Sum of two closed sets in $\mathbb R$ is closed?

Is there a counterexample for the claim in the question subject, that a sum of two closed sets in $\mathbb R$ is closed? If not, how can we prove it?  (By sum of sets $X+Y$ I mean the set of all sums $x+y$ where $x$ is in $X$ and $y$ is in $Y$)  Thanks!


Where are the pristine, untouched contents of a ~/.profile file?

Several files in my home directory have been disappearing. E.g. .bashrc, .bash_profile, authorized_keys and now .profile.  Regardless of how this happened, I would like to restore the original pristine .profile file. If I create a new user on my system one is created. Where can I find this .profile contents from a fresh, untouched install?


For a foreigner, the usage of 'In + time' and 'after + time' are kind of confusing..   The system will be turned off in 5 minutes.  The system will be turned off after 5 minutes.   I'm confused because many translations in my language are just the same.  Based on my research and study, 1) is right. But I want to make sure.   In a dictionary, IN means after a particular length of time.   (F.Y.I) I want to mean that... like... the system will be turned off when 1min, 2min, 3min, 4min...has elapsed and (finally) 5min ! = the system shutdowns.   And if possible, could you explain what the difference is between them?


How do we solve quadratic congruences such as $X^2+ 3X \equiv -5 \mod{7}$?

How do we solve quadratic congruences such as: $$ X^2+ 3X \equiv -5 \mod{7} $$


Dialog list adapter crashes on NullPointerException

Im trying to adapt list view to an alertDialog, the program crashes on dialog.setAdapter with NullPointerException.   The alertDialog should pop when user is clicking on item in listview.  ArrayAdapter<String> dialogAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, userFunc);     lv.setAdapter(dialogAdapter);      listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {         @Override         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {               if (position == 0) {                   AlertDialog.Builder alertDialog = new AlertDialog.Builder(ManagerFunctions.this);                 LayoutInflater inflater = getLayoutInflater();                 View convertView = (View) inflater.inflate(R.layout.user_op_list, null);                 alertDialog.setView(convertView);                 alertDialog.setTitle("Choose option");                 lv = (ListView) convertView.findViewById(R.id.lv);                  alertDialog.show();   This line is the one I'm getting error on:          lv.setAdapter(dialogAdapter);


Cont. Dividing chapters into ch. 1, ch. 2a, ch. 2b, ch. 3 etc

I want to divide my chapters into sub chapters in same fashion as described in this question:   However I am not getting correct results. while Chapter name/counts are fine, subsections are incorrectly numbered.  Consider the modified file as provided in the accepted answer to above question:  \documentclass{report} \usepackage{etoolbox}% http://ctan.org/pkg/etoolbox %\usepackage{hyperref}% http://ctan.org/pkg/hyperref \newcounter{subchapter}\renewcommand{\thesubchapter}{\alph{subchapter}} \makeatletter % \patchcmd{<cmd>}{<search>}{<replace>}{<success>}{<failure>} \newcommand{\updatechaptercounter}{} \patchcmd{\@chapter}{\@afterheading}{\updatechaptercounter\@afterheading}{}{}% Regular patch of \@chapter %\patchcmd{\Hy@org@chapter}{\@afterheading}{\updatechaptercounter\@afterheading}{}{}% Hyperref patch of \@chapter \makeatother \providecommand{\theHchapter}{}% \newcommand{\startsubchapters}{%   \setcounter{subchapter}{0}% Reset sub-chapter numbering   \renewcommand{\thechapter}{\arabic{chapter}\thesubchapter}% Update chapter number display   \renewcommand{\theHchapter}{\arabic{chapter}\thesubchapter}% Update chapter number display (for hyperref)   \renewcommand{\updatechaptercounter}{\addtocounter{chapter}{-1}}% Update chapter number   \let\oldchapter\chapter%   \renewcommand{\chapter}{\stepcounter{subchapter}\oldchapter}% Increment subchapter } \newcommand{\stopsubchapters}{%   \renewcommand{\thechapter}{\arabic{chapter}}% Reset chapter numbering   \renewcommand{\theHchapter}{\arabic{chapter}}% Reset chapter numbering (for hyperref)   \let\chapter\oldchapter% Restore regular \chapter command   \renewcommand{\updatechaptercounter}{}% Clear chapter counter update   \stepcounter{chapter}% Update chapter counter } \begin{document} \tableofcontents \chapter{First chapter} \section{one one} \section{one two} \startsubchapters \chapter{Second sub-chapter} \section{2 A one} \section{2 A two} \chapter{Second sub-chapter} \section{2 B one} \section{2 B two}  \stopsubchapters \chapter{Third chapter} \chapter{Fourth chapter} \end{document}   (I just added sections nothing more)  Provides me with following output:  It should be section 2A.1, 2B.1 etc. instead of 1A.1 1B.1 etc. What am I doing wrong?  (compiled using pdfTeX 3.14159265-2.6-1.40.17 (TeX Live 2016/W32TeX), on windows)


I am currently thinking of doing an experiment for science fair involving time dilation which will use the equations for both time dilation based off of speed and for gravitational dilation to determine if there is a speed and orbit altitude a satellite can maintain to nullify the effects of time dilation.  From the sources I have looked at, satellites gain about an extra 1.7-1.9 seconds every century because they are not effected by gravitational time dilation as much as us on earth. What I need a little help with is finding the equation for gravitational time dilation.  I have found out how to do it for velocity, which was pretty straightforward with the Lorentz equation and finding gamma. Is there a different formula for an orbiting object as opposed to an object on the surface.  Any response would be appreciated and thanks for taking the time to read this.  Original question:


Open Command Prompt in Folder via Rightclick

So I've bought a Win10 laptop and I find myself using the command prompt frequently - in different folders. At first, I just put 1-line batch scripts everywhere to start the Prompt in that folder, but it was repetetive and not really worth it too much.  I remember (perhaps falsely) that I could right-click on a folder and an option "Open Command Prompt in This Folder" would appear. Is there a way to have that available in Windows 10?


How can I use align inside itemize without a newline?

I would like to use align inside of itemize as an item, but without a newline. How can I do this?  MWE  \documentclass[a5paper]{scrartcl} \usepackage{amssymb, amsmath} % needed for math \usepackage[utf8]{inputenc} % this is needed for umlauts \usepackage[ngerman]{babel} % this is needed for umlauts \usepackage[T1]{fontenc}    % this is needed for correct output of umlauts in pdf \usepackage{geometry} \begin{document} \begin{itemize}     \item ba dfasdfasd sadf     \item asdfa sd $x^2$ asdfasdf     \item \begin{align*}                 x^2 + 2x -10 &= 31\\             \Leftrightarrow x^2 +2x + 21 &= 0\\             \Leftrightarrow (x+1)^2+20 &= 0           \end{align*}     \item adfasd asdfas \end{itemize} \end{document}   Results in:    It seems to me that there is also a newline after align or at least more whitespace than there should be. If it is possible, I would like to remove that, too.


Today, comparing processors is obviously not just looking at the frequency and the number of cores.  When choosing a new PC, how do you compare processors? Is there some resource, like a site or something that does (not necessarily super-precise) processor comparisons?  Thanks.


How to change -10;10V sine wave to 0;3.3V dor ADC

I want to build very easy circuit to change -10;10V sine wave to 0;3.3 for ADC in my MCU. I know that I must  reduce the amplitude and change offset.   This circuit would be perfect (Output: 0-3,33V), but I have only 3,3V source (from MCU) and I made another circuit (in which I have output: 0,04-2,83V):    What should I change in second circuit to have output (0-3,3V) like in first circuit? Maybe voltage stabilizer diode or op-amp? Thanks   For those who would searching the same info to their project: I chose first circuit from this post.  I changed R11 to 110K and R12 to 22K,  In place of 2V source I put 2V voltage stabilizer (Sanyo LA5002) (between the 3.3V MCU output and R11). And it work great :)


Wifi is not working. I have a laptp Hp with RTL8723BE. It says *-network UNCLAIMED

I have updated the Ubuntu version to 16.04. Also I've tried a bunch of different solutions as those answering these questions for example:         And none of them has worked. Please, if someone can help I'll appreciate it a lot.  The network command  sudo lshw -C network :  *-network                   description: Ethernet interface    product: RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller    vendor: Realtek Semiconductor Co., Ltd.    physical id: 0    bus info: pci@0000:08:00.0    logical name: enp8s0    version: 07    serial: 3c:a8:2a:7b:fb:8c    size: 100Mbit/s    capacity: 100Mbit/s    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8106e-1_0.0.1 06/29/12 ip=192.168.1.47 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s    resources: irq:41 ioport:4000(size=256) memory:b2600000-b2600fff memory:b2400000-b2403fff *-network UNCLAIMED        description: Network controller        product: RTL8723BE PCIe Wireless Network Adapter        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:09:00.0        version: 00        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: latency=0        resources: ioport:3000(size=256) memory:b2500000-b2503fff   The lspci | grep -i network command :  09:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter


Read all of Lucifer's story from his spin off on Sandman?

I would like to read Lucifer's story from the very beginning which I know started in a Sandman comic book issue. Which are the Sandman comics that involve Lucifer and after that do I read the books?? A little guidance would be helpful


Bracket problems when splitting multiline equations

Basically, I have the following latex code:  \begin{align*} + \left(    \left[ \sum_i y_i x_i(r) - \frac{1}{n}\sum_i y_i \sum_i x_i(r) \right]  \left[  \sum_i x_i^2(r) - \frac{1}{n} \left( \sum_i x_i(r)\right)^2\right]^{-2}  \left[ \sum_i \frac{d^2 x^2_i(r)}{dr^2} -  \frac{2}{n} \left[  \left( \sum_i \frac{d x^2_i(r)}{dr}  \right)^2 + \left( \sum_i x_i(r)\right) \left( \sum_i \frac{d^2 x_i(r)}{dr^2}\right) \right]\right]   \right) \\ \;\;\;) \end{align*}   The problem is that this is too long to fit in one line. However, if I split it, an error occurs saying that there is no \right) to match the \left( on the same line.   I tried breqn. It didnt work at all.   Please help me out, as I am very tired of getting errors.


Find which files are affected by bad blocks on ext4 filesystem

I have an ext4 filesystem that recently developed some bad sectors.  Running fsck.ext4 -c finds and remembers the bad blocks.  How can I find which files (if any) included these bad blocks so I can restore them from backups?


