According to Protestants what transpired when Mary was "overshadowed" in Luke 1:35?

Question:
[Luk 1:34-35 ESV]
  (34) And Mary said to the angel,
  "How will this be, since I am a virgin?"
  (35) And the angel answered her,
  "The Holy Spirit will come upon you,
  and the power of the Most High will overshadow you;
  therefore the child to be born will be called holy--the Son of God.
Comment: That question was closed as "Primarily Opinion Based" presumably since it was a truth question and this site is restricted to ecclesiastical opinions only. The received answer was from a Catholic perspective. Hopefully some Reformers opined on what transpired.
Answer: According to the Bible:

"What is conceived in her is from the Holy Spirit" (Matthew 1:20).
The Virgin Mary "was found to be with child through the Holy Spirit" (Matthew 1:18).
"God sent His Son, born of a woman" (Galatians 4:4).

That's what Protestants believe transpired.  We don't speculate; we just believe what the Bible says.  If the Bible doesn't provide any additional information, then we don't need to know.  God, through the Holy Spirit, was responsible for Mary becoming pregnant.  However, I did find an article on the subject that expresses the Protestant view, part of which says this:

From these passages, it is certainly clear that Jesus' birth was the result of the Holy Spirit working within Mary's body. The immaterial (the Spirit) and the material (Mary's womb) were both involved. Mary, of course, could not impregnate herself, and in that sense she was simply a "vessel." Only God could perform the miracle of the Incarnation.
However, denying a physical connection between Mary and Jesus would imply that Jesus was not truly human. Scripture teaches that Jesus was fully human, with a physical body like ours. This He received from Mary. At the same time, Jesus was fully God, with an eternal, sinless nature (John 1:14; 1 Timothy 3:16; Hebrews 2:14-17.)
Jesus was not born in sin; that is, He had no sin nature (Hebrews 7:26). It would seem that the sin nature is passed down from generation to generation through the father (Romans 5:12, 17, 19). The Virgin Birth circumvented the transmission of the sin nature and allowed the eternal God to become a perfect man.  Source: https://www.gotquestions.org/virgin-birth.html

Jesus, fully human (through being born of a woman) and fully God (through the Holy Spirit).
No doubt you will receive more learned and scholastic answers, but this is the best I could come up with before I shut down my laptop and serve up our evening meal.
Comment: Appreciate your comment - I don't have any academic or scholastic qualifications, just a desire to point others to Christ through Scripture.
Comment: Thank you Lesley. I appreciate all the love into your answers. Peace.
Comment: _We don't speculate; we just believe what the Bible says_  +1.
Answer: What you are seeing in the quoted passage is an example of Hebrew poetry. If you read the Psalms, Proverbs, or much of any of the prophets, you will see a very clear pattern time and again: The author will state something, and then re-phrase that statement. Even though Luke is a Greek, he is relating something that took place in a culture dominated by these writings.
"The power of the Most High will overshadow you" is a re-phrasing of the passage coming immediately before it ("The Holy Spirit will come upon you"). Both passages are referring to the same thing (the Incarnation).


math explanation for using paired-t

Question: Not a math/stats person, but I am interested in finding out why "paired t" would be a preferred test for samples that are not "independent". I googled a bit on this topic, but didn't really find anything that proves paired-t better than Student t for paired samples. Similar questions have been asked on this forum, so I got the gist (hopefully correctly) - paired samples tested by student t will lose the power of detecting the difference (i.e. accepting the null hypothesis when one should not) ?? Any suggestion where I could find the math treatment on this issue or a more elaborated explanation ? Great many thanks.
Answer: It's not that paired t is "better" (whatever that means), it's just more appropriate. All data is correlated in some way. Sometimes it's just a chance correlation and the underlying data are theoretically independent or it's a correlation due to an underlying factor like measures taken from the same subject. The independent test treats the conditions as if they are independent whether they're correlated or not and the paired test uses correlations present in the data.
It's entirely possible for a paired test to be "worse" mathematically in terms of less powerful or having higher error rates. But that's not why it's used.

math explanation for using paired-t


Import Cookies from Google Chrome Mobile to another Mobile browser

Question: I would like to know that is there anyway I can import cookies from Android version of Google Chrome to any other mobile browser (on the same device)?
Just like when we install Firefox/Opera/Chrome on PC, they ask you to import cookies and stuff from other browsers.
Answer: No; apps on Android do not have access to each other's data/files unless they are stored in a common external location, which cookies are not.
It might be possible to do this as root but I would suspect that they are using different formats/layouts.


Is it a bad idea to use a bitcoin wallet address in a domain name or URL?

Question: Aside from it forever being public and kind of marrying a business to a wallet.
Comment: What do you mean by using a wallet address as a URL? If you type a bitcoin address into a browser, it won't send you anywhere useful.
Comment: yes, I meant like http:/1AJumUtyfXC47cwii5CHYHkhXRHuPTQ3F3.com
Answer: If you mean as part of a URL or domain name, then yes, I think it's a bad idea. If your private key is somehow compromised (eg through a stolen or hacked PC) you may no longer want to use that address, but your users may have it in their bookmarks for years afterwards.
However, as long as it didn't have any particular meaning (such as being accompanied by an instruction to donate to that address), it may not cause any harm. Secondly, it's easy to redirect a user's browser to a new page if you need to.
Usually URLs are best kept short unless it's a sub-section of a site used for sharing or bookmarking. Keeping them looking like words (as much as possible) helps with usability, so unless your vanity address is the longest ever generated and you want to show off, I can't see a good reason to include it there.
Comment: Good points, thanks. It's probably interesting short term, but a huge pain longterm.


2010 Honda Civic occasionally can't shift into first or second gear

Question: I have a 2010 manual Civic. Very infrequently, I cannot move the shifter all the way to the left (the first time this occurred, I thought I was in first when I had really shifted into third). The car still shifts smoothly into third, fourth, fifth, and reverse when this occurs.
The issue starts after I have been driving for a while and resolves itself after a few minutes. It has only happened twice in the past five months. I had a shop check the transmission fluid level a few months ago and they said it was fine. If it was a mechanical issue with the fork or syncros, wouldn't if happen more frequently?
Comment: Check your shift linkage bushings for wear.
Comment: Do you remember anything about the weather on the days shifting into first or second was hard?
Comment: There wasn't anything special about those days. No rain or high humidity. About 80 degrees.
Comment: First and second are the gears that see the most usage and subsequently most wear and tear. In my experience, worn synchros are sensitive to transmission fluid temperature (especially when cold). The intermittency of the problem is probably down to how much slack the synchros are expected to take up during the gearshift.
Comment: No trouble there. See my answer below.
Answer: I have a 2003 Toyota Yaris and this does the pretty much the same thing. Very hard getting it into 1st and 2nd (pretty much won't go in at all when cold). I have to try it a couple of times sometimes when cold. These cars have worn down syncros (mine has 79k, clutch replaced at 74k) and that's some of the reason why this happens (there could be other reasons, I'm just not sure, I just live with it - probably not the best idea).
Pretty much all non-new cars (I've never owned a new car so maybe they do, I'm not sure) will have stiff gear changes from cold, and improve after a few minutes as you mention in your question. I know changing the gearbox oil does rectify this. I'm not sure if you've had yours replaced or not? Could be worth thinking about dependent on mileage of your Civic - this won't fix the problem that you're having in 1st and 2nd, but it should help all gears and might help 1st and 2nd a little.
Now a lot of Japanese cars won't go into 1st at all unless the car is almost stationary (not sure why this is, it definitely happens to me, Regular Car Reviews referenced it in one of his videos too) so this could play a factor (I'm not sure at what wheel speed you're trying to engage first at).
It certainly seems strange that your problem doesn't arise more frequently, I guess there could be factors why this occurs (how long you usually let the car warm up etc). My advice to you (and what I do in my Yaris) is treat 1st and 2nd very gently, especially from cold. I give those two gears all the time in the world to engage, I'll release the clutch and try again so I don't have to force it in. One thing I've just thought of while writing this, try and engage all gears once or twice before you start the engine and see if that helps with gear selection - I've heard it helps, but I've never tried myself.
Comment: Great answer. +1. I should add that cheap cars have probably more marginal synchros than expensive cars. My father's VW Passat (quite expensive) with manual gearbox didn't develop any synchronizer problem while my Toyota Yaris (very cheap) did, although the VW Passat in the end had more kilometers on it.
Answer: After checking everything from the shift knob to the end of the linkage, we determined the issue must be internal to the transmission. I didn't have the wherewithal to crack it open myself so it went into the shop. They didn't do as much forensics as I would have liked, but after they rebuilt it the issue went away.


increasing display brightness on vaio laptop fedora 9

Question: I have fedora 9 on sony vaio with dual boot. But Fn keys dont work. Is there any other way to adjust brightness ? I have ATI graphics card.
Answer: You can use xgamma:
xgamma -gamma 2.0

default is 1.0, anything higher will brighten the output from the X server (not the laptop's backlight though) so it shouldn't use more battery.
Answer: Try spicctrl, which is at least present in the F11 repos:
spicctrl
sony-laptop
I don't have a VAIO, so can't comment on spicctrl in action.
Also, not sure about F9, but rpmfind turns up (for i386):
F9 i386 rpm


Didn't fur out a shower pan

Question: I recently installed and tiled a shower pan.  I did not realize that this particular pan needed to be furred out in order to install glass shower doors. Do I have any options or workarounds that would allow me to install glass shower doors without tearing down the tile?
Comment: Furred out how? Do you mean so that the tile was on plane with the pan walls?
Answer: I assume that you're hoping to install a swinging glass door set that would normally require that the tile and shower pan walls be on the same plane, with the problem being that the hinges won't align as you have it now. I see two options (aside from redoing your tile):

Install spacers for the upper hinge mount points. These could be made of faux marble or constructed with your tile so they match. They could be simply small blocks or essentially short walls that reach to the height of the door glass. If you go with small blocks the gap between the door and wall will be larger, but it may not be an issue.

