Ubuntu 16.04: display manager fails to start

Question: Reposting the question from: https://unix.stackexchange.com/q/314129/193223
I recently upgraded from Ubuntu 14.04 to 16.04 after which the display manager stopped working.
Assuming it's due to the init systems, I tried to switch back to upstart by following the instructions given on this page:
https://wiki.ubuntu.com/SystemdForUpstartUsers
It didn't work.
<code>newton@gravity:~$ sudo systemctl status lightdm
● lightdm.service - Light Display Manager
   Loaded: loaded (/lib/systemd/system/lightdm.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/display-manager.service.d
           └─xdiagnose.conf
   Active: inactive (dead) (Result: exit-code) since Mon 2016-10-03 19:04:26 EDT; 13min ago
     Docs: man:lightdm(1)
  Process: 3533 ExecStart=/usr/sbin/lightdm (code=exited, status=1/FAILURE)
  Process: 3528 ExecStartPre=/bin/sh -c [ "$(basename $(cat /etc/X11/default-display-manager 2>/dev/null))" = "lightdm" ] (code=exited, status=0/SUCCESS)
 Main PID: 3533 (code=exited, status=1/FAILURE)

Oct 03 19:04:26 newton systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 03 19:04:26 newton systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 03 19:04:26 newton systemd[1]: Stopped Light Display Manager.
Oct 03 19:04:26 newton systemd[1]: lightdm.service: Start request repeated too quickly.
Oct 03 19:04:26 newton systemd[1]: Failed to start Light Display Manager.
Oct 03 19:09:02 newton systemd[1]: Stopped Light Display Manager.
</code>
journalctl shows issues with PAM kwallet.
<code>$ sudo journalctl -e -u lightdm
...
systemd[1]: Starting Light Display Manager...
systemd[1]: Started Light Display Manager.
lightdm[26952]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
lightdm[26952]: PAM adding faulty module: pam_kwallet.so
lightdm[26952]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
lightdm[26952]: PAM adding faulty module: pam_kwallet5.so
lightdm[26952]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
systemd[1]: lightdm.service: Unit entered failed state.
systemd[1]: lightdm.service: Triggering OnFailure= dependencies.
systemd[1]: lightdm.service: Failed with result 'exit-code'.

...
</code>
Here's the content of /var/log/lightdm/lightdm.log;
<code>[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.18.2, UID=0 PID=26937
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-log-backup.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.00s] DEBUG: Monitoring logind for seats
[+0.00s] DEBUG: New seat added from logind: seat0
[+0.00s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.00s] DEBUG: Seat seat0: Starting
[+0.00s] DEBUG: Seat seat0: Creating greeter session
[+0.00s] DEBUG: Seat seat0: Creating display server of type x
[+0.01s] DEBUG: Using VT 7
[+0.01s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.01s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.01s] DEBUG: DisplayServer x-0: Writing X server authority to /var/run/lightdm/root/:0
[+0.01s] DEBUG: DisplayServer x-0: Launching X Server
[+0.01s] DEBUG: Launching process 26944: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.01s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.01s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.01s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.01s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1007 added
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1009 added
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1006 added
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1005 added
[+0.01s] DEBUG: User /org/freedesktop/Accounts/User1002 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1011 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1008 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1003 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1001 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1004 added
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1010 added
[+0.23s] DEBUG: Got signal 10 from process 26944
[+0.23s] DEBUG: DisplayServer x-0: Got signal from X server :0
[+0.23s] DEBUG: DisplayServer x-0: Connecting to XServer :0
[+0.23s] DEBUG: Seat seat0: Display server ready, starting session authentication
[+0.23s] DEBUG: Session pid=26952: Started with service 'lightdm-greeter', username 'lightdm'
[+0.25s] DEBUG: Session pid=26952: Authentication complete with return value 0: Success
[+0.25s] DEBUG: Seat seat0: Session authenticated, running command
[+0.25s] DEBUG: Session pid=26952: Running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter
[+0.25s] DEBUG: Creating shared data directory /var/lib/lightdm-data/lightdm
[+0.25s] DEBUG: Session pid=26952: Logging to /var/log/lightdm/seat0-greeter.log
[+0.27s] DEBUG: Activating VT 7
[+0.27s] DEBUG: Activating login1 session c17
[+0.27s] DEBUG: Seat seat0 changes active session to c17
[+0.27s] DEBUG: Session c17 is already active
[+0.37s] DEBUG: Greeter closed communication channel
[+0.37s] DEBUG: Session pid=26952: Exited with return value 0
[+0.37s] DEBUG: Seat seat0: Session stopped
[+0.37s] DEBUG: Seat seat0: Stopping; failed to start a greeter
[+0.37s] DEBUG: Seat seat0: Stopping
[+0.37s] DEBUG: Seat seat0: Stopping display server
[+0.37s] DEBUG: Sending signal 15 to process 26944
[+0.50s] DEBUG: Process 26944 exited with return value 0
[+0.50s] DEBUG: DisplayServer x-0: X server stopped
[+0.50s] DEBUG: Releasing VT 7
[+0.50s] DEBUG: DisplayServer x-0: Removing X server authority /var/run/lightdm/root/:0
[+0.50s] DEBUG: Seat seat0: Display server stopped
[+0.50s] DEBUG: Seat seat0: Stopped
[+0.50s] DEBUG: Required seat has stopped
[+0.50s] DEBUG: Stopping display manager
[+0.50s] DEBUG: Display manager stopped
[+0.50s] DEBUG: Stopping daemon
[+0.50s] DEBUG: Exiting with return value 1

Any other debugging tips that I need to try?
</code>
Comment: Have a look at `/var/log/lightdm/lightdm.log` and `journalctl -u lightdm`.
Comment: Looking into those. I have also updated my question.
Comment: try some solutions here: https://askubuntu.com/questions/141606/how-to-fix-the-system-is-running-in-low-graphics-mode-error
Answer: It happened to me also try using gdm3 instead if you have it. If you have gdm3 then go to the terminal and type "sudo apt remove lightdm" and after that " sudo apt-get install lightdm".


part number of switching regulator component

Question: Can somebody help me to read this component part number?
i think its switching regulator.
thank you.
Answer: Looks like the 2A comes back to a MMBT3906 There are a few different variations and some of the manufacturers put a smaller letter on for date as well. MMBT3906-TP is one from MCC. Comes back as a transistor though and not a regulator.
Desc: TRANS PNP 40V 0.2A SOT23
Comment: thank you robert.but im looking for that 6 pin component
Comment: Sorry about that. Only option I came accross was if the part is updise down and the H8 marking could be IMH8A or UMH8N from Rohm. Not sure though they don't show the part markings on the data sheet.


how to restart asp.net application besides modifying web.config

Question: Is there a recommended way to bounce an asp.net application besides touching web.config from inside the application?  is HttpRuntime.UnloadAppDomain(); the preferred way to do this ? and if so where do you do this? In the unload of a page or some other place in the application?
Answer: Touching web.config from inside an application is a bad idea, IMO.  Also, the idea of having a file that you modify is a little hackney, IMO.
The documentation specifically states that UnloadAppDomain will shut the application down:

UnloadAppDomain allows programmatic shutdown of unused applications.

You should be able to make this call anywhere in the application.  Mind you, you might get a SecurityException, so make sure that the runtime gives you the appropriate permissions (you might want to put this in a library and make a call and then set the library up in the GAC with evidence to give it full trust).
Comment: yes. this is why I was asking. web.config modification seemed ugly and likely to get us written up on thedailyWTF.com :)
Comment: I think a better line to quote would be: "Terminates the current application. The application restarts the next time a request is received for it." The "unused" part in that quote could be read as "will only shut down if no one is using it", which is not the case.
Comment: Use System.Web.HttpRuntime.UnloadAppDomain()
Answer: If this is .NET 2.0 or greater, then you can add in an "App_offline.htm" file, make a request to the server, remove it, and then make another request to the server.
This sequence of events will force ASP.NET to unload the application for as long as the app_offline.htm file exists in the folder.
Scott Guthrie's blog entry on it:
http://weblogs.asp.net/scottgu/archive/2005/10/06/426755.aspx
Comment: @MikeJ - Also please note that this is NOT a programmatic change. You'll need to physically add and remove the file for it to work
Comment: doesnt htis just take the system offline. I want it to restart/reload with clean cache/session and the like. when I remove the app_offline.htm this will bring it back up by default?
Comment: @MikeJ - no. It shuts down the app and unloads the app domain from the server until the file is removed.
Answer: this code work for me. just call it to reload application.
System.Web.HttpRuntime.UnloadAppDomain();

Read more

This method will just unload our application. If you just put this method in an ASP.NET web button you are totally done. So when will our application reloaded? Actually if you click your button it will first launch our method and unload application. Further on the web page we are on at that moment will be reloaded as well, because we just clicked a button and the web page should refresh. After launching our method the page refresh process will cause our application to reload as well.
Comment: Seems to work well, and definitely the simplest solution given here!
Answer: You can stop and start the Application Pool associated with the app as well.
Comment: This would recycle every app using the same AppPool.
Comment: You can recycle the application pool using WMI: http://blogs.iis.net/chrisad/archive/2006/08/30/Recycling-Application-Pools-using-WMI-in-IIS-6.0.aspx
Comment: but this is from IIS right. in some cases I might not have access to the IIS box so I am looking for something programatic.
Answer: You can do this by calling the HttpRuntime.ShutdownAppDomain method (you will need to use reflection to invoke it, since it is a private static method)
See How to restart an IIS Worker Process programmatically (i.e. shutdown the current ASP.NET Domain) for an example of how I use this method in a 'Restart' REST API
Comment: Looks like this link is expired or broken.
Answer: You could safely restart a web application by creating or renaming a folder at run time under the application directory. Obviously you need to give the user assigned to run the application "modify" rights to the web directory or to a sub directory under it.
the method is mentioned at
http://www.bartlannoeye.be/blog/restarting-a-.net-web-application-without-restarting-iis
I used the following code to do it in my case. Modify it to work on a "writable" sub-directory
protected void RestartButton_Click(object sender, EventArgs e)
{
    //restart web app (instead of iisreset)
    DirectoryInfo dir = new DirectoryInfo(Server.MapPath("restart"));
    if (dir.Exists)
    {
        Directory.Move(dir.FullName, dir.FullName + "ed");
    }
    else
    {
        DirectoryInfo dired = new DirectoryInfo(Server.MapPath("restarted"));
        if (dired.Exists)
        {
            Directory.Move(dired.FullName, dir.FullName);
        }
        else
        {
            Directory.CreateDirectory(dir.FullName);
        }
    }
}

Comment: well this doesnt work for me. I see the directory being created but the application_Start event is not called upon!
Comment: That Bart Lannoeye link seems to be dead
Answer: If you don't want to stop and start the app pool you can always recycle it.


