I have previously flagged a comment and the flag has been declined. I am perfectly happy for the flag to have been declined but I would like to know which comment it is so that I can possibly learn from it.  Is it possible somewhere in my profile to view this? If not, should it be possible?

Note: This is not the same as , which is about the moderator tool. I am talking about the flag history page that is accessible through the user profile at .  I tend to have a pretty good hit rate for flags, well above 90% helpful on several sites. I also semi-regularly review the flag history page, both to see the status of any outstanding flags as well as see how flags I raised have been handled. Particularly, whenever a flag of mine is declined, I look over the post I raised the flag against with this new information in mind, to try to determine if I should change my flagging behavior in some way to better match the specific site's scope.  However, comment flags are difficult in this regard. Most often, there is only a binary status: helpful or declined. Helpful comment flags nearly always lead to the comment being deleted, so that obviously could present a bit of a problem, but that's not really relevant because a helpful flag means you should just keep doing what you've been doing. Declined comment flags, on the other hand, usually mean the comment is kept. It's the declined comment flags that I want to learn more about. But there's no way to!  All the flag says is which post it was on, how I flagged a comment, that I was the one to raise the flag (which frankly is rather useless information when you are already looking at your own flags summary), when the flag was raised and whether it's pending, helpful or declined. In a very few cases the moderator handling the flag may leave a helpful return comment.  This can get even more confusing if I raise multiple flags in quick succession against comments on the same question including any answers to it, because they basically all get bundled together.  Even in the case of a declined flag where the comment remains, there is no way to find your way back to the specific comment you flagged! Thus it is very difficult to recognize the error of your ways. Because comment flags (with few exceptions) are handled by diamond moderators only, the lack of feedback about which comment's flag was declined means it's easy to keep wasting the moderators' time without even intending to do so.  Hence my feature request: add a link to the specific comment that the specific flag was raised against, ideally only if that comment remains.


I run a multiple regression model having 2 independent variables. The R-squared value for my regression analysis on two predictor variables is 0.75. How do I interpret this value?

I'm really confused about the difference in meaning regarding the context of linear regression of the following terms:   F statistic R squared Residual standard error   I found  which gave me great insight in the different terms involved in linear regression, however the terms mentioned above look a like quite a lot (as far as I understand). I will cite what I read and what confused me:      Residual Standard Error is measure of the quality of a linear   regression fit.......The Residual Standard Error is the average amount that the response (dist) will deviate from the true regression line.   1. This is thus actually the average distance of the observed values from the lm line?     The R-squared statistic provides a measure of how well the   model is fitting the actual data.   2. Now I'm getting confused because if RSE tells us how far our observed points deviate from the regression line a low RSE is actually telling us "your model is fitting well based on the observed data points" --> thus how good our models fits, so what is the difference between R squared and RSE?      F-statistic is a good indicator of whether there is a relationship   between our predictor and the response variables.   3. Is it true that we can have a F value indicating a strong relationship that is NON LINEAR so that our RSE is high and our R squared is low


I have configured a svn server to access via http using apache2. However when I execute the  svn --version   in the terminal it gives me   svn, version 1.8.8 (r1568071)    compiled Sep 30 2014, 11:47:24 on x86_64-unknown-linux-gnu  Copyright (C) 2013 The Apache Software Foundation. This software consists of contributions made by many people; see the NOTICE file for more information. Subversion is open source software, see http://subversion.apache.org/   But when I access the repo in browser, it shows the version as follows.  Powered by Apache Subversion version 1.7.9 (r1462340).   How to determine the current svn server version correctly?

I want to know if my server is running Subversion 1.5.  How can I find that out?  Also would be nice to know my SVN client version number. svn help hasn't been helpful.  Note: I don't want my project's revision number, etc. This question is about the Subversion software itself.


I'm trying to calculate dates for monthly subscriptions. I've seen many  to use some variance of: const oneMonthFromNow = new Date(new Date().setMonth(new Date().getMonth()+1));  But when I test this for edge cases it doesn't work as expected, some examples:  Today: 31st march => Expected: 30th of April => Output: 1st of may (since 31 doesn't exist...?) Today: 30th January => Expected: 28th of February => Output: 2nd of March (what about leap years??)  Any ideas on how I can make this work without adding exception rules?

If you provide 0 as the dayValue in Date.setFullYear you get the last day of the previous month:  d = new Date(); d.setFullYear(2008, 11, 0); //  Sun Nov 30 2008   There is reference to this behaviour at . Is this a reliable cross-browser feature or should I look at alternative methods?


\documentclass{beamer} \usetheme{Copenhagen} \begin{document} \begin{frame}{Proton Pump Inhibitor use and the Risk of Chronic Kidney Disease } \framesubtitle{Benjamin Lazarus et al, in JAMA Intern Med. 2016;176(2)  } \begin{block}{Result}     \begin{description}         \item [Hazard ratio {\textit{unadjusted analysis}}:]1.45 95\% CI: (1.11-1.90)         \item [Hazard ratio \textit{adjusted} analysis for demographic, socioeconomic, and clinical variables:]1.5 95\% CI : (1.14-1.96)         \item [Hazard ratio for PPI verses H2RA:] 1.35 95\% CI : 1.01-1.91       \end{description} \end{block} \end{frame} \end{document}   Item 2 overflows through the block. I tried to use \\ to break it into two lines, but it ends up in error. Please help.

In my document I have a description environment. One of the titles in the description is too long to fit in one line and I want to break it. I know this is a bad styling but I can't think of any way to shorten it. I tried \\ and \newline and they didn't work. What else can I do?  I tried to use the mdwlist package. I added the following in the begining of my document:  \renewenvironment{description}{   \begin{basedescript}{%     \renewcommand{\makelabel}[1]{\bfseries##1}%   } }{%   \desclabelstyle{\multilinelabel}    \end{basedescript}%  }   but all I got is the same result.  I also tried this without any effect:  \renewenvironment{description}{   \desclabelstyle{\multilinelabel}   \begin{basedescript}{%     \renewcommand{\makelabel}[1]{\bfseries##1}%   } }{%   \end{basedescript}% }   I can't use the \multilinelabel since the words in the label are too long, thus, I want to use \pushlabel. However, this doesn't work even in the example you given (probably, it doesn't know how to break lines). Is there any way to force break lines?


For some reasons, the installation of Google talk failed and now I cannot install anything. First when I tried apt-get, I was asked to run this command:  sudo dpkg --configure -a   which went well, but still I get the following error when I try to install anything:  sudo apt-get install r-base Reading package lists... Done Building dependency tree        Reading state information... Done E: The package google-talkplugin needs to be reinstalled, but I can't find an archive for it.   If I try to reinstall google-talkplugin, Ubuntu Software Center cannot even start! how can I fix this bug?

Running Synaptic I get the following error message:  E: The package hl1440lpr needs to be reinstalled, but I can't find an archive for it. E: Internal error opening cache (1). Please report.   Upon accepting the message, Synaptic quits.


Is it possible disable and then erase all references in registry to unstoppable process to get rid of it for good?

I have recently installed a program that deploys an agent which "protects" from peripherals. What it actually does at this point is to block any kind of media I plug to my PC.  I've done some checking and I found the name of this service blocking my peripherals. So, naturally, I've tried stopping it.  First I tried the sc stop, but I was denied the access. Trying to do it by services.msc will result in not even giving me the priviledge to use stop on that service. Same response from taskkill: Access denied... Then I figured I'd try net stop resulting with the 2191 message which if I try net helpmsg 2191 does not give any information. I then decided to surf Superuser and found out about these pstools. But as soon as I try to do the cmd switch with psexec -s cmd I get the message:   Couldn't install PsExec service: access is denied.  Strangely, if I try to use just psexec it does prompt me with the help info. So this was a dead end again.  After all these fails I have decided to just remove it from startup right? So I open msconfig and remove the service from startup, save and finally reboot. Unfortunately, when PC reboots so does the service. By the time I can access the task manager the service is already running, again. Can't really imagine how though.  All these access failures made me think I might not have the required privileges or something, but my user account is set as administrator so I think there's nothing more I can do.


I was just checking the log table and then suddenly It came to my mind that how were log tables made before calculators/computers how did john Napier calculate so precisely the values of $\log(2),\log(5),\log(7)$ etc .   Is it even possible as I can't even estimate how much time it will take me to do this!! Did Napier use any sort of trick??

Henry Briggs compiled the first table of base-$10$ logarithms in 1617, with the help of John Napier.  My question is: how did he calculate these logarithms? How were logarithms calculated back then?  I've found   to be fairly useful, but they don't seem to say much in the way of what I'm looking for. Any answers or useful references would be appreciated.


I have 14,000 pictures sorted into files by year and month but taken with multiple cameras. I want the file name to reflect the date taken. All of my pictures are .jpg.   For example all pictures taken on October 16, 1998 are in a folder directory called   ..\1998\10 October\1998 10 16\   I want the all the pictures to be named 19981016_0001.jpg,  19981016_0002.jpg etc.   I can get to the point where it list the folder I want to change. But I'm unable to actually change it. I created a temp file of copies in case I messed it up. I started by typing   cd "C:\Documents and Settings\Brooke LastName\Desktop\Temp   then after successfully getting my file to load I used a formula I found on this site.  ls *jpg | Foreach {$i=1} {Rename-Item _ -NewName ("$($.19981016){0:00000000#} .jpg" -f $i++) -whatif}   The error I got said  Unexpected token ' .19981016' in expression or statement.   At line:1 char:12 + $.19981016 <<<<   I found several formulas on the web, but most created files that would number with parenthesis for example vacation (1).jpg. I want a four digit counter 0001 after an underscore at the end of my date.  Could someone help me out and give me dummy instructions? I have zero programming knowledge.

I have 14,000 picture sorted into files by year and month but taken with multiple cameras. I want the file name to reflect the date the photo was taken.   For example, all pictures taken on October 16, 1998 are in a folder called 1998\10 October\19981016.   I want the all the pictures to be named 19981016_0001 19981016_0002 etc.   I can get to the point where it list the folder I want to change but I'm unable to actually change it. All of my pictures are .jpg.  I created a temp file of copies in case I messed it up. I started by typing:  cd "C:\Documents and Settings\Brooke LastName\Desktop\Temp"    then after successfully getting my file to load I used a formula I found on this forum.  ls *jpg | Foreach {$i=1} {Rename-Item _ -NewName ("$($.19981016){0:00000000#} .jpg" -f $i++) -whatif}   The error I got said  Unexpected token ' .19981016' in expression or statement.  At line:1 char:12 + $.19981016 <<<<   The error repeated several times  I found several formulas on the web but most created files that would number with parenthesis for example vacation (1).jpg I want a four digit counter after an underscore at the end of my date. ie 19981016_0001


I was recently asked in an interview: How do you implement a Singleton design pattern in Java?  I was a little confused because there are 2 options:  1) Just have a static data member. A static member, e.g.   private static Logger logger;   will ensure that only one logger is shared among all objects of a given class.  2) Implement an instance-controller that restricts instances:  public class LoggerWrapper {         private static Logger instance = null;          private LoggerWrapper() {       }          public static Logger getInstance() {                 if (instance == null) {                         instance = new Logger ();                 }                 return instance;         } }   What is the difference between these 2 singleton approaches?

