I want buy a  Macro Reversing Ring for Macro shot but then I can't protect the lens with a filter. Can I use Reverse Protect Ring for lens filter (like UV filer) or lens Cap?

I've started reversing lenses for macro photography and I'm loving it, but something bothers me: a lot of articles say that it exposes the rear element of the lens. Are there protection rings available for the rear element when using a lens this way or do I need to do it myself like this one: ? It seems nice but, even if I like duct tape, using it for something relative to light leaves me uncomfortable...


I'm writing an admin plugin which produces a pop up to give the user a preview of content.    I tried to use thickbox as suggested here -  but it does not respect dimensions.  My questions are - is this just broken, should i go custom, or is there now a better way to do this?  Thanks in advance,   <?php add_thickbox(); ?>  View all";

The iframe in thickbox media library is not big enough to display my custom tab. I tried to add "width=900&height=600" at the end of the link that pointing to the library, but no luck. How can I modify the inframe size?


How to determine sign of $g$?   It is said that we take  it negative if any body is in upward motion. So why we don't take it positive when we observe downward motion.It is very confusing.

I'm a high school student and I'm studying Newton's second Law. While my teacher is calculating a net force of an object he always treat all vectors as positive numbers. I think what he meant is the magnitude of the vector which is always positive, but the problem is that he didn't use the magnitude symbol, for example like $||Fg||$. He said the acceleration due to gravity , g, is positive, but shouldn't it be negative since it is pointing down. This also cause a problem: every time when I calculate the net force I can't add all forces together, instead I need to choose to use minus sign when the vector is pointing down. So in general which way is correct?


I am using Entity Framework Code First to build my database. I have categories which do not change often, but could potentially change in the future. Would it be better practice to store the category data in enums or in an actual table? Below is an example of the ways I would implement the two approaches:  With an enum:  public enum Role {     Administrator, Employee, Developer }  public class User {     public int ID {get;set;}     public string Name { get; set; }     public Role Role { get; set; } }   With a separate table:  public class User {     public int ID { get; set; }     public string Name { get; set; }     public int RoleID { get; set; } // Foreign key to Role table     public virtual Role Role { get; set; } // Navigation property for Role }  public class Role {     public int ID { get; set; }     public string RoleName { get; set; } }

If we have to store the available positions at a company (i.e. Manager, Team Lead, ... etc). What are the best practices for storing it? I have two opinions with comments... "sure, welcoming yours"        Storing it as DB table with columns ID and Name, and deal with it using queries and joins.     Storing it as Enum and forget about the DB table.    In my opinion, I will choose the first solution if I have changing items. So that I won't hard code these options as Enum. I may choose the Enum solution, if I have no doubt that data won't change (for example, Gender: Male, Female).  NOTE: I code in English, and the UI Culture may be Arabic. If I will work with the Enum Solution, I will hard code the culture-based strings in the presentation layer, is it okay from the best practices perspective!!!!  I would like to know your opinions and if my thoughts correspond to what is most recommended "Best Practices"??


Let the polynomial  $f(x)=x^n+a_1 x^{n-1}+a_2 x^{n-2}+.....a_{n-1}x+a_n$ have integral coefficients. If there exists four distinct integers $a,b,c$ and $d$ such that $f(a)=f(b)=f(c)=f(d)=5$ show that there is no integer $k$ such that $f(k)=8$  I have tried to prove it but I somehow feel that my proof is incorrect please point out the errors and suggest some other way to do the question. This how I proceeded  $\frac{x^{n+1}-1}{x-1}=x^n+a_1 x^{n-1}+a_2 x^{n-2}+.....a_{n-1}x+a_n $  $\frac{a^{n+1}-1}{a-1}=5$  hence $\frac{a^{n+1}-1}{5}=a-1$  Since $a$ is an integer $a-1$ will also be an integer hence $5|a^{n+1}-1$  Using fermat's little theorem we know that $a^4-1\equiv_5 0$  Since $f(a)=5$ we get $n+1=4$  Let k be an integer such that $f(k)=8$ $\frac{a^4-1}{8}=a-1$ Since  $a-1$ is an integer $8|a^4-1$   We will consider two cases    when $a$ is an even integer when $ a$ is an odd integer   If $a$ is even then $a^4-1$ will be odd and it not be divisible by $8$  If $a$ is odd then it will be relatively  prime to $8$ hence $8$ will be Carmichael number  $a^7-1\equiv0(mod8)$  which proves that $a^4-1$ is not divisible by 8. $\therefore$ there  is no integer k such that $f(k)=8$

Here's an interesting question I came across.The person who gave it to me told me that it should not take more than $3$ minutes to solve this question. But I could not find any definite solution :( Maybe you guys could give me some help.Any hints would be appreciated.Here's the question:  Let $f(x)$ be a polynomial with integer coefficients. Suppose for $5$ distinct integers $a_i$, $1\le i\le5$, $f(a_i)=2$. Find an integer b (if it exists) such that f(b) = $9$.


I'm using graduated symbology on a vector layer in QGIS and i do not want lines between polygons of the same color. I tried making the border outline transparent, and also setting the border outline to match the fill color and set the border width to 1. I can still see a thin grey border regardless of the settings.   I should add, i'm trying to do this in python. This worked in QGIS but not python:   for actmin, actmax, myLabel, myColor in ranges:     mySymbol = QgsSymbolV2.defaultSymbol(maplayer.geometryType())     mySymbol.setColor(myColor)     mySymbol.setAlpha(myOpacity) mySymbol.symbolLayer(0).setDataDefinedProperty('color_border','color_rgba'+str(rgbacolors[i]))           myRange = QgsRendererRangeV2(actmin, actmax, mySymbol, myLabel)         myRangeList.append(myRange)         i+=1  myRenderer = QgsGraduatedSymbolRendererV2('', myRangeList) myRenderer.setMode(QgsGraduatedSymbolRendererV2.Quantile) myRenderer.setClassAttribute(mappingcol) maplayer.setRendererV2(myRenderer)

I have a GML layer representing an hexagonal grid that I would like to include in some maps. In QGIS (version 2.14.2) I applied a graduated style and completely removed the polygon border:    However, in the map canvas the borders are still being portrayed:    Zooming in one can see the border around each polygon, it is thin, but it is still there:    Suspecting this was an issue with the map canvas itself, I tried to produce some maps with the Print Composer. Even in vector format the polygon borders are portrayed. Please check these files:       Is there any way to force QGIS to remove these borders?


I was just playing with logarithms and factorials, and then realized that $f(x) = \frac{\ln (x!)}{\ln(x)}$ is slower than $f(x) = x$. From there I got $\frac{\ln x!}{(x \ln (x))}$. In most calculators, I can't find the limit, and when I put a ridiculously large number it doesn't go below 0.6. So is the limit 0?

I can't seem to find a good way to solve this.  I tried using L'Hopitals, but the derivative of $\log(n!)$ is really ugly. I know that the answer is 1, but I do not know why the answer is one.  Any simple way to go about this?


For the following query  SELECT sum(c)  FROM (SELECT 1 c WHERE false) t;   I thought it takes the sum of zero numbers, and therefore should return 0. (Similarly, I expect, e.g. an array aggregate function to return an empty array on zero elements).  Yet, it is returning a NULL (using PostgreSQL 11).  => SELECT sum(c) FROM (SELECT 1 c WHERE false) t;   sum  -----  (1 row)   This doesn't make sense to me logically.   Why is the sum of zero numbers (for any numeric type) not zero? Is this NULL returning behavior standard?  Or maybe I am missing something. Any reason one has to make the sum NULL in some corner cases?

The  (chapter 6.5, set function specification) the following behaviour for aggregate functions on empty result sets:  COUNT(...) = 0 AVG(...) = NULL MIN(...) = NULL MAX(...) = NULL SUM(...) = NULL   Returning NULL for AVG, MIN and MAX makes perfect sense, since the average, minimum and maximum of an empty set is undefined.  The last one, however, bothers me: Mathematically, the SUM of an empty set is well-defined: 0. Using 0, the  of addition, as the base case makes everything consistent:  SUM({})        = 0    = 0 SUM({5})       = 5    = 0 + 5 SUM({5, 3})    = 8    = 0 + 5 + 3 SUM({5, NULL}) = NULL = 0 + 5 + NULL   Defining SUM({}) as null basically makes "no rows" a special case that does not fit in with the others:  SUM({})     = NULL  = NULL SUM({5})    = 5    != NULL + 5 (= NULL) SUM({5, 3}) = 8    != NULL + 5 + 3 (= NULL)   Is there some obvious advantage of the choice that was made (SUM being NULL) that I have missed?


I know I can compare  $\sum_{n \leq x}1/n$ with $log(x).$ I also think $log(x) \leq\sum_{n \leq x}1/n.$

Consider the partial sum of the divergent Harmonic series $H_n = \sum\limits_{k = 1}^{n}\frac{1}{k}$. I recently saw a question which required finding out the asymptotic bounds of $H_n$. Now, I could not find any bound closer than $O(n)$. So I looked up the series and found  Wikipedia article which says that $H_n - \ln n$ approaches a constant (the ). This clearly shows that $H_n = \Theta(\log n)$.  However, considering the question was in an beginners undergraduate algorithms course in CS, I was wondering if there is a simpler proof of this? Is there some clever proof requiring elementary mathematics to show $H_n = \Theta(\log n)$?  PS: This is not homework in the sense that it is not my homework, and the actual question does not ask for a proof, but rather asks a lot of functions to be arranged asymptotically.


Where do I set the Stack Exchange clock for my time zone? I live in the  (ET), Daylight Savings or Summer Time. At 11:00 each night (UTC 3:00, according to the notice at the top), the records for my reputation points switch over to a new day, as though my clock is set for a time zone further east. Is there a way for me to change this in my account settings? I think my time zone is UTC -5 by some standards. I am unable to find my primary account with settings, name, email, etc. I never log out. I guess I'm lost.