Netbeans Java Desktop Database application with login connecting to users from mysql

Question: I wanted to create a java desktop database application with the combination of the login window so that I will be able to display the user different types of options depending on their level assigned by mysql db. For example, some users may just have add rows privilege to specified tables and read on all others only. Is there any built in login swing window in netbeans?
Comment: Removed jdbc tag, because it is not related.
Answer: Not in the default JDK, but there are third party libs that have them.  I have used SwingLabs Login Form before and it has worked nicely for me.


If a WAF is compromised, can the adversary view all the traffic in clear text provided WAF uses SSL cert to decrypt it?

Question: I understand Web Application Layer Firewall (WAF) uses an SSL cert to decrypt and inspect the traffic before passing to the backend server. If an attacker could gain admin access to both the WAF application and the host server, is there any way they could view the sensitive information such as login credentials which would be present in the body of an HTTP request?
Comment: If attacker compromises the host, the WAF doesn't matter and needn't even exist; the host always has the plaintext. In practice web-host compromises seem to occur many thousands of times more than WAF compromises.
Answer: Yes, the configuration is as follows:
<code>[client web browser] <--TLS--> [WAF] <--TLS--> [origin web server]
</code>
So, the WAF essentially has a 'man in the middle' (MITM) position between the client web browser and the origin web server.  Therefore, the scenario that you describe is entirely possible.
Comment: The WAF must have the private key that corresponds with the public key in the certificate that it presents to the user's browser.  Otherwise, the WAF would not be able to inspect the plaintext requests from the browser, in order to do its job.  Hopefully, this private key is well protected (e.g. stored in a HSM).  But, notwithstanding, the WAF sees the plaintext, so if the WAF is compromised by an attacker, this attacker could see the plaintext as well.
Comment: @sxmad WAF systems generally have extensive logging facilities. Logs (in some cases including all of the information exchanged, sensitive parts logged indiscriminately) are generally guarded less than the private key. You just need to compromise the log storage.
Comment: Thank you. Are there any requirements for this to be possible? Someone suggested that a private key is required to decrypt. I'm worried that WAF might temporarily store the decrypted traffic in clear text for inspection during which an attacker could access them.
Comment: Thanks @mti2935 and fraxinus. This is helpful.


What would be most correct between 唇に持ち上げた and 唇まで持ち上げた?

Question: I'd like to translate a sentence starting as "He lifted the bottle to his lips...". I know both に and まで can be used to indicate destination. I think 彼はボトルを唇に持ち上げた may be better, because the lips are the final destination, however Google Translate gives preference to まで, and I'd like to confirm whether there is a reason for that.
Answer: 唇に is fine, but 口元に should be more natural (unless the lip is important in the context in some way or another).
唇まで (or 口元まで) is not wrong but it's not the first choice. It adds a nuance of "until it reaches the lip" or something like this. See: How to use へ (-e), に (-ni), まで (made) and の方 (no-hō) with destination and direction?


Mini ITX PSU and Power Brick Wattages

Question: So I have 4 systems with mini itx power supplies and am looking to purchase power bricks from the manufacturer. What confuses me is the power bricks are 102 Watts while the PSU can do 160W with a max of 200W. This is probably obvious question but since the power brick can only do 102 watts that means the PSU can only provide 102W, and if this is the case why would the manufacturer bundle the two together?
Answer: It's like the weakest point in the system.
For example on a car the tires may only be good up to 130 mph but the engine can go up to 140 mph. Or something like that, I'm not a car person.
Really it's being a bit cheap to only stock the 102W supply. If you want a decent 12V supply you should look at an ATX power supply. In fact the pico PSU could be replaced by one of these entirely. Only go for that brick if size is a problem. Even then, you can find a 150W ATX PSU in a small form factor nowadays anyway.
Additionally I would find it very difficult to believe that the pico PSU can provide 150W without cooking itself. Looking at it, the inductors are small surface mount types, probably not greater than 4-5 amps continuous. And I can't see a power transistor; if there is one, it would need some serious heatsinking. (Think about your computer power supply: 300-400W, about 2x as much as the pico PSU but with a large heatsink, plus it has a fan. Yes, one operates off 12V and one off mains, but the mains PSU's FET will actually have less current flowing through it and probably run cooler.) I would like to be wrong, but I can't see it.
Comment: I believe the trick with picoPSUs is that their input power is 12V so they only actually need to produce 5/3.3V power on the package and modern systems use very little of either.  The 160W model is rated for up to 8A continuous on those rails (in a case with good ventilation, less if fanless).  The big heat sinks you're expecting are in the 12V power brick which is much larger than a typical laptop model.
Answer: Apologies for reviving such an old post, but it's a question we see a lot.  The problem is running that much current at that voltage through such a small DC barrel connector.  Mini-Box has recently modified the power supply to include an inline P4 connector which can be removed and paired the 4-pin mini-DIN connector bundled with this 160w brick: http://www.mini-box.com/12v-16A-AC-DC-Power-Adapter

Mini ITX PSU and Power Brick Wattages


Flickering side-bars on Meta

Question: With the recent changes here, I've noticed something strange on the meta site.  Whenever I scroll, the side bars flicker.  It's a little distracting, and I was curious if others were having this problem, or if anyone had even noticed it yet.  This doesn't happen on the main site.
Comment: I was confused as to what you meant by sidebars; you mean the dark-gray background, right? Not the stuff with the related Questions and community bulletins and what not? I can reproduce this on Chrome Dev in Windows.
Comment: Also, I think it does happen on the main site, it's just not nearly as apparent.
Comment: Yeah, sorry.  I mean the gray background, which I guess only has visible flickering on the side.  Also, I see it happening in both Chrome and IE9.
Comment: Do you have smooth scrolling turned on?  Oh wait, never mind.  It's just not as noticeable (or seizure inducing) with it off compared to on.
Answer: This could be vsync issue.
Applying background-attachment:fixed to the body tag with the background should resolve this issue.
Comment: You're doing the Lord's work, sir. This fixes the bug. The change will be in the next prod build.

Flickering side-bars on Meta


How does CLTV prevent spender from spending the output?

Question: I have difficulty understanding how does CheckLockTimeVerify works. The BIP-65 which proposed CTLV says:

This BIP describes a new opcode (OP_CHECKLOCKTIMEVERIFY) for the
Bitcoin scripting system that allows a transaction output to be made
unspendable until some point in the future.

And the mechanism it works is by comparing the nLockTime field of the transaction by CLTV argument, if nLockTime field is greater than the CLTV argument the execution fails, otherwise will continue as if NOP had been executed.
I can't understand how it can prevent the spender from spedning the output before specific time or block height. Since the spender can simply set the transaction's nLockTime field to zero, then it's always spendable because zero is always less than or equal to nLockTime field. How does CLTV allow a transaction output to be made unspendable until some point in the future when the spender can create arbitrary transactions?
Answer:
if nLockTime field is greater than the CLTV argument the execution fails, otherwise will continue as if NOP had been executed.

This is backwards.
If the transaction's nLockTime is greater than or equal to the CLTV argument, then it continues as if a NOP was executed. Execution fails when it is less than the argument.
The code given in the BIP is confusing as it uses nLockTime to refer to the CLTV argument. The transaction's locktime is txTo.nLockTime.
Answer: The nLockTime transaction field allows you to specify the time before which the transaction cannot be part of the blockchain. You can define that time through the height of the block or in UNIX timestamp form.
The OP_CHECKLOCKTIMEVERIFY has the role of defining the time (block height/UNIX timestamp) before which the given output cannot be used. It works indirectly so that when the given output is referenced and the execution of the script starts, when encountering the given operator, the value given with OP_CHECKLOCKTIMEVERIFY and the value of the nLockTime field are compared. If the value of the nLockTime field is greater than or equal to the OP_CHECKLOCKTIMEVERIFY argument, the execution of the script continues, otherwise it is terminated and the transaction is marked as invalid.


AM-AM plot (input power vs output power) for power amplifier

Question: I have modelled a power amplifier using weiner's model in matlab.
But when I finally plotted the input vs output power plot I got a plot that grows linear , then reaches maxima and then starts falling. As far as I know it should saturate after certain input power. Could someone tell me the reason for such behaviour? The input signal I am using is 20MHz LTE signal.
Answer: I would assume that you are only monitoring the power in-band, and what is then occurring as the signal goes into saturation is that power is being translated to other frequencies due to the non-linearity. I would suspect that this would dominantly be power in harmonic frequency locations, notably the third and fifth harmonics.
Comment: How can I avoid that? I mean how can I make it get saturated?
Comment: Are you asking how you can maintain a constant output power in band as the input power keeps increasing? This can be done with a output power control loop; where you couple off some of the output power passed through a bandpass filter for your frequency band of interest, and then fed into a power detector which is the feedback for a leveling loop, controlling the gain in the transmit signal path. This if done properly will keep the amplifier from "clipping" your signal, which is causing the nonlinear distortion you are seeing.
Comment: But basically attenuating your input signal as much as you are increasing it such that the final power amplifier (if it is not the gain controlled component) is seeing a constant input signal above a certain input level, resulting in a constant output signal.


What is the origin of the phrase "cut the mustard"?

