How can I perform an offline upgrade using Ubiquity on the installation disc?

I'm trying to upgrade an Ubuntu 12.10 installation to Ubuntu 13.04 without an Internet connection. Now that the alternate and desktop CDs have been merged, I'm trying to use the 13.04 Desktop CD in order to upgrade my 12.10 system. In Ubiquity, there is an Upgrade Ubuntu 12.10 to Ubuntu 13.04 option. So I guess this is doable.  Steps to replicate:   In a virtual machine, install a clean, fresh Ubuntu 12.10 system. Apply all available updates; Shutdown the VM; Disconnect network cable from the VM. Make sure your VM has no Internet link -- remember I want to do an offline upgrade; Insert the Ubuntu 13.04 beta 2 installation ISO in the VM. Reboot the VM; Select your desired language, and select Install; On Preparing to install Ubuntu screen, make sure again that you see no Internet connection available. This prerequisite should be marked by an X on this screen. If an Internet link has been found by Ubiquity, disable this connection before continuing; Then, on Installation type screen, observe that the Upgrade Ubuntu 12.10 to Ubuntu 13.04 option is greyed!!! It cannot be selected.   What is strange is the upgrade option as again available if an Internet connection is found by the installer. Repeat the previous steps, but this time, make sure your VM has an Internet link. Back on the Installation type screen, the upgrade option can be selected.  Is this a bug in Ubiquity? Is it normal -- the expected behavior -- for Ubiquity to require an Internet connection in order to perform an upgrade from Ubuntu 12.10 to 13.04?  (Please note that I did not have any problem doing an online upgrade using Software Updater from my current 12.10 install. That is not what I want to achieve -- I already wrote the online upgrade guide. What I want to know is: how can I perform an offline upgrade using Ubiquity on the installation disc?)


I'm trying to .put a pair into a linkedhashmap but when i put 2 or more the size never changes! When i iterate it i get every pair but in random order but the size stays 1. When i hard code the .put (example playerCoords.put(1,"test")) the size changes.  playerCoords = new LinkedHashMap<Integer, String>();  while (message[0] != "234124214") {     message = (String[]) input.readObject();     if (message[0] != null) {         playerCoords.put(Integer.parseInt(message[0]), message[1]);         output.writeObject(playerCoords);         output.flush();     } }   EDIT: When i open the program 1 client connects to the server and his coords and port get written in the linkedhashmap (ex. 25565,"1 1 2") and then another joins (ex/ 25566, "1 2 1") and when I iterate i get both of these examples but the size still is 1!


Is there a way to make a one way mirror? (Cycles)

I'm trying to create a reflection that will repeat an object so it looks like there are infinite but it is only reflecting. Just using white glossy shader doesn't work because it reflects outside.  I'm hoping I can do this with the camera set to orthographic. Probably not though.


Photos taking up storage on iPhone when I have no photos

Problem from iOS 10.1.1 to 10.2.1.  I have no photos at all on my iPhone yet in settings it says my photo library is taking up ~200MB of space. The number of space being taken up keeps changing constantly(in the settings app on my phone). In iTunes, the storage bar at the bottom does(when in the sync menu) not show photos.           What is taking up this storage, and how can I reduce it?  Troubleshooting:   I disabled iCloud photo library and iCloud photo stream, still showing the same thing. Tried doing what @User9125 said, didn't work. I had set the date all the way back when I first got my phone, nothing showed up. Rebooting I had hundreds of photos in Whatsapp, I deleted them but I didn't get the storage back. It didn't even make a dent in the amount of storage being used by Photos so I don't think a third-party app could be taking up this storage. I don't think a system app is taking this space either, because I cleared the pictures in mail and messages. I tried using (through sideloading) in Secure Mode and Fast Mode, but it did not clear up the photos.


Show that $\int^{\infty}_0 \frac{\sin^4 x}{x^4}=\frac{\pi} 3$.

Show that $$\int^{\infty}_0 \left( \frac{\sin x}{x}\right)^4=\frac{\pi} 3$$   Although I know the integral with the index is $1$ and $2$, I have no idea on this one. Please help.


C#: After copying a class the "this" keyword throws an error

I am just about to use the "FusedLocationProvider" from the xamarin sample. When I start it up, it works. It is just one activity and one layout file.  I now added a new class to my project and called it "FindTheLocationNEW" into which I simply copy-pasted everything from the xamarin sample. Now, everything seems to work fine after a few adjustments with the layout file (nothing serious) and only the "this" keyword says:  Cannot convert from "FusedLocationProvider.MainActivity" to "Android.App.PendingIntent".  However, this did work when it was a standalone activity. So I am guessing, the "this" keyword is getting a wrong context.  A bit of the code:  namespace FusedLocationProvider {     [Activity(Label = "FusedLocationProvider", MainLauncher = true)]     public class MainActivity : Activity, GoogleApiClient.IConnectionCallbacks,         GoogleApiClient.IOnConnectionFailedListener, Android.Gms.Location.ILocationListener     {               button2.Click += async delegate {                 if (apiClient.IsConnected)                 {                     button2.Text = "Requesting Location Updates";                      // Setting location priority to PRIORITY_HIGH_ACCURACY (100)                     locRequest.SetPriority(100);                      // Setting interval between updates, in milliseconds                     // NOTE: the default FastestInterval is 1 minute. If you want to receive location updates more than                      // once a minute, you _must_ also change the FastestInterval to be less than or equal to your Interval                     locRequest.SetFastestInterval(500);                     locRequest.SetInterval(1000);                      Log.Debug("LocationRequest", "Request priority set to status code {0}, interval set to {1} ms",                         locRequest.Priority.ToString(), locRequest.Interval.ToString());                      // pass in a location request and LocationListener                     await LocationServices.FusedLocationApi.RequestLocationUpdates(apiClient, locRequest, this); // THIS IS WHERE IT IS NOT WORKING!!!                      // In OnLocationChanged (below), we will make calls to update the UI                     // with the new location data                 }                 else                 {                     Log.Info("LocationClient", "Please wait for Client to connect");                 }             };         }   Any help would be awesome!


Incredible frequency of careless mistakes

Ever since high school, I've had a serious problem with math classes. Be it discrete math, algebra, calculus or linear algebra, I seldom have trouble understanding the texts or lectures, but when it comes to executing calculations on homework and exams, I can never do it: I keep making mistakes. It's been a constant source of frustration, and right now, I'm on the verge of failing linear algebra and second year calculus (which I've been avoiding for as long as I could). I'm currently going through all the exercises and videos on , beginning with one-digit addition, working my way back up to integrals. I was making a lot of mistakes with multiple digit subtraction and multiplication, so initially, I was hopeful that maybe with enough practice in those two things, I'd be good to go again. But it turns out that my mistakes aren't confined to any one task, and the number of mistakes I make per exercise just accumulates as the tasks become more and more computationally involved:  Thinking that 7 + 5 = 13 Neglecting negative signs when transcribing Carrying in multiple-digit addition when a digit hasn't surpassed 10 Multiplying instead of adding Using the wrong exponent laws, log laws, limit laws etc. Mixing up trigonometric function properties Forgetting to reverse signs when expanding negated expressions of multiple terms  A typical page from my notebook:  I've tried everything: going for walks, ensuring that I have good sleep, writing out every step with almost hilarious verbosity, changing rooms, starting with fresh notebooks, reviewing everything I write, trying different notations, heck I even spent a month refining my handwriting and posture for good measure. I'm certain I spend about twice as much time as other people practicing too. I avoid taking other courses in the same semesters that I take math courses. As far as personality goes, in general, I'm not exactly OCD, but I'm not careless either. I probably have more patience than most people -- a bit too much, as my friends would tell me. I'm sure you can also tell from my adequate grammar, punctuation and spelling that I probably don't have any kind of learning disability that would prevent me from following symbolic rules. I've gotten near 100% in a first order logic course too. Yet when I do math, I always screw up. It's been this way for over a decade, maybe more. I don't know what I'm doing wrong anymore, and I'm losing hope. What could I do?


How to deal with a corroded copper water pipe?

We have a corroded copper pipe. I'm not interested in what caused the corrosion.  I just want to know how to treat it. What can I do to stop the corrosion? Paint it?  What would I paint it with?  UPDATE: Please see this post for the condition of the pipe.  Note: the corroded part is the main water line and the valve forward is to our structure.   Can we just replace the corroded section?


Why is there no publisher field on the article entry type in biblatex?  I am using biblatex to create my bibliography, however I can't seem to figure out how to reference a publisher in an article Entry Type.  For example:  The Golden Ratio: A Contrary Viewpoint Clement Falbo The College Mathematics Journal Vol. 36, No. 2 (Mar., 2005), pp. 123-134  (article consists of 12 pages) Published by: Mathematical Association of America   How should I include the information about Mathematical Association of America in my entry?


How to find the week day of (any) given date?

How to find the week day of any given date?  Say we need to know in which week-day was June $25,2019$?


How can I check if a file exists in python?

I am trying to make a python script to make entries in an excel file that will have daily entries. I want to check if a file exists then open it. if the file does not exist then I want to make a new file.  if have used os path exists to see if the file is present       workbook_status = os.path.exists("/log/"+workbookname+".xlxs")      if  workbook_status = "True":      # i want to open the file      Else:      #i want to create a new file


Can't boot, stuck on grub rescue with no modules?

I tried installing Ubuntu 12.04 on my new computer (I have already installed it on my old computer, and everything is fine). For some reason, grub said it was not installed. Upon reboot, I reach the grub rescue screen with no bootable device. I tried using normal.mod, but I have no modules. I can't access my bios, and I basically cannot even boot to reinstall. I have no idea what to do.


This is now my homepage and my articles there is with full text this look bad e.g.:      How i can edit this to look like from this photo so with images and e.g. some of text and after write ''read more'' or just ''...'' which redirect on articles      Thanks


What force other than gravity acts on objects in Earth orbit?  Without such force, continued orbit would be impossible, as the object would be drawn to the Earth.


I've been struggling with ubuntu installation in the last few days. I got a new Lenovo B50-80 with FreeDos and wanted to install Windows 7 or 10 alongside with Ubuntu 14.04 on a Samsung SSD 840 drive.   Here is what I did:  1)Installed Windows 10 by usb then tried to install ubuntu from usb but it didn't recognize windows even though it could see the different partitions. I left some unpartitioned space but when I created the partition it said that it didn't find the Boot partition or something.  2)Tried installing Windows 7 from cd rom and then again ubuntu in both UEFI and Legacy mode but this time it couldn't even see the different partitions and was just showing everything unallocated.  I'm kinda desperate at the moment, any advice?  thanks


Does Ubuntu 12.04 LTS runs on my computer? I need help

I'm learning on my school about operating system's installation, Ubuntu looks so beauty and fast, even on that old computers.   I have an Emachines L4030, originally with Windows XP Starter Edition, later I upgraded it to Windows XP Professional SP3. Here is my system hardware:   Procesador Intel Celeron D355 3.33GHz,256 KB L2 de Cache 533 MHz FSB  Video Intel Graphics Media Accelerator 900 con ranura PC-IExpress Disponible  HDD 80 GB SATA  Memory 256 MB DDR2 SDRAM    I want to learn about another kind of systems, I don't want to throw Windows to the trash because I still need it for school, I was thinking on a partition (20GB for XP- 60GB for Ubuntu) but I don't know if Ubuntu will run as I want to with my hardware  I'M SORRY! I forgot to tell you guys that I upgraded the RAM to 1.7GB, I copied the info from internet and I didn't remember the upgrade. Can I use Ubuntu with that upgrade?


