We are using MapInfo in our organisation to maintain corporate GIS datasets (in TAB files). We've come to realise the importance of maintaining a metadata file for our GIS layers. Are there any free/open-source metadata managers out there that can help us achieve the desired objectives?

I am looking for a free open source ISO metadata editor for the development of an enterprise database.    It will mostly be used for documenting shapefiles and GeoTIFFs.   Hoping that it will be an intuitive software since a range of skill levels will be working with it.  Any suggestions?


i am unable to set up my canon lbp2900 printer on ubuntu12.04 64 bit i aliened the 64 bit rpm drivers and then installed the drivers (version 2.40) and followed the procedure in the canon guide ( however i changed fifo path to //localhost:59787 (somebody suggested) instead of 59687 (as suggested by canon guide) )  intially i got the message pstocapt failed .. the drivers had put the pstocapt and backend/ccp in the lib64 directory instead of the lib directory ... i copied that to the aproprite directory under lib  but still i get the error "ccp send_data error exit " i also tried with fifo path //localhost:59687  i also tried the Radu script but the drivers the script uses are version 1.90 and has conflicting packages

I am trying very hard to install Canon LBP2900b Printer in Ubuntu 13.10.  I have searched and googled a lot for the solution over fortnight but none of the site / link gave me the simple solution for me. How can accomplish my goal?


I know that when an object has no references, the garbage collector frees the memory. But I have a doubt.  I have a class that is represented by a tree:  class MyNode {     string Name;     List<MyNode> Descendants;     MyNode Parent; }   When I create a node that has descendants, I have the reference to the node and also the son has a reference to the node in the Parent property. Also, the node has a reference to the descendant in the list of descendants.  So an example.  Node myNode = new Node(); Node myDescendant = new Node(); myNode.Descendants.Add(myDescendant); myDescendant.Parent = myNode;   I can delete the reference to myNode setting it to null. However, the object is still referenced because myDescendant references to it in the Parent property. The myDescendant object is not recollected because is referenced in the descendants list of the node object.  So it seems that there are a cycle that avoid the node recollection. Is this true? Perhaps I need to set to null all the properties in the node and in the descendants and clear the list of descendants?  Thanks so much.

I'm trying to run down a memory leak in a windows forms application.  I'm looking now at a form which contains several embedded forms.  What worries me is that the child forms, in their constructor, take a reference to the parent form, and keep it in a private member field.  So it seems to me that come garbage-collection time:  Parent has a reference to the child form, via the controls collection (child form is embedded there).  Child form is not GC'd.  Child form has a reference to the parent form, via the private member field.  Parent form is not GC'd.   Is this an accurate understanding of how the garbage collector will evaluate the situation?  Any way to 'prove' it for testing purposes?


How do I wire a 2way 2light system. On the upstairs landing I want to switch 2 lights on and off at each end of the corridor.

My "power in"  box has its black/white and ground and also the three wire cable( black /white /red and ground)  and also the first light wires ( black/white).    how do I wire this.  It is going to two lights--  the first light is pretty simple - just black and white-- ends at fixture--- also the cable feeding light # 2  and then moving on to the second three way box. It seems I have an extra black wire in the initial "power in" box...  Do I hook the black power in with the black cable and let the current circulate?   or attach the power in to the dark screw.  and then what do I do with the other two black wires? black cable to black first light?    white cable to single light screw side,( as traveler) and red to double screw light screw side?   I have seen a couple photos and nothing is crystal clear.


This is the code: select security,max(dte),close,ask,bid,mid from k$prices where to_char(dte,'MON-YYYY') = 'JAN-2021' group by security,close,ask,bid,mid,dte order by security,dte desc  Below is the result: I only want to get 2 rows, which has the highest date for each security (436 January 5 and 448 January 29) but because the values of the fields are different, all rows are still being shown. Please help me. Thanks

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


According to what I was reading, the formation of an event horizon appears if the mass becomes compact enough. Unfortunately, due to time dilation the time for mass to fall into the event horizon becomes infinite, so that nothing can cross the horizon within in the life time of the universe. Another thing is, that energy loss because of hypothetical hawking radiation would take place in finite time. Consequently, there must be something wrong with these models. Which means, there is neither a singularity nor a real event horizon existing out there.

The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-observer.  If this is the case how can anything ever fall into a black hole.  In my thought experiment I am in a spaceship with a powerful telescope that can detect light at a wide range of wavelengths.  I have it focused on the black hole and watch as a large rock approaches the event horizon.  Am I correct in saying that from my far-away-position the rock would freeze outside the event horizon and would never pass it? If this is the case how can a black hole ever consume any material, let alone grow to millions of solar masses.  If I was able to train the telescope onto the black hole for millions of years would I still see the rock at the edge of the event horizon?  I am getting ready for the response of the object would slowly fade.  Why would it slowly fade and if it would how long would this fading take?  If it is going to red shift at some point would the red shifting not slow down to a standstill? This question has been bugging me for years!  OK - just an edit based on responses so far.  Again, please keep thinking from an observers point of view.  If observers see objects slowly fade and slowly disappear as they approach the event horizon would that mean that over time the event horizon would be "lumpy" with objects invisible, but not passed through?  We should be able to detect the "lumpiness" should we not through?


Let G be a domain,  and let $f_1 \ldots f_n$ analytics in G such that $$ h = |f_1|^2 + \ldots + |f_n|^2$$ is constant  prove that every $f_i$ is also constant in G  the question has a hint to calculate the laplacian  I'm not sure how to do it,   I tried to do: $|f_i|^2 = f\bar{f} \to (|f_i|^2)'' = f_i''\bar{f_i} + 2f_i'\bar{f_i}' + f_i\bar{f_i}'' = f_i''\bar{f_i} + |f_i'|^2 + f_i\bar{f_i}''$  I think I should somehow get rid of the $f_i''\bar{f_i} +  f_i\bar{f_i}''$ part  and I would get something of the form $$|f_1'|^2 + \ldots + |f_n'|^2 = 0 $$  so I can conclude every $f_i' = 0$ so every $f_i =constant$  but not sure how to do it.. thx

I need to prove that if $f,g$ are analytic in the unit disk, and $|f|^2+|g|^2=1$ for all $z$ in the unit disk, then $f,g$ are constant.  This is an exercise question so it should not be very hard, but I don't know where to start. Any hint is appreciated.


I have a layer where I had 6 polygons. I then used the field calculator so I could get a column with the area of each of these polygons and I thought this would be applied to any other polygons I made after that, which was not the case since every new polygon appears as "NULL" in the area column. How do I make so the area is calculated automatically for all the rows?

Using QGIS, if I load a polygon layer and make a new column, how do I fill that column with the:   area of each polygon and another column with length of the perimeter of each polygon?


When modeling data sampled in the field, I often come across the problem of determining the Family of the dependend variable for GLM (or GLMM). An example: in an ecological study, I have ~ 60 patches. I have sampled territories of an animal species within these patches as well as a set of explanatory variables. The number of territories per patch (NTP) is the dependent variable in a GLM. NTP is integer with values between 0 and 14:     How can I test for the family of NTP? Any help appreciated as this is an issue many ecologists come across each time they conduct statistical analysis.  I am aware of  being a very similar question. However, it is not answered and the test case seems a bit different.

I have fish density data that I am trying to compare between several different collection techniques, the data has lots of zeros, and the histogram looks vaugley appropriate for a poisson distribution except that, as densities, it is not integer data. I am relatively new to GLMs and have spent the last several days looking online for how to tell which distribution to use but have failed utterly in finding any resources that help make this decision. A sample histogram of the data looks like the following:   I have no idea how to go about deciding on the appropriate family to use for the GLM. If anyone has any advice or could give me a resource I should check out, that would be fantastic.


I was about to ask a question on a Stack Exchange site but I didn't have any details to put in the body so I was deciding to post the question with just one sentence. Is that an OK thing to do on the Stack Exchange network or should I somehow find details for my question before I post it?


My phone started rebooting all by itself all the time after I did 2 things with it. Installed Snapdragon BatteryGuru and put it on learning mode (for an estimated 3 days I guess) so that I could start saving battery by the app learning my behavior, and cleaned RAM with CleanMaster. These were the only changes I've done, I don't remember which was first but soon my phone started rebooting whether I was handling it or not at random intervals. I've also noticed the phone was hot all the time, the Note 3 runs into some hot period with some frequency but not with that frequency. I've uninstalled both apps and it didn't work, wiped cache and it didn't work. The phone was still rebooting even on safe mode. After I wiped Dalvik with the help of TWRP, I thought the problem went away but when I hit the power button to turn the screen off, the phone rebooted and it will now always reboot when the screen turns off, even if it's just from the phone being inactive. Note 3 SM-N9003 VJUBMI6

My phone started rebooting all by itself all the time after I did 2 things with it. Installed Snapdragon BatteryGuru and put it on learning mode (for an estimated 3 days I guess) so that I could start saving battery by the app learning my behavior, and cleaned RAM with CleanMaster. These were the only changes I've done, I don't remember which was first but soon my phone started rebooting whether I was handling it or not at random intervals.  I've also noticed the phone was hot all the time, the Note 3 runs into some hot period with some frequency but not with that frequency. I've uninstalled both apps and it didn't work, wiped cache and it didn't work. The phone was still rebooting even on safe mode. After I wiped Dalvik with the help of TWRP, I thought the problem went away but when I hit the power button to turn the screen off, the phone rebooted and it will now always reboot when the screen turns off, even if it's just from the phone being inactive. It doesn't boot-loops, it just reboots, then after a random time, can be seconds, can be half an hour, it will reboot again. Note 3 SM-N9003 VJUBMI6.


I was on my iPhone 6s in my Gmail app and somehow deleted my All Mail folder.  This deleted all of my folders, inbox, sent, and drafts along with my trash and junk mail.  It wiped everything clean.  I have emails saved from 10 years prior.  I need to recover everything.  It never asked me to permanently delete.  It was a simple accident that I had no clue would delete everything.

