What is upvoting questions supposed to be for?

I came here to ask "how can we encourage people to upvote questions?".  In the space where I ask and answer (wxpython) there is nine times out of 10 that I come here (daily) a first page of questions with zero or 1 answer, and the only upvoter on any of those questions is me.  I read here at meta a lot of questions about "how can we encourage upvoting?", and many of these are voted down due to people not liking the proposed solution/  But one key point emerges: we collectively don't appear to have a good handle on why upvoting of questions is there.   Or at least, I can't get a clear answer on that which is consistent with the way that it works.  So - what is the purpose of having questions be upvoted?  Just to be clear: I understand what an upvote means.  It means "I think this is a good question".  What I'm not clear on is what is the purpose of this facility in SO?   What is it intended to achieve for the site?    I want to be clear on this, before I think too much about the real thing that was concerning me, which was how to encourage people to vote in this way.  Thanks.  Edit: reponding to "possible duplicate of 'why should I upvote?'", I view this question as different.   That question was "what are the guidelines for upvoting".   My question is "what are the effects that SO wants to achieve with upvoting".  It was observed in comments that the answer to this question is self-evident.   I don't agree.   Possible answers are:  1) To encourage good questions  2) To provide users with a means of getting reputation  3) To make good questions more visible  4) To alert people to not bother looking at bad questions  5) To support decision making algorithms behind the scenes.  I am interested to know what out of these are the primary reasons for making it possible to vote for questions.  What does the SO community view as important objectives.   Because depending one which of these is important, the means by which we would choose to encourage people to upvote questions might be different.  My own observation is that there is no real problem with people downvoting questions - they do this, and achieve objective 4 already.  However, at least in the space of questions where I participate, upvoting good questions is rare, which is what makes this question pertinent.


Is it possible to make it appear to a system that a key was pressed, for example I need to  make A key be pressed thousands of times, and it is much to time consuming to do it manually, I would like to write something to do it for me, and the only thing I know well enough is Python.  A better way to put it, I need to emulate a key press, I.E. not capture a key press.  More Info (as requested): I am running windows XP and need to send the keys to another application.


In , I needed to assume in my answer that $e^{e^{e^{79}}}$ is not an integer. Is there some standard result in number theory that applies to situations like this?   After several years, it appears this is an open problem. As a non-number theorist, I had assumed there would be known results that would answer the question. I was aware of the difficulty in proving various constants to be transcendental -- such as $e + \pi$, which is not known to be transcendental at present.   However, I was looking at a question that seems simpler, naively: whether a number is an integer, rather than whether it is transcendental.  It seems that what appeared to be possibly simpler is actually not, with current techniques.   The main motivation for asking about this particular number is that it is very large. It is certainly possible to find a pair of very large numbers, at least one of which is transcendental. But the current lack of knowledge about this particular number is even an integer shows just how much progress remains to be made, in my opinion.  Any answers that describe techniques that would suffice to solve the problem (perhaps with other, unproven assumptions) would be very welcome.


I have Star N7189 (5.5") with the lower zone of touch screen dead     The menu and back buttons don't work,but the physical home button works.   I tried to press hard on the edges of the screen, I tried to apply a twist from the short sides as if it were nothing but a wet towel. I did the hard reset but it did not work.  Sometimes pressing dead area, the phone takes it as menu button  As well as replacing the screen what other methods can I try? Is there any app, launcher or trick to resize the screen usable only to the working area?  P.S. a few hours after leaving it in airplane mode suddenly the touch had this problem but I do not remember if I inadvertently placed something heavy in that area of the cell.


Looking at the the binding energy per nucleon chart:   I observe peaks for N=4,8,12,16,20,24 while I expected to observe peaks for 2, 8, 20, 28, 50, 82, and 126 because I have heard that in correspondence of these numbers there is the completion of a nuclear orbital, so I expect a local maximum of the stability an so a peak of binding energy.  Is my reasoning wrong?


I happen to see that it is possible to update the Ubuntu image in daily basis. But I don't have the faintest idea on how it is done. Please explain the limits and possibilities in using Jigdo in simple terms.


How can I delete a bunch of folders from a git repo and their history, but preserve the history of every other folder

I have a project that started as a dependency of another project. As such, the coding effort started from within the git repository of the parent project. We should have used a submodule, but it is in the past and can't be helped. Now, this project stands on its own and no longer has dependencies to the parent project. For many reasons, now we want this standalone project on its own repo without references to the original parent project. It is desirable to keep (most) of the commit history. We want to remove all the folders of the parent project and all commits that touched them, but preserve the history and commits of everything of the new standalone project. Is this possible to do? If so, how?


Multiple spans using regex in text in python

I am learning regex. I am trying to get spans of a word in a text as follows:  import re reg=re.compile(r'\b({0})\b'.format('Ipsum'))  text = '''Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.  It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).   Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32.  The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for those interested. Sections 1.10.32 and 1.10.33 from "de Finibus Bonorum et Malorum" by Cicero are also reproduced in their exact original form, accompanied by English versions from the 1914 translation by H. Rackham.'''  print reg.search(text).span()   Trouble is I am able to get only spans of the first location. How do I get spans for all matches of the word


The minimum amount of charge possible is that of quarks. But it also has mass. Why is there no charge without mass? Or is it there?


How to solve $a_{n+1}=a_n+\frac{1}{a_n}$

I know that the limit doesn't exist, using Fixed Point Iteration Method and some appropriate inequalities. I can't think of any way to find the explicit form for $a_n$ from the following recurrence relation. $$a_{n+1}=a_n+\frac{1}{a_n}$$  (If this can be solved, then can $a_{n+1}=ka_n+\frac{l}{a_n}$ be solved?)


Cartesian product of two lists in python letters and numbers


Errors:   Could not execute method for android:onCli                                                          at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick" Caused by: java.lang.reflect.InvocationTargetException Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference at com.stunner.mobicoach.MainActivity.btnAddData(MainActivity.java:152)   ------------------code------------------  public void btnAddData (View v){     String name = etName.getText().toString();     String surname = etSurname.getText().toString();     String position = etPosition.getText().toString();     Person person = new Person(name,surname,position);     persons.add(person);      setTextToTextView(); }


How can i check that string is null or not and while checking condition it throws a null pointer exception

filterType = 0;              if((Name !=  " " &&  !Name .isEmpty() ) |( userName != " " && !userName.isEmpty() ) | userLock == true | (HQ !=  " " && !HQ.isEmpty() ) |  Area !=  0.0  | Route != 0.0 | ( Label != " " && !Label.isEmpty() )){                  filterType = filterType + 1;             }                if( (Phone != " " && !Phone.isEmpty() ) | (URL != " " && !URL.isEmpty()) |( City != " " && !City.isEmpty() ) |  (Date != " " && !Date.isEmpty())| (Email != " " && !Email.isEmpty()) ){                 filterType = filterType + 2;              }    If any of above string contains value then filter type should be added but java throws null pointer exception. How can I fix it?


why not let question authors remove "protected" designation?

It seems that the moderators are too loose with the "protected" designation.  I've seen this with questions asked by others and I've had it done to my own questions.  I've seen a number of questions without any down-voted answers become "protected".  I do realize that some answers may have been removed, but it wasn't the case for at least some of the questions I asked. Which makes it impossible to answer for new users who just joined the communities where the questions were asked.    This is particularly impactful when it happen to questions in lightly-visited communities.  In such situations, a particular question may be interesting, but its author would never see many of potentially good answers which would be given by people joining these lightly-visited communities for the 1st time (often with the specific purpose of answering these questions).  Why not give the authors of questions ability to remove the "protected" designation?  Sort of as a "I can handle bad answers better than no answers" veto?  Edit  After considering the following point made in Catija's answer:      Preventing the bad answers reduces the amount of work that the high-rep users and moderators have to do in order to clean up bad content. You don't get to make others to do this work because you want lots of answers or points of view.   I have to agree with not allowing authors absolute right to "unprotect" questions.  However, in the interest of making the community more helpful, as much as possible, rather than coming off censorial, I will propose a feature request as following:  How about giving authors ability to privately unprotect questions?  A privately unprotected question would mean that "new" users can post answers and they will not be seen by community until the authors gain enough reputation (similar to how this works with upvotes on certain questions right now)?  Question authors should, however, see all answers -- even the ones hidden from the community due to low reputation of those who answer them.  Answers which are not eligible to be seen by the community should not be eligible for moderation, either.  This should reduce the flow of low-quality answers in the direction of moderators.


C++ STL: Custom sorting one vector based on contents of another

This is probably best stated as an example.  I have two vectors/lists:   People = {Anne, Bob, Charlie, Douglas} Ages   = {23, 28, 25, 21}   I want to sort the People based on their ages using something like sort(People.begin(), People.end(), CustomComparator), but I don't know how to write the CustomComparator to look at Ages rather than People.


Tag scores on user profile are not updated again - worth bringing up on meta?

Tag scores on user profile are not updated again. That also happened a few days ago (and lasted 3 or 4 days).  General question though: is it worth bringing it up on meta when it happens? This problem happens from time to time but then resolves itself. It's a minor annoyance really, nothing more, in my opinion.


Is "burning" metals in the Mistborn series the same as digesting?

I wonder if Sanderson ever answered it on any panels. Do the metals simply magically disappear after they are burnt or are they in any way excreted from the body? Do they provide any nutritious value for the allomancers? If allomancers can control what metal they burn, can they also control what foods they burn?


How to check how much time executes javascript function?

I don't know how to do this. Javascript is single-threaded, so I can't run function and timer at the same time. How to check how much time my function executes?


How to deal with implausible answers to filter questions?

