I overstayed in the US by about 4 years in 1997 and left voluntarily. Can I now come back as a tourist?
Overstayed my US visa for over 9 years, never got deported, can I return as a tourist?
Why should I register my account? I can use many of the site's features while unregistered. I am looking for a simple explanation of what benefits a user can have from registering.     For more information, see  in the . Explain how (or if) a box full of photons would weigh more due to massless photons I understand that mass-energy equivalence is often misinterpreted as saying that mass can be converted into energy and vice versa.  The reality is that energy is always manifested as mass in some form, but I struggle with some cases:  Understood Nuclear Decay Example  In the case of a simple nuclear reaction, for instance, the total system mass remains the same since the mass deficit (in rest masses) is accounted for in the greater relativistic masses of the products per $E=\Delta m c^2$.  When a neutron decays and you are left with a fast proton and a relativistic electron.  If you could weigh those two without slowing them down, you would find it weighed as much as the original neutron.  Light in a Box  This becomes more difficult for me when moving to massless particles like photons.  Photons can transmit energy from one heavy particle to another.  When a photon is absorbed the relativistic mass (not the rest mass) of the (previously stationary) particle that absorbs it increases.  But if my understanding is correct, the energy must still be manifested as mass somehow while the photon is in-flight, in spite of the fact that the photon does not have mass.  So let's consider a box with the interior entirely lined with perfect mirrors.  I have the tare weight of the box with no photons in it.  When photons are present the box has an additional quantifiable amount of energy (quantified below) due to the in-flight photons.  Say there are $N$ photons... obviously assume $N$ is large.  $$\Delta m = \frac{ E }{ c^2 } = \frac{ N h }{ \lambda c}$$  Interactions are limited to reflections with the wall, which manifest as a constant pressure on the walls.  If I hold this box in a constant gravitational field (like the surface of Earth) then there will be a gradient in the pressure that pushes down slightly.  Is this correct?  Wouldn't there still technically be mass as the photons are in-flight, which would cause its own gravitational field just as all matter does?  How is this all consistent with the assertion that photons are massless?  Is it really correct to say that photons don't have mass?  It seems to be a big stretch.  Please offer a more complete and physically accurate account of this mirror-box. Insert results of a stored procedure into a temporary table When I ping I have this display:  &gt; ping -i 4 www.google.fr  64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=503 ttl=46 time=45.5 ms ....... ....... 64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=508 ttl=46 time=44.9 ms 64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=509 ttl=46 time=45.1 ms   I'd like to have the time of the ping before.   Something like:  &gt; (right functions) + ping -i 7 www.google.fr  mardi 15 mai 2012, 10:29:06 (UTC+0200) - 64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=503 ttl=46 time=45.5 ms ....... ....... mardi 15 mai 2012, 10:29:13 (UTC+0200) - 64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=508 ttl=46 time=44.9 ms mardi 15 mai 2012, 10:29:20 (UTC+0200) - 64 bytes from wi-in-f94.1e100.net (173.194.67.94): icmp_seq=509 ttl=46 time=45.1 ms   How would you do this in a command line (if it's possible)? What happens when a photon hits a beamsplitter? Yesterday I read that we can affect the path and the 'form' (particle or wave) of a photon after the fact ().  Part of what is puzzling me is the beam-splitter. Are the individual photons actually being split into two new photons of lesser energy?  This  implies that you cannot split a photon but it seems that beam splitters do exactly that. Can I use my Schengen visa for multiple purposes I was issued a Schengen visa for 90 days validity with multiple entry. Initially I planned for tourism to France and Switzerland and accordingly I have written the purpose as tourism only and I will be travelling as well for a week and coming back to India. First I am using for tourism for one week and travelling back to India.  