Before explaining the situation I have read  which deals with the problem and shows a solution.   The problem is as follows:  $\textrm{Prove:}$  $\sin 2\omega+\sin 2\phi+\sin 2\psi= 4 \sin\omega \sin\phi \sin\psi$  $\textrm{Given this condition:}$  $$\omega +\phi+ \psi= \pi$$  However I tried to solve it in a different way, without appending the double angles and summing them together at the end, as it has been suggested by one user to the OP in the preceding question.  My attempt differs from the OP as he has not mentioned an effort into solve the problem, to which it is to be exposed below. In request of proof reading.  Therefore, in my attempt to solve this problem I did what I felt obvious and that was to take the sine function to the whole condition as shown below:  $$\sin \left (\omega +\phi+ \psi \right )= \sin \left ( \pi \right )$$  Grouping:  $$\sin \left (\omega + \left(\phi+ \psi\right) \right )= \sin \left ( \pi \right )$$  $$\sin \left (\omega + \left(\phi+ \psi\right) \right )=  0 $$  $$\sin \left(\omega\right) \cos \left(\phi+ \psi\right) + \cos \left(\omega\right) \sin \left(\phi+ \psi\right) = 0 $$  $$\sin \omega \left(\cos \phi \cos \psi - \sin \phi \sin \psi\right) + \cos \omega \left(\sin \phi \cos \psi + \cos \phi \sin \psi \right) = 0 $$  $$\sin \omega \cos \phi \cos \psi - \sin \omega \sin \phi \sin \psi + \cos \omega \sin \phi \cos \psi + \cos \omega \cos \phi \sin \psi = 0$$  $$\sin \omega \cos \phi \cos \psi + \cos \omega \sin \phi \cos \psi + \cos \omega \cos \phi \sin \psi = \sin \omega \sin \phi \sin \psi$$  $$\sin \omega \left(\cos \phi \cos \psi\right) + \cos \omega \left(\sin \phi \cos \psi + \cos \phi \sin \psi\right) = \sin \omega \sin \phi \sin \psi$$  Using product to sum identity:  $\sin \omega \left(\frac{1}{2}(\cos (\phi + \psi) + \cos \left(\phi -\psi\right))\right) + \cos \omega \left(\frac{1}{2} \left(\sin \phi \cos \psi + \cos \phi \sin \psi\right)\right) = \sin \omega \sin \phi \sin \psi$  $\sin \omega \left(\frac{1}{2}(\cos (\phi + \psi) + \cos \left(\phi -\psi\right))\right) $ $+ \cos \omega \left(\frac{1}{2} \sin (\phi + \psi) + \sin (\phi-\psi) + \sin(\phi+\psi) - \sin(\phi-\psi)\right)= \sin \omega \sin \phi \sin \psi$  $\sin \omega \left(\frac{1}{2}(\cos (\phi + \psi) + \cos \left(\phi -\psi\right))\right)$ $ + \cos \omega \left(\frac{1}{2} \left(\sin (\phi + \psi) + \sin (\phi-\psi) + \sin(\phi+\psi) - \sin(\phi-\psi)\right)\right)= \sin \omega \sin \phi \sin \psi$  Simplifying similar terms:  $\sin \omega \left(\frac{1}{2}(\cos (\phi + \psi) + \cos \left(\phi -\psi\right))\right) + \cos \omega \left(\frac{1}{2} \left( 2 \sin (\phi + \psi) \right)\right)= \sin \omega \sin \phi \sin \psi$  Then multiplying all by $4$  $$2 \sin \omega \left((\cos (\phi + \psi) + \cos \left(\phi -\psi\right))\right) + 2 \cos \omega \left( \left( 2 \sin (\phi + \psi) \right)\right)= 4 \sin \omega \sin \phi \sin \psi$$  By returning to the initial condition: $\omega +\phi + \psi =\pi$  $$2 \sin \omega (\cos (\pi-\psi)+\cos(\phi-\psi))+2 \cos \omega (2 \sin(\pi-\psi))= 4 \sin \omega \sin \phi \sin \psi$$  $$2 \sin (-\cos \psi + \cos (\phi - \psi)) + 2 \cos \omega ( 2 \sin \psi) = 4 \sin \omega \sin \phi \sin \psi$$  And that's how far I went, I feel I'm almost there but I don't know if I am in the right path or maybe not. Can somebody instruct me where exactly can I relate the double angle of omega, phi and psi?. Why is my method not working?  what did I missed or what should I do to my steps to prove this identity?.

Prove that $\sin(2A)+\sin(2B)+\sin(2C)=4\sin(A)\sin(B)\sin(C)$ when $A,B,C$ are angles of a triangle   This question came up in a miscellaneous problem set I have been working on to refresh my memory on several topics I did earlier this year. I have tried changing $4\sin(A)\sin(B)\sin(C)$ to  $$4\sin(B+C)\sin(A+C)\sin(A+B)$$ by making substitutions by reorganizing $A+B+C=\pi$. I then did the same thing to the other side to get $$-2(\sin(B+C)\cos(B+C)+\sin(A+C)\cos(A+C)+\sin(A+B)\cos(A+B))$$ and then tried using the compound angle formula to see if i got an equality. However the whole thing became one huge mess and I didn't seem to get any closer to the solution. I am pretty sure there is some simpler way of proving the equality, but I can't seem to figure it out. Maybe there is a geometric interpretation or maybe it can be done using just algebra and trig. Any hint's would be appreciated (I would prefer an algebraic approach, but it would be nice to see some geometric proofs as well)


S.O. presented my this review for a first-post answer:    but when I open the question    I saw that the user has a reputation of 10.5k!  How could be possible? Had I misunderstood first-post review mean?

I recently received this rather amusing message while reviewing a user's first post:  Congratulations! This was only a test, designed to make sure you were paying attention. This post has already been removed, but thanks for taking time to leave feedback for the author.   What is the purpose of this test? How does the audit work? What happens if I fail? Why was the system expecting me to negatively review a good post, or positively review a bad post? A review is obviously an audit. Should I report it? Do review audits count toward the Reviewer badge? Do robo-reviewers dream of electric sheep?


PHP - Some special character is appearing as question mark�  while displaying.  I have added the utf-8 encoding for both html and php but its not working       <!DOCTYPE html>          <meta http-equiv="Content-Type" content="text/html;charset=UTF-8">     <meta http-equiv="X-UA-Compatible" content="IE=edge">     <meta name="viewport" content="width=device-width, initial-scale=1">                <?php       require_once 'db_connect.php';      header('Content-Type: text/html; charset=utf-8');     $output = '';        $connect = mysqli_connect("localhost", "root", "", "appsrx1a_skyfler");       $query = "SELECT * FROM candidate_tabletest where id =      '".$_POST["member_id"]."'";    $result = mysqli_query($connect, $query);      ?>
          <?php     while($row = mysqli_fetch_array($result))     {
                    Address	                    <?php echo $row["address"];?>

      <?php             }   ?>
           In database the content of Address field is :- "H.No 2 – D, L.C.H, SAIDABADCOLONY, HYDERABAD – 59"  but in when it echoes the address it shows :- "H.No 2 � D, L.C.H, SAIDABADCOLONY, HYDERABAD � 59."  I have made some research but i have added the meta tag for utf which were mentioned in many documentation . What might be the solution for this ?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I have chosen to use the F1-F12 keys with their original -PC- behavior, because I want F5 to refresh the page in Firefox! (and not control the backlight of the keyboard)  Now I would like to "remap" the Volume Up/Volume Down key as originaly intended: F11 and F12 keys (I'm used to that). I don't want to have to press Fn everytime.  I've searched everywhere I can't find a way to do that (for now I have to press Fn+F11 and Fn+F12).

I want to override F1 and F2 behavior, since I have external display and Mac can't control display's brightness. The rest of the keys should retain their non Fx  I know about "Use all F1-F12 keys as standard function keys.", but I don't want to change all of the keys to be F when pressed, just some of them. (For me single press music and volume control is necessary.)  Is there a way to pick some of the function keys to default to numbered function instead of the "Apple" definitions system wide?


For the last 2 days, since there've been upgrade of server, I've noticed that NO reputation is being attributed for edits. Is it a bug? And I don't know if there's a place where I can review if my edits has been accepted or rejected. But seem to me that there is a problem with reputation attribution. Can someone confirm this please?

On Stack Exchange, users may gain a certain level of reputation.  What does reputation do? How can a user gain or lose reputation?   See also   in the Help Center  - Maximum amount of votes a user can use in a day and reputation requirements to vote.  - How to get an exact overview of the actions that got you your reputation.  - A full list of all privileges granted at each reputation level on all sites.


I am travelling with an Afghan passport and Canadian permanent resident card from Vancouver (YVR) to Kabul (KBL) via London (LHR) and Dubai (DXB) with two separate ticket bookings. The first one is with British Airways from YVR-LHR-DXB and the second from DXB-KBL is with Emirates.  I will arrive in Dubai T1 at 7:30 a.m. and my next flight DXB-KBL with Emirates leaves from Terminal 3 at 9:55 a.m. on the very same day with only 2.5 hours layover in Dubai.  I am carrying just my hand luggage.  I do not have Dubai transit visa, so can I just walk from T1 To T3 and get on board to my next flight with Emirates without the Dubai transit visa or without going through any immigration/custom clearance?

Do I need a transit visa for a layover via airports in the UAE, such as Dubai International Airport or Abu Dhabi International Airport? If so, what are the requirements for such a visa? Can I get the transit visa on arrival?


Considering the example below, does PHP activerecord prevent SQL injection on basic create? I can find numerous examples and instructions on the finders, but nothing on the safety of what I do here.      $p = new Person();     $p->firstname = $_POST["firstname"];     $p->emailaddress = $email_enc; (encoded from $_POST["email"])     $p->save();   EDIT: I'm not asking about preventing "ordinary" PHP SQL injection. This question is specific for PHP activerecord basic CRUD actions

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?


