kworker is using almost 50% of processor
Kworker, what is it and why is it hogging so much CPU?
Extra slash added to the chat room URLs in the side bar Isomorphism between complex numbers minus zero and unit circle How do we show that $\mathbb{C}^{\times}$ and $S^{1}$ are isomorphic as groups? Why on earth are o-scopes earth referenced? Thinking about it: You would never find a "Grounded" multimeter as robust and useful if a path to ground through the multimeter were introduced, modifying the circuit's behaviour and possibly damaging the multimeter with currents.  Why are so many oscilloscopes earth referenced? Upon reading some educational material, a majority of the "common mistakes made by students" are placing the grounding clip incorrectly and causing poor results - when the o-scope is just being used as a fancy voltmeter!  I've heard of a Tek scope having an isolation transformer within.. however ignoring that, and taking in to account that newer DSOs may have plastic cases (isolated from you most importantly I would assume) could I just remove the earthing pin, and install a 1:1 AC transformer inbetween the o-scope and outlet and be on my merry way probing various hot/neutral/earthed sources with no worries about a path to ground any longer through it? I have an application running on node and using the mongodb library to establish connection and closing it. But the problem is, from the mongo serverStatus() command i can see that there is still 2k+ current connections still available.  &gt; db.serverStatus().connections { "current" : 2993, "available" : 835867, "totalCreated" : 220841 }   and most of it are having the active: false status.  My questions is, is there a way for me to force close these idle connections which after some time will affect my application with an timeout error.  I tried using the killOp() command but these only works if there is still opid value listed in these idle connections.  Appreciate some feedback on how can handle this kind of situations. Why do I have to specify runat="server" on all my ASP.NET controls when it is a mandatory attribute and server is the only option available in my limited knowledge of ASP.NET, and I get an error if I don't use it?  I do understand that I can optionally use it on my HTML tags, and I do understand the client/server paradigm and what it is actually specifying.  Is it a redundant tag that could just be implied by the control being an ASP.NET control, or is there an underlying reason? When is "self" required? I have been using classes for only a short while and when I write a method, I make all variables reference self, e.g. self.foo.  However, I'm looking through the wxPython in Action book and notice that "self" isn't used all the time. For example:   import wx  class TextFrame(wx.Frame):     def __init__(self):         wx.Frame.__init__(self, None, -1, 'Text Entry Example',             size=(300, 100))         panel = wx.Panel(self, -1)         basicLabel = wx.StaticText(panel, -1, "Basic Control:")         basicText = wx.TextCtrl(panel, -1, "I've entered some text!",             size=(175, -1))         basicText.SetInsertionPoint(0)         pwdLabel = wx.StaticText(panel, -1, "Password:")         pwdText = wx.TextCtrl(panel, -1, "password", size=(175, -1),             style=wx.TE_PASSWORD)         sizer = wx.FlexGridSizer(cols=2, hgap=6, vgap=6)         sizer.AddMany([basicLabel, basicText, pwdLabel, pwdText])         panel.SetSizer(sizer)   The one below does use "self".  import wx class ButtonFrame(wx.Frame):     def __init__(self):         wx.Frame.__init__(self, None, -1, 'Button Example',             size=(300, 100))         panel = wx.Panel(self, -1)         self.button = wx.Button(panel, -1, "Hello", pos=(50, 20))         self.Bind(wx.EVT_BUTTON, self.OnClick, self.button)         self.button.SetDefault()     def OnClick(self, event):         self.button.SetLabel("Clicked")   If I remember correctly, "self" is reference to a particular instance of the class, so when is it not necessary? Is there a general rule of thumb? Mount a VirtualBox drive image (vdi)? Is it possible to mount a VirtualBox drive image (.vdi) so the contents can be viewed in Nautilus etc.?  I have a windows 2000 .vdi which won't boot ("inaccessible boot device") after upgrading from VirtualBox 2.x to 3.1.6. I believe the IDE drive details have changed and that all I need to do is access the internal drive image and edit the Windows boot.ini to point to the new location. Was Red Shirt Security a rotating detail, like K.P, or was it a dedicated branch of Star Fleet like the M.P's are to the US Army? As I channel surfed the other day, I accidentally found an episode of Star Trek TOS, and I settled in to watch it. As always, it was a bad day to be a landing party Red Shirt Security person.    