color=black,line width=0.4mm]{1.5};  \addplot[smooth][name path=f,domain=0:5, color=black, line width=0.4mm]{(5-x)/2};      \addplot[smooth] coordinates {(2.5,-0.1) (2.5,3)} [color=black, line width=0.4 mm]; \path[name path=axis](axis cs:0,0) -- (axis cs:2.5,0); \addplot [     thick,     color=brown,     fill=blue,      fill opacity=0.5 ] fill between[     of=axis and f,     soft clip={domain=0:2.5}, ];    \node at (axis cs:-0.3,-0.3){$(0,0)$};   \node at (axis cs:2.5,-0.3){$(2.5,0)$};   \node at (axis cs:5,-0.3){$(5,0)$};   \node at (axis cs:-0.6,2.5){$(0,2.5)$};   \node at (axis cs:1.7,1.3){$(2,1.5)$};   \node at (axis cs:3.2,1.7){$(2.5,1.5)$};   \node at (axis cs:3.3,1.25){$(2.5,1.25)$};   \node at (axis cs:-0.6,1.5){$(0,1.5)$};  \fill (0,0) circle[radius=2pt]; \fill (2.5,0) circle[radius=2pt]; \fill (5,0) circle[radius=2pt]; \fill (0,2.5) circle[radius=2pt]; \fill (2,1.5) circle[radius=2pt]; \fill (2.5,1.5) circle[radius=2pt]; \fill (2.5,1.25) circle[radius=2pt]; \fill (0,1.5) circle[radius=2pt];  \addplot[dashed][domain=-1/2:1/2, color=black, line width=0.4mm]{-x/3}; \end{axis} \end{tikzpicture}


There are historically locked posts (such as ) containing offensive answers (such as ).  I am not interested in flagging the question for deletion -- a moderator already decided that it's a bad question that should stay anyway. But being locked doesn't mean the answers are all "not offensive" or even "not spam".  I propose that locked posts lose their immunity to spam, offensive, and custom-reason flags.


I am planning on getting my first DSLR soon. I'm torn between the 1300D and 650D because they are about the same price right now. I love the fact that the 650D has a movable touchscreen and a mic input, but I'm not sure if buying a nearly 7-year-old model over the 2016 1300D is a good idea. So what would be better more features but older sensor or new sensor but fewer features? (I know the 1300D has wifi capabilities. but I value that less than the movable screen. But I have never owned a DSLR so if wifi is crazy useful and I don't realize it please tell me.)


When are "because", "since","for" and "as" interchangeable?

I am not a native speaker. On a previous question of mine, I thanked for an answer by saying:     So the phrase is not an idiom, since it is applied in its literal sense.   I consciously chose since over because, because — well, I like that usage of since, even though I know that some (native speakers) don't like it. Nonetheless, that choice got me thinking for a while, and it occurred to me that I even could have used more alternatives, namely as or for, without changing the meaning.   So, on a general note, here are the alternatives:        Statement A (is true), because statement B (is true).   Statement A (is true), since statement B (is true).   Statement A (is true), as statement B (is true).   Statement A (is true), for statement B (is true).      Are these completely interchangeable? Or interchangeable in certain situations? Or can you point out any (not-so-)subtle differences between any of them? Are there even more synonyms?


For some reason my xp machine was using a user callcomp1, even though I had the main user set up as me. When I went into users it only showed one user.   So, to get rid of this is I ran Userpasswords2 deleted the Comp1 user then unchecked user must enter a name and password. It then promoted me for a password for the admin user.  I typed it in, noted it down. Reset the machine then got the login screen and  a password error.  I have tried everything from:  F8 SAFE mode- it does the same and asks for a password and won't let me in  Blank password - tried this  I've also tried Comp1 and my other user name, nothing worked.   Does anyone know how I can get back in my machine???  I don't have the xp disc and really don't want to lose my data. I have lots of pics of my kids on there that I can't bare to part with.


In this sentence:     Four items are responsible for three-fourths of the overall spending around the world, the most prominent share being that of food.   Why after the comma, the verb "being" is used? Why it does not use "is"?


How to properly duplicate image for "clone" form?

I have a form for cloning entries. Basically it works the same way as entry add form, it saves under brand new ID, but is pre-filled with data from existing entry.  For data like text and references, this is easy. Problem starts with images. I do not want to reference one image in multiple entries, it would not be convenient for reasons that are out of scope of this question. So I wrote simple function:  function _file_copy_by_id($fid) {   $source =  file_load($fid);   // Copy to the same place, let the Drupal care for renaming   $result = file_copy($source, $source->uri, FILE_EXISTS_RENAME);    return $result->fid; }   And in my form I made image field look like that:  'DimensionImageFile' => array(   '#type' => 'managed_file',   '#title' => t("Image"),   '#title_display' => 'invisible',   '#upload_validators' => array(     'file_validate_extensions' => array('gif png jpg jpeg'),     'file_validate_size' => array(variable_get('mymodule_image_size', 5 * 1024 * 1024)),   ),   '#upload_location' => 'public://mymodule/image',   '#theme' => 'preview_upload',   '#default_value' => _file_copy_by_id($product_data['DimensionImageFile']), ),   Now, it looks OK when form is rendered:    In the database, it looks OK too. Exported entry:  INSERT INTO `file_managed` (`fid`, `uid`, `filename`, `uri`, `filemime`, `filesize`, `status`, `timestamp`, `origname`) VALUES (426, 16, 'test.jpg', 'public://mymodule/image/test_3.jpg', 'image/jpeg', 37237, 1, 1391088561, 'test.jpg');   No entry in {file_usage} - just as expected.  File is there, with number added properly, but when I try to save, all I get is:     The file used in the Image field may not be referenced.     If I will add "fake" usage, like this:  function _file_copy_by_id($fid) {   $source =  file_load($fid);   // Copy to the same place, let the Drupal care for renaming   $result = file_copy($source, $source->uri, FILE_EXISTS_RENAME);   file_usage_add($result, 'mymodule', 'clone', 0, 1);   return $result->fid; }   form works all right. But files are reported as used. That's bad, because if user will decide to remove and replace them, cloned ones should get deleted as soon as possible, and the fact they are reported as being used prevents cleanup deletion.


Does the MacBook battery cycle count reset when replacing a battery

I've been  on battery cycle counts and checked out my current count on my MacBook (13-inch, Aluminum, Late 2008) - recommended maximum cycle count is 500.  I've had this laptop now for over 4 years and at the 2 year mark I had the battery replaced by AppleCare. The first time I checked out the cycle count was today and it's currently on 1004. Now my question is, is this the cycle count of the battery since I replaced it (as in, it reads the cycle count from the battery), or is it the combined cycle count (as in, it stores the count somewhere and increments occasionally)? My assumption is that it's the count of that battery but I have no idea how to verify this.  Either way, it looks like I need a new battery ;)


What TV show has kids entering a video game of some sort?

I've been searching the entire Internet for this show about 4 teenagers that enter a video game world where they have to fight monsters that looked like insects. Every time they had to enter the world, they'd go down in the sewers and one of the guys had a skateboard, a girl had a scooter and that's what I can remember. There was also one guy that always stayed behind to check their "health" in the game and pull them out in case they took too much damage to avoid them dying inside the game. I don't know if it was animated or not so there's not much to go on at all but hopefully someone might know what show it is?