Arrangements of MISSISSIPPI with all S's and P's separated

If the all S,P are separated in the word MISSISSIPPI then the total possible arrangements are $k\frac {10!}{4!.4!} $ then value of k is? Now all S,P are separated so we can have slash method. Thus they can be placed alternatively in $6! $ ways and rest 5 can be placed in $5! $ ways. Thus we equate to get $$6!.5!=k\frac {10!}{4!.4!} $$  to get $k=13.7$ while $k=4/3$ .Where is my mistake Thanks


Find the prime factor decomposition of $100!$ and determine how many zeros terminates the representation of that number.   Actually, I know a way to solve this, but even if it is very large and cumbersome, and would like to know if you have an easier way, or if I am applying wrong. Setting by $\left[\frac{b}a \right]$ the quotient of $b$ with $a$, we have too $E_p(m)$ the largest exponent power $p$ dividing $m$, and found the demonstration of a theorem that says (that in my text says it was discovered that Lagendre) $$E_p(n!)=\left[\frac{n}p \right]+\left[\frac{n}{p^2} \right]+\left[\frac{n}{p^3} \right]+\;...$$always remembering that there will be a number $s$ such that $p^s\geq n!$ which tells us that $$\left[\frac{n!}{p^s} \right]=0$$ thus making the sum of a finite $E_p(n!)$. So that I can address the first question I asked, really have to get all the cousins $(p_1,p_2,...,p_k)$ and make all $$E_{p_1},\;E_{p_2},\;E_{p_3},\;...,\;E_{p_k}$$ with $p$ and cousin $1<p<100$. And to find the zeros have to see how we both exponents in numbers 5 and 2.     Example $$10!=2^83^45^27\\p<10\\E_2(10!)=5+2+1=8\\E_3(10!)=3+1=4\\E_5(10!)=2\\E_7(10!)=1\\$$


Why is independence of observations an assumption in logistic regression

I am currently learning about the assumptions of logistic regression and am having a hard time wrapping my head around why independence of observations is necessary for this test. Any guidance would be appreciated.


I am trying to write a generic equality comparer. I've written the following code.  public static bool Equals<T>(T t1, T t2) {     bool result;     if (typeof(T).IsPrimitive)     {         result = t1 == t2;     }     else     {         if (t1 == null)         {             result = t2 == null;         }         else         {             result = t1.Equals(t2);         }     }     return result; }   However due to the compile error Operator '==' cannot be applied to operands of type 'T' and 'T' for the line result = t1 == t2;, I cannot use this code. Is there any other way to achieve this? I want to be able to use this method on any T (class, struct, primitive)  This question is not a duplicate of . As I wrote in the comment, I do not have to use ==. It is just one of the ways I have tried


Bluetooth and speaker occasionally working on ASUS N550JV

I use a ASUS N550JV laptop with Ubuntu 14.04 and Windows 8 dual boot. The Bluetooth module is atheros ar3012. Since the day Ubuntu is installed, the behavior of Bluetooth and speaker is weird. They are not totally dead. They sometimes work, but I find no pattern about when they  work and when they don't. Sometimes Bluetooth works right after start up. In other time, the Bluetooth icon does not show up in menu bar (I have "Show Bluetooth status shown in menu bar" checked in settings). When I enter settings, Bluetooth is shown to be off. Even though I can set it to On by clicking it, the device menu below still shows "Bluetooth is disabled" and I cannot search and add device (I use a Bluetooth mouse). Also, if I close the settings and open it again, Bluetooth will be set to off again. The same is with the speaker. Sometimes it works right after startup but sometimes it just refuse to work. I am so confused. Could anyone  tell me how to solve this problem? Thanks in advance.  P.S. Every time I start up, at the page where I enter my password to log in, it always pops up a window titled "Authentication required by Wi-Fi network" and asks me for wifi password. But even if I type in the password, the connect button is still grayed out. Does this has anything to do with the problems above?  Edit: I checked /var/log/dmesg and the error about bluetooth is as follow:     [    5.032070] Bluetooth: Error in firmware loading err = -110,len = 448, size = 1184   [    5.032126] Bluetooth: Loading sysconfig file failed   [    5.032166] ath3k: probe of 3-5:1.0 failed with error -110


Dict output coming all disordered when converting a list of tuples to dict

I'm working with database query results. The output would be like this:  rows = [(1, 2, 3), (4, 5, 6), (7, 8, 9)]  Which would be, say, 3 rows of table data from the db  And the column names are like this:  cols = ['col1', 'col2', 'col3']  I want make a list of dictionaries out of them, like this:  {'col1':1,'col2':2,'col3':3} {'col1':4,'col2':5,'col3':6}   So I did this:  res=[] for row in rows:   res.append(dict(zip(cols,row)))   But res is like this:  [{'col2': 2, 'col3': 3, 'col1': 1}, {'col2': 5, 'col3': 6, 'col1': 4}, {'col2': 8, 'col3': 9, 'col1': 7}, {'col2': 2, 'col3': 3, 'col1': 1}, {'col2': 5, 'col3': 6, 'col1': 4}, {'col2': 8, 'col3': 9, 'col1': 7}]   I can't figure out why the key-value pairs aren't in order by column names. It's not a huge problem, I can sort the dict elements by key names, but how do I get them in order in the first place, without the need to sort them?


Tags are not showing up on the right side of the screen

This is on Stack Overflow. On Meta I'm able to see what the tags are on the right side of the screen. In fact, I think yesterday or some point earlier today I saw tags on the right side of the screen (I can't screenshot or remember correctly).  It's right above the asked and active heading.  I know this is minor but what happened to it? It might be useful for browsing instead of having to look at the bottom of the question post.    Found an image on Google and it shows the tags on the right side of the screen:


If we can see only visual light then why we can't see other electromagnetic radiation as they also a type of light?

Why we can't see other than visual light??


Properties of $y$ if $\frac{d^2y}{dx^2}+xy=0$, $x \in [a,b],$ and $y(a)=y(b)=0.$

Let $y$ be a nontrivial solution of the boundary value problem  $$\frac{d^2y}{dx^2}+xy=0,\ x \in [a,b]$$  $$y(a)=y(b)=0$$ Then:   $b>0$ $y$ is monotone in $(a,0)$ if $a<0<b$. $y'(a)=0$. $y$ has infinitely many zeros in $[a,b]$   I have no idea how to solve it and which options is/ are correct. please help me.


Why are the dineutron and diproton unbound?

It is known that there are no diproton or dineutron nuclei.  Does this mean that two protons or neutrons are not actually attracted to each other? Even if the attraction was weak, wouldn't it cause bound states anyway?  Related:


I'm working through Massey's "Basic Course in AT."  One of the problems is prove that a homeomorphism of the closed disk maps the boundary to the boundary and the interior to the interior.  How would one prove this?  I can't seem to get this one problem.


Ubuntu 16.04 - Where is the "make link" command now?

I upgraded from Ubuntu 14.04 to 16.04 (which appears to be the latest). There have been a number of changes that are annoying but the current worst is my inability to "make link". I have Files 3.18.5 and there no longer is a "make link" when I right click on a Folder or a File. Help...


Taking someone else's cancelled German visa appointment slot - realistic?

A friend of mine has a visa appointment at German embassy booked at 14th of June. Mine is 20th of June, as there were no earlier dates available. Now, my friend wants to cancel her appointment.    Does anyone know how soon the time she cancelled appears as available if I want to re-schedule mine?    I am aware that it takes 1-2 days to delete my information from embassy's database, which means I have to wait to be able to book an appointment. I can cancel my appointment first, then ask my friend cancel hers. I am afraid I might miss her date, so I need to know whether it appears immediately after she cancels or there is another procedure as well.


im using zalenium for a remote driver but when i invoke the url the browser open and then trows a java null pointer exception  y tried to change the capabilities   public void GetInvoicing() throws MalformedURLException {    System.out.println("launching chrome browser");     DesiredCapabilities capability = DesiredCapabilities.chrome();    ChromeOptions options = new ChromeOptions();     //options.addArguments("headless");     options.merge(capability);    RemoteWebDriver driver = new RemoteWebDriver (new URL("https://zalenium.payclip.com/wd/hub"),capability);    driver.get(baseUrl); }    @Test(priority=1)   public void Test1() throws Exception {   GetInvoicing();   driver.findElement(By.name("username")).sendKeys("santiago.galicia"); driver.close();     }   the error that i get is the next  FAILED: Test1 java.lang.NullPointerException     at InvoicingDashboard.TestCases.Test1(TestCases.java:77)     at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.base/java.lang.reflect.Method.invoke(Method.java:566)     at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)     at org.testng.internal.Invoker.invokeMethod(Invoker.java:580)     at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:716)     at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:988)     at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)     at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)     at org.testng.TestRunner.privateRun(TestRunner.java:648)     at org.testng.TestRunner.run(TestRunner.java:505)     at org.testng.SuiteRunner.runTest(SuiteRunner.java:455)     at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:450)     at org.testng.SuiteRunner.privateRun(SuiteRunner.java:415)     at org.testng.SuiteRunner.run(SuiteRunner.java:364)     at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)     at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:84)     at org.testng.TestNG.runSuitesSequentially(TestNG.java:1208)     at org.testng.TestNG.runSuitesLocally(TestNG.java:1137)     at org.testng.TestNG.runSuites(TestNG.java:1049)     at org.testng.TestNG.run(TestNG.java:1017)     at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:114)     at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)     at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)  ===============================================     Default test      Tests run: 1, Failures: 1, Skips: 0


If $x,y,z>0$ are distinct and $x+y+z=1$ what is the minimum of $\left((1+x)(1+y)(1+z)\right)/\left((1-x)(1-y)(1-z)\right)$?

If $x,y,z>0$ are not equal and positive and if $x+y+z=1$ the expression   $$\frac{(1+x)(1+y)(1+z)}{(1-x)(1-y)(1-z)}$$  is greater than what quantity?


Trying to turn on my kids' iPad which has been off for a few months.  Tried several of my 'usual' passcodes, but iPad became 'disabled' before I could try them all.  Now it's "iPad is disabled, connect to iTunes"  Connecting to iTunes via hold-home-and-plug-in-USB pops up iTunes with "Restore" or "Update".  Do NOT want to lose all data, there are probably photos on there that are not backed up.  Is there ANYTHING I can do?  I'm not even sure which version of iOS is on there, but it's 8.something...  If I could just get a few more attempts to enter PIN, I would figure it out eventually.  Can I jailbreak it in this condition? Somehow pull the data before Restoring/Updating?  HELP!


I started a process from the command line, but the window server died. However I see the process I started is still running. Is it possible to connect a terminal to the process to see its output?  This is the process:  ps -A | grep foo 73186 ??       4011:34.91 ./foo


I am preparing for an exam and one of the previous examples deals with LDA: The question is to prove that the total-scatter matrix in Multi-Class LDA can be expressed as the sum of the between-scatter matrix and the within-class scatter matrix.  See the whole question here:    I have found some help online to work through the problem but I am stuck now - I found this slide in a course presentation online (full presentation here www.cse.msu.edu/~cse802/DHSCh3_Component%20AnalysisDiscriminants2012.pptx):      I am able to follow this until it comes to the split - how is (x-mi+mi-m)^2 the same as (x-mi)^2 + (mi-m)^2?  I feel like I am missing something obvious here ...   I also found this topic here but it didn't seem to go anywhere:   Thanks in advance for any help/advice you can offer.


