How to copy selected features from one sde to another using ArcObjects?

Question: Assuming I have two SDEs or other datasources with the same datamodel. One contains features the other one is empty. In ArcMap I have layers from both datasources in my table of contents. Now I would like to copy some features that are already selected in the map view from one sde to the other using C# and ArcObjects. What would be the best way to do this?
Comment: Have you considered using arcpy for this? Yes you can do it in ArcObjects. No, you probably shouldn't.
Comment: I agree with this comment. My answer below requires quite a bit of code. This can actually be done with less code by writing an ArcPy script and invoking it from Visual Studio.
Answer: Assuming that your features are non-complex, you will want to use an Insert Cursor (method 1). If your features are complex, you must use IFeature.Store() (method 2).
See the following code from this link (It's in VBA, but shouldn't take long to translate over)
Public Sub LoadFeatures()
    Dim pMxDoc As IMxDocument
    Dim pFeatureLayer As IFeatureLayer
    Dim pInFeatureClass As IFeatureClass
    Dim pOutFeatureClass As IFeatureClass
    Dim pQueryFilter As IQueryFilter
    Dim pFeatureCursor As IFeatureCursor
    Dim pFeature As IFeature

    'For simplicity sake, load features into the feature class
    'selected in the table of contents
    Set pMxDoc = Application.Document
    If pMxDoc.SelectedItem Is Nothing Then Exit Sub
    If Not TypeOf pMxDoc.SelectedItem Is IFeatureLayer Then Exit Sub
    Set pFeatureLayer = pMxDoc.SelectedItem
    Set pOutFeatureClass = pFeatureLayer.FeatureClass

    'Open a shapefile containing the features to load into the geodatabase
    Set pInFeatureClass = OpenFeatureClass("d:\data\usa", "counties")
    If pInFeatureClass Is Nothing Then Exit Sub

    Set pQueryFilter = New QueryFilter
    Set pFeatureCursor = pInFeatureClass.Search(pQueryFilter, True)
    Set pFeature = pFeatureCursor.NextFeature
    Do While Not pFeature Is Nothing
        'The next two lines control which loading method is used
        'To use an insert cursor, comment out the second line
        'To use CreateFeature/Store, comment out the first line
        InsertFeature pOutFeatureClass, pFeature.Shape
        'CreateFeature pOutFeatureClass, pFeature.Shape
        Set pFeature = pFeatureCursor.NextFeature
    Loop

    'Refresh the display
    pMxDoc.ActiveView.PartialRefresh esriViewGeography, Nothing, Nothing

End Sub

Method 1: an insert cursor
Private Sub InsertFeature(pFeatureClass As IFeatureClass, pGeometry As IGeometry)
    Dim pFeatureBuffer As IFeatureBuffer
    Dim pFeatureCursor As IFeatureCursor

    Set pFeatureCursor = pFeatureClass.Insert(True)
    Set pFeatureBuffer = pFeatureClass.CreateFeatureBuffer

    Set pFeatureBuffer.Shape = pGeometry
    pFeatureCursor.InsertFeature pFeatureBuffer
End Sub

Method 2: CreateFeature/Store
Private Sub CreateFeature(pFeatureClass As IFeatureClass, pGeometry As IGeometry)
    Dim pFeature As IFeature
    Set pFeature = pFeatureClass.CreateFeature
    Set pFeature.Shape = pGeometry
    pFeature.Store
End Sub

Opening the feature class:
Public Function OpenFeatureClass(strWorkspace As String, strFeatureClass As String) As IFeatureClass
    On Error GoTo ErrorHandler

    Dim pShpWorkspaceName As IWorkspaceName
    Dim pDatasetName As IDatasetName
    Dim pName As IName

    'Create the workspace name object
    Set pShpWorkspaceName = New WorkspaceName
    pShpWorkspaceName.PathName = strWorkspace
    pShpWorkspaceName.WorkspaceFactoryProgID = "esriDataSourcesFile.shapefileworkspacefactory.1"

    'Create the feature class name object
    Set pDatasetName = New FeatureClassName
    pDatasetName.Name = strFeatureClass
    Set pDatasetName.WorkspaceName = pShpWorkspaceName

    'Open the feature class
    Set pName = pDatasetName
    Set OpenFeatureClass = pName.Open

    Exit Function

ErrorHandler:
    Set OpenFeatureClass = Nothing
End Function

Comment: Way to put in the effort!  Two comments though.  When you use an Insert Cursor, you should try to create the Feature Cursor and Buffer outside your load loop.  In the example above, I think you are creating a new cursor and buffer for every feature.  Also, you may want to release the COM objects (Marshel.ReleaseCOMObject) so that they release the locks faster.
Answer: The easiest way I can think of is to either copy and paste the features or use the Copy Features GP tool.  That doesn't use C#.
If you really want to do with using C#, you could create an add-in or GP tool.  You could use search and insert cursors to actually copy the features.  Or, you could call the Copy Features GP tool from C# to do the work.


How to say copycat?

Question: I posted a status on Facebook and 20 minutes later someone else posted the exact same one. Google translate spits out 复印机 for copycat which looks pretty weird to me (the 机 at the end). Nciku gave me 模仿者 which looks better (the 者 at the end). How can I say something akin to 'copycat' in Mandarin?
Answer: 模仿者 means imitator, which isn't necessarily negative, and is used more for behavior imitation instead of content crib, but I think it is fine to use for your case.
For intellectual property plagiarism, the common words are 抄袭 (lit. copy and assault) and 剽窃 (lit. rob and steal). Both words are formal and strong but the latter one is even stronger. You can say someone is a 抄袭者 if he cribbed your exam answer, or 剽窃者 if he plagiarized your work.
Note in Chinese, xx者 usually indicates a behavior pattern or long-term state, while in English -er form is merely a language tool to convert a verb into a noun and is commonly used for one-time actions. So if you call someone 模仿者 it usually means this person always imitates somebody. If it's just this one time, I'd prefer to say '他抄(袭)了我的状态更新' instead of '他是个抄袭者'.
BTW if that person is not a human account, like a robot who cribs status updates and wall posts to look credible, we call them 僵尸(账)号 (lit. zombie account), 机器人 (lit. robot) or 僵尸粉 (lit. zombie follower).
Answer: In this context, I would use:

跟屁虫 [gēn pì chóng]

Similar to the English word "copycat", it is an informal noun used to describe a person who imitates, tags along or copies the idea or behaviour of another person.
Answer: 山寨。

China is home to copycatters. 中国是山寨之乡。
Every innovation gets copycatted by China. 每个创新都被中国山寨。

In your example however, 抄袭 and 剽窃 are the most accurate.
Answer: 复读机
维基百科页面
"你复读机啊你?"
Stupid character counter bah

How to say copycat?


Change multiple file names in sub directories in single line

Question: I have a directory named backup. Backup contains several subdirectories named monday, tuesday, wednesday... each subfolder contains file named filename.txt
I want to change all names filename.txt to someothername.txt.
How can I do that in one line in bash?
Answer: for f in backup/*/filename.txt; do mv "$f" "$(dirname "$f")/someothername.txt"; done

Answer: And this is if you want to keep the basename and just change the extension in a bunch of files located in some subdirectories:
for f in ./*/*.yaml;
   do mv ${f} "$(dirname "$f")/$(basename ${f%.*}).yml";
done

or
for f in ./*/*.yaml;
   do mv ${f} "${f%.*}.yml";
done


I'm writing a YA fiction book. Trying to make the character more layered

Question: I'm writing a YA fiction book. How do I make the character different, yet understandable, and what are your suggestions for keeping track of information you have placed in your book? For instance a timeine or smthg like that.
Comment: Welcome to writing. Please clarify what you mean by making your character more layered (implies complex) vs. different yet understandable (implies relatable but unique) vs. keeping track of information (you, or the character, and to what end)? Also it would be helpful to know a little more background. Sorry, I'm struggling to tell what your goal is.
Comment: These appear two separate questions. Perhaps for searchability better to make them such.
Answer: Layered characters
The question of layered characters is a big one. Basically how to write characters in general, but here are some things to get you started:
Goals and motivations
Give all your characters goals and motivations, even the small ones. Maybe the taxi driver is driving his taxi not to make money driving customers but to get social interaction? Use goals and motivations to break out of clichés. (So maybe the taxi driver then rather drives his cab to prove his thesis for his manifesto: that mankind is evil and needs to be eradicated...)
Values
Give the more complex characters values. Especially helpful if they have conflicting values. E.g. being a good parent and being a paid author. There's room for some drama when trying to make those two work simultaneously. Here are more examples of values to get you started.
Emotional wounds
Some select characters could be much helped by having an emotional wound in their backstory. I find they really make you understand and see a character come alive.
Organizing your character and world data
I always spend way too much time planning and outlining my texts, and then, when I start typing, something happens at the tips of my fingers and plans need to change (ok, most plans don't survive that meeting with reality). So I generate information before the writing and then while I write.
I use Word and Excel, Scrivener, DokuWiki, yEd, Aeon timeline, I've even used Gramps for complicated family trees. I keep everything (but dokuwiki) in my Dropbox.
So my answer would be to use what you think will work, don't be afraid to change if it doesn't work and try to keep it all organized in the oldest and safest system in computing (files and folders, backed up and kept in some cloud drive like Dropbox—I use DokuWiki because it keeps its data in files than I can backup and read even without DokuWiki if the worst should happen).
Answer: Keeping characters different; write down your characters traits and have it nearby. When you have another character idea, write it down as well and compare it with your other characters. If it's the same or close to another character, you should probably just tweak the existing one. Of course, you can have people who are pretty much the same(ie Fred a George in harry potter), which can be useful sometimes.
Making it understandable; If you don't understand your characters, then the audience probably doesn't either. I would recommend reading the story through but imagine you know nothing about the story and are just reading it for the first time. If you have a hard time with this, beta readers will be able to help.
Keeping track of information; Write it down. Of course, you should be doing this when you're writing the story, but it helps to have a sheet with the main points on it for easy reference. If you need to go back for a quote or something, then you'll have to browse through your story to find it to make sure you're quoting it right.
Good luck!


Where does the 'no' come from in tsukuru(no)? Is it a particle or part to tsukuru

Question: So i'm trying to figure this out why you put a の with a 作る(to make)...i.e. mary さんはすしをつくるのがへだです...
Answer: の is used to make a noun clause just like こと is.
For this function, の and は are roughly interchangeable.
I think の is more frequently used than こと in daily conversation, because の could be pronouced more easily than the other.
Answer: In order to describe a verb or add more sentence onto a verb you have to first turn it into a noun, with either の or こと. So, here the whole phrase すしをつくる acts as one noun when の is attached, and then you just continue as normal. ~がへたです。
Other examples of this same this happening:
本を読むのが好きです 読む + の
やったことないです。 (やる)やった + こと
そうなんです。 (です・だ)な + ん(の)


How do I set up a has_one through association through a has_many through association?

