yesterday I bought a laptop which contains both a Nvidia 940mx graphics card and Intel Integrated Graphics. I have found that it uses the Intel integrated graphics by default, but I wish for it to use the Nvidia card instead.  I have already tried switching while using Arch Linux and have switched to Ubuntu in hopes that it will work here, as when I made an attempt on Arch Linux, it resulted in the X Server being entirely unable to start, reporting that it is unable to locate the display, or something along those lines. Because I have already had this issue with switching, I am hesitant to try again without first ensuring that everything will work correctly.  There seem to be several conflicting (and outdated) guides for switching to the nvidia card. Using vga_switcheroo did not work, as the /sys/kernel/debug/vgaswitcheroo/switch did not even exist. Any existing questions on stack exchange which describe utilizing the nvidia card are either outdated, inconsistent with all the others, or are not consistent with my situation.  Some Hardware Information:  $ lspci -nnk | grep -i vga -A3 | grep 'in use' Kernel driver in use: i915  $ lshw -short | grep display /0/100/2                     display        Intel Corporation /0/100/1c/0                  display        NVIDIA Corporation  $ lshw | grep -A10 "VGA\|3D"          description: VGA compatible controller          product: Intel Corporation          vendor: Intel Corporation          physical id: 2          bus info: pci@0000:00:02.0          version: 02          width: 64 bits          clock: 33MHz          capabilities: vga_controller bus_master cap_list rom          configuration: driver=i915 latency=0          resources: irq:131 memory:b2000000-b2ffffff memory:c0000000-cfffffff ioport:5000(size=64) memory:c0000-dffff --             description: 3D controller             product: NVIDIA Corporation             vendor: NVIDIA Corporation             physical id: 0             bus info: pci@0000:01:00.0             version: a2             width: 64 bits             clock: 33MHz             capabilities: cap_list             configuration: latency=0             resources: memory:b3000000-b3ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:4000(size=128) memory:b4000000-b407ffff  $ lspci -nnk | grep -i "VGA\|3D" -A3 00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:5916] (rev 02)     Subsystem: Acer Incorporated [ALI] Device [1025:111a]     Kernel driver in use: i915     Kernel modules: i915 -- 01:00.0 3D controller [0302]: NVIDIA Corporation Device [10de:179c] (rev a2)     Subsystem: Acer Incorporated [ALI] Device [1025:111a]     Kernel modules: nvidiafb, nouveau 03:00.0 Network controller [0280]: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter [168c:0042] (rev 31)  $ sudo ubuntu-drivers devices                              == cpu-microcode.py == driver   : intel-microcode - distro non-free  == /sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0 == vendor   : NVIDIA Corporation modalias : pci:v000010DEd0000179Csv00001025sd0000111Abc03sc02i00 driver   : xserver-xorg-video-nouveau - distro free builtin driver   : nvidia-367 - distro non-free recommended  $ arch x86_64   Given this information, what is the safest way for me to switch from the intel device to the nvidia graphics card without a risk of breaking the X server? This system is running Ubuntu 16.10 Yakkety.

So I updated to Ubuntu 14.04 and found that the primusrun command no longer works, so ditched bumblebee in favour of nvidia-prime. This lets you switch video card from nvidia-settings rather than running through the command line (I prefer the old method, but want the primus performance).  The problem is that after switching to Intel from nvidia-settings, I can no longer open it up again to switch back to the nvidia card. When I open nvidia-settings I get a segmentation fault (according to the terminal).  Is there any way to open nvidia-settings switch back? I would like the ability to be able to switch between the two since having the nvidia card on all the time kills my battery and heats up the laptop a lot.


I have data on exchange rates, where I have calculated the mean and the standard deviation of the payoff. I am able to run a regression (payoff regressed on a constant) and get the standard error of the sample mean.   Is it possible to either do the same with the standard deviation or calculate from a formular and get the standard error of the standard deviation?

I read from  that the standard error of the sample variance is  $$SE_{s^2} = \sqrt{\frac{2 \sigma^4}{N-1}}$$  What is the standard error of the sample standard deviation?  I'd be tempted to guess and say that $SE_{s} = \sqrt{SE_{s^2}}$ but I am not sure.


Hi i wanted to know is it possible to call a codebehind function in my Javascript? The javascript is in the head of my asp.net webpage page.   I have tried many methods but none seem to have worked. Its the first time iv had to do this so an example would be a nice learning curve fix.  My codebehind function in C#  protected void GetAverageRent_TextChanged(object sender, EventArgs e) {     string Postcode = _postCodeInput.Value.ToString();     var webGet = new HtmlWeb();     var doc = webGet.Load("http://www.webadress.com/" + Postcode);       HtmlNode AvgPrice = doc.DocumentNode.SelectSingleNode("//div[@class='split2r right']//strong[@class='price big']");      if (AvgPrice != null)     {         AverageRentLbl.Text = AvgPrice.InnerHtml.ToString();     }     else     {         AverageRentLbl.Text = "Invalid Postcode!";         AverageRentLbl.ForeColor = Color.Red;         AverageRentLbl.Font.Bold = true;     } }   My Javascript  <script> function codeAddress() {          document.getElementById('map-canvas').setAttribute("style", "height:200px");          geocoder = new google.maps.Geocoder();         var latlng = new google.maps.LatLng(-34.397, 150.644);         var mapOptions = {             zoom: 16,             center: latlng,             mapTypeId: google.maps.MapTypeId.ROADMAP         }         map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);          //var address = document.getElementById('_mainContentHolder__postCodeValue').value;         var address = document.getElementById('ContentPlaceHolder1__postCodeInput').value;          geocoder.geocode({ 'address': address }, function (results, status) {             if (status == google.maps.GeocoderStatus.OK) {                 map.setCenter(results[0].geometry.location);                 var marker = new google.maps.Marker({                     map: map,                     position: results[0].geometry.location                 });                  document.getElementById('ContentPlaceHolder1__latValue').value = results[0].geometry.location.lat();                 document.getElementById('ContentPlaceHolder1__longValue').value = results[0].geometry.location.lng();             } else {                 alert('Sorry the postcode you entered in invalid. Please try again: ' + status);                 document.getElementById('ContentPlaceHolder1__postCodeInput').value = "";             }         });</Script>

I'm writing a web page in ASP.NET. I have some JavaScript code, and I have a submit button with a click event.  Is it possible to call a method I created in ASP with JavaScript's click event?


Given a complex vector space $\mathcal{V}$, its complex conjugate $\overline{\mathcal{V}} = \{ \overline{v} : v \in \mathcal{V} \}$ consists of the "same" set of points (according to a number of references...). I'm struggling to reconcile that with the following example:    Define $ \mathcal{V} = \mathrm{span}_{\mathbb{C}}\{(1,i)\} = \{ (\alpha + \beta i, -\beta + \alpha i) : \alpha,\beta \in \mathbb{R} \}\,. $ Then, $(1,i) \in \mathcal{V}$ and so $\overline{(1,i)} \in \overline{\mathcal{V}}$, but $\overline{(1,i)} = (1,-i) \notin \mathcal{V}$. Thus, some vectors in $\overline{\mathcal{V}}$ are not in $\mathcal{V}$ (and vice versa).     Edited to add proposed solution (based on comments):   Complex conjugation on $\mathcal{V}$ can be (re)defined as   $$     \overline{(\alpha + \beta i, \, -\beta + \alpha i)}        = (\alpha - \beta i, \,\beta + \alpha i) \in \mathcal{V} \,.   $$     Am I missing something? If $\mathcal{V}$ is a complex vector space, then how do we reconcile it as having different vectors than its complex conjugate? On the other hand, if $\mathcal{V}$ isn't a complex vector space, then what is it?

I am starting reading about Hodge theory and while reading the definition of abstract Hodge structure a very basic question came to my mind... What is the definition of the conjugate of a subspace of a complex vector space?  I found online the definition of conjugate of an entire vector space, but when we do the Hodge decompostition we want $V_{\mathbb{C}}=\oplus_{p,q \in \mathbb{Z}}V^{p,q}$ with the requirement $\overline{V^{q,p}}=V^{p,q}$. So I want to take a conjugate inside the space $V_{\mathbb{C}}$. I can see it if my space is of differential forms, but what is the definition for an abstract one?  Also, if I take the tensor product of two vector spaces, is this conjugation induced componentwise?  I know the question is pretty basic, but I couldn't find any reference for such definitions.


For my raytracing needs, I'd like to find a way to compute a normal from a given 3d equation. This equation can be either a parametric one or a cartesian one (preferably in canonical form).  From my researches on the internet, it seems to be doable by computing the gradient of the equation but I want to be sure about that.  I manually tried to test against the sphere cartesian equation and it worked but that's not enough to prove that that is the solution.

From this , I now understand the gradient to be the directional derivative that returns the steepest slope at a point. However, reading my textbooks, they all say that the gradient is normal to the tangent plane. In the above SE question, the gradient sounds like it should be parallel to a direction in the $xy$ plane, not actually up on the surface.   My question is therefore do I have a misunderstanding of the tangent plane, gradient or directional derivative?   In addition, I question how the gradient always passes through the origin or the $xy$ plane? If for instance in the graphic, the gradient had been another direction (say horizontal), then it wouldn't pass through the origin! In addition, the gradient of other points in the graphic would satisfy this example. Many thanks!


I have a scenario where i have to I need to find the files for a specific year for eg- 2012 and empty the files. Trying to use the below command which is throwing   #!/bin/bash find . -type f -newermt 2012-01-01 ! -newermt 2012-01-01 -exec truncate -s 0 {} \;  find: invalid predicate `-newermt' error Below is the command   Strange thing is this command works for some people.Found that there may be some version compatibility issue for the find with the predicate 'newermt' for my system.  So just wanted to check   1. So how can i resolve the above error 2. Is there any way by which i can perform my task i.e, - find the files for a specific year for eg- 2012 and empty the files.

How do I use the UNIX command find to search for files created on a specific date?


Today I got the following message:    Computer was frozen and the only button available was "Get Updates".  I don't need this feature, I need to work, not serve my machine the time she wants.  Currently I did cold reboot and had time to open task manager and process explorer on different screens before the message appears again. Due to the bug in the application, I was able to kill MusNotification.exe process.  Unfortunately, I am unable to restrict system access to musnotification.exe and musnotificationux.exe files, or add them to antivirus blacklist.  How to ban this feature?

We've upgraded some machines to Windows 10 and realized there were some updates which updated as required. However, I realized there was no option available to stop the download similar to that on Windows 7 and 8.1. The only way I could stop the download was to stop the Windows Update service.  My question is does anyone know of a way to stop auto updates or is stopping the service is the only solution?


