CUPS asking for login creds to set up a printer

I am trying to set up an HP .   In the CUPS web interface, I have tried entering root user & pw as well as my user/pw and neither seems to work.  I am able to print, though hplip does not show the printer as a detected device and just sends me to CUPS interface to add...kind of circular and getting nowhere.  I am running Ubuntu (18.04.3).  I already had current hplip print mgr, but it won't show the printer; keeps sending me to CUPS to set it up.


I'm trying to show a form on clicking #createbook followed by submitting the form via AJAX. For test purpose, I am trying to alert hello world on clicking #addme but its not working.But when I entered the on click function on the browser and it works. Can you guys help me figure this out. Thank you. :)  <div id="mode" style="display:none">  </div>  <script>     $("#createbook").click(function () {         $.get("BooksLibrary/Create #create", function (data) {             $("#mode").html(data + '<button class="btn btn-primary" id="addme">Add Book</button>');         });         $("#mode").dialog({             modal: true,             title:'Add Book'         });         $("#mode").css({ "display": "block" });     });       $("#addme").click(function () {         alert("hello world");     }); </script>


Identical strings comparison gives me false

I have two identical strings, one in an array and one in a String variable. When I compare these IDENTICAL strings I get false every time. I have debugged and debugged, but I get the same result every time. Here is the code in question  String temp = ""+(num1*num2); Boolean equal = temp == answers[i];  if(equal) {     correct[i] = true;     num_correct ++; }else{     correct[i] = false; }   Again, I have debugged every minor detail of this program and I am 101% sure that the strings are IDENTICAL. Why is Java returning false on comparison?


I spent a good hour today moseying after some azure-winged magpies. We had a nice waltz across a parkland, they rarely letting me get close enough to even contemplate a shot. As such, I spent long stretches (~10min) with my Nikon DSLR on but not in use.  And then I began wondering about power drain in such situations (switched on but untouched), and how different that status actually was from off, and after what period of time it makes sense to go ahead and switch the camera off?


Why should I believe that matter does not expand along with the space between it

This question has been asked before under other guises. I am not a scientific profesional however i have some schooling in pyhsics and mathematics and have a keen interest in these subjects.  It seems plausible to me and was a thought i had my self many years ago whilst at college, that the universe could possibly be expanding from within itself. Ie matter and space were expanding at the same rate as each other.  I observe there is no relative distance increase between the objects i see on a day today basis and as such this type of expansion wouldn't change our perception of this relatively speaking. Everything we observe would remain the same and we would be unaware of the expansion..


Here is a puzzle challenge for you: Suppose $X,Y$ are independent and identically distributed Random Variables. Show that $$P\{|X-Y|\le2\}\le 3P\{|X-Y|\le 1\}$$


Shell Syntax: How to correctly use \ to break lines?

I used to believe that  the appropriate way of breaking the lines in a list is  command1 && \ command2   It turned out that it isn't so , one doesn't need \  $ [  $(id -u) -eq 1000  ] &&                                                    > echo yes yes   The same works with pipes | the same way.  The bash man page sections on pipelining and lists didn't shed any light on this.  Thus , my question is : what is the proper usage of \ to break long lines ?


Need help understanding an electronic oscillator (Schmitt trigger + capacitor)

When we use this circuit, the LED blinks. I know an inverter transforms high to low voltage and low to high voltage, but here the voltage source is connected to the inverter all the time so the inverter receives high voltage all the time, right? Then why does the inverter ever have a high output?  Also, what's the role of the capacitor in all of this? Here I have the same question as before: it's connected to the voltage source all the time, so when does it ever discharge?  I'm trying to understand this circuit picturing the electron flow as that is currently the only way of understanding it with my limited background knowledge.


Issue with rendering fire on Transparency

I am having an issue with rendering fire on a transparent background. I've gone into the world and changed the alpha from the sky to transparency. I've checked the transparent box under the render properties, under the film section. However, when I do this only my emitter renders, not my fire simulation. Unchecking the box under the film section causes renders to return to normal. Any help would be appreciated. Wondering if something is setup incorrectly with my nodes? Or If I am missing some setting.  Thanks!


Proof of odd number of divisors of a perfect square

How do we prove that a perfect square has an odd number of divisors? Eg 1024 is a perfect square and it has $11$ divisors comprising of  $2^0$,$2^1$,$2^2$,...$2^10$


Number of points on elliptic curves over finite fields

I noticed that for elliptic curves of the form $y^2≡x^3+a\pmod p$ sometimes the number of points is always $p+1$ for any choice of $a$. This seems to be the case for all $p ≡ 5 \pmod 6$. Moreover, when this does not happen, i.e., for $p ≡ 1 \pmod 6$, it looks like there are exactly zero curves of such form where the number of points is $p+1$. Can someone point me towards the right direction as to why this happens?


As per my understanding in C#, when an object is assigned to another object of same type, its reference is copied instead of the value. So I would like to know how to assign an object to another object such that its values are copied and not referenced to the second object..


Looking for name of sci-fi short story: all non-human life on earth eliminated to preserve equilibrium

I'm hoping someone can help me as this is driving me nuts! Context and Chronological info I'm trying to find the title/author of a short story that I read in some or other anthology ages ago. I couldn't give you an exact date but I'd say it was probably 50s/60s. Plot The human population has increased to the point where input and output of resources on Earth is in exact equilibrium. As such, no other living matter can be permitted to exist, as its use of resources would throw this equilibrium out of balance. One man in a vast tower block has managed to hide some flowers, and, I think, one or a few small animals - perhaps a mouse. These are detected by the relevant authorities, and the story ends when an official arrives at the apartment and requires the man to destroy them - the last non-human living things on Earth.


While trying to follow , I encountered the following error while attempting what seems like a simple sudo edit operation:  $  sudo gedit /var/lib/dpkg/status  ** (gedit:14898): WARNING **: Command line `dbus-launch --autolaunch=0bd873023a78bdb34ca1b9650000000b --binary-syntax --close-stderr' exited with non-zero exit status 1: Autolaunch error: X11 initialization failed.\n Cannot open display:  Run 'gedit --help' to see a full list of available command line options.   Running the same without sudo correctly launches gedit, but of course without editing ability. Does anyone have any idea what is going on?


$W_{t}$ is a Wiener process. I mean, it seems that it is a Markov process, though I don't see an easy way to prove it. Because, I mean, I don't see how it can be proved that it is a Markov process using definition or the fact that for Markov processes $P(X_{s}|X_{t_{n}}, ... , X_{t_{1}}) = P(X_{s}|X_{t_{n}})$. Any thoughts?


How to count packets coming from outside using iptables?

If you don't give iptables a target, it simply counts how many bytes and packets match the rule. I'd like to count all packets that come from outside, i.e. don't match 10.0.0.0/8 and don't match 192.168.0.0/16.  My first intuition is:  iptables -A INPUT ! -s 10.0.0.0/8,192.168.0.0/16   However this adds two rules, of which each count separately, and no count of outside packets is discernible. So how do I count outside packets?


Why was this question deleted over code allegedly copyrighted by Embarcadero?

The following question was closed:    I, and others, voted to re-open the question. I also flagged the question saying:     This question was closed incorrectly by a single moderator vote. Can we get it open again please?   This flag was marked helpful but then the question was deleted by the moderator . Lasse also left the following comment:     This question, and answer, contains code copyrighted by Embarcadero. Not only will it stay closed in its current form, it will also be deleted.   I don't believe, although I could very well be wrong, that either question or answer contains code copyrighted by Embarcadero. As a licensed user of Delphi Profession, I have the source code to the Delphi libraries which is where I presume Lasse believes the source code originates. I cannot find it there.  I flagged the question again saying:     I don't believe that there is copyright violation here. Could the supposed violation be made more clear?   This flag was  with the comment:     A moderator reviewed your flag, but found no evidence to support it.   Clearly one of the moderators, presumably Lasse believes that this code violates Embarcadero copyright. I would like to see the evidence for that assertion. I fully understand that I may be mistaken and that this really is a violation of Embarcadero copyright and that I simply have not found or do not have access to the copyrighted code in question.  For what it is worth, the question was later re-posted: .


Why does this object initialization work?

I do a classical JavaScript object initialization like this, it works like a charm:  function Hero(a, n) {                                                                 this.nom = a;                                                                     this.job = n;                                                                     this.quiSuisJe = function() {         return "Mon nom est "+this.nom+" et je suis un "+this.job;     }  }                                                                                var x = new Hero("Joe", "Ninja");                                                 var y = new Hero("Jinx", "Carry AD");                                             console.log(x.quiSuisJe());                                                       console.log(y.quiSuisJe());    But if I change the quiSuisJe function like this:  function Hero(a, n) {                                                                 this.nom = a;                                                                     this.job = n;                                                                     this.quiSuisJe = function() {         return "Mon nom est "+a+" et je suis un "+n;     }  }                                                                                var x = new Hero("Joe", "Ninja");                                                 var y = new Hero("Jinx", "Carry AD");                                             console.log(x.quiSuisJe());                                                       console.log(y.quiSuisJe());    It works. Why?


Bash can't run command from script: mkdir command not found

I have separate scripts for tasks in bash. Here is the broken one:  #!/bin/bash PATH=/home/name/ mkdir $PATH cd $PATH && echo "done." exit 0   Today it broke and first time it simply didn't want to run cd, but created directory. Second time it just said "mkdir command not found." Running this commands exactly with semicolon works fine. What the case?


I want user foo to auto-login using LightDM (which has been used by Ubuntu since version 11.10). How would I do that?


Performing deep learning land cover classification using R?

I am really new to Deep Learning and, unfortunately, I can't find example codes on land cover classification other than  where the author wrote a script in R for a large dataset.   The main reason that I am asking is because recently I found a few papers on Remote Sensing Image classification using Deep Learning and I was wondering if there were any R examples on that subject.  So, is there a code example, preferably a step-by-step, which I can use?  I found several git repos like  that can do Deep Learning classification with R, BUTT, I am still looking for a simple multi-spectral image segmentation method. An example of that can be found at  and I also found a similar question in  for which the answer is "use something else other than R if you can".  If I find anything that works today I will be posting a working answer.


$\lim_{x\to 0} \frac{\sin x - x}{x^2}$ without L'Hospital or Taylor

It is easy to see that $$\lim_{x\to 0} \frac{\sin x - x}{x^2} =0, $$but I can't figure out for the life of me how to argue without using L'Hospital or Taylor. Any ideas?


