After beating the Portal 2 single player campaign, how do I listen to the ending song again?

Question: Is there a way to listen to the ending song again after I have beat the game?  Other than the obvious way of beating it again.
Comment: @Raven-Dreamer should have bought it on the PC then :P
Comment: I assume it's on the internet somewhere. Youtube probably.
Comment: I'm sure it is on youtube as well.  I was wondering if there was a way to get to it in the game.
Comment: @Air - 360 users can't access the console.
Comment: I don't know if this works for xbox but on the PC you can do that by typing "map sp_a5_credits" in the console
Answer: Youtube's probably your best bet.

Alternatively, you could manually save your game directly before the final boss fight. You'll have to beat the boss and go through the ending cutscenes again, but it's shorter than beating the whole game an Nth time.
Answer:
PC ONLY :(

If you want to see the whole ending sequence and song, in-game, open the console ~ and  run the command map sp_a5_credits
You can extract the music as well using this method.  Or you could probably just download it, the music's plastered all over the internet anyways.
Comment: "You can extract the music as well using this method." Not for the Xbox 360 version you can't.
Answer: Valve is making the soundtrack from Portal 2, entitled "Songs To Test By", available to download free.
You may need to wait for the correct volume to be released, but it will (should?) be there eventually.
Update: Soundtrack Volume 3 was recently released and includes "Want you gone". Plus there is a link to it as a ringtone.
Comment: Specifically, it's `Portal2-13-Want_You_Gone.mp3` from Volume 3 or the Complete set.  As a side note, the singing turret is `Portal2-12-Cara_Mia_Addio.mp3` from the same volume.
Answer: If you want to watch the credits again, you can select Single Player, then Developer Commentary, then scroll all the way down to "Chapter 10 - The Credits".
Then the credits and the song will roll again!
Answer: You can go to "New Game", scroll all the way through the levels again, and press "End Credits" or just download it on Spotify.


If the radio fails, can a pilot contact the tower by cell phone?

Question: Is it an accepted practice to notify the tower of a radio failure by cell phone, and use the cell phone as a radio, or are there other ways of dealing with radio failure?
Comment: I suspect this depends on the specifics of the situation, but you could certainly try to contact them by phone, but be prepared that they might not answer. If your intention is, for example, to land at a class D airport and you've not yet entered the airspace, you could fly _over_ it until you get their attention (they'll shoot you with a light gun)... then land when they clear you via light signals.
Comment: @mah Might want to spin your light signals comment into a full answer, I think that's what he's looking for.
Answer: As I pointed out in another answer of mine, it is not legal to use a cell phone in flight, and as another answer to the same question says, it really doesn't work very well anyway..
Now, if the pilot has an emergency, they can exercise the emergency authority of the PIC as allowed in 14 CFR 91.3(b) to go ahead and use the cell phone.  If it is just the radio failure though, that isn't usually an emergency since there are other procedures in place for radio failures.
Radio Failure Procedures
AIM 6-4-1 contains the procedures to use in the event of a radio failure.
Basically, if the pilot is in visual conditions (VMC) and can remain that way, they should fly VFR (visually) and land as soon as practical.  If they can't remain in VMC then there are a number of rules which spell out the route and altitude that they should fly, as well as when they should start an instrument approach.
Once they get to an airport they will still need to get clearance to land if it is a towered airport.
AIM 4-3-13 covers that, and basically the tower will communicate with the pilot via light gun signals:
Comment: ...and with the noise in a light GA cockpit that light gun is going to be WAY easier to understand than a voice on the other end of a cell phone anyway, unless you have an audio panel in your plane that connects to your cell phone via bluetooth or a cable. If I take my headset off with the engine running in a Piper or Cessna there's no way I'm going to be able to carry on a phone conversation with someone :-)
Comment: @flyingfisch Yeah, there usually isn't really much communication needed once you are close to an airport.  They need to clear you to land and clear you to taxi to the ramp and that's about it.  Pretty simple and no need for a phone call.
Comment: wow, didn't realize that light signals would trump cell phone...
Comment: Technical nit: Actually, the pilot's authority under 14 CFR § 91.3(b) would not authorize the use of the cell phone, since it only allows deviation from 14 CFR § 91 and the cell phone restriction is 47 CFR § 22.925. The pilot-in-command (or person authorized by the PIC) does appear have the authority to use the phone in if in distress (that deliberately has the same meaning in radio-communications and aviation) under 47 CFR § 80.311, which although sub-sectioned under Maritime Service has apparently been carefully worded to apply to aircraft and other vehicles too.
Comment: Based on the link I found for 47 CFR - "The use of cellular telephones while this aircraft is airborne is prohibited by FCC rules, and the violation of this rule could result in suspension of service and/or a fine. The use of cellular telephones while this aircraft is on the ground is subject to FAA regulations."  The FCC also recognizes emergency situations and allows for otherwise out of band emissions in those cases.


Has there been any commentary on "Soundarya Lahari" by any scholar from Sri Shankaracharya's lineage?

Question: This page describes Soundarya Lahari as being authored by sage Pushpadanta and Adi Shankara. While there are many who believe this to be incorrect attribution, I am more interested to know if any scholar or acharya from the sampradaya of Sri Adi Shankara has written a proper commentary on this text. If yes, would appreciate being given the exact source material, online or offline.
Answer: S.S.S. Shastri and T.R.S Ayyangar have authored a commentary on the Soundarya Lahiri in English. You can download it here.
Comment: @Ambi Ok , Yes , hope that we will get some more answers after your clarification . :-)
Comment: @SuryaKantaBoseChowdhury I would disagree on that it is an advaitic work. It is a shakta work whose import has been extended extensively to cover for advaitic purposes.
Comment: @SwiftPushkar well, I didn't narrow down the scope to just pontiffs. Besides, one the authors of the book shown in the answer seems to be from an advaitin and the other a vishishtadvaitin (at least by their names). I will give this a couple more days to see if some more answers are given.
Comment: I don't think any commentator on the Soundarya Lahiri would write from any perspective except Advaita. Because Soundarya Lahiri is purely an Advaitin work.
Answer: A total of 36 commentaries is said to have been composed on the Saundaryalaharī, out of which the one composed by Lakṣmīdhara is the most popular one. Here is a link for 9 commentaries, including the one by Lakṣmīdhara. Here is another link to its exposition in English by Svāmī Tapasyānanda of the Rāmakṛṣṇa Maṭha.
Answer: Those who say that Saundarya Lahari is an incorrect attribution to Adi Shankaracharya should study it's inner essence before commenting upon it. Saundarya Lahari is such a wonderful work comprising of extreme and complex grammatical tenets that nobody apart from the great Adi Shankaracharya could compose it. However, for the purpose of debunking some baseless accusations about it's authorship by Adi Shankaracharya, we need a corroboration.
A great Tamil Shaiva poet named 'Kaviraja Panditar (998 - 1045 CE)' has penned a commentary on each and every single verse of Saundarya Lahari way back in 11th CE itself which is available here
Even in Prapancha Sara tantra, Padmapadacharya while commenting upon the 11th Chapter of 'Tantra vimarsha' quotes few verses of Saundarya Lahari glorifying the Supreme mother of Universe. So there's nothing erroneous in attributing Saundarya Lahari to Pushpadanta Mahagandharvaraja and Bhagavan Adi Shankara.


tif tfw to GeoTiff

Question: How do I combine a .tif file with a .tfw file to create a GeoTiff? There are many answers telling me to use gdal, but I have no clue. So can someone provide a step by step example of how to do this please?
Comment: You should edit your prior question rather than re-asking it. If one of the answers there suggested using gdal and you wanted to go that route, you could comment on that answer to request step-by-step instructions and the answerer could then edit their answer with more detail. As it stands, an answer was given for ArcGIS at your first question as both an answer and a comment referring to another question where the same answer was given. There was also a link to yet another question that has an explanation of what the tfw file *is*.
Comment: this answer it http://gis.stackexchange.com/questions/87642/how-to-convert-a-tif-with-tfw-to-a-geotiff
Comment: I understand this is a duplicate question, in fact there are many duplicates. Can you tell us why you have a problem with GDAL? Is it that you're unsure about command line?
Comment: @MichaelMiles-Stimson Yes, that's why. I searched online for examples or explanations but everything I find just tells me a line of code that I should use, though I don't know how to get started. Thanks for your answer below, I'll give it a shot.
Answer: If you're scared or unsure about using command line tools like GDAL_Translate then there are other ways to do this.
If you have Esri products then you can use Raster to Other Format or Copy Raster, you can even export the image from ArcMap just by right clicking on the layer and select export then fill in the blanks and select GeoTiff.
If you want to use GDAL to do this then I recommend downloading and installing QGIS. This will give you a menu to export, which is just building the command line for GDAL_Translate. Go to the raster menu, select translate and a menu will come up:

Notice at the bottom is the GDAL_Translate command. This is from version 1.8, the new one might look a little different. There is also an option for batch mode which will convert a folder full of rasters!

tif tfw to GeoTiff


Can we Fire the button CLick event on Windowload In WPf C#

Question: i want to FIre the button Click event When My Window is Loaded..
How Can i Achieve it in Wpf?
Answer: Create a single function with the shared behavior in your window, then call that function from both your loaded handler and your click handler.
Answer: As per this blog post in WinForms this was really easy by just calling PerformClick(), but in WPF you can do it with Automation, however as a commenter mentioned it's really easy if you have access to the button to just use RaiseEvent.
someButton.RaiseEvent(new RoutedEventArgs(Button.ClickEvent));

But as previously answered, if you only have a single handler that needs to be notified, then simply call that handler method directly.
Answer: in you page_loaded event handler method, make a call to the click event like this:

_buttonName_click(sender, new RoutedEventArgs())
Comment: To clarify, this isn't actually calling the 'event'... It's calling the method (which happens to also be a handler for the click event). But yes, this is correct way to do it if we know this is the only handler we need to call to.
Answer: You could use Automation to do it aswell - I've seen this suggested some places as the more flexible/robust method to use, but it seems a bit heavy weight to me compared to just calling the method you already have directly.
Answer: Trgger this event on Button whic u wanted to click
button.performclick();


Tutorials/Books detailing JQUERY, AJAX, CSS (how technologies integrate)

