I am really struggling with coming up with comparison series for doing the Limit Comparison tests, especially when $n$ is in the exponent.  For the series $$\sum_{n=0}^\infty  \frac{n +2^n}{n+3^n} $$  Could some walk me through how to find a comparison series for this question to determine convergence or divergence? I can only use the comparison test and not another test.  I want to compare it to $$\sum_{n=0}^\infty  = \left(\frac{2}{3}\right)^n $$ Which is a convergent geometric series with $|r| = \frac{2}{3}<1$, but this answer is wrong and I am stumped.

The sum is $$\sum_{n=1}^{\infty} \frac{n+2^n}{n+3^n}$$ Is this convergent or divergent? I tried to use the divergent test but the test fail because $a_n = (n+2^n)/(n+3^n) = 0 $ as $n$ goes to infinity. Could someone point me to the right direction?  Thanks


How can I prevent (certain cronjobs) from filling my syslog in Ubuntu 15.04? I have some jobs that run 4 times a minute and quickly fill up my syslog files.  I've tried adding:  cron.*                                                  /var/log/cron   to /etc/rsyslog.conf, but this didn't resolve anything.  The current output is:  Aug  8 06:58:01 localhost CRON[25706]: (gijs) CMD (   sleep 15; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 localhost CRON[25703]: (gijs) CMD (   sleep 30; unison -batch /var/www ssh://server2//var/www) Aug  8 06:58:01 localhost CRON[25708]: (gijs) CMD (unison -batch /var/www ssh://server2//var/www) Aug  8 06:58:01 localhost CRON[25713]: (gijs) CMD (   sleep 30; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 localhost CRON[25714]: (gijs) CMD (   sleep 45; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 localhost CRON[25717]: (gijs) CMD (   unison -batch /var/www ssh:// server3//var/www) Aug  8 06:58:01 localhost CRON[25719]: (gijs) CMD (   sleep 15; unison -batch /var/www ssh:// server3//var/www) Aug  8 06:58:01 localhost CRON[25690]: (CRON) info (No MTA installed, discarding output) Aug  8 06:58:01 localhost CRON[25694]: (CRON) info (No MTA installed, discarding output) Aug  8 06:58:08 localhost CRON[25588]: (CRON) info (No MTA installed, discarding output)

How can I prevent (certain cronjobs) from filling my syslog in Ubuntu 15.04? I have some jobs that run 4 times a minute and quickly fill up my syslog files.  I've tried adding:  cron.*                                                  /var/log/cron   to /etc/rsyslog.conf, but this didn't resolve anything.  The current output is:  Aug  8 06:58:01 elitegameservers CRON[25706]: (gijs) CMD (   sleep 15; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 elitegameservers CRON[25703]: (gijs) CMD (   sleep 30; unison -batch /var/www ssh://server2//var/www) Aug  8 06:58:01 elitegameservers CRON[25708]: (gijs) CMD (unison -batch /var/www ssh://server2//var/www) Aug  8 06:58:01 elitegameservers CRON[25713]: (gijs) CMD (   sleep 30; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 elitegameservers CRON[25714]: (gijs) CMD (   sleep 45; unison -batch /var/www ssh://server1//var/www) Aug  8 06:58:01 elitegameservers CRON[25717]: (gijs) CMD (   unison -batch /var/www ssh:// server3//var/www) Aug  8 06:58:01 elitegameservers CRON[25719]: (gijs) CMD (   sleep 15; unison -batch /var/www ssh:// server3//var/www) Aug  8 06:58:01 elitegameservers CRON[25690]: (CRON) info (No MTA installed, discarding output) Aug  8 06:58:01 elitegameservers CRON[25694]: (CRON) info (No MTA installed, discarding output) Aug  8 06:58:08 elitegameservers CRON[25588]: (CRON) info (No MTA installed, discarding output)


I'm making a curl request where it displays an html output in the console like this   Warning:  Cannot modify header information - headers already sent by (output started at /home/domain/public_html/wp-content/themes/explicit/functions/ajax.php:87) in /home/domain/public_html/wp-content/themes/explicit/functions/ajax.php on line 149
......   etc  I need to hide these outputs when running the CURL requests, tried running the CURL like this  curl -s 'http://example.com'   But it still displays the output, how can I hide the output?   Thanks

I have a couple of scripts in my bash file, that should do certain tasks, say like ...   #!bin/bash yum -y update service restart nginx yum install atop cat /var/log/somelog.log > /home/cron/php/script   It goes on and on, but the problem is that with each task taken, bash shows me the output. Like  service restart nginx for example, outputs some message. And I want to hide all these messages. What is generally the accepted way of achieving this? Because, I was about to redirect the STDOUT to /dev/null but, considering I have over 50 consecutive tasks to run, it would mean I have to /dev/null that much, which for some reason does not seem efficient to me.


I'm developing an application in .NET where the user can provide Regular Expressions that are afterwards used to validate input data.  I need a way to know if a regular expression is actually valid for the .net regex engine.   Thanks for any help

I allow users to enter a regular expression to match IP addresses, for doing an IP filtration in a related system. I would like to validate if the entered regular expressions are valid as a lot of userse will mess op, with good intentions though.  I can of course do a Regex.IsMatch() inside a try/catch and see if it blows up that way, but are there any smarter ways of doing it? Speed is not an issue as such, I just prefer to avoid throwing exceptions for no reason.


This question was  but I decided to make it a feature request and ask it here after some advice from a Writers mod. I was wondering if we could make the migration search function for moderators be made available to regular users? One reason for closing is that the question should belong on a different SE site. The pop-up box only gives you a couple possible sites to migrate the question to (depending on what site the question was asked on). For example, in Writing SE, it gives you the migration options of Writing Meta and EL&U. (see picture at the bottom) Could we include a search bar to pick any SE site to migrate to instead of just a couple of options? Most of the time, the question should be moved to the relevant options in the pop-up box - but there are oddball questions that should be moved to a different SE site than the given options. I understand that moderators have this ability, but why not give it to regular users? It would not hurt - it would actually make things more convenient. (example)

I think there should be more Stack Exchange networks available when flagging a question to be migrated. For example I'd think that the following question:    ...would be a better fit on unix.stackexchange.com instead of Stack Overflow. But without the option to mark it so, I feel hesitant to mark it.


I would like to automatically track the time when a point is created or edited. I first thought about virtual fields and the now() function. However, that field always contains the current time. So maybe it would be possible to only update the virtual field one time, but I have no clue how. Is there a way or any other possibility to automatically track the time?  In contrast to the question  or rather the answers I don't think it is reasonable to select a field or save the shapefile every time after editing a new feature. So yes the quesions may be similar, but the answers of the other question don't answer my question.

I want to make a date and time updated field as I edit an attribute field in this format yyyy-mm-dd 00:00:00 (= 2016-05-08 11:04:00) - my local date/time. The data is in a QGIS 2.14 shapefile and vector lines as screenshot below. When a feature as NULL in the 'name' field, I want to enter a name for the road and the 'mod' field must receive de modified date/time like '2016-05-08 15:16:00'. I already tried some options and failed. I need help to start from beginning.  I create a new field, date/time type, but stays with NULL value after I edited, in the "name" field, or the feature itself. I used too, the expression now(), but stays with NULL value after I edited.  Note: the date seen there, 2016-04-14 is the first value created with "Field Calculator".  I am using QGIS 2.14.


When I learnt about shm 2 weeks ago I was confused why SHM $x$-$t$ relation) is represented by sine or cosine function. It is hard to imagine the motion of pendulum as a sine or cosine motion (quite impossible). As of now I learnt the whole chapter.  I answered my confusion by guessing that: - As SHM is periodic, it is represented by a sine or cosine function. Is this guess correct?  But at the end I still have a small doubt that whether it is sine/cos because it is periodic or the motion of pendulum is LITERALLY sine or cosine motion.

I am a Math Grad student with a little bit of interest in physics. Recently I looked into the Wikipedia page for .  Guess, I am too bad at physics to understand it. Considering me as a layman  how would one explain:   What a Simple Harmonic motion is? And why does this motion have such an equation $$x(t)= A \cos(\omega{t} + \varphi)$$   associated with it? Can anyone give examples of where S.H.M. is tangible in Nature?


In applying a penalty term with either $l_1$ or $l_2$ norm, why would the former result in variable selection but not the latter?

I've been reading , and I would like to know why the Lasso provides variable selection and ridge regression doesn't.  Both methods minimize the residual sum of squares and have a constraint on the possible values of the parameters $\beta$. For the Lasso, the constraint is $||\beta||_1 \le t$, whereas for ridge it is $||\beta||_2 \le t$, for some $t$.  I've seen the diamond vs ellipse picture in the book and I have some intuition as for why the Lasso can hit the corners of the constrained region, which implies that one of the coefficients is set to zero. However, my intuition is rather weak, and I'm not convinced. It should be easy to see, but I don't know why this is true.  So I guess I'm looking for a mathematical justification, or an intuitive explanation of why the contours of the residual sum of squares are likely to hit the corners of the  $||\beta||_1$ constrained region (whereas this situation is unlikely if the constraint is $||\beta||_2$).


My old server will be suspended and I will get another server. I have just WordPress on it.  What do I need to do to make a perfect (without problems) switch to the new server? What I already did is, saving all the data on the server via filezilla to my desktop. And I exported my database via phpmyadmin. What now?

i'm planning to migrate my server from one hosting to another, hence I need to change the dns for my domain name. but the problem is, dns propagating takes a few hours to really complete. Problem is, my site has few thousands users and they enter data daily on my site. What is the best practice on server migration? because i don't want any non-synchronized or non-updated database later.


I just want to confirm if it is possible to reverse the sign (+/-) on the factor loadings of one factor. I run a PAF with Oblimin rotation. I obtained 6 factors but in one of them the items that load into the factor have negative values. I have read that this is not relevant in terms of interpreting within a factor so one could change all the signs of the factor to facilitate interpretation, for example, in the correlation matrix.  I am using SPSS. Maybe an image would help me to explain better. My question is in relation to factor 4.

