When should we remove pseudo-tags from a title?
Should questions include "tags" in their titles?
Is there any danger to letting food cook in a slow cooker for a very long time? I've recently started using a slow cooker and I was thinking about recipes that could be cooked for days.  My main concern is if there are any side effects for leaving food cooking for days that would make this plan unfeasible (dangerous to try).  Since it is at cooking temperature, there wouldn't be any reason to worry about bacteria growing on the food.  Liquid would be lost over time, which could result in burning if left unchecked, but if I add more every morning/night as needed, that too wouldn't be a problem.  All I can see is that most recipes wouldn't end up tasting as well, but undesirable isn't equal to dangerous.  There just seems to be something absurd with the notion of leaving food cooking for 5 days or even 2 weeks without there being any dangers, but I'm having a hard time figuring out what they would be. I have:  &lt;?php  $file=fopen(date("Y-m-d").".txt","r+") or exit("Unable to open file!");  if ($_POST["lastname"] &lt;&gt; "") {    fwrite($file,$_POST["lastname"]."\n"); }  fclose($file);  ?&gt;   but it overwrites the beginning of the file.  How do I make it insert? Can I use a card with "Add one mana of any color to your mana pool" in any Elder Dragon Highlander (EDH) deck? I recently tried /, and found it to be a ton of fun.  I've started customizing one of the pre-cons I got, but I'm a little confused by some of the deck-building requirements.  According to the deck-building rules:   A card's color identity is its color plus the color of any mana symbols in the card's rules text. A card's color identity is established before the game begins, and cannot be changed by game effects. Cards in a deck may not have any colors in their identity which are not shared with the commander of the deck. (The identity of each card in the deck must be a subset of the General's)    If I'm using  as my general, my deck's identity is Red, Blue and Green.  I couldn't use  in my deck, because it has a black mana symbol in the rules text.  My question is:  can I add a card to my deck that has the phrase "Add one mana of any color to your mana pool" (such as  or )?  Even though those cards could conceivably add black mana to my mana pool, they don't have a black or white (or any for that matter) mana symbol in their rules text, so they would be valid for inclusion in any deck? I'm a quarter Draconian, a quarter Dragonborn and half Half-Dragon? What are the differences between "Dragonborn", "Half-Dragon", and "Draconian" races in D&amp;D?  In the Hoard of the Dragon Queen adventure, for example there is  a Half-Dragon npc. I had assumed that when writing the adventure they were only allowed to use known material from Basic, and so renamed the Dragonborn into "Half-Dragon" for the sake of compatibility etc. However, the dragon breath rules are not at all similar for the half-dragon and the dragonborn, and I've also noticed wiki article that imply that they are different races entirely. (Thus introducing me to the term Draconian)  Are there clear differences between these three races, (in the same way there are differences between Goblins and Hobgoblins, or Dragonborn and Lizardfolk and Kobolds,) or are they really just three different setting names for the same basic race?  Answers can either be D&amp;D 5e specific, or be based on the lore from all editions of Dungeons and Dragons. (I'm assuming here that the answer will be the same regardless)  Here are two images, the first one is a "half-dragon" from the front of the Hoard of the Dragon queen module, and the second one is a "dragonborn" from the 5e player's Handbook.  I've included these images to help explain my confusion. It seems amongst is quite often used as a synonym for among but it is supposed to sound more distinguished. Is there any difference in the meaning? Multiple WHERE clause in Linq number of vertices in a self-complemntary graph Problem: Prove that the number of vertices of a self-complementary graph must be congruent to 0 or 1 modulo 4. I think my starting point would be that P4 and C5 are self-complementary and proceed by induction by adding P4s. I established the first step in a previous problem, but I need help on the induction step. i.e. proving that adjoining P4 will indeed yield a self-complementary graph. Reference to undeclared entity exception while working with XML I am trying to set the innerxml of a xmldoc but get the exception: Reference to undeclared entity  XmlDocument xmldoc = new XmlDocument(); string text = "Hello, I am text &amp;alpha; &amp;nbsp; &amp;ndash; &amp;mdash;" xmldoc.InnerXml = "&lt;p&gt;" + text + "&lt;/p&gt;";   This throws the exception:      Reference to undeclared entity 'alpha'. Line 2, position 2..    