Now, I also need to travel again to Schengen area to the same countries for business purpose for one week again. Can I use the same visa or do I need to get a new one? Aufbau principle in modern quantum theory Viewer-independent copyable spaces at the beginning of a line? abhigenie92@ubuntu:~$ (sleep 2; echo $BASH_SUBSHELL ;sleep 2) 1 abhigenie92@ubuntu:~$ (sleep 2; echo $BASH_SUBSHELL ;sleep 2)&amp; [1] 3297 abhigenie92@ubuntu:~$ 1  [1]+  Done                    ( sleep 2; echo $BASH_SUBSHELL; sleep 2 )   What happens when launch it as a background process, why don't I get the prompt back and I have to press Enter? In both cases it launches a child shell. How does gravity work on Star Wars ships? Inspired by the question , how does gravity work on the Millennium Falcon and other ships its size? The passengers are not strapped in and regularly move around just easily as they would on a planet with Earth's gravity.   The answer for the Death Star refers to gravity often being "coreward" (presumably taking advantage of the natural gravity an object of such substantial mass would have), but that doesn't apply for a small ship. So how is gravity accomplished? Show only hidden files (dot files) in ls alias Is it possible to set the "urgent" flag in Gmail for outgoing mail? I'd like to be able to flag time-sensitive emails as such. How can we prove that a binomial coefficient $n\choose m$is divisible by the ratio of $n$ and $\gcd(n,m)$? If $a_k\geq0$ is a decreasing sequence converging to $0$, do we have $\lim_{n\to\infty}\frac{\sum_{k=1}^n a_k}n = 0$? Let $a_k\geq 0$ be a non-increasing sequence satisfying $\lim_{k\to\infty} a_k = 0$. Is it always true that $$\lim_{n\to\infty} \frac{\sum_{k=1}^n a_k}n=0$$ ?  I tried proving with "brute force" but failed: Let $\varepsilon&gt;0$. Then there exists a $K\in\mathbb N$ such that $a_k\le\varepsilon$ for all $k\geq K$. Let $C=\sum_{k=1}^K a_k$. We have $$\frac{\sum_{k=1}^{\left\lceil\frac C\varepsilon\right\rceil}a_k}{\left\lceil\frac C\varepsilon\right\rceil}=\frac{C}{\left\lceil\frac C\varepsilon\right\rceil}+\sum_{k=K+1}^{\left\lceil\frac C\varepsilon\right\rceil} a_k\le \varepsilon +\varepsilon\cdot\left( \left\lceil\frac C\varepsilon\right\rceil-K\right).$$  However, this is not good, as the right-hand side depends on $C$, which can get large for small $\varepsilon$.   Also, numerical computations for example with $a_k=\frac1{\log\log k}$ seem to confirm the statement though...  (Additionally, note that I didn't use the non-increasing fact, but I am not sure if it is needed.) Taking back turns, and forgotten privileges A generic question across most board games: once a player has taken their turn (taken their finger off the piece they are playing), should they be allowed to change their mind?  Similarly, if a player forgets to take a privilege, such as an occupied building in Puerto Rico giving an extra worker, or plantation, if they remember a few moves later, should they be allowed to take the privilege?  Very few rules explicitly express how these events should be dealt with, so they are generally left up to the group. However, my group's rules will change depending on the personality of the players playing (not all members are available each time we play). I would like to make this consistent, and would appreciate feedback on how others deal with this scenario. How to Remove URLs from Google Search Engine I'd love to see if there are trends over time, patterns of improving behaviour after being flagged, consistent reoffenders, most misused types of flag, etc.  I understand the who-said-what-about-who aspect would most likely cause this to be denied, but even anonymised data would be interesting to dig through. Can I SSH into a specific directory? Roll a 6-sided die until the total $\geq M$. Mean amount by which $M$ is exceeded? Here is the question:  You roll a fair 6-sided dice iteratively until the sum of the dice rolls is greater than or equal to M. What is the mean and standard deviation of the sum minus M when M=300?  Should I write a code to answer these kind of questions?  Please give me some hints on that. thanks! How can I bind the meta key (a.k.a.  / Windows key) to a left click? Hitting the meta key should trigger a left click, and pressing down on it should allow me to drag and drop (just like it would do when holding down left click).  I tried using System Preferences -> Shortcuts and Gestures:    but I cannot set "meta" alone as being a shortcut.  I use Kubuntu 14.10 Plasma 4 and Kubuntu 14.04 LTS x64.   (On Windows 7 SP1 x64 Ultimate I can achieve that using the program .)