How to reference equations using letters and numbers

Sometimes it is convenient to refer to a group of equations by a letter and a number.  For example:   2+1   (A1) 2+4   (A2) x^4   (B3) x^e   (B4)   Placing  \tag{A\theequation}\label{eqn:thisone}\stepcounter{equation}} instead of just \label{eqn:thisone} works, but seems hacky (especially manually stepping the counter).   Is there a better way?


How Do I Pass PictureBox and Label Through Functions?

I'm working in a GUI environment in Visual Studio 2012  void dealCard(PictureBox swag, Label swaggy) {     swag.Image = imageListCards->Images[deck[cardCounter].index];     swaggy.Text = deck[cardCounter].name + " of " + deck[cardCounter].suit + ", " + deck[cardCounter].value;      if(cardCounter == 51)         cardCounter = 0;     else         cardCounter++;  }  void dealHand(PictureBox swag, PictureBox swag2, Label swaggy, Label swaggy2) {     dealCard(pictureBoxCard4, labelCard4);     dealCard(pictureBoxCard5, labelCard5); }      pictureBoxCard4, labelCard4 etc are already in the form that I'm working with. It's not compiling the part dealCard(pictureBoxCard4, labelCard4) or the one below


Do we still need screensavers to "protect" LCD from damage

:     Initially designed to prevent phosphor burn-in on CRT and plasma   computer monitors (hence the name)...   So, does it make sense to setup screensaver on LCD display?


Creating multidimensional array with alpha key

I am writing a PHP plugin, which builds a multidimensional array, in the format below, so that it can be passed back to the template system and parsed as tags.  I am fetching the information from a database:  $SQL = SELECT `id`, `name`, `description` FROM (`events`) WHERE `event_category_id` = '1' AND `active` = 1 ORDER BY `name` asc   This is the array structure required:     Array (  [A] => Array (      [0] => Array(         [event_id] => 1         [event_name] => A - this event name starts with the letter A          [event_description] => Example Description)      [1] => Array(         [event_id] => 6         [event_name] => AB - this event ALSO starts with the letter A          [event_description] => Example Description)         )  [B] => Array (      [0] => Array(         [event_id] => 3         [event_name] => BA - Event name starts with letter B         [event_description] => Example Description)      [1] => Array(         [event_id] => 5         [event_name] => BB - Event name starts with letter B         [event_description] => Example Description)         ) )   Could someone point me in the right direction, so that from the returned data, it splits the events into the appropriate keys (alphabetical key), sored alpha by the event_name.  The end result is to have this  A  - Ambulance Training  - Apple Bobbing B  - Badminton  - Bowling


I'm new using latex and I want to do a colored table for my work. I have the following code:  \documentclass[11pt, oneside]{book} \usepackage[table]{xcolor} \usepackage{hhline} \newcommand{\x}{\cellcolor[gray]{0.8}} \usepackage{multirow} \usepackage{rotating} \usepackage{colortbl}  \begin{document} \begin{table}[h!] \caption{List of proposed tasks \label{table_tasks}} \begin{center} \begin{tabular}{|c|c|c|c|c|c|c|c|} \cline{3-8} \multicolumn{1}{c}{} & \multicolumn{1}{c|}{} & \multicolumn{3}{c|}{F1} & \multicolumn{3}{c|}{F2}\\ \cline{3-8} \multicolumn{1}{c}{} & \multicolumn{1}{c|}{} & A1 & A2 & A3 & B1 & B2 & B3\\ \hline \multicolumn{1}{|c|}{\multirow{8}{*}{\rotatebox[origin=c]{90}{Year 1}}} & M &\x & \x & \x & & &\\ \cline{2-8} & J &\x & \x & \x & & &\\ \cline{2-8} & J &\x & \x & \x & & &\\ \cline{2-8} & A &   &    & \x & & &\\ \cline{2-8} & S &   &    & \x & & &\\ \cline{2-8} & O &   &    &    & \x & \x & \\ \cline{2-8} & N &   &    &    & \x & \x & \\ \cline{2-8} & D &   &    &    & \x & \x & \\ \hline \multicolumn{1}{|c|}{\multirow{12}{*}{\rotatebox[origin=c]{90}{Year 2}}} & J &   &    &    & \x & \x & \\ \cline{2-8} & F &   &    &    & \x & \x & \\ \cline{2-8} & M &   &    &    &  &  & \x \\ \cline{2-8} & A &   &    &    &  &  & \x \\ \cline{2-8} & M &   &    &    &  &  & \x \\ \cline{2-8} & J &   &    &    &  &  & \x \\ \cline{2-8} & J &   &    &    &  &  & \x \\ \cline{2-8} & A &   &    &    &  &  & \x \\ \cline{2-8} & S &   &    &    &  &  & \x \\ \cline{2-8} & O &   &    &    &  &  & \x \\ \cline{2-8} & N &   &    &    &  &  & \x \\ \cline{2-8} & D &   &    &    &  &  & \x \\ \cline{2-8} \hline \end{tabular} \end{center} \end{table}  \end{document}   The problem is when I use \cellcolor, color overwrites the table borders. What should I do to fix this problem? I would try using \hhline, but I don't understand the command when I want to color between two or more cells. Thanks in advance


What are the benefits of the two permutation tables in DES?

Why do we use a permutation table in the first step of  and one at the end of the algorithm?


Managing multiple asynchronous NSURLConnection connections

I have a ton of repeating code in my class that looks like the following:  NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request                                                               delegate:self];   The problem with asynchronous requests is when you have various requests going off, and you have a delegate assigned to treat them all as one entity, a lot of branching and ugly code begins to formulate going:  What kind of data are we getting back? If it contains this, do that, else do other. It would be useful I think to be able to tag these asynchronous requests, kind of like you're able to tag views with IDs.   I was curious what strategy is most efficient for managing a class that handles multiple asynchronous requests.


If we know that $cb'=da'$ and if we know that $\gcd(a',b')=1$ then show that $c=ka'$ and $d=kd'$ for some $k\in\mathbb{N}$. My attempt : since $\gcd(a'b')=1\implies a'u+b'v=1$ by multiplying by $c$ we get that $a'cu+b'cv=c$. Which indcates that that $a'$ divides $c$. Is this a valid proof for $c=ka'$?


Specs of my laptop are: processor: AMD E1-2500 graphics: Radeon HD 8240. Whenever I try to install linux in it, it gives some errors. In ubuntu's case, it does not boot, and the screen just goes black(when I change to UEFI boot, it goes white). In opensuse's case, it freezed but I was able to look at terminal output and it said that it detected some CPU lockup. I have had Fedora on the same laptop for some time until an update messed it up and it again gave CPU lockup error, so I am guessing Ubuntu has the same problem. My guess is that new kernels have that issue with my processor, since I don't think I have hardware problems, as I run windows without any issue(also I was running fedora before some update).  How can I solve this problem?


Why are queries parsed in such a way that disallows the use of column aliases in most clauses?

While trying to write a query, I found out (the hard way) that SQL Server parses WHEREs in a query long before parsing the SELECTs when executing a query.  The  say that the general logical parsing order is such that SELECT is parsed nearly last (thus resulting in "no such object [alias]" errors when trying to use a column alias in other clauses). There was even  to allow for aliases to be used anywhere, which was shot down by the Microsoft team, citing ANSI standards compliance issues (which suggests that this behavior is part of the ANSI standard).  As a programmer (not a DBA), I found this behavior somewhat confusing, since it seems to me that it largely defeats the purpose of having column aliases (or, at the very least, column aliases could be made significantly more powerful if they were parsed earlier in the query execution), since the only place you can actually use the aliases is in ORDER BY. As a programmer, it seems like it's missing a huge opportunity for making queries more powerful, convenient, and DRY.  It looks like it's such a glaring issue that it stands to reason, then, that there are other reasons for deciding that column aliases shouldn't be allowed in anything other than SELECT and ORDER BY, but what are those reasons?


Is the choice of epsilon delta free in limit definition?

We use limit definition as: $$  \lim_{x \to a} f(x)=L $$ if  $$   \forall \varepsilon > 0 \quad \exists \delta  > 0 \quad (|x−a| < \delta \implies |f(x)−L| < \varepsilon) $$ But why we cannot use: $$   \lim_{x \to a} f(x) = L $$ if  $$   \forall \delta > 0 \quad \exists \varepsilon > 0 \quad (|x−a| < \delta \implies |f(x)−L| < \varepsilon) $$


Why do two blurry shadows, when brought close to each other, appear to "bulge" and merge?

I have recently noticed that when two objects with blurry shadows cast by the same light source are brought close to each other, their shadows appear to merge in a way where one shadow appears to "bulge" and meet the other even though the two objects are not in contact. I noticed this in my bathroom while I was brushing my teeth. Here is a gif of the same:  I thought that this might have to do with diffraction (although diffraction is a phenomenon that only occurs when light meets objects that are of size comparable to its wavelength, which is not the case here) or the umbrae and penumbrae of the blurry shadows but I'm not sure. I am aware of  question that seems to ask about a similar phenomenon, but have decided to post mine anyway because:  It is related to the shadows cast by the Sun while in my case it is just a bathroom light The answer to it, although a fantastic one, concludes that this effect is captured by the camera due to the limitations of its sensor even though I was able to capture it on my phone with high resolution and the video is indistinguishable from what I saw with my own eyes. Moreover, my bathroom is not brightly lit at all, which is what the answer suggests is required for this effect to be seen or captured by the camera.  Hence, I am inclined to believe that there is something more to it. I was also able to easily recreate this effect using my table lamp, and found that the object that is further from the light source seems to be the one whose shadow "bulges" outward towards the shadow of the object closer to the source of light. This agrees with the gif above as my finger in it is closer to the bathroom light than the faucet, which is the one whose shadow appears to bulge towards the shadow of my finger. It also seems that the blurrier the shadow (i.e. the closer the object is to the light source), the greater is the "bulging" effect although I have not thoroughly tested this. Does anyone have a clear explanation for this phenomenon? Edit While searching about this phenomenon on the web, I came across  Wikipedia page that describes it as the "Shadow blister effect". Although the page is pretty barebones and lacks citations, it seems to agree with my observations about the positions of objects with respect to the light source and each other, and suggests that:  The effect takes place when two objects are located at varying distances between a non-point light source and a backdrop upon which their shadows are cast. As the two objects move transversely such that their shadows approach each other, the object nearest the light source will begin blocking light from reaching the inside of the other object's penumbra, thereby expanding its umbra. This expansion of the further object's umbra will continue until the umbras of both objects meet. This effect can be demonstrated and understood using ray theory.


rearrangement of the alternating harmonic series

The alternating harmonic series $a:=\sum_{n=1}^{\infty}{\frac{(-1)^{n-1}}n}$ converges by the Leibnitz-criteria. Now consider the following rearrangement of this series given by: \begin{align} S:=1+\frac{1}{3}-\frac{1}{2}-\frac{1}{4}+\frac{1}{5}+\frac{1}{7}-...+\frac{1}{4n-3}+\frac{1}{4n-1}-\frac{1}{4n-2}-\frac{1}{4n}+... \end{align} I want to see that this series converges aswell and has the same value $a$. I am stuck with this one. Does someone have a hint how to start this?   Edit: this not a duplicate to the question in the link below since I am asking on how to get the limit value of this series.


