How was the Proto-Adamantium in Captain America's shield forged?

Question: I would like to know what combination of ingredients resulted in the formation of Proto-Adamantium?
Comment: The question is NOT a duplicate. And with the additional panels, dates and information provided, it amplifies the previous answer nicely.
Comment: @LightnessRacesinOrbit funnily enough, the OP answered his own question. Seemingly after doing a **HUGE** amount of research. Me thinks it was only asked in the first place so the OP could post his answer. Which is 100% allowed!
Comment: I did not down vote, however the accepted answer on that question gave the same information as this one. Also a simple Google search for Adamantium and or Captain Americas Shield turns up the same information. I'm not knocking either of @Thaddeus answers, just merely pointing out the info could have been obtained elsewhere on this site.
Comment: Why has this question been down voted? It's absolutely not a duplicate of the question @Monty129 suggests.
Comment: "This question does not show any research effort" when you hover over the downvote button. Seems like a pretty good fit, to me.
Comment: @Daft: Oh yeah, didn't spot that. Still, that doesn't make it a good question.
Comment: Yes, I reopened the question because the question that was listed as a duplicate did not give any information about the forging of the shield. Since there are CANON images which give this information right out of the comics, there is no reason it cannot be listed as both answered correctly and effectively by myself OR the original poster who is technically allowed to ask and answer a question if they find the answer themselves. His answer is technically adequate.
Comment: As to whether it is a good question: Looking around the Internet for the year on the topic of Captain America's shield, it is hotly contested in over thirty different sites with widely varying opinions and answers. In my opinion, this makes it a question worthy of both being answered and in my estimation correctly answered, downvotes not withstanding.
Answer: Captain America's circular shield is composed of an unknown alloy dubbed Proto-Adamantium. Technically, the explanation is the material was being designed to be a super-strong metallic alloy that Vibranium was added to. After the scientist creating it took a nap, he woke to discover his mixture of Vibranium-altered meta-material was somehow viable and he poured it into a mold before it hardened.

He later attempted to recreate the process with no apparent success until he stumbled upon his next greatest creation, Adamantium. Virtually indestructible but still apparently no match for his first creation, Proto-Adamantium of which there was only one supply on Earth: Captain America's shield.

Captain America's shield has been destroyed on very few occasions and in its most recent destruction it was reforged by the Dwarves of Asgard with a bit of recently added Uru metal). This has returned the shield to its position as one of the most indestructible items on Marvel's Earth-616, the primary continuity of the comic Marvel Universe.

The shield from the Marvel Cinematic Universe, Earth-199999 is composed entirely of a vibranium metallic alloy. It is proven to be tough enough to survive a strike from Thor's hammer, Mjolnir. It has never been determined if it is as strong as the Proto-Adamantium shield of the comic universe.

In 1981′s Captain America #255, we learn that Cap's shield was the result of a metallurgical accident…

The process that lead to the creation of the circular shield has never been able to be duplicated and the scientist who discovered it would later be credited with the creation of the next best, most indestructible metal of the Marvel Universe, adamantium.

Given that the Dwarven smiths of Asgard were able to reforge and repair the shield, it can be inferred their level of technological capacity exceeds Human technology significantly since Adamantium cannot be forged, altered or even affected by anything less than significant cosmic energy, matter manipulation or reality-altering powers.

Through retroactive continuity, it is established that the shield was presented to Rogers by President Franklin D. Roosevelt. The shield is created by a fictional American metallurgist named Myron MacLain, who had been commissioned by the US government to create an indestructible armor material to aid the war effort. MacLain experiments with the vibration-absorbing metal vibranium. (Captain America vol. 5, #5; May 2005)

During one of his experiments to fuse vibranium with an experimental iron alloy, MacLain falls asleep and awakens to find the experiment a success. This is due to an unknown catalyst entering the process during his slumber, and he is unable to duplicate the result.

The vibranium-iron alloy mix is then poured into a mold for a tank's upper hatch to create the disc shape and painted to become Captain America's symbol. MacLain would later attempt to recreate the shield's metal to no avail, his experiments instead eventually yielding the super-metal adamantium.

The extra-terrestrial material vibranium bestows by nature of the curvature and density of the element within the shield its ability to either deaden or absorb vibration-based energy used against the shield when struck along the front of the shield.

The shield is capable of absorbing incredible energies and preventing them from reaching the wielder. Cap has even used it to absorb the impact of falling from a skyscraper and absorbing the energy of his landing with the shield escaping serious injury.

The adamantium/iron/uru element of the shield supposedly renders the shield relatively invulnerable to almost any energy or effect not considered cosmic or reality-altering in nature.

The nigh-indestructible shield has been broken five or six times, in continuity, by the Molecule Man, Doom, imbued with the Beyonder's powers, Thanos, wielding the Infinity Gauntlet, Thor using the Odinforce and by the Serpent, brother to Odin. Its breaking is usually a monumental event and when its replaced or repaired it is often by the same force that destroys it.

In 1985′s Captain America #303, we meet MacLain again, who, we learn, created Captain America's shield…and yes, in MacLain notes we learn the shield is composed of something-something/vibranium/iron alloy. We are never told what the X-element which allowed proto-adamantium to exist.
Comment: Fun fact: [it is impossible for the Cap' to eat his shield!](http://1.bp.blogspot.com/_e-y-Rrz58H4/TM4QNHdsRlI/AAAAAAAABLA/lXCtyj3SzjE/s1600/DC_Captain_America.jpg)
Comment: @curiousdannii - Could Matter Eater Lad eat Captain America's Shield? http://en.wikipedia.org/wiki/Matter-Eater_Lad
Comment: @curiousdannii if that doesn't show up in Cap 3, I'm going to be incredibly disappointed.
Answer: The exact origin of Pro-Adamantium was never mentioned in comics. But I believe that the unknown catalyst/X-factor in the mixture must have caused a chemical-molecular reaction between Vibranium and the experimental iron alloy. The process must have converted the iron alloy into Proto-Adamantium and at the same time allowing the Vibranium to fuse. That scenario could be the reason behind the existence of Proto-Adamantium.
None of the Adamantium existed before Vibranium. These two metals have a mutual relationship at a molecular level even though they have different physical properties. Since Vibranium can only be fused with Adamantium that includes Proto-Adamantium.
In early days scientists named the shields composition as Vibranium-iron alloy. But now it is referred to as Proto-Adamantium and Vibranium alloy, with the discovery of Proto-Adamantium. It was revealed that the experimental iron alloy ultimately became Proto-Adamantium in the bonding process since there is a historical link between Proto-Adamantium and True Adamantium which resulted accidentally in an attempt to replicate the shield.
According to Marvel Comics Database the official metal found in Captain Americas Shield is Proto-Adamantium and the official composition is Proto-Adamantium and Vibranium alloy. When the shield was reconstructed after being shattered by the Serpent it was infused with the Asgardian metal Uru making it stronger than ever. With the addition of Uru to its composition the shield is now an alloy of Proto-Adamantium, Vibranium and Uru.
Proto-Adamantium is the original Adamantium created by Dr. MacLain. It is even denser and stronger than True Adamantium and it can never be replicated.
The two metals in the shield works in concert with each other. The Vibranium in Cap's shield absorbs vibrations and kinetic energy. At the same time Proto-Adamantium in the shield makes it almost completely impervious. Together these two metals in Captain Americas Shield makes it the most invulnerable item in all of existence in terms of pure durability. Only a godly force can actually damage the shield other than tampering with its molecular structure. The star and stripes of the shield are made of an enamel, that can stand temperatures of up to 9,000 degrees Fahrenheit.
This ultra tough super alloy in the shield has its own unique properties that neither metals (Adamantium or Vibranium) seem to posses. Such as being able to deflect energy waves, including certain mystical energies and being lightweight as well as aerodynamic.
The recent addition of Uru to the shield could have the possibility of carrying an enchantment.
Comment: @Daft [SE encourages answering your own question, even if you already know the answer when asking it](http://scifi.stackexchange.com/help/self-answer).
Comment: @phantom42 ah I see. I didn't know that.
Comment: Did you only ask the question so you could post this answer?


Is there a way to prove to a third party that you are the recipient of a transaction?

Question: Let's say that someone sends me some ETH. How can I prove to a third party that I am the actual recipient of that transaction?
The third party is anyone with access to the blockchain. In other words, I want to send some data to this third party that allows it to verify that I am the recipient of a specific transaction on the blockchain.
Comment: This question needs a lot more detail. Who needs to prove? What is the proof method? (ie. address, hash, etc.) Is the third-party a contract?
Comment: @ReyHaynes added details
Comment: Why can't you just send a transaction from the same address which received the original transaction?
Answer: You could sign a message hash using the private key of the account that received the transaction. ecrecover can be used to verify the signature was generated from that account.


MPU6050 raw sensor data, zero

Question: I am trying to get raw values of ACCEL_OUT from MPU6050 (GY-521 module). I can read WHO_AM_I register and I can write to PWR_MGM_1 (0x6B) register and change it default value from 0x40 to 0x00 ( when I write to register, I can read 0x00). and interrupts are handled fair, I need to access raw data of sensors. but when I read ACCEL_OUT registers, for example (ACCEL_ZOUT_L) it just return 0x00. I spend a whole night and a whole day on this problem and nothing good happened at all.
Any advise would be great help.
Thnx.
Answer: I solved the problem, it was I2C NACK and STOP in read command.
Comment: Could you elaborate on this? What did you do to fix the problem?

MPU6050 raw sensor data, zero


Why is there so much interest on home loans?