Is my local time considered in the daily reputation points cap, or number of votes?


i am getting this type of problem,when i open my computer(continue to wait or press s to skip mounting or m for manual recovery)  please help me regarding this

After upgrading my laptop from karmic to lucid, my fat32 partition won't mount automatically. I get the message:  The disk drive for /osshare is not ready yet or not present Continue to wait; or Press S to skip mounting or M for manual recovery   Funny thing is, if I skip, then /osshare/ is mounted once I log in.   I've a similar setup on my desktop, and it works fine. Fstab on desktop:  UUID=4663-6853  /osshare        vfat    utf8,umask=007,gid=46 0       1   /etc/fstab on laptop:  UUID=1234-5678 /osshare vfat utf8,auto,rw,user 0 0


I have spent quite a few hours researching how to do this, but still cannot understand how to add a missing .sty file on my linux mint machine.   I have installed texlive by:  sudo apt install texlive-latex-base   I then tried to compile my .tex document:  pdflatex filename.tex   I got the error message that the endfloat.sty is missing.  So I tried to install it, by first trying to find where my sty files are:  whereis texlive   which returns /usr/share/texlive , then after a bit of searching I found the other .sty files are in their own directories within /usr/share/texlive/texmf-dist/tex/latex.  I tried to make a path then to put my missing .sty file in using the sudo command:  sudo mkdir endfloat   which made the directory   /usr/share/texlive/texmf-dist/tex/latex/endfloat   I changed into that directory, and then did   sudo wget https://mirror.hmc.edu/ctan/obsolete/macros/latex209/contrib/misc/endfloat.sty   But when I reran:  pdflatex filename.tex   Still it did not compile because it says the .sty file is missing.

I need to install a new TeX/LaTeX/ConTeXt package on my computer.  I'm running Ubuntu/Fedora/Slackware/Some-Version-Of Linux.  What are the possible ways to do this?    Note:   We get a number of questions that essentially reduce to this one; it was felt a good idea to have one question-and-answer that can cover all the standard methods.  See  for the discussion.  The question-and-answer are CW so that more information can be easily added.  If you have information to add, please do so.  If you are unsure, leave a comment here or (preferably) in .  Comments on the question and answer will be periodically removed to ensure that the information is clear.


I'm assuming questions about the third law being invalid in relativity have already been asked on this site, but I'm specifically asking about how momentum is still conserved inspite of it. Consider only two particles in the universe. In some reference frame, they're moving with velocities $v_1(t)$ and $v_2(t)$ at time $t$. The relativistic momentum is: $$\gamma (v_1(t))m_1v_1(t)+\gamma (v_2(t))m_2v_2(t)$$ The relativistic momentum after a small time $dt$ is: $$\gamma (v_1(t+dt))m_1v_1(t+dt)+\gamma (v_2(t+dt))m_2v_2(t+dt)$$ If both these quantities are same, we can set them equal. After setting them equal, we get: $$\gamma (v_1(t+dt))m_1v_1(t+dt)-\gamma (v_1(t))m_1v_1(t)=-(\gamma (v_2(t+dt))m_2v_2(t+dt)-\gamma (v_2(t))m_2v_2(t))$$ Dividing both sides by $dt$ and letting $dt\rightarrow 0$, we get: $$\frac{d(\gamma(v_1(t))m_1v_1(t))}{dt}=-\frac{d(\gamma(v_2(t))m_2v_2(t))}{dt}$$ $$F_{12}=-F_{21}$$ So what's wrong with the above? Edit- That other question is about General Relativity and the answers do not address the computations I've provided here. I want to know what's wrong with this specifically Edit- After reading the other links, what I got is that the momentum conservation, as I've stated stated it in this post, is incorrect. This is because I did not account for the momentum of the field. So that means that Newton's third law is also correct if we extend the notion of force from particle-particle interactions to particle-field interactions. Is this correct? And in what sense do fields carry momentum? What is the mass and velocity of fields?

Is Newton's third law valid at the General Relativity?  Newton's second law, the force exerted by body 2 on body 1 is: $$F_{12}$$ The force exerted by body 1 on body 2 is: $$F_{21}$$  According to Newton's third law, the force that body 2 exerts on body 1 is equal and opposite to the force that body 1 exerts on body 2: $$F_{12}=-F_{21}$$


Let $a\in \mathbb{R}$, $a\neq 0$, and $E=\{(x,y,z)\in \mathbb{R}^3:a+x+y+z\neq 0\}$ and $f:E\rightarrow \mathbb{R}^3$ defined by  $$ f(x,y,z)= \left( \frac{x}{a+x+y+z}, \frac{y}{a+x+y+z}, \frac{z}{a+x+y+z} \right).$$  Compute the inverse of $f$.    I know I can use the Inverse Function Theorem to show local invertibility, however, that does not necessarily imply global invertibility. Thus, even though I can invert the Jacobian of the function, it does not follow that I can recover the inverse function from its Jacobian. Therefore, I have no idea what to try for this problem. Could you please provided a small hint on something to try for this problem? Thank you in advance.

Let $a\in \mathbb{R}$, $a\neq 0$, and $E=\{(x,y,z)\in \mathbb{R}^3:a+x+y+z\neq 0\}$ and $f:E\rightarrow \mathbb{R}^3$ defined by $$ f(x,y,z)=\big(\frac{x}{a+x+y+z}, \frac{y}{a+x+y+z}, \frac{z}{a+x+y+z} \big) $$ Show that $f$ is injective.    I've been trying to prove it directly by showing that if $f(x_1,y_1,z_1)=f(x_2,y_2,z_2)\Rightarrow$ $x_1=x_2, y_1=y_2,z_1=z_2$. But I get a system of equations which I'm find difficult to deal with. Any help would be greatly appreciated.


So for some reason I have caught, like, a dozen Pidgey's. I have mostly been handing them over to the professor and have a good supply of Pidgey candy. I also have one Pidgey with relatively high CP that I've powered up a few times with stardust. I see from the arc around it that it looks like there's a maximum value to powering it up. I also have the option to make it evolve right now.  Is there a reason to power up a Pokemon before evolving them (or vice versa?) what's the best practice here?

When activating the evolution for a caught Pokemon, it seems to amplify the Combat Power (CP). Thus it seems most beneficial to evolve your Pokemon with the highest CP, if you have multiple of the same kind.   But what I am not sure about is whether it makes an efficiency difference if you spend candies and dust to boost CP before evolving, to gain more from the amplification? Or is it more efficient to just evolve without spending, and then using the leftover candies afterwards, since they now give a bigger CP boost per candy?   I only tested with a Rattata so far, which gained +8 CP per candy before evolving, and +15 CP afterwards. I collected no numbers on the amplification efficiency though, and now ran out of materials for further testing.  Or maybe it is a balanced calculation and makes no difference at all? I would love to have some insight on that.    Some data I collected thus far: (GPC = CP gain per candy)  79 CP Weedle (GPC 6) evolved to: 84 CP Kakuna (GPC 6), evolved at 90 CP to: 297 CP Beedrill    Note: The max-CP "half circle" in the profile stayed filled roughly at the same relative position throughout the evolutions.


I am currently setting up puppet for a network of around 30 servers in a master / agent setup, but since I am using the open source version of puppet, is there really any advantage of using a puppetmaster?   I have to ssh to the server to set up the puppet agent anyway, so why not setting up a cronjob that pulls directly from github (a 'release branch' maybe?) and applies certificates directly seems also very attractive.   Are there any significant advantages of using a open source puppetmaster? Since puppet kick got deprecated, I can't think of any that come out of the box.

We have around 300 RHEL servers that are currently connecting to a Puppetmaster server.  However, we have noticed some performance bottlenecks and it is the point of failure in our system.  I am fairly new to puppet in general and I am considering creating a decentralized puppet architecture instead of having Puppet clients connect to the Puppetmaster server.  Aside from what I would suspect to happen such as performance gain and lack of signing and exchanging SSL certs for new machines, what are other pros and cons to setting up a decentralized architecture?


I'm trying to convert a string into a double but my double gets cut off at the 3rd decimal point.  My string looks like this: "-122.39381636393" After it gets converted it looks like this: -122.394  void setLongitude(string longitude){     this->longitude = (double)atof(longitude.c_str());      cout << "got longitude: " << longitude << endl;     cout << "setting longitude: " << this->longitude << endl; }   Output example:   got longitude: -122.39381636393 setting longitude: -122.394   I want it to maintain all the decimal points, any tips?

In my  I was printing a double using cout that got rounded when I wasn't expecting it.  How can I make cout print a double using full precision?


Most of the objects in space are likely to have an atmosphere. Since space is void, the gases in atmosphere should have either dissolved or emptied into space. But, some of the objects still seem to be revolving with their atmosphere. I'm curious why the molecules can't just escape into space?

People said outside earth is a vacuum.  But the air does not get sucked from the  Earth's surface. Some said it is due to gravity and some said the speed of air molecules are not high enough to escape.  We know vacuum will suck air like your vacuum cleaner and it has nothing to do with gravity. If outer space is really a vacuum, what prevents air escape the earth?


I am just starting with Java and I have a baffling problem. I have a short piece of code, and somehow my IF statement is skipped over. Here it is:  import java.util.Scanner;  public class helloworld {  private static Scanner s;  public static void main(String[] args) {      s = new Scanner(System.in);      //Question what's your name + validation         System.out.println("Hello guy, What's your name?");         String name = s.nextLine();         System.out.println("Are you ok for " + name + "? (answer by yes or no)");          String ok = s.nextLine();  // capture ok response and print to screen to show that value is read         System.out.println(ok);   // below is ignored!                 if(ok=="no")                 {                 System.out.println("What do you mean? You don't know your name? Bye!");                 }                  if(ok=="yes")                 {                 System.out.println("thank's " + name + "I have a question...");                     System.out.println("Is my first program good?");                         String goods = s.nextLine();                                 //validation question programme                             if(goods=="no")                             {                                 System.out.println("so i will update my performance!");                             }                             if(goods=="yes")                             {                                 System.out.println("thank you for your answer guy! ;-)");     }                }                    } }   Even when I reply "no" , the IF statement is not executed, but the response is captured and shown on screen; Can someone help me with that IF statement,  Thanks!  T

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


Since for about an year  but the  still mentions "Featured" tab:  The bountied question will appear with a special indicator in all question lists, and it will also be visible on the  for 7 days.

The "Featured" tab on the homepage .  However, the  still refers to it as the "Featured" tab:     The bountied question will appear with a special indicator in all question lists, and it will also be visible on the homepage Featured tab for 7 days.   Also, as Arulkumar commented, the  also refers to it by its old name:     The question gets placed in the home page's featured tab for seven days.   Can these both please be changed to "Bountied" to match the new name of the tab?