I performed principal component analysis (PCA) with R using two different functions (prcomp and princomp) and observed that the PCA scores differed in sign. How can it be?  Consider this:  set.seed(999) prcomp(data.frame(1:10,rnorm(10)))$x              PC1        PC2  [1,] -4.508620 -0.2567655  [2,] -3.373772 -1.1369417  [3,] -2.679669  1.0903445  [4,] -1.615837  0.7108631  [5,] -0.548879  0.3093389  [6,]  0.481756  0.1639112  [7,]  1.656178 -0.9952875  [8,]  2.560345 -0.2490548  [9,]  3.508442  0.1874520 [10,]  4.520055  0.1761397  set.seed(999) princomp(data.frame(1:10,rnorm(10)))$scores          Comp.1     Comp.2  [1,]  4.508620  0.2567655  [2,]  3.373772  1.1369417  [3,]  2.679669 -1.0903445  [4,]  1.615837 -0.7108631  [5,]  0.548879 -0.3093389  [6,] -0.481756 -0.1639112  [7,] -1.656178  0.9952875  [8,] -2.560345  0.2490548  [9,] -3.508442 -0.1874520 [10,] -4.520055 -0.1761397   Why do the signs (+/-) differ for the two analyses? If I was then using principal components PC1 and PC2 as predictors in a regression, i.e. lm(y ~ PC1 + PC2), this would completely change my understanding of the effect of the two variables on y depending on which method I used! How could I then say that PC1 has e.g. a positive effect on y and PC2 has e.g. a negative effect on y?    In addition: If the sign of PCA components is meaningless, is this true for factor analysis (FA) as well? Is it acceptable to flip (reverse) the sign of individual PCA/FA component scores (or of loadings, as a column of loading matrix)?


Which of the following is correct?   How much salt and pepper was added to the soup? How much salt and pepper were added to the soup?   In other words, should "salt and pepper" be followed by a singular or a plural verb? Please also explain why.

I am having trouble with the following sentence:      "The complexity and diversity of the new platforms is worrying us."   If "complexity" and "diversity" constitute two subjects, then the verb should presumably be "are"; however, the sentence feels more natural with "is". Is this correct? Is there a linguistic term for this occurrence?    The following questions address the general topic of compound subjects, but not specific cases like this:             And the following question seems to have somewhat inconclusive answers:         So this question is not really a duplicate of these three.


I am using a USB extension lead to extend the length of my usb cable and I am wondering do these slow down the transfer of data from an external hard drive to the machine.

Recently I've been thinking of upgrading my computer with some USB 3.0 ports. However, the problem is my computer is some ways away from my desk so that would mean I would need a long cable, approximately 10ft or so.  My question is how badly does a long cable (10ft for example) impact the transfer rates of USB 3.0? At what point will the USB controller revert back to say, high speed mode as opposed to super speed mode? What have you guys experienced?  Thanks


So I wanted to create a citation like the following:  US. Census Bureau (2017). Retrieved from https://.....  I have tried the following: @Online{USCensusBureau2017, label = {United States Census Bureau}, Title = {Statistics of U.S. Businesses (SUSB)}, url = {https:...}, author = {United States Census Bureau}, year = {2017} }  But it gives me a formatted bibliographic entry like this: U.  S.  C.  Bureau.   Statistics  of  u.s.  businesses  (susb),  2017. URL https://.....  Could you tell me how I can achieve what I need? Thank you!

I want to list a company name in the author field of a bibliographic entry:  @book{CUDA,   author    = {NVIDIA Corporation},   title     = {NVIDIA CUDA Compute Unified Device Architecture Programming Guide},   publisher = {NVIDIA Corporation},   year      = {2007} }   But the entry keeps showing up "N. Corporation".  Is there a way to get the full author name to show up?  I'm currently using the siam BibTEX style.


I've been looking for information about creating a folder of size x, for example, 3 gigabytes and I only found it for the files with dd but it's not that I need it. You have some way of creating it someone could tell me, or if there is some tool for it. Thank you all

I have a directory on my system which is used for a specific reason by applications and users, but I don't want its size to be allowed to exceed 2GB, is there a way of setting up some sort of limit which just doesn't allow the file size to exceed that or any other amount I decide to set for it in the future?  When the size limit is exceeded it should undo the last change (though there should be an option to have it so that it just stops the operation and doesn't care if half a file was copied and left there) and then display a warning to the user.   I am running Ubuntu GNOME 16.10 with GNOME 3.22.


I got a string like:  settings.functionName + '(' + t.parentNode.id + ')';   that I want to translate into a function call like so:  clickedOnItem(IdofParent);   This of course will have to be done in JavaScript.  When I do an alert on settings.functionName + '(' + t.parentNode.id + ')'; it seems to get everything correct.  I just need to call the function that it would translate into.  Legend:  settings.functionName = clickedOnItem  t.parentNode.id = IdofParent

I have the name of a function in JavaScript as a string. How do I convert that into a function pointer so I can call it later?  Depending on the circumstances, I may need to pass various arguments into the method too.  Some of the functions may take the form of namespace.namespace.function(args[...]).


I'm trying to output this to a file and print it at the same time, I've tried to use > test.txt behind "scan" but that didn't work, anyone have any suggestions? sudo iwlist wlan0 scan | awk -F ':' '/ESSID:/ {print $2;}'

My aim is to log all output from a script into a directory that the script is going to create.  For example, I have:  ~/.abc.sh:  #! /bin/bash rails new myapp   When I run...  cd ~/code . ~/.abc.sh   ...that will create a new Rails app in directory ~/code/myapp.  When Rails is creating an app, it outputs a whole lot of text that I want to capture and store in a log file in the same directory the rails command newly created. I also want to display that text in the terminal as well.  How do I go about doing this?


My partner, who is Thai, has just become an Australian citizen. He is not supposed to hold both. We are going to Thailand. Should he travel on the Australian passport or should he use both passports? Would he leave and reenter on his Australian passport and enter and leave Thailand on his Thai passport? Would there be any problems at the Thai end?

I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling?


I am uploading a file to a folder , i had given the file name as "1.jpg" , so when i am uploading a new file it will overwrite the existing one, So How i can give a random file name to the file which i am uploading  MY UPLOAD CODE IS HERE  @RequestMapping(value = "/event/uploadFile",headers=("content-type=multipart/*"), method = RequestMethod.POST,consumes ={"application/x-www-form-urlencoded"})     //String quote_upload=C:\fakepath\images.jpg     public @ResponseBody     String uploadFileHandler(              @RequestParam MultipartFile file) {         System.out.println("Creating the directory to store file");          if (!file.isEmpty()) {             try {                 byte[] bytes = file.getBytes();                   // Creating the directory to store file                 String rootPath = System.getProperty("catalina.home");                 File dir = new File(rootPath + File.separator + "tmpFiles");                 if (!dir.exists())                     dir.mkdirs();                  // Create the file on server                 File serverFile = new File(dir.getAbsolutePath()                         + File.separator+"1.jpg");                 BufferedOutputStream stream = new BufferedOutputStream(                         new FileOutputStream(serverFile));                 stream.write(bytes);                 stream.close();                  System.out.println("************Server File Location="                         + serverFile.getAbsolutePath());                  //return "You successfully uploaded file=" + name;             } catch (Exception e) {                 System.out.println("************failes"+ e.getMessage());                 //return "You failed to upload " + name + " => " + e.getMessage();             }             //return "You failed to upload " + name                     //+ " because the file was empty.";         }         System.out.println("hello");         return "hello";     }

I've been looking for a simple Java algorithm to generate a pseudo-random alpha-numeric string.  In my situation it would be used as a unique session/key identifier that would "likely" be unique over 500K+ generation (my needs don't really require anything much more sophisticated).    Ideally, I would be able to specify a length depending on my uniqueness needs. For example, a generated string of length 12 might look something like "AEYGF7K0DM1X".


I'm trying to understand how System.out can invoke println(). All the searches  say System.out is an instance of PrintStream class therefore it can invoke a method in that class.  BUT...  When I try to duplicate this with the following a NullPointerException results.  public class Main {     public static void main(String[] args){         Tasker.calc.add(1, 2);     } }  class Tasker{     static Calc calc; }  class Calc {     public void add(int x, int y){         System.out.println(x+y);     } }   Isn't Tasker.calc a similar instance of Calc? How is System.out not a NullPointerException?  To be clear, this is not a question about NullPointerException... this is a question about why System.out doesn't require initialization.  Thanks a bunch!

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?


from datetime import datetime x="Hello, it is now %s." % datetime.now().strftime('%d-%m-%Y %H:%M:%S') import csv try:     with open('output.csv', 'w+') as csvFile:         writer=csv.writer(csvFile)         writer.writerow(x.encode('UTF-8'))         print(x.encode('UTF-8')) finally:     csvFile.close() import pandas as pd data = pd.read_csv('output.csv') data.to_excel('output.xlsx')   UBUNTU code  attyan22@LAPTOP-SGBTV53C:/tmp/sysv-rc-conf-0.99$ crontab -l * * * * * /usr/bin/python/c/Users/a.sakata/Desktop/python_lesson/hello_time.py   but it does not work, so I checked if top run or not  attyan22@LAPTOP-SGBTV53C:/tmp/sysv-rc-conf-0.99$ sudo apt-get install chkconfig Reading package lists... Done Building dependency tree Reading state information... Done Package chkconfig is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'chkconfig' has no installation candidate attyan22@LAPTOP-SGBTV53C:/tmp/sysv-rc-conf-0.99$ sudo apt-get install sysv-    rc-conf Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package sysv-rc-conf   it cannot install  why how

I have this python script. I'm trying to run it on a crontab, but it isn't working:      from datetime import datetime x="Hello, it is now %s." % datetime.now().strftime('%d-%m-%Y %H:%M:%S') import csv try:     with open('output.csv', 'w+') as csvFile:         writer=csv.writer(csvFile)         writer.writerow(x) finally:     csvFile.close()   The crontab is defined as:  attyan22@LAPTOP-SGBTV53C:~$ crontab -l * * * * * python hello_time.py   attyan22@LAPTOP-SGBTV53C:~$ service crond start crond: unrecognized service   I want to run automatically, but it does not working. This is just test .


How should I see that the set of almost complex structures on $R^4$ preserving the positive orientation, namely $\{J\in GL^{+}(4,R), J^2=-I\}$ is homotopy equialent to $S^2$.   There is a similar question asked before, but I need more details as why this  set is $GL^{+}(4,R)/GL(2,C)$, etc.

The set of almost complex structures on $\mathbb R^{2n}$ is given by $$ M_n = \frac{GL(2n,\mathbb R)}{GL(n,\mathbb C)} = \mathcal C_+ \sqcup \mathcal C_-,$$ taking into account that $\det = \pm 1$ gives two disjoint sets.  How do we show that $M_2=S^2 \sqcup S^2$? Moreover, I'm a bit confused by dimensions: how does $\dim_{\mathbb R}M_2=8$ relates with the latter decomposition?  This is exercise 1.2.1 from the book Complex geometry by Huybrechts.


