What mechanisms prevent a process from taking over the processor forever?

Question: Suppose a process keeps running code (e.g. an infinite loop). How can other programs take over? What prevents the process from remaining active forever?
Comment: Hello! The question appears poorly worded and off topic for this site!
Comment: In the processor itself, probably none. The operating system sets up things so that a clock interrupts whatever is happening periodically and the operating system gets control.
Answer: Various peripherals are connected to the main processor. When an event happens in a peripheral, the peripheral sets an electric signal which causes the processor to take some action. The act of setting this signal is called an interrupt request (IRQ for short), and the aftermath of the interrupt request on the processor is called an interrupt.
When a processor receives an interrupt, it typically does something like this:

Mask interrupts. This means that if other IRQs happen (coming from the same peripheral or a different one), they won't be noticed just yet: they will not have any effect on the processor until interrupts are unmasked.
Save the value of the program counter register to a register dedicated to that effect. Also save the value of a register that contains the processor mode (e.g. user mode, kernel mode, interrupt mode, …). Depending on the processor architecture, other registers may be saved as well (e.g. stack pointer).
Switch the processor mode to interrupt mode.
Read a value from a predefined address in memory, or from a register. This value is called the interrupt vector.
Jump to the address given by the interrupt vector.

The code at that address is typically kernel code. On computer architectures with memory access permissions, the kernel normally prevents unprivileged processes from setting interrupt vectors or from changing the code at that address. The kernel code typically begins by copying the saved register values into memory, so that they won't be forgotten if some other interrupt occurs.
One of the peripherals that can send interrupts is the clock. To avoid a process running forever, whenever the operating system kernel allows a process to execute (by branching to its code), it first programs the clock to send an interrupt at a certain time in the future, allowing the program to run uninterrupted only for a time slice.
If the process is still running at the end of the time slice, the clock interrupt occurs. The code at the interrupt vector is kernel code, so the process is no longer running: it has been preempted. The process's code and data are still around: the kernel can later decide to let the process execute some more by restoring the saved register values (finishing with the program counter).
After the kernel has finished its basic interrupt processing, and has performed whatever tasks it deems useful, it decides which process to execute next. This decision is called scheduling.
Some operating systems (mostly on tiny embedded systems) allow processes to run as long as they like. This is known as cooperative multitasking. (And some operating systems are even more basic: they only allow a single task at a time.)
Comment: This is an extremely amazing answer. Very well structured, and helped me relate to all the stuff that they teach us in computer engineering.
Answer: The technique is called preemptive multi tasking. See for example this Wikipedia article.
Basically the operating system runs every process for a short time, then suspends it and continues with the next process.
Comment: i am much obliged, I could not get any information about that. This will help me However , What mechanisms in the OS are used to supervise processes ?
Comment: The CPU has built in mechanisms that wake up the OS every now and then. Then the OS decides which process to run.
Comment: Thank you for getting back to me and thank you for helping me


What was the most common hard liquor of the Late Middle Ages?

Question: Is it possible to know what was the most common hard liquor of the Late Middle Ages?
I am not asking for the strongest drink in the Middle Ages, but which hard liquor was the most common during the Late Medieval Period.
Comment: There is an answer of on Reddit that might satisfy you: https://www.reddit.com/r/AskHistorians/comments/y15po/was_there_hard_liquor_in_the_middle_ages/
Comment: Also, I re-read your question and you ask "is it possible to know" and or course it's possible to know. If I go by Google then the answer is Brandy, but there was also a lot of whiskey. This one needs a deep dive that I can't give with some real book research.
Answer: I finally did a little digging. The Late Medieval Period is generally considered from 1300-1500. Whisky, did not become wide spread until the 1700s. The first recorded instance of Whisky production was in 1494:

The Guild of Barber Surgeons.[15] The earliest Irish mention of whisky comes from the seventeenth-century Annals of Clonmacnoise, which attributes the death of a chieftain in 1405 to "taking a surfeit of aqua vitae" at Christmas.[16] In Scotland, the first evidence of whisky production comes from an entry in the Exchequer Rolls for 1494 where malt is sent "To Friar John Cor, by order of the king, to make aquavitae", enough to make about 500 bottles.

There is ample evidence that liquor distilled from grapes and other fermented fruit well before the 1300's and Brandy was widespread by 1500. Neither Brandy or Whisky was drunk as much as wine or beer during this period, but just from the time line it looks like Brandy was a) easier to make since you start with wine and no cooking involved until distillation b) had a several hundred year head start on Whisky.
There were distilled beverages in Asia, but again not as widespread as Brandy in Europe.
Just based on the fact that the first mention of Whisky production isn't until 1494, only 6 years before the end of the Late Medieval Period and Brandy production is mentioned many times in The History and Taxonomy of Distilled Spirits before 1500, I think we can safely assume that Brandy was the most widespread distilled beverage in this time frame.
Answer: I would imagine it would be either whiskey or wine brandy came from Brandywine (excuse spelling or similar pronunciation) meaning burnt wine also cider was probably popular due to the fact that the water quality was poor
Comment: References for your claims would be beneficial.
Answer: What was the most common hard liquor of the Late Middle Ages?
When were the Middle Ages?

In the history of Europe, the Middle Ages or Medieval Period lasted from the 5th to the late 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance and the Age of Discovery. The Middle Ages is the middle period of the three traditional divisions of Western history: classical antiquity, the medieval period, and the modern period. The medieval period is itself subdivided into the Early, High, and Late Middle Ages.

The distillation process was little known and used in Europe during the Middle Ages. Wine was was distilled into brandy as early as 1313 but it was prepared only as a medicine and was considered as possessing such marvelous strengthening and sanitary powers that the physicians named it "the water of life," (l'eau de vie) a name it still retains.
The Late Medieval Period is generally considered from 1300-1500.

The first years of the 14th century were marked by famines, culminating in the Great Famine of 1315–17. The causes of the Great Famine included the slow transition from the Medieval Warm Period to the Little Ice Age, which left the population vulnerable when bad weather caused crop failures
These troubles were followed in 1347 by the Black Death, a pandemic that spread throughout Europe during the following three years. The death toll was probably about 35 million people in Europe, about one-third of the population. Towns were especially hard-hit because of their crowded conditions. - Late Middle Ages

Thus bringing everything into perspective, it is easy to see how distilled wine (brandy) would naturally have been used as a medicine back in the day, rather than an outright popular drink.

Brandy began to be distilled in France circa 1313, but it was prepared only as a medicine and was considered as possessing such marvelous strengthening and sanitary powers that the physicians named it "the water of life," (l'eau de vie) a name it still retains.
In the young America Colonies, George Washington began commercial distilling in 1797 at the urging of his Scottish farm manager, James Anderson, who had experience distilling grain in Scotland. With this experienced help, Washington became one of the largest distillers in young America with five copper stills operating 12 months a year. However, a few years earlier, Laird's America had opened (making it the oldest apple brandy producer) and began distilling applejack and brandy in 1780. The abundance of naturally available fruits for processing as compared to the labor-intensive planting and harvesting of grains resulted in young America's practical adaptation of the readily available harvest of local fruits.

The first recorded account for whiskey was in 1495. Certainly, it had been around before then.
It seems logical to presume that brandy was the most common hard liquor in the Late Middle Ages. It was in any case more widespread throughout Europe during this time frame.
Answer: It would depend on the crop the region had plenty of. Corn and rye would lean towards bourbon and wheat and potatoes towards vodka but it's all shine in the end.
Comment: I don't think corn and potatoes were known in Europe in the late middle ages, so I doubt they were producing alcohol from them.
Answer: It depends on the region. Most produced ales at the time were barley wines and meads, all reaching anywhere from 7% to 12% ABV. (Roughly, I am not an academic in this by any means.) As for liquor, I don't think liquors came around until later.


Does gasoline ruin an air filter?

Question: The carburetor on my 2005 Honda Shadow Aero (VT750C) had a bad leak and flooded the air cleaner assembly with gasoline.  The air filter was completely soaked with gas, so I let it air dry.  Is my filter ruined, or is it okay now that it's dry?
Comment: I should have read closer. This is why I leave stupid comments instead of really stupid answers sometimes :-) thanks for clarifying.
Comment: @Paulster2 It's a motorcycle. Though not too long ago they're putting fuel injection on motorcycles too.
Comment: Carburetor on a 2005 Honda? How's that? I wouldn't think they'd be using one on cars now for many years ...
Answer: If it was just a normal paper filter it is fine. If it is a re-usable washable filter then then I would suggest a wash and oiling procedure according to the manufacturer instructions.
Answer: The last vehicle in the USA to use a carb was the Susuki Jimmy in 1993. Your air filter element is bonded together with petro-chemical adhesives, and a lot of filters have a petro-chemical treatment to enhance thier performance. Soaking the filter in petrol can only be detrimental to the filter. Your best bet is to change the filter to avoid any possibility of it breaking pieces off and causing problems in the manifold or throttle body.
Comment: This is not necessarily true at all. For starters, the Kawasaki Ninja 500 was produced all the way through 2009, and uses a carb, like many other *motorcycles*. The air filters on most of these bikes, similarly, are to be coated in motor oil (a petro-chemical) upon installation.
Comment: The Honda Aero in Europe is an estate car, which I literally took it to be, most people would understand vehicle to be a car or truck. As far as it goes for motor cycles the hydro-carbon emmissions could be as high as 90 times that of an SUV, but since 2010 the emmissions standards have become increaseingly more stringent. This means that an oil soaked air filter would not be used on late models as it would draw hydro-carbons (the oil) into the engine and allow those emmissions.
Answer: I think you must have to mention it on bike Because carburetor is being used in them mostly and if its leaked than you must first air dry the filter after oiling procedure and then check it out by putting it back. But it would be better to replace it.
Comment: Dent - welcome to Mechanics.SE. This may just be a language issue, but your post doesn't appear to answer the question. Can you clarify.

Does gasoline ruin an air filter?