Profile view:
<code>|    |
|    |< -- door glass edge
|___ |
    ||
    ||< -- hinge location with spacer block (or stub wall)
 ___||
|    |
|< --|---- tiled wall
|    |
|    |
|    |
|    |
|___ |
    ||
   <||- -- pan wall
    ||
    ||
    ||< -- hinge location
</code>

Order a custom door kit. Glass shops will be able to accommodate you with notched glass and/or custom hinges and/or chrome rails for above the pan.
Comment: Thank you. I will most likely be going with the custom door installation.

Didn't fur out a shower pan


Which public cloud is the best for migrating to and from?

Question: Each public cloud (Azure, AWS, Rackspace etc.) has its strengths and weaknesses.  Some public cloud offerings tend to have more "vendor lock in" than others.  Which public cloud is very good for migrating to and/or from?
Answer: I've been a Linode customer for 15 years now... I have yet to see a reason to change, at least for my own use cases.
Edit for clarification - why do I think you should look at linode?
You have total control over just about every aspect of each of your virtual machines.  You pick the distribution, you install and configure the software and services. If you have multiple machines on your account, you can get a private network between them all in the data center.  The basic $10/mo plan beats the cheapest micro instance that AWS provides (at least when I checked 2 years ago).  Partial use billing - need a machine for a few hours to make a backup before a big upgrade? No problem, pennies per hour, or for longer use prorated for the month.  Some extras like more IP addresses are cheap ($1/mo).  The few times I've contacted support (paying via PO, other billing related special requests) they have responded quickly and in a positive manner.
Edit 18 months later...
Linode is still king as far as I'm concerned.  You can now get micro instances for $5 per month, and they've introduced mass block storage - not quite as fast but at their pricing adding storage is now silly cheap.
I know this seems like a shill, but I'm not associated with them in any way other than as a very satisfied customer
Comment: @SteveBarnes - I think that's implicit in the fact that you control everything on the VM. There's nothing easier to get into and out of than something that's completely under your control.
Comment: What makes you think that it is good for migrating to & from?


Number appears on Trello board tab

Question: While I'm using the Trello application online, there is a number that appears next to my board tab.  It looks like there is a notification or message that I'm missing but I can't figure out how to access it.  I just added someone to the board and they are now able to access the information but I was curious as to what this number was.
Comment: As the answer below mentions, including a screenshot will go a long way in explaining the problem.
Answer: A screen shot might help explain what you are asking about.  Short of that...
Generally, with Trello, anything new or different appearing on your Trello screen can be clicked for more information.
Example:  The notification bell in the top right corner turns red when changes made by other people or due date notices for you are available to read.  Click the bell and the notification bar opens where you can read the updates.  Click away from the bar to close it and clear the notification notice.
I suspect the numbers are related how many unread updates have happened since you last read them.
Comment: I agree. For future readers, possibly related: https://webapps.stackexchange.com/questions/85508/what-does-the-number-in-trello-title-mean

Number appears on Trello board tab


How to change fps character's movement speed and mouse sensitivity in UE4?

Question: As the title says, I'm using the default fps template from UE4 (blueprint template) and the movement speed is very high, also I want to adjust the mouse sensitivity, but I don't know where are those values, nor the variables, and my other question is... Where are those values/variables?
Answer: The player has a max speed which I've found useful for lowering speed when a player runs out of stamina.  To set it up to lower the speed from the beginning, use connect the following to your BeginPlay:

If my memory is correct, the default walking speed is 600 so adjust yours accordingly until the speed is what you want.
With the mouse sensitivity issue, this is just a guess because I've never done it myself but in the Input Settings (Project Settings->Engine->Input) the default scales for InputAxis->Turn are 1.0 and -1.0.  I would presume that if you adjust these to lower values, the mouse would move slower.


Send serial data to Macintosh SE?

Question: I am new to anything vintage computing and would like to build a simple project with my Macintosh SE. My Hello World goal here is to simply show a string of text received from the serial port on the Macintosh SEs display, and I'm not sure where to start.  I gather that I will connect to it with a null-modem serial adapter, but how will I receive the data sent over the serial on the Macintosh? Is there a Terminal application in the OS or anything that can monitor the serial port? Any pointers appreciated.  I'm looking for an explanation of what, other than connecting the cable/adapter, I need to do to use the serial port for communication and what is the simplest way to get my feet wet and just prove that a message can be received over serial.
Comment: All Mac serial ports are female, the male-male printer cable does the input-to-output swap.   Extension cables are straight-through, but don't connect two Macs, or a Mac and printer, having the wrong gender on one end.  No one ever called the printer cable 'null modem', but it has that function.
Answer: The OS itself has no terminal application by default. There have been multiple terminal programs available in earlier times, though. The most prominent and easy to use might have been zTerm. Double-click with shift, choose port, set serial parameters from the popup-menus at the window bottom and you're good to go.
Search for zTerm in your favourite old Mac software collection, such as InfoMac or UMich.
Apart from the correct cable, switching the symmetric RS-422 Port to RS-423 mode by earthing one pin (can't remember which), there was much fuzz in earlier times about "hardware handshake cables" — which might be worth consideration when you want to seriously transfer data. The Macintosh lacks some pins to provide the necessary "inner" (RTS/CTS) and "outer" (DTR/DSR) handshaking to signal the peer to pause sending data, end the connection, etc.
Comment: I remember that contemporary modem cables had no active circuitry. While RS-423 (asymmetric) uses 5V signaling, RS-232 uses 12V. However, binary thresholds of the RS-232 standard, and safety measures in the Mac's buffers permitted both directions to work flawlessly.
Comment: Re, "RS-422," "RS-423," Buffer circuits that convert between RS-422 low-voltage differential signalling and the higher-voltage, single-ended signals of RS-232 are widely available. Google "rs-232 to rs-422," and you'll find dozens of them.
Answer: One of the earliest Mac program to access the serial ports was MacTEP, a Basic program that ran using Microsoft Basic 1.x, to poke the correct baud rate settings into the SCC chip and then peek and poke at the SCC data register to input and output serial data.
Any programming language you can find that runs on a Mac SE (Consulair C or MacForth, et.al.) could probably do likewise.

Send serial data to Macintosh SE?


Using *Autotools*, how do I save the compiler listing on a file by file basis?

Question: Please understand I'm using Autotools / Automake / Autoconf, and I can not use redirection because it needs to be applied command by command in the make file generated by autotools.
I need a way for to have autotools create a make file which has provisions for generating and saving the compiler and/or assembler listings associated with each individual source in the package.
My first try was to add '-Wa,-acdhln -g' into CCFLAGS.  This indeed produced a composite c/assembler listing, but it went to the terminal, not into a file.  If I captured the make output (using redirection), I would have 47 different listings strung all together along with interspersed build commands.
What I hoped would happen, optimistically reading the GCC doc Overall Options - Using the GNU Compiler Collection,

-o file
      Place output in file file. This applies to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code.
If -o is not specified, the default is to put an executable file in a.out, the object file for source.suffix in source.o, its assembler file in source.s, a precompiled header file in source.suffix.gch, and all preprocessed C source on standard output.

is for files {file}.o, and {file}.s to appear, based on the "-o {file}.o" in the GCC command line.
What happened is that the assembly listing was apparently sent to standard output.

EDIT to add 23 Oct 2016.   I now realize the documentation was talking about thing like the compiler output file passed as input to the assembler, and the assembler output file passed as input to the linker.  Neither would be the assembler LISTING file which I want to capture.
This also applies to the using the -save-temps option; it would only save the output from the assembler, which is the linker input file, not the assembler listing file.

An alternate interpretation of the doc could imply that every output file would be placed in the one single file named in the -o operand, either intermixed, or with the last created file overlay previously created files.  (For example, the output from the compiler pass overlayed with the output from the assembler pass overlayed with the output from the collection pass.)
As this seems to be counter productive, I assumed that GCC (the top level executive) might be smart enough to adjust the file name for different passes.  This does not seem to be true.
Omitting the file name from the "-o" would seem to exactly what is wanted, save that the object file is always named "a.out" instead of "{source}.o".  Why a constant for the source output name was chosen makes no sense to me, but a rename step after each GCC invocation could change "a.out" to "{source}.o".
Consulting the GNU Assembler documentation says even less about -o, and has no option for dealing with the output listing.  One assembler version, tigcc, documents that the listing is emitted as standard output.

Did the GNU and GNU Build Standard revisions to Unix not address this?
(Am I insane, or am I just living in an un-reality called Unix? ? ?)