Question: Search around the internet for current mortgage rates and play with some of the amortization calculators. You'll see that at the end of the payment schedule you will be paying almost an equal amount in interest as you do in principle. I want to know why financing entities advertise their loans with less than 6% interest/apr/rate, but end up charging you nearly 100% of the borrowed amount in interest by the end of the schedule. What gives? I thought that at the end of a loan for $100,000 at 6% interest meant you will only pay $106,000 total, not the $195,000 that the amortization calculators suggest.
Comment: Short answer: Because the term of the loan is so long.
Comment: Did you not learn about compound interest in school?
Comment: If you make no repayments during the year and then pay the full $106,000 on the last day of the first year then you will only pay a total of $106,000 (not including any fees), but most people don't pay loans off in this manner, the rate quoted is p.a (per annum).
Comment: Is your question about the discrepancy between the listed number (annual interest rate) and the actual amount paid, or are you asking why so much interest is charged at all?
Comment: My question was about how APR or Interest is applied. I understood before it was applied once to the entire loan term and paid off over the term. Here I'm finding out it's applied every year and must be fully paid every year.
Comment: Pretty funny question. If you take a mortgage for one year, then your expectations will be met. Sorry but could not get past this question)
Answer: APR stands for "annual percentage rate." This means when you see a loan with a 6% rate, it is 6% per year.  On a $100,000 mortgage, where you aren't paying much of the principal down at first, a 6% rate would have you paying nearly $6,000 in interest in the first year alone.
Comment: @CodeSeven You are charged interest on whatever is left of the principal of the loan. As the principal of the loan gets paid off during the term, you get charged less interest, and more of your payments go toward paying off the principal. Therefore, the total amount of interest you will pay during the loan depends on how long the term is.
Comment: @CodeSeven yes, you are completely wrong to assume that Annual Percentage Yield actually means different things depending on the asset securing the loan
Comment: So to verify, googling today's rates you have 3.659% APR. total interest and fees paid at the end of the term is essentially 109% (3.659 x 30) of the borrowed amount?  And am I wrong to assume that an auto loan is only 6% overall? Is that also really 6 or whatever % of the principal amount being charged every year?
Answer: Interest rates are always given annually, to make them comparable.
If you prefer to calculate the rate or the total interest for the complete time, like 10 years or 15 years or 30 years, it is simple math, and it tells you the total you will pay, but it is not helpful for picking the better or even the right offer for your situation.
Compare it to your car's gas mileage- what sense does it make to provide the information that a car will use 5000 gallons of gas over its lifetime? Is that better than a car that uses 6000 gallons (but may live 2 years longer?)
Comment: Note that it is simple math, but it is NOT just multiplying the interest by the number of years of the loan. Remember, this is compound interest. Aganju doesn't imply otherwise, I'm just clarifying.


If I wasn't invited to the shareholder' meeting but now I do own stock in the company, can I still attend?

Question: There's a company whose shareholder meeting I'd like to attend. The official notice says that only shareholders of record at a given date are invited and can vote. I acquired shares after that date but before the meeting date. Can I still attend the meeting? I don't want to vote, only ask some questions.
Comment: Does the official notice have any contact details? You're probably best asking the organisers ... the cut-off date may be legal/regulatory, but may be more of a logistical thing.
Comment: If you actually want to get information, you can ask their investor relations department anytime without waiting for a meeting, and regardless of the date you bought. If your goal actually is to confront or embarass the managers as a publicity stunt or similar, you're wasting your time; almost none of the attendees will give a fig, and the handful who do will be as quixotic and ineffective as you.
Comment: Usually everyone is invited who owns shares on date X. The date X may be on the day of the shareholder meeting, or later, or earlier. So it depends on whether you owned the shares before that date, not the date of the invitation.
Answer: This would depend on the company law of the jurisdiction. However, in most cases to be a valid shareholder your name needs to be registered in the company's shareholder books. In your case, since you were not registered, there is no provision by which you could be deemed a shareholder and probably will not be able to attend the meeting as a shareholder. The registration on the books is also important for other matters like dividend payment etc.
However, in your case, you may write to the company if you can  be allowed to attend the meeting in other capacity, for example as an observer, however, that would depend on the company law, if it allows such provision and the willingness of the company to accommodate such request.
However, there is no harm asking, you could speak to them and find out.


Align 1,500 Time-Lapse Pictures

Question: I took 1,500 pictures of a scene but unfortunately the tripod was not stable.
When I rendered the video, it did not look good.
I tried to aligning with the help of Photoshop, but wasn't successful.
I tried stack function, it took too long and in the end it crashed.
Then I opened all images in layers and tried auto align function, but no luck there either.
Is there some easy way to align all images?
Maybe someway to align all images to one image and then crop, or some other way.
Comment: If each shot has movement, auto aligning in PS will not work, since the software cannot "know" which parts of the image should be still and which should be moving. I think you would either have to align them manually, or fix the tripod and shoot again, or perhaps use a video editor and attempt some kind of video stabilization.
Comment: Adobe After Effects will do the job as mentioned in the Answers below as well as other software with a tracking capability. When you finish, the stabilized and software-aligned portion of the sequence will be cropped (clipped) from the viewable area as it is not common to all processed frames. The amount of clipping will be comparable to the amount of tripod-instability
Comment: @Stan I used this technique but with adobe premiere pro. thanks for the answer.
Answer: Thank you all for the helpful responses. I solved the problem with the help of your answers.
Since I took help form you answers but there was not a complete solution, so I decided to post the complete solution by myself.
1) Import image sequence to adobe premiere pro (CC 2017 in my case). Premiere will make one video file out of all images instead of importing all images.
2) you can right click on the imported file and change the sequence properties as desired. (I changed the frame rate to 60fps).
3) move sequence to the editing panel.
4) search for the "warp stabilizer" in the effects, and drag it over your video. it will take some time to analyze but not very long. then it will stabilize the movements from the time-laps video.
5) In the effect setting apply no-motion in the result. so that the stabilized video will be still and focused on one scene.
(Remember it is the movement caused by shaky tripod. that is why you do not want any motion in the stabilization.)
6) Go to file > export > media. There you can select the quality and format.
Hope it was helpful.
Answer: If I understand correctly you are trying to stabilize the sequence of images. Use editing or compositing software like Fusion, Nuke, After Effects... There you can track some points and stabilize the sequence.
Comment: Or specialized tracking application like syntheyes.
Comment: I think the software feature required is typically called either "image stabilization" or "motion interpolation"
Comment: @Yorik Thanks for the tip. adobe premiere pro did the trick for me.
Answer: Using Photoshop, if you set a layer to difference, you will see where it differs from the layer under. So you could import your images in Photoshop, find a place that doesn't move in your time lap and use this as a reference point. Then export as an animated GIF, or crop and re-exported as stable images. However this might be quite too time consuming if you need to rotate images and not just move them horizontally/vertically.

Align 1,500 Time-Lapse Pictures


Contacts visibility to site guest user

Question: My site guest user needs access for all the contacts in the instance. Right now site guest users can access contacts created by guest user. They are not able to access contacts created by Salesforce users. OWD setting for Contact is Public Read/Write. I don't want to change the OWD at this moment.
Answer: It seems that you imply Default Internal Access OWD when you mention OWD setting for Contact is Public Read/Write. The Guest User is by definition an external type of user. So what you need basically is: (1) Enable External Sharing Model; (2) set Default External Access for Contact as Public Read/Write.
Refer to this official documentation External Organization-Wide Defaults Overview for more detail.

Contacts visibility to site guest user


Does a session beer have to be below a specific ABV?

Question: Does anyone know if a "session beer" has to be below a specific ABV to qualify as a session beer?
Answer: Like many beer terms, "session beer" is not rigorously defined.  Several groups have tried, though:

The Brewers Association (PDF) called it 4.0-5.1% ABV
Beer Advocate calls it less than 5%
The Session Beer Project calls it 4.5%.

Really, though, if you call something a session beer, most people will understand that to mean something you could easily drink several of in a session (ie, lighter and more mild than a "big" beer).
Comment: 5%?   If I attempt a session on Courage Directors, (4.9%), it gets auto-terminated after 5-6 pints.  I would go with the Brewewrs Association figure - I can drink Doombar, (4.0%), all day, (mostly, anyway:).


Help on transferFrom and Approve functions

Question: We have a token contract A and an Escrow contract B. While transferring token from an address to contract B we are using transferFrom function which overridden from contract A. But in need to do the transfer , we have to call approve function on contract A. This works if we call the approve function directly from contract A. But if we are overriding the approve function just like transferFrom on contract B, it is failing. Could someone please explain how we can call approve from contract B itself.
Comment: what do you want to approve?, if you want to approve tokens in the contract b to be moved by someone else, this will work. But if you want to approve tokens of user X to be moved by user Y from contract B this won't work, could you please clarify?
Comment: User X have contract A tokens. Using Escrow contract (B) , X wants transfer tokens to either Contract B or User Y. But without calling Approve function from Contract A, this is not working. It works only if the User X , calls the approve function of Contract A directly. We are trying override the approve call inside Contract B and its not working.
Is it because, even if the User X calls the approve function from contract B, the msg.sender returned inside the contract A is the contract B address instead of User X address?
Comment: why do you need approve or transfers to be done form contact B. If B is an escrow, then users send the tokens to B and then when the conditions are meet, B will send to the users. I think you just need to ask users to send tokens to B and the B do the rest
Comment: Escrow Contract (B) has a function transferFrom(address _from, address _to, uint256 _value) which allows us to make the user X send tokens from his address to user Y. We are trying to use it. But when a User X connect it using Web3js, User X has to make call the approve function in Contract A with the token address as param atleast once to allow transfer of the token from User X address to the Escrow contract.
Answer: If you want to approve tokens in the contract b to be moved by someone else, this will work. But if you want to approve tokens of user X to be moved by user Y from contract B this won't work. The issue is that calling approve from contract B will have as msg.sender and it will fail.
Hope this helps
Answer: The rule is: you can approve the future spending of your tokens only. This is assured checking implicitly that msg.sender be the owner of the tokens "approved".
If Escrow B want to approve something, it can only approve tokens on Escrow B's account (I.e. owned by the 0x... address at which the Escrow results deployed).
No other possibilities do exist (if we are talking about ERC20).
You should need that a forceTransfer function in the token contract 1) do exists; 2) is accessible by you; in order to be able to do something different.
Any function you write or find written or you design in the Escrow cannot do nothing different from the standard described above, because the tokens reside and are managed in the internal storage of the tokens contract only, by the tokens contract only. Outside of it you can only interact with it, but no tokens exit from their contract.