Getting error from apt-get when trying to install php5 package

I am new in ubuntu and I try to run a website by my own computer but I can't install php5. When i typed:  sudo apt-get install php5   I received:     Package php5 is not available, but is referred to by another package.   This may mean that the package is missing, has been obsoleted, or is   only available from another source      E: Package 'php5' has no installation candidate   What does it mean?


is it possible to install a linux distro in an unmounted partition without a bootable device

Maybe the question is stupid, but I haven't been able to find anything anywhere to confirm that.  I have 1TB HDD which has two ext4 partitions. In one partition, I've my main OS (Ubuntu). And another partition is empty.  I'd like to install an another OS in my second partition. Is it possible, while being in one partition (Ubuntu), to install an OS in another unmounted partition ( and finally update the grub menu ).  Thank you.


Best approach for dealing with time measures?

My goal is to write a framework for measuring method execution or transaction time and for processing the measurements, i.e. storing, analysis etc. Transaction may include calls to external systems, with synchronously or asynchronously waiting for the results.  There already have been some questions around that topic, like    ""  ""  ""   And all the answers boil down to three approaches for taking the time   System.currentTimeMillis() System.nanoTime() Instant.now() and Duration(since Java 8)   I know, all of these have some implications  System.currentTimeMillis()  The result of this method depends on the platform. On Linux you get 1ms resolution, of Windows you get 10ms (single core) ~15ms (multi core). So it's ok for measuring large running operations or multiple executions of short running ops.  System.nanoTime()  You get a high resolution time measure, with nano second precision (but not necessarily nano second accuracy) and you get an overflow after 292 years (I could live with that).  Instant.now() and Duration  Since Java 8 there is the new time API. An instant has a second and a nano second field, so it uses on top of the Object reference two long values (same for Duration). You also get nano second precision, depending on the underlying clock (see ""). The instantiaion is done by invoking Instant.now() which maps down to System.currentTimeMillis() for the normal System clock.  Given the facts, it becomes apparent, that best precision is only achievable with System.nanoTime(), but my question targets more towards a best-practice for dealing with the measures in general, which not only includes the measure taking but also the measure handling.   Instant and Duration provide best API support (calculating, comparing, etc) but have os-dependend precision in standard case, and more overhead for memory and creating a measure (Object construction, deeper callstack) System.nanoTime() and System.currentTimeMillis() have different levels of precision but only have basic "api" support (math operations on long), but are faster to get and smaller to keep in memory.   So what would be the best approach? Are there any implications I didn't think of? Are there any alternatives?


What happens to my checked-in luggage if I skip the final leg of a multi-stop flight?

Looking for a flight from Chicago to Scotland in the summer, and the cheapest by far is to fly Toronto-Edinburgh. Outbound flight is direct while return flight connects through Chicago. I want to get off in Chicago. (This flight + one way Chicago to Toronto is still several hundred cheaper than Chicago-Edinburgh round trip)  Wouldn't I have to pick up my baggage after customs inspection upon return to the US at O'Hare before boarding the connection to Toronto, so I could just leave the airport at that point? It's the last leg of my trip so having a leg canceled wouldn't be an issue.  To add detail as to why this question is different than others -- I am specifically asking about baggage policy, since bags will be checked in this case. I recall a past flight back into the US with a domestic connection and I had to pick up my bags then drop them off with a connection agent to route to my final destination. Is this still policy? The caveat is that I am talking about a flight covering three countries total (Scotland -- US -- Canada) but wish to bypass the US to Canada leg.


How can I derive the ? I don't want to use hyperbolic functions and the fact that the light waves travel by forming spherical wavefronts. Is there a way to derive the Lorentz transformations applying the conditions I have mentioned. I was unable to understand the method given in Landau and lifshitz deeply. That's why I want a method other than the one using hyperbolic functions


How to find the solution of a quadratic equation with complex coefficients?

I know how to find the solution for a quadratic equation with real coefficients. But if the coefficient changes to complex numbers then what is the change in the solution? Want an example of such equation with solution.


Using \section*{} messes up equation numbering?

Here is my code:   \documentclass[letterpaper,10pt,fleqn]{article}  \setlength{\mathindent}{1cm}     \usepackage{geometry} \geometry{textheight=9in, textwidth=6.5in} \usepackage{amssymb}                                          \usepackage{amsmath}                                           \numberwithin{equation}{section}  \parindent = 0.0in \parskip = 0.2in  \begin{document}  \section*{New Section} \hrule  Text      \begin{align}  \phi =& \int_S \mathrm{d}a\\       =& \int_S f(u, v) |\mathbf{T}_u \times \mathbf{T}_v| \mathrm{d}u\mathrm{d}v \end{align}  \end{document}   I don't want the number to be in front of "New Section", so I am using the asterisk \section*{New Section} but I do want the equations to be numbered as (1.1) and (1.2) etc.  However, I have found that using the asterisk sets the equation numbers to (0.1) and (0.2) and I have yet to find a way around this.


$V$ be a vector space , $T:V \to V$ be a linear operator , then is $(\ker(T) \cap R(T) ) \times R(T^2) \cong R(T)$?

Let $V$ be a vector space , $T:V \to V$ be a linear operator , then is it true that  $(\ker(T) \cap R(T) ) \times R(T^2) \cong R(T)$ ?  (note that the direct product is well-defined as both the spaces are subspaces of $V$ so have same ground field )   See     , note that the isomorphism holds when $V$ is finite dimensional as it is known that if $U,W$ are finite dimensional vector spaces over  a same field , then $\dim (U \times W)=\dim U + \dim W$ . Also note that the example given in the linked question doesn't violate the stated isomorphism here . Please help . Thanks in advance .  EDIT : One general thing that can be noted is that $R(T)/R(T)\cap \ker (T) \cong R(T^2)$ holds , but I don't know whether it can be used to prove or disprove the claim in question   NOTE : If $V,W$ are vector spaces over a field $F$ then $V \times W$ is a vector space with  addition and  multiplication defined as $(v,w)+(v',w'):=(v+v',w+w') $ ; $ k.(v,w):=(kv,kw)$ . It can be seen that if $B_V , B_W$ are bases for $V , W$ repectively , then $(B_V \times \{O_W\})\cup (\{O_V\}\times B_W)$ is a basis for $V \times W$ , so that if $V,W$ are finite dimensional then so is $V \times W$ and   $\dim (V \times W)=|(B_V \times \{O_W\}) \cup (\{O_V\}\times B_W)|=|B_V \times \{O_W\}|+|\{O_V\}\times B_W|=|B_V|+|B_W|=\dim V + \dim W$   So this "direct product" is substantially different from "direct sum"


Does matter simply releases energy in wood burning fire or does some matter actually convert into energy?  Blue flame considered as complete combustion but in ceramic plates gas heaters for room warming, we see/prefer red colour plates?


Show that $L^{\infty}$ space does not have a countable dense set.

I was able to show that when $p ≥ 1$, the $L^p$ space on the interval $[0,1]$ has a countable dense set.  However, when $p$ is infinite, how to prove that $L^p$ space on the interval $[0,1]$ does not have a countable dense set? I can't find some way to approach.


How should a family with young children apply for UK visas?

We are sponsoring a family to visit us in UK as friends from Madagascar for two weeks. They have a 6 year old and a 16 month old.   Do the kids need their own visas, and are they the standard visitor visa or a special child visa?   Also, when I try and apply on the website I can only apply for one person so how do I apply for all the individuals in the family?   I have looked on the Immigration website and can't find the answers I need.


order of non abelian group can't be what?

Let $G$ be a non abelian group; then its order can be:   $25$ $55$ $35$ $125$   I think the order cannot be $25$ and $35$. But from option $55$ and $125$ which one is not possible?   Why not $25$ because every group of order $p^2$ is abelian. Here $p$ is $5$. Why not $35$ because $35=5*7$ and $5$ does not divide $7-1$. There there is only one group which is cyclic up to isomorphism of order $35$.


Rolling two fair dices $A$ and $B$ and counting the number of odds where $B$ is rolled once more than $A$

Suppose $A$ and $B$ each roll a fair six sided dice $101$, $100$ times respectively. If we count the number of odds and evens in each sequence, what is the probability that $A$ has more number of odds than $B$ does? I think the probability is $1/2$ if we roll both $A$ and $B$ the same number of times. But how does the probability change if we roll $A$ one more time?


Numbering a coloured box outside of the box

I want numbered the third (blue) equation in out of box. what do I do?


cd / && du -sh . told me that the filesystem used 2.1G spaces of disk:  root@ubuntu:/# cd / &&  du -sh . du: cannot access './proc/3874/task/3874/fd/3': No such file or directory du: cannot access './proc/3874/task/3874/fdinfo/3': No such file or directory du: cannot access './proc/3874/fd/4': No such file or directory du: cannot access './proc/3874/fdinfo/4': No such file or directory 2.1G    .   However, df -h told me that all spaces had been used:  root@ubuntu:/# df -h Filesystem      Size  Used Avail Use% Mounted on /dev/root       7.2G  6.8G     0 100% / devtmpfs        3.6G     0  3.6G   0% /dev tmpfs           3.9G     0  3.9G   0% /dev/shm tmpfs           3.9G   17M  3.9G   1% /run tmpfs           5.0M     0  5.0M   0% /run/lock tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup   Here is the output of fdisk -l:  Disk /dev/mmcblk1: 7.4 GiB, 7948206080 bytes, 15523840 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x00000000  Device         Boot Start      End  Sectors  Size Id Type /dev/mmcblk1p1       2048 15523839 15521792  7.4G 83 Linux   I don't why I have 6.8G spaces used, also, I don't know why df -h showed me the /dev/root instead of /dev/mmcblk1p1. ls /dev/root even showed me No such file or directory error.


