Till what grade, till grade
Asking the position of a person in a sequence
Union of two vector subspaces not a subspace? Equivalence principle question I understand the  as "The physics in a freely-falling small laboratory is that of special relativity (SR)." But I'm not quite sure why this is equivalent to "One cannot tell whether a laboratory on Earth is not actually in a rocket accelerating at 1 g". How can I reinstall GRUB to the EFI partition? Why does Sass change the format of my colors? I'm trying to use itemize inside a tabularx environment, but I have a problem when I mention the end of the line. It seems that using \\ end the line after the end of itemize, resulting in a supplementary vertical spacing that I would like to remove.  Any hint?  \begin{frame} \frametitle{Sujet de thèse}         \begin{center}             \textit{Sujet N$^\circ$221 : Formation et dynamique des champs de dunes longitudinales.}         \end{center}          \begin{tabularx}{\textwidth}{l !{\color{blue}\vline width 3pt} X}             Contexte &amp;  \scriptsize{Classification des dunes selon leur mécanisme de croissance, leur orientation et leur forme.              Bonne compréhension :             \begin{itemize}[noitemsep,topsep=0pt, label=\textbullet]                 \item du mécanisme de croissance lié à une disponibilité en sédiment grande.                 \item de la croissance sous un vent unidirectionnel.             \end{itemize}} \\             Objectifs &amp; \scriptsize{Etude de l'orientation longitudinale :             \begin{itemize}[noitemsep,topsep=0pt, label=\textbullet, parsep=0pt ]                 \setlength\itemsep{0cm}                 \item Développement d'un formalisme sous des vents multidirectionnels.                 \item Etude des dunes longitudinales dans le cas d'une faible disponibilité en sédiment. (Fingering mode)                 \item Inversion: données topographiques $\longrightarrow$ Données de vents $\rightarrow$ paléo-climats.              \end{itemize}} \\             Outils &amp; \scriptsize{Modèle numérique (Rescal), Données expérimentales, Théorie.} \\         \end{tabularx}     \end{frame}     And yes, dunno if it's important but everything is inside beamer. decode a quoted printable message in php I have the string which that encoded in .  How do I decode this in php?  Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Vestibulum felis = pede, vestibulum et, ullamcorper in, ultrices eget, metus. Suspendisse in n= ulla. Sed justo. Donec dapibus auctor neque. Pellentesque faucibus ante nec=  metus. Vivamus feugiat, velit rhoncus semper suscipit, libero augue venena= tis leo, nec ornare nulla elit eget diam. Nullam sollicitudin. Are partitions to the inner/outer edge significantly faster Some linux dual/multi-boot tutorials / general partitioning tutorials say that the inner side of a hard disk is faster than the outer side so partitions towards the outside tend to be slower while some say that the exact opposite is true.  Which side is actually faster?  Is the difference noticeable?  How are the partitions physically placed on the disk as compared to the partition listing order-for example gparted shows a logical ribbon layout of the partitions. Are the partitions shown to the left side of this ribbon near the outer or inner edge of the disk physically?  Are there software benchmarks like testing some disk intensive stuff for the first time on identical vanilla installs of the same OS but on different partitions, inner and outer?  EDIT: Links   ctrl + f for "slower" on this page   Says outer side is faster   Says inner side is faster   Says outer side is faster(not about dual-booting) I am trying to create an spritz app. Everything was working fine, but since yesterday I keep getting this error:     ./spritz: line 176: syntax error: unexpected end of file   I have checked the script file and everything seems perfect. I am confused, I have an if statement at last and it looks correct! Here is the last portion:  #checks if speed is 150 157 if [[ $2 -eq 150 ]]; 158 then 159 starttime=$SECONDS 160      FS=$'\n' 161      for j in `grep --color=always -iP '\b[^aeiou\s]*[aeiou][^aeiou\s]*\K[aeiou]' $1`; 162      do 163            #Reads the text file in the centre of the screen 164            echo "                                                    ___________________" 165            echo "                                                             $j"; 166            echo "                                                    ___________________" 167            echo "                                                                               Speed 150 wpm" 168            sleep  0.9; 169            clear; 170       done 171 endtime=$(($SECONDS - $starttime)) 172            echo "You read $words_read words in $endtime seconds!" 173       exit 8 174 fi   What could cause that error? General term of Taylor Series of $\sin x$ centered at $\pi/4$ Vertically align text next to an image? Italian keyboard: entering tilde (~) and backtick (`) characters without changing keyboard layout Are universal power supplies for laptops worth it? My laptop's cable broke and sadly it seems like I need to buy a new power supply.  What I wonder is, I've found that universal power supplies are much cheaper than the official HP ones. Are they really worth it?  Another question: the original supply has these specs: 65W, 18.5V, 3.5A. However the universal supplies are more powerful (90W, 100W) and come in integer voltages (17V, 18V, 19V, etc). Are they compatible? Should I set them to 18V or 19V? In Ubuntu, I want to scroll up while a command is running in my terminal window and generates new output (the command that is running is rspec). I can scroll up, but each time rspec generates a new line of console output, it throws me back down to the bottom. Is there a way to scroll all the way up? I'm using terminator on Linux Mint/Ubuntu 12.04 LTS. I found a possible workaround.  