Using the command line, how can I check if a *.ttf file contains a certain character?  I want to know if the font-file Ubuntu-R.ttf contains the U+2007 (FIGURE SPACE) character.

How can I find out which fonts on my system include coverage of a certain character, for example, U+2192?  I've tried looking in Character Map, but I don't see a way to query fonts by character, only characters by font.


When we type in emacs in Ubuntu's Terminal, it will show a list of apps or commands we can install.  I am not so interested in what it is particularly for emacs, but want to find out if there is a way to get a one line or longer description of each of the commands?  Such as  <some-command> emacs   and it will show  emacs24   The GUI version of emacs jove      A simplified version of emacs (non GUI) [...]

When I type "mc" on my 14.04 Ubuntu terminal I get a   The program 'mc' is currently not installed. You can install it by typing: sudo apt-get install mc   How can I get details about the program 'mc' before installing it? I want to confirm that that is the file I want, and not some other one.


I have an external 1.5TB hard-drive which I've been using for years, no back-ups.   I have several partitions on that hard-drive, one of which has all my data on (I cannot remember whether FAT32/NTFS), and another bootable partition.  I attempted to install UbuntuStudio via Startup Disk Creator, I incorrectly assumed it would only write to the mounted bootable partition. Once I realised my mistake I clicked cancel, Startup Disk Creator crashed and I killed the program.  Now all of my partitions bar the 'UbuntuStudio' created partition have disappeared. The operation only lasted a second, I am hoping my data is recoverable.  I followed: , which showed a list of partitions not able to be recovered, and some which could be. From the partitions of which I could list files, none were my data partition. There were two partitions of identical size (about 200GB) which I could not list the files of. I know the 'label'/name of my data partition, if only I could search for it.  I'm on the verge of despair here, bar committing a crime - I'm sure the Police would have no trouble recovering my data - I don't know what to do. To whoever helps, I owe my sanity to you.  Note: I would post my logs, but I made a further mistake of closing testdisk - the operation took about 12 hours.    To my knowledge my HDD is not 5.45 TiB, it is ~1.5 TB.  Any method which repairs the partition records in place is ideal, I do not have a separate external HDD for backing up my files.  Update: this is what I see:    Update:    Scan has finished, I would like to attempt to Add Partition using data from the screenshots, can someone please confirm my actions?   I do not have an external HDD and am attempting repair in-place, with testdisk if possible. Searching for 'testdisk add partition' is returning few relevant results, e. g.,   I am trying to get specific advice about recovering the partition layout, or recreating it if it's corrupt beyond repair.

About two weeks ago I had a problem with my PC that my brother wrote a question about at .  I still haven't solved the problem, so my PC is unusable now.  Now I think that it would be simpler to re-install both Win7 & Ubuntu than repair them, but there're some data on their partitions. I want to recover this data.  These partitions are not mountable for some reason. I don't know why.  sudo fdisk -l about the problematic partitions:     Device    Boot      Start         End      Blocks   Id  System /dev/sda1            2048     147912703    73955328   83 Linux /dev/sdb2            206848   174079999    86936576    7  HPFS/NTFS/exFAT   And in GParted:      And the error of the mount command:  Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   And the exact same message for /dev/sda1  How can I recover my data from those HDDs?  EDIT     I have tried to specify the type of the drive:  $ sudo mount -t ext4 /dev/sda1 /olddisk mount: wrong fs type, bad option, bad superblock on /dev/sda1,        missing codepage or helper program, or other error        In some cases useful info is found in syslog - try        dmesg | tail  or so $ sudo mount -t ntfs /dev/sdb2 /olddisk NTFS signature is missing. Failed to mount '/dev/sdb2': Invalid argument The device '/dev/sdb2' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?   EDIT     sudo ntfsfix /dev/sdb2 returns:  Mounting volume... NTFS signature is missing. FAILED Attempting to correct errors... NTFS signature is missing. FAILED Failed to startup volume: Invalid argument NTFS signature is missing. Trying the alternate boot sector Unrecoverable error Volume is corrupt. You should run chkdsk.


how to declare 8 variables and get the total Sum,as you can see from the picture i created the 3 store procedures but dont know how to do the rest(Churn_MTD_Current_Year+Churn_MTD_Previous_Year+Churn_MTD_Less_Than_Previous_Year) then add it to (goal 2016+2015+less than 2015) then create temp table and store it there!!!!

how to Create A SP with table variable and execute 3 SP  statements in the same statement .  exec [dbo].[sp_KPI_Churn_MTD_Current_Year] exec [dbo].[sp_KPI_Churn_MTD_Previous_Year] exec [dbo].[sp_KPI_Churn_MTD_Less_Than_Previous_Year]  Results should be as in the picture Please see Image:


In homologous recombination (Holliday model), the last process i.e resolution can occur in two ways (horizontl and vertical cuts) leading to formation of either "splice" or crossover products or "patch" or non-crossovers product (as shown in the image).  The two possible products confuse me with what are crossovers. I could not understand why the "patch" product (Fig. (g) in the image) is called a non-crossover. Is it because one strand of both the homologous helices are same? Also please do explain what is the hetero-duplex in this model?

In this figure out of the two heteroduplexes formed one is considered to be non-recombinant product(left) and the other recombinant product(right). My question is despite the exchange of middle DNA segment why is the right heteroduplex considered a non-recombinant product or patch. I've been reading two books:    By Nancy Lynn Craig, Rachel Green, Orna Cohen-Fix, Carol Greider, Gisela Storz, Cynthia   By Burton E. Tropp   both had the same illustration and descrpition.


I am using Ubuntu 14.04 LTS and I cannot find workspaces.  I have done searches in the Dash for it, I have tried 'sudo apt-get install workspaces' in a terminal.  All without success, help required!

It appears that Unity on Raring only comes with a single virtual desktop (aka workspaces) by default, and CCSM's Wall plugin has no way to add more. Is this configurable at all?


I can't find where to find the flags raised by me.   I saw this link   But there is no flags count below my profile views.  Where can I check my flags?

I cannot find the flagging summary on my user profile.  I have seen many questions about flagging system: , , , etc.  I know the results of my flags are not of my business and moderators are responsible for the follow up, but I would like to see the summary as there are other things involved, such as Deputy and Marshal badges.


I am stuck with the following problem that says:  If $n$ is a positive integer such that the sum of all positive integers $a$ satisfying $1 \le a \le n$ and GCD $(a,n)=1$ is equal to $240n,$ then the number of summands ,namely,$\phi(n),$ is  $120$ $124$ $240$ $480$   MY TRY: Just for understanding, if  I take $n=5,$then $a_i$'s such that gcd $(a_i,5)=1$ and $\sum a_i=240\times 5$. But, $a_i$'s can only be $1,2,3,4$ ,since $n=5$. Now, I do not know which way to go. Can someone explain? Thanks in advance for your time.

If $n$ is a positive integer such that the sum of all positive integers $a$ satisfying $1\leq a\leq n$ and $\gcd(a,n)=1$ is equal to $240n$ then the number of summands namely $\phi(n)$ is    120 124 240 480   My attempt:   If $n $= $p_1^{q_1}p_2^{q_2}...p_k^{q_k}$ where $p_1, p_2,...p_k$ are primes.  $240 n = \frac{n(n+1)}{2} - \frac{p_1^{q_1+1}-1}{p_1 -1}\frac{p_2^{q_2+1}-1}{p_2 -1}... \frac{p_k^{q_k+1}-1}{p_k -1}  +1 $  From here, I was not able to proceed. Guesswork tells me that the number has to be 480 because the sum is $240n$.


I feed the ocelot and the hearts come up but it doesn't change into anything, it just stays an ocelot. Can anyone help me on what I'm doing wrong

I'm having the same trouble with the Ocelot. It was walking towards me and I right clicked it lots of times with the raw fish in hand, but it still only goes into breeding mode and it won't tame them at all.


Inside a function, I'd like to change the value of a global variable that is specified by the function's argument.  A = 1; B = 2; C = 3;  function myFunction(variable) {     variable += 10; }  myFunction(A); myFunction(B); myFunction(C);    I'm looking for these results:  console.log(A);   // 11 expected console.log(B);   // 12 expected console.log(C);   // 13 expected   I can't output the new value via a return statement because it's computed inside the callback function of a post request.  How to achieve this?

The primitive types (number, string, etc.) are passed by value, but objects are unknown, because they can be both passed-by-value (in case we consider that a variable holding an object is in fact a reference to the object) and passed-by-reference (when we consider that the variable to the object holds the object itself).  Although it doesn't really matter at the end, I want to know what is the correct way to present the arguments passing conventions. Is there an excerpt from JavaScript specification, which defines what should be the semantics regarding this?


I'd like to prove   $$\sum_{n= -\infty}^{\infty} \frac{1}{(t+n)^2} = \frac{\pi^2 }{\sin^2(\pi t)}$$  by using the Poisson summation formula. There is a way to do it by firstly taking the Fourier transform of $f(x) = 1 - |x|$ for $|x|\le1$ and $f(x) = 0$ for $|x|>1$. There's a next step which I can't work out, and then you apply the Poisson summation formula.  I get the Fourier transform of f(x) as $\frac{2(1-cosy)}{y^2}$ but can't work out the next step so I can apply Poisson summation formula.   There's also a comment in a previous post back in April by user Lost about having done it. But I can't find any tips. I know it's possible.  Thanks in advance.

Now we want to prove: $$\sum_{n=-\infty}^{\infty}\frac{1}{(n+\alpha)^2}=\frac{\pi^2}{(\sin \pi \alpha)^2}$$ $\alpha$ >0 and not an integer. According to poisson summation formula $$\sum_{n=-\infty}^{\infty}f(x+n)=\sum_{n=-\infty}^{\infty}\hat{f}(n)e^{2\pi inx}.$$ So, if we let $f(x)=\frac{1}{x^2}$, then $$\sum_{n=-\infty}^{\infty}f(x+n)=\sum_{n=-\infty}^{\infty}\frac{1}{(n+x)^2}$$ Therefore, if we can prove that $$\sum_{n=-\infty}^{\infty}\left(\int_{-\infty}^{\infty}\frac{1}{x^2} e^{-2\pi inx}dx e^{2\pi inx}\right)=\frac{\pi^2}{(\sin \pi x)^2}$$ Then it will be done. But I don't know how to prove $$\sum_{n=-\infty}^{\infty}\left(\int_{-\infty}^{\infty}\frac{1}{x^2} e^{-2\pi inx}dx e^{2\pi inx}\right)=\frac{\pi^2}{(\sin \pi x)^2}$$ Who could give me some hints? Thanks!