Bug rendering spoilers with tags in them

As can be seen in , it seems that spoiler and tag markdowns don't play well together - the tag markdown within a spoiler markdown is clearly visible:


How to buffer balanced (XLR) audio signal while forwarding phantom power

Background: I have a condenser microphone, which requires +48V phantom power from my mixing desk. The microphone has a source impedance of "<200 Ohm" as per manufacturer. As you may recall, phantom power is delivered over both the "+" and "-" wires in the XLR connector, put on the wire with a 6.8 kOhm resistor pull-up on each wire. This means the maximum amount of current that can be drawn is about 14 mA (into a short) and more realistically < 10 mA. Some of this power is used by the built-in pre-amp in the microphone data sheet says 2.5 mA. I've built an inline mute switch using a DPDT switch (rated for +48V DC) where the "mute state" switches the phantom power over to a blinking LED, reminding me I'm on mute. Unfortunately, because this is a mechanical switch, AND because of the phantom power, switching on/off makes for loud pops. Given that I want the blinky-LED to consume some current when in the "mute" configuration, I probably need to switch off the pre-amp in the microphone to have enough current available -- and, anyway, I do need to turn off the signal from the microphone for it to be "muted." With that background, I believe that I need to build some kind of active/solid state circuitry to mute/un-mute the microphone, turn on a blinking LED when it's muted, and still pass phantom power to the microphone. It's the last part that has me somewhat confused. Because the original source of the phantom power is already resistively protected with high impedance, how do I best re-buffer the signal, yet carry the phantom power forward without too much power loss? I've considered extracting the common mode power with a center-tap transformer, and then using my own opamp to re-buffer the signal (which I can then turn off when needed) but this feels quite inelegant as I add another couple of high-resistance resistors in the path of the power. Yet, I don't know how to pass the power without also passing the signal any other way. Here's an example sketch of what I have so far:  Microphone on the left, mixing desk on the right. I'm looking for suggestions on how to better accomplish the separation of signal vs phantom power, ideally in a way that doesn't require adding more inline high-resistance resistors.


Can anyone identify the LaTeX font in this expression?

I have a document which includes the following expression:   Can anyone identify the font or symbols used for the D and T characters at all?   I don't have the source LaTeX and need to reproduce this expression exactly.


I start my master studies this fall in quantitative finance/economics in Europe. Since this will just take 3-4 semesters I want to take a look ahead and obviously PhD is one option to do.   So I am wondering if it makes sense to go to the US for PhD, since I will have already a master's degree in two years. I read a lot about the US PhD's which can be started after bachelor and therefore are somehow like a European master & PhD combined.   I saw some PhD programmes from well-known US universities and their curriculum contained almost just courses I will already have in my master. Wouldn't that be a waste of time to repeat them? Specially compared to my country (Switzerland) where a PhD duration is between 3-4 years.  Every input/personal experience will be appreciated.


Comma before "include:" preceding list: right or wrong, and why?

My first style disagreement with another writer at a new job. I say the comma in the example below is superfluous because there is no introductory or non-restrictive clause. I think the options are: "Key takeaways from the press release include:" or "There are many key takeaways from the press release, including:" Context: This was included in an email to our marketing team announcing the distribution of a press release, so if any of us get questions we'll all have the same answer. As written:  Key takeaways from the press release, include: This thing digitizes stuff and simplifies workflows. This thing changes how we see stuff, and makes customers happy. This thing improves the integrity of our stuff. This thing helps people see how stuff is being used.


A customer purchases clothes  worth 200 Rupees from a shop. customer gives 1000 Rupee note. Since shop owner does not have change, he collects change (100 * 10 notes) from the neighbor shop and gives 800 rupees back to the customer.  After few hours neighbor shop keeper tells the shop owner that 1000 rupee note is fake and collects his 1000 rupees.  So now calculate the total loss to the shop owner.  Assume that Shop owner is selling clothes without any profit.


Need to get Flash running on Firefox 49.0 using 14.04

I currently have libflashplayer.so in the mozilla plugin folder, but still flash is not working with Firefox 49.0 under Ubuntu 14.04?  Any assistance would be greatly appreciated.  Been at this for a look time.  Thanks


The attribute image.itemtype has an invalid value

I am using JSON-LD format for Structured data. In home page @type=website & in details page @type=Article. Logo property of Organization section in details page showing following warning in Google Structured Data Testing Tool But home page is not although in both page value is same.      (The attribute logo.itemtype has an invalid value.)   Home page JSON-LD  <script type="application/ld+json">     {     "@context": "http://schema.org",     "@type": "WebSite",     "url": "http://kothaboli.com/",     "name": ".....",     "alternateName" : "....",     "description" : "......",     "potentialAction": {         "@type": "SearchAction",         "target": "http://kothaboli.com/search?keywords={search_term_string}",         "query-input": "required name=search_term_string"     },     "sameAs":[         "https://www.facebook.com/kothaboliDotCom/",         "https://twitter.com/kotha_boli",         "https://plus.google.com/+kothaboli"     ],     "publisher" : {         "@type" : "Organization",         "name" : "....",         "alternateName": "...",         "logo": "http://kothaboli.com/media/1018/ka.jpg"         }     } </script>     Details page JSON-LD      <script type="application/ld+json">     {     "@context" : "http://schema.org",     "@type" : "Article",     "url": "http://kothaboli.com/interviews/intellectual/arundhati-roy/",     "name" : "... ....",     "headline":  "...--’",     "datePublished" : "7/26/2016 1:10:05 AM",     "dateModified" : "8/12/2016 1:50:54 AM",     "image" : "http://kothaboli.com/media/1088/33333333.jpg",     "articleSection" : "....",     "articleBody" : ".....’ ",     "mainEntityOfPage": "..",     "author" : {         "@type" : "Person",         "name" : "....",         "alternateName": "Arundhati Roy"         },     "publisher" : {         "@type" : "Organization",         "name" : "...",         "alternateName": "Kothaboli",         "logo": "http://kothaboli.com/media/1018/ka.jpg"         }     } </script>


How to link controllers in Ruby On Rails?

Sometimes I need from one controller to use operations from another controller. What I do now is instantiate it and use its operation, but it gives me the feeling that it is not correct what I do, so I have been taught that there can not be several instances of the same controller.  What is the best practice? Thank you very much.


What started the magnetic field of Earth

The  gives a good explanation of the magnetic field of the Earth: the Coriolis force focus inner currents into current spirals generating magnetic(s) field(s).  What I'm trying to understand is the origin of these inner currents.  For currents to appear, there should exist charges moving. If such important charges exist, there is one or many mechanisms at work to separate positive and negative ions. Of course among these mechanisms a magnetic field acting on currents is a pretty good explanation (see : a magnetic field on a rotating conducting fluid is able to create currents and these currents in turn will create a magnetic field). But at the same time this loop between cause and effect isn't completely satisfying and should have been started in an external way.  What might have started an unbalance in positive and negative ions inside Earth to bootstrap inner currents and then its magnetic field?  What process might explain the starting of the magnetic field of the Earth without the hypothesis this magnetic field was already there?


Sum of infinite series $1+\frac22+\frac3{2^2}+\frac4{2^3}+\cdots$

How do I find the sum of $\displaystyle 1+{2\over2} + {3\over2^2} + {4\over2^3} +\cdots$   I know the sum is $\sum_{n=0}^\infty (\frac{n+1}{2^n})$   and the common ratio is $(n+2)\over2(n+1)$ but i dont know how to continue from here


Is there a way to stop Windows 8.1 from trapping my mouse cursor when moving between screens?

I just upgraded to Windows 8.1, and immediately I notice that unless I deliberately wind up and "slam" my mouse cursor against the edges of my screens, it gets stuck on the last pixel before crossing. I'm guessing this was in response to people who had a hard time using the charms with a mouse in Windows 8.0. Dealing with Windows 8.0's single-pixel traps in the corners was annoying enough! I don't want to have a chug a five-hour energy every day just to use a multimonitor workstation.     Things like this seem to commonly have a setting somewhere, be it in the control panel, the registry, some group policy thing, or elsewhere. I'm at a loss so far. How can I stop windows from grabbing my cursor?


Install proprietary drivers 14.04 NVIDIA (steam segmentation issue)

Recently, I finally got the official drivers for my NVIDIA 560 Ti card installed on Ubuntu 14.04 (hooray) However I started looking into installing Steam and I'm getting segmentation errors when I try to run the software. I tried installing 32-bit libs and it seemed like they weren't available or they were already installed. Upon further investigation, I found that a solution is to install the proprietary drivers, install steam then switch back to the other drivers. I'm not really sure what "proprietary drivers" are in all honesty. Has anyone gone through this process that could provide some insight here?  (I installed the official 64-bit driver from the NVIDIA site for my 560 Ti just for reference. And the Ubuntu version installed is 64-bit as well)  Update:  This is the error text I get when trying to run steam after installing it via the ubuntu store.  Running Steam on ubuntu 14.04 64-bit STEAM_RUNTIME is enabled automatically Installing breakpad exception handler for appid(steam)/version(1401381906_client) /home/dbrewer/.steam/steam.sh: line 755:  3943 Segmentation fault      (core dumped) $STEAM_DEBUGGER "$STEAMROOT/$PLATFORM/$STEAMEXE" "$@" mv: cannot stat ‘/home/dbrewer/.steam/registry.vdf’: No such file or directory Installing bootstrap /home/dbrewer/.steam/bootstrap.tar.xz Reset complete! Restarting Steam by request... Running Steam on ubuntu 14.04 64-bit STEAM_RUNTIME has been set by the user to: /home/dbrewer/.steam/ubuntu12_32/steam-runtime Installing breakpad exception handler for appid(steam)/version(1401381906_client) /home/dbrewer/.steam/steam.sh: line 755:  4066 Segmentation fault      (core dumped) $STEAM_DEBUGGER "$STEAMROOT/$PLATFORM/$STEAMEXE" "$@"   What I get when I run "steam --reset"  mv: cannot stat ‘/home/dbrewer/.steam/registry.vdf’: No such file or directory Installing bootstrap /home/dbrewer/.steam/bootstrap.tar.xz Reset complete!


What is the difference between primary coverage and secondary coverage on a travel insurance policy? Which is recommended for short-term travelers?


I have to give the Taylor series of $\sqrt{1+x}$ with development point $0$. But I am not quite sure what to do.  Normally you have to give the Taylor series up to a certain order.  Well $T_f(x,0)=\sum_{n=0}^\infty \frac{f^{(n)}(0)}{n!}x^n$  I calculated the derivative of $f(x)=\sqrt{1+x}$ up to order 5 and locked for a regularity.   $f^{(n)}(0)=(-1)^n\cdot\frac{\prod_{k\leq n\,\text{with}\, k\,\text{odd}}k}{2^{n}}$  Then the Taylor series is given by:  $T_{f}(x,0)=\sum_{n=0}^\infty \frac{(-1)^n}{\prod_{1\leq k\leq n\,\text{with}\, k\,\text{even}}k\cdot 2^n}x^n$  Which is pretty ugly to work with.  Can you confirm this solution?  Thanks in advance.


