I am planning a trip to the US next year and will be travelling around. My idea was to spend a total of six months in the country. I appreciate that under the VWP I will have 90 days initially.
I am currently visiting the USA from the UK (I am a UK citizen) and am intending on staying here for the full 90 days under the Visa Waiver Program.     How long would I have to stay out of the US at the end of this period before returning again?    Would I have to return to the UK, or could I stay with friends in another country (such as Canada) for a while?
Why aren't these loops homotopic? Let $S^1 = \{z \in \mathbb{C} : |z| = 1\}$.  Take the loops $f,g : [0,1] \rightarrow S^1$, $f(t) = 1$, $g(t) = e^{2\pi it}$.  I know these represent different elements in $\pi_1(S^1, 1)$, but I don't see why $F(t,s) = e^{2\pi its}$ isn't a homotopy between $f$ and $g$. Where is the .Trash folder? After upgrade of any app - apps move back from SD Card to phone memory.  After that, to save phone memory, I have to move upgraded app back to SD card.   Is any possibility to avoid this because it is very annoying?  I have Android 5.0.2 on Motorola E second gen phone. arbitrary large finite sums of an uncountable set. I have recently registered some domains on the basically brand new .directory gTLD. Because of operating costs to maintain a gTLD, it is assumed that many of the hundreds being rolled out this year and next will fail. I will admit I am not very knowledgeable on how the TLD process works.   What exactly does a new TLD failing mean? I realize that they lose ICANN accreditation, but does that just mean that they will be no longer be sold? If the .directory TLD were to go under, would my .directory domains be affected? I bought it from domain registrar Gandi if that helps. What is serial voting and how does it affect me? I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause.  During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voting corrected".     What does this mean, and what caused it?  Did I do something wrong? Why did I lose all of that reputation? Is the system punishing me for leaving too many good answers?  Is there any way to earn it back? Hide some fields in the NewForm.aspx for a custom list I have 5 columns in the custom list. Out of which only 3 have to displayed in the NewForm.aspx page.  All of the 5 columns have to be displayed on the EditForm.aspx page. While googling, I have come across the following  :  When I implemented the code that was given on this page, I get an error which says that parentNode is not found. Please guide me how can I implement this requirement.  Any other alternatives other than this are also appreciated. How to list all files ordered by size I would like to list all files in the order of big to small in size and the files could be present anywhere in a certain folder. I am trying to create a map in both Leaflet and OpenLayers 3 which displays the  layer EMAP8 from the WMS http://wms.nlsc.gov.tw/wms. I can't get it to work. I can open the layer in QGIS, but when I try to use it in Leaflet like this:  var overlay_taiwanemapen0 = L.tileLayer.wms('http://wms.nlsc.gov.tw/wms', {     layers: 'EMAP8',     format: 'image/png',     transparent: true,     continuousWorld : true, });   or in OpenLayers 3 like this:  var lyr_taiwanemapen = new ol.layer.Tile({     source: new ol.source.TileWMS(({         url: "http://wms.nlsc.gov.tw/wms",         params: {"LAYERS": "EMAP8", "TILED": "true"},     })),     title: "taiwane-map(en)", });   I get nothing displayed. I can see layers being requested, and data being transferred, but nothing on the map.  What am I doing wrong? Let $(a_n)_{n \in \mathbb{N}}$ be a convergent sequence with limit $a \in \mathbb{R}$. Show that the arithmetic mean given by: $$s_n:= \frac{1}{n}\sum_{i=1}^n a_i \tag{A.M.} $$ also converges to $a$.  I have read:  but unfortunately the answers there don't help me much because I don't understand their substitutions and most of it all, why their substitutions seem to work.   What I know from the problem is that since $a_n$ is convergent and $\epsilon &gt;0$ is given, I can say that:   $$\exists N_1 \in \mathbb{N}, \forall n \geq N_1: |a_n-a|&lt;\epsilon_1 $$ I also know that since $a_n$ is convergent, it is bound, so $(a_n) &lt; M, \ \forall n \in \mathbb{N}$   I need to show that: $$\exists N_2 \in \mathbb{N}, \forall n \geq N_2: |s_n-a|&lt; \epsilon_2$$ I started as follows: $$ \left|s_n-a \right| = \left|\frac{1}{n}\sum_{i=1}^na_i -a\right|= \left|\frac{1}{n}\sum_{i=1}^m(a_i-a)+\frac{1}{n}\sum_{i=m+1}^n(a_i-a) \right| \\ \leq \frac{1}{n} \sum_{i=1}^m|(a_i-a)|+\frac{1}{n}\sum_{i=m+1}^n|a_i-a|$$ I believe to understand that the left sum after the $\leq$ is finite, bound and doesn't depend on the values that $n$ takes on. However, I don't understand where all the substitutions come from and make this proof so seemingly easy to complete.   Is there a general idea I can follow to complete such proofs? Because I know that the last step is to show that the given sum is smaller than $\epsilon$. I also know that I should bring the condition $a_n &lt; M$ into place somewhere, but I don't know where.  If I choose an $n \geq N: |a_n-a|&lt; \epsilon'$ what does that tell me about $|a_i-a|$? I know that they are seemingly the same just with a different index. Show that $8 \mid (a^2-b^2)$ for $a$ and $b$ both odd As the output of df -h shows here, something is eating up 5GB of free space. So, it's not available to use.   