Question: Any recomendations on how these technolgoies work together to create dynamic HTML pages would be beneficial.  I wanted to find one source of documentation which details the relationship between the above technologies.  Thanks in advance.
Answer: Honestly, I'm not sure that you're going to find one quality source to cover all of those subjects. They're all pretty distinct and you can go into great depth on each subject. I'm assuming that you're looking to learn/give someone else the tools to learn basic web development?
This site seems to accompany an Apress book and has some very useful CSS examples. http://cssdesignpatterns.com/
With HTML/CSS and learning JavaScript/CSS patterns, there's nothing better than just viewing sources/using Firebug or other developer tools to inspect sites and see how others have built things.
As for jQuery, you can use it without truly understanding the JavaScript underneath, but you will get much, much further in being able to create the sites that you want to create if you have at least a rudimentary knowledge of JavaScript proper. Though rather opinionated (in many spots this is a good thing) Crockford's "JavaScript: The Good Parts" is a solid intro to JS. http://oreilly.com/catalog/9780596517748/
Otherwise, you could pick up any intro to JS book - I'd recommend an O'Reilly book. There are other good ones I'm sure, but O'Reilly is almost always a safe bet. Looks like a JS/jQuery book is coming out next month if you can wait. http://oreilly.com/catalog/0636920015048
Any JS/jQuery book should probably cover AJAX. The API docs for jQuery at api.jquery.com are a great resource.
In terms of the relationship between these technologies: HTML should be thought of as the semantic context for your content that contains anchors (IDs, classes) for CSS to style elements and for JavaScript to alter those elements dynamically. jQuery is a JS library that allows you to write JavaScript more quickly and easily. AJAX, via JavaScript, allows you to load data sources into your page. This explanation is admittedly a bit of a simplification, but should be sufficient context to start with.


According to sedeprivationism, does a material pope have temporal authority?

Question: According to sedeprivationism, does a material pope (papa materialiter) have temporal authority?
Answer: John of St. Thomas (CURSUS THEOLOGICUS In Summa Thelologicam D. Thomas, Tomus VII, IN SECUNDAM SECUNDÆ DIVI THOMÆ, Quæstio I, DE FIDE, DE AUCTORITATE SUMMI PONTIFICIS, Parisiis Ludovixus Vivês, Editor, 1886, p. 207, sq.) seems to think a heretical pope can exercise (albeit illegitimately/tyrannically) temporal power:

[The Church] may defend itself, not by deposing him [a heretical pope], but by repelling him with force if he proceeds with violence or tyrannically, if, for example, he wished to do something against justice by the force of arms, one could repulse him with arms; and similarly, if he were to establish something against good morals he is not to be obeyed, because an unjust law does not oblige.


Can the second class refer to the second lecture?

Question: I'm not a native English speaker. So I'm a little bit confused about the difference among the class, course and lecture. And today, an English teacher educated in a very famous university in our country said that if you have three classes a day at school, you can't just say the second class to refer to the second one of them because the second class in English means to be subordinate, like second-class citizens. Hence, there are some disapproving meanings attached to it.
I was quite shocked to hear this, since it's almost the most common expression in my mind.
So I searched for it on the Internet, and found out that a course means a series of classes about a particular subject in a school, which means a course is more than one class, and a lecture would be more like a speech rather than a class, usually taken place in campuses.
Please tell me whether that English teacher's opinion is true or not.
Answer: The teacher is both right and wrong.
It is perfectly true that if you describe something as second class the implication is that it is inferior to something first class. However anything can be the second using it in a purely ordinal sense so the second class of the course is the one between the first and the third. If you want to avoid any possible doubt just say the second class of the day.
Comment: Hyphens help. My second class teacher of the day is not a second-class teacher.
Comment: Please allow me to ask one more question, which I didn't express clearly above. Is my distinguishment to the lecture, class and course right?  Sorry to bother you again.
Comment: Yes they seem OK. There are other words and I suspect US practice may be different from UK  so the full story may be quite complicated.

Can the second class refer to the second lecture？


System of six equations in real numbers

Question: Let $a,b,c,d,e,f$ be real numbers. Solve the following system of equations:
$\begin{cases}a+b=-e\\ ab=f\\ c+d=-a\\ cd=b\\ e+f=-c\\ ef=d\end{cases}$
I got stuck trying to solve this problem by decreasing the number of variables using consecutive equations. What I tried next was to subtract the first equation from the second one, obtaining $ab-a-b=f+e=-c\implies (a-1)(b-1)=-(c-1)$. Analogously we can get $(c-1)(d-1)=-(e-1)$ and $(e-1)(f-1)=-(a-1)$. Now multiplying these equations all togethes gives, that either one of $a-1, c-1, e-1$ equals $0$ or $(b-1)(d-1)(f-1)=-1$ and here's where I got stuck not being able to deal with the last case.
By the way, all of the first case in all possibilities gives one solution $(1,-2,1,-2,1,-2)$. I feel like the other one should give the zeros-only solution.
Don't know how useful are these approaches... I'd be very grateful for any help :)
Comment: I think I do not understand what do you mean by that...
Comment: It is not the solution though.
Comment: I doesn't however prove that these are the only solutions.
Answer: Eliminating the variables $$b,c,d,e,f$$ we get for $a$ the equation
$$(a-1)(a^6+a^5+2a^4+3a^3+6a^2-a+1)=0$$
and
$$a=b=c=d=e=f=0$$ is also one solution.
Comment: I see, but would you like to show me a sketch of the process of elimination?
Comment: Is there any smart way to do this?
Comment: I'd be really grateful for any explanation

System of six equations in real numbers


Is 'clothes' countable or uncountable?

Question: I can't decide if the word 'clothes' is countable or uncountable. The dictionary only writes - plural.
Comment: questions like this about English grammar or usage are off-topic in linguistics, but would be on-topic on either the ell or english stackexchange boards
Answer: Clothes, like (eye)glasses, pants, scissors, &c., is a plurale tantum—a word that only occurs in the plural. Most pluralia tantum in English are things that naturally conceptually come in pairs (two lenses in glasses, two legs in pants, two scissor-halves in scissors), but there are plenty of others—clothes, riches, remains, &c. Whether they're count nouns or not depends on how you define count nouns versus mass nouns, but in English they're generally considered mass nouns—they certainly behave like mass nouns in that you need measure words when you actually count them (three pairs of pants, not three pants).
The reverse is a singulare tantum—a word that only occurs in the singular. In English all mass nouns that aren't pluralia tantum are singularia tantum, and almost all singularia tantum are mass nouns—the only exception I can think of is a shambles.
(Even though this question asks about an English word I feel it's in scope because it's about a grammatical concept, not a usage question.)
Comment: Since most non-count nouns are invariably singular, it would make sense to include plural-only nouns like "clothes", "scissors" etc. in the count category. There are a fairly small number of non-count nouns that are invariably plural; these include "remains", "credentials", "genitals" and "proceeds".
Comment: @BillJ You've actually managed to find two more count nouns that are also singularia tantum. "Deal" is certainly a count noun (the fact that it can take an indefinite article is diagnostic), and "knowledge" is complicated because it can be a mass noun or a count noun, but as a count noun it's always singular (you can have a knowledge of something, but you cannot have multiple knowledges). "Regard" is a mass noun that can be used in the singular ("to hold in high regard") or the plural ("kind regards"), which is also neat.
Comment: Whatever your analysis, I don't think it's helpful to conflate "singulare tantum" with "non-count noun" and everything else as "count noun" as categories.
Comment: Under restricted conditions, "a" can combine with non-count singulars. I rather assumed you'd spot the appropriate senses of the items I listed. In "He wastes a great deal of time", "deal" is non-count. And "knowledge" is non-count in "Jill has a good knowledge of Greek", and "regard" is non-count in "I have a high regard for them". I didn't conflate singular-only with non-count. It just happens that the majority of non-count nouns are invariably singular, while only a fairly small number are invariably plural (e.g. "remains" "credentials", "genitals", "proceeds" etc.)
Comment: @BillJ The reason the indefinite article is generally taken as diagnostic in English is because it effectively behaves like (and goes back to) a numeral. Like I've said, different analyses certainly exist; none is universal, and if you want to argue about their relative merits the first step is for you to make your definitions explicit. Whatever your analysis, I can't see the sense in arbitrarily counting "remains" as a mass noun but relegating "scissors" to the count nouns, as you advocated.

Is 'clothes' countable or uncountable?


Raising and lowering operators

Question: $a^ta=n$ where $a^t$ is the raising operator. While doing the harmonic oscilaltor I encountered these. I could get that $n$ and Hamiltonian commute and if $|n\rangle$ the common eigenstate with eigenvalue $n$ then $a^t|n\rangle$ also eigen vector of operator n. From this they conclude that $a^t|n\rangle=c|n+1\rangle$
But how does this happen . Could someone explain the math?
How do they know that $a^t$  raises the eigen value by 1. So far we only got $a^t|n\rangle$ eigenvector of $n$ with eigenvalue $n-1$. Dont tell me like raising operators are like that they raise it by one. I wanna know the clear cut reason.
Comment: I would recommend reading the section about the quantum harmonic oscillator in "Modern Quantum Mechanics" by J.J. Sakurai.
Comment: Comment to the post (v4): 't' should be 'dagger'.
Answer: To show this we need the following properties:

The number operator is $\hat{n}=\hat{a}^{\dagger}\hat{a}$.
The raising and lowering operators obey this commutation relation: $[\hat{a},\hat{a}^{\dagger}]=1$.

