How to denote a simple slope coefficient (interaction)?

Question: I'm using sslope in stata to test the linear relationship between x and y for different values of my moderator. The output of sslope provides me with a significance level and a coefficient. As far as I know, a simple slope coefficient represents the slope of a regression line for a specific value of my moderator. I report standardized coefficients (betas, "b") in my regular regression table. However, I'm not sure how to report the coefficient provided by sslope. Should i denote this coefficient also "b"?
Comment: What do you mean by "standardized coefficient"?
Comment: You are mixing a lot of notation: simple slope coefficient / interaction / standardized coefficient. Which is it?
Comment: betas as provided by the "beta" option in regression in stata.
Comment: Indeed, I am confused. As far as I know, a simple slope is the slope of a regression line for a specific value of the moderator. The module "sslope" in stata provided me with this slope. My question is, how do I denote this slope/coefficient?
Comment: Can you post your output? Are you just interested in how to write this up in a scientific paper?
Answer: I don't know what sslope is but it reminds me of linear regression, where we build a model $Y=\beta_0 + \beta_1 x + \epsilon$ where:

$\beta_0$ is a constant.
$\beta_1$ represents the slope of the line that best fits the data.
$\epsilon$ is random noise

If this is the case, I would go for $\beta_1$ as the symbol for that coefficient. It there is no intercept (at $X=0$ we have $Y=0$ too) I would go for just $\beta$


Check box into value box

Question: Can this form builder allow me to have 3 check boxes, each check box (once checked) needs to have a corresponding value of £50 in a box 4. So if I check all 3 boxes then £150 will be shown in box 4?
Answer: I'm a developer with Cognito Forms.
You can add values to Choice field items, but you cant set the values to add up into the 4th option in the Choice field. You can set up a Calculation field to add up the values outside of the Choice field.
You can also select to not show the price values in the Choice field if you would rather the end user not see them.
In the following screenshots you will see what the Choice field settings look like. Followed by what the Choice field looks like with the Calculation field set up under it, targeting the Choice field. The last image is what this looks like when active on the form for the end user.

Check box into value box


Green Theorem in 3 dimensions, calculating the volume with a vector integral identity

Question: Let $E$ be a region in $\mathbb{R}^2$ with a smooth and non self-intersecting boundary $\partial E$ oriented in the counterclockwise direction, then from green theorem, we know that $$Area(E)=\frac{1}{2}\int_{\partial E} x\ dy-y\ dx$$
What is the analogue for Green theorem for volume of $E$ in 3 dimension? Also, a proof will be  nice?
Comment: an application of the divergence theorem (Gauss-Ostrogradsky)
Comment: example found here at MSE: http://math.stackexchange.com/questions/797915/use-the-divergent-theorem-to-verify-the-volume-of-a-circular-cone
Answer: The analogue becomes almost obvious if you think of $\frac{1}{2}\int_{\partial E} x\ dy-y\ dx$ not as the line integral of $\frac12 (-y,x)$ along the boundary, but rather as the flux of $\frac12(x,y)$ across the boundary. Which is what it is, since $(dy,-dx)$ represents the exterior normal. The significance of $\frac12(x,y)$ is that it's a field with divergence equal to $1$, hence the integral of divergence over a region is equal to its area.
In any number $n$ dimensions, the same thing holds (by the divergence theorem): the volume is equal to the flux of any field with constant divergence $1$ across the boundary. A nice symmetric field to use is
$\frac1n (x_1,\dots,x_n)$, which is $\frac13(x,y,z)$ in three dimensions. As janmarqz pointed out, this question has an example of this field used.  But any other field $v(x) =Ax$ where $A$ is a matrix of trace $1$ would work too.


are elementary symmetric polynomials concave on probability distributions?

Question: Let $S_{n,k}=\sum_{S\subset[n],|S|=k}\prod_{i\in S} x_i$ be the elementary symmetric polynomial of degree $k$ on $n$ variables.  Consider this polynomial as a function, in particular a function on probability distributions on $n$ items. It is not hard to see that this function is maximized at the uniform distribution.  I am wondering if there is a "convexity"-based approach to show this.  Specifically, is $S_{n,k}$ concave on probability distributions on $n$ items?
Comment: Specifically, if it is concave on probability distributions, then applying this to a uniform convex combination of a probability distribution and its rotations would yield the above maximization at the uniform distributions.
Answer: (I know this question is ancient, but I happened to run into it while looking for something else.)
While I am not sure if $S_{n,k}$ is concave on the probability simplex, you can prove the result you want and many other similar useful things using Schur concavity. A sketch follows.
A vector $y\in \mathbb{R}_+^n$ majorizes $x \in \mathbb{R}_+^n$ if the following inequalities are satisfied:
$$
\sum_{j=1}^i{x_{(j)}} \leq \sum_{j=1}^i{y_{(j)}}
$$
for all $i$, and $\sum_{i=1}^n x_i = \sum_{i=1}^n y_i$. Here $x_{(j)}$ is the $j$-th largest coordinate of $x$ and similarly for $y$. Let's write this $x \prec y$. For intuition it's useful to know that $x \prec y$ if and only if $x$ is in the convex hull of vectors you get by permuting the coordinates of $y$.
A function is Schur-concave if $x \prec y \implies f(x) \geq f(y)$. A simple sufficient condition for Schur concavity is that $\partial f(x)/\partial x_i \ge \partial f(x)/\partial x_j$ whenever $x_i \le x_j$. It is easy to verify that $S_{n,k}$ satisfies this condition for any $n$,$k$.
Notice that $x=(1/n, \ldots, 1/n)$ is majorized by every vector $y$ in the probability simplex. You can see this for example by noticing that the sum of $i$ random coordinates of $y$ is $i/n$, so surely the sum of the $i$ largest coordinates is at least as much. Equivalently, $x$ is the average of all permutations of $y$. This observation, and the Schur concavity of $S_{n,k}$ imply $S_{n,k}(x) \ge S_{n,k}(y)$.
In fact, $S_{n,k}^{1/k}$ is concave on the positive orthant, and this implies what you want. This is itself a special case of much more powerful results about the concavity of mixed volumes. But the Schur concavity approach is elementary and pretty widely applicable.
Comment: Thanks Sasho. My hope was for a slick Jensen-type proof, as is done with maximizing Shannon entropy.  At some point since my original question, I did come across Schur-convexity (see "Majorization and the Birthday Inequality" by Clevenson and Watkins, http://www.jstor.org/stable/2691301 ). I guess this answer is probably this slickest I'll find (assuming that the proof about $S^{1/k}_{n,k}$ being concave you mention is less easy.)
Comment: I have seen two kinds of proofs that $S_{n,k}^{1/k}$ is concave. Some are elementary (i.e. use little to no heavy machinery) but are long and messy. On the other hand there is a slick proof by Khovanskii http://www.math.toronto.edu/askold/1984-Doklady-6-English.pdf of the Alexandrov-Fenchel inequalities for mixed discriminants (and even mixed hyperbolic forms) using hyperbolic polynomials.
Comment: To clarify my comment above: $S_{n,k}$ is a special case of a mixed discriminant, and Alexandrov-Fenchel is equivalent to a concavity property of mixed discriminants that implies the concavity of $S_{n,k}^{1/k}$. Alexandrov-Fenchel for hyperbolic forms is vastly more general than concavity of $S_{n,k}$, but Khovanskii's proof is the only one I have seen that doesn't involve long tedious calculations. Here is one of the elementary proofs I have found: http://cms.math.ca/cjm/a144993. BTW, cute article about the birthday paradox!
Comment: Thanks! I'll take a look. (Indeed, the birthday paradox was what got into this.)


How do I monitor file modifications of a Linux user from the user process instead of the file-system itself?

Question: We have a requirement to fill that will give us a daily report on all the changes that were made (and who made them) through the SSH protocol; whether it be files or database resources.
Monitoring database actions are no problem with the exception that we have about 4000 queries per second and logging each just to capture queries from a certain user or host requires some planning. But it can be done so I'm okay with this.
We have a few senior developers who have ssh access to production web servers for various reasons. Files can be edited using VIM or other common text-editors such as Pico but a deployment system is suppose to be used instead. We need to watch and report on when the web environment is modified outside of this deployment process.
Our web directory structure is filled with over 5,000,000 different files and folders, some directories have so many files in it, the command "ls" breaks or simply hangs. This is a inherited CRM system but its live production. For this reason, utilities such as ossec hids, inotify or other system/file monitoring processes would require to much resources for real-time monitoring and notification.
Instead of monitoring the file-system, it should be possible to simply monitor the user and watch for when they access files or directories within a defined path as well as record the changes they make.
As for the requirements, we need to present a daily report of all file and database changes made throughout the day (via ssh), and if needed, produce what changes were made (a before & after).
The Linux command utility 'script' almost gives us the replay except it doesn't like to work when the user opens certain programs (vim, etc). Another method of recording is needed.
I'm surprised there isn't a bonafide package out there that has an all-in-one real-time terminal-based user monitoring solution; complete with directory path tracking, resource access, modifications with time sliders, event history that can be filtered by host or user (local/ldap/etc).
Or... is there one?
Comment: fswatch could be an option
Answer: I think auditd might be what you're looking for. Though I'm not sure if is capable of logging diffs.


iScroll 4 and highcharts compatibility issue

Question: i'm trying to use the highcharts library with iScroll4. You can see a complete example here.
The problem as you can see is that the outer div's width is getting ignored by the browser and the iScroll div apparently doesn't show at all.
What i want to achieve is having a graph with width=1000px inside a container with width=200px. Of course i want the graph to be scrollable (horizontally) so that i can see all the graph and not only the left part. To do this, i want to use iScroll4 as i already used it inside the same project for another feature.
Can you point out where the problem is in my code?
Thanks a lot!
Answer: I think this could help you.
http://jsfiddle.net/pn5SW/5/
you have to set overflow-x: for div. try to scroll using the space below  #charts div (portrait mode).
Highcharts to use touch events of the ios, they prevent the default events, you may try this alternative solution like this. http://jsfiddle.net/HXUmK/126/
Comment: This is not what i want. I want to scroll the chart itself. Btw, thanks for trying


