I just installed Ubuntu today and I went to the Ubuntu software center to install Adobe Flash player. And when the install button is pressed, I received the following message:  Package dependencies cannot be resolved This error could be caused by required additional software packages which are missing or not installable. Futhermore there could be a conflict between software packages which are not allowed to be installed at the same time.  Please help me.


How to show the set of all algebraic real number is countable

A real number $x$ is said to be algebraic if there is a nonzero polynomial $p$ with rational coefficients such that $p(x)=0$. Show the set of all algebraic real number is countable.   Let $Z$ be the set of all algebraic real number.  Things I know:  (1)The denumerable union of denumerable sets is denumerable.  (2)A polynomial of degree $n$ has at most $n$ zeros.  (3)$\mathbb{Q}$ is denumerable.  (4)A subset of a denumerable set is denumerable.  Hint, think of the sets:  $A$) set of zeros of a given rational polynomial.  $B$) set of rational polynomials of a given degree.  $C$) set of all rational polynomials.  My thought is that if I can show that $Z\subseteq A\cup B\cup C$ and that $A,B,$ and $C$ are denumerable then I have shown Z is countable.  The set $A$ is clearly finite from (1), therefore denumerable.  Is my logic for the proof sufficient and how can I say $B$ and $C$ are denumerable?


Why is the estimated variance of a random effect not equal to the variance of its BLUP estimates?

I am learning mixed effect model from .  I built a simplified model and trying to extract the $\gamma$ vector from linear mixed effect model   $$y=X\beta+Z\gamma+\epsilon$$  then calculate variance of $\gamma$. (It is a toy model and we only have random effect on intercept, so $\gamma$ is a vector not a matrix)  Why it is not equal to model summary? (model summary shows DID intercept variance is $1.148$, but variance of $\gamma$ is $1.1026$). What I am missing here?  > library(lme4) > dat <-read.csv("http://stats.idre.ucla.edu/stat/data/hdp.csv") > dat=dat[1:100,c("Age","Sex", "DID","mobility")] > m <- lmer(mobility ~ 1 + Age + Sex +  (1 | DID), data = dat) > summary(m)  Linear mixed model fit by REML ['lmerMod'] Formula: mobility ~ 1 + Age + Sex + (1 | DID)    Data: dat  REML criterion at convergence: 228.5  Scaled residuals:      Min      1Q  Median      3Q     Max  -3.3152 -0.4710 -0.0252  0.9330  1.7854   Random effects:  Groups   Name        Variance Std.Dev.  DID      (Intercept) 1.1480   1.0714    Residual             0.4532   0.6732   Number of obs: 100, groups:  DID, 5  Fixed effects:             Estimate Std. Error t value (Intercept)  3.28826    0.76484   4.299 Age          0.01235    0.01178   1.048 Sexmale     -0.09126    0.14836  -0.615  Correlation of Fixed Effects:         (Intr) Age    Age     -0.766        Sexmale -0.097  0.030  > var(as.numeric(getME(m, "b"))) [1] 1.102682


Does mass as a measure of inertia have a meaning in zero gravity?

Mass apart from the amount of material, is also a measure of the inertia of an object, ie. the resistance to change its motion. In zero gravity, does still mass count as the amount of inertia? In other words, the resistance to move a rock is the same in zero gravity and on earth, if there is no friction etc?


I'm studying a chapter about atomic physics right now but there's thing I just don't seem to understand. When stimulated emission occurs, there's an incoming photon which stimulates the atom to go an energy level lower with the result that a new photon gets emitted.  Can someone explain the reason why the incoming photon stimulates the atom to emit a second one? To me it seemed more logic for the atom to absorb the photon and go an energy level up. There seems to be a phenomenon which I don't know about.


How can I plan server hardware capacity for a project

I want to learn that how How can I plan server hardware capacity by a project. But I need scientifically and    provable solution for this planning.   For example I have a project. That has 1000 unique users, 20 database tables, Used java programming language, etc. These are parameters of projects. But my process may be long running or database selection response. So I will use these parameters and get a result like this: You need 4 Core 2.4 Ghz CPU, 8GB Ram, 100Gb hdd etc.  Is there any way to do this plan?


How can I hover over icons in Ubuntu Dock to see all windows of one application?

I'm using Ubuntu 17.10 with GNOME 3. How can I show all open windows of a certain application using the sidebar (aka Ubuntu Dock)? Right now I have to right-click and select "all windows" to see my other open windows.   Is there a quicker way to do this?


Constructing a Bijective function via an injective and surjective one.

Suppose that $\;f_1,\;f_2:\;A\to B$ such that $f_1$ is injective and $f_2$ is surjective.   I was trying to find out whether there exists $f_3:\;A\to B$ such that $f_3$ is bijective. Is it possible to construct it from $f_1$ and $f_2$?  I tried proving the statement non-constructively via a cardinality argument, but ended up hand-waving a lot (i.e., since the cardinality is the same, there exists a bijection, a bit of circular reasoning). But, I'd be more interested in a construction based argument, as I can't think of one.


Ring of matrices has no nontrivial ideals

It is a theorem that a commutative ring is a field if and only if it has no nontrivial ideals. Clearly this does not hold in the noncommutative case. I am trying to show for instance that the ring of $n $ x $n$ matrices in a given field has no nontrivial ideals despite it not being a field. Now this is the part I am not completely sure about. My understanding is that the kernel of a ring homomorphsim is an ideal and viceversa, every ideal of a ring is the kernel of some ring homomorphsim. So my approach has been to show that there are no homomorphisms in the ring of matrices that do not have a nontrivial kernel. However I am stuck on this step. Any thoughts?


Is it ok to run 2 NM-B cables in 1 EMT protective conduit in an unfinished basement?

I would like to add 3 new 20 Amps outlets in my unfinished basement. I'm going to run some NM-B cable along the ceiling joists and I will use metal boxes attached on the concrete walls as well as use EMT conduit to protect the cable from the receptacle to the ceiling.  If I decide to cable my receptacles in a row using the terminal screws (vs pig tail), can I run the 2 cables from the middle outlet in the same conduit or do I need to run 2 conduits? If yes is there a minimum acceptable diameter to do so?


What books, journals, and electronic resources are most valuable for expanding knowledge of GIS?

What books, journals, and/or electronic resources have you found most valuable for expanding your knowledge in the GIS field, and why?


I'm currently runing Ubuntu 15.04, and I would love to be able to put a video file (currently in webm format, but can be converted if neccesary) as my wallpaper. I am in love with the DreamScene feature Microsoft introduced (then brutally murdered) and i would love to have it on my Linux-Powered PC. If it's for any help, it's  wallpaper.  I've already seen a lot of questions about how to put a video file as a wallpaper on ubuntu, but the answers were all outdated. therefore im asking it again for Ubuntu 15.04


Get list of table names in oracle from information schema

I am using the following query in MySQL and POSTGRESQL.  MySQL SELECT table_name FROM information_schema.tables where table_schema='SmartHome' and table_name like '%House%'  POSTGRESQL. SELECT table_name FROM information_schema.tables where table_schema='public' and table_name like '%House%'.  I want to know equivalent query in Oracle DB.


I would like to get opinions or suggestions regarding embedded databases in Java. In particular I was looking at H2, HSQLDB and Derby. Have you use any of these in a production project? Do you have comment or recommendations to select one over the others?  Thanks  Edit: I am currently evaluating these options to use in our internal developments, so I don't have a specific use case in mind. One of the possible uses I am evaluating them for is a desktop application that uses the database as a local repository. At some point it synchronizes with a central repository (in this case DB2). It is a store and forward architecture. Anyway, this is just a possibility to guide your answers, Basically I’m looking for your experiences using these tools.


A new contact should be added to the top or to the bottom of the contact list?

If you have a contact list, and add a contact to that list, where should the icon of the new contact be added: to the top or the bottom of the list?  The contact list does not follow an exact order, its just data.


Suppose $X$ is infinite and $A$ is a finite subset of $X$. Then $X$ and $X \setminus A$ are equinumerous

Suppose that $X$ is infinite and that $A$ is a finite subset of $X$. Then $X$ and $X \setminus A$ are equinumerous.     My attempt:  Let $|A|=n$. We will prove by induction on n. It's clear that the the theorem is trivially true for $n=0$. Assume the theorem is true for all $n=k$. For $n=k+1$, then $|A \setminus \{a\}|=k$ for some $a \in A$. Thus $X \setminus (A \setminus \{a\}) \sim X$ by inductive hypothesis, or $(X \cap \{a\}) \cup (X \setminus A) \sim X$, or $\{a\} \cup (X \setminus A) \sim X$. We have $\{a\} \cup (X \setminus A) \sim X \setminus A$ since the theorem is true for $n=1$. Hence $X \setminus A \sim \{a\} \cup (X \setminus A) \sim X$. Thus $X \setminus A \sim X$. This completes the proof.       Does this proof look fine or contain gaps? Do you have suggestions? Many thanks for your dedicated help!     Update: Here I prove that the theorem is true for $n=1$.  Assume that $A = \{a\}$ and consequently $X \setminus A= X \setminus\{a\}$. It's clear that $|X \setminus A| \le |X|$. Next we prove that $|X| \le |X \setminus A|$. Since $X$ is infinite, there exists $B \subsetneq X$ such that $B \sim X$ (Here we assume Axiom of Countable Choice). Thus $|X|=|B|$. There are only two possible cases.   $a \in X \setminus B$   Then $B \subseteq X \setminus \{a\}=X \setminus A$ and consequently $|X|=|B| \le |X \setminus A|$. Thus $|X| \le |X \setminus A|$ and $|X \setminus A| \le |X|$. By Schröder–Bernstein theorem, we have $|X \setminus A| = |X|$. It follows that $X \setminus A \sim X$.   $a \in B$.   Let $b \in X \setminus B$. We define a bijection $f:X \setminus \{a\} \to X \setminus \{b\}$ by $f(x)= x$ for all $x \in X \setminus \{a,b\}$ and $f(b)=a$. Thus $X \setminus \{a\} \sim X \setminus \{b\}$. Since $b \in X \setminus B$, it follows from Case 1 that $X \setminus \{b\} \sim X$. Hence $X \setminus \{a\} \sim X \setminus \{b\} \sim X$. Thus $X \setminus \{a\} = X \setminus A \sim X$.  To sum up, $X \setminus A \sim X$ for all $|A|=1$.


Add A Redirect Link In Webform Submit Button

I want to add a redirect link on Webform submission button when a user submit a webform I want to redirect them in different page.  How can I redirect a user after they submit the webform ?


I'm trying to install Ubuntu 17.10 on a HP laptop (Model:HP14bs547TU) as dual boot with Windows 10. Every time installation fails at the grub installation stage. It is giving me the following message     The 'grub-efi-amd64-signed' package failed to install into /target/. Without the GRUB boot loader, the installed system will not boot.   I've never faced this kind of issue previously. How can I overcome it? Please help.  Thanks in advance.