I work with a questionnaire that contains a variety of filter questions. In the following I will give an example how one block of this successive questions look like.        Have you ever skipped school in your life? (Yes/No)   If answer is "No", continue with question X on the next page    If answer is "Yes":    Have you skipped school in the last year? (Yes/No)   If answer is "No", continue with question X on the next page  If answer is "Yes":    How many times have you skipped school in the last year? (... times)      The right way to answer this bunch of questions is to respond only to the subsequent question(s) number 2 and/or 3, if one has responded with a "Yes" to the respective previous question (1 resp. 2). If one has answered "No" to one of the first two questions, he or she has to skip the following question(s) and continue with the next block in the questionnaire.  Most of the participants have dealt with this questions in the manner just described. But there are also some who fill in implausible answers. With implausible I mean responding to a question even if this was not reasonable in regard to the filter.  An example:        A respondent admitted that she/he has once before skipped school in his life ("Yes" to question 1).   Following this she/he responded that she/he has not done this in the last year ("No" to question 2).   Nevertheless, she/he incorrectly answered to question number 3. She/He filled in that she/he has played truant 15 times in the last year.        The question is now:  How to deal with these implausible answers to filter questions?  There seem to be three obvious strategies:   Use all information as valid regardless of their implausibility Recode all implausible answers as missing Examine all individual cases that have implausible answer patterns in regard to the filter questions -- see if one can decide on behalf of these informations if the respective answer is really implausible or not     I hope that suggestions can deal with these two issues:    The advantages and disadvantages of the listed (or other) strategies The way a recommended strategy can be realized (if this is not very easy, like in the case of using all information or recoding all as missing)


convert TTL/CMOS output signals to 0V and 5V

Is there an easy way to convert TTL/CMOS output signals to 0 and 5V? For example, if an ic outputs 0.1V as "0", I'd like to convert it to 0V and if it outputs something like 3.9V as "1", I'd like to convert it to +5V. Thanks.


I am trying to extrude faces of a cylinder along local normals. 3dsmax can do it easy, couldn't find how to do it in blender.  The extrude region option extrudes it as shown in the first example. I want it done like the 2nd example.


Normal reaction - force without acceleration

When a body lies on the surface of the Earth it is under the influence of gravity. The force on the body due to gravity causes it to exert a force on the ground and the normal reaction acts in the opposite direction causing the resultant force on the body to be zero.  However, how can the body exert a force on the ground when it does not have any acceleration? Since force equals mass times acceleration how does a body without acceleration experience a force?


Populating dropdown with database entries

I am trying to poulate the database GroupNames in my dropdown using servlets. How to do it? Please help  In my jsp file am having  :    <% ArrayList<String> list1 = (ArrayList<String>)request.getAttribute("res1");  %> <select name="GName" > <%     for(String list:list1)   { %> <option><%=list%></option>  <% }  %>     In my servlet i fetched all the database names in an arraylist like this :      ArrayList<String> list = new ArrayList<String>();             out.println("HI GROUP MEMBER");             String query="Select GNAME from tbGroup";             ps = con.prepareStatement(query);             rs=ps.executeQuery();             while(rs.next()){                 list.add(rs.getString("GNAME"));               }             String[] arr1 = list.toArray(new String[list.size()]);             request.setAttribute("res1",arr1);              int i;             for(i=0;i<list.size();i++){                 out.println(arr1[i]);             }   Now am getting null pointer exception in it.Please help what can be the reason for it ?  Here is complete error :    Stacktrace:] with root cause java.lang.NullPointerException at org.apache.jsp.GroupLoginScreen_jsp._jspService(GroupLoginScreen_jsp.java:91) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:399) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:317) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:204) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:311) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:722)


I know that if events $A$ and $B$ are independent, then $P(A\cap B) = P(A).P(B)$.  Lets say I roll a dice, and define the following events:  $x$ = Number is a multiple of $3 = \lbrace 3, 6\rbrace$  $y$ = Number is more than $3 = \lbrace 4, 5, 6\rbrace$  $z$ = Number is even  =  $\lbrace 2, 4, 6 \rbrace$  Therefore,  $P(x) * P(y)$: 0.166666666667  $P(x \cap y)$   : 0.166666666667  $P(x) * P(z)$ : 0.166666666667  $P(x \cap z)$    : 0.166666666667  $P(y) * P(z)$ : 0.25  $P(y \cap z)$    : 0.333333333333  My question is, why are $xy$ and $xz$ independent events but $yz$ is not? I had expected all combinations of events to be independent as neither events affect any other.


Well, I do not believe that Earth is flat, but I met some conspirationistas believing that all physics we learn in school is twisted, all the Earth's pictures from space are photoshopped by NASA, etc, etc.   So those guys wanted to put a satellite into orbit, take some pics, and see for themselves.   Of course, a satellite won't stay above a flat Earth, but what other very simple means to prove/check that earth is round (well, geoid) do we have?  I am looking for simple means, available to anyone, that do not need any external tool or knowledge that a naysayer would reject.   Some things I've considered:   Meteorological balloon with camera and a phone with GPS, with a parachute to recover it. It has been done by amateurs, and in good conditions, you can see the Earth's curvature. Measure the Sun's height above horizon at noon at two different latitudes. The difference, along with some simple geometry would give you Earth's diameter.


I'm trying to insert an empty string in a non-nullable column in Oracle but fails. Here's the case:  create table trademark (   name varchar2(100) not null );  insert into trademark (name) values ('Kodak');  insert into trademark (name) values (' '); -- one space  insert into trademark (name) values (''); -- empty string Error: ORA-01400: cannot insert NULL into ("USER1"."TRADEMARK"."NAME")   What am I doing wrong?


What is the difference in meaning between the sentences?

"She works in the paper business." "She works in paper business."


Is it ethical to profit by having my students buy my textbook?

This question was suggested to me by  which asked about the practicalities, but attracted many comments about the ethics.  So this question is to ask about the ethics directly.  Suppose I have written and published a textbook, and I want to use it as the text for a course I am teaching.  I receive royalties from each copy of my book that is sold, so if my students are required to buy my textbook for the course, I will make some money.  Is it ethical to do so?  Well-reasoned opinions would be useful answers, but even more useful would be pointers to institutional policies, professional codes of ethics, etc, that address this issue.  Of course, there are many ways to avoid profiting from the sale of my book to my students.  If my contract with my publisher allows it, I could distribute PDFs to my students, or have the university bookstore print out copies and sell them at cost.  Another approach I've heard of is to compute how much I earn in royalties on each copy, and refund that amount from my pocket to each student who buys a copy.  Or, use my royalty earnings to buy pizza for the class.  Certainly these are nice gestures, but I would like opinions on whether they are ethically required.  Edit: To address some questions that have arisen in the comments:   This question is hypothetical.  I haven't published any textbooks myself and have no immediate plans to do so.  In any case, my personal preference would be to make the book available to students for free, if at all possible.  So I've phrased this question in the first person for rhetorical convenience only. I had intended the question to be only about the potential financial conflict of interest that could arise if I make money by assigning my own book.  Some of the answers feel that it is improper for me to assign my own textbook at all, whether I make money or not, but I don't think this point of view is prevalent within the academic community.  If it happens that my book (as a pithy but now-deleted comment put it) "blows", I think most would agree that my decision to assign it is pedagogically unfortunate, but not unethical.   I don't literally mean that students would be required to buy the book, only that they'd be expected to have it.  I might assign readings or homework problems from the book, so that the student needs access to the book in order to do them, but they could certainly achieve this by getting a used copy or borrowing from a friend.  But probably most students would buy new copies anyway, since that is the most convenient way.


in the Death Note states:        Whether the cause of the individual's death is either a suicide or accident, if the death leads to the death of more than the intended, the person will simply die of a heart attack. This is to ensure that other lives are not influenced.      However,  states:        Even though only one name is written in the Death Note, if it influences and causes other humans that are not written in it to die, the victim’s cause of death will be a heart attack      Besides the fact that I find these 2 rules to be contradicting (correct me if I'm wrong), it still made me curious: Is it possible to kill people indirectly with the Death Note?  For example, writing a heart surgeon's name during a operation, or a pilot's name while mid-flight.


How many continuous function $f(x)$ exist such that $\int_{0}^{1}f(x)\big(1-f(x)\big)\mathrm dx = \frac{1}{4}$?

How many continuous function $f(x)$ exist such that $$\int_{0}^{1}f(x)\big(1-f(x)\big)\mathrm dx = \frac{1}{4}\text?$$ I want to find the number of such functions but I don't know how to proceed. It would be of great help if someone can tell me which theorem to apply or provide with any other hint. Any help is highly appreciated.


Get number of frames in scene from the command line?

I'd like to know if there is a command-line option (or combination, or a way!) to get the number of frames that are included in a specified blender scene; for example I'd like to use is like this:  $ blender <option> file.blend $ Number of frames in blender scene: xxxx


I just bought a 120mm deep cool fan with a rating of 12v, 0.07A (70 mA)= 0.84watts  Currently I only have a 12v 2.5A (2500mA) DC adapter.  I'm a complete noob in electricals...so the question is-  Can i use that adapter to power my fan?..is the power too high and will it burn the circuitry inside the fan...or is it ok to use that adapter. Should I buy another adapter that matches the ratings of the Fan?  Thanks in advance.


How to Make up for Mediocre STEM GPA? Will Postbac Help?

I am a senior in college majoring in cognitive science and considering grad programs in neuroscience/cognitive science. Long story short, I didn't do super well in a lot of the STEM classes I took. Specifically, I got a B- in intro programming and C+ in intro computer science, C in gen chem (A- in lab though), and C- in orgo. I've gotten B's and B+'s in every math class I took (intensive intro stats and calc up to multivariable).  I've gotten A's in most major classes (related to cog sci), A-'s and B+'s in biology classes.   Overall, my GPA is hovering around a 3.3.  I definitely tried hard in my classes- I think some of the bad grades are due to mental health struggles related to personal and family crises, others due to me turning in problem sets late (i.e. would've gotten A's on most of them but got points off for lateness). So the problem was rarely me struggling with the material.   I don't feel confident in terms of applying to grad school, so I'm seeking advice from anyone who's been in a similar position. Can a good GRE score, research experience, and good rec letters make up for these bad grades? Will I need to do a postbac or something extra to enhance my chances of getting into a neuroscience/cognitive science PhD program?  Also, will the fact that I am at Yale make any difference or not really?  Thanks!


Cannot enable or find option to enable GPU

i just started using blender recently and wanted to render an animation made with my gpu cos it was taking ages with the cpu. I went to user prefrences to enable the gpu but the cuda option wasnt there for me to click.(i have a Intel(R) HD Graphics 3000 gpu if that matters) also im using cycles


Should clicking a checkbox in an indeterminate state check it or clear it? Why?