What is an efficient way to implement a singleton pattern in Java?


I try to use the commands cd.. and cd. in the terminal to move from my current folder to a previous one, and it shows me a message that the command doesn't exist...   What could the problem be? I'm using Ubuntu 18.04 LTS.

I am new to Linux and Ubuntu and have tried changing to folders/directories with some difficulty.  Could someone explain why the following commands failed to change to the desired target folder/directory?  sharon@sharon:~$ cd Home  bash: cd: Home: No such file or directory  sharon@sharon:~$ cd /Home  bash: cd: /Home: No such file or directory  sharon@sharon:~$ cd Documents  sharon@sharon:~/Documents$ cd Downloads  bash: cd: Downloads: No such file or directory  sharon@sharon:~/Documents$ cd /Downloads  bash: cd: /Downloads: No such file or directory  sharon@sharon:~/Documents$


I've recently downloaded and installed Ubuntu on my lenovo ideapad 100, and once in a while it seems it is connected to the wi-fi, but the browser doesn't load any page; but, after turning off and on the "Enable Wi-Fi" option, it usually reconnects. Right now, it won't connect again and won't show any available wi-fi around. Any way to get the internet back without restarting the whole system?

I have dual booted my Windows 8 laptop with Ubuntu 14.04. The wifi driver is Realtek rtl8723be. It didn't use to work but I updated the kernel to 3.18 and reinstalled the driver and that seemed to solve the problem for a few hours. Then it would be connected for around 30 minutes and then the connection would stop, even though the icon on the system tray would still indicate it's connected. The only thing that works is restarting the computer but then, again, after 30 minutes the connection stops.


If I charge my device and let it charge not fully but say, 60% and disconnect, does that hurt battery life? If so, what are the 'safe' ranges?

One of my friends has a relatively new Samsung smartphone. He has this app that notifies him whenever the charging is up to 80%, and tells him to unplug the charger.  He tells me that it will increase the number of charging cycles for his battery. He says that if he lets it charge all the way up to 100%, it will mean he has to replace the battery of the phone more often.  Is this true?  Somehow, I feel this is a thing of the past. I thought the internal architecture of batteries these days was made so that it wouldn't drop too low or too high. (In other words, when the phone is at 100%, it isn't really 100%. It's what the battery can safely be charged to in order not to degenerate too much.)  Here's a  which taught me something about this.


Program code :  int main()  {      int i;      for (i = 0; i < 0, 5; i++)          printf("%d ", i);      return 0;  }    The loop above is executed infinite times.  What does i<0,5 mean, and how it is evaluated?

How does the comma operator work in C++?  For instance, if I do:  a = b, c;     Does a end up equaling b or c?   (Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)  Update:  This question has exposed a nuance when using the comma operator.  Just to document this:  a = b, c;    // a is set to the value of b!  a = (b, c);  // a is set to the value of c!   This question was actually inspired by a typo in code.  What was intended to be  a = b; c = d;   Turned into  a = b,    //  <-  Note comma typo! c = d;


I am trying to create a DatePicker dialog that opens when a button in my dialog made from a custom layout is pressed. I have tried many different configurations of code and the result when the button is pressed is always either a NullPointerException or the button does nothing. I am pretty new to android programming but my best guess is that findViewById is not able to find the button because I am working in a Fragment and the content view is not specified. I tried to use setContentView but that wasn't working. Hopefully someone can figure this out and let me know how they did it!  NewTaskDialogFragment.java:  public class NewTaskDialogFragment extends DialogFragment implements         android.view.View.OnClickListener {     public int mYear, mMonth, mDay;     public static final int DIALOG_ID = 0;     private Button btn;     private View dialogView;       public Dialog onCreateDialog(Bundle savedInstanceState) {         Context context = getActivity();           AlertDialog.Builder builder = new AlertDialog.Builder(context);           LayoutInflater inflater = LayoutInflater.from(context);          dialogView= inflater.inflate(R.layout.new_task_dialog, null);         builder.setView(dialogView)          ;         btn =(Button) dialogView.findViewById(R.id.datePickerDialogButton);         showDialogOnButtonClick();          return builder.create();     }     public void showDialogOnButtonClick(){            btn.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 getActivity().showDialog(DIALOG_ID);             }         });     }      private DatePickerDialog.OnDateSetListener dpickerListener             = new DatePickerDialog.OnDateSetListener() {         @Override         public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {             TextView dateDisplay = (TextView) getActivity().findViewById(R.id.dateDisplayBox);              mYear = year;             mMonth = monthOfYear;             mDay = dayOfMonth;             dateDisplay.setText(mYear + mMonth + mDay);         }     };      @Override     protected Dialog onCreateDialog(int id){         if(id == DIALOG_ID) {             return new DatePickerDialog(getActivity(), dpickerListener , mYear, mMonth, mDay);         }else{             return null;         }     }       @Override     public void onClick(View view) {      } }

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?


If I were buying my first "serious" camera, is there any value in buying a "full beginner's kit" like the below or should I just buy the camera with the kit lens? The full kit costs about $100 (or 10%) more than the camera and kit lens.  Overview of kit [brand names, other than Canon, obscured]

Let me start by saying I'm a newbie to photography and appreciate all help! I purchased a camera "package" on Amazon.  This 33rd Street Deluxe Bundle Includes : Canon EOS Rebel T5i DSLR Camera with Canon EF-S 18-55mm f/3.5-5.6 IS STM Lens.   2.2x HD AF Telephoto Lens 0.43x HD AF Wide Angle Lens   There were other standard items included but I'm concerned about these two add-on lenses. I can't figure out how to attach them. My book says EF lenses and these are AF lenses. Did I purchase lenses that won't work on my camera? I really need to know quick so I can return the package if they can't be used. Again, any and all help is greatly appreciated!


I need a regex that will match the following line:  {"httpStatus": "OK", "payload": {"status": "OK"}, "httpCode": 200}   but not  {"httpStatus": "OK", "payload": {"status": "OK", "config": {}}, "httpCode": 200}   So basically it should match the string if it not contains config  For checking if the string contains status the regex is:  (?=\"status\": \"OK\")

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


Error message: “The app submitted an invalid request. Please let us know on Meta.” As requested, I am letting you all know here on Meta. Steps to reproduce:  Install iOS app Tap “Sign Up” Tap “Sign up using Stack Exchange”

I'm using the official Stack Exchange mobile app for iOS or Android, and  My app crashed! It doesn't look good on my new smartphone. It won't run after I updated my device. I noticed another bug. I have an idea for a new feature which is currently not in the app.  How do I report bugs with or request features for the iOS and Android apps? Also:  I've used the built-in functionality of the app to report a bug or submit a feature request. Did I do the right thing? The app prompted me to post on Meta after an error occurred. Should I post about it here? I'm wondering why the latest version is from 2017. I've heard rumors that the apps are no longer supported; is that true? I can't find the app on my device's app store anymore! Where did it go?     We get a lot of bug reports from users about the mobile apps, which are unsupported, and at the moment, there is no centralized Q&A pair for those to be closed as duplicates of (the relevant answers are spread across multiple unrelated questions). This question is an FAQ proposal, to serve as a directly-related duplicate target for those questions.


I have given seven cipher text encryted by the many-time pad. All are encrypted uwith the same random chosen secret key but I have no idea how to decrypt them. There are 7 ciphertexts: 758c7313325a32e070d50a8fc9993a7822f54e88c7433f3ef29da27405eb1a 688a705c265e21f17fd51c8fd6933e6270f549d1860a3e7bffd0a27a19fb1af947 7196795426522de87fd4158fd69e32626ef81dc6c9176d39f39db67c0de912f446fe31 758c73133c5a33f179c81bcecb857d6476e959d1860b2428e2d2a06c 718c6f403d5033a57fc952d8cd97293772f444dbcf002428e2cef2661ffa1fee 758c7313245b39f67fd91bcecb857d6770fd5edccf00287bfbd8b67c08e615f2 758c7f40744332ea74d617c2859f2e376cf34988d20b2c2fb6d9bb730de618e25fe6

Suppose Alice wants to send encryptions (under a one-time pad) of $m_1$ and $m_2$ to Bob over a public channel.  Alice and Bob have a shared key $k$; however, both messages are the same length as the key $k$.  Since Alice is extraordinary lazy (and doesn't know about stream ciphers), she decides to just reuse the key.  Alice sends ciphertexts $c_1 = m_1 \oplus k$ and $c_2 = m_2 \oplus k$ to Bob through a public channel.  Unfortunately, Eve intercepts both of these ciphertexts and calculates $c_1 \oplus c_2 = m_1 \oplus m_2$.     What can Eve do with $m_1 \oplus m_2$?     Intuitively, it makes sense that Alice and Bob would not want $m_1 \oplus m_2$ to fall into Eve's hands, but how exactly should Eve continue with her attack?


In Lubuntu 16.04 I have installed network-manager-pptp.  I then   click the network manager icon click "VPN Connections" click "Configure VPN" click "Add"   But the "Choose a Connection Type" dropdown includes groups of Hardware and Virtual options, but no VPN options.  Can anyone suggest why?  On my Lubuntu 14.04 system the VPN options do appear as expected...

There is no PPTP VPN in network manager connection type dialogue.  Packages pptp-linux network-manager-pptp are installed.


I learned in  and in  that electrons repel from each other by exchanging photons. This makes sense when it comes to electrons, but what happens when two protons or two positrons repel each other? Do positively charged particles also exchange photons?

Since Newton's law of gravitation can be gotten out of Einstein's field equatons as an approximation, I was wondering whether the same applies for the electromagnetic force being the exchange of photons. Is there an equation governing the force from the exchange of photons? Are there any links which would show how the Coulomb force comes out of the equations for photon exchange? I know that my question is somewhat similar to the one posted here , but it doesn't really have an answer to my question specifically.


What does the TRUNCATE do differently to drop?   I believe it deletes all the data in the table but keeps the table name in the database, where as DROP deletes all data and the table. Is this correct ?

I am trying to get a greater understanding on the differences between the DELETE and TRUNCATE commands. My understanding of the internals goes something along the lines of:  DELETE -> the database engine finds and removes the row from the relevant data pages and all index pages where the row is entered. Thus, the more indexes the longer the delete takes.  TRUNCATE -> simply removes all the table's data pages en mass making this a more efficient option for deleting the contents of a table.  Assuming the above is correct (please correct me if not):   How do different recovery modes affect each statement? If there is any effect at all When deleting, are all indexes scanned or only those where the row is? I would assume all indexes are scanned (and not seeked?) How are the commands replicated? Is the SQL command sent and processed on each subscriber? Or is MSSQL a bit more intelligent than that?


