In indirect speech we generally backshift the tense. For ex - Direct speech : "I am the most powerful person." Indirect speech : "He said that he was the most powerful person."  What if someone reports like -  He denied the charges claiming that he is/was the most powerful person. So here which is correct- is or was ?  Thanks in advance.
In the sentence: "I didn't know she had a son,"   Can I say "I didn't know she has a son" instead, because he is a teenager now?  Or are both correct?
Answer draft is lost if you click to sign up Adding dynamic graphics to an animation If $a^{n}-1$ is prime then $a=2$ and $n$ is prime? How does carbon dioxide or water vapour absorb thermal infra red radiation from the sun? We are all told at school water vapour and carbon dioxide are the top two greenhouse gases, and that they absorb thermal infra red radiation, trap heat and warm up the Earth. My question is how do they do that? Why can't Oxygen or Nitrogen or any other gas not absorb infra red radiation as well as water vapour or CO2? Installing Ubuntu from a partition on internal drive I am about to install Ubuntu on my new laptop, but I don't have access to a USB drive of any sort and it doesn't have an optical drive. Would it be possible to boot into the Ubuntu installer if I save it to a new partition on my hard drive and boot from there via the BIOS?  In case you need it, , which lists my system specifications.  Thanks in advance for any assistance you may be able to provide. :) I've been using SSH Tunnel manager to easily set up and stop port tunneling over SSH to various servers at my company. That saved me the pain of opening up a new terminal window which will hang out there just for the sake of having a tunnel open.  This worked great (well , sort of) but SSH Tunnel Manager is a PowerPC application. With Lion, it is not supported any more.  What is a good replacement? How can I grep in PDF files? Is there a way to search PDF files using grep, without converting to text first in Ubuntu? Animation Blending Basics Say I have a framework with characters that can run and walk and of course, stand still.  Am I right in thinking that animation blending is the process of smoothly transitioning between these by generating dynamic animations at runtime?  If so, what is the basic theory of how this works, and how would I implement it? how to sort file by DD-MM-YYYY dates in a file containing :  ... 18-11-2018:othercharacters 10-11-2018:othercharacters 03-10-2018:othercharacters 30-10-2018:othercharacters 27-09-2018:othercharacters 03-12-2018:othercharacters ...   the command :  sort -t- -k2 -k1    does not sort by date, what am I missing ? We sometimes buy trout from a local breeder who'll get them fresh out of the water for us, and then cook them a few hours later. They taste great, but the flesh tends to fall apart in a way that doesn't happen with fish from the super market. It's often barely even possible to get them out of the pot without them completely coming apart. We tried leaving them in the fridge for a day so they wouldn't be quite as just-killed-an-hour-ago-fresh, but that didn't help.   We usually prepare them by cooking them in simmering (not boiling) water.  Is there some way to prevent this? So I've been pulling my hair out over this for the last couple days now, I can't seem to find any solutions that work. I've fresh installed Ubuntu Gnome 16.04 on my system which has no other OS's running on it. Everything's fine aside from the fact that the default Nouveau display driver seems to be causing the UI to freeze sporadically every now and then. No problem right? Just install the proprietary drivers for my GPU and we should be golden? Well here's the thing, no matter how I try to get my GPU's drivers installed I always seem to hit some sort of issue. Here's what I've tried so far:   Switch to the proprietary driver from within the 'Software &amp; Updates' app in Ubuntu. For me the only option available is the 'NVIDIA binary driver - version 375.66 from nvidia-375 (proprietary, tested)'.    After selecting this driver it goes through the install process, asks me to 'configure secure boot' by entering a password, etc. This all seems to work fine initially until I reboot, but then before I see the login screen it seems to open a virtual terminal (usually accessed via alt+shift+F1), but then immediately boots me back to a black screen where it will flash this terminal for a split second every 4 seconds or so. I can access this terminal by using alt+shift+F1, and go on to use it as normal, but it will continually boot me back out to the black screen every few seconds. The only way I can solve this is to keep accessing the terminal each time it boots me out while I purge the nvidia drivers using sudo apt purge nvidia-*. After purging I'm then able to access the login screen and access my Ubuntu again as normal, besides having to reboot to presumably activate the Nouveau drivers again otherwise the resolution is all messed up and only one of my three monitors has anything displayed on it.    Using the steps listed  I download the latest stable/certified driver for my GPU (which as of writing this is version 384.69). However on step 3 where it instructs me to run the driver using sudo sh, I reach an issue where the installer informs me that I need to disable the Nouveau driver in order to continue. I've tried everything from uninstalling Nouveau using 'sudo apt-get remove --purge xserver-xorg-video-nouveau` to blacklisting Nouveau using the steps listed , by editing the 'nvidia-graphics-drivers.conf'.    