I need to be able to receive emails from my php webform on my website, I use Google Apps for the mail recipient and my website is hosted with Godaddy. I receive email from other places and I have looked and I think the problem is that the web sever thinks they are 'local' messages. In addition to this I also want to allow a site called bookerville to send messages from my site on my behalf. They provided me with the follow SPF code...  v=spf1 include:bookerville.com ?all   Some one set up the current SPF record which seems to be invalid which is (i don't think the ip4 bit is correct as I beleive it needs the sever ip address after it? Also I read on another thread that the ip4 bit isn't required???:  v=spf1 mx ip4:v=spf1 include:bookerville.com ?all include:secureserver.net ~all   I had a look around the web and on here and this seems to be the closest solution although I don't know much about Mx and SPF records so feeling out of my depth.  v=spf1 include:_spf.google.com a a:abc.example.org a:xyz.example.org -all   . This says, include Google's SPF record (which will allow all their mail servers to send mail on behalf of your domain), and allow anything in this domain which has an A record, and specifically allow 2 other hosts by verifying their A records. Fail everything else.    Lets say my website is www.example.com. Can someone provide me with a suitable SPF text to include the bookerville code (ABOVE) and also any code required for google and which will allow for php form mail to come through??  Thanks in advance


Cannot retract downvote if post has been edited within first 5 minutes of posting

Please do not close this as a duplicate unless you can remove the “status-completed” tag from the  (because it’s obviously not been completed).  Steps to reproduce:   Have someone post an answer. Downvote the answer. Have the someone edit the answer within the initial 5 minutes of the answer’s existence. Try to undo the downvote more than 10 minutes later.   You cannot undo the downvote.


How do the definitions of "irreducible" and "prime" elements differ?

In my commutative algebra lecture notes it says:  A non-zero element $p$ of a ring $R$ which is not a unit of $R$ is called a prime element if $p=ab$ implies $a$ is a unit or $b$ is a unit.  Is this not the definition of an irreducible element?? Everywhere else I've read that a non-zero, non-unit element $p$ is a prime element if $p|ab $ implies $p|a$ or $p|b$  Thanks :)


So I am just making a little blog project with codeigniter. What I am trying to do is once a comment is added, I want to be able to delete it. Deleting comments works for older comments, but not for the newer ones added. In order for them to be deleted the page has to be refreshed. I have looked through some answers on stackoverflow already but none seem to be my problem. The problem is when I click remove on my new comment, its not registering that I have even clicked the element. If you look below I added a console.log test which should show up when I click the element, but nothing happens. How would I fix this?  EDIT: I noticed something in the console (Using firefox). Near to the remove element there is a black little box with "ev" written in it. It comes up next to the other comments but not the new comment.  EDIT: Ok I should have done a little more digging, I found the answer:  Change   $(".com-delete").click(function()   TO   $(document).on("click",".com-delete",function()   Code:


Transforming EC public key X and Y-sign into X and Y

I'm using bouncycastle which uses X and Y coordinates for public keys.  An EC public key is more compactly represented by the X coordinate and the sign of the Y coordinate.  How do I use bouncycastle to transform X and Y into X and Y-sign, and vice versa. (The curve is secp256k1 if that makes any difference.)


iMessage and FaceTime not working with Apple ID any more

My iMessage and FaceTime suddenly stopped working with my Apple ID on my Macbook Pro (OS X 10.9.5) during my vacation at NYC.  Even on my iPhone (iOS 10.3.3) I can now only use iMessage and FaceTime with my phone number, but not with my Apple ID independent from my location.  Everytime I try to activate iMessage and FaceTime on my MacBook and my iPhone following error is shown:     An error occurred during activation   I've checked my Date & Time settings and the current location to be true, reset NVRAM and checked all my settings, but there is no solution in sight. I also deleted my Apple ID accounts from all my Apple devices and reconnected them after a reboot of each device, like recommended by Apple and several other webpages.  Does anyone know a possible solution, or has similar problems?  I don't want to update my Mac or iPhone. The solutions provided to the question  suggesting to clear NVRAM and to delete the keychain don't work for me, and iMessage and FaceTime do work but only with my phone number.


The Solutions $(a,b,c,d)$ of $a^0+a^1+a^2+\cdots+a^{b-1}+a^b=c^d$

Let $a\ge2, b\ge2,c\ge2,d\ge2\in\mathbb N$. Also, let $N(a,b,c,d)$ be the number of the solutions $(a,b,c,d)$ of $$a^0+a^1+a^2+\cdots+a^{b-1}+a^b=c^d.$$ Then, here is my question.  Question : Are the followings true? $(1)$  $N(a,b,c,2)=2$. $(2)$ $N(a,b,c,3)=1$. $(3)$ There exist $d$ such that $N(a,b,c,d)=0$. $(4)$ For every $d\ge2$, $N(a,b,c,d)$ is finite.  Example : $${3}^{0}+{3}^1+{3}^2+3^3+3^4={11}^2,$$ $${7}^{0}+{7}^1+{7}^2+7^3={20}^2,$$ $${18}^{0}+{18}^1+{18}^2=7^3.$$ Motivation : I have not been able to find the other solutions even by using computer (I hope I don't miss anything). I don't have any good idea for answering these questions. I would like to know any relevant references. Can anyone help?


Am I allowed to bring a drone to Kansai, Japan?

I'm going to Japan and planning to bring a drone with me. However, I'm worried that my drone is going to be confiscated at the airport.   Are there any rules for bringing a drone into Kansai, Japan?


I have a a form where a user can make a simple multiplication of two fields. The outcome of the equation is then placed in another input field using jquery.  quantity =         Number($('#quantity').val()); price =            Number($('#price').val());  subtotal = quantity * price;   and  $("input#subtotal").val(subtotal);    But...The numbers do not add up!!   I'm getting very strange answers with long decimals behind the comma. When running my console:  console.log(subtotal, price+ "x" + quantity + "=" + subtotal);       it literally states:  --> 1.07 x 1001 = 1071.0700000000002   What is the best solution here?


Dropbox files in another location to norm

I use dropbox and very happy with it.  The only drawback I have with it is that I must place the files I want to share in the My Dropbox folder.  Is there anyway I can place the files in another folder on my PC and automatically sync between dropbox folder and another folder on my local pc?


inserting long text in a node with a fixed width

Using the following code, is it possible to insert the long text (in the node) inside a framed box with certain background colour, with a certain defined width and a height that accommodates the long text.      \documentclass{beamer} \beamertemplatenavigationsymbolsempty \usepackage{tikz} \usepackage{pgfplots} \begin{document} \begin{frame}[fragile,t] \frametitle{1} \begin{tikzpicture}[scale=.9, transform shape] \draw [thick,-latex](0,0) -- (6.2,0) node [black, xshift=.3cm, yshift=0cm] {$x$}; \draw [thick,-latex](0,0) -- (0,5) node [black, xshift=0cm, yshift=.3cm] {$u$}; \draw [ultra thick,blue] (0,2.84) -- +(-40:4.44cm) node [pos=.5,red] {x} node [pos=.5, xshift=4.8cm, yshift=.2cm] {very very very very very very very long long long long long long long text} node [pos=0,circle, draw, black, fill=black, scale=0.5]{}  node [pos=1,circle, draw, black, fill=black, scale=0.5]{}; \end{tikzpicture} \end{frame} \end{document}     to make it look like this


HP PSC 1410 all scanner's images are black

I have a HP PSC 1410 printer with scanner inside.  I've been scanning documents and images with it for the last couple of years.  Recently my scanner has stopped performing as excepted and i can't scan or copy images\documents.  My problem is that every images\document i'm trying to scan - the result from the printer is a black page.  I've been googling about this issue and couldn't find any helpful stuff beside replacing the whole printer - which is something i'm trying to avoid.  Any ideas ? I've read something about the shipping lock of the scanner but couldn't find any information about how to check it..


How to show $f=g$ almost everywhere  Let two real-valued measurable functions $f$ and $g$ be such that for any measurable set $E$ the integrals $\int_E f\,d\mu$  and  $\int_E g\,d\mu$ coincide.  Could you please help.  It seems obvious. we could define the integrals as charges. can we do sth from here. but I do not know how to approach.


Looking for a book about the moon being a spaceship with an AI

I read this in the late 90's if I recall correctly. Can't remember title or author.  American astronaut is doing a survey of back side of the Moon. He is shot down and captured by the AI that controls an immense spaceship hidden inside the Moon. In fact: the Moon is the spaceship, the outer layer (100 KM or so) of rock is just camouflage.    He becomes the new captain of the ship that was left empty after the crew was forced to leave the vessel in the aftermath of a mutiny. That mutiny was 10.000 years ago. The original crew (mutineers and loyalists) took refuge on Earth and have been fighting ever since. Both factions have hooks into Earth governments and their ongoing battles are mostly of the black-ops/espionage type. The new captain makes contact with the loyalists and eventually defeats the mutineers.    Some other details: Cyborg tech that enhances the crew: Stronger, faster, better reflexes, better health, longer live and direct mind-machine communication-interfaces.    The ship was originally stationed in Earth-orbit as a hidden outpost of a big space-empire. There is an alien race that sends a destruction-fleet every xxx thousand years through this arm of the Milky Way to wipe out any intelligent life. The ship is on guard-duty against that threat. The ship AI is getting very nervous as he has no crew and the alien invasion is about due.   I'm pretty certain it was the first novel in a multi-part series, but I never read the others and I would like to.


Openshift Wordpress site custom domain name 'www' doesn't work

I use Opemshift to host my Wordpress site. I use a custom domain name for my site. I have also added an alias for www.example.com.  I use Cloudflare for DNS and I have created a CNAME record for www.example.com to wp-myapp.rhcloud.com as instructed on the Openshift docs.  While my naked domain name works, example.com, prefixing it with 'www' leads to an infinite waiting mode.


I have several jobs. For each job, I often open few browser tabs with known URL. So, job 1 (http://sth,http://sth2,http://sth3) job 2 (http://sth4,http://sth5,http://sth6,http://sth7) Each time opening the browser, how could we restore a specific group of tabs? Is there any way to save a number of tabs into a group and I could open them with correct order by just a click?


Do I understand how spell slots work for druids and sorcerers correctly?

I'm new to D&D and am the DM playing with a group of lower-level players. I do not understand spell slots for druids and sorcerers, am I correct to say: Each day players "prepare" list of spells for that day, and place one in each spell slot to use later.  Is this correct? Can each spell be used only once per day? Do spells come from all spells for that level or only known spells? If it comes from "known spells", how does a druid or sorcerer add to their list of "known spells"?  I have a level 2 sorcerer who wants to use the same spell every round. We've played that he can use that spell every time, but only as many times as the spell slots he has. But, I think we misunderstand the rules. I've read the  and many answers on this site, and I've figured a lot of it out. I'm still confused about how the spell slots work, and which spells are available at a certain level.