I want to stop live time in java script. How can I do it. This is my live time java script source code.          setInterval(function(){         var d = new Date()         var h = d.getHours()         var m = d.getMinutes()         var s = d.getSeconds()         h = (h < 10) ? ("0" + h) : h;         m = (m < 10) ? ("0" + m) : m;         s = (s < 10) ? ("0" + s) : s;         document.getElementById("time").value = h +":"+m+":"+s }, 1000)   document.getElementById("time").setAttribute("disabled","disabled") document.getElementById("time").clearInterval(value)


May I use a question mark in the middle of a sentence? Examples:  Would you like the drapes to be white? or perhaps something off-white? Would you like the logo to be centered? at the bottom? left off entirely?


change the font of chapter title and section title

I am trying to change the font and format of heading using titlesec package. However it gives me the following error.    Missing { inserted \tableofcontents <br> Missing { inserted \chapter{Introduction}    The code:  \documentclass[10pt, letterpaper]{report} \usepackage{thesis}   \usepackage{titlesec} \renewcommand{\chaptername}{CHAPTER}{\Large} \titlespacing*{\chapter}{0pt}{0.5in}{0.3in} \titleformat{\chapter}[display]         {\normalfont\Large\centering\uppercase}{\chaptertitlename\ \thechapter}{0pt}{\Large} \titleformat{\section}{\large\bfseries}{\thesection}{1em}{}   \begin{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \tableofcontents  \chapter{Introduction}  Some text.  \end{document}


Intuition for the exponential of a matrix

I'm trying to understand an algorithm that tries to map points from a lie group to its lie algebra using the exponential map. The background is the representation of 3d coordinate transformations as a lie group.  I can imagine, how one can map points on a manifold (eg a sphere) to the tangent space (tangent plane) at some point x on the sphere. I can imagine to create the tangent space by computing derivatives at that point x. But I cannot imagine how the exponential of some matrix is giving me that tangent space?  How can I envision the exponential of a matrix? Is there some picture or analogy I can use as intuition?


I encountered a gconf2 error while installing some packages, what should I do?

I got this error when installing some software:  Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 5 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Setting up gconf2 (3.2.0-0ubuntu1) ... I/O warning : failed to load external entity "/usr/share/gconf/schemas/compiz-wobbly.schemas" Failed to open `/usr/share/gconf/schemas/compiz-wobbly.schemas': No such file or directory I/O warning : failed to load external entity "/usr/share/gconf/schemas/gwd.schemas" Failed to open `/usr/share/gconf/schemas/gwd.schemas': No such file or directory dpkg: error processing gconf2 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mutter-common:  mutter-common depends on gconf2 (>= 2.28.1-2); however:   Package gconf2 is not configured yet. dpkg: error processing mutter-common (--configure):  dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of libmutter0:  libmutter0 depends on mutter-common (>= 3.2); however:   Package mutter-common is not configured yet.  libmutter0 depends on mutter-common (<< 3.3); however:   Package mutter-common is not configured yet. dpkg: error processing libmutter0 (--configure):  dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of gir1.2-mutter-3.0:  gir1.2-mutter-3.0 depends on libmutter0 (>= 3.1.92); however:   Package libmutter0 is not configured yet. dpkg: error processing gir1.2-mutter-3.0 (--configure):  dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of gnome-shell:  gnome-shell depends on gir1.2-mutter-3.0; hNo apport report written because the error message indicates its a followup error from a previous failure.                                                                       No apport report written because the error message indicates its a followup error from a previous failure.                 No apport report written because MaxReports is reached already                                                                               No apport report written because MaxReports is reached already                                                             owever:   Package gir1.2-mutter-3.0 is not configured yet.  gnome-shell depends on libmutter0 (>= 3.2.1); however:   Package libmutter0 is not configured yet.  gnome-shell depends on gconf2 (>= 2.28.1-2); however:   Package gconf2 is not configured yet. dpkg: error processing gnome-shell (--configure):  dependency problems - leaving unconfigured Errors were encountered while processing:  gconf2  mutter-common  libmutter0  gir1.2-mutter-3.0  gnome-shell E: Sub-process /usr/bin/dpkg returned an error code (1)


I'm having some trouble with a question in my linear algebra textbook:     Let $A$ and $B$ be positive definite matrices, and let $Q$ be a unitary matrix.   Prove that if $A=BQ$, then $A=B$.   I tried to play around with the given equality, but I'm not getting any results. Tips would be appreciated:)


Looking for a book about alien insects invading earth

I remember reading a book back in the late 80s or early 90s about earth being invaded by aliens that looked a lot like insects.  I thought it was written by Gary Gygax but I can't figure out what they were called.  I think there were 3 books in the series.  The protagonist was a young man.   Sorry I can't remember any more than that.


Explaining the joy behind Math to the Common Folk

As a math student, it is hard for me to explain the beauty of math to non-mathematicians. So I wonder, how can one explain the elegance of abstract mathematics to somebody without a special background in math, but who is genuinely interested in understanding the joy that comes with it? To make this clear: I am not asking about how to present knowledge in an understandable way so that your friend actually knows what a manifold is for the rest of her/his life. It's more about giving a VERY general idea of why some crazy people (called mathematicians) would consider an induction proof elegant or even beautiful. This should be adressing adults who got through high school, so I suppose more advanced concepts than  or  are desirable. Something that might take an hour to explain but is worth the effort. What beautiful theorems or ideas do you know of that make sense intuitively to non-mathematicians when explained in the right way? Which of them are obviously beautiful, even if one doesn't know all the details about it?


How do I install ubuntu server from a usb stick?

How do I install ubuntu server system from a usb stick?


Why aren't my compile guards preventing multiple definition inclusions?

I have a header file  x.h which is included by more than one *.c source files. This header file has some structure variables defined.  I have put multiple inclusion prevention guard at the beginning of the header file as:  #ifndef X_H #define X_H ... .. //header file declarations and definitons.   #endif//X_H   On building I get linker errors related to multiple definitions. I understand the problem.   Won't a multiple inclusion prevention guard at the top of header file as I have, prevent multiple inclusions of the header file x.h and thereby avoid multiple definitions of the variables that are there in x.h? #pragma once does not work on this particular compiler, so what is the solution?  Someone had posted  answer to a similar question. It doesn't seem to work for me. How does this solution work?


Will a bullet fired from a gun perpendicular to the surface of Earth return?

How will a bullet having very high velocity and having little mass  behave when fired from the Earth perpendicular to the surface? It will be a great help if somwone explained it? Will it come back? Or will it escape into the outer space?


Sql injection, i am not sure if there is something more that i need to know

I saw a lot of websites in google on which i found vulnerability for SQL injection. Of course most of them were index.php?id=1 or something similar. Why is it that something tells me that even if i use prepared statement on such page, i will still be vulnerable for SQL injection? I mean... how can there be so many websites vulnerable for SQL injection. Is that link safe if i use prepared statements?? Seeing so many vulnerable sites using such link just blows my mind. I ask myself, there is no way people can be that stupid? How can they code so professional looking websites with vulnerabilities like this. I know how the prepared statements work. When you use prepared statements, you prevent the database to read the input as code. It's just the fact that i saw so many websites vulnerable for attacks.. it made me have heavy doubts in my mind about my website. I use exactly the same method for my users page, here is my code.    <?php // Setting the input ID to variable if(isset($_GET['id'])){ $the_input_id = $_GET['id']; }else{ header("location: ?page=error1"); exit; }  global $db; $stmt = $db->prepare("SELECT * FROM users WHERE id=:id"); $stmt->execute([':id' => $the_input_id]); $result = $stmt->fetchAll(); $db = null;  // Checking if there is result ... if (!$result){ // If there is no result ...     header("location: ?page=usernotfound");     exit; }else{ // If there is result ...     // Show the user profile }  ?>     This is the code from my users page, this is based on the user's input but as you can see i am using prepared statement. I am still worried about it. Maybe there is something more that i need to know about the security? I keep having heavy doubts in my mind after the sites i saw today.   I also saw some forums that are not using links like index.php?id=1. They use something like this "www.randomforum.com/index.php?/user/1029498/". Well, how does that work? That link cannot be SQL injected i think. I am not so experienced in this so i need someone to explain to me how does that kind of link work. I think that works the following way:  -Each time user gets registered, a new file get's created in the "user" folder. The file name is the ID of the account of the user. And that file just contains the user's page.  This is my explanation of how that forum works... but i am sure i am wrong. Please give me some opinions. Thank you for your time.


