Why is frosted glass reflective at an angle? I have a Pixel 3, and the back of the phone is frosted glass. I noticed today that if I look at the back from a wide angle it becomes reflective, whereas it is opaque when looking directly on.  What causes this phenomenon?
Why is there a clear mirror image off a rough surface at shallow angles? The mirrors we use everyday have a highly reflective smooth surface, so that we can see a clear image.  But I found the same happens on a rough (not so smooth) surface, though only at shallow angles.  For example    this is the logo of physics stackexchange, reflected from the back of an ipad.  Considering that aluminum may contributed to reflection, I tried a different material:    this time a piece of printer paper.  Though not as clear, there is still some visible pattern resembling the logo.  The same effect can be observed on highways, where distant vehicles have a mirror image off the road; I do not have a picture at hand however.  So, why is this happening, and why only on shallow angles?
What is the difference between a function decorated with  and one decorated with ? What can I do if I forgot my Windows password? Proving a Composition of Functions is Bijective If I have $f:\mathbb{R}\rightarrow\mathbb{R}$ such that $f$ is onto and $f\circ f\circ f = f$, how can I prove that $f$ is bijective? I know that I only have to prove that it is 1-to-1 because I'm given the fact that it's onto, but how can I use the fact that $f\circ f\circ f=f$ to prove that it is 1-to-1?  Thanks! Word: how to show hidden ribbon tabs? How can I control which tabs are available to be opened in the MS Word 2010 ribbon?  Under Word Options > Customize Ribbon > Main Tabs there are several groups checked (Blog Post, Insert (Blog Post), Outlining, Background Removal), but they don't appear on the ribbon even though there is space for them. How is one supposed to turn them on or get to them?  The one in particular I'm after today is the Blog Post tab, which I know I can get to in a round about way via File > New > Blog Post Template. However I don't want a new post, rather an old one, which means File > New > Blog Post Template > Open existing > [select from list] > [close new blog post window] > [slap No I don't to save darn it]. Extra work for nothing is irritating; how do I get Blog Post (or Outlining or ...) to show up in that nice empty space next to AddIns? Continuous bijection from $(0,1)$ to $[0,1]$ Does there exist a continuous bijection from $(0,1)$ to $[0,1]$? Of course the map should not be a proper map. My daughter bought a ticket for a flight with a layover in Emirates (from Dallas, Texas to India). She had a stop of 48 hours in Dubai. When she was checking in in Dubai for Delhi, she was informed that her visa for India has expired in 2012. Did Emirates not have an obligation to check the visa for India before selling a ticket? I'm having exactly the same issue as , also using Biber 2.14, albeit I didn't upgrade, downgrade, change TexLive version, change encoding or (seemingly) do anything. It's like Biber suddenly quit parsing dates on me.  Whether the bibfile is encoded in ASCII or UTF-8 makes no difference. Whether the date is a short format or the full YYYY-MM-DD makes no difference. I'm not sure what else to test.  Here's a MWE and the associated .blg file:  \begin{filecontents}{mwe.bib}     @Article{JD2020,         author       = {John Doe},         title        = {A Title},         date         = {2020-01-01},         %date       = {2020}         journaltitle = {Journal},     } \end{filecontents}  \documentclass{article} \usepackage{biblatex} \addbibresource{mwe.bib}  \begin{document}     test\autocite{JD2020}     \printbibliography \end{document}   [1] Config.pm:304&gt; INFO - This is Biber 2.14 [1] Config.pm:307&gt; INFO - Logfile is 'mwe.blg' [154] biber-darwin:322&gt; INFO - === Thu Apr 30, 2020, 11:04:33 [185] Biber.pm:415&gt; INFO - Reading 'mwe.bcf' [354] Biber.pm:943&gt; INFO - Found 1 citekeys in bib section 0 [384] Biber.pm:4256&gt; INFO - Processing section 0 [385] Utils.pm:75&gt; INFO - Globbing data source 'mwe.bib' [385] Utils.pm:91&gt; INFO - Globbed data source 'mwe.bib' to mwe.bib [401] Biber.pm:4455&gt; INFO - Looking for bibtex format file 'mwe.bib' for section 0 [402] bibtex.pm:1653&gt; INFO - LaTeX decoding ... [406] bibtex.pm:1471&gt; INFO - Found BibTeX data source 'mwe.bib' [437] Utils.pm:304&gt; WARN - Entry 'JD2020' (mwe.bib): Invalid format '2020-01-01' of date field 'date' - ignoring [457] UCollate.pm:68&gt; INFO - Overriding locale 'en-US' defaults 'normalization = NFD' with 'normalization = prenormalized' [457] UCollate.pm:68&gt; INFO - Overriding locale 'en-US' defaults 'variable = shifted' with 'variable = non-ignorable' [457] Biber.pm:4084&gt; INFO - Sorting list 'nty/global//global/global' of type 'entry' with template 'nty' and locale 'en-US' [457] Biber.pm:4090&gt; INFO - No sort tailoring available for locale 'en-US' [461] bbl.pm:652&gt; INFO - Writing 'mwe.bbl' with encoding 'UTF-8' [463] bbl.pm:755&gt; INFO - Output to mwe.bbl [463] Biber.pm:128&gt; INFO - WARNINGS: 1   The \printbibliography output actually looks like this: [1] John Doe. “A Title”. In: Journal ().  In my actual thesis, all the dates are gone from the pdf output. geometry package - paperwidth and paperheight aren't accurate recognize this simple example:  \documentclass[]{article} \usepackage[paperwidth=612.0pt, paperheight=792.0pt]{geometry}  \begin{document} Hello World \end{document}   I compiled it with pdflatex. Additionally I wrote this small Java-Programm (using the iText library):  PdfReader reader = new PdfReader("example.pdf"); Rectangle psize = reader.getPageSize(1); System.out.println(psize.getHeight()); System.out.println(psize.getWidth());   The result:  Height: 789.041 Width: 609.714   Why is the paperwidth and paperheight different to the tex? I have a complex embedded Linux software running on a gentoo derivative, on which a certain piece of code gets executed regularly every ~84 minutes. Sweeping through the main code to find places where this code might get executed was unsuccessful, and crontab also seems no possible explanation.   