The trackpad's click often fails during normal use.   It fails when the computer is used in a horizontal position flat on the table, but when the computer is tilted at a 45º angle the click starts working again.    The computer has gone to sleep twice in the middle of use.   Now every time I wake the computer up from sleep, the computer's screen flashes green or with a pixelated image, and the trackpad and keyboard do not work, so I have to force shutdown and do an SMC restart.   I was using El Capitan when the problems started, and now I have updated to High Sierra with no improvement.   I used cocnutBattery to assess the battery health in case of swelling, but it says the battery is completely healthy. Apple diagnostics also couldn't detect any problem.   I have tried the NVAM and SMC resets many times to no avail.   Any suggestions?

This discovery came after my latest question:   I use my macbook on a stand with good airflow, after High Sierra, I noticed unusual high heating along with poor gpu performance, afterwards I noticed screen damage, and now, I discovered that my macbook is physically swollen, 2-3mm's I'm guessing  The issues could be unrelated to High Sierra, yet, it would be too big of a coincidence if it's not the cause, as things were breezy beforehand  Here's a picture of the issue:     The trackpad area is swollen, the trackpad doesn't click any more, the battery reports "Normal" condition (Cycle count: 12), the lid doesn't close any more, but everything luckily works for now  I assume it's the battery that's swollen, but even with the high heating I complain about, the GPU temperatures was 80C at most and enclosure temps weren't extremely high  It's a shocking issue for me, I'm wondering whether there is a solution other than buying a new Macbook, unsure how to approach the issue in general, and since I use the device daily, really don't want to part with it even for repairs or inspection, I'm located in Turkey  Also curious why I experienced these issues with High Sierra and whether anyone else has similar experiences


How and where can I catch Zekrom and Reshiram in Pokemon Alpha Sapphire and Omega Ruby?

There are a lot of legendaries available in ORAS, however a lot of them will only show up/be available if certain prerequisites are met.  I know Groudon/Kyogre are available through the Story, and      Rayquaza & Deoxys   through the postgame Delta episode, but what about the other available legendaries? What do I need to do to catch them?


Show that $\int _0^x\left[\int _0^tf\left(u\right)du\:\right]dt\:=\:\int _0^x\:\:f\left(u\right)\left(x-u\right)du$ EDIT: (USING integration by parts) Okay I think I have few ideas how to do this. I am confident that I need to use integration by parts. So $\int \:uv'=uv-\int \:u'v$ Let $u = [\int _0^tf\left(u\right)du \space]$  and $v'$ = 1 Now problem is with the notation and how everything is setup. There are so many variables, the $x$, the $u$ and the $t$.  Now I am very confused how to find $u'$ and $v$. Would $u'$ be $f(t)$ or $f(u)$ or $f(x)$? and same goes with $v$, would this be $t$, $u$ or $x$ and how can you tell and differentiate?? Otherwise I can I can do the question.

Let $f:\mathbb{R}\to\mathbb{R}$ be a continuous function. Then $$\int_{0}^{x}\left[\int_{0}^{t}f\left(u\right)du\right]dt=\int_{0}^{x}f\left(u\right)\left(x-u\right)du$$ Hint: Prove that if $F'(x)=G'(x)\;\;\;\forall x\in \mathbb R$ and there exists $x_0$ such that $F(x_0)=G(x_0)$, then $F(x)=G(x)\;\;\;\forall x\in \mathbb R$ This is a true/false question BTW. I think I managed to solve it, but I completely ignored the hint which is usually a red flag. therefore I need your opinion. My way: Let $F\left(x\right)=\int_{0}^{x}f\left(u\right)du$ for all $x\in \mathbb R$. LHS: $$\int_{0}^{x}\left[\int_{0}^{t}f\left(u\right)du\right]dt=\int_{0}^{x}F\left(t\right)dt$$ RHS: $$\int_{0}^{x}f\left(u\right)\left(x-u\right)du\underset{\begin{cases} a=x-u & b'=f\left(u\right)\\ a'=-1 & b=F\left(u\right) \end{cases}}{\overset{I.B.P}{=}}F\left(u\right)\left(x-u\right)\biggr|_{0}^{x}+\int_{0}^{x}F\left(u\right)du=$$ $$\left(0-0\right)+\int_{0}^{x}F\left(u\right)du=\int_{0}^{x}F\left(u\right)du$$ Thus RHS=LHS. $\blacksquare$ My biggest concern was integrating by parts while $x$ is both in the integral itself and in the integral bound. thank you.


The latest kernel that I can find in the repository is 4.19.0. How can I install 4.19.1 in Ubuntu 18.10?  user@user:~$ sudo apt install linux-image- linux-image-4.15.0-1021-oem                  linux-image-gke linux-image-4.15.0-1024-oem                  linux-image-kvm linux-image-4.15.0-29-generic                linux-image-lowlatency linux-image-4.15.0-36-generic                linux-image-oem linux-image-4.18.0-1002-aws                  linux-image-unsigned-4.15.0-1021-oem linux-image-4.18.0-1002-gcp                  linux-image-unsigned-4.15.0-1024-oem linux-image-4.18.0-1003-azure                linux-image-unsigned-4.18.0-1002-gcp linux-image-4.18.0-1003-kvm                  linux-image-unsigned-4.18.0-1003-azure linux-image-4.18.0-10-generic                linux-image-unsigned-4.18.0-10-generic linux-image-4.18.0-10-lowlatency             linux-image-unsigned-4.18.0-10-lowlatency linux-image-aws                              linux-image-unsigned-4.18.13-041813-generic linux-image-azure                            linux-image-unsigned-4.18.14-041814-generic linux-image-azure-edge                       linux-image-unsigned-4.18.15-041815-generic linux-image-extra-virtual                    linux-image-unsigned-4.18.16-041816-generic linux-image-gcp                              linux-image-unsigned-4.19.0-041900-generic

Currently I'm running Linux-3.0 and I want to update it to Linux-3.3.1 the latest stable kernel release as mentioned at . Can I update to 3.3.1 in Ubuntu without any risk of crashes? I'm updating my kernel regularly as provided by the Update Manager..Currently I have Linux-3.0.0.17..Can I update?  NOTE:  The latest kernel version any user is supposed to use in Ubuntu is updated automatically via the Update Manager, so no action is normally required by user regarding kernel upgrades. What the question author is referring to is mainline kernel, see:


I often share my MacBook Pro's Ethernet connection with devices like a Raspberry Pi to log in via SSH and configure files  without using a screen, keyboard, etc.  My current method to find the IP is to ping the hostname. Example: Ping raspberrypi.local.  Recently, I have ran into problems where the hostname is unknown of the device, and I need to login, finding it's IP.  So, I try the command-line utility , which scans for devcies on your local network, but I had no luck finding the device. Fing seemed to only show devices that were on my wireless network.  Are there any suggestions to find local IP addresses of devices I plug into my Ethernet jack?

How can I view a list of devices that are connected to my Apple laptop via Internet Sharing (when it's enabled)? If a list doesn't exist, does Internet Sharing log DHCP requests and if so, where? Thanks.


Before marking this as a duplicate, please note:- I have already seen  and the discussion there does not answer my query. That question is about a error in the passport department side and hence easily corrected by them, but in my case it is my/my family's mistake and I would like to know the consequences of that. Please read below.  When I went to the PSK Chennai for renewal of my passport (P1) which was about to expire in less than a year from now, I was shocked to learn that I have another passport (P2) issued under my name in RPO Lucknow almost 18 years ago (ie. during my college time). As I do not have any recollection of the exact events (probably due to my Vitamin D/calcium deficiency ?!) and since my father has unfortunately expired 9 years ago, I dont have the exact account of the events that has led to this situation. But I can try to explain to the best of my knowledge why I am in this situation based on the events from my memory. As I was only 18/19 years old at the time these events happened, I was simply signing where my father asked me to sign without understanding much about what was happening. So, in the write up below I am going to be implying that my beloved father did most of the things !  First, my Father (and I) had applied for Passport P1 for me in RPO Chennai (my place of residence). But we did not know about the status of our application for more than 6 months. Assuming that the application had got rejected, and anxious that I need a passport to pursue my higher studies, my father who has not had any formal school education of any sort, must have been instructed by some travel agent to apply for a passport (P2) near my place of study.  At the end, Both passports P1 and P2 got delivered.  My Father must have been aware that one should not USE two passports and hence with this good intention he must not have informed me about the existence of P2 and put P2 away somewhere safe. He must not have been aware that not only should one not USE two passports, one should NOT even POSSESS two passports.   Though I was aware that it is not correct for a citizen of India to hold two passports, I was NOT aware of the existence of two passports under my name. Only last week, while applying for renewal of passport I learned that there is P2 issued to my name in RPO Lucknow. Guided by the Assistant Passport Officer and the Granting Officer in PSK to sincerely search for P2 at home and surrender it, I did an extensive search of my father's belongings and found it (!!!) along with my father's spiritual books (which had been untouched since the expiry of my father).   Will this affect the renewal of my primary passport P1, AFTER I surrender P2? Will there be any mention of this in my passport P1 (ie a black mark) potentially affecting my future travels ?

I applied for my first passport in March 2009 in Lucknow passport office. But it got stuck in the police verification. After 1 year, when I didn't get my passport I decided to cancel my application. And I did, a cancellation receipt was also provided to me.  Now, I applied for a new passport in 2010 in Ghaziabad passport office. And after 3-4 months, I got my passport without any issues.  After 1 year, in 2012, I got a mail saying that your passport has been dispatched from Lucknow passport office. I was shocked to see this, as I cancelled the application already.  Now, I have two passports. Is it illegal, what should one do in such scenario? I need to travel to the United States in June 2013, please suggest.


Why are the character with accent not recognized ?  \documentclass[a4paper]{article} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[french]{babel} \usepackage{comment}  \includecomment{withsolution}  \begin{document} \begin{withsolution} à \end{withsolution} \end{document}   returned error:  ! Paragraph ended before \UTFviii@three@octets was complete.   If I put it outside the comment environment, it works. Thanks for the help.

I noted that if I use comment.sty and a there is a block of text containing UTF8 characters inside a comment environment, the compilation aborts!  Minimal Example  \documentclass{article} \usepackage[T1]{fontenc} \RequirePackage[utf8]{inputenc}%this file is stored as UTF8 file! \RequirePackage{comment} \specialcomment{privateSolution}     {\begingroup\itshape\noindent\textbf{Solution}\\}     {\endgroup} %\excludecomment{privateSolution}%Use it to remove solutions!  \begin{document} \title{Comment.sty and UTF8 test file} \maketitle \section{UTF8 character test} In which alphabet characters àìùòè are common? \begin{privateSolution}     The Italian alphabet contains àìùòè. \end{privateSolution}  \begin{comment}     The Italian one! It contains àìùòè. \end{comment} \end{document}   Has anyone the same problem? Any workaround?  Thanks in advance.


