Clicking on links

Question: We are often warned about clicking on links in emails from unknown senders. That got me to wondering about other situations. For instance, you are searching the web looking to purchase an item and several sites come up. You go to a site that you never heard of and click on a link to find out more about a particular item. Does that expose you to the same risks as clicking on a link in an email?
Answer: Email links generally carry the risk of getting phished, whereas clicking on web links is more amenable to getting scammed in general or, in limited scope, clickjacking and XSS. Rule of thumb is to never click on advertisements, always click on "official" links (make sure that the domain is valid!), and generally be very vigilant with entering credentials and bank info.

Clicking on links


How to disable HDMI port?

Question: Is it possible to disable the HDMI output in Windows, so that, when you connect an HDMI device, the system doesn't react to it?
There's usually a second screen connect via HDMI, but I just want it to show information when I need it. Now, it always shows a part of the screen, so I have to switch to "Only this pc" in the Project (Windows+P) menu. That asks too much time, as I have to do it each time.
So, is it possible to disable the HDMI output and, if so, how?
Comment: No, it's not really possible for the PC to guess what you want or don't want at all times.
Comment: Funny how nobody seems to have understood thw question, but people still replied. As far as I understand you need a quick way of disabling or re-enabling the hdmi port on your computer so that you can easily activate it when you need it. Not a BIOS dependent solution that takes longer time. Im looking for the same thing. Did you find something?
Comment: AFAIK, it's not possible to disable an HDMI port since it's kernel/driver controlled _(it's not like a USB port that can be turned off at the OS level)
Answer: I know this is an old post but answering for anyone that needed it as I did!
If you have it, the Nvidia Control Panel will allow you to select which monitor you would like to use and deselect those you are not using!
If you use a different GPU perhaps there is a Graphics Card Controller that does the same.
Fantastic in my case for switching from my work monitor to my Tv when needed without pushing the graphics card to run both at once.
Comment: I don't think that will do what OP wanted. Windows will remember display layouts with known displays, but if a new HDMI display comes around it will probably still be automatically activated.
Answer: This is a bit of a hack,but it might work.
If you bought a 2 port HDMI switcher.
You could have the switch set on 2 until you need the port.
Anything on port 1 would be invisible, and port 2 would be empty so windows won't detect anything.
Now that means buying a hdmi switcher, but only you can decide if you want to go that far.
Answer: In Windows 10 and later (possibly earlier), monitor configurations are persisted. So you can connect the monitor, got to display settings, under Multiple Displays choose Disconnect this display, and then monitor will remain disconnected whenever you connect the HDMI - until you change the settings again.
Answer: If you just want to disable it permanent your answer is in the computer BIOS.
You have to access your computers BIOS and set the HDMI Device state to Disabled of Off.
Cheers!
Comment: This isn't a universal solution. It's only possible with some firmware. It's also only possible with integrated graphics.
Answer: As above, the BIOS settings allows you to set the state of your HDMI device. The easiest way to get there is from the Settings app on your PC (assuming Windows 10). Choose Update and Security > Recovery > Restart Now (under Advanced setup). Your computer will restart and show a blue screen with an option called Troubleshooting. Click that, then go to Advanced options > UEFI Firmware Settings > Restart.

Navigate to settings. You can get there by clicking the gear icon on the Start menu.
Select Update & security.
Select Recovery from the left menu.
Click Restart Now under Advanced startup. The comptuer will reboot to a special menu.
Click Troubleshoot.
Click Advanced options.
Select UEFI Firmware Settings.
Click Restart. Your system will restart and take you to the BIOS.
  How to Access the BIOS on a Windows 10 PC from Laptop Mag

There is also a keyboard shortcut you can use to go straight to BIOS when you first boot your PC. A list of these can be found here.
Comment: Please include all relevant information from linked pages in your post. That way, the answer will stay complete even in the future when other resources become unavailable.
Comment: Is there a way to do it without the bios. I am a blind user and cannot use the pc's bios...
Comment: @JordyDeweer - No.  If the firmware has the ability to disable the HDMI port, then it is going to be in the firmware, but honestly the reason you want to disable the HDMI port in the first place isn't clear.

How to disable HDMI port?


Why are metals opaque?

Question: Why are metals opaque? Is it due to the free electrons in a metal or a material's intrinsic properties?
Comment: In a book , it is written it is beacuse of the free electrons in a metal which absorb the incident radiation . But insulators (wood) are also opaque . They are not conductors or have free electrons .
Comment: you asked conducting metals.  But, all metals are conductors
Comment: Basically I'm asking when a material is opaque or transparent . Does it have to do anything with free electrons ?
Comment: Related: https://physics.stackexchange.com/q/72368/2451 and links therein.
Comment: Wood is actually transparent. Mostly fibers used to make paper, mostly cellulosa, the stuff that cellophane is made of.
Comment: https://en.wikipedia.org/wiki/Transparency_and_translucency#Transparency_in_insulators
Answer: Metals have a high concentration $n$ of quasi-free electron constituting an electron plasma. This results in plasma frequencies $$\omega_p=\sqrt \frac {ne^2}{\epsilon m_e}$$ which are typically between visible and ultraviolet light. Below the plasma frequency an ideal plasma neglecting collisions has a negative permittivity, reflects transverse EM waves perfectly and has imaginary wave vectors, i.e., purely exponentially damped waves. Only above the plasma frequency EM wave propagation is possible.  This can explain the opacity of metals in the frequency range of visible light and below.

Why are metals opaque?


Where did Tobi get his left eye from?

Question: Thinking back about Tobi's battle with Konan, he used Izanagi to escape from Konan's ultimate technique!
I searched through blogs and Narutopedia but couldn't get the source of his left eye, that he used to overcome Konan's ultimate technique.
Answer: Although it is not explicitly stated as such, he supposedly gathered several Sharingans during the Uchiha incident.
This "cupboard" in the room where he operated on Sasuke is probably where he preserves his "collection". He has been showed standing next to it on one or two other occasions.
Comment: Was he the one accompanied itachi in 'uchiha pursuit'
Comment: if yes then it is very much clarified ..
Comment: It is known that Itachi knew Tobi and his grudge for the Uchiha clan before he did the massacre. Also, it was essentially Danzo who ordered Itachi to massacre the clan. When Tobi meets Danzo during the Five Kage meeting, he remarks that they had not met since the Uchiha incident, which implies that Tobi was also somehow involved with it. We later learned that Danzo gathered 10 Sharingans during that massacre, so Tobi probably took the rest.
Answer:

So here we have to look at Tobi's left eye. The one he used for izagani. I researched a bit into it and looked into Sharingan user eyes since it struck me as very familiar. I realized Madara's EMS looked very similar to it, and I decided to look up his brother's eyes since EMS is a combination. The bottom picture of the Sharingan eye is Madara's brother, Izuna Uchiha, eye. Taken that Madara saved Obito/Tobi, I believe that when Madara died, he took his eyes. However this is a theory, but the eyes are very similar.
Comment: You'd do a bit better with more evidence than just a picture.  There's nothing to suggest that this isn't an error in how the manga itself was drawn, and I don't think that this particular scene when animated indicated this specific tomoe pattern.

Where did Tobi get his left eye from?


Why is $\binom{n}{k}$ for fixed $n$ not Gosper summable?

Question: I am trying to understand the book A = B which has many much more complicated expressions which are Gosper-summable but then on p. 102 he states $\binom{n}{k}$ for fixed $n$ as a function of $k$ is not Gosper-summable. How can this be? Can someone show why it is not Gosper-summable?
Answer: Gosper's algorithm can only find a formula for
$$
   S(k) = \sum_{i=0}^k \binom ni
$$
if it turns out that $S(k)$ is itself a hypergeometric term: if $\frac{S(k+1)}{S(k)}$ is a rational function of $k$.
However, for $k \ge n$, $\frac{S(k+1)}{S(k)} = \frac{2^n}{2^n} = 1$, so if it were a rational function, it would be equal to $1$ everywhere (aside possibly from places it's not defined). That's not what it does. Therefore it's not a rational function, $S(k)$ is not a hypergeometric term, and a series with partial sums $S(k)$ is not Gosper-summable.
In general, whenever we have a series with only finitely many nonzero terms (as we do here), it can only be Gosper-summable if the infinite sum over all terms is $0$. In that case, we can't carry out the argument above, because we can't say "our rational function is equal to $\frac{0}{0} = 1$ at infinitely many points".
Comment: Why is it not possible to assume only the values of k>-1,k<n for integer k ? For example k mod n. I am not too good at theoretical math but i guess that would not be a valid field? and/or it has divisors of zero which would be a problem? Anyway back to the normal field I suppose 1/k! is also not gosper summable ?
Comment: When you say for the same reason can be more specific. In this case we don't have only a finite number of non 0 terms. Or is it the case that the sum over all terms to inf be 0 ? It doesn''t seem that should be the case as it seems would be much too restrictive.
Comment: @userMisha_LAVROV For some reason my last comment disappeared . When you say for the same reason could you be more specific. For example in the case of 1/k! it is not the case that only a finite numbers of terms is non 0. Or would you say the problem is the infinite singularity at k=0 ?
Comment: Sorry, my previous comment was just nonsense. I'd have to think more about what's going on with $1/k!$.
Comment: I suppose you could argue that $\frac{S(k+1)}{S(k)} = \frac{e + O(1/(k+1)!)}{e + O(1/k!)}$ approaches $1$ much more quickly than a rational function ever could.
Comment: @userMisha_LAVROV  More specifically why is $\sum_{k=1}^m 1/k!$ not gosper summable?
Comment: I just answered that! I don't want to go into lots of detail in comments, so ask it as a separate question if you want more details.
Answer: I try an alternate proof and write the sum as $\sum_{n=0}^m \binom {p}{n}$ for $m,p$ arbitrary large
positive integers $p\!>\!m$. Per the book A=B denote the summand by $t_n=\binom{p}{n}$ and $r(n)=\frac{t_{n+1}}{t_n}=\frac{p-n}{n+1}$ here. On p75 eq.(5.2.3) is stated assume can write $$r(n)=\frac{a(n)c(n\!+\!1)}{b(n)c(n)}$$
where $a,b,c$ polynomials in n and $ gcd(a(n),b(n\!+\!h))\!=\!1$ for all integers $h\!>\!-1$ and I find $a\!=\!p\!-\!n,b\!=\!n\!+\!1,c\!=\!1$ as the lowest order or only? possibility. Anyway it goes on... and per p76 it requires a finite polynomial solution x to $$a(n)x(n\!+\!1)-b(n\!-\!1)x(n)\!=\!c(n)$$
which in this case is $$(p-n)x(n\!+\!1)-nx(n)\!=\!1$$  and if such a polynomial $x(n)$ cannot be found then Gosper's method fails.
Though I can't prove it rigorously it seems in this case such a polynomial does not exist for the only possibilities would be $x=cst$ which obviously does not satisfy or else of order >zero in which case the coeff. of the highest order term on lhs would have to be 0 which is not the case either so conclude Gosper's method fails so $\sum_{n=0}^m \binom {p}{n}$ is not Gosper summable ? For more detail the book is on the internet and can be found by searching 'book A=B' eg on google. By the way per Gosper's basic method it must
satisfy 1st order recurrence. It seems to me for most practical applications the cases where Gosper's method works are very limited.