Below I have provided an example of a checkbox group including a parent checkbox in an indeterminate state. Some of the child nodes in the Tall Things tree are selected and some are not, therefore Tall Things is presented in an indeterminate state:    When the user clicks on the indeterminate checkbox, what should happen? Should the checkbox be checked, or should it be cleared? More importantly, why?


number of real solution of logarithmic and exponential equation

Number of real solution of $$\log_{\frac{1}{16}}(x) = \left(\frac{1}{16}\right)^x$$   $\bf{My\; Try::}$ Using hit and trial Here $\displaystyle x= \frac{1}{4}$ and $\displaystyle x = \frac{1}{2}$ are the solution of above equation.  Now for the existance of other solution, Let $$f(x) = \log_{\frac{1}{16}}(x) - \left(\frac{1}{16}\right)^x$$  So $$f'(x)=\log_{\frac{1}{16}}(e)\cdot \frac{1}{x}-\left(\frac{1}{16}\right)^x\cdot \log_{e}\left(\frac{1}{16}\right)$$  And $$f''(x)=-\log_{\frac{1}{16}}(e)\cdot \frac{1}{x^2}-\left(\frac{1}{16}\right)^x\cdot \log^2_{e}\left(\frac{1}{16}\right)$$  Now for $\max$ or $\min,$ Put $$\displaystyle f'(x)=0\Rightarrow \log^2_{\frac{1}{16}}(e) = x\cdot \left(\frac{1}{16}\right)^x$$  Now how can i calculate after that, Help required, Thanks


HP Pavilion with Ubuntu 16.04.5 WiFi not working

I have a brand new HP Pavilion x360 convertible with a fresh install of Ubuntu 16.04.5.  The WiFi is not working; none of the WiFi networks are even showing up. Ethernet is also not working; if I plug in an Ethernet cable is shows up as 'wired network 1' but when I try to connect to it it fails.  This is part of the output from running lspci: Network controller: Realtek Semiconductor Co., Ltd. Device b822  I think the issue is that the network controller is too recent and doesn't have Ubuntu support yet. I'm not sure how to fix this as without internet connection I can't download new WiFi drivers.  None of the solutions that I found online worked for me. Can someone help me to resolve this issue?


I can't resize my partition using gparted

I noticed that there are a lot of questions similar to mine on here, but I couldn't find the one that solves my issue. I have posted the image below:    I want to increase /dev/sdb12, but it won't let me use the allocated space, what should I do in this case?


We know that the ways to go from A to B in a $m×n$ rectangle is $\frac{(m+n)!}{m!n!}$.  then find ways to go from $A$ to $B$ just by using this formula.(shortest way)     My Attempt:I calculated the $4*4$ square ways there are 70 ways now we should reduce the ways that should'nt calculated.Can you help me please??


Show that a ring $R$ is a division ring if and only if, for each nonzero   $a\in R$, there is a unique element $b\in R$ such that $aba = a$.    $\Rightarrow$ Assume $R$ is a division ring. Let $a\in R$. So there exists $a^{-1}$ such that $aa^{-1}=1=a^{-1}a$. So $aa^{-1}=a^{-1}a$.   Now I am not sure to find a $b$ such that $aba=a$?  $\Leftarrow$ Assume $aba=a$ for nonzero $a\in R$. Let $r\in R$ such that $ra=1$. Then $a=aba=a(ra)=(ar)a$ so $ar=1$. Therefore $r$ is the inverse of $a$ and so $a$ is a unit and $R$ is a division ring.  This hinges on the fact that $ra=1$, is that something I can say?


Seeking up to date Italian administrative boundaries?

I am after Italian GIS data - administrative boundaries such as:     Regions (Regioni) Provincies (Provincie) Municipalities (Comuni) Districts (Quartieri) City quarters (Contrade o Rioni) Zones (Zone) Suburbs (Frazioni)  and Postcodes.  I can find data some data to download - for example     But I want to make sure I have the most up to date data.  Who is the official supplier of this data? Which government department manages this GIS data? When the data is updated how will I know?  In Australia  there is a government department that manages this data and every 3 months we are are sent updates if we pay some $. I am not sure if there is an equivalent in Italy


Is it true that $(R\times S)[G]\cong R[G]\times S[G]$?

I know for two groups $G, H$ (not necessarily finite) we have $R[G\times H]\cong (R[G])[H]$, but I was wondering if we had a similar statement for rings $R,\,S$. In other words, if $R,\,S$ are two (possibly noncommutative rings), is it true that $(R\times S)[G]\cong R[G]\times S[G]$?


Why is gravity still considered a fundamental force?

Einstein's geometry is often explained to the layman (me) as "Mass tells spacetime how to curve, spacetime tells mass how to move". It seems to me then, that what we call gravity is explained by the movement of a body in a straight line through curved spacetime.   I understand from similar questions that it's a model, we use the apparent force of gravity because it's easier to model a force than model curved space,   The standard model of particle physics explains the other 3 fundamental forces and the particles that carry them. However it can not explain gravity as a force in the same way, and the predicted graviton hasn't been detected by any of the particle accelerators.  In light of the fact that it is explained by the curvature of space, that it isn't explained by the otherwise well tested model of particle physics, that it is completely different from the other 3 fundamental forces in magnitude, why is it still considered to be fundamental?


Copy the entire contents of a directory in C#

I want to copy the entire contents of a directory from one location to another in C#.  There doesn't appear to be a way to do this using System.IO classes without lots of recursion.  There is a method in VB that we can use if we add a reference to Microsoft.VisualBasic:  new Microsoft.VisualBasic.Devices.Computer().     FileSystem.CopyDirectory( sourceFolder, outputFolder );   This seems like a rather ugly hack. Is there a better way?


I'm making a billboard design - 400 cm wide + 300 cm high + 50 mm bleed. Cause the file is too big to make it in original size, I'm gonna make it in 1:10 ratio. So that means 40 cm x 30 cm + 5 mm bleed. I want to put a picture on the billboard - is it enought if I put a picture with 300 dpi? And the font - do I have to create outlines? I'm afraid of how it will look, when they will stretch everything to 300 x 400 cm. And I didn't get much information from the print shop, so I'm on my own..   Thanks for the info :)      The billboard is 10 meters away from the road, so people mostly only drive by. The picture I want to use is W=16,93 cm and H=11,12 cm and 2000 x 1324 px. But the picture is only for the background, so the billboard doesn't look so plain. And the picture is blurred. But there a still some details of the bearings and I don't want to loose them on the print.    Webster you are talking about dpi, and mnxd you are talking about ppi. When I open my photo in Photoshop - the image size shows me the photo resolution is 300 Pixels/Inch, but when I have the same photo in Illustrator it shows me - PPI: 124 .. Now I'm a bit confused..


How to send notification based on host and not service in Nagios?

Who that gets notifications are defined in the service and host definitions, but what I would like is that it is only defined on a pr host level.  So whoever that is in the contact_groups for the host also get all service notifications.  For this particular host definition example would I like the groups admins and sandradebug to receive all host and service notifications.  Is that possible?  Typical host definition  define host {   use                     linux-host   host_name               example   alias                   example   address                 10.10.10.10   hostgroups              default-linux-services   contact_groups          +sandradebug }   Service check that all Linux hosts get  define service {   use                     generic-service   name                    check_disks   service_description     Check Disk   check_command           check_nrpe!check_disk   contact_groups          linux-admins   hostgroup_name          default-linux-services }   Don't know what this does, or why it is required  define hostgroup {   hostgroup_name  default-linux-services   alias           All Linux hosts shall have these service checks   members          }   Service template  define service{   name                            generic-service   active_checks_enabled           1   passive_checks_enabled          1   parallelize_check               1   obsess_over_service             1   check_freshness                 0   notifications_enabled           1   event_handler_enabled           1   flap_detection_enabled          1   failure_prediction_enabled      1   process_perf_data               1   retain_status_information       1   retain_nonstatus_information    1   is_volatile                     0   check_period                    24x7   max_check_attempts              3   normal_check_interval           10   retry_check_interval            2   contact_groups                  admins   notification_options            w,u,c,r   notification_interval           60   notification_period             24x7   register                        0 }


Why would using new and constuctor functions in JavaScript be wrong

I have seen some articles and some claims on answers in SO questions that using new and constructor functions is wrong and should not be used.  They go against the prototype nature of JavaScript.  Could someone please enlighten me and show a situation where using new and constructor functions is so bad it should never be used?


how do I give the client access to remoteapp but prevent ts login?

I am running windows 2008 and have published an app with remoteapp in terminal services. That works great.   My question is, can I prevent the user from logging in to the server with rdp while still allowing them to access the remoteapp?  Thanks!


Downloaded images failed checksum validation   I tried to install Ubuntu on a Nexus 7. I have tried several times in the last month. I followed all directions to the letter, and went through all the troubleshooting steps. I Re-downloaded the Ubuntu Core Nexus 7 installer, but I still always get the above notice.  Any suggestions?


I currently have to use Gnome 3 , so I don't have the handy shortcuts like [super] + 2 opening the second application (Firefox) in my launcher available.  What I want to do, is a to create custom shortcuts for these. Which command do I have to execute to in order to started Firefox if it isn't running and switching to the window of Firefox if it already is running?  Firefox – of course – only is an example. But it's the program I care most about. Ideally, it should also work with Evolution and Nautilus / Nemo.


How do I redirect www to non-www in Route53?

I host my site at domain.com.  My DNS entries in Route53 are as follows:  domain.com      A       xxx.xxx.xxx.xxx      300 domain.com      NS      stuff.awsdns-47.org  172800 domain.com      SOA     stuff.awsdns-47.org  900   I would like to redirect traffic from www.domain.com to domain.com, as currently this just returns a 404.  suggested a PTR record, and I added that:  www.domain.com  PTR     domain.com           300   but it didn't work. What should I be doing?


Can I catch Groudon after defeating him?

I have only been a pokemon trainer for about two weeks, so I admit that I lack the experience of a veteran trainer. However, I have already defeated the eight gym leaders in my region (including my father!) and disrupted the criminal actions of a group of scientific thug fanatics.  Despite my obvious natural talent, I feel like I have made a blundering mistake. In my eagerness to save the world from the aforementioned apocalyptic extremist group, I defeated their cataclysmic Primal Groudon without a moments hesitation. It was then I realized the unfortunate selflessness of my actions--I should have captured the beast for my own use!  I returned to the Cave of Origins, but I can't find him in either of the two placed I confronted him earlier. Is there any way to re-encounter this leviathan, or have I entirely wiped the legend from the face of the earth?  Thanks in advance!


Hi there! I'm looking for a help drawing this diagram. Any ideas?