This is a problem I have been slowly chasing down. At first I was using 10% caps that caused the poor output accuracy. After changing the capacitor to a 1% I thought the problem would be fixed, but it was not fixed.  Here is the circuit ignore values because they are old. Important values:  R1: 649 1% R2: 3.24k 1% C1: 10nf 1% (12063A103FAT2A) (ceramic) f = 1.44(R1+2R2)C1 Pw = .693(R1+R2)C1  After plugging all of this in I should get (mathematically) f = 20kHz with  Pw = 27u (the values I want.) In reality I get f = 18kHz and Pw=28us. This value is completely unusable for the application. I considered the surrounding circuit to possibly cause issues so I breadboarded just the 555 circuit. This circuit obtained exactly the same f and Pw as the one on the PCB. After some more digging I found that a small R1 could be the problem. I added two pots to the breadboard and picked some random R values. Then checked f and Pw vs the calculation and it had worse accuracy than the hand picked resistors. (I understand the pots could be the reason they were more wrong.) Is there anything I am doing wrong? Is there a better solution for this? I have a uC controlling other things, but I want to keep it isolated from this circuit because the load is a flyback circuit (20kV.)

I've noticed that whilst I have a well-known solution using an NE555, that IC doesn't fulfill my needs perfectly. Others have told me that the NE555 is very rarely an appropriate solution to one of the problems it's being used for.  What are the systematic problems with the NE555?  More specifically, I'd like to have a better (lower part count / complexity, better stability, lower power consumption) solution for the following typical applications:   One-off timer (Monostable Multivibrator) Ramp generator Dear versed reader: please extend this list with typical applications!


If a 25 pound ball is dropped from 20 feet at the same time as a 15 pound ball is dropped from 10 feet, will the 25 pound ball catch up to the 15 pound ball?

I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time.  According to Galileo, two bodies of different masses, dropped from the same height, will touch the floor at the same time in the absence of air resistance.  BUT Newton's second law states that $a = F/m$, with $a$ the acceleration of a particle, $m$ its mass and $F$ the sum of forces applied to it.  I understand that acceleration represents a variation of velocity and velocity represents a variation of position. I don't comprehend why the mass, which is seemingly affecting the acceleration, does not affect the "time of impact".  Can someone explain this to me? I feel pretty dumb right now :)


I am having trouble understanding why the hide and sneak attack rule is applicable to a rogue hiding at the corner of a long hall.  If a rogue shoots an arrow down the hall and hits his target on the first round then I would allow the sneak attack. The rogue then goes into hiding using cunning action. Except that his target knows that the attack came from down the hall. He is now prepared for the attack and knows it can come from only 1 place.  The rogue ducking back around the corner is no different than any other class shooting around a corner then ducking behind it. So why should the rogue even be able to hide and gain sneak attack again?  In this case I am seriously considering ruling that the rogue cannot use his hide and sneak attack because the rogues position is obvious. Can anyone give me another explanation for this situation that might be a counter to my ruling?

In our D&D 5e games, I am not sure how to handle the following situation relating to stealth:  Enemies are in a room. The rogue stays outside, stepping to the side in order to be able to hide. Now, can he attack the enemies inside the room with his bow while getting advantage and sneak attack?  In favor of sneak attacking one might say, that the enemies don't see him prepare and have little time to react to his attack.  On the other hand, they know where he is, they just can't see him.  Is the situation different with a pile of boxes, where they know he's hidden behind the boxes, but not from which end he will attack?


I need to deduce and explain this statement:  Consider all r-element subsets of the set $\left\{1,2,...,n\right\}$. Each of them has a maximum. Deduce that the average maximum of an r-element subset of $\left\{1,2,...,n\right\}$ is precisely $\frac{r}{r+1}(n+1)$  I don't know how to deduce this. Please, help me.

A subset of $\{1, 2, 3, \dots, 20\}$ containing 10 elements is chosen at random. The largest element of this subset is noted. Find the expected value of the largest element.  I tried to solve this problem by finding the probability of each element being the largest one, but I got confused and would like some help. :)


I thought that if I write  for x = cell_array     ... end   then the loop will run over the elements of cell_array, but in the following case it doesn't:  >> tags  tags =       'dset3'     'dset4'     'cpl1'  >> class(tags)  ans =  cell  >> for t = tags      tmp = t{:}  %No semicolon: i.e. print it.    end  tmp =  dset3   So it only works for the first element.  What's the problem?

Is there a foreach structure in MATLAB?  If so, what happens if the underlying data changes (i.e. if objects are added to the set)?


I am getting this Null pointer expression error on this line (77th line): holder.status.setText(studentItems.get(position).getStatus(studentItems.get(position).getSid(), calender.getDate())); This is the function : public String getStatus(long sid, String date) {         return status;     }  This is the error: java.lang.NullPointerException: Attempt to invoke virtual method    'java.lang.String com.ddm.pix.MyCalender.getDate()' on a null object reference        at com.ddm.pix.StudentAdapter.onBindViewHolder(StudentAdapter.java:77)        at com.ddm.pix.StudentAdapter.onBindViewHolder(StudentAdapter.java:18)  And why is this line getting a error(18th line): public class StudentAdapter extends RecyclerView.Adapter<StudentAdapter.StudentViewHolder>  And getDate() function:  String getDate() {          return String.valueOf(DateFormat.format("dd.mm.yyyy", calendar));     }

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?


How to make short circuit in where clause, e.g:   select 1 where 1=2 AND 1/0=0   In the above example 1/0=0 condition should not be evaluate as the first condition is false.

Let's examine these two statements:  IF (CONDITION 1) OR (CONDITION 2) ...  IF (CONDITION 3) AND (CONDITION 4) ...   If CONDITION 1 is TRUE, will CONDITION 2 be checked? If CONDITION 3 is FALSE, will CONDITION 4 be checked?  What about conditions on WHERE: does the SQL Server engine optimize all conditions in a WHERE clause? Should programmers place conditions in the right order to be sure that the SQL Server optimizer resolves it in the right manner?     ADDED:  Thank to Jack for link, surprise from t-sql code:  IF  1/0 = 1 OR 1 = 1       SELECT 'True' AS result ELSE       SELECT 'False' AS result   IF  1/0 = 1 AND 1 = 0       SELECT 'True' AS result ELSE       SELECT 'False' AS result   There is not raise a Divide by zero exception in this case.  CONCLUSION:  If C++/C#/VB has short-circuiting why can't SQL Server have it?     To truly answer this let's take a look at how both work with   conditions. C++/C#/VB all have short circuiting defined in the   language specifications to speed up code execution. Why bother   evaluating  N OR conditions when the first one is already true or M   AND conditions when the first one is already false.      We as developers have to be aware that SQL Server works differently.   It is a cost based system. To get the optimal execution plan for our   query the query processor has to evaluate every where condition and   assign it a cost. These costs are then evaluated as a whole to form a   threshold that must be lower than the defined threshold SQL Server has   for a good plan. If the cost is lower than the defined threshold the   plan is used, if not the whole process is repeated again with a   different mix of condition costs. Cost here is either a scan or a seek   or a merge join or a hash join etc... Because of this the   short-circuiting as is available in C++/C#/VB simply isn't possible.   You might think that forcing use of index on a column counts as short   circuiting but it doesn't. It only forces the use of that index and   with that shortens the list of possible execution plans. The system is   still cost based.      As a developer you must be aware that SQL Server does not do   short-circuiting like it is done in other programming languages and   there's nothing you can do to force it to.


I know that  to keep the number of child records in Master-Detail relationships (MDR) below 10.000 records.  In one situation I am heavily relying on Sharing being inherited in Master-Detail relationships so I plan to convert a Lookup with 100.000 child records to a MDR.  What will happen? Is the 10K a hard limit or what problems will occur?

Typically, each record in Salesforce will be 2kb large: .   However, let's say in an extreme example, the Opportunity object is related to 40 custom objects, each which has 100,000 records. The page would load much slower, especially in an older browser version.   1) Is there a 'rule of thumb' as to what the upper limit of how many related records an object should have?   2) Also, , there's an indication that there's some sort of tier-tuning per org based on the volume of data it has. Is that correct? And if so, are the volume ranges and respective tier-tuning capacity available?


So, I've been curious about this (since taking a class dealing with filming and editing I've been taking more notice of good/bad shots and just overall more curious about film techniques) when two or more people in a show or something are talking, how do they film that?   I've tried to piece it together myself. My idea is that there is only one camera and the two characters go through the whole conversation while the camera is only showing one person and the back of one person, then the camera switches places and does the same with the other character.   Then from there, the audio would be edited in from the character who is not facing the camera. That would explain why sometimes the characters actions don't always match up, right?   Example one: I was watching a show and three ladies were having a conversation. Lady #1 said her line and lifted her wine glass to her lips. The camera then pointed to the two other ladies but lady #1 had already put her wine glass down, so that means it was filmed more than once right?   And here's also an example of them editing in the audio. I was watching another show and there were two characters talking. The camera was positioned so you could mainly see character #1s reaction while character #2 talked.   This wasn't the exact scene that I was Referring to but it's similar. The girl is character 1 and the boy is #2. In the scene, the camera was just like this, except the girl was just listening to the boy talk. The thing is, his mouth was moving but was not syncing up to what he was saying. So what's up with that?    If I confused you I'm sorry, I tried to word this as best as I could. If your understand me it'd be great to hear back from someone before I go crazy lol

I was always wondering how dialog between two people is filmed. Suppose there are two people talking. The screen is switching between faces of the characters while they talk. How it is done in reality? Are there two cameras filming both faces simultaneously and the actors just talking as usual? Or is the camera filming each actor separately while they say their part of text?


Configuration: report document class, Times New Roman text @12pt with footnote number and text @10pt.    Problem: My institution requires a Times New Roman size 12pt based on Word's, but Times New Roman 12pt in Latex is smaller by about 2pt, and the same goes for footnote number and text size.    Question: How can I increase these proportionately by 2pt or just about? I tried some global packages but they modified my line and paragraph spacing and the result actually made it worse. Looked at several threads but could not find a practical solution.

Warning  If you're looking for advice how to make your document look like it's been written in Word, this is most likely not the question you're looking for. This question is mostly of theoretical nature, as it results in tiny differences, which will most likely not be noticed by someone who doesn't allow the use of LaTeX.  Questions that might be more helpful for this matter are:           Question  I learned that MS Word uses a slightly different version of the unit "point" (pt) than TeX does:     The 12 point of Word will be PostScript point, which in TeX would be called 12bp. A TeX pt is slightly smaller: it's 1/72.27 inch, while a bp/PostScript point is 1/72 inch. See also    ( in )  I'm writing a paper that would usually be expected to be "typeset" in MS Word, thus I want to use the same font size as Word would.  How do I set a document e.g. in the "12pt" font size that MS Word would use?  In case it matters, I'm using the article document class, Latin Modern (lmodern) as a font with the T1 font encoding and compile with pdfLaTeX, but input on different set-ups is more than welcome.


I am writing a script for windows to install a selenium service that also sets the PATH for the chrome and ie drivers, but just setting them every time the script runs (if anything is updated) will eventually run into appending the same variables to the end over and over. I tried this:   setx IEDRIVER "%~dp0..\ie" /m setx CHROMEDRIVER "%~dp0..\chrome" /m if not x%PATH:IEDRIVER=%==x%PATH% setx path "%PATH%IEDRIVER;" /m if not x%PATH:CHROMEDRIVER=%==x%PATH% setx path "%PATH%CHROMEDRIVER;" /m   but I get the error:  C:\Windows was unexpected at this time.   The end goal is to check to see if a variable is in the path, if it isn't set that variable.