Is it possible to recover an email that has been clicked on "delete forever" in the trash folder? I have accidentally clicked delete forever for an email but now I need to recover it.


In earlier times (with/without gold badge), when a user would hit "close" button for a "duplicate" question, it will automatically add a comment and mark a vote for the closing it.  With new "gold badge" rule, now it completely closes it. But I notice that sometimes, there is a opinion mismatch among the users which is expected. As a gold badge user, sometimes I feel that completely closing the Q is too strong an action. In such case, I can think of following ways:   Flag for moderator attention -- too slow Put a comment manually -- clumsy & unable to vote Vote for close & ask for opinion via comment -- not elegant   Is there any other way which I am missing or already proposed? The requirement is: At times, a gold badge user may still want to "propose" closing a Q as duplicate in the old school way.  It happens often. Here is the .

According to  , gold badge holders can now unilaterally close questions as duplicates. I hold seven gold badges for tags on SO, which means I can, on my own, close questions as duplicates for those tagged questions.  Simply put: DO NOT WANT.  However, I do not see any ability in SO (the only SE site I spend much time in) to opt out of any privileges, let alone this one.  Is there a spot that I'm just not seeing that allows me to turn off this new privilege?


So far I have that if I + J = R, then 1 ∈ I and/or 1 ∈ J. Then I = R and/or J = R. If both I = J = R, then IJ = I ∩ J = R must be true because we already know that multiplying every element in I or J by every element in R will end up giving us R again. So IJ = I ∩ J = R.  If I = R, but J ≠ R, then IJ = J = I ∩ J because we already know that when all elements of J are multiplied by all elements of R, the result is J again. Therefore, IJ = I ∩ J = J.  Therefore, it is true that if I + J = R, then IJ = I ∩ J.  Does this proof work or am I not able to say that 1 ∈ I or 1 ∈ J?

If $R$ is a commutative ring and $I$ and $J$ are ideals s.t. $I+J=R$ then show that $IJ=I\cap J$.  I've already shown that $IJ \subset I\cap J$, now I need to show the reverse inclusion.   I'm a bit lost, so far i'm just figuring out what pieces I have to work with.  Such as:  $\forall r\in R$ $\exists i\in I ,j\in J$ s.t. $i+j=r$  $\forall ij\in IJ$, $ij=i_1$ and $ij=j_1$ for some $i_1\in I$, $j_1\in J$.  Also, if I let $x\in I\cap J$, then $x=i_2=j_2=i+j$ for some $i_2\in I$, $j_2\in J$  Anyone, having problem getting to the conclusion here, thanks in advance


I want to remove a pattern from a string (using sed and pipes), but this pattern is not always the same and is defined previously on a variable.  this example mimics the desired behavior  toremove="Osiris"  mystring="Horus,Osiris,Apis"  mystring=$(echo $mystring | sed -e 's/$toremove//g')   no succcess so far. Output is the same as input,

I want to do:  cat update_via_sed.sh | sed 's/old_name/new_name/' > new_update_via_sed.sh   in my program.  But I want to use variables, e.g.  old_run='old_name_952' new_run='old_name_953'   I have tried using them but the substitution doesn't happen (no error). I have tried:  cat update_via_sed.sh | sed 's/old_run/new_run/' cat update_via_sed.sh | sed 's/$old_run/$new_run/' cat update_via_sed.sh | sed 's/${old_run}/${new_run}/'


What is the meaning of the expression "An X is an X is an X"? Judging from the sentences I found this expression in I'd say it means "every X is pretty much the same".  How did this expression originate? It is not exactly easy to google it given its structure.

I am reading  (I must say, with great delight but that's not relevant) and  Canadian is a Canadian is a Canadian A citizen is a citizen is a citizen.  I do not understand this structure. Why not just "A citizen is a citizen"? What is the meaning of repeating this?


I can't change Google Maps menu to English. English is my language of choice throughout Google, but in Google Maps the menu is in Russian. How can I change it to English?

My Chinese is still pretty poor, and my Korean is worse.  But Google Maps recently began showing me everything in Korean or Chinese.  Sometimes even a mixture of both. I can't find anything to change it.  My browser, if I don't catch it, switches me to maps.google.es, but that doesn’t make it Spanish.  I can follow an itinerary with difficulty, but choosing the best one it offers is a major problem.  How can I get it to do a language I am reasonably good at?  (English or Spanish preferred.)


Why does applying the following circuit on a $00$ state produce $|0\rangle \otimes  |+\rangle = \frac{1}{\sqrt{2}}(|00\rangle + |01\rangle)$. Shouldn't it produce $ |+\rangle \otimes  |0\rangle = \frac{1}{\sqrt{2}}(|00\rangle + |10\rangle)$?

I've noticed that Q# favors Little Endian. Meaning that most operations are designed for this type of encoding.  Is is it the same with Qiskit?


Suppose that a smooth manifold $M$ is a metric space and that $\Gamma$ is a discrete group of smooth isometries acting discontinuously on $M$. Show that the action is necessarily properly discontinuous.   Discontinuous means: each $x \in M$ has a neighborhood $U$ such that $\{h \in \Gamma ; hU \cap U \neq \emptyset\}$ is finite.  And properly discontinuous means both discontinuous and if $x,y \in M$ are not in the same orbit, then there are neighborhoods $U, V$ of $x,y$ such that $U \cap \Gamma V = \emptyset$.  Anyone can solve this problem? Thanks.

I was reading the article "The Geometries of 3-manifolds" by Peter Scott and in the end of page 406 he states the following:     If $G$ acts properly discontinuously on a space $X$, then $G$ is a   discrete subset of the space of all continuous functions $X \to X$   with the compact-open topology. The converse is false, in general, but   is true if $X$ is a complete Riemannian manifold and $G$ is a group of   isometries of $X$.   How do I prove the last statement?     If $X$ is a complete Riemannian manifold and   $G$ is a group of isometries of $X$ acting properly discontinuously on $X$, then $G$ is discrete.    Observation: We say a group $G$ of homeomorphisms of $X$ acts properly discontinuously on $X$ if for every compact $K \subset X$ the set $$\{g \in G: gK \cap K \neq \emptyset\}$$ is finite.


I've always had difficulty ascertaining the way to approach structuring a particular type of sentence re: the situation in the question title.   There are probably all sorts of ways to restructure this particular example in such a way so as to avoid the issue entirely, but unless that is, in fact, the general rule of thumb in these types of situations, I want to make sure we focus on the specific concept of dealing with two prepositions of this type rather than just dealing with the no doubt poor example. As follows:     "...the value of which, I might add, humans are completely delusional about."   What I want is to stick that "about" somewhere that is not the end of the sentence.  As I have done for "of", I know we often use "which" to make sure that our prepositions don't end up at the end of our sentences.    In the above example, if it was "the thing" that humans were delusional about, it would be easy to just end it with "[the thing], about which humans are delusional."  But instead, it's "the value OF the thing" about which humans are delusional.  So if I wanted to structure the sentence more or less like I've done, coming at the end of a larger monologue, as sort of an afterthought, I'm not sure how to squeeze the "about which" in there with the "of which" that's already there.  For instance, could I double use the same "which" somehow?  Or must I slide a second "which" in there to use with the "about"; if so, in what order should it go, exactly?    Note:  I realize that with this example, I could easily just add the words "is something", so as to say:  "...the value of which, I might add, is something about which humans are delusional."  But again, I want to focus on dealing with this concept in all contexts, rather than avoiding it here just because it happens to be easy.  (Also, even that sounds a bit repetitive to my ear, what with the two "which"s so close to each other.  The "I might add" is really there to try to add some separation but it isn't all that effective.)  This has been on my mind before more than once, and, if I recall correctly, I'm pretty sure I once heard Frasier Crane solve this for me with some fancypants word magic in exactly such a situation, and it sounded great. I want to say he somehow doubled down on a single "which"; something like "of about which".  The problem is that that doesn't really seem right to my ear when I try it now, but I can't for the life of me remember or figure out how else he might have done it.  Thanks in advance to anyone who will help scratch this itch.

Like many others, I commonly find myself ending a sentence with a preposition.  Yes, it makes me cringe.  I usually rewrite the sentence, but sometimes (in emails) I just live with it.  To, with... you know who you are.  Should I keep fighting myself on this one, or is it okay in some circumstances?


Fist timer to unix/ linux operating systems. I tried to download ubuntu to use in virtual box on a windows computer. then tried to boot the machine but got an error message that says "This kernel requires an x86-64cpu but only detected an i686 cpu. unable to boot. Please use a kernel appropriate for you cpu" Any suggestions as to how to fix this?

I was trying to install Ubuntu 12.04 in VirtualBox 4.2.12r84980. I see    this kernel requires an x86-64 CPU, but only detects an i686 CPU, unable to boot   But I am using a 64 bit Windows 8, and trying same .iso for trying Ubuntu. Then what is the problem?


I bought a Dell laptop used, and it had Ubuntu 14.04 on it, but I prefer Windows. I noticed that there was a sticker on the corner of my laptop that said "Windows Vista Basic" and another one that says, "Intel Core 2 Duo inside". I would like to switch back to Windows, but I don't know how. Also, I am not able to use a disc to switch because the disc drive doesn't work.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


Three points are placed at independently and at random in a unit square. What is the expected value of the area of the triangle formed by the three points?

"Three points are chosen uniformly and at random from a unit square. What is the expected value of the area of the resulting triangle?"  I need to do a research about that problem and i found this suggested solution: .  Now, I understand almost everything except anecdote (2) when he computes the expected value of $b$ and $v$.  I can't understand how he reaches those calculations.  If someone can explain to me this that would be great.  Thanks.


when i try to install windows 8.1 o.s to my laptop.it shows that the required cannot be selected showing something like drive 0 cannot be installed.i my Ubuntu o.s is in u.e.f.i mode.and the entire o.s is in a single partition which is under the owner of root..i cannot unmount the drive.


When I got Linux put onto my personal laptop, I wasn't asked to create a password.  Now, whenever my screen goes black, I've got to power it down and restart it in order to get back to the screen I was originally on.  How can I create a password so I don't have to do that any longer?

