Function IsVarArrayEmpty(anArray As Variant)  Dim i As Integer  On Error Resume Next     i = UBound(anArray, 1) If Err.Number = 0 Then     IsVarArrayEmpty = False Else     IsVarArrayEmpty = True End If  End Function   It is returning true for uninitialized and false for initialized. I want to see if it has any data/content. However, the problem is I feel the above code is returning false even when there is no data in the array. How do I check that?   (I tried setting string s equal to the byte array. That was "". That means the array is empty, right?)


Good practices for proactively preventing queries from randomly becoming slow

We support several deployments of an in-house application based on SQL Server. We've had a problem several times now where some query that used to be quick and small suddenly becomes very slow or erratic, while not necessarily producing more data or being run on a larger dataset. Every time this happens, it is a different query that suddenly starts running slowly.  Whenever this happens, we have to spend some development time to debug the problem, maybe write the query again and benchmark against the previous version, etc. Yet the original query often worked just fine for years, and we had no prior indication that its execution time might explode. What are some good practices that would prevent issues of queries randomly becoming slow? What I am after is not "how to fix a query that we already observe being slow", but how to reduce the likelihood of queries becoming slow in the first place—a proactive approach, as opposed to reactive.  I need a way to force SQL Server to not try to optimize the query too much: I don't really need fast, I need consistent.  If there were some choices to have SQL Server be conservative in building the query plan, as opposed to trying to take advantage of data distributions and such, I'd be after them.


page numbering in frontmatter using double sided book class

I posted this qustion:    But after i registered lost access to it...  The second answer by @egreg works very well in the frontmatter, but as soon as i start contents list, the automatic blank pages in double-sided shows header and footer, which is unwanted. how do i change that?


Python Multiline Regex Search in Binary File

I'm trying to figure out a way to locate multi-line strings embedded in a binary file. The code I've got will identify non-multi-line versions of the pattern, but not the multi-line versions.  I've tried this with with re.findall():  import re a = open('file', 'rb') b = a.read() c = re.findall(b'[<]{2}.*?[>]{2}', b, re.MULTILINE)   And with re.search():  import re a = open('file', 'rb') b = a.read() c = re.search(b'[<]{2}.*?[>]{2}', b, re.MULTILINE) c.group()   In each case, the code will return non-multi-line substrings, but not those where a \n character appears in the string.  Any ideas?


What determines that which function should be disabled in a locked post?

In  locked post, it's only comments that have been disabled and other functions are still being accepted there (e.g. voting, answering, etc.) Which concrete factor is the reason for disability of one specific or more functions to be disabled in a locked post? For example why it's just the commenting feature that's been disabled in that post and other functions are intact?


How to make a brush (alpha image) using Cycles

I wonder how to render an alpha image to use for sculpting mode. This alpha image is called Height Map images.


Density of finite rank operator in compact operators on Hilbert spaces

Show the subspace of finite rank operators (defined on a Hilbert space) is dense   in the space of all compact operators.   I just started reading about compact operators and I saw this questions.  So far I learnt any finite rank operator on a Hilbert space is compact, to show it's dense in space of all compact operators, there must exist a sequence of finite rank operator $(T_n)$  such that it converges to compact operator $T$, but I'm not sure how I can construct this sequence, I may need to think about complete orthogonal sequence $\{e_1\:,e_2\dots\} $ of the Hilbert spaces, so I get  $$T(x)=\sum_{i=1}^{\infty}\langle T(x),e_i\rangle e_i$$ If I define $T_n(x)=\sum_{i=1}^{n}\langle T(x),e_i\rangle e_i$, this is off course a finite dimensional and compact operator. Can I say it's the sequence that converges to $T$? Or maybe I'm totally wrong, but I appreciate, if you give me some hints about this.


Approximating a discrete distribution with a continuous distribution: why add/subtract 0.5/N?

From onlinestatbook's chapter on "":        Why exactly do we subtract and add these 0.5/N values? How does that make our continuous formula more "discrete"?