How does one check if a directory is already present in the PATH environment variable? Here's a start. All I've managed to do with the code below, though, is echo the first directory in %PATH%. Since this is a FOR loop you'd think it would enumerate all the directories in %PATH%, but it only gets the first one.   Is there a better way of doing this? Something like find or findstr operating on the %PATH% variable? I'd just like to check if a directory exists in the list of directories in %PATH%, to avoid adding something that might already be there.  FOR /F "delims=;" %%P IN ("%PATH%") DO (     @ECHO %%~P )


I have only ever played Pathfinder and the way it works in that system is you would get extra spell slots based on how much intelligence you had. So in , it shows how many more spells per day you get based upon how much more intelligence you have.  Do you get any extra spells as a spellcaster in D&D 5th edition?   This is all I could find in the D&D 5th Edition players handbook:     You prepare the list of wizard spells that are available for you to cast. To do so, choose a number of wizard spells from your spellbook equal to your Intelligence modifier + your wizard level (minimum of one spell). The spells must be of a level for which you have spell slots.   Nothing says anything about bonus spells slots. I just want to confirm that you do not get bonus spells in 5th edition D&D, right? Because if the chart on page 113 of the PHB says to only choose two 1st level spells to prepare as a 1st-level wizard, what do I follow?

In previous versions, spell casters were given bonuses to available spells based on their casting ability score. I don't remember exact stats but to make an example, A wizard would be able to memorize extra spells:  Int 14 = 1 extra lvl 1 Int 15 = 2 extra LVL 1 Int 16 = 2 extra lvl 1 and 1 extra lvl 2 Int 17 = 2 extra lvl 1, 2 extra lvl 2 and is required for casting lvl 8 spells Int 18 = 2 extra lvl 1, 2 extra lvl 2, 1 extra lvl 3, and is required for casting lvl 9 spells.  I can't seem to find mention of this bonus in D&D 5th Edition. Does it apply to prepared spell limit, spell slots, or has it been obsoleted?  Note: I also can't seem to find mention of a prepared spell limit, or feats.


I am having trouble opening an .e00 file in QGIS. (QGIS keeps locking up, and I have to "force-quit".) The file is political administrative boundaries in China.  Would it be feasible to convert the .e00 file to a CSV and import that CSV? 'Cause the .e00 file, when I open it with a text editor, looks like a spreadsheet document.  I am using QGIS 2.12 Lyon on a Mac running OS X 10.10.5.  Edit: I do not see how my question is a duplicate of "How to read Arc/Info e00 vector files (no binaries) with Python?" [I'll call that "Question A".]  First, Question A says "I can easily read e00 files with QGIS..." but in my case, I cannot easily read e00 files. I have only partial success displaying their data.  Second, I am asking whether I can turn my e00 file into a CSV file and then use the CSV file in QGIS. Question A makes no mention of CSV files. Third, I do not mention Python. I have no idea how to use Python.  I have read Question A and the answers given, and I do not understand what they are talking about. For example, when I run "ogrinfo --formats" I get "-bash: ogrinfo: command not found".

I can easily read e00 files with QGIS and it seems as if in older versions of ogr there was driver support for the arc/info e00 file format. Nowadays that seems to be deprecated, as running ogrinfo --formats doesn't list arc/info.  I also found this useful , a general description of the file format. Based on that information I would be able to write my own program to put all the pieces together. But hey, this must have been done before, right?  Can somebody point me into the right direction?


I'm struggling to prove symmetry for the railway metric.  Let $d:\mathbb{R}^{2}\times\mathbb{R}^{2}\rightarrow[0,\infty)$  $$d(x,y)=\begin{cases}\|x-y||&\text{ if }x,y,0\text{ are collinear}.\\\|x−0||+\|0-y||&\text{ otherwise}.\end{cases}$$  I have managed to show $d(x,y)=\|x-y\|=\|x-x\|=\|0\|=0.$

I am trying to work just one case of showing that the French railways metric defined by a metric space $(\mathbb{R}^2,d)$ is actually a metric:  $$d(x,y) = \begin{cases} \|x-y\|, & \text{if $x,y,0$ are collinear;} \\ \|x\| +\|y\|, & \text{otherwise} \end{cases}$$  I am trying to show the case that if $x=y$, then $d(x,y)=0$. I have been able to show that if $x=y$, then $\|x-y\|=0$, but am having a hard time showing that if $x=y$, then  $\|x\| +\|y\|=0$. Thank you!


There is a user who firstly asked a question from its real account. But, after no getting the answer, he/she created a new account and asked the same question again. I tried flagging the post but nothing happened. I don't think meta is not a good place to report these cases everytime. So, where should I report these cases.  Original account:   Duplicate account:   Original question:   Duplicate question:

There's a user, , who has a rather checkered history of creating alternate accounts, whether for  or .  He's now created a new account, .  As always, the account looks to be very clearly his, down to the same avatar, same website, etc.  In this case, however, he hasn't really done anything wrong yet on the surface, that I can see--there's no sock-puppetry that seems to be going on between the pair, and this time, it wasn't to skirt a suspension.  It mostly looks like the account was created to escape a very negative history with the previous account.  When, exactly, is it appropriate to report multiple accounts?  Should a person with a history of multiple account abuse be reported simply for having multiple accounts, or is there some further requirement of a new bad act that should occur first?


I'm flying out of Charlotte, NC on June 3rd with my 13 yr old beagle in cargo.  Will the temperature in cargo be 85 degrees or higher?  If so, I've been told they won't fly her!

I want to take some chocolates to offer in my luggage. Chocolates are a bit sensitive to heat, though. What is the average temperature inside a cargo hold? 'Average by' itself can be misleading. What is the max temperature there?  I don't know much about airplane mechanics but I assume they have some cooling systems like any other engine. Such systems, depending on where they are placed, might influence temperature in the cargo hold. I also fear temperatures in the ground while exterior temperatures are higher, and luggage is being put inside. What are max temperatures near the airplane in such situation?


I own a Lenovo T430 laptop. In 2017, I installed Windows 10 using my original Windows 7 product key. Unfortunately, I cannot find that product key anymore. I need to re-install windows 10. Will it be automatically activated after the installation, if I skip the step of asking the product key during the installation?   In my opinion, I believe that my laptop will have a digital entitlement stored on the Microsoft Activation Servers and this will not be a problem. Is that true?  If not, please suggest me a solution or a workaround.

I've been using Windows 10 for a couple of month now (joined the Insider Preview).  Now my hard drive started ticking so I've bought a new SSD and I want to move the windows installation to the new hard drive, which has been connected to the computer (unpartitioned). I don't mind and I even prefer reinstalling it over again.   Since I have the free version of Windows 10 pro, can I still reinstall it anew? Does the windows 10 installation offer disk management and partition like the older Windows installations used to? How should I reinstall Winodws 10 x64 the easiest but still remain on free mode?


To reduce the heat lost during transmission of electricity, we say we increase the voltage of transmission, taking the formula $I^2R$ in consideration. Couldn't I consider $V^2/R$? If I consider the second form, increasing voltage will increase the power dissipated. No?

If we want to transmit electic current for a long distance, we must minimize a heat that releases because of the resistanse. We cannot make a cable wide because it is expensive and it will be massive. So, we must decrease a current because $Q = I^2R\Delta t$. A power that we want to transmit is constant, $P = UI$, so we must increase the voltage. Nevertheless, $Q = \frac{U^2}{R}\Delta t$, so if we increase the voltage, the heat will increase too. And for addition, $U = IR$, so if we decrease the current, the voltage will decrease too.  Could you, explaine in details where I have a mistake.  P.S. sorry for my English, I am not a native speaker.


How does Minecraft generate it's texture (ex. which block is grass and which one is stone)?

I want to generate a completely unique world with biomes (like what Minecraft and similar games do). I don't understand how they generate these entire worlds from a single "seed" number. Can someone provide a basic overview of the technique?


I have to find the Jordan basis of the following matrix:  $$A=\begin{pmatrix} 2&0&-1&1\\ 1&1&-1&1\\ 1&-3&2&-1\\ 0&-3&2&-1\\  \end{pmatrix} $$  I computed the characteristic polinomial $P_A(t)=(t-1)^4$  I'll just skip the calculations and state what I found, I got (${\lambda_1=1}$): $$\dim(V_{\lambda_1})=\dim(\ker(A-\lambda_1I))=2$$$$V_{\lambda_1}^2=\ker((A-\lambda_1I)^2)=Span\left(\begin{pmatrix} 0\\ 1\\ 0\\ 0\\  \end{pmatrix}\begin{pmatrix} 1\\ 0\\ 1\\ 0\\  \end{pmatrix}\begin{pmatrix} -1\\ 0\\ 0\\ 1\\  \end{pmatrix}\right)$$$$V_{\lambda_1}^3=\mathbb{R^4}$$ Therefore for my Jordan basis: $$v_3\in V_{\lambda_1}^3/V_{\lambda_1}^2$$ So I choose $v_3=\begin{pmatrix} 0\\ 0\\ 0\\ 1\\  \end{pmatrix} $  Then I calculated $v_2$ as $v_2=(A-\lambda_1I)v_3$ and $v_1$ as $v_1=(A-\lambda_1I)^2v_3$.  I got $$v_2=\begin{pmatrix} 1\\ 1\\ -1\\ -2\\  \end{pmatrix},\;\;v_1=\begin{pmatrix} 0\\ 0\\ -1\\ -1\\  \end{pmatrix}$$ Indeed these 3 vectors are fine. (I checked by computing) When I have to choose the last vector $v_4$ (i.e. the one associated with the Jordan block of order 1) I'm not sure how to procede, I read on some notes that I should choose $v_4 \in V_{\lambda_1}^3/span(v_1,v_2,v_3)$ but that doesn't really seam to work...  The method presented in my textbook is somewhat unclear and I couldn't find anywhere a good explaination on a canonical method to follow when looking for the Jordan Basis of a matrix...

I'm facing a problem finding a Jordan basis for this ($4 \times 4$) matrix: $$\left(\begin{matrix}3&-1&1&7\\9&-3&-7&-1\\0&0&4&-8\\0&0&2&-4\end{matrix}\right)$$  I know that the characteristic polynomial is $\lambda^4=0$ and it's minimal polynomial is: $x^2$. This means that $(A-0I)^2=0$. Also the Jordan form for this matrix is $$\left(\begin{matrix}0&1&0&0\\0&0&1&0\\0&0&0&1\\0&0&0&0\end{matrix}\right)$$ But I'm facing problems in the general procedure to compute the basis for such a matrix?