Fantasy book examples in PhD Thesis

Question: I have a question regarding the use of fantasy books in a PhD thesis. Imagine for example that I'm writing an example motivating the use of databases. Can I design e.g. a database composed of Game of Thrones characters and put it into the thesis? I noticed that some people put some fake examples or examples from Greek mythology so I'm wandering if it is legal to put examples from different books.
Comment: Ask your advisor first, it could be they find it cool or childish.
Answer: I agree with Wrzlprmft that, assuming the names are trademarked, mere use of the names as hypothetical entries in a database would not constitute trademark infringement.
And names cannot be copyrighted.  See Circular 33, US Copyright Office, "Works not protected by copyright" which states on p. 3 that "The name of a character" cannot be copyrighted. Online at https://www.copyright.gov/circs/circ33.pdf
But suppose that somehow, somehow the GoT people found your thesis and sued. Your thesis would instantly become internationally known. You can't buy publicity like that. ;-)
Answer: This isn't a definitive answer, as I'm not a lawyer. And laws differ over the Globe. But such things are a matter of civil, not criminal, law, generally, so the question comes down to whether a "rights holder" would object and file suit. This is more likely in some cases than others and, if a suit is filed, it is very expensive to defend.
But, just a guess here, that if the characters you wish to use are covered by Trade Mark that you would be on shakier ground than otherwise. I, personally, would avoid the use of Disney characters, for example, as I think they are all trademarked and the trademark holders can be very sensitive about repurposing those characters.
Once those rights expire, however, they are fair game, and the only questions would be about whether this adds to or subtracts from the paper you want to write.
Presumably you are associated with a university. Many of them have an office of intellectual property rights that can give you actual legal advice on your question. I haven't looked at the trademark question for GoT characters, but would guess that they might well be covered. Such "properties" can be very valuable and the rights holders want total control. They also have a legal team that might overreact.
Comment: Trademarks are protecting the trademark holders' brand and more generally commercial exploitation of their intellectual property. Nobody is buying a PhD thesis because it uses characters from Game of Thrones as examples and the PhD thesis is not sold using the inclusion of GoT characters for marketing. So, we are very far from any potential trademark infringement.
Comment: A few useful links on [fair use](https://en.wikipedia.org/wiki/Fair_use) and [trademark protections](https://law.stackexchange.com/a/39073/24374). My reading of these is that including these names (just the names) in a PhD thesis should be fine...but even if my reading is correct (always dubious), one must ask if asserting these rights is worth the potential legal fallout. Plenty of great names in Greek mythology....
Comment: @Buffy: *"Affecting commercial value" is a copyright issue, generally, not a trademark issue.* – Well, copyright is clearly not affected either. For that you would have to include entire text passages, pictures or similar. — *And being civil law, you can still get sued by aggressive legal teams.* – Well, you can be sued for a lot of things, more crucial is what you can be convicted for.
Comment: I used to use a very recognizable picture of a very famous mouse with the heading, "Is this mouse fair use?"  I got a lot of interesting discussion and never got The Letter from [BakerHostetler](https://www.bakerlaw.com/IntellectualProperty).  Of course, my example was never in a public repository, either.
Comment: @BobBrown, hmmm, do they send letters or just arrive at your door guns a' blazing?
Comment: @BobBrown Ref: Yosemite Sam (TM).
Comment: "Is this gunslinger fair use?"  I've never been on the receiving end, for which I am grateful, but I understand that the first step is a 'cease and desist' letter, possibly with a demand for payment for prior use.  Blazing guns and courtrooms are *expensive!* Fun fact: the Baker of BakerHostetler was Newton D. Baker, Secretary of War during WW I.  I know this because I went to Newton D. Baker High School.
Comment: @Wrzlprmft, perhaps, but don't be too sure. "Affecting commercial value" is a copyright issue, generally, not a trademark issue. And being civil law, you can still get sued by aggressive legal teams.
Comment: @Wrzlprmft, of course it would be unlikely that the TM holder would ever learn of the usage.
Answer: I am not a lawyer, but I doubt a court would consider your proposed use a violation of either trademark or copyright:

Individual names are generally not able to be protected by copyright.
HBO has trademarked a whole bunch of GoT-related things including character names, but simply referencing a trademarked name is not a violation. In essence, trademark law boils down to "are you trading off somebody else's reputation/brand?"

As a point of data, Alison Green's advice column "Ask A Manager" frequently uses GoT character names to conceal the identities of letter-writers and their colleagues when describing workplace dilemmas.
AAM is a fairly well-known column, successful enough to have a compilation book published. It's more visible than most PhD theses will ever be, and as far as I can tell the use of GoT names has never been an issue. If it flies there—which apparently it does—it's unlikely that doing something similar in your PhD thesis is going to cause problems.

Fantasy book examples in PhD Thesis


Why do none of the sorcerers in Dr. Strange have a ranged attack?

Question: They said they could conjure weapons, but all of them chose some sword or whips. No guns or arrows?
Comment: Could you expand on this please? Why do you think they should have guns or arrows?
Comment: @Mooz Like in the army they have spearmen and archers (they are an army against the dark dimension, right?). They look stuck in the medieval world (except the wifi joke). And some arrows would be practical. Otherwise, some mundane martial artists would be more effective (normal people know how to use gun and stuff).
Comment: This also begs the question of why magical *sorcerers* choose to do battle in such a traditionally *physical* sense. Surely magic is not so mundane?
Answer: As to the general lack of ranged weapons being used in the film, this probably relates to the style of martial arts used (named Kamar-Taj after the temple) which largely seems to be based on melee-style weaponry.

Since Kaecilius' henchmen were all former acolytes of the Sorceror Supreme, it stands to reason that the protagonists and antagonists would all fight in much the same way, using much the same weapons.

That all being said, on several occasions we see Kaecilius (and his henchmen) creating spears which they then throw at Strange.
Comment: Which then begs the question "Why were all of the sorcerors using a martial arts style that emphasized hand-to-hand melee?" My best (out of universe) guess is that for dramatic purposes the directors didn't want two wizards blasting away at each other with fireballs from 50 yards apart.
Comment: @RobertF - Well, presumably a desire to avoid it looking too much like Harry Potter :-)


Open source threaded forum software that does not require user registration

Question: Is there any open source forum software that supports threading and does not require users to register for an account before posting? This is somewhat similar to anonymous imageboards, but with threading, no images, and optional user registration.
Answer: Probably most forum software have such an option, you just need to set it correctly.

phpBB can do that. You just need to set (in Forum Permissions) Standard Access for the Guest Group.
NodeBB is a more modern option. See the posting without registration in the Testing Ground forum on their demo site https://try.nodebb.org/


Cutting machine with Linux: fsck died with status code 4

Question: We have a cutting machine which is working with Linux.
I don't know a lot about Linux, so I attach a photo of the error which we get.
I will be happy if someone can help.
Comment: ...also if that machine needs to be calibrated, and that calibration data is on disk, and its corrupted... there may be a risk of causing damage to the machine itself. there is a whole bunch of usb sticks in the picture, hopefully that means it reads production data off usb, and you have backups of those at least... I'm wildly guessing so I'll shut up now. All the best.
Comment: The drive (sda) is dying and needs to be replaced. Don't run `fsck` anymore. Ask your IT if you have backups / spares for this drive. If not, you'll have to try your luck with `ddrescue`, or ask the manufacturer of this machine. Usually the firmware for such machines is proprietary so you can't just download a new one and make your own from scratch...
Comment: Most likely the people saying the hard disk in the machine is dying are correct. However, if it's in a machine shop, or otherwise subject to vibration, it's conceivable that something has vibrated loose, and is making poor electrical contact. You might try shutting it off, opening up the case, and reseating (unplug and firmly replug) the power and data connectors to the hard drive (on both ends.) (If you're not familiar enough to be comfortable doing this yourself, definitely don't wing it, find someone who is.)
Comment: Ultimately, we're still a bunch of unknown people from the Internet, and while the information we give (at least, that's true for high-rep users) is in good faith and at the best of our knowledge, we don't know enough about your workplace setup and environment to give an exact answer. So the best way of proceeding for you might be not to touch anything and escalate to the person responsible for the machine.
Comment: @GlennWillen This sort of an error (unrecoverable read error) is reported directly by the drive, it's certainly not a communication issue (those look somewhat similar but the "Additional sense" message is different).
Comment: who did assemble the machine? who did sell the machine to you? Now it is time to spend money on fixing the issue, instead of doing trial&error with "internet answers".
Answer: These errors on your picture are coming from the kernel and they indicate the kernel has not been able to read a data block (sector), and the attempts to reallocate it have failed (this is a standard feature of HDD drives):
 Descriptor sense data with sense descriptors (in hex):
         72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00
         00 40 08 a0
 sd 0:0:0:0: [sda]  Add. Sense: Unrecovered read error - auto reallocate failed
 sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 40 08 a0 00 00 08 00
 end_request: I/O error, dev sda, sector 4196512
 ata1: EH complete

This strongly suggests that your storage is dying/dead, thus e2fsck cannot complete the task.
If you really care about data, send the HDD to any company doing data restoration and ask them to image it. You could try to image it yourself (by using ddrescue) but it's not safe and may lead to data loss.