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


I have data set of different school in a certain area to assess the cause of reason behind student's cause of failure in the English exam. Data set has several kind of variable like continuous, categorical, variable with percentage value 0 to 100 etc.   DV : Percentage of student pass in the English exam (0 to 100)  IV :           - No of students in class (Discrete value)       - Average age of the teacher (Discrete value)       - Percentage of teacher has masters degree or higher (0 to 100)       - Quartile rank of students economic condition (1-4, poor to rich)       - Percentage of students get free meal at the school (0 to 100) etc.   I want to run a ordinary least square regression in the data set, is it possible to run this on the above mentioned variables or I need some modification before analysis.   I have already run the linear regression for the model and surprisingly got all are statistically significant. So my questions are     1. Is it correct? If not what are the flaws?     2. Does it necessary to use logistic regression by converting to category?

I have a study where many outcomes are represented like percentages and I'm using multiple linear regressions to asses the effect of some categorical variables on these outcomes.  I was wondering, since a linear regression assume that the outcome is a continuous distribution, are there methodological problems in applying such model to percentages, which are limited between 0 and 100?


This is the problem:     The random variables $X$ and $Y$ are independent and $N(0,1)$-distributed.   Determine         $E(X \mid X > Y )$,   $E(X + Y \mid  X > Y )$.      I go by the definition of $$f_{X \mid X>Y}(x) = \frac{\int_x^\infty f_{X,Y}(x,t)dt}{f_X(x)}= \cdots = (2\pi)^{-1/2} \int_x^\infty e^{-t^2/2} dt$$ but that function does not have a primitive. I thought about "getting" a Gamma under the int but I'm not sure on how to proceed here.     Edit 1. I got the following tip. If $(X,Y)$ is normal centered, there exists some nonnegative $(\sigma,\tau,\varrho)$ and $(U,V)$ i.i.d. standard normal such that $X-Y=\sigma U$ and $X=\tau U+\varrho V$. Thus, $$E(X\mid X\gt Y)=\tau E(U\mid U\gt0)+\varrho E(V\mid U\gt0)==\frac{2\tau}{\sqrt{2\pi}}.$$ But I do not see why the == is true. I also don't know how this would help me, do I pick $\tau$ and  $\varrho$ to be 1?

When $X$, $Y$ are bivariate normal, how can we calculate the conditional expectation $E(X\mid X>Y)$? A more concrete setting of this general problem can be referred .


I am trying to apply for visa student for the US, but I will have the South African  Refugee Travel Document instead of a regular passport. I am worried that they might not be able to issue a visa for me. What are the requirements for people like me to get a visa to US with a South African Refugee Passport?

I would like to know, whoever has travelled to the USA using the south african travel document  how did they do it?   What is the process and how will I go about it ?  Please respond . I am afraid of being rejected because they might think I am going there to stay because my document says refugee.


It might be possible here in India too, I haven't researched on it, but in one movie I have seen the guy is studying mathematics in MIT but his future plan was to study medicine at Harvard. I kept wondering how could he do that.  Here at India at 11th class we have to usually choose either Mathematics or Biology and then our eligibility changes accordingly.

Would it be out of the ordinary to get a Bachelors in Mechanical Engineering and then go for a Masters in something like Civil or Structural Engineering?  I don't know a lot about how transitioning to a Masters program works.. Do people usually continue on in the same field, or is branching out common?


That assassin that Arya frees seems to be invincible and says he can slay anyone.  (I don't know how he was captured in the first place.)  Arya is learning that same assassin art.  The red priests all seem invincible.  All the merchants of Essos seem to have much more wealth.  The Iron Bank on Essos.  The Targaryans actually came from across the sea with dragons and took over.  Plus only Westeros lives in the shadow of the threat from the Others.  Is there any explanation about why Westeros isn't just a vassal land to Essos?

Has any community of Essos ever invaded or attacked Westeros?  As I far as I know, only the Dothraki intended to invade Westeros, because Drogo promised that to Daenerys.  What about the other communities of Essos? Are there none with sailing skills?


I'm an undergraduate student in a research group. I'm a little bit confused about how can I call my professor appropriately. The graduate students in the group just call him by his name, but I think it would be a little bit rude for me to do that. I want to be more polite, but I also feel like it's a bit weird if I add 'Dr./'Prof.' every time I'm trying to call him. Any suggestions about what I could do?

At US universities, how should one address a professor while talking to him or her? In my home country, we usually address the professors as either "sir" or "madam" while talking about our queries in person.   What's the norm at US universities?


I'm a beginner and currently doing the "Programming for everybody" course of the University of Michigan.  I wrote this code myself for task 7.2 and to my understanding the code is basically done. But for some reason at line 7 of the output (you'll see when you start the program), the program starts adding 11 additional digits at the end of the sum, as if I just substracted "0.00000000000000001" from the sum.  I just can't wrap my head around why this happens, does anybody of you see the problem?  The text-file used for this can be found here:   Thanks a lot.  file = ("mbox-short.txt") text = open(file) lcount = 0  for line in text:     line = line.rstrip()     if not line.startswith("X-DSPAM-Confidence"):         continue     lcount = lcount + 1     print()     print("Line: ", lcount)     #print(line)     a = line.find(":")     numbers = line[a+1:]     numbers = numbers.rstrip()     numbers = float(numbers)     print("New Number: ", numbers)      if lcount > 1:         print("Old sum: ", numbers_sum, "+", numbers)         numbers_sum = numbers_sum + numbers         print("New sum: ", numbers_sum)     else:         numbers_sum = numbers  numbers_avg = numbers_sum/lcount print(numbers_avg)

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I have pass the data from Project1.java to Claims.java and named them to name and result. They can show on c.setText. But when I want to save them in SQLite database, app crashed.  Claims.java    String result;     String name;     fk = bundle.getLong("ab");           @Override             public void onActivityResult(int requestCode, int resultCode, Intent data) {                 int button = data.getIntExtra("k1", 0);                  if (button == 1) {                     switch (requestCode) {                         case 0:                             result = data.getStringExtra("text");                             name = data.getStringExtra("a");                              as=Long.parseLong(result);                             c.setText("            " + name + "------" + "RM " + result);                             break;                          case 1:                              result = data.getStringExtra("text");                             name = data.getStringExtra("a");                              as=Long.parseLong(result);                             c.setText("            " + name + "------" + "RM " + result);                             break;       button.setOnClickListener(new View.OnClickListener() {                 public void onClick(View arg0) {                      if ((name != null && name.trim().length() > 0) && (result != null && result.trim().length() > 0)) {                         SB.insertStaffBenefit(name, result, fk);                      } else {                         Toast.makeText(getActivity(), "A", Toast.LENGTH_LONG).show();                     }                  }              });      11-04 17:09:40.876  20272-20272/com.example.project.project   E/AndroidRuntime﹕ FATAL EXCEPTION: main       Process: com.example.project.project, PID: 20272       java.lang.NullPointerException               at com.example.project.project.Claims$7.onClick(Claims.java:153)               at android.view.View.performClick(View.java:4654)   After did like what @Mohit suggested, now I get another error     11-05 01:45:01.612    2505-2505/com.example.project.project   E/AndroidRuntime﹕ FATAL EXCEPTION: main       Process: com.example.project.project, PID: 2505       java.lang.NullPointerException: Attempt to invoke virtual method 'long   com.example.project.project.API.StaffAPI.insertStaffBenefit(java.lang.String,   java.lang.String, long)' on a null object reference               at com.example.project.project.Claims$7.onClick(Claims.java:153)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I've just got a new server with native ipv6. I want to attach multiple ipv6 ips to eth1, but the only way I can see to do so is to attach them individually:  i.e.  address 2607:f0d0:xxxx:xxxx::2 address 2607:f0d0:xxxx:xxxx::3 address 2607:f0d0:xxxx:xxxx::4   Is it possible to bind whole subnets of ipv6 to a single network interface on debian? My server host tells me I have 18,446,744,073,709,551,616 ipv6 addresses for that server, surely it gets to be a nightmare to manage if they all have to bound individually (plus ifconfig would look messy).  Does anyone have a solution?

I know that the ip tool lets you bind multiple addresses to an interface (eg, ). Right now, though, I'm trying to build something on top of IPv6, and it would be really useful to have an entire block of addresses (say, a /64) available, so that programs could pick any address from the range and bind to that. Needless to say, attaching every IP from this range to an interface would take a while.  Does Linux support binding a whole block of addresses to an interface?


I want to get comma separated values from multiple rows in SQL. From above picture I want to get type column with comma separated values.

Using MySQL, I can do something like:  SELECT hobbies FROM peoples_hobbies WHERE person_id = 5;   My Output:  shopping fishing coding   but instead I just want 1 row, 1 col:  Expected Output:  shopping, fishing, coding   The reason is that I'm selecting multiple values from multiple tables, and after all the joins I've got a lot more rows than I'd like.  I've looked for a function on  and it doesn't look like the CONCAT or CONCAT_WS functions accept result sets.  So does anyone here know how to do this?


I need to check if a form field is a valid URL (it can be done through HTML5, but not every browser has it yet), and I can't find a good URL checker function. It's strange, because with email-checking, there are lots of already-done functions.  I've seen (I just discovered it) the filter_var() function, but as I read, there are some issues with urls. I can find some regular expressions, but they don't seem very exhaustive.  Do you know any good url checker function?

I've been looking for a simple regex for URLs, does anybody have one handy that works well?  I didn't find one with the zend framework validation classes and have seen several implementations.


Let's consider a system of $N$ point particles. Let's also assume that acceleration of each particle is a function of positions of all the particles. I assume that for such a system we can prove that the motion of the system is described by Lagrangian equations of motion. How exactly can it be done? ADDED I do not ask why Lagrangian is defined as $L = T - V$. What I am interested is how to derive Lagrangian equations of motion from Newtonian equations of motion.

