sorry fresh user. I installed about 9 days ago and had issues with Unity disappearing which took 5 days of headaches to fix. It never did fix, I reinstalled.   I set up Plex (media server) and while the server is running and can be accessed by external network devices, I can't add files. Plex says this is because of permissions. I have gone up and down the forums here and at Plex to get an answer. It seems everyone says   chmod -R 755 /media/My\ Book/Videos   will change permissions to allow the folder "Videos" on my external USB 2.0 NTFS 3TB Western Digital drive (which is mounted and accessible through the file manager) as well as every sub-directory and file contained therein to be accessible to user "Plex".  I have used file manager and as soon as you click to change permissions it changes right back. When I chmod with -c it tells me every file is changed (usually 600) to 755 as I commanded it to do. I did   ls -l   to verify and there is no change. (I also used ls -l to make sure I knew who the owner was and it is me (mvl1014). ls -al gives me the same info.)  I swear to god I tried to sudo it and after smashing my head against this keyboard for basically the entirety of my day, I tried it as root. I was scared shi-less but couldn't come up with anything else. sudo su to root and then chmod -R -c /media/My\ Book/Videos  Same result. -c told me every single file was changed and a check in Unity or in terminal confirmed not a darn thing changed.  Now it seems to me that even if that isn't the thing stopping Plex from working there is still a problem with this command not going through.  12.04LTS -- on gen 1 i7 (2.7 GHz I believe) with 6 GB ram   I've attempted to attach a screenshot but I'm told I need 10 reps to do so, which means I'm copy/pasting too.  Please excuse my obfuscation, but Lorem Ipsum seemed unnecessary. And I tried multiple ways to format this but it looks perfect every way and messed up each time in the preview below. (Ugh, I'm a mess.)  $ chmod -R -c 755 /media/My\ Book/Videos  .....  .....  .....  mode of `/media/My Book/Videos/xxxx/xxxx/xxxx.mkv' changed from 0600 (rw-------) to 0755 (rwxr-xr-x)    ls -al shows:  mvl1014@FX6800:/media/My Book/Videos$ ls -al   total 88  drwx------ 1 mvl1014 mvl1014     0 Aug 28 15:17 .   drwx------ 1 mvl1014 mvl1014 20480 Sep  3 14:29 ..  drwx------ 1 mvl1014 mvl1014  8192 Aug 28 15:18 xxxx drwx------ 1 mvl1014 mvl1014 49152 Aug 16 14:02 xxxx drwx------ 1 mvl1014 mvl1014  8192 Aug 27 21:36 xxxx drwx------ 1 mvl1014 mvl1014  4096 Jul 23 19:09 xxxx   I apologize if this has been asked. I looked through this place plus at all the suggested "Similar Questions". The closet thing I got to an answer , but running the provided code with my own UID didn't work either.


I am in my late 20s, living in the UK, and in my third year of professional work (one year industrial placement, two years since graduating from University). I have very little in the way of monthly expenditure at the moment- living in a house share (with very cheap rent), most bills included in rent, and have pretty much reached the limits on which the various bank accounts I have open will pay interest.  Since graduating, I have been saving using a few different current accounts which pay interest on balances up to a certain limit (a few of which have conditions that you have a number of Direct Debits going out from those accounts in order to receive interest on the balance of the account).  But since I am now at the point where I am earning interest on the maximum balance for most of these accounts, I am starting to look at other ways to save/ invest, but I'm just not really sure what to look into/ what the best options to explore are.  I have already opened: Santander 123 account, Bank of Scotland Classic Account with Vantage, TSB Classic Plus account and a Club Lloyds account, as well as having an ISA and one or two Regular Savers on-going. I am maintaining the maximum balance that you can receive interest on in each of these current accounts. My ISA matured recently (3 years paying 3.75%), and that balance is now sat in a Flexible ISA (earning 0.8%) while I explore what's best to do with it.  I take home roughly 1k per month after tax, rent and other regular outgoings such as food, travel, leisure, student loan repayments, phone/ broadband, etc.  I am at the point financially where I have saved enough to have a reasonable deposit on a house, but am not at the point in life where I want to commit to being a home-owner for a couple of reasons:    My work is contract based, so there's no guarantee that I will be working in the same location as I am at the moment, this time next year (in fact that's looking less and less likely, as the current contract is coming to an end, and there's some uncertainty as to when the client will begin the next contract- government projects). It would not be unrealistic to think that I may be in the situation where I don't have any work at all in a few months time, and so I am currently applying for other jobs. Having gone through the usual cycle of school- university- job, etc... I am thinking that now would potentially be a good time to look into doing some travelling, so I would rather not pursue buying a house for the moment, in case I do decide to do some travelling for a year or so.   I have recently started watching the stock prices of a few companies to get an idea of investing in the stock market, but feel like I need to research this & watch the values for a while before I go ahead and invest in any shares.  I have a credit card, which I pay off monthly, but other than that, the only debt I have is my student loan (approximately £25,000).  So, given my situation, are there any other ways that I can save/ invest that I am not currently doing? Or would it be best to start using any excess funds, that I won't earn any interest on, to pay off my student loan quicker? The interest that my student loan is incurring is currently 0.9%.


How can I change (remove) a Seahorse password

I installed Ubuntu 12.10 and entered a password in SeaHorse. I would like to remove the password of "Default" but I get this error :  GDBus.Error:org.freedesktop.Secret.Error.NoSuchObject: The collection does not exist   Is there a fix or a way to bypass modify the password ?


I want to make an interface so that I can control my python methods I have already made. So I am trying to make a pop-up of an operation I made (see code below). But I get an error in the last line where I test to call it: RuntimeError:  Operator 'MESH_OT_generate_mold' does not have register enabled, incorrect invoke function  import bpy  class GENERATEMOLD_OT_template(bpy.types.Operator):     """Generate Mold"""     bl_idname = "mesh.generate_mold"     bl_label = "Generate Mold"      z_height: bpy.props.FloatProperty(name = "Z height: ")      #@classmethod     #def poll(cls, context):     #    return context.active_object is not None      def execute(self, context):                  self.z_height = 3         bpy.ops.mesh.primitive_cylinder_add(vertices = 32, radius = 1, depth = self.z_height)                          return {'FINISHED'}      def invoke(self, context, event):         return context.window_manager.invoke_props_popup(self, event)   def register():     bpy.utils.register_class(GENERATEMOLD_OT_template)   def unregister():     bpy.utils.unregister_class(GENERATEMOLD_OT_template)   if __name__ == "__main__":     register()      # test call     bpy.ops.mesh.generate_mold('INVOKE_DEFAULT')  The name "MESH_OT_generate_mold" is not something I called it. Any ideas what's wrong?


I've made today the greatest error on my server using root user:  chown -R 33:33 /   instead of chown -R 33:33 . within some webroot folder.  Well, this brought ssh down. I made it this far to get it working again, so far apache, mysql and php are still working, but I don't know if I ever restart them, or if the server will fail upon restarting.  Is there any "index" or package which will enable reverting these permission to the right / previous ones?  Here is the console output which help me realize and abort that operation:    Can I do anything to recover?


I have used tracert command to check local network status, at the second hop I get random- high numbers for latency,(attached file), but when I use ping the total latency has an average of 1ms.  What is the problem? I really appreciate your help.  BR.


Half life of radioactive elements: are there some atoms in a different state than others?

I think I generally understand what half-life means. What I wonder is, in a large collection of atoms of a radioactive element, are some atoms more likely to decay than others due to internal state or is it completely random? If the former, can an atom be examined to determine if it is more likely to decay than some other atom?


Use Pair as a key in a LinkedHashMap (Java)

I have a HashMap like this  LinkedHashMap<K, V> = new LinkedHashMap<>();   this map is used as cache to implement LRU (least recently used) In this cache I want to save results from functions that have no "side-effect" so for the same input they will always produce the same output. Im also using Bi-Functions that have <T,U,R> T and U are generic types. Here comes the Pair<T,U> into play. How do I save a Pair like this as a key into my Hash-Map? And can someone explain how exactly the overwriting of the equals(Obj o) and hashCode() function is supposed to help with this problem?


To calculcate tension in a rotating ring (about its own axis) the usual approach is to consider an element of angle $d\theta$ and consider the tension forces acting on it but isn't an element of circle taken to be a straight line? But in that case the tension forces would cancel out and the ring wouln't be able to rotate. So are we taking elements such that forces do not cancel? That seems to be a biased approach to me.


What are the differences between malloc(3posix) and malloc(3)?

They need the same header file and the signatures are same.**But their descriptions are different indeed.**What are the differences between malloc(3posix) and malloc(2)?If i see malloc is called in a source code, how can know which one is called indeed?  As per the linux programmer's manual, which says:     MALLOC(3POSIX)                                                 POSIX Programmer's Manual   MALLOC(3POSIX)      PROLOG          This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the   corresponding          Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.      NAME          malloc — a memory allocator      SYNOPSIS          #include < stdlib.h >     void *malloc(size_t size);       DESCRIPTION          The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements   described here and          the ISO C standard is unintentional. This volume of POSIX.1‐2008 defers to the ISO C standard.           The malloc() function shall allocate unused space for an object whose size in bytes is specified by size and whose value is   unspecified.           The  order  and contiguity of storage allocated by successive calls to malloc() is unspecified. The pointer returned if the   allocation succeeds          shall be suitably aligned so that it may be assigned to a pointer to any type of object and then used to access such an  object    in  the  space          allocated (until the space is explicitly freed or reallocated). Each such allocation shall yield a pointer to an object disjoint from   any other          object. The pointer returned points to the start (lowest byte address) of the allocated space. If the space cannot be allocated, a   null pointer          shall  be  returned. If the size of the space requested is 0, the behavior is implementation-defined: the value returned shall be   either a null          pointer or a unique pointer.   and     MALLOC(3)                                                      Linux Programmer's Manual   MALLOC(3)      NAME          malloc, free, calloc, realloc - allocate and free dynamic memory      SYNOPSIS          #include < stdlib.h >     void *malloc(size_t size);       DESCRIPTION          The  malloc()  function allocates size bytes and returns a pointer to the allocated memory.  The memory is not initialized.  If   size is 0, then          malloc() returns either NULL, or a unique pointer value that can later be successfully passed to free().


Can I travel within US if I have an H3 Visa?

I have an H3 visa (Trainee visa) which allows me to enter the US for a specific amount of time.I am not a US citizen nor do I possess any state ID's, I will be in training in our Head Quarters in California.   My question is, am I allowed to fly domestically to other states with my foreign passport and a valid H3 visa?


So the question I was trying to solve is   "Print the first 4 letters of name on new line [name = 'Hiroto']"  I got a solution, but I was wondering if there was a way to do the same problem using index values to make it work with any name I used.   name = "Hiroto"  new_name = " "  for letter in name:     if letter != "t":         new_name = new_name + letter     if letter == "t":         print(new_name)


From my question before :  Since I updated third party modules at ConTeXT, i get problem can't use modules at My ConTeXt document and I always get a message like this :     Before I can use modules, I know this question equal my question before  How to fix my problem at ConTeXt ?


