Is there a way to proactively vote against closure?

Question: The question H-NMR spectroscopy of [18]annulene presents an interesting problem in chemistry, and an even more interesting one for chemistry SE.  Three readers have voted to close the question but others would prefer to leave it open — and the latter seem powerless until after the question is first closed (whereupon five reopen votes are needed).  Is there any way to oppose question closure more proactively?
Comment: Regarding Ortho's "edit so it won't get closed", there are some triggers for experienced close voters that make them more likely to close something. When you're moderating (and not answering), you usually spend a few minutes for each thread and that might not be enough to get to the point, but seeing the post is two lines long, contains only one question, has grammatical or punctuation errors etc. would make you want to close it. In this case and most cases, commenting would've done the job.
Answer: Just going to rattle off a quick answer. There are a few ways. None of them will actively stop people from voting to close, but this is about as good as it gets.
Firstly, you can leave a comment, saying "I wouldn't close this because XYZ". Obviously, it helps if you substantiate this, e.g. the references I left might have convinced somebody that the problem is interesting enough to warrant journal articles being published on it.
Secondly, you can go into the close vote queue and click "leave open". If three people vote to leave open, the post will be removed from the close vote queue. It does not stop people from manually clicking on the question and voting to close, though.
Thirdly - and most ideally - you can edit the question into something that is less likely to be closed. I would have done this, but I'm busy, so in this specific case I offer my apologies. My comment seems to have done the trick, at least.
Comment: + You can (after two days have passed) bounty it. Questions with an active bounty cannot be closed (for the duration of the bounty and old votes may age away), and questions with a good answer are also less likely to be closed.
Comment: @Martin-マーチン Although, depending on the question, putting a bounty on it just to prevent closure is sometimes considered abuse. Probably not in this case, but it would be if the question would clearly have to be closed.
Comment: @wythagoras Indeed that would be abuse, which would need to be dealt with by us moderators. However, these are extremely rare cases.
Answer: Basically this is a rehash of Orthocresol's answer but coming from the background of the specific question and being one of the close voters, I can provide insight as to what would have swayed my decision in the other way.
The question as it was read like a little-effort do-my-homework question. It contained the information that the spectrum with just one peak was recorded at $\pu{100^\circ C}$. That, along with the little OP had written, made me immediately assume what the correct answer would be and also assume that OP could have found it with five seconds of thinking. Not having looked up any references or knowing the exact case in question I did not know I was wrong.

Ideally, someone would have come and edited the question. They could have included a reference to the articles and/or noted that thermally induced motion enough does not seem to explain the phenomenon because A, B and C.
Seeing this information in the question itself is the number one reason for me to take a step back and distrust my intuition. Seeing this being edited into the question after I voted to close is a way to make me retract the close vote.
If not that, a comment under the question would have been the next best solution. 'Hey, nice question, this is actually not as simple as it sounds. See here and here. I might post an answer later.'
This would not have helped if I have already voted but if I come across the question later I would maybe still hesitate and question my first impuls.
A bad solution would have been to just click leave open or to edit some grammar/wording from the review queue. That would not sway my decision.

Also, I contest your claim that the reopening force is stronger once the question is closed. It still only takes three who want to keep it closed in the review queue to make it drop out. Those users who go through the queue do so frequently and often vote on the questions to close to. They made up their mind earlier, so there has to be a substantial edit that sways them around. But this edit could have just as well been posted before closure if the question is as interesting as you imply. Therefore, no good is done by 'silently' clicking reopen.
Comment: 1. I don't get it. Why should someone edit the question to include stuff that should go into an answer? 2. Obviously you should have questioned your first impulse; evidently orthocresol's comment did not change your mind. Which is fine. 3. But that is how review queues work, and should work. And that is how three people disagreed with you.
Comment: @Martin-マーチン 1: Compare the following two questions: 'Why does cyclohexane only give one peak in proton NMR? Axial and equatorial protons should be different!' and 'Why does [18]annulene only give one peak in proton NMR at $\pu{100^\circ C}$? It has inside and outside protons!' If you do not consider question 1 a low-effect homework question, I agree to disagree. If not, I would ask you to explain why the two questions are fundamentally different.
Comment: 2. I don't think ortho's comment was there when I voted to close. In any case, I usually judge the quality of the question and less the comments added below. 3. I meant to say if I arrive in the review queue I cannot tell if people vote to leave open. So a better course of action is always to write out *why* leaving open is a good decision.
Comment: I just checked. I triggered the review process with the first close vote four minutes before ortho commented. (My comment was six minutes prior to his.)
Comment: Yeah, whatever, I misunderstood you. But then again I seem to misunderstand the community in recent times a lot. I don't want to go any deeper into the matter. It is apparent that we both have fundamentally different approaches on how to treat questions on this site; which is good, because only this way we have a discussion. However, I am too tired of doing that anymore.


SAO Kirito immortal in episodes 6 and 8?

Question: An Immortal object badge is shown in direct relation to Kirito's actions. What are these badges referring to? Was Kirito immortal?
Comment: i don't remember exactly what was in those episode but i assume it was referring to whatever he struck being an immortal object. ie it can't be destroyed
Comment: Pretty sure that includes that one time he punched a wall and the immortal object tag popped up
Comment: This occured twice: When Kirito fought a glitch in the game to get Yui, and when Kirito attacked Heathcliffe who was actually.... In both of those cases he went against rules that the game had in place. He himself was never immortal and actually almost died in both encounters.
Answer: You're likely thinking of the Immortal Objects which Kirito (and other characters) have been known to strike at.

In Sword Art Online, physical surroundings such as walls, buildings, monuments, and major features are considered "Immortal Objects". An error beep and a notification will sound if immortal physical objects are struck, even if by accident.

This doesn't change the state of the player's mortality - they are very much mortal - it only informs of the state of the object they want to interact with.  If it's an Immortal Object, it can't take any damage, so striking it (regardless of intent) will not cause harm to it.
Comment: Kayaba set himself up, so that his health couldn't go below half. When it finally did hit the half-way point, it displayed him as being "Immortal".
Comment: then when Kirito hit Kayaba , he got notification?


Why was Percy Weasley sorted into Gryffindor?

Question: He's determined, sure, but he doesn't exactly come across as particularly courageous or chivalrous. I know families tend to all fall into the same house, but of all the Weasleys we meet, Percy definitely seems the least Gryffindoresque. So why?
Comment: Much like Neville, Percy simply needed to grow up.  He eventually found his courage, just as Neville did.
Comment: Since when is being stooooopid and or poor decision making a barrier to being in Gryffindor?
Answer: As discussed before on this site, the Sorting Hat doesn't sort based on specific event(s) but on a person's potential (which is why it Gryffindored people like Neville "Timid" Longbottom, Hermione "Nerd" Granger and Peter "The traitor" Pettigrew).
As such, the fact that Percy joined the Battle of Hogwarts in the end shows that, as usual, the Hat wasn't wrong.

Percy: "Hello, Minister! Did I mention I'm resigning?"

Considering that he fought Augustus Rookwood and later Pius Thicknesse (who was a former head of DMLE and therefore a formidable opponent), he more than proved his bravery.
Additional considerations:

While he was a blithering idiot judgement wise, it did take courage to defy his family and stand with the Ministry. Would YOU risk the combined wrath of Molly Weasley, F&G twins, Charlie, Bill AND Ginny?
He's courteous (which is listed as one of the traits of Gryffindor) and, presumably, chivalrous to a degree though the latter isn't really explored in canon much.
Comment: plus he liked sneeking off and snogging girls in abandoned classrooms and hallways, bro was a player...
Comment: @HarryJohnston: Then again, even Ron was made prefect for no apparent reason except for being an important side character
Comment: I don't think it's entirely a matter of potential - he must have been more Gryffindorish in his school years than was explored in the books, or he wouldn't have been made a Prefect.
Comment: What does DMLE stand for?
Comment: @Anthony: "[Department of Magical Law Enforcement](http://harrypotter.wikia.com/wiki/Department_of_Magical_Law_Enforcement)."
Answer: Apologies about the lack of sources and links - I'll go back through and add them once I get home and can access the books/sites.
While I think @DVK's answer is good, I'd like to offer an alternate opinion.
Percy was sorted into Gryffindor because he chose to be in Gryffindor.  Both of his parents and his older brothers were in Gryffindor, and - presumably - probably several generations before that.  So he wanted to be there too.  There are several instances where the Sorting Hat takes the candidates choice into consideration.
The most obvious one is Harry himself, with his "Not Slytherin!".  It's also referenced that Hermione could easily have been in Ravenclaw, but due to her reading about the houses she preferred Gryffindor.
Neville Longbottom is an interesting counter-example, because I believe I read in Pottermore that he asked to not be in Hufflepuff, because he wasn't brave enough to be in Gryffindor.  But his reasoning wasn't sound - he showed his bravery throughout the books in many ways, large and small, and the Sorting Hat obviously could see his potential.
Comment: Re: "I believe I read in Pottermore that [Neville Longbottom] asked to **not** be in Hufflepuff": I think the "not" is a typo?
Comment: This is a nice idea, but it is just an opinion. I know you'll add supporting sources, but nowhere is it ever stated in any way that Percy asked to be in Gryffindor, this is all conjecture. And that's okay, in and of itself, (although you might like to signpost that), but I don't really see any need for it. I agree with DVK that there're plenty of reasons to put Percy in Gryffindor, so I don't think there's any need to suggest he asked to be in Gryffindor. And anyway I don't think it'd be a free choice, it won't sort you into a house you really don't fit into, all you can do is (sometimes) veto
Answer: Percy's driving feature is his sense of right and wrong.  His personal ambition (which might have sorted him into Slytherin), his critical thinking (which might have sorted him into Ravenclaw) and his sense of fair play and peacemaking (which might have sorted him into Hufflepuff) were all secondary elements to this core personality trait, and in many cases took a back seat to it.
That's not to say that he doesn't embody those things that would have fit him into the other houses, he clearly does in many respects.  The one we see the most evidence of is his ambition at the Ministry, but there's little evidence he would have started down that path if he had realized how wrong a position it would have put him in - indeed, once he realized the truth of what was going on, his shame at being on the wrong side greatly overpowered his ambition.
That's Gryffindor all the way.
Answer: Very simple. Because the author decided it shall be.
J. K. Rowling already KNEW how the entire series of books would play out and that required people to be in their places long before the final act was played out.
Comment: Thanks for your input.  This is what we call an "out-of-universe" answer: the author set things up in a certain way to fulfill the goals of the story. No one will argue against that.  But I believe that the original poster, SplittingAdam, is looking for an "in-universe" answer.  This means that, for the purpose of answering the question, we ignore that this work has an author who made certain decisions, and we ask ourselves if Percy being in Gryffindor makes sense from the point of view of the characters themselves, within the Potter universe.
Comment: Couldn't you answer *every* question about *any* fiction book book like that, though? Why did Voldemort try to kill Harry? Because the author decided it. Why was Harry a Wizard? Because the author decided that he would be. Etc. While that's technically true, it's not really useful.
Comment: For an answer that answer that gives J.K. R-Dawg so much credit, this answer doesn't give J.K. very much credit.
Comment: Fair enough.. the reason I brought it up is at times, that's the only answer that makes any kind of sense. In this particular case... it seems to be the only one that makes sense to me at least. It always felt to me like he didn't belong there.
Comment: When it becomes the ONLY possible reason that makes sense, then it is useful as a fallback reason to fall onto. It's also a clear sign of a plot hole to be found, possibly the size of a mac truck