Java - pass key-value params into function with shortest syntax

I want to pass list of key-values pairs into my function.  I can do this by following:  HashMap<String, String> params = new HashMap<>(); params.put("param1", value1); params.put("param2", value2); foo(params);   But there are 4 lines of code. And my foo function will be called in many times in my code, so it becomes hard to read.  Can we decrease number of lines in this call?   Is there a way to write foo([("param1", value1), ("param2", value2)])? Maybe Java standard classes have constructors to pass there several elements? Or can we write some factory class, that will create HashMap in less lines of code?


Can Heat Transfer occur between two bodies with the same temperature but different states only through Latent Heat Transfer?

I understand that temperature difference is the driving force for heat transfer but I have been wondering whether there would be any heat transfer, let's say if steam at 100 degree Celsius and water at 100 degree Celsius are passed through the two sides of a Heat Exchanger.


How is it that Christmas and Easter are celebrated and observed at Hogwarts? The films depict both holidays but no Wiccan feast days are mentioned. Christianity has been intolerant of witches and wizards, the Vatican has been rather negative on Rowlings' Harry Potter series, but the movies seem to depict an armistice or acceptance of conflicting positions. Is the history of the Church's persecution just water under the bridge?


Good day everyone I do not understand why i can't access the file on my flash drive. I edited the said file less than 2 minutes, saved it, made sure to click the unmount button and restarted my computer (i learned to click the unmount the hard way). Now when i tried to access the file its giving me the following error: Unexpected error: Error reading from file: Input/output error  when i try to copy it to another location on the drive i get the following Error opening file '/media/ubuntu/Drive Name/New Folder/file name': Read-only file system  When i copy the file to the desktop i get the following: Error splicing file: Input/output error  But when i am able to open the file and a SIGNIFICANT AMOUNT of detail is missing. about 6 months worth of detail. Please i must recover the full amount of details in that document. Since i added info and saved it under that same name, will disk carving be of any help?  Thank you very much


Why do English speakers say "penny LANE" (emphasis on LANE) but would say "PENNY street" (emphasis on PENNY)?


Can I directly contact another player in clash of clans?

I have a friend who is frequently depressed and about a week ago he left the clan. He doesn’t have any other form of contact, and yeah it’s weird, but I’ve already tried everything in my power. I’m really worried and he has seemingly gone inactive with no warning. Please help me and if I can send him an email somehow that would help me so greatly. Please, he needs help and so do I. Thank you!


Javascript Number Method not returns expected value

I have tried JavaScript Number method and it returns unexpected results.  If i pass 192000000000000005 value into Number() method. It returns 192000000000000000, without 5.   If I Pass 19200000000000005 value, it returns 19200000000000004, which is unexpected.   What is that meaning of those results?  You can find the below screenshot too.  Chrome Console:


Deleting array elements in JavaScript - delete vs splice

What is the difference between using  on the array element as opposed to using ?   For example:  myArray = ['a', 'b', 'c', 'd'];  delete myArray[1]; //  or myArray.splice (1, 1);   Why even have the splice method if I can delete array elements like I can with objects?


Does $\sum_{n=3}^\infty \frac {1}{(\log n)^{\log(\log(n)}}$ converge?

Does the following series converge:  $$\sum_{n=3}^\infty \frac {1}{(\log n)^{\log(\log(n)}}$$  I've tried all test I know... Any ideas ?


I would like to know if there is a difference in the following sentence depending on the preposition. Both seem to be correct. I saw a celebrity while I was shopping in/on Oxford St. Thank you!


Find the differential equation of all circles of radius a

Can someone please post a detailed step-by-step procedure. Given the circle with a radius a, what is the differential equation of the circle.


Is it sloppy to use Exit Function keyword?

In my subs, I usually perform several forms of validation before proceeding with the sub. Is it a bad habit to exit the sub? For example:  Private Sub mySub()      if Not Validated() then         exit sub     end if     'do stuff End sub   Would it be better to enclose the entire body in an If-Then statement?   private sub mySub()     if validated then        'do stuff      end if end sub


What does the Wand of Wonder mean when it says "as if you had cast" vs. "you cast"?

One of the possible effects of the  magic item is (emphasis mine):  You enlarge the target as if you had cast enlarge/reduce. If the target can't be affected by the spell, or if you didn't target a creature, you become the target.  There are multiple possible effects for the wand of wonder that use a similar wording. There are also many possible effects for the wand that say instead that "you cast [spell]". Mechanically, what are the differences between the two wordings (if any)? What exact aspects of the spellcasting process/effects are different between the two?


I'm running Kubuntu 14.04 and my trash folder won't accept any files larger than a text document. Yes, the trash is empty.  I've checked all the related threads here, as well as played with the size settings for the Trash folder in Dolphin, and I've spent a couple of hours on Google trying to find alternative solutions. All I've come up with so far is that this seems to be a somewhat Kubuntu-specific problem, and it's a real pain to resolve. Any ideas or should I just upgrade to v15.10 and hope for the best?


Show that two numbers divided by their GCD are coprime

Let $a, b \in \mathbb{Z} \setminus \{0\}$ and $d = \gcd(a, b)$. Show that $gcd(\frac{a}{d}, \frac{b}{d}) = 1$. I tried proving this by contradiction and showing that otherwise $d$ isn't the gcd of $a$ and $b$, but it didn't work. Could someone please give me a hint on what the proof should look like?


When are 'near', 'near by' and 'nearby' used?

I have read on other fora that 'nearby' is always one word, yet Bill Bryson, the famous travel writer, exclusively writes 'near by'.


Building an executable out if a single cpp file

I know there are similar posts, but I feel like my questions are specific enough to still ask them. Let's say I opt to build an executable by putting actual definitions in header files, and then just including them all in a single cpp file.  If I understand correctly, the implications of that only affect the build process, i.e. compilation and linkage, and have no impact on runtime performance. Is it true?  Moreover, compilation times should be higher, while linking times should be lower. Shouldn't that even it out? And if it doesn't, are increased compilation times truly the only reason nobody builds an application like that?


If I try to compile this example document \documentclass{beamer} \begin{document}  \begin{frame}{Test}   Test \end{frame}  \end{document}  with htlatex temp.tex I get the output: l.34951 --- TeX4ht warning --- \Configure{frametitle}? ---  ! LaTeX Error: Missing \begin{document} in `'.  See the LaTeX manual or LaTeX Companion for explanation. Type  H <return>  for immediate help.  ...                                                                                l.34952 ...i \EndP \HCode{
}                                                   \bgroup ?  ! Emergency stop.  ...                                                                                l.34952 ...i \EndP \HCode{
}                                                   \bgroup No pages of output.  Full log can be found


Risks of disproportionate numbers of training examples for different classes?

fairly new to machine learning so please be gentle!  I was wondering what the risks might be if I have significantly more examples for one class than the other when training a 2-D perceptron; for example, if I have 500 examples of C1 versus 1000 examples of C2, assuming that they are drawn from the same random distribution. In other words, if I have significantly more examples of one class than the other, even though they're from the same distribution and have equal probability of being drawn, doesn't this break the assumption that they're identically drawn and distributed? Are there any other risks I should be aware of?


Can I see how many unique IP addresses visited from one of my links?

I shared a link to a question with a couple of co-workers.  A while later I got a badge for being an "announcer".  This caused me to look up the badge and I found there is also a badge for being a "booster" if it gets to 300 unique IP address views in 4 days.    Is there a quick way to see how many visits one of my links generate anytime I pass it around?


Forms inside a form with conflicting form actions

first time as an OP here. problem: Having an issue with the first upload form(code below its under  the third field set). It ignores the set action = "uploads.php" code bit and when you click the UPLOAD CV button it runs the sent.php code instead of its own. PS there are no errors codes when the code is run, Would sincerely appreciate the assist. attempts to fix: Tried to switch same result, run code through debuggers no errors detected, changed the submit buttons from  to  code:` <form id="msform" action="sent.php" method="post">

Apply for position

Personal informatiion

Upload Documents

    <fieldset>
Apply for position

Provide information as promted below.
     <input type="text" name="username" placeholder="Name in full" />     <input type="text" name="worktype" placeholder="Attatchment/Internship"/>     <input type="text" name="email" placeholder="Email"/>     <input type="text" name="phone" placeholder="Phone number"/>     <input type="button" name="next" class="next action-button" value="Next"/>   </fieldset>    <fieldset>
Personal Information

More about you.
     <input type="text" name="Gender" placeholder="Gender"/>     <input type="text" name="Ethnicity" placeholder="Ethnicity"/>     <input type="text" name="Institution" placeholder="Institution"/>     <input type="text" name="Course" placeholder="course"/>     <input type="button" name="previous" class="previous action-button" value="Previous"/>     <input type="button" name="next" class="next action-button" value="Next"/>   </fieldset>  <fieldset>
Upload documents

Provide your cv and Application documents in word and pdf, format respectively.
        <form action="uploads.php" method="POST" enctype="multipart/form-data">
           <input type="file" name="file">           <button type="submit" name="submit">UPLOAD CV</button>
       </form>

       <form action="upload.php" method="POST" enctype="multipart/form-data">
           <input type="file" name="file">           <button type="submit" name="submit">UPLOAD DOCUMENTS</button>
       </form>

 <button name="previous"> Previous </button> <button type="submit" name="submit">Submit</button> </fieldset> </form>`


As you can see I made ChildObject (sphere) a child of ParentObject (arrow), and in object data of the ParentObject I set Duplication/Verts.  That's looking ok to me, but I would like to edit one of "duplicated" spheres. I can not do this right now, because as far as I know I can edit only the ChildObject which will effect all other duplicated spheres, and I don't want that.  How to apply duplication?  And also how can I render only duplicated spheres? In current situation I have to render ChildObject in order to render duplitates of ChildObject, but I don't want to render that one out of order sphere, I just want spheres in shape of the arrow...  Please Help!


virtualbox not working on ubuntu 12.04 64-bit?

I'm new to linux please help ,Every time i try to start up virtual box this pops up:  Failed to open a session for the virtual machine pc. The virtual machine 'pc' has terminated unexpectedly during startup with exit code 1.  Result Code: NS_ERROR_FAILURE (0x80004005) Component:  Machine Interface:  IMachine {22781af3-1c96-4126-9edf-67a020e0e858}


Is there a modified version of Ubuntu that I can choose to load to RAM on start up? Kinda like the LiveCD, but that can be easily modified (ie: I can install stuff) when I choose to boot from disk.  The idea is to install it to a USB drive. I know there's  but slax is lacking in many departments. A "full" version Ubuntu would be better.  A LiveUSB installation seems to be pretty close to what I want, but apparently I have to choose whether or not it will be persistent by the time I install it. I want to be able to choose that every time I boot.