So now it looks like Make needs to tell GCC that when the assembly step is executed, that standard output should be placed in the $@.s file.  I suspect this can't be done, given how the GCC options appear to behave (and a quick look at how specs files are used).  Perhaps Automake (or libtools?) can create a multi-stepped compile operation, separating out the various steps out so the assembly output can be captured.
But, since the make file is generated by autotools, I need a way to tell autotools to create the make file that will create/capture the assembly output file.  This task would seem to require re-writing some of the autoconf/automake rules and/or macros.
Finally, I'm working with a package someone else created using autotools, tar-balled up and downloaded to me.  I didn't do the autotools packaging, and I didn't create the giant *.ac files, and I don't want to hack on them, if at all avoidable.
I just need to get some assembly and link maps to try and debug a problem with the package.
Comment: Have you looked into the gcc option -save-temps? AFAICT, this may be what you want.
Comment: @Bjorn Sorry to report that -save-temps only saved the INPUT to the assembler, not the output listing.  Actually, you need -save-temps=obj, otherwise the intermediates may not be saved in the same directory as the object (which generally follows the source in most generated commands).  There is a warning about running multiple compiles at the same time and have the intermediate files interleaved when the =obj form is NOT used.  That bothered me enough that I added MAKEJOBS=1 to the "make all" and "make install" commands in my script.
Answer: I finally broke down and wrote a real program that analyzed the captured terminal output and extracted the listing files.  While it works for my specific system / build configuration / package, I can't offer it as anything more than an example.  It's certainly not a readily usable tool.
I'm sorry this really isn't a general answer to overcoming an autotools short coming.


Why is proving something is NP-complete useful, and where can I use it?

Question: I trying to understand where, as a programmer in situations where it can be good to do a
NP-complete reduction to prove that a problem is NP-complete, why is it good to do that as a programmer? I don't understand.
Comment: It is always useful to obtain lower bounds on problem complexity to avoid searching fast solutions in vain.
Comment: Why isn't this closed as either too broad or as a duplicate?
Comment: @PeterMortensen, If you think it should be closed as "too broad", I suggest the most fruitful path would be to make the case for why it is too broad, or flag it for closure.  If you think it should be closed as a duplicate, I suggest the best way you could help would be to identify what question you think it is a duplicate of, and then flag it for closure as a dup of that question.
Answer: When dealing with a problem, knowing how to recognize a $\mathsf{NP}$-hard problem can prevent you from hair loss trying to find an efficient solution (as it is thought that $\mathsf{P}\neq \mathsf{NP}$).
Reductions can also be seen in a "If I know how to solve $A$, then I know how to solve $B$" way.
When confronted to a $\mathsf{NP}$-hard problem, you can then think of ways to deal with intractability.
Comment: It is not so much "it is thought that P $\neq$ NP" but rather "it is thought that a programmer will not accidentally prove P = NP by writing code".
Comment: It does not mean that there is no efficient solution, but that it is **very likely** that there is no deterministic efficient solution on every input. That is not necessarily completely out of the question to solve the problem. For example, SAT solvers are known to be very efficient on a lot of boolean formulas (even if there are some formulas where they fails).
Comment: @Stef It's definitely thought/believed that P ≠ NP, it's just that no-one has figured out how to prove that yet.
Comment: @JonteYH Efficient algorithms for specific cases of NP-complete problems rely on something that is specific to those sets of inputs, that you may not be able to apply to other inputs (e.g. running something over finite-ranged integers instead of floating points or unbounded integers). If you have an algorithm, you should also have the complexity, which would tell you how the running time would change for other input parameters. (It may also be that e.g. an exponential-time algorithm runs in linear time for some inputs, which is basically just getting lucky).
Comment: @Stef And if they do, accidentally, they get an offer from [the Laundry](https://en.wikipedia.org/wiki/The_Laundry_Files) that they cannot refuse ;-).
Comment: Thanks does it meaning that i prove that a Problem is NP-Complete it means that there is no effiecient polynomial solution to it also?
Comment: I mean it is very likely to encounter an input to a NP-Complete problem that takes too long time to solve because NP-Complete also is NP-Hard?
Comment: Yes, that's true.
Answer: If a problem is NP-complete that means that lots and lots of great mathematicians, computer scientists, and very clever software developers have not been able to find an efficient solution for the problem. And that means nobody can blame you if you can't find one. If you could find one, they'd introduce a Nobel prize for computer science just for you. (Roughly quoted from memory from Garey-Johnson, Computers and Intractability, 1979).
Comment: Nitpick: You not only have to find an algorithm, you also have to prove it is efficient. We do have existing algorithms which are known to solve NP-complete problems in polynomial time iff P=NP.
Comment: @Maya Making such an algorithm can be implemented via dovetailing, and is at the level for which (with the right context) an undergraduate might be expected to do so as part of coursework.  I can't find any published sources describing such algorithms, but there is [a post on code-golf](https://codegolf.stackexchange.com/a/195215) which implements such an algorithm on the subset sum problem.
Comment: @SriotchilismO'Zaic That sounds interesting. Any search terms or links you can recommend?
Comment: @SriotchilismO'Zaic of course, the algorithm in that Code Golf is a rather extreme example demonstrating that just because a problem is in P, it does not at all mean we can efficiently solve it in practice.
Comment: If there was an algorithm that solves an NP-complete problem in p(n) time (even if I have not the slightest idea what the algorithm is), then I can write a program that generates algorithms, runs 1 step on the first, then 2 steps on the first and one step on the second, ..., then n steps on the first, n-1 steps on the second, ... 2 steps on the n-1st, 1 step on the n-th algorithm and so on, and I find an algorithm that works in fixed time c, and solve the problem in p(n) * max (p(n), c) time = polynomial time. (Better check it).
Answer: Knowing about NP-complete problems is part of the cultural baggage of every computer scientist, as is the case for other core results (such as the non-computability of the halting problem). NP-complete problems arise in practice. The maximal independent set problem for graphs is aimed at simultaneously exploiting a maximal amount of resources that are not dependent on one another.
Theoretical computer science focuses on extremes: problems that are not computable, problems that are too hard to compute (for larger sized instances), limits of computational speed up, limits of compressibility etc. You can interpret these results (from a practical point of view) as guard rails you need to know about in order to make reasonable decisions about new problems. Some of these problems turn up in practice in different guises. The reduction process helps to show that a new problem is NP-complete by linking it (in the chain of NP-complete problems) to a known NP-complete problem. As pointed out in the first answer: when this happens it is reasonable to stop searching for an efficient solution (unless the aim is to resolve the long standing open problems related to NP-completeness).
Theoretical results may appear at times to stay far from practice. They do impact application areas: the halting problem indicated the need to develop real-time programming languages by restricting higher level constructs. The limits of compressibility and running-time speed-up support decisions on when it is reasonable to give up on trying to optimise code for certain applications.
Answer: As a working programmer, you need to recognize when you are being asked by the business to do the literally impossible.
Assuming  ≠  (you don't need to understand what that means, just know that most of us do), then when you are being asked to solve a problem that falls into NP the solution is going to necessarily be slow (although it may be fast enough in practice).
But if you are told that your map direction calculations for the shortest route that visits cities A, B, C, D, E, and F is too slow, you need to understand that there is a hard bound on how fast it can be.
That's why it's important to understand broadly the sorts of problems in the NP space and why people ask about them (sometimes in disguise) in interviews: you need to be able to recognize immediately that the objective is unachievable and start brainstorming workarounds or trade-offs to hopefully still achieve the business goals.
Comment: Then of course, you can push back and say "we won't find the shortest route, but we'll find one that's reasonably short". IIRC the traveling salesman problem does have algorithms that find "reasonably short" routes efficiently.
Comment: @user253751 pretty sure it does, my point is just more that business people are even less likely than programmers to know what's hard/easy and part of the job is to explain it to them and then help solve the problem anyway.
Comment: There are many instances of NP-hard problems that are routinely solved. There is nothing "literally impossible" in writing a program to solve a 0-1 integer programming problem. Such things are solved all the time in operations research, frequently with fairly large problem sizes. You allude to the Traveling Salesman Problem. The state of the art in TSP is capable of doing things like finding real-world optimal tours through tens of thousands of locations.
Comment: As a programmer, over the years I've been asked to do multiple things which are impossible to solve, but I don't recall ever having asked to do something which is NP-complete. (Note also that NP-complete problems are not literally impossible to solve -- they are possible to solve, it just means they may take a long time to solve for specific inputs).
Answer: As a programmer, you likely do not need to pay much attention to the class of NP-complete problems.  The class of NP problems is much more useful.  Obviously, if your problem is NP, it cannot be solved for all inputs in polynomial time (by a deterministic Turing machine, and assuming $P\ne NP$... which is currently considered a pretty darn reasonable assumption)
The easiest way to prove that your problem is NP is to demonstrate that, were you to be able to solve your problem in polynomial time, you could also solve an existing NP problem in polynomial time as well.  This is what they mean by a "reduction".
For mathematicians, the idea of NP-completeness is very useful.  Completeness says that you can reduce any NP problem to any NP-complete problem.  This is very useful for the topic of $P=NP$.  If you could find a polynomial time solution to any NP-complete problem, it is trivial to show that you found a solution to every NP problem, thus demonstrating that $P=NP$ without having to mechanically exhaust every last NP problem, one by one, demonstrating that every one of them was infact P.
As a programmer, the best use for NP-complete I have found is to take advantage of the raw amount of effort people have put into exploring good algorithms for dealing with them.  I may be working on a problem that's totally unique to my domain, but if I can transform it into another NP problem that people have indeed worked hard on, I may be able to leverage their work.  This is especially true for the SAT problems, for which a tremendous amount of work has been done.
As a simple example, in SAT problems, there is often a particularly difficult class of problems that take the form (a|b|c)&(d|e|f)&...&(x|y|z), where a, b, c, ... z are literals (possibly negated), and they aren't all unique (i.e.   d may be the same as ~a).  In many cases, it is easy to show that the complexity of satisfying that expression explodes as the expression gets longer.  But sometimes my problem doesn't call for such expressions.  Maybe mine has a limit in how many terms it uses, bounding the exponential growth to something palatable.  Maybe each term has no more than one negated term (which makes those Horn clauses -- satisfiability of Horn clauses is in P.  In fact, it's linear!).
Sometimes you get lucky and find that, when you do the transformation, you get something really easy (like the Horn clauses mentioned above).  In those cases, you might simply figure out what the analog for Horn clauses is in your problem, and just code it up yourself.  Other times there's some amazing math behind it, and the easiest way to solve your problem is to actually reduce it to SAT, and solve that.
If I have a problem that is NP, it is NP.  I can't leverage other mathematicians to magically make it P.  However, often I don't actually have a NP problem.  I really have a hard-to-describe subset of a NP problem that I called NP out of laziness or ignorance.  If I transform my problem into another, I can also tranform my real inputs.  There's a decent chance that my real problem fell within the range of a previously explored P region of a NP problem.  SAT, for instance, has been mightily explored.  We're actually pretty darn good at finding ways to satisfy many boolean expressions.  Maybe an existing SAT solver has a polynomial time solution for all of the reductions of my problem within the limited inputs I need.  It's easy to prove they can't solve them all (because SAT is NP), but dang if we haven't made great advancements on many cases!
It's also helpful for demonstrating when I'm not so lucky.  If I can take a "hard" problem from SAT, and show that solving my problem requires solving my problem too, then I show one of the following:

My problem is NP-complete
My problem requires exploring a P sub-problem of a NP-complete problem like SAT which the state of the art from hundreds of mathematicians hasn't solved yet, or.
I need to come up with a more clever reduction to sidestep the issue

This does a good job of focusing my attention.   Should I really be trying to solve this problem?  Is this problem perhaps NP? (even if I haven't proven it formally).  Am I capable of finding the more clever reduction? (which, if I can find, shows how I may be able to use the existing proofs for SAT to solve my problem)
Other than that, NP is far more useful for programmers than NP-complete.
Well, maybe.  I have found that, when explaining why we shouldn't do something, the term "NP-complete" rings really nicely in people's ears.  There's something about the word "complete" that suggest finality, even when your audience doesn't really grasp P vs NP.  NP-hard is another useful word, but I find NP-complete does the job really well.
Comment: Your answer seems to use "NP" to mean "Not P" (for example, when you claim that "Obviously, if your problem is NP, it cannot be solved for all inputs in polynomial time"). P is part of NP. Checking if a list is sorted is in NP, but can obviously be solved in polynomial time.
Comment: English is not my mother-tongue so i wonder what do you mean by " I may be able to leverage their work" is there another advantage when you show that a problem is NP-Complete besides it may not exist a effecient algorithm so solve the problem?
Answer: To argue in front of your boss.

Source: https://www.ac.tuwien.ac.at/people/szeider/cartoon/
This cartoon is originally from the famous textbook Computers and Intractability by Garey & Johnson, but adapted to the current Zeitgeist.
PS: Concerning the adaption, I would prefer to see real parity here, i.e., having one Alice and one Bob and not Alice two times, but I am not sufficiently talented to modify the cartoon.
Comment: That's Alice and Bob. Don't let the manbun fool you.
Answer: I once was working as a consulting company where we were writing software for a warehouse management system.  One of the requirements was to generate pick lists that would optimize the loading of trucks.  My manager came up with an algorithm that he thought would work.  It turns out that what he came up with was really just the Bin-Packing Problem, which is known to be NP.  He was not familiar with the concept of P and NP, but I was, and I was able to convince him that his solution would not scale, no matter how powerful the computer was that ran the algorithm.  This probably save us several weeks of development time.  We ended up implementing a heuristic based algorithm that was not optimal, but which worked well in practice.
Comment: It would be great to have more of those examples for courses covering this topic. Thanks for sharing.
Comment: One problem was posted here that looked as if it had a greedy algorithm that worked quite well. It turned out the greedy algorithm worked in 99% of the cases, and would cut out a ton of work and leave a (usually much much smaller) NP complete problem. You really had to work hard to create instances that were "fully" NP complete. (What do I mean by that? Imagine something like the Travelling Salesman Problem, but with so many restrictions so that you can very often reduce a problem of size 1000 to a Travelling Salesman Problem of size 10).
Answer: In my sens, Proving NP-Completeness of a problem, can let you try general solutions.
There are some general or maybe efficient (easy to implement and customize, more understandable or representative, scalable, a better parallel version) solutions for any problem. By term "general solutions", i mean interpolation, modeling, approximation, meta-heuristic search algorithms and optimization, ... vice versa.
Using these general solutions is reasonable only if you don't know the true solution or algorithm. So performing a research for proving that a problem is not a NP, or its solution could be approximated by easier algorithms with acceptable result, or it is reducible to some P algorithms, is a valuable effort. This value of this research is depended on use-case (problem), i.e. in a small company it is not valuable.
Answer: When you decide on a cryptographic scheme you want to know that cracking it is an NP complete problem --- that is, you want the encoding/decoding scheme you want to be as hard as possible to crack.
For example, RSA encryption relies on the NP-complete problem of factoring (very large) numbers into their prime factors.
Comment: Factoring is not known to be $\mathsf{NP}$-complete.


Calls and messages won't come through when screen is locked iPhone SE

Question: I've been having this issue for a while now and even the newest iOS didn't seem to solve it:
The problem is that sometimes I just won't receive calls and/or messages.
I figured it happens completely random, but in most cases it happens when the screen is locked - that means, even if I am passively using phone - listening to music and if the screen is locked, I'd sometimes get missed messages/calls - It doesn't ring, I don't get any alerts until after I wake up my phone. Then I get the notification of a missed call or that of a message that was delivered x minutes ago.

'Do not disturb' is off, I've also talked to people who couldn't reach me because of this problem and they said the phone was just ringing until the call was eventually dropped.
I've sent the list of missed calls to my carrier in case the problem might be on their side, but they've been unable to find anything out of the ordinary. So I guess the problem must be with the device itself or with the software.
Resetting network settings also doesn't seem to help at all.
Notification preferences in Settings → Notifications → Phone are all good. See comment under answer below: https://apple.stackexchange.com/a/379272/313842

I really like this phone, but if it doesn't serve it's main purpose, what can I do with it?
Comment: Did you check Settings → Phone for any misdone setting?
Answer: Since you didn't mention whether you checked it or not: Go to Settings → Notifications → Phone.
Enable Lock Screen, Enable banners, Notification Centre, badges, Show previews when unlocked (or acc to your preference) etc.
Comment: Hey, thank you for your reply.
Lock screen, banners, notification centre, badges etc. - everything is enabled. Banner style is set to 'persistent'. Show Previews is on default (Always) and Notification grouping is set to Automatic.
With messages it's the same expect for the banner style which is set to Temporary.


How long before a flight can I show up in the AA Admirals Club?

Question: If I arrive in the early morning at an airport for a late afternoon or evening American Airlines flight, and purchase a day pass for the Admirals Club, how many hours before the flight will they let me in?
Answer: There's no time limit - as long as you're traveling that day you will be allowed through security and allowed into the lounge.  You don't even need to be flying AA - as long as you can physically get to the lounge and have paid your money then you will be allowed in.
The only real restriction is if you are planning to check luggage, in which case you will not be able to check your luggage until ~3-4 hours before the departure time of the flight.
Answer: I was turned away for showing up too early at the Admiral's Club in Buenos Aires (7 hrs prior to boarding of a 10 pm flight). Maybe the policy varies from club to club, but I was told 4 hours max, so come back later.
EDIT: I was totally wrong. I mistakenly went to the Tsar Alliance lounge when I meant to go to Admirals Club. The issue has been clarified (sitting in the AA club now). When I asked, AA clarified their policy.  It's a true "day" pass so it should not matter how early you show up. I was also told it is good at the destination airport if you travel overnight.
Comment: Day pass and AA boarding pass. Maybe that's why Star Alliance didn't want me hanging around :-)


Seeking Shapefiles of Restaurants in South Florida?

Question: I am doing a project on food trucks for my Intro to GIS class and am looking for locations of places to eat here in South Florida to overlay with places of business. I would like to make a map of which employees have no place to eat for lunch to provide to a non-profit organization that has a job-training program on a food truck.
Comment: Possible duplicates: [GIS data for fast food industry](http://gis.stackexchange.com/questions/7749/gis-data-for-fast-food-industry) and [Available US State or National business (or employer) database lists?](http://gis.stackexchange.com/questions/4709/available-us-state-or-national-business-or-employer-database-lists)
Comment: I don't feel this is a duplicate of those questions. The question is specifically asking about Florida. Unlike those other questions, the asker has a clear research goal in mind thus making it easy for the responses to be tailored towards their purpose. This question itself could definitely be used as a reference for other researchers in Florida, or others hoping to approach the same type of problem.
Answer: Cloudmade do extracts from OpenStreetMap data suitable for loading into Satnavs or GIS packages. For example, the Florida data is here:
http://download.cloudmade.com/americas/northern_america/united_states/florida#downloads_breadcrumbs
if you download and unzip florida.poi.gpx.zip you'll see a florida_Eating_Drinking.gpx file which has coords and names of restaurants. These files can be read into QGIS or any mainstream GIS package.
The Cloudmade files seem to be a couple of years old, if you want more up-to-date locations you can probably get that from OpenStreetMap itself, but there's a bit more data-wrangling to do.
Answer: OpenStreetMap is your best bet. You can download the data using built-in tools in QGIS. See the step-by-step instructions at http://www.qgistutorials.com/en/docs/downloading_osm_data.html
Answer: It seems like you are looking for a couple of different resources. Now, I actually found an interesting administrative resource you may want to look into here. From what I can tell, it is tax roll data that lists information on businesses that include address, and census block group id, thus allowing it to fit into GIS models. Not only that, according to the codebook, this data seems to identify businesses that are restaurants in the field "DOR_UC". So, you have data for locations of restaurants, but that seems to be only a part of what will help with your problem.
The next part is comparing this with areas high clustering of workers who are not near places to eat.
Your next resource, the LEHD Workforce Area Characteristics (WAC) will tell you the demographic characteristics of businesses, and thus can give you an approximation of where the densest areas of workers are. If you want to know more about how to use this dataset, consult the technical document. And for reference, you'll be using this shapefile for the LEHD data.


