why is the placement of the table wrong?
How to influence the position of float environments like figure and table in LaTeX?
I have a quite wide monitor and it's quite annoying to see the login dialog in the login screen on the far left side of my screen. I literally have to turn my head around to look at it!  Is there a way to center the login dialog? What is the name of this kind of character illustration? Can any one tell me the advantage of synchronized method over synchronized block with an example? prove that if $E$ is connected and $E \subseteq F \subseteq \overline{E}$, then $F$ is connected. Define a set $A$ to be disconnected iff there exist nonempty relatively open sets $U$ and $W$ in $A$ with $U\cap W = \emptyset$ and $A = U\cup W.$ Define a set $A$ to be connected iff it is not disconnected.(there are many equivalent definitions, but I want to prove this lemma using this one). Prove that if $E$ is connected and $E\subseteq F \subseteq \overline{E},$ then $F$ is connected.  Let $U, W$ be a separation for $F$. Find open sets $O_U$ and $O_W$ so that $U = F \cap O_U$ and $W = F\cap O_W.$ I claim that $E\cap O_U, E\cap O_W$ separate $E$. However, I'm unable to show that $U' = E\cap O_U, W' =E\cap O_W \neq \emptyset$ (I think this should be straightforward, but for some reason, I can't figure this out). Suppose $U' = \emptyset.$ Then $E\cap O_U = \emptyset.$ Since $E \subseteq F = U\cup W = F\cap (O_U \cup O_W)\subseteq O_U\cup O_W,$ we have that $E \subseteq O_W,$ so $E\cap O_W = E\subseteq F\cap O_W = W\subseteq F\subseteq \overline{E}.$ Observe that since $E\cap O_U = \emptyset, F\cap O_U = (F\backslash E)\cap O_U\subseteq F\backslash E.$ Similarly, $W'\neq \emptyset.$ Clearly, $U', W'$ are relatively open in $E$. Suppose $U'\cap W' \neq \emptyset.$ Let $x\in U'\cap W'.$ Then $x\in E\cap O_U\cap O_W \subseteq F\cap O_U\cap O_W = U\cap W = \emptyset,$ a contradiction. So $U'\cap W' = \emptyset.$ Also, $U'\cup W' = (E\cap O_U)\cup (E\cap O_W) = E\cap (O_U \cup O_W)$ and $E\subseteq (O_U \cup O_W),$ so $U'\cup W' = E.$ What are the options for managing multiple Ubuntu installations together and keeping them in same state Recently I got in charge of managing 2 computer labs (currently 35 workstations, could double in a month or two) in university with total control over software stack as long as I install a bunch of commonly used scientific software (Mathematica and friends).  I plan to use Ubuntu for various reasons.   Installing Ubuntu and managing updates etc by hand is certainly an option, But I want to know if there is a more efficient way to do this stuff in and a more "Don't Repeat Yourself" manner?  Tasks   Ubuntu installation Installation (duplication) of same software stack and configuration over each workstation Keeping them updated Install suspension forks on non-suspension bike Can virtual particles be thought of as off-shell Fourier components of a field? I just found  blog post, which gives an interpretation of virtual particles I haven't seen before.  Consider a 1D system of springs and masses, where the springs are slightly nonlinear. A "real particle" is a regular $\cos(kx-\omega t)$ wavepacket moving through the line, where $\omega$ satisfies the dispersion relation $\omega = \omega(k)$. When two real particles collide, the region where they collide temporarily looks really weird, as they interact nonlinearly, pulling and pushing on each other.  Formally, we can write this weird region as the sum of a bunch of $\cos(kx-\omega t)$ waves, but there's no guarantee they'll have the right dispersion relation. Thus, each term in the resulting expansion is a off-shell "virtual particle". If you add up all the virtual particles, you get the actual intermediate field state, which is just a weird ripple in the field where the two particles are interacting.  As another example, consider the statement "a static EM field is made of virtual particles". Under this interpretation, what that really means is, "a static field (e.g. $1/r^2$) is not equal to $\cos(kx-\omega t)$, but may be expanded in terms of such sinusoids", which is much less mysterious sounding. In fact, this is exactly what we do when we consider scattering off a potential in normal QM, e.g. in the Born approximation.  The above gives some intuition for what a 'virtual particle' means in classical field theory. They are the Fourier components of the field with $(\omega, k)$ not satisfying the dispersion relation, and they are useful in classical perturbation theory. However, they are not propagating degrees of freedom, so they only appear during interactions.   The picture above is entirely classical. Does this picture generalize to quantum field theory, giving a physical intuition for virtual particles there? How to find architecture of my PC and Ubuntu? Making a Laser in Cycles - Straight Beam of Light? Should I use "who" or "which" when referring to a specific animal species? I'd like to know what option to use, specifically when referring to a species by its scientific name. Is there a difference between installing an application via Ubuntu Software Center or a terminal? Etiquette on sending a thank you e-mail to respondents who gave me helpful information What happens when a field turns on or off? Short Setup  I am curious about the the mechanics of fields, whether , , etc.  So as a specific example in order to simplify (hopefully) how to ask this question, consider  or , specifically interactions between .  My specific curiosity is in how we handle the "sudden" creation or loss of a source and how the source then creates its associated field.  My naive guess is that the loss of a source (e.g., annihilation) might be easier to handle, but let's focus on creation of a source for now.  