I tried to mount an external HDD but, It seems that there's no partition in there.  fdisk -l   shows that     Disk /dev/sda: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors   but there's no /dev/sda1 or sda2 etc.  Could you tell me CLI command for making it to /dev/sda1 as a whole?  Thanks!

I want to know how to format a storage drive from the terminal. Helpful things to provide in the answer would be often used options for commands and base knowledge that one can use to extrapolate future uses. Specifically I would like to know how to format in the different file systems such as NTFS, FAT32, EXT4, etc. Information on how to partition the drive via terminal is also wanted.  I am trying to format a high capacity external hard drive (EHDD) into NTFS - from the terminal.   I know I can use gparted for this as well as other GUI programs, but I still want to now how to do it from the terminal.


I've just realised that the Quorum badge does not show up in "Choose which badge to track",    in any of the three cases:   You have made no progress at all; You have a Meta quetion with one vote (50% progress) You have been awarded it.     Is there any design reason for this?    Note that this question seems to me to be different from .

The  badge seems like a great candidate for a trackable badge: it requires doing a thing multiple times, there aren't any other requirements to get it, and it is (seems?) quite easy to determine how many times the thing has been done.  But Convention does not appear in the list of badges that can be tracked. I would like to be able to see a quick count of my well-received meta posts without going to my meta user activity page and poking around.


In Chapter 10 of Harry Potter and the Goblet of Fire, Ginny mends her schoolbook with Spellotape:     "Why are they all sending Howlers?" asked Ginny, who was mending her   copy of One Thousand Magical Herbs and Fungi with Spellotape on the   rug in front of the living room fire.   Wouldn't it be quicker and cleaner if for example Molly just mended it with the Reparo spell?

I've found reasons on this site for Lupin's battered 'Professor' briefcase even though he hadn't taught before, but are the descriptions of his clothes an inconsistency? Can wizards not fix clothing even though a child can fix a pair of spectacles and another has a good crack at fixing a nose? Perhaps Lupin isn't quite as embarrassed about his condition as we think and is crying out for help?   Slughorn's clothes are similarly described to show his fall from glory or decline into old age.  Apart from the characterisation, is there a reason that wizards can't fix clothes, or is there an alternative explanation?


EDIT: My question is a duplicate but my answer here is a bit different than the answer in the linked duplicate above.  I cannot install, remove, or upgrade anything using APT because of this error:  $ sudo apt-get upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not installed             Recommends: uvcdynctrl but it is not installed E: Unmet dependencies. Try using -f.   I'm certain I can find and fix this error. I'm more interested in knowing why the entirety of apt is broken because of one program having a problem.  Edit: I can't apt-get dist-upgrade either:  $ sudo apt-get dist-upgrade Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not installed             Recommends: uvcdynctrl but it is not installed E: Unmet dependencies. Try using -f.   apt-get -f install is met with this error:  Preparing to unpack .../libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb ... Unpacking libguvcview-2.0-0:amd64 (2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1) ... dpkg: error processing archive /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb (--unpack):  trying to overwrite '/usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0', which is also in package libguvcview-2.0-2:amd64 2.0.4+debian-1 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing:  /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   It should be noted that the file /usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0 does not exist on my system.  I can't do anything with APT because of this. I can't even remove an unrelated program. abiword is a text editor.  $ sudo apt-get remove abiword Reading package lists... Done Building dependency tree        Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies:  guvcview : Depends: libguvcview-2.0-0 but it is not going to be installed             Recommends: uvcdynctrl but it is not going to be installed  lubuntu-desktop : Depends: abiword but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   OS: Lubuntu desktop (Ubuntu 16.10)

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?


After translating in pdflatex  \documentclass[12pt]{article}  \pagestyle{empty}   %  no page number  \begin{document}  \title{Article name} \author{Author}  \maketitle  \end{document}   the first page is numbered.  How do I remove the numbering? Or is there another tool for having no page numbers?

In the LaTeX document pasted below, I still see page numbers upon compiling, even though I've included a \pagestyle{empty} command below the \maketitle command. Any ideas what I'm doing wrong? Thanks in advance.  \title{Thesis Abstracts} \author{         Kurt Han Peek } \date{\today}  \documentclass[a4paper,11pt]{article} \usepackage{graphicx} \usepackage[margin=2cm]{geometry}  \begin{document} \maketitle \pagestyle{empty}  \section*{An Analysis of the Effects of Digital Phase Errors on the Performance of a FMCW-Doppler Radar} In modern frequency-modulated continuous-wave (FMCW) radars, the transmitter is increasingly being implemented using direct digital chirp synthesis (DDCS), which provides improvements in sweep linearity, stability, precision, agility, and versatility over analog techniques. Its main limitations are errors due to sampling of the modulating signal, phase truncation, and digital-to-analog converter (DAC) quantization, which produce spurious signals due to their deterministic nature. This thesis presents an analysis and simulation of the effect of two sources of digital phase errors -- namely, sampling of the modulating signal and phase truncation -- on the performance of a FMCW-Doppler transceiver employing a DDCS in its transmitter. An upper bound for the amplitude of spurious targets resulting from these digital phase errors is established. Further, it is shown that provided the phase errors are periodic with the sweep period, the spurious targets are not offset from the target in Doppler. An algorithm for selecting the digital chirp parameters of a DDCS so as to ensure periodic and phase-continuous sweep transitions, which guarantee periodic phase errors and reduce `spectral splatter', is devised. Finally, we investigate parallels of FMCW radar in the optical domain, and consider the fundamental question whether range resolution is fundamentally limited by the bandwidth of a transmitted signal, or its carrier frequency.  \section*{Estimation and Compensation of Frequency Sweep Nonlinearity in FMCW radar} One of the main issues limiting the range resolution of linear frequency-modulated continuous-wave (FMCW) radars is nonlinearity of frequency sweep, which results in degradation of contrast and range resolution, especially at long ranges. Two novel, slightly different, methods to correct for frequency sweep nonlinearity by digital post-processing of the deramped signal were introduced independently by Burgos-Garcia et al. (Burgos-Garcia, Castillo et al. 2003) and Meta et al. (Meta, Hoogeboom et al. 2006). In these publications, however, no formal proof of the techniques was given, and no limitations were described. In this thesis, we prove that the algorithm of Meta is exact for temporally infinite chirps, and remains valid for finite chirps with time-bandwidth products which are large compared to unity, provided the maximum frequency component of the phase error function is small compared to the square root of the nominal chirp rate. It is also shown that the algorithm of Meta reduces to that of Burgos-Garcia in this limit. A digital implementation of both methods described. Finally, we propose a novel method to measure the systematic phase errors which are required as input to the compensation algorithm.  \end{document}


Well, a friend of mine sent me this picture of an creepy insect. I'm wondering if the picture is photoshoped or if it is real. It is said the insect lives in Indonesia, but I'm not sure.    Can anyone identify this? Thanks.


Context: I run a photography business that encourages people sharing photos without restrictions. My websites contains galleries of thumbnail images where each image links to the original, high-res version. For example, a gallery page may look like this:  The webpage uses  that switches the browser to full screen mode when the user left-clicks an image, showing the full resolution version of the image. This all works nicely both for viewing and downloading images. Users can simply right-click the high-res version and select "Save Image As..." from the context menu. Alternatively, they can right-click the thumbnail image and select "Save Link As..." to accomplish the same thing. However, I recently found out that some users attempt to download images by right-clicking the thumbnail image and selecting "Save Image As...", which results in downloading a low resolution version rather than the original image. This has resulted in my photos being shared and displayed by others in low resolution, something which they did not intend to do. How can I improve the UX of my photography website to prevent users downloading low resolution images?

As part of our system, a web application, we have an image viewer. Previously we always displayed the full resolution image but scaled down with CSS to fit the page. For performance reasons we now display a properly scaled version of the image with the option to download the full resolution image with a button under the image.  As part of the users' workflow, they sometimes need to download this full resolution image to submit to another system. The problem is that many users just right-click the image and press "save image as". This used to work fine but now it will instead provide them with a low resolution image. The users don't notice this and this causes problems further down the line. How can we force users away from this behaviour? Sure, we could tell them not to do it but that doesn't feel very scalable. My least bad idea so far is to hijack the right-click in the browser but this is A) not super nice UI and B) not sure to cover all cases.  In short: How can we get users to use the download button instead of saving the low-res thumbnail?


I request a top ( ^ ) link to be available on the bottom (near paging links) only  on Mobile site. It will be used when scroll down until last question in page. It'll be useful mainly when loading 50 per page. This isn't a duplicate for  which is about adding it to left navigation bar This isn't an exact duplicate for  which is about adding it on browser, becauase my main issue is on mobile browsing

The left-nav is great - I like it, users who don't can disable it. Perfect world. Now it's stickied it's always there too, which is really useful.  When I'm navigating in areas not directly linked to in the left nav and have scrolled down, I often want to re-use the other navigation. This means scrolling up. Which is fine, of course it's how websites work.  However, if the left-nav had a "Top" link which took the user to the very top of the page it would be great for getting back to specific contextual menus and things that are not linked to in the left-nav.  For example, if I'm viewing questions on a specific tag and I've scrolled down, I sometimes want to get back up to the top to remove a tag, or change from "Latest" to "Featured" etc. Although clicking the "Questions" link in the left-nav takes me back to the top, it removes the tag(s) I was searching with.  There are other use cases where this would be useful, like long questions and answers (Etc). So I think a "Top" link in the left nav would be very useful.    I think this is different to the  as it doesn't mention the left-nav, and my question is suggesting this idea because we have a good place to put it and it'll be a useful addition to the left-nav.


I have a Dictionary<string,object> where I save objects to parse to my plugin system, some of these objects need to be a copy not the original so I use this DeepClone method: public static T DeepCloneJSON<T>(this T Obj)         {             var text = JsonSerializer.Serialize(Obj);             return JsonSerializer.Deserialize<T>(text);         }  for example, if I do : var dict = new Dictionary<string,object>(){     {"someKey",new List<MyClass>(){new MyClass()}} } var copy = dict["someKey"].DeepCloneJSON(); var cast = (List<MyClass>)copy;  i get a System.InvalidCastException, but if i use a MemoryStream DeepCopy method i don't get this exception, like this one: public static T DeepCloneMemoryStream<T>(this T obj)         {             using (var ms = new MemoryStream())             {                 var formatter = new BinaryFormatter();                 formatter.Serialize(ms, obj);                 ms.Position = 0;                  return (T)formatter.Deserialize(ms);             }         }  so, I would like to know why I get this exception using a System.text.json based DeepClone Method and if it is possible to do this with a System.text.json because in my tests it presents to be faster and use less memory than a MemoryStream based onde.

