Is this a possible monopole setup, or will it cancel out?

Suppose you have a ball that is covered in magnets, in which the North Pole of every magnet faces outward. Is this a monopole? Or at least "functions" as a monopole? And what will happen if you placed the ball over a floor tiled in magnets with the North Pole of every one facing up?  Also, I recently saw another poster's question on what would happen if you positioned a ball plated in magnets North Pole outward inside a hollow ball that was plated on the inside North Pole facing inward. One answer-er said if you built the sphere perfectly, then the forces would cancel out, and the ball would drop to the floor. The answer for me seems kinda counter intuitive, as if the ball was dropping toward the floor, the bottom-hemisphere's magnetic field would have greater potency while the upper hemisphere's would fade away. Wouldn't it just levitate at least? Of course not in the center, as it is affected by gravity, but wouldn't it still levitate contrary to one of the physical laws I heard of? Thanks guys, I'm kinda confused.


What are the hotkeys to navigate the timeline?

I am looking for a way to move the timeline a specific amount, scroll, etc. even if the Timeline window is not open. Is this possible?


I am working on an Android application that will need several entries (a single table, with 1000-10000 rows) populated in that app's database before the user can use that app.  I've looked around some tutorials and I am unsure of the best way to do this.  Should I just check if the database exists each time the app is started and, if it isn't there, create it and insert the thousands of records I need?  Or is there a better way to handle this problem?  Ideally, it could be included as part of the app's install process, but I'm not sure if this is possible.  Any feedback would be greatly appreciated.


Connect 8086 cpu to memory chips and io devices in proteus

I have a project based on simulating operation of 8086 processor with memory and I/O devices using Proteus simulator.   Memory is eight 2K 6116 chips and I/O contains 2 seven-segment displays and a 4x3 keypad beside the address flip flops, logic gates for even and odd addresses and transceivers.   Also, I am interfacing memory using 74138 decoder and interfacing I/O with 8255.   The problem is that, during simulation, no value comes on address/data bus of processor, Meaning that control ports of 8086 have the values required as told in assembly code but every 20 bit address (16 bit address/data and 4 bit address A16..A19) take high Z value.   Is there anything wrong with internal memory start address (which is set to 0x00000) or assembly code?  .MODEL SMALL .STACK 64 .DATA     PORT_A EQU 60H;     PORT_B EQU 62H;     PORT_C EQU 64H;     PORT_CON EQU 66H;   .CODE  MAIN    PROC         MOV AX, @DATA;         MOV DS, AX;          ;Write arbitary values to memory         ;RAM1         MOV AL, 8H;         MOV BX, 14000H;         MOV [BX], AL;          ;RAM2         MOV AL, 7H;         MOV BX, 14800H;         MOV [BX], AL;          ;RAM3         MOV AL, 6H;         MOV BX, 15000H;         MOV [BX], AL;          ;RAM4         MOV AL, 5H;         MOV BX, 15800H;         MOV [BX], AL;          ;RAM5         MOV AL, 4H;         MOV BX, 16000H;         MOV [BX], AL;          ;RAM6         MOV AL, 3H;         MOV BX, 16800H;         MOV [BX], AL;          ;RAM7         MOV AL, 2H;         MOV BX, 17000H;         MOV [BX], AL;          ;RAM8         MOV AL, 1H;         MOV BX, 17800H;         MOV [BX], AL;           ;Load control word         MOV AL, 92H; (selection)(mode 0)(port A input)(port B input)(port C output);         OUT PORT_CON, AL;  PROG:            ;Interpret keypad         IN AL, [PORT_A]; COL:    CMP AL, 2H;         JNZ C1;         MOV BX, 2H;         JMP ROW; C1:     JG C2;         MOV BX, 3H;         JMP ROW; C2:     MOV BX, 1H;  ROW:    IN AL, [PORT_B];         CMP AL, 2H;         JNZ R1;         MOV CX, 1H;         JMP CALC; R1:     JG R2;         MOV CX, 2H;         JMP CALC; R2:     MOV CX, 0H;  CALC:   CMP CX, 0H;         JZ ENDKEY;         ADD BX, 3H;         SUB CX, 1H;         JMP CALC;          ;Calculate multiply ENDKEY: MOV DX, [BX];         MOV AL, BL;         MUL DL;          ;Display output         OUT PORT_C, AL;         JMP PROG;          MOV AH, 4CH;         INT 21H; MAIN    ENDP         END MAIN ```


what happens if we install two boot images in a pendrive?

I have a Ubuntu 12.04 image in my 16 GB Moserbaer pendrive. i am willing to install another image in it with out losing this 12.04.  i'm using Universal USB installer 1.9.4.3.  Thank you.


Even though I’m familiar with quantum mechanics, I’m unfamiliar with general relativity, so I hope for an explanation simple enough that I can understand. As far as I know the following three (contradictory?) statements are correct, how do they coexist?  Light is described as a reservoir of photons, which are massless.  Gravitational forces are proportional to mass, which would mean massless particles should not participate in gravitational interactions.  Light bends due to gravitational pull.   My questions are:  If photons are massless why do they interact with mass? My understanding is that it has to do with curvature of spacetime. Does it mean that slower massless particles, which should be less susceptible to relativity, don’t interact with mass?


Poker in the Star Trek universe: What are the stakes?

Obviously, when gambling with Ferengi or other aliens, the stakes are usually latinum. But on the Enterprise (or in Federation space in general), are they still playing for latinum, or are they betting chores (as seen in Firefly) or maybe holodeck time or replicator credits? I did a quick check on , but it's not really spelled out what the poker players on the Enterprise-D are betting. I'm fairly sure they're not just playing for fun.  I'm asking about Star Trek in general, not just the poker games we see on TNG.


How to get indicators back in top panel on GNOME 3?

I have recently installed Ubuntu Gnome with Gnome 3 running on it. I have installed various programs on it which in Unity would have a little icon which would go on the right on the Unity panel, such as Skype, Steam, and Shutter. However in Gnome when launching these applications I see no such icons appearing anywhere.    So do they appear somewhere? Can I make them appear somewhere (such as where they would appear in Unity) if not?


In the some sentences there are several verbs that goes by one another, e.g.:     You both have to go get dressed before ... (something happens)   Subject phrase: "you both"  Verb phrase: "have to go get dressed"  Main verb: "have to go"   What the grammar function of the remaining part of the verb phrase "get dressed"? Should the particle "to" precede the verb "get" in order to form "to get dressed" phrase?


speed of the light emitted from a fast moving object

Would not speed of the light emitted from the front of the fast moving object be the speed of light + the speed of the fast moving object?


Let $A$ be a ring and $\mathfrak{b}$ be an ideal of $A$. Prove that the assignment   $$\mathfrak{c} \mapsto \mathfrak{c}/\mathfrak{b}$$   induces a one-to-one correspondence between the ideals of $A$ that contain $\mathfrak{b}$ and the ideals of $A/\mathfrak{b}$.   This is a problem I've been given, typed exactly as I received it. I find it a bit unclear, but I think $\mathfrak{c}$ is meant to be an ideal of $A$ which contains $\mathfrak{b}$. Then I must prove that the map given is bijective.  I've seen quotient rings, but not between ideals before. Should I treat it as I would any other quotient ring?  Assuming what I've said is correct, if the map above is $f$, then I must show that $f(\mathfrak{c})=\mathfrak{c}/\mathfrak{b}=\lbrace x+y : x \in \mathfrak{c}, y \in \mathfrak{b} \rbrace$ is a bijection?


Problem with packages subfiles and import.sty after using TexLive Utility for updating

Everything worked fine before using TexLive for updating my packages three days ago. Now it is not possible anymore to use the package subfiles   Here are the MWE  The minimum Preamble.tex file  \documentclass{amsart} \usepackage{subfiles}   The MWE.tex file  \documentclass[MWE.tex]{subfiles} \begin{document} MWE \end{document}   When I compile the MWE file I get on the console  This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019) (preloaded >format=pdflatex)  restricted \write18 enabled. entering extended mode  (./MWE.tex  LaTeX2e <2020-02-02> patch level 5  L3 programming layer <2020-02-25> (/usr/local/texlive/2019/texmf-dist/tex/latex/subfiles/subfiles.cls  Document Class: subfiles 2020/02/14 v16 Multi-file projects (class)  Preamble taken from file `MWE.tex'  (/usr/local/texlive/2019/texmf-dist/tex/latex/tools/verbatim.sty)  (/usr/local/texlive/2019/texmf-dist/tex/latex/import/import.sty)  ! LaTeX Error: File `import.sty' not found.  Type X to quit or <RETURN> to proceed, or enter new name. (Default extension: sty)  Enter file name:   I checked and the import.sty file is in the right directory, and everything worked fine before. Do you have any idea about what happened (apart from the fact that I should not upgrade stuff before the official releases of TexLive I suppose  ...)?


Can I install Ubuntu to my 32 GB USB pen drive?

I want to install Ubuntu like how you would to a hard drive so I can use it as a portable system. I do not want a Live install; I want something where i can install updates, install drivers, and things like that. I'm really confused because I made a persistent install using UNetBootIn in Windows thinking that would allow me to do that and yet when I booted I still saw the "Install Ubuntu 12.04 LTS" icon.


CHAOS-like option for moderators to edit without bumping

CHAOS members have (had?) :     Because they are doing so many edits at once, CHAOS operates in a special mode where editing a title does not bump it to the home page.    I moderate at Writers.SE, and I can attest that this ability would be extremely beneficial to mods as well, and for the same reasons. On beta sites, wide-ranging changes are not infrequent. An established tag might be ruled problematic; a certain class of questions might need cleanup; etc. etc.. When this happens, the ensuing edits flood the front page with old content (frequently the somewhat problematic content the new change has come to address...). Furthermore, since beta sites are much less active than established ones, this flood can drown out recent activity, and then wallow around on the front page for some time.  I propose, then, the implementation of a moderator tool for editing without bumping. The value to beta sites is clear; the danger of abuse, as a mod tool, is nonexistent.


If two one sided limits exist, the two sided limit exists.

prove that if the limit as x approaches a from the positive side of the x axis, f(x) = L, and if the limit as x approaches a from the negative side of the x axis, f(x) = L, then the limit as x approaches a of f(x) = L as well.


Add a new partition to Ubuntu and append it to /var/www/

I have installed an Ubuntu server on a VMWare workstation with a space of 20GB storage as seen below;    After the installation I've attached another 40GB worth storage to the existing Ubuntu server installation (seen below);    Now I want to add this 40GB to my / (root) directory or to /var/ directory but my df -h result shows;  root@Userver:~# df -h Filesystem      Size  Used Avail Use% Mounted on /dev/sda1        18G  900M   16G   6% / udev            990M  4.0K  990M   1% /dev tmpfs           400M  308K  399M   1% /run none            5.0M     0  5.0M   0% /run/lock none            999M     0  999M   0% /run/shm none            100M     0  100M   0% /run/user root@Userver:~#   What should I do now? Further, I have only ssh access to the server.


Why was the plan for the Purple Wedding so complicated?

