When does the main client relay its knowledge of TXs in INV message?

Question: The inv message is used to relay one's knowledge of blocks and txs to other clients in the Network. When a new Client connects to the Network, it first receives information about all the blocks in form of an inv message, as a response to getblocks messages. As there is no gettx message, I presume the information about transactions is  relayed in the last inv response to getblocks. Is that indeed the way the Standard Client operates, or does it just relay the tx messages only when they arrive, making newly connected Clients wait to catch up with the information about the txs?
Answer: ThreadMessageHandler2() calls SendMessages() every 100 seconds, which causes inv messages to be sent to the client's peers.
One peer is picked at random to receive inv messages which reference all the pending transactions that we know about and it doesn't, including the ones we created ourselves.  The rest of the peers receive a inv messages which only reference around 25% of the pending transactions that we know about and they don't, not including any of the ones we created.
A comment in the code explains that this "trickling" of transaction inventory is to protect privacy.
Edit: I just noticed this thread which also describes the process of advertising transactions.  Luckily it agrees with my description here.
Comment: Sleep(100) means 100 milliseconds, not seconds.
Answer: The process of announcing and sending data is the same for both transactions and blocks: inv announces the hash of an object, getdata is used to request the object itself, and tx or block are used to submit them.
getblocks is a step before this process: it requests the announcements of recent blocks via inv.


Reasons for attaining preta janma and how to get relieved

Question: What are the reasons for attaining for preta janma [various are there] and how to get relieved from that? viz  what are the prayaschittas to be done for that?
Comment: @ChinmaySarupria Bhagwad Gita Chapter 18 verse 66 http://www.bhagavad-gita.org/Gita/verse-18-62.html. Where Shriman Narayana himself told the simplest path to moksha and removing sins viz Exclusive- Sharnagati.
Comment: Sharnagati is the best prayaschitta for any papa karmas in current life and past lives of a jeevatman, you will attain moksha directly instead of rebirth.
Comment: @yogi--The later part you have answered but the former part? That answer also needs some refineness.
Comment: @ChinmaySarupria I disagree, and how is Atmajnana related to Sharnagati. Sharnagati is exclusive surrender to Shriman Narayana.
Answer:
Attaining the preda Janma--
  People who try to take the possession over others property (wealth, money, land, houses, jewellery) exercising unacceptable acts such as robbing, surcharging with interests etc., would be punished with this punishment by god of death Yamraj's retainers and cast them into the Naraka (hell) known as Tamisram.
  To get relieved--
  Narayana started explain to Garuda how to get relieved of this preda janma .When a person is alive he has to do Viruksha sarkam---[விரு÷ஷாற் சர்க்கம்] by his own hands. No karma can prevent this. On the eleventh day of death if it was done he will go to his ancestors place and will attain mukthi.This karma to be done by son, wife, grand son and daughter.
  Source--Garuda puranam--PUNISHMENT 1: Tamisram (Heavy Flogging)
Answer: As per Bhagavad Gita, when the mode of Tamas (ignorance) is predominant, one tends towards bhuta-preta, & hence would eventually be born or exist as bhuta-preta:

यजन्ते सात्त्विका देवान्यक्षरक्षांसि राजसाः। प्रेतान्भूतगणांश्चान्ये यजन्ते तामसा जनाः
BG 17.4 - Those with sattva, worship the gods; those having rajas, worship the demons and ogres; Other people possessed of tamas, worship ghosts and the spirits
यान्ति देवव्रता देवान् पितृ़न्यान्ति पितृव्रताः। भूतानि यान्ति भूतेज्या यान्ति मद्याजिनोऽपि माम्
BG 9.25 - Those go to divine, who worship divine; Those go to ancestors (normal pitru-s or demons), who worship ancestor; Those go to ghosts, who worship ghosts; Those come to "Me", who worship "Me"

Worship doesn't necessarily mean -- hand folded, eyes closed, head down. One may worship by remembering or being in that aura. For example, if one keeps thinking about past (bhuta kAla), then one is said to be worshiping of bhuta.
Following are the ways towards bhuta-preta:

BG 18.28 - The agent who is unsteady, naive, unbending, deceitful, wicked, lazy, morose and procrastinating is said to be possessed of tamas (ignorance).

Once the mode of sattva becomes predominant, the consciousness lifts up from the lower planes and move towards higher planes [towards self realisation].

BG 14.18 - Those with sattva(goodness) go higher [regions]; those with rajas(passion) remain in the middle [regions]; those with tamas(ignorance), who conform to the lowest actions, go down [regions].

There is no timeline for how long one remains in any loka(region). Until one is attached to certain mode among 3, one remains in that or intermediate region.
Gita chapter 14 and several verses in chapter 18 are dedicated to explaining sattva [rajas, tamas] qualities.


What's the real difference between cheap and expensive helmets?

Question: Is there any real difference between the cheap and expensive cycling helmets? Is it really worth buying a helmet at say 3 or 4 times the price of a cheap helmet? Will that helmet really give you 3 or 4 times more protection?
Comment: A lot of people wonder this and there are a lot of helmet choices out there.  The extra expense for ventilation often does not occur to new riders or riders who rarely travel great distances.  I am glad you brought up this question.
Comment: One has to strike a balance between affordability and safety features. The fact remains that helmets aren't designed to last and that, after a serious crash, ALL helmets should go into the garbage.
Answer: No, usually expensive helmets are lighter and more comfortable because have more ventilation.
So, if you plan to ride for long hours it's better to buy the more expensive helmet that you can afford, otherwise - for short rides - a cheap helmet will do the job.
Comment: The same standard of safety achieved by a helmet with more holes in it is a real accomplishment on the part of helmet manufacturers.  Any dummy could probably stuff foam into a hemispherical mold, put a strap on it, and call it a helmet.  A good quality helmet is one that you forget you're wearing.
Comment: And cheap ones, as with much cheap attire, will degrade, the buckles will likely fall apart, the covering will tarnish. And we haven't even hinted on low prices due to sweat shops ...
Comment: Helmets are also a lot like clothing, in that what's comfortable for one person often isn't for another. That aside, yeah, the cheap helmets are usually horribly uncomfortable.
Comment: I think this answer is no longer true. Today there are more expensive helmets with systems like MIPS which are supposed to reduce brain injuries in case of a crash.
Answer: The Bicycle Helmet Safety Institute did a impact test of two sets of helmets. One of them cheap (US$20.00) the other expensive (US$200.00). The results are clear: there's no difference. Buy from a reputable brand.
Just check:

If it has the U.S. CONSUMER PRODUCT SAFETY COMMISSION (CPSC) label
If it is confortable in your head (you'll use it more)

BTW, they give nice and reasonable tips:

"Beware of gimmicks. You want a smoothly rounded outer shell, with no
  sharp ribs or snag points. Excessive vents mean less foam contacting
  your head, which could concentrate force on one point. "Aero" helmets
  are not noticeably faster, and in a crash the "tail" could snag or
  knock the helmet aside. Skinny straps are less comfortable. Dark
  helmets are hard for motorists to see. Rigid visors can snag or
  shatter in a fall. Helmet standards do not address these
  problems--it's up to you!"

Their site is really informative. It's worth to spend half an hour browsing it.
Comment: From a safety standpoint there's no difference, but that's not the only factor to judge a helmet on. How did they compare regarding lightness, bulkiness, comfort and ventilation?
Comment: I don't know if its safe to conclude that theres no difference just based on this test (given the few number of helmets tested and lack of curbstone anvil) - sure, they all meet the minimum requirements which are set for helmets, but not everything that passes is the same (for example, in car crash tests, there are a lot of 5 star cars, but some of them will leave you better off than others after crashing if you watch the test videos!).
Comment: The debate over rigid visors goes on and on for kayaking helmets as well.  The counter argument is that the protrusion may protect your glasses (therefore eyes from bits of glasses) and nose in a face plant situation.
Comment: @neves The tips are the best.
Answer: There is actually some misinformation here. It is true that both cheap and expensive helmets must conform with CE-certifications and EU-regulations etc. but the Swedish insurance company Folksam did a more comprehensive test of bicycle helmets. While the best helmet was a relatively cheap one (if you don't consider the airbag helmet), there was a large difference between the amount of protection they each offered.
Here is a link to the test, but unfortunately it is in Swedish. Google translate was not to keen to parse the link either.
Comment: The reason for these differences is that the CE test is not so much more than dropping a melon in a helmet on the ground from 1m height, which is not too realistic compared to real bicycle crashes.
Comment: Agreeing - greater cost does not necessarily mean greater protection but some helmets are better protection than others. The Virginia Tech study is helpful https://helmet.beam.vt.edu/bicycle-helmet-ratings.html
Answer: Trust.
Of course the manufacturers trade on that, but would you trust a helmet that cost a meagre amount?
The more expensive helmets are generally sculpted and designed to have more ventilation, be lighter, be more adjustable, be more comfortable, but ultimately, do you trust them to do the job.
I wear a helmet because when I race I have to and when I commute I'm under personal pressure to wear one. (To be fair I did recently have a crash and my forehead would have looked worse had I not been wearing one - it at least protected me from a longer cut.)
Personally I spent more money because I wanted light and comfortable, but I also figure that something that costs the same as a big lunch cannot have been designed, tested and built properly.
Comment: Personally, yes, I'd trust a helmet that cost a meagre amount; they're all tested against the same standard (CPSC in the US).
Comment: @freiheit - yes, for the first few time you wear it; but after sustained use, for hours a day, days a week, weeks a year? The old cliché "you get what you pay for" isn't always true, but more often than not. If you're going to wear a helmet (see elsewhere for values of 'if') it just doesn't seem right to me to just spend a minimum amount without thinking about why it's so cheap.
Comment: Adjustability is a big point here. If it isn't adjustable, it won't sit properly on your head, and won't protect you as well.
Comment: @kibbee - A fully adjustable helmet will fit more people properly - true. If you are lucky enough that a less adjustable helment fits well, then theres no benefit spending more money on a more adjustable one.
Answer: From the same manufacturer (or similar reputable) the safety is the same.
This years model costs more, mostly to make up for selling last years model at half price!
The top end ranges do have better ventilation, more comfortable or more adjustable padding and straps and have a logo on the box that says they were endorsed by this years Tour de France winner (unless they have just been caught taking drugs)
Personally I buy last year's model from a reputable maker when the LBS has them on sale.
Since helmets need to be replaced every few years (the plastic degrades) I don't worry about how long a better quality helmet will last. For me the padding and straps become horribly degraded from sweat long before the impact foam chemically degrades.
I also buy two helmets for summer use and alternate them so they at least have a chance to dry out. Older ones get relegated to winter use with the padding removed when I wear a hat.
Comment: A study was done (Can't find reference now, but I know we have answers on this site referring to it)  tested used  old helmet up to 30 years old. It that showed helmets with no visible signs of damage pass the safety standards they were made- age has no impact.
Answer: As long as it meets EU/US minimums, price does not make much of a difference safety-wise; a cheap helmet will do a fine job of protecting you:
https://helmets.org/testbycost.htm
More money gives better ventilation, aerodynamics and comfort but you should question whether a shaped bit of plastic foam can justify a £200 price-tag or if you're just paying for the brand.
Comment: As I understand it, the Australian standards are the toughest, so perhaps one should pay more attention to those.