I would like to run a never-ending command (such as play a mp3 file in loop)  for a period of length T. I put the command in a shell script my.sh: #! /bin/bash vlc /path/to/my.mp3 # will play the file in loop till I terminate it.  and then I try to run it my.sh &  pid="$!" # need to get the pid of the vlc process. sleep 2.5h kill $pid   It seems that it kills only the process running the shell script, not the process running the command in the script. How can I kill the process running the command in the script? Thanks.

I want know how I can run a command for a specified time say, one minute and if it doesn't complete execution then I should be able to stop it.


I have a mesh and when I access edit mode I can select a vert, but how can I see what verts it is? Because the "Verts:1/2712" will always stay 1. I don't want to see how many I have selected, but the number of the one I have selected. So when I have a mesh with 2715 vertices, and when I select the last, then I want to see: '2715'.  A screen of when I want to see the vert:

I am try to do something based on the ID of a vertices. I want blender to show me the vertices ID. How can I have blender show me the ID in the viewport? I do not see an option in the Mesh Display tab.


I have got a relay that doesn't release immediately after power is cut off. What could be the possible causes of this?

I'm using a flyback converter (220-100V to 19vdc) to power an electronics unit. But it doesn't discharge fast enough, this causes some relays to stay energised for a second or two after power supply is cut off which is not ideal. Any ideas on how to make the flyback converter discharge almost instantly? Also, what can cause a relay to stay energised after supply is out?


How do you prove this question? I was thinking proving contrapositive. But I was stuck..Thanks guys.

Let $a$ and $b$ be reals with $a<b$. Show that there are infinitely many rationals $x$ such that $a<x<b$.  My plan of action was to assume that $x$ is the smallest such rational and find another rational in the interval $(a, x)$, but I am struggling to make it work. A hint will be much preferred to a full solution.


So this doesn't work:      List<Object> j;       List<String> k =new  List<String>();     j =  k;   Nor does this:      j = (List<Object>)k;   or this:     k = j as List<Object>;    It seems like these ought to be assignable, but not sure how is the right way to achieve the result

It seems that a List object cannot be stored in a List variable in C#, and can't even be explicitly cast that way.  List<string> sl = new List<string>(); List<object> ol; ol = sl;   results in Cannot implicitly convert type System.Collections.Generic.List<string> to System.Collections.Generic.List<object>  And then...  List<string> sl = new List<string>(); List<object> ol; ol = (List<object>)sl;   results in Cannot convert type System.Collections.Generic.List<string> to System.Collections.Generic.List<object>  Of course, you can do it by pulling everything out of the string list and putting it back in one at a time, but it is a rather convoluted solution.


I suspect the answer is "No", but felt I should ask anyway. Given that the everything we know about the Star Trek "universe" has changed with the Abrams reboot, I was wondering how this would affect the rest of the galaxy, especially the nearly omnipotent species like the Q or Organians. To keep the question specific, though, let's limit it to the Q Continuum.  Have we seen anything on-screen or in EU materials that would indicate the Q are subject (or immune, even) to widespread changes in the timeline?  I know that we've seen Q himself interact with alternate timelines on a couple of occasions, but those were localized events involving the Enterprise-D or Voyager crews. When it comes to large-scale alterations like the Mirror Universe, I don't think we've seen the Q involved...

As shown in various episodes ("Mirror, Mirror," "Phantasms," etc.), other universes exist, oftentimes containing the same characters, albeit in different situations than in the prime universe. I'm curious, though, whether individuals that apparently exist outside of the multiverse, such as members of the Q, would not be duplicated elsewhere. It seems reasonable to me, but I'm not sure.


If there are two objects moving relative to each other at a constant velocity, is there any experiment the bodies themselves can do to determine which one is moving? EDIT: The comments say "NO". So please can anyone explain this:  If we could make bodies produce sound and while one produces other calculates the received frequency. So, does Doppler effect give same frequencies for both the cases or is there a way to perceive the difference?

I've read that it's just as correct to think of A moving toward B (ie. A doesn't move, but B does) as it is to think about B as moving toward A (again, A doesn't move, but B does) or as the two moving toward each other.   If I imagine a universe in which only two objects exists - then that seems like it would be the case. However, in that universe there isn't really a point of reference to say whether one object isn't moving.   Is there a useful and accurate way to think about these kinds of relations?   Thank you -Hal.


I am trying to prove this:  Let $\sigma$ be a non-identity element of $S_{n}$. If $n \geq 3$ show that $\exists \gamma \in  S_{n}$ such that $\sigma\gamma \neq \gamma\sigma$. Hint: Let $\sigma*k=1$ where $k \neq 1$. Let $m$ not be an element of $\{k,1\}$. Let $\gamma=(k,m)$  Here's the answer from the textbook: Let $\sigma*k=1$ for some $k \neq 1$. Then as $m\geq 3$, choose an $m$ not an element of $\{k,1\}$. Now let $\gamma=(k,m)$. This gives $\gamma*\sigma*k=\gamma*(1)=1$ but $\sigma*\gamma*k=\sigma*m \neq 1$, since if $\sigma*m=1=\sigma*k$, then $m=k$, as $\sigma$ is one-to-one contrary to the assumption. I guess I'm just not understanding the steps to their proof. Can anybody make sense of this to someone new to proofs? I mostly don't understand how $\sigma*\gamma*k=\sigma*m=1$

Find the center of the symmetry group $S_n$.   Attempt:  By definition, the center is $Z(S_n) = \{ a \in S_n : ag = ga \forall\  g \in S_n\}$. Then we know the identity $e$ is in $S_n$ since there is always the trivial permutation. Suppose $a$ is in $S_n$, but not equal to identity. Now we can imagine the permutation as bijective function that maps from $\{1,2,\dotsc,n\}$ to $\{1,2,\dotsc,n\}$.  So suppose $p$ is a permutation map. Then $p$ maps from a location $i$ to a location $j$. Take $p(i) = j$ where $i\neq j$. Let $k$ be in $\{1,2,\dotsc,n\}$, where $k$, $i$ and $j$ are all different elements. The cycle $r = (jk)$, then we will see if this commutes.  $rp(i) = rj$    Can someone please help me, I am stuck?  Thank you.


Essentially want I want to do is trade from Pokemon Red/Gold and with Pokemon x. Is there any cord/equipment (specifically) out there that allows me to trade Pokemon from games playable on my Gameboy Advance SP with games on my 3DS?   I also have a DS floating around (and Platinum game) somewhere that I could use as a middle-man, but I'd rather not if possible.  Any technique to do this would be great.

I know that you can trade Pokemon between games of the same generation (Gold/Silver, Ruby/Sapphire) and even trade between 1st gen and 2nd gen. However, I haven't been able to find a way to trade Pokemon so that I can play with my 1st generation Pokemon in HeartGold, for instance. If it is possible, how many steps would it take and what equipment would I need?


Almost every creature you see, besides the elephants, walk on two legs, like me.

I'm confused by the use of plural and singular when Every is use. Which of the following sentences is correct?    Every business has its own unique set of challenges, resulting in a different approach even if they have the same goals. Every businesses have their own unique set of challenges, resulting in different approaches even if they have the same goals.


I would like to ask if I should move my Android/iOS project folders to SD card. Assume that I work with them every working day.  Same question for Dropbox and Google Drive folders, but I'm much less likely to use anything there compare to the Android/iOS project folders above.  Thank you

I'm planning to buy a 64GB SD card to supplement the storage on my MacBook Air 128GB (early 2015)  I wanted to know if I can move my Xcode and android studio to it as both have them take a significant part of the memory.  If this can happen, I wanted to know how can I move these two to the SD card. I'm fairly new to macOS and have no idea how to do this.


I have a simple monkey model, that is completely black but has white, emissive eyes, like that:  Then, in compositor, I have this setup:  Clearly, you can see the preview is not showing any glare effect. I think, that I'm missing something there, but for the sake of me I can't figure out what.

I am wanting to animate a row of LED lights. I have separated the LED lights from the rest of my object with the pass index/ID mask functions; currently all of my LED lights are on pass index #1.  What I want is to have a minor halo effect around the lights, but only when they are active. Currently, when I add a halo effect to my pass index #1, all of the LED lights have a halo effect regardless if the LEDs are emitting light. All LEDs are diffuse and emission shaders, so I can animate by controlling the mix amount between diffuse and emission.   Is there any simple way to have the halo effect created through recognizing light emission values, or will I have to just animate each LED as its own layer of compositing?


I have a server which runs Debian 8. I wish to install various security updates however, prior doing so, i would like to know if any of the updates will restart a running service.    Is there a way (command - script) which can help me found out if a package will restart any process-daemon?  I would like to pinpoint here that i am interested if an update will automatically restart a service and not if a service requires a reboot after the update.

I have 4 servers with Debian Wheezy OS. I have Apticron installed that informs me about updates. Debian updates are realized so often that when I finish to update the last of 4 servers I get new email about new updates on the first server. I try to update all servers when I get a notification but I never know if there is a need to reboot the servers. I have read that if the directory "/var/run" contains file "reboot-required" I have to reboot the server. But I never have seen this file in "/var/run". How can I know when reboot is required? I don't want reboot my servers every time when I install new updates if it's not needed.  I understand that if I update PHP or MySQL, etc I don't need to reboot the server but updates usually contain many "lib...".  Below are 9 updates (I have received this week).  krb5-locales 1.10.1+dfsg-5+deb7u3 libdbus-1-3 1.6.8-1+deb7u6 libgssapi-krb5-2 1.10.1+dfsg-5+deb7u3 libk5crypto3 1.10.1+dfsg-5+deb7u3 libkrb5-3 1.10.1+dfsg-5+deb7u3 libkrb5support0 1.10.1+dfsg-5+deb7u3 libruby1.8 1.8.7.358-7.1+deb7u2 libxml2 2.8.0+dfsg1-7+wheezy3 ruby1.8 1.8.7.358-7.1+deb7u2   I have no idea what is "libkrb,libgssapi", etc. How can I detect if reboot is needed? Please do not suggest to install UnattendedUpgrades to let the servers update automatically because this can cause websites going offline if something updates not correct.