Spoilers for A Storm of Swords / Season 4 episode 2 "The Lion and the Rose".  At the Purple Wedding,      Littlefinger and Lady Olenna Tyrell   perform their plan of      poisoning King Joffrey.   A short summary of their plan:  Littlefinger orders Ser Dontos Hollard to give Sansa Stark a beautiful silver hairnet adorned with amethysts. At least some of the amethysts are actually strangler crystals in disguise. Ser Dontos also, still under orders of Littlefinger, urges Sansa to wear the hairnet at the wedding, which she then does. At the wedding, when Lady Olenna greets Sansa, she fusses her hairnet a bit, while secretly taking one of the strangler crystals. Later, during the wedding, Lady Olenna puts the crystal in Joffrey's royal cup, poisoning him.  But why was their plan so complicated? Why couldn't Lady Olenna just bring a strangler crystal with her to the wedding (as suggested in )?  Then they wouldn't depend on Ser Dontos and Sansa who could unknowingly have done something to prevent the success of the plan.  The only reason that I could think of, is Littlefinger and Lady Olenna plan for Sansa (and Tyrion as her husband with her) to take the blame for Joffrey's death.  They put the crystals on her person, so that upon examination it would clearly show that Sansa had the murder weapon on her. But Littlefinger had a plan he did not tell Lady Olenna, namely rescuing Sansa during the chaos ensuing the murder (and thereby leaving Tyrion behind as the only accused).  Is there anything confirming or debunking this theory? If my theory doesn't hold up, is there another explanation for why the plan was so needlessly complicated?


Kripke models - prove that formula is not tautology in intuitionistical logic

My teacher proved that following formula is not tautology in intuitionistical logic: $$\neg(p\wedge q)\Leftrightarrow (\neg p\vee\neg q)$$ Is it sufficient to show (and we try to do it) that $$\neg(p\wedge q)\Rightarrow (\neg p\vee\neg q)$$   is not tautology. My teacher wrote red and black formulas. My formulas are green  - there are formulas that to my eye my teacher forgot to write. I know that teacher give arbitrar Kripke model. Tell me please: 1. If my green "supplement" is correct ? 2. From what my teacher conclude red formulas ?  When it comes to black things I know that it is about kripke model.


How can I find the following limit :$$\lim_{n\to\infty}\left(1-\frac{1}{3}\right)^2\left(1-\frac{1}{6}\right)^2\left(1-\frac{1}{10}\right)^2\cdots\left(1-\frac{1}{\frac{n(n+1)}{2}}\right)^2$$There are four options $(a)\frac1{3}(b)\frac1{9}(c)\frac1{81}(d)0$ Thanks!


If $R/P$ is an integral domain then $P\vartriangleleft R$ is prime.

Let $R$ be a ring and let $P$ be a proper ideal of $R$.  If the quotient ring, $R/P$ is an integral domain then $P\vartriangleleft R$ is prime.  For $x,y\in R$ we have $(x+P)(y+P)=xy+P\in P\vartriangleleft R$, and since $P\vartriangleleft R$ is an integral domain $x,y\neq 0$.  Also, we have that $R$ and $P\vartriangleleft R$ are rings, so there exists a zero element such that $$(x+P)(y+P)=xy+P=0_R+P=(0_R+P)(0_R+P).$$  Since $x,y$ are nonzero this is possible only if $x\in P$ or $y\in P$.  Therefore $P\vartriangleleft R$ is prime by definition.  Is my proof correct? I would appreciate any help/hint.


Why the moon doesn't fall down to earth?

Why the moon doesn’t fall down to the earth? We know that the moon travels in speed perpendicular to the gravity of the earth so that it doesn’t fall down to earth. But what if we supposed that the moon is stationary and the earth is stationary also but rotating around its axis? I drawn the attached two charts to explain my question:


How do I detect whenever a player looks at an entity?

So, I'm trying to make a gravity gun type thing in Minecraft. What I have so far is as follows. A command block which is always powered and has the command: /enchant @p sharpness 2  (it detects when you hold a sword). And a command block which would be the output that has execute @p ~ ~ ~ tp @e[type=villager] ^ ^ ^5 facing ^ ^ ^  Any help? I just need a command that detects if you look at a villager.


When are you supposed to use escape instead of encodeURI / encodeURIComponent?

When encoding a query string to be sent to a web server - when do you use escape() and when do you use encodeURI() or encodeURIComponent():  Use escape:  escape("% +&=");   OR  use encodeURI() / encodeURIComponent()  encodeURI("http://www.google.com?var1=value1&var2=value2");  encodeURIComponent("var1=value1&var2=value2");


Error under Ubuntu with the method String.join

I use the lib commons-lang-2.4.jar for my project. I develop under Windows, then send everything (including those libs) to Ubuntu server 4.6.3 Under windows, everything works fine. But when I launch my program under Ubuntu, I get this error:   java.lang.NoSuchMethodError: java.lang.String.join(Ljava/lang/CharSequence;[Ljava/lang/CharSequence;)Ljava/lang/String;   How can I fix it?


How to store one bit without the use of an IC?

I am trying to store a bit of data from a circuit, but I don't want to use an IC like an EEPROM chip. Is it possible to store one bit with a transistor or something else to that effect?


How does concentration work when wild shape is ended through damage?

Consider the following situation (round numbers chosen for easier calculations):   Bob is a human druid. In caster form Bob has a +0 CON modifier and 100 current HP. Bob is concentrating on a spell. Bob is wild-shaped. His current beast form has a +5 CON modifier and a current HP of 30.   What concentration checks are required (including DC and modifier used on the roll) if:   Bob is dealt 30 damage Bob is dealt 60 damage   As far as I know concentration is not automatically broken in either situation because although  he is never unconscious.


Dungeons and Dragons novel where girl accidentally wishes to be strong

Does any one know the name of the novel, written before 1995, from one of the Dungeons and Dragons series, where a girl accidentally wishes to become strong at the start of the novel? I remember that the protagonist is surprised and dismayed to have become strong. I can't remember which realm this was in.


Entry point for Java applications: main(), init(), or run()?

So far I've been using public void run() {} methods to execute my code in Java. When/why might one want to use main() or init() instead of run()?


To have this kind of arrow thing between enumerate's items

I want this    How can you make such an arrow for enumerate's items?


Why are removable discontinuities even discontinuities at all?

If I have, for example, the function $$f(x)=\frac{x^2+x-6}{x-2}$$ there will be a removable discontinuity at $x=2$, yes?  Why does this discontinuity exist at all if the function can be simplified to $f(x)=x+3$?  I suppose the answer is that you can't simplify it because you can't divide by something that could potentially equal $0$.  But what if you start with $f(x)=x+3$? What's stopping you from multiplying it by $1$ in the form $\frac{x-2}{x-2}$? Can multiplying by $1$ really introduce a discontinuity to the function?


Reopening feature requests with status declined

Sometimes I find interesting  which has . However, I think that such feature should be implemented and it's possible that other community members also think that. How to handle that case?  I could upvote such question, but then, it wouldn't be clear which upvotes were made before declining the feature, and which after.   I could create new question with similar feature request, but it would be probably closed as duplicate.  I could post a comment that I don't agree with that decline and hope the folks thinking the same would upvote it.  What is the etiquete for showing disagreement with ?


How do I get the Ubuntu Dock off the secondary monitor?

I updated to Ubuntu 18.04 a few weeks ago with little to no problems until now. After an update I installed and a reboot, my sidebar (Ubuntu dock) shows on the secondary screen, which is my Laptop, while my HDMI monitor is saved as the primary and has the top bar with time, battery and so on.   How can I get the sidebar back to my primary screen?


This question originates from Pinter's Abstract Algebra, Chapter 22 Exercise E1.     Let $a$ and $b$ be integers. Suppose $a$ is odd and $b$ is even. Prove that    $\operatorname{gcd}(a,b) = \operatorname{gcd}(a+b, a-b)$.   Attempt:  Let $d=\operatorname{gcd}(a,b)$ and $d' = \operatorname{gcd}(a+b,a-b)$.   Given $a$ is odd and $b$ is even, $d, a+b, a-b$ and $d'$ must all be odd, for the sum or difference of an odd and even number is an odd number, and the common factor of an odd and even number is an odd number. By Theorem 3 in Chapter 22, $d=\operatorname{gcd}(a,b)$ iff $ax+by=d$ for some integers $x$ and $y$. This implies $ax$ is odd, which implies $x$ is odd, for otherwise $d$ would be even contradicting (1). $d' = \operatorname{gcd}(a+b,a-b)$ iff \begin{align*}     (a+b)x' + (a-b)y' &= d' & \text{for some }x',y'\in\mathbb{Z} \\     a(x'+y') + b(x'-y') &= d' \\     \implies &d = d' \end{align*} for there exists a unique non-negative generator in the principal ideal of all the linear  combinations of $a$ and $b$ (by the proof of Theorem 3 in Chapter 22). In particular, observe that \begin{align*}     x &= x' + y' \\     y &= x' - y' \\     x - y &= 2y' \end{align*} $x$ is odd by (2) so $y$ must be odd, for otherwise $x-y$ would not be divisible by 2.   Does this look reasonable?


Sometimes I encounter ain't, but I really don't know how to translate it properly.    What does ain't stand for? If I really wanted to use it, in which contexts would you say it's acceptable using it?


Having been thinking about some of my favorite Sci-Fi shows from long ago I managed to jog my memory about one I just barely remember.  Hopefully, with the bit of detail I do remember someone might be able to recognize it.  First, the production details:   It would have been aired ~15-20 years ago in Canada (likely on the then equivalent of the Space Channel, but I don't guarantee that) It was in English It was definitely not animated, no puppet people either It was definitely a series, but I cannot remember the number of seasons it might have run for It could have been a rebroadcast of a show earlier, but it was definitely new to myself and the station at the time. It was definitely aimed towards a younger audience (Young me at the time would not have been watching an adult TV series)   Now, for what I do remember.  Take everything with a grain of salt, as particulars might also be mixed up with other shows (I'll make note of parts I'm not sure of:   There were likely three main characters (Could have been more, but three is a definite minimum) Each character had a personal fighter/ship, colour coded to their uniform colours (I don't think they were designed as pure fighters, but they definitely had some kind of weapons). The show took place in deep space and I don't specifically remember any kind of references to Earth. There were definitely FTL jumps, but the terminology used for the technology escapes me. There was a large ship capable of devouring asteroids/planets for some reason, likely controlled by whatever passed for the bad guys. (Young me was likely quite impressed by it) One particular scene that I have quite vividly (probably from the series premier) had them exploring an abandoned wrecked ship, exterior lights flickering over the ships name (This ship was probably very important and likely became their home base, but I don't guarantee that).   And, sadly, I think that's about all I can confidently remember.  I thank you for indulging me in my little bit of nostalgia with my childhood.