Differences between 'up to now' and 'so far'

Question: Is there any Difference between 'up to now' and 'so far' except to the condition when 'So is' is used for 'distance' in the sentence ? I would be greatfull if anyone would tell me,thanks
Answer: In most situations they are interchangeable. According to this NGram, so far seems to be significantly more common than up to now.
In situations where something is coming to an end, there may be a preference for up to now, whereas so far implies that the situation will continue:

Meals in the staff canteen have been subsidised up to now, but from January the subsidy will be withdrawn.
The festival has been pretty good so far- let's hope it stays that way!
Comment: I agree with this as American English as well. I think "up to now" is really a spinoff of "up until now", implying the situation has ended. "Things were going great, up until now." "So far" suggests the current situation is ongoing. "Things are going great, so far."
Comment: Are you not sure of your answer as you have used 'may' ?
Comment: I use 'may' because English is not always exact: usage varies between individual English speakers. YMMV.
Comment: Are you talking abt America or british English ?
Comment: British English. My own experience and this. http://english.stackexchange.com/questions/259169/up-to-now-vs-until-now


From mining to sending via RPC

Question: Assuming that there is a magical mineblocks RPC command that can mine X blocks on demand, what is the complete set of command line commands to start a client, mine my coins to a specific address, see the mined blocks, get the reward and send them to an address XXX?
Answer:
Put your client into regtest mode. This allows you to mine an arbitrary amount of blocks very quickly. Add this to your bitcoin.conf
regtest=1
daemon=1

Generate the blocks. Run
bitcoin-cli setgenerate true <number of blocks>

where X is the number of block you want. You'll want at least 101 blocks.
See the mined blocks. Run
bitcoin-cli getblockhash <index>

to get the hash of block number <index>. Then take that hash and run
bitcoin-cli getblock <hash>

Repeat Step 3 for each block you want.
Send the Bitcoins to a new address. Run
bitcoin-cli getbalance

to find out your balance. Run
bitcoin-cli sendtoaddress <address> <amount>

If you don't need to see the contents of the block, you can skip steps 3 and 4.
Answer: setgenerate has been removed. and now you can use generatetoaddress to mine.
# generatetoaddress
generatetoaddress 1 2NDyXhf4i44Vqpy9FvPHXkw8ccA2WtMkTe3

From mining to sending via RPC


Apple Watch: Can it be configured to only send outgoing calls?

Question: I would like to configure an Apple Watch so that it can only send outgoing phone calls. The Watch would be for my elderly mother, so the ability to call for help (especially if the Watch detects a fall) is invaluable. Naturally, I do not want any inbound calls to go to the Apple Watch and bother the wearer, as it would be tied to my TMO cellular service.

Can the cellular Apple Watch be configured to only send outgoing
calls?
Can the watch be configured to not "ring" when calls are received?
Can the watch be configured to not notify when SMS messages are received?

If you have a device and have configured it as said, please state this in your response.
Answer: I don't think the Apple Watch can be configured like this, but you might take a look at Use Emergency SOS on your Apple Watch.


Japanese font to match copperplate

Question: I need to find a japanese font that matches copperplate in english. would be grateful for any help. Thanks in advance.
Answer: If you are looking to match the serifs Mincho would be a good place to start.
It's one of the more traditional Japanese fonts.

Matching fonts between languages is tricky because there are requirements for how characters are used and laid-out.
Answer: I could not find a good match, but for those kind of serifs,

I can only suggest this:

though is too curly...
Anyway, if you are interested, the typeface is 優雅宋 Std W5 [ゆうがそう] (Yuugasou Std W5) from DynaComWare. I will keep looking for a better match.

Japanese font to match copperplate


Polar vs. Amphipathic

Question: How can I tell if a molecule is purely polar or amphipathic?
For example, fatty acids are amphipathic because they have a polar carboxyl group and a non polar chain of hydrocarbons. However, sometimes there are molecules that have hydrocarbon chains and side polar groups but are categorized as polar.
What is it that I should look for?
Thank you so much!
Answer: The answer is that it is a sliding scale. There is no such thing as "purely polar" or "purely nonpolar." Water is very polar and hydrocarbons are very nonpolar, but there is no clear dividing line between the two categories.
Further confusion in biological molecules such as amino acids can occur, because different individuals categorize them in different ways, considering either just the side chain or the whole molecule. For example the amino acids have the formula $\ce{H2N-CHR-COOH}$ and in the simplest case, Glycine, R=$\ce{H}$. This is clearly a very non polar side chain, but the molecule as a whole is mostly polar, as the side chain is such an insignificantly small part of the molecule. Thus authors who categorize amino acids by side chain (mainly chemists) put Glycine into the non polar category, while authors who categorize amino acids by the whole molecule (mainly biochemists and biologists) put it into the polar category. When it comes to Alanine, R=$\ce{CH3}$ all authors agree it has a non polar side chain and most seem to categorize it as a non polar molecule.
A simple search of the internet shows that there is very little agreement about the amino acid Tyrosine, R=$\ce{CH2-(C6H4)-OH}$. It is classified as polar, non polar, having a polar side chain and having a non polar side chain by different authors. Clearly it has some characteristics of both, having both a benzene ring and a hydroxyl group. The correct definition would be "moderately polar."
You might hope that it is possible to give molecules a number which describes their polarity. This can be done to some extent. Googling "solvents by polarity" will give you lists for common solvents. This is, however, complicated if the molecule of interest happens to be acidic or basic. An acidic molecule will be polar in acidic solution but will become charged (and therefore much more polar) in basic solution, due to loss of $\ce{H+}$. Similarly, a basic molecule will be polar in basic solution but will become charged (and therefore much more polar) in acidic solution due to gain of $\ce{H+}$.
An amphipathic or amphiphilic molecule has a part that is highly polar and a part that is highly non polar. These terms also generally mean not just a molecule that is moderately polar, but one in which there is some distance between the polar and non polar parts, so the molecular weight would be at least into the hundreds.
The example you give of a fatty acid is a good one. (The deprotonated, negatively charged fatty acid anion in basic solution would be an even better one.) Another example would be many cell membrane proteins, which have a non polar, hydrophobic part (that stays in the cell membrane) and polar, hydrophilic parts (that extend out into the aqueous media inside and outside the cell.)
In summary, different substances should not be pigeonholed as polar or non polar as it would require that you draw an arbitrary line, but in general the polarity of two different substances can be compared fairly objectively. And pH may make a difference.
Comment: Good thorough answer in my opinion! I made some formatting changes based on the formatting criteria discussed [here](http://meta.chemistry.stackexchange.com/questions/86/how-can-i-format-math-chemistry-expressions-here). It's very well written and makes for a good primer/guideline.

Polar vs. Amphipathic


Apex batch job performance

Question: I am salesforce admin currently facing performance issue with one of the 3rd party(classy-SF) Integration. Batch job installed from classy are running 300+ times in 24 hours( batch size 1).Each batch job taking 3-5secs.  There are 4-5mins queuing/holding between 2 run as there are other batch job running at that time. This batch job is processing 500-600 Inbound API request . There are approximately 8k API request  waiting in queue + 1k new incoming API request everyday . At this rate, the API request to be processed growing every day, batch job is processing at one month lag .
All batch job are from managed package from provider.  What best I can do to solve this issue? Any suggestion plz.
Answer: You might not be able to do anything, at least not without help from the vendor. It should easily be possible to run 15,000 batch executions a day at 5 seconds each. The ideal solution would be to reset the batch to a higher scope size.
You should be able to set it to 20 or so, assuming the code supports it.Even with the 4-5 minute wait between each execution, you're looking at being able to support 6000 records a day instead of just 300.
If you can't modify the scope size, and you need all your batches, then something has to give; one of the vendors will need to fix their code so they can happily co-exist. The resource limits in place are there for a reason (so everyone has a snappy Salesforce experience), so the code has to run within those limitations.
Comment: Thank you so much for the quick response.  I believe scope size 1 for some reason It's doing update/create on 3-5 major object. Although I check will check with them.
Comment: @AthimathiSachithanandam Yes, like I said, the vendor may have to optimize their code. The ideal situation for you is to be able to increase the scope size as much as possible.
Comment: @AthimathiSachithanandam I saw your comment (but comments do not belong in answers). The platform automatically allocates resources to all orgs that have asynchronous code, plus future/queueable/scheduled methods, so requesting additional resources are not going to help. You're going to need to look at your overall org structure. And yes, I know vendors like to point fingers elsewhere, but I can almost guarantee that at least one of them are guilty of bad code writing.
Comment: Sorry new to this website.I am assuming i can comment here for further clarification.. thanks,It gives me lot of insight .. My job here to point out guilty party...Apart from increasing scope, I am trying to reduce in between 4-5mins gap. I see another schedule job in queue 1-2mins  before processing(no there job in queue). only possible way  to monitor is log. I have no idea how to monitor that 1-2mins gap. Any suggestion helps..thanks
Answer: There was an "ApexToken" stuck in "Queue" for long time. After deleting, the batch job processed increase dramatically.

Apex batch job performance


Is it reasonable for a client to expect automated test scripts as project deliverables?

