I wanted to start my new and also first app, and it crashes every time i hit the button to login. It tells me that there is a NullPointerException, but i have no clue why. Could someone help me? Have been looking for solutions but can't find any helping ones so far.  package com.glowchat.app;  import android.support.annotation.NonNull; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast;  import com.google.android.gms.tasks.OnCompleteListener; import com.google.android.gms.tasks.Task; import com.google.firebase.auth.AuthResult; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser;  public class LoginActivity extends AppCompatActivity {      private Button loginbtn;     private EditText email;     private EditText password;      private FirebaseAuth auth;     private FirebaseUser user;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_login);          loginbtn = (Button) findViewById(R.id.loginbtn);          loginbtn.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                  email = (EditText) findViewById(R.id.inputEmailLogin);                 password = (EditText) findViewById(R.id.inputPasswordLogin);                  String loginemail = email.getText().toString();                 String loginpassword = password.getText().toString();                  if (loginemail.isEmpty() || loginpassword.isEmpty()) {                     Toast.makeText(LoginActivity.this, "Please fill out all fields.", Toast.LENGTH_SHORT).show();                 } else {                     auth.signInWithEmailAndPassword(loginemail, loginpassword).addOnCompleteListener(LoginActivity.this, new OnCompleteListener<AuthResult>() {                         @Override                         public void onComplete(@NonNull Task<AuthResult> task) {                             if (task.isSuccessful()) {                                 Toast.makeText(LoginActivity.this, "Authentication successfull.", Toast.LENGTH_SHORT).show();                                 user = auth.getCurrentUser();                             } else {                                 Toast.makeText(LoginActivity.this, "Authentication failed. Check your input and your internet connection.", Toast.LENGTH_SHORT).show();                                 user = null;                             }                         }                     });                 }             }             });     }  }   This is what i get in the Run tab:  E/AndroidRuntime: FATAL EXCEPTION: main     Process: com.glowchat.app, PID: 29274     java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.tasks.Task com.google.firebase.auth.FirebaseAuth.signInWithEmailAndPassword(java.lang.String, java.lang.String)' on a null object reference         at com.glowchat.app.LoginActivity$1.onClick(LoginActivity.java:47)         at android.view.View.performClick(View.java:6935)         at android.widget.TextView.performClick(TextView.java:12742)         at android.view.View$PerformClick.run(View.java:26211)         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 have to find a limit (or prove it doesn't exist) for the following recurrence sequence.  $a_1 = 2; a_{n+1} = \frac{1}{2}(a_n + \frac{2}{a_n})$  Now I know, in order to find the limit, I first need to prove that the sequence is monotonic and bounded. I've made a partial table of values and concluded that the sequence is decreasing, thus to prove monotonicity, I've written down:  $ a_{n+1} < a_n  \rightarrow a_n > \sqrt{2} $  And that's all I could think of. I don't think the inequality above proves anything so I don't know how to continue. I tried to calculate limit of the sequence by using limits of elements as follows:  $ \lim a_{n+1} = \frac{1}{2}(\lim a_n + \lim \frac{2}{a_n}) = a\Rightarrow a = \sqrt{2}$  But without proving monotonicity and bounding, there's no proof the limit exists at all.  Thank you for any help in advance.

a) Let $a>0$ and the sequence $x_n$ fulfills $x_1>0$ and $x_{n+1}=\frac{1}{2}(x_n + \frac{a}{x_n})$ for $n \in \mathbb N$. Show that $x_n \rightarrow \sqrt a$ when $n\rightarrow \infty$. I have done it in two ways, but I guess I'm not allowed to use the first one and the second one is incomplete. Can someone please help me?  We already know $x_n \rightarrow \sqrt a$, so we do another step of the iteration and see that $x_{n+1} = \sqrt a$.  Using limit, $x_n \rightarrow x, x_{n+1} \rightarrow x$ (this is the part I think it's incomplete, don't I have to show $x_{n+1} \rightarrow x$, how?), we have that   $$x = \frac x 2 (1 + \frac a {x^2}) \Rightarrow 1 = a/x^2 \Rightarrow x = \sqrt a$$ b) Let the sequence $x_n$ be defined as $x_{n+1}= 1 + \frac 1 {x_n} (n \in \mathbb N), x_1=1$. Show that it converges and calculate its limit. "Tip: Show that sequences $x_{2n}$ and $x_{2n+1}$ monotone convergent to the limit." I didn't understand the tip, how can this help me? Does it make a difference if the number is odd or even? Thanks in advance!


Why does the boolean conditions like condition always return true ? Even if the variable reponse is equal to constants OUI or NON;          final String OUI = "O";        final String NON = "N";        String reponse = OUI;        // some code was omitted        do {         // some code was omitted         // true        boolean condition = false;         do {            System.out.println(MSG_SOL_TRONCON);            reponse = mScanner.nextLine();            // Debug            System.out.println("Reponse:" + reponse + ":fin");            /*            // Boucle infinie, problème avec la condition            // Infinite Loop            condition = !((reponse == NON) || (reponse == OUI));            System.out.println("Condition : " + condition);            if (condition) {                System.out.println(MSG_ERR_TRONCON);            } // if            */        } while(condition);      } while (reponse != NON);

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


For example:           Lions are very aggressive.          I don't like lions.          For example:           Books are so important in my life. (I mean all books in general.)          The books were all over the floor. (I mean specific books that you and I know.)        Let's say you and I are living in New York. There is only one zoo in NY. You and I know about that zoo but we have never been there.  Should I say     Lions in the zoo are very aggressive. (Lions that are in the zoo are very aggressive)   or     The lions in the zoo are very aggressive. (The lions that are in the zoo are very aggressive)     Similarly, should I say     Students in Accounting class are smart.    or     The students in Accounting class are smart.

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


My question is as follows: Does there exist a sequence $(a_n)$ of non-negative real numbers such that $\sum_{n=1}^\infty a_n < \infty$, but for any sequence $(b_n)$ of non-negative numbers with $b_n \to \infty$, we have $\sum_{n=1}^\infty a_nb_n = \infty$? To me this seems to be asking if there is in some sense a "maximal" convergent series, as any "bigger" series diverges, where "bigger" means pointwise multiplied by some unbounded non-negative sequence. Thus my first thought to solve this was Zorn's lemma. I tried to define an order $\preceq$ on the space of all convergent non-negative sequences by saying $(x_n) \preceq (y_n)$ if there exists an unbounded sequence $(b_n)$ of non-negative numbers such that $y_n = b_nx_n$ for all $n$. But this order is not reflexive so we cannot use Zorn's lemma. I did manage to prove a weaker version, namely that if $(b_n)$ is any unbounded non-negative sequence then we can find a non-negative sequence $(a_n)$ with $\sum_{n=1}^\infty a_n < \infty$ and $\sum_{n=1}^\infty a_nb_n = \infty$, and I can easily extend it to finitely many $(b_n)$, but have not been able to extend it to infinitely many (i.e. for all unbounded sequences). Any suggestions are appreciated!

Given a real positive sequence $\{a_n\}$ such that $\sum_{i=1}^n a_i$ converges.  Prove that there exists a real sequence $\{c_n\}$ monotonically increasing to $\infty$ such that $\sum_{i=1}^\infty a_nc_n$ converges.  What I have done:  I have written $$\sum_{i=1}^{N+1}a_ic_i=c_{N+1}\sum_{i=1}^{N+1}a_i-\sum_{i=1}^N(c_{n+1}-c_n)S_n$$  and then try to prove the convergence by the Cauchy criterion. However my evaluation is still not good enough. I'm really stuck.


I have a type C multiple-entry visa for Latvia from the German consulate and have R/LV written below the remarks of my business visa. The sticker says "SCHENGENER STAATEN".   This is my first Schengen visa and I want to know that can I land in any Schengen state to start my trip? or do I have to land first in Latvia ?  Secondly is there any restriction on me traveling to other Schengen states as I got a 30 days visa.

In case, if I get a multiple-entry Schengen visa in one of the embassies in Ukraine, Kyiv - should my first trip be to the country which issued the visa?  Any there any requirements of this sort? Does this condition vary depending on embassy which issued the visa?  What are the possible consequences on not visiting that country first? Does it somehow depend on country where the embassy is (i.e. non-Schengen and not EU members)?


Everytime I use drupal hooks I always take the custom module route and call the hooks from there. I'm basically talking about all the hooks in drupal -- hook_form_alter(), hook_page_alter(), hook_menu, hook_user(), hook_nodeapi(), hook_init, etc. etc. etc. etc.  On the other hand, I have never actually delve into writing hooks inside my template.php so I was wondering: - If this is possible? - Is it going to work exactly the same as it does when called in a module? - Are all drupal functions available as well through template.php? - Are there any notable differences in code implementation? - In which scenario I would choose custom module over theme.php?  Please note any D6 and D7 difference.  Please advice. Thank you.

Theme functions are defined in the template.php but is it possible to define hook functions in there? for example There is a content type called phone-book, its add content form ID is phone-book-node, I want it to redirect to my custom page when it is submitted. so I created this function in the template.php :  function MYTHEME_form_phone_book_node_form_alter(&$form, &$form_state, $form_id) { $form_state['redirect'] = 'go/some/where'; }   but it doesn't work. I don't know if it is totally impossible to define such hook functions inside template.php or something is wrong with my code.


Due to a , I want to introduce a conditional definition that depends on whether or not \pgfversion >= 3. How can I do this?

Is there a LaTeX command for printing the versions of the currently installed packages? I need to know the installed version of the pgfplots package.


I am parsing a string for use in a Date object, and I have this following code that doesn't perform how I expected: const dob = "10-10-2010"   dob.split("-").map(parseInt)  What I expected was a return value of [10, 10, 2010] but instead I get an array with [10, NaN, NaN] What am I doing wrong? Am I using .map incorrectly, or parseInt? Why is one of the numbers correct, but not the other two?