Deriving transition matrix from infinitesimal generator, continuous time Markov chain

I' am reading  by Lawler and I' am a bit confused how demonstrates you get the transition matrix $\textbf{P}_t$ from the infinitesimal generator $\textbf{A}$. I'll provide the example in the book:  $\textbf{Example 1.}$ Consider a chain with two states, (0,1). Assume $\alpha(0,1)=1$ and $\alpha(1,0)=2$. Then the infinitesimal generator is  $$\textbf{A}=\left[\begin{array}{cc} -1 & 1 \\ 2 & -2 \end{array}\right]$$  In order to compute $e^{t\textbf{A}}$, we diagonalize the matrix. The eigenvalues are 0, -3. We can write  $$\textbf{D}=\textbf{Q}^{-1}\textbf{A}\textbf{Q}$$  where  $$\textbf{D}=\left[\begin{array}{cc} 0 & 0 \\ 0 & -3 \end{array}\right],\textbf{Q}=\left[\begin{array}{cc} 1 & 1 \\ 1 & -2 \end{array}\right], \textbf{Q}^{-1}=\left[\begin{array}{cc} 2/3 & 1/3 \\ 1/3 & -1/3 \end{array}\right]$$  We use the diagonalization to compute the exponential $e^{t\textbf{A}}$.  \begin{align} \textbf{P}_t&=e^{t\textbf{A}}=\sum_{n=0}^{\infty}\frac{(t\textbf{A})^n}{n!} \\ &=\sum_{n=0}^{\infty}\frac{\textbf{Q}(t\textbf{D})^n\textbf{Q}^{-1}}{n!} \\ &=\textbf{Q}\left[\begin{array}{cc} 1 & 0 \\ 0 & e^{-3t} \end{array}\right]\textbf{Q}^{-1} \\ &=\left[\begin{array}{cc} 2/3 & 1/3 \\ 2/3 & 1/3 \end{array}\right] + e^{-3t}\left[\begin{array}{cc} 1/3 & -1/3 \\ -2/3 & 2/3 \end{array}\right] \end{align}  What I don't understand is what the second to last line is not,  $$\textbf{Q}\left[\begin{array}{cc} 1 & 1 \\ 1 & e^{-3t} \end{array}\right]\textbf{Q}^{-1} $$  Though I tried it out and it would not provide a valid stationary distribution.


I'm trying to make an action on Automator that recursively batch  processes PNG images using bash shell script with pngquant  I have done this on terminal and got no problem, but now I want to make a finder action using Automator.  This is the shell script code (receives a directory input):  directory="$1" cd $directory find . -name '*.png' -exec pngquant --ext .png --force 256 {} \;   I'm having trouble with pngquant as it says:   pngquant: command not found


I have a school assignment on immutable generic Binary Search Trees in java. I have implemented all of the basic BST functions but we are also asked to create a saveInOrder function that takes a generic array of type Entry that should be modified in the function to contain all of the Entries in order of the value of their key.  We are given an interface to implement, and in that interface there is a method signature   public void saveInOrder(Entry<Key,Value> a[]);   I'm confused as to why the [] brackets are after the 'a'? Shouldn't it be  Entry<Key,Value>[] a?   Also, will the array passed to this function have a size defined already? I googled generic arrays and have realised they're a tricky topic. Any explanations would be great thanks! Sorry if it's a little ambiguous


Is there one global visa that lets you enter (almost) any country?

Is there a one visa or any paper that lets you enter (almost) any country in the world? For example, you are trusted and record-free citizen of couple countries and you sign something that makes you allowed to enter (almost) any country.


$f(z)=\frac1{2\pi i}\int_{\Gamma}\frac{f(\zeta)}{z-\zeta}d\zeta$ if $\lim_{z\to\infty}f(z)=0$ and $f$ is analytic in $|z|\ge1$

Let $f$ be analytic in $|z|\ge1$ and  $\lim_{z\to\infty}f(z)=0$. Then is $f(z)=\frac1{2\pi i}\int_{\Gamma}\frac{f(\zeta)}{z-\zeta}d\zeta$,$\forall |z|\ge2$, where $\Gamma$ is the circle of radius $2$ with centre at the origin.   I think yes, by the Cauchy integral formula. But, how do we ensure that the non analyticity of $f$ in $|z|<1$ dosent affect the formula? Thanks beforehand.


This is a question I had on an exam so there is no access to calculators or software. I checked the answer using Maple after and as expected, the answer is very large and some of the prime factors are also very large, with over 10 digits.   Is there any reasonable way to break this down and get an answer of some sort?


Gnome-Software in Ubuntu 16.04 is partially loading, and I can't install software and only appears the core package in software installed, and I can only find the software of the core packages.  Does anybody know how to fix this?


Prove that $\gcd(g_a,g_b) = 1$ given that for $n \in Z^{\geq 0}$, define $g_n = 2^{2^n} + 1$. I have already proved that $g_0\cdot g_1\cdots g_{n-1} = g_n -2$ if this hint is useful in this proof.


cfr once asked and answered the following question:   In short: every run of xindy/texindy on an actual file (not the help menu) does end with something like  /usr/local/texlive/2017/bin/x86_64-linux/xindy.run: error while loading shared libraries: libncurses.so.5: cannot open shared object file: No such file or directory   The problem is that the given solution does not work anymore nowadays. Running an up-to-date TeX Live 2017 (vanilla) and Arch Linux x64 with access to AUR I tried to use the packages given in the answer. Unfortunately both cannot be validated and even skipping the signature check does not help.  Probably it could work compiling xindy manually against another library, but where are the official sources with version 2.5.1 (or newer)?  Or is there maybe another way of getting xindy to work on a "modern" OS?  Update: I've tried to compile the ancient sources from 2010 from  (CVS) where any essential binaries and code files are from 1996 (no luck). And the xindy home page talks about xindy 2.2 being a release candidate, although TeX Live 2017 ships with xindy 2.5.1.  Update 2: As @DavidCarlisle showed in the chat the usual behavior would be  $ xindy --version xindy release: 2.5.1 xindy script version: 1.18 xindy kernel version: 3.0 CLISP version 2.49.50 (2017-03-19) (built on desktop-new [192.168.1.4])     architecture: X86_64   Because of the missing library the kernel version and the clisp version do not even show up.


How can I help LaTeX with the linebreak?  \documentclass{scrartcl} \usepackage{url}  \begin{document}  I hace a book\footnote{\url{http://www.mazon.de/product/publikationen/hochschulschriften/standard-for-die-exakt-calculation-uncollered-uninfinite-word-finding-smaschinen-28-3-2014.html}}.  \end{document}


Creating ArcGIS 9.3 geodatabase in ArcGIS 10?

Dooes anyone know if it's possible to create a v9.3 geodatabase from ArcGIS 10?   Opening them is not a problem, but I haven't found a way to create one without going back to 9.3 and doing it there.


Can't disable Windows Defender by using group policies

I have recently installed Win 10 Pro. No matter how many times i try to disable Defender Antivirus with Group Policy Editor (Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus) by activating the policy "Turn off Windows Defender Antivirus" and clicking OK, Windows just ignores all my attempts and revert it back on like nothing happened... It just turns Turn off Windows Defender Antivirus from enabled back to Not configured When i close gpedit and open it back again i can see it's back to Not configured Tamper Protection is off ... I've been using PC's for 25 years without Antiviruses by using only common sense and Process Explorer. Why is Microsoft forcing me to use something i don't want on my own computer?


Several of my ubuntu apps arent opening at all

Most of the apps that I currently need aren't working, even after restarting several times and trying many online suggestions. It started when I tried upgrading from Ubuntu 18.10 to 19.04. I opened the software updater and it gave me an error about my python3 file being corrupted or something similar. I found a guide on how to fix this and i ran the following command: sudo ln -sf /usr/bin/python2.7 /usr/bin/python but I realized that was for a different version of python(after I ran it). When I tried to open the software updater again, it wouldn't open. I looked up solutions to start this from terminal or other places, but found that the terminal didn't open either. I don't know what's happening, and I'm too much of a linux noob to fix it, so I'm asking on here.


Can a CDF from data cross with another CDF

Given two data sets of positive real numbers X and Y, both of the same size, and 0<=Y<=X for each row; can the empirical CDF of X ever cross the empirical CDF of Y?


Inverse limit of rings of polynomials in many variables

I am trying to understand inverse limits and so I decided to try and compute one of such limits. We are going to work in the category of rings. Let $R$ be a ring. First, I set up an inverse system. Let $A_i:=R[x_1,\dots,x_i]$ denote a ring of polynomials over $R$ in $i$ indeterminates and let $f_{ij}:A_j \rightarrow A_i$   be morphism sending $x_j,\dots,x_{i+1}$ to $0$ and $x_1,\dots,x_i$ to themselves. Then $((A_i)_{i \in \mathbb{N}},(f_{ij})_{i \leq j \in \mathbb{N}}$) is my inverse system. Then, according to , the inverse limit $A$ of our inverse system is   \begin{equation*}A=\underleftarrow{\text{lim}}A_i=\Bigg\{\overrightarrow{a}\in\prod_\limits{i \in \mathbb{N}}A_i|a_i=f_{ij}(a_j) \; \forall \; i\leq j \in \mathbb{N} \Bigg\}. \end{equation*}   So if we look at some elements of $A$ (take $R=\mathbb{Z})$ we have, for example:  \begin{equation*} (\dots,3x_{3}^4-5x_3x_2x_{1}^2+5,5,5) \; \text{or} \; (\dots,x_{3}+x_2+x_1+4,x_2+x_1+4,x_1+4) \end{equation*}.   My suspicion is that $A \cong R[x_1,x_2,\dots]$ and so the inverse limit would be just that with nutaral projections. Is that correct? Is this the right way of looking at these sort of constructions?


Derivative of a function with respect to another function.

I want to calculate the derivative of a function with respect to, not a variable, but respect to another function. For example: $$g(x)=2f(x)+x+\log[f(x)]$$ I want to compute $$\frac{\mathrm dg(x)}{\mathrm df(x)}$$ Can I treat $f(x)$ as a variable and derive "blindly"? If so, I would get $$\frac{\mathrm dg(x)}{\mathrm df(x)}=2+\frac{1}{f(x)}$$ and treat the simple $x$ as a parameter which derivative is zero. Or I should consider other derivation rules?


NPN is physically symmetrical yet the model isn't?