Is there a proof from the first principle that for the Lagrangian $L$,    $$L = T\text{(kinetic energy)} - V\text{(potential energy)}$$  in classical mechanics? Assume that Cartesian coordinates are used. Among the combinations, $L = T - nV$, only $n=1$ works. Is there a fundamental reason for it?  On the other hand, the variational principle used in deriving the equations of motion, Euler-Lagrange equation, is general enough (can be used to to find the optimum of any parametrized integral) and does not specify the form of Lagrangian. I appreciate for anyone who gives the  answer, and if possible, the primary source (who published the answer first in the literature).      Notes added on Sept 22: - Both answers are correct as far as I can find. Both answerers were not sure about what I meant by the term I used: 'first principle'. I like to elaborate what I was thinking, not meant to be condescending or anything near to that. Please have a little understanding if the words I use are not well-thought of. - We do science by collecting facts, forming empirical laws, building a theory which generalizes the laws, then we go back to the lab and find if the generalization part can stand up to the verification. Newton's laws are close to the end of empirical laws, meaning that they are easily verified in the lab. These laws are not limited to gravity, but are used mostly under the condition of gravity. When we generalize and express them in Lagrangian or Hamiltonian, they can be used where Newton's laws cannot, for example, on electromagnetism, or any other forces unknown to us. Lagrangian or Hamiltonian and the derived equations of motion are generalizations and more on the theory side, relatively speaking; at least those are a little more theoretical than Newton's laws. We still go to lab to verify these generalizations, but it's somewhat harder to do so, like we have to use Large Hadron Collider. - But here is a new problem, as @Jerry Schirmer pointed out in his comment and I agreed. Lagrangian is great tool if we know its expression. If we don't, then we are at lost. Lagrangian is almost as useless as Newton's laws for a new mysterious force. It's almost as useless but not quite, because we can try and error. We have much better luck to try and error on Lagrangian than on equations of motion. - Oh, variational principle is a 'first principle' in my mind and is used to derive Euler-Lagrange equation. But variational principle does not give a clue about the explicit expression of Lagrangian. This is the point I'm driving at. This is why I'm looking for help, say, in Physics SE. If someone knew the reason why n=1 in L=T-nV, then we could use this reasoning to find out about a mysterious force. It looks like that someone is in the future.


This is the problem I have to solve, I tried many times using the definition, but the result is not the one required.  Let $(X_n)_{n\in \Bbb N}$ be a sequence of independent and identically distributed random variables with $ \Bbb P(X_i=0)=p$ and $ \Bbb P(X_i=1)=1-p$ for all $ i \in \Bbb N $. Show that for $ p \in [0,1) $ $ \lim_{n\to \infty} {\sum_{i=1}^n X_i \over \sum_{i=1}^n X^2_i } = 1 $ almost surely.  Thanks in advance

I want to show that: $\lim_{n \rightarrow \infty} \frac{\sum_{i=1}^{n} Y_i}{\sum_{i=1}^{n} Y_i^2} = 1$ almost surely given that $(Y_n)$ is a sequence of independent and identically distributed random variables, $P(Y_i = 0) = a, P(Y_i = 1) = 1-a$.  I am confused about this 'almost surely'. What is a sequence of random variables? I guess somehow I can maybe convert the sum into a product and then use the independence...Any hints?  Edit: found out that 'almost 'surely' means that the probability of it is 1. Also, in our case we actually just have an IID.


What does the >|-redirection in bash do?  I just found out, that echo text >| somefile creates the file somefile (if not existing yet), and fills it with text. Similar as echo text > somefile would do.  Further experiments suggest that the >|-redirection behaves as the >-redirection does.  So, what is the >|-redirection exactly?  Since it's hard to google for the string ">|", I could not really search the web (so I have added "greater-pipe" in the title of this question since that is google-able).

I have just seen this written down;  $ some-command >| /tmp/output.txt   Vertical pipes are used in standard redirects "piping" the output of one command to another, is >| in fact completely useless as it would be the same as just > in this scenario?


Im trying to figure out how to reverse the string temp when I have the string read in binary numbers   istream& operator >>(istream& dat1d, binary& b1)     {                   string temp;       dat1d >> temp;     }

How do you reverse a string in C or C++ without requiring a separate buffer to hold the reversed string?


Suppose the following conditions hold true:  (1) The function $f$ is analytic and contractive in the open unit disk.  (2) $f(0)=0$.  (3) $\exists z_1 \ne z_2 \in B(0,1)$, $|z_1|=|z_2|$, $f(z_1)=f(z_2)$.  Prove that $|f(z_1)|=|f(z_2)| \leqslant |z_1|^2=|z_2|^2$.

Let $f\in H(B(0,1))$, $f(0)=0$, $f(B(0,1))\subset B(0,1)$. Suppose there are 2 different points $z_1$,$z_2\in B(0,1)$, s.t. $|z_1|=|z_2|$, $f(z_1)=f(z_2)$. Show that $|f(z_1)|=|f(z_2)|≤|z_1|^2=|z_2|^2$.    I have used the Schwarz-Pick Proposition to prove that $|f(z_1)|=|f(z_2)|≤|z_1|=|z_2|$ directly, but that is not enough. Thank you for help!


My approach so far:   Using  I'm expressing the above limit as $((1+\frac{1}{\frac{n}{x_n}})^\frac{n}{x_n})^{x_n}$ and then using the property (?) that if $x_n \rightarrow x$ and $a_n \rightarrow a$, then $x^{a_n}_n \rightarrow x^{a}$. But I'm proving this last property by taking log on both sides (suppose $a,x > 0$). My question is isn't that somehow using the property I'm required to prove and hence is this valid?

In Statistical Inference by George Casella, Lemma 2.3.14 states that: $\text{Let }a_1,a_2,...\text{be a sequence of numbers converging to }a\text{, that is, }\lim_{n \to \infty}a_n=a\text{. Then}$ $$\lim_{n \to \infty}\left(1+\frac{a_n}{n}\right)^n = e^a$$ Can somebody give me some hint for this? My first instinct is that since n is in the denominator, then that limit term would just be 1. However, this is obviously not correct.


When attempting to install Dolphin-Emu, I have come across a un-met dependences that are preventing the installation. I installed Dolphin-Emu as a PPA, so I could manually install the package. Every time I attempt to install, this is the code that I am using, and the message I get.  $ sudo apt-get install dolphin-emu Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:     The following packages have unmet dependencies:     dolphin-emu : Depends: libstdc++6 (>= 4.9) but 4.8.4-2ubuntu1~14.04 is to be installed E: Unable to correct problems, you have held broken packages.   Any and all help would be appriciated.

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


This is a very basic question, and maybe a silly one, but I'm struggling to understand  the actual definition of a probability distribution.  In Wasserman's "All of Statistics", for example, he says that "if $\Omega$ is finite and if each outcome is equally likely, then $\mathbb{P}(A) = |A| / |\Omega|$, which is called the uniform probability distribution."   This suggest to me that a probability distribution refers specifically to the probability measure chosen, i.e. a probability distribution is the measure associated with a probability space. Yet on Wikipedia and elsewhere online, a probability distribution is only defined within the context of some random variable, e.g. "A probability distribution is a function that describes the possible values of a random variable and their associated probabilities". So my question is, is a probability distribution the measure on a given space, or is it the pdf/pmf of a given random variable? When we say we "draw a random variable" from a probability distribution, does that mean we construct a random variable from a given probability space with that probability measure, or that our random variable has that pdf/pmf? Is this a meaningful distinction?

I mean statements such as: "the probability distribution of X" or "its probability distribution". I am quite confused about such expressions.  Could someone please explain the relationship between, Probability, Probability Distribution, density function? I have checked on Wikipedia for a while, still only clear about that, density function can be used to calculate the probability.


$ f $ is a differentiable function on the interval $ [a, + \infty) $ with $ a \in \mathbb{R} $  Prove that if $ \lim_{x \to + \infty} f'(x) = + \infty $, then $ \lim_{x \to + \infty} f(x) = + \infty $     $ f $ is a differentiable function on the interval $ [a, + \infty) $, so by the mean value theorem we have:   $ \exists c \in (a,x): f'(c) = \frac{f(x) - f(a)}{x-a}$  $\implies f(x) = f(a) + (x-a)f'(c)$  $\implies\lim_{x \to +\infty} f(x) = \lim_{x \to +\infty}(x-a)f'(c) + f(a) $  I don't know how to proceed to prove $ \lim_{x \to + \infty} f'(c) = + \infty $ because we have: $ a < c < x $. Thank you.

Let $f$ be differentiable and let $\lim_{x \to \infty}f'(x)=+\infty$ prove that: 1) $\lim_{x \to \infty}(f(x)-f(x-1))=+\infty$ and 2) $\lim_{x \to \infty}f(x)=+\infty$.  1) I'll prove by contradiction. Let $\lim_{x \to \infty}(f(x)-f(x-1))=a$, where $a$ is from and $\Bbb R$. $\lim_{x \to \infty}(f(x)-f(x-1))=\lim_{x \to \infty}\frac{f(x)-f(x-1)}{x-(x-1)}=\lim_{x \to \infty}f'(c)=a$, where c is from $(x-1,x)$ (mean value theorem). As $x$ goes to infinity so does $c$ i.e. we have that $\lim_{x \to \infty}f'(c)=\lim_{c \to \infty}f'(c)=a$. Which is a contradictition since we have that  $\lim_{x \to \infty}f'(x)=+\infty$ .   2) I will also prove this by contradiction. We have that $\lim_{x \to \infty}f(x)=a$ This is equivalent to $\lim_{x \to \infty}f(x)-f(x-1)=0$. I use mean value theorem and get $\lim_{x \to \infty}(f(x)-f(x-1))=\lim_{x \to \infty}\frac{f(x)-f(x-1)}{x-(x-1)}=\lim_{x \to \infty}f'(c)=0$, where c is from $(x-1,x)$. As $x$ goes to infinity so does $c$ i.e. we have that $\lim_{x \to \infty}f'(c)=\lim_{c \to \infty}f'(c)=0$. Which is a contractition since we have that  $\lim_{x \to \infty}f'(x)=+\infty$ .