Power required to run multiple appliances at once

Question: I have an electronics question. I am no electrician and am trying to build an alarm pi Mark2. Currently I have a 12v power supply running through a relay which the pi turns on and off to trigger my 12v RGB led strip. Along side this I have a standard micro usb powering the raspberry pi. What I would like to know is A) would it be possible to leech power from the 12v power supply using a t-joint solder into the power cable, and a 12v-5v buck converter, and still run both systems? Further to this, in the next generation of my project I would like to include a wireless charging dock and a set of USBs so that the Alarmpi could become an all in one bedside alarm and charge station. So B) how do I figure out the required power supply for 4 charging USBs, 1 5v qi mod, 1 5v pi cable and the 12v rgb leds? Please as for clarification if needed I know this is a little garbled but any advice would greatly help! Just to note the pi in turn will be running a 20x4 rgb LCD screen, 2 small adafruit speakers and an led clock screen as well as a luminosity sensor and a small amplifier
Answer:
A) would it be possible to leech power from the 12v power supply using a t-joint solder into the power cable, and a 12v-5v buck converter,

Yes, absolutely possible. However, it must be a switching mode DC-DC converter, linear regulators like the hearty 7805 have too much loss for this application

B) how do I figure out the required power supply for 4 charging USBs, 1 5v qi mod, 1 5v pi cable and the 12v rgb leds?

Add up their power by multiplying current draw x operating voltage
Simple Estimate, we will build the margin into the initial estimates

Raspberry Pi with Hat and peripherals 2A @ 5V = 10W
USB Charging 2A @ 5V = 10W x 4 = 40W

The unknown is the LED current, which you have not provided. However our simple estimate says we need about an extra 50W above the power consumption of the LED strip. 50W @ 12V ~ 4.25A , that is the extra current overhead you need from the 12V supply.
I would estimate that a reasonable LED strip is itself another 2A, so using typical grades I would pick a 10A @ 12V supply for your test. One such turnkey option for reasonable scratch is in the Mean-well series of power supplies (Vendor Link )
If you relax the charging requirements to 1A or fewer devices, or for your initial test, a 5A supply would probably work for most situations. But it will likely be starved if the lights are on and all four charging ports are bing used
Other Options
The problem with this setup is that you have quite a high current draw at your system supply voltage. This is probably reasonably OK for most users, but there are things to keep in mind, like the gauge of the wire used for the main supply hookup (at full current draw).
There are a few things to consider

Use a 24V voltage at a more reasonable 3-4A with two 12V LED strips in series with one another.
Use independent 12V and 5V supplies from the same mains plugs, turnkey switching supplies are cheap , reliable, and easy to use, this would guarantee your power needs.
Comment: Thank you for this it is fantastic, looking over this, I'm wondering, if I removed the USBs and, certainly for now, kept those separate, that would reduce the draw; USB Charging 2A @ 5V = 10W x 4 = 40W therefore I should be able to reduce the power supply right? The thing i'm aiming for is something with a fairly low power consumption which peaks only when in full use (the alarm going off, with the light on, whilst charging a phone and playing music! This is going to sound strange, but if you were to do this would you re-jig it and do it a different way to be more efficient? Thanks!!


Does the Finnish translative case exist in other languages?

Question: The Finnish translative case expresses the concept of becoming or turning into something else. Does this case exist in other languages, or is it unique to Finnish? How is this concept most commonly expressed in other inflected languages?
Comment: Note that translative is also used for path; some researchers also use the term "mutative" for "translative" as used in Finno-Ugric studies etc. For  more details see http://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199206476.001.0001/oxfordhb-9780199206476
Answer: The case is not unique to Finnish alone; its relatives, such as Estonian and Hungarian, have it too.
That said, it appears to be quite unique to the Finno-Ugric family, to which all of the above languages belong.
Answer: It is also present in Armenian language like:

հայ - hay - Armenian (for person/people/nation) --- հայերեն - hayeren - Armenian (for language)
հայերեն - hayeren - Armenian (for languagge) --- հայերենում - hayerenum - In Armenian (for language)
անգլիա - anglia - England --- անգլերեն - angleren - English

Am I understood right?
Comment: no, this not the case.
Comment: I know that fist and third one does not fit in but what about second one? This is not the case as well?
Comment: Is հայերենում a noun or is it an adverb? If it's adverb then -ւմ is not a case ending


Spilled coffee on laptop and matress

Question: Spilled coffee upon laptop & bed-sheet which has been absorbed into mattress too. Not only the bed-sheet but the mattress too has been stain due to spillage & seepage. Coffee is all over laptop keyboard too.
Comment: Sorry to hear that. What is your question?
Answer: First, unplug the laptop and remove the battery (or, it it's not removable, open the case and disconnect one wire from the battery). Also remove the clock battery. This prevents damage due to short-circuit and electrolytic corrosion.
Now, take the time to wash the spill from the laptop with distilled water. Remove the HDD and loudspeaker, if possible, but all other components can probably survive a dip in distilled water, though avoid water inside the display. After a water wash, wash with 90% or stronger alcohol (isopropyl or ethyl) a few times to remove the water.
Let the laptop air-dry thoroughly before reinstalling either battery and the power supply.
As for the mattress, blot with towels repeatedly, first wet and then dry. Any lingering smell of coffee should make it easier to get up in the morning.

Spilled coffee on laptop and matress


Show that the only function $f$ satisfying this property is the constant function $f(x) = a$

Question:
Let $f : (−1, 1) \rightarrow R $ be a continuous function with the property that
  $f(x) = f(x^4)$ for all $x$ and $f(\frac{1}{2}) = a$. Show that the only function $f$
  satisfying this property is the constant function $f(x) = a$.
Answer: We have $a=f(1/2)=f(1/2^4)=f(1/2^{16})$ and so on. So by continuity $f(0)=a$,
Suppose that $f(k)=b$ for some $k$ with $|k|\lt 1$. The same argument shows that $f(0)=b$.
Answer: Note that if $x\in I=(-1,1)$, then $x^4 \in I$. Since $f(x) = f(x^4)$, we have $f(x) = f(x^{4^n})$ for $n \in \mathbb{N}$. Since $\lim_n x^{4^n} = 0$ and $f$ is continuous, we have $\lim_n f(x^{4^n}) = f(0)$. Hence $f(x) = f(0)$ for all $x \in I$. It follows that $f(x) = f(0) = f(\frac{1}{2})$.
Comment: Since $f(x)=f(0) \forall x$ , we conclude $f(x)$ is free from x.
Answer: HINT: Let $A_0=\left[\frac1{2^4},\frac12\right]$, $A_1=\left[\frac1{2^{16}},\frac1{2^4}\right]$, and in general
$$A_k=\left[\frac1{2^{4^{k+1}}},\frac1{2^{4^k}}\right]\;;$$
then $f[A_k]=f[A_0]$ for all $k\in\Bbb N$. Let $u=\max_{x\in A_0}f(x)$; then for each $k\in\Bbb N$ there is an $x_k\in A_k$ such that $f(x_k)=u$. Now $$f\left(\frac1{2^{4^k}}\right)=a$$
for each $k\in\Bbb N$, and the points $1/2^{4^k}$ converge to $0$, so by continuity $f(0)=a$. On the other hand, the points $x_k$ also converge to $0$, so by continuity $f(0)=u$, and we conclude that $u=a$. Essentially the same argument shows that $\min_{x\in A_0}f(x)=a$, so $f$ is constant on $\left[0,\frac12\right]$. It's not hard now to see that $f$ must in fact be constant on $[0,1]$, and since $(-x)^4=x^4$, that it's constant on $(-1,1)$.
Added: This is not the most efficient argument; I'll leave it partly because the technique may be useful in another setting and partly as an illustration of how it can pay to reexamine an argument to see whether it can be simplified. If one looks a little more closely at this argument, one may notice that it really just relies on the fact that if $x\in(-1,1)$, then the sequence $\left\langle x,x^4,\left(x^4\right)^4,\dots\right\rangle$ converges to $0$. At that point the simpler argument posted by André Nicolas and copper.hat quickly emerges.


Is there a way to auto-complete the open command in Terminal?