Question: What is the origin of the phrase "cut the mustard"?
Answer: http://www.phrases.org.uk/meanings/cut-the-mustard.html

There has been an association between
  the heat and piquancy of mustard and
  the zest and energy of people's
  behaviour. This dates back to at least
  1672, when the term 'as keen as
  mustard' is first recorded. 'Up to
  mustard' or just 'mustard' means up to
  standard in the same way as 'up to
  snuff'. 'Cutting' has also long been
  used to mean 'exhibiting', as in the
  phrase 'cutting a fine figure'. Unless
  some actual evidence is found for the
  other proposed explanations, the
  derivation of 'cutting the mustard' as
  an alternative way of saying
  'exhibiting one's high standards' is
  by far the most likely.
Whatever the coinage, the phrase
  itself emerged in the USA towards the
  end of the 19th century. The earliest
  example in print that I've found is
  from The Iowa State Reporter, August
  1897, in a piece about the rivalry
  between two Iowa towns:
Dubuque had the crowds, but Waterloo
  "Cut the Mustard"
The use of quotation marks and the
  lack of any explanation of the term in
  that citation imply that 'cut the
  mustard' was already known to Iowa
  readers and earlier printed examples
  may yet turn up.
Answer: Found this early use of the phrase in a letter from "Rusticus" in The Railroad Trainman, a journal of The Brotherhood of Railroad Trainmen, 1898. In the letter, he reminisces with another letter writer about his days as a trainman which he says started in 1872. He puts in quotes all the slang words and phrases he remembers from those days, of which cut the mustard is one. This may indicate a railroad origin to the phrase. Here's a quote from his letter:

I can cheerfully shake "paws" with him, in my mind, and bring to mind the time when box-toed shoes, squaretopped silk caps and black jeans suits with an inch of braid all around, and spring-bottom pants, were all the "go;" and you could tell a "car-hand" as far as you could see him with the naked eye. And the "pison" he could punish with the "captain" was a caution. Then a "gafter" could buy a job for $10.00, and if he could not "cut the mustard" he was liable to "hit the grit" between stations. Oh, those rosy-hued days, when a brakeman was an important feature about the depot platform about the time the "varnished cars" came in; and what a masher he was.

Edit 6/29/11:
Just found an earlier use of cut the mustard that again seems to indicate a railroad lingo origin. This (see story to rt. of burglary report) is from The Weekly Californian, of Kern County, California, December 3, 1892. It is an account of an anniversary ball put on by the International Association of Machinists. Its use here clearly indicates the "railroad boys" met or exceeded the expected standard of appearance:

The railroad boys were enthusiastic over their apparent success. Each had attended with his best girl looking her prettiest, in fact the boys themselves "cut the mustard" with the Bakersfieldians. The charming costumes of the ladies lent a brightness to the scene, which with the good music did not fail to elicit the appreciation of all present.
Answer: The first two quotations in the OED are both from the The Galveston Daily News (Texas, USA). First from 1891:

They applied several coats of carmine hue and cut the mustard over all their predecessors.

Second from 1892:

Time will reveal that he cannot 'cut the mustard'.

Their definition 3c shows the reasoning and some variants:

slang (orig. U.S.). Something which adds piquancy or zest; that which sets the standard or is the best of anything. to cut the mustard and variants: to come up to expectations, to meet requirements, to succeed. to be (to) the mustard : to be exactly what is required; to be very good or special.

And in the early 20th century are examples like "they were not the proper mustard" and "he's all to the mustard".
Answer: There may well be something in the railroad angle here, since wild mustard was regarded as a weed and a crop-destroying pest by farmers in the US — apparently railroad companies were obliged by law to remove it and other weeds from the embankments along the tracks, because it threatened to spread to the surrounding farmland.  The Mustard plant is also difficult to physically cut, being a hardy, tough plant...See this aricle from 1908 'Must fight the wild mustard'-
http://news.google.com/newspapers?nid=1314&dat=19080728&id=l65XAAAAIBAJ&sjid=n_MDAAAAIBAJ&pg=6650,131474
I guess someone who can't 'cut the mustard', is someone (a farmer or railroad company) that can't keep their affairs in order, or keep things neat and tidy, be 'up to scatch'... perhaps similar to the rural phrase 'gone to seed'?
Answer: http://www.etymonline.com/index.php?term=mustard

To cut the mustard (1907, usually in
  negative) is probably from slang
  mustard "genuine article, best thing"
  (1903) on notion of "that which
  enhances flavor."

http://www.unm.edu/~dave/words/mustard.html

O. Henry first used the words in this
  sense in his story "Heart of the West"
  (1907) when he wrote: " I looked
  around and found a proposition that
  exactly cut the mustard".
Answer: I always thought the phrase originated as "cut the muster". When the troops are mustered, only the best are chosen, and thus a person makes the muster cut.
Comment: I've heard before that "mustard" was a corruption of "muster", but never found a reliable source or citation for that idea, and the explanation doesn't make much sense anyway. One "passes" muster, one doesn't "cut" it.
Comment: In the pre-civil war US militia system, individuals who failed to appear fit for service were "cut" from the muster. In both British and US usage, units as a whole pass or fail muster.
Answer: In my Canadian experience there was definitely a sub-meaning for "cutting the mustard" that carried more of a sexual meaning. My grandparents made it clear that in their generation that this phrase referred to a man's stamina in the bedroom.
Comment: That's the same meaning, just another activity to apply the phrase to.
Answer: Cut the mustard probably relates to cutting the mustard plant, before it goes to seed, to protect the crops from being over-grown with mustard.  The earliest uses of the phrase all cropped up in rural areas - and the context in which the phrase was used is suggestive of the relationship with cutting the plant to prevent it from going to seed, as opposed to "cutting" the prepared mustard sauce for desired taste.
History and Etymology of "Cut the Mustard"

The idiom is known to have emerged in the United States in the late nineteenth century, but the underlying, original meaning of the phrase has not been fully understood.  Various explanations have been suggested, including the chore of cutting mustard plants, the difficulty of cutting mustard plants, diluting (cutting) prepared mustard condiments to achieve the proper flavor, or a derivation from the slang use of the word mustard to mean the thing that gives flavor.  Although each of the explanations, standing alone, sounds plausible, the evidence, or lack thereof, to support one meaning over another has just not "cut the mustard." ...
The idiom first appeared in Kansas in 1889, and most of the early examples of its use come from nearby Nebraska, Iowa and Missouri.  The location and timing of the development of the idiom, however, does not seem to have been mere happenstance; the seeds of the idiom, actual mustard seeds, had been inadvertently planted about fifteen years earlier, during recovery from the "grasshopper" plagues of 1874 and 1876.
Source: Early Sports and Pop Culture History Blog
Comment: You appear to be the author of the linked article. When linking to your own site or content (or content that you are affiliated with), you [must disclose your affiliation _in the answer_](/help/promotion) in order for it not to be considered spam. Having the same text in your username as the URL or mentioning it in your profile is not considered sufficient disclosure under Stack Exchange policy.
Answer: Just an idea:
     My dad used the phrase often and 'though I never knew its origin Dad always used it in the sense that one was not up to the task; couldn't be counted upon.  He sang a tune:
"He's gettin' too old,
He's gettin' too old,
He's too old to cut the mustard anymore."
    One "cuts" too strong liquids to make them useable or palatable, usually with water.  Mustard being quite hot may need cutting from time to time and if you're unable, you're not up to the challenge.
Comment: Nah. Per [JSBangs' answer](http://english.stackexchange.com/a/23765/2637), *cut* here is the older sense of *exhibit*, as in the phrase *cut a fine figure*. I don't believe for a moment the modern *dilute, adulterate* sense is relevant, since OED's first citation for this (chiefly American) usage is 1930.
Comment: @FumbleFingers what's more, diluting mustard is not a particularly challenging task.


Where is ttylinux's source code?

Question: I can not find ttylinux's source code anywhere. I tried googling with d/t keywords but no luck. So can anyone point me to a working link that i can download the source from, please?
Answer: According to whois, the domain ttylinux.net expired in October, and appears to be defunct:
Domain Name: TTYLINUX.NET
Registrar: DNC HOLDINGS, INC.
Sponsoring Registrar IANA ID: 291
Whois Server: whois.directnic.com
Referral URL: http://www.directnic.com
Name Server: EXPIRED-DOMAIN-NS50.DIRECTNIC.COM
Name Server: EXPIRED-DOMAIN-NS51.DIRECTNIC.COM
Status: clientTransferProhibited http://www.icann.org/epp#clientTransferProh>
Status: redemptionPeriod http://www.icann.org/epp#redemptionPeriod
Updated Date: 19-nov-2015
Creation Date: 08-oct-2008
Expiration Date: 08-oct-2015

See TTYLinux end is near and looking for maintainer(s) on LinuxToday.
Answer: The source code ISO that you can get via the Internet Archive is the collection of source code packages that were used to build ttylinux, with any patches. It will be hard to figure what you can do with that source code; there is no description of how to build it for ttylinux. Also, it probably does not have the init scripts that startup the ttylinux system.
Answer: Try the Internet Archive, e.g., searching for "ttylinux.net"
You can even grab e.g.,
ttylinux-pc_i686-2015.02-src.iso.gz from there.
Answer: Apparently, the code is now in https://github.com/JessiHash/crosslinux
I found a link to an archived page of ttylinux here: http://linux.wikia.com/wiki/Ttylinux As you can see there, it shows a git repository which no longer exists. However, the person that commited to the git repo is the same guy that according to a brief research was the original maintainer of ttylinux, Douglas Jerome.

Where is ttylinux's source code?


Double slit experiment done with magnetic fields?

Question: If we set up a double slit experiment, where at the slits we put a strong magnetic/electric field, and sent an electron through, what would happen? Would the magnetic/electric field collapse the wave function of the electron, or would the electron still create an interference pattern?
Comment: Why would the fields collapse the wave function? You would have to account for their effect on the electron propagation, sure, but that is all. You can certainly perform electron diffraction on magnetic materials for example.
Comment: The electrons already deal with a strong electric field ... when they pass close to the electrons of the atoms in the "wall" of the slit.
Comment: @DavidWhite Interesting comment because it takes in account that there is an interaction with the surface electrons at all. looking on the explanations for interference behind slits this point is not taken in account. I´ve published an answer to show how it is influenced. ANd if this is valid for electrons why it is not valid for photons? See http://physics.stackexchange.com/questions/158105/can-the-intensity-distribution-behind-edges-and-slits-be-explaint-by-the-interac
Comment: @HolgerFiedler, since photons obviously can interact with electrons, my opinion is that photons are influenced by their interaction with electrons.
Answer:
If we set up a double slit experiment, where at the slits we put a strong magnetic/electric field, and sent an electron through, what would happen?

Experiments with electrons on edges under the influence of an electric field were done in 1956 by G. Möllenstedt and H. Düker. ("Beobachtungen und Messungen an Biprisma-lnterferenzen mit Elektronenwellen" (Observations and measurements on biprism interferences with electron waves) from Zeitschrift für Naturforschung 10 a S. 256a). For deeper reading an excerpt of mine in poor English.