If I put <!DOCTYPE> in my HTML document then my browser will use HTML 5.0 to parse the document. If I don't use <!DOCTYPE> then which version of HTML will be used to parse the document?

What is DOCTYPE and why do I want to use it? What are the different DOCTYPEs I can use? What is the difference between standards and quirks mode, and what are some quirks I may run into with differently set DOCTYPEs?   Lastly, what is the proper DOCTYPE that I should be using?


how to show Debian distribution name used in ubuntu?  $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 18.04.3 LTS Release:    18.04 Codename:   bionic   no debian release name here

I have some software packages customised for Ubuntu 10.04, 10.10 and 12.10, but now I have to install them on Debian Squeeze. I have been unable to Google for a mapping between specific Ubuntu and Debian versions. Can someone here help?   Specifically I want to know which Ubuntu version corresponds to Debian Squeeze.


If photons have a speed limit (speed of light), what happens when you shoot photons through a flashlight but you yourself already have some speed? Do the photons from the flashlight only travel at [speed of light]-[your speed]?  Example: if solar system, galaxy and earth rotation movements were nonexistent and only earth orbital speed existed (30000 m/s), and you were to shoot photons in the approximate same direction the orbital movement is pointing at one time, would the speed of those photons be 299792458 - 30000 = 299762458 m/s ?  If that's the case isn't it possible to determine all movements the earth is suffering in relation to whatever object by measuring the speed of light in various directions over some amount of time?

The title says it all.  If I was on a bus at 60 km/h, and I started walking on the bus at a steady pace of 5 km/h, then I'd technically be moving at 65 km/h, right?  So my son posed me an interesting question today: since light travels as fast as anything can go, what if I shined light when moving in a car?  How should I answer his question?


There are a lot of textbooks available for this subject, however what is "the best" (IYO) textbook/reference guide? This is assuming the student has zero background in the subject and simply wants to have the different disciplines briefly laid out and explained.

Every once in a while, we get a question asking for a book or other educational reference on a particular topic at a particular level. This is a meta-question that collects all those links together. If you're looking for book recommendations, this is probably the place to start.  All the questions linked below, as well as others which deal with more specialized books, can be found under the tag  (formerly ).  If you have a question to add, please edit it in. However, make sure of a few things first:   The question should be tagged  It should be of the form "What are good books to learn/study [subject] at [level]?" It shouldn't duplicate a topic and level that's already on the list   Related Meta:


Okay, so it might seem like a trivial question, but when I suddenly stop my bike (not really fast), I lose balance. Why is that? What keeps me from falling while riding it?  EDIT : The answers in the other question either use terms I don't understand, or don't explain it in a simple and satisfactory way.

Why does a bike/bicycle fall when its speed is very low or close to zero and is balanced when going with a high speed?


I want a regex to extract a value from a string but can´t make it work :( regex is hard!  const myString = "the user id is: [user]10[/user]"   this is my regex  (?:[user])([\s\S]*)(?:[\/user])   but I´m not getting a match

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


With an array of elements, and an input-file I want to loop through the array and match each element with the input-file. I then want to get the line in the input-file where this element is occurring and the 3 lines that follows directly beneath. I have tried doing it this way:  for variable in $array do awk -v var="$variable" '/var/{x=NR+3}(NR<=x){print}' inputfile.txt done   But this did not return the desired out put. I then tried grep:  for variable in $array do grep -A 3 "$variable" inputfile.txt done   And this works. I guess I solved my problem, but as I would like to get a better understanding of awk, I decided to post this question, as I am curious to know what I am doing wrong when I try and feed awk a variable. I think I might be confused because the awk piece I have picked up, is without a BEGIN part? I am guessing a BEGIN part is assumed , and not necessary? Can my problem be solved with awk? Is awk the best tool for this task? And can my awk example be rewritten to have a BEGIN and END section, so it matches the examples and tutorials in awk I have looked at elsewhere on the internet? Thanks

Having the following in one of my shell functions:  function _process () {   awk -v l="$line" '   BEGIN {p=0}   /'"$1"'/ {p=1}   END{ if(p) print l >> "outfile.txt" }   ' }   , so when called as _process $arg, $arg gets passed as $1, and used as a search pattern. It works this way, because shell expands $1 in place of awk pattern! Also l can be used inside awk program, being declared with -v l="$line". All fine.  Is it possible in same manner give pattern to search as a variable?  Following will not work,  awk -v l="$line" -v search="$pattern" '   BEGIN {p=0}   /search/ {p=1}   END{ if(p) print l >> "outfile.txt" }   '   ,as awk will not interpret /search/ as a variable, but instead literally.


I recently performed a code audit on client, I found these lines of code that was subjected to a blind SQL injection  Code snippet:  <?php if ($_GET['id'] != ''){ $groepsindeling = $_GET['id']; } else { $groepsindeling = $_GET['group']; } breadcrumb($groepsindeling); ?>  <?php $groep = "SELECT * FROM `menubalk` WHERE `webnr` LIKE '%$webnr-%' AND `hoofdgroep` = '$_GET[id]' ORDER BY `naamt1` ASC"; $groepres = mysql_query($groep); while ($groeprij = mysql_fetch_array($groepres)){ ?>   I patched it immediately by using the mysqli_real_escape_string() function.  New code:  <?php if ($_GET['id'] != ''){  $groepsindeling = mysqli_real_escape_string($_GET['id']);  settype($groepsindeling, "integer");  }  else { $groepsindeling = mysqli_real_escape_string($_GET['group']); } breadcrumb($groepsindeling); ?>  <?php $groep = "SELECT * FROM `menubalk` WHERE `webnr` LIKE '%$webnr-%' AND `hoofdgroep` = '$_GET[id]' ORDER BY `naamt1` ASC"; $groepres = mysql_query($groep); while ($groeprij = mysql_fetch_array($groepres)){ ?>   I did further testing to see if the code would work it worked against the boolean based blind SQL injection, but it seems like a failure as a time based blind SQL injection is still applicable here.  All suggestions are appreciated.

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I have two sons now, one is of my former husband's side and older than the second son of my side from matrilineal marriage. The first son won't leave the succession line. I can't conspire to murder him since he's my child.  What must I do to take him out and bring my second son forward?  EDIT. A bit of update, that stupid non-dynastic heir somehow inherited a petty kingdom nearby, meaning he was not of my court anymore, there was nothing I could do. I could not ask him to take the vows (since he's not my courtier), couldn't imprison him though I was willing to suffer the opinion penalty. I tried to fabricate claim and declare war with hope to capture him as POW but wasn't a success. He took over the kingdom after my passing, leaving my dynasty to oblivion shame and putting an end to yet another noble house that couldn't survive the feudal hardship.

Everything was perfect. I have a good and young ruler, who has passed on some good genes to his sons. I also had a lot of spare lands, so I could make my heir a duke and doubly count when he came of age.  My mistake was to marry him off to some scheming wench. I knew it would end like this, but her stats were just too great to resist!  Anyway, a few years down the road, and my trusty spy master lets me know that my beloved son is looking to usurp me. Not cool! I demand that he end the plot, and decide to see how this develops.  Shortly thereafter, he suddenly dies (not by my hand — likely the wife is the culprit). My second eldest son becomes my new heir and favourite, however all the titles are inherited by my clubfooted grand daughter aged two. Curses!  Now, what I really wanted, was to imprison and disown my traitorous son followed by swift justice of the axe. Not sure what my other vassals would think of that idea, but I had a just reason for imprisonment at least.  Option number two, is to start plotting for my dearly beloved grand daughters untimely demise, but I'm not sure how that would work out either.  The situation is this. I'm young (40ish) and well-liked. I have a new heir, but I'd prefer to keep my lands for myself and give him the ones of the previous heir — one duchy and two counties currently held by my grand daughter. The duchy can be revoked free of charge, as I hold a claim to it. She has no siblings. I am da King. I have limited crown authority, but can bump it up to medium if it suits me.    So my questions to you are as follows:   Is it possible to disown a son, considering I have just cause for imprisonment? An execution would of course settle the deal, but my other vassals would probably find me "cruel". Is it possible to plot against a character which is not yet of age? What would happen if she suddenly died with no heir? Would all her titles be returned to the king or duke (i.e. me)?   EPILOGUE I had savegames before and after, so I decided to test a few things.   I could imprison my quisling of a son. I could also seize all his titles and banish him from my lands, but he would remain an heir, even if he wasn't officially a prince. I guess I could have let him rot in jail, as it seems prisoners often die in custody, but it would be a risky bet. After the unfortunate death of my old heir, it seems some strange rules apply regarding the remaining titles. The dukal title I could simply revoke for free (although at a opinion penalty from the duchess). Should she die today, one of the counties would be inherited by her younger sister, and the other would be inherited by me.   I found this to be an interesting development: Turns out my new heirs wife suddenly died. Who did he marry, other than the same scheming hag who presumably killed off his brother, and made an attempt at me? By a suspicious coincidence, I died not very long after. Such is the effects of the deceitful and ambitious traits combined with a really dope intrigue stat. ;)


I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


My approach to avoid sql injection::Html form  <form method="post" action="" style="padding:0;">
    <input type="text" name="firstname" value="" placeholder="First Name">

     <input type="text" name="Email" value="" placeholder="Your Email">

   <input type="submit" name="Login" value="Submit">
  </form>   Using ajax I am submitting my form and I also implemented captcha to my   form.     On the action file, followed is the code which save data to database as :     if(isset($_POST['Login'])&& ( $_POST['Login'] )) // submit button name    {      if($_POST['type_code']==$_SESSION['vercode']) // checking captcha code     {       $firstname = strip_tags($_POST['firstname']);       $email = strip_tags($_POST['email']);       $phone = $_POST['phone'];       $sql = "INSERT INTO table_name (firstname,email,phone)       VALUES ('".$firstname."', '".$email."','".$phone.")";       if ($conn->query($sql) === TRUE) {          echo ‘records save successfully’;        }       Else       {          Echo ‘not saved data’;        }   But after cross-site scripting scan I got lots of sql injection bugs               For example ::                 URL encoded POST input firstname was set to ttqevjod" onmouseover=prompt(949671)  The input is reflected inside a tag parameter between double quotes.     To avoid such bugs my second approach was to restrict user from entering escape sequence characters into text field  This is as follow::     1.  Check on key press event        function blockSpecialChar(id)       {           var spclChars = "!@#$%^&*,\'\"(;:?.|-_)<>&[]{}+=`\/";            var content =  $('#'+id).val();                      for (var i = 0; i < content.length; i++)                         {                              if (spclChars.indexOf(content.charAt(i)) != -1)                              {                                 alert ("Special characters are not allowed.");                                  $('#'+id).val('');                                  return false;                             }                         }                  }    While saving data      if(isset($_POST['Login'])&& ( $_POST['Login'] )) // submit button name            {                if($_POST['type_code']==$_SESSION['vercode']) // checking     captcha code                {      $firstname = htmlspecialchars ($_POST['firstname']);      $email = htmlspecialchars ($_POST['email']);      $phone = htmlspecialchars($_POST['phone']);      $sql = "INSERT INTO table_name (firstname,email,phone)       VALUES ('".$firstname."', '".$email."','".$phone.")";      if ($conn->query($sql) === TRUE) {         echo ‘records save successfully’;      }     Else     {        Echo ‘not saved data’;        }   But my supervisor said this is wrong method of preventing  sql   injection. Please guide me right way of preventing sql injection.