I understand that if you do not correctly reheat a baked potato bacteria can set in botulism. what is the correct temperature you need to avoid temperature abuse.  Also can you use the baked potato for other uses ie hash brown that need to be reheated

I thought I remembered hearing the food agency  say that you should never reheat chicken meat after the initial cooking. However, I cannot find the statement of it anymore. Now I'm starting to suspect my memory.  Could this statement be true?  Is it unsafe to reheat chicken?


I have two histograms. Together they tell one story, so I want to put them in one figure. I want to stick to one column format, therefore I want them vertically. How can I do that?  I've only seen answers on how to put them next to each other horizentally.  EDIT: turns out that I can simply repeat \includegraphics twice and that's it!! Okay, so how can I put sub-label for each one? like (a) and (b) ?? so that I can talk about them in the caption?

I have 6 images, and I want to align them in this way  (a)image1 (c)image3 (e)image5  (b)image2 (d)image4 (f)image6  Any one know how to do that?  The problem for me is how to make (a), (b),..., (f) in vertical direction.


The issue was described in 1 or 2 post already but my case goes little more, since none of the mentioned causes are not my case:  I do not have trash  I checked my media and galleries  Putting a ridiculous name (like: "2015555555" in stead of 2015) still produce "2015555555-2" Do not know what to do next...

Here's something interesting I noticed today - it is not possible to name a post a number - no matter what theme you use, and even if you name a post a long number that has no tag or post-name or category name conflicts, you will still get 2015 or 1826628 renamed as 2015-2 or 1826628-2.  I assume this isn't a bug, but I also don't see why you can't have mysite.com/20 or similar as a permalink to a post, when you have it named "20", and permalinks are set to postname.


I Have a simple visualforce page on which ik want to prefill a lookup field with a contactid to create a new record. I used the Id of the customfield Contactpersoon__c and used CF before the lookup ID as I found in the documetation of URL Hacking. I added a contactid as value ending with _lkid as it is a lookup according to URL hacking.  My page loads without the field beiing prefilled why is this not working?  Visualforce:  <apex:page standardcontroller="Relatie_Contact__c"  showHeader="false"   applyBodyTag="false" lightningStylesheets="true">     <apex:slds />     <div class="slds-scope">         <apex:sectionHeader title="" subtitle="Relatie contact"/>         <apex:form >             <apex:pageBlock >                 <apex:pageBlockButtons location="bottom" >                     <apex:commandButton action="{!save}" value="Save"/>                        </apex:pageBlockButtons>                 <apex:pageBlockSection >                     <apex:pageBlockTable value="{!Relatie_Contact__c}" var="r"  >                         <apex:column style="width:250px">                             <apex:facet name="header">Contactpersoon</apex:facet>                              <apex:inputField value="{!r.Contactpersoon__c}"/>                         </apex:column>                         <apex:column style="width:250px">                             <apex:facet name="header">Relatiesoort</apex:facet>                              <apex:inputField value="{!r.Relatiesoort__c}"/>                         </apex:column>                         <apex:column style="width:250px">                             <apex:facet name="header">Organisatie</apex:facet>                              <apex:inputField value="{!r.Organisatie__c}"/>                          </apex:column>                     </apex:pageBlockTable>                 </apex:pageBlockSection>             </apex:pageBlock>         </apex:form>     </div> </apex:page>   URL:  var url = '/apex/NieuweRelatie?CF00N5800000BNqkB=0039E00000LifHz_lkid';

I have the following URL hack but it is not working any ideas? The Asset.Account is a lookup field, is that the issue?  /02i/e?CF00NW0000000mpDu={!Asset.Account}&CF00NW0000000mpDu_lkid={!Asset.AccountId}


I am going to apply for a postdoc position. Applicants are asked to send their CV,research statement, name of referees etc as a single PDF file directly mailing to the "principle investigator" of that project. I was wondering whether I need to add my cover letter into that PDF file or just write it in my email itself.

When applying for example to a postdoc position, is it appropriate to write the text of the cover letter directly into the email, or should it be attached as a seperate file?  One advantage of stating the content of the cover letter directly in the email I could see is that there are good changes that the potential future employer reads it before opening any other ducuments, such as the curriculum vitae, list of publications, etc that might be attached.


I have a small question about simple groups: When we're decomposing a group $G$ we take a non-trivial normal subgroup of maximum order $G_1$ so that $\frac{G}{G_1}$ is simple and so on. But why is $\frac{G}{G_1}$ simple? I thought it had to do with the fact that $G_1$ is of maximum order, so there is no 'bigger' normal subgroup in $G$?

I need to prove that $H$ is a maximal normal subgroup of $G$ if and only if $G/H$ is simple.  My proof to the $(\Rightarrow)$ direction seems too much trivial:  Let us assume there exist $A$ so that $A/H\lhd G/H$. Then by definion, $H$ must be normal in $A$. Because $H$ is maximal, we get $H=A$ and therefore $A/H={1}$  Is it correct?  Update:  Now I see that I need to prove that not only $A\lhd H$ but also $A\lhd G$. Assumig I have proven that, is the proof correct?


Some time ago, I've asked a question on Stack Overflow and haven't received an answer. I'm really interested in answers to my question. How can I reopen my question or bump it up in the queue without creating a new question with the same body?

I asked a question almost as soon as I got my account. I got a few decent answers, but none of them helped solve my problem. The question has long since become buried by newer questions, and there's still no accepted answer. Unfortunately, because there are quite a few answers with votes, to a casual observer it probably looks like the question was answered and I just neglected to mark an answer as accepted, and the system does not consider it "unanswered".  Or, I asked a question that was a bit more difficult to answer. After waiting for some time, I received no answers, little or no comments, and only a few views. The question does show up in the "unanswered" list, but no one has answered my question.  In either case, what's the protocol for me to try to get this question answered?  I see several options:   Post the question a second time, possibly linking to the original, to get attention for the original question. This is encouraged on sites like Reddit.  However, it's probably not appropriate here, since we're encouraged to check for duplicates and not submit a question that's already been asked by someone else, so this probably falls under that heading. Wait for some kind of wiki-like talk page to be implemented, then post a plea on the talk page for input and hope that activity on the talk page bumps up the question. Edit the question, but do nothing further on the Stack Exchange site. If I edit my post to say that I haven't accepted any of the current answers but am looking for more, then the question might get answered eventually by people browsing through old questions to find something they can answer. Post the question on other sites, but link to my original question on Stack Exchange. People will either answer here, or they'll answer on the other site and I can post the accepted answer here myself.  This might be considered spamming, so it might be better to do this without the link.      For more information, see the "" page in the .


I am novice in the template programming.  What is the problem in this simple function?  template<class T> void myFunction() {     basic_string<T>::size_type i = 0;  }   I cannot compile it?!  Changing class to typename does not solve the problem?

In templates, where and why do I have to put typename and template on dependent names? What exactly are dependent names anyway?    I have the following code:  template <typename T, typename Tail> // Tail will be a UnionNode too. struct UnionNode : public Tail {     // ...     template<typename U> struct inUnion {         // Q: where to add typename/template here?         typedef Tail::inUnion<U> dummy;      };     template< > struct inUnion<T> {     }; }; template <typename T> // For the last node Tn. struct UnionNode<T, void> {     // ...     template<typename U> struct inUnion {         char fail[ -2 + (sizeof(U)%2) ]; // Cannot be instantiated for any U     };     template< > struct inUnion<T> {     }; };   The problem I have is in the typedef Tail::inUnion<U> dummy line. I'm fairly certain that inUnion is a dependent name, and VC++ is quite right in choking on it. I also know that I should be able to add template somewhere to tell the compiler that inUnion is a template-id. But where exactly? And should it then assume that inUnion is a class template, i.e. inUnion<U> names a type and not a function?


I want to make a USB cell phone charger. I know USB operates in 5 volts which means i need to drop down voltage if i have battery potential greater than 5 Volts. I have 12 volts sealed lead acid battery (SLA) of capacity 9AH. I need to drop down the voltage for which i am using LM2596 buck regulator ( Switching power supply) and it can deliver 3 amperes of current. But my cell phone charger(came with the product) is rated for 2A. So i was wondering how can i limit the current so that it doesnot blow my Cell phone. Thanks

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


I have an algorithm that works with  insertion, deletion and substitution counts of a word compared to a format. I can find these counts in Python like below, fuzzy_counts give me these error counts:   import regex regex_pattern = r"([0-9]{6}){e}" word = '12345' regex_object = regex.fullmatch(regex_pattern, word, regex.ENHANCEMATCH) print(regex_object)   Output:   <regex.Match object; span=(0, 5), match='12345', fuzzy_counts=(0, 0, 1)>   However I need this same thing in Java.  Thanks for the help.

I'm looking for a high performance Java library for fuzzy string search.  There are numerous algorithms to find similar strings, Levenshtein distance, Daitch-Mokotoff Soundex, n-grams etc.  What Java implementations exists? Pros and cons for them? I'm aware of Lucene, any other solution or Lucene is best?  I found these, does anyone have experience with them?


I've georeferenced an old map on qgis and layered it on top of OSM, I want to do a class project and for it I would like to pinpoint certain areas on the map of which I have old photographs. I would like to know if it's possible to pinpoint the locations and attach photographs, so you can see photos of what that place used to look like, as well as write textual information. I know that you can do text annotations, but how about images?   I would like it to be something similar to like when you get locations pinpointed on google maps and when you press on the pinpoint you get the photo and information.

Say for example, if there's a point data with old trees, then when you use the identify tool, you can see the photograph of the tree  Or even one level further, the labels displaying these images right away without any clicking needed  I believe the term is file streaming?


$$ \sum_{n=1}^{\infty} \frac{(n-1)!}{(x+1)(x+2)..... (x+n)}. $$ I tried solving it by inserting some values $\frac{1}{x+1}$ +$\frac{1}{(x+1)(x+2)}$+$\frac{2}{(x+1)(x+2)(x+3)}$ $\frac{1}{x+1}$+$\frac{1}{x+1}$-$\frac{1}{x+2}$+$\frac{1}{x+1}$-$\frac{1}{x+2}$+$\frac{1}{x+3}$-$\frac{1}{x+2}$ This gives me a hint that $\frac{1}{x+1}$ this comes n times -$\frac{1}{x+2}$ comes n-1times and so on But since the terms tend to infinity I dont find it useful so any hint? Answer is $\frac{1}{x}$

I am trying to evaluate the following sum. Here $x\in\mathbb{R^{+}}$. $$f(x)=\sum_{n=1}^{\infty}\frac{(n-1)!}{\prod_{r=1}^{n}(x+r)}$$ At present I do not know how to proceed. Any hints are appreciated. Thanks.