Question: I frequently use the open -a  command in Terminal to open applications via ssh. How do I make it auto-complete an application's name?
Comment: I guess a marginally quicker way would be to type out the full path (just go with me for a while here!!), e.g. `open -a /Applications/Textedit.app foo.txt` (I assume thats what you're trying to do). If you press Tab after the `/A` of `/Applications` and then Tab again after the `/Te` of `/Textedit.app` then that should autocomplete both parts for you as you go. Not ideal, I admit, but maybe a but better. This was using Bash.
Comment: What shell are you using?
Comment: You could also try following through the instructions at the end of this post: [brettterpstra.com/grabbing-a-mac-apps-icon-advanced-bash-usage-2](http://brettterpstra.com/grabbing-a-mac-apps-icon-advanced-bash-usage-2/)
Comment: @DanielBeck Bash.
Answer: _complete_open() {
        COMPREPLY=()
        local cur="${COMP_WORDS[$COMP_CWORD]}"
        local prev="${COMP_WORDS[COMP_CWORD-1]}"
        [[ "$cur" == -* || "$prev" != '-a' ]] && return
        apps="$(mdfind kMDItemKind==Application -onlyin /Applications -onlyin ~/Applications -onlyin /Developer -onlyin ~/Developer | grep -v '/.*/.*/.*/.*/' | sed -E 's|.*/||g;s|\.app$||g' | uniq)"$'Finder\nArchive Utility\nCharacterPalette\nKeyboardViewer'
        local IFS=$'\n'
        if [[ "${cur:0:1}" = '"' || "${cur:0:1}" = "'" ]]; then
            quote="${cur:0:1}"
            cur="${cur:1}"
        fi
        local found="$(grep -i "^$cur" <<< "$apps")"
        if [[ "$quote" == '"' ]]; then
            found="$(sed "s|^|\"|g;s|$|\"|g" <<< "$found")"
        elif [[ "$quote" == "'" ]]; then
            found="$(sed "s|^|'|g;s|$|'|g" <<< "$found")"
        else
            found="$(sed 's| |\\ |g' <<< "$found")"
        fi
        COMPREPLY=($found)
}

complete -o default -F _complete_open open

Third version, which should now both be case insensitive and work within quotes.
Comment: I couldn't get this to work with `DVD Player`. Any ideas what's wrong? Looks like a Tab instead of a space...
Comment: @DanielBeck It was missing `IFS=$'\n'`. Anyway, I edited the answer again.
Comment: Looks good. A late +1 for the `mdfind` idea. Nice work on the optimization and fixes. `CoreServices` are probably personal preference though. What's the reason for `nospace` though? If there's only 1 program, I want to continue right away with the filen to open. Just personal preference? Any idea about the remaining quoting issue? AFAICT, that's the only thing left for a proper solution.
Comment: @DanielBeck I always put the `-a` flag at the end, so I guess `-o nospace` is just a personal preference. Maybe we should ping Brett Terpstra or something to finish this nerdfest...
Comment: Thank you so much!! @DanielBeck you too. I chose Lri's version because of the speed. Unfortunately, yours was a bit slow. Thanks so much both of you! You've helped me a lot and made my Terminal speed increase.
Comment: Very handy trick! +1
Answer: Add the following to your .bash_profile or .bashrc and launch a new session:
function _complete_open {
    cur=$2
    COMPREPLY=( );

    [[ "$COMP_WORDS" = "open" ]] || return
    [[ "${COMP_WORDS[ $(( $COMP_CWORD - 1 )) ]}" = "-a" ]] || return

    OLDIFS="$IFS"
    IFS=$'\n'
    local _part="${COMP_WORDS[$COMP_CWORD]}"

    if [[ "${_part:0:1}" = '"' || "${_part:0:1}" = "'" ]] ; then
        COMPREPLY=( $( compgen -W "$( mdfind kMDItemKind==Application | sed -e 's|.*/||g' -e 's|.app$||' | sort -u )" -- $cur ) )
    else
        COMPREPLY=( $( compgen -W "$( mdfind kMDItemKind==Application | sed -e 's|.*/||g' -e 's|.app$||' -e 's| |\\\\ |g' | sort -u )" -- $cur ) )
    fi
    IFS="$OLDIFS"
}

complete -o default -F _complete_open open

No need to install anything. This works with bash out of the box.

It will only autocomplete program names if the previous option is -a and otherwise show default behavior, e.g. return a list of all files in the current directory or complete the current path prefix.
The results are generated from system_profiler SPApplicationsDataType, which is the easiest way to get all applications that can be launched this way on your system like that. The list is processed to only return the program names, which can contain spaces and can be different from the bundle names (even when ignoring .app suffix)
Usage: Type open -a, followed by a space, followed by pressing Tab or Esc (twice on my system, not sure if it's everywhere).
Example showing all the helper applications for my scanner:
$ open -a Scan
Scan to E-mail          Scan to Excel           Scan to Folder          Scan to Print           Scan to Searchable PDF  Scan to Word            ScanSnap Manager

Drawbacks and problems of this solution:

There are tons of programs on your system you might not be aware of, like everything in /System/Library/CoreServices. You might not want to list all of them. OTOH, it's really easy to see and launch e.g. CharacterPalette or KeyboardViewer this way. *Configure the mdfind call(s) appropriately with the -onlyin argument.
It's kind of slow, due to system_profiler SPApplicationsDataType. You might need to wait a second or two before completion shows up. Now uses mdfind to quickly get the programs. Thanks @Lri
It can handle spaces in application names, and quotation enclosed program names, but it's rather hacky. It requires the quote to be the first character: While Scan" to "P is valid in bash, this program will not detect it. Completion does not work after an escaped space either (e.g. Scan\ to), use quotation marks in such cases ("Scan to). Support for escaped spaces is only good to complete DVD to DVD\ Player.
Comment: Wouldn't `mdfind 'kMDItemKind==Application'` be faster? If `completion-ignore-case` is set on, grep should probably ignore case as well.
Comment: @Lri You're right. Couldn't find a case where these results would have made a difference.
Answer: Programmeable autocompletion to the rescue! Needed a lot of copying from the Bash Completion Homepage though, which is worth installing anyway for a lot of auto-completion magic. If you do, you will only need the last function (_open) and the initialising command from below.
Add the following to .bashrc:
# taken from http://bash-completion.alioth.debian.org/

_compopt_o_filenames()
{
    # We test for compopt availability first because directly invoking it on
    # bash < 4 at this point may cause terminal echo to be turned off for some
    # reason, see https://bugzilla.redhat.com/653669 for more info.
    type compopt &>/dev/null && compopt -o filenames 2>/dev/null || \
        compgen -f /non-existing-dir/ >/dev/null
}

_tilde() {
    local result=0
    # Does $1 start with tilde (~) and doesn't contain slash (/)?
    if [[ ${1:0:1} == "~" && $1 == ${1//\/} ]]; then
        _compopt_o_filenames
        # Try generate username completions
        COMPREPLY=( $( compgen -P '~' -u "${1#\~}" ) )
        result=${#COMPREPLY[@]}
    fi
    return $result
}

_quote_readline_by_ref()
{
    if [[ ${1:0:1} == "'" ]]; then
        if [[ ${BASH_VERSINFO[0]} -ge 4 ]]; then
            # Leave out first character
            printf -v $2 %s "${1:1}"
        else
            # Quote word, leaving out first character
            printf -v $2 %q "${1:1}"
            # Double-quote word (bash-3)
            printf -v $2 %q ${!2}
        fi
    elif [[ ${BASH_VERSINFO[0]} -le 3 && ${1:0:1} == '"' ]]; then
        printf -v $2 %q "${1:1}"
    else
        printf -v $2 %q "$1"
    fi

    # If result becomes quoted like this: $'string', re-evaluate in order to
    # drop the additional quoting.  See also: http://www.mail-archive.com/
    # email@example.com/msg01942.html
    [[ ${!2:0:1} == '$' ]] && eval $2=${!2}
} # _quote_readline_by_ref()

_filedir()
{
    local i IFS=$'\n' xspec

    _tilde "$cur" || return 0

    local -a toks
    local quoted tmp

    _quote_readline_by_ref "$cur" quoted
    toks=( ${toks[@]-} $(
        compgen -d -- "$quoted" | {
            while read -r tmp; do
                printf '%s\n' $tmp
            done
        }
    ))

    if [[ "$1" != -d ]]; then
        # Munge xspec to contain uppercase version too
        [[ ${BASH_VERSINFO[0]} -ge 4 ]] && \
            xspec=${1:+"!*.@($1|${1^^})"} || \
            xspec=${1:+"!*.@($1|$(printf %s $1 | tr '[:lower:]' '[:upper:]'))"}
        toks=( ${toks[@]-} $( compgen -f -X "$xspec" -- $quoted) )
    fi
    [ ${#toks[@]} -ne 0 ] && _compopt_o_filenames

    COMPREPLY=( "${COMPREPLY[@]}" "${toks[@]}" )
} # _filedir()

# only the following is needed if bash-autocompletion is already installed
_open ()
{
    local cur;

    cur=$2;

    COMPREPLY=();
    if [ $COMP_CWORD -eq 2 ]; then
        COMPREPLY=($(compgen -W "$(/bin/ls /Applications)" -- $cur ));
        return 0
    fi

    _filedir
}

complete -F _open open

Comment: Does not handle program names with spaces (like `DVD Player.app`). Lists directories in `/Applications` as well (like `iWork 09`, as separate entries `iWork` and `09`), but not the programs contained therein.
Comment: So I followed the install instructions and added the code to `.bashrc`. Now how do I get it to autocomplete? What do I push to autocomplete? (Sorry, I can't read the code)
Answer: This comes enabled by default with the Zsh shell, as long as you have completion itself enabled, of course. Zsh is included in OS X.
All you have to do is put autoload -Uz compinit; compinit in your ~/.zshrc, or enable completion through the first run configuration menu.
Zsh is actually mostly a superset of Bash, so you shouldn't have to learn anything new. Even your scripts will probably work!


Rigid foam board in walls between studs, plus fiberglass batt?