Archive block for nodes using Views

Question: How can I create an archive block like this, only for Drupal 7 (views 3)
http://chrisshattuck.com/blog/how-create-monthly-archive-block-drupal-blog-views
Answer: I think you can use the "Contextual Filter" for this. Choose the "Content: Created date" as the contextual filter. Then in the filter settings, choose "Display a summary" and save the view. Maybe this helps you to start with this.
Answer: I found this through searching. So for the completeness of the thread, here is a full tutorial covering how to create an archive block om Drupal 7: http://www.webbykat.com/2012/02/creating-monthly-archive-block-drupal-7-views
Answer: These are all fine and correct answers but fail to address the need for a Year to Month drill down. A client has a Views Accordion archive which has months as the top level. It has been difficult to turn this archive into one which nests the months inside of a specific year, such that the accordion shows years as the top level, and subsequently has each month of the year nested inside. There are a few template based solutions out there but none that seem to work with an accordion UI. Contextual filters don't seem able to handle this scenario.

Archive block for nodes using Views


Can you decode aes by hand if you have the key?

Question: I made a javascript aes encryption program and I do have the key to what I encrypted. Is there a way to use that key and figure out what was encrpyted without help of a program? I encrypted "Hello" with the key 2892 and got EQ/9Yt/IvIAmtF0wKYbb3+XYUOKuKlxJ. Is there a way to apply the key to the characters and fully decode what it says without making a program to do it for me? This is just so I can practice and yes I do know that I already have the text.
Comment: "Hello" isn't 128 bits. 2892 isn't 128, 192, or 256 bits. AES is only defined for block sizes of 128 bits, and for key sizes of 128, 192, or 256 bits. Whatever you used, it wasn't (just) AES. It may have been a mode of operation using AES, but it definitely wasn't pure AES. Not that anyone encrypts anything without a mode of operation, that'd be silly, but you have to know which mode was used to decrypt.
Answer: It would take you a while, but yes.  You'd have to print out several tables that calculate things for you like $GF(256)$ field multiplication and inversion, but you could do it.  It would be slow and tedious for sure, but doable.
Comment: Instead of inversion you'd just print the S-box. Also, probably even glued with multiplications by 1, 2, 3. The rest is arranging things rightly and xoring (with subkeys too). Writing things in hex could help, so that xoring is only a 16x16 table (which can be easily learnt).
Comment: Well, you don't *have* to print them out...
Answer: The easiest way to look "under the hood" of AES is likely one of the many AES in Excel spreadsheets that are floating around: https://www.nayuki.io/page/aes-cipher-internals-in-excel
You will also need to sort out how the initial message was padded because the AES block size is 128-bits, and "Hello" is not 128-bits.  There is a value to going through the s-box mathematics and the flow, but I would not suggest that anyone do the cipher completely by hand.
Comment: FYI, The base article goes long before that http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.107.5405 The site to download may require WebArchive.
Comment: @kelalaka I will if I get a few moments free.  Too many external pressures recently.
Comment: @kelalaka ooh, good link
Comment: You can write a better answer with that; The first educative try to ..... Hand calculations are error-prone... Using Excel will help you follow the calculations... And some extract from the abstract would be nice, too ( if the aim was understanding, etc.. ).
Answer: It would be very long (if it is even feasible) given that it continues at least ten rounds.
If you want to do something manageable, you can practice with the simplified aes, which is made precisely for practicing by hand tasks. It continues only two rounds and reduced parameters.
If you want to decode the real AES, my advice is to try to do one round of it and see if it is manageable with its real parameters.
Comment: Please add some content to answer the actual question: Is it possible to decrypt aes by hand? Otherwise, this should be a comment, not an answer
Answer: As others have said, yes, you can do it by hand.
I'm not aware of any task a conventional (ie not quantic) computer can do and you cannot. However, it could be that some tasks they can perform in one second would take a human an entire life.
Also, as pointed in one comment, what you have here is not "pure" AES. AES takes 128 bits blocks, and keys of varied size (64, 128, 256).
Your input, assuming UTF-8 encoding, would be 32 bits long (and usually would be padded), your key assuming UTF-8 is also 32 bits long (could also have been using as 16 bits integer). And your output is 32 "characters", which assuming UTF-8 is 256 bits. Your output, very surprisingly, is also entirely made of "printable characters" (letters, symbols and digits). It is very unlikely that AES would have such an output (except maybe some of the bad modes that are to be avoided). I thus highly suspect your output is encoded using... something... It "looks like" Base64 (it is compatible with its default charset), except it's too long to encode 128 bits.
Conclusion: yes it can be done, but don't try comparing what you'd do by hand with what you have here. Here, some extra processing has been done.


ASP.NET MVC with DDD architecture

Question: I am trying to understand Asp.Net MVC with DDD following is the structure of application according to the http://aspnetdesignpatterns.codeplex.com/

Application Layers
Presentation Layer   => MVC views,
Controllers(MVC)     => MVC
  Controllers class,
Cached Service       => ?,
Application Service  => ?,
Domain Model         => ?,
Repository           => repository
  class to interact with DB,
Infrastructure       => Class for
  logging, mailing etc.

here m having confusion in Application service and domain model,
where should i fit my business logic (in service or in domain model)
what exactly should be in service and what should be in domain.
e.g
suppose i want to add customer in DB
how should be the flow..?
as i know,
in controller class i will write like
var customeService = new CustomeService (_customerRepository);
customeService.Add(customer);

if m wrong please correct me here..
_customerRepository goes in repository
what goes in model and what should be the flow of code.
please clear me.
thanks in advance.
Answer: Eric Evan's book is the best place to start DDD as mentioned by @Arnis. Domain Driven Design Quickly is a short, quick-readable summary and introduction to the fundamentals of DDD.
what goes in model and what should be the flow of code.

Please check the following answer from @calebboyd to get an idea of DDD flows.
And about MVC, you can separate the controller from your presentation layers(views). But are you using this controller actions in different projects? If answer is no, my opinion is to keep it in one project.
Answer: Have You read this book? Start with that.
Term Service is overloaded.
Domain services encapsulates small part of domain logic that does not fit naturally in any of domain object (some say it's a sign that there's unidentified aggregate root in Your domain).
Application services contains zero domain logic. They coordinate domain.
Infrastructure services seems to me quite self-explanatory. Those contain technical details.

ASP.NET MVC with DDD architecture


difference between 'fast' and 'quick'

Question: I was reading a game of thrones and got an ambiguous understanding of two words: fast and quick
It looks like the author is describing two characters whose characteristics are quite opposite.
Is there any subtle difference?
Comment: http://english.stackexchange.com/questions/78110/the-difference-between-fast-quick-rapid   See my comment under tchrist's answer.
Comment: http://ell.stackexchange.com/questions/19096/fast-and-quickly-adverbs
Answer: It is difficult to differentiate these two words. I think it helps a bit to say "fast" refers to movement, "quick" to reaction. But a lot of uses are idiomatic and a matter
of the dictionary. A clean differentiation of "fast" and "quick" is not possible as there is an overlapping area.
The matter is complicated as "fast" has two meanings, it can refer to speed and it can express firmness. Dictionaries should have two
entries, but often "fast 1" and "fast 2" are intermingled in one dictionary entry.
Normally dictionaries are not very good at differentiating words whose meanings are very close. If you compare dictionary explanations of "fast" and "quick" you often find such definitions/explanations don't help
at all. Often dictionaries with up-to-date lexicology try to solve such problems by giving a special information box where more information about the use of words with similar meanings is given. But I haven't
seen such an information box for "fast" and "quick" yet.
Answer: In many cases the two words mean the same thing.

If you are encouraging people to hurry you may urge them on with either Do it quick! or Quick! or Do it fast! or Fast!
You may describe a good student as a quick learner or a fast learner.

But in other contexts they may have somewhat different meanings.

Fast tends to be used when you are speaking of the time it takes someone of something to move a given distance: a fast train, or a fast runner.
Quick tends to be used when you are speaking of how long it takes someone to respond to something: a quick answer to a question, or events following each other in quick succession.

The distinction is particularly marked in the way we speak about athletes. A batter in baseball, or a batsman in cricket, must have a quick eye, to react in a fraction of a second to the pitched or bowled ball. But when he runs he must be fast, to cover the distance between bases or wickets in as short a time as possible.
Answer: "Fast" and "quick". I think that these words are interchangeable when used as adjectives generally describing speed, but are less interchangeable ,or not at all interchangeable when used in adjectival phrases.
Adjectives
In their adjective forms, "fast" and "quick" are fairly similar ; look at their definitions.
fast adj. moving or able to move, operate, function, or take effect quickly; quick; swift; rapid
quick adj. done, proceeding, or occurring with promptness or rapidity, as an action, process
You can say:
The train is fast.
The train is quick.
Adjectival Phrases
While still being used as adjectives, "fast" and "quick" can have  specific meanings when modifying certain words.
fast adj. characterized by unrestrained conduct or lack of moral conventions, esp. in sexual relations; wanton; loose
ex. Nancy is fast, as evidenced by her way of speaking and her cheap clothes.
fast adj. firm in adherence; loyal; devoted
ex. Joe and Chris were fast friends until the day they died.
quick adj. easily provoked or excited
ex. Your father has always been quick tempered.
quick adj. prompt to understand, learn, etc.; of ready intelligence:
ex. George is  a quick student.
Answer: They have the same meaning. "Quick" or "Quickly" is slightly more formal. "Fast" is more likely to be encountered in casual conversation.
When I was teaching English in Korea, they had taught all of the kids to say "quick" and it sounded odd to me. "Fast" is more likely to be encountered in everyday conversation.
Comment: They do not have the same meaning.
Comment: Quick relates to acceleration, while fast relates to speed. One could have a very fast top speed but could take a long time to build up to that speed, while another could be very quick to react but their top speed might not be very fast.
Comment: @Jay You should consider editing your question to include the two sentences from the book.
Comment: Even as an adjective, they seem to have identical meanings to me. "The quick thief", "the fast thief". Can you elaborate?
Comment: Hmm. I think I got it. The author used quick for Jon cause he's slender and used fast for Robb cuz he's muscular who is less speedy

difference between ‘fast’ and ‘quick’


Would Yosef sleeping with the wife of Potifar have been a sin?

