Is complex life on a season-less, moonless planet, with two separate and distinct ecosystems possible?

Question: Is it possible for complex life to exist on a planet with no tilt and no moons, and be so close to its sun that the equator would be far too hot to cross on foot and still survive, and its poles far too cold to explore, and yet it would have two distinct habitable zones, or strips, if you will, (one on each hemisphere), between the equator and the poles? If this planet could hold liquid water in deep canyons and and support an oxygen-rich atmosphere, might it be possible that its northernmost habitable strip and its southernmost habitable strip could have evolved two completely different complex ecosystems, both of which evolved complex life, such as humans that never encountered one another, until say, the invention of the airplane and subsequent crossing of the equatorial region to the opposite hemisphere?
Comment: A planet without a tilt would mean that the poles would not change temperature, and thus there would be no seasons. Something to keep in mind
Comment: Like Australia,  or unique flora of volcanic islands.
Answer: Not quite what you're looking for in terms of the setup, but the end result is similar - Jinx, an egg-shaped planet.

The idea is that the shape of Jinx was fixed when it was in a close orbit to its primary, leading to tidal forces strong enough to produce this shape. Over time, tidal effects have caused Jinx to recede from its primary, while at the same time the planet has cooled and become more rigid, retaining its distorted shape.

The key in your case is that due to its odd shape, the equator ends up with extremely high atmospheric pressures.  This gives Jinx two "bands" of habitable latitudes, with the equator being uncrossable without higher technology.  Here's a crude illustration:

If you don't want it to be around a gas giant, you could say that it was distorted by a star and then retreated, or that it formed as part of a gas giant system and then was lost, ending up in orbit around the star instead.
Answer: To achieve a world such as this, the sun must have an extremely low luminosity, such as an old red dwarf star, possibly even a neutron star, and the world must be in an extremely close orbit around it.
The very low luminosity would mean that a matter of a few thousand kilometres would be sufficient to cause a significant difference in temperature, allowing the situation required with a very hot equator and very cold poles.
The fact that this world orbits such a star (that must once have been much larger) at such a close range would indicate that it would have to be a captured object.
Answer: I'm not sure you can have cold poles while not having winter and being close enough to the sun to produce the extremely hot equator you are looking for, but isolated habitable regions is certainly possible.
Life would probably not have evolved completely independently in the two zones. Seeds and small insects can quite easily be picked up by a storm and blown great distances before landing. Birds might be able to spread this way too, but anything larger will have had to develop independently.
If the habitable zones have similar ecological niches available, you can reasonably expect something to evolve to fill them in each location, a more extreme version of what happens with remote islands on Earth.
Humans are more problematic. Intelligent life may evolve in both places, but it is very unlikely to happen at the same time, especially if you are including civilization. That requires ending up within a few thousand years on a scale of billions - a one in a million chance.
To run into intelligent animals which could be taught civilization, the target widens to a million years or so but its still a thousand to one.
Answer: This is interesting. I would say that the less environmental fluctuation there is, the less evolution happens (or happens very, very slowly). Most likely you would get organisms which are hyper-adapted to their specific environment/climate and which could not survive on different one.


How to design squeak and creak sounds of metal objects?

Question: Are there valid guidelines to design squeak and creak sounds produced by metal objects?
Here are some examples:
Example 1
Example 2
Example 3
Answer: A violin bow on a cymbal can make some cool squeaky/creaky sounds.
Using a piezo disc taped to the cymbal as a transducer can help make it more metallic sounding than using a microphone, but either way is fun.
If you don't care about scratching the cymbal you can also experiment with scraping metal objects against it. Hardened metal (like a good screwdriver tip) can be nice and creaky.
I'm sure there are other ways, too..
Answer: Sound Design is a creative pursuit. Consequently the way to progress in Sound Design is to learn the common techniques involved, such as:

Sound Recording
Editing
Layering
Pitch and Tone manipulation
Audio Processing
Mixing
etc.

Once you are familiar with these techniques, begin to experiment with particular sounds and see what you come up with.
There are no other guidelines than this.
Answer: Talk to your local torsion testing laboratory record real metal


Ubuntu 12.10 Intel Ironlake Graphics Driver

Question: I'm running Ubuntu 12.10 and steam on my laptop. I need to install the Intel graphics driver. When I go into details on my system in says the graphics is unknown. Some Steam games will launch, I have had Splice, DEFCON and a few other small games working but when I launch Counter-Strike: Source or TF2 the audio plays but the screen is just black. Any help is really appreciated
Answer: I'm having the same issue issue with my Intel HD 3000 graphics. Eventually, I found out the Intel graphics don't support OpenGL 3.1 or the higher versions regarding the driver. Until something new is made or done, You kinda can't play those Steam games that require that graphics version to work on Intel HD graphics.


Nocturnal pack hunting animal that hoots like wind chimes - Massachusetts

Question: I have a question about something that happened on the conservation land just behind my house 3 or 4 years back, not far north of Boston.  For a couple of weeks, I occasionally heard some creature in the woods at night that had a call that sounded just like wind chimes. Then one night a pack of them assembled, chiming back and forth at each other in a manner consistent with baying, and brought down a screaming animal not far behind my neighbor's house, that stopped screaming quite abruptly.  The prey sounded about the size of a cat or a raccoon.  The wind chime hooters, I think were likely also a smallish animal. They seem to have moved on within a month or so.  Does anyone know what these are?  I've never been able to find any references for them. Thank you!
Comment: Did it sound anything like [this](https://youtu.be/YtsZoIe3Czk?t=20s)?
Comment: My cat got very upset when I played this.
Comment: For the past three days I have heard the sound you mean. Kinda. Like bamboo windchimes sound..right? I am concerned. Two days ago the sound was on three sides of me. I have never heard this sound...we got chickens 3 months ago..keeping my eye out for sure
Answer: I have no idea what "sounded like wind chimes" is supposed to mean.  No animal that I know of makes a metallic clinking sound.  The closest would be several frogs, but that doesn't fit at all with everything else you said.
Ignoring the useless description of the sound, everything else points to coyotes.  It would be helpful to be more specific than "not far north of Boston" so we can at least know the nature of the general surroundings (houses and pavement, open field, a large wooded area, etc), but coyotes are now all over New England, even in some urban areas.
Coyotes don't exactly congregate in "packs" like wolves do, more like family groups.  Several of them together is not unusual at all.  The screaming animal you mention was probably a neighborhood cat.  Cats usually scream loudly as a last resort, and coyotes are known to prey on house cats sometimes.
It is also consistant with coyotes that they stayed around for a month or so, then moved on, particularly if this was not late winter when they have pups in a den.
I live in Groton MA with woods all around the house.  We have a group of coyotes in the general area, and twice now their den has been on our property.  Mostly we hear them, especially when they howl back at trains honking at a nearby crossing.  I only see a coyote on our property maybe 2-4 times a year, but pick them up routinely on a trail camera in the woods.
Comment: Click on the word "This" in ShemSeger's comment, above.  They really do sound a bit like wind chimes.
Comment: Not sure what wind chimes you guys have hanging around your house - glad you aren't my neighbor.  I agree with the coyote assessment however - they make a variety of calls (I heard some weird stuff when one was separate from his pack and sat in my yard calling to the others all morning) plus they are the only animal I know of in the north east US that call to each other and would hunt in a group. The prey size sounds about right too.
Comment: Rabbits also have a pretty blood-curdling scream, as I can attest to from years of coyotes coming down the arroyo by my house to eat the fat grass-fed rabbits in the neighborhood.


In what episode of the anime does Natsu become a demon?

Question: Just like the title says: in what episode of the anime does Natsu become a demon (E.N.D)? I was wondering if that even happened in the anime or only in the manga?
Comment: Sadly it has'nt been revealed yet , the anime is on TARTAROS ARC and it manga it focus Zeref's planning to have war (spoiler) It has'nt been released Natsu becoming END but still it has a long way to go for that part and too early for Natsu becoming END (I'm curious though)
Comment: [Spoilers] Episode 308.
Answer: The current Anime Episode is shortly after the Tartaros Arc.
Right now it is unknown to Natsu that he has something to do with any Demons inside of him.
Answer: The last episode of the Tartaros arc is where we learn that Natsu is E.N.D. Zeref is holding the Book of E.N.D. at the end of Episode 265 when he pronounces Natsu's full name: Etherious Natsu Dragneel.

However, after this, the anime went to Fairy Tail Zero material, which relates the backstory for Mavis, Zeref, and others.
Answer: Put simple, Natsu has not become a demon yet in any form of media. It has been revealed that he is END in both the manga and anime, but Even in the manga he has not transformed. It may never happen.
Answer: In the manga Natsu turns into his demon form in chapter 500 and it is revealed that he is E.N.D after his older brother(Zeref) reveals his full name: Etherious Natsu Dragneel at the end of the Tartaros arc. Although his demon form has not been revealed in the anime and Natsu has no clue about what he truly is but it is highly anticipated that it will show up...
eventually.
Answer: I'm pretty sure that the show wouldn't end without Natsu finding out that he is not only E.N.D, but that he is Zeref's Brother who passed away 400 years ago when they were only little kids. One person that should be included (if the show digs deeper into Natsu's background,) is Larcade Dragneel. I'm not really sure what his connection is with Natsu, although it would be a nice addition to the show and it would keep things interesting.


Is there enough evidence of Sansa Stark turning against House Stark?