Mass search and replace (Not many files, many instances)

Im doing a project at university where i need to replace the names of people in a chat log we have.  The problem is, i have over 900 unique names i need to replace, and manually doing so would take a lot of time, time i do not have. I have the names extracted and a list of the replacement names, i just need a smart way of mass replacing them. Again, this is not replacing in many different files, its replacing many different things in the same document.  I've been working in Notepad++ trying to do this, but cant seem to find the answer.   Edit: I have looked earlier at the answer provided in  however as mentioned its 900 unique names, and creating a script described there would also be very time consuming. The person is asking for 2 instances of find and replace, i need over 900


I am playing fallout shelter and one of my women is pregnant. It has been a few hours now but she still has not given birth? i do not know what to do? I have tried to upgrade the room incase I did not have anough room that id not work. I do not know whether it is because she is radiated. I am just not sure.


How can I update  Adobe Flash Player. My YouTube video is not working.


As you know, when you ask your question on Stack Exchange you can, then and there, answer it yourself as well. I had a major issue with iframes in . I found the solution, and my boss wanted me to detail the problem and solution so other developers in our company could avoid it as well.  Well, I thought I'd do it through Stack Exchange and share my results with the wider web as well, but this happened:     I really expected no one to answer the question, but some one did and my answer was pushed down.   So I have two problems with this:   It took me three hours to write this, and I intended the question and answer to be read in sequence. In essence you can criticise this and say I wrote an article, but you try to come up with good question for something like this, especially when you already know the answer. This was the best I could think of. State the problem in the question & state the solution in the answer. But it's still intended to be read as a continuous text, more like an article than anything else. The second issue is, that the answer given by the other user is incorrect. I tested it, and now there is this incorrect answer between my question and correct answer that was intended to be read in sequence with the question.   So I would like to propose this.   When a Q&A style question is posted, the OPs will remain together unless another answer has more up votes. In fact, I would think it would be more correct for them to remain together permanently unless the OP answer receives down votes, but I do not think that would fly well on Stack Exchange. When a Q&A style question is posted, the OP's answer will be automatically accepted. When something like this is done, the OP already is the correct answer. It's possible that someone will give a better answer, but if that happens the accepted answer can simply be replaced not to mention it's highly unlikely for something like that to happen. I think this would make sense, because this would discourage (and yes I know, taboo) answering half ass answers like the one I got. When someone answers an already accepted question they always put more thought into it and basically keeps down noise. And yes, I am using the term noise here, because when the Q&A is posted it's usually with a good solution that works.


Proportionality constant in crater equations

I have searched for equations regarding craters and I came across two of them. The first one is from  in the level two section. There, it says that, $$ D^3\propto E $$  where $E$ is the kinetic energy. It is not really an equation as there is a constant of proportionality, $K$, there. That's when I came across a second equation from  that says, $$ D=0.07C_f\left(\frac{g_e}{g}\right)^{1/6}\left(E \frac{\rho_a}{\rho_t}\right)^{1/3.4} $$ where $\rho_a$ is the density of the impactor, $\rho_t$ that of the object, $g_e$ Earth's gravitational acceleration, $g$ the gravitational acceleration of the object, and $C_f$ the collapse factor. So these equations somehow contradict each other.  So I've been searching for the values making up $K$ using these two equations, but I'm wondering, is it possible to find $K$? Or do these equations not relate to each other at all?  I am writing my extended essay on this topic, so I did a 'drop the ball on sand' experiment. Can the more complex equation be used in this case? Also, I'm not sure what crater collapse factor means.


How to get a set $E$ such that $0<\mu(E\cap I)<\mu(E)$ for all interval $I$?

The solution of problem 6 (page 3)  uses a measurable set $E\subset\mathbb{R}$ such that $0<\mu(E\cap I)<\mu(E)$ for all interval $I\subset\mathbb{R}$. Could someone give me an example of a set that satisfies this condition?  ($\mu$ is the Lebesgue measure)  Thanks.


Calculating modulus varies the result with 0 at the beginning

I was implementing a code to calculate a modulus of a number.  Ex.   long n = 70464307456L; // input value int res = n % 256;  The result I got here was 0, which is expected.  The next input was 070464307467L (this input had leading 0) I was expecting to get the result as 11 for this input, but the result I got was 55.  But when removed the leading 0 from the input, the result was 11.  I did not understand this behavior when 0 is at the beginning.  Can someone please help me to understand?  Thanks in Advance.


assigning value to specific index leading to change in value at all indexes

Why on assigning value to a specific index in 2d array of python, changes all the index with the value?  def binomial_coff(n, k):     inter = [[-1]*(n+1)]*(n+1)     for i in range(n+1):         inter[i][0] = 1         inter[i][i] = 1     print(inter)     for i in range(2, n+1):         for j in range(1, i):             inter[i][j] = inter[i-1][j-1] + inter[i-1][j]             print(i, j, inter[i][j], inter[i-1][j-1], inter[i-1][j])     print(inter)     return inter[n][k]   I had tried the block in jupyter notebook and repl.it


In linear models we need to check if a relationship exists among the explanatory variables. If they correlate too much then there is collinearity (i.e., the variables partly explain each other). I am currently just looking at the pairwise correlation between each of the explanatory variables.  Question 1: What classifies as too much correlation? For example, is a Pearson correlation of 0.5 too much?  Question 2: Can we fully determine whether there is collinearity between two variables based on the correlation coefficient or does it depend on other factors?  Question 3: Does a graphical check of the scatterplot of the two variables add anything to what the correlation coefficient indicates?


Change the application icon theme but not changing the panel icons

Downloading and setting a new icon theme modifies the top panel icons. I want to keep the panel icons (Ubuntu-mono-dark theme).        Is that possible? How can I change the applications/folders & files icon theme (for example  Moka theme), but keeping the default top panel icons (Ubuntu-mono-dark)?   After setting Moka theme, the panel icons are changed, and I don't like them.


Given two open sets, show their sum is open

Show that if either $A$ and $B$ is open, then $A + B$ is open.   Attempt: Suppose $A$ is open, then for every $a \in A, $ there exists $\epsilon > 0$ such $B_{\epsilon}(a) \subset A$. Similarly suppose $B$ is open ,then for every $b \in B, $ there exists $\epsilon > 0$ such $B_{\epsilon}(b) \subset B$.  So $A + B$ is open since for every $a + b \in A + B$  there is $\epsilon > 0$ such that $B_{\epsilon}(a+ b) \subset A + B$.  Can someone please verify this is correct? Any better approach or feedback would really  help.


Is image seen in optical bench experiment using two pin and convex lens real or virtual?

Is the inverted image formed in optical bench experiment using two pins and convex lens real or virtual ?  how am i able to see it without screen if it is real ?  we clearly see an inverted image of needle, but it appears to come from behind the lens rather than from air where real image should form. so it must be virtual ?


How can I change the default screen resolution?

Here's the scoop: I have a crappy VisionQuest TV that I am currently using as a monitor on my computer running XBMCbuntu. It defaults to 1280x768 which the TV will not display correctly. It appears to be the correct size, but the screen is panned WAY to the left. The TV works fine on 1024x768 with the screen sitting in the right spot. Problem is, I have to change the resolution to 1024x768 every  time I boot up.   Any ideas?


How to secure POSTs made by limiting where they are sent from

Okay firstly I have a question that question being - Can people view what posts are being sent? For example, in a flash game when a POST is made to a web page, is there any way a user can view that POST's data?  If they can then my original idea of posting a password wouldn't work. But I didn't think a password would be that efficient anyway.  So.. what's the best way to make it so source A can only post to source B.  I hope you can understand what I'm trying to achieve here.