How to be 100% certain a USB drive has not been tampered with and has no malware?

Say you find a usb drive on the street and you want to be 100% sure it hasn't been tampered with, neither via software nor by modifying its hardware (adding or modifying components, etc.), so that there is zero risk of malware.  Is fully formatting it enough to be 100% certain no malware remains? If so, is fully formatting it with the standard slow process from within Disk Utility in Tails 3.2 enough to do so?  Asume the highest possible technical ability from the attacker. Not just reasonable or plausible scenarios.


I'm drawing the following cylinder which represents a water flowing and cooling down  \documentclass[a4paper,10pt]{article} \usepackage{pstricks} \usepackage{auto-pst-pdf} \usepackage{pst-solides3d} \usepackage{xcolor} \usepackage{epstopdf} \usepackage[english]{babel} %change language if necessary \usepackage[english,verbose]{layout}%change language if necessary  \begin{document}  \begin{pspicture}(-3,-4)(3,4)  \psset{viewpoint=50 50 20 rtp2xyz,Decran=50,lightsrc=viewpoint  }   \psset{color1=cyan,color2=red}   \psSolid[h=8,r=0.5, object=cylindre, ngrid=50 15, RotZ=30, hue =1 0 0 0 0 1,linewidth=0.01pt ](0,0,-2.5)  \end{pspicture}  \end{document}   I would like the black lines to disappear, or atleast partially merge with the image. Is there anyway to perform this ?


Why solid angle of a closed surface from exterior is zero?

Actually my question comes from Gauss law which says charges outside a closed surface, doesn't effect on the whole electric flux of the surface.  The reason of that is that the solid angle of a closed surface while measuring it from outside of the surface, is zero. ( on the other hand, the solid angle of a closed surface from inside the closed surface is $4\pi$)  My question is why solid angle of a closed surface from exterior  is zero? Please don't use Stokes' theorem!


Could not find required OpenGL entry point 'glGetError'

I am not able to play "Half-Life-2" on Steam + Ubuntu 14.04 . Error shown in message box on screen:      Could not find required OpenGL entry pint 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated.   I have a Dell Inspiron Laptop.  My OS is Ubuntu 14.04 and my graphics card is AMD Radeon HD 8600M.  I have installed AMD properietry Driver.    The partial output of "glxinfo" is as follows:      name of display: :0     libGL: screen 0 does not appear to be DRI3 capable     libGL: pci id for fd 4: 8086:0a16, driver i965     libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/i965_dri.so     libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/i965_dri.so     libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory.     libGL error: failed to load driver: i965     libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/swrast_dri.so     libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/swrast_dri.so     libGL: driver does not expose __driDriverGetExtensions_swrast(): /usr/lib/i386- linux-gnu/dri/swrast_dri.so: undefined symbol: __driDriverGetExtensions_swrast     libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory.     libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory.     libGL error: failed to load driver: swrast     display: :0  screen: 0     direct rendering: No (If you want to find out why, try setting LIBGL_DEBUG=verbose)


These are the  important assumptions we need to verify before conducting the actual regression analysis? How do we carry out the Data inspections for #3, #4, #6?  Assumptions:  1. a continuous dependent and an independent variable. 2. Linear relationship between the two var 3. independence observations 4. homoscedascity must exist 5. no significant outliers 6. residuals (errors) of the regression line are approximately normally distributed. 7. there is independence of observations.


Event Viewer: Event ID 2 'Session "Circular Kernel Context Logger" failed to start with the following error: 0xC0000035'

I've had 40 of these errors in the last 7 days.  Can anyone give an explanation of the error and what I might do to correct it?  I'm running Windows 7 Ultimate 64 bit.  As a possibly important aside I'm runnning a copy of Windows 7 that I've yet to activate (still trying to find the damn code before I cough up dough for the new one.)


What to do if I can't trust my advisor no more?

After so many incidents happen that my advisor trying to bad mouthing to my committee, sobstege my publication, secretly removing me from my PhD projects I feel I cannot trust my advisor anymore. Now, I feel everything he said was insincere and full of lie. My advisor always says positive thing but all end up negative. He is not consistent of what he said and what he actually does which disgust me. I don't want to let him handle my manuscript or assign me project because I always fear that he will do something underhanded. If I really grant a PhD from my advisor, I would be ashamed of such lineage. All I want now is live in bubble space undisturbed focusing on my own topics. I want to be myself as a phd student and one day as a professor. What should I do? Please help!


How to downgrade iPhone 4S from iOS 9.0.1 to iOS 7.1.2?

(Please read the whole question before flaming me)  Today I updated my iPhone 4S (Model A1387) to iOS 9.0.1 from 8.4. Since the Wifi doesn't work with either of these versions I decided to downgrade the software to iOS 7.1.2.   After I downloaded myself a  for the iPhone 4S and tried to [Shift]+Update my phone in iTunes I received the . After a quick web search I booted the iPhone into  and tried it again. After that I tried adapting my hosts file in Windows as showed on . This also didn't work. I also tried downloading the    -File from different providers and also tried to use a third party tool called . Then I found out, that recovery mode is not enough and I .  Since the  I was sure that it will work this time, since the DFU mode seems to be some kind of , but after hours of effort I'm still stuck with iOS 9 and nothing has worked out to bring me back to iOS 7.1.2.  So as the title states: How can I downgrade my iPhone 4S to iOS 7.1.2? (As I am going to jailbreak this device afterwards, you can also show a direct way to load a jailbreaked firmware)


"That don't make your place safe" grammer

Strangely, in Amy Winehouse' song "In my bed" there's a line in the chorus which goes:     So sorry if I turn my head Yours is a familiar face But that don't   make your place safe   Obviously, "that" is like "it" and should be followed by "doesn't".  Is this a bold grammatical mistake? some extremely regional British* way to conjugate verbs? or maybe simply a style thing, to give the song more "colloquial" feeling"?     *although the song itself is sung with an American accent.


I have not managed to evaluate the integral. I feel the idea is just split the integral into a sum of integrals $$\int \frac{1}{x(x+1)...(x+n)}dx = \int \left(\frac{A_1}{x} + \frac{A_2}{x+1} +... +\frac{A_n}{x+n} \right) dx$$ So, technically, the main problem is to determine the coefficients in the numerators of these fractions. Hhm, it has occurred to me that I might bypass the system of $n$ equations just putting $x = 0$, $x = - 1$,..., $x = - n$ after multipling the whole expression by $x(x+1)...(x+n)$. The idea can be of help to solve the risen problem. Another idea is just to decompose the fraction by representing the numerator of the initial fraction, which is 1, as an expression considered to be suitable to attain the objective. For example, $$ 1 = x + 1 - (x + 2) + (x + 3) - (x + 4) +... $$ I might attempt to adopt the idea but there is a nice trick that solves the problem? I came across the integral when searching for the competition problems on integration. When trying to apply "brutal force" method, I got many brackets and equations afterwards. Hence, there must be more cunning technique.


Long stay Schengen visa requirement for spouse of UK citizen

I am an Australian Citizen travelling with my wife (with dual passport Australian and UK) to the Schengen area. We will be travelling together in a camping car and intend driving around various countries for approximately 4 months. Then returning to the UK before returning to Australia. Do I require an extended stay Schengen visa or am I covered, as I will be travelling with my wife on her UK passport? How and where would I a apply for the appropriate visa?


Will my Borderlands 2 campaign be ruined if I play matchmaking?

In Borderlands 1 I needed help on a boss, so I tried to find some people to help me in matchmaking. When I found the game I needed, I connected but they were playing something else so I exited. But when I got to my single player campaign, my story skipped through half the game! I'm so afraid that if I do matchmaking in Borderlands 2, my single-player will be ruined! Can you help me?


How to answer "Have you ever been refused a visa?" if I've had a refusal overturned

A few years ago, I applied for a UK visa. The visa was initially refused and I had no rights of appeal. However, the refusal letter had some glaring mistakes and I sent an email to the Embassy. The refusal was "overturned" by an ECM.  I am now making an application for a visa which has the question "Have you ever been refused a visa?". How should I answer it?


How to call a partition of $X$ which consists of all singleton subsets of $X$?

In other words, if $X$ is a set, then how do we call $Y=\{\{x\}:x\in X\}$?  $\{X\}$ is already named the trivial partition, so that cannot be it. Complete partition and total partition did not yield enough search results. Does it maybe not have a name?  A related question: does $Y$ exist for every $X$?


Boundary of product manifolds such as $S^2 \times \mathbb R$

Simple question but I am confused.  What is the boundary of $S^2\times\mathbb{R}$? Is it just $S^2$?  What would be the general way to evaluate the boundary of a product manifold?  Thanks for the replies!


Flying to Canada via London / Toronto from Mumbai: Do I require a transit visa?

I am planning to travel to Canada (Ottawa) from Mumbai. I have Canada immigrant visa (Permanent Residence). I haven't yet received the PR card, and my port of entry is Ottawa.  I have two options, 1. Travel to Ottawa via Toronto 2. Travel to Ottawa via London  I want to know whether I would require a transit visa for for 1st option? Because, I already have a Canadian immigrant visa!  Also, will I require a transit UK visa, if I select option 2? I checked the below website of UK govt.     Here it says the following exemption,     Exemptions      You don’t need a visa if you have one of the following:      a visa for Canada, New Zealand, Australia or the USA (this can be used   for travel to any country)   I believe in my case I don't require a transit visa. Can anyone confirm please?


How to automatically install entire Google Web Fonts collection?

I'm basically looking for an unattended way to deploy/install the  collection into several Ubuntu boxes. I've searched for PPAs, packages or user scripts but without much luck.  Any advice will be much appreciated. Thanks a lot in advance!


How to install Git GUI on my local machine that runs on Ubuntu 12.04 LTS 64-bit OS?

I'm running Ubuntu 12.04 LTS 64-bit OS on my local machine. I want to setup/install Git GUI on this machine. Then I'm having one repository at GitLab that I need to make clone of on my machine, then I should be able to do normal git operations like pull, push, commit, etc. with Git GUI.  Can someone please provide me step by step instructions from installing this Git GUI on my machine to execute normal Git operations?  Thanks in advance.


Find smallest $\sigma$-algebra that contains all singletons

Find smallest $\sigma$-algebra so that it contains sets $\{x\}$, where $x \in \mathbb{R}$.  I was thinking of putting  $ F = \{ A\subset \mathbb{R} : A \text{ is countable or } A^{c}  \text{ is countable}\} $, but while I was proving it, I figured out that maybe that isn't it.


Should I go back to do conventional logistic regression after LASSO logistic regression?