Question: I've always thought Sansa was a traitor to the House Stark. My memory is fading as the last time I read the book was when A Dance of Dragons was not available yet. Is there enough evidence of her falling to the Lannisters?
Answer: At the beginning of the story, Sansa is extremely naive - she fully believes in noble kings and princes who are wise and good, and handsome white knights in shining armor. Getting to live in King's Landing and marrying Joffrey is a dream come true to her. And of course, the whole bigoted society of Westeros reinforces all that. When Joffrey acts dishonest, cruel and vindictive in the incident with Arya and Mycah, Sansa is faced with cognitive dissonance - what she has seen conflicts with deeply held beliefs. She reacts as many do and twists the facts to match her beliefs, shifting the blame on Arya.
Part of that belief system is that Joffrey, as her king and future husband, deserves her full loyalty. Of course her family deserves it as well, but conflicts of loyalty with lethal consequences are not part of her fairy tale education, so when her father tells her they'll go back to Winterfell and thus threatens her fairy tale, she decides (somewhat self-servingly) to betray her father's actions, without realizing what it will lead to.
Technically, that makes her a traitor. But from a purely legal standpoint it is probably actually true that loyalty to the king trumps loyalty to the family, even if the king is a sadistic, spoiled bastard. And from a moral standpoint, she couldn't possibly know just how bad the consequences of her actions would turn out, so she cannot be given full responsibility for them.
The next tragic thing she does is incriminate her father publically, apparently sealing his fate. But this happens under pressure from Cersei, who plays the "loyalty to the king" card unrelentingly, while at the same time promising mercy. Sansa has realized at this point that there's something wrong with this fairy tale, but she has little chance against Cersei, and realistically, the Lannisters would have killed Ned Stark anyway - Sansa just allows them to do it in a more legitimate-seeming way.
Joffrey's decision to have her father executed on a whim after she pleaded for mercy pretty much kills her belief in fairy tales and forces her to grow up very quickly (sidenote: she also soon afterwards has her first period, late for her age - probably symbolic).
Afterwards, she keeps professing her loyalty and love for Joffrey, and calling her father a traitor. But by this time, it's purely an act, necessary to survive. She knows it, Cersei knows it, but is perfectly willing to accept fake loyalty to keep up appearances. Joffrey probably doesn't know - he's not just cruel and vindictive, but also stupid.
Sansa is undeniably the character who develops most over the course of the series.
Comment: "realistically, the Lannisters would have killed Ned Stark anyway" - unlikely. They wanted to send him to the wall, as he his honor would keep him there. That would avoid large scale trouble with the North.
Comment: @thegrinner: I'm pretty sure Ned would have had a fatal accident (or encounter with bandits) on the way to the wall, just to makes sure he causes no more problems.
Comment: @MichaelBorgwardt, such an accident would have been enough to trigger the same war with the North due to accusations of foul play. Especially since Sansa and Arya would still have been hostages at the time. So it was very necessary to keep him alive long enough to take the black, after which anything is game.
Comment: That's definitely possible. My understanding has been that no one involved wanted a conflict *yet*, and sending him to the wall would delay it while protecting Cersei and her brood.
Answer: Has Sansa Stark contributed to the near destruction of her House?
Yes. Her most damning actions were unwittingly revealing her father's plans after Robert's death, and her publicly denouncing her father as a traitor to King Joffrey.
So she's a traitor to House Stark?
Not necessarily. Her first action was the action of a conflicted teenager who was not given all the facts. All she knew was that her father (for some undisclosed reason) was about to destroy her life and dreams. The second act she was manipulated into doing, believing that it was the only way to save her father from death.
Is that all that's against Sansa?
Narrative wise, the fact that she is the only (surviving) Stark with no Direwolf, has made many readers categorize her as the least Starky of the Stark children. Paired with her POVs in A Feast for Crows where she ...

 ... stops calling herself Sansa Stark and begins taking the persona of Alayne Stone ...

... has only served to further establish this break from the Starks.
Answer: There definitely is not enough information to surmise that Sansa has turned against House Stark. Be it to the Lannisters or otherwise.
Here is what George R.R. Martin has to say about the whole beheading of Ned Stark incident and Sansa's involvement:

REGARDING SANSA
  Your question re Sansa...
  The way I see it, it is not a case of all or nothing. No single person is to blame for Ned's downfall. Sansa played a role, certainly, but it would be unfair to put all the blame on her. But it would also be unfair to exonerate her. She was not privy to all of Ned's plans regarding Stannis, the gold cloaks, etc... but she knew more than just that her father planned to spirit her and Arya away from King's Landing. She knew when they were to leave, on what ship, how many men would be in their escort, who would have the command, where Arya was that morning, etc... all of which was useful to Cersei in planning and timing her move.
  Ned's talk with Littlefinger was certainly a turning point, though I am not sure I would call it =the= turning point. There were other crucial decisions that could easily have changed all had they gone differently. You mention Ned's refusal of Renly, which was equally critical. And there is Varys to consider, as well as the minor but crucial player everyone forgets -- Janos Slynt, who might have chosen just to do his duty instead of selling the gold cloaks to the highest bidder.So... all in all, I suppose my answer would be that there is no single villain in the piece who caused it all, but rather a good half dozen players whose actions were all in part responsible for what happened.Hope that helps.-http://www.westeros.org/Citadel/SSM/Entry/1017.

During her time in The Eyrie Sansa builds a snow sculpture of Winterfell signifying her deep longing for her place.
Answer: Of course she wasn't a traitor to the Starks! Once her father had been executed she was all alone in Kings Landing and just a pawn in the political power struggles. Her later behaviour with respect to her aunt was perhaps less honourable - although Lysa was never a Stark of course.
Comment: "Lysa was never a Stark of course"...only stark raving mad.
Answer: In my opinion, Sansa has merely been the pawn in a political game she does not have the wits or stomach to bear. Without a doubt she contributed to the demise of her family. In fact, I would say it is this reason I despised her so much in CoK and SoS.
But I doubt she ever sought to betray her family. Her decisions at the end of GoT were mostly based off misinformation fed to her by the Lannisters, or her clinging to her girlish fantasies of knights, kings, and highborn ladies. But I think it's clear to everybody that after the first novel, she has very little love for the Lannisters, and especially Joffrey.
Answer: Can a 12-year-old girl be a traitor?  She certainly wasn't too bright in "A Game of Thrones", and she was easily manipulated by Sersei to tell her what she knew about her father's plans.
Answer: In the first book she is a typical love-stricken teen with NO clue about the "real" world other that her fantasy fairytale books about noble knights and kings and other such rubbish. So her view of the world is colored as such.
She learns the really HARD and public* way how the world is and helps in her small ways.
Then she grows and figures out what is needed to protect herself. By going along with Littlefingers she makes sure to live on and maybe get back to her home by the end of it all.
So no she is not a traitor to house Stark. She is just a hot headed teen that did the same any other petulant/pouty teen has ever done since the beginning of time.

Beating, humiliation in public with her clothes torn off etc. Then there is also the matter of her refusing to bow down at the wedding for the cloak ceremony. Feisty and could have gotten her in trouble
Answer: Sansa will turn against her family. I'm pretty sure about it. Since the beginning of Season 8, we always caught Sansa talking/planning something with Lord Yohn Royce of the Knight of Vale.
The first was in the Winterfell corridor when they are interrupted by Tyrion, when Sansa told Tyrion, "I thought you're the smartest man".
And the other scene where they are interrupted by no less than Dany, "how about the North" scene. We don't know what they are planning but (correct me if I'm wrong) during the Battle for Winterfell with the Night King, the entire Knight of Vale/House Arryn went Missing In Action.
Comment: Hi there. While this may or may not be true in the _show_, the question being tagged with the ASOIAF tag would indicate the asker is rather looking for books-based answers; additional info from the show wouldn't be inappropriate, but I recommend you [edit] your answer to include quotes from the books supporting your assertions.


What is an "ashcan" release?

Question: What are "ashcans"? What are their purpose? Where does the name come from?
Answer: According to this:

I'm pretty sure that I understand what an Ash-Can is: It's a text that comes implicitly (and maybe explicitly) packaged with a disclaimer ... "contents are sold as-is, no guarantee of quality is implied, nor should any be inferred."

And According to wikipedia:

An ashcan copy is a term that originated in the Golden Age of Comic Books, meant to describe a publication produced solely for legal purposes (such as trademark), which was not normally intended for distribution.1
The word ashcan is an older synonym for wastebasket, trashcan, or other garbage receptacle. The implication is that the printed material will go straight from the printer to the trash, which was often the case. Ashcan editions frequently contained unlettered stories, unfinished art or even just whatever wastepaper had been conveniently available at the time. Their purpose was simply to justify the publisher's claim to a title, thereby preventing a competitor from publishing a similar title. Ashcans were also produced to demonstrate the publications to potential advertisers.

According to this blog's usage:

This is a game created to occupy the niche of story games concerning tensions in the relationship of a husband and wife. It's still in ashcan form and not its final form

Therefore, an ashcan release is one done as an initial, unpolished release designed to satisfy certain IP elements and, if sold at conventions, serve in many ways as a paid-for alpha test. A synonym would be "pre-release edition." The important aspect is that it is legally published, but not designed for wide consumption. The name comes from, as per wikipedia, the comics publishing industry.
Comment: The final paragraph is, I think, a good summary of how the term is used in roleplaying games.
Answer: (This is all based on reading about ashcans on a variety of indie RPG sites a year or two ago. I have purchased a few.)
The word "ashcan" comes from the comic book industry.  In recent usage in the comic book industry it tends to mean a smaller format comic (for varying meanings of "smaller") used as a freebie to try and hook new readers.
In the indie RPG scene, an ashcan is a sort of pre-release, a weird sort of public beta-test.  A designer might not feel their game is done or has uncertainty.  The designer wants feedback from a wider group of people.  This would normally be done by playtesting, but: the designer may have exhausted his playtesting pool, the designer may want opinions from "normal" gamers who wouldn't normally engage in playtesting.
Generally speaking an ashcan looks "finished," frequently with production quality comparable to the final product.
By and large you pay for an ashcan RPGs.  While this limits your player base, the people who purchase it will almost certainly be more invested.  The problem with, say, a free online release is that you'll get lots of downloads from people who will never play it.  They might offer feedback, but the designer wants feedback from actual play, not feedback based on just reading the rules.  If you've spent a few bucks on the game, you're presumably genuinely interested.  You're more likely to seek out a group, to try it repeatedly, and to be interested in providing serious feedback.
Finally, many ashcans come with a discount on the final game as a sort of thank you.
Answer: There also is/was a group called the Ashcan Front, that is/was using the medium in a very particular way as part of the roleplaying game development process. I think it is sort of dormant now but I don't really know. Anyway, that's a link to their FAQ.
The notion was that only people invested in a project would actually buy an ashcan, which is expressly unfinished and in development and full of questions, and that they would become part of a playtesting conversation that would improve the finished game.
Comment: I think that momentum is moving, these days, over to the kickstarter methodology.
Answer: In games prior to the 1990's revolution in publishing technologies, it usually meant a self-published version intended to be used to shop it around at cons to both a select group of playtesters, and to the big companies in hope of a "real release." It also would have two copies sent to the Library of Congress to establish formal copyright protections.
Some ashcan versions were near-professional layout quality, others simply optically typeset text, and were not in distribution networks. Several games mention shopping around the ashcans prior to being sold to a major company.
Given that many printing houses in those days required a minimum order of at least a hundred copies for a bound volume of any kind, it was common for such versions to be sold via mail, convention, or personal contact.
The term was often synonymous in use with "low quality cheap printing", as many were printed on the cheapest set of options the printing house would allow. The few examples I've seen of this mode were hand-typed mimeograph master dittoed (run off) on recycled unbleached high-acid newsprint, and used for playtest.

