A magnetic field could not be induced unless there is a time varying electric flux associated with the amperial loop under consideration. But a well known field exists around a current carrying conductor. Then how can we say that electric field is absent around the conductor.
Can a magnetic field be induced without an electric field? Because, as far as I know, a time varying electric field induces a magnetic field an vice versa.  But in the case of conductors carrying currennt, it doesn't seem that electric field varies with time, then how is a magnetic field induced?
How to create a separate subnet for wireless access? I need to configure my wireless router so all wireless devices are on a different subnet (192.168.2.1).  The wireless devices should be able to access the internet, but ideally not the workstations on the LAN.  Here is my network:    All suggestions welcome! Any practical uses of machine learning for cryptography? Why is angular velocity of any point about any other point of a rigid body always the same? I have the following question regarding an ideal rigid body.  Firstly, is it always true without any exceptions that the angular velocity of any point about any other point on a rigid body is always the same?  If so, what happens in case of precession, in which two different angular velocities are predefined? Will stationary charge radiate E.M waves if observer is accelerating? Crash course on algebraic geometry with view to applications in physics Could you please recommend any good texts on algebraic geometry (just over the complex numbers rather than arbitrary fields) and on complex geometry including Kahler manifolds that could serve as an informal introduction to the subject for a theoretical physicist (having in mind the applications in physics, e.g. in the string theory)?   What I want for a moment is to get some informal picture of the subject rather than being dug up into the gory details of the proofs and lost in higher and higher layers of abstraction of commutative algebra and category theory. The texts I have found so far are all rather dry and almost completely lack this informal streak, and all of them are geared towards pure mathematicians, so if there exists something like "Algebraic geometry for physicists" and "Kahler manifolds for physicists" (of course, they would probably have different titles :)), I would greatly appreciate the relevant references. Is it possible to to take a screenshot of a webpage with JavaScript and then submit that back to the server?  I'm not so concerned with browser security issues. etc. as the implementation would be for . But is it possible? Tokenizing strings in C I have been trying to tokenize a string using SPACE as delimiter but it doesn't work. Does any one have suggestion on why it doesn't work?  Edit: tokenizing using:  strtok(string, " ");   The code is like the following  pch = strtok (str," "); while (pch != NULL) {   printf ("%s\n",pch);   pch = strtok (NULL, " "); } Increasing real valued function whose image set is connected Let $S = [0,1) \cup [2,3]$ and $f\colon S \rightarrow \mathbb R$ be such that $f(S)$ is connected . Which of the following are true:  a) $f$ is discontinuous exactly at one point.  b) $f$ is discontinuous exactly at two points.  c) $f$ is discontinuous at infinite many points.  d) $f$ is continous.  I think $f$ is continuous . We need to show that $\lim_{x \to a^+}f(x) = f(a)$ for any $a \in S$. Since $f(x)$ is increasing, $\lim_{x \to a^+}f(x) \leq f(a)$. Suppose $\lim_{x \to a^+}f(x) &lt; f(a)$. Then there is $l$ such that $\lim_{x \to a^+}f(x) &lt; l &lt;f(a)$, which contradicts connectedness of $f(S)$. Similarly we can show that $\lim_{x \to a^-}f(x) = f(a)$.  I would be thankful if anyone would check my solution and correct me if there are any errors. how to display the actual network traffic (wireless) in a terminal?  Additionally: Is it possible to add this info to the chart of top? Add the font changes as options in our preferences Are battery packs allowed in hand luggage? Comparing mixed-effects and fixed-effects models (testing significance of random effects) Given three variables, y and x, which are positive continuous, and z, which is categorical, I have two candidate models given by:  fit.me &lt;- lmer( y ~ 1 + x + ( 1 + x | factor(z) ) )   and  fit.fe &lt;- lm( y ~ 1 + x )   I hope to compare these models to determine which model is more appropriate. It seems to me that in some sense fit.fe is nested within fit.me. Typically, when this general scenario holds, a chi-squared test can be performed. In R, we can perform this test with the following command,  anova(fit.fe,fit.me)   When both models contain random-effects (generated by lmer from the lme4 package), the anova() command works fine. Owing to boundary parameters, it is normally advisable to test the resulting Chi-Square statistic via simulation, nonetheless, we can still use the statistic in the simulation procedure.  When both models contain only fixed-effects, this approach---and, the associated anova() command---work fine.  However, when one model contains random effects and the reduced model contains only fixed-effects, as in the above scenario, the anova() command doesn't work.  