It then follows that:
$$
[\hat{n},\hat{a}^{\dagger}]=[\hat{a}^{\dagger}\hat{a},\hat{a}^{\dagger}]=\hat{a}^{\dagger}[\hat{a},\hat{a}^{\dagger}]+[\hat{a}^{\dagger},\hat{a}^{\dagger}]\hat{a}=\hat{a}^{\dagger},
$$
where in the first equality we use the definition of $\hat{n}$, in the second the relation $[\hat{A}\hat{B},\hat{C}]=\hat{A}[\hat{B},\hat{C}]+[\hat{A},\hat{C}]\hat{B}$, and in the third the commutators $[\hat{a},\hat{a}^{\dagger}]=1$ and $[\hat{a}^{\dagger},\hat{a}^{\dagger}]=0$. This commutation we just derived implies that $\hat{n}\hat{a}^{\dagger}=\hat{a}^{\dagger}\hat{n}+\hat{a}^{\dagger}$.
We are now ready to turn to your question. The key step you are missing is to relize not only that $\hat{a}^{\dagger}|n\rangle$ is an eigenstate of the number operator $\hat{n}$, but that it is an eigenstate with eigenvalue $n+1$. To see this, consider:
$$
\hat{n}(\hat{a}^{\dagger}|n\rangle)=(\hat{a}^{\dagger}\hat{n}+\hat{a}^{\dagger})|n\rangle=(\hat{a}^{\dagger}n+\hat{a}^{\dagger})|n\rangle=(n+1)(\hat{a}^{\dagger}|n\rangle),
$$
where in the first equality we use the relation we derived earlier for $\hat{n}\hat{a}^{\dagger}$, in the second we use the eigenvalue equation of the number operator $\hat{n}|n\rangle=n|n\rangle$, and in the third we simply re-organize the expresssion.
So what does this mean? The state $\hat{a}^{\dagger}|n\rangle$ is an eigenstate of the number operator $\hat{n}$ with eigenvalue $n+1$. We can write an eigenstate of the number operator with eigenvalue $n+1$ as $|n+1\rangle$, so this means that
$$
\hat{a}^{\dagger}|n\rangle\propto|n+1\rangle.
$$
Comment: @ramAN if you want to call it "labelling" that is fine, but the key is that they have the same "label" because they are representing the same state (up to a constant).
Comment: Why the last step holds ??? That was my question
Comment: @ramAN: there are two points to the last step. The first is that we give the name $|m\rangle$ to an eigenstate of the number operator with eigenvalue $m$. Therefore, if $m=n+1$, we call the eigenstate $|n+1\rangle$. The second is that you have shown that $\hat{a}^{\dagger}|n\rangle$ is an eigenstate of the number operator with eigenvalue $n+1$. Put together, these two observations imply that $\hat{a}^{\dagger}|n\rangle$ and $|n+1\rangle$ must be the same state (up to a constant). Hence your result.
Comment: Is it just labelling then??
Answer: Use $[a, a^\dagger] = 1$ here like this:
Since you agree that $a^\dagger|n \rangle$ is an eigenstate of $a^\dagger a$, it means
$$
a^\dagger a (a^\dagger |n \rangle) = \lambda  a^\dagger |n \rangle\tag{1}
$$
Now $a^\dagger a  a^\dagger = a^\dagger(1+a^\dagger a)$, therefore (1) gives $\lambda = n+1$ by using $a^\dagger a|n \rangle = n |n \rangle$, which is the definiton.
Therefore, $a^\dagger |n\rangle$ is eigenstate of $N=a^\dagger a$ with eigenvalue of $n+1$, and must be therefore proportional to $|n+1\rangle$.
Answer: The operator $\hat n$ gives as eigenvalue the energy level of a given eigenstate. If you apply it to $a^\dagger|n\rangle$, you get
$$\hat na^\dagger|n\rangle=a^\dagger a a^\dagger|n\rangle=a^\dagger (a^\dagger a+I)|n\rangle\\\quad =a^\dagger|n\rangle +a^\dagger (a^\dagger a)|n\rangle=a^\dagger|n\rangle + a^\dagger \hat n|n\rangle$$
Then
$$\hat n a^\dagger |n\rangle= (n+1)a^\dagger|n\rangle$$
So if $\hat n|n\rangle=n|n\rangle$ and $\hat n a^\dagger|n\rangle= (n+1)a^\dagger|n\rangle$ it means that $a^\dagger|n\rangle\propto |n+1\rangle$

Raising and lowering operators


C++. multi-threaded bottle necking into a single threaded applicatin with lists

Question: I have a multi-touch application. It has 3 ccv applications sending udp packets to it. The application created receives all of these packets via ofxTuio which is mulit-threaded. These touches are then coming into the code we wrote on a single thread. We have display objects. They each have a list containing pointers to all of the objects they contain. For example we have written, onEnterFrame, addChild, removeChild; functions similar to the display list syntax you would see with actionscript. We, however, are getting iterating errors (concurrency) issues on the object's list because of the multi-threaded tuio events. How do we prevent this from happening. It seems as though locking (mutex) would not be right because these lists are not being accessed on multiple threads. I have created a custom queue for this list where they never iterate while objects are being removed or added to the list with a couple booleans and some extra lists for queueing. I suspect people have run into things like this, whats proper practice?
Answer: Flags aren't enough if you have multiple threads. Use a mutex or some other critical section to lock access for reads and writes. That's what they are for especially if you have any asynchronous or unsolicited events.
Answer: Use mutexes or atomic compare_and_swap instructions to make your data structures thread-safe.
Answer: If you are using the std::list anything but removing from the list will not invalidate iterators, in fact you have to be iterating the element being removed for this to pose a problem.  If you can structure your algorithm to handle it this way on the single thread this may be enough.
I'm curious as to what kind of iterator errors you are getting, are you getting incompatible errors?  How do the display object's get their lists?  Via this Queue?  Once the object has the list can the list be changed?


Preventing the call to default.xml

Question: I have default.xml overridden into my custom_theme but is actually an empty file(need not worry about the content).
I want to prevent magento 2 from calling this empty file so as to improve the system performance from the optimization perspective.
Please help.
Thanks in advance!!
Answer: There is no need to prevent Magento to load your overrided layout, that would be against logic and this is what we call: Magento Fallback System.
Since you have placed your default.xml in your current theme, it means that you tell to Magento take this file first, and after you want to tell him don't take it ! it doesn't make sense.
When you override or extends some layout, according to the Magento Fallback System, Magento collects layout files in the following order:

Current theme layouts: <theme_dir>/<Vendor>_<Module>/layout/
Ancestor themes layouts, starting from the most distant ancestor, recursively until a theme with no parent is reached: <parent_theme_dir>/<Vendor>_<Module>/layout/
Module layouts for the frontend area: <module_dir>/view/frontend/layout/
Module layouts for the base area: <module_dir>/view/base/layout/

So if you don't want Magento load your default.xml file, remove it, it has no utility and still less impact on performances.

More informations in Magento Devdocs
Comment: Yes absolutely, got your point.  Assume that I have removed my overriding file then how do I prevent the call to the original default.xml present in the module.
I had overridden the particular file to remove a block but nevertheless, the file becomes empty. Overriding is for the reason so that changes remain intact on system upgrade. But now I realize the fact to not override the file, but not give a call itself to achieve the functionallity which I would achieve by commenting a snippet.

Preventing the call to default.xml


Wrongly place on sex regristry

Question: I found one my friends listed on the sex registry. He is incarcerated. He was shocked. He has never been tried, convicted or served time for a sex crime. Alot of paperwork and finding info he is now off. However he was on it for 22 yrs. Can he sue? I'm am 200% sure its defamation and slander. I'm just thankful he'd off the registry but what about  the time, he lost seeing his grandkids growing up plus his own kids.  Ty
Comment: If he didn't even know he was on the list how could it have kept him from seeing his grandkids?
Comment: To be honest, his children might have just told him they don't want him anywhere near the grand children (because they found he was on a registry), without telling him the reason.
Answer: If defamatory misinformation were put on a sex offender registry, there is little chance that the defamed person can sue for damages. These registries are government operations, and the doctrine of sovereign immunity prevents the government from being sued, unless they explicitly give permission to be sued over some wrong. There are 50 states and the federal government to consider so it matters where the error is, but governments generally immunize themselves against liability for errors in these lists. E.g. Texas law (Art. 62.008-.009) immunizes various individuals and institutions in connection with the sex offender registry.
Because there is no legal notification requirement whereby a person convicted of a "sex offense" must be notified that he is now a statutorily-defined sex offender, a person especially one still incarcerated may be unaware of his status. Public urination is an example of a surprise sex offense. Your friend's being surprised doesn't mean that the information (formerly?) on the registry was false.

Wrongly place on sex regristry


If I accept an offer, but then my company counters with a big increase, can I negotiate an increase with the offer I already accepted?

Question: So I have accepted an offer. I was not expecting my current employer to counter with such a big offer.  Can I bring that up to the company I accepted the offer from already to negotiate a better salary?
Comment: You certainly can, but going back and forth more than once is probably not a good idea. Also, only do it if you would actually turn them down to stay in your company.
Comment: contract signed?
Answer: I believe that using this as a leverage would damage your reputation from the perspective of the new company. It would show that you can easily break your agreements (you have already made a mutual decision in terms of salary). Also, hiring is expensive (training, adapting, etc) and the employer hopes that you'd stay for as long as possible. If you would come back with new demands then chances are that you would be leaving them soon and cause them problems with replacing you, time spent on your training wouldn't pay off, etc.
I've been in this situation and I know how tempting that is but you are better off not doing that :)

Regarding accepting a counter-offer:
Technically you can. Is it a good idea? Generally not.
See, your current employer already knows that you want to leave. They are offering a raise not because they suddenly realized how great you are but because they don't have a replacement right now. Giving you a raise to stay buys them some time to find a replacement. Once they have found it, they have very little reason to keep you there because chances are, you will try to leave again soon.
The only exception might be if you have expertise in some niche that very few people do. At the end of the day, everyone is replaceable.
Also, you made the decision to leave them so probably there is something else other than money that was bothering you. If it was only money and they rejected a raise, that just supports my previous point.
Comment: @SpaceDog sorry! Edited my answer
Comment: Although your advice is sound the question asks if it's a good idea to tell the new company about the offer and negotiate a better salary for the new position. There's no indication that the asker intends to accept the counter-offer and stay at their current company (and, you are correct, this is rarely a good idea in the long term although it does depend on the exact circumstances)
Comment: +1, although you might accept the offer of your current employer and might not leave soon after, your employer will always think you wanted to  leave once, and thus you could want to leave again at a later time.
Answer: Generally it's not a good idea to bring it up after you have already agreed on something. As an employer, people that go back on their word is a warning sign. It might just lose you the offer from your potential new employer.
What you could do, is mention that you did get a much better offer from your current employer but that you like the new company more and need a few days to think and talk things through with your significant other / a friend before you make a decision. That just might get your new employer to raise their offer without you having to go back on your word.
Comment: This is sound advice.  My concern would be that requesting a few days might give them a few days to realize they can find someone else to fill the role.  But I think this would be totally reasonable in the right circumstance.
Answer: If you have accepted an offer, you have accepted an offer. The situation is that you will work for your old employer until the end of your notice, but you have mentally switched sides. You are looking forward to your new job. If your old company now makes a higher offer, that is just annoying, they should have offered it before you looked for a new position if they think you are worth it. (And indeed it is a good rule never to go back and take the higher offer, because you will be a marked man. Except if you are a marked woman. Or just marked).
What you can do is carefully tell the new company exactly that, that you received a higher offer, and how annoying it is that they waited until you decided to leave. No mention that you want more money, or that you are excepting more. Be genuinely annoyed with your old company. The result should be that your reputation with the new company will improve, and there is a chance of an improved offer.
Andreas' answer is very similar but a bit more aggressive, which increases both the chances of getting a better offer, and the risk of annoying your new company and losing out completely. Your choice.