I am trying to download videos from "web of stories" (). I tried all suggestions on , but no one worked. My browser is Firefox 11.0. Any ideas?

I have read  but please hear me out.  I use Ubuntu 10.04 LTS (32-bit) and I didn't bother to install the Flash plugin for Firefox as I am using a netbook and sometimes Flash caused firefox to crash. What I would like to ask is if I had the link to the video, is there some way I can download it and watch it offline (via VLC) so that I don't need to install Flash plugin? Command line or GUI techniques is welcome.  Based on what I have read, using the /tmp technique requires Flash plugin to be installed and the video to be loaded before I can go scavenge it in the said directory. Note that I also want to dload videos from site aside from youtube.


We define potential as work done by ext. agent in moving charge from infinity to point of observation. Then how do we often take Earth to be at zero potential?  And if we can arbitrarily choose to call a reference point, how would my measurements change if I took Earth at 100 V?

For a localized charge distribution the potential is set to zero far away from the charge distribution (at infinity)  Now, when grounding a conductor, i.e. connecting it to Earth, it is said that we are setting its potential to zero.   Why Earth's potential is zero? And if it is zero, is it zero even if the potential is still zero at infinity?


Let $f$ be in $L_1(\Bbb R^N)$ and $g$ be in $L_q(\Bbb R^N)$ for $q \in (1, \infty)$. Show that $(f*g)(x)= \int_{\Bbb R^N}f(x-y)g(y)dy$ is in $L_q(\Bbb R^N)$ and that $||(f*g)(x) ||_q \le ||f||_1||g||_q$    I had trouble getting past the following part.  $||(f*g)(x) ||_q^q= \int_{\Bbb R^N} \big  |\int_{\Bbb R^N}f(x-y)g(y)dy \big|^q dx  \le \int_{\Bbb R^N} \left(\int_{\Bbb R^N}|f(x-y)||g(y)|dy \right)^q dx $  Any help is appreciated

Let $1\le p < \infty$. Let $g \in L^p(\Bbb R^n)$, and $f \in L^1(\Bbb R^n)$.   Show: $||f*g||_p \le ||f||_1||g||_p$, where $*$ indicates the convolution defined by   $$ f*g (x) := \int f(x-t) g(t)dt.$$  Here is a relevant hint, apparently:  Let $q$ be the conjugate of $p$. Note that:  $$|f*g| \le \int [|g(t)||f(x-t)|^{1/p}]|f(x-t)|^{1/q}dt,$$ then apply Holder's inequality.  I did exactly as the hint suggested, and ended up with what looked like a meaningless inequality compared to the final answer. I even took the $p$ power of both sides.   Any help?


I have heard again and again that using the digital viewfinder on your SLR is a big no-no and that you should always use the optical viewfinder when framing a shot.  Why?

Forgive this novice question, I am basically a complete newbie to photography.  Really, all I've ever used for most my of short life have been point-and-shoots; I've only recently started to pick up some curiosity.  Anyway, from what I've gathered, reading through many of the  questions, most serious photographers use the optical viewfinder as their primary tool to determine what makes a good shot.  Live-preview isn't used much at all; it seems its help is to primarily set up the shot.  Reading a Wikipedia article seems to confirm this view, adding that      [l]ive preview in DSLRs does not typically serve as their principal means of framing and previewing before taking a photograph, with this function still being mainly performed with optical viewfinder. While initially largely a novelty feature, live-preview functionality has become more common on DSLR cameras...    My questions are:   What are the myriad advantages of using the viewfinder over live preview, what does it help one accomplish in achieving the goals of photography? What are some interesting ways serious photographers use live preview to take better shots they might have otherwise missed?


I have a File called Customer_Info.csv which has sample data like :  CUST_ID FIRST_NAME  LAST_NAME   USER_TYPE   REPORTS_TO_ID   EMAIL   FIRST_TIME_LOGGED_IN    FIRST_TIME_LOGIN_DATE   ADDRESS_LINE1   ADDRESS_LINE2   CITY    STATE   ZIP  10001   MICHELLE    VILLEGAS3   Savings SRINATH MICHELLE.VILLEGAS3@NOBODY.COM   Y   07-10-18    1050 WEST FIFTH STREET      AZUSA   IND 917023308  This is the table in which i need to store the data. I am storing everything in string format because it is just a staging table.  Create Table Customer_Info_ST  (  Cust_ID varchar(5),  First_Name varchar(15),  Last_Name varchar(15),  User_Type varchar(10),  Report_To_Id varchar(10),  Email varchar(30),  First_Time_Logged_In varchar(1),  First_Time_Login_Date varchar(11),  Address_Line1 varchar(30),  Address_Line2 varchar(30),  City varchar(15),  State varchar(3),  Zip varchar(12)  );   I have written the following code to store it in the table.  public class CustInfoDataLoader {  static String sql, tableName; private static PreparedStatement pstmt; private static Statement stmt; private static final String filePath = "Customer_Info.csv";  public static void main(String[] args) throws SQLException, FileNotFoundException, IOException, ParseException {      readCsv("Customer_info_ST"); //Line 24 in my code      //readCsvUsingLoad(); }  private static void readCsv(String tableName) throws FileNotFoundException, IOException, SQLException, ParseException {     CSVReader csvreader = null;      try{         Reader reader = Files.newBufferedReader(Paths.get(filePath));         csvreader = new CSVReaderBuilder(reader).withSkipLines(1).build();         sql = "insert into ? values (?,?,?,?,?,?,?,?,?,?,?,?,?)";         ManageDBResource.createConnectionToDB();         pstmt = ManageDBResource.conn.prepareStatement(sql);           String[] rowData = null;          while((rowData = csvreader.readNext()) != null) {              pstmt.setString(1, tableName);             int i = 2;             String state = rowData[11];             for (String data : rowData) {                  if(i == 9 && data != null && state != "IND") {                     java.text.SimpleDateFormat source = new java.text.SimpleDateFormat("MM-dd-yyyy");                     java.util.Date date = source.parse(data);                     java.text.SimpleDateFormat target = new java.text.SimpleDateFormat("yyyy-MM-dd");                     data = target.format(date).toString();                 }                 pstmt.setString(i++,data);                 //System.out.print(data + " ");             }             int result = pstmt.executeUpdate();             //System.out.println();             if(result == 1) {                 System.out.println("Data loaded Successfully.");              }         }     }     catch (Exception e) {         System.out.println(e.getMessage());     }     finally {         pstmt.close();   //Line 69 in my code file         csvreader.close();     }  }   and I get the following error:  Exception in thread "main" java.lang.NullPointerException at CustInfoDataLoader.readCsv(CustInfoDataLoader.java:69) at CustInfoDataLoader.main(CustInfoDataLoader.java:24)

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?


Adding energy to water makes it's temperature increase. This continues until it reaches 100 °C (at 1 atm) when it turns to vapor with a vaporization energy of 2257 kJ/kg. But if we lower the pressure on the water, it can start boiling at lower temperatures. In this case, would it's vaporization latent heat still be 2257 kJ/kg?   If not, how does the latent heat of water depends on boiling temperature or vapor pressure?

What is latent heat of vaporization ($L_v$) in the first place?  seems to indicate that it is the energy used in overcoming intermolecular interactions, without taking into account at all any work done to push back the atmosphere to allow for an increase in volume when a liquid boils.  If that is so, then would it be correct that $L_v$ decreases as boiling point rises, because at the higher boiling point, less energy is required to overcome the weaker intermolecular interactions?  Otherwise, would it then be correct to say that $L_v$ increases as boiling point rises, assuming constant-volume?  Let's say there is a beaker containing 1 kg of liquid water at the boiling point, and an identical beaker, containing an identical amount of water at the same temperature. However, this second beaker is perfectly sealed such that the volume of its contents, both liquid and gaseous, will not change.  Since both liquids are at the boiling point, applying heat should cause boiling to occur. Compared to the first beaker, then, would the second beaker (in theory) require more or less heat for its 1 kg of liquid water to completely boil?  Thanks!


If $0 < r < 1$ show that $r^n$ goes to $0$ as $n \to  ∞$.  If $|r| < 1$ then  $r^2  < r$  similarly $r^4 < r^3 < r^2 < r$  so $r^n$ as $n \to +\infty$ will be equal to $∞$  Let $r=\frac1m , m>1 \to$ you need to show $$lim_{n\to +\infty} r^n = ∞$$ Since $0<r<1$ $$lim_{n\to +\infty} r^n = lim_{n\to +\infty} \left(\frac1m\right)^n=lim_{n\to +\infty}\frac{1}{m^n} = \frac{1}{+\infty} = ∞$$

If $0 < r < 1$ show that $r^n$ goes to $0$ as $n \to 1$.  If $|r| < 1$ then  $r^2  < r$  similarly $r^4 < r^3 < r^2 < r$  so $r^n$ as $n \to +\infty$ will be equal to $1$  how can i finish this problem?


I've recently started working with Blender and i CONSTANTLY get this issue when i make 2 meshes and join them together to form 1 mesh.   This is what it looks like before i join the 2 meshes:   An this is what i get when i join them. (The magazine is not yet joined with the other meshes) Any help on this issue will be really appreciated. Thanks for the attention!

While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered.   The blackening effect is visible in the viewport too.  How can I solve this problem?


I'm trying to generate a stream of tuples $(a, b, c)$ that satisfy the equation  $2a^2 + b^2 = c^2$  The first $10$ results are:  $2,   1,  3$  $4,   2,  6$  $6,   3,  9$  $4,   7,  9$  $6,   7,  11$  $8,   4,  12$  $10,  5,  15$  $12, 1,  17$  $12, 6, 18$  $8, 14, 18$  There is a solution for $x_2+2y_2=z_2$ which is exactly the same but I cannot understand how I can produce all these numbers as a function. For instance, it says $x_3=(a_2+2b_2)t=3$ which is the solution of $c$, in my case, but it includes $x_3$ because $t = \dfrac{1}{2}(x_1+x_3)$. In addition, he gives the values $\{x_1,x_2,x_3\} = \{1,2,3\}$ but I'm not sure which are the next values. Any help please. Thank you in advance!!!