Question: I have a User model, a Membership model, and a Club model.  I have set up the following associations:
Club.rb
has_many :memberships
has_many :members, through: :memberships

Membership.rb
belongs_to :user
belongs_to :club

What I want now is to have a has_one :organizer on Club that retrieves a single User record based on the member with the organizer attribute set to true in the join model.
How do I set up this has_one association?  I've tried going through the memberships association, but an exception is raised that the memberships is a collection and needs to be singular.
Answer: I think I just figured it out...but in case someone else needs to know..
has_one :membership, conditions: ['memberships.organizer = ?', true]
has_one :organizer, through: :membership, source: :user


How should a secondary supervisor take an active, responsible role in student supervision?

Question: In practice most of cases of joint supervision I have observed fall under one of the following categories:

Secondary* supervisor attends occasional joint meetings and may read
drafts of manuscripts but does not play much of an active role.
Secondary supervisor has a particular area of expertise that the first lacks (especially in interdisciplinary projects), and provides training and advice in this area, but does little outside of this.

As a postdoctoral researcher I am starting to get involved with supervision of Masters or PhD students. Currently my contribution falls largely under (2) above. My most active contributions might be along the lines of "I've noticed you're having difficulty with process X, shall we have a meeting to talk it through?".
I would like to take a more active, responsible role as a secondary supervisor, for two reasons. I would like to gain some experience in supervision in preparation for the day when I may act as a primary supervisor. I also feel that as a joint supervisor I should be taking on a bit more of the responsibilities of the role, rather than just being an extra source of advice. However, I can see that in some aspects of supervision it's probably better to have a single point of responsibility and a single person who is seeing the whole picture.
I have tried talking to the lead supervisor about this, who was encouraging but fairly vague and didn't suggest any specific changes to what I am currently doing. I think I will need to be proactive and make suggestions myself.
What are some practical ways that a secondary supervisor can take on more responsibility, and make a more active contribution, within the student's supervision?

*I'm aware of some cases where the person who is officially designated as the "first" supervisor actually does very little and most of the job is done by a secondary supervisor. Here I'm referring to "primary" supervisor as the one who actually takes on the bulk of the responsibility, and "secondary" supervisor as anyone else on the supervisory team, regardless of their official designation.
Answer: You want to lighten the load of the primary supervisor, which they will probably appreciate. You could make a list of the things that the primary supervisor does. Then from this list, guesstimate which ones take up most of the time of the supervisor and of those, indicate which ones you want to (and are able to) help out with or just take over, eliminate the rest. From the remaining tasks, pick those that stand out in terms of helpfulness for both you and the primary. Propose to the primary supervisor that you want to take over these tasks and explain how you want to do it, and make a plan together to execute this.


vim struggles when copy-pasting large blocks of text in from an external window

Question: I select and copy a large block of plain text from some file (e.g. gedit).  I run :set paste and then enter insert mode, and paste the text in using the right mouse-button menu.  vim them uses 100% cpu for the next several minutes before successfully pasting my text in.  The text is usually only a few pages, and takes less than a second to paste into other applications (gedit window, web window, etc).  What is vim doing with all those clock cycles and how can I make this more efficient?
Answer: Based on a suggestion from the maintainer after filing a bug report, it seems this problem is caused by the syntax highlighter.  Disabling syntax highlighting temporarily (:set syntax=off) fixes this, though having to do both that and :set paste, and then toggle each back again is rather annoying (yes, I know I could map the commands in .vimrc.  It is still annoying).   Pasting also runs faster in gvim than in vim.  Not sure why.
So, current answer is "turn off syntax highlighting"...
Comment: Who is then that cboettig that wrote: So, current answer is "turn off syntax highlighting"... :-). I'm being sarcastic of course but don't get me wrong, I'm just noting the contradiction. Anyway after investigating a bit more I thing that the evilsoup's answer is even more to the point. See also http://stackoverflow.com/questions/18258561/pasting-a-huge-amount-of-text-into-vim-is-slow
Comment: Why don't you mark this as the correct answer?
Comment: Because I feel that Jim's answer is correct, this is a bug.  There's no reason one should need to turn syntax highlighting off for a simple copy-paste to work smoothly like it does in gedit, etc.  Just seems that the bug depends on the syntax highlighter extension, not base vim.
Comment: This may also be caused by `foldexpr`. When I'm pasting into markdown, just disabling syntax doesn't help. I've documented a fix in this answer: https://stackoverflow.com/a/61694190/3407728
Answer: The correct way to paste text in vim is with the p command (from normal mode).
To paste from the xclipboard (the 'middle-click' clipboard), you should use "*p. To paste from the Ctrl+v clipbaord, use "+p.
Comment: ...Unless your vim doesn't support `"+`, like the Mac default version. (:
Answer: You should probably file a bug report against vim on this one.
Comment: okay, thanks.  I've posted my bug to email@example.com as suggested here: http://vimdoc.sourceforge.net/htmldoc/intro.html, we'll see if anything happens.


Hydrogen Ions — Common, right?

Question: The Wikipedia entry for Ion states "A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle-free space."  Cells pumping ions across membranes is very common so can someone help me understand what context might be implied by the quote?
Comment: It's not clear what you mean by "*what context might be implied by the quote*". What specifically are you asking about?
Comment: Welcome to Biology.SE! This appears to be a chemistry question and is almost certainly answered on [Chemistry.SE]. The short answer is that aqueous H+ is actually H3O+. Please take the [tour] and then go through the [help] pages starting with [Ask] questions effectively on this site. Note in particular the section on ["homework"](https://biology.stackexchange.com/help/homework) questions. Thanks!
Answer: I'm still not entirely sure what specifically you're asking about, but I have a guess. It is true that positively-charged hydrogen ions, or bare protons, are typically only observed in gaseous/plasma states and hard vacuums, and it is also true that cells routinely pump positively-charged hydrogen ions across membranes. This is not a paradox because in aqueous solutions, hydrogen ions exist as $H_3O^+$, also known as hydronium or hydroxonium.

Image from Wikimedia Commons
Answer: You are on the right track with your thinking about the paradox of an actual proton being pumped across the membrane, and it's just a problem of how the chemistry is communicated. The protons actually move along what is called the proton channel, which essentially is a row of protonated amino acids like glutamate (glutamic acid) or histidine.
If we think about complex 1 in mitochondria (below), when a proton in the matrix is "pumped" across, it actually "pushes" protons down the proton channel into the matrix (See the light blue line in the figure below). Think of a series of train cars on a track getting pushed.
Finding these proton channels and figuring out how they work is actually a very competitive field. Since they are buried in the membrane, they are challenging to work with, and we don't know much about them.

Even as someone who works in the field, I have to remind myself that all chemistry works this way. If it is water, protons, or electrons, talking about a single molecule is the wrong way of thinking about it.
Citation for Figure https://www.nature.com/articles/s41467-020-17957-0
Comment: "talking about a single molecule is the wrong way of thinking about it" super helpful

Hydrogen Ions — Common, right?


See/compute long-term network stats in Ubuntu (e.g. how many megabytes downloaded during last month)

Question: On Ubuntu, I'd like to know how many megabytes have come in (download) or gone out (upload) of my computer via the network in the last month, or week or whatever (the longer the better). Is there any place where I can see this kind of statistics? Or, is there any log file where for example every connection gets logged with the total amount of bytes sent and received, so that I could do a little bit of grepping of those log files and compute a sum?
Comment: [This](http://stackoverflow.com/questions/199432/i-need-a-tool-to-log-linux-network-traffic-by-ip-address) question might be relevant.
Answer: Many useful commands below:
http://www.cyberciti.biz/faq/network-statistics-tools-rhel-centos-debian-linux/
e.g. I used ifconfig ppp0 to find bytes being transferred on the broadband dongle which gets named ppp0 when connected on my ubuntu 12.04.  If I disconnect and reconnect, it will give the fresh number of bytes transferred on next invocation so I can know whether the total data transfer is within limits.
Note that I haven't found a way yet to find number of bytes transferred last month/week etc but if I remember my last search on same subject there probably isn't any tool available like that.  So you may have to write your own script of some kind which collects such data and saves it in a log or database for later summing up.
Comment: Perhaps the statistics collected by sysstat help?


How do internet speed optimizers work (if they do at all)?

Question: Are applications that claim to improve web speeds effective? If so, how? I would have guessed they were scammy, but I suppose if they can reroute traffic to a closer datacenter it might be possible?
Answer: I wouldn't call them scammy, but, they are far from perfect and when I last looked in to this sector, it is a complete waste of time for the majority of people.
Datacenter location has a part to play, but, it is more than that (remember, if you access a page, the caching server still has to get it from the source server - if anything, it adds another step!).
The main way it works is through compression - on a dial up modem / similar old connection, it can really improve everyday browsing speeds.
Answer: It depends of how you define web speeds. And what exactly do you expect to speed up. Here are a couple of aspects:

a caching http proxy will make sites load faster if you visit them often and if they have static content. It'll be slower once, when the proxy will fetch stuff into its cache, as William Hilsum pointed, but then cached content will load faster (until the cache entries will expire and the proxy will request them again). squid is a good example of http caching proxy.
a filtering proxy will make sites load faster by not loading misc ads and banners. There's a big difference between loading things and not showing them (like certain browser plugins do) and not loading unwanted things at all. privoxy and polipo are good examples of filtering proxies
a caching DNS server. There still are unfortunate cases when ISPs neglect the performance of their DNS servers - in the evening everybody gets home and starts surfing the net. And... it looks horriby slow because of those slow DNS queries. Of course, there are workarounds like using OpenDNS (and these workarounds have their own drawbacks, like redirects to ads etc). But having a local caching DNS server under your own control is good. pdnsd is a good choice.
Answer: A good many 'web optimisers'  are proxies which compress images - opera turbo is an example, and netbooster (which came with my dad's indian wireless internet dongle) seems to work the same way. Its a trade off between quality and speed.


How to cheaply fix crooked looking tile?