A finite group characteristically simple is isomorphic to a direct product of simple groups.   Does anyone know of a book that contains this proof? I just need to reference it, but in the books I've been looking for, I have not found.


I found the following subgroups: $H_1=\{I_2,A_\pi\}$ $, H_2=\{I_2,F_v\}$ $H_3=\{I_2\ ,F_h\}$ $H_4=\{I_2\}$ $H_5=\{I_2,A_\pi\,F_v,F_h\}$  Is my answer correct? Are there more subgroups?


Why are my if-else statements not printing what they're supposed to?

I am doing a school coding project, in which (using Dr. Java) I code a game of rock, paper, scissors. My game asks the user for their throw, while randomly generating the computer's throw.  The code below represents my (incomplete) method for determining the winner of the game. It’s supposed to first check if the two throws are the same, then, if they are not, compare the two throws to see who won. The final else-statement is a backup, in case the user inputs an answer other that rock, paper, or scissors.   Currently, the string compAnswer is hardcoded to "rock".        if (userAnswer == compAnswer) {     System.out.println("Huh. A tie. That was... disappointing.");   win = 2; } else if (compAnswer == "rock"){  { if (userAnswer == "paper") {     System.out.println("Curses! I threw rock and lost!");     win = 0;   } else if (userAnswer == "scissors") {     System.out.println("Hah! I threw rock and crushed your scissors!");     win = 1;   }} } else {   System.out.println("...You cheater! That's not a legal throw! Off to the fire and brimstone with you!"); }    However, when I run my program, nothing gets printed- not when userAnswer gets "paper" or "scissors", or even when the answer is bogus. I’m at a loss here- why are my print statements not being triggered?


I tried following  to customize time and date in gnome panel for 18.04.  But I cannot find clock override in Package Manager.


I had booked a ticket for travel through Indian Railways using IRCTC and got a confirmed ticket. While booking, I mentioned the details of a four year old child who will also be traveling.but it does not get mentioned in ticket anywhere.   Will it create any problem while boarding the train?


This was one of my shower thoughts: what if someone from the party engages in combat out of a whim?  Example:  There is a 4 player party (classes does't matter right now) against a wizard and his guard. For the opportunity of battle, it is stated that players and the wizard are enemies. While some players are for a diplomatic solution between the wizard and the party, one of the players decides to come up to the opposing guard and stab him.  Should they roll initiative in this moment, or after the first stab? I don't think that the wizard and his guard should be surprised by this attack.


How to disable auto power off of usb devices like usb mouse?

I don't know how , but somehow automatic power-off of usb devices got accidentally enabled. Now my usb mouse goes off even if it's idle for 2-3 seconds. It's really irritating.  This happened after I installed powertop and powernap. Maybe it has something to do with these two applications.  How can I disable this "feature"?


i am trying to make Java ucanaccess program and for some reasons i am not able to insert record to database and have appeared some error messages as following:  package lcp_v1;  import java.awt.BorderLayout; import java.awt.EventQueue; import javax.swing.JButton; import java.awt.event.ActionListener; import java.awt.event.ActionEvent; import java.sql.*;  public class DB2 extends JFrame implements ActionListener {      private JPanel contentPane;     private JTextField id_tt;     private JTextField name_tt;      Connection con;     Statement st;      /**      * Launch the application.      */     public static void main(String[] args) {          EventQueue.invokeLater(new Runnable() {             public void run() {                 try {                      DB2 frame = new DB2();                     frame.setVisible(true);                 } catch (Exception e) {                     e.printStackTrace();                 }             }         });     }      /**      * Create the frame.      */     public DB2() {         try {             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);             setBounds(100, 100, 577, 550);             contentPane = new JPanel();             contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));             setContentPane(contentPane);             contentPane.setLayout(null);              JLabel lblEmployeeId = new JLabel("employee id");             lblEmployeeId.setBounds(39, 53, 123, 23);             contentPane.add(lblEmployeeId);              id_tt = new JTextField("");             id_tt.setBounds(161, 50, 136, 29);             contentPane.add(id_tt);             id_tt.setColumns(10);              JLabel lblName = new JLabel("Name");             lblName.setBounds(39, 118, 71, 23);             contentPane.add(lblName);              name_tt = new JTextField("");             name_tt.setColumns(10);             name_tt.setBounds(161, 115, 136, 29);             contentPane.add(name_tt);              JButton insert = new JButton("Insert");             insert.setBounds(39, 388, 105, 30);             contentPane.add(insert);             insert.addActionListener(this);              Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");             String dataSource = "jdbc:ucanaccess://D:/Database.accdb";             con = DriverManager.getConnection(dataSource, "", "");             Statement st = con.createStatement();          } catch (Exception e) {         }     }//end DB2 constructor            public void actionPerformed(ActionEvent ae) {          try {              String id = id_tt.getText();             String name = name_tt.getText();             String s1 = "INSERT INTO Table1 (ID, Name) VALUES (id,name)";             st.executeUpdate(s1);             id_tt.setText("");             name_tt.setText("");          } catch (SQLException e1) {             e1.printStackTrace();         }      } }                                                   please tell me what error did i make.thanks a lot


I had applied for UK visa recently and it got refused

(refused latter UK embasy)  The decision :  i have refused your application for a visit visa because I am not satisfied that you meet the requirements of paragraph 4.2 of appendix V : immigration rules for visitors because:   you stated that you wish to visit the UK for 6 days as a tourist. under the UK immigration rules you must show that you are qualify for a visa by explaining your own circumstances and the plans you have for visit.it is your responsibility to satisfy me that they are such that if guaranteed leave to enter you will abide by all of the conditions attached to any such leave and that you will leave the United Kingdom on completion of proposed visit. You state that you are unemployed. You have stated that you are traveling withe your spouse and that he is funding your visit.you have not stated that how you are supported.you have provided property documents withe your application but this documents do not dimostrareate that you drive an income from them.i also note that when your spouse received his uk visa last October he stated that he had an online business. The documents you have provided do no demonstrate this business or that you or your spouse receive and income such a business. The documents you have provided do not demonstrate how you support your self in bangladesh and as such I am not satisfied that they are an accurate reflection of your financial circumstances in bangladesh On the evidence available to me today, I am not satisfied that your circumstances are as stated in your application. Therefore I am not satisfied that you are a genuine visitor to the UK for a purpose that is permitted by the visitors rules or that you intend to leave the uk at the end of your proposed trip (appendix V: 4.2 a c   I am going to reapply. What was wrong with my previous application? What do I need to provide in addition to other documents so as to ensure that I get the visa? What was wrong with my earlier application and what corrective steps should I take for my next application?   thanks in advance  Farhana Rumpa


I have an error when using pst-func package

when i use pspicture* to draw a chart this error occurs but plotted. file:framed.sty  error:no room for a new \dimen.


I changed my username and now I cannot play online

I don't understand this and I'm now worried as I have donated to a lot of servers and I don't want to lose this account. On the launcher it says my new username but when I log on it says "Account not Authenticated with minecraft.net" and "Non-Valid Username".  How can I regain the ability to use my account online?


What is the difference between "photo" and "image"?

What is the difference between photo and image?


Is it possible to get the URL of the external system from which a user has modified a record in Salesforce?

I'd like to know if is it possible to get the URL of an external system from which a user has modified a record. For example, if a user gets connected to  (or SalesLoft, or another one) and updates a given record, how can I get "workbench.developerforce.com" (to be stored in a field)?