Restrictions on universal generalization

doesn't seem to give a satisfactory explanation of the restrictions on when it can be used:  Assume $\Gamma$ is a set of formulas, $\varphi$ a formula, and $\Gamma \vdash \varphi(y)$ has been derived.  The generalization rule states that $\Gamma \vdash \forall x \varphi(x)$ can be derived if $y$ is not mentioned in $\Gamma$ and $x$ does not occur in $\varphi$.  The article then gives an example of UG being used incorrectly to derive $\exists z\exists w(z\neq w) \vdash \forall x(x\neq x)$, with the restrictions given certainly being violated.  However, wouldn't the following modification of the "proof" be in accordance with the restrictions?  $\exists z\exists w(z\neq w)$ $\exists w(y\neq w)$ $y\neq x$ $\forall\alpha(\alpha\neq x)$ $x\neq x$  Here, the generalization in step 4 has been amended to use $\alpha$ as the quantifier's bound variable, which should be permitted, as $\alpha$ does not occur in $y\neq x$ and $y$ does not occur in the assumption $\exists z\exists w(z\neq w)$, yet this leads to a universal instantiation that is clearly false!  Is the $\Gamma$ of the restrictions meant to be all previous steps of the proof, not just the assumptions?  If so, wouldn't this invalidate the proof given further in the article that includes the steps $P(y)\to Q(y)$ and $P(y)$ before generalizing $Q(y)$?  Does the presence of existential instantiation place further restrictions on universal generalization somehow, with the existential instantiated counting as a mention of the variable introduced?


Making multiple attacks with attack bonus

I'm not quite sure how the total attack bonus interacts with BAB.   Can you make more attacks than shown by your BAB (e.g. +11/+6/+1 BAB allows you to make 3 attacks) by having a high enough DEX, STR or other attack bonus modifiers? Assuming I have +11/+6/+1 BAB, and a spell gives me +6 attack bonus, would that make me able to attack as if I had +17/+12/+7/+2 BAB, giving me an extra attack?)   Can you make multiple attacks even if you have one of your stats drained, making your attack bonus negative, or less than 5?      It says in the SRD that the formula for attack bonus in melee is this:       Base attack bonus + Strength modifier + size modifier   I've also been told that you can make multiple attacks in one turn, but each attack gains a -5 penalty to attack bonus.


Given enumitem + beamer incompatibility, How do I adjust the indent of the enumerate environment?

Given the enumitem + beamer incompatibility discussed in detail , How do I adjust the indent and vertical separation of the items in an enumerate environment?  As alluded to in a relevant post, an application might be to fit the enumeration more snugly into a tabular environment (via minipage).


Firefox update fails; "Could not get lock" error when I run sudo apt upgrade

I am new to Ubuntu. I have installed Ubuntu MATE in my p.c. Now when I opened browser Mozilla Firefox it searched for a update. So I have been updating it but it fails every time.  sudo apt update works well.  sudo apt upgrade throws this error:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   How can I update all the applications in Ubuntu MATE as well as Mozilla Firefox?


Let p be an odd prime number, and let n be a positive integer divisible by p. Show that $D_n$ has only one p-Sylow subgroup  I'm trying to prove this by saying np($D_n$) = ap+1 and a must be 0, but I'm stuck at the process of proving a have to be 0. How can I achieve it, thank you very much! (np(group G) means the number of p-Sylow subgroup in the group G)          It's solved, thanks to Arturo Magidin!


Regex that can only contain alphanumeric characters and underscores, but the first character must be alphabetical (single character failure)

I have the following regex pattern:  ^[A-Za-z][A-Za-z0-9_-]+$`    It is used to match; alphanumeric characters, underscores and dashes, with the first character being alphabetical.  This works as expected, but I also need it to be able to match single characters. A conditions of a fails.  How can I modify the pattern to make a single alphabetical character pass?


Writing a very simple guessing game in Java

I'm new to programming and while working on the Head First Java book I wanted to make a simple program, but there are some points I can't do. What I want the program to do is keep an integer number between 0 and 100 randomly and the user tries to find it. If the user finds the number, congratulations will appear on the screen. If not, it will ask for a new prediction. The code I wrote is below: package Intro; import java.util.Scanner;  public class GuessingGame {     public static void main(String[] args) {          Scanner input = new Scanner(System.in);          System.out.println("Please enter a number: ");          int prediction = input.nextInt();          int number = (int) (Math.random());          if (number==prediction) {              System.out.println("Congratulations!");         }           else {              System.out.println("Wrong answer! Try a new number: ");          }            } }  The point I stuck is that I can't make the randomly stored number integer and a number between 0 and 100. Another point is that if the answer is wrong, the program does not want a new prediction.


Very low quality flag declined, and still question was closed as off-topic

My very low quality flag to  (10k only now) was declined with the following reason     declined - a moderator reviewed your flag, but found no evidence to support it.   However, the question was later closed as off-topic which makes me wonder what is the difference between the two?


What are reserved filenames for various platforms?

I'm not asking about general syntactic rules for file names. I mean gotchas that jump out of nowhere and bite you. For example, trying to name a file "COM<n>" on Windows?


I need something like this:  \left\{ first line  (1a) second line (1b) third line  (1c) \right.   all lines should be aligned to left


I have a 1 column df with 37365 rows. I would need to separate it in chunks like the below: df[0:2499] df[2500:4999] df[5000:7499] ... df[32500:34999] df[35000:37364]  The idea would be to use this in a loop like the below (process_operation does not work for dfs larger than 2500 rows) while chunk <len(df):     process_operation(df[lower:upper])  EDIT: I will be having different dataframes as inputs. Some of them will be smaller than 2500. What would be the best approach to also capture these? Ej: df[0:1234] because 1234<2500


Should I use repeated measures ANOVA or one-way ANOVA?

I am conducting a study on different image reconstruction algorithms for computed tomography (CT). My aim is to investigate which of the image reconstruction algorithms that have the highest signal-to-noise ratio (SNR). My dataset is 100 patients who underwent a CT brain scan. Each CT scan will be reconstructed with 4 different image reconstruction algorithms. Then I will measure the SNR for each algorithm and patient and compare the different reconstruction algorithms with regard to the SNR. So, we scan the patient's head and then the computer at once provides four different image reconstruction algorithms of the scan (4 different image sets) and then we measure the SNR of each image set and compare it to the other reconstruction algorithms (other image sets). Or, if it makes it easier for you to think. Consider the following corresponding scenario: You take a blood sample (corresponding to "CT scan") from the patient and measure the glucose level with 4 different apparatus (corresponding to the 4 different image reconstruction algorithms). And then you compare the blood glucose level (corresponding to "the SNR") between the four different apparatus. So, my question is if I should use a repeated measures ANOVA or just an ordinary one-way ANOVA.


Is it safe to use RAM sticks with different frequencies?

I have two RAM sticks: one 533 MHz and one 667 MHz. Is it safe to use both of these in the same system?


login/non-login and interactive/non-interactive shells

Are the concepts of login/non-login shells the same as the concepts of non-interactive/interactive shells (respectively)?  Or are the concepts orthogonal yielding four different combinations?  I am trying to get a clear picture of which .bashrc, .bash_profile scripts get sourced under various circumstances and I find that articles sometimes use these concepts interchangeably.


A space $Y$ is Hausdorff iff the diagonal $D = \{(y_1,y_2)\in Y\times Y: y_1=y_2\}$ is closed

Show that the topological space $Y$ is Hausdorff iff the diagonal $D = \{(y_1,y_2)\in Y\times Y: y_1=y_2\}$ is a closed subset of $Y\times Y$.   My attempt: First, suppose $Y$ is Hausdorff. Then $Y\times Y$ is Hausdorff, so for any $y\in Y\times Y - D$ and $y'\in D$, I can find open sets $U_y$ and $U_y'$ such that $U_y\cap U_y' = \varnothing$. This means that $y\in U_y\subseteq Y\times Y -D$, so $Y\times Y -D$ is open, which implies that $D$ is closed.  Does anyone see anything wrong with my argument?  For the converse, I'm a little stuck. My hunch is that since $D$ is closed, $Y\times Y-D$ is open, and I want to use this somehow to show that $Y\times Y$ is Hausdorff. Then we can conclude that $Y$ is Hausdorff. Any advice?


I'm aware that if I press esc followed by typing :q!, I can exit the vim editor, due to .  However, the standard convention is for programs to exit when ctrl + c is pressed, which sends a SIGINT to the currently running process.  For example, top, tail -f, and ping all follow this convention.  My question is this: Why doesn't vim follow this well-established convention? Is there a historical reason, or is it something else?  It seems to me that it would avoid a lot of confusion for new users if it followed this standard convention like everything else.  (While we're at it, why is it SIGINT and not SIGTERM in the first place?)


What is the logic behind uncountable nouns?

I'd like to understand the logic behind uncountable nouns, such as "water", "meat" and others, specially "bread", for example.  I don't understand why can't we count them, since there are different kinds of water (e.g.: still, tap, sparkling, etc.), meat (e.g: beef, pork, etc.) and bread (baguette, bun, etc.).  Sorry if my question seems silly, but I'm not a native speaker.


Why does the toString method in java not seem to work for an array

I want to convert a character array to a string object using the toString() method in java. Here is a snippet of the test code I used:  import java.util.Arrays; class toString{     public static void main(String[] args){         char[] Array = {'a', 'b', 'c', 'd', 'e', 'f'};         System.out.println(Array.toString());         } }   In principle, it should print abcdef, but it is printing random gibberish of the likes of [C@6e1408 or [C@e53108 each time the program executes. I don't need an alternative out of this but want to know why this is happening.


Changing max/min a function will be plotted with pgfplot

I was hoping someone could shed some light on this issue: When I plot a function using something like \addplot+[mark=none,smooth,] (\x,{2 * \x^2 + 4 * \x + 1}); the line of the function does not extend far enough in the window. In other words, how can I expand the domain of the function being plotted?  An example of the plot I am currently creating:


Recursively traversing a tree in a collection in Python

I have 100 collections and they form a complex tree structure. I would like to enable the Holdout and Indirect Only options for the 50 specified collections from the entire collection. In order to properly handle the tree of collections, I can predict the maximum depth and write for loops in layers, but I found a hint that the recursive function is excellent at solving this type of problem. However, recursion was difficult for me, so I failed to write my own code. How can I write a recursion that digs through a collection of tree structures to the end and then returns back?


Why will Blender render the transparent area with shadow catcher on?

One thing that puzzled me a lot is when I add shadow catcher to the ground floor, and render it, Blender will treat that transparent area as opaque one and render it as well, this causes extra render time waste, especially in the situation when batch rendering.   Here is the image demo:    Does any one know how to avoid that extra render?  Or is this a Blender bug?


I have used Linux on my old PC for a long time without problems. Recently I got a new PC with an Nvidia 1050 GTX graphics card. I tried to install Ubuntu, and the installation seemed to be fine until I restarted the PC and I get a black screen with these messages:  kvm: exiting hardware virtualization


How to fix ./configure command does not exist error on ubuntu 14.10?

I was installing tar.bz2 application (OpenFM) on my Ubuntu 14.10 and I followed steps listed on this website:  .   When I had to run the "./configure" command I saw this:  bash: ./configure: No such file or directory   On this website there were a note if my system does not have the ./configure command I can skip to the next chapter of the guide what contained executing "make" command.   When I executed "make" command without executing "./configure" command I saw this:   make: *** * ***No targets specified and no makefile found.  Stop.     Please answer to me how to fix this error or how to install .tar.bz2 application without "./configure" command.  Sorry for my terrible English and thanks for help!