Question: My understanding from Sanhedrin 82a is that there is no halachic construct of marriage by non-Jews and as such Potifar(a)'s "wife" should not have been forbidden to Yosef. It was only later during the times of the Chashmonaim that a decree was made against this type of adultery. Why then does Yosef say it would be a sin to God (Bereshis 39:9)?
Comment: There's definitely marriage by non-Jews. How else could adultery be one of the seven Mitzvot for Bnei Noach? (The six forbidden relationships are mother, step-mother, sister, adultery, homosexuality, and bestiality. Rambam Kings 9:5)
Comment: Wouldn't it have been really mean to Potifar who had been nice to him? Is that not a sin?
Comment: It's possible that Yosef was saying that it would be a sin to G-d in terms of unethical behavior. I.e., Potiphar placed full trust in Yosef to the point where he wasn't concerned about leaving him alone with his wife. Potiphar assumes, of course that Yosef wouldn't do anything with his wife. If he finds out that he did, that would be a betrayal of trust to his employer, and that is the sin to G-d.
Comment: I haven't yet read the Sanhedrin page. But see Rash"i and Ramba"n, in particular on the verse that you alluded to. They state that *Bnei Noach* was also forbidden to have such illicit relationships. Yosef's statement that it would be a sin, according to Ramba"n was referring to his betraying his employer, Potiphar, as I explained above. Your question is vague, BTW. Do you want to know halahc of this relationship or what Yosef meant by his statement? These are separate aspects.
Comment: @DoubleAA you probably want to bring his atention to chapter 9 halacha 7 which can be found here http://www.chabad.org/1188354/
Answer: Yes, there is an issue of mitsvat asse  in bne noach from which we can say that it have been a sin. See Talmud Bavli Kiddushin 21b:

וראית בשביה ת"ר וראית בשביה בשעת שביה אשת ואפילו אשת איש
Our Rabbis taught: 'And thou seest among the captives' - when taking her captive; a woman - even married.

See Tosfot there

אשת אפילו אשת איש. ואע"פ דאין אישות בכותית כדאיתא פ' ד' מיתות (סנהדרין נב:) מ"מ איכא עשה דכתיב (בראשית ב) ודבק באשתו ולא באשת חבירו.:

Tosfot explains that despite that in Sanhedrin gemara says that there is no marrital status among bene Noach, there is a prohibition, derivated from a positive mitsva. The mitsva is "Therefore shall a man l....... , and shall cleave to his wife"
So the gemara in Kiddushin taugh that the special situation of yefat toar, can counter this prohibition. Without this mitsva,  it remains a sin.
Answer: There's another side of a coin. Here's some reasons why it was not / could not be / could be not a sin:

"Sin" is a matter of different perspectives. Remember Moses shattering the Luchot? Was it a sin? From our Halakhic perspective it was surely a sin of "לא תעשון כן לה"א" - a branch of idolatry (we're forbidden to loose Divrey Kodesh). But for Moses - it was a great merit (some other times he, however, greatly "failed"). So the situation with Yossef could turn out either way - either Hashem was praising Yossef for this idea, or scolding him - about 50% chance.
Before Matan Torah, the "self-emerged" Jews enjoyed a special status: they left the status of gentiles and did not yet reach the status of full Jews (hence the dispute on their status in Gemorah). This situation allowed them to be technically exempt from obeying the Mitzvot, as those were yet given in verbal and explicit form. So Yosef being a Jew was Potur of having relations with a married gentile woman, and he was yet to be commanded all the late prohibitions, like "haBoel Aramis", "Le Titchatnu", etc.
We hold Yosef to be a Tzadik not only in his deeds, but his intentions also. However (according to Shmuel), he had clear intentions to have sex with this woman as he saw in prophecy the two tribes (of his sons) coming from her descendants. If so I can conclude two possible explanations: either he didn't hold it to be a sin (as we wouldn't expect him to readily sin), or he had a better Mitzvah to do (see Yaakov with the two sisters, Yosef not honoring Yaakov for years etc).
Comment: "From our Halakhic perspective it was surely a sin of "לא תעשון כן לה"א" - a branch of idolatry (we're forbidden to loose Divrey Kodesh). But for Moses - it was a great merit" this smacks of sabbatian antinomianism. Judaism believes there is one law for everyone. A zaddiq can't sin, just because he's holy. Rishonim address lo taasun here. There is also the possibility of horaat shaa. Judaism doesn't believe that holy people can choose when they are above the law.
Comment: Well given that your are just some internet guy, your assertions about what Judaism believes are fairly useless, unless you can back them up.
Comment: "hence the dispute on their status in Gemorah" where is this alleged dispute?
Comment: "We hold Yosef to be a Tzadik not only in his deeds, but his intentions also." Who is 'we'? Is this the royal we?
Comment: My royal we stands for your "Judaism believes" :)


Updating Mac app shared with Family Sharing prompts for family member's password

Question: I'm trying to update a paid app, bought by a family member but shared with family sharing, on the Mac App Store, and it prompts me for the password. The Apple ID is the family member's, and greyed out so I can't change it. I don't think we're supposed to share all our passwords in order to use Family Sharing, right?
Answer: TL;DR - It's possible you have a problem with date / certificates or Apple messed up server side - contacting support to figure out a workaround is likely the "answer" and you probably didn't make this happen.

This is an aggravating bug and it has been around for quite some time (from iOS 9 to iOS 10 is when I first experienced it).
I'm certain it's a bug since I never, ever have used the password for the other two members of the family that buys apps that I then installed using the App Store and my ID / password. Also - if this was broken for everyone, all the time, it would be explained in a KB article or fixed.
I have yet to have anyone from Apple support end up with anything other then ¯\_(ツ)_/¯ and I have to delete the apps and reinstall them.
I hope someone else can get more details or point out something I've missed and even better, I hope I can come back and edit this to say it's fixed when that day comes.


Checking Singapore CPF account after PR expiry

Question: I received my SPR in 2002 and expired in 2007. I did not withdraw my CPF contribution. I want to know how much I have in my account and tried to check online. I forgot my signpass password and tried to retrieve my password but the system denied stating my personal detail is invalid. How can I retrieve my account? Why the system denied my personal information as I entered correctly.
Comment: I'm voting to close this question as off-topic because the OP needs to contact the Help team for the system they're trying to access
Comment: @Traveller This is about checking pension balance, not just logging in.
Answer: If your SingPass is no longer valid, you cannot do it online, but you can contact CPF and ask them to give you a statement:

You can also email email@example.com, call 1800-227-1188 or visit any of our CPF Service Centres for a printed copy of your Yearly Statement of Account. Please note that an administrative fee would be chargeable if you would like to have a copy of your statement to be mailed to you.

Source: https://www.cpf.gov.sg/members/FAQ/schemes/other-matters/others/FAQDetails?category=other+matters&group=Others&ajfaqid=2192013&folderid=13700


How to test chain reorganization with testrpc?

Question: I am working on blockchain synchronization script. I need a way to make reorganization programmatically for testing purposes. Is there such functionality in some testrpc?
Answer: I don't know of a way to accomplish that with TestRPC. There might be a better way than described below.
I think I would make a private chain with Geth and low-difficulty/fast blocks in the genesis block.

Connect two nodes to each other and make sure both are mining and synchronized. Deploy your contracts, set up accounts and balances (they will each be earning mining rewards) and otherwise get ready for the test - generally, create the initial test conditions.

Then, break the connectivity between the nodes. To do that progamatically you could consider stomping on the network configuration. The idea is to create a "split-brain". You can then start submitting transactions to one node or the other, or even both. You can arrange it so Geth on localhost still responds even though connectivity to the other node is lost.
Since both nodes will be mining, they will each form block histories, but they will be divergent histories.

Restore the connection between the nodes and expect reorganization until one canonical history emerges on both nodes.

Hope it helps.
p.s. As an afterthought, a crude variation would be to use three nodes and force one to drop out while two stay connected, with all three mining. That would all but guarantee that conjoined nodes would have the longer chain and the dropped-out node will be the victim of the reorganization. Knowing that in advance might simplify your probing of the results.
Answer: It wouldnt be possible to do it with test rpc as it only mints blocks when transactions arrives, and isnt connected to other remote nodes, so there would never be discrepancies between nodes.
We have done this recently using private chains and some chaos tool .. pumba. Pumba will allow you to kill nodes, restart them and introduce latency and drop packets.
Any of these adverse scenarios will result in reorgs once the nodes come back online


Do the Existence of Mobius Strips Prove that Mathematical Platonism is True?

Question: Consider Mobius strips (eg. strips of paper with one or more half-twists joined together at the ends--for example, a Mobius strip with one half-twist has the interesting property of having only one side...).  As anyone who has had a chance (either as a child or as an adult) to play (i.e. to cut them down the middle lengthwise for example) with such objects can verify, these objects have very interesting properties.  It also seems a trivial observation that these strips of paper (or any other material that can be so twisted) so constructed constitute real mathematical objects and therefore mathematical Platonism is true.  What, if anything, is wrong with this argument?  Another question I find of interest regards the half-twists that give these objects their interesting properties.  What sort of property are these half-twists and what are they properties of since any material that can be given half-twists and can be joined at the ends become these 'real' mathematical objects by the operations of twisting by half-twists and joining at the ends?
Comment: What makes you say that such bent strip of paper is a "real mathematical object"?
Comment: by the same token any object would be an "instantiation" of a number of formula describing some of its properties. The mathematical Möbius strip shares some properties with the paper if don't look too critically on the paper and ignore its thickness, surface quality, micro- and atomic structure etc. But each of the properties that paper Möbius strip doesn't share with the abstract one it shares with some other mathematical model. But that's the whole point of having the models, so it's neither surprising nor interesting.
Comment: Very simple.  Take a strip of paper, give it a half-twist, and join it at the ends.  Then cut it length-wise down the middle.  Now take another strip of paper and simply join the two ends then cut this strip length-wise down the middle.  One can easily see that the results from cutting each strip length-wise down the middle are different for each strip so constructed.  This suggests to me that giving a strip of paper (as one instantiation) a half-twist and joining it at the ends has real consequences in the real world (I assume the same naive realism that informs us that jumping off
Comment: a tall building will lead to disastrous consequences...).  This being the case, it would seem reasonable to conclude that the paper instantiation of the mathematical abstraction known as the 'Mobius Strip' is a real mathematical object because it is an instantiation in 'reality' of that mathematical abstraction.
Answer: Mobius strips aren't that interesting physically because they're all just rings.  Everything is three-dimensional.  If you took a noodle and squashed it so it was 30% wider than it was tall, and instead of doing it flat you did a half-revolution so that one edge of the bulge went from left to up to right, you'd have a "Mobius strip" of a sort.  But it's a really unimpressive one because the curvature is still nearly constant as you travel around (rather than along) the noodle.
Doing it with paper just makes the aspect ratio more and more extreme.  You can squash your noodle into a Y shape had have it rotate by 120 degrees also to get an interesting shape (if you forbid yourself from going over the high-curvature "edge").  I don't think any of this proves anything about the reality of objects, but it demonstrates that practical geometry is fun.
Comment: See my comment to Neil.
Answer: Some of your questions might be better addressed on Mathematics.SE. However, I would address the philosophical content of your question as follows.