If you have backups and you need a quick fix, you can attempt to fix bad blocks yourself: https://www.smartmontools.org/wiki/BadBlockHowto
Comment: To the question author, in case you are not used to dealing with Unix experts, I would add that 'catastrophic' has its own particular usage in this field, and that you should not fear war, famine, or a plague of pestilence descending on your workshop . Worst case, you will make the actual repair by an IT professional more expensive.
Comment: Note that it's not the `fsck` status code that says that it's dying, it's the error messages before that.  Those are strongly indicative of a hardware fault.
Comment: @HughW Worst case, you will make the actual repair _impossible_ (data loss). In this situation, there's unlikely to be irrecoverable data, but in general, you _can_ break things hard enough that the entire world couldn't help you.
Comment: Very true, although I will say I'm a bit skeptical that "**not** safe and may lead to data loss" is an appropriate representation of the risks involved. To be fair, I'm not an expert in data recovery so I don't know how the risks should really be characterized, but I do understand certain basic things about Linux system design and hardware and I can use `ddrescue` just fine. I know other people with similar backgrounds who have also done it. Are you really saying people like me aren't qualified to use this tool?
Answer: The command fsck is used to check/fix the integrity of a filesystem. The command exiting with code 4 means that there are errors on the disk that fsck did not correct.
In short, it means the machine's hard disk (or storage) is damaged, perhaps physically. The best thing would be to contact the maintenance service of the cutting machine, or anyone that is responsible for such machine.
Note: one could try the command
fsck -yv /dev/sda

which forces a repair of the disk, while printing a verbose output. We don't know what your duties are so you'll have to see whether you want to try that, or leave the responsibility to someone above your pay grade.
Comment: Don't ever run fsck on a dying disk. Just get the data off
Comment: "Unrecovered read error" probably means the disk is physically dying, so this is probably a stopgap at best.


A complex manifold which is quasiprojective in two different ways

Question: Does there exist a complex manifold M which is a quasiprojective variety in two "essentially" different ways?  Let me be more specific.  I'm looking for a complex manifold M together with two projective varieties X and Y such that M is a locally closed Zariski dense subset of both X and Y.  This gives two different notions of "algebraic" objects on M, and I want them to be different.  For instance, can the resulting sheaves of regular function on M be different?  Or the Picard groups?  etc...
Comment: The key point is that this is not exactly a question about abstract algebraic geometry.  Rather, I am looking for (and, fact, found -- see Georges's comment below) a complex manifold M that can be "stiffened up" to be a quasiprojective variety in two different ways.  On a naked complex manifold, there is no notation of things being "algebraic", only holomorphic.  The example given by Georges says that knowing which things are "algebraic" is really new information that cannot be gleaned from the complex structure.
Comment: A fancier thing one could say is that the moduli space of algebraic structures on a complex manifold can contain more than one point.  I wonder how large it can be?
Comment: I'm afraid I don't understand the question. In abstract algebraic geometry, things like the sheaf of regular functions and the Picard group of a variety M are intrinsic, so they should not depend on the projective embedding of M. But one can have two independent ample line bundles, which give two projective embeddings. Is that what you mean: find M such that Pic(M) is large, and the ample cone is not just a ray?
Comment: I forgot to mention one thing which should be kept in mind.  Serre's GAGA paper says that if M is a COMPACT complex manifold, then M can be given an algebraic structure in at most one way.  Thus the M that Georges supplied was by necessity noncompact.
Answer: Dear Andy,
consider the punctured complex line C* and let M=C* x C*, seen as a holomorphic manifold.
You can embed M into P^1 X P^1 and get the standard algebraic affine structure on M, call it A.
On the other hand hand given an elliptic curve E there exists a P^1-bundle X over E such that, if you delete a section of this bundle X -->E, you get a Zariski open subset U of X which is algebraic, NOT AFFINE, but nevertheless biholomorphically isomorphic to M.
The Picard group of this U is isomorphic to that of E and so definitely not isomorphic to that of the affine variety A.
This construction is due to Serre and is mentioned in Hartshorne's "Algebraic Geometry" (Appendix B, Example 2.0.1, page  440).
Yours friendly,
Georges
Answer: This may be relevant, although I'm not sure if it answers your question directly. The Russell cubic x+x^2y+t^2+z^3=0 is diffeomorphic to affine space A^3. But, it is known not to be algebraically isomorphic to A^3. I'm afraid I don't know the references for this.


How was King Shantanu able to give Bhishma boon of icchamrityu(death at self will) when he was neither God nor Sage?

Question: Iccha mrityu sounds like a very heavy vardaan but Shantanu was able to give it despite being a mere mortal King. He was neither a sage with high ascetic merit nor a Deva or part of trinity. Various other people had to do heavy penace to get such boons but Shantanu gave it just like that too Bhishma. Even Jaydath was not given such a boon by Lord Shiva.
Comment: This is a duplicate question. Please see the answers here. https://hinduism.stackexchange.com/a/14451/24460
Answer: According to Srimad Devi Bhagwatam.:

29. Vyāsa said :-- The part incarnations of Suras and Asuras on this earth, and their names I am now saying to you in brief; hear.:
35. Śantanu was the part incarnate of the Ocean; his wife, of the river Ganges in human form.
(Srimad Devi Bhagwatam 4:22:29&35).

Again,

At that time Bhagavān Hari told them one by one :--
45-67. ... O Gange! You will also have to take incarnation in Bhārata as a river, purifying all the worlds, to destroy the sins of the inhabitants of Bhārata. Bhagiratha will take you there after much entreating and worshipping you; and you will be famous by the name Bhagirathī, the most sanctifying river in the world. There, the Ocean born of my parts, and the King Śāntanu also born of my parts will be your husbands. . . (Srimad Devi Bhagwatam 9:6:45-67).

But, as we saw in earlier verse Sāntuna = Ocean (Samudra).
As, for Bhishma he got his boon because of his love, devotion and sacrifice towards his father, while jayadrat didn't got it because his penance was solely based on his hatred towards Pandavas to take revenge from them for his insult done by them. So, Karma matters. And parents have the power to protect their child. Plus, Bhagawan Shiva knows the outcome and so he gave boon to Amba for Bhisma's death and as told by Lord Krishna in (b.g. 11.34) to Arjuna that jayadrath, bhishma drona, karna, etc. are already dead.
Last, but not the least.:

"sá mahimā́ sádrur bhūtvā́ntaṃ pr̥thivyā́ agachat samudrò 'bhavat |" (Atharva Veda XV:7:1)
He [Vratya (Bhagawan Shiva)], having become moving majesty, went to the ends of the earth. He became the Ocean".

I hope this clarifies all your queries.
Comment: Thanks a lot!!!
Comment: Welcome. ..


Uses for PLA scraps

Question: I recently got a 3D printer and have been experimenting with it a lot, resulting in a lot of failed prints (as well as successes, fortunately).
I'd like to, if possible, find a way to reuse the material from these failed prints.  I am thinking about two methods:

The obvious thing to do with the material is to chuck it in an old toaster oven and reuse it for injection molding.  Is this something that is reasonably easy to do? If so, what temperature would be reasonable to use? What materials would be good to use for the mold? (off the top of my head, silicone or printed ABS with some kind of sealant seem the most promising)
Are there other ways to easily reuse the material? I've noticed that when PLA is heated to somewhere around 50-60 degrees C (120-150 F) it becomes somewhat soft and malleable. Does anyone have experience molding hot PLA?

EDIT:
To be clear, I'm specifically asking about ways to reuse scrap PLA material, not just leftover filament, and not ways to turn it back into filament or to just recycle it. I'm particularly interested in the viability of the two methods I suggested, and if anyone has experience (positive or negative) with either I'd like to hear about it.
Comment: Possible duplicate of [How to recycle filament material from printed parts?](https://3dprinting.stackexchange.com/questions/59/how-to-recycle-filament-material-from-printed-parts)
Comment: Possible duplicate: [How to recycle filament material from printed parts?](https://3dprinting.stackexchange.com/questions/59/how-to-recycle-filament-material-from-printed-parts) and [What to do with failed/unwanted 3D prints?](https://3dprinting.stackexchange.com/questions/1266/what-to-do-with-failed-unwanted-3d-prints).
Comment: Not a duplicate, though I might not have been getting it across well. My question is specifically about personal _reuse_, not recycling. Edited to try and add clarity.
Answer: Here is a great article on the subject, How to make your own filament by recycling old 3D prints | Part 1.
At $20/kg for new material, it is going to be hard for recycling to break even; but, if the cost is not your concern, there are some options.
Here is another creative option that I just saw... Cue amazing electric guitar riff:

Guitar Picks (and jewelry)

Here is the video: Failed Print Recycling Revisited // Guitar Picks, Earrings, and More.
Comment: I thought I covered both options - making filament and reusing scraps (be they filaments or parts scraps) by melting them into flat plates and them cutting them into jewelry or guitar picks.  IMHO, re-using PLA (unless you are talking LARGE quantities) will always require time and money (it will never be free).  Whatever solution will require a lot of passion regarding not throwing the scraps in the trash to justify the time and cost to re-use your PLA scraps.
Comment: A nice answer, but doesn't quite address what I'm looking for. I don't want to turn the waste PLA back into filament, I'm looking for other ways to reuse it. Thank you for the interesting links regardless!
Comment: That's part of what I wanted to address with my particular suggestions. While flat jewelry and guitar picks are easy to 3D print or make by other means, injection molding and hand sculpting can make things that are difficult or impossible to 3D print. I admit to not paying enough attention to the guitar picks link- it goes into more detail than I realized!
Answer: I ended up buying a little handheld 3D pen. It comes in handy when printing models that require assembly. You can use the leftover filament in the 3D pen. If you don't have a 3D pen, you can use a soldering iron (as long as you can control the temp) to weld items together. I works well for part repairs and assembly.
The 3D pens is also handy for quick simple prints, as mentioned above. A guitar pick is a good idea and very easy to make with the 3D pen.
As for making your own filament, there are a couple of machines I would recommend looking into.
First you will need something to prep the material.  This shredder will help.
To make your own filament, here are a couple of options

DIY
Off the shelf

Regarding Injection Molding, I have never done it, however found some good info on molding PLA.
Comment: Your right, Sorry P. I updated my response for you.
Comment: A nice suggestion! Doesn't quite get at the heart of what I meant to ask, but a very good idea nonetheless. Regarding the soldering iron idea, what temperature would you recommend using? I do not have a decent soldering iron at the moment, but am in the market for one and this would be a good secondary use for it.
Comment: Thank you very much for the updated response! The links were very interesting, and the last one in particular (while obviously more specialized than I may be able to use) is exactly the kind of thing I'd been trying and failing to find before asking this question. My Google-Fu is weak, I'm afraid...
Comment: hey P, I created a video here on getting the most out of Google. That should help you search Google a bit more.https://www.youtube.com/watch?v=Y1_ZbsMavE8&list=PL8BBKsD2COHs-qlBFK3w07zHs2oAav7AM
Answer: https://preciousplastic.com/ Is a fantastic project that promotes plastic recycling into useful objects. They offer free blueprints, videos on how to build the recycling equipment, and offer suggestions on what to make of your recycled goods.
Personally, I am looking into making garden bricks or paver stones. I have not found the ideal temperatures or heating methods just yet.