In ArcGIS 10.5, I am building a model that should convert a field of coded values to another code. This seems like it should be a simple if/then statement but I am not getting it. To simplify the process, I populated the target field with the source field's values and then intend on using python to transpose the values. It should be considered a string, but the values are numerical.   In the "Calculate Field" code block:  def reclass: if TP_Condi = 3:      return 1 elif TP_Condi = 2:      return 8 elif TP_Condi = 1:      return 3 else:      return "error"

In ArcGIS 10.5, I am building a model that should convert a field of coded values to another code. This seems like it should be a simple if/then statement but I am not getting it. To simplify the process, I populated the target field with the source field's values and then intend on using python to transpose the values. It should be considered a string, but the values are numerical. The field I am trying to edit is "TP_Condi"   In the "Calculate Field" code block:  def reclass:   if TP_Condi = 3:          return 1     elif TP_Condi = 2:           return 8   elif TP_Condi = 1:          return 3   else:          return "error"      This is the code I was seeking:


I tried all to make the quotation marks work but still failed!  I tried ``word'' , I also tried csquotes but still it is not working and instead of proper quotation marks the result is "word".  It works when I use the article document class or other popular document classes.  But when I am working with the document class file for writing thesis( ), quotation marks do not work.  Is it something related to quotation marks in cls files that I have to add to the cls file I am using or problem is something else?

I've just started using font Palatino for my documents, and I've realized the opening quotes are all rendered as closing quotes. As per the question  I use ``hello'' to quote, but somehow Palatino is always showing both as closed. If I uncomment \usepackage[sc]{mathpazo} then they are rendered correctly. How can I fix this?


There is a minor inconsistency in the newest tab, between the mobile and the full site.   In the mobile site it shows the person that did the last edit (or who posted the last answer) - just like in the "active" tab    but in the full site is shows the OP.    This seems like an (admittedly really minor) bug to me...

If you use the mobile mode, then sort questions by newest, the usernames displayed won't be the ones of the author, they will be the one who made the last activity (just like when we sort by active in the normal mode).    I believe this is a bug, it wouldn't make much sense why it behaves different from the non-mobile mode.  Note: I didn't check with other kind of sorting, but maybe it happens with others too.


Many questions here ask for how to get a certain MTP enabled device (a phone, tablet or media player) working, assuming that the device is somehow supported by current FOSS software. But what to do if it is not?  Problem: The device is not detected by mtp-detect  Connecting the MTP capable device to the computer and running mtp-detect from the  package in terminal returns:  No raw devices found.

Since Ubuntu 13.04 storage access to external devices via MTP is supposed to work out of the box via a GVFS-MTP module.      While this question is about the Galaxy Nexus, other Android devices as well as Windows Phones and MTP enabled media players are also supported.      For troubleshooting see .     I am having quite a bit of problems getting file-transfers working over MTP with the Galaxy Nexus. I am using Kubuntu 11.10 64-bit, and this is what I have done and the results I get:   Added rule for device in /etc/udev/rules.d/51-android.rules. The rule is the following and works for adb:  SUBSYSTEMS=="usb", ATTRS{idVendor}=="04e8", ATTRS{idProduct}=="6860", MODE="0666", OWNER="leob" #Galaxy Nexus  Restarted udev (and computer just to make sure).   Adb works, and all methods for reading from the device via MTP seems to work (I have tried mounting with mtpfs, gmtp and using the mtp-tools package directly). When I try to write to the device however, nothing I have tried works.  As an example, running mtp-newfolder test_dir 0 0 gives the following output:  libmtp version: 1.1.0 Device 0 (VID=04e8 and PID=6860) is a Samsung GT-P7510/Galaxy Tab 10.1. Folder creation failed. ERROR: Could not close session!   If I run mtp-folders after a failed mtp-newfolder without re-plugging the device, I get the following output:  Attempting to connect device(s) Device 0 (VID=04e8 and PID=6860) is a Samsung GT-P7510/Galaxy Tab 10.1. PTP_ERROR_IO: failed to open session, trying again after resetting USB interface LIBMTP libusb: Attempt to reset device mtp-folders: Successfully connected Friendly name: (NULL) Error 1: Get Storage information failed. Error 2: PTP Layer error 02fe: get_all_metadata_fast(): could not get proplist of all    objects. Error 2: (Look this up in ptp.h for an explanation.) Error 2: PTP Layer error 02fe: get_handles_recursively(): could not get object handles. Error 2: (Look this up in ptp.h for an explanation.) LIBMTP_Get_Storage() : Resource temporarily unavailable OK.   Accompanied by the following in dmesg:  [ 1000.912082] usb 2-4: reset high speed USB device number 7 using ehci_hcd [ 1001.045877] usb 2-4: usbfs: process 3166 (mtp-folders) did not claim interface 0 before use   Does anyone have any idea about what to do?  EDIT:  I also tried the PTP mode. Again, reading works fine, but I cannot write anything to the device.


I recently bought the Panasonic GH4, which is weather-sealed. I also got the 14-140mm lens that Panasonic makes for it (I believe it's the first version and they have a new version -  mine is .  So I know I'm fine to use the GH4 out in some rain, or that kind of thing - I'm not sure exactly HOW much weather it'll take, but it'll obviously stand up to some - but I have no clue how it'd stand up to weather. Obviously it has electronics for the focusing/OIS/etc in it, and it doesn't specifically say it's weather protected, although someone mentioned in an Amazon review that they dropped it in snow and left it overnight and it was fine - but do I trust them??  The electronics are what scare me. I plan to use some of my older, fully manual lenses (or maybe some new Rokinon ones) and mostly use them in bad weather, which I think is ok (?), but does anyone know about newer lenses like the one mentioned?

What is the structural and mechanical differences between a weather sealed body and a non weather sealed body? Is weather sealing still effective if the lens isn't weather sealed?


Suppose that we have $f_{1},\cdots, f_{n}$ holomorphic in a connected open set $D$. For $$f(z):=|f_{1}(z)|+|f_{2}(z)|+\cdot+|f_{n}(z)|\ \ \text{for}\ \ z\in D.$$ I want to show that $f(z)$ cannot achieve a strict local maximum inside $D$.  I know that this must have something to do with the maximum modulus principle, especially we have some connected open set, this will enable us to directly conclude that a function $g(z)$ is constant all over $D$ if it is holomorphic in $D$ and $|g|$ achieves a local maximum at $z_{0}\in D$. However, I cannot connect this theorem to $f(z)$ because even thought $f_{k}(z)$'s are holomorphic, the summation of moduli of them may not be holomorphic. I know a way to show that  Let $D$ be a disc with radius $R$ and center $z_{0}$. Suppose $f_{k}(z)$'s are holomorphic on $D$ and continuous on $\partial D$ such that $f(z_{0})\geq z$ for all $z\in D\cup C$, then $f$ is constant in $D\cup C$.  I can prove this claim using Cauchy's Integral formula, but it is long. This lemma can certainly conclude the proof quickly, but I realized that I did not really use the "connectedness" of $D$.  Is there any way for me to drive a shorter proof using maximum modulus principle? Thank you!  Edit 1: The post is duplicated, but I'd still like to post a relatively complete proof. Thanks to Conrad, the following is a relatively complete proof: Suppose $\omega$ is the local maximum of $f(z):=\sum_{k=1}^{n}|f_{k}(z)|$. Note that as $f_{k}(\omega)$ is a complex number, unless it is zero, we can represent (uniquely) as $$f_{k}(\omega)=|f_{k}(\omega)|e^{it_{k}},\ \ t_{k}\in [0,2\pi).$$ Take $\alpha_{k}:=e^{-itk}$, and if $f_{k}(\omega)=0$ for some $k$, we tae $\alpha_{k}:=1$. Then, we have $$f_{k}(\omega)=\alpha_{k}^{-1}|f_{k}(\omega)|\ \text{with}\ |\alpha_{k}|=1.$$ Now, define $g(z):=\sum_{k=1}^{n}\alpha_{k}f_{k}(z).$ Then, we have \begin{align*} |g(z)|\leq \sum_{k=1}^{n}|\alpha_{k}||f_{k}(z)|=\sum_{k=1}^{n}|f_{k}(z)|&=f(z)\\ &\leq \sum_{k=1}^{n}|f_{k}(\omega)|=f(\omega)\\ &=\sum_{k=1}^{n}f_{k}(\omega)\alpha_{k}=g(\omega)\leq|g(\omega)|\ \ \ (*). \end{align*} Hence, $\omega$ is also the point at which $|g|$ achieves local max. As $g$ is holomorphic and $D$ is connected open, by the global maximum modulus principle, we conclude that $g(z)=C$ for some constant $C$ and for all $z\in D.$ But then, $(*)$ implies that $$|C|\leq C\leq |C|\implies C=|C|\implies C\geq 0.$$ So we have $g(z)=g(\omega)\geq 0$. But then (*) implies that $$g(\omega)=g(z)=|g(z)|\leq f(z)\leq f(\omega)\leq g(\omega),$$ and thus we must have $$g(\omega)=g(z)=f(z)=f(\omega)=C\geq 0\ \ \text{for all}\ \ z\in D,$$ and thus the local maximum of $f$ cannot be strict.  I really appreciate the patient and inspiring help from Conrad.

Let $f_1,f_2,\ldots,f_n $ be  analytic complex functions in domain $D$. and $f = \sum_{k=1}^n|f_k|$ is not constant.  Can I show the  maximum of $f$ only appears on boundary of $D\,$?


I just developed a logistic regression model predicting customer churn (i.e how likely is a customer to leave us in the future?)  To understand the impact of my independent variables I calculated Odds ratio using the following function.   exp(trainingmodel$coefficients)  Where trainingmodel is the name of my model.  And I get the following results:  AIRTIME  9.789127e-01  Site.Report.By.Vehicle1 1.241823e+00   Both AIRTIME and Site Report are a feature of product we offer. In my dataset, AIRTIME is a continuous variable whereas Site.Report.By.Vehicle1 is a categorical variable with just two levels, ie. someone using the Site Report or not?  Can someone please help me to understand how to interpret the above number for AIRTIME and Site Report?

I have run the following logistic regression:  glm(formula = DecisionasReceiver ~ L1 + L2 + L3,    family = binomial("logit"), data = lue)   where L1 L2 and L3 code for differences in condition of no.GREEN. L1: 1,-1,0,0 : is there a difference in DecisionasReceiver as no.GREEN changes from 1 to 2?  L2: 0,1,-1,0: is there a difference in DecisionasReceiver as no.GREEN changes from 2 to 3?  L2: 0,0,1,-1: is there a difference in DecisionasReceiver as no.GREEN changes from 3 to 4?  And I'm running this regression both for the cases where MessageReceived is BLUE and for MessageReceived RED.   I have the following output:     Coefficients:       Estimate Std. Error z value Pr(>|z|)     (Intercept)  -0.9535     0.3659  -2.606  0.00916 **  L1            2.2753     0.5406   4.209 2.56e-05 *** L2            3.1234     0.7318   4.268 1.97e-05 *** L3            1.9369     0.8134   2.381  0.01726 *     Looking at my graph it seems strange that the coefficients are positive and that the intercept is -0.953. How exactly should I interpret these results in the light of the graph?