I'm trying to use the Flow Trigger for both before/after update. Question is there any way to get compare the old vs new values in the record? I review few articles but none of the suggestion works -Cannot use function: IsChanged -Tried getPriorValue.fieldName__c, but it show syntax error -Query the record might worked for before but not for update (haven't try it) It seems to me unreasonable that trigger tool won't have such option....

I'm using a flow to set a field to a certain value (01, 02, 03) depending on the value of another field on the same record. I initially wanted to do it with process builder but because of the mapping it seems I would need three 'criteria nodes' or a formula field. Furthermore, it seems Salesforce is recommending using flows instead of process builder for before update actions as it is faster.  The problem with Flows is that I found a way to trigger it when the record is new or updated but not when the specific field is changed so it triggers every time the whole record is updated even when the field stay the same.  On Process Builder, you can use isChanged and then call the flow with specific record but that kinds of defeat the point of using flows for before Update.  So is there a possibility to do the same thing directly in flow ?  Thank you for the help !


I know arrays are faster at getting and setting, while LinkedLists are better at adding and removing elements, but what about when iterating? A more "traditional" for(i=0;i<intList.size();i++) would definitely make LinkedLists slower since you'd have to get the element at index i every time. But what if I use for(int i : intList)? How does it work under the hood for this instance? For example:  LinkedList<Integer> intList = new LinkedList(); /* populate list... */ for (int i : intList) {     //do stuff }   I imagine that there's no need to get an specific element when going through the whole List, so it should be possible to have some sort of loop implementation where performance is about the same. Though I don't know how exactly how for is implemented for this example so I can't be sure if this is it.

I've always been one to simply use:  List<String> names = new ArrayList<>();   I use the interface as the type name for portability, so that when I ask questions such as these I can rework my code.    When should  be used over  and vice-versa?


If you do not want to differentiate gender of a person being referred to, for instance in public or legal notices, why is there no single word for the following word pairs?   (he,she), (him,her), {his,her)    It appears to be a big limitation in many languages...

I see sentences with (he or she) like :     How to know if he or she is the best one for you?      Give a Person Power and He or She Will Show Interpersonal Sensitivity.   It's possible to use just one word instead of (he or she), something like :     Give a Person Power and He Will Show Interpersonal Sensitivity


I am planning to start a homebrew fantasy savage worlds campaign with my friends over roll20.  We have already played together in a d&d 5e campaign over the past year and now starting a new one.  The problem is that all of us have pretty busy schedules, which means that each session, at least one of the players will be missing. The problem existed in the previous campaign too, the differnce is that I used a pretty railroady campaign and now I want a more homebrew open world kind of adventure.  How can i run a meaningful adventure keeping that in mind?

If you know ahead of time that you're going to be missing a player, do you reschedule? Or just play them as an NPC or as a group puppet?


I installed Darktable in the past through Ubuntu Software Center and it worked perfectly. However, in the Darktable preferences tab, OpenCL was not enabled.   I really want to have OpenCl enabled as it boosts Darktable's performance. Thus I made sure I had the correct NVIDIA driver that allows OpenCL configuration enabled and tried running darkatbe-cltest, which failed and showed this error message:  darktable-cltest not known  You can install it with sudo apt install darktable   I was a bit confused, because I already had Darktable installed as described above.   But I did proceed with sudo apt install darktable, which installed a new version of Darktable on my computer.   I also used sudo add-apt-repository ppa:pmjdebruijn/darktable-release, in order to update to the newer version. Oddly, this new version now supports OpenCL!  Now I have 2 different versions of Darktable on my computer, both version 2.6.2. However, one supports OpenCL, while the other does not. Also the layout of the two versions is slightly different (different font size and padding).  When I run Synaptic, I can only see one version of Darktable, the one installed from the terminal.   And when I try to find packages installed through Ubuntu Software Center, like Discord, I can't find them in Synaptic.   Because I thought Ubuntu Software Center was a GUI of the terminal, it is a bit strange not to find every package installed in Ubuntu Software Center.  (NB: I have to mention that I did run sudo apt-get update  && sudo apt upgrade a few times and also  updated through Synaptic some of the packages I saw there.)

So, thanks to this bug:  I would rather not use Snap packages. The only one that I really use is Calculator but I would like to replace all of them with a deb version. How would I go about it?


I use QGIS 2.18.5 and I get in stuck with two polygons I cannot solve. The two polygons I have looks like:  What I want to get is circled with red:  What I tried/made: Cut 1 polygon and paste to other layer. Used polygon to lines toolbox then explode lines, then deleted the lines which do not needed then used the add feature to connect lines. Last I dissolve new lines then convert lines to polygons. The new polygon looks like that I wanted to get in QGIS but when I use wayline converter which convert polygons to my tractor GPS it is only shows that polygon what was originally on that layer when I started. Look I deleted the line I do not need:  When I select Vertex Tool it appears the line I deleted earlier:  I think this is the main problem but I do not know how to remote it well.. How can I solve this problem?

I use QGIS 2.18.5 and I get in stuck with two polygons I cannot solve.  I want to make a new polygon from these two which looks like this:  I made thew new one: Cut 1 polygon and paste to other layer. Used polygon to lines toolbox then explode lines, then deleted the lines which do not needed then used the add feature to connect lines. Last I dissolve new lines then convert lines to polygons. The new polygon looks like that I wanted to get in QGIS but when I use wayline converter which convert polygons to my tractor GPS it is only shows one polygon:  What could be the problem?  Look I deleted the line I do not need.  When I select Vertex Tool it appears the line I deleted earlier.  I think this is the main problem but I do not know how to remote it well..   I found it but is is not the result I wanted to get. :D Look I want to this from 2 Polygons: I want that new polygons that is circled with red:  After used the Minimum Bounding as Minimum Oriented Rectangle I got this:


I'm brewing my first batch ever, we did our best but something is going on in the fermentation and I'm not sure what it is.  Here is a 30 sec video of the issue:   Basically there is a lot of foam and the airlock is overflowed by it. Data: - The initial density of this batch was 1050, even though we tried to make it less, our initial malt/water ratio during the maceration phase was a bit off so the density was huge. - The yeast we used was a 11gr Golden Ale (0.3 oz) - The amount of wort is around 20lts (5.2 gallons)  We were worried a bit about the high density and the yeast being very little, but a brewer friend of mine told me it would just delay the fermentation because the yeast will have to multiply more before it starts fermenting. And it did, fermentation took close to 48hs to start.  Thanks for any input you might give :) hopefully we will save the batch.

During my last small batch brew, , I came home to find that the foam in the 1 gallon carboy had overflowed the three-piece air lock (which was a mess to clean out). I have read that if it looks like it may bubble over, one can use a hose to create an airlock using a bowl of water. However, it overflowed while I was away, and I did not see it coming. I changed out the airlock for another one that I had, and let it proceed.  1) Is there a way to avoid this? Was there possibly too much wort in the carboy?  2) What are the possible effects on fermentation process, if any?


I have a class called LB_Adapter.java made to help show my database in a ListView. All functionalities of my program work fine, but I still get an warning error every time I compile that says  Note: Project/LB_Adapter.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.   From googling I understand the error comes from my ArrayList, but I've tried implementing ArrayList() which doesn't work. Is there a way to get rid of the error, or does it even matter since it doesn't affect anything?  Relevant code:  public class LB_Adapter extends ArrayAdapter<Object> { List<Object> list = new ArrayList<>();  public LB_Adapter(Context context, int resource){     super(context, resource); }  public void add(LB object){     list.add(object);     super.add(object); }  @Override public int getCount(){     return list.size(); }  @Override public Object getItem(int position){     return list.get(position); }  @Override public View getView(int position, View convertView, ViewGroup parent) {     View row = convertView;     LBHolder lbholder;      if(row==null){         LayoutInflater layoutinflater = (LayoutInflater) this.getContext().getSystemService(getContext().LAYOUT_INFLATER_SERVICE);         row = layoutinflater.inflate(R.layout.display_leaderboard_row, parent, false);         lbholder = new LBHolder();         lbholder.lb_rank = (TextView) row.findViewById(R.id.lb_rank);         lbholder.lb_score = (TextView) row.findViewById(R.id.lb_score);         lbholder.lb_time = (TextView) row.findViewById(R.id.lb_time);         row.setTag(lbholder);     }     else {         lbholder = (LBHolder) row.getTag();     }     LB leaderboard = (LB) getItem(position);     lbholder.lb_rank.setText(leaderboard.getRank().toString());     lbholder.lb_score.setText(Integer.toString(leaderboard.getScore()));     lbholder.lb_time.setText(leaderboard.getTime().toString());      return row; }  static class LBHolder{     TextView lb_rank, lb_score, lb_time; } }

For example:  javac Foo.java Note: Foo.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.


I am used to the definition of continuity used in real analysis, based on the idea that if $f$ is continuous at $a$, you can get arbitrarily close to $f(a)$ by going arbitrarily close to $a$.  However, the topological concept of continuity of $f: M \to N$ is the condition that for all $S \subset N$, the preimage of $S$ in $M$ must be open subsets.   What does this have to do with the intuitive concept of "continuity"? I cannot even picture how this relates to continuity in Euclidian space, let alone how it would relate to continuity in more abstract topological spaces.

Let $X$ and $Y$ be topological spaces. A function $f: X \rightarrow Y$ is defined as continuous if for each open set $U \subset Y$, $f^{-1}(U)$ is open in $X$. This definition makes sense to me when $X$ and $Y$ are metric spaces- it is equivalent to the usual $\epsilon-\delta$ definition. But why is this a good definition when $X$ and $Y$ are not metric spaces?  How should we think about this definition intuitively?


Snell's law tells us that, Sine of angle of incident of light by sine of angle of refraction of light, when light travels from one medium to other, is a constant(for that mediums). It is also related as ratio of speed of light in two mediums. This ratio is also a constant. But, how they both are equal? How we came up with this?

I recognize that Snell's Law relates indices of refraction and the angles of incidence and refraction, but why does the equation use sine to describe those angles and not simply angle values? It would seem that angle values would make the most sense since it directly refers to the size of the angle entering or exiting mediums. What is it about the sine function that makes it essential to the correctness of Snell's Law?