Invite visitors to sign up for email from landing page

Question: Is it a good idea to ask visitors to subscribe for email when they land on your site? A lot of eCommerce sites do it and we are considering it for our site. However I need some input based on experience or data to help us decide if it is worth doing. Does it turn away potential customers or are they ok with just closing the invite and moving on?
Any idea on the response rate to these invites?
Comment: Why do you want them to subscribe in the first place?
Answer: I think the answer depends on your goals. In my experience working on ecommerce sites, prompting for an email address on a landing page increases the number of addresses you collect which (when coupled with effective email marketing) increases engagement and conversion. The downside is user aggravation and annoyance and of course, making your site feel more down-market.
A couple of suggestions:
Make sure that the button to close the invite is usable on phones and tablets - make the target big.
Consider showing the invite after the user has been on the site and browsed a few pages. "Would you like more of this great content?" is a lot better than "Give me your email address" before the user can see what you offer.
Only do it once.
Answer: Its ethical (and legal) to have a user opt-in voluntarily and then be able to opt-out if they want.
The best way to get experience or data for your application is to A/B test a prototype or ask user impressions with a cognitive walkthrough or think aloud exercise.
You raise a great question about how appropriate it is for an initial page. It depends on goals. Hypothetically, it is a bad idea to put an email sign-up in a sales funnel because it may siphon away from purchases. It might also turn an otherwise pointless page into an invaluable lead generating tool - making the ROI junkie salivate.
Good luck, Ken
Answer: I think you should add it at the end of the article the user was reading; because he was interested enough to finish the article and still stick around.
Asking them to subscribe when they don't even know what you've written makes them trust you less and may result in increase in the bounce rate of your website(Because Pop-Ups scare people regardless of what they say).


'It's okay, It's my first time. ' Does it make sense?

Question: I want to get a tatoo with the phrase "It's okay. It's my first time." But I'm not sure this sentence makes sense. It means It's my first life, so It's okay to be a little clumsy. But I am worried that this phrase is awkward and might be taken in a wrong way.
Comment: The way most English speakers would receive this is as :"Don't worry about fumbling, I was a virgin too". This is very likely not what you intend on your tattoo.
Comment: +1 for checking grammar before getting the tattoo, very wise
Answer:
It's okay. It's my first time

It's very clumsy and highly ambiguous. I get that you might enjoy explaining your tattoo, but there are so many meanings people might assume before your intended meaning of "It's my first life, so It's okay to be a little clumsy". They might think you are referring to your first tattoo. You haven't said where the tattoo will be, but if it was in an intimate place, someone uncovering it might think it was your first time... you know.
How to make it better is a matter of opinion, but here's what I think is wrong with it:

you use "it" twice, this makes it clumsy.
"It" should ideally be something already mentioned, or something that will be understood by all parties. You need to make the intended meaning clearer.
you've made it two sentences, both starting with "it". It could be one sentence, two clauses.
"it's okay" can be used to soothe someone, or offer commiserations as well as say that things are 'fine'. It might be best to use a different idiom that conveys the nonchalance you intend.
to be honest, the whole concept is a bit shaky. If you believe in reincarnation (ie that you will have another time around), how can you be so sure that this is your first time? Something to think about before you get it inked on your body.

How about instead:

I'll get it right next time around.

It's short. It's nonchalant. It could be a little bit mysterious, but I don't think there are any unpleasant meanings that could be assumed from it. It doesn't presume this is your "first" time. Saying "next time around" is more idiomatic in the context of having another try at something.


Why did Calaf offer Turandot the deal?

Question: In Puccini's Turandot, after Calaf successfully answers her riddles, Turandot begs her father not to make her marry him. (That's pretty rich given that the opera implies that she had at least 26 people killed for not being able to answer the riddles, but that's an issue for a different question). In response, Calaf states that he wants her to love him too and offers to call the whole thing off if she can discover his name by dawn. Why does he offer this? I understand that he wants her to love him, but why does he think that that would help?
Answer: In one sense, it's a counter to her own riddles: for the suitors, who were unable to answer Turandot's riddles, their punishment is death. Calaf however knows that Turandot's greatest fear isn't death, but to submit herself to a foreign suitor- and hence, or so she believes, risk reliving the tragedy which befell her ancestor, Princess Lo-u-Ling, who ruled peacefully until one day she was raped and killed by a foreign prince ("In questa reggia", from Act II) - and hence, he offers her a chance to save herself from her fear as well with a riddle, just as she offered her suitors a chance.
When Calaf sees that Turandot loathes him and begs her father to annul the marriage, he realises that should he take her then and there, he would be doing it as an act of force in some sense. So when she asks of him, Mi porterai con la forza?, he tells her instead ("Tre enigmi m'hai proposto") that he wants her "burning of love" for him (ti voglio ardente d'amor). He offers her a chance to refuse him once again, and puts his own life on the line in order to show her that his love is truly sincere and genuine, in a way that fairly honours her agency.
Comment: Excellent answer, thanks. Welcome to the site by the way.
Comment: Thanks! I'm glad I was able to help.

Why did Calaf offer Turandot the deal?


How do I restart Synergy in Mac OS X

Question: I have the free (aka old) version of Synergy installed on macOS Sierra. For some reason all the options in the drop down menu are greyed out and it won't connect to the server. How do I restart Synergy?
Answer: One solution:

Find the Synergy process in the Activity Monitor.
Hit the X to quit the process.
Cmd+Space and search for Synergy to start it again.
Answer: For Synergy 2:

Sometimes the background service can get into a bad state. This is most commonly caused by either sleep/resume, a change in IP address, or just random bad luck, but other factors can affect it as well. We're urgently working on a fix for this problem.
In the meantime, please could you open the Synergy config app and press the key combination Shift+F5 on both computers. This will restart the service, and you'll have to click Retry afterward. You may need to repeat the key combination it a few times, but if that doesn't work, you can also try restarting your computers. This should solve the problem, but if not, please send me your most recent log links so we can try some more solutions.
If that doesn't work, please contact support.

https://symless.com/synergy/help/connection/background-service
Edit:
After viewing the Synergy processes in the activity monitor as Philip suggested, I found multiple synergy-core processes. Terminating them all solved my problem!

How do I restart Synergy in Mac OS X


Statics Question

Question: I have shared the question statement, its diagram and my solution but my solution is wrong and I have no idea why is it wrong, please help me out.
Comment: I never thought in any of my wild dreams to help DemonLordKing to solve his static homework but here you go : Instead of setting the maximum values, try to find the forces in any member in function of **P**, then  fill the maximum allowable stresses in the most critic member. If i calculate everything correctly then it should be something around 5.19
Comment: Thanks a lot, and its not my homework, im solving questions on my own to practice and learn the concepts, and I understood that we have to take the members in function of P but I need to understand why my solution is wrong?
Comment: Suppose the maximum stress is $8$ kN in DC, then it implies the stress of say $\sigma$ > $8$kN in the CE if recall correctly or some other member, that's why your solution is wrong, the real stress in DC is not $8$ kN or $6$kN. Your assumptions are wrong.
Answer: you should think first about the whole structure, and then look into each joint. Apply the sum of the forces on the horizontal, the sum of the momentum and vertical forces must all be equal to zero to the structure as an object, similar to what you have been doing all the course.
I have found a mistake on your solution since you didn't consider the first gender support in $E$. Correct that and try to express, in the equations of ballance, expressions for the reactions relative to $P$ from the equations of equilibrium of the whole structure. This will result in a problem which will be in function of $P$. In this step $R_a$ and $R_e$ will be, if my calculations are correct, $3P$ and $2P$ in modulo, respectively.
Then, and only then, go to the joints and do their ballance of equilibrium. As it is all in function of $P$ you then separate those suffering compression from tension. Among those suffering compression, which is taking the higher force? Equal it to $6$kN. Among those suffering tension, which is taking the higher force? Equal it to $8$kN. The smallest of the two is the correct value of $P$, since the highest will cause a violation in the other restriction.
Comment: The reactions will actually be $P$ and $-2P$, but otherwise good answer.
Answer: Using method of joints we can calculate the maximum compression according to the values given being 6kN. As that strain is greater than 8kN we should assume 6kN to be achieved first.
Force P should not exceed the maximum compression value of 6kN at the vertical component of the truss CD.
$$6 \sin 60=3 \sqrt {3}=5.196kN$$
There is no way that tension can even come close to 8kN in the truss without exceeding the 6kN compression.
Comment: No, you can't assume that. You must calculate the tension in terms of P that each link can sustain. You can make deductions about pairs of links from symmetry conditions that reduce the number of calculations. For instance, the reaction at A must be P, and the reaction at E must be -2P. Then we can use bilateral symmetry to reduce the number of links from 7 to 4, and simplify the vertex formula to trivial equations if taken in a sensible order.
Comment: I checked it with computer software designed for this problem and it is accurate.
Comment: But by changing the angles a little, it wouldn't be. You can have a quite similar looking truss that would be limited by tension. The fact that you guessed correctly isn't the point. Your reasoning is faulty. You must do the calcs and apply reason. That is what they are trying to teach here.
Comment: 6sin90 is the max vertical force allowable which means that F_p would be equal but opposite and therefore 6kN whilst the horizontal members would be zero length.

Statics Question


Should I use the manufacture's print driver instead of secure AirPrint?

Question: I've noticed that macOS appears to default to using secure AirPrint as it's printer driver over the manufacture's printer driver. Any reason why I should choose one over the other?
Answer: Consider this.
In the near future, there will be a macOS update. Your printer manufacturer may or may not release a timely driver update that matches the updated OS. As a result, your system may become unstable, not be able to print or worse.
My strong suggestion is that, unless there's some mission-critical functionality you need, it's always best to go with the built-in drivers. With it, there's a much higher probability that your system will remain stable through multiple OS updates.
Comment: Exactly what happened to me with Catalina. Xerox promised drivers and 5 months later it's still coming "soon."