I used to use simple (multivariable) logistic regression plus stepwise regression to select important predictive variables. Though, I saw many critics on this method. Thus, I plan to use LASSO and check whether it gives similar results compared to the stepwise regression.  I am primarily using the glmnet package from R.  After the cv.glmnet, I got the lambda.min and lambda.1se respectively. I am still fine at this point that I probably should choose the lambda.1se for the lambda.   Please comment on above workflow as I wonder whether I have any misunderstandings.  The main question is: I get the coefficients corresponding to lambda.1se by coef(cvfit, s = "lambda.1se"). How should I interpret these coefficients? I acknowledged that some of the unimportant variables have been dropped, thus only important variables are kept.  Should I put these selected (important) variables back into the conventional logistic regression? It is because, I am studying epidemiology, which I am interested in whether these variables are independently associated with the outcome. I am not sure whether I can deduce similar conclusion statement from LASSO's output. Can we get the OR with 95% CI for each coefficient?  Thanks!


Getting error with this code but I can't figure it out  trigger LeadConvert on Lead (after insert) {     list leadsToConvert = new list();      Database.LeadConvert lc;     string convertedStatus = '';     list convertStatusList = new list();     convertStatusList = [Select Id, MasterLabel                          from LeadStatus where IsConverted=true limit 1];     if(convertStatusList.size() > 0){         convertedStatus = convertStatusList[0].MasterLabel;         }     else{              convertedStatus = 'Closed - Converted';          }      for(Lead l : trigger.New){         if(l.AutoConvert__c == true){             lc = new database.LeadConvert();             lc.setLeadId(l.ID);             lc.setDoNotCreateOpportunity(true);              lc.setConvertedStatus(convertedStatus);             leadsToConvert.add(lc);         }     }      list lcrList = new list();     lcrList = Database.convertLead(leadsToConvert); }


Can anyone help me by providing a sample python-script to modify the size of anyone feature in this Blender model 3D model of Humanoid

I have a project deadline and I want to change the scaling of this humanoid model using a python script only, I want to select the specific bones of the "metarig" object and increase or decrease its scaling by setting values in the script for its length or width. I am totally new to Blender that is why I am asking for a sample script, rest i shall modify the script for other bones in the rig, so if anyone can write a script and show me  how we can select and modify scaling for one bone, that would be of great help. You can find the blender object here,


How can I calculate the current carrying capacity of a DC copper bus bar with respect to temperature?  Bus bar specifications: Width=40mm Thickness=6mm


I have Ubuntu 16.10 right now and I need to update it to something that is still supported. So I tried following this guide:   but running the commands in the updating from 16.10 section don't work. They give errors about the repository not being updated. Could anyone give me a way to update to a supported version? I don't care too much which one, it's just that 16.10 isn't supported anymore.   Here are the error messages I get when I run sudo apt update && sudo apt dist-upgrade  > Err:8 security.ubuntu dot com/ ubuntu yakkety-security Release        > 404  Not Found [IP: 91.189.88.161 80] Ign:9 > https:/ /dl.google.com/linux/chrome/deb stable InRelease                > Get:10 http : // repository.spotify . com stable InRelease [3,302 B]        > Hit:11 https:/ /dl.google . com/linux/chrome/deb stable Release           > Ign:12 http:/ /ppa.launchpad . net/texlive-backports/ppa/ubuntu yakkety > InRelease Err:13 http: / /archive.ubuntu.com/ubuntu yakkety Release      > 404  Not Found [IP: 91.189.88.152 80] Err:14 > http:/ /archive.ubuntu.com/ubuntu yakkety-updates Release               > 404  Not Found [IP: 91.189.88.152 80] Hit:15 > http://ppa.launchpad . net/umang/indicator-stickynotes/ubuntu yakkety > InRelease Err:10 http://repository . spotify . com stable InRelease        > The following signatures couldn't be verified because the public key > is not available: NO_PUBKEY EFDC8610341D9410 Err:16 > http://ppa.launchpad . net/texlive-backports/ppa/ubuntu yakkety Release  > 404  Not Found Reading package lists... Done                       E: > The repository 'http://security . ubuntu . com/ubuntu yakkety-security > Release' does no longer have a Release file. N: Updating from such a > repository can't be done securely, and is therefore disabled by > default. N: See apt-secure(8) manpage for repository creation and user > configuration details. E: The repository > 'http://archive . ubuntu . com/ubuntu yakkety Release' does no longer have > a Release file. N: Updating from such a repository can't be done > securely, and is therefore disabled by default. N: See apt-secure(8) > manpage for repository creation and user configuration details. E: The > repository 'http : //archive.ubuntu . com/ubuntu yakkety-updates Release' > does no longer have a Release file. N: Updating from such a repository > can't be done securely, and is therefore disabled by default. N: See > apt-secure(8) manpage for repository creation and user configuration > details. W: An error occurred during the signature verification. The > repository is not updated and the previous index files will be used. > GPG error: http://repository . spotify . com stable InRelease: The > following signatures couldn't be verified because the public key is > not available: NO_PUBKEY EFDC8610341D9410 E: The repository > 'http://ppa.launchpad . net/texlive-backports/ppa/ubuntu yakkety > Release' does not have a Release file. N: Updating from such a > repository can't be done securely, and is therefore disabled by > default. N: See apt-secure(8) manpage for repository creation and user > configuration details.   The next command works without any errors. I had to mess up some of the links because otherwise it wouldn't let me post it.


Dell LAtitude E6430 with CPU Intel® Core™ i5-3210M, 64 bits, no longer boots after updating 14.04 LTS system to kernel 3.13.0-66. It hangs off after completion of the password. Back to the 3.13.0-64 kernel works, but still with a system error, pending since about the beginning of the year (beginning approximately for the kernel 3.13.0-40) and never corrected by subsequent upgrades. It seems that the system 14.04 LTS is going worse and worse on this computer. Is there a solution ?


Convergence of the sequence $\left\{x_n\right\}$ where $x_n = \frac{1}{1.3}+\frac{1}{2.5}+...\frac{1}{n(2n+1)}$

Let $\left\{x_n\right\}$ be a sequence where $x_n = \frac{1}{1\cdot3}+\frac{1}{2\cdot5}+...\frac{1}{n\cdot(2n+1)}$   I have to calculate, to which point does the sequence $\left\{x_n\right\}$ converge, using Euler's constant($\gamma$). That is, I have to use the fact that the sequence $\left\{\gamma_n\right\}$ converges to $\gamma$, where $\gamma_n =1+\frac{1}{2}+...+\frac{1}{n}-\log n$.  But I cannot reduce $x_n$ to any form relating $\gamma_n$. Please help me solve it. Thanks in advance.


How can I save an exception so it can be passed as an object to a function?

I am trying to unit test a function whose parameter is an exception. However, it seems that because the function only throws the exception and doesn't return in, I can't just feed a function and parameter that would throw an exception.  How can I deal with this?


I was making a scene in blender and I wanted to change the texture from "Material_1" to "Material_2". It lets me change it but when I go to rendered view the part looks the same. can someone please help me


When post a question the side bar's position is not fixed while scrolling the page

When post a question ("Ask Question") the side bar's position is not fixed while scrolling the page. There are some extra spaces are displaying in the top.  GIF for the same:    Update: This issue occurs in the  page too when scrolling the page.


Proof that every circle has the ratio of $\pi$

We know that the ratio between the circumference's length and diameter is equal to $\pi$, but can this be proved for every circle? Or is this an axiom?


A switch that is only ON if the reference voltage is matched -+ 0.1 volts

Im a beginnerish will electronic and im looking for a switch that is only ON if the reference voltage is matched -+ 0.25 volts. So if i have a reference of 2.7v to match and i feed the switch a 2.75v the switch would be ON. But if i feed it  2.5v or 2.85v the switch would is OFF.   This might be a simple google search, but i am lacking the correct terminology.


i'm a noob. Please fix my line to get yellow output in terminal. print('https://%s' % encoded_uri.decode('utf-8') + temp)  Thanks.


t-test what needs to be normally distributed?

I'm aware that the t-test needs 'normally distributed data'.   But take the variable y. When it is plotted without being split by group, it isn't normally distributed:  set.seed(1) y <- c(rnorm(1000, 1), rnorm(1000, 5)) group <- c(rep("A", 1000), rep("B", 1000)) df <- data.frame(y=y, group=group) library(ggplot2) ggplot(df, aes(y)) + geom_histogram()     But when y is split by group, it is normally distributed:  ggplot(df, aes(y)) + geom_histogram() + facet_grid(~group)     Can anyone clarify if a variable only needs to be normally distributed after being split by group?


How to stop VideoLAN to switch to VideoLAN window when in playlist

I am using VideoLAN on Windows to play a list of videos (Ctrl + L) in the background - I am only interested in listening the sounds of those videos. But VideoLAN will switch to the VideoLAN window everytime it plays a new video in the playlist. And that is really annoying because I need it to play videos in background so I can keep doing what I am working at (editing text files, writing a blog etc). Is it possible to stop VideoLAN to switch to the VideoLAN window?


Added user supplementary group, but 'groups(1)' not showing change

I'm trying to add myself to the fuse user group but it doesn't look like the change is taking effect even though /etc/group looks correct after invoking addgroup or usermod.  I've tried both ...  sudo addgroup fjohnson fuse   and   sudo usermod -a -G fuse fjohnson   /etc/group shows the change  fuse:x:104:fjohnson   but I can't read   -rw-r----- 1 root fuse 215 Oct 16 10:39 /etc/fuse.conf   as   cat: /etc/fuse.conf: Permission denied   and groups(1) returns   fjohnson adm dialout cdrom plugdev lpadmin admin sambashare


How deep should posts be set for an 8 foot privacy fence?

I am planning to build an 8 foot fence and will use galvanized post due to high moisture in the area. Looking for some advice regarding the depth of the post. These are 10 foot post so I was planning to place them 2- 2 1/2 feet deep and secure with up to 100 pounds of concrete mix. The post will be 6 feet apart and I will use 2x4x12 stringers. Due to the lumber shortage I will have to use 1x6x8 PT pine pickets instead of cypress. There is 125 feet to build. Any ideas on the depth to place the posts? Thanks


you should make your bed after you wake up (or say: after you woke up)? A dilemma in expressing the idea

Ok, A should say:   you should make your bed after you wake up.   or   you should make your bed after you woke up.   In case 1, the waking-up action happened before "make the bed", but English doesn't have "past in the future" tense though we do have "future in the past" tense (was going to do....)  In case 2, you broke the universe because the "waking up" action did not exist at the time of saying.