I called Ajax on button click, and I got response with link. Now I want to do some action on that link but I cant, why?  here is the ajax call:  $( document ).ready(function() {   jQuery(".rateReset").click(function(){      var data_item = jQuery(this).attr("data-item");      var data_target = jQuery(this).attr("data-target");      var me = this;      jQuery.ajax({         type: "POST",         url: "likevoting.php?data_item="+data_item+"&data_target="+data_target+"&interchange=yes",         success: function(data){            jQuery(me).closest("div.rateWrapper").html(data);         }    }); });   I got response like:  some text  lorem ipsume...  Now I want to add click event on 'link' text, how to do this.  Thanks

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


If one's ultimate goal is to obtain tenure (as a professor of chemistry or some other STEM field, for example), is it honestly better to have a more well-known professor as a PI versus an assistant professor (assuming both have equally good research and are in top-tier institutions)?

Long story short, I have left behind a toxic PI and now I am considering applying for another labs at different demographic locations, however, I found it little bit harder to make a thorough decision. One of the challenges that hinders me to make a selection is different feedback from many students from different labs, I have asked them and there is their response as follows.   A star professor at a high ranking university:  One of his student told me he doesn't have time to manage the lab by himself and as a sequence, he hired postdocs to be intermediate between him and his students. In retrospect, the student informed that he had tried to leave the lab at the beginning, however, they continue and mentioning that he benefit from his PI's reputation. Adding that, he and other colleagues suffered from anxiety and chronic stress due to the demand of having highly quality research papers. Intermediate professor not very well: His student told me he is not qualified to work with students, but the student told me that she doesn't feel so much pressure on her research. Junior PI: I think it could be risky as I don't have any background about their supervision history. However, what makes interested to contact them as they did good research and we have the same passion for this research line which triggers me to contact them.   My previous experience with ex-PI, he was not junior and not star, but he did research for more than 14 years, however, he didn't help me in my research or even writing papers besides being abusive and very destructive person.  The question is : If am going to select the new PI which very critical decision, how I should consider these scenarios, for sure, I avoid PI in  the influence circle of the ex-PI as I have been advised before, but what are other key corners I should bear in my mind.  I know we cannot make sweeping generalization, however, I would like to hear from the academia community if your have any prior experience or recommendation I should consider to make a reasonable decision regarding the PI selection.


I have a problem that occurs after installing Ubuntu 19.04 on my laptop. After installing it, load screen with Ubuntu logo appears and the screen resolution is not as it's supposed to be(as it was when I booted installation form USB). After it's done loading, black screen with list of tasks appears and with green oks on the left side and that is where it freezes. Any kind of help would be great!

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I've a PHP page in which i define a JS variable at the beginning of it  <script>   var accountType = 1; </script>   Someone told me to save this variable in a JS file and add auto change version to the file like  <script src="/template/assets/js/type.js?v=<?php echo time();?>"></script>   I feel that's not the proper way to solve this issue, Is there any proper method to stop browser from caching JS  tags ?  Thanks in advance

Our investigations have shown us that not all browsers respect the HTTP cache directives in a uniform manner.  For security reasons we do not want certain pages in our application to be cached, ever, by the web browser. This must work for at least the following browsers:   Internet Explorer 6+ Firefox 1.5+ Safari 3+ Opera 9+ Chrome   Our requirement came from a security test. After logging out from our website you could press the back button and view cached pages.


as all know this syntax will print file is empty   [ -s file.name ] || echo "file is empty"   but what in case file is with spaces or TAB or blank spaces ? , but without any real character as a-z 1-9 and so on  so I use this  [[ $(tr -d "\r\n" < file.name |wc -c) -eq 0 ]] && echo "File has no content"   but when we set that  echo "       " >file.name   then the follwing syntax will not print - File has no content   [[ $(tr -d "\r\n" < file.name |wc -c) -eq 0 ]] && echo "File has no content"    so we are in trouble here  how to verify file is empty but can include spaces / TABs / blank  or empty without anything  goal - verify file is empty but can include spaces / tab /blank lines , or empty without any spaces / blank lines / empty tab

This will notify us if the file is empty:  [[ ! -s $file ]] && echo "hello there I am empty file !!!"   But how to check if a file has blank spaces (spaces or tabs)?   empty file can include empty spaces / TAB


I am trying to retrieve the translation for a custom picklist values , using  REST  I think i need to retrieve CustomObjectTranslation :    I don't see it when i query : /services/metadata/v46.0/components/  I am not able to find the REST request URL to get the translations.  For example,    i have Contact.PreferedColor__c which is a Custom Picklist. I have added translations into the workbench, for french fr and englich en_US. I want to query : /services/metadata/v46.0/components/xxx and retrieve the translations   What may be xxx :) ? Is it available with REST call ?   Thanks for your help

I'm trying to retrieve the translations in translation workbench to add to Stash. My sample .xml file is below.  <?xml version="1.0" encoding="UTF-8"?> <Package xmlns="http://soap.sforce.com/2006/04/metadata"> <types>     <members>Sample_Object__c-es_CO</members>     <name>CustomObjectTranslation</name> </types>     <version>37.0</version> </Package>   I am able to successfully retrieve the object, but the file does not contain any of the translations that I have added. I have verified that I am using the correct sandbox, I verified the object name, I verified that I added the translations in my sandbox, but still no luck.  The sample output in the file is below:  <?xml version="1.0" encoding="UTF-8"?> <CustomObjectTranslation xmlns="http://soap.sforce.com/2006/04/metadata">     <caseValues>         <plural>false</plural>         <value><!-- Sample Object --></value>     </caseValues>     <caseValues>         <plural>true</plural>         <value><!-- Sample Object --></value>     </caseValues>     <gender><!-- Feminine --></gender>     <nameFieldLabel><!-- Sample Object Name --></nameFieldLabel> </CustomObjectTranslation>


I'm a newcomer to TeX trying to run skakdoc.tex from  .  I cannot get it to compile correctly using pdflatex.  It gives  ! undefined control sequence <recently read> \c@lor@to@ps   It seems to compile alright with xelatex, though no squares are highlighted. (Expecting highlighted squares based on the ps file in the link and the error)  My setup: proTeXt, Basic MikTeX installed. Also installed pstricks and other possible related packages. Using notepad++ to run pdflatex.

I thought that PSTricks package was not possible to use in pdfLaTeX but .   How can I force pdfLaTeX to use PSTricks then?


I would like to add author information on a page which is not the title page.  Something like  \documentclass[12pt,a4paper]{book} \usepackage[latin1]{inputenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{graphicx} \usepackage[left=2.00cm, right=2.00cm, top=2.00cm, bottom=2.00cm]{geometry} \title{} \author{} \begin{document}     \date{}     \maketitle       \chapter{New Chapter}     Authors      Institutions \end{document}   The author information will need to go on a chapter page underneath the chapter heading.  How can I accomplish this?

I want to include the values of author, date, and title in my use of fancyhdr in a document that uses \maketitle. Googling about, I saw that @date, etc. can access the date, etc., values set in the document preamble. It works fine, provided \maketitle is not used. Here's a minimal working example:  \documentclass{article}  \title{Things about Stuff} \author{Someone} \date{Somewhen}  \begin{document}  %\maketitle  %Toggle comment and:  Now you see them, now you don't.  \makeatletter \@date \@author \@title \makeatother  \end{document}   So, 1) why does the use of \maketitle cause subsequent invocation of @date, etc. to yield nothing, and 2) how can I access the value of \date, etc after the use of \maketitle?


This was a question on a worksheet during my first week in a class on Electromagnetism. The answer is essentially:     No. Life would be no different if electrons were positively charged and protons were negatively charged. Opposite charges would still attract, and like charges would still repel. The designation of charges as positive and negative is merely a definition.   But how would we have negative charges within the nucleus? Taking a look at the , it seems that down quarks are required in this new "negative proton" to help with creating the pion to "transmit a residual part of the strong force even between colorless hadrons".  I tried to set out and try to find a particle with (-1) charge with a down quark (by going through this ) but all the particles are not stable with the exception of two unknown:   Bottom Xi Baryon Double Bottom Xi Baryon   Assuming one of the above are stable, could the strong force act between one of them and a neutron, implying its alright to have a negatively charged nucleus?  Edit: If it wasn't clear, my question concerned whether or not there existed stable baryons of $-1$ charge with down quarks that could "replace" the proton.

I recently came to know about the Conventional Current vs. Electron Flow issue. Doing some search I found that the reason for this is that Benjamin Franklin made a mistake when naming positive and negative charges. There is even this little comic about that   My question is, how can a naming convention be wrong? Perhaps I don't understand what is the actual mistake here, I don't know. But I don't see how a naming convention could be wrong or right. There is no right and wrong about that. It could've been any other name, like charge A and charge B.  I'll appreciate anyone can help me understand what is wrong in all this.


I was just playing around with data types and landed on this dilemma. Can anyone here explain me the reason  #include<iostream> using namespace std;  int main() {      float a= 0.7;     if(a < 0.7)         cout<<"Yes";     else         cout<<"No";     return 0; }   I know it is because automatically 0.7 as a literal will be of double.  #include<iostream> using namespace std; int main(){      float a= 0.8;     if(a < 0.8)     cout<<"Yes";     else     cout<<"No";     return 0; }

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Water inside bucket is rotated (by spoon or something) to flow in circular motion. An object kept in the bucket tends to be at the center of the bucket. Why is that?

At xmas, I had a cup of tea with some debris at the bottom from the leaves.  With less than an inch of tea left, I'd shake the cup to get a little vortex going, then stop shaking and watch it spin.  At first, the particles were dispersed fairly evenly throughout the liquid, but as time went on (and the vortex slowed, although I don't know if it's relevant) the particles would collect in the middle, until, by the time the liquid appeared to almost no longer be turning, all the little bits were collected in this nice neat pile in the center.  What's the physical explanation of the accumulation of particles in the middle?  My guess is that it's something to do with a larger radius costing the particles more work through friction...