What settings will be good for taking photos of falling leaves?

Question: I've been trying to take good photos of falling leaves but haven't had much success. Has anyone got any tips for me (exposure etc), or do I really need some specialist equipment? (I am using a Canon 1000D (Rebel XS in the US) and the basic kit lens). If you've taken a successful photo of this kind, please post it and the settings/equipment you used.
Comment: Having an example of unsuccessful attempts might hint us what you were aiming for and perhaps give better advice. And by the way, welcome!
Comment: Are you hoping to catch them mid flight?
Comment: I'm curious to see the suggestions, I've never tried this myself, but given falling leaves will be more unpredictable than birds in flight, I expect it would be quite a challenge.
Answer: Well, I have one picture with leaves, but I used flash to catch them mid-flight.

(shot on 1/250 sec, f/5.6, ISO 100, there was CTO-gelled flash on camera right)
Obviously, we had to throw leaves in the air by ourselves.
If you don't have flash, I'd suggest shutter around 1/250, open aperture as much as you can, focus to half a meter, and then throw leaves to that area. That might result in something interesting. (Just a thought.)
Answer: I think it varies, depends on what you're trying to do. But my guess is you'll always need some kind of light: either flash light (as in che's photo) or back light (like I was trying to do in my photo)
Answer:
This is a certainly technically imperfect example (manual focusing quickly in severely windy and hand-chilling conditions....), but relevant because it shows some leaves illuminated (well, overexposed :) by severe flash usage, some only by natural light. Metz 45CT, full blast, on ground several meters away from camera, radio triggered, Series 1 19-35mm wide open (can't remember zoom setting,adapted) on Sony APS-C at ISO 1600, with the original Metz red filter. Would work with any similar camera.


Is "quasi planet" habitable for life?

Question: I was imaging a system which has a black hole, a star and Earth like planet. The star and planet orbits around the black hole, but the planet has same orbital period as the star, which is a "quasi planet" of the star (see:this, at this case, the Earth is replaced by the star and the quasi satellite is replaced by the planet). Is this planet habitable for life?
Comment: Needs way more information. WAY more information. Too broad.
Comment: Not only does this question lack details enough for a decent answer, it's also grammatically ambiguous: How can a star be a "quasi-planet" of itself? Still, the answer to your question is yes, because you haven't specified what kind of life needs to exist there.
Answer: The orbits of quasi-satellites don't stay that way in the long term (see here: https://en.wikipedia.org/wiki/Quasi-satellite).
"Over time they tend to evolve to other types of resonant motion, where they no longer remain in the planet's neighborhood, then possibly later move back to a quasi-satellite orbit, etc."
This means that the star-planet distance would change drastically over time.  During quasi-satellite epochs the planet's climate might be relatively stable but then it could freeze over for a long while, then perhaps return to a stable state.
A more promising setup could be simply to have a planet orbit in the star's L4 or L5 Lagrange points.  If the Sun's orbit around the black hole were 1 AU in size, then Earth sitting at L4 or L5 would be 1 AU away.  I think this could work, although there would be really strong tidal effects from the BH that could potentially lead to stability issues.  Maybe this would work better with a brighter star so that it could be farther away.  E.g., if the star were 16 times brighter than the Sun then you could scale up all the orbital distances by a factor of 4.
Of course, the simplest would just be to have the planet orbiting the star orbiting the BH....
Answer: Quasi satellites can get very close and very far from its host, essentially acting like an eccentric orbit. However, I am not quite sure if they have a simple periodic movement. My guess would be a more erratic movement, thus unpredictable seasons. Additionally, this type of orbital mechanics would cause the spin of the planet affected. Not just these, there would be a lot strangeness in that planet.
For habitability, it is possible to have life on the planet, but it would probably be under the seas as the temperature difference on the surface would be too high. If you set the position of the planet right, it would have liquid water.
Comment: it would be great to see some sources on this
Comment: As of now, there are no detected quasi planets. I couldn't find any theoretical insights written by an astrophysicist. However, I used the article referenced in the question to base my answer. These erratic behaviour are caused by the "dance" of two bodies as the larger constantly pulls and pushes the other.

Is "quasi planet" habitable for life?


Cargo aircraft temperature

Question: What is the temperature in the storage compartment on board of a cargo aircraft? I'm ordering a temperature-sensitive package by airmail and wouldn't want it to freeze.
There are many questions related to temperature of the luggage compartment on a passenger airplane but I didn't find anything about cargo-only aircrats.
Comment: Good question, but the answer should be found in the duplicate question linked by @Federico.
Comment: Temperature sensitive items MUST be in protective packaging. Although most things make it through without freezing I've seen some things, usually flowers, get damaged by freezing temperatures because there was only a thin piece of cardboard to insulate them. The aircraft is not the only place where it can be exposed to hot or cold temperatures. One of the more common temperature sensitive items shipped is medication. It is usually packaged in styrofoam containers to protect it from freezing.
Answer: Many things including bottles containing liquids break when the temperature drops below zero, so the cargo hold is always maintained above freezing; 7°C is typical (source).  This applies to both pure cargo aircraft and mixed passenger/cargo airplanes.
That said, it's harder to control for (say) cargo sitting around on tarmac while waiting to be loaded on the plane.  Your cargo shipper can likely arrange temperature-controlled shipping for you, but at a steep extra cost, and this is usually meant for perishables where the main danger is heat, not cold.  But unless you're shipping something to/from Siberia, you'll likely be fine.
Answer: Temperature conditions in cargo planes are no different than passenger planes.  Interior spaces are heated to some degree, as outside temperatures at 35,000 feet are too cold and could damage all kinds of cargo if allowed to stay that low.  When they are carrying live cargo then that cargo is placed in a section of the aircraft that is heated to a warmer temperature to assure that cargo arrives alive.
Answer: One more thing you should be aware of, pilots are given the cargo manifest by the load master before the flight. Sometimes, the cargo contains temperature sensitive loads and thus the crew can adjust the temperature of the cargo hold.
This holds true for cargo and passenger aircraft.
For example, if transporting live animals the temperature is increased above the "normal" range.
If your item is suitably marked and you have notified the shipper of the same, they will ensure that it is secure during the flight. However, as mentioned by @jpatokal - your main worry would be the time it spends on the ground, being driven to-from the cargo hold, etc rather than the flight on the aircraft.
Check with your shipper to see what they can do to prevent any damage to your item.

Cargo aircraft temperature


What should I do with fuel drained from the sumps during preflighting?

Question: What should one do when done sumping a small amount of fuel during a pre-flight?  Should it be dumped on the ramp? Or is it considered necessary to find the container far away from the airplane? Is it considered safe to dump it right back into the plane if it is uncontaminated?
Comment: I'm glad you asked this question. It never occurred to me dumping it on the ramp isn't the "right method." Honestly. That's what my instructors did.
Comment: @Jason my instructor even showed me the proper flinging technique to spread it out over a large area.  The second option was to find weeds growing in the cracks on the ramp and pour it on them to kill them.
Answer: The FAA issued an Aviation Safety Program publication called All About Fuel which talks about fuel preflight, including sumping fuel.  It contains the following:

Preflight Action     As pilot in command, you have the responsibility to determine that your aircraft is properly serviced.
  Check your aircraft before each flight and be sure you have the
  correct type of fuel. This practice may save your life! Take the time
  to inspect your aircraft thoroughly. Good preflight procedures:

Be sure all of the fuel and oil tank caps and covers are installed and secured properly after you visually check the fluid level.
Observe the color and odor of the fuel as you check the tank.
Draw a generous sample of fuel from each sump and screen drain into a transparent container. Check for the presence of water, dirt, rust
  or other contaminants. Unless you have the proper kind of fuel tester
  (e.g., GATS jar with intact fuel strainer), do not attempt to save the
  fuel drained from the sumps by pouring it back into the tank. Note: If
  you are not equipped to safely pour the drained fuel back into the
  tank, please be sure to dispose of it in accordance with EPA
  regulation.
Check that each fuel tank vent is clear of restrictions; i.e., dirt, ice, snow, bent or pinched tubes, etc.