virtual machine virtualization

Question: If I have a 4 GB machine, I cannot have more than 4 VMs if each one requires 1 GB. True or false? Explain either answer
Answer: False: some VM solutions support memory overcommit(ment). Whether or not it's a good idea is another matter. (Also depends on how strongly you mean "requires".)
Comment: The virtual machine can use the hosts Virtual memory as well.
Comment: And probably will, if the host starts paging any of it to disk. If the memory is overcommitted, that's pretty likely.
Answer: There's an interesting article on Memory Overcommitment and Virtualization at http://blog.gridcentriclabs.com/2010/08/virtualization-and-over-subscription.html if you're interested in the theory behind it
Answer: It also depends on the VM system you use.
For example, VMWare ESX / ESXi will happily do over committment. Xenserver makes no such claim (last I checked).
If you over commit on an ESX / ESXi box, its always better to load up several copies of the same OS, this allows better page merging. You wont get nearly such an ability to over commit if your guest operation systems are Windows, Linux and Solaris. If they are all windows (or linux, or solaris) then on those boxes, over-committing by 20% or more is unlikely to do much harm.
I'm not sure if WMWare Workstation or Player will do it. Certainly when I'm using VMware Player or workstation professionally, I find that trying to over commit will let the VMs run but the performance is horrible - mostly because of the host system paging. It's so bad I don't ever try any more.
So if using a host OS and a desktop virtualisation product, my inclination is to advise lots of RAM and don't try to over commit.
Answer: Actually, you need to make sure you have left enough memory for the host operating system too. Starting too many VMs can use all (or almost all) of the host's memory, which will lead to astonishingly poor performance. I once managed to leave only 256MB RAM for the host OS on my system, and it took almost half an hour to get one of the VMs to shut down again!

virtual machine virtualization


Taxation on split lottery winnings?

Question: If you and another person (or group of people) went in a pool to buy a bunch of lottery tickets, and win, how does taxation work for people who split lottery winnings? Does one person claim the winnings and then "gift" the amounts to the others, or can the winnings be split before taxation and then each individual will just pay their own taxes?
Comment: It's my understand that Lotteries don't recognize multiple owners on the same ticket; so one owner claims the winnings and distributes.
Comment: California does recognize multiple winners on a single winning ticket.
Comment: @quid - I believe most (if not all) government run lotteries in the US honor form 5754 and will split winnings.
Comment: It looks like I stand corrected!
Answer: When you win a lottery or have other gambling winnings (over the threshold), you will receive a W-2G form from the payer. You could submit IRS form 5754 to the payer to inform them to split the winnings and issue separate W-2G forms accordingly.
Note that certain payers do not honor the form and will only distribute a single W-2G form. (The World Series of Poker is an example.)
Comment: WSOP is a different animal than a lottery though. Even if players have backers or percentages in each other, it is still considered the skill of a single entrant that determines the winner. Some of the backing contracts would make a shark blush.

Taxation on split lottery winnings?


Where does the phrase "holy crap on a cracker" come from?

Question: Where does the phrase "holy crap on a cracker" come from?
Comment: Sounds awfully like a sanitized version of "shit on a shingle"...
Comment: @J. M.: Now you've made me want some creamed chipped beef on toast.
Comment: http://www.hrwiki.org/wiki/Crap.
Comment: LOL, never even heard it, but that's funny.
Answer: The only result in Google Books is 2006's Brothers and Sons: An Epic Comedy Adventure by Dana Myrick:

"Holy crap on a cracker! That paint job would cost three or four
  thousand dollars in the city," exclaimed John loudly. When John saw
  the expression on James's face, he knew he had said too much. "But, of
  course, they rip people off in the city, and you're not like that, are
  you Gator?" said John.

In Google Groups there's an older result from Jul 13, 2001 in by John in rec.music.phish:

Holy crap on a cracker!! I wish I could go!

There's a dozen "crap on a cracker" results, the oldest is apparently from 1992's Usher's Passing by Robert R. McCammon but there's no preview to confirm. The next is 1996's The Basement by Bari Wood:

"I'd say it was crap on a cracker, Reed. But what did happen to those bees?"

The oldest "Holy * on a cracker" from Google Groups is "Holy hell on a cracker!" from Oct 12 2000 in alt.roundtable.
The related "Jesus Christ on a cracker" can be found in 1993's Save me, Joe Louis by
Madison Smartt Bell:

"Jesus Christ on a cracker," Macrae said. "You about killed me there."

Finally, as a bonus, here's what holy crap on a cracker looks like.
Answer: Probably not the answer you're looking for but possibly still relevant/interesting.
If we can believe Wiktionary, it says:

Emphatic form of holy crap.

Going with that...

Using holy as an expletive was answered here.
The word crap according to dictionary.com:

Sense of "rubbish, nonsense" also first recorded 1898

And finally, cracker is quite an old English word (1400s?).

So I'd suspect sometime in the early 1900s, as crap started to pick up momentum as the new shi*, one or more creative souls shouted it in excitement and it thereafter spread. ;)
Answer: This is pure speculation, but I would guess it came from the expression "Christ on a cracker!", which I've heard many times in my life. This could refer symbolically to Christian communion, where the wafer is said to literally become "the body of Christ".
Answer: Instinctively, it makes me think of something horrible being served or given in an otherwise palatable package. Perhaps something that should have been good (the cracker) is then totally spoiled by something unforeseen or unwanted (the holy crap).
Answer: "Crap on a cracker" is a name for the dish "chipped beef on toast", which was commonly served to people in the armed services, and much disliked. Also called "shit on a shingle".
Comment: Please turn off your cruise control for cool. And a reference or two would be nice. Thanks.
Comment: Yes, "chipped beef on toast" was referred to as "shit on a shingle", "stew on a shingle" or "same old stuff" in the armed services, see http://tvtropes.org/pmwiki/pmwiki.php/Main/MessOnAPlate and http://en.wiktionary.org/wiki/shit_on_a_shingle and the book, `Band of Brothers: E Company, 506th Regiment, 101st Airborne from Normandy...`. I can't find a link between "Crap on a cracker" and any of those expressions though. That is the specific question, about the crap, so citation please?
Answer: At a guess, it was probably 'Crap on a Crutch' until someone (in media) decided that wasn't PC enough, and it spread from there.
Comment: No offense, but this isn't a very good answer. A random guess that it might have been some other phrase? People make phrases like this all the time. What evidence is there that this phrase is derived from "Crap on a crutch"?
Comment: I've never heard anyone say that. I can't find any citations for it. Do you have any evidence?
Comment: Because "Crap on a crutch" is older?


How do I backup system properly?

Question: How do I backup my system so that if I do backup today, tomorrow when I recover it it's totally the same as yesterday?
I mostly care bout system itself, programs and documents are not that important but still would be nice to keep programs+settings for them.
I need it in case I do something dumb: purge needed package, mess up linux-headers, repository, tweak registry and fail and so on.
Examples:

messed up with XConf and it's not working.
used gconf-editor, did some changes and forgot where I did them, gconf-editor doesn't have undo or "don't save" feature, so I am wondering what the hell did I change?
and so on.
and so on, one more thousand stupid mistakes of a guy who is noob at Ubuntu but likes it and wants to become pro :)
Answer: Well, the best way in the sense that you will copy everything, is to make a bit a bit image of your disk. This has the big disadvantage that, even if you zip it, it will take a lot of space.
Better than explaining this myself, check how to do it using "dd" in this link. http://www.backuphowto.info/linux-backup-hard-disk-clone-dd

How do I backup system properly?


How to improve question to avoid downvotes

Question: I have asked a question here and it was down voted without any comment. I have no idea how to improve it. I feel there is no need for any images (also the data is private). If somebody could point me in the right direction I would be grateful.
Comment: Your question asks why you get different results for different queries but doesn't include the actual queries or example data.
Comment: You don't need to use the real, private data. Instead, set up an example set of data that shows the same issue without compromising real world data. While you're setting up the example, you may even find the answer yourself. If you don't, this at least allows other users to reproduce your scenario. Of course, you need to add the actual queries (that fit the example data) as well.
Comment: OP got an hour, and did not respond with any useful information.  That, and failing to double-check the date ranges to be sure that they were equivalent, got a downvote, and I don't feel even slightly guilty about it.
Comment: OK, I looked at the question.   It has none of the important details that would assist debugging, eg. the two outputs and the set that is common and not common.  Also, the ranges overlap by one day.  I have to down and close vote:(
Comment: foo your data. give us SOME sort of context.. also, be careful linking a question that has been deemed as 'bad' by other users. You're almost opening yourself up to downvotes. Just a heads up.
Comment: @JasonVanBenschoten I was going to tell him that too... and then I was hoping that someone coming here for support would be given the benefit of assistance before suffering the wrath of downvotes.
Comment: @JasonVanBenschoten unfortunately, looking at the -6 votes and the closed mark of death on it, I see that was too much to ask for. Anton, if you edit your question to address what we have brought up, it will go back to the Reopen queue and you will be able to get some help.
Comment: @martinjames No, I guess you shouldn't. It's just a shame he brought down the meta effect on his head unwittingly.
Answer: You don't need to post the actual data, just a representative sample. For example, if you're using Social Security Numbers as an ID, you don't need to post all 20,000 of them, just post two rows with numbers like 111-11-1111 and 222-22-2222. And you also only really need to show examples of relevant fields you are working with. We don't need everything.
Also, you really need to post the query. No one can help you debug something you haven't given them.