What is the difference between these two expressions?        Your hair needs brushing.   Your hair needs to be brushed.

I'm from Central Pennsylvania, and apparently, we have a strange language construct in this area. I was recently talking about how "my car needs washed" to a friend from NJ, and she told me that my sentence was grammatically incorrect.   I realize she's right, and I realize my options are "my car needs to be washed" or "my car needs washing". But I'm not clear on the precise rule being invoked.


Scenario  The party happens across a Flail snail being mobbed by some bugbears (Random encounter). They killed the bugbears and the Flail snail started wailing (All of its tentacles were severed and dead). Can the druid cast regenerate on it to reattach the tentacles (Snail did not reflect the spell).   What other spells or methods could be used to save the flail snail, especially for lower level parties?

I recently had my nose bitten off by a berserker and smell is surprisingly hard to live without.   I have had some past trouble with wishes (from a ring of three wishes) so I'm reluctant to make another wish. Also I don't think this is worth wasting my last wish over anyway.  My DM is evil so I'll probably end up with a Mephit's nose or something if I wish for it back.   Can anyone tell me another way of regaining body parts?


Asking for a friend who is looking for a short story, but cannot remember the title. The friend thinks it is by Le Guin, but the anthologies she had didn’t contain it. "The story is about a land where people are given some kind of an aptitude test by the government and careers planned for them based on the test results. The main character had always wanted to be an artist, but the test says that he has to be a miner. He rails and rants and appeals, but to no avail. So he ends up in this mining place and just hates it. He keeps appealing, but all this requests are turned down. So he slowly adjusts to the place, its roughness and brutality – and makes a life. "One day he discovers some strange minerals in the mines, and takes it home to play with. Over time he creates a whole array of artistic creations that others come to like. And so his life goes on. And then one day there is an urgent missive from the ministry/government that they had screwed up – and that his tests had indeed showed that he needed to be an artist. This never happens they said, but we will make it right. "So he is shipped off to this artists paradise. And once there he realizes he hates these people – they are too airy-fairy and just live in their own heads, and that he wants to go back to his life as a miner and that over time he had come to like its roughness and the space he had built within it."

Story about a planet-sized multi-celled creature collecting life to ultimately spread (seed)pods of life throughout the universe.  I'm looking to find an English short science fiction story that I think I read in a sci-fi anthology (possibly Asimov) as a child during the early 90's in England.  I remember nothing of use about the actual book or cover but the story details have stuck in my mind and the memory has often resurfaced enough to require help finding it so I can reread it.  The story is of a planet-sized smooth black object/creature appearing (close to earth?) and astronauts being sent to explore and find out what it is. They land and find they can push(sink) into the surface, far enough to pass through the outer skin and find themselves in an earth-like paradise with air, mountains, trees, rivers etc.   The astronauts find that they can also push through the floor of this first paradise into yet another 'bubble' or pod of this earth-like environment and find many more similar 'pods' in all directions and ultimately decide to colonise (maybe with unwanted earth prisoners at first) the expansive spaces of this new world/planet/creature thing.   During the story there is a narrative of an 'elder being' teaching its young about their own purpose (I always imagined 'story-time' around a campfire) and the story ends with the 'elder' exploding and all the child environmental 'pods' and their containing colony of humans being flung to the corners of the universe to populate it with the life that they now contained.      The details of the story are as follows:     Planet-sized object appeared in space that is smooth, shiny, and black. A male and a female astronaut sent to explore the object.  Detailed description of spacecraft landing badly on the object too hard and finding that the spacecraft sank into the surface without damage, leading to them trying to push through the outer skin.   The pods each contain a perfectly viable earth-like environment that is later colonised. Sub-narrative by an unknown consciousness somewhat like an elder teaching the young it's history or purpose. The 'elder' creature was conscious (possibly excited?) of being filled with life as humans colonise. The ending being that the 'elder' explodes and child pods split and fly off in all directions taking the human colonies with them for the purpose of populating the universe.   I remember picturing this object as a bunch of biological cells, each a copy of the original (possibly cell-division during the story itself) with a virus-like spawning in a host system (the universe) by splitting apart to repeat the process in other areas when they have enough (human) life to do so. Not a specifically stated part of the story but my own interpretation over the years since I first read it.  This story was part of an anthology which contained another short story about a metal bar appearing from nowhere (next to someone's armchair, of all places) and the metal is the hardest substance possible. Attempts to cut, shape or bend it fail, but when other metals are welded to the metal they take on the super strong properties of the original bar. This secondary short story ended with something along the lines that all metal becomes welded to the original bar and no metal can ever be formed into something useful ever again. This is a subject for another (unwritten) 'story-identification' question but hopefully answers to one will help find the other.     I would love to read this story and anthology again, and though I have chased suggested story questions on this stack, I am yet to find a similar question.


I saw a question on Stack Overflow and it's about Java. The post had a number of tags but not the important one, so the source code of that question looks as ugly as plaintext because the syntax highlighting was not working.  I tried to add java to the tags of that question, but I got an error  Your edit summary must be at least 10 characters   Can't we add missed tags for a question without adding anything to the body?

This has always annoyed the hell out of me, because sometimes I'm just fixing a 1 or 2 character typo that made the title harder to read, and the best summary is "typo", and the edit is obvious if you look at it.  But then I have to go and write a summary like "typo in the title fixed by me" instead of just "typo".  I realize this isn't a big deal, but why is it there at all? It's kind of annoying and serves no immediately obvious purpose given how extensive and thorough the edit viewing system is in the first place-- it's very clear what edit was made.  I'd say a char-min of 4 is better, personally.  Incidentally, this only applies to those who do not have full edit privileges. Otherwise there is no min.


I am in Indonesia, in Labuan Bajo (Flores) next to the Komodo national park, & I have been told it's possible to go to Lombok by bus & ferry.

I am in Indonesia and been told it's possible to go from Lombok to Labuan Bajo (Flores) by bus and ferry.  I am NOT interested in doing this by any other mean (ie. plane or sailing trip).  How does this actually work?


I've already enchanted all of my gear except for the knights armor and the spoon (which I don't have yet, how do you get the spoon anyways?).  The only places I haven't really discovered yet are: right door of the desert fortress, the big empty room with a chest all the way up some plateau, the spikes room in the castle, hell and the developer. Unless theres a place somewhere hidden, I don't know where to get more chocolate bars.

I've ran out of chocolate bars and didn't realize I could enchant my giant spoon and knight's armor. Is there any way to get more reliably?


everyone knows about bash vulnerability "CVE-2014-6271", I'm trying to update bash using below command.  apt-get update && apt-get install --only-upgrade bash   but i'm getting bash is already newest version.  Reading state information... Done bash is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 47 not upgraded.   and its still vulnerable for "CVE-2014-6271".

Recently, there have been news going around regarding "CVE-2014-6271" (See ), which is a vulnerability in Bash. How do I know if I am affected by this, how can I fix it, and why should I care?  This is designed as a canonical answer for this vulnerability, due to its scope and severity.


I'm wondering if the space $$S=\left\{f\in C^{\infty}([0,1])\ \ :\ \ f(0)=0\bigwedge f(1)=1\bigwedge\forall n\in\mathbb{N},\ f^{(n)}(0)=f^{(n)}(1)=0\right\}$$ contains an element $f_0$ such that $f_0^{(n)}$ has at most $n+1$ roots for all $n\in\mathbb{N}_0$.  Intuitively I'm somewhat inclined to think it's false. Do anyone know if this holds, or how I should go on about finding out?  If $f_0^{(n)}$ has $n+1$ roots, then by the mean value theorem $f_0^{(n+1)}$ has $n$ distinct roots in the interior of the support in addition to the boundary points being roots. Hence by induction $f_0^{(n)}$ must have $n+1$ roots for all $n\in\mathbb{N}$.  As to whether the lower bound is non-strict, I think maybe the way to go is to assume that $(a_i)_{i\in\mathbb{N}}$ is a sequence with $a_i \in S$ and $a_i^{(i)}$ having at most $i+1$ roots. Because if those properties imply that not all derivatives of $a_i$ remain bounded as $i\to\infty$, then no such sequence can have an element of $S$ as limit, and so the lower bound must be strict.   I made some numerically experiments with linear programs which indicated the existence of such a sequence where also $\sup_x a_i^{(1)}(x)<2$. So several derivatives must be considered simultaneously.

Let $f\in C^{\infty}(\mathbb{R},\mathbb{R})$ such that $f(x)=0$ on $\mathbb{R}$\ $(-1,1)$. Prove that there exists $n\in\mathbb{N}$ such that $f^{(n)}$ has at least n+1 zeros on $(-1,1)$  My attempt :   Assume $f$ is strictly positive  (if not n=0 works). Let $Z(f^{(n)})$ the number of zeros of $f^{(n)}$ on $(-1,1)$. Then we have: $$ \forall n\in\mathbb{N}:\;f^{(n)}(-1)=f^{(n)}(1)=0 $$ so that iterating the Rolle theorem to the successive derivatives of f we have  $$  \;Z(f^{(k+1)}) \geq Z(f^{(k)}) +1 $$ thus, by induction : $$ \forall n\in\mathbb{N}: \;Z(f^{(n+1)}) \geq Z(f^{(n)}) +1 $$ Therefore, $$ Z(f^{(n)}) \geq n $$ How can I find an another zero ?   I'm still looking for an another proof which does not use the lemma ..,  Thank you in advance.


Let $\Bbb F_{p^{n}}$ be the field of order $p^{n}$. Define a map $\phi: \Bbb F_{p^{n}}\to\Bbb F_{p^{n}}$ by $x \mapsto x^{p} -x$. My question is what is the order of im$(\phi)$?  I already know Frobenius automorphism $\sigma: \Bbb F_{p^{n}}\to\Bbb F_{p^{n}}$ via $x \mapsto x^{p}$ has order $n$. But it seems that any work with $\sigma$ does not involve $\phi$.  Any help would be much appreciated.