Everytime I dismiss a roommate a different roommate is in my apartment

Question: So since I decided to plan to move into an the apartment with 2 adults, 1 baby and 1 kitten. So, my family went to their apartment and there was someone living there trying to go to bed. I dismissed the roommate but 2 seconds later a different roommate is back again! I can't even turn off roommate services and the button is gone too.
Do I really need a roommate?
Answer: I had the same issue about a year ago. No, you dont need a roommate  if you don't want one. When your roommate option went away had you done a cheat before then? If so, it has glitched your options. While cheats are great and help more often than not, they do mess with your game. You can go to your game options, settings, restore default. This will take the options back to the original ones. You will have to set them back to your preferences after the fact, but this should bring your "turn off roommate" choice back.
Hope that helps. ☺


Unstable Vector Bundles

Question: As a follow up to me other question, what can be said about unstable vector bundles? I know this is rather open ended, but what sorts of horrible things does having a subbundle of strictly greater slope imply?
Comment: A non-horrible thing: it has a "Harder-Narasimhan filtration" by smaller bundles, where each quotient is stable. Instead of making a moduli space of stable vector bundles, you could make a moduli space of vector bundles with fixed dimensions in the H-N filtration. See Atiyah-Bott's Yang-Mills paper for more.
Answer: Well, I don't know about horrible.  There's a lot you can say that's good!  I'll start rambling and see where I end up.
I'm going to pretend you said principal GL(n)-bundle instead of rank n vector bundle.  Same thing, really, since we have the standard representation.
The collection Bun(n,C) of all principal GL(n) bundles P on a smooth curve C is a very nice geometric object:  it's an Artin stack.  It's not connected; the different components are labelled by topological data, like the Chern class.  The tangent "space" (complex, really) to Bun(n,C) at a point P is naturally the derived global sections RGamma(C,ad(P)), where ad(P) is the associated bundle with fiber the adjoint representation of GL(n).  The zero-th cohomology gives the infinitesimal automorphisms and the 1st cohomology gives the deformations.  So the stabilizer group of any point V in Bun(n,C) is finite-dimensional, and the dimension of the stack is n(g-1) (by Riemann-Roch).  Bun(n,C) is smooth, and unobstructed, thanks to the vanishing of H^2(C,ad(P)).
Bun(n,C) has a very nice stratification, too.  It's an increasing union of quotient stacks [A/G] of projective varieties by finite-dimensional groups.  Roughly, A is the stack of pairs (P,t), where t is a trivialization of P in an infinitesimal neighborhood of some point in C.  Make the neighborhood large enough, i.e., r-th order, and you can kill off all the automorphisms of P.  Unfortunately, except for n=1, there is no uniform bound on r that works for all bundles.  So, Bun(n,C) isn't a finite type quotient stack.
You can also realize Bun(n,C) (homotopically) as the infinite type quotient stack of U(n)- connections modulo complexified gauge transformations.  That's what Atiyah & Bott do in their paper "The Yang-Mills Equations on Riemann Surfaces".  (They also have a nice discussion of slope-stability and the stratification.)
The top component of the stratification (those bundles where the stabilizer group is as small as possible) is the stack of (semi-)stable vector bundles.  If you take the coarse moduli space of this substack, you get the usual moduli space of stable bundles.
In summary:  If you drop the stability conditions, you get a lot more geometry with a similar flavor, and without the random bits of weirdness that crop up in the theory of moduli spaces.  (e.g., the stack always carries a universal bundle, you don't need the rank and the chern class to be coprime.)
OK, I'll stop evangelizing now.
Comment: Well, I'm actually quite fine with Artin stacks and such.  Here, I was more thinking about what happens when you take a specific unstable bundle, and what you can say about it, and also partly why (other than to get a GIT quotient) it might be bad.  However, thanks for doing a few things explicitly that I'd been meaning to work through.
Comment: Heh.  I did say I'd ramble, not that I'd answer your question.  But you might say that what's distinctive about unstable bundles is that their automorphism groups can get bigger.  (Caution: misleading when n=1)
Comment: " It's an increasing union of quotient stacks [A/G] of projective varieties by finite-dimensional groups." Shouldn't it be "quasi-projective varieties"? (Or maybe something strange is going on here.)
Comment: Yes, thanks!  In particular the statement I have in mind is the one gotten by considering trivializations of the bundles over formal neighborhoods of points.
Answer: Reider's proof of the Fujita conjecture that on a smooth surface, K+4A is very ample whenever A is ample, relies fundamentally on the Bogomolov instability theorem.  I.e. It is precisely the Bogomolov instability of the vector bundle produced by Serre's construction associated to a possible base point of a linear series K+L, under certain conditions on the chern classes, that allows one to conclude the result.  This technique seems to have played a major role in the study of linear series since that time.  See Igor Reider's paper in the Annals of Math, (1988), or the article of Lazarsfeld in volume 3 of the IAS Park City series, Complex algebraic geometry.
If you prefer to phrase it as bad behavior related to instability, I guess you could, since this shows that the presence of something bad, namely a base point, implies instability, which forces something else (the presence of certain curves though the base point on the surface) which if not bad, is at least rather special.  And this lets you classify all cases where the original bad behavior occurs.  So certain specific bundles can only be unstable in rather unusual ways.
Answer: Another reason behind the notion of stability is the "jumping phenomenon."  Namely, you can construct a family of vector bundles parametrized by the disk where all the fibers apart from the origin are mutually isomorphic, but not isomorphic to the fiber at the origin.  Concretely, you can realize this by scaling an extension class.  In the Atiyah-Bott-Kempf-Ness picture, this corresponds to non-closed orbits of the complex gauge group. When the base manifold has dimension greater than one, the pieces in the Harder-Narasimahan filtration may not be subbundles, so the limiting object is in general a torsion-free sheaf, and not necessarily a bundle.
Comment: this is a good example for why stability is related to good behavior in regard to moduli.  I.e. this shows the moduli space may not be separated at non stable bundles.

Unstable Vector Bundles


Are there examples of highly cited papers that very poorly written?

Question: We've had a little debate at work about whether a paper that presents good research, but that is at the same time very poorly written (either sloppy presentation, or not written in the native language of the authors), would nevertheless get a lot of citations. Are there good examples of such papers, specifically ones that present seminal work in some field, but that are very difficult to read because of the language or are riddled with errors?
Answer: I think Heidegger's Being and Time might fit this criteria. Though the philosopher's work was important to the field, he was criticized for the use of convoluted, imprecise language that managed to confuse other philosophers (Bertrand Russell being one such critic). In fact, the philosopher Paul Edwards published a collection of articles under the title Heidegger's Confusions in order to

rescue [Heidegger's] valuable ideas from the logical confusions in which they are embedded and from the willfully obscure and perverse language in which they are frequently expressed.

With regard to more recent (and research-oriented) writing: talk of the poor grammatical quality of academic journals has been around a while. Take a look at this quote from the Chronicle article "Bad Writing and Bad Thinking"

Many people—publishers of scholarly work, editors at higher-education publications, agents looking for academic authors capable of writing trade books—who think about the general quality of scholarly prose would admit that we're in a sorry state, and most would say there isn't much to do about it.

So, although an example other than Heidegger's writing doesn't come to mind, it doesn't seem you'll have to look very far.


How can I pass a fixed argument to a view within a panel?

Question: I have a view that will be repeated on many pages, and to not replicate many times, has two arguments. These arguments do not come from URL, are fixed. This view is inserted into a panel.
Is it possible? How?
Thanks!
Comment: Possible duplicate [link](http://drupal.stackexchange.com/questions/68473/adding-an-argument-to-a-view-programmaticly/68475#68475)
Answer: I'm making the assumption your on D7, with views 3, and have Views Content Panes running on your site (Views Content Panes comes with ctools).
So your gonna create your view as you normally would. When it's good and displaying as you want it to, add a display of a content pane (up near the top, under the display, hit the plus sign, select content pane). This will give you access to the "PANE SETTINGS," one of which is "Argument input." Click on this. If you have two contextual filters running on your view, there should be two drop down menus, one for each of your contextual filters.
Set both of these to "input on Pane Config." Now when your adding your views to your panels, your going to use the "View Panes," NOT the "views." Once you add your view pane, you should be presented with two text boxes for your contextual filters, you may set provide the arguments for those here.
Comment: That's correct, though if the arguments are in the panel URL, OP could also use that option for the argument input.


