Is this a subject-verb agreement error?
"The news is good." Why?
Give a combinatorial proof: $ n(n+1)2^{n-2} = \sum_{k=1}^{n}k^2\binom{n}{k} $ Find a combinatorial argument for the following binomial identity:   $$n(n+1)2^{n-2} = \sum_{k=1}^{n}k^2\binom{n}{k} .$$   Algebraic proofs can be found at  , and a related identity at  . SQL Server - how to determine if indexes aren't being used? Which is faster/best? SELECT * or SELECT column1, colum2, column3, etc I've heard that SELECT * is generally bad practice to use when writing SQL commands because it is more efficient to SELECT columns you specifically need.  If I need to SELECT every column in a table, should I use   SELECT * FROM TABLE   or   SELECT column1, colum2, column3, etc. FROM TABLE   Does the efficiency really matter in this case? I'd think SELECT * would be more optimal internally if you really need all of the data, but I'm saying this with no real understanding of database.  I'm curious to know what the best practice is in this case.  UPDATE: I probably should specify that the only situation where I would really want to do a SELECT * is when I'm selecting data from one table where I know all columns will always need to be retrieved, even when new columns are added.   Given the responses I've seen however, this still seems like a bad idea and SELECT * should never be used for a lot more technical reasons that I ever though about. How do I remove the limit on PC keyboard button presses? What should be the default title case for non-technical questions? As an example, this question is titled using sentence case. I've been going to lots of different meta sites (especially this one), and I think the needle bent on my oh-me-oh-my-my-ocd-oh-meter.  Can we please standardize on using either:   Sentence case Title Case AP Style Title Case   ... and then we can look at just converting titles automatically? This would be a switch, of course, but I'd only imagine turning it off on sites where program code or symbols might be present in titles. Or, it could just become part of editing guidelines.    Additionally, is this a horrible idea?   To see the differences between them, you can put any arbitrary title into  (we have no affiliation with them, it's just a tool I sometimes recommend to people).  We would also eventually adopt this for static routes, but I'm mostly talking about questions. Can the Earth's magnetic field be used to generate electricity? wp_delete_auto_drafts() deletes links in menus Since yesterday the wp_scheduled_auto_draft_delete cron job somehow deletes all page entries from our menus. All entries in the table wp_postmeta with meta_key = '_menu_item_object' and meta_value = 'page' get deleted in the process. By tracing back the DELETE query I found out that the menu entries are deleted by a function called _wp_delete_post_menu_item. I got the following stacktrace for that function:  #0  _wp_delete_post_menu_item(3244) #1  call_user_func_array(_wp_delete_post_menu_item, Array ([0] =&gt; 3244)) called at [/srv/www/htdocs/biva/wp-includes/plugin.php:470] #2  do_action(delete_post, 3244) called at [/srv/www/htdocs/biva/wp-includes/post.php:2483] #3  wp_delete_post(3244, 1) called at [/srv/www/htdocs/biva/wp-includes/post.php:5645] #4  wp_delete_auto_drafts() #5  call_user_func_array(wp_delete_auto_drafts, Array ()) called at [/srv/www/htdocs/biva/wp-includes/plugin.php:546] #6  do_action_ref_array(wp_scheduled_auto_draft_delete, Array ()) called at [/srv/www/htdocs/biva/wp-cron.php:100]   But I'm stuck here, I'm not a wordpress developer and I have no clue why deleting old drafts results in deleting attached menu entries although the main pages still exist.  Workaround: As a workaround we added the following to the top of wp-config, wich will disable wp-cron:  /** Disable wp-cron to prevent menu from getting deleted. Detailed Bug description: http://wordpress.stackexchange.com/questions/145953 **/ define('DISABLE_WP_CRON', true);   If you are experiencing similar difficulties you might try locking the rows in the table wp_postmeta with meta_key = '_menu_item_object' and meta_value = 'page' and then tracing back the error message when WP trys to delete these rows, that's how we nailed down our error.  Reproduce the Error: It is definitely the stealth publish plugin that is causing our error, one can easily reproduce it, by doing the following:   Install a fresh Wordpress 3.9.1. Install the stealth publish plugin . Create a few test pages and add them to a new menu. Create a new page, with some dummy content, but do not save it!. Leave the page without saving. Change the system time 8 days into the future. The wp_scheduled_auto_draft_delete cron job will run because it runs daily and it hasn't run for 7 days as soon as you visit your page. It will then find your never saved dummy page delete it as it is older than 7 days and the menu will vanish. You might need to refresh the page a few times till the effect becomes visible.   I've recorded a screencast on how to reproduce the error (but I took not the time to comment it): How do I make my screenshot ask me what to do next every time? I take screenshots a lot. I usually take screenshot of an area, I then recheck if I have the desired area and then copy it to clipboard.  I want to change this behaviour so that immediately upon  pressing Shift+PrntScr the screen capture application allows me to select an area, and immediately afterwards it provides me with the option to save to a particular location or clipboard.  I want Shift+PrntScr to bring up a pop-up screen like this: Did I correctly derive this recurrence equation formula What is the best way to put a backdoor in an encryption system? How can you put a backdoor into an encryption algorithm? Are there any techniques that can be used to reduce the time it takes to break a key?  I am looking for practical examples encryption schemes that have backdoors, because they were designed to or new techniques exposed them. It is my understanding that you can use a lack of entropy and diffusion in block ciphers which will reduce the necessary time that it takes to break a key. This is especially true with s-boxes, which can be designed to not increase the strength of the key. As for one-way algorithms, using none-primes can make it easier to reverse keys. What are other decisions that can be made to make a broken encryption algorithm?   The goal is find examples that can be used for encryption pedagogy, by collecting a sample of weak ciphers to practice on. Why is the Principle of Superposition true in EM? Does it hold more generally? In the theory of electromagnetism (EM), why is the principle of superposition true? Can we read it off from Maxwell's equations directly?  Does it have any limit of applicability or is it a fundamental property of nature? How to install a QGIS plugin when offline? Due to various IT policies at my workplace, QGIS is installed on a machine that is not connected to the internet. I wish to install a couple of QGIS plugins on this system.  I have downloaded the required plugins from . How do I install them in QGIS? Why can't variables be declared in a switch statement? How exactly does a  work?  This is an extremely broad question. What code keeps things bouncing against each other, what code makes the player walk into a wall instead of walk through the wall? How does the code constantly refresh the players position and objects position to keep gravity and collision working as it should?  If you don't know what a collision engine is, basically it's generally used in  to make the player acutally hit walls and the like. There's the 2D type and the 3D type, but they all accomplish the same thing: collision.  So, what keeps a collision engine ticking? The default font is too small on my screen at the resolution I have it, so I like to reset the font to size 12, but it appears I have to do this everytime I launch the program.  How do I make it remember my preferences? Why do you lose reputation for downvoting answers? Typeerror: object.__new__() takes no parameters (help) How to run "sudo apt-get update" through proxy in commandline? In my office i want to update and download through (wget) and here they are using proxy?  How can i do this by commandline? What happens with lethargy when Haste is cast again on a creature before first cast runs out? What are the regulations for transporting medication abroad? This is in reference to medications, both prescription and non-prescription, not illicit drugs. Since the legality may vary on country, let's say a round trip from the US to Singapore, as an example.  When travelling with prescription medication, I am aware that you are supposed to bring your prescription with you. What about over-the-counter medication, such as Tylenol/aspirin? How about medication which is restricted or prescription-only in one country, yet available OTC in another (think Viagra)?