Any FBO that sells fuel should have a way to dispose of it.  Some of them make it more obvious than others by putting sump barrels out on the ramp, but ask them what to do with it before you go out to the airplane and they should be able to help you out.  For environmental reasons, you definitely shouldn't dump it on the ground, because even if it does evaporate, it will come down somewhere.  At some airports you can even get in a lot of trouble (and have to pay a big fine) by dumping fuel on the ramp.  Don't take a chance!
Answer: Personally, I have a gas powered tug to pull/push my plane with. My tug is only certified for mogas, but I pour all of my avgas samples into it... I've never had to fuel it any other way.
Comment: @DavidWihl: Using leaded fuel in an engine rated for unleaded one is _not_ though, because it damages the catalytic converter.
Comment: Lawn mowers don't (yet) have catalytic converters
Comment: Agreed. Using higher octave fuel in an engine rated for lower octane is always ok, so 100LL in a mogas 89 octane engine is fine.
Answer: You should dispose of it in a fuel disposal container, if your airport has them (and many states require it). Barring that, the best option is a type of fuel strainer called a GATS jar that has a built-in filter to catch any particulates. If you pull a sample in a GATS jar that comes back "dry" you just unscrew the filter and put it back in the tank.
If you pull water, you should dispose of it in a way that doesn't involve dumping it on the ground. Either put it in a disposal container (lobby your airport or FBO to install them if they don't exist) or your own labeled gas can and use it for your lawnmower or something.
If you have no other option, try to avoid pouring it in a puddle on the ground. Toss it in an arc so it covers a large area and can evaporate as quickly as possible
Comment: Used properly the GATS jars will filter out any particulates or water that got pulled in the fuel sample (they do work, but it can be tricky to get the screen soaked in avgas before pouring the sample back).
Answer: I always put it back in the tank if it's not contaminated. Even if it is I'll put as much as I can back in. A few millimeters of water is not going to do anything when it would take almost a gallon of it just to reach the fuel pickup.
As for dumping, I've heard the EPA has been known to watch airports with heavy flight activity. They'll write your tail number down and send you a fine. Some states don't have any laws about it, though. I would save all the fuel I could, honestly. You can filter out uncontaminated fuel and reuse it. I know that's not really plausible if you're not in a hangar, though.


Small red see through worms in houseplants

Question: I bought a plant off of Facebook Marketplace and when I went to give it a watering these small red see through worms were sitting in the watering tray. I've watered the plant a few more times since then and I continue to get the small worms after every watering the only difference now is they get smaller in size with each watering. If you have any advice or know what they are that would help thank you!
Comment: Its a type of earthworm known as a brandling, usually present in compost heaps or where things are rotting, probably present and breeding in the soil in the pot.  Is the plant otherwise healthy, and what is it? Or post a photo
Answer: Looks like an ordinary earthworm; I am sure I have some in my pots, I don't find them to be a problem.


Six year old boy screams

Question: I have a six year old old grandnephew who when he gets mad screams at the top of his lungs and when he crys  about something he somehow can move it up a couple of octaves.  I want to smack him.  I don't.  I have tried ignoring it, threatened him and I've asked what is wrong?  That makes it worse.  Most of the time it is his fault for his brother's retaliations.  This is a daily problem.
Comment: Can you clarify the situation?  For example, where are his parents when this happens, and how do they react?
Comment: Probably not the exact best to smack him. It will teach him that smacking the parents back is possible.
Answer: I have no experience with this but I'll try to give advice.
Screaming is a symptom of a concern, and you need to find out what it is. Punishing him may eventually get him to stop screaming, but it won't help because the anger will still build up and cause trouble later.
When he's not screaming, try asking him in a friendly way something like "Hey, what were you so mad about yesterday?" and try to work things out with him.
Answer: I could type a really long answer full of everything psychology and parenting experts would say, but what it boils down to is: this child is in need of a connection. He needs empathy and respect. He needs you to treat him like you would your best friend if she were hysterical about something. Be calm, gentle and supportive. Put words to his feelings, since he obviously can't. Let him know you're here to talk when he needs. Children who feel like they haven't been given a voice will scream because they have no other way of expressing their feelings. It's the same reason babies cry - they can't talk, but they have needs and they need to get the attention of their caregivers. Older kids are just much louder.
I highly recommend checking out some parenting resources on positive parenting and focusing on how to empathize and communicate his feelings to him so that he can put words to his emotions. Overcommunication is the key with young children as they still don't have the tools they need to understand everything that happens to and around them.
Answer: I understand your concern.
Are the parents equally concerned?
I'd try whispering, redirection and praise for good behaviour.
Most children who do not know us well, are slightly afraid because they don't know what you'll do in the face of unwanted behaviours. I'd always fall back on: 1) support the parent. (I will assume they are perfectly good parents.) 2) talk in a quiet and calm voice. 3) remove anyone unnecessary to the situation from the area. 4) offer an alternative activity like dancing, singing, another toy, a walk...
Answer: If I understood right, the trigger for these screams has to do with sibling conflicts.  A great book for understanding and working on sibling conflicts is Siblings Without Rivalry: How to Help Your Children Live Together So You Can Live Too by Faber and Mazlish.
I recommend watching the two children carefully, so you can intervene and model some more effective ways of dealing with sibling conflicts.  Hopefully before the scream starts.
At your grand-nephew's age you may also establish a rule about screaming.

Six year old boy screams


Need to add a sub panel

Question: Moved here a few months ago and the heat pump is junk. It has a 100 amp breaker out of the main box. Thought about putting in a sub panel off of this breaker. Looked at the wire and it is a 3 wire (hot hot ground) and not a 4 wire (hot hot neutral ground). Not a pro sorry for the weird wording. Would I just connect the 2 hots to the sub and the ground to the bar and that's it or would this be a problem?
Comment: We need more information. Give us a run-down from the time it leaves the transformer till it gets to the panel in question.  Then what do you want to do with it?
Comment: What is the voltage of the loads you plan to run off the subpanel?  To put it another way,  now much of them are 120V?
Comment: Is the existing run a cable or wires in conduit?
Comment: Yes feeding a sub panel with just 3 wires is a big unsafe problem. You can't do it.  (Electrically yes, you can make some unsafe connections that appear to work, and are also UNSAFE)
Comment: What will be accomplished by feeding the heat pump through a subpanel?
Answer: Is it really ground?
Look closer.  Some cables, that wire can be used for either neutral or ground.  If so, ask your AHJ whether they will authorize to re-classify it as neutral and retrofit an actual ground.  The best plan is to ask your local AHJ if they are comfortable with that.  You can't retrofit neutrals, but you can retrofit grounds.
If you don't get AHJ permission, you will get a very, very rude and expensive surprise when you sell the house.
All subpanels must be fed with entirely separate neutrals and grounds.  Avoiding this is out of the question.  But you don't need neutral for 240V-only loads.  All your heat-pump loads are 240V, that's why neutral was never run in the first place!
Is it really 120V/240V?
If it's a subpanel for the heat pump, then it's very likely that every single load is 240V, with no 120V or 120/240V loads present.
In that case, install a 240V-only panel.  Use a subpanel of your preference, get lots of spaces because every breaker will need 2 spaces, install a ground bar, remove the ground-neutral strap since it is a subpanel, and connect nothing to the neutral bar, it will simply float.  Then you install your usual 240V breakers - a 20/30 for the heat pump proper, 30/40/50/70A for the emergency heat, etc.
Label the panel very clearly "240V only" so some future handyman or HVAC tech doesn't lose his mind or do something stupid.
You could make it a 120/240 subpanel later by running a new main cable.
Oh, but I need a little 120V too
First, try changing your loads to 240V.  Motors can be had easily either way. It's easy to get modern lighting that happily runs on 120-277V, 240V being within that range.  Old sodium/mercury/halide lighting often has transformer jumpers for that.
Second, OK, you really need 120V. How much?  For loads up to 1200 watts, obtain a 1.5KVA transformer, or forget that, just bring a branch over from your main panel.  For loads up to 4000 watts, obtain a 5 KVA transformer used on Craigslist, typically $100.  Feed the transformer 240V primary from a 240V dedicated circuit (so you can turn it off).  Feed the 120V secondary to a tiny 30-space* subpanel with both 120V rails jumpered together. Fit your 120V circuits.
If you really need more than 4000 watts of 120V at that location, knuckle down and replace that heavy cable with /3+ground cable.  And get aluminum - the lugs are aluminum and this will reduce corrosion, also it's far cheaper.

* That's an inside joke.  I am one of several here who recommend rather large panels, so you avoid the major hassle of running out of space.  Feeding a 1.5KVA transformer a 2-space panel is plenty, from a 5KVA, a 4-space panel will suffice.

Need to add a sub panel


Tax on Money transfered to India from UK?

Question: I'm from India came to UK on Feb 4th  2014 and I will be in UK till Sept 30th 2014. I'm earning money in Pounds, and paying tax as per UK tax policy. I could save some money which I transferred to savings accounts in India.
Now,
1. Do I need declare this transferred amount as other income in while tax return filing
2. or is this amount tax free? or how much is it taxable?
Answer: By earning money, I assume you are being paid a salary [and not allowance] in UK.
For the Financial Year 2013-2014: You are still a tax resident in India. India taxes Global income. Hence your salary from 4th Feb to 31st March, needs to be declared as Income. The tax will be at your total tax brackets. India does have a Double Tax Avoidance Treaty [DTAA] with UK, so you can deduct any taxes you paid on this income and pay balance in India.
Please note that it is not relevant whether you transfer money to India or keep in UK, it does not change the taxability.
For the financial Year 2014-2015: Depending on the exact date, you may or may not be a NRI [away for more than 182 days] for tax purposes. If you are an NRI there no tax, else as above para.
Answer: Since you have already paid tax to the Government of Uk, no tax will be levied on the money earned outside India. As per the Income tax act, any income received in India in all cases is taxable irrespective of the tax payer's residential status. A NRI after receiving income from outside India cannot be taxed as income because of remittance of such income to India.


How long can ATC operate for without main power?

