Self-Study Plan for Becoming Statistical Analyst?

Question: Can any one please suggest me a self-study plan for becoming a Statistical Analyst? I need suggestion something similar to Self Study Plan for Quantitative Analyst
Comment: What is your definition of "statistical analyst"? Have you looked through the various other related questions on this website that discuss this? If you can edit your question to more clearly distinguish it from those, that would be helpful.
Comment: I would be helpful to state your current level of knowledge and background, particularly what level of maths you have.  Also if you are working for a company, what stats software do they use, though as per the answer below, R is always an asset.
Comment: I've masters degree in Computer Application and my maths understanding is 6 out of 10. The thing is I wanted to switch my job and really interested in Statistics but don't know where to start and what to read. I've studied maths and stats in last 6 months here and there but what I need is a defined path.
Answer: I am currently in the process of doing this (sort of), and think I have had moderate to great success. I have relied solely on primary literature and experience without any textbooks. Here is what I found most helpful:
1) Learn R. I don't see how anyone can get an intuitive understanding without running many, many simulations. Perhaps with a strong math background this is not as necessary.
2) Learn the history of statistics and the source of various controversies, for example bayesian vs frequentist (Neyman Pearson, Error Statistics) vs fisher (inductivist) vs likelihoodist vs the NHST (Null Hypothesis Significance Testing) hybrid. There may even be more! Especially learn about the history of the NHST hybrid controversy, I had no idea how bad it was and was taught that as "Statistics".
3) Get data of the type you think you will analyze (timeseries, comparing groups, etc) and analyze it in many different ways to learn the strength and weaknesses of different approaches.
Answer: I'll answer from the perspective of an economist who did lots of econometrics.
If you haven't done any R/Python/Matlab etc. and you want to be able to use statistical techniques, understand when to use which, how to apply them I'd suggest you start with Chris Brooks' Introductory Econometrics for Finance. The book uses EViews for all examples, and it's great for a beginner as it explains both the theory, gives an example, and then shows you how to do it step by step. I loved it!
If you want something more interactive, and with programming head over to coursera.org and check out their Stats 101. I think it uses R, and will have plenty of reference material.
Answer: I am a college dropout and have done this successfully. So follow the steps i enlist below :

Learn R or Python.
Try to understand what a probability distribution is.
Learn about the Normal, the binomial and the uniform distribution. Consider only a single variable.
Find out as many situation where the above three distributions have been applied and find out as many properties about these as you can.
Try and visualize two variables, both normally distributed. in one case they are positively correlated and the other case they are negatively correlated.
Try to plot different variables and try to find differences between them using just what you see in the plots.
Once you have done this, take up any dataset(s) and start finding things about it using the distributions and the plotting.
generalize your knowledge to other procedures like regression.
generalize your knowledge to other distributions.

Some books to help you out :

http://www.amazon.com/Statistics-An-Introduction-using-R/dp/0470022981
http://www.amazon.com/Using-Introductory-Statistics-Chapman-Series/dp/1584884509/ref=pd_sim_b_5
http://health.adelaide.edu.au/psychology/ccs/teaching/lsr/

Finally start analyzing something that you like using the techniques that you have learned. Now you are ready to go to the advanced level.
Answer: Learn R. Absolutely, definitely do so. R is open source and I think will soon become the de facto standard for the statistics & machine learning. You also need to learn a scripting language and I would strongly recommend Perl. It doesn't have the fanciness of other languages but it is super powerful and guaranteed to be a solid return on invested time, not to mention the vast swath of packages that are already created for you on CPAN. Finally, you also need to get your hands on some books to learn statistics. Some of the best books in statistics, can be found here. Linear algebra is also a good to know but not necessary. If interested here is a list of books for learning linear algebra. HTH
Comment: Can you clarify why you recommend a "scripting language"?


How to have Dapper iterate a stored procedure for inserts?

Question: I have the following Dapper command to insert values into a table using a stored procedure.
sqlConnection.Execute(
       "sp_LocationTypes_Insert"
       , parameters
       , commandType: CommandType.StoredProcedure
       );

where the parameters are created using
var parameters = new DynamicParameters();
parameters.Add("@updated", dbType: DbType.DateTime, direction: ParameterDirection.Output);
parameters.Add("@description", locationType.description);

In addition, the SP needs to be executed multiple times, once for each LocationType object in a list. I could put the list in a loop and call the Execute command for each instance. However, is there a way to have Dapper iterate the list of objects and execute the SP? I do not want to put the T-SQL as a string.
Answer: I have spent a while in the Dapper Source and have seen nothing in regards to dapper iterating internally like you are asking.  For this question i referenced Dapper's unit tests and i can find no example of dapper attempting to do this.  With this being said, i would assume it does not.
Here is the link to their general unit tests, if you browse up a level they have it organized into other sections.
https://github.com/StackExchange/Dapper/blob/master/Dapper.Tests/Tests.cs
I consider this to be my comprehensive guide on 'how to use' dapper.


Seggregating the output of a query

Question: My question might seem weird. But I need to know whether we can identify and seggregate the rows fetched from particular table in a query, which is formed by joining tables.
Please refer the below query if I am you are not clear with my question.
My requirement is to know the rows fetched from table 'rel' alone in the query.
<code>SELECT rel.*
FROM rel,  C
WHERE rel.col1  = C.col1
AND C.col1 NOT IN (SELECT R.col1 FROM R WHERE R.col2 = 'MN')
AND rel.col2= 'MN'
AND rel.col3= 'MN'
AND c.col2  ='MN';
</code>
Thanks,
Savitha
Comment: Your question does not make sense, yet. What do you mean by a "row fetched from a particular table in a query"?
Answer: Since you are performing an INNER JOIN by using the comparison in the WHERE clause, all your records, by definition, are coming from the rel table.

Seggregating the output of a query


How to call a silverlight application from another silverlight application

Question: How do I call a silverlight application from another silverlight application. I want to do it when User RMB click on the menu item on the treeview from first application.
Please note these menu items are added dynamically hence I can not add the code in the XAML file.
Please help in this regard.
Answer: Are you asking how two separate running Silverlight applications can communicate with each other?  If so you can use the Messaging API.  You simply need to set up a receiver and sender.  http://mark.mymonster.nl/2009/10/07/silverlight-3-local-messaging-explained-enhancement


Did the ancient Romans know and use the catenary test when building arches and bridges?

Question: I am trying to understand if ancient Romans understood and used the catenary test when building bridges. I cannot find anything online
Comment: Could they build catenary structures? Clearly yes. What, precisely, do you mean by 'catenary test' here?
Comment: The Romans filled their spandrels, so a catenary would not be an optimal load-bearing shape! Even if the word is latin, it is a neologism often attributed to Thomas Jefferson.
Comment: I mean that an arch passed the catenary test (and hence an arch can hold its own weight) if a chain can hang entirely inside the profile of that arch
Comment: I concur with the comment by Cosmas Zachos. The catenary shape is valid only for the case where the weight per unit of length (length parallel to the curve) is *uniform*. When the spandrels are filled the sides of the arch are subject to a larger load than the center. For an arch with a span to height ratio of 2:1, with filled spandrels: in that case a semi-circular profile is certainly superior, and quite close to optimal. Example of roman ingenuity: in the construction of the Pantheon dome: for the upper dome levels pumice was used as aggregate in the concrete; they were working the density
Answer: Not in any explicit way. The observation that compression forces in an arch invert tension forces in a cable, which led to the "catenary test" for arch shapes, was only made by Hooke c. 1670. According to Earliest Known Uses, the name linea catenaria for the hanging chain curve first appears in Huygens's 1690 letter to Leibniz, who then popularized it in a 1691 Acta Eruditorum paper.
Nonetheless, Huerta in Oval Domes suggests that there was rudimentary practical understanding, gained by trial and error, of what the "catenary test" will later spell out :

"In the first two millennia the builders experimented with several types of arches and
vaults and there is no direct line of progress towards the voussoir arch with radial joints,
which is our conceptual model... The first vaults were quite small, with spans of only about one or two meters, just enough to cover the tomb. This size favoured experimentation: the vault, if not of an adequate form, will distort and the observation of the movements gave the builders a
"feeling" for the more adequate forms...

To an architect or engineer with some experience in masonry structures it will be evident that the vault at the bottom right side is the safest, adopting an oval form which will amply contain the trajectory of compressions (the line of thrust or inverted catenary) within the arch.
Choisy [1904] was the first to point this fact as the origin of the oval arches. [...] If all the voussoirs of the arch are the same size the line of thrust will have very nearly the form of an inverted catenary. But, it is not necessary that the arch have the form of catenary: it suffices that the catenary can be contained within the masonry."

So even to the extent that line of thrust considerations were understood they were not necessarily reflected by the shape of arches directly. In particular, Romans disfavored oval shapes close to the catenary, preferring circular arches and domes for aesthetic reasons:

"It appears that the Romans did not built oval domes: the central symmetry was considered a requisite and even in the experimentation of the domes in Hadrian's Villa all the forms present a centralized character. Some exceptions may be found in the apses of thermae, and it is usually presumed that the octagon of the church of St. Gereon in Cologne rests on the oval foundations of a previous Roman building. Choisy discovered that in the bridge of Narni, the central span of the inclined road was adapted by using an arch formed
from two quarter-circles of different radii. Perhaps more examples can be found, but it
appears that the Romans used the oval form for arches and domes only in exceptional cases."
Comment: Thank you very much @Conifold


What exactly is a key in cryptography?