Getting somewhat subjective advice about software development

I know this isn't allowed on Stack Overflow, but I was hoping there was a section on Stack Exchange that would allow this question.  I just need advice for my future career: Currently I'm enrolled in a computer science degree, and I'm not sure what to do next without wasting time. For example, I wanted to learn to make a website (HTML, JavaScript, and CSS) and create a game app (Java, Android SDK) as well as a desktop game (C++).  So basically I wanted to know if I should bother learning all of it, or focus on one thing and what do companies look for in employees. Where can I get this kind of advice (among other questions like this)?


How to easily write the transpose of a matrix?

I have a matrix A, described using an environment bmatrix as in the MWE below.    \documentclass{article}  \begin{document} Consider the matrix  $A=\begin{bmatrix}  1 & 0 & -1 \\  2 & 3 & 1  \\   \end{bmatrix}$  Then its transpose is  $A^T=\begin{bmatrix}  1 & 2 \\ 0 & 3\\  -1 & 1  \\   \end{bmatrix}$  \end{document}   How can I get the transpose of A without typing all its entries? In other word, is there an environment where \ means "end of column" instead of "end of row"?  I hope I could just paste and copy the definition of A and then change bmatrix to vbmatrix or whatever.


Is this possible to use $.getScript in firefox extension.When i am calling it from html it is working but from Js file not able to execute


Is there a way to log or intercept First Chance Exceptions

Short of using a profiler, is there any way inside a running program to detect first chance exceptions?  Ideally, I would like to record more detailed state information that is not available once the catch block has taken over the final exception.


how can I make content from a plugin hidden when user is logged in?

I would like to make my social icons at the top of my page disappear when a user logs in to my website...  what is the best way to go about this and can you give me all options that are possible  please visit :   you will see the social icons at the top


Match text including a line break with re

I have a Python code that parses a text file and finds instances of the words within a tag @(my word). To do this I use, e.g.,: import re  DEF_RE = r"(@\()(?P<text>.+?)\)"  sometext = "find the @(tagged text)."  m = re.search(DEF_RE, sometext)  print(m.group("text")) tagged text  However, if the file contains the tagged text split over two lines the above method doesn't work, e.g., sometext = "find the @(tagged\ntext)."  m = re.search(DEF_RE, sometext)  print(m) None  Is there are way to change my regular expression string to allow the text to be split over a line?


In general inference, why orthogonal parameters are useful, and why is it worth trying to find a new parametrization that makes the parameters orthogonal ?   I have seen some textbook examples, not so many, and would be interested in more concrete examples and/or motivation.


Stolen passport in USA, foreign national needs to fly domestic

To begin with, I am aware that various iterations of this question have been asked, so I will be specific to my case since I feel there may be some differences.  I am on a temporary Visa in the United states, My Passport was stolen when someone broke into my car. Fortunately I am carrying my original Driving License issued in India. I have my work ID, and can print my bank statements out.  I have reported the case with the Police, have a copy of the report, have spoken to my consulate. They will issue a one time travel permit to me ONLY one month before the date of travel ONLY when I show them my ticket. I am set to depart 50 days from now so that doesnt help in getting an ID. So for the time being I do not have an ID on me issues by the consulate, nor my VISA. I have scanned color print outs of passport and VISA, my date of arrival and the date of VISA expiry.  Am I expected to face any issues if I am to board a flight to travel domestically? I am here on a business trip and need to travel within the United states.   I have spoken to the TSA, one of the people I spoke to was positive that I can go through.  However the reason I write this is the second person: She was equally sure that I will not be let through unless I have a piece of paper signed by my consulate with a photo on it.  Any help on this? I dont want some thief to effect my plans here, which I made months ago, and have considerable interests in!!


Is using an underscore as a space in @user_name a valid practice?

Is using an underscore in user mentions as a replacement for a space a valid practice, and if not, then why? It feels obvious for me to do so, however the help on using @username does not say anything about this.


elegant way to sync file between local machine and server (in real time)

I am looking for a "local Dropbox" to sync files between local and server. For complex reason I couldn't install Dropbox on the server. I thought about  but it doesn't work bi-directionally.  After researching a bit, my current solution is: having Dropbox running on local machine, and  with some  deployed on the server. This is the best "local Dropbox" I could build without spending huge effort.  It works but with a bit high maintenance plus it crushes sometimes, so I'm looking for a simple and stable solution to sync file between local and server, bi-directionally. Consider speed and efficiency not a problem, 10X sync time compared with dropbox is acceptable (in LAN environment).  note: git is not an option as I would sync git repository and sometime media files between machines.


How to make ‘blender file view’ support selecting multiple files?

I want to make a script that can import multiple pictures at once in the node editor. But the current file view can only support the import of a single file. How can you make it support multiple files?  import bpy import os  from bpy.props import StringProperty, BoolProperty from bpy_extras.io_utils import ImportHelper from bpy.types import Operator   class OT_TestOpenFilebrowser(Operator, ImportHelper):     bl_idname = 'test.open_filebrower'     bl_label = 'Open the file brower(yay)'      filter_glob: StringProperty(         default='*.jpg;*.jpeg;*.png;*.tif;*.bmp',         options={'HIDDEN'}     )      some_boolean: BoolProperty(         name = 'Do a thing',         description= 'Do a thing with',         default= True,     )      def execute(self, context):         filename, extension = os.path.split(self.filepath)          print('selected file', self.filepath)         print('file name', filename)                  bpy.ops.node.add_file(filepath = self.filepath)          return {'FINISHED'}  def register():     bpy.utils.register_class(OT_TestOpenFilebrowser) def unregister():     bpy.utils.unregister_class(OT_TestOpenFilebrowser)  if __name__ == '__main__':     register()


When I boot my Windows 8 laptop (see details below), it displays this message:  Recovery  Your PC needs to be repaired  A required device isn't connected or can't be accessed.  Error code: 0xc0000225  [ A text saying I should use recovery tools on my installation media to fix the issue. ]  Press Enter to try again  Press F8 for Start-up Settings  Press Esc for UEFI Firmware Settings   If I press Enter or F8, the central part of the message changes to:  The application or operating system couldn't be loaded because a required file is missing or contains errors.  File: \Windows\system32\winload.efi  Error code: 0xc0000225   I don't have a recovery disk and I have owned this computer for a year with no problems. All I did prior to this error was unistall avast and restart. I can only access UEFI Firmware Settings and have no clue what to do from there. PLEASE HELP!


I'm experiencing an annoying problem with a table named SysMessages in one of our databases. When I run a select statement I don't get the contents of this table, but of the sys.sysmessages view in the master database. A use [DBNAME] doesn't help, nor select * from [DBNAME].dbo.SysMessages.  I'm in the middle of a migration to a newer SQL Server version. In SQL Server 2008 R2 I didn't encounter this problem with this database, but in SQL Server 2016 I'm not able to query my own SysMessages table.  Any help would be greatly appreciated.


I'm interested in buying an . What about using Ubuntu on it?  Does it work well?  Can I buy it with Windows 10 and install Ubuntu on first use?


Bounties exist to promote questions. Yet, only one bounty can be active at a time. This request outlines how we might implement having multiple bounties active at a time. Changes are as follows:    So here's what bounties look like currently.    And here's an absolutely wonderful  photoshopped example of how I think we could modify bounties to allow multiple users to separately award bounties to a question.  Now, I know this idea . I'd like to clarify how this question is different:   The referenced question proposes making a bounty 'pool'. I'm proposing making a list of bounties. The accepted answer to the above question was "This idea has issues with awards and it says no in the blog."   Edit: As it seems that this idea has gotten pushback, I've modified the question into a Discussion question and would like to know why it's a bad idea beyond simply that "The blog says no."


I have to redirect www.example.com/docs/....pdf to trader.example.com/docs/....pdf on an existing Project. The same applies to *.biz.  I have no Idea how can i extract the wwww-Part from $host-Variable.  server {         listen 80;         server_name www.example.com www.example.biz;          location /docs {                         root /data/http/example/docs;                         rewrite ^ $scheme://trader.$host$request_uri;         } }   Does anyone have any idea how I can solve this?


Python Regex pattern not finding what I expect

I am trying to extract a date from a string using regex in Python 3 (using Anaconda & Jupyter Notebooks on Win10).  This seems like a simple task but the pattern I'm trying to find doesn't seem to want to extract the date properly using the string that I need to work with.  The pattern appears to work properly for other strings however.  Here's my code:  # Trying to extract this text sequence from the test string: 'April 2, 2020 at 12:30PM'. import re  test = 'Hampden\n \nUnknown\n \nYes\n \nFemale\n \n30s\n \nSuffolk\n \nYes\n \nYes\n  \n\nPAGE2\nMASSACHUSETTS DEPARTMENT OF PUBLIC HEALTH\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n  \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \nData are cumulative and current as of  \nApril \n2\n, 2020 at 12:30PM.\n \n*Other commercial and clinical laboratories continue to come on  line. As laboratory testing results are \nprocessed and the source verified, they will be integrated  into this daily report\n.\n \nL\naboratory\n \nTotal\n \nPatients \nPositive\n \nTotal Patients  Tested\n \nMA State Public Health Laboratory\n \n912\n \n7355\n \nARUP\n \nLaboratories\n \n17\n  \n187\n \nBaystate Medical Center\n \n5\n \n12\n \nBedford \nResearch Foundation\n \n30\n \n219\n  \nBeth Israel Deaconess Medical Center\n \n686\n \n3976\n \nBioReference Laboratories\n \n9\n \n43\n  \nBoston Medical Center\n \n236\n \n647\n \nBROAD Institute CRSP\n \n348\n \n1784\n \nCenters for  Disease Control and Prevention\n \n1\n \n11\n \n\n \n11\n \n195\n \nGenesys Diagnostics\n \n106\n  \n145\n \nLabCorp\n \n715\n \n4836\n \nMayo Clinic Labs\n \n353\n \n1812\n \nPartners Healthcare\n  \n740\n \n4112\n \nQuest Laboratories\n \n4161\n \n27606\n \nSouth Shore Hospital\n \n7\n \n34\n  \nTufts Medical Center\n \n463\n \n2154\n \nUMASS Memorial Medical Center\n \n32\n \n163\n  \nViracor\n \n80\n \n1150\n \nOther\n \n54\n \n167\n \nTotal\n \nPatients Tested*\n \n8966\n  \n56608\n \n'  newtest = test.replace("\n", "") result1 = re.findall(r"Data are cumulative and current as of (.+)\.", newtest, re.IGNORECASE) print(result1)  # This returns "April 2, 2020 at 12:30PM. *Other commercial and clinical laboratories continue to  # come on line. As  # laboratory testing results are processed and the source verified, they will be integrated into this  # daily report". # Why does it not find the . after the PM and stop extracting?  # When I attempt to run the pattern again on result1, again, it doesn't seem to find the . after the  # PM (it extracts until the next period) and # returns: "April 2, 2020 at 12:30PM. *Other commercial and clinical laboratories continue to come on  # line". # What is special about that . after PM that keeps regex from seeing it??? result2 = re.findall(r"(.+)\.", result1[0], re.IGNORECASE) print(result2)  # If I use the same pattern on a subset of the test string, it sees the . after the PM and returns # the correct result.  Why??? subtest = 'Data are cumulative and current as of April 2, 2020 at 12:30PM. *Other commercial' result3 = re.findall(r"Data are cumulative and current as of (.+)\.", subtest, re.IGNORECASE) print(result3)   I'm guessing I must be doing something stupid but I haven't been able to figure out what it is.  Can anyone provide some guidance?  I could change the pattern to this (r"Data are cumulative and current as of (.+[P|A]M)") and it works properly on all strings but would still like to know why it seems to be having problems seeing the . after the PM.  Appreciate any help.