Acceleration of a ball thrown into the air

A ball sitting in a person's hand is at rest. The ball is thrown into the air. There must be some upward acceleration which is greater than the acceleration due to gravity, since in order for the ball to move, the upward force must be greater than the force of gravity. Since the mass of the ball doesn't change, the acceleration upwards must be greater than the acceleration downwards for the upward force to be greater than the downward force.  The instant the ball leaves the hand, what is its acceleration?    a. Acceleration of gravity, downward b. Upward acceleration from the throw c. Something else   If a, how it can be that the acceleration changes instantaneously to that of gravity, what happens to the acceleration from the throw?  If b, at some point the only acceleration on the ball must be from gravity (because otherwise the ball would keep going forever like a rocket), yet this means the acceleration is decreasing and at some point it will be 0. Then there is no force acting on the ball and it is moving at a constant velocity, but this doesn't make sense because the ball is certainly accelerating due to gravity.  If c, then what is really happening?  EDIT: It seems that according to the answer of another question here, "a" is correct. However, that question and its answer does not address what happens to the upward acceleration from the hand. Does it instantaneously become zero, such that the ball only has an initial velocity upward but not an initial acceleration upward?


Vertex of a pentagon-Does the algorithm always stop?

To each vertex of a pentagon,we assign an integer $x_{i}$ with sum $s=\sum x_{i}>0$. If x,y,z are the numbers assigned to 3 successive vertices and if $y<0$,then we replace $(x,y,z)$ by $(x+y,-y,y+z)$.This step is repeated as long as there is a y<0.Decide if the algorithm always stops.


Apex trigger to stop duplicate records into SF if email already exists on a person account

I have an existing trigger which converts leads into peron accounts if the company name is blank.  Trigger AutoConvert on Lead (after insert) {      LeadStatus convertStatus = [           select MasterLabel           from LeadStatus           where IsConverted = true           limit 1      ];      List<Database.LeadConvert> leadConverts = new List<Database.LeadConvert>();       for (Lead lead: Trigger.new) {           if (!lead.isConverted && lead.Company == null) {                Database.LeadConvert lc = new Database.LeadConvert();                String oppName = lead.Name;                 lc.setLeadId(lead.Id);                lc.setDoNotCreateOpportunity(true);                lc.setConvertedStatus(convertStatus.MasterLabel);                 leadConverts.add(lc);           }      }       if (!leadConverts.isEmpty()) {           List<Database.LeadConvertResult> lcr = Database.convertLead(leadConverts);      } }   I need to also write a trigger that stops records from coming into Salesforce if that email already exisits in a contact or an account (we use person accounts).  The issue is how do I get it working with the existing trigger (I need it to run before the trigger that converts it into a person account is run).   Is there a way to combine the two or add the functionality to create the record only if the email address doesn't already exist as a contact in the org?


Self complied version of GCC overwriting package installed version

I'm using debian to do most of my coding work, and I was doing a homework project that required a certain version of gcc to compile the program I was working on.  I downloaded the gcc source and compiled/installed it, but forgot to change any options, so I think it installed it to the default location, which in my case was /usr/local/bin/gcc. I wasn't really planning ahead when I did this, and when I realized I was done with the version of gcc for my homework, I didn't know how to remove it. Upon googling, I realized that this wasn't really possible, unless I used checkinstall which I didnt. Now however, because /usr/local/bin is ahead in my path, it uses my newer version of gcc to compile by default which causes problems when I try to use gdb to debug those versions of applications. I'm also worried that this will cause unwanted behavior in other applications that can screw things up.  Note: I can't just reorganize my path, because there are applications in /usr/local/bin that I want that override ones in /usr/bin  So my question is this: How do you manage self-compiled applications with packaged ones from repositories? What I mean is, what is the correct way of going about this, so that they don't conflict and one can safely be removed without screwing anything up? In terms of mixing them, how would I do something like using a self-compiled version of an application as a dependency for a packaged version? I don't think debian will automatically recognize that if I install gdb or something, that my local version of gcc will meet the criteria.  Also as a side-note: Where the heck do you install compiled applications? /usr/local/bin? /opt? /home/user/bin? /own_directory?  My apologizes if I wrote this badly or anything, I can clarify more if needed.


Where is data of Google Play Services located in device? Can I safely delete it?

Just noticed that data in internal storage for Google Play Services app grew above 100Mib, so this app is officially a space hog now. So my questions are:  What is the exact location for Google Play Services data? (for backing up) Can I safely delete Google Play Services data and let the app recreate it? What might I lose if I delete Google Play Services data unsafely?


I have this bit of code which returns an error, and I can't explain why. Basically I retrieve from GET the table and the id of the post I want to pull from database, and everything works fine as long as the table name is fixed and not :table. You can clearly see I'm new to PDO, so do you have any thoughts on where I'm doing wrong?    $pageid = $_GET["id"]; //31 $tablename = $_GET["table"]; //table_name $pdo = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password); $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $sql="SELECT * FROM :table WHERE id LIKE :pageid"; $stmt = $pdo->prepare($sql); $stmt->bindValue(':table', $tablename); $stmt->bindValue(':pageid', $pageid); $stmt->execute(); $result = $stmt->fetch(PDO::FETCH_ASSOC);   The error is the following, so appearently the table name is wrapped by ' breaking the script? That seems weird, since the :pageid doesn't have them and the code generating both is the same.       Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''table_name' WHERE id LIKE 31' at line 1' in /...   Thanks a lot for any advice


I have recently changed the title of my website and whenever I search it I get the previous one only but on search with the specific keywords change I have recently made I get the correct output which I have changed Why is that and will I get punished for this? And is it possible to remove the old one and replace it with the new one


What is the apparent viscosity in shear thinning turbulent flow through a pipe?

The explanation of shear rate in laminar flow is straightforward: We imagine small layers of fluid that glide on each other. Now, in turbulent flow, this does not work as there are no layers. If I want to know the apparent viscosity of a shear thinning (or other non-Newtonian) liquid, I need to know the shear rate. I've asked about this before , and . However, I can't solve the Navier Stokes equation, so someone has to walk me through it or present me with an answer.  Fluid may be assumed to be a power-law fluid.


How do I update the GUI from another thread?

Which is the simplest way to update a Label from another Thread?   I have a Form running on thread1, and from that I'm starting another thread (thread2).  While thread2 is processing some files I would like to update a Label on the Form with the current status of thread2's work.   How could I do that?


Prove that $p=13$, given that $(p-1)/4$ and $(p+1)/2$ are prime.

Suppose $p$ is a prime such that $(p-1)/4$ and $(p+1)/2$ are also primes. Show that $p=13$.   I thought about taking $p_1=(p-1)/4$ and $p_2=(p+1)/2$ and proving that there is only one possible case where $p_1$ and $p_2$ are primes simultaneously. Well that is, obviously, the intention of the question. But, I'm not able to do so.  Please Help!!


"for items in dict" displaying in random order?

So I'm pretty new to programming, and I'm working on a small text based game for practice. Anyways, here's my problem.      x=1     for items in hero.basics:         print(x, ". ", items, sep = "")         x += 1   and the dictionary is,  self.basics    = {"Attack" : self.attack, "Potion" : self.potion}   So I need it to display in the same order as the actual dictionary, but it always displays randomly.  Any suggestions?


How to disable two-fingers/right-click in touchpad?

I would like to disable the function right-click when tapping the touchpad with two fingers, because it is always interfering with the two-fingers/scrolling function. I also would like to maintain the function left-click when double tapping with one finger. Thanks for the help.


Proverb, quote or phrase which convey that the approach, ideas that are meant to improve the system or process are the onces which fail them

I am looking for a proverb, quote or phrase describing the  processes (or structures or ideas) which are supposed to bring in efficiency, enhance the gaps and increases in-efficiencies, but instead prove to be the reason for the decline of a system. Explanation with example  Big external agencies were hired in order to define the efficient way to improve the system. However, these agencies do not understand the system and do all sorts of trial and error methods to innovate the process for years, yet not only do they waste company resources but are paid a ton of money so as to fix what can be done internally.


The months shown on the reputation chart are all next to each other, no spaces

I was just checking on my account since I saw an e-mail notifying me on the change in reputation on questions, and I noticed this:        I recognize that this is a bug, and I want to shed light onto it, but I am also wondering how this might have occurred.


To prove  $ \tan(A) + 2 \tan(2A) +4\tan4A + 8 \cot8A =\cot(A) $.  I tried to convert $\tan(4A)$ and $ \tan(8A)$ to $\tan(A$) and tried putting in L.H.S but it becomes a mess. Is there a easy and also intuitive  way to do this?  Thanks


which one to choose in supervised learning?

Generally, in supervised learning, we have many algorithms. But I am confused to choose which one is good for a problem. how to find that linear models can be used in this case or trees or SVM or KNN in particular case??


Evaluate $ \int_0^\infty \cos(x)/\cosh(x) dx $

I need to evaluate $$\int_0^\infty \frac{\cos(x)}{\cosh(x)} dx $$  through Residue Theory, but it has an infinite number of poles in x=(2n+1)pi/2, I couldn't find the way to the solution that is $$\frac{\pi\ }{2 \cosh \ (\pi\ /2)}.$$  I tried also the Method of the Fourier Integral, but couldn't find the answer too. I'm in this question for over 1.5h and  have a test tomorrow, can someone help me?


Why didn't the Tesseract get transported with Red Skull?

At the end of Captain America: The First Avenger Red Skull disappears and it was later discovered that he was transported by the Tesseract. In other circumstances like when Thor took Loki to Asgard at the end of The Avengers, the Tesseract went with them. But in case of Red Skull he was transported but the Tesseract didn't go with him. Why did this happen?


"Decryption Exception" errors on Named Credential

I have callouts that use a Named Credential and a Custom Oauth2 Auth Provider fail with this error response:     Invalid parameter value "[hidden]" for parameter "Decryption   Exception"   A similar error is sometimes shown when I resave the Named Credential     Unable to Access Page The value of the "Decryption Exception"   parameter contains a character that is not allowed or the value   exceeds the maximum allowed length. Remove the character from the   parameter value or reduce the value length and resubmit. If the error   still persists, report it to our Customer Support team. Provide the   URL of the page you were requesting as well as any other related   information.   When I simulate the Oauth Flow and Callout in Postman it always works. I'm quite sure this is a Platform bug.


Loading a java array with rs.next() throws null pointer error no matter what. Checked with console

I have a very simple table.  ╔════╦═══════╗ ║ id ║ title ║ ╠════╬═══════╣ ║ 1  ║ cow   ║ ║ 2  ║ duck  ║ ╚════╩═══════╝   ID is INT  TITLE is TEXT  I´m trying to fill an array with these two registers.  collection class has a constructor of (int,String)  My code:  collection[] co=null;  String query="SELECT * FROM collection";    ps=conn.prepareStatement(query);    rs=ps.executeQuery();    int counter=0;         while(rs.next()) {             co[counter]=new colleccion(rs.getInt("id"),rs.getString("title"));             System.out.println(rs.getInt("id"));             System.out.println(rs.getString("title"));             counter++;         }   System.out.println works ok, the values are showed correctly. But it throws an exception as soon as it reaches the array line.  Also tried with column numbers (1 and 2), but it is the same.  Help please.