Question: After researching and reading I am not sure if I completely understand it. To my knowledge, a key is a password used to decrypt a message. However, the confusion comes in when it comes to the public key, is the recipient putting in the password to receive the message?
Comment: [This answer](http://security.stackexchange.com/questions/65622/client-server-encryption-technique-explanation-tls-ecdhe-rsa-with-aes-128-gcm-s/65645#65645) explains the different portions of cryptography, and might be helpful to you.
Comment: [This video by Computerphile](https://www.youtube.com/watch?v=GSIDS_lvRv4) or [this one by Numberphile](https://www.youtube.com/watch?v=M7kEpw1tn50) are good introductions.
Comment: The [Wikipedia](https://en.wikipedia.org/wiki/Key_(cryptography)#Key_vs_Password) has a section explaining the difference between keys and passwords.
Answer: Passwords are concerned with system access. They are used to verify that you are who you say you are (example: logging into email), or at least that you are someone that is allowed to access the resource you are trying to access (example: a code to open a door).
The important thing about passwords is that they are fed into a system, so extra measures like lockout (too many wrong attempts) or 2-factor verification (texting a code to your phone) can be implemented.
Keys, in the context of cryptography, are not passwords, they are used to change a message (plaintext) into an unreadable form (ciphertext). Think about it like this: you have an encryption machine. You feed your plaintext and your key into the machine and get scrambled letters and numbers out (the ciphertext). You secretly share your key with your friend, then you can send him your ciphertext, and it doesn't matter who sees it. Since your friend had the key, he gets your ciphertext and feeds it into his decryption machine along with his copy of your key, and the machine prints the original ciphertext.
This is a little more difficult to secure: there is a principal in cryptography that says you must assume that an enemy has intercepted the ciphertext and has a copy of the encryption and decryption machines. So he can try as many times as he's like to guess the key and there's nothing you can do to stop him.
The above describes a symmetric cryptosystem, where you kept the encryption key secret because the same key is used to both encrypt and decrypt the message (like locking a deadbolt on a door). This is different form asymmetric cryptosystems, in which the encryption key (the key used to lock the door) is different from the decryption key (the key used to unlock the door). This has the advantage that 2 parties don't need to secretly share the key before communicating. For example, I post to an online forum
"Bill, what's your address? - Please encrypt the answer using the encryption key 103234".
Now, Bill can encode his answer and post it for all to see, but because only the encryption key has been shared and I kept the private key to myself, so only I can decrypt it (not even Bill can decrypt it, even though he already knows the plaintext). Furthermore, now anyone can send me messages that only I can decrypt.
Note on terminology: an encryption-only key is usually called a "public key" since everyone can see it; a decryption-only  key is usually called a "private key" since you don't share it with anyone.
Technical note: while asymmetric cryptography seems superior, it is a LOT more computationally intensive (bad for, say, encrypting terabytes of info) compared to symmetric cryptography
Answer: I am not sure I can answer this question perfectly, but I'll try.
First off, think of symmetric algorithms.
One such algorithm is a method to encipher(encrypt) a message, and must be completed with a key, in order to tell the algorithm exactly how to encipher said message.
The enciphered message is called cipher-text.
The recipient of the cipher-text must also feed the same key to the decryption algorithm in order to recover the original message from the cipher-text. If you don't have that key, you can't read the content.
Public key cryptography can be a bit confusing, and even classic cryptography experts used to think it was impossible to do.
Public key (asymmetric) algorithms are similar to private key(symmetric) algorithms in that they both require a key for encryption and decryption, however with the first one, sender and recipient use the same key, and must keep it a secret, but with the second, two different keys are used for these two operations, one public, which the recipient wants everybody to have, that is used for encryption, and a second, private, that is used for decryption
and must be kept secret by the recipient.
To go back to your literal key analogy, you may think of symmetric algorithms as vaults, that can only be accessed by people who own a key, and of asymmetric algorithms as mail boxes where anybody can insert anything, through the slot(public key), but can only  be opened by the box owner who has the mail box key(private key).
Comment: I had a task today that involved a PKI and was able to understand it better. I had the user encrypt his outgoing messages in Outlook 2013. Only the recipient who has the private key that matches the public key used to encrypt the message can decipher the message for reading; also for additional security I suggested the user, uses a digital signature to sign the message. The main thing that's confusing to me is how is it formed if it's separate from a password. More like the science behind it, but that will come a long to me with more experience and studying, thanks.
Answer: Early forms of cryptography were based on secret encryption algorithms, but it soon became apparent that this was a terribly bad idea. If you suspect the algorithm is learned by the enemy then they can potentially decode everything and you have to throw it all away and start again. And algorithms are hard to think up.
A better idea is to use a key. In a key based system, the algorithm is not secret, instead the secrecy is all condensed into a large random number called the key. The encryption algorithm takes the plaintext message and combines it with the key using some long series of mathematical processes to produce the encrypted message. In order to reverse the algorithm the recipient must also have the key.
Now the algorithm is not secret, so experts can examine it to confirm it is secure, and if the key is compromised, you just throw it away and pick a long new random number. Heck, use a new key every time you send a message, then even if a key is compromised without you knowing the enemy can only read one message.
That's keys. You also talk about passwords, which are different, and public keys, which are a special kind of key. Both are used to solve some irritating practical problems with using keys as part of a system for exchanging messages.
The first practical problem with keys is that since a key is just a big random number, humans find it very difficult to memorise them. If your system needs a person to remember the key and not write it down, then you have a problem. A password is a combination of letters and characters that a human can remember. Your system can use something called a key derivation algorithm that takes a password and turns it into a key. Password based systems are not as good as systems that just use a key, but it's a limitation of human beings, not much we can do.
So you don't really use a password to decode a message, you use it to generate the key and then use the key to decode the message.
The other practical problem with keys is called key distribution. Before I can securely send you a message we have to both know the key, so I have to give it to you. But I can't send it to you encrypted, because you don't have the key yet. And I can;t send it plain text, because what if a bad guy is listening in?
In many systems there is a way to exchange keys over a separate secure channel. For example, M can give Bond the key he should use before he sets out on his mission, while they're still safely in MI6 headquarters.
But sometimes this is not possible, especially over the internet, where we usually only have the internet to communicate over. So a new trick is required, public key cryptography.
In this type of system, I have two keys that are mathematically related. If a message is encrypted by one of the keys, it can only be decrypted by the other one. I call one the private key, and keep it secret; I call the other the public key, and tell everyone what it is.
Now you can send me a secure message by encrypting it with the public key. An attacker can listen in as much as they like, I've already told them the public key, but that's no good to them, only the person with the other, private key (me) can decrypt the message you sent.
For boring practical reasons, you typically only use public/private key once in a conversation, right at the start so you can safely exchange keys over an untrusted line, and then use a regular single key encryption method for the actual message. So you don't really use a public or private key to decode a message, you use it to safely swap a third key, and then you use that to decode the message.
Comment: Jumping into the comments to point out that of course Bond knows his OpSec and so uses codes,not ciphers. Or lets the local station do the encryption for him.
Answer:
To my knowledge, a key is a password used to decrypt a message.

The Key is built out of a Password Derivation function. The function (i.e. PBKDF2, or a repetetive SHA-256) is designed to take a notable amount of load. (i.e. 250ms)

The derived Key is more difficult to guess than the original password (i.e. defend against a rented cluster trying to brute-force your key)
The derived Key will more easily match the desired key size for your every-day block-cipher encryption.

However, the confusion comes in when it comes to the public key, is the recipient putting in the password to receive the message?

I had the exact question myself. It seems impossible to get a secure, public-use system, without the receiver getting the secret key ahead of time.
Symmetric Encryption is simpler. The same key is used for decryption and encryption.
Asymmetric, or Public-Key cryptography has one key that can only be used for Encryption, and the other for Decryption.
If you pass these keys in the right order, and combine that with a Certificate, then you can log on to your Online Banking account and your connection is secured against eavesdropping or impersonation.
(and, without the need for prior key exchange)
A common implementation of this is RSA, uses the 'power-of' operator.
If you take  a cheap calculator with Square and Square-Root buttons, and select 'Squared' (power of 2) on a complex number, then the result will be instant, as it is simple multiplication. However, 'square-root' on a complex (very long) enough number will have a small noticeable delay. This is because it is mathematically much more difficult to reverse.'
In RSA, we use power of X, where X is a huge (secret) number, so that reversing it would be quite expensive indeed. That becomes the key.
See: Is it possible to have a key for encryption, that cannot be used for decryption?
Working example: Is there a simple example of an Asymmetric encryption/decryption routine?

What exactly is a key in cryptography?


Self-conscious vs. self-aware

Question: I've often wondered why the words conscious and aware are synonyms, yet self-conscious and self-aware have such different meanings. Is there any reasoning behind this stark contrast in meaning between two compound words with such similar roots? Were their meanings always so different, or did usage cause their connotations to diverge over time?
Comment: [Self-conscious](https://www.dictionary.com/browse/self-conscious) has two different meanings, one of which is similar to self-aware and the other is not.
Answer: Their roots weren't that similar:

Aware :before 1100; Middle English,  variant of iwar, Old English gewær  watchful (cognate with Old High German, Old Saxon giwar, German gewahr ), equivalent to ge- y-  + wær ware
Conscious:1625–35;  < Latin conscius  sharing knowledge with, equivalent to con- con-  + sci-  (stem of scīre  to know; see science) + -us -ous; compare nice.

Conscious was derived later, and came from Latin. Aware was derived earlier, and was derived from Old High German.
That's the reason for their difference in meaning.
Comment: I would also add that conscious has another meaning of 'actively trying to do something'.  Self-conscious has a connotation of actively trying to perhaps present oneself in a particular way.
Answer: The word conscious deals specifically with mental state while the word aware refers to accounting for wares - anything material or mental than one owns which might include mental facalties.