How to calculate left/right oriented angle between two 2D vectors?

I would like to calculate angle between two 2D vectors. Here's a picture of what I'm trying to achieve:    I have an obstacle line segment AB and incoming moving PC. If I'm coming from one side C¹D¹ and angle ⍺ < π/2 (i.e. right side) then PC will turn left. On the other hand if ⍺ > π/2 then PC will turn right. But if PC will come from the other side C²D² it should work as well for angle β as per picture.  So what I need is to determine whether the angle between AB and CD is larger to the left or right basically.  I've tried these things, while having vectors defined as:  Vector2 ab = Vector2.Normalize(new Vector2(b.x - a.x, b.y - a.y)); Vector2 cd = Vector2.Normalize(direction);   1) To calculate angle using atan2, but it works only randomly (1/4 of cases).  Single angle = Math.Atan2(cd.Y, cd.X) - Math.Atan2(ab.Y, ab.X);  if (angle > MathUtil.PiOverTwo) {     RotateRight(); } else if (angle < MathUtil.PiOverTwo) {     RotateLeft(); }   2) To use normals somehow. This works a bit better but only from one side I think. (1/2 of cases, better but not there)  Vector2 normal1 = Vector2.Normalize(new Vector2(-ab.Y, ab.X)); Vector2 normal2 = Vector2.Normalize(new Vector2(ab.Y, -ab.X)); Double angle1 = Math.Atan2(normal1.Y, normal1.X) - Math.Atan2(cd.Y, cd.X); Double angle2 = Math.Atan2(normal2.Y, normal2.X) - Math.Atan2(cd.Y, cd.X);  if (angle1 > angle2) {     RotateRight(); } else if (angle1 < angle2) {     RotateLeft(); }


Counting points in shapefile within polygons of another shapefile using ArcGIS Desktop?

I'm creating a map with two shapefiles:   A polygon of counties Points of cities   I used the function Intersect to group the cities in each county.  I'm trying to get the number of cities in each county to show up in the legend.    For example, in county A there are 16 cities, in county B there are 7 cities and so on.  I'm trying to create a choropleth map that shows the number of cities in each county.


Two entities with the same name in differents packages

I have two entities with the same name (but in differents packages) in my project, that cause an exception :  Use of the same entity name twice: MyEntity   duplicate import: MyEntity refers to both packageOne.MyEntity and packageTwo.MyEntity (try using auto-import="false")   I tried to set the property auto-import to false in my persistence.xml, but it doesn't change anything :  <property name="hibernate.auto-import"  value="false"/>   Is there another solution than add a name in the Entity annotation   @Entity(name="MyEntity_One") @Entity(name="MyEntity_Two")   ?


Perform Linq Orderby generic list contain integer and string value

In my generic list contain integer and string value. how do i perform OrderBy or OrderByDescending.  For example    List<String> codelst = new List<string>() { "1","2","3","4","5","10","100","a12","b12" };   codelst.OrderBy(g => g);   It shows like as follows  1     10   100     2     3     5      a12     b12   but need to show  1         2     3     5     10   100   a12    b12   if I have convert to int it shows input string error  codelst.OrderBy(g => Convert.ToInt32(g));   How to achieve this


jQuery using multiple buttons of the same class to return a value

I have a list of entries generated by PHP, each in their own div and each with a unique ID. I'm trying to develop an AJAX call that can remove each entry based on their ID, however whenever I run the script below, it always returns 0.  <div>     Some entry here     <button id="0" class="remove">Remove</button> </div> <div>     Another entry here     <button id="1" class="remove">Remove</button> </div> // ... and so on  <script>     $(".remove").click(function() {         var id = $(".remove").attr('id');         alert(id); // debug         // AJAX call here     }); </script>   Previously I tried the same thing except the other way around - the id returned by PHP was in the class attribute and the id attribute had the value 'remove' and this only returned 0 for the first button. The second button didn't invoke the jQuery script at all.  How can I pass a unique ID to the same jQuery call?


What is the most efficient desktop to install with mini.iso?

I have a friends previously xp machine, that is about 10 years old. It only boots through CD but I've made two different CD-R's with Lubuntu and it won't take. I do get mini-iso to load, and have installed Lubuntu, but is there a more efficient desktop than Lubuntu-desktop?   The computer has 256mb RAM, and when I had Lubuntu-Desktop installed half of it was used up by the desktop. The machine loads Chrome well enough and plays youtube videos barely, but getting movies to play through xbmc/vlc is almost impossible (even logging out and logging in directly to xbmc).   So is there any other desktop I can install other than sudo apt-get install lubuntu-desktop that would allow the computer to browse/watch movies.


I am writing a VB.net console application that calls ArcGIS Desktop 10.1 ArcToolbox geoprocessing tools from my code. Some of these tools use Python syntax and  that I suspect is caused by conflicting architectures. Is there a way to control which version of Python that ArcGIS uses?    System: 64 bit Windows 8.1 ArcGIS: 32 bit ArcGIS 10.1 Service Pack 1 Python: Both 32 and 64 bit versions installed (latter from ESRI's background processing download) My App: 32 bit VB.net (not Any CPU) console application.


$0 \times a \cong 0$ without exponentiation

I know how to prove $0 \times a \cong 0$ in categories admitting exponentiation (and initial objects, of course). But does this hold for categories that don't have exponentiation?  I don't have enough examples in my mental categories library to give a counter-example, nor have I managed to prove that $0 \times a \cong 0$ based on just the notion of products.


Epsilon Delta Proof: How do I use the definitions to prove

Prove the following using epsilon-delta definition:  Let $a \in \mathbb{R}$ and $f,g$ be defined on $\mathbb{R}$.  If  $$\lim_{x\to a} f(x) = 647 \tag 1$$  and $$\lim_{x\to a} g(x) = \infty \tag 2$$ then   $$\lim_{x\to a} f(x) + g(x) = \infty.$$  $$(1) \implies\forall \epsilon > 0, \exists \delta > 0, s.t. |x-a|<\delta \implies |f(x)-647| < \epsilon$$  $$(2) \implies \forall M > 0, \exists \delta_2 > 0, s.t. |x-a|<\delta_2 \implies |g(x)| > M$$  Not sure about this... I've set up the definitions. I believe we will have to take a minimum between the deltas for first two limits then use it in the third.  Anyone have any clues?


Is it possible to view Google Chrome bookmarks and history from the terminal

Is it possible to view Google Chrome bookmarks and history by using command line?


How are downvotes without sufficient reputation recorded?

The popup above is a result of trying to downvote as a user with less than 125 reputation. The popup, in case you can't see it, states the following (emphasis mine):     Thanks for the feedback! Votes cast by those with less than 125 reputation are recorded, but do not change the publicly displayed post score.   How are these downvotes recorded, and what do they do? Or rather, do they do anything at all?  The popup included is from trying to downvote a post on the  site with only the Association Bonus.


How to control a motor with only relays and push button?

Hello I´ve been working in this project for some days, I need to make a circuit with only relays that can make a dc motor start, stop and a reverse. The thing is that when you push the start or the reverse button the motor need to keep running, I can´t keep it pushed.  This is as far as I can get. SW1 turns the engine on, SW5 turns it off and SW7 reverse the motor but only if it is already running. What i need is that the reverse button also turns the engine on. Please help.  notes: -i can only use three push buttons and as many relays as needed. Yes is a school assignment.  THANKS!


To each vertex of a pentagon, we assign an integer $x_i$ with sum $$s=\sum x_i>0$$ If $x$, $y$, $z$ are the numbers assigned to three successive vertices and if $y<0$ , then we replace $(x, y, z)$    by $(x+y, -y, z+y)$. This step is repeated as long as there is a $y<0$. Decide if the algorithm always stop .  I know this question is already asked, but my question is, how much steps are needed until stop??


pgfplot connects first and last point of line in the surf plot

I'm plotting a surface from data file arranged in columns x,y and value. The result looks like this:     As you can see, first and last point of every line is connected. Relevant code:  \begin{tikzpicture} \begin{axis}[% ]% \addplot3[% surf] table[x index= 0,y index = 1,z index = 2, col sep=tab] {data.txt}; \end{axis} \end{tikzpicture}   Is there any way to fix this?


How to change title via button or anchor

I have a one page site with buttons on the top that direct you to different anchors, is there any way I can get the title to change every time I click the the button?


What is the difference between dragonborns and half-dragons?

Accordingly to the player handbook dragonborns are an own race originated by dragons. But I'm uncertain about half-dragons. Are they dragonborns themselves or are they a mix between dragons and other humanoids?  If they are not the same:   Do they differ in appearance (e.g. can half-dragons have tails or wings?)? Could an adventurer (or townsfolk) differ them?   Background: I stumbled upon half-dragons in Hoard Of The Dragon Queen and one of the PCs is a dragonborn, so I'm wondering if it is the same or rather what are the differences.


Intuitions behind Singular Value Decomposing generalizing eigen decomposition

Let M be mxn matrix then SVD of M will be UXW^* (sorry for X, assume summation). Then how does it generalizes eigen decomposition ? Since eigen decomposition is possible for nxn matrix and that are non-symmetric.


The countable union of countable ordinals is countable, using ZF

My understanding is that the more general case of this (the countable union of countable sets) requires choice to prove. However in the case of ordinals, it should be provable without choice since there is an explicit well ordering on ordinals. Based on this, how does one go about constructing the explicit surjection needed to prove this?


Plane Boolean modifier doesn't see a text object

I am trying to do a title and credits in a way of a simple motion graphic text reveal but when I add a modifier to a plane it doesn't see any text object to apply a difference operation to.


I want to store data in encrypted form in a sendable Data Extension and decrypt it while using. So basically, my DE will contain SubscriberKeys and EmailAddress. Email Address should be encrypted. But while sending email, I should be able to decrypt it.  Also, after email send, when this information goes to All Subscribers, it should still be in encrypted format.  How can I accomplish this?


For a given string(2 or 3 word) in a .txt file and print the whole line.