PHP - removing invisible characters pre-MySQL insert

I copy & paste match lists from Betfair but they have dodgy hidden characters equivalent to "Â". This means that rather than "Arsenal v Reading - Tuesday 19:45" I get "ArsenalÂ vÂ ReadingÂ - Tuesday 19:45".  To try and address this I do the following:  $pos = strrpos($match,"Â"); echo "pre-replace: " . $pos . "
"; $trim_match = str_replace("Â","",$match); $pos = strrpos($trim_match,"Â"); echo "post-replace: " . $pos . "
"; $q2 = "insert into tab (`match`) values ('" . trim($trim_match) . "')";   The resulting output is:  pre-replace: 23 post-replace:    But the dodgy character is still inserted. What's the best way to keep this junk data out? It is not visible when UTF-8 is set in the page or in PHPMyAdmin but the hex('l v') of the bad data is "6CC2A076" which equates to a "Â" symbol according to ASCII converters


I've got a gpkg file with country borders and I'd like to draw a dashed line for those borders. However, when I set the style as a dashed line in QGIS I get this:  The problem is that the overlapping portions (the vertical section above where the dashed line looks almost solid) show up incorrectly. Is there an easy way to fix this with QGIS/GDAL/something else?


How is $\frac{dQ}{T}$ measure of randomness of system?

I am studying entropy and its hard for me to catch up what exactly is entropy.  Many articles and books write that entropy is the measure of randomness or disorder of the system. They say when a gas system is let expand the randomness increases etc. But they end up saying $\frac{\mathrm dQ}{T}$ is the measure of increase in randomness and is called the entropy.  Even if I believe that entropy is the measure of randomness of the system I don't understand:   How does $\frac{\mathrm dQ}{T}$ hold the information about the randomness of the system? How is entropy independent property of any system. I suppose that any two parameter in the equation $PV=nRT$ should completely describe the system. Why would we need entropy?   Thank you.


I have Ubuntu 16.04 LTS. But vim is not showing the proper syntax colors and also the mode in which you are like insert mode. So can anyone help me how to solve the issue?


Under what conditions is the answer box replaced with an "Answer this question" button?

Today, I stumbled upon a  to flag a spam post. I noticed that the 'new answer editor' which usually appears at the bottom of the page was replaced by an 'Answer this question' button:    Upon clicking it, a popup appears starting with     This question has more than 2 answers already.   So that's the reason it appears, but I was wondering what the full set of conditions is.  indicates Workplace has a custom threshold set to 'more than 2 answers'; it mentions  which upon testing seems to have a 'more than 5 answers' threshold. For most sites, it seems to be 'more than 30 answers'. Are there more exceptions? What about Meta sites?  Also, is there any reputation level/privilege above which you don't get this popup anymore?


How to guarantee that equals() and hashCode() are in sync?

We are writing a class which requires very complicated logic to compute equals() and hashCode(). Something along lines with:  @Getters @Setters @FieldDefaults(level=AccessLevel.PRIVATE) public class ExternalData {   TypeEnum type;   String data;   List<ExternalData> children; }    We do not construct these objects, they are deserialized from XML from external complex system. There are 20+ types and depending on type data can be ignored, or processed with children, or processed without children and comparison of data for each type of node depend on type.  We created equals() and hashCode() to reflect all those rules, but recently ran into an issue that hashCode got out of sync with equals causing equal objects to be added twice to a HashSet. I believe HashMap (and HashSet for that matter) are implemented this way in Java:  The implementation first put objects in buckets based on hashCode and then for each bucket checks equals. In unfortunate scenario where 2 equal object will go to different buckets they will never be compared by equals(). By "Out of sync" here I mean that they go into different buckets.  What is the best way to make sure equals and hashCode do not get out of sync?  Edit: This question is different from   There they ask about generic guidance and the accepted answer does not apply in my situation. They say "make equals and hashCode consistent", here I'm asking how exactly do I do that.


Is it OK to charge my iPhone with my iPad charger?

I have an iPhone 4 and an iPad.  Since the iPad really charges best off the wall charger I keep it plugged in, but I usually just charge the iPhone off the computer.  Although frequently if the iPad is charged I will charge the iPhone with the wall charger.  Now the Apple sales rep said he heard from someone who heard from someone that that would burn out the phone because the iPad charger is 10 watt instead of 5 watt.  It is true that it is twice as many watts.  I said that I thought it shouldn't burn out the phone because a device should only pull as many watts as it needs, so the watts were irrelevant.  He said that made sense, but he didn't really know.  So I thought I would ask the experts.  Has anyone had their iPad charger fry an iPhone or iPod?  Am I correct in my understanding of watts in chargers?  Is there an official word about the iPad charger causing trouble with other devices?  Have I already voided my warranty?


Ubuntu Terminal, what is its executable name?

I would like to launch the ubuntu terminal from inside fluxbox (I don't use Unity).  However I can't manage to find the command name to launch this application ?  What's its name ?


Can aws vertical scaling of ec2 instance support 100,000 users per day?

I have a link sharing site (think reddit). It is hosted on godaddy deluxe shared hosting now. I am planning to migrate it to aws.  I have seen an aws webinar on scaling till 10 million users. But basically it just says beyond an extent you can't scale in a vertical manner so choose to scale in a horizontal manner from the beginning itself.  I don't need to support 10 million users. Assume that i need to support 100,000 users daily. At most the site will have say 1000 concurrent users.  Use Case   Users will post links to the site. Only one in 1000 users will post links. Most users just search the site for links, read the description etc. About 5000 comments will be made on the site every day. It is mainly a text based site. There are very little images on the site except user avatar and banner, both of which are limited at 2MB.  The images are stored in the DB. usual features of a forum like signup,login, account etc are present.   Planned Architecture   1 EC2 instance 1 RDS instance 1 Route 53 Zone 1 Elastic ip 1 s3 (only for backup)   I plan to scale using this simple method -  Start with say t2.micro, as the user base grows simply upgrade the ec2 instance. The same goes for the RDS instances.  I know that 1 EC2 or RDS makes it a single point of failure. If any of these break i plan to terminate that instance and start an identical one from an image/backup. I am okay if the site is offline for 1 hour every 30 days.  Please keep in mind that i have no one to assist me and this is a solo effort. I can find someone to assist on the aws side if it hits users.   Can i support 100,000 users in this manner? At what breakpoints should i upgrade to the next Ec2 instance till the 100,000 users/1000 concurrent users? (eg. Till 5 concurrent users- t2.micro/db.t2.micro, Till 40 concurrent users- EC2 Instance type 2/Rds instance type 2 etc.) Is there anything else that i have not considered/ have to consider before going ahead with this plan?


Limit of derivative function at infinity

$f$ is a differentiable function on real line such that $$\lim_{x \to \infty}f(x)=1$$ and $$\lim_{x \to \infty}f'(x)=\alpha$$. Then what can be said about $\alpha$  $\alpha=0$ $\alpha$ may not be $0$ but $|\alpha| \le1$ $\alpha\geq1$ $\alpha\leq-1$   I cannot think of any viable option other than 1,but i cannot prove it. Any hint or solution would be appreciated!


What does $\frac{1}{1+\frac{2}{2+\frac{3}{{\vdots}}}}$ evaluate to?

I was curious what does $$\cfrac{1}{1+\cfrac{2}{2+\cfrac{3}{3+\cfrac{4}{\vdots}}}}$$ evaluate to. Empirically, I observed that it equals approximately $0.5819767$, and a calculator found that this value agrees with $\frac{1}{e-1}$ to at least 8 places. Is $\frac{1}{e-1}$ the exact value of this continued fraction? If this is true, is this result new? And how could the equivalence be proved?


TikZ set node label position more precisely

This seems like it should be really easy but I can't seem to find it anywhere...  I'd like to be able to fine-tune the positioning of a node label.  I'm aware of the \node[label=above/below/etc:{label}] (x) {}; syntax, but that doesn't seem to give you many options on where the label goes. I'd like to be able to place the label slightly closer or farther away, or maybe in a direction other than the 8 presets available.  \tikz[label distance=x] isn't a good solution because I need it to be node-specific.


i have question i got error like this [[Ljava.lang.Integer;@26f0a63f]

i have source code like this public class Solution {       private static List<Integer[]> twoSum(int[] numbers, int targets) {          Map<Integer, Integer> arrayMap = new HashMap<>();             List<Integer[]> pairList = new ArrayList<>();                          for (int i = 0; i < numbers.length; i++) {                 if (arrayMap.containsKey(targets - numbers[i])) {                     Integer[] temp = { arrayMap.get(targets - numbers[i]), i }; // Put the previous and current index                     pairList.add(temp);                 }                 else arrayMap.put(numbers[i], i);             }             return pairList;         }      public static void main(String[] args) {             // TODO Auto-generated method stub             int[]nums = {2, 7, 2, 11, 15};              int target=9;             System.out.println(Arrays.toString(nums));             List<Integer[]> index =twoSum(nums, target);             System.out.println(index.toString());                      } }  but i want to run i got error like this [[Ljava.lang.Integer;@26f0a63f]  how to fix my problem ?


How can I assign a Func conditionally between lambdas using the conditional ternary operator?

Generally, when using the conditional operator, here's the syntax:  int x = 6; int y = x == 6 ? 5 : 9;   Nothing fancy, pretty straight forward.  Now, let's try to use this when assigning a Lambda to a Func type. Let me explain:  Func<Order, bool> predicate = id == null     ? p => p.EmployeeID == null     : p => p.EmployeeID == id;   That's the same syntax, and should work? Right? For some reason that doesn't. The compiler gives this nice cryptic message:     Error  1   Type of conditional expression cannot be determined because there is no implicit conversion between 'lambda expression' and 'lambda expression'   I then went ahead and changed the syntax and this way it did work:  Func<Order, bool> predicate = id == null     ? predicate = p => p.EmployeeID == null     : predicate = p => p.EmployeeID == id;   I'm just curious as to why it doesn't work the first way?  (Side note: I ended up not needing this code, as I found out that when comparing an int value against null, you just use object.Equals)


Product of two binomial coefficients in terms of linear combinations of binomial coefficients

For $n,a,b$ natural numbers with $a+b \leq n$, can we find positive rational numbers $c_1, \ldots, c_{a+b}$ such that $$ {n \choose a}{n \choose b} = \sum_{k=1}^{a+b}c_k{n \choose k}? $$ Is there a formula?  Here are three examples with $n = 5$: \begin{align*} {5 \choose 1}{5 \choose 1} &= {5 \choose 1} + 2 {5 \choose 2};\\ {5 \choose 1}{5 \choose 3} &= {5 \choose 1} + {5 \choose 2} + \dfrac{3}{2}{5 \choose 3} + 4 {5 \choose 4};\\ {5 \choose 2}{5 \choose 3}&= 3{5 \choose 1} + 3 {5 \choose 2} + 3{5 \choose 3} + 3{5 \choose 4} + 10{5 \choose 5}. \end{align*}


How can I know the default PGF line width?