It just strikes me as very odd that all representations of the actual physics of NPN transistors in textbooks is perfectly symmetrical, yet neither the diagram used to represent them nor the mathematical model used to simulate them seem to reflect that.  Could someone explain where and how the symmetry disappears when going from the physical model to the mathematical one ? Is that asymmetry not important enough that it's just not worth depicting it ?  Here's an example of what I mean :    (source: )


ArcPy: Distortion towards edges when exporting to TIFF

I am writing a function to zoom to selection (based on a criteria) and Exporting it to TIFF.  The problem I am getting is that the when I load the exported TIFF image in Map, I am seeing distortion towards the edges (perfect near the center). Can someone help me with what am i doing wrong in this case. Attaching my code below:  def SelectDataZoomSelected(mpath, fpath, cond, opath):  # Import system modules import arcpy  mxd = arcpy.mapping.MapDocument(mpath) df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0] lyr = arcpy.mapping.ListLayers(mxd, fpath, df)[0]  # Use the SelectLayerByAttribute tool to select and zoom to the selection arcpy.SelectLayerByAttribute_management(lyr, "NEW_SELECTION", cond) df.zoomToSelectedFeatures()  # Export the map to a TIFF arcpy.mapping.ExportToTIFF(mxd,opath,df,640,480,96,'TRUE','24-BIT_TRUE_COLOR','NONE','TRUE')  # Clear the selection and refresh the active view arcpy.SelectLayerByAttribute_management(lyr, "CLEAR_SELECTION") arcpy.RefreshActiveView()  del mxd


I have a question that where can I see the md5sum to check my file? Yes, I know there is one in the iso file, but it cannot do any thing! If the file has been change by a attacker, he  will change the file either! Another problem is, the page show md5sum is on a http connect, not https, so I still cannot make sure it work.


A Sequence converges to a limit $L \in \mathbb R$ if, and only if, an $N$-th tail of the sequences converges to $L$ for some $N \in \mathbb N$

I want to show that a sequence $(a_n:n \in \mathbb N)$ converges to a limit $L \in \mathbb R$ if, and only if, an N-th tail of the sequences converges to $L$ for some $N \in \mathbb N$. For each $N \in \mathbb N$, an N-th tail sequence can be defined as $(t_n:n \in \mathbb N)$ where $t_n := a_{N+n}$.  Using the definition of a limit for the sequence $(a_n:n \in \mathbb N)$, we have the following:  For every $0 \lt \epsilon$, there is a natural number $N_{\epsilon} \in \mathbb N$ such that for all $N_{\epsilon} \lt n$, $|a_n - L| \lt \epsilon$. But I'm not sure what to do next in order to show that the $N$-th tail converges. Which natural number should I choose for the $N$-tail? Any help would be much appreciated.


What is the single word that describes a person who always gossips? (For example, telling things about others which are not true.)


Was Luke Skywalker the leader of the Rebel forces on Hoth?

Rewatching Star Wars: The Empire Strikes Back, I noticed the opening crawl declares Luke Skywalker as the leader of the Rebel forces on Hoth:     Evading the dreaded Imperial Starfleet, a group of freedom fighters   led by Luke Skywalker has established a new secret base on the remote   ice world of Hoth.   Is that correct? I though Princess Leia or General Rieekan commanded the Rebel base on Hoth.  I can't find any references to this discrepancy on the Internet. Maybe in an earlier version of the script, Luke Skywalker was the commander and the crawl wasn't updated. Or perhaps "led" is meant in the sense Luke was a moral leader of the Rebel fighters?


How to I used or access the list inside the function to another function?

Let's say I have this two functions:  lst = [] def function1(request):     lst = ['12','10']     return HttpResponse(...)  def function2(request):     qry = SampleModel.objects.filter(id__in=lst)     return HttpResponse(...)


Printing the time between 2 points in a program in Python

I would like to know a way to time between two points in a program. In my situation I will ask the user 10 questions and after display the time it took for them to answer the question (example code below). How would i do this through something like import time ?  Example code:  timer.start question1 = input("What is your favorite game ?") timer.end print(timer.time)   ^ The timer.x thing is going to be replaced with your suggestions.


Why don't banks give access to all your transaction activity?

In the era of big data, I find it surprising that banks and credit card companies only offer access to a ridiculously small number of transactions - often only your last 180 days, if that. The longest I've seen was 720 days going back. I suspect they do store everything, but intentionally limit access.  These transactions are text only, take up extremely little space, and storing an individual's lifetime worth of transaction would take less than 10MB of data; about the storage required by two MP3 files, and about 250k records per person per lifetime, if we generously assume everyone makes 10 transactions a day. But I'd be happy with only the last 10 years of transactions, so about 1MB per customer. One of the largest banks, JP Morgan Chase, has . That means 70TB of data for 10 years of records - hardly impressive for a corporation of that size, with , when .  By comparison, would you put up with Gmail or any online email provider keeping only the most recent 120 days worth of email? (And emails do take a lot more space than transactions, are far more numerous, and have to be instantly retrievable.)  Storage requirements for transaction activity are trivial in an era where we're throwing around petabytes and zetabytes.  Is there a sound reason for banks not offering access to all your transactions, other than legacy software on their side?      UPDATE: Somehow I hadn't found  asking the same thing.


What do you call a person who started something that is later followed by everyone? For example, someone started to stay late at night till 8 p.m. and later everyone started to stay till 8 p.m..


I am supposed to write a manuscript based on apa6. Unfortunately I am located in Germany, so my professor wants to have 2 (!) abstracts - one in English ("Abstract" - as implemented in apa6 already) and an additional one, called "Zusammenfassung" (literal translation into German).  Does anybody have an idea how to get this done? I really don't want to manually insert a page...


Can I quit my association with ONE of the Stack Exchange specific sites?

I got associated to many Stack Exchange communities and I want to clean up sites I don't use. How can I stop being associated with, for example, Mathematics Stack Exchange but not the others? I have signed up with my Google account.


infinitesimal areas and large areas scalar or vector quantities?

Is it true that an infinitesimal area is a vector quantity and large area is a scalar quantity ?


Which is a normal temperature for a laptop?

I have a Samsung series 5 my temperature is around 77-80°c when i am playing, and 48-54 on normal use it laptop don't have a month and I am not sure if it is normal.  Intel® Core™ i5-3210M CPU @ 2.50GHz × 4     8 GB of RAM     Nvidia optimus 650M (I am using Bumblebee)     Ubuntu 12.04


Pending flag indicator visible even if nothing to address

Since we got the new bar the pending flags indicator for high rep users remains even if the flags have been addressed by the user.  I am thinking if there is no action that can be taken by the user the indicator should disappear from bar.


Solving the "use of undefined type" in C++

I have an issue in my project, where I get use of undefined type AssetManager. I have been stuck with this error for 3 days now.      #pragma once #include "Components.h" #include "SDL.h" #include "Animation.h" #include "TextureManager.h" #include "AssetManager.h" #include"Game.h" #include <map> class SpriteComponent :public Component { private:     TransformComponent *transform;     SDL_Rect srcRect, destRect;     SDL_Texture *texture;     bool animated = false;     int frames = 0;     int speed = 100;      int animIndex = 0; public:     SpriteComponent() = default;     std::map<const char*, Animation>animations;     SDL_RendererFlip spriteFlip = SDL_FLIP_NONE;     SpriteComponent(std::string id, bool animate) {         setTexture(id);         Animation idle = Animation(100, 3, 0),             walk = Animation(100, 8, 1);         animations["idle"] = idle;         animations["walk"] = walk;         play("idle");         animated = animate;     }     void setTexture(std::string id) {         texture = Game::assets->getTexture(id);     } };   Here is the code of the Game.h, knowing I included AssetManager.h inside Game.cpp:   #include<SDL.h> #include<iostream> #include<SDL_image.h> #include<vector> class AssetManager; class Game {...}


In light clock thought experiment,if the observer is moving with velocity v relative to the light source&mirror frame ,then why path of light bends? According to einstein's postulate speed of light is independent of source motion??


I run a medium-sized Nagios server. It monitors roughly 40 servers with 180 services currently and is only growing by the day.  I migrated from an old Nagios setup that was configured in a very esoteric fashion, forcing me to reconfigure everything from scratch.  Now that the server is running and works for most of what we need it for, I'm looking into making it a bit more scalable; currently each hosts is its own file in /etc/nagios/hosts/, and each host has all of its services in the same file. This is obviously not optimal, but neither is obfuscating all of my configuration into hundreds of different files.  So my question is this: to any experienced Nagios admins out there, what is the best way to make use of hostgroups/servicegroups without over-complicating the configuration?


I want to convert decimal number to exact same binary number. Eg. Decimal (10) to Binary (10). Dec(10000001110000110) to binary(10000001110000110).  I am new to perl. The Lame approach I can think of is to convert dec to string and string to binary but I am sure there has to be a better way to achieve it.  I am using a function to get an array of decimal numbers.  @Arr= {111110000,110100010,...}   Note this is decimal number since when I tried to subtract 1 from it's elements I got 11110000-1=11109999.  I need it in binary format so that I can do a logical AND operation on it.  Can someone please suggest on how to achieve it.


Trigonometric Equation : $\sin 96^\circ \sin 12^\circ \sin x = \sin 18^\circ \sin 42^\circ \sin (12^\circ -x)$

Please help solving this equation:   $\sin 96^\circ \sin 12^\circ \sin x = \sin 18^\circ \sin 42^\circ \sin (12^\circ -x)$  I used numerical method to solve it and got $x=6^\circ$ but I am not able  to solve it by trigonmetry.  Thank! Best Regards, Michael.


Adding monsters to party. How to balance challenge rating.

So a party of 4 level 4 PC's got an earth elemental. Personally I use  to manage my PC's encounters. Although I don't this elemental to make the game no longer balanced when fighting battles that should be considered dangerous or difficult making them easy. In order to create this balance would the earth elemental be considered equal to 4 more PC's or equivalent level or one level 5 PC


What's the right notations for the inverse hyperbolic functions? ar_ or arc_?

To notate the inverse hyperbolic functions, we may see two different prefixes: ar_ and arc_. The former stands for AREA, while the latter for ARC. Thus, the latter seems not reasonable, since it is likely to be a sort of false analogy with the notations for the inverse trigonometric functions.  But the famous website  just use the latter. Why is it? Just "Make the Same Mistake"?


