Why dissolve creates many extra features?

Question: I have a shp file in Arcmap 10 that has ~16600 polygons. Some overlap. I want any polygons that are overlapping to be dissolved into single polygons. I want non-overlapping polygons to remain the same. When I use Dissolve as suggested here How to dissolve overlapping polygons? I get about 93000 polygons. Why is it touching my non-overlapping polygons? Only thing I can guess is that it's something to do with polygons that were multipart polygons to begin with and now I've unchecked "create multipart polygons." If that's it, how can I work around that? If not, what gives?
Comment: Would it be possible to include pictures of some polygons that are not being processed in the way you desire, please?  Not 10,000s of polygons - just 2-3 of your simplest ones - or some mocked up circles/squares. I suspect preparing such examples may lead you to answer your own question.
Comment: Images are added using the image icon in the editor (rightmost box in the second icon group from the left). Have you tried *checking* "Create multipart polygons"?  You can't have it both ways, since splitting multiparts is the first step when that checkbox is deselected.
Comment: Thanks. The issue is the creation of many single features polygons from the many original multipart polygons that never had any overlap. Not sure how to add an image from my hdd, but not sure it would help to see dissolved and non-dissolved polygons.
Is there are way to tell arcmap not to separate the multipart polygons that are not being dissolved?
Comment: Could you please edit your question to describe what, if any, attributes your polygons might have and whether they need to be preserved or updated? Various answers given might affect them in different ways. I think everyone has a part of the answer but it's not been put together yet. Poly count increases because your multiparts are split when you don't allow multiparts with Dissolve (Vince). A solution is to run dissolve on *only* overlapping parts, but some increase is possible if *part* of multiparts are overlapped (answers). Not clear on what you need, but Merge may also work.
Answer: If you don't mind a few extra geoprocessing steps, I would suggest a workaround. Before dissolving, perform the following steps. Select all features in your shapefile. This is easy to do with the 'switch selection' button in the shapefile's attribute table. Then perform a select by location, with the shapefile as both the input and the selection feature. For 'selection method', choose select from the currently selected features in. For spatial selection method, choose are crossed by the outline of the source layer feature. Perform your selection and overlapping features in your shapefile will be selected. Now you can perform your dissolve on your shapefile, and the tool will only geoprocess what is selected. Finally, switch your selection on your original shapefile, and merge it with your dissolve output.
If it's not an ArcGIS bug and you do instead have multipart polygons that you do not want, first use the multipart to singlepart tool on your shapefile before dissolving.
Comment: This does not work as described.  If you have only one layer in a map the Select by Location will not allow you to use that layer as both the target and the source.  If you add the same data to the map twice to create two separate layers, than selecting one against the other just selected everything in the layer.  So your description is missing a step that isolated the intersected parts.  I believe my answer deals with that missing step by using the actual Intersect tool on the one feature class to make the features that can perform the selection using a small negative buffer.
Comment: @RichardFairhurst There is a `Select *Layer* by Location` GP tool that will allow the same layer to be used as both target and source. Intersect still won't work, since all shapes will intersect themselves, but 'crossed by the outline of' should do the trick. In fact, that would also work with the regular Select by Location if you add the layer twice.
Comment: Using the Select Layer by Location GP tool is not indicated in the original answer and the reference appears to be the Desktop Select by Location tool, nor does it mention the 'crossed by the outline of' option with duplicated layers.  Either way it is missing a step as I pointed out.  The Intersect option won't work as you mentioned.  The Intersect tool however does work.  You only include the layer once, not twice, and only overlapping portions are outputted.  Self intersects do not happen when only one layer is used as an input as both my answer and FelixP's answer correctly point out.
Comment: @RichardFairhurst Sorry for any miscommunication. Your original comment is correct, as described the solution given does not work. I was only pointing out corrections that could make it a valid answer (without the creation of additional layers/buffers), addressing the flaws you pointed out. As far as Intersect, I was referring to the *method* of Select by Location in terms of "won't work" - *not* that the Intersect *tool*, an altogether different solution, wouldn't work.
Comment: Chris:  It took me a couple of reading to realize you were referring to the Intersect option of the Select by Location or Select Layer by Location tools and not the Intersect tool, but I got it eventually.  I also agree that with your modifications that the approach of the original answer could be made to work.  I never understood what the 'crossed by the outline of' option did, so I appreciate the insight into how to apply it to this situation.
Comment: @RichardFairhurst Some of my comment formatting relates to notifications. Any original poster is notified if a comment is made. If there is only one commenter, they will be notified if OP or the first other person also comments. After that (more than one commenter), notification can only be given with @ username, limited to one per post. So my first comment notified you *and* Emil so he could revise his answer if he wants. Your follow-ups have not notified me, I came looking. :) This may be helpful on methods: http://resources.arcgis.com/en/help/main/10.1/index.html#//00s50000002q000000
Comment: Thanks for the comments. Clearly I was wrong on how to select overlapping features. I've updated my answer.
Comment: Your revised answer still doesn't address that you cannot use the same layer as both source and target with the regular Select by Location tool - doesn't matter if anything is selected or not, the dialog will not let you use the same layer in both places. You must either use the Select Layer by Location tool or have the layer added twice to use the regular Select by Location.
Comment: Hmm, works for me. Maybe it's a 10.1 thing? That's my version. Image:  https://drive.google.com/file/d/0B9n9YNu8ulsmajVKNktFOFZzaTQ/view?usp=sharing
Comment: I stand corrected. As long as you already have features in that layer selected, it *does* appear in the Source choices, but *only* if you have a selection active. Verified in 10.2. And on further reflection this makes sense and I'm not sure what I was thinking - I've used it before to 'grow' selections (ie, select those touching the boundary of selected in the same layer).
Answer: If you mean to keep the attributes meaningful, it makes no sense to dissolve the overlapping polygons if you care about those attributes.  Since it appears that dissolve has already occurred, then if your problem is sliver polygons, you should perform an Intersect on the one feature class and then select every polygon in the original that overlaps a small negative buffer on the Intersected features followed by use of the Integrate tool on the original (make a backup first).
If the overlap is more than slivers, show us a picture of these overlaps and explain what attributes you want over those you don't.  On the other hand, if you were willing to sacrifice all attributes as suggested in the post you were following, who cares if it is one huge multi-part polygon in the end.  All parts of the shape mean the same thing as any other part once you sacrifice the attributes.
If on the other hand you in reality want some attributes to dominate over others, that is a different story, and you then should not let touching polygons that don't overlap be combined in a Dissolve if they have distinct attributes (which the original method you were following would destroy).
Answer: Use intersect tool with single input, call result OVERLAPS. Select original that intersect OVERLAPS and dissolve originals. Switch selection in originals and merge with dissolved.


How can I find "hidden" colors in an Illustrator document?

Question: I made a color group of black and white objects. But it shows 3 different blacks and 1 gray and 1 white color in the swatch.
How can I isolate or find/see those specific colours that are unwanted in my document? Or how can I delete/remove a specific color from an object? If the color is not to be seen?
Answer: With nothing selected in the artwork....

Highlight a swatch in the Swatch Panel
Choose Select > Same > Fill Color from the menu
The objects using that swatch for that fill color will become selected
Merely click the swatch you want to use to replace that color
Do the same again, de-select all, click the bad swatch... but this time choose Select > Same > Stroke Color to find strokes using that swatch

Note I suggest using Fill Color and then Stroke Color rather than Fill & Stroke Color because this will better target the color use. If you have objects with varying fills, but the same stroke color, Fill & Stroke Color won't pick up those objects. By specifically targeting the fill color, then the stroke color, you ensure you get all uses of that swatch color.
Answer: In addition to Scott's answer:
We can change the colors using the Recolor Artwork panel.
This will change the fill and stroke at the same time.


If PRF is non invertible, why does Ctr-mode work?

Question: I am currently taking Dan Boneh's Cryptography I course online.
I have just finished the segment discussing the Cipher Block Chaining and Counter-Mode.
I am having difficulty understanding why Ctr-Mode works as an encryption algorithm as PRFs are fundamentally non invertible, as per my understanding. Any clarification on this would be highly appreciated!
Comment: @RickyDemer I've generated an answer without (too much) math in it, but I would happily vote up an answer that explains the mathematics behind it.
Comment: For any length, $\: \langle$ binary_strings_of_that_length , xor $\rangle \:$ is an [abelian group](https://en.wikipedia.org/wiki/Abelian_group#Definition). $\hspace{1.92 in}$ For any length, each element of that group is its own inverse. $\;\;\;$
Answer: CTR consists of two parts: construction the key stream using a counter, and XOR-ing the output of the key stream with the plaintext/ciphertext. The key stream can be generated using a PRF, in which case it is of course not invertible. The key stream can also be created using a PRP (e.g. a block cipher like AES) in which case it is invertible.
As indicated, CTR mode encryption requires the XOR-ing of the plaintext / ciphertext as well. A PRF is a pseudo random function, so given the same input it will generate the same key stream. The XOR-ing of the key stream is perfectly reversible; you just have to perform the XOR with the key stream again. So CTR mode encryption is always reversible, even when it relies on a PRF to generate the key stream.
Because of this, CTR-mode is indeed not a PRF.


How can I run an application with arguments from Windows Explorer?

Question: Is there an easy way to launch an application from Windows Explorer with arguments?  Or do I have to actually run them from the command line?
Comment: Are you limited to command line or launching from Explorer? Would a simple batch file or shortcut work?
Answer: If you open any folder, then the shortest way to run any application with arguments is just typing program name and arguments in the upper textbox.