Since $$\lim_{n\to\infty}(\frac{n-k}{n})^n=e^{-k}$$ We can predict that: $$\lim_{n\to\infty}(1^n+2^n+…+n^n) /n^n=\sum_{k=0}^\infty e^{-k}=\frac{e}{e-1}$$ However, I think the solution is NOT strict enough. Although I have a rigorous proof for this, I want a easier solution.$$$$My solution as follows:

Now I want to find the limit   $$\lim_{n\to\infty}\frac{\sum\limits_{k=1}^n k^n}{n^n}.$$ I try to use the Stolz theorem as follows: $$\lim_{n\to \infty}\frac{\sum_{k=1}^n k^n}{n^n}=   \lim_{n\to \infty}\frac{\sum_{k=1}^{n+1} k^{n+1}-\sum_{k=1}^n k^n}{(n+1)^{n+1}-n^n}$$ $$=\lim_{n\to\infty}\frac{(n+1)^{n+1}+\sum_{k=1}^n(k^{n+1}-k^n)}{(n+1)^{n+1}-n^n}$$ $$=1+\lim_{n\to\infty}\frac{\sum_{k=1}^n(k^{n+1}-k^n)}{(n+1)^{n+1}}.$$ It seems to deal with the summation like this form: $$\sum_{k=1}^{n}k^p,\text{with}\ p=n,n+1.$$ I have no way to deal this summation, any help and hint will welcome!


Why there are two lists stacked onto each other when I'm using ALT + TAB?  This problem was on Ubuntu 16.04 and still persists after upgrade to 18.04?   Sorry for poor quality, had to take the photo with phone as you can't make a screenshot while ALT key is pressed.

I started to have problems with my Ubuntu application switcher (Alt +  Tab) this morning. When I press Alt +  Tab, not only one, but two application switchers show up. Last night I customized some stuff using the Unity Tweak Tool. I thought I didn't touch the application switcher. So now it looks like this:


Time and again, I've been told that the change in the velocity of light makes it bend at the interface between two different media. But is there any explanation as to why that change occurs? Or is it one of those things that you just have to accept, like positive charge attracting a negative charge, or something like that?

So light travels slower in glass (for example) than in a vacuum. What causes light to slow down? Or: How does it slow down? If light passes through the medium, is it not essentially traveling in the "vacuum" between the atoms?


I this select box :  <select id="owner_select">   <option value="1">Hasan</option>   <option value="5">aUser1</option>   <option value="7">aUser2</option>   <option value="8">aUser3</option> </select>   I want to make an option selected, but I want it to be according the ID of the user in this list not the index, so I set the value of each option to the user ID.  How could I make one this options selected when I know just the ID, for example I got ID=5 so I want aUser1 to be selected.

I have a drop-down list with known values. What I'm trying to do is set the drop down list to a particular value that I know exists using jQuery.  Using regular JavaScript, I would do something like:  ddl = document.getElementById("ID of element goes here"); ddl.value = 2; // 2 being the value I want to set it too.   However, I need to do this with jQuery, because I'm using a CSS class for my selector (stupid  client ids...).  Here are a few things I've tried:  $("._statusDDL").val(2); // Doesn't find 2 as a value. $("._statusDDL").children("option").val(2) // Also failed.      How can I do it with jQuery?     Update  So as it turns out, I had it right the first time with:  $("._statusDDL").val(2);   When I put an alert just above it works fine, but when I remove the alert and let it run at full speed, I get the error     Could not set the selected property. Invalid Index   I'm not sure if it's a bug with jQuery or Internet Explorer 6 (I'm guessing Internet Explorer 6), but it's terribly annoying.


Back somewhere between 1995 and 1998 I have watched feature-length animated movie on home video. Sadly, tape was broken and I have never seen last 15-20 minutes. Animation quality was remarkably better than anything on TV at that time, so I think it was relatively new then. I don't remember anything from plot for certain, probably because I was too young to understand any of it (but hey, if it's animated it must be for children, right?).  What I do remember, though:   There were only two main human characters - male and female. I'd say they were in 20s. Female might have been introduced in later part of the movie. If there were other humans, they didn't play significant enough role for me to remember them. There were a lot of androids, all looking exactly the same. They were painted black or dark-grey. Being androids, they were very human-like. I think they had blank heads, as if wearing helmets. I think they had very smooth movements and maybe main characters initially thought that they are humans? Androids had some specific, in-universe name. I think it did end with "-oid". It might have been in a title of movie. Main characters preferred to avoid these androids, rarely engaging in open confrontation. I don't remember any cities, forests, seas or grasslands. Most of the action was out in open air on some desert and/or rocky area, like real-world planet Mars. Art style was realistic. Think of something similar to . Colors were rather dim, with heavy usage of dark orange/red. There was shooting. I think that shooting device had big caliber, like . It shot laser beams or some kind of waves. Humans definitely shot at androids, but I don't remember if androids ever shot back. I think androids were empty inside. Main characters might have discovered that when they shot android for the first time and investigated the body. I think that close to end there was a scene with human(s?) floating in some reddish substance. That might have been a dream, some kind of out-of-body experience or them dying.   So, I remember rather visuals than plot, making it much harder for me to find. I did went through some "100 of best animes" lists and Wikipedia list on robot characters, but couldn't find it. So far I am only sure that it wasn't something from .  Does anyone remember that movie and can name it?

It was a weird sci-fi animated movie I saw only a little bit of it. This is what I recall:   It was old but had color, so I assume it was late 1960s to early 1970s. The animation and style reminded me of  but it wasn't as psychedelic. The setting was an alien planet with all sorts of bizarre creatures. The tech was advanced but not a dominant aspect of the planet's culture. The people lived simple and peaceful. The protagonist is a man with bluish skin like the others. The antagonists were humanoid shaped black robots that shot a beam that would turn people into stone.


From what I’ve seen in other posts, it looks like I entered a typo... Hate to say I’m extremely new to Ubuntu, but hopeful this is fairly simple! Sudo apt-get update E: Malformed entry 9 in list file /etc/apt/sources.list (Component) E:The list of sources could not be read.

I'm relatively new to Ubuntu 16.04, and everything has been going fine until my OS threw this error today.   Below is the source code from /etc/apt/sources.list for line 54:  deb http://archive.canonical.com/ partner   I have tried appending ubuntu after the / and before partner, but this does not seem to work.   Any ideas what else to try? I can't run sudo apt-get update until this is fixed.


I'd like to understand what's the error here. I'm trying to declare a String variable which contains the name attribute of another class like so:       public static void findContact() {         int se = 1;         String nom;         String nomS;         Contact ce;         while (se == 1) {             nom = JOptionPane.showInputDialog("Name of desired contact: ");             int i;             for (i = 0; i <= it; i++) {                 ce = c[i];                 nomS = ce.getName();//here is the error                 if (nomS.equalsIgnoreCase(nom)) {                     System.out.println(c[i]);                 }             }             se = Integer.parseInt(JOptionPane.showInputDialog("Would you like to search for another contact [1]Y [2]N"));         }     }   c, the contacts list was declared as a constant like so[i'll omit unnecessary code]:       private static final Contact c[] = new Contact[100];   and the contacts class was declared like so [i'll show the relevant parts]:  public class Contact {     private String name;     private int phone;     private String mail;      public Contact() {         name = " ";         phone = 0;         mail = " ";     }      public Contacto(String name, int phone, String mail) {         this.name = name;         this.phone = phone;         this.mail = mail;     }      public String getName() {         return name;     }          @Override     public String toString() {         return name + phone + mail;     }   I've tried creating another Contact type variable inside the method:  Contact ce = new Contact();   or  Contact ce = new Contact("",1,"");   To no avail. The worst part is that the code actually compiles and shows what it's supposed to show, it does compare and show the contact as if it worked perfectly but i still get this [My variables are in spanish in the actual code]:   Thanks in advance to any and all reading and helping.  Edit: I have an array filler method:      public static void addContact() {         String nom;         int phone;         String mail;         int se = 1;         while (se == 1 ) {             nom = JOptionPane.showInputDialog("Name of contact: ");             phone = Integer.parseInt(JOptionPane.showInputDialog("Phone number: "));             mail = JOptionPane.showInputDialog("contact's mail");             System.out.println(nom + " " + phone + " " + mail);             Contact con = new Contact(nom, phone, mail);             c[it] = con;             System.out.println(c[0]);             it++;             se = Integer.parseInt(JOptionPane.showInputDialog("Add another contact 1Y 2N"));         }     }   So the array is filled with at least 1 at any given moment.

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 uninstall MikTex because texstudio can't update package automatically. I want to install it again. But I got this error instead when I launch sudo apt-get update: Hit:1 http://pl.archive.ubuntu.com/ubuntu focal InRelease Hit:3 http://pl.archive.ubuntu.com/ubuntu focal-updates InRelease                                                                                Hit:4 http://ppa.launchpad.net/sunderme/texstudio/ubuntu focal InRelease                                                                                Hit:5 http://pl.archive.ubuntu.com/ubuntu focal-backports InRelease                                                                                Hit:6 http://download.opensuse.org/repositories/Ubuntu:/debbuild/Ubuntu_20.04  InRelease                                                                                Hit:7 http://deb.playonlinux.com trusty InRelease                                                                                Hit:8 https://download.docker.com/linux/ubuntu focal InRelease                                                                                Hit:9 http://security.ubuntu.com/ubuntu focal-security InRelease                                                                                Ign:2 https://ftp.gust.org.pl/TeX/systems/win32/miktex/setup/deb focal InRelease            Err:11 https://ftp.gust.org.pl/TeX/systems/win32/miktex/setup/deb focal Release   Certificate verification failed: The certificate is NOT trusted. The certificate chain uses insecure algorithm.  Could not handshake: Error in the certificate verification. [IP: 158.75.62.5 443] Ign:10 https://cvmrepo.web.cern.ch/cvmrepo/apt focal-prod InRelease Hit:12 https://cvmrepo.web.cern.ch/cvmrepo/apt focal-prod Release Reading package lists... Done E: The repository 'http://miktex.org/download/ubuntu focal Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  I tried sudo apt install ca-certificates but it failed. This also doesn't work  The result from there: ~$ sudo ppa-purge ppa:mc3man/trusty-media Updating packages lists E: The repository 'http://miktex.org/download/ubuntu focal Release' no longer has a Release file. Warning:  apt-get update failed for some reason  ~$ sudo apt-get update Hit:1 http://pl.archive.ubuntu.com/ubuntu focal InRelease Hit:2 http://download.opensuse.org/repositories/Ubuntu:/debbuild/Ubuntu_20.04  InRelease Hit:3 http://pl.archive.ubuntu.com/ubuntu focal-updates InRelease               Hit:4 http://ppa.launchpad.net/sunderme/texstudio/ubuntu focal InRelease        Hit:5 http://deb.playonlinux.com trusty InRelease                               Hit:7 http://pl.archive.ubuntu.com/ubuntu focal-backports InRelease             Hit:9 https://download.docker.com/linux/ubuntu focal InRelease                  Ign:6 https://ftp.gust.org.pl/TeX/systems/win32/miktex/setup/deb focal InRelease Hit:11 http://security.ubuntu.com/ubuntu focal-security InRelease               Err:10 https://ftp.gust.org.pl/TeX/systems/win32/miktex/setup/deb focal Release   Certificate verification failed: The certificate is NOT trusted. The certificate chain uses insecure algorithm.  Could not handshake: Error in the certificate verification. [IP: 158.75.62.5 443] Ign:8 https://cvmrepo.web.cern.ch/cvmrepo/apt focal-prod InRelease              Hit:12 https://cvmrepo.web.cern.ch/cvmrepo/apt focal-prod Release Reading package lists... Done E: The repository 'http://miktex.org/download/ubuntu focal Release' no longer has a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  Now I can't install it again. Help?