How to make a div appear on a screen all the time, even when there is no content present in it

I want to make a standard frame with two divs side by side.    .test {   width: 100%;   height: 100%; }  .test22 {   width: 100px;   background-color: #000;   border: 1px solid #000;   height: 1000px; }

     Here is a JSFiddle:   Now as you can see with a fixed height on 2nd div I'm able to see the container with black bgcolor on the screen. But I cannot have a fixed height as the content is variable and hence I changed: height:100%  instead of fixed height.  When I do that, I don't see anything on the screen, except the border I added  JSFiddle:   If I add some content in it, it'll start showing up:  JSFiddle:   but I want to be able to see the black container always whether I have content or not with height: 100%?  Is this possible?


solution of differential equation $\left(\frac{dy}{dx}\right)^2-x\frac{dy}{dx}+y=0$

The solution of differential equation $\displaystyle \left(\frac{dy}{dx}\right)^2-x\frac{dy}{dx}+y=0$   $\bf{My\; Try::}$ Let $\displaystyle \frac{dy}{dx} = t\;,$ Then Diferential equation convert into $t^2-xt+y=0$  So Its solution is given by $\displaystyle t=\frac{x\pm \sqrt{x^2-4y}}{2}$  So we get $$\frac{dy}{dx} = \frac{x\pm \sqrt{x^2-4y}}{2}$$  Now How can I solve after that, Help me  Thanks


Why most particle accelerators used vacuum diodes instead of transistors?

HERMES III (High Energy Radiaton Megavolt Electron Source) at the Sandia at Sandia National Laboratories is the world's most powerful gamma ray generator. HERMES-III produces a highly energetic beam that tests the capability of electronics to survive a burst of radiation that approximates the output of a nuclear weapon. It used a field emission diode, instead of a transistor. I wonder why most accelerators used vacuum diodes instead of transistors. Transistors are much smaller. What are the reasons?


How to do less damage than instant damage effect with command blocks?

So no one knows how to deal damage without instant damage effect, but how can I use it but deal less damage? Instant damage 1 is still way too much damage so how do I use command blocks to do less?


How to back up & restore a rooted phone?

Before handing in my OnePlus 6T for repair, I want to create a full system backup and reset the phone to factory defaults. Afterwards, I want to restore the original state. My phone is rooted with Magisk. How do I do a full system backup? Note that this is different from a backup as part of migration to a new phone or a partial backup as part of fixing software issues.


How many interpretations are there of the acquisition of the Death Star Plans in Legends?

Disney recently showed the trailer for their Star Wars spinoff Rogue One with the canonical interpretation of the Death Star plan acquisition.  This made me think about how often this event (codename “”) has been portrayed in Star Wars “Legends,” and how varied the portrayals are. However, many of them seem to have one thing in common: , a stormtrooper turned Rebel turned Jedi.  If we assume that the “Legends” storylines where Kyle Katarn acquired the plans in person (so not through hiring someone else) are different portrayals of the same interpretation, how many interpretations are there of the acquisition of the Death Star plans by the Rebel Alliance?


Proving $\displaystyle \sum_{cyc}\frac{(a^2+b^2)}{a+b}\leqslant \frac{3(a^2+b^2+c^2)}{a+b+c}$

For $a,b,c>0$, prove $\displaystyle \sum_{cyc}\frac{(a^2+b^2)}{a+b}\leqslant \frac{3(a^2+b^2+c^2)}{a+b+c}$ I've simplified the inequality by multiplying both sides with $(a+b+c).$ So the inequality became $\displaystyle a^2+b^2+c^2\geqslant \sum\limits_{cyc}a\frac{(b^2+c^2)}{b+c}$ From here I ve tried use some well known inequalities like Cauchy-Schwarz or QM-AM-GM-HM but as I m not very fluent with these yet I couldn't finish the proof.


So we purchased a brand new home in June 2016 and found the builder put a heat vent under the dishwasher. He explained it's pretty normal but after asking HVAC pro's, it isn't.   My question is, should I have a toe kick vent installed? The builder didn't even cut the floor opening for it, but it is installed under the house.


Filemanager that asks for sudo rights when it needs it

On my Mac I can copy files using the Finder, and if the destination folder has a different owner, a window pops up and asks for credentials.   On Ubuntu or Linux Mint I don't see anything like that. Then I need to start Nautilus or Nemo from the commandline using sudo rights. I would like to get a popup whenever it is needed.   So I use Nemo (or Nautilus) just like normal and do whatever I need to do. I close it and open it another time, and at one point or another I need to copy a folder to /opt. Then it refuses because /opt is owned by root. A window pops up and asks for my sudo password or for a user that has sudo rights if the specific user has no sudo rights. The folder is copied to /opt and that's it.   Is is possible to let it work like this, with an extension or something? Do other filemanagers have this option?


Difference in the number of count when count is static and non static in Java

I am trying this below program  class Car1 {     static int count;     Car1()     {         System.out.println("Car instance has been created...");     }      Car1(int arg) {         System.out.println("Car instance has been created...");     }      Car1(double arg) {         System.out.println("Car instance has been created...");     }     Car1(int arg1, double arg2) {         System.out.println("Car instance has been crreated...");     }     {         count++;     } } public class MainClass10 {     public static void main(String[] args) {         System.out.println("Program Started");         new Car1(11);         new Car1(11, 12.11);         for (int i = 0; i<9; i++)         {             new Car1();         }         Car1 c1 = new Car1(11.12);         System.out.println("Total number of cars: " + c1.count);         System.out.println("Program Ended");     } }   The output for number of count is 12 and when I try this by changing count variable as non static then 'number of count is 1'.  Could anyone please help me understand this?


How to see if a mod is compatible with other mod(Minecraft)

Please tell me all the files I need to open,find and/or edit in order to check this.


Xubuntu's Network Manager cannot detect wifi on Lenovo G450 laptop

I just recently installed Xubuntu 14.04 on dual boot in my Lenovo G450 laptop. For some reason, I can only connect to the internet on an ethernet cable since the Network Manager fails to detect any wifi signal, be it mine or the neighbors'. The service providers for my wifi and the neighbors are the same, so they should have WPA2-PSK. The laptop can connect to wifi just fine when I boot into Windows 7.  I've been searching for solutions on the Net, but most of them seem situational and I'm not sure which is applicable. I'm also completely new to Ubuntu and have only been practicing very basic commands on the terminal for the last few days, so I also don't want to mess around with solutions that may end up doing more harm than good due to misapplication.


When I run the shower, mostly hot water, the pressure will run normal for a minute, then raise for a minute, then repeat. My home is supplied by a well. What is causing this?


How do transitional forms survive without the full adaptation?

This may be an odd question, but this is one thing I've always wondered. How does a dragonfly ancestor with early structures that will one day become wings gain any benefit from these useless limbs that don't work?  It seems in an intermediary context like this, that the adaptation would almost fall under a category more along the lines of something vestigial--something defunct.  I understand the creature adapts with no understanding or control of the process, and it takes extremely long periods of time to see any significant changes from one anatomy to another, but it would seem that statistically that would work against the animal, not for it. It's not like the dragonfly goes from the land and water to having fancy new fully operational wings.  The longer a species is stuck with an unhelpful adaptation, the longer they would be exposed and at a disadvantage. There is one way in which I could see this happening, and that is a prolonged series of random mutation in favor a winged route for the insect with no real input from their environment.  We all know that mutation and variation drift (all of which are relatively random) are part of the evolutionary process, but it is often described in more concrete terms, and the creatures in between an ancestor and a descendant have been discovered and described, but often not very well to the public.  The mutant albino bear ancestor being better suited for arctic stealth and eventually becoming the polar bear and diverging from the brown bear is an example given in the new Cosmos that actually could happen overnight. The bear is born with the full adaptation.  Even if the bear weren't instantly white, fur slowly becoming lighter leading to better hiding capability, or having a thicker coat to help it keep warm makes more sense than the precursor to an entire limb like wings or a tail though.  I suppose that it's possible to say the that random mutation is the primary method of evolution, and the apparent improbability of plants and animals surviving with incomplete, underdeveloped adaptations can be answered by realizing that the plants and animals alive today are the cousins of countless species that actually weren't helped by the wings, and some of that is random too.  And with that in mind, it's slightly more obvious, but I'm wondering if there's more to it or something I'm overlooking.  I've struggled to find any discussion about this topic in the literature, which I may have simply missed because it often goes over my head. I'm hoping my conclusion is helpful.


When I plug in earphones or HDMI, I have to manually change the speaker settings

Whenever I plug in my earphones or HDMI cord, the speaker settings don't automatically change to output from them. I have to go into the sound settings and manually choose them and then do a speaker test before the will work. I just want it to automatically switch to them if I plug them in. I am using 14.04.


Using grep to search texts with single quote?

I am using gedit text editor with embedded terminal in ubuntu 12.04. I'm trying to search for some text using grep. I want to search for this line of code   'type' => 'select'   I tried:  grep -r '\'type\' => \'select\''  But grep didn't return any results.  So can someone kindly tell me how to search for the code above?


When do we use 'on the web' and when 'in the web'?       Roombeats provides image content marketing solutions by linking images to product or brand information and distributing it on the web.


Cannot access Ubuntu samba shares from Mac OS after install of Ubuntu 14.10

Just installed Ubuntu 14.10 on my server, replacing 14.04 (not upgrading it). I gave it the same name (ubuntu-server) as before. I installed Samba and redefined the shares previously established, using the same names: sde, sdf, etc.  However, I can no longer access those shares from Mac OS (Yosemite). I've rebooted the server and the Mac OS systems, to no avail. The server and the shares appear on both of the Macs, but my connection to the server is that of Guest, and although I've enabled Guest access, when I try to access one of the shares, I get a dialog "The operation can't be completed because the original item for "" can't be found". If I try to change the connection to be as a registered user, I get "There was a problem connecting to the server "". Check the server name or ip address and then try again . . .".  Does anyone know what the problem is or what I can check to get further details about what the actual problem is?  Regards, David


Is it okay to submit bug reports and feedback here about the iOS app, even though it's not being developed?

It seems that every iOS app feedback submission here is met with a reminder that the Stack Exchange iOS app isn't currently being worked on. Is it okay to make submissions here about the app anyway, assuming that the app will one day be revisited and the feedback might be useful?


I am new to latex, and saw a lot of other questions asking about this, but I could not find a way to fit my 5 column table in a page. \begin{table}[h] \centering \begin{tabularx}{\textwidth}{|c|c|c|c|c|}     \hline     Area of Interest & Pearson Correlation and p-value & Spearman correlation and p-value & Mean squared error (MSE) & $R^2$ Value\\     \hline     Buoy 44097 and satellite $H_s$ (0.25 dd) & (0.9872, 0.05$<$)  & (0.9663, 0.05$<$) & 0.1268 & 0.9683\\     \hline     Buoy 44097 and satellite $H_s$ (0.25- 0.5 dd) & (0.9795, 0.05$<$)  & (0.9641, 0.05$<$) & 0.1605 & 0.9586\\     \hline \end{tabularx} \caption{Correlation, $R^2$ Value, and MSE values between buoy 44097 and Saral/AltiKa Hs measurements.} \end{table}  I got this:


Are there any textbooks/works on Graphic Design that are objectively seen as the best?