As an example, I have the following list:  ['ABC','DEF','GHI','JKL']   By my reckoning, there should be 26 combinations i.e.  ABCDEFGHIJKL ABCDEFJKLGHI ABCGHIDEFJKL ABCGHIJKLDEF ABCJKLDEFGHI ABCJKLGHIDEF ...   How would I do this in Python?  Thanks

How do you generate all the permutations of a list in Python, independently of the type of elements in that list?  For example:  permutations([]) []  permutations([1]) [1]  permutations([1, 2]) [1, 2] [2, 1]  permutations([1, 2, 3]) [1, 2, 3] [1, 3, 2] [2, 1, 3] [2, 3, 1] [3, 1, 2] [3, 2, 1]


I looked up a method of opening multiple files in separate instances of MS Excel, as I have both a landscape oriented and portrait oriented monitor and need to use both. The common method of doing so was to enable a function called "Ignore other applications that implement DDE (dynamic data exchange)" or similar.   Now that I have applied this option, whenever I open files in Excel, I receive the error;      There was a problem sending the command to the program.   Microsoft and other sources list the resolution as "Disable the DDE ignore function". This will place me right back where I started.  Is there a method of opening each file in a separate instance of the Office program, without making Office prone to this error?

I want to be able to compare to large spreadsheets side by side...  Since you can not natively expand to all monitors I would like to have the two documents open in two instances.  These files are links on Sharepoint.


What is the difference between revoked and annulled Schengen visa? Does it means the same thing, or are they separate?

I applied for a Schengen visa 2 years ago and got it, but the visa was revoked because I tried to travel to another Schengen country, which I wasn't allowed to due to the limitations on my Schengen visa.  I was giving some days to vacate the country, which I did. I wasn't deported – it's a voluntary departure – but the earlier visa given was canceled.   Since my earlier circumstance has changed, can I re-apply for a new Schengen visa and this time?  Or am I going to be refused because of my earlier visa revocation, which I still have on my passport?  I am only visiting the country that is going to issue the Schengen visa. The earlier visa was issued by the Latvian embassy; now I intend to travel to Estonia as a tourist again.


If Voldemort had survived his final duel with Harry Potter and decided to reform and live on in peace, would it be possible for him to live for eternity? Or rather, in universe, if Voldemort decided to quit after book 6, would he have been able to live for eternity? Would his body survive the vagaries of time, or would he be susceptible to a normal death due to some ailments perhaps or just old age?

A more general question is: Can a witch or wizard die a natural death as long as her/his horcruxes exist?  Looking for canonical answer only. Rowling's interviews etc are welcome, too.


I installed OpenStack and then I shutdown the laptop. After turning on the laptop again I can't enter the programmer.  How can I save my work in Ubuntu?

Is there a way to save all my typed terminal commands and view it like history in a log book?


Many people have come to Meta to vote and comment on the . However most people coming from other sites don't have enough reputation to down vote answers. This completely skews the votes and could give an incorrect perception of the community's views. According to the :  Voting is different on meta. Like normal Stack Exchange sites, Meta allows members to vote on questions and answers. For most posts, votes reflect the perceived usefulness: well-written, well-reasoned, well-researched posts tend to get more attention and more upvotes. Highly-voted and frequently-linked posts may become part of the community-curated FAQ or codified as part of the site’s Help pages. Unlike normal Stack Exchange sites, Meta invites the community to discuss, debate and propose changes to the way the community itself behaves, as well as how the software itself works. On posts tagged feature-request, voting indicates agreement or disagreement with the proposed change rather than just the quality or usefulness of the post itself.  However unlike every other Meta site on the network, on meta.SE users gain and lose reputation through votes. So down voting costs you reputation and votes on your questions and answers affect your reputation. Hence people will be less likely to down vote answers and people will be less likely to post questions and answers if they will get down votes which might affect their privileges. Especially since the majority of users will have very low reputation here. An example is this very question. My privileges on meta.SE should not be changed by votes which show people's agreement or disagreement with the question. And we should be able to post suggestions and vote on questions and answers to show our agreement and disagreement without having affecting our privileges. If voting on meta is supposed to be different then the reputation and voting system should also be different to other SE sites. I would suggest making the reputation on meta.SE the same as your highest reputation from the other SE sites you're a member of. Then have no reputation changes on meta.SE. I do not think that simply lowering the bar for down voting is correct. Reputation change and privilege change will affect voting and participation behaviour, skewing voting towards up votes only and acting as a barrier to participation. Related

To make your opinion known on MSE you need both up and downvotes. Given at the moment you need 125 rep to downvote on this site, the voting patterns will be skewed positive because not everyone is active on the site.   This is to be expected for regular Stack Exchange sites as you are expected to be involved in the community before you are deemed knowledgeable enough to be part of the community voice. However, MSE is different because you are voting for the entirety of the Stack Exchange network and you shouldn't need to be active on MSE itself to have a voice on changes to the entire network.  This is especially important for questions like  because it will effect every network to do with coding at all. This was brought up in .  I would suggest reducing the rep required to downvote on MSE down to 100 (or 101) rep. This is the amount you get for the site association bonus. This is given once you achieve 200 rep on any network site and shows that you are active in at least one community. I think this would be the perfect use of the association bonus in showing that you are a member of the Stack Exchange community.


We have a CentOS server for our web startup hosted on softlayer.com. Knowing how secure Linux is even without anti-virus programs: Do I still need to install McAfee as advertised in softlayer's site ()? Is it worth installing? What benefits will it provide me?   Thanks!

Over last year we have tried to deploy antivirus software on production linux servers.  In most cases after a few weeks under month end loads applications start running slow, or do not work as it should.  I have always questioned to reason for having antivirus on linux, but it just seems a be must have item on auditors list.  It is my understanding that the amount of linux malware is little in comparison to windows, which brings me to my question why linux servers are required to have anti virus in terms of SOX?    We have tried 2 different anti virus products and both deployments where rolled back on critical servers.  Should we just put a compensating factor in place and forget about anti virus on linux altogether


There are several moderators that abuse their powers, and I want to seek justice and report them to the actual owners on this site. How can I accomplish this request?

Possible Duplicate:          Is there anywhere or anyone to complain to about the behaviour of moderators? I've been "spoken" to offensively by a moderator, and I'm unhappy about it.


What's the meaning of "##" in the following?  #define CC_SYNTHESIZE(varType, varName, funName)\ protected: varType varName;\ public: inline varType get##funName(void) const { return varName; }\ public: inline void set##funName(varType var){ varName = var; }

As mentioned in many of my previous questions, I'm working through K&R, and am currently into the preprocessor. One of the more interesting things — something I never knew before from any of my prior attempts to learn C — is the ## preprocessor operator. According to K&R:     The preprocessor operator ##   provides a way to concatenate actual   arguments during macro expansion. If a   parameter in the replacement text is   adjacent to a ##, the parameter is   replaced by the actual argument, the   ## and surrounding white space are   removed, and the result is re-scanned.   For example, the macro paste   concatenates its two arguments:      #define  paste(front, back)  front ## back      so paste(name, 1) creates the token   name1.   How and why would someone use this in the real world? What are practical examples of its use, and are there gotchas to consider?


I have installed my webserver from a computer at home. On Ubuntu Server, LAMP, everything works fine except email sending.  First I was getting:     Unable to send email   then I followed .  Then I still got same error. I checked Apache logs and I found   sendmail: fatal: file /etc/postfix/main.cf: parameter myhostname: bad parameter value: myservername.{null}   I changed the file and wrote my website domain like domain.com  At last, Drupal says "Email sent" but I receive no email. What is the problem?

When my web form is filled and submitted, I get redirected to a page that says:     Thank you for submitting.   but theres a red warning box there that says:     Unable to send e-mail. Contact the site administrator if the problem persists.   I think its the SMTP server, but I don't know how to fix that.


My grandparents never altered their  since buying it on Aug 1 2018. It could effortlessly slash coconut and raw , but now it can't even cut paper or pears or ! Undeniably they must alter their knife.   Before they buy a honing rod and/or , how can they infer if it must be honed and/or sharpened?

As per the question - how to I test that a knife is sharp enough? And/or, how do you know when a knife needs sharpening?  Edit: Yesterday I attempted (I feel quite successfully) to hone my knives for the first time ever (requiring me to purchase a honing steel), which immediately made a rather noticable difference (I shall be honing them regularly from now on). Not sure whether additionally sharpening them as well would be a good idea? The suggested tomato and paper tests make sense, and I shall try them in the near future and see..


Do:     'I have had that experience'    and:      'I have experienced that'    mean the same thing? Can they be used interchangeably?  Or are they two different things?  For example:      Person 1: Have you ever dated a female cop?   Person 2: Nope   Person 1: I have had that experience / I've experienced that      I've had that experience implies that person 1 was dating a cop at sometime in the past. When is not important. The present relevance of his past experience is what matters (he knows what it's like to date a cop and the sequel of events that one has to go through when dating a cop).   I've experienced that is not even a likely response in this context as far as I think  Experience as a noun means "practical contact with a sequel of events." But as a verb, it means "to go through a situation." So I've had that experience implies that the experience wasn’t, perhaps, a pleasant one. But with I've experienced that there's no such implication.   In this case, I've experienced that is not a likely response because one could normally say "I have done that.” Present perfect is also used for past experience, so there's no need of saying, "I've experienced that,” whereas "I've had that experience" has some nuance.

Friend: Have you ever flirted with a female cop?      Me: Nope.      Friend: I have done that experience.   I think experience is the wrong word here. What else should he have said?


am travelling to USA via Kuwait and the layover is 5 hours.  I am Indian citizen and have valid USA Visa B1/B2 valid for the next 7 years.  Please update me I have to book a flight and need some help.

I am an Indian national and passport holder, traveling from New Delhi to Frankfurt (via Kuwait) and back with Kuwait Airways. I see no Terminal change for the onward and return journeys. I have no plans to leave the airport due to short layovers.  Do I need a Kuwait transit visa?


can be "upcasted" (cast using a higher spell slot) to target more creatures.  Does the caster choose which effect to apply for each target, or are the same effects applied to each target?

If a caster uses a higher level slot for the Enhance Ability spell, can they specify different effects for different targets?  Example: target 1 gets Bear's Endurance, and target 2 gets Bull's Strength.


Though it seems to be very simple question but I want help where I am lacking.Two charges say one of 10C and other of 1C how can they exert same force.Say a charge of ten coloumb will surely attract or repel the charge of 1C with 10 times.Also keep that mass is same.

If you have two point charges one being 1 Coulomb and the other being 1 Trillion Coulomb, it is said that the electric force from the 1 Coulomb point charge exerted on the 1 trillion Coulomb point charge is equivalent to the electric force from the 1 trillion coulomb point charge exerted on the 1 Coulomb point charge.  How can a 1 coulomb point charge exert the same force as a 1 trillion coulomb point charge?