Question: This question pertains to large towers at large airports. I'm assuming there is backup power in case of a power cut / power failure. But how long does a typical reserve generator / unit supply power for and what happens if it runs out without a main supply back online?
Comment: @FreeMan Do you mean VFR & VMC, rather than IFR & IMC?
Comment: I'm not sure it's clear what you're asking. Generators run on fossil fuels, so I guess they'll keep running until we run out of fossil fuel to use?
Comment: @RalphJ umm... yeah... that's the ticket...  _:blush:_
Comment: Remember, too, that if ATC goes out a a specific airport, all operations revert to IFR, so the airport doesn't _technically_ have to close (assuming the weather remains IMC). Anything in the air that can't land will divert. Additionally, in the US (or anywhere American troops are stationed), there will be mobile military units that could be moved into position to provide service/assistance if necessary for more long-term solutions.
Answer: Nearly all generators designed to serve as a backup power source in a safety critical environment (Hospitals, Air Traffic etc) will be designed to run 24/7 "indefinitely" with hot refuelling.
Obviously there will be a real world practical limit to that, but it will be many days if not even weeks potentially depending on the generator.
I suspect there will be huge variation in the type of standby equipment available, pre-loaded fuel and so on depending on the mission. For example, it would be entirely possible to have two generators which can switch over - allowing the other to be serviced and maintained.*
*NB: I don't know if this is an actual "thing", but I'd expect it in certain circumstances, for example, military.
Comment: @FreeMan, the local hospital, closest to the airport, has six multi-megawatt generators which provide basic power to the hospital, and full power to selected parts of the hospitals.  They test the gensets daily, and replace the units about every six years.  Buying one of those gensets is a sweet acquisition.  The gensets are configured so there can always be one or more offline for service.
Comment: Military, hospitals, yeah - I'm sure they've got backup backup generators. I'd imagine that hospitals, at least, probably have agreements/contracts with local equipment rental places to get generators onsite quickly should the need arise.
Comment: @FreeMan Yep, I actually saw a TV show here in the UK that had a backup generator being given a police escort. The hospital had power etc, but it was still given priority due to a lack of redundancy.
Comment: If anyone is truly interested, the UK AIP textual data for an airport gives the time in seconds to switchover to a backup power supply. I think the quickest I've seen has been "Less than 1 second". I'm sure this data is also available in every other country's AIP.
Comment: In addition, another backup feature for critical activities is to fed buildings using dual power sources, coming from two grid locations with distribution lines routed through different paths.
Answer: A nearby ATC facility I am familiar with has a backup generator which will run their ATC functions (TRACON and Tower), and is fueled to run for 4 to 5 days.  After that time, it needs more fuel.  After two weeks, it needs periodic maintenance (oil change, etc.).
The on airport approach radar has a separate generator at the radar site, which can run for about three days before needing refueling.
The airport has several backup generators.  The ones which run the airport lighting are not capable of running all the airport lighting, and do not power the beacon which is at a perimeter of the airport and without backup power. I do not know how long the airport lighting can be operated.
Some of the NAVAIDs have migrated off backup power.
The terminal building has several generators, and I do not know what their duration or backup coverage is, but I would guess they can partially run the passenger terminal for a day or so.
Various FBOs, corporate hangers and freight operations have their own backup power. My employer has enough fuel and generator capacity to run for one week, prior to needing refueling.  The A&Ps handle generator maintenance, but there is only one powerplant, so servicing, such as oil changes would happen most likely during daylight hours, by the A&Ps.  I cannot address the other operations.
The FAA FSDO office is on backup power for the office.
One problem with backup power is that it does not assure backup communications.  So in the case of businesses, they may loose connectivity.  Some of the ATC communications have service levels to include communications even with widespread power outages.
In 1992, power was lost at much of the airport for 3 days or more, and some of the gensets were updated after that outage.  My understanding is that even ATC backup power is not standardized for all facilities.
When the generators run out of fuel, they typically shutdown.  Often longer outages are due to weather or natural events.  In those cases, there may not be the ability to get a fuel truck in to deliver generator fuel.
Addendum: Talked with one of the tech who works on a company genset.  He says that they do not use natural gas because the supply might be disturbed with earthquake action.  They all use diesel.  The company genset was trial run on Jet-A but diesel is cheaper, and they have contracts with two suppliers.  If the tankers can get to the airport, the loaders can cut a path to the gensets (in snow).  Gensets vary but generally expect to shutdown every 100 to 500 hours for fluid and filter change.  For larger industrial backup gensets, filing the tanks can be done while running. The genset he oversees has a 10,000 USgal tank plus 500 gal in the genset housing.  Systems for places like Alaska have more complex fuel temperature management to avoid fuel wax precipitation. Larger enterprises, like the regional hospital down the street, use multiple gensets to permit servicing, and to provide higher availability statistics.
Comment: Wow, awesome , thanks so much for going out of your way to find that out... it's a shame about the diesel though.. not very environmentally conscious I guess :/


Does a higher sample rate compensate for quantization errors from higher gain?

Question: While normally bit depth would be associated with a more accurate signal to avoid quantization noise, I am wondering if recording at a higher sample rate will allow a more accurate interpolation of digital volume increases in post processing to avoid reduce this noise.
Answer: Short answer: no.  At the limit of converter precision, the error is not correlated well enough with the residual signal to provide reliable dithering.  That only makes sense when using converters below their available accuracy (why would you do that?).  When reducing precision by some sigma-delta kind of conversion not at the limit of its accuracy, higher rates may indeed recover relevant data through low-pass filtering an oversampled data set
The yield is quite less than using the conversion circuitry at its nominal precision, however.  So there isn't really much to be gained unless the data depth has been reduced before transmission by some process that you have some insight into and the actual precision to which the data is correlated with the available readings is higher than the nominal precision.


Resizing a Single Control In WinForms

Question: How might I design a UI in C#/WinForms which happens to contain several different control types such that only the ListView control gets resized if the user resizes the window?
Answer: There are two primary ways to make a control automatically resize based on size changes of the parent container (a Form in your case):

Set the Dock property of the control to DockStyle.Fill.
Set the Anchor property to "Top, Bottom, Left, Right"

Use the Dock property with Dock.Fill
The advantage of this method is that it takes the entire control and tells it to always fill the entire client area of the parent container (in your case, the Form client area). That's useful if you want to do something like fill a Form with a ListControl or TreeView or something like that. But it's not as useful if you want to scale a single control while using other controls (as you indicate is your need). In that case, you would need to set the Dock property on those other controls to DockStyle.Top or DockStyle.Bottom to have them float above or below your main resizing control.
That's a hassle and it also limits the layout options of the other controls. You can mitigate that problem by docking two Panel controls, one at the top and another at the bottom of the Form. Those panels will remain in fixed positions while the middle area (with your DockStyle.Fill control) scales with the parent Form. You can then put any controls in any layout configuration in those "header" and "footer" panels.
This kind of composite form-building using docked panels is incredibly powerful. Quite frankly, it was game changing in .NET when they introduced this with .NET 1.0 WinForms.
Use the Anchor property with "Top, Bottom, Left, Right"
If all you want to do is have a single control on a form scale, while others stay "stuck" to the edges, use the Anchor property. For the controls that you want to stay at the top, set the Anchor property to "Top, Left" (the default). For controls that you want to stay at the bottom, set the Anchor property to "Bottom, Left". For controls that you want to grow in width with the form/dialog (such as a single-line textbox control), set the Anchor property to "Left, Right" (and set Top or Bottom depending whether you want it move as the top or the bottom of the dialog changes.
And if you want a control to resize in all directions with a Form, set the Anchor property to "Top, Left, Bottom, Right". Very useful for "main control" type of things, such as a dominant listbox, tree control, or multi-line textbox.
For what you need, don't mess with the AutoSize or AutoSizeMode... those properties control how a control changes size based on its own contents, not how it resizes based on its container's behavior. Think of AutoSize/AutoSize mode as inward looking, while Anchor/Dock are outward looking. You get some very bizarre behavior if you use both sizing methods at the same time. Generally not useful.
Answer: Dock the ListView to all four sides of the form, and the other controls to 2 or less.
Answer: There is a property on controls called "Anchor" (in "Layout" category) if you set this to "Top, Bottom, Left, Right" it will maintain margins between control and its parent container causing it to resize as container changes size.
But if only one of anchors along one axis is enabled (e.g. "left", but not "right") it will move the control instead, again, preserving locked margins between the control and its container.
In short : exactly what James said, except it is "Anchor" not "Dock" property. Dock is similar but not exactly the same.
Answer: IF you put the ListView in one panel of a SplitContainer and put the remaining controls in the other panel you can restrict the growth of the second panel by setting the min and maxsize.
If your ListView is docked Full then it'll take all the increase when the form is resized.
Comment: This kind of works, except at a certain point while resizing the window, there are overlapping controls.
Answer: What if we have multiple controls in the form?
For example: If a form is used to generate some result in a grid with respect to the data entered in couple of text-boxes or combo-boxes, etc.;
And we want them to resize/realign accordingly and not overlap each other (as it happens when using the dock-fill), especially with the grid-view or similar control in context.

Resizing a Single Control In WinForms


How do 尤's 2021 meanings appertain to 尢?

Question: I can't read Chinese, and don't understand CUHK.  How does 尢 († lame; crippled) relate to 尤 (especially, particularly)? Yellowbridge.
Comment: Uhh...that Yellowbridge entry is confusing, 尢 is not a functional component of 尤, it is a shape that happens to share the same form as the part of 尤 without the dot. That dictionary doesn't have clear entries...
Answer: 尢 and 尤 are not related at all.
尢 is a crippled man with deformed legs as contrasted with the man in 大 having straight legs. Thus it means lame or crippled.
This character is no longer used in modern scripture and is written as 尪 with an additional 王 phonetic component.
尤 is possibly a variant form of hand 又 with an extra stroke probably representing a wound or wart which later became 疣.
Origins for 尤 is unclear to me though, but 又 is definitely a part of 尤.