Let $\{a_n\}$ be a bounded sequence of real numbers and $a_{n+1}\geq a_n - 2^{-n}$. Prove that $a_n $ is convergent.  My attempt: Suppose $a_n $ is not convergent then $\limsup a_n \neq \liminf a_n$. Let $\{x_n\}$ and $\{y_n\}$ converges to limsup and liminf. Then for some $x_p=a_{n_p}$ and $y_q=a_{n_q}$ we have $x_p-y_q>\epsilon$. where $n_q>n_p$. Also from given condition $x_p-y_q < \frac{1}{2^{n_p}}$. This is a contradiction for bigger $n_p$. Is this correct? Please help!


How to make tcolorbox breakable while expanding to the entire page on every page under each section

I'm trying to span the tcolorbox over entire page under each section. The MWE is as shown below (after referring to this ) \documentclass[11pt,letterpaper]{report} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage[english]{babel} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{lipsum} \usepackage{graphicx} \usepackage[many]{tcolorbox} \begin{document}          \newtcolorbox{ubox}     {         breakable,height fixed for=all,colback=white,arc=0mm,outer arc=0pt,width=1.01\linewidth,boxrule=.7pt,         before upper={\parindent24bp},left=1.2pt,right=1.2pt,top=0mm,     }          \section{Section 1}     \begin{ubox}         \lipsum     \end{ubox}     \section{Section 2}     \begin{ubox}         This is a short sentence in section 2, however, I would like the box to span the entire page as well.     \end{ubox}      \end{document}     However, as shown on the third page, the box does not expand to the entire page. I would like the box to span the entire page regardless of the length of the content.


I have clicked wrong keys and now im not able to turn it off and now i only see what was in the camera shaped box.


How can I reliably screen or block callers on a number-by-number basis?

Last night I got a telemarketing call on my Verizon Droid X. I was horrified, to say the least. I absolutely do NOT want telemarketers wasting my time and minutes with their B.S.  I looked into screening blocking calls through Verizon, but it seems Verizon only lets you block a total of FIVE numbers. I think this is unacceptable.  I went to the app store and there are a number of such applications available. From reviews and comments it's really hard to choose.   Is there a way to solve this problem? An app? A procedure? Something within the phone itself?  I'm using the soak release of Gingerbread, 2.3.3. I don't care about price. I just want something that is fast and effective.


Resolution troubles after upgrading to Ubuntu 17.10, xrandr will not add resolution

I upgraded last weekend, and my monitor (since long having run fine on 2560x1080_60.00) couldn´t get any higher 1920x1080. I tried adding a new resolution using xrandr but failed every time again.  A work around was returning to another kernel. Grub has available:  Found linux image: /boot/vmlinuz-4.13.0-16-generic Found initrd image: /boot/initrd.img-4.13.0-16-generic Found linux image: /boot/vmlinuz-4.10.0-37-generic Found initrd image: /boot/initrd.img-4.10.0-37-generic Found linux image: /boot/vmlinuz-4.4.0-97-generic Found initrd image: /boot/initrd.img-4.4.0-97-generic   And returning to linux image: /boot/vmlinuz-4.4.0-97-generic helped me to get the higher resolution back into the settings menu. With the newer kernel, it returned errors when trying to add modeline using xrandr.  I saw multiple questions on this, none of them (other than switching back to an older kernel) helped solve the problem.  Thanks and regards, Bill


A series about a multiverse with a central nexus and lots of crossovers from other series

I've been trying to find this series. I remember it came up as a possible solution to a different Identification question on this Stack, but I can't find it now.  Edit:  It was a book, and it was pulp fiction style if memory serves.  Someone below suggested The Number of The Beast, and I believe that to be correct.


Using fermat's little theorem and the chinese remainder theorem?

So I'm trying to find $9^{65}\pmod{77}$. What I've done: I used Fermat's little theorem and separated them into $9^{65}\pmod7$ and $9^{65}\pmod{11}$, where I got the remainders to be $4$ and $1$ respectively. Now, I have no idea what to do from this point. What is the best way to combine both to get the final answer?