My .txt file contains these kind of content :  The Law and Lawyers of Pickwick, by Frank Lockwood                 21214 Frankenstein, by Mary Wollstonecraft                               20   The first string is book name,second is author and the last one is book number. I want to print the whole line when someone search with the author name.I tried using grep.  #!/bin/bash BOOKFILE="/home/sk/GUTINDEX.ALL" author=$1 if [[ -z "$author" ]]; then  echo -n "Author name : " read author fi grep $author $BOOKFILE   If I run this and search for Frank Lockwood it prints both the lines.But I want to print the line when the entire input string match(both the first name and last name)


Recently I received the "Tenacious" badge and noticed lots of answers I have posted had received 0 votes. So I started from the oldest ones and worked my way to the recent ones, deleting the bad and/or somewhat worthless posts on my mobile.  Every time I clicked the "Delete" link, I had to confirm twice. Bug or feature?  (Samsung Galaxy S III on Android 4.1.2)


How do I count words in a PDF file on OS X?

I'd like to count words on a PDF file on OS X. The inspector doesn't contain the word count.


Windows 7 Pro x64 hangs on boot when loading classpnp.sys

Don't know what happened but this happens almost every time I boot. Never happened before a couple days ago and I haven't even done anything.  Computer powers up, GRUB (From fresh Ubuntu 11.04 install) loads, Windows 7 starts booting.  I configured msconfig to show the file it's currently loading when booting (The similar list you see when you boot into Safe Mode) and when it gets to C:\Windows\System32\DRIVERS\CLASSPNP.SYS, it takes a couple more seconds to load than other files if it doesn't hang.  Before the hang, my wireless LAN card is detected and then sound is activated (I can tell 'cause these lights on my laptop change to red when it's mute/disabled and blue when it's not). The hard drive makes the sound it makes when it's loading except the sound's constant (The HDD light's on. Not flashing like it usually does) meani. I can disable the touchpad but the keyboard doesn't work because the numlock light doesn't come on when I press numlock.  OS:     Windows 7 Professional x64 SP1 Laptop: HDX16-1155CA CPU:    Core 2 Duo P7450 2.13 GHz RAM:    4 GB DDR2 HDD:    320 GB Fujitsu something   Also, I've tried sfc /SCANNOW and it said that my system is fine  Never happened before, all I have is the mouse installed  Update: Now it restarts sometimes while loading CLASSPNP.SYS


How to tell googlebot crawl more page from my site?

I have a small local news site, every one increase hundreds of articles. I have set a crontab, list new articles' url into a sitemap by hour.  for example, I have 24 sitemaps which is generated by hour.  sitemap01.xml which has included articles from 0:00 - 1:00   sitemap02.xml which has included articles from 1:00 - 2:00  <url>      <loc><![CDATA[http://www.example.com/article/'.$row['id'].']]></loc>   <lastmod>'.date("c",strtotime('now')).'</lastmod> </url>   I have checked sitemap-list in google webmasters, I find google don't crawl my sitemap everyday, some sitemap's last crawl date is 10 days before. So now it only increase 8-40 articles into google index everyday.  but when i use  cat /var/log/httpd/access_log |awk '{print $1}' |sort |uniq -c |sort -n |tail   I could see 7 googlebot ip address in my access_log, total access in my site 5000+ per day. What are they doing?   And If I use https://encrypted.google.com/webhp?hl=en#q=site:example.com&hl=en&tbs=qdr:h&start=0  some page would display in search resualt every hour, but they are only news article. when I released, it like a static page, only vititor's comments would be increased in it.  So how to let google crwal more of my page? make the crawl more effective? access all my new page and ignore the older page which it has been crawled?  Thanks.


Create quaternion based on where a unit is hit (shield effect as in Starcraft 2)

I'd like to implement a shield effect like that done for Protoss units in Starcraft 2. I'm guessing that the technique involved uses a partial sphere that is rotated to reflect where a unit is hit.  Assuming this is the idea, how can I create a quaternion to rotate this model to achieve the desired effect? My collision detection system conveniently relies on sphere-sphere intersection.  Edit: this is pretty much a dupe of , which has a pretty thorough answer.


not implies, not Leftarrow, description in the middle of an arrow in TikZ-cd

Is there a way to put $\nLeftarrow$ instead of some arrows in TikZ? Specifically, how do I change it to "B does not imply A" in the following code.  \documentclass{article} \usepackage{tikz-cd} \begin{document} \begin{tikzcd}[arrows=Rightarrow]    A \arrow[out=30,in=150]{r}{}\arrow{d} & B \arrow[out=210,in=330]{l}{}\arrow{d}  \\    E  \arrow{r}{} & F \end{tikzcd} \end{document}   One very primite way is to do something similar to the following, where at the description part in the middle of the arrow, use \Big\backslash.  \documentclass{article} \usepackage{tikz-cd} \begin{document} \begin{tikzpicture} \matrix (m) [matrix of math nodes, row sep=3em, column sep=3em]              { A & B \\           & C \\ }; \path[->,font=\scriptsize] (m-1-1) edge node    {$\Big\backslash$} (m-1-2) edge node {$\Big\backslash$} (m-2-2);     \end{tikzpicture}  \end{document}   But then, how do I put a description in the middle of an arrow in the first code?


Can I read a bool variable in a thread without mutex?

Is there anything wrong in following source code if I don't use mutex?  bool bStop = false;  void thread1_fun() {     while (!bStop)     {         doSomething();     } }  void thread2_fun() {     bStop = true; }


how to prove that $\lim\limits_{n\to\infty} \left( 1-\frac{1}{n} \right)^n = \frac{1}{e}$

I need to prove  $$\lim\limits_{n\to\infty} \left( 1-\frac{1}{n} \right)^n = \frac{1}{e}$$ For now, I only know the e definition: $\lim\limits_{n\to\infty} \left ( 1+\frac{1}{n} \right)^n = e $, and I need to proof all the partial results in between to reach the wanted result.


Distribution of the difference of two normal random variables.

If $U$ and $V$ are independent identically distributed standard normal, what is the distribution of their difference?  I will present my answer here.  I am hoping to know if I am right or wrong.  Using the method of moment generating functions, we have  \begin{align*} M_{U-V}(t)&=E\left[e^{t(U-V)}\right]\\ &=E\left[e^{tU}\right]E\left[e^{tV}\right]\\ &=M_U(t)M_V(t)\\ &=\left(M_U(t)\right)^2\\ &=\left(e^{\mu t+\frac{1}{2}t^2\sigma ^2}\right)^2\\ &=e^{2\mu t+t^2\sigma ^2}\\ \end{align*} The last expression is the moment generating function for a random variable distributed normal with mean $2\mu$ and variance $2\sigma ^2$.  Thus $U-V\sim N(2\mu,2\sigma ^2)$.  For the third line from the bottom, it follows from the fact that the moment generating functions are identical for $U$ and $V$.  Thanks for your input.  EDIT: OH I already see that I made a mistake, since the random variables are distributed STANDARD normal.  I will change my answer to say $U-V\sim N(0,2)$.


I might be ignorant if there exists such functionality. Can I search for a friend on Stack Exchange with their email address?.


What is the difference between model hyperparameters and model parameters?

I have noticed that such terms as model hyperparameter and model parameter have been used interchangeably on the web without prior clarification. I think this is incorrect and needs explanation. Consider a machine learning model, an SVM/NN/NB based classificator or image recognizer, just anything that first springs to mind.   What are the hyperparameters and parameters of the model? Give your examples please.


Strange coloured border appearing around windows

Recently, I have noticed that on most applications I have on Ubuntu 16.04, when I load the application, the window is displayed with a strange multi-coloured border (see the images below). If I maximise the window though, the border disappears and the window is displayed as expected.  This started happening for no apparent reason. If I reboot my machine, things return to normal at first, but after a while the problem comes back.  The issue occurs on most applications, including Nautilus, Software Centre, Terminal, System Settings, etc... I also get the same border appearing when I right click on the desktop, with the border surrounding the pop-up menu.  However, I have noticed that it does not happen on Chrome, but it does happen on other applications which did not come with Ubuntu by default.  Any ideas on what is causing the problem? Thanks!


How to refer to a cell's content from a query in Google Spreadsheets?

=QUERY('F/O OFF'!1:1000, "select H, J where B='CIN'label H'', J''")   Right now this formula works fine,  but i have to change the "where B=" for each row in the sheet.   I want to get it so where B= (The value in colA of the row the query is being inputted in)


How to prevent Google (and others) from indexing the site under construction?

Recently I faced with the situation that the wrong site pages (with wrong URLs, wrong content) was indexed by Google during the site developing. Should I place robots.txt with  User-agent: * Disallow: /   And delete it after the site developing was finished? Or I shouldn't bother with it at all?


In anime, why high school students are not allowed to work?

I was confused about why in anime, high school students were not allowed to work. I understand in real life that they have to have permission from the school. Maybe I'm just reading into it too much as a Westerner.


So I have never actually even tried to go into Hardmode yet, for the simple reason that I've never truly felt fully prepared for the challenges that await me once I enter the Hardmode World...coupled with nostalgia for my old world, but setting that aside...  What should a player have before they enter Hardmode?  How much of the map should be explored before they enact this permanent map change?  What essential resources should the player concern themselves with preserving before the transformation?    In short, how should I prepare for Hardmore?   Important Note - I do not need help preparing for the Wall of Flesh.  I already know that I need a battle platform stretching the length of Hell and I have the gear to fight it, I am more worried about preparing the entire rest of my world.


A normal subgroup that is not a characteristic

In the book I'm study is written:     A normal subgroup of a group need not be characteristic.   And as an exercise I'm supposed to find an example, it also said that is pretty hard to find one. After trying for two days I wasn't able to find one example.   So, I'm asking for an example of a group $G$ with a normal subgroup $H$ that is not a characteristic of $G$.  I will add some context because maybe it will clarify why the book said it is difficult to find an example: the main problem with the exercise is that until it the book had only covered Group Definition, Subgroups, Lagrange's Theorem and Homomorphisms. So I'm supposed to find a example with such lack of advanced tools.


How to centralise images with an absolute position?

I have three images in a
. I want the images to overlay each other (for a slideshow using opacity) and remain central on my website.   To make the images overlay I set their position to absolute (position: absolute;). However, this conflicts with my method of centralising my images. To make my images central, I give images the following properties: margin: 0 auto; display: block; This doesn't work when the images' positions are set to absolute. What other methods can I use to make my images overlay and/or centralise images.

   img { position: absolute;    margin: 0 auto;     display: block; }


Let $(c_n)^∞_{n=m}$ be a sequence of positive numbers. Then   we have   $\lim \inf_{n \to \infty} \frac{c_{n+1}}{c_{n}} \le \lim \inf c_{n}^{1/n}$   Let $L = \lim \inf_{n \to \infty} \frac{c_{n+1}}{c_{n}}$. If $L = -\infty$ then by definition $L \le \lim \inf c_{n}^{1/n}$. Assume $L$ is a non-extended real number. Then for there exists an $N \ge m$ such that $\frac{c_{n+1}}{c_{n}} \ge L-\epsilon$ for all $n \ge N$. Thus $c_{n+1} \ge c_{n}(L-\epsilon)$, $c_{n} \ge c_{N}(L-\epsilon)^{n-N}$ then denote $A = c_N(L-\epsilon)^{-N}, c_n =A(L-\epsilon)^n, c_n^{1/n} \ge A^{1/n}(L-\epsilon)$, $\lim_{n \to \infty} A^{1/n}(L-\epsilon) = L - \epsilon$. That is $\lim \inf_{n\to \infty}c_n^{1/n} \ge L - \epsilon$, since this is true for all $\epsilon$ than $\lim \inf_{n\to \infty}c_n^{1/n} \ge L$  Is this proof correct?