Question: Our company is currently halfway through a software project with a consulting firm. As someone who will be taking ownership of the project after the consultants finish, is it reasonable for our company to ask the consultants to write automated test scripts and pass them on to us?
Comment: As the client, you can ask for anything you want. However, if the contractor will agree is another story. Did you discuss automated scripts as part of the deliverable upfront?
Comment: It depends on you(the client). Generally, such issues are decided at the start of the project in a document. But, if you and your consulting firm have a good rapport, you can ask them even now and they might oblige. If not, you may be asked to pay extra.
Comment: It's perfectly reasonable, assuming that that's what you've paid for.
Answer: Usually the project deliverables are established at the start of the project in the project scope. The contractor uses this scope to establish the cost of the project.
If you didn't mention automated test scripts at the beginning in the scope, then the cost of the project didn't include those as deliverables.*
Asking for extra deliverables after the scope has been established is called scope creep. You can ask the contractor if they could include these, and the additional cost of doing so, however the contractor is not obligated to agree to your new terms.
* Unless the contractor can read minds. In which case, keep them!
Answer: Always and always, check in the scope document.
But in general, tests are NOT part of the regular development as they are a story on its own. I never offer them and from 10 clients I mention tests, maybe 1 to zero will tell me to code them.
But just in case for the future, always mention tests and ask the client if he wants them.


How does one use cocoa butter in cooking?

Question: I'm experimenting with different vegan solid fats for baked goods, like pancakes.  This fat isn't only solid at room temperature, it's hard as a rock even on a warm summer day.  For baked goods, do I need to do any adjustments to the recipe, or do I just microwave it until it melts and use it like butter?
Answer: Cocoa butter has an exceptionally high melting point for a vegan lipid.
For most baking applications, it probably not ideal; you would be better served with a liquid oil, or if you need something solid but malleable, a hydrogenated vegetable oil product like a vegan margarine.
The main culinary use (in general) is thinning chocolate in creating chocolate coated candies or similar, which makes sense as cocoa butter is one of the primary components in chocolate.  Of course, when it is hardens and is in temper, it is literally as hard as chocolate.
Otherwise, you can fry or saute with it, although it would be easier to do so if you purchase cocoa butter grated as it is normally too hard to scoop at room temperature.
If you melt it (and it will melt just below body temperature), you could bake with it, but you may get a different texture than you expect, as when cool, it is much harder than other typical culinary fats.  You will have to experiment and see what the results are like.
It will be too hard to use with creaming method recipes.
Comment: The texture comment is dead on. A fat as solid as cocoa butter will make most baked goods seem very stale, because it will harden the crumb much more than you're used to.
Comment: @sourd'oh The idea of cocoa butter as a substitute for butter is intriguing. What if you mixed melted cocoa butter with something like canola oil and then baked with the mixture? With appropriate added water...
Comment: @Jolenealaska I think that is doable. I worked one place where the owner made a super secret white chocolate cake. While the recipe was kept from the minions like myself, I always suspected that thinning cocoa butter with oil was the basis of the cake. (And seriously, the cake was amazing. It was kind of firm, but it literally melted in your mouth.)
Answer: mix cacao butter with coconut butter - just as you would for making raw chocolate.  makes a great spread for toast etc and is fine for baking, especially cookies, but you might need to keep mixing to keep it warm and pliable.
coconut butter makes the best butter substitute
For goodness sake don't use margarine or hydrogenated oil - that stuff is just a few molecules away from being the tub it comes in - it's certainly not food!


remove the script in init.d

Question: I want to flash TweakDrypT to my rooted android 4.4.2 device. But before, I must delete all the scripts in init.d. I've tried using universal init.d to remove them, but they won't. Anyone can help?
Comment: One urgent hint: Make sure to do a backup first, a *complete* one (see: [nandroid](http://android.stackexchange.com/tags/nandroid/info)). That's always the first to do before modifying things in `/system`. 2nd: I don't know why you "must delete all the scripts in init.d" (some background would be helpful; this might well be an [XY problem](http://meta.stackoverflow.com/q/66377/192154) ;) But before *removing* them, make sure you have a copy (see: backup). If things go nuts, you might need them again.
Answer: Just use any root file manager like root browser and browse to system/etc/init.d and delete all scripts manually
Alternatively, download and install terminal emulator. Open it and enter these commands One by One->
su
mount -o rw,remount /system
mkdir /sdcard/init/
cp /system/etc/init.d /sdcard/init/
rm -r /system/etc/init.d/*

In first command, we gain the superuser rights. It should request you for root permission, grant it if it does. The second command is to mount the /system (partition where init.d scripts reside). And third command creates a new folder "init" in root of internal sdcard (this is where we will backup your scripts in case you will ever need them). The fourth command copies all scripts to folder we created in third step (backup). Fifth command finally removes all files inside init.d folder.
Hope this helps.
Comment: and again alternatively, use ADB: `adb shell su -c "mount -o remount,rw /system && cp -a /system/etc/init.d /sdcard && rm -rf /system/etc/init.d/* && mount -o remount,ro / system"`. // Note: do **NOT** use `*.*`, as that would only remove files with a `.` in their name. This is not Windows ;) And don't forget to backup first. Might need that later when things go weird ;)
Comment: Thanks for suggestions, I added the details to answer :)
Comment: And I upvoted it meanwhile. Warning for the missing first step (backup) is in my comments :) // Oops: typo in my first comment to your answer: at the end of the command, there must be NO space between `/` and `system` …

remove the script in init.d


Why use C# code inline?

Question: I was once asked in an interview "What is the reason for using C# code inline in an aspx page". I couldn't answer, so I'm curious. Why would you do that instead of using code behind? Is there a technical reason?
Answer: For ASP .NET WebForms
It is not a generally recommended practice to write inline code because WebForms make heavy use of "controls" that generate HTML output and presentation logic is expected to be handled by them. For example, to iterate over a data array you would rather use asp:Repeater than foreach loop. Using a loop in this case would smell bad and remind of classic ASP days when markup and code were mixed like a spaghetti. I can only think of using Response.Write inline to output debug messages.
For ASP .NET MVC
It's a totally different situation here. Because MVC discourages using "controls"  in favor of clean, hand-coded HTML markup, inline code is the preferred way of generating HTML for model views. Of course, it also depends on what exactly you are doing in the inline code. My rule of thumb is use inline code when all data needed to render the view is made readily available by the controller. Inline code should only contain presentation logic, such as showing or hiding a field based on condition, getting a string from resources, enumerating over an array in the model, etc. You should never talk with the database from the view—this is what controller is for.
Some people don't feel comfortable using inline code in ASP .NET MVC because they have learned that "inline code is bad" when programming WebForms. This is a misconception, and my answer to it is inline code is only bad when it does something other than presentation logic. In WebForms this logic is handled by controls, in MVC—by the inline code, so there is no real problem here.
Comment: Thanks, that's the kind of detailed, reasonable explanation I was looking for.
Comment: I really like, "inline code is only bad when it does something other than presentation logic". Now _that_'s something I can remember!
Answer: I'd answer with the stereotypical "it depends"..
I would write inline C# (and frequently do) if it's a pure View concern.
It's a common pattern with MVC applications to do complex display-related stuff by using simple C# in your views..
If the code in question strictly relates to rendering the data onto the page inline C# may very well be the simplest and easiest solution (unless you use WebForms where nothing is simple). If the code is not strictly related to rendering data I'd seperate the rendering part from the processing part and only use the rendering code in the view.

Why use C# code inline?


Looking for smallest set of rows that form a natural key in a data set

Question: I have several sets of text files on hdfs that are exports from relations.  Unfortunately I do not know the structure of the table is, but I do know that each has a multi-part key that defines a row uniquely.  I know through domain knowledge that the key is multi-part (e.g. reporting-date, and item number) and I can identify some columns that are clearly not in the key (e.g. revenue from sale).  What is an effective way to identify potential sets of columns that are natural keys, because they are not duplicated in the observed data?  I can get several days of logs in a few Gig, so python or sql could work.  This seems like an great application for a dictionary, but I am not sure how to approach this.
Answer: You could do this a few ways...

write a script that does the following.

pick a table,

get number of rows in the table, can do this as you go. (+=1 in loop)

select several fields(columns) in table that you think may form the key,

create empty Set()

burn through the file row by row, for each row grab the target fields and construct a string key str(field1)+'_'+str(field2)..etc.  Add this key to your set.

when you're done going through all rows of a table, check len(set).  If the key you picked is good then len(set) will equal # rows.

Another way, and this will depend on what you want to do with your data and how often you will access it...is to import it into a sql database.  I usually use mysql. Once your data is in:

select count(*) from table_name;  will give you rows in table

select count(distinct field1, field2, field3) from table;  gives number of distinct combos of field1+field2+field3

if the two selects give the same number then you have a key that works. It may not guarantee a join-key but it will be unique to that table and will help the linking process.

many people highly advocate the use of pandas. If you get the data imported into arrays you can create a dataframe and do some queries similar to SQL.  I'm not super familiar with pandas so I can't give an example.

If it's a one-off, I'd make a python script.  But if you think you'll be exploring the data further, spending the time to put the data in a database could be useful.


"You've gained the privilege" notification without actually gaining the privilege - bug?