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


I am still puzzled guys how come itachi died but sasuke still has his eyes but when obito died kakashi lost his sharingan eyes and all the skills it came with.is there something im missing or its something the writers just came up with on the spot

In Chapter 691, after Obito died, Kakashi’s Sharingan faded. Why is it that Kakashi's Sharingan faded, while the Sharingan Danzo had stolen from Shisui and the one Shisui had given Itachi, were still okay even after its original owner had died?


Can watercolor artwork be printed on fabric, noting that the fabric is white? if yes how can it be prepared and if not what options do i have? Thank you

What does it mean to colour separate the artwork for T-Shirt printing? It is normally suggested to use Pantone colours for T-Shirt printing. Is it the Pantone Coated or the Pantone Uncoated? The Uncoated one has more subtle colours and we can't choose brighter shades if the design requires that. What is more appropriate for printing? Can we use gradients in T-Shirt printing or is it suggested to stick to flat colours only?   The reason for asking if gradients were ok was to use it as an option for this design:    I was considering it an option, as it will be difficult to colour separate since the textures are clip masked inside the lion.


My first research paper is due tomorrow and my university does not seem provide students access to Turnitin. There are numerous other plagiarism checkers online but none seem to be reliable.   Are there any services that I can use that is as reliable as Turitin?

Which free online academic plagiarism checker is closest to Turnitin by quality  standard of rigour?  Turnitin features that even somebody plagiarize the context of a passage by use synonyms or simply rephrase the sentence, it is still able to catch the student cheating...  Please notice that Turnitin is not free and some of free software are not rigorous enough or even people called it a joke!


I have a scheduled class which in turn calls a Database.executeBatch to start a batch class. I am trying to make some edits to batch class and I am receiving well known "schedulable class has jobs pending or in progress" error message when saving batch class. Based on below article,    I have   deleted all scheduled jobs that are under Setup -> Monitoring -> scheduled jobs Also made sure that there are no jobs in queued status     .  SELECT ApexClassId, CreatedDate, ExtendedStatus, Id, JobItemsProcessed, JobType, MethodName, ParentJobId, Status, TotalJobItems  FROM AsyncApexJob  WHERE status!='Completed' AND status!='Aborted' AND status != 'Failed'   Above query is returning count as 0.  I have only 1 entry in CronTrigger table where State is "ACQUIRED" and CronJobDetail.Name is null. I tried to call abortjob on this entry but I get an error - Invalid parameter value "000000000000000" for parameter "id") when I run abortjob.  Any idea if this Crontrigger entry is preventing edits to batch class ?

Recently I've been running into issues where deployments were blocked due to a Schedulable job pending or in progress when I'd already cleared the Schedulable job from that class.  Any tips for resolving this issue?  I've had success in the past by querying all CronTrigger objects and aborting the jobs that don't have a status of 'Deleted', but that has the unwanted side effect of cancelling all Dashboard Refreshes as well.  I'm sure there is just a stuck job in there somewhere, but was curious if any of you code heads out there had other ideas ...


Is there a way to automatically know who called a specific function in JS?  Let's say I have this code:  function1() { function2(); }  function2() { console.log('the function who called me is ...' + <magic code here>); }   When function1 calls function2, is there any magic way for function2 to know that function1 called it, without passing any additional parameters?

function main() {    Hello(); }  function Hello() {   // How do you find out the caller function is 'main'? }   Is there a way to find out the call stack?


I want to simulate a block dialog like window.alert(), window.confirm(), or window.prompt() with DIV+JavaScript. It seems easy using a callback function. But I want to block the process while the confirm dialog is shown.   That is to say, I want to define a function like:  var Alert = function(){ balabala };   which returns true or false after I click OK or Cancel.  EDIT:  For now I defined a function called Confirm() and now I have to call it like   Confirm(*callback*);   and in the implementation I show a dialog like confirm and when OK is clicked the callback will be executed. I wonder whether it is possible to rewrite it so that I can call it like   if(Confirm()) {     callback();  } else {     balabala; }

Ok, I'm doing a bunch of RIA/AJAX stuff and need to create a "pretty", custom confirm box which is a DIV (not the built-in javascript confirm). I'm having trouble determining how to accomplish a pause in execution to give the user a chance to accept or decline the condition before either resuming or halting execution. (depending upon their answer)   So here's the general flow of logic I'm dealing with:   User selects an item from dropdown and clicks button. In client-side javascript eventhandler for button, I need to check a (this is the key) SERIES of conditions for the item they chose in dropdown.  These conditions could possibly result in not showing any confirmation at all or possibly only some of the conditions may evaluate to true which means I'll need to ask the user to accept or decline the condition before proceeding. Only one confirmation should be show at a time.   To demonstrate the logic:  function buttonEventHandler() {  if (condition1) {   if(!showConfirmForCondition1) // want execution to pause while waiting for user response.      return; // discontinue execution }  if (condition2) {   if (!showConfirmForCondition2) // want execution to pause while waiting for user response.       return; // discontinue execution }  if (condition3) {   if (!showConfirmForCondition3) // want execution to pause while waiting for user response.       return; // discontinue execution }  ...   }    If anybody has dealt with this challenge before and found a solution, help would be greatly appreciated. As a note, I'm also using the MS Ajax and jQuery libraries although I haven't found any functionality that may already be included in those for this problem.


$\sum_{1}^{\inf}{\phi(n)/n^x}$ Get an closed form expression for the value in terms of x.  Also, is there a closed form for the function $f(x) = \sum_{1}^{\inf}{\pi(n)/n^x}$. If you use PNT you can get some expressions in terms of li integrals but that's probably a dead end and since PNT is only an approximation its not the actual function.

Earlier today I thought I proved that the following series diverged:  $$\sum_{n=2}^\infty\frac{\phi(n)}{n^2}$$  as a result of a misapplication of the prime number theorem. I mistook $\phi(n)$ for $\pi(n)$ in the statement. Is this salvageable? I've been trying to find lower bounds for $\phi(n)$ that I may pass to, but the literature on this is a bit dense for me.  Thanks


I was asked the following question, and while I think I made little progress, I'd like a push in the right direction.  Let $A$ be $n$x$n$ positive definite symmetric matrix with real entries. then for all $x \in \mathbb R^n$, evaluate the integral:  $$\int_{\mathbb R^n}e^{-\langle Ax,x \rangle}dx$$  Hint: Start by assuming $A$ is diagonal and remember that any symmetric matrix is also diagonlizable.  What I did:  I think the hint is good. Assume $A$ is diagonal with the entries $\lambda_1 ,\lambda_2 ,...\lambda_n$, then $\langle Ax,x \rangle=\sum_{i=1}^{n} \lambda_ix_i^2$  So now the integral becomes $$\int_{\mathbb R^n}e^{\sum_{i=1}^{n}\lambda_ix_i^2}dx$$  But what now? can we split integral and integrate by $x_i$ each time?

Let $A$ be a positive definite real $n\times n$ matrix. How can I prove that $$ \int_{\mathbb{R}^n}\mathrm{e}^{-\langle Ax,x\rangle}\text{d}x=\left|\,\det\left(\pi^{-1}{A}\right)\right|^{-1/2}=\pi^{n/2}\lvert\,\det A\rvert^{-1/2}\!, $$ where $\langle\cdot,\cdot\rangle$ denotes the inner product in $\mathbb R^n$, i.e. $\langle x,y\rangle =x^Ty$.


a=2 pt2=3 echo $a 2 echo $pt2 3   How can I use  echo $pt($a)   to print the contents of pt2?  An alternative is  b=pt$a echo $b pt2 echo $[$b] 3

I am trying to do the following in my script:  #/bin/bash -x var1=www var2=www2 var3=www3 var4=www4 for i in 1 2 3 4; do    echo \$var$i done   Obviously, this doesn't work as expected and results in the following output:  $var1 $var2 $var3 $var4   How can I dynamically reference the variables in my loop?


I read that the space of quantum states, i.e. the space of density operators $\mathcal{S}_n = \{ \rho \in H_n : \rho \geq 0, \, \, Tr[\rho]=1\}$ is a smooth manifold of dimension $n^2-1$, without further explanation. Could anyone help me understand why this is the case? Here $H_n$ denotes the space of hermitian matrices: $H_n = \{ A \in \mathbb{C}^{n \times n} : \, A^* =A  \}$, and $\rho \geq 0$ means that the matrix $\rho$ is positive semi-definite.