From the :  [1,4,9].map(Math.sqrt)   will yield:  [1,2,3]   Why then does this:  ['1','2','3'].map(parseInt)   yield this:  [1, NaN, NaN]   I have tested in Firefox 3.0.1 and Chrome 0.3 and just as a disclaimer, I know this is not cross-browser functionality (no IE).  I found out that the following will accomplish the desired effect. However, it still doesn’t explain the errant behavior of parseInt.  ['1','2','3'].map(function(i){return +i;}) // returns [1,2,3]


I need to prove by induction if ${n^5 - n}$ is divisible by 5 and I have no idea how I would do it.   I am trying to prove it for several hours now, I started with ${n^5 - n} \mod  5 = 0$ but then I realized that I have no idea how to use modulo for transformations.  The next thing I tried was $(5 + n)\frac{n^5 - n}5 = \frac{(n+1)^5 - n+1}5$ but it didn't get me anywhere.  How would you do it?

So I started with a base case $n = 1$. This yields $5|0$, which is true since zero is divisible by any non zero number. I let $n = k >= 1$ and let $5|A = (k^5-k)$. Now I want to show $5|B = [(k+1)^5-(k+1)]$ is true....  After that I get lost.   I was given a supplement that provides a similar example, but that confuses me as well.   Here it is if anyone wants to take a look at it:  Prove that for all n elements of N, $27|(10n + 18n - 1)$.  Proof:  We use the method of mathematical induction. For $n = 1$, $10^1+18*1-1 = 27$.  Since $27|27$, the statement is correct in this case.  Let $n = k = 1$ and let $27|A = 10k + 18k - 1$.  We wish to show that $27|B = 10k+1 + 18(k + 1) - 1 = 10k+1 + 18k + 17$.  Consider $C = B - 10A$ ***I don't understand why A is multiplied by 10. $= (10k+1 + 18k + 17) - (10k+1 + 180k - 10)$    $= -162k + 27 = 27(-6k + 1)$.  Then $27|C$, and $B = 10A+C$. Since $27|A$ (inductive hypothesis) and $27|C$, then $B$ is the sum of two addends each divisible by $27$. By Theorem 1 (iii), $27|B$, and the proof is complete.


Let $R$ be a finite commutative ring with unity. Prove that every nonzero element of $R$ is either a unit or a zero–divisor.  Sol:   Let $a\not=0 $   Because $R $is finite then   $a^j=a$ , then $(a^j -a )=0$  $a (a^{j-1}-1) =0$  If $a\not=0$ then $a$ is zero divisor and $a^j a^{-1} = a^{j-2}a=1 $ so $a$ is unit   is true to prove this theorm by this way ? ,if not what is true ? Thanks  for all

Let $R$ be a finite ring with unity. Prove that every nonzero element of $R$ is either a unit or a zero-divisor.


I've read the post  and whilst it does contain a lot of useful information, it doesn't address my question about a drawing to be use for breadboards.  As I progress through learning EE (with help from the Arduino), I’m finding that creating circuit diagrams is becoming a little awkward, and I’m not sure what is the ‘right’ way of doing this to make it better/clearer.   I create circuit diagrams, then load up breadboards using the diagram as a guide, so a messy diagram is really unhelpful. (I am not planning on creating circuit boards at all at the moment. This is just a hobbyist/learning process, as I play with different circuits, components etc)  Basically, I’m coming up with instances where multiple ICs are creating a LOT of cross over wires making it incredibly difficult to trace things through or easily see what connects to what.   A simple example is trying to link up an 8x8 LED Array (1088BS) to a MAX7219 Led Driver chip. The Pin I/O of each device is not helpful, and just looks like spaghetti on my drawing when I connect everything together.  I’ve currently switched to drawing each IC multiple times, so I can see the I/O in the correct order from each side. In the following drawing, the top half and bottom half of the page each only detail 2 ICs each, although 6 are drawn. (this was drawn using Visio until I learnt the right way to do it in an EE design application)   If I drew this diagram, with the ICs side by side, and the pins in the correct place, as it would be on the breadboard, it would just be an unusable mess.  What is the ‘correct’ way of drawing this kind of design?  And would the ‘correct’ way be more beneficial to me as a guide to laying out breadboards? (and later on vero-boards)  The more I think of it, the more I'm thinking that it may not be possible to achieve, and I should change my approach to the problem rather than creating yet another drawing.

There are a lot of poorly drawn schematics here. A few times people have actually asked for critiques of their schematics. This question is intended as a single repository on schematic drawing rules and guidelines can point people to. The question is  What are the rules and guidelines for drawing good schematics?     Note: This is about schematics themselves, not about the circuits they represent.


As far as I understand it, a steady/stationary/constant current is defined to have $dJ/dt=0$ (i.e., no explicit time dependence). So I would say that sinusoids cannot produce steady currents, yet google tells me that there are such things as sinusoidal steady currents. How is that possible given that such sinusoidal currents have an explicit time dependence ($sin(\omega t$))?   When I imagine a steady current, the easiest picture is of a line current that has one $J=$constant (no time dependence), which produces a constant magnetic field loop at some radius away from the line/wire. How can a time-varying sinusoid also produce a constant magnetic field? Are 'steady sinusoidal currents' instead referring to a spatially-varying sinusoid (like a constant current density, but going around in a circular loop, i.e., a magnetic dipole)?

I am in the process of completing some homework and have come across a question that says: "What is the steady-state current?" It is asking in reference to a circuit that includes two capacitors in parrallel and a DC source of 24V and an AC source given by $\epsilon = 20 \cos(120 \pi t)\ \text{V}$, where $t$ is in seconds. I assume that it is asking when the current is constant. Because naturally the current is not constant due to the AC source, would I just consider the DC source for this?


In 16.04 there was a button on the dock you could click that would minimize all open applications. Is there a similar button in 18.04?  It looked like this:

I am migrating from Unity to GNOME. One item I am missing is a "Show desktop" button (aka "minimise all windows") in the dash. How can I add this functionality to the GNOME dash (or Ubuntu dock in Ubuntu 17.10 and later), even if it means making a custom .desktop file?  (I know that I can use the Ctrl + Super + D   and that I can install , but I specifically want a button in the dash.)


$f(x) = \dfrac x {(x-3)}$; $g(x)= \dfrac {-7}{(x+7)}$   I found The domain of $(f \circ g)$ is $(- \infty, -28/3) \cup (-28/3 , -7) \cup (-7, \infty)$ which is correct.   Can someone please tell me the domain of $(g \circ f)(x)$ ? Show work if possible please.   Thanks!

Let $$f(x)= \frac{x}{x-9} \text{ and } g(x) = \frac{-6}{x+5} $$   Find the domain of $f \circ g.$    Please show the steps and substitution/algebra to the problem. Thank you.


This user . Is a moderator with this description:  Hi, I'm not really a person.  I'm a background process that helps keep this site clean!  I do things like   Randomly poke old unanswered questions every hour so they get some attention Own community questions and answers so nobody gets unnecessary reputation from them Own downvotes on spam/evil posts that get permanently deleted Own suggested edits from anonymous users Remove abandoned questions   It accepted my edit . But why?

Why does the Community user sometimes approve or reject edits? How does a machine know if my edit is valid? What does it mean if my edit was rejected by Community?     See also:


I want to create a rule using firewalld on Linux (RHEL 7) to allow ssh from a host name. I think I've got figured out how to do it using an IP address but I need to use a host name. Here is the rule I've got so far.  firewall-cmd --permanent --zone=public --add-rich-rule=' rule family="ipv4"  source address="1.2.3.4" port protocol="tcp" port="22" accept'  I need something like:  firewall-cmd --permanent --zone=public --add-rich-rule=' rule family="ipv4"  source address="host.domainname.com" port protocol="tcp" port="22" accept'  Does anyone know how this can be done?  Thank you, Mike

Is it possible to add a rule in linux firewalld to reject an entire host(not ip or ip range) ?  For example, I wish to reject all connection coming from my133y.org.  Using firewall rich language I can drop ip, but host rejection is not provided in man pages.  Example to reject ip  firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="192.168.100.4/24" drop'   when modified to :  firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="my133t.org" drop'   I got the error:  Error: INVALID_ADDR: my133t.org


temp = [{'name':'abcd3', "id":3},         {'name':'abcd', "id":1},         {'name':'abcd4', "id":4},         {'name':'abcd2', "id":2},]   How to sort temp using id.

I have a list of dictionaries and want each item to be sorted by a specific value. Take into consideration the list: [{'name':'Homer', 'age':39}, {'name':'Bart', 'age':10}]  When sorted by name, it should become: [{'name':'Bart', 'age':10}, {'name':'Homer', 'age':39}]


My app is facing some issues with some adding, subtracting, and multiplication errors when adding the same number to itself over and over. I can add numbers such as 1.5 to 1.5, but for some reason once I start using numbers such as 3.99, after a few operations of addition or subtraction, it bugs out and outputs numbers such as 19.950000000000003. I solved the problem above by measuring the length after the . then splitting the string. However now I am getting another problem, where sometimes if you start off with 9 * 3.99 or something alike, then you subtract 3.99 over and over, sometimes it results in the following chain 35.91 -> 31.92 -> 27.93 -> 23.93  This should not be happening because from 27.93 it should have went to 23.94. Could anyone help me with these problems, and maybe suggest a better way to deal with the adding/multiplication problem besides splitting the string that is displayed?

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


In Interstella, when Murph was young she discovers something with gravity and calls it a ghost. But in the end of the movie she discovers it was Cooper. I still don't understand.

In the movie Interstellar it's shown that after Cooper fell into the Black Hole, he communicates with his daughter Murph through some codes as Ghost. My doubt is how can he communicate to his daughter before he goes into space? I didn’t get the logic of that part. Can anyone please make it clear?