Question: I currently have 6 rep, and just got notifications for ELU saying, "Congrats, you've gained the privilege - ..." for things like remove new user restrictions (requires 10), vote up (15), and talk in chat (20). I tested up-voting an answer (on the main site) and couldn't (as expected). What reason might there be for the notifications?
Comment: @Mari-LouA Could participate in meta, at least.If the downvoter could comment so that I can improve whatever they felt was wrong with my question, it would be much appreciated. I've seen similar questions where the issue was a quick un-upvote, but that wouldn't have put me anywhere near 20...
Comment: Michelle, where did you try upvoting, here or on the main site? As far as I remind, upvoting here require at least  25 rep-points, though.
Comment: @Carlo_R. On the main site. The usual "requires at least 15 rep" message popped up. I also got a notification for "talk in chat," which requires 20.
Comment: Michelle, maybe the system use the present tense to talk about the future.
Comment: Don't understand the downvote myself but here is the list of privileges and their corresponding points. http://english.stackexchange.com/help/privileges According to the list, you can (for now) only participate in meta.
Comment: I'm upvoting your question because it's a relevant one. It could be that it was or is a bug.
Answer: My guess is that your answer got accepted, which added 15 points to your rep, but then the O.P. opted to change that, and accept a different answer. If that was the case, you may have lost the points, but I don't believe SE revokes the privileges.
A 15-point swing would explain how you jumped from 6 to over 20 and then back to 6, especially since your answer doesn't have any downvotes.
Moreover, I noticed that you answered a question posed by a newer user; I've also observed that newer users are often prone to quickly accept the first answer given, and then change that when an answer they like better gets posted later. (In my mind, there's nothing wrong with that practice, although I recommend not accepting an answer for at least 12 hours, and maybe even waiting at least a full day or so, to let a good number of users get a look at the question before deeming the matter "settled.")
Comment: It didn't even occur to me that my answer might have been accepted, but that makes total sense. Thank you! I wonder whether it would be useful for SE to list "revoked" rep events (just for the user) on profiles, i.e., 0 points and a grayed-out description followed by (revoked) or something.
Comment: Sometimes "-15 answer unaccepted" _can_ be seen in your reputation report. Depending on how fast the O.P. changes their mind, though, even that might not show up. Personally, I wouldn't worry much about these small fluctuations.
Comment: @J.R.; It's easier 'not to worry about small fluctuations' when your rep has a k in it.
Comment: @Tim: All I meant was that rep goes up and down on occasion for hard-to-explain reasons: questions get deleted, users get deleted, people change accepted answers, etc. This [isn't the first meta question](http://meta.english.stackexchange.com/questions/2818) I've seen asking, "Why is my rep off by a few points?" I stand by my advice, irrespective of what SE I'm on (FWIW, I'm missing the 'k' in [all but two](http://stackexchange.com/users/1257562/j-r?tab=accounts)).
Answer: The notification message is created when you reach the reputation required for a privilege, but the notification message is not removed when the reputation becomes lower than the required reputation.
A reputation could decrease because down-votes, the user offering a bounty, or another user changing idea on the accepted answer and accepting another one. In all those cases, if the reputation is decreased before the user has seen the notification about the new privilege, the user will read something that is not anymore true, until the user doesn't get more reputation. The notification about a new privilege is shown only once. This means that, if your reputation oscillates around the value required for a privilege, you will not keep to being notified.


How do you get a low poly exterior from a high poly model?

Question: I imported an obj model of a truck made by someone else in a different 3D program but it is outrageously huge; it exceeds 2 GB and none of the vertices are connected together so I can't use the 'L' key in edit mode to select connected vertices. I also tried using decimate and limited dissolve but both of them made the object unrecognizable and weird. Is there any way to just get the exterior of the truck (without using decimate/limited dissolve) without remaking it entirely? The other person made the file using Catia so I'm not sure how the export settings for that program would work. I tried manually removing and combining the vertices in edit mode, but it almost always crashes my program since it lags a lot.
Answer: Solution 1 - Shrinkwrap
You might have some success with the Shrinkwrap-Modifier. Create a cube that completely surounds your high-poly object, apply it's scale, subdivide it a couple of times to give the modifier some vertices to work with, and then use the Shrinkwrap modifier on it with the high poly truck as the target. The modifier should wrap your cube around the outer surface of the truck. When you're happy with the result, apply the modifier.
Solution 2 - Manual Retopology
The Shrinkwrap modifier doesn't give you very much control over the result. So even though you're looking for an answer that doesn't require you to model the truck a second time, that might be the best solution.
Use either the result of the shrink-wrap or the original truck model to model a very low-poly version of the truck over the existing base. This process also works if your viewport is lagging due to the huge number of polygons involved - you can simply delete the parts of the truck you're currently not working on to reduce the strain on your hardware, and re-import the full truck once you're ready to work on a part you've deleted.
Make the low-poly model it slightly bigger than the underlying high-poly geometry (or you might want to use Snap to Faces to stay as close to the original surface as possible). Once you have that, you can bake the details of the high-poly model into normal maps for your low-poly model, which should give good results even when you've drastically reduced the number of vertices.
For mesh retopology, I found the LoopTools and F2 addons very valuable. They should come with Blender, you just need to activate them. F2 especially helps you fill in faces when you have surounding geometry that helps guide the fill in process; it works wonders on well-modelled quads and speeds up your retopology process. I'm doing retopology in two ways: Either "Top down", which means I'm surouding the target with very large blocks and then use the loop tools to progressively get closer to the high-poly mesh, or "bottom up", where I start modelling with a loop of single quads and then extrude to finally cover the whole model. Which way I go depends on the underlying geometry; if it's fairly simple, I found the top down approach was quicker.
Answer: i had models like that too before i was able to create my own projects... here's how i made most of them usable...
to connect the vertices, simply select the coplete object in edit mode. then hit OBJECT/VERTICES/REMOVE DOUBLE.
to reduce the size (# of vertices), switch to OBJECT MODE, go to MODIFIERS and select DECIMATE. there choose for UNSUBDIVIDE if the model is created mainly in quads. change the ITERATIONS value until the model still looks acceptable and hit APPLY.
if the model is created in tri's, choose for COLLAPSE and change the RATIO value (in OBJECT MODE) until the model still looks acceptable and hit APPLY.
hope this helps
Comment: welcome to the site. Instead of "shouting" the buttons and menu items in all caps, the preferred method is italics like this: *Object* > *Vertices* > *Remove Doubles*. More info in our [style guide](https://blender.meta.stackexchange.com/a/251/2217).


How can I highlight specific pieces of text within a blog post?

Question: I have searched for a simple method to allow a user to highlight a specific piece of text with a user chosen color but have not found one readily apparent. I have found a few methods related to syntax / code highlighting. I am not trying to highlight code but merely text within a blog post. Preferably I would like a simple method that provides a UI button within the editor itself as some users that post articles are not technically savvy and may have issues with short codes. I am currently running Wordpress version 3.5.1.
Comment: Have you looked at any of the numerous WordPress shortcodes plugins? Most have a TinyMCE editor interface.
Comment: Agreed with @helgatheviking Also, I think, but can't remember for sure, that CKEdit will highlight text in a way that might work for you.
Comment: Modified question to reflect simple method (which is what I actually need)
Comment: Ok. On topic now but how do you want this to work? You want people to be able to select text and choose it for highlighting in much the way you can choose text and bold it or italicize it?
Comment: CKEdit work well enough to satisfy my requirements. If @s_ha_dum can post as an answer will approve.
Answer: While I rarely recommend plugins, the CKEditor plugin will do highlighting of selected text. That sounds like exactly what you want. And it is a greatly enhanced editor relative to the default one. Short of creating your own editor buttons and supporting functions, that would be a pretty good choice.


BlackBerry user authentication with LDAP

Question: After I've tried so much and still being stuck, I hope anyone here has an idea. Well, that's the situation:
I'm trying to login to my app with ldap. If its possible to login there, you can go on using the app.
I've already tried to use net.rim.device.api.ldap.LDAPQuery but the problem is, that if I try to log in, the LDAP Login Screen overlays my Login Screen and I have to enter my username and password again. Besides, if I enter nonsene into that form or cancel the login I also get logged in.
By the way, why can't I set my password with LDAPQuery ? I just send my username to the directory. That's not what I feel about security.
Adding a 3rd party jar files to use LDAP was another negative attempt. I also couldn't get them preverified. And I think that's the main reason why they're not working.
Here are some information about my development environment:
I'm using eclipse with the BlackBerry java Plug-in and BlackBerry Java SDK 5.
Ok, if you have any ideas on that or which alternative library I could use, please let me know !
Answer: Is your device connected to a BES server (via MDS)?  From what I understand, the native LDAP client libraries in the BlackBerry API only work as an interface to a MDS (Mobile Data Service) LDAP component which does the actual work.
If not, then you'll need to find a third-party LDAP library that works on BlackBerry/J2ME.  I have seen this question asked before but have yet to hear about a third-party LDAP library.
Comment: afaik, our device isn't connected to a BES. Therefore I'm looking for a third-party lib. But I haven't seen one yet. Openldap and an self-written one are failing at preverifying.
Answer: From what I can tell the LDAPQuery class in the RIM API does not work.  Please let me know if this is incorrect.


Citing works in a list without having read them

Question: I know this may seem a duplicate question, but I haven't find an answer to my question and I am scared to ask my supervisor.
I am doing my literature review in sociolinguistics and I have different reputable sources: articles and books.
Most of the authors quote the same famous works while describing that they made a contribution to the discipline.
Many of these works are well known and not easy to find (old).
So, is it ok if I write "[...] These themes were examinated by other scholars (e.g. Smith 1970, Doe 1977)", without having read those two books by Smith and Doe, but having read reviews and studies that explain them?
I have just read a dissertation which was written in less than 1 year after fieldwork and it has hundreds or references: I can't imagine the author actually read it. It seems common to me.
Can somebody clarify?
Comment: How can you cite something to support, or not, your arguement without reading it?
Comment: Well, if I am reading studies that ALL mention the fact that Smith and Doe studied Italians in New York, I would say that it's OK if I say the same thing.
Obviously, if I go into details of the study, or I quote something, I must read it. But this is a mere list, just to give references.
Comment: To give you an example, this is from a thesis that was accepted in my university. The introduction of this thesis is all like this. I cannot believe that the author has read all the papers he cites and he wrote the thesis in one year, while also analyzing data etc.
Example: https://imgur.com/EsKUHMU
Answer: There are two answers that are not logically exclusive:

When you cite something, you should be reasonably certain that the source pertains to the situation and that you are representing its information accurately.
Many scholars cite materials they have not read closely, have read in parts, or that they have read through another source.