Otherwise, if your program is on Desktop, you can use various ways such as:

Click on any folder on your desktop, up one level, and do the same as is in picture.
Press Win+R, write cmd.exe /k cd desktop, hit enter, write
program name and arguments.
Create a shortcut or a batch file with this command:
cmd.exe /k cd %systemdrive%\%username%\desktop
run it and write program name and arguments.
Answer: It sounds like you want a brief script that you can just double-click to run a command with certain arguments - is that right? If it is, here's one way:
Open a simple text editor, like Notepad, and type in the commands with the arguments you want it to take, like so:
cd %USERPROFILE%\useful-files\executables
putty.exe 192.168.2.10

(In this example, putty.exe is a program that can take IP addresses as arguments, and it's saved in C:\Users\\useful-files\executables.) When you're done, save it with the .bat extension (if you're using Notepad, just make sure you replace the .txt it starts you off with; in our example, we could save it as something like run-putty-with-IP.bat).
If you've done this correctly, in File Explorer it will show the file type as "Windows Batch File" and double-clicking it will run its contents.
Note that certain programs, without configuring system or environment variables, will require you to change to their directory to be able to execute them, hence the cd command included here.
Comment: Thanks. This is a good answer, but I was really looking for some way of doing this in Windows Explorer without having to create another file.
Comment: how to quit the command window (started by the bat) afterwards ?
Comment: Use `start` as here: https://superuser.com/a/192572/185071
Answer: Foggy memory here, but I believe there was a TweakUI addition to the Windows XP context menu for CMD and BAT files that allowed you to add your arguments and run the script. I believe this is what OP is looking for, and I would also find that very useful.
--tim
Comment: Hold `shift` then right-click on the `.bat` file. Choose "Copy as path." Press `WinKey`+`R` to open the run dialog. Paste into run box with `Ctrl`+`V`. Add a space and type your arguments. Press `enter` to run. It's not as complicated as it sounds, and getting used to using "Copy as path" is a good thing, as it can be useful for a wide variety of tasks.
Comment: Another trick you can use is to open a cmd.exe window and drag the batch file onto the cmd.exe window, where it will paste the full path to the batch file into the command line. You can then type in whatever arguments. This also works for creating arguments. E.g. type `dir ` (with a space after it) in cmd.exe, then drag a folder onto the cmd window and press enter. Or drag a .bat file to the window, press space, then drag a target file to the window. e.g. jpgrotate.bat my.jpg can be achieved by drag'n'drop into cmd.


SQLBUlkCopy to call StoredProcedure to insert or update data in SQLDb

Question: I am having a list of records which I need to insert or update in a SQL DB based on whether the record is present or not present in the database.
The current flow is I process each record 1 by 1 and then call a Stored Procedure from my C# code which does the task of inserting or updating the database.
The above process is very inefficient, Can i use SQL Bulk Copy to insert these in once into the SQLDb .
Will above increase the performance .
Regards
Ankur
Answer: SqlBulkCopy can only insert. If you need to upsert, you might want to SqlBulkCopy into a staging table (a separate table off to one side that isn't part of the main model), and then do the merge in TSQL. You might also want to think about concurrency (how many people can be using the staging table at once, etc).


France study & working

Question: I understand that with a long stay student visa in France, you can work 964 hours per year. Does that include working on a contract as an Independent Contractor? On that contract, I would be traveling to a number of countries on the European River ships. As long as I stay within the 90 day Schengen limitations in the other countries, is that ok?
Comment: https://www.service-public.fr/particuliers/vosdroits/F2713 mentions 'activité salariée'. I'm not sure that independent contractor fits into this category.
Answer: In France, all international students have the right to work, up to 964 hours a year. It starts with issuance of your student residence card or validation of VLS-TS (with some exceptions), by the Office of Immigration and Integration (OFII) within the first three months of arrival.
You can exercise any paid activity without a work permit. However, the employer has to declare your name to either the prefecture of your residence (VLS-TS) or at the prefecture that granted your residence permit, and has to do this before you can start work.
Work as an independent contractor may not qualify and, in particular, if the employer/employment is not based in France and/or cannot demonstrate adherence to SMIC (Salaire Minimum Interprofessionnel de Croissance), including the mandatory taxation for France's social security benefits (20 percent deducted from the gross salary).
If you are not an EU national, your French student visa may allow you access to the Schengen area, but the French law that allows you to work doesn't extend to unlimited employment throughout the Area.
To avoid jeopardizing your status, it would be advisable to consult both your university's international student office and the OFII.

France study & working


Fix for "Incorrect Resource URL" message

Question: In my Wordpress installation of CiviCRM I have had a persisting System Status:Error message since version 4.7.28 which was still present despite upgrade to 4.7.31.  This appeared to be a false-positive as CiviCRM was working well.
The Resource URL was correct and I could not get rid of the error until I upgraded PHP from version 5.6 to version 7.0, and the error message disappeared!!
Answer: The error disappeared after upgrading php to version 7.0


Can a parish change boroughs?

Question: In light of the recent Brexit vote, I was curious as to whether parish councils could also call for something similar, with governing borough councils if they were seen to be negligent of said parish. For example could a parish council legally either trigger some legislation to move to another borough (or even become an independent district), or would this require a referendum of sorts, if at all possible.
Comment: @Thomo You have to understand that the Common Law of England long pre-dates the Reformation, the Parliamentary Wars of the 1640s, the Glorious Revolution and Bill of Rights of 1688, and the Great Reform Act of 1832. There was a time when there was no distinction between the ecclesiastical and the secular and Parishes date from then. They are the oldest units of government in Britain. But nowadays they are entirely separate from the Church.
Comment: Possibly related: [procedure for boundary changes](http://webarchive.nationalarchives.gov.uk/20160105160709/http://www.ons.gov.uk/ons/guide-method/geography/beginner-s-guide/administrative/our-changing-geography/boundary-changes/index.html); and [this page](https://consultation.lgbce.org.uk/faq) mentions that parish boundaries can be changed by the district council.
Comment: Could you provide some more context or definitions for those of us not familiar with your terms and usage? When I read Parish, I automatically think Church - which begs the question of what this would have to do with local governments...
Comment: @WS2 which is exactly why I asked for a clarification and/or definition for the those particular terms and usage, which Brythan kindly linked to with his edit. What with this being an international forum, to avoid confusion then those definitions should be given because those terms can mean different things to different people
Comment: @Thomo - this is clear that it is UK so the definitions are clear. If you get a US question do you want definitions of states as they are entities that are not common to most people?
Comment: Wow, if half the effort went into actually answering the question as it has into attacking someone because they've asked for a definition to be inluded...
Comment: @Mark yes, actually, I  would. Because it's relevant to the question and provides context
Comment: So **every** question should include the basic information of the country's sub parts?
Comment: For what it's worth, I read "parish" and think of [Louisiana](https://en.wikipedia.org/wiki/List_of_parishes_in_Louisiana), not the UK or the church.
Answer: With the caveat that I do not believe any parish council has declared independence so the legal situation hasn't been tested, I believe the answer is as follows:
There is no legal basis for which a parish, borough, county or district can claim independence. That doesn't, however, mean that the law couldn't be changed to allow it.
On a larger scale, it is fundamentally no different to the situation with Scotland and the call for independence there. Currently, the law does not allow for Scotland to become independent, unilaterally, even though it has its own government. For it to become a properly independent nation, the Westminster parliament would have to enact the relevant legislation.
Brexit is somewhat different because there is an explicit mechanism for a nation to leave the EU: the now famous Article 50. Even there, the wording is commonly assumed to require an act of Parliament to invoke although this is by no means a universal interpretation.
One last point of clarification. In neither the Scottish nor EU independence cases was a referendum sufficient to actually invoke independence. In both cases it is legally, though probably not politically, possible for the government of the day to set the referendum result aside. So, unfortunately, the parish council independence referendum wouldn't be sufficient to  declare the Independent Republic of Upper Hazelfordmere. Mores the pity.
Comment: Of course describing Scotland as having its own government gets complicated as well, given that from Westminster's point of view it's just another body to which parliament has chosen to devolve some decision making powers on certain issues. But then, I guess that's actually your point.

Can a parish change boroughs?


Convert OpenType (PostScript flavor) to OpenType (TrueType flavor)

Question: I want to convert a OpenType (PostScript flavor) font to an OpenType (TrueType flavor) font. This is because Office Word cannot make pdf´s using a OpenType (PostScript flavor) font. To make it more difficult, I also want to maintain the openType typography tables.
Comment: What have you done so far in pursuit of this goal — a goal that may or may not turn out to be the jackalope of font-file esoterica? Also, do you have FontLab, and/or the wherewithall to install and subsequently do battle with the GUI of [http://fontforge.org](fontforge)? I ask so I know how to best answer; best of luck either way.
Answer: FontLab will do the trick. Hefty price tag for a one off job. Have you considered contacting the foundry you purchased from.
Answer: TransType is a software dedicated to this kind of conversions. They also have a per-day price, if you don't want to buy it.


What do you call people who are not good at explaining things?

Question: For example, some researchers have conducted great researches, but they may find it quite difficult to explain the methodology or background info to the audience.
Answer: It depends on the exact context, but I would probably call them "bad/poor communicators", though something more tactful would be required if I had to say this to their face. The polite method would be to emphasise that someone else was a "better communicator", or "better at public speaking".
Comment: Thank you! Actually, I want to tell my audience that I am not quite good at explaining my research design at the beginning of my presentation to lower their expectation. So would it be ok to say things like "I am a poor communicator/explainer, but I'll do my best to show you the way i am going to conduct my research and the methodology behind"?
Comment: Slight improvement would be to say "I'n not very good at explanations"  or maybe "I'm not very good at public speaking"  but ironically, if you use bad grammar at that point, you may well get them on your side a bit more than if you say it perfectly!
Comment: Thanks again!! I take your point, but I have to add that having a good command of a certain language only doesn't ensure the ability to explain complicated things very well in the language. Sometimes it takes more than knowledge of grammar or vocabulary to make our opinions clear to the audience.  Have a nice day,:-)


What must a Catholic believe to be a Catholic?