Is there some macro that will tell me what the default PGF line width is? I have tried creating my own macro by cloning \pgflinewidth before it has been modified, i.e.  \let\defaultlinewidth\pgflinewidth   but \defaultlinewidth seems to be affected by \pgfsetlinewidth anyway, and change to whatever \pgflinewidth is. So, the problem is that after I have called \pgfsetlinewidth, I don't know what the default pgf line width is anymore. Is there some way to get around this?


Here is a problem from Herstein.     Let G be a finite abelian group so that the equation $x^n=e$ has at most $n$ solutions in $G$ for every positive integer $n$. Show that $G$ is cyclic.   I will have to basically show that there exists an element $g$ in $G$ having order $o(G)$.   I showed that such an element exists if $o(G)=p_1p_2...p_k$ where $p_i$ are primes. But I could not proceed if $o(G)=p_1^{a_1}p_2^{a_2}$. I feel that if I can prove this I will be able to extend.


As I go into terminal with Ubuntu 12.04 64 bit. I type in `sudo apt-get update. I enter in the required password. The termianl with process the request toward checking if there are any updates! As it get's down to the final conclusion of how long it took to process, I get this error. Here is a picture of the error!    I don't understand the error! I don't have a W: drive! I have seen this error with many users, but I can not fix this error! If you have a good fix for this error, I would appericate the advice and solution! Thanks


How can I make a Python script parse command line arguments like a Unix command?

I have a Python utility script that accepts arguments in the commandline and executes tasks against an open source search tool called .   But simply put, here is how it's currently being used:  Myscript.py create indexname http://localhost:9260 Myscript.py create indexname http://localhost:9260 IndexMap.json   I would like to make it so that the user of the script doesn't have to remember the order of the arguments to the script. How can I enable this in my script? I was thinking along the lines of a Unix-like argument passing. For example:   import os import sys import glob import subprocess   # collect command line arguments commandline_args = sys.argv  # How to use this simple API: #   create indexname http://localhost:9260 IndexMap.json  command_type = commandline_args[1] index_name = commandline_args[2] base_elasticsearch_url = commandline_args[3] file_to_index = sys.argv[4] if len(sys.argv) > 4 else None   def run_curl(command, url):     cmd = ['curl', command]     url = url.split(' ')     print 'sending command: '     print cmd+url         return subprocess.check_output(cmd+url)  if (command_type == 'delete'):     print 'About to run '+ command_type + ' on Index: ' + index_name     command = '-XDELETE'     composed_url = base_elasticsearch_url + '/' + index_name + '/'     output = run_curl(command, composed_url)     print 'output:'     print output  # create Index # works! # curl -XPOST 'localhost:9260/icrd_client_1 -d @clientmappings.json if (command_type == 'create'):     print 'About to run '+command_type+' for Index: '+index_name+' from filename: '+file_to_index     command = '-XPOST'     composed_url = base_elasticsearch_url + '/' + index_name +' -d ' + '@'+file_to_index     output = run_curl(command, composed_url)     print 'output:'     print output


What is the benefit of using === operator to test for undefined instead of using == operator?

I usually test whether a JavaScript variable is defined or not, using the following test:  if (typeof a == 'undefined')     a = 'default value'   However, I have seen many people suggesting that it is safer to use the following instead:  if (typeof a === 'undefined')     a = 'default value'   I am aware of the difference between == and === operators but I am unable to understand why typeof a == 'undefined' could be unsafe.  Could you please a scenario in which the first code example is unsafe or could lead to issues? Also, what are the advantages of using the latter syntax over the first?


Can both my boys have a user on minecraft PC.

My son got MineCraft PC for his birthday.  The account is under my e-mail and he has a name in the game (my terminology may be off as i do not play the game).  My other son would also like to play MineCraft, but have his own name (character???).  Can that be done?  It doesn't seem logical that I'd have to download 2 Minecraft games.  Please let me know how this works.


Slowly running watch or slow running watch

My question is:     "The Egyptian Calendar was like a -------watch."   I think the answer "slowly running watch" is grammatically right. But on the other hand, "slow running watch" is most common in use nowadays. I would like to know which answer you prefer.


When best to use Multi-Zone/Matrix, Spot, or Center-Weight exposure metering modes?

What are Multi-Zone/Matrix metering, Center-Weighted metering, and Spot metering? What about Partial?  Is there a good rule of thumb, or a few pointers, on when best to use each exposure metering mode?


How exactly is the stoppage time determined?

What is the formula (I'm not sure it exists at all, maybe it's just a random number) to determine the amount of extra (added) time in futbol (soccer) that get's added after the obligatory 90 minutes.   I think that it should be the sum of every action that wastes time. Like injuries, corners, etc. I almost see, from 1 minute, up to 5 minutes, never more than that.     Related:


Can't answer my own (old, protected) question

I'm logged in to Physics.SE, I have 73 rep, and yet I noticed I can't answer :  Supposedly the reputation requirement is only 10, yet I'm prevented from posting:  Since I hardly use this account, here's the entire /reputation: total votes: 6 -- bonuses   (100) -- 2011-08-18 rep +100  = 101         8    128510 (-50) -- 2014-08-19 rep -50   = 51          16   200654 (2) -- 2015-08-16 rep +2    = 53         -- 2016-07-18 rep 0     = 53          2    199721 (10) -- 2017-03-16 rep +10   = 63          2    199721 (10) -- 2017-06-03 rep +10   = 73         -- 2020-06-11 rep 0     = 73          ** rep today: 0 ** rep this week (2020-09-20 - 2020-09-26): 0 ** rep this month (2020-09-01 - 2020-09-30): 0 ** rep this quarter (2020-07-01 - 2020-09-30): 0 ** rep this year (2020-01-01 - 2020-12-31): 0 ** rep from bonuses: 100 ** total rep 73 :)  days represented 7 rep cap was reached via rep from upvotes *only* on 0 days earned at least 200 reputation on 0 days earned 2 reputation from suggested edits


I have a Google spreadsheet. There is a colour column. Every row has a colour, Red, Yellow, Green etc. I want to be able to filter out say all rows that are Red, all rows that are yellow, all rows that any colour except Green, Green rows only etc.  Any tips on how to do this? I want to do this so the user viewing the spreadsheet can do it dynamically.


Prove that if we redefine the key space, we can assume Gen chooses a key uniformly

I am working on problem 2.1 in Introduction to Modern Cryptography 2nd edition by Katz and Lindell.     2.1) Prove that by redefining the key space, we may assume that the key generation algorithm $\textsf{Gen}$ chooses a key uniformly at random from the key space without changing $\Pr[C=c\mid M=m]$ for any $m,c$   We are told to define the key space to be the set of all possible random tapes for the generalized algorithm $\textsf{Gen}$.  I don't understand how we are supposed to prove that this algorithm $\textsf{Gen}$ chooses a key uniformly without knowing the algorithm itself. I am not really sure where to even start with this as I am new to proofs and crypto in general, and and all help will be useful!  What I do know:  $\textsf{Gen}$ is a probabilistic algorithm that outputs some key $k$ chosen according to some distribution. The finite key space $\kappa$ is the set of all possible keys that can be output by $\textsf{Gen}$


Example of a monomorphism and epimorphism that is not isomorphism.

I'm starting with a course of Introduction to Category Theory, and perhaps is dumb what I'm asking but I'm looking for an example of a monomorphism and epimorphism that is not isomorphism. Can you help me?  Thank you in advance!


I'm running 18.04. When I try to upgrade to LTS version 20.04 using Software Updater I get message that 19.10 is available.  I've set the upgrade line to "any new version". I've also tried using the command line in the terminal with same results. This has persisted since April 23rd - date 20.04 was released. My system is up to date


If I have the fighter's Extra Attack feature and the warlock's Thirsting Blade eldritch invocation, how many attacks can I make?

I am playing a half-orc fighter level 7 and warlock level 3. When I gain a warlock class level, I will gain an Eldritch Invocation, and I will pick Thirsting Blade. How many attacks can I make, since I have both Thirsting Blade and Extra Attack?


"He was telling me that he is going..." vs. "He told me that he is going..."

Is it right to say   He was telling me that he will go on a vacation next week.  while recounting your experience?  Even though "he told me that he is going..." seems more appropriate, I would still like to know if the above mentioned expression sounds okay or not.


It's always drilled into us that we shouldn't use comma splices. They're bad, to be avoided and poor form.  But why? What makes the comma a faulty choice in something like this:     I never liked school, it was boring and repetitive most of the time.   It could be replaced with a semicolon, dash, period or colon and be "correct." Yet to a fair amount of people, the comma seems fine. If it weren't, it wouldn't be found so often in online forums, text messages, emails and so on.  What makes the comma between two sentences an error?


no space in disk : sudo apt-get clean not working

Filesystem                   Size  Used Avail Use% Mounted on /dev/mapper/ubuntu--vg-root  292G  174G  103G  63% / none                         4.0K     0  4.0K   0% /sys/fs/cgroup udev                         902M  4.0K  902M   1% /dev tmpfs                        183M  1.3M  182M   1% /run none                         5.0M     0  5.0M   0% /run/lock none                         913M  156K  913M   1% /run/shm none                         100M   48K  100M   1% /run/user /dev/sda1                    236M  185M   39M  83% /boot   I use ubuntu 14.04


There is a big number of Stack Exchange sites, so much so that sometimes it's difficult to choose the more appropriate site for our questions. Sometimes there is more than a site that fits to our question. For example, when I have a question about a engineering problem governing by a differential equation and that I want to solve with a computer algebra system implemented in a library in python lenguage. That type of question covers several subjects and it's complicated to choose 1 site for that question.  I was search about how I can find the Stack Exchange site which fit to my question, and I found the next question:      After read that question, I consider that searching the site's tags and reading their tag wikis and to see the frequency of the use of the tag helps a lot to know if my question fits to the site. But search the tags through the all possible sites is a hard work, so I would like to know if exist a way to list all the tags used throught all the Stack Exchange sites. This will help us to find a specific tag that fits to my question and then to find which SE site this tag belong to.  Is there a way to list all the used tags through all the Stack Exchange sites? or is there a webpage that contain that list of all tags of all Stack Exchange sites?


How can I return actual JSON using Drupal?