Uses for PLA scraps


Oil light is always on (2006 golf 1,4i)

Question: The oil light is always on in my 2006 VW Golf 1.4i. I have tried changing the oil pump, oil switch, and even putting more oil in, but the light remains on.
Comment: Is this a 'service now' light or low oil light?
Comment: How many km or miles on the engine?
Answer: There are only a few possibilities:

Oil pressure is actually low.
The light is overloaded with meanings and it is trying to tell you something else.
There is a faulty component.
There is a fault in the circuit.

The first thing to do is to make sure you understand what the light is trying to tell you. For example is the light solely a pressure monitor or could it also be a service reminder as well. The owners manual will tell you this.
Next see if you can find a schematic of the light circuit. It will be in the Bentley manual for the car if no place else. That will give you the definitive answer about what causes the light to come on.
Armed with that knowledge, verify that things are working as you think they should. For example, does the oil pressure switch actually seem to work (pull the connector off and hook a meter to it and see if it changes state when you start the engine).  You could also pull the pressure sensor and connect a gauge to see what the pressure actually is.
Once you have come this far the only remaining possibility is a short in the wiring.  Assuming the oil pressure was good. If the engine has enough time in it if is possible that the bearings are worn enough that the pressure is actually low. A really dirty oil filter might also cause low oil pressure.
Comment: If it's a service light, it may just need to be reset. Usually the dealer will charge you to do so, but there is a special super secret procedure to do it yourself.
Answer: Definitely should get the cars fault code memories read. Ill bet this will provide you an actual informational message about the meaning. It could just be a faulty oil level sensor, but its guesswork unless you know what the car is actually telling you.
These cars use a databus and pass binary messages between electronic control units so getting wiring diagrams wont help.
You could try owners forums in your area and post a request for someone to do a VCDS scan for you.. Or failing that pay the dealer to do so.

Oil light is always on (2006 golf 1,4i)


Is using a robotic operating system still considered bare-metal C?

Question: I want to get experience with low-level, bare-metal programming and am not sure if a project that uses an ROS counts as that.
Comment: research Forth programming language
Answer: Bare metal programming is defined by not using any abstractions that might be provided by an OS and working directly with the hardware. Wikipedia Technopedia.
ROS provides an even higher level framework which builds on top of your computer OS, such as Linux, or Windows.
You can learn a lot about low level concepts while using frameworks such as ROS. And you likely will find that you may want to select a specific part of a larger system to implement at the lowest level. A good learning project could be to reimplement an existing piece of functionality in bare metal instead of trying to recreate the entire system at the lowest level.
Comment: So, if I am understanding correctly, using an ROS is not bare metal programming because you need to be using a computer OS to use it?
Comment: Yes, that is correct.
Answer: I second @Tully's statement that Bare Metal is defined as "without the OS in ROS".
Should you use an OS depends on the size of the processor. An 8 bit μC? Bare metal C. The ROM space is so little that you don't need the abstractions of C++ let alone that of an OS.
An ARM? Linux takes up only 3MB RAM to run.
An even more capable platform? An OS won't suffice, a plethora of third-party user-space utilities will also be needed as to utilize the platform's capacity.


What is a TMF in topology?

Question: What is a topological modular form? How are they related to 'normal' (number-theoretic) modular forms?
Comment: It really would be an injustice to mark just one answer as the accepted one...
Answer: If you know about classical modular forms, and you want to understand what they have to do with tmf, it is good to contemplate something more classical: the "derived functors of modular forms".
Modular forms of weight $n$ are $H^0(M, \omega^n)$, where $\omega$ is a certain line bundle over $M=$compactified moduli stack of elliptic curves.  There is non-trivial cohomology in
$H^s(M,\omega^n)$
for $s>0$.  This comes in two flavors:
* free abelian group summands in $H^1(M,\omega^n)$ for $n\leq-10$.  These correspond by a kind of "Serre duality" to the usual modular forms in $H^0(M,\omega^{-n-10})$.
* finite abelian groups (killed by multiplication by $24$) in $H^s(M,\omega^n)$ for arbitrarily large $s$.
There is a spectral sequence
$H^s(M,\omega^{t/2}) \Rightarrow \pi_{t-s} Tmf$,
and the edge of the spectral sequence gives a map $\pi_{2n}Tmf \rightarrow H^0(M,\omega^n)$.  This is essentially the map Chris describes in his answer.
Slightly confusingly, the gadget I've called Tmf (which is the global sections of a sheaf of spectra over $M$) is not the same as TMF (the $576$-periodic guy, which is sections on $M'=$stack of smooth elliptic curves), or tmf (the connective cover of Tmf, which I don't believe is known to be sections on anything).
I recommend Goerss's Bourbaki talk for learning more about this, especially section 4.6.
Comment: @Andre Henriques: The text describing your edit says you added a link, but the only link I see is Charles's Bourbaki link. I assume you meant to link the text "alt text."
Answer: There is a Wikipedia entry on topological modular forms, where you can see further references. The primitive version of Topological modular forms is as a generalized cohomology theory. Like K-theory and Cobordism theory it is a functor from spaces to graded rings, which satisfies the Eilenberg-Steenrod axioms, except for the dimension axiom.
In the case of TMF the ground ring is complicated, but essentially known. It is periodic, like K-theory, with period $24^2= 576$. There is a map of graded rings:
$TMF(pt) \rightarrow MF$
where $MF$ is the graded ring of integral modular forms (with appropriate grading based on the weight of the modular form). This map is NOT an isomorphism. It is neither surjective nor injective, but the kernel and cokernel are both torsion. In fact this torsion is only at the primes 2 and 3.
The more sophisticated version, and the one which makes makes the connection to modular forms more clear, is to view TMF as an $E_\infty$ ring spectrum. The category of spectra is similar to the category of topological spaces, except the suspension functor is invertible. The things which represent cohomology theories live in spectra, and TMF is a ring object in spectra.
The connection to modular forms arises when you try to extend many constructions from algebraic geometry to this larger world of spectra. It is impossible to do the subject justice in a single post, but roughly you can look at the analog of elliptic curves over spectra. These have a moduli stack and the ``ring'' (i.e. ring spectrum) of functions on this stack is TMF.
Comment: The question is http://mathoverflow.net/questions/308/elliptic-curve-over-spectra
Comment: @Chris: You can edit your answers, ya know. :-)
Comment: Wow, that's amazing. I don't know what would be the right way to proceed. It's probably easiest if I make a separate question about analogues of elliptic curves over spectra, sorry to ask so much!
Comment: btw: That "242" should be a "24 squared".
Answer: You can think of a topological modular form as a point on the tmf spectrum, but it's not clear that this is a useful view, unless you expand your notion of "point" to a large class of objects.  The relation to modular forms doesn't need to go through the machinery of spectra: tmf is a multiplicative cohomology theory, so if you evaluate it at a point (or anything else), you get a commutative ring.  There is a natural homomorphism from tmf(point) to the ring of modular forms with integer coefficients (taking tmf^n(point) to holomorphic level 1 forms of weight n/2), but it is neither injective nor surjective.  If you invert 6 in the source and target, the map becomes an isomorphism.
Comment: I should mention that there is a difference between TMF (the 576-periodic spectrum) and tmf (the connective cover).  TMF(point) maps to modular forms with possibly negative weight, that may have poles at the cusp, while tmf(point) maps to traditional modular forms.
Comment: Wait, wait, ok. What's so good in the definition of the tmf that makes it so similar to integral modular forms?

What is a TMF in topology?


Is there a way to integrate other software in a Blender pipeline?

Question: I'm considering starting a small studio, but the people I know do not use Blender.  Is there any known way to effectively integrate other programs into a pipeline like Maya and After Effects with Blender?  I watched Francesco Siddi's talk on Blender Pipeline, but admittedly, I found it difficult to understand.
Comment: I don't know that there is a single step by step approach, but the way I go about integrating tools into a work flow is to try to answer two questions: What order makes the most sense for using the programs?  (obvious example: Lightroom should go before Photoshop) What has to be done in each program to optimize moving work between them? (what format they both understand , for example.)
Comment: I think this question is likely to be flagged as opinion. Can you provide a more concrete (aka answerable) example?
Comment: I'm just wondering if there is a step by step approach that studios use with predominantly Blender to integrate other programs in their pipeline.  Or, is Blender pipeline only meant to be used with Blender?
Comment: Yes those the questions I have for sure. Because for example, if I am working with a concept artist, it's pretty easy to import the vector or image in Blender, model it and get it textured in Substance Painter or Maya. But if I have the model made in Blender with compositing and texturing, would it work to export that to Houdini for physics? Or if you are working with many environments and objects in many different programs, how can you use it all in Blender to preview when the environment and poly count is huge?
Answer: I used to be the supervisor of a studio where we are using Blender.
First, I implanted blender for modeling/UV, you can then export the mesh in obj or FBX and used them in any CG software (Maya, Max, etc ...)
Then we started to animate in Blender and render in 3DS Max with Vray, so all Modeling, Setup, Animation were done in Blender, then you export the all scene in Alembic, that keep animation data and you can load it in Max or Maya to make the render.
As for Compositing software, of course you can use any Blender render (use pass render in EXR) in Nuke, Fusion or After Effect.
So yes, Blender can be implented, in my humble opinion, in any pipe, and more easely if you are starting your own bussiness.
Hope it helps you
Comment: Wow thanks that excellent to know that it can work! So from what I gather Blender files, compositing and animation data can be seamlessly integrated into other programs? But can other programs export to Blender as well?
Comment: Any programs that can export to blender-readable file types work. Like .obj, .fbx, alembic files, and any image files. So, in other words, it depends on the program and what you're using it for. But most likely, yes


clone partition at same offset?