Question: I've got access to some discounted (factory seconds) of rigid foam board and looking to cut it up and place it against the exterior walls on the inside of an old (1894) converted house that is now four 1br apartments. Thinking of going with 1" of rigid foam board and then adding a fiberglass batt on the inside of that. With the old house, the 2x4 studs are actually at least 4", not 3.5.
It's in southern Illinois and I'm trying to get some good advice on whether I should be concerned about vapor barrier and if the fiberglass batt makes this better or worse?
Comment: The XPS (or EPS) acts as a vapor barrier. You dont want to add another one. You can do XPS, then batt insulation, just make sure the batt insulation is unfaced. See this Q&A for more details; http://diy.stackexchange.com/questions/8636/should-i-use-steel-or-wood-studs-for-basement-exterior-walls/8644#8644
Answer: I am doing exactly this, but the reason for the rigid foam is to create an air channel along the underside of the roof to allow airflow up to the ridge vent. The layering is, from the outside inwards, roof, 1 in. airspace, rigid foam, batts, vapor barrier (plastic), drywall.
Understand that the function of the vapor barrier is to prevent moisture from migrating from the warm side into the total thickness of insulation towards the cold side, where at some point the temperature gradient will drop enough to cause condensation. You do NOT want this to occur inside the insulation. The fact that the rigid foam is also a vapor barrier is not a problem as long as you have a correct barrier immediately behind the drywall.
If by "adding batt inside" you meant "inside the wall - towards the roof", then I would not rely on the rigid foam acting as a sufficient vapor barrier unless you made a point of carefully sealing all the edges with Acousiseal. Preventing air migration past the insulation is critical to its effectiveness, and you must also provided for ventilation of the roof material itself.
Answer: I would not put in rigid foam along with fiberglass batting just because you have access to some product cheap. You do not want to trap fiberglass between two vapor impermeable layers. The designs of insulation products have been arrived at by scientific principles and by trial and error. If you try to cobble something together, thinking you are going to get better results on the cheap, you are likely to make a mistake. It would be far better to have an incompletely filled cavity than trap moisture in the walls.
In a cold climate the kraft paper side of fiberglass bats is normally next to the interior drywall. This keeps the moisture generated inside the house from permeating the fiberglass where it would condense.
Answer: Well, it depends:

What is the thickness of your fiberglass insulation?

If you can use the foam board and fiberglass - without compressing the fiberglass batts, then I say go for it.
However, if you end up compressing the fiberglass then you will greatly lose the rated R-Value with an improper installation and almost certainly negate any possible benefits from the foam board. Poor insulation installation invites irritating inconsistencies in hot and cold spots within a room.
With regards to the vapor barrier, you should place a vapor barrier on the drywall side of the fiberglass insulation. (You can use insulation with kraft paper - which counts as a vapor barrier. Otherwise, you can use a thin sheet of plastic.) The vapor barrier keeps moisture out of the fiberglass so it doesn't saturate and effectively insulates.


proving if a number is prime or not using combinations

Question:
I am really confused on this problem. I am given that $p$ = prime number, $1 \leq k \leq p-1$, and am asked to show $\binom{p}{k}$ multiple of $p.$
How do I prove that $\binom{p}{k}$ is a multple of $p$?
Answer: Let $\dbinom{p}{k}=b$.
Then $p!=bk!(p-k)!$.
Note that $p$ divides $p!$ and is relatively prime to $k!(p-k)!$. For it is clear that $p$ cannot divide any number between $1$ and $k$, nor any number between $1$ and $p-k$. It follows that $p$ divides $b$.
Now show that if $p$ is not prime, then the result is not necessarily true. By the way, it is sometimes true: there are plenty of non-prime $p$, and $k$ with $0\lt k\lt p$, such that $p$ divides $\dbinom{p}{k}$.
But I think you are just required to give an example of a non-prime $p$, and a $k$ with $0\lt k\lt p$, such that $p$ does not divide $\dbinom{p}{k}$. A little fooling around will yield an example.
Remarks: $1.$ Here is a cute combinatorial proof of the result about primes. There is a circular table, with $p$ chairs symmetrically placed around the table.  There are $\dbinom{p}{k}$ ways to choose $k$ chairs for $k$ people to sit on. Call two choices equivalent if one can be obtained from the other by moving everybody counterclockwise by the same amount $a$, where $0\le a\le p-1$. Then every seating belongs to a unique equivalence class of size $p$. It follows that $p$ must divide the number of ways to seat the people.
$2.$ From the wording of the question, it is possible that you are supposed to show that for every non-prime $m\gt 1$, there is a $k$ with $0\lt k\lt m$ such that $\dbinom{m}{k}$ is not divisible by $m$. This takes some effort to prove.
Answer: Re: prove that this is not true if $p$ is not prime.
Well, it is (vacuously) true if $p=1$.
But if $p>1$ is not prime, let $q$ be a prime that divides $p$.  If $q^d$ is the highest power of $q$ that divides $p$, show that $q^d$ does not divide $p \choose q$.


How to securely store application data on mobile device

Question: How can security be enhanced to the maximum in a messaging app storing messaging history on the device (like whatsapp)?
I am specifically referring to methods to minimize the risk of the data being stolen in case the device is physically compromised or compromised using malware.
I know that whatsapp encrypt the file containing the chat history, nevertheless when you transfer this file between devices you can still open it up with whatsapp and read the contents. So what risk is this protection meant to mitigate?
I know that the filesystem restricts access so that only the application can access its files - that means that as long as the device isn't compromised, this information cannot be accessed by a malicious entity. Is this assumption correct?
I've seen in another thread that there is an ability to use the SIM card as a means of providing security - Securing data on a mobile device (even from the user/owner)?
Is this applicable in my scenario?
Answer: You would do it the same way you'd do it on a computer, but once the machine is compromised, all bets are off, and you're mostly wasting your time. You may check out this related question on which my answer suggests deriving a key from the hardware and using it to encrypt the sensitive data but even then, that only buys you more time until the attacker reverse-engineers how your app generates this key and generates the same one using his malware running on the same phone (thus having access to the same hardware).
An HSM may help in this case but if your app can get the data off the HSM, so can the attacker with root access to the machine. HSMs are only effective against data that isn't supposed to get off of them, like private keys (they're generated on the HSM, the HSM itself uses them to do crypto operations on data sent by the host machine but it never reveals the actual keys), but that isn't applicable in your case since you want to protect a message history which the user would want to read (ie, get back from the HSM).
Answer: I have read a post which clearly stated that Whatsapp messages can be easily retained. Whatsapp is not a secured messaging App. Follow these steps to secure your WhatsApp from getting hacked:

WhatsApp doesn't have a very secure server, so avoid using WhatsApp when on Wi-Fi.
Never share your IMEI number
Avoid keeping your phone out at places where it can be accessible to others.


What happens to the ISS waste?

Question: How is the waste managed on ISS?
I guess there are three main waste types: two human waste (liquid and solid) and various packaging for food and substances for experiments.
Are they recycled or sent to Earth or discarded in space?
Comment: Duplicate of [What happens to waste on the ISS?](https://space.stackexchange.com/questions/904/what-happens-to-waste-on-the-iss) and others.
Comment: What you can do is first search the site for the `iss` tag and the word "waste" and see what's been answered already. https://space.stackexchange.com/search?q=waste+%5Biss%5D Then if you can identify a *more specific question* that doesn't seem to be already answered, edit this post and ask that instead.
Answer: Urine is captured and on the Russian side of the house electrolyzed to make oxygen and the hydrogen vented.
Most other waste is packed into one of the departing capsules (Progress), HTV (Just retired, HTV-A to replace it), Cygnus, ATV (before it retired).  Dragon Cargo brings back useful things since it lands.
The rest burn up during reentry.
Answer: Urine is processed into water on both the US and Russian sides of the ISS.
Poop is bagged up and thrown away like other trash, which gets packed into logistic vehicles and burned up on entry.
Comment: Is the solid waste dehydrated or sterilized before it is bagged up?
Comment: Great followup question!
Comment: Best wishes! https://i.imgur.com/ibhRDmI.png
Comment: If nobody asks it and I remember to, I will. I'm currently trying to quit drinking coffee after 40+ years of several cups/day and I'm not much more than a semi-aware bag of protoplasm unable to remember its name. For some reason interacting with Stack Exchange is so deeply embedded in muscle memory that I'm still typing, so while I still appear active here, it's really a case of "the lights are on but nobody's home".

What happens to the ISS waste?


Why does the Tezos node use only one CPU core?

Question: I never see the Tezos node using more than CPU core even when syncing from scratch. Why is this? Is this the reason why the nodes takes forever to sync in archive mode? Are there any plans to make the node multi-threaded or more performant?
Answer: The performance of syncing an archive node depends on multiple factors including your hardware, network connectivity, number peers etc however one of the dominant one is the intensity of I/O operations not the number of computations by the CPU (see this question for instance). It is more likely that you would go faster by improving your storage from say hdd to ssd than by having the node go from single threaded to multithreaded.
To fasten up syncing there are several alternatives
1) use snapshots: see here and there for additional infos
2) use a different history mode : see this answer for more infos
Comment: Thanks for the information but this doesn't answer my questions about only a single CPU core being used.
Comment: @tezette the tezos node is single threaded afaik so it uses only 1 cpu core.
Comment: I am more interested in why and whether there's any plans to change it?
Comment: @tezette what makes you think its necessart for the node to be multithreaded ?
Comment: For the same benefits we get from multithreading any application on a modern processor.


Can we get mtg-autocard support for inside code blocks?

Question: Code blocks are often used on the site for the fixed-width indentation the provide. This answer attempted to use a mtg-autocard link inside the code block, but it didn't link. Would it be possible to enable the autocard link inside code blocks? (Or is there already a way to do it?)
Comment: I'll look into it, but I'm not sure this is fixable. The main purpose of a code block aside from formatting is that it ignores all other formatting characters (which is also why `**bolding** and *italicizing*` don't work in a code block). I'm not sure if it's possible to make an exception, but I'll poke around.
Answer: The workaround here is not to use code blocks for the indented list. If you use   to force non-code-formatted text to indent, Markdown will not start the count over.
Here's an example. This text:
1. **Albert** casts [mtg:Ancestral Recall]. [mtg:Ancestral Recall] Goes onto the stack.
  2. **Albert** wants to do nothing and implicitly (by sitting there doing nothing) passes priority
  3. **Nancy** gains priority and responds with [mtg:Counterspell]
    4. **Nancy** gains priority and implicitly passes by doing nothing.
    5. **Albert gains priority** and, looking smug, says "In response" and slaps his own [mtg:Counterspell] onto the table. Poor **Nancy**!

looks like:

Albert casts Ancestral Recall. Ancestral Recall Goes onto the stack.
  2. Albert wants to do nothing and implicitly (by sitting there doing nothing) passes priority
  3. Nancy gains priority and responds with Counterspell
    4. Nancy gains priority and implicitly passes by doing nothing.
    5. Albert gains priority and, looking smug, says "In response" and slaps his own Counterspell onto the table. Poor Nancy!
Comment: Thanks, Abby! I applied your formatting to the answer in question.
Answer: I feel like that's a formatting issue: that stuff does need to be arranged hierarchically neatly, but it shouldn't be in a code block. It's just that the list auto-formatter (which resets numbering with indentation) is getting in the way of how Rawrgamming wants to show the stack using indentation for the separate levels.