What is an "ashcan" release?


What is the stock price expectation?

Question: The Hull textbook (and accompanying technical note) says that the expected stock price $\mathbb{E}[S_T]=S_0 \exp(\mu T)$. However, the answers to a British actuarial examination (Q4 for September 2018) require it to be $S_0 \exp (\mu T +\frac{\sigma^2}{2}T)$. Why don't these values agree?
Comment: The second link you gave is to a downloaded file in your local directory so no one else can access it
Comment: Sorry, corrected.
Answer: In Hull's textbook, the stock price dynamics is lognormal: $S_T = S_0 \exp(\mu T - \frac{1}{2}\sigma^2T  + \sigma W_T)$, where $W_t$ is a standard brownian motion. And so the mean of this is the mean of a lognormal random variable with the log mean as $\ln S_0 + \mu T - \frac{1}{2}\sigma^2T$ and the log standard deviation as $\sigma \sqrt{T}$, and so the mean is (link to info on log-normal mean), $S_0\exp(\mu T)$.
In the exam, the stock price dynamics is also lognormal, but now there is no mean term involving $\sigma$, so $S_T = S_0 \exp(\mu T  + \sigma W_T)$. This is since the question is saying that there is, according to the wikipedia (and also standard) notation, a $\mu$ parameter and a $\sigma$ parameter, and so the $\mu$ value is as given. So the mean of this log normal random variable is $S_0\exp(\mu T+ \frac{1}{2}\sigma^2T)$.
So the two results actually do not contradict. They are different answers but neither is 'wrong', although the Hull result is the typical one you will see all over finance textbooks. The actuarial exam result is just a particular case of a log-normal dynamics for the stock price that they decided to use.
Comment: Sorry, I don't follow how this is a matter of notation? $\exp$ means $\exp$, and $exp(\mu +\sigma _)$ is patently different from $exp(\mu -\frac{1}{2}\sigma^2 T+\sigma _)$.
Comment: The stock price dynamics in hull and the actuarial question are different. So the answers are different. I can make a new stock price dynamics that say the stock price should be constant, so under those dynamics that expected future value is the same as the present value. So under different dynamics, the expected value is different.
Comment: The indication of different dynamics in the actuarial exam is that they give the $\mu$ term explicitly for a log  normal random variable, so the log mean does not involve $\sigma$
Comment: But the textbook gives $\sigma$ explicitly too, and defines it as "Volatility of the stock price per year". It also quotes the formula in a section (15.1) called "Lognormal property of stock prices", while the exam says "prices of both stocks are assumed to follow the lognormal model". I don't see any difference here.
Comment: the $\sigma$ term is the stock price vol. in both the Hull textbook and the exam. The difference is that the stock price dynamics in the Hull textbook includes the $-0.5 \sigma^2$ term while the exam does not. There are many types of possible log-normal models that can be used, but in this particular case, the difference is whatever I wrote above. I understand your confusion as to why the exam decided not to include it, but I think the point of the question was to just show that you know what a log-normal random variable is so as long as you can work with them, your understanding is solid.
Answer: Let's focus on the technical note, but let's change the symbols for easy comparison. The note has two parts:
Firstly, if we assume that the stock price is log normal with the following parameters:
$S_t \sim \mathrm{LN}\left(\ln S_0+\mu t,\sigma^2 t\right)$
then by definition, its log is normally distributed:
$\ln S_t \sim \mathrm{N}\left(\ln S_0+\mu t,\sigma^2 t\right)$
We can write it in terms of standard normal:
$\ln S_t=\ln S_0+\mu t+\sigma \sqrt{t} Z$
which means:
$S_t=S_0 e^{\mu t+\sigma \sqrt{t} Z}$
The mean of the above variable is indeed:
$E\left[S_t \right]=S_0 e^{E \left[ {\mu t+\sigma \sqrt{t} Z}\right]+ 0.5 V\left[ {\mu t+\sigma \sqrt{t} Z}\right]}=S_0 e^{\mu t+0.5\sigma^2 t}$
This is the equivalent of $e^{m+s^2/2}$ in the Hull's technical note (just after equation 1).
On the other hand, if we we assume that the stock price follows GBM:
$\frac{dS_t}{S_t}=\mu dt + \sigma dW_t$
Then by applying ito's lemma, we know that this means:
$d \ln S_t=\mu dt+\sigma dW_t-\frac{1}{2}\sigma^2 dt$
$\ln S_t=\ln S_0+\mu t+\sigma W_t-\frac{1}{2}\sigma^2 t$
or in terms of standard normal (after rearrangement):
$\ln S_t=\ln S_0+\left(\mu-\frac{1}{2}\sigma^2\right) t+\sigma \sqrt{t}Z$
$S_t=S_0 e^{\left(\mu-\frac{1}{2}\sigma^2\right) t+\sigma \sqrt{t}Z}$
So it is log normal but with mean $\ln S_0+\left(\mu-\frac{1}{2}\sigma^2\right) t$ and variance $\sigma^2t$. And the Hull's technical note gives these formulae immediately after the equation $e^{m+s^2/2}$ that I referenced above.  The note references the text, which I believe is equation 13.3 in Hull's textbook (7th Edition). We can thus calculate its expected value as follows:
$E\left[S_t \right]=S_0 e^{E \left[ {\left(\mu-0.5 \sigma^2\right) t+\sigma \sqrt{t} Z}\right]+ 0.5 V\left[ {\left(\mu-0.5\sigma^2\right) t+\sigma \sqrt{t} Z}\right]}=S_0e^{\left(\mu-0.5\sigma^2\right) t+0.5\sigma^2 t}=S_0 e^{\mu t}$
Now to the exam terminology: It seems like the exam is using log normal model with drift $\mu$ to mean lognormal distribution with mean $\mu$.
Re-comment, the 1D-marginal distribution of the GBM process is indeed log normal, but the tricky part is the connection between the drift, and the mean. If we represent the GBM with drift  $\mu t$ and variance $\sigma^2 t$ by $\mathrm{GBM} \left(\mu t, \sigma^2 t\right)$,then the process value at time t, $S_t$ given its current value, $S_0=1$, has $\mathrm{LN} \left(\mu t-\frac{1}{2}\sigma^2t, \sigma^2 t \right)$.
For path-dependent options, if you were to use the probability distribution approach, you will need the joint distribution of the process values at different times. The joint distribution for most pay-offs will not be available in tractable form. Though for some path-dependent options, e.g., geometric average, the joint distribution is easy to use because the joint distribution is again log-normal. So the best would be to use a numerical method: simulate the process values under the risk neutral measure, or use PDE based approach.
Comment: It was my understanding all along that GBM and lognormal model are one and the same thing. Textbooks, including Hull, simply mention them all in one go. Is this not the case?
Comment: Also which one is "correct"? If I want to price a path-dependent option by simulating paths, which one do I discretize to do it?
Comment: I have added further details in the answer. Hope it makes sense!

What is the stock price expectation?


Music Player won't detect music on USB. Galaxy S7

Question: For some strange reason, my media player (I have tried MediaMonkey and Google Play Music) won't detect my music on my new USB. I can play music when I select the music file from the file explorer, but the music won't show up in either music player. I have checked to make sure there weren't any .nomedia files, and I selected the USB as the storage device in both MediaMonkey and Google Play Music. I refreshed and cleared caches, but none of these things help. And yes, the music files are supported by the players (I have both .mp3 and .flacs, niether show). Also, the files work fine on my PC, so I know they aren't corrupted or anything like that. I have also restarted my phone several times.
Phone: Samsung Galaxy S7
OS: Android 7.0
Comment: Possible duplicate. Check here. The answer comments indicate that play music runs of media server. Which will scan your Internal storage and SD card but not your usb stick connected through the OTG. https://android.stackexchange.com/q/125290/145490
Answer: Okay, so I just ended up buying Poweramp. It didn't have any issues reading the files off the USB. Sadly this cost me an extra 4$, but I was sick of trying to get Google Play to read the files properly.