I'm use to finding the solutions of linear Diophantine equations, but what are you suppose to do when you have quadratic terms? For example consider the following problem:  Find all solutions in positive integers to the following Diophantine equation $x^2 + 2y^2 = z^2$  I'd usually start by finding the gcd and use some other tricks, but I'm not sure how to approach this type of problem


The impact panel seemed off/different to me lately, and that's because, well, it is.    There's a new Impact panel* and I feel it can use some adjustments.       OLD            NEW    There's all of this extra empty whitespace which looks very odd.  I think we should add back in the horizontal rule and provide a bit more spacing between the edits, flags and votes. (Like the way it was before)  I'm guessing that it's related to the .  *This change was implemented across all sites

It seems that the Impact space has gotten larger and the Badges space narrower. In my opinion, this looks rather uncomfortable to me as there is that really unnecessary gray space.     Also, the X-axis of the reputation graph is broken:    Can this please be fixed?


Question: In which part of a accelerating spacecraft does time pass more slowly?  Therefore does time pass more quickly or slowly at high altitudes in a gravitational field.

The picture shows an accelerating spaceship with two clocks inside it. It is so far away from all other bodys that gravity is of no importance.   Will the bottommost clock be slower than the topmost one? Or will both clocks have the same speed?


It seems as if there is no difference whatsoever. When the whoami or id commands are run, they all yield root credentials. Is this an illusion? If the root account is disabled by default in Ubuntu, and therefore su gives and authentication error, then why allow sudo -I  Edit: Excuse me, the ONLY difference I have learned of is that sudo -I asks for the password of the user who invoked the command, and su asks for root, or some other target user's password.  Is there any OTHER difference?

I already read it from manual but I can't see difference..  su - change user ID or become superuser  sudo -s [command]   The -s (shell) option runs the shell specified by the SHELL environment variable if it is set or the shell as specified in passwd(5).  If a                    command is specified, it is passed to the shell for execution.  Otherwise, an interactive shell is executed.  sudo -i disappear description in manual


I installed Ubuntu 12.04 over a Toshiba P50-A-12z and after reformattting the disk with windows8 (I always kept windows before on a smaller partition but this time, windows8 was to bad even for me to keep so there it goes).   After doing a recommended upgrade of Ubuntu I solved some issues but I still am having problems with the wireless (I get a good wired connection though). Wireless used to work well with Windows8 before removing it from my system. I had to play with the BIOS to install Ubuntu from disk (disable the UEFI) but I doubt this should have any effect on the wireless performance. I tried many things I saw in this and other forums but nothing seems to work. I suspect the issue is on the driver that may not be available as on Intel's website say this device was released on the second half of 2013 and maybe too new for unsoported OS?. I checked on intel's webpage and even though they say the offer support for linux could not find the driver for what I think is my wireless device. Still, I hope a smart shoul from this forum could offer some help.  Any help would be much appreciated. First, some useful info.   rfkill only shows bluetooth. Pressing F12 turns bluetooth on and off but no sign of wireless  rfkill list 5: hci0: Bluetooth Soft blocked: no Hard blocked: no   lshw -C network shows the device is UNCLAIMED.    *-network UNCLAIMED         description: Network controller    product: Wireless 7260    vendor: Intel Corporation    physical id: 0    bus info: pci@0000:03:00.0    version: 73    width: 64 bits    clock: 33MHz    capabilities: bus_master cap_list    configuration: latency=0    resources: memory:f7900000-f7901fff   *-network    description: Ethernet interface    product: QCA8171 Gigabit Ethernet    vendor: Qualcomm Atheros    physical id: 0    bus info: pci@0000:04:00.0    logical name: eth0    version: 10    serial: 54:be:f7:73:00:bd    size: 100Mbit/s    capacity: 1Gbit/s    width: 64 bits    clock: 33MHz    capabilities: bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=alx driverversion=1.2.3 duplex=full firmware=N/A ip=192.168.1.105 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s    resources: irq:19 memory:f7800000-f783ffff ioport:d000(size=128)   lspci shows what I think is the best description of the hardware. I should have checked this info from windows8 but now is too late. Is there other way of finding out if this is the hardware or can I trust the info from lspci?  lspci 03:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73) 04:00.0 Ethernet controller: Qualcomm Atheros QCA8171 Gigabit Ethernet (rev 10)   From my limited knowledge, I think the driver is alx (is it?). Below some info about it:  modinfo alx filename:       /lib/modules/3.8.0-34-generic/kernel/ubuntu/alx/alx.ko version:        1.2.3 license:        Dual BSD/GPL description:    Qualcomm Atheros Gigabit Ethernet Driver author:         Qualcomm Corporation, <nic-devel@qualcomm.com> srcversion:     896F432F7919E2B2C08B0B3 alias:          pci:v00001969d000010A0sv*sd*bc*sc*i* alias:          pci:v00001969d000010A1sv*sd*bc*sc*i* alias:          pci:v00001969d00001090sv*sd*bc*sc*i* alias:          pci:v00001969d00001091sv*sd*bc*sc*i* depends:        mdio intree:         Y vermagic:       3.8.0-34-generic SMP mod_unload modversions    Do I need to upgrade this driver or wait for a newer version?  Thanks!

I have a Dell XPS 12 running Ubuntu 13.10 and it doesn't appear to find it's wireless.  I have tried the suggestions  but they made no difference  peter@xps:/lib/firmware$ ls -l /lib/firmware/iwlwifi-7260-7.ucode  -rw-r--r-- 1 root root 682892 Aug  4 12:50 /lib/firmware/iwlwifi-7260-7.ucode peter@xps:/lib/firmware$ sudo lshw -c network   *-network UNCLAIMED             description: Network controller        product: Wireless 7260        vendor: Intel Corporation        physical id: 0        bus info: pci@0000:06:00.0        version: 63        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress cap_list        configuration: latency=0        resources: memory:f7c00000-f7c01fff  peter@xps:~/backports-3.10-2$ grep IWL7260_UCODE_API_MAX drivers/net/wireless/iwlwifi/iwl-7000.c  #define IWL7260_UCODE_API_MAX   7     .ucode_api_max = IWL7260_UCODE_API_MAX,         \ peter@xps:~/backports-3.10-2$ dmesg | grep iwl peter@xps:~/backports-3.10-2$ iwconfig lo        no wireless extensions.  peter@xps:~$ find / -name *7260-6* peter@xps:~$ find / -name *7260-7* /lib/firmware/iwlwifi-7260-7.ucode   peter@xps:~$ dmesg | grep -i -A 20 intel [ 1318.013278] Intel(R) Wireless WiFi driver for Linux, in-tree:d [ 1318.013281] Copyright(c) 2003-2013 Intel Corporation [ 1318.015154] cfg80211: World regulatory domain updated: [ 1318.015157] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) [ 1318.015159] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015161] cfg80211:   (2457000 KHz - 2482000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015162] cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) [ 1318.015164] cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) [ 1318.015165] cfg80211:   (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)     What I have found is that it appears to be loading an old version of the firmware but I don't know how or why  peter@xps:/lib/firmware$ modinfo iwlwifi | grep 7260 firmware:       iwlwifi-7260-6.ucode peter@xps:/lib/firmware$ ls *7260-6* ls: cannot access *7260-6*: No such file or directory   Any suggestions of how to get this setup very welcome.


This is a topic which thoroughly confuses me, I've read in my textbook that:      Absolute zero is the lowest temperature possible. At this temperature,   the internal energy is a minimum. The kinetic energy of all molecules   is zero.   So far this makes logical sense to me, however, the textbook goes on to say:     The internal energy is not zero because the substance still has   electrostatic potential energy stored between the particles.   For me, this is the confusing part because electrostatic potential energy is negative. So surely at absolute zero, the internal energy would be negative. I then asked myself whether the internal energy is always negative and came to the conclusion that that cannot be the case. For instance, a gas would (I think) have positive internal energy, due to negligible potential energy and kinetic energy would be positive.  I've looked around and unfortunately, I can only seem to find articles about the change of internal energy being zero. Admittedly, for the course I'm studying this is as in depth as it gets regarding thermodynamics, so I don't really have any knowledge of entropy / other things related to thermodynamics.

I got to read Volume I of Feynmann's lectures. It said that at absolute zero, molecular motion doesn't cease at all, because if that happens, we will be able to make precise determination of position and momentum of the atom. We do know that Heisenberg uncertainty principle holds for microscopic particles in motion. But what then is wrong to consider that all molecular motion ceases at absolute zero? In other words, does the uncertainty principle not hold when there is no motion?  Need some help!


imagine we have a country that has 15 cities . every city is connected to at least 7 other cities by directed road. how to prove that from every city in this country we can go  to every  another cities in this country ? actually i tried to draw a graph for that but i could not reach to a strong formula or proof that is suitable for this problem please help me solve it in every way you think is true.

I was wondering if someone can help me understand how prove that this graph is connected.  Given a graph with n vertices, prove that if the degree of each vertex is at least $(n − 1)/2$ then the graph is connected.  So far I know that about connected graphs:  An undirected graph is called connected if there is a path between every pair of distinct vertices of the graph  The distance between two vertices in a graph is the length of the shortest path between them.  The diameter of a graph is the distance between the two vertices that are farthest apart.


When I use \parencite for example, it creates a hyperlink in the PDF which I can click to get to the reference in the bibliography. However, with \citeauthor and \citeyear it does not create one. It does create a mention in the bibliography however, so that is not the problem.  Does anybody know how to fix this? I don't know all the relevant commands for this, I use a standard template found on Overleaf. But the command for my bibliography is the following:  \usepackage[backend=bibtex,style=authoryear,maxcitenames=2,maxbibnames=15,natbib=true]{biblatex}   And the following I found in the .cls file:  \ifbool{hyperrefsupport}{% If the nohyperref class option has not been specified \AfterPackage{biblatex}{ % Load the hyperref package after the biblatex package for compatibility  \RequirePackage{hyperref} % Required for customising links and the PDF \hypersetup{pdfpagemode={UseOutlines}, bookmarksopen=true, bookmarksopenlevel=0, hypertexnames=false, colorlinks=true, % Set to false to disable coloring links citecolor=Crimson, % The color of citations linkcolor=red, % The color of references to document elements (sections, figures, etc) urlcolor=magenta, % The color of hyperlinks (URLs) pdfstartview={FitV}, unicode, breaklinks=true, }\   Thanks in advance!  Edit: I found how to do it for the \citeauthor command by adding the following to the preamble: However, I was unable to modify it to work for \citeyear.  \DeclareCiteCommand{\citeauthor}%   {\boolfalse{citetracker}%    \boolfalse{pagetracker}%    \usebibmacro{prenote}}   {\ifciteindex      {\indexnames{labelname}}      {}%    \printtext[bibhyperref]{\printnames{labelname}}}   {\multicitedelim}   {\usebibmacro{postnote}}

When used in concert with the hyperref package, biblatex automatically creates hyperrefs for citations but not if they are inserted using \citeyear or \citeyearpar. Is it possible to add a hyperref to year only citations?  \documentclass{article}  \usepackage[backend=biber,natbib=true, style=authoryear-comp]{biblatex}  \usepackage{filecontents}  \begin{filecontents}{\jobname.bib} @article{ref1,   author = {Doe, John D.},   title = {Hyperrefs to citations},   journaltitle = {Links Everywhere},   volume = {1},   date = {2000},   pages = {1--2}, }  \end{filecontents}  \addbibresource{\jobname.bib}  \usepackage{hyperref}  \begin{document}  citet -- \citet{ref1}  citeyear -- \citeyear{ref1}  citeyearpar -- \citeyearpar{ref1}  \printbibliography  \end{document}


When do we need to use a structure in a pure C++ program? Is structure at all required in a pure C++ program?  I understand that structure is the only way in a C program to encapsulate members and function pointers.  But, if I use C++ to code my complete module, is it 100% alright if I stay away from structures and use a Class instead? Am I missing something?  (I googled but my question is very specific - is structure useless in pure C++ code)  === EDITED === My question is not about the difference or commonalities between a structure and a class, but, do we need "struct" at all in C++, when you can 100% do away with a class.  Is structure not redundant construct in C++, except for backward compatibility with C?    I understand the difference between them w.r.t. the access specifiers but there are only syntactic differences.