The two researchers from the Institute of Experimental and Applied Physics of the University of Tübingen directed an electron beam from a dot-shaped source through an electrostatic biprism. The biprism consisted of a gold coated quartz wire from two micrometers thickness (F), which was stretched between the two grounded plates of a plate capacitor.
If initially the biprism stays potential free, the entrance slit produces a shadow of the wire and outside the geometric shadow appear electron-free fringes, called according to the original script "FRESNEL diffraction fringes".

Applying a positive voltage of only a few volts on the filamentary center plate, the electrons of the two partial beams are bent towards the center. For the - in accordiance to light 105 times smaller cross section of the electron - a potential of +7 volts was enough for a successfully diffraction of electrons. "The wire potential was increased in small increments  from zero to + 7V. The small filament diameter from a few μ causes that the required for the beam deflection  field strength is achieved in the vicinity of the wire after just a few volts potential difference"(p. 384). With a positive potential the diffraction images of the right and left edges are shifted to each other.

Would the magnetic/electric field collapse the wave function of the electron, or would the electron still create an interference pattern?

As you see above, no. The intensity distribution behind slits (as well as behind any sharp or thin edges) stil appears. And the dimensions of the fringes are influenced by the applied electric potential.


Hot to get client context from external site?

Question: I have a sharepoint site (e.g. https://site1.sharepoint.com/). The Visual Studio generates code to get client context for current site. I need to get the client context from external site (e.g. https://site2.sharepoint.com/) by URL. I need to open login page for second site (probably using OAuth protocol), then create client context and use it with the first client context (to copy the data between them). How I can do that? Is it possible?
Answer: Provided that you're able to authenticate to the site, it is doable.
Here's an example of obtaining the client context.
<code>ClientContext context = new ClientContext("http://yoursite");
List list = context.Web.Lists.GetByTitle("Tasks");
context.Load(list);
context.ExecuteQuery();
</code>
Read more here: http://www.codeproject.com/Articles/399156/SharePoint-Client-Object-Model-Introduction
Comment: Thank you for your reply. But your code works only for current site. I can not find information about getting context from another site, that's why I asked the question here.
Comment: What errors are you getting?


Humans have tails?

Question: Today in biology class, my teacher said that all chordates have all the necessary traits, at least during the embryo stage, and we humans are chordates. So, one of these necessary traits was that they should have tails. My question is, humans don't seem to have tails, so how can they be chordates?
Comment: Oops.... I am always surprised when my vote to close alone is enough to actually close a question. I think @kmm answer is good (+1), I just wanted to highlight that the question can be though as a duplicate of another one.
Comment: What is meant by a "necessary trait"?
Comment: @MamaTank what I meant is that, a species can be called a chordate only if it has all the traits a chordate is supposed to have.
Answer: The chordate trait you are describing is more precisely termed post-anal tail. It is one of the basic characteristics of all chordates, along with, among others, pharyngeal pouches, a hollow dorsal nerve tube, and a notochord. Two other traits are less commonly considered chordate traits: segmented body musculature and a thyroid gland or endostyle (the latter particularly controversial).
These characteristics are present in all chordates at some point during their ontogeny. These traits are shown below.
We can see these most clearly in embryonic forms. For the post-anal tail: in humans, there is a short "tail" that extends past the anus (end of the yellow tube). This tail does not typically persist for very long. Similarly, the notochord is absorbed into the vertebral column, and remnants of the pharyngeal pouches are not externally visible.
The key phrase is "at some point during development." Non-embryonic humans don't have a tail, but that doesn't mean humans are not chordates.
Comment: What do you mean "non-embryonic humans"?

Humans have tails?


Ubuntu Screen Resolution

Question: How do I change the screen resolution in Ubuntu? I am dual booting Vista and Ubuntu. The preferences tab only has one resolution option for my computer.
Answer: You'll find xorg.conf in /etc/X11/
Edit it with any editor you have and like, but that won't fix the problem with the wrong driver.
You can try to go through this HowTo from Ubuntu to fix your problem. Hopefully it'll help.
https://help.ubuntu.com/community/BinaryDriverHowto/ATI
Answer: Then it probably didn't recognise your video card (did you install the proprietary drivers if you are using an NVidia or ATI card?) or your monitor. If you are using the right drivers already you will probably have to edit your xorg.conf manually and add the reolution you want.
Comment: It didn't. I have an Inspiron with an ATI Radeon and it isn't recognized. How do I edit the xorg.conf and what do I need to change? What directory is it in?

Ubuntu Screen Resolution


Video as splash screen on phonegap

Question: Video mp4 or any format as a splash screen on hybrid app like phone gap/cordova. like current Ubber App
Answer: I know i am quite late, But you can use the HTML5  tag to play a video after the document is loaded. Listen to event(video end) to hide the video and show the content that comes after the splash
Here is a sample

    <video width="100%" autoplay onended="splashEnd();">
        <source src="BT-logo-splash.mov" type="video/mp4">
        Your browser does not support the video tag.
    </video>

Within the function "splashEnd()" you can write what you want to do when the splash video ends
Also In my case the video is available locally within the app bundle. In case you are using a URL make sure to listen to other events for the  tag to make sure that the user does not has to face buffering at the beginning of app launch.
Answer: It is not possible to put mp4 or gif file as splash screen in phonegap/Cordova. You can load directly index.html page, There u can play video and you can navigato next page.
Hope it will help u.
Comment: hi naresh thanq for reply.. i try but video height and width not properly.plz share any sample one.....thanq
Answer: This is your splashscreen.html and splashscreen.js,include them in your app and redirect on home page after video playing is completed by setting setTimeout time

$(document).ready(function(){
         var url = $('iframe').attr('src');
         url = url+'?autoplay=1';
  $('iframe').attr('src', url);

        setTimeout(function(){
                //location.href="home.html";//redirect to home from here,you can set timeout to the video length
alert("video Completed");
            },5000);
        });

Answer: The cordova splashscreen is a native dialog which is shown while the hybrid application is being loaded in the webview. At least this should be the correct usage.
Any solution about showing HTML videos/animtions, etc. are about showing them in the webview. So it isn't usefull at all.
The best solution would be forking the cordova splash screen plugin and add videos supports.

Video as splash screen on phonegap


Number of ways in a Nim game such that First Player always wins

Question: Given $n$ piles of coins in a Nim game, how do I find the number of ways of making the first move under optimal play such that Player 1 always wins?
Answer: The complexity is $O(n)$ - you can compute the nim-value $p$ of the position as a whole, then nim-sum that with each of the column values $\{c_i: i\leq n\}$.  The valid (winning) first moves are exactly the ones for which $c_i\oplus p\lt c_i$.  (Note that you can't have $c_i\oplus p=c_i$ unless $p=0$, in which case there are no winning moves for the first player).  What's more, since just computing $p$ is $O(n)$ (you have to look at all the data), you can't really do any better than this.  (Though parallel algorithms are another story — I don't know what the complexity is in a PRAM model, for instance.)
Comment: Can you please provide a proof or reasoning for the condition $c_i\oplus p\lt c_i$? Is it because we are making the heap more balanced from an unbalanced position? Sorry, but I am new to Nim games.
Comment: @rayu after any move $c_i\mapsto c_i'$, the value of the new position is $p\oplus c_i\oplus c_i'$ (this is because we 'remove' $c_i$ from the position and replace it with $c_i'$).  This is zero (i.e., the initial move was a winning one) iff $p\oplus c_i\oplus c_i'=0$ iff $c_i' = p\oplus c_i$ (again, using that $x\oplus x=0$ for all $x$).  That $p\oplus c_i\lt c_i$ is then just the condition for the move to be legal - that is, to leave fewer coins in that pile than it started with.


Two polymorph any object cast in a row with same choice

Question: If two polymorph any object (PAO) spells are cast in a row with the same end result what happens? PAO is unlike all the other polymorph spells in that your type actually changes. So for the duration what type is used? Your current type from the first PAO spell or the type that you were before PAO was cast?
Comment: The goal is to use an intermediary step to up the duration to permanent, right?
Comment: Are you targeting yourself, a living creature, or an object? What are you polymorphing this thing into?
Comment: @JKimball that is correct, the goal is to increase the duration
Answer: The duration is based on the target's original state, not it currently transmuted state, as per spell's description:

The duration of the spell depends on how radical a change is made from the original state to its transmuted state.

Keep in mind that the target is not fundamentally a new creature/object, they are still the original target, but with a spell effect on them. So if dispel magic is cast on the target, the effect disapears, even if the duration of the transformation was permanent.
Your creature type is not changed by any of the polymorph spells. A spell that target's animals would not work on you if you are polymorphed into a bear, because your creature type is still humanoid. A rock polymorphed into a tree or dog still cannot be target of the Awaken spell.
Also, the polymorph subschool rules say that you cannot be under the effects of two polymorph at the same time. If that happens, you pick one to take effect:

You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.
Comment: I can't agree with the first argument in this answer. It's almost certainly *right*, but I can't agree with it. See, the term "original state" isn't actually defined anywhere in the rules; While you *can* reasonably interpret it as being a synonym for "true form" (or "the form it has when not influenced by magic"), you can *also* plausibly interpret it as "the state a thing is in prior to this specific casting of this spell." (I'm pretty sure you're right about which meaning the authors intended, but RAI arguments aren't accepted here.) I think your second argument stands alone, though.
Comment: You wont be under the effect of two at once, you will be under the effect of one which should influence the duration of the second. Im basically seeing it as a reduction of power requirements for the change.
Comment: @Fering I think the key is that you aren't going from original shape > shape 2 > shape 3, you are going original shape > shape 2, then original shape > shape 3. Each polymorph spell affects you individually and independently, as ShadowKras quoted.
Comment: GMJoe im going by what is said (similarly) on the transmutation school, where it uses "original form" a couple of times on a similar meaning.
Comment: Also, if one effect removes the previous one, and we would have to assume that the second spell would fail if your original state is no longer the same, because you couldnt be targeted by it otherwise. But i see your point, i will come up with more evidence for either.


Which scriptures portray Lord Ganesha to be the supreme God?