Find largest value, Nth largest and others before it? (while ignoring duplicates)

So I have a column say A that looks like this:  I 15 0 3 15 M 8 0 8 21 Q 0 5 0 0   I can find the largest value with =MAX(A1:A100) I can find the smallest value with =SMALL(A1:A100,1)  How do i find the one before the largest and the one before that. I can use Large to call the Nth value, but then how do I know how many N values the function counts so I can know what positions it uses refer to the last 3 (largest and the 2 before)?  Ignoring duplicates - in the example the largest is 21, the one before is 15 and before that is 8. If I do =LARGE(A1:A100,3) it will return 15 as there is two of em in the column. And I'm looking for the 8 as the third largest value.  Below you will find the helpful folks of the Internet to have provided a PivotTable, an Array Formula solution, and I was finally able to do a simple formula one.   You can provide vba for the job should you insist we have everything, otherwise there is enough already.


None of the answers to this question have even vaguely answered it but have gone off on tangents instead.  It has nothing to do with the airline, whether it is accepted or not depends upon the airport, not the airline.  But that is besides the point, the question is how do you physically add a boarding pass to Apple Wallet.  American Airlines sends an email to you which contains a link to your boarding pass.  American further advises you to add the pass, that appears after you have followed that link, to your Apple Wallet. The procedure should be to open Wallet, click on the + sign in the top right corner and then position the boarding pass within the box in Wallet until Wallet clicks and records the boarding pass. Unfortunately, nothing seems to happen. You never get to that "click" and the question is why?  I agree with the person who posted this question earlier: it should be easy, so why isn't it?


Python Add In Change tab in Table of Contents

I'm working on an add in that generates new structures for an addressing system. The tool is working well, but as it runs, at some point it changes tabs in the Table of Contents to the "List By Source" tab. I'm guessing it does this either when I add temporary tables or shapefiles.   The fact that it changes tabs is not a problem, but I would like for the tool to leave the user in the TOC tab "List By Drawing Order" when it is finished.   Is there any way for a python code to change tabs in the TOC ?


I am using Dell vostro 1550 laptop. It has intel i3 2nd gen processor and 2gb RAM and running Windows 7 64 bit. Can I install Ubuntu 14.04 LTS 64 bit on my laptop?


I want to make a long shadow just like in this image.  I can create this shadow with shapes and by deleting the unwanted shadows after rasterizing the layer. But it's not very reusable. I can't resize the layer after rasterizing it.  Is there any easy way to make a long shadow like in the image below?


Can you please explain in detail why I "skip" the article before Central Park, "skip" the article before St. Peter's Cathedral and "keep" the article "the" before the Chrysler Building, in the following sentence?   I am an ESL teacher/English Teacher who teaches adults.and it seems this maybe has to do with the context of listing places? I don't know why I am putting the 'the' in at the end and not in the rest of the sentence? I don't know how to explain this one.   We can see(no article) Central Park, (no article) St. Peter's Cathedral, and the Chrysler Building from our room.   Warmly, Jules


Command for Matrix with elements besides it

I'm trying to make a new command in LaTeX to put a matrix like that  and i expect that at the end it stands something like this: \newmatrixcommand{#1}{#2}{#3}{#4}. I got close using a composition of commands as follows \begin{document}    \newenvironment{spmatrix}[1] {\def\mysubscript{#1}\mathop\bgroup\begin{pmatrix}} {\end{pmatrix}\egroup_{\textstyle\mathstrut\mysubscript}}  \begin{eqnarray} \begin{matrix} a_{1j}\\  a_{2j}\\ a_{3j} \end{matrix} \begin{spmatrix}{\;a_{i1} \;\;\; a_{i2} \;\;\; a_{i3}} a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33} \end{spmatrix} \begin{matrix} a_{1j}\\ a_{2j}\\ a_{3j} \end{matrix} \end{eqnarray}  That is the result  even trying to change anyhow, i can't get what i supposed to. Any help, will be welcome.


I live in the house next to/close to the cinema.    I live in the house that is next to/close to the cinema.         I go to the school in front of/behind my house.    I go to the school that is in front of/behind my house.         I work at a supermarket far from my place.    I work at a supermarket that is far away from my place.         My friend lives in the apartment block opposite mine.    My friend lives in the apartment block that is opposite mine.         Which ones are correct and make sense? Are there any rules or guidelines for this kind of structure?


Ask question post button remains disabled

I've noticed this twice in the last ~2 weeks or so. The "post your question" button can remain disabled for some reason even when your question is shown as "ready to publish". I.e., you've gotten to the "review" page after the initial edit. If I remember correctly, one case was on Stack Overflow, and the other was on . I'm not sure what exact scenario leads up to this. I haven't paid attention to the button until the last step when I'm ready to click it. The workaround has been to reload the page. (I copied my content for safe-keeping first.) This works, and the button then shows up as active. Afterwards, however, on both occasions, it forced me through the "are you a human" verification.  Update - this question itself did not exhibit this, nor did it do the .  Update - I'm using Chrome on Windows and am not sure what version it was when this happened.  It has  installed, but there aren't any scripts for any Stack Exchange sites.  It has  installed.  The virus scanner on the PC I probably was using was


It is given that, $x+y+z=3\quad 0\le x, y, z \le 2$ and we are to maximise $x^3+y^3+z^3$.   My attempt : if we define $f(x, y, z) =x^3+y^3 +z^3$ with $x+y+z=3$ it can be shown that,   $f(x+z, y, 0)-f(x,y,z)=3xz(x+z)\ge 0$ and thus $f(x, y, z) \le f(x+z, y, 0)$. This implies that $f$ attains it's maximum whenever $z=0$. (Is this conclusion correct? I have doubt here).   So the problem reduces to maximise $f(x, y, 0)$ which again can be shown that $f(x, y, 0)\le f(x, 2x,0)$ and this completes the proof with maximum of $9$ and equality at $(1,2,0)$ and it's permutations.   Is it correct? I strongly believe even it might have faults there must be a similar way and I might have made mistakes. Every help is appreciated


Are "This answer should be marked as accepted" comments not constructive?

Occasionally I come across great answers that aren't marked as accepted. They are commonly accompanied by the comment:     "This should really be marked as accepted."   ()  In my opinion, the upvotes on the answer itself indicate the quality of the answer, and any commenting to the effect of...     "This should be accepted"      "This is the better answer"      "This works better than the accepted answer"   ... is no better than a longer way of adding this comment:     "+1"   Which makes upvotes on said comment even more ridiculous, does it not?    In most cases, a highly upvoted comment indicates extra information relevant to the answer. This expectation makes comments like those above rather distracting and, dare I say, detract from the quality of the presented answer.  Can you provide a counter-discussion exploring the positive value of such comments? Or should they be flagged "not constructive" without reservation?


Can two persons sharing a name travel one-way each on a return ticket?

I would like to know if my brother can fly by United Airlines from USA to El Salvador, and my father, from El Salvador to USA using the same round trip ticket, both of them have the same name.


Example of two prime ideals whose intersection of the squares not equal to the square of the intersection

In  the OP raised the following question:   Let $R$ be a commutative noetherian ring and $\mathfrak p,\mathfrak q \in \operatorname{Spec}(R)$. Is it true that $(\mathfrak p\cap \mathfrak q)^2=\mathfrak p^2 \cap \mathfrak q^2$?  Obviously, we always have $(\mathfrak p\cap \mathfrak q)^2 \subseteq \mathfrak p^2 \cap \mathfrak q^2$ and there is no reason to think that, in general, the converse holds.   What remained unsolved in that topic is to     Give an example of prime ideals $\mathfrak p,\mathfrak q$ (in a noetherian ring) such that $$(\mathfrak p\cap \mathfrak q)^2 \neq \mathfrak p^2 \cap \mathfrak q^2.$$   Edit. It would be nice to have such an example for $R$ a noetherian integral domain.


I'm trying to create a form that verifies that an email address has been entered. Not necessarily check its validity but basically sakjfsfksldjf@email.com. I was wondering how to go about doing it in PURE JavaScript and no RegEx.       <!DOCTYPE html>      <html lang="en" xmlns="http://www.w3.org/1999/xhtml">     <head>         <meta charset="utf-8" />         <title>Test File</title>     </head>         <script>             function submitForms() {                 email_format = document.getElementById('email_input')       // want to return T or F                 if (email_format) {                     //print email successful                 }                 else {                    //print error message                 }                  </script>      <body>          <form>             Email:                         <input type ="email" id ="email_input" />         </form>          <button type = "button" onclick = "submitForms;"> Submit All!         </button>     </body>     </html>


How can I send commands to specific terminal windows?

I'd like to write a script for opening multiple programs (servers) simultanously in separate terminals - doesn't matter which one - and assign different commands to different terminals with commands "landing" inside the correct terminal. Is this possible? Maybe, something like this:    open terminal1  open terminal2 //simultanously with 1. command1 //execute in terminal1 without opening a new terminal window command2 //execute in terminal2 without opening a new terminal window ...   Can I somehow label terminal windows so commands are executed inside correct terminal?  I'd also like to watch all terminals while their programs are running - my programs have an argument for printing trace/debug to terminal. So I'd like to see what messages are exchanged between them.  NOTE: I'm less concerned about security of exchanged data since this script should serve as a "simulation". I've configured each server to run from an allocated port on localhost.


How do you make people drop extra items on death?

As seen in this video: (Skip to 5:53)  When a player is slain, they drop an Enchanting Table on top of their inventory.  How was this achieved and how can I build a system (using command blocks) that does that? Come to think of it, what happens to a player's location when he/she dies? Does it reset to the spawnpoint? Stay the same (where they died) until they respawn? Or becomes a null value until they respawn?


What software is in the Canonical Partners repository?

I'd please like to know what software (or see the list) is in that repository. I enabled it and of course let the system update the package list.. but I can't seem to find both Chrome nor Skype after it (using Ubuntu Software).  Any idea??? Shouldn't it be in a wiki or the official documentation? Thanks :)


How to install google chrome browser on a i386 (32 bit) ubuntu 14.04?

I tried to install using following command for 32-bit system.  wget https://dl.google.com/linux/direct/google-chrome-stable_current_i386.deb   But I got an error:  Resolving dl.google.com (dl.google.com)... 216.58.199.174, 2404:6800:4009:807::200e Connecting to dl.google.com (dl.google.com)|216.58.199.174|:443... connected. HTTP request sent, awaiting response... 404 Not Found 2016-06-30 20:05:59 ERROR 404: Not Found.


Mesh sticking to edges when using subdivision surface

Amateur with Blender here, using 2.8, having an issue with the Subdivision surface modifier. I have a very simple shape here and I'm trying to extrude while using the modifier, I have this one part of the mesh that sticks to the edges of the model.    I've tried everything I could think even, I've even deleted all the vertices in that area and rebuilt it from scratch and that darn thing just reappears. If I delete all the edges and then just fill in the new face, it'll just move to the next edge down. I definitely don't have any overlapping points.