I want to do something like:  MyObject myObj = GetMyObj(); // Create and fill a new object MyObject newObj = myObj.Clone();   And then make changes to the new object that are not reflected in the original object.  I don't often need this functionality, so when it's been necessary, I've resorted to creating a new object and then copying each property individually, but it always leaves me with the feeling that there is a better or more elegant way of handling the situation.  How can I clone or deep copy an object so that the cloned object can be modified without any changes being reflected in the original object?


For evaluating $\sum^n_{k=0}{n\choose{k}}{m\choose{k}}$ for fixed $m,n$, I got ${n+m\choose{n}}$, does it look right?  I rewrite it as $\sum^n_{k=0}{n\choose{n-k}}{m\choose{k}}$, that's what I did.

How do I evaluate $\sum_{k=0}^{n} {n \choose k}{m \choose k}$ for a given $n$ and $m$.  I have tried to use binomial expansion and combine factorials, but I have gotten nowhere. I don't really know how to start this problem.  The answer is ${n+m \choose n}$. Any help is greatly appreciated.  EDIT: I'm looking for  a proof of this identity.


I am reading paper about  of electrons, which can exhibit famous Majorana fermions at ends of wire. The Hamiltonian (his Eq. (6)) reads  $H = \frac{i}{2} \sum_j - \mu c_{2j-1}c_{2j} +(w+|\Delta|)c_{2j}c_{2j+1} +(-w+|\Delta|)c_{2j-1}c_{2j+2}$  in terms of the Majorana operators $c_{2j-1}$ and  $c_{2j}$. The symbols $\mu, w, |\Delta|$ can be thought of as parameters controlling Fermi level, hopping and gap.  Kitaev shows there are solutions of Hamiltonian $H$ with zero-energy. He  gives the operators associated to zero-energy solutions in ansatz form (his Eq. (14)):  $b' = \sum_j \left( \alpha_{+}' x_{+}^{j} + \alpha_{-}' x_{-}^{j}\right) c_{2j-1}$  $b'' = \sum_j \left( \alpha_{+}'' x_{+}^{-j} + \alpha_{-}'' x_{-}^{-j}\right) c_{2j}$  where all $\alpha$ are constants and $x_{\pm}$ are unknowns to be found.  Q1) How to find $x_{\pm}$?  Q2) How to show $x_{\pm} = \frac{-\mu \pm \sqrt{\mu^2 - 4 w^2 + 4 |\Delta|^2}}{2 (w+|\Delta|)}$?  I attempted to show it by computing $[b', H]=[b'', H]=0$, but it did not give correct answer.  Any help appreciated.  (Full disclosure: this is reworded version of )

I am reading paper about  of electrons, which can exhibit famous Majorana fermions at ends of wire. The Hamiltonian (his Eq. (6)) reads  $H = \frac{i}{2} \sum_j - \mu c_{2j-1}c_{2j} +(w+|\Delta|)c_{2j}c_{2j+1} +(-w+|\Delta|)c_{2j-1}c_{2j+2}$  in terms of the Majorana operators $c_{2j-1}$ and  $c_{2j}$ and constants $\mu, w, |\Delta|$ can be thought of as parameters controlling Fermi level, hopping and gap.  Kitaev shows there are solutions of Hamiltonian $H$ with zero-energy. He  gives the operators associated to zero-energy solutions in ansatz form (his Eq. (14)):  $b' = \sum_j \left( \alpha_{+}' x_{+}^{j} + \alpha_{-}' x_{-}^{j}\right) c_{2j-1}$  $b'' = \sum_j \left( \alpha_{+}'' x_{+}^{-j} + \alpha_{-}'' x_{-}^{-j}\right) c_{2j}$  where all $\alpha$ are constants and $x_{\pm}$ are unknowns to be found.  Q1) How to find $x_{\pm}$?  Q2) How to show $x_{\pm} = \frac{-\mu \pm \sqrt{\mu^2 - 4 w^2 + 4 |\Delta|^2}}{2 (w+|\Delta|)}$?  I attempted to show it by computing $[b', H]=[b'', H]=0$, but it did not give correct answer.  Any help appreciated.


I remember watching a scifi series when I was growing up - it was either in the late 80s or early 90s that I watched it.  These are elements I can recall   The world was polluted or contaminated somehow There were humans living in communities of a sort that had a higher level of technology that had cleaner air The humans out in the polluted areas were more Mad Max-like and I think were mutated somehow or other The 2 human elements were not friendly towards each other and there was a fair bit of conflict between them Some of the cast for the humans in the community were more militarized and would go out to try and help people or to do repairs and such I think that the terrain was more desert like for the most case   I don't remember much beyond these aside from the fact that I enjoyed the show.  Does anybody recall the name of this show?  I think that it was more serious than comedy, but I'm remembering from a child's perspective.

I'm trying to figure out the name of a movie I saw on TV as a kid, in the mid-to-late 90s, in the US, in English, on daytime TV.  I remember it being kind of Starship Troopers-esque, but everyone had these glowing lights in their chests.  They glowed in different colored patterns, and I think it had something to do with whether you were attracted to someone or not (I was probably like 7 when I saw it, I didn't really understand the context of that part yet).


As clearly defined in Life After People Nuclear Power plants would melt down days to weeks after people disappeared. Now, I seriously doubt that anybody would stick around to even try to operate the reactors when the crap hit the fan......so since America alone has over 100 reactors so in theory the good old USA should be a desolate, radioactive death-zone ass well as filled with the undead. Also why didn't the huge chemical spills that would have occurred after and during the panic effect the survivors at all?  My question is this: Why didn't the world become totally inhospitable after the mass outbreaks.

Since there is no electricity, wouldn't all the nuclear reactors around the country be down and already released radiation into the air? Why is there no sign of this?


A single radioactive nucleus has a constant probability to decay at any moment. Does this imply that the decay of the particle has a uniform probability distribution from the point in time of the particle's creation to a point infinitely far away in the future?   If this is the case, how is this possible if it is not possible to have a uniform probability distribution over an infinite domain (for example, over the whole number line)?

In my curriculum, the  is "the probability of decay per unit time"  To me, this seems non-sensical, as the decay constant can be greater than one, which would imply that a particle has a probability of decaying in a time span that is greater than 1.  Can someone explain this?


Consider the sentence:      I don't seem to have enough time.   Theoretically, it could be rephrased:     I seem to not have enough time.   It seems to be grammatically correct, but it sounds a bit off. What is the problem with the rephrased version?

Are the following sentences correct?     He seems not to want to help us   and         He seems want to help us.   Is it correct if I use "seem" in a negative sentence? Which role does "seem" play?  Is there any difference in meaning between:    It seems not working for me.   It doesn't seem work for me.  It seems not to be working.   Please tell me the differences between the three of them and in which situation I can use them.


I have ubuntu 13.10 installed and I'm still very new to this. I'm still trying to grasp the system mechanics so I would like a step by step solution.  I've downloaded and installed wine 1.5 with winetricks. Using winetricks I installed Steam successfully. When I run Steam the login screen comes up fine. The problem appears after typing in my info and logging in. It just closes, with nothing appearing.  Anyone have any tips?

I am looking for a step by step instruction to guide me in the ways of installing, configuring and debugging many of the issues new users have when dealing with Wine in Ubuntu.  What is the recommended way of installing Wine, some of the key issues that it has and how to solve them?  If I have a specific problem with an App in Wine, how do I go about solving it? What are the recommended steps to ensure that I can fix a problem related to an app I wish to use?


I'm in the market for a lens I can use for portrait photography as well as nature. I hate background blur. The portrait photography I do and get a great response from, are the ones where I frame the subject myself.   What type of lens, for a reasonable price, can I get that will not blur the background, yet still provide great quality photos?  At the moment, I own a Nikon Coolpix p510. I plan to buy a camera after I pick out the lens to get the best results. I'm fine with slight blur while the focus is on the main subject, but I have noticed while looking at portrait lenses, most remove background details all together.

I am quite new to DSLRs and one of the first things I noticed was the incredible focus points and appearance of depth that you can achieve. That is great in a lot of scenarios, but not in all. When filming a landscape as a whole, I do not want to have the focus on that single tree, but on the whole skyline.  Is there a way by which you can sort-of "disable" the focus, so that the raw image is recorded without any added blur? I suppose something as simple as this is only a small function you can turn off, but I can't seem to find it in the manual of my camera.


f: $\mathbb{R}$ $\to$ $\mathbb{R}$ is a continuous function and $\overline{f(\mathbb{N})} = \mathbb{R}$. Prove that f is surjective. I've thought alot about this but i still haven't find a clue. I would really appreciate any help or a hint.

Let $f:\mathbb{R}\to \mathbb{R}$ be a continuous map such that $\overline{f(\mathbb{N})} = \mathbb{R}$. Prove that $f$ is surjective.  I tried to use the definition of the continuity and $\overline{f(\mathbb{N})} = \mathbb{R}$ to show that $f$ is surjective but it didn't work. Since $f$ is continuous, the preimage of every open set is open. Also it results in $f(\overline{A})\subseteq \overline{f(A)}$ for every set $A$. How this couples with $\overline{f(\mathbb{N})} = \mathbb{R}$ to show surjectivity?


From the uncertainty relation it follows that:  $$\Delta E \ \Delta t = \hbar$$  $\Delta E$ is the energy uncertainty of a state, $\Delta t$ should be the  uncertainty of the lifetime $\tau_b$ of the state. I don't understand why $\Delta t$ is usually confounded with the lifetime itself, $\tau_b$ and the relation written as  $$\Delta E \ \tau_b = \hbar$$

In non-relativistic QM, the $\Delta E$ in the time-energy uncertainty principle is the limiting standard deviation of the set of energy measurements of $n$ identically prepared systems as $n$ goes to infinity. What does the $\Delta t$ mean, since $t$ is not even an observable?


