Validation in javascript not working
How to validate an email address using a regular expression?
Improving "demonstrate a minimal understanding" close reason My account has been temporarily suspended; what does that mean? My account has been , besides the following restrictions:  an account will be locked at 1 reputation the user page will have a visual indication that the account is in timed suspension, and for how long the account holder will be unable to vote, ask, answer or comment  What else does timed suspension prevent me doing? For example, can I still edit my own posts or delete content? And what is a network-wide suspension? How to determine a matching color code from a physical sample? I need to make a restaurant menu design that matches restaurant wallpapers. For some reason my client cannot get color codes used in wallpaper, but he provided me with a sample. (see below)    How can I get the correct color codes from the wallpaper? (someone mentioned that there are scanners for this purpose, but I could not find any information regarding that)  Let me know if this question should be in another site. Parenthesis vs brackets for matrices When I first learned linear algebra, both the professor and the book used brackets like [ and ] to enclose matrices. However, in my current differential equations textbook, matrices are enclosed by parenthesis, and I suddenly realize everybody else are using them too.  So are brackets/parenthesis for enclosing matrices always totally interchangeable? How to find all the tables in MySQL with specific column names in them? A Terms of Service update restricting companies that scrape your profile information without your permission Does the refresh rate affect LCD screens? I have never really paid any attention to the refresh rate setting on computers with LCD screens.  I thought with LCD displays the pixels are either on or off, they don't flicker like in old CRT monitors.  Seems trivial to me, but my own graphics card allows me to select 59Hz or 60Hz - which leads me onto my question:  Does the refresh rate affect LCD screens?  Technical info to back up any answers would be great. I have recently been reading about Quantum Electrodynamics which I found very interesting, but even more confusing.  I understand photons mediate the electromagnetic force and interactions between charges can be described by virtual photon exchange. And that in Quantum Mechanics particles paths can be evaluated by sum over all paths...  An electron travelling from one point to another will take all paths, emitting and reabsorbing virtual photons. Does the electrons take all paths including those that involve faster than light velocities?  Is this question null, Does it mean anything to ask about properties of virtual particles?  Do I have the wrong idea about what virtual particles are? GParted can't resize partition, but unallocated partition is available Proof relation between Levi-Civita symbol and Kronecker deltas in Group Theory In order to prove the following identity: $$\sum_{k}\epsilon_{ijk}\epsilon_{lmk}=\delta_{il}\delta_{jm}-\delta_{im}\delta_{jl}$$ Instead of checking this by brute force, Landau writes thr product of Levi-Civita symbols as: $$\epsilon_{ijk}\epsilon_{lmn}=\det\left|    \begin{array}{cccc}       \delta_{il}   &amp; \delta_{im}  &amp; \delta_{in}   \\       \delta_{jl}   &amp; \delta_{jm}  &amp; \delta_{jn}   \\       \delta_{kl}   &amp; \delta_{km}  &amp; \delta_{kn}       \end{array} \right| $$  The proof that the equalty holds is quite straightforward if you consider what values the indices can take. But I've been told that there's a much more profound and elegant demonstration based on the representation of the symmetric group.  Does anybody know this approach based on group theory? Failed to start TSQL debugger I want to debug in TSQL.When I start the debug the following message box popup. In SSMS v17.2    Then I see this message:    In Microsoft Visual Studio 2015 Server Explorer same Error:    Then I see this message:    Thank You! Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms? What differentiates the scientific method from other methods From the controversy in , I would like to know what differentiates "the scientific method" from other method.  I'm asking for differentiation, rather than a definition, because definitions call for an all encompassing answer, which is often hard to find.  If someone asks "what is an alternative to the scientific method," I would like to be able to start by being able to reliably say whether a particular method is the scientific method or not.  Of course, being a linguistic issue, the definitions of words themselves are flexible.  For instance, it is not uncommon to hear one in science talk of "truth" in a sense which is incompatable with the mathematical meaning of "truth."  Accordingly, I would like to stick to the following ideals in wording whenever possible:   Prefer mathematically accurate terminology.  Ideally the word "proof" should be used in the form found in proof theory, and "true" and "false" should be used in the form of Boolean algebra.   No method should claim a hypothesis which predicts the state of the future is "true" unless they claim soothsaying abilities (most scientific theories include a random variable to avoid needing to claim soothsaying abilities... this is legitimate)  Words which imply direction should be clarified carefully.  "Good" and "bad" are notoriously difficult, but phrases such as "advancing society" can also be very tricky as well. The physical world and the world of information theory should be treated differently.  