I'm looking to read a textbook or a work about graphic design or typography that is considered to be essential or the best for its field, and in particular, I would like one that is somewhat old and has stood the test of time.  It could be either technicalities of design or philosophy of design or something else, but it needs to teach concepts that can be applied timelessly; If the book covers the ins and outs of Adobe Photoshop or Illustrator and how to use the software, that isn't helpful to me.  I would like a book that teaches a way of thinking that can be applied no matter what the software or hardware used, as a good designer needs only their mind to produce a piece of art.  An example of what I'm looking for is a book from the field of programming: SICP. This is an ideal example as it has withstood decades of use and is still relevant today because it teaches concepts rather than the nitty-gritty details of the language used.    This is not a subjective question, I am asking for a specific type of book and not your favourite book. Any recommendations would preferably be written by a reputable graphic designer, professor, or have been used in a college course.  Thanks!


A fair 6-sided die is rolled 6 times, what's the probability the outcome has exactly 2 or 3 elements?

A fair $6$-sided die is rolled $6$ times independently. For any outcome, this is the set of numbers that showed up at least once in the different rolls. For example, the outcome is $(2,3,3,3,5,5)$, the element set is $\{2,3,5\}$. What is the probability the element set has exactly $2$ elements? how about $3$ elements?   I know the sample space is $6^6$. The counting for $2$ elements is $6C2 \cdot 6!$? I would really appreciate the help! :)


Let $G_1, G_2$ be subgroups of a group $G$ and $G_1G_2 = \{g_1g_2: g_1 \in G_1, g_2 \in G_2\}$. Prove that $|G_1| \cdot |G_2| = |G_1G_2| \cdot |G_1 \cap G_2|$.  I've thought about cosets and considered sets $g_1G_2$ for all $g_1 \in G_1$. Sum of all these sets is equal to $G_1G_2$ and each element is counted the same number of times, $|G_1 \cap G_2|$ presumably, but I can't seem to prove this fact nor see a connection.


Is there a hypothesis test for B1 > B2 in multiple regression?

Is there a way to calculate a p-value for the hypothesis that population coefficient regression coefficient $B_1$ is larger than that of $B_2$ when doing multiple regression on a sample group?  In the test I'm trying to perform $x_1$ and $x_2$ are both binary, but I'm interested in the general case as well.


how to return multiple variations of function in python

How can I write the following code so that not all functions are the same?  >>> def g(x): ...     l = [] ...     for i in range(1,10): ...         def f(x): ...             return x + i ...         l.append(f) ...     return l   The idea should be that g returns a list of 9 functions where the first function returns x+1 the second x+2 etc. However, since in python everything is an object all previous function definition will be overwritten. How can I solve this?


prove that all the roots of  $\sum_{k=0}^{n}\frac{z^{k}}{k!}$ are in $\{z:\frac{n}{e}<|z|<2n\}$. I thought about using Rouché's theorem but there is no function which I can compare to. Does anyone have an idea?


I am learning how to write a package by looking at code from existing packages. A nice one on GitHub () uses a lot of  \newcommand definitions which contain the @ character (e.g. \bk@BW , \bk@doublestate etc.). Is this just a style of writing \newcommand or does the @ character have special significance?


Please add TeX rendering on the Android app

MathJax isn't currently working on the Android app, which makes it totally useless for the 'technical' sites like  or .  For example, in the Android app:    Same post in a (mobile) browser:     Please add this functionality!


Sorry that the question title is unclear, I didn't know how to ask it.  Take set $A \subseteq [0,1]$, measurable. Does there exist a sequence $x_1,x_2,\dots$ such that $\forall x_i$,   \begin{align*} \displaystyle\frac{\mu\left([x_i,x_{i+1}]\cap A \right)}{\mu\left([x_i,x_{i+1}]\right)} \in \{0,1\} \end{align*}  where $\mu$ is the Lebesgue measure?


From today onwards StackOVerflow is having the new toolbar. I have a question about it.  In Old toolbar it shows the 10K Moderator Tools (Remaining Flagged post count, Remaining suggested edit count etc).    But in new toolbar it's not present:    Where is those moderator tools ? Where can I get those in new tool bar ?


Even though that is probably not necessary (as answered in ), I updated the US address where I will be staying for my second stay in the US after the ESTA application. Now, there also is a field for a US contact person, where I had listed the hotel of my first stay, but using the "update" option of the official ESTA application page, there does not seem any way to update this. Should I take any additional steps to update this information as well?


Linear independence between vectors and subvector spaces

I have got the following task:  Let U, U' be linear subvector spaces of a K -vector space V with U ∩ U' (by 0 is meant the null space containing only the null vector). Prove the following statement: if v_1,....,v_r ∈ U and w_1,...., w_s ∈ U' form two linearly independent systems, then the vectors v_1,....,v_r, w_1,...., w_s ∈ V are also linearly independent.  Could someone help me please with this task, please? I do not understand how to proceed. Thanks for helping me.


Count distinct values of a field in a file

I have a file contains around million number of lines. In the lines I have a field called transactionid, which has repetitive values. What I need to do is to count them distinctly.  No matter of how many times a value is repeated, it should be counted only once.


Can you help me with my capacity planning?

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


What do you call those high areas that give you a full view of the city?

A place where you could sit and see something like this (with a fall if you step further):    (Not looking for a technical term, just a common one).


Let $f:M\to N$ be a function. For all $Y$ subset of $N$, $f(f^{-1}(Y))$ is a subset of $Y$.  When $f$ is surjective, $f(f^{-1}(Y))$ equals $Y$. Is this true or false?  I guess because of $f(f^{-1}(Y)) = \mathrm{id}(Y)$ this statement is true. Can give some one a better explanation?


How to stop LaTex numbering equations within section

\documentclass[]{phstyle} \usepackage{latexsym,amsfonts,amssymb, undertilde} \usepackage[fleqn]{amsmath} \usepackage{makeidx}  %Preamble  \numberwithin{equation}{chapter} %\renewcommand{\theequation}{\thesection.\arabic{equation}}  \begin{document}  %\include{chapI}   these 2 lines are because the chapters are different tex files  %\include{chap1}  \renewcommand{\thechapter}{\Roman{chapter}}  %\setcounter{chapter}{0} %\renewcommand{\theequation}{\thechapter.\arabic{equation}}  \chapter{Introduction}  \section{Chap I Section1}  \begin{equation} this is equation I.1 \end{equation}  \begin{equation} this is equation I.2 \end{equation}  \section{Chap I Section2}  \begin{equation} this is equation I.3 \end{equation}  \chapter{Chapter 1}  \section{Chap 1 Section 1}  \begin{equation} this is equation 1.1.1 \end{equation}  \begin{equation} this is equation 1.1.2 \end{equation}  \end{document}     I have been typing Chapters 1-5 that contain sections and subsections and equations. The equations were numbered globally, i.e. if I had 3 equations in section 1 of Chap 1, they were numbered 1.1.1, 1.1.2, 1.1.3 and for Section 2, the equations were 1.2.4, 1.2.5, etc.  Recently I had to change Chap 1 and everything in it to Chapter I (roman number) and Chap 2 were renumbered to Chap 1, etc.  My problem is that LaTeX started numbering the equations in Chap I (the other chapters did not have this problem) according to the sections and not globally anymore. That is, the 3 equations in Chap I were I.1, I.2, I.3, and the equations in the second section of Chap I became I.1, I.2, etc instead of I.4, I.5, etc  I needed the prefix to be the chapter and not the sections. I don't understand why there is a change. I have never used \numberwithin in my book  Here are some of my codes  \documentclass[]{phstyle} \usepackage{latexsym,amsfonts,amssymb, undertilde} \usepackage[fleqn]{amsmath}   for the equation numbering in Chap I  \renewcommand{\thechapter}{\Roman{chapter}} \renewcommand{\theequation}{\thechapter.\arabic{equation}} **   Previously when Chap I was Chap 1, ** was  \renewcommand{\theequation}{\thesection.\arabic{equation}}   I have also tried the line below but it didn't work  \renewcommand{\theequation}{I.\arabic{equation}}   Thank you in advance


I am developing the backend for a website. I always had the trouble of making an attractive design for my websites and have never hired any graphic designer yet. I have no logo nor web template.  What are the steps to hire a graphic designer? What information should I read about before hiring one in order to make most out of our time? Where should I find him? What questions should I ask him? How much do they charge and what qualifications should I look out for? Should I disclose my business ideas to the designer or could that be risky?


How did Rutherford conclude that most of the mass (as well as the positive charge) was concentrated in the nucleus?

Geiger and Marsden's experiment led Rutherford to believe that the positive charge and most of the mass of the atom was concentrated in a small region. I understand what led him to conclude the way the positive charge is positioned in the atom. But how did he conclude that most of the mass was in a small region (the nucleus)?  How did the distribution of the mass matter after all? Given that the electric force is greater than the gravitational force by many magnitudes, the force between the positice charge and the electrons was predominantly electric.   So how did Rutherford conclude that most of the mass is in the nucleus?


I accidentally ran chmod 777 * (without the -R parameter) on my home directory.   Will It be a problem? Then how to solve it?


How to force biblatex to show question mark when there is a missing citation?

I have the opposite of the usual problem: I want to get back the question marks for missing citations! With bibtex, when there is a key that does not match any entry, in the generate pdf file there is a "?" instead of the citation. Biblatex instead puts the \cite  command's argument in bold face when the argument isn't found in the bibliography. Is there any way that I can get the question mark behavior with biblatex? I just find it easier to identify my possible mistakes or automate a sanity check with a simple search for question marks. Also with some citation styles, this biblatex behavior is recipe for disaster. edit: For the sake of completeness, I use biber as the back-end. Also, I know I can check the log or ask biber to do some validations. Still I prefer the question marks.


Why did the Stack Overflow blog switch back to WordPress from Jekyll?

Why did the Stack Overflow blog switch back to WordPress from Jekyll again? It was originally on WordPress, then switched to Jekyll for some time, and now it's been switched back.  This screenshot from Developer Tools shows that it's now on WordPress:    And this login page:    Did Jekyll fail to scale well, or is there some other reason to switch back to WordPress?


I have a feeling the answer to this is going to be "not possible", but I'll give it a shot... I am in the unenviable position of modifying a legacy VB6 app with some enhancements.  Converting to a smarter language isn't an option. The app relies on a large collection of user defined types to move data around.  I would like to define a common function that can take a reference to any of these types and extract the data contained. In pseudo code, here's what I'm looking for:  Public Sub PrintUDT ( vData As Variant )   for each vDataMember in vData     print vDataMember.Name & ": " & vDataMember.value    next vDataMember  End Sub   It seems like this info needs to be available to COM somewhere...  Any VB6 gurus out there care to take a shot?  Thanks,  Dan


Why is there a strong distinction between stream and block ciphers?