Consider the map $\varphi:\mathbb{F}_{p^{n}} \rightarrow \mathbb{F}_{p^{n}}$ defined by $x \mapsto x^{p}-x$. Since $(a+b)^{p}= a^{p}+b^{p}$ for all $a,b \in \mathbb{F}_{p^{n}}$ we have that $\varphi$ is a homomorphism. An element of $\mathbb{F}_{p^{n}}$ can be written in the form $a^{p}-a$ iff it is in Im$(\varphi)$, so it suffices to find $|$Im$(\varphi)|$, which is equal to $\mathbb{F}_{p^{n}}/K$ where $K=$ker$\varphi=\{a \in \mathbb{F}_{p^{n}} : a^{p}-a = 0\}$. So in particular, if $a \in$ ker$\varphi$ then $a$ is a root of the polynomial $x^{p}-x$ which is a separable polynomial so has precisely $p$ roots. Since $a^{p}=a$ for all $a \in \mathbb{F}_{p} \subseteq \mathbb{F}_{p^{n}}$, which is all $p$ of the roots, we have $|$ker$\varphi| = p$. Hence $|$Im$(\varphi)|=p^{n-1}$ so this is the number of such elements.  I am pretty sure this works, but is there an easier or shorter way?


This surely is not a priority now but I really miss the fanciful red color for the 'status-' tags and other mod-only tags.  Can we have the color on the android app?

In the website some Meta tags are coloured differently. I think this should be replicated on the android app.    Thinking about it I think the required meta tags, feature-request, support, discussion and bug should also be highlighted in some way, as they are on the desktop version.


I found the following post:    that contains code in code (because there are 2 scroll bars in the same main window).  But if I access the following URL:  I can see that the preview looks different.  Probably view & preview must show the same thing.  The usage that generated that strange view is bizarre, but I could find it useful in some other particular situations (to simulate something like block collapsing).

See . When published, the markdown does not render the same way it does in preview for edit mode. The numbered list does not continue when published, but appears to continue in preview. Moreover, the OP actually typed 2, but it still rendered as 1 which is puzzling.    Published        Editor Preview


When I want to compare two floating points values. I get strange results.  My example compiled with x86_64-w64-mingw32-g++ test.c -mfpmath=387:  #include "math.h" #include "stdio.h" int main(int argc, char **args) {      double t1 = atof("999990") * 1e-9;     double t2 = atof("999990") * 1e-9;     printf("1) Compare of two variables \"t1 != t2\": ");     if (t1 != t2) {         printf("Not Equal\n");     }     else {         printf("Equal\n");  //This is taken     }     printf("2) Compare of Variable with calculated value \"t1 != atof(\"999990\") * 1e-9\": ");     if (t1 != atof("999990") * 1e-9) {         printf("Not Equal\n");  //This is taken     }     else {         printf("Equal\n");     }     printf("3) Compare of Variable with casted calculated value \"t1 != (double)(atof(\"999990\") * 1e-9)\": ");     if (t1 != (double)(atof("999990") * 1e-9)) {         printf("Not Equal\n");  //This is taken??     }     else {         printf("Equal\n");     }     return 0; }   First comparison: OK  Second comparison: OK (assuming right term is a 80Bit precision)  Why evaluates the third comparison to unequal? Why is the cast to double not recognised? Why is the result of the comparison different than the first case?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I have a binary dependent variable and 18 independent variables which I want to use as regressors in a logistic regression. Prior to that, I want to reduce the dimensionality of the data set to shield my model against overfitting. Which dimensionality reduction technique do you recommend me given that 8 regressors are categorical, 1 is ordinal scaled, 9 are count variables and 1 is interval scaled? The size of the data set is roughly 50000. I'm working with RStudio.

I have some variables and I want to reduce their number for further analysis. I initially thought of combining them using factor analysis. But since the variables are of all kinds (rating, count, ordinal, continuous dollar amount) I am thinking about using CATPCA for it. However, I have some questions about the technique -   Is CATPCA the right approach or Latent Class Factor Analysis would be the better one? By using the different kinds of variables together - how will the object scores be interpreted? For example - The rating question is on a 10 point scale but the dollar amount ranges from 0 to 1000s, so what will the object score obtained after CATPCA represent? And is it comparable to the Factor Score obtained from traditional PCA? For ordinal variables - Do all of them need to be in the same form, e.g. 1 meaning lowest and 10 meaning highest? Or can they be used in whatever form they are? Is it good to categorize the count and continuous variables based on their distribution and then treat then as ordinal/categorical variables?   I would highly appreciate any help you can provide!


Can anyone give an mathematical elaboration of the following statement:     Quantization is a functor carrying the category of Hilbert space and linear maps to that of Symplectic manifolds satisfying some conditions specified by laws of Physics.

Imagine you're teaching a first course on quantum mechanics in which your students are well-versed in classical mechanics, but have never seen any quantum before.  How would you motivate the subject and convince your students that in fact classical mechanics cannot explain the real world and that quantum mechanics, given your knowledge of classical mechanics, is the most obvious alternative to try?  If you sit down and think about it, the idea that the state of a system, instead of being specified by the finitely many particles' position and momentum, is now described by an element of some abstract (rigged) Hilbert space and that the observables correspond to self-adjoint operators on the space of states is not at all obvious.  Why should this be the case, or at least, why might we expect this to be the case?   Then there is the issue of measurement which is even more difficult to motivate.  In the usual formulation of quantum mechanics, we assume that, given a state $|\psi \rangle$ and an observable $A$, the probability of measuring a value between $a$ and $a+da$ is given by $|\langle a|\psi \rangle |^2da$ (and furthermore, if $a$ is not an eigenvalue of $A$, then the probability of measuring a value in this interval is $0$).  How would you convince your students that this had to be the case?  I have thought about this question of motivation for a couple of years now, and so far, the only answers I've come up with are incomplete, not entirely satisfactory, and seem to be much more non-trivial than I feel they should be.  So, what do you guys think?  Can you motivate the usual formulation of quantum mechanics using only classical mechanics and minimal appeal to experimental results?  Note that, at some point, you will have to make reference to experiment.  After all, this is the reason why we needed to develop quantum mechanics.  In principle, we could just say "The Born Rule is true because its experimentally verified.", but I find this particularly unsatisfying.  I think we can do better.  Thus, I would ask that when you do invoke the results of an experiment, you do so to only justify fundamental truths, by which I mean something that can not itself just be explained in terms of more theory.  You might say that my conjecture is that the Born Rule is not a fundamental truth in this sense, but can instead be explained by more fundamental theory, which itself is justified via experiment.  Edit:  To clarify, I will try to make use of a much simpler example.  In an ideal gas, if you fix the volume, then the temperature is proportional to pressure.  So we may ask "Why?".  You could say "Well, because experiment.", or alternatively you could say "It is a trivial corollary of the ideal gas law.".  If you choose the latter, you can then ask why that is true.  Once again, you can just say "Because experiment." or you could try to prove it using more fundamental physical truths (using the kinetic theory of gases, for example).  The objective, then, is to come up with the most fundamental physical truths, prove everything else we know in terms of those, and then verify the fundamental physical truths via experiment.  And in this particular case, the objective is to do this with quantum mechanics.


What are the two sided maximal ideals of $M_3 (\mathbb {Z})$?  Is the quotient by a maximal ideal a field in case of noncommutative rings?

What are the left and right ideals of matrix ring? How about the two sided ideals?


Let's say I have a plaintext, the corresponding ciphertext encrypted using AES-XTS, and the initialization vectors. Is there any way - not brute force, of course - to compute the key?  Even if there's no known way, feel free to share articles on the subject

I have a file, which was encrypted with AES-128 in ECB mode. I know the format of the original file and know that all files in this format have the same headers. So, I have an encrypted block and the original block.  Can I get the encryption key, using this information?


Is there a way to save the file listing from a  Windows search to a text file?  I have had to search from My Computer over 6 drives for a file spec. I can't believe that there is no way to save the results to a file, or is there?

In Windows 7, is there a way to get a list the files returned by the  (AQS)?  Here is an example query:  owner:bob type:image   I want the list of files returned by that query in a text document. Can I use AQS from the command line?


How do I create this effect in Photoshop?  It appears to be something dripping downwards and is sourced directly from the V-Sauce3's youtube channel.     Could someone let me know? Thanks!

Basically I have been using the Pen Tool to create cloud shapes similar to the image below. I feel it can be a bit time consuming. Isn't there any way I can increase my workflow of making such shapes using another approach or a plugin (not too expensive)?


take a look at this example:   let my_array = [1,2,4,5,6,7,8]    test = my_array.map(element=>{     if(element!==1){         return element     } })   console.log(test)    why map() function always return something if the statement does not match? I know map function iterate over the indexes of array. but why returns null? we said return only if the statement is true. how we can avoid null in return of map()? update: I needed combination of map() and filter(): let my_array = [1, 2, 4, 5, 6, 7, 8] test = my_array   .filter(element => element !== 1)   .map(element => element * 2);  console.log(test)

I would like to filter an array of items by using the map() function. Here is a code snippet:  var filteredItems = items.map(function(item) {     if( ...some condition... )     {         return item;     } });   The problem is that filtered out items still uses space in the array and I would like to completely wipe them out.  Any idea?  EDIT: Thanks, I forgot about filter(), what I wanted is actually a filter() then a map().  EDIT2: Thanks for pointing that map() and filter() are not implemented in all browsers, although my specific code was not intended to run in a browser.