says that with stty ixon  you can turn on &quot;XON/XOFF flow control for terminal output. Being able to pause output by typing ^S and resume it by typing ^Q [...]&quot; This it not totally what I wanted though, without having to pause the output (and maybe wondering when forgetting to turn it on again), I thought there might be a simple modifier key like shft-alt with mouse wheel scroll-up. Are there better solutions? What is the metal sheath surrounding a USB connector, and is it commonly connected? ,  and 1 still show the old bar. 1 See How can I dual boot Windows and Ubuntu? I currently have Windows 7 on my computer and I want to install Ubuntu alongside Windows safely.  Could someone please provide clear instructions? I am trying to install Ubuntu 16.04 LTS on a Dell XPS 13 (9350). The laptop came with Windows 10 pre-installed. I am installing from a pendrive but I think the issue would be the same if I used e.g. a USB DVD drive.   Dude, where's my hard drive?  I am blocked because the installation program cannot find 8.6Gb of free space on my hard drive despite the fact that there are hundreds of Gb free according to Windows. Digging a bit into the problem, it seems that Ubuntu cannot see my hard disk at all.    This is the output of GParted:    I am not sure what that drive mounted at /cdrom is, but it seems the only device that exists in the system that is not a RAM disk or a loop device:   Content of /proc/partitions:   ubuntu@ubuntu:~$ cat /proc/partitions   major minor  #blocks  name     1        0      65536 ram0     1        1      65536 ram1     1        2      65536 ram2     1        3      65536 ram3     1        4      65536 ram4     1        5      65536 ram5     1        6      65536 ram6     1        7      65536 ram7     1        8      65536 ram8     1        9      65536 ram9     1       10      65536 ram10     1       11      65536 ram11     1       12      65536 ram12     1       13      65536 ram13     1       14      65536 ram14     1       15      65536 ram15     7        0     130048 loop0     7        1    1104188 loop1     8        0    1970239 sda     8        1    1953439 sda1   Summary of fdisk -l:   ubuntu@ubuntu:~$ sudo fdisk -l |grep Disk Disk /dev/ram0: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram1: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram2: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram3: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram4: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram5: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram6: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram7: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram8: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram9: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram10: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram11: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram12: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram13: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram14: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/ram15: 64 MiB, 67108864 bytes, 131072 sectors Disk /dev/loop0: 127 MiB, 133169152 bytes, 260096 sectors Disk /dev/loop1: 1.1 GiB, 1130688512 bytes, 2208376 sectors Disk /dev/sda: 1.9 GiB, 2017525248 bytes, 3940479 sectors Disklabel type: dos Disk identifier: 0x00000000   Result of fdisk of the only non-loop non-RAM device (not sure this is relevant):   ubuntu@ubuntu:~$ sudo fdisk -l |grep -A 50 sda Disk /dev/sda: 1.9 GiB, 2017525248 bytes, 3940479 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x00000000  Device     Boot Start     End Sectors  Size Id Type /dev/sda1  *      129 3907007 3906879  1.9G  c W95 FAT32 (LBA)   I am blocked at this point. Any help will be much appreciated.   Additional information (following comments):   Running dmesg |grep -i sata shows (among others) eight lines that suggest some kind of error:   ata1: SATA link down (SStatus FFFFFFFF SControl FFFFFFFF) ata2: SATA link down (SStatus FFFFFFFF SControl FFFFFFFF) ata3: SATA link down (SStatus FFFFFFFF SControl FFFFFFFF) ata4: SATA link down (SStatus 0 SControl 0) ata5: SATA link down (SStatus 0 SControl 0) ata6: SATA link down (SStatus 0 SControl 0) ata7: SATA link down (SStatus 0 SControl 0) ata8: SATA link down (SStatus 0 SControl 0)  I have "Restarted" windows instead of only "Shutdown" it to avoid problems with "fast startup", following some recommendations I have read of other users having problems installing Linux on Windows 10 laptops.ago   Regarding SATA, the BIOS says: "SATA Operation: RAID ON". The other two options available are "Disabled" and "AHCI".    I have followed the instructions of these two pages from Dell: , . How to do a generalized linear model with multiple dependent variables in R? How do I use itertools.groupby()? I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function.  What I'm trying to do is this:  Take a list - in this case, the children of an objectified lxml element Divide it into groups based on some criteria Then later iterate over each of these groups separately.  I've reviewed , but I've had trouble trying to apply them beyond a simple list of numbers. So, how do I use of itertools.groupby()?  Is there another technique I should be using?  Pointers to good &quot;prerequisite&quot; reading would also be appreciated. Someone recently asked me why a negative $\times$ a negative is positive, and why a negative $\times$ a positive is negative, etc.  I went ahead and gave them a proof by contradiction like so:  Assume $(-x) \cdot (-y) = -xy$  Then divide both sides by $(-x)$ and you get $(-y) = y$  Since we have a contradiction, then our first assumption must be incorrect.  I'm guessing I did something wrong here. Since the conclusion of $(-x) \cdot (-y) = (xy)$ is hard to derive from what I wrote.  Is there a better way to explain this?  Is my proof incorrect?  Also, what would be an intuitive way to explain the negation concept, if there is one?