What is the penalty for not complying with a quarantine order?

Question: According to the CDC, in most US states, breaking a quarantine order is a criminal misdemeanor.  If someone broke a quarantine order, what would be done?  Since the person is still contagious, would they still be incarcerated immediately?
Answer:
Since the person is still contagious, would they still be incarcerated immediately?

First of all, the law takes time to operate. While there is a constitutional right to a speedy trial, nobody is ever incarcerated as a judicial punishment or penalty "immediately". The police has a time-limited right to detain persons until they can be brought to court, and then the court system approves further detainment if necessary.
There are no real rules as to where and how detainment takes place, except that the conditions must be humane. In practice, if a patient who broke a quarantine order was a real menace, they would probably find themselves chained to a hospital bed in relatively short order. The trial would probably be postponed until the person sufficiently recovers from the illness that they can aid their legal defense. If the state won on the charges in trial, the person would then be incarcerated.
Prisoners get sick too, and it is common for them to be transferred to partnering hospitals that have special wards for patients in custody - which means additional perimeter security and typically chains on the hospital beds.
Comment: Think your second paragraph needs editing; if you commit contempt in face of the court, you can be in a cell five minutes later, and remain for weeks if the judge so orders.
Comment: @TimLymington The point is if you're harboring a super-pathogen that the CDC is trying to control you are *not* going to jail that day.


Counting long rests in music

Question: So, in orchestra we got given Bolero and the third trombone part has 236 rests before we come in (yes I counted). If you're wondering, I'm not some professional player, I'm the youngest in the group at 13 and the ages go up to around 18 (with a few exceptions) I've always counted by generally just listening to the changes in music, where from my experience, new set of rests are usually based on. I've tried using this strategy but it doesn't work well for this length. Anyone got any tips?
Comment: Possible duplicate of [How do you not get lost between measures?](https://music.stackexchange.com/questions/45868/how-do-you-not-get-lost-between-measures)
Comment: Also: https://music.stackexchange.com/questions/15591/how-do-you-count-many-bars-of-silence-rests?rq=1
Comment: Duplicate: [How do you count many bars of silence (rests)?](https://music.stackexchange.com/questions/15591/how-do-you-count-many-bars-of-silence-rests)
Comment: Being a violinist, I've never had to wait *that* long to play, but for me, listening to the piece over and over again is super helpful. Usually, I confess, I don't even have to count... Tricky with this piece in particular though.
Comment: See this answer: https://music.stackexchange.com/a/15660/9426
Answer: Listening for cue parts in specifically the Bolero is difficult, because of many repetitions and subtle changes, so I fully understand your difficulty, and I too get lost most of the times I listen to this piece. As others mentioned, I would expect the conductor to help your section with this problem, as he has the overview. But I can also offer some other tips:
1) Maybe understanding the structure of the piece would help you to be able to orientate yourself in the music. Maybe read this wikipedia article https://en.wikipedia.org/wiki/Boléro#Structure or other articles about the structure, and then listen to a recording of the piece and see if you can find cues you can use, especially in the instruments that are nearby to where you sit.
2) The very first theme on the flute starts after 2 bars, so if each round is 18 bars, then 236 minus 2 bars is 234 bars, which is exactly 13 rounds of the theme (of 18 bars).
3) Another great method I learned about counting many bars is to count the inside joints of your fingers with your thumb. Each finger (not including thumb) has 4 joints, so your four longest fingers times 4 joints makes 16 counts on one hand, which often coincides with the length of sections in some types of music.
Answer: Follow along with the music and maybe notate the score when a recognisable section comes up near to this part coming in, so you know when to count from.
A conductor should be making you aware of your part, but if they're not doing that then narrowing the time you need to count from to around 20-30 bars will certainly help. Maybe speak to your conductor (assuming you have one with an orchestra) and ask them to give you a cue to come in (or at least a cue to start paying attention)?
Answer: If you're a nerd:  I was second oboe in a university orchestra, so I also had to count lots of rests.  My brother taught me how to do it on my fingers: using binary counting, you can count from 0 to 1023 on your two hands.  Takes a little practice but it's fun.
https://en.wikipedia.org/wiki/Finger_binary
Answer: Conductors have a habit of stopping and restarting at some place in the middle of your 236 bars rest. One technique I use is to mark the absolute   bar number where you rejoin the fray.
So if the conductor says "start from bar 223" then you count 223 2 3 4 224 2 3 4 etc until you hit the bar where you start playing again.
Answer: Nobody would ever count 236 bars rest in that piece.
'Bolero' is probably one of the easiest pieces in the repertoire to navigate, no need to count anything. After the first four bars accompaniment there are always sixteen bars melody (with a very obvious ending) alternating with two bars accompaniment. All you need to do is note when the instruments near you are playing.
In the case of the third trombone part, all you need to do is listen to the melody and the other trombones. You can basically go to sleep until you hear the first trombone playing their solo at figure 10. Then comes a repeat of the 'B'-theme (figure 11), then twice the 'A'-theme (figure 12/13), then you're at figure 14 where both your trombone colleagues play (you can't miss that), and then you're at figure 15 where you play.
Answer: Yes, but your part doesn't have just one block of 236 bars rest, does it?

'Bolero' runs in very easily recognised sections, each featuring a different soloist.  They correspond to the rehearsal letters.
Admittedly, the illustrated part would benefit from a little more information.  Perhaps pencil in 'Trombone solo' at rehearsal mark 10.  (Then '1st trombone unclenches buttocks and sighs with relief at 11 :-) )  And it would be useful to know that Trombones 1 & 2 enter some time before you do.
Here's another, rather more helpful edition.  Sometimes the old edition doesn't NEED improving...
(Both examples from IMSLP)
Comment: It's especially nice when the part offers you a notated cue like this. Sometimes, if mine lacks it, I'll actually write one in (maybe not this long). This can also be especially helpful if you have to coordinate with an unusual or unpredictable rhythm. I also mark "milestone" events, like writing "cello entrance" over a certain measure.
Comment: I appreciate the notated cue in this part but I really dislike the unmeasured "Tacet until" rest; if I'm sight-reading a piece I'd really like to have a rough idea of how long until I come in.  In the best of both worlds you'd have *both* the counted-out rests and the trumpet cue.
Comment: @Michael Seifert    I'd generally agree with you.   But in this particular piece, with 14 well-defined sections to count and clear trumpet and trombones 1/2 cues, I think we can allow it!
Answer: When I was in the band we used to make a game out of counting long rests together as a section, looking back and forth at each other to check that we were at the same count as everybody else.
But seriously, I would say learn to be patient and count. There are good reasons to take it upon yourself to come in on time. It's good for your concentration skills to try to keep track of where you are in the music. It will also up your game and improve your musicianship to consider the rests part of the music and include silence as part of your performance.
Answer: I don't know how your sheet music is set up, but you should have some multi-measure rests between rehearsal markings. Instead of counting 200+ measures of rests in a row (if that's what you mean by 236 rests), you can count the number between rehearsal markings. For example, say you have 18 measures of rest between two rehearsal markings, I would count 1,2,3 2,2,3 3,2,3 4,2,3 and so forth up to 18,2,3. Then start over with the next multi-measure rest group. Another thing you can do is take a pencil and write a note to yourself what is happening at each rehearsal mark. This will help your ears to listen for and identify the musical cues and help you in the case you get lost with your counting.
Answer: As others have suggested, the best way is to learn the structure of the piece and learn how many measures you need to count from a given cue.
Alternatively (or additionally), you can also learn to count very large numbers on your fingers, for instance by using one of the methods described in this video:

Counting long rests in music


Terminology: complex of sheaves with cohomology sheaves concentrated in degree zero

Question: What is the proper terminology for a complex of sheaves $\mathcal F^\bullet$ whose homology sheaves $\mathcal H^i\mathcal F^\bullet$ vanish for $i\ne 0$?
Answer: In the context of t-structures, it's not unreasonable to call this just a "sheaf".  That is, in the natural t-structure on the derived category, the core is exactly the full subcategory of these things.  In the perverse t-structure it is, by definition, the category of perverse sheaves.  If one can say that a complex with vanishing positive and negative perverse cohomology is a "perverse sheaf" surely one can also say that a complex satisfying the vanishing of positive and negative cohomology is just a sheaf.
Answer: One can call it pure object.