How many different groups are there in order 8? And how do I know which groups they are? I mean, is there anyone can teach me to calculate them? I want a proof, thank you!  They are $C_8$, $D_4$, $Q_8$, $C_{4h}=C_4 \times V_2$, $D_{2h}=D_2 \times V_2$

It's often said that there are only two nonabelian groups of order 8 up to isomorphism, one is the quaternion group, the other given by the relations $a^4=1$, $b^2=1$ and $bab^{-1}=a^3$.   I've never understood why these are the only two. Is there a reference or proof walkthrough on how to show any nonabelian group of order 8 is isomorphic to one of these?


The original message was:     Right now, I think that this chatroom should be for deciding what we're going to do in the next event, if it ever happens.   And yet, the bold text disappeared. Why?

Previous question:    That was when my buttons died.  On other days, my text dies.    And some times it's just italics.    Now, I like blaming @skiwi for this, and he's often nearby when it happens.  But today, he's not here, and it happened again.    I'm running Windows 8 and using Chrome 40.0.2214.94 m.  Refreshing and such does not fix the issue.  Inspect element -> console -> error log:  http://chat.stackexchange.com/chats/8595/messages/new Failed to load resource: the server responded with a status of 409 (Conflict) http://i.stack.imgur.com/2ZJdJ.png?s=128&g=1&g&s=16 Failed to load resource: the server responded with a status of 502 (Bad Gateway) http://i.stack.imgur.com/boUZp.jpg?g&s=16 Failed to load resource: the server responded with a status of 502 (Bad Gateway) http://i.stack.imgur.com/U8P3C.jpg?s=128&g=1&g&s=32 Failed to load resource: the server responded with a status of 502 (Bad Gateway) http://i.stack.imgur.com/boUZp.jpg?g&s=16 Failed to load resource: the server responded with a status of 504 (Gateway Time-out) http://chat.stackexchange.com/messages/19891816 Failed to load resource: the server responded with a status of 409 (Conflict)   What's going on here?  I should note, I can view italics by selecting, then alt-tabbing:    So it reeks of a client-side issue. What's hiding the text from me?  EDIT:  30 april 2015 it happened again =/


I'm applying for masters. Will those reading my applications actually bother looking up the people that wrote my references?   I'm considering whether I should ask prestigious academics (who don't know me well) write my references vs not-so-prestigious ones (who know me). Obviously if they wont google the names, I should go with the latter.

I approached my internship advisor for an LOR while applying to Masters. She said she would not be able to provide a strong one but a good one based on an internship that lasted for two months. I approached her because she holds a PhD from a good university in the USA and she's published papers in top-tier conferences and journals. Will it adversely affect my application? Will it hold as much weight as a strong one because it's she who's recommending it?


I encountered a couple of sentences, mostly in American movies, that I wondered why they have something I call ' Double negatives', for example:  Don't go no further (why not Don't go further) We can't grow no crops without no water I don't see no friends (why not I don't see any friends / I see no friends)  What's the structure of these sentences, are these considered informal? Are there any other correct alternatives to them?

In my native language, double negations "cancel out". I have been trying to learn English using movies and such things, but double negation confuses me. I see instances when double negation cancels out, and some when they do not.  For example, "I haven't got no money" is interpreted as "I have no money." "There wasn't anyone who didn't enjoy the party" is interpreted as "Everyone enjoyed the party."  Is this context dependent? If so, how does one decide which interpretation is correct?


I would like to be able to compare 2 models as is often done as follows:  modelA <- lm(Ys ~ X1 + X2 + X3) modelB <- lm(Ys ~ X1 + X2) anova(modelA, modelB)   but instead of adding or removing a co-variate- my first model is a fixed effects model with a single time point per subject, and my second model is a mixed effects model with several time points per subject and grouped by subjectID:  modelA <- lm(Ys ~ X1 + X2 + X3) #e.g. 5 observations/subjects  modelB <- lme(Ys ~ X1 + X2 + X3, random= ~ 1 | subjectID)  #e.g. same 5 subjects with 3 time points each= 15 observations   since chi-square with anova fails in this scenario, how should I compare them. Is there a specific package in R I should use? An F-test requires knowing what the d.f. are for a mixed model, which I am unclear on how to calculate.  Thanks for your help!

Given three variables, y and x, which are positive continuous, and z, which is categorical, I have two candidate models given by:  fit.me <- lmer( y ~ 1 + x + ( 1 + x | factor(z) ) )   and  fit.fe <- lm( y ~ 1 + x )   I hope to compare these models to determine which model is more appropriate. It seems to me that in some sense fit.fe is nested within fit.me. Typically, when this general scenario holds, a chi-squared test can be performed. In R, we can perform this test with the following command,  anova(fit.fe,fit.me)   When both models contain random-effects (generated by lmer from the lme4 package), the anova() command works fine. Owing to boundary parameters, it is normally advisable to test the resulting Chi-Square statistic via simulation, nonetheless, we can still use the statistic in the simulation procedure.  When both models contain only fixed-effects, this approach---and, the associated anova() command---work fine.  However, when one model contains random effects and the reduced model contains only fixed-effects, as in the above scenario, the anova() command doesn't work.  More specifically, I get the following error:   > anova(fit.fe, fit.me)  Error: $ operator not defined for this S4 class   Is there anything wrong with using the Chi-Square approach from above (with simulation)? Or is this simply a problem of anova() not knowing how to deal with linear models generated by different functions?  In other words, would it be appropriate to manually generate the Chi-Square statistic derived from the models? If so, what are the appropriate degrees of freedom for comparing these models? By my reckoning:  $$ F = \frac{\left((SSE_{reduced}-SSE_{full})/(p-k)\right)}{\left((SSE_{full})/(n-p-1)\right)} \sim F_{p-k,n-p-1} $$  We are estimating two parameters in the fixed effects model (slope and intercept) and two more parameters (variance parameters for the random slope and random intercept) in the mixed-effects model. Typically, the intercept parameter isn't counted in the degrees of freedom computation, so that implies that $k=1$ and $p=k+2=3$; having said that I'm not sure if the variance parameters for the random-effects parameters should be included in the degrees of freedom computation; the variance estimates for fixed-effect parameters are not considered, but I believe that to be because the parameter estimates for fixed effects are assumed to be unknown constants whilst they are considered to be unknowable random variables for mixed effects. I would appreciate some assistance on this issue.  Finally, does anybody have a more appropriate (R-based) solution to comparing these models?


I have a 2009-vintage  with a 1280x1024 60 Hz monitor. The onboard video seems to work fine but the video from the  is a resolution that the monitor will not accept.  How do I change the resolution in Ubuntu?

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


Im trying to create the 74XX series IC's from scratch, using just transistors, resistors and diodes. I intend to chain them together and create some logic systems. Right now i'm trying to create a basic NAND gate but i can't find any transistors with at least two emitters. Why? Can i just take two transistors and solder together first the bases and then the collectors? Or maybe create it from diodes?  What i want to know is where can i obtain such a transistor or how to make one. I know how it works and where its used.  Here is an image of a NAND TTL gate:

I sometimes come across with BJT symbols from which multiple lines come out of emitter or collector. Are such BJTs different kind of devices? What does it mean in solid-state level?


Show the following for all positive integers using proof by induction:  $$\sum_{k=1}^{n} k^3 = \bigg( \sum_{k=1}^{n}k\bigg)^2$$  Base case (n = 1) passes: $1^3 = 1^2$  We assume the following: $$\sum_{k=1}^{p} k^3 = \bigg( \sum_{k=1}^{p}k\bigg)^2$$  This gives us:  $$\sum_{k=1}^{p+1} k^3 = \bigg( \sum_{k=1}^{p}k\bigg)^2 + (p+1)^3 =  \bigg( \sum_{k=1}^{p+1}k\bigg)^2$$  This is as far as I have gotten. I have no Idea as to how I expand it so it becomes obvious that they are in fact equal.

How can I prove that     $$1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$$    for all $n \in \mathbb{N}$? I am looking for a proof using mathematical induction.  Thanks


If N is a perfect square, then we know that N has an odd number of distinct factors (because the square root gets counted twice).   However, can we prove that if N is a perfect square, then it will always have an odd number of odd factors and even number of even factors? If N is an odd perfect square, then each factor must be odd and therefore N has an odd number of odd factors and no even factors. However, I can't prove the same for even squares, since factors could be either odd or even, as long as one of the numbers in each pair is even..

I believe I have the solution to this problem but post it anyway to get feedback and alternate solutions/angles for it.  For all $n \in \mathrm {Z_+}$ prove $n$ is a perfect square if and only if $n$ has odd # of positive divisors. Thought to use induction but the perfect squares don't increase by 1.    $\Rightarrow$: If $n$ is a perfect square it must consist of 1+ prime factors each to an even power.  If $n$ consists of 1+ prime factors each to an even power it must have an odd # of positive divisors.  $\Leftarrow$: If $n$ has an odd number of positive divisors it must consist of 1+ prime factors each to an even power.  If $n$ consists of 1+ prime factors each to an even power it must be a perfect square.  Thanks.


Prove that $\sin \frac{{2\pi }}{7} + \sin \frac{{4\pi }}{7} + \sin  \frac{{8\pi }}{7} = \frac{{\sqrt 7 }}{2}$.   I have tried to square both side and got ${\sin ^2}\frac{{2\pi }}{7} + {\sin ^2}\frac{{4\pi }}{7} + {\sin ^2}\frac{{8\pi }}{7} = \frac{7}{4}$. But I cannot proceed further. Any help would be appreciated.

Find the value of $\sin\frac{2\pi}{7}+\sin\frac{4\pi}{7}+\sin\frac{8\pi}{7}$  My approach :   I used $\sin A +\sin B = 2\sin(A+B)/2\times\cos(A-B)/2 $  $\Rightarrow \sin\frac{2\pi}{7}+\sin\frac{4\pi}{7}+\sin\frac{8\pi}{7} = 2\sin(3\pi)/7\times\cos(\pi/7)+\sin(8\pi/7) $  $= 2\sin(3\pi)/7\times\cos(\pi/7)+\sin(\pi + \pi/7) $  $= 2\sin(3\pi)/7\times\cos(\pi/7)-\sin(\pi/7) $  I am not getting any clue how to proceed further or whether it is correct or not. Please help thanks..


I use Ubuntu 16.04 with Bash and I'm ought to enable http2 for a particular website I have on an Nginx environment.    Natively, the utility sed does its text-processing on the first instance in the first relevant line (using g argument would make it to process all instances on the first relevant line), but I desire to do a particular operation on 2 or more lines (all lines actually).  I took a look at man sed and found the -l argument that let's you specify number of lines to work with (if I understood correct), but I desire to work on all lines, without being dependent in particular amount of lines.  The particular case I'm having is that I try to unify these two sed operations into one:  s_a="/etc/nginx/sites-available/" $domain="example.com" sed -i "s/listen 443 ssl default_server;/listen 443 ssl http2 default_server;/" $s_a/$domain.conf sed -i "s/listen [::]:443 ssl default_server;/listen [::]:443 ssl http2 default_server;/" $s_a/$domain.conf   I could unify the two sed operations to something like:  sed -i "s/443 ssl default_server/443 ssl http2 default_server/" $s_a/$domain.conf   I assume that the safest way to make sure I cover all relevant lines in such convenient one line operation is to use some argument but I don't know if this can be done with the -l argument if at all, or I must use regex.