A  has snapped: is there any reason why it can not be bridged via soldering or a butt splice? Kenmore Model 110.66642500


Why do some links to questions expand to reveal the title, and others do not?

First of all apologies:  Sorry for picking on this particular "badges" question, as an example, it was chosen at random. Sorry for the confused nature of this post - it is a bit difficult to illustrate the issue, and I have tried the best I can, using code formatting and screen shots.   The issue Consider the rendering of this URL: https://meta.stackexchange.com/questions/171136/why-do-some-badges-appear-white-in-color-and-others-are-dark  which, in the actual question text that the reader sees, appears like this:  or in screenshot form:    Why is it that some links to questions resolve themselves, to show the actual text of the question, rather than the URL, as the link above has, and others do not? When they do not, it is then necessary to add the link, either using the link button in the editor, like so: [Why do some badges appear white in color and others are dark?][1]    [1]: https://meta.stackexchange.com/questions/171136/why-do-some-badges-appear-white-in-color-and-others-are-dark  or using the "inline" method, like so: [Why do some badges appear white in color and others are dark?](https://meta.stackexchange.com/questions/171136/why-do-some-badges-appear-white-in-color-and-others-are-dark)   A visual experiment A simple test, that I have just performed, is with the link https://arduino.stackexchange.com/questions/11893/how-does-coordinator-xbee-receive-data-from-router/  Here on SE Meta, it resolves correctly:  or in image (screenshot) form:    However, if I do the same on SE Robotics, which is, currently, in beta, I get the URL, not the resolved text:    I have noticed this a lot, sometimes it resolves itself, and other times not. I work on SE beta sites a lot - probably 70% of my time is on beta sites, 30% on fully fledged SE sites. Now, after doing this test, as the link itself is to a beta site (Arduino is currently in beta), it is not the link to the site which is to blame. I am starting to think that it is beta sites themselves that can not resolve the links, that is to say, if a link is posted on a beta site, then it will not resolve itself.  Footnote Please note that I am not referring to modified links, for example, links that additionally point to specific answers or comments within the original post, as these will, understandably, not auto-resolve: https://meta.stackexchange.com/questions/171136/why-do-some-badges-appear-white-in-color-and-others-are-dark#answer-171137   https://meta.stackexchange.com/questions/171136/why-do-some-badges-appear-white-in-color-and-others-are-dark#comment-506438   Nor am I referring to these types of question URLs: https://skeptics.stackexchange.com/questions/8614/are-electronic-cigarettes-a-healthier-alternative-to-regular-cigarettes/15492#15492  which do not resolve correctly, either:  To be honest I don't understand why they exist in this format, when clicking on the actual question title goes to this: https://skeptics.stackexchange.com/questions/8614/are-electronic-cigarettes-a-healthier-alternative-to-regular-cigarettes  but that is a separate issue, that I don't wish to address here.  Addendum Whoops! Obviously, the examples in my footnote do render themselves correct, sometimes.... So, https://skeptics.stackexchange.com/questions/8614/are-electronic-cigarettes-a-healthier-alternative-to-regular-cigarettes/15492#15492  does resolve itself, on SE Meta. However, why then, on SE Workplace, which is not a beta, in one of the answers to  does the URL not resolve itself? See screenshot:


I would like to revisit and re-do certain one-off events in this game such as Eventide Island. There's probably a save file where I haven't done Eventide yet - what will happen if I load that? Will the game keep my newest save files intact, so that I can resume normal play after a short time travel?  I assume it does, would be pretty awful if it somehow automatically overwrote manual saves - but I wanna check to be sure.


Use nameof() to access parent object name

I have an extension method which takes a parameter.  Inside the extension method I want to get access to the name of the object which was passed in.  static MyObject Add<T>(this MyObject myObj, T value) {     // MyObject is dictionary<string, object> for simple example     myObj.Add(nameof(value), value);     return myObj; }  void run() {   var anotherObject = new AnotherObject() { Name = "Bob" };   var myObject = new MyObject().Add(anotherObject.Field); }   When this executes it puts "value", "Bob" whereas i want it to put "Name", "Bob" in the dictionary.  Is this possible using the nameof() function or do I need to re-think the logic?  The only thing i can come up with to preserve the general idea is:  static MyObject Add<T>(this MyObject myObj, string name, T value)...  myObject.Add(nameOf(anotherObject.Field), anotherObject.Field);   I didn't like having to repeat the field definition.


Getting a Null Pointer Exception when trying to add to an ArrayList in Java

I am trying to add a new instance to the Class User to an ArrayList of User. Whenever I run my program however, I keep getting a Null Pointer Exception. I've looked up similar issues on this site but it seems like most problems arise when the ArrayList is never established. However, as you can see from the code below, I establish my list at the top. Are there any other reasons this exception could be thrown when adding to the list? import java.util.ArrayList;  public class Users {     private static Users users;     private ArrayList<User> userList = new ArrayList<User>();      private Users() {         userList = DataLoader.loadUsers();      }      public static Users getInstance() {         if (users == null) {             users = new Users();         }         return users;     }      public ArrayList<User> getUsers() {         return userList;     }      //add get user by ID     public boolean addUser(int userID, String password) {         if(haveUser(userID, password)) {             return false;         }         User user = new User(userID, password);         System.out.println(user.toString());  // I added this to make sure my parameters are being passed in correctly. They are.         userList.add(user);  // This is the line where the NullPointerException is being thrown.         return true;     }      public boolean haveUser(int userID, String password) {         if (userList == null) {             return false;         }         for (User user : userList) {             if (user.getUserID() == userID && user.getPassword().equals(password)) {                 return true;             }         }         return false;     }


Increase Plot Size in Python with subplot

I want to resize the plots from this code but i don't know how to.  this code results plots but so tiny..  plt.style.use('ggplot')  plt.subplot(3, 2, 1)   plt.plot(raw_turen['ABJ'], color='blue') plt.title('ABJ Turen')  plt.subplot(3, 2, 2) plt.plot(raw_gondanglegi['ABJ'], color='green') plt.title('ABJ Gondanglegi')  plt.subplot(3, 2, 3) plt.plot(raw_donomulyo['ABJ'], color='black') plt.title('ABJ Donomulyo')  plt.subplot(3, 2, 4) plt.plot(raw_kepanjen['ABJ'], color='red') plt.title('ABJ Kepanjen')  plt.subplot(3, 2, 5) plt.plot(raw_bululawang['ABJ'], color='magenta') plt.title('ABJ Bululawang')  # Improve spacing between subplots and display them plt.tight_layout() plt.show()   this is the result :


Any way to import-export-migrate-save-restore a maintenance plan without having SSIS installed (and running)?

I am having dozens of MSSQL Servers 2012 R2 on Windows Server 2008 R2 with similar setup, configuration (in virtual machines) in production.  Neither has SSIS installed.   I have to similarly maintain (migrate, restore) the same maintenance plans on all of dozens servers    Any way to import-export-migrate-save-restore maintenance plans without having SQL Server Integration Service (SSIS) and Data Tools (BIDS) installed (and running)? Though I can stage a separate server machine for them    Saw  but still uncertain


Can I use Weight Paint to Control Animation Properties?

I'm thinking weight paint but maybe I mean Dynamic Paint or even something else I'm unaware of.  I have cell fractured a long thin cylinder which I am dropping onto a plane using Blender 2.71 Render (not BGE).  It has been rotated a little so that its contact with the plane starts at the lowest shard and works its way to the top.  Of course, the whole thing simply falls apart on first contact.  So, I use rigid body constraints and this works fine keeping it together.  What I want, however, is a progressive shatter as the cylinder shards come into contact.  In other words, I want the shards which have not yet reached the plane to stay intact. Keyframing this one shard at a time is tedious, prone to error, and all but impossible when there are hundreds of shards.  Can I use weight paint or anything else to control the enable function (or any other property or function) associated with the constraints to switch from enabled to not enabled as a function of time (or frame number)(in other words, as a function of color)?


Prepared statements with many parameters is slow

I have an application written in PHP with Laravel that regularly prepares and executes statements like this:     -- All parameters are varchar(10)    SELECT c1, c2, c3, c4       from MyBigTable      where is_active = 1        and c1 in (@P1, @P2, @P3, @P4 ... @P250)        AND c2 is not NULL   Users have a big data grid, and they can select many rows (there is even a button to select 'ALL'). If they select 250 rows, this statement is what happens. But it takes more than one minute to run, which is unacceptable.  Table MyBigTable has about 10 millions rows. The estimated execution plan shows that 100% of time is spent on an "index seek, non-clustered". From this I deduce that the situation can not be improved using indexes, and that the only issue is in the use of prepared statements. (If you think I am wrong, just let me know). Moreover, I understand that these prepared statements are prepared, used once and discarded, so I don't think they are really beneficial.  What recommendation should I give to the developers?  Should I just tell them to stop using prepared statements, and hardcode the 250 values in the query?  Or should I give them some workaround, like the use of temporary tables (make a temporary table, insert 250 values, then make a query on MyBigTable JOINed with temp)?  Or any other idea?  EDIT: execution plan


Say I have an array of key-value pairs with non-numerical keys. If I am going to be using those keys as values in an SQL INSERT statement, is it important to sanitize them as well?  Something like:  $food = array('fruit'=>'apple', 'veggie'=>'tomato', 'bread'=>'wheat'); foreach($food as $foodType => $nameOfFood) {     $nameOfFood = stripslashes($nameOfFood);     $foodType = stripslashes($foodType); //Is this necessary?     $query = "INSERT INTO Foods(FoodType, NameOfFood) VALUES ($foodType, $nameOfFood)";     // Execute query }   If the $food array was populated through a POST statement, would sanitizing the keys be a concern?


I'm working on game, using LibGDX and have some problems with Input Processor. Wnen I launch my game and press Right button it crashes with NullPointerException  @Override public boolean keyDown(int keycode) {     if (keycode == Input.Keys.RIGHT && player.b2body.getLinearVelocity().x <=0.5) {         player.b2body.applyLinearImpulse(new Vector2(0.1f, 0), player.b2body.getWorldCenter(),true);         return true;     }     return false; }    public  void update (float dt) {           world.step(1/10f,6,2);         player.update(dt);        // handleInput(dt);          MyInputProcessor inputProcessor = new MyInputProcessor();         Gdx.input.setInputProcessor(inputProcessor);         if(player.b2body.getPosition().x>=SonicZP.V_WIDTH/2/SonicZP.PPM)         gamecam.position.x = player.b2body.getPosition().x;          if(player.b2body.getPosition().y>=SonicZP.V_HEIGHT/2/SonicZP.PPM)             gamecam.position.y = player.b2body.getPosition().y;         gamecam.update();                renderer.setView(gamecam);     }


Concatenating strings in python without spaces

How can I print my strings so that there are no spaces between each output.  name_input = str(input("Please enter your name")) name_input = name_input.strip() name_input = name_input.lower() first_letter = name_input[0] first_space = name_input.find(" ") last_name = name_input[first_space:] last_name_3 = last_name[0:4] random_number = random.randrange(0,999) print("*********************************************") print("Username Generator") print("*********************************************") print(first_letter + last_name_3, random_number)`   Incorrect output: b fir 723  what I require: bfir723


$24~$ divides $~p^2 -q^2$, where $~p~$ and $~q~$ are primes greater than $~5$

I know this question is answered, here         httpsss://math.stackexchange.com/questions/507451/suppose-that-p-%E2%89%A5-q-%E2%89%A5-5-are-both-prime-numbers-prove-that-24-divides-p2  But when I was doing the question ,I thought that  "Can I make difference of square of $2$ primes a product which is divisible by $4!$ "  While doing it, some examples were just trying to show me something but I don't know what the examples are shown in the pic.