How can I create "evented" it tests in mocha

Question: I've written a series of tests in mocha for a node.js client/server application that uses UDP to send messages between the client and server.
My tests are mainly on the 'client side', treating the server as a block box and validating the responses from the server. The problem is that some of the "conversations" span multiple message send and receive events, sometimes going up to the dozens of seconds. It seems bizarre to have a 1,000 line test script with only one huge call to it at the top - I want to run multiple tests during the "conversation". I want more granularity in which specific parts of the test fail if it does fail (e.g. the first 2 responses from the server were fine but the 3rd was malformed), but the initial tests pass.
I've looked in to nesting the calls to it (doesn't seem to work) and most recently separating the calls to it in separate steps, with each step representing the sending or receipt of one message at the client side.
This approach doesn't seem to work because mocha terminates the node application after the very first step, never waiting for the socket to receive more responses from the server and complete the rest of the steps.
How can I create "evented" it calls in mocha?
The first would be called at the start of the test, then each successive it would only be called after receiving a response from the server. I'm looking for any solution that gives me the granularity on tests without having to write enormous functions in my it call that include dozens of messages between client and server. It's also not ok to attempt validating responses from the server outside of the context of a conversation where many messages have been sent and received before hand, because those messages determine the validity of the server response.
See a sample implementation that I created at https://gist.github.com/4490219. You can see the result is that the first test passes but the second is never executed even though the socket is clearly still open and waiting for requests from the server.
(P.S. apologies for the text formatting of the gist - I couldn't seem to select Javascript as a language type when creating it)
(P.P.S. I really don't want to have to use a series of setTimeout calls at the start of each step to make mocha think it has to wait).
Answer: The solution is to use a combination of nested its (which actually can be achieved if you use a describe between each nested it) and using a registration it with long timeout who's done is only called when a response arrives from the server.
For future googlers I created another gist to show the solution for this problem.
https://gist.github.com/Trindaz/4490646


changing keyboard layout on a Thai-laptop - into German

Question: I would like to get rid of win8 and install ubuntu on my new Laptop. There is one question I have regarding the Keyboard. I bought this Laptop in Thailand and the keyboard is Thai/American. For me it is necessary to change the Keyboard layout into German layout and switch between Thai and German. Is this possible with ubuntu?
Thanks a lot...
Elke
Answer: This should be possible, at the install you are asked wich keyboard layouts
you want to use,or you go into the system setting click on keybord at the bottom of the window there is a button saying keyboard layout or likewise click it, in this new window at the bottomthere is a plus sign if you click it you can select additional layouts.
If there is more than one keyboard layout selected in thesettings then a little keyboard symbol appears in the upper right of your screen, you can easily switch layouts at any moment even if you are not logged in.


Car won't start, dies after jump

Question: I have a 2007 Ford Mustang, 6 cylinder. A few hours after I drove it, the battery was completely dead. It can start with a jump, but if left to idle the engine stops soon after the cables are removed. I used a multimeter to check the battery, and when the engine is pushed to 2000 RPM, the battery jumps from 12V to 14V(pretty sure that means the alternator works). But once the engine is left to idle, it dies and needs another jump. Any help would be appreciated, thanks.
Comment: What is the voltage of the battery when the car isn't running? If it's low, try to recharge the battery and see what it will charge to.
Answer: You can have a good alternator and still not charge the batteries if the connections are corroded in anyway or a battery clamp is loose or cracked. Also check the fusible links there should be one in line between the alternator to starter to battery circuit but if its pumping out 14 volts at 2000 rpm and wont idle for long afterwords then i suspect the voltage regulator in the alternator. To check this connect a voltmeter positive to the output post on the alternator and the voltmeter negative to ground, rev the engine up and down and watch the voltage output , if it fluctuates all over and intermittently then the voltage reg is the issue. Check the battery voltage at engine stop and if its the same voltage at idle then its the voltage reg or some other issue inside the alternator.
Answer: Normally if alternator is good, car won't die even without battery. I suspect alternator. I suggest you to buy a battery charger and charge battery and buy a Solar BA7 tester to test how many CCA are left in your battery. After eliminating battery problem, go ahead and buy an alternator.

Car won't start, dies after jump


How do I get private key from Bitcoin Wallet for Android

Question: I had BTC in the Bitcoin Wallet during the hard fork and would like to get my bitcoin cash. I moved all the BTC out of the wallet before bitcoin gold happened.
Answer: Export it with an export option or derive it from your word seed using a website or other tool.
I'd need more specific information to say more than that.


How to set restriction list to hide everything including comments and activities?

Question: If you put someone to restriction list, this user doesn't see your comments on your wall. That's one of the expected behaviors. But if you comment an entry in a page or write into the wall of a friend, this user still sees these entries. I want him to not see anything. I can't find any possibility to do that? Any ideas?
Answer: Blocking is the only way you can truly not let someone see your comments.
I deleted my account and started a new one because I did not want to "block" any friends.
I selected a few dear friends and made a comment on a friend's thread. Others who I thought could no longer see and reply to my comments did and were able. Ugh. So, yes you might as well block!
I did restrict my settings to only friends in my new account, but it does not apply once you comment on your friend's post. Their friends can see your comment which might be someone you are trying to avoid.
Answer: If you comment on a page then that is public (except for any geographic or age restrictions set by the page admin) and even non-friends can see it.  If you post on your wall/timeline then you control who can see it; if you post to Public then even those on your Restricted list will see it.  If you write on another person's wall/timeline then they control who can see that; the best you could do is to ask the other person if they wouldn't mind restricting those to Friends only (or if the person you are restricting is also their friend and they are not making the posts Public then you could ask them to instead exclude that person).
If you add someone to the Restricted list they will still see be able to see anything that is Public.  It is a way to be Facebook friends with someone without actually allowing them to see anything more than they would be able to see if they were not friends.
If you want them to see even less than what a non-friend can see then block them instead.  From their profile click on the gear and then Report/Block... and choose the Block option.  In that case you will no longer be friends with the person and they will no longer be able to see or like or comment on any posts or comments of yours on pages or the walls of other people, even if they are public, using their account.  In fact they will not be able to view your profile at all and you will not be able to view theirs.
Of course, if the posts are public then they would be able to see them using another account.
It sounds like you may not mind if they can see Public posts, but you just don't want those sent to their News Feed automatically.  However they control which information they want to see in their News Feed, out of the information that they are able to see.  By default, most posts and comments from friends to a page or wall that are visible to the person will appear in their News Feed, although they have the option to not show posts or Comments and Likes from you if they choose.  Even if they only sent you a friend request and you have ignored it, they will still see Public posts by you in their News Feed unless they turn them off.  By default these Public posts can also be seen by going to your profile.  If they are public then they will be difficult to hide.
Comment: Ok, that means it is not possible to keep him as Facebook friend without blocking him and hide "public" messages from him at the same time.


What is the call when a runner misses 2nd base on a 1st to 3rd and a dead ball call?

Question: runner on 1st. ball is hit to outfield. runner advances to 3rd missing 2nd base. the throw coming in to 3rd base goes into dugout. What is the proper call?
Answer: The runner would be awarded home plate on the overthrow, however, the runner would be out on appeal (if the fielding team appeals) for missing second base. The runner could return and touch second base on the dead ball before touching 3rd and home, in order. But once the runner touches 3rd base, if they missed 2nd then they would be out on appeal. If the fielding team does not appeal, then the runner would score a run. Here are the relevant MLB rules:

Rule 5.09(c)(1) Comment (Rule 7.10(a) Comment): "Retouch," in this rule, means to tag up and start from a contact with the base after the ball is caught. A base.
(2)  With the ball in play, while advancing or returning to a base, he fails to touch each base in order before he, or a missed base, is tagged;
APPROVED RULING: (A) No runner may return to touch a missed base after a following runner has scored. (B) When the ball is dead, no runner may return to touch a missed base or one he has left after he has advanced to and touched a base beyond the missed base.
Rule 5.09(c)(2) Comment (Rule 7.10(b) Comment):
PLAY—(A) Batter hits ball out of park or ground rule double and misses first base (ball is dead)—he may return to first base to correct his mistake before he touches second but if he touches second he may not return to first and if defensive team appeals he is declared out at first.
PLAY—(B) Batter hits ball to shortstop who throws wild into stand (ball is dead)—batter-runner misses first base but is awarded second base on the overthrow. Even though the umpire has awarded the runner second base on the overthrow, the runner must touch first base before he proceeds to second base.
These are appeal plays.
Answer: What would happen is each player offensive player would get 2 bases from where they were at the start of the play. ie: The batter would advance to second base.
According to SportsRec.com and the official MLB rulebook,

If the ball gets by the first baseman and skips out of play, the umpire will place the batter at second base. The rule is that when the defensive team puts the ball out of play, the batter will get two bases from the base he was at when the play started. Because the batter started the play at home, two bases would put him at second base. It doesn't matter that he was just a few feet from the base when it went out of play. He is entitled to second base and that's it.

This is proof that inside the dugout is out of play from baseballrulesacademy.com, verified with the official MLB rulebook.

The lip of the dugout is considered in play but the steps going down to the dugout and the floor of the dugout is dead ball area. If the fielder does not have both feet on the playing field at the time of the catch, it is not a catch.

Therefore, both of these concepts apply, and since the dugout is out of bounds, both of the runners would advance 2 bases. It would not matter that he did not touch second base, he would advance to third base, but if he had touched 2nd base before the ball was thrown out of play, then he would be awarded 2 bases, he would go to home base.


How to deploy ASP.Net MVC 5 to IIS 8 running Windows Server 2012

Question: I have developed serveral MVC 3, 4, 5 applications and have formerly deployed them via Visual Studio to a hosting provider. Never had a problem with that, everything have always worked. Now I have to deploy a MVC 5 application to a server in the company. I do the same thing as Always in Visual Studio, which means setting up a publishing profile, and then click Publish. The files are copied, and everything gets to the server, but do I not have to do anything in IIS, like Add Website or something? It doesn't work anyway after the VS publishing.
Answer: If you're deploying to the default web site in IIS you can safely publish to the default website's directory and be up and running.
However, if you're deploying an ASP.NET MVC site to a subdirectory of the default site, or to a new directory on the server, you will need to create a new web site, or convert the subdirectory (when publishing under the default site) to an application.
If this is your first time setting up a site on IIS, Microsoft has documentation on the steps to follow in the learn section of ASP.NET.
Comment: No, I'm deploying to its own site. I'm using ftp through Visual Studio.
Comment: Then you'll need to create a new site in IIS, if you haven't already. The documentation linked to in the answer should help you with that, if needed.


"If it hadn't been for the rock, the ship wouldn't have gone aground"

Question:
If it hadn't been for the rock, the ship wouldn't have gone aground.

What does this idiom mean, exactly?
From The Economist.
Answer: It's a sarcastic way of describing the unjustified shifting of blame. It basically suggests that it's not the captain's fault that the ship went aground, it's the rock's fault for being there.
Answer:
"if it hadn't been for the rock, the ship wouldn't have gone aground"

Blames the inanimate stationary rock for a ship running aground.  The implication is that the ship was poorly navigated, thus crashing into said rock however those in charge of the ship are placing the blame on the rock.
While the rock sunk the ship, avoiding this rock would only have bought a temporary reprieve as the disastrous management would almost certainly have found another rock to crash into.
Answer: There was a foreseeable obstacle.  But people without foresight are saying things would have been fine if there were no obstacle.
In the literal case, the foreseeable obstacle is the rock, and the people without foresight are the helmsman/captain/owner/etc.
In the figurative case, the Economist's MP source is arguing that the foreseeable obstacle is the economic crash (all booms end) and the  people without foresight are certain members of Labour.