I have scoured other articles trying to find a way to vertically align the last column in a multirow table in the middle. Without luck, no matter what I have tried the text will not budge. The code has now gotten to a 'hacked' stage where if I remove objects the table dies (so I apologise for that!).   I've defined   Does anyone have any suggestions?  My current code is as follows:  \begin{table}[h] \newcolumntype{A}{ >{\centering\arraybackslash} m{3.5cm} } \newcolumntype{B}{ >{\centering\arraybackslash} m{5cm} } \newcolumntype{C}{ >{\centering\arraybackslash} m{1.5cm} } \newcolumntype{D}{ >{\centering\arraybackslash} m{2cm} } \begin{tabular}{|A|B|C|D|D|} \hline \textbf{Risk Description} & \textbf{Consequences} & \textbf{Severity} & \textbf{Likelihood} & \textbf{Risk} \\ \hline \hline \multirow{2}{3.5cm}{\centering High pressures at depth}&\multirow{2}{5cm}{\centering Damage to camera’s electrical system.}&\multirow{2}{1.5cm}{\centering 9}& High Risk 4 & High Risk 36 \\[2ex] \cline{4-5} & & & Low Risk 3 & Low Risk 27 \\ [2ex]\hline  \multirow{2}{3.5cm}{\centering Leaks in camera housing}&\multirow{2}{5cm}{\centering  Damage to camera’s electrical system.}&\multirow{2}{1.5cm}{\centering 9}& High Risk 4 & High Risk 36 \\[2ex] \cline{4-5} & & & Low Risk 3 & Low Risk 27 \\ [2ex]\hline  \multirow{2}{3.5cm}{\centering Poor visibility in turbid water}&\multirow{2}{5cm}{\centering Cameras are unable to see targets and video feed quality suffers.}&\multirow{2}{1.5cm}{\centering 6}& High Risk 7 & High Risk 42 \\[2ex] \cline{4-5} & & & Low Risk 3 & Low Risk 18 \\ [2ex]\hline  \end{tabular} \end{table}   I haven't used LaTeX for long, so my knowledge base for fixing this is quite limited. Thank you for helping in advance!

Unfortunatly, I have a problem with m-columns (array package) in tables with adjusted row height. Somehow in the last column (only there) the text is not centered vertically.  Check it out:    \documentclass{article} \usepackage{array}  \begin{document}  \begin{tabular}{|m{0.18cm}|m{0.18cm}|m{0.18cm}|} \hline a & b & c  \\[2ex] \hline 0 & 0 & 0  \\ \hline \end{tabular}  \end{document}


Can someone help us, we are looking to roll out a video on demand platform to provide internal staff the ability to view content.   we will need to stream to 1000 users, the video files will be 720p videos of max size typical 250MB. they will all be streaming various aspects including pre-encoded & possibly encrypted videos (with codecs supplied to end users)     we have been recommended the following hardware   Intel Xeon 3.6ghz 4 core 64GB 6x 1.2TB SAS disks & 2x 800GB SSD write intensive 4x 1g NIC’s  but are trying to find a way to calculate the concurrent user load this server would be able to provide and any recommendations to meet our requirements.

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


How is it even possible that a single photon can be isolated and "shot" through a slit? What tool or mechanism or setup allows such an incredible feat, especially since the photon has no mass?

Many documentaries regarding the double slit experiment state that they only send a single photon through the slit. How is that achieved and can it really be ensured that it is a single photon?


I have jQuery even on button click:  $('button.btn').on('click', function(form)   Sample Exising button after page load:  <button id="5" class="yellow-button btn">Odpublicznij</button>  Works perfectly to all buttons with class btn  But then onclick after ajax request it adds new button to html  content += '<button id="' + comments[i].id + '" class="green-button btn">Upublicznij</button>';  It adds new button like:  <button id="11" class="yellow-button btn">Odpublicznij</button>  And this new button doesn't run this even $('button.btn').on('click', function(form).  And I need it to have this event, not to just be here as a button that doesn't do anything

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.


I handed in my masters dissertation a few weeks ago and I’ve now discovered a referencing mistake in my literature review. A medical publication I’d been citing has had a number of updates over the years and instead of citing the earlier year (2009) I’ve cited 2018. I could kick myself. I’m very anxious about this and not sure if I should just wait it out or speak to my advisor? I had mentioned to him that I couldn’t stop re reading it (before I realised about the year thing and he told me stop it and I wish I had listened. I realise that nothing can be done to rectify it and I’m willing to accept I’ll lose marks if found but I’m worried something more serious will happen. I’m so mortified and hoped to apply for a PhD next year ( I was on track for a first) I honestly can’t believe I’ve made such a careless mistake. Marks are due out at the end of Nov.

What would you do if you have already handed in a thesis to your professor, but you printed an earlier version with a small mistake. You want to have a great grade nevertheless, but I am feeling unsure of what to do:   Would you tell him your mistake and hope that he indulgent and says "Okay, then this does not count as a mistake." Since you recognized your own mistake, he is likely to be forgiving. Or would you say nothing and hope that he won't find the mistake?


~/project$ plot 'dis_xsq_out.dat' u 1:2:3  Command 'plot' not found, but can be installed with:  sudo apt install plotutils

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


So I am trying to prove  that for every $n > 1$ there exist $n$ consecutive composite numbers  but I do not know even how to start. This is a problem in analytic number theory. Please can you help me solve this question in analytic number theory. Thank you

for n = 4, the consecutive numbers 24,25,26,27 are all composite  For the example above, I see that they are all modulo 22, such as 23=1(mod 22) and 24=2(mod 23)  How do I go about proving it? Should i use the idea above?  Please help!


In the movie version of Ender's Game, there is a scene where Col. Graff is in his office, and they show a big HUD with all sorts of data - including      28 days until the attack on the Formics   This implies a much more rapid and accelerated rate of training for Ender - it would appear that the amount of time between his arrival at Battle School and his "training" at Command School is much shorter than the 7 or so years which it is in the book. Is there a way to explain this in-universe? Why would they change this in the movie to such a radical extent? Could Ender have really be trained in this amount of time?

The book and the movie for Ender's Game each appear to work within very different timeframes.   The book started when Ender was six and appears to have continued for a span of five to seven years. In contrast, during the movie, there's a shot in which Colonel Graff views a computer screen and sees the Formic ships in earth's vicinity. I believe that this shot of the computer screen indicated that the Formics were twenty eight days away. This would mean that the entire Ender's Game movie took place within a twenty eight day timeframe.  Can anyone confirm this?


Near me, there are a couple of gyms at max level and I was wondering if there is a way to remove an allied Pokémon in those gyms and put my pokémon? Of course, without creating another account on another team, reducing prestige and then using my main account to reach the max level again.

Sometimes I will see a level 10 gym of my team. In this case, how can I join this gym?   I assume the more I fight in this gym, the higher the prestige the gym can get, but it will never allow me to join it?


Describe the maximal ideals in the ring of Gaussian Integers $\Bbb Z[i]$.  So first of all my question would be - Is it possible to write any ideal of $\Bbb Z[i]$ (which happens to be a PID) as $\langle a\rangle$ or does it have to be $\langle a + bi\rangle$ or are they the same thing?  i.e Can ANY Ideal in $Z[i]$ be written as $\langle a\rangle$ ?  Further, I am not able to continue. Please help!  Some possible references (I looked through these but to no avail):

What are the proper ideals, prime ideals, maximal ideals of $\mathbb{Z}[i]$, the ring of Gaussian integers.    Check whether $(1+i)$ is prime or maximal ideal.     Can someone help me please. I have no idea how to crack this problem. Thanks for your time.


I am sorry this is a stupid question, but I am really confused about why $2 \times 2$ matrix is not a vector, but all $2 \times 2$ matrices can be a vector space? According to the definition, the each element in a vector spaces is a vector. So, $2 \times 2$ matrix cannot be element in a vector space since it is not even a vector.

I'm sorry if this is a silly question. I'm new to the notion of bases and all the examples I've dealt with before have involved sets of vectors containing real numbers. This has led me to assume that bases, by definition, are made up of a number of $n$-tuples.  However, now I've been thinking about a basis for all $n\times n$ matrices and I keep coming back to the idea that the simplest basis would be $n^2$ matrices, each with a single $1$ in a unique position.  Is this a valid basis? Or should I be trying to get column vectors on their own somehow?


On windows I have a program that can count all the files on a hard drive and the output shows a list of file extensions and a number (which showed how many files on the drive were for example are jpg).  How do I do this in a terminal on gnu+linux?

I did a website scrape for a conversion project. I'd like to do some statistics on the types of files in there -- for instance, 400 .html files, 100 .gif, etc. What's an easy way to do this? It has to be recursive.   Edit: With the script that maxschelpzig posted, I'm having some problems due to the architecture of the site I've scraped. Some of the files are of the name *.php?blah=blah&foo=bar with various arguments, so it counts them all as unique. So the solution needs to consider *.php* to be all of the same type, so to speak.


I'm new to blender and I would like to know  if there's any way I could bake my final render, with the shadows, the bump map etc. to one single texture that includes everything that I've done.

I created a interior scene and  i don't know how to bake a texture using cycles bake.


I was just surfing questions, and I came across a question. But accidentally I clicked on downvote for that question. I immediately changed my downvote, but still, I earned a Critics badge. Can I rollback badges I earned?   As it is been tagged as a duplicate of a question I will clarify a bit more. How can we give up a badge by our own choice?

Pretty much what the title says, but I think context is needed.  I already read , by the way, but this one is not a case of one no longer fulfilling the criteria but rather, at least in my opinion, never having met the criteria in the first place.  At stackoverflow.com, I answered  about C++. I originally intended to comment on one of the existing answers (the one existing answer, technically), but either couldn't find (after three minutes) a button or link to do that, or I do not have the required privileges to comment answers yet. Thus I opted for adding my comment as an answer.  When I posted the answer, the page notified me that I have earned the "Teacher Badge" for "answering a question with rank +1 or more" (not exact wording). With it, I also got some privileges such as chat mode. However, what I did does not technically count as answering the question, as it was a comment on an existing question -- the question itself is, already, answered. For that I feel it is kinda unfair that I have earned the badge and privileges, so I'd like to ask if there is a way to un-award the badge, remove the privileges or something.  Unfortunately I'm not that self-criticizing as to downvote my own answer, and besides it is possible the site awards me with yet another badge if I did it anyway, thus adding to the irony.  Thanks in advance.