Need help identifying this 'space novel'

I remembered reading a novel that has the following plot points:   The protagonist is a human male coming from a planet that provides mercenary services he is the sole survivor of the planet the rest of the planet died because of radiation poisoning from imported grain(?) sent by some evil faction(?) because the mercenaries are detrimental to their plan he was 'abducted' by a group of people known as the overseers(?) his bone -- damaged by radiation -- is replaced with an unbreakable stuff he has a companion, a female from another galaxy, whose appearance is not humanoid but more like a bat(?) he can 'talk' with her through telepathy   Plot points I'm not really sure about, I've marked with a (?).  I think I read the novel (borrowed from a long-defunct library) sometime in the late '80s or early '90s.  If anyone can give any hints/clues as to what that novel was, I'd be very grateful...


Using * works great when I'm just searching for a word, but often I want to search for a phrase or a filename that appears in code, and it would be nice to just visually select the string and be able to hit * or # to search for it. This turns out to be more complicated than I hoped. I started with this:  vnoremap * y/\<<c-r>"<cr>\>   But this breaks if my string has a forward slash in it. I tried getting it to automatically replace forward slashes with the \/ combo, as follows:  vnoremap * yo<esc>pV:s-/-\\/-ge<cr>0D"_dd/\<<c-r>"<cr>\> " y                - yank the text " o<esc>           - open a new line " p                - paste the string " V:s-/-\\/-ge<cr> - replace / with \/ " 0D"_dd           - Grab the string and get rid of the line I just created " /\<<c-r>"<cr>\>  - Do the search   The there are (at least) two problems with this: It won't work if I can't edit the current file, and it blows up if I'm trying to grab text in a comment. When I use o on a commented line, the new line starts with a comment which means it won't scoop up the right text when I run 0D. Is there a way to make this work the way I want?


understanding bias correction in ADAM algorithm

why is possible to approximate E[gi^2] with E[gt^2]? by the time we go to the t timestamp, we've already made weight updates, which mean gradients should be different as they are taken from different points in parameter space?  I guess we get error term(zeta) by making same approximation but are we really getting rid of that by doing the so-called bias correction, I don't think so


The character is the R in this picture:    I was thinking mathcal or fraktur, but it doesn't seem to be either of them. I tried the Detexify tool and What The Font, but couldn't find anything suitable.


There is a series which most people will be very familiar with.  $$S=1-1+1-1+1-1+\cdots$$  We all know that it is divergent hence $S=\lim\limits_{n\to\infty}S_n=\lim\limits_{n\to\infty}\sum\limits_{i=0}^{n}(-1)^n$ has no limit value.  But on the other hand there is a method to make $S$ has a value. Looks like that: $$\begin{equation}S+S=(1-1+1-1+\cdots)+1-1+1-1+\cdots\\ =1+(1-1)+(1-1)+(1-1)+(1-1)+\cdots\\=1\end{equation}$$  Now we have $S=\frac{1}{2}$.    I am wondering that Does the result imply that a divergent series can also have an exact sum? Does the sum of the alternative series contradict the divergence?


mac terminal displaying other name than host name

I have recently been in terminal and somehow I lost my Mac name.  It's showing a strange IP followed by some numbers.  My computer's name is "my-xxx-macbook-pro."  When I type hostname I receive:  ip-10-xx-xx-xxx.us-west-2.compute.internal  I have been working in AWS a lot to try to develop some products.   How do I get back to my computer in terminal?


Show that if $\sum x_n y_n$ converges for all $y=\{y_n: n\}$ in $\ell_2$ , then $x=\{x_n :n\}$ is in $\ell_2$.  I am not able to go anywhere with this problem. Please help


Why does less friction in a wheel result in more speed?

Everyone knows that racing bikes have narrower wheels and that, by definition, friction reduces speed. What I don't understand is that since at no time is the wheel of the bike in horizontal motion relative to the road, surely any friction between the wheel and the road will have no negative effect and in fact aid the forward propulsion of the bike as a whole?


Latex distributions. What are their main differences?

What are the main differences among:    TeX Live  teTeX  fpTeX MiKTeX proTeXt MacTeX gwTeX OzTeX AmigaTeX PasTeX


Heap versus Stack allocation implications (.NET)

From an 1 about Heap and Stack, it raised me a question: Why it is important to know where the variables are allocated?  At  someone pointed that the stack is faster. Is this the only implication? Could someone give a code example where a simple allocation location change could solve a problem (eg. performance)?  Note that this question is .NET specific  1 the question is removed from SO.


I've been wondering whether in Harry Potter canon there is any hint on whether there is energy expenditure involved in doing magic. Hints would be things like increased tiredness, fatigue after doing several spells, the need to eat more, etc.


If MSE rep is used for voting, why is it tied to privileges?

I realize I am taking a risk by reopening what seems to be an old, hoary, and thorny discussion. However, it seems that in all the long discussions about Meta Stack Exchange reputation, what it means, and why it's separate from reputation on other sites, I have never seen a complete answer to this question:  If reputation on Meta Stack Exchange is used by the community to indicate agreement with an opinion instead of the quality of a post, why is it still tied to site privileges?  The association between reputation and privileges makes sense on other Stack Exchange sites, where reputation is a measure of your participation in the site and the quality of your questions and answers. If you contribute positively to the community your reward is increased privileges, whereas your punishment for "polluting" the site with bad questions or unhelpful answers is a loss of privileges.  However, on Meta Stack Exchange, reputation is a measure of the popularity, not the quality, of your contributions. Tying reputation to privileges means that losing privileges on the site is a punishment for expressing an unpopular opinion, and gaining them is a reward for agreeing with the majority.   My opinion:  I don't think that tying privileges to popularity makes sense as a feedback system. It doesn't really encourage quality contributions, and even worse, acts to suppress minority opinions through the threat of losing privileges. As a user with fairly low reputation, I am afraid of asking a question that may be controversial, because if enough other members disagree with me I will be stripped of the ability to vote and chat. Even if I had higher reputation, I would still be concerned that expressing a controversial opinion would cause me to lose helpful privileges like editing and viewing close votes.   The FAQ tells new users "not to be concerned" by downvotes because all it means is that the community disagrees with them. However, I think new users have every right to be concerned about downvotes, because they still mean the loss of privileges.


I recently was under interview conditions (white boarding) and was asked to detail a task that still has me thinking about it now.  The premise was simple - and no doubt hardly novel.     //main    for (int i = 1; i < 6; i++)    {         Thread t = new Thread(() => ThreadWork.MemberMethod(i));         t.Start();                 }     static class ThreadWork    {         public static void MemberMethod(int i)         {             Console.WriteLine(i);         }    }   A pretty standard question about thread synchronicity - why is the output variable and not 1-2-3-4-5 every time? I gave a rough answer about creating a callback structure using delegates so that each previous threads execution had concluded before firing the next. Truth be told, I didn't field the question too well.  My answer was somewhat along these lines -  delegate void Del(int i);  //main Del handler = ThreadWork1.MemberMethod; for (int i = 1; i < 6; i++) {        Thread t = new Thread(() => handler(i));        t.Start(); }  static class ThreadWork1 {     public static void MemberMethod(int i)     {         Console.WriteLine(i);     } }   Running it now, I can see that this method does not work, at least in its current iteration.  I found an example from a blog that suggested using locks, a quick modification later and I had this:  //main ThreadWork2 threadwork = new ThreadWork2(); for (int i = 1; i < 6; i++) {     Thread t = new Thread(() => threadwork.MemberMethod(i));     t.Start(); }  class ThreadWork2 {     public void MemberMethod(int i)     {         lock (this)         {             Console.WriteLine(i);         }     } }   Yielded similar result - variance in output.  Am I close with any of these attempts? Or should I consider an entirely different approach.


scope/yscale not transforming coordinates?