Self-conscious vs. self-aware


Mediaelement.js support for Internet Explorer

Question: I am currently trying to use mediaelement.js as a solution for full cross browser support for my HTML5 videos. I used this Tutorial ( http://vimeo.com/44576115 ) in order to get the mediaelement working and it is working fine on Safari,Chrome,FF and IE9. I have tried it on IE8 and it is giving me a white screen without any video at all, I assuming this is a flash fallback failure ? I also need the video to have a flexible width so that It will fit in a responsive layout. I am starting to get totally lost on what I am running into as an issue. Could somebody please provide me with a "template" or a donation of tried and proven html5 video code which will work in all browsers including older IE browsers and IOS devices Ipad, Android etc? This will really help me a great deal and if anyone can help it will be very much appreciated.
Thank you very much.
This is my code for the video element, I have doubled checked all the directories to ensure correct linking.

<video width="640" height="360" controls="controls" preload="none">

<source type="video/mp4" src="darrel-vid.mp4" type="video/mp4" />

<source type="video/webm" src="darrel-vid.webm" type="video/webm" />

<source type="video/ogg" src="darrel-vid.ogv" type="video/ogg" />

<object width="640" height="360" type="application/x-shockwave-flash" data="mediaelement/build/flashmediaelement.swf">
    <param name="movie" value="flashmediaelement.swf" />
    <param name="flashvars" value="controls=true&poster=Darrel-poster.jpg&file=darrel-vid.mp4" />

</object>
</video>

Answer: In IE8 it uses the Flash fallback.
Please make sure, in the flashvars the path of the mp4 is correct.
Please post your code.


Estimating Negative Binomial Regression Model

Question: It is easy to estimate a Poisson regression model using the Newton–Raphson Iterative Technique as it only involves one parameter (mu). However, I am unable to understand how a negative binomial regression model can be estimated using the Newton–Raphson Iterative Technique, as it involve two parameters (mu and dispersion parameter alpha). Can anyone help me in this regard?
Answer: The Newton-Raphson technique can be applied to estimating multiple parameters. Instead of finding the gradient of the log likelihood with respect to a single parameter, you find the partial derivatives of the log likelihood with respect to multiple parameters in a vector. The second derivatives are in the form of the Hessian matrix. With the NB distribution both the mu and alpha parameter estimates are updated in each step of the process. Try googling "Newton Raphson multivariate" and you'll find many sites explaining the NR multivariate methodology.
Comment: Sir,I have work on your given advice but I am unable to find any literature depicting the estimation of NB model using multivariate Newton Raphson.Will you please help me


How do I create a Macro/short cuts in Eclipse?

Question: How do I create a Macro in Eclipse?
For example: I want the combination alt+s will print on the page
<code>//********************************************************************
</code>
Answer: In Java there's the option to create a code template. Like writing sysout + CTRL + space generates System.out.println() text.
Window > Preferences > Java > Editor > Templates
This option seems to be available for several other programming languages.
Is not exactly what you are looking for, since it works with written text but it's usable for your problem as well.
Answer: You should try Practically Macro
Answer: I do not think it is possible to do that on Eclipse, however you can use a simple AutoHotkey script:
<code>!s::send //********************************************************************
</code>
Alternatively you could also define a hot-string:
<code>:://*:://********************************************************************
</code>
Which would replace //*  with your predefined string...
Comment: where do I do that?
Answer: Something that you could use is a tool called Texter. It can't really do something like alt+s, but it can convert any text into longer something else (example: "thankyou" to "+{Tab}^{Home}^+{Right}^c{Tab}{BS}Thanks for the email, ^v{BS}." would grab the person's name in an email and say "Thanks for the email, (Name here)." )


How far apart are stars in a binary system?

Question: I'm wondering how far apart from one another the stars are in binary systems.
What is the distribution of the separation between binary stars? Are most of the binary stars very far apart like Sirius (8.2 to 31.5 AU)? Are there many stars in orbits even wider? Are there more pairs with grazing orbits?
Is there a database similar to exoplanets.org where I could see the distance between the pair of stars for all the binary systems we know of?
Comment: Proxima centauri is currently 13kAU away from the binary it's orbitting - that's about 0.2 light years. Whether that counts as a binary star for your purposes (technically, it's a binary of Proxima Centauri and Alpha Centauri A+B)... In any case, on such a scale, it's obvious that 5.5 AU is _not_ a far separation, as those things go :)
Comment: I guess I misread Wikipedia. Fixed it in the question
Answer: Distances ($a$) between binary stars vary wildly, from the order of the radius of the stars, to more than a light-year! The plot below (from here) shows a compilation of several surveys, with the color indicating the method by which they've been detected.
Separations are roughly normally distributed in $\log a$, peaking at a typical separation of tens of AU. The corresponding periods have median values of a few hundred years (e.g. Raghavan et al. 2010; Duquennoy & Mayor 1991).

As commented by Oddthinking, if stars are too close we are no longer able to resolve them visually (green bars). But we can still detect them spectroscopically (yellow bars): If we observe the blended spectral lines of two stars, we see the lines shift back and forth as the two stars orbit each other and their light is Doppler shifted.
On the other hand, if stars are too far from each other, their orbital periods of several thousand years makes it impractical to observe them orbit each other (we have only observed double stars for some 200 years); instead they're detected because they simply follow the same path through space — i.e. they have a common proper motion (blue bars).

As commented by PM2Ring, the fact that the two $x$ axes suggest a 1:1 correspondence between orbital radius and period seems odd — by Kepler's law, this also depends on mass. My random guess is that, because low-mass stars (which are most abundant) are poorly constrained (difficult to observe) and high-mass stars are rare, then most observed binaries are of the order of a Solar mass. If they're not too far from each other in mass, then there is an approximate correspondence.
Comment: @Oddthinking I'm not so sure about that... as they get closer together, the doppler signature gets more and more pronounced. That's why the observations down there are mostly listed as "spectroscopic".
Comment: Now i wanna see the radiative patterns of those $10^{-1}$ day pairs!
Comment: [Hi, an ignoramus here from HNQ, hoping this is appropriate] I am guessing it is harder to distinguish binary stars that are very close to each other as binary stars. Would that lead to bias in this chart because of sampling problems at the lower end?
Comment: @Oddthinking those kind of observational biases are generally a big problem in astronomy. And as Hobbs pointed out it is even not always clear in which direction they work.
Comment: @Oddthinking Good question! There _is_ a limit to how close stars can be and still be visually separated. In the plot, those stars comprise the green (and orange) bars. But stars that are very close are not detected visually, but rather _spectroscopically_ (yellow… well… curry bars I guess), i.e. by looking at the blended spectrum of the two stars. Then, over time, one can see the spectral lines shift back and forth, as the stars move perpendicularly to and along our line of sight.
Comment: @Joe Thanks for catching that error. I'll edit :)
Comment: The linked site says *"Superimposed on these results is the distribution of orbital radii calculated from Hipparcos or spectroscopic parallaxes in the Washington Double Star Catalog."* But I don't understand how that works. How can you equate a given radius to a given period when all of those systems have different masses? (I didn't read the full article, just the info near the chart).
Comment: @PM2Ring This is somewhat outside my comfort zone, but for spectroscopic parallaxes the masses _are_ known, since we know their spectral type.
Comment: Ok. But how can all the binaries with (for example) a log period from 3.5 to 4.5 have a log radius from 1 to 1.74, which is what the tallest bar in that graph seems to be saying?
Comment: @PM2Ring Ah sorry, now I see what you mean. Yes, those axes are somewhat misleading, because as you suspect, there _isn't_ a 1:1 correspondence between radius and period — it depends on mass (Kepler's law). My guess is that because low-mass stars (which are most abundant) are poorly constrained (difficult to observe) and high-mass stars are rare, then _most_ observed binaries are of the order of a Solar mass. If they're not too far from each other in mass, then there is an approximate correspondence. This is just my guess though.


why x(function setArr) is not being returned?

Question: pragma solidity >=0.5.0 <0.7.0;
contract Example{
    uint256[3] x;
    function setArr(uint256[3] memory y) public returns(uint256[3] memory){
        x=y;
       return getArr(x);
    }
    function getArr(uint256[3] storage z) internal pure returns(uint256[3] memory)
    {  return z;
    }
}

Answer: Short answer:
There is no syntax that will do that, by design.
Long answer:
The "why" of it relates to the EVM having different constraints than a CPU.
uint256[3] storage z is a storage pointer. That means it is represented by a single 32-byte pointer to a logical slot and the rest of the storage layout is implicit. It also means the function is inaccessible from outside the contract. Nothing outside can be trusted to refer directly to storage locations.
uint256[3] memory is a memory variable. These are transient and they don't persist after the function runs. This hints at the underlying fact that they live somewhere else. They're in the memory space, not the storage space.
So ... to get from storage to memory means copying data. It's not done automatically for (at least) two reasons.

Too much voodoo would discourage the design of efficient contracts. An idiomoatic approach here, or a loop if there are significantly more than three makes clear to the developer that work is happening. Reading, copying & writing.

You could:
function getArr(uint256[3] storage z) internal pure returns(uint256[3] memory x) {
  x[0]=z[0];
  x[1]=z[1];
  x[2]=z[2];
}

That makes it clear.
for(uint i=0; i<3; i++) { ... would also do it, but more expensively owing to the need to update and check i's state and jump around. That leads to the second reason which is, IMO, more fundamental.

A process like that has O(n) complexity, meaning the compute cost is directly proportional to the length of the array. Unbounded loops are a gotcha that can make a contract seem to work and then fail at scale. Iteration and recursion are powerful tools when compute power is essentially unlimited but they are deadly in a setting with hard caps on the computing resources available. That causes one to rethink what the contract should be doing. https://blog.b9lab.com/getting-loopy-with-solidity-1d51794622ad
That issue would not go away if the compiler had high-level grammar to help translate intentions into OPCODE. Everything in the EVN has a fixed cost for a fixed unit of work and this principle is also apparent in the high-level languages. In other words, if there was an explicit or implicit "copy array" function, it would be very dangerous.