I'm trying to find the correct way between "left- and right-hand side" or  "left and right-hand side".

If multiple hyphenated terms share the same latter half, and I wish to list them without repeating that latter half, how should the hyphens be placed?  For example:     I will be investigating control issues in ground-based, water-based, and air-based robots.   If I do not want to repeat based, could I write:     I will be investigating control issues in ground-, water-, and air-based robots.   Is it correct to just leave a hyphen dangling after ground and water?  If not, how should it be written? I know the original sentence doesn't sound too bad, but I really just want to know the punctuation rule (or the convention in American English if there is no rule).


Running the command sudo apt-get update | grep Ign in bash of my Ubuntu 15.10 I got the following:    Ign http://dl.google.com stable InRelease Ign http://dl.google.com stable InRelease Ign http://dl.google.com stable/main Translation-en_US Ign http://dl.google.com stable/main Translation-en Ign http://dl.google.com stable/main Translation-en_US Ign http://dl.google.com stable/main Translation-en   Should I worry about these ignored lists of packages? Should I worry about duplication of these lists? How can I fix it?  UPD: The content of my /etc/apt/sources.list file:  # deb cdrom:[Ubuntu 15.04 _Vivid Vervet_ - Release amd64 (20150422)]/ vivid main restricted  # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://ua.archive.ubuntu.com/ubuntu/ wily main restricted deb-src http://ua.archive.ubuntu.com/ubuntu/ wily main restricted  ## Major bug fix updates produced after the final release of the ## distribution. deb http://ua.archive.ubuntu.com/ubuntu/ wily-updates main restricted deb-src http://ua.archive.ubuntu.com/ubuntu/ wily-updates main restricted  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://ua.archive.ubuntu.com/ubuntu/ wily universe deb-src http://ua.archive.ubuntu.com/ubuntu/ wily universe deb http://ua.archive.ubuntu.com/ubuntu/ wily-updates universe deb-src http://ua.archive.ubuntu.com/ubuntu/ wily-updates universe  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu  ## team, and may not be under a free licence. Please satisfy yourself as to  ## your rights to use the software. Also, please note that software in  ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://ua.archive.ubuntu.com/ubuntu/ wily multiverse deb-src http://ua.archive.ubuntu.com/ubuntu/ wily multiverse deb http://ua.archive.ubuntu.com/ubuntu/ wily-updates multiverse deb-src http://ua.archive.ubuntu.com/ubuntu/ wily-updates multiverse  ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://ua.archive.ubuntu.com/ubuntu/ wily-backports main restricted universe multiverse deb-src http://ua.archive.ubuntu.com/ubuntu/ wily-backports main restricted universe multiverse  deb http://security.ubuntu.com/ubuntu wily-security main restricted deb-src http://security.ubuntu.com/ubuntu wily-security main restricted deb http://security.ubuntu.com/ubuntu wily-security universe deb-src http://security.ubuntu.com/ubuntu wily-security universe deb http://security.ubuntu.com/ubuntu wily-security multiverse deb-src http://security.ubuntu.com/ubuntu wily-security multiverse  ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. deb http://archive.canonical.com/ubuntu wily partner # deb-src http://archive.canonical.com/ubuntu vivid partner   UPD2  I have two additional repos:   /etc/apt/sources.list.d/google-chrome.list /etc/apt/sources.list.d/google-earth.list   The content of first one is  deb http://dl.google.com/linux/chrome/deb/ stable main   The content of the second one is  deb http://dl.google.com/linux/earth/deb/ stable main   If I comment the last string then the duplication disappears. Thus, I guess, there is no problem with the duplication.

I had a bunch of errors in the output of sudo apt-get update:  duplicate entries and 404 not found errors.  Figured those out, I hope: I removed PPAs that didn't have any packages associated with them, then I removed out a duplicate entry in /etc/apt/sources.list.  It seems I have royally buggered it up.  Now most of the lines say Ign when I do sudo apt-get update.  How do I go about straightening out what I have screwed up?  I need to get rid of these Igns that are all over the place.  There are about 50% (eyeball guess) Igns!


As per Wikipedia,  are a way to maintain "a continuously growing list of records, called blocks, which are linked and secured using cryptography [... and] inherently resistant to modification of the data."  Blockchains are in current practical use, for example in the cryptocurrency . These implementations must make use of some particular approach to cryptography, which will involve assumptions intended to underwrite their security.  Are the current implementations of blockchain resistant to attacks using quantum computation?

Reading  entertaining piece of a QC enthusiast mining bitcoins with a Quantum Computer (although efficiently mining bitcoins with the current state of QCs is far-fetched, it is quite possible to be done in the next few years), I wonder how exactly will technologies already using Blockchain adapt to the change?  Are they currently being worked upon? How would post-quantum cryptography integrate with existing tech secured using today's cryptography algorithms?


What purpose does Triangle inequality serve while defining norms?   Is it important to render it as a distance metric?     What would happen if we let the condition loose?

There is a property in the axiomatization of metric space: $d(x,z)\le d(x,y)+d(y,z)$. I understand that property applies well when it come to the measure of distances among points. However, that property seems to be irrelevant in the definitions of continuity, open set and some other key concepts.  My topology book says that it is asserting "the transitivity of closeness", a vague term that loses me. So why is that property important? Why did the founders (if any) of topology consider it at the first place? And what if that property is missed?


I wanted to see a list of the applications installed on my "Trusty Tahr" I ran this command in the terminal   dpkg --list   I got a list that displayed fine except that it cuts off about halfway the list, I can't see any applications prior to application names starting with the letter "P". How can I scroll past that?

I have a running log, it outputs a lot to the terminal. Unfortunately, when I try to scroll up and view older output, it appears there is a limit. And I am unable to scroll past a certain point. On the Mac, the terminal allows you to scroll up to the start of the session. Is there a way to do this in ubuntu terminal?


I want to put a 2D image onto a 3D object. I have downloaded the image, and just can't find out how to add it onto the object. Thanks! (v2.80.75)

I am creating a model of a glass and I would like to put a drawing on it (a png picture).  I know how to do it using Blender Render, but not with Cycles Render. Help :)


I am giving a workshop in early April. I would like to give each participant a memory stick with the PowerPoint slides and some freeware software relative to the topic of the workshop. I was given a large quantity of memory sticks to "recycle" (I'm on a strict budget--everything comes out of my own pocket) that have an obsolete version of the DigSafe manual. The partition containing the document shows as a CD drive when I insert one into a computer.  How can I reformat these devices to remove the "CD" partition? I did find an old thread suggesting using dd and fdisk to format this type of device. Will that work in my case?  (It's not the end of the world if I can't -- my poor audience will just have to suffer with receiving the requirements of Dig Safe. Hi Hi).

In Windows there is a straightforward "Format" option in a flash drive's right-click pop-up menu. Where's that in Ubuntu?


Suppose I have this object:  let obj1 = { key1: 'value1', key2: 'value2' }   And I have a different object like this:  let obj2 = { key3: 'value3', key4: 'value4' }   Is there a way of adding obj2 properties to obj1 and have this?  {     key1: 'value1',     key2: 'value2',     key3: 'value3',     key4: 'value4' }   I currently have this working but would want to know if there is an easier way:  for (prop in obj2) {         if (obj2.hasOwnProperty(prop)) {           obj1[prop] = obj2[prop];         }       }

I need to be able to merge two (very simple) JavaScript objects at runtime.  For example I'd like to:  var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' }  obj1.merge(obj2);  //obj1 now has three properties: food, car, and animal   Does anyone have a script for this or know of a built in way to do this?  I do not need recursion, and I do not need to merge functions, just methods on flat objects.