$X_1$ and $X_2$ are i.i.d random variables and the pdf of each of them is $e^{-x}$ for $x>0$ and $0$ otherwise. $Y = X_1-X_2$ and the question asks to find the pdf for $Y$? I took the approach of going from the cdf to pdf. $P(Y\le y) = P(X1-X2\le y) = P(X1\le y+X2)$. The integral boundaries would be different, depending on the sign of $y$. The integrand is $e^{-X_1-X2}$ and I did it in the order $dX_1dX_2$. In the case of $y>$0 I set the boundary for $dX_1$ from $0$ to $y+X_2$ and $0$ to $\infty$ for $dX_2$. For $y\le0$ I have $dX_1$ set from $0$ to $y+X_2$. And the boundary for $dX2$ from $-y$ to $\infty$. I tend to make mistakes when setting boundaries for these types of piecewise functions, so was wondering if I made any here? Before I proceed any further in this problem.


I want to find files in the /tmp directory. I use -path and -prune to exclude the subdirectory sgid from the results.  So I do something like this:  [root@ tmp]# find ./ -path ./sgid -prune -o -name 'foo*' ./sgid ./foo1 ./dir1/foo2 ./sgid0/foo1 ./sgid0/foo ./sgid0/foo2   However the output still contains the sgid subdirectory, which is not what I expect.  But when i do like the following：  [root@ tmp]# find ./ -path ./sgid -prune -o -name 'foo*' -print ./foo1 ./dir1/foo2 ./sgid0/foo1 ./sgid0/foo ./sgid0/foo2   The output matches my expectation. Why does the command have to include the -print option?


Problem with lstlisting in beamer... What am I doing wrong?

I am trying to to put an lstlisting environment in the left column, but I'm getting errors. Are lstlisting and the columns environment in beamer incompatible? Or is it something else?  \documentclass{beamer}  \usepackage{remreset} \usepackage{comment} % end and begin comment \usepackage{dtklogos} % for \BibTeX  \usepackage{listings} % display code on slides; don't forget [fragile] option after \begin{frame} \usepackage{bera} % pause in listing \usepackage{color} \definecolor{lightgrey}{rgb}{0.92,0.92,0.92} % defining color for listing \definecolor{darkgreen}{rgb}{0,0.6,0} % defining color for listing  \usepackage{graphicx} % importing figure  \usepackage{verbatim} % writing code   \makeatletter \@removefromreset{subsection}{section} % creates navigation circles for every slide not section \makeatother \setcounter{subsection}{1} % creates navigation circles for every slide not section  \usetheme{Frankfurt}  \lstset{language=[LaTeX]TeX, basicstyle=\small\ttfamily, texcsstyle=*\bf\color{blue}, numbers=left, breaklines=true, keywordstyle=\color{darkgreen}, commentstyle=\color{red}, otherkeywords={$}, frame=leftline, tabsize=2, backgroundcolor=\color{lightgrey}, escapeinside=|| }  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \begin{frame} \begin{columns}  \begin{column}{5cm} \begin{lstlisting}[float=*] \pause \end{lstlisting} \end{column}  \begin{column}{5cm} text \end{column}  \end{columns}  \end{frame}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \end{document} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


If an item follows normal distribution, average also follows normal distribution. What about minimum and maximum?


When users create a node, they should be redirected to a payment page; if payment is successful, the user can see the node.  Is there any way to achieve this?


How can I export just the file names of commits to a txt file in git?

I'm trying to export the file names of the files that were changed through commits in git to a txt file. How can I approach this problem? I just want the file name and I would like one file name on each line instead of all of them clumped together. Thank you in advance for the help!


Why is Nginx displaying a "502 Bad Gateway Error"?

I'm trying to create a PyPI  (Python) package repository on a Debian 8 server running Nginx 1.6.2.  I want to make all the files in a particular directory tree available for downloading to my other servers via HTTP.  My Python packages are all kept in the /var/www/packages directory:  /var/www/packages /var/www/packages/Django-1.8.4-py2.py3-none-any.whl /var/www/packages/simple /var/www/packages/simple/index.html /var/www/packages/simple/django /var/www/packages/simple/django/Django-1.8.4-py2.py3-none-any.whl -> ../../Django-1.8.4-py2.py3-none-any.whl   If I try to read my packages directory from another server using curl, I get the following error:  $ curl -I http://example.com/packages/simple/django/Django-1.8.4-py2.py3-none-any.whl $ HTTP/1.1 502 Bad Gateway   If I just try to display the Nginx default home page, I'm getting the same error:  502 Bad Gateway   The /var/log/nginx/error.log file shows this error in either case:  2019/02/06 00:53:52 [alert] 3736#0: 768 worker_connections are not enough 2019/02/06 00:53:52 [error] 3736#0: *765 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 127.0.0.1, server: example.com, request: "GET / HTTP/1.0", upstream: "http://127.0.0.1:80/", host: "example.com:80"   Here is my Nginx configuration file:  upstream pypi {   server            127.0.0.1   fail_timeout=0; }  server {   server_name       example.com;   root          /var/www/packages;    location / {     proxy_set_header    Host $host:$server_port;     proxy_set_header    X-Forwarded-Proto $scheme;     proxy_set_header    X-Real-IP $remote_addr;     proxy_pass      http://pypi;          # <- Error here   } }   As I understand it, this error means that Nginx, which is acting as a proxy, is trying to relay information from another server but has received a bad response from that server.  But in this situation, I'm merely trying to make a directory tree on the proxy server available via HTTP so, strictly speaking, there is no other server.  To troubleshoot the problem, I commented out the root directive and the entire location block.  When I did this, the 502 error went away and I could at least see the default Nginx home page. Then I began uncommenting each directive each directive in the location block, one at a time.  By doing this, I found that I could continue to see the Nginx page if I uncommented the entire location block except for the proxy_pass directive.  That proxy_pass line is what's causing the problem.  What does proxy_pass have to be set to in a situation like this?  And do I set root to /var/www/packages since that's the root directory for my packages?


Is it bad to run a processor at above 90% for long periods?

I have a Celeron N2840 in a 7yo Lenovo laptop. As a senior high school student, I need to run medium-heavy apps like MS Teams, Python and sometimes Android Studio. I've noticed that the CPU runs at about 90% constantly, while the 8Gigs of RAM have no problem. Would like to know if it is a threat when I run my laptop for about 8-10hrs straight a day, every week. The laptop has pretty much 0 cooling because of it being old.


What is a “protected” or "highly active" question?

Questions can be protected (i.e. marked "highly active").   What does it mean for a question to be protected? Why are some questions protected? Who can protect and unprotect questions? Who can answer a protected question? How are protected questions displayed? When should I protect or unprotect a question? When does the Community user protect a question?


I have this code that outputs a small family tree      \documentclass{article}     \usepackage{tikz}     \usetikzlibrary{trees}     \begin{document}     \begin{tikzpicture}[       man/.style={rectangle,draw,fill=blue!20},       woman/.style={rectangle,draw,fill=red!20,rounded corners=.8ex},       grandchild/.style={grow=down,xshift=1em,anchor=west,         edge from parent path={(\tikzparentnode.south) |- (\tikzchildnode.west)}},       first/.style={level distance=6ex},       second/.style={level distance=12ex},       third/.style={level distance=18ex},       level 1/.style={sibling distance=5em}]         % Parents         \coordinate           child[grow=left] {node[man,anchor=east]{Jim}}           child[grow=right] {node[woman,anchor=west]{Jane}}           child[grow=down,level distance=0ex]         [edge from parent fork down]         % Children and grandchildren         child{node[man] {Alfred}}         child{node[woman] {Berta}}         child {node[man] {Charles}}         child {node[woman]{Doris}};             \end{tikzpicture}     \end{document}   and what I want to do, is to write 2 lines of text in each box (e.g. Jim and underneath his DOB). How do I break a line in order to do that? \\ doesn't work.  Here is a printscreen of the output:


Showing generic class eg Table in xml comments in visual studio

I know this maybe a basic question but I just can't seem to find the answer anywhere.  I have a class like this  Table<T> {}   then I have some code that uses the above class that I would like to comment I would like to be able to do something like:  /// <summary> /// blah blah blah Table<String> /// </summary>   But I can't use the angle bracket in the comment as it thinks it's a tag and when the help shows up it just has an error about no end tag for .  How do I show generic classes in comments in Visual Studio.


I am building a beamer for a project, where i want some svg images. i have included 2 svg files and they work fine, but when i insert more they will not work.  \begin{frame}{Cooling demand}{Weight factor graph}     \begin{figure}        \centering        \includesvg[width=\linewidth,pretex=\relscale{0.6}]{AAUgraphics/Weightfactorgraf.svg}        \caption{weight factor graph for temperature gain from solar irradiation}        \label{fig:my_label}    \end{figure}  \end{frame}   this work fine for the first 2.  i use inkscape to convert into svg, and i have tried to convert into pdf_tex ass seen below:  \begin{figure} \centering \def\svgwidth{\columnwidth} \input{image.pdf_tex} \end{figure}    hope someone can help. Thanks


Tag scores are not updated and the issue is getting worse

Tag scores update is supposed to happen at 03:00 UTC every day. Tag scores are updated by a scheduled job that is time consuming and often times out  (see for example the answers for  and ).  In the past month or two, the issue with not updating the scores has gotten much worse. Tag scores are now regularly not updated for 2-3 days in a row. The job fails more often than it runs which obviously lowers usability and appeal of tag badges (which are not awarded when the script fails) and scores to some extent.  I can also guess that if a job fails on consecutive days, it only makes it harder to make it work as it has more and more tags and answers to recount.  This issue happened in the past but not to the extent it's happening now.  Please do not close it as duplicate. I'm creating a separate post as I've been asked to do it by Adam Lear in a comment for the answer for the first of the linked questions. Other posts reporting this issue have accepted answers which makes them difficult to track for the SE team.  UPDATE  I've been writing down whether the scores were updated or not every day in April.  The results are:  Day      1   2   3   4   5   6   7   8   9   10  11  12  13  14  15   Updated  -   -   -   ✓   -   ✓  -   -   -   -   -   ✓   -   -   -   Day      16  17  18  19  20  21  22  23  24  25  26  27  28  29  30 Updated  ✓   -   ✓   -   ✓   -   -   ✓  ✓   -   ✓  -   ✓   -   -   The update succeeded on 10 days, failed on 20. The situation got somewhat better in the second half of the month. Has something been done about it?


Parse question links from other SE sites

In a SE site, if you put the link to a question, the link is parsed into the question's title. For example, https://meta.stackexchange.com/questions/246034 produces .  But this does not work cross-sites.  Back at Programmers SE, I made  that contains a link to another question in StackOverflow, but as you can see, the link is not parsed.  I think it would be nice if all SE sites were parsed - even cross-sites.