How would I go about solving this problem? How to make Arduino (Snap) access serial port /dev/ttyUSB0 (or /dev/ttyACM0)? I have Ubuntu 18.04 LTS installed.  I installed Arduino IDE v1.8.5 as a snap with  snap install arduino-mhall119   I have added my user to dial-out group and rebooted:  sudo usermod -a -G dialout $USER  $ groups  username adm dialout cdrom sudo dip plugdev lpadmin sambashare   I connected my Arduino Nano to the laptop, it is detected on port /dev/ttyUSB0 (ch341-uart).  $ ls /dev/ttyUSB0 -al crw-rw---- 1 root dialout 188, 0 авг 13 11:59 /dev/ttyUSB0   I tried to upload the simpliest Blink sketch and get the following errors in the terminal:  $ arduino-mhall119.arduino    avrdude: ser_open(): can't open device "/dev/ttyUSB0": Permission denied   Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.**   Also I have installed arduino 1.8.5 with umake - it can access serial port in usual way.  Note: we already have  here, but the solution was to use , not fix for the Snap.  So my question is: How to make Arduino (Snap) access serial port /dev/ttyUSB0 (or /dev/ttyACM0)?  Update: connecting serial-port to the snap fails with the following message  $ snap connect arduino-mhall119:serial-port  error: snap "core" has no "serial-port" interface slots   Current interfaces are:  $ snap interfaces | grep arduino :home                            arduino-mhall119,gedit,organize-my-files,vlc :network                         arduino-mhall119,gedit,organize-my-files,pulsemixer,vlc :unity7                          arduino-mhall119,gedit,organize-my-files,vlc :x11                             arduino-mhall119,organize-my-files,pulsemixer,vlc -                                arduino-mhall119:serial-port   Changing permissions of serial port to 777 with sudo chmod 777 /dev/ttyUSB0 does not help.  The following do not work too (because of syntax errors):  $ sudo snap connect arduino-mhall119:arduino error: snap "arduino-mhall119" has no plug named "arduino"  $ snap connect arduino-mhall119:/dev/ttyUSB0 error: snap "arduino-mhall119" has no plug named "/dev/ttyUSB0"  $ snap connect arduino-mhall119 error: cannot resolve connection, plug snap name is empty   Information about YAML-manifest:  $ ls -l /snap/arduino-mhall119/current/meta/snap.yaml -rw-r--r-- 1 root root 353 июл 28 00:20 /snap/arduino-mhall119/current/meta/snap.yaml  $ cat /snap/arduino-mhall119/current/meta/snap.yaml |grep -A 12 slots  $ cat /snap/arduino-mhall119/current/meta/snap.yaml |grep -A 5 plug     plugs:     - x11     - unity7     - home     - network     - serial-port Is there a general method (which can be implemented by hand) to finding the $n$-th roots of $2 \times 2$ matrices? Is there a similar method for a general $m \times m$ matrix? (for $n &gt; 1$ and $n\in\mathbb{Z}$) Please use UK pre-uni methods only (at least at first). Thank you. I currently have a setup where I send a char using a Tx of 434MHz and an Uno to a Mega with a Rx. The Mega counts how many times it receives the char and then if it falls below a certain number it triggers an alarm. Is this a viable way to measure the distance between two microcontrollers while indoors or is there a better way.  