I have a 64GB Windows Server 2019 Standard server in my TEST Server. I have SQL Server 2019 CU9 Developer Edition and my the instance is consuming 21,199 MB as shown in sql_physical_memory_in_use_MB. I have 4 user databases.  Their sizes are approximately 5GB, 2GB, 400MB, and 200MB. My tempdb is configured to be 8GB at instance start-up. I'm trying to understand why my instance is using 21GB of memory.  Just worried about a possible memory leak. Can anyone calm my nerves? SELECT     (CASE WHEN ([database_id] = 32767) THEN 'Resource Database' ELSE DB_NAME (database_id) END) AS 'Database Name',     SUM(CASE WHEN ([is_modified] = 1) THEN 1 ELSE 0 END) AS DirtyPageCount,     SUM(CASE WHEN ([is_modified] = 1) THEN 0 ELSE 1 END) AS CleanPageCount,     count(*)AS TotalPageCount,     cast(count(*) * 8192.0 / (1024.0 * 1024.0) as decimal(8,2)) as BufferPoolMB FROM sys.dm_os_buffer_descriptors GROUP BY database_id ORDER BY TotalPageCount desc GO  OUTPUT     Database Name DirtyPageCount CleanPageCount TotalPageCount BufferPoolMB     SFI_WMS 55 805665 805720 6294.69   tempdb 18648 210842 229490 1792.89   DBAtools 483 82035 82518 644.67   Resource Database 0 3896 3896 30.44   msdb 42 1898 1940 15.16   master 24 766 790 6.17   ReportServer 4 476 480 3.75   ReportServerTempDB 0 308 308 2.41   model 0 245 245 1.91     SELECT      physical_memory_in_use_kb/1024 AS sql_physical_memory_in_use_MB,      large_page_allocations_kb/1024 AS sql_large_page_allocations_MB,      locked_page_allocations_kb/1024 AS sql_locked_page_allocations_MB,     virtual_address_space_reserved_kb/1024 AS sql_VAS_reserved_MB,      virtual_address_space_committed_kb/1024 AS sql_VAS_committed_MB,      virtual_address_space_available_kb/1024 AS sql_VAS_available_MB,     page_fault_count AS sql_page_fault_count,     memory_utilization_percentage AS sql_memory_utilization_percentage,      process_physical_memory_low AS sql_process_physical_memory_low,      process_virtual_memory_low AS sql_process_virtual_memory_low FROM sys.dm_os_process_memory;   OUTPUT     sql_physical_memory_in_use_MB sql_large_page_allocations_MB sql_locked_page_allocations_MB sql_VAS_reserved_MB sql_VAS_committed_MB sql_VAS_available_MB sql_page_fault_count sql_memory_utilization_percentage sql_process_physical_memory_low sql_process_virtual_memory_low     21199 0 0 124464 21461 134093263 9673913 100 0 0     SELECT c.value, c.value_in_use FROM sys.configurations c WHERE c.[name] = 'max server memory (MB)';      value value_in_use     60288 60288

As soon as I start SQL Server with no application querying, in the task manager it starts to consume memory very fast till it consumes around 15GB. How can I resolve this issue?


Since the Monk Martial Arts feature grants the ability to choose either Str or Dex as the modifier would the unarmed and flurry of blows be considered as finesse? the mechanics are essentially the same. This question is primarily for the purpose of figuring out if the Rogue Sneak Attack will work with a Monk Unarmed strike and Flurry of blows.

So a situation came up last night where a player with a monk/rogue was flanking (I use the optional flanking rules to grant advantage) an enemy. He was armed with a shortsword, but even with advantage, he missed the attack roll and thus did not get to use his sneak damage.   Since he had taken the Attack action with a monk weapon (shortsword), he could make an unarmed strike as a bonus action, as granted by the monk's Martial Arts feature. He still has advantage on that role since nobody had moved and the attack hit. But then the issue came up; is unarmed strike a finesse weapon? Is it eligible for sneak attack?  I ruled yes and allowed the sneak damage on this attack, but should I have allowed this or strictly should this not have worked?


Background  I'm working on a bash script to automate the process of building half a dozen projects that live in the same directory. Each project has two scripts to run in order to build it:  npm install npm run build   The first line will fetch all of the dependencies from npm. Since this step takes the longest, and since the projects can fetch their dependencies simultaneously, I'm using a background job to fetch everything in parallel. (ie: npm install &)   The second line will use those dependencies to build the project. Since this must happen after all the Step 1s finish, I'm running the wait command in between. See code snippet below.  The Question  I would like to have my script exit as soon as an error occurs in any of the background jobs, or the npm run build step that happens afterward.  I'm using set -e, however this does not apply to the background jobs, and thus if one project fails to install it's dependencies, everything else keeps going.  Here is an simplified example of how my script looks right now.  build.sh  set -e  DIR=$PWD  for dir in ./projects/**/ do     echo -e "\033[4;32mInstalling $dir\033[0m"     cd $dir     npm install & # takes a while, so do this in parallel     cd $DIR done  wait # continue once the background jobs are completed  for dir in ./projects/**/ do     cd $dir     echo -e "\033[4;32mBuilding $dir\033[0m"     npm run build # Some projects use other projects, so build them in series     cd $DIR     echo -e "\n" done   Again, I don't want to continue doing anything in the script if an error occurs at any point, this applies to both the parent and background jobs. Is this possible?

How to wait in a bash script for several subprocesses spawned from that script to finish and return exit code !=0 when any of the subprocesses ends with code !=0 ?  Simple script:  #!/bin/bash for i in `seq 0 9`; do   doCalculations $i & done wait   The above script will wait for all 10 spawned subprocesses, but it will always give exit status 0 (see help wait). How can I modify this script so it will discover exit statuses of spawned subprocesses and return exit code 1 when any of subprocesses ends with code !=0?  Is there any better solution for that than collecting PIDs of the subprocesses, wait for them in order and sum exit statuses?


In situations in which people of different cultures meet, it is people who are unaware of subtle cultural differences can easily find themselves in a situation. Here are two simple examples:   Someone from a culture where people generally smile to passing strangers might assume, when in a foreign land, that the locals do not welcome their visit. A waiter expecting a tip might become angry with a frequently returning foreign customer unfamiliar with the custom.   Within communication studies, cross-cultural studies, or any similar field of study, is there a special term to describe these "situations of misunderstanding" which are brought about not by a language barrier, but by differences in culture, and a mutual lack of understanding of the culture difference by one or more parties involved?  The answers in  do not fit this meaning:   First, they have the connotation that "someone has made a mistake violating the norms of a particular culture", which is not always the case in these situations. Second, I am looking for a term that does not refer to a specific action committed by one person, but by the created situation. Finally, these words do not address the potential mutuality of the situation, but rather, connote blame on one individual.

I am looking for a word or phrase to describe a misinterpretation of tone due to language or cultural differences. For example, this is an answer from , the gaming StackExchange site  Sir it would appear that you have encountered something called a "bug",which is no wonder since DayZ is early access game. This one is known bug and it is even reported on the DayZ feedback site so it will be fixed sooner or later...It doesn't seem to have a high priority for now however. For now reconnecting should fix this problem,sadly it isn't viable long term solution. Here is the link to the ticket if you want to track the progress.  The answer is perfect, explaining not only what is happening, but why it is happening, how to fix it and links to further reading. However explaining  what a 'bug' is in a game seems condescending in any type of gaming community. After further research the poster is from a Middle Eastern country and it seems that he was trying to be verbose in his answer (which should be encouraged) instead of condescending.


How can I find an injective function from $h ∈ (\mathbb N → {0, 1}) → A$. $A = \{f : N → Z|∀n, m ∈ N.(n > m) → (f(n) < f (m))\}$?  I was trying to define it as follows:  $h=-n-f(n)$, but I know that doesn't work since it only maintains $f(n) \leq f (m)$ but not $f(n) < f (m)$.  Would love to hear your thoughts.

I'm trying to think of such an injection, and unfortunately all of those I've thought about are not strictly decreasing. I would love to get some help or clues. Thank you :)


I am trying to understand how the following PC switched mode power supply works :     The way it works in general is OK. What is not clear to me is what is the purpose of the following part in red :     AFAIK :  The main IC (TL494) alternatively open/close Q3 / Q4 transistors. This, in turn, induce current in T2 windings and alternatively open/close Q01 / Q02 transistors. It will connect one end of primary winding of T1 to positive or negative voltage.  When either Q01 or Q02 transistor close, current is forced to go first to the part I have highlighted in red. Why is it so ? What if the primary side of T1 is connected directly to Q01 emitter (instead of having to pass thought T2 red part) ?

I've been experimenting on a lot of half-bridge-based PC PSU schematics. There's one thing I cannot understand:    As can be seen from above, there's an extra winding in series with the high side driving winding (marked with red ?) and one end of it goes directly to the primary of power transformer.  What is its purpose?  Thanks.


I am using the HP Envy x360 15'. Everything works fine but it has an unusually large touchpad (for better Windows 8 usability). Every time I am typing I accidentally am hitting the touchpad and the mouse pointer jumps somewhere else creating chaos during typing.   The solution is to install Touchpad-indicator (as described ) and set the Disable touchpad on typing -option. As far as I understand this uses Sysdaemon which is installed with any Ubuntu installation.   The problem is however that the seconds to wait after the last key press before enabling the touchpad -setting can only be set to 1 or 2 seconds. So far so good, but after using the 1 second setting for days now I have the feeling that my finger falls off as this setting is way too long to be practically usable when working with text.   You can fine-tune Sysdaemon as described . For me, the command syndaemon -i 0.3 -d -K works best, but it does not autostart when I create an entry in Startup Applications. Is there any way to finetune sysdaemon in 15.04 and make it autostart?

I've added the following line into  my startup applications:  /usr/bin/syndaemon -i 0.5 -d -K   but syndaemon is never running when I log in. I always have to execute the command manually from the terminal, at which point it works normally. My other startup applications work fine. This issue occurs in both gnome and unity.  I'm using ubuntu 14.10 (issue occurred in 14.04 as well). I doubt my hardware matters, but I'm on a lenovo yoga 2 pro.  Ideas?


I am trying to time how long a method takes within my application, the issue is that the timing is always showing 0 seconds. What is wrong with my code below?  long currentTimeInMilis = System.currentTimeMillis() % 1000;      public ClassName() {          public void timeMethod() {                  long startOfmethod= currentTimeInMilis;                  methodToTime();                  long endOfMethod= currentTimeInMilis;                  long totalTime = endOfMethod= - startOfmethod;                  LOGGER.info("[Method Took: {}", DurationFormatUtils.formatDuration(totalTime, "H:mm:ss", true) + "]\n");                                                          }     }   The issue is that I'm getting this output every time, eventhough I know it is taking more than zero seconds :  Method took: 0:0:0:

How do you write (and run) a correct micro-benchmark in Java?  I'm looking for some code samples and comments illustrating various things to think about.  Example: Should the benchmark measure time/iteration or iterations/time, and why?  Related:


If  $$y(x-y)^2 = x.$$  Then $$\int \frac{1}{x-3y}  \, dx =? $$  How do I go about doing This?   Just if you want to know the options are in the form of log{(x-y)² + 1}   [This  may not be the answer as this is just one of the options,  Its just to get an idea]   Hints will do.