Question: What must a Catholic believe to be a Catholic? I know we must believe the articles in the Nicene and Apostolic Creeds and the Ex Cathedra statements about Holy Mary's Immaculate Conception and Assumption. What else must be believed, to be a practicing Catholic, according to the Catholic Church?
Comment: Just for clarity's sake, can you specify: 'must believe' for what?
Comment: I don't believe @anthony's question is a dupe, but the answer might be the same  https://christianity.stackexchange.com/a/81090/4
Comment: To be a Catholic
Answer: Truths absolutely necessary for salvation
The four truths absolutely necessary to believe for salvation are that

"he [God] is", i.e., that God exists (Heb. 11:6)
God "is a rewarder to them that seek him." (Heb. 11:6)
the Second Person of the Trinity took on a human nature (Incarnation)
God is Three Divine Persons in one God (Trinity)

Note: There is unanimous consent among Catholic theologians that truths #1 and #2 are absolutely necessary to be explicitly believed in order to be saved, but not all theologians (St. Thomas Aquinas, St. Alphonsus Liguori, et al. excepted) think that explicit belief in truths #3 and #4 is necessary; cf. True or False Pope p. 113 // PDF p. 128.source
Truths necessary to be Catholic
To be Catholic, one must, as the asker writes, indeed "believe the articles in the Nicene and Apostolic Creeds and the Ex Cathedra statements about Holy Mary's Immaculate Conception and Assumption" (cf. the 4 Marian dogmas).
Comment: Can children be Catholics without believing those things?
Comment: What about the four Marian dogmas?  https://www.catholicnewsagency.com/resources/mary/general-information/the-four-marian-dogmas
Comment: Thank you so much -- especially for summarizing the document!
Answer: What must a Catholic believe?
Even though only two doctrines have been declared ex cathedra, there are many others that the church professes must be believed. Some of these are laid out in the 1998 Commentary on the Concluding Formula of the Professio fidei issued by then-Cardinal Joseph Ratzinger of the Congregation for the Doctrine of the Faith.
According to this document, many teachings are "irreformable" and "definitive" and as such can be seen as possessing the binding quality of an infallible doctrine, although not necessarily proclaimed ex cathedra. That is, they aren't promulgated by the pope himself but by the larger magisterium of the church. The lineup of "irreformable" teachings—ones divinely revealed—include those regarding Jesus, Mary, sin and grace, the sacraments, the primacy of the pope, and the doctrinal formulations of the ancient creeds.
Thus the points of the Catholic faith are to be blindingly professed by all Catholics and must be believed in are as follows:

Apostles Creed
Nicene Creed
Second Person of the Trinity took on a human nature (Council of Chalcedon)
Seven Sacraments
Primacy of the Pope
Divine Motherhood of the Virgin Mary
Perpetual Virginity of Mary the Mother of Jesus
The Immaculate Conception
The Assumption of the Virgin Mary

These points of profession are to be held as dogmatic truths by all Catholics in order to remain in the complete fullness of the Catholic faith.
There is some talk as to where Pope John Paul II wrote his Apostolic Letter Ordinatio Sacerdotalis in an ex cathedra manner. Some theologians do not think so, as the term infallible was not mentioned in the document but it must be noted that the infallible appears nowhere in any of the other infallible teaching documents either. Nevertheless it was strongly worded.
When Pope John Paul II said in Ordinatio Sacerdotalis that the church lacks the authority to ordain women, the word infallible did not appear. But the pontiff did say that this teaching should be "definitively held" and suggested that further debate was pointless. But on the issue of mandatory celibacy for clergy, Archbishop Pietro Parolin, the new papal secretary of state, noted recently that this is a matter of church discipline and not dogma, that the early church had married priests and that the matter of priestly celibacy is therefore open to discussion.

Although the teaching that priestly ordination is to be reserved to men alone has been preserved by the constant and universal Tradition of the Church and firmly taught by the Magisterium in its more recent documents, at the present time in some places it is nonetheless considered still open to debate, or the Church's judgment that women are not to be admitted to ordination is considered to have a merely disciplinary force.

Wherefore, in order that all doubt may be removed regarding a matter of great importance, a matter which pertains to the Church's divine constitution itself, in virtue of my ministry of confirming the brethren (cf. Lk 22:32) I declare that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church's faithful. - Ordinatio Sacerdotalis

The Church also acknowledges that some individuals may be incapable of making a proper profession of faith such as babies, small children and people with developmental disabilities, but that does not make them less Catholic! Intellectual impediments have always existed in the history of mankind and will always continue to be as such. We live in a world with a damaged human nature.

What Catholics Must Believe – Dogma, Doctrine or Discipline?
In this post I'll explore what is meant by a Dogma, a Doctrine and a Discipline. I'll explain where these terms derive from and how they form our faith. Finally to get specific, I'll present a list of the 258 Dogmas of the Catholic Church (that I could find) that all the faithful must believe.
Simple Catholic Truth
In the previous post entitled "What Does It Mean To Be Catholic?", I concluded that there existed a set of core beliefs that all Catholics must believe in order to be considered Catholic. For lack of time and space, I deferred a more detailed examination of what these beliefs are and where they came from until now. I will also include a final (optional) element of the Church's faith teachings which are called Disciplines.
Taken together, Dogmas, Doctrines and Disciplines compose the framework of teachings of the Catholic Church. In sequence, Dogmas, Doctrines and Disciplines form a sort of descending classification of Catholic Christian truths. As we descend down this taxonomy, the relative importance and certainty of the teaching(s) decreases. For example, at the top of the list (Dogmas) we have absolute theological truths directly revealed to mankind by God. At the bottom (Disciplines) we have theological projections or opinions or practices that are useful, but otherwise can still be open to debate and change.
Dogmas:
A Dogma is a truth revealed by God.  Because they are revealed by God, Dogmas are essential elements of our faith and can not change. Dogmas are formally taught to us by the Church and as such are taught (infallibly) without error.
These Dogmas require the fullest and complete assent of theological faith by all members of the Catholic Church. In other (SCT) words, to be considered Catholic we must hold these to be true "beyond all doubt."
The deliberate and obstinate denial of a Dogma of the faith is called heresy because this person rejects the revealed Word of God.
Examples of Dogmas: Divinity of Christ, Immaculate Conception, Real Presence of the Eucharist, Assumption of the Blessed Virgin Mary, Papal Infallibility.
Doctrines:
Doctrines are also infallible teachings of the Church on matters of faith and morals but are not directly revealed by Christ. Doctrines are true but have been defined by Biblical, historical or logical extension of, or connection to, Dogmas.  Doctrines can develop over time as the Church comes to understand them better—but Doctrines cannot change. No one—not even the Pope—has the authority to change Doctrine.
Every believer is therefore required to give "firm and definitive assent" to these doctrinal truths. In other (SCT) words, to be considered Catholic we must hold these to be true "beyond a reasonable doubt."
Whoever rejects a Doctrine rejects the idea of the promise of Jesus and the power of the Holy Spirit to protect the teaching authority of the Church.
Examples of Doctrines: Resurrection, The Incarnation, Heaven, Holy Trinity, Priesthood reserved for males.
Comment: "Most theologians do not think so, as the term infallible was not mentioned in the document" It must be noted that 'this is an infallible teaching' appears nowhere in any infallible teaching document.
Comment: "church professes must be believed" Must be believed in order to what?
Comment: This answer is fundamentally incorrect.  Most Catholics do not believe things like the assumption of Mary.  They have no idea what it means, they have no idea that the Church teaches it, and they have no idea that it is a dogma.  Nevertheless, they are Catholics in good standing.
Comment: @zippy2006 You can post an answer if you wish? **"Most Catholics do not believe things like the assumption of Mary."** Your sources please! The *Apostolic Constitution of Pope Pius XII **Munificentissiimus Deus*** as  a [Papal Constitution](https://www.newadvent.org/cathen/04321a.htm) is binding to all Catholics! That said, you can expect that many self-identified Catholics and "Catholic" groups don't believe the doctrine. But, by virtue of the Papal Constitution, they're not "formally recognized by" or "in full communion with" the Catholic Church.
Answer: Membership in the Catholic Church
In Joseph Ratzinger's 1986 article, "The Ecclesiology of The Second Vatican Council," he says:

A first important point was the dispute about membership in the Church
which resulted following the encyclical on the mystical body of Christ
which Pius XII had published on 29 June 1943. He had declared at that
time that membership in the Church is tied to three presuppositions:
Baptism, right faith, and affiliation with the legal unity of the
Church.

That is, in order to belong to the Catholic Church one must be baptized, one must have right faith, and one must recognize the Roman Pontiff, bishops, etc.  See Mystici Corporis Christi, #22 and #69.

"Right faith" and a note regarding positive beliefs
There is a strained assumption in the question, "What must be believed?"  The Profession of Faith certainly includes the ancient creeds, but an answer like Ken's is fundamentally incorrect when it lists off a number of dogmas and doctrines as checkboxes that must be filled in.  To take one example, the assumption of Mary does not need to be positively believed by someone in order for them to belong to the Catholic Church.  Actually, most Catholics are unaware of this dogma and do not believe it.
As the Profession of Faith makes clear, what is required by "right faith" is not positive belief in dozens of doctrines, but rather assent to the Church and what She teaches.  After the creeds, we are assenting to the Church.  Membership does not require us to know, memorize, or recite all of the various dogmas and doctrines.  It requires us to recognize the Church as authentic teacher.  Someone who assents to the Church but is not aware of a particular dogma is still a Catholic, for if they discover that the Church teaches something, then they will believe it.
Comment: In St. Thomas's day, the Assumption had not been defined. It is now. On 1 November 1950, invoking his dogmatic authority, Pope Pius XII defined the dogma: **By the authority of our Lord Jesus Christ, of the Blessed Apostles Peter and Paul, and by our own authority, we pronounce, declare, and define it to be a divinely revealed dogma: that the Immaculate Mother of God, the ever Virgin Mary, having completed the course of her earthly life, was assumed body and soul into heavenly glory.**
Comment: Can you post a Church directive that states Catholics are free **not** to believe in the Assumption of Mary. Whether some of the faithful do not believe in certain issues, does not change Ecclesiastical truths. I doubt most Catholics are unaware of this dogma, as you claim.
Comment: I would recommend reading up on implicit faith vs explicit faith.  For example, [ST II.II.2.5](https://www.newadvent.org/summa/3002.htm#article5).
Comment: As usual, you seem unable to comprehend the answers given.  Catholics are not required to positively believe every single dogma that has been defined.  That is why the Profession of Faith does not list every doctrine of each of the three levels.  That is why no catechumen is quizzed on such things, or made to memorize such things.
Comment: St. Thomas died in the 13th century.  The dogma was defined in 1950.  It has not "been definitively defined since St. Thomas's day."  Goodbye, Ken.  I hope @Eva learns something.


Why do some Muslims have triangular green flags with frills at the edges on top of their houses?