Using image sequence of medical scans as volume data in cycles

I know it's possible to do this in BI, but I need your help to do this in cycles. For now, I have a setup to use an image sequence as volume but it only shows 1 slice/frame. I'm using generated texture coordinates for easy mapping (0-1 on each axis). The images are mapped on XY and I would like to use normalized frame# as Z coordinate to map the sequence as a volume.       Images sequence can be found  (I'm using 16-bit TIF files of MRBrain in this exemple).    Any solution is welcome but try to keep it simple and user friendly :).  Final Edit: I had a hard time choosing between Lemon's and PGmath's answers. Lemon's is more user friendly and flexible, and uses the image sequence without any change inside blender. PGmath's uses a 3rd party converter to make the sequence 1 single image, but allows GPU rendering. Well, ImageMagick's command line is : "convert +append *.tif anim.tif" from the folder where the sequence is unzipped. Not so hard. That's why I accepted PGmath's answer.      Now, i played with it, and here's the result.  The "volume" object contains the volume shader (playing with the color ramp gives funny things) and the boolean modifiers (turn them off to see the complete volume, but reduce the final density multiplier for better view). The "Slice Control" arrow empty controls the slice position/rotation. The "Texture Mapping" object controls...the mapping, if it need some tunning (position, rotation, scale, and then tiling if necessary?).


Story about a world of magic where science has been forbidden

I am looking for a book that I read in the 80s where magic is used to help with tasks and science is forbidden. What I recall is that the protagonist (I think a boy) has to move a something heavy like a rock or tree stump but doesn't have magic, or it hasn't manifested yet, but he gets the idea to use a stick as a lever, at which point he gets into some sort of trouble for using what he later learns is called science. A bit later in the story I think he finds a section in the library that he's never seen before, which contains books on the "forbidden" (science). Possibly in a post-apocalyptic world where science is forbidden because people remember it leading to catastrophe.


node above tikz path does not works with "--" but not "to"

I am struggling with the positioning of a node above a tikz path. The path is curved and connects two nodes with "to". Here is a MVE:  \documentclass[a4paper,twoside,11pt]{book} \usepackage{tikz} \begin{document}  \begin{tikzpicture}[scale=1,transform shape] \draw[->,thick,out=0,in=180] (1,0) to (5,1) node[above,pos=0.5,sloped] {text}; \draw[->,thick] (1,3) -- (5,4) node[above,pos=0.5,sloped] {text}; \end{tikzpicture} \end{document}   The node is above the line in the case with "--" but not with the "to". What I am missing here?  I am pretty sure I had something similar working in the past...


I would like to create a carc path macro (centered arc, that acts like circle, without changing the current position) in a way to be able to write :   \draw (0,0) carc(30:90:1) carc(30:90:2) carc(30:90:3);   I know how to do it with latex macro :  \def\carc(#1:#2:#3){++(#1:#3) arc(#1:#2:#3) ++(#2+180:#3)}   and then I can use :   \draw (0,0) \carc(30:90:1) \carc(30:90:2) \carc(30:90:3);   But I'm wondering, if there is a way to do this in pure TikZ ?  Is it a way to create new macros that acts like circle, rectangle, arc, ... on paths ?


Which test should I use for ordinal data?

In my experiment, I asked 50 participants to rank on a 5 point scale which voice they preferred. I summed each particpants' rating for each voice: the total for voice 1 is 95, the total for voice 2 is 186.  Am I correct in doing this? Or should I analyse the raw data?  Which test should I use for this data? Would a t-test work here? Alternatively I thought I could use a chi-square test.   I am interested in seeing if the preference for voice 2 is significant.


How to update return value from function when I am not using any global variable?

def dinner_completed():         counter=0         if counter==0:             k=False         if counter==1:             k=True         counter+=1         print('counter',counter)         return k      while not dinner_completed():         print('1')  Each time I check the function in a while loop, counter is getting initialized to 0 . I don't want to use global variables and my function have to return False only once and True the rest of times.