I have folders in green color when I do ls -l then they appear colored  what could be reason for this.

What do the different colours in Ubuntu's ls command mean? For example, when I type the ls command in one of my folders, I get one of the files in light green, the other (which is a folder) in blue with green highlighting.   What do those colours mean, and there is any manual about all the colours?


In the following context, which do you use and why?      Helen doesn't eat apples or bananas. She doesn't like [fruit/fruits].   I think it is fruit but I'm having a hard time explaining to myself why it isn't fruits. What is the reason?

I've always understood the plural of fruit to be fruit, not fruits.  I was looking at some marketing material and they used the word "fruits" in the following context:      A unique infusion made with ... strawberry, raspberry and cranberry fruits    In discussion with someone about this sentence, he described that the  is not necessarily always people, and could be persons. Therefore it's possible that fruits could be a legitimate plural form.  Is fruits used correctly in this context, or could it be used correctly in ANY context?


PLEASE NOTE:  No this question does not already have an answer at the link posted above. This question was closed by individuals who didn't read it, nor the comments underneath it.  I am new to hardware/electronics and am coming from a software background. I'm ashamed to say, but I've never fully understood the difference between volts and amps. If you Google "volts vs amps" you'll get a plethora of articles/links/blogs/videos that all try to explain the difference, but IMHO they actually do a really lousy job at it, and here's why:  Most analogies to volts/amps come in one of several very-similar forms:   Water flowing through a stream; or Cars traveling on a highway during rush hour etc.   Let's take the "flowing water" analogy; it is typically explained that:   Volts: the pressure of the water traveling through the stream; and Amps: how much water is traveling through the stream   The problem here (I believe) is that electricity is always traveling at a constant speed (speed of light), regardless of how much power you're generating, or regardless of the gauge size of the wire you're using. Unlike the speed of water traveling through a stream, the speed of electricity is constant and cannot be sped up or slowed down (I understand in the context of theoretical physics this is probably not true, but we're talking consumer electronics here).  With flowing water, if we increase the size of the stream (its width or depth), then not only will more water pass through any given point (volume), but the speed of the water will also increase. This is given to us by the .  So I've always had this mental hang up with trying to understand exactly what volts are, because the analogies that are always used just don't stack up.  It makes sense that amps can be changed by changing the gauge of the wire the current is traveling through; this is the same as increasing the volume of the stream; but...  To me, it doesn't make sense that volts should ever be capable of changing, because volts are essentially the speed/pressure of the water passing through the stream, but electricity can't actually speed up or slow down! This is where the analogies break down for me, and is the root of my confusion.  Can someone please help me understand how electricity can have different levels of "pressure" or "potential", which is what volts are said to be, in a way that makes sense?   Again, if electricity travels at a constant speed, and we make the wire bigger, I understand that we will get more volume/amps. But I don't understand how this will create more "pressure" since the bigger wire will not actually make the electricity speed up.

Bit of a strange question, but what is it? My physics teacher said it was kind of like a "push" that pushes electrons around the circuit. Can I have a more complex explanation? Any help is much appreciated.


Prove that there is no quadruplet of integers $(a, b, c, d)$, not all $0$, such that: $$ a^2 + b^2 = 3(c^2+d^2)$$  I would appreciate a solution for this problem or a hint please.

Prove that: $$  x^2 + y^2 = 3(z^2 + m^2)  $$ has no solutions in integer Except $0 0 0 0$


I have tried to use long double type in my program to print out more digits of pi. But it only shows 5 digits decimal.  Here is my code.  int main(int argc, char** argv) {      long double pi_18 = acos(static_cast<long double>(-1));     cout << "pi to 18:" << pi_18 << endl;      return 0; }   and this is my output:  pi to 18: 3.14159   How can I fix this problem?

In my  I was printing a double using cout that got rounded when I wasn't expecting it.  How can I make cout print a double using full precision?


Given that N is a natural number .Then I was trying to find the number of positive integral solutions of the equation    $$1!+2!+3!+4!+.....+x!=N^2$$   By hit and trial, $1$ and $3$ are obvious solutions for $x$.  But are these the only solutions and how can I find any other solutions if present ?

How to prove that the number $1!+2!+3!+...+n! \ \forall n \geq 4$ is never square?  I was told to count permutations but I cannot figure out what we are permuting.... Thanks!


I am very new to regex and learning by practice. I wrote the following regex for finding a number inside a string of characters, however, it returns nothing. Why is that?   string = "hello world & bello stack 12456";  findObj = re.match(r'[0-9]+',string,re.I);  if findObj:     print findObj.group(); else:     print "nothing matched"   Regards

What is the difference between the search() and match() functions in the ?  I've read the  (), but I never seem to remember it.  I keep having to look it up and re-learn it.  I'm hoping that someone will answer it clearly with examples so that (perhaps) it will stick in my head.  Or at least I'll have a better place to return with my question and it will take less time to re-learn it.


How do I evaluate a reduction formula for the indefinite integral of $\int \frac{x^n}{\sqrt{x^2 + a^2}}dx$ , for any positive integer n?  I have tried integration by parts, with $u=x^2$ and $\frac{dv}{dx}$ = $\frac{1}{a\sqrt{\frac{x^2}{a^2}+1}}$ but still unable to see any recurring pattern.  Can someone please guide me/show me a sample solution?

How do I derive this using reduction formula?  $$I_n=\int{\frac{x^n}{\sqrt{x^2+a^2}} dx}$$  I got $\sqrt{x^2+a^2}(x^n) - \frac{1}{n-1}(x^{n-1})\sqrt{x^2+a^2} + \frac{1}{n-1}(I_n) $ . I'm not too sure if this is correct. I would appreciate any form of help or correction to my answer. Thank you.


He rode a bicycle to work every day last month. OR He has ridden a bicycle to work every day last month.

Non-native speakers often get confused about what the various tenses  and aspects mean in English. With input from some of the folk here I've put together a diagram that I hope will provide some clarity on the matter.  I offer it as the first answer to this question. Consider it a living document. Input is welcome, and good suggestions will be  incorporated into the diagram.    Nota bene: What this is not is a discussion of whether there are  more than two tenses in English. , to which this question is not intended to supply arguments one way or the other.  Here, the aim is to provide an overview of what constructions English-speaking people use for conveying information about actions referring to past, present, and future, and to provide it first and foremost to precisely the people who are likely to use "tense" as a catch-all term in their search, rather than to linguists who know better.  Breaking News There is now an excellent ELU blog article titled  . It is highly recommended reading.


I am studying category theory for the first time, and I keep coming across the idea that sets cannot be “too big”.   For example, in the definition of a small category: A category is small if the collection of objects and the collection of arrows are sets.  My question is this; given some collection, how can I systematically decide if it is a set? And if it is not a set, how can I tell how far removed it is from a set? (In other words, what is it?)  I am familiar with Russel’s paradox, but I’m not sure how that is useful to determine whether or not something is a set.

I'm wondering whether or not there is a definite criterion for determining whether a collection of objects is a set. In the literature, I've recently encountered some obscure examples (in Riemann Surface Theory, to be precise) of naturally-arising collections of objects which are not sets.   Here is some pseudo-rigor to make the question more precise:   Let $S$ be a collection of objects. Is there some property $P$ so that $S$ is a set iff $S$ has property $P$?


With the following code:   #include <bits/stdc++.h> using namespace std; const double pi = 3.14159;  int main() {  double x; cin >> x;   cout << "A=" << pi * x * x << endl;   return 0;  }   And inputting   100.64  I get the value 31819.3, while what I want is 31819.3103   I tried using set precision but that doesn't seem to work either.  Why is this happening?


Related:     video asserts that:   A properly patched area of a tube is stronger than intact tube area Never patch a tube more than 3 times   Those are seemingly contradictory.   The video is just and example and motivation for this question. I have often seem people discard tubes with several patches, after they are punctured again.  Is it true that after some number of patches to a tube, it is better to dump the thing? How many?

Any thoughts - my spare tube that I carry in my bag currently has a dozen or so patches on it, but still works fine. I'm tempted to keep going to see how many I can get on there until it get impossible to mend.  What is the most number of patches you reckon a tube can take ?  (And I know new inner tubes are only £5 or so, but a puncture repair costs about 10p if you buy the patches and glue in bulk, so "It's cheaper to buy a new one" is not necessarily true...)


I have a list of files along with their filepaths, that I'm planning to copy into a server. Is there a way, I could figure out before I copy, which filesystem it actually would go into? assuming the disks have been partitioned and mounted.

I have an NFS share which is shared across about two other machines. I recently realized that one of the servers isn't sharing the directory and is keeping files all for itself. Is there a way to see if the NFS share is mounted in the directory I think it is in?


After e.g. do you always put a comma even if the example is only one thing? DO you write e.g., chicken soup or e.g. chicken soup?  My question refers explicitly to using just a singular example.

It seems that "e.g." is always followed by a comma but "i.e." is not. Why is that?


I'm aware of the  question from a few years back, but mine's slightly different  A user asked a question, which wasn't clear. I left a comment explaining what information we needed, and left a close vote for unclear what you're asking. Some time later, the OP came back, and edited their question with the missing information. With that information in the question, it was then clear it was a duplicate. So, I retracted my unclear close vote, and went to close as a duplicate, but it wouldn't let me!  I can understand that there's a desire for stopping people changing their mind on a close vote when the question is unchanged, as covered in the older meta question. However, I can't see why I shouldn't be able to change my close vote after the OP makes significant changes via a big edit to there question  Could it be changed so that you can change your close vote (eg unclear to duplicate) after major edits to the question?