sources of water for martian terraformers

Question: The terraforming of Mars, assuming that the hurdle of establishing a magnetic field has already been jumped, now meets another problem: water. The planet has a pair of ice caps, but between them they haven't enough water to fill all of the Great Lakes, let alone cover 50% of the surface in water as the planet may once have been covered. So, other sources of water are necessary.
Cometary bombardment appeals, but I can't find any comets that orbit near mars. Phobos may contain large amounts of ice, so it could be used, but are there any other named bodies near mars that contain large amounts of ice?
Comment: Just look the way that K.S. Robinson did it in the Green Mars trilogy: Just claim there's humongous amounts of water ice underground (which with the current data, we cannot exclude).
Answer: No easy way to do it
Mars in unlikely to contain vast oceans of water in any discreet way. However, there's plenty of ice in the solar system. If you're serious about this terraformation thing, you'll need to put in the work to make it happen. You said there are no nearby comets. Well, orbits can be changed.
You'll find some sources of ice in the asteroid belt and much more in the outer solar system. Jupiter, Saturn, etc. Automated rockets/drones will need to be built and deployed en masse to millions of targets throughout Sol, adjusting the objects' paths to intersect Mars in the coming decades.
And if you're looking to fast-track things, and if you have torch drives or a vast beam power network, those rockets may need to push their target objects on non-Keplerian/brachistochronic trajectories.
Answer: Are you looking for a serious scientific discussion of how to terraform Mars? Or something that would work for a science fiction story?
If (b), the answer is simple: Make something up. Just blithely say that explorers found large quantities of ice or liquid water beneath the surface. Say that they found an asteroid made of ice and attached rockets to it to redirect its orbit to collide with Mars. Or say that scientists have invented some chemical process that quickly and efficiently turns some chemical in the Martian soil or atmosphere into water.
Answer: So, this is total spitballing on my part but was inspired by the OP having already solved the problem of mars having no magnetic field, relies heavily on that assumption and how it might work.
Mars has an abundance of carbon dioxide and carbon monoxide. Not much Hydrogen as it gets blow away from the thin atmosphere by the solar wind. Ironically the solar wind contains an abundance of hydrogen.
Step One: Shield Mars from the harmful radiation and solar wind, in the same process harvest hydrogen from the solar wind.
Step Two: split CO2 into C and O2 in the martian atmosphere. Sequester the carbon from recombining with the O2 buy combining it into carbon-silicate
Step Three: After oxidation of the atmosphere is complete begin catalyzation of collected hydrogen and oxygen into water.
Obviously this will require enormous amounts of energy over a quite a long time. I have only a vague idea of the density of hydrogen contained in the solar wind, nor its rate of flow and  how big of a collector needed. So how long this would take IDK. Your fault for not asking for hard science :D
Additional thoughts: Precisely yeeting the 4 largest asteroids (roughly 60% the total mass of the entire belot in just those 4 Ceres; Vesta, Pallas, and Hygiea) into Mars to add whatever water and their mass to Mars may speed the process. OR... perhaps Give mars a decent moon MIGHT have beneficial results as does Earth's Moon.
Mass drivers installed on Europa aimed at Mars could be an interesting delivery system.
Comment: What is carbon silicate?
Comment: @SeanOConnor https://en.m.wikipedia.org/wiki/Silicon_carbonate
Comment: https://space.stackexchange.com/a/45984/15771 has some numbers on the density issues. You would need an utterly gigantic collector to make this work. You would also need to brake the hydrogen by a couple hundred km/s, and there's nowhere near enough CO2 to make all the water you need for terraforming. Just go grab some comets.
Comment: @ChristopherJamesHuff the discussion seems to bolster this idea. Agree that the apparatus to collect that much H, would be ludicrously large perhaps the HxW of a planetary magnetic field. Which is what I proposed. In any case a magnetic field or something solving the problem being nessisary. Why not have it serve dual purpose.  And in the least case it could help maintain an established atmosphere.
Comment: ...it really doesn't. Mars has 0.28 times Earth's surface area. Scaling the water requirements with surface area, Mars needs about 4e16 t of hydrogen to match Earth. If you captured *all of the sun's solar wind* with 100% efficiency, it'd take about a thousand years to collect enough hydrogen. If you only caught what came within half an AU or so of Mars (a magnetic bubble that would reach Earth when the two planets pass each other), that goes up to about 40 thousand years. And the secondary purpose isn't really needed, once you've constructed an atmosphere it'll remain for millions of years.
Comment: And since Mars doesn't have nearly enough oxygen in its CO2, you'd need to crack it from the rocks in the crust. And you'd still need to get nitrogen somewhere, while you could get at least some from comets.
Answer: Make your own water.
Mars has plenty of mass.  People call it "Mars".  If you want water all you need to do it take that Mars stuff apart and put it back together as water.
Iron, for example.  Lots of that on Mars.  An atom of iron has 30 protons.  Bust them up.  Now you have 30 hydrogen atoms!  You can hook a couple of them to the oxygen that used to be with the iron and get a molecule of water.  Now you have 28.  You can make 2 oxygen atoms (8 protons each) and 4 more hydrogens and viola!  2 more molecules of water.  You have some protons and neutrons left over; save those for later.
"But but but but" you protest wetly.  "Busting up the iron atom takes a lot of energy!"  Short on energy, are you?  Perhaps Mars is too ambitious.  Maybe you can work on terraforming Kansas.
Answer: Instead of a few big rocks how about lots of little ones?
I'm imagining some kind of autonomous drone swarm. Details are up to you but a drone might look like this:
A small nuclear reactor for long-lasting power. Some kind of robotic arms/tools/etc. to interact with the rocks they encounter. A rocket engine. And some way to convert ice into Hydrolox for fuel.
A drone attaches to some rock. Extracts ice to replenish its fuel. Adjusts the rock's orbit so that it intersects with Mars in the next, say, 10 years. Then takes off for the next rock that needs adjusting.
If you've got a swarm of these moving around the solar system then you could accomplish a lot over the course of a decade.
Answer: Crash a moon into it
If your civilisation has advanced to the point where they are terraforming planets then you can do some pretty big things.
If you don't mind destroying everything on the surface in the process, there are several moons and other bodies in the solar system with enough water to cover the planet in one go.
Here's a helpful chart of the largest bodies of water in the solar system (based on current estimates). Mars has a volume of ~163 ZL so the top 3 would be closer to crashing Mars into another Mars. But hey if we're gonna be terraforming anyway maybe you want to make it a bit bigger.
Comment: you would also render he surface uninhabitable for millions of years just due to heating back to molten if you drop it all one once, plus al ot of it gets blown back out into space, better to do many smaller drops.


Can I say that my advisor acted in a bad faith?

Question: I submitted ten papers to my advisor based on her assignment within one year, approximately, every two or three weeks, I handed in one paper to the advisor.
Unfortunately, owing to my negligence, the eighth has plagiarism, the advisor kept silent, two weeks later, I submitted the ninth within the same problem, but advisor still did not contact me. Another two weeks, I emailed my tenth, also the last paper with plagiarism to advisor.
 After that, my advisor notified me to go to her office where she told me that my last three papers have plagiarism and she already filed a complaint against me to Faculty of Graduate Studies at University...  I was stunned on the spot.
    Please ask, could my advisor do in academic procedure( without telling the student ahead of time then directly made a report to Faculty of Graduate Studies?
Comment: Oh, please. Plagiarism is not "negligence". It is a deliberate act of deception. So you, the deceitful cheat, want to know if your _advisor_ acted in bad faith? You're a hypocrite as well as a cheat.
Comment: @MadJack I assume this is "paper" in the sense of "essay which will be graded" rather than "article to be submitted for publication".
Comment: Rules vary between institutions, and we don't know whether yours allows this; you'll have to consult its regulations.  Certainly it wouldn't be unusual for this to be allowed, or even required.
Comment: Even if you didn't commit plagiarism, working in a group where each student pumps out a paper every two weeks is going to be bad for your career. This is a screwed-up situation all around.
Comment: @DavidRicherby Ah yes, that would make more sense.
Comment: Did you know that you were plagiarizing in the 8th paper? Or you just come to the realization that you were plagiarizing after she told you?
Answer: I am sure you have been told that plagiarism is a punishable offense the moment you enrolled.  He/she is just following university procedure.
Comment: @peik Seriously, get over yourself. You cheated and you think the person who caught you has a malicious motive? You don't seem to have even the most basic understanding of what you've done.
Comment: I appreciate prompt comments from keen readers; the scenario I described is I am a Ph.D. student in History. My advisor assigned me to write a series of historiographic papers, but these papers are not marked, that is say, the grade of my qualified candidacy exam is completely based on my written test, no any connection with the previous written papers whereas the last three papers have plagiarism; in such a context, I felt that way my advisor dealt with has malicious motive.


What does "slicker than snot on a doorknob" mean?

Question: I have a friend from Mississippi and I've heard him use this expression sometimes: slicker than snot on a doorknob. What exactly does it mean? (I guess it's something positive but I'm not too sure myself.)
Comment: Note that "slick" also can mean impressive/clever, so this expression might be a follow up to to "Hey did you see the acrobats in the second half of the show?"
Answer: Doorknobs, generally being made of smooth materials such as brass or glass, are somewhat slippery.  Snot, also being made of smooth materials, is comparably slippery.
Combine the two and you have quite the traction-less situation.
This is a vivid metaphor known colloquially as a 'redneck expression', like colder than a witch's tit in a brass brassiere or hotter than two rats [redacted] in a wool sock.
For what it's worth, I have always heard it as slicker than snot on a **glass** doorknob.
Comment: It's likely, as tchrist notes below, that the original alliterative substance was bowdlerized to "snot".
Comment: I figured there'd be lots of alternatives, so I searched for just **colder than a** first. And was quite surprised to see that [for a while](http://books.google.com/ngrams/graph?content=colder+than+a+mackerel%2Ccolder+than+a+witch%27s+tit&year_start=1800&year_end=2000&corpus=0&smoothing=3) **colder than a mackerel** (which I've never heard before) was more common (in print, at least). Also surprised while leafing through the first search to see quite a few **colder than a banker's smile**.
Comment: Google Books has 114 hits for plain *"doorknob"* (plus 6 for *"door knob"*). It also has three for *"glass doorknob"*, a couple for *"bedpost"*, and a few one-off's like *"chamois skin"*, *"snow cone"*, *"mitten"*, etc. Whatever - it's only in the last decade that it's started to be used in reference to *literal slipperiness*. Almost every earlier reference involves metaphorical "slickness" in the sense of *superficially "polished, smooth", but actually sly, artful, shrewd*.
Comment: The ngram for 'colder than a witch's tit' is interesting.
Comment: Ooh, I like _colder than a banker's smile_.
Comment: Turns out they were duplicates of a single written instance, but I found some more on the Internet, and it's still interesting to note that they mostly predate the western world's current exceptionally negative attitude towards bankers. The world at large should take more notice of idiom-coiners - they're ahead of their time!
Comment: @cornbreadninja I think it also has to do with the fact that the doorknob turns adding more to the slippery mess then was already there!
Answer: I'm inclined to think this expression may be a coinage from Harlan Ellison (sci-fi writer hero of my youth, who moved on to become a successful Hollywood screenwriter). The earliest occurrence of slicker than snot I can find is from his 1972 The other glass teat: further essays of opinion on television. He writes of some particularly abysmal TV shows that they have vanished...

...with no moans of sadness, for they passed through our culture and prime time slicker than snot on a doorknob (or doo-doo through a colander, depending how vomitous you'll allow me to get)

Based on the fact that doo-doo through a colander occurs nowhere else in Google Books, it seems likely to me that Ellison created both expressions there and then, but only the former survived.
Ellison himself is pretty slick with words - among which I'm quite taken with his "The two most common elements in the universe are Hydrogen and stupidity."

As regards meaning, per Ellison's usage above, it's an alliterative conjunction of (pejorative) slickness with a situation whereby something exceptionally unpleasant turns out to be exactly where you can't avoid coming into contact with it (you have to turn the knob to use the door).
More recent usages often dispense with the "unpleasant" connotation, with the expression being used as a (sometimes even admiring) metaphorical reference to a smooth operator, or simply a literal reference to slipperiness (icy roads, pavements, etc.)
Comment: I Have No Mouth and I Must ELU
Comment: ... **shit** isn't normally associated with "slickness". It's usually **sticky**, and mostly it sticks to a **shovel** or a **blanket**.
Comment: It's not the colander version you should grope for, but *slicker than shit on a shingle*.
Comment: @tchrist: Maybe that's what they say in your neck of the woods, but in the entire Google Books corpus, the *only* hit for *"slicker than shit on a"* is a single instance of [slicker than shit on a Simonized floor](http://www.google.co.uk/search?q=%22slicker+than+shit+on+a%22&btnG=Search+Books&tbm=bks&tbo=1). You have to be careful not to globalise what you hear locally.
Comment: Even today you are much less likely to encounter coarse slang in print than you are in casual banter. That's another failing of the googlebot.
Comment: @tchrist: Yeah, yeah. But not even *one*? Not even on the *Internet*, let alone Google Books? You get *served shit on a shingle*, but it ain't slick.
Comment: The trigram ***slicker than shit*** is extremely frequent.   Try it: there's a googolplex of results.
So I disagree with your not-slick beef.
Comment: @tchrist: I think you just don't like to concede the smallest point. I didn't mean to imply nobody *ever* says *"slicker than shit"* in any construction. I simply said collocation with *"shingle"* isn't common enough to be recorded. And it remains the case that *"slicker than shit"* is 2-3 times less common than *"sticks like shit"*, both in GB and the Internet at large.
Answer: With regard to the earliest confirmed appearance of "snot on a doorknob" in print, I note the expression is mentioned at least as early as the 1960s, including one instance that notes it as having been collected by a folklorist in 1953.
From a footnote in Austin Fife, Folklore: Collected Articles of Austin E. Fife: 1939, 1941, 1960-1967; Book Reviews: 1947-1965 (1967) (also published in Western Folklore [July 1966]) [snippet view] :

As slick as snot on a doorknob (OCH).