I was able to insert two rows by the following query. What should I do to insert more rows into it?  insert into friend_name(      friend_id,       first_name,       middle_name,       last_name) select        3,      'rich',      'mond',      'hill'  from dual union all select       4,      'monunica',      'bellu',      'cia'  from dual


prove：  $\left|x+\frac{1}{x}\right|\geq 2$  Can I just use   $\left|\left(\sqrt{x}\right)^2+\left(\frac{1}{\sqrt{x}}\right)^2\right|\geq 2$  and  $\left|\left(\sqrt{-x}\right)^2+\left(\frac{1}{\sqrt{-x}}\right)^2\right|\geq 2$?

I was asked to prove that:   $$x + \frac{1}{x}\geqslant 2$$  for all values of $ x > 0 $  I tried substituting random numbers into $x$ and I did get the answer greater than $2$. But I have a feeling that this is an unprofessional way of proving this. So how do I prove this inequality?


I need to select the largest feature within another feature using Arcmap 10.3.  I have two sets of data, building footprints and land parcels. Generally there is a many to one relationship where there are many building footprints within one land parcel.   I would like to select the building footprint with the largest floor area in each land parcel. Resulting in a one to one relationship.   As I am working with 7000 building footprints and 5000 land parcels, I would like to find a way to automate this however I do not have a lot of knowledge on scripting. I can use ModelBuilder.  Below is an example of the data. Building footprint pink and land parcels black:

First, I have a shapefile consisting of square grids and each grid has an ID. Second, I have a shapefile consisting of different zones (with IDs).  A grid ID in the first shapefile can contain many zone IDs from the second shapefile.  I want to know what is the dominant zone ID inside a grid and record that in a table. I only want to know the dominant zone (in terms of the area) and not the rest of the zones intersecting that grid. In the end, I would want a 2-column table with all the grid IDs in the first column and the corresponding dominant zone ID (or the largest zone in terms of area) in the second column.  Here is a sample figure.  By just looking at the figure, I could tell that in Grid ID 1, the dominant zone/area is Zone ID 1.  In Grid ID 2, the dominant zone/area is Zone ID 2.  And in Grid ID 3, the dominant zone/area is Zone ID 3.  I would like to have a table with two columns, with each grid showing only the ID of the dominant area.


It is suggested to normalize data as 0 mean and 1 variance. Also, TanH considered better than Sigmoid activation function as it has 0 mean. Why 0 mean is important?

I see that lots of machine learning algorithms work better with mean cancellation and covariance equalization. For example, Neural Networks tend to converge faster, and K-Means generally gives better clustering with pre-processed features. I do not see the intuition behind these pre-processing steps lead to improved performance. Can someone explain this me?


I don't want to burn a CD, DVD or USB memory stick. And I don't care about saving the existing operating system (Linux Mint). I want to install Ubuntu (actually Kubuntu 12.04 LTS) to the computer directly from the ISO image. The image is for the Kubuntu Live DVD (3.5 GB).  The computer is now booted into Linux Mint. A set of command line steps would be satisfactory. In my mind, I simply need to trick the existing system into thinking I inserted a CD/DVD, right?  I know there is a similar question already but it does not have a good answer. The answer basically says, "see this link." I reviewed the link and I decided that StackExchange needs a good answer to this question. Furthermore, most answers at other places on the Internet assume the user is coming to Ubuntu from Windows. So I think this question is one that needs a good answer here. Thanks

I want to mount the contents of a boot-able CD image, like Ubuntu rescue remix, to a partition of the hard drive.  So I can have an entry in Grub to boot to the contents of that disk,  , details a similar process used for a Knoppix CD. Is there a way to do this for Ubuntu disks.


If $m=a_1x+b_1y$, $n=a_2x+b_2y$ and $a_1b_2-a_2b_1=1$, then prove that $\mathrm{GCD}(m,n)=\mathrm{GCD}(x,y)$  May I get a hint, please?

Problem:     If $(k,l) = 1$, show that $(b_2k-b_1l, a_1l-a_2k) = 1$ for $a_1b_2-a_2b_1=1$   Note: ($a_1, a_2,b_1,b_2,k,l \in \mathbb{Z}$)   Also note that the actual (bigger) problem is:     If $m = a_1x+b_1y$ (Eq1) and $n=a_2x+b_2y$ (Eq2) and $a_1b_2-a_2b_1=1$, prove that $(m,n)=(x,y)$.   I have proved that $(m,n) = d | x \text{ and } d|y$ I am left to prove that $d = (x,y)$, that's why I asked above question.  I had made $m = dk$ and $n = dl$ ($\therefore (k,l)=1$) and after substitution in Eq1 and Eq2 for $x$ and $y$ values I got $d(b_2k-b_1l)=x$ and $d(a_1l-a_2k) = y$. If I can show  $(b_2k-b_1l, a_1l-a_2k) = 1$ then definitely $d = (x,y)$  Method:  Suppose $(b_2k-b_1l, a_1l-a_2k) = d > 1$. Then, $d | b_2k, d | b_1l, d|a_1l,d|a_2k$ must be true.  This implies $d|a_2b_1kl$ and $d|a_1b_2kl$ must be true. Let, $dp = a_2b_1kl \implies a_2b_1 = \frac{dp}{kl}$ and $dq=a_1b_2kl\implies a_1b_2 = \frac{dq}{kl}$  So, $$a_1b_2-a_2b_1=1 \implies \frac{d(q-p)}{kl}=1 \implies kl =d(q-p)$$  I am stuck here. How to prove a contradiction so that $d = 1$?


Jawa asked me this  and I didn't know the answer. So I present it to the meta SO community:     [To get the Yearling badge] Do you need to earn the 200 rep within that one year or is it enough to get 200 at some point after being a member for a year? And does 'a year' mean the very first 12 months or the last (sliding window of) 12 months?    I would assume that if you hit 200 reputation after you've already been around for a year, then you would get the Yearling badge. But I don't know.

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


After changing my engine to biber from bibtex to ensure my bibliography worked, it no longer recognises my cross-references to labelled equations and theorems in my script. They are labelled and referenced as follows:  ...\label{equation}... ...\ref{equation}...   When I typeset in LaTeX the console reads as:  ...LaTeX Warning: Reference 'FactCor' on Page 28 undefined on input line 748... ...Package inputenc Error: Unicode char \u8:ï¿œ not set up for use with LaTeX

I'm trying to put a bibliography in my LaTeX document, but I get various errors when I run it in BibTeX (saying no \citation found etc.), and no bibliography is printed in the PDF when I typeset it in LaTeX. My code reads as follows:  \documentclass[12pt]{report} ... \usepackage{biblatex} \addbibresource{SUSYBib.bib} ... \begin{document} ...\cite{1}... ...\cite{2}... \nocite{*} \printbibliography \end{document}   And my .bib file reads as  @book{1, title={The Schrödinger Equation}, author={F. A. Berezin, M. A. Shubin}, year={1983}, publisher={Moscow State University, Moscow}, pages={57-59} } @book{2, title={An Introduction to Measure Theory}, author={Terence Tao}, year={2011}, publisher={American Mathematical Society}, pages={91} }


Prove that for any g(x) in a $\mathbb{Z}/p\mathbb{Z}[x]$ field, the degree of $\gcd{(x^p-x,g(x))}$ is equal to the number of distinct roots of g(x) First of all, I am assuming that the "number of distinct roots" refer to the number of distinct roots of g(x) in the mod p field Secondly, where should I start to go about proving this?

For any $g$ in $\mathbb{Z}/p\mathbb{Z}[x]$ prove that the degree of $f = \gcd(x^p - x, g(x))$ is exactly the number of distinct roots of $g$ in $\mathbb{Z}/p\mathbb{Z}$.   My main problem is that I do not really understand how to approach this problem at all. I am very new to solving proofs and any type of help would be appreciated thank you.


The airline is Oman Air. I tried 3 times to buy the ticket with my Capital one 360 and it failed everytime. So I had to use privacy.com as a last resort. My flight is in two days and now I received an email that after reviewing the transaction they need me to bring the physical card. Has anyone experienced something like this before like using a virtual visa card and what happened. I am so worried because my flight is categorically non-refundable.

I booked a flight for myself using my virtual credit card. It is a totally legit VISA card to my name from a bank in the departure country. However, it is totally virtual.  Now, after the payment, there is a message from the airline (Laos airlines) that says that I must present the physical credit card in order to check-in. However, I do not have any physical credit card, as it is a virtual one.  I contacted the bank and they said they are sorry and they cannot provide any document to the airline proving that I am the owner of the card.  The airline said they are sorry, if I will not present the card at the counter I cannot check-in. They also refused to reimburse me the flight so that I could buy it with another card (physical).  Do you have any ideas on how to go ahead?


How, in Python, could I add an object with a specified number of vertices n, all of which are at, say, the origin (0,0,0)?

I would like to create a mesh, then interactively add vertices (afterwards, possibly through a loop) to it through python.  Is that possible?  I can't find enough info from other answers to really get this going - either I find out how to create a mesh, or how to add a vertex, but can't seem to put them together in to a script.


So I was trying to create a bootable USB to reinstall Windows for a friend, but mistakenly started partitioning the wrong disk (probably the dumbest mistake I could have made).  This disk is a 1 TB WD Black in NTFS format, hooked up as my D: drive to Windows for a variety of photos, documents, movies and game installs – the basic home stuff.  There was about 400 GB of files on the drive (i.e., it was about 40% full).  The following sequence of events occurred:  diskpart select disk 1 // wrong disk number clean create partition primary select partition 1 active format fs=ntfs // note the missing 'quick' argument   It then ran to about 3% when I realized my mistake.  So I hit Ctrl+C to cancel the formatting.  In Windows' disk management tool the drive now shows up as healthy, active, primary NTFS partition that is 100% free and 931 GB capacity.  So after some googling, I downloaded . I tried analyzing and then the deeper analysis of the drive, which just came back with 1 available partition that is fully empty. The only files found were within the "System Volume Information" folder. It didn't seem to be able to restore any MFT copies or lost partitions, but I'm not an expert with these things so maybe I did something wrong – I wasn't sure exactly what guides and steps to follow since I did more than a simple diskpart clean.  After all that failed me, I attempted running PhotoRec to see if any files could be found. That also failed with 0 files found.  I'm out of ideas now, but from my (limited) knowledge, at most 3% of the drive was re-written in the format, so the rest of the drive should have intact data that can be recovered. What more can I try?  Update: Using Frhed, a hex editor, to load up the partition gave "A disk read error occurred...BOOTMGR is compressed" (image below). Trying to scroll through the sectors everything shows 0 – but without a boot sector, it can't be read so is this reliable?  Update 2: according to  on Tom's Hardware forum, using Ctrl+C to interrupt the command doesn't actually stop the formatting, it runs in a separate process in the background. Since I didn't immediately reboot my PC it has indeed overwritten the entire disk. Thanks for all the help, I wouldn't have needed to ask this question if I had known this sooner.

