Schengen visa for Spain and France
Should my first trip be to the country which issued my Schengen Visa?
The hydrogen protons undergo quantum tunnelling in the the sun to fuse into helium, but are only able to do so as they are under immense heat and pressure and the protons and electrons get separated. But our digestive system also makes use of quantum tunnelling to quicken the digestive process, but how do the enzymes free up the electrons when our body temperature is so low? Shortest path from points in one layer to points in another layer via roads in QGIS Add markdown toolbar to mobile web On the full site, there's that helpful Markdown toolbar above the post box:   This is conspicuously missing in the mobile site:   It's difficult just to get a bracket on my iPad. Backticks aren't even available. If there's a view that really needs it, i vote mobile. I have the below list of files  aro_tty-mIF-45875564pmo_opt aro_tty-mIF-45875664pmo_opt aro_tty-mIF-45875964pmo_opt aro_tty-mIF-45875514pmo_opt aro_tty-mIF-45875524pmo_opt   that I need to rename to  aro_tty-mImpFRA-45875564pmo_opt aro_tty-mImpFRA-45875664pmo_opt aro_tty-mImpFRA-45875964pmo_opt aro_tty-mImpFRA-45875514pmo_opt aro_tty-mImpFRA-45875524pmo_opt Helix in a helix I am trying to work out a "helix in a helix" mathematically.  Intuitively I think of this as a steel cable, which is made up of a number of smaller steel cables all bound together in spiral.  If I wanted to find the length of one of the individual cables, it would be bound in a spiral in the smaller cable and then those cables bound in a larger spiral cable.  I know that if I wanted to do a helix whose ends meet, I would use the parametrization $$((a+b\cos(\omega{t}))\cos{t},(a+b\cos(\omega{t})\sin{t},b\sin(\omega{t})),t=0..2\pi$$ I've been trying to map out in my head how to, instead of curling the helix, making the helix travel in the path of a helix.  I've achieved it partially with $$((a+b\cos(\omega{t}))\cos{t},(a+b\cos(\omega{t})\sin{t},t),t=0..\infty$$ But this doesn't keep the smaller helix in tact, and turns it into a sine wave helix.  I've also tried  $$((a+b\cos(\omega{t}))\cos{t},(a+b\cos(\omega{t})\sin{t},tb\sin(\omega{t})),t=0..2\pi$$ But this gives me sort of a nautilus shape where the helix curls into itself and increases in size and curls around into itself.  What am I missing?  EDIT:  Also, what if we wanted to do this again, like a 'helix in a helix in a ... in a helix'? Publishing a review in a peer-reviewed Wiki vs a traditional journal? The topic of Wikipedia contribution has come up before, but I am interested in the community's opinion on peer-reviewed wiki publishing (e.g., Scholarpedia). I would like to know if there is any advantage for a PhD student to publish in such an online venue versus the traditional journal publication for review content. The advantages I see to the wiki approach is free of charge publication, open access for all, not necessarily being limited by character limits. However, the disadvantages I see could be the citation being completely ignored by the intended audience and therefore missing out on the benefits of scientific communication and the possible loss of accompanying reputation for the publication. I would also worry these publications would be ignored or minimized by future supervisors and review committees. There are a lot of software in Windows to merge PDF files but how can we do the same in Ubuntu? Taking advantage of one-time pad key reuse? Suppose Alice wants to send encryptions (under a one-time pad) of $m_1$ and $m_2$ to Bob over a public channel.  Alice and Bob have a shared key $k$; however, both messages are the same length as the key $k$.  Since Alice is extraordinary lazy (and doesn't know about stream ciphers), she decides to just reuse the key.  Alice sends ciphertexts $c_1 = m_1 \oplus k$ and $c_2 = m_2 \oplus k$ to Bob through a public channel.  Unfortunately, Eve intercepts both of these ciphertexts and calculates $c_1 \oplus c_2 = m_1 \oplus m_2$.     What can Eve do with $m_1 \oplus m_2$?     Intuitively, it makes sense that Alice and Bob would not want $m_1 \oplus m_2$ to fall into Eve's hands, but how exactly should Eve continue with her attack? Does there exist an $a_0$ such that the sequence $a_{n+1} = 2a_n + 1$ is prime for all $n \ge 0$? Daily review limit exceeded I have just reached my limit of suggested edits for the day when I noticed someone else has 21, when the limit is 20, how can this be? How can I rank observations in-group faster? Sort on a string that may contain a number I need to write a Java Comparator class that compares Strings, however with one twist.  If the two strings it is comparing are the same at the beginning and end of the string are the same, and the middle part that differs is an integer, then compare based on the numeric values of those integers.  For example, I want the following strings to end up in order they're shown:   aaa bbb 3 ccc bbb 12 ccc ccc 11 ddd eee 3 ddd jpeg2000 eee eee 12 ddd jpeg2000 eee   As you can see, there might be other integers in the string, so I can't just use regular expressions to break out any integer.  I'm thinking of just walking the strings from the beginning until I find a bit that doesn't match, then walking in from the end until I find a bit that doesn't match, and then comparing the bit in the middle to the regular expression "[0-9]+", and if it compares, then doing a numeric comparison, otherwise doing a lexical comparison.  Is there a better way?  Update I don't think I can guarantee that the other numbers in the string, the ones that may match, don't have spaces around them, or that the ones that differ do have spaces. Get content from a url using php I have a cable as in the drawing. The black parts are insulators and the brown parts are copper, so there is a big copper cable and inside are two smaller copper cables. When the big copper cable is tied to ground I can use a time domain reflectometer (TDR) on the smaller cables to determine the length of the cable. What happens if the big copper cable is in use with a current running through it that is 1000 times bigger than the current running through the two smaller copper cables? Will I still be able to determine the length with a TDR? I think there shouldn't be a capacitance between the two smaller copper cables - but how am I then able to measure with it a TDR? Does $\lim_{n\to\infty}\underset{n}{\underbrace{\cos(\cos(...\cos x))}}$ exist? Possible Duplicate:         Does the following limit exist?  $$\lim_{n\to\infty}\underset{n}{\underbrace{\cos(\cos(...\cos x))}}$$  If yes, find the limit.  If no, please explain why the limit doesn't exist.  I think, the limit exists.  So, I tried to use Squeeze theorem but didn't work. When reviewing flags, either from the queue or from the flagged post, I often want to know what the flagger could have done in addition to, or instead of, flagging for mod attention.  Does he have the rep to downvote?  To comment?  To vote to delete?  Knowing this doesn't necessarily affect how I handle the flag, but if there's a possible teaching moment there I use the flag response to point it out.  But I can't find this out unless I click through to the user's profile (unless I already know this user, of course).  Would it be possible to get the flagger's reputation in a tooltip, like what's already done for comments? Blank white desktop icons on new Windows 7 install Non-ASCII characters in external links Minecraft directory doesn't have a 'Resource Packs' folder? I go into my .minecraft folder and there's Assets and all the other files and folders, but no resource packs folder?  If I create one manually, and place the textures inside, they don't show up in-game.  I'm on a Mac. What is the agreed upon definition of a "positive definite matrix"?