It also seems a trivial observation that these strips of paper [...] constitute real mathematical objects and therefore mathematical Platonism is true. What, if anything, is wrong with this argument?

Just because a physical object can be described well by a model, consisting of a mathematical "object" which one might describe as having "very interesting properties", does not imply that the mathematical object is any more than an abstraction with which you can describe the physical object (or a class of similar physical objects).
This is especially clear when those very interesting properties are made with reference to imaginary physical models. What does it mean to cut the ideal Möbius strip down the middle, when you don't have manual access to it and it is in any case presumed to be eternal and unchanging? What you're doing is imagining the Platonic ideal as if it were a physical object, or at the very least imagining a model where certain details are fixed — the Platonic Möbius Strip That Is Made Of A Continuous Strip Of Some Quite Flat And Easily Cut Material — in order to express properties about physical models which you would somehow like to ascribe to the Platonic ideal.
The problem with the argument is that you equivocated between the abstraction and the real; between the map — represented by The Möbius Strip, with capital letters — and the territory, which is a single instance of a strip of paper cut and twisted so that the most natural description of it in terms of metric spaces (as opposed to material science) is as a finite non-orientable 2-manifold of a certain well-known kind which we call "Möbius strips".
Comment: @Thomas: mathematics is effective is because we have made it so; and engineers and physicists equivocate between models is because it is convenient as shorthand. But it's no basis for ontology. That the world is orderly (often admitting succinct description) is potentially interesting; mathematics is just the name for our tool for contemplating structures similar to those we see in the world. I've equivocated between a literal map and its territory many times, but with the understanding that my fellow-travellers would understand that the map was only useful in reference to the physical world.
Comment: @Neil:  Don't engineers make essentially the same equivocation between the abstract and the real?  Isn't this equivocation between the abstract and the real the reason we observe the 'unreasonable effectiveness of mathematics' in describing the physical world?  The very fact that one can construct a finite non-orientable 2-manifold known a "Mobius Strip" in the 'real world' with its associated 'real consequences' would seem to suggest that such a finite non-orientable 2-manifold is real?
Answer: No, not particularly. What it shows is that the idea of two sides is more subtle than one may believe without reflecting on an example as you've pointed out.
For the instrumental definition you've given it is true that the strip has one side.
But why is it confusing to someone that hasn't come across a mobius strip? This is because there's alternate definition of sides. To wit, go down through the material of the mobius strip and if you emerge again then it has another side. If you had an infinite thick strip for example, you wouldn't be able to get to the other side.
All this shows is the ambiguity of definition.
Comment: Your alternative definition of 'sides' is a poor definition of sides, I think, because you still need to rely on the instrumental definition.  Consider, If you had a very thick Mobius Strip (say, twenty feet thick) and you drilled a tunnel to 'the other side', how would you determine that the side you drilled to is really the 'other side'?
Comment: A way to do this is to mark the initial drill site with one color and the site you drilled to with another.  If in fact you actually drilled to the other side you could walk around the surface back to the drill site and only see the color of the final drill site.  Imagine your surprise....
Comment: @Benjamin: It is from a geometrical point of view, perhaps. But people are not geometers, I'm describing *side* as would be commonly understood in terms of human psychology & perception. Why must I choose a definition that is *geometrical* in character? You're confusing the world of abstraction with the world-as-its-given out there in a similar way to the OP.


File Data Processor

Question: I have to process tons of text/html files. Im looking for a tool that helps me to create a graph with processing nodes in order to make transformations on this files. For instance:
- A node loads the file that have an specific exntension.
- This node is conected to other that checks if the file contains some word.
- Other node is able to receibe a file and transform it to a text stream,
- Other node is able to make some text replacement...
- etc...
What its the closest tool to do that?
Regards.
Comment: Are you specifically trying to avoid programming in Python (for instance)?
Answer: You are describing a type of process which the *nix toolchain design is suited: a suite of text-processing tools that each operate upon a file or text stream in sequence, each doing a simple operation and passing the output on to the next tool in the sequence.
grep is a program that is designed to be used in this way and that can be used to check whether a file contains some word or pattern.
There is no *nix tool that I know of that is specifically designed to strip HTML tags (if that's what you mean by "transform it to a text stream"), but you could easily create a simple tool to do this.  See, for example, https://stackoverflow.com/questions/753052/strip-html-from-strings-in-python for suggestions on how to do this, or the strip_tags() function in PHP.
Depending on what the other steps are in your file processing workflow, you may find existing tools that do the job, or you may need to create some tools of your own.
The overall process may be controlled by a shell script (or batch file on Windows), particularly if you have conditions to evaluate and multiple paths that might be taken--for example, depending on whether or not a certain word is found.

File Data Processor


Webdriver : To upload images using the sendkeys() and autoit tool

Question: What is the difference between using sendkeys() and autoit, which helps to upload images.
Answer: Sendkeys( ) is a command used for sending input from the keyboard e.g. for entering some value in the input field, the keys/values typed inside the Sendkeys( ) command will be entered in the respective field during execution of test for web based applications. They are confined to the browser. Using SendKeys() command you can directly set the path of the file to be uploaded in the respective Upload file field, so when this line of code is executed your upload field will have the specified file as attached but it will not open the windows explorer for finding and attaching the file. It may get fail sometimes, depending upon the application (although in the tests created by me, I haven't seen it getting failed) but have seen related posts over SO and SQAForums.
While AutoIt is used to interact with the desktop to do things like downloads & uploads. Automating these sorts of workflow is tricky in Selenium. Using AutoIt (3rd party) in Selenium helps in recording and executing desktop based scenarios. You can create your desktop interaction scripts in AutoIT and then call it from your Selenium test scripts. This is a more efficient method of handling Windows pop-ups and dialogues.
Answer: It are two ways of populating an HTML INPUT type FILE form field.

SendKeys works on all operating systems and for all browsers where you can set the internal value of the INPUT field
Auto-IT works only on Windows and should only be used for browsers where you cannot manipulate the internal INPUT field value

Not sure why people would prefer the Auto-IT version, I would always try and get the SendKeys version working. I would get developers to change the file upload to use INPUT, so that the SendKeys version works.


Skydrive creates a .lnk file after I upload a folder

Question: I have installed Skydrive on my PC which uses Windows 7, and when I drag a folder across to my skydrive folder on my pc, i then have the green tick, but when I look on Outlook.com, all I see is a .lnk file with the same name as my folder, not the folder I have copied across or its contents. e.g. dragged across folder called 'steve' to skydrive folder on pc, it shows with a green tick next to it in the skydrive folder, but when I look on web Outlook (https://skydrive.live.com), all I see is 'steve.lnk' if I click that it says 'downloaded' !? When I look at the download file its 6k and just seems rubbish.  Oddly, I have tried the same thing with a folder which has only a few files, and it works fine. Can anyone help?
Comment: It seems like you copied a shortcut instead of the folder itself.
Comment: you are right, thanks very much for putting me out of my misery :)
Answer: Thank you to @FSMaxB for answering this for me above. This could have proved to be a costly error further down the line, glad I queried this.
"It seems like you copied a shortcut instead of the folder itself. – FSMaxB "


One tetrahedron inside another tetrahedron

Question: Consider two tetrahedrons one placed inside the other.
Prove that the sum of all 6 sides of inner tetrahedron is at most the sum of the 6 sides of exterior tetrahedron.
Comment: After thinking about it a bit, it probably isn't a homework question, because it is false... the outer tetrahedron can have side lengths close to 2, 2, 0, 1, 1, and 1, and the inner tetrahedron can have side lengths close to 2, 2, 2, 2, 0, and 0.
Comment: Finding the maximal possible ratio of side sums (4/3) was a problem at the International mathematical olympiad long ago.
Comment: This looks like homework to me...
Comment: This is (if true) a nice problem, but it is more appropriate to an Olmpiad/Putnam competition than to research mathematics. You'd probably get both a more positive reception and better answers at http://www.artofproblemsolving.com/Forum/index.php .
Comment: The origin of this question is the prior question http://mathoverflow.net/questions/79621/two-rectangular-parallelepiped
Answer: The question as stated is false, be we can salvage it by answering the following question: what's the biggest possible ratio of the sum of the inner tetrahedron's edges to the sum of the outer tetrahedron's edges?
To approach problems like this, there is the very useful trick of noticing that the distance between two points is a convex function of either point. If we assume the outer tetrahedron is fixed, and fix three of the vertices of the inner tetrahedron, then since the interior of the outer tetrahedron is convex, the sum of the side lengths of the inner tetrahedron, as a function of the last vertex, is maximized when the last vertex is at an extreme point of the outer tetrahedron. Repeating this argument for each vertex of the inner tetrahedron, we can reduce to the degenerate cases where the inner tetrahedron has all of its vertices on the vertices of the outer tetrahedron. We have several cases:

The inner tetrahedron and the outer tetrahedron are the same. Then the sums of the side lengths are equal.
The inner tetrahedron is a face of the outer tetrahedron, with one of the vertices repeated. Suppose the outer tetrahedron has vertices $ABCD$, and the inner tetrahedron has vertices $AABC$. Then the sum of the lengths of the inner tetrahedron is $0+2AB+2AC+BC \le \frac{4}{3}AB + \frac{2}{3}(AD+BD) + \frac{4}{3}AC + \frac{2}{3}(AD+CD) + BC$ $\le \frac{4}{3}(AB+AC+BC+AD+BD+CD)$, and we have equality if the outer tetrahedron is degenerate, with $B=C=D$.
The inner tetrahedron is a side of the outer tetrahedron. Suppose the outer tetrahedron has vertices $ABCD$, and the inner tetrahedron has vertices $AABB$. Then the sum of the side lengths of the inner tetrahedron is $0+0+4AB \le \frac{4}{3}AB + \frac{4}{3}(AC+BC) + \frac{4}{3}(AD+BD)$ $\le \frac{4}{3}(AB+AC+BC+AD+BD+CD)$, with equality when $C = D$ and $C$ is on the line segment $AB$.