It should be possible to change the closing reason or at least remove it.   Could remove the close vote when the user edits the post Could change the closing reason if need be   But the most useful thing is that you could change the question that you marked as duplicate. If I vote and say this question is a duplicate but I misread or the post was edited or I want to change it for whatever reason, I can't. Also, it will automatically put a comment of me saying that this question looks like a duplicate of x other post so I should be able to change the post it refers too.


I am revising for an exam and I am facing the following statement: $\frac{1}{1-p}=\sum_{k=0}^\infty {p^k}$  Unfortunately, I was not able to figure out why this is the case. May somebody of you quickly help me? I appreciate it a lot for a detailed explanation!

Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: .


This question is not specific to language/framework/platform.   I want to know (and confirm), what should happen (by default) if a user taps and holds (or clicks and hold).  This is more about basic usability and user experience.  What would a user expect to happen if the user taps(or click) and hold.  For some clarification I did read this:   The framework where I need to work on currently triggers holdstart if you hold for more than 400ms, and that in turn triggers tapcancel. I am not happy with it, thus want to know what is the more appropriate default behavior a user would expect.

Often, I find people struggle with the usage of press-and-hold gestures on mobile/web platforms. The mere thought of having a user press on a defined object and hold for an arbitrary amount of time before the product reacts seems overtly complicated and unobtrusive. My questions are:   For what use cases do press-and-hold gestures best fit? Have there been published studies with regards to press-and-hold gesture intuition? Are there more viable alternatives to this system?


Per the Monster Manual's statblock for the Otyugh (pg 248), a successful tentacle attack results in the following:     If the target is Medium or smaller, it is grappled (escape DC13) and   restrained until the grapple ends.   Does the target get a chance to do a save of some kind to avoid being grappled in the first place? I am aware that the target can use an action to escape after being grappled, but is there any way a Medium or smaller creature can avoid being grappled on a successful hit with a tentacle attack?

In 5e to escape a Grapple check, I know you roll athletics (str) or acrobatics (dex) opposed by an athletics (str) check.  In the Otyugh entry in the Monster Manual it doesn't say there's any check, instead it assigns a set DC for an "escape" (DC 13... which is a str check with a 10 assigned as the "roll").    So the question is:    Does the Otyugh actually make a roll in this instance (like the general rule) or does it have a set DC (for the specific case) OR is it just a poorly communicated version of the GENERAL rule being played out?   A little clarification on this would be AWESOME. In the event of a "specific vs general" scenario, what actually is the "escape" roll?  What modifier is applied? None?


I'm trying to understand the usage of "knew from" in the following quote:     (suddenly cleaning ladies knew from sun-dried tomatoes, suddenly hog farmers knew from creme brulee)   Source:   To me (not a native English speaker), this seems ungrammatical. I understand the meaning of phrases like "know a from b", but I'm unable to parse this in any way that makes sense. Does "knew from" has some special meaning here?

A couple of times I've seen a phrase much like "that's horrible coding — and I would know from horrible coding!" This seems extremely peculiar to me (if only because of how ungrammatical it is), and while I can guess that it's supposed to be some emphatic way to indicate the subject's authority on the matter, it's pretty unusual and I don't fully grasp it.  Unfortunately, I don't have a good verbatim example on hand, so it's possible my memory is muddling the context of the phrase slightly.  Anyway, what does this bizarre turn of phrase mean exactly and where does it come from?


Those who have the "cast close and reopen votes" privilege can cast close and reopen votes to close and reopen questions.  For those who do not, they can raise recommended closure flags to close questions, but what could they do to reopen?    I've once posted a reopen request question on Music Stack Exchange Meta in order to have a question on Music Stack Exchange to be reopened.

TL;DR: Grant 500+ rep users (except the OP) the privilege to flag a question for reopening. Currently, you can flag a question for closing, and it automatically enters the  review queue, where 3K+ users can vote to close (or to leave open) the question.  However, there is no ability to flag a closed question for reopening. A <3K user must either:  Flag for diamond moderator attention, causing more workload for the moderators. Create a meta-post on the question, requesting for the question to be reopened. ...  Feature Request Add the ability to flag a post for reopening, just as you can flag for closing. The UI of the flagging dialog for closed post could look like this:  A reopen flag would instantly bring the question into the  review queue, where 3K+ users would vote to reopen (or to leave closed), just like when a reopen vote is cast on a question. This option would be available to everybody except the OP of the question, since he can bring his question to the review queue by editing it. A reputation limit could also be added to prevent abuse, e.g., .


I'm working on a problem, and I'm stuck in the calculations of finding  $\sum\limits_{n=0}^{\infty}\frac{1}{1+n^2}$  Suggestions on how to approach this calculation? Thanks!   (Also, I used Fourier to get to this result from where we were... so using the Fourier somehow feels counter intuitive, but I might be wrong)  Thanks in advance.

This is a homework question whereby I am supposed to evaluate:  $$\sum_{n=1}^\infty \frac{1}{n^2 +1}$$  Wolfram Alpha outputs the answer as   $$\frac{1}{2}(\pi \coth(\pi) - 1)$$  But I have no idea how to get there. Tried partial fractions (by splitting into imaginary components), tried comparing with the Basel problem (turns out there's little similarities), nothing worked.


This question is NOT about access to USB or external drives.  WPS Witer and other just installed Ubuntu software can NOT open files saved on my /media directory. I keep getting the annoying message: « Could not read the contents of '/media': Permission denied ».   MY SIMPLE QUESTION REMAINS:  How can I access all files and folders on my user username/media/ directory?  I'm using Ubuntu 18.04.3 LTS.  Ubuntu's Nautilus can indeed access all files and folders in all locations. However, Ubuntu's software that I have downloaded (e.g. KRITA, WPS WRITER etc) can NOT access any file or folder on the /media directory. Thanks in advance.

I have Ubuntu 18.04 LTS installed. I inserted USB-flash to my laptop. It was automounted to /media/username/DISKLABEL and opened in Nautilus. I can read and write objects to it. How can I access it from the application, which is installed as Snap? I tried snaps of the following applications such as gedit, arduino-mhall119, organize-my-files. All them show me errors if I navigate to /media folder:    Could not read the contents of Media Error opening the directory of '/media': permission denied  Output of active Snap  is below: $ snap interfaces  | grep -v ".*-$" Slot                             Plug :browser-support                 organize-my-files :core-support                    core:core-support-plug :cups-control                    gedit :desktop                         gedit,organize-my-files :desktop-legacy                  gedit,organize-my-files :gsettings                       gedit,organize-my-files :home                            arduino-mhall119,gedit,organize-my-files :network                         arduino-mhall119,gedit,organize-my-files,pulsemixer :opengl                          organize-my-files :pulseaudio                      organize-my-files,pulsemixer :unity7                          arduino-mhall119,gedit,organize-my-files :wayland                         gedit :x11                             arduino-mhall119,organize-my-files,pulsemixer gnome-3-26-1604:gnome-3-26-1604  gedit gtk-common-themes:gtk3-themes    gedit gtk-common-themes:icon-themes    gedit gtk-common-themes:sound-themes   gedit -                                arduino-mhall119:serial-port -                                gedit:avahi-observe -                                gedit:mount-observe  Updates:  connecting mount-observe to Gedit with snap connect gedit:mount-observe does not help. it seems that we need special Snap with support of  interface.


I use a big screen 4K 43", of course the resolution 4K makes everything too small on screen.  On windows, I have a option to zoom all the desktop GUI, normally I use 150%.  Is there a way to do the same on linux? I'm using Ubuntu Studio latest version. I can change the resolution to FHD but than the things are tooooo big.  Thx for any help.

I recently installed Ubuntu 18.04 and discovered that the fractional scaling option that was in 16.04 is no longer there. 200% is too big for my display, and  didn't work for me (the options didn't change after running the command).  Is there another way to get fractional scaling?


My code:  #!/bin/bash  x=${#}  for (( a=0; a<x; ++a)); do    if [[ $1 -eq $1 ]] 2> /dev/null    then       variable[a]=${1}       shift    else       echo "The argument $1 is NOT an integer. Aborting this"       exit 1    fi done TOTAL=0 for (( a=0; a<x; ++a)); do       echo "TOTAL : ${TOTAL}"       TOTAL=$((TOTAL+variable[a])) done echo "Everything accounted to $TOTAL" exit 0   So basically it takes the arguments of the script and sums them up. If one of the arguments is not an integer, it should tell you and exit the script.  The way it is right now it doesn't tell me if one of the arguments isn't an integer, it just skips it. So giving it the arguments 123 123 123 asdt, I get the following:  vagrant@localhost vagrant]$./super.sh 123 123 123 asdt TOTAL : 0 TOTAL : 123 TOTAL : 246 TOTAL : 369 Everything accounted to 369 [07:43---------------------------------------- vagrant@localhost vagrant]$   But if I change it to this:  for (( a=0; a<x; ++a)); do    if [ $1 -eq $1 ] 2> /dev/null    then   It works and I get this:  vagrant@localhost vagrant]$./super.sh 123 123 123 asdt The argument asdt is NOT an integer. Aborting this [07:44---------------------------------------- vagrant@localhost vagrant]$   Why does that happen?