Why are there so many books in Suruga Monkey?

Question: In Suruga Monkey Part 2 of Bakemonogatari, Kanbaru's room is literally full of red hardcover books. Why is this and what does it represent?
Comment: Those are her piles and piles of boys love novels. They represent her massive fandom of boys love novels.
Comment: From the wiki: "Her hobbies include reading yaoi literature and playing basketball." http://bakemonogatari.wikia.com/wiki/Suruga_Kanbaru.
Comment: Pre sure she said she was into yuri as she's a lesbian, not yaoi.
Comment: @MaxLi she calls herself a Yuri after she upfront said to Araragi that she was a lesbian (same thing really), there's no reason a Yuri can't also be into reading Yaoi as well
Answer: That's her massive collection of BL (boys' love) books (which she is also into, besides considering herself a lesbian), at least that's what they represent. As many other things in Monogatari's animation, it should be taken more symbolically than literally. Take for example Senjougahara's "arsenal" of stationery in episode 1 of Bakemonogatari, or even more obviously the constantly shifting, multiplying, growing, falling etc. pile of pencils in episode 6 of Nisemonogatari (you'll know when you get there :) ).
Answer: I believe the books (which are from BL) can represent the mental state of the character, who is also homosexual. Maybe that's why it's all a mess, and when Araragi goes to Suruga's house during a long conversation, they arrange (literally and metaphorically) her books (feelings). Perhaps this is why, in the Nisemonogatari tidying scene, when Suruga gets confused in the conversation, the books fall into a domino effect, and when Araragi helps Suruga to find herself again, the books arrange themselves. But that's just my interpretation


Is it possible to get an RSA encryption key by comparing the unencrypted and encrypted file?

Question: Exactly what the title says. If I have a RSA encrypted file, and the exact same file but decrypted, can I tell the key that was used from that information?
Comment: One thing that you should consider is that in most real-world cryptosystems built on RSA, the public key of the recipient is explicitly included. So even if the "textbook" answer were "no", the answer in the real-world is almost assuredly "yes".
Comment: Are you sure you mean the encryption key and not the decryption key?
Comment: @SEJPM You might be able to find the public key, and that wouldn't be a problem in typical scenarios.
Comment: Ohhh, sorry I didn't read the question carefully enough D: You're asking to get the public and not the private key! I really have to apologize. Retrieving the public key from comparing encrypted and unencrypted is of course not a security threat.
Answer: No, if the RSA cryptosystem is secure, i.e. when it uses random padding such as PKCS#1 v1.5 padding or OAEP, then you cannot. As Stephen already mused, it is pretty likely that you can find out the key simply because it is included or can be derived; generally public keys are not meant to be secure.
If textbook (raw modular exponentiation) RSA is used then you can encrypt with the public key. If you get the same value then it is pretty likely that you've found the public key. But usually textbook RSA isn't used because it is insecure in several other ways as well. Ciphertext distinguishablity is just one of the problems.
Now some information can of course still be extracted from the ciphertext. First of all, the length of the RSA ciphertext is generally identical to the key size. So you can distinguish between keys of several lengths. Furthermore, if you find an RSA ciphertext that is higher than the modulus of the public key then that key is certainly not used to generate the ciphertext.

You explicitly asked for the encryption key which is the public key. If you meant the private decryption key then, no, the key cannot be derived except for the little amount of data also available for the public key.

Note that RSA is never directly used to encrypt files. Instead a hybrid cryptosystem needs to be used. The usual RSA schemes are not secure to encrypt data larger than the modulus minus the padding overhead. Furthermore, encrypting large amounts of data with RSA would be very CPU intensive and decrypting it would be worse.
Comment: Well the files in question are encrypted with RSA-256, and one 100kb file took about 5 minutes to decrypt. Of course this was through the attackers site (These files are on a PC hijacked by CryptoWall :/)
Comment: @aaro4130, CryptoWall seems to use RSA-2048 and AES-256, RSA-256 *could* be cracked.
Comment: @aaro4130 If it was that easy to circumvent the encryption used by CryptoWall you would have known about it.
Comment: Heh, I guess so
Answer: The ciphertext should look like a random element within 1 and the modulus (since it is a value from within that range as Yehuda Lindell pointed out). Without knowing the modulus it should not be feasible to distinguish two ciphertexts encrypted with different keys.
If the public key is stored in some key-database you could ofc try to encrypt the decrypted text with all stored keys and test if the encryption matches the text. Anyway, finding the private key is not yet possible in polynomial time with classic computers.
Update: Thx @Yehuda Lindell for the remark.
Comment: Actually, from two (plaintext, ciphertext) RSA pairs, you have a good chance of finding the public key. It's only the private key that can't be found in any decent cryptosystem.
Comment: This just is NOT correct. There is no requirement that a ciphertext be indistinguishable from random. It turns out to be true often in symmetric schemes and some people use this as a definition there for other reasons. However, it is NOT true for public-key schemes. An RSA or ElGamal or ECIES ciphertext does NOT at all look random.
Comment: Would i not have to find 'randomly' the according primes out of the key space? ...reducing the chance of finding such a number to the cardinality of the set of matching primes?
Answer: Some information about the RSA public key is revealed by the ciphertext. This is due to the fact that the ciphertext is a value between 1 and the modulus. Beyond this, I don't know what is revealed. However, what I can prove is that whatever you can learn from the plaintext and ciphertext together, you can learn from the ciphertext only.
I can prove this via a reduction (I'll just give a sketch here). Assume, by contradiction, that there exists an adversary $A$ who outputs "more information" about the RSA public key given the plaintext and ciphertext, than what is possible when just given the ciphertext (a bit more formally, there is some efficiently computable function $f$ of the public key that $A$ can output when given the plaintext and ciphertext but cannot output when given just the ciphertext). First, I would argue that if $A$ is given the ciphertext and a different random plaintext, then it can output $f(pk)$ with probability that is no greater than when given the ciphertext only. This is quite easy to see. Next, I construct an adversary $A'$ who attacks RSA in the CPA experiment. $A'$ outputs two random plaintexts $m_0,m_1$ and is given a ciphertext $c$ which is an encryption of one of them. Note that $A'$ also knows $pk$. Then, $A'$ runs $A$ on $c,m_0$. If $A$ returns $f(pk)$, then $A'$ outputs 0; otherwise it outputs a random bit. A probabilistic calculation here will give that $A'$ will output 0 when $c$ is an encryption of $m_0$ with probability non-negligibly greater than $1/2$.
Summary: whatever you can learn about the public-key from the plaintext and ciphertext, you can learn from the ciphertext only.
Caveat: All of the above needs a formal proof, so I'm only 98% sure that it will all go through.
Comment: Textbook RSA is not secure encryption. My proof is for something that is secure encryption. In any case, how do you know $N$ exactly?
Comment: Well, let's quickly assume textbook RSA. Assume you're given two messages $m_1,m_2$ and two  ciphertexts $c_1,c_2$. Now guess a value for $e$ (chances won't be too bad for $e<2^40$) and observe that $c\equiv m^e \pmod N$. Now use this to obtain the relation $m^e-c=rN$. Calculate the left side for all known plaintexts and compute the pair-wise GCD between them. The smallest result will likely be the modulus. Verify your guess by trying the public key parameters at additional known plaintexts.
Comment: I can find $N$ with high probability as the GCD of the results of the left side of the equation. See [my answer](http://crypto.stackexchange.com/a/27571/23623) for the details on how many known plaintexts are needed.
Comment: @SEJPM Nice! I like the method for finding N.
Comment: so you're saying that, if we only had the ciphertext and somehow computed all possible RSA public keys (assuming size < 2048), then encrypting the plaintext with any one of these keys would always result in the ciphertext?
Answer: I'm quickly assuming your question asks how to retrieve the public (RSA-) key from a set of samples of unencrypted and encrypted messages.
If you're question is about: "How can I get my files back after being infected by CryptoWall?" I suggest you read the hits by the search function on InfoSec.
Please also note that in most use cases RSA isn't used to actually encrypt the messages (like files) but rather encrypt some keys which are subsequently used to encrypt the files symmetrically. This is what CryptoWall does.
Please note further that knowledge of the encryption key for RSA doesn't imply knowledge of the decryption key. So using the below method you'll be able to find the public (encryption= key for textbook RSA, but not the key neccessary for decryption. Note furthermore that retrieving the public key from secure RSA variants (used in practice) is impossible as outlined by Yehuda.

Now to the strategy of finding the public key for textbook RSA given a set of message-ciphertext pairs $\{(m_0,c_0),...,(m_k,c_k)\}$.
First observe that, by definition of RSA, $c_i\equiv m_i^e \pmod N$ holds for the (not) given public key $(e,N)$. We can't easily retrieve $e$, so we have to guess it to proceed. Usually $e=3$ or $e=2^{16}+1=65537$ holds and if not one can apply the below procedure to any guess of $e$. If $e$ is chosen at random the method doesn't work, but in practice $e$ takes the above fixed values.
Next observe that $m_i^e-c_i\equiv 0 \pmod N$, implying $m_i^e-c_i=a_i=r_i\times N$ for some quite random $r_i$. Now we can compute the $a_i$  for all our plaintext-ciphertext pairs. Now note that that all the $a_i$ have the $N$ as factor in common. We can now apply the pair-wise gcd to all pairs of $(a_i,a_j)$ we have and see that $gcd(a_i,a_j)\geq N$ and $gcd(a_i,a_j)=N$ if $gcd(r_i,r_j)=1$. Thus by computing all the GCDs and taking the smallest value we observe, we can find the correct modulus.
We can confirm that we indeed found the correct $(e,N)$ pair by simple computing $c'_i\equiv m_i^e \pmod N$ and confirming that $c'_i=c_i$ holds for all ciphertexts we have.
To get to the below formula, first observe that the probability that two random integers are co-prime is roughly $6/\pi^2$. Now the probability that they aren't co-prime is obviously $1-6/\pi^2$. The probability that all the pairs of $r$s we have aren't co-prime is $(1-6/\pi^2)^{\text{NumberOfPairs}}$. The $\text{NumberOfPairs}$ is the number of pairs we can build from our set of size $k$, meaning we can find $k(k-1)/2=(k^2-k)/2$ pairs of $r$s. Now finally observe that $\Pr[\text{At least one pair is co-prime}]=1-\Pr[\text{no pair is co-prime}]$. And finally bind this back to the above explanation and see that we find the modulus only if we hit at least one co-prime pair of $r$s, yielding the below equation:
$$\Pr[N=\text{modulus}]=1-(1-6/\pi^2)^{(k^2-k)/2}$$
So to achieve a given probability $P$ that we found the modulus (and not anything larger), we should have at least $k\geq5$ plaintext-ciphertext pairs (for probaility $\approx 0.9999$). If we want to be really sure $k\geq12$ should yield $\Pr[N=\text{modulus}]>1-2^{-80}$ (same with $k\geq20$ and $2^{-256}$)
Comment: I really hope that the $r$s are random enough and that the $a$s are large enough to use $6/\pi^2$. FYI, the $a$s should be roughly 16MiB large for $e=65537$ and $\log_2(N)\approx 2048$
Comment: If anyone asks: The run-time *should* be polynomial as wee need a constant amount of guesses for $e$ (assuming $e$ is small or fixed), we need a constant amount (5,12,20) of modular exponentiations per guess, we need a constant amount of gcd computations (10,66,190) on linearly sized data (bitlength grows linearly by $e$). I'm pretty sure it won't be *too* fast but still feasibly fast.