Hope it helps.
Comment: The answer is not correct. The code does compile and it works as expected. The problem is that `setArr` is function called within a transaction so the returned value is not easily accessible off-chain (you have to execute a traceTransaction).
Comment: please can you expand on this as i have just started learning about blockchain? Thanks
Comment: Ismael has a good point. There is another problem if you are expecting to access return values while setting with a transaction. This is also important: https://blog.b9lab.com/calls-vs-transactions-in-ethereum-smart-contracts-62d6b17d0bc2


Quantum Cascade Laser vs Interband Cascade Laser

Question: What's the main differences between QCLs and ICLs in regard to laser characteristics?
Comment: For example lower thresold current density for ICL compared to QCL, but I really don't know much about the resaon why it's like that. It may be somhow connected with the fact that the operating principle in ICLs is based on interband transitions rather than intersubband ->like in QCLs.
Answer: The threshold current density is indeed lower in ICLs than in QCLs, mostly because of the large difference in carrier lifetimes (~ nanosecond in the ICL, ~ picosecond in the QCL). The lifetime is intrinsically short for the intersubband lasers because of the fast intersubband scattering (from phonons or interface roughness).
There are many other differences. Here are some of them: (1) the QCLs are much less temperature sensitive; (2) the QCLs use more stages and can generate higher output powers from a single ridge; (3) the QCLs are unsuitable for vertical cavities because of low gain for in-plane-polarized light, whereas IC VCSELs have been recently demonstrated etc.
Answer: QCLs are intersubband and do not depend on the bandgap. ICLs are cascaded but the lasing transition is from conduction to valence subband so they operate typically in the Near Infrared.
Answer: The active regions of ICLs are typically type-II quantum wells, in which their bandgaps are determined mainly by the quantum well layer thickness rather than the bandgaps of the constituent materials. Hence, the bandgap of an ICL can be tailored to cover the entire mid-infrared spectrum.


Is there a way to disable a specific JS script from a specific website?

Question: I want to disable a specific JS script from a specific website without disabling the javascript completely. Is there a way to do that ?
Answer: (Reference: http://noscript.net/faq#qa8_10)
After installing NoScript, open its option (by opening context menu on the small icon on the status bar/add-on bar, or through Addons Manager)
Go to Advanced tab. In that page, go to ABE tab. Under Rulesets, click on USER. Here is an example ruleset, put it in the textbox on the right:
# User-defined rules. Feel free to experiment here.
Site http://res.nimg.jp/js/ads.js*
Deny

I'm not sure how URL matching works, whether it uses regexp or not. Some examples on the FAQ does show regexp usage, but my example above seems to also match ads.js?foobarbaz.
Answer: Chrome has this functionality built in now, its comes under Request Blocking in the dev tools. This answer over on StackOverflow has a great description on how to use it.
Comment: but if anything happens to the SO answer, a fair bit of the utility of your answer goes away. A certain amount of duplication between sites is fine
Comment: Please quote the relevant sections from the linked answer.
Comment: I didn't see any point in unnecessary duplication. I would have to post the entire contents of the answer including the images, and if I did that then anyone looking for this answer would miss the comments and other answers to the question in stackoverflow. In reality that question is really a duplicate of this one, but is has much better answers than the ones posted here.
Comment: This should be the best answer, you don't need to install anything. Thanks!
Answer: You may use uBlock Origin in Chrome and Firefox:
https://github.com/gorhill/uBlock/wiki/The-logger#creating-filters
Answer: If you are using Firefox, you can also use AdBlock Plus to block all functions in a specific file. (Instructions below are for Windows.)

In the toolbar, click the AdBlock Plus icon, and select Open blockable items from the menu.
A window will appear, listing everything that ABP can block. You can scroll through the list to find the particular script file or you can type in the Search box to narrow the list down. Once you've found the file to block, right-click the file and select Block this item ....
ABP will create a new filter based on that file and will list several options for you:

The complete path to the file (www.domain.com/scripts/ascriptyoudontlike.js)
Any file in that subdomain (www.domain.com)
Any file in that domain (domain.com)
A custom rule that you can define; by default, this starts off the same as 1.

Click the radio button next to the first option and click Add filter. This will close the window and add that JavaScript file to the list of blocked items.

You may need to refresh the page to ensure that file is blocked.
Answer: If you're using Firefox, the NoScript plugin will allow you to do this.
http://noscript.net/
Comment: +1 - NoScript is exactly what you seek. As far as I know you'll need the Firefox browser to use it. Great extension.
Answer: AdBlock Plus does it but doesn't this concern a security risk?
In the real world disabling a JS might cause problems to an application (as for example an XSS attack by disabling the .js that checks for validation in user inputs) or anyway any check on the userside and not the server side.


Why do Signs Fall?

Question: My question in this post is, why do signs with large angles fall? For example, fold a piece of paper in half, set the angle between the two halves, and place it on the floor; it will stand or collapse depending on that angle. I currently believe that the only horizontal force affecting the sign is friction; which does not vary with angle, as friction is $F_n \cdot F_s$ and both are not related to the angle. Any help on this would be appreciated.
Answer: It is due to tensile internal forces (and the center of mass doesnt change position). And you are correct, the friction doesnt change. Look at the graph for the forces acting on the small element of paper in contact with the floor.
We have two equations to describe vertical and horizontal forces at equilibrium:
$N-mg-T\cos{\alpha}=0$
and
$F_r-T\sin{\alpha}=0$
From which you get
$\frac{\mu N}{N-mg}=\tan{\alpha}$
if $\alpha$ is too large, the equality no longer holds and the horizontal tension overcomes the friction.
Answer: Frictional force is horizontal. Use angle to get horizontal force component due to gravity on paper. That's plenty!
Answer: I believe a major factor in it is failure of the central pivot's friction to resist the larger torque generated by the longer lever arms.
So, yes, this is a matter of friction, but not only on the feet. What resists "first" is the friction of the central pivot. If that fails, then feet friction comes into play.

Why do Signs Fall?


Row-crop field boundaries

Question: I'm on the hunt for field boundary coordinates in the US in the form of GeoJSON, a Shapefile or any structured format that I can use to overlay on a map.
I've tried looking at the US Department of Agriculture but can't seem to find it.
Not sure I'm using the correct terminology for find such data.
Comment: That information is not considered public; there's actually handling regulations to prevent release.  It's unlikely you'll find an open source.
Answer: CLU isn't available to the general public. It's considered PII now.
None the less. It's doesn't cover all ground, just those involved in USDA programs. Plus, the boundaries don't always match up with what's actually going on the ground.
For example, a producer decides to crop one part of a field in beans and the other in corn. The CLU boundary may not reflect that split.
There is a data crop layer NASS produces. A raster product which covers all of the US.
Answer: When I worked at NRCS, we used CLU layers, which followed tracts of fields. I don't see them at http://datagateway.nrcs.usda.gov/. However, if this is a serious request for data and you are willing to put some time into it, you should give your local county field office (either NRCS or FSA) a phone call. They are usually happy to help, and if you ask to talk to the state GIS coordinator, they might be willing to help with coverage across the entire state (we restricted field office to county-level access). I don't know if they data is classified in any way. Again, if this is a serious enough request, reach out to those guys. They are always willing to help if they can (in my opinion).
I believe FSA maintains the CLU layers, but NRCS uses them for planning. The two branches are often entertwined in their GIS data.
FSA - CLU
FSA - CLU Examples
Answer: A little bit late but here is the link to the Cropland data layer that the NASS produces for the U.S.
https://nassgeodata.gmu.edu/CropScape/

Row-crop field boundaries


How can I know if my cat is in pain?

Question: When a cat is sick, it is often quite obvious to its owner, but sometimes it is not so clear. What if the cat was in terrible headache or suchlike? What are signs to look for when I suspect my cat is in pain, but is not bleeding, drooling, vomiting, walking erratically or showing other obvious signs?
Comment: I had an old cat who became very vocal and would just yowl. At first I thought maybe it was going deaf or was getting a little senile. Eventually a vet took his blood pressure and it was sky-high. The vet said the high blood pressure was probably causing headaches and he was yowling because he was in pain. We got him on meds to control his blood pressure and he did much better.
Answer: As Monica and Me123 have said, the big two signs of cat distress are:

hiding
changes in eating habits, especially not eating or drinking

Other signs I've seen with various cats include:

If the cat is injured, touching the area that's in pain will get complaints from the cat - depending on how badly the cat is hurting anything from crying to trying to bite to get you away from the painful place. This also happens with arthritis if you try to move the arthritic joint.
Any change in the cat's normal behavior. A normally standoffish cat who becomes very affectionate is likely trying to tell you something (I had this happen with a cat who was normally very aloof. She became very affectionate for a day or two, then went into hiding. At that stage she was in advanced kidney failure - she was aware she was failing and was 'saying goodbye').
seeking cool areas (normally cats will chase the warmest part of the house) can mean that the cat is feverish, especially if it sprawls out to get as much body contact as possible with the cool surface.
Inexplicable crying - a cat's distress meow is quite different from the normal talkative meow - particularly if the cat doesn't calm down with your voice or presence (an elderly cat that's having senility or disorientation issues is likely to calm in response to your voice, where one that's in pain probably won't).
Rapid weight loss or weight gain, particularly if there's no change in the cat's eating habits.
If you see a bluish tint to your cat's paw pads, nose (only works on cats with pink pads and noses, obviously), and tongue, the cat's breathing is impaired and there isn't enough oxygen in its system. The cat could be sprawled out panting (I've seen this in a cat with pneumonia - we got him to the vet in time, but the permanent lung damage he sustained took him from us when he was ten - the damage was something like emphysema and he ultimately couldn't get enough air in to sustain himself), or he could simply be not moving around much.
Comment: Assuming your cat doesn't mind being petted, that's a great opportunity to notice if there's any tension in its body. When I pet my cat, she immediately relaxes (assuming I haven't interrupted her in the middle of playing). If instead she remained tense, I would suspect a problem.
Answer: When my elderly cats were dealing with various serious conditions (kidney disease, heart disease), my vet advised me that cats try to hide their pain.  She told me to look for behavior changes, specifically:

changes in eating habits, especially loss of appetite or thirst (the latter is very serious and requires intervention)
hiding (my kidney-failure kitty did this in her last couple days)
listlessness

Other behavior changes may or may not be pain-induced; when one of my cats (who had previously been generally quiet) started yowling a lot, particularly in the middle of the night, I asked my vet about it and she suggested that senility or disorientation was more likely than pain.
Answer: My cat was once in pain, and I picked up the following things:

My cat was once noisy, but he suddenly got very quiet.
My cat started running away and hiding from me.