This script:  a=2 [[ "$a" -eq 2 ]] && echo yes1 [[  $a  -eq 2 ]] && echo yes2 [[   a  -eq 2 ]] && echo yes3 [[  "a" -eq 2 ]] && echo yes4   Does not work in  (and some others that do not have [[ ). Fails the last two "yes tests" in  (BusyBox ash). As I expected.  But, quite UN expectly: This happens when the arithmetic  » -eq «  is being used (and some other). Prints all the four yes in , , , ,  and .  Q's  Is this the natural side effect of "Arithmetic Expansion" being applied to labels like (a) ?. (nothing to see, move along ?)  Should (a) still be expanded as a variable when quoted: "a"?  Is this documented somewhere I haven't look into yet?  Or, Is a simple (very old) bug?  Edit  To really get you thinking, check this:  a=2; b=2  [[ "$a" -eq "$b"                 ]] && echo yes1 [[  $a  -eq "$b"                 ]] && echo yes2 [[   a  -eq "$b"                 ]] && echo yes3 [[  "a" -eq "$b"                 ]] && echo yes4 [[ "$a" -eq "$b" && "$a" == "$b" ]] && echo new1 [[  $a  -eq "$b" &&  $a  == "$b" ]] && echo new2 [[   a  -eq "$b" &&   a  == "$b" ]] && echo new3 [[  "a" -eq "$b" &&  "a" == "$b" ]] && echo new4   All yes work, only new1 and new2 do. The var a is not being expanded in new3 & 4.  That means that shells switch mode (Arithmetic -- String) in the middle of the evaluation.  This doesn't seem so obvious to me. At least, is not simple, IMO.  Note that ash does it in a different way. And also report the error.  Conclusion:  I do not know the correct answer. But I suspect (looking at so many shells doing it exactly the same way) that it is a very well known way (to developers) in which this tests should work. It should be up to us to understand the fact and adapt.  Seems that for numeric -eq the only possible 'Conditional Expression' to apply is:  exp1 -eq exp2           true if exp1 is numerically equal to exp2.   Which makes both sides of the -eq "Arithmetic expressions"  While for the == the only possible 'Conditional Expression' to apply is:  string == pattern           true if string matches pattern. ....   Which makes the left hand side an string (no expansion?) and the right hand side a pattern (which really do not apply to the test I presented as all were quoted on the right side to avoid this complexity. So, right hand side defaults (being quoted) to an string also (no arithmetic expansion here).  But maybe I am more confused than I though :-)  What do you say?


I've just changed from  +  to  and I'd like to get the functionality of the globalcitecopy option. As explained in the documentation of bibunits:     Create an entry in the global bibliography for each cite command within a bibunit. Default is to create an entry only for the local bibliography.   I've defined refsectionswith biblatex, but when trying to print the global bibliography either with \printbibliography or \bibbysection I can't get all the references cited in the whole document shown and sorted all together.  After reading the documentation of biblatex I suppose I'm skipping something, but I can't guess. How should it be done?    As @moewe pointed out, I was mixing concepts. Just using segments instead of sections solves it.  \documentclass[a4paper,titlepage,10pt,twoside,openright]{report}  \usepackage[backend=biber,style=ieee-alphabetic,natbib=true]{biblatex} \addbibresource{IEEEfull.bib} \addbibresource{IEEEexample.bib}  \usepackage{lipsum}  \begin{document}  %\begin{refsection} \begin{refsegment}  \chapter{Introduction}  \cite{IEEEexample:articledualmonths}  \section{First section}  \cite{IEEEexample:shellCTANpage}   %\printbibliography[heading=subbibliography]  \printbibliography[segment=\therefsegment,heading=subbibliography] %\end{refsection} \end{refsegment}  \section{Second section} \cite{IEEEexample:IEEEwebsite} \nocite{IEEEexample:book_typical,IEEEexample:article_typical}    \cleardoublepage  \printbibliography[heading=bibliography]  \end{document}

I currently print my references after the end of each chapter, using:  \usepackage[backend=biber,     bibencoding=utf8,     refsection=chapter,     style=numeric,      firstinits=true,     isbn=false,     doi=true,     url=false,     clearlang=true ]{biblatex}   and   \printbibliography[heading=subbibliography]   at the end of each chapter.  I would like to have also a chapter at the end of the book with all cited references. How could I do ?


If I want to write how many of something I have that uses "s" to indicate plural, I can use (s), as in "Joe had X apple(s)". But say I want to write something like "The report contains 2 entries" or "The report contains 1 entry". Since the plural of entry isn't "entrys", it seems incorrect to write entry(s). What is the proper syntax for this?

I guess “optional plural” is the correct term.  I’m referring to things like    It can be found at the following location(s). Please pick up your ticket(s).   But how do I do that to a word that ends in ‑y? Take category for example: “category(s)” doesn’t seem correct, because categorys is a misspelling.  But everything else I have tried looks ridiculous.  What’s the correct approach here?


I have this question because I am reading the section for auto_ptr. It says auto_ptr cannot be saved in a vector because of its destructive copy and assignment. I can understand it somehow and one example I can think of is something like auto_ptr ap = vec[0] will surprise me. But what if I use it cautiously and do not do this, can I store auto_ptr in a vector? Is there any deeper reason why I cannot store? Maybe the implementation of vector internally needs this assumption that elements need to be copy constructable?  Thanks.

Why is it wrong to use std::auto_ptr<> with standard containers?


I want to know that is  compatible with canon 600D. It's head will be set with 600D?

Is there a standard tripod mount?  Is it reasonable to assume that a given tripod will attach successfully to a given camera, or will I have to research my options?


The main character lives on a sparsely populated world, where everyone goes to school to become mechanics, only they have lost the knowledge of why they are learning, so they are all skilled at something they don't understand  Meanwhile, outside in the rest of the galaxy there are almost no working spaceships, and we follow a new character tasked with finding new ones to salvage she lands on the planet and ends up taking the other character with him in his ship, the guy ends up fixing his ship, I specifically remember him fixing the air conditioner on the ship. The pilot realizes that his side of the Galactic conflict now has a way to fix all of their ships and I think that's where it ends.  I remember reading the story around 2012, but it is most likely from an anthology, possibly from the 80s or 90s

I read this short sci-fi story some time ago:  The story is about an abandoned colony of military engineer corps that crash landed on a planet. They still know all about repairing equipment (they don't have any).   The other part is about the empire that is losing the knowledge about repairing the ships and equipment. One day, a ship reach the colony.


If I run ubuntu-drivers list the output is:  bcmwl-kernel-source nvidia-driver-396 nvidia-driver-390 nvidia-340   No clue what bcmwl is, but nvidia drivers 340 and 390 I have uninstalled. Why are they still displayed?

At our university we can get almost any ubuntu package installed we want, but we are not superusers ourselves (we need to request packages being installed).  With some libraries it is not always easy to know whether the package is already installed or not. Is there a simple way/command to check this?


I have installed lots of apps on my phone. For the last couple of weeks i am facing one issue. Even when i am not using internet infact even when i am not using my phone at all, a window pops up and says you have just downloaded ??mb of data!!! and because of this my battery is draining very fast. I have to charge it twice a day. I don't even know which app is accessing net,   I suspected the pulse feed reader and google+ for this. Uninstalled pulse reader but still there is problem. If i could got to know which app is that then i will just uninstall that.  Phone: HTC Desire S OS: Android 2.3.3

I have a Samsung Spica running Eclair (rooted). I've noticed on a number of occasions that inspite of the Autosync option turned off, the sync icon appears in the notification bar. By default, Gmail, Calendar & Contacts are set to sync whenever the Autosync option is turned on.  I don't use any scheduler app like Locale or Tasker.  Is there an app or some way to see which app is connecting to the Internet at any given time? Or can someone verify if this sort of behaviour of the sync icon appearing is normal?


If I'm a high-rep user on both SO and, e.g., stats.stackexchange, why not give executive rights when voting to close a question that clearly needs to be migrated? That is, no consensus needed -- once a sufficiently "experienced" user of both communities weighs in, voting can end.  (perhaps this feature does exist, and I simply haven't met the criteria yet; documentation would be helpful)  This is inspired by the analogous rights for gold badge users closing duplicates within SO.

Migration flags and votes should be removed from the close menu. Instead, along with "share, edit, close, flag" at the bottom of the question, there is a "migrate" option.  When you click this, you will always have the option to migrate to that site's Meta page.  Beyond the meta site, however, the migration options are limited to sites for which you have a user account on (and there should probably be a soft-search menu in here for our particularly eclectic users).  More importantly, whether your migration vote counts as a flag or an actual migration vote depends on your rep on the migration target site.  If you're at 3,000 or more rep on the target site, your vote counts as an actual vote.  If you're below this, it shows up in the review queue on the target site.  So for example, let's say I'm a Stack Overflow user with over 3,000 rep. I'm also a user with a DBA account with less than 3,000 rep, and a Code Review account with over 3,000 rep.  If I see a question on Stack Overflow which looks like it'd be better posted elsewhere, I can flag it for migration to DBA (if that looks right to me) (which pops it up in the review queue for other DBA users with over 3,000 rep on DBA and SO to vote in agreement with my flag), or I can vote it for migration to Code Review (if CR looks appropriate to me).  Currently, if you try to vote a question to migrate away from Stack Overflow, you are presented with the following menu:    And it doesn't matter who you are, these are the five migration options you get.  And the fact of the matter is, I know I personally shouldn't be allowed to migrate to TeX or Stats.  I don't have an account on either of these sites, nevermind having in the slightest clue what sorts of questions on are on topic there.  Meanwhile, I do have a Super User account, and I do have a DBA account, but I have exactly 101 rep on both of these sites.  I've never asked a question, posted an answer, or even so much as left a comment.  I think I only created an account on these sites because I was thinking about asking a question or I wanted to upvote someone's answer (I have a use for these sites, but not much to contribute).  Meanwhile, there are other Stack Exchange network sites that have some potential for overlap with Stack Overflow.   Android Enthusiasts Ask Different Ask Ubuntu Drupal Answers Electrical Engineering Game Development Information Security Programmers Server Fault Theoretical Computer Science Unix & Linux User Experience Webmasters WordPress Development   This list only includes graduated sites whose designs have been completed.  There are even more if we count beta sites (or graduates sites whose designs aren't yet completed, like ).  But, I don't think all of these sites should be in the list either.  , I am primarily talking about the list of migration targets being dynamically generated for each member based on which other sites they are members of.  If you don't even have an account at the target site, how can you possibly know that this question is better suited here than there?


In Quantum Leap, Sam Beckett switched into other peoples bodies and changed, or restored, or ensured history that was guided to the history as it was known in Sam's own timeline. These people seemed to be kept isolated in a lab in Sam's (their future) timeline. Once Sam did his thing as dictated by that weeks mission, he leapt out and the displaced person returned to their place in time. Since they were unaware of the decisions and actions Sam performed in their name, how did they continue the altered timeline without unraveling Sam's activities?

