Odd behaviour of python's class
"Least Astonishment" and the Mutable Default Argument
is it possible to raise the tip while raising the back and lowering the center of the tongue when making /R/ sound? Following , this is how we correctly make the r sound:   Let the throat vibrate since it is voiced. Round the lip a little. Raise the tip of the tongue towards the hard bump behind the upper front teeth,  but do not let the tip of tongue touch the bump. This also makes the center of the tongue go down. The back part of the tongue is raised because you pull it into a tight ball Fold and raise the sides of the tongue so they touch the upper side-teeth.   If we follow the above requirement, our tongue should have an s shape when we pronounce the r sound as depicted in the following sketch:    Is it possible to raise the tip while raising the back and lowering the center of the tongue when making an r sound?   How do native speakers make an r?  P.S. My tongue is very short anyway! Who wrote about an energy free space elevator? How to generate XML file dynamically using PHP? I have to generate a xml file dynamically at runtime. Please help me in generating the below XML file dynamically using PHP.  &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;xml&gt;  &lt;track&gt;      &lt;path&gt;song1.mp3&lt;/path&gt;      &lt;title&gt;Track 1 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song2.mp3&lt;/path&gt;      &lt;title&gt;Track 2 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song3.mp3&lt;/path&gt;      &lt;title&gt;Track 3 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song4.mp3&lt;/path&gt;      &lt;title&gt;Track 4 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song5.mp3&lt;/path&gt;      &lt;title&gt;Track 5 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song6.mp3&lt;/path&gt;      &lt;title&gt;Track 6 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song7.mp3&lt;/path&gt;      &lt;title&gt;Track 7 - Track Title&lt;/title&gt;  &lt;/track&gt;  &lt;track&gt;      &lt;path&gt;song8.mp3&lt;/path&gt;      &lt;title&gt;Track 8 - Track Title&lt;/title&gt;  &lt;/track&gt; If i entered "name" in my text box while it saved it must be saved like "Name"   Capital letters in the first letter of Alphabet  It must not show any error messages it must directly save Why is the \bf command applied to more than I asked? MWE:  \documentclass{article}  \usepackage{bm}  \begin{document} $$x(t), \bf{x}(t), \bf{x(t)}$$ \end{document}   Result:    Question:  Why are the second and third x(t) typeset the same? In the second  expression, it was asked to apply \bf to only x.  EDIT:  I had not payed attention to it when asking the question, but I would like to have a bold and italic x. I asked a  recently, looking for examples of an online tool. Per the , I answered my own question with a few examples that I had already found. I did this so that these examples would be included in the answers, along with the rest.  The question has received only down votes and insults saying that this shouldn't be done.   Should I not answer my own questions? why is nautilus slow? I'm wondering why Nautilus is very slow when opening a directory containing lots of files. My /usr/lib dir for example has 1900 files and it takes approximately 5+ seconds to show everything. It has been like this since I installed Ubuntu few months ago and it's really quite annoying sometimes. I don't have powerful hardware but I know that Windows Explorer is so much faster than this.   Is there anything that can be done to speed it up?  Ubuntu 10.04 Summer in Saint Helena The Winter Bash site is located at http://winterba.sh/.  Only one problem:   . Saint Helena is in the Southern Hemisphere. It's Summer in Saint Helena.   So shouldn't it be the Summer Bash? Don't forget our Aussie/Kiwi/South African/Southern Brazilian/Argentine/Uruguayan/Zimbabwean/Swazi/Tokelauan/Tuvaluan/Pitcairn Islander/ friends! In swimming, is there a competitive advantage to being in one lane or another? Upon observing swimming competitions in the Olympics, it is not clear to me whether one of the eight lanes is more advantageous versus another. I've seen vague claims but nothing backed up with science.  In competitive swimming, is there an advantage to being in one lane or another? Furthermore, does the stroke (ie: breast, fly, freestyle, etc.) affect this effect? Comparison between bootstrap percentiles confidence interval and BCa confidence interval? I have generated a nonparametric percentiles bootstrap confidence interval ($32.27143, 51.08571$), and a BCA confidence interval ($33.26, 53.49$) with an initial sample size of $n=7$.  Evidently, the BCA interval is larger than the percentiles interval. Shouldn't the BCA interval be better than the percentiles interval (and by "better" I mean "smaller")? I noticed also that when the sample size is larger, for example $n=40$, BCa confidence interval decreases. What is the best way to execute a script when entering into a directory? When I move into a new directory I would like bash to execute the projectSettings.bash script much like RVM does. Can "zero hours contracts" be considered as not grammatical? When speaking with my mother a couple of days ago, I read to her a message I was sending to my cousin on her behalf ending with: "... the birthday of your youngest." [implying her child]  She immediately leapt on this and said that as my cousin only had two children, the use of the superlative was not permitted and the comparative must be used instead: "... the birthday of your younger child."  She was adamant that this was a solid grammatical rule that she was taught throughout her education.  As a younger Briton, I have relatively little formal grammatical education to older people who were better taught in this regard, so I usually defer to her on grammatical rule knowledge.  Is she right?  Are superlatives not permitted when the domain of the object is only two?  To me it seems bizarre.  The minimum or maximum of any set does not only exist when there are different minima and maxima, or indeed something which is neither. JavaScript equivalent to printf/String.Format I'm looking for a good JavaScript equivalent of the C/PHP printf() or for C#/Java programmers, String.Format() (IFormatProvider for .NET).  My basic requirement is a thousand separator format for numbers for now, but something that handles lots of combinations (including dates) would be good.  I realize Microsoft's  library provides a version of String.Format(), but we don't want the entire overhead of that framework. How are the number of views in a question calculated? I saw it's not just a page views number, because, if I press F5 several times, it won't increase the number of views.  They could store my IP address in a table, but wouldn't that make it slow? They would need to query a database one more time for each request. Product of manifolds & orientability I'm studying orientability of manifolds currently and I'm having trouble to prove the following: $M\times N$ is orientable iff $M$ and $N$ are orientable.   I am able to prove that the product is orientable if components are orientable (chart is $\{(U_\alpha\times V_{\beta},\phi_\alpha\times \psi_\beta):(\alpha,\beta)\in A\times B \}$, and $\det J=\det J_1 \det J_2&gt;0$ by Cauchy-Binet's theorem), but I don't know how to prove the other direction.   So why this holds: if $M\times N$ is orientable, then $M$ and $N$ are orientable?  Thanks in advance. If mastery of the Force is hereditary, how are the Jedi so numerous? Will my Chinese visa still be valid if I renew my passport? If so how does that work?  I have heard that you can travel with your new passport and just show the old passport with the valid visa when entering China. Has anyone done that? Recently?   I have also been told that you have to get a new visa, which seems somewhat logical but frustrating, especially when my Chinese visa is only a few months old.  My Chinese visa was issued in late Nov 2014 and I heard the rules changed between the US and China. My visa says it's good for 10 years and my US passport expires in 5. I am fascinated by the way the CLR and GC works (I'm working on expanding my knowledge on this by reading CLR via C#, Jon Skeet's books/posts, and more).  Anyway, what is the difference between saying:  MyClass myclass = new MyClass(); myclass = null;   Or, by making MyClass implement IDisposable and a destructor and calling Dispose()?  Also, if I have a code block with a using statement (eg below), if I step through the code and exit the using block, is the object disposed of then or when a garbage collection occurs? What would happen if I call Dispose() in the using block anyay?  using (MyDisposableObj mydispobj = new MyDisposableObj()) {  }   Stream classes (eg BinaryWriter) have a Finalize method? Why would I want to use that? Word for two collections that do not have any elements in common