I am trying to replace multiple words in a file by using   sed -i #expression1 #expression2   file  Something  123 item1 Something  456 item2 Something  768 item3 Something  353 item4   Output (Desired)  anything  123 stuff1 anything  456 stuff2 anything  768 stuff3 anything  353 stuff4   Try-outs  I can get the following output by using sed -i two times.   sed -i 's/Some/any/g' file  sed -i 's/item/stuff/g' file   Can I have any possible way of making this as a single in-place command like   sed -i 's/Some/any/g' -i 's/item/stuff/g' file   When I tried the above code it takes s/item/stuff/g as a file and tries working on it.


I'm just trying out the SE app, and while I like a lot of the features, most of the recommend jobs are for Android engineers (something I most certainly am not).  I really like Careers 2.0, but it seems the recommendation engine could use some work.

Within the iOS App, the posts from careers clearly are using some sort of IP database to pick which posts to show in the feed (since sometimes they localize well, others not so much).  It would be far more effective to let people choose to share location information or key those posts off of tags or some other signal and fall back to the algorithm you have at present.  I could easily see this not being a 1.0 feature, but if you are going to post ads why not make use of the platform's capabilities to deliver better results for people that choose to opt in?


When plotting fast oscillating data from a table with pgfplots, an overshoot of the curve was observed (due to interpolation?). If the same data was plotted using Matlab, no overshoot occurred. The same phenomenon was observed when plotting a fast oscillating function, instead of data from a table. Here is the minimum working example, where a chirp signal sin(x^2) is displayed:    \documentclass{article} \usepackage{pgfplots} \begin{document}  \begin{tikzpicture} \begin{axis}[xmin=0,xmax=150,ymin=-1.2,ymax=1.2,width=0.4\textwidth,height=0.3\textwidth]     \addplot[         thick,         mark=none,         domain=0:150,         samples=1000,     ] {sin(x^2)}; \end{axis} \end{tikzpicture}  \end{document}   The figure was compiled using PDFLaTeX, from the MiKTeX distribution. One can note that the curve overshoots 1 in absolute value, starting around the abscissa x=50. How to remove these spurious peaks?

I plot tabular data wherein none of the y-values of the data go above 1.0. In the resulting plot, however, there are a couple of peaks that go beyond 1.0, giving a false impression about those data points:   This is not visible when I plot with marks, but I need to use "no marks" because it is otherwise far too busy (80 points in a small plot).   How can I prevent this?  Update: Per Jake's request, here's a minimal example that shows the described behaviour:  \documentclass{article} \usepackage{pgfplots} \begin{document}     \begin{figure}[ht]         \begin{tikzpicture}             \begin{axis}[no markers, grid=major]                 \addplot coordinates{(0, 0.0000000000)                                      (1, 0.8823529412)                                      (2, 0.8750000000)                                       (3, 1.0000000000)                                       (4, 0.8666666667)                                      (80, 0.0000000000)}[thick];             \end{axis}         \end{tikzpicture}     \end{figure} \end{document}   The problem is less pronounced when I don't make my lines thick, but it is still there (and I want thick lines).


I am running a lasso model to predict a continuous variable, and I have continuous and categorical inputs.  In terms of centering and scaling - is it correct that this should only be applied to continuous variables? Also, in terms of the dummy variables step, can this be ignored for the categorical? It just doesn't make sense when it comes to scoring.  For example, if the training set has a category called Cats, that has levels A-Z, this would create a column for A-Z. But if my scoring set is missing one of these levels then it will fall over. Looking for some guidance.

Say I have a data set with say 5000 rows and about 150 columns (5000 samples, 150 predictors/features) and I'm interested in a applying a ridge or lasso regression. (Let us assume using a logit link function -- if it matters). Again, if it matters, we'll say that some features are highly correlated -- e.g., that more than half of them are actually dummy variable indicators. Let us also say we are more concerned with prediction accuracy than model interpretability (if we wanted a clean interpretation, we would not use a penalized regression!)  Now, the standard recommendation for penalized linear models is to standardize the data (I believe Tibshirani recommends this always. By standardize, I mean center and scale by the mean and standard deviation). However, this will destroy a lot of the structure inherent in the data set. It doesn't make sense to do this I think - since this will lead to what were binary indicators always being present in the model unless Lasso zeroes them out.  Is there a better way to deal with this issue? One could normalize the rows (e.g., Normalizer() in sklearn) which will preserve structure, but in practice this gives me vastly different results.  Should one standardize all inputs? Only non-binary ones? What about ordinal categories (say a column with 1,2,3,... measuring, say, years of education). Normalization or min/max scaling?  Clarification: By standardizing binary inputs, you remove the sparsity in the data set, as you must first subtract the mean. This is what I mean by "destroying the structure".


I'm using  in  and I'm trying t o find out exactly how R squared and adjusted R squared is calculated for panel models in .  I looked at , on which I can , but it did not have any references or further links. The source code is a bit complex for me to deconstruct. Normally the man pages are very good with references or links, but I can't seem to find my way here. Any help would be appreciated. I realize this might be incredibly simply.

Based on my understanding, panel fixed effect model is equivalent to OLS with individual dummies. However, when I ran the two models in R, the $R^2$ from the two models were quite different: 0.8 for OLS with individual dummies and 0.06 for fixed effect model.  Is it the case that in fixed effect model, the fixed effects (individual dummies) are excluded from the calculation of $R^2$?


I have often been curious about the proofs in my Statistical Inference class, but often I have been told that it is not important to know all the details. I have looked into some of the proofs and found that Measure Theory plays a big role in probability. I will be taking Measure Theory soon.   What are some good books that go more in depth regarding these two topics?

I post this question with some personal specifications. I hope it does not overlap with old posted questions.  Recently I strongly feel that I have to review the knowledge of measure theory for the sake of starting my thesis.  I am not totally new with measure theory, since I have taken and past one course at the graduate level. Unfortunately, because the lecturer was not so good at teaching, I followed the course by self-study. Now I feel that all the knowledge has gone after the exam and still don’t have a clear overview on the structure of measure theory. And here come my specified requirements for a reference book.   I wish the book elaborates the proofs, since I will read it on my own again, sadly. And this is the most important criterion for the book. I wish the book covers most of the topics in measure theory. Although the topic of my thesis is on stochastic integration, I do want to review measure theory at a more general level, which means it could emphasize on both aspects of analysis and probability. If such a condition cannot be achieved, I'd like to more focus on probability. I wish the book could deal with convergences and uniform integrability carefully, as Chung’s probability book.    My expectation is after thorough reading, I could have strong background to start a thesis on stochastic integration at an analytic level.  Sorry for such a tedious question.  P.S: the textbook I used is Schilling’s book: measures, integrals and martingales. It is a pretty good textbook, but misprints really ruin the fun of reading.


I'm looking at a handful of files on my system with setuid permission on my system, by running:  sudo find / -perm -4000   I noticed that /bin/ping shows up on the list.  Can anyone explain why ping requires setuid permission?

Ping is a a program owned by root with the user id bit set.  $ ls -l `which ping` -rwsr-xr-x 1 root root 35752 Nov  4  2011 /bin/ping   As I understand it, if a user runs the ping process, then the effective user id will change from the real user id (i.e. the user id of the person who launched the process) to the user id root. However when I try this and look at the output of ps to see if the ping process is running as the root user, I still get the real user id showing.  ps -e -o user,ruser,euser,cmd,args | grep ping sashan   sashan   sashan   ping -i 10 -c 1000 www.goog ping -i 10 -c 1000 www.google.com


So I have no errors in my code but for some reason my search is returning the true result no matter if the array contains it  public static void linSrch(String[] names) {     Scanner inputDevice = new Scanner(System. in );     System.out.println("Please enter search");     String search;     search = inputDevice.nextLine();     boolean searchReturn;     for (int index = 0; index < names.length - 1; index++) {         if (names[index] == search) {             searchReturn = true;         }     }     if (searchReturn = true) {         System.out.println(search + " is found in the array.");     } else {         System.out.println(search + " not found in the array");     } }

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


I've seen in Wolfram Alpha that $$\sum_{i=0}^{\infty} \frac{i^2}{i!}=2e$$ but I have no idea how to prove that.  Can anyone help me?  Thanks.

For some series, it is easy to say whether it is convergent or not by the "convergence test", e.g., ratio test. However, it is nontrivial to calculate the value of the sum when the series converges. The question is motivated from the simple exercise to determining whether the series $\sum\limits_{k=1}^{\infty}\frac{k^2}{k!}$ is convergent. One may immediately get that it is convergent by the ratio test. So here is my question:     What's the value of $$\sum_{k=1}^{\infty}\frac{k^2}{k!}?$$


Assuming i have a stored procedure (example as follows)   CREATE OR ALTER PROCEDURE test AS BEGIN     SELECT * FROM sys.tables;     WAITFOR DELAY '01:00'     SELECT * FROM sys.tables END GO;    and I have a c# invocation of a SQLCommand that runs a stored procedure as follows  using (var connection = new SqlConnection(connectionString)){         connection.Open();         using(var command = new SqlCommand("test", connection)){             command.CommandType = CommandType.StoredProcedure;             command.ExecuteNonQuery();         }     }   Is there a way for me to get at the underlying sql statement currently being executed within the stored procedure?   What I would like to get is the ability to log, "SELECT * FROM sys.tables", "WAITFOR DELAY '01:00'", etc.

Any pointers on how I can programmatically get exactly the identical stored procedure source from SQL Server 2005, as when I right-click on that stored procedure in SQL Server Management Studio and select modify?  I'm trying using SMO, but there are some textual differences.  The procedure always has CREATE, not ALTER, and there are some differences in the header, such as missing GOs in the version I'm getting programmatically.  I can fix these up, but perhaps there is a better way?  Again, I'm in SQL Server 2005, using SMSE.  Using SMO via Visual Studio 8 2008.  Update:  Gotten some answers that tell the basics of how to retrieve the stored procedure.  What I'm looking for is retrieving the text identical (or nearly identical) to what the GUI generates.    Example:  for sp_mysp, right-click in Management Studio, select modify.  This generates:      USE [MY_DB]       GO       /****** Object:  StoredProcedure [dbo].[sp_mysp]    Script Date: 01/21/2009 17:43:18 ******/       SET ANSI_NULLS ON       GO       SET QUOTED_IDENTIFIER ON       GO       -- =============================================     -- Author:           -- Create date:      -- Description:      -- =============================================     ALTER PROCEDURE [dbo].[sp_mysp]   I'd like to programmatically get the same thing (notice the GOs in the header, and the fact that it's an ALTER PROCEDURE.  Ideally, I'd like to get this with minimal programmatic fixing up of the source retrieved.  I'd be happy to only get something that differed in the Script Date details . . .


Is it grammatically correct to use the singular?     Neither sympathy nor empathy is relevant to the decision.   Or should I be using the plural form?     Neither sympathy nor empathy are relevant to the decision.

What is the correct sentence?  Neither Michael nor Albert is correct.   Neither Michael nor Albert are correct.