I have noticed my system is not using any swap.    system got unresponsive when RAM got full swapon --show returns nil  /etc/fstab has nothing about swap in it   I am utterly confused by the myriad of different ways to enable swap which I read about. Do I really need to define a swap file, rather than only point the system at a swap partition?   I have a partition of the right size formatted as linux-swap. What is the series of steps to be taken for (perpetually) enabling it in my OS?  Ubuntu 16.04

I did not create a swap partition during Ubuntu installation.  Later, I freed up some space and made a swap partition.  Now after each boot up, I am manually opening gparted to right-click the swap partition to turn on the 'swapon' option.  How can I automatically enable the swap partition at boot?  Also, if I had not created the swap partition, what are my other options?


I've written a simple program to check if the input is the letter O or not.  For some reason, even when I type the letter O, the program outputs that the input is not the letter O.  I have used the Eclipse debugger to ensure that the input variable actually equals "O".  import java.util.Scanner;  public class scannerTest {  public static void main(String[] args) {     Scanner scan = new Scanner(System.in);     System.out.println("Give your input. I will tell you if your input is 'O' or not");     String input = scan.next();     if (input == "O"){         System.out.println("Your input was 'O'");         }     else {         System.out.println("Your input was not 'O'");     } }  }

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


I have been offered an opportunity for a part time PhD in Computer Science. I have had brief conversation with the person that would be my advisor. He has suggested that I start to think of a topic/proposal.  I literally have no idea where to start, what level of detail I should be looking at for a proposal?  I have read a couple of the articles on this site like:    These all offer great advise. Maybe I'm missing something but I am starting to feel a bit overwhelmed already!  One idea I have had is modelling student success based on different factors like: home environment, past student success, etc.  All I keep thinking of is the advisor said "It needs to be something new".  I guess any advise on creating a research proposal, picking a topic, where to begin... would be great.

In many countries an application for a PhD position includes a written research proposal, so my questions is what are some advises/strategies to come up with a good topic/idea for a PhD research proposal and how can one assess the quality/fruitfulness of an idea? As an undergraduate student one just doesn't have the experience to foresee which ideas might have promising research results and which probably won't have. (And I doubt that potential supervisors have the time to comment on every idea of every potential applicant in cases where it is possible to establish some kind of contact before the actual application.)


I have the following code:   def new():      test = [ {} ] *2     test[0]['a'] = 6     return test   First, I generate a list with 2 empty dictionaries Then I ONLY input the value 6 into key 'a' in the FIRST dictionary However, when I return the value test, it showed that test = [{'a':6, 'a':6}  How is that possible?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I have installed Oracle VirtualBox on my Windows 10 machine. As a guest OS I installed Ubuntu 16.04.04.  When I open the terminal on Ubuntu and run a command like:  sudo apt-get update   I get the following errors:  sudo: unable to change to root gid: Operation not permitted sudo: unable to initialize policy plugin   Actually I can't execute any sudo command. Any one knows how to diagnose/solve the problem?  I should metion that I am logged in using the guest account. So when I enter groups I get   guest-rqj3wa

When I login as guest I am unable to execute any command with sudo.  E.g.:  sudo ps   returns:  sudo: unable to change to sudoers gid: Operation not permitted   How can I fix this?


While reviewing close votes on SO, I was presented with this question:    which - in my opinion - is much too broad (the OP added no less than three additional sub-questions).  The voting system told me that I hadn't paid attention and this question should be left open. I disagree, and I'd like to support the proposal of a "disagree with this" button or similar (as was already suggested in   I don't mind the system telling me when I made a mistake - as long as I can tell the system when it is making a mistake, as well :-)

When approving a post that system thinks should not have you are presented with something along the lines of  This post has severe quality issues. It is abusive nonsense, noise, spam, blatantly off-topic or otherwise irredeemable - readers will find it offensive or repulsive rather than helpful. You should delete or recommend deletion when reviewing such posts. Don't worry, we've already handled this post appropriately - but please take a minute to look it over closely, keeping in mind the guidance shown above.  With a "I understand" button, what about if you disagree with that assertion? Is there a way to indicate that? If there isn't perhaps one should be added so that data can be collected to improve the system. For example: While reviewing the low quality posts queue I got the following answer from  to to the question   Try  (I'm a developer). It does exactly what you're looking for, free of charge.  Which I approved and the system responded that I should have recommended deletion. From what it looks like to me the OP is asking a question about adding basic username/password authentication for an Amazon s3 hosted website and the answer is mentioning a free product/service that does what the user wants. It is true that the user answering is affiliated (they posted a disclaimer) with the product but from what I understand that is .


My computer rebooted when I wasn't home and I lost several very important notepad files. Is there any way to recover them? Anything?

I was running NotePad and Chrome when my computer suddenly shuts down.  After reboot, chrome was able to "restore" itself such that I didn't lose any data.  However, how do we "restore" notepad.exe?


Construct a smallest possible relation on the set {a, b, c, d} that is  irreflexive, symmetric, and transitive. I thought that the relation would be an empty set, R is symmetric because (a,b) can never belong to it and so the conditional statement is always true. R is transitive because (a,b) and (b,c) can never belong to it and so the conditional statement is always true. do you think that there is anything wrong with my assumption?

An equivalence relation is defined by three properties: reflexivity, symmetry and transitivity.  Doesn't symmetry and transitivity implies reflexivity? Consider the following argument.  For any $a$ and $b$, $a R b$ implies $b R a$ by symmetry. Using transitivity, we have $a R a$.  Source: Exercise 8.46, P195 of Mathematical Proofs, 2nd (not 3rd) ed. by Chartrand et al


I'm in the process of figuring out blender (on what could be considered my 3rd project I guess), and while browsing tutorials and youtube videos about blender, I've come across the topic of PBR materials, and have found it intriguing. I've found that using these materials makes my renders look a whole lot better than if I just slap a flat texture on the objects, but I'm a student and don't want to be spending money on this hobby just yet, which has run me into the issue that there aren't a whole lot of these materials out there that aren't reserved for some payed service. Do any of you know of any material libraries out there with PBR materials for free? So far I've been using the free materials on poliigon, and came across freepbr.com, but I can't figure out how to download any of the textures/maps from the latter of those two.  Any help is appreciated! Thanks, Ethan

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


Sorry this is a very small segment of code:  var arr = [2,4,6,8]; var obj = {}; for (var i in arr) {     obj[arr[i]] = arr[i] * 2; }   What I expect it to do is output the values of arr in an object, and return those values doubled.  My does that but also includes this:  'function () {\r\n  var result = [];\r\n  for (var property in this)\r\n    result.push(property);\r\n  return result;\r\n}': NaN   Can anyone explain to me why this happens?  Thank you.

I've been told not to use for...in with arrays in JavaScript. Why not?


I'm working on a macro to help me inserting figures into my document with configurable placement. I'm using the pgfkeys package for parsing key=value parameters passed to that macro, one of them being the placement parameter:  \documentclass{article}  \usepackage{float} \usepackage[demo]{graphicx} \usepackage{lipsum} \usepackage{pgfkeys}  \pgfkeys{     /fig/.is family, /fig,     default/.style = {         pos =,     },     pos/.estore in = \figPos, }  \newcommand\mymacro[2][]{     \pgfkeys{/fig, default, #1}     {\em Placement parameter is: \figPos}     \begin{figure}[\figPos]         \includegraphics{#2}     \end{figure} }  \begin{document}  \section{Working as expected}  \lipsum[1]  \begin{figure}[t] \includegraphics{image.jpg} \end{figure}%  \lipsum[2]  \lipsum[3]  \section{Not working as expected}  \lipsum[1]  \mymacro[pos=t]{image.jpg}  \lipsum[2]  \lipsum[3]  \end{document}   When using the figure environment directly, the image gets positioned as expected, i.e. at the top of the page. However, when using the macro, the image gets included somewhere near the end of the document instead of close to its definition -- as though I had supplied an invalid placement parameter.  Any ideas and/or workarounds?

Why is the following minimal example not working?  I.e., what do I need to do, in order to define the float placement specifier of a figure within a macro? (I know that I should use \newcommand, but in the "full" example the error is part of an involved "superfigure" command. \newcommand is not working too btw.)  \documentclass{scrreprt} \usepackage{blindtext}  \def\PosNotWorking{h} \def\FramboxNotWorking{5cm} \def\CaptionWorking{Caption is working.}  \begin{document}  \Blindtext[1]  \begin{figure}[\PosNotWorking]   \centering     \framebox[5cm]{My special figure. (Pos: \PosNotWorking)}             \caption{\CaptionWorking} \end{figure}  \Blindtext[1]  \end{document}   If I compile this, the figure is at the top (default behaviour). If I enter \figure[h] instead of \figure[\PosNotWorking], the figure is of course between the two paragraphs.


var position = prompt("position:"); var manager = ["John", "Alex", "Joe"]; var admin = ["Texas", "Jesus", "Rick"]; var tech = ["Nexus", "Thomas", "Fred"] if (position == manager) { alert("manager")}  if (position == admin) {   alert("admin")}  if (position == tech) {   alert("tech") }  else {   alert("Incorrect position")   }  I would like to ask how it is possible to this program work. When I will enter in prompt John I would like to get alert manager when I will enter in prompt Rick I would like to have alert tech etc...   And also if I will enter something what is unknown random value it will get me Incorrect position.   Also I would like to ask if there is way when I will enter in prompt for example jOHN or john it will work. I am total beginner in JS and coding.

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


I am writing a python script and I want this script to write some value to an environment variable which does not exist before the running of this script. The OS which I am running is Ubuntu. So ideally, after execution of the script, I should be able to display the environment variable using the echo command on the terminal. By that I mean the terminal behaviour should be as such:  > echo $NEW_VAR environmentvarvalue   I want to be able to access this environment variable in a different python script as well. So the following code:  import os output = "The value of NEW_VAR is " + os.environ.get('NEW_VAR') print output   when run after running the initial script, should produce the following output when executed:  The value of NEW_VAR is environmentvarvalue   I have tried the following code in my initial script after a bit of research about this:  import os os.environ['NEW_VAR'] = 'environmentvarvalue'   but the environment variable gets saved only for the scope of the initial scrpt, and when I run the echo command on the terminal after execution of the script, the behaviour is the same as when the variable does not exist. Is there something wrong with my code? Or is there a better way of assigning an environment variable through python? I know that I can probably run the export command from the subprocess python module, but this does not seem like the right way to solve this problem.