Question: Is there any way of making the tiles on the back wall look straight?
Comment: Can you show pics , five feet away. May be able to dado a board. And slides down on high end . Up on the other. And paint it to match ceiling , so you dont see it . Along window.
Comment: Tye tiles are straight the ceiling and wall transition is crooked.
Comment: add another row of tile
Comment: Kris - yes, it is the wall that is at an angle as our roof line widens towards the back. Robert - what is a dado a board? Jsotola- another line of tile would be on the ceiling as it is following the roof line
Answer: Trim baby, trim...
You will need some custom angled molding made to follow the straight lines of the tile joints, but "absorb" the crookedness of the wall in its internal angles. It will not be an easy fix though, it will take a very skilled millworker / cabinetmaker.
Comment: I was thinking trim, the rest of the room around the windows and nooks have a brushed steel trim, do you think it would look weird if the trim was different just in that one place?
Comment: I would not, but I'm a man so my sense of aesthetics is suspect. Just ask my wife...
Answer: If you were willing to replace the top course of tiles, you could swap in a mosaic (either regular or irregular), and the skew would be effectively hidden.
Failing that, get the roof/wall skimmed down to a level line.
Comment: That sounds expensive, we are at the end of the build and have a grand total of zero to spend
Comment: Sorry -- neither of those are super cheap. My last idea is to paint that section of wall almost the same color as the tile.
Answer: Dazzle camouflage
Either re-tile, or re-paint, with some sort of irregular pattern that makes it almost impossible to see the uneven lines.
This will require giving the bathroom "character", and many buyers are not great fans of "character", but it is the most expedient way to mask the error.
And it's hardly new in architecture; things like popcorn ceilings or knockdown drywall are designed to hide flaws in drywalling.
Answer: You mentioned in a reply above that you're currently out of budget, which makes a "total rework" kind of fix out of scope.
What about some "distraction" type of fix? Get a printed peel-and-stick wallpaper with an irregular pattern that distracts from the asymmetry and will be fine for now (for real, or ironically) until in a few years you can't stand it any more but have the $ for a more substantial fix.
Edit: You could apply this to the part above the tile, but also you could apply this to the tile. Whatever "distracts" more and works well with the pattern you choose...


What is the minimum All-Star score(s)?

Question: What are the minimum scores in All-Stars for each difficulty? I want to collect all of the alt trophies, but I want an easy to figure out if I beat All-Star as a character (besides going to the gallery).
Answer: Because the main component of score in all-star mode is damage dealt, there is no theoretical minimum or maximum.
Comment: Is there an average?
Comment: Well yeah, but it's based on how much damage you tend to do before KOing people, so there's no real way anyone but you can figure it out.

What is the minimum All-Star score(s)?


Homogeneous Differential Equations Inspiration

Question: Homogeneous first order differential equations can be solved by substituting $y/x = v$. I was wondering what is the inspiration for this. I am trying to understand the thinking behind this substitution. It is a known property of homogeneous polynomials that they can be expressed as functions of $y/x$, but how could you be sure that once you do that, the variables are separable? Again, the homogeneous polynomials $M$ and $N$ have to be of the same degree, otherwise, they are not separable. What's the thinking behind that? HFODEs are one of simplest
type, so I was wondering if there's an intuitive way one could think about this (or is there any other analytic algebraic property of homogeneous polynomials that I am missing?)
Comment: If a function $f(x, y)$ of TWO variables is homogeneous of order $n$, then it always has a special form $f(x, y) = x^n f(1, y/x)$. That means if I define $g(z) = f(1, z)$, a function of ONE variable, I can write $f(x, y) = x^n g(y/x)$. Very informally speaking, you need less information to describe $f(x, y)$ than a general function with $2$ variables. You only need $g$ (a function with 1 variable) and $n$ (an integer) to describe $f$. So why the substitution $v = y/x$? That's kind of hinted by $f(x, y) = x^n g(y/x)$, isn't it?
Answer: Tunococ, no offense intended, but what you have said is given in any standard textbook on differential equations. As I said earlier, some ideas become clear after you go through with them, and this analysis is precisely that. That's not what I am after.
At this point I should clarify my comment on your answer. When solving a DE, our primary concern is separation of variables. Simplification is a secondary concern. A substitution which transforms our equation into something more complex, but separates the variables is more useful than one which simplifies our DE without separating the variables. As far as simplification is concerned, transforming, $f(x)$ into  $f(y/x)$  and then substituting $y/x = v$ is a logical step (not a natural guess!). But with respect to separation of variables, it is not.
Johann Bernoulli is said to be the first to suggest this method.The following statement is attributed to him "I attempt only to separate the indeterminate $x$ and it's differential $dx$, from the indeterminates $y$ and $dy$, which deserves the prize in this investigation, for otherwise the construction of the solution to the differential equation won't be achieved."
(Ref - A History of Analysis - Hans Niels Jahnke). So there's a strong probability that when JB suggested putting $y/x = v$, he was looking at separation of variables, not simplification of the DE.
Now I am not insisting that he discovered this substitution in a a logical manner. What you suggested could have been true. I am only saying that, if such a possibility exists, we should explore it.
You did raise an important point however, that I overlooked - homogeneous functions need not be polynomials.As for degree not being an integer, that can be changed via substitution.
Comment: Note: as the question owner, you should be able to add comments on the answers given by other users by using the "add comment" link below each individual post. Not only will this help with threading (to guide other readers), it will also notify the answerer of your comment (Tunococ likely had no idea you posted this comment about his/her answer). Please in general avoid using the "answer" field to make comments on other posts. Thanks.
Comment: The 'comment' in the above post, refers to one which I posted earlier (see below - Jan 19 6:32). Yes, I could have posted my earlier 'answers' as comments(because they were really comments on other answers). But I was new to the site, so..... .One of my earlier comments - (Jan 19 2:25 is not appearing in full (why?). I did not want that to happen to this comment, which was intended to clarify what I was looking for.That's why I posted it in the answer field.
Comment: "Not appearing in full": that's because when an comment-posted-as-answer is converted to an actual comment, the character limit is for comments is applied. Your comment-posted-as-answer is just a bit too long. Comments are encouraged to be succinct.
Answer: Ok, here's how I can "be sure that once you do that, the variables are separable".
Suppose we're given a first-order ODE of the form
$$
M(x, y)dx + N(x, y)dy = 0.
$$
If $M$ and $N$ are homogeneous functions of the same order, then
$$
\frac{dy}{dx} = -\frac{M(1, y/x)}{N(1, y/x)} \quad\text{ or }\quad
\frac{dy}{dx} = -\frac{M(x/y, 1)}{N(x/y, 1)}.
$$
You can choose to substitute either $u = y/x$ or $u = x/y$. Say you pick $u = y/x$. Then you substitute $dy = x du + u dx$ back in the equation to get
$$
\frac{x du + u dx}{dx} = f(u)
$$
where $f(u) = -\frac{M(1,u)}{N(1,u)}$ is determined by the previous equation. Rearrange to get
$$
xdu = (u + f(u))dx \quad \Rightarrow \quad \frac{du}{u + f(u)} = \frac{dx}x.
$$
You can now integrate. The solution is
$$
\int^{y/x} \frac{du}{u - \frac{M(1,u)}{N(1,u)}} = \log x.
$$
P.S. Homogeneous functions do not have to be polynomials. The order of a homogeneous function doesn't have to be an integer.
Comment: Tunococ, I appreciate your answering my question, but you are missing the central point of my question. It is true that once you make the substitution y/x = v, you need less information to represent M and N. But in the big picture you are still reducing, a differential equation of two variables - x and y to another differential equation in two variables, x and v. My question was, how do you know that the variables x and v are separable? Now I understand, that in problem solving,(whether in science, engineering or math), some ideas become clear only after you go through with them.But when you s
Comment: @NikhilPanikkar: As Tunococ says, the form $f(x,y)=x^ng(y/x)$ would become $f(x,v)=x^ng(v)$, so you've clearly separated them. Actually getting to this form is perhaps a different question, but one that also comes up elsewhere separately from ODEs, so finding it isn't quite as magical as it might seem.
Comment: Even though Robert's answer is incorrect, I think it has pointed me in the right direction. Consider the equation dy/dx = M(x,y)/N(x,y). Your first attempt will be to factorize M and N such that the equation becomes dy/dx = F1(x)G1(y)/F2(x)G2(y). Now the variables are separable.
Now the question boils down to - when can a function M(x,y), homogeneous or not, can be factorized in to a function of only x and a function of only y? I am stuck here.Somebody help...
Comment: First of all, you should understand that from what I said, the substitution $v = y/x$ is a natural guess. And everything Robert said was correct. Please re-read his last sentence.
Comment: There's a difference between a logical guess and natural guess(understand my question first.)What Robert said was incorrect, try an example where M and N are of different degree.
Comment: Thanks, for replying Robert. But I have to point out - just because two functions can be expressed as factors that doesn't mean that their variables are separable. In the equation we considered, if M and N are of different degree, then the variables are not separable.(just to make it clear, the equation is of the form - $dy/dx = \frac {M(x,y)} {N(x,y)}$ )
Comment: Its related to scalling property of function due to which there are certain conditions here.
Answer: I want to share a small analysis, that I came up with yesterday.
Consider the equation $dy/dx = M(x,y)/N(x,y) - M$, $N$ are homogeneous with same degree.
$dy N(x,y) = dx M(x,y)$ -eq 1
Now let's try separating the variables:
$dy y^n N(x/y) = dx x^n M(y/x)$ - using the property of homogeneous polynomials -eq 2
Now if you look at the above equation, the terms $N(x/y)$ and $M(y/x)$ are the only terms that are not separated. Now if you could reduce them to the same variable, then maybe you might be able to separate them. It must be at this stage that JB might have hit upon the idea of substituting $y = vx$, for then you would be reducing them both to functions of $v$ (Actually on one side you have a function of $1/v$, but for polynomials this can be reduced to a function of $v$. I hope that more knowledgable people will check if this is true for non - polynomial functions.)
So putting $y = vx$
$d(vx) (vx)^n G(v) = dx x^n M(v)$
$= (vdx + xdv) (vx)^n = x^n T(v) dx$
Now if you simplify, you end up with:
$dx/x = -v/ (v^n+1 - T(v))$ .dv
$= F(x) dx = S(v) dv$
where variables have been separated.
Now I am not claiming a great logical approach here (because my algebraic manipulations vary from the conventional approach in a very minute manner), but I would like to point out a major difference - I am trying to separate the variables from the outset, and it is during this process, that I stumble upon the substitution $y = vx$, rather than the conventional approach where, you substitute $y = vx$ to simplify the DE, and stumble upon the separation of variables.
I am not claiming this as a final answer to my question, so please go through my analysis and comment - especially regarding the non - polynomial function case. If anyone can come up with a better analysis, please share.


git fetch not working for fetch new files

Question: I am new to Github and have checked lots of examples for fetching and pulling files from the Git server. However, my fetch command does not work as I expected; my pull command works as I expected and downloads new files onto my system. Is the fetch command not able to download files locally to my branch?
Answer: You need to understand the difference between fetching and pulling.  When you do a fetch:
git fetch

you update all the local tracking branches in your Git folder.  The tracking branches are your local copy of what is actually on the repository, and it is these branches which Git uses for most operations.  This means that every tracking branch will now be in sync with the latest changes from GitHub.  However, this does not mean that the local branch you have is now up to date.  To bring your local branch up to date you have to additionally either merge or rebase that branch on the remote tracking branch.
Assuming you are on the master branch, you can remember what git pull does as follows:
git pull = git fetch + git merge origin/master

In other words, there is merge here to actually get the changes from the remote repository into your local branch.  You could also rebase your local branch on the version in the remote via git pull --rebase master.
So the answer to your question is that the fetch command absolutely does bring in changes from the remote to your system, but you have to additionally merge or rebase to update your local working branch.
Comment: Strange, if i use "git merge origin/master (or my branch)" then it works after fetch but i see in other links "git merge origin master" it is not working.
Comment: `git merge origin master` means merge your local branch into itself.  This doesn't make any sense logically.  `origin/master` is the local version of the remote branch and this is what you want to merge into your local branch.
Comment: Should "When you do a fetch [...] you update all the local tracking branches" instead read, "[...] you update all the remote branches"? See [this answer to a different post](https://stackoverflow.com/a/16408515/3276252) for why I ask.