To my understanding of the documentation, the scope block should transform all coordinates. However, in the following example, only circles themselves are scaled, but not their centers: black circles are without yscale, red ones are with yscale=.5, and are centered at the same points (a), (b):    What is the problem? Am I misunderstanding the docs?  \documentclass{minimal} \usepackage{tikz} \begin{document}     \tikz{         \coordinate (a) at (0,0);         \coordinate (b) at (0,1);         \draw (a) circle (.5);         \draw (b) circle (.5);         \begin{scope}[red,yscale=.5]             \draw (a) circle (.5);             \draw (b) circle (.5);         \end{scope}     } \end{document}


Superscript in upper left to denote isotope in LaTeX

I am trying to denote a 28Si isotope. I used  $^{28}Si$. In the output, the chemical symbol is in italics, also there is an unnecessary space between the symbol and the nucleon number.  How do I get the chemical symbol 'Si' in roman, and the superscript and symbol a bit closer? I will use this code to denote a label in a Python code graph.


Capitalising a sentence whose first word is explicitly lowercase

Possible Duplicate:          Let's say that you have a word that should be typed with leading lowercase letter. Perhaps it's a computer command. Perhaps it's an Internet nickname. I can't find any more serious examples.  When you put that word at the beginning of a sentence, should you capitalise it?     cat allows you to display contents   of a file.   The convention is that commands are typed in fixed-width font, so this doesn't stand out as much.     soccer_boy_89 turned out to be my   sister's account.   This does, though.  Of course you could paraphrase the sentence such that the problematic word is not the first one, but that's not the point here.


Why are "malign" and "malignant" pronounced differently?

Why are malign and malignant pronounced differently?  What is the rule that separates that pattern from, say, sign and signage?


Assume that a continuous function $f:]1, 2[ \rightarrow \mathbb{R}$ satisfies the conditions      $$x\to1⁺ = -\infty \text{ and } x\to2^- = -\infty$$      Show that there exists and $c \in ]1, 2[$, for which every $x \in ]1, 2[$ holds $f(x) \leq f(c)$   This is essentially a special case of the Weierstrass theorem (Extreme Value Theorem) where they don't give us the actual function. How do we find the closed interval so that we can show the existense of $f(c)$?


How to find the build / version of Windows 10

During the beta of Windows 10 it was hard know what version you were running unless it had it posted to the desktop. Once that wasn't there - how do you tell what version / build you are running?   This will become more of an issue as Microsoft starts releasing more builds with the new update mechanism.


How to partition an existing non-partitioned table

I have an existing table with data:  dbo.Test (col1,col2,col3....) ON [PRIMARY]   I need to change this table to be partitioned like this:  dbo.Test(col1,col2,col3....) ON Ps_Date(Col2)   How I can I achieve this without dropping and recreating the table?


Explain the difference between these two SQL Queries?

First Query:  SELECT      d.id,     d.brand_name,     count(*) AS no_of_time_used FROM content oc LEFT JOIN drama d ON d.id = oc.drama_id LEFT JOIN orders o ON o.id = oc.order_id     AND o.fundraiser_id IS NOT NULL GROUP BY drama_id ORDER BY no_of_time_used DESC;   Second Query:  SELECT      d.id,     d.brand_name,     count(*) AS no_of_time_used FROM content oc LEFT JOIN drama d ON d.id = oc.drama_id LEFT JOIN orders o ON o.id = oc.order_id WHERE o.fundraiser_id IS NOT NULL GROUP BY drama_id ORDER BY no_of_time_used DESC;   There is only one difference in these queries that's AND vs WHERE. In First Query, I have used AND just after the second JOIN Statement whereas in the second query I have used WHERE in place of AND.  Edit:  Both Queries are returning different result.


How do we know that the universe is really fine-tuned?

How physicists come to the conclusion that the cosmological constant and the other constants are really fine-tuned in a way that if they are changed just a bit, then stars and life won't exist?


List all sections in TOC in one line wrapped

How can I list all sections under a chapter in TOC, in one (wrapped) line (without pagenumber is fine)? Thanks.  Expected,:  Chapter 1 .................................................... 10  section 1 -- section 2 -- section3 -- section 4 - secti-  on5 -- section6 -- section 7  Chapter 2 .....................................................15  section 1 -- section 2 -- section3 -- section 4 - secti-  on5 -- section6


How to get random value from array, but give better chance to higher values

I was wondering if there is a function, or how to write a clever one that can make the task. Let's imagine array like this: $arr = array(25, 35, 40);  I'd like to get key of random value from this table, but I'd like to have 25% for $arr[0], 35% for $arr[1], and 40% for arr[2] - depending on the values. There might be any number of values in array, and the sum is not always 100(%) - this is just example. I figured out such solution: $arr = array(123, 1856, 84, 84, 2, 654, 321);//just an example $temp = 0; $rand = mt_rand(1, array_sum($arr)); foreach ($arr as $key => $value) {     $temp += $value;     if ($temp >= $rand)     {         $random_key = $key;         break;     } } echo 'key of "random" element is '.$random_key;  Can it be done better?


Difference between $var === 1 and $var === TRUE in PHP

While reviewing a pull request, I noticed my colleague is using a lot of truthy checks in the following manner:  if ($var === 1)   This doesn't work as expected for one condition in particular:   if(!empty($myArr) === 1) {  } //   I know this won't work as expected in javascript, upon consulting , I am not 100% sure if this would work properly in PHP either.  My question is, would this work OK in PHP? Which one is a better way of checking for comparisons?  true or 1  Using php 7.2


What determines the pronunciation of the prefix 'arch-'?

In the case of an archbishop, or archvillian it is pronounced arch.  In the case of archetype, it is prounounced ark-e-type  In the case of an archenemy I think you would say ark - enemy  Is it simply the fact of a vowel following the arch that turns it from arch to ark?


cd to a path containing spaces using a path variable

I have a file containing a list of commands which I run from my .bash_profile as   source my_cmds   For eg:  $cat my_cmds  scripts=~/scripts   assuming my $HOME is /Users/knayak, when I run cd $scripts in the prompt, it takes me to /Users/knayak/scripts  Now, I have a path in this form(which cannot be renamed for some reasons), for which I don't know how to set a command variable so that I can cd $path using that variable.  /Users/knayak/Somedir - some name Inc/Tasks   I tried adding all these in my my_cmds file to set an environment variable tasks,    $cat my_cmds  tasks=~/Somedir - some name Inc/Tasks tasks="~/Somedir - some name Inc/Tasks" tasks=~/"Somedir - some name Inc/Tasks" ...   and many more, including single quotes in some, but none of them seem to work when I do cd $tasks. Most of them fail with the error.     cd: "/Users/knayak/Somedir: No such file or directory   I need to set the proper value in the form tasks=~/<whatever>  for cd $tasks to work with this path?


I want to show (or rather, know why) $$\sum_{k = 1}^{\infty} \frac{k^2}{k!} = 2e.$$ I have tried using the power series expansion for $e^x$, and also series manipulations with $\ln(x)$, but with no success. Any hints would be appreciated.