How do viruses or bacteria survive outside the body long enough to spread?

Question: Say I cough on my table, then someone else touches it and picks up something I've got... how is it that these things can live outside the body, how long can they manage it, and how long is generally 'safe' to consider something no longer carrying these germs?
Comment: depends on the species and its constitution... Can you be a little more precise..
Answer: It depends entirely on the environment the virus or bacterium is in and also the size of it.
Virus
With regards to viruses, the most important thing is typically whether or not the virus has an outer membrane or envelope.
Non-enveloped viruses such as rhinoviruses, noroviruses and adenoviruses can in fact survive for long periods outside the host (up to several days) whereas viruses with membranes such as HIV, influenza and the herpes viruses which do well in the host survive for shorter time periods.
Experiments with rhinoviruses and influenza viruses have shown potential survival times ranging from a few minutes to 48 hours or more.  They remain active longer on stainless steel, plastic and similar hard surfaces than on fabric and other soft surfaces.
This is because many enveloped viruses rely on the proteins on the surface of the membrane to attach to the host cell, this envelope is generally sensitive to degradation to sunlight and normal cleaning procedures.
Outbreaks associated with the non-enveloped viruses can continue for many months due to their relative stability in the environment, think of winter vomiting outbreaks, hand foot and mouth in animals as good examples of this phenomenon.
Bacteria
Because bacteria can undergo metabolism, synthesise proteins etc. for themselves, their life span is usually longer. If we split them into gram positive and gram negative its easier to discuss. Gram positive bacteria have a protein coat that prevents drying allowing them to survive longer. An example is the bacteria Staphylococcus aureus, which is responsible for toxic shock syndrome, food poisoning, and wound infections. With its protein coat it can withstand temperature and humidity extremes. The spore may survive for weeks on dry clothing using sloughed skin cells for food. The Bacillus anthracis, the anthrax bacteria, can also form spores and survive tens to hundreds of years. This is in comparison to gram negative which need humidity. An infamous example is Escherichia coli which survives typically only a few hours at best.
Answer: Viruses really take to heart the idea of "quantity, not quality." Like animals and plants, viruses and bacteria are a completely different ball game (even more so than animals and plants).
As you maybe know, you have bacteria floating around you in the air right now. Realistically, a single T4 bacteriophage (a type of virus) has a life cycle of about 20-30 minutes at 37 C°. However, in this time period, it often reproduces in a bacterium and creates tens if not hundreds more phage particles using the bacterium like a machine that was hacked to do its bidding.
The only way to prevent a virus from attacking is through vaccinations and other preemptive measures, as it is so difficult to prevent reproduction.
Bacteria are so different they, for all intents and purposes, cannot be approximated. For a rough approximation, somewhere from hours to weeks.
Answer: Virus particles (virions) are not alive. They are just a Genome Delivery Vehicle. They are essentially like landmines. However like different types of landmines different types of viruses can remain "active" for longer or shorter.
Those depend as explained above on the virion structure but also on Humidity and temperature, the fomite (surface) and the ammount of virions. Some viruses need up to 10k Virons to cause disease. The higher this "Particle to PFU ratio" is the lower the chance they can remain active outside the body for long. So if the Virus in question needs few particles, is not enveloped then this one can in theory live for quite a while outside, Norovirus for example is one of those.


3d Lines effect in Illustrator/photoshop?

Question: does anyone have an idea how these pieces were created? The designers seem to use illustrator in their other work, certainly no 3d software?
Comment: The rabbit is by Yehrin Tong. Google her, she's very good. I'd assume this a digital hand-drawing.
Answer: A masterpiece of manual crafting is already suggested by other users. I believe it. No automatic software can combine the multiple functions of the strokes, namely showing the geometric surface form, creating some outlines (rabbit's face features) and creating the shading.
There are those horizontal strokes and the wanted shape as line art for a start. One can add anchor points and make the needed bends by moving the anchors along the line art paths. The path width tool can be used to control the line widths. Some extra strokes can be needed and something must be cutted out of the way.
The line art is finally hidden or deleted.
Here are some path manipulation examples:

a straight line is added over the quide drawing
anchor points are added in the circles
the anchor points and their handles are moved with the direct selection tool. Note a sharp anchor point on the quide stroke
widths are manipulated with the stroke width tool
more anchor points and width changes are added

In principle this is easy. Creating something nice using these isn't.
The bottle problem is tried in 3D. I have only some simple low cost and free pieces of 3D software. They are radically simplified from premium priced full versions. For example curve lofting and all surface form adjustments are disabled in the version I used. The well formed bottle would benefit lofting (=sweep through different cross-section profiles) or tools to chisel the grooves to the surface. Revolution gives only a simple, perfectly round bottle and that's what I got. As a plus I see the fact that there's no reason to fear lawsuits.
The used program is DesignSpark Mechanical, a free version of SpaceClaim.
See some construction screenshots:

The revolution profile; drawing it was quite same as drawing with the pen in Illustrator
Some preparing lines to create the planes that slice the revolved bottle
The bottle after revolving the profile

4A and 4B. The planar surfaces for slicing the bottle

A sliced half-bottle. Slicing creates lines to the wireframe
Planar rectagular surfaces were drawn (=one is drawn, the rest are copied) to continue the slices in a plane.

The projection can be anything, but I took the default. The view could be spinned freely.
Version 6 was printed as wireframe PDF and taken to Illustrator as 2D. My 3D software has poor control for color and light, so I choosed to color the stuff in Illustrator.

The wireframe PDF opened, hidden lines were turned off before making the PDF
The areas are colored
All strokes removed

The coloring was tricky because all areas were not perfectly closed. I joined some lines and got the job done.
ADD: Free 3D model of the Coke bottle is available here:  https://www.turbosquid.com/3d-models/free-coca-cola-bottle-3d-model/811078
It at least seems to be pro quality in the companion photo. Its usage is limited. By purchasing a paid license one can get a right to use it more freely and without any watermarks.
Free 3D models of the Coke bottle can also be found in SketchUP's 3D Warehouse. Those few I tried were low quality attempts, not much better than my elementary version.
Comment: The coke bottle is a bit less complicated structurally, if I could figure that out I'd be delighted. Yehrin Tong certainly is a master illustrator, I guess it is just amazing craft!
Comment: Actually the coke bottle would be easy to do in 3d the first not somuch
Comment: Cheers for the help!

@user287001 - I appreciate the time you have taken with the diagram etc, thank you!
Comment: @joojaa - The 3d coke bottle - would that have to be done in C4D or a full on 3d application, or would Photoshops 3d capabilities be able to handle it?
Comment: @Simonanseo The bottle is added.
Comment: Consider using pathfinder, but doublecklick on the tool and enable gap detection. Good job.
Answer: Here's an unrefined method utilizing Photoshop's Displace Filter I'd pursue....

The key to all this is knowing which artwork will work best, or creating your own original image to distort. In addition to knowing good settings for line frequency and displacement. Like all art styles, it would take practice and experience to be really proficient at it. And I commend the artist creating your samples. Clearly a lot of (experienced) work there.  This answer is merely a starting point to start practicing from. It's not going to be a simple step process to get you crisp, clean images like your samples.

Start with a basic black and white line art image you want to use in Photoshop...

Then add some Gaussian blur to it to make the edges less defined, and reverse the colors - White will be raised, black will be sunk. The amount of blur will determine how drastic the drop off is between the flat lines and the raised lines.

Save that file as a single layered, flat, greyscale, .psd file. You'll need it in a moment.
Now create another Photoshop document the same dimensions as the art image, with a series of lines... I made mine with Illustrator and then copy/pasted into Photoshop as a smart object layer. In the end, you need a single layer of the lines. You can use a raster layer, a vector layer, a smart object - but it needs to be 1 layer only.

Now, with the lines layer selected, choose Filter > Distort > Displace.
Make certain Tile is checked in the Displacement Map options.

Click OK and find the line art file you saved a moment ago and select it.
The lines layer will be distorted to mimic the shape...

By adjust the amount of blur in the artwork image, you can alter the drop off of the distortion, here's less blur....

This sounds like it takes far longer than it actually does. Most of the time would be in experimenting with proper blur amounts and line frequencies to accommodate the displacement.
If the end goal is crisp, clean, precision... From here, I'd take the image into Illustrator and manually mimic the distortions of the lines, using the image as a guide. You could also try Live Trace in Illustrator, although I don't think I would personally rely on that.
Comment: Thanks so much everyone for such amazing contributions!!!
Answer: Based on her public-facing work, I'd say three main things:
1) There's no guarantee there wasn't 3D modeling used: she clearly does have that skillset and tools.
2) Nonetheless, it's REALLY not likely: she tends towards hugely complex, very carefully crafted pattern and dimension creation in a sheerly-vector manner, and is obviously immensely skilled at hand illustration too. My bet is this was all done manually.
3) That said, I don't think a trip into either photoshop or a separate 3D DCC is necessary for lower-complexity forms: Illustrator has decent revolve & extrude tools for simple shapes. You could create a vector pattern symbol of the colour lines, revolve a bottle-shaped profile, and Map Art onto that 3D form, then explode the result and do point-specific tweaks to get it dialed in, and that would all stay in illustrator's vector tools - no need to trace pixels at all.
I've tested now - this approach works well, but fair warning: Illustrator's "3D effect" tools are slow and processor-heavy.
See attached.