"If it hadn’t been for the rock, the ship wouldn’t have gone aground"


MTG Conspiracy cards allowed in modern

Question: So I always thought that the Conspiracy set was allowed in Modern Format but I recently discovered that there are 65 cards that are not allowed. Can any give me a list or a link for a list of the cards that are or are not allowed in Modern play?
Answer: Cards from Conspiracy are not legal in Modern unless they were already printed in a Modern legal set. There were 65 new cards in that set, 52 are legal in Legacy and Vintage the remaining 13 are not legal in any Constructed format. The 13 that aren't legal are the ones with the Conspiracy type.
The only things that add new cards to the Modern card pool are sets that are Standard legal. Supplementary sets like Conspiracy, Commander, or Planechase do not, new cards from those sets are only legal in Legacy and Vintage.
Comment: This is no longer entirely correct. The Modern Horizons sets were never standard legal, but were made legal directly into Modern.
Comment: For a visual list of the 100 CNS cards that are modern legal you can head over here: https://scryfall.com/search?as=gridℴ=name&q=f%3Amodern+e%3Acns
Answer: The modern legal sets are as follows.
Core sets from 8th Edition on wards. This includes

8th Edition
9th Edition
10th Edition
Magic 2010
Magic 2011
Magic 2012
Magic 2013
Magic 2014
Magic 2015
Magic Origins

The following blocks are also part of the modern format.

Mirrodin Block (Mirrodin, Fifth Dawn and Darksteel.)
Kamigawa Block (Champions, Betrayers and Saviors of Kamigawa.)
Ravnica Block (Ravnica: City of Guilds, Guildpact and Dissension.)
Time Spiral Block (Time Spiral, Planar Chaos and Future Sight.)
Lorwyn Block (Lorwyn and Morningtide)
Shadowmoor Block (Shadowmoor and Eventide.)
Shard of Alara Block (Shards of Alara, Conflux and Alara Reborn)
Zendikar Block (Zendikar and Worldwake.)
Rise of the Eldrazi Block (Stand Alone.)
Scars of Mirrodin Block (Scars of Mirrodin, Mirrodin Besieged and New Phyrexia.)
Innistrad Block (Innistrad, Dark Ascension and Avacyn Restored.)
Return to Ravnica Block (Return to Ravnica, Gatecrash and Dragon's Maze.)
Theros Block (Theros, Born of the Gods and Journey into Nyx)
Khans of Tarkir Block (Khans of Tarkir, Fate Reforged and Dragons of Tarkir.
Battle for Zendikar Block (Battle for Zendikar, Oath of the Gatewatch.)

Unless cards have been printed in one of these sets they are not legal for the modern format. Although the format bears the Title of Modern there is plenty of cards printed with the modern card frame that are not legal for this format.
EDIT:
Oh and do remember there is a banned list of cards as well. Do make sure you are not playing any of them.
EDIT:
Do note some of the conspiracy cards are modern legal seeing as they have been printed in a modern legal set before. Reflecting Pool comes to mind.

MTG Conspiracy cards allowed in modern


Two NICs, one with static ip and one DHCP. IP Policy routing

Question: I have trouble configuring a server that I own. It has Linux Ubuntu Server Edition 10.04 LTS as OS, two NICs (eth0 and eth1) and uses OpenVPN.
eth0 is connected to a switch which is connected to a 3G router (static ip: 192.168.0.254) and eth1 is sometimes connected to an (before-hands) unknown LAN and uses DHCP to acquire an IP address. Only one of those interfaces will have an internet access at time i.e. if a cable is plugged in eth1, it is required that the 3G router is shutdown*.
Ultimately, I would like all the traffic to go through the VPN using the interface that is connected to the internet but also all traffic to a specific IP address and port (let's say 192.168.45.1:8443) to use eth1, no matter what.
In the process of setting-up that up, I first concentrated on the 3G part, left eth1 unplugged and managed to use the VPN to communicate with other servers in the VPN over eth0.
/etc/network/interfaces looks like this:
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.0.100
netmask 255.255.255.0
gateway 192.168.0.254

auto eth1
iface eth1 inet dhcp

Then, I plugged an ethernet cable in eth1, disabled the VPN and shutdown the 3G router. The LAN to which eth1 is connected has a DHCP server (192.168.0.254) and happens to have the same ip range as the machines connected to eth0 (192.168.0.x). I can by no means guarantee that both subnets will be different in the future.
The server gets an IP (192.168.0.45) from the DHCP server but neither can I ping it nor see the server in the list of connected devices on the DHCP server interface.
After commenting out the gateway line in /etc/network/interfaces, I'm able to ping the DHCP server aswell as any other server in the LAN but still not the other way around. Also, it only works if I specify the interface to use for pinging:

ping 192.168.0.254
PING 192.168.0.254 (192.168.0.254) 56(84) bytes of data.
From 192.168.0.100 icmp_seq=1 Destination Host Unreachable
From 192.168.0.100 icmp_seq=3 Destination Host Unreachable
From 192.168.0.100 icmp_seq=4 Destination Host Unreachable
^C
--- 192.168.0.254 ping statistics ---
6 packets transmitted, 0 received, +3 errors, 100% packet loss, time 5007ms, pipe 3

ping 192.168.0.254 -I eth1
PING 192.168.0.254 (192.168.0.254) from 192.168.0.100 eth1: 56(84) bytes of data.
64 bytes from 192.168.0.254: icmp_seq=1 ttl=255 time=0.738 ms
64 bytes from 192.168.0.254: icmp_seq=2 ttl=255 time=0.832 ms
64 bytes from 192.168.0.254: icmp_seq=3 ttl=255 time=0.809 ms
64 bytes from 192.168.0.254: icmp_seq=4 ttl=255 time=0.795 ms

--- 192.168.0.254 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2997ms
rtt min/avg/max/mdev = 0.738/0.793/0.832/0.044 ms

I have no idea why it still says from 192.168.0.100 even when pinging on eth1 since it's not its address.
I've read about IP Policy Routing and it seemed to be the way I should head to achieve what I want in the end (among others, forcing traffic to and from a specific ip/port through eth1). If I understand correctly, what could make it impossible to ping the server from any other machine in the LAN is that it returns the whole traffic through eth0 in case it's the default route?
However, when looking at the output of route, it seems to me that the default route is on eth1?
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
192.168.0.0     *               255.255.255.0   U     0      0        0 eth1
default         192.168.0.254   0.0.0.0         UG    100    0        0 eth1

I've read this post and the one linked in it and tried to adapt it in order to make all traffic that goes in eth0 go out eth0 and the same for eth1:
ip route add default dev eth0 table 3G
ip route add default dev eth1 table LAN
ip rule add fwmark 0x1 table 3G
ip rule add fwmark 0x2 table LAN
iptables -A OUTPUT -t mangle -o eth0 -j MARK --set-mark 1
iptables -A OUTPUT -t mangle -o eth1 -j MARK --set-mark 2

But that doesn't work and afterwards, I'm not able to ping the DHCP server anymore. I guess I've misunderstood how that works...
What should I do?
Also, I've left out the VPN part for now but I'm a bit concerned that it will not work as I candidly expected. How do routes and the VPN interact? I need to be sure that the route that forces all the traffic to and from a specific ip/route through eth1, cannot be resolved if eth1 is not connected.
Thank you very much in advance for your help. I would be very happy to provide any other information if needed. Please excuse me if the question was already answered somewhere else, I didn't find it (or if it's too basic).
*it would be even better, if I could configure that all traffic except to and from a subset of IP addresses, would go through eth1 if a cable is plugged in.
Edit>
eth0 is now on the subnet 10.13.37.0/255.255.255.248 and the server has 10.13.37.2 as ip.
All traffic now goes through the VPN but I would like that traffic to 192.168.45.1 (192.168.45.0/24 is the OpenVPN subnet) on port 443, while still using transported throught the VPN, uses only eth1 (thus making it unreachable if no connectivity exists) and traffic to 192.168.45.1 on port 8443 use only eth0. Is that possible?
ip route add default dev eth0 table 3G
ip route add default dev eth1 table LAN
ip rule add fwmark 0x1 table 3G
ip rule add fwmark 0x2 table LAN
iptables -A OUTPUT -t mangle -o eth0 --dst 192.168.45.1 --dport 8443 -j MARK --set-mark 1
iptables -A OUTPUT -t mangle -o eth1 --dst 192.168.45.1 --dport 443 -j MARK --set-mark 2

but using iptraf, I can see that when wget-ing something on either 443 or 8443, only eth1 is used.
Thanks!
Answer: Are you sure to plug the right cable? looks like that you plug the cable of the 192.168.0.x lan to eth1 not to eth0.
if it's not, have you tried to unplug BOTH cable and tries to ping with only one cable plugged? Like:

Unplug both
Plug the 3G cable to eth0 and ping 192.168.0.254
Unplug it again
Plug the lan cable to eth1
run: ifconfig eth1 down
run: ifconfig eth1 up
run: ifconfig eth1 and look the ip

BTW, CHANGE ONE LAN SETTINGS!
If you can't change the eth1 lan configuretion, change the eth0 with 3G router, from 192.168.0.x to 192.168.1.x (to all computer in that lan) or you'll have ALWAYS TROUBLES with same ip lan.
Comment: Thanks! Changing the ip subnet of eth0 has effectively made the server be able to communicate with machines of both eth0 and eth1. But I'm still unable to achieve what I want regarding OpenVPN. See edit above.


Fix iTunes exclamation?