Let $\mathrm{M}_{d\times d}\left(\mathbb{C}\right)$  denote the set of all $d\times d$-matrices with complex entries. My goal is to show that the set $\mathcal{M}:= \left\{ \rho\in \mathrm{M}_{d\times d}\left(\mathbb{C}\right) \left|\right. \ \rho\geq0 \ , \  {\rm tr}(\rho) = 1 \right\} $ can be endowed with the structure of a smooth manifold (most likely with boundary).   I have proven that $\mathcal{M}':= \left\{ \rho\in \mathrm{M}_{d\times d}\left(\mathbb{C}\right) \left|\right. \ \rho>0 \ , \  {\rm tr}(\rho) = 1 \right\}$ is indeed a smooth manifold. My argument roughly goes like this:   First we notice that $\mathrm{M}_{d\times d}\left(\mathbb{C}\right)$ is a $2d^{2}$-dimensional real vector space and the set $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$ of all hermitian $d\times d$ matrices with complex entries is a $d^{2}$ dimensional real vector subspace. In particular $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$ trivially forms a $d^{2}$-dimensional manifold since it's globally diffeomorphic to $\mathbb{R}^{d^{2}}$.  Next we want to show that the set $\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$ of all positive $d\times d$-matrices (which is a subset of $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$) is open in the relative topology of $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$. Therefor it constitutes a $d^{2}$-dimensional manifold. To see this we can consider the map  \begin{align} f: \mathrm{H}_{d\times d}\left(\mathbb{C}\right) &\rightarrow \mathbb{R}^{d^{2}} \nonumber\\ A &\mapsto \left(\lambda_{1},...,\lambda_{d^{2}}\right) \end{align} which maps a hermitian matrix to its eigenvalues. This map is continuous. Since $\mathbb{R}_{>0}^{d^{2}}$ is an open set in $\mathbb{R}^{d^{2}}$ it follows that the preimage  $f^{-1}\left(\mathbb{R}_{>0}^{d^{2}}\right)=\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$  is also open in $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$. Now consider the map  \begin{align} g: \mathrm{H}_{d\times d}\left(\mathbb{C}\right) &\rightarrow \mathbb{R} \nonumber\\ \rho &\mapsto {\rm tr}(\rho). \end{align} We need to show that 1 is a regular value of g. To do so we pick a $\rho\in g^{-1}(1)$.  Next we choose a curve $\gamma: (-\epsilon,\epsilon) \rightarrow \mathcal{M}$ with $\gamma(0) = \rho$ and $\partial_{t}\gamma(0) = A$ for some $A\in T_{\rho}\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$.  We calculate that  \begin{equation} dg_{\rho}A := \left.\frac{\mathrm{d}}{\mathrm{d}t}\right|_{t=0} {\rm tr}(\gamma(t)) ={\rm tr}(A). \end{equation} Certainly $dg_{\rho}$ is surjective. This proofs the result.  I'm wondering whether this proof can be extended to positive-semidefinite matrices since a positive-semidefinite matrix can be approximated by a sequence of positive definite matrices. I'm however not sure whether the "boundary" that we will obtain is still regular in the sense that it contains no "sharp edges".   I would be more than happy for some suggestions and ideas.


Could anyone please help me find limit? $$\lim_{n\to\infty} \left(\frac{\left(1 + \frac{1}{n}\right)^n}{e}\right)^n$$ Thank you

We know that $\lim_{n\rightarrow\infty}(1+\frac{1}{n})^n=e$ and so I thought the approach to evaluating the limit in the question would be to just use this fact and substitute it into the numerator. This approach would tell us the above limit evaluates to $1$. However, that does not seem to be the correct limiting value. In fact, it evaluates to $\frac {1}{\sqrt{e}}$. Why is this so?


I am doing a self-study on Exponential Distribution and noted an exponential on my text giving that:  CDF of Exponential Distribution $$ F(x) = 1 - e^{-λx} , $$ PDF of Exponential Distribution $$ f(x) = λe^{-(λx)} . $$ However, I was wondering on what conditions do I use what?  From what I understand, if I was trying to find the time between consecutive events within a certain period of time, I may use the CDF. However, I am unable about PDF.  Appreciate any advice please.

This may be too much of a general question but I hope I can find help here. I am starting a RA job in my university and my topic will be related to Internet Traffic Analysis. I am fairly new to the world of analysis but I guess in the world of research this is what I have to do a lot of.  I've been through a few papers and in a lot of them I find they use Probability Density (PDF), CDF, CCDF etc to explain the results they've obtained. For example, PDF of user session duration, CDF of bytes transferred each day etc. I have taken probability and statistics class so I understand what they are but I am still confused to the cases in which such representation would be chosen.  So, if there is anyone out there who does such graphs and analysis (in any other topic in general or this) could you tell me simply in what situation would I use one or the other of these representations


As the title says, does Shyvana's q proc  passive  twice? Since her q essentially counts as two auto attacks (instant kill wards for example), then would each "auto" from her q proc Hydra?

Twin Bite - Shyvana strikes twice on her next attack.  Dragon Form: Twin Bite cleaves all units in front Shyvana. Shyvana strikes twice on her next attack, dealing (+0.8/0.85/0.9/0.95/1.0) physical   damage on the second attack.  The bonus damage is equal to 80/85/90/95/100% of Shyvana's Attack Damage.`  Dragon Form: Twin Bite cleaves all units in front Shyvana. Cost No Cost Range 0   does this mean, Wit's End or other on-hit items will proc twice?  To Mind jumps: Black Cleaver Wit's End Executioners Calling BotRK    and the list goes on...


So let's say you had infinite time and energy. You have a hashed string of some sort. Because you have infinite time and energy, you can produce a collision(or the original value) easily enough. But, there is a problem. The hashed string was hashed an unknown amount of times. (ie, it may have been produced by sha256(sha256("foobar")) or by sha256(sha256(sha256(sha256("foobar"))))).   You were given a hint by your adversary though. They give you (say) 10 strings, of which one is the initial value that is hashed.   Is it possible to determine with absolute certainty that you chose the correct string? Is it possible that hashing "foobar" recursively an infinite amount of times will eventually yield any arbitrary hash value?  Although my question is about SHA256, I'd be equally curious of other hash algorithms as well

There are many cases in maths where doing the same thing over and over again will bring you closer to a value. Derivation of polynomials is the striking example: no matter what you start with, you end up with 0. In a series expansion, the longer you continue the sequence the closer you get to the real value.  This concept applies in areas other than math (Wikipedia's everything-leads-to-philosophy phenomenon, for example). It's a little unrelated but it just proves the concept.  Hashing algorithms are just special math. Following logically, hash entropy supposedly decreases the more you hash a value. So is there a point at which any input value will give the same hash as any other?  (Let me just specify that we're not re-injecting any new data every time we hash, as if we're trying to increase the security of the hash by salting and re-hashing. It's strictly a matter of md5(md5(md5(... if that's the algorithm we're using.  I can see some problems with this already. Algorithms like md5 are designed to change their output radically when the input changes only by one bit of information. So even if a common hash for two values appears along the way, it itself will start changing. But then, does the fact that the output appears to be very different actually mean the possibilities are still many?


What's the name of the "=>" operator  (e.g in C# linq .Select(x=>x.Prop1) )  It might not even be an operator.  Does it have a different name in different languages (C# vs JavaScript)  Tagging as operator / C# / javascript - Not sure where this fits in...

I very rarely meet any other programmers!  My thought when I first saw the token was "implies that" since that's what it would read it as in a mathematical proof but that clearly isn't its sense.  So how do I say or read "=>" as in:-  IEnumerable<Person> Adults = people.Where(p => p.Age > 16)   Or is there even an agreed way of saying it?


After upgrading my pc from ubuntu 14.10 to ubuntu 15.04 my pc can no longer detect headphones and can only play through the speakers. how can i fix this?

I updated to Ubuntu 15.04 from Ubuntu 14.10 a few days ago, and now my Logitech G230 headphones don't receive any sound. How can I fix this? PulseAudio Volume Control detects my headphones, and says they're working, but no sound comes through.  EDIT: Using alsamixer worked at first, but now it doesn't, and I get frequent bursts of static through my headphones now.


For the fifth year in a row I flew approximately 60 times. Most of my flights are within Europe, so an average flight is quite short (~1000 km, ~2 hours). I am concerned about negative health effects caused by cosmic ray radiation.  The  suggests that I receive ~7-9 µSv per 2 hour flight. This means adding additional ~0.5 mSv to my annual radiation dose. Background radiation in my area of 1 mSv/year and a few medical x-rays can easily add up to 3-4 mSv annual dose.  According to BSS/EU, the safe yearly radiation exposure for the general public is 1 mSv.   An example of one of my flights:     Do my calculations make sense? Should I be concerned about increased cancer risk? Are there any possible negative health effects not related to radiation?  What are some articles/papers on the topic that you'd recommend?

You often hear people object to being scanned because of the "" argument. I find this always quite amusing from people just being exposed to higher radiation levels during the average airplane flight. I once read a article on the levels of being exposed to radiation in everyday live, but I lost the article. I remember that the exposure in planes was quit substantial. Somewhere in the order of one body scan is equal to 10 minutes of your average transcontinental flight.   So my question is, to how much more radiation are you really exposed while traveling in an airplane, compared to staying on the ground?


I have these symbols which I am quite sure they are chinese characters.  &#26053;&#34892;&#26178;&#65292;&#25105;&#29983;&#30149;   Please anyone know what kind of unicode is this with &# and semicolon please? And how can I turn it into chinese characters string or normal unicode in Python please?

I'm doing some web scraping and sites frequently use HTML entities to represent non ascii characters. Does Python have a utility that takes a string with HTML entities and returns a unicode type?  For example:  I get back:  &#x01ce;   which represents an "ǎ" with a tone mark.  In binary, this is represented as the 16 bit 01ce.  I want to convert the html entity into the value  u'\u01ce'


Here is what I am doing: I want to find which zip files includes this number with number itself for example i want the result be like this :  7505857289 AIRCDR   where the number is my search result and AIRCDRis zipfilename that contains this number among 100000 files

I wish to write the result of these below conditions in a file:    in a specific folder, I have many tar.gz files. each tar.gz file contains .dat file in sub folders. I wish to get the full path of these .dat files, if I find in it a specific word (ERROR24).  all this without extracting the tar.gz files   I have found and tested the below one that writes in a file the result, but I don't how to look in a tar.gz file.  grep -rlw --include="*.dat" -e "ERROR24" /home/tests/logs > /home/files/data/result/listErrors.txt   Can you please help update the previous one in order to get the same result but searching in tar.gz files?


We know that you can do flexible search for multiple destinations for a specific date with a fixed source airport. For example, if you want to fly somewhere for a weekend from London, but don't care where exactly and want to see the prices, you can use either Google Flights or SkyScanner, type "Europe" as a destination and see the possible destinations and prices.  Is it possible to do the same search with fixed destination airport? What I mean is that I want to be in Heathrow on 1st, and I want to know from which airport around Europe it would be the cheapest to fly there on this particular date? So kind of "Europe" - > "LHR" search?  Edit: I know it is possible to do broad search from a source airport to multiple destinations. However I'm looking for the opposite - a search from many origins spawning multiple countries to one specific destination airport.   To be very specific: I want to type in "Europe" into the origin (not the "list of a few airports)", and "SFO" into the destination (not the "USA"), and see the flights with prices for the particular date.  Neither Kayar, nor ITA Matrix, nor Skyscanner, nor Google Flights seem to allow that.

Many flight search engines allow you to pick a departure airport and search for flights to anywhere. E.g.  gives you a nice map with prices next to destinations for a set of dates and an origin you selected. We covered this question widely in  here on our site.  I want to have the reverse, i.e. I know my dates and my destination (for a one-way flight) and I want to know from where it is cheapest to fly there. Is there any flight search engine out there to achieve this?  Google flights does not do this, they pre-compile the "from"-field if I try to leave it empty. I know I could use  with a wide range of departure airports but that does not give me low-cost carriers and I do not trust the matrix results for such a wide range of parameters anymore.  Edit: It has been asked in comments why I would want such a feature. Well currently I'm planning my summer vacation and I would like to spend one week traveling around basically anywhere in that area before I have to go to a specific location at a specific time. One of the main price and convenience factors for me is that final flight so I would like to optimize it first. I'm sure I'm not the only one with that kind of constraints.