Is it generally advantageous to offset capital gains with losses?

Question: Related to these two questions. My question is, if I have $1000 in short-term capital gains and, for the sake of simplicity, say I would have to pay a 20% capital gains tax - $200. Is there any reason I shouldn't sell off my worst-performing (this is to mean "they haven't panned out as expected" not "its having a bad quarter and I expect it to rise in the future") stocks until I've reached $200 in capital loss?
Answer: I actually do the logic the other way around.
In the account where I do my trading, once I no longer believe an investment can be profitable, I sell it.  Similarly, if I have an investment where I believe the future is flat or negative, I'll generally just sell it.  It's really about whether you think the investment has potential anymore or not.
By the end of the year if my trading transactions result in a net-negative, I'll trim some winning positions to absorb or partially absorb the losses.
Obviously the best outcome is never have losing trades, but losses are a reality of trading.  I wouldn't sell losers to cover offset gains for tax purposes, sell losers because they're losers, and trim winners because you can do so tax free.

I just noticed the math in your question.  Simplistically, losses offset gains, then your tax liability is calculated based on your net gain (if any).  If you have $1,000 in capital gains, you would need $1,000 losses to reduce your taxable gain to zero.  If you have a $1,000 gain and a $200 loss, you would have a net gain of $800 and would still owe $160 in taxes (based on your 20% tax rate assumption).
Comment: Thanks for that addendum on the math, was also something I was confused about but didn't want to make two questions
Comment: Note that the "wash sale" concept only applies to losses, not gains, so you could immediately buy back what you sold for a gain if you want to keep it, and now you have a higher cost basis such that future taxable gains will be smaller
Comment: Might be worth noting that when offsetting capital gains, that you start with like offsetting like, in terms of long-term and short-term. E.g. short-term capital gains are first offset by short-term capital losses, and long-term capital gains are first offset by long-term capital losses. If there are more losses in a bucket than gains, then those losses can be applied to the other bucket, but you must 0 out the same bucket first. Easiest here is to enter the info correctly into you favorite tax software and let that do its job of figuring it all out.
Comment: @yoozer8 that's a great point!
Answer: Yes. If you have investments that you are sure you will make a loss on when you sell them, you should sell them in a year when you also have capital gains.
This is because capital losses can only be offset against capital gains.
So if you have investments that are down $1000 and never going to grow, and you sell them this year (when you have made $1000 elsewhere) then the gains and the losses offset each other, meaning zero total capital gains tax.
If you wait until next year you may find that you have zero capital gains.  In this case you don't get the 20%*$1000 refund from the losses. But you still paid your 20%*$1000 in tax this year. Even if you make some gains next year you may find that you have more losses than gains, in which case you still don't get the benefit of the losses.
Your country may allow shifting gains and losses around by a few years, in which case this advice may apply only somewhat.
I would rephrase your statement as "it is advantageous to offset capital losses against gains".
Answer: In general, I don't think there's anything to be gained by this strategy.
Yes, by selling a stock that's lost money you can offset your capital gain and so reduce your tax for this year.
But suppose you didn't sell the losing stock this year, and instead sold it next year for the same price. Then you'd have the same loss, and it would reduce your taxes for THAT year. Either way, your combined taxes for the two years would have the same total.
Unless you have some reason why you want to reduce your taxes this year as opposed to next year, I don't see any benefit. I'd see the sale of each stock as a separate decision. Each one is either wise to sell this year or it's not, considering how much it's gone up or down in the past, anticipated gains or losses in the future, how much it would cost you or gain you on taxes ... whatever other factors you may consider.
You may want to think about what your marginal tax rate is likely to be in the future compared to today. Most of us have generally rising income, and therefore tax bracket, from year to year. So it makes sense to take gains sooner, when you'll pay less tax, and losses later, when they'll save you more tax. Well, until you hit retirement, when you're income likely falls sharply. If you're near retirement you may want to postpone gains and accelerate losses.
And of course there may be reasons why you want some cash NOW, like you're planning to buy a house or put your kids through college or whatever.


Guitar pickup coil , how far from strings?

Question: Looking for answers to this question , I found hundreds of discussions of the importance of magnet pole height / closeness with regard to the strings ( fairly obviously , close if you want it loud but not too close) but nothing about how close to the strings the coils themselves should be or the difference that changing coil distance makes on tone and volume. It seems it should be equally important , or more so. If you have adjustable polepieces and have moved the magnets as near the strings as you feel able without choking the vibrations , you could still increase (or decrease) output and alter tonal characteristics by changing their relative position.
Comment: Not so sure about the "duplicate". The poster asked about the influence of the the height of the pole pieces w.r.t to the tone; not the distance of the pickup as total. Maybe a clarification of the original question might help.
Answer: It doesn't really matter.  The coils produce voltage according to the magnetic flux changes through them, and the magnetic circuits are closed highly magnetically conductive material except for the part completed by poles and strings and the air between them.  Just where on the closed part of the magnetic circuit the pickup coil sits is irrelevant.
Comment: But the theory as I read it says that the magnets affect the magnetism of the strings through their lines of flux , and the movement of the magnetised string creates varying flux through the coil which in turn produces a voltage. So that is the strings affecting the coils across the air gap rather than disturbing the flux within the body of the magnet. So the flux changes around the coil would be greater if the coil was nearer to the moving string. Or have I got that wrong?
Answer: There are some sources that investigate the effect of different heights, strengths and string material when it comes to measuring the effect on the tone and volume [most namely M.Zollner "Die Physik der Elektrogitarre", although it's in German].
The relative positioning of the coil and and the magnets/the strings does not change anything in terms of physics. It's all about the change of magnetic flux inside the coil that will induce a voltage across the ends of the coil. The somewhat complex damping factors w.r.t to the input frequency relative to the output frequency are not affected. But in order to gain the same volume at a greater distance to strings [-- the same magnitude of the voltage oscillation at the coil ends] you'll probably need stronger magnets, which then will have a kind of feedback to the string oscillation, due to the stronger magnetic field strength.


What prevents a cover to be Galois?

Question: Let $f:X\rightarrow Y$ be a ramified cover of Riemann surfaces or algebraic curves over $\mathbb{C}$. My question is can one in terms of the ramification data of $f$, determine whether the cover is Galois or not. I am Specially interested in the following question: if $f:X\rightarrow Y$ and $g:Y\rightarrow Z$ are both ramified Galois covers of curves, when  $g\circ f:X\rightarrow Z$ is (or isn't) a Galois cover?
Answer: I assume that the surfaces are connected. Composition of two regular covering maps need not be regular even if the coverings are unbranched: A (usual) covering map is regular iff it is defined by a normal subgroup of the fundamental group. If you have a composition
$$
X \stackrel{f}{\to} Y \stackrel{g}{\to} Z
$$
of regular covers then $\pi_1(X)\triangleleft \pi_1(Y)$ and
$\pi_1(Y)\triangleleft \pi_1(Z)$. Hence,  $\pi_1(X)$ is a subnormal subgroup of
$\pi_1(Z)$. Subnormal subgroups need not be normal. However, if, say,
$\pi_1(X)< \pi_1(Y)$ is a characteristic subgroup then it will be normal in $\pi_1(Z)$. This is the simplest condition I know to ensure that composition of regular covering maps is again regular. The same applies to ramified covers once you remove branch points and their preimages.
Answer: The ramification data doesn't generally suffice to determine whether the cover is Galois.  If $f:X\to Y$ and $g:Y\to Z$ are ramified Galois covers, then usually $g\circ f$ won't be Galois, for instance because there will usually be a point $z$ of $Z$ which has two preimages under $g\circ f$ having different ramification indices.
Comment: Thanks. Your remark about $g\circ f$ sounds interesting. Why having two preimages with different ramification data prevents the cover to be Galois? is it s well-known result that the preimages of points in Galois covers should have the same ramification indices?
Answer: There are many automorphisms of $Y$ over $Z$. One can pull back the cover $X$ along any of these automorphisms of $Y$, producing a new cover of $Y$. If the composition is Galois, then these new covers are in fact isomorphic to the original cover - this is because the map $Gal(X|Z) \to Gal(Y|Z)$ is surjective. Taking a lift of an element of $Gal(Y|Z)$ produces an isomorphism between the original cover and the pullback.
The converse is also true. If such an isomorphism exist, they give us enough elements of the automorphism group of $X$ over $Z$ that, combined with the automorphisms of $X$ over $Y$, the cover is Galois!
So this explains why the two preimages with different ramification data will prevent the cover from being Galois. Because then the pullback of the cover along an automorphism which permutes those two preimages will not be isomorphic to the original - it will have different ramification data.
Comment: For a finite extension of number fields, the story is similar: ramification indices of all prime ideals over the same prime must be the same.  Also residue field degrees of all prime ideals over the same prime must be the same. Moreover, there is a converse result in this case: if, for each prime  downstairs, all prime ideals above it have equal ramification indices and equal residue field degrees then the extension is Galois, and the hypothesis on  ramification is actually not needed to get the  conclusion. Over C residue field degrees are all 1, so no information is stored there.
Comment: Consider the group of automorphisms of the trio $X => Y=> Z$ fixing $Z$. As a subgroup, it has all the automorphisms of $X$ over $Y$. The quotient group maps to the group of automorphisms of $Y$ over $Z$, and if this condition is satisfied, that's surjective. So the order of the group is at least $[X:Y][Y:Z]=[X:Z]$, so the cover is Galois.
Comment: Thanks. Was a beautiful argument, although I did not understand the converse argument that how the existence of such an isomorphism leads to Galois-ness property. possibly by enough elemnts of $X$ over $Z$, you means enough elements of $Y$ over $Z$ that combined with automorphisms of $X$ over $Y$ makes the composite Galois. But even in this case I don't understand why? I should think more on this.