Question: Why do some Muslims have green flags on top of their houses? A triangular flag with frills at the edges.  I have mostly seen these on those from sub continent. Is this a sunnah or a cultural practice?
Comment: Could it be the Pakistani flag?
Comment: No ... it is a triangular flag with frills at the edges.
Answer: Well, Shia Muslims Practice this. They usually use green or black flag on their houses. The reason is connected to the Tragedy of Kerbala.
We all know, in Kerbala 10th Moharram, 61 hijri, Imam Hussain, his whole family and companions were killed in desert. The person who was the flag bearer of Imam Hussain was his brother Moula Abbas Alamdar. Alamdar is arabic word means the flag bearer.
While on the tenth of Moharram, the whole family of prophet was thirsty from three days, the daughter of Imam Hussain, Bibi Sakina(5 years old) requested Moula Abbas to bring water from Furat. Moula Abbas after the permission of Imam Hussain went to bring some water. He was himself thirsty for three days, but he did not drink water until everyone else has drunk it. On the way back to tents, he was killed, and the water did not reach the tents.
Relating that Flag of Moula Abbas, Shia's place a flag on their houses to remember the great sacrifice on Ashora.
Green color is used because BANI HASHIM's clan color was Green, as arab clans had different colors for each clan. while black flag resembles the grief.
Comment: It is also called Alam e Abbas, Alam means flag


"Go on, I dare you!" - Does a similar phrase or concept exist in German?

Question: My brother in law and I were having a discussion around 'dare' vs. 'etw. wagen'. I had said something along the lines of "ich wage dich etw. zu machen" and he intimated that it doesn't really work in German. Is there a viable alternative?
Comment: "traust di nie!" (in Austria) from "sich (ge)trauen"
Comment: https://www.linguee.com/english-german/search?source=auto&query=i+dare+you
Answer: You could say something like "komm schon, trau dich".
Comment: Could you please elaborate your answer a little bit. It is correct, but it is a little bit short...
Comment: What would help is a literal translation, along with an explanation of why it means the same thing.
Answer: Your brother is right - "to dare" has (at least) two different translations in German that each cannot be replaced by the other:
"Ich wage etwas (zu tun)" only works if I, the subject, am the one who is challenged to do something, i.e. "I dare to do something".
On the other hand, if I say "I dare you to do something", the challenge goes to you, the object. In this case, the correct translation is "Ich fordere dich heraus, etwas zu tun".
("Ich wage dich, etwas zu tun" is plain wrong and "Ich fordere heraus, etwas zu tun" is a bit weird and has a completely different meaning anyways)
It's surely possible to translate "Go on, I dare you" very literally by "Mach weiter, ich fordere dich dazu heraus", and this would be a correct German sentence. However, it does sound very unnatural (it doesn't really capture the threatening undertone of the English counterpart).
Laurin's "[Komm schon / Na los], trau dich (doch)!" (~"Come on, dare to do it!") is a much closer alternative.
Answer: In addition to the other answers I also know the phrase Mach nur so weiter (du wirst schon sehen, was Du davon hast)... as a threat for consequences if you actually dare to go on.
Answer: The German word wagen is no complete equivalent of to dare. Merriam-Webster lists several meanings. Not all can be translated by means of wagen:

(auxiliary verb) to be sufficiently courageous to

"no one dared say a word": "niemand wagte es ein Wort zu sagen"

(intransitive verb) to have sufficient courage

"try it if you dare": "Versuchs nur, wenn du es wagst!" (: "... wenn du dich traust!")

(transitive verb)

to challenge to perform an action especially as a proof of courage or to confront boldly

"dared him to jump":  No direct translation! (alternative: zu etw. herausfordern)
"dared the anger of his family": No direct translation! (alternative: riskieren)

to have the courage to contend against, venture, or try

"the actress dared a new interpretation of the classic role": "Die Darstellerin wagte eine Neuinterpration der klassischen Rolle"

P.S.: I forgot to propose an alternative. "Mach schon! Du traust dich doch eh nicht!" is a provocative way to express a challenge.
Comment: +1 For the clear exposition. *Ich wette, du traust dich nicht* + *zu* + infinitive seems to convey the aspect of challenge well.
Comment: Zu meiner Schulzeit wurde das *Ich wette, du traust dich nicht* mit einem einzigen Wort ausgedrückt: **Hemmung!**


Working Collaborative with Other Departments

Question: My team has owned a marketing a project for about a year now that the marketing department would like to start having more ownership in and collaborate in. We owned it by default because no one their team ever did anything with it. The project manager has always resided on my team. As much as I would like to work collaboratively on it I feel like we still need a project manager though the marketing leader is reluctant to have someone as the project manager. My question would be is it wrong to want this process to stay on my team? Is it wrong to believe we need a project manager or champion who owns the process? My direct report believes that the process should be on our team and that it does need a champion or pm? How do I get the marketing leader on board to keep things as is?
Answer: I worked at a large corporation once where the marketing department managed to take control of a large portion of the IT budget, as IT was a slow, mid-range (AS/400) group of developers who had difficulty delivering modern e-Business projects in an Agile way (at a time where Agile "expectations" existed before Agile was used to deliver projects - hope that makes sense).  This situation descended into a corporate squabble as there was board level support for marketing (they could outsource development), but IT's reputation was in the toilet.   The reason I bring this up is I can see the same situation brewing here.  All I can say is everyone needs to be on the same team with respect to delivering value to the business and power struggles are going to impede that
Answer: Consider proposing the use of the DSDM Agile methodology.
DSDM is an Agile methodology that builds the business aspects of IT into the project with clearly defined roles for the IT and business personnel; the marketing staff here would be classified into the "business" roles here, though it's possible that not all business roles would be filled by people from marketing (the Business Sponsor role is often filled by the CEO, for instance).
Here is a page that discusses the specific details of the DSDM roles and their responsibilities: https://agile-mercurial.com/2019/04/03/dsdm-project-management-roles-and-responsibilities/amp/


At small axon diameters (<1 µm), why does myelination not increase neuronal conduction velocity?

Question: As per the diagram below (and other graphs available online), why do unmyelinated fibres have a higher conduction velocity than myelinated fibres when the axon diameter is less than around 1 µm?
Answer: Graphs like these are based on a complete cross-sectional area. Myelination adds thickness, so if you want to add myelin outside and keep the same diameter, you have to have a smaller lumen inside the axon.
As you can see in the "unmyelinated" plot versus diameter, smaller fibers have lower conduction velocity. Since the benefits of cross-sectional area are most important at small diameters (because the velocity changes with the squart root of diameter), for small diameter axons you end up losing more from losing internal area than you gain from adding external insulation.
If you keep the internal diameter the same and just add myelin, you will always increase the conduction velocity, but the total diameter including the myelin won't be the same anymore.
Comment: This explains it perfectly. So going from unmyelinated to myelinated is always beneficial in terms of conduction velocity, but it may not be in terms of space-saving. Thank you!
Comment: @pincushion44 Exactly, and space is at a premium in nervous systems!
Answer: That's observed due to passive conduction. With more area of cross section resistance is decreased (ohm's law). Myelin has just function of insulation the graph showing conduction in neuron fibre varying with thickness of neuron (hereby also thickness of myelin sheath).
Conduction is ruled by multiple factors not only just thickness of insulation. check this out https://www.ncbi.nlm.nih.gov/books/NBK10921/
When the area is so less than certain level the resistance is really high and insulation provided by myelin sheath works against conduction rather than supporting it. Conduction happens superficially instead in the bulk.
Where as in non myelinated fibre the insulation of myelin is not barrier.
Straight line tells me that my reason is legible probably since current is proportional to (1/R and hence) A
Comment: Sorry, I am slightly confused as to why insulation from myelin works against conduction when the area is low (and so longitudinal resistance is high)?
Comment: will try to make answer better after studying more about it
Comment: try that citation if it helps tell me.
Comment: It might also be possible that at smaller diameter cohesive forces of myelin sheath material close the node of ranvier and reduce it in significant amount


concat subsections of a video using ffmpeg

Question: I would like to take several subsections of a video and concatenate them using the concat ffmpeg filter. It's just like the the example in the FFmpeg documentation, except that all of the clips are from the same source video.
Here is what I am trying:
ffmpeg \
  -ss 1.0 -frames:v 20 -i myInput.mp4 \
  -ss 2.0 -frames:v 20 -i myInput.mp4 \
  -ss 3.0 -frames:v 20 -i myInput.mp4 \
  -filter_complex '[0:0][0:1][1:0][1:1][2:0][2:1]concat=n=3:v=1:a=2[v][a1][a2]' \
  -map '[v]' -map '[a1]' -map '[a2]' myOutput.mp4

When I try this, I get the following error (full output here):
Stream specifier ':0' in filtergraph description [0:0][0:1][1:0][1:1][2:0][2:1]concat=n=3:v=1:a=2[v][a1][a2] matches no streams.

A few things:

What's with the error? According to the stderr output, those streams do exist. What am I missing?
Shouldn't the -ss (and -frames:v) be reflected in the "Duration: ... start: ... " line of the stderr output when the inputs are listed?
Will the "-frames:v" option even work to specify the duration of an input? (apparently -t is only for output??) Is there a way to specify the duration of an input with seconds instead of frames?

Help me LordNeckbeard -- you're my only hope!
Answer: ffmpeg.exe -f concat -safe 0 -i "D:\Clips\concatepath.txt" -c copy "D:\Clips\ConcatinatedVideo.mp4"

Where concatepath.txt file is containing all videos path.
Here is an example
file 'D:\Clips\video1.mp4'
file 'D:\Clips\video2.mp4'


Does ordering by auto-incrementing PK ensure chronological order?