Sorry everyone, I made a mistake in my question itself for my previous posting:   It should have been:  If A∩B∩C=∅, then A∩B=∅,A∩C=∅ or B∩C=∅. Prove or show counterexample.  So false, if I take A={1,2}, B={2,3}, and C={1,3}. then A∩B∩C=∅, but A∩B={2},A∩C={1},B∩C={3}. Thus leads to contradiction. Is this correct?  By the way, can someone explain to me the difference in the prove when the question is or and and.

Show that $A∩B∩C= ∅$ is only true when  $A∩B = ∅, A∩C = ∅$ or $B∩C = ∅$ or show a counterexample.   My answer: True, Let set A={a,b,c,...}, set B={1,2,3,...} and set C={-1,-2,-3...}. Then there is not common elements in A, B or C. Thus, A∩B∩C= ∅. A∩B = ∅, A∩C = ∅ or B∩C = ∅.  Is my prove right?


I'm not familiar with creating .bat files, but I want to create a file to deactivate/disable a network device    This is in win7. I have googled some similar problems, but nothing to solve this. pls help.

Is there a way to enable/disable a wireless network interface via the command line (so I can put it in a bat file)?  When I'm in the office I use a wired connection, but Windows still occasionally bugs me about my wireless connection not being connected (even though I turned off the option for notifying me when there's no connectivity).  I'm guessing the only way to stop it from bugging me is to disable the interface, but I'd rather not have to go into the network settings every time I need to do so.  I'd like to set up a bat file or a shortcut that I can use to enable/disable the wireless (preferably a single one that toggles the current state), and then just set up a keyboard shortcut for that.  I just have no idea how to do so from the command line.


Let $V$ be an infinite dimensional vector space and $B$ be a basis. I would like to prove that every element of $V$ has a unique representation as a linear combination of elements of $B$.   I can visualize why this is true (heuristically: take the first representation minus the second and get linear dependence), however I seem unable to do the technical work. It is tricky. The finite dimensional case is trivial and it can't be generalized.  Can someone show me how to do this?

In a book I am reading the author states without proof that in an $n$-dimensional vector space $X$, the representation of any $x$ as a linear combination of a given basis $e_{1},e_{2},...,e_{n}$ is unique. How to proof that?


Consider an algebraic extension $K$ of $\mathbb{Q}$.  The degree $[K:\mathbb{Q}]$ of $K$ is defined as the dimension of the extension considered as a vector space.  Now, let $\overline{\mathbb{Q}}$ be algebraic closure of $\mathbb{Q}$.  My question is,     Can we built an arbitrary algebraic extension $F$ of $\mathbb{Q}$ such   that $[\overline{\mathbb{Q}}:F]=n$, for any $n\in \mathbb{N}$? How?

Let $\mathbb R$ be the field of real numbers. Its algebraic closure, the field $\mathbb C$, is a finite extension of $\mathbb R$, which has degree 2.   Are there other examples of fields (not algebraic closed) such that its algebraic closure is a finite extension?


I have created a carousel for which I have included a play/pause button. I am using bootstrap and have added the following code.  <button class="btn btn-danger btn-small" id="carousel-button">                                              </button>   Jquery:  $(document).ready(function() {             $("#carousel-button").click(function() {                 if ($("#carousel-button").children("span").hasClass('fa-pause')) {                     $("#mycarousel").carousel('pause');                     $("#carousel-button").children("span").removeClass('fa-pause');                     $("#carousel-button").children("span").addClass('fa-play');                 } else if ($("#carousel-button").children("span").hasClass('fa-play')) {                     $("#mycarousel").carousel('cycle');                     $("#carousel-button").children("span").removeClass('fa-play');                     $("#carousel-button").children("span").addClass('fa-pause');                 }             });         });   I do not understand where it is getting wrong and why the button won't change after clicked.

How can I change the class of an HTML element in response to an onclick or any other events using JavaScript?


I'm reading a science fiction book where a character is on a rotating space station orbiting Mars.  She is running opposite to the spin at a speed where Mars is stationary overhead.  Would this cancel out the artificial gravity caused by the rotation?  If so, what would happen to her?  EDIT - I did look at the answer to a similar question after sammy suggested it, and while it is the same question, I still wonder about what would happen. If you're running against the rotation, you would probably begin to float.  But then the moving air would catch you.  I assume that you would then fall back to the "floor".  Does that seem sensible?

I've recently been contemplating things like artificial gravity in a rotating space ship (for example, the ) and learning about the Coralis effect and other interesting fictitious forces that appear in rotating reference frames.  It occurred to me that, if you were living on a space station spun for artificial gravity, it might be possible to become weightless in such an environment by travelling fast enough against the spin of the ship. My friend, who I was discussing this with, thinks otherwise, that you would actually be under more g's as you tried to gain the speed to lift off from the inner edge of the ship.  In terms of concrete numbers, say the ship is 4 kilometers in radius (as an O'Neill Cylinder would). At this size, the rate of rotation to generate 1g in centrifugal force (the artificial gravity) is under 0.5 rpm. If a vehicle travels on the inside of the cylinder against the spin fast enough, eventually the vehicle would cease moving when looked at from a static reference frame. I would think at this point, the vehicle could simply push off from the edge of the cylinder and float towards the center of the station. Is this correct?  Furthermore, would this method of "getting into air", as it were, be easier than it would be to counteract real gravity on Earth (with things like planes that generate lift with their wings)?


If newtons law applies without pseudo forces then we're in an inertial frame. So theoretically we've an inertial frame. What about practically finding one? Earth is not, probably neither the sun. Then where can I find a place to be inertial?

Is there any true  in the universe?  Newton's first law states that an object at rest remains at rest, and an object performing uniform motion performs uniform motion, until and unless acted upon by an external force, if viewed from an inertial frame. It is the definition of an inertial frame of reference. And Newton's second law states that the net external force acting on a particle equals its mass times its acceleration. Thus we need to have an inertial frame in order for Newton's 1st and 2nd laws to be applicable.  Scientists claim that Earth is an inertial frame, either the  frame or the  frame.  Why is that? Earth's different parts have different accelerations when it performs rotational motion about its axis. Now you may say that Earth's axis is inertial, but the Earth is also revolving around the Sun. Thus Earth's frame should be non-inertial.  Even supposing that earth's frame is inertial, then it means that rest of the universe is non-inertial, because only a frame that moves with constant velocity with respect to an inertial frame is also an inertial frame and according to various scientific experiments there is no other matter in this universe which satisfies that criterion. Now you may say that earth is an approximate inertial frame, but still, my question is: is there any perfect inertial frame in the universe where Newton's laws are exactly applicable?


If someone asks me the question     Do you want to come to my house?   If I say yes- I'm accepting their offer. If I say no- I'm declining their offer... simple.  If someone instead asks     Do you not want to come to my house?   It feels weird to answer.  If I say yes- I could be agreeing with them "Yes, I do not want to come to your house", But it also makes sense to say "No, I do not want to come to your house."...  Can this kind of question simply not be answered in a "yes" or "no" without ambiguity?      A: "I'm tired today..."   B: "Do you not want to play football then?"   A: "Yes" and "No" Have the same meaning!

I faced a problem to answer a negative question, for example, when someone asks you:      Don't you have any money?   It's a yes/no question but how should one answer the question without ambiguity?  When you answer "yes", does it mean "yes, I don't have any money"? or the other way "Yes, I do have money"? the questioner may think you are agreeing to the negative, that yes, you do not have any money.  I know it's better to answer with "on the contrary" but is it possible to answer yes or no?


I have a simple method:  internal void run() {     foreach (string file in Directory.GetFiles(Path).ToList()         .Where(x => DateTime.Today.Subtract(File.GetCreationTime(x)).Days > NumberOfDays))     {         File.Delete(file);     } }   Is it possible to get rid of the foreach statement?

I have an Enumerable<T> and am looking for a method that allows me to execute an action for each element, kind of like Select but then for side-effects. Something like:  string[] Names = ...; Names.each(s => Console.Writeline(s));   or   Names.each(s => GenHTMLOutput(s));    // (where GenHTMLOutput cannot for some reason receive the enumerable itself as a parameter)   I did try Select(s=> { Console.WriteLine(s); return s; }), but it wasn't printing anything.


I have IPTABLES newly set up on my Debian Squeeze server and I have IP masquerading and port forwarding working successfully with it, however if I type into the URL bar my WAN IP or DynDNS hostname, I get a connection error. With previous consumer routers, if I had gone to , it would load 10.0.0.3:80 as specified below. This works externally (tested using a 3G phone) but not internally (using any internal browser). This is the same for all forwarded ports. I'm trying to get port forwarding to work internally as well.  If anyone knows the correct incantation(s) for this, it'd be greatly appreciated. I've tried searching Google but am unsure of the correct search terms for the issue.  My configuration is as follows:  # Generated by iptables-save v1.4.8 on Thu Apr 14 15:58:27 2011 *mangle :PREROUTING ACCEPT [1216168:676166344] :INPUT ACCEPT [2375:260404] :FORWARD ACCEPT [1213765:675875465] :OUTPUT ACCEPT [1930:203384] :POSTROUTING ACCEPT [1215695:676078849] -A FORWARD -o ppp0 -p tcp -m tcp --tcp-flags SYN,RST SYN -m tcpmss --mss 1400:65495 -j TCPMSS --clamp-mss-to-pmtu  COMMIT # Completed on Thu Apr 14 15:58:27 2011 # Generated by iptables-save v1.4.8 on Thu Apr 14 15:58:27 2011 *filter :INPUT ACCEPT [2375:260404] :FORWARD DROP [0:0] :OUTPUT ACCEPT [1930:203384] -A FORWARD -i ppp0 -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -i eth0 -o ppp0 -j ACCEPT  -A FORWARD -d 10.0.0.8/32 -p tcp -m tcp --dport 80 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.3/32 -p tcp -m tcp --dport 22 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.8/32 -p tcp -m tcp --dport 1723 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.8/32 -p udp -m udp --dport 1723 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.3/32 -p tcp -m tcp --dport 21 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.3/32 -p tcp -m tcp --dport 45631 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.3/32 -p tcp -m tcp --dport 56630 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  -A FORWARD -d 10.0.0.3/32 -p udp -m udp --dport 56630 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT  COMMIT # Completed on Thu Apr 14 15:58:27 2011 # Generated by iptables-save v1.4.8 on Thu Apr 14 15:58:27 2011 *nat :PREROUTING ACCEPT [5529:468229] :POSTROUTING ACCEPT [2335:258730] :OUTPUT ACCEPT [21:1367] -A PREROUTING -i ppp0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.0.0.8:80  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 22 -j DNAT --to-destination 10.0.0.3:22  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 1723 -j DNAT --to-destination 10.0.0.8:1723  -A PREROUTING -i ppp0 -p udp -m udp --dport 1723 -j DNAT --to-destination 10.0.0.8:1723  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 21 -j DNAT --to-destination 10.0.0.3:21  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 45631 -j DNAT --to-destination 10.0.0.3:45631  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 56630 -j DNAT --to-destination 10.0.0.3:56630  -A PREROUTING -i ppp0 -p udp -m udp --dport 56630 -j DNAT --to-destination 10.0.0.3:56630  -A PREROUTING -i ppp0 -p tcp -m tcp --dport 443 -j DNAT --to-destination 10.0.0.3:22  -A POSTROUTING -o ppp0 -j MASQUERADE  COMMIT # Completed on Thu Apr 14 15:58:27 2011