What prevents a cover to be Galois?


While Torah means instructions, does this explain it equaling commands?

Question: How do Jewish scholars view the conclusion some make from the Hittite Instructions in The Ancient Near Eastern Texts Relating to the Old Testament  (3rd ed. with Supplement, p. i). Pritchard, J. B. (Ed.). Princeton: Princeton University Press. (1969). These were instructions of the Hittite king to various subjects.  Of course instructions from a king were more like commands than what we think of as instructions today.  Some claim that God used a form similar to a king instructing his subjects, a form that Israel would understand.  Of course, God's instructions are much more important than a kings'.
Answer: The Talmud describes some aspects of what happened at Mt. Sinai during the giving of the Torah in Shabbat 88a:

"The Gemara cites additional homiletic interpretations on the topic of the revelation at Sinai. The Torah says, "And Moses brought forth the people out of the camp to meet God; and they stood at the lowermost part of the mount" (Exodus 19:17). Rabbi Avdimi bar Ḥama bar Ḥasa said: the Jewish people actually stood beneath the mountain, and the verse teaches that the Holy One, Blessed be He, overturned the mountain above the Jews like a tub, and said to them: If you accept the Torah, excellent, and if not, there will be your burial."

From here we see that, yes, from the start, there was also an aspect of compulsion in keeping the Torah. At the same time, though, we know that it says in Deuteronomy 30:19:

"I call heaven and earth to witness against you this day: I have put before you life and death, blessing and curse. Choose life—if you and your offspring would live."

This is the aspect of us being given a choice, i.e., were we to want to do good, we should follow the Torah. Anything else is not good, but is equally a choice one can make.
So yes, it seems both aspects were present in the giving of the Torah and its commandments. As to whether there was done purposely by Hashem to be like certain kings of the era - I don't know. After all, the Israelites just came from centuries of servitude. I doubt the work commands they received were like instructions as though they had any choice in the matter.
This brings to mind a song by Rabbi Yehudah Halevi, author of the Kuzari:

עַבְדֵי זְמָן עַבְדֵי עֲבָדִים הֵם –
עֶבֶד ה' הוּא לְבַד חָפְשִׁי:
עַל כֵּן בְבַקֵּשׁ כָּל-אֱנוֹשׁ חֶלְקוֹ
"חֶלְקִי ה'!" אָמְרָה נַפְשִׁי.

Rough translation:

Those enslaved to time are slaves of slaves
The servant of the Lord he alone is free
So when every man requests his due
"My due is with my Lord!" says my soul.


Why SharePoint decrease width of TextBox set in InfoPath?

Question: I have a small problem with SharePoint. I customised my list in InfoPath and as you can see on first picture a Passport TextBox has 100% Width and is properly stretched from left to right side of my table. However, in SharePoint width of this TextBox is visibly decreased. I don't know why SharePoint is doing that. Changing font size, TextBox width and other action didn't resolve my problem.
InfoPath 2013 (ok):

SharePoint 2013 (not ok):
Answer: In InfoPath, the table cell and the text control are two different objects. Each object has its own width setting.
It can be quite tricky in InfoPath to select and format the text object instead of the containing cell object.
On top of that, any table cell in InfoPath can have padding settings that can impact the text in the cell. This is especially pesky and persistent when you use one of the Infopath template layouts.
So, in Infopath you need to check the formatting for the immediate text control and all the containers that surround this control.
It can be tricky, but it can be done.
If you are struggling, please share a sample file with a file sharing service for inspecction.
Comment: Thanks for help. I attained my goal in easiest possible way by deleting the top row and pasting TextBox to new one. Now it's obvious that problem was generated by deleted row in table. I still don't know what exactly causes it but it doesn't matter. Thanks again.


Why must the R-squared value of a regression be less than 1?

Question: Why must the R-squared value of a regression be less than 1? What does R-Squared value more than '1' indicate? Can a Regression Model with a Small R-squared Be Useful?
Answer: In a general linear model, R-squared is
$$R^2 = \frac{SS_{reg}}{SS_{tot}} $$
(Note: the above expression only holds if intercepts are included in the model -- see Whuber's comment below)
$SS_{reg}$ is the sum of squared differences between the regression and observations
$$SS_{reg} = \sum_{i=0}^n(\bar{y}_i-\hat{y}_i)^2$$
and $SS_{tot}$ is the sum of squared differences between the mean and observations
$$SS_{tot} = \sum_{i=0}^n(y_i-\bar{y}_i)^2$$

Why must the R-squared value of a regression be less than 1?

Under OLS regression, $0<SS_{reg}<SS_{tot}$, so $0<R^2<1$.

What does R-Squared value more than '1' indicate?

The important thing to note here is that $R^2$ is the ratio of explained variance ($SS_{reg}$) to total variance ($SS_{tot}$).  There's not always a perfect analogue to this in other models, and other quantities are often reported as $R^2$ (see Pseudo-R2s in logistic regression), however, these values are not always guaranteed to be between 0 and 1.

Can a Regression Model with a Small R-squared Be Useful?

This depends what you want to use it for.  If it is for prediction purposes, it is unlikely to be helpful, however, it is important to note that a large $R^2$ does not guarantee good prediction either.  It is simply a measure of how well the model explains the variability in the observed data.
Comment: It is not true that $R^2$ must be positive: that result requires an intercept term be included.
Comment: @whuber this is a fair point -- I've made a note in my answer addressing this.  Seeing as the question only asks why $R^2 < 1$, and intercepts are generally included by default in OLS regression, I'm hesitant to go into more detail in the answer.  I would have to start with $R^2 = 1 - \frac{SS_{res}}{SS_{tot}}$ and waffle on from there noting that $SS_{res}$ can be greater than $SS_{tot}$ ....
Answer: R squared is a measure of how far variation in the dependent variable is explained by the independent variable.
Its value ranges from zero to one.
If the independent variable explains none of the variance the slope of the regression line is zero and the R squared is zero
If the slope of the regression line is positive or negative and all observed dependent variable values lie EXACTLY on the line then the model explains one hundred percent of the variance in the independent variable and then the R squared is one.
If the slope of the the line is greater than or less than zero, the independent variable has some explanatory value for the dependent variable.  Depending on how closely the model (line) fits the observed data, R squared will have a value between zero and one.  If the observed data tightly fits to the model (line),   the sum of the squared errors will be small and the variance will be largely explained and the R squared value will be closer to one.
If the observed data is more dispersed around the line,  the model explains less variance in the independent variable and the R squared will be closer to zero.
A model with a low R squared is not useful because it indicates the variance in the dependent variable is not well explained by the dependent variable.
Comment: You're assuming one predictor and a straight line fit but the idea of $R^2$ is much more general.


JmsCorrelationId for async messaging send

Question: Are there any set norms for what a JMSCorrId should  be set to. My application is simply sending a message async to a queue and it doesn't care about waiting for any acknowledgement.
Answer: When the JMS client receives the reply message, it can match the JMSCorrelationID of the new message with the corresponding JMSMessageID of the message it sent, so that it knows which message received a reply.
The JMSCorrelationID can be any value, not just a JMSMessageID.
For example you can use JMSCorrelationID to identify the sender.
If you decide to use your own ID, be aware that you should not start an application-specific JMSCorrelationID with ID:. That prefix is reserved for IDs generated by JMS providers.
Typically implementation:
<code>public void onMessage(Message message){
try {
        TextMessage textMessage = (TextMessage)message;
        Queue replyQueue = (Queue)textMessage.getJMSReplyTo();

        Message replyMessage = session.createMessage();
        replyMessage.setJMSCorrelationID(message.getJMSMessageID());
        sender.send(replyQueue, replyMessage);
    } catch (JMSException jmse){jmse.printStackTrace();}
}
</code>


rotation curve in the innermost part of galaxies

Question: I read in Sofue's articles (1999) that he used a method to investigate the bulge of galaxies to obtain rotation curve of this part of galaxies. So my question is how could Vera Rubin et al. obtained the rotation curve in their article (1978), especially the steep increase in the begenning of the curve since in Sofue's article he seems to say it was rather difficult, at that time, to investigate galactic bulges ?
Comment: Could you be a bit more specific about the source? *Which* article by Sofue (there are 10 from 1999), and where in the article is this said?
Comment: For example in this article arXiv:astro-ph/9910004 (second sentence of the introduction). So my question is what was the Rubin's method for the inner part ?
Answer: So they are talking about different scales. Rubin is finding the rotation curve on kpc scales. And Sofue is talking about how hard it is to get the rotation curve in the central less than a kiloparsec. In the center you cannot use the same techniques as Rubin did.
Rotation curves of galaxies are most often measured by the gas speed. The speed of the stars can be used, but owing to dynamical heating over time, the stellar rotation speed does not indicate the true rotation speed of the galaxy as well as the gas speed.
When looking for the speed of something, astronomers will look for the redshift or blueshift of the stars or the gas which they are observing. So, they need to identify a gas, which will be present in all galaxies, which has a well known and easy to observe "line" in the spectra which will allow a velocity determination by seeing how red or blueshifted it is compared to that emission line in a laboratory.
Two such lines are H$\alpha$ and molecular CO (the one mentioned in that paper you've linked).
The H$\alpha$ line is an optical line at 656.28 nm. The CO lines are radio waves at 2.6 and 1.3 mm.
It looks like the Rubin+1978 paper took spectra of the H$\alpha$ lines, and from Figure 2, it looks as if they've collected spectra from various radii from the center. If you do it to many different points inside the galaxy at different distances from the nucleus, you can see how fast they are moving relative to each other.
That steep increase at the beginning of the curve usually occurs for around the extent of the bulge, a few kiloparsecs (as in this image from Rubin+1978).

