According to wikipedia,      A rainbow is an optical and meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets...   Given that we require reflection, refraction and dispersion to take place, I was quite intrigued when I saw that the reflection of light on the TV has scattered into a rainbow.    This is how the light looks like:   Can somebody explain this phenomenon?   Also the shape of the light in the reflection seems interesting, reminds me of interference patterns. I mean the light source is simply circular in shape. Any comments on that?
I was up late working with my red LED headlamp on and when I was looking at the black part of my LCD (Apple Retina Macbook Pro) screen I noticed this interesting diffraction pattern. I'm confused because all I can think of that would cause this are Fourier and Fraunhofer patterns which I thought required more advanced optics the light to be collimated. One friend suggested it might be the polarizer. Any thoughts?  Unfortunately, the picture doesn't show this, but along the x and y axes there were discrete points not a continuous streak. Sorry for the horrible photo quality.
CSV rows to Polyline with OGR I'm not sure if I can complete this operation in one step - but someone might be able to help me.  My input file is a csv file with PointID, x, y, z and LineID columns.  I'm looking to combine all rows with the same LineID into Polyline25D using ogr2ogr with a virtual datasource (VRT file).  I can get a MultiPoint output, but can't work out how to combine multiple rows (if it's at all possible).   Alternatively, could someone help me with a python script to combine the x, y, z fields into WKT?  Input Example :  pointid y   x   z   lineid 1   320589.01   1815258.73  423.78  1 2   320573.49   1815256.71  425.04  1 3   320557.42   1815252.40  425.86  1 4   320541.64   1815248.71  426.19  1 5   320529.37   1815247.01  427.18  1 1   320588.78   1815259.35  423.43  2 2   320573.06   1815257.09  424.66  2 3   320557.00   1815253.09  425.06  2 4   320541.79   1815249.54  425.78  2 5   320529.14   1815247.74  426.22  2 6   320516.78   1815245.02  426.84  2 1   320588.62   1815260.10  423.44  3 2   320572.59   1815258.42  424.65  3 3   320556.21   1815255.29  425.13  3 4   320540.73   1815252.19  425.80  3 5   320529.02   1815248.37  426.20  3 $f(z)$ and $\overline{f(\overline{z})}$ simultaneously holomorphic I want to play a game in an older update, but can't see a way to choose a specific version. Is this possible? How many attacks can a fighter with two-weapon fighting make at 5th level? I have a 5th level fighter with the Two-Weapon Fighting fighting style.   What is the number of attacks I can make?   I say 4 attacks, but others say 3 because they say the rule on page 72 states that I get (only) 1 extra attack. Passive with "to get" In spoken English (at least in America), passives are often formed with "to get" rather than "to be;" I would wager the majority of the time:   he got hit by a car I get driven to work I've gotten called for jury duty eight times   Are there specific verbs that prefer "be" to "get," or vice-versa, or semantic differences between these forms? I cannot think of any. I haven't seen this behavior out in the wild much, but it happened again recently and I was wondering if a flag could be automatically raised when this happens:   User posts answer Answer is down voted User deletes answer User posts exact same text as a new answer User effectively ditched down votes   Got down voted again? Wash, rinse and repeat. Profit (perhaps after modifying the post, which is what you should have done to begin with)    I feel that this should raise a duplicate content flag, with slightly stronger wording. Would this be possible to implement? Or, perhaps, don't let users post new answers if they have a deleted answer to a question. Rather, force them to edit and restore the deleted answer instead, unless locked by a moderator.  I do have a link, but I don't want a lot of people to descend on it and create an even bigger disruption. It happened exactly as I described. Remove items from one list in another How can I have a horizontally shaded frametitle in beamer? This question is similar to . I want to achieve the horizontal shading effect in the frametitle and when I use  \setbeamertemplate{frametitle}[horizontal shading] [left=red, right=white]   I get compilation errors:  LaTeX Error: Missing \begin{document}. [[]   Vertical shading seems to work just fine. Rejecting a PhD offer after having accepted it. Advice? I have accepted a PhD offer from a very good university to do a project very close to my interests. I have told the project supervisor I accept it. In the meanwhile I have managed to secure a PhD offer from another 2 universities much better in world rankings and with better research groups and better faculty. Additionally these 2 universities do research exactly on what I want to devote my PhD research.  My only commitment to the first university is a mail confirming I accept. Nothing else. I understand declining the offer after already having accepted it is quite dishonest but it is a huge decision that will affect my future in a very significant level.   I would like your opinion and I would also like to ask for possible consequences of such an action. As far a postdocs concerned, in the first university there is no chance I ever get a postdoc since they do not actually do research on my area (except for the prospective supervisor and even he not as much).  UPDATE I have decided to do as I was afraid to. I have decided to choose a different university than the first one that I have already accepted the offer. My offer acceptance included:    An online "I accept" statement. An e-mail I sent stating "I accept the scholarship and this University is my first option"   I do not have any legal commitments since I have not signed anything. The supervisor of the first university though is really nice to me and continuously was sending me mails. How do I very nicely tell her I will not be joining in the end? Additionally the place I will go in the end will be for research in Mathematics and not Physics. Can I use this as a part of a sensical excuse?  