Get a truly RANDOM row from a PostgreSQL table quickly
Is "TABLESAMPLE BERNOULLI(1)" not very random at all?
We have $q, p$ prime and $tq = (p-1)(p+1)$ for some positive integer $t$. The book I'm reading says that because $q$ is prime, it divides $p-1$ or $p+1$.   Question: Why exactly does it matter that $q$ is prime here? Can I apply multiple background colors with CSS3? Need help in the longtable with the figure Can u please help me in this table. The problem in this table that is not move to the next page in a proper way and kindly mention the size of the figure as well as the place of the figure. \begin{longtable}[c]{@{}|c|c|c|c|c|c|c|c|c|@{}} \caption{Bacteria isolates on different media} \label{tab:my-table}\\ \toprule \textbf{Sr.No} &amp;   \textbf{Reference Code} &amp;   \textbf{Sample Location} &amp;   \textbf{Colony Color} &amp;   \textbf{Colony Morphology} &amp;   \textbf{Pigmentation} &amp;   \textbf{Media} &amp;   \textbf{Predicted Name Of Strain} &amp;   \textbf{Figures} \\* \midrule \endhead % 1 &amp;   EMB(P)1 &amp;   Islamabad &amp;   Green sheen &amp;   Circular &amp;   Green Sheen &amp;   \begin{tabular}[c]{@{}c@{}}Eosin methylene\\    \\ blue agar\end{tabular} &amp;   \textit{\textbf{E.coil}} &amp;    \\* \midrule 2 &amp;   MSA(P)1 &amp;   Islamabad &amp;   Yellow &amp;   Punctiform &amp;   Yellow &amp;   Mannitol salt agar &amp;   \textit{\textbf{\begin{tabular}[c]{@{}c@{}}Staphylococcus\\    \\ Epidermidis\end{tabular}}} &amp;    \\* \midrule 3  &amp; MACC(P)1 &amp; Islamabad &amp; Off white       &amp; Circular  &amp; Off white       &amp; MacConkey agar     &amp; \textit{\textbf{Salmonella}}              &amp;  \\* \midrule 4  &amp; MSA(P)2  &amp; Islamabad &amp; White           &amp; Circular  &amp; White           &amp; Mannitol salt agar &amp; \textit{\textbf{Staphylococcus   aureus}} &amp;  \\* \midrule 5 &amp;   B.A(P)1 &amp;   Islamabad &amp;   White &amp;   Smooth &amp;   White &amp;   \begin{tabular}[c]{@{}c@{}}Blood \\    \\ Agar\end{tabular} &amp;   \textit{\textbf{Pseudomonas   aeruginosa}} &amp;    \\* \midrule 6  &amp; B.A(P)2  &amp; Islamabad &amp; White           &amp; Circular  &amp; White           &amp; Blood agar         &amp; \textit{\textbf{Lactobacilli}}            &amp;  \\* \midrule 7  &amp; MACC(P)2 &amp; Islamabad &amp; Pink            &amp; Circular  &amp; Pink            &amp; MacConkey agar     &amp; \textit{\textbf{Klebsiella}}              &amp;  \\* \midrule 8  &amp; MACC(P)3 &amp; Islamabad &amp; Purple          &amp; Irregular &amp; Purple          &amp; MacConkey agar     &amp; \textit{\textbf{pseudomonas}}             &amp;  \\* \midrule 9  &amp; MSA(P)3  &amp; Islamabad &amp; Crystal White   &amp; spherical &amp; Crystal White   &amp; Mannitol salt agar &amp; \textit{\textbf{Salmonella}}              &amp;  \\* \midrule 10 &amp; B.A(P)3  &amp; Islamabad &amp; White           &amp; Puntiform &amp; White           &amp; Blood agar         &amp; \textit{\textbf{Staphylococcus}}          &amp;  \\* \midrule 11 &amp; MACC(P)4 &amp; Islamabad &amp; Orange to amber &amp; Circular  &amp; Orange to amber &amp; MacConkey agar     &amp; \textit{\textbf{Shigella}}                &amp;  \\* \midrule 12 &amp; MSA(P)4  &amp; Islamabad &amp; Yellow          &amp; Circular  &amp; Yellow          &amp; Mannitol salt agar &amp; \textit{\textbf{S. aureus}}               &amp;  \\* \midrule 13 &amp; MACC(P)5 &amp; Islamabad &amp; Pink to purple  &amp; Circular  &amp; Pink to purple  &amp; MacConkey          &amp; \textit{\textbf{Klebisella}}              &amp;  \\* \bottomrule \end{longtable} When cutting/copying some cells to paste them into another sheet/page, sometimes Excel freezes/locks up and fades out. At the top toolbar it says in brackets "not responding".  Eventually, I must click 'X' to close the program. It offers to wait for the program to respond, but never does – it just does nothing until I finally close it, where it offers to recover files etc.   Is there an issue with memory here? What can I do to stop it locking up? Implicit Differentiation Help I have to use implicit differentiation to find $\frac{dy}{dx}$ given:  $$x^2 \cos(y) + \sin(2y) = xy$$  I don't even know where to begin, I missed the class where we went over implicit differentiation, and because of that, I am completely stuck.   Thank you everyone.  Edit: I don't know how to make the equation look all nice and whatnot, so sorry about that If apostrophe + s is the acceptable way of denoting a genitive in English, is it possible that possessive pronouns, such as hers, ours and yours, started life as possessive adjectives with apostrophe + s?  