If I don't err, in the literature a stream cipher is one in which each plaintext bit is processed individually, commonly via xor-ing with one bit of a random or pseudo-random bit stream, while a block cipher (in ECB mode, i.e. ignoring the add-on processing operations like CBC etc.) operates on n bits at a time with operations that are the same for a given key, i.e. each successive groups of n bits are processed in exactly the same manner.  If one looks at the corresponding literatures, one finds in the first case mostly works on linear or non-linear feedback shift registers and in the second case ideas of design of a rather different genre. That could justify the differentiation in terminolgy however IMHO only on the assumption that no cipher designs could lie inbetween the two categories. But that assumption seems to me to be an invalid one. Anyway, let's consider the classical ciphers. Is a Vigenere cipher or a (additive) cipher with a running key a stream cipher or a block cipher? That question seems not to be very satisfactorily to be answered, I am afraid.


'Devon Police is' or 'Devon Police are'—should 'police' be treated as singular or plural?

Which of the following is correct?        Devon Police is recording incidents       or        Devon Police are recording incidents


How do I avoid checking for updates for a specific module?

In a current project I have had to patch the life out of a few modules (node hierarchy, workbench access and a few more). These modules are now absolutely perfect for the project's needs and are very unlikely to break with future updates to core.  That being said, when the app is handed over the clients will have full (user 1) access to the system and will therefore be warned when these modules have available updates. And they will update them, no matter how many times I beg them not to (oh how easy life would be without clients!).  Is there a way (perhaps in the modules' .info files) to persuade the update manager not to check for updates for these modules?  EDIT  I'm aware of the project status url key that's available for the .info file so I guess I could set that to a non-existent URL but I'd much rather do this in a clean way if possible.


No implicit conversion between int and null

I have a class and it has nullable properties like below;  public class Sample {    public int? ID { get; set; }    public string SampleName { get; set; }    public bool? Active { get; set; }    public DateTime? Date { get; set; } }   When i try to do something like below;  foreach (DataRow tableItem in table.Rows) {         Sample sample = new Sample()         {             ID = tableItem["ID"] != DBNull.Value ? Convert.ToInt32(tableItem["ID"].ToString()) : null,             SampleName = tableItem["SampleName"] != DBNull.Value ? tableItem["SampleName"].ToString() : null,             Active = tableItem["Active"] != DBNull.Value ? Convert.ToBoolean(tableItem["Active"].ToString()) : null,             Date = tableItem["Date"] != DBNull.Value ? Convert.ToDateTime(tableItem["Date"].ToString()) : null,         };      data.Add(sample); }   It gives error like "Type of conditional expression cannot be determined because there is no implicit conversion between 'int' and ''".


For some of my physics questions I need to evaluate $\int_{0}^{\frac{\pi}{2}}\cos^n\theta\,d\theta$ and  $\int_{0}^{\frac{\pi}{2}}\sin^n\theta \,d\theta$  I know the direct formula for $\int_{0}^{\frac{\pi}{2}}\sin^n\theta \,d\theta\;$ which is $(\frac{n-1}{n}*\frac{n-3}{n-3}*......\frac{1}{2})*\frac{\pi}{2}$ My question is what should I do if n is odd and What is the similar formula for $\int_{0}^{\frac{\pi}{2}}\cos^n\theta\, d\theta$ ?  and some light on how these formulas can be found in internet like 'name of the topic'. Because, all I am finding are how these can be done by integration by parts which I don't want.


Can someone help me finish installing Ubuntu on my partitioned hard drive?

I currently have windows 8.1 and I had someone partition it for me and let me to download the newest Ubuntu and install in on the partioned drive D:   everything installed right, then after rebooting and loading into Ubuntu the screen says ~ Serious errors were found while checking the disk drive for /.    ~  If I ignore, it then says ~ Disk drive for /tmp is not ready yet or not present   ~     H E L P !?!?   THANKS !  J


How to write y i = β 0 + β 1 x i + β 2 x 2 i + e i in Latex code?

I'm a beginner of using R and Latex. Just wonder how to write yi = β0 + β1xi + β2x2i + ei by using Latex?


public int minCompletionTime() { // finds minCompletionTime   int time = -1;    for(Job j : jobs) {      if (j.getStartTime() == -1) {       return -1;     }   }    for (Job j : jobs) { //Calculate the minimum completion time      if (j.getStartTime() + j.time > time) {          time = j.getStartTime() + j.time;      }   }    return time; }    Can someone explain the loop condition? it looks new to for me. Thank you


For which primes p is $p^2 + 2$ also prime?

Origin —  Elementary Number Theory — Jones — p35 — Exercise 2.17 — For which primes $p$ is $p^2 + 2$ also prime? Only for $p = 3$. If $p \neq 3$ then $p = 3q ± 1$ for some integer $q$, so $p^2 + 2 = 9q^2 ± 6q + 3$ is divisible by $3$, and is therefore composite. (1) The key here looks like writing $p = 3q ± 1$. Where does this hail from? I know $3q - 1, 3q, 3q + 1$ are consecutive. $p$ is prime therefore $p \neq 3q$? (2) How can you prefigure $p = 3$ is the only solution? Does $p^2 + 2$ expose this? On an exam, I can't calculate $p^2 + 2$ for many primes $p$ with a computer — or make random conjectures.


Is there a way for me to know why I have Avahi?

For the past couple of weeks, I've been getting near-constant error notifications from Ubuntu (18.04 Cinnamon)  Network service discovery disabled Your current network has a .local domain, which is not recommended and incompatible with the Avahi network service discovery.  The service has been disabled.  I had never heard of Avahi in my life until these showed up.  According to , this is some sort of network software used for things like iTunes.  I have never used iTunes on this computer.  I haven't installed any programs that correlate to when these started to appear, as far as I can recall.  The last things I can think of that I installed are the Spotify and Discord clients for Linux, both a couple of months ago, at least. I'm prepared to disable it as outlined in the post I linked to, but I have to assume that it's there for a reason and some program is using it.  Is there any way for me to know why Avahi is active on my system so that I don't break something by disabling it?


I am trying to run the following commands as part of an MSBuild script:  for /R . %f in (*.targets) do copy /Y "%f" "C:\Program Files (x86)\MSBuild\Microso ft\VisualStudio\TeamBuild"   The commands is implemented in an exec the following way:  <Exec WorkingDirectory="$(SolutionRoot)" Command="for /R . %f in (*.targets) do copy /Y &quot;%f&quot; &quot;$(MSBuildExtensionsPath)\Microsoft\VisualStudio\TeamBuild&quot;" />   The command works fine from console, but when trying to run it from MSBuild I get the error:   Task "Exec"   Command:   for /R . %f in (*.targets) do copy /Y "%f" "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\TeamBuild"   f" "C:\Program was unexpected at this time. C:\Users\rd-build\AppData\Local\Temp\OH Test2\Continuous.BuildTargets\BuildType\TFSBuild.proj(98,5): error MSB3073: The command "for /R . %f in (*.targets) do copy /Y "%f" "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\TeamBuild"" exited with code 255. Done executing task "Exec" -- FAILED.   Any suggestions?


I am trying to get an online reference to the exact specs of my second hand bike. What are a) Some good techniques/things to look for? b) Some resources to help the dating process.  E.g I see that  visually exactly matches my bike, however the later models are closer in terms of exact specs, but none are an exact match.  I want to find out for examples which models of tiagra RD were 9 speed (which mine is) but I dont know of any good place to find such information. (This hobby seems to be all about latest/greatest :( )  Alternately I want to find out where to find/locate the model numbers of the various components. Other clues I have is a Truvativ crankset 53/39. FD RD and shifters all tiagra.


How to remove_filter that filters iframes in posts?

Which filter if removed allows iframes to be inserted into wordpress posts?


I want my page to look something like this (using \documentclass{article}):     text       title       text   but I can't get it right, it puts my title on the next page leaving my first text paragraph on separate page. What should I do?


for(int counter=0;counter<cells.size();counter++){             System.out.println("The name typed is "+name);             System.out.println("got to the loop");             String storedName=cells.get(counter).toString();             System.out.println("The cell name is "+storedName);               if(storedName==name){                 System.out.println("Found it!");                 break;             }else{                  System.out.println("Did not find it");             }          }   OUTPUT:  The name typed is JACK  got to the loop  The cell name is JACK  Did not find it  I don't understand why the if statement never returns true?


Lightning aura:iteration over two objects with dynamic key

I want to do simple thing - I want to iterate over list of two objects and use displayColumns as dynamic keys to get values from selectList object:  <aura:attribute name="displayColumns" type="String[]"/> <aura:attribute name="selectList" type="Object[]"/>   <table>     <aura:iteration items="{!v.selectList}" var="elem">     <tr>         <aura:iteration items="{!v.displayColumns}" var="col">             <td>{!elem[col]}</td>         </aura:iteration>     </tr>     </aura:iteration> </table>   In pure JS I would do: elem[col.value], but in lightning compiler returns:      expecting a positive integer, found 'col' at column 6 of expression:   elem[col.value]: Source   Is there any workaround without creating proper object structure in controller?


Open Attachment on Create of Child Record (2)

I have a requirement for a custom app I am building to open an attachment on the parent record in a new window on create of a child record.  I have parent object Quality_Assessment__c with child object Chart_Review__c. Quality_Assessment__c has a PDF attached to it in the Notes & Attachments section. When a user clicks to create a new Chart_Review__c record I need to have the PDF attachment on the Quality_Assessment__c record open in a new tab as well as the record create page for the Chart_Review__c record. Looking for help in generating the needed javascript for a custom button to accomplish this.  The 'Quality_Assessment__c' record will have a PDF file attached to it prior to the user clicking the 'New Chart Review' button.  My use case is to have users open the 'Quality_Assessment__c' record and perform what we call a Chart Review. To perform the Chart Review the user would click on a custom button called 'New Chart Review' which would do two things.  create a new 'Chart_Review__c' record displaying the new record edit page open the PDF attachment from the related 'Quality_Assessment__c' record. preferably on click of the button the new record page would open in existing tab and a new tab with the PDF would open simultaneously.


How do I make Windows 8's Start menu always open applications with "open as new window"?

Suppose I am using Notepad for one task, and I want to open up a new Notepad window for another task. When I open Notepad from the Start menu, it simply returns me to the Notepad window I already have open. In order to open up a new Notepad window, I have to right-click on the Start menu's Notepad icon and select "Open as new window".  Is there any way I can make "Open as new window" the default setting? I always want to open a new Notepad window, and I never want to return to the existing Notepad window (who would???).