Questions  The specific example of pair production interested me because I was wondering:   How does the field arise from the sources?   Meaning, is it delayed until after the source  fully "condenses" from the , for instance? Or does the field slowly "turn on" as the source "condenses"?   Perhaps I should have asked whether it we know if it takes time for sources to form (I assume it does).  If so, can we describe this from first principles or is it empirically based?  Am I asking that in a very uncomfortable manner?  If so, I would appreciate any suggestions.  For instance, is there a better word than "condense"?  I was thinking about water condensation as a very loose analogy to the purpose of the Higgs field in the formation of massive objects.  Why can they be produced without immediately recombining?   That is, how "close" are the two sources spatially after formation and what energies are needed to overcome the associated potential?  Does the field emanate/propagate as if from a point source?   I ask because I am trying to determine whether this is a simple  issue (i.e., far away it's just like a point source) or if the field emanates only from the "surface" of the source (e.g., ). If it starts from "within" the source as the source forms, do we know how to handle this mathematically?   My concern arises from the "similar" problem of bubble formation, where the bubble starts with zero radius which would require an infinite energy.  Perhaps the analogy is not appropriate?     Purpose  I ask these questions because it struck me this morning, while driving to work, that I did not know how and when a field "turned on."  I started to think about pair production and then quickly became confused (not difficult to do) and thought many of the quantum whisperers on this site would be much better at explaining these nuances than any of my failed rummaging through Wikipedia or scholarly articles and old text books. how can i display the latest items from another site collection I have a web application, with three site collections . and i want inside my team site to be able to display the latest pages that  have been added to my enterprise wiki site collection. so what are the available approaches which i can follow?  Thanks in advance for any help.  Regards I would like to have a similar biblatex behaviour as described , i.e. separate bibliographies for different publication types, each bibliography should 1) be prefixed with a corresponding label (C for conference publications, J for journals etc), 2) sorted so that the newest entry is at the top (defined by the publication year) and 3) with reference numbers sorted in descending order per bibliography, i.e. the newest entry should have the highest number.  Journal articles ---------------- [J3]    reference from 2017 [J2]    reference from 2016 [J1]    reference from 2015  Conference publications ----------------------- [C4]    reference from 2017 [C3]    reference from 2017 [C2]    reference from 2016 [C1]    reference from 2015   I currently have the following:  \usepackage[backend=biber,         isbn=true,         giveninits=true,         style=numeric,         maxnames=99,         sorting=ydnt,         defernumbers=true,         autocite=superscript]{biblatex}  \subsection*{Journal articles} \begin{refcontext}[labelprefix=J] \printbibliography[type=article] \end{refcontext}  \subsection*{Conference publications} \begin{refcontext}[labelprefix=C] \printbibliography[type=inproceedings]   Separate bibliographies works fine, labelprefix also works as desired, sorting by year in descending order as well. However, if I try the solution mentioned in the above question I get very high reference numbers (in the 500s).  Is the above behaviour possible at all and, if yes, what is the most elegant solution using current biblatex etc.?  Thanks a lot in advance! For every matrix $A\in M_{2}( \mathbb{C}) $ there's  $X\in M_{2}( \mathbb{C})$ such that $X^2=A$? Get the newest file from directory structure year/month/date/time I store backups of databases in a directory structure  year/month/day/time/backup_name  an example would be   basics_mini/2012/11/05/012232/RATIONAL.0.db2inst1.NODE0000.20110505004037.001 basics_mini/2012/11/06/012251/RATIONAL.0.db2inst1.NODE0000.20110505003930.001  note that timestamp from the backup file cannot be used. Before the automation testing starts the server time is set to 5.5.2011  So the question is how I can get the latest file if I pass the "base directory" (basics_mini) to some function that I am going to code.  I need to restore the newest database. I do that in php but I wonder if there is a simple shell scripting solution. How should I refer to a friend who is a girl but not a girlfriend? When I'm talking about my friend, who is a girl, but not a girlfriend, what word or phrase should I use? If the gender was unimportant, it would not be a problem. But if I want to note that the friend is female, not male, how should I say that, to avoid ambiguity? What tools and technologies are used to build the Stack Exchange Network?  See also: $A_4$ has no subgroup of order $6$? Can a kind algebraist offer an improvement to this sketch of a proof?     Show that $A_4$ has no subgroup of order 6.     Note, $|A_4|= 4!/2 =12$. Suppose $A_4&gt;H, |H|=6$. Then $|A_4/H| = [A_4:H]=2$. So $H \vartriangleleft A_4$ so consider the homomorphism $\pi : A_4 \rightarrow A_4/H$ let $x \in A_4$ with $|x|=3$ (i.e. in a 3-cycle) then 3 divides $|\pi(x)|$ so as $|A_4/H|=2$  we have $|\pi(x)|$ divides 2 so $\pi(x) = e_H$ so $x \in H$ so $H$ contains all 3-cycles but $A_4$ has $8$ $3$-cycles $8&gt;6$, $A_4$ has no subgroup of order 6.