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


I am trying to create a bipartite graph using tikz, however, it doesn't seem to recognize the keys fsnode and ssnode on my Windows MiKTeK installation (works fine in Ubuntu).   Line:  \foreach \i in {$a$,$b$,$c$,$A$,$B$}   \node[fsnode,on chain] (f\i) [label=left: \i] {};   Error: ! Package pgfkeys Error: I do not know the key '/tikz/ssnode' and I am going toignore it. Perhaps you misspelled it.See the pgfkeys package documentation for explanation.Type H  for immediate help.... }

I want to draw something similar to this in latex. How can I do it? I want it to be a directed graph and want to be able to label the vertices.


We have just started using QGIS on windows at my work and I am the application responsible. I want my users to have a predefined setup with a couple of extensions and some WMS servers as a starting point. (If they want to add something afterwards, that's fine with me)  How do I do this?   I would prefer not to send out a description with open this menu and do that.   Is it possible to distribute some qgis-project or some type of .ini or .reg file with this information?

Are there any recommendations to manage and deploy various settings in QGIS (GUI-settings like visible plugins/toolboxes etc., settings in options, print compositions ...) to hundreds of clients / users?  Automated software installation is done so far (), but this comes with a standard configuration of the gui, which has by far too many options for a normal user, who only wants to see and print spatial data.


The eigenstates for the infinite potential well described by the Hamiltonian  $$ \hat{H}= \frac{\hat{P}^2}{2m} + V(x),\, V(x) = \begin{cases} 0,  & \text{if $x <0$} \\ \infty, & \text{if $x>L$} \end{cases} $$ are $$\Psi_n(x) = \sqrt{\frac{2}{L}}\sin\left(\frac{n\pi x}{L}\right)$$  Now, if two operators $\hat{A},\hat{B}$ commute, they have eigenstates in common. $\hat{H}$ and $\hat{P}$ commute but they do not have simultaneous eigenstates. Why?

This is inspired by Griffiths QM section 2.2, on the infinite square well, which is about how far I've gotten (so, sorry if this is addressed later in the book).  For any given starting wavefunction, you can express it as a sum over the solutions of the time-independent Schrödinger equation. The coefficients in the sum are constant in time, therefore the expectation value of energy is constant in time. The chapter says "this is a manifestation of conservation of energy in quantum mechanics." Ok.  Now in problem 2.5, we have a wavefunction that is an even mixture of the first two stationary states. Part D has us compute the expectation value of momentum, and the solution is sinusoidal in time. So momentum is not conserved.  How can momentum be not conserved? Why is energy conserved but not momentum?


I need to write a method to calculate the average of an unknown type of numbers (double, float, int...). I tried to do something like this, but it works for double type only:  double average(void *arr, int length, int bytes) {     int i;     double sum = 0;     double num;     for (i = 0; i < length; i++) {         memcpy(&num, (char *) arr, bytes);         sum += num;         arr = (char *) arr + bytes;     }     return sum / length; }   Any suggestions?

Is there any way to achieve function overloading in C? I am looking at simple functions to be overloaded like    foo (int a)   foo (char b)   foo (float c , int d)   I think there is no straight forward way; I'm looking for workarounds if any exist.


I'm experimenting using Mosh instead of raw SSH for remote shell connections. So far I like it, but I've become used to being able to page-up or scroll through backscroll in my terminal window to see the results of older commands or commands that print too much info to fit in a single window. This works fine with normal SSH connections, but Mosh seems to be "eating" lines beyond the height of the window, so when I scroll back all I can see is stuff printed before I invoked Mosh. Is there a way I can get Mosh to behave like raw SSH and retain the backscroll?  If it matters, the client is running on OS X Mountain Lion (10.7) in the standard "Terminal" program, with tcsh.

Is there a way to use  without giving up the local scrollback?  Basically, in some circumstances, IP-roaming is indeed useful and needed, but the extra terminal emulation and key prediction seems to only be getting rid of the local scrollback buffer lines and the session history.


I know there's an order to the games, but are their stories built off of each other or are they separate?

I've got the original Assassin's Creed game somewhere in my house. When I finish a game I then intend to play it, but it seems to "move" and so I begin another game instead. Been going on for two years+.  My question is, should I bother with the first Assassin's Creed game? I know there are a lot more out there now. Will I miss a lot of the story if I were to jump straight to the second game? Or Unity?  Should I begin from the first game or are the later ones so much better that missing some of the story does not matter?


How to replace these symbols "ąčęėįšųūž" with these symbols "aceeisuuz" in javascript? I know I need to use regex, but I can't make pattern.  this is what I have  var string = $(this).val();         string = string.replace(/\s+/g, '-').toLowerCase();         string = string.replace(/[^a-zA-Z0-9-]/g,'_');         string = regExp something here...      $("#custom_url").val(string);   UPDATE:  found this solution in other thread:  function convert_accented_characters(str){     var conversions = new Object();     conversions['ae'] = 'ä|æ|ǽ';     conversions['oe'] = 'ö|œ';     conversions['ue'] = 'ü';     conversions['Ae'] = 'Ä';     conversions['Ue'] = 'Ü';     conversions['Oe'] = 'Ö';     conversions['A'] = 'À|Á|Â|Ã|Ä|Å|Ǻ|Ā|Ă|Ą|Ǎ';     conversions['a'] = 'à|á|â|ã|å|ǻ|ā|ă|ą|ǎ|ª';     conversions['C'] = 'Ç|Ć|Ĉ|Ċ|Č';     conversions['c'] = 'ç|ć|ĉ|ċ|č';     conversions['D'] = 'Ð|Ď|Đ';     conversions['d'] = 'ð|ď|đ';     conversions['E'] = 'È|É|Ê|Ë|Ē|Ĕ|Ė|Ę|Ě';     conversions['e'] = 'è|é|ê|ë|ē|ĕ|ė|ę|ě';     conversions['G'] = 'Ĝ|Ğ|Ġ|Ģ';     conversions['g'] = 'ĝ|ğ|ġ|ģ';     conversions['H'] = 'Ĥ|Ħ';     conversions['h'] = 'ĥ|ħ';     conversions['I'] = 'Ì|Í|Î|Ï|Ĩ|Ī|Ĭ|Ǐ|Į|İ';     conversions['i'] = 'ì|í|î|ï|ĩ|ī|ĭ|ǐ|į|ı';     conversions['J'] = 'Ĵ';     conversions['j'] = 'ĵ';     conversions['K'] = 'Ķ';     conversions['k'] = 'ķ';     conversions['L'] = 'Ĺ|Ļ|Ľ|Ŀ|Ł';     conversions['l'] = 'ĺ|ļ|ľ|ŀ|ł';     conversions['N'] = 'Ñ|Ń|Ņ|Ň';     conversions['n'] = 'ñ|ń|ņ|ň|ŉ';     conversions['O'] = 'Ò|Ó|Ô|Õ|Ō|Ŏ|Ǒ|Ő|Ơ|Ø|Ǿ';     conversions['o'] = 'ò|ó|ô|õ|ō|ŏ|ǒ|ő|ơ|ø|ǿ|º';     conversions['R'] = 'Ŕ|Ŗ|Ř';     conversions['r'] = 'ŕ|ŗ|ř';     conversions['S'] = 'Ś|Ŝ|Ş|Š';     conversions['s'] = 'ś|ŝ|ş|š|ſ';     conversions['T'] = 'Ţ|Ť|Ŧ';     conversions['t'] = 'ţ|ť|ŧ';     conversions['U'] = 'Ù|Ú|Û|Ũ|Ū|Ŭ|Ů|Ű|Ų|Ư|Ǔ|Ǖ|Ǘ|Ǚ|Ǜ';     conversions['u'] = 'ù|ú|û|ũ|ū|ŭ|ů|ű|ų|ư|ǔ|ǖ|ǘ|ǚ|ǜ';     conversions['Y'] = 'Ý|Ÿ|Ŷ';     conversions['y'] = 'ý|ÿ|ŷ';     conversions['W'] = 'Ŵ';     conversions['w'] = 'ŵ';     conversions['Z'] = 'Ź|Ż|Ž';     conversions['z'] = 'ź|ż|ž';     conversions['AE'] = 'Æ|Ǽ';     conversions['ss'] = 'ß';     conversions['IJ'] = 'Ĳ';     conversions['ij'] = 'ĳ';     conversions['OE'] = 'Œ';     conversions['f'] = 'ƒ';      for(var i in conversions){         var re = new RegExp(conversions[i],"g");         str = str.replace(re,i);     }      return str; }

For a poor man's implementation of near-collation-correct sorting on the client side I need a JavaScript function that does efficient single character replacement in a string. Here is what I mean (note that this applies to German text, other languages sort differently):  native sorting gets it wrong: a b c o u z ä ö ü collation-correct would be:   a ä b c o ö u ü z  Basically, I need all occurrences of "ä" of a given string replaced with "a" (and so on). This way the result of native sorting would be very close to what a user would expect (or what a database would return). Other languages have facilities to do just that: , in , , . But what about JavaScript? Here is what I have right now. // s would be a rather short string (something like  // 200 characters at max, most of the time much less) function makeSortString(s) {   var translate = {     "ä": "a", "ö": "o", "ü": "u",     "Ä": "A", "Ö": "O", "Ü": "U"   // probably more to come   };   var translate_re = /[öäüÖÄÜ]/g;   return ( s.replace(translate_re, function(match) {      return translate[match];    }) ); }  For starters, I don't like the fact that the regex is rebuilt every time I call the function. I guess a closure can help in this regard, but I don't seem to get the hang of it for some reason. Can someone think of something more efficient?  Answers below fall in two categories:  String replacement functions of varying degrees of completeness and efficiency (what I was originally asking about) A  of  , which is now  among JS engines (not so much at the time of the question) and could solve this category of problem much more elegantly.