Fife's exposure to the expression seems to have come from a conversation with Opal C. Howell, of Moab, Utah, on July 27, 1953, according to this note from the book (combined snippets):

More Similes from Moab, Utah.—The following similes were recorded at a single sitting from Mrs. Anne S. Chamberlain, 65, and her daughter, Mrs. Opal C. Howell, 25, both of Moab Utah, by Austin E. Fie and Alta S. Fife, July 27, 1953. (Fife Collection I 882, pp. 1–4.) The recital alternated between mother and daughter until one had exhausted the store for the moment; then the other would take over. The present alphabetical arrangement by adjective and verb does not show how preponderant the mother's repertory was, even though the initials ASC and OCH have been added to show respective authorship.

A decade later, Western Folklore, volumes 35–36 (1976[?]) lists an extended version of "snot on a doorknob" as a simile for slick [snippet view]:

as slick as greased hog snot on a doorknob (1F)

The same source cites the "slicker than" comparative form, as well:

slicker than snot on a doorknob

Other probable early instances of "snot on a doorknob" appear in nonviewable texts, including Southern Folklore Quarterly, volume 28 (1964), and Leon Harris, Only to God: The Extraordinary Life of Godfrey Lowell Cabot (1967).
One other interesting early instance appears in an unidentified, in Newsweek, volume 82, issues 19–27 (1973) [combined snippets]:

The rest of us suffered brain damage indeed under the salty orthodoxies of the Moral Life. Freakishly, Lee never paid "the price," whatever that is: all the right-blooded Ervins and correctitudinous the contrary, poor Little Old Lee got absolutely everything in life he ever wanted. Because, as my grandfather said, "he was slick as snot on a doorknob."

And from "Is Rio Hondo Slipping Down Hill?" in the [Whittier, California] El Paisano (May 20, 1975):

"The reason Rio is creeping down the hill," says Caskey, "is that the clay soil becomes wet from rain and from watering the lawns."
Caskey said the school is built on soil over bedrock, [W]hen the soil becomes wet, it can become "slicker than snot on a doorknob."

Collections of similes list numerous "slick as a" or "slicker than"comparisons, but do not include "snot on a doorknob" among them.
For example, Richard Thornton, An American Glossary (1962) notes that slick originated as a variant form of sleek in the sense of "smooth, neat, easy; also smoothly, quickly." Thornton notes multiple similes built on slick—"slick as an eel," "slick as oil," "slick as goose-grease," "slick as a candle," and "slick as a whistle"—but not "slick as snot."
Frank Wilstach, Dictionary of Similes (1924) lists "slick as a ribbon," ""slick as greased lightning," "slick as sin," "slick as a whistle," "slick as grease," "slick as a butterfly's wing," and "slick as soap grease"—but not "slick as snot on a doorknob [or elsewhere]."
Ellen Massey, Bittersweet Country (1978) doe list the expression, along with another vivid simile [snippet view]:

Slick as a wax snake on a marble floor.

Slick as snot on a doorknob.

Robert Hendrickson, The Facts on File Dictionary of American Regionalisms (2000) mentions "slick as a school-marm's leg" (from New England), "slicker'n a smelt" (also from New England), and "slick as a peeled onion" (from Appalachia), but no snot-related similes.

Conclusions
Although Harlan Ellison's use of the expression "slicker than snot on a doorknob" in The Other Glass Teat: Further Essays of Opinion on Television (1972) is one of the earliest published instances of the simile in that form, "slick as snot on a doorknob" is noted in two unrelated folklore glossaries from the 1960s, one of which cites its use by a speaker in Utah in 1953. The phrase thus seems likely to have originated in the U.S. South or West no later than the very early 1950s.
Nevertheless, growing up in southeast Texas in the 1960s, I never heard anyone use the expression. My impression is that it is not recognized and used as a standard simile in much of the United States, even today.
Comment: FWIW: I was born in Pennsylvania, and most of the English speakers who I've related to are Appalachian of some sort (N and S). "Slick as snot on a doorknob" seems perfectly natural to me, and I've heard it often.
Answer: To me, it means that your hand will come off of said doorknob VERY FAST!  Based on the idea that if you grab onto a doorknob that has something unknown on it, your first instinct is to let go.  But once you realize that said substance is SNOT, your entire mind and body will be completely consumed with the visceral commitmentment to remove your hand!!  Perhaps at speed approaching the speed of sound.
And anybody with a whit of imagination can relate, and will unconsciously wince at the thought of sticking their own hand on a similar doorknob.
Answer: The connotations of slick in US usage are broader than in British usage. In the USA, slick can mean both physically slippery ("Be careful! The roads are very slick this morning!") and metaphorically slippery ("His answer was too slick for her liking") or metaphorically polished ("She delivered a very slick presentation at the conference"); British usage does not generally imply physical slipperiness.
It is not apparent from the OP's question whether the referent is a person or a physical object.
For me, describing a person as slicker than snot on a doorknob strongly suggests that they are given to sophistry, equivocation, evasiveness or the deceitful manipulation of appearances; they are certainly not to be trusted.
A similarly described physical object (e.g. a road surface or knife handle) is extremely slippery and lacking in grippability, and may also be unpleasant to touch for either physical or psychological reasons.
It's a colourful expression, but a pretty vulgar one. In other words, it's ideal for teenagers who want to piss off their parents.
Comment: I disagree with your assertion that "British usage does not generally imply physical slipperiness" - it seems fairly common in British English to use 'slick' to describe, for example, an icy road in winter.
Comment: The quantifiable evidence is not on your side: if you use Google's Ngram viewer to compare the usage frequency for "The road was slick" for the 2009 American English corpus versus the 2009 British English corpus, you'll discover that it is recorded as having zero frequency in BrE. A similar result is found when you compare the frequency of the same term in the generic AmE and BrE corpuses.


My Bitcoin wallet is out of sync after connecting for the first time

Question: It's 4 years out of date. I have tried using a different network. Same thing. Don't know what to do but would appreciate help.
Comment: P.S. Please don't pad out your question. The minimum character limit is there for a reason: questions that are under it usually don't provide enough details, and have been asked before.
Answer: The official Bitcoin software has to download the details of every single address, transaction and confirmation block to be synchronised. If you've just installed it then it's going to take you 1-5 days to download that data depending on your Internet and computer speed (just leave it running on your computer).
There are other options to avoid this but as a rule of thumb it's more secure to use a "full client" such as the official software. Once it has sync'd every time you use it after that it will only need to sync the data since it last sync'd so is much, much quicker.


Are there any works discussing planetary bodies being forms of life?

Question: I'm searching for works or individuals that consider and discuss the idea of planetary bodies being considered stand alone living creatures, rather than objects either capable or incapable of supporting life.  Anyone familiar with something along those lines?
Answer: Look up Gaia hypothesis, James Lovelock, and Lynn Margulis.
Comment: Excellent, exactly what I was looking for, thanks!


Check pkg content in Solaris 10

Question: I using solaris 10 and i have a pkg files how can i list out the its contents?
Answer: A list of the (to be installed) files can be displayed using the pkgchk command:
pkgchk -d package.pkg -l

If the pkg file has contains more than one package, you will be prompted. e.g.
The following packages are available:
  1  JetRedHat     JET RedHat support
                   (sparc) 4.4
  2  SUNWjet       Sun JumpStart Enterprise Toolkit
                   (sparc,i386) 4.7

Select package(s) you wish to process (or 'all' to process

The pkgtrans command can change the entire package from datastream to file system fomat
if the -i option is not used. This can be helpful if you want to see the actions
 that occur after the package is installed onto a system.
e.g:
less SUNWjet/install/postinstall

Answer: Unfortunately the Solaris package management system doesn't make this easy.  You could try the following:
pkgtrans -i <pkgfile> spool

This will extract the pkginfo and pkgmap (list of files) files to /var/spool/pkg/package_name.  You could review them there.
Answer: I get the package content through the command below:
$ strings <your-package-name> | grep ^"1 "

Answer: You can run  for a spesific  package which  installed;
#pkgchk  -l <packagename>

Also  before  installing you can run and check  package content.
pkgchk -d  expect-5.45-sol10-x86-local   -l

And you can check  for a spesific  path.
pkgchk -lp /usr/local/bin/expect

Check  this  link  for  more details and  command  usage examples.

Check pkg content in Solaris 10


Anyconnect VPN whitelist physical devices

Question: My company uses Anyconnect VPN of Cisco, and any company PC device is required AD username/password to access the network. I'm thinking about the case when an employee copies the whole windows (copy the whole disk) and put on a non-company device. Is there a way to detect this case? If yes, how to configurate to fire an alarm or notification when a non-company device tried to access the network?
Answer: One could in theory use a computer's TPM to store a asymmetric key/certificate and use certificate authentication for the VPN.
Assuming there is no vulnerability in the TPM which allows the export of private key material, copying the Windows to a device which has not had it's TPM set up by the organization should be useless.
Everything else is fake-able by a sufficiently advanced adversary.