Also look for sores and listen in the night for fighting.

How can I know if my cat is in pain?


Select pixels brighter than X in a BW photo in Photoshop

Question: I would like to select areas which are brighter than X (X is determined visually).
Select -> Color range -> Highlights selects very bright areas, but it has no adjustments and it doesn't include some brighter midtones.
Select -> Color range -> Sampled Colors doesn't work on black and white photo at all.
Is there another method?
Answer:
Duplicate the layer where you want to select values greater than X, a safety precaution
Turn off the layers below the new layer
Double-Click on the new layer icon which will bring up the layer style window (see image below)
On the Blend If sliders find "This Layer", move the dark triangle slider on the left towards the right until you reach the cut off value, read the number above the slider (see image below)
Click OK

Now you have the pixels above the cut off value remaining. If you like you can also adjust the light triangle downward to exclude values above a certain point.
Answer: One idea:

Select your photo. Copy it on the clipboard.
Make a new layer, can be the photo itself or a pure color, that depends on what you need that for.
Make a layer mask and paste the same photo.
Modify the curves of the mask. Use the white point droplet and black point droplet. Depending on how close the values are you will have a more contrasted selection.
Done. That mask has the values you need.


Search for content type under multiple paths

Question: In SharePoint 2013 on premise, I have a search page with a search box where it is possible to search for items of a specific content type under a specific site. This works as expected.
<code>path:"http://path1" ContentTypeId:0x0100XXX*
</code>
But, if I also add path2 as the other site that I also would like to query for those content types, I get the strangest results.
<code>(path:"http://path1" OR path:"http://path2") ContentTypeId:0x0100XXX*
</code>
Everything seems alright until I enter a search word in the search box.
If I search for a word that I know does not exist in one of the sites, the search results bring up all the items with the content type under that site and for the other site it highlights the words in the items where there is a match.
I can also mention that this search page is configured to display all items of this specific content type when no search word is entered in the search box.
I suspect it is some kind of problem with the syntax I use in the query builder, but I have tried several variants without success. But the strange part is that the error only can be seen when a search word is entered in the search box.
Comment: Did you try ((path:"http://path1" OR path:"http://path2") AND ContentTypeId:0x0100XXX*)
Comment: Yes, it was giving the same result.
Answer: It seems for some reason that the search has been working properly without the {SearchBoxQuery} part when I just was searching one site. When I changed my query to
<code>{SearchBoxQuery} (path:"http://path1" OR path:"http://path2") ContentTypeId:0x0100XXX*
</code>
the search results are working properly when searching multiple sites.


Should labels in a figure be set in a different font face or font size from the body text?

Question: I'm writing a scientific text, which includes a labeled diagram. Are these traditionally labeled in the same font and font size as the body text, or in a smaller font size, or in a different font?
Comment: Hi. Welcome to GDSE. There's no such rule AFAIK, and font choice is subjective.
Comment: @BillyKerr I understand that everything is allowed, but I hope that there is knowledge and intuition that I lack that could guide this choice.
Comment: Look at some science papers. See what others have done, and use similar fonts if you like them.
Comment: Doing what always has been done traditionally is seldom a good idea; especially in a field as conservative as design / typography in science. So I'd actually recommend *against* looking what others have done as @BillyKerr suggests. Working on a more thorough and more constructive answer.
Comment: @Vincent - but if someone isn't a designer they may need help, and the work of others is as good a place as any to get ideas from, as a starting point. I also have the feeling from what I've observed of scientific papers, is that the designs are generally more conservative. This is not necessarily a bad thing.
Comment: There are many cases in academic publications that the writer does in fact not know how to make a good diagram that matches the overall article layout. So what they have is plot for application X and leave it at that.  But even if they could  there are reasons why the diagrams can not have same font like if diagrams are drawn and the thing is typeset by different people at different times. So it is okay if the diagram is a illustration on its own and does not follow conventions of the rest of your publication
Comment: Thank you @joojaa. I have the opportunity to match the diagram with the rest of the publication, what would you keep in mind when doing that?
Answer: As you can notice, there are different answers. This means that the word "should" does not apply.
Let me separate your question into several parts. Font-face and size. Although they are closely related.
Size
It is pretty obvious that size denotes hierarchy. There are some already defined. Chapter titles, section subtitles, and the body text.
The body text size is what defines the minimum size the superior ones can be.
Although some other sections have less hierarchy than the body text, like footnotes, there is a limit on what they should be, because of readability.
But also they need to be different so the normal flow of reading the main body is clear. A keyword is a flow.
Footnotes can be differentiated by size, as mentioned in other posts can be in order of 2pts. 11-9pts 10-8pts.
Diagrams
In diagrams, the theoretical size is delimited is also by hierarchy and readability.
But in reality, it is limited by space and tools.
For a diagram, it would be more important to have a consistent size to show the internal hierarchy inside the diagram itself, than comparing it to the main text, but maintaining a good redability.
Arguably the information provided by a diagram is really important, so try to keep it at least the same size as the body or at least the same size as the footnotes.
Font-face
Normally this changes in this is to provide differentiation, not over hierarchy but about context.
The basic change in font-face is using bold or italics, but normally these are reserved to be used inside the flow of the text.
A more "advanced" change is using the same font in different weights, extra bold, light, or different widths like extended or condensed.
And a change from sans-serif to serif is probably a more stylistic approach than hierarchy alone.

Spacing
You might need to use a different font in case you want a clear distinction between the diagram and the flow of text, but in reality, this distinction and isolation should be given by well-defined spacing.

So: "should" the font be different? No. It might.

In practice, I suppose scientific papers traditionally depended on what Microsoft Word has defined by default.
For decades it had Times Roman as the body default. And Powerpoint could have Arial as default...
LaTex also uses a serif font as default.

Another reason, I suppose, scientific papers keep those "archaic" design choices might be because 1. They want to look "timeless" or 2. They do not want to look very distracting, disruptive, or less serious.

As a recommendation, a modern approach would use a sans-serif font for both, text and diagrams, and choose one font that has enough internal styles and weights to make the differentiation you need.
I agree that Lato and Open-Sans are good choices, but ONLY if your paper is going to be distributed in PDF format with fonts embedded. If it is going to be distributed in Word format you need to use standard fonts, like Calibri, Arial, or Times... Times and Arial look old.
Unfortunately, Calibri font does not have a wide selection of weights.
You can use Verdana for diagrams, that have a good readability in small sizes if you have that constraint.

P.S. If by "label" you mean "Figure 1" and "Figure 2" text use the same size using different weights or italics.
Comment: Thank you very much! By "label", I meant single words in diagrams, not the figure caption.
Answer: It... Depends. There are two different questions to answer here, and they are pretty distinct:

What is traditionally done for the typography of labels in a scientific diagram?
What is a good, legible, and reader-friendly rule of thumb for typography for the labels in a scientific diagram?

The answers to these two questions are as different as the answers themselves.
Question #1 is hard to answer without becoming rude, but I'll try: Typography, and design in general, is traditionally not a concern in science. There are few traditional rules, and those that exist are based more on being grandfathered in rather than yielding good and legible results. I'll just be bold (pun intended) and say that following traditional typography and design rules as they exist in science is a bad idea. Your message will not stand out, will be hard to parse or even decipher if you do.
Disclaimer: this answer is a bit jaded and exaggerated, but it's a rather accurate reflection of my experiences as a designer in science.
Question #2's answer consists of a few points.

Choose a readable sans serif typeface (as per Julian's answer). Good candidates are Roboto, Lato, Open Sans or Montserrat (all links to Google Fonts). If the body text of your article is set in a sans serif, choose the same typeface.
Ideally, you'll want to make your labels of roughly the same font size as your body text, or maybe a bit smaller. If you go for smaller, make sure the point size differs by at least ~20%, so eg. 8pt labels next to a 10pt body text. Normally, you'd want different kinds of text to have sufficient contrast to help differentiate between their functions. But a reader confusing labels with body text is highly unlikely, so those being of the same font and size is possible, if not ideal. You may want to give your labels a colour or make them bold or italic if you end up choosing the same size as your body text.
Your labels should never be smaller than ~8pt (slightly depending on the typeface and font variant). Smaller font is hard to read, especially for supervisors and peer reviewers approaching retirement age.
More important than the exact size, is being consistent with that size. All labels should have the exact same size (and font, and colour), unless there is a hierarchy among them. In that case, use (distinctively) different typography to reinforce that hierarchy.
Do realise that you will not always have control over the relative size of your diagram in relation to your text, especially in traditional scientific publications and magazines. Therefore, it's safer to err on the side of large and legible for any text you inlcude in your diagram.
Leave enough white space around your labels to prevent overcrowding the diagram. If necessary, use pointer lines.