More specifically, I get the following error:   &gt; anova(fit.fe, fit.me)  Error: $ operator not defined for this S4 class   Is there anything wrong with using the Chi-Square approach from above (with simulation)? Or is this simply a problem of anova() not knowing how to deal with linear models generated by different functions?  In other words, would it be appropriate to manually generate the Chi-Square statistic derived from the models? If so, what are the appropriate degrees of freedom for comparing these models? By my reckoning:  $$ F = \frac{\left((SSE_{reduced}-SSE_{full})/(p-k)\right)}{\left((SSE_{full})/(n-p-1)\right)} \sim F_{p-k,n-p-1} $$  We are estimating two parameters in the fixed effects model (slope and intercept) and two more parameters (variance parameters for the random slope and random intercept) in the mixed-effects model. Typically, the intercept parameter isn't counted in the degrees of freedom computation, so that implies that $k=1$ and $p=k+2=3$; having said that I'm not sure if the variance parameters for the random-effects parameters should be included in the degrees of freedom computation; the variance estimates for fixed-effect parameters are not considered, but I believe that to be because the parameter estimates for fixed effects are assumed to be unknown constants whilst they are considered to be unknowable random variables for mixed effects. I would appreciate some assistance on this issue.  Finally, does anybody have a more appropriate (R-based) solution to comparing these models? Where can you find the quantities of each amino acid of a particular protein or food? I need backup in pressing my case that the phrase “choose from one of four options” is grammatically incorrect. Is there some resource that can prove my case, that the incorrect phrase should be replaced with one of the two following ones?        Choose one of four options   Choose from four options LaTeX package for syntax highlighting of code in various languages I am looking for a LaTeX package that does syntax highlighting on code. For example, right now I use the verbatim block to write code:  \begin{verbatim}     &lt;html&gt;        &lt;head&gt;            &lt;title&gt;Hello&lt;/title&gt;        &lt;/head&gt;        &lt;body&gt;Hello&lt;/body&gt;     &lt;/html&gt; \end{verbatim}   And this works fine to display the code on my document. But, suppose I wanted to highlight the HTML markup the way an IDE would in the output document? Is there a package that could help?  I would like to do the same for various languages such as Java, C#, HTML, CSS and so on. Where's the energy in a boosted capacitor? Suppose I look at a parallel plate capacitor in its rest frame and calculate the electrostatic energy, $E$.  Next, I look at the same capacitor in a primed frame boosted in the direction perpendicular to the plane of the plates. In this frame, the $E$-field is the same strength, there is no magnetic field, and the volume over which the $E$-field extends is less by a factor $1/\gamma$. This suggests $E' = \frac{1}{\gamma} E$, but relativity states that energy transforms as $E' = \gamma E$.   Where is the missing energy? Ring of fractions of $R$ is integral over $R$ Let $R$ be a commutative ring and let $S\subseteq R$ be a multiplicative closed subset containing 1.     I need to show that if $S^{-1}R$ is integral over $R$, then $S^{-1}R=R$.   I don't see how to get started. I'm using Apache JMeter 2.3, which now supports "attempt HTTPS spoofing" under the Proxy Server element.   I've tried this on several different servers, and have had no success.  Has anyone been able to successfully record from an HTTPS source with this setting?  Or barring successfully recording, can anyone share a work-around? When available, I simply have HTTPS turned off at the server level, but this is not always feasible. Thoughts? Can not create SFTP user Debian 7 I have a linode and I access via ssh throw terminal. I need to create an sftp user which his default directory (and the only he can access) is /var/www/xxxxxx.com/public_html/directory  Now, I did it, but when I try to connect I get broken pipe or connection rejected by peer  What I did is this:  $ adduser --home /var/www/xxxxxx.com/public_html/directory/ username $ chown username:username /var/www/xxxxxx.com/public_html/directory/ $ chmod 755 /var/www/xxxxxx.com/public_html/directory/ $ nano /etc/ssh/sshd_config   In /etc/ssh/sshd_config I added the following lines  Match User username    ChrootDirectory /var/www/xxxxxx.com/public_html/directory/    AllowTCPForwarding no    X11Forwarding no    ForceCommand internal-sftp   What am I doing wrong?  EDIT: This is the actual error    EDIT2: this is the error in filezilla    EDIT 3: auth.log   Oct 15 17:47:11 (none) sshd[361]: fatal: bad ownership or modes for chroot directory "/var/www/xxxxxxxxxxxx.com/public_html/extras_html" What is the term for a sentence which reads same forwards and backwards? Please note, I'm not asking for a palindrome.  I mean to say that only the word  order is rearranged, not the actual spelling of the word.  An example might be as follows:     First ladies rule the State and state the rule: ladies first.