People picker does not find users in other domain with two-way trusted connection

Question: Our customer has two domains with two-way trusted connection between them. On one of them they have a SharePoint farm. The problem is people pickers only find users that exist in the domain which has SharePoint installed. According to some msdn articles it should work without any additional configurations. Isn't it?
Comment: This question was answered a year later here: https://sharepoint.stackexchange.com/questions/174389/sharepoint-2013-multiple-domains-in-people-picker/174419
Answer: Had the same issue and logged a call with MS.
They said there is no documentation on the setup and configuration for this.
In the end we Recreated our Farm so that it was in the same domain.
Some helpful links that might help you:
Configure People Picker in SharePoint 2013
SharePoint 2013: "Sorry, we're having trouble reaching the server. "


Why did English borrow more from Latin and Greek than, e.g., German did, in scientific and philosophical subjects?

Question: Is there any known reason why the scholars of the time didn't think it easier to use calques, as for instance the Germans did for the names of some of the basic chemical elements?
Comment: I suspect that there is no better answer than "because that was their custom", or perhaps "that best matched their belief about their language". It's basically a question of fashion, at the time.
Comment: English also borrowed more from Latin than Dutch did. The reason is probably that English already contained many more Latinate words than did German or Dutch, from the Norman conquest onwards: the French invaders are why English also has many more Latinate words in non-scientific areas, such as *probably, contained, conquest, scientific, area* etc. etc.
Answer: If you read German authors down to the end of the 18th century you will see that they used lots of Latin words (and in the 18th century lots of French borrowings as well). But in the 19th century there was a conscious effort to replace foreign words by German equivalents.
Comment: Welcome to the site and thanks for your answer! We try to encourage people to back up their answers with references, do you think you could do that?
Answer: After the French language became powerful during the Norman era, English lost its position in writing though people still spoke it. However, by the end of the 14th century, the French language had began to lose its power affected by the events like losing the war against France(=other French nobles) and Black Death. At the same time, English had started to be written by people again(e.g. Chaucer). After that, people including the rulers wanted English to be more powerful as a language, which led to borrowing many words from Latin that was the lingua franca (in writing) at the time. This coincided with The Renaissance which brought about new ways of thinking (philosophy), science and the revival of the classics. Latin (and some Greek as well) was the language used in this cultral expansion. And this was the time English borrowed Latin words the most.
So, in conclusion, the answer is that English was more motivated to borrow Latin words than other languages. English at the time tried to gain power by borrowing words from powerful languages.

Wermser, Richard. Statistische Studien zur Entwicklung des englischen Wortschatzes. Bern: Francke Verlag, 1976
Gelderen, Elly van. A History of the English Language. Amsterdam, John Benjamins, 2006. 178.

edit:sources added


Identify Volunteers in contact summary

Question: I am testing the CiviVolunteer extension and was wondering if there is anyway to identify that a contact signed up to volunteer based on their profile? I assigned a few volunteers to an event, but I do not see that they signed up anywhere on their profile. I don't even see the event show up on their event tab. Let me know if I am missing anything or if this is a future enhancement. Thank you!
Comment: Which version of CiviVolunteer?
Answer: For now in the contact's profile click on the activities tab and filter out the activity type = volunteer. Status available means the contact has not been assigned to a specific need. Status scheduled means they have been assigned to a specific need.
Comment: Yes, that's right. There is no volunteer tab on the contact summary at this time. Volunteer activities are *not* event registrations, but as stated above are recorded as Activities.
Answer: Under 'CiviVolunteer' -> 'Manage Volunteers' (or similar). I couldn't confirm as none of CiviVolunteer's menus are working on the demo site. I agree a 'volunteer' tab on the contact screen would be great (I thought there was one? It wouldn't be hard to make - drop an email to firstname.lastname@example.com to find out more).
Comment: I'm not sure there is an firstname.lastname@example.com. Please make feature requests or report bugs in the CiviVolunteer project in CiviCRM's issue tracking system (https://issues.civicrm.org).

Identify Volunteers in contact summary


What happens if I have a domain registered with 1 company and the hosting with another and the registrar has server issues?

Question: If I have a domain registered through a company like 1&1 but I want to host my files with Hostgator.  I know I point the DNS entries to the Hostgator information, but my question is, if 1&1 has a server issue, will my domains then be down?
Answer: Once the domain is pointed you should be fine.  The DNS servers handle the requests for your site, not the registrar.
Now, the registrar is hacked and starts repointing the DNS for all registered domains somewhere else, all bets are off.  But this can happen at the DNS level too.


automatically agree to license agreement when using "apt-get install sun-java6-jre"

Question: i am creating a slient setup script on an ubuntu machine that also installs additional packages. one problem i am having is that the sun java package needs a manual confirmation of the license agreement. is there a chance that i can automate the installation so, that the process does not wait until i manually confirm the dialog?
Answer: I believe the package asks about the license using Debconf.  You can change what frontend debconf uses to ask you questions, or even set it to have no frontend, for unattended installs.  Here's a quick article about it:
http://www.debianadmin.com/debconf-debian-configuration-management-system.html
Answer: I automate most program installations on Unix and Unix-like systems using Expect scripts. Expect is targeted at interacting with other programs via scripts and these are very easy to write.
example:
<code>#!/usr/bin/expect -f
sudo apt-get install sun-java6-jre
expect "Password:"
sleep 1
send -- "mypassword\r"
expect "[y/n]"
sleep 1
send -- "yes\r"
</code>
Comment: Improvement edit war! haha! Beat you to it by 2 mins though =D
Answer: Switching front end only suppresses the question - it still needs to be told. This blog post covers it nicely.
Answer: When using a shell script, try using send and expect. Make sure you have them installed. Also check out http://www.manpagez.com/man/1/expect/.
<code>#! /usr/bin/expect -f

apt-get install sun-java6-jre
expect "[y/n]"
sleep 1
send "y\r"
</code>
This script calls the installer and then waits for it to output "[y/n]". When this is outputted, the script continues after 1 sec sleep by sending "y" along with a new line "\r".


Is there a hadd punishment for gheebah/backbiting? Please Answer

Question: Is there a hadd punishment for the crime of Gheebah in Islam, and if there is what is the hadd punishment for Gheebah?Please Answer
Comment: If its slander of someone's character then the Hadd of *Qazf* will apply, otherwise there is no Hadd for it.
Answer: No there are only hadd punishment for what goes against one of the five fundamental goals of shari'a مقاصد الشريعة which are (I'll quote example cases where the punishment may apply for each of them):
The preservation of ...
- Religion / Faith (din الدين) like the case of an apostate that attacks Islam
- Life (nafs النفس) like somebody who kills an innocent
- Lineage / Progeny (nasl النسل) like zina
- Intellect ('aql العقل) like drinking/selling alcohol
- Property / Wealth (mal المال) like stealing
And backbiting doesn't go against these and therefore is not punishable. Also note if there was a hadd punishment for that it would surely have been mentioned in the qur'an. Only details (for example: special cases) may appear in the sunnah.
Now what is the punishment for ghaybah or gheebah الغيبة?
The defintion of backbiting can be found in the sunnah like in the hadith saying:

Do you know what is backbiting? They (the Companions) said: Allah and His Messenger know best. Thereupon he (the Holy Prophet) said: Backbiting implies your talking about your brother in a manner which he does not like. It was said to him: What is your opinion about this that if I actually find (that failing) in my brother which I made a mention of? He said: If (that failing) is actually found (in him) what you assert, you in fact backbited him, and if that is not in him it is a slander. (sahih Muslim)

This makes clear that backbiting is clearly one of the major sins.
And the prophet () has seen in his m'iraj the punishment of backbiters:

The Prophet (ﷺ) said: When I was taken up to heaven I passed by people who had nails of copper and were scratching their faces and their breasts. I said: Who are these people, Gabriel? He replied: They are those who were given to back biting and who aspersed people's honour.
Abu Dawud said: Yahya b. 'Uthman has also transmitted it from Baqiyyah, there is no mention of Anas in it. (sunan abi Dawod)

This is the punishment in the hereafter.
The quran also gave an example of backbiting:

... Would one of you like to eat the flesh of his brother when dead? You would detest it. And fear Allah ; indeed, Allah is Accepting of repentance and Merciful. (49:12)

Now even if I said that there's no hadd punishment for gheebah this doesn't mean one cannot punish backbiters in a shari'a conform way in this life. As in cases you may take a backbiter to a court and a qadi (judge) may speak out a verdict which may be some kind of punishment but that would be based on ta'azir (which depends on the case and the interpretation of the qadi).


Running Linux from pendrive on Windows natively

Question: I am trying to find a program that allows me to run some linux distribution directly from pendrive, in windows, without the need to access the bios or to have administrator permissions.
I need something like colinux or ubuntu portable. But I need a solution that is portable and don't need administrator permissions to execute the linux distribution.
Someone knows a program like this?
Comment: With regards to admin permissions: Is it permitable to require admin permissions to install / configure some software to allow you to run the OS from the flash drive? (And the not having administrator permissions to run it.) Are any other permission changes allowed?
Answer: If you're just looking to have a linux environmental inside of windows try LinuxLiveUSB creator.  You can pick a distro and it'll install a portable VM program onto the flash drive along with the image (you can set persistence too if you like). I don't believe it requires admin privileges to run the VM.
Answer: I'm afraid you have too many constraints in place. If you don't have admin privileges on the Windows installation, you cannot (read "shouldn't be able to") get anything running in Ring0. Unless it is possible to boot the machine from CD/USB/network(!), the only remaining option (apart from hacking Windows) is taking out the hard drive, repartitioning, preparing multi-boot and putting it back.
You could try running it in a virtual machine, but even if it works it will be rather slow without the hardware support for which the VM would require at least some access to Ring0.
That said, you can also try to play it fair and square and ask the administrator whether it would consider allowing you to run some linux on the machine somehow. Given that he/she seems to be at least a bit knowledgeable (since you mentioned you don't have access to BIOS) it might be worth a try.


Can you repent for doing shirk?