Convert drum audio recordings to midi

Question: I recorded an acoustic drum kit with multiple microphones, and I'm not 100% happy with the sound. I have Superior Drummer 2.0, and I'd like to blend/replace my recorded drums with the samples. I understand that acoustic drum MIDI triggers would probably do the best job of this, but I'd like to avoid that expense if possible, and real cymbals are tough to make triggerable. Is there software that will convert the recorded drum tracks to MIDI signals? I'm thinking it could take some calibration for the velocities to register accurately, but something like this must exist, right?
Comment: Do a web search for "drum replacement software" or "drum replacement plugin". Most of them should let you convert to MIDI at the same time or instead of direct replacement.
Answer: You can do this with Logic Pro X or Ableton Live 9. Superior Drummer 2 should be able to plug-in to either one of them.
In Logic Pro X, you can place your acoustic drumkit audio recording on an audio track, and go Track ▶ Replace or Double Drum Track. Logic then creates a software instrument drum track with a MIDI representation of your acoustic drum track.
In Ableton Live 9, use the Session View, which is a grid where tracks go left-to-right and scenes go top-to-bottom. Create an audio track and a MIDI track, then choose a drumkit instrument for the MIDI track. Place your acoustic drums recording into the first scene on the audio track, and then drag and drop your acoustic drums audio recording onto the MIDI track. Because you are dragging the audio onto a MIDI track that has a drumkit instrument on it, Live will convert your audio into MIDI drums.
If you have multiple recordings for each microphone, then you just repeat the above for each recording until you have built out a set of tracks like kick, snare, toms, overheads, etc.
Comment: Just some follow up, I haven't actually tried out the solution yet (I use Logic Pro 9), but between Logic and Ableton, which software do you think handles this job better? I just realized that melodyne may be capable of this as well (which I own) so perhaps I'll try it out with that as well
Answer: I think you can easily bypass the midi procedure and actually try to fix the dynamics and stuff by using drumagog. This plugin has ,for a snare let's say, 50 samples, of the same snare hit with various ways and as it reads your signal it adapts in the best way it understands. In rock music where there are not a lot of dynamics and things are pretty standard it works wonders, lot's of new bands use it all the time in big records and stuff.
In addition you can put your own samples into drumagog or someone elses ! (slate etc.)  i think it's one step less towards your target!
The sound can also be mixed with the original signal so it feels even more humanized. There are 1-2 problems such as , if your overhead mics are not very close to the crashes and there's no isolation , you might find it hard to make the new snare cover the previous in the best way, and you'll have to fight it. But everything is manageable !  The same issue exists with the midi (concerning the OH).
Also you might run into some phase issues with your samples if you decide to mix them, also a thing you have to take care of.  But i think it's the best choice when you want to correct damaged drum sounds, with the less effort!
Comment: I must say, I really like this answer. I'm leaving the other answer as accepted since it directly answers the question about converting to MIDI, but I'm going to do some more reading on your alternative solution that may actually do a better job of fixing my problem.

Convert drum audio recordings to midi


Compiling SVN Perl bindings on Snow Leopard: tests fail

Question: At my work, we have to build our Subversion environment from source since it is deployed on shared applications servers and all dependencies must be contained within the user's home directory. I've developed a script that builds everything (including Apache 2.2.14, SVN 1.6.6, PHP 5.3.1, and MySQL 5.1.41) from source, and it all works flawlessly under 10.5 (Leopard) and 10.4 (Tiger). However, when I build it on 10.6 (Snow Leopard), everything succeeds except for the tests that ship with the SWIG Perl bindings for Subversion. Here's an excerpt from the first part of the epic fail, to conserve space:
<code>../../../../../subversion/bindings/swig/perl/native/t/0use.............ok
../../../../../subversion/bindings/swig/perl/native/t/1repos...........Directory needs to be empty but is not: Repository creation failed: Could not create top-level directory: '/var/folders/yD/yDpb4DctHjOFN0lC4QHjz++++TI/-Tmp-/svn-perl-test-l7N5wb' exists and is non-empty at ../../../../../subversion/bindings/swig/perl/native/t/1repos.t line 18
# cleanup
# Looks like your test died before it could output anything.
../../../../../subversion/bindings/swig/perl/native/t/1repos...........dubious
    Test returned status 255 (wstat 65280, 0xff00)
DIED. FAILED tests 1-6
    Failed 6/6 tests, 0.00% okay
</code>
(All failures have the same root cause, "Repository creation failed: Could not create top-level directory".)
I've tried everything obvious, and checked whether the directory it mentions actually exists before the test runs, and it doesn't. I'm puzzled why this works fine on everything but Snow Leopard. It even appears that the Perl bindings at least partially work, which makes the test failures all the more puzzling. I (and others I work with) would really like the assurance that the bindings actually work when building, so we can use pre/post-commit hooks that utilize the bindings and know they will work.
Solutions to what is causing these failures would be much appreciated. Thanks in advance!
Answer: Not a clue, but you are not the only person with issues with Perl and Snow Leopard: http://twitter.com/timbray/statuses/6156016213 https://stackoverflow.com/questions/1279939/how-do-i-fix-symbol-not-found-isprefix-when-compiling-perls-dbdmysql


Integrating a maven project into Eclipse

Question: I have a maven module for validation which I must pass to a old version of Eclipse which has the Jrules API within. However there is not a maven plugin for this eclipse IDE. So I figured I would do a maven:install on the module and move over the created jar.
However when I try to import->Existing Projects into Workspace->Select archive file:
and point it to the jar no projects appear. I'm at a loss as to how I can move my maven module to the outdated eclipse, without having to grab the 101 jars required for the project and non mavenise it...
Surely their has to be an easy way to this or is maven will monolithic
Answer: Use the maven-eclipse-plugin to generate the .project and .classpath files for you:
<code>mvn eclipse:eclipse
</code>
This will create the IDE metadata files which reference all of the JARs your project depends on from within your local maven repository folder.
Attempting to import the JAR that is built by the Maven build process into Eclipse using the " import->Existing Projects into Workspace->Select archive file" doesn't work because Eclipse expects to find a .zip/.jar file with the .project metadata files and the source code. Your compiled JAR likely contains neither.
Answer: I would recommend using the M2Eclipse maven plugin.  Right click the project -> Enable Dependency Management -> Update Project Configuration
I have used eclipse:eclipse extensively and my experience is that M2Eclipse is not only better supported but works better overall.
Comment: That of course depends on the "outdated" version of eclipse @Will has to use. I like m2e a lot more, as long as it works, but I'm not sure about how it works with older eclipse versions. I have used it with Indigo and Helios up to now.
Comment: @mliebelt good point.  I have use it with only newer versions of eclipse and it too has worked great


Is there any way to update

Question: I have bought Solid Explorer from the playstore. I've recently bought a LYF Flame 6, which doesn't support Google Play Services, but has playstore and works just as it is supposed to. But, still I if I download Solid Explorer, it shows that only the trial version is supported. I tried manually installing a pro apk, which doesn't give updates directly from the play store. I can't download the apk each and every time a new update is released. The app doesn't show in the list of "My apps". Is there anyway to force Playstore to show Solid Explorer in the list of my apps?
Answer: An app downloaded outside of the Play Store can't   be updated using Google Play update mechanism, it  won't appear in the downloaded list as well simply because not  your Google account that downloaded it.
An app downloaded from Google Play may not modify, replace or update its own APK binary code using any method other than Google Play's update mechanism.
The paid version isn't showing up may be because the developer has put restrictions regarding your country or your Android version, etc.
Update:
Try downloading your apps from a third party market such as Monogenie or Aptoide, you'll be notified whenever an update is available.
Comment: Well, I know those apps. But as an android dev, Playstore feels better for me, in terms of both UI and features. I had asked if there was any way to make playstore to give updates for apps which I've sideloaded with the apk.
Answer: There are also other 3rd party applications which have the ability to update installed applications, regardless from source. For instance I use an official HiApp to get updates for installed applications (even though I initially got them from Google play store).
XDA developers also made an APK updater which gets updates for installed applications. You may want to take a look here: apk updater. However I haven't checked if they do license verification or app purchases. If your goal is to get regular updates for your applications then it's worth a try.
Update sources:
At the moment three sources are supported:

APKMirror
APKPure
Google Play (Download from Evozi)
Comment: Ok, does it support updating paid apps? How many hours do those sources take to upload the new apk from the developer? I've got this error on "Google Play (Evozi). Please review the error from this screenshot: [link](https://we.tl/fgfGhPTQCO)
Comment: @sharath3589, thanks for the update, this site uses a secure https connections and other protocols (http) are not supported. Have you tried updating within the app?
Comment: I haven't downloaded the app yet. I was trying to visit the website as I'm not on my android though. I've seen that error for many sites in my chrome, how could I fix that?
Comment: @sharath3589, aww if you having this problem on most sites, its because they can longer accept unsecure connections (http), you can try to update your chrome browser or other alteratives which don't explicitly shw this error even if the website uses http protocol