Question on the fill-in morphism in a triangulated category

Question: Let
$$
\begin{array}{rcl}
A&\to& B\\
\downarrow & &\downarrow\\
A'&\to& B'
\end{array}
$$
be a commutative diagram in a triangulated category. By the axioms of a triangulated category, this may be 'completed' to
$$
\begin{array}{rccccl}
A&\to& B&\to& C&\to\\
\downarrow & &\downarrow&&\downarrow\\
A'&\to& B'&\to& C'&\to
\end{array}
$$
where both rows are exact triangles. Let
$$
\begin{array}{rccccl}
A&\to& B&\to& \tilde C&\to\\
\downarrow & &\downarrow&&\downarrow\\
A'&\to& B'&\to& \tilde C'&\to
\end{array}
$$
be another 'completion' of the initial diagram such that both rows are exact triangles. One gets that $C\cong \tilde C$ and $C'\cong \tilde C'$. My question is: May these two isomorphism be chosen in a way that the diagram
$$
\begin{array}{rcl}
C&\overset{\cong}{\to}& \tilde C\\
\downarrow & &\downarrow\\
C'&\overset{\cong}{\to}& \tilde C'
\end{array}
$$
commutes?
Answer: Not in general.
For example, let the original commutative square be
$$\begin{array}{ccc}
X[-1]&\to&0\\
\downarrow & &\downarrow\\
0&\to&X
\end{array}$$
for any non-zero object $X$.
This can be completed to a diagram
$$\begin{array}{cccccccc}
X[-1]&\to& 0&\to& X&\to &X\\
\downarrow & &\downarrow&&\downarrow&&\downarrow\\
0&\to& X&\to& X&\to& 0
\end{array}$$
with a completely free choice of the vertical map $X\to X$.
Taking two different completions, where this map is zero in one and the identity in the other, gives an example where the answer to your question is "no".
Comment: Dear Jeremy Rickard, I am sorry but I don't understand your answer anymore: Isn't only the zero map $X\to X$ a correct completion of the diagram? The identity wouldn't make the diagram commute. Did I understand you correctly?
Comment: @jeffrey Sorry, you're quite right. I had the diagram the wrong way round. I think it will be correct when I edit.
Comment: @jeffrey I've edited, and I think it's correct now.


What's the difference between 开 and 举办 when used for the meaning "to hold an event"?

Question: What is the difference between 开 and 举办 in the following sentence?
They both mean "to hold". Can you use both for big events like 奥运会 or little events like 派对 or 聚会 ?

每年开两次运动会,一次是水上运动会,一次是田径运动会。除此以外,学校还举办圣诞和春节音乐会,和文化节等活动。
Answer: 开 has other meanings beside; 'to hold' (events)
举办 is a specific term for 'hosting' and 'organizing'. If an organization 举办 something, you expect it to be well organized.
开 is less formal than举办. E.g. 在我家开派对 is less formal than 在我家举办派对.
在我家开派对 can mean you casually call a few friends over to your house. Not much preparation is required

We say 开班会, not 举办班会 because 班会 is a regular event, no additional organizing is needed

We say 举办学生会选举, not 开学生会选举 because 学生会选举 is a formal event that needed to be organized

In short, 开 (to hold) is more general and casual; 举办 (to hold) is more specific and formal (officially hold and organize)
开 itself carries the meaning of 'hold', it doesn't need to be short for anything
Depend on the context, 开 can be short for:

开办 (open and operate/ open and run) e.g. 开(办)学校

召开 (call for and open) e.g. (召)开会议
Comment: Are both ok with big events like Olimpic games. Is there a difference in this case of big events¿
Comment: 日本上次开奥运会是在1964年 and 日本上次举办奥运会是在1964年 mean the same, (just 开 sounds more casual and 举办 sounds more formal) As you said, it is a huge event, using the formal term '举办' is more fitting.
Answer: 开 is short and casual version of 召开.  So, the reason why 开 is casual is because of that omitting in spoken.
Both 召开 and 举办 are formal, but they denotes different meanings.
召开 means convene or convoke. E. g.  convene a meeting.
举办 is understood as 举行(to hold or stage),经办(to handle).  So, 举办 involves planning, applying, preparing, documenting, organizing, etc besides hold the event per se.  E. g.  举办奥林匹克运动会 implies that they will do more work such as planning, preparing, organizing, etc to make sure the Olympics opened successfully. Well, 召开奥林匹克运动会 just simply means open the Olympics and doesn't imply anything else as 举办 does.
Answer: 开 - to open (informal)
召开 - to open(formal)
办 - to hold(informal)
举办 - to hold(formal)
There are general rules about formal and informal, big events and little events. However, it's still better to spend time remembering different collocations. These are my personal feeling about various collocations.
开运动会 √ authentic, colloquial expression
召开运动会 sounds a bit weird, 召开 relates more about meetings
办运动会 ok, but less frequently used than 开
举办运动会 √ authentic, formal expression

开派对 √ authentic, colloquial expression
召开派对 sounds a bit weird, 召开 is too formal for a party
办派对 we don't use it like this
举办派对 sounds a bit weird, 举办 is too formal for a party

开聚会 we don't use it like this
召开聚会 we don't use it like this
办聚会 √ authentic, colloquial expression
举办聚会 sounds a bit weird, 举办 is too formal for a party


Toilet Paper US 6,709,762 B1

Question: Has US 6,709,762 B1 expired or is it still active?
Can you provide the original paperwork for this patent?
Answer: If you examine the metadata for this patent on Google Patents, you'll see that it has a PCT Number PCT/JP2000/000585, indicating that the original application was filed in Japan, and that this is a PCT application (worldwide).
A PCT application has a search phase and a national phase, and the information regarding the application status in individual countries may be found in PatentScope (via WO 2000/045689 A1, the WIPO application).
You'll find the following National Phase information:
Australia                 07.08.2001  23251/00    Granted:   29.04.2004
China                     03.02.2000  00803377.3
European Patent Office    29.08.2001  2000902068  Published: 28.11.2001
                                                  Withdrawn: 27.01.2005
United States of America  02.08.2001  09890247

Note that the European application was withdrawn, so you need only need to determine the status of the US, Australian and Chinese applications. Although the patent was filed from a Japanese application (JP 11/27294), it appears that coverage was not sought in Japan during the national phase. I'm not familiar with Japan's patent system, so someone may need to correct me there.
On Google Patents, under Legal Events:
Date           Code   Event Description
Aug 29, 2007   FPAY   Fee payment
                      Year of fee payment: 4
Nov 7, 2011    REMI   Maintenance fee reminder mailed
Mar 23, 2012   LAPS   Lapse for failure to pay maintenance fees
May 15, 2012   FP     Expired due to failure to pay maintenance fee
                      Effective date: 20120323

So, the US patent has lapsed (effective March 23, 2012) due to a failure to pay the maintenance fee. I should note that the source of this information is originally USPTO Public Pair, then via IFI/Fairview Research, to Google Patents.
The information for the Australian patent grant is available via AusPat:
Vol/Iss  Publication date  Publication action                       Reason
20/36    2006-09-21        Patent Ceased                            Application Ceased
18/18    2004-05-13        Letters Patent Sealed - Standard Patents
18/1     2004-01-08        Applications Accepted
14/38    2000-10-26        Applications OPI

So the Australian patent grant ceased on September 21, 2006.
For completeness, I would provide the status of the Chinese patent, but the SIPO application search is currently inaccessible for some reason.
Comment: The original Japanese application H11-027294 (from which priority is claimed by the PCT) was granted as JP 3352421 B on 20 September 2002. However, I don't know of any good way to check if the renewal fees have been paid since then.
Comment: @Ex-examiner Thank you for providing the additional information on the Japanese Patent. Where did you find it?
Comment: It's from the Japanese version of the JPO's [J-PlatPat online register](https://www.j-platpat.inpit.go.jp/web/all/top/BTmTopPage). For some reason, the English version seems to hide the status information of Japanese patents.
Comment: @vallismortis  Why do you refer to this as an application when it is a granted US patent?
Comment: @EricShain That was a mistake. I revised the answer to make a clearer distinction between the application and the patent.
Comment: @vallismortis  You still refer to it as an application in the first sentence of your answer. It would be great if you fixed that.
Comment: @EricShain Done.

Toilet Paper US 6,709,762 B1


Status messages with AJAX

Question: I'm making an AJAX call in drupal 7 via the standard AJAX Framework. My  problem is that when a status message is set by the AJAX callback, it is simply lost (or displayed at the next reload of the page). How can I display the status messages right after the AJAX callback has finished running, without reloading the page? Is there a module for that?
Answer: You can render the status messages and send them as anohter AJAX command.
For example:
<code>$commands = array();

// Add other commands

$commands[] = ajax_command_prepend('div#ajax-status-messages-wrapper', theme('status_messages'));

return array('#type' => 'ajax', '#commands' => $commands);
</code>
At least this is the way I solved this problem when I faced it.
Comment: You Are A Saviour!!! :D Thankyou so so much.
Comment: What is the use of theme('status_messages') in there?
Comment: @Bebang Bakikang render the status messages, returning HTML code with the current status messages.
Answer: For Drupal 8 it's
<code>$response = new AjaxResponse();
$status_messages = array('#type' => 'status_messages');
$messages = \Drupal::service('renderer')->renderRoot($status_messages);
if (!empty($messages)) {
  $response->addCommand(new PrependCommand('.your_selector', $messages));
}

return $response;
</code>
Answer: For Drupal 8 form with AJAX, answer by Tim Bozeman worked, but messages were showed up with no styling. This is what worked for me:
<code>$response = new AjaxResponse();
drupal_set_message($action);
$form['messages']['status'] = [
  '#type' => 'status_messages',
];
$response->addCommand(new InsertCommand(null, $form['messages']));

return $response;
</code>
Answer: for me
<code>$commands[] = ajax_command_remove('div.messages');
$commands[] = ajax_command_after('#main-content', theme('status_messages'));
</code>
worked. where #main-content is standard, and maybe needs to be customized for your theme's acutal messages position. (maybe you have to change the second method to ajax_command_append() or another)
Answer: I had this originally:
<code>\Drupal::messenger()->addMessage($this->t('Form Submitted Successfully'), 'status', TRUE);
$allMessages = \Drupal::messenger()->all();
$html = \Drupal::service('renderer')->renderRoot($allMessages);
$response->addCommand(new AfterCommand('div[data-drupal-messages-fallback]', $html));
</code>
But $html was always "". After reading answer from Tim, I added this:
<code>$allMessages['#type'] = 'status_messages';
</code>
after retrieving all the messages.. and it worked. Odd that ->all() wouldn't include that.
Answer: it's now much more easier :
<code>$response = new AjaxResponse();
$response->addCommand(new MessageCommand('Example of status message.'));
</code>
Get all information on this article: https://www.drupal.org/node/3086403
Answer: If you're here because in Drupal 8 / 9 you're trying to clear validation error messages upon successful form submission, here's what worked for me (with thanks to rémy for the Drupal 7 inspiration):
<code>// Remove any validation errors from previous submission.
$response = new AjaxResponse();
$selector = '.messages--error';
$response->addCommand(new RemoveCommand($selector));

return $response;
</code>

Status messages with AJAX


How to cut threads on 2" PVC pipe?