Can I use my own answer on my web site without attribution?

Upon answering a question on Stack Overflow, say I wanted to use my own answer in a blog post (or something similar) on my own personal site. Knowing that the Stack Exchange's content is  licensed and , how does that translate when I am the author reusing my content on my own site? To take it a step further: If I have an answer to a posted question published elsewhere, let's say to my own personal site again to avoid licensing confusion, that I feel applies to a question being asked on Stack Overflow and I copy paste it as an answer, who retains that license? Would I have to retroactively attribute Stack Overflow?


Why do we say that the Earth moves around the Sun?

In history we are taught that the Catholic Church was wrong, because the Sun does not move around the Earth, instead the Earth moves around the Sun.  But then in physics we learn that movement is relative, and it depends on the reference point that we choose.  Wouldn't the Sun (and the whole universe) move around the Earth if I place my reference point on Earth?  Was movement considered absolute in physics back then?


When I'm composing the answer I want to see the question somewhere near

I see two possible solutions:   Put the answering form immediately below the question (in the collapsed state by default) Put a copy of the question near the answering form.


If is work done by magnetic field is 0 then why does 2 magnets attract when kept together?

If 2 magnets are kept close to each other they attract then shouldn't it be considered as work done by magnetic field?


$x\sin x$ is a solution of $n$th order linear differential equation. Find minimum $n$

Let $y(x)=x\sin x$ be one of solution of $n^{th}$ order linear differential equation with constant coefficients. Find the minimum value of $n$.  I have no idea where how to approach this problem. In book the answer is $4$.


Edit marked as rejected by Community, but actually rolled into someone else's

I suggested , which was rejected by the Community user due to an edit conflict. However, when I looked at the post, I saw my edit there anyway. Looking at , it appears that the asker's edit in revision 2 had its edit summary comment replaced by mine, and my change rolled into it. I find it highly unlikely that the asker would have done both of those things by hand, and much more likely that the site's software caused this somehow. Is this something that the developers just need to fix, or is there something that someone involved didn't do right that caused this? (This is not a duplicate of , because in that question, the edits didn't end up going through, but in this one, it did, just attributed to the wrong person.)


What is wrong with the following Jennifer Lopez's pop song ?  My Love Don't Cost a Thing


"SHOWPLAN permission denied in database 'StackOverflow'." again

As has happened a  , I'm seeing SHOWPLAN permission denied in database 'StackOverflow'. when trying to get an execution plan. I'm guessing this is an artifact of the recent Denver test.    It's not just Stack Overflow, I'm seeing it for all other sites.


ScreenShot/PrintScreen doesn't work with menus dropped down!

Whenever I try to take a screen-shot (in my Ubuntu 12.04 box ) with the global menu, context menu for any window/file, it doesn't work. I don't seem to be able to take snapshots with menu dropped down. How do I get this fixed?  PS. The problem is in both Unity and Gnome3 environments.


Turning off Device Enrollment Notifications on MacBook Pro

I have purchased a MacBook Pro a year ago and after upgrading to Sierra started to receive notifications from a company that owned a laptop before. I have tried contacting Apple Service and the actual company, no luck so far. I have learned that I need to find two files: /System/Library/LaunchAgents/com.apple.ManagedClientAgent.enrollagent.plist /System/Library/LaunchDaemons/com.apple.ManagedClient.enroll.plist But I can't move them (and even create folders where they can be moved): /Library/LaunchAgentsDisabled and /Library/LaunchDaemonsDisabled Can anyone please help how I can turn off device enrollment notifications?


I wanted to know how the traffic is calculated if I get a backlink from a subdomain page. For example, a website corriere.it has over 20M organic traffic, but roma.corriere.it has 500K


How to execute several commands after each other with one request to the terminal (without using a file)?

I could (1) prepare a file with typed commands separated by end-line, (2) make it executable, (3) run it from a file-system manager or the terminal.  But this is ridiculous for not repeatable and every-time-other sets of commands.  Can I type those commands to the terminal in one request instead?  I don't know end-line character for the terminal - Ctrl, Shift or Alt with Enter doesn't work.


Tangent lines to ellipse from external point

I'm given an ellipse with the equation  $$\frac{x^2}{5^2} +\frac{y^2}{4^2} -1 = 0 $$  and I have to find the tangents to this ellipse  passing through a point $P(10, -8)$.


How does method_name= work under the hood?

I was hacking a simple implementation of linked lists in Ruby and I came across something very peculiar.  I created a List class with an attr_accessor to a first_node. Something like this:  class List   attr_accessor :first_node    # Some code here ... end   Then, while implementing the method delete_at I had the following error  linearly.rb:39:in `delete_at': undefined method `next' for nil:NilClass (NoMethodError)     from linearly.rb:81:in `<main>'  This is a piece of the method:  def delete_at(position)   if position == 0     deleted_node = first_node     first_node = first_node.next   # This is line 39.      return deleted_node   else     # More code here ...   I forgot to use the class variable @first_node and instead I used the reader method first_node. Then, I started wondering why first_node returns nil when using first_node= in the same line.   Does it set @first_node to nil before setting a new value?  Notice that this piece of code works just fine:   def delete_at(position)   if position == 0     deleted_node = first_node     first_node = deleted_node.next      return deleted_node   else     # Some code here ...   EDIT:  This is how I call the implementation:  list = List.new list.first_node = Node.new(1) list.first_node.next = Node.new(2) list.first_node.next.next = Node.new(3)  puts "Delete at 0" puts list.delete_at(0)


In Java, we sometimes do this:  int [] foo = new int [5]  How do you do this in C++? I've put this in and it gave me an error.


I'd like to install Ubuntu on my computer. I have a 500GB HDD with the following partitions: (at least what the Ubuntu installer shows):  / - Windows 7 (loader) - 100GB  - 400GB   I'd like to install Ubuntu to the 100GB partition as on the 400GB I have Windows. But I have problems with the following:   Whether I can set a swap particion without messing up my Windows. Which file system to set to the partition.   Please tell me what and how to do it in the installer.


What is the infinite sum of This alternating series?

I have encountered this alternating series and I want to know how we can prove that   $$\sum_{n=0}^\infty\frac{(-1)^{n+1}n^2}{n^{3}+1}=\frac{1}{3}-\frac{1}{3}\ln(2)+\frac{\pi}{3}\sinh\left(\pi\frac{\sqrt{3}}{2}\right)$$


Why a subject not in focus in the viewfinder of an analog camera is seen as two misaligned half circles, while in that of a digital camera is evenly blurred?


Are there Stack Exchanges in different languages?

I was wondering if there was, say, a "Spanish Stack Overflow." This would be the same as the Stack Overflow site, but people would ask and answer in Spanish. This way, the asker doesn't need a translator or knowledge of a foreign language to ask a question of the Stack Exchange community. Does something like this exist already, or could it be proposed in Area 51?  Note: This is NOT like Spanish Language Stack Exchange; questions there are about Spanish, but in English rather than about other topics, in Spanish.


$(a+b)^n=a^n+b^n$ in a field of characteristic $n$

There is a theorem : In a field such that its Characteristic $n$ is greater than zero , the equality $(a+b)^n=a^n+b^n$ is true.  Does anyone know how to prove it ?  Thanks.


Can I wash my Logitech K270 wireless keyboard?

I spilled coke on my Logitech K270 keyboard and now a couple of keys, once pressed, take minutes to retract.  The keyboard is touted as spill-proof. Can I pour water to clean it?


Where to get ubuntu linux kernel source package?

Where to get Ubuntu Linux kernel source package from? Not a Debian package. Is there any repository which has tar/bz2 package of complete kernel sources of every version release.


How to start Windows Explorer with home directory and libraries collapsed?

When opening Explorer in Windows 7, the directory tree on the left contains Libraries and the user's home directory. These two starts expanded/collapsed according to their expanded/collapsed state when Explorer was closed.  Is there a way to ensure the libraries and user's home directory always start in the collapsed state?  I generally start explorer with windows + E key combination.


Is there any way to fill earlier parts of an alias in when it's called?

Let's say I wish to create an alias for the command: find /path -not -path '*/\.*' Specifically, I'd like an alias nfind so that I can type nfind /my/path Setting: alias nfind='find /path -not -path '*/\.*'' this of course doesn't work, since I have no way to change the /path via calling the alias nfind. Is there a way I can make this happen?


Is there a faster way to remove a line (given a line number) from a file?

A related question is .  I often have to edit a large file by removing a few lines from the middle of it. I know which lines I wish to remove and I typically do the following:  sed "linenum1,linenum2 d" input.txt > input.temp   or in-line by adding the -i option. Since I know the line numbers, is there a command to avoid stream-editing and just remove the particular lines? input.txt can be as large as 50 GB.


I.ve this thing in php  $v = "test";   How do i pass this to javascript  I did like this    <script>   var t = <?php echo $v; ?>  </script>   I'm passing that t to URL  But ii says undefined


How to run a background task in PHP web application?

I want to run a background scheduler in my web application. This scheduler will check the current time and if it matches with the programmed time then it sends a E-mail. How can i create background Scheduler ?