If Obi-Wan and Yoda were trying to keep Luke safe from Vader, why would they let him keep the Skywalker name?

Obi-Wan and Yoda didn't really make a good effort at hiding him, especially considering they let Vader's family adopt him.


pgfplots and log scale: bars starting from the bottom of the screen

The following MWE  \documentclass{standalone} \usepackage{tikz} \usepackage{pgfplots} \begin{document} \begin{tikzpicture} \begin{axis}[ybar,ymode = log] \addplot coordinates{ (1,1e-15) (2,1e-14) (3,1e-13) }; \end{axis} \end{tikzpicture} \end{document}   compiles to this bar chart:    I'd like the bars to start from the bottom of the screen instead of the top, since it makes more sense to visualize my data like that (they are computational errors).  Is there a pgfplots option to achieve that? The manual only says that the bars always start from 0 (and there is no way to change that); clearly, when ymode=log this is interpreted as starting from log(1)=0, which is not what I want here.


Greater value for year rep than total rep

I was looking at the rep leagues for Interpersonal skills from last year, when I noticed something odd. There are several users on the list whose total reputation is listed as being less than their reputation for the year. It's usually a small amount (less than 50). This makes me think that it's likely that the year rep doesn't take into account rep losses from down voting answers and posting bounties.  However, I came across one where the difference is quite substantial (~1400).    When I checked the user's profile, I saw that they posted 100 rep worth of bounties and voted less than 30 times, so that wouldn't explain a gap this large. What exactly is going on here?


Command to print few consecutive lines from middle of a file

For a file containing 20 lines, lines 6-10 can be printed using following command:  head -10 filename | tail -5   Can this exactly same thing be done without using 'head' and 'tail' commands ??  Please comment the link if similar question already exists.


How to prove $\limsup_{n\to \infty} \sqrt[n]{|a_n|}=\limsup_{n\to \infty} \sqrt[n]{|a_{n+1}-a_n|}$ if $\{a_n\}$ diverges

$\{a_n\}$ is a diverging sequence. I have proven that $\limsup_{n\to \infty} \sqrt[n]{|a_{n+1}-a_n|}\geq1$ by contrapositive.  Then, we need to prove $\limsup_{n\to \infty} \sqrt[n]{|a_n|}=\limsup_{n\to \infty} \sqrt[n]{|a_{n+1}-a_n|}$.  The hint says I can show $\leq$ and $\geq$ separately. But I don't know how to prove the inequality since $\{a_n\}$ diverges and has few properties. Can anyone give me some hints?


I wanted to copy a file using cp, however, I happened to type rm and the file was deleted.  How can I recover it?  The file is stored in a mobile hard disk drive with FAT32 file system  I'm using Mac OS X  Hoping someone can help me!


Is it possible to generate an electronic schematic automatically, and are there any tools to do this?

I was wondering if it is possible to automatically generate a schematic from some higher-level description (CPU ==> RAM, etc) of a circuit? And whether there are tools that can do that?


Sort Posts Alphabetically by Multiple Categories

Basically I have an array of posts which I want to sort by title.  $categories = get_categories('child_of=4');  $arr_records = array(); $post_data = array();  foreach($categories as $category)  {     $sub_catname = $category->cat_name;     foreach(get_posts('cat='.$category->term_id) as $post)      {         $arr_records[] = $post_id;         $post_data[] = $post;     } }  foreach($post_data as $show_post) {      echo $show_post; }   How do I sort the $post_data array?


Should I use log transformation for my linear regression?

I am modeling commissions earned based on non sales data. My equation looks like this:  commissions = Number of times logged into the system + ...    (many binary variables for HR related info)  Realistically, there would be a peak login, or plateau where any more logins is not correlated to commissions. So should I take the natural log of this variable?


How do I change the location where system restore points are saved?

How can I change the location (drive, path, etc.) where system restore points are saved on Windows 7?


In a grid, how to display long column headers

When displaying data in a grid (each row contains a record, each column a different record field), vertical space need is easily solved with scrolling or paging.  We are usually sooner missing horizontal space as the number of columns or column data becomes large. This topic is already discussed here:  and this is not the point of my question.  Some columns have data that occupy a little space (a check box, a date or an icon), but their header label is long. The result is that the column becomes wide because of the header, not the data, with an obvious loss of horizontal space.  There are some simple solutions:   find shorter header texts wrap the header text into multiple lines display the header text vertically display an abbreviation with a mouse over tooltip containing the complete label use an icon as a header   There are cases when none of these solutions can be applied, keeping a clear and easy to understand UI at the same time. What are your solutions?


If $n,m \in \mathbb{N}$ then there are $c,d$ such that $cd = (m,n)$, $(c,d) = 1$ and $(m/c,n/d) = 1$.

Suppose that $m,n \in \mathbb{N}$. Using the fundamental theorem of arithmetic it is easy to show that there exist $c,d \in \mathbb{N}$ such that $(c,d) = 1$, $cd = (m,n)$ and $(\frac{m}{c},\frac{n}{d}) = 1$.   Is there any quick way to prove this without using the prime factorizations of $m$ and $n$, i.e. only the basic properties of the gcd, lcm, etc.?


What is the correct substitute for rc.local in systemd instead of re-creating rc.local

I cannot find the correct way to execute some local scripts (or very local commands) at systemd, I already know I must not create a service (in systemd a unit) for this kinds of scripts (or I must?)....    The workaround that I found is to create rc.local and give to it execution permissions.  printf '#!/bin/bash \n\nexit 0' >/etc/rc.local  chmod +x /etc/rc.local   For example, if I get a legacy server with a simple rc.local configured by you, I will know what did you do and how much it gonna hurt to upgrade or install something new on the distro, as rc.local was respected by external packages, but in the other hand if I install a server and create a systemd unit or two or three (or even sysvinit services), just for doing a simple task, this can sometimes make your life harder, and much more than this my units names can someday conflicts with the names of the new services created by the distribution development, and maybe installed on a upgrade, causing trouble for my scripts !   I see another question asking about where is rc.local and the answer was to create it and give execution permissions, I think my question is really not a duplicate, because I do not want to know where it is - believe me, I just want to accept that it is deprecated, but i cannot find the correct way for doing this kind of things, should I really create a unit just for some simple like that?


Using Rank-Nullity Theorem, find dimension and basis for the Subspace $W$ of $\mathbb{Q}_{4} [x]$ consisting of all the polynomials $a_{0}+a_1x+a_2x^2+a_3x^3+a_4x^4$ such that  $a_1+a_2+a_3+a_4=0$.  Not sure how to use the theorem with this problem and very unsure what steps need to be taken.  Thank you in advance for the help.


My website returns 0 results for link:www.example.com why it not showing any results ? Is it because of all backlinks are low quality or what ? but In Google webmastertools "Links to Your Site" section it shows the link count. Please suggest me why it not returning any results. And I set my preferred domain to www.example.com


$f: \mathbb{R}^2-\{0\} \rightarrow \mathbb{R}$ is continuously differentiable and $f(\alpha x) = \alpha^2f(x)$, then $x \cdot \nabla f(x) = 2 f(x)$

Assume that $f: \mathbb{R}^2-\{0\} \rightarrow \mathbb{R}$ is continuously differentiable and $f(\alpha x) = \alpha^2f(x)$ for all $x\neq 0$ and $\alpha > 0$. Then I want to prove that $x \cdot \nabla f(x) = 2 f(x)$ when $x$ is nonzero.  I applied Mean value theorem in several variables and tried some linearity tricks but I could not prove it.


The sentence I want to write is something along the lines of: "I believe that the people here are what makes this such a great place to work".  I know people is generally plural and should be followed by "are," but for some reason it sounds off to me here. I'm curious if people in this context is more appropriately describing a singular population / entity and should be followed by "is" instead?


i’m trying to track when British Airways flight BA 2158 from Grenada West Indies landed at Gatwick Airport. The flight was scheduled to depart on 30th December 2017 at 18:20, but departed on 31st December 2017 around 00:30. It flew straight to London Gatwick direct, not stopping at Saint Lucia. It landed at London Gatwick on the 31st December, but am unsure of the time. Many thanks.


How to login into a sandbox from Sandboxes page in Production org?

We are able to login as a system administrator into the production org of one of our client. The client has sent his own credentials which he used to login. Now we are planning to use the Dev sandbox which is already available in the prod org.   The issue is when we click the login link it opens the login page and prompt me to enter password. the username is already populated suffixed with the sandbox name. i entered the same password which i used it for the prod org but not able to login got incorrect username or password. What would be the issue?   Please note the sandbox which already exists in the client prod org was created by someone else.   Do i need to refresh the sandbox in order to login with the current user credentials which i am using in production org?


Show other users' votes in suggested edit review

This is part 1 of a two-part suggestion. Part 2 is . Many borderline or bad suggested edits are still getting approved. At the moment, there is no good way to educate users who make bad reviews*. Reviewers and editors are never notified if their decisions are disputed, or when an approved edit gets rolled back. As one step to help that, the previous decisions of other reviewers, including custom reject messages, should be shown right next to the edit being reviewed.  This would help reviewers get an idea what other users think. It would also incentivize writing a custom reject message because there's a chance somebody will actually read it. The argument can be made that this would influence reviewers unduly; that every review is supposed to stand on its own without any external input. However, the benefit of showing the other decisions outweighs the negatives:  Some clueless reviewers will think twice if they see reject votes from experienced users.  seeing a lot of approve votes on a bad edit may aggravate inspire an experienced user to write a rejection message, helping educate new users.   also, it's not like Stack Overflow doesn't create plenty of bias when it comes to moderation decisions already - by showing downvotes and closevotes, for example. This might be an easy change with great educational value. * - One can post a comment underneath some SO contribution of the user to get their attention, but that is borderline stalking and should be used only in extreme cases. I also understand the team is firmly against any sort of punishment system for disagreeable reviews (like downvoting or flagging).


Personal Hotspot not working over Wi-Fi on iOS 13

After upgrade to iOS 13 from 12.4, I noticed that personal hotspot isn't working anymore over Wi-Fi (via USB is ok).  Tested on two computers with Win7. The PC can connect to Wi-Fi, but no valid IP (IPv4) is assigned and no connection is working to internet.