Usually, you need to read or at least consult a source in order to verify that your understanding of the source is correct.
For example, in my field (English), I read most texts I cite, since many texts are primary or archival sources that I interpret closely, or secondary sources that I engage with directly. I need a high level of understanding to respond to other scholars directly. However, there are some secondary sources that provide minor support to what I write. I skim, reading enough to understand the argument or to find the chapter or section I needed. I've never cited a source without at least looking at it.
In many STEM fields, the tendency is to cite more and with infrequent quotation. Especially in introductions or literature reviews, providing a representation of available knowledge is more important than responding to an individual author or argument. For many of these sources, the texts may have been read or skimmed, in whole or in part. For an article, they may only read the abstract and the results. How close they read those sources often depends on the level of specificity in their reference. Is it one of several works on a rat behavior, or are you indicating a specific result? At a minimum, I'd expect such authors to look at the source, even if they don't read in full.
In whatever field you're in, the presumption is that the cited fact or argument is accurate. So you are responsible for certifying that the information is accurate. If you use the source extensively, you should read it. If you use the source quickly, you should at least look at it and double-check its credibility, even if you don't read it in full. Don't rely on secondary summary alone. The Office of Research Integrity (a unit of HHS) has this advice in an article titled "Citing Sources that Were Not Read or Thoroughly Understood":

The reader should note, however, that there might be instances in which the practice of citing sources that were not read may be acceptable. For example, an author may simply wish to point out a well-known discovery or theory and provide the reader with the original citation. When this is done without misleading the reader into believing that the author read the paper detailing the discovery and is thoroughly acquainted with its contents, then no real harm is done. For example, in a paper on intelligence testing I may want to refer the reader to the psychometric properties of the X test and write: "for a review of validity of reliability of X test see reference Y". Although I am clearly aware that reference Y reviews validity and reliability for various intelligence tests, including test X, my citation of this work does not imply that I have read and processed its contents. I am merely aware that relevant material may be found in that reference and point the reader to it. However, if in a different paper I were to write that "Smith (1879) studied the effects of X on Y and concluded that X is as important as Z and both are critical causal variables in the incidence of Y" such a statement strongly suggests that my summary of the study is, in fact, based on my reading of that paper.

ORI rightly points out that whether and how closely you need to read it relates directly to whether I'm claiming an author addresses a general topic or whether I am specifying a result. If I'm doing the latter, I had better ensure with my own eyes that I've seen and understood that result. That is why they provide this general guideline:

GUIDELINE 18: Generally, when describing others' work, do not cite an original paper if you are only relying on a secondary summary of that paper. Doing so is a deceptive practice, reflects poor scholarly standards, and can lead to a flawed description of the work described.
Answer: You need to be able to stand behind the claims you are making, with reasonable certainty.
To what extent reading a source before citing it is necessary for this will vary, as will how detailed any such reading needs to be. What reasonable means will also depend on the context.
Examples:

If all you are claiming is that a particular source covers a particular topic, it takes very little effort to verify this. Checking the abstract would usually suffice. The risk in getting it wrong is small, so trusting other people on this doesn't seem too dangerous.
If the precise conditions of a mathematical theorem matters for whether or not it is applicable in your setting, you better double-check that the actual theorem says what you need it to say, rather than relying on an abstract, etc.
If you are weighing in on a philosophical debate, I would not trust a critic of a particular work to accurately depict the original authors views - reading the original (carefully) seems unavoidable here.

Citations typically serve three distinct purposes.
A citation can be there to substantiate your points, and to provide evidence for whatever you are saying. A mistake here can bring down an entire paper, and relying (purely) on an indirect source seems very risky here.
Citations are also the scientific currency. This means that citing a secondary source in place of a hard-to-verify original one is problematic, because it does not give proper credit. Here is where citing completely inaccessible works will show up occassionally.
Finally, (as in the example in the question) citations can be there to provide broader context. For these, a balance between taking effort to verify them, taking the literature consensus for granted, and simply not mentining them will be the way to go.
If in doubt, state that according to source X, in source Y the following happens.
There is no reason here not to have Y in your bibliography. Omitting it only makes it harder for your readers to track down Y, and it can deprive the authors of Y of a deserved citation.
Answer: The short answer to your question is no, you cannot cite works without having read them. But there is a solution:
The fact that you are reading multiple works that explain what Smith and Doe did in their research will work well enough for your literature review. If Source X and Source Y say that Smith and Doe did work on certain themes, then say "These themes were examined by Smith and Doe, as later scholars argue that they did Z" (Source X, Source Y), where Z is whatever Sources X and Y say.
While it is certainly better to read the original source material, a literature review can still be effective if you explain how you came to know what is in the original source material. Additionally, it is possible that Sources X and Y misrepresent what is in the original source material; if you cite the original with someone else's interpretation, there is a potential for many problems (both with scholarly knowledge and another with academic dishonesty).

Barring limitations like the destruction of sources, the inability to find "old" sources is usually not an acceptable excuse for not including them in a paper. There are many avenues to obtain hard to find sources, like InterLibrary Loan, for example, which should be a service you can use for free at your university. Ask a librarian if you need help.

I have just read a dissertation which was written in less than 1 year after fieldwork and it has hundreds or references: I can't imagine the author actually read it.

It is important to keep academic work honest. You would be surprised how much extra reading one does when they are passionate enough about a subject to write a dissertation on it, and besides, this is not a viable excuse for cutting corners.
Comment: No, it is not. But in that specific case, I checked the bibliography and there are at least 50 PhD thesis plus many other books and articles.
I don't think that a person can read all that material, write their dissertation and transcribing interviews and analyze them in just one year. I think he mentioned those dissertation in the literature review because they are well known in the field and quoted by others.
Comment: @Stef: Did the author provide any discussion about the purpose of the bibliography? I wrote my 220+ page Ph.D. thesis with 900+ references in about 6 months (the work mainly based on previous 6 months' research), and the last two sentences of my Ph.D. thesis abstract are: *We conclude with two historical chapters containing some refrences* [sic] *that do not seem to be generally known. An extensively annotated and cross-referenced bibliography of over 900 items related to our subject matter is provided.* ("do not seem to be generally known" was a huge understatement, by the way)
Comment: *(a few minutes later)* On the other hand, I don't think I actually **cited** any of the references that I had not at least seen firsthand. Indeed, I went to great lengths to obtain photocopies of virtually every one of my references (cited or not) since at the time I was in close proximity to 3 major university libraries, and I was fairly sure that in later years I would never again have the opportunity to get some of the papers (this being before the internet, whereby now most everything has been digitized). Also, I wanted to ensure accuracy in the titles, page numbers, etc.


How can I get a prompt for deleting index.lock file in magit?

Question: This is a long standing issue https://github.com/magit/magit/issues/2708 . I feel that a prompt for deleting the transient file would compensate in most cases. Is there a reliable way to achieve this? Thanks!
Answer: I have added the following to my .init.el file:
<code>(defun magit-remove-git-lock-file ()
  "Remove git's index lock file, if it exists."
  (interactive)
  (let ((base (magit-toplevel)))
    (delete-file (concat base "/.git/index.lock"))))
</code>
This gives me a function to resolve this condition when it occurs.
As a response to other statements made, please note that when this happens to me, there was no other process running git commands, and the lock file did indeed remain visible on-disk for many minutes, forcing me to delete it either manually or via this code snippet.
Comment: I'm using a similar command via `advice-add #'magit-refresh :before` . However I think a prompt would be better.
Answer:
Is there a reliable way to achieve this?

No. It is inherently risky to do this because what you are trying to accomplish is to run multiple things in parallel that cannot be run in parallel and the file you want to remove is the file whose purpose it is to prevent that from happening.
Also I don't know how that could be implemented.
Comment: From the linked issue, it sounds like the file wouldn't exist by the time you got the prompt anyway: "I have started checking to see if the file actually exists and have yet to find [an] instance when it does."


Android phone - logging into Pokemon Go account without adding the Google account to my phone

Question: I had a fairly good Pokemon Go account that I put a lot of time into. It was linked through one of my Google accounts. However I was having a lot of issues with other aspects of that Google account and didn't want it synced to my phone anymore. So I got rid of it and started a fresh Google account. Now though, when I try to log in to Pokemon Go, it wants me to add the Google account, and that's the only option for logging in. I really don't want it all re-synced to my phone, so how can I just log in by typing the email and password, and not adding the account back on to my phone? Or, can I link the email to a Trainer account, and then log in with a trainer id? There has to be a way around having that account back on my phone. I don't want to start a new game....
Comment: Please don't vandalize your post. I have rolled back your edit.
Comment: Since you resolved the issue, you can write in your own answer to help others who encounter the same issue.
Answer: They added the option to log in with Google account just to make the login easier. If you want to make a new account, you should make a Pokémon Trainer Club account. If you want to log in with another Google account, you need to log out and then log in with the second account. I don't believe that there's another method.
Comment: To clarify, it's not possible to log into Pokemon Go with a Google account that is not added to the phone.


What is high dimensional data in data mining?