I'd like to implement a simple AJAX function locally that allows me to autocomplete node titles of already existing nodes as the user types. To that end, I need the ability to have an API that I can search on node titles. The problem is that when I output raw JSON, it comes surrounded by tags. So, no matter what I do, I keep getting...
 {json here}
         I've tried implementing a custom page template that only outputs content already, that produced the same results. Here is how I am currently doing this, in my module file...  <?php  /**  * Implementation of hook_menu()  */ function content_relation_menu() {     $items = array();     $items['api'] = array(         'title' => 'Search',         'page callback' => 'content_relation_get',         'access callback' => TRUE,         'type' => MENU_CALLBACK,     );      return $items; }  function content_relation_get($term = '') {     drupal_add_http_header('Content-Type', 'application/javascript; utf-8');     $var = json_encode(         db_query("SELECT nid,title FROM {node} WHERE title LIKE :title LIMIT 5", array(":title" => $term.'%'))->fetchAll()     );     echo $var;     exit(0); }   How can I return JUST raw JSON?


I need to display drop down list with headers  values are retriving from database i need to  display like  Maharashtra    Mumbai Nasik Pune    UttarPradesh   Lucknow Meerut Noida Ghaziabad   Uttrakhand    Dehradun Rishikesh   Haridwar


How do you select a point using the API as the primary point selection?

I've run into some difficult selecting a point as the "primary selection" (not sure if this is proper terminology) I've been using this function to select a single point from a mesh: def select_append_point(index):     #getting proper mode for selection (its object, this is counter intuitive)      bpy.ops.object.mode_set(mode = 'EDIT')      bpy.ops.mesh.select_mode(type="VERT")     bpy.ops.object.mode_set(mode = 'OBJECT')     #selecting point from index number     cube_ob.data.vertices[index].select = True     #note I show how cube_ob is defined below      #returning to edit mode     bpy.ops.object.mode_set(mode = 'EDIT')   This results in a selection like this:  it is orange in the viewport, therefore not a primary selection I'd prefer a selection like this:  It is white in the viewport and a primary selection. This is for the application of using the following code: bpy.ops.mesh.shortest_path_select(edge_mode='SELECT')  that code outputs this between two selected points:  But does not work as intended for an appending application unless one of the points is white not orange. Thank you for any help!!! How cube_ob is defined: cube_ob = bpy.context.active_object bpy.context.view_layer.objects.active = cube_ob cube_ob.select_set(state=True)


PostGIS snap line segment endpoint to closest other line segment

I have a PostGIS table of singlepart line segments that I've run the ST_ChaikinSmoothing function on. Smoothing all of the line segments worked great, but these simplified geometries created small gaps between the other line segments in the table. (It's a network of flowlines) I need to snap the endpoints of each linestring to the closest segment of another line in the table.   I was directed to  about snapping lines, but I think it is snapping features in one layer (line) to features in another layer (input). I always struggle to comprehend PostGIS examples that use abstract text geometries in the queries as opposed to referencing tables of existing features.  My query below is returning an empty table with point geometry. I can successfully run each of these three functions individually to locate the points on the lines, but I can't figure out what i'm missing to snap the lines and create line geometries.  "geometry" is the name of my geometry column in the smoothed_lines table  create table snapped_lines as ( SELECT ogc_fid, name, (ST_LineInterpolatePoint(geometry,ST_LineLocatePoint(geometry,ST_EndPoint(geometry)))) as geometry from smoothed_lines);     UPDATE: Sample dataset:   The answer from @gabriel-de-luca below does snap the smoothed lines to the original lines based on matching id's, but ST_Snap moves all vertices in a linestring, not just the end nodes and wrecks the smoothness of the input features.   example after running this ST_Snap query:


I know that isomorphism has a well known symbol, but what about diffeomorphism?


I have more than hundred directories named SP_[number]_date. I'd like to rename all to just SP_[number].  I can only figure out how to do that by mv SP_1_date SP_1 but that will take ages. Can I rename all at once? I thought that I could do something like for num in ./*; do mv SP_$num_date SP_$num; done but it doesn't do the trick.


I have the following graph, where I want to label the edges. Is there a way I can integrate this in to the draw command?  { \begin{figure} \begin{center} \begin{tikzpicture}[every node/.style={circle, draw, scale=.8, fill=gray!50}, scale=1.0, rotate = 180, xscale = -1]  \node (1) at ( 2.55, 3.0) {1}; \node (2) at ( 3.87, 0.92) {2}; \node (3) at ( 6.85, 0.92) {3}; \node (4) at ( 8.17, 3.0) {4}; \node (5) at ( 6.85, 5.0) {5}; \node (6) at ( 3.87, 5.0) {6}; \node (7) at ( 10.2, 3.0) {7}; \node (8) at ( 12.2, 3.0) {8};  \draw (2) -- (1); \draw (3) -- (2); \draw (4) -- (3); \draw (7) -- (4); \draw (8) -- (7); \draw (6) -- (1); \draw (5) -- (6); \draw (4) -- (5);  \end{tikzpicture} \caption{Weight 2} \label{fig:wt2} \end{center} \end{figure} }


How do I force a div element to extend to the bottom of the page?

I have been playing with CSS height property for a while, but I still can't find a solution.  This is my CSS:  html{     height: 100%; } body{     margin:0px;      padding:0px;      min-height:100%; } #container{     position: relative;     padding:40px;     margin-top:2%;     background-color:rgba(0, 0, 0, 0.7);     margin-bottom:2%;     height:auto; }   Is there a way to fix this using CSS or may I use a javascript function?


In "The Martian" why would he use hex over base 10 values for the alphabet?

The fastest way to communicate the English language would be just having the camera point at letters. He explains that it would be too difficult to tell what the camera was pointing at. Since the limiting factor is the amount of discrete directions that the camera can point, why would you use hex over base 10 values to translate into letters? Instead of 16 directions, you would only have to discriminate between 10. You are already having to translate from the numeric representation to the letter representation anyway. I assume you would need either a delimiter or an agreed upon "word space" (each value will be padded with zeros if it uses less than the max word size).


Inputting CSV in QGIS graphical modeler and defining its geometry

Is it possible to have a model in QGIS graphical modeller which accepts a CSV with geometry fields and then allows you to use them for the rest of the model as if it was a vector file?  This is required so I can bypass having to import the CSV into QGIS and defining it there before adding it to a model.


Will cropping an FX image to DX size have the same end detail for sensors with the same MP?

Let's say I have a 90mm and an 135mm lens, and Nikon's 24mp full frame and 24mp APS-C DSLR. Assume they are the same optically.  Now, based on what I understood, doing a DX-crop on the image taken by 90mm lens on full frame camera will give you exactly same view of an image taken by 135mm on full frame, with less pixel. But, 24mp when cropped, will still provide enough pixel for viewing on computers. So, in terms of sharpness and details (I don't know their difference), will it be the same with an image taken with 135mm lens? How about when viewing on 100% size?  I find this confusing because, when you shoot further away, you will lose some tiny details, vs if you just shoot it with a longer lens. But that will mean APS-C inherently takes in less details than full frame, which doesn't sounds right. Or does using APS-C gives more details than doing a DX-crop on a full frame body? Is it because it gives more pixel? I read that pixel got nothing to do with sharpness, but in this case?  Sorry for the messy questions, this is so confusing that I am unable to tidy it up in my mind. Thanks!


Does drawing multiple cards count individually?

Say if I have the emblem of  (Whenever you draw a card, you may exile target permanent) out, and cast  (Draw three cards, then put two cards from your hand on top of your library in any order). How many times does the emblem trigger?


Instance_eval does not work with do/end block, only with {}-blocks

If I have a class:  class KlassWithSecret   def initialize     @secret = 99   end end   and run:  puts KlassWithSecret.new.instance_eval { @secret }   it prints 99, but if I run:  puts KlassWithSecret.new.instance_eval do   @secret end   It returns an error: `instance_eval': wrong number of arguments (0 for 1..3) (ArgumentError)  Why can't I use do/end blocks with instance_eval?  P.S. I am using Ruby 2.1.0.


Maximal and Prime Ideals in a finite Ring of Functions

I was trying to solve a question asked in some PhD entrance exam but I got stuck in some options. The question is:  Let $R$ be the set of all functions from the set $\{1,2,...,10\}$ to $\mathbb{Z}_2$. Then $R$ is a commutative ring with pointwise addition and pointwise multiplication of functions. Then which of the following statements are true?  $R$ has a unique maximal ideal. Every prime ideal of $R$ is maximal. Number of Proper ideals of $R$ is $511$. Every element of $R$ is idempotent.   Now it is obvious that statement $4$ is correct. And I found that option $1$ is false because for each $a \in X$, the set of all functions which maps $a$ to $0$ forms a maximal ideal (consider the kernel of evaluation at $a$, i.e. the kernel of the map $T$ from $R$ to $\mathbb{Z}_2$ sending $f$ to $f(a)$. From here we get that $R/\ker T$ is isomorphic to $\mathbb{Z}_2$ and hence the ideal will be maximal). So, we get at least $10$ maximal ideals. But I could not get any hint in proving or disproving options $2$ and $3$. Any help would be appreciated.


What is the command line way of sending files to the recycle bin?

Is there a command line program that can send files to the recycle bin? This is on XP and Vista.


I had submitted a manuscript to an ESCI journal. It has been over 1 month since I submitted but the status shows "with editor".  I mailed the editor to check the status of my manuscript. The editor informed me that he had sent the manuscript to some referees but he has not received any reply from the reviewers. He/She further said that if I want, I may consider submitting my paper elsewhere.  How long should I wait for the reviewers to give a decision whether they will review my manuscript or not?  Also my deadlines for submission are due in 2-3 months, i.e. I need to get my first submission within 2-3 months.  What time can be considered enough to withdraw my submission?


Can i set 443 as default web port which means it can only be accessed via https and no port 80

As title says,  I want to set my apache to listen on 443, and will configure SSL.   So, My Question  is :-  1). Does that mean, i will not have port 80 or any other port which is no ssl ? 2). My site can only be accessed via https and no http ? Thanks


Does negative vote count in score gained in tags after deletion

If the post got negative votes and is deleted, does that negative vote after deletion count in the score of tags.(Reputation lost is credited back but what about the score of the tags involved in them)  .


For which natural numbers are $\phi(n)=2$?

I found this exercise in Beachy and Blair: Abstract algebra:     Find all natural numbers $n$ such that $\varphi(n)=2$, where $\varphi(n)$ means the totient function.   My try:  $\varphi(n)=2$ if $n=3,4,6$ and I think that no other numbers have this property. So assume $n>7$.  Case 1: $n$ is prime, since $\varphi(n)=n-1$ for primes, no numbers here will have the desired property  Case 2: $n$ is of the form $n=p^k$ for some prime $p$ and $k\in\mathbb{N}, k\ge 2$. By Eulers formula we get $$ \varphi(n)=p^k-p^{k-1} $$ which clearly is greater than $2$ since $n>7$.  Case 3: $n$ is the product of different primes and is squarefree (each prime comes up at most once in the prime factorisation of $n$). Assume  $$ n=\prod_{i=1}^{m} p_i $$ by Eulers formula $$ \varphi(n)=n\prod_{p_i \ prime \ factor}\Big(1-\frac{1}{p_i}\Big) $$ which gives $$ \varphi(n)=p_1p_2\cdot\ldots\cdot p_m\Big(1-\frac{1}{p_1}\Big)\Big(1-\frac{1}{p_2}\Big)\cdot \ldots\cdot \Big(1-\frac{1}{p_m}\Big) $$ rearranging and multiplying out gives $$ (p_1-1)(p_2-1)\cdot\ldots\cdot (p_m-1) $$ which once again has to be greater than $2$ since $n>7$.  Case 4: $n$ is a product of different primes and not squarefree. This is similar to Case 3 but we get some more factors in the product so if there were no integers in Case 3 there cannot be here eighter.  Now my first question is: Is my reasonning correct? Ususally when I have to divide the solution up into so many cases I feel that I haven't grasped the problem properly, but I couldn't come up with anything better.  Any suggestions?  Thank you in advance


Would it make sense to use wool batting like  as a window quilt? Why or why not? What factors would affect its suitability? For context, I propose using this on the inside of one of those  in the US midwest.