I need to determine (at least approximately) a motherboard model.   shows the following info:  System Manufacturer: AOPEN_ System Model: AWRDACPI System Type: X86-based PC Processor: x86 Family 6 Model 11 Stepping 1 GenuineIntel ~1300 MHz BIOS Version/Date: Award Software International, Inc. 6.00 PG, 17.12.2001 SMBIOS Version: 2.2   Sadly, my friend can't , because they have no administrator rights.  Is there a way to determine at least approximately the model of motherboard?  My goals are:   To determine the maximum supported memory size (to analyze possibility and rationality of upgrade) To determine processor requirements (socket etc to analyze possibility and rationality of upgrade)


LaTeX template for resume/curriculum vitae

If you have a TeX'ed resume, did you use a template or make your own? Are there any useful packages? What looks the most professional? How about special considerations for different areas of work (e.g. in academia)?


How do you get Pikachu as a starting Pokemon?

I heard it is possible to get Pikachu as a starting pokemon in Pokemon Go. How do you do this?


Preconfigured Ubuntu install iso / Custom installation routine

Is it possible to take the Ubuntu server iso and modify, so that you can create a custom installation routine?  The idea behind this is, that I'm going to deploy Ubuntu on a number of similiar PCs at work. They all need the same configuration, except for some variables, like network interfaces, etc. I don't really want to run the setup on 50+ PCs and then afterwards run around and make all changes over and over again.  So, is it possible to alter the installation routine of the Ubuntu iso? Thing I would like to be able to do:   Add new input fields, like "IP address" Add/Remove default packages change config files


Meeting like-minded people for forming collaborative research relationships

I'm quite new at doing full-time research as a career. It seems that everyone in my department whom I talk with is focused not only on "their" research but also on various side projects with other researchers — Including people who are newer than I am. What am I not doing which they are? — I don't want to simply go to everyone I meet and ask "what exactly are you doing, and do you need help with it?" (it sounds rather artificial/forced/desperate/etc.).  This is related to , but if I don't even know whom to approach, then the answers to that question are not very useful.


I updated my iPhone 4S to iOS 9, but now "0:00" appears sometimes in the text message window. Am I doing something to cause that to appear?


Permutations on the set of natural numbers.

I was in a course of Abstract Algebra, and the teacher asked some interesting questions at the end of a course on the material we had seen. I found the answer to the first question, but the other two leave me perplexed. Could you give me your opinion on the answers (2) and (3)?  (1) Is the function $f : \mathbb{N} \to \mathbb{N} $ such that $$f= \begin{pmatrix} 1 & 2 & 3 & 4 & ...\\ f(1) & f(2) & f(3) & f(4) & ... \end{pmatrix} = \begin{pmatrix} 1 & 2 & 3 & 4 & ...\\ 2 & 3 & 4 & 5 & ... \end{pmatrix}$$ is a permutation?  (2) Is there a function $ f \in S_E$ with $E = \mathbb{N}$  that is factorisable into disjoint cycle of infinite order such that $\mid \{n \in \mathbb{N} : f(n) \not= n\}\mid < \infty$ ?  Definitions :    $S_E$ is the set of all permutation of $E$.  Let the set $E \not= \emptyset$. We say that a map $f : E \to E$ has an inverse function, if there is a mapping $g : E \to E$ such that both composition $f \circ g$ and $g \circ f$ are the application identity for each $x \in E$. We say that $f$ is a permutation (bijection) of $E$ .    (3) Does the subset of functions $\in S_{\mathbb{N}}$ ($S_E$ with $E=\mathbb{N}$) consistent with $\{n \in \mathbb{N} : f(n) \not= n\}$ (the permutations that move only finitely many numbers) form a group?  Answers  (1) No, because $1$ isn't an element in the image.  (2) $$ \underbrace{\cdots \mapsto 6 \mapsto 4 \mapsto 2}_\text{even} \mapsto \underbrace{1 \mapsto 3\mapsto 5\mapsto \cdots}_\text{odd} $$ $$ n\mapsto \begin{cases} n-2 & \text{if $n$ is even and $n\ne 2$}, \\ 1 & \text{if }n=2, \\ n+2 & \text{if $n$ is odd.} \end{cases} $$ (3) If $f$ and $g$ move only finitely many numbers, then so does $f\circ g$.  Consider the intersection of the set of all fixed points of $f$ and the set of all fixed points of $g$.  That is the set of all numbers fixed by both $f$ and $g$.  Only finitely many numbers are not among these because the intersection of the complements of two finite sets is the complement of the union of the two finite sets, and the union of two finite sets is finite.  If $f$ moves only finitely many numbers, then so does $f^{-1}$.  Can we prove this last statement?  Then can we see that the two assertions here are all you need?


Prove $\sum_{i=0}^n {{n \choose i} \times 2^i} = 3^n $

I have to prove that $$\sum_{i=0}^n {{n \choose i} \times 2^i} = 3^n $$  Such that ${n \choose i} = \frac{n!}{i!(n-i)!} $ and $n $ is some arbitrary int  I proved we can expand 2^I in a way such that $$2^i = {i \choose 0} +{i \choose 1} + ... + {i \choose i} $$ But this doesn't seem to approach the proof is want so I tried to expand out ${n \choose i}$ and again this got ugly and led no where. I can't quite seem to find any approach that would lead to $3$ of any power.  I know this proof is true for the base case$$\sum_{i=0}^0 {{0 \choose i} \times 2^i} = 1 => {0 \choose 0} \times 2^0 = 1 => 1 = 1 $$ Could anyone give me a hint to lead me in the right direction?  EDIT: Wow, I always feel so stupid when I miss tiny identities such as that! Thank you everyone! I got my answer, I wish I could give all of you checks for the advice.


Software to check grammatical errors in Latex text

Is there any software, like Grammarly, that enables one to check the grammar in the text while using latex. The problem with using Grammarly is that with formulas and mathematical notation, it becomes very tedious to use Grammarly.


Trigger after insert calling method in class

Added a trigger which in turn calls a method in class but is failing. My error is:     Apex trigger MyTrigger caused an unexpected exception, contact your administrator: MyTrigger: execution of AfterInsert caused by: System.QueryException: unexpected token: 'TJ000000dsWeuMAE': ()   My trigger code:  trigger MyTrigger on Task (after delete, after insert, after undelete,  after update) {      MyClass c = new MyClass();      for (Task t : System.Trigger.new) {         if (Trigger.isUpdate)         {             c.UpdateTask(t);         }         else if (Trigger.isDelete)         {             c.DeleteTask(t);         }         else         {             c.AddTask(t);         }     } }   My class code:  global with sharing class MyClass {      Interaction_Summary__c intSum;      private string query;     private string filterClause;     private string filterClause1;     private string filterClause2;      global MyClass()     {                if(!Test.isRunningTest())         {             filterClause1 = MyCustomSetting__c.getValues('MyProperty').Filter_Clause_1__c;             if (filterClause1 != null && filterClause1 != '')             {                 filterClause2 = MyCustomSetting__c.getValues('MyProperty').Filter_Clause_2__c;             }             else             {                 filterClause1 = '';                 filterClause2 = '';             }         }     }      global void AddTask(Task t)     {            if (t != null)         {             intSum = new Interaction_Summary__c();             PopulateInteractionSummary(intSum, t);             if (filterPass(t))             {                 Schema.SObjectField upsertField = Interaction_Summary__c.Related_To_Id__c;                 Database.upsert(t, upsertField, false);             }             else             {                 DeleteTask(t);             }         }     }      global void UpdateTask(Task t)     {         //add code     }      global void DeleteTask(Task t)     {         //add code     }      global boolean FilterPass(Task t)     {            string taskID = t.Id;         filterClause = filterClause1 + ' ' + filterClause2;         if(filterClause != null || filterClause != '')         {             query = 'Select Id from Task where id = ' + taskID + ' '  +  filterClause;         }         else         {             query = 'Select Id from Task where id = ' + taskID;         }         Task thisTask = Database.query(query);         if (thisTask != null)         {             return true;         }         return false;     }      global void PopulateInteractionSummary(Interaction_Summary__c intSum, Task t)     {         intSum.Related_To_Id__c = t.Id;         intSum.IS_Subject__c = t.Subject;         intSum.Type__c = 'Task';         intSum.Related_To_Name__c = t.What.Name;     } }   Please help this salesforce newbie pinpoint the issue. Thanks in advance


Beamer with Berlin theme: slide in "hidden" section appears in navigation bar

I am trying to achieve the same thing as in  but using the Berlin theme, namely, I want to have a "Conclusion" slide at the end that does not appear in the top navigation panel.  By putting it in an empty-titled section as per the accepted answer I have succeeded in making it not appear as an additional slide in the last section. However, when the "Conclusion" slide is displayed, the navigation button to the first slide of the last section is highlighted (but the name of the section isn't). I would like to stop it, so that nothing in the top panel is highlighted when the "Conclusion" slide is displayed.  \documentclass{beamer}  \usetheme{Berlin}  \begin{document}      \begin{frame}         \titlepage     \end{frame}      \begin{frame}{Introduction}     \end{frame}      \begin{frame}{Outline}         \tableofcontents[pausesections]     \end{frame}      \section{Context}     \begin{frame}{Context}     \end{frame}      \section{Development}     \begin{frame}{Development}     \end{frame}      \section{Results}     \begin{frame}{Results}     \end{frame}     \begin{frame}{More results}     \end{frame}      \section{}     \begin{frame}{Conclusion}     \end{frame}  \end{document}


How to copy the filename quickly in windows

Want to copy the file name quickly in Windows. I always use rename, copy , but feel it is quite slow. Any better way?


Custom Validation using Trigger throwing System.FinalException: SObject row does not allow errors

I am trying to addError on the opportunities based on one condition. But getting System.FinalException: SObject row does not allow errors error while saving the record. Below I have given the code snippet. Please let me know how I can resolve the issue.  if(Trigger.isUpdate && Trigger.isBefore){         map<Id,Opportunity> newOpptyMap = (map<Id,Opportunity>)trigger.newMap;         OpportunityTriggerHelper.checkforStageDuration(newOpptyMap,Trigger.OldMap);     }   The function is below where I am adding the error statement  public static void checkforStageDuration(Map<Id,Opportunity> oldMap, Map<Id,Opportunity> newMap){         Map<Id,Opportunity> recordsToCheck = new Map<Id,Opportunity>();         for(Id oppId : newMap.keyset()){             if(newMap.get(oppId).StageName != oldMap.get(oppId).StageName){                 recordsToCheck.put(oppId,newMap.get(oppId));             }         }         List<Opportunity_Stage_History__c> oppStageHistory = [select Id,Expected_Stage_Duration__c,Opportunity__c,Duration__c,Reason_For_Delay__c from Opportunity_Stage_History__c where Opportunity__c IN :recordsToCheck.keyset()];         for(Opportunity_Stage_History__c oppHistory : oppStageHistory){             if(oppHistory.Duration__c>oppHistory.Expected_Stage_Duration__c && oppHistory.Reason_For_Delay__c==null){                 newMap.get(oppHistory.Opportunity__c).addError('The Opportunity has crossed it\'s Stage Duration, Please fill the Reason for Delay !!');             }         }     }


I have a Samsung Core i3 laptop. When I wanted to change my Windows I could not find the CD-ROM in the list that you get when you press F10. I saw the Instructions from this question:    I succeeded to do that and I changed my Windows, but now I can't boot Windows automatically – I have to press F10 to select my hard drive.  I enabled Secure Boot, but I can't find the hard drive on the F10 list. What can I do to get it back and boot Windows automatically?