Does a set of $n$ independent vectors in $R^{n}$ always span  $R^{n}$?  If so, what's the reasoning behind this?


Given the characteristic polynomial $\chi_A$ of an invertible matrix $A$, I'm to find $\chi_{A^{-1}}$.  I can see that this is theoretically possible. $\chi_A$ uniquely determines the similarity class of $A$, which uniquely determines the similarity class of $A^{-1}$, which uniquely determines $\chi_{A^{-1}}$.  Calculating the coefficients of $\chi_{A^{-1}}$ explicitly and then relating them to the coefficients of $\chi_A$ seems unfeasible. I thought about calculating the factors instead, which could be easier since I at least have some idea what the linear factors $\chi_{A^{-1}}$ are (since I can see how to get the eigenvalues of $A^{-1}$ from those of $A$), but that doesn't help me with potential higher-degree irreducibles or repeated linear factors. Also, we're not supposed to know the eigenvalues of $A^{-1}$, at least I don't think so, since calculating them is the next question.  Any hints?


Getting polygons of all countries and ISO-3166-2 subdivisons

In order to do reverse geocoding lookups to find a country (as ISO-3166-1) and the subdivision (as ISO-3166-2) for given coordinates I am looking for a way to get all polygons of all countries and their subdivisions.  Reverse geocoding lookups with Google Maps or other services either do not always return the country and subdivision (Google Maps), or sometimes they are incorrect (geonames.org). As I understand it all countries and subdivisons are available in the openstreetmap data, but I do not know how to only retrieve the polygons - no map data, no points of interest or cities are necessary, only the outlines of all subdivisions with the given country and subdivision codes. Then I can check myself if a given point is within any given polygon, or near it.  Does anyone know how to retrieve this data from the openstreetmap data, or is there any other source for this data?


What are the limits of Wolverine's immortality?

We all recognize the regenerative capacities of the countless characters from Marvel and DC, and Wolverine is one the first that comes in my mind when speaking of immortality (or "unkillability"?), after Deadpool and many others.  There is already a , and although it is also included in X-Men universe, the logic clearly is not the same for both characters. Furthermore, after the events in many X-Men movies - particularly in X-Men Origins or , which in my country is titled "Wolverine: The Immortal" -, we also perceive much more the immortality or semi-immortality after him being shoot in the head or losing part of his members.  I'm a layman when speaking of Marvel comics, but I'm always very curious when it comes to be a subject matter of immortality. For example, what would happen if Wolverine was vertically cut in half? Two wolverine are generated? At least two brains, in ideal conservation ambient, could develop by themselves?  In the real world something similar can happen with non-differentiated stem cells, but I don't know what logic is used when concerning adamantium and tissue regeneration in Marvel universe. I wonder if there are any references that put this topic in evidence in the comics.


How to turn off Sticky Edges in Ubuntu Gnome

When I used Unity, I remember seeing the setting for the Sticky Edges in Settings -> Displays, but I can't find that option in Gnome. Where can I turn on/off Sticky Edges in Gnome?


Resolving T to int, float, decimal or double to compare calculation performance

Hi is it possible that the following method somehow recognizes that it can be only int, double, decimal or float and add them with the + operator. If I use dynamic then it is a problem because I wish to compare the time for addition for the different types and if they are cast to dynamic I do not know what will be the effect. Thanks.      public static void Addition<T>(T number) where T:int, double, decimal, float                 {     //calculate elapsed time for operation      var x=  number + number;// cannot add T + T     }


I updated from OpenJDK 7 to 8. I uninstalled 7, which uninstalled the IcedTea plugin as well. I tried to reinstall IcedTea with      sudo apt-get install icedtea-7-plugin   But it doesn't work. When I try to launch topcoder jnlp file, it fails. Also, it doesn't load any java plugin in Google Chrome. It was fine with OpenJDK 7. Is there a newer version of IcedTea for OpenJDK 8?


How to go beyond the impossibility to create a command whose name starts with "\end"

The following simple file gets an error during compilation:  \documentclass{article} \newcommand{\enda}{E} \begin{document} dddd \end{document}   The error message is:  ! LaTeX Error: Command \enda already defined.            Or name \end... illegal, see p.192 of the manual.  See the LaTeX manual or LaTeX Companion for explanation. Type  H <return>  for immediate help. ...                                                l.2 \newcommand{\enda}{E}  Your command was ignored. Type  I <command> <return>  to replace it with another command, or  <return>  to continue without it.   It seems that what ever I put after \end (say \endb, \endklghfsgfljs or whatever valid command name) Latex will produce the same error. When the d of end is changed into another letter (say, s) this seems to go fine.  How do I define a command with the name I want?  Note: my question is not whether this is a reserved word but how to bypass the obstruction. A slightly different question is . I couldn't find this question with my intentions in mind. I expect that somebody stumbling upon the same problem as me would find this question more easily than the one in the link.


calculus on manifolds (spivak) problem 2-41 (c)

2-41. let $f:\Bbb{R} \times \Bbb{R} \rightarrow \Bbb{R}$ be differentiable. for each $x \in \Bbb{R}$ define $g_x: \Bbb{R} \rightarrow \Bbb{R}$ by $g_x(y)=f(x,y)$. suppose that for each $x$ there is a unique $y$ with $g'_x(y)=0$; let $c(x)$ be this $y$. (a) If $D_{2,2}f(x,y) \neq 0$ for all $(x,y)$, show that $c$ is differentiable and $c'(x)=-\frac{D_{2,1}f(x,c(x))}{D_{2,2}f(x,c(x))}$. Hint: $g'_x(y)=0$ can be written $D_2f(x,y)=0$. (b) show that if $c'(x)=0$, then for some $y$ we have $D_{2,1}f(x,y)=0$ $D_2f(x,y)=0$ (c) let $f(x,y)=x(y \,log \,y \,- \,y)- y \,log\, x$. find $\underset{\frac{1}{2}\leq x \leq 2}{max}(\underset {\frac{1}{2}\leq y \leq 1}{min}f(x,y))$.  for the given $f(x,y)$, $c(x)=e^{log\,x/x}. \, c'(x)=0 \implies x=1$ and since $c(1)=1,$ according to part (b), $D_{2,2}f(1,1)=0$ and $D_2f(1,1)=0$ But how do I know $\underset{\frac{1}{2}\leq x \leq 2}{max}(\underset {\frac{1}{2}\leq y \leq 1}{min}f(x,y))$ occurrs at $(1,1)$? What other critical points do I have to look at? please give a hint.please do not provide solution.


Putting unlabelled balls into labeled boxes

How many ways are there to put $50$ unlabeled balls into $100$ labeled boxes? If empty boxes are allowed and you're also allowed to put as many balls as you want into a single box, would the answer be $\displaystyle\binom{149}{50}$?


Should limits be placed on new users who create paths of destruction?

Specifically this user:   His questions are coming quickly and have problems:   They require significant editing (which the SO community is stepping up, but it might just be a waste of time). Over half get closed or close votes. (Which is a sign that SO is self-cleansing) Some are duplicates of other questions (even his own). A large majority start with the same title: Require a code So far none of his questions have accepted answers.   For the most part SO is down-voting, editing, and closing the poor questions.  This is good, but if it keeps going is just a waste of time.  What can be done to help new poor users to learn to get better at asking questions?    Should they be limited to one question every 12 hours if previous questions are poor? (Poor could be determined by negative score)  Is there anything else that can be done to help them to learn to be better or at least stop the user from creating more editing work?


What are the "modified" and "standby" RAM regions in Resource Monitor?

The "Resource Monitor" tool of Windows 7 shows me a typical memory map like in the screen shot above. What are the orange colored modifed and blue colored standby regions in this graphic? What exactly are their functions?


Is there any method to edit a text file without opening it?

I have a text file which has about 70000000 lines in Linux system.  How to delete the lines from 40000000 to 50000000 without opening the file?  Thanks.


If I cancel my apple music membership will I lose all my music that i downloaded from the app? Is there any way I could keep the music ? I only need to switch my App Store country since I am moving to Boston from Indonesia..


LibreOfficeCalc window is shrunk to a line and is unclickable

I moved the LibreOfficeCalc window from full width to my other screen and suddenly it became just a line:   Now I cant find it on my desktop anymore:  The problem is, even if I close the LibreOfficeCalc from the navbar and reopen it again, its still not visible. Probably because it saved the "line" width as default. I can't find anything to click and expand on my desktop. What can I do so I can use it again? I already tried to remove and reinstall it, but the issue remains. Every file that I open is now a line.


"Proofreader" Badge awarded to approved or rejected 100 suggested edits but if you see my suggestions count it is . So my question is why I am not getting badge of "proofreader" or there is something else required for that?


What is BVH and why is it slowing down my render so much?

I'm attempting to render a long character animation in cycles, and before each frame is starting to render, bvh is coming up and making everything super slow.


How do I use SessionID for subsequent requests after successfully logging in

One of our provider has a salesforce system in place and they have send us the URL. I added the reference as a Web Reference since adding it as a Service Reference had some issues.  Now, I am able to successfully login to the service and get the session ID. Now question is that how can I use the session ID in my subsequent Upsert request?   DoI have to add it to the SOAP header? If so, how?


Physical meaning of same pressure on the same plan (hydrostatic paradox) with different weight above them

In this picture the points on red have the same pressure because the weight of the fluid is the same above them. But according to pascal law the point on black must have the same pressure(both 3 points are on the same plan),but the weight of the fluid above the point on black isnt the same. So how do we explain this?


Get parent directory of shell script's directory

I have a shell script here:  /node_modules/.bin/exec.sh   in the exec.sh script, I want to obtain the path of the directory's parent directory that the script is contained in (not pwd/cwd!). I can obtain the containing directory like so:  `dirname $0`   which will yield:  /node_modules/.bin   but I am looking to get at one directory higher, I just want to get  /node_modules   I am having trouble searching for the answer, my guess is:  `dirname $1`   but just a guess, not sure if that's right at all. Can anyone give an explanation of how to do this and how it works?


"All Sites" has wrong information for the Japanese SO

Currently, on the Stack Exchange , the row for スタック・オーバーフロー (Stack Overflow in Japanese) has two obviously-wrong values:  visits/day: 0  site age: 2013y11m   If the latter is used somehow as the denominator in calculating the former, that would explain how these are caused by a single bug.