when i press the call driver button from the rider app. it shows the notifaction at driver app but it crashes because it gives error of invoking a nullpointer error.  on a null object reference error comes at this line  (JSONObject jsonObject = new JSONObject(response.body().toString());)   here is my CustomerCall class  private void getDirection(double lat, double lng) {     String requestAPI = null;     try{          requestAPI = "https://maps.googleapis.com/map/api/directions/json?"+                 "mode=driving&"+                 "transit_routing_preference=less_driving&"+                 "origin="+ Common.mLastLocation.getLatitude()+","+Common.mLastLocation.getLongitude()+"&"+                 "destination="+lat+","+lng+"&"+                 "key="+getResources().getString(R.string.google_direction_api);          Log.d( "Sunny",requestAPI ); //print url for debug          mService.getPath( requestAPI )                 .enqueue( new Callback<String>() {                     @Override                     public void onResponse(Call<String> call, Response<String> response) {                              try {                                 JSONObject jsonObject = new JSONObject(response.body().toString());                                 JSONArray routes = jsonObject.getJSONArray("routes");                                  //after get routes,just get 1st element route                                 JSONObject object = routes.getJSONObject(0);                                  //after get 1st element, we need array with name "legs"                                 JSONArray legs = object.getJSONArray("legs");                                  //and get 1st element of legs array                                 JSONObject legsObject = legs.getJSONObject(0);                                  //Now get Distance                                 JSONObject distance = legsObject.getJSONObject("distance");                                 txtDistance.setText(distance.getString("text"));                                  //get time                                 JSONObject time = legsObject.getJSONObject("duration");                                 txtTime.setText(time.getString("text"));                                  //get address                                 String address = legsObject.getString("end_address");                                 txtAddress.setText(address);                               } catch (JSONException e) {                                 e.printStackTrace();                             }                         }                        @Override                     public void onFailure(Call<String> call, Throwable t) {                         Toast.makeText( CustomerCall.this, ""+t.getMessage(), Toast.LENGTH_SHORT ).show();                      }                } );      }catch (Exception e)     {         e.printStackTrace();     } }   Logcat Error here  E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.shk.callingloader, PID: 12668 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.toString()' on a null object reference     at com.example.shk.callingloader.CustomerCall$1.onResponse(CustomerCall.java:90)     at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:71)     at android.os.Handler.handleCallback(Handler.java:790)     at android.os.Handler.dispatchMessage(Handler.java:99)     at android.os.Looper.loop(Looper.java:164)     at android.app.ActivityThread.main(ActivityThread.java:7000)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I was playing minecraft with my brother and his friend. The friend placed command blocks that @kill players infinitely; is there a way to stop this happening? I have tried the commandblockoutput command but it doesn't work.

I set a command block to /tp. It was supposed to activate only if you had 0 time left, and to activate the command block with a hopper clock to keep giving it power.   But it is not checking if you have 0 time left, so it keeps teleporting me. I can't get close enough to the command block to break it, so I'm stuck in a neverending teleport loop.  Any ideas?


The proof in my textbook says:  Let $B_1$ be a basis of $ n $ vectors and $ B_2$ be any other basis of $V$.  (a)Because $ B_1$ is a basis and $B_2 $ is linearly independent, $B_2 $ has no more than n vectors.  (b)Because B$_2$ is a basis and $ B_1$ is linearly independent, $B_2$ has at least $n$ vectors. So $B_2$ has exactly $n $ vectors.  I understand (a) because I understand that if a vector space $V$ has a basis $ B = {b_1,...,b_n} $ then any set in $ V$ containing more than $n$ vectors must be linearly dependent.  But I don't understand the logic of (b).   SOS!

Prove that any two bases of a finite dimensional vector space must have the same number of elements.  By considering the following two bases  $$S_1 = \{ \alpha_1, \alpha_2 , \ldots, \alpha_n \},$$  $$S_2 = \{ \beta_1, \beta_2, \ldots, \beta_m \},$$  how do I show that $m = n$?  Hints to get started. Thanks very much.


when I update using 'apt-get update' on ubuntu-14.04, I got the following error,  W: GPG error: http://packages.osrfoundation.org trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 67170598AF249743   I've tried following command given in some forum  apt-key adv --keyserver keyserver.ubuntu.com --recv-key 67170598AF249743   the output is as follows  Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.XI2D9gTkMc --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --keyserver-options http-proxy=http://202.141.80.80:3128 --recv-key 67170598AF249743 gpg: requesting key AF249743 from hkp server keyserver.ubuntu.com gpgkeys: key 67170598AF249743 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0   and I've tried   gpg --keyserver keyserver.ubuntu.com --recv-key 67170598AF249743   the output is  gpg: requesting key AF249743 from hkp server keyserver.ubuntu.com gpgkeys: key 67170598AF249743 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0   with command gpg -a --export 67170598AF249743 | sudo apt-key add -, I got the following result  gpg: WARNING: nothing exported gpg: no valid OpenPGP data found.   and still I get the GPG error same as above, can anyone suggest me a solution?

when I update using apt-get update on Beaglebone black, I got the following error,  W: GPG error: http://repos.rcn-ee.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D284E608A4C46402   I've tried following command given in some forum  $ apt-key adv --keyserver keyserver.ubuntu.com --recv-key D284E608A4C46402 Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --homedir /tmp/tmp.YlaPkjE1g4 --no-auto-check-trustdb --trust-model always --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv-key D284E608A4C46402 gpg: requesting key A4C46402 from hkp server keyserver.ubuntu.com gpgkeys: key D284E608A4C46402 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0   and I've tried  $ gpg --keyserver keyserver.ubuntu.com --recv-key D284E608A4C46402' gpg: requesting key A4C46402 from hkp server keyserver.ubuntu.com gpgkeys: key D284E608A4C46402 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0  $ gpg -a --export D284E608A4C46402 | sudo apt-key add - gpg: WARNING: nothing exported gpg: no valid OpenPGP data found   I'm behind proxy, and configured /etc/apt/apt.conf and /etc/environment files and aswell exported the proxy setting in terminal, pinging any site from terminal is working.   and still I get the GPG error same as above, can anyone suggest me a solution?


When making similar (wheat) flatbreads of many types (from different cultures e.g. chapati and pita), it is desirable for it to puff up like a balloon so that a pocket forms on the inside. Presumably, this happens because steam forms on the inside while the outside is cooked enough to hold it in. How can I make this happen reliably most of the time? What factors does this depend on? The dough hydration, heat, the thickness of the dough, etc.? Does the optimal technique differ between unleavened, chemically leavened, or yeast-leavened breads?

I have the opposite problem as Amir's question about . Whenever I make pita, it's nice and thick and fluffy, but the pocket is small or nonexistent. I would like to use my pita for sandwiches, so the pocket part is important.  Normally when I make pita, I get a pocket forming on one side of the bread, but the other side stays flat. I end up with a lopsided pita that has a pocket too small to stuff anything into. Every once in a while, I get one with a perfect pocket that evenly puffs up the whole pita, but I don't know why it happens sometimes and not others. Could this be caused by uneven heat in my oven? Or is there something about the technique of rolling out the dough that I'm not doing consistently?


Many times when I try to edit an answer with things like "Improved formatting" I am prohibited from doing so due to the "Your edit must be at least X characters" prompt. I understand why a rule like that exists on most SE sites. However on some sites like codegolf.stackexchange.com answers are, by nature, hardly any amount of characters long.   This answer, for example, is very small:   The headline format is not within the regular formatting of the site (Code language and byte count should be bolded with the preceding #-operator.  But I can't edit the post because just making the change does not change enough characters, and I don't want to add random characters just to make the edit do-able (though that is something I see done frequently to bypass this 'rule').  Perhaps the "at least X characters" rule should have a dynamic X based on original post length. If the answer itself is only 30 characters, maybe the the 'X' should be 5; but if the answer is 200 characters then X can be 10 or whatever it is.  What do you guys think?

On Stack Overflow, there was a question with an incorrectly formatted list, which lacked a newline before it and thus came out like this: 1. Hello 2. Something else 3. Goodbye  I changed it to the right formatting by inserting a newline:   Hello Something else Goodbye   And I got the "Edits must be at least 6 characters" error message. Is there an OK way to trick this rule?


Through the following code, I am updating the data which is already stored in the database.  But when I click on my update button it's showing the following error:     "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 're thinking a few times especially during the execution stage where things don't' at line 1".   I am unaware about why this error is showing only when there is apostrophe in my content(' or '). It is showing error for those words which has apostrophe like don't, you're, etc., during Inserting it is not showing but during updating,it is showing.  if(isset($_GET['edit'])){  $edit_id = $_GET['edit'];  $edit_query = "select * from blogs where blog_id= '$edit_id' ";  $run_edit = mysql_query($edit_query)or die(mysql_error());   while ($edit_row=mysql_fetch_array($run_edit)){       $blog_id = $edit_row['blog_id'];     $blog_title = $edit_row['blog_title'];     $blog_author = $edit_row['blog_author'];     $blog_image = $edit_row['blog_image'];     $blog_content = $edit_row['blog_content']; } } ?>  <form method="post" action="edit_blog.php?edit_form=<?php echo $edit_id; ?>" enctype="multipart/form-data">

Edit The Blog Here

         Blog Title:	         <input type="text" name="title" size="30" value="<?php echo $blog_title; ?>">

         Blog Author:	         <input type="text" name="author" size="30"value="<?php echo $blog_author; ?>">

         Blog Image:	                  <input type="file" name="image" >         <img src="../imaged/<?php echo $blog_image;?>" width="100" height="100">

         Blog Content:	         <textarea name="content" cols="30" rows="15"><?php echo $blog_content; ?></textarea>

         <input type="submit" name="update" value="Update Now">

  </form>       <?php  if(isset($_POST['update'])){  $update_id = $_GET['edit_form']; $blog_title1 = $_POST['title'];   $blog_date1 = date('y-m-d');   $blog_author1 = $_POST['author'];   $blog_content1 = $_POST['content'];   $blog_image1= $_FILES['image']['name'];   $image_tmp= $_FILES['image']['tmp_name'];  if($blog_title1=='' or $blog_author1=='' or  $blog_content1=='' or $blog_image1==''){  echo ""; exit(); }  else {   move_uploaded_file($image_tmp,"../imaged/$blog_image1");      $update_query = "update blogs SET blog_title='$blog_title1',blog_date='$blog_date1',blog_author='$blog_author1',blog_image='$blog_image1',blog_content='$blog_content1' where blog_id='$update_id' ";      if(mysql_query($update_query) or die(mysql_error())){      echo "";      echo "";      }     }  } ?>

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?