Question: Is it safe to assume that ordering by an auto-incrementing PK in Postgres will order the records chronologically, from a creation standpoint? I have a many to many relationship, from which I don't need to track anything else except the relationship itself and some form of order of creation. I am trying to decide whether I need to incorporate a timestamp column for this, or whether I can reutilize the existing auto-incrementing PK column for that same purpose.
Comment: Just add a `created_at` and `updated_at` timestamps. Then, create an index on the timestamps. It's always great for auditing the data - sometimes essential depending on the business requirements..
Answer: Assuming by "auto-incrementing" you mean the Postgres SERIAL pseudo-type, the short answer is "not always".
SERIAL columns are implemented using standard SQL sequences, which might generate out-of-order values when used by multiple concurrent sessions if the CACHE parameter is set to something more than 1. The manual states this:

[A]lthough multiple sessions are guaranteed to allocate distinct sequence values, the values might be generated out of sequence when all the sessions are considered. For example, with a cache setting of 10, session A might reserve values 1..10 and return nextval=1, then session B might reserve values 11..20 and return nextval=11 before session A has generated nextval=2. Thus, with a cache setting of one it is safe to assume that nextval values are generated sequentially; with a cache setting greater than one you should only assume that the nextval values are all distinct, not that they are generated purely sequentially.

Leaving CACHE value at 1 might hurt performance in an environment with high concurrency, so you will have to choose what is more important to you.
In my view, trying to repurpose SERIAL for tracking order of creation of records is not a good idea, because it potentially creates a maintenance problem: since the sequence's only promise is to provide some unique incrementing value to each nextval request, relying on its behaviour under one circumstance might cause your application to behave unpredictably when the situation changes, e.g. the sequence implementation details are modified in a future Postgres version, or changes in your workload require you to increase the CACHE setting. Using a proper timestamp for orderging is both safer and semantically clearer.
Comment: …but note that timestamps are not generally guaranteed to be unique, so in practice you'll still need to use something else (e.g. the auto-incrementing key) to break ties and give you a consistent order for records with identical timestamps. For records created by a single sequential process running on one node, a (timestamp, auto-increment-key) pair should _usually_ give a consistent order (modulo funny stuff like someone adjusting the system clock backwards). If you have a distributed system, clock skew becomes a potential issue.
Answer: What do you mean by the chronological order?
If there's a transaction 1 that begins before transaction 2, but ends after transaction 2, is the first transaction transaction 1 or transaction 2?
If you're using the SERIALIZABLE transaction isolation level, it guarantees that there is a total order for transactions: that is, there is some serial (non-parallel) order for the transactions that would give the same result as the transactions running in your real life parallel system.
Most likely, PostgreSQL sequences will not give the exact same ordering for values than the serializable total order. You could fix this by creating your own sequence: create a table with one row having one integer column, and update that row. However, if doing that, the parallelizability of your transactions suffers. It can even suffer in a manner that causes some of the transactions to fail.
One solution, as proposed by a comment, is timestamps. However, the timestamp order is not necessarily the same as the serial order that would give the same results.
(As a side note, you should be prepared for failed transactions in all cases. Deadlocks cause failed transactions. The SERIALIZABLE isolation level causes even more failed transactions. The proper way is to have exponential back-off and retry.)


What Chromium version does RaspberryPi 3.0 use?

Question: What version of Raspberry Pi 3.0 use? it just says chromium in the browser.
Comment: The version of the Pi isn't the important bit here; it's the version of Raspbian you're using that matters. You should [edit] to state that in your question — see https://raspberrypi.stackexchange.com/q/6974/58316 to determine your OS version.
Answer: when you type "chromium --version" in the terminal, it should output the version number you are using.
Answer: Another way, if you're on a desktop or full screen browser, would be to enter either of the following in the address bar of the browser;
about:

or...
chrome://version

Answer: Just a note that the version of Chromium is not dependent on the hardware (Raspberry pi 3.0) but rather on the image or distribution of linux, usually Rasperian. The current versions of Raspian (nicknamed 'stretch') ship with Chromium browser 60.0. To see the exact version, from a command line 'chromium-browser --version'. To upgrade to the latest: 'sudo apt-get install chromium-browser'.


Difference between ArrayList list = new ArrayList(); and Collection list1 = new ArrayList();

Question: I don't understand difference between:

ArrayList<Integer> list = new ArrayList<Integer>();
Collection<Integer> list1 = new ArrayList<Integer>();

Class ArrayList extends class which implements interface Collection, so Class ArrayList implements Collection interface. Maybe list1 allows us to use static methods from the Collection interface?
Comment: With `Collection list1 = new ArrayList();`, you can't call `list1.get(0);` for example (won't compile).
Comment: Closely related: [What is the difference between declaring List vs ArrayList?](http://stackoverflow.com/q/13709795/572670)
Answer: An interface has no static methods [in Java 7]. list1 allows to access only the methods in Collection, whereas list allows to access all the methods in ArrayList.

It is preferable to declare a variable with its least specific possible type. So, for example, if you change ArrayList into LinkedList or HashSet for any reason, you don't have to refactor large portions of the code (for example, client classes).
Imagine you have something like this (just for illustrational purposes, not compilable):
class CustomerProvider {
    public LinkedList<Customer> getAllCustomersInCity(City city) {
        // retrieve and return all customers for that city
    }
}

and you later decide to implement it returning a HashSet. Maybe there is some client class that relies on the fact that you return a LinkedList, and calls methods that HashSet doesn't have (e.g. LinkedList.getFirst()).
That's why you better do like this:
class CustomerProvider {
    public Collection<Customer> getAllCustomersInCity(City city) {
        // retrieve and return all customers for that city
    }
}

Comment: So list1 is an ArrayList, but can use only methods from Collection interfase? And method Collections.sort(list1) is acces only for list1, but not for list?
Answer: What we're dealing with here is the difference between interface and implementation.
An interface is a set of methods without any regard to how those methods are implemented. When we instantiate an object as having a type that is actually an interface, what we're saying is that it is an object that implements all of the methods in that interface... but doesn't provide is with access to any of the methods in the class that actually provides those implementations.
When you instantiate an object with the type of an implementing class, then you have access to all of relevant methods of that class. Since that class is implementing an interface, you have access to the methods specified in the interface, plus any extras provided by the implementing class.
Why would you want to do this? Well, by restricting the type of your object to the interface, you can switch in new implementations without worrying about changing the rest of your code. This makes it a whole lot more flexible.
Answer: The difference, as others have said, is that you are limited to the methods defined by the Collection interface when you specify that as your variable type. But that doesn't answer the question of why you would want to do this.
The reason is that the choice of data type provides information to the people using the code. Especially when used as the parameter or return type from a function (where outside programmers may have no access to the internals).
In order of specificity, here is what different type choices might tell you:

Collection - a group of objects, with no further guarantees. The consumer of this object can iterate over the collection (with no guarantees as to iteration order), and can learn its size, but cannot do anything else.
List - a group of objects that have a specific order. When you iterate over these objects, you will always get them in the same order. You can also retrieve specific items from the collection by index, but you cannot make any assumptions about the performance of such retrieval.
ArrayList - a group of objects that have a specific order, and may be accessed by index in constant time.

And although you didn't ask about them, here are some other collection classes:

Set a group of objects that is guaranteed to contain no duplicates per the equals() method. There are no guarantees regarding the iteration order of these objects.
SortedSet a group of objects that contains no duplicates, and will always iterate in a specific order (although that specific order is not guaranteed by the collection).
TreeSet a group of ordered objects with no duplicates, that exhibits O(logN) insert and retrieval times.
HashSet a group of objects with no duplicates, that does not have an inherent order, but provides (amortized) constant-time access.
Answer: The only difference is that you're providing access to list1 through the Collection interface, whereas you provide access to list2 through the ArrayList interface. Sometimes, providing access through a restricted interface is useful, in that it promotes encapsulation and reduces dependence on implementation details.
Answer: When you perform operations on "list1", you'll only be able to access methods from the Collection interface (get, size, etc.). By declaring "list" as an ArrayList, you gain access to additional methods only defined in the ArrayList class (ensureCapacity and trimToSize, for example.
It's typically best practice to declare the variable as the least specific class you need. So, if you only need the methods from Collection, use it. Typically in this case, that would mean using List, which lets you know it's ordered and can handle duplicates.
Using the least specific class/interface allows you to freely change the implementation later. For example, if you later learn that a LinkedList would be a better implementation to use, you could change it without breaking all your code if you define the variable to be a List.


How to show category just on specific pages?

Question: I am trying to find a way to hide a specific post category from all pages but one (and its child-/ sub-pages).
Let's say I have a page called "Fruits" and it's child-/ sub-pages are "Berries" and "Stone Fruits". Furthermore, I have created a post category "Fruits-Category" and some posts tagged to it. I want these posts just to be shown on the "Fruits", "Berries" and "Stone Fruits" page. Not on the home page, any archives or sidebars or any other pages. When googling, I just find examples for hiding categories on either the home page or the blog page.
Here is my code so far in functions.php:
function tpa_exclude_technology_cat( $query ) {
if ( !$query->get_queried_object_id('8') ) { // "Fruits"-page has id of 8
$query->set( 'cat', '-3' ); // "Fruits-Category" has id of 3
}
return $query;
}
add_filter( 'pre_get_posts', 'tpa_exclude_technology_cat' );

I am not sure how to get the child-/ sub-pages of "Fruits". Maybe there is a better way to solve this?
Thanks in advance!
Answer: Try this-
function tpa_exclude_technology_cat( $query ) {
  if ( $query->get_queried_object_id() != 8 || $query->get_queried_object()->post_parent != 8 ) { // "Fruits"-page has id of 8
    $query->set( 'cat', '-3' ); // "Fruits-Category" has id of 3
  }

  return $query;
}
add_filter( 'pre_get_posts', 'tpa_exclude_technology_cat' );

Comment: @TPA Are you looping through the posts using a custom WP_Query inside the page.php template file?
Comment: You mentioned, *"I want these posts just to be shown on the "Fruits", "Berries" and "Stone Fruits" page."* How are you doing that? Are you not using a custom loop for that?