I'm working in a framework written by another developer and I'm only allowed to touch the scss(css) but not the html. I am writing in scss and I need to change the style of an h1 inside of a div with the class "13_steps". But I can't get my style to take effect.   Example html:

Headline

   Example scss:  .13_steps {    h1 {      color: black;    } }   I have a vague recollection of once reading that you should not name selectors "[some number]_[name]"... but I can't remember why or even if that is my problem. Does anyone have any info or ideas?

What characters/symbols are allowed within the CSS class selectors? I know that the following characters are invalid, but what characters are valid?  ~ ! @ $ % ^ & * ( ) + = , . / ' ; : " ? > < [ ] \ { } | ` #


I have used the below query with a constraint to check the values which are inserting to the stu_code column start with 's'.  mysql> CREATE TABLE student_info(        no INT(3) PRIMARY KEY,        stu_code VARCHAR(10),        CHECK (stu_code like 's%'));  Query OK, 0 rows affected (2.68 sec)   but it does not work. When I inserting the values (like below) I can insert values which are not starting with 's'.  mysql> INSERT INTO student_info VALUES (1,'k001'); Query OK, 1 rows affected (0.47 sec)   I am beginer with SQL, Can anyone help me find out what is the issue?

I have the following table.   create table test (    id smallint unsigned AUTO_INCREMENT,    age tinyint not null,    primary key(id),    check (age<20) );   The problem is that the CHECK constraint does not work on the age column. For example, when I insert 222 for the age field MySQL accepts it.


Consider the following table structure:  UserGroup(ie. 'Admin')     ID = 'Admin'     ApplicationFK = 'App1'  JoinTable     UserGroupFK = 'Admin'     PermissionFK = 'Approve'     PermissionValue = 'READ'  Permission(ie. 'Approve')     ID = 'Approve'     ApplicationFK = 'App2'  UserPermission     UserFK = 'John'     PermissionFK = 'Approve'     PermissionValue = 'WRITE'  User     ID = 'John'   Where you have a jointable between UserGroup and Permission, with both UserGroup and Permission having foreign keys to Application.  Is there any way to enforce integrity, to avoid the situation above, where the ApplicationFKs don't match? I cannot simply remove one of the Foreign Keys, as it is possible to have a Permission without any UserGroups, and possible to have a UserGroup without any permissions.

I have following database design (by => foreign key constraints are depicted):   Company[id] CompanyRealm[id, company_id=>Company.id]many2many  Project[id, company_id=>Company.id] ProjectRealm[id, project_id=>Project.id, company_realm_id=>CompanyRealm.id]many2many   Problem is that provided database design allows inconsistent data. For example:   Company1(id=1) Company2(id=2) CompanyRealm(id=11, company_id=1) Project(id=33, company_id=2) ProjectRealm(id=44, project_id=33, company_realm_id=11)   (Company can have many Realms, Project belong to Company and  may concern any number of company's Realms)  ProjectRealm refers to two different companies:   Company1 (via CompanyRealm); and Company2 (via Project).    Is something wrong with my DB design? If yes - which prescriptions are violated? If no - how to prevent incorrect data insertion (via constraint? trigger with exception?)


I'm recently getting the error below:     HTTP error 0 occurred when trying to fetch .   Downloading updates failed:      Failed to download captcha from       Blockquote   I'm running my website on a shared platform, so I can't change the parameters of PHP...  Based on this long thread drupal dot org/node/247009 I have already tried several many potential solution with no luck so far. This is what I tried and it did not work:   gave 777 recursive permissions to tmp and site/default/ tried on different browsers (Edge, Firefox, Chrome) in jquery update module I changed the jquery default version to 1.10 I set the jquery source from google, and I set the jquery to non-minified I checked and in settings.php I do not have any base url set the file which failes to be downloaded is very small in size 103KB, so I     guess it's not about uploading to large files I checked my PHP version and it did not change recently it;s 5.3.29 I also checked the PHP memory limit and it's set to 256MB which to me it's not that low for uploading a 103KB file  I I tried the update of a different module, and I get the same error   What could be the problem? Where to look next?

I have an error in my Drupal 7 site when I try to install any module.   If I try the Install from a URL I get:     HTTP error 0 occurred when trying to fetch .      Unable to retrieve Drupal project from .   If I try Upload a module or theme archive to install I get:     An AJAX HTTP request terminated abnormally. Debugging information follows. Path: StatusText: ResponseText: ReadyState: 4   The error page shows me:     Notice: Undefined index: log in update_authorize_install_batch_finished() (line 235 of V:\www\site\modules\update\update.authorize.inc).   Warning: Invalid argument supplied for foreach() in update_authorize_install_batch_finished() (line 235 of V:\www\site\modules\update\update.authorize.inc).   Notice: Undefined index: log in update_authorize_install_batch_finished() (line 276 of V:\www\site\modules\update\update.authorize.inc).   Notice: Undefined index: tasks in update_authorize_install_batch_finished() (line 277 of V:\www\site\modules\update\update.authorize.inc).   Installation failed! See the log below for more information.   Any ideas on how I can troubleshoot this?


Is the cardinal of the set of differentiable functions = card of real numbers? I was thinking of using squeeze rule to show. I know that all differentiable functions are continuous. So card differentiable functions is more than equal to c, but how do I show that its less than or equal to c?

Is the cardinality of  $$X = \{f: \Bbb R \to \Bbb R \;|\; f \text{ is differentiable everywhere}\}$$ the same as $\Bbb R$? How to prove it?


This morning, WinEdt 10.2 start exhibiting the problem with Adobe Reader DC in that I have to close the reader each time I want to compile with PDFTexify.  Here is the error that I get:  Cannot Open DDE Link to: C:\Program Files (x86)\Adobe\Acrobat Reader DC\Reader\AcroRD32.exe Service" AcroviewA17 Topic: Control   I have already tried reinstalling WinEdt with the latest build and the Adobe Reader is up-to-date.  I have also tried the modifications discussed in previous forums in editing through the options interface.    I have also tried editing the Adobe.edt file which now reads:  // As of Adobe DC DDE Service is version-dependent (eg. AcroViewR17 or AcroViewA17)  Assign(!'Acro-DDE_Service',!'Acroview');    // Adobe Blues: Registry does not contain proper value for Adobe X!   // http://forums.adobe.com/message/3323310   IfNum('%!3','10','<',!'JMP(!"DDE_OK");');   // Add R or A + Major Version...   //UF LetReg(4,'R%!3');   LetReg(4,'R17');   //\UF   FindInString("%$('PDF-View');",'Acrobat.exe',1,2,1000,1);   //UF IfOK(!"LetReg(4,'A%!3');");   IfOK(!"LetReg(4,'A18');");   //\UF   Assign(!'Acro-DDE_Service','%$("Acro-DDE_Service");%!4');   // Prompt('DDE Service: %$("Acro-DDE_Service");');   Does anyone have any other suggestions?

While using the 2017 release of Adobe Acrobat DC, I get the error    every time I run PDFLatex with my PDF open. When I use PDF Search, I get the same error.   Does anybody know what do I have to change in the .edt files to make it work?


How do I copy files in others account in Linux to my Windows PC. I have .  I’ve the access permission to other account (sudo).

I'm using WinSCP to access Unix computers. How can I change user after I have logged into a Unix server using WinSCP?  E.g. I have personal account in Unix computer A. I can log into this computer using PuTTY and then change user to root user  $sudo /usr/bin/su - rootuser   How can I do the same thing using WinSCP? I don't know the password for rootuser.


Problem let $\mathrm P$ be the set of prime numbers ; $\forall(p,p+2)\in\mathrm P^2: p\times(p+2)=A_1 ,\quad A\in\mathrm N$ where $A_1$is written on the figure : $A_1=a_1^1a_2^1a_3^1....a_{n_0}^1$ where $(a_i^1)_{1\leq i\leq n_0}\subset\mathrm N $ So we put : $$g(n_0)=\displaystyle\sum_{i=1}^{i=n_0}a_i^1=a_1^1..a_{n_0}^1=A_2\quad ,A_2\in\mathrm N$$ Where $A_2$ is written on the figure : $A_2=a_1^2a_2^2a_3^2...a_{n_1}^2,\quad (a_i^2)_{1\leq i\leq n_1} \subset \mathrm N \quad \quad \text{and}\quad  n_1\leq n_0$ So we find : $$g(n_1)=\displaystyle\sum_{i=1}^{i=n_1}a_i^2$$ we reput the step until we finally get : $$g(1)=A_k=a_1^k=8 $$ for any $(p,p+2)\in \mathrm P^2$ Exemples: $$5\times7=35,\quad g(1)=3+5=8$$ $$11\times13=143,\quad g(1)=1+4+3=8$$ $$29\times31=899,\quad g(2)=8+9+9=26\implies g(1)=2+6=8$$ $$2027\times2029=4204088,\quad g(2)=6+8+5+5+8+3=35\implies g(1)=3+5=8$$ $$7877\times7879=62062883,\quad g(2)=6+2+6+2+8+8+3=35\implies g(1)=3+5=8$$  I applied these steps to almost all pairs of less than $3000$ and other pairs greater than $5000$ and i did not find any pair of primes refuting this property I found this problem whill studying one of this articles to prove thet prime dont'end using the topologies in this  I wanted to ask if this problem existes before or not because i searched and found nothing about it So this problem did not exist, how then can I prove or disprove this problem ,even though I did not find any in these results I await  your suggestions and information about this ,thank you

It appears that the product of any pair of twin primes (excluding the first pair 3 and 5) yields a semi prime whose digital root is equal to $8$.   Example: $$ 17 \cdot 19 = 323 $$ The digital root of $323$ is $8$.  I've tested the first twenty and a bunch of random large ones such as $$ 8231 \cdot 8233 = 67765823 $$ Its digital root is also $8$.  As an amateur in advanced mathematics I'm curious to know how I could prove or disprove this conjecture. All tips are welcomed and much appreciated. Thanks.


I am born in the U.K. if I bring my birth certificate is that good evidence that I’m from the uk. Either by Eurostar or flight

I am a British citizen. I was born in Britain, but I have Mauritius passport. I would like to do a return trip to Paris on the Eurostar. Can I use my Mauritius passport?