I'm also noticing sometimes that the hard disk gets filled up to 100% sometimes. So, I had to restart the machine or delete some unncessary files. Only noticed these in /home partition. Don't know whether these two are related, but appreciate if anyone can put some insight into this.  $ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/sda8             100G   92G  2.7G  98% /home I am interested in publishing a GML file as a WFS. I don't want to use a database like PostgreSQL. What would be the rough steps I need to do for that? I like to use open source software (geoserver). I don't have much experience. I am just looking for a rough guide what kind of software I should look into and which step follows which step.. Why are so many different types of objects white, yet appear gray when they are wet? There are many things with different textures that appear white – salt, beer foam, paper, shaving cream, snow, talcum powder, white paint, etc. The most common answer is all of the frequencies must be reflected in order for us to perceive white, which I already know. There must be more underlining details why such a huge variety of things are white. Furthermore, if you wet paper, snow or talcum powder, they appear off-white or gray. Why is this? EncFs insecure, what to use now I love encfs as it provides file-based encrypting which is quite useful when it comes to cloud storage. But it looks like that especially for this use case, . I'm aware that  but how to deal with it in the meantime? Are there any alternatives that integrate well in ubuntu?  Edit: The security issue I mostly refer to is . It is still present in version 1.8 and makes your files vulnerable if someone get's multiple versions of your encrypted files. If one is worried about services like Dropbox are not that thrustworthy and encrypts folders uploaded into the cloud because of that, the opportunity that the attacker (the service) gets more than one copy of the cyphertext is absolutely given. Use /testfor to make a custom command Basically, I'm trying to recreate the Faction plugins /f map in my single-player without mods as my PC doesn't run them very well. (I know it sounds strange.) I am trying to use the /testfor to test if I have written '/f map' in chat, and if I have, it would show me a custom generated map. I don't know how to word this better xD Essentially what I want is for it to test if I have written a command in chat, and if I have, display something. How to resize partitions? I am rebuilding an old server.  Only one of the five old sites need to go live and all five of the old sites point to the same IP address.  Unfortunately any time a request is made for one of the old sites via their own unique domain names they are passed the pages from the one site that I'm trying to make live.  I would just like the old sites to display a 404 instead of the one site that I'm actually trying to make live.  As an example:   Site 1 (192.168.0.1) [www.first.com] Site 2 (192.168.0.1) [www.second.com] Site 3 (192.168.0.1) [www.third.com]   I want to move site 1 live again.  So I turned on apache on the machine with the IP address of 192.168.0.1, with all of site 1's files in the /var/www directory.  When I browse to 192.168.0.1 or www.first.com I correctly see site 1. When I browse to www.second.com and www.third.com I also receive site 1 which is the problem.  Is there a way I can 404 any request which comes in without www.first.com?  Here is my sites-available:  NameVirtualHost *:80  LogFormat "%h %l %u %t \"%r\" %&gt;s %b" common  &lt;Files ~ "^\.ht"&gt;     Order allow,deny     Deny from all     Satisfy All &lt;/Files&gt;  &lt;Directory /&gt;   Order Deny,Allow   Deny from all   Options None   AllowOverride None   Options None &lt;/Directory&gt;  &lt;Directory /var/www&gt;   Order Allow,Deny   Allow from all &lt;/Directory&gt;  &lt;VirtualHost *:80&gt;         ServerName first.com         ServerAlias www.first.com         DocumentRoot /var/www         ErrorLog /var/log/first.com.err         CustomLog /var/log/first.com.log common &lt;/VirtualHost&gt;  &lt;VirtualHost _default_:*&gt;         ServerName unknown         DocumentRoot /var/www_404 &lt;/VirtualHost&gt; UK visa requirement: Residence or citizenship? On gov.uk's  it is indicated      Check if you need this visa if you’re visiting from outside the European Economic Area (EEA) or Switzerland"   “Visiting from” makes you understand that the country you regularly live in is relevant, thus you can avoid applying for a visa if you are visiting from Italy (as country of regular residency).  As a matter of fact, if you proceed to make the check, the question to answer is "What passport or travel document do you have?", not really consistent with the indication previously given.  So, what is relevant: the country you live in with regular documents (and where you leave from to visit UK) or the country of origin which issued the passport?  To be practical, a Moldovan who is an Italian resident with regular resident card and Italian ID card (but with the note "not valid for expatriation") can avoid applying for a visa if he wants to spend a week-end in London (thus visiting from inside EEA)? I'm too spoiled by Windows utilities that take a digital snapshot of your entire drive, which you can then restore from in the event of a drive crash.  (e.g. like Time Machine for Mac OS X).  Is there a similar way of doing this in Linux?