tl;dr (too long, didn't read)
Traditional typography choices in science kind of suck, so you may want to do your own thing rather than follow convention. Choose a sans serif typeface, and match your body text typeface if it's in sans serif. Exact size is not hugely important, as long as the difference between body text and label is obvious. Don't go below ~8pt, even after the diagram is shrunk, eg. to fit in a magazine.
Comment: Thank you, very helpful list!
Answer: For diagrams it is in general best to go for a well-readable sans-serif font. If you have a serif or more stylistic font it makes sense to use a different font for diagrams, otherwise use the same.
The amount of information on diagrams often forces you to have small type.
Comment: If the amount of information in a diagram forces the labels to be small, it's a bad diagram. /unpopularhottake
Comment: Not nessecarly. Depends a lot on the content of the diagram. When you are talking simple flowchart – yes agree. If you have more complex time/money chart for instance you don't want the months label to be too big...
Answer: You may be asking in the wrong forum. Designers are paid to design, to be original. They devalue tradition, which is just what has worked reasonably well in the past. And reasonably well is all you need. The content of your text is far more important than its appearance. This is not (I hope) advertising. The only real constraint on appearance is that it not be distracting.
If you have in mind some specific publisher, they will have a house style. It will be OK. Follow it. It will specify most things like font size for captions.
Figures themselves are more of an issue. The possibilities are too numerous to be covered by any house style and, too often, are produced by some software with whatever the default options are. If those options are customizable, consider them carefully. Do not make labels too small. Do not overcrowd graphs. DO look at what others do, and copy the ones that you can understand. You cannot control how the printer will size and position your figure. Prepare for the worst case.
Comment: Good Designers do not devalue tradition, often even embrace tradition. They should know the rules what is 'allowed/best'. While its true they sometimes bend/break these rules in order to make it more original. But designers also are able to give non-designers simple best-practices guidlines that work in 95% of cases.
Comment: True, I spoke in anger because several here have devalued tradition. And scientific typography is one field where obtrusive novelty is simply abhorrent, not to mention self-defeating. Non -designers need only follow reasonably good precedent in their drafts.


Tag synonym request: [trenched] → [iron-brigade]

Question: Trenched by Double Fine is going to be renamed Iron Brigade. I'd like to request that trenched be made a synonym of iron-brigade when the update goes live later this month (September 2011).
Answer: This is now complete.
(we like to have answers on these so they don't show up as no answers..)


How do I send a Minecraft Resource Pack to someone

Question: I play on Windows Bedrock Edition and I have made a resource pack I want to send to a friend but I don't know how to, I've searched it up on google but i can't find anything on it
Answer: Assuming the resource pack is in a folder:
Right-click the folder and compress it into a .zip archive. Place the folder in a Google Drive, and have them download it and put it in their Minecraft/games/resource_packs folder.
Assuming it's a .mcpack or .zip:
You can just send it to them and have them manually extract it at the source. If it's a .mcpack, they can simply open it in Minecraft to self-extract.


Dual boot grub rescue

Question: I deleted a partition. When i restarted my computer i had an interface showing this message: "error no such partition.
Grub rescue>"
I don't know if the partition i've deleted was the one where ubuntu were installed (if so im dead. All my important projects are inside) or it was only storing the grub files.
Note that i have a dual boot.
Who can please help me save both my linux and windows please!
Comment: May be best to see details, you can run from Ubuntu live installer or any working install:
Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
https://help.ubuntu.com/community/Boot-Info But if you need to restore partition then testdisk may be able to do that. http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step But did you miss this before making any major change? discussion of alternatives/strategy backups
https://help.ubuntu.com/community/BackupYourSystem
Answer: Hum,  not really a question, so this is not really an answer. Don't despair. Get an external USB harddrive with a lot of free space. Use an Ubuntu live CD or USB key to boot your computer, then make a full image of your hard drive on the external harddrive. for example, use the instructions in the answer to this question (use dd, not tar). Then, and only then, use tools like Testdisk to recover the deleted partitions.
If you are so unlucky that testdisk can't recover the lost partitions, PhotoRec can still be used to recover some of the files. This is however a last resort, as photorec cannot restore file names and directory structure, nor can it make difference between a file that had been deleted and a file that was present at the time you deleted the partition.
Comment: @sudodus you edited my answer and added photorec. Photorec has **nothing** to do with testdisk. So don't let them side by side, in the same sentence. Your edit was **misleading** in the sense that it let people think testdisk and photorec are the same kind of software. I let the photorec suggestion, but with **some more explanations**. OP did not format his/her drive. The partition was deleted. testdisk is the solution, not photorec.
Comment: You are right. I should have not only added it, but also written an explanation. (For me testdisk and photorec are a couple. First try with testdisk, and if it fails, resort to photorec. They are available from the same website, https://www.cgsecurity.org/).

Dual boot grub rescue


Calling "transferFrom" from contract

Question: Solidity noob but have looked around and cannot seem to find an answer to my specific issue.  I am sure I am overlooking something really obvious but need help.
I am working in Remix using the Injected Web3 environment.  I have successfully deployed a test contract from the injected wallet (using https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol) and I can see the 1 trillion tokens in that wallet.  So far so good.
I have a second contract and am just trying to set up some functions so I can:

Approve an allowance for the contract to spend this token on my behalf
Send the token on my behalf (to itself, in this case)

The code I have is:

    // grant allowance to contract to spend 'amount' on behalf of caller
    function approveToken(uint amount) public payable {
        token.increaseAllowance(address(this), amount);
    }

    // send 'amount' from caller to contract
    function sendToken(uint amount) public payable {
        token.transferFrom(msg.sender, address(this), amount);
    }

    // return balance of 'token' owned by caller
    function getTokenBalance() public view returns(uint256) {
        return token.balanceOf(msg.sender);
    }

    // return 'token' allowance contract can spend on behalf of caller
    function getTokenAllowance() public view returns(uint256) {
        return token.allowance(msg.sender, address(this));
    }

approveToken executes without any error
getTokenBalance works fine (shows the tokens)
getTokenAllowance returns 0
What I think is happening is when I run the sendToken function from remix my wallet is the caller, not the contract.  So I am essentially checking whether I have given myself an allowance to send this token, and perhaps that is what is tripping things up.  So it seems to me I need to make sure the contract is what is calling the sendToken function as that is the 3rd party given an allowance.
But I am lost, any help would be appreciated.
Answer: Sorted, was being stupid and calling the tokens approve() function via the transfer contract and not on on the token contract directly.

Calling "transferFrom" from contract


Who first suggested that the state should hold the monopoly on violence?

Question: I'm reading Stirner's The Ego and Its Own and I'm struck by how modern some of the ideas he's presenting are. In particular, he defines the state as the group of people with the autority to do violence to members of a community. Is he the first person to say this? If not, who said it earlier?
Comment: See [Wikipedia's Monopoly on violence](https://en.wikipedia.org/wiki/Monopoly_on_violence):"*The monopoly of the legitimate use of physical force, also known as the monopoly on violence (German: Gewaltmonopol des Staates), is a core concept of modern public law, which goes back to Jean Bodin's 1576 work Les Six livres de la République and Thomas Hobbes' 1651 book Leviathan*". [Stirner](https://en.wikipedia.org/wiki/Max_Stirner) is often cited as a precursor of nihilism, individualism, post-modernism, and  anarchism, very modern indeed.
Comment: The State. That's who first suggested the idea. If your question is who formally wrote down what had obviously already been going on for a long time, then the Wikipedia article would answer that question. But historically, when did people assent to the idea that the State may commit violence on an exclusive basis? Something like law and order coming to Dodge, but even among cave dwellers it must have been clear that the leader of the tribe had more rights to violence than others did. Is this hierarchy of the legitimacy of violence genetic?
Comment: Ah, I knew I was phrasing it wrong! Monopoly, not privilege---if I could have remembered that, Google would have been more fruitful. Thanks!
Comment: This sounds related to the concept of Night-Watchmen state and to Social Contract theory.
Comment: More details into [Jean Bodin](https://plato.stanford.edu/entries/bodin/#4) and [Hobbes's Political Philosophy](https://plato.stanford.edu/entries/hobbes-moral/#LawNat) and [Sovereignty](https://plato.stanford.edu/entries/sovereignty/#2).
Comment: How do you define modern?
Answer: In political science, the person who defined (rather postulated) the nation state as the territorial monopoly on violence is attributed to Max Weber.
Weber's own precise expression is "the monopoly of the legitimate use of physical force within a given territory" (in his Politics as a Vocation).  By legitimate, Weber means the successful execution of power monopolization to the effect that the monopolizing entity has the military force, and the people within the territory acknowledge only this entity's having the power and obey its commands. That is, as a sociologist, Weber did not attach any normative value to legitimacy. Under this interpretation, there is no moral difference between the nation state and mafia. The intellectual tendency in political science and sociology (e.g., Mancur Olson in Power and Prosperity) in fact is that the origin of the nation state is the last mafia standing. That is, the one that was able to eliminate all other competing mafias and to create a stable method of succession became the essential constituent of the government. It is political philosophers who have attributed normative value to legitimacy.
Based on this background in academia, Max Weber should be the guy you are looking for. There are two problems however. One is that Weber's definition comes after the publication of Stirner's The Ego and Its Own, which was published in 1844: Weber's was published in 1918. A way to solve this problem is to indicate that it is the historical common sense that only the state has the right to violence. That is, even peoples in antiquity understood the violent yet justified power of the government (e.g., who killed Socrates?) If any entity grasps a person with force and puts the person in a tiny room without the person's consent, we call it kidnapping; if the government does the same thing, it is called retributive justice.
Second, your phrase of "the state should hold monopoly on violence" is incorrect in that no scholars meant monopolization of violence prescriptively. They meant it as a descriptive, defining idea of a nation state, as "the state holds monopoly on violence.
Comment: didn't hobbes prescribe it??
Comment: What I am saying is that the guy who coined the term  'the territorial monopoly on violence' is Weber. Ideas similar to it had existed thousand years prior to him. Leviathan (1651) is preceded by the Prince (1513), which is further preceded by Aristotle's the Politics (in the chapter on "How to prevent revolution?")
Comment: You do not need to apologize. Knowledge grows by someone like you who says "Objection!"  Anyway SE does not like us chatting in the comment format.
Comment: oh ok, stupid me, sorry
Comment: @user3293056. Scholars have interpreted Leviathan's absolute power as descriptive power, not normative power.  Could you explain why it might be viewed as normative power?
Comment: i just believe that's what my lecture handout said
Comment: I would love to hear a new interpretation of Hobbes! It would be great if you take some time and formulate your understanding in the answer form in SE. If not, could you at least indicate who the lecturer is or which book you are using. I could look it up by myself.
Comment: if it's a new interpretation then i must be wrong, and i apologise
Answer: Thomas Hobbes in his book Leviathan promoted violence by the sovereign, for order. Machiavelli who advised princes in his book The Prince, probably did the same as Thomas Hobbes.
Answer: I know the question is old but for anyone who happens upon this later, Weber attributed the observation to Trotsky at the Brest-Litovsk negotiations of 1918. Trotsky in turn attributed the observation to Lenin. The closest thing I've found to the monopoly idea in Lenin's published works is:
"At the decisive moment in the decisive point one must deploy the overwhelming superiority of forces--this 'law' of military success is also a law of political success, especially in that bitter, seething class war, which is called revolution."
Vybory v uchreditel'noe sobranie i diktatura proletariata:The translation is my own.