I'm having trouble getting this to vertically align automatically. I know I can add a padding-bottom to center it manually, but I'd rather it position vertically automatically. How would I go about doing this? And I need to keep the display: inline-block functionality.

title

                  text for paragraph goes here

What is the best way to vertically center the content of a div when the height of the content is variable.  In my particular case, the height of the container div is fixed, but it would be great if there were a solution that would work in cases where the container has a variable height as well. Also, I would love a solution with no, or very little use of CSS hacks and/or non-semantic markup.


The questions specifies that EF cannot equal 0. I was just wondering if there was an intuitive way to find an example of this relationship, without having to define each matrix, multiply them out and come up with a few conditions that need to be satisified. Could eiegenvectors and eigenvalues be used? Thanks

The Problem Let $A$ be the matrix $\bigl(\begin{smallmatrix}a&b\\c&d\end{smallmatrix} \bigr)$, where no one of $a,b,c,d$ is $0$. Let $B$ be a $2\times 2$ matrix such that $AB+BA=\bigl(\begin{smallmatrix} 0&0\\ 0&0 \end{smallmatrix} \bigr)$. Show that either   $a+d=0$, in which case the general solution for $B$ depends on 2 parameters, or $ad-bc=0$, in which case the general solution for $B$ depends on one parameter.   (this is question 22 of the last matrix exercise of Further Pure Mathematics by Bostock et al.)  Comments Writing $B=\bigl(\begin{smallmatrix} e&f\\ g&h \end{smallmatrix} \bigr)$ and multiplying out I get that    $(a+d)(f+g)+(b+c)(e+h)=0$ $ae+bg+cf+dh=0$   but I am unable to get the required restrictions on $a,b,c,d$. Is there a quick way of doing the problem that doesn't require manual computation? I thought of considering invertible and non-invertible cases but couldn't get anywhere. Help would be much appreciated.


I'm programming my ATmega16A through LPT port using uisp -dprog=bsd. Although ATmega16A supports \$V_{CC}=2.7\,\mathrm V\,..\,5.5\,\mathrm V\$, to make logical levels compatible with LPT port, I have to supply 5V to the ATmega.  All works fine, but now I need to connect MAX44009 lux meter (working via I²C) to the controller. MAX44009 supports \$V_{CC}=1.7\,\mathrm V\,..\,3.6\,\mathrm V\$, which appears too low to safely input 5V to it.  For transmitting data I could use e.g. a voltage divider to supply a fraction of 5V to MAX44009, and pull-up the SDA and SCL lines to this power source. Since SDA & SCL are open drain, this would work fine as far as we're only driving MAX44009's input. But when we want to read data back, we have a problem: 3.6V doesn't seem to be good enough to be seen as high level input for 5V-powered ATmega.  So, how can I actually safely connect ATmega16A to MAX44009, without losing the ability to program ATmega via LPT port? Some web pages like  simply suggest powering MAX44009 with 5V without explaining why. Others like  say that working voltage is 3 ~ 5 V, which also looks strange.

I'd like to interface an  sensor with an  using I2C. The Atmega operates at 5V while the sensor chip operates at 3.3V.  How can I find out if the two can work together? I'm not very used to reading data sheets and don't know what to look for.


With the current android app the bodies of questions/answers show all black, with links (URLs) in blue and equations in grey.  Just updated, no idea what version it is now.

Update: This is fixed on version 1.0.43 as per the accepted answer below.  Already saw ,  and . They are old and seem to be about previous versions.  I just updated to the version 1.0.41 of the Android app that brings the new feature - Achievements. Sadly, I think the stress of World Cup has made you guys not do a good job with it. It's buggy.  When I open my Achievements panel and tap on any post, I get this:    After I get this, it persists throughout the rest of the app. For example, if I go to the feed and open another question, I get this too.  Detailed reproduction steps are available in AD7six's answer.  My Device: Samsung Galaxy SIII LTE GT-I9305 Android: Stock ROM 4.3 Jelly Bean  Other Devices: - Device model, Android version, Reported by - HTC Desire, 4.2.2, xd6_ - Huawei Ascend, 4.2, Manu343726 - LG Optimus F3, 4.1.2, Rocket Hazmat - LG Optimus G, 4.3, Canadian Luke - Samsung Galaxy Nexus (Sprint), 4.3, Chrono Kitsune - Samsung Galaxy Note II, 4.3, Katja Christiansen - Samsung Galaxy SII GT-I9100, 4.1.2, AD7six - Sharp SH837W, 4.1.2, timrau - Sony Xperia SP, 4.3, pepoluan - Sony Xperia Z1, 4.3, user2313067 - Unknown, 4.2.1, Deer Hunter


I have installed two operating systems i.e. WINDOWS 10 and UBUNTU 16.04.  Windows 10 C: drive (shows /dev/sda5 in GParted) is 130GB whereas accidentally, Ubuntu 16.04 drive (shows /dev/sda2 in GParted under extended which is mounted) is 9.59GB and giving me no free space available which is a headache for me.  I have freed 90.66GB from Windows 10 drive (it had became 130GB) and I make it unallocated. Now, I wanted to MERGE it with Ubuntu drive but Ubuntu drive is mounted and the unallocated space tends to merge in C: drive instead of the Ubuntu drive.    Note: I have tried every possible solution but all in vain. I have tried using GParted in Ubuntu and Disk Management and Easeus Partition Master in Windows 10. In GParted, I can create standalone drive and also can merge in the C: drive but cannot merge in Ubuntu drive. Same happens for the Windows 10 softwares.

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


In the course of a monitoring exercise for small scale farmers, we captured the coordinates of fields using a GPS tracking in the SurveyCTO app. We used automatic capturing of the coordinates every 5 seconds to compensate for low GPS accuracy. Therefore, the coordinate list for every field is very long. With these coordinates, we would like to create polygons in QGIS to e.g. determine the size of fields. Unfortunately, the coordinates can only be extracted in one cell of an excel file. This looks like this:   Now my question is: Does anyone have a suggestion how we can import such a list into QGIS in a way that a polygon is created for each of these coordinate lists?

I am using QGIS 3.2 and I need to create an area to form a polygon shapefile using latitude and longitude, not using Python as I am just a beginner. How to do this?


trying to find a woodland mansion in creative, but I need help with the Y. When I run /locate, it says at block -9368 (y)? -28920 How do I know where to go if it won't tell me the Y value? Could someone please help with these coordinates -9368 (y?) -28920

I'm trying to find a woodland mansion in creative, but I need help with the Y. When I run /locate, it says at block 1576 (y)? -11176 How do I know where to go if it won't tell me the Y value?


Hi I am trying to induce a validation in custom object using trigger. The condition if InvoiceTotal">25000 then either second level approver field OR third level apporver field must have specht or Waterweg. If not it should throw an error before saving. Here is my code   trigger CT_PISA_ApproverValidations on CTPISA__BookingCapture__c (before update)  {     for(CTPISA__BookingCapture__c bc:trigger.old)     {                          if(bc.CTPISA__InvoiceTotalVATIncluded__c >= 25000)             {                 Boolean approver_check_ok=False;                 if(bc.Second_Level_Approver__r.LastName=='Specht'|| bc.Second_Level_Approver__r.LastName=='Waterweg')                 {                     approver_check_ok = True;                 }                 else if(bc.Third_Level_Approver__r.LastName=='Specht'|| bc.Third_Level_Approver__r.LastName=='Waterweg')                    {                     approver_check_ok = True;                 }                 system.debug('Flag ' +approver_check_ok);                 if(!approver_check_ok)                 {                     CTPISA__BookingCapture__c er= Trigger.newMap.get(bc.Id);                     er.adderror('For Invoices bigger than € 25.000 either Waterweg or Peter Specht have to be on the list of selected approvers.');                 }                     }                   }       }              Any idea why it is throwing error in all the scenarios even if one of the field satisfies the condition? I tried using validaiton as well but it fails to satisfy one of the conditions. IF( OR(NOT(OR( AND( CTPISA__InvoiceTotalVATIncluded__c >= 25000, NOT(CONTAINS( Second_Level_Approver__r.LastName , "Specht")) , NOT(CONTAINS( Second_Level_Approver__r.LastName , "Waterweg"))), AND( CTPISA__InvoiceTotalVATIncluded__c >= 25000, NOT(CONTAINS( Third_Level_Approver__r.LastName , "Specht")) , NOT(CONTAINS( Third_Level_Approver__r.LastName , "Waterweg"))))),AND(CTPISA__InvoiceTotalVATIncluded__c >= 25000,OR(NOT(CONTAINS( Second_Level_Approver__r.LastName , "Specht")),NOT(CONTAINS( Second_Level_Approver__r.LastName , "Waterweg"))), OR(NOT(CONTAINS( Third_Level_Approver__r.LastName , "Specht")),NOT(CONTAINS( Third_Level_Approver__r.LastName , "Waterweg"))))), true, false)

This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, navigate to the  tag. This question and answer is owned by the community! If you can improve it and make it more useful, you're welcome to edit it. I am building a trigger, a unit test, or other Apex code. I'm working with sObject records, and trying to access related record information. For example, I might have a structure like this: Account a = new Account(Name = 'Test'); insert a;  Opportunity o = new Opportunity(Name = 'Donation', AccountId = a.Id); insert o;  System.assertEquals(o.Account.Name, 'Test', 'Correct Account associated'); // Assertion fails!  Or, in a trigger, I might be aiming for something like this: trigger ContactTrigger on Contact (after insert) {     for (Contact c : Trigger.new) {         if (c.Account.Name == 'Test') {             // Take some action here         }      } }  Why doesn't this work? Why am I getting null values, or NullPointerExceptions?


I'm proving that $\overline{\mathbb{F}}_p = \bigcup\limits_{i=1}^{\infty} \mathbb{F}_{p^i}$ is an algebraic closure of $\mathbb{F}_p$ where $p$ is a prime. I think I've gotten down how to prove that $\overline{\mathbb{F}}_p$ is a field and that it is algebraic over $\mathbb{F}_p$. I have some difficulties with proving that $\overline{\mathbb{F}}_p$ is algebraically closed. My attempt is as following: Suppose $f$ is a non-constant polynomial in $\overline{\mathbb{F}}_p [X]$. If $\overline{\mathbb{F}}_p$ contains a root of $f$, then it is algebraiclly closed. Per definition there must exist a $\mathbb{F}_{p^k}$ for a certain positive integer $k$ that contains all the coefficients of $f$. Take a root $\alpha$ of $f$ and consider the extension $\mathbb{F}_{p^k}(\alpha)$. How is this now a field of the form $\mathbb{F}_{p^l}$ for a certain positive integer $l$?