E.g. her's, our's, your's, their's? Perhaps, even his' ? Its and my obviously stick out from this tempting pattern.  Is there any evidence that this might be the case, or is the 's completely unrelated? How do you check the windows version in Win32 at runtime? How do you check the windows version in Win32 at runtime? My refrigerator line is 20 amp with 12 gauge wire. Can I tap into that with 14/2 wire, and run a light switch and 1 LED light? Create WiFi hotspot with web access point I want to setup a WiFi network with access through a web interface. Essentially people would be asked to enter a username/password and their session would be valid for X minutes after which they'd be logged out.  I am capable of quite a few programming/scripting languages, but browsing through router settings I don't see how to/where hosted/etc. the web interface/session handling comes in.  Please push me the right direction. Story about building up speed leading to increased quality of life We're all familair with this beautiful proof whether or not an irrational number to an irrational power can be rational. It goes something like this:  Take $(\sqrt{2})^{\sqrt{2}}$  If it's rational, then you proved it, if it's irrational, take $((\sqrt{2})^{\sqrt{2}} ){^\sqrt{2}} = 2$ and you've proved it.  I'm wondering if you can raise $\pi$ or $e$ to a certain non-trivial real power to make it rational? And if not, where is the proof that it can't be done?   p.s. - I almost left out the real part, but then I realized that $e^{i\pi} = -1$. Dual boot Win 10 + Ubuntu SSD+HDD first of all thank you for answering.  I have a 120GB SSD and a 1TB HDD and I want to dual boot with Windows 10. I tried with this configuration:  SSD  / (ext4 20GB) /usr (ext4 15GB) /boot/efi (ext4 250MB)  HDD  /var (ext4 3GB) /tmp (ext4 8GB) /home (ext4 50GB) swap (none 24GB) (RAM 16GB)  I don't know if I am doing OK, as I tried to install it but installation gets stuck at "Saving installed packages..." and it doesn't continue. I wonder if it could be cause I didn't  partitioned as I had to. I don't find any post where this happens so I ask here.  Thanks! When a land becomes creature, can you kill it? Some lands have an ability to become a creature, but they usually say they are still a land. If a land is a 3/3 creature and a land, can you target and kill it with a  to send it to the graveyard, or does it remain in play as a land? I'm training a neural network but the training loss doesn't decrease. How can I fix this?  I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set.    This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion:   If your neural network does not generalize well, see: I got a flat/puncture on my bike tube, how can I fix it myself without going to the nearest bike shop? What kind of equipment would I need? Extruding surface while keeping the shape here is the picture of what I would like to get(example nr. 2). I need the edge frame to be same in width and length. Also the extrusion is on surface (without depth) I tried extruding region, but it did not give me the result I wanted.   I know I could just adjust the scale and do it manually, but that would be eyeballing without achievign accuracy. I would like to know if it is possible to extrude or inset while keeping the shape (even edge space) Parallel execution of bash script I have a table URL_Experiment in my database (mySQL database). I have 2 million URL links in this table.  For each URL, I am checking if some particular text is present in the URL and updating the information back in my URL_Experiment table.    Now, I need to make the script run fast. The easy solution that comes to my mind is:  split the URL_Experiment into 10 tables (each with 200,000 rows) and run the script 10 times simultaneously. This way, I can ensure that the updates happen properly. But for this, I need to save 10 scripts, each accessing the correct table (I need to rename the tables from 1 to 10).   Though the above seems a pretty neat solution, I am looking for a more sophisticated solution. Something which will execute the same script simultaneously (in parallel) as 10 processes. My concern is the execution time. I do not want the resources to be wasted when they can be utilized. Change \textwidth after first page in scrlttr2 Is there any way to bring an egg to its natural state (not boiled) after you cook it? This is probably a stupid question, but I'm curious now after I opened the refrigerator looking for eggs to make a cake and there was only one and it was cooked. Is there any way to undo that, whether at home or an industrial way? How can I calculate the angle and proper turn direction between two 2D vectors?