Total combinations from number of unique combination?

How can you find count of the total combinations possible if you have the count of unique combinations? Suppose I need to form a sum of $3$ using $\{1,2\}$ Unique combn. $(1+1+1)$, $(1+2)$ hence '$2$' unique but total is '$3$' i.e, $(1+1+1)$, $(1+2)$, $(2+1)$ I know the elements used to make the combination Note: Number of unique combinations (ie. 2 here) is known. How can I find the total number of combination given the unique combinations?


Standard Visitor UK Visa from USA (Indian National) - Sending documents for family

We are a family of 4 Visiting UK this summer.  We have submitted our application online, have our interview scheduled in next couple of weeks.    I have a question regarding sending the documents to VFS services in New York.  Should I buy 4 different shipping labels - one for each applicant or can I send all the documents and passport for 4 of us in one shipping label / envelope?


In quantum mechanics I learned about Hermitian operators and eigenstates. It seems that Hermitian operators are always mentioned together with eigenstates. Why is that so? Does it mean that a Hermitian operator acting on a wavefunction always give a corresponding eigenvalue and eigenfunction?


I'm brand new- An Ubuntu convert- and I've been able to so far figure out how to burn the OS onto a DVD, and also how I can get it onto a thumb drive. I've even gotten it to work on both.  However, what I am concerned with is this: Can I continue to run Ubuntu ONLY via my thumb drive, and if so, when I get the screen telling me I can either "try Ubuntu" or install it, which do I choose? I've only done the former option, but if I do the latter, am I going to wipe my comp or will it actually only install on the thumb drive? I guess I'm wondering if I can treat my thumb drive like an external hard drive and just have it on there, so that I can use it when I want and then go back to my other OS when it's not plugged in.  Thanks for your help, all. Hopefully I'm making enough sense that you guys/gals know what I'm asking.


Why is Android refusing to resolve DNS records pointing to internal IP addresses?

I have a very strange behavior on an Android device (Nexus 7) when trying to access local network applications. Instead of getting the actual IP of the machine on LAN, the Android device gets the public IP, which means that Chrome, Firefox or any other browser simply shows the web page of the router.  I have an internal DNS server which handles the local networks. Doing ping from a PC works correctly:  $ ping s.pelicandd.com  PING pelicandd.com (192.168.1.15) 56(84) bytes of data. 64 bytes from front.pelicandd.com (192.168.1.15): icmp_seq=1 ttl=64 time=0.524 ms 64 bytes from front.pelicandd.com (192.168.1.15): icmp_seq=2 ttl=64 time=0.578 ms ^C   On an HTC One device (accessed with adb shell), it works well too:  shell@m7:/ $ ping s.pelicandd.com  PING pelicandd.com (192.168.1.15) 56(84) bytes of data. 64 bytes from front.pelicandd.com (192.168.1.15): icmp_seq=1 ttl=64 time=2.56 ms 64 bytes from front.pelicandd.com (192.168.1.15): icmp_seq=2 ttl=64 time=27.8 ms ^C   However, this is what I get when doing the same ping from Nexus 7:  shell@flo:/ $ ping s.pelicandd.com  PING pelicandd.com (90.78.26.42) 56(84) bytes of data. 64 bytes from LFbn-1-2441-42.w90-78.abo.wanadoo.fr (90.78.26.42): icmp_seq=1 ttl=64 time=2.56 ms 64 bytes from LFbn-1-2441-42.w90-78.abo.wanadoo.fr (90.78.26.42): icmp_seq=2 ttl=64 time=8.63 ms ^C   Instead of resolving to the internal IP, it resolves to the public one.  The network configuration is—except the IP address of the device—exactly the same on both devices: IP settings are set to Static, and DNS servers are the internal ones. Both Android devices are connected through Wi-Fi (unlike the PC). A major difference, however, is that Nexus 7 is using Android 6.0.1, while HTC One uses Android 5.0.2.  There is no nm-tool, dig or nslookup on Nexus 7. The device is not rooted.  The problem existed since I bought the device a few weeks ago, so it could hardly be the issue with DNS cache.  What can I do to further inspect this issue?


Can we make new flag responses more visible?

When looking at my flag-responses page, it's not always easy to tell what's new.  Sometimes flags take a while to resolve, so I might have one farther down the page that only now got resolved.  Moderators have always been able to leave messages for declined flags and now can leave them for helpful flags too.  If the moderators took the time to write them, we should try to read them.  But right now all I can do is scan the page and see if anything new jumps out at me.  For other types of responses (comments, edits, reputation changes, even changes in favorites), the new information is highlighted through styling (background color).  Could we do something like that for the flags page too?  Or provide some other way for users to see their newly-handled flags?


Should we change the positive asking record criteria for the Curious badge set?

Poking around the people's profiles to see how the  I keep seeing things like this:  It looks strange to have a 25/5 progress on a badge, but the dialog explains that what this user is missing is a positive record of asking. The  is: (total questions - negative questions - closed - deleted)/total questions >= 0.5  If you look at , it's hard to see how his asking record could be anything but exceptional. According to  his asking record is 0.875. The problem is that he asked many of his questions in the early days of the site that were well-received, but later deleted. Some were deleted after the question was . My suggestion is that we change the asking record formula: (total questions - negative questions - closed - early deleted)/total questions >= 0.5  The early deleted variable counts only questions deleted within 60 days of being asked. I picked 60 days because it's the dividing line between being able to . After looking through the list of people who would get the Curious badge on Stack Overflow with this change, I noticed a few things:  Many of them have self-deleted questions on their record. Often these are questions that were asked and basically ignored. After a few months, the original asker went back and deleted their question. It's hard to know what happened in each individual case, but my guess is that they never found a solution to their specific question and worked around the issue instead. (I have a few of those, but I'm not courteous enough to delete them.)  These users don't tend to ask the same question over and over again. I ran a similar test that excluded self-deleted questions. That group included a lot of cases of people asking a question, not getting an answer after a day or two, deleting the question, and asking the same question again. This strategy doesn't work if you wait two months to delete your first question.  Two mods (George Stocker and Gordon), Tim Post, and myself are on the list of users who would get a Curious badge under this system. On Meta Stack Exchange 5 current employees would be newly eligible for the badge. In my (admittedly biased) opinion, these are curious users.  I did some spot check on the lower end of the reputation scale. Every user I looked at fit my model of the ideal recipient of the Curious badge; they asked mostly upvoted questions with few closed questions. This change would add about 3286 new Curious badges on Stack Overflow, so there will certainly be a few exceptions I didn't find. But I think they are more than balanced by the clearly deserving users who will be awarded new badges.    Proposal: For the Curious, Inquisitive, and Socratic badges, don't count questions deleted 60 or more days after asking as deleted for the purposes of calculating asking record. These questions may still count as negatively scored or closed, if applicable. Days that include deleted questions, no matter when they are deleted, do not count toward the days asked criteria.   Modified Proposal: For the Curious, Inquisitive, and Socratic badges, don't count questions deleted or closed 60 or more days after asking as deleted or closed for the purposes of calculating asking record. These questions may still count as negatively scored, if applicable. Days that include deleted or closed questions, no matter when they are deleted or closed, do not count toward the days asked criteria. On Stack Overflow, that would add about 665 Curious badges, including two more for moderators (casperOne and 0x7fffffff) and one for an employee (Oded). On the opposite end of the reputation scale my spot checks are a bit muddier. Instead of a small number of deleted (and usually closed) questions, this list turns up users whose latest questions still aren't all that interesting. Even so, on balance a few extraneous bronze badges seem worthwhile in exchange for acknowledging truly curious users.


Condition for Maximum Power in the circuit

Maximum Power is transferred to a load when load resistance is equal to internal resistance of source. I want to know How ?  If I consider a source with internal resistance 'R' ,connected with resistance 'R' and current through circuit is 'i'. Then power is P1=$ (i^2)$2R. But if this source is connected to resistance 5R i.e internal resistance not equal to external resistance then Power P2= $(i^2)$6R, which is greater than P1. Then how the given statement above is true.


I don't understand how the expression ${e}^x \cdot \cos(x)$ is integrated.   On integral calculator the answer is given as $\frac{{{e}^x\sin{x} - {e}^x\cos{x}}}{2}$ and it is  so because by partial integration we get on the right side of the equation: $-\int{(f'\cdot g) \cdot dx}$ a $\int{{e}^x}\cdot \sin(x) \cdot dx$ twice.   Could someone explain as to why if the integral above shows  twice on the right side by doing partial integration then the integral of it is $\int\frac{{{e}^x}\sin(x)-{e}^x\cos(x)}{2}$?  Thank you!


Best Approach For Configuring Multiple .Net Applications

We have a suite of interlinked .Net 3.5 applications. Some are web sites, some are web services, and some are windows applications. Each app currently has its own configuration file (app.config or web.config), and currently there are some duplicate keys across the config files (which at the moment are kept in sync manually) as multiple apps require the same config value. Also, this suite of applications is deployed across various envrionemnts (dev, test, live etc)  What is the best approach to managing the configuration of these multiple apps from a single configuration source, so configuration values can be shared between multiple apps if required? We would also like to have separate configs for each environment (so when deploying you don't have to manually change certain config values that are environment specific such as conenction strings), but at the same time don't want to maintain multiple large config files (one for each environment) as keeping this in sync when adding new config keys will prove troublesome.


Captain America is able to throw his circular shield and have it return it to him like a boomerang.  Is this even possible according to physics (especially considering the ranges at which he uses the shield)?