I am a U.S. citizen and have a overnight layover in Frankfurt Airport. Can I leave the airport for a night out in the city and then come back? Do I need a specific travel visa?

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


After participating in my first moderator election, I was wondering what the reason was for displaying the number of other users' votes cast. In my opinion, that can skew personal opinions of voters before they vote, perhaps making the election unfair to candidates that do not have a strong start.  Why are votes displayed in a moderator election instead of blind voting?

I find that my expectations of a nominated person and where my votes should go are affected by what number I see next to them, even if I don't want it to. I feel I gravitate towards nominees who already have a larger number of votes, and away from ones with smaller.  Is there a benefit to this that I'm missing?


Can I mix up dough today, refridgerate overnight in bowl, then bring to room temperature and continue the rising, shaping the next day?

I do not have enough time to bake my bread.  Can I refrigerate it or let it sit on the counter and bake it later in the day?


I definitely think I've removed the virtual box perfectly. However, the following problems arise.  Hit:1 http://uk-mirrors.evowise.com/ubuntu focal InRelease Hit:2 http://uk-mirrors.evowise.com/ubuntu focal-updates InRelease Hit:3 http://uk-mirrors.evowise.com/ubuntu focal-backports InRelease Hit:4 http://uk-mirrors.evowise.com/ubuntu focal-security InRelease Hit:5 https://dl.winehq.org/wine-builds/ubuntu focal InRelease                  Ign:6 http://download.virtualbox.org/virtualbox/debian focal InRelease          Err:7 http://download.virtualbox.org/virtualbox/debian focal Release   404  Not Found [IP: 104.70.236.28 80] Reading package lists... Done E: The repository 'http://download.virtualbox.org/virtualbox/debian focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   $ sudo apt update  Even if I use the Ubuntu software update app, not the terminal, a system message of failure occurs. I tried to change to a best update server, but it also failed.    A similar question case has been reviewed, but no related case has been found with Virtual Box.    For reference, there are still two virtual boxes of related installation files left, but these could not be removed with the dpkg command.  Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name                     Version      Architecture Description +++-========================-============-============-========================> un  virtualbox-guest-dkms    <none>       <none>       (no description availabl> un  virtualbox-guest-modules <none>       <none>       (no description availabl>

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


I am looking at a very old code-base, and every field access follows this pattern:  void method() {   TYPE fieldRef = this.field;   // Use fieldRef instead of field }   I can't figure out why this pattern is followed rigorously. Is there some performance benefit to this? Does it have something to do with how fields behave with inheritance?

When referencing class variables, why do people prepend it with this? I'm not talking about the case when this is used to disambiguate from method parameters, but rather when it seems unnecessary.  Example:  public class Person {             private String name;      public String toString() {         return this.name;     } }   In toString, why not just reference name as name?  return name;   What does this.name buy?   a stackoverflow question whose code has this pre-pending.


Software: QGIS 2.18.19 Spreadsheet: Office Libre 5.3.4.2 GitHub Link:     Update 1 @ben-w I turned on Toggle Editing. When I tried to change datatype, I get error     Original Question I wish to change datatype of column BBL of Bklyn_BBL.zip (the .dbf file) from Decimal to Whole Number. When try in Office Libre I keep getting errors when I save  The QGIS Attribute table is not editable  Then went to QGIS I tried downloading Table Manager plugin to edit the attributes but I cannot find it under Processing > Toolbox Please guide.

I have seen a solution that I don't get to work - I need to change data type from string to integer and I did what is shown i the image below Can someone point out what I do wrong?


Could someone help me to prove this inequality using the induction method?  $n \in\mathbb{N}$ (Naturals)  $$\frac{1}{\sqrt{1}}+\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{3}}+\ ...\ +\frac{1}{\sqrt{n}}\geq\sqrt{n}$$  I did the basis step ($n=1$), but I got stuck at the second step (induction step).  All help is appreciated!

$$\dfrac{1}{\sqrt 1}+\dfrac{1}{\sqrt 2}+\dfrac{1}{\sqrt 3}+\cdots+\dfrac{1}{\sqrt n}\geq \sqrt n$$ I want to prove this by Induction  $$n=1 \checkmark\\ n=k \to \dfrac{1}{\sqrt 1}+\dfrac{1}{\sqrt 2}+\dfrac{1}{\sqrt 3}+\cdots+\dfrac{1}{\sqrt k}\geq \sqrt k\\ n=k+1 \to \dfrac{1}{\sqrt 1}+\dfrac{1}{\sqrt 2}+\dfrac{1}{\sqrt 3}+\cdots+\dfrac{1}{\sqrt {k+1}}\geq \sqrt {k+1}$$ so $$\dfrac{1}{\sqrt 1}+\dfrac{1}{\sqrt 2}+\dfrac{1}{\sqrt 3}+\cdots+\dfrac{1}{\sqrt k}+\dfrac{1}{\sqrt {k+1}}\geq \sqrt k+\dfrac{1}{\sqrt {k+1}}$$now we prove that $$\sqrt k+\dfrac{1}{\sqrt {k+1}} >\sqrt{k+1} \\\sqrt{k(k+1)}+1 \geq k+1 \\ k(k+1) \geq k^2 \\k+1 \geq k \checkmark$$ and the second method like below ,   and I want to know is there more Idia to show this proof  ? forexample  combinatorics proofs  , or using integrals ,or fourier series ,....    Is there a close form for this summation ?  any help will be appreciated .


I am searching for a downloadable database of administrative boundary shapes, best would be worldwide data.  I have found  but it seems a bit outdated, also the  seems interesting but I haven't found any exports based on this definition.  The detail level of the shapes is not that important as it would be used to let a user select the city/region (if not in a city or no data for that city available). A hierachical representation like Country > Region > City would be great.

After learning about the  datasets I've working with the following layers, from the USA data   Country boundaries State boundaries County boundaries City boundaries ZipCode/Postcode boundaries   What I am trying to find is the equivalent (where appropriate) of the same data for various countries.  Is there any free administrative boundaries available as shapefiles for other countries?


In my java project, I have a private HashMap field (eggs is an enum, bacon is an object that has an ArrayList field). So it's something like:      class Foo {        private HashMap<Eggs, Bacon> breakfast;         foo() {          this.breakfast = new HashMap<Eggs, Bacon>();}         void setValues(int x) {           ArrayList<Integer> temp;           Bacon b;           for(int i = 0; i < x; i++) {              temp.add(i);}           b = new Bacon(temp);           this.breakfast.put(Eggs.Scrambled, b);}     }   Essentially, even if I make sure to call setValues first in my testClass, a call to breakfast.get() or breakfast.size() will always result in a NullPointerException. In my actual code I have several enum to object mappings in for loops. Using the debugger, I found that the values were set but immediately vanished at the end of each loop. I have no idea why my HashMap field isn't saving the values that get put into it. Even when I changed the field to an ArrayList and set or added values, I'd still get the same nullpointer/outofbounds exception  I can post my actual code if needed but I was wondering if anyone had any insight to this. I'm at my wit's end

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


So I noticed that while my pokemon is defending a gym, it can evolve (or looks like it could since the button is not faded out). You can tell it is in the gym because the team insignia is on the CP circle.    Has anyone tried this? Does my Caterpie become a Metapod at the gym or does it stop me from evolving?

I just dropped my Vaporeon off at the gym, but to my surprise, he can still be viewed in my Pokémon list! The buttons are there to level him up, but I'm not gonna be able to get any Eevee candy for a few hours to try. Can I level him up while he's in the gym?


Google has started punishing non https sites both in SEO and their browsers. So I guess we must make sure that all our clients are using https    Assuming that I have a domain example.com I would like to redirect all the variations of this domain to the https version.   There can be six variations example.com, www.example.com, http://example.com, http://www.example.com, https://example.com, https://www.example.com.   I want to make sure that all these variations redirect to https://www.example.com.

In Drupal 7, I used the Secure login module to run the site on a secure connection, but it seems it doesn't revert back to http on logout. I would like to just run the whole site as https:// as a simplification.  Is there a simple way to do this without the use of module?


I want the output to be XOllo, but segfault is what I am getting.  #include <stdio.h> #include <string.h>  int main(){    char *buf="hello";   char *xys="XO";    while(*buf != 'l'){   *buf = *xys;   xys++;   buf++;   }   printf("%s \n", buf);   return 0; }   o/p-: segfault   I need the o/p as XOllo, but I get seg fault. Please suggest.   Please suggest.

Possible Duplicate:          I want to write a function that reverses the given string passed into it. But, I can not. If I supply the doReverse function (see code below) with a character array, my code works well.  I can't figure out why this does not work. I am able to access str[0] in doReverse, but I can't change any value of the array by using a char pointer. Any ideas?  void doReverse(char *str) {     str[0] = 'b'; }  void main(void) {     char *str = "abc";     doReverse(str);     puts(str); }   Update:  I know how to do write a reverse function by passing a character array to it:  void reverse1(char p[]) {     int i, temp, y;      for (i = 0, y = strlen(p); i < y; ++i, --y) {         temp = p[y-1];         p[y-1] = p[i];         p[i] = temp;     } }   But, I want to write another version that gets a char pointer as a parameter.


Let $V$ be a vector space. For any set $S\subset V$, we define $S^0=\{f\in V^\ast\,:\, f(v)=0,\forall v\in S\}$. If $\dim V<\infty$ and $W_1,W_2\subset V$ are vector subspaces, then show that $W_1^0+W_2^0=(W_1\cap W_2)^0$.     I was able to show that $W_1^0+W_2^0\subset (W_1\cap W_2)^0$: Let $f\in W_1^0+W_2^0$. Then there are $f_i\in W_i^0$, $i=1,2$ so that $f=f_1+f_2$. If $v\in W_1\cap W_2$, then $f(v)=f_1(v)+f_2(v)=0$, since $v\in W_1$, $f_1\in W_1^0$ and $v\in W_2$, $f_2\in W_2^0$. Therefore $f\in (W_1\cap W_2)^0$.  I don't have any idea of how to do the converse inclusion!

Let $V$ be a finite dimensional vector space and $U^0$ and $W^0$ denote the annihilators of subspaces $U$ and $W$, respectively.  Then I need to show that $(U\cap W)^0 = U^0 + W^0$.  I can show that $U^0 + W^0 \subseteq (U\cap W)^0$ like so: Let $f\in U^0$ and $g\in W^0$.  Then, because $U^0, W^0 \subseteq (U\cap W)^0$, we see that if $f\in U^0$ and $g\in W^0$, then for any $v\in U\cap W$ and $a,b \in \Bbb F$, $(af+bg)(v) = af(v) + bg(v) = 0$.  Thus $af+bg\in (U\cap W)^0$.  But because $f$ and $g$ were arbitrary, this implies that any linear combination of elements of $U^0$ and $W^0$ is an element of $(U\cap W)^0$.  I.e. $U^0+W^0 \subseteq (U\cap W)^0$.  But I haven't had any luck proving the other direction.  Obviously I should start with $f\in (U\cap W)^0$.  But then it looks like I need to somehow break that function into two to show its in $U^0 + W^0$.  That's throwing me off.