Question: Maybe i do not need it to be at the same offset but...
I have 2 PCs. I deleted all the partitions on one of them and realize the first partition is to restore the os VERY quickly. I had the partition on the other PC. How do i copy the partition and copy it to the same location so the firmware can launch it correctly and allow me to restore quickly.
Answer: You can use the command line dd utility from a bootable Linux live CD. It will make a block-level copy of one drive to the other.

clone partition at same offset?


Work done against a force

Question: Consider a body of $1\ \rm kg$ mass at rest at ground. Now as we know, it can be lifted by a force equal to its weight. So we have to apply a little bit more force then its weight. let $g= 10\ \rm ms^{-2}$, its weight is $10\ \rm N$. So I apply a force of $20\ \rm N$ or $10\ \rm N$ net force. As we know all the work I shall do will be converted to P.E of the mass. In case of friction my work done is wasted as heat.But what in the case if we consider a frictionless world for a while and there is no gravity now if we consider a mass moving with constant velocity in space with $10\ \rm N$ force applied on it and an opposing force of $-10\ \rm N$  acting on it where the work done by $10\ \rm N$ force against $-10\ \rm N$ will go?
Comment: It will go into the object, which supplies the 10 N. That pulling force must come from somewhere - maybe a rocket (so the energy is spent to burn and accelerate fuel) or a gravitational field (so the energy is spent "moving" the planet / stored as potential energy) or alike
Comment: Just to be clear, are you saying there are no forces (gravity, friction, etc.) acting on the mass except for 2 equal and opposite forces and the velocity is constant?
Comment: Of curse! I an talking about the same thing
Comment: Please, separate your question in paragraphs, and use commas and full stops. If you make reading easy, you'll surely get better and more useful answers.  Try to state your question in a calm and organised way.
Answer: In the case of an object moving at a constant velocity with two equal but opposite forces acting on the object, the net work done on the object is $W=\int \vec F_{net} \cdot d\vec s= \int \left (\vec F_1-\vec F_2\right ) \cdot d\vec s=0$. One force inputs energy and the other removes energy.
Without knowing more about the forces in question we cannot say where the energy is coming from or going to. For example if we are dealing with two conservative forces then the potential energy from one force is being converted into potential energy of the other force. If we allow friction back into our world and one of the forces is non-conservative (like some dissipative force), then the energy will be lost to heat.
All we can say is that the object will not be changing its kinetic energy.
Comment: OP indicated that its a "frictionless world" so all forces are conservative.
Comment: @Artem Thanks. I have addressed this in my answer.
Answer: The formula for work is:

The work $W$ done by a constant force of magnitude $F$on a point that moves a displacement $s$ in a straight line in the direction of the force is the product $W = F \cdot s$.

When we are talking about the world without friction, and the body (point) is moving straight with constant velocity we can say in accordance with the Newton's first law that:

In an inertial frame of reference, an object either remains at rest or
  continues to move at a constant velocity, unless acted upon by a
  force.

In your case where two equal forces $\vec{F_1} = -\vec{F_2}$ act on a point in opposite directions, in accordance with the superposition principle:
$\vec{F_1} +\vec{F_2} = 0$.
Then based on $\vec{F} = m\vec{a}$, follows $\vec{a} = 0$ and velocity is a constant, moreover by inertial frame introduction above we can set $s = 0$, in inertial frame, where point is at a rest.
If we talk about $F_1$, and we want to calculate the work $W_1$ done by $F_1$, using the formula above we get $W_1 = F_1 \cdot 0 = 0$.
Comment: Just because net force is $0$ does not mean displacement is $0$.
Comment: Corrected an answer about inertial frame
Comment: "if we consider a mass moving with constant velocity". The OP is considering a scenario where we are in an inertial frame and we observe the object moving at constant velocity with two equal but opposite forces acting on it. I can see what you are doing here now, but you should explicitly tell the OP in your answer why this new scenario you have created still answers the original question.
Answer: Good question!! And the answer is simple but interesting!
In your case, the work done by the two forces will be stored in that body. But the interesting thing is that: what will be the amount of work done by these two forces on the body?
Before we proceed, you must understand these five things:
(1) Work will be done by a force only when some kind of displacement is caused by it. If it doesn't cause any displacement, it doesn't do any work.
(2) The displacement caused can be outside eg.  displacement of the body from point A to B. Or it can be inside of the body eg. compression of the body by 1 mm.
(3) The work (or we can say energy) is generally stored in a body in three forms: Potential energy, Kinetic energy, and Internal energy.
(4) The PE and KE is measured with respect to the surrounding because height or speed is always with respect to surrounding. The internal energy is not measured with respect to the surrounding but with respect to it's initial phase/ energy level.
(5) Further, the internal energy can be stored by a body in two forms: (a) reversible or elastic or temporary eg. potential energy stored in a compressed spring. (b) irreversible or inelastic or permanent eg. slight heating of the spring due to continuous compression.
Now let's analyze your case. The two equal & opposite forces are being applied on the body from opposite sides. These two forces will try to compress the body. Now it depends on (1) the material of the body (2) the magnitude of the applied forces and (3) the duration for which the forces are being applied. These three things will decide that how much compression is caused in the body i.e. whether it will be in mm or micrometre or nanometre... and whether it will be elastic or inelastic... And all that energy will keep on getting stored inside that body.
This continuous force/pressure over very very long period of time can even cause metamorphic changes inside that body. For ex. formation of coal from wood, formation of metamorphic rocks, formation of stars and planets etc..
Hope, it clarifies your doubt!!

Work done against a force


Stream audio from youtube

Question: I just want to stream (whitout downloading) a youtube video.
Is there an easy way to do this with python or exists a script to do that?
Or i must download in a temporany file the video, convert it and play?
Comment: I imagine it would be tricky because Youtube is flash... however, there are some online services that let you convert the video into audio... have you thought about that? My favorite is keepvid.com
Answer: pafy is a Python library that can be used to retrieve URLs to pass to VLC or mplayer, etc. You can specify audio only. It's well documented here and can be installed with sudo apt-get install python-pafy.
Note it comes with a command line tool called ytdl which seems similar to youtube-dl and, as such, won't really do what you want. You'll have to write some python. I assume by the nature of your question this is no problem, but let me know if you need further help.
Comment: This is so cool, just one file which do what i want. Thank you! :)
Answer: This is not the perfect solution for your problem, but it will maybe help you.
youtube-dl
There is a command line tool called youtube-dl, which offers many options. I think it will first download the full video and then convert to audio. I'm not sure whether there is a possibility to only download an audio stream, but I guess not. Also, youtube-dl is written in python, but it's not only a simple script.
If you take a look at the manpage, look for the post-processing options. --extract-audio for example will convert the video file to an audio file. You can also set the --audio-format and the --audio-quality. You can also run any custom command after downloading with --exec CMD.

Get it from the Ubuntu Software Center: sudo apt install youtube-dl
Get it from Github: Then update it with sudo youtube-dl -U

VLC steaming
Alternatively, you can use VLC to stream the video and just ignore or turn off the video function.
It should work to copy the url, open vlc and press CTRL+V or open a network steam (CTRL+N) and paste the url. Then click on Video->Videotrack->deactivate.
Note that this will still stream the whole video, but it will not display it.
Comment: A useful alias: `alias youtube-dl-audio='youtube-dl --ignore-errors --output "%(title)s.%(ext)s" --extract-audio --audio-format mp3 --audio-quality 0'`
Answer: If you have vlc and the text-based browser lynx (both available from Ubuntu's repositories), there is a neat trick you can use to stream video from a commandline.  The command I use will do a search and create a playlist of the first page of results which will play in vlc.
I created a simple script to handle the tricky syntax.  The script is:
#!/bin/bash
lynx -dump "https://www.youtube.com/results?search_query=\"$1\"" | egrep -o "http.*watch.*" | vlc -

So, if you name the script, say stream_youtube, you can just enter "stream_youtube "search term"
I just tried it out after not using it in a while, and noticed a couple of errors popping up in a window that I never saw before, but in spite of that annoyance, it still worked.  Someone might find it useful, or at least interesting. :-)
Answer: You can pipe the output of youtube-dl with your preferred format into ffplay without showing any windows.
example:
youtube-dl -f 251 https://www.youtube.com/watch?v=vdRJMuOFO88 -o - | ffplay -nodisp -autoexit -i -

this is done via shell but you can do it programmatically if needed since both apps have python bindings.

Stream audio from youtube


Let G be a nonabelian group of order 10 prove that G contains an element of order 5 and five element of order 2

Question: Because order of element divide order of the group,the possiblility of order of element is 1,2,5,10.
Frin this ,it must contains element of order 5 and 2.
But I can't prove that it must gaurantee five elements of order 2 .Anyone can give a hint ?
Comment: Hint: How many Sylow 5 and 2 subgroups it **must** have?
Answer: Hint: Look at Sylow $2$ and $5$ subgroups.
EDIT: Also notice that the statement of your problem follows trivially from Cauchy's theorem which says that if $p$ is a prime and $p$ divides the order of a group, then the group contains an element of order $p.$
Answer: By Lagrange, the possible orders of the non-identity elements of the non-abelian $G$ are $2$ and $5$. Not all the nonidentity elements have order $2$, otherwise, $G$ would be abelian. So $G$ must contain an element "$a$" that has order $5$. Therefore the elements of $G$ that are of order $5$ are $a, a^2, a^3, a^4$. To eliminate the possibility of there being any others suppose that there exists $b \in G$ such that b does not belong to $\langle a \rangle$ and $|b|=5$ since $5$ is prime no power of $b$ will belong to $\langle a \rangle$. Now consider the two cosets $b^2 \langle a \rangle$ and $b^3 \langle a \rangle $. Since $|\langle a \rangle|=5$ there are only two distinct cosets one of which is $\langle a \rangle$. Therefore $b^2 \langle a \rangle = b^3\langle a \rangle$ which implies that $b^2b^{-3} \langle a \rangle = \langle a \rangle$  implying $b^2b^2 \langle a \rangle = \langle a \rangle$ implying that $b^4 \in \langle a \rangle$ contradiction. The conclusion is that $4$ elements have order $5$ and $5$ elements have order $2$.
Comment: This did not copy right