Thus, the sum of the side lengths of the inner tetrahedron is at most $\frac{4}{3}$ times the sum of the side lengths of the outer tetrahedron.
Comment: Perhaps you'd like to mention, for the peace of mind, also the easy (not sharp) case $AAAB$.
Answer: The conjecture about the quotient of the sums of the lengths of edges for a tetrahedron inside another was formulated (a long time ago) by Jerzy Browkin, who saw that, somewhat paradoxically it can be greater than 1, and even arbitrarily close to 4/3, as his examples proved it. He asked if   $\frac 43$   is the least upper bound of such quotients.
The conjecture was solved in 1961 by Wlodzimierz Kuperberg and myself. We published it in 1962 or 1963, in Polish, in Wiadomosci Matematyczne (of Polish Mathematical Society). Years later an English translation was published in Alabama Journal of Mathematics (or similar). And a powerful complete multidimensional generalization was obtained and published by Carl Linderholm, An inequality for simplices .
Ancient Greeks could easily formulate and solve the given problem (in 3d) but (as long as we know) never did--it took Jerzy Browkin to raise it.
Comment: I have added the name (Carl Linderholm) of the mathematician who obtained the ultimate (finite-dimensional, geometric) generalization of the tetrahedra result + link.
Answer: Sum of the 6 edges of the inner tetrahedron can be larger than the sum of the 6 edges of the outer tetrahedron.
Imagine the outer tetrahedron with 3 sides of 1000 and 3 sides of 1. The inner tetrahedron has 2 vertices close to the top and 2 vertices close to the bottom.
Sum of outer = 1000+1000+1000+1+1+1=3003
Sum of inner = 990+990+990+990+1+1= 3962
enter image description here
Comment: I believe your answer is subsumed by the accepted one.


Cyclopentane conformations

Question: What is the energy minimum of cyclopentane conformational diagram: the halfchair or envelope? How does cyclopentane flip?
Answer: As you mention, there are two main conformations that cyclopentane may adopt.

In the absence of substituents around the ring, there is actually only a $\pu{0.5 kcal/mol}$ energy difference between envelope and half-chair (envelope slightly lower in energy) meaning cyclopentane itself (computationally at least) is in rapid equilibration with no 'major' conformation as is observed with cyclohexane. (Note that the energy of the totally planar conformation is about $\pu{5 kcal/mol}$ higher than that of the both bent conformations, and so is not observed to any great degree).
With a single substituent on the ring however, such as a methyl group, the envelope conformation becomes slightly more favourable (to the tune of around $\pu{3.5 kcal/mol}$) giving a barrier to the ring flipping and meaning there is a dominant conformation.
Comment: The left envelope is equal to the right. I think the diagram was just intending to show that to get between two different envelope conformations you have to go via the half chair, which, for unsubstituted cyclopentane has little barrier is fine.
Comment: "In the absence of substituents around the ring, there is actually only a 0.5 kcal/mol energy difference between envelop and half-chair meaning cyclopentane itself" In favor of which one?
Comment: Are in the envelope conformation the C atoms in a plane, except the rightmost one?
Comment: Yes. So in the envelope conformation just one carbon is bent out of the plan
Comment: Why do you show two C$_s$ envelope conformations? Is not the left one the same as the right after a rotation.  As all the 5 possible envelope-half-chairs are equally probable surely only one envelope and half chair is needed ? As thermal energy is approx 2.4 kJ/mol  interconversion should be very rapid, I'm guessing but $10^8$ s$^{-1}$ would not be unreasonable.
Comment: Which one is the most stable: envelope or halfchair?
Comment: Envelope, but only by 0.5 kcal/mol (computationally). The take home message is that in the absence of substituents there isn't really a 'most stable' conformation, its in totally rapid equilibration.

Cyclopentane conformations


BPSK bandwidth for symbols not integer wavelengths

Question: Most of the BPSK waveform examples in text books/online are for carrier frequencies that are integer multiples of the bit rate. This means that when the symbol polarity changes there is a discontinuity in the waveform - but it doesn't jump signal level, it just heads the other way. When the carrier frequency is not an integer multiple, the waveform does need to jump instantly from one signal level to another (ie the symbol change takes place when the signal level is not at signal level 0)..
Does this increase required bandwidth or have any other undesirable effects??
Answer: The examples in the textbook are chosen for clarity. They will have like what, a 2:1 ratio between carrier and data frequency? In practice this may be 10 000:1 or more. And even with the carrier being an exact multiple you can't be sure of the phase; chances that zero crossings of carrier and data coincide are slim.
You need a higher bandwidth to get the sudden changes in level right, but if you have 10 000 carrier sines for 1 bit you don't care about that distortion in the first sine.
I wouldn't worry about it.
Answer: Any jump in the time domain has a very wide bandwidth in the frequency domain (theoretically infinite).  So an encoding that has jumps usually needs to be lowpass or bandpass filtered (or will be by the channel).  Thus the received signal won't have the discontinuity, but some smoothed (filtered) interpolation for some transition time (with a duration depending on the narrowness of the filter).  Decoding can be slightly complicated in that it has to ignore or compensate for this periodic waveform distortion, compared with phase synchronous modulation.  But that's usually done as a normal part of the decoding process.


Unity: Restrict movement inside a gameobject (2D)

Question: I've been sort of trying my own thing but it's super buggy so I'd like to see what other people have done to create moveable spaces. In essence, I just want to restrict my character's movement to inside of a sprite. So one of my sprites is the character  and another one of my sprites is a box -- I want to make it so my character can't leave the box. I've been modifying transform.position on mouse click in order to move my character, but now I'm not sure if this was the smartest idea.
Comment: Is your containing object always a box (ie. a rectangle) or do you want to support other shapes based on 2D colliders (circle, polygon), or based on the pixel opacity values in the sprite?
Comment: One of the problems with my first solution was that it only worked for rectangles -- I want it to work for any shape of the sprite
Comment: The thing about sprites is that they are inherently rectangular--they are literally a Rect on a Texture2D.
You're going to have to analyze your sprite for opacity, like DMGreg mentioned.  Check each pixel, if it has alpha of less than 255, create a 1-pixel large collider.  This will have performance issues with high-res maps.
We'd probably need more context on why you need this method to suggest other avenues of action.
Answer: If you're moving the transform relative to the wrapping parent, you could always Mathf.Clamp(high,low) your coordinates.
If not a box, I think you need to defer movement to physics engine for desired functionality.
Comment: Got an idea on how to do the latter? I sort of want something like the inverse of a polygon collider 2d, if that makes sense.
Answer: 2 ideas came to my mind. Look at illustrations:

First option is obvious, add colliders to boundaries of your game area.
The second option is, to limit your characters movement inside boundaries within your script.
For example, if you have a code that controls the position of character, check if your values falls inside the boundaries of your game area, then clamp it to max and min values if it exceeds.
Thankfully, unity has this feature built-in in Mathf library with "Mathf.Clamp" function. So in this example you need to check like this:
var finalVertical = Mathf.Clamp (rawVertical, -c, +c);
var finalHorizontal = Mathf.Clamp (rawHorizontal, -a, +b);

For more information about clamp, check this out:
http://docs.unity3d.com/ScriptReference/Mathf.Clamp.html
Comment: Instead of having four (or six in a 3d game) colliders as barriers around your play area and reacting on `OnTriggerEnter`, you can alternatively have one collider representing the game area and react on `OnTriggerLeave`. This has the advantage that you don't need to worry about having the outer colliders too small so an object with an extremely high speed can clip out of them.


Schengen duration of stay

Question: I currently have a type C visa (mult-entry for 90 days) issued from 30-07-2016 until 12-11-2016 by the Netherlands embassy. I want to travel on the 07-11-2016, my first entry port will be France, does this mean the duration of my stay will only be 6 days?
Answer: Yes.  If you want to stay after your visa expires, you should apply for another visa before your trip (it is not possible to apply for a visa once you're in the Schengen area).  If they grant it, it will be valid from 13-11-2016.  You will still need to comply with the 90/180 rule, independent of the fact that you have two visas.
The country to which you apply should be the main destination of your trip.  The port of entry is not relevant unless your trip doesn't have a single main destination.
Comment: @Angola: Correct -- the Schengen area follows the principle that a valid visa (or residence permit) is required for _being present_ in the area, not merely for entering through the border.
Comment: @Angola I've edited the answer to correct an important omission: you need to get your second visa *before your trip.*
Comment: Ok, this means Schengen visa is not the same as other visas, for example a South Africans visa starts to counts on the day of your arrival, if your visa was issued from 30-07-2016 until 12-11-2016, and you arrive on the 11-11-2016, you will be given 30 days of stay in South Africa.

Schengen duration of stay


app to locate star by coordinates

Question: I've named a star and would love to be able to find it in the sky - is there an app I can use to locate stars given a specific coordinate?
Answer: There are apps which will help guide you to more significant stars (Google skymap comes to mind if you're looking for a simple mobile system - Stellarium may also be a good option), but it's highly unlikely that any app will include the location and names of so-called 'personal' stars, as the bodies who sell such things don't have any the authority to do so and are not generally recognized in the actual world of Astronomy.
Note that the IAU (International Astronomy Union) is the body generally recognized to have the responsibility of naming and classification of stars and other bodies. They also come out strongly against such practices and services:

As an international scientific organization, the IAU dissociates itself entirely from the commercial practice of "selling" fictitious star names or "real estate" on other planets or moons in the Solar System. Accordingly, the IAU maintains no list of the (several competing) enterprises in this business in individual countries of the world.  Readers wanting to contact such enterprises despite the explanations given below should search commercial directories in their country of origin.