I created a very long booklet in Indesign which I created in 4000 x 3000 pixels.  I am trying to reduce it by half in pixels so that the size of the file comes down dramatically as I am trying to get it into a size that looks fine and I can email it. At the moment it is 44mb.  If I change the JPG to lower it effects banding on graduated colour images so I'd prefer to reduce the pixel size instead so that I dont get the banding.  I have been trying to fiddle around with alternative layout but it seems to screw it all up.  Many thanks for any help :)


Resetting a dictionary in TexStudio/MikTeX

I accidentally "always ignore"d a wrong wrong word. How do I undo it and make the old dictionary clean again?


Riemannian Manifolds with $n(n+1)/2$ dimensional symmetry group

Given a $n$-dimensional connected Riemannian manifold $(M,g)$, its symmetry group $G$ can be considered as a subbundle of orthonormal frame bundle of $M$ (which I call $F_OM$), yielding: $$\dim G\le \dim F_OM=\dim M +\dim O(n)={n+n(n-1)\over 2}=\frac{n(n+1)}{2}$$ (Here the embedding $\phi:G \hookrightarrow F_OM$ is defined by singling out an arbitrary point $p \in M$ and orthonormal frame $(v_1,...,v_n) \in F_{O,p} M$ and defining $\phi: g \mapsto (gp,g_*v_1,...,g_*v_n)$. However, it takes some work to verify that this map is indeed injective.)  These considerations made me wonder which manifolds have a maximally large symmetry group, i.e. which $M$ do satisfy $\dim G= \frac{n(n+1)}{2}$. Of, course $\Bbb R^n,\Bbb S^n$ and $\Bbb H^n$ have got this property, but are there any other exotic examples?   (Some thoughts of mine on this problem: One can see that $M$ is homogenuous and isotropic. Each stabiliser of a point has to be isomorphic to either $SO(n)$ or $O(n)$. In particular, $M$ has constant curvature, which implies that $M$ has to be one of $\Bbb R^n,\Bbb S^n$ and $\Bbb H^n$ if $M$ is complete and simply-connected.)


Prove that this series converges: ${(\frac{n}{n+1}})^{n^2}$

How to prove that this series converges: $\sum_{n = 1}^{\infty}{({\frac{n}{n+1}})^{n^2}}$ ?  I tried root test, ratio test, comparison test, Cauchy condensation test, but none works. Any hints?


What are the main purposes to ask someone 'Where do you work?' apart from to find out the type of place he or she works in?  I can answer:     I work in a shop.   I work in a hospital.   I work in an office.   But what other things can (or should) I use as a reply to this question?    Extra question:  sometimes I see     I work at a shop.    I work at a hospital.    I work at an office.   What's the difference between 'at' and 'in' in this case?


How to improve this simple neural network in keras for non-linear regression?

I am training a simple neural network in keras to fit my non-linear thermodynamic equation of state. I use backpropagation and stochastic gradient. The network approximates the equation of state but is far from being good.  I added the code here:  import numpy as np import CoolProp.CoolProp as CP  import matplotlib.pyplot as plt  from keras.models import Sequential from keras.layers.core import Dense from keras.optimizers import SGD  # vector length nT = 20000 nP = 100 T_min = 50 T_max = 250  fluid = 'nitrogen'  # get critical pressure p_c = CP.PropsSI(fluid,'pcrit')  p_vec = np.linspace(1,3,nP) p_vec = (p_vec)*p_c  T_vec = np.zeros((nT)) T_vec[:] = np.linspace(T_min, T_max, nT)  rho_vec = np.zeros((nT))  print('Generate data ...') for i in range(0,nT):     rho_vec[i] = CP.PropsSI('D','T',T_vec[i],'P',1.1*p_c,fluid)  # normalize T_max = max(T_vec) rho_max = max(rho_vec)  T_norm = T_vec/T_max rho_norm = rho_vec/rho_max   print('set up ANN') ###################### model = Sequential() model.add(Dense(200, activation='relu', input_dim=1, init='uniform')) model.add(Dense(100, activation='relu', init='uniform')) model.add(Dense(output_dim=1, activation='linear'))  sgd = SGD(lr=0.05, decay=1e-6, momentum=0.9, nesterov=False) model.compile(loss='mean_squared_error', optimizer='sgd', metrics=['accuracy'])  # fit the model history = model.fit(T_norm,rho_norm,epochs=20,batch_size=10,validation_split=0.3,shuffle=True)  predict = model.predict(T_norm,batch_size=10)  plt.plot(predict) plt.plot(rho_norm) plt.show()   The outcome is the following (blue is the ANN prediction):    However, when I use the same model, with the same architecture on a sine it actually predicts quite well (blue again the ANN):   How can I tune my model so that it accurately predicts my thermodynamic equation of state?


How concept of spin comes theoretically?

Spin comes from Dirac's theory. Does it only comes from the fact that relativistic Dirac equation is Lorentz invariant?


Derivative with Respect to Symmetric Tensor

If you have a Lorentz tensor $T$ with components $T_{\mu\nu}$, it seems clear that $$ \frac{\partial T_{\mu\nu}}{\partial T_{\rho\sigma}} = \delta^\rho_\mu \delta^\sigma_\nu. \tag{1} $$ However, if $T$ is symmetric, so $T_{\mu\nu} = T_{\mu\nu}$, there are two ways this derivative could be nonzero, so $$ \frac{\partial T_{\mu\nu}}{\partial T_{\rho\sigma}} = \delta^\rho_\mu \delta^\sigma_\nu + \delta^\sigma_\mu \delta^\rho_\nu. \tag{2} $$ Does this mean the first expression is wrong? It seems that some information is lost if one naively uses the first expression with a symmetric matrix, because the result lacks the symmetry in $\mu$ and $\nu$ and in $\rho$ and $\sigma$ that the derivative must have.  Additionally, should there be a factor of $\frac{1}{2}$? If one sets $\mu = \nu = \rho = \sigma$, then the second expression yields 2. However, introducing this factor seems to then yield $\frac{1}{2}$ when $\mu = \rho$ and $\nu = \sigma$ but $\mu \neq \sigma$, when it should yield 1. What am I missing?


I am currently farming Heart Scales from Luvdiscs. Looking at the fact I am not moving, but just fishing then thieving with Malamar, I was wondering if I could possibly get a Shiny out of it. What will interrupt my "Chain Fishing"? Does going to my inventory to take the heart scale cancel it? What about using a PP O-Power?


Does someone know if the login's system for the chat is somehow broken? The link  chat.meta.stackexchange.com gives me an error page.    If I try to bypass that error and go to the Tavern chat room directly, I get asked to add a login method to my account, as illustrated there;    And if I click To continue without adding a new way to log in, click here, the system opens the chat room and tell me I'm not logged in. I can't login, as if I click login again I'm still asked to add a log in method.


With recent DDoS incidents related to wikileaks, I can't help but feel that pretty much all sites online are very vulnerable to such attacks. Visa, MasterCard (to name a few) have shut down because of this.  So my questions are:    Is DDoS such a powerful form of attack? What can a company do to deal with this situation?    EDIT:  I think I might have phrased my question too "n00bishly". I know what a DDoS is (from wikipedia and other sites).   My real question is: Why are those Big companies NOT applying anti-DDOS techniques? Don't tell me that Paypal and MasterCard are not afraid of service down or attacks. I have looked over the cost of some of these solutions, but they don't seem that expensive at all compared to how much Paypal or VISA makes a year. The real question is why are they so unprepared? ( Or is the scale of the DDoS that much bigger than what has been expected?)


I have a problem with my project on Android Studio. Every time I run the app, it starts up perfectly normal, no build errors at all, however, upon clicking a button on the Main Activity to go to another activity, the app stops. I have checked Logcat for the issue and it states that -  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.opendayapp.openday/com.opendayapp.openday.FAQ}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference  at com.opendayapp.openday.FAQ.configureContactButton(FAQ.java:55) at com.opendayapp.openday.FAQ.onCreate(FAQ.java:20)   Here is some code from that project that Logcat has checked that might have an issue with it   Public Class  public class FAQ extends AppCompatActivity {       WebView webView;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_faq);         configureHomeButton();         configureContactButton();          webView = (WebView) findViewById(R.id.webViewInformation);          WebSettings webSettings = webView.getSettings();         webSettings.setBuiltInZoomControls(true);         //webSettings.setJavaScriptEnabled(true);          webView.setWebViewClient(new WebViewClient());         webView.loadUrl("file://asset/information.html");     }   Here's another part of the code that Logcat highlighted to have an issue with          Button contactButton = (Button) findViewById(R.id.btnContact);         contactButton.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {             Intent i2 = new Intent(FAQ.this, Contact.class);             startActivity(i2);             overridePendingTransition(R.anim.slide_in_right, R.anim.slide_in_left);             }         });     }    Is there a fix for this, as I am stuck for a way to resolve this. Many feedback and criticism will be very helpful for future references   Thanks in advance


Prohibit indexing aliases and original paths for search engines

For the same website two domains are used.  Would onedomain.com/node/100 be indexed by search engines for the alias onedomain.com/article/100 which is disallowed to be indexed by search engines in robots.txt? (onedomain.com/node/100 = onedomain.com/article/100)


Should I install DirectX 9.0(c) on my Windows 7 RTM machine?

I've just installed a new game on my Windows 7 RTM machine. The game is asking me to install DirectX 9.0(c). I said 'NO' because my machine has DirectX 11 (confirmed with dxdiag). When I run the game, an error occurs informing me that d3dx9_39.dll is missing.  Is Windows 7 DirectX backwards-compatible?


If $H$ and $K$ are subgroups of $G$, and $K$ is normal, then $HK$ is a subgroup of $G$

$HK$ is the set of all products $hk$ where $h \in H$ and $k \in K$. Quotient groups are the next chapter in my textbook, so please avoid using them.  I figured out inverse-closure: $h^{-1}\in H$, $k^{-1}\in K$,  $h^{-1}k^{-1}\in HK$  $h^{-1}k^{-1} = (kh)^{-1}$  RHS $= (hk^{'}h^{-1}h)^{-1}$  because $k$ is normal and $k = gk^{'}g^{-1}$ for any $g \in G$  RHS $=(hk^{'})^{-1}$ for every $h\in H$ and $k^{'}\in K$ possible.  Operation-closure is giving me trouble. I don't know how to prove every $hkh^{'}k^{'}\in HK$  I suspect this might be a bad place to start.


