Why do file transfers over USB slow down my whole computer?
System freezes/unresponsive/unusable when copying large file to USB
Do electrons in an electron beam (cathode ray) follow the ? Or in other words, does the Pauli exclusion principle apply for the beam of electrons? A vessel is filled with liquid,3 parts of which are water and 5 parts syrup.How much of the mixture must be drawn off and replaced with water so that the mixture may be half water and half syrup?  What is the best possible way to solve this question? In Ubuntu ISO MBR, why does a GPT partition overlap the boot partition, and make MBR uneditable? How to yield from parallel tasks in .NET 4.5 I've recently updated to Ubuntu 20.04. When English is not the chosen language all shortcuts don't work (such as Ctrl + C, Ctrl + A, etc). It was working fine in the previous versions. What happened and What can I do to fix it? Socket Tester all indicators light up I used the above GFCI/RCD (up to 250v) socket tester on the 240v black and red live wire of the US split phase ac power system. When I connect the ground, all indicator lights (3 red) got on indicating "Live/Grd Reverse, Missing GRD" although it is connected properly.  What is inside the socket tester? Does it have a live and neutral leg such that it should only be used for ac system with polarity? How about if you use it on the red and black 240v phase to phase? Why would all the indicators light become on (3 red lights)?  The following is the specs of it:  Specifications: Brand Name: HABOTEST Color: Black Material: Flame Retardant ABS Plug Type: US Voltage: 48V-250V 45-65Hz RCD Test: >30mA (EU/UK Plug) RCD Working Voltage: 220V±20V GFCI Test: >5mA (US Plug) GFCI Working Voltage: 110V±20V Voltage Measurement: 48V~250V / 45~65Hz    Accuracy: ±(2.0%+2) Working Environment: 0°C ~ 40°C, 20% ~75%RH Storage Environment: -10°C ~ 50°C, 20% ~80%RH Safety Rating: EN61010-1,-2-030, EN61326-1,CAT II 300V Item Size: 62 * 65 * 55mm / 2.4 * 2.6 * 2.2in Item Weight: UK 64g/2.3oz, EU 59g/2.1oz, US 53g / 1.9oz Package Size: 7.5 * 7.4 * 7.3cm / 3.0 * 2.9 * 2.9in Package Weight: UK 90g/3.2oz, EU 86g/3.0oz, US 79g / 2.8oz Which is the simplest way to update a Label from another Thread?   I have a Form running on thread1, and from that I'm starting another thread (thread2).  While thread2 is processing some files I would like to update a Label on the Form with the current status of thread2's work.   How could I do that? Quotient group $SL(2,\mathbb{R})/SO(2,\mathbb{R})$ I am confused by expressions like $\mathbb{R}/\mathbb{Z}$, especially if I see something of the sort $SL(2,\mathbb{R})/SO(2,\mathbb{R})$. I don't know what to make of it. I understand what a quotient of a group for an equivalence looks like, but I can't get my head around expressions like above.   Is a quotient like this always a group and what do elements in the set $SL(2,\mathbb{R})/SO(2,\mathbb{R})$ look like? Proving that $x_n\to L$ implies $|x_n|\to |L|$, and what about the converse? Problem 3. Show that for a sequence $(x_n)$ the following are true:   (i) $\lim x_n=0$ if and only if $\lim |x_n|=0$.   (ii) $\lim x_n=L$ implies $\lim |x_n|=|L|$. Is the converse true? Prove or give a counterexample.    (i) is already done, easy.  I'm halfway done with (ii), I split it into three cases:  $L = 0$, $L &gt; 0$ and $L &lt; 0$.  For $L = 0$ I just refer to part (i).  For $L &gt; 0$, we know that $|x_n - L| &lt; \epsilon$   if lim $|x_n|$ = $|L|$, then we must have  $||x_n| -|L|| &lt; \epsilon$  but by the reverse triangle equality, $||x_n| - |L|| &lt; |x_n - L|$ so clearly $||x_n|-|L|| &lt; \epsilon$, thus  lim $x_n = L$ $\implies$ lim $|x_n| = |L|$ for $L &gt; 0$  for some reason I'm confused as to part three, $L&lt;0$. I'm having trouble seeing the difference between $L&gt;0$ and $L&lt;0$, and i'm starting to think that splitting it up like that isn't necessary at all. Agent Smith, in the first Matrix movie (The Matrix) talks about how the machines originally created a paradise setting and humans didn't accept it, so it went back and created a more realistic one that humans would accept.  The human bodies, as we've seen, are kept in tanks and the body is kept asleep.  But why did the Matrix need to provide any kind of simulation for the brain to experience?  Why couldn't it have just kept all humans in a medically induced coma?  Or performed something equivalent to a lobotomy on every human?  Why did the Matrix need to spend the resources to keep the humans in good mental shape? Can it hurt to put my GRE score on my resume? If my score is good and if I'm applying for an MS program in Europe, can it give me any kind of edge? The university I'm applying to requires GRE scores for certain programs but not the one I'm applying for. And if it won't be advantageous, can it hurt my prospects in anyway? How do I play a sound in Octave? Understanding Dirac's notation How can I show that the order of an element modulo $n$ divides $\phi(n)$?  I know that if $a$ and $n$ are relatively prime, then the least positive integer $x$ such that $a^x\equiv1\pmod n$ is its order modulo $n$. I also know that, by Euler's theorem, $a^{\phi(n)}\equiv1\pmod n$. Therefore, it must be the case that $x\leq\phi(n)$.  However, all that I am left to do is to show that $kx=\phi(n)$, for some integer $k$. Do you guys have an idea on how to do this? Thanks in advance! Is it possible to scale up an image to increase the the pixel density? When should I use # and = in ASP.NET controls? Why is 3D stress tensor acting only on three surfaces? I'm trying to learn about the stress tensor (in 3D)    The tensors are said to have directions (the first subindex $i$ in $\sigma_{ij}$) and specify the surface upon which they act (the second subindex $j$ in $\sigma_{ij}$).  