LAS dataset to raster with ground points only

I'm trying to make a raster from an LAS dataset. I want to only use points classified as ground, but I can't figure out how to do this. What I've tried is:   Create LAS dataset from 2 .las files.  Filter dataset on ground using LAS Dataset to raster tool.  Pick the dataset and use linear interpolation on average cell assignment type.   The result is a raster with all points including non-ground points.  When I'm in the LAS Dataset to raster tool I'm choosing an external file that doesn't get affected from what I've done in the LAS Dataset toolbar. How do I make the filter affect the dataset before turning it into a raster?


What is the difference between id & class

I know for id we have to use '#' symbol & for class '.' symbol. But i dont know what class does & id does i use both for styling css. Can any one help me when i want to use id & when class.is there is any major difference.


Book that I read long ago. I believe that the word "chaos" is in the title

In the book, bombs that had traveled from another galaxy were causing great damage to human planets. Ultimately, the main character makes a journey to the other galaxy and finds the ruins of the civilization that launched the bombs. It turns out that the aliens were able to catch a glimpse of a future in which we are walking around in the ruins of their civilization and they assume that we destroy them. So they sent out the bombs in the hope of eliminating that future, but it was their bombs that eventually caused us to visit their galaxy and we had nothing to do with the collapse of their civilization.


help  displays information about builtin commands. What is the source of help? Does it maintain a database for builtin commands, or does it read some files of each builtin commands (similar to the manpage of each utilities)?  Sometimes I find its information seems to expand that by --help  $ cd --help bash: cd: --: invalid option cd: usage: cd [-L|[-P [-e]]] [dir]  $ help cd cd: cd [-L|[-P [-e]]] [dir]     Change the shell working directory.      Change the current directory to DIR.  The default DIR is the value of the     HOME shell variable.      The variable CDPATH defines the search path for the directory containing     DIR.  Alternative directory names in CDPATH are separated by a colon (:).     A null directory name is the same as the current directory.  If DIR begins     with a slash (/), then CDPATH is not used.      If the directory is not found, and the shell option `cdable_vars' is set,     the word is assumed to be  a variable name.  If that variable has a value,     its value is used for DIR.      Options:         -L  force symbolic links to be followed         -P  use the physical directory structure without following symbolic         links         -e  if the -P option is supplied, and the current working directory         cannot be determined successfully, exit with a non-zero status      The default is to follow symbolic links, as if `-L' were specified.      Exit Status:     Returns 0 if the directory is changed, and if $PWD is set successfully when     -P is used; non-zero otherwise.   I thought help extract the help part of the executable, but for a  python script , it isn't  $ help ./pdf-merge.py bash: help: no help topics match `./pdf-merge.py'.  Try `help help' or `man -k ./pdf-merge.py' or `info ./pdf-merge.py'.  $ ./pdf-merge.py --help usage: pdf-merge.py [-h] [-v] [--ask] [--output OUTPUT] [--title TITLE]                     [--author AUTHOR] [--keyword KEYWORD] [--pdftk PDFTK]                     [--gs GS] [--pdfmarks PDFMARKS] [--unicode]                     PDF [PDF ...]  Merge PDFs preserving bookmarks. Thanks to Larry Cai for suggesting that Unicode be supported and for discussion about the `--pdfmarks` option.  positional arguments:   PDF                  an input PDF to merge  optional arguments:   -h, --help           show this help message and exit   -v, --version        show program's version number and exit   --ask                pause for manual pdfmark tweaking   --output OUTPUT      name of the output PDF   --title TITLE        title of output PDF   --author AUTHOR      author of output PDF   --keyword KEYWORD    keywords for the output PDF   --pdftk PDFTK        path to the pdftk executable   --gs GS              path to the gs (Ghostscript) executable   --pdfmarks PDFMARKS  path to pdfmarks file. If not given, a temporary file                        is used. If given and the file is missing, execution                        will stop after the file is created (before the                        Ghostscript run). If given and the file exists, no                        attempt will be make to use pdftk to generate the mark                        file (I assume your input file is what you want).   --unicode            instead of merging PDFs, convert PDF-formatted unicode                        strings. For example `--unicode '<FEFF03B103B203B3>'                        \u03b1\u03b2\u03b3`


Why is the sum function improperly rounding two floats

Why is python returning 5.789999999999999 for sum([1.23, 4.56]) and how do I get it to return the expected 5.79


Add "hasImage:1" or "img:1" advanced search operators

There are some great posts on SO and other SE sites with explanatory images that give a better understanding of the problem or its solution.  Recently I was searching for a particular post I had come across that had an image that easily explained java collections in a simple way.  I found it hard to search for. It would be great if we had a new search operator 'hasImage:1' like the existing 'votes:1' (searches post with minimum number of votes), 'views:1000' (with minimum 1k views), etc.  'hasImage:1' would return posts containing a image, and matching the other search keywords.  How do people feel about this?  EDIT  It can be simpler, just img:1 or image:1 as proposed by other users.


Compact for limit point and continuous function

If $X$ is limit point compact, i.e., every infinite subset of $X$ has a limit point in $X$,  and $f:$ $X\mapsto Y$ is continuous function, is $f(X)$ limit point compact?.


Why do i get different results from two servers that located in the same destination network?

There's two servers with the same network IP, and the only difference between them is the last two numbers like: xx.xx.15.247 and xx.xx.66.178   When i try the command Tracert (Traceroute) to test the ping and to see what hops does it take to reach the destination server, i get different ping times and different forward path results which is strange because they are all located in the same company host.  Is there something wrong? Shouldn't it take the same path too?


How can anything ever fall into a black hole as seen from an outside observer?

The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-observer.  If this is the case how can anything ever fall into a black hole.  In my thought experiment I am in a spaceship with a powerful telescope that can detect light at a wide range of wavelengths.  I have it focused on the black hole and watch as a large rock approaches the event horizon.  Am I correct in saying that from my far-away-position the rock would freeze outside the event horizon and would never pass it? If this is the case how can a black hole ever consume any material, let alone grow to millions of solar masses.  If I was able to train the telescope onto the black hole for millions of years would I still see the rock at the edge of the event horizon?  I am getting ready for the response of the object would slowly fade.  Why would it slowly fade and if it would how long would this fading take?  If it is going to red shift at some point would the red shifting not slow down to a standstill? This question has been bugging me for years!  OK - just an edit based on responses so far.  Again, please keep thinking from an observers point of view.  If observers see objects slowly fade and slowly disappear as they approach the event horizon would that mean that over time the event horizon would be "lumpy" with objects invisible, but not passed through?  We should be able to detect the "lumpiness" should we not through?


Are things shown but not named in Star Wars movies still G-level canon?

If an alien of a certain species is shown (but never named, or does anything) in Star Wars movie, and then given a name/backstory/whatnot in a C-level book, is that alien species (and the facts about it) considered a G-level canon or a C-level canon?   Or is it nuanced? (e.g. the existance is G-level but any details are still C-level)?


Behavior of $\sum_{n=1}^\infty n^{-1}z^n$ on the circle of convergence

Consider the following complex power series :$$\sum_{n=1}^\infty\frac{z^n}{n}$$ The radius of convergence of this series is $1$ and the series is divergent for $z=1$. I want to know what are the values of $z\in C:=\lbrace z\in\mathbb{C}: |z|=1\rbrace$, the circle of convergence, for which the given series converges.


Can I use "No, at all" instead of not at all"?

When we were asked, "Would you mind...?" we answered, "No, not at all."   But can I use "no at all" instead of "not at all?"


I am having problems with proving the following formula by using induction.  $${r \choose r} + {r+1 \choose r} + {r+2 \choose r} + ... + {n \choose r} = {n+1 \choose r+1}$$  It is stated in the question that the r is arbitrary but fixed, which I also don't understand. If anyone could guide my how to solve this I would be very grateful.


Different representation of bash in 'ps -f' command

I have two bash running; one is Terminal application that runs bash, the other one is xterm application that runs bash.   With ps -f, I have -bash one, and bash at the other.  What makes this difference?


Schema.org Event does not appear in Google Search and Bing

I always wondered how freelancers and businesses add their events to Google and Bing to make them searchable like this:    Finally I found some forum explaining that Google read them from JSON-LD format which you should embed into a web page on your web site.   I followed instructions and made one for my site in the beginning of the week for the upcoming weekend. However 5 days since it still not shown up if you type "events in walnut creek ca this weekend".  Here is .  I've also added JSON-LD for the business itself on a home page.  Any ideas what did I do wrong?


How to change the guest session keyboard layout?

I use the Dvorak keyboard layout. When I switch to a guest session it defaults to the Dvorak layout as well. Unfortunately this only produces gibberish for most people typing.  Is there a way to set the default guest session keyboard layout?


"the girls' nose" or "the girls' noses": which means the nose of many girls?

"the girls' nose" or "the girls' noses"?  We are talking about the nose of many girls.


How do I highlight single lines of code?

This is the listing that I have created. I want to highlight eg. lines 8,9 and 10. Using and escaped \colorbox  didnt work to my expectations because it altered the style of the code making the font smaller thus messing up the alignment of the code.  \begin{lstlisting}[breaklines,caption=Output of disassemble main] (gdb) disassemble  Dump of assembler code for function main: 0x08048344 <main+0>:    lea    0x4(%esp),%ecx 0x08048348 <main+4>:    and    $0xfffffff0,%esp 0x0804834b <main+7>:    pushl  -0x4(%ecx) 0x0804834e <main+10>:   push   %ebp 0x0804834f <main+11>:   mov    %esp,%ebp 0x08048351 <main+13>:   push   %ecx 0x08048352 <main+14>:   sub    $0x10,%esp 0x08048355 <main+17>:   movl   $0x57,-0x10(%ebp) 0x0804835c <main+24>:   movl   $0x3,-0xc(%ebp)} 0x08048363 <main+31>:   mov    -0xc(%ebp),%eax 0x08048366 <main+34>:   add    -0x10(%ebp),%eax 0x08048369 <main+37>:   mov    %eax,-0x8(%ebp) 0x0804836c <main+40>:   mov    $0x0,%eax 0x08048371 <main+45>:   add    $0x10,%esp 0x08048374 <main+48>:   pop    %ecx 0x08048375 <main+49>:   pop    %ebp 0x08048376 <main+50>:   lea    -0x4(%ecx),%esp 0x08048379 <main+53>:   ret     End of assembler dump.   \end{lstlisting}   Is there a package where I can comfortably tell it to highlight some lines  I feed into it ?