Question: I have seen many scriptures to portray Lord Vishnu, Lord Shiva, Lalita Devi and Lord Surya to be the supreme. However, I would like to know whether any scripture portrays Lord Ganesha to be the supreme. According to Adi Shankaracharya, Ganesha is the one of the 5 deities that can give liberation. Also there is a sect named Ganapatya which sees Lord Ganesh to be the supreme God. What is the basis for their claim? Apologies to anyone offended by my question including Lord Ganesha.
Comment: You don't need to apologize, especially to Ganesha.
Comment: @SwiftPushkar why don't you add an answer here also. It would be nice.
Comment: @AnuragSingh - yes thanks , I will try to give answer with mentioning of other scriptures also. :)
Comment: Here is the answer - https://hinduism.stackexchange.com/questions/7332/is-lord-ganesh-immortal
Answer: Many scriptures including Puranas portray Lord Ganesha as Supreme Brahman.
Here in Ganesh Purana - Chapter 10 - Vyasa's Questions - Lord Brahma tells Shee Ved Vyasa that Shree Ganesha is supreme Brahman.

There is a person who has neither beginning nor end, who is the source
  of the creator the universe, who contains the universe, who is the
  controller and sustainer of the universe, including those who exist
  and the non-existent, the manifest and the eternal. He can, at any
  time, create, destroy or change anything. The demigods, led by Indra,
  are always subject to his command, and have great faith in him. He
  removes obstacles for his devotees like Vishnu, Rudra, Surya, Agni,
  Varuna and the rest, but creates obstacles for others.
If you do not think of Ganesha before any pursuit, be it a spiritual
  or worldly concern, or even when entering and leaving your home, he
  creates an obstacle. Those who explain the meaning of the Sastras and
  the Vedas speak of him as supreme bliss, as the supreme path, and as the supreme Brahman. Child! Go, and respectfully take shelter of
  Dviradanana. If the illustrious Lord is kindly disposed, he will do
  whatever you wish. If not, you will not obtain your desire in a
  thousand years".

Gaṇapatistavaḥ which is said to be from Ganesh Purana -  upāsanā khaṇḍa adhyāya 13 also says following. The stotra to Gaṇapati is by Brahmā, Viṣṇu, Maheśvara as reported by brahmā.

अजं निर्विकल्पं निराकारमॆकं निरानन्दमानंदमद्वैतपूर्णम् ।
  परं निर्गुणं निर्विशेषं निरीहं परब्रह्मरूपं गणेशं भजेम् ॥1॥
Ajam nirvikalpam niraakaaramekam
  Niraanandam aanandam advaita poornam
  Param nirgunam nirvishesham nireeham
Para brahma roopam Ganesham bhajema
Brahmā Viṣṇu and Maheśa spoke: We should worship Gaṇeśa, Who is
  unborn, Who is free from change, Who is beyond taking forms (or
  actions), Who is unique, Who is without a support, Who is without a
  second, Who is bliss, Who is complete, Who is supreme, Who is beyond
  qualities, Who is absolute, Who is without passion, Who is supreme,
  and Who is Brahman. -

You can read full Stava -  Here

Also our famous Ganapati Atharvashirsha (Ganapati Upanishad)  says so.

त्वमेव प्रत्यक्षं तत्त्वमसि ।
  त्वमेव केवलं कर्ताऽसि ।
  त्वमेव केवलं धर्ताऽसि ।
  त्वमेव केवलं हर्ताऽसि ।
त्वमेव सर्वं खल्विदं ब्रह्मासि ।
  त्वं साक्षादात्माऽसि नित्यम् ॥2॥
Tvam-Eva Pratyakssam Tattvam-Asi |
  Tvam-Eva Kevalam Kartaa-[A]si |
  Tvam-Eva Kevalam Dhartaa-[A]si |
  Tvam-Eva Kevalam Hartaa-[A]si |
Tvam-Eva Sarvam Khalv[u]-Idam Brahma-Asi |
  Tvam Saakssaad-Aatmaa-[A]si Nityam ||2||
(O Ganapati) You indeed are the visible Tattvam (Conscious Essence
  underlying everything), (O Ganapati) You indeed are the only Creator
  (Karta) (by Whose Power the Universe is Created), (O Ganapati) You
  indeed are the only Sustainer (Dharta) (by Whose Power the Universe is
  Sustained), (O Ganapati) You indeed are the only Destroyer (Harta) (by
  Whose Power the Universe is finally Dissolved in its Conscious
  Essence),
  (O Ganapati) You indeed are All This (The Universe); You verily are the Brahman (giving Consciousness to All), (O Ganapati) You are the
  visible Atman, the Eternal (underlying Reality).
Answer: Their evidence is Ganesha Stava
Ajam Nirvikalpam
It translates to "Unborn"
There is another meaning behind Ajam, or Aja
It also means "Beam of the sun"

It basically wants to say that "Ganesha has the radiance of the sun."
We can find a similar meaning
"Vakratunda Mahakaya Suryakoti Samaprabha Nirvighnam Kurumedeva Sarva Karyeshu Sarvada"
The word in bold means "Who has the radiance of a million suns"
But people get confused.
Ganesha Stava
Ajam nirvikalpam niraakaaramekam
Niraanandam aanandam advaita poornam
Param nirgunam nirvishesham nireeham
Para brahma roopam Ganesham bhajema
People claim that Ganesha is supreme by the last line.
Para Brahama Roopam means form of Parabrahma, not Parabrahama.
There is a sect called Gāṇapatya, which worships Lord Ganesha as the supreme. For the people who follows this sect, will interpret this differently, but according to me, a Śaiva, this is my interpretation.
Answer: Chapter 13 of the Ganapati Khanda of Brahma Vaivarta Purana Depicts Ganapati as Brahman.

Lord Ganesha has All the universes Inside himself, states the Brahmandapurana.

प्रमथानां गणा ये च नानारूपा महाबलाः । तेषामीशस्त्वयं यस्माद्गणेशस्तेन
कीर्त्तितः ॥ २,४२.३३ ॥ भूतानि च भविष्याणि वर्त्तमानानि यानि च ।
ब्रह्माण्डान्यखिलान्येव यस्मिंल्लंबोदरः स तु ॥ २,४२.३४ ॥
There are groups of Pramathas who are very strong and who have various
forms and sizes. Since he is the lord of those groups, he is glorified
as Gaṇeśa. All the Universes (Brahmāṇḍas) of the past, present and
future are in him. Hence, he is called Lambodara.

~ Brahmanda Purana Section 3 - Upodghāta-pāda - Chapter 42


Is the extension of $*$ homomorphism unique?

Question: If $\phi:A\to B(H)$ is a $*$ homomorphism, do there exist two different $*$ homomorphisms $\phi_1,\phi_2:M(A)\to B(H)$ which extend $\phi$, where $M(A)$ is the multiplier algebra of $A$?
Comment: Interesting.  I think a counterexample might lie in the case $A=K(H)$ and $\phi:K(H)\to B(H)$ is the inclusion.  It is known that $M(K(H))$ is equal to $B(H)$, so to find a counterexample it would suffice to show that if $\phi:B(H)\to B(H)$ is a $*$-homomorphism which fixes $K(H)$, then $\phi$ must be the identity morphism.
Comment: @Aweygan: no such thing exists. Any completely positive map that fixes $K(H)$, fixes $B(H)$; that's (a particular case of) Arveson's Boundary Theorem. It can also be seen via Hamana's notion of *rigidity*.
Comment: @Martin Would you like to post this as an answer?
Comment: I have actually just posted an actual answer (which is a bit easier since we are dealing with representations and not just cp maps).
Answer: The extension is unique if $\phi$ is non-degenerate (i.e., if $\phi(A)H$ is dense). Proof below. If $\phi$ is degenerate, the extension is not unique. For instance let $A=c_0(\mathbb N)$, and $\phi:A\to B(\ell^2(\mathbb N))\oplus\mathbb C$, with $\phi(x)=(x,0)$. Here $M(A)=\ell^\infty(\mathbb N)$. Let $\phi_1:M(A)\to B(\ell^2(\mathbb N))\oplus\mathbb C$ be $\phi_1(x)=(x,0)$; for $\phi_2$, fix a free ultrafilter $\omega$, and let $\phi_2(x)=(x,\lim_{n\to\omega}x(n))$

The proof in the non-degenerate case:

If $J\subset A$ is an ideal, then any non-degenerate $*$-homomorphism $\pi:J\to B(H)$ extends uniquely to $A$. This answers the question in the negative, since $A$ is an (essential) ideal in $M(A)$.

Given $a\in A$, define $\tilde\pi(a)$ by (for $b\in J$, $h\in H$)
$$\tag1
\tilde\pi(a)\pi(b)h=\pi(ab)h.
$$
This is well-defined: if $\pi(b_1)h_1=\pi(b_2)h_2$, then taking an approximate unit $\{e_j\}$ for $J$,
$$
\pi(ab_1)h_1=\lim_j\pi(ae_jb_1)h_1=\lim_j\pi(ae_j)\pi(b_1)h_1
=\lim_j\pi(ae_j)\pi(b_2)h_2=\pi(ab_2)h_2.
$$
Also,
\begin{align}
\|\tilde\pi(a)\pi(b)h\|&=\|\pi(ab)h\|=\lim_j\|\pi(ae_j)\pi(b)h\|\leq\|a\|\,\|\pi(b)h\|.
\end{align}
This shows that $\tilde\pi(a)$ is bounded on $\pi(J)H$, and so we extend it uniquely to $\overline{\pi(J)H}$. With similar ideas, one proves that $\tilde\pi$ is a $*$-homomorphism.
For the uniqueness, assume that  $\rho:M(A)\to B(H)$ is a representation such that $\rho|_A=\pi|_A$. Then
$$
\rho(a)\pi(b)h=\rho(a)\rho(b)h=\rho(ab)h=\pi(ab)h=\tilde\pi(a)\pi(b)h.
$$
Thus $\rho(a)$ and $\tilde\pi(a)$ agree on a dense subset of $H$ and are thus equal.
Comment: Pro Argerami, I checked the proof,I can only conclude that $\rho(A)K^\perp\subset K^\perp$.How to deduce that $\rho(A)H\subset K$?
Comment: You are right. I realized that you have no uniqueness when the representation is degenerate. I have edited the answer.
Comment: No. You can have $\pi|_A=0$; in fact, you can have different such representations. For instance with $c_0$ as above, you can take two different representations of $\ell^\infty$ that are $0$ on $c_0$.
Comment: Sorry for hijacking a fairly old thread, I just have some question about the proof above.