It looks like they had a resolution of about a kpc, which would not tell you much about the center, except that the rotation curve is very high, very quickly (you assume the very center is 0 rotation):

Sofue+1999 seems to be talking about even more central than that, like the "central few hundred pc region" which will require a new technique.
A large limitation, as mentioned in the Sofue+1999 paper, is that HI is often obscured in the very centers (<0.5 kpc) of these galaxies by dust. Galactic dust, in general extincts shorter wavelength light much more effectively than long wavelength light. In this way, looking at the galaxy in longer wavelengths allows you to see through the dust. The HI line is much more easily erased by galactic extinction than the CO line at a longer wavelength. So CO makes it easier to look into the galactic central hundred parsecs than H$\alpha$. You can see this in the galactic extinction curve:

The CO line is in the radio band (mm range), a type of astronomy that was just picking up speed in the 1960s and 1970s. Having been predicted in the 1800s by Maxwell's equations, scientists were unable to observe any radio signals from the Galaxy until a serendipitous observation of Sagittarius A* by Karl Jansky at Bell Labs in the 1930s.
However, radio astronomy comes with a problem of resolution, the resolving power of a telescope is basically:
$\Theta = 1.22 * \frac{\lambda}{D}$
Where lambda is the wavelength of the observation and D is the diameter of the telescope. And, for reference, the distances to two galaxies from that rotation curve above are:
NGC4594 = 9.45 Mpc
NGC7217 = 15 Mpc
At the distances of these galaxies, we need to be looking in the right wavelength to penetrate, and we need enough resolution to get the rotation speed at maybe 10 parsec scales. This resolution, at 15 Mpc, is maybe 0.1 arcseconds.
$3600 * arctan(\frac{10}{15e6}) * \frac{180}{\pi} = 0.1375 arcseconds$
To get that resolution observing at the 2.6 mm you need for the CO line, you need a:
$1.22 * 3600 * \frac{180}{\pi} * \frac{2.5e-3}{0.1375} = 4581.48$
4.5 km telescope… Hmmmmm. A bit of a problem considering the unfortunate tale of the 300 foot telescope.

Then, computers to the rescue. Interferometry is an idea whereby one can use two telescopes to increase their resolving power. When combining their signals, they have an effective diameter of their separation. Of course, they are not equivalent to a single dish telescope of that diameter, because they collect far less total starlight.

The technique was successfully utilized scientifically as early as the 1920s, to resolve the star Betelgeuse. But it was difficult to use this technique in it's modern form, combining tens or hundreds of telescopes at once without the advent of computers which could handle the calculations in the 1960s and 1970s.
And now, the final piece. Interferometry grows much more difficult the smaller your wavelength. Interferometry is only possible if amplitude and phase of the incoming wave is recorded and recombined precisely. So an optical interferopeter needs: more precisely polished mirrors, more precisely measured separations, stable signal information transport from the dishes (fiberoptics), and more computing power to run more fourier transforms. While radio interferometry was performed in the 1920s, it took all the way until the 1990s to do optical interferometry, and it's still far from routine (see the Large Binocular Telescope).
So, to summarize:
1) To get a rotation curve of a galaxy, we need a molecular line that we can get a redshift or blueshift from. HI (optical) and CO (mm) are good choices.
2) The very centers of galaxies are obscured by dust, which destroys optical signals, but allows mm to pass, so CO is the molecule of choice for rotation curves of the nuclei of these galaxies, as H$\alpha$ signal is poor in the centers.
3) However, for a mm telescope to be able to spatially resolve small parts of the galaxies at the large distances of 10+ MPC in this wavelength, we need a telescope a few kilometers wide.
4) We can solve this with interferometry, but only recently has the technology to do interferometry at this wavelength been accomplished.
The first interferometer observing at this wavelength, the SubMillimeter Array (SMA; eight, 6-meter telescopes), opened to guest astronomers for the first time in 1990. The SMA was still being expanded at the time of the paper you linked.

These days, the Atacama Large Millimeter Array (ALMA) is just now nearing completion, and is focusing on the same wavelength range only with huge resolution and surface area (66 telescopes from 7-12 meters). They are collecting CO rotation curves to such precision that they claim to be able to estimate the central black hole masses of galaxies to 5%.

Stuff:
https://en.wikipedia.org/wiki/Astronomical_interferometer
https://en.wikipedia.org/wiki/Aperture_synthesis
https://ned.ipac.caltech.edu/level5/Fitzpatrick/Figures/figure1.gif
https://www.nrao.edu/whatisra/images/300ft-before.gif
https://www.nrao.edu/whatisra/images/300ft-after.gif
http://www.atnf.csiro.au/outreach//images/wallpapers/atcamorningsml.jpg
http://www.almaobservatory.org/
Comment: Thank you for your answer but if Rubin could measure H$\alpha$ lines in the galactic bulge, then why Sofue is saying "However, the distribution of dark-matter in the inner disk and bulge are not thoroughly investigated yet because of the difficulty in observing rotation curves of the innermost part of galaxies." ?
Comment: I've added a couple of things to my answer, hope that helps.
Comment: Thank you for this comprehensive answer. So do you mean that,in Rubin's curves, the steep increase is extrapolated towards zero or that if we zoom on the data we can see that it stops before reaching zero?
Comment: The Rubin method (optical, H$\alpha$ line) could not look into very center (~<1 kpc) because of dust. mm observations (CO line) can see into the center, but had poor resolution until the 1990s, which is why Sofue says it's hard. Yes, they assume the center to have a rotation speed of 0 km/s.
Comment: Sure thing. Feel free to mark it as answered if you think this might help some other people.


Open several instances of TeXStudio

Question: TeXStudio can open several tabs in one window which comes in very handy when one is working on project-preamble.tex and project-content.tex at the same time. But when I am working on several projects at the same time, it would be nice if I could open one window for all files in project1 and another window for all files from project2. I cannot get this done under my Linux Mint machine. TeXStudio always just switches to the instance which is already running. What can I do?
Answer: If you ask your terminal for texstudio --help it will show:
Usage: texstudio [options] [file]

Options:
  --config DIR            use the specified settings directory
  --master                define the document as explicit root document
  --line LINE[:COL]       position the cursor at line LINE and column COL
  --insert-cite CITATION  inserts the given citation
  --start-always          start a new instance, even if TXS is already running
  --pdf-viewer-only       run as a standalone pdf viewer without an editor
  --page PAGENUM          display a certain page in the pdf viewer
  --no-session            do not load/save the session at startup/close
  --version               show version number

Therefore you will see the option --start-always which exactly does what you want it to do.
Edit: As kdb notes in the comments you may encounter some issues with this option:

TeXStudio will not manage sessions across windows.
SyncTeX reverse synchronization (PDF to TeX) will not always target the correct window.
Comment: Sadly, `--start-always` has several downsides. The ones I noticed predominantly: (1) Automatic session management is largely lost. (2) SyncTeX with external viewers can't target a specific session.
Comment: @kdb Thanks for pointing it out. While these effects are quite logical and predictable I think it is worth mentioning and have included it into my post :)
Comment: If you have two editor sessions with separate start-ups It may be possible to sync the two sessions separately The Question asks for a Linux answer and my experience is predominantly windows and TeXstudio is called via  texstudio.exe so would need two copies  texstudio1.exe and texstudio2.exe such a system would be no problem for 1 copy of sumatraPDF if there were separate  -appdata settings files since one would inverse search to  texstudio1.exe "%f" -line %l and the other to texstudio2.exe "%f" -line %l the main issue is if the two TeXstudio.exes are competing for their own common resources

Open several instances of TeXStudio


Is there any way to see how many times your character has died?

Question: The question is pretty much in the title. After finally beating Hell with my Witch Doctor, I was interested in knowing if there is a way to look up how many deaths it took to get there.
Answer: Not yet, but it may be implemented soon, since they're going to add character profiles to the game:

Our first profiles release will include these two elements:

A career tab that displays all of your heroes, how far you've progressed in the Diablo III campaign, how many foes you've slain, the names and playtimes of your fallen Hardcore heroes, and more.

A heroes tab that shows off your equipment (including dyes, socketed gems, all equipment bonuses, etc.), your attributes and skills, the skills and equipment of your Followers, and more.

Presumably one of those two "more" will be your death count, since a similar counter is already present in WoW character's profile.
Answer: Currently, the answer appears to be 'no'. Here's to hoping they add a statistics tab to Achievements or add the stat to your profile.


Removing revisions on google code?

Question: How can I completely remove a revision from the SVN on google code's project hosting website? I would like to delete the revision from the website so nobody can view or access it.
Answer: Do a rollback of the change.
Answer: Unless things have changed since this answer was posted, it doesn't seem like it's really possible to do in SVN other than creating a new repository.
As far as Google Code goes, I don't believe they would let you remove anything, since afaik once something is open source, it cannot be made closed source (future versions can, but anything released remains open source).

Removing revisions on google code?


Flagging questions

Question: Not that long ago, I remember there being an option to choose a flagging reason that was somewhere along the lines of "You need to have done research or know at least something about what you're asking." It was under, I think, the "It should be closed for another reason..." line of flags. I recently had a flagged declined for this question. I had chosen the "Other" option, and left the notation that there was "Very little, if any, effort into the question." To me, it seemed as if he were writing the question, and didn't really care about giving any info, or even if he'd gotten an answer. So should I have flagged the question? If so, what option should I have chosen? None of the ones I had seen were, in my opinion, a solid choice for the flag. However, it was still a bad question, and needed attention brought to it.
Comment: The "other" reason goes to a diamond moderator, so no that wasn't the way I think. Usually I flag the "poorly researched" question with either "too broad" or "unclear what you're asking", depending on the case. If none apply... downvote
Comment: @Patrice:  Please don't use flags for that.  Just downvote it.  The system has measures in place to remove the really bad stuff.
Comment: Related: http://meta.stackoverflow.com/questions/257868/can-we-please-have-the-lacks-minimal-understanding-close-reason-back
Answer: The close reason that you are referring to that no longer exists was:

Questions asking for code must demonstrate a minimal understanding of the problem being solved.