Using induction to prove all numbers are prime or a product of primes

Let $n$ and $d$ denote integers. We say that $d$ is a divisor of $n$ if $n = cd$ for some integer $c$. An integer $n$ is called a prime if $n > 1$ and if the only positive divisors of $n$ are $1$ and $n$. Prove, by induction, that every integer $n > 1$ is either a prime or a product of primes.  My try: First, that there's nothing to prove because a number is always a prime or not, so do not what to think. Step:  $P(n): n$ is either a prime or a product of primes. If n=2 then 2 is prime.  $P(n): True$ I want to see $P(n) \rightarrow P(n+1)$ If $n$ is a prime then  $2$ is a divisor of $p+1$, then is a product of primes. If $n$ is a product of primes... I can't say anything about $n+1$.  Some help... please.


What's the context of "performance" or "performances" in this case?

explains the singular and plural of performance depends on the contex.  One person answers that regarding algorithms, it's always singular, but perhaps other people disagreed.  Here's the passage.     In the classical model of computation, the state-of-the-art in   factoring is a composition of four algorithms. Due to their   performance, they are executed in a specific order in the search   for a non-trivial factor of the composite number one wishes to factor.   Should it be "due to their performances"?  What makes it difficult for me in this case is the presence of "their".  So I'm not sure this passage can be put in the singular as Peter Shor .   uses the plural in one case, but that example doesn't clarify what should be done in this case.      In this context, I'm inclined to say it should be singular because the performance of algorithms is in many ways a measure of how successful they are, determining the context, but I'm not sure.  What would you say is the context here of this case?  The text could be written to "Due to their complexity classes, [...]" and then plural would be a necessity.  But I'm in the interested in the question asked, not in how it could be rewritten.


What is the difference in using 'rises' and 'rising'?

I get stuck about using a vert after an object. More specifically, can I use 'rises' instead of 'rising' in the following sentence: "There are 130 of them altogether, each one 'rising' between 20 and 25 meters from the ground to support a frame of iron bars on which the roof originally rested". If it's accepted, please anyone can help me explain the difference when using it. And what are the contexts we should use the verb + ing like about sentences? Thanks in advance.


Using multinom() and glm() functions in R to determine at what extent multiple factorial variables influence the outcome. Get different results

I am analysing data of covid19 patients and trying to determine which illnesses could be detrimental for the outcome. In the original data table there are three possible outcomes - 1 (recovered), 2 (dead) and 3 (transferred to another department). For the binomial regression (glm) I reduced the data frame by filtering out the patients with the 3rd outcome. There are approx. 60 patients with the third outcome out of 230. Almost all the predictors are factorial. When I do the multinomial regression using multinom() the coefficient for a variable x ( the variable is factorial, takes values of 1 / 0) is 1.078e+00 with p-value 1.227e-04. However when I am doing binomial regression using function glm(family = "binomial") for the same variable the coefficient is 21.435 with p-value 7.163e-05. Also, the confidence interval for the coefficient in the binomial model is very wide (approx. 3 - 52). The same goes with the multinomial model, the confidence intervals are 1e+00 - e+01 wide. What could be the problem? Which result is more reliable?


So I was going thru RoR tutorial, installed heroku, heroku toolbelt. I got an error message from Heroku to update to newvest Git for safety reasons. I tried that with installer but heroku version didn't change.  I installed homebrew and tweaked the .bash profile $PATH and changed Git to use /usr/local/bin/git. Original was something like: /usr/bin/  I got some brainer and put gem update on terminal at one point and then inturreped it as I didn't know what was going on.  Problem is know that terminal says either: command not found or No such file or directory || when I try to run something.  Because of that I can't even get the hidden files to show up. What should I do?  EDIT: when I run /bin/echo $PATH I get: /usr/local/heroku/bin EDIT: Almost **** myself when commands very working but I I was able to run /usr/bin/open ~/.bash_profile -a  and comment out export route defined by Heroku   Thank you


Zooming in to a selection of vertices with the period key does not work as expected

I am following through the exercises in BlenderBasics_4thEdition2011.pdf and have gotten to the section on texturing.  The book goes through the creation of a Lighthouse and now I am texturing it.  I want to have a closeup view of the roof of the lighthouse after partitioning it as the lesson describes on page 54.    In order to get a close up view I selected the roof and want to center the screen on the vertices of it so I pressed the Numpad . key.  When I do that the view zooms so that the roof is off the screen.    What am I am doing wrong?    I tried Ray's answer and was able to move the origin but pressing the Numpad . key still did not work.  The centering was still on the bottom of the lighthouse, as if the origin was still there.


I want to sort a description list in an alphabetical order.  \documentclass{article} \begin{document} \begin{description}   \item[bb] \hfill \\ something bb   \item[aa] \hfill \\ something aa   \item[dd] \hfill \\ something dd   \item[cc] \hfill \\ something cc \end{description} \end{document}


I'm trying to show that  $$\tan\frac{\pi}{7}\tan\frac{2\pi}{7}\tan\frac{3\pi}{7}=\sqrt 7$$  My attempt: Since $\tan x=\frac{\sin x}{\cos x} $ so immediately the denominator is recognized as $$\prod_{k=1}^{3}\cos\frac{k\pi}{7}=\frac{1}{2^3}=\frac{1}{8}$$ as known since elementary classes. To tackle with sine product I tried as $\sin(x)=\cos\left(\frac{\pi}{2}-x\right)$. But I fail with this ideas. How do  I deal with $\sin x$ product?


Why not drop $\hbar\omega/2$ from the quantum harmonic oscillator energy?

Since energy can always be shifted by a constant value without changing anything, why do books on quantum mechanics bother carrying the term $\hbar\omega/2$ around?  To be precise, why do we write $H = \hbar\omega(n + \frac{1}{2})$ instead of simply $H = \hbar\omega n$.  Is there any motivation for not immediately dropping the term?


The sums of $3$ and $8$ must give a number greater than $13$

Prove every natural number greater than $13$ can be express as sum of $3$ and $8$ (regardless of order)


Adapting a large crock pot recipe to a smaller crock pot

I've found similar questions, but they have all be very generic. I'm curious about a specific recipe,   It calls for a 5-qt slow cooker, but mine is 2.5 quarts. I want to know if 1.) can I just half the ingredients? 2.) do I also need to half the cooking time?


File name too long when copying to a directory with shorter file path

This is weird.  I have a meanJs installation, the contents of which I copied to another folder.  Original folder path: C:\work\defaults\mean_0.3.3  File contents copied to: C:\work\defaults\a  As you can see it's obvious that the file contents are copied to a folder with a shorter name, so the file name too long error should not come, yet it does.  Is this a windows 10 bug?  Tried to do the it with copy-item command on the powershell and this is part of the output (it goes on for a while):  PS C:\work\defaults> copy-item .\mean_0.3.3\ -destination .\b -recurse copy-item : The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters. At line:1 char:1 + copy-item .\mean_0.3.3\ -destination .\b -recurse + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : WriteError: (test-delayed-http-upload.js:FileInfo) [Copy-Item], PathTooLongException     + FullyQualifiedErrorId : CopyDirectoryInfoItemIOError,Microsoft.PowerShell.Commands.CopyItemCommand  copy-item : The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters. At line:1 char:1 + copy-item .\mean_0.3.3\ -destination .\b -recurse + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : WriteError: (test-delayed-stream-auto-pause.js:FileInfo) [Copy-Item], PathTooLongExceptio    n     + FullyQualifiedErrorId : CopyDirectoryInfoItemIOError,Microsoft.PowerShell.Commands.CopyItemCommand  copy-item : The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters. At line:1 char:1 + copy-item .\mean_0.3.3\ -destination .\b -recurse + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     + CategoryInfo          : WriteError: (test-delayed-stream-pause.js:FileInfo) [Copy-Item], PathTooLongException     + FullyQualifiedErrorId : CopyDirectoryInfoItemIOError,Microsoft.PowerShell.Commands.CopyItemCommand


I own 2 d10 dice with differently numbered sides (0 through 9, and 00 through 90), although the same applies for two identical 'regular' d10 dice.  How do I read the percentage value if I use both dice?  It's pretty straight-forward if I roll between 11 and 89, but outside this range it becomes slightly confusing:  50, 6 → 56%  8, 9 → 89% 00, 0 → 0% or 10% or 100%? 90, 0 → 90% or 100%? 10, 0 → 10% or 20%?   Note: if I roll with identical d10, I roll sequential, not simultaneous to avoid discussion if the 8 or 9 is the first digit.  I have a hunch that 0% isn't really a thing in most systems that use d100, so that eliminates 00, 0 → 0%.  So is it then true that on the first d10, the 00 counts as zero, but on the second d10, the 0 counts as ten?


Oracle:Get Most recent Transaction based on updated Date ad like column

Hi I am trying to get most recent transaction based on updated timestamp along with another column like i i tried with below queries but did not work. Create Table Transactions(Transaction_Id number,User_ID varchar(20),Transaction_Name varchar(20),Upd_Dt Date);  Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(123,'User1','FROM_CUSTOME_ON_0107',to_date('11/26/2013','mm/dd/yyyy')); Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(124,'User1','FROM_CUSTOME_ON_0207',to_date('12/26/2013','mm/dd/yyyy')); Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(125,'User1','FROM_CUSTOME_ON_0207',to_date('01/26/2013','mm/dd/yyyy'));  Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(126,'User1','FROM_CUSTOME_ON',to_date('02/26/2013','mm/dd/yyyy')); Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(127,'User1','FROM_CUSTOME_ON',to_date('03/26/2013','mm/dd/yyyy')); Insert into Transactions(Transaction_Id,User_ID,Transaction_Name,Upd_Dt)values(128,'User1','FROM_CUSTOME_ON',to_date('04/26/2013','mm/dd/yyyy'));  Tried Query: Select tl1.Transaction_Id from Transactions tl1  where tl1.Upd_Dt = (Select max(tl2.Upd_Dt) from Transactions tl2) and tl1.Transaction_Name  like 'FROM_CUSTOME_ON_%';  How to get exact record which LIKE 'FROM_CUSTOME_ON_MMYY'?


How to connect Selenium to an existing browser that was opened manually in java or create semi automated tests?