A term to describe a phrase that can be changed without having to know the origin

I'm sure I read about this on this website, but I am clueless as to what it was.  An example may be adding 'gate' to the end of scandal titles.  People understand it enough to use it to describe other scandals with out knowing where it started.  I have a vague recollection of the name of this having something to do with snow??? but please don't quote me on that


How to compare my slope to 1 rather than 0 using regression analysis and t distribution?

I would like to know if i can reject, using a linear regression and a t-distribution, the following Null hypothesis:  b=1  where b is the slope of my linear regression. My hypothesis is that b>1.  I am using R, and i know how to test whether my slope is significantly different than 0 but not if it is significantly different than 1!  Thank you for your time.


Terminology for a certain mesh phenomenon

What is the terminology for this abomination, where the face folds in on itself and requires triangulation to function? I'm assuming it has to do with something relating to normals, but I'm not sure specifically. Additionally, what is the terminology for its inverse, where a face has a level of flatness to it?


Commutative Diagram not working for slides

I asked this  some times ago and the given solution perfectly worked for me. Now I am trying to draw the same thing in a slide and it's not working.   Here's the code I used:  \begin{frame}  \frametitle{Almost Complex Structure on a Riemann Surface}  \begin{itemize}  \item   <1-> So, we get a diagram: \\  \begin{center}  \begin{tikzcd}[row sep = huge, column sep = huge] T_p M \arrow[r, "J"] \arrow[d, "d\varphi_p", swap] \arrow[dd, bend right = 100, "d\psi_p", swap] & T_p M \arrow[d, "d\varphi_p"] \arrow[dd, bend left = 100, "d\psi_p"] \\  \mathbb{C} \arrow[r, "M_i"] \arrow[d, "d(\psi\circ\varphi^{-1})_0", swap]                             & \mathbb{C} \arrow[d, "d(\psi\circ\varphi^{-1})_0"]                       \\  \mathbb{C} \arrow[r, "M_i", swap]                  & \mathbb{C}                                \end{tikzcd}\\  \end{center}  \end{itemize}  \end{frame}


Trying to create a game for final project, character does not move with arrow keys

So im a newbie and im trying to get my game to get input from keyboard to move a fixed distance (lets say 50) so if you press up on arrow key you go up by 50 and etc. When i run the game i cant use the arrow keys to move the hexagon..      import java.awt.*;     import javax.swing.*;     import java.awt.image.*;     import javax.imageio.*;     import java.io.*;     public class SuperHexagon extends JFrame {   public static final int WIDTH = 1440, HEIGHT = WIDTH / 16 * 9;     public SuperHexagon() {     setPreferredSize (new Dimension(WIDTH, HEIGHT));     setMaximumSize (new Dimension(WIDTH, HEIGHT));     setMinimumSize (new Dimension(WIDTH, HEIGHT));      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     setResizable(false);     setLocationRelativeTo(null);      setVisible(true);   }     public static void main (String[] args) throws IOException {     JFrame frame = new SuperHexagon();     int hexX = (WIDTH / 2) - 23, hexY = (HEIGHT / 2) - 23;       Graphics g = frame.getGraphics();     BufferedImage bgImage = ImageIO.read(new File("Images/gameBG.png"));     BufferedImage hexImage = ImageIO.read(new File("Images/hexagon.png"));     frame.addKeyListener(new KeyInput());      g.drawImage(bgImage, 0, 0, null);     g.drawImage(hexImage, hexX, hexY, null);     g.dispose();      } }   The key inputs:  import java.awt.event.KeyEvent; import java.awt.event.KeyAdapter;   public class KeyInput extends KeyAdapter {    /* Coordinates that player can move (3x3 grid)    * (645,330)(720,330)(795,330)    * (645,405)(720,405)(795,405)    * (645,480)(720,480)(795,480)    */    public void keyPressed(KeyEvent e, int hexX, int hexY) {     int key = e.getKeyCode();      if (key == KeyEvent.VK_UP) {       hexY -= 75;      }     if (key == KeyEvent.VK_DOWN) {       hexY += 75;     }     if (key == KeyEvent.VK_RIGHT) {        hexX += 75;     }     if (key == KeyEvent.VK_LEFT) {       hexX -= 75;     }   }  }


How to install a Broadcom BCM4306 Wireless on MacBook Air

I installed Ubuntu 19.10 on my MacBook Air and I am not able to connect to the wifi.   I executed the to following command:   jb@jb-MacBookAir:~$ nmcli dev DEVICE  TYPE      STATE      CONNECTION lo      loopback  unmanaged  --          jb@jb-MacBookAir:~$ sudo lshw -C network   *-network                         description: Network controller        product: BCM4360 802.11ac Wireless Network Adapter        vendor: Broadcom Inc. and subsidiaries        physical id: 0        bus info: pci@0000:03:00.0        version: 03        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: driver=bcma-pci-bridge latency=0        resources: irq:18 memory:b0600000-b0607fff memory:b0400000-b05fffff   jb@jb-MacBookAir:~$   So as explained in "" I installed "b43-fwcutter" and "firmware-b43-installer" by following the following procedure:   "Téléchargez le pilote ici et sauvegardez-le sur un support externe, Copiez l'archive dans votre dossier personnel, Puis dans le dossier /lib/firmware/ avec la commande suivante que vous entrez dans un terminal: sudo cp broadcom-wl-5.100.138.tar.bz2 /lib/firmware/ Déplacez-vous dans le dossier /lib/firmware/ : cd /lib/firmware Décompressez-y votre archive avec les droits d'administration: sudo tar xfvj broadcom-wl-5.100.138.tar.bz2 Nettoyer votre dossier: sudo rm *.bz2 Redémarrez votre ordinateur."  Unfortunatly it didn't work. It is still saying 'No Wi-Fi Adapter Found".   Do you have any idea how to solve this problem ?   Thank you so much!   Jeremy


Is it okay to SELECT * if desired behavior is for the query to automatically add new columns?

I use a view to surface every column in a wide, denormalized table for reporting users.  The reason I use a view instead of the table directly is that the view has logic to control access by user.  Every time I add a column to the wide, denormalized table I want it to automatically show up in the view.  Many here on Stack Overflow say SELECT * is never okay.  In this case is it okay or should I just take the hit of updating the view every time I add a column to the table?


When I use sudo apt-add-repository https://dl.winehq.org/wine-builds/ubuntu/ to add winehq this shows up  E: The repository 'http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/wine/wine-builds/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.


How would you categorize an action that is characteristic of a brown-noser (somebody who tries too hard to impress)?


Convergence implied by partial sequences.

I am not sure how to deal with this Question:  Show, that the sequence $(a_{n})_{n \in \mathbb{N}}$ converges towards the limit $a \in \mathbb{R}$, exactly when every subsequence $(a_{n_{k}})_{k \in \mathbb{N}}$ of $(a_{n})_{n \in \mathbb{N}}$ owns itself a converging subsequence $(a_{n_{k_{j}}})_{j \in \mathbb{N}}$ towards $a$.  To show:   $PS(a_{n}):=$ the set of all subsequences of a given sequence.  $$a_{n}\rightarrow a \Leftrightarrow \forall a_{n_{k}} \in PS(a_{n})\; \exists \; a_{n_{k_{j}}} \in PS(a_{n_{k}}): a_{n_{k_{j}}}\rightarrow a$$  It is easy to show the "$\Rightarrow$" direction, as every subsequence of a given converging sequence, converges towards the same limit.  But what about "$\Leftarrow$"?


Java int[][] array - iterating and finding value

I have an array in the form of 'int[][]' that represents the co-ordinates of a small grid. Each co-ordinate has been assigned its own value. eg array[0][4] = 28......  I have two questions. Firstly, how do I iterate through all the stored values. Secondly, I want to be able to input a value and have its specific co-ordinates in the grid returned. What would be the best way to approach this?  Thank you for any help!


Administering a potion to a conscious enemy

Potions (DMG, page 139): Drinking a potion or administering a potion to another character requires an action.   Here it says "to another character", not "to an ally". Does this mean that by RAW you could force feed a Potion of Poison to an enemy without any roll?  I don't think that would make sense. But a scenario like this came up in one of my games and I wasn't sure how to handle that. I told the player that he would have to grapple the enemy first, then succeed on another grapple check with disadvantage, in order to force the enemy to drink the potion.  Are there any rules concerning such a maneuver? How could I have decided better?


What does the phrase “I’m down with” mean?

I was wondering about the meaning of:      I am down with something.   Also, I was wondering whether people say:     I am up with something.   If so, what does it mean?


Seem to have lost 4 Silver badges and 10 Bronze badges

I updated my email on SO, and for some reason now, I've lost 4 silver badges and 10 bronze badges. Not sure what is going on here, does anyone have an idea?


Merge two vectors without sorting them in C++

I have two vectors that I want to merge without sorting the elements:  A = [a d f h] B = [b c e g] C = [a d f h b c e g]  // I want this   std::merge and std::inplace_merge end up sorting the vectors. Is there any way of doing this other than manually reading the two vectors in succession and pushing the values into a new vector?


Png Textures Showing Black Mask when overlapping with other png textures

recently i've been wanting to sculpt a bird, so my first move was testing out feathers and noding them up. Everything was going great, the transparency was working the textures were working but when i started to use hair particle system, i saw that the png files masks where starting to show. After this i started to stack up 16 png textures and they even started to show the png mask. I dont know if there are anyways to fix this but if there is i would be thankful! Problematic Picture:  Node Setup for Texture:


This question came up recently:  John III, the third king of Johnland was very angry with John II, who killed the founder of Johnland, the beloved John I. By his new law the digit $2$ was forbidden to use. The numbers were listed as $1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, $$ 15, 16, 17, 18, 19, 30, 31, 33, \dots $ What was the $2021$st number in this new system?  I then came up with this: Sol.:  First, I studied how many numbers would be ‘skipped’ in the system within a power of 10; 100: 0 101: 1 102: 20 103: 300 104: 4000 105: 50000 The pattern is quite clear. Skipped numbers before 2021st number: 300 x 2 + 1 x 2 + 0 x 1 = 602. However, in 602 there are some skipped numbers: (300 x 2 + 1 x 2 + 0 x 1) + (20 x 6 + 0 x 2) = 602 + 120 Also in 120 there are some more: (300 x 2 + 1 x 2 + 0 x 1) + (20 x 6 + 0 x 2) + (20 x 1 + 1 x 2) = 602 + 120 + 22 And in 22: (300 x 2 + 1 x 2 + 0 x 1) + (20 x 6 + 0 x 2) + (20 x 1 + 1 x 2) + (1 x 2 + 0 x 2) = 602 + 120 + 22 + 2 There are none in two.  From there I didn't know what to do with myself and just got the answer in python, but that's cheating, so I would like to know how I can hope to solve this question with pure maths. Cheers!


In eight ball pool , what happens if the player clears all his balls and pockets the eight ball together with opponent's ball?

From what I read it's not defined as a loss in the list of losing shots, but I'm not sure.


What is a single word to describe a person who is quick to blame others or the system in almost any situation, regardless of whether that is legitimate or not?


Exploring ocean depths: is pressure an issue? Should it be?