What confuses me is why is it defined only to act on three surfaces, even when the cube has six surfaces? Java FileReader encoding issue I tried to use java.io.FileReader to read some text files and convert them into a string, but I found the result is wrongly encoded and not readable at all.  Here's my environment:   Windows 2003, OS encoding: CP1252 Java 5.0   My files are UTF-8 encoded or CP1252 encoded, and some of them (UTF-8 encoded files)  may contain Chinese (non-Latin) characters.  I use the following code to do my work:     private static String readFileAsString(String filePath)     throws java.io.IOException{         StringBuffer fileData = new StringBuffer(1000);         FileReader reader = new FileReader(filePath);         //System.out.println(reader.getEncoding());         BufferedReader reader = new BufferedReader(reader);         char[] buf = new char[1024];         int numRead=0;         while((numRead=reader.read(buf)) != -1){             String readData = String.valueOf(buf, 0, numRead);             fileData.append(readData);             buf = new char[1024];         }         reader.close();         return fileData.toString();     }   The above code doesn't work. I found the FileReader's encoding is CP1252 even if the text is UTF-8 encoded. But the JavaDoc of java.io.FileReader says that:     The constructors of this class assume   that the default character encoding   and the default byte-buffer size are   appropriate.   Does this mean that I am not required to set character encoding by myself if I am using FileReader? But I did get wrongly encoded data currently, what's the correct way to deal with my situtaion? Thanks. Preserving signatures of decorated functions Suppose I have written a decorator that does something very generic. For example, it might convert all arguments to a specific type, perform logging, implement memoization, etc.  Here is an example:  def args_as_ints(f):     def g(*args, **kwargs):         args = [int(x) for x in args]         kwargs = dict((k, int(v)) for k, v in kwargs.items())         return f(*args, **kwargs)     return g  @args_as_ints def funny_function(x, y, z=3):     """Computes x*y + 2*z"""     return x*y + 2*z  &gt;&gt;&gt; funny_function("3", 4.0, z="5") 22   Everything well so far. There is one problem, however. The decorated function does not retain the documentation of the original function:  &gt;&gt;&gt; help(funny_function) Help on function g in module __main__:  g(*args, **kwargs)   Fortunately, there is a workaround:  def args_as_ints(f):     def g(*args, **kwargs):         args = [int(x) for x in args]         kwargs = dict((k, int(v)) for k, v in kwargs.items())         return f(*args, **kwargs)     g.__name__ = f.__name__     g.__doc__ = f.__doc__     return g  @args_as_ints def funny_function(x, y, z=3):     """Computes x*y + 2*z"""     return x*y + 2*z   This time, the function name and documentation are correct:  &gt;&gt;&gt; help(funny_function) Help on function funny_function in module __main__:  funny_function(*args, **kwargs)     Computes x*y + 2*z   But there is still a problem: the function signature is wrong. The information "*args, **kwargs" is next to useless.  What to do? I can think of two simple but flawed workarounds:  1 -- Include the correct signature in the docstring:  def funny_function(x, y, z=3):     """funny_function(x, y, z=3) -- computes x*y + 2*z"""     return x*y + 2*z   This is bad because of the duplication. The signature will still not be shown properly in automatically generated documentation. It's easy to update the function and forget about changing the docstring, or to make a typo. [And yes, I'm aware of the fact that the docstring already duplicates the function body. Please ignore this; funny_function is just a random example.]  2 -- Not use a decorator, or use a special-purpose decorator for every specific signature:  def funny_functions_decorator(f):     def g(x, y, z=3):         return f(int(x), int(y), z=int(z))     g.__name__ = f.__name__     g.__doc__ = f.__doc__     return g   This works fine for a set of functions that have identical signature, but it's useless in general. As I said in the beginning, I want to be able to use decorators entirely generically.  I'm looking for a solution that is fully general, and automatic.  So the question is: is there a way to edit the decorated function signature after it has been created?  Otherwise, can I write a decorator that extracts the function signature and uses that information instead of "*kwargs, **kwargs" when constructing the decorated function? How do I extract that information? How should I construct the decorated function -- with exec?  Any other approaches? I have a question about making an ending symbol.  It is a LaTex-default that every proof environment has an ending symbol. I want to make every theorem-alike environment such as the example environment have also an ending symbol. But how to manually set this up? Specifically, I want to make all these environments ended by a square symbol.  \newtheorem{thm}{Theorem} \newtheorem{lem}[thm]{Lemma} \newtheorem{cor}[thm]{Corollary} \newtheorem{pro}[thm]{Proposition} \newtheorem{assump}{Assumption} \newtheorem{axiom}{Axiom} \newtheorem*{conj}{Conjecture} \theoremstyle{definition} \newtheorem{defi}[thm]{Definition} \newtheorem{exam}{Example} \newtheorem{exer}{Exercise} \newtheorem*{rem}{Remark} \newtheorem*{notation}{Notation} \newtheorem*{note}{Note}   I am looking for, with gratitude, a comprehensive setup.