I want to achieve some use cases in which:  I want to perform some tasks that require manual intervention before kicking in automation execution. For instance, I need to manually launch the browser, navigate to the desired page, perform some manual tasks like entering captcha manually and then run the automation script to continue from there.  Debugging – Let's say we are working on a test script for a certain page (product checkout) in the application. But the script to reach that page (add to cart) is not ready yet. We can manually launch the browser and navigate to that page and then run the automation script.  Can someone help me to achieve this type of scenario?


How can I ask someone if they are male or female politely?

In my daily work I communicate with a lot of people in my company that I have neither encountered in person nor heard them on phone. The conversation is usually e-mail or online chat. Some of them have ambiguous first name. I would like to know if they are male or female so I know if I should refer to them as "he" or "she" when talking to other members of my team (for example explaining conclusion of the communication with the person). Is there a preferred polite way how to ask?


c# assigning different values to an array with random generator

I have two arrays called numbers and sounds. My code is below. When I use random generator, I don't want the same value to be assigned to the sounds array. sounds[0],  sounds[1],  sounds[3] should have different values all the time. Thanks   string[] numbers ={ "1", "2", "3", "4", "5", "6", "7","8","9","10","11","12","13","14","15","16","17","18","19","20"};  Random r= new Random();  sounds[0] = numbers[r.Next(0, numbers.Count())];  sounds[1] = numbers[r.Next(0, numbers.Count())];  sounds[2] = numbers[r.Next(0, numbers.Count())];


How to discard committed changes to just one file?

I have a commit that involves changes to several files. Now I want to remove the changes that I did to one of the files. More precisely, I want this file to be identical to its current version on the remote master. How can I achieve this?  I guess that   git checkout -- <filename>   might do what I need but I am not sure.  I have also seen this syntax:  git checkout <commit> <filename>   I guess that the last command removes the changes of the file introduce by a particular commit but what then the first command does? Does it remove the changes introduced by all commits performed after git pull?


Where can I read the full notification log text

My question is related to , but I do not necessarily need to "show" the full notification text, only to acces its content somehow, for example by finding its source log so I can read it with vim/grep, etc.   I'm missing some critical information because the notification text is truncated.    Where is the macOS log file where I can read all those notifications ?


Windows - how to install one program but have the ability to swap its settings/licenses (container?)

This is an odd one to explain, bear with me.  We have a program, call it Program-A.  We run this program on our Windows machines on behalf of customers, but each customer has their own license for it.  The first time we install it we use Customer-A's license, but instead of un-installing and installing again for Customer-B with their license, it would be good if we could just somehow swap the application settings/licensing/registry etc, especially as we may need to swap between customers many times a day.  I know how the program stores settings/licenses is going to be specific, which is why I'm wondering if there is a generic way of 'containing' an application during an install, like a virtual environment.   To take it one step further, it would be ideal if this 'container' could be stored and copied to any Windows machine - so instead of installing it, we just "run" it and it thinks its already installed.  Update 1: the application we use is run from the command line, so we need to be able to start it by absolute path to the executable.  Update 2: preferably it needs to be open-source/freeware as we don't have a budget for anything right now :(


Do two distinct level sets determine a non-constant complex polynomial?

Let $f$ and $g$ be non-constant complex polynomials in one variable. Let $a\neq b$ be complex numbers and suppose $f^{-1}(a)=g^{-1}(a)$ and $f^{-1}(b)=g^{-1}(b)$. Does this imply $f=g$?  If we think of entire functions instead of polynomials, the answer is negative: take $e^{-z}$ and $e^{z}$ and they share the same level sets for 0 and 1. More generally, Nevanlinna's 5-values theorem says that 5 level sets completely determine a non-constant meromorphic function. Can we lower this number when dealing with polynomials?


What will happen if I use RSA encryption for plaintext larger than RSA bit size?

I have often read that using RSA for encrypting bigger size plaintext is not good solution.  What I understand is that using RSA encrytion is best for small plaintext and most effective if it is smaller than 'bit size' of RSA. For instance, if I use RSA with a 2048 bit size then the plaintext that I can encrypt must be smaller than 256 bytes.  Is this true? What happens if the plaintext is bigger than 256 bytes? Why is there a problem with larger plaintext when performing RSA encryption?


What is the opposite of "parallel" in architecture?

The two towers of the Verrazano Bridge are not parallel: they are slightly [???] to account for the curvature of the earth.    What is that word?


How do I get a black background with flash?

I have a Canon EOS Rebel T5. How can I achieve this using flash? Anytime I take pictures with flash, the background also gets brighter. I really want to put emphasis on the subject and have a dark/black background.


Creating a partition for 14.04 next to XP for dual boot

I was installing 14.04 and the only options I got were replace XP completely or something else. I choose something else. Partitions come up. Problem is I can't figure out how to create a new partition for 14.04 from here. I want to keep XP and install 14.04 as a dual boot option.


I have a singleton that I'd like to keep alive for the lifetime of an .  public final class KeepAlive extends Whatever {     private KeepAlive() {}      private static class Singleton {         private static final KeepAlive instance = new KeepAlive();     } }   Is Singleton.instance considered a strong reference, so that it will not get GC'ed?  UPDATE: Does Android use a custom classloader? Is so, would it ever unload a class like KeepAlive or Singleton?


Hello Im getting the following error when trying to update my database:      Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42S22]: Column not found: 1054 Unknown column ''1'' in 'where clause''   Im getting three variables via POST They are:   a) the Column I want to change   b) The new value for the column  c) the ID which row to change...  Im using PDO, this is my Query with param-binding and execution:  $stmt = $db->prepare('UPDATE `artists` SET `:spalte` = `:wert` WHERE  `id` = `:pk` '); $stmt->bindParam(':spalte', $name); $stmt->bindParam(':wert', $value); $stmt->bindParam(':pk', $pk); $stmt->execute();   I hope someone will understand this error...  Best Regards  Dave


What is the difference between Python's list methods append and extend?

What's the difference between the list methods append() and extend()?


Show $f=g$ for all reals given $f=g$ for all rationals ( epsilon-delta continuity)

Suppose that $f,g:\mathbb{R} \rightarrow \mathbb{R}$ and are both continuous. For all $x \in \mathbb{Q}$, $f(x)=g(x)$. Show $f(x)=g(x)$ everywhere by using the epsilon-delta definition of continuity.  I know we can start off be taking c as a point not in the rationals and writing down what it means for f and g to be cts at this point but so far I can't figure out how to get any further.  Any help would be appreciated.


For $0<b \leq a$ prove that $\frac{1}{8}\left(\frac{(a-b)^2}{a} \right) \leq \frac{a+b}{2}-\sqrt{ab} \leq \frac{1}{8}\left(\frac{(a-b)^2}{b} \right) $

For $0<b \leq a$ prove that $$\frac{1}{8}\left(\frac{(a-b)^2}{a} \right) \leq \frac{a+b}{2}-\sqrt{ab} \leq \frac{1}{8}\left(\frac{(a-b)^2}{b} \right) $$ I was trying compare the following expressions $$\frac{a+b}{2}-\sqrt{ab} =\frac{1}{2}(\sqrt{a}-\sqrt{b})^2$$ $$\frac{1}{8}\left(\frac{(a-b)^2}{a} \right)=\frac{1}{2a}\left(\frac{a-b}{2}\right)^2\leq\frac{1}{a}(a-b)^2$$ and use the fact that $\sqrt{a}  \leq a$ when  $a>0$ but I don´t get good results. Any hint of how I should start?


Does the order of declaration matter in Java/C#?

In C++ I can't use a method if I declare it after the calling method.    Does this order matter in other languages like Java or C#?


Which is correct, a "two-year" program or "two-years" program?  The difference between two expressions is the absence/presence of "s", i.e., singular or plural.


Site name gets cropped while looking at user profiles on international Stack Overflow sites

I can't see the complete 'en español' underneath the Spanish Stack Overflow logo on user profile pages. Nothing changes when I scroll, but when I go to the , the logo gets shifted up a bit and it looks fine. The same thing happens on the  site.  You can tell that the logo is the correct image but shifted downwards because the top of the 'in [language]' text is visible:    I'm on Vivaldi 2.0 for Windows 10 and on Chrome 69.0.3497.100 for Windows 10. It happens only when you don't have an account for that site, both when you're anonymous and when you have connected accounts on other sites.


How do I get through Snowdin on the Genocide run on switch?

I just recently finished a Neutral route because I was trying to do genocide. I killed every monster I came across. When I found out you need to HUNT down every single monster, I tried to, and was doing pretty good until I came to snowdin. There's 3 monsters left, and I can't find a single one. I tried to google it, but all the answers that came up were for the computer. I am on a switch. Can you please help?


"Some settings are managed by your organization" while not on domain?

So, I installed Windows 10 Pro 64-bit yesterday and have been configuring it since.  Somewhere along the way a setting got triggered somehow which results in a message "Some settings are managed by your organization."  I would like to know how to correct this.    I am not part of a domain, this is a home computer and there is one user account, mine, with administrator privileges.


How can I get wget to always download the file, e.g. I don't want "The file is already fully retrieved; nothing to do"

I'm giving a very simple command, such as  wget http://www.example.com/updates/Avail.asp -O avail   Which downloads a very small file containing just a few integers indicating which updates to my app's database are available. My app then looks at the contents of the file to see if any further action is required.  But I keep getting  The file is already fully retrieved; nothing to do.   As near as I can tell, wget is determining that the file exists and is the same size as the one at the remote server, and so skips the transfer. It seems to be ignoring all timestamps.  The problem is, the file probably has changed, but the size remained the same. How can I get wget to download it again?  I have considered doing this:  wget -v http://www.jepptech.com/tfr/Available.asp?UserID=Public -O - > avail   But I'm worried that this will wipe out avail if the transfer fails.  Meta: what are the criteria that wget uses to decide a file has been downloaded? Is it just the file size, as I suspect?    Answering some of the comments:  re: worrying about wiping out avail if the transfer fails -- I'm thinking of the case where the network is down, the remote server doesn't answer, or any number of other cases where the download wouldn't even get started. I'm hoping that in those cases, wget would just leave the file alone.  I did try wget -N ... and it didn't help. I also received this message: WARNING: timestamping does nothing in combination with -O. See the manual for details.  The --no-cache option also did not help. My understanding is that this is a pragma to remote servers telling them not to cache the file. I don't think it tells wget that the local copy should be disregarded.  I considered the possibility that wget was comparing a hash, but I examined the headers coming from the remote server and there's no hash in them. I also tried modifying my local copy slightly to change its hash and it didn't help. I'll wait until I'm sure the file has changed on the server and try again. (Update: the file has changed on the server but wget did not pick it up.)  Re: "Possible duplicate of How to force redownload with wget?", that solution was to use -O - > avail, which I already thought of, but see my previous comments about not wanting to wipe out avail.  Re: "Relevant: How to allow wget to overwrite files" -- yes, I already found that solution. It solves a different problem, but not this one. Although one of the non-accepted answers was to use curl instead, and I think I'm going to go with that route.  Thanks for everybody's input.