Renaming a custom field name in User profile

Question: We have few custom fields in User profile. All users are set with data for those custom fields. I am trying to rename a custom field name in User Profile (Core DB) which results in that field value becoming empty. Again if we revert back the field name to old name then value is showing back. Please suggest.
Comment: Do you have custom code which references the fields by name? If so, you will need to change the names to the new names you are using
Comment: Yes. We are referencing and I have  updated code to point to new field name. Thanks
Answer: Additional notes for Mark Cassidy's answer that, if you change the name of the user profile field in Sitecore you can migrate these values for the changed name.
So you need something like this:
foreach (var user in UserManager.GetUsers())
{
    var oldvalue = user.Profile.GetCustomProperty("Old Fields Name");
    user.Profile.SetCustomProperty("New Fields Name", oldvalue);
    user.Profile.Save();
}

Be careful because this UserManager.GetUsers() gets all users, and maybe you want to filter by domain for instance. Then you can use the Domain.GetDomain("yourdomain").GetUsers() method.
Answer: User profile fields are not Sitecore.Data.Field. What you define in the custom profile is merely a mapping so that Sitecore can provide a basic UI for the user, such as this.

Behind the scenes, these profile fields are used with the standard ASP.NET ProfileProvider - and this uses the profile name as key. Which means you cannot rename these, and expect to keep their value.
user.Profile.SetCustomProperty("Address", address);
user.Profile.SetCustomProperty("Phone", phone);

Explained here: Sitecore users custom profile properties


How can I turn off the home screen preview of SMS/text messages in my Galaxy Note 2

Question: On an Android device (Galaxy Note 2) with a locked screen whenever an SMS is received it's preview is displayed over the locked screen. This is super inconvenient - anyone who is nearby can see it without even unlocking the screen.Is there a way to disable those previews over a locked screen?
Comment: Messaging Apps like Viber has settings to enable or disable these features. You can check how to setup those settings here http://justcode.me/how-to/how-to-turn-off-viber-message-preview-on-lock-screen/
Answer: i have been annoyed by this as well!!
even after turning off as mentioned above i was still receiving the notification and preview of the msg
my problem turned out to be an add on sms widget for evernote "sms to evernote" that gives you the option to send your sms to evernote.
It is not obvious from the pop up that it is evernote
there are two options in the "sms to evernote" settings
"Enable sms pop up"  when you enable this you get further options to "hide sms in pop up"
The "hide sms in pop up" option does not work you get the preview regardless
it took me a while to work this out and i hope this saves someone else some time :-)
Comment: You might want to format the question to be more on-point, I almost deleted it as a "Me Too!" answer.
Answer: Open the SMS app and fire up the Settings option from the Menu button.
In the Notification Settings sub-section there is a Preview Message option. If checked, that will show a preview of the message in the status bar and on  the lock screen.
Uncheck it, and your problem should be solved.
Answer: Yes, you can do that using Settings->Lock screen settings and changing there widgets.
Answer: You can go to Messaging, go to Settings by pressing the button next to home button, scroll down and disable Preview Messages ... or even better disable notification.


Event Receiver site creation

Question:
I've got this eventreceiver that fires after an item has been added to a list.
The eventreceiver creates a subsite from a template I created myself. The only
problem is, every first time I try to add a listitem (so actually create a subsite), I have to wait +40 secs and the subsite wont be created. But the next +100 times I try to add the subsite after my first attemt, every site has been created succesfully.
In other words, in this situation my customers have to create a "bad" subsite first before they can actually create a working subsite. I'm using SharePoint online. Does anybody know how I can fix this problem.
Regards,
Fabian
Answer: Creating a site is a long running operation and therefore its a bad practice to do it an ItemAdding event which is synchronous by default.  Make it on the ItemAdded Event and then it will be created, but no visual feedback will be given to the user.
Normally for this, we create a custom action on the list item, that custom actions open a simple aspx page with a long running operation and there you can show visual feedback to the user that the site has been created.
<code>using (SPLongOperation lo = new SPLongOperation(Page))
   {
      lo.Begin();
      // Load controls and stuff
      lo.End(????);
   }
</code>
Answer: Doing anything even moderately intensive in sandbox code (like creating a subsite) is asking for trouble, sooner or later.  You may find that creating a fake list item and broken site will become a "deployment step" in this scenario.
If your environment is on 2013, I'd like to suggest an alternate approach:  Create an auto-hosted App with a web service that creates the subsite. Then, instead of an event receiver, put a workflow on that list that calls the web service.

Event Receiver site creation


How-to Un-Join Domain when DC not available on Win 2008 R2 Core Installation Hyper-V

Question: Server was moved and domain contraller not available any more. Is it a way to disjoin Domain on Win 2008 R2 Core Installation Hyper-V?
Answer: Is the server a Domain Controller?  If not, I believe you can just put the server in workgroup mode and delete the computer account from the domain.  Someone correct me if I'm missing something here.
Comment: Yep, switch it to a workgroup (might have to use the force option). Then delete the account from the domain.
Answer: You should of course be aware of the excellent core utilities which makes all this a bit simpler for us command line impaired.
http://blogs.microsoft.co.il/blogs/guyt/archive/2008/03/22/windows-server-core-coreconfigurator-to-the-rescue.aspx
http://www.smart-x.com/?CategoryID=198&ArticleID=170&sng=1
Answer: I was dealing with this exact issue when trying to disconnect a copied VM from another network.  The DC from the previous environment wasn't available in the new location and my VM was also a Win2008R2 Core installation.  Under the same conditions, the GUI domain/workgroup tools in Computer Properties would have disconnected it from the domain.
I was using the domain GUI tool from CoreConfig and got this error, and also got it from netdom.  Adding in the /force option in netdom was the fix.  The GUI tools from a full installation of Windows apparently take care of this automatically.
netdom remove /d:mydomain mywksta /ud:mydomain\admin /pd:password /force


How can I avoid peeling my hangnails?

Question: I have a tendency of biting skin around my finger nails that looks like it is going to come off. This skin sometimes looks like it wants to peel off, especially after doing manual work. I noticed that when I have a disturbing thought or when I am bored I put my finger between my teeth and cut my skin which then peels off leaving my finger with a wound.
Answer:
If the skin is going to come off, it's definitely going to come off. Let it hold you for some more time. Forcing it to peel off definitely hurts the skin surrounding it. And also, biting our finger skin is unsafe as it may have numerous germs.
Skin near our fingers are stressed when we do a lot of manual work, which partially blocks blood flow. One thing which helps me overcome biting skin near nails is to apply lubricants like oil or lotion.

I am a drummer and I face the situation quite often. Using oil or moisturising creams to keep the skin active is what I follow and it really helps.
Answer: Try maintaining your skin too. Keep a 99 cent nail file on hand that you can use on callouses or rough skin near your cuticle. If you start picking, biting, etc. consciously smooth your skin with the file.
Comment: Using a nail file or emory board really does help. Clip the hang nail as close as you can with fingernail clippers, then do as djechlin suggests and smooth with a file or emory board. Put moisturizing lotion on afterwards to keep it from drying out, since the dried skin is easier to pick at.
Answer: There are foul-tasting materials that can be applied to the nails to remind you to keep your hands from your mouth, or wear gloves.
Even if it's just while you're home alone, wearing of gloves is a reminder that will help you to break the habit. BTW, I had a similar issue, but after a hand injury required bandages for a week, my bad habit was broken.
Answer: Just keep thinking about all of the gross germs that live on your fingers when you start to bite them. Unless you like being sick, you will probably want to stop.

How can I avoid peeling my hangnails?


Was Reuben's repentance accepted? If not, why not?

Question: The midrash (Bereshit Rabba 84:19) indicates that Reuben did teshuva (repentance) for sleeping with his father's concubine Bilhah (Bereshit 35:22). However in both Yaakov's blessing (ibid 49:3-4) and in 1 Divrei HaYamim (5:1) Reuben's sin is discussed as if his act teshuva had not gained him forgiveness.
I would like to know if my assumption that Reuben's sin was not forgiven is correct, and if so why not. If his repentance was in fact accepted why was he still described as being a sinner.
Answer: Rav Hirsch explains that Yaakov first turns to determining which of his sons will become the leader of the family. As such he discusses the character traits that will lead to the malchus (kingship). This means that he is saying that even though Reuven repented of the actual action, the character flaw that led to it still disqualified him from becoming the king.
This flaw was that he was unstable as water. Another translation of Vay'chi 49:4 is

[You have] the restlessness of water; [therefore,] you shall not have superiority,

Rav Hirsch explains:

But as nevertheless he says here: "you are the most precious gem in my
  treasury, are כחי וראשית אוני, but for the leadership of the family
  you are not qualified, for that one must be עז, may not be moved by
  soft flattering winds nor by stormy hurricanes, must have strong inner
  firmness not be unstable like water", from all this it was evident
  that the incident referred to could not have had that importance which
  the harsh blunt words וישכב וגו would seem to imply.

Reuven had a tendency to jump up and act hastily, as we see when he offered to allow his two sons to be killed if he failed to bring back Binyamin. He rushed off, planning to rescue Yosef, without thinking that others (like the Midyanim) might come by and pull Yosef out and sell him. In fact he moved his father's bed from Bilha's tent to Leah's because he was sensitive to the honor of his mother. This is what is regarded as his sin even though it is not the literal meaning of Vayishlach 35:22

And it came to pass when Israel sojourned in that land, that Reuben
  went and lay with Bilhah, his father's concubine, and Israel heard [of
  it], and so, the sons of Jacob were twelve.