This is a  about Hairpin NAT (Loopback NAT).   The generic form of this question is:  We have a network with clients, a server, and a NAT Router. There is port forwarding on the router to the server so some of it's services are available externally. We have DNS pointing to the external IP. Local network clients fail to connect, but external work.   Why does this fail? How can I create a unified naming scheme (DNS names which work both locally and externally)?   This question has answeres merged from multiple other questions. They originally referenced FreeBSD, D-Link, Microtik, and other equipment. They're all trying to solve the same problem however.


If a polynomial $f(x)>0 $ for all real values of $x$, then $f(x)$ is sum of squares. Why is this true ? I understand that the roots of this $f(x)$ will be complex and hence will exist as   conjugate pairs ( It is to be assumed that the $f(x) $ has real coefficients).

Let $P\in\mathbb{R}[X]$ be a positive polynomial.  I want to show that there exists $A,B\in\mathbb{R}[X]$ so that $P=A^2+B^2$    $\displaystyle P=a\prod_{k=0}^q(x-a_k)\prod_{k=0}^{2p}(x-b_k)=a\prod_{k=0}^q(x-a_k)\prod_{k=0}^p(x^2-2\Re(b_k)+|b_k|^2)$ where $a$ is the leading coefficient, $a_k$ are the real rooks, $b_k$ are the complex roots.  What can i do now ? I know that the identity $(a^2+b^2)(c^2+d^2)=(ac-bd)^2+(ad+bc)^2$ should come in handy, but I can't figure out :  1) How to show that the product real roots is a square  2) How to use the above identity for the complex roots.  If I can solve those two points, then I can solve the problem.


How do I go about replacing one character for another and then another character for another in one line and printing the result?  As an example, consider the following code:  string="1 33 4 a" echo ${string// /_} #prints 1_33_4_a   Now, I'd like to replace back underscores for spaces so I tried:  echo ${${string// /_}//_/ }   But this yields the error "bad substitution".  I know how to do it with variable assignment, I do not want that. I want do it in just one line, without using sed and as portable as possible.  This is just a challenge to myself which will hopefully be instructive.

To print part of the string, replace , with . I use command:  echo "${q:16:6}" | sed 's/,/./'   Is it possible to use something like:  echo "${q:16:6/,/.}"   because it does not work?


I have a ul with the following elements:

Home

About Me

Work

Contact

Blog

   I'd like to reorder the Home element and place it in the middle in certain situations.  When viewing this in a smaller screen, the list will be rendered vertically, following the order specified in the markup.  However, when viewing on a larger screen, the list will be horizontal, and Home will be in the middle (between Work and Contact).  Is this possible to do purely in CSS? or will I need to use JS or JQuery to reorder the
 elements?

How would I go about reordering divs without altering the HTML source code?  example, I want divs to appear in order #div2, #div1, #div3, but in the HTML they are:

   Thanks!


In a grammar test I did, the following sentence was to be corrected: "I first spotted the turtle playing tag in the yard." It clearly contains a misplaced modifier. The correction suggested was to place the participial phrase at the beginning of the sentence ("Playing tag in the yard, I first spotted the turtle"). Could you, instead, place a comma after turtle? "I first spotted the turtle, playing tag in the yard." Based on what I've read about the placement of participial phrases, there's nothing wrong with it, but it looks and sounds strange to me. "I first spotted the turtle while I was playing tag in the yard" seems preferable to me.

I am having a debate with someone about possible interpretations of a sentence and we have come to a stalemate. The sentence is as follows:      "I'm at home eating vegan cheese in my underpants and singing Bushes   of Love."   The other party argues that my sentence technically says that I am eating vegan cheese which is inside my underpants, when the intended meaning was that I am eating vegan cheese while wearing underpants.   My argument is that his interpretation of the sentence makes no sense, but I can't quite find an actual rule to refer to. I could see it making more sense if I had an article in front of vegan cheese, like "I'm at home eating the vegan cheese in my underpants and singing Bushes of Love".   But as it is without an article if I did intend to say that the vegan cheese was in my underpants, the way I said it would sound very wrong. It seems to me that without an article in front of vegan cheese it was used as a mass noun, uncountable and therefore interpreting it as being a countable chunk of vegan cheese that could be in anything in any subsequent part of the sentence seems wrong.   His argument is that the problem is in the ordering - that while with some common sense my actual meaning might be clear, the sentence was grammatically incorrect and I technically said that the vegan cheese was in my underpants because I should have said "I am in my underpants eating vegan cheese".  Is there a rule I can refer to when it comes to accurate ways to interpret this sentence? Which one of us is correct? Could the vegan cheese really be in my underpants?     Research I have done:  My attempts to find a concrete rule that might be relevant to this scenario led me to the following resources. To me none of these resources suggested that my sentence was technically incorrect. However, because I still was not sure what specific rule I could reference for him or if I was missing a specific rule proving me wrong our debate continued. This is why I decided to ask the question here.   Cambridge Dictionary on adverb positioning in sentences:  Grammar Quick and Dirty Tips on when to use articles in front of nouns, and mass nouns:  Linguapress on word order and sentence structure in English:  Transparent Language on word order in Russian (Russian is my first language and the other party suggested in passing that what he considered my mistake might be related to different word order conventions in non-English languages):


$$x=A\cos(\omega t)+B\sin(\omega t )\equiv\mu \cos(\omega t+\phi)$$  I'm thinking it must have something to do with the double angle forumla. Any help?

If you take a linear combination of the cosine and sine function, then the result is , but with a new amplitude and phase shift. $$a \cos(\theta) + b \sin(\theta) = A \cos(\theta + \theta_0)$$ This is one of those facts which I've always felt should be more obvious to me than it is. I can't help feeling that I might be missing out on some good "conceptual reason" for this to be true. I did a bit of thinking about it today and I came up with the following explanation which I'm not particularly satisfied with. I feel like there should be some perspective on this which renders the fact obvious.      Multiplying the polar equation $r = 2a \cos(\theta) + 2b \sin(\theta)$ by $r$ yields $x^2+y^2 = 2a x + 2by$. Rearranging terms and adding $a^2 + b^2$ to both sides gives $x^2 - 2ax + a^2 +y^2 -2by + b^2 = a^2 + b^2$ which is identical to   $$(x-a)^2 + (y-b)^2 = a^2 + b^2$$   which we recognize as the equation for the circle with centre at $(a,b)$ and passing through the origin. This hints that $r = 2a \cos(\theta) + 2b \sin(\theta)$ should define a parametrization of this circle and, indeed, this holds. This circle can be rotated about the origin so as to have its centre on the $x$-axis. Such a circle will have the simpler equation   $$r = D \cos(\theta) $$   where $D=2(a^2+b^2)$ is the diameter of the circle. In polar coordinates, performing this rotation amounts to introducing a phase $\theta_0$. In fact $\theta_0$ is an argument for the point $(a,b)$.    Note I'm not really looking for rigorous proofs of this fact, more like interpretations, really.


I work for a company which is behind on my salary.  The company might file for bankruptcy: how do I claim my salary before then?   This question is different from other postings. We are discussing how to get wages for employees before the company files for bankruptcy.

I work as an employee for a contracting firm which supplies IT labor resources for their (or) to another contracting firm's clients.   As there is a 45 day holding period for the contract firm which i'm employed to get paid, that delays my paycheck.  Meaning of 45 days holding period is, I worked for first 45 days without getting paid. I received first 15 day paycheck after completing 45 days. Next paycheck will be on the 30th day which will be following 15 days of pay. So, there is always a 45 day pay behind.  My concern or clarification is " What if my employer filed bankruptcy? " - If that's the case, will i ever get paid for those delayed 45 days of my pay.


Whole pre-cooked ham served on Christmas Day.  Been meaning to make pea soup with bones but it now Jan. 10.  The ham still smells fine, not slimmey. Should I use it?

How do I know if a given food or ingredient I have is still good, or if I should discard it?  How can I best preserve a food or ingredient?     This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.


I have some strange problem with a very simple script. I am setting LD_LIBRARY_PATH for a library. When I type this command in terminal:  export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/some/path echo $LD_LIBRARY_PATH   Output from echo showed the linker path is correctly added. But when I put the exact same command into a .sh file:  #!bin/bash export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/some/path   After execution, output from echo showed the linker path is not added. The script has been set to executable, and executed from correct directory. Could someone let me know what may have gone wrong? Thank you!

I have multiple Amazon EC2 accounts and want to quickly be able to switch variables, such as $EC2_HOME, using a script.  I have have a shell script set up like this:  #!/bin/sh export EC2_HOME=/home/me/.ec2 echo $EC2_HOME   When I run the script I know that EC2_HOME is set, but I thought that using export would make the variable stick around after the script completed. It does not, as running echo $EC_HOME does not show anything.  I know this must be very rudimentary Linux scripting knowledge, but I don't know it. I tried looking for related questions without luck - so my apologies if this is a duplicate.


class PointInPlane {     public float x;     public float y;      static class CircleInPlane {         public static float r;           public static float xcentr;         public static float ycentr;          static void solve(PointInPlane a, PointInPlane b, PointInPlane c) {             float A = (b.y-a.y)/(b.x-a.x); //geting NullPointerExeption              float B = (c.y-b.y)/(c.x-b.x); //probably will get in all next steps             xcentr = (A*B*(a.y-c.y)+B*(a.x+b.x)-A*(b.x+c.x))/(2*(B-A));             ycentr = A*(xcentr-a.x)+a.y;             r = sqrt((pow((a.x - xcentr), 2) + pow((a.y - ycentr), 2)));          }     } }   So   IDK how I can handle this problem. I'm getting NullPointerException when declare float A. I think the problem is that I'm using fields from one class in another or trying to use PointInPlane objects a, b and c with null fields. How this problem could be solved?