Question: I've moved all of my MP3s to a new location. iTunes appears to still be looking in the old location because it displays no artwork and an exclamation next to each song.
Is there a way to tell it "it's all over here now"?
Answer: What I would do is select all of the stuff in the library and delete them out of iTunes. Then go to where ur music is located and drag them back over.
Comment: Won't I lose info like ratings and play count if I delete them?
Comment: You might. I am not sure.
Answer: iTunes stores the path to the music files in a library file, so moving the files without using iTunes is a bad idea (see this article for detailed explanations).
But there is hope! I transfered my own library from Windows to Mac by editing the iTunesLibrary.xml. The location of all files is stored in that file. There you have to replace the old folder path with the path to your new location. The procedure is detailed here
If you are comfortable with iTunes managing your files you can also move the files back to the old location and then let iTunes perform the move.
See the first link in section "Consolidate: The Right Way".

Fix iTunes exclamation?


I still have the Ubuntu 11.10 screen while booting

Question: I have upgraded to 12.04 but when I boot the PC I still get the purple 11.10 screen with the white dots.
How do I change this?
I am running on an AMD64 processor and have an Nvidia GE 9300 graphics card
Answer: Both 11.10 and 12.04 comes with LightDM.
Purple screen and white dots you are referencing to is actually LightDM welcome screen. It hasn't visually changed between 11.10 and 12.04.
11.10 LightDM welcome screen:

12.04 LightDM welcome screen:


Crystal Lattice Defects

Question: Why do defects in crystal lattices of various molecules and compound occur ?
Is it due to the continuous contact or it arises due to impurities and human error during the formation?
Comment: There are many reasons for the many different kinds of defects.  Vacancies are part of the thermodynamic equilibrium of 'perfect' crystals because of configurational entropy.  The Simmons-Baluffi experiments are the classic example.
Answer: First of all, there are no such thing as a "perfect" crystal.
Defects occur from both human error and the experimental setup.
Defects from human error are primarily due to handling issues, which can never be perfected, especially not if the crystals are solvated.
Experimental defects can occur from either the diffraction experiment or the crystal growth experiment. Impurities can affect crystal growth by displacing the molecule of interest in the lattice and unless you are attempting neutron diffraction, the crystal will be significantly damaged during the data collection.
In my field of protein x-ray crystallography, the typical crystals can have diffraction ranging from nothing at all to ~0.8 Angstrom range (best cases) and as such you can have beautiful crystals that have no diffraction and ugly crystals that diffract very well.
Crystal defects can be perfectly acceptable and are a so common that we usually don't think about them too much.
Answer: A perfect crystal can exist only at 0K. Above this temperature, there is always some energy associated with the crystal which causes some particles to leave the crystal as in Schottky or Frenkel defects, or it allows some impurities to enter.
Comment: Even at 0K (which is impossible to reach) perfect crystals cannot exist, unless you can crystalize a single isotope of each element present... the isotopes will otherwise be randomly distributed... And you better not be thinking of crystalizing anything with radioactive decay products!

Crystal Lattice Defects


Bowing during kedusha

Question: Today at Mincha, the Shaliach tzibbur bowed for each word of Kadosh Kadosh Kadosh, to the left, right, and then center, as we do at the end of Shemoneh Esrei.  I have never seen that before.  Is there a source for this, and has anyone ever seen it before?
Answer: Is there a source? Likely not.
The meaning of Kadosh, Kadosh, Kadosh, following the Targum (as we say in Uva LeZion) is, "HOLY in the Heavens Above, the Abode of His Countenance, HOLY upon the earth, the place where Man serves Him, HOLY forever and ever!" That's up, down, and forever - not right, left & center. (We do tend to bounce upwards with each Kadosh.)
He's likely confusing it with "VeKara zeh el zeh veAmar" - "and this [Angel] calls to this one and says." Since the idea here is that each group of Angels can't say Kedushah without alerting the other groups and saying it in unison, I have seen some bow to the right by the first zeh, to the left by the second zeh, and to the center by veAmar. This is as if to pantomime, "This group on the right, calls out to this group on the left, and they join together in the center to praise G-d."
Comment: I also assumed that he was referring to  "VeKara zeh el zeh veAmar". It is one of many things that people do just because other do, though there is no real Mekor for this. Sefer Minhag Yisroel Torah writes that it is a made up custom with no basis.

Bowing during kedusha


How to setup exchange outlook calendar?

Question: We have a Small Business Server (SBS) Windows 2003, and we need to setup a shared outlook calendar using exchange (comes with the SBS), however my client does not want to use exchange mail. In other words, they would like to use Outlook to send an receive emails using some hosted web mail service (using POP) but have the Outlook calendar shared among users using exchange on local SBS server. All users have domain accounts configured. Is this possible to do?
Comment: From what I know Exchange/Outlook doesn't really work like that.  Unfortunately, it is more of an all-or-nothing type thing.
Comment: Well your clients can just use Outlook and ignore the email functionality if they want but with all due respect this is where the consultant needs to find a diplomatic way of telling the customer that the customer's idea is a very stupid one.
Answer: You mention that the client does not want Exchange email accounts.
Unfortunately modern Outlook does not have a seperate client just for Calendar entries. It used to be known as Schedule+, but was discontinued and incorporated into the office Oulook.
So to setup Calendar access via outlook, your client would still need an exchange site.
Not a problem from the backend using SBS. What you won't need to setup is an SMTP connector for external send/rec.
On the user side Outlook is easy to setup to start with a view of just the calendar folder.
Depending on the version of Outlook this can be done either in the profile or with a switch. You can further restrict Outlook to also not show the other folders, but in reality, althoough Outlook will only be used for internal employee calendar use, they will still need contacts (appointment invitees), deleted items, sent items...
Answer: It's possible but messy, in that you have to create multiple accounts and the Exchange account will include the default folders along with the calendar.

How to setup exchange outlook calendar?


Why does the battery eliminator connected to the wall provide a better spin to my dc motors than my battery of the same voltage?

Question: Using a H-bridge, I've connected my DC Motors to an Arduino. When I accept the external power source from a wall, using a 9V battery eliminator, the motors spin well and consistently. However, when I connect it to a 9V battery, the motors spin slower, and the speed deteriorates till the motors stop. This happens in approximately 5 minutes. I checked with multiple 9V batteries of the same type. I have tested the batteries to check if they're dead after the motors stop. They are not, and if I reconnect the motors to them, the same process occurs all over again. I have checked for short circuits, and there are none. Any possible ideas as to why this is happening?
Comment: Does the battery heat up? If you immediately disconnect then reconnect after running down do the motors go again?
Comment: No, the 9V battery does not heat up. Once i reconnect, the motors spin, but still very slow compared to the wall power.
Answer: First off, never use 9V batteries to power motors or any device that consumes more than a few hundreds mA. Those batteries are just too weak.
Now a battery eliminator is not a pure equivalent as it can typically supply 800 mA or more, depending on the model you get.
The only commonalities between the battery and the eliminator are the 9V voltage and the socket.
If you want to power DC motors with batteries then rather use several 1.5V batteries in series.
Comment: Yes - those 9v batteries are series strings of *tiny* (smaller than AAA) 1.5v cells, simply use the same idea with larger AA, C, or D cells.
Answer: The question is not about volts, but current.
A 9V battery is notoriously bad at powering anything that requires high current, like running a motor. Due to to chemical nature of the battery, the 9V will struggle to keep supplying enough current and will fairly quickly drain.
A regular alkaline 9V block can supply you with 565 mAh, which is not much if you power motors. You'll have more luck with LiPo (lithium polymer) batteries, which are capable of supplying 2200 mAh or more!
To learn more about different types of batteries check out https://learn.sparkfun.com/tutorials/battery-technologies
Wall power can quite easily provide the required current your motors need.
Answer: Batteries use a chemical process to produce power. If you draw to much current (motors use quite lot) the chemical process can't keep up and the voltage will drop, resulting in a slower running motor. Try connecting two batteries in parallel. That way each battery only has to produce half the current.
Comment: That's not really a good solution.  What's missing from the analysis is that the process you describe - in effect the internal impedance - is very limiting for the 9v "transistor" battery, and it simply should not be used for most motor loads.


How to choose a key signature for a song that modulates often?

Question: In jazz, let's say, how would one choose a key signature for writing a lead sheet for a song where keys change every few measures or faster? Is writing the key changes explicitly going to be helpful or distracting? And if it isn't helpful, should you just choose C, and just label accidentals as they come up? What's best for a player to read?
Comment: Are you sure the key is changing? If you change keys every few measures, it sounds to me like they might simply be chord changes, not modulations. But I also know that jazz can involve some unusual music theory...
Comment: Yes, it uses tonicizations as well as actual modulations.
Answer: This depends on the circumstances, but I would suggest it is more common to write no key signature (or the best closest match like "F" if all B tends to be Bb.) especially in the case of changes that last only a few measures. Here are my reasons:
1) It's not normal for jazz music to include alot of key changes written as new key signatures. This will happen if a whole section (consisting of 8 measures or more, for instance) is in a different key, but I think it's the exception rather than the rule.
2) Writing a key signature is more than just a matter of ease and convenience for displaying notes in the simplest fashion. At its core, writing a key signature communicates that the tonality of the piece has changed and in jazz music there is a high tolerance for temporary adjustments of tonality that are not interpreted as key changes.
3) Many sight-readers will be more confused by lots of key changes than by lots of accidentals.
If you look through the Real Book, or transcriptions of jazz solos that may also help you get a sense of what the conventions are. In general, though, there are no hard rules and there may be multiple solutions that are technically correct. I think it's best to defer to the norm and also to what your players expect. If you write the music in a way that they find unnecessarily difficult, be prepared to hear a few complaints from them. :)
Answer: I'd say to write all the key changes.  Average sight-readers should be able to glance at it and instantly recognize it and reposition.  If you're writing accidentals then they have to check every single one.  That isn't a problem for experienced sight readers, but it's still more work.
Answer: In this case, as someone who sight reads jazz, I would definitely agree to start with the first key and write key changes within the song, unless it's very often. there are certainly some songs that are written all in accidentals a because there simply is no key for the song.
if the key changes are helping the ready by providing a clear view of what's happening, write the key signitures. if the changes are hurting the reader because the chart is cluttered with a key change every few bars, leave it out. Use your best judgement to have the cleanest, most obvious, and most clear chart as possible.
Answer: It depends how much and how often the 'key centre' is going to move. Any piece will have what most would call a 'key centre' as in the start or finish sounds like home. This then would establish the key for the piece. A key signature would then be helpful. For changes of a bar or two, usually accidentals are used - they tell the reader that something has moved, but will come back to key at some point. If the modulation is for,say, 4 or more bars, then a key change is probably in order, so the reader can 'change hats' for a comfortable time.I'd also say that note changes for a bar or two would be better accepted if they followed the original key, as in start with flats, try to use flats. But there are some readers  who prefer the 'correct' notation with sharps in this case, because they see better where the music is going.