I'm trying to write a shell script that, when run, will set some environment variables that will stay set in the caller's shell.  setenv FOO foo   in csh/tcsh, or  export FOO=foo   in sh/bash only set it during the script's execution.  I already know that   source myscript   will run the commands of the script rather than launching a new shell, and that can result in setting the "caller's" environment.  But here's the rub:  I want this script to be callable from either bash or csh.  In other words, I want users of either shell to be able to run my script and have their shell's environment changed.  So 'source' won't work for me, since a user running csh can't source a bash script, and a user running bash can't source a csh script.  Is there any reasonable solution that doesn't involve having to write and maintain TWO versions on the script?


In clash of clans I'm in a clan that does lots of wars. But the leader tried putting me in the war but can't because I have a red shield (it shows on the far left on a name tag).   How would I get a green shield?

I am currently in a clan with three members. When we tried to initiate a clan war it said we had insufficient clan requirements. Does anyone know what the full requirements are? Is there a minimum clan member requirement?


Consider the series $$\sum_{n=1}^{\infty} \frac{\sqrt{n+1}-\sqrt{n}}{n}$$ Does this series converge or diverge?   I tried all the tests like ratio test, Raabe's test, logarithmic test, comparison test but in vain. In ratio test I got the limit as $1$, so can't do anything with that. Can anybody give some hints?  Thank you!

Does this series converge or diverge?  $$\sum_{n=1}^\infty\frac{\sqrt{n+1}-\sqrt{n}}{n}$$  I tried the comparsion test with $\sum_{n=1}^\infty$ $1 \over n$ but this does not help.  I also tried to simplify the series to $\sum_{n=1}^\infty \frac{1}{n (\sqrt{n+1}+\sqrt{n}{}{}{})}$ but this become harder.


I need to prove that the interval $(a,b)$ and the set of Real numbers share the same cardinality.    I understand that I need to find a bijection between the two sets. I have been hinted to use something like $(0,1)$ or $(-1,1)$ to find a bijection then extend it to all reals. I need advice on how to set up the actual proof. Trigonometric functions are not to be used in this proof.

I want to prove that every open interval has the same cardinality of $\Bbb R$.  The question is:  Is it enough to prove that any open interval is uncountable? If I prove it, can I say that this interval has the same cardinality of reals?  I know that I can get a bijection using the tangent function, but I am not allowed to use trigonometric functions.  I've proved that |$(a,b)$|=|$(0,1)$| so I may prove that |$(0,1)$|=|$\Bbb R$| but I did not find the bijection without using trigonometric functions.


Is there a way to make the Stock Widget in iOS's Notification Center to display percentage change instead of price change? Any Cydia tweak?  In the Stocks.app you can switch between those and market cap by pressing the price change tile on the right.

Can I show the percentage change instead of price change in the new stocks app?


I am following a proof of an RSA algorithm and the proof states the following:  $p_1$ and $p_2$ are distinct primes, $a \equiv b \pmod{p_1}$ and $a \equiv b \pmod{p_2} \Rightarrow a \equiv b \pmod{p_1\times p_2}$. Let's call that FACT X.  can someone give me a proof for this. i have no formal mathematical training so a detailed proof will be much appreciated.

$p_1, p_2$ are distinct prime numbers  I have just observed this pattern when solving  problem. Is there a simple way to prove/disprove it ?


I made a selection of faces on an object emissive. They radiate orange light. However, the faces themselves are still white. How can I make sure they are the same color as the light they emit?

I am trying to make a computer monitor. This means I have to have an image texture for the screen. My image texture is currently connected to an Emission BSDF shader. Unfortunately, when the emission is bright enough to emit light, the image is white-washed. I tried adding a Brightness/contrast node to the image before pushing it into the Emission BSDF, but it seems to directly counter the Emission's strength.  The desired light level   The desired image brightness


EDIT Thanks to user , this issue boiled down to Templates, and my understanding of how they work.  I had to move function implementations into the class header, otherwise they would not be compiled for some arbitrary type.  See     I'm writing a template class, Tensor, which can be ininitalised to hold elements of type T, whose constructors takes some arguments.  I've found that if I try to create an object of class Tensor in any other file, it fails with undefined reference.  I made sure that I'm including the header correctly, and even created a function unrelated to the class called test_boi() which can be called successfully by other files.  I won't go into the details of my testing setup, but I have a MWE with 3 files: tensor.cpp, tensor.h, and main.cpp.  In tensor.cpp I have a main() which works when uncommented.  It is identical to the one in main.cpp, which fails with the undefined reference error.  For building (with CMake), I make a library using tensor.h and tensor.cpp and add it to my executable.  I think this might be my problem, but I'm not sure what I'm doing wrong.  Making libraries is something I've just started doing, and there's a deluge of info out there.  The fact that I am able to call test_boi() from Main.exe (when I don't create objects) tells me that tensor.cpp has been compiled, and is accessible by Main.exe.  The fact that I can create these objects when I put main() in tensor.cpp tells me that there isn't something broken in my classes.  "Undefined reference" stackoverflow posts are rampant, so I haven't been able to find anything that fits my particular issue.  Relevant portion of my CMake script  add_library (libTensor tensor.h tensor.cpp)  add_executable(Main.exe test_main.cpp) target_link_libraries(Main.exe libTensor)  #add_executable (Tensor.exe tensor.cpp) #target_link_libraries (Tensor.exe Tensor)   My Class definition (tensor.h)  #ifndef TENSOR_H #define TENSOR_H #include <vector>  template<typename T> class MyClass {   int width, height;  public:   MyClass(int n, int m)   {     height = n;     width = m;   };   MyClass(int n, int m, std::vector<T> elems); };  int test_bois(); #endif   My function implementations (tensor.cpp) ```  #include <iostream> #include "tensor.h"  template<typename T> Tensor<T>::Tensor(int n, int m) {   //  shape = (height, width);   height = n;   width = m; }  template<typename T> Tensor<T>::Tensor(int n, int m, std::vector<T> elems) {   //  shape = (height, width);   height = n + 100;   width = m + 100; }  int test_bois() {   return 42; }  // int main() // { //   std::vector<int> elems(10); //   int height = 2; //   int width = 2; //   Tensor<int> *my_obj_zero = new Tensor<int>(height, width); //   Tensor<int> *my_obj_one= new Tensor<int>(height, width, elems); //   std::cout << my_obj_zero->shape() << std::endl; //   std::cout << my_obj_one->shape() << std::endl; //   std::cout << "Hello World!!" << std::endl; //   return 0; // }   main.cpp  #include <iostream> #include "tensor.h"  int main() {   std::cout << test_boi() << std::endl;    // this block commented out to get successful run   std::vector<int> elems(10);   int height = 2;   int width = 2;   Tensor<int> *my_obj_zero = new Tensor<int>(height, width);   Tensor<int> *my_obj_one= new Tensor<int>(height, width, elems);   std::cout << my_obj_zero->shape() << std::endl;   std::cout << my_obj_one->shape() << std::endl;   std::cout << "Hello World!!" << std::endl;    return 0; }

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


we read that if $(\Omega, \mathcal{F}, \mathcal{P})$ is a probability space and $X:\Omega\to\mathbb{R}$ is a random variable with mean and variance, then $$\min\limits_{c\in\mathbb{R}}\mathbb{E}((X - c)^{2}) = \mathbb{E}((X-\mathbb{E}(X))^2).$$ I.e., the expected value $c=\mathbb{E}(X)$ minimizes $\mathbb{E}((X - c)^{2}).$ My question is how to prove it?

According to the Page 87 in Kruschke: Doing Bayesian Data Analysis, the author says that the mean of a distribution is a value that minimizes the variance of a probability distribution, for example, a normal distribution. The following is what is mentioned in the page:  It turns out that the value of $ M $ that minimizes $ ∫dx p(x)(x−M)^2$ is $E[X] $. In other words, the mean of the distribution is the value that minimizes the expected squared deviation. In this way, the mean is a central tendency of the distribution.  I have read the paragraph and kind of understood what the author is trying to say but I wonder how this can be written mathematically using the above equation or any other ways.


I have the following in a script:  #!/usr/bin/env bash  ... for i in {1..$N}    <loop content>   The above doesn't work and is only executed once where i has the value {1..5}  (if 5 was provided as argument).  If I replace the above with:  for i in $(seq 1 1 $N)   .. then things work as expected. Why is that?

In response to a comment of mine to  on SF the OP asserts that the   for i in {1..$NUM}   expands correctly in bash. I have access to bash 4.0.33 (Ubuntu), 3.2.25 (Centos) and 3.00.16(1) (solaris 10). None of these will expand the {1..$NUM}.   Does anyone know which versions of bash do the expansion? If it's not bash what is it ? I know zsh will do the expansion but in the OP's script the shebang should remove the possibility of an alias ?


I'm trying to load & create all classes that implements specific  interface in java using reflection?  Say i have :  package Test;  interface foo {} class one implements foo { } class two implements foo { }   how it can be done?  can u assist?

Some time ago, I came across a piece of code, that used some piece of standard Java functionality to locate the classes that implemented a given interface. I know the functions were hidden in some non-logical place, but they could be used for other classes as the package name implied. Back then I did not need it, so I forgot about it, but now I do, and I can't seem to find the functions again. Where can these functions be found?  Edit: I'm not looking for any IDE functions or anything, but rather something that can be executed within the Java application.


I am a python beginner, and I am working on an interactive shell/terminal. I want to clear screen interactively with input. Would someone help me please, figure out a cross-platform solution.

Like most Python developers, I typically keep a console window open with the Python interpreter running to test commands, dir() stuff, help() stuff, etc.  Like any console, after a while the visible backlog of past commands and prints gets to be cluttered, and sometimes confusing when re-running the same command several times.  I'm wondering if, and how, to clear the Python interpreter console.  I've heard about doing a system call and either calling cls on Windows or clear on Linux, but I was hoping there was something I could command the interpreter itself to do.  Note: I'm running on Windows, so Ctrl+L doesn't work.