Specifing ip address for outbound connections on a multi ip host

one of my servers (Debian 5.0.6) has two public ip-address on the same interface. This used to work well for months but suddenly it is using "the wrong" ip addresses for outgoing connections. This is a problem because the reverse lookup will not match and emails therefore get spam points.  eth0      Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:81.169.180.51  Bcast:81.169.180.51  Maske:255.255.255.255           inet6-Adresse: fe80::21b:21ff:fe14:8e9c/64 Gültigkeitsbereich:Verbindung  eth0:0    Link encap:Ethernet  Hardware Adresse 00:1b:21:14:8e:9c             inet Adresse:85.214.157.120  Bcast:85.214.157.120  Maske:255.255.255.255   Kernel-IP-Routentabelle Destination     Router          Genmask         Flags Metric Ref    Use Iface 81.169.180.1    0.0.0.0         255.255.255.255 UH    0      0        0 eth0 0.0.0.0         81.169.180.1    0.0.0.0         UG    0      0        0 eth0   Currently it is using 85.214.157.120 for outbound connections. How do I get it to use 81.169.180.51?  Edit: The netmask of 255.255.255.255 is consistent with both documentation and DHCP response of the hosting company. Calling /etc/init.d/networking restart multiple times will eventually end up with the correct ip-address for outbount connections. But that is obviously not a stable solution. /Edit  Edit 2: To make sure that the host route is not related to my issue, I setup a local test network:  eth0      inet Adresse:192.168.0.2  Bcast:192.168.0.255  Maske:255.255.255.0 eth0:0    inet Adresse:192.168.0.3  Bcast:192.168.0.255  Maske:255.255.255.0  192.168.0.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0 0.0.0.0        192.168.0.1     0.0.0.0         UG    0      0        0 eth0   If anyone has an idea how to make sure that source ip-address 192.168.0.2 is used on outbound tcp connections, I'd be thankful. /Edit 2


null pointer exception while searching linked list

I  created a search method for a linked list.  It works correctly when I search for something that does exist in the list.  If I search for something not in the list, then I get a null pointer exception.  I don't see how its possible to get this exception.  Here is the method:   // these two search methods return the node containing the substring given public UNode search(String cityName) {     return search(cityName,this);//line 90 }//end search()------------------------------------------------------------- private UNode search(String cityName, UNode current) {     if(current != null)     {         if (current.getCity().getName().contains(cityName))         {             System.out.println("Node '" + current.getCity().getName()                      + "' has been found and returned.");             return current;         } else         {              return search(cityName,current.next);//line 105         }     }     else     {         System.out.println("No node containing the substring '"                  + cityName + "' can be found, returning null");         return null;     } }//end search()-------------------------------------------------------------   To my understanding, this is what happens when searching for something that does not exist:  The method keeps calling search() recursively with current.next, it gets to the last element and calls search(cityName, null), then since current is null, it says it is not found, and returns null.  Am I missing something here?  What am I doing wrong?  Should I just throw the null pointer exception?  Here is the method where I call the search method:  public static void uNodeTest(City[] cities) {       UNode unvisited = new UNode();      unvisited.addCities(cities);       String a = unvisited.getNext().getNext().getNext().getCity().getName();      System.out.println(a);      UNode current = unvisited;     while(current.getNext() != null)     {         System.out.println(current.getCity().getName());         current = current.getNext();     }     UNode phil = unvisited.search("not a city"); }   Stack Trace:  java.lang.NullPointerException at cityproject.UNode.search(UNode.java:105) . . . at cityproject.UNode.search(UNode.java:105)//(omitting repeats) at cityproject.UNode.search(UNode.java:90) at cityproject.CityProject.uNodeTest(CityProject.java:104) at cityproject.CityProject.main(CityProject.java:79)


How to exclude a Shader from direct the direct Lightning og a HDRI Background

I am new to to Light Path Node in Blender and was wondering if there is way of using a HDRI Background in the world settings while excluding specific Objects in the Scene from the direct illumination from the used Background? So that those excluded objects are getting a toonish kind of look. I just can´t get my head around this topic. Thank you for your help.


How do Ubuntu and Debian manage $HOME for users with sudo privileges?

I have a bash script myhome.sh containing only one line:  echo $HOME   The script's owner is a user:  $ ls -l myhome.sh -rw-rw-r-- 1 user user <date> <time> myhome.sh   In Ubuntu 16.04 and 17.10 I get:  $ echo $HOME /home/user  $ sudo echo $HOME /home/user  $ bash myhome.sh /home/user  $ sudo bash myhome.sh /home/user   In Debian Buster/Testing I get:  $ echo $HOME /home/user  $ sudo echo $HOME /home/user  $ bash myhome.sh /home/user  # WHY ? $ sudo bash myhome.sh /root   I don't understand why inside the script in Debian, if it's executed with sudo, I always get $HOME=/root while in Ubuntu I get $HOME=/home/user. Does anyone know what have the Ubuntu developers changed?