My question: Is it possible, by modifying the code in question, to find out which other process/code/file/service started it in the first place? Are there some information in the /proc directory I can use? Or is it impossible to find out the process that executed the given code? I am compiling LaTeX files with Texmaker on Ubuntu 12.04 system.   When I run pdflatex and then view the pdf file (internal), it does not show me the exact place where I am editing on Texmaker i.e. the generated pdf file does not show me the position of the cursor.   But some days before it was working fine. I don't know what causes this problem.  I already tried uninstalling and then reinstalling, I did update and upgrade too. But the problem still persists. bash is not terminating I'm trying some things with my shell. This includes the following command:  kill $$  My expectation was that the shell would log me out and terminate itself. But instead the bash persists without change.   Any idea why?  I ran this command on different environments (archlinux, debian). The behavior was always the same. What is the need of complex functions in wave analysis? It is commonly known that waves can be express in terms of sine or cosine function. But when I study further, I seen that for analyising the waves, it is common to use complex functions in the form $$y=y_{_0}e^{i(kx-\omega{t})}$$ where $y_{_0}$ is the amplitude, $k$ is the wave number, $\omega$ is the angular velocity and $x$ &amp; $t$ are position an time respectively. Ofcourse, I know that the function $e^{ix}$ can be written in the form $\cos{x}+i\sin{x}$ and so it is a periodic function with period $2\pi$ but my question is for what purpose we define it in terms of complex numbers? It seem to be more convenient to use real functions for real variables such as amplitude, electric and magnetic field of an electro magnetic wave, and also in quantum mechanics. What actually this interpretation means or what is the advantage of such functions? Are there critical hits for spells? According to PHB p. 194 you always score a critical hit on any attack roll.  Does this rule also apply to magical attacks, e.g. the  spell? How to disable GNOME keyring? I want to disable GNOME keyring globally on my machine. So I deleted the lines  auth    optional        pam_gnome_keyring.so session optional        pam_gnome_keyring.so auto_start   in /etc/pam.d/gdm. It seems to me that this has no effect. When I lock in the syslog writes  Aug 24 18:37:03 foobar gnome-screensaver-dialog: gkr-pam: unlocked login keyring   and another user sees a menu window where he hs to enter his credentials. So what is the correct way to disable keyring for every user on that machine? Bluetooth disappeared in Windows 10 I have a Lenovo G580 laptop. In the past, using Windows 8, I could use Bluetooth to connect to other devices.  Installing Windows&nbsp;10, Bluetooth simply disappeared. I can't find anything related to Bluetooth in the Device Manager, also in Settings → Devices.  There is no Windows&nbsp;10 Bluetooth driver for my laptop.  What can I do? How strong is Superman on Krypton? When Superman goes back to visit his home planet (using his ability to travel through time, I guess), is he:    an exceptionally strong and athletic Kryptonian? just an average Kryptonian male? a weakling on account of spending a lifetime in the comparative microgravity of Earth?   A possibly related question: why is Superman so muscular? What kind of weights does he lift to stay in shape?  The answers to  are all about Superman's superpowers on Earth compared with other visitors from Krypton; I'm asking about Kal El without his superpowers.  Clarification: I'm asking about the "classic"  Superman, say late Golden to early Silver Age, roughly 1945-1960. (Yes, I know the concept evolved during those years.) I'm not sure what that would be in terms of "numbered Earths", those came along after my time. I'm pretty sure the Kryptonians of that era had no superpowers in their native milieu, nor would Kal El if he were deported in space-time to his native world. How are cellphone IP addresses assigned? I have a list/queue of 200 commands that I need to run in a shell on a Linux server.   I only want to have a maximum of 10 processes running (from the queue) at once. Some processes will take a few seconds to complete, other processes will take much longer.   When a process finishes I want the next command to be "popped" from the queue and executed.  Does anyone have code to solve this problem?  Further elaboration:  There's 200 pieces of work that need to be done, in a queue of some sort. I want to have at most 10 pieces of work going on at once. When a thread finishes a piece of work it should ask the queue for the next piece of work. If there's no more work in the queue, the thread should die. When all the threads have died it means all the work has been done.  The actual problem I'm trying to solve is using imapsync to synchronize 200 mailboxes from an old mail server to a new mail server. Some users have large mailboxes and take a long time tto sync, others have very small mailboxes and sync quickly. In the digital age of photography, we can see a range of digital camera sensors sizes in use, from 1/3.2" in small phones, up to Medium format sensors that are 53.4 x 40.0mm in size or more!  Why has no company endevoured to produce a sensor that can be considered to be large format (50mm X 80mm or larger)? Do such camera sensors exist in non-consumer products? Countdowntimer in minutes and seconds