How can I return a result set of records with duplicate columns in SQL

I have a database table in which each row has a first_name and last_name column, like so:   id   first_name   last_name |----|------------|-----------| | 1  | ted        | jones     | | 2  | mike       | johnson   | | 3  | ted        | jones     | | 4  | jan        | smith     | | 5  | anna       | white     | | 6  | jan        | smith     | |-----------------------------|   I want to find all records that are duplicates, i.e., the first and last names are identical. Given the data above, I want a result set like:   id   first_name   last_name |----|------------|-----------| | 1  | ted        | jones     | | 3  | ted        | jones     | | 4  | jan        | smith     | | 6  | jan        | smith     | |----|------------|-----------|   (More specifically, I'd like to get a count of such duplicate records, e.g., 2 [or 4, either would suffice] in this case.)  Is there a way to do this via SQL?


Replace Text Edit as the default text editor

I've seen questions  which don't quite solve my problem.  I'd like to make Sublime Text 3 the default file viewer/editor for all files that currently use textedit.  Most of these files can be command+i'd, but the ones that have no extension cannot. They give all sorts of permissions errors such as the ones in this image   Is there any way to just never use textedit, and instead set sublime as the default editor for all files?


Physical Interpretation of Kolmogorov 5/3 law

The Kolmogorov 5/3 law says that in turbulent flow, the energy $E(k)$ contained in a certain wave number k is proportionate to $k^{-\frac{5}{3}}$. How should one interprete this result in physical terms?  One way I considered is this. Energy is proportionate to velocity squared, the velocity of the fluid flow in the mode with wave number $k$ is proportionate to $k^{-\frac{5}{6}}$. Hence I can hope to think of this exponent as a measure of the fractal dimension of the velocity profile for turbulent flow.  Does this interpretation make sense or am I misguided?  Edit: My question is not so much of how one can justify the physical mechanism that results in the law, as the answer to the other question addresses. I am more interested in what it means to design an experiment that verifies this law.


laptop not booting to 20.04 usb made with rufus

Made bootable usb using rufus, new asus tuf a15 the bios is uefi without cms When selecting usb from boot menu theres a black screen for a second goes back to boot menu. How to boot into the usb.


I know that the following maths and factorials properties are useful in my problem but I don't really know how to actually get them into it a rigorous way:  $2\times 2^n=2^{n+1}$  $((n+1)!)/(n!)=n+1 $  So I did  $2((2n)!)≥2\times 2^n(n!)^2$  $2((2n)!)≥2^(n+1)(n!)^2$  But then I don't really know what to do for the $2((2n)!)$ and the $(n!)^2$; how to get them to have n+1


How to get server name from file information?

On the Details tab of the file properties in Windows, the last item under Owner is 'Computer'.  Does anyone know how to retrieve this information in C#?  I have a requirement to get the server name where a file was created.


Ubuntu 14.04 and Win8 problem; no to LiveDVD

"1Create a LiveDVD or LiveUSB of Ubuntu (>=12.04.2) 64bit ONLY.  2In your BIOS, disable QuickBoot/FastBoot and Intel Smart Response Technology (SRT). If you have Windows8, also disable FastStartup.  3Boot your PC using the LiveDVD or LiveUSB and choose "Try Ubuntu". If you get a Secure boot or signature error, you may wish to disable SecureBoot, then retry to boot the disk.  4Install Ubuntu from the Live CD/DVD or Live USB in the usual manner, then reboot the PC."  I have completed steps 1-3 but but my HP pavilion will not boot to Ubuntu CD. What can be the problem?


How can an international student get accepted into a PhD program in an area different from his MSc?

First off, I realize my question is too broad as it depends on the country, but I would be interested to hear mostly about the process in Canada and in western Europe, where it is common to complete a Master's degree before one's PhD.  I am an MSc mathematics student, and I am considering to switch to a different field for my PhD studies. I am thinking about certain directions in Computer Science or Electrical Engineering, which are completely unrelated to my current research.  Within my university such a switch is not uncommon, as the duration of a PhD has quite a soft upper bound, and a student coming from a different background can be accepted and simply required to learn the necessary basics of the new topic. Also, students who have received their MSc from the same university are not required to present official letters of recommendation when applying for a PhD, and the acceptance depends pretty much solely on the new advisor.  However, I imagine such a process would be much more complicated when applying to a different university, especially in a different country, as the department (or the potential advisor) has no way to evaluate the student's potential in the new field (assuming his MSc has nothing to do with the new field), and the student can't present letters of recommendation from researchers in said field.  Are such cases common? Are students coming from a different background at a significant disadvantage when competing with applicants from the same field, and how could one raise their chances of acceptance?  Thanks!


One of the answers in a reading exercise in my class today was:   100,000,000,000,000,000,000   ... which was the value of the highest denomination note ever issued. It was a 100,000,000,000,000,000,000 Pengo note, issued by Hungary in 1946. The students in my class wanted to know how they could say that last sentence in words in English. So I told them that I didn't know. They pointed out to me that if they wanted to read this bit of writing to someone they'd want to be able to use the words. Fair point.  Can anyone help?  [In case you're interested, a 100,000,000,000,000,000,000 Pengo note was worth about $0.20!]


How long before Ubuntu version no longer works?

I am currently at 15.04. I want to upgrade to a stable version soon, but after I finish some projects I am working on every day. I assume these projects will take another 6-8 weeks, but my system is now complaining about system errors and that there are no software updates for this version.  I can still use my computer, but how long will it will take before this all comes crashing down? Do I have enough time to finish my projects, or should I update immediately?


NullPointerException on method (NativeMethodAccessorImpl.invoke0(Native Method)

I'm creating a scheduled method to create last month invoices (currently set to every 5 seconds for testing purposes). I'm getting a NullPointerException on the line where I'm trying to get shiftServices from my shiftServiceService.  @Scheduled(cron = "*/5 * * * * *")     public void createLastMonthInvoices() {         List<Client> clients = clientService.getClientList();         System.out.println("Clients size: " + clients.size());         for (Client client : clients) {             System.out.println("Client ID: " + client.getId());             List<ShiftService> shiftServices = shiftServiceService.getLastMonthShiftServicesByClient(client.getId());             if (!ObjectUtils.isEmpty(shiftServices)) {                 System.out.println("Services size: " + shiftServices.size());         }     } }   Here is the shiftServiceService method itself.  public List<ShiftService> getLastMonthShiftServicesByClient(Long clientId) {         Specification<ShiftService> spec = where(null);         spec = spec.and(client(clientId));         spec = spec.and(lastMonthServices());         spec = spec.and(scheduledServices());          return shiftServiceRepository.findAll(spec);     }   clientId is not null and outputs correctly, but the function itself is giving me an error like this:  java.lang.NullPointerException: null     at com.bitweb.syda.service.invoice.InvoiceService.createLastMonthInvoices(InvoiceService.java:40)     at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.base/java.lang.reflect.Method.invoke(Method.java:566)     at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)     at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)     at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)     at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)     at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)     at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)     at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)     at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)     at java.base/java.lang.Thread.run(Thread.java:834)


Is it possible to have site-specific badges?

All badges are global across the SE network (except for some Area51-specific ones) however each site is different so is it possible to have some site-specific badges created aimed at encouraging useful content on each site?  I'm not fully aware of the various site-specific content available on other SE sites, but speaking on the site I'm part of () we have a feature where Balsamiq mockups can be posted directly within questions / answers. These greatly enhance the question as there is only so much you can get over with a textual description of an interface layout. However this feature isn't utilized as much as it could be. I'm starting to lose count of the number of comments we are leaving against posts stating 'can you provide a screen mockup so we can understand what you're referring to' or suchlike. By having a badge available such as 'create a Balsamiq mockup for a question' or 'Create a balsamiq mockup for an answer' it should hypothetically help encourage people to use this feature, thereby enhancing and potentially improving the question / answer quality.  I'm sure other sites have specific features available to them that are in place to improve the quality of questions/answers, so is it possible (or recommended) to provide site-specific badges to help update of these features?  How these badges would be chosen (and by whom) and what would qualify for achieving them is a different issue really, my question is mostly around whether or not it is possible - or even recommended - to have site-specific badges.


Should the bullet trajectory calculated by server or by client?

In a FPS game like Battlefield or Arma, when playing online, should the bullet trajectory be calculated by the server or by the client?


Let $f:(0,\infty)\rightarrow\mathbb{R}$ be differentiable and let $b$ be a real number. Prove that if $f'(t)\rightarrow b$ as $t\rightarrow\infty$, then $\frac{f(t)}{t}\rightarrow b$ as $t\rightarrow\infty$.  Median Value Theorem: If $f$ is continuous and differentiable, then $\exists c$ such that $a<c<b$ and $f'(c)=\frac{f(b)-f(b)}{b-a}$. So when $c\rightarrow\infty$, $a,b\rightarrow\infty$. How do I get $\frac{f(t)}{t}$?


Confusion regarding the principle of least action in Landau & Lifshitz "The Classical Theory of Fields"

Edit: The previous title didn't really ask the same thing as the question (sorry about that), so I've changed it. To clarify, I understand that the action isn't always a minimum. My questions are in the points 1. and 2. below.  I understand that "principle of least action" is somewhat of a misnomer, since we find that to determine the path taken by a system, we need only impose the condition that the action be stationary, i.e., that $\delta S$ should vanish to first order for small variations of the path, and this leads to the Euler-Lagrange equations. In The Classical Theory of Fields, Landau & Lifshitz discuss the relativistic action for a free particle:  So for a free particle the action must have the form $$S = -\alpha \int_a^b ds$$ (...) It is easy to see that $\alpha$ must be a positive quantity for all particles. In fact, as we saw [earlier], $\int_a^b ds$ has its maximum value along a straight world line; by integrating along a curved world line we can make the integral arbitrarily small. Thus the integral $\int_a^b ds$ with the positive sign cannot have a minimum; with the opposite sign it clearly has a minimum, along the straight world line.  There is also a footnote, addressed a couple of paragraphs earlier, but which is relevant:  Strictly speaking, the principle of least action asserts that the integral $S$ must be a minimum only for infinitesimal lengths of the path of integration. For paths of arbitrary length we can say only that $S$ must be an extremum, not necessarily a minimum.  I have two questions regarding this:  How is the condition "the action must be a minimum for infinitesimal displacements" formulated? I've never heard of that outside of Landau & Lifshitz's books, and in Mechanics they mention it as well but doesn't go into detail. Is this discussed a bit more somewhere?  If for the whole path the action only needs to be stationary, how can we make the argument for the negative sign? If the action had to be a minimum then it would make sense, but surely the fact that $\delta S$ = 0 isn't affected by an overall sign?