As Rashi says:

and lay: Since he (Reuben) disarranged his (Jacob's) bed,
  Scripture considers it as if he had lain with her. Now why did he
  disarrange and profane his bed? [It was] because when Rachel died,
  Jacob took his bed, which had been regularly placed in Rachel's tent
  and not in the other tents, and moved it in to Bilhah's tent. Reuben
  came and protested his mother's humiliation. He said,"If my mother's
  sister was a rival to my mother, should my mother's sister's handmaid
  [now also] be a rival to my mother?" For this reason, he disarranged
  it. — [from Shab. 55b]
and so, the sons of Jacob were twelve: [Scripture] commences with the previous topic (i.e. the birth of Benjamin). When Benjamin was
  born, the marriage bed (i.e. the destined number of sons) was
  completed, and from then on, it was proper that they be counted, and
  [so] it (Scripture) counted them. Our Sages, however, interpreted that
  these words are intended to teach us that all of them (Jacob's sons)
  were equal, and all of them were righteous, for Reuben had not sinned.
  — [from Shab. 55b]

Rav Hirsch emphasizes that this was a character flaw that prevented leadership rather than an actual sin.

To a son who was the כח וראשית אונו of his father and who should be
  יתר שאת ויתר עז any offence which would otherwise be considered quite
  lightly, is taken most seriously. Had he really committed a real sin,
  surely a Jacob would not have designated a Reuben by such a mild and
  gentle epithet as פחז כמים.


Is there an iPhone photo app with exposure compensation?

Question: I'm looking for an iPhone app that features exposure compensation, any suggestions?
Comment: It may or may not even be possible using the basic SDK. I'm pretty sure some apps will post-process the JPGs to change exposure, but it might be worth trying to find out if the iOS SDK actually provides a function to capture a photo without auto-metering or with compensated metering.
Answer: Camera+ claims to let you adjust the exposure (which is what exposure compensation does)!
http://campl.us/
Comment: Yargh, only available in the US Store.
Comment: Is there an Android version?
Answer: Technically the answer is "there isn't one." The SDK does not allow much control over the camera so any apps claiming to do exposure compensation are just "faking it" by post-processing the image.
With the built-in photo app, you can adjust the exposure by pointing at the part of the scene that it should take the exposure from (it also focuses on the same point). This works on the 3GS and above. This trick should work in any app that can take pictures, too.
Comment: Generally tapping on that part of the image works as well.
Answer: Currently, the default iOS Camera app that comes with all iPhones does exposure compensation.  All you do is tap to set focus/metering, and a little sun icon comes up. Dragging up/down lets you increase/decrease exposure.
Comment: I don't see any slider, but tapping to screen will switch to spot metering on that place and sliding up or down anywhere changes exposure.
Comment: @Orbit, I'm on an ancient 5S, and I still see the slider line under the sun icon. :) But I'll edit.
Comment: Great, I made a tiny correction.
Answer: I know this is no quite about EC, but I thought this might be useful...
I don't have an iPhone myself (more of an Android person...), but I have a friend with an iPhone and he has the Pro HDR app. I must say I was quite impressed when I saw it work; you just click two positions on the preview of the image and it takes two photos, one after the other and then aligns and merges them. I wish someone would create such an app for Android :-)
It costs, ($1.99) so I would say that it's probably only worth it if you have a 3GS, because the cameras on the 3G and below are notoriously bad. And the iPhone 4 has HDR built in!
For some examples look here: http://www.flickr.com/groups/prohdr/
Answer: I've used Camera+; Touch Exposure & Focus feature
From site:
Set exposure separately from focus for the ultimate control of your shots… simply touch with a 2nd finger while focusing to adjust exposure until your shot is perfect.
iPhone 4 and 3GS running iOS 4 only
It works as explained, but it's almost impossible to hold the phone, touch two spots on the screen and then touch the shutter icon. It's much more trouble than it's worth.
I think the original Camera+ used the volume buttons as a shutter, and was pulled from the app store for failure to follow Apple guidelines.
Answer: KitCamera seems to be able to do what you're asking for. It's now free, and has an actual exposure compensation slider. Which is a bit odd, as that's not supposed to be possible. Perhaps it's a hack or a kludge; I don't know. Regardless, iOS 8 allows apps to do this natively, so we'll likely be seeing this feature added to many camera apps.
Comment: Fair enough. I've expanded the answer.
Comment: Can you elaborate? I mean obviously you're saying it provides you with exposure compensation, but a brief list of features, whether it's a free app, something more than a link-only answer?
Answer: Camera Awesome
Camera awesome will allow you to change the exposure of a photo before and after you take it. Hey but with iOS 8 coming out soon there are advanced editing features :)
Answer: The iPhone camera doesnt suck, it's more often the operator who has not taken the time to learn how to use it correctly. I've got many images that are as good or better than my D700. They were often times simpler to get and didnt require me to carry 8Lbs of camera around. I did a show where I mixed iPhone 4S and 5S images with DSLR images and challenged anyone in the audience to tell which was which. Nobody could. The whole "the Iphone (or any other smartphone) is a not a real camera" thing is an urban myth.
Comment: this is more a comment than an answer. (You raise good points BTW.) Once you get some upvotes you'll be able to comment. Welcome to photo.stack also, glad to have you around.
Answer: When i use my Procam6 app, if i want to compensate ( change the exposure from what the app wants to set ) i just tap on shutter speed ( or ISO ) and change it the amount of stops i feel is necessary.
Edit: i just looked at the Procam6 -  tutorial and it states:
"Note: While in auto mode, the exposure (AE) value can be set between -8 and 8+. The camera will automatically and continuously adjusts ISO and shutter speed to achieve the selected exposure value. The default value is 0, which means that no changed were made to ISO or shutter speed."


Why Are Mining Passwords 'x'

Question: In any of the 'get started mining' type sites, I see that password is always x. In xmr-stak, it seems to suggest putting in 'mostly empty or x' as a password. Does this really mean I should be using some default one-character password, or am I just misreading?
Comment: Thanks for the answers! Unfortunately I can only pick one as 'the' answer, though I'd probably take all three that have as of yet been written if I could. To support decentralization, I think I'll give it to the answerer with the least rep.
Answer: It's a placeholder, since they're unused (or, at least, I am not aware of any mining software which uses that password), even though they're part of the JSON communication between miner and pool. You can put whatever you like, x or otherwise.
Answer: They're used to login to the pool's UI, usually if it's an email address the pool will also email you alerts regarding the status of the worker.
Answer: The 'x' is just a placeholder. It is up to the pool to decide how to use it. It is just an optional message that could be passed between a miner and a pool. For example, often pools allow miners to use it to assign individual workers names/IDs.

Why Are Mining Passwords 'x'


Does a timing chain need maintenance?

Question: Does a timing chain (as opposed to timing belt) need any specific maintenance? In particular I'm talking about a BMW Z4
Comment: They also cause 3x the amount of damage when they snap.  Flying chains will seriously tear stuff up under the hood!  :-)
Comment: My Skoda Felicia has chain replacement interval of just 60'000km and both times it was changed at specified times it was noticeably stretched and made rattling noises while running.
Comment: as far as I know they require no maintenance, they just last a lot longer.  my understanding is they last 3x longer than timing belts but are ~3x more expensive to replace
Comment: So if an average timing belt is to be changed at 60,000 miles (average) I can expect a chain to snap at 180,000?
Answer: While regular maintenance is not required, it is advisable to regularly check how much the chain has stretched, say every few 100K. If the chain stretches too much, the tensioner may no longer be able to perform its job. There's also the problem of the pins becoming a bit loose in the side plates.
The chain should also get a visual check whenever the opportunity presents itself to ensure there is no evidence of things like side plates starting to become loose. Rollers should be felt to ensure there is no discernible play between roller and pin.
Timing chains don't often break but when they do they generally take chunks of the engine with them, as well as allowing valves to get too friendly with the pistons, on most engines.
Comment: How difficult is it to visually check the timing chain? I know the timing chain is a nightmare to replace on BMWs (being at the back of the engine), so would the engine have to be removed just to check the chain? Thanks
Answer: I'm used to timing chains on American V8's, but they will "stretch" over time (think 200k miles) and sometimes on high mileage engines they could "jump" a tooth if they are too stretched out.
But they do not require any maintenance.
Comment: Checking chain stretch is a maintenance item that really needs to be done on them.
Answer: Regular maintenance is not needed. However, a "rattling" noise that changes with engine RPM may indicate a problem with the chain or timing gears. Usually this isn't an issue until higher mileage (150k +).
Next time you go by your dealership, ask them if they've had any problems in particular with your year model. If you hear of instances of chains commonly being replaced at X miles because of some problem (and you trust your source), then you may want to take preemptive action.
Answer: BMW timing chains are engineered for the life of the engine and never need maintenance or replaced.  To prove that point BMW has always performed several long distance tests on its new engines before they are put on the market.  Back in the 90s they took a e34 (5 series) and ran it over 2 million miles, just performing the standard maintenance.  When they took apart that engine everything measured to spec.
Enjoy your Bimmer and just make sure to get the regular maintenance performed but no need to worry about the timing chain. Now if you're a e30 guy like myself, you're stuck with the single worst decision (sorry second worst, after hiring Chris Bangle) Bimmer engineers made and that was to go with a 'quieter' rubber band timing belt.  Argghh!!
Chris
Comment: The problem with those high mileage tests is that they're not indicative of normal use.  Running an engine continuously for a long period of time is *much* easier on all the parts than the typical start/drive a few miles/stop cycles that the majority of cars will see.
Comment: As with everything in a car: everything can fail :) and usually not close to the manual replacement time. Just follow symptoms. if something is giving you a clue that the timing chain is extended or broken, go after it (after checking other easier things that may also cause the same symptom, of course)
Answer: Long chains will get loose sooner, hard shifting will knock it around and shorten its life, infrequent oil changes will interfere with lubrication as the carbon builds up on the chain. Most engines either have an automatic tensioner, or a good guide to help it from slapping. Belts are good, but some are very hard to change. Too bad manufacturers don't try to make the belt easier to change as it is needed to be replaced at some significant expense.
Answer: Just had a timing chain snap on my 1 series 88k on the clock on a 2014 model. 3days out of warranty but bmw did give me a new engine but I to pay for the labour.
Everything wears.
Comment: I'm not sure this answers the question.  Could you be more specific about the *maintenance* you perfromed on the timing chain, if any?

Does a timing chain need maintenance?