Desgining the UI for a center stack (100% touchscreen), still in the wireframe stages. However, when mocking up the home screen, it dawned on me I don't know much about UX (I do mostly backend work, and am slowly breaching my way to design). So, that leaves me two options:   Blindly follow the OEM's design just because it's the OEM's design, while changing simple things like icons and backgrounds. Create a new design from the ground up, while taking into account hig (if any exist for this sector).   I would like to go with #2, to set my UI apart from the rest, but still be easy to use. I have a few guidelines in mind, but want a 'sanity check' and also if any documentation exists on this somewhere then also have that as a resource (I'm still googling for this at the time of this writing).  Here is what I have so far:   Anything potentially used by the driver while driving should be easily identifiable at a glance, and easy to use/change (i.e. BIG BUTTONS with familar pictures Settings/Options most likely used should be not be more than 1-2 levels deep, if at all possible. Important/Relevant Information should be displayed on every screen such as the clock, important diagnostic/service information such as battery charge for electric vehicles, etc. Fast response time, meaning no (or very little) cheesy screen transitions. My theory is that on this platform it wastes time, and the longer it takes to refresh the screen with new content, the longer the driver's eyes are off the road (potentially). Not a big deal at a red light, but obviously almost everyone has changed the heat or radio on a freeway, where taking one's eyes off the road for 4 seconds @ 60mph is equivalent to traveling the length of an entire American Football field blind.   I'm sure I have more, but those are the high points of course. Any more info is welcomed.  Update    To be crystal clear, I am asking what (if any) UX guidelines exist for the automotive platform, or what one should keep in mind. This is not a 'port' of an existing application to a platform that has publicly established hig. user1757436's link provided valuable documentation on some of the research done in this domain.

My new project is to port an iOS app to Android platform. Before get started, I'm quite confused on whether I should follow google's guideline since some big titles on Android platform still keep the same look as iOS version. Style here means the entire design of the app, such as app navigation, theme, and layout.   Please help if you have any suggestions!


Can you please correct this sentence. I am bit confused about this sentence. I think its not a correct sentence.

Which one is correct?         I go to school by foot.   I go to school on foot.       Are there instances when the expression by foot is preferred?    My last question is the following:   Why is the singular noun, foot, used?     If a person goes to school by bus/train/car they are using only one means of transport, they are travelling in one car not two. But people use both feet for walking, so why would the following expressions be ungrammatical?         I go to school by feet     I go to school on feet      I read the answers on this question  but they did not convince me.


Prove that there are infinitely many  integers $n$ such that $\frac {2^{6n}-4}{6n-1}$ is equal to an integer  I am struggling with this qustion. Could you walk me through it?

I have seen the past threads but I think I have another proof, though am not entirely convinced.  Suppose there are only finitely many primes $p_1, ..., p_n$ of the form $6k-1$ and then consider the number  $N = (p_1.p_2. ... .p_n)^2 - 1$  If all of the primes dividing N are of the form $6k+1$ then $N$ leaves remainder $1$ upon division by $6$. However, the RHS has remainder $1-1 = 0$ or $-1-1 = -2$ upon division by $6$, depending on whether $n$ is even or odd.  Therefore there must be at least one prime of the form $6k-1$ dividing $N$, and thus some $p_j$ divides N, and so divides $(p_1.p_2. ... .p_n)^2 - N$ which is $1$, a contradiction.  Apologies for this question if it appears unnecessary I'm just beginning number theory and trying to get to grips with it.


Suppose $x\in \mathbb{Q}$ such that $x^{2}=6$. Since  $x\in \mathbb{Q}$, there exists $m,n \in \mathbb{Z} $ where either $m$ or $n$ is odd such that $x=\frac{m}{n}$.  $\implies$ $x^2=(\frac{m}{n})^2=\frac{m^2}{n^2}=6$  $\implies$ $m^2=6n^2$, so $m^2$ is even. Hence, $m$ is even.  Since $m$ is even, $m=2k, k\in \mathbb{Z}$.  Then, $m^2=(2k)^2=4k^2=6n^2$  $\implies$ $n^2$ is even, so $n$ is even. But one of $m$ or $n$ must be odd, so $x\notin \mathbb{Q}$.  Therefore, $\sqrt{6}$ is irrational.  Does everything look alright here?

Suppose $\sqrt6 = \frac pq$ where $p$ and $q$ have no common factors.  $$6 = \frac {p^2}{q^2}$$  $$6p^2 = q^2$$  So $q^2$ and therefore $q$ is divisible by $6$.   $$p^2 = \frac {q^2}{6}$$  So $p^2$ and therefore $p$ is divisible by $6$.   S0, $p$ and $q$ have a common factor $6$. Contradiction.  Therefore $\sqrt6$ is irrational.  Does the proof work?


Consider this simple MWE:  \documentclass{article} \usepackage[a6paper,showframe]{geometry} \setlength{\parindent}{0pt} \begin{document} Hello world \end{document}     This is all fine. But if I start the document with an equation, then there is some added vertical space. Does anyone know what is causing this? I'm guessing there is some \vskip command in a .cls file where this is being defined?  \documentclass{article} \usepackage[a6paper,showframe]{geometry} \usepackage[fleqn]{mathtools} \setlength{\mathindent}{0pt} \begin{document} \begin{equation*} \text{Hello world} \end{equation*} \end{document}

I need every amsmath equation to place at the top of the page. So I use \noindent to do that. Everything is fine except equation+split environment. Than formula is placed a bit higher (by \vskip-\lineskiplimit (it's -3pt) from asmmath.sty \@display@init macro). align+split is ok. The glue is discardable item but it's in a box so it's not discarded.  ....\glue(\topskip) 0.0 ....\hbox(21.00012+16.0001)x430.00462, direction TLT .....\vbox(21.00012+16.0001)x430.00462, direction TLT ......\glue -3.0 ......\glue 0.0   MWE:  \documentclass{article} \usepackage[showframe,paperwidth=10cm,paperheight=5cm]{geometry} \usepackage{amsmath}  \begin{document}  \noindent \[ \begin{split} \left(a^{B^{B^{B}}}\right) \\ bb \end{split} \]  \clearpage \noindent \begin{align} \begin{split} \left(a^{B^{B^{B}}}\right) \\ bb \end{split} \end{align}  \end{document}   Result:   Questions:   Is there a way to test am I on the top of page? Then I could fix that \vskip. I tried leaders but its very tricky.  Is there an other way to place formulas forcing \topskip?


Given the logical block number from these log lines in /var/log/messages, is there a way to determine what file was affected?  ...Buffer I/O error on device sdd1, logical block 203953715 ...lost page write due to I/O error on sdd1

I have an ext4 filesystem that recently developed some bad sectors.  Running fsck.ext4 -c finds and remembers the bad blocks.  How can I find which files (if any) included these bad blocks so I can restore them from backups?


For positive integers Numbers  $a, b, c $ prove that  $$\frac{1+a^{2}}{1+b+c^{2}} +\frac{1+b^{2}}{1+c+a^{2}} +\frac{1+c^{2}}{1+a+b^{2}} \geq  2$$ This inequality above take long time to prove it and still couldn't complete it.  How I can prove this inequality?  Any hint will help. Thanks


I'm just wondering how these kinds of graphics are created, i.e. the white lines that twist and turn across the page. I see them all the time and was just wondering if there is a way to create them in Illustrator using the Blend tool or wrapping a grid along a path? I'm not sure. Thanks!

I've been trying to create an abstract pink background similar to this one:    I can't seem to find any tutorial on how to do it. How are those wavy looking lines created?  Thanks.


I tried running a small mp4 video file in Videos on Ubuntu 20.10 and got a message that I needed a certain codec. I followed a link in that message that didn't work (it didn't go anywhere). So I searched in AskUbuntu and found a similar problem that required me to run 'sudo apt-get install ubuntu-restricted-extras' in terminal which I did. It finally got to this:  Now I can't do anything. I've tried pressing enter, esc, clicking 'ok' - nothing can get me past this graphic. Terminal is stuck until I can finish installing this software so can someone suggest what I need to do next? Regards, Alan

I tried playing videos in movie player but only the audio could be heard. I tried playing the video with dragon player but here also only the audio could be heard.  A message box appeared showing the following message:     Python (v2.7) requires to install plugins to play media files of the following type: H.264 decoder   I tried installing the plugin but it couldn't be installed. It isn't available in the software center too. How can I get this plugin?


are the tense of the verbs true in each sentence?  1-I think Jimmy did his duty as other police officers do.(simple past+simple present is true?)   2-I think he did the right thing because he is a police officer (simple past+present is true?)

I'm describing a situation that happened in the past. To explain it, I want to use a description that is both true now and true when the situation happened.  Specifically, I want something like:     She touched me where my neck met my collarbone.   Since my neck is still attached to my collarbone (thankfully), I'm wondering if I shouldn't use the present tense here instead:     She touched me where my neck meets my collarbone.   Which is preferable, and why?


I bought this bike like an hour and a half ago for $60 and I cant find the exact model. I am not really a bike guy so I'd appreciate some help :)

We often get questions on bicycles.stackexchange about identifying a bicycles manufacturer, model, make, and year.  Often these questions are downvoted or closed -- usually with a comment attached to them that it's not necessary to know the exact model/make/year of a bicycle if you want to fix, repair, or ride your bike. Why should owners not care about the model/make/year of their bicycle? Especially when it comes to less expensive bikes (aka BSOs) and BMX bicycles? This is intended as a canonical question that we can point closed questions to. Also see      (generally not helpful for identifying a brand/model)


I have Fedora 24 installed on my PC. I am also running a Docker container for development. Each time I try to access https://twitter.com I can't and I get this error:     This site can’t be reached      This site on the company, organization or school intranet has the same   URL as an external website.       Try contacting your system administrator. ERR_ICANN_NAME_COLLISION   After some research I am not able to find a solution. So I followed some steps in order to help you help me back:   Ping twitter.com from terminal:  $ ping twitter.com PING twitter.com.dev (127.0.53.53) 56(84) bytes of data. 64 bytes from 127.0.53.53 (127.0.53.53): icmp_seq=1 ttl=64 time=0.064 ms 64 bytes from 127.0.53.53 (127.0.53.53): icmp_seq=2 ttl=64 time=0.252 ms 64 bytes from 127.0.53.53 (127.0.53.53): icmp_seq=3 ttl=64 time=0.069 ms    Wait a minute? Response from twitter.com.dev and IP 127.0.53.53 what that hell? How can this be possible? Ok, let's try to figure it out:   Check /etc/hosts in the Fedora Workstation:  $ cat /etc/hosts 127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6 #172.19.0.2 rperez.dev => This is a test using Docker container internal IP address #192.168.1.66 rperez.dev => This is a test using Fedora Workstation IP address 127.0.0.1   rperez.dev => This is another test using "localhost" which work as well    No luck, nothing is pointing to twitter.com.dev so nothing is redirecting me. Keep going:   Check /etc/hosts on the Docker container:  # cat /etc/hosts  127.0.0.1   localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 192.168.1.66    dockerhost 172.19.0.2  e59b9797ae06    No luck, nothing is pointing to twitter.com.dev. At this point I am out of ideas on what to check or what to fix.   The funny part is that I can access to Internet and navigate to any other site like Gmail, Microsoft, Google, News sites and so on but Twitter.   Other people at office are able to access Twitter. The difference? They are using DHCP I am not, I have setup my IP to be static.  $ cat /etc/sysconfig/network-scripts/ifcfg-enp0s31f6  HWADDR=C8:5B:76:1A:8E:55 TYPE=Ethernet BOOTPROTO=none DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=no IPV6_AUTOCONF=no IPV6_DEFROUTE=no IPV6_FAILURE_FATAL=no IPV6_ADDR_GEN_MODE=stable-privacy NAME=enp0s31f6 UUID=0af812a3-ac8e-32a0-887d-10884872d6c7 ONBOOT=yes DNS1=8.8.8.8 DNS2=8.8.4.4 IPADDR=192.168.1.66 PREFIX=24 GATEWAY=192.168.1.1 IPV6_PEERDNS=no IPV6_PEERROUTES=no   Any advice? If you need anything else from my side to give me an idea or clue, let me know and I will add it.  UPDATE  I am running the test above from work but I have tried from home and I got the same issue I believe is related to this"       I will wait and if that's the issue I will delete the post