Can I exclude characters from understanding my magically understandable speech from the monk's Tongue of the Sun and Moon feature?

The rules for the monk ability Tongue of the Sun and Moon state:     Starting at 13th level, you learn to touch the ki of other minds so that you understand all spoken languages. Moreover, any creature that can understand a language can understand what you say.   PHB, pp.79   The text says that this ability is something you learn to do, not something that simply happens to you, so it's not necessarily always on. Further, it seems logical to say that this is something you would do actively. That is, you could choose not to touch someone's mind, thereby excluding them from understanding you. You could also choose not to understand someone yourself, just in case they're telling , or using a subliminal trigger.  Assuming you can choose not to touch someone's mind, let's reason further. Suppose you're speaking and don't know that there is someone listening in nearby. Would they understand you, i.e. is the default that you are or aren't touching someone's mind? Similarly, if you are speaking to a large group of people, would you have to focus on all of them at once for them to understand you? Would this take effort? Is there a range?  My questions are:   Can you exclude some characters from understanding you while allowing others to do so? Can you decide not to understand someone who is speaking?   Basically, these boil down to: Can you choose not to touch someone's mind?  Then, assuming that the answer to the above is yes:   Do you have to know someone is listening in order for them to understand you? Is there a limit to the number of people you can affect? A range?


import java.net.*; import java.io.*; import java.util.Scanner;  public class Rand {     public static void main(String[] args) throws Exception     {         System.out.printf("Integer Generator\n(c) First Name Last Name, 2014 All Rights Reserved\nNumbers Supplied by https://www.random.org/, This Connection is SSL protected by COMODO.\nGenerated numbers will be stored in output.txt\nWrite the quantities:   \n");         Scanner in=new Scanner(System.in);         int p=in.nextInt(), m, n;         while(true)         {             System.out.println("Write the Maximum number:   ");             m=in.nextInt();             System.out.println("Write the Minimum number:   ");             n=in.nextInt();             if(n<m) break;             System.out.println("Maximum is smaller than Minimum, Try again.");         }         PrintWriter writer=new PrintWriter("output.txt");         String[] inputLine=new String[p];         boolean b=false;         int i=0;         while(i<p)         {             b=false;             HttpURLConnection c=(HttpURLConnection)new URL("https://www.random.org/integers/?num=1&min="+n+"&max="+m+"&col=1&base=10&format=plain&rnd=new").openConnection();             c.setRequestProperty("Accept-Charset", "UTF-8");             c.setDoInput(true);             c.setDoOutput(false);             c.connect();             BufferedReader out=new BufferedReader(new InputStreamReader(c.getInputStream()));             inputLine[i]=out.readLine();             c.disconnect();             for(int j=i-1; j>=0; j--)             {                 if(i==0) break;                 if(inputLine[j]==inputLine[i])                 {                     inputLine[i]=null;                     b=true;                     break;                 }             }             if(b) continue;             writer.println(inputLine[i]);             i++;         }         writer.close();     } }   I programmed this code as a mini beginner project(Forgive me if this has an easy solution, I'm a 7th grader, please don't give me deductions)  I made it to give a sequence of numbers randomly without the same numbers repeating.  ex)      1      3      5      6      4      2 if quantity is 6, maximum is 6, minimum is 1.  However, it comes out like this:      4      1      6      4      4      1  What's wrong with this? Please give me an explanation.


I am trying to include some boxes around numbers in a table. I am using the method exactly described on the answer to question below:    The issue is that the first cell of the area surrounded by the box gets an extra space (if you see the example above you will see it). That's quite annoying. Why does it happen? How to solve it?


How do I get usb 3.0 driver working or check that it is already working

# lsmod |grep xhc   nothing here but in dmesg:  # dmesg |grep xhc [    0.650446] xhci_hcd 0000:00:14.0: xHCI Host Controller [    0.650450] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 1 [    0.651518] xhci_hcd 0000:00:14.0: hcc params 0x200077c1 hci version 0x100 quirks 0x00109810 [    0.651523] xhci_hcd 0000:00:14.0: cache line size of 64 is not supported [    0.651580] usb usb1: Manufacturer: Linux 4.2.0-25-generic xhci-hcd [    0.659081] xhci_hcd 0000:00:14.0: xHCI Host Controller [    0.659083] xhci_hcd 0000:00:14.0: new USB bus registered, assigned  bus number 2 [    0.659105] usb usb2: Manufacturer: Linux 4.2.0-25-generic xhci-hcd [    0.969678] usb 1-5: new full-speed USB device number 2 using xhci_hcd [    1.269906] usb 1-6: new low-speed USB device number 3 using xhci_hcd [    1.722308] usb 1-11: new high-speed USB device number 4 using xhci_hcd [ 3487.664191] usb 1-1: new high-speed USB device number 5 using xhci_hcd [ 3555.543441] usb 1-1: reset high-speed USB device number 5 using xhci_hcd   is it already working but built-in in the kernel?  #locate xhci /lib/modules/4.2.0-16-generic/kernel/drivers/usb/host/xhci-plat-hcd.ko /lib/modules/4.2.0-22-generic/kernel/drivers/usb/host/xhci-plat-hcd.ko /lib/modules/4.2.0-23-generic/kernel/drivers/usb/host/xhci-plat-hcd.ko /lib/modules/4.2.0-25-generic/kernel/drivers/usb/host/xhci-plat-hcd.ko /usr/src/linux-headers-4.2.0-16/... ...


How prevent LXDE to start at boot.  I prefer to start ubuntu server 16.04 without LXDE running so it coms with the command prompt afther boot. Start LXDE with the command startx. So how can i prevent that LXDE is started at boot time.  Tanks, Ian


I want to execute a script once an hour from 20:00 to 08:00. Would the following work?  0 20-8 * * * location_of_script_to_run   I'm currently using the following:  0 20,21,22,23,0,1,2,3,4,5,6,7,8 * * * location_of_script_to_run   Also, is there a way I can test this without having to actually wait? I imagine I'd need to temporarily alter the time on the system to trigger the execution.


Can files/directories deleted with rm be restored?

Is it possible to restore files/directories which are deleted from terminal using rm and rm -r?. If a file is deleted from graphical interface, it could be restored from trash, but how do you restore a file if it is removed using the rm utility?.


Getting DISTINCT objects from List based on ONE PROPERTY, username

I have a MyUser object defined in my code with several properties...  public class MyUser {     public Guid UserId;     public string EmailAddress;     public string UserName; }   Then I have a List of these MyUser objects....   List<MyUser> userList   How do I get rid of all duplicates based on only ONE PROPERTY of each myObject, such as UserName?   So basically if I have a List of 100 of these MyUser objects, I only want ONE occurrence of each UserName. So, if the UserName shows up more than once, remove the duplicates and keep only one object per UserName. In the end, I'll have a list that only has unique usernames (along with the other properties).  I thought I could do it with LINQ Distinct, but Distinct doesn't allow me to tell it to only consider ONE property.


At the top bar "~1 suggested pending approval" is shown in spite of no actual suggested edit pending

Currently I've faced this issue. on Hinduism.SE I see 1 suggested pending approval:    But clicking on which the page says:     This queue has been cleared! If you're looking for more to review, view all review queues.    Also review page says 0 suggested edits:    Note that this is not issue that before I clicked on 1, there was one suggested edit pending and when I clicked, it is already reviewed. Because I've reloaded page many times, even after 10 minutes I'm still getting 1 notification on top bar in spite of there is not any pending suggested edit approval.


Given three polynomials $a(x), b(x)$, and $c(x)$ satisfying $\gcd(a(x), b(x), c(x))=1$

Given three nonzero polynomials $a(x), b(x)$ and $c(x)$ satisfying $\gcd(a(x), b(x), c(x))=1$.  Please help me prove that there exists six polynomials $f(x), g(x), h(x), u(x), v(x), w(x)$ such that  $$\begin{vmatrix} a(x) & b(x) & c(x) \\  f(x) & g(x) & h(x) \\  u(x) & v(x) & w(x)  \end{vmatrix}=1$$


stack = ['','','','','','']    global first    global last    first = 0    last = 0    print(stack)    while True:        def push():            if 0 <= last:                stack[last] = 'D'                last = last + 1                if last == 6:                last = -1            else:                print("The stack is full.")                print(stack)         def pop():            stack[last] = ''            last == stack[last-1]            print(stack)            if first == last:                print("The queue is empty")        a = input("Push or pop. ")        if a == 'push':            push()        elif a == 'pop':            pop()   I've assigned last as a global variable yet I get this error UnboundLocalError: local variable 'last' referenced before assignment. Considering I've made last a global variable I don't understand why the error is suggesting otherwise, any solutions?


Any travel site for medium/long distance multimodal comparison? (Train then plane etc.)

I am trying to get from one minor city (X) in Europe to the other (Z). There are many options. I could train for an hour to X, then fly to Y, then train to Z. Or I could train from X to Z, or I could, bus to other airport W, fly to other airport Q, then train Q to Z, etc. etc.  Many website (e.g. skyscanner) will show me all the flights. Some show train sites will show me how to get from A to B via train (maybe by bus).  Is there any site that links them all together? So I enter a city/town name, and it tells me all the options for how to get there. Price is a factor, but not the main factor.


set password to not asked on login via the command line

how do i set the password settings of a user (named: interface) to not asked on login via the command line on ubuntuMATE?  i need to do this via the command line because the screen resolution on the raspberry pi is a very low 420x360 making doing it via the GUI impossible since it doesn't display fully.


What are the limits of the Room of Requirement?

Can the Room of Requirement provide anything if needed? For example:   James Potter wanted to hide from Voldemort, it would have served as a perfect hiding place. Harry Potter wanted all the Hocruxes, he should have gone straight to the room of requirement where he would have found all the Hocruxes along with the Sword. All the muggle borns of the wizarding community could have taken refuge in the room of requirement. Can someone meet a dead person in the room of Requirement if needed? Would it have been possible for Harry to go in past in order to see Dumbledore for the explanation of many things? Can the room duplicate something? For instance, Harry needed the Elder wand; with Voldemort having it, could he still get it? Someone wishes to be knowledgeable than Dumbledore, would the seeker find his desired wish by finding books and things?   Who created the room of requirement (surely not Salazar)? Was it beyond Dumbledore's magic to create such a place?