In particular, the concept of "testing a hypothesis" will likely need to be broken down into testing and observing the physical world, taking measurements (which should have errors associated with them), and only then is the hypothesis compared against the results of the measurements. Mathematically extending arguments into infinity (such as claiming some specific cellular level learning process qualifies as the scientific method) are valid, but may rapidly make it harder to distinguish non-scientific methods from scientific ones.  Such claims should be made carefully, but they are not inherently invalid.   If these ideals are too strict, you may bend them, but you should qualify such choices with an explanation of why my recommended wording choices are too strict.  Their goal is to put different methodologies on the levelest playing fields that I can manage in this medium.  Being stack exchange, bonus points for references to existing theories, though you may need to paraphrase their results to fit with the ideals I'm recommending for these answers.  Answers may be tested two ways:   Positive: If we think something is the scientific method, does it meet the requirements set forth? Negative: If we think something is not the scientific method, does the answer explain why it is not? Embedding ordinals in $\mathbb{Q}$ Transitive subgroup of symmetric group $S_n$ containing an $(n-1)$-cycle and a transposition Is there a proper way to handle large combat engagements with party members involved? For instance, a party of four player characters raise a force of 30 militia men to go take a bandit camp. When they get there the bandit camp has 40 men, and none of them notable.  For the sake of simplicity, both the 30 men and the 40 bandits are armed with long swords, and wearing leather armor.   Is there a proper way to handle combat between the 30 man militia and the 40 bandits while also incorporating our four player characters? If no "proper" way exists, is there a generally accepted "best" way? I bought two pieces of land. One from Morthal, and one from Falkreath. Morthal was the first plot of land I purchased. I only finished half of it. I bought the plot of land in falkreath because I liked the nature better. I finished the house completely in Falkreath. Every time I try to adopt a child off the streets it keeps saying "I have a place but no room for you" Even though I have the bedrooms in my Falkreath house. Why can I not adopt a child and have him/her live at my house in Falkreath? How to simulate data that satisfy specific constraints such as having specific mean and standard deviation? This question is motivated by . But I imagine that it would also be useful in teaching contexts where you want to create a dataset that exactly mirrors an existing published dataset.  I know how to generate random data from a given distribution. So for example, if I read about the results of a study that had:   a mean of 102, a standard deviation of 5.2 , and  a sample size of 72.   I could generate similar data using rnorm in R. For example,   set.seed(1234) x &lt;- rnorm(n=72, mean=102, sd=5.2)   Of course the mean and SD would not be exactly equal to 102 and 5.2 respectively:  round(c(n=length(x), mean=mean(x), sd=sd(x)), 2) ##     n   mean     sd  ## 72.00 100.58   5.25    In general I'm interested in how to simulate data that satisfies a set of constraints. In the above case, the constaints are sample size, mean, and standard deviation. In other cases, there might be additional constraints. For example,    a minimum and a maximum in either the data or the underlying variable might be known. the variable might be known to take on only integer values or only non-negative values. the data might include multiple variables with known inter-correlations.   Questions   In general, how can I simulate data that exactly satisfies a set of constraints? Are there articles written about this? Are there any programs in R that do this? For the sake of example, how could and should I simulate a variable so that it has a specific mean and sd? Currently using ubuntu 15.10 on azure and installed the gnome and vnc4server latest version on ubuntu. Please find log file below:  Current VNC client screen:    $ cat .vnc/myhost1\:1.log    --cut-- VNCSConnST:  Server default pixel format depth 16 (16bpp) little-endian rgb565 VNCSConnST:  Client pixel format depth 8 (8bpp) colour-map Window manager warning: Invalid WM_TRANSIENT_FOR window 0x20000c specified for    0x20000b (I        nitialization error). Error org.freedesktop.DBus.Error.NameHasNoOwner: Could not get owner of name    'org.gnome.ze        itgeist.Engine': no such name amdxdg-su: no graphical method available for invoking '/usr/bin/amdcccle' as 'root'  $ cat .vnc/xstartup unset SESSION_MANAGER  [ -x /etc/vnc/xstartup ] &amp;&amp; exec /etc/vnc/xstartup [ -r $HOME/.Xresources ] &amp;&amp; xrdb $HOME/.Xresources  vncconfig -iconic &amp;  gnome-panel &amp; gnome-settings-daemon &amp; metacity &amp; nautilus -n &amp; gnome-terminal &amp;   How to get 24bit color with wide screen (Now I getting square screen in vnc client) I seem to have run into a bit of a challenge on one of our Android/Samsung devices...   On the device, regardless of what's open, when the battery reaches 25% on discharge, the below screen pops up and covers the entire screen, with MUCH difficulty to get rid of. I've tried to trace it to a certain app, but was unsuccessful in doing so.     Can someone perhaps help with some advice on this, on how to get rid of it?