Story of swayambhuva Shrinathji temple

Question: What is the story of self manifested Shrinathji Temple story of Rajasthan?
Comment: You mean the Dwaraka temple?
Comment: I have visited Shri nathji of rajasthan. I have no idea of dwarka
Comment: Sri nath ji temple is maintained by Rudra Sampradaya followers of Vaishnavism. They are direct followers of Vallabhacharya. https://en.wikipedia.org/wiki/Rudra_Sampradaya
Answer: The Story of Shri Nathji:
Shri Nathji temple is main temple for followers of Rudra Sampradaya in Vaishnavism which was propagated by Vallabhacharya
History
The Swarup or divine form of Shrinathji is said to be self-manifested.The idol of the Lord Krishna was being transferred to a safer place from Govardhan to protect it from the anti-Hindu, iconoclastic and barbarian destruction of the Mughal ruler Aurangzeb by the Head Goswami of the 1st House of Pushti Marg in 1669, Shri Dauji Maharaj. When the idol reached the spot at village Sihad or Sinhad, the wheels of bullock cart in which the idol was being transported sank axle-deep in mud and could not be moved any farther. The accompanying priests realised that the particular place was the Lord's chosen spot and accordingly, a temple was built there under the rule and protection of the then Maharana Raj Singh of Mewar.Shrinathji Temple is also known as 'Haveli of Shrinathji' (mansion).The temple was built by Goswami priests in 1672.
Legend
It is believed Shrinathji used to travel to Mewar to play dice with a Princess by the name of Ajab Kauri. She was upset whenever her beloved Shrinathji would go back to Vraj and asked him to stay with her in the palace. Lord Shrinathji said that one day He would make her palace His home. This palace is the current temple of Shrinathji.
Presently, Shrinathji is worshiped by priests from this kul (genealogical descendants) of Vallabhacharya, in all Havelis around the world, which have also been established exclusively by them.
Source

Story of swayambhuva Shrinathji temple


Understanding 'sort by name' behavior in Finder

Question: I don't understand the sort behavior I'm experiencing in Finder (MacOS Sierra). Is there anyway to get the 'sort by name' to sort alphabetically such that 0 < 9, a < z, and numbers < letters?
Comment: Have you tried sorting decreasing and then back to increasing in succession.  That worked for me.
Comment: Ya that didn't work for me.
Answer: Apple OS X uses "natural" sort order in which a string of digits is considered as a unit.
The Apple documentation is in the Finder section of this page.
An old article on Finder sorting that may still be useful is here.
I think Terminal may sort the way you want.  There are also several 3rd party alternatives to the Finder which may offer that kind of sorting.
Comment: thanks! I added the answer below using the documentation link you provided.
Answer: I was confused why 080c30.png was coming after files that started with numbers greater than 0 (ex: 1c0f28.png).
I followed the link to the documentation shared by Tom Gewecke above. It says:

Substrings of digits are sorted according to their numeric value, as opposed to sorting the actual characters in the number.

In this case, the leading substring of digits in 080c30.png is "80", which is greater than 1 (in 1c0f28.png). There is no way to change the sort behavior for finder afaik, but yes you can sort the files in terminal or via 3rd party apps to get the behavior I was looking for.


if the shared electrons in covalent bond revolves around their nucleus, how they hold the two molecules together?

Question: Covalent bonds are formed by sharing electrons. The pictures depicting this bond make it seem like that the shared electrons stay in a fixed/limited place. What happens in reality? If they rotate around their nucleus how the shared electrons hold the two nuclei in an atom?
Comment: Electrons don't rotate, nor do they rotate around their associated nuclei if we are taking about atoms in a molecule.
Answer: Let's consider a simple case, $\ce{H2}$. When the two nuclei come closer to each other (starting from a long distance), the electrons benefit in terms of energy because they now enjoy being attracted to two nuclei instead of just one. This energy gain is (partly) responsible for the bond dissociation energy, which needs to be invested in order to break the bond again. For a discussion on why the nucleus-electron interaction outweighs the electron-electron repulsion, see this question.


Quadcopter stability vs (PID error signal lag and sample time)

Question: The question I am asking is that, what is the effect on stability of increasing or decreasing both the sample time and lagging of error signal to PID. Does it helps in stability or degrade it?
Answer: A PID can provide great control, but it's a very unsophisticated technique -- it only understands error and correction.  The longer you wait between measurements, the larger your error will be each time.  (No surprises here, right?  It's the difference between moving 60 miles every hour and moving 1 mile every minute.)
The best performance that you can get from a PID happens when it runs (1) as fast as your sensor can supply accurate measurements, or (2) as fast as your actuator can make accurate adjustments -- whichever is slower.  If your sensor measurements aren't updating between PID ticks, your PID will overcompensate.  If your actuators aren't updating between PID ticks, you will notice that your PID gains only work for a limited range of the output (e.g. it works fine at 75% thrust but goes crazy at 55% or 95%).
Regarding accuracy: it may be necessary to average out individual measurements from a noisy sensor, which sacrifices the sample rate.  If that's the case, there really isn't much you can do here except lower your maximum speed.  You can experiment a bit to see how much averaging is sufficient for your application, but you can't really get around the limitations of the hardware itself.
Comment: Could you elaborate that bit in the last line of your second paragraph? About actuators being slower creating limited effective PID range?
Comment: Sure.  Think of the lag as a non-linear effect on your system, similar to [a dead band or a stick-slip cycle](http://blog.opticontrols.com/archives/77).  In that scenario, the $K_d$ component can line up with that lag effect over some range; you can tune as normal and things will appear to work fine.  But when you move out of that range, things will seem to be out of tune again.  There are many, many nonlinear effects to watch out for (like I said, PID is very unsophisticated), but I mentioned this one because it relates to lag.
Comment: Interesting! That makes me want to revisit PID controllers in a more critical and contrasted analysis. Any directions you could recommend?
Comment: Most of what I know comes from hands-on testing, not the literature.  (And with a hardware system that's already set in stone, your options are limited: to slow down the PID frequency, decrease the operating range, or try to improve your actuation model -- usually some hack -- to make things fit what a PID expects.)  I'd look for articles on finding the proper PID frequency for a given system.
Answer: In general, a system that is "discrete" will always be less stable, the less samples per time, the less stable it will be.
Imagine you are driving a car. You are only allowed to turn the steering wheel every 10 minutes. Can you keep the car on a curvy road this way?
To expand the example to answer your second question: don't drink and drive.
If your sensors are lagging, your ability to control the car are evidently reduced.
Comment: ok, so the sample rate is proportional to stability; but the sensors on high sensitivity gives more noise while on lower sensitivity(lagging signal) gives less error. So what do to with that. that is: non lagging => noise.
lagging => lesser noise.


difference between "pain" and "ache"

Question: I said " my arm aches me " and My teacher said "the arm sores not aches "
So both of the words describe illness , what is the wrong with using arm ache ?
Comment: 'Sore' is not a verb and 'ache' is not used with an object. The verb 'pain' is sometimes used and needs an object, but is rarely used for physical pain.
Comment: Would you please explaine further ? Maybe with examples ?
Comment: Note that you could say your arm *hurts*, which would be less specific than saying whether it was a *pain* or an *ache*.
Comment: Our sister site, ELL, is the more appropriate one to ask this question on, Avril. But there too they expect reasonable research (eg a dictionary definition stating that 'sore' is a verb or that 'ache' can take an object, or a definition not licensing these usages).
Answer: Neither ache nor sore can be used as you or your teacher suggest.
Ache, denoting a dull, continuous pain, is intransitive, so while you can say

My arm aches.

You cannot say

*My arm aches me.

Sore, however, is not even a verb, but an adjective (or noun), so you can say

My arm is sore.

but not

*My arm sores me.

Pain can be transitive, but today is almost always used figuratively:

It pains me to have to accuse one of my dearest friends of being a hypocrite …
Comment: You can also use "pains" as a non-figurative verb:  "My back pains me."  But it's not a real common usage.
Comment: @HotLicks: Oh, that pains me indeed! Sorry, I simply connected the DV with your comment.
Answer: Some note needs to be made of the difference between "ache" and "pain", from a sensory point of view.
ache typically refers to a discomfort felt over a relatively large section of the body.  Eg, you might say that your shoulder aches or your thigh aches.  The discomfort does not have any strong focal point.
(Of course, English being what it is, a headache breaks the above "rule" and often has specific focal points one can identify, vs being felt generally over a large part of the head.)
pain is more general, and, in some contexts, an ache is a type of pain.  But usually "pain" implies a discomfort that has a focus -- a particular point in the body that hurts, or perhaps (in the case of a muscle strain, eg), a distinct line of discomfort that is felt in the body.
sore is another word that has different implications in different contexts.  When you exercise hard and complain that your muscles are sore the next day, you usually mean that they ache -- there is typically no strong focal point for the discomfort.  But if there's a particular point on the body which, when pressed, produces significant discomfort, that's typically referred to as a "sore spot" or something of that ilk.
A pain, of course, is trying to keep all this stuff straight if you're not comfortable with the language.
Answer: "My arm aches" is proper.  I believe that "my arm aches ME" is incorrect because "aches," used as a verb, does not take an object like "me."  Saying "me" is redundant, because only you can feel your arm ache.
"The arm sores not aches" doesn't make any sense.  You could say, "My arm is sore."  "Sore" is not a verb and so "my arm sores" is incorrect.
Answer: There are a few romance languages which use the grammatical structure of "the body part hurts/aches me". But in English the proper structure is "My body part hurts/aches". Where as in those romance languages expressing pain uses a reflexive verb, in English they do not. (the reflexive nature of the phrase is generally reflected in the use of "My", which assumes that the pain being generated affects you. Where as in say, Spanish, "me duele la cabeza" (the head hurts me) assumes the part belongs to you because it wouldn't make much sense for someone else's head to be hurting you. Both structures omit an assumed piece of knowledge that would only be completed by such a phrase as "my head hurts me" but in neither language is that structure ever used.
(I would often make a similar but opposite mistake in Spanish by saying "me duele mi cabeza")

difference between “pain” and “ache”


Does a Steam Microwave with true Convection cooking use microwaves in the convection oven baking process?

Question: Does the convection oven baking feature still utilize microwaves to do the baking/broiling etc?
Answer: Such things can be make and model dependent. What can give you a hint is what the documentation says about metal cookware being or not being permissible when using the convection mode. If in doubt, ask the manufacturer.
Answer: It should not, in principle, continue to microwave. But I have heard of combos which continue to microwave even though the knob settings suggest they shouldn't. So, you will have to test it for yourself. If you try baking some bread and it behaves like microwaved aferwards, your microwave is staying on.


Why aren't pictures of Pluto darker than those of other planets?