Given the following Interfaces:  interface IEntity {     int Id{get;} }   interface IPerson : IEntity {     string Name{get;}      int Age{get;} }  interface ITeacher : IPerson  {     string StaffId{get;} }  interface IStudent : IPerson  {     string StudentId{get;}     string Courses{get;} }  interface IRepository {     T Get<T>(int id) where T : IEntity }   I have the following classes in my namespace  public class EntityBase() : IEntity {     int Id{get;set;} } public class Teacher : EntityBase, ITeacher{} public class Sudent : EntityBase, IStudent{}   Currently I am implementing this IRepository as follows:  class Repository: IRepository {     IDataContext Context{get;set;}      T Get<T>(int id) where T : EntityBase     {         if(typeof(T) == typeof(Teacher))             return Context.Get<ITeacher>(id);         if(typeof(T) == typeof(Sudent))             return Context.Get<ISudent>(id);         throw new Exception("Unknown Interface " + typeof(T).Name);     } }   Is there a betterway of implementing this? Given that our Context has no knowledge of our data types (Teacher, Student), just its interfaces (ITeacher, IStudent).  Can something like this work?  class Repository: IRepository {     T Get<T>(int id) where T : EntityBase     {         var MyInterface = FindInterface<T>();         return Context.Get<MyInterface>(id);     } }


How to include Mathematica code in LaTeX/Beamer

I found the best (IMHO) way to include Mathematica code in LaTeX:  (@jkuczm)  To the test I put the TeX code from link above, but it doesn't work with Beamer presentation. File can't be compiled. I get many errors like this:  Integrate[{y^(-3)*(1-(a/y)^2)^(-2)},{y,r,Infinity}] \end {mmaCell} \begin \ETC. ! Paragraph ended before \FV@BeginScanning was complete.   ! LaTeX Error: \begin{list} on input line 45 ended by \end{beamer@framepauses}.  ! Missing } inserted.  ! Extra }, or forgotten \endgroup.  ! LaTeX Error: \begin{list} on input line 45 ended by \end{beamer@frameslide}.  ! LaTeX Error: \begin{list} on input line 45 ended by \end{document}.  ! You can't use `\end' in internal vertical mode.  ! LaTeX Error: \begin{list} on input line 45 ended by \end{document}.  ! Emergency stop.   Any ideas on how to include Mathematica code in Beamer?  Edit: It was enough to use fragile frame. Thanks for @samcarter


Most of the examples that I see about writing to a FIFO say to use the echo or cat commands and redirect stdout to the file. E.g.,  echo 'a' > /tmp/my_fifo   However, this will create a regular file if the FIFO does not already exist. Is there some analog to mkfifo but for writing that would fail if it doesn't exist? That is, something similar to:  echo 'a' | write-to-existing-file /tmp/my_fifo


Why is it that when you add normally distributed random variables the variance gets larger but in the Central Limit Theorem it gets smaller?

When you add two independent normal distributions the resulting distributions' variance is the sum of the variances i.e. it gets larger.  However, the Central Limit Theorem states that  when independent random variables are added, their properly normalized sum tends toward a normal distribution (informally a bell curve) even if the original variables themselves are not normally distributed.   and also says that as you add more variables the variance gets smaller. Why does the variance increase in one case but decrease in the other? Is it because in the CLT case the random variables come from the same underlying distribution?


Windos 10 Task Manager's Disk percentage suddenly jumps to 100% with no warning; I've already tried all the usual solutions

Good evening; I've been having a problem with the Disk percentage seen in Task Manager, which jumps to 90-100% constantly for no reason. I've already tried to vanilla solutions: disabling Superfetch and Windows Search, clearing the temp folder and virtual memory, changing settings on Chrome and ran an anti-virus. The HDD health checks also say my HDD is healthy. Any idea on what would it be?


Installing from bios with no current os, help

I'm a complete newbie to this, so I'm going to need a full walkthrough with as little jargon as possible. Short story: I bought a used laptop that's in great shape off ebay. Dell Latitude, 16 gb ram, 128 gb ssd, i7-5600u core. Bit old, good heart. However, it has no os, just the bios. How can I get Ubuntu on here with as little fuss as possible? I have only worked with Windows vista, 8, and 10, plus chrome os and I've never had to install an is before. I have access to computers running on chrome os and Windows 10, plus mysterious hard drives my dad left when he died. I also have some flash drives in varying states of functionality, and HDMI cables that were being used to connect my previous laptop to the tv because the screen broke but all else was fine. My dad also left a whole drawer of mysterious cables I don't know the names of. Hope this is enough info, tell me if in my ignorance I left something out. Thanks in advance!


PCB - Altium designer resistor voltage divider calculation

Good evening, I have a problem, I'm not really studying EE or know anything about EE, but I'm doing an optional course in PCB design, in my schematic document, I have a place (picture), where I have this text written next to it:     Calculate voltage divider for 1.8V output voltage   I really have no idea how to do this, and I might find resources how to calculate it, I'm a bit scared I might find a wrong answer. I would like to know for sure, so that's why I asked here.  If anyone could help I'd be happy. Also, if this picture isn't enough to calculate, I can edit and paste a bigger picture of the schematic. Thank you in advance.


working with incredibly large numbers in .NET

I'm trying to work through the problems on  but I keep running into a couple of problems.  The first is a question of storing large quanities of elements in a List<t>. I keep getting OutOfMemoryException's when storing large quantities in the list.  Now I admit I might not be doing these things in the best way but, is there some way of defining how much memory the app can consume?  It usually crashes when I get abour 100,000,000 elements :S  Secondly, some of the questions require the addition of massive numbers. I use ulong data type where I think the number is going to get super big, but I still manage to wrap past the largest supported int and get into negative numbers.  Do you have any tips for working with incredibly large numbers?


How to proceed after clicking a button and that navigates to another page in selenium

Exception in thread "main" org.openqa.selenium.NoSuchElementException: no such element: Unable to locate element: {"method":"xpath","selector":"//input[@name='Name_First']"}


Is it possible to transfer Pokemon from previous 3DS Pokemon games to Sun/Moon?

I own three Pokemon games on 3DS: Y, OmegaRuby and Moon. I've got some nice Pokemon in first two. Is it somehow possible for me to transfer my Pokemon to Pokemon Moon?


Is there any algorithm to represent the given  integers  in the form $N=x^2-ny^2$, $n>1$, say for $n=2$. As we have for any prime, $p$,   a prime $q$ can be written as $q=x^2+py^2$,whenever $q$ is a quadratic residue of $p$ called cornacchia algorithm


Do reroll and dice-adding abilities work on critical hits and critical failures?

Several features like the Lucky feat, the divination school, and bardic inspiration can change the outcome of a roll by adding or changing the result.  The lucky feat states:      You can choose to spend one of your luck points after you roll the   die, but before the outcome is determined.   The divination school states:     You can replace any attack roll, saving throw, or ability check made   by you or a creature that you can see with one of these foretelling   rolls. You must choose to do so before the roll, and you can replace a   roll in this way only once per turn.   And the bardic inspiration states:     The creature can wait until after it rolls the d20 before deciding to   use the Bardic Inspiration die, but must decide before the DM says   whether the roll succeeds ar fails.   My issue is understanding the concept "Before the outcome is determined". Some examples:   Bob rolls a 1 on an attack roll, the outcome is automatically determined, he failed. He can't roll a luck dice, because 1 is a natural failure for an attack. Tim the ogre attacks Bob, and rolls a 20 on the dice. It's a critical and automatic succes. Bob can't spend a luck dice to change Tim's roll, because a 20 is a natural succes.   Bardic inspiration is out of the formula, because modifiers don't change the outcome of an automatic succes or failure.  In the case of the divination school Bob the Wizard can expend those dice when the GM says "the ogre attacks you", Or when Bob decides to attack and choose a foretelling dice.   My question is. Did I get everything right, or I missed something? And, What happens with the divination school feature when you roll behind the DM screen?   Thanks for your answers, and sorry for my english, It isn't my native language.


No password to run command as root for fixed command?

Is it possible to define a rule in sudoers to allow one user to run one well defined command as root, without password or other authentication except being the right user?  Are there alternatives to solve this (or something very similar)?  Use suid permission bit? Maybe make use of ssh keys somehow?


Setting ArcGIS Desktop license to lower level for testing whether Python script still runs?

I have a Python script that will need to be given to a client.   We are currently evaluating what license level the client will need in order to run the script for their software acquisition purposes.   We all have ArcGIS 10.1 Advanced license in our company.   I checked all the tools and extensions used in the script against the web help and found that they should work on the Standard license level.   Is there a way I can test the script against the Standard license level, when we have no Standard license level in or company (only the higher Advanced level)?


Create a PDF from PowerPoint with animations

I have PowerPoint slides with visual effects on them, so each line appears after clicking on the screen in the presentation. When I convert them to PDF the slides are mostly empty and only some titles are in them and the lines that had the visual effect don't appear.  They come out looking like this:    How can I convert them to PDF properly, without having to go through all of the slides (there are like 200 of them) and removing each effect?


Is buying country specific domain and redirecting it to .com domain good for SEO?

I have a website with .com top level domain. I mainly target audience from my country, but the service it offers is not limited to my country. I am thinking of buying the country specific domain name too, and redirecting it to my existing .com domain to improve SEO for searches including my country name. But I am not sure whether this will help or not. Does anyone know whether this will have a positive impact on SEO or not?


Canadian Citizen, but can I leave Canada with a foreign passport?

I am Canadian citizen with an Austrian passport as well. I wish to leave Pearson Airport using only my Austrian passport to live in EU. (I am in Canada a Canadian) Would this be acceptable?


Let $N$ and $N'$ be two sets. Is it possible that $N \subseteq N \times N'$?  I don't think so, but actually I am not able to get any absurd sentences supposing that is true.   Let us suppose that $N \subseteq N \times N'$. Then, for any $x \in N$ there exist $n \in N$, $n' \in N'$, such that $x = (n,n')$. But then there exist $m \in N$, $m' \in N'$, such that $n=(m,m')$, $x=((m,m'),n)$ and so on. I see it is ugly, but I can't understand why it is absurd.


What is the use of a triple male USB cable?

I found a USB cable with three male connectors from somewhere. I'm sorry I don't know what it's called. I've never seen any such cable before. Tried searching on the Internet and many people, couldn't find any answers.  What may be the possible use(s) of this?  A picture of the cable:


removing horizontal bar from fancyhdr header

The following codegenerates a header with an horizontal. How can I get rid of it? Thanks  \documentclass[11pt,a4paper,hidelinks,fleqn]{article} \usepackage{lastpage} \usepackage{fancyhdr} \pagestyle{fancy} \chead{My Header}   Note this question is different from  where the title is misleding, as the author did not want headers at all.