Reliable cross-platform way to obtain the method time in Java

This question is not about benchmark.  I have a java thread cycle that should to operate close to a period time T:  public class MyRunnable implements Runnable {      private final long period = 10000L; //period T, in this case 10 secs      public void run() {         while() {             long startTime = this.getTime();              this.doStuff();              long endTime = this.getTime();             long executionTime = endTime - startTime;             if(executionTime < this.period) {                 long sleepTime = (this.period - executionTime);                 try {                      Thread.sleep(sleepTime);                 } catch(InterruptedException iex) {/*handle iex*/}             }         }     }      private long getTime() {         return System.currentTimeMillis();     }      private void doStuff() {/*do stuff*/}  }    Of course, depending on the schedule premption choices, Thread.sleep(sleepTime) could be slightly greater than sleepTime. But, in average, this approach provides a close averaged approximation to the period T.  The problem  The method:  private long getTime() {     return System.currentTimeMillis(); }   provides the wall clock reference time. If the machine's clock changes, forward or backwards, this implementation fails to provide a close approximation for the period T. For instance:  long t1 = getTime(); Thread.sleep(30000); long t2 = getTime(); System.out.println(t2 - t1);   prints something like 204283 if someone manually changes the clock three minutes ahead while Thread.sleep(30000) "runs".  Since the system clock is always changing (timeserver synchronization, system load, user settings, etc...) using System.currentTimeMillis() is not realiable enough for my needs.  Failed solution  In order to provide a more robust time reference I tried the following implementation for getTime method:  long getTime() {     long result;     ThreadMXBean mxBean = ManagementFactory.getThreadMXBean();     if (mxBean.isThreadCpuTimeSupported()) {         result = mxBean.getCurrentThreadCpuTime()/1000000L;     } else {         throw new RuntimeException("unsupported thread cpu time");     }     return result; }   The problem of getCurrentThreadCpuTime is that the resulting amount of time is the CPU time consumed by the Thread, not the time left at that instant. Time left when the Thread is sleeping or blocked is not taken in account. For example:  long t1 = getTime(); Thread.sleep(30000); long t2 = getTime(); System.out.println(t2 - t1);   surprising prints "0" (zero) by the getCurrentThreadCpuTime getTime's implementation.  What I want  I guess that what I need is something like this:  private long getTime() {     long cpuCycles = getAmountOfCPUCyclesSinceTheProgramStarted();     long cpuFrequency = getCPUFrequency();     long result = cpuCycles / cpuFrequency;     return result; }   The problem is that I didn't found a java way to implement getAmountOfCPUCyclesSinceTheProgramStarted() and getCPUFrequency() in a cross platform fashion.  Finally, my question is: how to obtain the spent time of a method in java in a reliable and cross-platform way?


I created a set of Views based blocks which will be displayed in the Dashboard's Main Content Region.But those all of them are not for the site admins. Some of them are for other roles. So I have configured those blocks' visibility settings. Added those specific roles to the "Show block for specific roles" tab. But the problem is those are being displayed in the admin dashboard as well but with no content, actually it says "empty".   Is there any way to get rid of this?   A possible duplicate but no answers in that post as well.


Getting redirected when I try to go to the quant Stack Exchange site

Someone recommended that I post my question on quant.stachexchange.com. Whenever I try to go to that site (I am not sure if the Stack Exchange site exists) I get redirected to something asking if I am a robot, then www.clickvalidator.net. Does this seem right? It seems like something weird is going on with DNS.  I was typing quant.stackexhange.com. Different URL, same problem.


16G memory or an SSD to upgrade a Macbook?

I'm deciding on whether to spend the money to upgrade my RAM or add an SSD to my Macbook Pro.  Here's the stats...   Early 2011 MacBookPro8,1 i7 2.7Ghz 8G RAM STBD1000400 Seagate Hybrid 1TB drive   I could spend about $130 on either...   16G RAM 250G Samsung EVO 850 SSD (replacing the DVD drive)   The machine is mostly used for coding, compiling, web browsing, watching movies and listening to music.  It is rarely CPU bound.  The OS and applications and home directories should fit easily into 250 gigs with my media going onto the 1TB drive.  Thoughts?


Result fail when minus two number has parseDouble from EditText in java, android

I have two EditTexts:  <EditText     android:id="@+id/edit_text_1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="0.35" />  <EditText     android:id="@+id/edit_text_2"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="0.3" />   and I parseDouble these EditTexts:  EditText e1 = (EditText) findViewById(R.id.edit_text_1); EditText e2 = (EditText) findViewById(R.id.edit_text_2);  double a1 = Double.parseDouble(e1.getText().toString()) double a2 = Double.parseDouble(e2.getText().toString()); Log.e("a1", a1 + ""); Log.e("a2", a2 + ""); Log.e("Result", (a1 - a2) + "");   0.35 - 0.3 = 0.05 but the result is:  12-06 13:14:00.816 11557-11557/com.example.android.test E/a1: 0.35 12-06 13:14:00.816 11557-11557/com.example.android.test E/a2: 0.3 12-06 13:14:00.816 11557-11557/com.example.android.test E/Result: 0.04999999999999999   Why is this happening?


Trouble understanding Alternating Current (AC)

How does alternating current get anywhere if it travels "back and forth" in the wire?. I understand that Direct Current is a flow of electrons through a wire, but I have always been confused with how Alternating Current works. I expect I am missing something simple but could anyone point me to a resource that does a good job of explaining AC, or perhaps offer an explanation themselves? Thanks!


How to resolve the error in java : Exception in thread "main" java.lang.NullPointerException in an online compiler

I have written a simple code to read a 2d integer array of size n1 and n2 and print the middle element in java. import java.io.*; import java.lang.*; import java.util.*; public class Main {     public static void main(String args[])throws IOException {         BufferedReader br=new BufferedReader(new InputStreamReader(System.in));         int n1=Integer.parseInt(br.readLine());         int n2=Integer.parseInt(br.readLine());         int[][] arr=new int[n1][n2];         System.out.println("n1"+n1+"n2="+n2);         String[] sarr=new String[n2];         for(int i=0;i<n1;i++) {             sarr = br.readLine().split(" ");//line 13             for (int j = 0; j < n2; j++)                 arr[i][j] = Integer.parseInt(sarr[j]);         }         System.out.println(arr[n1/2][n2/2]);     } }  I was getting the below error in an online compiler but when executed in intellijIDEA there was no error. Exception in thread "main" java.lang.NullPointerException     at Main.main(Main.java:13)


Here is what I have done so far: $$I=\int \frac{dx}{\sqrt{x^2+16}} =\frac{1}{4}\int\sqrt{\frac{1}{\left(\frac{x}{4} \right)^2+1}}\,dx$$ $\frac{x}{4}=\tan(u), dx=4\sec^2(u)$ $$\therefore I=\int\sqrt{\frac{1}{\tan^2(u)+1}}\sec^2(u)\,du=\int\sec^3(u)\,du$$ now by integration by parts: $$I=\tan(u)\sec(u)-\int\tan^2(u)\sec(u)\,du$$ I am sure $\int\sec^3(u)du$ is a standard integral but I am now sure if IBP is the best way to go. Is there another obvious way of doing it?


Recent news events in the US have resulted in many headlines about "nude photos of young women" and variations.   Obviously it's the women who are nude, not the photos, so why does this phrasing persist? Is it an idiom, or does it just flow better, or is it some other nuance of usage that I haven't seen in other situations?  Edit: I don't think the linked question is directly on point (though I do see the connection), nor do I think just saying "nude photos are photos of nudes, duh" is an informative answer or comment. Defining nude photos as photos of nudes ignores the fact that the headline refers to photos of women.


Please stop disrespecting my wishes by logging me in where I've explicitly logged out

The recent changes to the  system are disrespecting my explicit wishes. I am in the habit of logging out of some SE communities when I am done. In the case of one community I am actively heeding , spending as little time there as possible and much of that logged out. In the scheme of things it really doesn't matter what my motivation for logging out is though. When I log out of a community it is a positive action on my part, I have to find the "log out" link, follow it and then confirm that I want to be logged out. I am explicitly saying that I do not wish to be logged in to this community. Having done this, if I return to the community I do not expect or want to be logged in automatically and against my express wishes. The recent changes the global authentication system do exactly this. I understand from Anna's post  We are going to recognize you in some ways on sites where you don't have a profile. This is still a work in progress, but most notably you will see "join this community" in the top bar instead of "sign up" and "log in".  Please extend this to recognise that I have a profile with this community but am logged out and offer me the opportunity to "log in to this community" rather than forcing me to do so.


What use when I don't know the gender of a person?

When I don't know if a person is male or female, what word shall I use? I don't know but in spanish we use the male form: he. PD: I know that I could say He/She but I don't want.


Does Python have class prototypes (or forward declarations)?

I have a series of Python classes in a file. Some classes reference others.  My code is something like this:  class A():     pass  class B():     c = C()  class C():     pass   Trying to run that, I get NameError: name 'C' is not defined. Fair enough, but is there any way to make it work, or do I have to manually re-order my classes to accommodate? In C++, I can create a class prototype. Does Python have an equivalent?  (I'm actually playing with Django models, but I tried not complicate matters).


In Philosopher's Stone, Hagrid says that "there's not a single witch or wizard who went bad who wasn't in Slytherin," and yet Sirius Black, a Gryffindor, was still considered to be one of the most dangerous and evil wizards alive at that time. How did the community at large explain Sirius's being a Gryffindor while he was still believed to be a faithful follower of Voldemort? Might they think the Sorting Hat makes mistakes?


I made a loaf of bread and scored the top with a razor to regulate its expansion as it baked. However, it had its own ideas and pretty much ignored mine, as below:   Why? And how can I produce a more beautiful loaf next time?


How do I install Ubuntu 14.04.02 alongside Windows 8.1?

Where can I find the how-to guide to install Ubuntu 14.04.02 alongside Windows 8.1? Because I don't know anything about it. I have a brand new system with a Core i5 processor.