In what scenarios is it better to use a struct vs a class in C++?


For people on medication in which alcohol is strictly prohibited, is there a substitute that one can use in recipes that call for white wine?

If someone cannot or will not use wine for cooking, what would be a good substitute?   Question applies to both red and white wine.


What kind energy of electrons is lost when current passes through a resistor?  OR   What happens to electrons when they pass through a resistor? Does current decrease when its passes through a resistor? Does voltage also decrease???

I will give this question a little context. Firstly, as I understand it, as soon as I "close the switch" on a circuit, electric current pretty quickly establishes a steady state where, at any given cross section along a wire, the average kinetic energy of that slice is both constant and equal anywhere along the wire. (Please correct me if I am misunderstanding).   If the average kinetic energy is constant anywhere throughout the wire in the circuit (which confuses me, as I would think that the electrons should all accelerate after exiting the resistor since they are no longer being impeded as much), that means that the average velocity is constant. So, in the example of a simple circuit with a battery of v Volts and a resistor of o Ohms, my question is the following:  Because a 'voltage drop' is known to occur across the resistor, what type energy is being "traded" to generate the heat that radiates from the resistor? I would think that the reflexive answer is "electrical energy"...hence the VOLTAGE drop (the sacrificed energy is clearly not kinetic, as the velocity is constant everywhere). However, I find this confusing. Does this mean that if I had a positive test charge, it would be easier for me to bring it to the beginning of the resistor as compared to bringing it to the end of the resister?     Further, if the correct answer IS "electrical energy", why exactly DOES electrical energy get "dissipated" as the electrons pass through the resistor? I always here the comment Oh! It's because all the electrons are running into densely packed crap which impedes their flow but that to me sounds like a reason for their KINETIC energy to be reduced. However, clearly that's not the case. So, ultimately, I guess the real question is:  **What goes on in the resistor that is literally removing electrical energy **. I am sure that this is a quantum mechanics question, but my quantum mechanics knowledge is not terribly strong. If I could get an answer that is devoid of crazy wave function equations, I would greatly appreciate it. Thanks!


is there a change for HTML-Mouseover (I dont know the exact wording in english-version. German: Anzeigen, Kartenhinweis) between Version 2 and 3? The same code dont work in V3 ;(
  [%"field_2"%]      field_1 and field_2 is Path an filename:

How do you display a photo map tip in QGIS 3 on Windows?  As a new user I'm not sure if this is my lack of experience or a bug, so I've tried to simplify it as far as I can:  This is the contents of the Layer Display properties.

test

   and this is how it appears:    C:\Local\aa.jpg is real file I'm using to try to figure out what the problem is. What am I doing wrong?


I have a test table with following structure.  CREATE TABLE [dbo].[DW_test]( [ID] [bigint] IDENTITY(1,1) NOT NULL, [CourtCaseID] [int] NOT NULL, [ActionID] [int] NOT NULL, PRIMARY KEY CLUSTERED([ID] ASC)   Next I populated my table with about 470 million records with the following script.  insert into DW_test --select count(*) --from ( select top 1000000 abs(checksum(newid())) % 100000 + 1 a, abs(checksum(newid())) % 10 + 1 b from sys.all_objects cross join sys.all_objects a cross join sys.all_objects b cross join sys.all_objects c cross join sys.all_objects d cross join sys.all_objects e cross join sys.all_objects f cross join sys.all_objects g --) t GO   The script was executed about 470 times to generate 470 million records in the table and created NCCI on that table.  CREATE NONCLUSTERED COLUMNSTORE INDEX [IX_test1] ON [dbo].[DW_test] (     [CourtCaseID],     [ActionID] )   Next I test simple query to count the records in the table.  DBCC DROPCLEANBUFFERS GO select COUNT_BIG(*) from DW_test    If I turn SET STATISTICS IO ON I get the following results  With cold cache     Table 'DW_test'. Scan count 25, logical reads 3, physical reads 0, read-ahead reads 0, lob logical reads 469697, lob physical reads 1, lob read-ahead reads 1877324.      Table 'DW_test'. Segment reads 453, segment skipped 0.      Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.   With warm cache     Table 'DW_test'. Scan count 25, logical reads 3, physical reads 0, read-ahead reads 0, lob logical reads 229248, lob physical reads 0, lob read-ahead reads 0.      Table 'DW_test'. Segment reads 453, segment skipped 0.      Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.`   I know that 1 logical read is a single data page read from buffer pool during query execution and 1 physical read is a single data page read from disk.  that read-ahead read is:      This number tells us how many of the physical reads were satisfied by SQL Servers ‘Read-ahead’ mechanism.  This is directly tied to physical reads, so if there are no physical reads, you will have 0 for Read-Ahead reads.    In my case I am dealing with lob logical, physical and read ahead reads. I want to understand what this number means in my particular case.   How it is possible to have only 1 lob physical read with cold cache if the table has about 470 million records?  How it is possible the total number of lob pages decreased from about 2.3 million in cold cache to about 220k in warm cache?

After creating tpch database in my SQL Server, I tried below query:      set statistics io on     DBCC DROPCLEANBUFFERS;             select top 100 * from dbo.lineitem order by l_partkey;   The table lineitem has a non-clustered index on l_partkey. I issued the above queries for several times and found out that the logical reads vary each time:      Table 'lineitem'. Scan count 1, logical reads 1019, physical reads 4, read-ahead reads 1760, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.     Table 'lineitem'. Scan count 1, logical reads 1007, physical reads 4, read-ahead reads 1720, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.     Table 'lineitem'. Scan count 1, logical reads 1030, physical reads 4, read-ahead reads 1792, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.   From the post here: , I know it could be caused by read ahead behavior.  BUT exactly why read ahead could cause more logical reads? How does it change the SQL Server behavior? Like SQL Server may read more index page since it's in cache anyway?  Anyway, I disabled read ahead and issue the above query again. Now it reports the same amount of logical reads each time. BUT the logical reads is much smaller!!      Table 'lineitem'. Scan count 1, logical reads 404, physical reads 160, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.   So my question is, why the read ahead feature could cause many more and various logical reads count?  Out of curiosity, I tried another query without the "order by":      select top 100 * from dbo.lineitem   Here's the result without read ahead:      Table 'lineitem'. Scan count 1, logical reads 5, physical reads 3, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.   Here's the result with read ahead:      Table 'lineitem'. Scan count 1, logical reads 15, physical reads 2, read-ahead reads 3416, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.   The one with read ahead still has more logical reads. So, why?


I'm currently using the two Springer document classes llncs and svjour3. Both define their own theorem environments (not using amsthm), including their own proof environment. However, this proof environment does not automatically generate a qed symbol (box) at the end of each proof, as the proof environment of amsthm does. What's the proper way of automatically generating a qed symbol while using the theorem/proof environments provided by the Springer document classes?

Tomb stone (Q.E.D. mark) is not displayed at the end of a proof when I use "svmono.cls" for my dissertation. How can I enable it?  Here is the code example:  <\documentclass[12pt,sectrefs]{svmono}   \usepackage{makeidx}         \usepackage{graphicx}                               \usepackage{multicol}         \usepackage[bottom]{footmisc} \usepackage{amsmath} \usepackage{lipsum} \makeindex               \begin{document} \frontmatter \mainmatter  \chapter{Chapter Heading} \section{Section Heading} \subsection{Subsection Heading} \begin{theorem} \lipsum[1-2] \end{theorem} \begin{theorem}   nonses\\   nonsesnse\\   nonsesnse\\   nonsesnse\\   nonsesnse\\ %nonsesnse\\ \end{theorem}   \begin{proof}    here is the proof.  \end{proof}   \end{document}


Cannot get my v600 usb scanner to work. Looking for epson drivers, I found . I downloaded drivers there :   iscan_2.29.1-5~usb0.1.ltdl7_amd64.deb iscan-data_1.23.0-1_all.deb   and installed them. But my scanner is still not recognized. I use ubuntu 13.04. simple scan, iscan or xsane scan  can not see the device.

I installed the driver for : iscan-data_1.13.0-1all.deb as well iscan_2.28.1-3.ltdl7_i386.deb But the scanner does not work. How can I install the scanner drivers?


My processor' frequency is 1.7 GHz and i want to add 4 GB RAM to my system.I want to know that RAM  what speed should i buy so that it is compatible with my processor and why ??

I am seeking advice on which memory to use with my motherboard and CPU. Below are my components and some relevant information extracted from their official websites.   NOTE: Although this is a very specific case, a general answer is equally good for me — and also alot more useful for everyone else!  CPU: AMD Phenom II X4 810   ASUS M4A785TD-V EVO listed as one of many  motherboards.   Motherboard: ASUS M4A785TD-V EVO   4 x DIMM, Max. 16 GB, DDR3 1800(O.C.)*/1600(O.C.)/1333/1066/800 ECC,Non-ECC,Un-buffered Memory Dual Channel memory architecture (Complete list of specs: ).   NOTE II: I wouldn't want to do any overclocking as I have no experience with that. So I think the 1333 MHz is the most appropriate. Since the higher frequencies are marked with "O.C."  Questions:   How can I be certain that a specific RAM will work well (or not work) together with my CPU and motherboard? (The Qualified Vendor List is a good starting point, but it's a bit limited and sometimes a bit outdated). Is it true that choice of memory is not independent of the processor? How?    I'm worried I'll be missing something essential when buying my next RAM chips :)


I was playing  with an opponent who would often 'take back' or 'adjust' moves.  In general I'm OK with this if:   The player is new to the game It is a minor tweak on a part of the board that doesn't effect me directly (e.g. changing your mind on what planets to exhaust to pay for units)   The problem is that this player doesn't satisfy either of my criteria, because:   The player actually owns the copy of  that we're playing The 'take backs' involve changing how many units to commit to battle after that combat has been resolved   During the game I expressed my displeasure, which was heard by the table. It's the only time I've seen a player be eliminated from the game. Obviously the player didn't like this, so 2 of the 6 players didn't have a great time.  So, my question is how can I encourage a 'no take backsies' policy in the game?