Is there any way to update


Alternatives to 'shoe tree'

Question: Are there any cheap alternatives or homemade solutions to a shoe tree? I tried stuffing old newspaper into my formal shoes, but it creates a musty smell after a day or two.
Answer: Time for some CLAY.
Take some easy-mold clay, such as play-doh and put it inside a plastic cover, probably the cover of a sock. Stuff it into the shoe and press firmly. The clay should take the shape of the shoe, as if it were a foot within the shoe. After you are sure that the clay has taken up all the space in the shoe tip, pull it out carefully. Do not let the clay within the plastic cover change its shape. The Plastic cover will ensure that the clay wouldn't stick to the inside of the shoe. Now, we need the clay to retain the shape of the foot. For that you need to dry the clay, for which you could use so many methods such as sun drying or freezing it. Just ensure it doesn't become brittle and crumble-able. After it is dried, you could use it as a shoe tree. Optionally, you could remove the plastic cover, but be very careful if you decide to do so. You do not want your effort to be in vain by being too careless. You could use scented clay to give it a little fragrance too. That way you could avoid unwanted odor. You could add some fragrance to enhance the smell of the stored shoe also. Make sure it doesn't react with the clay mold.
Comment: This is a great alternative, I will try this. Also, will that dried clay longlast for several months together ? Do you have any idea ?
Comment: Depends on the quality of the clay. But I would advice you not to retain it for very long. This hack is pretty simple. So you could repeat the creation of this shoe tree once in a while to avoid the deterioration of the clay.
Answer: You can use plaster to cast a shape like the inside form of the shoe.

Mix plaster and water in a container like old plastic box (I use old bottles of water and cut the top)
Fill the mixture in a condom and tie it. You will have a "balloon" full of plaster
Clean the lubricant of the "balloon" under running water and gently wipe it dry with a towel
Now you can push the "balloon" inside the shoe
Keep it inside for several minutes and at one moment you will feel the plaster becoming hard
Take the hard plaster form out of the shoe and remove the condom
Leave it one day to become completely dry and paint it

Another way to hold you shoes full is to use a sponge for cleaning dishes. There is a large variety of sponges and you can choose s suitable size to put inside your shoes. And they are very cheep and you can change them often if you wish.

Alternatives to 'shoe tree'


Understanding CSRF attack prevention

Question: I've read multiple topics about web-specific attacks and preventions, but I'm still not sure if I got the point.
Let's imagine that we have a website (myapp.com) and a web service (myapi.com). The webapp and the service exchange data using JSON.
The service
The service has some restricted operations. To access any of these, the user has to log in using a username/password pair. (The passwords are hashed before they are stored in the database.) When a login request is valid, a random-generated token is sent back to the caller and its hashed version is stored in the database with the id of the logged in user. (The random token generation has to be strong so it cannot be guessed.) Each time a restricted operation needs to be accessed, a specific header must be set to the token above and it must be sent by the caller. This way the service can verify if a/which user is logged in (by hashing the token and searching for a database entity).
The website/webapp
When a valid login request is POSTed to the service, the received token is stored in the session. Each time the client (the browser) wants to access a restricted page, the app checks if the token is available or not (and redirects to the login page if the token is not found). Then it sends every request to the service with setting the required header to the token stored in the session.
The CSRF attack
There is an evil site (evil.com) that wants to (for example) modify the victim's password. There are 3 different communication line possible:
evil.com -> myapp.com
GET/POST: Both requests seem to be okay since the myapp.com requires a cookie with a session id to be able to read the token from the session. And because it is not provided by the evil.com, it will be redirected to the login page. (The evil.com can provide a session id but first, it has to manage to acquire someone else's id.)
evil.com -> myapi.com
GET/POST: Both requests seem to be okay since the web service requires a header containing a valid token. (Same as before, the evil.com can send a valid token in the header but first, it has to acquire one.)
evil.com -> victim
GET: Basically it seems to be okay. Even if the evil.com manages to create a GET request to the myapp.com through the victim, nothing will happen (besides that the victim will receive a HTML page)
POST: This is the real danger here (as far as I understand) because the evil.com can send a POST request through the victim's browser (e.g. by automatically submitting a form with hidden inputs) which sends the cookies (including session id) with the request, so the myapp.com sets the user's token to the header and finally, the service executes the action.
I've made a beautiful (just kidding) diagram about this:

How to prevent the CSRF attack
I'm planning to check the origin/referrer headers if they are present. If a request comes from a completely different site it can be rejected without checking anything else. But as far as I know, these headers are not always present. That's why we have to make some sort of verification. Or what is the downside of the origin check?
When the myapp.com generates the HTML view which contains a form, it also adds a hidden input with the value of the token stored in the session. This way when a POST request is received by the myapp.com it can verify that the hidden input is available or not and it can also compare its value to the value stored in the session. And since evil.com cannot read the victim's cookie, it cannot guess the required hidden field.
What about AJAX?
Is there anything else?
Since I'm just scratching the surface of the web security world, I'm not sure if there is anything else that can cause problems here. For example is there any additional header that can be useful to secure the application? What about older browsers that do not support some of the proposed solutions? It would be the best if you could provide me some examples (and preferably solutions or keywords) that can break through this defense.
As a side note: I'm interested (and have some experience) in php, Java (JSP, Servlet) and C# (ASP.NET). These might (and possibly) have different level of security built-in. I know that there are multiple trusted frameworks but my point is to learn about these things and not just have a "drop and it works" solution.
Related posts:

How to protect against login CSRF?
How does sending referrer HTTP headers protect against CSRF attacks?
Will "Authorization: Bearer" in request header fix CSRF attacks?
CSRF with JSON POST
Comment: The best way is to have a token that needs to be passed explicitly... unlike cookies which are passed implicitly.
Comment: tokens are backwards compatible. if you only care about useragents from the last 5 years, and deny all missing-header requests up-front, your token validation routine would never find a failure. Programming-wise, if a calculation is constant, it can be hard-coded instead.
Comment: why would the origin/referrer headers be missing?
Comment: @dandavis I'm not sure if it can be missing or not but according to [this](https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#Checking_the_Origin_Header) it is very rare. However if we can identify the request based on the origin/referrer, why do we need token-based checks?
Answer: As pointed before in comment, the OWASP website have a full list of protection methods to protect against CSRF attacks.
My preferred method is to do requests with AJAX (XHR/Fetch) that permit custom header and checking on the server side that the custom header exists, but it's opinion based.

Understanding CSRF attack prevention


Windows program to monitor a log file for new lines and automatically display them as they are added to the file

Question: I have text file, like log.txt which constantly updates.
I want some text editor which I can open on separate monitor to display this file.
I want this text editor to "reload" text file from disk periodically (every N seconds) and to scroll down.
What can you recommend?
Answer: If you prefer a GUI, you can use BareTail:

free and paid versions available
Windows
Portable
Like "tail -f" on Unix systems, but with many more features

Tail multiple files

Configurable highlighting

Optimised real-time viewing engine
View files of any size (> 2GB)
Scroll to any point in the whole file instantly
View files over a network
Configurable line wrapping
Configurable TAB expansion
Configurable font, including spacing and offset to maximise use of screen space
Comment: @СашаЧерных FastStone Capture (http://www.faststone.org/FSCaptureDetail.htm) can do the blurring effects on screenshots.
Comment: i like this tool, very handy
Comment: i tried all suggestions but this tool is the best, it's very fast and works fine even when log file grows fast
Comment: Franck, I'm sorry at offtop. What effect do you use on your first two screenshots? Thanks.
Comment: @СашаЧерных I got the screenshots from the web
Answer: If you just want to watch the log as it grows, look at the 'tail' utility in a command line window.
There's a port of some of the most common unix utilities to Windows at http://unxutils.sourceforge.net/
That package has the advantage that it requires nothing in the way of support - just drop the files somewhere in your path and they just work.
To use tail to watch a log file, open up a command line window (cmd.exe) and do:
tail -f <log.txt>

It'll just keep scrolling out the contents as the log file grows. Ctrl-C to stop.
Answer: You can use Windows PowerShell
(free, included in Windows XP and later):
Get-Content test.txt -Wait

To change width:

Useful info left by ADTC as a comment: you should also change the Defaults if you want the width to be saved and restored on a new PowerShell instance, see screenshot below.
Comment: You may want to mention that you should also change the **Defaults** if you want the width to be saved and restored on a new PowerShell instance. You can use [this screenshot link](http://i.stack.imgur.com/HvjRW.png).
Comment: i like it because it doesn't require additional software. default window width is 80, can I add some argument to change window width to 120 or 150?
Comment: @javapowered sure, added to answer.
Answer: If you have Git (or GitHub) installed, you can find the tail utility available in Git Shell*. You can use it to follow any file:
tail -f logfile.log

Those experienced with Unix and Linux terminals will find this very familiar. Try tail --help for more information.
* Usually this is a modified instance of Windows PowerShell.
You can also find the less utility installed with Git. As per the help text:
                         MOVING
F                    Forward forever; like "tail -f".