Sql Server improving performance with monitoring etc

Question: What are some ways I can constantly monitor and report on my production sql server so that I can determine where locks and performance improvements can be made?
Answer: This is a very open ended question and the answer varies whom you talk to as there is so much that can be done.
At a minimum, you should do the following.

Look at these diagnostic queries from Glenn Berry and find out the expensive procs based on IO, CPU etc...

http://sqlserverperformance.wordpress.com/2011/05/16/may-2011-sql-server-2008-diagnostic-information-queries/

Look at Perfmon counters and act upon what you find that stand out.

http://www.brentozar.com/archive/2006/12/dba-101-using-perfmon-for-sql-performance-tuning/

Look at memory usage, plan cache etc...
Look at sys.dm_io_virtual_file_stats and identify if you have IO bottlenecks
Proper Index maintenance including updating the statistics
Use sp_whoisactive to look at the current activity on the server.

http://sqlblog.com/files/folders/release/entry35240.aspx
This is a very high level starting point and don't consider this as a final list though.
Answer: Being able to monitor the SQL server continuously can provide valuable information about performance and effectiveness. Fortunately, these capabilities are fairly straightforward to use for those with administrative capabilities on the server.
When the server was first installed, certain performance measurements were automatically installed along with it. The performance tools allow for real-time monitoring, local monitoring, and remote monitoring. Additionally, they can be used to create logs and charts based upon the performance which can lend themselves to analysis and reports of the SQL server.
Real Time, Continuous Monitoring
The administrators can access and modify these monitors by going to Start, Programs, Administrative Tools, and Performance. The administrator will want to add counters to monitor the server according to their desired performance criteria. They can elect to add all the counters available, or hand select particular monitoring tools. Some of the more popular and relevant tools include the capacity to monitor the memory usage of the server, the CPU activity, paging, the amount of time a select disk is busy, and the amount of time the processor is performing operating system processes.
Logging and Reporting Information
Once the real-time counters have been established, administrators should then proceed to the Performance Logs and Alerts window. From there, they can right click on the Counter Logs and select New Log Settings. They should then add the counters they want to have recorded. There is also an option to add a specific period of data to record. If this is not utilized, then the system will continue to record the information until it is personally stopped.
After the period of logging the data is completed, the information is easily converted to charts and graphs. Begin by opening the System Monitor, click on the View Log File Data button, followed by a click on the Add button. If the information was logged for an extended period of time and all the data is not required for the analysis, the Time Range sliding button can be used to select a specific period of time. Under the Data tab, the administrator selects the counters to be included, followed by the Graph and Appearance tabs to select their preferences in that area. The information will then be converted to an easy to view chart. The information can also be exported to Excel for additionally monitoring and reporting.


Bias Tone in Old Film Audio

Question: I'm conforming and repairing a foreign language version of a classic 1941 film.  Among it's many problems is an inaudible high frequency tone that screeches when I scrub. Obviously slowing makes it audible.  I'm working in Pro Tools.  The source is, of course, mag.  You can see the high frequency saw tooth tone when you zoom in.  Some mistake must have been made somewhere in the recording or transfer process. Is this bias and how did it get there? What causes this and should I try to remove it?  I have iZotope I can afflict on it if the consensus thinks it should be removed.  Thanks for the help!
Answer: Well if it is inaudible, unless you plan on pitch shifting the audio down, it sounds like it doesnt need to be removed?
It is probably there because when it was transferred to mag, it may have transcoded frequencies from the mag above the our audible range and when you scrub, your pitching it down in varispeed which would cause it to fold down higher frequencies into the audible spectrum.
But if you do want to remove it, why not just use iZotope spectral repair and do a vertical attenuation on a 4096 window?
Not sure if that helps at all..
Answer: Try doing a varispeed on a section of the file, slowing it down by 50%.  Then run that through spectral analysis to find the pitch of the tone (or sweep it with an EQ).  Then, simply notch out the actual tone (existing at 2x that frequency) from the original 100% speed.  If everything's within the 48k domain you should be fine since your within the Nyquist limits that all major EQs tend to cover.  If you're in the 96k domain and beyond, you may have to rely on something like iZotope to filter it out since EQ plugin's don't go beyond the frequencies excited within the 44.1/48k range, at least any of the ones I've worked with.  Or, cut the speed in half, do the notch, and 'un-do' the varispeed.  I'd consider that more of a last resort though since the double varispeed may have affects on the integrity of the source.

Bias Tone in Old Film Audio


remove 12.04 which installed by wubi and install 14.04

Question: I have windows seven also I installed Ubuntu 12.04 with Wubi. I haven't had any problem with my 12.04. Now I downloaded 14.04 32 bit and I make my flash boot able with this guide also I uninstall my 12.04 from add or remove program !! (...Wubi make this ability ) Now what next? When I start my computer still I see grub (But I think I should not see that because I uninstall that from win 7 ) also what I should do with my boot able flash- which I installed 14.04 on that- in order to install that. Note My aim is to format windows 7 and 12.04 and just have 14.04 on my computer.
Answer: Solution:
1) Back up your data
2) Place Ubuntu 14.04 on flash drive, hard disk, cd, etc using unetbootin or YUMI
   (preferrably YUMI)
3) Select your device from boot menu
4) Run and select "Install Ubuntu"
5) Select "Erase disk and install Ubuntu"
Comment: just I want to add this by F2 in ASUS laptob we can go to boot menu
Answer: or you can also upgrade it to 14.04
first upgrade to 13.04 than 13.10
after tat you would be able to upgrade it 14.04
Comment: WUBI and upgrade is a bad idea.
Comment: He wants to remove Windows. This wouldn't work.


Is there a generic rulebook for Powered by the Apocalypse?

Question: Does a generic rulebook exist for the system behind Apocalypse World (Powered by the Apocalypse)?
Answer: There is no generic edition of Apocalypse World — that is, an edition with the setting stripped out and "just" the rules.
This is for the simple reason that the rules effectively are the setting, so there's no way to have "just" the rules. All the other Powered by the Apocalypse games were created by playing and studying Apocalypse World (and other PbtA games) to understand the design patterns involved, and then adjusting the rules to create rules that embodied a new setting.
However, one of the most well-respected designers of PbtA games — Avery Alder of Monsterhearts fame — has created a free PDF meta-game called Simple World (alternative link due to today's server issues) that is kind of like a playbook for a PbtA game. You follow the instructions in Simple World, and the result is a GM's Agenda, Principles, and Moves that are customised for the setting and themes you want to play with. It meanwhile instructs the players in how to create characters that suit this custom set of rules. This is as close to a generic set of PbtA rules that exist. Creating a game is fast (you do it together as a group while the players make their characters), so you can create a custom PbtA game and start playing in one session.
And once you've created a PbtA game with Simple World, you can always continue to adjust, tweak, and refine it, along with formalising some iconic character playbooks, ending up with a true stand-alone PbtA game of your very own design.
Answer: The closest I've seen to generic rules from a full game of Powered by the Apocalypse is The Bureau, which is a free game.
Comment: Welcome to the site! Please take the [tour] when you get a chance. Can you go into more detail about The Bureau and why it would be a good starting point for a generic Powered by the Apocalypse game?
Comment: Was [this](http://story-games.com/forums/discussion/17652/apocalypse-world-for-kids-the-bureau-an-aw-hack-with-different-die-types) The Bureau being referred to?


Doing BIAB with several smaller bags instead of a big one

Question: So I was thinking about switching from extract with grains brewing to all grain brewing using the BIAB method.
I had this idea to use several of the small disposable bags I get for the grains in the extract and grains method instead of a big one for all of the grains. Is there a down side I'm not seeing for this method?
Answer: A brewster friend had just such a set up for all-grain brewing. It seemed to work well and the beer was fine. It seemed easier to handle the smaller bags as they were not as heavy (or so full of wort).
Comment: No - the beer seemed fine. Just like a real AG brew.
Comment: Did it affect the quality of the beer he made for the worst?
Answer: In theory this would work.
The only caution would be to make sure your milled grain very well blended to have even portions of each grain in each bag. Since mixing it as a whole as  once in the mash would not be an option as easily if it was one a large bag.
Reason for this is to to make sure enzymes from your base malt are everywhere so your mash gets even coverage for conversion.
For example. Say you use 3 bags. 2 have your base malt and the third is filled with specialty grains with no or low diastatic power. The third bags area would result in an unconverted starchy mess.
Comment: since the enzymes dissolve into the water I don't think even distribution in the bags is too big a deal
Comment: @DennyConn true, but I could see a bag of just oats becoming just a dough ball with a starch slime barrier.
Comment: Let's say I blend them together and then distribute them between the bags, problem solved?
Comment: @WildLAppers yes
Comment: @EvilZymurgist, yes, but you were talking about enzymes, not physical attributes, so that's what I was addressing
Answer: I have been using this method for three years or more, starting off with four bags and then cutting back to three, with between 1.5kg and 2kg per bag. If mixing grain, I split the different varieties equally between the bags. These are what we call laundry bags in Australia (designed to hold delicate items in washing machines).
Initially I used to tie the bags with twine, then moved to zip ties, before eventually sourcing some bags with built in zip closures which are excellent.
Care needs to be taken when adding bags to strike water in order to avoid any dough balls. My method is to add one bag at a time, using a paint stirrer to turn each bag over thoroughly to ensure that all grain comes into contact with the water.
There has been no need for me to reveal my method to fellow AG brewers, and they have given many of my beers the "thumbs up", with none of them querying my procedures. Most of these beers are in the 5%-6% ABV range.
It beats the hell out of lifting one bag, especially when I have nowhere, and I mean nowhere, to install a pulley lifting system. As a matter of fact, I would not be doing BIAB if it were not for the multiple smaller bag method.
Comment: Superb - love the answer. I read a piece on beer history recently that claimed BIAB multi bag is probably  the oldest form of brewing, and that the mash tun / sparge system is a relatively new invention so that much larger volumes can be made. So, it's like a new old method.