In the TV show Quantum Leap Sam Beckett would travel history and "right" wrongs, temporarily displacing someone native to that timeline in the process. Would the memories of what Sam did transfer to the person he displaced upon his leaping out, or would they wind up with amnesia for the time Sam was there?


We have an application which we recently upgraded and is having bad performance issues. Any ideas would be much appreciated.  The main issue is windows taking ages (minutes) to open because the initial query to fill their list boxes is taking so long. The second time a user opens the window its fine.  We would expect this to be application cacheing but we don't think so. We see similar problems using Crystal Reports and using command line SQL queries.  We have increased the RAM available to the database.  Another part of our business has a slightly different version of the same application and database and doesn't get this problem.  The time to complete a query can be 30 minutes for the first time in a session and 30 seconds for subsequent executions.

I noticed when running a SQL query it is faster the second time than the first. So my question is, in Oracle SQL Developer where can you see the statistics that explain this behaviour?


We all know that Americans say:     Sara is going to the hospital   While in the UK, they would say (and Americans would never say):     Sara is going to hospital   I'm wondering what the history of this difference is given that in AE, the usage of the "the" modifier seems extraordinarily arbitrary: Americans would say:     Sara is going to school   to mean that Sara is going to be enrolled in school. While they would say:     Sara is going to the school   to mean that Sara is going a particular school building (not enrolled).  To me this intuitively suggests some sort of lack of "personal" connection with the concept of a hospital which is not there when it comes to concepts like "school" or "church".   Now for the leap: does this perhaps have anything to do that in the US, healthcare has been a private entity (until recent occurrences), and not generally regarded as a personal right (but rather, a privilege)?  I know this is a stretch, but this could be an explanation for the "impersonal" way in which AE uses the word — unless my history is all wrong here?  No politics here, just curious about the root of this difference.

Why do British speakers omit the article in constructions like "go to hospital" or "go on holiday"? Pretty much all American speakers would rephrase those as "go to the hospital" and "go on a holiday", I think. Is there any good reason, or forgotten sense behind those words that might explain why the articles are ommitted?  Are there other common constructions other than those two that the British use that drop the article?  EDIT: I just realized per Kosmonaut's comment that Americans do much the same thing with a few nouns, so this isn't all that special.   Do grammaticists designate nouns that can have their article dropped with anything, i.e. do they have anything in common?


I just downloaded the Text Fx addon because I wanted to make a digital speedometer in an animation. I downloaded the addon as instructed and selected install inside Blender preferences. It had a caution symbol and told me that I needed to update 20 Blender 2.8x. So I updated to the newest version and it still said I needed an update. So I uninstalled it and tried installing it from a new source. This time I was not given an error but nothing new was in my add objects tab to add the text and there should have been an extra tab for text editing. So it hadn't actually installed? I am incredibly confused.

I have an Addon I'd like to use, but when I would install the .py file, theres a message on the far right saying I need to "upgrade to 2.8x...". The addon seems to be added into my Addons list, but when I search for it in Blender, it cannot be found.  Is there anything I can do to use this addon?


I've tried to make a regular expression that match anything except if contains a 11 digits like 12345678910 so don't match anything  what i have tried  [^\d{11}]   but {11} doesn't work with \d expression so what i have to do ?

I know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, is it possible to match lines that do not contain a specific word, e.g. hede, using a regular expression?   Input:  hoho hihi haha hede   Code:  grep "<Regex for 'doesn't contain hede'>" input   Desired output:  hoho hihi haha


How can I prove that every subring of $\mathbb{Q}$ is PID?

Let $A$ be a PID and $R$ a ring such that $A\subset R \subset \operatorname{Frac}(A)$, where $\operatorname{Frac}(A)$ denotes the field of fractions of $A$. How to show $R$ is also a PID?   Any hints?


I have an HTML table which has a few rows which has a edit button in the last column. In order to avoid reloading of page unnecessarily I have placed a form beside the table which will insert data into the DB via AJAX, which will return a JSON string with the object data. I have to append this data into the table. I know how to append the data but I'm getting an unexpected string error in the browser on the jquery function precisely in the line where the button is present. The onclick function is given below.  $("#subBtn").click(function(){         $.post("/EmployeeSpringMVC/newRule",                 {                     name: $("#ruleName").val(),                     desc: $("#ruleDesc").val(),                     startDate: $("#ruleStartDate").val(),                     severity: $("#ruleSeverity").val()                 },                 function(data, status){                      alert("Data: " + data + "\nStatus: " + status);                      var rule = jQuery.parseJSON( data );                      var edtbtn = "<button class='btn btn-primary btn-sm editBtn'" +                             "onclick='editBtnClick(" + rule.ruleId + ", '" + rule.ruleName + "', '" + rule.ruleDesc "', '" + rule.startDate + "', '" + rule.ruleSeverity + "')'>" +                             "" +                             "Edit</button>";                      var row = "
" +                                     "" + rule.ruleName + "	" +                                      "" + rule.ruleDesc + "	" +                                     "" + rule.startDate + "	" +                                     "" + rule.ruleSeverity + "	" +                                     "" + edtbtn +                                     "<button onclick='window.location = '/EmployeeSpringMVC/delRule/${rule.ruleId}''" +                                     "data-method='delete' class='btn btn-danger btn-sm'>" +                                     "" +                                      "Delete</button>	" +                                     "
";                      $('#records_table').append(row);                  });     });   The line with the error is  var edtbtn = "<button class='btn btn-primary btn-sm editBtn'" +                             "onclick='editBtnClick(" + rule.ruleId + ", '" + rule.ruleName + "', '" + rule.ruleDesc "', '" + rule.startDate + "', '" + rule.ruleSeverity + "')'>" +                             "" +                             "Edit</button>";   What is wrong with this and is there a better way to do this? The difference to this question is that I'm trying to appending a row which has a button which has a javascript call to a function given below.  function editBtnClick(id, name, desc, startDate, severity){     $("#ruleForm").attr("action", "/EmployeeSpringMVC/updRule");     $("#ruleId").val(id);     $("#ruleName").val(name);     $("#ruleDesc").val(desc);     $("#ruleStartDate").val(startDate);     $("ruleSeverity").val(severity);     $("#ruleIdDiv").css("display", "inline");     $("#updBtn").css("display", "inline");     $("#subBtn").css("display", "none"); }   I felt this was easier than selecting the data from the HTML page after the button click is recognized in jquery.

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.


What's a regex pattern (in PHP) that replaces a string with hyperlinks, where the text preceding a URL is used as the anchor text for the link?  For example:  text a http://example.com ending text   becomes   text a ending text   In other words, the text preceding the URL becomes the anchor text for the link.   What I really want is a variation of the following function by snipe  but with the twist above.

I have the following string:  "Look on http://www.google.com".   I need to convert it to:     "Look on "   The original string can have more than 1 URL string.  How do I do this in php?  Thanks


I have a bash code export TM_SCALAC=${TM_SCALAC:-scalac}.  I'm not sure the meaning of ":-" inside the ${}. How do I interpret this line of bash code?

I saw this in the end of an awesome shell script but I can't understand the login here because I think it's being short-handed for a longer command.  spark ${@:-`cat`}   This apears at the end of . Any ideas?  + Marks for some one who extends it into a full segment of code, even if its slower (Better for explanation)


I’m posting my question because I read this original post. The post was from 2016, so I’m reposting in hopes that someone can answer. Here’s the original post:  (Also, do not flag as duplicate. If you read my experience below, the answers from the previous post do not explain why this is happening.)    I'm sitting in a room next to some totally unopened cans of carbonated soft drinks (if it matters — the two affected cans are Coke Zero and Diet Coke). These cans were unboxed approximately two days ago and were full, but now are seemingly mostly empty!  There is no puncture in either can, and compressing them results in the dent being counteracted by pressure inside the can. Shaking and weighing the can (by hand; I don't have a scale anywhere near) reveals that a good majority (75%) of the can is now effectively empty.  The cans spent the whole time stored inside a normal room with a temperature of ±22ºC and automatic fluorescent lighting which is on for 16 hours a day.  Finally, there is no condensed drink on the outside wall of the can, and the cans themselves are externally room temperature, so I'm really puzzled about what process could do this.  I'm hesitant to open the cans because I'm not sure what the result of that could be, however if it's deemed here that there's little or no risk, I'll do that and update the question.  What possible reason could there be for these cans becoming empty?    Now here is my post/question:  I know exactly what you are talking about! Only my soda cans were not expired! I have a soda machine that I purchased about 10 years back. I load the machine myself with different sodas...coke, Diet Coke, sprite, dr.pepper etc....so I know that the cans are full when I put them in there.  Over the past 10 years I have found around 10-15 cans that are totally empty. Sometimes there might be a small amount of soda in them, but not much. There are no puncture holes, no sticky residue on the can, nor any residue inside the machine. Every time I found one, I thought I was going to have to clean up a mess....but nope, no mess..nothing. There is still pressure inside the can...not as much as a regular can, but there is still pressure. I’ve opened all of them. No bad reactions! Haha!  I’ve looked at the seal at the top of the can. I’ve even put one under water to look for leaking bubbles. Nothing... I’ve been perplexed for years and have asked everyone I know, and I have yet to find a viable explanation. If anyone can fill me in, I would love to know the answer!


I'm trying to detect if there's any pattern (seasonality) between login attempts on a machine using python. After researching a little bit i stumbled upon the library pmdarima, providing statistical tests such as the Canova-Hansen test to estimate the seasonal differencing term. All the tests however requires knowing apriori the parameter m which indicates the number of observations per seasonal cycle. However data are observed all the time every millisecond therefore one day i could have 500 logins, another day i could have 70 logins and another one none at all. let's say i want to test seasonality in one month period, or one week period,how should i go about selecting the coefficient for the test? Thanks in advance

This post is the continuation of another post related to a . Basically, at this point I'm interested in a robust way to discover the periodicity/seasonality of a generic time series affected by a lot of noise. From a developer point of view, I would like a simple interface such as:  unsigned int discover_period(vector<double> v);  Where v is the array containing the samples, and the return value is the period of the signal. The main point is that, again, I can't make any assumption regarding the analyzed signal. I already tried an approach based on the signal autocorrelation (detecting the peaks of a correlogram), but it's not robust as I would like.