Distribution of range of Uniform $(0,1)$ distribution

Let $X_1,...,X_n$ be iid as $U \sim [0,1]$ with pdf $f(x) = 1(0 <x< 1)$. Determine the range distribution.   I have managed to determine the distribution of the minimum and the maximum, however I cannot/do not know how to determine the distribution of range.   Minimum:  $f_N = n(1-x)^{n-1}$ and maximum $f_M= nx^{n-1}$   I am aware that the calculation of range distribution is based on convolution: $f_R=\int f_{N,M}(x,x-r)dx$, However I cannot get the correct result, which according to my lecture slides is : $f_R= n(n-1)r^{n-2}(1-r)$  Could someone break this down for me ? My math background is not great


"Xterm" or "xterm" in configuration file

After starting to use Arch I switched to xterm and urxvt terminal and enjoyed the flexibility of them (esp. scaleHeight resource). However, I don't understand why sometimes configs work with Xterm and sometimes with xterm or XTerm (lower vs upper case x and t).  For example, I have this odd config that is working on Ubuntu:  XTerm*faceName: terminus XTerm*faceSize: 11 XTerm*saveLines: 16384 XTerm*loginShell: true XTerm*charClass: 33:48,35:48,37:48,43:48,45-47:48,64:48,95:48,126:48 XTerm*termName: xterm-color XTerm*eightBitInput: false xterm*VT100.geometry: 100x80    ! <------ this line would not work with "Xterm" or "XTerm" XTerm*scaleHeight: 1.3          ! <----- but all others work with "XTerm"   However, my Arch box runs on "xterm" fine. The same is true for URxvt terminal: I can't simply port my Arch .Xresources to Ubuntu14 work box because parts of it stop working, and I get different setups after running:  xrdb -merge .Xresources   X.org on xterm did not have any examples (searching for "xterm*" did not return anything on that page). I see examples with Xterm, xterm and XTerm online... It baffles me that the config above works since it is syntactically off. Why is this the case? Does it maybe have something to do with new or old resources in X? Thanks!  xterm on ubuntu is Xterm(297). I don't have access to my Arch box at the moment, but it would be pretty up-to-date. I don't know how to tell Xterm version from Arch's repos, but maybe this:  So, if that link is right, then yes, I am running different Xterm versions.  I tried upgrading xterm, but it is still 297.  apt-get update && apt-get install --only-upgrade xterm   I can't do it now, but I might try to recompile the latest version to see if the issue is there.  Following the suggestions by ILMostro_7 below I tried XTerm.vt100.geometry, which still did not work. This is Xterm (297) on Ubuntu14. So basically, . or * it seems to only work with little xt.    Result of appres XTerm xterm | grep geometry thanks to Gilles. I did not think to look up what exactly xrdb -merge does which resulted in this mess. So my guess is that one of these takes precedence over everything else?  xterm.VT100.geometry:   100x100 xterm*VT100.geometry:   100x80 xterm*VT100*geometry:   50x50 xterm.vt100.geometry:   160x40 xterm*vt100.geometry:   100x20 xterm.geometry: 5x5 xterm*geometry: 100x20 XTerm.VT100.geometry:   100x100 XTerm*VT100.geometry:   50x50 XTerm*VT100*geometry:   20x10 XTerm.vt100.geometry:   100x5 XTerm*vt100.geometry:   40x40 XTerm*geometry: 50x50   In fact it looks like xterm.vt100.geometry:   160x40 takes precedence over other ones since that the instance I keep getting. Also, I somehow managed to completely screw up Xterm menues (Ctrl+mouse click) - they show up as a small yellow line. Hehe


I am looking for an elegant way to run unit tests on multiple data, in this case a directory containing text files .  Consider a folder text containing several txt files, I want run this example unittest on each file ( for example by feeding a list of files from glob to my unittest )  Here is how I test a single hardcoded file .  import unittest import parser  class TestParser(unittest.TestCase):     text_path = 'text/journal.txt'      def test_get_chapters(self):         x = parser.get_chapters(self.text_path)         self.assertGreater(len(x),1))  if __name__ = "__main__":     unittest.main()    Thanks !!


Which muggles are allowed to learn about magic?

Other than the obvious first-degree family members, it is also indicated that the Prime Minister of the United Kingdom knows about the wizarding world.  Who else can be revealed to magic? Who's the one to decide (some specific entity in the ministry)?  Only one example, where the rules are blury, is asked already  if a wizard or a witch were dating a muggle, how soon would it be ok for them to share their secret? Do they have to wait until they are married first?


"I have been there first time": Does this sentence sound awkward?

I have been there first time.   The reason why I think this might not be natural is that the expression "first time" seems to describe "past". You do not use the present perfect with an adverb indicating "past", in my understanding.  However, I feel the phrase below is not that funny.     This is the first time that I have been there.   I am wondering about the relationship between "the first time" and "I have been there". "That" could behave like a relative adverb. If that is the case, the antecedent of "that"—"the first time"—is shared with the following clause: "I have been there". Then, is it OK to say "I have been there first time"?  By the way, Google searches for "" and " in the UK domain show just 33 hits for the first phrase and 10 hits for the second.


Word or phrase for "using excessive amount of technology to solve a low-tech task"

If you look at  of a drone replacing a lightbulb, you'll understand what concept I'm trying to find a word for. Using dynamite for fishing would be another example.    I'm looking for a word that describes the use of high-tech equipment, for a purpose that is normally filled by low-tech equipment, usually done out of laziness or amusement.  This is specifically relating to technology (overengineering is very close).


As I've seen online, there are problems with this stage in the game for so many people. I've looked up some solutions to fix the mission but they don't seem to work for me at all.  I've tried clearing everything and then re-placing it all but that doesn't work, it still hasn't checked off anything I've built despite everything being built, present and ready to go.  When I try storing parts to then try replacing them again the game won't let me chose the store option, so I'm stuck with all the parts that the game has registered as not there. I'm absolutely stuck. I have no clue how to correct this so I can move on with the story.   I have all the right components. 1x Molecular Beam Emitter, 2x Relay Dish, 1x Stabilised Reflector Platform- placed directly underneath the Beam Emitter, 1x Control Console and have them all on the same circuit connected to the correct amount of power for each component to function.  EDIT:  I'm playing on a PS4 and I went with TBOS, I'm building it in the airport. I've also removed all objects, such as seats and carpets, from the area. My problem is that the game is not acknowledging each piece of the machine I'm building and when I try to remove any of the machine items it doesn't allow me to so my only other option is to build duplicates of each component, which doesn't do anything to progress the mission.


I can't access to the login screen in Lubuntu 16.04 LTS

I have a Toshiba NB300 with 1 GB RAM with Intel® Atom™ processor N450 and I recently installed Lubuntu 16.04 LTS i386 and I have this message on the screen instead of the login box  /dev/sda6: clean, 124768/2379216 files, 881581/9509376 blocks   How can I fix it?


Using Ubuntu via a USB on low spec machine

With 2GB RAM & 1.3Ghz processor, is using Ubuntu via USB practicable?


Difference between cheap and expensive HDMI cables in terms of performance?

I happened to wander around John Lewis's electronics sections yesterday (for the uninitiated it's a chain of upmarket department stores in the UK) and I came across an , 1 metre long that retailed for 59.99 pounds (or about 94 dollars). Only recently I bought a 2 metre-long HDMI cable for 2.99 (or about 4.70 dollars) that I have been perfectly happy with.  Is there any practical difference? I mean the price difference is just staggering, what more could I possibly get by shelling out for such an expensive HDMI cable apart from possibly better coating and that swivel adapter? Are these cables really faster and in what respect?


Update to 10.15 Catalina even though Big Sur is released

I'm still on 10.14. I would like to work with Xcode 12 now, which only supports 10.15+. Yet, no direct download for 10.15 can be found anymore. I do not want to make the move to macOS 11 Big Sur yet as it seems too unstable.


How do I determine the likelihood of a single measurement coming from a known distribution?

I have a set of 2000 numbers that form an approximately normal distribution, with a mean of about 0.24, and an SD of 0.06.  These form an estimate of the population.  I now have a single sample measurement of 0.38 and would like to determine the chance (p value) that this single sample measurement comes from the same population distribution.  (Unfortunately, in my work the nature of the "test" means that it is unfortunately theoretically impossible to obtain another measurement).    It must be true that the further that the single sample is from the mean of the population, the more unlikely that single event is.  Furthermore, of course one needs to take into account the distribution of the population - had the SD of the population been 6 rather than 0.6 the chance of obtaining the single measurement at 0.38 would be much higher, and hence the p value lower.  I am happy to assume for my purposes that the distribution from which the sample has been obtained would have the same SD as the population.  The question is how I calculate the likelihood (p-value) that the observed single sample comes from a distribution with the same mean as the population?  I have thought about carrying out a one sample t-test, testing whether the observed population is different from the single sample value, but that doesn't seem right to me as that test assumes that the single sample value is the mean of the distribution being tested against, rather than a single sample.  What is the best approach to this analysis?  Thanks in advance for any advice and help.