Question: Can someone repent for shirk? Like repent in this life, and could be forgiven? Or you can't repent for shirk at all, and you are doomed, maybe? Can someone tell me, are you able to repent for shirk or will you be doomed, if you did shirk, maybe?
Answer: Of course you can. Doesn't matter if you were a Muslim or non-Muslim, you can always repent.
What is to become a Muslim? It is accepting the existence and oneness of God and Mohammad(puh) as Allah's messenger to teach us about Allah and his orders. If you truely believe as this, and if you say it loudly (at least to yourself), you will become a Muslim.
What is shirk then? Shirk is putting something else in the place of God. This may be another god, may be a half-god, fire, nature, your mind, a woman, money etc. It doesn't matter if you are a polytheist, an atheist or a monotheist with a god other than Allah (sun for example, there were people who worship sun). How can someone do this? Either by ignorance or by arrogance.
If you are trying to repent, this means you either gain some knowledge to accept Allah as one true god, or you defeated your arrogance. In either case, if you are sincere, why doesn't Allah forgive you? Is there a just one minor reason?
Why Allah created us? To know him, to admire him, to worship him. Now, you want to do that, but he says no. Why? Isn't it what he wants?
Furthermore, if Allah doesn't forgive who repent, then there won't be any Muslim but prophets.
Lets take a look at some verses. These are for non-Muslims:

And if any one of the polytheists seeks your protection, then grant him protection so that he may hear the words of Allah . Then deliver him to his place of safety. That is because they are a people who do not know. (Surat At-Tawbah 9/6)
But if they repent, establish prayer, and give zakah, then they are your brothers in religion; and We detail the verses for a people who know. (Surat At-Tawbah 9/11)

These are clear and obvious. Even if you are in war, if they seek refuge from you, you have to take them away from battle so that maybe they will hear Allah's word and repent.
Now these verses are for non-Muslims who were once Muslims:

How shall Allah guide a people who disbelieved after their belief and had witnessed that the Messenger is true and clear signs had come to them? And Allah does not guide the wrongdoing people.
Those - their recompense will be that upon them is the curse of Allah and the angels and the people, all together,
Abiding eternally therein. The punishment will not be lightened for them, nor will they be reprieved.
Except for those who repent after that and correct themselves. For indeed, Allah is Forgiving and Merciful. (Surat 'Āli `Imrān 3/86-89)

How can a repentance won't be accepted? There are 2 verses about this issue:

Indeed, those who reject the message after their belief and then increase in disbelief - never will their [claimed] repentance be accepted, and they are the ones astray. (Surat 'Āli `Imrān 3/90)
But repentance is not [accepted] of those who [continue to] do evil deeds up until, when death comes to one of them, he says, "Indeed, I have repented now," or of those who die while they are disbelievers. For them We have prepared a painful punishment. (Surat An-Nisā' 4/18)

Here, the 2nd verse is very clear. If you repent while dying, it won't be accepted. What about the other one? There are different commentaries about who are the ones that increase their disbelief:

The People of Scripture. They didn't believe about Mohammad(puh)'s prophecy (kufr 1) and they acted the Prophet and Muslims with disrespect, denying miracles, breaking their oaths, ambushing them etc (kufr 2, 3, 4...)
Jews. They first denied Jesus(puh) and Bible (kufr 1), then they denied Mohammad(puh) and Quran (kufr 2).
Some people converted from Islam (kufr 1), then returned to Mecca and desired and said the failure of Mohammad(puh) (kufr 2).
Some people converted from Islam (kufr 1), then they said they wanted to go back to Islam, but they were hypocrites (kufr 2).
They may go ahead so much in kufr, their hearths will be locked by Allah and so the repentance won't be granted to them.

Allah has set a seal upon their hearts and upon their hearing, and over their vision is a veil. And for them is a great punishment. (Surat Al-Baqarah 2/7)

As you see, unless there is an extreme case (death, insistence with kufr etc), Allah accepts one's repentance if he is sincere about his repentance.
Answer:

In the name of Allah , the Entirely Merciful, the Especially Merciful.

You definably have seen this everywhere because we always start with name of Allah. It says Allah is most merciful.

What is shirk?

If any person included something or somebody with Allah and say "they are same". Like other religious man says "your God and our God", this is shirk and this is the sin which Allah doesn't like.
Some ayah related to Shirk.

But only one who comes to Allah with a sound heart.
Surat Ash-Shu`arā - 89

and another ayah which says how bid sin this is.

And [mention, O Muhammad], when Luqman said to his son while he was instructing him, "O my son, do not associate [anything] with Allah . Indeed, association [with him] is great injustice. Surat Luqmān - 13
And a hadith related to Shirk
I heard Anas say: 'The Messenger of Allah [SAW] said: The major sins are: Associating others with Allah (Shirk), disobeying one's parents, killing a soul (murder) and speaking falsely. Sunan an-Nasa'i 4010 - Book 37, Hadith 45

Would Allah forgive a person who commit this sin?

If somebody accepts Islam, he would be like new baby who is completely sinless.
Those people who are in other religion are doing shirk. They are worshiping other than Allah so when they would accept Islam, they would be like new baby.
Note : It is most important a person repent in his life.
Answer: Allah swt says in many iyat that he forgives the one who repents.  A person can repent from any sin be it shirk, munafiq, kufr, etc.
Allah swt says,
"۞ قُلۡ يَـٰعِبَادِىَ ٱلَّذِينَ أَسۡرَفُواْ عَلَىٰٓ أَنفُسِهِمۡ لَا تَقۡنَطُواْ مِن رَّحۡمَةِ ٱللَّهِ‌ۚ إِنَّ ٱللَّهَ يَغۡفِرُ ٱلذُّنُوبَ جَمِيعًا‌ۚ إِنَّهُ ۥ هُوَ ٱلۡغَفُورُ ٱلرَّحِيمُ ۞"
And the interpretation of the meaning, by Yusef Ali:
"Say, O my Servants who have transgressed against their souls! Despair not of the Mercy of Allah, for Allah forgives all sins: for He is Oft-Forgiving, Most Merciful."
(Az-Zumar 39:53)
http://www.quranexplorer.com
Answer:
 Say to those who have disbelieved
[that] if they cease, what has previously occurred will be forgiven
for them. But if they return [to hostility] - then the precedent of
the former [rebellious] peoples has already taken place.
Al'Anfal 38 (8:38)

قال ابن كثير في تفسيرها: قل للذين كفروا إن ينتهوا عما هم فيه من الكفر
والمشاقة والعناد، ويدخلوا في الإسلام والطاعة والإنابة، يغفر لهم ما قد
سلف، أي من كفرهم وذنوبهم وخطاياهم.. (2407).   Ibn kathir sad in
the tafsir : Say to those who disbelieve (make shirk act ), if they
finish what they are doing of disbelief and stubbornness (the shirk) ,
and enter into Islam and obedience,them ancestor will be forgiven (
forgiven any of their disbelief and sins)

So yes my friend if you repent and you announce Shahada again god will forgive you.

Can you repent for doing shirk?


How should a scene in a screenplay be formatted when switching between a re-telling of a story and the story being told?

Question: I have a scene where a character is recounting their side of a story in a courtroom. The character tells a good chunk of their story, and then we see the experiences he is recounting instead of his testimony itself. How would this be best formatted in a screenplay? The scene would cut back and forth several times between the character telling the story and the actual story unfolding. Is each transition a call for a new location? A whole new scene?
Answer: In essence, for every "flashback", you would  would have to be a new heading, to reorient the reader as to where we are. However, for going to back to "reality", you can simply use BACK TO SCENE, as so:

The strength of this, is that while you're "in" the flashback, you can easily switch locations, and do whatever it is you wish. When you are done, BACK TO SCENE  should always bring back to the courtroom.
Answer: I would highly recommend you watch Akira Kurosawa's Roshomone which does this exactly, multiple times (Much of the film is based on various characters recollecting the same event (the murder of a samurai) from a different perspective.  While a few flashbacks are only given once, these are the established facts which all parties agree on.  The final moments are all in dispute and are told in a reenactment based on what the character is presumed to testify in court.
Comment: You might also want to look at the movie "Go" (https://en.wikipedia.org/wiki/Go_%281999_film%29).  It's the same story told from three points of view.  The transitions are abrupt and apparent, if I remember correctly


What is an FAA Notice? Does it have legal force?

Question: The FAA issues Notices and other non-legislative rules (e.g. Advisory Circulars). These documents are distinct from the laws in Title 14 of the Code of Federal Regulations. What are the differences between them? Do they have legal force?
Comment: I don't know if it helps, but [this page](http://www.faa.gov/regulations_policies/) separates all FAA documents into categories
Comment: Good find. I'm hoping there's a similar page that includes definitions and details of the usage of each type of document.
Answer: As SSumner pointed out, the FAA produces all kinds of paper - some of which is "regulatory" and/or have legal force, and some of which isn't.  I won't go into all of the specific document categories, but I'll talk about a few that most of us will find interesting.

Handbooks and Manuals
The FAA actually publishes full-length books, if you know where to look!
The FAA has written books on flying an airplane,  flying balloons, risk management, buying & owning an airplane, and a whole bunch of other topics which provide broad information that you can use to familiarize yourself with a topic.
Advisory Circulars
Advisory Circulars (ACs) are the FAA's way of explaining their regulations.
They're broken down into sections which generally match up with the FARs they're interpreting.  Some ACs may rival the lengths of handbooks, but they are much more narrowly focused, generally dealing with a single topic and often much easier to understand than the legislation they're interpreting.
Airworthiness Directives
When an unsafe condition is identified in an aircraft or component which requires action the FAA can issue an Airworthiness Directive (AD), requiring that specific actions be taken.
Often the required action is compliance with a manufacturer's Service Bulletin (or compliance with a service bulletin is also an acceptable method of compliance with an AD).
There are also Special Airworthiness Information Bulletins (SAIBs), which are like "Mini-ADs": The FAA is calling operators' and mechanics' attention to something which may not merit an AD. SAIBs are informational - you don't have to comply with them - but it's certainly a good idea to read them and pay attention to the things they're highlighting.
Orders
An "Order" describes procedures used by the FAA. For example, JO 7110.65U describes various aspects of how ATC works.
Procedures described in Orders may be modified by Notices.
Notices
A "Notice" is just an agency's way of saying "Yo! Pay attention! Something's happening!"
Your question seems generally concerned with internal notices which I linked to in the title. These generally modify Orders, like this one.
The FAA can also issue "Public Notices" about changes that affect airmen and the   general public, or pretty much any other topic they'd like.  Public Notices are published on faa.gov as well, but the easiest place to find those is through the FAA Safety Team's SPANS system which is searchable and has a much nicer interface than digging through the FAA site by region.