How to block for open Web Shell in my CentOS 6

Question: I currently use mod_security in combination with maldec and block almost all attempts to upload shells, leading them to error 406. However, I found one "problem" if I upload Shell through an ftp client then I can use shell in hosting.  my question is how to block the opening of the shell even if uploaded via ftp?  any mod_security rule to use and if so what?  I also use cPanel
Comment: Can you provide more detail about what you mean by "opening a shell"? I'm assuming this means opening SSH, or a reverse shell, like something that gives remote bash / powershell control of the machine?
Comment: @schroeder understood me correctly. I want to detect when someone connects to an unknown shell in an unknown location. Thanks u for your understanding. Webshell
Answer: ModSecurity is a Web Application Firewall. FTP is not Web traffic, HTTP and HTTPS are. This means ModSecurity cannot be used for filtering FTP traffic not can it be used to filter mail traffic.
Also, ModSecurity does not protect against misuse of hacked accounts or severe server misconfiguration in general. If somebody is able to use FTP to upload malicious code which then can get executed as part of the website (like a webshell) then this can only be done if you either allow anonymous upload to your web hosting (misconfiguration - just don't!) or that the username and password to your account is known to the attacker.
Comment: Then why did you mention FTP? Do you mean that you can upload a shell via FTP to the web directory and access it via the web? And you want to detect when someone connects to an unknown shell in an unknown location? The remedy for that would appear to be to not let FTP users have access to the web directories ...
Comment: @Квлади: There is no generic webshell. The parameters in the call of a webshell can be anything - it is fully up the malicious server side component how to interpret it. The command to execute can for example be "encrypted" (simple rot13 or variation might be enough) so that a simple pattern match will not work.
Comment: @Квлади: Essentially your question boils down to detect misuse of a compromised webserver account using ModSecurity. But this is the wrong tool for the job. Instead you should check the integrity of the server and not just rely on analyzing the network traffic to the server.
Comment: I I know what mod_security is.  I'm trying to create a rule that checks the file that opens for malware, for example: (but doesn't work) SecRule RESPONSE_BODY "@inspectFile /usr/local/maldetect/modsec.sh" \ "log, auditlog, deny, severity:  2, phase: 2, t: none, status: 403, msg: 'Malicious open Identified.' "
Comment: @schroeder understood me correctly.  I want to detect when someone connects to an unknown shell in an unknown location. Thanks u for your understanding


Is there any way to access Ultimate Member's custom fields?

Question: Ultimate User allows you to create custom fields in the register page.  I have added address and phone.  Where do they go?  You cannot edit or even find them in the back end user interface.  I added them so that they could appear in the user directory listings and cannot find any way to edit that listing or find the fields.
Comment: They probably go in the user meta table if it's data specific to a user. I imagine the documentation for that plugin will tell you what the key names are, or you can use `get_user_meta` to fetch all meta data for a user, which will also tell you what keys the data is stored under.
Answer: I can confirm that the values are saved in the User meta table as I have been working on the same exact thing. meta_key contains the name of the input (case sensitive) and meta_value the actual value. User-ID is also a column, so, theoretically, you can get all the values for a certain user. I'm still working on this query so I can get the data for each user on a row.  We are also using the paid plug-in WP Data Tables to display the data from Ultimate Member.
Comment: Lisa, I have found the same thing.  The user_meta includes all of the users that I imported through a CSV file.  I created a short code and experimented with that to access each of my fields.  The next step will be to replace their template with my own to get my directory listing in the desired format.
Answer: Follow this link, https://gist.github.com/magnific0/29c32c7dabc89ab9cae5, and it will show you how to adjust your functions.php file in your themes folder to show the custom UM metadata under the user menu.
works like a charm :)
Comment: Yhanks for posting this.  It's better to actually post the code here (in case the owner of that code decides to pull it and then all we have here is a dead link.
Answer: Custom fields are recorded by Ultimate Member in the wp_usermeta table in this form:

So you can get the value of a custom field by using get_user_meta() function:
echo get_user_meta( $user_id, $field_id, true );

Answer: Ultimate Member has a function you can use to get the user meta data.
It is: um_user()
Usage:
<?php echo um_user( $data ); ?>

Example:
<?php
$custom_field_name = um_user('your_custom_field_name');
echo $custom_field_name; // prints the custom field data
?>


replacing wheels on a hybrid running on 700c

Question: Using 700c wheels limits the choice of tyres and when touring tyres might be hard to find. Is there a problem in using 26 in wheels instead.
Comment: Do you currently have disc brakes?
Comment: The biggest problem you have with switching to a smaller diameter rim is that if you have rim brakes they will no longer line up properly.   But note that 700c tires have been standard for touring for decades, and it's unlikely that touring-suitable tires will cease being available.
Answer: Brakes, tyre clearance, and lowered ground clearance are the three points.
If you have rim brakes, give up now.  They simply will be wrong, and buying super-long reach brakes will be expensive and won't work very well for leverage reasons.  Disk brakes may work okay, provided the rotor lines up, and your fork spacing is acceptable.
Tire/Tyre clearance should be okay because your new rim would be smaller.  However 26" tyres are often 1.75 or 2" so there may be clearance issues.  You'd probably have to go for smaller and not knobby tyres.
The bike will be sitting lower to the ground now too.  This will increase the chance of pedal strike going around corners, and the break-over height will be less, so you could strike the big chainring on the ground easier.
Surprisingly the wheelbase length will not change.  So "handling" should be unchanged.
Finally, the aesthetics will look somewhat weird, but that's only a visual thing.
Comment: Handling will change slightly, due to the change in "caster" of the front wheel.  Probably not enough to notice, though.
Comment: Oh yes quite right - the amount of follow or trail will decrease slightly so the steering will get slightly more twitchy/responsive and it would be minorly-harder to steer hands-free.
Answer: Handling will also be affected by having a lower centre of gravity. In theory the original wheel size would optimise the bike design and performance, though, as illustrated by Hicks and Criggie considerations.
Answer: Yes. Your frame has to be designed for the size of wheel that you are using. If you want to switch to 26 inch wheels, you are going to need to get a new frame.


Applying QGIS point cluster exception

Question: I have applied a point clustering effect on a layer in QGIS. What I'd like to be able to do is cluster on all features except the ones that I have a NULL value in an attribute. I can Categorize on feature when zoomed in using the rendered Settings, but there doesn't seem to be an option for categorizing data when clustered.
Answer: Actually, the cluster renderer does support categorized styles.
Next to the word Renderer there's a dropdown menu, where you can choose Categorized.

Under the Renderer type selection menu, click the button Rendering Settings... to access the normal layer style panel settings for a Categorized style.

Categorize by the field that has  values. Un-check the  category. Now the points with  values won't be displayed or included in any point clusters.

Here's a workaround I wrote up before I realized that the cluster renderer supports categorized styles:
Apply a Filter to the layer.
Here's a point layer with a 20 mm cluster distance:

Apply a filter "field" is not null"

Now the points with  values in the field are excluded from the point clusters:
Comment: the cluster renderer doesn't do that. you'll need to put the null features in a separate layer if you want them displayed separately.
Comment: this doesn't categorize the Null feature, it just doesn't show or count it in the cluster. I did mention this rendered settings in my question, and that wasn't the solution. There would need to be a categorize option on both the rendered and the point cluster basically. Where the cluster symbol is categorized and the renderer symbol is catgorized.

Applying QGIS point cluster exception


Logs in a separate database: would CiviCRM hangs if Logs database got corrupted?

Question: Well, subject has pretty much all of the question. Anyone with firsthand experience please?
Answer: Logs in a separate database is fine.  It's what we do at Veda to make the databases more portable and easier to backup.
Before CiviCRM 5.16, the log tables were in Archive format, which is prone to corruption. Starting with CiviCRM 5.16 the logs are in InnoDB format - but remain in Archive format if logging was already enabled.  If possible, switch the log tables to InnoDB format using the InnoDB Logging extension.
If you can't (size of the log tables will grow, especially when indexes are added) then yes, if the tables become corrupt the database transactions will fail but this is the same regardless of if the log tables are in the same schema or not.
Hope that helps


What could cause my dog to bite/pull her own hair out?

Question: The title pretty much says it - my dog, Chewy, has been biting and pulling the hair out on her front arms. Her name was given before this problem started. :)
It's not every day, and I cannot find a pattern but about every week or so I'll come home from work to chunks of hair pulled out around the house (normally all in the same area where she was laying), or wake up to what sounds like carpet being ripped out, which is an awful sound.
This has been happening for probably a year and a half.
About my dog
She is about 2.5 years old and is a Chow/Lab mix. She is honestly the nicest dog I have ever been around and NEVER gets aggressive (I only mention that because I know it is common for Chows to be aggressive/protective).
She was fixed as soon as she was old enough.
What we've done/tried so far

Keep her hair trimmed (especially around her arms/paws) because we thought that the length might be bothering her (and if it were shorter she might not be able to bite it as much). This had little to no effect.
Taken her to the vet, several times. The vet thinks Chewy has anxiety issues, which I agree with completely. We've tried a couple of different medications, the latest being Amitriptyline HCL, but haven't had any luck.