WHAT I HAVE CHOSEN AND WHAT THE CONSEQUENCES WERE  I think that I should let people, especially other beginning grad students know what happened with my case. I have chosen to nicely tell the first university I got accepted that I will not be attending and will not be pursuing a PhD there since I decided I have different research interests (which is true). I had applied there in the first place since I was not sure what I wanted to do and because it was a nice program. Despite that, I got an offer from a World top university to work on 100% my research interests. I explained this to them, the first uni, and they happily let me go and wished me good luck, especially the supervisor who faught a lot secure me funding. I was lucky. Is causality a formalised concept in physics? I use Internet Explorer for some things and Chrome for others. I'd like to have a choice when I click on a link of which browser to open the link in. Is this possible in Windows? I am currently running Windows 8, although there should be similarities between versions.  To the best of my knowledge this isn't possible. Should I include a link to my Stack Overflow profile on my résumé? Using "nor" in a list without "neither" This is the classic usage of neither/nor:     I would neither hide nor run away.   But is the following construction grammatical? (More than two choices, no neither)     I wasn't going to play dead.   I wasn't going to hide.   Nor was I going to run away. PayPal API Listener Website Payments Standard URI I have a Sharepoint online page on which I would like to remove the blue navigation bar at the very top of the screen (the one with the seach bar in the middle and the button on the left with 9 dots to switch to different Microsoft apps). I have checked all of the header settings and also went into the site settings and modified the search settings. I was able to exclude the site from search results, however the blue bar still remains. Is this possible to remove in a default SharePoint online site without using custom CSS or anything like that? I just came onto a project with a pretty huge code base.   I'm mostly dealing with C++ and a lot of the code they write uses double negation for their boolean logic.    if (!!variable &amp;&amp; (!!api.lookup("some-string"))) {        do_some_stuff();  }                                      I know these guys are intelligent programmers, it's obvious they aren't doing this by accident.   I'm no seasoned C++ expert, my only guess at why they are doing this is that they want to make absolutely positive that the value being evaluated is the actual boolean representation. So they negate it, then negate that again to get it back to its actual boolean value.   Is this correct, or am I missing something? I've got a very small coefficient (-0.04) and R-squared (0.028) but a significant P value (&lt;0.0001). My question is:   Is my result still meaningful? How to interpret it?   The result is from a linear regression model in a big database in R.  The independent variable (B) has more than 200 values, whereas the dependent variable (A) has 13 values.   The potential correlation is below:   So, I ran a linear regression model between A and B and the result is:  &gt;mod1&lt;-lm(A~B)          Call:         lm(formula = A ~ B)           Residuals:              Min      1Q  Median      3Q     Max           -63.174 -11.816  -1.651  10.184 118.001            Coefficients:                        Estimate Std. Error t value Pr(&gt;|t|)              (Intercept) 132.274547   0.303723 435.511  &lt; 2e-16 ***          B            -0.036675   0.009052  -4.052 5.13e-05 ***          ---         Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1          Residual standard error: 18.52 on 8093 degrees of freedom            (123 observations deleted due to missingness)         Multiple R-squared:  0.002024,  Adjusted R-squared:  0.001901          F-statistic: 16.42 on 1 and 8093 DF,  p-value: 5.134e-05   As you can see, the coefficient of B is only -0.03 and adjusted R squared is only 0.1% but with a p value &lt;0.0001. Is my result reasonable and countable? Surely, my database is larger (8000 records) and even a very small effect size will show a significant P value. But how would I interpret this? CDF of absolute value of difference in random variables Adding items to page template dropdown on Page Edit Screen I am developing a WP theme with MVC approach. It only have index.php, functions.php and styles.css on the parent directory. So, I do not want to place page templates on it rather then I want to programmatically provide them from View classes while functionality from edit screen stays the same.   Users need to have page templates select option on the edit screen. How do I successfully add Items to the template dropdown?  I tried to hook into  filter.   Example code:  add_filter( 'theme_page_templates', function($templates){      $templates['my-page-template.php'] = "My Page Template";      return $templates;  });   This does not work because of the use of  on the filtered array, which removes the added page template item. I don't understand why this function is used. It seems you can only remove page template from the list but can not add a new one using the given filter.  Is there any other way around? What do you call something that is not first in a sequence? Is there a word to describe something that is not the first element in a sequence, but can be in any other position? A synonym of "not first", in fact.     This element is __ in this sequence.