How do tropopause folds form and do they have any impact on synoptic scale weather?

Question: What is the process that creates a tropopause fold?  Do these features have any significant impact(s) on weather patterns or the atmosphere?
Comment: This one is on my list to take a crack at once I dust off my graduate synoptic class notes.
Answer: I am not not an expert in meteorology, but do study the chemistry involved in these types of events.  My understanding is that the folds in the tropopause generally occur below the front of the jet stream, when the potential vorticity is strong enough to transport stratospheric air down through the tropopause/inversion.
Please see the relevant quote from Q. J. R. Meteorol. Soc. (2004), 130, pp. 1195–1212 doi: 10.1256/qj.03.21
Convective mixing in a tropopause fold
By H. J. REID and G. VAUGHAN∗
Institute of Mathematical and Physical Sciences, University of Wales, Aberystwyth, UK
"Mixing between stratospheric and tropospheric air can occur most readily in deep
intrusions of stratospheric air into the troposphere, such as tropopause folds (Danielsen
1968). They occur because of the ageostrophic circulation at the jet entrance (Hoskins
1982) and coincide with the frontal zone beneath the jet. Deep folds can extend down to
the top of the boundary layer (Browell et al. 1987; Vaughan et al. 1994), while smaller
folds, extending only into the upper troposphere, are ubiquitous around the polar jet
stream (e.g. Vaughan et al. 2001). They also occur beneath the subtropical jet stream
(Gouget et al. 1996), where it has been suggested that mixing between the subtropical
fold and tropospheric air promotes the generation of new aerosol particles (Zahn et al.
2000). Turbulence within folds can result from shear instability beneath the jet (Pepler
et al. 1998; Hartjenstein 2000) or from convection extending up from the boundary
layer (Browning and Reynolds 1994)."
As for synoptic scale weather, I don't think a tropopause fold affects the synoptic scale weather events much, but are rather a part of the weather events.  The downward mixing of stratospheric air will introduce drier air, leading to lower humidity in the general vicinity.  Of course, ozone will be entrained into the tropopause as well, which has air quality implications.  And there are certainly feedbacks in the fold phenomena that will affect heat, radiation, and kinetic patterns... but the synoptic weather in the region is going to be more driven by the jet stream itself rather than a fold that may occur.  A meteorologist, though, might have better information on that.
Comment: tropopause folds do impact the meso scale weather. I will come up with another answer shortly.
Comment: such events are driven by STE - http://earthscience.stackexchange.com/questions/2771/monsoonal-interactions-with-mid-latitude-disturbances/2787#2787. Think of it as a vacuum pump. High PV streams cause the isoentropes to be  sucked upwards (increasing updrafts) and leading to decrease in static stability and increased precipitation. The scale is the issue. High PV streams affect only affect mesoscale events.
Answer: Cross tropopause transport seems to be the main driver : Take a look at this.
Comment: Can you summarize what is in that presentation that supports your answer as well as develop your answer a bit more than a single sentence?  We like our answers to stand on their own even if that link is someday removed.


Defense Grid: more towers or upgrades?

Question: In Defense Grid: The Awakening, is it more cost-efficient to build more towers or upgrade existing ones?
Answer: I asked devs the same question and turned out there is no difference from both cost and damage points of views (except for temporals and commander towers). I upgrade towers that are located in most valuable places (i.e. where aliens pass several times) where space is limited.
Quote from a dev:

The choice is actually entirely up to
  you.
level 1 gun tower - cost 100
level 2 gun tower - cost 200 (total
  paid = 300)
level 3 gun tower - cost 400 (total
  paid = 700)
The damage a level 2 gun tower does is
  exactly 3 times as much as a level 1
  gun tower.  The damage a level 3 gun
  tower is exactly 7 times as much as a
  level 1 gun tower.
Essentially, a single level 3 gun
  tower is equal to seven level 1 gun
  towers.  They do the same total damage
  and the total cost of each are also
  the same.
If you're building a maze, the seven
  towers is probably the better choice.
  If you're limited on space, or you
  have a kill zone setup with a temporal
  tower, then perhaps the full upgraded
  gun tower is the better choice.
It really depends on your playstyle
  and the choices you make for any given
  map.
By the way, the above example is true
  for all towers.  (Except the Temporal
  and Command tower, they're special.)
Comment: usually, when you have enough space, and technically it doesn't matter, mutiple towers give the advantage over a single tower, as they're faster to place and can spread out the damage over multiple targets.
Comment: Upgrades give increased range, don't they?
Answer: I found that upgrading always works better for me than to place a lot of towers
Check out what each upgrade does, it shows how much the damage, rate of fire, and range would be increased when you upgrade; I think it becomes clear when you compare damage vs cost.
A level 3 (red) gun tower for example, is way more powerful than a lot level one (green) ones.
Here's an interesting article on that tower, and some design decisions.
There are challenges where you can only build level 1 towers, play that and experience first hand how the gameplay changes.
Comment: I tend to think that red gun towers are too powerful, many times you can pass the level by spamming them, without caring about other kinds of turrets.
Comment: @Gnoupi: Considering it is not too hard to beat the game with no losses whatsoever, I don't think that's a very good strategy.
Comment: @Gnoupi: you sure there aren't any bullet resistant types in the game? I only have the demo so far (so i can't check) but that seems reasonable. Plus, the other towers do have their niches.
Comment: @RCIX - there are, and you are more effective with correct turrets. But there are several levels in which you can just spam them and win (with some losses, though).
Answer: Although I have not myself played Defense Grid, in every other tower defense game I've played it is much more cost effective to upgrade existing ones.
Comment: Well there is a trade off.  Usually for the first several rounds you build towers incessantly.  Then, you start upgrading.  In my experience two towers of level n are usually better than one tower of level n+1 and only mildly more expensive.  This is especially true of towers that target one creep at a time.
Comment: Depends on how the towers upgrade in the game.  For instance, in Sanctum it's more cost-effective to build more towers than to upgrade existing ones.

Defense Grid: more towers or upgrades?


Completely bounded norm for unital maps with completely positive sections

Question: Consider a completely bounded unital map $\Phi: \mathbf M_h(\mathbb C) \to \mathbf M_k(\mathbb C)$. Suppose that $\Phi$ has right-inverse $\Psi$ which is completely positive. Is the operator norm of $\Phi$ stable under tensor products with other spaces — i.e., is $$\lVert \Phi \rVert \stackrel?= \lVert \Phi \rVert_{\mathrm{cb}} = \bigl\lVert \Phi \otimes \mathrm{id}_{\mathbf A} \bigr\rVert$$ for $\mathbf A = \mathbf M_h(\mathbb C)$?
Comment: Is $\Psi$ also assumed to be unital? (And do you want trace-preserving?)
Comment: @YemonChoi: (a) if $\Psi$ is a right-inverse of a unital map, is it not also ipso facto unital? (b) I am very sure that I do not want to restrict to trace-preserving unital maps --- I have the 'trace' tag only because I'm aware that trace-preservation is the dual property to unitality,  so there is an equivalent version of this question involving trace-preserving maps which may not be unital, and their *left* inverses.
Answer: Unfortunately, the answer is no.
Suppose $\Phi : M_4 \rightarrow M_2$ and $\Psi : M_2 \rightarrow M_4$ are given by
$$\Phi\left(\left[\begin{array}{cc} A & B\\ C& D\end{array}\right]\right) = A + 10B^T \ \ \textrm{and} \ \ \Psi(A) = \left[\begin{array}{cc} A&0\\ 0&A\end{array}\right] $$
where $A,B,C,D\in M_2$. Then $\Phi$ is unital, completely bounded, $\Psi$ is unital, completely positive and $\Phi\circ\Psi = I_{M_2}$ but
$$\|\Phi\| \leq 11 \ \ \textrm{and} \ \ \|\Phi\|_{\rm cb} \geq 20$$
since the transpose map is cb-norm 2.

There is also a negative answer if you look for $\Phi$ being left-invertible by a ucp map:
In this case a counterexample is given by $\Phi : M_2 \rightarrow M_4$ and $\Psi : M_4 \rightarrow M_2$ defined by
$$
\Phi(A) = \left[\begin{array}{cc}A & 0 \\ 0 & A^T\end{array}\right]\ \ \textrm{and} \ \ \Psi\left(\left[\begin{array}{cc} A & B \\ C & D\end{array}\right]\right) = A
$$
where $A,B,C,D \in M_2$. Then $\Phi$ is ucb, $\Psi$ is ucp and $\Psi\circ\Phi = I_{M_2}$ but
$$
\|\Phi\| = 1 < 2 = \|\Phi\|_{\rm cb}.
$$
Comment: This looks like a pretty straightforward example, thanks! It appears that I still am not asking quite the right question, but your answer is helpful in getting me to the right one.


Is a transfer between 2 NRO accounts a taxable event?

Question: I'm an NRI and my friend who is also an NRI wants to transfer money from his NRO account to my NRO account. Does this transfer attract Tax?
Answer: Transfer by itself is not liable for taxation.
But depending on the amount, the Income Tax Department might request clarification from you on the source and reason for the fund transfer.
Additionally, any interest you receive in the account will also attract a TDS deduction.
Answer: There is no tax unless it is an income. Then income tax will apply, and the recipient will need to file ITR.