Her anxiety
We've moved 3 times since we've had Chewy, which I think has contributed to her anxiety of being in a new place. However, we've been at our new house since July 2014 so I would hope that wouldn't be an issue now.
She also has a fascination with being under things. Coffee tables, end tables, chairs, our bed, anything she can fit under, she'd rather be under it. She sleeps under our bed every night, and is under our coffee table in front of me as I type this. I've read this could have something to do with feeling protected.
I should also mention that she isn't shy at all. She has no issues with people or people coming over, etc.; she greets anyone and everyone pretty much immediately. That is why I am unsure about her feeling "unprotected" when she is always under something.
Allergies
I am not 100% sure that Chewy has allergies, but she might. When she was a puppy, our vet told us that she might have allergies and suggested we switch to a grain-free food. She's been on grain-free food ever since, although we aren't too particular when it comes to treats, etc., not having grains. She doesn't appear to have allergies to me (but I am not a vet and she hasn't been tested for allergies to my knowledge).
Bathing
I've also considered the fact that she might have dry skin, which could cause itching and thus her biting her arms. She honestly isn't bathed very often. She's an indoor dog but we really only bathe her when she absolutely needs it (i.e. gets muddy outside). I'm wondering if she needs to be bathed more often, possibly with a shampoo that can moisturize her skin?
Here is what her arm looks like right now, you can see the baldness (this is her left arm), although it doesn't look that bad right now:

Has anyone ever seen or heard of a dog doing this before or have any ideas/suggestions that we could try to get her to stop?
Comment: I'm wondering if there is a sensitive, yet moisturizing shampoo I could use, and then bathe her more often (once a week or so) if that might make a difference. I'm just looking for ideas of things to try!
Comment: You could try a raw diet for your dog. I am not an expert in dogs or raw diet but I have talked to experts on raw diet and read a lot about it and it seems to cure/help with a lot of issues in dogs. I am not saying it will cure whatever this is however it will lead to a healthier dog overall. I have my GSD on raw right now, started when she's 9 month old. Her coat is great, good energy, white teeth and never have the need to goto the vet
Comment: Can you tell us about her daily routine?  Is she getting enough exercise?  Some dogs chew out of boredom and frustration (which is a different type of anxiety).  Just a thought!
Comment: I think that may be part of it. We noticed it happens more when we aren't able to take her on walks as much. That's something we're trying to do more, is to let her get enough daily exercise and have been taking her to doggy day care a few times during the week as well to play with other dogs.
Comment: Have you considered using a treadmill? Some dogs become very comfortable using a treadmill as a source of exercise. My advice would be to seek a certified dog trainer in your area to get your dog accustomed to the device. Do not attempt this on your own.
Another suggestion, enroll your furry kid in an agility class. Great work out for both you and your dog and you can practice anywhere!
Comment: I think it's likely to be allergies since it sounds like it started around when you last moved.  I'd try cleaning more often, maybe hypoallergenic air filters, to see if that helps.
Answer: I'd recommend taking her to the vet immediately because often times this is a sign of a health condition that may need medical attention.  She may have pain or discomfort from a more serious problem, or it could be something very minor like a skin irritation.
This may be related to anxiety from the moving but since you moved a almost a year ago it may be something else in her environment that is causing this anxiety.  You may want to try giving her something much tastier to chew on besides her leg.  Just make sure that you give it to her before she starts chewing on herself and not as a reward for chewing on herself.
One thing that I have used that works is putting a kong toy in the freezer with peanut butter in it.  I find this will distract my dog for hours and may keep yours from resorting to chewing on her own fur.  Anything that you can do to distract her and keep her from doing the negative behavior will help.
Comment: Thanks for the input. We've taken her to multiple vets and discussed this, everything from anxiety, to allergies, etc. Nothing has really worked. Honestly, the best thing I've seen so far is when she can go to Doggy Day Care and play with other dogs *all day* so she is completely worn out when she gets home, thus sleeping all night. Most times when she does start chewing her arms, it's during the night.
Comment: And unfortunately, Doggy Day Care is too expensive to do every day, so my wife and I are trying much harder to ensure she gets proper exercise every day so she doesn't have all this built up energy at night.
Comment: Kongs are great for some many thinks. If your can't be bother cleaning one (their only fault is that they are really hard to clean inside), try getting an old butter/margarine plastic container and put some wet and dry food with some water and freeze. Doggy icebloke that keeps them busy for ages.
Answer: My sister-in-law's dog did this. It actually turned out that his paw was broken.
If you do decide to wash your dog once a month or more, you may want to look into the type of shampoo since the pH of their skin is determined typically by breed.
Comment: Related [Can I use human shampoo to wash a dog?](http://pets.stackexchange.com/questions/1938)
Answer: Our Schnauzer mix will pull out all the hair on his back he can reach when he is fed food with either corn or grains, we are not sure which.  We heard this was potentially the problem and switched, within a month the hair was growing back and he left it alone.  Several months later we forgot, and ended up with 1 bag of corn/grain containing food. (we mix two types of good quality dry food)  Right after that his hair started disappearing. (by being  pulled out)  Back on Corn and Grain free, and his hair grew back.
Give this at least a month, maybe 6-8 weeks.  No treats, as they often contain corn and grain, so stay away from them.  This is critical for smaller dogs, as it will affect them more as a percentage of body weight and food consumed.  If you can't live without feeding your dog treats, find grain and corn free ones and gradually get them switched over.  Stay away from made in China anything.
Another irritant for dogs that can show up as hair being pulled out is fleas.  We have found that Frontline works for us, or a generic equivalent.  A 3 month supply is fairly inexpensive if bought direct, and not through the vet.  (PetSmart, etc.)
I would go with the gradual food change to avoid diarrhea and see how that goes after 6-8 weeks.  If you notice fleas around, on your dog, or know they are present in your area then do both.
It is simple yet amazing the recovery.  Just as an FYI, we mix Nature's Recipe and Costco, both Lamb and Rice and Corn and Grain free.
Answer: Does she lick at the areas? A few suggestions that may be helpful:

Keep a diary of when you noticing her doing it. If it is a behavioural issue (which most of the time hair pulling is in animals), keeping note of what happened before or during the hair pulling may be helpful as you can then try to avoid that situation. Of course, this is only if certain situations are causing it.
Since it seems to be localised to just her arms, I'm lead to believe it may be a behavioural issue rather than a medical one, but with that being said, I don't want to rule out medical as I do not know what other behaviours she may be exhibiting, plus, dogs can get hot spots on only one part of their body.
Aloveen shampoo and condition are the bomb. http://dermcare.com.au/Products/Shampoo-and-Rinse/Aloveen.html They have a moisturising agent in them that helps with sensitive skin. You have to leave each one on for at least 5-10 minutes before rising otherwise, it won't work. Try not to wash her more than once every 10 days as washing a dog more than once a fortnight can strip their natural oils from their skin, causing them to be more itchy
A vension based food can help as it doesn't have as much protein, which can lead to skin irritation. I use http://ivorycoat.com.au/venison-adult-dog-food/
for my Lab and it has definitely help with her skin issues
Adding sardines to her diet is not only good for her gut but works wonders for a dog's skin. Salmon oil added to her food may help as well
Doggy day care can get expensive. Have you looked into Nose Work? http://www.k9nosework.com/ My girl was so exhausted after two hours on and off of doing this that she slept so deeply that night. Really gives their brain a work out and is great to watch

Hopefully some of this may help and hope your fur baby is feeling better soon
Comment: Thanks for all of the suggestions. We have her on an anxiety medication now, which seems to help quite a bit. However, she still does it every once in a while so I am definitely going to try some of these ideas out! Being winter now, I'm sure her skin is dryer than normal anyway.
Answer: I know that sound for sure. I have a Yorkie Poo and she does the exact same thing. So I took her to a dog dermatologist. Yes there is a such thing. Anyway she is allergic to her environment.  My dog hates to walk on grass and I have poison ivy in my yard which I believe she steps in so check your yard too.
He cleared up a bacteria and yeast infection she had with a special shampoo, two pills, and ear drops. After that my dog has to get an allergy shot each month. Her hair grew back immediately. And she stop lick/picking her paws. I hope this helps.


"Lowercase", "lower-case", or "lower case"

Question: Is it lowercase, lower-case, or lower case?
Comment: You write: *The name must be written in lower case*. But: *You must write your name in **lower-case** letters*.
Comment: @Irene do you mean as in `lowercase letters`, for example? Please explain what you mean by a modifier.
Comment: It is [lower case](http://oxforddictionaries.com/definition/lower%2Bcase?q=lowercase) unless it's a modifier.
Answer: Warren Chappell, Robert Bringhurst, and the printed Unicode Standard all use lowercase exclusively.
The only exception is when sorts are kept in two cases, and one puts some of those in the lower one and others in the upper.
Comment: @MatthewDoucette The exception is when is talking about the physical cases used by hand compositors working with real metal type.  The lower case is the case that holds the lowercase letters. For your purposes, there are no exceptions. Note that Unicode recognizes three cases: lowercase, uppercase, and titlecase, plus an internal one used by programs called foldcase.
Comment: I believe tchrist refers to the origin of 'upper case' and 'lower case', which is simply that typesetters kept the shouty glyphs in a higher drawer than those better-behaved.  See http://en.wikipedia.org/wiki/Letter_case#Terminology
Comment: Can you give an example of the exception?
Answer: Both lower case and lowercase can be seen in common usage, but it seems that lowercase became more popular after 1980s. You may want to check the following ngrams.

The same case is valid for uppercase.
Comment: Wow, this is very informative. The only unknown is if the usage of one or the other depends on context, as @Irene potentially suggested matters in the comment of the question.
Comment: @MatthewDoucette: If by "informative" you mean "misleading" then I agree with you. Did you wonder why "lower-case" flatlines, even though you know you've seen it in print more than, say, zero times? Because hyphenated words have to be separated into trigrams for NGram Viewer to correctly parse them. Here is [a link to a corrected graph](http://books.google.com/ngrams/graph?content=lowercase%2Clower+case%2Clower+-+case&year_start=1800&year_end=2000&corpus=0&smoothing=3). Big difference, huh?
Comment: I don't disagree with your general point, but you have to admit that if you did show faulty data (and before I called you out on it, you did), *even if the error is not deliberate*, your methods may be viewed with suspicion. What else isn't being shown? See my discussion of this whole NGram issue on meta. I have quite a burr under my saddle about this at the moment.
Comment: @Robusto: I appreciate your correction and thanks for sharing the true method for ngrams. Shame on ngram developers.
Comment: @Robusto, wow, I even went and tested to be sure `lower-case` resulted properly, and made the same mistake. What a horrible defect in Ngram Viewer, surely it has misled countless others.
Comment: @Robusto: I'll remove *lower-case* and add *lower - case* to my answer, but still this is not misleading. Usage of *lower-case* is still less than the other two.
Answer: Lowercase initially came from "lower case", referring to literally the lower case of the cabinet where this typeset was kept by convention. It has gone through the typical contraction from "lower case" to "lowercase" via the hyphenated form. The use of the word (lowercase) has seen a spike in usage during the last decade or so, as everyone needs to know (now) that passwords are case sensitive and that using uppercase is shouting. Back in the days of the Guttenberg press, a lot of print was all uppercase. Fashions change, as do fontfaces.
Answer: Dictionaries differ on how to handle this term—as a single closed-up word, as a hyphenated word, or as two separate words—depending on how the term is used and on when the dictionary was published. This answer looks at the evolution of spelling preferences given by two major U.S. dictionaries: American Heritage and Merriam-Webster.
The American Heritage Dictionary of the English Language, fifth edition (2010) recommends spelling the adjective, verb, and noun forms identically, as lowercase:

lowercase adj. Of, printed, or formatted in lowercase letters. | tr.v. -cased, -casing, -cases To put (type or text) in lowercase letters. —lowercase n.