What polynomials occur in "nature"? I am interested in polynomials of degree three and higher. I am aware of  and .  Edit:  There are some formulas under  category.   I am particularly interested in full polynomials, as opposed to pure power laws. For example $y=at^2+v_0 t + y_0$ for a projectile uses a complete polynomial, while Boltzman law is just a power law.


How would you formally justify this? Or is it just notationally obvious? (As opposed to 'conceptually' obvious, which is never an excuse in mathematics.)  Edit: For some $c \geq 0$  $\text{sup} \ \{ c \cdot f(x): \text{some domain of $x$} \}$ = $c \cdot \text{sup} \ \{f(x):  \text{same domain of $x$} \}$  To illustrate what I mean, consider $\text{sup}\  \{ 1, 5\} = 5$ which however conceptually obvious can still be proven.      Suppose otherwise, if $\text{sup}\  \{ 1, 5\} < 5$, then the supremum   is less than an element of  set. A contradiction. If $\text{sup}\  \{1, 5\} >  5$, then there exists the number 5 less than the supremum   which nonetheless is an upper bound of the set. A contradiction.   But I'm not sure how I would 'prove' my original assertion.


Close javascript popup by clicking anywhere?

I am super novice and need a quick advice. I need the close popup clicking by outside of modal.  Here is the codes. any tips about this?      $('.login-btn').on('click', function () {     $('.signin-parent').show(); }); $('.signin-btn').on('click', function () {     console.log('erhan')     $('.signin-parent').show();     $('.signup-parent').hide(); }); $('.signup-btn').on('click', function () {     $('.signin-parent').hide();     $('.signup-parent').show(); }); $('.exit').on('click', function () {     $('.signin-parent').hide();     $('.signup-parent').hide(); })   It works finely but I click outside of popup it not close, anyone can help me? thanks


What are safe CPU temperatures ranges under heavy load in the unibody Macbook Pro?

I noticed that under heavy CPU load, the temperature differences between the CPU and CPU heatsink are very high:    picture from ; 2.0 GHz quad-core i7 () Sandy Bridge; Macbook Pro   That's a difference of 41°C! Is this safe? Is this normal?  When using the discrete GPU, an entry "GPU heatsink" will show up. The temperature difference between the GPU and GPU heatsink are never more than 10°C. This is why I think that the something's wrong with the CPU cooling.  I have never removed the CPU/GPU heatsink in this Macbook Pro.


GPU rendering causes glass to become extreamly reflective

Does anyone know how to get glass to be transparent. I'm using GPU render to render a bowl and cloth but the GPU and CPU final render have different results on the glass bowl   The top image is using the CPU to render      the bottom one is the GPU.  Does anyone know why this happens and how i can fix it or work around it?  thanks for any help :)


Count the number of specific weekdays between two dates

I would like to count number of weekdays between two dates  For example:  From :1/1/2015 To: 10/1/2015   The number of Mondays = 1


Is there a way to truly delete all deleted files?

I know that on the windows operating system, when you delete a file it's still recoverable.  I'd like to avoid simply paving the harddrive with zeros as I would like to keep my OS installation as is, but is there a way to truly delete files that have been previously deleted?


I have a problem with particles. I can see them in the viewport, but no matter what I do I can't see them in my render. Could anyone of you please help me? I really want to create a snowy scene.   Here's my scene:


QGIS Multiple CASE WHEN/THEN Statements for Expression Based Labels

I am trying to label a single point with multiple labels, based on the attributes for that point.  For example, if one of the attributes is equal to 1, I want to label it with a specific text string; and if another attribute is equal to 0, I want to label it with a different text string, etc.  In addition, I want to use other attribute information to control the placement of the labels around the point, as well as their color.  Can multiple CASE WHEN/THEN expressions be stacked, to achieve the desired result?  I have tried to include multiple WHEN/THEN statements inside my CASE expression, looking like this:  CASE WHEN attribute1 = 1 THEN 'Apple' WHEN attribute2 = 0 THEN 'Grape' WHEN attribute3 >= 0 THEN 'Pear' END   This returns the desired label for attribute1, but ignores the labels for the other two attributes.  I believe this is because a CASE statement can only refer to a single variable/attribute at a time?  If that is true, is there another conditional expression type I can use to achieve what I want?  I'm trying to avoid having to add the point layer multiple times to my project, in order to label based on different attributes.


Is this permutation-sum problem NP-complete?

A new, tighter tardiness bound has been found for global Earliest-Deadline-First scheduling of jobs on symmetric multiprocessors. But this bound seems to be particularly hard to compute. In particular, we were not able either to find a polynomial-time algorithm to compute this bound, or to prove that the problem is NP-hard. In this respect, a sufficient condition for the problem to be NP-hard, is that the following sub-problem is NP-complete.  Given:   a set $\tau$ of $N$ pairs $(C_i, U_i) \in \mathbb{Q}^2$, with $C_i > 0$ and $0 < U_i \le 1$ for all $i \in \{1, 2, \ldots, N\}$, the smallest natural number $M$ such that $\sum_{i=1}^{N} U_i \le M$ (which implies $M \le N$, because $U_i \le 1$), an integer $M'$ with $1 \le M' \le M$, a strictly positive value $b \in \mathbb{Q}$;   does a permutation $\tau' = ( (C_{i_1},U_{i_1}), (C_{i_2},U_{i_2}), \ldots, (C_{i_{M'-1}}, U_{i_{M'-1}}))$ of $M' - 1$ pairs in $\tau$ exist, such that $$   \sum_{g = 1}^{M'-1}\frac{C_{i_g}}{M - \sum_{v=1}^{g-1}U_{i_v}} \ge b   \quad ?  $$  Any suggestion for proving that this is problem is NP-hard, or, on the other hand, for finding a way to solve the problem in polynomial time?


I'm using this template style found here: .  I used Bibdesk to create my .bib file. The citekeys weren't working, I was simply getting [ ?] for every citation, so I replaced them all with hand done references, and am trying to create the bibliography using  \cite{*}. However, it's not creating a bibliography and I'm getting no error messages explaining why.   This is the excerpt from the main.tex file that references bibliographical stuff. I've been reading through similar problems but haven't found anything that worked for me. Thanks for any help!  \lhead{\emph{Bibliography}} % Change the page header to say "Bibliography"  \bibliographystyle{unsrtnat} % Use the "unsrtnat" BibTeX style for formatting the Bibliography  \bibliography{Bibliography} % The references (bibliography) information are stored in the file named "Bibliography.bib" \nocite{*} % pulls everything in the bibliography file.


I'm playing Candy Box 2 and on the Candy Box home screen you can drop 10 candies, I'm already in the room with huge candies and all the dude is doing is eating them, is there something after those candies that he is eating or does he just eat them no matter how many you drop?


Is there a way to move the taskbar to another monitor?

I am using Microsoft Windows XP Professional SP2 and three monitors. I would like for my taskbar to be moved to the third monitor. How can I get it over there instead of on my primary monitor?


IEEE LaTeX style: grouping references together

I'm citing 3 articles together in my thesis and latex displays it as [1; 2; 3], But I want it as [1-3] How can I fix this? Thank you in advance! My M. W. E. and sample bib is attached below \documentclass[12pt,a4paper]{book} \usepackage{cite} \usepackage[round,authoryear]{natbib} \begin{document} \cite{article1,article2,article3} \bibliography{zoteroexport.bib} \bibliographystyle{IEEEtran} \end{document}  @article{soames_detecting_2019,     title = {Detecting {Cycles} in {GraphQL} {Schemas}},     author = {Soames, Kieron and Lind, Jonas},     year = {2019},     keywords = {cycle detection} }


Dior was the second King of Doriath and the son of Beren and Lúthien, so that made him half man, half elf and Maia. However, since Dior died before Manwë decreed any half-blood person could choose which kindred they wanted to be with, what was his fate?  Did he dwell in the Halls of Mandos with the Elves or did he go beyond the circles of Arda like Men do?


How can I turn off or hide animated emoji icons in subject lines in Gmail?

Recently I've been receiving spam and commercial emails that include special unicode characters in the subject line that display as tiny animated icons in the Gmail web app.   on Stack Overflow explains what they are and how they work.  I find the animations extremely distracting when they are displayed in a list of emails by subject. Is there any way to turn them off or hide them?


Will an SPI EEPROM chip have the same issues with non-atomic write operations as a dsPIC's internal EEPROM?

I had some intermittent trouble with the internal EEPROM of a dsPIC. Every so often, some value in the EEPROM would be found zeroed out on power-on. I tracked the problem down to when the chip lost power after the erase step of the write cycle, but before the write had completed. It was all about the timing of the power-down relative to the firmware execution, which was (in normal operation) random. I solved this by adding a buffer section to my EEPROM, to ensure that an incomplete write-cycle could be completed on restoration of power. I had to turn EEPROM writes into an atomic operation.  (For further detail, my buffering technique defines an area of persistent memory that consists of three fields: address to write to, data to be written, and a READY flag. A "write" consists of four steps: write to buffer, set READY flag, write from buffer, clear READY flag. On power-up, you check the READY flag. If it's set, execute whatever's in the buffer. This worked well in internal EEPROM.)  Now I'm using a different dsPIC without internal EEPROM, and I'm trying to use an  to store persistent data. I'm wondering if I should have similar concerns. Should I be worried that my external EEPROM chip will power down mid-write and lose data, and write a fix for this in my firmware like I did for internal EEPROM? Or does the chip itself guarantee atomic write operations?


Monte carlo upsamling for imbalanced data to balance the class before Machine learning algorithm

I have highly imbalanced dataset yes(1440) and No(2.1 lakh ) records for training, I have tried with SMOTE/ADASYN to upsample the imbalanced class and achieved a precision of (0.2% ) , Recall 24 % only for the unseen(test) data. Is there a way to improve precision and recall by any other upsampling method instead of SMOTE/ADASYN. I have heard like Monte Carla simulation in upsampling method can be checked , Can anyone suggest whether Monte Carlo upsampling does well and how it works ?? Is there a way to do it in Python for Monte carlo upsampling.


I 've seen several times "submatrix" in code and manuals. However, whenever I write in my Latex editor, it gets underlined in red, as a spelling mistake. Same things happens now, just as I am writing my first question here. On the other hand, 've gets the same treatment, but that should be just a failure in the spelling checker (because it's not a word).  So, submatrix or sub-matrix? Or none of them, but something else?    EDIT  A related question lies , but it's content is general, so does the duplicate of that question too. Moreover, as explicitly stated there, it depends on the word.


