Router cannot see the Ubuntu server VirtualBox on Windows 8
Virtualbox Server/Client topology
Wrap Caption Around TikZ Figure Building where clause based upon parameters My computer only has one USB-C port and I want to connect multiple USB-C devices to it.  I have trawled through Amazon but am amazed that I cannot find a single one. There are many hubs that have USB 3.1 USB-A ports but not USB-C ones.  Is there a limitation in the spec that prevents this being possible? Why do carnivores evolve? If humans can live without consuming other animals, then why do we do it? From a biological point of view, why do we eat meat? I would also extend the question to other animals because many animals are carnivorous: why did carnivory evolve and why do animals eat meat? Can I update an early Airport Time Capsule? Why does Java have an "unreachable statement" compiler error? Start codon AUG also codes for methionine and without start codon translation does not happen. And even the ambiguous codon GUG codes for methionine when it is first. So does this mean that all proteins start with methionine as the first amino acid. I have come across a question about determining possible minimal polynomials for a rank one linear operator and I am wondering if I am using the correct proof method.  I think that the facts needed to solve this problem come from the section on Nilpotent operators from Hoffman and Kunze's "Linear Algebra".     Question: Let $V$ be a vector space of dimension $n$ over the field $F$ and consider a linear operator $T$ on $V$ such that $\mathrm{rank}(T) = 1$.  List all possible minimal polynomials for $T$.   Sketch of Proof:   If $T$ is nilpotent then the minimal polynomial of $T$ is $x^k$ for some $k\leq n$.  So suppose $T$ is not nilpotent, then we can argue that $T$ is diagonalizable based on the fact that $T$ must have one nonzero eigenvalue otherwise it would be nilpotent (I am leaving details of the proof of diagonalization but it is the observation that the characteristic space of the nonzero eigenvalue is the range of T and has dimension $1$).  Thus the minimal polynomial of $T$ is just a linear term $x-c$.    Did I make a mistake assuming that $T$ can have only one nonzero eigenvalue?  Thanks for your help How to get time difference in minutes in PHP How to calculate minute difference between two date-times in PHP? To tell about a guess about a case in the past, why use "would+have+past participle" instead of "must+have+past participle? I have seen this sentence in an article on bbc, which is about how people lived thousands of years ago. &quot;When this Neolithic home was built, it would have had a cosy roof of turf..&quot; When I read it, I got confused. Because the fact seems as a simple past situation or guessing/assumption about something in the past. it simply gives information about a past event, eg &quot;when I was a child, I had a blue toy car. I have been making a lot of research on whether or not this structure &quot;would+have+past participle&quot; could be used instead of the simple past or &quot;must+have+past participle&quot;, but I could not find any satisfying explanation. Almost all grammer contents cover this structure is used when we imagine the opposite of what actually happened in the past eg. &quot;referring to a missed opportunity&quot; (eg. &quot;if you had come to the party, you would have seen Tom.&quot;), But, in this case of this sentence, &quot;type 3 conditional&quot; is irrelevant. It is not an if sentence,  It simply gives information about how this house was like or was probably like when it was built long ago. Just like it would be If and old lady would want to tell about &quot;how she was like when she was a child years ago. she would simply say &quot;when I was a child, I had long curly hair.**. So &quot;when I was a child, I would have had long curly hair.&quot; would be wrong. So, my question is: 1-Does this structure &quot;would+have+past participle&quot; completely replace simple past sentences? or can be it be used instead of simple past? 2- If this structure was simply used because the author was not %100 sure about the fact as it was a long long time ago -so he wanted to make a guess or assumption, why did he not simply use &quot;must+have+past participle&quot; or &quot;it was likely that blah blah&quot; which must be used for guessing or assumptions about past happenings. Would it not have made more sense if it was like: &quot;When this Neolithic home was built, it must have had a cosy roof of turf. Is there always an equilibrium point in space for gravity? For instance, for a two-body system, there will always be a point in-between the two in which the forces of gravity completely cancel, and if I were there then I would experience no net force. I believe there is also a point, or a region, for three body systems as well. Assuming we treat the stars or planets as simply point-masses, will there always be, for any number of objects, a point, or a region, of equilibrium? Or no? Does the force of kinetic friction increase with the relative speed of the objects involved? If not, why not? Does the force of kinetic friction increase with the relative speed of the objects involved?    I have heard and read that the answer is no.  This is counter intuitive, and is a big part of why the "Airplane on a Treadmill" question is so interesting.  