This is not saying that the question lacks sufficient effort from the author.  It's not saying that the question lacks research.  Rather what it's saying is that the answer to the question would be beyond the author's comprehension, so even if we took the time to answer it, they wouldn't understand that answer because it's asking about concepts that require a certain amount of background knowledge.  Explain enough of the background knowledge for the answer to be understood would end up making the question "too broad".
It was there to avoid problems like what is described in this example
Sadly, people didn't actually use that close reason for those types of questions.  They mistakenly assumed that the close reason was there for what you described, lack of effort, unresearched, etc.  They were closing questions with this reason purely for reasons that aren't described here.  It ended up being removed as a close reason because it was being abused so much.
If you feel that a question isn't well researched, or doesn't demonstrate at sufficient amount of effort in being formed, you should be downvoting it, not voting to close.  If, as a result of that lack of effort the question ends up meeting an actual close criteria (i.e. unclear) then close it for that reason, not because of the amount of effort shown.
Comment: You're right, Servy. I think this was just my wanting to be more important than I really and to feel like I actually had more of a hand in things than I did.
Comment: Excellent answer. Does "closing bad questions" come up very often in meta stackoverflow?
Answer: The problem is that you flagged it as "Other" requesting a moderator to step in where the community cannot.  This is incorrect, you should use the standard closing votes/flags to close a question.  By using the canonical reasons, the question will go into the Close Review queue and other users in the community will take care of it.
Moderators should only be involved in things that the community can't handle - closing question is not one of them.
Your flag was rightfully declined by a moderator.
Comment: @MyCodeSucks It depends on the question. The one you flagged could have been closed as "unclear" or even "too broad". If a question doesn't fit in one of the canonical close reasons, then maybe it shouldn't be closed - downvote, comment, or move along. The mods have more important things to worry about, than closing questions.
Comment: @MyCodeSucks "Unclear what you're asking" or "Too broad" would be fine for something like that. Or off-topic "Should provide clear problem statement...blah blah"
Comment: With that being said, what would be the best flag to raise for questions like this?

Flagging questions


Why the 70-year exile and not more?

Question: Reading Jeremiah, it occurred to me that the Israelite occupation of the land, including the time of the Judges, was around 800 years from the time they crossed the Jordan. God says the period of exile is due to them not giving the land rest like they were supposed to do (70 years for the 420 years prior) but the timeframe in question only seems to cover the period of the kings. Does this mean they obeyed that particular mandate during the time of the Judges? Otherwise, shouldn't the exile have been a lot longer? TIA
Comment: The question would be improved by including quotations of the specific verses you are getting this information from (e.g. "God says …").
Comment: Note that the Babylonian exile was for the Kingdom of Judah only. The Kingdom of Israel had already been taken in exile by the Assyrians long before that (and for long after).
Answer: See https://lifehopeandtruth.com/prophecy/understanding-the-book-of-daniel/daniel-9/
This article quotes the Jamieson, Fausset and Brown Commentary. The 70 years was "the exact number of years of Sabbaths in four hundred and ninety years, the period from Saul to the Babylonian captivity."

Disobedience to the Ten Commandments was judged by forty years of wandering in the desert.
Disobedience during the times of the judges was punished by periodic oppressions by neighboring peoples like the Moabites, Philistines, Canaanites, etc.
The exile was specifically a judgement against the kingdom of Israel/Judah, which began with Saul.

The cited article makes an interesting point: there were two overlapping 70-year exiles.

Seventy years from first deportation to Cyrus' edict permitting return.
Seventy years from destruction of Solomon's temple until the construction of a new temple.

Why the 70-year exile and not more?


Chronic illness meds and trust

Question: I found a sick female orange tabby kitten 4 months ago. One eye was completely covered with the 3rd eyelid, upper respiratory issues and a high fever. She ended up hospitalized but everything came back normal or negative but they do believe it to be feline herpes. She has had to take a lot of medicine at home and when I give it she runs/hides from me for days. Will not come to me for any reason. I do try to act disinterested/bored to get her to let me pet her but she will just run away. When the meds stop she will continue the behavior for a few weeks and then will have moderate trust with me. But she ran a high fever again and had to be hospitalized over night again and need antibiotics and eye drop x 2 daily - she actually did pretty good with these. But they had me start the anti-viral med famciclovir - compounded liquid "bitter masked". It still must be terrible as she reacts very strongly when I give it. First scratching to get away and then heaves or throws up for about 10-15 mins then seems back to normal. I give 1 ml in a syringe aiming to get as far back in her throat. I do try to comfort her after swallowing but she is scared and fights to get away. This is given 2x daily on an empty stomach for 21 days. But after just 3 days she is not coming near me and I don't know how I'm going to keep this up.they estimated her to be 6 months when I found her and she should be almost 10 months now but only weighs 6.6 pounds and is very small. Still intact as she hasn't been well long enough for surgery and plan to wait until about a year since she is an only cat indoors. Specialty eye vet recommended removing the bad eye as it is blind and because it does seem to cause her some irritation - some gunk always around it and she paws at it occasionally. If I have to give her these meds - how will I get her to trust me? It will mean I have to go to her and corner her and block any hiding places that I cannot get into. Being scared like that must be awful for her. But when she's not sick she is very, very playful with me or anyone. Loves her toys. But right now will not engage with me for treat or toy.
Answer: Unfortunately, handling pets is like handling kids. Sometimes you do have to do something they won't like, and they may be grumpy about it. Youngsters in particular may object because they don't have the experience to know this isn't seriously threatening.
In the end, you just have to decide that "I don't wanna" is not an acceptable answer, give the cat the medical treatment they need, and trust that they'll forgive you. Which they will. They may continue to object to treatment, but they'll figure out that it's normal.
Rewarding them afterward with a treat, or extra cuddling, may help with that process. Like giving a kid a lollypop after they've had an injection, it helps them decide to accept the annoyance.
Comment: Some dog and cat treats come in tubes (like toothpaste), which I find to be extremely helpful in situations like this. The treats have a better smell than dry treats and the pets can associate you opening the tube with them getting treats. All our cats and dogs go bonkers for these tubes and cannot resist, even after a negative experience (like ear cleaning) when they actively avoid being touched by us.
Comment: @Elmy: I usually make those an interactive treat , slowly squeezing the tue for Hazel to lick directly. I know some folks have also found that their cats will happily eat pills with a dab if this stuff on them,though that may depend on how bad the pill tastes

Chronic illness meds and trust


Are commodities ETFs risky as commodities futures in needing margin calls and limited time to hold or they are like stocks?

Question: Are commodities ETFs risky as commodities futures in terms of needing a large ammount of balance and margin calls and limited time to hold, or they are like stocks?
Answer: An ETF is a fund. A fund has managers who are paid from your expense ratio, e.g. 0.95% of fund assets annually, in the case of the FTGC commodity futures ETF.
You are paying the fund managers to manage the messy aspects of futures, such as margin and expiration.
Answer: If you're asking if you need to use margin or have a large cash balance as collateral, the answer is no.
ETFs and futures are totally different. With futures, you do not "buy" anything upfront. You make a "paper" gain or loss as the futures price moves up or down. if you have a paper loss, you are sometimes required to deposit margin to make sure that you don't lose more than you have.
A "commodity ETF" is designed to also have exposure to commodities, and may use futures or other derivatives to do so, but you buy units upfront and have a gain/loss as the commodity goes up and down. You don't need to provide margin because you own units of the ETF that still have value, so there's nothing that you "owe" the ETF. If the ETF goes to zero you just lost what you put in.
So they are "like stocks" in that way, meaning you can only lose what you put in.
Comment: @huab Margin requirements only matter if you are buying the thing on margin. The warning is explaining you might be able to buy, say, a S&P 500 ETF with 10x margin, but a commidities ETF on only 2x margin.
Comment: @D Stanley why when I want to buy a commodity etf, my broker put this warning message : "Leveraged, Inverse, and Commodity ETPs
Not suitable for most investors. Investing in these types of exchange-traded products (ETPs) involves heightened risks, including higher margin requirements, leverage, derivatives, and complex investment strategies. These securities are designed for daily use only, and are generally not intended to be held overnight or long term. Learn more about trading these products"..this warning for example was for corn teucrium
Answer: Every type of security has a required amount of margin and margin maintenance set by Reg T (options, stocks, ETFs, leveraged ETFs, futures) and it varies by security type.  Brokers have the right to require more.
Comment: I traded some futures 30+ years ago but found that it wasn't for me so my experience is limited.  For reduced risk, I think that you either have to go with options (which you indicated that you don't want) or perhaps pairs trading where one side hedges the other, the margin requirement is less,  and you're trading the spread b/t the two contracts.
Comment: when I buy stocks, stocks etfs or sell covered options I don't need margin or maintenance unlike futures, forex, shorting stocks, naked options. commodity etfs are similar to which?, The second part is that I can hold stocks and stocks etfs for ever, while there is an expiry date for futures and options.. commodoties etfs are similar to which?


How do writers feel about translations of their works? Looking for examples

Question: I'm looking for examples of bilingual (or trilingual, etc) writers who actually read foreign translations of their works and comment on them. I'm curious to know how they feel. Are they generally satisfied with these translations? Do they feel uncomfortable about other people "messing" with their creations? Any common mistakes that they point out? I want to know their side of the story.
Comment: It's a good question, but it's too opinion based for SE. I suggest trying reddit.
Comment: Hi @kuchitsu, I find your question very interesting, but it is a bit too broad or opinion-based by the standards of the community, and it risks to be closed. Are you able to make it more specific? Maybe just focusing on one aspect of the perception of a translated work?
Comment: I'm voting to close this question as off-topic because it is not about writing technique. It probably belongs on Literature if anywhere.
Answer: An artical about Murakami: https://www.newyorker.com/books/page-turner/lost-in-translation
excerpt: ...Jay Rubin, one of Murakami's longtime translators, told me in Tokyo last month, explaining what he says to American readers, most of whom prefer to believe otherwise. "Murakami wrote the names and locations, but the English words are mine." Murakami once told me that he never reads his books in translation because he doesn't need to. While he can speak and read English with great sensitivity, reading his own work in another language could be disappointing—or worse. "My books exist in their original Japanese. That's what's most important, because that's how I wrote them."...
Answer: Milan Kundera is a Czech author, who has lived in France since 1975. He wrote his first novels in Czech, but he switched to French after going to exile in 1975 after Soviet invasion to Czechoslovakia. He was stripped of Czechoslovak citizenship in 1979 by the Czechoslovak communist regime.
He can speak Czech, of course. That is why he rarely allows his French novels to be translated to Czech by Czech translators; his opinion is he can translate his own work better than any translator. Czech readers must wait for the translation many years longer than the rest of the world.


how can i get file from smb file server at my app iOS

Question: I am developing an app,I want to get file from shared folder,I used bonjour to find file server around me and I get the ip address and server type;
now I want to get the shared file from these file server?how can I get these? I google it and I know to get this file I have to implement something like afp or smb ,then I can get file.
but can somebody tell me exactly what should I do? and can somebody give me demo? I searched a smb demo "tango" at github,but its doesn't work.
Answer: Just to be clear, 'bonjour', 'mDNS' or whatever else you want to call it assists purely with discovery, which you can do easily enough in iOS / OS X, assuming the SMB server you want is advertising itself as a service of type <code>_smb._.tcp.</code>. See NSNetServiceBrowser and related classes on how to do that.
The hard bit, AFAIK, is actually connecting to said server and retrieving the file. The best resource I can point to is this question here, and perhaps this client library (although I've never used it personally).
Hope this helps.