Note: I don't recommend installing Git just for this. But if you already have Git installed, there's no need to find third party tail or less utilities.
Answer: Log Expert is an open source alternative that is quite feature-rich. It has a so called tail mode to view the end of the file.
Some standard features:

colorization of rows based on regex patterns
search

Some original features:

columnizers - split a log row into fields and interpret fields as date, time, or various other  data types (you can write your own custom columnizer).
time sync - you can sync two files, and jumping to a certain time in one of them will sync the other to the same (or close) time

This Youtube video contains a screencast of the tool.
Answer: Or you can use less, a free and open-source tool written and maintained by Mark Nudelman.
less +F log.txt
The advantage of less is that you can toggle it between being a file viewer (this disables automatic scrolling, and lets you search and scroll manually) and a log follower.  Ctrl+C takes you into "less" mode (file viewer mode).  And Shift+F returns you to follow mode.
Comment: The question is tagged Windows. I don't think ``less`` would work there
Comment: @Timmy:  There are ways to install `less` on Windows.  If the asker needs help doing so, he can post a comment here and ask for advice.
Answer: During development I use Emacs text editor to monitor logs.
emacs-w32 from Cygwin is easier way to get Emacs and necessary environment.
Tail update to certain kinds of files can be added via:
(defun my/auto-revert-tail-mode-hook ()
  "Enable `auto-revert-tail-mode' for file in 'log' dir or ending on '.log'"
  (when (string-match "/logs?/\\|\\.\\(?:log\\|out\\)\\'"
                      (buffer-file-name (current-buffer)))
    (auto-revert-tail-mode 1)
    ))
(add-hook 'find-file-hook 'my/auto-revert-tail-mode-hook)

With TRAMP and ssh installed I can see updates in remote log files!
Answer: I wrote such a tool ("loxx") you can have a try at https://loxx.app/wp-content/uploads/loxx_setup.exe.
It supports filtering, color highlighting, regex search, time stamps and much more also for running logs (used Baretail for a long long time but missed some features).


Does learning 2 languages via different methods help reduce possible mix-ups?

Question: I've been learning Spanish for four years in school. Recently, I've started learning Italian via Duolingo. Does the fact that I use different methods of learning reduce the possible mixup of the languages?
Answer: Yes, learning via different methods helps reducing mix-ups. Take a look at this related question How can I avoid confusions when studying two similar languages?.
I am quoting Quill's answer here,

If you race cars, you might not have trouble driving normally, unless
  your brain can't differentiate the two similar environments.
I always found good ways to differentiate two similar things was to
  learn them in a different way:

Flash cards vs Memory match (Associating mental reflection of events    with terms)
Red cards vs Green Cards (Associating colours with words)
Study room vs Backyard (Associate locations and location-based stigma    with terms)

His answer essentially means that learning two languages by different methods will help us differnetiate each languages where mix-up occurs.
However if one the languages is your native lanuage then there are high chances that a mix-up occurs irrespective of the method you learn.
Answer: This isn't a neurological or biological answer, though I'd be interested to see one. This is my opinion, strictly speaking.
In my opinion, ultimately it won't make a difference. Or rather, as your knowledge of Italian and Spanish progress to a higher-advanced level, it won't make a difference.
On the other hand, it may reduce the cognitive conflict you experience as you are learning both languages. The way you learn both languages will be different and consequently the way you remember both, will be ever so slightly different.
As you gain practical experience and a degree of fluency, if you choose to pursue both languages to that extent, then the differences you had when learning them will vanish.
As a result of learning them in distinct ways, you might keep them separate for a while, but if you gain a comfortable fluency in each language, then it will eventually be altogether the same.


What is nuke it from orbit?

Question: I was reading this
Windows 2003 Enterprise infected by Conficker; post-infection problems continue
And they talk about nuking it from orbit (which apparently means wiping out the system and starting over) or at least doing an OS reinstall with full format
How are the two things different? Or is it because it is a server thing that these two mean different things?
Comment: "We must destroy the village in order to save it" = MilSpeak for The Viet Cong have so infiltrated everything that we can no longer differentiate between friendlies, civilian bystanders and enemy combatants. Which meant, "Call in the BUFFs for a complete carpet bombing to erase it." Same thing goes with a really complete virus/malware pwnage, burn it to the ground to kill the anthrax and start again.
Comment: Doesn't look like a duplicate to me. Both the questions and accepted answers are different. The duplicate question assumes you already know the answer to this one.
Answer: I say we take off and nuke the entire site from orbit. It's the only way to be sure.
Probably the origin of this saying.
In the context of having your computer infected by a virus: even if malware seems to be removed, it may not be - and the only way to be sure it's completely gone (and even then it's hard to be 100%) is to completely wipe the system and start fresh.
We all know what happens when you don't nuke Xenomorph's from orbit. Don't expect any better from malware.
Answer: The phrase nuke it from orbit basically means to wipe your system and start from a clean slate. What that clean slate might be differs in different situations.
If you perform regular backups of your system, which you should, restoring from a previous backup might be possible IF you were able to use forensics means to discover the time of infection. Restoring from a backup point before you got infected will be safe enough.
Of course, if you do not keep regular backups, you are in for a world of hurt. If you have important files on the system, you must diligently analysis each and every single file and ensure that it isn't infected before transferring it to the new, clean system. This is difficult.
Comment: so nuking is more robust removal method as opposed to restore points? How is it different from format and reinstall? Or does it also include reinstalling of the firmware for routers in case we are talking about servers and networks?
Comment: Yep. Less chance of residual infection from infected backups. You should be aware of malware that's persistent in things like the BIOS as well, in which case Nuke it might mean scrap the hardware as well!
Answer: "Nuke the site from orbit - it's the only way to be sure" is a quote from the movie Aliens, in which the protagonist suggests that an infestation of xenomorphs is so pervasive that a nuclear response is the only sure way to destroy it.
Synonyms in this context include:

"Flatten the box"
"Repave it"
"(FDISK,) Format and reinstall"
"Start again"

So when someone says "nuke it from orbit", they're really meaning "destroy it utterly". (and start over).
Answer: Substantial difference between nuking it from orbit and formatting disk is that malware may be also present on other components of your server than the disk.
As this answer to the linked question already states, malware can by now - at least theoretically - affect any flashable, persistent storage.
And since there are more and more components running a firmware inside one server, it would be really a PITA to verify each component's (flash) storage.
E.g. someone could modify your NIC's firmware, creating backdoor access to booting the machine from a remote source (network boot) or enabling/exploiting any other remote management feature.
Therefore: Nuke the whole machine!

What is nuke it from orbit?


Do I need to implement IPv6 support for my game?

Question: I'm going to implement network features for the game I'm currently working on, now I'm wondering if I need to implement IPv6 support or just having support for IPv4 is enough?
Answer: Your question, as specified, is far too broad to be answered. The answer depends on knowing what you're actually doing with networking.
For example, if all of your networking is done over HTTP and similar protocols, then IPv6 support is sufficiently simple that it's not really a problem. You could probably slap it together in half a day or so. In this case, there's really no reason not to.
However, if you're doing peer-to-peer networking over UDP, where you're trying to squeeze every bit into each packet, then IPv6 is not a minor thing. It has a larger packet header than IPv4, out of necessity. So that means less room per-packet for your data. That can mean that you need to employ greater compression or re-evaluate how much data you send or whatever.
I will say this: you should leave the option available. Look at the design of your networking system and make sure that you're not doing something that will, from an architecture perspective, make IPv6 implementation harder than it needs to be.
IP addresses should be within a type that could store an IPv6 address, for example. Your interface to the socket layer should be abstract enough that the basic act of sending packets (if your app does that) will be the same over IPv6 as over IPv4.
IPv6 is coming, and if you're going to actually release a game with networking, at least having a plan to support it is a good idea.
Answer: Short answer for this particlual case would be "No". Long answer would be "Is it likely to determine your game's success or failure"? At the time then IPv6 support will be a must you can update it quite easily, isn't it?
If it's just a matter of personal interest you can absolutely try to implement IPv6 support. But, for me, it's better to spend that time on actually making game better.
P.S. I'm almost sure that most big major game manufacturers already include IPv6 support for their games, but that's another story.