How to prove this fact:      If $X \subset \mathbb{R}$ is finite, then the space of continuous functions $C(X)$ is finite dimensional (isomorphic to $\mathbb{C}^n$)?   Thanks for help!

I know that the vector space of all real valued continuous functions on a compact Hausdorff space can be infinite dimensional.  When will it be finite dimensional?  And how will I identify that vector space with $\mathbb{R}^n$ for some $n$?


Edit:  In my view this question is not a duplicate of the indicated question. I specifically want to also know what is the reason EHCI Hand off setting exists on XHCI motherboard where all USB ports are essentially controlled by XHCI. Thanks.  This question is close to  on SU. There OP wants to know what is the ideal setting for XHCI Handoff when running Windows 7. Should it be Enabled or Disabled. So while it partly addresses the issue I have two related questions independent of the OS installed.   What is the actual meaning of Handoff? On modern boards where (as per my understanding, see the below post quote from the manual) even USB 2.0 is wired to XHCI controller, what purpose does EHCI Handoff setting do?   The link on B350-DASH below shall open the Motherboard Manual. The exact description is also pasted below as a Quote.  The Gigabyte motherboard  has following options in BIOS Settings     XHCI Hand-off  Determines whether to enable XHCI Hand-off feature for   an operating system without XHCI Hand-off support. (Default: Enabled)      EHCI Hand-off  Determines whether to enable EHCI Hand-off feature for   an operating system without EHCI Hand-off support. (Default: Disabled)   Moreover it seems that it's the Chipset & CPU that handles the USB 3 ports on AM4 Platform.   So where does EHCI come in for EHCI Handoff?     USB      Chipset:   - 2 x USB 3.1 Gen 2 Type-A ports (red) on the back panel   - 2 x USB 3.1 Gen 1 ports available through the internal USB header   - 4 x USB 2.0/1.1 ports available through the internal USB headers      CPU:   - 4 x USB 3.1 Gen 1 ports on the back panel

I have a Jetway NF9E-Q77 motherboard which supports USB 3.0.  An Intel driver is available to enabled USB 3.0 support in Windows 7.  Assuming the driver is installed, should xHCI hand-off be enabled or disabled in BIOS setup?    The BIOS manual says this:    I know Windows 7 doesn't natively support USB 3.0. That being the case, it seems the setting should be enabled.  On the other hand, the Intel driver enables USB 3.0 support in Windows 7. That being the case, it seems the setting should actually be disabled.  Which one is correct?


I remember that once Nearly Headless Nick told Harry that souls find a chance to come back to the world or go the other way (or something like this). Those who choose to come back or have an unfinished business come back. For example, Moaning Mertyl came back as a ghost to haunt those who bullied her.  Many people in the Wizarding World has some unfinished business. They can come to fulfill those. Death Eaters like Bellatrix could come to get revenge.  So why isn't the Wizarding World filled with ghosts?

In Harry Potter and the Sorcerer's Stone, Nearly-Headless Nick and some other ghosts can visit the Hogwarts students, but why can't other deceased people - such as Harry's parents?


In haunt 28, the Traitor's Tome says:     The Revolver and other Speed attacks can't be used against the Demon Lord.   The Secrets of Survival book doesn't mention this. If a hero tries to make a speed attack against the Demon Lord, do they waste their attack, or do I have to tell them about this before they try?

This came up in a game involving Haunt 23, Tentacled Horror. (Spoilers will be kept to a minimum.) There are multiple different types of monsters in that Haunt: some of them have a Sanity trait, and others don't. One of the Heroes had the Ring, which let him attack with Sanity instead of Might. He attacked a monster that had a Might trait, but no Sanity trait, using the Ring. At the time, I told him that the monster had no Sanity trait and that he'd need to try a different type of attack, and he ended up doing a Might attack using the Sacrificial Dagger instead.  Was this the right thing to do, or should the initial attack have failed entirely? Or should we have explained which traits the monster does and doesn't have the instant the monster went on the map? The rules just say "you can't use a trait to attack against a monster that doesn't have that trait," but it's unclear on how to handle the attempt. This is particularly vexing, because all monsters have hidden traits and this is going to come up again.  (I looked at the , and it turns out that the specific Haunt I was looking at no longer has that problem, but I'm sure this question will still apply to other monsters.)


I need to produce the following BibLaTeX style:    Note that at the beginning we have only the first author (last name and then initials), then an article title, and only then a list of all authors (initials and then last name).  How do I enter the list of multiple authors in the .bib file properly and how to include it in the main .tex file?  Any help would be really appreciated.

I'm using biblatex for my references, and "main author's name" and "all authors names" should have been separated from the article's title as follows:   I've tried to add custom field authors in .bib file, as below:  @article{Abd_2014,     author = {Abdullin A.A.},     authors = {Abdullin A.A. AND Drozdov V.N. AND Plotitsyn},     title = {Optimal Control System},     journaltitle = {Advances in Automatic Control},     date = {2014},     pages = {22-26} }   and then adding it to the preamble (I've read this in biblatex.pdf user manual file)  \DeclareBibliographyDriver{article}{     \usebibmacro{bibindex}     \usebibmacro{begentry}     \printnames{author}     \newunit\newblock     \printfield{title}     \newunit\newblock     \printfield{authors} % \printnames or \printlist didn't help either     \newunit     \printfield{journaltitle}     \newunit     \printfield{year}        \newunit     \printfield{pages}           \usebibmacro{finentry} }   But all that I've got is:   I need to get rid of the appeared indentation, as well.  Here is the whole .tex file  \documentclass[twoside, final, 10pt]{extreport}  \usepackage{extsizes} \usepackage{mathtext} \usepackage{cmap} \usepackage[T2A]{fontenc} \usepackage[english,russian]{babel} \usepackage[utf8]{inputenc} \usepackage{pscyr}  \usepackage[a5paper,left=2.5cm,right=1.5cm,top=2cm,bottom=2cm]{geometry}  \usepackage[maxbibnames = 99, sorting = nyt, style = numeric-comp, backend = biber, bibencoding = utf8]{biblatex} \DeclareFieldFormat{labelnumberwidth}{#1\adddot} \DeclareFieldFormat[article]{title}{\textit{#1}} \DeclareFieldFormat[article]{pages}{C. #1} \DeclareFieldFormat[article]{journaltitle}{#1} \renewbibmacro{in:}{\ifentrytype{article}{}{\printtext{\bibstring{in}\intitlepunct}}}  \AtBeginBibliography{     \renewcommand*{\finalnamedelim}{%         \ifnumgreater{\value{liststop}}{2}{}{}\space} }  \DeclareBibliographyDriver{article}{%     \usebibmacro{bibindex}%     \usebibmacro{begentry}%     \printnames{author}%     \newunit\newblock     \printfield{title}%     \newunit\newblock     \printfield{authors}%     \newunit     \printfield{journaltitle}%     \newunit     \printfield{year}%     \newunit     \printfield{pages}%           \usebibmacro{finentry} }  \begin{filecontents}{\jobname.bib}     @article{Abd_2014,         author = {Abdullin A.A.},         authors = {Abdullin A.A. AND Drozdov V.N. AND Plotitsyn},         title = {Optimal Control System},         journaltitle = {Advances in Automatic Control},         date = {2014},         pages = {22-26}     } \end{filecontents} \addbibresource{\jobname.bib}  \usepackage[unicode, hidelinks]{hyperref}  \begin{document}     \nocite{*}       \printbibliography[heading = bibintoc, title = ЛИТЕРАТУРА] \end{document}


I have my son's laptop.  He passed away this year and I am trying to access his computer.  I dob't have the password or the email address he used.  It is asking me for an authentication code when i try to go in as administrator.    Can you help me?

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


Consider the ring  $R = \mathbb{Z}_6[x]/\langle2x+4\rangle$ . Which of the following are true?   $R$ has infinitely many elements. $R$ is a field. $5$ is a unit in $R$. $4$ is a unit in $R$.   I know that $R = \mathbb{Z}_6[x]/\langle2x+4\rangle = \{f(x)+\langle2x+4\rangle\mid f(x)\in{\mathbb{Z}_6[x]}\}$ and that $(2x+4) + \langle2x+4\rangle = 0+ \langle2x+4\rangle$, which implies $x=-2$ in $R$.  also $\mathbb{Z}_6$ is not field and $(2x+4) = 2(x+2)$ is reducible in $\mathbb{Z}_6[x]$ (also $2x+4$ has a zero in $\mathbb{Z}_6$).  I know that if I will prove that R is not ID then it is not field but I am not getting any direction  Please give me some direction.

Let $R$ be the ring obtained by taking the quotient of $\mathbb{Z_6}[X]$ by principal ideal $(2X+4)$. Then  1) $R$ has infinite elements  2) $R$ is field  3) $5$ is unit in $R$  4) $4$ is unit in $R$.  My Attempt:  \begin{equation*} \mathbb{Z_6}[X]/(2X+4) = \mathbb{Z_6}[X]/(2(X+2)) = \mathbb{Z_3}[X],  \end{equation*} as $X+2$ has root in $\mathbb{Z_6}$. According to me 1) and 3) are correct but I'm not sure about my answer. Help me. I am not more familiar with polynomial and quotient ring. I searched this problem here but couldn't get this here. If this problem is already asked here then how can I get this?  Thank you in advance.


I remember something in The Deathly Hallows that Harry tries "Accio Hagrid" and the bike shoots towards Hagrid instead of the opposite thing that should occur. (Thanks Himarm for the quote)     “Hagrid!” Harry called, holding on to the bike for dear life. “Hagrid — Accio Hagrid!” The motorbike sped up, sucked toward the earth.    So what would happen if we said, let's say "Accio Eiffel tower" (Not Accio moon as it may cause death due to various factors :D ), assuming that we don't have enough power to summon such a big object. (I doubt only Dumbledore could manage that! ). Would we get sucked towards Eiffel tower as harry and the bike gets towards Hagrid. Wouldn't that then be a great way to travel? ( If we can somehow manage to prevent collisions, by putting some spell on ourselves or something?)