A generic question across most board games: once a player has taken their turn (taken their finger off the piece they are playing), should they be allowed to change their mind?  Similarly, if a player forgets to take a privilege, such as an occupied building in Puerto Rico giving an extra worker, or plantation, if they remember a few moves later, should they be allowed to take the privilege?  Very few rules explicitly express how these events should be dealt with, so they are generally left up to the group. However, my group's rules will change depending on the personality of the players playing (not all members are available each time we play). I would like to make this consistent, and would appreciate feedback on how others deal with this scenario.


Reviewing someone's code, in a non-static class, I noticed there were only private static methods. So those are used internally in its class.   interface IDogInterface {     void Bark(bool isBarking); }  public class GoldenRevier : IDogInterface {     public void Bark(bool isBarking)     {         //Implementation...          SomeMethod();         SomeOtherMethod();         AnotherMethod();     }      private static void SomeMethod();     private static void SomeOtherMethod();     private static void AnotherMethod(); }   Note: there are no static attributes, no getters or setters, only what you saw in the above code.  Why would you make those internal methods static ? I see no benefit doing this.  I see bad logic in the above code... Am I missing something ?  EDIT:  Code edit to highlight the accepted answer meaning.  public class GoldenRevier : IDogInterface {     private Bark _bark = new Bark();      public void Bark(bool isBarking)     {         if(isBarking)         {             _bark.SetLoudness(5);             _bark.Start();         }         else         {             JustChilling();         }     }      private static void JustChilling()      {           Console.Write("No barking today, just chilling!");     } }

ReSharper likes to point out multiple functions per ASP.NET page that could be made static. Does it help me if I do make them static? Should I make them static and move them to a utility class?


This is a seemingly basic mechanics problem but I'm having a dilemma in understanding what happens. You start with two blocks, one on top of the other (the bottom block has a larger mass than the top block). There is friction between the blocks, so they stick together. These two blocks rest on a frictionless surface. If I apply a force F to the top block, what happens?  Drawing the free body diagram, the force F I apply is counter acted by a frictional force f because of the friction between the two blocks. Additionally, this frictional force will be opposed by another frictional force on the bottom block that forces it in the direction I applied the force. Thus, we see that the blocks will move in the direction I have pushed.  HOWEVER, I can't understand why the top block will move forward as well. The force I have applied should be negated by the frictional force, but this is not the case. Clearly, the block accelerates forward despite the friction. Why is this paradox created???

Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?


Running the following command:  $ df -h   Gives the following output:  Filesystem                        Size  Used Avail Use% Mounted on /dev/md2                           91G   85G  1.2G  99% /home   Which means out of the 91 total only 85 is used, which should leave 6 Avail (91 - 85 = 6). Why is Avail only 1.2?  This question is explicitly about the contradiction between the Used - Size and the Avail column in df output as opposed to a discrepancy between df and du output such as in . In my case there are no deleted files still in use on the filesystem.

This is a RHEL server, I'm running a MySQL server on it, the database and log files (however, logging is disabled) are located on the /srv directory where plenty of space is available.  Recently I had a crashed table, so I tried fixing it but on the next day I found that MySQL can't respond to many of queries with an error indicating that there is no disk space:  ERROR 1030 (HY000): Got error 28 from storage engine   So I ran the following command to see what's taking space  [root@tms /]# df -h Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/server-slash                       9.9G  9.5G     0 100% / tmpfs                 7.8G     0  7.8G   0% /dev/shm /dev/sda1             485M   58M  402M  13% /boot /dev/mapper/server-var                       739G  252G  450G  36% /srv   Surprisingly it's the / directory. But more surprisingly is that the directories under / do not indicate used space more than 2 GB, while df shows total space 9.9 GB for /.  [root@tms /]# du -sh /* 7.5M    /bin 48M     /boot 200K    /dev 24M     /etc 4.0K    /home 223M    /lib 21M     /lib64 16K     /lost+found 4.0K    /media 4.0K    /mnt 183M    /opt ...deleted some file-not-found errors for files under /proc 0       /proc 144K    /root 14M     /sbin 4.0K    /selinux 252G    /srv 0       /sys 44K     /tmp 917M    /usr 259M    /var   So why does df show wrong values ? And how can I findout what's actually taking space ?


we need to Prove that $8(5)^n+6(3)^{2n}−80n−14$ is divisible by $512$ for all n∈N by induction. I started by base case $n = 1$. Then I took for $k$. Not able to prove true for $k+1$. Please help. Thank you for your time

Note: question was updated to correct the constant term $-14$ (vs. $-40$). We need to prove that $8(5)^n + 6(3)^{2n} - 80n - 14$ is divisible by $512$ for all $n \in \mathbb{N}$. I started by taking $n = 1$, then for $n = k$ and then for $n = k+1$. I am stuck here. Not able to solve further but still trying. What to do next? Thanks for your time.


I imported this model from Maya, though the mesh is still "Weird" in Maya. I'm unaware of the issue. The hand mesh I used has this shading problem, it also messes up the AO bake I try to do. Though I'm using smooth shading the flat shading shows the problem I suppose. How can I fix this?  [][[]

hi, why the model looks weird. no double face or normal flip?  I include the blender file


I have an application which I was running by using  ./cmd from the directory where it is located. Now what I am looking for something by which the application starts automatically when my system boots up. I came across some suggestion saying write a script, do something in init.d, etc. But I am not able to reach a clear solution.  Request you kindly provide your valuable suggestion on same.

How can I run scripts automatically when Ubuntu starts up so I don't have to run them manually after startup?


I have been debating whether to get a nexus 5 phone since it came out. My only fear is that I won't like android. I love ubuntu, I know that I'd love ubuntu. So I have a few question related to Ubuntu Touch:  Is it easy or possible to switch between Ubuntu Touch and Android? Would I have to keep hacking the phone? Can I dual boot them? Would I lose my data every time I switch?  The nexus 5 isn't mentioned here:  Does that mean it simply won't work if I follow the porting instructions? Would I have to do a bit of hacking? Has anyone got it working? Will it eventually be supported?

With the announcement of the Ubuntu Phone OS I'd like to know what phone (and tablet) models are supported at this time.  Note from foss & Oli: We are making this the master question for all future "Will this work on <insert random tablet/phone/device here>?!" questions


Let $\textsf{FinVec}$ denote the category of finite-dimensional real vector spaces. For each vector space $V \in \textsf{FinVec}$, choose a vector space isomorphism $\varphi \colon V \to \mathbb{R}^{\dim V}$ and endow $V$ with the standard smooth structure from $\mathbb{R}^{\dim V}$ pulled back along $\varphi$. I think (correct me if I'm wrong!) that this smooth structure on $V$ is independent of the choice of $\varphi$ up to diffeomorphism.    Definition Let $n \in \mathbb{N} \cup \{\infty\}$ (where we use the convention that $\mathbb{N}$ includes $0$). A functor $F \colon \textsf{FinVec} \to \textsf{FinVec}$ is called $C^n$ iff $$f \mapsto F(f) \colon \operatorname{Hom}(V,W) \to \operatorname{Hom}(F(V), F(W))$$ is a $C^n$ function for all $V,W \in \textsf{FinVec}$ (where the smooth structures on the hom sets are the ones described above, as these hom sets are finite dimensional real vector spaces under pointwise addition & scalar multiplication).    Of course, any $C^n$ functor is also $C^m$ whenever $m \leq n$, and in particular $C^\infty$ functors are $C^n$ for all $n$. Examples of $C^\infty$ functors include:   $\operatorname{Hom}(V,{-})$ for any $V \in \textsf{FinVec}$ $V \otimes {-}$ for any $V \in \textsf{FinVec}$ The exterior algebra functor   However, I've been unable to think of any examples of an endofunctor of $\textsf{FinVec}$ which is not $C^\infty$! So:  Does there exist an endofunctor of $\textsf{FinVec}$ which is not $C^\infty$?  If the answer is yes, then my follow-up questions are:  Does there exist an endofunctor of $\textsf{FinVec}$ which is not $C^0$? If $n,m \in \mathbb{N} \cup \{\infty\}$ with $m < n$, does there exist an endofunctor of $\textsf{FinVec}$ which is $C^m$ but not $C^n$?

Let $\mathbf{FinVec}$ denote the category of finite-dimensional real vector spaces and linear maps, let $F\colon\mathbf{FinVec}\rightarrow\mathbf{FinVec}$ be a functor. For each pair of objects $V,W$, the Hom-set $\operatorname{Hom}(V,W)$ is itself a finite-dimensional vector space and we equip it with the unique structure of a topological space/of a smooth manifold that is compatible with its vector space structure. The composition maps are then continuous/smooth. In this way, we view $\mathbf{FinVec}$ as enriched over the category $\mathbf{Top}$/$\mathbf{Diff}$ respectively. It then makes sense to ask whether the functor $F$ is enriched over $\mathbf{Top}$/$\mathbf{Diff}$. That is just to ask whether the induced map $F\colon\operatorname{Hom}(V,W)\rightarrow\operatorname{Hom}(FV,FW)$ is continuous/smooth for all $V,W$. (Irrelevant to the rest of the question, but the reason this is a useful notion is that it is the natural hypothesis assuring that the functor induces another functor on the category of topological/smooth vector bundles, applying the original functor fiberwise.) In the case $V=W$, by functoriality, we can restrict $F$ to a group homomorphism $\operatorname{GL}(V)\rightarrow\operatorname{GL}(V)$. If the functor is continuous/smooth, so is this map. Note that $\operatorname{GL}(V)$ is a Lie group. It is a general result that a measurable group homomorphism between Lie groups is automatically smooth. This begs the following questions:  What's an argument for the existence of functors that aren't continuous? Can we construct one? Given the above, it either happens that the restrictions to $\operatorname{GL}(V)\rightarrow\operatorname{GL}(V)$ are continuous and continuity fails elsewhere, or the induced maps will be non-measurable, so that the construction will necessarily have to involve choice to some extent. Are there continuous functors that aren't smooth? Given the above, a continuous functor will have smooth restrictions to $\operatorname{GL}(V)\rightarrow\operatorname{GL}(V)$, but smoothness may fail elsewhere.