How to write a 12-bar blues melody

Question: I'm learning to write a 12-bar blues for a music theory class, and I'm a little confused about one point. I understand that the harmony is made of certain typical chord progressions (e.g. I-I-I-I, IV-IV-I-I, V-IV-I-I), but for the melody am I allowed to write anything as long as it's in the key of the song and fits well with each chord? Or am I supposed to ignore the chords being used and write whatever I want using the blues scale? Or a combination of the two?
Comment: Have you listened to any blues? If there's one style of music that you learn by listening to how other people play it instead of through theory, it's the blues. Also, pay attention to the lyrics, especially the use of repeated lines; they go hand in hand with how the melody works.
Answer: It's said that a good player playing without backing can make listeners aware of where they are in a sequence, and the 12 bar sequence is no different. The better fitting notes that work over the I don't especially work best over the IV or the V.
Often I hear players 'widdling' over 12 bar blues, using the notes from the blues scale at random. It sort of works, but there are bound to be clashes where other notes fit better. Targetting root notes is a good start, and an even better ploy is to use the notes from three blues scales - those of I, IV and V, in the appropriate bars. You'll find, after looking (and listening) carefully, that a lot of those theoretically 18 notes are actually shared between the three chords, which is one reason widdling on the I blues notes sort of works.
Add to those the major blues notes (as opposed to the more commonly used minor blues notes) and you have a lot in your armoury. Just think how each note fits each chord.
Answer: In typical melody writing the melody often uses tones that match the chords along with the careful use of non-chord tones.
But in 12-bar blues the general feeling is: any note of the blues scale can be played over any chord in the progression, so the rule of thumb above doesn't really apply to the blues.
Surely, the tonic and dominant tones will be natural resting points or central tones for the melody.
Focus on rhythm more than a traditional notion of melodic contour. Polyrhythm is very characteristic of blues, that means playing patterns of 3 melodically over a meter of 2 or 4. Syncopation is also characteristic, playing notes on the up beat.
Small segments of the blues scale often get repeated, like in C use C Bb G or Gb F Eb C. Often shorts riffs like this are play over all the chord changes without regard for the "clashing" notes. The clashing is fine with the general notion that you eventually get to some "resolution" on the tonic or dominant.
A sterotypes application of the above might look like...

...pretty corny, maybe too ragtime for what you want to do. But it does show cross rhythm, repeating riff, clashing notes over the F chord, and a syncopation.

EDIT
@Some_guy makes a good point about the "blues scale" in his answer. If you get fixated on a blues scale over chords you could get stuck into a rigid way of thinking. I sort the blues scale in my answer above. Let me offer this addition:
There is classic question of whether melody originates from scales or chords. The informed answer is both. But, this does open up the discussion to say: don't just look at the blues scale as a melodic resource. Also look at the harmonic palette.
I think the blues tonality can be described as an amalgamation of diatonic and characteristic chromaticism.
Let's cover the diatonic base first. Consider the three primary harmonies: tonic, dominant, and subdominant I V IV. We can overlap those chords...

V:   D  G B
I:  C E G  C
IV: C  F A C
All:CDEFGABC

...regardless of what anyone says about a blues scale the basic primary chords provide all the tones for a diatonic major scale. When minor sevenths are added to those chords to make the standard dominant seventh chords of 12 bar blues...

V7:   D   F G B
I7:  C E    G Bb C
IV7: C Eb F  A   C

...we get the additional chromatic tones ^b3 from IV  and ^b7 from I.
Further, let's add these characteristic blues embellishments of the dominant seventh chord...

...applied to the primary chords we get these sets of tones...

       A# C C#  E
V7:  G   B    D  F

       D# F F#  A
I7:  C   E    G  Bb

       G# Bb B  D
IV7: F   A    C  Eb

I reviewed my copy of West End Blues and it provides a special case I think is worth mentioning. Usually the blues scale is described as having a lowered mediant, a b^3. But West End Blues has the enharmonic equivalent of that tone, a raised supertonic #^2. But importantly, the occurrences of that tone are only over the dominant chord. In C the chord would appear like this...

...notice the D# instead of Eb and it resolves up to E natural.
As you can see the palette of tones in the blues isn't limited to a blues scale.
Going back to the concept of melody originating from both scales and chords we can create a melody of basic chord tones and their characteristic embellishments. You are not restricted to using only the blues scale.
Comment: If you look at the third bar of my embellishment examples you will see it as the _enharmonic equivalent_ `F#`. That difference in "spelling" is used to show the chord is an embellishment of the chord tone `G`.
Comment: The point in that example is to contrast the harmonic embellishment origin where the tone is a `#^4` scale degree versus the common blues scale which often is spelled with a flat 5 `b^5` degree.
Comment: As @Some_guy pointed out the blues scale over 12 bar blues dominant sevenths is sort of contrived, a quick and easy system. You will probably see both `#^4` and `b^5` in notation depending on harmonic context.
Comment: Where does the Gb come from in a C blues scale? It doesn't seem to come from the I-7, IV-7, or V-7 chords, so is it just a blue note?
Comment: @Nick The b3, the b5 and the b7 are blue notes. In C, the notes of Eb, and Gb (and to a certain extent the Bb too but that's more complex so let's ignore that for now) are specifically there *because* they clash with the CEG triad.  They are microtonally lowered notes that approach a consonance (the triad), but miss it, and they are used specifically for that characteristic "blue" (or clashing) sound.  Whether they are spelled as #2 or #4 is largely a matter of convenience of spelling in the musical context (#4 when leading to the 5, b5 when leading to the 4 usually.)
Comment: Michael Curtis pointed out that the blue 3 can also function harmonically as the 7 of the IV7 or as the +5 of a V+7 chord, and that's true, this function can be exploited, but it isn't the *derivation* of the blue notes. It _can_ serve these functions, but most of the time it's there as a sort of "weighed down major third". By contrast, there isn't this duality with the #4 / b5 ; it serves basically no conventional "harmonic" function, it exists purely as a blue notes. It's usually played microtonally too, and so would almost always be useless as, say, a major third to a V/V chord.
Comment: You can tell that the blue 3 isn't "from" the IV7 or V+7 by looking at how it's actually used: often over the 1 chord; it even features prominently throughout blues songs that **only** use the 1 chord, so there's no "harmonic" function to it all. That doesn't mean that it's not also used harmonically too of course: part of the appeal of 12 bar blues is that it allows that 3rd to be recontextualised. You often get AAB forms in the melody, where the second A is repeated over the new IV7 context (and usually the third is played closer to the 7 of IV the second time, microtonally speaking)
Comment: @Some_Guy one way the lowered `^3` is heard over the tonic chord is the 'high lonesome' bluegrass sound. That is clearly a lowered third over a major tonic chord.
Answer: The chords and the harmony are quite important for writing a blues melody:
Bars
1-2: write a motif starting from the root leaping up (minor 3rd, or 4th, 5th or dim. 5th descending the notes of the blues scale).
3-4: repeat the bars 1-2 with a minor 7th as final tone.
5-6: transpose the motif of bars 1-2 up a 4th or keep it on the same pitch by changing from major to minor: the minor third of the tonic (I) becomes the 7th of the IV
7-8: can be replaced by repeating the phrase of bars 1-2 or 3-4
9-10: the classical blues pattern V-IV using material of the opening motif or just any repeated and transposed 1 bar motif
11-12 can contain the elements of the original phrase ending to the dominant (V) for the loop.
This recipe will lead to some stereotypes but help to understand and analyse when listening to some standard blues. What you should do is listen, listen, listen.
Answer: There are many many different ways to write a blues melody, but none of them involve "applying the blues scale"
What you really need to do is listen to a bunch of blues, and learn how to play the melodies.  Then, use what you've learned to write the blues.
"The blues scale" has almost nothing to do with the blues though.  It's just a sort of facsimile invented to help people who don't really know what the blues is to sort of sound like they're playing the blues.
Your use of the word "allowed to" is pretty troubling as well.  That's not how writing music works, least of all writing blues music.
When writing a blues melody, you can use pretty much any note, expect I guess the flat 2nd/  And even then you could use that as a passing note.  And of course most blues melodies are microtonal, so they use "notes in between the notes", like the blue 3rd and blue 5th.
For a tip though, many blues melodies focus on the flat 3 for both the I and the IV chord because it works as both a blue third on the 1, and a flat 7 for the IV. Usually when you play the third in the blues, you flatten it more on the IV than the I. You might even hear singers sing a major 3rd on the 1 chord (or just a sliiiightly flat major third), and then flatten it all the way to a minor 3rd on the IV to fill out that IV7.  Then, on the V, you might move that 3 all the way down to a 2 (which is the 5 of the V)
Blues melodies sometimes "target" the chord more strongly, and sometimes "target" the home key more strongly.  Especially melodies on the 5 tend to hit some of the sweet spots for the 5.  But again, please please pleeeease don't try and write blues melodies by just "applying scales", listen to the blues, notice what notes are being used in melodies and solos, and try and learn from that.
The key fact is to hit the blue notes.  At its deepest level, blues is about that.  Spoonful by Howling Wolf has precisely 1 chord in the whole song, and the most prominent riff uses just 2 notes.  And it's great.