Expected value of subset of variables in Bayesian setting

Assume we have $N$ random variables $X_1, \ldots, X_N$ with known (posterior) distributions that are easy to sample from. For simplicity, assume that I am interested in the expected value of the ten largest of these random variables. There will be some uncertainty surrounding this expected value as there is uncertainty with respect to the rank of a given $X_i$ in case the distributions of $X_1, \ldots, X_N$ overlap. I want to use simulation based methods. My approach is to simulate $M$ samples from the distributions of $X_1, \ldots, X_N$, where in each iteration, I construct a binary indicator of length $N$ indicating whether random variable $i$ is within the set of the ten largest samples or not. Averaging over these $M$ draws gives me the probability that random variable $i$ is member of the top ten group. Denote this probability as $\pi_i$. Define a binary random variable that indicates membership in the top ten group as $S_i$. $S_i$ follows a Bernoulli distribution s.t. $S_i \sim Ber(\pi_i)$. In a second step, I draw $L$ samples from the distribution of $S_i$ and from the distributions of $X_1, \ldots, X_N$. Given a draw of $S_i$, I can select the top ten out of the samples of $X_1, \ldots, X_N$ in each iteration and average the respective samples within the top ten group. I save this average, so the result after $L$ iterations will be the distribution of the average outcome within the top ten group, taking into account all relevant sources of uncertainty. My questions are: Is this simulation approach valid in general? From a Bayesian perspective, is this simulation valid or do I need to treat additional quantities (e.g. $S_i$ or $\pi_i$) as random variables that need a prior?


How do I get the version of an application from the command line?

I would like to know how to get the version information of an installed program that doesn't have the      --version or -version   method implemented.


Ok. So I defeated the wall of flesh. I created this a mushroom biome and the truffle won't move in. I have a mushroom door, mushroom work bench, a table, torches, and it's made out of mushroom grass. There are also mushroom monsters that I see in the underground mushroom biome and I see the giant mushrooms in the background. I know there is not a crimson or a corrupt biome nearby by because I cleansed them. My house is also the right heigth. The truffle keeps saying he wants to move in. Please help me figure out why the truffle won't move in.


Prove that the standard deviation is less than half the range

Taken from "An Introduction to Quantum Physics" by Stefanas Trachanas (Question 2.4).  I need to prove that for an arbitrary statistical distribution:  $$ \Delta A ≤ \frac{|a_{max}-a_{min}|}{2} $$  Where $a_{min}$ & $a_{max}$ are the minimum & maximum possible values of the distribution,respectively.  I have proved this for 2 special cases: The case in which the mean is at the centre of the range, & the case with only two possible outcomes. How do I prove the general case?


Amount of transitive relations on a finite set

In counting the amount of relations on finite sets, we can quite easily count the amount of reflexive and symmetric relations on a finite set. We just consider (in accordance with the definition of a relation on a set as a subset of the cartesian product of the set with itself) a grid with on the vertical axis all the elements of the set and on the horizontal axis all elements of the set. We can then mark the points on the grid which are elements of the relation.  Consider a set $S$ with $|S|=n$ for some $n\in\mathbb{N}$.  The amount of relations on this set is simply $|\mathcal{P}(S^2)|=2^{|S^2|}=2^{n^2}$.   The amount of reflexive relations $S$ can be found by considering that these relations on the grid are all the relations in which in any case the diagonal is in the relation. We see that $n$ pairs are already "chosen", so we can still choose for $n^2-n$ pairs whether or not they are in the relation while keeping the relation reflexive. So there are $2^{n^2-n}$ reflexive relations on $S$.  For the amount of symmetric relations we know that the pairs under the diagonal are in the relation if the corresponding ones above the diagonal are also in the relation. We have the freedom to choose any of the pairs above or on the diagonal of the grid, the amount of which is equal to $T_n=\frac{n(n+1)}{2}$. So there are $2^{\frac{n(n+1)}{2}}$ symmetric relations on $S$.  Relations both symmetric and reflexive are relations for which we can freely choose any pair above the diagonal of the grid. There are $T_{n-1}=\frac{n(n-1)}{2}$ pairs above the diagonal, so there are $2^{\frac{n(n-1)}{2}}$ relations both symmetric and reflexive on $S$.  Now I'm sorry for not getting the point sooner and please correct me if I am wrong about any of them, but I am wondering if there are similar simple expressions for the amount of antisymmetric and transitive relations on this set $S$. I have been told before it is very difficult to visualise transitive relations with the grid I suggested. For antisymmetric relations I think it means the diagonal is definitely in the relation and either a pair above the diagonal is in the relation or the corresponding pair below the diagonal, but not both. I don't really have any ideas as to how I could use these things to come up with a formula for the amount of relations.  Any help and/or comments are appreciated.  Thank you


I have two machines 1 iMac 2009 24” and one MacBook Pro 2017 touchbar. The iMac I cannot open at all as I erased everything from the Macintosh HD. I am trying to fix by using Catalina on the MacBook Pro to create a bootable USB to boot the iMac from.   The 2009 iMac had two partitions in its Harddrive, one for HD Mactintosh and one for BootCamp. I wanted to wipe everything so I shutdown the machine then started it while hitting CMD + R then I get the restore window and I choose restore Mac OS then it asks me to sign it to my apple store and I enter my App Store details but it gives this error This item is temporarily unavailable I wonder how I can get the macOS restored if anyone could please help as I am kinda stuck and don't know how to solve this.  I have downloaded the El Capitan .dmg file and erased a 32GB USB stick to macOS journaled but I don’t know how I can make it bootable from the dmg file? And then how I can use the bootable USB to install the macOS?


How to use an optimization solver to get t-stats and p-values for the estimates?

I calculate a data log likelihood (evaluated at a set of parameters to be estimated), and my task is to find the set of parameters that maximize my log likelihood.   My problem is: thought there are a bunch of matlab optimization algorithms that can give me the estimated parameter (like fminserch, patternsearch), they don't give the t-stats (or standard error) of each estimate....So if I want to check the robustness of the estimation, what should I do?   Thank you :)


Hey everyone I've been seeing this a lot lately and am trying to figure out why this error is thrown when querying the SOAP API directly. I've tried several very basic SOQL queries such as  SELECT Body FROM AssetFeed   Only to be met with the sObject type 'AssetFeed' is not supported. error.  The account that I'm currently querying is just a standard user who accepted permission from an app that was created by a Developer Account, so I'm wondering if it might be permissions from the user or permission from the app itself? Possibly because Developer accounts cannot use 95% of whats offered?  The WSDL used is a v27.0 generated Partner WSDL if that helps narrow it down.  I've noticed this in multiple standard objects, so I'm wondering what the trend really is? Seems like a good informational question for future googling of others?  Running describeGlobal()  Array (     [0] => AggregateResult     [1] => Attachment     [2] => ChatterActivity     [3] => CollaborationGroup     [4] => CollaborationGroupFeed     [5] => CollaborationGroupMember     [6] => CollaborationGroupMemberRequest     [7] => CollaborationInvitation     [8] => ContentDocument     [9] => ContentDocumentFeed     [10] => ContentDocumentHistory     [11] => ContentDocumentLink     [12] => ContentVersion     [13] => ContentVersionHistory     [14] => EntitySubscription     [15] => FeedComment     [16] => FeedItem     [17] => FeedLike     [18] => FeedTrackedChange     [19] => Group     [20] => GroupMember     [21] => HashtagDefinition     [22] => Name     [23] => TaskPriority     [24] => TaskStatus     [25] => User     [26] => UserFeed     [27] => UserPreference     [28] => UserRecordAccess     [29] => UserRole )   Where would all the rest of my SOAP SObjects be? This seems like a very thin list compared to the 295 SObjects advertised


I am trying to configure STM32F4 USART peripheral. I thought that USART Receiver pin(RX) must be programmed as Alternate function to USART works correctly and then the data is present on the I/O pin can moves into the USART Receiver Shift register. I mean that according to the following pictures taken from the STM32F4 Reference manual, when we do configure a pin as Alternate function it gives a way for the data to moves into the Alternate function input(here it is Receiver shift register) but when that pin is configured as Floating input (second picture) the data on that pin is just sampled into the input data register.   So logically i think that USART can't do it's job correctly when Receiver pin is configured as Floating input. but incredibly it does work in a correct way and i dont know why?! The same Problem has been discussed here :  But i couldn't find my answer there. Edited: Ambiguous point is that however in Floating input mode the data will also be sent to the connected Alternate functions But it's important to specify which peripheral this data will be sent to. When the microcontroller starts up from Reset mode, Reset values of almost all Registers is 0 so for instance pin 7 by default is connected to AF0 which that isn't for USART periph. So if we select Floating input mode for that pin and don't determine which alternate function we want to send the data, then the data might be sent to the wrong peripheral instead of USART receiver shift register. But incredibly without determining the peripheral which we want to select as our Alternate function, USART does the work correctly.  Actually my question is WHY does USART work correctly in this way (without determining The actual Alternate function)?


Refer to number 6. This is the one I'm stuck on. So angular momentum is conserved right, so initial angular momentum is equal to final angular momentum. Initial is 7.87 so final must be 7.87, right? And so average torque is just change in angular momentum / change in time, so 0/7=0. What am I doing wrong?


Howto change biblatex bibliography style for the label

How do I change the style of the literature labels in the bibliography?   I'm searching about a few hours now with no luck, so maybe anyone here can help! Below you see my example and at the bottom of the post I show you what I want to get. I read a lot about the \DeclareFieldFormat method, but it seems that this one is not working for the labels. I tried it for the book title at this works fine \DeclareFieldFormat[book]{title}{\textbf{#1}}. Isn't there an equivalent for the labels?  Example document file:  \documentclass[11pt,a4paper]{scrbook}  \usepackage[ngerman]{babel} \usepackage[babel,german=quotes]{csquotes} \usepackage[breaklinks=true]{hyperref} \usepackage[ style=authoryear, backend=bibtex, ]{biblatex} \bibliography{literature}  \renewcommand*{\labelnamepunct}{\addcolon\space} \DeclareFieldFormat[book]{labelname}{\textbf{#1}}  \begin{document}  \cite{apple2012staticlibrary} \cite{fowler2003patterns}  \printbibliography  \end{document}   Bibliography file:  @techreport{apple2012staticlibrary,     Author = {Apple},     Date-Added = {2013-07-18 07:52:40 +0000},     Date-Modified = {2013-07-20 11:39:36 +0000},     Institution = {Apple Inc.},     Publisher = {Apple Inc.},     Title = {Using Static Libraries in iOS},     Year = {2012}}  @book{fowler2003patterns,     Address = {Heidelberg, M{\"u}nchen, Landsberg, Frechen, Hamburg},     Author = {Martin Fowler},     Date-Added = {2013-07-17 09:26:03 +0000},     Date-Modified = {2013-07-23 06:49:25 +0000},     Publisher = {mitp-Verlag},     Series = {Software-Engineering},     Title = {Patterns f{\"u}r Enterprise-Application-Architekturen},     Year = {2003}}   This is how it looks like (Ignore the ISBN field. Its just an older screenshot):   And this is how I want it to look like (with the bold label):  Apple (2012): Using Static Libraries in iOS. Techn. Ber. Apple Inc.  Fowler, Martin (2003): Patterns für Enterprise-Application-Architekturen. Software-Engineering. Heidelberg, München, Landsberg, Frechen, Hamburg: mitp-Verlag.


