Do I need a Transit Visa for layover at London Heathrow Airport? My wife has a Visitor Visa for Canada and daughter has Study Permit for Canada which is valid more than six months from the date they are travelling.  They have a layover at London for 6 hours which does not cross the day meaning day of landing and boarding the next flight is on the same day.  So, do they require a Transit Visa? I have already gone through the  to check the same but I could not understand last question which says ask your airline whether you need to pass the border control.
Is there a way to find out if I need a transit visa for a layover in the UK? Is there a website or some other way to find out if I need a transit visa for a short stop in the UK on my way somewhere else? Ideally this should give me the answer for all nationalities, and take into account any other visas I may have.
What is the recommended wording for a generic error message How to update libavcodec on ubuntu 14.04? On Ubuntu 14.04.5 I just upgraded firefox to version 50.0; now there is a message on some pages which reads:   libavcodec may be vulnerable or is not supported, and should be updated to play videos   So how can I update libavcodec?  A simple   sudo apt-get install libavcodec   gives the following output:  Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package libavcodec   So maybe I don't have libavcodec installed in the first place? So why do I get this message...? Repeating the consonant in many words in a sentence or phrase In the movie 'V for Vendetta' you have for example (bold part):     Evey: Who are you?        V. : Who? Who is but the form following the function of what and what I am is a man in a mask.      Evey: Well I can see that.        V. : Of course you can, I’m not questioning your powers of observation, I’m merely remarking upon the paradox of asking a masked man who he is.      Evey: Oh, right.      V. : But on this most auspicious of nights, permit me then, in lieu of the more commonplace soubriquet, to suggest the character of this dramatis persona.      V. : Voila!   In view humble vaudevillian veteran, cast vicariously as both victim and villain by the vicissitudes of fate. This visage, no mere veneer of vanity, is a vestige of   the “vox populi” now vacant, vanished. However, this valorous visitation of a bygone vexation stands vivified, and has vowed to vanquish these venal and virulent vermin, van guarding vice and vouchsafing the violently vicious and voracious violation of volition. The only verdict is vengeance; a vendetta, held as a votive not in vain, for the value and veracity of such shall one day vindicate the vigilant and the virtuous. Verily this vichyssoise of verbiage veers most verbose, so let me simply add that it’s my very good   honour to meet you and you may call me V.       Evey: Are you like a crazy person?      V. : I’m quite sure they will say so.   What do you call sentences like these? And do you know some other ones? Rainbow Six Siege Insane Load times? Computer or Internet? I have a high-end computer with decent ethernet yet whenever I join a game in Siege everyone finishes loading and it takes me 1-5 minutes. Is this because of my internet or computer?   Specs:  CPU - i7-7700k GPU - GTX 1080 16GG RAM 5900 RPM 4TB Hard drive Every Christmas, Harry receives a mediocre gift from the Dursleys. In Harry Potter and the Chamber of Secrets he gets a toothpick.     At that moment, Hedwig swooped into the room, carrying a very small package in her beak.     “Hello,” said Harry happily as she landed on his bed. “Are you speaking to me again?”     She nibbled his ear in an affectionate sort of way, which was a far better present than the one that    she had brought him, which turned out to be from the Dursleys. They had sent Harry a toothpick    and a note telling him to find out whether he’d be able to stay at Hogwarts for the summer    vacation, too.    They hate owls, but obviously use them to contact Harry at school? Topic models and word co-occurrence methods Comma usage with compound sentences {actually compound predicates as per Rob's answer} Rule 101 of compound sentences is that a coordinate conjunction must be accompanied by a comma most of the time when joining independent clauses, yet I stumble across sentences all that time that seem to abuse this rule. Normally, it's a case of the subject not being present in the second clause, as in the following example:      "They usually start out as an abbreviation, but turn into acronyms   when they become well known."   (taken from the Oxford Style Manual)   To me, this comma cannot be correct because the clause after the comma doesn't contain a subject and therefore cannot be independent (right?). As far as I'm concerned, it's not the 'Comma to set off a contrast rule because I can find plenty of other where 'and' is used and the subject's missing in the second clause.  what's the deal here?   Thanks in Advance for any responses I may receive! Is there a way to see the history of questions protected by me or another user? Having a record of all actions taken on a site, as is provided by the &quot;activity&quot; and &quot;votes&quot; tabs of our profile, comes in handy very often. Perhaps the most common case is being able to find a question I've interacted with in the past, to see if anything has changed about it. This applies to questions a user has protected as much as anything else. Users are theoretically encouraged to unprotect questions when it's no longer necessary, as emphasized , but in practice they often do not. In many cases it's hard to blame them: unless they specifically marked it as a favourite, the site doesn't keep any record of the question to allow them to find it again. We should help users more easily review their own protections in the future.    