Trying to wrap my head around what's going on under the hood when integration services is installed, and how that relates to SQL instances on the same machine.  Currently we are aiming to have a full BI stack with each component (SQL Server containing DW, SSAS and SSIS) on separate VMs so resource requirements can be siloed. We want to use the project deployment model for SSIS so are targetting SSISDB rather than MSDB, but the server with SSIS installed doesn't have a SQL instance to host SSISDB, so currently it's installed on the SQL box.  My question is, is it necessary to install a SQL instance on the SSIS box in order to host SSISDB or can it reside just within the integration services instance somehow? If so, does that mean that connecting to the SSIS instance through SSMS is just a legacy feature to manage MSDB or file system packages?   This isn't a question about licensing, it's about infrastructure.


I have an USB of 8 GB, it is somehow set to read only, previously it was working fine, but I think there is some virus or something that has turned it into a readonly system. I just want to remove everything from it and add other things. How can i do it? I do not have much knowledge, so you can tell me and I will put the output of commands that will help you diagnose the problem. I have tried a lot of solutions on stack overflow and ask ubuntu but no use


How do I clone a subdirectory only of a Git repository?

I have my Git repository which, at the root, has two sub directories:  /finisht /static   When this was in , /finisht was checked out in one place, while /static was checked out elsewhere, like so:  svn co svn+ssh://admin@domain.com/home/admin/repos/finisht/static static   Is there a way to do this with Git?


Haskell demonstration of equivalents to OOP Design Patterns

There are claims that OOP design patterns are irrelevant in functional languages. Are there code demos how each pattern can be implemented in Haskell? In particular, complete demo would also have to show how to represent objects, OO polymorphism etc.


Strange behavior when going to Edit Mode

I have a blend file. I got it from . A strange thing happens when you go to Edit Mode on "body" part. Well, the object called "body". Anyway, when you do that the half of the object is clipped, you go back to Object Mode, the clipped part goes back. I figured out that applying the existing subsurf modifier fixes this weird behavior.  And another thing. The origin point is cyan instead of orange.   Any thoughts on why this happens and what's with the origin point color?   (if you don't have an acc on blendswap)  Edited:   Thanks to Gonzou, his answer solves the mystery of the disappearing mesh.  The cyan dot mystery still remains. I looked through theme colors and didn't find any entry that controls that cyan dot. The "Active Object" entry only controls the outline color on that object. However, on a newly created object an origin dot color is orange (as it expected) and that "Active Object" entry controls an outline and dot colors.


Botulism, Garlic, Cold pressed Olive oil and mason jars

I make a product I invented called Maybe It's Marinade. Cold pressed extra virgin olive olive, pressed garlic as the base in three varieties, AoliOliO, Dill and Cayenne Pepper, garlic powder, and titch of salt. I package it in a 250 ml mason jar. I also place the jar in a celephane bag as part of its packaging. Recently, a public inspector noticed the product and sunk his teeth into it concerning Botulism risks.   I've been making this for eighteen years. No one has ever gotten sick. I designed the product to be stored in the cupboard. Using cold pressed olive, extra virgin olive oil I have never found the product to become awful, discolored, smelly, and I set some aside in my house on several occassions for months and tested it on myself and found nothing wrong.   The product is not a method of storing garlic in the oil, with the other ingredients in the recipe, it becomes a bread dipping oil, cooking tool, pasta sauce accessory.  The use of the mason jar provides a secure lid but a very reusable easy to open situation. I do not fill the oil to the top, so that the product can be shaken. Its a very interactive product if that makes sense, in the way that it's spoon accessible.   Can you provide some sort of pro and con overview? I only see articles on storing garlic in oil, not as an ingredient in a recipe? If there's a chance i will make people sick afer eighteen years, I may have to stop making it.  Thanks a heap.


How can a message encrypted with the public key be decrypted with the private key?

I've been reading about encryption and have a basic understanding of the concept. What I don't understand, however, is how a calculation with one key can result in a number that, through calculation with a different key, leads back to the same number you started with. Are they doing the same calculation (what I mean by this is for example: first multiplying the number with the first key, then dividing it with the second one)? If anyone could in a simple way describe how this works to me; and add some examples with actual numbers in them as well perhaps; that'd be be wonderful.


I've heard that there around 300 types of common cold.  Would it be possible to get infected by all of them and then achieve immunity for all of them, after having had the mother of all common colds?


How to communicate achievements on the StackExchange network in an academic CV or job interview?

I think contributions to StackExchange constitute a valuable thing for an academic to do. In many cases such contributions are directly related to the aims of an academic department: community engagement, building new knowledge, etc. This is particularly clear for sites that directly align with a particular academic discipline (e.g.,  , , ).  However, many people in academia have not heard of StackExchange. They often won't have heard about the reputation system. They may not be aware of the high quality content that often appears.  Thus, as an academic, how should you share your achievements on the StackExchange network in contexts where how your performance is evaluated has material consequences? (e.g., a CV, job interview, grant application context, promotion context)


How to create/write file under /usr in OS X 10.11

I was going to compile a php extension using phpize, but it reported some files not found. I googled and found some solutions,      In OS X 10.9, we can make a symbol link from /XCODE_PATH/OS_X_SDK/usr/include to /usr/include   But it seems that OS X 10.11 has some system policy which deny this operation. I even tried to boot in single user mode, but I just got   $ sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include /usr/include Sandbox: ln(14) System policy: deny(1) file-write-create /usr/include   Anyone knows how to fix this problem? Your answers or comments will be highly appreciated.


Why does it take so long for the translated version of tankoubon volumes to be released?

As far as I know, the English versions of tankoubon volumes for most manga series seem to be released within several months, if not years, of their original release in Japanese.  Even very popular mainstream series like Naruto and Fairy Tail have their English tankoubon counter-parts released months after their initial Japanese release.  Why is this the case?   If you consider the time it takes for subbed anime to be released, or even the (legal) translation of individual manga chapters done by companies like Crunchyroll or Shonen Jump, which happens on the order of days from the initial Japanese release,  it doesn't make much sense to me that releasing an English translation of tankoubon volumes would take so long, especially in the case of individual translation of the chapters, since all the companies would have to do is just compile them together.


What is the distribution of the variance of a sample from an unknown distribution?

I am sampling from a parameter with unknown distribution. I would like to calculate a 95% CI for the standard deviation of the sample.   @cardinal provides a nice general solution for calculating a CI in his [answer] to my previous question,  . And @erik-p provides an estimate of the standard deviation of the variance of the sample.  However, in order to calculate the 95%CI for the sample variance, it seems that I need to know the distribution of the sample variance. Is it possible to calculate such an estimate without knowing the distribution from which the sample was taken?  A related question is


Finding the original file of a symbolic link

So let's say I have a symbolic link of a file in my home directory to another file on a different partition. How would I find the target location of the linked file? By this, I mean, let's say I have file2 in /home/user/; but it's a symbolic link to another file1. How would I find file1 without manually having to go through each partition/directory to find the file?


Show $\mathbb{Z}[\sqrt{6}]$ is a Euclidean domain

I'm attempting to modify the proof the $\mathbb{Z}[\sqrt{2}]$ is a Euclidean domain to prove a similar result for $\mathbb{Z}[\sqrt{6}]$. The idea is to prove that $\mathbb{Q}[\sqrt{6}]$ is Euclidean which will then give the result for  $\mathbb{Z}[\sqrt{6}]$. According to Dummit and Foote's Abstract Algebra this should have norm $d(a+b\sqrt{6})=|a^2-6b^2|$. The result for $\mathbb{Z}[\sqrt{2}]$ relies on the fact that for any element $x$ in $\mathbb{Q}[\sqrt{2}]$ there is an element $x'$ in $\mathbb{Z}[\sqrt{2}]$ with $d(x-x')<1$, which is then used to show that for $x=qy+r$ we have $$ d(r)=d(x-qy)=d\left(y\left(\frac{x}{y}-q\right)\right)=d(y)d\left(\frac{x}{y}-q\right)<d(y) $$ But in this case, I'm having a hard time showing that we can find an element with $d(x-x')<1$ for $x\in\mathbb{Q}[\sqrt{6}], x'\in\mathbb{Z}[\sqrt{6}]$. Consider $x=a+b\sqrt{6}\in\mathbb{Q}[\sqrt{6}]$. The furthest this element can be away from any $x'=a'+b'\sqrt{6}\in\mathbb{Z}[\sqrt{6}]$ is when $|a-a'|=\frac{1}{2}=|b-b'| \Rightarrow$ $$ d(x-x')=\left|\left(\frac{1}{2}\right)^2-6\left(\frac{1}{2}\right)^2\right|=\frac{5}{4}>1 $$ What can I do to get around this issue?


My question is about modular inverses and fractions modulo $p$ So I was revising my contest notes, I was trying to think about each topic as if I was explaining it to a child, which is when I realised I did not actually understand what fractions modulo $p$ meant: I understand what something modulo $p$ means, it essentially tells us the remainder when that thing is divided by $p$. But what does a fraction modulo $p$ even mean? Like I can say $9 \equiv 2 \mod(7)$ , cause $9 = 7 \cdot 1 + 2$. But what does it mean to say $\frac{2}{3} \mod (7)$. I know how to calculate this, it is just $2 \cdot 3^{-1} \equiv 2 \cdot 5 \equiv 10 \equiv 3 \mod(7)$. But I want to know what it means. Like intuitively, what does this represent? Like what does it mean to say $\frac23 = (0.6666....) \equiv 3 \mod(7)$ If you were to explain it to a layman, how would you, like you'd say $9 \equiv 2 \mod(7)$ because that is the remainder on division by 7. But how would you explain to someone that $\frac23$ is $3$ modulo $7$? What I think it may mean is that if $\frac sr \equiv a \mod (p)$, then $p$ would need to divide the numerator of $\frac sr - a$. Thank you!


A group of people that (ARE) or A group of people that (IS) - proper usage?

Which sentence is right?  A group of people that are  OR  A group of people that is  I am aware that there is this grammar rule concerning relative pronoun that states something along the lines if 'X of Y that ABC' then ABC must agree in tense of the Y and not the X. However, I am not sure if this is also applicable for a group of people that ... because a number of people that (in this case must be) are...  It would be great if you guys could help explain!


I have two arrays  First array  array(     [0] => +970     [1] => +971     [2] => +972 )   And Second array  array(     [0] => 465465454     [1] => 321321355     [2] => 987946546 )   I want to merge them like this  array(     [+970] => 465465454     [+971] => 321321355     [+972] => 987946546 )   I try with array_merge but this gives me the result that I didn't want e.g.  $busi_code  = $page1_data->business_code; //array $busi_num  = $page1_data->business_number; //array  $business_phone_numbers = array_merge($busi_code, $busi_num);  echo '<pre>'; print_r($business_phone_numbers); echo '</pre>';   And its result is  [0] => +970 [1] => +971 [2] => +972 [3] => 465465454 [4] => 321321355 [5] => 987946546   So please guide me how can I achieve my required result.


How can I personalize my MacBook Pro Touchpad?