“5-min” video vs “5 min” video vs “5min” video

Example:     Paul and Jake discuss the Frame Timing API in this 5-min video: …   Which character (if any) should be put between the number and the word “min”?


PhpStorm tells me that FILTER_SANITIZE_MAGIC_QUOTES is deprecated. What filter should be used in its stead? I'm using it to sanitise data before it is used to create MariaDB queries.


I'm asking only because or i'm only asking because- what would be the proper or better sounding version

I seem to be excessively over analyzing the superior manner in which the sentence ought to begin. The proceeding phrases are what I need advice with, so as to decide the proper wording, to initiate the sentence opening. I'm simply asking what would be most applicable or appropriate sounding version of the two...


Show that with probability one the events cease to occur ultimately under certain conditions

Let $A_n$ be a sequence of independent events with $$lim_{n \to \infty}P(A_n)=0.$$ Suppose that  $$\sum_{n=1}^{\infty}P(A_n^c \cap A_{n+1}) < \infty.$$ Will the events $A_n$ cease to occur eventually with probability one?  I think that the question is asking to show that  $$P(A_n\ i.o.)=0$$ And I tried to prove that $$\sum_{n=1}^{\infty}P(A_n)<\infty$$ So that I can use the Borel-Cantelli Lemma.  But I did not get nowhere. I am kind of confused about all these operations includes limits, sets, and interplays between them, as well as the $limsup$ and $liminf$ stuff. Hope someone could help me.


What's the purpose of an array of same VALUE capacitors?

I'm looking at the schematic of the AM3354 EVM and I don't know why I see so many of the same value capacitors used in parallel and typically around the processor or memory.   I understand that different capacitors will have different self resonant frequencies and perhaps that is advantageous for noise filtering but why so many of the same value? Isn't one sufficient?   This question is based around the same value of components not simply combining different value capacitors into one larger capacitance part.


Reason for the current trend to use «she» as the gender-neutral pronoun?

There are some questions on gender-neutral pronouns both  and on .  User Christine Letts :     In academia, there is currently a   movement toward using the feminine   pronoun at all times.   I wonder why that is. I came across several examples on papers I read, but the only one I can remember at the moment is a book: Seth Godin's . While some might not be comfortable labeling it as part of academia, it suits my point perfectly. Every time he refers to a person, he uses the feminine pronoun.  User Senseful  the following, potentially identifying affirmative action as the precursor for this trend.     I remember reading somewhere that it   was recommended to use the opposite of   what most people stereotype the   profession as. So, for example, when   talking about a chiropractor, you   would use "her", and when talking   about a secretary, you would use   "his".   So, where do you think this trend comes from?


why does my world property look diffent from this one?

Someone was helping me with ambient light and showed me this from 2.79 and mine looks like the second picture. Why?


Is the limit of reciprocals always the reciprocal of the limit?

How to prove that for L not $0$, if the limit as $x$ goes to infinity of $f(x)$ is $L$, then the limit as $x$ goes to infinity of $\frac{1}{f(x)}=\frac{1}{L}$  I am unsure how to present this proof, and furthermore I am unsure of its validity:


Any way to see how many questions with certain tag(s) are in the close vote queue?

I just recently started using the filtering options for the close vote review queue. I really like it.  I was searching the data explorer to see if there was currently any methods to see how many questions are in the close vote review queue for a certain tag, but wasn't able to find anything.  I think it would be useful to me and others, if not at least just very interesting to see which tag(s) have the most or least questions in the close vote review queue.  For example, if say a question is tagged with   and  , I would like to see how many of these questions are in the close vote queue.  So that if I choose to filter by questions containing both those tags, I can then determine how much progress I'm making at clearing those up, and hopefully get them down to 0 if realistically possible. Plus I'd have a better sense of accomplishing something, instead of just always seeing the close vote review queue being increased no matter what we do. On a sidenote: I do think that at least trusted users or even 10kers should get 150 or so close votes per day.


Diagonal line in table header when header is tall

I've been trying to get a diagonally-split table header using the diagbox package, but I have a problem.  Here's a working sample that shows the problem:      \documentclass[12pt, a4paper, twoside]{article}   \usepackage{diagbox} %table split headers \usepackage{longtable}  \usepackage{array} \usepackage{rotating}  \newcommand{\tabred}{-4pt} \newcommand*\rot{\rotatebox{90}}  \begin{document}  \begin{longtable}{     | l<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}      | >{\hspace{\tabred}}c<{\hspace{\tabred}}     |}  \hline  \diagbox[dir=NW]{Feature}{Tool}  & %THIS IS THE PROBLEM!  \rot{Tool Alpha}    &  \rot{Tool Delta}    &  \rot{Tool Gamma}    &  \rot{Tool Theta} &  \rot{Tool Upsilon} &  \rot{\textbf{Tool X (our proposal) }}\\  %\midrule \hline  Feature A - Fooing the Bar  & NO    & NO    & NO    & NO    & OK    & OK\\ Feature B - Barring the Foo & OK    & NO    & OK    & NO    & NO    & OK\\ \hline \end{longtable}  \end{document}   The problem is that, since I rotate the headers, they are very tall. As you can see from the image below, this ruins the alignment of the diagonal line:    As you can see, there are two problems: the north-west end of the diagonal line doesn't touch the north-west corner of the box, and the south-east end of the diagonal line doesn't touch the south-east corner.  With the answer posted here:  I've been able to use \rule to fix one of the angles, but never both. No matter what I try, the spacing screws up.  Any ideas?


Should answers by new users who seem to have signed up just to recommend a site/product multiple times be flagged as spam?

Every now and then, when reviewing the New answers to old questions list, I find answers recommending a third-party tool or site.   They're probably not the best kind of answer but in the context of the question it could actually be relevant and be contributing something.  But when we see the same user posting several recommendations for the same product, and the specific user just signed up, maybe something spammy might be happening (or it could be an enthusiasthic happy user/customer).  Seems like there are users who (apparently of course) just sign up to recommend a product or tool. Sometimes there is more than one new user recommending the same product around.  Should we flag those answers as spam?


Do players know if a hit from a monster is a critical hit?

There are a few different abilities that PCs can get where once they are hit with an attack they can decide to use to potentially turn the hit into a miss. Examples include the spell Shield or a Cavalier fighter's Warding Maneuver feature. The way our group currently plays all the DM's rolls are hidden from us and they convey whether attacks hits or misses to us. In the case of a hit the player informally has until the DM rolls damage to decide whether to use a feature that might change the outcome. While the players are aware of when an attack is a hit, are they aware if the attack is a critical hit? If so they would know that using such features would be a waste of resources. This would also apply to rare features that can force a reroll after an attack roll is already made such as with the Rune Knight's Runic Shield feature. If a player knows that an attack is a critical hit they would be more inclined to use such features.


How to effectively save last 7 days statistics in SQL database?

I need to save statistics from past 7 days. But tomorrow I need to remove or replace data that was saving 8 days ago. I was thinking about having a table with 8 columns (name + 7 days) and every night remove last one and create new but it sound bad. What is the best way to do this?


Why do many uC have more then one I2C interfaces?

On I2C buses you can hock up 112 devices. So why do so many microcontrollers have up to four I2C ports, when you could just operate enough devices for most applications on one I2C interface?


How to paste today's date *and initials* with keyboard shortcut?

This question will be asked and answered, thanks to the contributors to  previous question.  I am on High Sierra OS X.  I want to be able to hit some keyboard shortcut and then have today's date and my initials inserted into text. This will be a date stamp used when making entries into a CRM database.


So, this question has been bugging me a lot, I used to have a few lovely little toys (well, not so much toys as a pentium pro and a really old Intel 80386DX microprocessor) What I noticed is that when the CPU's are under load they generate a most delicious noise which reminded me of when I used those computers for actual things (the 80386 had DOS 6.2 at one time and I ran a small unix server on it a few years later, the pentium ran windows 95 and then later windows 98+ and even later I somehow barely got xp running on it), I almost dare say it's nostalgia.  Anyway, that noise made me curious, what causes it? My first hypothesis for this rumbling/humming sound is the fan, so I tried removing every last fan, the noise didn't stop, it was actually easier to hear when the whirring of the fans wasn't there, I then spent hours testing each piece of hardware and came to the conclusion that the CPU itself was making the noise and then decided that I was happy with my conclusion for then, I recently remembered it and I got curious as to what generates it.  I don't own those machines anymore (alas I had to get rid of them due to moving) but I have observed that newer CPU's make the same noise, just a lot fainter and more subtle, so I do think it has something to do with the underlying architecture.  Anyway, before my rambling carries off too far... What causes the noise and is there any correct terminology for it? These questions are derived from a few hours on google and getting nothing but people asking silly questions such as "Why is my hdd ticking?" or "Why is my CPU producing a high pitch noise?" (the latter is closer but not what I am looking for as the noise is low pitch and quite distinct, if you've heard it you should know what I'm talking about)  I want to know this for a couple of reasons, curiosity is one but I also want to utilize this sound effect in a project of mine.  Now, some of you may point out that CPU's have no movable parts and are thus incapable of generating noise, then what could possible causes be? I tried removing everything redundant from those machines and the sound prevailed, the only things I didn't remove or replace was the mobo's and the cpu's themselves (because finding such old hardware proved harder than expected. oh and this part is what really sparked my curiosity as to what was generating the sound as the fans were silent when just powered on, and the machine kept making noise without them (I ran them at short 1 minute intervals))


Title is fairly self-explanatory. For example, for $y=27$, $x$ would be $3$. Specifically I was trying to find $x$ given $y = 10^{100}$, but I'd like to know how to solve it for any value of $y$.


Least common multiple of $1,2,\ldots,2n+1$

Here's a problem that I heard: Show that $lcm(1,2,\ldots,2n+1)\geq4^n$.  If you assume the prime number theorem then it's not too hard to show that $lcm(1,2,\ldots,2n+1)$ is eventually larger than $4^n$. The hard part is making this effective for small values of $n$. Also, I've been told that you can prove this without the prime number theorem.