An upcoming adventure will have the party exploring the depths of the ocean. Breathing underwater shouldn't be an issue for them, as there are both items and rituals to take care of that, however, I was wondering what to do about about pressure, since none of these options mention it. I'll have to split my question into two, since they are closely related.   Is pressure an issue in 4e adventures? Is it mentioned in any of the published material? Has it been ruled anywhere that options that enable water breathing also grant immunity to pressure? Should it be an issue? This is somewhat subjective, but I really am wondering what other people have done. Would it be unresonable to assume that these options grant immunity to pressure? Should the players work to find another solution?


If a tunnel is dug along a diameter of the Earth, and a ball is dropped in the tunnel from a certain height $h$ above the surface of Earth, what should the motion of the ball be as seen from the Earth?   The answer says it'll be along a straight line and periodic, but not simple harmonic. I understand the former. But why will it not be simple harmonic?  From what I could make out, the mean position would be the center of the Earth, with the force of gravity acting on the ball. Speed would be maximum at the mean point (center of the Earth), and minimum at the extreme positions (surface of the Earth).


Why visible light satisfies Maxwell equations?

As it is described in standard textbooks I looked at, the Maxwell equations were first established for electromagnetic fields created by electric currents. Then it is stated that it was discovered experimentally (by Kohlrausch and Weber) that the electric constant in these equations equals the speed of light. From that it is concluded that the visible light is a special case of electromagnetic field.  Thus it satisfies the Maxwell equations.  Unless I miss something, it seems to me that the last conclusion is a too strong conclusion of the fact of coincidence of the speeds of propagation of light and of EM wave. Is there a more direct verification that the visible light satisfies the Maxwell equations?


The age of terror is an age of shocks. What is a difference between "the+noun+of" and "a+noun+of"?

I thought when a noun followed by "of something" has to be addressed with "the" because it is subject to the following of... However, I found the sentence such as "The age of terror is an age of shocks." Should be it like "The age of terror is the age of shocks"? Please give me some advice.


How to read html element values from string which contains the html code

Following is sample html code, Similar code i have in String variable and i need to read each values of only "select" and add it to some collection. Thanks in advance.  `   <head>  <title> Sample HTML </title>  </head>  <body>  <form id="form1" runat="server">    <h3> Sample Example </h3>    <p>Select items from the list<p>     <select id="Select1" runat="server">      <option value="Text for Item 1" selected="selected"> Item 1 </option>      <option value="Text for Item 2">Item 2</option>      <option value="Text for Item 3">Item 3</option>      <option value="Text for Item 4">Item 4</option>      <option value="Text for Item 5">Item 5</option>      <option value="Text for Item 6">Item 6</option>   </select>     </form>  </body>  </html>`


I want to remove some photos from , because they are breaking my privacy (they contain my personal information). How can I do that or who should I ask to do that?


I have just acquired a new laptop, ASUS ROG Strix GL503VD and i have some problems and i hope you can help me.  So i have installed the latest version of windows 10 pro (1709) and i am having major spikes even when i'm not in games, just browsing around. I noticed that these spikes come from GPU usage which goes to 100% very briefly as you can see in the image.    Also at times i have black screen which looks like the driver is reloading, yet i am up to date with all the drivers (I'm using GTX 1050 4gb and installed the latest drivers with nVidia Xperience). I noticed that the process taking up 100% of GPU is System. Could this be a windows problem ? If so, would a downgrade help ?  My specs are : Video : NVIDIA Geforce GTX 1050 4GB, CPU : Intel Core I7-7700HQ, RAM : 8GB


Find all $|kh - ij|$ such that there are infinite integers $x$ such that $gcd(xh + i, xj + k) = 2019$ given that $(h, i, j, k)$ are all integers.   I tried using the Euclidian Algorithm, but I'm not that good with mods so I didn't get anywhere.


Prove a binomial identity $\sum^{n}_{k=0}\binom{n+k}{k}2^{-k} = 2^n$

I was asked to show that   $\sum^{n}_{k=0}\binom{n+k}{k}2^{-k} = 2^n$ using pascal identity. I don't know how to do it. Whenever I was trying to use $\binom{n+k+1}{k} = \binom{n+k}{k}+\binom{n+k}{k-1}$, my index is always off by 1.


Inherit Time Machine backup after changing source hard drives

I am using Time Machine to backup an external HDD (A) (2 TB) linked to my computer to an external 6 TB HDD drive.   I now had to shift the data from HDD (A) to a new 3 TB one (B). Is there a way to continue the backup of the data so that Time Machine doesn't think it has to start the backup of (B) from scratch? Does TM automatically detect that the data on the new hard drive (B) are the same as the ones previously backed up on the old hard drive (A)?   Given how flimsy HDD are, I thought this would be a common problem. But I didn't find anything in the questions.


How do I mark a question as a community wiki? I know how to mark a answer as a community wiki, but I couldn't figure out how to mark a question as one. I don't see the little check.


Special characters like â€˜ on view laravel

I am rendering articles from database. But it shows special characters on page.  ex. â€˜MINORITYâ€™ CAN SHOW THE â€˜MAJORITYâ€™ WHO IS IN CHARGE!   I am using laravel 5.2 and mysql. How can I avoid this ? I have used following in , But it doesn't resolved problem.  <meta charset="utf-8">  Also tried, echo $newtitle = html_entity_decode($string, ENT_QUOTES, "UTF-8");   Please help!


need to create a random number between 10 and 20

I am trying to generate a random number between 10 and 20 for my program but the numbers being generated are less than 1 and are to 2 decimal places e.g. 0.64, 0.34 etc..  Dim TrigB As Random     Dim numberb As Integer     TrigB = New Random     numberb = TrigB.Next(10, 20)     TrigRdmb.Text = numberb.ToString   what do i need to change so that it produces a number between 10 and 20  thanks


Shell:Why do I need spaces when using pipe symbol?

As stated in  (and especially in John1024's answer, |  is a metacharacter and hence, does not need spaces around it.   It makes me really confused because when I try to pipe a command I get an error "<cmd>: command not found". If I delete the space after the pipe symbol, the command runs perfectly. Even stranger: after successfully piping a command, I can run the same command with a space after the pipe symbol.   For instance :   man bash | grep foo will return -bash: grep: command not found man bash |grep foo will output 3 lines containing 'foo' man bash | grep foo will now run and output the 3 same lines   I'd be really grateful if anyone could explain this behavior


(Google) Title of page not updated, everything else did

My website changed significantly this month.  Amongst the changes was the website's title.  Two weeks ago, I finally used Webmaster Tools and submitted the page.  So far, Yahoo and Bing have updated the title in the search results, but not Google.  I've resubmitted via Webmaster Tools the website, and the bots have crawled the page, and have added "content keywords".  But the title still doesn't match.  The "content keywords" lists many of the words in the new title (but contains keywords of the existing title also).  Must say that 4 of the top 5 key words in the "significance" list are the new title's.  Still, no change.  Any remedies for this problem?  Is adding the "alt" tag for the logo significant enough to trigger the change?  There isn't an appropriate place to put the company name between  tags on the front page.  Any suggestions?  Thanks.


Note: This may not be correct mathematical term, so in case of confusion, I mean what division is to multiplication. If not, just poke me in the comments.  I was given this the other day:  $2^x=8$  Which I solved as follows:  $2^x=2^3 \implies x=3$  What did I actually do to solve the equation?  Does this apply for other numbers and is there a general rule? I.e. $n^x$


I'm unable to upload any image using the SE Android app.        Screenshot with error is uploaded via web form.   App Version: 1.0.95 Device Manufacturer: LGE Device Model: LM-G710 OS Version: 8.0.0 (190492326deb8.FGN)


Batch importing all vector types of hundreds of DXF files

When importing dxfs, you get a window asking you to select vector layers to add. With all the dxfs I've imported so far, that has had two layers called entities, one of which is points and one of which is linestrings. I select all, click OK, and then the file imports. This has to be done for each dxf. Today I had to import approximately 200 dxfs (which I eventually combined using the data management tools.) Having to click on select all and then on OK, to select the vector layers for each and every one of those dxfs was very tedious! Is it possible to set QGIS to select all automatically as it imports dxfs, without my having to sit there for half an hour repeating those clicks? The dxfs were created from NTF tiles, using the LL2DXF converter. Unfortunately, many of them will not open in Autocad due to an invalid block name so I can't combine them in CAD if there are lots. I do have a script that can strip out the blocks, but it is a little slow and has to be used one file at a time. That's OK for a small number, but today I had a very large area of map to convert and there are other towns to do over the coming weeks.


90s fantasy novel about a girl on quest with talking pig (I think)

I'm looking for a fantasy novel I read in the 90s. Heroine begins the story overweight and has to go on a long quest (don't remember why). Along the way she acquires a group of animal/spirit? sidekicks, including a smartass pig, I think. By the end of her quest she has lost weight - not the main point of the book of course, but it's a detail that sticks out.   I think she developed magical powers during her quest, which she may have been surprised to discover? That's about all I can come up with. Cover was a girl walking in typical fantasy/forest scene with the animals, as I recall.It was a humorous, lighter fantasy. Any ideas?


How can you insert more than one data tag on a /summon spider command?

So, I tried  /summon spider 100 20 100 {Health:16.0f}{CustomName:Webby} then evreything that I could put in the middle with commas and full stops but it won't work, it'll let me use only one data tag but I am making a map that requires several of them for each mob. Obviously I am using Command Blocks in 1.12.2.  Thank you.


Can I read the public SSH key of another user?

The public component of SSH keys theoretically don't need to be kept private. It was therefore to my surprise that I was unable to read the public key of another user on the system:  andreas:~$ cat /home/bob/.ssh/id_rsa.pub cat: /home/bob/.ssh/id_rsa.pub: Permission denied   The permissions of the key file allow me to read the id_rsa.pub file (644), the problem is the .ssh directory has the permission 700.  Is there any system in place for listing the public keys of other users on the system without having to be root or logging in as each user individually?


I wrote some text in Inkscape using a font called ITC Franklin, then exported to SVG to be able to import it into Blender.   However, it seems the SVG doesn't create instructions for drawing the curves of the font. It just includes a reference to the font used so that whatever application using it is supposed to use that font.   Not sure how it works, but when importing into Blender, it doesn't show anything.


Google Spreadsheets Messes Up Comments When Sorted

I added comments to a bunch of cells. When I then sorted the cells, the comments did not follow their original cell and now was connected to the new cell.  This is a massive problem and now my comments are all messed up.   This is the same problem that was brought up here, but was not answered.    Any ideas?


How does thermal expansion actually happen on the quantum level?

Classical physics states that when an object is heated, its particles gain kinetic energy, which causes them push away from each other. But on an even smaller level, what is actually happening? I read it somewhere that when an object is heated, its electrons are bombarded by thermal photons. This apparently causes the electrons to gain energy and move to a higher energy state, and a longer orbit. Is this what happens or is there something else happening?