How to share "internet hotspot" access to a network on a second wifi adapter?

Can anyone assist with a linux routing question? Essentially I want to use an Ubuntu laptop to provide internet access to an attached network.  I have a Raspberry pi on a wifi network (192.168.42.0/24). Its ip address is 192.168.42.20.   Internet access is provided by a cell phone hotspot. (192.168.43.0/24). The internet gateway is 192.168.43.1  I have a linux laptop (Ubuntu) with two wifi cards - one on each of the above networks. (192.168.42.21 & 192.168.43.10)  I also have another network connected on the ethernet card which successfully shares the internet connection with clients. This network is 10.42.0.0/24.  The laptop is a DHCP server in this case and its ip is 10.42.0.1  I am trying to use the laptop to provide an internet access route for the Pi I have added the following iptable rules to the laptop. They are derived from the forwarding rules for the 10.42.0./24 network which as I say can connect to the internet.  -A FORWARD -d 192.168.42.0/24 -o wlx801f0281f02a -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -s 192.168.42.0/24 -i wlx801f0281f02a -j ACCEPT -A FORWARD -i wlx801f0281f02a -o wlx801f0281f02a -j ACCEPT ip_forwarding is enabled   I have added a route on the Pi. The route table now reads:  Kernel IP routing table Destination     Gateway         Genmask         Flags Metric Ref    Use Iface 0.0.0.0         192.168.42.21   0.0.0.0         UG    0      0        0 wlan0 192.168.42.0    0.0.0.0         255.255.255.0   U     303    0        0 wlan0   The Pi can ping through to both the other networks and both other networks can ping through to the Pi.  BUT ... the Pi still doesn't have internet access, although a device on the 10.42.0.117 happily reaches the outside world.  The routing table on 10.42.0.117 is exactly "parallel" to the Pi's:  Kernel IP routing table Destination     Gateway         Genmask         Flags Metric Ref    Use Iface 0.0.0.0         10.42.0.1       0.0.0.0         UG    0      0        0 eth0 10.42.0.0       0.0.0.0         255.255.255.0   U     0      0        0 eth0 127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo   What am I missing?


Is it possible to check the BIOS version of my computer on Ubuntu?

Is it possible to check the BIOS version of my computer from a running Ubuntu instance?


I'm a beginner in C programming, but I was wondering what's the difference between using typedef when defining a structure versus not using typedef. It seems to me like there's really no difference, they accomplish the same goal.  struct myStruct{     int one;     int two; };   vs.  typedef struct{     int one;     int two; }myStruct;


Can I view which cities are low on food or have no food without clicking each one?

I'm at a point where I have around 40 cities (I kept playing after winning just for fun) and the stats screen popped up for "Most Well Fed" and I noticed my number was extremely low. I have farmland up the wazoo, so I was wondering which cities weren't so well-fed so maybe I could work on getting those specific ones some food, or halt population growth there so they don't run out of food.  I can't seem to find any screen that will outline all my cities and how much food they have, but I don't really want to click through every single city to look at the stats. I know that when a city starts starving, the red citizen icon will start appearing to notify you of that, but I'd rather not wait until that point because that will affect happiness until that extra citizen dies off from the food shortage.  Is there any simple way to view the food (and possibly other) stats for each city all at once? Or perhaps some other way to find starving cities?


Touching a comment owned by a deleted user crashes Android app

Steps to reproduce:    Find a comment owned by a deleted user, like . Touch it (as you normally would when trying to upvote or flag). Observe as app stops responding. Wait about 8-9 seconds. Observe crash. Look up to the sky, throw your hands in the air, and scream "WHY???!!!" because you really wanted to upvote that comment. * optional   Could this be unborkified?


difference between twice as ... as and twice more than

Do both of the following sentences have the same meaning?       1- My salary is twice higher than yours.   2- My salary is twice as high as yours.