Problem Denote by $\lambda_n$ the Lebesgue measure on $\mathbb {R}^n$. Let $h \in \mathbb {R}_{>0}$. Let $A \subset \mathbb {R}^{n-1}$ be Lebesgue-measurable with finite measure. Define the cone $C(A,h)$ as the union of all straight lines connecting a point in $A \times\{0\}$ with the point $(0, h) \in \mathbb {R}^{n-1} \times \mathbb{R}$. Prove that $\lambda_n (C(A,h))=\frac{h}{n}\cdot \lambda_{n-1}(A)$. Where I struggle  Assuming that $C(A,h)$ is (Lebesgue-)measurable, this is a simple application of Fubini. How Fubini is used is all clear to me.  However, why is $C(A,h)$ measurable? It seems one could roughly argue as follows: As $A$ and $[0,h]$  are measurable so is $A \times [0,h]$. As $A \times [0,h]$ is measurable it is the union of a null set and a Borel set. $C(A,h)$ is the image of $A \times [0,h]$ under a certain diffeomorphism (c.f. ). Diffeomorphisms map null sets to null sets, and Borel sets to Borel sets. Hence, $C(A,h)$ is (as a finite union of measurable sets) measurable.  Unfortunately, I am not allowed to use the above properties of diffeomorphisms. What are other ways to prove the claim? Please only give a hint to set me thinking.


I came across this sentence,  "Modi understands only one alphabet, and that is the capital I"  in the Indian writer Dr. Shashi Tharoor's recently published book "The Paradoxical Prime Minister". When I looked the word 'alphabet' up in dictionaries, I get the definition as 'a set of letters or symbols in a fixed order used to represent the basic set of speech sounds of a language, especially the set of letters from A to Z'. () Why was 'alphabet' used here?


How to access fields from the inner join

I need to access the fields from the nested Select statement.  Here is the code  Select Name, id, (SELECT id FROM Account.Contacts)        from Account where id = '0011a000004eVlYAAU'    How do I access the "id" from "Account.Contacts".  I found an answer but I am not able to make it work.  For(string b : [Select Name, id, (SELECT id FROM Account.Contacts)        from Account where id = '0011a000004eVlYAAU'])         {              system.debug(b.Account.Contacts);         }


I was wondering what the best way is to write ≙ in LaTex? I have used   \hat{=}    and   \widehat{=}   but somehow am not very satisfied with the looks. Is there an alternative ?   Thank you!


Automatically run code on referenced assembly during startup?? What is this called?

In .NET, there is something that can automatically run a piece of code in a referenced assembly when the assembly is loaded.   For example, you can have a class decorated with a sort of attribute that lives in project Foo(A Class Library). And project Bar(A Web App) simply references project Foo. When Bar loads, that decorated code in Foo gets run somehow. I believe this is a newer feature.  Can someone tell what this feature is called??  Update: Thanks Shiva! Not Module Initialize. Although it lead me to the right answer.  Thanks all!!


How does one evaluate $\sum_{t=1}^\infty tr^t$?

WolframAlpha says that $\sum_{t=1}^\infty tr^t=\frac{r}{(r-1)^2}$, which seems reasonable. But how can one derive this by hand?   Also, is there a name for this series?


When we spin a coin on a table, we observe 2 things:   It slows down and stops after sometime. It does not stay at just one point on the table but its point of contact with table changes with time.   I was trying to explain quantitatively this but I am stuck at how to take frictional torques into account. Any help will be appreciated.


What is the difference between Shrink Database and File?

DBCC ShrinkDatabase() DBCC ShrinkFile()    Do I need to run both DBCC commands in order to shrink the database? What is the difference between these two above?


We don't know when a nucleus will decay. Then how can find its half life?

I mean how can we say that in 5730 years, 1/2 the no. of C14 nucleus will decay because in reality we don't know when a particular nucleus will decay


sudo apt-get install nfs-kernel-server I have my /etc/expots file here;  /mnt/extHD 192.168.1.0/24(rw,sync,no_subtree_check,no_root_squash)  I have restarted all the services and set ufw to allow nfs, yet when I do a  sudo showmount -e localhost  I get;  clnt_create: RPC: program not registered


Summations of Legendre Symbols with an odd prime p

Let $p$ be an odd prime. For any integer $k$, define $S(k,p) = \sum^{p}_{x=1}(\frac{x(x+k)}{p})$.   (i) Show that S(0,$p$) = $p$-1  (ii) Show that if p does not divide k then $S(k,p) = S(1,p)$  (iii) Conclude that if p does not divide k then $S(k,p) = -1$  Been struggling with this question for a couple of days with no progress.


How can I upload a file when I ask a question?

I haven't found anyway to upload a text file when I am asking a question. How can I do so?


I'm using C# on Framework 3.5.  I'm looking to quickly sort a Generic List<T>.  For the sake of this example, let's say I have a List of a Person type with a property of lastname.  How would I sort this List using a lambda expression?  List<Person> people = PopulateList(); people.OrderBy(???? => ?????)


Was this word used under the influence of the Ring?

It seems that everyone who dealt with the One Ring called it "precious". Did the Ring force people to use that moniker? Or was it some artefact of Middle-Earth languages as designed by Tolkien? Or merely the fact that the whole books was a re-telling by Bilbo in The Red Book of Westmarch, and thus he was solely responsible for the word choice?  First, we see Gollum/Sméagol:  'The murder of Déagol haunted Gollum, and he had made up a defence, repeating it to his "precious" over and over again, as he gnawed bones in the dark, until he almost believed it. It was his birthday. Déagol ought to have given the ring to him. It had previously turned up just so as to be a present. It was his birthday present, and so on, and on. 'I saw him there,' answered Gandalf, 'but before that he had wandered far, following Bilbo's trail. It was difficult to learn anything from him for certain, for his talk was constantly interrupted by curses and threats. "What had it got in its pocketses?" he said. "It wouldn't say, no precious. Little cheat. Not a fair question. It cheated first, it did. It broke the rules. We ought to have squeezed it, yes precious. And we will, precious!"  ... and countless other instances in The Hobbit and LOTR.   OK, that may be just Gollum's pet name for The One Ring, or pecularity of wording... except we also have...  Bilbo:  'If I am it is your fault,' said Bilbo. 'It is mine, I tell you. My own. My precious. Yes, my precious.' 'Well, if you want my ring yourself, say so!' cried Bilbo. 'But you won't get it. I won't give my precious away, I tell you.' His hand strayed to the hilt of his small sword.    OK, fine, we can write Bilbo's usage of the word on the fact that he heard Gollum use it in the cave when he found the RIng and subconsciously imprinted the word. BUT then we have ...  Frodo:  'Why, why wasn't it destroyed?' cried Frodo. 'And how did the Enemy ever come to lose it, if he was so strong, and it was so precious to him?' He clutched the Ring in his hand, as if he saw already dark fingers stretching out to seize it. 'What do you mean?' said Frodo. 'Surely the Ring was his precious and the only thing he cared for? But if he hated it, why didn't he get rid of it, or go away and leave it?' Frodo drew the Ring out of his pocket again and looked at it. It now appeared plain and smooth, without mark or device that he could see. The gold looked very fair and pure, and Frodo thought how rich and beautiful was its colour, how perfect was its roundness. It was an admirable thing and altogether precious.  Now, we don't even have the "he heard it" excuse - he didn't discuss the Ring with Bilbo at any time previous! The third quote can be exlained by the fact that her - by then - heard Gandalf use the word when discussing Gollum... BUT the first two quotes definitely happened before he heard that word from Gandalf.   Not only that, but we have other characters use the word as well:  Tom Bombadil:  'Show me the precious Ring!' he said suddenly in the midst of the story: and Frodo, to his own astonishment, drew out the chain from his pocket, and unfastening the Ring handed it at once to Tom.   ... and Isildur, as related in his scroll (recited by Gandalf)  But for my part I will risk no hurt to this thing: of all the works of Sauron the only fair. It is precious to me, though I buy it with great pain.   ... and while at it, let's throw in an Istari (Saruman):  'He came and laid his long hand on my arm. "And why not, Gandalf?" he whispered. "Why not? The Ruling Ring? If we could command that, then the Power would pass to us. That is in truth why I brought you here. For I have many eyes in my service, and I believe that you know where this precious thing now lies.'


Sufficient condition on integrator that Riemann-Stieltjes integrable function on $[0,1]$ is Lebesgue integrable.

Let $\alpha$ be nondecreasing on $[0,1]$. Then Riemann-Stieltjes integrable function is well defined with respect to the integrator $\alpha$. I was wondering if the following assertion is true:  (1) If $f$ is Riemann-Stieltjes integrable on $[0,1],$ then $f$ is Lebesgue integrable on $[0,1]$ with respect to the measure induced by $\alpha$. (2) Do we need additional hypotheses on $\alpha$ for guaranteeing the above assertion? For example, $\alpha$ is right-continuous.  I would be grateful if you give any comment for my question.


What are some good math specific study habits?

What are/ were some of your good mathematician's study habits that you found really worked for you?  I'm a CS major at a respected school and have a solid GPA...  However, I definitely lack when it comes to getting great grades in relatively higher level maths (300 and 400 level).  I feel that even though I study a lot, I perhaps don't study effectively enough.  I would like to ask for any tips/ tricks as to how you keep yourself focused, motivated etc that could perhaps help me or others.  Thanks in advance.


Gaming with Virtualbox, has it worked for you?

Currently I am using Windows 8. I have a virtual box with Ubuntu set up for development. Aside from that I sometimes just want to relax and enjoy a game (Battlefield 3, Skyrim, Saints Row: The Third, etc) after hours of research and development.   I want to have my main machine with linux, and install windows on a virtual box.   What I want to know, from those who have tried or seen it:   How is the performance? I've never been clear on this but, even if I install the correct drivers on the windows box, will it matter? At least on this part, I'm just curious how it offload. Which drivers will matter the most.  Mouse and Keyboard integration, I'll be honest, sometimes the mouse integration in Virtual Box is a bit frustrating, mouse cursor disappears, etc.    I'm not sure if this is the right place to ask. I'm merely trying to come back to linux, yet I'm a PC gamer so I can't throw away Steam. I'm aware of the linux client, but most of those games won't work.   If there's a right place to ask this whether StackExchange sites or any other site let me know.   Cheers and I hope those in the same position find a middle ground.