I can't find the contact after I saved them on my IPhone 5S,

Question: I can't find the contact after I saved them on my IPhone 5S, I have searched for the name after I saved the number but couldn't find it, I don't know how to solve this issue I can't even find it in the Apps like Whats App.. It sounds like the contacts disappear?
Comment: Do you mean a specific contact or the app named `Contacts'?
Answer: Go to Contacts. Upper Left hand corner, tap "Groups". You may have more than one account apart from your iCloud account, like Gmail. In this case, it might be that only one account is checked so just check all accounts including your iCloud account.


What are some options for acquiring a free realtime Linux distribution?

Question: By realtime I mean something that can help with fast network I/O; Low-latency and high-throughput.
Comment: What would lead you to believe that there is an answer to this question that would be useful in any way?  It is highly subjective, and almost certainly too localized.
Comment: Should have been edited to title, "Suggestions for obtaining a free realtime Linux distribution".
Comment: @JohnPristine What is the application for the realtime OS in your case?
Answer: I'd say CentOS or Scientific Linux with a realtime kernel compiled from Red Hat MRG source RPMs or using the CERN pre-built binaries.
See: Compiling realtime kernel from RHEL 6 MRG sources on CentOS 6
and CentOS 5 - realtime patch
The caveat is that simply installing a realtime distro won't automagically make everything faster. These kernels and related tools give you more "knobs" to tweak and ways to measure performance. This can be done for free (I've done it), but you will have to invest the time into working with your application and environment. Using the option I outlined, you can at least start with the RHEL MRG Tuning Guide.
On the tuning side, there's a lot more to work with in this realm. E.g.

Familiarize yourself with Ethtool and its options.
Investigate how interrupts work. E.g. what really happens when a NIC generates an interrupt. What does setting /proc/irq/irq_number/smp_affinity really do?
Understand CPU/process binding and realtime/rtctl priorities.

Other options include the commercial Concurrent RedHawk Linux (RHEL-like) and SuSE Enterprise Realtime. But they are costly distributions.
Comment: The OP asked for a *free* realtime distribution. There are other solutions that can be tweaked and tuned, but they're expensive. I suggested a free path that *can* provide high performance (with the right tuning steps for the environment).
Comment: Do you actually have any data or anything to support your suggestion that CentOS/Scientific/Redhat Linux is the fastest?  Or are you just suggesting it because you are familiar with it?
Comment: That's awesome information! Thank you! I am not an IT guy so not sure I would be able to configure all that. I do understand IRQ, affinity, non-blocking, priorities, core isolation, etc. I wonder if I can buy this service from someone, in other words, if i can pay someone to install and configure a realtime os.
Comment: Yep. There are people who can provide this service. See my profile.
Comment: @ewwhite How do I find your email in your profile?
Comment: Use the Google!


Complex analysis exercise (Mittag-Leffler related)

Question: I'm trying to make an exercise in a complex analysis textbook, but I'm stuck, so I hope someone can help me out. The exercise is assigned in a chapter about the Mittag-Leffler theorem.
1) If $f$ is an holomorphic function on $\mathbb{C}$, with exception of a finite amount of poles and $f$ is bounded by a polynomial for $\vert z \vert \ge R$, then show that $f$ is a rational function.
I think I succeeded in proving this part, by subtracting the singularities from $f$ and using (a modified version) of Liouville theorem. I mention the question because it may be related to the following questions.
2) If $f$:$\mathbb{C}$\ {$z_1$,...,$z_n$} $\rightarrow$$\mathbb{C}$ is injective, continuous and not bounded, then show that $\lim_{z \rightarrow \infty}f^{-1}(z) \in \{z_1,...,z_N,\infty\}$. (Hint: Weierstrass)
3)If $f:\mathbb{C}$\ $\{$$z_1$$,...,$$z_n$$ \}$ $\rightarrow \mathbb{C}$\ $\{$$w_1$$,...,$$w_n$$\}$ is a holomorphic bijection, with $z_1,...,z_n$ poles of $f$, then show that $f$ is a rational function.
I don't really see how to solve 2) and 3).
Answer: For (2) as stated, if $\lim_{n \to \infty} |x_n| =  \infty$, then any convergent subsequence of $[f^{-1}(x_n)]_{n \in N}$ could not converge to anything in $C$\ $\{ z_1,...,z_n \}$ else $f$ would be discontinuous. Were there more conditions on $f$ ?


powershell to get the first x MB of a file

Question: Its pretty straightforward to get the first x lines of a text file, but I need the first x MB of a file.  Given that I'm a PowerShell neophyte if you could please give me some annotations on the script that would be greatly appreciated.
Comment: [This](http://stackoverflow.com/a/18936628/2707864) worked for me. And it does not traverse the whole file as `get-content`, so it is most convenient for large files.
Answer: Get-Content foo.exe -TotalCount 1MB -Encoding byte

If you happen to be using PowerShell Community Extensions then do this:
Format-Hex foo.exe -count 1MB

Note: If you are using PowerShell V2 be sure to grab the 1.2 beta of PSCX.
Answer: Independent of PowerShell, I'd just use the head command. (It's a standard Unix command, but it's available for Windows.) The -c option lets you specify the number of bytes you want.

head -c 1024 foo.exe
Comment: One of the reasons I loath asking powershell questions is the for the obvious "you could do it unix with ...." answers.  there's got to be a dozen of non-powershell ways of getting what I'm looking for, but I"m looking for a powershell answer.
Comment: Maybe someday you don't want to read the first 1 KiB of a file but from a binary registry key. Also, there are ofttimes things you miss in a new technology because you're too accustomed doing it your old-fashioned way. You wouldn't recommend using sed/awk on wmic output to a Powershell user, would you? Also, head (being not a cmdlet) will yield a string[] which may not be what you want.
Comment: It's important to realize that there are often cases where a machine is locked down so that you can't install new software, but you *can* run PowerShell.  That's a good use-case for "want  PowerShell, can't use X ported unix executable"
Comment: And I don't understand why anyone would restrict solutions to PowerShell when there are solutions that work everywhere, not just PowerShell. I mean, unless it's just idle curiosity: "Gee, I wonder if I can do that in PowerShell." You didn't say it needed to be a PowerShell-only solution. I figured you're just sitting at a PS prompt and wondering how to get the first N bytes of a file. The answer is the same as if you were sitting at any other prompt, and it's not a Unix solution, either.


Is faceless rudraksha powerful than all faced ones?

Question: I currently have Panchamukhi Rudraksha. Is nirakara (faceless) Rudraksha more powerful than all faced ones? According to
http://www.shivamrudraksha.com/face-less-rudraksha-with-om-mark.php
Comment: This question is not about Yoga, Tantra etc.. Only Rudraksha is the correct tag. You may remove the other tags you added.
Comment: @Rickross Well, you could have done that in your edit since you also have editing privileges?
Comment: @Aoi.T_015 please don't decide these things without proper consultation. Wearing wrong kind of Rudraksha may not be good. 5 mukhi is normally good for everyone. Sadhguru says Ekmukhi should not be worn by householders. So take care. https://isha.sadhguru.org/in/en/wisdom/article/the-significance-of-rudraksh
Comment: And also refer this FAQ https://www.ishashoppe.com/in/the-rudraksha-guide
Answer: Different Mukhi beads ranging from zero to twenty-one faces are also occasionally available. Each Mukhi is used for a different purpose, and better being aware of all their different qualities. Wearing the wrong type could disturb one's life.

Answer to your question in simple words each has its own power but to
  be consider power full The Eighteen Mukhi Rudraksha is a rare
  one and is the most powerful bead for prosperity. This is our Mother
  Earth' Rudraksha. Wearing her bead, you will acquire immense wealth.

All Rudraksha Information provided below:

According to rudrakshanepal.com

The faceless rudraksha(nirakara) - the one without line - round and perfect with a natural hole befits its name of Nirankar Rudraksha.
The wearer feels complete and whole and the wearers charisma increases day by day making people more receptive and acceptive to the wearer naturally.
    Nirankar Rudaksha works on improving personal confidence and self-worth, removes any resistance, anger, insecurities one has with people thus improving relationships on all levels. Improves and structures thought patterns so that one has clear, structured positive thinking.
Removes any worries from the mind on wealth and relationships. Beneficial for stock-traders, lawyers, bankers, teachers or in those in professions where confidence, charisma, stability and long term business or people to people relationship is required