User ID is incorrect in sharepoint designer

Question: The users account id is "bethg", and her sharepoint profile reflects this. In sharepoint designer, however, when I search for her full name the id shows as "elizabethg" and the workflow bombs. Get-spuser does not pull "elizabethg" either so there is nothing to remove. Where is SP designer pulling this info?
Comment: I would bet the original name for the user was setup as "elizabethg" and later reset to "bethg". Like if you put in a List Name and later change it, the original list name stays the say, but displays differently to the user/developer. Is there anyway to use a UID instead of the account ID? The number with the UID should not change. I'm not sure on any of this, so just leaving it as a comment.
Comment: what SP version (2010/2013) and edition (std/ent) are you using?
Answer: I was able to fix this by typing in domain\bethg in SP designer user lookup. After I hit enter and went back in to do a look up, hovering over her name showed the correct user ID. Workflows are finishing successfully.
the environment is SP server 2010.
Thanks for the help!


how to analyze the difference in figures from year to year

Question: This is perhaps a basic question:  I have high school drop out data over a number of years.  There is a significant increase in the percentage of students that dropped out from 2015 to 2016.  I want to be able to explain the increase: was it girls, was it boys, was it school A, school B, etc.  I could calculate the percentage change for each variable, but is there some other way to analyze this?
Answer: It depends on the data you have available
If you have micro data, i.e. records of individuals, you might want to look into multiple logistic regression, i.e. modelling the probability of dropping out based on various explanatory variables, e.g. gender. It will also allow you to assess if the effect has changed over time.
If you have aggregated data, i.e. tabular data, you might want to look into chi-sqaure test, e.g. to see if there is any differences between drop outs based on gender.
Comment: Many thanks for this.  I have micro data.  For multiple logistic regression, do I train a model with 2015 data and then make predictions for 2016?  Where the predicted outcome is far from the actual outcome would be where my problem areas are?
Comment: Unless there is a good reasons not to do so (e.g. formal requirements in an assignment), I would fit a standard logistic model to all data and base my inference on the parameter estimates...


What is the use for the "realtime" priority for a process?

Question: In my experience, setting any process to realtime will make your computer slow down to a snails pace. What is the use of this setting, if it makes your computer unuseable?
Comment: If you have a multi-core processor or a multi-processor system, you can set affinity for only one core. That way, the rest of the system will remain responsive and you can enjoy the rest of the benefits of a real-time process. This of course only works well for processes that only need one core to work.
Answer: Exactly what you describe, at the cost of slowing the rest of your computer down to a crawl it runs the process in real-time giving it a higher priority than everything else. This is only necessary for time-critical applications, most people don't see these in their daily life...
Comment: Other examples of real-time apps are medical apps and directly controlled robotics. Things where 10µs is the difference between correct operation and failure (where failure may involve some robot driving off a cliff or a patient being exposed to too much radiation).
Comment: Some very common programs, such as sound servers (PulseAudio and JACK as two Linux examples), use real-time priority threads.
Comment: @grawity: JACK is not a server, but just a development kit. Both are cross-platform. Good point though that audio stuff requires real-time priority, but I was talking from a Windows 7 viewpoint where these processes you specify don't get real-time priority. Windows has something called the Multimedia Class Scheduler for these kind of processes though...
Comment: What is `jackd`, then, if not a sound server? (From what I understand so far, both PA and JACK work the same way in that they provide both a sound server and a library/kit to access it...)
Comment: That doesn't make the kit suddenly become a server. We're talking about processes here, not threads...
Answer: This may seem unnecessary but when a process is started, parameters can be passed that set the process to run at various levels of priority.  The Task Manager shows this as an optional setting because it is an option that can be set for the process by the software that initiated it's execution.  Most software runs under a "Normal" level, but occasionally you may see a few that are running at a lower level by default.  I've never seen software that starts in an above normal state.
It is also worth mentioning that there is a case when a process can run at the highest priority setting and it not seem to greatly affect your system performance.  For instance, if a process is started and it is assigned to work on only 1 of, say, 8 CPU cores, setting the processes priority to "real time" would mean that it would consume one processor, leaving 7 to be used by the OS and any other software.  In this case, real time execution could have almost no affect on the system but give a reasonable performance bump to the high priority process.
I would almost never recommend manually setting a process to run in "real time" from within the System Manager.  This is because you are changing the execution settings for a process that may have been designed to operate under one specific execution state.  Changing the execution priority can, in some cases, crash the application and if it's a data-write operation, possibly corrupt your data!
However, there are some cases where using a maximum execution priority setting for a process can be the right thing to do, but even then, such priority settings should be set by the controlling application and not by the end user through a system management dialog.
I, personally, would recommend NEVER changing a tasks priority unless you really don't care if it crashes and the task is COMPLETELY non-critical.  If software documentation explicitly states that you can elevate the process to run at a faster speed in order to expedite a very large load of processor work, then that would be acceptable as well, however, I'd be a bit skeptical if a mechanism from within the application is not provided.
As a personal anecdote, there is only one process that I occasionally change manually-- software compression applications.  I haven't had to unzip a massive file in a long time, but I have found that if I am in rush (ahem being impatient) I can crank up the process priority and get a moderate bump in performance.  Since these applications start a work task, and then close when they are finished, I don't have to worry about unsetting my processor settings because when the application is finished extracting the data, it will stop on it's own.  This is the only time that I have found it personally useful to control the processor speed through system management.
Comment: As a programmer I can't possibly think of a situation where giving a program more resources would crash it
Comment: As a programmer, yes, but setting a process to run at a specific level can cause issue, especially if the software was written (possibly even poorly) to run concurrently with other processes.  My suggestions come from both experience and with an understanding that not all users are developers.  Setting priorities of processes that are running, that you have not developed can certainly elicit unexpected behavior.  I don't want to scare any one, however, I also don't want to encourage other users to mess with process settings *if* there is a chance that their changes could be damaging.
Answer: I use the Real Time priority to speed up games on my non-gaming laptop.  I don't care about the background process when I am in game and I get a much more enjoyable experience out of allocating my processing power this way.


Using other glyphs in Arabic on the iPad

Question: Arabic Keyboard on iPad uses GeezaPro font and obviously keys are limited compared to available glyphs, but what should I do if I want to use a glyph that doesn't have its own key. Is there any way I can add/use it somehow?  The reason I need to do this is so I can write in Persian/Farsi.
Comment: Please explain what glyph exactly it is you want to make, since the keys are normally sufficient to make everything standard arabic requires, even if it seems at first glance like they are limited.
Answer: If you search the app store for "persian" you should find a few keyboard apps which will make the characters you are missing and which may be useful for email and some other purposes.
Answer: You may be able to access what you want by using Character Viewer (Edit > Special Characters).  It would help to know exactly what it is you think cannot be made from the keyboard.
Comment: This question is asking about glyphs on the iPad, where there is no Edit menu
Comment: Yes, I was not paying attention.  The correct answer is to use Unicode Maps or a similar app as suggested by Jonathan VM.  Although I would still like to hear why additional glyphs are believed needed, as that is not at all obvious.
Answer: As far as I know, not with the "soft" onscreen keyboard. Unfortunately the Arabic keyboard doesn't have the "tap and hold for more glyphs" feature that some of the other keyboards support.
But there is support for 3 different hardware keyboard layouts (Arabic, Arabic PC, Arabic QWERTY), so perhaps with an external Bluetooth keyboard you could gain access to more glyphs.
Another alternative would be to use a 3rd-party app like Unikey or Unicode Maps that gives you access to a full range of Unicode glyphs and lets you build a custom keyboard. Not as elegant and usable as having what you need built in to the OS, but it could be a stopgap solution until Apple further improves their Arabic support.
Make sure to submit feedback to Apple to let them know your language needs better support!
Comment: The Arabic keyboard Does in fact have several keys which you can tap and hold get more glyphs, such as ا ه ز ك ل ب ف ج ً
Comment: Ah, I stand corrected. Doesn't materially change the rest of my answer but might be good for the original poster to know if they haven't already found those.  Good correction!
Comment: Yes I already know about that tap-and-hold, but I'm talking about the other hundreds of keys available in the Geeza Pro font, or any other font for that matter -- any way to access this on iPad?
Comment: As I said, not with the software keyboard, but you can try a Bluetooth keyboard, or one of the apps Unikey or Unicode Maps.
Comment: @Nimbuz  I am still puzzled why you think this is necessary.  Could you give an example of something in Geeza Pro that you think you have to input but cannot?
Comment: Some persian chars that are not available in arabic, but present as a glyph in the geeza font
Comment: @numbuz  Have you already tried the Persian/Farsi keyboard apps in the app store?
Answer: Yes, there is! Here's how:
First find the character/glyph you want to enter on the Char Map or online or whatever way you prefer.
Then go to iPad Settings > General > Keyboards > Text Replacementand tap the + button on the top corner. Now paste the glyph in the Phrase field, and enter the desired keyboard shortcut for it. Then press Save.
This way whenever you want to enter that particular glyph, you can just type in your shortcut on your Arabic keyboard and it will replace it with your desired character.
For instance I used to use the Arabic ' ك' to input the Persian equivalent 'ک' when there was no Persian keyboard available in iOS. You can also use the same approach to input longer phrases when typing a specific shortcut.


Getting Decoding Error with Accented, Latin Characters Magento 2.2

Question: I'm trying to create products via the REST API but in the body of the request I send accented characters (á, é, ñ, etc) and I get a decoding error as a response, I have configured postman to send the request with UTF-8 encoding, but I still get that error, apache is also set with UTF-8 encoding as well.
Thanks in advance for any help.
Answer: I have the same issue.
Workaround is to decode product names before sending to Rest API:
<code>var product_name_encoded = product_name.replace(/[\u00A0-\u9999<>\&]/g, function(i) {
  return '&#'+i.charCodeAt(0)+';';
});
</code>