Do we not require that $J$ be a closed ideal? Because otherwise it might be that $J$ is not a $C^*$-subalgebra of $A.$ Would the computation $\lim_{j}\|\pi(ae_j) \|\leq \|a \|$ still work even if $J$ is not closed? I don't think that $\pi$ will even be continuous if we do not force $J$ to be closed.
Comment: In the C $^*$ world, it is standard that "ideal" means "closed, two-sided". I wouldn't know how to (try to) prove this otherwise.


Are Fermi-Dirac-statistics relevant to view the universal system of neutrinos?

Question: Should the energy distribution of neutrinos be affected by Fermi-Dirac statistics? And if so, what would the consequences be? Could this locally cause weak interaction because of the Pauli Exclusion Principle?
Comment: NB: When you say "weak interaction", I assume you mean the pseudo-interaction (no forces are involved) in degenerate fermion matter. It is certainly not a weak interaction in the sense of exchanging virtual W and Z particles.
Comment: @RobJeffries. Weak interaction might not be the right term, but I mean beta decay etc.
Comment: But that is indeed a "weak interaction" and has nothing to do with the Pauli Exclusion Principle between identical neutrinos. Do you mean could the neutrinos be dense enough to prevent beta decay?
Comment: @RobJeffries. What I'm wondering is if there might be an explanation to the decay as caused by "neutrino crowding" among termic neutrinos - if there are such neutrinos in the neutrons?
Comment: "neutrino crowding" would *prevent* beta decay if the neutrino Fermi energy (in a degenerate neutrino gas) exceeds the maximum possible energy of the decay neutrino. At lower levels of degeneracy you would be reducing the available phase space for the decay neutrino so I presume the reaction would be somewhat inhibited.
Comment: No "pushing" then?
Comment: "Stimulated emission" does not happen for fermions. It is replaced by "inhibited emission"
Answer: Yes, neutrinos should obey Fermi-Dirac statistics and yes, the Pauli Exclusion Principle should operate for neutrinos.
But let's examine how dense the neutrino population has to be for this to be important.
The Fermi momentum is given by
$$ p_F = \left( \frac{3}{8\pi}\right) h n_{\nu}^{1/3} $$
where $n_{\nu}$ is the neutrino number density.
In order to be degenerate (and hence strongly affected by the PEP), then the following criterion can be used
$$ \frac{E_{F}}{kT} \gg 1,$$
where $E_{F}$ is the kinetic energy associated with particles with the Fermi momentum.
Neutrinos have very small rest masses and so would usually be considered relativistic, so we have
$$\frac{p_F c}{kT} \gg 1$$
which leads to
$$ n_{\nu} > \frac{8\pi}{3}\left(\frac{kT}{hc}\right)^3 = 2.8 \times 10^{6} T^3$$
in units of m$^{-3}$.
So, if this inequality is satisfied then neutrino degeneracy starts to become important.
Some examples:
The cosmic neutrino background has $T=1.95$ K, and a predicted number density of (for each neutrino species) of around $5.65 \times 10^{7}$ m$^{-3}$. Thus $E_{F}/kT = 1.4$. Not enough for the PEP to be super-important, but it is not completely negligible either. Actually, for finite neutrino masses it turns out that the neutrinos are probably non-relativistic at the present day resulting in the PEP being rather more important, because the neutrino temperature is lower than the 1.95K calculated for massless neutrinos. As a result there is a neutrino degeneracy pressure that may influence cosmic clustering of neutrinos (for instance see Pfenniger & Muccione 2006).
In the centre of a core-collapse supernova, the temperatures can reach $\sim 10^{11}$ K and the neutrino density could be as much as $10^{44}$ m$^{-3}$ per species. In this case $E_{F}/kT \sim 50-100$ and neutrino degeneracy is important. The resultant degeneracy pressure is an important component of the dynamics of supernovae explosions. It is partly neutrino degeneracy pressure that prevents the rest of the star collapsing onto the central proto-neutron star core.


Do I have 'health'?

Question: In Portal (and Portal 2), I can get hurt by lasers, bullets, etc. Do I have a finite amount of health that is depleted every time I get singed, or is it a case of sustaining damage for a continuous amount of time resulting in death?
Comment: I think its continuous damage = death
Comment: @fireDude67 I *think* that's what it is too, but I have no evidence.
Answer: You do have 100 health, only the exact number isn't shown on the HUD.
Continuous damage will kill you, but your health fully regenerates very quickly when you aren't damaged for a bit.
You can observe this in Portal 1 by giving yourself the HEV suit (console command give item_suit, needs sv_cheats to be enabled), which causes your health to be visible.

In Portal 2, issuing ent_dump player after being shot at by a turret displayed the following, so it's pretty safe to assume that it works the exact same way as in 1:
] ent_dump player
  [...]
  max_health: 100
  health: 10
  [...]

Comment: I've killed myself with lasers.
Comment: You can't even kill yourself with lasers.
Comment: @GnomeSlice I'm pretty sure Portal 2's lasers do kill you at some point, if you mash your face into them repeatedly. Maybe it's just the co-op bots, though.
Comment: I've definitely done it for minutes at a time with no exciting results.
Comment: @GnomeSlice Maybe this was changed in a patch and you tried it before that. Using `ent_dump`, I've verified that lasers do between 2 and 3 damage.
Comment: I've only played it on the PS3.
Comment: I too have killed myself with lasers, on the ps3.

Do I have 'health'?


Is the word "what" a pronoun in the question: Do you know what I mean?

Question: Is the word "what" a pronoun in the question: Do you know what I mean? I would be grateful for any suggestion.
Answer:
Do you know what I mean?

The "standard" classification for what in this context—a 'free' or 'fused' relative clause—is relative pronoun.
This classification ignores (or begs) a lot of very important questions such as

whether this what is the same word as interrogative what? in What do you mean?
whether this what is the same word as adjectival or determinative what in What song the Syrens sang or what name Achilles assumed when he hid himself among women, though puzzling questions, are not beyond all conjecture.
whether this what is in fact not a pronoun but a fused-head determiner
whether this what is properly classified as relative given that it can head only fused relative clauses and not (except in dialect use) the more central bound relative clauses

If you're really interested in any of these, throw up another question. But if all you care about is what answer to give on an exam, say "relative pronoun" and move onto something more useful.
Answer: I read this as indicating another phrase, I forget the exact term for this kind of sentence. It almost helps to put it in parentheses.
Do you know (what I mean)?
In that sense, what is the indicator that the phrase is dependent. That makes it seem like a preposition, but it is generally considered a pronoun, because sentences like "What does that mean?" make "what" the object of the sentence, like a noun.
Comment: Nope, it's a pronoun.  "The thing or things that...": "***What** I mean*" = "***The thing (or things) that** I mean*".
Comment: I'm sorry, You are correct. I should have looked it up.
Comment: Fix your answer.
Comment: @VictorBazarov Learn not to be rude.  Short imperatives can be quite distasteful.  (My use of a short imperative was intentional) :)
Comment: A smiley helps, don't it?


Armature Parenting Issue

Question: Dear Blender Community ,
    I am struggling to solve an issue concerning parenting an armature to another object (so I don't have to animate it separately. In this instance I'm trying to have my 'l' in slavery to be able to hold a pickaxe. The only problem is as the 'I' deforms back upwards to its resting position, the pickaxe stays stuck inside the rock. Do you guys have any ideas on how to fix it?
Answer: Not sure I understand everything going on, but if it's a problem with the whole armature, you could try parenting bone to your object. Then make that bone the parent bone.
Or you could try the child of constraint.

Armature Parenting Issue


Blender Cloud Login For 2.91

Question: I just bought Blender cloud, and I'm trying to find how to login. I saw that there is an addon but I was unable to find it. Is the Login Addon supposed to be included in blender cloud addon?
Answer: https://docs.blender.org/manual/en/latest/addons/system/blender_id.html
System: Blender ID authentication addon.
Search for ID in search and you will find it.
This is a doc loop that is unclear - a ticket should be put in place to mention that the addon referenced is an addon and not a website.
tickets can probably be put in to https://github.com/dfelinto/blender-cloud-addon
Answer: The Blender ID Authentication add-on is bundled with blender, and can be enabled from user preferences.

You login with the same Blender Id that you created when you joined Blender Cloud.
This is the same authentication that you use on cloud as well as the tracker.

Blender Cloud Login For 2.91


When is /var/lib/dpkg/status-old created?

Question: I've copied a dpkg-status file backup from /var/backups to /var/lib/dpkg/status, but I would like to restore the status file to what it was before the copy. Will status-old in /var/lib/dpkg/status contain a copy of the status file before it was overwritten?
Answer: Compare the date when you modified /var/lib/dpkg/status, to the modification date of /var/lib/dpkg/status-old, by running the command ls -lt /var/lib/dpkg/ | grep status-old this will show you when /var/lib/dpkg/status-old was modified last.
Just wanted to add this really nice answer in context to this question:Why you should not mess with /var/lib/ files.
Comment: it shows the same time as the status file. Does this mean the status file was backed-up to status-old before being overwritten? Or is status-old now the same as the status file?
Comment: Seems like it, don't you have the backup of the status file that worked in `/var/backups/`?
Comment: Thanks. Yes I saw some tips from that answer. I compared the backup with the true status file and there were differences. The status file and status old match after copying status-old to status. I am worried the differences were just recent packages I installed today meaning status-old was not a back-up. I will look more into it.
Comment: @rigger12 did you determine what the difference between `status` and `status-old` were?


swfobject detect swfurl status 404

Question: I have below code,
<code>var flashvars = {};
flashvars.src = "path-to-src";
flashvars.controlBarAutoHide = "false";
flashvars.poster = "path-to-thumbnail";
flashvars.autoPlay = "false";

var attributes = {};

var params = {};
params.wmode = "transparent";
params.allowfullscreen = "true";

var callbackfn = function(e){
//    console.log(e)
}

swfobject.embedSWF("http://fpdownload.adobe.com/strobe/FlashMediaPlayback.swf", "altContent", "800", "500", "10.2.0", "/path-to/expressInstall.swf", flashvars, params, attributes, callbackfn);
</code>
swfurl i.e.(http://fpdownload.adobe.com/strobe/FlashMediaPlayback.swf) in above code giving me 404 error hence video is not playing
Qn:

Is there a way if swfurl is 404 then we can replace it with other url (path-to-self-domain-swf)
I tried with checking broken URL as well but due to cross
domain policy it's not giving me desired result for swfurl status
Answer: SWFObject does not have any feature or ability for checking 404 status. In fact, it will report the embed successful, so long as the markup for the SWF was successfully added to the page. It does not validate that the SWF actually loads and plays.
SWFObject aside, cross-domain client-side 404 detection is not really possible. The most common suggestion is to use AJAX to try to load the file, but this fails when going cross-domain. If you check for errors when loading the file, you will not see specifics about the error (404 vs 403 or 500, etc). This approach is also expensive in terms of page load time and network requests -- you'd be trying to load the file twice.
What I'd do -- and this is a hack -- is try to load your SWF as usual but attach a timer that polls Flash Player to ensure the file is actually loading. If you don't see any progress on the load percentage over a given span of time, you can assume the SWF is not available and the load has failed.
For example (order of operations):

Load SWF
Wait one or two seconds
Poll SWF to check PercentLoaded value

If value is above 0, assume SWF is available.
If value is still set to "0", wait a little longer to see if it's just a network blip.

