Particular example of comma after but
Comma after a coordinating conjunction preceding a parenthetical at the start of the sentence
What causes this corkscrew-shaped object to rise up in a stream of water falling down? Gradient Boosting for Linear Regression - why does it not work? Push Notification Badge Count Not Updating Is it possible to speed up the gzip process?  I'm using  mysqldump "$database_name" | gzip &gt; $BACKUP_DIR/$database_name.sql.gz   to backup a database into a directory, $BACKUP_DIR.  the manpage says:     -# --fast --best             Regulate  the  speed  of compression using the             specified digit #, where -1  or  --fast  indi‐             cates  the  fastest  compression  method (less             compression) and -9 or  --best  indicates  the             slowest compression method (best compression).             The default compression level is -6 (that  is,             biased  towards high compression at expense of             speed).    How effective would it be to use --fast? Is this effectively lowering the CPU usage on a modern computer?   My test results  I didn't notice any acceleration:   7 min, 47 seconds (with default ratio -6) 8 min, 36 seconds (with ratio --fast ( = 9 ))   So it seems it takes even longer to use the fast compression?  Only higher compression really slows it down:   11 min, 57 seconds (with ratio --best ( = 1 ))   After getting the Idea with lzop I tested that too and it really is faster:   6 min, 14 seconds with lzop -1 -f -o $BACKUP_DIR/$database_name.sql.lzo Why did the gamma ray burst from GW170817 lag two seconds behind the gravitational wave? , reporting on the announcement of gravitational wave GW170817, explained that for the first time we could identify the precise source of a gravitational wave because we also observed the event in the electromagnetic spectrum. It notes however that the gamma ray burst detected by the FERMI space telescope was observed nearly two seconds later than the gravitational wave.   Did the gamma ray burst actually arrive at Earth two seconds after the gravitational wave, or is this time delay just some kind of observational artefact? If the delay is real, what is its cause? Is the delay due to the gamma ray burst somehow being slowed, or was it 'emitted' at a different time in the merger event? What does a delay even mean when the gravitational wave was detected for over 100 seconds? Is it a delay from peak GW to peak gamma ray? Connect Java to a MySQL database Let G be a group, where $(ab)^3=(a^3)(b^3)$ and $(ab)^5=(a^5)(b^5)$. Prove that $G$ is abelian group.  Thank you in advance. Any help is appreciated. Is there anyway to restore the Blender default Cloth settings? Or is there anyway to find what the default settings are?  I didn't realize at the time that by changing the values I was overriding the default values.  Using Blender v2.76. How to tenderize large squid? My whole life I've been buying small squid (maybe 4-6" long bodies without the head and tentacles), which are very mildly chewy and tender.  All it takes is sautee them in a little OO and they are good to eat, IOW, no additional tenderizing is needed.  Yesterday I got some large squid, about 1 lb each before cleaning, probably 10"+ long without the head, probably 5-6 times as much meat as the little ones I usually get.  I remember trying to cook that before and they came out very tough and with a bit of unpleasant odor.  Is there a way to marinate and tenderize large squid and to somehow neutralize the odor? How do gas molecules constantly bounce without losing energy? From a related question (), i asked myself this: How do gas molecules constantly bounce off each other without losing energy?  If you drop a ball, it bounces a bunch of times, but the height of each bounce gets shorter and shorter. Because it loses energy in each bounce.  So I don't see how a pressurized gas doesn't lose energy. As I understand it, pressure is a manifestation of lots of molecules bouncing off each other. So over time, shouldn't the pressure drop as the molecules lose speed? and eventually all the molecules will settle in a pile on the floor.  I think another way to phrase this is, how do elastic collisions not lose any energy in the exchange? My understanding of the 2nd law of thermodynamics is that some energy is always "lost" when it's converted from one form to another, or transferred from one object to another. I.e., no transfer/conversion of energy is ever 100% efficient. Do photons lose energy due to gravitational redshift? If so, where does the lost energy go? In the gravitational redshift, the frequency of photons radiated from some source is reduced. As the energy of a photon is given by $\hbar\omega$, if the frequency is reduced where is the lost energy? How to modify an invalid '/etc/sudoers' file? An integer $a \pmod m$ has inverse if and only if $\gcd(a,m)=1$? An integer $a \pmod m$ has inverse if and only if $\gcd(a,m)=1$?  