Bug in mobile view I've spotted a bug in the mobile view of the network. It's near the notification box and the achievement tracker (top right corner):    Those who are used to the mobile view, would be knowing that previously, the "1" or any number would completely hide the notification box, and the "+5" or any such number would completely honest the achievement tracker symbol. Currently these have moved to the right.  Hope that the site developers will look into this.
Inbox notification and reputation score is misaligned in mobile web view The inbox notification indicator and reputation score indicator are misaligned in the mobile web view.
FaceTime not working on iPhone 6 Plus purchased from Dubai I bought my iPhone 6 Plus in Dubai. I am using the phone in Sri Lanka and I cannot use the FaceTime. How can I use FaceTime while in Sri Lanka? Debian based system, only one gui program, nothing else I would like to make a debian system where you can only open one GUI program at boot, no other graphical interface, no minimize, or any X apart from that program, is there a way to do it on debian if possible, or any other custom distro? I just want to boot open the program and allow the user to only see and use that program. During Thor's interrogation, Agent Coulson exits the room and Loki enters and informs him that his father Odin had passed away and that he cannot undo his banishment. Not only does he communicate with Thor, but he goes to the area where Mjölnir is embedded in the rock and attempts to lift it, with SHIELD scientists and agents completely oblivious to his presence. Loki shows a similar ability when he converses with 'The Other' and when he manipulates Erik Selvig. Is this a part of Loki's illusion powers or another one of his abilities that has not been addressed? How was he able to visit Earth without using the Bifrost? If replicators allowed humans to stop working, why were replicators shut down in the Voyager? Run VirtualBox in background, without a window? I was wondering if it's possible to run an Ubuntu virtual machine using VirtualBox in background, I mean, without any window open.  The idea is to connect via SSH to the Linux host, that would be running in background.  Has anyone ever done something like this? Is it possible? Suppose we want to define a first-order language to do set theory (so we can formalize mathematics). One such construction can be found . What makes me uneasy about this definition is that words such as "set", "countable", "function", and "number" are used in somewhat non-trivial manners. For instance, behind the word "countable" rests an immense amount of mathematical knowledge: one needs the notion of a bijection, which requires functions and sets. One also needs the set of natural numbers (or something with equal cardinality), in order to say that countable sets have a bijection with the set of natural numbers.  Also, in set theory one uses the relation of belonging "$\in$". But relation seems to require the notion an ordered pair, which requires sets, whose properties are described using belonging...  I found the following in Kevin Klement's,  (pages 2-3).  "You have to use logic to study logic. There’s no getting away from it. However, I’m not going to bother stating all the logical rules that are valid in the metalanguage, since I’d need to do that in the metametalanguage, and that would just get me started on an infinite regress. The rule of thumb is: if it’s OK in the object language, it’s OK in the metalanguage too."  So it seems that, if one proves a fact about the object language, then one can also use it in the metalanguage. In the case of set theory, one may not start out knowing what sets really are, but after one proves some fact about them (e.g., that there are uncountable sets) then one implicitly "adds" this fact also to the metalanguage.  This seems like cheating: one is using the object language to conduct proofs regarding the metalanguage, when it should strictly be the other way round.  To give an example of avoiding circularity, consider the definition of the integers. We can define a binary relation $R\subseteq(\mathbf{N}\times\mathbf{N})\times(\mathbf{N}\times\mathbf{N})$, where for any $a,b,c,d\in\mathbf{N}$, $((a,b),(c,d))\in R$ iff $a+d=b+c$, and then defining $\mathbf{Z}:= \{[(a,b)]:a,b\in\mathbf{N}\}$, where $[a,b]=\{x\in \mathbf{N}\times\mathbf{N}: xR(a,b)\}$, as in  question or  on Wikipedia. In this definition if set theory and natural numbers are assumed, then there is no circularity because one did not depend on the notion of "subtraction" in defining the integers.  So my question is:     Question Is the definition of first-order logic circular?   If not, please explain why.   If the definitions are circular, is there an alternative definition which avoids the circularity?   Some thoughts:   Perhaps there is the distinction between what sets are (anything that obeys the axioms) and how sets are expressed (using a formal language). In other words, the notion of a set may not be circular, but to talk of sets using a formal language requires the notion of a set in a metalanguage. In foundational mathematics there also seems to be the idea of first defining something, and then coming back with better machinery to analyse that thing. For instance, one can define the natural numbers using the Peano axioms, then later come back to say that all structures satisfying the axioms are isomorphic. (I don't know any algebra, but that seems right.) Maybe sets, functions, etc., are too basic? Is it possible to avoid these terms when defining a formal language? I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out? Dropping one of the columns when using one-hot encoding Is there a HTML opposite to ? Is there a tag in HTML that will only display its content if JavaScript is enabled? I know &lt;noscript&gt; works the opposite way around, displaying its HTML content when JavaScript is turned off. But I would like to only display a form on a site if JavaScript is available, telling them why they can't use the form if they don't have it.  