Link to IAU page on buying of star names
Comment: Thank you for pointing me to the link on buying star names "scam"!  My wife bought me a star name a while back, and it was very sweet.  It is good to know the truth behind it though that the names are not stored in an official national database and are not official.
Answer: Alternatively, if you were to get the Right Ascension and Declination coordinates from the company that sold you the star you could use a database like SIMBAD to find the actual designation of the star you purchased.
You could then probably use the SIMBAD designation to find the star using Stellarium.
Here's a link to the SIMBAD database: http://simbad.u-strasbg.fr/simbad/sim-fcoo
I hope this helps!

app to locate star by coordinates


When madhiyy touches to clothes can i have to do ghusal

Question: Asslamoalaikuum to all of my brothers and sisters .. Well my question is only that i know when madhiyy comes out then you don't need to do ghusal but if madhiyy touches to your cloth then we have to do ghusal or just wash our clothes at the point where madhiyy touches ? Plz answer simple that only u have to wash your cloth at the point where madhiyy touches or that you have to do ghusal plzz in simple english iam not good in English plz Answer It's very necessary for me
Comment: Why should the same reason of impurity create two different rulings?
Comment: Sorry I didn't get that plz in simple language iam not good in english when only madhiyy comes not maniyy and when that madhiyy touches to clothes then we have to just wash the cloth at the point where ever madhiyy touches or we have to change the clothes and do ghusal ? plz in Simple english
Answer: Brother please do not tell me that you have not been making ghusl every time semen has come out?
You MUST make ghusl everytime maniy comes out! Everytime you ejaculate/come and there is white semen visible, you must do a fard ghusl. This is Maniy.
Wadiy is preseminal fluid or the watery substance that comes before Madiy. This requires wudu not ghusl.
There is one case in which Maniy does not necessitate ghusl but do not worry about that: just make sure you are making ghusl everytime semen comes out to be on the safe side.
You must wash the part of the clothing where semen has fallen until it is very clean. Rinse 3 times if needed minimum. As for dry semen, Aisha peace be upon her scraped dry semen/Madiy off the clothing of the Prophet.
In another Hadith, it mentioned washing as well.
'Amr b. Maimun said:
I asked Sulaiman b. Yasar whether the semen that gets on to the garment of a person should be washed or not. He replied: A'isha told me: The Messenger of Allah (ﷺ) washed the semen, and then went out for prayer in that very garment and I saw the mark of washing on it.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، عَنْ عَمْرِو بْنِ مَيْمُونٍ، قَالَ سَأَلْتُ سُلَيْمَانَ بْنَ يَسَارٍ عَنِ الْمَنِيِّ، يُصِيبُ ثَوْبَ الرَّجُلِ أَيَغْسِلُهُ أَمْ يَغْسِلُ الثَّوْبَ فَقَالَ أَخْبَرَتْنِي عَائِشَةُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَغْسِلُ الْمَنِيَّ ثُمَّ يَخْرُجُ إِلَى الصَّلاَةِ فِي ذَلِكَ الثَّوْبِ وَأَنَا أَنْظُرُ إِلَى أَثَرِ الْغَسْلِ
Be safe brother, take these things very seriously and may Allah reward you,
Salaam.
Comment: The Hadith you quoted itself says مَنِي. Madhiy is different from maniy, and it is not semen


How to buy Apple products with Bitcoin?

Question: How can I buy Apple products? I want to buy the new iPad Mini, and I'd use Gyft to convert BTC to Amazon credit, but the new iPad is not yet on Amazon. Is there any way to buy the new iPad Mini, either directly through Apple or through a 3rd party?
Comment: This question is off-topic because it is asking for a service recommendation, and too broad, because it doesn't specify necessary information such as the country you want to buy the product in.
Answer: Disregarding anything clever (I am still pretty new to this), you can simply convert your Bitcoins to your local currency through a third party.  There will be a transaction fee (I imagine), but I doubt Apple is going to hop on the BTC wagon anytime soon and their business model, AFAIK, won't allow for the same lever of third-party integration as Amazon does.
Comment: Yes, I thought of this but I don't want to have to pay tax on BTC -> USD. That conversion would be taxed as a sale of assets, I think.
Answer: To answer my own question: there are Apple Product websites listed on the Hidden Wiki, supposedly selling Apple products directly for BTC.

How to buy Apple products with Bitcoin?


Transfer content from one Apple ID to another?

Question: My daughter was using my Apple ID with her Ipad mini. I want her to use her own Apple ID now that she is old enough. How can we transfer the content of her ipad mini, ( music, photos, apps) particularly game apps WITH THEIR DATA onto her new account? She doesn't want to start from scratch with all her games.
Answer: You cannot. It's not possible to share content from one Apple ID to another. Apple actually recommends everyone have their own Apple ID.
You can load the content on your daughter's device and she can access them all normally. You can then log her into her own Apple ID, where she can begin to make her purchases on her own account. The only downside is she will have to know your Apple ID's password as iOS will ask for it on rare occasions (when restoring the device for example). It's possible to store content from multiple Apple accounts on a single device, the user will just need to enter the password should the OS ever require it. That is the only feasible solution in your case (other than starting over). This will at least circumvent having to re-purchase any content.
This has always been a sore spot for Apple customers as they have historically been very firm in never being able to even close an Apple ID, let alone share content between them.
You can read more about Apple IDs here: http://support.apple.com/kb/HT5622?viewlocale=en_US&locale=en_US
Comment: it *is* possible to copy the data only, though not straightforward: http://apple.stackexchange.com/questions/91291/transfer-ios-app-data-to-a-different-account
Comment: Your comments were very useful. However, Regarding the fact that Apple doesn't recommend using the same Apple ID, I don't think parents have a choice:  they have to share their Apple ID with their kid when s/he gets an Apple device and needs to download music or apps, since kids are not allowed to set up their own Apple ID if they're less than 13 years old.
Answer: With the release of iOS 8, you can.
There is a new feature called family sharing which allows you sync purchases from 1 apple ID to another. You could set up a family with your daughter where she can re-download her games.
If she wants her data (progress ect.) you could use apps like iFunBox to extract the data and transfer it to another iPhone.
Answer: If all the paid applications associated with your Apple ID is for your daughter then give her your Apple ID and create another Apple ID for yourself. Do not worry about your free applicationS as you can purchase them again for free in your new Apple ID.
Answer: in iOS 8 you can turn on family sharing on your account and hers and she can download her games from your shared apps.


UAE visa question

Question: I hold an Indian passport and traveling from Sofia to India.
Which visa should I apply for Dubai with a 7 hour layover (Exactly 6 hour 55 minutes) in Dubai? I am reaching DWC airport from SOF airport at 20:10 hours on 2nd October, next flight is from DXB airport to BLR airport at 03:05 hours on 3rd October.
96 hours transit visas require at least 8 hours of transit time and I have 6 hours 55 minutes transit time.
Is there a chance to get 96 hours transit visa ?
Comment: I don't think you can get 96 hour transit visas on arrival at DWC. Timatic doesn't say you can, so you'll likely be denied boarding at Sofia, unless you get a visa in advance.
Answer: As your itinerary falls just short the requirements, the 96-hour visa on arrival does not appear to be an option. Additionally, your arrival and departure are at two separate airports.
Should you be flying either Etihad or Emirates, you can apply on the web site of either airline. Wikipedia also lists Air Arabia, Air Astana, Air Baltic, Air Serbia, flydubai, Turkish Airlines, and Indigo Airlines as airlines through which UAE visas can be arranged, but you should check and confirm with your carrier.
Otherwise, you would need to make arrangements for a visa prior to your journey.

UAE visa question


root port election in STP

Question: I have a question about root-port election in STP.
How to determine root-port on switch 3, both fa0/1 and fa0/2 have port-cost back to root switch (switch 0) of 38, receive BPDU from port fa0/3 of switch 2.
Any other tie-breaker in this case.
As result of simulation, f0/1 is root-port of switch 3.
Thanh you so much.
Comment: I was about to edit the question, but I can not wrap my head around about ", receive BPDU from port fa0/3 of switch 2." , please provide further clarification.
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
Answer: The root port on a device is the lowest cost interface facing the root bridge. If there's a tie the lowest port ID is selected.
Since you've got a hub in between S2 and S3, S3 is receiving the exact same BPDUs from S2 on both ports and BPDUs from one of its own ports on the other. While this doesn't really hurt S3, S2 will be confused because it receives conflicting BPDUs from two different interfaces of the same bridge on a single interface. Using a hub breaks spanning tree and shouldn't be done.
Additionally, this setup doesn't make much sense. While S3 has two interfaces towards the rest of the network, both interfaces are connected to the same repeater and thus belong to the same collision domain. Only one port can be used at any time.

root port election in STP


Difference between "Quittung" and "Beleg"? What is the german word for receipt?

Question: This has puzzled me for some time. I am wondering what is the german word used for "receipt" when used in a transaction for instance, when paying for a drink in a german pub, which word is written on top of the receipt? Searching in the online pons dictionary I found both the words Quittung and Beleg with no striking difference, so, do they mean the same in this context?
Comment: You usually ask for the Rechnung in a restaurant or pub: "Wir hätten gerne die Rechnung, bitte."
Comment: In der Kneipe ist die Frage nach einem Beleg für einen Drink eher ungewöhnlich. Ansonsten erhält man von Kassensystemen i.d.R. nur einen Bon, eine kurzen Beleg ohne Angabe des Kundennamens.
Answer: Beleg has a broader meaning than Quittung.
A Quittung is a written confirmation that a payment or some other benefit has been received. There is also a verb quittieren, which stands for writing a Quittung.
Beleg comes from belegen (to prove). A Beleg is a document that proves something. A Quittung is a Beleg, but a Beleg doesn't have to be a Quittung. For example, an invoice can serve as a Beleg (that some goods have been delivered or some service has been provided) but it's not a Quittung because it's written by the provider and not by the recipient.
Comment: There are further forms to specify the Beleg: Zahlungsbeleg or Rechnungsbeleg.
Comment: As you mention "quittieren", it should also be noted that "quittieren" can be used in quite a wider sense than "writing a Quitting". I'd consider "quittieren" roughly synonymous with "zur Kenntnis nehmen" ("to acknowledge"). "Quitting" can also be used in a figurative sense (not referring to a piece of writing), but that figurative usage stays much closer to the general concept of a "Quitting" IMHO than the verb "quittieren".
Comment: In "den Dienst quittieren" steht es aber nicht für "zur Kenntnis nehmen", sondern für abschließen.
Comment: @userunknown: Stimmt, die Bedeutung gibt es auch noch.
Answer: As mentioned in the comment by "infinitezero", you will ask for the "Rechnung" in a restaurant or pub. You will also get a "Rechnung" in case of buying more expensive items in a shop.
The term "Rechnung" has different meanings depending on the law in which context it is used.
In general, most trades require that a "Rechnung" is printed and handed over to the customer. In this terminology, each "Quittung" or "Kassabeleg" must have a unique fiscal identifier in austria (a QR code). Then it can be seen as "Rechnung".
In addition, Austrian law and I assume it's very similar in Germany, the clerks define minimum requirements for a "Rechnung" in terms of V.A.T. laws, (e.g. a unique number, address and name of both seller and buyer). This case of "Rechnung" I would translate to "invoice". If you pay cash, then the "Rechnung" is standalone with text remark "paid with cash". If you pay with credit/debit card, the "Quittung" (voucher / receipt for payment) is separately printed and in many cases stapled with the invoice.
But for smaller things you will just get a "Quittung", "Beleg" or "Kassenbeleg" (receipt) which is printed directly from the casher's desk often w/o having payment or buyer information. In some situations this receipt contains all the formal requirements of an invoice, and then the "Beleg" is a "Rechnung".
Comment: But especially in a restaurant or pub, asking for the "Rechnung" will, at first, often just get you a sheet of paper with a hand-written addition of the individual items and the sum you have to pay. Presumably, it's only after that that you get something printed (and I'd probably ask for a "Beleg" then), for instance, if you expect to get reimbursed by someone else for the expenses and need some proof.