NullPointerException when i use @Secured in my RestController

I am a beginner in Spring Security, so I coded a controller with two methods like this :  @RestController public class EtudiantRestService {      @Autowired     private EtudiantReository etudiantReository;      @Secured(value = {"ROLE_ADMIN","ROLE_SCOLARITE"})     @RequestMapping(value = "/saveEtudiant",method = RequestMethod.GET)     private Etudiant saveEtudiant(Etudiant etudiant){         System.out.println(etudiant.getNom());         System.out.println(etudiant.getPrenom());         return etudiantReository.save(etudiant);     }      @Secured(value = {"ROLE_ADMIN","ROLE_SCOLARITE","ROLE_PROF","ROLE_ETUDIANT"})     @RequestMapping(value = "/etudiants")     public Page<Etudiant> listEtudiant(int page,int size){         return etudiantReository.findAll(new PageRequest(page,size));     } }   The configurations of spring security is :  @Configuration @EnableWebSecurity @EnableGlobalMethodSecurity(securedEnabled = true) public class SecurityConfig extends WebSecurityConfigurerAdapter {      @Autowired     public void globalConfig(AuthenticationManagerBuilder auth) throws Exception{         // Type d'authentification (Base de données, LDAP, Mémoire)         auth.inMemoryAuthentication()                 .withUser("admin").password("123456")                 .roles("ADMIN","PROF");         auth.inMemoryAuthentication()                 .withUser("prof").password("123456")                 .roles("PROF");         auth.inMemoryAuthentication()                 .withUser("etudiant1").password("123456")                 .roles("ETUDIANT");         auth.inMemoryAuthentication()                 .withUser("scolaritel").password("123456")                 .roles("SCOLARITE");     }      @Override     protected void configure(HttpSecurity http) throws Exception {         // Pattern builder         http             .csrf().disable()             .authorizeRequests()                 .anyRequest()                     .authenticated()                         .and()             .formLogin()                 .loginPage("/login")                 .permitAll()             .defaultSuccessUrl("/index.html")             .failureUrl("/error.html");     } }   Mon contrôleur fonctionne bien mais lorsque j'utilise la annotation @Secured et j'authentifier j'avais l'exception :  java.lang.NullPointerException: null     at com.upsys.sec.service.EtudiantRestService.saveEtudiant(EtudiantRestService.java:29) ~[classes/:na]     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_102]     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_102]     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_102]     at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_102]     at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]     at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]     at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]     at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapt     ....


this is my first time writing here. I am starting to use RDKit but I found the installation very difficult. I have Ubuntu 20.04 LTS and python3 (anaconda). Following the procedures posted at de oficial website of  I first try to install rdkit from repositories by: $ sudo apt-get install python-rdkit librdkit1 rdkit-data  But it goes with errors because python-rdkit is not found:  Unable to locate package python-rdkit  So I try: sudo apt-get python3-rdkit this have installed python3-rdkit but then when I want to use it, it doesn't work. Besides, it is not found among the packages when I check using conda list. What is the correct sentence for importing python3-rdkit? Is it the same as rdkit? Then, I decided to install rdkit as an env following the installation with conda recommendations. It works but it creates an env with python2.7 and pandastools doesn't work properly. Besides, the rdkit version installed is 2017 when the last release is 2020. How can I get installed the latest version of rdkit and using python3 with pandastools working? I will appreciate any help! Again I have found rdkit dificult to install for a non-programer user. Thanks in advance!


How can I insert a newline in a framebox?

I have several frameboxes in my document, using the following command:  \framebox(115,115){ R-Sq: \newline For example}    I want to force a new line, but neither \newline or \\ appear to work. Is there any other way of doing this?


Terrible undergraduate transcripts. Everything else is good. Is it still worth applying to a Ph.D program in economics in a top 30 U.S. university?

I am an international student who is thinking of applying to a Ph.D program in economics at some top 30 economics departments in the U.S. I have a bachelor's and a master's degree in economics. My GRE, both verbal and quant, puts me well above the 90th percentile. My TOEFL is very high. I have three outstanding recommendations, probably placing me at the top of my master's class and comparing me favorably with former coleagues that were accepted to top universities. My master's disertation will make for a very good writing sample (the paper that grew out of it is serious research, publishable in the best theory journals) and I have two years' work experience at a prestigious job at the public sector. My master's transcripts are almost impeccable, even though I completed a LOT more coursework than what was required to graduate. I have plenty of maths coursework under my belt.  The only "small" wrinkle is: I was the archetype of a wayward student as an undergrad. My undergraduate transcripts are a disaster, as in I flunked 12 of the 70 courses that I enrolled in, simply because I had the terrible habit of abandoning classes when there was something more interesting going on. What I want to know is if this problem destroys my chances of acceptance.


I don't have a lot of knowledge of special relativity and associated topics; some of the few things I know are that "all motion is relative" (that is, there is no 'stationary reference frame'), and the speed of light in vacuum ($c \simeq 3 \cdot 10^8~\mathrm{m~s^{-1}}$) is the absolute asymptotic speed limit (asymptotic meaning that you can never equal it, only get arbitrarily close). What escapes me is how those concepts work together - to my naive understanding, an object would never move in its own reference frame (and so would never reach $c$). What reference frame is $c$ measured against? (Is it measured against a reference frame?) Or am I looking at this the wrong way?


Prove that there is no group $G$ s.t. $\operatorname{Aut}(G)=\mathbb{Q}$  I get the feeling that we should proceed by contradiction.   So let $G$ be a group s.t. $\operatorname{Aut}(G)=\mathbb{Q}$. Then we can identify elements of $\mathbb{Q}$ with automorphisms of $G$... and identities such as $\frac{1}{2}*2(g)=1(g)=g$  Can somebody help me find a contradiction?


Comma after "Unfortunately" in the beginning of a sentence.

Here, Cambridge doesn't use a comma.  I am confused. Example in Cambridge Dictionary: Unfortunately we can't come this evening after all.    On different pages i found some rules telling there needs to be a comma. Examples follow:  We do usually put a comma after adverbs like 'unfortunately'. They are called 'sentence adverbs' because they modify the whole sentence and often give the opinion of the speaker/writer.  A parenthetical phrase adding detail to the main clause. Initially placed parentheticals are normally set off by a comma.  Cause I'm studying for my Level 2 graduation, i want going crazy reading here and there comma rules followed by looking in the Cambridge Dictionary without finding them there.   HELP me out please !


Identifying Windows 10 \Device\Harddisk1\DR2

I'm getting errors in Windows 10's event log stating \Device\Harddisk1\DR2 drive controller is having a problem. I know that the hard disk numbers depend on the BIOS and do not match the physical connections.  How can I tell which physical device this actually is? diskpart lists these devices:    Disk ###  Status         Size     Free     Dyn  Gpt   --------  -------------  -------  -------  ---  ---   Disk 0    Online          931 GB      0 B        *   Disk 1    Online         1863 GB   927 GB   Is \Device\Harddisk1 the "Disk 1" listed here? Is there some other way to determine what Windows 10 means by Harddisk1 ?  What is DR2?


How to stop "permission denied" app toasts after denying permissions?

I often like to deny app permissions that I think the app does not need but yet they keep requesting for the permissions even after Denying, resulting in lot of toasts [package name] has been denied [permission name] permission.  How do I permanently suppress these toasts?  I am using android Kitkat.