Unfortunately no matter what I do to try and disable Nouveau the installer always informs me that the Nouveau driver is enabled and needs to be disabled in order to continue. What's funny is that I managed to install the driver using this method once before, but for the life of me I can't get it to work again.    Finally, I've attempted to install the driver by installing the PPA. I run sudo add-apt-repository ppa:graphics-drivers/ppa, sudo apt update, and finally going back into the 'Software &amp; Updates' app and select the 384.69 driver. However after going through the install process the same issue as described in my first method (1.) occurs.    I've also tried switching between gdm3 and lightdm with all 3 methods to no avail. I'm at a complete loss as to what to do. If anyone has any possible solutions I'd love to hear them, because right now I'm at the end of my tether.   If you require any further information just let me know and I'll be more than happy to provide it.   System info:   AMD FX-8350  Nvidia GeForce GT710 1gb  16gb RAM  Ubuntu Gnome 16.04 LTS While studying rotational mechanics, I came across a section where it mentioned that angular momentum may not necessarily be parallel to angular velocity. My thoughts were as follows:  Angular momentum ($L$) has the relation $L=I\omega$ where $\omega$ is angular velocity and $I$ is the moment of inertia, so following this relation, it seems they should be in the same direction. Why are they not? Variance of product of multiple independent random variables Ubuntu 18.04 can't resume after hibernate Hibernate worked correctly when I had been using Ubuntu 17.04. After upgrade to 17.10 I couldn't resume because of black screen after resume ().   After upgrade to 18.04 if I try to start my computer after hibernation it boots as if there was no hibernation done. Allow bounty to be set with reputation from another site? For almost a year now, I have been in the uncomfortable position of having an idea.  However, there is one nice thing about this idea.  It makes a concrete, exact and relatively easy to test physical prediction.  The idea predicts that there is a 11,187 m/s (Earth’s escape velocity) aethereal wind directly into the surface of the Earth at its surface.  I believe it would be possible to test this by performing a vertical variation of modern versions of the Michelson-Morley experiment (MMX) with one arm pointed in the vertical direction. ()  In 2003, Müller et al. performed a normal (2 horizontal orthogonal arms) modern MMX using cryogenic optical resonators that found a “possible anisotropy of the speed of light c, (of) 2.6 +/- 1.7 parts in 10^15” (  )  In a brief conversation with Holger Müller a Professor at Berkeley and the lead author of that paper, he stated that to this knowledge no one had ever performed a variation of the experiment using a vertical arm.  He also mentioned that such an experiment would be complicated by the fact that gravity would slightly compress the length of the vertical bar making two equal length bars no longer equal in length.  “They haven't been done as far as i know. The problem is that any interesting physics signal would be hard to tell from a large signal from stretching of the arms under their own weight.” - H. Müller  I am interested in attempting to run this experiment myself.  To that end, I have the following questions:   Given current Physics understanding, is there any reason to expect that such a vertical variation of the MMX wouldn’t return the exact same results as all other MMXs, namely that there is no anisotropy in the speed of light? Given the complications mentioned by Professor Müller, are there reasonable methods available to overcome them?  Especially considering the size of the effect (c + 11,187m/s vs c) is substantially larger than the accuracy obtained in his and similar modern MMXs. What is the order of magnitude cost of such an experiment?  If I am to fund this personally, would such a project cost \$10,000?  \$100,000? \$1,000,000? more?   Any insight offered on this topic will be greatly appreciated.  EDIT: For what its worth, for people looking at this years later.  As I originally alluded to in a comment to [WetSavannaAnimal aka Rod Vance]'s much appreciated and comprehensive answer.  While, I've become increasingly comfortable with the idea that there is a flow of aether or spacetime or whatever you want to call it into the Earth at 11km/s; I strongly believe that a vertical MMX would return the same null result as the horizontal one.  And I believe it will do so because of length contraction; that length contraction exactly masks any anisotropy of the speed of light by ensuring that the roundtrip time of light in any direction is a constant; that length contraction ensures Lorentz co-variance. How can i limit the character length in excerpt? Possible Duplicate:          I have a question after reading this post (). I like this function(Search Term Without Plugin) very much but the character length is too long. What php code should i add to make the excerpt shorter? Would appreciate if someone can suggest it. Thank you! I want to copy all images on my computer to a single folder How to install folding at home (Folding@home FAHControl) on Ubuntu 19.10 How to get rid of navigation symbols in beamer?