We know that Accio spell (aka ) has some limits:   It can be blocked (e.g. Harry couldn't Accio the Diadem in RoR in Deathly Hallows). Many more failures are listed on Wikia.   But what are the exact full rules and limitations governing the spell in Harry Potter world?   Distance?  Line-of-sight?  Knowing exact or approximate location?  Specificity of item (e.g. "Accio Broom" seemed to work for Weasleys in OotP to bring their locked-up brooms - why not just a random broom?) Types of Accio-able stuff? Can you Accio water? Lump of earth? Gases/liquids/etc...? Can you Accio based on jQuery selector (or an SQL where clause), for lack of a better description? E.g. "Accio the book that has the word 'Flammel'"? "Accio biggest green ball from this room"? Can you Accio ALL items of a kind? (the reason I thought of this whole question was seeing "Accio all guns" comment in ). Can you Accio vague stuff? ("Accio meal"). Other rules that can be inferred.   NOTE: While Wikia article has some of the info, it is clearly very lacking in details on specific rules based on specific instances in canon. I'm looking for a fully comprehensive, organized ruleset for the charm, not merely 1-2 tidbits in Wikia article.


I asked a question on Physics about an unproducible code, and it was close voted as not about physics: .  Since the nature of the question is about mismatched results with scientific theories not fixing bugs, I think Stack Overflow or Code Review are not a right place. Mathematics can work for common problems, but again not a good fit if it requires knowledge outside math. The last thing I can come up is Computational Science, which seems the right choice for algorithms, but . The question  assumes that I've coded correctly in principle.   Where can I ask such questions?

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


I have a list that I acquired parsing a text file(delimeted by \t and \n) which I eventually have to import into a database:  list = ['1', '1', 'Thurs', '1', 'Snow', '1', 'Rockville', 'Basic', 'Medium',  '1', 'Smith, J.', 'Junior', '5', '1', 'Chicken Noodle', 'Progresso',  'Canned', 'Basic', '1', 'Radio', 'Morning Drive', 'Weekday', '405.18''2',  '1', 'Thurs', '1', 'Snow', '1', 'Rockville', 'Basic', 'Medium', '1', 'Smith,  J.', 'Junior', '5', '2', 'Chicken Noodle', 'Campbells', 'Canned', 'Basic',  '1', 'Radio', 'Morning Drive', 'Weekday', '453.30' ..... list continues]   After each 23 items a new record starts. I though that what I need is to slice 4-5 items with a step of 23. So I am trying the following:  sliceN = slice(14-18) listSlice=list[sliceN:-1:23]   This doesn't work.  I would really appreciate any advise on solving my issue. If there are other better ways to approach it please let me know.

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I accidentally typed the command sudo chmod -R 0444 / now my system won't boot and when I click recovery mode, I get end kernal panic Attempted to kill init exit code=0x00000100.

I accidently ran  sudo chmod 755 -R /   instead of  sudo chmod 755 -R ./   I stopped it after few seconds, but now there is some problems such as  sudo: must be setuid root   How can I revert permissions back?


I'm working on a new blog that collects resources for web developers like lists of available CMS, Frameworks, Libraries and other plugins. I want to use the author description for every item as is from its website and telling that this is the author description and of course with a link back to that site where it will be available for download (not on my site).  Will I be infringing copyright or will my SEO be penalized for duplicating content maybe?  Here is an example of what a post will look like:

This is a general, community wiki question regarding duplicate content.  If your question was closed as a duplicate of this question and you feel that the information provided here does not provide a sufficient answer, please open a discussion on .     What does Google consider to be duplicate content? Will the way I am presenting my content result in a duplicate content penalty? How can I avoid having my site's content treated as duplicate content?


I want to know if (hypothetically) a star appears out of nowhere at a certain distance (say 20 light seconds) away from me, how long will it take for me to get the feel of it's gravity? Will I know it before it's light will reach me (20 seconds)? or after?

A thought experiment: Imagine the Sun is suddenly removed. We wouldn't notice a difference for 8 minutes, because that's how long light takes to get from the Sun's surface to Earth.   However, what about the Sun's gravitational effect? If gravity propagates at the speed of light, for 8 minutes the Earth will continue to follow an orbit around nothing. If however, gravity is due to a distortion of spacetime, this distortion will cease to exist as soon as the mass is removed, thus the Earth will leave through the orbit tangent, so we could observe the Sun's disappearance more quickly.  What is the state of the research around such a thought experiment? Can this be inferred from observation?


I own Nikon D90 with a 18-105mm kit lens. I have been looking for a suitable lens for birding with D90. According to Nikon support  would work with D90. But I guess 300mm is not enough for birding. So what alternative do I have?

Currently, the zoomiest lens I have is a Nikon 18-200mm. I want to be able to take photos of wildlife, or in most cases birds, which I can't do at 200mm.  For a long time, I wanted to purchase a Nikon AF VR 80-400mm f/4.5-5.6D ED. It is very small and weights nothing; it's also really cheap (approx. $1000). On the other hand, I suppose that the quality of this lens is not very good, especially at 350 to 400mm.  Nikon also has a big and heavy AF-S f/2.8G ED VR at +$9000, and an even larger and heavier AF-S 500mm f/4G ED VR at +$8000. Those two lenses are not a solution: they are too expensive for me, and their size and weight makes it impossible to take them in a bag for long walks.  Is there a lens somewhere between, compatible with Nikon D7000? In other words, is there a lens with a slightly better quality at 400mm or more (including fixed-length lenses) than a Nikon 80-400mm, but not as expensive as Nikon's 400mm and 500mm lenses and not as big and heavy?


I'm allowing language change feature inside my application. As user select new language feature inside the application I need to quit the application and user will have to start it again. For quitting I'll show an alert to user that you have to restart the application for language change to complete.  Now how can I use manual termination of iOS app and make it approve from Apple.  PS: Facebook do the same for language change. They tell the user that app needs to restart for language change to take place. Some other apps also kills the application on some alert tap.

I am programming an iPhone app, and I need to force it to exit due to certain user actions.  After cleaning up memory the app allocated, what's the appropriate method to call to terminate the application?


Here is my code:  if [ -f /Applications/xml[0-9].pl ]   I also tried with -f =~ and double brackets but none seem to work.  I first though that the regex might be faulty but I tried this.  echo h1 | sed 's/h[0-9]/h/'   And that worked. What am I doing wrong here?

I am trying to write an if statement to test whether there are any files matching a certain pattern. If there is a text file in a directory it should run a given script.  My code currently:  if [ -f /*.txt ]; then ./script fi   Please give some ideas; I only want to run the script if there is a .txt in the directory.


I've got some problems with the codification on my db.  Db and tables are set with utf8_general_ci, and all PHP web pages have some header with this encoding.  From FORM I've to insert something, that is perfectly shown on web page, but on db figures like : Ã weÃ rewÃ fÃ dsÃ fewÃ   After db connection I've made some:  $connection->set_charset("utf8_general_ci");   Someone can help me with this? Thank you everyone!!

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I have a script, written in python:  #!/usr/bin/python3 from tkinter import messagebox variable = messagebox.showinfo('title', 'question')   This python script does nothing else than showing a message box on my screen. I want to start that script whenenver I connect an usb drive to my computer.  So I created a new file 10-myself.rules in the directory /etc/udev/rules.d/.  KERNEL="sdb",RUN+="/usr/bin/python3 /home/user/projects/path_to_python.py"   But I do not see any message box when put the usb drive into my computer. Where is the error? How can I debug that?  I also called the command  udevadm control --reload-rules   And I tried to change the rule to  KERNEL="sdb*",RUN+="/usr/bin/python3 /home/user/projects/path_to_python.py"   or to the rule  KERNEL="sdb1",RUN+="/usr/bin/python3 /home/user/projects/path_to_python.py"   If  I change the script to   file1 = open("/home/user/udev.txt", "w") file1.write("Hello") file1.close()   then this script works.

Following are other questions which I think I need to know:   From a non X Session? (meaning root isn't logged into X) If multiple people were logged in on X, could I auto-detect who was on which screen, and thus programmatically detect which screen I need to launch the app on? Can I launch the app as the user? ( ok I'm 99.999% sure this is a yes ) Can I detect if users of group X are logged in to X?


$x_1 = \sin x_0 > 0$  $x_{n+1} = \sin x_n$   Prove   $\lim_{x \to \infty }$ $\sqrt{\frac{n}{3}} $ $x_n = 1$    having problem of trying to figure out what value for the $x_0$ starts at.

Consider the sequence defined as  $x_1 = 1$  $x_{n+1} = \sin x_n$  I think I was able to show that the sequence $\sqrt{n} x_{n}$ converges to $\sqrt{3}$ by a tedious elementary method which I wasn't too happy about.  (I think I did this by showing that $\sqrt{\frac{3}{n+1}} < x_{n} < \sqrt{\frac{3}{n}}$, don't remember exactly)  This looks like it should be a standard problem.   Does anyone know a simple (and preferably elementary) proof for the fact that the sequence $\sqrt{n}x_{n}$ converges to $\sqrt{3}$?


Say $G \cong H$ are isomorphic groups. Show $Aut(G) \cong Aut(H)$  I just made this up so I'm not sure if actually $Aut(G) \cong Aut(H)$ is true but I'm $99.9\%$ sure this should be true   I'm having trouble with the proof :'(  Let $\theta:G \rightarrow H$ be the isomorphism and $\phi\in Aut(G)$  Let $g_1,g_2\in G$ and let $h_1,h_2 \in H \ \ with \ \ h_1 = \theta(g_1) \ \ and \ \ h_2 = \theta(g_2)$  If $\phi(g_1) = g_2$  I want to show that $\exists \alpha\in Aut(H)$ such that  $\alpha(h_1) = h_2$  I tried composing $\theta$ and $\phi$ to get into $H$ but that doesn't get me anywhere. Is there something wrong with this approach?   Thanks ! :D  Wait a minute....  $\theta(\phi(g_1)) = \theta(g_2) = h_2$  $\theta(\phi(g_2)) = \theta(g_1) = h_1$  I think I see something here, $h_1$ and $h_2$ were permuted in the same way $g_1$ and $g_2$ were but $\theta \phi : G\rightarrow H$ so it cant be in $Aut(H)$

If a group $G$ is isomorphic to $H$, prove that ${\rm Aut}(G)$ is isomorphic to ${\rm Aut}(H)$.   Can someone provide a step by step solution? Explaining along the way our strategy in proving this.