Every-time I have to install a new Debian Linux system I encounter the same troubles with locales -- I do precisely want English system language with standards set to the country where I live, i.e. Germany.  The debian installer, and probably others, is asking at installation time for your "preferred" language. And every time I choose English. But then, I cannot add the standard locales of my country, because only English speaking countries are shown for the previously chosen language.  It's clear. After installation with enough manual fiddling it's achievable. And there is also a workaround (at least for European-ish users)  by using en_IE.UTF-8 or en_DK.UTF-8 . However, this doesn't answer the question: Why it is so difficult to combine the preferred English system language with specific locales? I want to understand the reason/s and if there are any risks.  (Why do I want this? Because I can't see any advantage in (partially) traduced messages and software. Even more, it is much harder to find help when researching with English-foreign errors and messages got for the encountered issues.)  My actual configuration, AFAIK it works fine:  $ locale LANG=en_US.UTF-8 LANGUAGE= LC_CTYPE="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_COLLATE="en_US.UTF-8" LC_MONETARY=de_DE.UTF-8 LC_MESSAGES="en_US.UTF-8" LC_PAPER=de_DE.UTF-8 LC_NAME=de_DE.UTF-8 LC_ADDRESS=de_DE.UTF-8 LC_TELEPHONE=de_DE.UTF-8 LC_MEASUREMENT=de_DE.UTF-8 LC_IDENTIFICATION=de_DE.UTF-8 LC_ALL=

I've installed Debian 7 i386 on my VPS (OpenVZ). Everything works fine, except locales - any attempt to install anything shows:  [...] perl: warning: Setting locale failed. perl: warning: Please check that your locale settings:     LANGUAGE = (unset),     LC_ALL = (unset),     LANG = "pl_PL.UTF-8"     are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory [...]   What I've tried:   Generating locales myself - update-locale LC_ALL="pl_PL.UTF-8" - shows:  apt-get install --reinstall locales  The same with dpkg-reconfigure locales + setting pl_PL.UTF-8, pl_PL.ISO-8859-2 or even en_US:  export LC_ALL=pl_PL.UTF-8 (even on root):  -bash: warning: setlocale: LC_ALL: cannot change locale (pl_PL.UTF-8)    Here is what shows locale:  root:~# locale locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory LANG=pl_PL.UTF-8 LANGUAGE= LC_CTYPE="pl_PL.UTF-8" LC_NUMERIC="pl_PL.UTF-8" LC_TIME="pl_PL.UTF-8" LC_COLLATE="pl_PL.UTF-8" LC_MONETARY="pl_PL.UTF-8" LC_MESSAGES="pl_PL.UTF-8" LC_PAPER="pl_PL.UTF-8" LC_NAME="pl_PL.UTF-8" LC_ADDRESS="pl_PL.UTF-8" LC_TELEPHONE="pl_PL.UTF-8" LC_MEASUREMENT="pl_PL.UTF-8" LC_IDENTIFICATION="pl_PL.UTF-8" LC_ALL=   Nothing interesting found in /var/log. Even changing repo to official + purge and manual installation locales doesn't solve my problem, which manifests itself on each fresh installation of Debian 7.


I'm working in django, but standard python solution is ok too.    I'm converting a code which uses a naive-datetime to use aware-datetime.  Below is the original code:  today = datetime.today() MyClass.objects.filter(datetimefield__range=(today, today+datetime.timedelta(1)) )   How do I convert it to use timezone-aware time?    If the time is jun/3rd/7:20pm locally, I'd like to get datetime range of [jun/3rd/00:00am, jun/4th/00:00am]  (midnight to midnight which will include now)

The best I can come up with for now is this monstrosity:  >>> datetime.utcnow() \ ...   .replace(tzinfo=pytz.UTC) \ ...   .astimezone(pytz.timezone("Australia/Melbourne")) \ ...   .replace(hour=0,minute=0,second=0,microsecond=0) \ ...   .astimezone(pytz.UTC) \ ...   .replace(tzinfo=None) datetime.datetime(2008, 12, 16, 13, 0)   I.e., in English, get the current time (in UTC), convert it to some other timezone, set the time to midnight, then convert back to UTC.  I'm not just using now() or localtime() as that would use the server's timezone, not the user's timezone.  I can't help feeling I'm missing something, any ideas?


I'm relatively new to this, I got no idea how to proceed at all. I'm just bad at this chapter :(  $$ m\mid (ab- (a \bmod m \cdot  b \bmod m)). $$ How do I proceed after that? Is this even the first step?

For all $n \in \mathbb{N}$, $n > 1$ and $x,y \in \mathbb{Z}$ prove that      \begin{equation}   (x+y) \text{ mod } n   = ((x \text{ mod } n)+(y \text{ mod } n))\text{ mod } n. \end{equation}   Would this be a proof if I say:  Let $x = x' \text{ mod } n$ and let $y=y' \text{ mod } n$. Then  \begin{equation}   x+y = x'+y' \text{ mod } n. \end{equation}  Now, if we look at the current thing we want prove, this will follow:  \begin{equation}   x+y \text { mod } n = (x \text{ mod } n + y \text{ mod } n) \text{ mod } n. \end{equation}    I'm not sure if this is allowed or will count as a "proof" at all. Maybe you can show me some other ways of doing this, more precise ones?


I'm working on a research project that includes a survey of academics in a specific field. One method we've discussed for building a sample frame and obtaining contact information for potential respondents involves using web scraping to automatically obtain email addresses from various University websites. Names would be obtained by downloading citations for papers related to our topic, then we would use a script to search the web for email addresses that match those names. I'm not sure that this is an appropriate method for obtaining contact information, and have found some sources online that suggest my hunch is correct. However, most discussion of these methods relates to marketing research, rather than an academic context.  What do you think? Are there rules or guidance about this that I haven't found (I've read the CASRO and ESOMAR guidelines for research market which suggest that web scraping/email harvesting is not appropriate).

I am wondering whether the following research practice is ethical.  A software engineering researcher downloads source code repositories from , a large source of publicly available open source code.  The researcher searches the git commit logs to find email addresses of software developers who have committed to a project, and uses these email addresses to send them an email asking them to participate in a survey.  If the recipient clicks on the link to the survey, the survey contains an appropriate briefing and obtains informed consent.  The researcher follows all institutional and legal requirements related to human subjects research.  The researcher limits the number of emails sent to only the number of participants they think they will need to test their hypotheses.  However, at least one recipient of this email is annoyed that the researcher obtained their email address in this fashion and sent them unsolicited email.  Is this an ethical research practice?  In particular, what would be the relevant ethical principles or ethical framework for analyzing this question?  I've read a bunch of papers and backgrounders on ethics in human subject research and in engineering research, but they seem focused on other issues.  Are there accepted norms or guidelines relating to this sort of situation?  Has it been considered in other fields, such as the social sciences?  A possible argument that the practice is ethical: The data source is publicly available, and the email addresses were collected from this publicly available data.  Developers chose to make their software repository publicly available, and they should assume that any information contained in it are public.  Developers who don't want to be contacted could have configured their git client specially to use a different email address.  The research will benefit our understanding of the science of software development.  Subjects have an opportunity to decide whether or not to participate in the survey.  Participant confidentiality will be protected, and all responses will be treated anonymously.  The research complies with all legal and compliance requirements.  From a legal perspective, the emails are not "spam", since the unsolicited email was not sent for a commercial purpose.  A possible argument that the practice is unethical: Software developers probably would not expect someone to scrape email addresses from the git commit logs.  Their email address might be contained in a publicly available data set, but some developers might expect/consider the information private, or at least not public and free for unrestricted use.  Some developers might object that it is one thing to use email addresses that are publicly listed on their Github profile page, but it is another thing to extract private email addresses that are provided as part of their git configuration, and that their understanding of social norms is that the email addresses automatically inserted into the commit logs by their git client were not intended for this purpose.  Some software developers might object to having an unwanted email message in their inbox or find the practices "creepy".    Please note: I am not asking about IRBs, legal requirements, or compliance.  I am super-familiar with those considerations.  Assume that the researcher has complied faithfully with all of those requirements that are applicable in their country.  I'm not asking about that aspect.  In my view, researchers have an independent obligation to conduct research in an ethical manner, and to exercise their own judgement in avoiding unethical behavior, even if is legally permitted or approved by an IRB.


I'm having trouble proving this. I am able to prove other metrics, I think it is possibly the format of the railway metric that is confusing me...  Consider the function $d : \mathbb{R}^2 \times \mathbb{R}^2 \rightarrow [0, \infty)$ given by  $d(x,y)=\begin{cases} d_2(x,y)~\text{if $x,y,0$ are collinear}\\d_2(x,0) + d_2(0,y) ~\text{otherwise}\end{cases}$  I have also tried to attach a photo of the question)

I am trying to work just one case of showing that the French railways metric defined by a metric space $(\mathbb{R}^2,d)$ is actually a metric:  $$d(x,y) = \begin{cases} \|x-y\|, & \text{if $x,y,0$ are collinear;} \\ \|x\| +\|y\|, & \text{otherwise} \end{cases}$$  I am trying to show the case that if $x=y$, then $d(x,y)=0$. I have been able to show that if $x=y$, then $\|x-y\|=0$, but am having a hard time showing that if $x=y$, then  $\|x\| +\|y\|=0$. Thank you!


I'm working on a C# WPF application. I'm using a DLL (not developed by me). I'm using it like this (simplified):  try {     Bitmap bmp = new Bitmap(filePath);      // Use the DLL     var worker = theDLL.loadImage(bmp);      status state = worker.start();      if (state = theDLL.sta.OK)     {         return "OK"     }     else     {         state = worker.tryOtherMethod();     } } catch (Exception e) {     // Do something with e }   Sometimes (not always) I have a Unhandled exception. This exception is not catch and my application crash :     An invalid parameter was passed to a function that considers invalid   parameters fatal.   I saw that this exception comes from C++ code but i'm unable to catch it (even with AppDomain.CurrentDomain.UnhandledException or Dispatcher.UnhandledException).   How can I prevent the crash ?  Edit:  I've try to catch the exception with catch alone and catch (Win32Exception e) but both didn't solve my problem.  I still have this error :

In C# code can you catch a native exception thrown from deep in some unmanaged library? If so do you need to do anything differently to catch it or does a standard try...catch get it?


I am working on a site where user authentication is used. When user submits the authentication form, browser asks if user wants to remember password. I think that "feature" is very annoying, so I need to tell every browser not to remember that password. I don't want to use AJAX authentication, also autocomplete="off" doesn't work. So I need  to hide characters replacing them by *.

One of the joys of working for a government healthcare agency is having to deal with all of the paranoia around dealing with PHI (Protected Health Information). Don't get me wrong, I'm all for doing everything possible to protect people's personal information (health, financial, surfing habits, etc.), but sometimes people get a little too jumpy.  Case in point: One of our state customers recently found out that the browser provides the handy feature to save your password. We all know that it has been there for a while and is completely optional and is up to the end user to decide whether or not it is a smart decision to use or not. However, there is a bit of an uproar at the moment and we are being demanded to find a way to disable that functionality for our site.  Question: Is there a way for a site to tell the browser not to offer to remember passwords? I've been around web development a long time but don't know that I have come across that before.  Any help is appreciated.


I have a server that runs websites and exim for e-mail. I've added countless RBLs including barracuda to try and cut back on incoming spam. However, they still keep coming in. The clients use RoundCube. Is there a way for them to submit e-mails as spam or something?  Are there any other ways I could try and cut down on the incoming spam?

This is a  about Fighting Spam.   Also related:                    There are so many techniques and so much to know about fighting SPAM. What widely used techniques and technologies are available to Administrator, Domain Owners, and End Users to help keep the junk out of our inboxes?  We're looking for an answer that covers different tech from various angles. The accepted answer should include a variety of technologies (eg SPF/SenderID, DomainKeys/DKIM, Graylisting, DNS RBLs, Reputation Services, Filtering Software [SpamAssassin, etc]); best practices (eg mail on Port 25 should never be allowed to relay, Port 587 should be used; etc), terminology (eg, Open Relay, Backscatter, MSA/MTA/MUA, Spam/Ham), and possibly other techniques.