I always thought water sources were called taps in kitchens, bathrooms etc, but a Google search only returned outdoor taps.  So my question is, what are indoor taps really called? Like this one:


Using array columns as arguments of a macro

I am creating a table using array, and I want one of my columns to be used as the argument of xrightarrow as shown below. To make the code cleaner, I want to avoid having to write xrightarrow for each row of the table. I tried using the functionality of the array package to make the second column the argument of xrightarrow (my feeble attempts are commented out below). Is there any way to make this work, or do I need to repeat the xrightarrow for each row of the table?  \documentclass{article}     \usepackage{amsmath}     \usepackage{array}  \begin{document}  \[     \begin{array}{l@{\qquad}c@{\qquad}l}         Y = \alpha X^{\beta}         & \xrightarrow{X' = \log(X) , Y' = \log(Y)}         & Y' = \log(\alpha) + \beta X' \\         Y = \alpha \exp(\beta X)         & \xrightarrow{Y' = \log(Y)}         & Y' = \log(\alpha) + \beta X     \end{array} \]  %\[ %   \begin{array}{l@{\qquad}>{\xrightarrow}c@{\qquad}l} %       Y = \alpha X^{\beta} %       & X' = \log(X) , Y' = \log(Y) %       & Y' = \log(\alpha) + \beta X' \\ %       Y = \alpha \exp(\beta X) %       & Y' = \log(Y) %       & Y' = \log(\alpha) + \beta X %   \end{array} %\] % %\[ %   \begin{array}{l@{\qquad}>{\xrightarrow{}c<{}}@{\qquad}l} %       Y = \alpha X^{\beta} %       & X' = \log(X) , Y' = \log(Y) %       & Y' = \log(\alpha) + \beta X' \\ %       Y = \alpha \exp(\beta X) %       & Y' = \log(Y) %       & Y' = \log(\alpha) + \beta X %   \end{array} %\]  \end{document}


Is there a way to call an object's overridden base class methods?

Given a pointer to a derived object, which has overridden some method virtual void moo(), is there a way to call the base's moo() method? One way is to create a sliced base class object from the derived object, but that would involve copying: #include <iostream>  class A {     public: virtual void moo() { std::cout << "moo from A\n"; } };  class B final : public A {     public: void moo() override final { std::cout << "moo from B\n"; }; };  int main() {     A* a_ptr = new B; // could point to any A or A-derived object.      A a(*a_ptr); // is there a way to get A::moo without doing this?     a.moo(); // moo from A of course, but would be cooler without the copy above }  Why would I wanna do that you ask? So glad that you ask... not, because now I have to explain everything to you. Well A's virtual void moo() is actually more like std::string serialize(), which gives A's data members serialized into a std::string. Now when you have a big std::vector<A*> pointing to all sorts of derived objects and only the data from the base objects are needed (to be sent over network), it'd be nice to get only A::moos, although those pointers in that vector point to all sorts of moos. (I'm aware of the possibility to 'simply' put a second void moo2() into A, that does not get overridden. But I'd also like to know if there's a third or fourth alternative.)


Let $A$ be the set of all those points of plane $\mathbb{R} ^2$ in which both coordinates are rational or both are irrational. Is $A$ path connected?


Confusion in proof that primes $p = 4k + 1$ are uniquely the sums of two squares

I'm reading a proof in my number theory textbook that all primes of the form $p = 4k+1$ are uniquely the sum of two squares. I'm stuck right at the beginning of the proof, where they say:  To establish the assertion, suppose that $$ p = a^2 + b^2 = c^2 + d^2 $$ where $a,b,c,d$ are all positive integers. Then $$ a^2 d^2 - b^2 c^2 = p(d^2 - b^2). $$  Perhaps I'm just missing something obvious, but I can't figure out how they managed to conclude that $a^2 d^2 - b^2 c^2 = p(d^2 - b^2).$ Please advise.


I just finished reading Silverman and Tate's Rational Points on Elliptic Curves and thought it was very interesting.   Could any of you point me to some more references (ex. books, articles) on elliptic curves? Someone suggested Silverman's Arithmetic of Elliptic Curves, but I don't have any background in algebraic geometry, so I'm not sure how well I would understand it (going to start studying commutative algebra - does that help?). Thank you!


Let $p$ be prime and $(\frac{-3}p)=1$. Prove that $p$ is of the form $p=a^2+3b^2$

Let $p$ be prime and $(\frac{-3}p)=1$, where $(\frac{-3}p)$ is Legendre symbol. Prove that $p$ is of the form $p=a^2+3b^2$.   My progress:  $(\frac{-3}p)=1 \Rightarrow$ $(\frac{-3}p)=(\frac{-1}p)(\frac{3}p)=(-1)^{\frac{p-1}2}(-1)^{\lfloor\frac{p+1}6\rfloor}=1 \Rightarrow$ $\frac{p-1}2+\lfloor\frac{p+1}6\rfloor=2k$  I'm stuck here. This is probably not the way to prove that.  Also tried this way:  $(\frac{-3}p)=1$, thus $-3\equiv x^2\pmod{p} \Rightarrow$ $p|x^2+3 \Rightarrow$ $x^2+3=p\cdot k$ stuck here too.  Any help would be appreciated.


What path can I use to specify content in beamer theme styles?

The author of this  posted the source on github, but as the commits state, the background image was thrown in later and not referenced in the style files.  I added a global background template to the main style file, but using ./ as the relative path doesn't work. Is there a relative path for CURRENT_THEME that I can use to specify it? Neither the Beamer manual nor any existing questions/answers I found go into path issues about this.


How to install latest version of R on Ubuntu 12.04 LTS?

I am not able to download the latest R version on my Dell Vostro 14 3000 Series laptop running on Ubuntu 12.04 LTS.   I typed in the standard commands on Terminal:  sudo apt-get update  sudo apt-get install r-base  sudo apt-get install r-base-dev   But the net result is R 2.14.1 getting installed instead of R 3.2.0 (latest version) or even 3.1.1  I'm a Linux / Ubuntu newb, so please do guide keeping that in mind. Cheers!


If there is an automorphism between elements in a ring, why does this mean that the quotient ring over certain ideals are isomorphic?

I am looking at the first answer to this question:  Why does the existence of an automorphism between $x$ and $x+1$ imply that the quotient rings are isomorphic? I understand that when you substitute $x$ with $x+1$ in the original expression you get $$(x+1)^3 + x+1 +1 = x^3 + 3 x^2 + 4 x + 3 = x^3 + x^2 +1$$ in $\mathbb{Z}_2[x]$, but I don't understand the connection to the quotient ring. I am trying to apply the logic to a similar question, to show that $$\mathbb{Z}_2[x] / \langle x^2 \rangle \cong \mathbb{Z}_2[x]/\langle x^2-1\rangle$$ But I cannot convince myself why this automorphism leads to the conclusion that the quotient rings are isomorphic.


How do you make a file not have a default program that opens it?

I have .java files that right now open with a default program that is notepad++, but I don't want a default program to open all my Java files, I want to choose every time.  How would I go about making it not have a default opening program?


Can you bind a DataTrigger to an Attached Property?

In WPF, is it possible for a DataTrigger to bind to an attached property?  I essentially want to use a converter on an attached property to provide a style when a particular validation rule has been broken. I am using markup like the following:  <DataTrigger Binding="{Binding Path=Validation.Errors,                         RelativeSource={RelativeSource Self},                         Converter={StaticResource RequiredToBoolConverter}}"                         Value="True">   <Setter Property="Background" Value="LightGreen" /> </DataTrigger>   However, when this runs, I get the following:     System.Windows.Data Error: 39 :   BindingExpression path error:   'Validation' property not found on   'object' ''TextBox' (Name='')'.   BindingExpression:Path=Validation.Errors;   DataItem='TextBox' (Name=''); target   element is 'TextBox' (Name=''); target   property is 'NoTarget' (type 'Object')   If I change my DataTrigger binding path to "Text", I do not get the databinding error (but of course it does not provide the behaviour I am seeking).


How do I remove a question I asked, when it has an upvoted answer?

Is there a way to delete a question after it's been answered, and the answer has an upvote?  Imagine that I have asked a question, that is later considered by me or the community as not useful and/or too specific. Or it gets a lot of downvotes for some reason. While it is not closed or flagged as a duplicate yet, someone could still answered it. Once answered, I cannot delete it any longer.  Is there a way to delete such question? Without having moderator privileges (to delete at will), is casting close votes the only way? I think I should have more control over the fate my own questions.  (On another example, I had a self-answered question where I was able to delete it only after unaccepting my own answer.)


Consider the sentence - "A fifty year old man is walking in the garden." Shouldn't it be 'fifty years old'  or  'fifty-year old' or something else maybe? Is the original usage correct?


Have to run rmmod b43 ; sudo rmmod bcma ; sudo rmmod wl ; sudo modprobe wl after restart?

I have a Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01) and unless I run rmmod b43 ; sudo rmmod bcma ; sudo rmmod wl ; sudo modprobe wl after restart, the wireless device isn't available in network devices. Is there a way of making it work without having to modprobe the device issues?


Must declare the scalar variable "@VarName"

Could anyone shed some light on this error for me? To a beginner of course. This will probably be no more than a simple fix for someone else.  I'm trying to read in the Product to be used in the where clause.  alter proc Proc1 @ProductID int as go select ProductName from Products where ProductID = @ProductID


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


How to understand the function $o(h) + o(h) = o(h)$?

On page 150 of the book Introduction to Mathematical Statistics, there's the following passage:     Let the symbol $o(h)$ represent any function such that $lim_{h→0}[o(h)/h] = 0;$ for example, $h^2 = o(h)$ and $o(h) + o(h) = o(h)$.   I can understand how $h^2 = o(h)$ fits the description. But I couldn't understand the function $o(h) + o(h) = o(h)$.


Can HDD Platters be interchanged between different HDDs

Can HDD platters theoretically be interchanged that one could recover data from a HDD in which something else might be damaged? I am interested if it is technically possible, whichever effort is needed for that. This might also be of interest for forensic research.


How to install Windows 7 on Mac mini server?

Previously I installed Windows 7 on a Macbook Air without problems using Boot Camp Assistant and the excellent directions .  Now I am trying to install Windows 7 on a Mac mini server and I encounter error with every approach I take. I already have a bootable USB disk with Windows 7 installer.  First I tried to install Windows 7 directly booting the installer. Installer refused to continue displaying an error mentioning something about GPT drive.  Second I tried to install using Boot Camp, but it does not exist on Mac mini servers!  So I copied the Boot Camp Assistant app from Macbook Air, and selected the option "Download the Windows Support software for this mac". It was not able to find and download anything.  I thought I could handle the driver issues later, I used Boot Camp Assistant to make the 500 GB harddisk Windows installable. Then I booted into the installer, selected BOOTCAMP partition and formatted it. Installer did not continue displaying 0x80300024        error.  I run out of ideas and am rather frustrated. Are there any simple instructions on how to install Windows 7 on Mac mini server? Or how can I solve my problem and install?


How do I remount a filesystem as read/write?

I'm trying to mount an hfsplus filesystem in a Xubuntu 12.04 VM (kernel version 3.2.0-23-generic) but when I type mount -o remount,rw /dev/sdb3 in command line it returns not mounted or bad option. Any help would be appreciated.