The One Mukhi Rudraksha
Symbolizes Lord Shiva. This is the supreme Rudraksha for anyone who want to get connected to the Supreme power. It destroys all sins and allows you to liberate yourself. On a physical point of view, this kind of bead cures migraines and diseases from the brain.
The Two Mukhi Rudraksha
Represents the combination of Lord Shiva and Goddess Parvati. It blesses the wearer with harmony and unity. This type of Rudraksha cure emotional weaknesses. It helps to wearer to release fear and find inner happiness.
 The Three Mukhi Rudraksha
Frees the wearer from his past birth Karma, releasing past memories of anger, and any kind of feeling associated to low self estime. It allows you to shine and reveal your truth.
Four Mukhi Rudraksha
Associated to Lord Brahma, the creator of the Universe and the representation of knowledge and creativity. Wearing this Rudraksha your power of concentration, of knowledge and creativty will increase.
Five Mukhi Rudraksha
Are the most common type of Rudraksha. It is safe and good for everyone – man, woman and child (up to 12 years old). This is the Rudraksha type we mostly use. The 5 Mukhi Rudraksha is used for general wellbeing, health and freedom. It enhance awareness, destroying the bad karma of the present life and helps those who whish to discover their higher-selves.
Six Mukhi Rudraksha
Makes the wearer more connected to Motrher Earth. It gives you stability and increases your stability and grounded feeling.
Seven Mukhi Rudraksha
Represents the Goddess of wealth, Goddess Mahalaxmi. It promotes good physical health, wealth and abundance.
Eight Mukhi Rudraksha
Is associated to Goddess Ganesha, the remover of obstacles. It will help you to gain confidence and achieve success easily, leading to a happier life.
Nine Mukhi Rudraksha
Is the representation of Goddess Durga, the female form of the Supreme Being. It will protect you from all sufferings and remove your misery. It is the symbol of freedom, freedom from fear, in order to live a life of success.
Ten Mukhi Rudraksha
Is known to be the most powerful Rudraksha, being able to pacify all the nine planets. It is a strong protector against negative energies and Evil.
Eleven Mukhi Rudraksha
Is associatied to Lord Hanuman who represents courage, bravery and adventure. It gives the wearer courage and fearless power.
Twelve Mukhi Rudraksha
Represents our Lord Sun. It allows you to shine, to be radiant and powerful. It helps you to release all tensions, as stress, doubt, worry. It blesses you, give you self-confidence and motivation in your life.
Thirteen Mukhi Rudraksha
Is a very rare piece that gives the wearer wealth, a divine charisma and an immense power. Helping you to lead a happy and satisfactory life.
Fourteen Mukhi Rudraksha (or Dev Mani)
Is one of the most precious Rudraksha. It is said that it has came directly from the eyes of Lord Shiva, who was wearing this bead. It activates your Third Eye Chakra, giving you the ability to visualize things clearly and stimulating your spiritual capacities.
Fifteen Mukhi Rudraksha
Is known to heal the Heart Chakra. Any discomfort related to the heart will disappear.
Sixteen Mukhi Rudraksha
Protects you and releases all kind of fear and insecurity. It liberates you from the fear of death and cures diseases. It is a strong protector against negative energies. It will allow you to rise in victory and grace.
Seventeen Mukhi Rudraksha
Allows the wearer to live with great power and divine magnetism. It is associated to Vishakarma, the builder of the Universe. The wearer of this kind of Rudraksha bead, is filled with abundance.
Eighteen Mukhi Rudraksha
Is a rare one and is the most powerful bead for prosperity. This is our Mother Earth' Rudraksha. Wearing her bead, you will acquire immense wealth.
Nineteen Mukhi Rudraksha
Creates satisfaction within you. This bead will help you to attract all what you want, in business, in love and in life in general
Twenty Mukhi Rudraksha
Is ruled by Lord Brahma, the creator of the Universe. This Rudraksha bead stimulates the knowledge and intellect of its wearer. It gives you strong power and fulfilment of desires.
Twenty one Mukhi Rudraksha
Is the rarest Rudraksha bead, allowing the wearer to be blessed in all points of view. It is a very strong protector.
Gauri Shankar
Two beads that have grown and joined together naturally symbolize the holy union of Lord Shiva and Goddess Parvati represented by the Soul and the Mind. The Gauri Shankar Rudraksha is rarely found and blesses the wearer with the gifts of awakening of Inner consciousness, spiritual evolution and oneness with people and elements. It evokes pure universal love. It is known to improve relationships, bring joy and harmony. The Gauri is an extremely influential and powerful Rudraksha that is recommended for meditation.
There is news recently that a 27 mukhi rudraksha have found in indonesia and nepal.

you can go through rudraksha-ratna.com also where each rudraksha is explained well with images to understand.
  And also got through "aumrudraksha.com"

And also I am collecting all new data on rudraksha that are recently found the information is very hard to find
Comment: Welcome to Hinduism Stack Exchange. It looks like you have copied information from other websites. You didn't put that information in quotes. What you wrote is put in block quotes. You formatted in a reverse way The copied information should be written in block quotes and the website or a source you are copying should be mentioned properly instead of "this website". See [How to reference material written by others](https://hinduism.stackexchange.com/help/referencing). Also look at [The Copy paste issue - Hinduism version](https://hinduism.meta.stackexchange.com/q/48/5212)
Comment: Some content appears copied from [this site](https://www.aumrudraksha.com/pages/rudraksha-power). It's ok to copy but you need to put them in blockquotes and leave a link/credit the author/website. See [How to reference material written by others?](https://hinduism.stackexchange.com/help/referencing).
Comment: @sv. I have Added reference link that I used. Thanks for the update.
Comment: @Sarvabhouma I have edited my answer as described in the link you provided if you fill I am missing something edit or tell me ill do it right away thanks!! :-)
Comment: Oh! You removed information from your answer but that was not needed. It is enough if you give proper attribution for what you have written. Even if it is not copied and you have paraphrased, that is okay. The details about one mukhi Rudraksha, two mukhi rudraksha etc., you have provided were good. The answer was better with that detail. Why did you remove information collected from [aumrudrakha.com](https://www.aumrudraksha.com/blogs/aumrudraksha/understand-more-about-rudraksha-the-different-mukhi-and-their-meaning)? You can quote that website if that can be relied upon.
Comment: ok ill add it again no worry. but the content is good write.
Answer: In the Devi Bhagwat Puran in the section on greatness of Rudraksha beads Shiva Himself narrates to his son Kartikeya the importance of different types of Rudraksha and states:

O Kārtikeya! As many faces as there are in the Rudrākṣam, for so many thousand Yugas the holder resides with honour in the Śiva Loka. One should declare the greatness of Rudrākṣam to one's own disciple; never to disclose its glories to one who is not a disciple nor a devotee of Rudrākṣam nor to him who is an illiterate brute. Be he a Bhakta or not a Bhakta, be be low or very low, if he holds Rudrākṣam then he is freed from all sins. No equal can be to the merit of him who holds the Rudrākṣams.

We can also understand the relative importance of the different faced beads from the section below:

One faced Rudrākṣa seed is the Śiva Himself, made manifest and rendered vivid; even the sin iñcurred in killing a Brāhmaṇa is destroyed thereby.

Two faced or two headed Rudrākṣam is like the Deva and the Devī. Two sorts of sins are destroyed thereby.

The three faced Rudrākṣam is like fire; the sin iñcurred in killing a woman is destroyed in a moment.

The four faced Rudrākṣa seed is like Brahmā and removes the sin of killing persons.

The five faced Rudrākṣam is verily an image of Rudra; all sorts of sins, e.g., eating prohibited food, going to the ungoables, etc., are destroyed thereby.

The six faced Rudrākṣam is Kārtikeya. It is to be worn on the right hand. One becomes freed of the Brahmāhatyā sin. There is no manner of doubt in this.

The seven faced Rudrākṣam is named Ananga. Holding this frees one from the sin of stealing gold, etc., O Mahāsena!

The eight faced Rudrākṣa is Vināyaka. Holding this frees one from the sin of holding an illicit contact with a woman of a bad family and with the wife of one's Guru, etc., and other sins as well. It enables one to acquire heaps of food, cotton, and gold; and in the end the Highest Place is attained.

The fruit of holding the eight faced Rudrākṣa seed has been said. Now I will talk of the nine-faced Rudrākṣam. It is verily the Bhairava made manifest. On the left hand it should be worn. By this, the people get both Bhoga (enjoyment) and Mokṣa (liberation) and they become powerful like Me and get themselves freed at once, without the least delay, of the sins iñcurred by committing thousands of abortions, hundreds of Brahmāhattyās (killing the Brāhmaṇas).

Holding the ten-faced Rudrākṣa is verily wearing Janārdana, the Deva of the Devas. The holding of which pacifies the evils caused by planets, Piśācas, Vetālas, Brahmā Rākṣasas, and Pannagas.

The eleven-faced Rudrākṣam is like the Eleven Rudras. The fruits, the efficacy of which I now describe. Hear. The fruits obtained through the performance of one thousand horse sacrifices, one hundred Vājapeya sacrifices, and making gifts of one hundred thousand cows are obtained thereby.

If one wears the twelve-headed Rudrākṣam on one's ear, the Ādityas get satisfied. The fruits of performing Gomedha and Aśvamedha sacrifices are obtained thereby. No fear comes from burned buffaloes, armed enemies and wolves and tigers and other murderous animals. Also the several diseases of the body never come to him. The holder of the twelve-faced Rudrākṣa seed feels always happy and he is the master of some kingdoms He becomes freed of the sins iñcurred in killing elephants, horses, deer, cats, snakes, mice, frogs, asses, foxes and various other animals.

O Child! The thirteen faced Rudrākṣam is very rare; if anybody gets it, he becomes like Kārti Keya and gets all desires fulfilled; and the eight siddhis are under his grasp. He learns how to make gold, silver and other metals; he attains all sorts of enjoyments. There is no manner of doubt in this. O Saḍānana!If anybody holds the thirteen faced Rudrākṣam, he becomes freed from the sins iñcurred in killing mother, father and brothers.

O Son! If one holds on one's head the fourteen faced Rudrākṣam always, one becomes like Śiva. O Muni! What more shall I speak to you! The Devas pay their respects to one holding the fourteen faced Rudrākṣas and he in the end attains the Highest Goal, the state of Śiva. His body becomes verily the body of Śiva.

It appears from the above references that the higher the number of faces, more is the spiritual value of the Rudraksha bead, and hence the one with fourteen faces would be the most powerful one based on this text instead of a single-faced one.


Disable udev renaming for Android USB tethering using randon MACs

Question: I have 4G failover via an old Android phone plugged in to USB.
This was working find as interface usb0.
Since upgrading to Debian 12 the device gets renamed to something completely random, and different every time it is plugged in. This fucks up /etc/network/interfaces and my iptables script.
# grep -a renamed  /var/log/syslog
2023-06-27T11:30:09.891759+01:00 calleva kernel: [    1.117331] r8169 0000:02:00.0 enp2s0: renamed from eth0
2023-06-27T11:30:09.891773+01:00 calleva kernel: [    1.144188] r8169 0000:03:00.0 enp3s0: renamed from eth1
2023-06-27T11:30:09.891903+01:00 calleva kernel: [    2.997299] rndis_host 2-1.6:1.0 enx720b8e586e43: renamed from usb0
2023-06-27T11:30:09.892058+01:00 calleva kernel: [    5.010330] rt2800pci 0000:01:00.0 wlp1s0: renamed from wlan0
2023-06-27T11:30:09.892071+01:00 calleva kernel: [    5.325336] rtl8192cu 1-1.4:1.0 wlx08beac0a6c1d: renamed from wlan0
2023-06-27T12:27:13.975350+01:00 calleva kernel: [ 3429.810797] rndis_host 2-1.6:1.0 enx9657a45d9349: renamed from usb0
2023-06-29T22:24:16.219329+01:00 calleva kernel: [212048.668218] rndis_host 2-1.6:1.0 enx5edf49046a6d: renamed from usb0
2023-06-29T22:27:16.975407+01:00 calleva kernel: [212229.420430] rndis_host 2-1.6:1.0 enxea7010e4b5e5: renamed from usb0
2023-06-29T22:53:13.186625+01:00 calleva kernel: [213785.614002] rndis_host 2-1.6:1.0 enx76f12e43a7a6: renamed from usb0

I believe that there are two problems

something called udev is renaming things, and
the Android phone is generating random MACs becauase 'security' bollocks.