Question: Currently I am studying effect of high dimensions of data on clustering , for experiment purpose I want to use kdd dataset  from UCI which contains 42 features.
Is kdd a high dimensional data or what is the threshold of number of dimensions beyond that we can say data is high dimensional ?
Comment: High dimensional, as indicated by the question, is subject to opinion. In my experience, in machine learning we consider anything less than thousands of dimensions low dimensional, but opinions will vary.
Comment: Yes , it may vary as per opinion. I am searching "Is there any strong reference (research paper ) which discuses this issue in detail?"
Comment: You need to look at stuff in your community and see how they define "high dimensionality". Then find the expected value of "high dimensionality" as you weight by the importance of the person who utters it. I dunno this dude, but he tests against high dimensionality by trying increasing dimensions from low (hundreds of dimensions) up to 13k dimensions (which they consider high dimensional) http://togaware.com/papers/ijdwm2012.pdf
Comment: The question "what is high-dimensional" is discussed tangentially in this thread, but I don't think it's a duplicate question. Just also of interest: http://stats.stackexchange.com/questions/99171/why-is-euclidean-distance-not-a-good-metric-in-high-dimensions/99191#99191
Answer: A way to see high dimension, is when there are more regressors/predictors than observations. If $p$ denotes the number of regressors and $n$ the number of observations, high dimension is when $p > n$ and even $p >> n$. If I remember well, penalized regressions (ridge, lasso) have been introduced partly in order to tackle this issue (classical OLS in this setting to do not give a unique solution).
Edit :
As asked, some details about what I said. And I apologize about the fact that what I'm talking about is more relevant in a supervised framework.
This definition (which can be thought as subjective of course) is the consequence of the following. If you consider a classical linear regression : $Y = X\beta + \epsilon$ then you have the OLS estimator : $\hat\beta = (X'X)^{-1}X'Y$ which is valid only if $(X'X)^{-1}$ exists. Or if $dim(X)=(n,p)$ with $n < p$ then $X'X$ is not full rank, then cannot be inverted and then no more $\hat\beta$ as previously.
So switching from $n>p$ to $p > n$ is not trivial. Or multiple linear regression is widely used (especially in econometrics for instance, but also in epidemiology when studying genes...) hence I think it is a convenient way to define "high dimension" (but that's true : it's subjective) because you need to do something different from what you usually do.
For clustering, maybe it can be seen differently, with k-nearest neighbors curse of dimensionality is reached a long time before $p > n$...
Some references :

http://statweb.stanford.edu/~tibs/ElemStatLearn/ The Elements of Statistical Learning where you can find such a definition and a lot of other things
for an econometrics perspective, for instance this presentation : http://www.nber.org/econometrics_minicourse_2013/Chernozhukov.pdf or this paper http://arxiv.org/pdf/1105.2454v4.pdf High dimension problems is a very dynamic field of econometrics at the moment.
Comment: Can you explain why this definition is more helpful than others? If it's subjective, then can you cite things that shows the kind of community that follow this definition?


Why is having shields in AoS 'optional'?

Question: There are some units in Age of Sigmar, Skaven Stormvermin for example, that says that "some units cary shields into battle." The units ability to carry a shield is not restricted by any weapon combos or special abilities, and the shield gives a flat +1 bonus to save rolls when the unit is equipped with them. So what reason would you 'not' equip shields to the unit since it is just better? Is it only because of the physical models that may or may not have shields on them, or something else I missed?
Answer: Age of Sigmar is very much designed with the "beer and pretzels" mindset. The main reason is that you may have a bunch of models without shields. If your opponent doesn't care, you can always say that all the models have shields.
Comment: Link to Wikipedia added. Basically fairly light gameplay, strong on theme.
Comment: Makes okay sense to me. Could you explain what the "beer and pretzels" mindset is?


What are the EU-equivalent terms of the FAA ATC tower, TRACON, and center in radio calls?

Question: Does ATC in the EU have equivalents to the US FAA tower, TRACON, and center facilities? What are they called?
Comment: This is too broad @jeff0000.
Comment: [Related](https://aviation.stackexchange.com/q/19365/62), but as you can see from that question (and others linked to it) this is probably a very broad question. If you're asking about the specific equivalents of Tower, Approach and Center then you might re-word your question to focus on that.
Answer: Area control centre   CONTROL
Approach control    APPROACH
Approach control radar arrivals ARRIVAL
Approach control radar departures   DEPARTURE
Aerodrome control   TOWER
Surface movement control     GROUND
Radar (in general)  RADAR
Precision approach radar   PRECISION
Direction- finding station HOMER
Flight information service INFORMATION
Clearance delivery DELIVERY
Apron service APRON
Company dispatch DISPATCH
Aeronautical station RADIO
Aerodrome Flight Information Service AFIS
Heliport Information Service HIS


How do I get more pet chests in Fallout Shelter?

Question: I have Fallout Shelter on two devices- PC and phone. At some point on both of these devices I received a free kind of Lunchbox which gave me one pet. This was before I got 13 people in my Vault. No matter how many game files I start, I have only ever received one on each device. How does this work? What are my chances, if any, of getting a second?
Answer: The Fallout Shelter save games are not particularly robust against editing.  It is actually JSON formatted.
You can also just edit in more Pet Carriers using Fallout Shelter Save Editor
Comment: Thank you. I will be sure to hack *cough* USE the tool you have recommended.
Answer: The only ways to get the pet carriers are limited.

You get one(as mentioned in the question) from a lunchbox
Missions, it is possible to get lunchboxes, Mr. Handies, and, yes, Pet Carriers
And, of course, buying the pet carries


Basic questions about running Mathematica

Question:
Is there a command window and an editor in Mathematica 8 similar to
those in Matlab? In Mathematica GUI mode, all I saw is write code and run it in the same
notebook.
In my Ubuntu terminal, I successfully started Mathematica by ./math (which is the only way I know by the way and I would also like to know what options are available when starting up).
When
I simply copy and paste the code from Heike , nothing new
appears, and when I copy and paste the code of Daniel, it
works. Wonder why?
Is it correct that there are exactly two ways of running Mathematica
code: in a notebook, and in a Mathematica session running in my
Linux terminal?
Are the notebook way and the GUI mode the same thing?
What does "kernel" mean in Mathematica?
What are some basic concepts and common sense of running Mathematica?
Comment: You might want to start reading some documentation in the built-in help system or it's online mirror. [This](http://reference.wolfram.com/mathematica/tutorial/RunningMathematicaOverview.html) is a good start in this case.
Comment: http://mathematica.stackexchange.com/a/259/73
Answer: Heike's code produces a graphics output. So if you run it inside a raw kernel (which is what the math command does on linux), it won't display any graphics. Instead you'll see something like --Graphics-- on your screen. To actually display the output, you'll need to load the JavaGraphics package as <<JavaGraphics` before the plot command (this needs to be done only once per session).
Jens has more on running Mathematica without a front-end. Brett Champion also notes the following:

When using JavaGraphics`, graphics are rendered by a child front end and converted to a bitmap format. So most new features of graphics are supported. The exception is that if there are interactive aspects to the graphic (tooltips, mouse-overs, Dynamics), they will effectively be ignored. Visualization functions sometimes have problems since in order for them to work correctly, they have to handle Show and DisplayFunction just right. If you do run across problems with a visualization function when using JavaGraphics` , please file it as a bug.

As for the rest of the questions, I'll refer you to the official documentation that Sjoerd shared, as there is no need to duplicate information.
Comment: That warning is not accurate.  When using ``JavaGraphics` `` graphics are rendered by a child front end and converted to a bitmap format.  So most new features of graphics are supported.  The exception is that if there are interactive aspects to the graphic (tooltips, mouse-overs, `Dynamic`s), they will effectively be ignored.  Visualization functions sometimes have problems since in order for them to work correctly, they have to handle `Show` and `DisplayFunction` just right.  If you do run across problems with a visualization function when using ``JavaGraphics` ``, *please* file it as a bug.
Comment: I think if one needs to work with the terminal, to see graphics one could `Export` them to png and use any image viewer.
Comment: @R.M Thanks for pointing out that `JavaGraphics\`` now supports all version 8 graphics. I must have tested it on version 7 when I saw that there were missing features. I've changed my statement on the web page you linked.
Comment: @Jens Brett deserves the credit for that (I think it was also discussed in chat by a few people). My apologies — I should've pinged you to let you know that it has changed :)
Answer: When you see Mathematica for the first time you try to fit it into the mental model of how software works. While doing that, one of the first things people do is to try to classify Mathematica as a GUI program or as a command line program. Mathematica is unique in that it is both at the same time. For example, commands can take graphics as arguments.
Mathematica has two separate components: The Kernel and the Front End. When you run Mathematica inside a terminal window you are only running the kernel. The kernel let's you do any calculation but you will be lacking the interactive features.
Comment: Thanks! Isn't Matlab the same way as you described?
Comment: @Tim, Mathematica does not have a MATLAB like GUI, with windows showing files in the current directory or local variables. Most of the stuff, like plotting, happens inside the notebook, and not in separate windows like in MATLAB.
Comment: @Tim does Matlab allow you to copy and paste a graphic directly into a function as an argument?
Comment: @Mr.Wizard: I think every graph in matlab has a handle, so it is possible to process that handle. Is it?
Comment: @Tim sorry, I don't use Matlab; I was curious myself.
Comment: @Adal: You can have variables local to your Notebook by using "Evaluation → Notebook's Default Context → Unique to this Notebook" from the Notebook's menu.
Comment: @celtschk: I was talking about the little Workspace window that Matlab uses to show you the current variables: http://www.hec.nasa.gov/news/gallery_images/matlabdesktop_lg.jpg
Comment: @Adal: OK, I've never worked with Matlab, so I didn't know that. I misunderstood what you were saying.
Answer: You can start a standalone kernel which pretty much behaves like a very rudimentary command line window. The normal FrontEnd (the "notebook interface") is an extra program which basically is the standard editor but also allows to send pieces of code to an (or several) connected kernels. For the communication these two programs actually don't use the command line interface you see when starting a standalone kernel but a more structured protocol called MathLink.
A notebook file opened in the FrontEnd (= the notebook interface) behaves very similar to a matlab script file with cell mode enabled, where you also can send the code within a "cell" to the kernel. The main difference is that the output will be shown in the command line window (and needs to be saved in an extra file if you want to keep it) in matlab but will be shown in the notebook right below the evaluated cell in Mathematica and become part of that notebook file. Another big difference is that the Mathematica FrontEnd is really a standalone program and you can quit the kernel and start another one from within the FrontEnd, whereas to restart the "matlab kernel" you'll need to restart the matlab graphical user interface.
Especially when you edit .m-package files (not the .nb-notebook files) with the frontend what it does technically is very similar to the matlab editor: in both cases there is some "markup" code inserted into the text file which the editor uses to structure and format the text to show. The notebook file format is somewhat more involved and has AFAIK no real counterpart in matlab, what probably comes closest (but not really) are the matlab "notebook files" which can be used to prepare your matlab code for publishing with html- and latex-formatted comments, but a Mathematica notebook is like a WYSIWYG version of that which will additionally allows for interactive content (see Manipulate and Dynamic).
By using the comand line interface or the mathlink protocol (along with some of the higher level variants like JLink or NETLink) there are in fact infinitely many possibilities to run Mathematica code, there is e.g. a Mathematica mode for emacs or webMathematica, which lets you embedded Mathematica code in html to be executed on a webserver. If you are looking for an interface that is more like what you are used to from matlab you could also have a look at Wolfram Workbench, which is basically a Mathematica plugin for the eclipse IDE.
But I think especially for a beginner it is much better to get familiar with the normal notebook interface, otherwise you'll stumble across peculiarites like the graphics output every now and then. Just because the notebook interface is different from what you have seen before doesn't mean it's bad: in fact I think that for a great many use cases the concept of the notebook interface has big advantages and only by making use of these you'll get the most out of Mathematica's possibilities. If you don't engage in the "Mathematica way" and use it just like matlab with a different syntax you can't expect to gain very much except of wondering about oddities.
A different interface (like the workbench or the command line interface) only seems to make sense when you have very special demands, e.g. you are writing more involved packages for others to use or you need to run large jobs using a job queuing/scheduling system.