SQL Server 2012 change query result position

Traditionally in SQL Server while executing a query the result is displayed below the query dividing the screen horizontally.  Is there any settings that can be done to displays the result to the side (splitting vertically)?  Thanks in advance.  Note: I am using SQL Server 2012.


Flight Search from anywhere to a specific destination

Many flight search engines allow you to pick a departure airport and search for flights to anywhere. E.g.  gives you a nice map with prices next to destinations for a set of dates and an origin you selected. We covered this question widely in  here on our site.  I want to have the reverse, i.e. I know my dates and my destination (for a one-way flight) and I want to know from where it is cheapest to fly there. Is there any flight search engine out there to achieve this?  Google flights does not do this, they pre-compile the "from"-field if I try to leave it empty. I know I could use  with a wide range of departure airports but that does not give me low-cost carriers and I do not trust the matrix results for such a wide range of parameters anymore.  Edit: It has been asked in comments why I would want such a feature. Well currently I'm planning my summer vacation and I would like to spend one week traveling around basically anywhere in that area before I have to go to a specific location at a specific time. One of the main price and convenience factors for me is that final flight so I would like to optimize it first. I'm sure I'm not the only one with that kind of constraints.


I've just installed 64-bit Ubuntu 11.04 and after I updated it, the clock stopped displaying the right time. It's now 8 hours behind my normal time. I've checked the Time and Date settings and the Location field is correct. What's even weirder is that the time displayed in Time and Date Settings adjusts itself after a few seconds and is correct. The time displayed in the task bar remains the same, however.  Any ideas?


Getting equation from differential equations

I have:  $\dfrac {dx} {dt}$=$-x+y$  $\dfrac {dy}{dt}$=$-x-y$  and I am trying to find $x(t)$ and $y(t)$ given that $x(0)=0$ and $y(0)=1$  I know to do this I need to decouple the equations so that I only have to deal with one variable but the decoupling is what I am having trouble with  Do I set them equal to each other and then just move like terms to separate sides getting two different equations and then integrate?


I have a Toshiba flash drive that I'm trying to wipe clean, but the thing is that the files won't go away. I have tried everything:   the simple left click -> format, a message appears: windows can't complete the format process disk management and deleting the partition, once I create a new partition the files appear back as if nothing happened DISKPART command in CMD, once I hit clean it says the process was successful but the files are still there, it should be mentioned that CHKDSK doesn't show anything out of the ordinary third party software: mini partition tool, Rufus, easeus, I've tried wiping data by putting 0's which is an option in mini partition tool, but this doesn't seem to be solving anything virus scan with esetnod shows no signs of malware am    I missing something? is there anything I can do?


I have to show that the domain defined by the half unit circle: $\left \{ \left ( x,y \right )\in \mathbb{R}^2: x^2+y^2\leq 1, x\geq 0 \right \}$ for the function $f:D\rightarrow \mathbb{R}$ is closed (the function is $f(x,y)=2xy^2-2x^2$), so that I can argue the function has a min/max value. I have shown it is bounded and continuous.


Use residues to evaluate $\int_0^\infty \frac{\cosh(ax)}{\cosh(x)}\,\mathrm{d}x$, where $|a|<1$

Use residues to evaluate $$ \int_0^\infty \frac{\cosh(ax)}{\cosh(x)}\,\mathrm{d}x $$ where $|a|<1$.  Try considering the integral of the form  $$ \int_C \frac{\exp(az)}{\cosh(z)}\,\mathrm dz, $$ where $C$ is the contour given by $y=0,\, y=\pi,\, x=-R,\, x=R$.


Is it possible to photograph the aura of a person?

I have heard that auras can be recorded in photographs, but I don´t know how to do it. Does it have to do with filters?


Sum of two kernel is also a kernel, how can we prove that?

Suppose that k(·, ·) and k 0 (·, ·) are kernels. Prove that l(·, ·) where l(x, y) = k(x, y) + k0 (x, y) is also a kernel.  I am having trouble proving this, can you help?


"You're on the featured tab" and no selected tabs in vicinity

I was browsing featured questions previously, but when I clicked on a tag that didn't have them, I ended up seeing "You're on the featured tab" message, while the tab was absent. And it's confusing! Where's the tab I'm currently on?    It should at least be there to allow me to quickly focus on the area where I should look for other tabs, because sometimes I look around the page for almost a minute trying to find where it all went wrong.