What are the current known implications of the complexity of Integer Factorization?

Question: According to my limited knowledge we know that since Integer Factorization lies in the intersection of NP and co-NP it cannot be NP-complete unless NP=co-NP.  However, do we know any other implications yet- like if P != NP, does this mean that Integer Factorization is necessarily not in P?  Conversely, if Integer Factorization is in P, does this imply anything about the polynomial hierarchy?  Thanks.
Comment: Not 100% sure, but I think the gist is that we don't know much. The fact that primality testing is in $P$ with such a high exponent has led some people to belive that factorization might be in $P$, but I don't actually have a reference for this, I just remember hearing it somewhere, so I could be wrong.
Comment: @jmite, I don't think anyone conjectures that factoring is in $P$.  You are right that we don't know much.
Answer: Before answering your questions a distinction has to be made, when talking about $NP$ completeness we are talking about the decision problem not the function problem, which is given an integer N and an integer M with 1 ≤ M ≤ N, does N have a factor d with 1 < d < M.
So answering your questions in order, Since integer factorization is not known to be NP complete, $P \neq NP$ would not cause it to automatically not be in $P$ since quite often things that were thought to be in $NP$ are moved to $P$, only an $NP$ complete problem would be excluded from being in $P$. For the second one, again since it is not $NP$ complete a polynomial time solution to it will not effect the hierarchy for the same reason as before.
As an extra note, the actual location of factorization in the hierarchy is unknown, we know is is $BQP$, $NP$, $co-NP$, $FNP$ and $UP$. It may end up being $NP$-Intermediate, but no one knows for sure.
Comment: Thanks.  Although I'm a little confused by your answer- did you mean to write "not _known_ to be NP-complete"  rather than just "since integer factorization is not NP-complete".  Wouldn't your statement imply P != NP since otherwise all languages in the polynomial hierarchy are NP-complete (i.e. in P)?
Comment: If you really want to get technical then yes, it is not known to be NP complete, also it is not believed to be. Current thoughts say that if $P\neq NP$ then it is not in P, NP complete, or co NP Complete. I'm not sure I follow on how you reached your conclusion though. Even if $P=NP$ not all problems would be in what was previously the NP complete category.
Comment: We don't actually know that factoring is not NP-complete. If P=NP, then it trivially is.
Comment: This is just a question of semantics in speech. Until you can show something to be NP complete to state that it is not is logical. Otherwise we would have to preface literally ever run time statement with it, such as, we do not know if checking if a number is even is NP complete.


How to convert a wordpress site into a typo3 site?

Question: I already have a wordpress site i am trying to convert it into typo3. But i cannot find any help or tutorial regarding this pls someone help me?
Answer: I am afraid, there is no easy converter or so for this. Typo3 is one of the more powerful, but also way more complicated cms out there.
The whole way Typo3 works is completely different.
So I am afraid you process will be creating the new Typo3 site in the image of the old site - then have a decent cut'n'paste orgy.
You might have a look in the Typo3 Extension Repository if there is any extension that offers to import a Wordpess XML export.
Edit: See if these help you in any way
http://typo3.org/extensions/repository/view/timtab_import_wp
http://typo3.org/extensions/repository/view/gl_wordpress
http://typo3.org/extensions/repository/view/ws_wordpressgrab
Answer: Unless you have some knowledge of TYPOscript, you might have to start your website from scratch or have a professional handle the conversion for you.
To avoid copy/pasting, you can try this tutorial, but it still won't work for design and extensions.


Dominant Eigenvalues

Question: I'm trying to understand dominant eigenvalues and I found this website that has a explanation of it (Definition 9.2). In the example, the power method is used to find the dominant eigenvector which correspondes to the eigenvalue of 1.
When I calculate the eigenvalues and vectors of the matrix in the example, I got this result:

The first line are the eigenvalues and the second row the eigenvectors.
As you can see, the eigenvector that corresponde to to the eigenvalue of 1 is
<code>{-0.577, -0.577, -0.577}
</code>
If I calculate the powers of the matrix, I find that after M^9, it converges as shown in the website
I don't understand what is the difference between the eigenvector that I found that corresponde to to the eigenvalue of 1 and the eigenvector that is found after elevating the matrix many times, and that the website described also as the eigenvector of eigenvalue 1.
Answer: What do you mean by "the eigenvector"? For each eigenvalue, there are infinitely many eigenvectors, and you typically get a basis as "the" eigenvectors.
From your post, it looks like the general eigenvector for $\lambda=1$ has the form $(t,t,t)$ and you obtained the one with $t= -0.57735$. But other values of $t$ lead to other eigenvectors, and if I remember right, the power method produces a probability eigenvector, thus in this case $t=\frac{1}{3}$.
P.S. Also note, if you are reffering to the first 3x3 example on that page (it would had been very helpfull if you included the matrix you calculated), you should note that they find the eigenvector for $**A^T**$. In that example, it is trivial to see that $(t,t,t)$ is an eigenvector for $A$, but they don't calculate the eigenvectors of $A$!
Answer: Imagine someone has a list of numbers, known (to that person) but kept secret. Now imagine you have the ability to do some limited manipulation of those numbers and extract some information from the person about this set of numbers. You can ask that someone to alter every number in the same way by raising them to a power. Then you can ask that someone to assign each separate number to a specific (to that number) vector. The information then that you can get is the vector sum. If each but one number is smaller than unity in magnitude, they (the small numbers) will in the power exponential become small and their corresponding vector is scaled to a tiny bit. The number that is close or equal to one (or really just the largest in magnitude) will dominate, and the vector corresponding to that number will be apparent.
Now imagine all that again, but the person with the list of numbers is actually a matrix, the list of numbers are its eigenvalues, and the corresponding vectors for those numbers are the eigenvectors. That is what is called the power method.

Dominant Eigenvalues


Reduce block time

Question: I was wondering about block time and block size. Why are they defined the way they are? Is it possible to reduce the time between two blocks without changing the consensus mechanism? What would happen to the current consensus if we wanted to lower the time between two blocks?
Answer: There is a brilliant explanation about why was the decision of the default Substrate block time in this previous StackExchange answer: What is the possible minimum block time?.
Substrate is highly customizable, so yes, is possible to reduce the time between two blocks.
See these examples:

How to configure polkadot + parachain locally to validate parachain block each 6 sec?
Why my solo chain block time is 12 seconds when set to 6?

And just as an example about how customizable is if you want to change the consensus mechanism: How can I make my node generate blocks only when they receive transactions?
About your question what would happen to the current consensus if we wanted to lower the time between two blocks, I get this quote from the Shawn's answer I shared above.

Testing and benchmarking of your Substrate network will be the only
way to really determine how low you can safely get your block time.
Comment: Nice, thanks ! :)

Reduce block time


Visiting Andorra from Barcelona

Question: Can I  go to Andorra for few days while visiting Barcelona with a multi entry tourist Schengen visa issued from the embassy of Spain in Egypt? Or do I need a letter?
Answer: From wikipedia:

Andorra has stayed outside the Schengen Agreement and maintains border controls with the EU. However as travellers to Andorra have to pass through the Schengen Area, and Andorra does not issue any visas, but accepts Schengen visas, Andorra is in practice a virtual part of the area. Third country nationals wishing to visit Andorra need a multi-entry Schengen visa, since to leave Andorra they must enter the Schengen area a second time.

So in short, yes, your multi-entry Schengen visa should be sufficient to enter Andorra and then to leave Andorra, re-entering the Schengen area.
Comment: The Wikipedia quote contradicts itself.  If you need a multi-entry visa to get back out of Andorra, then Andorra is NOT a "virtual part of the area."  In practice, your time in Andorra will be treated as being in Schengen, even though it legally isn't.  The reason is that you will have no proof that you entered and stayed unless you put a lot of effort into obtaining such proof.

Visiting Andorra from Barcelona


How can I sort photos/videos by its "Date modified" on Windows?

Question: I used phockup to sort photos/videos from my phone's backup. A lot of them ended up in the "unknown" folder since they don't have "date taken". Now I want to sort files from "unknown" by their "date modification" to folders where my sorted files are (e.g. 2023/January/01-January). What should I use?
Answer: One possible solution is to use XNView MP. When you are in browser mode click icon like two arrows and select your sorting wishes.