Their apparent lack of skill (training?) made me wonder: Was Red Shirt Security a rotating detail, like K.P. (Kitchen Patrol), that crew members with regular assigned duties were ordered to do when it was their turn, or was it a dedicated branch of Star Fleet like the M.P's (Military Police) are to the US Army? Naming threads and thread-pools of ExecutorService converting date string to date format "Failed to create user" due to regular expression error I'm running Ubuntu 12.10 desktop 32 bit. Currently I have only a user, type administrator. I'd like to create another administrator user but I keep getting the following error:  Failed to create user GDBus.Error:org.freedesktop.Accounts.Error.Failed: running '/usr/sbin/adduser' failed: /usr/sbin/adduser returned an error (1): adduser: Please enter a username matching the regular expression configured via the NAME_REGEX[_SYSTEM] configuration variable.  Use the `--force-badname' option to relax this check or reconfigure NAME_REGEX.  Any suggestion is appreciated. Animagi (Sirus specifically) and wands? I have 3 questions about animagus transformation and wands      Does animagus transformation require the use of a wand?   If yes, where does the wand go after the wizard transforms?   Again, if 1 is yes, how did Sirius transform into a dog in Azkaban?     Note that 2 and 3 are invalidated if the answer to 1 is no. If so, is it mentioned anywhere in the books, or can be implied by something in the books, that wand use is not required? I don't think Sirius managing to do it in Azkaban can be used as a proof here, as in Book 3 Wormtail needs a wand to change back into a rat Explode MULTILINESTRING into individual segments in PostGIS 1.5 I have a MULTILINESTRING in PostGIS consisting of several LINESTRING's. Consider each LINESTRING to have a set of POINT's      P1, P2, ... PN   forming the line segments     L1, L2, ... LN-1   where LX is the line segment connecting PX to PX+1.  Using PostGIS 1.5 how can I explode the MULTILINESTRING into individual line segments of each LINESTRING? Comparing two java.util.Dates to see if they are in the same day I'd like to know whether, given a system, there's a way to obtain all the conserved quantities. For instance if the system consists of electric and magnetic fields, the fields must satisfy Maxwell's equations. These equations are invariant under many transformations (Lorentz transformation, rotations, spatial and temporal translations, etc. By the way is there a way, maybe from group theory, to find all the possible transformations that leaves the equation(s) invariant?) which imply as many conserved quantities thanks to Noether's theorem. In wikipedia I can see an equation that seems to give all the conserved quantities () but it involves the Lagrangian and I'm not sure whether the formula is valid for all systems whose Lagrangian is possible to obtain. Limit problem arctg (1 ^ infinty) Can anyone help me with this limit problem without L'Hopital rule and Taylor series? $$\lim_{x\rightarrow\ -\infty}\left(-2\frac{\arctan(x)}{\pi}\right)^x$$ With ubuntu 19.10 I have been attempting to pair my Airpods with my laptop. There seems to be a problem with pairing and system is unable to add them as Bluetooth device. This happened after an upgrade from 19.04. Changing ControllerMode in /etc/bluetooth/main.conf seems to have no affect. Any help appreciated. A Jamaican committed marriage fraud about 30 years ago by marrying a US citizen in a marriage where the groom was paid a certain amount of money to marry her. The groom got in legal trouble for an unrelated matter, and the marriage fraud was discovered and the family friend was deported back to Jamaica. She no longer has any paperwork involved with the deportation and she can’t remember any of the details. I do not know if she simply agreed to return to Jamica when the fraud was discovered, or if she made any attempts to mount any type of legal defense in the case. I do know that she was cooperative with the immigration authorities and that they did not have to come looking for her. She would like to come the USA for a two-week visit. The main purpose of the visit is for her to visit a friend (US citizen) who is terminally ill.  I have been looking at 8 U.S.C. 1182 and from my reading of it, it would seem that she would not be admissible to the US because of the previous immigration fraud. My understanding is based on the section that says:     In general.-Any alien who, by fraud or willfully misrepresenting a material fact, seeks to procure (or has sought to procure or has procured) a visa, other documentation, or admission into the United States or other benefit provided under this Act is inadmissible.   What’s not clear to me is if this means that she would be inadmissible permanently or if this would be subject to the 10 year limit.  Can anyone help provide some clarity on this?  If the ban is not permanent are there any tips to being able to increase her chances of being able to get a visa.  She intends to honestly answer all questions during her application process for a visa. Do we still need swap partitions on desktops? I have read , but it was asked in the context of servers not desktops or notebooks.  If a good amount of RAM is installed on a notebook, say 8 GB, do we still need a swap space? Why does shell Command Substitution gobble up a trailing newline char?