Enable-Migrations gives Exception calling "SetData" with "2" argument(s) error

Question: I have used Entity Framework migrations numerous times before, but I am unable to enable migrations in a new demo project I just created. I have tried the different options recommended on SO Posts but nothing seems to work. Here is how the project was created (essentially following Julia Lerman's book example):

Created a blank Visual Studio solution
Added class library project for Models, DataAccess (.NET standard)
Added DbContext in DataAccess project
Added a console application project to the solution
Used NuGet to install EntityFramework 6 to the DataAccess and ConsoleApplication projects

The project runs fine and creates the database in the SQLEXPRESS server on my desktop. There was no connection string anywhere in the application. There is also no app.config file in the DataAccess project. The only app.config is in the console application project.
I even added a connection string to the console application's app.config and tried the different options with enable-migrations. But nothing seems to work.
Using Visual Studio 2017 15.5.4 Community Edition
Answer: Reading this SO post suggested that maybe some project types may not be compatible with EF 6 migrations. So, instead of using a class library project type of ".NET standard" for the DataAccess project, I tried using the ".NET framework" project type for the DataAccess class library project (where the DbContext is defined). Migrations worked fine as before.


SQL Server 2012 - SA account probe

Question: On one of my servers (Win 2012 R2), SQL Server 2012 is constantly under attack with the SA account being hit like 10 times per second with different passwords. I don't have an SA account but still I would like to stop this probing as its probably consuming resources. I keep checking the logs and blocking the offending IPs at firewall level manually, still I would like a better solution. SQL Server runs locally with IIS to serve its websites, I only need to connect to SQL Server remotely for database development with SSMS, so at first I thought setting up a VPN but not sure if this is going to play well with SSMS and other services like FTP. As in interim solution where can I stop SQL Server from being visible to the outside world at the firewall by disabling port 1433, or elsewhere? I can then enable/disable this when developing and perhaps just for my IP. Thanks.
Comment: You appear to be able to block IPs in the Windows firewall; I'm sure closing ports should also be available as an option, no?
Comment: I have closed the SQL port and that stopped all the probing by I have to remember to enable my IP in all the time (dynamic IP) for development. Isn't there a tool that looks at the windows log files and on those events that show a SQL probe, add the IPs to the firewall to block them automatically?
Comment: May be there is such a tool, but then 1) you may want to clarify what you ask in the question itself and 2) it's not a SQL Server problem; you may have better chance asking about it at [sf]
Comment: You could use a port forwarder and proxy to hit the dev box from the same ip. You could RDP in to that network to do work.  You can automate the IP settings and only have it off while you're working then have it turn back on.  You can set it up as part of something like a octopus/jenkins system like you do dev.  There's many options, do any of those work for you?
Answer: So the IIS on this server is intended to be externally accessible from your internal data network but the SQL Server instance on this same server is not meant to allow for external connections except for only through the web interfaces of your applications, correct?
If so, then is not adding an explicit rule in the Windows Firewall on this server to allow only the private IP address ranges to connect via local network on SQL Server ports not acceptable? I assume you trust your internal IP addresses on this port and don't suspect those as the authentication attempts with malicious intent?
Allow the [localhost IP] IIS apps to authenticate to SQL (may need to check site bindings, etc. and/or setup internal DNS pointers too).
On your external side, you should only be allowing the port 80 or 443 to port forward/NAT to the IIS server on those ports only and not all ports too it I would think -- stop at corporate firewall too I guess and only allow the web app ports to go to that server from the external interface with your firewall appliance proxies, etc.
Answer:
SQL Server runs locally with IIS to serve its websites

The main problem I see is having sql server and IIS running on the same server. IIS serves website and SQL Server should be on a different server and only allowed connection from IIS to SQLServer.
There are things that you can do to mitigate the problem:

Change SQL Server port away from default of 1433 - I prefer static port. (this requires restart of sql server). Check my answer here for more details.
Disable SQL Browser service and hide your sql server instance, so that attempts to find named or default instances is alleviated.
Configure your firewall to block/restrict IP ranges that you think are the source of attacks.
Rename SA to something unusual e.g. DoNotUseThisLogin and Disable it. Use windows authentication ONLY.
Run Microsoft SQL Server 2012 Best Practice Analyzer to fix anythings highlighted.
Make sure you uninstall any unneeded components and only the ones that are minimally needed are installed.
You can implement a poor man's solution LOGON Trigger to limit connection rights to sql server.
Comment: With SQL server on a different server I experience lag in web page responsiveness as it will have to request data further than locally, so its a no for me right now. I will try the port change away from the default, maybe that will help with minimal side effects, also the logon trigger script is a great idea and will test fully soon. For now, disabled the firewall inbound rule for SQL server and that's doing a great job with minimal inconvenience. Thanks.

SQL Server 2012 - SA account probe


Why is the water dissociation constant valid for acid/base solutions?

Question: The water dissociation constant was first defined with respect to dissociation of water into hydroxyl and hydronium ions. How then can one say that it is valid for an acidic solution, that is, even in an acidic solution the product of the concentrations of the hydronium and hydroxyl ions is $10^{-14}\ \mathrm{M}$?
Comment: That's the nature of chemical equilibrium. There is a reason why constant is defined as $\ce{[H+]\cdot[OH-]}$ and not some other way.
Answer: If Kw is written in terms of concentration (as opposed to activity), as [H+][OH-], it is only $10^{-14} M^2$ in the limit of zero ionic strength, but it is approximately correct in general.

image source
Answer: Acidity and alkalinity in aqueous solutions is based upon the autoionization of water:
$$\ce{HOH + HOH -> H3O+ + OH-}$$
For pure water, the following equation is valid:
$$[\ce{H3O+}] = [\ce{OH-}] = 1 \times 10^{-7}~\mathrm{M}$$
Thus, to calculate $K_\mathrm{w}$:
$$K_\mathrm{w} = [\ce{H3O+}][\ce{OH-}] = (10^{-7})(10^{-7}) = 10^{-14}$$
If a solution is acidic, then $[\ce{H3O+}]>[\ce{OH-}]$ and if it is alkaline $[\ce{H3O+}]<[\ce{OH-}]$. However, even if the concentrations are not equal the product of molar concentrations $[\ce{H3O+}][\ce{OH-}]$ will always be $10^{-14}$ at $25~\mathrm{^\circ C}$.


* Playtest feedback request* Puzzle 3

Question: You find the following four images (they are not in any particular order). Your solution is a street name (it will be well known to the players but might not to someone trying the puzzle here).
Comment: Is familiarity with any non-English language necessary to solve this?
Comment: Not really. Players will have to understand what the shapes and images they are looking at are but character maps, and google image searches are allowed so that should help.
Comment: I've identified most of the things in each image, but I have no idea how anyone's supposed to find out what that near-circle symbol is. It seems basically impossible to find if you don't already know what it is.
Comment: Gotcha, thanks for the feedback. That one actually isn't a symbol but it might combine with something else to form one. :) Hopefully that helps.
Comment: @Deusovi I took it to mean the ROT13(mra flzoby).
Answer: Partial answer: maybe solved?
The lower-right symbols are

 Gurmukhi numerals from 1 to 4. These give an order for the four images.

Using that,

 the symbols are: the two halves of an @ sign, the "om" symbol from Devanagari, and the Hangul character "ik". This spells out ATOMIC.

Using that,

 each of the four numbers given is close to the atomic mass of a particular element. These element symbols are B, O, Re, N, making Boren Street the answer? This street name exists, but isn't particularly common, and I haven't figured out what to do with the rest (so this may not be the answer).

 It's possible that the inverted IPA is supposed to clue something along the lines of "API" or "ELA". I'm not sure what the number 1 on a film reel(?) is supposed to be, though, and I don't see how the dolphin's tail and the one-way sign are particularly useful.
Comment: Well done! Indeed it's not a common name but the people solving this will be familiar with the name. For the second line (which you didn't need) ROT13(Gur frpbaq yvar fcryyf bhg "Jrvtug" nf vg tbrf jvgu gur svefg gb gryy gur cynlre gung gurl fubhyq hfr gur ngbzvp jrvtug. vgf "bar jnl" -1 nf vg vf n cubgb artngvir bs gur yrggre bar, gura n gnvy naq n artngvir vzntr bs na nyr. )

* Playtest feedback request* Puzzle 3


Can I get a new cracker?

Question: My cracker has been deleted or hidden. I don't have the software to unhide it. Is it possible to download a new cracker without restarting the whole game?
Answer: The Download center allows you to download a 1.0 Cracker to get you back on your feet.
Answer: You are not able to get it back unless you download one from the Download Center (https://legacy.hackerexperience.com/internet?ip=241.151.9.102) or you can go through the riddles/puzzles to get back up to that level; Or if you still have the money just research on the level one cracker (it's not the best way but it's another way for the rich and people who have a lot of time.)
Comment: You need a cracker to do the puzzles.
Comment: I'm late to reply to this, but you are correct. You need a cracker to do the puzzles. The Download Center provides one.