I have Website with product comparasion. Also I am thinking what to do with my titles.  4 product comparasion: Apple iPhone 6S Plus vs Samsung galaxy S7 Edge vs Microsoft Lumia 820 XL DTE SIM DUAL vs Xiaomi Redmi 1S – Compare – Example.com 2 product comparasion: Apple iPhone 6S Plus vs Samsung galaxy S7 Edge – Compare – Example.com (Facebook displays 110 characters while sharing on Fan page) 3 product comparasion: Apple iPhone 6S Plus vs Samsung galaxy S7 Edge vs Microsoft Lumia 820 XL DTE SIM DUAL – Compare – Example.com   These are long titles, Facebook wraps it araound 110. Search engines display up to 70~75 and add "..." dots.  Any ideas for these long titles? Informations what to do? (titles goes up to 150~170)  If I cut the title characters, should I add on my page  and put full in the description (~160 characters)?  Thanks!

How long should my text within my <title></title> tags really be?  I know Google cuts it off at some point but when?    When I used IIS7's SEO Toolkit 1.0 I get error stating my title should be under 65 characters.  I have a book by Bruce Clay that states I should use from 62-70 characters and roughly 9 +/- 3 words.  I also have used SenSEO's Firefox Add-on and it states I should use a max of 65 characters or roughly 15 words.  What is the max really?  I have 2 sources saying 65 and 1 saying 72 but Bruce Clay is generally kept in high regard.


I want to return top 10 records from each section in one query. Can anyone help with how to do it?  Section is one of the columns in the table.  Database is SQL Server 2005. I want to return the top 10 by date entered.  Sections are business, local, and feature.  For one particular date I want only the top (10) business rows (most recent entry), the top (10) local rows, and the top (10) features.


If modern computers are universal turing machines and C language is turing complete, theoretically we could calculate and simulate every problem in the universe then theoritically we can simulate whole universe with using modern computer which has infinite size of ram and C ?  I have searched all topics but didn't find enough answer for that question.

Here is an idea: As human kind we discovered many laws, formulas, events, etc. in our surrounding environment.here is a way to discover the unknowns :   Now if we simulate a virtual world with our knowledge in computers we expect it to work, because we guess that we know all of it. If a bug occurs in the simulation or something acts differently from the expected in the real world, that may tell us that there is something new; a thing (law, formula, ...) that we didn't know, which causes that bug or that anomaly.  For examples imagine that we created a virtual simulation for motion dynamics and we didn't add the friction to our simulation. Everything in the simulation will work fine but in a different manner. So if we hadn't discovered friction yet, would it help us to think about if there is something we didn't add? Or if there is something we don't know?       But can we simulate the whole universe, everything we know, in one simulation? I know it will require a deadly high computational power. Something like what they did for DNA; two years of computation to analyse their pattern. can we simulate everything we know to create a virtual universe to compare it to our real universe?


This is the common impression.  But, is it just a rule of thumb and correct only in some wavelength region or does it hold universally?

I read a book on the wave property of light where the author mentioned that the electric field, instead of magnetic field, dominates the light property. I don't understand why.  In Maxwell's theory, a light field has an electric and magnetic field at the same time and they are perpendicular. Also, in some books, where they consider the polarization, they only use the electric field as example. For example, if the vibration of the electric field is up and down,  it cannot go through a polarizer which orients 90 degree to the vibration direction of the field, so no light goes through the polarizer. But what happened to the magnetic field? The magnetic field is perpendicular to the electric field, so in this case, the magnetic field should pass the polarizer, and we should have outgoing light -- but we don't. Why is this so?


I wanted to prove $(Ma)\times(Mb)=(\det M)(M^{-1})^T(a\times b)$ where the formula could be found here  However, I had a hard time counting the index, and I was wondering if there's any easier way to prove it.

How can one prove the following identity of the cross product?  $$(M a)\times (M b)=\det(M) (M^{\rm T})^{-1}(a\times b)$$  $a$ and $b$ are 3-vectors, and $M$ is an invertible real $3 \times 3$ matrix.


I have torn down a crappy Antec Neo HE power supply that would turn on randomly only. It's rated 430W, amongst these 3.3V/22A, 5V/14A, 3 x 12V/16A.  I'm planning to use it for parts in a home made power supply project. There is an unidentified transformer (marked VRL35W015 on its top, SBI 4.2 E150436 C on its side) which I'd like to know how I can check its features, e.g. frequency range, max current, voltage and whatnot. The SBI 4.2 marker lead me to a  that does unfortunately not publish the specification for that transformer type.  Apparently the transformer has two primary and two secondary windings. How can I check the characteristics of this transformer? Is there a typical circuitry I can build to check it out?    EDIT: Actually the only code that is specific to this transformer is VRL35W015. SBI 4.2 and E150436 seem to be reference model or something similar. There is a small transformer next to this one, both share the same SBI 4.2 and E150436 but the smaller one has a different identifier: VEE19FRC9.  This transformer also has 6 pins on the secondary, wired together in adjacent pairs on the PCB, the primary four pins, independently connected. The document pointed to by  seems to confirm, like the hinted thread, the fact that this transformer has been specifically designed for this Antec Neo HE. Not any reason to ditch this transformer, to me of course.  I will observe (frequency, voltages and apparent ratios) with my oscilloscope how the transformer behaves. This will hopefully give me basic information, which I'll further use in my "quest". Lot of fun ahead.

I am designing a 1.7 kV @ 6 mA flyback power supply. The issue I have is that it seems to be extremely difficult to find any type of high voltage flyback transformers for the design. I bought a cheap generic CRT flyback to experiment with, but being generic it has no datasheet to speak of. I assume I can derive the winding ratio easily enough, but what about the other parameters? For example, to figure out the optimum frequency can I just do a frequency sweep until I find the highest output voltage?


I'm having troubles analyzing the plots resulting from multiple linear regression. Can someone explain briefly what do these plot mean and what are the assumptions of the multplie linear regression? Thank you so much.

I used the inbuilt dataset stackloss here. I used following R code for creating the multiple regression model.  > head(stackloss)   Air.Flow Water.Temp Acid.Conc. stack.loss   1        80         27         89         42   2        80         27         88         37   3        75         25         90         37   4        62         24         87         28   5        62         22         87         18   6        62         23         87         18  > fit <- lm(stack.loss ~ .,data=stackloss) > plot(fit)   And when I plot the model, the four following graphs are displayed.      How to interpret these graphs? What are the significance of these graphs? How to use these graphs?


I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two:   $13^{100} \bmod 7$ $7^{100} \bmod 13$   I've also heard of this formula:  $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$  But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?)  Any hints or pointers in the right direction would be great.


Every time when I close and open the lid of my Laptop, Ubuntu asks for password, which is very annoying.   Can I get rid of it? I am using Ubuntu 16.04

I would like closing the laptop lid to be a no-op. How can I do that?


I recently installed Ubuntu 12.04 on my desktop. I have three monitors, and after installing, ubuntu only detected one at 1080p. I downloaded the driver from the nvidia website, but when I stop lightdm and try to run the driver, it gives me an error message:     ERROR: Unable to find the kernel source tree for the currently running   kernel.  Please make sure you have installed the kernel source files   for your kernel and that they are properly configured; on Red Hat   Linux systems, for example, be sure you have the kernel-source or   kernel-devel RPM installed.  If you know the correct kernel source   files are installed, you may specify the kernel source path with the   --kernel-source-path command line option.   I tried instead to install the driver via the terminal, with the X ppa. The installation seemed to work, but when I rebooted, my display was at 640x480 resolution, with no other options for resolution. The NVIDIA X Server settings program is there now, but when I run it, it simply tells me that I don't seem to be using their driver, and that I should run nvidia-xconfig as root. Doing so doesn't help, I simply get the same issue again. I checked the file at /etc/X11/xorg.conf, and it's an NVIDIA file (has nvidia in the header).  Does anyone know something else I can try?  EDIT: Forgot to mention, I tried installing drivers via the     Additional Drivers   GUI utility, there were two options, one of them marked     post-release updates   I tried both of them, in both cases it tried to download and install for a while, then said that there was an error, and that a description could be found at /var/log/jockey.log. Both logs were over 700 lines.

I just ordered the Nvidia GTX card. I have a dilemma, though. Should I keep using the driver which is available in "additional drivers" in Ubuntu, or should I install the driver from the Nvidia site?  So which driver is the best for me?


For the TikZ grid command, I am wondering why the leftmost line is missing from the second grid that I am drawing below when I specify a step and do not start at (0,0).  \documentclass{article} \usepackage{tikz} \begin{document}  \begin{tikzpicture}   \draw[blue] (0,0) grid[step=5mm] (3,3);   \draw[red] (4,0) grid[step=5mm] (7,3);   \draw[green!50!black, xshift=8cm]  grid[step=5mm] (3,3); \end{tikzpicture}  \smallskip \begin{tikzpicture}   \draw[blue] (0,0) grid (3,3);   \draw[red] (4,0) grid (7,3);   \draw[green!50!black, xshift=8cm]  grid (3,3); \end{tikzpicture}  \end{document}

As in , the code  \draw[step=0.5cm,color=gray] (-1,-1) grid (1,1);   gives me a nice finite 4x4 grid. But when I choose a different starting point, like  \draw[step=0.5cm,color=gray] (2,2) grid (4,4);   then the left and the bottom border of the grid disappears. What is the problem and how can I fix it so that I have all the borders? I know I can draw a rectangle there, but I assume there is some cleaner solution.


I want to insert some special characters in Google Docs. However,there are many that my browser doesn't seem to recognize. How can I get my browser to recognize them?

There are several Unicode charactes I'm just seeing as boxes. This happens in Chrome only. The Character Encoding is set to UTF-8, but Autodetection doesn't help.   Example: []  You will only see two square brackets, but actually there is the Unicode Character  in between. It's a zero-width non-breaking space.  I also put together a little . I can't see the World Joiner character, but I can see the Hair Space. (And by seeing it I actually mean I don't see it. You see?)  This also happens when people post some new style emoticons etc.  How can I fix this?  Update:  This happens everywhere (Twitter, Facebook, you name it). I'm not using special fonts or have changed something font-related on my system (Windows 7, 64 bit). Am I wrong assuming this should just work?  Update 2:  This drives me insane. There are still so many characters that are not displaying.  Example (wrapped gift): 🎁    As you can see, Chrome is not displaying the character by default. Only when I explicitly set the font to Segoe UI Symbol, it does. Why is Chrome not using the font as a fallback automatically?  How can I make Chrome recognize the Segoe UI Symbol font?