The only way I know how to do this is with the document.write(); method in a script tag, and it seems a bit messy for large amounts of HTML. I know that electromagnetic waves induce electric currents in conductors and that's the basis for radio, wi-fi etc.  I also know that light is also an electromagnetic wave. So, can light induce a current in a conductor (like a metal wire? or a coil?). And, if the answer is yes, is the same visible for other high-frequency waves (X-rays, gamma)?  I heard about the photoelectric effect, but it seems related to the particle theory of light (photons transferring their energy to electrons).  So, do high-frequency electromagnetic waves generate electric currents? Is it possible to measure them? Is the skin effect relevant here? How do I find packages to install via apt-get I have been denied a visa several times in a row. How does one deal with such serial refusals? Over the course of time here on TSE, I have observed individuals whose pattern of visa applications is best described as ''...     serial refusals - Two or more consecutive visa refusals issued by the same regime to the same person. Commonly for the same, or nearly the same, reasons. In some visa regimes Serial refusals can have a cumulative effect wherein the applicant's credibility is increasingly eroded, especially when the application pattern suggests a secondary agenda.   A common thread appears to be the need to visit the destination country (especially Schengen, the USA, or the UK) with a special sense of urgency. Also common in these cases are the following types of questions...   Should I just reapply once again? What are my chances? What can I do to improve my odds in the future? Can I somehow address the previous refusals to avoid them being a burden on all future applications? How can I break the pattern?      NB: This question is intended as a canonical about serial refusals. I have never been personally denied a visa. The "correct" way to write a set without a specific element is as follows: $S \setminus \{s\}$  But in some contexts this is cumbersome to write/type or read, and it detracts from the flow of the writing. Is it acceptable to just use $S \setminus s$?  Edit: By "cumbersome" i mean they look bad when you're trying to inline formulas in LaTeX. During this travel ban (COVID) can my wife come visit me in the USA? I know I can visit there but not sure about her coming here Can md5 be used for encrypting data? I know that md5 shouldn't be used for password hashing because of collisions and possibility of making dictionary attacks e.g. using rainbow tables. But what about other uses? Can I use md5 for encrypting data?  Say, attacker gains access to database where sensitive data was stored using md5. He wants to know just this data that was hashed, not another data that gives this hash. Can he do it?  I know that there are better cryptographic hash functions so don't suggest to use them if md5 is enough. I am having problems with the su command. I know my password and I am typing it correctly but su indicates authentication failure.  So I checked on the internet and then went into recovery mode and changed my username's password to what I was entering before.  Even now entering the same password on su gives me authentication failure.  Please suggest what am I doing wrong?? Possible Duplicate:          Consider the field extension $\mathbb{Q}(\sqrt2)$. I want to show that $\sqrt5 \notin \mathbb{Q}(\sqrt2)$. If this were not the case, then we could write $\sqrt5 = a + b\sqrt2$ for $a,b\in\mathbb{Q}$. However, I do not see the contradiction here. Is there a better/easier way to prove this? From this  by orlp:     If I strap a rocket booster to a rocket in space and fire it for one second, then the work provided is much higher when the rocket is flying fast compared to when the rocket was stationary. In both cases the rocket fires for the same duration but in the former case the rocket travels a much greater distance during this period. What gives? How to make program autostart only in GNOME I use both GNOME and KDE SC. In GNOME, I use Docky but I do not use it with KDE. So, I would like Docky to start up only when I login into GNOME not KDE. In KDE, there is an option to make a program autostart only in KDE. But I cannot find any such option in GNOME.    How can I do this?    Thanks in advance. I am writing a doctoral thesis and I am using  to set the references in APA (American Psychological Association) format. Mostly this has worked perfectly fine, but I would like to suppress the author initials from the compiled version (in-text, not in the end references section). This happens because there are multiple authors with the same name e.g.,     Smith and Jones (1992) or Wells and Smith (1901)    are typeset in-text as:      I. Smith and Jones (1992) or Wells and D. Smith (1901).   Although it may be correct to have the initial in-text in APA format, in reality I am using BPS (British Psychological Society) format, which uses an adapted APA format (and you guessed it, they don't like the initial in text). Thus in-text should look like the first example above (without initial) but looks like the second (with).  To clarify: Any ideas on how to suppress the initial in-text in apacite?  Thanks.  ps. I understand that I could do it with a different bibtex style, but my question pertains to apacite.