As for whether the non-legislative documents have legal force the answer is a very well-qualified "maybe".  Some certainly have the force of regulation – Airworthiness Directives being the most obvious – and for our purposes I think that's what you're really concerned with, because the law says you have to comply with the regulations.
Orders and Notices are similarly "regulatory" for the agency: The FAA has to comply with its own orders, so ATC has to be operated the way JO 7110 says it's to be operated.
For stuff like ACs, Handbooks, etc. we discussed this in chat a while back talking about the answer to FAA Order 8900 and the FSMS - the gist of it is that the non-legislative documents the FAA produces are generally interpretations and guidance, but they are "effectively regulatory" in that if you go against them you need to have an excellent reason for doing so, and be prepared to back it up with appropriate justification and evidence if asked.
As a classic example, alterations to aircraft are expected to be performed in accordance with manufacturer's maintenance procedures, or "other methods, techniques, or practices acceptable to the Administrator" which are described in AC 43.13 (43.13-2B deals with light, non-pressurized aircraft and is an interesting read).
A mechanic doesn't have to comply with the guidance in AC 43.13, but if a mechanic were to modify an aircraft without conforming to that guidance they would need to supply supporting documentation as to why their work is acceptable, such as a statement from a Designated Engineering Representative, otherwise the FAA could deem the work "unacceptable" (and from a liability standpoint, the mechanic could wind up in serious trouble should something go wrong with the aircraft as a result of that work).
Comment: This is a very clear summary. Thank you.

Could you add links to the FAA documents these definitions are drawn from? For example, [this question about Airworthiness Directives](http://aviation.stackexchange.com/questions/256/what-is-an-airworthiness-directive?rq=1) cites the [FAA definition](http://www.faa.gov/aircraft/air_cert/continued_operation/ad) of that document type.
Comment: @JeffStreet As far as I'm aware there's no official FAA "what this is" blurb for any of these other than ADs (if you click on the header link for each category it takes you to the top-level page - ADs have the blurb referenced in that answer, and Handbooks have a few empty words that I didn't find particularly descriptive). The interpretive text above is all me -- which of course means I could be completely wrong and talking out my behind. I'm reasonably sure I captured their meaning & intent with the above, but I'm certainly open to corrections if I screwed up :-)


AngularJS bind value into data attribute

Question: Does anyone know how to bind an interpolated value into a data attribute using AngularJS?
<input type="text" data-custom-id="{{ record.id }}" />

Angular doesn't seem to interpolate that value since its apart of the structure of the element. Any ideas how to fix this?
Comment: Can you provide jsfiddle example?
Answer: Looks like there isn't a problem after all. The template is parsed and my controller was downloading the data, but when the template was being parsed data wasn't there yet. And the directive I put needs the data to be there os in the mean time its just picking up empty macro data.
The way that I solved this was with the $watch command:
$scope.$watch('ready', function() {
  if($scope.ready == true) {
    //now the data-id attribute works
  }
});

Then when the controller has loaded all the ajax stuff then you do this:
$scope.ready = true;

Comment: How is the selectOptions relevant to the record.id that you talked about in the question?
Answer: It looks like to me what you are really after is a Promise / Deferred:
// for the purpose of this example let's assume that variables '$q' and 'scope' are
// available in the current lexical scope (they could have been injected or passed in).

function asyncGreet(name) {
  var deferred = $q.defer();

  setTimeout(function() {
    // since this fn executes async in a future turn of the event loop, we need to wrap
    // our code into an $apply call so that the model changes are properly observed.
    scope.$apply(function() {
      if (okToGreet(name)) {
        deferred.resolve('Hello, ' + name + '!');
      } else {
        deferred.reject('Greeting ' + name + ' is not allowed.');
      }
    });
  }, 1000);

  return deferred.promise;
}

var promise = asyncGreet('Robin Hood');
promise.then(function(greeting) {
  alert('Success: ' + greeting);
}, function(reason) {
  alert('Failed: ' + reason);
);

Edit: right, here's a simple example of using a Promise with a Controller and binding:
var app = angular.module('myApp', []);

app.controller('MyCtrl', function($scope, $q) {
    var deferredGreeting = $q.defer();
    $scope.greeting = deferredGreeting.promise;

    /**
     * immediately resolves the greeting promise
     */
    $scope.greet = function() {
        deferredGreeting.resolve('Hello, welcome to the future!');
    };

    /**
     * resolves the greeting promise with a new promise that will be fulfilled in 1 second
     */
    $scope.greetInTheFuture = function() {
        var d = $q.defer();
        deferredGreeting.resolve(d.promise);

        setTimeout(function() {
            $scope.$apply(function() {
                d.resolve('Hi! (delayed)');
            });
        }, 1000);
    };
});

Working JSFiddle: http://jsfiddle.net/dain/QjnML/4/
Basically the idea is that you can bind the promise and it will be fulfilled once the async response resolves it.
Comment: This is great. But, could you please provide an example that better relates to my question? I'm having a tough time understanding it. Thank you :)
Comment: Its basically straight form the docs... it would be nice to give him something that relates to his question.


Memcached can't connect with php

Question: I have centos 5.3 and I just installated memcached 1.4.2.
I can telnet it fine and do stats, etc., but when I try to connect to it over php I get an error that it can't connect.

It was SELinux.
Comment: Could you post some source code or the error?
Answer: It would help if you gave the exact wording/screenshot/log-lines.  I'm gonna bet its that you don't have the php memcache client library installed.  Try this: yum install php-pecl-memcache
Comment: I do have it and i see memcached in my php info.

Memcached can't connect with php


Determine who unfriended me on Facebook

Question: Is there a way to find out who "unfriended" me on Facebook?
Comment: Sounds like a good idea for an applicaiton!
Comment: I constantly recieve spam for applications that supposedly do that.
Comment: Just be weary of the service you choose to track this.  On a similar note there are many that claim they will show you "who is blocking me?" on MSN - they request your credentials to login, then spam your entire address book.
Answer: Intentionally, Facebook prevents sending out this info for privacy purposes.  You are free to keep track of your friends though in some other form, and compare it to the current list to find out who is missing each week.
who.removed.me will do this for you automatically
Comment: Should be combined with http://ifttt.com/ to create a notification service whenever someone removes you.
Comment: @Boris_yo There are many different ways to manage privacy settings on Facebook. That person could still be your friend but may not be using Facebook, or might have said they don't want their updates appearing on your feed, or the algorithm that decides what to show you (it doesn't show all things) decided not to show you that person's updates.
Comment: @Michael Pryor Are you sure that friends who unfriended you disappear from your "Friends List"? I noticed that one person's status updates stopped appearing on my news feed long time ago, but when checked "Friends List" he is still there.
Answer: Sites like who.removed.me will keep track of your friends list and compare it automatically.
Comment: +1 for the site.  I added it to my answer and referenced you.
Answer: One way to keep a log of who has added you as a friend is to enable email notifications. Then create a filter so it doesn't clog your email inbox.
It wouldn't really be practical comparing all these email messages to your friend list, especially if you have hundreds of them, but if you want to check if you were ever friends with someone, you could just search your mailbox.
Answer: If you are comparing friends, somehow you won't be able to tell the difference between a deactivation and a de-friending.
Comment: You could see if there is still a facebook account for that user. If so then it is a defreinding, otherwise it was just a deactivation.
Answer: If using Firefox the Greasemonkey plugin has scripts that will allow you to see this information right on the Facebook dashboard.  The script I use is: Better Facebook
Comment: this app no longer has the unfriend tracker, they had to remove it due to pressure from facebook
Answer: There's an app for that: "Who Unfriended Me?"!
It compares an old list of your friends with a current list of your friends, so that it can show you who unfriended you!
Check http://apps.facebook.com/whounfriendedme/
Answer: The Who.deleted.me app will allow you to see friends who have unfriended you (or have deactivated their accounts). FAQ link here. It can show this list by day, week, month or in graph form.

Also, the Unfriend Notify browser extension for Firefox and Chrome can show a pop-up notification when someone unfriends you on Facebook. It also adds a new tab section for "Lost Friends" in the Friends page, which will list people who have unfriended you.
Answer: Another option for finding out who unfriended you is the FB Purity browser extension. It also has a built in deleted friends notification system, that alerts you if any of your friends remove you from their friends list.
Answer: Try http://truefbfriends.com—It will tell you who are your real Facebook friends and who are fake Facebook friends. It will also give you data like how many likes, comments, mutual friends and chats your friends have done with you. It will also tell who removed you. A perfect website to filter your friends on the basis of interactions.
Comment: If you are affiliated with the product, please disclose that in your answer.
Answer: There is an application on Facebook called Who deleted me ?.
It has 1.9 out of 5 based on 15 reviews. On installing the application you are met with page which will tell you who are your removed contacts. On further inspection, the associated page does seem to have positive reviews.

Determine who unfriended me on Facebook


Naiant X-X omni miniature mics

Question: investigating for a pair of miniature omnis I came across the Naiant X-X.
Did somebody ever had a chance to test or even compare them against the much more expensive Rode Lavalier or DPA 4060?
Answer: You can't expect that the Naiant microphones can perform as well as microphones that cost 10x to 50x more $$$.  You can expect that the Naiant microphones will have somewhat more self-noise, perhaps higher distortion and a frequency response not quite as wide or flat.
Will you actually HEAR these differences in the final mix? It depends on what you are recording and how you are processing it. There are plenty of situations where you won't hear a significant difference.
If you had the budget to buy DPA (or even Rode) then why are you looking at the Naiant?  They all have their place in the marketplace. You can buy a Toyota or you can buy a Lamborghini. The Toyota will get you where you are going just as well as the Lamborghini.
Answer: hi see if you could source a second hand pair mkh-20 sennheisor ..great true ,larger than life can be used outdoor.while the dpas do sound good its a matter of reliability in varied temperatures and moisture levels.if can not afford look for the cheapest omnis that can handle the same conditions.matched pair preferable otherwise match it by listening if you get a choice.
Answer: Your reason to use a mic like this will depend entirely on application and budget. Price of any audio equipment will generally rise with brand exposure and knowledge. However, it is certainly possible that cheaper equipment will be just as useful - but it depends entirely on the application.
for instance, you wouldn't use a lavalier such as this for drama where you need to hide a microphone. It is way too big for hidden use, and so consequently can't be compared to the Rode Lavalier or the DPA dScreet series.
Work out what falls within your budget and then get the best microphone you can for the budget you have available to you that will fit the application you have in mind.

Naiant X-X omni miniature mics


Can any web applications tell if I have Facebook open in a different tab or window?