"Your site was unable to contact the Apache Solr server"

We have been using Drupal 6 for 2 years and we wanted to use SOLR to have a better search and index more documents.  I have did everything right with  as per the documentation, my Solr was working fine but I am able to access it on http://localhost/solr/admin.  I have different Solr in different servers, and none work with this Drupal. So I think there is an inherent problem within Drupal, which makes drupal not to find the solr properly.  Previously, I had encountered this issue several times configuring different servers, I am used to reinstall Drupal which made solr work fine but I cant do it to this one because its been running for long with lot of content.  Can anyone help me?


What is the difference between 'house' and 'home'

I am going to home or house  explain difference between home and house with examples


What's a word or phrase to describe a good book that I cannot put down when starting reading?

What's a (big) word or phrase to describe a book that is so good that I cannot put down when I start to read it?


How to convert items from earlier editions to 5th edition?

There's lots of fun stuff in earlier editions, like 3 variants of Excalibur and rainbow armor... How can I convert that stuff to 5th edition?


How to let screen time out on sign in screen

I have Ubuntu 13.10 set up on an older PC. If I am logged in as a user, then the screen timeout and power saving mode works as expected. However, if nobody is logged in, the screen never times out, and the monitor stays on all the time with the login screen.  How can I adjust Ubuntu 13.10 so that the login screen also times out after a minute or so? I don't want the monitor's power saving mode to be disabled just because nobody is currently logged in.


I need something to print the function draw() in one line for all i in the loop. I've searched here, but couldn't find anything.  def many(n):    b = str(n)    c=[]    x=[]    for digit in b:     c.append (int(digit))    for i in range(len(c)):       draw(c[i])


I am new to SalesForce development and don't have much understanding of test classes. Can anyone please help me creating test class for following code

public class GenerateFirstInvoices {     @InvocableMethod     public static void fetchOrderItems(List<Id> orderId) {         List<OrderItem> oproduct = [SELECT Id, Next_Billing_Date__c, OriginalOrderItemId, Payment_Term__c, Quantity, TotalPrice FROM OrderItem WHERE OrderId = :orderId];         for (OrderItem oitem : oproduct) {             switch on oitem.Payment_Term__c {                 when 'Monthly' {                     for (Integer i = 0; i < 11; i++) {                         Proforma_Invoice__c proforma = new Proforma_Invoice__c();                         proforma.Rate__c = oitem.TotalPrice / 12;                         proforma.Amount__c = oitem.TotalPrice / 12;                         proforma.Order_Product__c = oitem.Id;                         proforma.Quantity__c = oitem.Quantity;                          insert proforma;                     }                 }                 when 'Quarterly', '25%' {                     for (Integer i = 0; i < 3; i++) {                         Proforma_Invoice__c proforma = new Proforma_Invoice__c();                         proforma.Rate__c = oitem.TotalPrice / 4;                         proforma.Amount__c = oitem.TotalPrice / 4;                         proforma.Order_Product__c = oitem.Id;                         proforma.Quantity__c = oitem.Quantity;                          insert proforma;                     }                 }                 when 'Semi Annually', '50%' {                     for (Integer i = 0; i < 1; i++) {                         Proforma_Invoice__c proforma = new Proforma_Invoice__c();                         proforma.Rate__c = oitem.TotalPrice / 2;                         proforma.Amount__c = oitem.TotalPrice / 2;                         proforma.Order_Product__c = oitem.Id;                         proforma.Quantity__c = oitem.Quantity;                          insert proforma;                     }                 }                 when else {                     //Do nothing                 }             }         }     } }  Following is my Test class @isTest private class GenerateFirstInvoices_TGN_TEST {     @isTest     private static void fetchOrderItems_TGN_TEST() {         String Payment_Terms = 'Monthly';         Database.SaveResult dsr;         OrderItem drOrderItem;         drOrderItem=new OrderItem(OrderId='802x00000000000AAA',PricebookEntryId='802x00000000000AAA',Quantity=123,Payment_Term__c='Monthly',type__c='Subscription');         dsr=Database.insert(drOrderItem,false);                  Test.startTest();         try{         GenerateFirstInvoices.fetchOrderItems(new List<Id>{dsr.getId()});         }catch(Exception e){}         try{         GenerateFirstInvoices.fetchOrderItems(null);         }catch(Exception e){}         Test.stopTest();                  Test.startTest();         try{                 drOrderItem.Payment_Term__c == 'Monthly';                 Proforma_Invoice__c proforma = new Proforma_Invoice__c();                             proforma.Rate__c = 100;                 proforma.Amount__c = 100;                 proforma.Order_Product__c = '802x00000000000AAA';                 proforma.Quantity__c = 1;                          insert proforma;                      }catch(Exception e){}         Test.stopTest();     }     @isTest     private static void GenerateFirstInvoices_TGN_TEST(){         GenerateFirstInvoices obj = new GenerateFirstInvoices();     } }  Note:- The above test code is just for one condition only The above test class code covers up to for loop, but it does not cover switch statement and as code inside switch. My total coverage is only 30%. Hope it will explain what I need. Please help me in this regard.


Converting/Re-Writing Paper in LaTeX from Word

I have a paper that I wrote in Word with accompanied math equations (for my undergraduate level research paper for mathematics degree) and I just am not at all familiar with LaTeX. I was wondering what resources I could use to get this paper re-written into LaTeX. I will never need to use the program again, so I was really looking for someone who could convert it for me. I would be interested in paying.   If hiring somebody for this isn't an option, could someone maybe help me write it? This program seems like a lot of work where I only have 4 days to get it re-written.


Do I need to leave the Schengen area between two 180-day periods?

I just can't find the answer I am looking for so I hope you can help me!  I am a bit confused because of the new rules from October 2013.  So we are Australian, and were in Schengen between 23/07/14 and 26/09/14 (66 days) and came back in 27/12/14 and the end of the 180 day period is 18/01/15 (23 days) ... so my question is... do we need to leave schengen for the new 180 day period to begin? And then we would get 90 days within the 180 day period?  We are in France, so thinking we could go to the UK or Andorra for a day (I just found out that Andorra is not Schengen, is this true?!)  Or is it that you can spend a maximum of 90 days in any 180 day period, so we couldn't spend 90 days from 20th january because we spent 23 days already (so could only spend 67 days until we need to leave).


With the confirmation of gravitational waves, it got me thinking -- is there an effective elastic modulus for spacetime?   Because the wave propagates, it should be possible I would think to derive a stress-strain relation by determining the amount of length change as a function of force applied.   Has this been done? Is the modulus isotropic or anisotropic (I would guess if it is anisotropic, the anisotropy would be in the time coordinate and the spatial coordinates are isotropic)? Would it be linear or nonlinear?


Which is it? Personal preference, I dislike 'learnt', but it's correct in UK English usage - is that right?


Kubuntu and Windows 7 dual boot, clock time changes automatically

I had windows 7 installed, and I set my PC clock to a specific time. It worked fine but then i also installed Kubuntu (now its a dual boot). Whenever I run Kubuntu my clock changes time by -4 hours and when I again run Windows its time too has changed. So every time i set my clock in windows, Kubuntu changes it by -4hrs and this also effects my windows clock any help?


Let $f$ and $g$ be $n$ times differentiable functions then prove that $$\frac {d^n}{dx^n}(fg)=\sum _{i=0}^n \binom{n}{ i} f^{(i)}g^{(n-i)} $$ where $f^{(k)} $ is $k$-th  derivative with respect to $x $.    Now I started with Mathematical Induction. I know its true for $n=1$ so skipped it. Let it be true for $m<n $ thus $$\frac {d^m}{dx^m}(fg)=\sum_{i=0}^{m} \binom {m}{i}f^{(m)}g^{(m-i)} =s .$$ We need to prove this for $m+1$ . Note that $m+1 <n $ is also true. So we see that  $$\frac {d^{m+1}}{dx^{m+1}}(fg)=\frac {d}{dx}(s).$$ But now problem here is that I don't know how to differentiate this whole $s$ as we cant use Leibniz rule to prove Leibniz rule.


In practice, when entangling two particles (say two electrons), is creating an entangled state purely a matter of bringing them close enough together?  What I mean is, to make their wave functions correlated, is it just a matter of bringing them close enough together (regardless of what is required to accomplish this), or are there other processes necessary to cause the entanglement?


If this is off topic or not allowed please let me know and I will remove it immediately.    I have two sets of documents that I need typeset into LaTeX and graphics computerized (math drawings, graphs, etc).  I don't need them for about another month or so.  Is there anyone on this forum / does anyone know of a typesetter that could do these documents?  Thanks!


Retrieving the filenames from subdirectories

I want to retrieve the filenames of all the files with .xml extension present in various subfolders in a single directory,


To reiterate: Why does array_name[index] == index[array_name] in C++?  I am struggling to find anything online that explains why you can reference an element like this in C++. I have a java background and do not understand the nuances of C++ that well.  Here is an example illustrating the question:  #include <iostream>  using namespace std;  int main() {     int data[3] = {1, 2, 3};     if (data[2] == 2[data])     {         cout << "equal" << endl;         cout << data[2] << ", " << 2[data] << endl;     }     else     {         cout << "not equal" << endl;     } }   Output:  equal 3, 3


Roll a single 6 faced dice as many times as you want to reach a sum X

I am working on a problem where a single dice with 6 face is rolled multiple times to reach a sum of X. This is a combinatorics problem. For example if I just want to find out the number of way a sum of 5 has to be obtained (not including negative numbers) the answer would be (2^4) = 16. Basically it follows the formula 2^(X-1) where X is the sum.   But the above formula is valid when there are the restrictions on the numbers that can be used. In my specific case I have the restriction of a six faced dice (numbers from 1 to 6).  What should be my approach to solve this problem?


Nested footnotes disrupts comma delineation of footnotes

A  has the side effect of abolishing comma delination of sequential footnotes (a feature provided by the footmisc package), as shown below (note the missing comma between footnote 2 and 4):       \documentclass{article}      \usepackage[multiple]{footmisc}     \usepackage{letltxmacro}% http://ctan.org/pkg/letltxmacro      \newcounter{fnmarkcntr}\newcounter{fntextcntr}     \makeatletter     \renewcommand{\footnotemark}{%        \@ifnextchar[\@xfootnotemark          {\stepcounter{fnmarkcntr}%           \refstepcounter{footnote}\label{footnotemark\thefnmarkcntr}%           \protected@xdef\@thefnmark{\thefootnote}%           \@footnotemark}}     \makeatother     \LetLtxMacro{\oldfootnotetext}{\footnotetext}     \renewcommand{\footnotetext}[1]{%       \stepcounter{fntextcntr}%       \oldfootnotetext[\ref{footnotemark\thefntextcntr}]{#1}     }      \begin{document}     This text has multiple sequential footnotes, but comma delination is disrupted %     if one of the footnotes has a nested footnote\footnote{Here is a footnote}%     \footnote{Here is another footnote.\footnotemark{}}%     \footnotetext{This is the nested footnote.}%     \footnote{Here is the third (non-nested) footnote.}.%     \end{document}   Could someone please help me to resolve this problem, so that proper comma delination, per the footmisc package is possible? Many thanks.