Transmitter (Mega)  #include &lt;SoftwareSerial.h&gt;  int rxPin=2; //Goes to the Receiver Pin int txPin=5; //Make sure it is set to pin 5 going to input of receiver  SoftwareSerial txSerial = SoftwareSerial(rxPin, txPin); SoftwareSerial rxSerial = SoftwareSerial(txPin, rxPin); char sendChar ='H';  void setup() {   pinMode(rxPin, INPUT);   pinMode(txPin,OUTPUT);   txSerial.begin(2400);   rxSerial.begin(2400); }  void loop() {   txSerial.println(sendChar);   Serial.print(sendChar); }   Receiver  #include &lt;SoftwareSerial.h&gt;  //Make sure it is set to pin 5 going to the data input of the transmitter int rxPin=5;  int txPin=3; //Don't need to make connections int LED=13; int BUZZ=9; int t=0;  char incomingChar = 0; int counter = 0;  SoftwareSerial rxSerial = SoftwareSerial(rxPin, txPin);  void setup() {   pinMode(rxPin, INPUT); //initilize rxpin as input   pinMode(BUZZ, OUTPUT); //initilize buzz for output   pinMode(LED, OUTPUT); //initilize led for output   rxSerial.begin(2400); //set baud rate for transmission   Serial.begin(2400); //see above }  void loop() {   for(int i=0; i&lt;200; i++) {     incomingChar = rxSerial.read(); //read incoming msg from tx      if (incomingChar =='H') {       counter++; //if we get bit "h" count it       }     delay(5); //delay of 10 secs   }   Serial.println(incomingChar);   Serial.println(counter); //prints the the bits we recieved    if(counter&lt;55) {     //if we receive less than 100 bits than print out of range triggers alarm     Serial.println("out of range");      tone(BUZZ,5000,500);digitalWrite(LED,HIGH);   }   else {     noTone(BUZZ);digitalWrite(LED, LOW);     //if we get more than 100 bits than we are within range turn off alarm     Serial.println("in range");    }    counter = 0;   incomingChar=0; } Prove that for $ 0&lt;x&lt; \pi $, $$ \quad S_n(x) = \sin x + \frac{ \sin3x }{3} + ... + \frac{ \sin((2n-1)x) }{2n-1} &gt;0 \quad \forall n = 1,2,... $$  Having trouble with this problem. This is an olympiad-style question, so an answer that doesn't use calculus or analysis would be preferred. A possible approach is induction, but for this we need to find a function in terms of $n$ and $x$ so that we can actually use the inductive step. If anyone has any ideas they would be appreciated.  If you really want to go down the calculus route (at this point I don't mind), then $ S_n' (x) = \cos x + \cos 3x + ... +\cos((2n-1)x) $ , which you can find a closed form for, but I don't know how useful that is. How do I create a D&D character correctly as a total newbie? When should I not kill -9 a process? Is there a way to check if a file is checked out by another user? I am going trhough a list file by file and would like to avoid the "file is opened by another user" error. Something like this would be nice:  Guid id = new Guid(slideLibrary); // ID of Slide-Library. List list = ctx.Web.Lists.GetById(id); ListItemCollection items = list.GetItems(CamlQuery.CreateAllItemsQuery()); ctx.Load(items); // Loading all the fields System.Security.SecureString pwd = new System.Security.SecureString(); foreach (char c in "pwd".ToCharArray()) pwd.AppendChar(c);  ctx.Credentials = new SharePointOnlineCredentials(login, pwd); ctx.ExecuteQuery();  // Iterating through all the entries. foreach (var item in items) {     String currentID = item["ID"].ToString(); // Getting the ID of the current item.      if (!item.IsCheckedOut()) // This is the part I am looking for.     {        // Do stuff     }     else     {        Console.WriteLine("Item is blocked, skipping it.")     } }   I have yet not been able to find something fitting. gdal.VectorTranslate returns an empty file Is there a way to capture the viewport in Blender the same way as it is on 3DS Max? I know that by default I can render the viewport and everithing that is in the viewport to be the same as in the render. But, when comparing 3DS Max to Blender, I have certain limitations. In Blender I can render the view-port with vertices/edges/faces to be shown, to be selected, but not the reflections, shadows and such.  Is there a way to render the viewport in Blender as it is in 3DS Max?  Here's how I can do it in 3DS Max:  Viewport look    Render result of the viewport    Here is how I can do it in Blender:  Viewport look:      Render result of the viewport How are classical optics phenomena explained in QED (Snell's law)? How is the following classical optics phenomenon explained in quantum electrodynamics?   Reflection and Refraction   Are they simply due to photons being absorbed and re-emitted? How do we get to Snell's law, for example, in that case?  Split by request: See the other part of this question . Cohen's d for 2x2 interaction I have a significant 2x2 interaction in a between-subjects design.  I would normally report omega-squared as my effect-size measure, but I've been asked to provide Cohen's d instead?  Can Cohen's d be computed for an interaction?  If so, how?