Question: I have Facebook open in one tab, and I open YouTube in another. YouTube asks me if I want to sign in with my Facebook account. Can YouTube tell if I have Facebook open in a different tab or window?
Comment: Do you mean "can any webapps tell if I am logged into facebook?" evan if facebook is not open in another tab.
Answer: No, individual tabs and windows have no way of knowing which other tabs / windows are open.
Comment: This would be a real privacy concern if this were possible.  Sites could track your presence on other sites without your knowing.
Comment: Sorry to break your 666 rep :P
Comment: No way, is not really correct.  There are a couple of ways that sites can tell what other sites you have been to or currently have open sessions with.  Pages can tell where you came from via referrer links, so if you are coming from Facebook to YouTube they could suggest you login using facebook based on the fact that you came from there.  Also because facebook uses OAuth 2.0, YouTube can use it's OAuth protocol to tell that you are in a facebook OAuth session and suggest that you login using that same session.
Comment: This is "in theory". Things like flash and browser exploits make this less true in reality.
Comment: A site can't directly access your history, but it can tell whether you've previously visited certain specific pages. http://scienceblogs.com/pharyngula/2010/12/another_reason_to_avoid_visiti.php. (It can't, by this method, tell whether you were logged in.)
Answer: However, I do believe that OpenID and OAuth sites can detect if you are signed in to another OpenID or OAuth provider.  This is how they know, and are trying to provide a service letting you know you can use that login on their site.
Answer: Yes, it is possible to tell that you are logged in (or at least used the service). In at least two ways:
1) Explicit connection. If YouTube uses the Facebook API to connect and check whether Facebook knows who you are in that session.
2) Using CSS tricks, where a website can check whether you have specific (well-known) images or files in your browser cache. They cannot tell who you are, but they can figure out which services you use.
The second way is how bookmarking services or OpenID providers can show you your top five services out of several hundreds they support.
Answer: Another way sites could do this is based on a referrer link, so if you come to YouTube from Facebook, YouTube can detect this.
Comment: It is possible to block your browser from transmitting referrer links if you so choose. You can block this in most browsers, the steps for firefox can be found here: http://cafe.elharo.com/privacy/privacy-tip-3-block-referer-headers-in-firefox/

For Chrome, here is an extension: https://chrome.google.com/extensions/detail/dkpkjedlegmelkogpgamcaemgbanohip
Answer: Yes, it is possible, using an invisible 1x1 GIF web bug to access your Facebook cookies.
This was the source of the infamous Facebook Beacon fiasco. As a result of the ensuing lawsuit, Facebook has ceased to do this, and most likely will not try to again.
Answer: It appears that Facebook DOES know you are logged-in on a number of websites - that's probably because you are seeing the new "Like" social widgets ("plugins") that are all over the web.
To the average user, it appears that FB knows you are logged in, because you see which of your friends have "liked" that site or piece of content.  However, technically, the FB social plugins are small iframes that are still hosted on facebook.com:
http://developers.facebook.com/plugins


When do you use "si" and "sia" instead of "li" and "lia"?

Question: I feel like I kind of know this, but sometimes I feel unsure. It's pretty similar to the Swedish sin, sitt. Is there a good rule or a nice, short explanation for when and where to use si, sia instead of li, sxi?
Answer: You asked for short:
Use si/sia when both are true

the pronoun is not part of the subject.
the pronoun refers to the subject of the verb.

Regarding point 1: you'll never see la viro kaj sia edzino estas... because lia edzino is part of the subject.
Regarding point 2: it's important to notice that it's the subject of the verb and not the subject of the sentence, because while they're usually the same, they are not always the same.

Mi vidis lin bati sin (the guy hit himself.)
Comment: Thanks Tomaso Alexander. The link was a very clear explanation. The way I understand it, si looks like it is used to clarify the ambiguity that can happen when using third person pronouns. "Adam likes his house" can refer to two different people (one of whom likes the other's house) and would be "Adamo ŝatas lian domon", or refer to one person (who likes his own house) and would be "Adamo ŝatas sian domon".
Answer: Use si or sia when referring to the already-introduced subject of the sentence:

La virino rigardis la bildon antaŭ si -> "The woman looked at the picture in front of her", the picture is in front of the subject of the sentence ("the woman")
Li eniris sian domon -> "He entered his (own) house", the house belongs to the subject of the sentence ("he")
La infano amas sian patrinon -> "The child loves its (own) mother", the mother belongs to the subject of the sentence ("the child")
Comment: It is also worth noting that *si(a)* can be used **only** when the subject is a third-person pronoun. It cannot be used to replace *mi*, *vi* or *ni*. Those have to be repeated.
Comment: Sometimes *si* appears first, e.g. *Sin trovinte en danĝero, li elingigis sian glavon.*
Answer: The grammar at Lernu regarding pronouns has detailed information about the use of si and sia, available in many languages (the link is to the English version), that is too long to copy here with all the examples. It is worth checking it out.


What is the difference between these two tags?

Question: It is hard for me to understand what the exact difference is between the graduate-admissions and application tags. What are the differences between these two tags?
Comment: Despite what the tag wiki says, some of the [tag:application] questions are about job applications. It seems like a confused tag.
Comment: We already have [tag:faculty-application] and [tag:job-search]. I think it is just a case of cleaning them up.
Comment: @StrongBad It is confusing indeed. May we can have it renamed to *job-applications*. Then we have *job-applications* tags for questions about academic jobs and *graduate-admissions* for questions about applying to masters and PhD levels.
Comment: @StrongBad Good idea.
Answer: I interpret application as being about the package of documents you submit in order to be considered for a job or for admissions. Whereas graduate-admissions is about the admissions process in general. (This is based on my observations of how the tags have been used so far, it doesn't say anything about this in the tag wikis or excerpts.)
For example, I consider the following to be in graduate-admissions but not necessarily application

How does a prospective applicant fail to qualify for RAship, but fit the bill for TAship?
Weaker chance of admit if classmate has already been admitted to graduate program?

whereas the following are explicitly about the application that you submit for consideration

Is there a standard medical fitness certificate format for applicants to European universities?
Is it acceptable to list unpublished papers in a PhD application for computer science?

Along the same lines, in job-search there are some questions that aren't about the actual application, and some that are.
It's a subtle distinction, which is probably why it's not applied very consistently. But I do see this difference in their usage at least some of the time, so I don't believe these tags are redundant.
(I also do find these tags to be reasonably useful in their current state, i.e. even though they are not applied perfectly. So I would use the distinction above to tag new questions, but would not be in favor of re-tagging old questions en masse.)


Where to stand for this winter view in Grindelwald, Switzerland?

Question: I happened upon this r/winterporn post. If you haven't stood at this spot, how did you infer where it was?
Comment: The lighting designer in me is cringing at the mismatch between LPS (the orange), HPS (yellow), metal halide, mercury vapor and various colors of LED lighting.
Comment: @Harper-ReinstateMonica I'm not sure how many of those are fixed and how many are vehicle lights, but the contrast between sodium street lights, halogen car headlights, and LED bike headlights was, for a few years, very useful when cycling.  Now everything is going to white LEDs I have less warning of approaching vehicles at some points. It's all about your use case! Yours of course could be fixed in post (or [ruined](https://imgur.com/a/lMyTwnz) by bad shopping)
Comment: @ChrisH That's easy. The train headlight is very bright, and it can be seen actually following the curvature of the track. *They don't normally do that*.  That makes it a time lapse. Vehicles will leave streaks not spots.
Comment: @Harper-ReinstateMonica I was certain there were some fixed and some moving but it seems to have been downscaled from an image with blown highlights I couldn't say that all the linear lights are vehicles as opposed to rows of lights or reflections from snowbanks
Comment: Any time you have not been in Grindelwald for, say, two months - you miss Grindelwald.  :/
Comment: Winterporn! I love it!
Comment: @Harper-ReinstateMonica it looks christmasy though. Btw OP, this is long exposure. Don't expect it to be this bright irl.
Answer: I've been in Grindelwald early September this year (when there was no snow) but the hill in the background (top two thirds of the picture) is still recognizable as the hill south of the village which leads to Kleine Scheidegg.
After a bit of matching with the 3D view of Google Maps (approximate link) I've identified the Stutzgasse (right red circle) and the railroad (left red circle) which leads up to Kleine Scheidegg:

The next question would be which street on the north hill (the main village) corresponds to the houses in the foreground. I failed to find them at first but it seems to be the Nirggen; the house in the blue circle is quite recognizable:

The photo must have been shot from a slightly higher point, somewhere around here. There's no Google Street View from that road, but this slightly higher road comes close (I've highlighted the railroad and the gray house again):

Views further to the east are blocked by the houses on the Dorfstrasse, and this place (photo shot in the summer) is already too far to the east.
Comment: Your find also proves this shot is a time exposure.  The headlight of the train can be seen curving along the route.
Answer: The original image might possibly be from this blog.
http://qalam-graphics.blog.ir/1396/10/01/Publication69
A similar image is this one

And the hotel is
Hotel Cabana Grindelwald

This photo of Hotel Cabana is courtesy of TripAdvisor
Comment: @Fattie , google is more accurate than a guess. The Parkhotel Schoenegg does not look out on the yard and cabin next to the Hotel Cabana. It is more likely the Jungfrau Lodge or one of the places nearby.
Comment: My method of finding this was less sexy than Glorfindel's. I used image search on Google, Bing and Tineye.
Comment: Yep, that's definitely the same dark brown house (barn?) as the closest one in the picture in the question. Well done, I'm glad we've solved this mystery :)
Comment: Guys, what's with all the google .. tech .. stuff.  The Schoenegg most famously has the best views like that and it's probably taken from like the room upstairs on the left.  (Looking to the left from there.)  Surely there is someone on here who lives in or near Grindelwald!!
Answer: Its hotel cabana for sure

Here is my version
Answer: I believe it's taken from a verandah at one of the rooms at the left end of the Schoenegg ... Parkhotel Schoenegg.
(That is to say, ask for one of the rooms with the Eiger-side view.) (But look to your left.)
Say hi to Tschingel!