Poll SWF to check PercentLoaded value

If value is above 0, assume SWF is available.
If value is still set to "0", assume SWF is unavailable (we will not know why). Use your fallback.

A example for polling the PercentLoaded value of the SWF using SWFObject is available here: http://learnswfobject.com/advanced-topics/executing-javascript-when-the-swf-has-finished-loading/index.html
Comment: Thanks this seems to be practical solution, as of now I have added fallback swf. I will try above code and update you some time

swfobject detect swfurl status 404


Can I install Tridion 2013 SP1 with multiple Content Manager Servers

Question: I am looking for a document or solution to install and configure the Tridion 2013 SP1 with multiple Content Manager servers. It is kind of a pool of CM servers to service the requests.
Comment: Hi Prashanth and welcome to Tridion Stack Exchange. What parts are you not sure about? I'll post the documentation reference but add any additional questions or things you've tried to get better answers and feedback from the community.
Answer: The SDL Live Content documentation has scaling information under "Scaling SDL Tridion" (requires login).
Clustering the Content Manager isn't your only option. You could also look into scaling out the Database, Search, Workflow, or Publishing (as well as Content Delivery).
Edit:
Nick points out you cannot scale out the Content Manager Database. My mistake, I misread the following:

Installing database server on a dedicated machine  Except in a single-machine setup, always install the Content Manager database on a
  separate machine. Preferably, this should be a machine with at least 2
  GB of RAM that scales up easily, has multiple processors, and has
  network access in the Gigabit range. Set the default network protocol
  of the machine to TCP/IP (if you use SQL Server, use the Client
  Network Utility to do this).

So you can "scale" the database server up rather than out. Basically be careful with terms:

dedicated, as something on its own server
up or upscale, referring to threads or upgrading a server (RAM, CPU, etc)
out or outscale, the multiple servers you were looking for
Comment: Unless this changed since 2011sp1, you can't scale out the CM DB. It's not supported. The only thing supported is an active/passive configuration, meaning that the additional DB server acts as a backup in case the primary goes down.
Comment: Thank you very much Alvin. Yes, you are right, Clustering the Content Manager is not only the option. I was looking for the documentation to start with. For sure, I will be back with more number of queries.
Comment: You're right, Nick, on the dedicated DB. I updated the answer.
Answer: As Alvin says, you can scale out to multiple Content Manager servers (with a load balancer to manage the traffic to each).
As well as being able to spread the load and provide fault tolerance, scaling out the Content Manager and accessing the CME site through a load balancer allows you to easily put a 'holding page' in place (for the CME interface), if needed.
A holding page can be especially useful during deployments between environments, when you may not want editors to be editing or publishing content. (The administrators doing the deployment can have direct access to one of the Content Manager servers.)
If you do this, and scale out the Content Manager servers, then there are a few things that you will need to look out for:

You will need to ensure that the Content Manager Search is configured correctly - implementing a Master and a Slave setup.
As the Tridion Content Management Explorer interface is likely to be accessed on a number of URLs (the load balanced one and a direct one (for each server)), you will need to ensure that multiple host headers are configured properly.
You will probably need to implement 'sticky sessions' on the load balancer.
Comment: Thank you Williams for the valuable suggestions. I just started reading the details about scaling Tridion 2013 SP1 to manage the load and improve the performance of the overall system. I will be back with additional set of questions soon I start implementing it.


Can I get my Witcher Gear back?

Question: So I accidentally not knowing you can upgrade your Witcher Starting Gear dismantled it. Is there anyway of getting another chest? I know you can get better Witcher Gear, but I'm talking about the original Iconic gear.
Answer: You cannot recover the gear if you can't buy it back.
However...
You cannot currently upgrade the Witcher starting gear.
This was an odd rumour based on the fact that you upgrade the crafted Witcher gear, later on.
Examples: feline school armour, ursine school sword, etc.
Comment: Well, the starting armour has one upgrade actually (or at least it's used in a recipie) - but it's for level 4 I think, so it is rather unimportant in the grand scheme of things.
Comment: My apologies, I didn't manage to find that on my play through. Is it the serpentine school equivalent?
Comment: Nope, it wasn't green-quality, just one of the armours with generic sounding names needed it as a base instead of a shirt.
Comment: No, the armor you start with the Kaer Mohren armor you upgrade it to green witcher armor
Answer: To answer the question, no, it's gone for good if you dismantled it.
Comment: To be honest, you didn't answer the question, you answered a certain part of it.
Comment: Is there a way of getting you witcher gear back? no there isn't. Complete answer to the complete question. If you intened on asking more, you should have
Comment: "Is there anyway of getting another chest? I know you can get better Witcher Gear, but I'm talking about the original Iconic gear."

And there's the 2nd part of the question which you didn't answer. So I did ask more.
Comment: Exactly, there is one question there (Can i get the armor back?), followed by a statement specifying the armor you're talking about. What is the second question? The only implicit question is "if yes, how?" but since the answer is no, that doesn't apply.
Comment: How is "Is there anyway of getting another chest?" Not the 2nd part of the question, I can't see how that can be a statement.
Comment: That's the first part of the question

Can I get my Witcher Gear back?


Is it ok to fail with analysis?

Question: I'm a graduate student and I am really worried about the quality of my master thesis. It's my second year in graduate school and I've already done some pilot studies. But, entering the school, I was absolutely new in the real science (cognitive psychology) and now I'm afraid that data I collected is too dirty and statistical analysis I provided just incorrect. I have to present and publish my results anyway if I want to end graduate school and become a phd, but I feel ashamed of them.
So, I wonder is it ok to have problems with data when I'm just studying or I should refuse to publish or present these results?
My supervisor thinks everything's great and local journals will accept papers, but it is just bad, isn't it?
Comment: Mistakes are really, honestly the best way of learning. If your supervisor is happy, I think you are doing fine.
Comment: I cringe every time I have a look at my own old Ph.D. thesis. Your Ph.D. is the beginning of your academic/scientific career, and as such will contain your worst beginners' mistakes and your worst material all round. Rephrasing this in a positive way, you will improve as you gain more experience. As humans do. Anything else would be a surprise.
Comment: Cognitive psychology PhD here - the signals are weak, the noise is strong. But even then your effects may be replicable and tell a compelling story. Have faith in the data, for it is truth, but do feel free to note limitations and alternative explanations in your discussion.
Answer: Since your supervisor thinks that everything is fine, you should not be ashamed of publishing your results.
If you are still unsure: You should talk about your concerns to your supervisor and request an honest opinion. Keep in mind, that he/she is also (partly) responsible for the quality of your results!
Comment: If you explain the shortcomings of your data/analysis/methodology in your paper, then you can publish with a clear conscience.
Answer: Imposter syndrome

I am really worried about the quality of my master thesis

This is normal. You are still being educated in your field, but working alongside professionals, reading professional papers; this means you're judging yourself against an unduly high standard: of course your pilot studies are not "as good" as a "finished" piece of work from professor or a postdoc.
This can cause, and be compounded by, imposter syndrome. In imposter syndrome, you  fail to correctly judge the standard of your own work (or set your standards unduly high) and, as such, underestimate your own ability leading to the feeling of being an "imposter". This is incredibly common - most (non-sociopathic) academics will experience it at some point in their careers!
To overcome this (and to identify when perceived concerns are actually valid) it is important that you take on board feedback from your colleagues. Your peers (the master's and PhD students you directly work/collaborate with, attend class with etc.) and supervisors/lecturers will be able to help you identify your strengths and weaknesses. Most importantly, they will be able help you overcome the imposter syndrome by providing a realistic judgement of your skills. In your case, the feedback mechanisms are suggesting that everything's fine:

My supervisor thinks everything's great and local journals will accept papers

How to judge/assess your own work

I'm afraid that data I collected is too dirty and statistical analysis I provided just incorrect

The best way to deal with this situation, is as follows

Make a list of specific problems you perceive in your analysis (e.g. should have used this kind of hypothesis test, should have compared these variables).
Make any easy fixes (running a T test, for instance, can often be done quite easily).
Now consider whether the remaining "problems" seriously undermine your conclusions.

Do not use perfection as your standard for this: nothing in research is ever finished or complete, especially "pilot studies"; just consider whether the data supports your conclusions.
Consider if you can resolve any undermining by hedging or changing your conclusions (e.g. "x causes y" --> "x show strong positive correlation with y")

Look at published papers - is your analysis of comparable methods/standards? Have you performed a similar level of rigour?
Listen to your supervisor's advice. They're the expert. They've published before. If they think the paper's fine, it probably is.

When you follow this, you'll probably find that your work is in far better shape than you initially thought.

On a related note:

I have to present and publish my results anyway if I want to end graduate school and become a phd

Where does this come from? Unless publication is a requirement for graduation (unusual for a master's?), this simply isn't the case. You do not require publications to successfully apply for a PhD. So (unless they're a requirement for graduation) don't stress over publications, treat that possibility as a stretch-goal instead.