What is the algebraic closure of $\mathbb F_q$ with $q$ being some power of a prime $p$ ?   I wrote, ''the algebraic closure'' because, they're the same up to isomorphism right ?  It cannot be finite, otherwise it is not algebraically closed, so how does it look like ?


Why is Naruto's Jinchuriki transformation so different from the true form of Kuarama??       In the first image, Kurama is in its true form and in the second one naruto is in biju transformed mode. Why is it so different? I mean all the lines and stuff drawn on it and it even looks different that the transformations undergone by other Jinchuriki's!! Is there an explanation for that?

In Naruto, Kurama (the Nine-tailed bijuu) appears as chakra, as does Killer B's bijuu, Gyuki.      Other bijuu, however, don't appear that way. What is different between them?


What would happen to light at absolute zero? Any change of a property? Or to say it in different words, what would happen to photons at absolute zero?    I have read that to slow down light, nearly to stop it,a cloud of nearly motionless atoms, at absolute zero, work. A physics professor in Harvard states so. But how is it possible, since light is not a matter but pure energy? I thought nothing would happen to light at absolute zero. I am confused.

I have a quick question about the refraction of light, and I'm sorry if it seems a bit simplistic or even stupid, but I'm still learning.  We know that when light passes through a denser medium, it slows down. However, is there a limit to that slowing down? If no, wouldn't it be possible, with some type of medium we make ourselves (like a crystal), to decrease the light's speed down to a point where we would be able to "see the photons moving forwards"?  I know it is way more complicated than that and that you can't see light unless some other light bounces off it, what I mean is slowing down light to an extreme and unusual speed). That sounds completely absurd but I can't seem to find what is wrong. Can anyone can explain it to me? :)


After (hopefully) scrubbing viruses out of a Windows 7 installation (after deciding not to simply run over the laptop repeatedly with my car), I've got everything almost back to normal. The only lingering issue I have is that for my non-admin users, the ".exe" file extension doesn't work. That is, clicking on the various desktop application links results in a "How do you want to open this?" dialog.  I've been through the alleged registry fixing from "winhelponline" and that had absolutely no effect.  I've tried running "assoc" for the affected users, but it reports the .exe association to be "exefile" even though it persistently does not work.  Right-clicking on a desktop icon and then choosing "start" does successfully open an application, but that's clearly a terrible situation.  For my admin user, things seem to work fine.  What do I need to do to get things working?

When I right-clicked into an .exe file then chose Open with... and I select choose a program then I selected the wrong program. I checked the checkBox that has the label Always use the selected program to open this kind of file.  Now all of the .exe files have changed into the wrong program after I did this, so all .exe file opened with this program.  How do I revert the .exe file associations to do my regular work?


I'm interested in Ubuntu Desktop certified hardware (Pre-installed by manufacturer) with NVIDIA GPUs. Is there a way to download a list of certified hardware including the GPU model (details like GPU-VRAM)? Thanks.

I am buying a new desktop PC in early 2013, anyway this question should apply to someone intending to buy a new laptop/ultrabook as well.  This machine is not meant for gaming, and if I ocasionally do it, I can survive with minimum graphics. However I may need some heavy multimedia edition or multitasking at times, so basically  my greatest priority is a good processor, after that perhaps average graphic card (if onboards are not enough, I am still not informed enough about that), at least 4GB of RAM with possibility of expansion.  I know there are some PC models specially designed to ship with Ubuntu, which is the OS I use the most these days. However, most people around me use Windows and some software with unsupported versions for Linux and not having a Windows license becomes a bit problematic.  Given that, I would like to find information about which PC models or even manufacters currently on the market have the best compatibility with Ubuntu, I am still undecided between building my own desktop or buying a pre-made model, so I would like to find information both for certified models and certified hardware or even Ubuntu partners that may work closely with Canonical.  Where to find this information in order to make sure that I will have a good experience with Ubuntu on my new PC in the years to come?


Given the research paper itself and having a complete understanding of the proposed system, I could implement the system on my own. If my intention is not to re-implement it myself, but rather study the original implementation(probably by the authors of the paper), I've got the following line of questions    Is it acceptable if I seek the original implementation of the paper?   Is it OK to contact the author(s), and request their implementation by giving a valid reason?   Are IEEE papers intellectual properties, that such a task of seeking implementation is entirely stupid?

I am in the field of computer science. It is often the case when I am reading a paper I start to wonder, "Wow stunning results, however, I would like to prove that." or "How exactly did he get these amazing results? He/she just wrote a rough overview of the real methodology used in this paper.". As you can see, a lot of times the small things have a huge impact on the overall performance of the underlying methodology. Often they are not part of the paper or not revealed at all.  My idea would be to contact the paper writer, to ask for his research programs to recreate them and understand them. Can/should I do that?   I personally think that there are probably not a lot of researchers, who would let somebody else "look at their cards". What's your experience with that?


This is not a continuously screw.   Thank you for your great help. Can someone tell me how to create this style of screw?

I'm trying to follow the following answer from the site:   I could do almost everything, but when I have to do the (spiral) loop cut the program doesn't allow me and I don't know why and in the answer there is no clarification of how it's done.     Additional info: Before I remove the screw (even after doing the knife intersect) I can do the spiral loop ring as the picture shows.  When I delete it I cannot do the spiral loop cut nor select the linked objects all the spiral with CTRL+L and I have to do it manually.


I have an application that does this : When the application starts,one row with 3 editTexts is created by calling a method called newproduct().The first of them is focused and this triggers the creation of another row of those 3 edittexts.So,when the last row is focused,another row is created dynamically. Every columns is inside a different linear layout and gets added to a new ArrayList<EditText>();,one for everyone of the 3 columns.The values that get entered are then put inside a String[],again,3 of them for every column.  My questions now are the following : 1.How can i save this on screen orientation changes? When i change the orientation,the values remain but only in two of the rows because those 2 rows are created at onCreate( newproduct method called,creates the first row, and then focused,so it creates another row).How can i tell my application to create more then 2 rows and keep the values ?  2.How can i make my application keep everything,the number of rows and their values and the whole UI layout when the user either exits the app or the app crashes.What i want here is when he enters the app again to see the state in which the app was left the last time.  Thanks in advance and have a nice day !

I've been working on the Android SDK platform, and it is a little unclear how to save an application's state. So given this minor re-tooling of the 'Hello, Android' example:  package com.android.hello;  import android.app.Activity; import android.os.Bundle; import android.widget.TextView;  public class HelloAndroid extends Activity {    private TextView mTextView = null;    /** Called when the activity is first created. */   @Override   public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);      mTextView = new TextView(this);      if (savedInstanceState == null) {        mTextView.setText("Welcome to HelloAndroid!");     } else {        mTextView.setText("Welcome back.");     }      setContentView(mTextView);   } }   I thought it would be enough for the simplest case, but it always responds with the first message, no matter how I navigate away from the app.  I'm sure the solution is as simple as overriding onPause or something like that, but I've been poking away in the documentation for 30 minutes or so and haven't found anything obvious.


I have a script, that configures some environment variables. Therefore it needs its own position, the value of $0.  I have another script that sources the first script, but it could also happen that the first script is sourced from the console.   However, neither $0, nor ${BASH_SOURCE[0]} seem to work consistently on MacOS. Here is a small example to show what I mean:   a.sh:  #!/bin/bash -eu source ./b.sh   b.sh:  #!/bin/bash -eu echo "$0" echo "${BASH_SOURCE[0]}"   Output of ./a.sh:  ./a.sh ./b.sh   Output of source ./b.sh:  ./b.sh <empty line, can't get stackoverflow to display it properly>   Not relevant, but just for completeness: output of ./b.sh:  ./b.sh ./b.sh   So, in short: If I use $0 to get the script name, it is wrong when sourced via another script. If I use ${BASH_SOURCE[0]}, it will be empty when sourced directly.   How can I get the script name in both cases?

How do I get the path of the directory in which a  script is located, inside that script? I want to use a Bash script as a launcher for another application. I want to change the working directory to the one where the Bash script is located, so I can operate on the files in that directory, like so: $ ./application


How can I extract volume and surface information from objects?   I create an objects (e.g. a monkey). With a Python command how do I extract an object's information like: volume, surface, location etc.?

The 3D print toolbox currently only outputs the volume/area of all faces.  How can I get the volume of selected mesh objects, ignoring certain faces?    Asking on behalf of a user who mailed me.


I am using Ubuntu 16.04 for the first time. Software center shows only the apps that were installed by default. When I tried to install vlc, playforubuntu or any other app, it show no app found.  I have also tried using terminal but not successful.       As requested in comments, images of software home page:

This is the error I get when I open the software center. I've tried rebooting and running sudo apt-get update but I see no improvement. It worked earlier but I don't know what went wrong since then. I'm using Ubuntu 16.04 final release on a Dell Inspiron 15R. Any advice will be appreciated. Thanks in advance.  EDIT: The problem magically solved itself without me doing anything special (or maybe inadvertently doing something, I don't know). So I'd still like to get to the root of this.


So, I've asked questions before that have been met with "Time (and our laws of physics) didn't exist before the big bang" and other answers to that effect. This is massively confusing to me, for reasons. While I understand that time could neither 1.) Be measured nor 2.) quantified, I want to intuitively assume that there was some non-zero amount of time during which the universe we live in now was an empty void. An absolutely perfect vacuum. It has no significant meaning, because in an empty and timeless void the probability of a big bang is apparently 1, but I can't help but see it as that.  So, I was wondering, if someone can clarify the statement and adherence to the phrase "Time didn't exist before the big bang". Whenever I ask about a question before it, I'm met with that statement (in a generally dismissive manner).

Did spacetime start with the Big Bang?  I mean, was there any presence of this spacetime we are experiencing now before big bang? And could there be a presence/existence of any other space-time before the big bang?