GNUCash how to properly register a "bonus" on a transpit pass/gift card

Question: What is the proper way to record "bonus" money on a card. specifically, when I charge my transit pass for 100, I actually get 150 on the transit pass account. how do I record the extra 50?
Comment: What approaches have you tried? How do you normally record such purchases?
Comment: Right now I just opened a new account and deduct from it but it screws with up with the balance. no idea how to do it better short of what base64 suggested
Comment: What about the 3-account approach I detailed in my answer?
Comment: I tried that, and it generally works it just that the third account shows up in the total net balance and it messed with it so I am looking for something cleaner. its a minor annoyance but still
Comment: What about making the third account an Expense account? That would clean up the balance sheet side of things, and your total Expenses on this transaction would be $100 to match your cash outlay.
Comment: I think you can try Debit Transit Pass Credit Transport Expense $50. That way, no new account is created, and the Total Expense adds up to $100.
Answer: You are paying for your transit it two steps: first, you transfer money from some source account to your card; second, you transfer money from your card to the transit authority. To account for the "bonus", treat it as a transfer from the transit authority to your card.
<code>                      Asset:Bank account     Asset:Transit card      Expenses:Transit
Add money to card          -100                       150                  -50
Went to work                                           -4                    4
Came home from work                                    -4                    4
etc
</code>
By the time you deplete your card, everything balances out: $100 comes out of your bank account; $150 goes on to, then comes off, your transit card; and your total transit expenses are $100.
If you are looking to be more precise, record the extra $50 for what it is: additional government income:
<code>                      Asset:        Asset:       Expenses:     Income:
                    Bank account  Transit card     Transit    Govt travel enticement
Add money to card      -100          150                         -50
Went to work                          -4             4
Came home from work                   -4             4
etc
</code>
Answer: The simplest way is to treat the purchase the same way you treat buying groceries:

Bank account (Asset)
Grocery account (Expenses) - in this case, let's call it "Public Transportation"

Then enter the $100 in the bank account as a withdrawal, make a note in the Description field that you were credited $150, and select "Expenses:Public Transportation" as the Transfer account.

If you want to record $150 in the Public Transportation account, you'll need a third account to catch the extra $50. In your Bank account, enter a new transaction and select "Split" by either clicking the button or using the menu item "Actions | Split Transaction". Then enter these 3 splits in the same transaction:

Transfer: "Assets:Current Assets:Bank Account", Amount $100 in the Withdrawal column
Transfer: "Expenses:Public Transportation", Amount $150 in the Deposit column
Transfer: third account (e.g. "Income:Gifts Received"), Amount $50 in the Withdrawal column.

Note: I'm not an accountant and this isn't financial advice. I'm not sure where the third account should really sit. You'll need to be careful how you treat it when tax-preparation time comes around.
Answer: You do not record the $50 at all.
The Transit Company is offering you a Trade Discount, which is a tactic to induce you to "Buy More". The original price of $150 is arbitrary. Think of it, if a product in the supermarket says Original: $5, now buy 2 get 1 free, do we really enter the free product $5 into accounting system? No.
The only time when you have to enter Discount is Cash Discount. It arises when you buy something on credit, and subsequently the seller gives you a discount only if you pay early. e.g the seller may say if paid within 30 days, 10% would be discounted on the statement.
For more information, you can look up IFRS 15.
For every $1 nominal value you spend on the Transit Pass during the day, you shall Debit Transport Expense and Credit Transit Pass by $0.66.
Comment: I'm aware of the princples,but its for personal review not actual business accounting so no need to be rigid on the rules of accounting. I need something which will show me the data at a glance how much I spent on public transport, how much I have left in the transit pass. the subsidiary is just a simple government subsidiary not related to income level or anything like that.
Comment: I am aware its not actually a discount hence I wrote "bonus" in quotation. its a government subsidiary to promote public transport.

I use it primarly for personal account and not any business need and I'd prefer some method which will let me see my balance in my transit pass at a glance rather than starting to play with the values. it might be wrong in terms of accounting standards but I just need it to keep track of my expenses better. Plus since the subsidary rate is expected to charge around March/April it will just make thing more unclear
Comment: Hi, the principle of accounting is avoid overreporting income, and to avoid underreporting expense. Under this principle, if the subsidy is directly related to the Number of Transit Passes you buy, there is no need to increase both the Income and Expense. However, if the subsidy is based on your income level etc, you can consider it as a reversal of Tax Payment. So based on your intention of relfecting the nominal value of $150, I would suggest Debit Transit Pass and Credit Tax Expense by $50, which is similar to what Lawrence suggested except Gifts Received is replaced with Tax Expense.
Answer: I was given a solution so I am sharing here. By using one of the fake currency (there is a currency called "No Currency") I setup an exchange rate based on the "bonus" and it doesn't interfere with the real currency balance.
Comment: This works, though if they change the bonus to $20, does it increase or decrease the value of the balance on your card?
I think you'd be better off using @chepner's solution.
Comment: @RupertMorrish in that case, the OP would treat it as a change in the exchange rate of the fake currency. This is a good approach. The only situation this doesn't work is the unlikely scenario where the card issuer gives a free bonus (eg Christmas present). In that case, using a third account would work better.


If I rename my computer, will it lead to problems with Ubuntu One?

Question: If I rename my computer by editing the <code>/etc/hostname</code> file as shown here, will I get some synchronization problems with Ubuntu One, which knows my machine as a different name ?
Can I have any other problem I don't think of yet ?
Answer: No, the only problem will be that it will be still listed with the old name. If that inconsistency bothers you you can delete the token and re-sign in to the service.
Answer: Be carefull when changing the hostname, From the IRC #ubuntu channel factoid i quote:
Use hostname  to set the hostname,
 or to do it permanently: edit /etc/hosts to include BOTH the old
 and new hostname and then change /etc/hostname to the new one.
WARNING! Make sure that your current hostname and
 /etc/hosts match, otherwise sudo may not work properly.
I have never had an issue with ubuntu one after changeing hostnames.


Teaching Completing the Square

Question: I'm trying to teach some secondary school students on how to complete the square.  The goal is to rewrite:
$$y = ax^2 + bx + c \ \ \Rightarrow \ \ y = a(x-h)^2 + k$$
The first thing I did was to ask them to confirm, via FOIL:
$$\left( x + \tfrac{b}{2} \right) \left( x + \tfrac{b}{2} \right) \ \ = \ \ x^2 + bx + \tfrac{b^2}{4}$$
With this as a guide, they were able to rewrite something like:
$$y = x^2 + 6x - 10 \ \ \Rightarrow \ \ y = (x + 3)^2 -19$$
Problems occur when the leading coefficient does not equal one.  So far, I am not able to explain why I need to reduce the leading coefficient to $1$ before completing the square.  (Moreover, some of them are having problems with distributions.)  For example:
\begin{align}
y \ \ & = \ \ 2x^2 + 8x - 9 \\
& = \ \ 2(x^2 + 4x - 4.5) \\
& = \ \ 2(x^2 + 4x + 4 - 8.5) \\
& = \ \ 2(x^2 + 4x + 4) - 17 \ \ = \ \ 2(x + 2)^2 - 17
\end{align}
Comment: I find it easier for them to group the two non-constant terms before factoring out the leading coefficient. It doesn't eliminate all difficulty but it's one less thing to worry about.
Comment: My experience with covering this topic is that it is a good one for uncovering the issue discussed [in this question about equals signs](https://matheducators.stackexchange.com/questions/7964/issues-with-equals-where-does-this-come-from-and-how-do-i-combat-it).
Comment: If they're not sure why you factor out the leading coefficient, why don't you ask your students what they'd do instead? Either they come up with a method that also works, or their failure to do so demonstrates the reason why you taught it that way.
Comment: A good way to explain the need to factor out the lead coefficient is to work backwards from the goal. Order of operations has us squaring the binomial $(x-h)$ before multiplying the number in front of it. Thus, working in the other direction, that number has to be factored out before the binomial can be "un-squared".
Comment: I would just refer back to the usual joke about an engineer and mathematician trying to make tea with a kettle, wood stove and water faucet.
Comment: Related: https://matheducators.stackexchange.com/questions/6031/factoring-quadratics-where-the-coefficient-on-the-x2-term-does-not-equal-1
Answer: This may not really answer your question, and, it may be inappropriate to the level of your class, but, I find the idea of looking at an algebraic manipulation algebraically is at times helpful. The whole point of doing algebra is to engage in the kind of thinking I give below so I think there is something to gain from taking this sort of "abstract" approach. The idea here is to discover how arbitrary $h$ and $k$ and indeed $A$ must relate to $a,b,c$ in order that
$$ y = ax^2+bx+c = A(x-h)^2+k. $$
This is itself and algebra problem. Do algebra to do algebra.
Consider
$$ ax^2+bx+c = A(x^2-2xh+h^2)+k $$
or
$$ ax^2+bx+c = Ax^2-2hAx+Ah^2+k $$
requires that these be the same polynomial. Hence, equating coefficients,
$$ \begin{array}{cc} x^2: & a=A \\ x: & b=-2Ah \\ 1: & c = Ah^2+k \end{array} $$
So, the $h$ and $k$ we seek are given by:
$$ A = a, \ \ h = -\frac{b}{2a}, \ \ k = c - \frac{b^2}{4a}. $$
Therefore,
$$ ax^2+bx+c = a\left(x+\frac{b}{2a}\right)^2+c-\frac{b^2}{4a} $$
Then, give numeric examples galore until it sinks in.
It's likely as or more important to explain why it is important to complete the square. Of course the danger of my method, and it is a real danger is that students may black-box this solution. Heaven forbid teachers just say well, you set $h = b/2a$ and $k = c-\frac{b^2}{4a}$ and that's it. The universe in which I present this to a class is the same universe in which the students are also held responsible for reproducing the abstract result in addition to the expectation they do numerically specific examples with ease. Ease born of practice.
Comment: I like this approach; I have used a somewhat similar one as outlined [**here**](https://matheducators.stackexchange.com/a/9709).
Answer: The goals of my approach are:

Emphasize that the purpose of completing the square is a process of writing something that is equal to the original expression.
Emphasize that there are choices to make, differentiating between a choice being useful versus it being true (avoiding the words "correct" or "right" which conflate useful and true).
Avoid unnecessary algebra and quantifiers; my students have a hard enough time with $x$; adding in $b$ and $c$ obscures my previous two goals.

Complete the square: $x^2 + 8x + 19$

First ask yourself: "is it a perfect square?" If it was, you would be able to find two numbers that add up to 8, multiply to 19, and are the same number.
If not, ask yourself what the two numbers would have to be to add to 8 and be the same number. Then recognize that the constant 19 is the wrong constant. Ask yourself: What is the constant you want it to be? Then don't let your dreams be dreams, just write it:

$\begin{align*} & x^2 + 8x + 19 \\ = & x^2 + 8x + 16 \end{align*}$

Notice that this is useful (it factors now) but not true (they aren't equal). Fix what you've written so that it is also true.

$\begin{align*} & x^2 + 8x + 19 \\ = & x^2 + 8x + 16 & + 3\end{align*}$

Then factor the part of the result that you have engineered to work out.