If y is a function of x such that $y(x-y)^2=x$      Statement-I: $$\int\frac{dx}{x-3y}=\frac12\log[(x-y)^2-1]$$   Because      Statement-II: $$\int\frac{dx}{x-3y}=\log(x-3y)+c$$      Question: Is Statement-I true? Is Statement-II true? Is Statement-II a correct explanation for Statement-I?   I can say that II is false because y is not a constant but indeeed a function, I don't know answers to other two questions.I am thinking that probably we have to eleiminate y from the given functional equation or do a clever substitution?


I have an Ubuntu 13.10 installation, and some I must have removed some Packages or Repositories, so there are some packages which just do not want to install. Namely that is:  SKYPE sudo apt-get install skype-bin  The following packages have unmet dependencies:  skype-bin:i386 : Depends: libqtgui4:i386 (>= 4:4.8.0) but it is not going to be installed               Depends: libqtwebkit4:i386 (>= 2.2~2011week36) but it is not going to be installed               Depends: libx11-6:i386 but it is not going to be installed               Depends: libxext6:i386 but it is not going to be installed               Depends: libxss1:i386 but it is not going to be installed               Depends: libxv1:i386 but it is not going to be installed               Depends: libgl1-mesa-glx:i386 but it is not going to be installed               Recommends: sni-qt:i386 but it is not going to be installed               Recommends: libasound2-plugins:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Than nspluginwrapper  The following packages have unmet dependencies:  nspluginwrapper : Depends: nspluginviewer (= 1.4.4-0ubuntu5) E: Unable to correct problems, you have held broken packages.   And a whole lot of other packages appear if I try to install the shown dependencies. I guess I have delete a whole repository, but how can I figure out which ones are be default in the list?  Thanks in Ahead!  EDIT   is a copy of /etc/apt/sources.list

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


Find the sufficient condition for $l$ and $m$ for which the system of equations  $ab+bc+ca=l$ $abc=m$  has positive integeral solutions for $a,b,c$.  This is not a standard question from some source but I need for some work. I have found some conditions but they are not sufficient, but necessary.

find all  positive integers $a,b,c$ such that  $abc=24$  $ab+bc+ca=38$  If particular values are given then we can easily find the solution but I am searching for some short general method.  Is there any sufficient condition for the constant values to have integer solution?


I have a 13" Late 2012 MacBook Pro which works fine. I am trying to run Hardware test following the instructions in the Apple Support document, , but it is not working.  If I hold the D key while booting, it does not do anything. However, If I hold Option + D and then chose Wi-Fi connection in recovery mode, it shows the following error:  Error: 0x8000000000000003. Cannot Load 'EFI/Drivers/TestSupport.efi'  Status: 0x00000003   There is installed macOS Mojave 10.14.4 over USB today.  Update: The question:       doesn't describe my situation, because in the mentioned case, Option + D works, and no error message is thrown.

I purchased a Late-2011 MacBook Pro 15" used a month ago. At the time of purchase, I successfully ran the .  I've since installed a new SSD and aftermarket RAM. The computer appears to be functioning normally (I'm typing this post on it), but I'd like to run the full hardware test to verify everything is OK.  But I can't seem to get it to load into the hardware test.  I've tried holding down D before pressing the power button on as well as right before the grey screen comes up. I'm confused because I've done this before without any problems.  Is there something obvious I'm doing wrong or is there a way I can check for problems that would stop the AHT from starting?    Additional info by @gentmatt:  The last time I have performed the Apple Hardware Test, my MacBook Pro was running 10.7.2. As of today, I'm running 10.7.3.  The AHT loaded even after I had installed my custom SSD and RAM. But not this time.


$ alias alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"' alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --color=auto' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto'   I was wondering how I can pass the aliases from the shell to a script? Thanks.  $ cat myscript  #!/bin/bash alias  $ ./myscript  $

In my ~/.bashrc file reside two definitions:   commandA, which is an alias to a longer path commandB, which is an alias to a Bash script   I want to process the same file with these two commands, so I wrote the following Bash script:    #!/bin/bash  for file in "$@"     do     commandA $file     commandB $file done   Even after logging out of my session and logging back in, Bash prompts me with command not found errors for both commands when I run this script.  What am I doing wrong?


ubuntu 20.04 used to freeze on boot , after editing grub to "nomodeset" it is working but now i'm unable to change the brightness.

I am unable to adjust brightness levels through Gnome. I had the same issue with 18.04 but it was resolved there (honestly, I can't remember how).  lspci|grep VGA 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18)  xrandr --output LVDS-1 --brightness 0.95 <-- this works through the terminal excerpt from /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"   Thank you in advance.


Prove that $f:[0,\infty) \to \mathbb{R}, x\mapsto x^p$ for $p\geq 1$   is convex.   I tried using this chain of inequalities:$$\frac{f(x_2)-f(x_1)}{x_2-x_1}\leq \frac{f(x_4)-f(x_3)}{x_4-x_3}\leq \frac{f(x_6)-f(x_5)}{x_6-x_5}$$ if $a<x_1<x_2\leq x_3 <x_4 \leq x_5 <x_6<b$. Any Ideas?

Intention  The clear solution is to use the fact that $x^n$ is twice differentiable. But I want a more direct proof. To be clear I want to prove this result without referencing the idea of a derivative.  My work  I decided to start with the inequality I wanted to prove, and work backward to an inequality that is obviously true.  Start with $$(ax+by)^n\leq ax^n+by^n\quad (1)$$  where $a$ and $b$ are positive real numbers such that $a+b=1$. Then (1) can be rewritten as  $$(a-a^n)x^n+(b-b^n)y^n-\bigg(\sum\limits_{k=1}^{n-1}{n\choose k}(ax)^k(by)^{n-k}\bigg)\geq 0$$  I am stuck here.


When i have install ubuntu at that time create admin user, Now my plan is to remove sudo access from this user and added custom sudofile for this user.  First I remove sudo group from this user:  $ sudo cat /etc/group | grep admin admin:x:1000:  $ sudo cat /etc/group | grep sudo sudo:x:27:   Even there is no entry on sudofile :  $ sudo cat /etc/sudoers | grep -v "#" root    ALL=(ALL:ALL) ALL   My custom sudo file :  $ sudo cat /etc/sudoers.d/custom | grep -v "#" Host_Alias HOSTNAME = myhost  Cmnd_Alias ARCH = /bin/tar, /bin/gzip, /bin/gunzip ... ... root ALL = (ALL) ALL admin HOSTNAME = NOPASSWD: ARCH,...,...   Interesting thing is that to prevent service which not define on customsudo file.  $ sudo /etc/init.d/virtualbox status [sudo] password for admin:  Sorry, user admin is not allowed to execute '/etc/init.d/virtualbox   status' as root on myhost.   Issue is that, still  able to edit /etc folder and created another test user which working fine means who can't edit /etc and other operations !  My goal is to privent to edit /etc directory but able to access /var/log/ and other general directory and operation, here we can define service to allow but Can we define the directory and any other way ?

On one particular machine I often need to run sudo commands every now and then. I am fine with entering password on sudo in most of the cases.  However there are three sudo commands I want to run without entering password:   sudo reboot sudo shutdown -r now sudo shutdown -P now   How can I exclude these commands from password protection to sudo?


If matrix A = \begin{bmatrix}3&1\\-2&-1\end{bmatrix}  I am trying to give two specific examples of a non-zero matrix X such that: AX = XA.  so far I let X = \begin{bmatrix}a&b\\c&d\end{bmatrix}  And so AX = XA, and I multiplied X and A respectivley to give the linear equations:  3a + c = 3a - 2b  3b + d = a - b  -2a + c = 3c - 2d  -2b - d = c - d  I believe i am supposed to show this in matrix form and solve the system to get a 4x4 matrix containing expressions with two variables where any number can be substituted so that AX = XA. However I am unsure on how to do this and need some help.

I have a question where I have a matrix $$A=\begin{bmatrix}2&-1\\-1&1\end{bmatrix}$$ and I need to find two examples of a non-zero matrix $X$ such that $AX = XA$. My first matrix is \begin{bmatrix}1&0\\0&1\end{bmatrix} the identity matrix but I cant think of another one. Any ideas?


I keep seeing this: s[::-1] in Python and I don't know what it does.  Sorry if this is a question but I'm new to python and generally programming.

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I came across some scenarios like these:     Case 1: Obviously not true       Q: Why does the sun rise and fall every day?   A: Because the Earth .   A2: Because .     Case 2: Letting the OP do what is declared not to       Q: How can I charge my phone without a charger?   A: Try the USB ports on your computer.   A2: Go buy a charger.    Case 3: Attempt to joke (despite looking like a real answer)       Q: What's this round bird in bright red? [An image]   A: It may be a rare or mutated species of sparrow.   A2: It's a .   A3: It's an .    Should I flag A2/A3 as NAA in those cases?

What is the "Not an Answer" flag and what is its purpose? When should I use this flag? When should I not use this flag? But I'm still not sure if I'm using the flag correctly... An answer is "Not an Answer", but the flag was declined or disputed!   See also:


Which is the appropriate preposition of the word "Alternative "?

I'm wondering whether there is a difference between these two expressions. I never know which one to use. Google seems to return the same amount of results for both, so I suppose there might be a difference.        What are the alternatives for this project?     What are the alternatives to this project?


I am writing this sentence:     I can put you in touch with a business owner in the UK   I'm not sure if I should put "the" for UK or not  Could you help please

I have been taught that it's grammatically proper to use the before countries like "Sudan and Yemen" but I was never given a reason (if there exists any, of course) when I asked why, except for "it is one of those ambiguous parts of English language that we – as non-native speakers – should just accept without trying to look for a reason". Now, I'd like to know if there is any answer to this "why" or I should keep on believing that there are no hard and fast rules when it comes to questions like these.