There are no settings available on the phone. Therefore: how can this udev nonsense be stopped?
While I'm at it: I noticed that, after editing /etc/network/interfaces and ifup the interface goes to UNKNOWN rather than UP. What's going on?!
enx76f12e43a7a6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000

Tried adding
SUBSYSTEM=="net", ACTION=="add", ATTRS{product}=="XT1700", NAME="hp"

to a new file in `/etc/udev/rules.d
Answer: Moved the file containing
SUBSYSTEM=="net", ACTION=="add", ATTRS{product}=="XT1700", NAME="hp"

from /etc/udev/rules.d/hp to /etc/udev/rules.d/99-persistent-net.rules.
(I suspect that if the file has a 'wrong' name then it doesn't work -- fuck knows.)
Ran
# udevadm control --reload-rules
# udevadm trigger

and re-plugged the device and now the interface is called hp and this seems to be stable.


Do pip and easy_install download Python packages securely?

Question: For example, do they check a digital signature (like apt-get and Windows Update) or can they be required to use SSL? If not, I'm a bit concerned that the downloaded packages could be trojaned..
Comment: Seriously? Your updating tools could be trojaned, the repository could have been hacked or the Python package itself might have a backdoor in it. If you are that concerned about somebody poisoning your downloads, you should install the packages yourself (doing the hash computation on pen and paper just to be sure, of course!). Put simply, I think you are luring yourself into a false sense of security if you think digital signatures are the ultimate answer to viruses.
Comment: @Thomas They can prevent a lot of potential damage when repositories are infected, though.
Comment: Sure, digital signatures won't protect against a backdoor in the package. They would defend against DNS spoofing and hijacking though. And a way to put backdoors into packages is to hack developer machines, e.g. with a trojaned package ;)
Answer: Pip has been updated:

SSL Certificate Verification
Starting with v1.3, pip provides SSL certificate verification over
https, to prevent man-in-the-middle attacks against PyPI downloads.

Version 8.0 also has the functionality to check against local hashes.
Answer: All Python packages are not hosted on pypi.python.org, but easy_install will look the PyPi page for download links. Many common packages like PIL and lxml use their own distribution server (which in fact often causes issues for package consumers). Example: http://pypi.python.org/pypi/PIL/
pypi.python.org itself does not seem to offer HTTPS support of any kind.
If you wish to provide secure easy_install / pip environment I suggest you mirror required packages to a server where you maintain HTTPS yourself and then restrict downloads to this server using <code>--allow-hosts</code> option:
http://packages.python.org/distribute/easy_install.html#restricting-downloads-with-allow-hosts
Comment: Hmmm.. as I feared the safeguards for python developer security are pretty pitiful. Thanks for that tip - imho it's a step forward for some - but I've just got one laptop, and the challenge is mirroring securely. Currently I'm thinking that the most secure way is to check out the projects VCS repository..
Comment: Please see the answer below, this answer is outdated.
Answer:
Where available, MD5 information should be added to download URLs by appending a fragment identifier of the form #md5=..., where ... is the 32-character hex MD5 digest. EasyInstall will verify that the downloaded file's MD5 digest matches the given value.

http://packages.python.org/distribute/easy_install.html
It seems easy_install does some validation, but it seems it only checks if the package repository supplies the MD5 key.
The future plans section of the same page further hilights this:

Future plans:
  - Signature checking? SSL? Ability to suppress PyPI search?
Comment: No. It seems it is generated by the repository, and as such only has meaning for the integrity of the download, not for checking malicious code.
Comment: but is the MD5 key downloaded from the repository securely?


Forex: Where does the order book come from?

Question: For stocks, which I am familiar with, some stock brokers provide access to level 2 data from NYSE and NASDAQ. Level 2 data is also available for some OTC stocks. I am now exploring the foreign exchange market, and I tried to look for "level 2 data for forex", but I am confused:
Some foreign exchange brokers provide real-time access to the order book (depth of market), showing every bid price, bid quantity, ask price, and ask quantity placed by market participants.
From my understanding, foreign exchange is also traded over-the-counter. Many trading locations exist, and the forex broker executes the trade on one of these trading locations.
The questions are:

What exactly does the order book show? Presumably, it does not show the bid and asks of every market participant on the planet because (a) there are lots of trading locations, so it is infeasible for the broker to have a live feed to all of them (b) over-the-counter trading means that there are large transactions that happen without transparency.

Does the order book show bid/ask of the broker's clients only (i.e. bid/asks within the broker's walls)?
Or does it show the bid/ask of all participants in the trading location that the broker happens to use to execute trades?

Where do brokers execute the bids and asks that successfully fill on the order book?
If the broker is allowed to manipulate the order book (e.g. by having the power to fill it with fake data), what is to stop it from front-running its clients?
Answer: Retail forex brokers generally lay-off their order imbalance to large banks that make an institutional forex system. So retail forex is based on an institutional forex banking system.


What are some popular DSLs?

Question: I'm looking for popular domain specific languages. I believe CSS is one and XML/HTML could possibly fall into one? (Although that seems more data than language). The only other one i can come up with is the starcraft map editor...
What are some popular domain specific languages?
Comment: SQL?  INI files?  Markdown?  Half of Ruby?
Comment: `something`: does it exist something less specific than XML?
Comment: Regular expression is one of best examples of DSL
Answer: The trick about domain-specific languages is that you define your own language for your specific problem domain. Or, as stated by Kerzhner (2009) "A DSL is a language that is tailored to describe a particular problem domain." [1]
From that perspective, HTML is a bad example because only few people defined HTML for there problem domain but much more people use it as a standard language for designing websites.
Hence, the question could be also: Are there popular languages to define DSLs? These are languages to define other languages, i.e. metalanguages. I would consider the languages around the Eclipse-Modeling Framework (EMF), OMG's Meta-Object-Facility as the two most common ones. However, GrGen's metamodeling capabilities are also quite impressing and probably easier to learn.
Btw: At Soley, we are building software for developing domain-specific languages. Soley Studio is an integrated development environment for defining graph-based, domain-specific languages that can be used for modeling as well as data analytics.

[1]: Kerzhner, A. A., & Paredis, C. J. J. (2009). Using Domain Specific Languages to Capture Design Synthesis Knowledge for Model-Based Systems Engineering. ASME 2009 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2009. San Diego, USA.
Answer: SuperCollider, or specifically the SuperCollider client (sclang), is considered a DSL used for real-time audio synthesis and algorithmic composition. Additionally, there are other client-side implementations, including ScalaCollider and Overtone, which use Scala and Clojure (respectively) to talk to the SuperCollider server.
Answer: From Wikipedia:

Examples of domain-specific languages include

HTML,
Logo for children,
Verilog and VHDL hardware description languages,
Mata for matrix programming,
Mathematica and Maxima for symbolic mathematics,
spreadsheet formulas and macros,
SQL for relational database queries,
YACC grammars for creating parsers,
regular expressions for specifying lexers,
the Generic Eclipse Modeling System for creating diagramming languages,
Csound for sound and music synthesis,
and the input languages of GraphViz and GrGen, software packages used for graph layout and graph rewriting.

What are some popular DSLs?


How to get  the eglibc source code used by Ubuntu?

Question: How do I get the source code for eglibc in a format that will allow stepping through the source with gdb?
I have tried using apt-get source libc6-dev and that works for getting the source code, but I think that since the pre-processor directives were not applied that the line numbers that gdb has does not match with the source I downloaded. This makes it less useful when trying to step through the source and look at how functions in libc are working.
Answer: If you really want to step through the source I'd recommend building a libc without optimisation and without stripping the binaries.
Fortunately, that should be easy - since you've already got the source, you can build packages from it.  You'll want to ensure the DEB_BUILD_OPTIONS evnironment variable contains noopt to get -O0 binaries and nostrip to keep the debugging symbols, and then build as normal with debuild:
sudo apt-get build-dep libc6
DEB_BUILD_OPTIONS="noopt nostrip" debuild -us -uc

will build you packages built with -O0 and without the debugging symbols stripped; you can then install them with dpkg and gdb will pick up the debugging symbols.  As an added bonus, gdb will also know where to find the source files, so you'll get source listings.
Since we haven't changed the version of the packages, the next time you run an upgrade apt will replace these locally-installed packages with the archive versions.
Answer: You can try apt-get source -d libc6-dev and this should give you the source and the diff in deb format. Then you can uncompress it and it should give the sources in tar.gz uncompress this as well.It should be stored in the directory that you ran the apt-get command in.


Can I set Calendar default reminder to "none"?

Question: This question has been asked recently, and the answer was "Menu->More->Settings->Default Reminder Time". On my Galaxy S II running 2.3 there is no "More" on the Calendar Menu. There is a "Settings" which allows the Default View to be set but no Default Reminder Time. Under Notification settings is the option to Set alerts and notifications, but that is simply the choice between alert and status bar. Like the previous poster I set most of the entries via the web and it is extremely frustrating to have every one appearing on the phone with a 10 minute notification set.
Answer: I have a Nexus S running 2.3 and when I go to Calendar -> Menu -> More -> Settings, I see this screen.  If you click the Default reminder time you have the option of None.
Comment: Interesting - it confirms that the earlier answer was correct for some phones. Mine, however, has only the other three options. The "Default reminder time " is missing.