You're talking about 12 bar blues not a 1 chord vamp, but you can apply lessons from 1 to the other.
Answer: I'd say don't overthink it. If you listen to a lot of 12-bar blues, you'll find that there isn't really a lot of variation in the melody. That's because melody isn't really the point of the 12-bar blues. It's supposed to be formulaic, because it's the lowest common denominator in music. Because it's so simple, anyone can write it, anyone can sing it, and anyone can play it. Don't stray too far from the formula. Choosing a good turnaround is the best place to add some differentiation.
Comment: I don't think this answer could be any more wrong...  Melody is **everything** about the blues, that's the reason the chord structure is so simple. Blues is fundamentally a microtonal melodic music, like Indian Classical music for example. It's *all* in the melody, everything else is basically just decoration. That's why a lot of blues songs just use 2 or even 1 chord. http://youtu.be/9Ri7TcukAJ8 is just 1 chord the whole way through. Doesn't make it easy to play or write, because it's *all* in the melody.12 bar blues is just an extension of this, but with a bare minimum of harmonic movement.
Comment: I agree with @Some_Guy, melody will be key as the chords are the formula. This also reveals how important _rhythm_ is to crafting a good, unique melody. If some 12 bar blues music is formulaic, it's the _musician_ appealing to the lowest common denominator. In terms of harmonic formula, 12 bar blues is no more formulaic than a common 16 bar classical minuet. The quality of melody in either genre is a judgement upon the _composer_.

How to write a 12-bar blues melody


Can each Bitcoin and Satoshi be uniquely identified?

Question: I'm pretty sure I've read somewhere that BitCoins have an "address", so they can be uniquely identified.
What I want to know is:

Does each Satoshi have it's own unique identity?
How is the identity of a Satoshi formatted? (providing 1 is true)
Answer: Bitcoins and satoshis do not have unique identities.
However, Bitcoin balances are stored in uniquely identifiable "transaction outputs" that can only be spent by the owner of the recipient address.

Example:
   Alice sends Bob 1 BTC, Bob uses it to send another payment.
When Alice sends Bob a payment of 1 BTC, she signs a transaction that deducts 1 BTC from her funds and creates a new transaction output that is worth 1 BTC and can only be spent by Bob, the owner of the recipient address.
Bob now wants to send 0.4 BTC to Charles. The transaction output from Alice's transaction is now used to fund this new transaction. The transaction creates two new outputs: One with 0.4 BTC that is associated with Charles' address, and one with 0.6 BTC associated with Bob's address (it is the change). The first transaction output (from Alice's transaction) is consumed by the transaction.

Unspent Transaction Outputs are identified by the (unique) hash of the transaction they were created in, and their position in the list of outputs.
Answer: Can each Bitcoin and Satoshi be uniquely identified?
1. Does each Satoshi have it's own unique identity?
No.
If I show you transaction xyz on blockchain.info, you can see where the groups of satoshi's have gone (the transaction outputs) and you can see where the satoshi's have come from (the inputs) BUT you cannot identify which of the input satoshi's are given to each of the outputs.
You can also click on each input to find the transaction whose inputs were spent to create that output, and you can do this all the way back to the coin genesis every time but every time there is an input and an output all of the satoshi's are grouped so you cannot find an individual satoshi.
Answer: Each user of bitcoin need have at least one address to receive coins. I just created an address 18TGt8oGgLzkCpjxMbiRfvbDo9NqGisopp, which due to the properties of how it is generated, is presumed to be unique.
If someone sends me any bitcoin they will be taking a coin from an existing balance on THEIR account (another bitcoin address) which will need to be signed using their private key. Once the transaction has been broadcast to the network, it will eventually make it into a block which will allow you to then spend it by signing it over to someone else.
While balances are generally expressed to users in whole bitcoin units, or sub units such as bitmil, transactions are expressed in satoshis. For example, if you were to give me a 1 bitcoin tip for this awesome answer :P the transaction would be of 100000000 to 18TGt8oGgLzkCpjxMbiRfvbDo9NqGisopp.
For more information on transactions and how they work, you can check out this page on the bitcoin wiki: https://en.bitcoin.it/wiki/Transactions
Comment: I'm aware of wallet addresses, but I want to know if the coins themselves are uniquely identifiable. I'm assuming they must be identifiable in one way or another in order to prevent forgeries etc?
Comment: When you spend a coin you are spending a previous output (e.g. 100000000 to 18TGt8oGgLzkCpjxMbiRfvbDo9NqGisopp from 1anotherbitcoinaddress or from generate), which becomes the input for the current transaction. Each unique satoshi need not be identified but the input(s) needs be greater or equal to the output(s).
Answer: No, coins are digital divisible units even when it's noun refers to a physical indivisible unit.
There are nothing like I have 1/2 of this coin and 1/4 of that other indeed even the balance concept it self is ill defined in bitcoin due to multiple signature transanctions and other type of scripts.
Your balance is just the amount of Bitcoin that you can spend with the private keys you have.
On the other side as every transaction is traceable in the blockchain you can follow the trace of every generation transaction (the one that gives you the block reward) but there is nothing like a coin id.


Will it be a problem if there's a bit of overlapping date for I-20 and ESTA?

Question: I am currently in the US with an I-20 that will be expiring on 20th April 2016. I'm planning on going to Toronto for a short trip on 5th April and is planning to also apply ESTA(my country is under the visa-waiver program) for my re-entry to US. Will there be any problems if there's an overlap in date for my ESTA and I-20?
Comment: note that if you are entering by land, you don't even need an ESTA to enter on VWP
Answer: There is no problem with having an ESTA and another type of non-immigrant status in parallel. This is because the ESTA is only an electronic pre-authorization for travel and as such is not a visa.
However, note that you cannot perform studies towards a degree without entering the US on a suitable visa type. So entering under the visa waiver program after having had an I-20 may look a bit suspicious to the immigration officer. Thus, it makes sense to bring documentation with you that shows that your purpose of entering the US is compatible with the visa waiver program.
Related questions (although only considering J-1 visas) are:

Visa J-1 and Visa Waiver Program during grace period
I had a J1 trainee visa, can I go to Canada and come back with an ESTA?

Also see this link to an official US embassy site, which mentions a case where having an ESTA and a visa in parallel is actually needed in the answer to question 14, so having them in parallel should be possible. I got the link from a comment for this question.
Comment: I assume the "Documentation" you're referring to is, primarily, documentation that your studies have completed (or indication when they will resume if they're just paused), plus a ticket for returning home, plus if possible documentation of either enrollment at your home university if that's applicable, or a job, or something else?


Is it possible to avoid overstaying by entering airport earlier than flight?

Question: By some misfortune and bad luck I ended with Schengen visa of 8 stay days and the flight back is one day later. So, I shall have one day overstay.
Does it have any sense to show up in the airport one day early, so that I stay within stay day limits?
Comment: Can't hurt to try.  The hardest bit is going to be getting through security whenyour boarding pass has tomorrow's date on it.
Comment: I'm not talking about eyebrows.  Immigration is after the security checkpoint where you show your pass.  There may be a policy of not letting people in if their flight is too far in the future.  If you haven't already called the consulate that issued your visa, do that.  They may be able to extend its validity by one day.
Comment: It would probably help if you told us the airport you're leaving from (some are not even open overnight!), and what time your flight is.
Comment: @jcaron the poster's previous question indicates that he will be in Prague.
Comment: Yeah, it may cause some eyebrow rise :) Or maybe I could go to the embassy / consulate / police station and explain to them the situation?? Thanks for answer
Comment: Thanks once again, I will do that first thing tomorrow morning!
Comment: @jcaron - I shall be in Prague. One more issue also bothering me a lot is initial departure: is it possible that during first check, when I am arriving in Prague from Kiev, the border control does not let me in at all noticing that stay days are less than flight date by one day? :(
Answer: In order to avoid overstaying you'll have to clear border control exit checks before 23:59:59 on the last visa validity day. It might make sense to arrive (very) early in the airport in order to make the cutoff time. However the problem is that border control checkpoints are usually located after airport security checks. So the question really becomes: how early before my flight can I go through airport security checks?
The access to security checks is likely to be regulated by flight departure time. So is check-in, although you can always do that online and be alright if you don't have any hold-luggage to drop off. Keep in mind that you'll need a boarding pass to be allowed through security. I couldn't find any definite answer on the topic, and some forum posts seem to say that this is airport dependent. Personally I would call the airport and ask, not mentioning the overstaying issue but rather saying for example that you have an early departure and don't want to sleep in a hotel. I would also turn up at the airport and try my luck anyway.
As a final note make sure you make it through security checks at a reasonable time, i.e. one that is compatible with the opening hours of border controls. Indeed these might not be manned 24h, so you want to make sure that you arrive at the right time.
Comment: At VIE this early December, I checked in online, printed Boarding pass, no checked in Luggage, Security just warned me that your flight is after 9 hours, and if you pass here, you can not come back.