How to stop Thunar from being default file browser?

On a relatively new installation, Thunar has become the default file browser simply by using it.   While I can open Nautilus easily enough, I'd rather it remained as the default file browser(especially when I choose to view files in dual pane).  How can I change my default file manager?


A square $10 X10$ is completed with numbers from 1 to 100 such that 2 consecutive numbers are in neighbor little squares.  Show that that on a line or a column there exists more than 2 perfect square.(A perfect square is a positive integer of the form $k^2$)  Looks that there are not too much ways to complete a such square.


Windows 7 running slowly with low CPU usage and memory

I have a relatively new (under 2 yrs old) Windows 7 machine. It has 9GB of RAM, and an i7 core CPU (930 @ 2.8GHz w/ 8 CPUs). After about 8 months since a clean install, I noticed my computer was running slowly. I figure it was fragmentation etc, and I did a complete wipe & clean reinstall.  However, my problems are somehow persisting. The computer is running painfully slowly (but in leaps and bounds - sometimes it will work fine for 3 hrs, then suddenly freeze up just from clicking the start button). The 'freezes' happen randomly - not during any especially intensive computing. I initially thought something might be eating through my CPU and/or Memory, but Task Manager indicates that neither the CPU or Memory spike. In fact, even during serious lag, CPU usage remains at less than 5% and Memory at ~ 1.5GB.  It's beyond me why a fresh install on a powerful machine is performing so poorly. And it certainly is frustrating!  What could be causing the poor performance, and what can I do to fix it?


How do I change a sprite using code from another node?

I'm trying to make a program in Godot where the player can put a bunch of images into a folder, and when the button is pressed, have the image appear as a sprite on the screen. With the current code, the directory for the image is printed when the button is pressed, but the image sprite simply does not appear. No error messages come up either, so I'm stumped as to what the problem is. Here is the code: extends Button  func _pressed():     var cards_order = [] #creates the array          var path = "assets/cards/" #defines a path     var dir = Directory.new() #creates a directory     dir.open(path) #sets the directory to the defined path     dir.list_dir_begin() #begins listing the directory     while true:         var file_name = dir.get_next() #sets the var "file_name" to the next entry in the directory         if file_name == "":         #break the while loop when get_next() returns ""             break         elif !file_name.begins_with(".") && !file_name.ends_with(".import"):         #get_next() returns a string so this can be used to load the images into an array. Also stops .import files from being added             cards_order.append(load(path + file_name)) #loads the next file into the array     dir.list_dir_end()          randomize() #changes the randomization          cards_order.shuffle() #shuffles the array          var card_sprite = cards_order.front() #sets card_sprite as the first item in the array          print(card_sprite.get_path())          $"/root/CardSprite".texture = load(card_sprite.get_path())  Any help with this would be greatly appreciated!


How do I report vulnerabilities in Windows?

I have been looking for vulnerabilities in Windows 8 and Windows 7, and would like to report them to Microsoft.   Some are extremely important including one that compromises the user's key store without asking for the admin's password.   How can I report these vulnerabilities to Microsoft?


Partitioning Guide for Linux. Ubuntu 14.04 LTS

I am new to Linux world and I would like to help me make the best partitioning choice. I am gonna use Ubuntu 14.04 LTS as my main OS on my desktop PC. Basically I use my PC for : coding, surfing Internet, watching movies, listening to music, maybe sometimes playing games.  So help me choose:   What directories will need partitions ? What file system should I use ? What type of partitions should it be ? Logical or Primary ? Should it be on the Beginning or the End of the drive ?


Questions without a question mark (New Yorker)

How to listen to music How a City in France got out the World's first Short-Story vending machines How we learn fairness What makes great detective fiction according to T.S. Elliot What went wrong at St Marks Bookshop   I see that in the New Yorker we have these headlines. Even though they do not have question marks, are these questions? (Specially the first three examples)


Claim the superiority of a treatment in the context of a significant difference with a two-sided test

In the context of a two-sided test, in his book Statistical Issues in Drug Development Stephen Senn writes chapter 13 (Determining sample size), p.201:     if we reject $H_{0}$, the hypothesis which we assert is $H_{1}$, which simply   states that the treatment difference is not zero or, in other words,   that there is a difference between the experimental treatment and   placebo. This is not a very exciting conclusion but it happens to be   the conclusion to which significance in a conventional hypothesis test   leads [...] by observing the sign of the treatment difference, we are   also justified in taking the further step of deciding whether the   treatment is superior or inferior to placebo. A power calculation,   however, merely takes a particular value, $\Delta$, within the range of   possible values of given by $H_{1}$ and poses the question: ‘if this   particular value happens to obtain, what is the probability of coming   to the correct conclusion that there is a difference?’      If we wish to say something about the difference which obtains, then   it is better to quote a so-called ‘point estimate’ of the true   treatment effect, together with associated confidence limits.   From this, I understand that, even if two-sided test alternative hypothesis is non directional, one could determine the direction of the difference by looking at the sign of the estimate difference   But in the previous chapter 12 (One-sided and Two-sided Tests and other Issues to Do with Significance and P-values)p.185, about the statement "Unless we use one-sided tests when comparing a treatment with a placebo, we shall not be entitled to claim superiority of the treatment under any circumstances" he writes:     This argument is not reasonable on two counts (Hauschke and   Steinijans, 1996) [...]   Second, it is obvious that if we test $H_{1\ A}:\mu > 0$ against   $H_{0}:\ \mu = 0$ at size $\alpha/2$ and also $H_{1\ B}:\mu < 0$   against $H_{0}:\ \mu = 0$ at size $\alpha/2$, then since it is   impossible for both hypotheses to be rejected, the probability of   rejecting one or the other given that $H_{0}$ is true is $\alpha/2 + \alpha/2 = \alpha$ . So, by carrying out this procedure we shall   maintain the type I error rate at $\alpha$. Furthermore, we shall   always reject the null hypothesis where the conventional two-sided   test does so, and only reject the hypothesis when this does so. Hence   these two one-sided tests are equivalent to the two-sided test.   Therefore, carrying out a two-sided test and using the results to   determine whether superiority, equivalence or failure to prove a   difference applies is a perfectly acceptable procedure   From that, I understand  that confirmatory directional tests (and hence, multiple comparisons) are needed (and possible) to conclude about the sign of the true difference    $\ $  So here are my questions:   In the context of a significant difference with a two-sided test, is looking at the sign of the point estimate sufficient or not to induce the sign of the true difference?  In the latter case, how does one run a confirmatory directional test in R?   Thanks,   Statistical Issues in Drug Development, 2nd Edition. Stephen Senn © 2007 John Wiley & Sons, Ltd. ISBN: 978-0-470-01877-4 Hauschke D, Steinijans VW (1996) Directional decision for a two-tailed alternative [letter;comment]. Journal of Biopharmaceutical Statistics 6: 211–218.


Python equal operator for finite precision

I need to use Python operator == to evaluate whether the components of two matrices are equal to each other to a specific precision (say only the first three digits is important to me). Is there a way to pass the precision to this operator?


"Group" feature to share knowledge between developers

In my company (as probably in many) we are struggling to share the knowledge. This goes from product-specific knowledge (which would not fit on Stack Overflow) to more broad knowledge like the one related to libraries or  bugs (to name a few possibilities). Once somebody finds a solution to a problem, usually they share it. But it may happen that they forget, or that they way they share it (an email, link on the wiki) is not good enough as users may no check it once the stumble upon the same problem. Probably most of them will just type the error on Google or Stack overflow. Knowing most developers just go to Stack Overflow to check for the issues, it would be worth to leverage this adding a system that facilitated the spread of knowledge in the company. I think it would be handy a system that would allow us to:  Create a list of questions (a private list as public lists are the same as tags) to which a given set of users can contribute adding existing or new questions, where we could search for issues in that list. Tags won't work as questions have a limit on the number of tags and it would pollute the questions with one tag per list, although the idea would be similar (private tags?). That way users have a place to check first of all. Notify members of the lists of new items (an  feed would work) Prioritize results on that list when searching  My questions are:  Do you have any suggestion on how to implement this given the currently available options on Stack Overflow? If it's not feasible, there is any way we can code a solution and contribute it back to Stack Overflow? (I suspect no as I've not seen the source anywhere, but I may have not looked at the proper place) If neither of both would work, how can we suggest this feature for future releases of Stack Overflow? This message is enough?  EDIT: My main point is that tags can be somehow limiting if you have a cross-tag interest. Maybe you can filter all queries with all the tags involved, but doing so will give back results that you may not want (due to quality or not being completely related) and it may be that your interest can't be expressed properly by grouping tags. Also, you may want to keep a set of questions that fit a specific theme relevant to you grouped and easily available. That could be done with the favorite flag. But you may want other people to see that list and  contribute to it questions that fit the theme. That you can't. For example, let's say me and my group are interested on issue that include:  2,  2.5,  3.0, CSS, , HTML5 and . We may find handy to have a list to store relevant questions (project gives error XYZ, why? check there) as it becomes part of a tool you use daily (Stack Overflow). Also, filtering by tags all these concerns would return an empty list, but we want to keep the relation somehow.


I thought this has been asked before but couldn't find it.  In the movie, Rey first scenes included one where she just added water to a pile of powder and poof it transforms into bread.  Out of curiosity, is this a kind of newfangled technology that is already reality on Earth or in the process of becoming so?  Edit: I don't think McDonald's powdered scrambled eggs count...don't troll ok?


Using of Class type variables as generics in Java

I need to pass a series of Class type arguments with associated callbacks to a method without defining additional classes or interfaces.   I tried something like:  void foo(Map<Class, Function> callbacks){     for(Class clazz : callbacks.keySet()){         if(!(callbacks.get(clazz) instanceof Function<clazz, clazz>)){             System.out.println("callback type mismatch");         }     }     //(own logic) }   or  void foo(List<<T>Map<Class<T>, Function<T, T>>> callbacks){     ... }   which is erroneous. Any ideas how to overcome this issue (or why it is not possible without additional classes)?


An application of Poincare inequality [solved]

I am woking on Evans PDE problem 5.10. #15: Fix $\alpha>0$ and let $U=B^0(0,1)\subset \mathbb{R}^n$. Show there exists a constant $C$ depending only on $n$ and $\alpha$ such that $$ \int_U u^2 dx \le C\int_U|Du|^2 dx,  $$ provided that $u\in W^{1,1}(U)$ satisfies $$ |\{x\in U\ |\ u(x)=0\}|>\alpha.  $$ I would appreciate your helping me with this problem.