I have a list of packages from my repository say some_repo,   Few packages in that has two versions and when I run my script to fetch the packages from repository the two versions of package is being downloaded,  I just want the installed version of the packages,   How do i get it?  Eg:   Package, Version          xyz          1.2.3          xyz          1.2.3.4    For Package xyz Version 1.2.3.4 is been installed, I just want the installed version of those packages which has two or more version

Hello im just new for Linux   I know that  sudo apt-get   is for installing application   but how I would know that I have installed the latest version of the application   for example apt-get install sun-java6-jdk   is there an option to upgrade or see the latest version   or its ok to install an old version the application and Linux will upgrade it for me ?


If one of your questions has been closed, and you feel it should not have been, what it the best course of action?  Suck it up and live with it?  Vote to reopen and hope for the best?  Flag it and ask a mod to reopen it?  What is the community consensus on this?  Note: Do not assume the question has been closed because of poor quality.

As a newcomer to StackOverflow, I recently asked my first . I wanted to start with a fairly safe general question, to get the feel for how the site worked. My question was intended to be programming-related, but my original wording was not clear enough, so another user decided to close it.  I've re-phrased my question, and had received one useful answer before the question was closed, but I'm not sure what the procedure is after your question is closed to allow people to post answers again...  I've checked the FAQ and About pages, searched the SO questions, but have had no luck. Could someone point me in the right direction as to how I get my question re-opened, or if it is possible to do at all?


We say $U,V$ is a splitting of a Topological space $X$ if , $$ X = U \cup V    $$  where $U,V$ are Open, disjoint , non empty subsets of $X$  In a book I'm reading it says that for any Compact Haussdorf topological space and given two distinct connected components, a splitting can be chosen such that they lie on different sides of the split.  My question is, how do we show this? I realize compact haussdorf implies Normal but I'm not able to make an explicit splitting using that.

Let $B$ be a Stone space (compact, Hausdorff, and totally disconnected).  Then I am basically certain (because of Stone's representation theorem) that if $a, b \in B$ are two distinct points in $B$, then $B$ can be written as a disjoint union $U \cup V$ of open sets where $a \in U, b \in V$.    However, I can't seem to prove this directly.  The proof should be fairly straightforward, so I am sure I'm missing something obvious.  (As an exercise for myself, I'm trying to prove Stone's representation theorem, and I need this as a lemma.)


I am very new to working with Ubuntu and working with command line input. Last night I tried to install Netflix desktop app which required wine-compholio, wine-browser-installer and lib(I forget the rest of it). I noticed that when I was installing these, a lot of other programs were removed. After I installed the programs I tried to reboot my laptop. It wouldn't shutdown so I had to hard-shutdown. When turning it on again it gave me a "system is running in low-graphics mode" error. I have tried to solve the problem myself by researching it online but nothing has helped. I've tried using recovery mode, opening a terminal, trying to install nvidia and fglrx, but nothing has worked. Also, I keep getting the following warnings when trying to install anything in recovery mode terminal: caution WARNING: failed to detect canonical device of /dev/sda5 caution WARNING: could not determine root device from /etc/fstab  I really need some help.  Thank you, Edward

Note: This is an attempt to create a canonical question that covers all instances of "low-graphics mode" error that occurs to a user, including but not limited to installation of wrong drivers, incorrect or invalid lightdm greeters, low disk space, incorrect installation of graphics card like ATI and Nvidia, incorrect configuration of xorg.conf file while setting up multiple monitors among others. If you are experiencing the "low-graphics mode" error when trying to login but none of the following answers work for you, please do ask a new question and then update the answers of this canonical question as and when your new question gets answered.   When I try to boot into my computer, I am getting this error:  The system is running in low-graphics mode Your screen, graphics cards, and input device settings could not be detected correctly. You will need to configure these yourself.   How do I fix the failsafe X mode and login into my computer?  Answer index:


I just realized that the default permissions of every directory in /home is set to rwxr-xr-x, so that any unprivileged account can read the content of other people's files. Why is it so, and is it safe to change it ?

I just added a new, underprivileged "desktop user," and I was surprised to discover that it can see the files in my home folder.  What is the rational for setting up such lax permissions?


I installed Python3 yesterday, but I have the feeling I didn't do a good job:  :~$ gnome-terminal Traceback (most recent call last):   File "/usr/bin/gnome-terminal", line 9, in <module>     from gi.repository import GLib, Gio   File "/usr/lib/python3/dist-packages/gi/__init__.py", line 42, in <module>     from . import _gi ImportError: cannot import name '_gi' from 'gi' (/usr/lib/python3/dist-packages/gi/__init__.py)   I get the same error when trying to remove the PPA (in 404) with:   add-apt-repository --remove ppa:/jonathonf/python-3.7   And yet, Python runs smoothly.  This might be helpful too:  ~$ python --version Python 2.7.15rc1 ~$ python3 --version Python 3.7.0b3 ~$ type -a python3; file $(type -aP python3) python3 is /usr/bin/python3 /usr/bin/python3: symbolic link to /etc/alternatives/python3 ~$ python3.5 --version # Expected, I installed 3.6 and 3.7 - I only added the 3.5 link as a following desperate attempt bash: /usr/lib/command-not-found: /usr/bin/python3: bad interpreter: No such file or directory ~$ python3.6 --version Python 3.6.5 ~$ python3.7 --version Python 3.7.0b3   Running Ubuntu 18.04  The error persists after re-installing gnome-terminal.  I've found  that doesn't have an answer, but they suggest to re-install Ubuntu, like, I hope they're joking (:

I just tried to install python 3.6 on my Ubuntu 16.04 system, and now I can't run the terminal from the launcher or from Ctrl + Alt + T. I tried to run gnome-terminal from XTerm and got the following message:  Traceback (most recent call last):   File "/usr/bin/gnome-terminal", line 9, in <module>     from gi.repository import GLib, Gio   File "/usr/lib/python3/dist-packages/gi/__init__.py", line 42, in <module>     from . import _gi ImportError: cannot import name '_gi' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 23, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'  Original exception was: Traceback (most recent call last):   File "/usr/bin/gnome-terminal", line 9, in <module>     from gi.repository import GLib, Gio   File "/usr/lib/python3/dist-packages/gi/__init__.py", line 42, in <module>     from . import _gi ImportError: cannot import name '_gi'   How can I fix this error?  It should also be noted that:   My gnome-terminal file is now a python script. The gnome-terminal.real file will open the terminal as expected. python3.5 gnome-terminal will open the terminal as expected.


I'm reading through Spivak Ch.22 (Infinite Sequences) right now. He mentioned in the written portion that it's often not a trivial matter to determine the boundedness of sequences. With that in mind, he gave us a sequence to chew on before we learn more about boundedness. That sequence is:  $$1, 1+\frac{1}{2}, 1+\frac{1}{2}+\frac{1}{3}, 1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}, . . .$$  I know that a sequence is bounded above if there is a number $M$ such that $a_n\leq M$ for all $n$. Any hints here?

Can someone give a simple explanation as to why the       $$\sum_{n=1}^\infty\frac1n=\frac 1 1 + \frac 12 + \frac 13 + \cdots $$   doesn't converge, on the other hand it grows very slowly?   I'd prefer an easily comprehensible explanation rather than a rigorous proof regularly found in undergraduate textbooks.


I'll be traveling to Italy with my family next year for 15 days (We're Brazilians) and we will be staying on apartments rented with Airbnb. I heard immigration will ask for proof that I'm staying in a Hotel or an invitation letter.  Is the Airbnb booking valid as proof of stay?  [EDIT] My question differs from  because I'll be staying only 15 days.

We (Russian citizens) are planning to go to Munich in late June. We would like to book our accommodation on AirBnB, but it is not very clear whether it will be accepted by the German embassy when we apply for a Schengen visa.  I can't find such information on the German embassy site or on the VFS-Global site. I've also searched for it on the Internet, and, while most sites agree that AirBnB booking is generally OK for a visa, I don't see a clear answer for Germany specifically, and there seems to be some exceptions for other European countries.


I want my \section is always in a new page, so I need a \newpage before \section.  What about the current page is new page already? How do I avoid it?

I would like to start each section on a new page. Is adding the following to my preamble this the preferred method, or a hack?  \let\stdsection\section \renewcommand\section{\newpage\stdsection}


Is there a word meaning both import and export?  So I can ask "Is this product both importable and exportable?" like "Is this product ____?"

What word could describe an operation of either importing or exporting?  X is to import and export as migration is to immigration and emigration.  Porting isn't the word I'm looking for, I don't think, but that's what I'm getting at. Cheers!


I am going to mount a TV to a wall in my living wall. The only problem I have is the TV weighs about 50kg and I am little bit afraid of hanging this amount of weight on pure plasterboard.  Is it safe to do so?   TV i am trying to put on the wall:       The wall mount that I am planning to buy:      I am aware of where the studs are.

I have a TV wall panel that can only reach two studs. I was wondering if it's fine to screw the left side and the center on studs, and have the right side anchored in the drywall.  My TV is 30lbs with the mount.  Also, the TV would be mounted a bit on the right of the TV mount. Does it matter if the weight is not 100% centered?


In finance, technical analysis is a security analysis methodology for forecasting the direction of prices through the study of past market data, primarily price and volume.  Is there any evidence (public available) that technical analysis actually works?

Do you find  to be an effective way of increasing the returns on your investments?  This can be either by itself, or in combination with other indicators.  If so, what techniques do you use?    What studies exist which show evidence for whether or not different techniques work?


last day I installed Ubuntu 16.04 On a brand new hp 14 ap-000 series. I have wiped away the whole harddisk and I only have Ubuntu on it now. But I really need to go back to WIndows 10. But I don't have any recovery image or Iso file, how can I go back now? I asked my friend to crate an recovery image on his Windows 10 pc, so, how can I use this to go back?