Why are anticausal systems even defined?

Question: I guess the same question is usually asked for complex numbers too, but the fact is that complex numbers are used all the time practically. However, at least on a quick google search, I couldn't find any applications of anticausal systems. So why define it in the first place?
Comment: I prefer the term "noncausal".  To a native speaker, "anticausal" implies a system whose response is only dependent on future inputs, where "noncausal" implies a system whose response is dependent on future and past inputs.
Comment: i might suggest the word *"acausal"* rather than *"noncausal"*.  Matt alludes to this point, but when doing non-realtime, offline processing (you are processing the sampled data of a signal stored in a file and outputing the resulting signal to another file), you can pretend the pointer to *"the present"* is wherever you want it to be if that makes your life simpler.  For linear-phase filters, you have symmetrey in the impulse response about a common delay, but you can make that a **zero-phase filter** by making that location of common delay equal to the *present time*, when $t=0$.
Comment: @TimWescott, I was indeed referring to a system where the response is dependent only on future inputs
Answer: Of course they don't exist. But we can stop time and use systems that would be non-causal if we hadn't stopped time. Stop time? Yes, just store your data and work offline / non-realtime. Or work on data that are not temporal but something else, for instance spatial. Of course, non-causal is a misnomer in that case, but the term is still used, in analogy with temporal signals and systems.
One common "non-causal" system that is used in offline mode is filtering followed by reversed filtering using IIR filters. This is done in order to eliminate phase distortions introduced by the conventional (causal/realtime) use of the filter. See this answer for the details.
Answer: First, because noncausal systems drop out of the math all the time, often when we're looking for some form of optimal filter.
Second, because if you don't mind adding delay to your system, or working offline, you can make a FIR noncausal system into a causal system simply by delaying it by the time span that it looks into the future.  For an IIR noncausal system, you can truncate the anticausal part of the response, and then delay the response so that your result is causal.
Answer: [EDIT: added a 2020 paper talking about retrocausal models in quantum mechanics]
I would not say anticausal systems don't exist, and I agree with wikipedia saying that "an anticausal system is a hypothetical system".
Because we don't know in time:  for traditional time-based signal processing, our human perception of time as a one-directional stream (the arrow of time) may be misleading. The fact that our brain and senses seem to perceive past only does not impede backward symmetry in physical laws. Some even model that antimatter could be matter moving backward in time (in some specific sense). Recently, the paper
Bell's theorem and locally mediated reformulations of quantum mechanics evokes that:

Specifically, some [...] parameters in these models must functionally
  depend on measurement settings in their future [...]. This option,
  often called retrocausal, has been repeatedly pointed out in the
  literature

Exotic theories can imagine that time might be two-dimensional. From a more pragmatic point of view, in simulation, one may consider to control a present state with future predicted values, which can be formalized by an anticausal system. Of course, in practice, those future estimations are obtained by past information.
Because we can extend this notion to other system variables (like space): Now for other non-time based systems: in $s(t)$, the variable $t$ is often called an ordinal variable. But we can have signals   $s(x)$ or images  $s(x,y)$ based on another variable, like space. Depending on the context, for other ordinal variables, there may or may not be a "unique direction" like for time. As long as you define one "forward" direction, the other can be considered "backward". This happen in image processing, especially in image filtering (which is a system). Some filters can be implemented very efficiently with a combination of a causal (left-right, top-bottom) and an anticausal one (right-left, bottom-top). Here, the causality direction is almost arbitrary, vaguely related to raster-scans. This is employed in recursive approximations to Gaussian, Exponential filters and thier derivative, like the Canny-Deriche or the Shen-Castan filters. See for instance in a DSP.StackExchange answer to: Which IIR filters approximate a Gaussian filter?: "Both filters are causal-anti-causal pairs".
So,  anticausal systems are defined not because one can exhibit one in reality (and not likely to be real-time), but because they are useful models, like instantaneous systems, or infinite precision computations, that are unlikely as well ("All models are wrong, but some are useful").
[About complex numbers] Even if they look odd (imaginary, impossible), they are very central, and some believe they are the most appropriate algebraic structure in many natural situations. Think again of the real numbers, do infinite sequences of decimals really exist?
Comment: I did say that complex numbers, although weird looking, are very useful in the question
Answer: The same theory that is used for temporal waveforms also applies to spatial waveforms eg in a camera picture.


"Il a les yeux noirs" ou "il a des yeux noirs"?

Question: In my french text book it has two sentence
"Il a les yeux noirs" and "Il a de grands yeux noirs"
I understand that in the second sentence, "de" is actually "des" but it changes because the adjective next to it. So why the first sentence use "les" instead of "des"
Comment: To add in a general way to the observations made below, you could consider the sentence with "les" as meaning something like "His eyes are black" and the sentence with "des" as meaning something like "He has big black eyes". As the others have indicates, the first presumes that you know he has eyes, while the second one is worded so as to introduce the fact (because it's "big eyes", which not everyone has).
Comment: Similarly, you could easily say "He has big eyes", but both "His big eyes are black" and "His black eyes are big" would represent a stylistically marked choice because the first adjective is slipped in without a corresponding "introduction" to the fact. "Il a les grands yeux noirs", where "les" makes a similar presumption as the English use of the possessive here, sounds about as odd as those two English sentences. The key issue is that both "les" and the possessive have *definiteness*: the quality of assuming that what you're referring to is already known to your interlocutors.
Comment: Normalement, c'est _Isabelle_ qui a les _yeux noirs_. Ah non, zut! Elle a les yeux _bleux_. J'ai tout confondu ;-)
Comment: It's the same as the difference between "His eyes are green" and "He has green eyes".
Answer: Both "Il a les yeux noirs" and "il a des yeux noirs" are possible but using les is more common.
Il a les xxx + mandatory adjective usually means this is something intrinsic, a characteristic of the person while il a des xxx + optional adjective just means this is something the person is currently having.

Il a les yeux noirs.

When talking about clothes, we would on the opposite more use des:

Il a des chaussures rouges.

You rightly wrote that in the second sentence, "de" is actually "des" but changed because of the adjective next to it but note that "elle a des grands yeux noirs" is nevertheless possible, and common in spoken French.
On the other hand, elle a les grands yeux noirs is almost impossible. That would mean the dubious "she has the large black eyes".
Answer: The key is the word "grands."  When talking about parts of the body, when the subject has them as one would expect (in this case, two eyes of a certain color), one uses the definite article.  With the phrase "Il a les yeux noirs," the subtext is that he has two eyes (like normal), and that they happen to be black.
Because grands is a subjective adjective - it changes the meaning slightly to show that his eyes are not as one might expect - they are big!  This subjectivity causes the indefinite article to be used.
For reference, this discussion and this thread may help.
Answer: Actually you can use "les" and "des" for the first sentence.
"Les" just sounds better because it refer directly to the eyes of the guy. But it can also make reference to some eyes that was previously refered in the story (the eyes was mentioned before and now he got it ... in his pocket)
"Des" would keep the doubt from where the eyes come from (not necessarly from the head of the guy you're talking about). Or it can be used to strongify the "noirs" (like it was "very black") but it's not the best way to express that of feeling
Those things I just explained there ... just forget it. Both work.
For a single situation 90% would say "les" and 9% would say "des" (1% can't say anything for multiple reason (e.g : blind people))
Answer: « Il a les yeux noirs » signifie que ses propres  yeux sont noirs . « Il a de grands yeux noirs » signifie qu'il a de grands yeux noirs comme ceux qui ont de grands yeux noirs.
Answer: "Il a les yeux noirs" could be an answer to "how are his eyes ? ", more a precision on a single part,
"il a des yeux noirs" could be an answer to "how is this man ?", more a descriptive feature.