(It might for a moment appear that AHDEL is endorsing the hyphenated verb forms lower-cased, lower-casing, and lower-cases, but the hyphens in this entry are simply there to avoid respelling lower at the beginning of each of the three verb forms. In like manner, the dictionary's entry for backtrack—which the dictionary defines only as an intransitive verb—gives the relevant forms as -tracked, -tracking, and -tracks.)
Just ten years earlier, however, The American Heritage Dictionary of the English Language, fourth edition (2000) listed lower-case as a common (and acceptable) variant for both the adjective and verb forms of the term (although not for the noun form):

lowercase or lower-case adj. Of, printed, or formatted in lowercase letters. | tr.v. -cased, -casing, -cases To put (type or text) in lowercase letters. —lowercase n.

The third edition of AHDEL (1992) offered the same spelling and punctuation options as the fourth edition. But the first edition (1971) did not list the closed-up single-word spelling at all:

lower-case adj. Abbr. l.c. Printing. Of or pertaining to small letters as distinguished from capitals: a, b, and c are lower-case letters. —tr.v. lower-cased, -casing, -cases. To set (type) in lower case. —lower case [n.]

Thus, over a 40-year span, AHDEL's preferences for spelling the term run as follows:

as an adjective: lower-case (1971), lowercase or lower-case (1992 and 2000), lowercase (2010)
as a transitive verb: lower-case (1971), lowercase or lower-case (1992 and 2000), lowercase (2010)
as a noun: lower case (1971), lowercase (1992, 2000, and 2010)

The evolution of spelling and punctuation preferences for the term in the Merriam-Webster Collegiate Dictionary series is far more abrupt, although it starts slowly enough. The first edition of Webster's Collegiate Dictionary (1898) defines the term exclusively as an adjective:

Lower-case a. (Print.) Pertaining to, or kept in the lower case; — used to denote the small letters, in distinction from capitals and small capitals.

Clearly, the First Collegiate views lower case as the proper spelling of the noun form and lower-case as the proper spelling of the adjective form.These preferences persist though the second (1910), third (1916), and fourth (1931) editions. The fifth edition (1936) maintains the same preferences, but adds an entry for lower case as a noun form:

lower case Print. a See CASE, n., 6 ["Print. A shallow divided tray for type. The upper case contains capitals, accented and  marked letters, etc.; the lower case contains the small letters, figures, etc."]. b Print in small letters. Abbr. l.c.

This interesting explanation of "upper case" and "lower case" had appeared in the entry for case as a noun since the third edition of Webster's Collegiate Dictionary, but was not cross-referenced in the entry for lower-case as an adjective in either the third or the fourth edition.
The sixth edition (1949) repeated the fifth edition's entries for lower case (noun) and lower-case (adjective), but appended to the latter an entry for lower-case as a verb:

lower-case adj. Print. Pertaining to, or kept in, the lower case; small (not capital); as, lower-case letters. —v.t. To change to small letters.

The Seventh Collegiate (1963), taking its cue from the revolutionary (relatively) descriptivist adopted by the full-size Webster's Third New International Dictionary (also 1963), changed the spelling preference for all three forms:

lowercase adj {fr. the compositor's practice of keeping such type in the lower of a pair of type cases} of a letter : having as its typical forms a f g or b n i rather than A F G or B N I — lowercase n
lowercase vt : to print or set in lowercase letters

All subsequent editions of the Collegiate—the eighth (1973) the ninth (1983) the tenth (1993) and the eleventh (2003)—have adhered to the seventh edition's preferences. So the progression of orthographic preferences in the Collegiate Dictionary series runs as follows:

as an adjective: lower-case (1898, 1910, 1916, 1931, 1936, and 1949), lowercase (1963, 1973, 1983, 1993, and 2003)
as a transitive verb: lower-case (1949), lowercase (1963, 1973, 1983, 1993, and 2003)
as a noun: lower case (1898, 1910, 1916, 1931, 1936, and 1949), lowercase (1963, 1973, 1983, 1993, and 2003)

Interestingly, although Merriam-Webster Online likewise endorses lowercase as the preferred spelling for the term as an adjective, a verb, and a noun derived from the adjective, it also includes an entry for lower case (two words) for the historical sense of the term as a case of type containing small letters:

lower case noun : a type case containing lowercase letters and usually figures, punctuation marks, spaces, and quads

The upshot of this historical assessment is that, in the United States, lower case (noun) and lower-case (adjective) were the preferred spellings through the first half of the twentieth century, joined by lower-case (transitive verb) by 1949. In 1963, however, Merriam-Webster came out four-square for lowercase for all three forms. American Heritage opposed the closed-up one word spelling lowercase in its first edition (1971), but approved it as an acceptable variant in its third edition (1992), and embraced it to the exclusion of the hyphenated and open forms lower-case and lower case in its fifth edition (2010).
Comment: An open and shut case.
Answer: All are okay – I've seen English teachers use all three, so it must be fine. I think it just depends, maybe, on where you live. In the United States and other countries, people use lowercase more often, but in other countries they might use lower case or lower-case most often.
I'm pretty sure that it doesn't matter. All ways of writing it are okay. Since lowercase is used more often in the United States, it may be helpful to use lowercase, but if you live in someplace where most people use lower case or lower-case, you should probably use the way that people spell it where you live. Nobody will mind, most likely, and people will understand it all three ways, but if you spell it in a way that most people from where you live don't spell it, they may use it as bad grammar and it may not bode you well if you are doing something formal. Just try to spell it the way that most people from where you live spell it.
Comment: Welcome to ELU! Do you have any research to back up your answer?
Comment: This answer is very... repetitive. It seems to basically say the same few things (i.e. that all 3 ways are okay, and that it "might" vary by region) several different ways, without actually providing any sources/citations to back up its primary claim(s).
Answer: According to oxforddictionaries.com, "lower case" is used in British English, and "lowercase" is used in American English.


As a Canadian citizen and Italian Resident, do I need a visa to carry out remote contractual work for a UK company?

Question: Are there any visa requirements as an Italian resident who would be working remotely from Italy but for a UK company? The work would be part-time and of a consulting nature. If so, I would appreciate any links to official documentation on the rulings for this case. Thank you.
Answer: You would need a UK work visa to work in the UK.  You won't be working in the UK, so you won't need a UK work visa.
If you are not yet authorized to work in Italy then you will need to get an Italian work visa or work permit or other authorization.
Your client in the UK may be reluctant to pay you directly for fear of falling afoul of labor laws and, especially, payroll obligations.  If that is the case then you will need to set up a company or register as a sole proprietor (details vary in different countries) so you can handle those responsibilities yourself and establish a business-to-business relationship with your client.


Disciplining a special needs child

Question: What should a parent keep in mind when it comes to discipline and children with autism? What about children with learning disabilities?
Comment: As some one who worked at a school for kids with a variety of social, behavioral, and learning disabilities I'd have to say it depends greatly on the specific disability, goal for behavior, age and for Autism (and other disabilities with spectra of ability), the age and level of functioning is also significant.  Can you be more specific?  This question is too broad as it is stated now.  Whole books are written on this topic for single disabilities alone.  I'd love to help with more specifics.
Comment: Maybe you want to define what you mean by discipline.  Are you talking strictly about punishment, or are you talking about discipline in the sense of "train up a child in the way he should go" which is far broader than punishment for wrong actions?  Also you may want to clarify how your Christian beliefs relate to your question - Christianity may impact what you want to teach your child, but you haven't clarified how here.
Comment: @justkt Yes, I'm speaking of Proverbs 22:6 which you quoted: "Train up a child in the way he should go; even when he is old he will not depart from it" As a Christian, I believe discipline is more than just punishment for wrong actions. I believe that wrongful actions are sin and deserve to be punished but in the same light, God is gracious to forgive sins if one believes in Him.
Comment: I have to agree this is overly broad.  If you can edit this to indicate specifically what you are asking (from the perspective of what you mean regarding "special needs" or "discipline"), we can reopen, but I'm going to support the other users who have voted to close for now.
Answer: It's important to understant the developmental progress of a child so that you can be sure to set appropriate expectations. For example it's not appropriate to expect a child with the developmental capacity of a 2 year old to sit still or be quiet. Talk with your doctor about the behavioral, emotional, adaptive, linguistic, and motor development of the child so that you can be sure what kind of behavior would be reasonable to expect. Know the child's developmental age.
Timeouts work for most children over age 18 months, with 1 minute per year of developmental age. For example, if the child has the mental capacity of a 6 year old, they would get 6 minutes of time out. Check out the link for how to do a time out.
The key is to be consistent.
Answer: You discipline them the same as your other kids.  Some techniques work better than others, but that's true of any child, and you can't generalize what techniques do or don't work to all special needs children.  Mostly what you change is your expectations.  Things take a lot longer to learn and you have to cut them extra slack.
Comment: So are you saying discipline them the same, or are you saying cut them some extra slack?
Comment: What I'm saying is there's no magic system of rewards and punishments that only work on kids with special needs.  You use the same types of punishments and rewards, but set the rules appropriately lower.  My 8 year old with cerebral palsy has approximately the same rules as her 3 year old sister, except for chores like cleaning up toys she can't do because she is physically unable.  Our 5 year old is held to a higher standard now, but had the same expectations as his sisters when he was 3.

Disciplining a special needs child