I'm running Ubuntu 12.04 LTS on a MacBook Pro 5.5. I'm just wondering if there is something that takes all the kinks out of the touch-pad. It works good, but it feels sluggish, double tap works about 75% of the time and sometimes while I it somehow selects something on a different page (although I'm not sure if that has to deal with the touch-pad and not weird laptop bugs for a new LTS)  If there are any programs, apps, commands aside from the built in system preferences > mouse and track-pad > touch-pad menu that allow someone to "optimize" touch-pad potential.


How to move files to high speed area of the disk?

I have a Samsung SSD as primary and Seagate barracuda 1TB HDD as Secondary Disk drives on my system.  Initially the read write rate of the HDD was pretty fast (100MBps and greater) but over time  (few months)  the speed read write for newer files have degraded to less than 10MBps with just 9% fragmentation. If I check the resource monitor nothing seems to be using the disk other than the program I am running.  I believe this is due to the physical structure of disk i.e head has to travel more when files are near centre of the platter than on the edge.  Regardless is there a way to identify areas of disk that are accessible faster and then move the frequently used files there?  EDIT: This is different question than defragmentation because I want to be able to select by myself which files and folders get to be in High speed area of the disk   I also suspect that maybe this disk is optimised for backups and not efficient for realtime use after first few Gigs.


Why does quantum computing only offer faster computational times for certain, specific types of problems?

Quantum computing has gained media attention about the exponential increase in computational speeds but only when dealing with specific problems which are prone to a quantum computational approach (such as cryptography)   Why does quantum computing only increase computational speeds for specific problems? Is this an inherent constraint with Quantum Computing or could we see Quantum Computing increase computational speeds “all around” in the future?  Thank you!  Ross


Is it possible to load an .las file directly into QGIS?  I would like to be able to load LiDAR data and to be able to do analysis based various feature attributes; e.g., elevation, classifications, etc. While LASTools (which was suggested in ) is a nice set of tools, it still didn't produce an .las point file that could be read by QGIS


accuracy and loss NAN for keras multi-label Neural network learning

When I ran a Neural Network modeling for multi-class labeling using Keras, the accuracy, loss, val_accuracy, and val_loss all seems to have nan at some point or other during the training process... Running environment and other info  Keras version: '2.4.0' TensorFlow version: '2.3.0' OS: Ubuntu 20.04.1    LTS GPU: Radeon RX 580 Series Python running in Jupyter Notebook    (there is no library version issue)  Thank you for you kind help. Code I used: # data import n prep data_irr = pd.read_csv( 'https://www.dropbox.com/s/97awk5f9rgn5k87/irrigation_machine.csv?dl=1') df_TRAIN = data_irr.sample( frac=  78./100 ) df_TEST  = data_irr.drop( df_TRAIN.index )  # TRAIN data X_train = df_TRAIN.drop( df_TRAIN.columns[ [0,21,22,23] ], axis= 1 ); X_train Y_train = df_TRAIN[['parcel_0','parcel_1','parcel_2']]; Y_train  X_train = X_train.to_numpy(); Y_train = Y_train.to_numpy()   # TEST data X_test = df_TEST.drop( df_TEST.columns[[0,21,22,23]], axis= 1 ); X_test Y_test = df_TEST[['parcel_0','parcel_1','parcel_2']]; Y_test.head()  X_test = X_test.to_numpy();  Y_test = Y_test.to_numpy()   ## model architecture  model1 = keras.Sequential() model1.add(             keras.layers.Dense( 64, activation= 'relu', input_shape= (X_train.shape[1],) ) ) model1.add(             keras.layers.Dense( 3, activation= 'sigmoid' ) )  model1.compile(                  optimizer= 'adam', loss= 'categorical_crossentropy', metrics= ['accuracy'] ) model1.summary()   model1.fit(              x= X_train, y= Y_train,             epochs= 15, validation_split= 20./100,             verbose= 2 )  The result of the training is: Epoch 1/15 39/39 - 0s - accuracy: nan - loss: nan - val_accuracy: 0.5481 - val_loss: -5.4487e-02 Epoch 2/15 39/39 - 0s - accuracy: nan - loss: nan - val_accuracy: nan - val_loss: nan Epoch 3/15 39/39 - 0s - accuracy: 0.5433 - loss: nan - val_accuracy: 0.7981 - val_loss: 1.8837e-07 Epoch 4/15 39/39 - 0s - accuracy: nan - loss: nan - val_accuracy: 1.1190 - val_loss: 0.3816 Epoch 5/15 39/39 - 0s - accuracy: nan - loss: nan - val_accuracy: 0.8221 - val_loss: nan Epoch 6/15 39/39 - 0s - accuracy: 0.5529 - loss: nan - val_accuracy: 0.9802 - val_loss: 0.2807 Epoch 7/15 39/39 - 0s - accuracy: 0.5473 - loss: nan - val_accuracy: 0.8893 - val_loss: 0.0128 Epoch 8/15 39/39 - 0s - accuracy: 0.5537 - loss: nan - val_accuracy: 0.8287 - val_loss: inf Epoch 9/15 39/39 - 0s - accuracy: 0.6186 - loss: nan - val_accuracy: 0.7756 - val_loss: 1522.9906 Epoch 10/15 39/39 - 0s - accuracy: 0.5905 - loss: nan - val_accuracy: 0.8085 - val_loss: 0.1824 Epoch 11/15 39/39 - 0s - accuracy: 0.6250 - loss: nan - val_accuracy: 0.8007 - val_loss: 0.0545 Epoch 12/15 39/39 - 0s - accuracy: 0.6514 - loss: nan - val_accuracy: 0.8980 - val_loss: 13932.9346 Epoch 13/15 39/39 - 0s - accuracy: 0.5457 - loss: nan - val_accuracy: 0.8000 - val_loss: nan Epoch 14/15 39/39 - 0s - accuracy: 0.5545 - loss: nan - val_accuracy: 1.9837e-07 - val_loss: -1.8476e+10 Epoch 15/15 39/39 - 0s - accuracy: 0.5409 - loss: nan - val_accuracy: 2.0768e-07 - val_loss: 0.5513 <tensorflow.python.keras.callbacks.History at 0x7f92602e0f98>


What is the command to insert inline code words into the text like this?   I know there are packages for inserting snippets into the code, but I need to insert keywords within the main text. I was wondering if there is a more convenient way to do that.


How to use mainfont type in math environment?

thanks for your help in advance. I was wondering how to use the mainfont type for some features in the math environment. For example, let's say I'm using "font A" which I've uploaded using some otf file for the text and for math environment I'm using default LaTeX math font. While font A doesn't have greek letters, I'd still like to use it for the math environment when feasible (for example, letters of the alphabet and words like "max," "lim," etc.) How can I get my math environment to use font A for this but default math environment for the items that aren't accounted for in font A?  (Disclaimer: I know people will say you shouldn't mess with fonts/math environments like this, and I generally agree, but choosing not to do something and not being able to do it are separate things--and I'd still like to know how!)


Partition of ${1, 2, ... , n}$ into subsets with equal sums.

The following is one of the old contest problems (22nd All Soviet Union Math Contest, 1988).  Let $m, n, k$ be positive integers such that $m \ge n$ and $1 + 2 + ... + n = mk$. Prove that the numbers $1, 2, ... , n$ can be divided into $k$ groups in such a way that the sum of the numbers in each group equals $m$.  I am trying to prove it but have gotten no idea yet.  For some small $n$'s we can see the validity of the assertion. In addition,   if $k= \frac {n}{2}$, then {$1, n$}, {$2, n-1$}, $\ldots$, {$n$,1} works, and  if $k =\frac {n+1}{2}$, then {$1, n-1$}, {$2, n-2$}, $\ldots$, {$n-1, 1$}, {$n$} works.  This observation doesn't seem to be of help for general solution.


I want to make some garlic and jalapeno infused oil. Maybe not jalapeno but some kind of Chile.


How to find matrix $A$ given $Ax=b$. Also $det(A)$ & $sum(A)$ are known.

Here is an example:  $A = \begin{bmatrix} 2 & 3 \\ 5 & 1 \end{bmatrix}$  $x = \begin{bmatrix} 3 \\ 8 \end{bmatrix}$  $b = Ax$ so  $b = \begin{bmatrix} 30 \\ 23 \end{bmatrix}$  Now i want to find $A$ using $x$ and $b$ matrices. How can i do that ? Some says there is a way to invert a non-square matrix (something like right and left) so i can find $A$, but i dunno how to do that.  Additional: What if i had $det(A)$ and sum of entries in $A$ (which is $-13$ & $11$ in this case).


Which packages are installed on Ubuntu desktop by default?

Is there a list of packages that are installed on a fresh install?  I know, there is the other question  But that doesn't show, what will be the output of  dpkg --get-selections | grep -v deinstall | cut -f 1   right after a fresh install of Ubuntu desktop?  I would like to compare the resulting remaining list with the packages I have installed at the moment, so I can find out, what changed on the system since install.


How do I go about replacing one character for another and then another character for another in one line and printing the result?  As an example, consider the following code:  string="1 33 4 a" echo ${string// /_} #prints 1_33_4_a   Now, I'd like to replace back underscores for spaces so I tried:  echo ${${string// /_}//_/ }   But this yields the error "bad substitution".  I know how to do it with variable assignment, I do not want that. I want do it in just one line, without using sed and as portable as possible.  This is just a challenge to myself which will hopefully be instructive.


Question about using MCMC to estimate posterior probability from a random sequence?

I start to study MCMC and Bayesian inference. Bayesian inference method usually needs to estimate posterior probability,like below:  $P(\theta|y)=P(\theta)*P(y|\theta)/NormalizationFactor$  $y={y_1,y_2,y_3,...y_N}$ is already known random sequence,and $p(y|\theta)$ and $p(\theta)$ are also known.  To my knowledge, MCMC is mainly used to generate samples from some specific complex distribution.  I'm confused about MCMC usage in this scenario, so my question to ask is how to use MCMC to estimate the $P(\theta|y)$ based on the above sequence $y$?  Moreover, because $\theta$ is a random variable, different $\theta$ conresponds to different $P(\theta|y)$, how to select optimal $\theta$ as current best estimate?


Can someone please verify my proof?     Is the collection $\tau_\infty = \{U:X-U$ is infinite or empty or all of $X\}$ a topology on $X$?   No. Let $X = \mathbb{R}$.  Clearly, $\{x\} \in \tau_\infty$ for all $x \in X$.  Set $\displaystyle{B = \cup_{x \neq 0} \{x\}}$. Clearly, $X - B = \{0\}$, but $\{0\} \notin \tau_\infty$. Since $\tau_\infty$ is not closed under arbitrary unions, it does not define a topology on $X$.


Is there a ring which satisfies $xy=1$ and $yx\neq 1$

I checked a lot of examples of non-commutative rings that came to my mind, but they weren't helpful. In particularly it's not the case for ring of matrices because of the multiplicity of the determinant. Any hints?