Gearing             14-Speed Shimano A070 STI Crankset            Prowheel Ounce 42/52T Double Chainring Alloy Crankset Shifters            Shimano A070 STI Front Derailleur    Shimano Claris Rear Derailleur     Shimano A070 Brakes              Tektro Dual-Pivot Caliper Brakes Brake Levers        Shimano A070 STI  Above is what I currently have. I am looking to convert from drop bar to flat bar to use the bike as a casual fitness and commuter bike. All I know is that some parts are road bike specific and may need replacing if I want the conversion done. I hear that the front derailleur, shifters/brake levers (obviously since it currently has STI) and the bar it self. Is there anything else that needs to be changed? I would like someone who has more knowledge in bikes than me to possibly tell me what parts from the above mentioned list needs to be changed. I am not looking to do any upgrades. Just looking for cheap budget parts since it will just be a leisure bike.  Thank you all  Sincerely  Tom.


Unable to update ubuntu 14.04 LTS by using 'sudo apt-get update'

When I'm trying to update ubuntu 14.04 LTS, I got this error message:  E: Malformed line 1 in source list /etc/apt/sources.list.d/virtualbox.list (dist)   E: The list of sources could not be read.     Contents of /etc/apt/sources.list.d/virtualbox.list:  deb download.virtualbox.org/virtualbox/debian trusty contrib non-free


Is it safe to use the command apt-get autoremove in this particular scenario?

The last time I used sudo apt-get autoremove, nearly every important display driver or parts got deleted. This made me very squeamish about using the command again. However, each time I install something or use apt-get update the terminal reads:   The following packages were automatically installed and are no longer required:   devilspie libturbojpeg:i386 libxrandr-ltsr2 language-pack-kde-en   kde-l10n-engb language-pack-kde-en-base libxv1:i386 libllvm3.2   libllvm3.2:i386 linux-generic-lts-raring Use 'apt-get autoremove' to remove them.     I tried the command clean and the messages stops displaying for a while. My question is whether it's safe running the autoremove command, or will I lose everything once again? Is there a way of checking how safe it is to use autoremove in this particular (or any) case?


Colorizing your terminal and shell environment?

I spend most of my time working in Unix environments and using terminal emulators. I try to use color on the command line, because color makes the output more useful and intuitive.  What options exist to add color to my terminal environment? What tricks do you use? What pitfalls have you encountered?  Unfortunately, support for color varies depending on terminal type, OS, TERM setting, utility, buggy implementations, etc.  Here are some tips from my setup, after a lot of experimentation:   I tend to set TERM=xterm-color, which is supported on most hosts (but not all). I work on a number of different hosts, different OS versions, etc. I use everything from macOS X, Ubuntu Linux, RHEL/CentOS/Scientific Linux and FreeBSD. I'm trying to keep things simple and generic, if possible. I do a bunch of work using GNU screen, which adds another layer of fun. Many OSs set things like dircolors and by default, and I don't want to modify this on a hundred different hosts. So I try to stick with the defaults. Instead, I tweak my terminal's color configuration. Use color for some  (ls, grep, less, vim) and the . These commands seem to use the standard "". For example:  alias less='less --RAW-CONTROL-CHARS' export LS_OPTS='--color=auto' alias ls='ls ${LS_OPTS}'    I'll post my .bashrc and answer my own question Jeopardy Style.


Is the Higgs boson not responsible for most mass?

The video  argues that almost all the mass that we are made of doesn't come interaction with the , but rather that most of a nucleus's mass comes from the space between quarks (the ).  If the video is correct, then there really needs to be an easy-to-understand explanation for mass because science popularizers make us laypeople think that the Higgs mechanism is responsible for all the mass in the atoms and that would be of course very misleading.


We all know this magical mathematical constant.   My question being , how and why pi just shows up in every other physics derivation or formula or even statistics for that matter .    Is it just coincidence or some actual reason?


How to use or operate an ini file using C#. Like reading, writing section, keys, values. I heard about nin.dll(or something like that) but I unable to use it. Also i am using sharpdevelop and dot net version 4.0 Thanks in advance.


Species Identification - small insect: is this a bed bug?

I found this bug in my apartment in Chicago.  We had bed bugs in our house the previous year (but we thought we got rid of them).  This bug was very small - maybe 2 millimeters in length.  These photos are all of the very same bug (just different lighting).


How to find the formula for the sum of fractions like this? $$\frac{1}{1\times 2}+\frac{1}{2\times 3}+\ldots+\frac{1}{n\times (n+1)}=$$


How do I ignore files in Subversion?  Also, how do I find files which are not under version control?


I'm newbie in java and i need some help.I created a class;  public class asdd {     String name;     String Lastname;     int age;      public asdd(String value1,String value2,int value3){          this.name=value1;         this.Lastname=value2;         this.age=value3;     }  }   Then i wrote some code to do practic but i faced a problem with if control statement in below. Although input is "mike" my program bypasses if and runs else statement. Thanks.  import java.util.Scanner;  public class dd {      public static void main(String[] arguments){        asdd person=new asdd("mike","angel",21);       Scanner input= new Scanner(System.in);       String control=input.nextLine();        if (control==person.name)         System.out.println("hi baby");       else         System.out.println(person.Lastname);     }     }   Also i'm getting  error after run program.


Parse XML with Namespace using SimpleXML

I have this as xml:  <root xmlns:event="http://www.webex.com/schemas/2002/06/service/event">     <event:event>         <event:sessionKey></event:sessionKey>         <event:sessionName>Learn QB in Minutes</event:sessionName>         <event:sessionType>9</event:sessionType>         <event:hostWebExID></event:hostWebExID>         <event:startDate>02/12/2009</event:startDate>         <event:endDate>02/12/2009</event:endDate>         <event:timeZoneID>11</event:timeZoneID>         <event:duration>30</event:duration>         <event:description></event:description>         <event:status>NOT_INPROGRESS</event:status>         <event:panelists></event:panelists>         <event:listStatus>PUBLIC</event:listStatus>     </event:event>     ... </root>   How can I loop through all of the event:event nodes and display, for example, all of the event:SessionKey's?   This does not work:  $xml = new SimpleXMLElement($r); $xml->registerXPathNamespace('e', 'http://www.webex.com/schemas/2002/06/service/event');  foreach($xml->xpath('//e:event') as $event) {  var_export($event->xpath('//e:sessionKey')); }


Copy files to different location created one hour Ago

I want to create one batch file to copy files from one location to another which are created one hour Ago. I tried to use xcopy /d but it does not accept time.  Can you please suggest.  thanks.


Subsubsection: remove the newline (like paragraph)

Using the article document class, how can one remove the newline at the end of a subsubsection title?  I am using \documentclass{article}; I do not currently use titlesec or any of the alternatives; I do use fancyhdr.


Unable to delete dynamically created div

The user can delete new field input rows by by clicking on the ‘-‘ button for that particular row. The user also has the ability to add new field input rows. The JS code that I've written works for the existing rows, but it doesn't work for any of the new dynamically created lines that are added by clicking the '+' button.  I've tried changing   $(".remove-current-ing").click(function() {...}  to  $(".remove-current-ing").on('click', function() {...}  HTML code:

 Ingredients
         {% for ing in recipe.ingredients %}
             <input id="ingredients" name="ingredients" type="text" placeholder="Ingredient (one per line)" class="form-control validate" value="{{ ing|capitalize }}" required>
         {% endfor %}                  <button type="button" class="waves-effect waves-light btn add-ing">                      </button>                   <button type="button" class="waves-effect waves-light btn remove-ing">                      </button>
   JS code:   let ingCount = $(".ingredients").length;     // Add new line     $(".add-ing").click(function() {         // Clone line, insert before add/remove btns and clear existing values         $(".ingredients:first").clone().insertBefore(".add-ing").find("input[type='text']").val("");         // Ensures original line is never removed         ingCount += 1;     });     // Remove last line     $(".remove-ing").click(function() {         // Ensure that the first line can't be removed         if (ingCount > 1) {             $(".ingredients:last").remove();             ingCount -= 1;         }     });  /* Remove the current ingredient (edit_recipe.html) */ /* CODE THAT ISN'T WORKING ON DYNAMICALLY CREATED ROW */ $(".remove-current-ing").on('click', function() {     // Ensure that the first line can't be removed     if (ingCount > 1) {         $(this).parent().remove();         ingCount -= 1;     } });```   The .remove-current-ing button works on pre-exisiting rows and removes them, but it doesn't work on new dynamically created rows (nothing happens when pressed).


How do I make my shears be able to break iron bars in adventure mode?

I am trying to make a prison break minecraft map! One of the items to help escape are shears, to let them break bars. I know the command to let blocks break other blocks in adventure mode, the default is adventure mode, and the only mistake showing up is the iron bars! Here is my command: /give @p shears 1 0 {CanDestroy: [iron_bars]}


This is the errror, tried a few things but still to no avail.   java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference                                                                        at com.dllibrary.cart.SigninMainActivity$1$1.onDataChange(SigninMainActivity.java:56)                                                                         at com.google.android.gms.internal.zzegf.zza(Unknown Source)                                                                         at com.google.android.gms.internal.zzeia.zzbyc(Unknown Source)                                                                         at com.google.android.gms.internal.zzeig.run(Unknown Source)                                                                         at android.os.Handler.handleCallback(Handler.java:815)                                                                         at android.os.Handler.dispatchMessage(Handler.java:104)                                                                         at android.os.Looper.loop(Looper.java:194)                                                                         at android.app.ActivityThread.main(ActivityThread.java:5637)                                                                         at java.lang.reflect.Method.invoke(Native Method)                                                                         at java.lang.reflect.Method.invoke(Method.java:372)                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)  code for my sign in method       signin.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             final ProgressDialog mdialog = new       ProgressDialog(SigninMainActivity.this);             mdialog.setMessage("Please waiting");             mdialog.show();             table_user.addValueEventListener(new ValueEventListener() {                 @Override                 public void onDataChange(DataSnapshot dataSnapshot) {                     //check if user not exist                     if (dataSnapshot.child(phone.getText().toString()).exists()) {                         //Get User Information                         mdialog.dismiss();                          User user = dataSnapshot.child(phone.getText().toString()).getValue(User.class);                        if (user.getPassword().equals(password.getText().toString())) {                             Intent homeIntent= new Intent(SigninMainActivity.this, home.class);                             Common.currentUser = user;                             startActivity(homeIntent);                             finish();                         } else {                              Toast.makeText(SigninMainActivity.this, "Sign in failed", Toast.LENGTH_SHORT).show();                           }                     }else{                         mdialog.dismiss();                         Toast.makeText(SigninMainActivity.this, "User Does Not exist", Toast.LENGTH_SHORT).show();                     }                 }   line 56 is at "if(user.getPassword.equals)"


Can a lizardfolk monk use their bonus action to make an unarmed strike using their Bite trait?