Command from batch file not recognized unless run from Desktop OR as administrator

I have installed  so I can extract files by running batch files, I added the bin folder to both PATH (user variables) and Path (system variables), but I still have the following problem:  I created this batch file and saved it as a .cmd file:  unzip timeout /t 10 /nobreak   If I place the file in any folder on my computer and double click it, I get this message:  'unzip' is not recognized as an internal or external command, operable program or batch file   If I right-click it and choose Run as administrator, then the batch file is run and unzip is recognized.  Then, it happened that I moved the same file on the Desktop, double click and it worked. I tried moving the file around in different locations, but I still can't get it working. So I have to either keep it on desktop or run it as administrator.  I am running Windows 8.1.  How can I make it run normally (non-administrator) without having to keep it on the desktop?  Output from echo %path% in a cmd shell:  C:\bin\emsdk;C:\bin\emsdk\mingw\4.6.2_32bit;C:\bin\emsdk\clang\e1.34.1_64bit;C:\bin\emsdk\node\0.12.2_64bit;C:\bin\emsdk\python\2.7.5.3_64bit;C:\bin\emsdk\emscripten\1.34.1;C:\ProgramData\Oracle\Java\javapath;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Windows\CCM;C:\bin\git\bin\;C:\bin\Git\cmd;C:\Program Files (x86)\Brackets\command;C:\WINDOWS\System32\WindowsPowerShell\v1.0;C:\Users\I323547\AppData\Local\Programs\Python\Python35-32\Scripts\;C:\Users\I323547\AppData\Local\Programs\Python\Python35-32\;C:\Users\I323547\AppData\Roaming\npm;C:\program files\apache-maven-3.3.9\bin;C:\Users\I323547\AppData\Local\atom\bin;C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\;C:\WINDOWS\System32\WindowsPowerShell\v1.0;C:\WINDOWS\System32\WindowsPowerShell\v1.0;C:\Program Files\nodejs\;C:\Program Files (x86)\GnuWin32\bin;C:\Users\I323547\AppData\Local\Programs\Python\Python35-32\Scripts\;C:\Users\I323547\AppData\Local\Programs\Python\Python35-32\;C:\program files\apache-maven-3.3.9\bin;C:\bin;C:\Users\I323547\AppData\Roaming\npm;C:\Program Files (x86)\GnuWin32\bin;    The unzip.exe live in this folder which path knows about:  C:\Program Files (x86)\GnuWin32\bin;


Let $r$ be a root of the polynomial $p(x)=(\sqrt{3}-\sqrt{2})x^3 + \sqrt{2}x-\sqrt{3}+1$. Find another polynomial $q(x)$, with all integer coefficients, such that $q(r)=0$.


I've been trying to solve these questions for the past few hours with no luck:   If $G$ is an infinite abelian group all of whose proper subgroups are finite, then $G$ is a  Prüfer $p$-group for some prime number $p$. If $G$ is a group such that $G \equiv G/H$ for all proper normal subgroup $H$ of $G$, then $G$ is a  Prüfer $p$-group for some prime number $p$.   Any elementary idea for these questions (by using only the Chapter I of Hungerford's book). Thanks in advance.


Local variables in zsh functions and their return code

Consider the following zsh function function foobar() {     local foo=$(fzf) && echo "$foo-bar" }  if instead of selecting one of the results of the fzf command I exit fzf without selecting anything, the second command is executed anyway and I get -bar  on stdout. If instead I assign the variable without the local attribute the second command is only executed if I select something from fzf, which is what I want. Since assigning variables with the local attribute in functions is preferable to not doing that, how can I fix that behaviour?


I tried to make this scene from blender guro tutorial, but i got problem in my lamp which is to noisy. Is there a solution without increasing my samples render?  Im beginner for this stuff.


How do I permanently assign an IP address with DHCP?

I am wondering if there is anything (software or hardware) out there that can do something I think I may have made up, Dynamic Static IPs. The idea is that when a new device connects to the local network this device/software acts as a DHCP server, if the device is new then it dynamically assigns it a new address that has never been used before and stores this MAC Address IP Address combination in a database, if the device's MAC is in the database the devices gets the same IP as before.  I am aware this is similar to sticky IP allocation but I don't want the IPs to stick for a while I want them to be superglued on for ever.  Bonus question: Is this possible using a Raspberry Pi running Raspbian on a network with around 100 devices? The RPi is already acting as the DHCP server and the router has this capability but it is turned off.  Many thanks in advance for any and all help offered!


A question about proving that there is no greatest common divisor

I have to answer this question:  Prove that in the ring $\mathbb Z[\sqrt{-5}]$ there's no gcd to $6$ and $2\cdot (1+\sqrt{-5})$.  I have no clue how to do this but however I've tried to prove that their sum $$6+2\cdot (1+\sqrt{-5}) = 8+2\cdot\sqrt{-5}$$ is not in $\mathbb Z[\sqrt{-5}]$ but I was not able to do this.  How should I proceed?


Replacing variables in files with value from another file

I have an input file which contains variable and their values.  $ cat input.txt var1=SomethingNew var2=SecondPrhase classpath=/this/is/some/path   I have another directory in which there are multiple files across many sub-directories with these variables. I want to replace all these variables in all files with values from above "input.txt" file. Thanks in advance.


How can I view posts made with "Facebook Comment Sections" on other websites?

I'm seeing blogs as well as a few start-up projects using Facebook Walls as their comments sections. These are integrated with your Facebook account and generates a Facebook Notification when you receive responses to your comments. Clicking the notification takes you to the original website.  Since each of these websites has a separate "Wall" for different content, it is difficult to find your posts if you don't remember where you made the original post.  Is there a way to find posts that you've made to external Facebook Walls on third-party websites?


Recently i had added a 2GB DDR3 ram in my acer laptop. As a result my total ram is 4GB (2x2). I was running ubuntu 12.04 32bit(pae kernel). Everything was working fine. Now i have upgraded (new install) to 13.04 64bit. Suddenly i noticed that system is showing only 1.7GB. So i run lshw to ensure the fact. But lshw shows correct result (4GB = 2x2). How could i solve this??? There is no settings in BIOS for ram at all. My system is newly installed. No additional applications is installed except amd-catalyst driver.  System:  Acer aspire 4250 E-450 apu       Note: BISO also showing that 4GB ram installed.


Bash function with `getopts` only works the first time it's run

I defined the function f in Bash based on  (under "An option with an argument"):  f () {   while getopts ":a:" opt; do     case $opt in       a)         echo "-a was triggered, Parameter: $OPTARG" >&2         ;;       \?)         echo "Invalid option: -$OPTARG" >&2         return 1         ;;       :)         echo "Option -$OPTARG requires an argument." >&2         return 1         ;;     esac   done }   Whereas they use a script, I directly define the function in the shell.  When I first launch Bash and define the function, everything works: f -a 123 prints -a was triggered, Parameter: 123. But when I run the exact same line a second time, nothing is printed.  What's causing this behavior? It happens in Bash 3.2 and 4.3, but it works fine in Zsh 5.1. This is surprising because the example was supposed to be for Bash, not for Zsh.


I'm learning how to use unittest in python. I have a class that receives a pandas dataframe in it's init method. class GenericClass:      def __init__(self, data):                  if not (isinstance(data, pd.DataFrame) or isinstance(data, pd.Series)):             raise ValueError(f'The object {data} must be a pd.DataFrame or a pd.Series')                  self.data = data  I've created a file called test.py. And in this file i'll test the methods of GenericClass. import unittest from file import GenericClass  class TestHistan(unittest.TestCase):      def test_input(self):         # no idea on how to implement this  My question is, how do i make a test function that tests the inputs passed on the init method of the generic Class?


A chest of drawers has 3 drawers. Each drawer has 2 boxes. The boxes of one drawer contain a silver coin in each respectively, the boxes of another a gold coin in each box, and the boxes of the third drawer a gold and a silver coin, respectively. A drawer is selected at random and a box from the drawer is selected at random and opened. The coin is found to be silver. What is the probability that the coin in the other box is gold?  I got 0.5.


Each open interval is a countable union of closed sets.

How can we prove this $$(a, b)= \cup_{n=1}^\infty [a + 1/n, b - 1/n],$$ ?  First: it is clear that $\left [ a + \frac{1}{n}, b - \frac{1}{n}\right ] \subseteq (a, b)$ for every n, then $\cup_{n=1}^\infty [a + 1/n, b - 1/n] \subseteq (a, b) $. what about the other inclusion?


Is it good practice to use the least amount of IDs in an HTML Page?

We are discussing the pros and cons of using id attributes versus class attributes in our website's HTML tags. I use IDs rather liberally. This includes the use of nested IDs such as:

  ....

   In this case, MediaSection is a part of the page unique to this HTML file (referenced by the body tag with thisPage id). When I write CSS to style the mediaImages section it would look like this:  #thisPage #mediaSection #mediaImages {     vertical-align: bottom; }   I write the CSS rules like this for legibility purposes even though I know we just need #mediaImages. My co-worker says that this is bad practice: IDs are more expensive and could compromise browser performance because they give the web browser more information to keep track of. His recommendation is to use classes instead. For example, rewriting the above example:

  ....

   Is there merit to using classes instead of ids for this situation?


How can I find the location of an icon of a launcher in use?

I have a launcher on my desktop and want to add another one manually with the same icon.   When I go to the preferences of the existing launcher and click the icon, it doesn't take me to the folder where the icon is stored but just to my home folder.  How can I find out where the used icon of the launcher is located in my system?


Force Publish Future (Scheduled) Posts Immediately

I am trying to force publish 'future' or 'scheduled' posts, and I am having trouble  The reason I am asking is because I am creating a site that allows users to do the editing on the front of the site, so I need a button that will allow users to force publish scheduled posts.   Right now I am just trying to find a process or idea that works consistently, and all I have come up with is this:  1) Adjust the scheduled time to the past  2) Changing post status from future to draft 3) Change draft back to scheduled 4) Server realizes the scheduled post time has past and marks it published  Needless to say this isn't ideal. For other status changes I was able to use the status button seen here:  .  I am at a loss on this one because I can't even get the process working on the backend I have looked around a great deal and see that others have had similar problems (e.g. ) but cannot find a solution.  Asking the community for any ideas?


This is a question from an old prelim in complex analysis. Show that if $f$ is an analytic function such that $|f(z)| \leq \frac{1}{1-|z|}$ for $|z|<1$, then $|f'(0)| \leq 4$. I tried using both Cauchy's $ML$-Estimates along with the Cauchy Integral Formula and even the Schwarz-Pick Lemma, but I still do not get the desired result. Any suggestions as to how best to proceed?


How long could we expect Eldarion to live?

Elrond (who was 50% Elven) lived well over 6,000 years before departing Middle-earth. Because of his distant Elven lineage Aragorn lived over 200 years before he died. As a 3/4 Elf Arwen was immortal and lived for 2901 years before dying of grief (after the death of Aragon). Their son Eldarion would have been at least 37.5% elven. Should he expect his lifespan to be somewhere between Arwen's and Aragorn's? Or does he have enough Elven blood to live forever?


How to remove all the files in a directory?

I am trying to remove all files and subdirectories in a directory. I used rm -r to remove all files, but I want to remove all files and subdirectories, excluding the top directory itself.  For example, I have a top directory like images. It contains the files header.png, footer.png and a subdirectory.  Now I want to delete header.png, footer.png and the subdirectory, but not images.  How can I do this in linux?


How do I test a private function or a class that has private methods, fields or inner classes?

How do I unit test (using xUnit) a class that has internal private methods, fields or nested classes? Or a function that is made private by having  (static in C/C++) or is in a private () namespace?  It seems bad to change the access modifier for a method or function just to be able to run a test.