Question: Just as the intensity of the light from a candle decreases with distance, I would expect the light from the sun to illuminate the distant planets less than the closer ones. However, the pictures of Pluto from New Horizons don't seem any "darker" than those of the other planets. Have the photos been edited in some way to correct for the lower light? Or is there something else going on? My first thought was that this problem could be solved with longer exposure for each image, but I imagine that would cause blur problems given the speed of the probe.
Comment: A larger lens could be the solution as well. Larger lens = more light gathered.
Comment: Related: http://physics.stackexchange.com/q/206048/
Comment: Cross-site duplicate: [*How did New Horizons take such well lit pictures of Pluto?*](http://astronomy.stackexchange.com/questions/11403/how-did-new-horizons-take-such-well-lit-pictures-of-pluto)
Answer: This question has been asked and answered (by me) on Astronomy Stack Exchange:

It's brighter on Pluto than you think.
NASA developed a tool called Pluto time, which tells you when at your place the ambient light conditions are similar to the ones on Pluto.  This occurs when the Sun is only 2° below the horizon!  That's quite shortly after sunset, and considerably before the end of civil twilight, which is when it's 6° below.
All of these photos were taken at local "Pluto time":

Pluto time, according to NASA.  Source: NASA
To answer your question: all it takes is a slightly longer exposure time / larger aperture than taking photos closer to the Sun.  It's easily bright enough for outdoor activities, so have fun glacier hiking on Pluto!


How many fingers on the brakes for a road bike?

Question: For any reasonable mountain bike, it is advisable to keep one finger on each brake at all times. How does this advice transfer to road bikes?
Answer: While @Batman makes some good points, round here we have some descents on narrow country lanes with high hedges and poor road surfaces. Modulating speed is much more important than on the open road. You might get up to 50 or even 60km/h on a clear stretch but then have to brake for a blind bend. You don't want to rely on braking too hard because of loose gravel or patches of mud on the road. We do also have open road fast descents but they tend to be on busier roads and I won't go into them.
I'm lucky enough to have discs on a tourer and can use continuous light braking at the back to control my top speed, then slow down with the front brake before a bend.
I prefer to do anything tricky on the hoods (these descents, traffic) and can crouch quite low if I do get a nice straight. So I like to have 2 fingers on the brakes as the index finger is very near the pivot - with index and middle fingers I've got all the stopping power I want (subject to road surface). In the drops, one finger is enough because it's got more leverage, but only if I've checked the brifters - when badly adjusted the tab you press when shifting to a bigger cog limits braking when it hits my fingers.
I apply similar methods to other cases when sudden braking might be required, like in traffic (1 to 3 fingers depending on road surface, speed etc.)
Comment: So 2 from the hoods, 1 from the drops? Probably my low-end disks haven't broken in yet, because to stop I seem to need 2 from the drops or 4 from the hoods.
Comment: @MiroslavVitkov that's right but hand size with respect to brake levers and adjustment also plays a part.  On a clean dry flat road stopping really hard one more finger might help but I've skidded the front wheel a couple of times recently (luckily briefly and in a straight line) so am wary
Comment: You'll probably spend most of the time on the hoods like many riders where you may keep your index-fingers on the brake-levers at all times.
Comment: @Carel possibly most of the time because I use the hoods in slow stuff, butnot most of the distance. I'm very comfortable in the drops for long periods  when just getting on with riding
Comment: @Chris H : It depends on the type of road bike and the difference of height between saddle and bars. With older or retro bikes the bars are almost level with the saddle and the drops are a much favoured riding position. In new style race bikes where the bars sit much lower and the rider has his hands on the hoods for most of the time.
Comment: @Carel absolutely. Mine is new but looks quite retro, partly for this reason
Answer: Depends.
Let us define the parts of the bar according to this answer.

If you're riding in the hoods, you might have your fingers over the brake levers.
If you're in the drops, you're (usually) able to reach them (moreso on newer levers), but you probably don't have your fingers on the brake levers.
On the tops, you probably won't be able to reach the brake levers unless you have interrupter or suicide levers.

Having constant access to the brakes isn't as necessary as it would be in mountain biking (where you're spending a lot of time modulating the brakes; road riding does this very little, primarily to stop, sometimes slow down or clean the rims in anticipation for braking). Of course, you'll pick also depending on the environment -- if you're riding in city traffic, you'll likely ride in a position that you have the best visibility and brake access. Note mountain bikes typically have one position; possibly an additional position via bar ends (unless you have a relatively rare drop bar mountain bike).
You'll choose your riding position according to preference or comfort (switch hand positions for comfort) in many cases, which will dictate your brake access.
Comment: Agreed.  Roads tend to have better range of sight, so you can see whats coming up from further away.  If you are in a bunch or otherwise enclosed, your hands should be on the brakes.  If the road is open and clear it doesn't matter.  If climbing and aero is unimportant, then on the tops is fine - there you brake by stopping pedalling, and let the hill stop you.... That doesn't take long!


Story about a neural computer personality implanted and communicated to using subvocalization

Question: I was watching a piece on 60 Minutes the other day about the MIT Media lab and one invention being worked on was the use of subvocalization to communicate with the machine linked to the internet.  It reminded me of a story that I read at least 40 years ago in which the protagonist had an implanted computer that he subvocalized to ask it questions and it responded via bone conduction that only he could hear.  It also had the capability of remote sensing. I don't remember much about the story although a second such machine was implanted in another person and the two machines were able to communicate with each other directly.  Anyone know of this book?
Comment: IIRC, in the direct sequels to Ender's Game, Ender eventually ends up with an implant like that. But it has been a long time since I've read those books, so I might not be recalling it right.
Comment: @Xantec [Ender's Game](https://en.wikipedia.org/wiki/Ender%27s_Game_(series)#Novels_in_the_series) was only written 30 years ago, and the ones with two characters having the earrings only 25. There was an internet controlling program/person that saw essentially everything and the sub-vocalization being less than perfect became a plot point in damaging a marriage.
Comment: Having vague memories of something like this maybe in Zelazny's *Unicorn Variations*.
Comment: Somtow Sucharitkul used "subvoc" microphones in his Mallworld stories. Many characters spoke to each other, and with various computer assistants.
Answer: Perhaps it is Delay In Transit by F. L. Wallace.
A computer (intelligent AI) implant was talked to through sub-vocalization.  It also has some abilities to scan at a distance.
Tech level was space opera with space travel and alien species common.  The Galaxy had many many inhabited worlds.  FTL Travel was real, though it was still time consuming.  Lack of FTL Communication meant there was no easy way to communicate between systems, other than by courier.  Schedules of flights between worlds were very problematic, with delays of several days common, and several weeks possible.  Missing a connection could mean a delay of months or years.  The protagonist's implant was top-of-the-line secret tech and he had it because of his job.
The protagonist (Cassal) had his ID stolen, preventing him from leaving through the spaceport.  A stolen or counterfeit ID could be used, but the user had to get a minor lobotomy for it to work, as the ID was matched against a brain scan.  This surgery was minor enough that it was a viable option taken by many, but the protagonist did not take that route.  He had already been traveling for several months, and without FTL communication, contacting Earth for a replacement ID was not an option.
He finds that his implant allows him to create a duplicate ID, as it has access to his brain to do so, though it does require prodding, poking, cutting, and stabbing to get the correct brain readings.
The femme fatale of the story (Murra Foray) is an alien woman (human appearance) who has also lost her ID and is trapped on the planet.  Her nickname for him is "Teddy bear".
Murra's species (Huntner), has exceptional hearing and she was able to hear everything that the Cassal and his implant had talked about, discovering how he created a duplicate ID.   She render's him unconscious and steals his implant.
Cassal knows the general plans for the implant and has portions of one secretly created by various different shops, so that no one has the full plans.   One such shop is an utter failure, as the amphibian aliens' stumpy fingers cause them to create a device the size of an interplanetary drive instead of something that could be implanted.
Once he successfully assembles and implants his new device, he is able to contact his previous implant, who is now willingly helping the woman.  His new implant, aided by an external power supply he added, is much more powerful than the old, as it is able to communicate instantaneously over FTL distances (she is already travelling) and it is able to render her unconscious over the link.
His previous implant explains that because of a quirk of her species' brain, the lobotomy is not a viable option for her and that she had to steal the implant to create a new ID, and that her use of "Teddy Bear" indicated that she very much liked him.
The story ends with the protagonist planning on following her after he finished his mission.
Comment: A quick scan on Project Gutenburg does not match the story I remember to that name.   I believe that I did read it in a similar magazine like Analog or Asimov though.   The story I remember was not long enough to be a novel, though I suppose it could have been a section of a serialized novel.
Comment: That story is "Insidekick" by J. F. Bone.
Comment: That's because it isn't! But it *is* "Delay in Transit" by F. L. Wallace. (I read both about a year ago when I went through all the *Best from Galaxy* books and confused the two. (I shudda checked first!)
Comment: That is it!   Thanks.   I'll edit in the firmer details later.
Comment: "Delay in Transit" IS the story that I was looking for! Great!  I was amazed that it was written so presciently in 1952, when I was 1.  And now I see the 60 Minutes episode on the MIT Media Lab that has what would be an early version of the tech described in the story.  Of course that is without an internet, per se, as that was not invented yet. Thanks a lot for the memory.
Comment: A week or so ago, I had actually remembered this story, and had thought to try to track it down, but had not yet got around to it.
Answer: Possibly Heinlein
1951 novel The Puppet Masters:

"The sort of phone my Section uses is not standard; the audio relay is buried surgically under the skin back of my left ear - bone conduction."

plot summary:

In the summer of 2007 Earth is under clandestine attack. Slug-like creatures, arriving in flying saucers, are attaching themselves to people's backs, taking control of their victims' nervous systems, and manipulating those people as puppets. The Old Man, the head of clandestine national security agency called the Section, goes to Des Moines, Iowa, with Sam and Mary, two of his best agents, to investigate a flying saucer report, but much more seriously the ominous disappearance of the six agents sent previously. They discover that the slugs are steadily taking over Des Moines, but they cannot convince the President to declare an emergency.
Sam takes two other agents and returns to Des Moines to get more evidence of the invasion.
Comment: I know "The Puppet Masters" well.  No computers being talked to over the phone.