What equation could you use to model the shape of a thread when held at 2 ends?

If you were to hold a string at both ends what shape would the string take(in earth's gravity). Obviously this depends on the length of string and the distance you hold the 2 ends apart so let's say that you can only change the distance of the ends from one another on a straight line parallel to the ground. What equation could you use to predict the shape of the string at any given length(of the string) and distance(of the ends)?


If every irreducible representation of a finite group has dimension $1$, why must the group be abelian?

Suppose $G$ is a group and that every irreducible representation of $G$ has dimension $1$. Why does this mean that $G$ is abelian?  The number of $1$-dimensional representations of $G$ is given by $|G/G'|$, where $G'$ is the derived subgroup of $G$. So if every irreducible representation of $G$ has degree $1$, then the number of conjugacy classes of $G$ is equal to $|G/G'|$. I can't see how to conclude that $G$ is abelian (or if this is the right approach).  Any help appreciated. Thanks


Text formatting enhancements on Facebook

Does Facebook have any text formatting enhancements like ? While writing a comment or status update, can I use linked texts or @-referrals? Or is it just like Notepad?


Let X be a compact CW-complex. The infinite cartesian product $Y=\prod_{n\in\mathbb{N}}X$  is a compact topological space, and as CW-complex It should have a finite number of cells. But in the CW-decomposition of Y given in  infinite cells appear. What is happening?


Describe the quotient field of polynomials with integral coefficients

The exercise is given as follows "If we take the integral domain $\mathfrak{D}$ consisting of all polynomials $a_nx^n+...+a_1x+a_0$ with integral coefficients, under ordinary addition and multiplication of polynomials, describe the quotient field of $\mathfrak{D}$" Now here is what I did until the moment, first let $\mathfrak{D} = (\mathbb{Z}[x], +_d,\times_d)$, where $\mathbb{Z}[x]$ is the set of all polynomials with coefficients in $\mathbb{Z}$ and $+_d$, $\times_d$ are the addition and multiplication of polynomials. Let $W = \mathbb{Z}[x]\times\mathbb{Z}[x] - \{0_d\}$, where $0_d$ is the zero polynomial in $\mathbb{Z}[x]$, then for any $(x,y)$ and $(u,v)$ in $W$ we establish the relation $\sim$ such that $(x,y)\sim(u,v) \Leftrightarrow x \times_d v = y \times_d u$ Then we let $F = \{[(x,y)]_\sim : (x,y) \in W\}$, that is, $F$ is the set of all equivalence classes given by the relation $\sim$ on $W$, now for any $[(x,y)]$ and $[(u,v)]$ in $F$ we can define $[(x,y)] +_F [(u,v)] = [((x \times_d v) + (y \times_d u), y \times_d v)]$  and $[(x,y)] \times_F [(u,v)] = [(x \times_d u, y \times_d v)]$ Then $\mathfrak{F} = (F, +_F, \times_F)$ form a field, which is the quotiet field of $\mathfrak{D}$. I already know that following those steps from a given integral domain, I will have a field, but I think the author of the book want something more, I tried to think about this structure but I just can see obvious thing which is clearly by definition, for example, the elements of our set $W$ is ordered pairs of polynomials where the second is different from zero, and the elements of $F$ are sets of elements of $W$. Well, the next question ask me to show that the quotient field of a field is isomorphic with the field itself, maybe the field $\mathfrak{F}$ on the previous question which is the topic of my post is isomorphic with some specific kind of structures, but I dont know yet, I got stucked because the author asked to 'describe' the quotient field, its different from all other his questions where he ask to prove/show something. There is a way to properly describe this specific field? Any property about this specific field will be appreciated also.


How dangerous and common is "leaking electricity" in Mac Book pro laptops

I recently found out that my MacBookPro11,4 is "leaking electricity" somewhere. At first it seemed like a minor tingle. Then i tried to see if it gets worse if i touched a good conductor (a radiator) and the laptop at the same time. It got a lot worse. From tingle to a continuous surge that for some could be quite unbearable.   How "normal" is this ? How dangerous is this to people? How damaging is this to the laptop itself? What exactly causes this? Is fixing this covered by standard warranty?


I was wondering if there is a principled way to figure out how many samples to discard during the MH-MCMC burn-in stage. So, as I understand it, the initial samples can introduce bias in the computation of expectation in the estimated posterior distribution especially if they are really far from the mean.   I was wondering, say I do a MAP estimation and try to find some local mode of the distribution to initialise my MH-MCMC. Would that mean I do not have to do the burn in (assuming this mode is in some high density region of the distribution)?


Why does `find` in Linux skip expected results when `-o` is used?

Why in Linux (Debian 8)  touch 1.cpp 1.h find . -name "*.cpp" -o -name "*.h" -exec echo {} \;   outputs only 1.h while  find . -name "*.cpp" -o -name "*.h"   outputs both? Is it a bug or feature?


I have 4TB hard drive, how to use it under both OSX, windows and linux?

How to format it so that it can be used in Ubuntu, windows and OSX?  Fat32? I have rull out NTFS as an option.


I have some values (:a , :a , :b , :c , :f , :f) which I want to store in a unique index based Data structure, which I can later iterate over to get my values.  Can any one please let me know which is the simplest way ?  E.g   :a :a :b :c :f :f   LATER,  Iterate on the DATA STRUCTURE based upon, the INDEX, to get my values  Thanks in advance


I have two e-bike batteries. One of which i am using to power my ESP32. Now i want to switch to other battery when my batt-1 is low. I am switching battery using relay. But doing so, I suspecting i might reset esp32 and hence state will be lost. I need solution around this problem.  P.S. Can not give external power supply to esp32


Why we can't differentiate both sides of a polynomial equation?

Suppose we had the equation below and we are going to differentiate it both sides: \begin{align} &2x^2-x=1\\ &4x-1=0\\ &4=0 \end{align}  This problem doesn't seems to happens with other equation like $\ln x =1$ or $\sin x = 0$, we can keep differentiating these two without getting "$4=0$", for example. This why I asked about polynomials.  PS: I'm not trying to solve any of these equations by differentiating then. But differentiation or integration helps and solving equations?  I remember that sometimes to solve trigonometry equtions like $\sin x = \cos x$ we had to square both side so we could use the identity $\sin^2x + \cos^2x =1$. Even thought squaring appears to make it worse because we have a new root.


Dual boot after ubuntu install not working - NO EFI and different hard drive

Edit: I'm trying to install Ubuntu 16.04 in a different hard drive than Windows, but grub is not loading after install.  I found a lot of topics relating windows 10 in EFI mode and Ubuntu, but my windows 10 is installed in legacy mode. Checking windows 10 disk management I don't have an EFI partition, so that confirms that I'm in legacy mode (double checked in BIOS and in Windows info).   I followed  to install Ubuntu.  I adapted the tutorial to install Ubuntu in a different hard drive. I installed Ubuntu in /dev/sdb2 and 3 (the partitions that I created: root and home) and grub was installed in /dev/sdb.  Windows 10 is installed in /dev/sda1, and windows boot loader is installed in /dev/sda.  After Ubuntu is finished and I reboot, grub is never loaded. I even tried changing boot order BIOS order to first look into Ubuntu HDD, but nothing happens and windows is loaded.  Any clues on what might be happening?  Edit2: I'm running a desktop with an asrock mobo, 1 ssd and 1 hdd. Windows is installed in a M.2 ssd and Ubuntu is installed in the hdd


Convert string of datetime to datetime object

I have a list of datetimes that were imported as strings: datetimes = ['datetime.datetime(2021, 2, 16, 12, 39, 54, 30886)',  'datetime.datetime(2021, 2, 16, 12, 40, 5, 238783)' ... ]  How can I convert the string into a datetime object?


I need someone to review the following proof to find the range of tan $\theta$, whether it is acceptable or not: Starting with |cos$\theta|\le$ 1 Square both sides: |cos$\theta|^2\le 1^2$ Simplify:  $cos^2\theta\le 1$ Use reciprocal property for inequality: $\frac{1}{cos^2\theta}\ge\frac{1}{1}$  Use reciprocal identity: $sec^2\theta\ge1$  Use Pythagorean identity: $1+tan^2\theta\ge1$  Simplify:  $tan^2\theta\ge 0$ Since the square of any real number is always greater or equal to 0, it follows that the range of tan $\theta$ is the set of all real numbers.  *************************************************************************** I need someone to review the following proof whether it is acceptable or not. Using the rectangular coordinates definition of $\tan \theta=\frac{y}{x}$ where $\theta$ is in standard  position and (x,y) is a point on the terminal side, tan $\theta=\frac{y}{x}$   =$\frac{y-0}{x-0}$    = Slope of the terminal side (The terminal side starts from the origin) Since the slope of a straight line is the set of all real numbers, it follows that the range of tan θ is the set of all real numbers.


Is there any difference in these two ways of creating object methods?

Is there any difference in the way these two objects create their methods? Are there performance differences? What's the difference here, if any?  Method 1:  var Point = function(x, y, z) {     this.x = x;     this.y = y;     this.z = z;      this.add = function(point) {         this.x += point.x;         this.y += point.y;         this.z += point.z;     };      this.sub = function(point) {         this.x -= point.x;         this.y -= point.y;         this.z -= point.z;     }; };   Method 2:  var Point = function(x, y, z) {     this.x = x;     this.y = y;     this.z = z; };  Point.prototype.add = function(point) {     this.x += point.x;     this.y += point.y;     this.z += point.z; };  Point.prototype.sub = function(point) {     this.x -= point.x;     this.y -= point.y;     this.z -= point.z; };


What's the nearest substitute for a function pointer in Java?

I have a method that's about ten lines of code.  I want to create more methods that do exactly the same thing, except for a small calculation that's going to change one line of code.  This is a perfect application for passing in a function pointer to replace that one line, but Java doesn't have function pointers.  What's my best alternative?


SQL to find the number of distinct values in a column

I can select all the distinct values in a column in the following ways:   SELECT DISTINCT column_name FROM table_name; SELECT column_name FROM table_name GROUP BY column_name;   But how do I get the row count from that query? Is a subquery required?


How can I convey a sensation of speed in space?

I'm making a game where you see a spaceship (in 3rd person) travelling at high-speed between planets (it takes 2-3 seconds move between them).  What effect could I use to convey the effect of extreme speed? I already know about the usual effects, change in FOV, white lines around the subjects, etc..   I'm asking about some things that are more space-like, I mean even if it's not how it would be perceived in real physics, I need it to look like it's fast and it's in space.  Don't hesitate to ask for clarification, my English is nowhere near being perfect, maybe I didn't convey my thought perfectly.


How to set up my wireless card when there is no official driver for BCM43142?