I have servers named like server.prod.example.com, and I regularly log into them as server.prod.  Recently, these hostnames started resolving to 127.0.53.53.  It turns out that ICANN recently enabled the .prod TLD.  In addition, every request that goes to the .prod nameservers get resolved to 127.0.53.53 instead of coming back as NXDOMAIN, which would allow resolution to continue to work properly.  (I'm guessing the point behind this is to let people know that their stuff will break worse before those start resolving to something real.)  How can I avoid having to type in my domain name for every host like this?  Is this still biting you occasionally?  I couldn't find a list of new TLDs and when they were added, so I set one up myself:


I have written an @InvocableMethod, with an @IncovableVariable as such:  public class SimpleAccountLookup {      @InvocableMethod     public static List<Account> getAccountId(List<GetAccountActionRequest> requestDetails) {         System.debug(requestDetails);         List<Account> accounts = [SELECT Id FROM Account                               WHERE A_Custom_Field__c = :requestDetails.get(0).thatFieldValue                               LIMIT 10];         return accounts;     }      public class GetAccountActionRequest {         @InvocableVariable(required=true)         public String thatFieldValue;     }  }   Which all seems like legit Apex to me, and it saves and complies just fine.  However, when I go to my Flow builder, it isn't appearing in the list of Apex options as I would expect.    There are three other Apex methods in there (created by other developers) which are almost identical in composition... but mine is not there. I have waited a couple of hours - as I know sometimes these things take weirdly long in Salesforce (like Lightning Components appearing in the App builder), but it's just not there. Any one have any thoughts, tips, places to check, or other things I need to update?  This is just in a straight up sandbox, no managed package, domain, namespace.

I am trying to use following apex class with invocable method but its not showing in process builder.  global with sharing class SlackOpportunityPublisher {      private static final String slackURL = 'https://testsalesforceapps.slack.com/';      global class Oppty {         @InvocableVariable(label='Opportunity Name')         global String opptyName;         @InvocableVariable(label='Stage')         global String stage;     }      @InvocableMethod(label='Post to Slack')     global static void postToSlack(List<Oppty> oppties) {         Oppty o = oppties[0]; // If bulk, only post first to avoid overloading Slack channel         Map<String,Object> msg = new Map<String,Object>();         msg.put('text', 'The following opportunity has changed:\n' + o.opptyName + '\nNew Stage: *' + o.stage + '*');         msg.put('mrkdwn', true);         String body = JSON.serialize(msg);             System.enqueueJob(new QueueableSlackCall(slackURL, 'POST', body));     }      global class QueueableSlackCall implements System.Queueable, Database.AllowsCallouts {          private final String url;         private final String method;         private final String body;          global QueueableSlackCall(String url, String method, String body) {             this.url = url;             this.method = method;             this.body = body;         }          global void execute(System.QueueableContext ctx) {             HttpRequest req = new HttpRequest();             req.setEndpoint(url);             req.setMethod(method);             req.setBody(body);             Http http = new Http();             HttpResponse res = http.send(req);         }      }  }


How do I solve this:  $$\sum_{k=1}^{\infty}k(1-p)^{k-1}$$  I forgot how to do this, or the formula I need to use. Could not find it online for some reason.

How can I evaluate $$\sum_{n=1}^\infty\frac{2n}{3^{n+1}}$$? I know the answer thanks to , but I'm more concerned with how I can derive that answer. It cites tests to prove that it is convergent, but my class has never learned these before. So I feel that there must be a simpler method.  In general, how can I evaluate $$\sum_{n=0}^\infty (n+1)x^n?$$


In Ingress, if I hack a portal at 3pm, do I need to hack the next portal before 3pm the following day if I want to keep my current hacking streak (for the Sojourner badge) alive?

Does the 24 hours timer start:     when you hack a portal on a particular day     or     does it use the calendar days and check if you did hack a portal on a particular day   or     does it simply use a fixed international timezone to calculate the 24 hour cycle   or     does it use the agent's hacking cell's timezone to start it?   If it's the calendar days method than the explanation of the badge would be a little bit misguided because you could hack a portal on 00:01 on Saturday and then hack another one on 23:59 on Sunday and it would be practically two days between two hacks.  If it's based on the agent's last hack for a particular day then the explanation still would be problematic?  The third option would be a little bit unfair (or timezone racist) for the rest of the world.  The last option (the cell's timezone) would/could be both unfair for travellers and/or non-travellers.  Does anyone know any details about it?


I used to be able to download packages but recently I have been unable to do so for quite sometime now.  It gives the message:  get proxy host by name failed in tcp_connect()   I don't remember doing anything different except that I have moved from another location and I am using another broadband connect, but I am not sure if it is related to this problem.

I would like to use the function of TeXnicCenter 1.0, where is automatically downloads missing packages used. The problem is, that the repository it wants to download from does not exist anymore (the one on piotrkosoft.net).  How do I get TeXnicCenter to try with another repository?


The panchromatic band on Landsat 8 OLI sensor (band 8) covers a narrower portion of the spectrum than the corresponding band in Landsat 7 ETM+: 0.50 - 0.68 micrometers (L8 OLI) in contrast to 0.52 - 0.90 micrometers (L7 ETM+) (see complete tables ). Most remarkably, L8 OLI band 8 does not cover the near infrared, thus precluding pan sharpening in that portion of the spectrum and making up a significant difference with the L7 ETM+ panchromatic band. Why?  In this interesting , the author mentions the issue without being able to find the logic behind it, and citing the explanation given by Irons et al (2012) “The OLI panchromatic band, band 8, is also narrower relative to the ETM + panchromatic band to create greater contrast between vegetated areas and surfaces without vegetation in panchromatic images" as not clear or insufficient, and hinting to possible design glitches.  I am also left wondering about this and could not find a decent explanation anywhere. Does anyone in this forum know why?  Irons, J.R. et al. (2012) The next Landsat satellite: The Landsat Data Continuity Mission. Remote Sens. Envion.,122, 11-21. doi:10.1016/j.rse.2011.08.026

The Landsat ETM+ band-8 (Panchromatic) is identical to Landsat-8 OLI' Panchromatic band-8 in terms of spatial resolution i.e. 15 x 15m cell size. However, there is great difference in the wavelengths of both bands; ETM+ .52 - .90 and OLI 0.503 - 0.676 (micrometers).   See   Clearly, the wavelength placed for ETM+ steps over visible range. A visual comparison between both bands also indicates outcome of these differences.    Obviously, it is noticed that OLI' pan band is much handy in visual interpretation as well as suitable for pan-sharpening and image classification.  There might be some good aspects behind ETM+ panchromatic wavelength extending beyond visible range, I am interested to be enlightened about the same reason.


Related questions:      However I would like to address a specific case: feature requests. I  that was not well received. Feature requests questions . Now, if you get a ban, the  says:     All questions are expected to be useful to future visitors, too, so   put effort into writing with proper grammar and spelling, formatting   your post so it can be read easily, and providing as much detail as   possible about your problem and what you have already tried. Reading   your question out loud to yourself can help you understand what it   sounds like to others.   However, the automatic algorithm does not know about the quality of a post, it knows about votes, and for feature requests the votes can be very low even if the quality is ok. That puts in danger low rating users (but maybe experienced from other Stack websites) who want to propose an idea, and contribute to the website.  Is this is a relevant problem? How could be this situation prevented/mitigated?   Note: I know one "bad" question alone is not sufficient to get the warning. But since I got another question closed, I got a warning and for example now I am at risk even by posting this very question. Where I think I did my homework, but God knows who I can find out there in this dark night... :)  Edit: (This was the status of this question when justcool393 updated his answer)  Now I read about  However, why is the warning still so scarying?     Stack Exchange has automatic filters in place to ban questions from   accounts that have contributed many low-quality questions in the past   (Note: I am still readying details, but I urged to edit here to save this question from being closed)  (Then the question got closed so I moved to a new, more specific question)

appears to have been question banned because of two unpopular Meta suggestions. (He says so in )  Look at the two contributions that appear to have gotten him banned. Like those of many others, they may not be of perfect quality, but they are not actively harmful to the site, either. As it stands, you can get question blocked on Meta simply for asking questions that aren't popular with the Meta crowd.  Why does the team insist on keeping the question ban active on Meta?  Why can't real problem users be dealt with through manual moderator action? Don't tell me it's a problem of scale; as far as I can see, actually toxic users are very rare on Meta.  People will frequently complain that Meta actively discourages the expression of unpopular viewpoints and suggestions. With the threat of question bans in place, I find those complaints difficult to refute. I hate that.