Are 3h 58m enough time to transfer flights in Atlanta (from Colombia to Germany)?

Question: I'm flying from Colombia to Munich with transfer in Atlanta. The transit time is 3h and 58m. The flight is on Sunday and Atlanta, indeed, is the airport with the heaviest passenger transit in the world. Is it reasonable to think that I will have sufficient time to change flights? Am I in high risk of losing the flight? Bear in mind that I will have to pass immigration with a tourist Visa (last time at JFK, I spent almost 2 hours doing the immigration row). I don't know the airport or if I will have to change terminals.
Comment: What airline(s) are you flying? Barring a terrible experience in immigration, 4 hours should be plenty of time to transfer.
Comment: Usually the international arrivals and departures will be in the same terminal. There is an International Terminal at ATL. If you were flying to somewhere in the US you would be more likely to change terminals, but Colombia to Germany probably will be in the same terminal.
Comment: You should also be able to look up the same flights from today's schedule and see what gates they used to get a better idea. Try a flight tracker website or phone app.
Comment: @NadjaCS international - International connections in US also require you to pass through immigration on arrival
Comment: @Akash - Yes indeed. But there was also a question about changing terminals. Immigration is going to be accessible from the international terminal. The international arrival and departure will most likely both be in the international terminal, but this can be confirmed by looking at past instances of the same flights.
Comment: @MatthewHerbst It doesn't really matter. Getting between terminals at ATL is very fast.
Comment: @NadjaCS Getting between terminals at ATL is very fast so, even if the asker needed to do that, it wouldn't matter.
Answer: Atlanta is a very efficient airport.
They have a large immigration and customs area, which moves passengers through expeditiously. If your bags are checked through to Munich, then you simply drop that at recheck just outside customs, clear security and head to your gate.
If you are flying on different tickets or airlines, then you may have to recheck your bags.  The International check in is just outside F concourse, so doesn't take too long to reach it for check in.
All concourses are interconnected by a train which runs every five minutes or so.  But most International flights depart from E & F concourses which is where you will likely arrive.
4 hours should be ample plenty.


Prevent getting destroyed in the middle of time travel

Question: In H.G. Wells' The Time Machine, the time traveler uses an open-air time machine that does not immediately teleport through time, but rather speeds up time for the person inside the time machine. So, let's say that while time traveling, the Time Traveler, unfortunately, gets struck by something, which is very likely considering that to someone not riding the machine, the machine is going very slowly through time, making it easy to hit. Is is plausible to design a time machine such that it splices the rider off into a separate small universe bubble and re-inserts them back into the original universe, to prevent disasters like this from happening?
Comment: If you have time travel already, then why not?
Comment: You know, the upside down question to this might be very popular... I'm traveling through time, which means this frozen "me" in a machine is sitting there day after day.  Nobody can hurt me, the time distortion caused by the machine won't allow it, and I can't be moved (same problem).  What would people do?  Build around me?  Graffiti me?  I'd take it to the Sandbox to make sure it's right or it might be too primarily opinion-based.
Comment: You know, H.G. Wells' time machine was an early model that had its weaknesses (which probably was the cause of character's demise). Most of the later models (ex. "Back to the Future" machine) are indeed traveling in a kind of its own "time bubble". However, many other issues still exist, but rest assured, best sci-fi minds are keep working on this.
Answer: There is an argument to be made that this 'bubble' is a natural side effect of time travel already.
Your open air time machine is speeding through time, but not space (we'll just hand-wave the implications of this for now as it's out of scope of this question) but the rest of the surrounding environment is not. That means that there has to be some form of localised field, or boundary, inside which the time field is in effect, outside of which it isn't.
When you think about it, this has to be the case if anyone is going to survive. After all, if it was just you and the time machine, it would make it a lot harder to breathe if the oxygen molecules entering your nose end up 3 months in the past before they reach your lungs.
So let's assume a boundary exists. The next question to ask is whether or not things can permeate that boundary. I'm going to say no, because the boundary presents a lot of issues for relativity in particular. What we're describing is in essence someone travelling at the speed of light (or faster) while standing still.
In this case, one of two things are likely to happen;
1) The field boundary would appear from the outside to be a perfectly black, solid sphere, because light would not be escaping it or bouncing off it.
2) The field would cause a devastating shockwave through time that would wipe out anything in relative (no pun intended) proximity through the entire body of time through which it travels.
Either way, I wouldn't be touching it. I wouldn't be going anywhere near it, and I certainly wouldn't be throwing anything at it.
So, even if it was proven by someone that the time field boundary was permeable, this increasingly hypothetical someone would not be me. Certainly not by direct experimentation at least.


Undefined Language versions appearing on Sitecore Items

Question: The Language 'Danish:dansk' exist with version on certain items but it is not added/defined under System(Sitecore/System/Languages/).
How is this Language added and how can I resolve/restrict such kind of issues?
Answer: The language version is probably there by the default installation of Sitecore. They add a few language versions by default, even though the language itself is not listed under /sitecore/system/languages.
If you have Sitecore Powershell Extensions installed, you can remove the language with the following command:
Remove-ItemLanguage -Path master:\content\home -Language "da" -Recurse

This will remove all da versions under /sitecore/content/home. Adjust path or language (e.g. da-DK) if necessary.
Comment: I want the defined Languages(/sitecore/system/languages) to be used only and restrict such kind of issues from happening again and again.How can I do so?
Comment: Well, AFAIK, you don't, they are just there. I installed a Sitecore v8.1 a while ago and also had to remove multiple undefined languages. Next to Danish I also had Japanese and German I think. Once they are removed, they will not be added again. Unless you install old packages or revert serialized items.
Comment: I guess you removed the multiple undefined languages by removing it from the "LanguageDefinitions.config".
Comment: No, I didn't touch that file. I'm not sure when or how Sitecore uses this config file.
Answer: I have fixed this issue. Like Thomas suggested, use PowerShell command Remove-ItemLanguage -Path "master:\content\companion" -Language "da" -Recurse to delete language content from item(s) and sync (I'm using Unicorn sync). It will disappear from available languages list in content tab and will never appear again.
The Language Danish:dansk exist with version for item(s) because it would have been deleted from /sitecore/system/Languages but not from item(s). If you delete language from /sitecore/system/Languages, it would not delete related content.
Although there is a setting:
<setting name="Languages.AutoRemoveItemData" value="true" />

to configure it. It seems it is a known bug in Sitecore.
Answer: The language da is available when Sitecore is installed. By default, when Sitecore installs, 4 languages are available in the Language Version as provided in the screenshot below:

Note that this is a fresh Sitecore installation. Moreover, if you have created the language version from the option "More Languages", it will not appear directly in the sitecore/System/Languages. You will need to manually create it. This is why it is not appearing in the languages container.
So, in order for you to set the Read/Write access on the language, you will need to create the language da by right click on the Languages container -> Insert -> Language. Then, select the Danish language from the dropdown:

and click on next to continue the wizard. Note that once you selected the language, it will already prefill the textboxes. No need to add anything in there.
Answer: This is restricted by default. To control what languages your editors can use, you do this by restricting read-access for the items under the Languages node you show in your picture.
Administrator users will be able to add any language versions to your items.
The example you picture is part of Sitecore's default installation. Out-of-the-box. It is not an indication that anything in your setup is wrong.
Comment: No. But as mentioned; this comes out of the box. Admin users can add any language version to any item - regardless of what has been set up under ../languages. This is by design.
Comment: Out of the 3 Languages(en-au, en, da) 'da(dansk)' is not expected and it is not even added under the Languages(/sitecore/system/languages) in Sitecore. As I know the Language read/write access option can be provided to the languages existing or added under '/sitecore/System/Languages'. As 'da' was not added under 'System' and the administrator is also not provided with the 'More Languages' button option(on click of Language button) to select any languages, I am wondering how it appeared and how I can restrict such kind of issues.
Comment: My motive here is only the required Languages defined for my website (/sitecore/system/languages) should exist with a version.
Comment: any suggestion on how to restrict such kind of issues? I guess you understand and agree on the issue that any Lang like 'da' not defined and coming up in the website with version is not accepted.