Why is this? I tried understanding it from my notes but I don't get it.  A thorough explanation would be greatly welcome.  Thanks for all the answers so far. I think my biggest problem is understanding why $\gcd(a,m)\neq1 \Longrightarrow \not\exists a^{-1}$. I'm putting some type on a path, a circle; but when I do it, the type is upside down. How can I flip it so it reads the right way up? See image below: Equivalence between least squares and MLE in Gaussian model I am new to Machine Learning, and am trying to learn it on my own. Recently I was reading through  and had a basic question.   Slide 13 says that "Least Square Estimate is same as Maximum Likelihood Estimate under a Gaussian model". It seems like it is something simple, but I am unable to see this. Can someone please explain what is going on here? I am interested in seeing the Math.   I will later try to see the probabilistic viewpoint of Ridge and Lasso regression also, so if there are any suggestions that will help me, that will be much appreciated also. siunitx tabular numbers with separated uncertainty I would like to format the space reserved for a number shown in a table with separated uncertainty. It seems that when I use the table-format option the brackets around the mantissa disappear. This is illustrated in the example below:  \documentclass{article}     \usepackage{siunitx}  \begin{document}     \begin{table}   \begin{tabular}{                   S[separate-uncertainty = true]                   S[table-format=1.1(1)e1,                   separate-uncertainty = true]                   }     {Header} &amp; {Header}\\     1.0(2)e2 &amp; 1.0(2)e2\\   \end{tabular} \end{table}     \end{document}     I have also tried to use the bracket-numbers and multi-part-units = brackets without solving this issue. Is there any workaround to center the number and keep the brackets like in the first column of the example? Related post   In Peskin and Schroeder's QFT p28, the authors tried to show causality is preserved in scalar field theory.  Consider commutator $$ [ \phi(x), \phi(y) ] = D(x-y) - D(y-x) \tag{2.53} $$ where $D(x-y)$ is the two-point correlation function,  $$D(x-y):= \langle 0 | \phi(x) \phi(y) | 0 \rangle  = \int \frac{d^3 p}{ (2\pi)^3} \frac{1}{ 2E_{\mathbf{p}}} e^{-ip(x-y)}\tag{2.50}$$  P&amp;S argued that each term in the right-hand-side of (2.53) is Lorentz invariant, since $$\int \frac{d^3p }{ (2\pi)^3} \frac{1}{2E_{\mathbf{p}}} = \int \frac{ d^4 p }{ (2\pi)^4} (2\pi) \delta(p^2-m^2)|_{p^0&gt;0} \tag{2.40}$$ is Lorentz invariant.  Since there exists a continuous Lorentz transformation in the spacelike interval $(x-y)^2&lt;0 $ such that $(x-y) \rightarrow - (x-y) $ and $D(y-x)=D(x-y)$, (2.53) equals zero in the spacelike interval. In timelike interval, since such continuous Lorentz transformation does not exist, (2.53) is non-zero in general.  My question is, consider a non-continuous Lorentz transmation in the timelike interval, $PT$, namely time reversal times parity transformation. I can also let  $(x-y) \rightarrow - (x-y) $. Why (2.53) in the timelike interval is non-zero?  I guess $PT$ will let (2.40) go to $p^0&lt;0$ branch. But I am not sure if it breaks the Lorentz invariant of (2.40) and (2.50). How to get a UK visa refund I applied online for a visa application to the UK. I'm from Sri Lanka. Yesterday I cancelled the appointment, I changed my mind. I will not go to the visa appointment. Now my question is how I get my refund? Yesterday, one of our computers dropped to grub shell or honestly, I am unsure what shell it was when we turned on the machine.  It showed that it can't mount the root filesystem or something in this sense, because of inconsistencies.  I ran, I believe:  fsck -fy /dev/sda2   Rebooted and the problem was gone.  Here comes the question part:  I already have in her root's crontab:   @reboot /home/ruzena/Development/bash/fs-check.sh    while the script contains:  #!/bin/bash touch /forcefsck   Thinking about it, I don't know, why I created script file for such a short command, but anyways...  Further, in the file:  /etc/default/rcS   I have defined:   FSCKFIX=yes    So I don't get it. How could the situation even arise?    What should I do to force the root filesystem check (and optionally a fix) at boot?  Or are these two things the maximum, that I can do?  OS: Linux Mint 18.x Cinnamon 64-bit.  fstab:  cat /etc/fstab | grep ext4   shows:   UUID=a121371e-eb12-43a0-a5ae-11af58ad09f4    /    ext4    errors=remount-ro    0    1    grub:   fsck.mode=force    was already added to the grub configuration. Is there anything special with complex fraction $\left|\frac{z-a}{1-\bar{a}{z}}\right|$?