What exactly is $\langle x |$?

Question: It's a linear functional, but what exactly does it do? It maps a wavefunction $|\psi \rangle$ to an element of $\mathbb C$, but what.. exactly does that mean? I know heuristically it maps $\psi$ to its position basis, but from its description, how does it do this?
Comment: related to https://physics.stackexchange.com/q/364208/
Comment: @ZeroTheHero I'd  call it an exact duplicate in skewed language.
Comment: Dirac, in his book, Ch III.20, cares to define it as |⟩=(̂−)|0⟩$\sqrt{2ℏ}$,
where the standard ket acted on is the translationally invariant vacuum, so ̂|0⟩=0, that is, the state |⟩ for *p* =0.
Comment: Is part of your question why $\langle x|\psi\rangle=\psi(x)$?
Answer: The object $\langle x\rvert$ has several mathematical properties, however one should take some care in dealing with it.
The usual physical "definition" is the following: given a wavefunction $\lvert \psi\rangle\in \mathscr{H}$ describing a (non-relativistic) quantum particle, then $\langle x\vert \psi\rangle=\psi(x)$ is the value of the wavefunction at $x$, and $x\mapsto \lvert \psi(x)\rvert^2$ is the probability density for the particle's position.
The above "definition", however, is not mathematically accurate. There is one foremost problem: there is no set of everywhere defined functions from $\mathbb{R}^d$ to $\mathbb{C}$ forming a complete Hilbert space. If one starts with smooth functions, such as $C_0^\infty(\mathbb{R}^d)$ or $\mathscr{S}(\mathbb{R}^d)$, and puts an inner product on it, the result space is not complete with respect to the topology induced by the inner product. Taking the completion, one usually gets a Lebesgue (or Sobolev) space, with the typical exaxmple being $L^2(\mathbb{R}^d)$. Such space consists of equivalence classes of almost everywhere defined functions, and these objects may not be defined in some points of $\mathbb{R}^d$ (because, roughly speaking, a point is not measurable).
Therefore, the functional $\langle x\rvert$ can be defined rigorously (by the above definition) only on a subset of the Hilbert space of wavefunctions (albeit a dense one). From now on, for simplicity let us assume the space of wavefunctions to be $L^2$. One choice for the dense subset of definition of the functional could be $C(\mathbb{R}^d)\cap L^2(\mathbb{R}^d)$, however the most natural one (for many interesting reasons that would be too long to discuss here) is the Schwartz space of rapidly decreasing functions $\mathscr{S}(\mathbb{R}^d)$. The functional $\langle x\rvert$ is, with respect to the usual topology of the Schwartz space, continuous for all $x\in\mathbb{R}^d$, and linear as well (this is easy to check). It is therefore a so-called distribution, belonging to the space $\mathscr{S}'(\mathbb{R}^d)$.
Physically, the set of distributions $\{\langle x\rvert\}_{x\in\mathbb{R}^d}$ is thought of as a "position basis", because heuristically these distributions behave as eigenvectors for the position operator. This is, however, only true in a weak sense: given any Schwartz wavefunction $\lvert\psi\rangle$, and the position operator $\hat{x}$, then $\hat{x}\lvert\psi\rangle$ is still a Schwartz function, whose value at $x$ is given by $\langle x\rvert\hat{x}\lvert\psi\rangle=x\psi(x)$. Therefore, since $\hat{x}$ is self-adjoint, it can be seen as acting on the left on the distribution in the following way: $\langle x\rvert\hat{x}=x\langle x\rvert$ (a sort of eigenvalue equation). Nonetheless, let me remark that $\langle x\rvert\notin L^2$, and therefore it is not a true eigenvector of the position operator (only true wavefunctions can be eigenvectors). It is a so-called generalized eigenvector. There is a (bit complicated, and in my opinion not so useful for quantum mechanics) reasonably well-developed mathematical theory of generalized eigenvectors for operators with continuous spectrum, that was developed mostly by the russian school (Gel'fand, Shilov).
Answer: For any vector space you can define a set of linear functionals that map the elements of this vector space into numbers.Nobody, i belive, cares how. It just does that. By this definition, space of linear functionals constitutes a vector space in its own right. For this vector space we can define such functionals which, when acting on the elements of the original vector space basis give just one or zero. These are called dual basis vectors of the dual space, dual space being just this space of linear functionals. With these functionals defined in this way we can write dual vectors in this dual basis and act on vectors. We can have inner products and such things.It is mathematicaly more meaningfull to define inner or scalar product in this way.
Answer: I think, for learning QM, it's best not to worry about what
$\langle \psi |$ is. Rather, focus on $|\psi\rangle$---a state vector, and $\langle \phi | \psi\rangle$---an innner product between one state vector and another. If you are still bugged by what $\langle \psi |$ is, then say to yourself "it's the Hermitian conjugate of $| \psi\rangle$".
The combination $\langle B | A\rangle$ has many useful interpretations. Rather than saying merely the true but rather abstract "it maps from a state to a complex number", you can keep in the forefront of your mind all of the following:
$\langle B | A\rangle$ can be thought of as "the overlap of $|A\rangle$ and $| B\rangle$" or "the degree to which $|A\rangle$ is like  $|B\rangle$" or "the coefficient of $|B\rangle$ if you write $|A\rangle$ as a superposition of $|B\rangle$ and other orthogonal things" or "that which, when mod-squared, gives the probability that a measurement of a system in state $|A\rangle$ will yield $|B\rangle$."

What exactly is $\langle x |$?


Gnome keyring stays unlocked permanently

Question: It used to be that my gnome keyring would go back to being locked after I rebooted and I'd have to enter the passphrase to unlock again, but now it stays unlocked unless I manually lock it with seahorse.  How do I restore the old behavior where the keyring relocks on reboot?
Answer: It turns out that gnome keyring stored the passphrase for my default keyring in a special keyring named "Login", and unlocked that keyring with my login password.  The PAM config files for console login and SDDM login use the gnome keyring PAM module.  It can be disabled by commenting out the lines containing pam_gnome_keyring.so from all files containing that string in the directory /etc/pam.d; this should make it so that you have to manually enter the passphrase to unlock your keyring.


Why did Terry Gilliam include Jeffrey as a character in Twelve Monkeys?

Question: The movie La jetée has already the story of 12 Monkeys, including also key-settings like the airport and the mall. But there is one big difference in 12 Monkeys to the older movie: Terry Gilliams included Jeffrey Goines, who plays an important role in his movie. Why did he include Jeffrey?
Answer: Interestingly Gilliam did not write the screenplay for 12 Monkeys, it is a rare example of a Gilliam movie that he did not start but was brought on-board after the rights had been picked up by the studio and a screenplay had been written by David and Janet Peoples.
That said, La jetée is 28 minutes long. I imagine that the writers could not sustain the story for 90+ minutes with just the main characters of the Narrator and The Woman, so introduced the both the disease as the cause of the 'end of the world' rather than a nuclear war, and Jeffrey as a character for Cole to interact with and start to obsess about stopping him.
I also imagine that when they came to rewrite the story, that a plot of a disease being deliberately released by eco-terrorists plays into the fears of people in the 90's more than people in the 60's when the original was made with a nuclear war story. This alternative back-story also makes it plausible for Cole to attempt to stop the apocalypse from happening as a driver for a lot of the action.
Really 12 Monkeys is not a remake of La jetée, as it says in the credits, it was inspired by the original.  In La jetée the narrator is also sent into the future where he brings back technology to help his broken society and is not killed by present-day cops at the Airport.
Comment: Ah, I had forgotten that it was a nuclear destruction in La jetée.
Comment: at end of La Jette the man is indeed killed at the airport in the past. He is killed not by airport police but by a scientist from the future who was sent back to do the hit. just like 12 Monkeys, the man fell in love in past and tried to stay there, against orders.


Where is the North of the Universe

Question: Does it exist North of the Universe? (Which is probably used for determining coordinates of far galaxies.)
If so, then where it is?
On what is it aligned? (Is it orientated on Earth, Sun, Milky Way, Local group or on something more bigger?)
Answer: Sort of... There is a system called the International Celestial Reference System (ICRS) which has center at the Solar System Barycenter (normally inside the Sun but not the same as the Sun's center) and which has the x and y axis in the plane of the Earth's equator and the z-axis ("North" if you will) pointing towards the Celestial Pole. The x-axis points towards the equinox where the plane of the Earth's orbit and the plane of the Solar system (the ecliptic) cross (on average; this gets complicated quickly as everything related to the Earth is wobbling about on different timescales).
Note although this reference system is close to the older mean equator and equinox J2000 or FK5 system it's not actually the same as it is now defined by a set of several hundred very distant extragalactic radio sources which are called the International Celestial Reference Frame (ICRF) and which we assume don't move on the sky. The latest version of this frame is called ICRF3 and was formally adopted at the IAU General Assembly last year in Vienna. More details on how the reference systems and frames work at the USNO page on the ICRS
Answer: There are coordinate systems used on various scales, with the ecliptic system(s) useful for denoting where on Earth's sky things are, galactic coordinates for objects in and around the Milky Way, and the supergalactic coordinate system for nearby galactic clusters. This is aligned along the supergalactic plane, a plane most local galaxy clusters are aligned with. The zero point is the intersection of this plane and the galactic plane. In the SGC the north supergalactic pole is approximately RA = 18.9h, Dec = +15.7° (epoch J2000), which seems to be somewhere in Aquila. The zero point (SGB = 0°, SGL = 0°) lies at 2.82h, +59.5°, between Perseus and Cassiopeia.
The ICRS is basically the ecliptic system but centred on the solar system barycenter and oriented relative to a number of distant extragalactic radio sources unlikely to move much. So "north" in this system corresponds more or less to "north" on the usual sky sphere.
So I think one can make decent arguments that there are two possible "north poles of the universe" depending on which coordinate system one prefers.
Comment: In fact, there are five North poles (for horizontal (alt-az), ecliptic, equatorial, galactic and supergalactic coordinate system). But the first three poles are not universal and are changing every day, that isn't recommended for big sizes. So galactic and supergalactic systems are only correct for those North poles. +1

Where is the North of the Universe