Let $S=\{1,2,3,4,5....,2070\}$ and $A$ be the number of subsets of $S$ whose sum of elements in $S$ is divisible by $9$.If $$A=\frac{2^a\left(2^b+1\right)}{c}$$then find the values of $a,b$ and $c$.  The given solution is quite cryptic:  Let $f(x)=(1+x)(1+x^2)(1+x^3)....(1+x^{2070})$.  Then $A$ must be the sum of coefficient of $x^{9k}$ where $k$ is non-negative integer.So, $$A=\frac{2^{2070}+8.2^{230}}{9}$$How has the author of this question calculated this expression

Let $S={1, 2, 3, 4, ....., 2070}$ find the number of subsets of $S$ whose sum of elements in $S$ is divisible by 9     In the expression $$f(x)=(1+x)(1+x^2)......(1+x^{2070})$$    Terms of the form $x^{9k}$ will be the subsets divisible by 9. I am not able to proceed from here.


Intuition tells me that a bigger lens will collect more light with the same f-number than a small lens. But photographers tell me I am wrong. I cannot understand why.  There are quite a few posts both on SE (e.g.  and ) and elsewhere addressing this question. But I fail to understand it and would appreciate if someone could answer it slightly differently (ideally without photographic terminology, but from the purely optical perspective). For simplicity, let's say that we are trying to image an object located at infinity. Its image will be a single on-axis pixel on our camera sensor.     All rays passing through the lens will end up on the same pixel. The amount of light landing on this pixel will be proportional to the entrance pupil area and will not depend on the focal length of the lens. Thus, we can change the f-number (which is the f/D ratio) without changing the amount of light on the sensor. Why do they say then that the amount of light is the same for all lenses with the same f-number (for example, )?   (I know about the T-stop number, but let's ignore the transmission for the moment. I am interested in geometrical treatment only.)

I never understood what the f really stands for in the f-stop values, like f/1.8. Wikipedia explains it in various articles, but I still find it very confusing. What I understand, though, is that it has something to do with focal length.  Should I assume, therefore, that bigger focal lengths capture more light? For example, should 85 mm f/1.8 lens capture a lot more light than for example 24 mm f/1.8?  References to back up my confusion:  The article about  goes on to claim:     The amount of light captured by a lens is proportional to the area of   the aperture, equal to:            Where f is focal length and N is the f-number.   The "f-number" is mentioned here. But the article about  claims:     In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter.   This seems very recursive. Why does the aperture article refers to both the focal length and the f-number, when the latter article claims that f-number already carries the property of focal length?  What's going on here?


How should I solve this problem? can anyone help?  Thanks.

I have trouble coming up with combinatorial proofs. How would you justify this equality?  $$ n\binom {n-1}{k-1} = k \binom nk $$ where $n$ is a positive integer and $k$ is an integer.


After the release of the Halloween Update for Clash of Clans, I noticed a new trap (the Skeleton Trap) had been created. The cost to upgrade them is pretty expensive (600,000 gold is insane), so is there any information regarding the duration of the Skeleton Trap?

In the Upcoming Halloween Update Posted By SOOPUR SELL (supercell), there have been sneak peeks released showing new skeleton traps for TH 8+. I also remember the Santa Strike from one of the Christmas Updates. My question is when these holiday events finish, do we lose the money we spent on the Traps or do we keep them forever?


I have a system which has triple booted Windows 10, Ubuntu 16.04 and Kali Linux. I installed them in that order, so right now when I turn on the computer the GRUB from Kali Linux is what loads.   I want to uninstall Kali Linux which is the easy part. I'll just delete the partition which has Kali and it's done. But how do I restore the GRUB of Ubuntu so that I can boot Ubuntu or Windows from the bootloader menu?

I have Windows 10, Ubuntu 16.04 and Kali installed. The grub is of Ubuntu. I would like to remove Kali but I have no idea as to how to do it. Can someone help me ?


OS X is my host OS.  I have windows xp and Ubuntu 10.10 on guest OS. They both work great.  When I eject USB flash drive from host OS, it appears in windows guest OS  but it does not appear in Ubuntu Guest OS.   I never run both guest OS at the same time. It's always either or.  I am running, VM VirtualBox 4.1.10 and installed latest guest additions and also installed VM virtualbox extension pack.

I'm using Ubuntu Maverick and Virtual Box 3+. I have Windows 7 Ultimate. The problem is that it doesn't detect USB drives in Windows 7, but USB peripherals (mouse + keybord) are working.  I followed , but I can't find the user group vboxusers. How can I continue? I would also like to upgrade to the latest version without any risk (without losing my virtual hard disk drive).


I am  using SP2010 and I have a javascript that I am using to change color of a button in my document library. I have added an input button in a library column, which is calling javascript onclick. My problem is changing the color of first item button but not letting me change the button color of another item button. Below is the script I am using, I copied it from one of the sites. I am not really good at coding but I understand this requires a little bit of tweaking and event-listener to save the color of the button. I don't understand why I can't change the button color of other buttons for other items.   My requirements are Button changing color and once its changed unless again clicked on will not change the color upon refresh or closing of page. I posted a question before but I didn't want to use the same thread so creating a new question (I hope its okay). Thanks so much for all the help.     E.G. Columns I have currently in my document library Type, Name, Button, Date  <script> function setColor(btn,color){    var property=document.getElementById(btn);   if (window.getComputedStyle(property).backgroundColor == 'rgb(244, 113, 33)') {     property.style.backgroundColor=color;   }   else {     property.style.backgroundColor = "#f47121";   } } </script>     Here is what I am looking for, I have the view above and all I want user to do click on red button and it will turn green and it will save with that color so next user will see that button is green.

I have a document library where the CEO wants to see three buttons. If he has read the document he wants to click on Yes, otherwise it will always be No. If he clicks Flag it means it needs to be discussed. How can I have three buttons where he can simply push it and he wants that to be color coded. He is using safari on ipad and would not change that; therefore all the easy options I had for him are not going to help . Is there a javascript I can use so when he clicks the Yes button it turns green and when he clicks No it remains red. I have searched everywhere for an answer and I can't find one. I am not good at coding and just a beginner so still learning but this one is becoming a hard task doesn't seem hard but for me it is.   He does not want to go into edit view to complete the task as he says its too many clicks and of course since its its on ipad it is bit harder than working a computer.  I am thinking of adding one button with three colors, First one will always be no so red and onclick it will become green and if he clicks it again it will become black. Is there a javascript that can add a button in a column and have the user just click on it with their mouse and no editing required?   Thanks in Advance.


I do have a rather basic question. Does one say: "Flow rates correlations" or "Flow rate correlations" in English. Is there some specific rule to follow here?

I am writing a neural network application. In this application, a neural network can have one or more hidden layers, which can have different sizes (neuron counts).  Which label would be correct: "hidden layer sizes" or "hidden layers sizes" and why? I realize this is a more general grammar related question and I'd love to learn about it.  EDIT: the label is for a text box, where user will enter numbers separated by commas.


\documentclass{article} \usepackage{tikz} \usetikzlibrary{calc}  \begin{document} \begin{tikzpicture}         \coordinate (A) at (-10,0);         \coordinate (B) at (0,0);         \coordinate (C) at (0,5*sqrt(2*sqrt(2)-2));         \coordinate (D) at (-5-5*sqrt(2),5*sqrt(2*sqrt(2)-2));         \draw (A) -- (B) -- (C) -- (D) -- (A) -- (C); \end{tikzpicture} \end{document}

I want to use parentheses in coordinate calculation in tikz. There should be a simple way, but I couldn't find it. For example,  \def\x{10}; \draw (0,0) -- (1+1/\x,0);   this works fine. But,  \def\x{10}; \draw (0,0) -- (1+1/{\x+1},0);   this doesn't work. Other parentheses didn't work either. What is the expression for parentheses?


I'm writing the bibliography. LaTeX don't write it well. I don't know why. I have tried the tow methods: \begin{thebibliography} and using BiBTeX. The result is the same.  The result is longer spaces between some words.      Anybody can help me? Thanks!

I'm writing the bibliography. LaTeX don't write it well. I don't know why. I have tried the two methods: \begin{the bibliography} and using BiBTeX. The result is the same.  The result is longer spaces between some words.     Using the first method(without BibTeX). The first entry at the image is:  \bibitem{Stack1} Stack Overflow. \tit{Simple Bluetooth data receiver Android}. \url{http://stackoverflow.com/questions/9164138/simple-bluetooth-data-receiver-android}.   \tit{} is like \textit{}  I have written a small example:  \documentclass[12pt,a4paper]{book}  \usepackage[utf8]{inputenc}  \usepackage[left=1.8in,right=1.8in,top=0.6in,bottom=0.6in]{geometry}   \usepackage[pdftex,bookmarksnumbered,hidelinks,breaklinks]{hyperref}   \begin{document}  \begin{thebibliography}{99}  \bibitem{Dani} Daniel García. \textit{Activando y desactivando el bluetooth en Android}. \url{http://danielggarcia.wordpress.com/2013/10/19/bluetooth-i-activando-y-desactivando-el-bluetooth-en-android/}. \end{thebibliography}  \end{document}   And the result is


Please show me how to use "not in" using LINQ  Given the SQL :   select count(*) from Customer where (ID = @Id and substring(CustomerIndicator, 1, 1)  not in(@custInd1, @custInd2, @custInd3))   My Attempt:          var results = (from r in dt.AsEnumerable()                        where r.Field<string>("ID") == row["ID"].ToString()                             && !(r.Field<string>("CustomerIndicator").Substring(1, 1) == "X" || "Y" || "Z")                        select r).Count();

I have two collections which have property Email in both collections. I need to get a list of the items in the first list where Email does not exist in the second list. With SQL I would just use "not in", but I do not know the equivalent in LINQ. How is that done?  So far I have a join, like...  var matches = from item1 in list1 join item2 in list2 on item1.Email equals item2.Email select new { Email = list1.Email };   But I cannot join since I need the difference and the join would fail. I need some way of using Contains or Exists I believe. I just have not found an example to do that yet.


Let be $u$ a numerical function defined over $\Omega$, with $u$ measurable, and let $(O_i)_{i\in I}$ be a family of all open sub-sets $O_i$ of $\Omega$, such that $u=0$  almost always except on a set of measure $0$ in $O_i$. Let $O = \cup_{i\in I}O_i$ (Then $u=0$ almost always except on a set of measure in $O$). How can I define in explicit form the set $\Omega\setminus O$?   I trying this ...  $\Omega\setminus O = \{x\in \Omega; (u(x)=0 \text{ and } x\in K\subset \Omega, \text{ where } K \text{ is closed}) \text{ or } (u(x)\neq 0)\}$.  This is correct?

Let be $u$ a numerical function defined over $\Omega$, with $u$ measurable, and let be $(O_i)_{i\in I}$ a family of all open sub-sets $O_i$ of $\Omega$, such that $u=0$ often in $O_i$. Let be $O = \cup_{i\in I}O_i$. Then $u=0$ often in $O$.  How I can be able to do this?.  I am beginning make ...  Let be $u$ defined than $0$ in $O_i\setminus M_i$ and $\neq$ $0$ in $M_i$, then   $O = \cup_{i\in I}O_i=\cup_{i\in I}[(O_i\setminus M_i)\cup M_i]$, ...  but I don't know how find the subset of $O$ such that have measure zero.