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've been trying to understand what means "statistically adjusted" when comparing two variables.  For example, when computing the odds ratio for a death after surgery in two hospitals, we compute the odds of death in one hospital, to the odds of death in the other hospital.    But, then let's say we want to "statistically adjust" (as the literature likes to call it)  for other variables.  For each variable we "statistically adjust" for, we will multiply the number of odds ratios by 2.    For example, we "statistically adjust" for whether or not the patients are healthy.  This would mean that we would have two odds ratios:   odds ratio for the patients in good health odds ratio for patients of poor health   Then lets say we adjust for patients of age >50 and patients of age < 50.  Then, we have a total of 4 odds ratios, which is the cartesian product of age, and health.  How do I end up with one odds ratio comparing death rates in the two hospitals?    A resource that attempts to explain this is here:  .  It says that a statistician "will tell you that the odds ratio has been statistically adjusted to incorporate the effect of patient condition at the time of surgery, and is now 1.14".  I do not understand how one value, 1.14, is able to summarize everything about multiple odds ratios.  Thanks for helping me.

Here is the article that motivated this question:   I liked this article, and it nicely demonstrates the concept of “controlling for other variables” (IQ, career, income, age, etc) in order to best isolate the true relationship between just the 2 variables in question.    Can you explain to me how you actually control for variables on a typical data set?      E.g., if you have 2 people with the same impatience level and BMI, but different incomes, how do you treat these data?  Do you categorize them into different subgroups that do have similar income, patience, and BMI?  But, eventually there are dozens of variables to control for (IQ, career, income, age, etc)  How do you then aggregate these (potentially) 100’s of subgroups?  In fact, I have a feeling this approach is barking up the wrong tree, now that I’ve verbalized it.  Thanks for shedding any light on something I've meant to get to the bottom of for a few years now...!


I am curious to know if the Community user really pokes unanswered questions.   Community User profile says:     Randomly poke old unanswered questions every hour so they get some   attention   In my past experience I have seen Community poke questions which have a answer but it was not accepted. I have never seen a poke by Community which has no answer (not even unaccepted one). Am I missing something?  I believe as one of the prime objective of Community User is to poke unanswered questions. I do not want to bump my questions or any specific question. I am curious to know why Community User does not seems to poke question having no answer at all?

What can cause a question to be "bumped" to the first page in the Active tab of a Stack Exchange site? (Changing the "Last Active" date.)  .


I have been trying to implement multiple linear regression from scratch after implementing it using sklearn. The values predicted using sklearn is very accurate whereas the values predicted by the code which I have coded from scratch is not so much accurate. This is the dataset that I am using (I have provided the entire dataset in my Github link mentioned below along with the source code of my implementation)  I am predicting profit of an organisation by seeing the 4 independent variables. Notice that we also  have a categorical value here, on which I have done 1 hot encoding, and I have also scaled all the data. I am using gradient descent to reach the optimal values for slope for the independent variables. The  function I have written for gradient descent updation is as follows. #building the model  #lets start with a random value of m and c  m_1=0 m_2=0 m_3=0 m_4=0 m_5=0 m_6=0  c=0  l=0.0001 #l is the learning rate    n=float(len(X_train)) # n=number of training data, we are converting it to float since we will need to divide n  mse=[]  #we are creating a list for storing mean square errors for each iteration so that we can plot it  for i in range (0,20000):     Y_pred=m_1*X_train[:,0:1]+m_2*X_train[:,1:2]+m_3*X_train[:,2:3]+m_4*X_train[:,3:4]+m_5*X_train[:,4:5]+m_6*X_train[:,5:6]+c          mse.append(numpy.sum((Y_pred-Y_train)**2)/n)     D_m_1= (2/n) * sum(X_train[:,0:1]*(Y_pred-Y_train))     D_m_2= (2/n) * sum(X_train[:,1:2]*(Y_pred-Y_train))     D_m_3= (2/n) * sum(X_train[:,2:3]*(Y_pred-Y_train))     D_m_4= (2/n) * sum(X_train[:,3:4]*(Y_pred-Y_train))     D_m_5= (2/n) * sum(X_train[:,4:5]*(Y_pred-Y_train))     D_m_6= (2/n) * sum(X_train[:,5:6]*(Y_pred-Y_train))     D_c= (2/n) * sum(Y_pred-Y_train)          #Andrew Ng has not taken 2/n but instead 1/n as his cost function is multiplied by 1/2 to reduce complexity          m_1=m_1-l*D_m_1     m_2=m_2-l*D_m_2     m_3=m_3-l*D_m_3     m_4=m_4-l*D_m_4     m_5=m_5-l*D_m_5     m_6=m_6-l*D_m_6     c=c-l*D_c            plt.plot(mse)  #see the plot below, we can see the point where MSE stabilises. Run the above loop till that point and take MSE  This is the function that I have written, and in the other code where I have used sklearn library the code looks like this, #now we will fit the linear regression model  from sklearn.linear_model import LinearRegression import matplotlib.pyplot as plt  regressor= LinearRegression()  regressor.fit(X_train,Y_train)  #predicting the test results Y_pred=regressor.predict(X_test)  But there is a significant difference between the predicted value of the 2 code and as obvious the sklearn is producing good results. I am not getting why the code which I have written from scratch is having low accuracy. I am providing the dataset as well as the code (where I have written the gradient descent) below. Link to code and dataset-->

I am taking the Machine Learning courses online and learnt about Gradient Descent for calculating the optimal values in the hypothesis.  h(x) = B0 + B1X   why we need to use Gradient Descent if we can easily find the values with the below formula? This looks straight forward and easy too. but GD needs multiple iterations to get the value.  B1 = Correlation * (Std. Dev. of y/ Std. Dev. of x)  B0 = Mean(Y) – B1 * Mean(X)   NOTE: Taken as in   I did checked on the below questions and for me it was not clear to understand.      The above answers compares GD vs. using derivatives.


Sometimes you just want to let out some steam, and troll about some technology or software. You are not looking for any answers, but for users with similar experiences and interesting stories. So why not create a separate discussion site (trolling.stackoverflow.com?), where you could ask questions like "why do you hate technology X" or "What are the stupidest bugs you encountered in X"?

Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com.


Find the limit of: $$\lim_{x\to 0}\frac{x^2 \sin 1/x}{\sin x}$$  Answer: Since $x^2 \sin\frac{1}{x}$, so $-x^2\leq x^2 \sin\frac{1}{x}\leq x^2$, thus $\lim_{x\to 0}x^2 \sin\frac{1}{x}=0$. I am now stuck with the $\sin x$ under it, how does this affect the limit?

Find the limit: $$\lim_{x\to0}{\frac{x^2\cdot\sin\frac{1}{x}}{\sin x}}$$ After treating it with l'Hopital rule, we get: $$\lim_{x\to0}{\frac{2x\cdot\sin \frac{1}{x}-\cos\frac{1}{x}}{\cos x}}$$ Now, the numerator of fraction doesn't have a limit, so I can't use l'Hopital rule again. What to do? I can split it into two fractions, but I'm not sure how would it help: $$\lim_{x\to0}{\frac{2x\cdot\sin \frac{1}{x}}{\cos x}} - \lim_{x\to0}{\frac{\cos\frac{1}{x}}{\cos x}}$$


I have a coxme object: (Age, status) ~ F + X1 + X2 + (1|R1) + (1|R2) + (1|R3) Where F is an individual's level of inbreeding, X1 & X2 are covariate factors, and R1, R2 & R3 are random factors denoting non-independence between individuals, and breeding facility.   I understand that the coxme output gives me the % change in the rate of the event occurring due to inbreeding increase, but I'd like to get point estimates of survival to the 5th year of age for each inbreeding level from this model. With this, I'd like to calculate the effect of increasing inbreeding on survival to a specific point in time (giving us a rate which can be fed into population models for this species).   Seeing as there is no simple method to extract this data from acoxme object (e.g., survfit), is there a process by which I can extract it manually for specific points in time from my coxme fit?   Alternatively, would it be more appropriate to extract this data from Kaplan Meier curves for each inbreeding strata of the model without the random factors (I don't feel like it would be accurate, but I'm not 100% sure)?   My cox models may not be appropriate to use in determining this rate, but it's something that I've worked with a lot so far and I'd like to know if it is at all possible.   Any discussion, comments, advice would be greatly appreciated, Thanks.

I want to compute predicted survivor function for a Cox proportional hazards model with frailty terms [using survival package]. It appears that when frailty terms are in the model, the predicted survivor function cannot be computed.  ## Example  require(survival) data(rats)  ## Create fake weight set.seed(90989) rats$weight<-runif(nrow(rats),0.2,0.9)  ## Cox model with gamma frailty on litter fit <- coxph(Surv(time, status) ~ rx+weight+frailty(litter,dist="gamma"), data = rats)   ## Compute survival curve from the cox model for rx=0 and weight=0.5 kg plot(survfit(fit, newdata=data.frame(rx=0,weight=0.5)),xlab = "time", ylab="Survival")   ## Running this line, I get following error message: Error in survfit.coxph(fit, newdata = data.frame(rx = 0, weight = 0.5)) :  Newdata cannot be used when a model has sparse frailty terms   I tried using both sparse and non-sparse computation methods by using sparse=TRUE, Sparse =FALSE, sparse =0, sparse=5 options. However, none worked.  How do I compute predicted survivor curve based on my frailty model?


Firstly, I apologise if my thinking is completely incorrect - I am by no means a physicist (yet!), I have included layman illustrations to hopefully assist in explaining my thinking.  I am imagining the big bang to be, for lack of a better word, an explosion, thus the universe to be progressively expanding:    Therefore, to me it seems logical to suggest that there is an edge.  If this is the case, then is it reasonable to suggest that explosion + edge = 'bright edge'? Where light projects in all directions at the edge, not just outwards into the 'nothingness'.     So, this brings me to my question: why, when someone looks deeply enough 'at the edge' do they see an absence of light?   Again, apologies if I'm jumping to irrational conclusions & am way off.

By looking at this picture:    The earth is near the center of the universe. I've read that the universe look the same no matter where the observer is located. It is the same distance everywhere.  So I understand that for general relativity the universe need to be homogeneous and isotropic, so it will look the same no matter where I am.  But what if I'm on one of the planets near the right or left of the image, then if I draw the same picture of the universe, but from my perspective, then I would be also located in the center? If that's not the case (I'm actually near an edge), then part of my sky would be completely dark, and all the sky that way won't be isotropic?