Question: I have some sections of 2" PVC and some Tee fittings that I need to join.  On the Tee fittings, the main line is threaded and the outlets are smooth.  How can I cut the threads in the straight sections to join with the threaded main line?
Comment: Why do you want to thread the PVC rather than gluing on a 75-cent slip-thread adapter?
Comment: I agree with @MatthewPK - PVC SHOULD NOT BE THREADED! It is to soft. It MUST be glued/clamped. If you are joining PVC to METAL(Copper) use the appropriate adapter. Ring clamp on one side and thread on the other. Costs a few bux but lasts forever!
Comment: Fishing pole would be a good application.
Answer: I see no reason why you should cut threads on a PVC pipe. It seems to me that this would be unnecessarily difficult and would weaken the pipe.
You should, instead, get a slip to thread adapter and glue it onto the pipe to thread it wherever you like. Any big-box hardware store or irrigation department should be able to provide this adapter.
Edit:
Here is a link to such an adapter for $1.56at big orange hardware store. :
https://www.homedepot.com/p/Charlotte-Pipe-2-in-PVC-Sch-40-MPT-x-S-Male-Adapter-PVC-02109-1600HD/203825431
Comment: Or replace the T with a non-threaded version.
Comment: Heh, you don't. PVC isn't thick enough or the proper material to be threaded. As is noted, there are glue on fittings specifically for this so don't go making up a kludge that has a high chance of failure.
Answer: Threaded fittings on PVC are intended to connect to existing, threaded NON-PVC connectors, such as galvanized pipe or fittings.
When connecting PVC to PVC it should all be glue joints without threads. You have the wrong type of fitting. Fittings are very cheap, much cheaper than adapters.
Answer: Need to thread PVC?  Use schedule 80.

Schedule 40 PVC pipe is for socket fittings (slip glue) only; threading is not a recommended practice.
Schedule 80 PVC pipe can be threaded.

Cite ~~>  http://www.usplastic.com/catalog/item.aspx?itemid=23979
Comment: Doesn't answer the question of **how** to cut the threads.
Answer: The thing to look for is a threaded adapter. I searched at my favorite big-box store's web site for both

PVC adapter
PVC copper adapter

Here is one that is PVC to PVC threads. You glue this one onto the unthreaded PVC, then screw it into the part that's threaded:
Images supplied by lowes.com. No endorsement intended or implied.
and here is one that is PVC to copper. This one is just a push-fit on the unthreaded PVC before screwing into the threaded end:

I didn't find one for 2" pipe, but if your local big-box doesn't have one, I'm sure any reasonably stocked plumbing supply store will have one. They would also know exactly what to get you if you simply asked for "something to connect PVC to a threaded copper pipe".
Answer: Simple, if expensive.
Use schedule 80 (or heavier) PVC pipe (only.)
Use a pipe thread die and diestock to cut threads, or set up an appropriate lathe with appropriate cutters running at appropriate angles to cut the threads. The die is generally a better choice unless you already own the lathe, know how to cut threads on it (even if they are angled threads) and have sticker shock from the cost of pipe dies but still want to thread the pipe rather than gluing on adapter fittings.
"Simple and cheap" buy and glue on adapter fittings.
This one is from "Supply house .com" is schedule 40 and costs under a buck at the time of writing - but thats not an endorsement, just an example

Better, simple, and cheap - buy Tees intended for glue on all three ports, no adapters needed.
Here's a schedule 40 2" all - glue Tee, and it's under $2. Same source for the picture, same lack of endorsement. Since you'd need two adapters for each Tee, probably a hair cheaper to just get the right Tees for all-glued threadless connections. Certainly less fuss to assemble leak-free, unless there's an unstated in the question need to disassemble by unscrewing.
Answer: You need a threading wrench (example that may or may not meet your specifications), a clamp, and schedule 80 PVC (I suggest schedule 120 though).
Clamp pvc at 90 degree angle and slowly start threading.   You have to keep perpendicular pressure on the wrench so that the threads width is consistent.   I took 5-6 practice runs before mine were acceptable.   The project I did was for a water pump output for a boat that had to be set up on dock.
I am not really sure why you wouldn't be a threaded piece and just join that with an adapter - which is probably more secure than a self-threaded connection.

How to cut threads on 2" PVC pipe?


When does a mac laptop startup automatically after a power failure?

Question: I'm trying to get the hang of this.  I notice that sometimes when I plug the charger the macbook boots automatically, other times it doesn't.  I know in desktop macs this is determined by a setting in Energy preferences, but not sure when this is supposed to happen with macbooks. Does it change with the model? It's good to know this for troubleshooting.  Any insights would be much appreciated.
Comment: Each model has different capabilities, so a Wikipedia list seems more practical than asking lots of people their experience. Is there one model you have in mind or does this need to be vague / survey for your needs?
Answer: Regardless of of the Mac model, the power settings determine if it will boot upon power failure.  If this option isn't set, it won't boot.
Comment: but macbooks don't have this setting if I'm right?  that's what I'm querying about.
Answer: It appears that this feature is controlled by a parameter in the Mac's NVRAM (non-volatile RAM, which contains various parameters used during the startup process). The parameter in question is AutoBoot, which controls whether the MacBook will automatically boot when the lid is opened or power is connected (note that there appears to be no way to separate these settings—if you disable boot-on-power, you also disable boot-on-lid-open). The %00 value for this parameter disables automatic boot, and %03 re-enables it. These values can be changed using the nvram command-line tool.
So, to disable automatic booting when power is connected, run the following command in the Terminal application (found in /Applications/Utilities/Terminal.app) by copy-pasting it into the Terminal, then pressing return. Note that this must be run by an administrator account.
sudo nvram AutoBoot=%00

You'll then see a prompt that looks like this:

Type your password, then press return. Nothing will appear on the screen as you are typing; this is normal.
To revert the changes (i.e., to restore the automatic booting behavior), execute the following command (once again as an administrator):
sudo nvram AutoBoot=%03

After entering your password (if prompted), the setting will be reset to the default.
To view the current values of the data in NVRAM, run the command nvram -p in Terminal. Look for the key on the right-hand side called AutoBoot. If this is set to %03, the laptop will automatically boot after a power failure (i.e., when re-connected to AC power); if AutoBoot set to %00, it won't.
Note that NVRAM values change from time to time, so this may not be applicable in the future. Moreover, if modification of these values causes further issues, you can reset your NVRAM to its factory state by following this process.
Here's an article with more information about the NVRAM parameters on the 2016 MacBook Pro.
Comment: with you folks out there there's no more need for teachers, Thanks!.  Also, I knew more or less of this autoboot in newer macs, I was interested mostly on 2015 and before mac laptops. By what I could test last week, these will always boot if you plug the magsafe after having disconnected magsafe and battery connector, so there's no need to use the power-on pads on the logic board to start the mac.
Answer: problem solved. My macbook pro early 2011, 13 inches; for two months it was turned off when the magsafe was disconnected, and when connected it was restarted.
Well, it occurred to me to clean the logic card, so I disarmed my macbook and wiped all the dust and lint accumulated for 9 years with a soft and static free-brush while having the logic board properly grounded on a static safe mat / grounded to earth to protect from static buildup.
After this, for two days I was using my macbook always connected to electricity, but then I disconnected it and now it works normally, with the battery charge. It works normal since I cleaned it thoroughly.
To summarize, heat buildup can cause this and a deep repair where you remove the logic board and clean out the case can help.


Was the Cold Steel Reign GM's guide ever published?

Question: Does anyone know if Mad Hermit Games ever published the Cold Steel Reign GM's guide?  If not, does anyone know of any source books/material that they published?  I liked the world background, just was disappointed that the player guide is just a large set of rules...
Answer: Looks like the answer is no.
Back in June, they were working on making the GM's guide available online, but since then their website has disappeared, and they haven't updated their Facebook status in all that time.  See for yourself at their Facebook page.
There's a GM screen for Cold Steel Reign available at Amazon, so at least something GM-oriented is available, not that it's much consolation.
I'm not optimistic that we'll see a GM's guide for this game any time soon.
Answer: I know this is an old question but thought I'd post an answer anyway...
Mad Hermit Games did actually release a GM's guide and a sourcebook, called the Dakota Territories, for CSR as PDF's which you bought and downloaded via their website. I can't remember exactly when I bought them, I think it was towards the begininng of last year but I can't be sure.
The GM's guide, at the time that I purchased it, was split into 10 pdf files (one file for each chapter) and is around 450-500 pages in length.
The sourcebook is a 41 page pdf detailing the Dakota Territories - includes geography of the region, the Barons of the region, encounter tables, usual sort of sourcebook stuff really.
I just thought I'd let people know that there is material out there, just might be tricky finding it!
Comment: Thanks, that is really helpful indeed.  Do you have any links to official sources of the PDFs? *By official, I mean where you can purchase/download it legally, no warez site advertising is allowed here.*
Comment: I don't unfortunately, the only links I had were on their website.
Answer: The short answer is sadly, "No, I don't think the GM Guide for CSR will ever be released to the public nor will any other source material aside from the Player's Guide and the GM Screen which were released years ago."  For detailed evidence supporting this conclusion please read on.
Long long ago at Origins in Columbus Ohio I played CSR with its creator, Patrick Ellison, and was so impressed by the concept that I immediately bought the Player's Guide and pre-ordered for a serious chunk of change the "soon to be released" Gamemaster's Guide.  Once I arrived home I immediately became active on their website forum and joined with the many who had given their money in excitedly taking part in any discussion on the game and its development.  Months passed and the updates from Patrick Ellison assuring us that though significantly delayed the guide would be forthcoming became more and more seldom.  Finally after months of no message at all from Patrick the site disappeared along with all of our money.
I personally emailed Ellison several times saying that I would be fine with him keeping my money if he would send me a PDF of whatever work he has completed on the GM Guide.  No response.  CSR has since been my bitterest disappointment and resentment in gaming.
Comment: I think this answer could be edited some but I think it's on topic for the question - it says no, with details.  Dissent, you might consider ramping back the off topic part.
Comment: Welcome to RPG.SE! I see you are seemingly new to Stackexchange. In that case have a look at our [FAQ]. I don't personally see this as much of an answer to this question. There is a lot of context and not much content. If you'd like to edit this into more of an answer feel free to ping me to remove the down vote.
Answer: I also purchased the GM guide through the website although unfortunately it seems as though Patrick has taken it down again.  If you're interested try posting on any of the Facebook pages in an effort to stir Patrick into bringing things online again. I know he was also working on the Bestiary and an additional Character Cats book. I don't know if he's finished these yet.
Answer: I know this is a very old question, but I never stumbled on this site until just now. There is a pdf of the DM Guide and also the Dakota Territories supplement. These will not be released in a print version. However, you can post a request for them on the official Facebook page. If you send a request with your email address and which, or both, books you would like, I can send you a download link for free.
Comment: Are you associated with Mad Hermit Games and/or Cold Steel Reign? If so, you should include that in your answer—both because it will make your answer more authoritative, and because we generally prefer answers to disclose relationships with products under discussion.
Comment: First, I am not infected with facebook so that is of limited use. Second, unless you are officially affiliated, then a "free" copy would breach stack rules.