I'm trying to plot the course for my organization and am currently looking at (not exclusively so, but so far research leads to these):  Zenoss  Nagios  OpenNMS  Our requirements is that this must be freely licensed, support SNMP/WMI monitoring, as well as alternative monitoring for situations where firewalls block SNMP/WMI (eg: webservice, TCP, agent)  At a minimum we're looking for graphical network map with uptime statistics, traffic stats, service availability, and hardware monitoring.  We have a custom agent that collects very detailed/granular hardware information on our supported systems , and will be making efforts to tie this into whatever NMS we choose. That sort of piqued my interest on OpenNMS as we might be able to directly forward our data to our NMS system without a lot of fidgeting.  Can someone help elaborate what I can do with Zenoss vs nagios? Any product will be likely used as the "free' version.  I suppose VMWare/Virtualization support for monitoring VMs is something that should be considered as well.  Trying to digest a lot of information and any help/guidance is appreciated!

This is a  about Monitoring Software. Also Related:   I need to monitor my servers; what do I need to consider when deciding on a monitoring solution?


My dual boot computer has Microsoft Windows and Ubuntu 13.10 installed. Suggestions on this website recommend setting the time parameter for Ubuntu to manual. I did that. In fact, I changed both the Microsoft Windows setting and the Ubuntu setting to manual. However, the time conflict still shows.   Why is Ubuntu picking up the system time setting as GMT + 0.00 and what can I do to change this bizarre error?

Dual boot system Windows XP Pro and Ubuntu 12.04.  I have the bios set for the correct time and Ubuntu set for US Eastern time.  Ubuntu will boot up and the time will be off by -4 hours.  If I correct the time in Ubuntu then when I boot up in Windows XP the time will be off by + 4 hours.  This is a fresh install of 12.04. I did not have this problem before reinstalling Ubuntu.


My Careers 2.0 profile has up-to-date (within a few days) reputation information for all of the Stack Exchange sites except for User Experience (UX), which still shows me at 101 reputation. I have been actively participating in UX questions for over two weeks, and have yet to see any changes to the reputation score on my Careers profile, let alone an up-to-date score.  Careers profile:   UX Stack Exchange profile:

When I look at my reputation on stackoverflow I see one number, but when I look at my profile in the careers.stackoverflow I see another number.  Is it just slow to update (maybe it's a few days behind...)?  UPDATE:  Looks like this problem has been solved.  As of 5-28-14 my reputation levels in stackoverflow and careers.stackoverflow are now consistent.  Thanks to those doing the fixing!


what exactly is a correlation of zero meant to be, does that mean that changes in x does not affect y, if that is the case, from the scatter plot  That is completely false, as sometimes as x increases, y decreases or increases

What is covariance in plain language and how is it linked to the terms dependence, correlation and variance-covariance structure with respect to repeated-measures designs?


Floor topology on R : - Topology generated by basis containing half open intervals [a,b) where a < b are real numbers. Does it have a countable basis?

I am trying to understand this proof from Munkres' book which shows that the Sorgenfrey line does not have a countable basis. His proof is:  Let $\beta$ be a basis for $\mathbb{R}_l$. Choose for each $x$ an element $B_x \in \beta$ such that $x \in B_x \subset [x, x+1)$. If $y$ is not equal to $x$ then $B_y \neq B_x$ since inf($B_x$) = $x$ and $y$ = inf($B_y$). Therefore $\beta$ must be uncountable.   I am new to topology so I am probably just missing a simple point but I do not see why $\beta$ must be uncountable according to this argument. I agree that $B_y \neq B_x$ but isn't it possible that $y \in B_x$ (and thus the set $B_y$ is not needed as part of the basis)? Thanks in advance for your help.


Recently I was looking through developer options on my Moto X and I was interested by the option to do runtime in either dalvik or ART. After doing some research I decided to change my runtime to ART. I was wondering if this was a good choice or if I should continue running my phone on Dalvik. Let me know what you think.

ART has better performance and better battery life on paper at least.  Should I consider switching to it on my moto g? What are the results I can expect? What precautions should I take? Is it easy to turn back to dalvik?


If I want to ask my teacher the exercise we are at which of the following sentences should I use?     1 "which exercise are we at?"      2 "what exercise are we in?"

In this two cases what we should use? What or Which?     1) what/which email program do you use   2) what/which accounts have this problem   Thanks.


I saw this movie when I was a very young kid with my grandpa circa 1995-1997. I don't remember when the movie was actually produced, but I have a feeling it wasn't a very old movie, like pre 1990s, or an 80s, 70s movie. It should have been made around 1990-1996. I remember the graphics of the aliens were good at the time (although if I saw them now they would probably look cartoon-ish). My guess is it a b-movie horror flick (most likely with bad ratings).  It was an adult movie (but he didn't care). It was certainly very frightening to me at the time and there was a lot of blood and even aliens eating people (I don't remember many more details though). I was glued to the screen. I remember there were rounded-shape aliens, or strange looking red demon like creatures that appeared not to just haunt but actually attack a group of people that were stranded in an abandoned airport. It's not much of a thriller movie, but horror & science fiction I believe, with a touch of mystery before the aliens made their full on appearance and were trying to eat everyone. By the way it was an American movie, everyone was speaking English.  I can't remember how this group of people got themselves there, their airplane crashed (but how would they survive then?) or something else happened. But I do remember it was an abandoned airport for sure. They found themselves stranded there and there was NOBODY there. They tried to call for help but all communications were down (not 100% sure on this). It was a wide open desert-like field (looked like Arizona or Colorado). I don't remember any of the actors either, but a white male protagonist on the role and a white female as well as a few other people in the group of various colors etc. It had a mystery feel on the first half of the movie and the other half was horror. I don't remember what happens in the end either. I do sort of remember they reach the conclusion that the aliens ate everyone there though.  I remember that those were in fact aliens and not demons. The movie was clinging on Sci-Fi not paranormal (that's why I don't think they were demons). Pretty sure on the alien part.  I have a clue as to how the group found themselves there. I believe it is correct. Their airplane needed emergency refueling, so by radar the pilot found a nearby airport (but I don't believe he communicated with someone). So they decided to make an emergency landing and upon arrival they could not find ANYONE there. So they were looking around, the passengers were curious. All in all the group of people couldn't have been more than 20. I remember the airplane that got them there was quite big but that doesn't justify the fact that the people were few in numbers.

I thought it was The Tommyknockers by Stephen King, but after a check with Wikipedia, it appears that's not the case.  What I remember about the story (a TV movie I think, but definitely based on a book) was that the world is created anew every night, and that the old, used up, Earth was eaten nightly by some scary creatures.  The major plot point involved some protagonists not getting onto the new world at midnight, and having to escape from the monsters that were eating up yesterday's planet.  Does this ring a bell for anyone? I'm finding it very hard to Google for.


$f(x)\in \mathbb Q,$ if $x\not\in \mathbb Q$ and $f(x)\not\in \mathbb Q$, if $x\in \mathbb Q$. Can $f$ be continuous?   I have tried using the sequential definition of continuity on rational and irrational sequences, but not getting anywhere.  Any suggestions?

Is there a way to prove the following result using connectedness?  Result:  Let $J=\mathbb{R} \setminus \mathbb{Q}$ denote the set of irrational numbers. There is no continuous map $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f(\mathbb{Q}) \subseteq J$ and $f(J) \subseteq \mathbb{Q}$.


I was simulating the above circuit in LTspice...  I realize the main problem here is the 2MHz peak (which should be fixable with proper compensation), but I'm curious about the smaller 398kHz peak that's seen in the output noise density plot.  This matches up perfectly with the pole that is created by the LT1028 parasitic input capacitance and output impedance (5pF, 80 ohms).  What is the mechanism of this creating an output noise peak though? I understand that input capacitance increases the noise gain of an amplifier.  However, I'd like to understand why this creates a peak in the noise rather than just an increase in the noise level.

On the image below you can see an inverting amplifier with input capacity C1 and capacity C_F for general stability.     Now my book shows me following frequency plot:  A_n ... Noise-Gain  A_D ... open-loop gain  A_U ... V_out / V_in --> inverting amplifier gain     You can clearly see that C1 is increasing the noise gain at some point. And C_f is stabilizing A_n and A_U.   But why exactly does C1 increase the noise gain exactly?


I have a Sapphire R9 380X and i tried to install Ubuntu 16.04.3 but when i press Install Ubuntu on GRUB the screen turns off and the fans spin at maximum speed and i cant get into the installer. In Ubuntu 16.04.2 and Kernel 4.8 it was working fine. I saw at AMD  that they have released a new driver for Kernel 4.10 but i was using the out of the box driver that ubuntu used "amdgpu". Why it isnt working now?

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:


Similar to the  Trigger.isInsert, is there a way to determine if a record was created (as opposed to edited), in a criteria in Process Builder?  I tried using ISCHANGED(CreatedDate), but it appears that the process is fired after database insertion, so this doesn't do the job...  I can probably use something like (pseudocode) CreatedDate >= NOW() - 10s, but this seems rather inelegant, and could fail in edge cases (e.g. someone edits immediately after creation, or on record creation the system lags and the process doesn't fire in the expected window of time).  Is there a simple solution to this that I'm overlooking?

How do I set up criteria in Process Builder to detect Insert? I have tried setting Field to Id and Filter to IsChanged, WasSet, and IsNull, all to no avail. I want a process to take one action when a record is inserted, and make sure all subsequent criteria apply only on update.  Is this issue perhaps because I am trying to detect a change from null? I found  on the Ideas Exchange that may be relevant.