Buy on Apple online store in US with an Argentina issued debit card

Question: My partner is now in the US and offered to bring me a new phone. Due to COVID restrictions she can't buy it in store, I have to order it in the online store so she can pickup later. My card is being rejected saying "payment authorization failed", my guess is because I'm not able to select billing address in Argentina to match the address of my card (only a handful of countries are available in the selection list). Is there any way around this restriction? All my cards, debit or credit are of course issued in Arg.
Comment: Note sometimes the merchant simply does not want to take the risk with particular orders, often overseas credit purchase or shipping/billing addresses not matching are situations where fraud prevention measures might be triggered. In that case you can do little other than find another merchant or try another card.
Comment: Most address-based verification systems are quite crude, and the ZIP/Postal code matching may be enough. In many countries address verification is not even possible, try selecting France for instance. Different cards may have different checks. Do you have 3D Secure enabled on your card(s)? Also, have you tried using Paypal?
Comment: I did try with PayPal, the order went through but then they canceled it because "unable to secure payment". I'll try with other countries, that's a great suggestion! I have no idea what is a 3D Secure card, I googled it and never seen that here. Thank you for your input!!
Comment: So I tried every single country in the Apple website and none passed, they either say to enter a valid ZIP/Post code or give me the same error. Anything else I can try?
Comment: 3D Secure is a way to authenticate the owner of the card. It is known as Verified by Visa, MasterCard SecureCode, American Express SafeKey, etc. When you shop online, after entering your card details, you are sent to the website of your card issuer which makes additional checks, usually either a password, or a code sent via SMS or e-mail, or validation through an app. Some merchants will only allow payments which they can verify through 3D Secure. When you tried Paypal, who cancelled it? Apple or Paypal? Do you have a Paypal account? What funding source do you have on the Paypal account?
Comment: Turns out it's Apple's fault, we called them and they said no credit or debit cards issued from my country are allowed to make a payment on their website. But they also told her of a few stores that will allow in-store purchase so she will be able to purchase physically. Thank you all for your input!
Answer: TLDR: Call your bank, they're likely the source of the decline.
As an online merchant, I have specific experience with investigating declines, mostly when users complain that they cannot pay me for the (digital) good they want to buy. They have always been from outside the U.S., but not always developing countries - one was from the U.K. It would help if you could get the decline code from Apple. The one that I always ran into was 2046. From my payment processor, when I squeezed them for answers:

This is a generic decline that states, "The customer's bank is
unwilling to accept the transaction. For credit/debit card
transactions, the customer will need to contact their bank for more
details regarding this generic decline." While a bit vague, it is
important to note that this decline response is coming directly from
the customer's card-issuing bank and not due to an error with your
(payment processor) account. Unfortunately, we have little insight as
to why a transaction was declined outside of these decline codes.
The most common reasons for declines are:
Incorrect credit card number or expiration date,
Insufficient funds,
The bank declined based on location,
The bank's fraud rules blocked the transaction
Since banks typically do not share specific decline information with
anyone but their customers, I recommend you have the customer reach
out to the Tier II Technical Support team at their bank, as the
frontline agents may not have access to the necessary tools for
further insight.

Since Apple phones have high value-density and are highly sought-after in developing countries, it could be that the banks are blocking all Apple transactions if they are not first approved. (Particularly in Argentina, based on the things I've read about iPhones-in-the-socks smugglers vs. the Tierra del Fuego authorized Blackberry factory. But that was a long time ago... have they loosened the draconian import laws since then?)
I have never asked my customers to go through the trouble of working their their bank; instead I just give them their order for free so they're happy. Apple probably won't do that for you. So, I don't know how much trouble your bank will give you for letting you make the payment.
Comment: Thank you for all this information! Turns out Apple is not taking any payments from my country at the moment, but she was allowed to walk in a store and buy it in person!
Customs in Argentina never get any easier, we have a limit to how many US dollars we can buy monthly and the little people who can actually travel smuggle as much as possible to resell, sometimes with up to 50% markup on the price! Officially when you travel you are allowed to bring a new phone and a new laptop without any import fees, other than that and you pay 50% of the cost of the product in fees


Alto saxophone fingering for notes written below the staff

Question: I am a beginner on the alto saxophone. I understand the fingering for playing notes on the staff but I do not understand the fingering for playing notes below the staff.  Sometimes there are two extra lines below the five line staff and notes are written on those lines and spaces.  What fingering do I use to get those notes?
Answer: Just one line beneath the stave  I think.  Saxophones go down to a written Bb.  For which the fingering, logically enough, is 'everything closed'.
(Yes, it could be written as A#, which would be two lines below. Not sure why the chart includes lots of enharmonics but not that one.)

Chart from https://www.reedmusic.com/wp-content/uploads/Alto-Tenor-Saxophone-Fingering-Chart1.jpg
Comment: Is the note at two lines below the staff an A# by any chance? I was once a bit confused by a low B# in the pedal line in an organ piece, because the pedals only go down to C.
Comment: Also note that all the notes below the staff (except C Natural) use the keys by your left pinkie.
Answer: Do you have a teacher? Have you tried searching for fingering charts (one such chart is provided as a picture in an answer to this question)? This site is a great resource. I am really surprised your teacher didn't show you the respective fingerings during your first lesson. Saxes are notorious for having a crappy low range, and one of the first "checks" performed on a new instrument is playing all notes below C4. The low end is actually the easiest. Wait till you get above the top ledger line and into altissimo :)
Try using a mnemonic for memorising the notes at first. Or even write note names next to them in the beginning (I did). The most famous mnemonic is FACE (for notes between ledger lines) and Every Good Boy Deserves Fruit for the ledger lines themselves. The rest is counted downwards/upwards from those and gets memorised by itself in time.
Comment: Incidentally, I've heard hundreds of other mnemonics for the lines (Every Good Boy Does Fine, Every Green Boat Does Float, etc...)
Comment: @user45266, true. There's even a few "adult" versions...


Financial Department Bitcoin

Question: I wanted to send bitcoins to my wallet from my trading account and did not receive anything. A short time later I got from
Fiancial Department Bitcoin received the following message:
Your payment of BITCOINS is ready to be processed and is already on BLOCKCHAIN.
This department wants to pay me bitcoins for a fee and I don't know if this is real? Has anyone ever had anything to do with it and can you trust this depatment?
Comment: This sounds like a scam.
Comment: So this service is holding your money, but wants you to send *more* money, to pay a fee? This is pretty obviously a red flag for it being scam, if they were legitimate they could just take the fees off the money they are already holding for you.
Answer: It doesn't seem right. I wouldn't trust them. I would suspect fraud.

Financial Department Bitcoin

As I'm sure you know, The Bitcoin currency and Bitcoin network is peer to peer and has no departments. So no financial departments.
In normal English, or business English this phrase doesn't make much sense. Some kind of business would have a financial department but those sorts of departments are not usually split by currency. Generally there would be an accounting department that might communicate with creditors and debtors, there might be some kind of sales department or customer services department that communicates with retail customers.

my trading account

If you have an account you are dealing with one of the many thousands of businesses that make money by selling services to people who want to invest or trade in Bitcoin. There are lots of fraudulent businesses that are just invented to trick people out of money. There are also some genuine businesses of this sort but many people find it hard to tell genuine businesses from fraudulent ones.
Finance departments are usually different, here's one definition:

Finance Department is the part of an organization that is responsible for acquiring funds for the firm, managing funds within the organization and planning for the expenditure of funds on various assets.

So in most businesses - the finance department mostly manages internal matters - it is generally not one that routinely interacts with retail customers.
For example a car manufacturer would have a finance department that might obtain funds for a new factory. They might not routinely be involved in selling cars to distributors and certainly not involved in selling cars to car-drivers.
Of course businesses are free to organise themselves as they wish and can name their departments whatever they want.

This department wants to pay me bitcoins for a fee and I don't know if this is real?

If the fees were not made very clear right at the start, before you placed any money in this trading account -- then you are very likely the victim of fraud.
Comment: +1 I admire your grit to suss out this sort of situation again and again.

Financial Department Bitcoin


rxjava observables and scala futures

Question: In a simple webapp I have been using as a playground, I am playing with using rxjava to perform a number of operations in a reactive manner.  I have been using reactivemongo to connect to my Mongo database, but I find that for anything more than a trivial CRUD operation I often end up trying to reduce a Future[List[Future[T]]] into a Future[List[T]].  This can happen multiple times in the execution chain, before I finally hand it back to the Play framework.
I am playing with rxjava to try to convert these reactive operations into Observables, so that I can combine them using rxjava's utility methods, but I was wondering if anyone had already solved this problem.
Here is an example from my most complex action:
def import = Action {
   //scan the base folder for app IDs (Future[List[UUID]])
   val summaries = ftpWrapper.scanUserIdsAsync

   //import all the files in each of those folders (Future[List[LogImportResult]])
   val processResults = summaries.flatMap(lst => {

     //List[Future[List[LogImportResult]]]
     val imports = lst.map(user => logProcessor.importLogFolderAsync(user))

     //fold together the several lists of insertion results into one list
     Future.fold(imports)( List[LogImportResult]() )( _ ++ _ )
   })

   Async {
     //display the insertion results, or throw.
     processResults.transform(r => Ok(views.html.logImportResult(r)), ex => throw ex)
   }
}

The above code calls into my services to do the following:

Locate all folders on an FTP server whose names are UUIDs
Import all files inside each folder into the Mongo database:

check if the file already exists in mongo
if no, then insert the data from the file as a BSONDocument

combine the results of importing each folder into one giant list
display the results in the view

Most of these actions are non-blocking asynchronous, and as such return a future.  I have code all over the place in this app to combine these futures together, so I am interested in seeing if rxjava can simplify that.  I have already been working on some ideas here: https://gist.github.com/gburgett/6106724
So, has anyone encountered something like this?  If so, do you have a better way to go about it than simply combining futures like this?
Answer: It could be the case that using Scala.Rx's reactive variables simplify your use case since they propagate change state as they happen. In particular, chaining those smart Var's together might help you simplify the task. Please have a look at:
https://github.com/lihaoyi/scala.rx
There you also find a link to the underlying publication that elaborates on the concept further.

rxjava observables and scala futures


Error message when trying to make deploy of CommCare app "whoops, that didn't go through. Reload the page and click "Make New Version"

Question: I'm trying to make a new build of a CommCare application and I received the error message "whoops, that didn't go through. Reload the page and click make a new version." I tried to follow those exact directions but I was able to reproduce this message 4 times. I've recently deleted a module in CommCare and I assume this is related. Can someone  help me figure out what is causing this error?
Comment: CommCare is a web based application building platform that does not require any coding to build data collection apps -- it seems more appropriate to ask via commcare tag on web apps because I'm not writing any lines of code, rather I'm using the "form builder" web app version of CommCare. I assume if I'm not contributing to the CommCare code base or writing in a coding language called CommCare, then I should be posting here?
Comment: Hi Claire.  I had a comment conversation with Ben on another post.  We've been hemming and hawing about the best place for questions on the product.  The product is completely new to me, so when I read "build," I thought it was a code issue rather than one dealing with the interface.  We're going to play it by ear, but I will reopen this one for the time being based on the information you have provided.
Comment: Some of the discussion from when the tag was first proposed: http://meta.webapps.stackexchange.com/questions/4100/adding-commcare-tag-to-web-applications.  Feel free to comment or weigh in or ask a fresh discussion question on Meta regarding all of these issues.
Comment: Thank you! Looking forward to being part of this ongoing discussion. So far being able to ask these questions here has been incredibly helpful for my usage of the product.
Answer: "whoops, that didn't go through..." is the default blanket error message that CommCare HQ will generate when something went wrong and it wasn't able to tell you what. Generally in this situation the best option is to "report an issue" so that the platform developers can figure out what's going on and introduce a better error message for future occurrences of the problem.
If you are blocked, I would recommend using the "revert" feature to go back to a previous working version of the application, recognizing that this will cause some of your recent work to be lost.