Yinwei or Yinvei? 因为

Question: I hear some people say 因为 as "yinwei", but also some say it sound like "yinvei". I'm not sure why there is a difference in pronunciation.
Comment: To be clear, no /v/ exists in the pronunciation in Putonghua. However this is acceptable.
Comment: You should notice that there's a thing called accent, which doesn't only occurs in foreigners.
Answer: /v/ is not an initial found in MSM.

The initial /v/, though, is often found in Northern Mandarin and its branches. In fact, it can still be found, even, in distant branches like Sichuanese.
If you ever saw the 马蜂窝 commercial that aired, ever single night, during the World Cup, you'd certainly notice that 唐僧's "为" is very /v/'d.
You can also refer to the paper The geographic distribution rules and reasons of zero initial "w" pronounced as "v" in Mandarin  by Wang Fan. The abstract for the paper goes into some detail in English:

Abstract:
It  is  universal  to  pronounce  zero  initial  "w"  as  "v"  in Mandarin. Researches  show  that  38%  of  the  people with northern dialect do so with 10% in other dialect districts. When analyzing its features and reasons, we find that the dental fricative sound "v" is indeed a variant of the semi-vowel "w". Its coming into being is affected by the variation of the  mouth  in  different  phonemes.  It  is  also  related  to  individual  pronunciation  habits  and  the  instability  of  the  pronunciation.  The  universal  "v"  pronunciation  in  northern  dialect  district  is  caused  by  the  stronger  movement  of  the mouth and the face in pronouncing than that in other dialect districts.

The 为 in 因为 should be pronounced wei if you're going for "standard" Mandarin. But, if you want to make yourself sound more Northernized you can also opt for the v.
Comment: The characters 维 and 为 both reads **wei** in Mandarin, but 维 reads as **vei** in our Xi'an dialect.
Answer: There is no labiodental fricative [v], including in northerners' pronunciation. What you're hearing is a labiodental approximant [ʋ], which is sort of halfway between [w] and [v]. This is a variant pronunciation and phonemically equivalent to [w].
Because they are phonemically equivalent, both [w] and [ʋ] are represented by pinyin ⟨w⟩, rather than ⟨v⟩ or anything else.
The paper cited by the accepted answer looks pretty questionable to me, given that it doesn't make any distinction between labiodental fricative and labiodental approximant. In addition, the translation of 普遍 as "universal" in the abstract is wrong, because pronunciation of [w] with some dentalization is not universal, but rather a variant pronunciation that (by the paper's own conclusions) is in the minority.
Answer: According to Mandarin, yinwei, but you may pronounce as yinvei, it is just another variant of pronunciation of the word.
Comment: Hokkien, Cantonese, Hakka all say it with a "W"
Comment: @WayneCheah, oh, man, Cantonese is not mandarin.
Answer: 因为 is always pronounced as /Yīn wèi/
/yin vei/ sounds like a foreigner's mispronunciation of the words
there is no /vei/ sound in Mandarin pinyin (I searched all 4 tones)
Comment: It really _doesn't_ sound like a "foreigner's mispronunciation"--it sounds like a Northerner's mispronunciation! I've had professors at 复旦 who talk this way (who I presume were from the north).
Comment: It's very common among speakers in the north who otherwise have perfectly standard Mandarin, including teachers.

Yinwei or Yinvei? 因为


SharePoint 2013 list, how to add an "item deletion" button?

Question: can anybody help me on how to add a button or an icon to a SharePoint 2013 list, so that, when one or more items in the list are selected and click on the "deletion" button, the selected items will be getting deleted. I think this can only be achieved by adding a JavaScript code, but i have no idea how. Your help will greatly be appreciated.
Answer: Option A - The SP2013/16 way
Use the WYSIWYG Cisar Chrome Extension to write CSR-Client Side Rendering javascript to:

add a button
grab the ID
delete the Item with JSOM or REST code

Option B - using (unsupported) HTML/JS in a Calculated Column

Read and understand http://www.viewmaster365.com/#/How
Follow the steps: http://www.viewmaster365.com/#/Create/ActionDelete
Comment: Hello Danny, thanks for your excellent help .... but it looks to me that there are two problems relating to the solution(Option B): a. after having clicked on the "delete" button, the whole item is getting red but will not disappear until the page is reloaded ... is there a way to remove the item immediately? b. it looks like that the "deleted" item is actually hidden in the current view, but if you export the list to an Excel, it is still in the list, right? can we do a real "deletion"? thanks again


Java MANIFEST.MF long lines tolerant parser

Question: Does anyone know of a MANIFEST.MF parser library which tolerates long lines over the 72 character limit? I would also need a serialization back to file.
Comment: I'd suggest writing a simple preprocessor which fixes invalid files, then you can use any parser.
Answer: I could not found any library that would allow me to serialize overlong lines. But at least I found that Apache Ant's Manifest class can read the overlong lines. The parser is at https://gitbox.apache.org/repos/asf?p=ant.git;a=blob;f=src/main/org/apache/tools/ant/taskdefs/Manifest.java;h=6417a8da21b092a813fd05d34a8696cb4335c08e;hb=HEAD


Make Trashcan Carla friendly again using commands

Question: Is there a way to make Trashcan Carla friendly again after you rob her? I tried things like disable and markfordelete but it didn't work.
Answer: It doesn't work because it's actually a hidden quest that you "completed".
Before you do any of this, do a full save, not a quick save. Since this is a "vanilla" quest (part of the base game), futzing around with it can sometimes have unintended bad consequences.
The quest id we're targetting is "caravanbase". You can see the stages by running the command ShowQuestStages caravanbase. (sqs is shorthand for ShowQuestStages if you find yourself doing this a lot.) The quest can be reset entirely using the resetquest caravanbase command.
So:
sqs caravanbase
resetquest caravanbase

My current playthrough is in survival so I can't verify, but the above is from my notes from a previous playthrough when I did the same thing and regretted it.
Some googling brought up this reddit thread which has some additional commands if the above doesn't work.
However I've followed this set of commands in several playthroughs and they've always worked a charm. I can't say how mods might affect this, though -- I don't play with mods.
Comment: Although this (and some other commands from the reddit thread) solve the "robbery" issue, now I can't see any dialog option. She just says "Hay, want to trade?" (something along those lines) and sits there. Since this might be because of mods etc, I'll mark this as the accepted answer.
Comment: Oh -- that's odd. Yeah I've never played modded F4, so that's possibly it. Does she trade with you, at least?
Comment: Nope, she simple says her lines and nothing happens. No dialog/trade prompt. I thought it might have been the XDI mod but disabling didn't fix it. Oh well, no big deal.


Why is reduced echelon form of a matrix always the identity matrix

Question: If $A$ is $3\times3$ matrix with linearly independent columns, then why is the reduced echelon form the identity matrix?
Comment: My professor posted this question for our exam review.
Comment: Duplicate of http://math.stackexchange.com/questions/977819/why-is-the-reduced-echelon-form-of-a-set-of-independent-vectors-the-identity-ma
Comment: While this is technically a duplicate, I don't think it should necessarily be marked as such. It is quite possible that the OP doesn't realise that having independent columns means that necessarily the rows are independent - others may not also. (Of course, it is the case, but this does actually take some thinking.) Alternatively, could be marked as such and a note put on the other question...
Answer: If the columns of the matrix are linearly independent this means that they span the vector space. We can think of the matrix as a linear transformation T: since the dimImT = dimV, we have that the transformation is onto and injective, thus invertible.
Now, the identity matrix is also a representation of a linear transformation and we can think about it as a vector space with dimension equal to that of T. Thus we have an isomorphism between the identity matrix and the original matrix.
Lastly, define a series of row operations which act on either matrix to achieve the second. These operations are linear and thus do not change the image of the transformations.
Hope this helps,
Answer: Because of two things:

Row operations preserve column dependencies and independencies in matrices.

E.g. if $A=[\mathbf{a}_1,\mathbf{a}_2,\mathbf{a}_3]$ has the column dependency $\mathbf{a}_1+2\mathbf{a}_2=\mathbf{a}_3$, and $B=[\mathbf{b}_1,\mathbf{b}_2,\mathbf{b}_3]$ is row-equivalent to $A$, then $\mathbf{b}_1+2\mathbf{b}_2=\mathbf{b}_3$ also.
To prove this, we just check it holds each of the row operations.

The identity matrix is the only matrix in reduced row echelon form with linearly independent columns.

In any other reduced row echelon form matrix, any non-zero column without a leading entry can be written as a linear combination of other columns (a zero column is linearly dependent in itself).
Answer: Method 1
Since all the columns are independent, the determinant is non-zero. So we see that there must be at least one non-zero entry. Swap rows and columns so that this is in the top left, then divide the entire row (or column) by this value. This gives a 1 in the top left. We can then 'clear' the top row and left column by standard row/column operations (if entry (1,2) is 3, then subtract 3 times the first column from the second column, etc).
We know that swapping rows/columns only changes the determinant by a sign, and dividing through by a (finite!) number changes the absolute value, but not whether it is zero or not. So the determinant of the 2x2 matrix in the bottom right must be non-zero (as the new determinant is 1 times this). So we can do the same for this, observing that any row/column operations have no effect on the first row/column, since you're adding/subtracting (multiples of) 0.
So do this and we get the identity. :)
Similarly, for any $n$x$n$ matrix with independent rows (non-zero determinant), we have that the reduced echelon form is the identity. We argue this by induction: do it once as explained above, then since the determinant remains non-zero, apply the inductive argument.

Method 2
We know that the top left of a reduced echelon form is always the identity matrix, then always zeros. That is, we have the form
$$\left( \begin{matrix}
I & 0 \\
0 & 0
\end{matrix} \right).$$
We know that the size of the matrix $I$ (that is, 'dimension': number of columns/rows) is the rank of the matrix (and the number of remaining rows/columns is the dimension of the kernel - this is guaranteed by the rank-nullity theorem). But, since we have independent columns, we know that the kernel is trivial, ie just the element $0$, and the image/range is full, ie given any $y$ there exists $u$ such that $Au = y$, where $A$ is the original matrix ($A$ is invertible, so $x = A^{-1}y$). Thus $I$ has 3 rows/columns (maximal) and the final $0$ has dimension 0 (just the point $0$). Thus the reduced echelon form is just $I$.

If anything isn't clear, just give me a shout and I'll elaborate!
If this has helped, then please remember to upvote and/or accept!