Can anybody explain the physical interpretation of  $$\iiint (\nabla\cdot \vec E)~\mbox{d}V~=~\frac{Q}{\epsilon_0}?  $$   Also, how is the differential form of Gauss's law obtained from the integral form?           How can volume multiplied by a gradient equals flux through a closed surface?

is an amazing law. It is extremely useful (as far as problems framed for it are concerned :D. I do not have a real world-problem solving experience of using Gauss' Law).  However, I don't really understand why it works. What my doubt is, is this:     In the God-equation:      $$ \oint_s\vec{E}\cdot d\vec{s} = \dfrac{q_{enc}}{\epsilon_\circ} $$      $\vec{E}$ is the field at the area element $d\vec{s}$, and that field   is due to all the charges in the configuration. But the $q_{enc}$ is   the algebraic sum of only those charges that are enclosed within the   Gaussian surface. That is, to the net flux, only those charges affect that are within the surface. The contribution of the outside charges somehow cancels out. Why does it work that way?   If I knew a lot of advanced math and vector spaces and such fancy stuff, I wouldn't have asked this question. I am looking for an intuitive way of understanding its proof - if it is possible to understand without that depth of math. I do know some basic integration and surface integrals and all that (otherwise I wouldn't be able to use Gauss's Law, obviously!). So, if your answer involves these things, I'd be fine. But please don't bring in the divergence theorem etc. I tried to decipher the math behind it on wikipedia, and didn't understand a thing.


the indefinite article      the gerund      the past participle   I've always thought that 'the' is placed when you're talking about something specific. But I see people usually say with 'the' even though you're discussing something general, such as     In English grammar, the past participle refers to an action that was started and completed entirely in the past.   Why is that so?

I was reading a paragraph about lions and I came up with a question about the definite article (the).  Let me tell you first what I know about it.     1->We use the before a singular noun (when we are sure about the noun.    And the listener and the speaker both know about it).      2->We use the before a plural noun (again when we are sure about the noun,   and we are not talking generally).   So, my question is why does the writer use the here as we are not talking about any specific lion or lions. We are talking generally.  The Paragraph:     Living in the grasslands, scrub, and open woodlands of sub-Saharan   Africa, the lion is the second largest cat in the world. It is dwarfed   slightly by the tiger, which is closely related and has a very similar   body type.    Can we re-write the paragraph something like this:     Living in grasslands, scrub, and open woodlands of sub-Saharan Africa,   lions are the second largest cat in the world. They are dwarfed   slightly by tigers, they are closely related and has a very similar   body type.


I am booting multiple copies of Windows via Grub (UEFI bios). The way I've got it to work is to boot Grub, then boot Windows BCDEDIT menu, and select the correct Windows install I want from that menu. When that happens, most of the time it will reboot the computer, then I have to select Windows again from Grub menu, and then the correct version of Windows will boot (bypassing BCDEDIT Menu). Is there any way to avoid this rebooting behaviour? I've only had this issue WITH UEFI mode, with MBR this doesn't happen. I won't be going back to MBR however. Thanks!

Today I installed Windows 8.1 and it broke my GRUB. I tried to run the boot-repair GUI on a live session of Ubuntu but after the restart of the PC GRUB displays ONLY Ubuntu.   Before the installation I had on the first HD Ubuntu installed alongside with Windows 7 and the grub displayed both of them without problem.  After I installed Windows 8.1 on the second HD the boot loader(?) was replaced with the Windows one and I could select only between Windows 7 and 8 to boot, but not Ubuntu.  How can I fix GRUB now? I wish GRUB could displays all the three OSs (even if different HDs). If not possible I wish I could just choose which HD to boot and then the grub to displays correctly the OS of that HD.  This is the  (broken link).


I am new to Javascript and I am currently trying to understand the closure of it and it's use after going through many sites and w3schools which says "It makes it possible for a function to have "private" variables."  , I am trying to understand it's use , I have found some links but I did not understand it still I do not understand how closure achieves private access like c++. When you explain please explain in details as I am a beginner

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?  I have seen  given on Wikipedia, but unfortunately it did not help.


If, for some reason, the sun were to suddenly disappear altogether, I would like to know the following:   would we "feel" it first (i.e. being thrown into outer space due to no longer having anything to orbit); would we see the sun disappear at precisely the same moment that we "feel" it?;  or would we see it before we feel it (shortly before inevitably being subsequently thrown into outer space)?   For reference: light from the sun takes ~8.5 minutes to reach us here on Earth.  I have read that , however I personally would imagine that we feel it first for this reason: how could we possibly "feel" something 8.5 minutes after it has happened if it is something as major as planet Earth being thrown into outer space?  Surely we wouldn't be hurtling through space for 8.5 minutes before noticing, would we?  But then that would lead us into the realm of the Universal Speed Limit and how, in theory, nothing should be able to exceed it (except, perhaps, subatomic particles being able to communicate instantly (MUCH faster than the speed of light), but that is a whole other question and not for discussion here).  Any help would be great.

A thought experiment: Imagine the Sun is suddenly removed. We wouldn't notice a difference for 8 minutes, because that's how long light takes to get from the Sun's surface to Earth.   However, what about the Sun's gravitational effect? If gravity propagates at the speed of light, for 8 minutes the Earth will continue to follow an orbit around nothing. If however, gravity is due to a distortion of spacetime, this distortion will cease to exist as soon as the mass is removed, thus the Earth will leave through the orbit tangent, so we could observe the Sun's disappearance more quickly.  What is the state of the research around such a thought experiment? Can this be inferred from observation?


I'd like to ask if there's a proper way of avoiding 'mouseenter mouseleave' function for/to wobble the element selected?  this code came from jquery and it is working properly but when you hover mistakenly many times the navigation, it wobble the hidden elements when your mouse is already over to the element.        $('#mn_learn').bind('mouseenter mouseleave', function(){     $('.toggleLearn').slideToggle('250');   });   i did tried to check on how to avoid that but im not lucky to do that. advance thanks for the help.

I would like to delay a hover event in jquery.  I am reading from a file when user hovers over a link or label.  I don't want this event to occur immediately in case the user is just moving the mouse across the screen.  Is there a way to delay the event from firing?  Thank you.  Example code:  $(function() {     $('#container a').hover(function() {         $('
').load('ReadTextFileX.aspx',             {filename:'file.txt'},             function() {                 $(this).appendTo('#info');             }          );     },         function() { $('#info').remove(); }     }); });   UPDATE: (1/14/09) After adding the HoverIntent plugin the above code was changed to the following to implement it.  Very simple to implement.  $(function() {     hiConfig = {         sensitivity: 3, // number = sensitivity threshold (must be 1 or higher)         interval: 200, // number = milliseconds for onMouseOver polling interval         timeout: 200, // number = milliseconds delay before onMouseOut         over: function() {             $('
').load('ReadTextFileX.aspx', {filename:'file.txt'},                 function() {                    $(this).appendTo('#info');                 }              );         }, // function = onMouseOver callback (REQUIRED)         out: function() { $('#info').remove();  } // function = onMouseOut callback (REQUIRED)     }     $('#container a').hoverIntent(hiConfig) }


I have a working grid, with images and links, so when you click the image, it takes you to the link.   Here is the working Axios code. (Working means this const is part of the other code):  const grid_display = ({ url, key }) => React.createElement("div", { className: "image-item", key: key }, React.createElement("a", { href: "https://www.example.com"}, React.createElement("img", { className: "grid-img", src: url })));   So I need to add to that code, the following:   A mouseover / hover event Play a mp4 file (basically a link to a sound), via script function Keep same code, but just ADD the playing of sound NOTE: this code is all dynamic: all images, links, sounds are passed into this script from a database. Can't use any type of extra plugin . I'm looking to just add the correct line or syntax so the React.createElement statement works/adds the mouseover event or hover event.   As far as how the sound is played... any way that is fast, simple, uses minimal resources, etc. I'm thinking the sound clips will only be 5 seconds, 10 at max.  So, the better issue I'm having is, how do you put this solution...    ...in the React.createElement statements above?

I am writing a dhtml application that creates an interactive simulation of a system.  The data for the simulation is generated from another tool, and there is already a very large amount of legacy data.  Some steps in the simulation require that we play "voice-over" clips of audio. I've been unable to find an easy way to accomplish this across multiple browsers.    comes pretty close to what I need, but it will only play mp3 files, and the legacy data may contain some .wav files as well.    Does anyone have any other libraries that might help?


What is the right article for the below sentence  Consultant agrees to execute an structural engineering. Consultant agrees to execute a structural engineering.

In the following example, is it appropriate to use a or an as the indefinite article, and why?     He ate __ green apple.   I know that in the case of just "apple", it would be "an apple," but I've heard conflicting answers for "green apple," where the noun is separated from the article by an adjective.  Also, which is more appropriate in this case:     He ate  __ enormous Pop-Tart.


When I want to talk to someone and the sentence I am using has "too" or "also" or "as well" in it, I get confused and feel like I am using the wrong structure.  For example:     Friend: It's raining here          Me: I wish it was raining here too ( or I wish it was also raining here OR I wish it was raining here as well)   or         Friend: I read books           Me: I read books too (I also read books OR I read books as well)      I would appreciate it if you could tell me the correct structure or suggest an alternative for this

I have sent this e-mail to Aman also. I have sent this e-mail to Aman too.   Which one is correct? What is the exact difference between the two? Please explain.


How does the unit circle work for trigonometric ratios of obtuse angles? I know that the x coordinate is cos(θ) and the y coordinate is sin(θ). But I understand these in context of only acute angles? I don't understand why the unit circle definition works for other than acute angles? Somebody please provide me some good intuition.

How does the unit circle work for trigonometric ratios of obtuse angles? I know that the x coordinate is $cos (\theta )$ and the y coordinate is $sin (\theta )$. But I understand these in context of only acute angles? I don't understand why the unit circle definition works for other than acute angles? Somebody please provide me some good intuition.


The normal way of using AES-CBC is to XOR the IV with the first plaintext block    This way you have to pass the IV along the ciphertext.  What if instead of XORing we just put a fixed size randomIV in front of the plaintext:  Encrypt(randomIV + plaintext) = C1  And we don't have to send/tansmit separatly the IV since it is inside C1. Decryption works similarly:  Decrypt(C1) = randomIV + plaintext  And we just remove the randomData (fixed size) to end up with the plaintext.  In essence, the first block of random data, when encrypted will work EXACTLY as a randomIV since it will be XORed with the second block  Except from performance loss (having to encrypt an additional block instead of XORing), can you think why this might not be secure.

What if, instead of using CBC mode in the normal way with a random IV, I used this approach:   Use a fixed IV (like a block of 0's). Before encrypting, generate a random block and prepend it to the plaintext. After decrypting, ignore the first block.   Is this exactly the same in terms of security as using a random IV?  Also, would it make any difference if I used something like a message counter instead of a random block in step 2?


I have 103 layers which i need to save as PNG files(each layer individually) but the problem I'm haiving is;the background layer (is to be saved with each layer) how can i do this ? Kindly guide me thanks

Let's say I have some layers and a single different one, or a group of layers I want to export merged together, in a way that every single exported layer is merged with a specific layer or group of layers.  In the example below I have some layers which need to be exported into JPG or PNG, merged with the very top layer called "Blurred". In my case, I want to export the layers (Jan 8 + Blurred) and (Layer 10 + Blurred) and so on. Acting as exporting layers merged with a master layer called "Blurred".  My question in a simple way: how to apply a Master layer(s)/Group(s) in Photoshop to be exported with every layer I have?