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


I've run into a Javascript/JQuery issue I was hoping you'd know how to solve.  Suppose I define this function that builds a table inside of the 'div' with id 'TableHolder':  MakeTable = function() {     document.getElementById('TableHolder').innerHTML = "";     var tablebuild = "

";     for (i=0; i<3; i++)     {         tablebuild += "	";     }     tablebuild += "

";     document.getElementById('TableHolder').innerHTML = tablebuild; }   I call this function when the document is ready, and tell JQuery to rebuild the table when any cells are clicked.  $(document).ready(function() {     MakeTable();     $('td').click(function(){         MakeTable();     } });   Once a cell is clicked and MakeTable() rebuilds the table, the JQuery no longer works for the new cells.   Is there any way to fix this issue without using a loop?   *The above is a bread and butter version of a program that actually has a purpose, and I recognize it's useless as presented. Yet, the solution applies across the board.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


I don't know exactly if the terminal is the handler of keystrokes like CTRL + C or CTRL + D and many others or the shell.   When I press a keystoke I think about it this way, as the picture describes:     When a keystroke is pressed, the keystrokes is handled by the shell, the shell interprets the keystrokes and do whatever it needs to do, perhaps sending a signal when CTRL + C is pressed or clearing the screen with CTRL + L and so on. Therefore, the shell plays the role of the middle-man for the program's inputs. Inputs go from shell to the program's stdin.   The program's stdout goes to the shell, and the shell redirects the output to a terminal or files or pipes.   The terminal sends the shell the bytes of the pressed keys.   Am I right?

I think these terms almost refer to the same thing, when used loosely:   terminal shell tty console   What exactly does each of these terms refer to?


$E=mc^2$ Does not this imply that there is no energy without mass,  or is it strictly a conversion formula?

Einstein equation  where $E$ is energy, $m$ mass, and $c$ the speed of light in vacuum. So does it mean objects without any mass does not posses energy for eg lights photons does not have mass but how can they posses energy


In particular, $S_3$ is the group of permutations of $\{1,2,3\}$, and $D_6$ is the dihedral group of symmetries of the triangle (written as $D_{2\cdot 3}$). In generator-relation form, $D_6 = \left< r,s \mid r^3 = s^2 = e, rs = sr^{-1} \right>$.  I can intuitively see very easily that the two groups are isomorphic; the symmetries of a triangle can be viewed as orderings of the vertices (1,2,3).  However, proving this rigorously, I need some help.  Is the following proof correct?  Let $f : D_6 \to S_3$ be a homomorphism. Define $f(r) = (123)$ and $f(s) = (12)$. Then $$f(r)f(s) = (123)(12) = (13) = f(rs)$$  and we need this to equal $$f(sr^{-1}) = f(s)f(r)^{-1} = (12)(132) = (13)$$   which is indeed true. Since the order of $f(r)$ is $3$, and the order of $f(s)$ is $2$, and $f(r)$ / $f(s)$ cannot be produced using each other, the group $X = \left< f(r), f(s) \mid f(r)^3 = f(s)^2 = e, f(s)f(r)^{-1} \right>$ is isomorphic to $D_6$. But $X$ contains $6$ elements and so does $S_3$, so by closure in $S_3$, we must have $X = S_3$.     Are there any general tips for proving isomorphism? Is it a good idea to look at generators and relations between generators, and try to find a correspondence?  Thank you!

So I'm asked to prove that $$S_{3}\cong D_{3}$$ where $D_3$ is the dihedral group of order $6$. I know how to exhibit the isomorphism and verify every one of the $6^{2}$ pairs, but that seems so long and tedious, I'm not sure my fingers can withstand the brute force. Is there a better way?


Four spokes on backwheel of Riverside 500 ebike just snapped when I was going uphill. Anyone else had this problem or know why it could have happened?

When replacing the rear brake pads I noticed that 4 spokes were broken and the wheel wobbles.  I phoned a local bike shop and was told that they recommend replacing the wheel if more than 3 spokes are broken.  I assume that this is a safety precaution but wonder if the recommendation is in line with common practice.  I certainly have no desire to get thrown off the bike in traffic, but it also seems a waste to (probably) discard an entire wheel because it might be damaged and might fail at some point.  This is a 27" road bike, inexpensive, which I ride for transportation in the city (Tokyo).  The rear rim is a bit scored from waiting too long to replace the brake pad, which is another factor to consider.  To clarify slightly, it probably would be cheaper to replace the wheel as suggested below.  My objection is more of an ethical one -- tossing something useful into a hole in the ground seems irresponsible.  Difficult to avoid though, the way things work right now.


In Charles Pinter's A Book of Abstract Algebra, Chapter 2: Operations, Section B. Properties of Operations, Question 7 part ii, an operation * is defined on the set of real numbers: $x * y = \frac{xy}{x+y+1} $ I need to find if it is associative, so: $$ \begin{align*} x*(y*z) &= x* \frac{yz}{y+z+1} \\\\ &= \frac{\frac{xyz}{y+z+1}}{x+\frac{yz}{y+z+1}+1} \\\\ &= \frac{\frac{xyz}{y+z+1}}{\frac{xy+xz+x+yz+y+z+1}{y+z+1}} \\\\ &= \frac{xyz}{xy+xz+yz+x+y+z+1} \\\\ \end{align*} $$  Then the same answer for $(x*y)*z$. This is not the same as the answer given at the end:   What have I overlooked?

I'm just getting started with Pinter's A Book of Abstract Algebra, please be kind. The book solution for Chapter 2, Problem 7 claims that the following operator is non-associative:  $$ x * y = \frac{xy}{x+y+1}$$  The book solution:  $$ (x * y) * z = \left(\frac{xy}{x+y+1}\right) * z = \frac{xyz(x+y+1)}{x+y+z+xy+yz+xz+1}$$  $$ x * (y * z) = x * \left(\frac{yz}{y+z+1}\right) = \frac{xyz(y+z+1)}{x+y+z+xy+yz+xz+1}$$  However the $(x+y+1)$ and $(y+z+1)$ terms appear to actually cancel out:  $$ (x * y) * z = \left(\frac{xy}{x+y+1}\right) * z = \frac{\left(\frac{xy}{x+y+1}\right)z}{\frac{xy}{x+y+1} + z + 1} $$  $$ x * (y * z) = x * \left(\frac{yz}{y+z+1}\right)  =\frac{x\left(\frac{yz}{y+z+1}\right)}{x+\frac{yz}{y+z+1} + 1} $$  So the denominators cancel out, the two groupings are equivalent, the operator is associative.  This result is duplicated in Mathematica, but I'd like to make sure I'm not missing something.  Sorry for bothering people with such a basic question.


public with sharing class JournalPage1 {  public integer limitvalue=5; public integer offsetvalue=0; public integer papersize=0;     public Date endDate { get; set; }          Public Date startDate { get; set; }      public List<Author_Research_Paper__c> AuthList { get; set; }      public boolean Showdetailsflag { get; set; }      public List<wrapJournalPage1> WrapList { get; set; }     public PageReference lastPage() {     offsetValue = papersize - limitValue;     callQuery();              return null;     }    public PageReference nextPage() {   offsetValue = offsetValue + LimitValue;     callQuery();         return null;     } public PageReference previousPage() {    if(offsetValue > 0){     offsetValue = offsetValue - LimitValue;     callQuery();     }         return null;     }    public PageReference firstPage() {     offsetValue = 0;     callQuery();         return null;     }  public void callQuery(){  WrapList = new List<wrapJournalPage1>(); // list<Research_Paper__c> rlist=[Select id from Research_Paper__c];   papersize=count;   for(Research_Paper__c rc:[Select Id,Name, Paper_Title__c,Name_of_Primary_Author__c,Status__c,Publication_Date__c from Research_Paper__c  limit:limitvalue OFFSET:offsetvalue]){                wrapJournalPage1 obj=new wrapJournalPage1(rc);                             Wraplist.add(obj);                              }                            }  public void Showdetails() {          List<Id> rpID = new List<Id>();          for(wrapJournalPage1 wp : wrapList)          {          if(wp.flagWrap==true)          {          rpID.add(wp.rcWrap.Id);          }          }          for(Id i : rpID)          {      AuthList=[Select Id, Research_Paper__r.Name, Research_Paper__r.Paper_Title__c, Author__r.Name,                       Research_Paper__r.Status__c, Research_Paper__r.Submission_Date__c                        From Author_Research_Paper__c                        Where Research_Paper__c =: i];          }                    Showdetailsflag=true;     }       public void updated() {         Research=[Select id from Research_Paper__c];                                      count=Research.size();     }     public Integer count { get; set; }      public List<Research_Paper__c> Research { get; set; }          public JournalPage1() { Research=new list<Research_Paper__c>();  }    public PageReference Show() {           WrapList = new List<wrapJournalPage1>();          if(startDate!=null && endDate!=null)     {          Research=[Select Id,Name, Paper_Title__c,Name_of_Primary_Author__c,Status__c,Publication_Date__c from Research_Paper__c where Publication_Date__c>=:startDate AND                                          Publication_Date__c<=:endDate limit:limitvalue OFFSET:offsetvalue];                             count=Research.size();                             for(Research_Paper__c rc:Research)                             {                             wrapJournalPage1 obj=new wrapJournalPage1(rc);                             Wraplist.add(obj);                             }     }             return null;     }     Public class wrapJournalPage1{          Public Research_Paper__c rcWrap{get; set;}     public boolean flagWrap{get;set;}          public wrapJournalPage1(Research_Paper__c rc){             this.rcWrap=rc;             this.flagWrap=false;     }          } }

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Specification of my laptop are : CPU Intel Atom N450(1.66 GHz, 512 KB cache, 1 GB Memory. Which will be a suitable Ubuntu and how to install it?

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I am validating my form using javascript validation as whole validation is working fine but email validation is not working. My form code is as follows  <form method="post" action="contact.php" name="myForm" onsubmit="return validateForm()">
To know more contact us today.

             Name:
                 <input id="name" name="name" type="text" />

             Contact No:
                 <input id="contact" name="contact" type="text" />

             Email:
                 <input id="email" type="text" name="email" />

             Address:
                 <textarea cols="34" id="address" name="address" type="text"></textarea>

                              <input type="submit" value="Submit" />

 </form>   and my javascript code is as follows

Is there a regular expression to validate an email address in JavaScript?


After going through this  I'm quite scared!  It's not that I don't want to use sudo rm command, but I want to inhibit the execution of the sudo rm -rf --no-preserve-root / command. If this command can ruin a motherboard, Why does it even exist ? or Why should it even exist ?

Is it possible to remove a terminal command? For example, if there was a command call lookup (not an alias), how would I go about removing it?