What phenomena are at work with kinetic friction, and why does it not increase with relative speed? Why does the Community user have votes cast? If Community is a background process and not a real person then why does its profile show that it has votes cast, and how does it cast them?  How can it decide which answers to upvote or downvote?  See the massive number of upvotes and downvotes cast in its profile: I would like to be able to write a Java class in one package which can access non-public methods of a class in another package without having to make it a subclass of the other class. Is this possible? What is "my guy syndrome" and how do I handle it? I've been reading forum posts and blogs who mention "my guy" syndrome as a specific type of difficult player, but I can't seem to find a solid definition for the term. Can someone explain this particular kind of problem player to me? How do you deal with this kind of problem? File l3backend-pdfmode.def not found when loading expl3 I updated my TeXlive distribution a couple times in the past week, and now I get this error when I include package expl3 (or any other package that includes it, such as fontspec). Before the updates it was working fine. Am I missing any package that should be installed? I tried searching for l3backend-pdfmode.def, but I found no results.  \documentclass{article} \usepackage{expl3} \begin{document} Hi \end{document}   λ lualatex a This is LuaTeX, Version 1.10.0 (TeX Live 2019)   restricted system commands enabled. (./a.tex LaTeX2e &lt;2018-12-01&gt;  luaotfload | main : initialization completed in 0.042 seconds (/opt/texlive/2019/texmf-dist/tex/latex/base/article.cls Document Class: article 2018/09/03 v1.4i Standard LaTeX document class (/opt/texlive/2019/texmf-dist/tex/latex/base/size10.clo)) (/opt/texlive/2019/texmf-dist/tex/latex/l3kernel/expl3.sty (/opt/texlive/2019/texmf-dist/tex/latex/l3kernel/expl3-code.tex)  ! LaTeX Error: File `l3backend-pdfmode.def' not found.  Type X to quit or &lt;RETURN&gt; to proceed, or enter new name. (Default extension: def)  Enter file name:  ! Emergency stop. &lt;read *&gt;   l.282   }   379 words of node memory still in use:    2 hlist, 1 rule, 1 dir, 3 kern, 1 glyph, 4 attribute, 48 glue_spec, 4 attrib ute_list, 1 write nodes    avail lists: 2:9,3:3,4:1,5:2,7:2,9:2 !  ==&gt; Fatal error occurred, no output PDF file produced! Transcript written on a.log. How can I drive 12v LEDs from my Arduino Nano? Background I am building a scale RC helicopter and ordered a bunch of 3mm LEDs to give it some nice navigation and strobe lights which I plan to drive with an Arduino Nano. Problem is that I goofed and didn't notice that the LEDs are 12v until they arrived.  I know that the Arduino Nano can accept 12V on pin 30, but I think the voltage output on any of the &quot;D&quot; or &quot;A&quot; pins is always 5v (correct??). Question If the voltage output of the Arduino pins is 5v, then how can I drive the 12v LEDs using the Arduino, or is it impossible? Regular Expression to match valid dates I'm trying to write a regular expression that validates a date.  The regex needs to match the following   M/D/YYYY MM/DD/YYYY Single digit months can start with a leading zero (eg: 03/12/2008) Single digit days can start with a leading zero (eg: 3/02/2008) CANNOT include February 30 or February 31 (eg: 2/31/2008)   So far I have   ^(([1-9]|1[012])[-/.]([1-9]|[12][0-9]|3[01])[-/.](19|20)\d\d)|((1[012]|0[1-9])(3[01]|2\d|1\d|0[1-9])(19|20)\d\d)|((1[012]|0[1-9])[-/.](3[01]|2\d|1\d|0[1-9])[-/.](19|20)\d\d)$   This matches properly EXCEPT it still includes 2/30/2008 &amp; 2/31/2008.  Does anyone have a better suggestion?  Edit: I found  on RegExLib  ^((((0[13578])|([13578])|(1[02]))[\/](([1-9])|([0-2][0-9])|(3[01])))|(((0[469])|([469])|(11))[\/](([1-9])|([0-2][0-9])|(30)))|((2|02)[\/](([1-9])|([0-2][0-9]))))[\/]\d{4}$|^\d{4}$   It matches all valid months that follow the MM/DD/YYYY format.  Thanks everyone for the help. Is there a program that can make live USBs for any distro, iso, you get the point. I can only find ones that make live USBs for other linux distributions and none for anything else. Make Chrome always execute with flags, for eg., directly opening an HTML file I want to run Chrome with a given set of flags, always  I created a shortcut and added the flag to it in the following way, so my target of the shortcut says:  C:\&lt;application-path&gt;\chrome.exe --user-data-dir=D:\Chrome   But when I double click an HTML file, or if any other application triggers Chrome, it looses the flag value. The result - A new chrome window opens with Default profile directory.  I want to make the flag permanent, so that its active irrespective of however Chrome executes.  I tried changing the following registry key:  HKEY_CLASSES_ROOT\ChromeHTML\shell\open\command   It was this earlier:  "C:\&lt;application-path&gt;\chrome.exe" -- "%1"    I changed to following attempts which did not work:  1. "C:\&lt;application-path&gt;\chrome.exe" -- "%1" --user-data-dir=D:\Chrome 2. "C:\&lt;application-path&gt;\chrome.exe" -- "%1" -- "user-data-dir=D:\Chrome" 3. "C:\&lt;application-path&gt;\chrome.exe" -- "%1 user-data-dir=D:\Chrome"   Conclusively, when I try to open a link from any application, it doesn't open in my current Chrome as a new tab, rather opens a new Chrome window with no plugins and extensions since its from other directory.  Why I have changed my default directory? - because the OS drive was getting low on memory due to heave Chrome caches and apps.