Prove that,  $$\binom{3n}{r}=\binom{3n-1}{r} + \binom{3n-1}{r-1}$$  Here is my solution below, this is my first time working through a pascal identity problem and I just wanted to see if this made sense:  By the definition $\binom{n}{r}$ we have,  $$\binom{3n-1}{r-1}=\frac{(3n-1)!}{(3n-1-(r-1))!(r-1)!} = \frac{(3n-1)!}{(3n-r)!(r-1)!}$$  and,  $$\binom{3n-1}{r}=\frac{(3n-1)!}{(3n-1-r)!r!}$$  Thus, starting with the right hand side of the equation,  $$\binom{3n-1}{r-1} + \binom{3n-1}{r} = \frac{(3n-1)!}{(3n-r)!(r-1)!} + \frac{(3n-1)!}{(3n-1-r)!r!} \\ = \frac{(3n-1)!r}{(3n-r)r!} + \frac{(3n-1)!(3n-r)}{(3n-r)!r!} \\ = \frac{(3n-1)!(r+3n-r)}{(3n-r)!r!} \\ = \frac{3n!}{(3n-r)!r!} \\ = \binom{3n}{r}$$ \


Similar matrix of $M\in\mathcal{M}_2(\mathbb{C})$,

Let $M\in\mathcal{M}_2(\mathbb{C})$, Show that $M$ is similar with a matrix having one of the following forms: $$ \begin{pmatrix} z_1 & 0 \\ 0 & z_2 \end{pmatrix} ~,~\text{with }(z_1,z_2)\in\mathbb{C}^2\qquad \begin{pmatrix} z & 1 \\ 0 & z  \end{pmatrix} ~,~\text{with }z\in\mathbb{C} $$ An idea please


What does "Legacy USB Mouse" support in a BIOS mean?

What does a "Legacy USB Mouse" option in a BIOS mean?  Yes legacy usually means older revision, or obsolete. So legacy usb mouse means support for "old style usb mouses".     That's not really answering the question. As Mr. Tamm, my high school electricity teacher, liked to say, "Yes, and oranges taste orangey."   What does legacy USB mouse support mean?   What is a legacy USB mouse?  There's an "old style" USB mouse?  What changed between what version of usb and what version of usb that made mice incompatible? Why was the change made?  When was the change made? Who made the change? What was the virtue of the "new USB mouses" over the "old USB mouses"?   Put it another way:     What is the BIOS doing when "Legacy USB Mouse" option is enabled?   What is the BIOS doing when "Legacy USB Mouse" option is disabled?   See also


A favorite view of Spider-Man (at least in movies and games) is of the hero web-slinging his way through the streets of New York City. But what becomes of all the web ropes that Spider-Man discards as he moves from building to building? We don't see them hanging around the city, so presumably someone removes them.  Do people collect them as souvenirs? Does Spider-Man come back later to clean up after himself? Does the city employ a group of cleaners just to remove the webs?


I am a Canadian with a Tier-5 Visa that starts on December 30th, 2020. I'm moving with my girlfriend, she goes to school in the UK. I currently have no job lined up, but this might change. I was hoping to arrive earlier than my start date, ideally 2-weeks, in order to deal with the 2-weeks quarantine, then search for a place the rent, and spend Christmas there. Is it likely that a) I get turned away before I get on the plane, b) I am not let into the UK, c) I would have to leave and re-enter the country on my start date, d) It'll be fine? Also, what happens if my Biometric Residence Permit is not ready?


I am a relatively newer Python developer, but I come from a Java background. In Java, there is one-line Boolean checker/assigner (for lack of a better term):  int result = (x)?y:z;   I am trying to use a similar approach in Python, but I am not sure whether this structure exists. Is there a way to declare a variable, check whether a condition is true and assign it to one of two values without using if/else?


Showing there is no ring whose additive group is isomorphic to $\mathbb{Q}/\mathbb{Z}$

Show that there is no commutative ring with the identity whose additive group is isomorphic to $\mathbb{Q}/\mathbb{Z}$.


Let $f$ be a differentiable function with $|f'(x)|\leq1$ and $f(-3)=-3, f(3)=3$. Then find $f(0)$.   I think this is mean value theorem problem. But I can't solve... help me please.


How to force copy default for drag-n-drop to a folder on Windows 7?

As , on Windows 7 machines, by default, when you drag a file to another folder on the same drive, it moves the file there.  This can be overridden by holding down the control key on the keyboard before releasing the file, to force a copy.  Similarly, holding down the shift key forces move behavior.  Only for select folders, I would like to change the default to be copy instead of move.  I was thinking I might be able to share the folder and then mount it as a shared folder from myself to trick the OS into defaulting to copy as the shared folder appears to be non-local storage.  Is there a way to configure a specific folder on Windows 7 to default to copy instead of move for local files being dragged to the folder without doing this convoluted solution of sharing a folder with myself?  Can I add a registry entry that overrides this behavior for a specific directory?


Conjugacy Class in a matrix group with columns of standard basis

I want to find the conjugacy classes of this group: $$G=\{(a_1,a_2,a_3):a_i=\pm e_j\}\subset GL_3(\mathbb C)$$ I know that $S_3$ is one of the subgroups of this group, so I can check which elements of $S_3$ continues to be conjugate in our group, I know that in $Z(G)$ there is two elements $I,-I$. I know that I have to check the diagonal matrices on which ones are conjugate, but I don't know how to finish and find the others conjugacy class of this group, and I don't Know how to find the number of the elements of the conjugacy class. I'll be thankful for help


Desktop distro with installer image less than 700MB?

Previously I'm using Lubuntu because the installer can be burnt in CD.  Now the 16.04 x64 installer image size more than 700MB. Plus, it feel too heavy on my computer.  I'm now using Bodhi Linux but looking for several more choice.


$\{a_n\}$ be a sequence such that $ a_{n+1}^2-2a_na_{n+1}-a_n=0$, then $\sum_1^{\infty}\frac{a_n}{3^n}$ lies in...

Let $\{a_n\}$ be a sequence of positive real numbers such that   $a_1 =1,\ \  a_{n+1}^2-2a_na_{n+1}-a_n=0, \ \ \forall n\geq 1$.   Then the sum of the series $\sum_1^{\infty}\frac{a_n}{3^n}$ lies in...  (A) $(1,2]$, (B) $(2,3]$, (C) $(3,4]$, (D)$(4,5]$.   Solution attempt:   Firstly, we figure out what $\frac{a_{n+1}}{a_n}$ is going to look like. We get, from the recursive formula, $\frac{a_{n+1}}{a_n}=1+\sqrt{1+\frac{1}{a_n^2}}$ (remembering the fact that $a_n>0$, the other root is rejected).   We know that, if $\lim_{n \to \infty}\frac{a_{n+1}}{a_n}>1$, then $\lim a_n \to \infty$.   Further, $(a_{n+1}-a_n)= \sqrt{a_n(a_n+1)}>0$. (Again, the other root is rejected due to the same reason).   Hence, $(a_n)$ increases monotonically.   Therefore, the largest value of $\frac{a_{n+1}}{a_n}$ is approximately $1+\sqrt{1+\frac{1}{1}} \approx 2.15$  Now, the sum can be approximated as $\displaystyle\frac{\frac{1}{3}}{1-\frac{2.15}{3}} \approx 1.3$ (In actuality, $\mathbb{sum}< 1.3$).  So, option $(A)$ is the correct answer.   Is the procedure correct?   I have been noticing a handful of this type of questions (based on approximations) lately, and the goal is to find out where the sum / the limit of the sequence might lie.   Is there any "definitive" approach that exploits the recursive formula and gives us the value, or does the approach varies from problem to problem?


Why would you use a supertype variable to refer to a subtype object?

What is defferent between  List<Integer> list = new LinkedList<Integer>();   and   LinkedList<Integer> list = new LinkedList<Integer>();   When to use the first one and when to use the second one?


Are the genres "co-op" and "multiplayer" different?

I had an argument with a Steam friend, and the conversation was about the topic of so-called "multiplayer" games.  I brought up games like TF2, Dota2, and SR3 as games that define what multiplayer is.  My friend, however disagreed, and insisted that co-op and multiplayer are different categories; co-op, where you play along players, and multiplayer, meaning playing against someone else.  Am I wrong to think these are two seperate genres of games? Or are co-op and multiplayer virtually the same?


The avatar on my posts is hiding from me!

So I just noticed that the avatar on all my posts looks like this:    ... but only for myself. Other people still see my actual avatar. I also see the correct avatar in chat.  How can I entice my avatar to come out of hiding?


I just saw this insect collecting polen from bougainvillea blossoms on the Greek island of Skyros, in the Aegean sea. For future reference, this is in the middle of August and the sighting was at around 17:00.           I posted all 4 photos I took since the rude little thing didn't have the decency to sit still to let me get a clear shot. I'd say it was about 2cm long, certainly no more than 3.


Is there a tool or something which can quickly enable or disable ClearType without going through the windows 7 ClearType-configuration dialog every time?  I need this because I have to make screenshots quite often and screenshots look blurred when ClearType is activated. And when ClearType is disabled everything looks blurred on my screen, so I usually enable it again after taking a screenshot.


I've ran out of chocolate bars and didn't realize I could enchant my giant spoon and knight's armor. Is there any way to get more reliably?


Should trending questions be auto-protected?

I noticed today that a request for protection came up due to the the large number of me-too answers on a trending question I answered recently.  This got me thinking, since trending questions get far more attention than the average question, should questions that trend be automatically protected?  On the upside, this does seem to be a common problem and the auto-protection could be put in place only while the question is trending.  On the downside, it would make it more difficult for new people to participate in answering a trending (highly visible) question so it could be a barrier to entry.  Thoughts?


Preposition usage in “at/in the corner of the room”

He is sitting at/in the corner of the room.  Which preposition is more appropriate in this example?


How do I split the values in Python list at regular intervals?

Here's a list like this.  mylist = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]   I want to split this list every 4 intervals.  In other words, I want to make it like this.       [1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]   I want to divide the list and save it.  Is there a function that provides this partitioning capability?


Georeference option not visible in QGIS 3.0 for French version

I am using QGIS 3.0 Girona Early Adopter Release. I used to use Raster-->Georeference--> ... to georeference images in QGIS 2.18 but now I can only see the interactive georeferencing option in my version. Where did it go?  Could it be because my version is the French release?    When I go to the plugins and search for georef, I don't have the option for georeferencer GDAL only freehand raster georeferencer is available.  I have the experimental plugins option ticked too.


Best way to connect to MySQL with PHP securely

I want some input on what you guys think is the most secure way to connect to a MySQL database using PHP. Currently the way I'm doing it is a utility PHP file that I include in the top of all my other PHP files. The utility PHP file is this:  <?php     if(!defined('IN_PHP')){         die("hackerssss");     }     $mysql_host = "localhost";     $mysql_user = "root";     $mysql_pass = "root";     $mysql_db = cokertrading; ?>   Any suggestions?