Some light relief
Comment: @Nij: if you click an image, you go to the source. I am not sure if that is enough reference, but still.
Comment: @Nij I'll happily replace the images with links for stylistic reasons (in response to a now-deleted comment), if desired. However, I'm bemused about claims of inadequate referencing. Hyperlinking of images is the default behaviour of the SE editor, and normal online practice, so it is surely expected and not "hidden". Additionally, the PhD comics images all clearly have "www.phdcomics.com" and "Jorge Cham (c) 2017", so I'm not sure how I could have referenced those more clearly?
Comment: References for the images would be appropriate.
Comment: Images are not usually linked, hidden references aren't useful references.
Comment: Images hyperlink to the host, not the source of the image, they are not always the same thing. It's not difficult to make the reference clearer: `[image] [via source](https://www.wherever-it-came-from.zzz)`.
Answer: I think the beautiful thing about a statistical analysis is that, when done right, it includes the odds that it is incorrect.
The honest thing to do is to include as part of your paper possible confounding factors that may make your conclusions invalid.  A good reader is thinking of these anyway, so it only makes you look better to state them in an open way.
You don't have to (and shouldn't) put this in a way that insults your work.  But perhaps something like, "A future study where [the data in question] is gathered in [suggested "less dirty" method] would be useful in further understanding this issue."
Frankly, I think your impulse to want a high quality standard for your work is an admirable one.
Answer: It is really difficult to answer this question without knowing your work (and knowing your field to some extent). Maybe there really is a problem with your work, maybe it is just impostor syndrome, which in my personal experience seems to be really common among young scientists. I don't think anyone here is in a position to tell you which one it is.
Personally, I believe that the reason scientists do low-quality work often is that they fail to recognize the problems with their methodology. Having doubts is normal, and I would even go as far as to argue that it might be a good sign because it shows that you have the right attitude, whether your doubts are justified or not.
I agree with the general sentiment of the other answers that it is probably best to ask for feedback from your peers. You have already convinced your supervisor, which is obviously quite important. If you need more positive reinforcement and are worried about particular problems in your work such as the statistical analysis part, consider asking someone to review just that part for you. I have often asked fellow graduate students who I believed to have more expertise than me in a specific field for their opinion on specific parts of my work. Of course, their opinion doesn't carry as much weight as the opinion of an experienced scientist, but it could provide you with some orientation. If several others think your work is fine upon closer inspection, I wouldn't worry about it.

Is it ok to fail with analysis?


node.js socket.io apache server

Question: I have some sort of noob question regarding to node.js and socket.io. These two guys are usually needed to use websockets for server to browser communication. Once that my project gets done, do I have to upload my php files to my apache server. Now my question is do I have also to upload my node_modules directory to my apache server? along with socket.io directory?
Answer: In order to run your node.js process you need to have ability to execute own applications on server. Classic virtual server does not allow of such functionality. There is virtual server hosting for node.js specifically, check out nodejitsu, heroku or any other.
You can run node.js as web platform by it self, without of use of any apache, that will make your life much easier. But if you still need apache and PHP, then you need to consider proxying from apache to your node.js process. This still can be tricky as proxying WebSockets is not straight forward.
If you have access to Apache settings, then you can enable proxying for HTTP/HTTPS, read this: http://ronenagranat.blogspot.co.uk/2011/02/apache2-reverse-proxy-for-nodejs.html
For WebSockets, there is not much data available but here is possible solution: http://blog.cafarelli.fr/post/2013/04/26/Backporting-Apache-support-for-websockets-reverse-proxy-(aka-getting-GateOne-to-work-behind-Apache)
Although if you have own server and have ability to choose between web platform, I would recommend to look into nginx, as it has support for WebSockets proxying (might require module and nginx recompiling).

node.js socket.io apache server


How can I recover Deleted files during Ubuntu setup, the drives are not there anymore

Question: I was using windows 7 32bit then it was showing some problems so I switched to Ubuntu and I accidentally deleted all my files on the hard disk during the Ubuntu setup....all those collection, pictures, videos and projects I had in my life is lost! Plzzz HELP ME!!!
Comment: Don't panic! You may get most (if not all) files back: http://askubuntu.com/questions/286181/how-do-i-recover-my-accidentally-lost-windows-partitions-after-installing-ubuntu
Answer: I am so sorry. If you wiped and reformatted your drive, there is no way practical way outside of a laboratory to bring that back.
If it's any consolation, it's happened to each and every one of us at least once.
Best idea is to be very careful when installing a new operating system, and/or to keep extensive backups. Use two hard drives - one for media and documents, one for your system software and applications - is also a good idea.
Comment: You don't need two hard drives, two partitions can do the same thing. The only caveat is that you need to know a little bit about manual partitioning.
Comment: Yes, they can, and no, you don't. I haven't (needed to) use multiple disks instead of multiple partitions in years. But if you're accidentally wiping all your files when you install a new OS, I'm guessing you'd benefit from a simpler solution - one that doesn't mean needing to know about manual partitioning ;-)


Pomelo.EntityFrameworkCore.MySql MySqlGeometry, EntityframeworkCore Migrations failed

Question: This is a simple case of use dotnet-ef migration tool to generate the MySQL database.
I have Pomelo.EntityFrameworkCore.MySql as the MySQL DB connector and class property:
public MySqlGeometry Location { get; set; }

The MySqlGeometry datatype supported by Mysql.Data.Types come with Pomelo package.
When I run
> dotnet ef migrations add InitialCreate

I get the following error:

No suitable constructor found for entity type 'MySqlGeometry'. The
  following constructors had parameters that could not be bound to
  properties of the entity type: cannot bind 'bytes' in
  'MySqlGeometry(byte[] bytes)'.

I guess the mysql geometry data type not supported by Pomelo connector? Or EntityframeworkCore Migrations tools doesn't support the MySQLGeometry data type? Or I miss any datatype package to support it.
Answer: While MySqlGeometry is supported by MySqlConnector (the underlying library used by Pomelo), it is not yet supported by Pomelo itself.
We have spatial data type support planned as a feature for the 3.1.0 release.


Sampling error example

Question: I've read the sampling error examples in Wikipedia, but I still don't understand. Could you give me a simple and characteristic example for sampling error?
Answer: Imagine that you want to know the average height of men on earth. This average height exists but obviously you will never be able to know it (unless you're able to measure several millions men...).
What you can do is measure hundreds or thousands of people and calculate the average height of these people. The average height among these people is probably not exactly equal to the average height of men on earth (because they are particular men in the whole population) but, if you did a good job (use a representative sample of the population), it should be close enough.
The difference between the quantity that you want to know (average height of men on earth) and its estimation through your sample (average height of men in the sample) is the sampling error.
Answer: When you take a sample you do so because you want to know what is happening in the wider population but unless you take a census and ask everyone there will always be a difference between the sample and the population.
There is a good definition below taken from here
A standard deviation is the spread of the scores around the average in a single sample. The standard error is the spread of the averages around the average of averages in a sampling distribution
A classic example is an opinion poll with a 95% confidence interval of + or - 3%
If the headline figure is 45% Democrats and 42% Republicans the reality amongst the real population is anything from 42-48% Democrats and 39-45% Republicans.
Another polling company could do the exact same survey and the results could be 44% and 43%. So which is right? They both are because a sample is only an approximation of the population and if you sample a population many times the results you get are going to vary a little bit.
The larger the sample the smaller the error. Hope that helps.
Comment: How about + or - 10% if the data is 15% Democrats and 12% Republicans (I'm concerned on figures only). I'm still quite confused if we add and deduct 10% of those numbers. Will they make sense? Thanks a lot!

Sampling error example


how to edit shader for all materials

Question: I have an object that has 100+ materials, and the roughness in each material is set to 1, is there an easy way to set it to 0.5 with a script or smth?
Comment: just an advice for the future: you should have given us more infos about your material because i posted now just the "easiest" case. If you have more complicated material - you should have written that in your question. But you can open as many questions as you want.
Answer: you can do it like this:
<code>import bpy

for eachSlot in bpy.data.objects["Cube"].material_slots:

    eachSlot.material.node_tree.nodes["Principled BSDF"].inputs[9].default_value = 0.5
</code>
But....
Prerequisites are:

all materials look like this:

you exchange "Cube" to the name of your object

Each slot must have an material which looks like 1)

how to edit shader for all materials


How to show consumer subsidy (rebate) on supply and demand diagram?

Question: I am currently working on an assignment and needed some help.
My assignment requires me to find an article relating to a form of government intervention such as taxes or subsidies and analyse the article using a supply and demand diagram.
For my essay, I have chosen an article that essentially talks about a rebate that should be removed. So far I have written that the consumer subsidy causes negative externalities and the removal of these rebates would help reallocate resources for incentivizing other methods. I know that rebates are essentially subsidies given to consumers to increase consumption, so they would affect the demand curve. However, I am stuck on the diagram as I am confused on which way the demand curve shifts and why. Would you please help me?
Thanks in Advance
Answer: Let $x = D(p)$ be the demand for a good if the price is equals to $p$. The inverse demand curve (as you would draw it) is then given by $p = D^{-1}(x)$. It gives the price as a function of the quantity.
If there is a rebate of $r$ and if $p$ is the price, then the consumer only pays $p^\ast = p - r$. Then the demand is given by:
$$
x = D(p^\ast) = D(p - r).
$$
Inverting this gives:
$$
p - r = D^{-1}(x),\\
 \to p = D^{-1}(x) + r
$$
So the inverse demand curve (as you would draw it) shifts up by an amount $r$.


Software to measure F-Score (formality) in English

Question: Francis Heylighen and Jean-Marc Dewaele defined a measure of language formality called "F-Measure" in a paper published in 1999 titled "Formality of Language: definition, measurement and behavioral determinants".  Is there software available that examines English text and determines an F-score, or some other objective measure of formality?
Comment: Note that text is not language, and "formality" is defined quite differently in speech. Also, in order to count nouns as opposed to verbs (for instance), one needs a parse of each sentence, so start with a tagging parser.
Comment: I'm not familiar with this measure, but be aware that there's something else called an f-score that's used in information retrieval and machine learning, and which is widely implemented in software.  I.e. searching will give you a lot of false positives.
Comment: Thanks for the feedback.  Maybe I should broaden the scope to software that provides more basic information like a histogram of parts-of-speech (e.g. nouns, verbs, pronouns, adjectives, adverbs, conjunctions, interjection, preposition).
Answer: I work with Heylighen & Dewaele's F-score as part of my research. If you need code, please let me know. Here are the three papers I wrote on this topic (another in progress):
paper 1
paper 2
paper 3