Then select photos by desired group and move them with drag and drop.
Or use Alt+M to move them in folder (the folder will be created if not exist)
Comment: That's good but I'm looking for something automatic
Comment: @janlu, maybe you can check here: https://softwarerecs.stackexchange.com/
Answer: You can use exiftool for this, with a commandline something like this:
exiftool '-Directory<FileModifyDate' -d c:\target\%Y%m%d -r c:\source

This uses the file system modify date. Use ModifyDate if you want to use the EXIF ModifyDate.
You can use exiftool to list all EXIF tags your files actually contain.
See strftime for the date format options to cobble together a directory name to your wishes.


SharePoint 2010 debugging issue

Question: 4 team member is developing on a server. Now all 4 of them are debugging code for separate modules simultaneously.
If one starts debugging others get trouble. How to solve this issue so that both can work simultaneously?
Comment: any idea on this?
Answer: Development is best performed on one server per developer. The four can develop without interfering with each other. When their done, upload solution to TFS and use a separate build server to be sure it always builds.
Answer: You can ask each team member to take the local copy of the code from server and perform the operations of debugging. If all work simultaneousy, then they will get problems not only in debugging but in deploying the solutions.
So better to take the latest code from TFS, and make a local copy and go offline and then work.

SharePoint 2010 debugging issue


How does Donald Trump shut the government down?

Question: What eludes me is how the president is able to shut down the government, and why nothing has been done about it.
Comment: What do you mean, "why nothing has been done about it"? There were multiple negotiations during the shutdown to try and work out a deal to resolve the impasse.
Comment: Sorry, what I meant by that is "why hasn't this been fixed so this doesn't happen again."
Comment: @ThisIsNoZaku Very close, the difference being that Congress can refuse to accept a budget and the President can veto it, and that answer is from 2014 where apparently Congress didn't accept a budget, whereas this time it was the veto of the President. Of course, the effects are then the same. And the only solution is to convince Congress in 2014 / the President now to change their mind.
Answer: The US president can veto budgets of the federal government. That means, some branch of the government doesn't have any money. If they don't have money, they can't pay their employees. If they can't pay their employees, then all employees that are not absolutely essential are sent home without pay, and the others have to work for free.
Why is the US president able to do this? Because that's what the US rules are like. Can anything be done about it? As long as the president vetos these budgets, nothing can be done about it legally. The only thing that can be done is to somehow convince the president to give up his veto.
So how was Trump convinced to give up his veto? There will be many reasons. One, there are now a lot of people who will never, ever vote for him as president again, and they were getting more. Calling employees "patriots" for working for free probably didn't go down well with them, and recommending they take out loans to feed their kids didn't go down well either.
Two, many industries are suffering, and they put pressure on Republican politicians to change Trump's mind. For example, I'm told the fishery industry had problems because they can't get permissions that they need to go fishing. Airports have problems. Essential workers who are not paid suddenly get ill and the work isn't done. In two months I'd bet every single unpaid government worker would stay at home because of the flu.
Three, the area around Washington is suffering economically. There are hundred thousands of people not spending one penny that they don't have to spend. No new cars, only the cheapest clothing, only the cheapest food, to make your money last longer. That hurts the economy. And that creates complaints against Trump.


Reuse JSE checked exceptions as unchecked

Question: Actually what i'm doing in my code base is duplicating already existing java checked exceptions like MalformedURLException.class by keeping the same exception name while inheriting from RuntimeException.class . Sincerly,i did not find a better way.
I found that really bad,because i've now nearly 8 exceptions duplicated just because, in my case, i can't recover from theses types of exceptions and i don't want to throw them from each level until they reach the higher level as it would make code maintainability a nightmare.
Frankly, i think that oracle/sun should have thought about this case of re-usability and make the type of exceptions flexible and chosen at the moment of throwing, something like the following instead of relying upon exception's parent :
throwChecked new MalformedURLException();

IMO RuntimeException.class and Exception.class both should be uncheck exception and it is up to the developer to choose how it'll be thrown.

so my question, did i miss something in my case and analysis ?
and does exist a better approach without duplicating?

Best regards !
Edit
Note also by duplicating theses exceptions, i found myself obligated to cover all the branches of my classes hence cover all the created exceptions too if i want to have a good coverage.
Comment: Why do you need the checked version of them?
Comment: @max630 i don't need the checked version of them,i'm interested in reusing them in a unchecked way, because in my case,when i'ill throw them,i don't want to force my clients to catch them.
Comment: Ah they are not yours. I see  now
Answer: Checked exceptions are pretty much unique to Java and while they can have some value, it's really difficult to know when an exception should be checked or not at the time you are writing an API.  Your idea is interesting but unless you write a new language you'll need to deal with them as they are.
Your motivation to use unchecked exceptions instead of checked in cases where you can't recover is completely valid.  I would probably not duplicate the names of the exception classes, however.  There's nothing inherently wrong about it but it could be really confusing to other developers especially if they are used to Java.  For example your stack traces will look weird if you capture the cause exception because the exception name will be the same (aside from the package.)  You will also (I think) have to use the fully qualified class names in a lot of places which can really make the code ugly.
Instead what I tend to do is create a number of RuntimeException classes that have more names like ConfigurationException or UnrecoverableExecutionException or whatever makes sense in the app.  These take a cause parameter which accepts the original checked exception so that the full stacktrace is maintained.  This also gives you the opportunity to add more error handling code into these exception classes to do things like capture the context around the exception.
Comment: This is what I would have answered. This use case is why exception chaining is so useful in Java. Just wrap and throw!


Is it possible for smaller laser beams to merge into one large beam - I.E, the Death Star?

Question: In Star Wars, 8 laser beams fired by the death star merge into one large beam. Is this possible? It seems intuitive if you replace the laser beams with something like a bunch of baseballs (momentum in opposing directions cancel assuming your collisions are inelastic, leaving you with momentum in only one direction), but can the same thing happen with photons? What about sub-particles, like protons or neutrons?
Answer: Visible-light photons (like the photons that make up the Death Star's laser) don't collide with each other and scatter like baseballs do. They simply pass through each other. Other particles, like protons and neutrons, do scatter off of each other.
To make the Death Star laser-merging system work, you would have to have the laser beams focused on some sort of object that would interact with the laser light. The object could either absorb and re-emit the light in one direction (like using the eight lasers as the power source for an even more powerful laser positioned at the original lasers' intersection point) or refract the light (using some sort of extremely long focal-length lens). Either way, you would need some object positioned at the intersection point of the original lasers.
Photons with energies much higher than visible-light photons occasionally do scatter off of each other, in a process known as "light-by-light scattering," but this is very rare, and you'd be hard-pressed to manipulate it in a way that would result in a particularly strong beam.
Answer: Yes. But it isn't as easy as just bringing the lasers together. The must be in phase with one another or else you won't get a sharp beam coming out.  This is just what they are planning to do for breakthrough starshot.
https://cosmosmagazine.com/space/space-lasers-and-light-sails-tech-behind-breakthrough-starshot
Comment: This doesn't appear to be the same situation. All that is needed in Breakthrough Starshot is focusing the lasers onto an object, which is only half of what's being asked about. The Death Star situation has eight lasers focusing onto a point _and then emerging as a single laser beam_.
Comment: Actually, Project Starshot is much more complicated than that.  The lasers in the PS array need to have very precisely controlled relative phases, in order to perform as a single coherent beam with a 10 mm diameter.  Without that initial diameters the beam can't come to a two- meter diameter focus many millions of km away from the array.


A good resource on the Radon-Nikodym Property in reflexive Banach Spaces?

Question: I'm looking for a good resource that builds the theory of the Radon-Nikodym Property. I'm not particularly interested in the measure-theoretic characterisation; I'd like the geometry of Banach Spaces version, involving strongly exposed points of convex sets. If possible, I would also like the proofs to concentrate more a geometric approach over a convex/variational analysis approach, though this is not a deal-breaker. Thanks in advance.
Answer: Chapter 5 of Geometric Nonlinear Functional Analysis by Benyamini and Lindenstrauss is the best geometrically-minded resource on RNP that I know.
Comment: Thank you. I have one follow-up question. I'm reading through Theorem 5.11, at the bottom of page 106. I don't understand how Baire Category Theorem is being used. Do you know which BCT is being used, and how?
Comment: Never mind, I figured it out.


Framing a Page from a Holy Book

Question: Suppose you had a single page from an old Tanakh or rabbinic book. Would it be permissible to frame and mount the page on a wall?
Comment: what is your concern that it shouldn't be ok to do?
Comment: @Dude It might be perceived as disrespectful, especially if it has the name of Hashem. Also, I understand that some will not leave a holy book open, and this is a similar case.
Comment: I don't see how this is like leaving a book open. Not only that but a gram is most often considered to be a form of honor for whatever is put in it bc of the added protection especially if it is a beautiful frame
Answer: During aliyah le'regel the cohanim would draw back the paroches to show the aron ha'kodesh and say, re'u chibaschem liphnei ha'makom ke'chibas zachar u'nekevah.
See your belovedness before Hashem like the love between a man and a woman.
Given that framing the page shows its endearment and also given that the kedusha of the page is less than that of the aron ha'kodesh it would seem from this mishna that there is no concern about disrespect by making a show of holy judaica.
Comment: Perhaps doing it all the time is different from doing it every few months for a specific purpose?
Comment: (1) Can you bring a cite of a source for what you say in the first paragraph? (2) I find it a little hard to believe that anybody, besides the _Kohanim_ at work there, could see much of anything of the _Aron ha-Berit_, with it being in back of the _Heikhal_, and _Mizbach ha-Olah_ standing between the _Heikhal_ and the _Azarah_ where most male Jews would be standing.
Comment: @TamirEvan I linked the source, and see the ensuing discussion in the gemara to answer your question - the cherubs referred to were those sewn on curtains all around the Temple.

Framing a Page from a Holy Book