Why do people buy US dollars on the black market?

Question: I was reading news articles about people in Venezuela and Iran getting a poor exchange rate for US dollars on the black market.  Why do these people need to buy dollars?  Why is it still worth while to buy dollars at an unfavorable black market rate?  Why would Venezuela want to block the sale of dollars?
Answer: A falling exchange rate is an indication of falling confidence in a currency.  Countries like Iran or Venezuela, with a managed exchange rate, set their exchange rates at a higher value than the market accepts.
Such market expectations may be influenced by poor government management, interventions into markets (such as nationalising businesses) or general instability / scarcity. The governments act to manage that uncertainty by limiting the availability of foreign exchange and pegging the exchange rate.
Since there is an inadequate supply of trusted foreign currency people turn to informal exchanges in order to hedge their currency risk.  This creates a positive feedback loop.  People in government who have access to foreign exchange start to trade on informal markets, pocketing the difference in the official and unofficial rates.  The increasing gap between the two rates drives increasing informal market exchange and can result in speculative bubbles.
Driving instability (or economic contradiction) is that the massive and increasing difference between the official and market exchange rates becomes a powerful form of rent for government officials. This drives further state-led rent-seeking behaviour and causes the economy to become even more unstable.
If you're interested in a more formal academic study of how such parallel markets in currency arise, "Zimbabwe's Black Market for Foreign Exchange" by Albert Makochekanwa at the University of Pretoria is a useful source.
Comment: Today's edit (negative feedback -> positive feedback) highlights an issue with this answer. If people are selling US dollars on the informal market, that would tend to *reduce* the discrepancy between the official and unofficial exchange rates. This is similar to other forms of arbitrage, which cause markets to converge, not diverge. Thus, negative feedback is an accurate description, but the answer is not clear about this.
Comment: The link appears to be broken. This one should be more persistent: http://hdl.handle.net/2263/4396
Answer: As a Venezuelan who used to buy USD, I believe there is no better explanation than the one given by someone who actually lives and works here in Venezuela.
Back in 1998, when Hugo Chavez took the presidency, we had a good economy. Fast forward 10 years and you could see how poor management, corruption and  communist measures had wreaked havoc in our economy. It was because most of the money (USD) coming to Venezuela was not invested here but, instead, given away to "pimp countries" like Cuba. Remember, communism lasts while you have money. Back then, we had an oil barrel going over 100 USD and crazy amounts of money were coming into the country. However, little to no money was invested in the country itself. That is why some of the richest people with bank accounts in Switzerland are Venezuelans who stole huge amounts of oil money.  I know this is a lot to take in, but all of this led to the Venezuelan economy being the worst in the American Continent and because there isn't enough money inside the country to satisfy the inner market, people would pay overprice to have anything that is bought abroad. You have to consider that only a very small amount of people can actually buy USD here in Venezuela. Back in 2013, I was doing it. I could buy about 80 USD per month with my monthly income. However, nowadays that's nearly impossible for about 99% of Venezuelans.
To Illustrate.
Minimum wage = 10.000 bolívares / month
Black market exchange rate (as of January 2016) = 900 Bs per 1 USD
10.000/900 = 11,11 USD.   <<< that is what about 50% of Venezuelans earn every month.
That's why this happens. The guy is holding a huge stack of money of the highest Venezuelan note, which he got from exchanging only 100 USD.
I am a computer science engineer, the monthly income for someone like me is about 30.000 bolívares — so that is about 34 USD a month.
oh dear!
So finally, answering your question
Q: Why do people buy USD even at this unfavorable rate?
A: There are many reasons but being the main 2 the following

Inflation in Venezuela is crazy high. The inflation from 2014-2015 was 241%. Which means that having The Venezuelan currency (bolívares) in your bank account makes no sense. In two weeks you won't be able to buy half of the things you used to with the same amount of money.

A huge amount of Venezuelans dream with living abroad (myself included). Why, you ask? Well, sir, it is certain that life in this country is not the best:

You can't easily find basic products like food and toilet paper

Crime rates are way too high (90 violent deaths per 100.000 inhabitants)

It is nearly impossible to buy a car or an apartment with current inflation rate.

the list goes on and on.

I hope you can understand better why people in 3rd world countries and crappy economies buy USD even at an unfavorable rate.
The last question was:
Q: Why would Venezuela want to block the sale of dollars?
A: Centralized currency management is an economic measure that should last 6 months tops. (This was Argentina's case in 2013) but at this point, reverting that would take quite a few years.  However, Turukawa's wikipedia link explains that very well.
Regards.
Answer: The main reason people buy dollars (or other currency) on the black market is because they are prevented from exchanging currency on the official government market. Venezuela for example restricts citizens to a maximum number of dollars the citizen can buy or sell per year, depending on various factors such as whether or not the person is studying at a foreign university.
If the citizen wants to exchange more dollars than legally allowed, that person must buy or sell at the "black" market rate, rather than through the official/government market.
Answer: To understand why people of other nations buy US dollars on the black market, we have to take a step back and understand that the US dollar is the worlds reserve currency and has been so for over a quarter of a century I believe.
Now, to understand the US dollar as a reserve currency, we must understand Triffin's Paradox. The basic idea is that when one nation's fiat currency is used as the world's reserve currency, the needs of the global trading community are different from the needs of domestic policy makers.
Prior to 1971, the dollar was backed by gold, which acted as a supra-national anchor to the dollar's reserve status. The gold standard inhibited both massive trade deficits and money creation, so it was jettisoned.
The Triffin paradox is a theory that when a national currency also serves as an international reserve currency, there could be conflicts of interest between short-term domestic and long-term international economic objectives. This dilemma was first identified by Belgian-American economist Robert Triffin in the 1960s, who pointed out that the country whose currency foreign nations wish to hold (the global reserve currency) must be willing to supply the world with an extra supply of its currency to fulfill world demand for this 'reserve' currency (foreign exchange reserves) and thus cause a trade deficit.
So, what does that mean?
It means that the US dollar is considered the most stable currency on the planet and as such, acts as a reserve against all the other currencies and thus nations like Venezuela, Iran, etcetera, must hold US dollars as a safety net against their domestic fiat currency.
There is also the issue of their governments being required to pay their debts in US dollars.
So, why do these people need to buy US dollars on the black market? Well, they used to buy their US dollars at a currency exchange store in order to preserve the value of their savings. Similar perhaps to how Americans may buy gold, stocks or bonds.
However, their local government passed a law to control the exchange rate, or how many dollars they can buy or just plain and simple made it completely illegal to buy these dollars.
So, like with all laws that make a product illegal, people don't just go away and say okay I will never touch it again, they just go and get it on the black market.
Why is it still favorable to buy US dollars at an exorbitant black market rate?
The black market rate is actually quite reasonable when you consider that by making the US dollar illegal to hold, you have just increased its value by turning it into something scarce or difficult to obtain and people continue to pay black market rates because no amount of law will stop a human being from doing his best to preserve the wealth he worked hard to obtain, especially when you need that money to pay for baby food.
So, your baby goes hungry because nobody wants your worthless bolivares or because you need to bring a truck load just to buy a couple of jars of beech-nut and some formula, or have an easier time obtaining these with dollars because once the person who has all the baby formula hears you got dollars, they are throwing themselves at you to sell you the baby food you desperately need.
You used the term unfavorable, so now based on what I wrote. What is more unfavorable, paying through the nose or your child going hungry?
Why would Venezuela want to block the sale of dollars? Why would China? Why would India? Why would Iran?
Because it leads to financial insecurity and instability of its local economy. As people trade in their local currencies for US dollars, they now have a currency that they can even export abroad as they look to high-tail it out of the economic death spiral their nation is in. Their dollars can be waiting for them at the other end of that plane ticket, while their nations local economy continues to sink like the Titanic, in other words, capital flight is one biggie.
Capital flight is people and enterprises moving their capital (cash and liquid assets) to an overseas "safe haven" to avoid devaluation of the currency or confiscation of their capital/assets. (Devaluation can be seen as one method of confiscation; high taxes are another.)
Capital controls, also known as the question: why would Venezuela want to block the sale of dollars? is the Central State's way of stemming the flood of cash leaving the country. Why do they want to stop money leaving? If we think of each Central State as a neo-feudal fiefdom, we understand the motivation: citizens are in effect serfs who serve the State and its financial nobility. If the serfs move their capital out of the fiefdom, it is no longer available as collateral for the banks and a source of revenue for the State.


How to combine various armatures?

Question: I put together an armature for a four legged creature, but I had to make each leg armature separate. I now want to combine them into one armature. Is there an easy way to do this?
Comment: Do you want to keep the four legs for deformation of the mesh and have another one to control the movement?  I guess you don't want to let the legs move synchronously (This wouldn't look like walking). Could you explain a bit more how it should move.
Answer:
Select all the leg armatures, in Object mode.
Go to the Object menu, >> Join (or Ctrl + J).

That said, I hope you didn't weight paint anything yet, because if so, you may have to rename some of your bones' VGs.
Comment: This technique combines the formerly separate armature objects into a single armature object consisting of four discrete sets of bones. If your intent is to combine them into a single set of connected bones, you'll have to make the connections manually after you follow the procedure  Mike described.
Comment: Thanks @Mike Belanger. As usual the solution is super simple, hehe. You really saved my life :). Upvoteded.
Comment: How do you make the connections manually? I don't see an option in the "Bone" context -> "Relations" -> "Parent" to set the parent to a bone of another armature.
Answer: You can combine the bones into a single armature using the method Mike outlined. But while the four leg armatures are all part of the same armature, they are not physically connected. To connect them together into a single entity, you will have to construct the desired connecting bones yourself.

How to combine various armatures?