Can I get a new cracker?


How to set the command prompt font on XP?

Question: I need to set the font on the XP command prompt on a few machines so that it would correctly display Hebrew file names. The default font displays a lot of gibberish, so I'm pretty sure changing it will do the trick. Can anyone point me in the right direction?
Comment: -1 your question doesn't have much value because you didn't even comment about what font (if any) you found worked.
Answer: There are two steps to doing this. Firstly you need to set a font that supports hebrew charectors as an availible font for the command prompt. To do so, open regedit and browse to this registry key:
HKLM\Software\Microsoft\WindowsNT\CurrentVersion\Console\TrueTypeFont

In here you should see an entry of:
0 Lucida Console

You need to create a new string value, called 00, with a value of the name of the font you want to use. If you already have a 00 entry in their, use 000 and so on.
Once done, restart the machine. You should now be able to click on the upper left corner and your font list should now include the font you wish to use.
Comment: well ok though it helps to know what Font would work. Sadly the questioner didn't bother to comment on what. Of these http://i.imgur.com/VnL83PC.png  the only that work are dejavu and lucida(a default) and droid and consolas(maybe a default).    Miriam has hebrew characters and I think is monospaced, but isn't supported by cmd based on my test.
Answer: The following article describes how to add fonts to the command prompt dialog, though I haven't tested it.  The article also links to a Microsoft Knowledge base article on the requirements for command window fonts.
http://smallvoid.com/article/winnt-cmd-add-font.html
Answer: Apart from installing a font with Hebrew glyphs, I think you may also need to change the codepage, like by invoking chcp 65001 (65001 being CP_UTF8).
Note that when running chcp 65001 within a batch file, all subsequent lines in that batch file are somehow silently ignored. One can use the following instead:
chcp 65001 && your_command_here ...

(And like you may already understand: for Unicode support, one should not use "raster fonts".)
EDIT: in Super User's How to change the Windows console font?, user Leonardo provided a link to Why are console windows limited to Lucida Console and raster fonts? This article explains:

The console rendering model assumes each character fits neatly inside its fixed-sized cell. When a new character is written to a cell, the old cell is overprinted with the new character, but if the old character has overhang or underhang, those extra pixels are left behind since they "spilled over" the required cell and infected neighbor cells. Similarly, if a neighboring character "spilled over", those "spillover pixels" would get erased.

In other words: only a few fonts will actually render nicely in console windows.
Answer: In the command-prompt you can click on the upper-left corner icon to choose Properties.  In those screens is a Font choice but on my system it is limited to 2 fonts.
Comment: Same here... any idea on how to use fonts other than these?
Answer: While many of than answers will change the font, it might also be helpfult to be able to type in those filenames should you decide to do something with them.  For windows XP you need to install the MUI pack.  MUI packs are generally availalable to enterprise agreement customers


If someone's arm is cut off, how does that affect blood circulation throughout their body?

Question: Essentially what I'm asking is that if someone's arm is amputated, doesn't that cut off a significant part of their blood flow because the blood vessels that normally flowed up to the hand of the amputated arm and back can't anymore?  If it heals, does that mean the body has to grow more vessels to sort of complete the circuit again?  Does the body just compensate by putting more stress on the rest of the body's blood vessels?
Comment: please mention the source from  where you found the information that cut at one place affect circulation at rest-portion of the body. However not much answer but from very common sense it seems logical. If you have a pipeline for water at your home and the pipe leaks, the water pressure would fall, so you would get slower water. Also in case of that healing; certainly some new blood capillaries regenerate but when the hand is no more, I think there is no need to regenerate the long arteries and veins for hands. just 'sealing' wounds and make a close-circuit with capillaries seemingly enough
Comment: Is it in reference to surgical amputation?
Answer: If I understand your question correctly, you ask how does the body deals with released blood volume after the removal of part of blood vessels?
The simple answer is the body decreases the blood volume. Our body is able to alter blood volume significantly in response to different factors.
For example, take a look at this paper: Blood volume changes in normal pregnancy. It states that:

A healthy woman bearing a normal sized fetus, with an average birth weight of about 3.3 kg, will increase her plasma volume by an average of about 1250 ml, a little under 50% of the average non-pregnant volume for white European women of about 2600 ml.

So, after the arm cutting, an organism will decrease its blood volume. Although it will take some time, blood volume altering is more probable way than new vessels generation.
Answer: Amputation of a limb or more will cut off both the arteries and veins to and from that limb. The body will compensate by reducing the amount of the circulating blood in it in order to maintain normal blood pressure. The best analogy I can provide would be electrical circuits: In amputation you are removing a circuit that is connected as a parallel circuit, not as a series circuit, therefor there is no need to create new connection after amputation to allow the circuit to complete, you just need to block the loose ends (ligate the main artery and vein to the amputated limb).
Amputation does not lead to increased stress on the remaining part of the system, in fact it has the exact opposite effect. The heart as a pump becomes more efficient as the "piping system" is now shorter with less resistance, and people with cardiac failure report feeling improved cardiac symptoms after amputation, and those with high blood pressure require less medication to control their blood pressure. In fact, the functional efficiency of all other vital organs like the kidneys, pancreas and liver improve as a result of reduced body mass (they now need to service and detox less cells). If the person was diabetic, their requirements for external insulin reduce, and people who suffer kidney failure might no longer require dialysis as the remaining kidney function -although compromised- becomes sufficient to filter the smaller amount of blood which includes less -waste chemicals- due to reduced muscle and fat mass.
Comment: I'd like to see references for the core statements (blood amount is reduced in response to limb loss, and improved heart function after limb loss), but the main point is correct: our circulatory system consists of thousands of smaller parallel circuits that branch off the main vessels in the trunk. As soon as blood clotting has taken care of the actual leakage, the rest of the system goes back to stable.
Comment: Cardiac function improvement refers to the immediate improved efficiency of the heat as a pump following amputation, due to the reduction in the vascular tree this pump needs to service, while the cardiac muscle remains unchanged, and still at a high risk of further clots leading to future deterioration of cardiac function. Unfortunately I couldn't find references to support this statement, but if you ever meet a vascular amputee I expect you will be able to confirm that it is true.
Comment: You are absolutely right about the increased risk of cardiovascular complications following vascular amputations, but this is different from "improved cardiac function following amputation".Vascular amputees had narrowing in the main artery leading to the limb, and this is usually part of the systematic vascular problem. These people will continue to be at high risk of vascular complications in other organs following a vascular amputation, and statistically speaking, a vascular amputation is considered a predictive risk factor for further vascular problems in other organs.
Comment: There are limited references in peer reviewed journals in relation to this subject. Studies related to amputees are very limited due to this area of science being too specific as amputees represent a relatively a small percentage of the population. However, total blood volume is generally calculated based on the person's weight as the main predictor, and limb amputation clearly reduces weight leading to reduced circulating blood volume: https://reference.medscape.com/calculator/estimated-blood-volume https://www.medicalalgorithms.com/blood-volume-after-amputation
Comment: Fair point about blood volume. I was still wondering about the improved heart function though, and I haven't been able to find evidence for that. To the contrary, when looking at the risk of heart attacks, it seems patients who lost a limb due to peripheral vascular disease have an even increased risk, and patients with limb amputation for other reasons have no change in risk (https://jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-018-0400-0). For leg amputees, cardiovascular complications seem to be increased generally (https://academic.oup.com/qjmed/article/101/4/251/1544580).


sql mail and ssrs

Question: Is it possible to attach a report from SSRS as PDF and send using sql mail? the server is MSSQL 2000.
Answer: You would need to save the report to the file system (not sure if SSRS 2000 can do that) then pick it up with the SQL Mail job.
Failing that setup a .NET app to connect to the web method that SSRS exposes (this is based on SQL 2005, so hopefully it'll work in 2000) and create the PDF and have the .NET app save it.  Then have the next step of the job grab the file and email it out.
I take is SSRS 2000 doesn't support email report delivery?
Answer: Why not use email delivery built into SSRS? Underneath, this uses SQL Agent anyway.
All versions of SSRS support email delivery. Configuring email delivery for SQL 2000.
For PDF... when you set up the subscription you specify the render format. I can't test this bit, but I assume PDF is supported here because PDF is supported anyway.
BOL link: How to create an e-mail subscription
We've also tested URL Access to generate PDFs followed by using SSIS emailing as attachment to work around some corporate limitations.
Comment: Umm.....Duh......, needless to say I am new to SSRS.

sql mail and ssrs


How to write an interface to lichess for a millenium board using chesslink?

Question: I am aware of the python chess and chesslink mchess work but would like to attempt to interface it with lichess.org.  My purpose would be to play others on lichess using my Millenium board.
 The API's I've found for lichess seem to be for a chess engine interface rather than external hardware.  Any guidelines on where to find other similar work (like how DGT may do it)?
Answer: As you've seen, the Lichess API only allows bots to use the API functions that make moves in an ongoing game.  As far as I can tell, this is intentional; the API requires that anything that can generate moves in a game by some means other than human interaction on the Lichess site must be flagged as a bot.
Which means (again, as far as I can tell...), the only way to do what you want to do would be to create some kind of intermediary between the e-board and Lichess that actually mimics the actions a human would take during a game (such as simulating mouse clicking and movement on a game's web page).
I personally would not know where to start if I were trying to do this, and I also don't know if doing something like this would trip Lichess's anti-cheating detection in any way.  But it appears that this is what you'd have to do in order to play on Lichess using an e-board.


Out-of-the-box pool mining solution

Question: It is very hard to find an open source free solution to build a public mining pool.  Is there any pre-made, out-of-the-box solutions one can buy?
Answer: I would disagree that it is hard to find open source solutions, there are three pieces of software that need to be combined to create a mining pool.

bitcoind (or litecoind etc)
Pool software (pushpool or stratum)
Web front end (SimpleCoin, mmcFE, MPOS)

I am unaware of any commercial out-of-the-box solutions at this time.
Answer: You can try p2pool which is open source.

Out-of-the-box pool mining solution