I'm gonna be playing my very first D&D game pretty soon and I'm really excited. I'm playing a Lizardfolk monk, and I just finished my character sheet, but I was confused about something.  We're starting out at level 2. At level 2, the monk gets the Martial Arts feature, which lets them use a bonus action to make an unarmed strike. However, the Lizardfolk has a bite attack that can be used to make an unarmed strike that does 1d6 + Strength mod piercing damage.  Am I allowed to use my Bite as my lizardfolk monk's bonus-action unarmed strike? Or is that not allowed, since that's some different ability or something?


Why is $R^2$ so difficult to calculate for mixed models (both for the model as a whole and the fixed effects)?

I have been using a package to calculate $R^2$ values for mixed models. The documentation for the package has the following quote from Harry Singmann:     "The fact that calculating a global measure of model fit (such as $R^2$)   is already riddled with complications and that no simple single number   can be found, should be a hint that doing so for a subset of the model   parameters (i.e., main-effects or interactions) is even more   difficult. Given this, I would not recommend trying finding a measure   of standardized effect sizes for mixed models."   Why exactly is this the case?  More over I am interested in why finding $R^2$ for each individual predictor is problematic?  Edit: I'm also curious as to whether the squared semi-partial correlation for each predictor is also problematic.


Looking for high quality Koppen climate maps

I wonder if anyone can point me in the direction of high resolution Koppen climate maps for use in academic research. I want to accurately place c. 100 study sites from around the world in their respective climatic zones for a meta analysis I am conducting.


StackExchange.com logs me in automatically on the login page

When I go to the main stackexchange.com site, and login, then logout, after I try to login again, I am automatically logged in, without having to enter any account details.  Pics:    Then I press login:    Note, that I didn't fill out anything, it just logged me in. When I logout explicitly on the site, I get logged out, but I can still just click the login page and get logged in automatically, without needing to enter my details.  Notes:   I am using an own OpenID URL that delegates to SE's OpenID provider Browser: Chrome After logout local storage and session storage are empty. The following cookies are present: d, mc, __cfduid, __qca, __utma, __utmb, __utmc, __utmz, ASP.NET_SessionId, gauthed.   EDIT: If you closed this question, because it is a duplicate, please note that at the duplicate question the poster  on the SE provider to arrive at the auto-login page. In my case I did not have to click on any of the provider buttons, which means simply arriving at the login page will do an auto-login, essentally preventing logging in as any other user (which, if it is by design, is probably wrong)


Do I have to buy a 35/1.8 to get background blur or can I use the kit lens?

I have a Nikkon D3200 and it comes with a 18-55mm f/3.5-5.6 Auto Focus-S DX VR NIKKOR Zoom Lens.  I read that before I purchase a 35mm prime lens, I should set my lens to 35mm and then take pictures for a week to see how I feel.   I want to achieve bokeh or lens background blur so that I can focus on the person or object in focus. However I do not get that when setting my camera in aperture priority mode.   The lowest my kit lens can go is F/3.5, and the lens I want to buy is F/1.8  Will I ever see background blur with my kit lens or do i have to purchase the Nikkor 35MM F/1.8G ?


Predicates: in the WHERE clause or the JOIN clause?

Looking at "SQL Server 2008 Internals"1 by Kalen Delaney, on page 13, it states the following:     "The first step in producing such a plan is to normalize each query, which potentially breaks down a single query into multiple, fine-grained queries.  After the Query Optimizer normalizes a query, it optimizes it, which means that it determines a plan for executing that query."   It's been suggested to me by another DBA that performance can be improved for certain queries by moving WHERE clause predicates into the FROM clause, such that:  SELECT * FROM dbo.table1 t1     INNER JOIN dbo.table3 t3 ON t1.ID = t3.ID     LEFT OUTER JOIN dbo.table2 t2 ON t1.ID = t2.ID WHERE t1.CreateDate >= '2015-07-31 00:00:00';   would become:  SELECT * FROM dbo.table1 t1     INNER JOIN dbo.table3 t3 ON t1.ID = t3.ID         AND t1.CreateDate >= '2015-07-31 00:00:00'     LEFT OUTER JOIN dbo.table2 t2 ON t1.ID = t2.ID;   Apparently the implication for the first example is the query optimizer will perform the JOIN first, then apply the WHERE clause, which for complicated queries with large tables will not perform as well as if we manually re-write the query into the form presented in the second example.  Apparently this only applies to outer joins, i.e. if this were an inner join, the normalizer would in fact move the WHERE predicate into the FROM clause.  Can someone confirm this behavior?  Is there some documentation somewhere I can look at?  Can I see this in the execution plan?    1 - yes, I know this is ancient.


fontenc changes sans serif bold font in KOMA-script

Consider the following MWE:  \documentclass{article} %\usepackage[T1]{fontenc}  \begin{document}  \textbf{\textsf{Some text}}  \end{document}   The output of the above code is     and doesn't change if I uncomment the line  %\usepackage[T1]{fontenc}   Consider now the following MWE with scrartcl class instead of article:  \documentclass{scrartcl} %\usepackage[T1]{fontenc}  \begin{document}  \section{A section} \textsf{Some text} \end{document}      Uncommenting the line  %\usepackage[T1]{fontenc}   you get    As you can see, the sans serif font of the title is less  bold than without fontenc, while the normal text is not changed.  Does fontenc, combined with a KOMA-script class, load a different sans serif font, but only for bold face?


Can't boot from USB when installing Ubuntu

I downloaded Ubuntu 11.10 32bit and put it in on USB drive using Universal USB Installer from  .  I then restarted my laptop. I pressed Esc and chose "Boot Management", but there was no option for booting from USB. The only options I could see were boot from hard drive and boot from internal CD/DVD. What should I do?  I have already changed the boot order at BIOS and it still didn't work. My system is 64-bit, but does it matter if I want to install a Ubuntu 32-bit?


I recently installed Ubuntu on my laptop(Sony Vaio Duo 13). The laptop ONLY has two USB slots in the back, no disk drive. A bit later I realized that I still needed Windows for programs needed in University. I tried using rufus to make a bootable USB that had Windows 8.1 on it. I tested the USB on a friends laptop and it went right into the Windows installation. When I plug the USB into my computer it says that "My Sony could not read media(USB/CD)." I was a bit baffled by this so I made a bootable USB with Ubuntu on it. Ubuntu was able to start up in grub and gave me the option to install it. I reinstalled it to see if that was the case. It was not, I still could not boot to the USB with Windows on it. If I do not boot into Ubuntu, I get into the grub command line. I have also changed my BIOS setting around to each combination of possible differences, no help. I fear that I have deleted or corrupted something in my MBR. If anyone could help, that would be amazing, as I have not been able to fix this problem in days. Nothing on google, reddit or anywhere else has made any difference.  Thanks!


How do I ensure that figures appear in the section they're associated with?

Often floats may land quite a bit later in the document than the point they are created, sometimes after a section break.  Is there a way to force a new section to start on a new page, after any unplaced floats?


How do I develop for the Unity Control Center?

I found no source on how to create an entry in Unity Control Center. Is it even possible? What languages can I use?  Edit: I'm searching for a method to have an entry appear in the Unity Control Center, and to write a component or whatever that lives INSIDE this window. Not a launcher only solution.


Converting from EPSG 25833 to WGS 4326 using QGIS?

I have a layer of Brandenburg (Germany) in EPSG 25833 which I want to tranfrom to EPSG 4326. Similar to  to , I set the CRS to EPSG 4326 and go to export / save as to save this layer in 4326.  Now once I try to overlay this layer with a point shapefile of hospitals in Brandenburg taken from OSM (which is in EPSG 4326 by default) they do not match at all.  What am I missing?


How do I set class string variables with keyboard input?

I am working on a project where I have a class named dBase with getter and setter methods for fields such as first and last names. However, When I run the code, line 6 of the code portion is highlighted with a java.lang.NullPointerException error, which doesn't help me at all.  How do I make this work? Thanks, in advance  case 3: input.nextLine(); for (int i = 0; i < num; i++){ System.out.println("Enter first name of student " + (i + 1)); String firstN = input.nextLine(); roster[i].setfName(firstN); System.out.println("Enter last name of student " + (i + 1)); String lastN = input.nextLine(); roster[i].setlName(lastN);     }         break;


I have cretad a menu for edit a form in drupal...  Code:  function pricepackages_menu() {     $items = array();     $items['membership/packages'] = array(         'title' => t('Add Membership Packages'),         'page callback' => 'drupal_get_form',         'page arguments' => array('pricepackages_form'),         'access arguments' => array('access administration pages'),     );     $items['show/packages'] = array(         'title' => t('Manage Membership Packages'),         'page callback' => 'view_packages',         'access arguments' => array('access administration pages'),     );     $items['package/%/edit'] = array(         'title' => 'Edit Membership',         'page callback' => 'drupal_get_form',         'page arguments' => array('pricepackages_form_update'),         'access arguments' => array('access administration pages'),     );     return $items; }   3rd menu is for eidt purpose...  The codd to show form i worte is:  function pricepackages_form_update($form, &$form_state) {     $form['packagename'] = array(         '#type' => 'textfield',         '#title' => 'Package Name',         '#required' => TRUE,     ); }   Please let me know how can get the value of the id in the url :  URL :    I want to get the id 1 from the url and than want to add a select query... please let me know how can i get that value so i can wrote teh select query...  Also do i have to specify a new parameter in the pricepackages_form_update() or not?  Thanks in advance...


Resize partition without affecting other OSes in dual-boot

I wanted to resize (increase or decrease the partition size) the existing Ubuntu partition without affecting it and the other OS(es) installed in the machine.


Cheapest Way to Get to Europe--I'm Flexible

My brother and I are planning a trip to Europe from the US late summer/early fall.  I have Southwest airline points, and we are probably going all around Europe so specific airports and times are not really important.  What is the best way to search for the most economical flights?