For personal review, the votes tab is adequate, but there may also be value in displaying this publicly in the activity tab. There may be users with a history of repeatedly protecting questions over-eagerly. It would be useful to be able to review other users' protection histories to see if this is the case. Even if this is not available to regular users, it may be helpful to moderators, unless their user activity views already allow them to filter down to see this. I want to add a comma in the thousands place for a number.     String.Format()? How does a fork bomb work? WARNING DO NOT ATTEMPT TO RUN THIS ON A PRODUCTION MACHINE   In reading the  I generally follow what's going on with the following code:  :(){ :|:&amp; };:   excerpt of description     The following fork bomb was presented as art in 2002;   its exact origin is unknown, but it existed on Usenet prior to 2002.   The bomb is executed by pasting the following 13 characters into a    shell such as  or . It operates by defining   a function called ':', which calls itself twice, once in the   foreground and once in the background.   However the last bit isn't entirely clear to me. I see the function definition:  :(){ ... }   But what else is going on?  Also do other shells such as ksh, csh, and tcsh also suffer the same fate of being able to construct something similar? These 2 questions have clearly wrong answers with upvotes. And they're still getting votes.  The log file one especially could be tried out, it would fail, but someone still voted it up. A downvote and comment has no effect.  Like we have "vote to close", what about a "vote to delete" for answers. I'd suggest a fairly high rep limit. Or badge ownership realting to the question tags (eg SQL Server)   (SF)   (SO)  Could be similar to this meta question: Highly unbalanced test data set and balanced training data in classification I have a training set with about 3000 positive instances and 3000 negative instances. But my test data set is pretty much un-balanced. The positive set only has 50 instances and negative has 1500 instances.This causes the precision very low. Are there any approaches to solve this problem? I use SVM to build classifier. Proving $A+A'B=A+B$ without truth tables How can I prove the Boolean algebraic rule $$A+A'B=A+B$$ without using a truth table?  With the truth table, it is easy to see that the two are equal, but how can I prove it using lesser Boolean identities? I understand that division by zero isn't allowed, but we merely just multiplied $f(x) = 1$ by $\frac{x-1}{x-1}$ to get $f(x) = \frac{x-1}{x-1}$ and $a\cdot 1 = 1\cdot a = a$ so they're the same function but with different domain how is this possible?  Or in other words why don't we simplify $f(x) = \frac{x-1}{x-1}$ to $f(x) = 1$ before plotting the points. Is it just defined this way or is there a particular reason ?  Note: my book says the domain of $f(x) = 1$ is $\mathbb{R}$ and the domain of  $f(x) = \frac{x-1}{x-1}$ is $\mathbb{R}$ except $1$. In which countries are the visitor's first name and last name compulsory? My name consists of just a first name and no surname.  Will there be a problem regarding my name in the country I visit with a tourist or employment visa? Are there countries in the world where this might be a problem? How can I heal undead creatures? Fifth edition seems to have removed any means of healing undead.  The positive/negative energy duality of 3rd edition seems to be gone. Negative energy spells now do necrotic damage; some undead are resistant or immune to necrotic damage, but it isn't listed as healing them. Classic negative energy spells like inflict wounds and harm don't list undead healing as a possible effect.  For zombies and skeletons it might not matter, but liches and vampires would never risk their necks if they didn't have some way to recover hit points. What is it? I am stuck in a question for Algebraic Structures:  I need to prove: If given any ring $R$, for any $a$ in $R$ $a\cdot a=0$ then $a+a=0$.  (of course $+$, $*$ and $0$ regarding $R$)  I didn't find any question regarding this question. Do we have name for these kind of "flat graphics" images? 3 prong to 4 prong dryer cord change My 2 year old whirlpool dryer has a 3 prong cord. My new house has a 4 prong. The dryer doesn't have a spot for 4 wires. The ground wire coming from the dryer is attached to the dryer itself. A new 4 pronged dryer cord has white, red, black, and green wires. Maybe the green wire hooks to the ground screw with the one coming from the dryer? I was reading an example about describing homomorphisms and I'm having a bit of trouble with this one.  Show there is no group homomorphism $f : \mathbb{Z}_{10} \to \mathbb{Z}_{25}$ such that $f(1) = 3$. The first step of the proof is  $|1| = 10$ in $\mathbb{Z}_{10}$, so $|f(1)| \in\{ 1, 2, 5, 10\}$.  Does this mean that $|f(1)|$ can be $1$, $2$, $5$ or $10$? I see that $|1| = 10$ since $1$ is a generator of $\mathbb{Z}_{10}$, and that $|f(1)|$ seems to be a factor of $10$. If $f(1)$ is the image of $1$ under $f$, how would I find the order of $f(1)$?  Thanks for your help.