Problem background  This question is addressed to you, ♦ moderators. There is e.g. , which is full of very useful information. It's been a community wiki with more than 17k views with 51 answers.  The question is off-topic, there's nothing to discuss, but why it was deleted ? Couldn't you just lock it as you did with a several posts around ? The biggest problem is that our community can't even undelete it because it's protected by the ♦ law.  So now it's a community wiki question, which can't be seen nor even undeleted by the community.  Question  Could you undelete that question and let the community decide what to do with it? And if that is possible, could you lock that question to keep its content visible and as it is?    P.S. those reopen votes are there because of curiosity. We shall keep that question closed.

Historical locks are sometimes applied to questions.   What is a historical lock? What is the purpose of a historical lock? How are questions affected by historical locking? When is it appropriate to lock a question for historical reasons?  When is it not appropriate? How do I request a historical lock for a question? What should I do if I notice a serious problem with a historically-locked question or one of its answers?


The problem is: A group of people met and some of them (NOT all of them) shook each other hands. Prove that the number of people who shook others' hands an odd number of times is even.  My attempt:    I have already shown the cardinality of the group of people must be finite, since saying infinity is even doesn't make sense. I tried to use the method of graph theory. But I encountered a critical problem that "the member of people who shook others' hands an odd number of times" can shook hands with "the member of people who shook others' hands an even number of times".   I thought the condition was "all of them shook each other hands", which is a easy case. But this one seems harder. I cannot figure it out. Any help will be appreciated.

In a party people shake hands with one another (not necessarily everyone with everyone else).   (a) Show that 2 people shake hands the same no. of times.   (b) Show that the number of people who shake hands an odd no. of time is even.        I find this question to be very tough and I can't find a way to even start answering this. It would be great if I could get a small hint in order for me to at least start it.


I am (barely) running Ubuntu 10.10 on an ancient laptop.  I tried to install Lubuntu over it (and hopefully remove Ubuntu) by running this in the terminal – sudo apt-get install --no-install-recommends lubuntu-desktop ().   About 10 minutes of code ran in the terminal and ended with something like this: (my user name)(my PC name):$.  This is not the exact final line in the terminal, but it is close.  At this point I had no idea what to do to complete the Lubuntu installation or close the terminal window.  I tried putting in my password and this did nothing, so I rebooted.  The result was that Ubuntu came up with no sign of Lubuntu.  What did I do wrong?

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


If I buy airline tickets for a roundtrip for two people, and the second person does not show up for the first part of the roundtrip, do airlines cancel the return ticket for that person, or can that person fly the return trip only?

I'm looking to book flights from) Philadelphia (PHL) to Detroit (DTW). Direct flights are quite expensive. I noticed, in expanding a search to surrounding airports, that I can book from Allentown (ABE) to Detroit for far less, and the connection is through Philadelphia.  Can I book this flight but board in Philadelphia? I'll be traveling with carry-on luggage only, so on the return, it's obviously no problem. But would I be allowed through security and on to the plane in PHL with out having flown from Allentown?


I've been searching for a novel I read about thirty years ago. The main character can time travel in spurts for as long as his breath lasts. He decides to see the Crucifixion but is picked up by a group of other time travellers who use this event as a way of finding others of their kind.  For some reason I've been convinced this book was by Michael Elder, but I've concluded that's not so.

I lost my sci-if book collection in a flood, and I'm trying to trace down one short story from an anthology.  I remember it starting with a boy who can slip through time. He is being mentored by his future self which he doesn't recognize. Later the story plays out in the future where he's leading a group of rebels.


I'm going to be using Windows 7 for a few months on a custom built x86_64 Intel-based platform with Z97 motherboard. Being an avid linux user, I was wondering:     does Windows have any form of managed caching, like lvm-cache or bcache?   I really like this feature and would like to  set up HDD caching with an SSD with Win7. Is it possible?  @edit: I will take into consideration solutions provided via 3rd party apps, both free and paid.

I'd like to use SSD as ReadyBoost cache disk. However, ReadyBoost can work with pluggable USB drives only (AFAIK). Is there any way to avoid this limitation?


I've created table projects like so:  CREATE TABLE projects (   project_id NUMBER(10,0) GENERATED BY DEFAULT ON NULL AS IDENTITY ,   project_name VARCHAR2(75 CHAR) NOT NULL   Then I've inserted ~150,000 rows while importing data from my old MySQL table. the MySQL had existing id numbers which i need to preserve so I added the id number to the SQL during the insert. Now when I insert new rows into the oracle table, the id is a very low number. Can you tell me how to reset my counter on the project_id column to start at 150,001 so not to mess up any of my existing id numbers? essentially i need the oracle version of:  ALTER TABLE tbl AUTO_INCREMENT = 150001;   Edit: Oracle 12c now supports the identity data type, allowing an auto number primary key that does not require us to create a sequence + insert trigger.   SOLUTION: after some creative google search terms I was able to find  thread on the oracle docs site. here is the solution for changing the identity's nextval:  ALTER TABLE     projects    MODIFY  project_id  GENERATED BY DEFAULT ON NULL AS IDENTITY ( START WITH   150000);

In , I can do something like this:  ALTER SEQUENCE serial RESTART WITH 0;   Is there an Oracle equivalent?


when I right click on desktop I get the options like below.      I use to create many new gedit/ text editor documents during day work. It's very hard to save the file first and then move it to required location.    Is there a way to get new gedit/ text editor document option when I right click on desktop or in file manager?

How can I add a right-click desktop menu entry to create a text file to Gnome 3 in Ubuntu 16.04.02?


I want to delete a certain file from TimeMachine. Using "Delete all backups of..." from the gear/context menu doesn't do anything. No warning/error message appears.  What I've  is that messing with TimeMachine directly from BASH is risky; a better way is to use tmutil.   Question: is tmutil capable of deleting individual files, i.e. doing a "Delete all backups of...", but from the command line?  Context: this file I'm so keen to delete is an .exe which has been recently marked as containing a trojan by Bitdefender. I want to keep my TimeMachine backup malware free. The .exe file is unimportant because it was compiled from C#. Probably the virtual machine I used to compile it was infected.

I'm trying to delete all backups of specific items through the command line. I can accomplish this using the GUI through the following steps:    Enter Time Machine    Navigate to the file to be deleted   Right click (or click the gear icon in the finder) and choose "Delete all backups of ..."   How can I replicate this on the command line using tmutil? Especially, when using Backup Loupe to detect large files it'd be easier to use the Terminal (since I don't have to enter TimeMachine at all each time I want to delete a particular file and can navigate to it using the Finder, and then drop it onto Terminal for a command to delete it).    I was hoping I could use something like this:  sudo tmutil delete /path/to/file   however it gives me the error:     "Invalid deletion target (error 22)"`   This works fine:  sudo tmutil delete /Volume/Backups.backupdb/<machinename>   and this too:  sudo tmutil delete /Volume/Backups.backupdb/<machinename>/<specificbackup>   According to man tmutil the delete command should also be able to delete specific items.  However, I've been out of luck so far. While there are numerous answers on this site (and elsewhere) to delete specific backups with tmutil and to delete specific backup items through the GUI (using the method described above) I was unable to find any non-GUI way to delete specific backup items.


I am in the fourth year of my PhD and I am due to complete in four years. My advisor wants 5 journal papers. I have:   One published article.  Two articles under review with two different journals, one of the articles has previously been rejected 3 times.  One manuscript being checked by my advisor. Two more works-in-progress, but I seem to have reached a limbo with these  works.    Can someone tell me if my progress is bad, average or good?  When I started my PhD, I would give a lot of effort to the work. I    would keep track of how many hours I am giving to my work, would try    to make up if the amount of hours dedicated to my work is less.  Recently, for the past 3-4 months, I am unable to feel that    dedication that I felt earlier. I can see I am working way less, but    I can't find a way to make myself motivated to work faster and work    more.  I am feeling helpless. I am feeling very guilty that I am wasting my time. But when I sit with my work, things go blunt, my brain seems to stop working. I really don't know how should I get out of this phase.   I am failing to get myself motivated to work harder. The interest is dwindling. I wish I worked more hours but I am failing to do so. I want to work harder which I am not able to do now.   Please help me out here if possible.   Advisor info: I do all the work, he just checks the grammar. I do not get any technical input from him. If I talk about how low I feel he would just say, " PhD is like this, don't lose hope". The repetition of these lines does not do any good to me.

I am a third year (starting fourth year in the fall) PhD student in mathematics. I've passed all qualifying exams and am currently doing research. As far as I can tell, I am not doing poorly. I have the good fortune of having a great advisor, being in a very supportive department, and having friends and family who genuinely care about my success.   The fact is research is hard. It appears to consist primarily of staring at a problem for days and days and days without getting anywhere. Sometimes, rarely, I do figure something out and that feels wonderful, but the overwhelming majority of my time appears to be spent banging my head against a mostly figurative wall. I am not complaining about the material being hard, and I am not averse to putting in hard work, but I get frequently discouraged when I realize the vast volumes of mathematics that I yet know nothing about (and probably never will). It's very hard to quantify progress - in particular, there are too few tangible returns after too many hours worked. I find myself thinking along the lines of "Oh, if only someone actually smart were thinking about this problem they would have solved it in moments" and so on.   I've talked about this to some number of people; here is some advice I have received:   Take a day off. Putting in hours upon hours of trying things doesn't magically lead to a solution, particularly if the brain is tired and just wants to sleep. Have a hobby. Since math research doesn't exactly provide instant gratification, a hobby might provide some instead.  Talk to other graduate students. Realize that many graduate students go through this.   I'm interested to know how other folks have dealt with being discouraged as a graduate student. Does it get better with time and experience? Is this a sign that research is not for me and that I should seriously consider a life outside academia?