Pre-define a check list in Trello

Question: In Trello, can you pre-define a check list automatically?
We could use this to check off Product order and provision stages.
Answer: You can create a card with the list you want, and then use this card as a template, by copying the card to the list you want.
For things like this, I actually have a list with is just templates of cards I use whenever I need.
Answer: Trello just recently (last week) implemented the Checklist Copy feature: when you add a new checklist, you can now "Copy Items From…" an existing card's checklist.

Pre-define a check list in Trello


Learning Russian from completely beginner to B2/C1

Question: I have 1 year to learn Russian from completely scratch to at least B2 level in TORFL. I will go to an intensive language course in St. Petersburg, Russia. The course will be 20 hours per week, I assume. How likely to achieve such a goal? My entire work will be this in Russia. Also, my native language is Turkish and I am B2/C1 level in English.
Comment: By the way, this question reminded me of a similar one about the [feasibility of reaching B1 in German in three months](https://languagelearning.stackexchange.com/q/2866/800).
Comment: This is not answerable. We cannot tell you how much success you will have, because we do not know how much time beyond 20 hours per week you will dedicate to the study. If you spend all your waking hours studying, it is certainly doable. But before you start with Russian, you can try self-study Esperanto. Search this forum if/how/why Esperanto improves chances to learn other indo-european languages.
Comment: Just to make sure that I don't misunderstand the question: you want to know whether it is possible to reach level B2 in one year, starting from scratch, by living in Russia and attending a language course there for 12 months? (20 hours per week * 52 weeks = 1040 hours of classroom hours (ignoring holidays etc.))
Comment: Thanks for your attention and help, @PeterMasiar. I will be there for one year and my only occupation and goal will be learning Russian, my classes probably will be 4 hours per day and 5 days of week. So, I can and must dedicate my out-of-class hours. But I do not know how much I should do and is it realistic to aim level B2?
Comment: @ChristopheStrobbe Yes. But this is minimum. Because I am willing to dedicate a lot from the rest of my day, but of course in a realistic manner.
Comment: @PeterMasiar The question is answerable based on requirements that language schools and test centres provide about expected number of classroom hours that you need in order to pass the test. These are estimates, but still objective because based on the experience of these schools and test centres.
Comment: @ChristopheStrobbe - I assume that language school expects some significant effort outside of the classroom, which might not be possible if OP has full time job working on some other projects, and 20hr/week is like a hobby. If learning Russian occupies most of the waking hours, it is different.
Comment: @russianfrom0toB2 If you are talking about ТРКИ-II, sadly, I don't think this is realistic -- unless you are just fantastic in languages, already speak a Slavic language (not sure bout Turkish), or are willing to "die trying" without any other work or hobbies--I would think 90+ hours/ week would be necessary. ТРКИ-I *might* be doable, but even this would be quite a feat. That said, extreme efforts yield extreme results, and if you do manage to pass, I'd certainly like to hear how you did it. Please keep us posted. Good luck!
Answer: The Test of Russian as a Foreign Language or TORFL has six levels that are mapped to the six levels of the CEFR. So the Second Level Certificate (TORFL-II) in the TORFL should correspond to B2 in the CEFR.
According to the Russian Language Centre in the UK, which also administers TORFL tests, the number of hours of study required to pass TORFL-II is roughly 1100. (Russian online gives slightly lower numbers: "Ca. 820 Stunden ["hours"] + 120 Stunden Berufssprache ["hours professional langauge"]".)
So if you attend a course of 20 hours per week, you would need roughly 55 weeks or just over a year to pass the test. However, the course participants in the UK don't have the advantage of immersion that a course participant in Russia has, so in the latter case, 52 weeks may be feasible.
Answer: In addition to Christophe Strobbe's answer: because you can dedicate another 60+ hours per week to your study of Russian, as you disclosed in comments, it should be feasible.
Consider immersing yourself as much as you can in Russian, 7 days a week. As soon as feasible, find a tandem partner for language exchange (trading your English for Russian), so you can get few more hours of conversation in Russian every week. You don't need a conversational level of Russian for that, leverage your English.
I had similar experience (I had better fundamentals, not starting from zero like you do) and after a year, I dreamed in Russian.
Answer: In my personal opinion...  Studying for 20 hours/week for one year in a classroom is not going to be enough to reach B2 level.
For example, there are programs to prepare foreign students for studying in a Russian University. Programs like this one typically last one academic year with 6-8 hours/day (30-40 hours/week) of studying Russian, and professional subjects (e.g. physics, math, chemistry, etc.) in Russian. After completing such program many students speak at B2/C1 level, but not everyone.
However, immersion in the environment is a very important positive factor in your case. Try to use it to your benefit.

Walk around the city, read the street signs, billboards, etc.
Talk to people in the school, and outside the school. Most likely you will have to communicate with locals in grocery stores, and such.
Watch movies. Action movies often contain simple and predictable dialogues.

From my observation of adult immigrants to North America.  After two years of living and working here, almost everyone can speak reasonable English independent of cultural background, or foreign language they learned in school.
Answer: I am the director of Russificate school. Yes, we do offer official TORFL exam sessions every month. Hundreds of students already received their certificates through us. We always respons to messages on WhatsApp, email and on Facebook messenger. You can check the details here: www.russificate.com (TORFL)
We also have many free sample tests for self-preparation where you can check your level.
Best reegards,
Yulia Amlinskaya.
Answer: The Google (English) and Yandex (Russian) web browsers have implemented the Microsoft multi-lingual translator apps.  The Google translator (translate.google.com) will accept both English, Turkish, and Russian characters, returning answers in both English, Turkish, and Russian as well.  On input, Google converts English characters to Russian characters; it may do the same with Turkish characters as well.  Google's grammar checker also flags incorrect spellings with a "Did you mean?" followed by a suggested correction.  Google also has a two-speed (speaking speed, learning speed) for both input and output, a real advantage when learning not only reading and writing, but also speaking Russian.
Like Google, the Yandex web browser has also implemented the Microsoft multi-language translator.  The Yandex translator (translate.yandex.ru) also has pronunciation, but apparently only for Russian language inputs and outputs.  To my ear the Russian pronunciation in Yandex is much more lifelike than Google's.
The Yandex translator (Переводчик)can also be accessed from the Yandex browser's home page -- it's included in the list of options above the search box on the home page.  Additionally,the Yandex web browser (yandex.ru) has many interesting features for a student in and of itself.
Both apps have excellent dictionaries, including multiple meanings of words, phrases, and sentences, along with synonyms and antonyms for the definition.
Once one has learned how to use the many advantages of the two translator applications (along with their individual peculiarities as well) the two translator apps can be exceptionally useful for students learning one or more languages.
Comment: Someone down-voted my answer without leaving a reasonable or intelligent comment on why they down-voted my answer.  It happens quite often when I describe the many advantages of having not just one, but TWO!! "personal tutors" -- translate Google and translate Yandex -- at  language students' beck and call, helping them with all types of vocabulary and grammar questions for both source and target languages.  In todays multi-lingual environment, computers are most  definitely the alternative to old-fashioned, conventional, 'brick and mortar' classroom, book, and immersion self-learning methods.
Comment: Another aspect of computer-learning is the ability to use Google Maps to visually go to a geographic location like St. Petersburg, Russia.  A sophisticated street map of that city is available, with streets and locations given in both transliterated and Cyrillic Russian.  One can even do a visual walk-about in St. Petersburg, "walk" along a street, look into store windows, turn corners, "stand" in a bus queue, look at up and down at buildings and monuments, read signs and posters, and otherwise be an "armchair tourist" in that city and its environs.  All by computer.
Comment: For "Google Maps" go to maps.google.com.  It's amazing where in the world one can go to on "virtual visits" to places like Nagoya, Japan, Berlin, Germany, and Honolulu, Hawaii.  You are able to see the many sights (dotted by Google for you to click on to see ), walk the streets, see and read signs, 'walk' around inside buildings, see local people.  Even dodge cars when you 'walk' across intersections!  Try it; the 'virtual' world is out there for you to see for a better perspective in your language learning studies
Comment: You wrote how and why certain online software is useful. You did not answer the question that was asked, which was about the feasibility of learning Russian to a certain level with certain amount of teaching.
Comment: @Tommi Brander:  There are two questions asked in the author's query.  I ignored the first because the author  asks for a personal opinion regarding the author's capabilities.  The second question is the one I responded to: "Any type of help will be great."  Since "Language Learning" is this forum is about, I answered accordingly.  From the facts given by the author the appropriate SE forum is not this one.  The author really should have posed the question in one of the two SE Russian language forums, to wit:  "Russian Language" and "Руский язык".
Comment: "Any type of help will be great." is too broad and should probably be removed from the question. I guess I glossed over it.