$\begin{align*} & x^2 + 8x + 19 & \\ = & x^2 + 8x + 16 & + 3 \\ = &(x + 4)^2 & + 3\end{align*}$

I have tried a variety of approaches, and I like the abstract skills that this approach allows students to practice. For example, when a student does this:

$\begin{align*} & x^2 + 8x + 19 \\ = & x^2 + 8x + 4 + 15 \end{align*}$

I can ask students if that was a good idea and tease out the distinction that there is a difference between something being true and useful. Since one of the primary goals of algebra courses is convincing students that they have the freedom to do whatever they want when it is true (sure, multiply both sides by 10 if you want man; worst case you can undo it later), this synergizes well with my approach to the rest of algebra.
Answer: I don't know if the following will be of much use to your specific case (our audiences are quite different---I teach this to college freshmen), here is my usual approach:
First, we typically start the quarter by getting a good handle on geometric transformations of graphs of functions.  Given some function $f:\mathbb{R}\to\mathbb{R}$ with a known graph, the graph of the function defined by
$$ x \mapsto B f\left( \frac{x-h}{A} \right) + k $$
is the same as the graph of $f$

shifted right $h$ units (where $h<0$ is a shift to the negative right, or left),
scaled horizontally by a factor of $A$,
reflected across the $y$-axis if $A < 0$,
scaled vertically by a factor of $B$,
reflected across the $x$-axis if $B < 0$, and
shifted up $k$ units (again, down is negative up).

We can then consider the humble parabola defined by $x \mapsto x^2$.  This lovely function has a zero at zero, goes through the points $(1,1)$ and $(-1,1)$, and has inverses on the domains $[0,\infty)$ and $(-\infty,0]$ given by the positive and negative square roots, respectively.
We might first note that if we transform the graph of $x\mapsto x^2$, the two multiplicative constants can be combined:
\begin{equation}
  B\left( \frac{x-h}{A} \right)^2 + k
  = \left( \frac{B}{A^2} \right)(x-h)^2 + k,
\end{equation}
so we may fairly conclude that any transformation of the graph will be given by a function of the form
\begin{equation*}
  x \mapsto C(x-h)^2 + k,
\end{equation*}
where $C$ represents some kind of scaling (we may as well understand it as a vertical scaling, but it combines both the horizontal and vertical scalings into one gooey mess), and $h$ and $k$ are translations, as usual.  In particular, the vertex of this graph is the point $(h,k)$, and the vertex will represent a minimum or maximum for the function, depending on whether $C > 0$ or $C < 0$.
We can also expand this mess in order to obtain
\begin{align}
C\left( x-h \right)^2 + k
 &= C (x^2 - 2hx + h^2) + k \\
 &= \left(C\right)x^2 + \left( -2hC \right)x + \left( h^2C + k\right) \\
 &= ax^2 + bx + c,
\end{align}
which is a more familiar expression to most of my students, as they have mostly seen the material before in high school.  The next "obvious" (for certain values of "obvious") question is:  can we go the other way?
That is, if we are told that
$$ f(x) = ax^2 + bx + c,$$
can we understand the graph of $f$ as the graph of our basic parabola subject to some elementary transformations?  That is, given arbitrary $a,b,c$ (with $a\ne0$), are there $C,h,k$ such that
$$ f(x) = ax^2 + bx + c = C(x-h)+k?$$
The answer is "Yes!", with the details as provided by James S. Cook's answer to this question.
In this exposition, the idea is that the geometry motivates exploration of the problem.  We want to know how to "complete the square" so that we can find the vertex of the transformed parabola, or so that we can determine an inverse on some domain (i.e. solve a quadratic equation).
Comment: Excellent answer as to the "why" we care. Of course, computationally there are so many other reasons once we go on to integration theory, Laplace transforms and pretty much any application which involves a quadratic model symbolically, but, surely graphing is the first and most important application for students to appreciate and master.
Answer: My Approach:
\begin{align}
 y \ \ & = \ \ 2x^2 + 8x - 9 \\
& y+9 = \ \ 2(x^2 + 4x + \underline{\quad}\  ) \\
& y+9+8 = \ \ 2(x^2 + 4x+4) \\
& y+17 = \ \ 2(x^2 + 4x + 4) \\
& y+17 = \ \ 2(x + 2)^2 \\
\end{align}
Notes - Moving the constant to the left in the first step avoids the errors some students might make dividing this number. Now, when you add the '4' to complete the square, you ask "What did we add to the right side?" "4" "don't forget the number to multiply, here, '2', so we added 8 to the right, and we'll add 8 to the left."
Last, the format of that last line is the one I prefer. It's the "Vertex Form" and students can quickly see (-2,-17) is the vertex.
Answer: I present completing the square as a recipe.

Given $x^2 + bx$, add $\big(\frac{b}{2}\big)^2$ to both sides. You obtain a different expression, but your new expression can be written neatly as a perfect square:
\begin{align*}
x^2 + bx &\xrightarrow{\text{add }\left(\frac{b}{2}\right)^2} x^2 + bx + \big(\frac{b}{2}\big)^2 = \big(x + \frac{b}{2}\big)^2
\end{align*}

At some point, I emphasize how important it is that we started with $x^2$ without a (non-one) coefficient: the recipe produces a new expression of the form $(x + \text{something})^2$, which, when expanded, will never produce anything whose $x^2$ term has a non-one coefficient.
So, maybe you can really play up that it's a "faithful, but simple" method that only works for expressions of the form $x^2 + bx$: The recipe deals exclusively with quadratics whose leading term is $1$, end of story.
Note: You face similar problems getting students to factor $2x^2 - 3x + 5$ using the "ac method" or whatever you prefer to call it. Students are used to the process find a pair of numbers that multiply to this, and add to that from the "easy" quadratic case. But, unlike the "easy" case, here we don't just get to jump right to a factorization. Why? Because $(x + \text{thing1})(x + \text{thing2})$ will never produce quadratics whose leading coefficient isn't $1$, and we finally need that. So, we have to add another step or two to the old method.
So I will make a bit of a big deal about the jump from expressions like $x^2 + 6x + 1$ to $2x^2 + 6x + 1$: Our version of completing the square requires us to have just $x^2$. Is all hope lost; do we need a brand new version of completing the square?
This is where I take the approach suggested by DRF's comment: We reduce a superficially new problem to a known, already solved problem. By adding the minor modification of factoring out the leading coefficient, we get the much vaunted $x^2 + [\text{something}]x$ on which our recipe relies.

I'll add that there is a super slick, more general version of completing the square that can handle non-one leading coefficients without factoring/division, given here by André Nicolas (and I think the linked answer is the first place I saw it). It's more appropriate for solving equations by completing the square (instead of rewriting quadratic expressions), but it's so nice that I think it deserves to be more widely-known.
The main idea is that $(2ax + b)^2 = 4a^2x^2 + 4abx + b^2$, so given an expression like $ax^2 + bx$, you'll multiply by $4a$ then add $b^2$, at which point you can write your new expression as a perfect square.
I have yet to mention this for a remedial algebra / precalculus class, but occasionally I'll get a math ed student and show them this method in addition to the usual approach.
Answer: I think it is easier to practice doing this without the y (with the equation set to zero).  Of course it is same thing but for someone just learning, doing it as just a single equation is easier and concentrates the mind on roots.
I would also try to do it very mechanically, writing out each step (like when you are in pre-algebra and first learn how to sort things out with first order equations in X only.)
Just some thoughts.
Comment: I would discourage you from setting the expression equal to zero. Students in algebra classes have enough trouble with the impulse to randomly set things equal to zero as it is, and you calling the expression an "equation" (it has no equals sign unless you set it equal to zero for no reason) is also damaging to their use of precise language.
Comment: The point was to practice it for a while in a simpler situation.  Not giving them the problem as is and then a method of removing the y.  But actually learning it as is with just the X's.  Obviously there are many situations where that formula is exactly all you have. For example the characteristic equation of a 2nd order diffyQ.  Or most chemical equilibrium problems.  Or just deriving the quadratic formula.  Once the student is well practiced at just doing these problems all the time as is, they can execute fine with the y thrown in.

Teaching Completing the Square


Big Data and machine learning to Predictive analytics

Question: This is the first time I post a question here. I am a newbie researcher and want to write a report about Big Data influence on machine learning to improve predictive analytics. I looked through Google for any relevant study shed the light on this subject, but what I found only briefed articles that are not suited to be good resource. Is there any resource I can use through the web as I looked through different libraries and didn't find any good resources relevant? Any help would be much appreciated.
Answer: "The Unreasonable Effectiveness of Data" is an insightful article, written by by some Google researchers in 2010.
If you search for articles that have cited this, you'll find plenty of stuff to read.
Comment: Thank you very much for your post, I liked The Unreasonable Effectiveness of Data" report. It is really knowledgeable
Answer: Predictive Analysis is important to web analytics and useful for predicting what may happen in the future.
You may find this video helpful about Predictive Analytics.
They offer a ton of helpful insight on how predictive analytics fit into the spectrum of analytics and data science, especially when it comes to big data!
Hopefully, this will help clarify!
Best Wishes, Bethany
Answer: Big data is huge in helping accelerate predictive analytics. More specifically, data companies today are using people data to power machine learning algorithms and predictive analytics.
So how do companies incorporate data to improve predictive analytics?

They use data providers to clean and enrich their contact data
adding data points including name, title, phone number, email,
social URLs, and more.
They implement their enriched data into their platform, training
their algorithms to find, and engage customers.
The algorithms provide data and results that enable predictive
analytics to generate insights.


Is the money made with a pirated/cracked softwere halal for me?

Question: I decided to create highly informative videos on islam with a pirated / cracked softwere and release them in youtube. In future if I get money from youtube is that going to be halal for me?
Comment: Its theft so obviously not halal
Answer: That is theft, as you know, which is why you are confused in the first place. At times, the good is separated from the evil so it may be that you will be liable for the theft as a sin, and the good you do is separate. However in this case, it would be surprising if the money will be halal considering that it was initiated by something haram (due to the good being connected directly to the sin, and even occurring only as a result of the sin). I remind you of the following hadith:

عَنْ أَبِي حَازِمٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ
  صلى الله عليه وسلم " أَيُّهَا النَّاسُ إِنَّ اللَّهَ طَيِّبٌ لاَ
  يَقْبَلُ إِلاَّ طَيِّبًا -  Abu Huraira reported Allah's Messenger (ﷺ)
  as saying: "O people, Allah is Good and He therefore, accepts only
  that which is good. ..." (Sahih Muslim).
Comment: I asked a question [Is piracy a form of theft for the purposes of fiqh?](https://islam.stackexchange.com/q/35628/17163) which seems relevant.
Comment: Thanks and answered. For others, it may be worthwhile to look at the link above for a deeper analysis.