I managed to download a driver on page   I also tried to install bcmwl-kernel-source and I succeeded.  I'm now able to access internet through wireless.  But my problem is quite different from other BCM43142 users.I get offline every 3 minutes on average,but I just don't know what to do.  You know,it's really annoying that when I was typing this ,I got disconnected again.  My experience before tells me that perhaps the problem comes from the incorrect driver,but in fact I can't find a correct driver....  I googled,but there was no useful information.  Please help.Thanks    EDIT1:  Don't understand why I got downvotes.  Did I make it clear that I managed to install the driver?  Yes I've read  before,  but it didn't work.  The problem I've got is not trouble in installing the driver,but in that I have difficulty in consistent internet access.  I don't know how to solve this problem,so I taged with drivers,because I thought that could be one of the main causes.  btw,this PC works fine with Windows 8.Hate to say this,but the wireless card works fine with Windows 8.  Thanks anyway.  EDIT2:  Sorry that I don't understand what I should explain again....  But I really don't know why I just don't have a consistent wireless connection.  As I've mentioned,I've followed the steps from every list I've found to reinstall the driver I've got again and again.I managed to get access to network but I get disconnected really quickly.  Again,I'm quite sure it's not the problem of the network,as I've tried again on Windows 8,it's working fine.  Any idea is welcomed,  I'm really confused at the moment.Thanks anyway  EDIT3:  Can you please tell me the reason of your downvotes?  Is there an obvious way to solve the problem?  Please help me out of this!Thanks


Sums in equation: how to display index under the sigma sign?

Consider this example: \documentclass{article} \begin{document} \begin{equation}   \sum_i a \end{equation}  \begin{equation}   \frac{c}{ \sum_{i}b } \end{equation} \end{document}  How in equation 2 can I display the index under the sum sign as in equation 1?


Is complete linkage found in all four chromosomes or only Y-chromosome of Drosophila?

Male Drosophila shows complete linkage. Is it observed for all four chromosomes or only the Y chromosome?


Create an sql query for two tables for a one-to-many with pivot relation conversion

I need assistance creating a query for two tables.    The first table books already has an author (the author's name) and illustrator (illustrator) in the author and illustrator column.  The second table people also has the name of the author in the name column. The third table books_people has the two columns book_id and author_id and a third column called occupation   This is more of a conversion from having the authors directly in the books table to having a separate table creating a relation between two tables (one-to-many) ( table: books_authors ). I would also need help making the column of that relation submit the occupation.  Books Table:   +----+--------------+----------------+-----------------+ | id |    title     |     author     |     artist      | +----+--------------+----------------+-----------------+ |  1 | Tower of God | SIU            | SIU             | |  2 | Zippy Ziggy  | KIM Eun-jung   | HWANG Seung-man | |  4 | Beelzebub    | Tamura Ryuuhei | Tamura Ryuuhei  | +----+--------------+----------------+-----------------+   People Table:   +-------+-----------------+ |  id   |      name       | +-------+-----------------+ |    32 | SIU             | |  4053 | KIM Eun-jung    | |  4055 | HWANG Seung-man | | 28490 | Tamura Ryuuhei  | +-------+-----------------+   Books_People Table   +----------+-----------+----------------+ | comic_id | person_id |   occupation   | +----------+-----------+----------------+   Expected result:   +----------+-----------+----------------+ | comic_id | person_id |   occupation   | +----------+-----------+----------------+ |        1 |        32 | author, artist | |        2 |      4053 | author         | |        2 |      4055 | artist         | |        4 |     28490 | author, artist | +----------+-----------+----------------+   What im trying to do here is "create" the rows after the relations have been made.


Render issue - Model doesn't appear to be on any layers and won't render

Really odd on this... using Blender 2.75... I started modelling and lost the objects from the 3d view, but they were still showing in the object lists on the outlier... I was able to copy them and continued working... when I did a test render I discovered that only the original lost objects were rendering and nothing that I had modelled over the previous 2/3hrs was showing up...  I have no idea what I did but I created another 3d view and the original bits showed up along with the layer buttons which had been missing from the screen which I thought was just a new feature from  2.75...!  Picture to show the 2 screens, top one doesn't render but bottom one does    Any idea's what I've done?


my question is: How can I launch an action after a time of inactivity user in Javascript?, for example, in my app the user can navigate across the content and leave it in a section, lapsed a specific time, return to the homepage. Any idea?


I am trying to cron an rsync sync over ssh, but for some reason, as soon as I put the command in cron, it won't run. I don't know what is causing it to break, but it is certainly something related to the fact that it is placed in cron because:   If i copy paste the command in my shell prompt, it will execute as expected. if I replace the command in cron by a simple command such as date > /root/synclog.log, cron does fire it up as expected.   Here's the code:  * * * * * flock -n /root/synclockfile -c "rsync -avv --stats -h --log-file=/root/synclog.log --log-format='%t %f %b' --ignore-existing -e ssh /shares/myshare/PHOTOS/ my_server_hostname:/backups/PTHOTOS"   What could be wrong?


I am keep getting output as below:  Inside AuthenticationFilter.. Inside Session!   why session not getting cleared after browser closed? I even kepted page session=false inside index.jsp too , but still not working.. Please someone look into below code and help me getting session cleared after browser window closed.  Below is the code:  index.jsp  <%@ page session="false" %> <%  /* ServletContext context= getServletContext(); RequestDispatcher rd= context.getRequestDispatcher("/login"); rd.forward(request, response); */  response.sendRedirect("login");  %>   loginServlet  import java.io.IOException; import java.io.PrintWriter;  import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession;  /**  * Login servlet.  */  @WebServlet("/login") public final class LoginServlet extends HttpServlet {      private HttpSession session = null;     private RequestDispatcher rd = null;      /**      * Respond to a GET request for the content produced by      * this servlet.      *      * @param request The servlet request we are processing      * @param response The servlet response we are producing      *      * @exception IOException if an input/output error occurs      * @exception ServletException if a servlet error occurs      */     @Override     public void doGet(HttpServletRequest request,                       HttpServletResponse response)       throws IOException, ServletException {          System.out.println("Inside Login Servlet...");          PrintWriter out = response.getWriter();         out.print("<h3> This is login servlet poage ... </h3>");      } }    AuthenticationServlet  import java.io.IOException;  import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession;   @WebFilter("/*") public class AuthenticationFilter implements Filter{      private HttpSession session = null;      public void init(FilterConfig arg0) throws ServletException {}        public void doFilter(ServletRequest req, ServletResponse resp,           FilterChain chain) throws IOException, ServletException {          System.out.println("Inside AuthenticationFilter..");          HttpServletRequest request = (HttpServletRequest) req;         HttpServletResponse response = (HttpServletResponse)resp;          session = request.getSession(false);         if(session != null && !session.isNew()) {             System.out.println("Inside Session!");         } else {             getAccessToken(request, response, chain);             chain.doFilter(request, response);         }      }        public void destroy() {}        private void getAccessToken(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException {          session = request.getSession();         System.out.println("Created new  Session!");     }  }


Currently creating a datapack for a custom recipe but i dont know how to name my result after the items have been put in

So I'm using a JSON editor to create my crafting recipe and at the moment I can't seem to figure out how to name my result item. Any help?  Code:    {      "type": "minecraft:crafting_shaped",     "pattern": [         "#W#",         "DED",         "L L"     ],     "key": {         "#": {             "item": "minecraft:lapis_block"         },         "W": {             "item": "minecraft:water_bucket"         },         "D": {             "item": "minecraft:diamond_block"         },         "E": {             "item": "minecraft:diamond_leggings"         },         "L": {             "item": "minecraft:lily_pad"         }     },     "result": {         "item": "minecraft:diamond_leggings",         "count": 1     },     "group": "Armour" }


What is the relationship between redshift and conformal time ?   For example in a paper i found:   taking $z_e = 3234 $ at the time of radiaton-matter equality yields the conformal time $\frac{\eta_e}{\eta_0} = 0.007$ and taking $z_E=0.39$ at matter-$\Lambda$ equality yields $\frac{\eta_E}{\eta_0}=0.894$ and setting redshift at decoupling $z_d=1089$ yields $\frac{\eta_d}{\eta_0} = 0.0195$  where $\eta_0$ is the present decoupling time.  Further some cosmological parameters are given as :  $\Omega_r = 8.36 \times 10^{-5}, \Omega_m = \Omega_b + \Omega_{dm} = 0.044 +0.226, \Omega_\Lambda = 0.73,  H_0=0.72$  Now how can i calculate all those $\eta_e, \eta_E, \eta_d, \eta_0$ from given redshift values and/or above parameters ? I searched whole of my text books trying to find an explicit relation for conformal time $\eta$ but all i got was $ \mathrm{d}t=a(t)\mathrm{d}\eta$. Any help would be very helpful.


Why negative times negative is positive?

I know that many people would say I don't even know this. But I know it very well that negative × neagtive = positive. But I don't know Why? So kindly give a logical answers.


Why does Picasa change the RAW preview after a second?

I love viewing RAW images through Picasa, as it's a free viewer and works for all RAW files. But there's sometihng I don't like — the auto adjust/enhance feature. After opening a RAW file, the preview gets changed after a second.   How to configure Picasa so it shows only the unedited RAW file?


Google search results showing up a URL on its search which doesn't exist on the website

I am using a keyword to display a website page on google search. After entering the keyword, on the first page of google, I am redirected to a page, whose domain is exactly similar to the website whose page I want to display, but it is showing a page which doesn't even exist on the domain. Also, as similar domain with spam characteristics is also getting displayed.   To practically demonstrate this issue, do follow the below steps.   Go to  Type dolce streichquartett and click on search. The 4th/5th URL has this link http://www.dolce-streichquartett.de/?high_ry=/casinos/de/spielautomaten-casino-bregenz.php, which is no where on the website and looks like spam The 7th/8th link you see is http://deonlinecasino.org/doc/kostenlos-roulette-spielen-spielgeld-ausdrucken.php, which is exactly similar to the above with the title as the keyword but a different domain.   What is this issue and why is this happening?


So I've tried a bunch of sets and I believe the statement to be true. However I am not quite sure how to formulate a correct proof. I know so far that for an element x in set $C$, it cannot be in set $A$ or $B$. And on the right side, we are taking the union of the sets where for an element $x$, $C\setminus A$ and $C\setminus B$ is $x$ that is in $C$ but not $A$ and $B$.


Derivative of sigmoid function $\sigma (x) = \frac{1}{1+e^{-x}}$

In my AI textbook there is this paragraph, without any explanation.     The sigmoid function is defined as follows      $$\sigma (x) = \frac{1}{1+e^{-x}}.$$      This function is easy to differentiate because      $$\frac{d\sigma (x)}{d(x)} = \sigma (x)\cdot (1-\sigma(x)).$$   It has been a long time since I've taken differential equations, so could anyone tell me how they got from the first equation to the second?