Anyone who knows their way around a Windows machine knows about naming items aux, con, nul, etc etc. Its impossible unless you use third party software or command line.  Long story short: I made a batch file that makes a couple hundred files per second, all of which are named "aux.txt%random%...".   So now I have 600+ files I can't delete. At all. My laptop is dual booted with Linux, but Windows 10 makes the C: drive read only so that won't help.  I'm at a complete loss! I know it was stupid to even try doing this, and that I should've used a VM, but I was just in the moment of testing the lengths of Windows. I must delete these files because they are taking up too much space!!  An example file name is "aux.txt29582001129920227490210248486001047729"

I have a Windows XP box (NTFS filesystem) on which I found a file named NUL. I have not been able to remove this file in any usual way. The file appears to be owned by Administrator in the SYSTEM group, unlike any other file in the same directory (the other files are owned by my user id).  How do I get rid of this file? Where did it come from?


I have a problem with the spacing in the header of a subsection. Only this particular heading has large spaces. It looks like this:    Here is MWE:  \documentclass[11pt,twocolumn]{article}  \begin{document}  \section{Implementation}  \subsection{Reciprocal Velocity Obstacle (RVO)}   \end{document}   How do i fix this?

I have a problem, this is what it looks like:     And this is the code:  \subsection{Bakterienst\"amme und Anzuchtbedingungen}   Where does the huge whitespace come from?


Use mean value theorem to prove the inequality:  $$\frac{|x+y|}{1+|x+y|}\leq\frac{|x|}{1+|x|}+\frac{|y|}{1+|y|}\quad \forall\, x,y\in\mathbb{R}$$  I have no idea which function I should consider to apply the theorem. I tried $\ln(|1+x|)$, but this function is not defined at $-1$.

Is $\frac{\vert x+y\vert}{1+\vert x+y\vert}\leq\frac{\vert x\vert}{1+\vert x\vert}+\frac{\vert y\vert}{1+\vert y\vert}$ true for all $x,y\in\mathbb{R}$?  If not, how can I prove that $\int\frac{\vert f-h\vert}{1+\vert f-h\vert}\leq\int\frac{\vert f-g\vert}{1+\vert f-g\vert}+\int\frac{\vert g-h\vert}{1+\vert g-h\vert}$? I tried C-S: $$\sum_{cyc}\frac{|x|}{1+|x|}=\sum_{cyc}\frac{x^2}{|x|+x^2}\geq\frac{(x+y)^2}{x^2+y^2+|x|+|y|}.$$ Thus, it's enough to prove that $$\frac{(x+y)^2}{x^2+y^2+|x|+|y|}\geq\frac{(x+y)^2}{|x+y|+(x+y)^2}$$ or $$|x+y|+(x+y)^2\geq x^2+y^2+|x|+|y|,$$ which is wrong for $(x,y)=(1,-1).$


RENAME DATABASE sample TO sample_db; 1 queries executed, 0 success, 1 errors, 0 warnings Query: RENAME DATABASE sample TO sample_db Error Code: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DATABASE sample TO sample_db' at line 1 Execution Time : 0 sec Transfer Time  : 0 sec Total Time     : 0.001 sec

The MySQL manual at  covers this.  Usually I just dump the database and reimport it with a new name. This is not an option for very big databases. Apparently RENAME {DATABASE | SCHEMA} db_name TO new_db_name; .  This needs to work with , which stores things very differently than .


Let $a_n$ be a bounded sequence. Prove that $$\limsup_{n\to\infty}(a_n)\le \sup(a_n)$$   So I think that the best way to prove it is assume that $\limsup_{n\to\infty}(a_n)> \sup(a_n)$ and then find element of sequence > $\sup(a_n)$, that is wrong because it's $\sup(a_n)$.  But I don't really understand how to write it correctly in "math" language with $\epsilon$.

Proposition: Let $(a_n)_{n=1}^\infty$ be a sequence of real numbers. Show that $\limsup_{n\to\infty} (a_n)\leq \sup(a_n)_{n=1}^\infty$.   Any hints on how to prove it will be appreciated.


I'm writing a script in Python that should communicate with a software "ConsoleApplication.exe"(wrote in C); this last one once started waits for a fixed lenght command(5 bytes) from his "stdin" and generates (after 2-3 seconds) on  his "stdout" an output that I should read on my Python script.  #  //This is the "ConsoleApplication.c" file #include <stdio.h> #include <function.h>  char* command[5]; int main() {  while(1)  {   scanf("%s\n", &command);  output = function(command);  print("%s\n", output);   } }   #  #this is Python code  import subprocess #start the process p = subprocess.Popen(['ConsoleApplication.exe'], shell=True, stderr=subprocess.PIPE) #command to send to ConsoleApplication.exe command_to_send = "000648" #this seems to work well but I need to send a command stored into a buffer and if Itry  #to use sys.stdout.write(command_to_send)nothing will happen. The problem seem that #sys.stdout.write expect an object I/O FILE while True:     out = p.stderr.read(1)     if out == '' and p.poll() != None:         break     if out != '':         sys.stdout.write(out)         sys.stdout.flush()   #  Any suggestions? How can I fix it?  I tried to use    stdout = p.communicate(input='test\n')[0]    but Im getting the following error at runtime: "TypeError: 'str' does not support the buffer interface" I also tried this  from subprocess import Popen, PIPE, STDOUT   p = Popen(['ConsoleApplication.exe'], stdout=PIPE, stdin=PIPE, stderr=PIPE)  out, err = p.communicate(input='00056\n'.encode()) print(out) out, err = p.communicate(input='00043\n'.encode()) print(out)   but I get this error: "ValueError: Cannot send input after starting communication"

If I do the following:  import subprocess from cStringIO import StringIO subprocess.Popen(['grep','f'],stdout=subprocess.PIPE,stdin=StringIO('one\ntwo\nthree\nfour\nfive\nsix\n')).communicate()[0]   I get:  Traceback (most recent call last):   File "<stdin>", line 1, in ?   File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 533, in __init__     (p2cread, p2cwrite,   File "/build/toolchain/mac32/python-2.4.3/lib/python2.4/subprocess.py", line 830, in _get_handles     p2cread = stdin.fileno() AttributeError: 'cStringIO.StringI' object has no attribute 'fileno'   Apparently a cStringIO.StringIO object doesn't quack close enough to a file duck to suit subprocess.Popen.  How do I work around this?


In Hamill's "A Student's Guide to Lagrangians and Hamiltonians", section 5.2, the equations for a canonical transformation $(q,p) \to (Q,P)$, induced by the generating function $F(q,Q,t)$ are derived using the principle of stationary action and the fact that the equations of motion are indifferent to the addition of a complete time derivative $d{\Lambda}(q,t)/dt$ (not a function of $\dot{q}$!) to the Lagrangian; this indifference being because the small variations $\delta q$ to the extremal path vanish at the endpoints.  In particular, the author states that:  $\delta \displaystyle\int_{t_1}^{t_2} \left( P\dot{Q} -K(Q,P) \, + dF(q,Q,t)/dt \right)dt = \delta \int_{t_1}^{t_2} \left( P\dot{Q} -K(Q,P)\right)dt$  (where $K$ is the new Hamiltonian) because supposedly we have: $$\delta\int_{t_1}^{t_2} (dF(q,Q,t)/dt)dt=\delta \left(F\left(q(t_2),Q(t_2),t_2\right)-F\left(q(t_1),Q(t_1),t_1\right)\right)=0$$  for the reasons stated above for $\Lambda$.  I don't understand why this can be assumed. In general, $q$ may be a function of both $Q$ and $P$, and the small variations of $P$ at the endpoints need not necessarily vanish, and therefore $F$ may obtain different values at the point $t_1$ (and of course at $t_2$) for different variations of $Q$..  All this can also be stated in terms of $q$ and $\dot{q}$, in which case I would say that since $Q$ is a function of $q$ and $p$ (and $p$ is a function of $\dot{q}$), we get $F(q,\dot{q},t)$ which may vary at the endpoints since $\delta \dot{q}$ need not vanish at the endpoints.  This is an important step in the derivation of a canonical transformation using a generating function... What am I missing?

This might be a stupid question, but I just don't get it. In Hamiltonian mechanics when examining conditions for a $(\boldsymbol{q},\boldsymbol{p})\rightarrow(\boldsymbol{Q},\boldsymbol{P})$ transformation to be canonical one starts with $$ \dot{q}_ip^i-H(\boldsymbol{q},\boldsymbol{p},t)= \dot{Q}_iP^i-\bar{H}(\boldsymbol{Q},\boldsymbol{P},t)+\frac{d}{dt}W(\boldsymbol{q},\boldsymbol{Q},t)$$ where $\bar{H}$ is the transformed Hamiltonian, and $W$ is the generating function (now a function of $\boldsymbol{q}$ and $\boldsymbol{Q}$). This term shouldn't break Hamilton's principle, since $$ \delta\int_{t_1}^{t_2} dt\frac{d}{dt}W(\boldsymbol{q},\boldsymbol{Q},t)=\delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_2}-\delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_1}=0-0=0 .$$ But I don't see why the variation of $W$ should disappear at the endpoints (say at $t_1$). Expanding leads to: $$ \delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_1}=\left(\frac{\partial W}{\partial q_i}\right)_{t_1}\underbrace{\delta q_i(t_1)}_{=0}+ \left(\frac{\partial W}{\partial Q_i}\right)_{t_1}\delta Q_i(t_1)=\left(\frac{\partial W}{\partial Q_i}\right)_{t_1}\delta Q_i(t_1).$$ $\boldsymbol{Q}$ is itself a function of $\boldsymbol{q}$ and $\boldsymbol{p}$, so $$ \delta Q_i(t_1)=\left(\frac{\partial Q_i}{\partial q_k}\right)_{t_1}\underbrace{\delta q_k(t_1)}_{=0}+\left(\frac{\partial Q_i}{\partial p_k}\right)_{t_1}\delta p_k(t_1)=\left(\frac{\partial Q_i}{\partial p_k}\right)_{t_1}\delta p_k(t_1). $$ It seems as if we also needed the variation of $\boldsymbol{p}$ to vanish at the endpoints, and I don't get this because (at least in cartesian coordinates) $\boldsymbol{p}=m\dot{\boldsymbol{q}}$ and the velocity can be different along the original and the varied orbitals even at the endpoints (they can point in totally different directions), so in general $\delta \dot{\boldsymbol{q}}(t_1)\neq 0$. What am I doing wrong? Can someone help me with this, please?