Life and why we (mankind ) exist

Question: I'm stuck on this for now ...does the Buddha say anything about why we exist ( mankind ? I know how much he stated about reasons why we should not exist such as Nirvana being the highest goal to escape from the karma bond!! Just like to know for balance of reality.
Comment: this not an anwser but my point of view. let's say that happiness exist because suffering exist. and by observing the suffering we are bound to observe the happiness. it's a quest.
Answer: The main point of paṭiccasamuppāda pretty much comes down to: "if this exists, that exists; if this ceases to exist, that also ceases to exist". And so the reason to our existence, not just mankind but pretty much all conditioned phenomena is that the condition or the root cause for that existence still exists. So in our particular case, the reason we, mankind, still exists is because the conditions to our existence, the 3 unwholesome roots of greed, hatred, and ignorance, still exist. And as long as one has not completely uprooted them, s/he will continue to wander in Samsara's 6 realms of existence.
Comment: Sameasu, shouldn't be too strange. A car can only keep going if there's still fuel. A fire can only keep burning if there's still oxygen. A person can only keep getting reborn if there's still kamma driven by the 3 unwholesome roots.
SankhaKulathantille, 31 is not the only classification. Depends on how one wants to slice and dice the realms: could be 3 (sense-desire, form, and formless), or 6 (hell, affliced spirits, animal, human, asuras, deva), or 31...
Comment: So in a coconut shell  if all the conditioned phenonminon were to uproot  negative stimulus ..greed ..anger so forth then we would cease to exist,  strange !!
Comment: 31 realms. Not 6!
Answer: 'Existence' ('bhava') is a mental 'view' ('ditthi'). When the mind is free from 'self-view', 'existence' will cease. Instead, there will only be mental & physical 'elements' (dhatu) rather than 'existence'.

By & large, Kaccayana, this world is supported by (takes as its object) a polarity, that of existence & non-existence. But when one
  sees the origination of the world as it actually is with right
  discernment, 'non-existence' with reference to the world does not
  occur to one. When one sees the cessation of the world as it actually
  is with right discernment, 'existence' with reference to the world
  does not occur to one.
Kaccayanagotta Sutta

~~~

Why now do you assume 'a being'? Mara, have you grasped a view? This is a heap of sheer constructions: Here no being is found.
Vajira Sutta

In terms of 'physical life', this comes from the elements & from mother & father.

...this body composed of the four elements, born of mother & father, fed on rice & porridge...
Ganda Sutta

Life and why we (mankind ) exist


combinations from 2 hole card and 7 communal cards

Question: If we have 5 communal cards and 2 hole cards, and its our turn to deal, Can we just select all the 5 communal cards for hand? or do we need to keep our 2 hole cards and only choose 3 communal cards out of 5 communal cards to make a hand?
Answer: Well, it's actually pretty easy. In Texas Hold'em you can combine them anyway you want. So the answer is yes, you can choose all the 5 community cards to form your hand1.
In fact, in Texas Hold'em, the total number of ways you can combine the cards is:
(7!) / ((5!) x (7 - 5)!) = (6 x 7) / 2! = (6 x 7) / 2 = 42 / 2 = 21.
where n! = n factorial = 1 x 2 x 3 ... x n
When it comes to Omaha (the only other poker variation that has community cards), things are a little more complicated, since you have additional restrictions (2 cards from your hand, 3 from the community cards, NO EXCEPTIONS). I'm not going to present the calculation in the case of Omaha here (it's a bit longer), but if you're curious the result is 60.
1 = you probably lost the hand at that point, I suggest bluffing :D
Comment: there are actually a lot of poker variations besides TH and Omaha that uses community cards, although maybe those are the only two which are in widespread use in casinos...
Comment: @Michael Except for texas-holdem, omaha, omaha-hi-lo and recently 5-card-omaha, I've never heard of any other such variations. And I bet 99.9% of players are in the same situation.


Why my recent upvotes haven't changed my reputation?

Question: It is not that I loose sleep because of this, but I am curious. I posted an answer and it collected 4 upvotes yesterday, but my reputation hasn't changed. Am I missing something?
Answer: Presumably you are discussing your answer to How much of the universe is observable at visible wavelengths?.
What has happened is that you edited it so many times that it was automatically converted to a "community wiki" post. Note the different format of the user-card at the bottom right of the post:
The purpose of the automatic conversion feature is to (1) prevent the original poster for benefiting from a post that has been extensively edited by others and to discourage frivolous edits.
I'm going to de-wiki this one for you, but this is not something that you should count on happening again in the future. It is generally recommended that you work on your posts offline so that you will only make a few edits.
Comment: Thanks! Most of the edits are due to grammar corrections, or simple attempts to make the text easier to read, but I guess this time they were too many...


How can I make the milky way more apparent in my photos?

Question: I was using 6400 ISO with a f2.8, 28 mill lens with a .46 adaptor on a canon m50 for about 15" for this photo. I tried a 1.8 50 mill, 28 mill w/o adaptor, longer exposure, shorter exposure, higher/lower ISO but to no avail. I was wondering why the milky way is so hidden in these photos. I can barely see it but it runs vertically. Is it something I did during the photo taking? Or post-processing? Thank you guys.
Comment: Possibly light pollution from being in an urban area with street lights. You usually have to go out several hundred kilometres to get a decent photo of the Milky Way.
Comment: @Nayuki the shapeless red streaks in the photo make me think of airglow, which, if true, would mean the sky is quite unpolluted. OTOH, this could just be an artifact of noise reduction (in this case switching to grayscale would help seeing the actual information).
Comment: Don't you just need more exposure?
Answer: Using the Curves tool in your favorite image editor:
Answer: Amateur astronomer here. Most images of the Milky Way we see around are the results of multiple exposures combined in Photoshop or another image-editing software. However, it is indeed possible to get some nice single-shot images, but as xenoid pointed out, you'll need to play in the curves or otherwise enhance your image in postprocessing.
One thing I suggest you acquire is a light pollution–reduction filter. They are not very expensive (maybe $80 if I remember well, but you might find for cheaper on the second-hand market) and give good results at removing all the light that comes from human technology.
Comment: @Nayuki, until the rise of LED lamps in the past decade, the majority of light pollution came from low-pressure sodium lamps, so those filters were quite effective.
Comment: "removing all the light that comes from human technology" is an exaggeration. I imagine that spectrum filters can, at most, remove the two orange lines of sodium lights.
Comment: @Nayuki: Yes, I exaggerated, and I'm sorry about that. However, they remove more than just sodium spectral lines. Newer filters use a combination of coatings and isolate a few nebular spectral lines. They are **not** good for Milky Way pictures, but they are excellent for nebulas.
Answer: 'Photo stacking' is a method in which you take multiple images from the same orientation and location, and 'merge' them in post-processing. This enhances the starlight, and reduces the light pollution (very intuitive explanation, not scientifically complete).
Using this method enhances the images in a much better way.
You can still use post-processing to do all of this, but photo-stacking is much much better than this.
A wonderful tool for doing all of this is Sequator. It is specifically made for editing star images (Astrophotography), and has an option called 'Reduce Light Pollution'.

After that, simple contrast and saturation boosting gives you the desired results!
Comment: To correct the digital photos ([example](https://photographylife.com/night-sky-image-stacking) in the wild, or in an [urban setting](https://29a.ch/2017/06/22/urban-astrophotography)), [Siril](https://siril.org/) comes to mind as one (though not the only) program to perform the necessary correction of digital photos.
Comment: So the issue is that the camera software does not count photons for each pixel in a way suitable for deep sky images, and you use something else to do it?
Comment: @ThorbjørnRavnAndersen the point for adding several photos of intermediate length over one of the total is that then noise cancels out, single short duration upsets (satellites,...) only show in one and can be removed


Charging a 18650 battery using a 5V charger

Question: I built a power bank which had Seven 18650, savage some from laptop batteries and others from an old power bank... I recently just noticed that the power bank circuit won't charge the batteries  though the output process is good to go... It came to my knowledge that charging the batteries directly from the charger would severely damaged the batteries.. So I dropped the voltage using two diodes connected in series,  it gave me 4.0V, I don't need an ammeter to know that the diodes also took down the current,  because it took an hour and half to charge a 18650 from 2.8V to 3.2V meanwhile I'm using a 5V 1A charger... So any help on how to increase the current or any alternative to charge a 3.7V 18650 using a 5V 1A charger. Thank you in advance for your anticipation on getting me a solution..
Forgive my English,  its crappy.
Answer: ATTENTION! If you overcharge a lithium-ion cell it can explode and cause some serious damage. Also if you get the cell into undervoltage condition and try to charge it again it will explode too.
This is why lithium cells should never be used without a battery management system which supervises every cell condition.
Lithium cell should be charged with a CC-CV algorithm. Every cell is different about the end of charge voltage, under voltage border, maximum currents and so on. Without out knowing anything about the cell I would not risk burning down my house while experimenting with lithium-ion cells.
Mixing different cell types can also be dangerous because there can be compensations currents which are not intended.
(Source: I work at a company which develops battery management systems and builds battery packs. Even with a high experience we have burning cells from time to time for example when we get packs back from a customer and do not know what he has done with it.)
Answer: Designing battery charging system is a complex task with lot of precautions and calculations. That's the reason many battery management ICs are available in the market. The general features of such ICs are Charging type CC, CV or trickle charge mode, battery deep discharge protection, battery over charging protection, temperature monitoring while charging, etc.
These are the essential parameters which needs to be considered for designing battery charging circuit and any of these parameters going out of range may result in the explosion in the battery.
So, battery way is to search for good full featured Battery management IC and understand each of its parameters and their significance. Then you will be able to design a proper battery charging system for your power bank.
Also just by increasing the charging current by few hundred miliamperes will not give you desired results of fast charging. There is a certain limit of charging current depending on battery capacity, which needs to be follow in order to keep your battery healthy.