Sanity check here...   Shouldn't these two linq queries return the same results?   Query #1:  int stateId = 2;  var streets = from s in ctx.tblStreet               where s.State_Id == stateId               && s.ParentStreet_Id == (int?)null               select s;   Query #2:  int stateId = 2; int? parentStreetId = (int?)null;  var streets = from s in ctx.tblStreet               where s.State_Id == stateId               && s.ParentStreet_Id == parentStreetId               select s;   ====== EDIT ==========  The first linq query yields the records that I expect it to, while the second linq query does not. I would expect both of them to yield the same results, but they don't.  ====== EDIT #2 ==========  tblStreet definition...  int State_Id not null  int ParentStreet_id null  ====== EDIT #3 ==========  The generated sql is different for the two queries, but I would expect it to not matter in this case, because @p1 (parentStreetId) equals (int?)null. Please note that in the queries below I removed all of the select fields and replaced them with an asterisk in order to shorten up the select and just show the where clause.  Query #1:  SELECT * WHERE ([t0].[State_Id] = @p0) AND ([t0].[ParentStreet_Id] IS NULL)  Query #2:  SELECT * WHERE ([t0].[State_Id] = @p0) AND ([t0].[ParentStreet_Id] = @p1)

I have a Category entity which has a Nullable ParentId field. When the method below is executing and the categoryId is null, the result seems null however there are categories which has null ParentId value.  What is the problem in here, what am I missing?  public IEnumerable<ICategory> GetSubCategories(long? categoryId) {     var subCategories = this.Repository.Categories.Where(c => c.ParentId == categoryId)         .ToList().Cast<ICategory>();      return subCategories; }   By the way, when I change the condition to (c.ParentId == null),  result seems normal.


How do I Explain this Combinatory? $$ \sum_{k=1}^{100} {{100} \choose {k}}2^k=3^{100}-1 $$

I'm studying for a midterm and need some help with proving summation     $$\sum\limits_{k=0}^n\binom{n}{k}2^k = 3^n$$   using the binomial theorem.  This is what I've been thinking so far:   In the binomial theorem, we set $x = 0$ and $y = 2$, so:  $3^n = (x+y)^n = \sum\limits_{k=0}^n\binom{n}{k}y^k$  $ = \sum\limits_{k=0}^n\binom{n}{k}2^k$  Am I getting this correct so far or completely wrong? Any help would be appreciated. Thanks.


My compitations: Base Case= $8-3 = 5$ is divisible by $5$  Inductive Hypothesis$=$ $8^k - 3^k = 5M$  $8^k = 5M + 3^k$ $3^k = 8^k - 5M$  My final answer is $5(11M + 11^k)$ Please tell me if I have any mistake regarding my computations.

I did some mathematical induction problems on divisibility   $9^n$ $-$ $2^n$ is divisible by 7. $4^n$ $-$ $1$ is divisible by 3. $9^n$ $-$ $4^n$ is divisible by 5.   Can these be generalized as $a^n$ $-$ $b^n$$ = (a-b)N$, where N is an integer? But why is $a^n$ $-$ $b^n$$ = (a-b)N$ ?  I also see that $6^n$ $- 5n + 4$ is divisible by $5$ which is $6-5+4$ and $7^n$$+3n + 8$ is divisible by $9$ which is $7+3+8=18=9\cdot2$.  Are they just a coincidence or is there a theory behind?  Is it about modular arithmetic?


Let there be a matrix    $$A_n=\left(\begin{matrix}4&2&\cdots&2\\2&4&\ddots&\vdots\\\vdots&\ddots&\ddots&2 \\2&\cdots&2&4\end{matrix}\right)\in M_n\left(\mathbb{Z}_7\right)$$      What is the general formula of $\det\left(A_n\right)$?   decomposition of the matrix to a sum will not help, any suggestions?

I have the following $n\times n$ matrix:  $$A=\begin{bmatrix} a & b & \ldots & b\\ b & a & \ldots & b\\ \vdots & \vdots & \ddots & \vdots\\ b & b & \ldots & a\end{bmatrix}$$  where $0 < b < a$.  I am interested in the expression for the determinant $\det[A]$ in terms of $a$, $b$ and $n$.  This seems like a trivial problem, as the matrix $A$ has such a nice structure, but my linear algebra skills are pretty rusty and I can't figure it out.  Any help would be appreciated.


I have OpenSuse 15.1 "Magic Leap" installed.  I noticed that there seems to be two conflicting commands named ss.  When I run which ss, I get this:     /usr/sbin/ss   And when I try to inspect, notice this...  >* whatis ss ss (8)               - another utility to investigate sockets   Which to me looks like the iproute2 command I expect - a modern replacement to netstat and the like. However, attempts to use this said command to for example list all active tcp connections on the machine show that the command in my default namespace is different!    See what happens with ss -t  >* ss -t su: invalid option -- 't' Try 'su --help' for more information.   Which to me looks like ss is now an alias for su, the super user util.   So, is this an OpenSuse "feature", bug or what?   Also, invoking the command from an unprivileged shell automatically summons sudo and leaves me on a root shell - further hinting at the later possibility!  I don't wish to install a deprecated netstat if there's a new, modern way to do things, but then, how do I get to the proper ss command?      UPDATE:   As per muru's suggestion, here's the output of type -a  >* type -a ss ss is aliased to `sudo su' ss is /usr/sbin/ss ss is /usr/bin/ss   Further, upon inspection with file, I find that these two "versions" of ss reported above, actually are the same. See the following...  >* file /usr/bin/ss /usr/bin/ss: symbolic link to ../sbin/ss >* file /usr/sbin/ss /usr/sbin/ss: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/l, for GNU/Linux 3.2.0, BuildID[sha1]=4cb972d442c793ac1783b508f94e7aaceaf83088, stripped >* /usr/sbin/ss --version ss utility, iproute2-ss170705   So, at the same time, ss seems to be an alias for sudo su, yet upon inspection, seems to be the iproute2 command. Weird.

An alias, such as ll is defined with the alias command.  I can check the command with things like type ll which prints  ll is aliased to `ls -l --color=auto'   or command -v ll which prints  alias ll='ls -l --color=auto'   or alias ll which also prints  alias ll='ls -l --color=auto'   but I can't seem to find where the alias was defined, i.e. a file such as .bashrc, or perhaps manually in the running shell. At this point I'm unsure if this is even possible.  Should I simply go through all files that are loaded by bash and check every one of them?


He can drive a car. He can drive cars.   I found both sentences on a website.  Could you tell me the difference.  I think 1 is more like permission and 2 is more like an ability.

I can use computers. I know how to use a computer.   Why?  And what about the followings. Which of these is the natural sentence to say?   He can teach how to use a computer. He can teach how to use computers.


I have this website where users can enter stable names to compete in games against other members.  Usually it's fine as I can just escape or use addslashes to handle apostrophes and other such characters.  What I am having an issue with is when users use a hash/pound/number sign in the stable name like the first example below or a bunch of special characters like the second example below...  #a new rising ΔMi−1 = −αΣn=1NDi[n][Σj∈C{i}Fji[n - 1] + Fexti[[n-1]]   When this goes over as part of a url to a second page and the stable is a appended to the URL to be used as a GET variable to pull details from the database, nothing is returned.  I have tried using urlencode, rawurlencode, and percent encoding on the $stable variable as is suggested in other questions on this site but nothing seems to work.  Below is a sample of the code that has the issue...  Referring URL --- mydomain.com/stable.php?stable=#a new rising&season=59  Code for stable.php...  $stable = addslashes($_GET["stable"]); $season = $_GET['season'];  echo $stable;  $sql = "SELECT total, wins, loss, ties FROM History_Stables WHERE stable = '$stable' AND season = '$season'"; $res = $link->query($sql); $arr = $res->fetch_array();  $pts = $arr[total]; $w = $arr[wins]; $l = $arr[loss]; $t = $arr[ties];   And so on.  What exactly am I missing here to get the hash/pound/number sign to be properly encoded as %23?

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


In the winter, are not all electronics heating the house - thus no energy is wasted?  Considering the energy I'm paying for: If I leave my computer running while I'm out, how much energy is actually wasted in the winter? Is all of the energy used in the computer expelled as heat into my home?  To be even more specific: If my computer ran at a constant 500 watts and I had a 500 watt space heater, would they heat my home the same (thus cost the same)? If so, wouldn't it make sense to leave the computer on in the winter, since the heat produced is not really wasted? That way I always have instant access.  (Ignore variables like computer lifespans, gas furnaces, and cost-effectiveness for the sake of the question.)

Consider a computer CPU consuming electrical energy to perform calculations and consequently emitting heat.  Assumption: That a CPU consuming x Watts of power, emits the same amount of heat as an incandescent heating element which consumes the same amount of power.  The rest of the question assumes that this is true: the energy has to go somewhere, and I can't see that the outcome of the calculations counts as "somewhere".  I've long repeated the claim that "wasteful" appliances such as incandescent lightbulbs, over-full kettles, computers left running, etc. are not wasting power if we make the assumptions:   the appliance is in a room which we aim to maintain at above a certain temperature, warmer than the external temperature (cf a home in winter) the room leaks heat to the outside faster than the "wasteful" appliances emit heat. the room contains an electric heater the electric heater is regulated by a thermostat   In these circumstances, I think (?), if a light bulb produces excess heat, its only effect is to cause the thermostat to switch off sooner, so what energy you've "wasted" in the light bulb, is "saved" at the heater.  I don't think that's controversial.  But my question is:   If a CPU does useful work, and emits all the input energy as heat as a side effect But a heating element emits the same heat, without doing useful work Is it therefore wasteful to use heating elements? Is it more efficient to (for example) run  on a CPU, to get "free" computation as a side-effect of heating?   One reason to heat a room with a heating element, rather than with CPUs, is that the heating element is much cheaper to produce. But ignoring the initial cost of the hardware, would a "heater" made out of 20 CPUs, each running at full capacity and consuming 50W each, output less thermal heat than a 1KW element that does nothing else useful?  To be useful, of course, the CPUs would need to output the result of their computations, which would account for a tiny amount of energy. Let's assume that's negligible.  I'm sure there's a flaw in there somewhere; probably that the assumption above is false. What have I missed?