This a very elementary question, but I am quite new to set theory. I came across this quote on the Wikipedia page for "Hereditary Set".  In formulations of set theory that are intended to be interpreted in the von Neumann universe or to express the content of Zermelo–Fraenkel set theory, all sets are hereditary, because the only sort of object that is even a candidate to be an element of a set is another set.  Is this quote saying that all sets in ZFC are hereditary sets? How does one then construct a set such as ℝ? Thank you


Where can I find the official documentation on review?

On Stack Overflow you can make reviews, but there is a limit. This limit is not static. Since I began reviewing, rules governing the review limit has changed a lot!  Where can I find the last updated rules on reviews?


In what sense is the proper/effective action $\Gamma[\phi_c]$ a quantum-corrected classical action $S[\phi]$?

There is a difference between the classical field $\phi(x)$ (which appears in the classical action $S[\phi]$) and the quantity $\phi_c$ defined as $$\phi_c(x)\equiv\langle 0|\hat{\phi}(x)|0\rangle_J$$ which appears in the effective action. Even though $\phi_c(x)$ is referred to as the "classical field", I don't see why $\phi(x)$ and $\phi_c$ should be the same.  In what sense, therefore, is the effective action $\Gamma[\phi_c]$ a quantum-corrected classical action $S[\phi]$? How can we compare the functionals of two different objects (namely, $\phi(x)$ and $\phi_c(x)$) and claim that $\Gamma[\phi_c]$ is a correction over $S[\phi]$?  I apologize for any lack of clarity in the question and the confusion I'm hoping to clear up.


Add LaTeX with version number to LaTeX document

I love that in LaTeX it is possible to stylize the name of the language by typing \LaTeX, and I noticed on wikipedia that the proper way to stylize LaTeX2e is as follows:     Is there a simple way to add this stylized latex version number to a document?  Thanks!


Layover in Frankfurt for 1h40m - is it enough? What happens otherwise?

I have a flight from Stuttgart to Frankfurt whose ETA at Frankfurt is 9:10. I have a connecting flight from Frankfurt to Chennai at 10:50. Both the flights are booked as part of the same ticket. So, there is a layover of 1h40m at Frankfurt airport. Would this be enough? I have been watching the terminals closely and I find that my first flight exits me at A2-3 and the connecting flight is at C15/C14. IS there a passport control and security check along the way and would this time be sufficient?  If i miss the flight, what happens?   Both flights are operated by Lufthansa


How to build a custom FreeBSD release without root privileges?

I am trying to build a custom FreeBSD disk image from source which I could then load with bhyve.  Here's the script I use:  export MAKEOBJDIRPREFIX="$HOME/obj" export CHROOTDIR="$HOME/var" ncpu="$(sysctl -n hw.ncpu)"  set -e     cd  mkdir -p obj mkdir -p var  svn co http://svn.freebsd.org/base/head ./src cd src make -j$ncpu -DNO_CLEAN buildworld buildkernel  cd release make release -DNODOC -DNOSRC -DNOPORTS make install DESTDIR=../../var   My problem is that make release fails.   What is wrong?    Here are some parts of the make release error message:     ...  .:      user (0, 1001, not modified: Operation not permitted) bin:    user (0, 1001, not modified: Operation not permitted) boot:   user (0, 1001, not modified: Operation not permitted) boot/defaults:         user (0, 1001, not modified: Operation not permitted) boot/dtb:         user (0, 1001, not modified: Operation not permitted) boot/firmware:         user (0, 1001, not modified: Operation not permitted) boot/kernel:         user (0, 1001, not modified: Operation not permitted) boot/modules:         user (0, 1001, not modified: Operation not permitted) boot/zfs:         user (0, 1001, not modified: Operation not permitted) dev:    user (0, 1001, not modified: Operation not permitted) etc:    user (0, 1001, not modified: Operation not permitted)       ...  -------------------------------------------------------------- >>> Distributing everything -------------------------------------------------------------- cd /usr/home/m/src; make -f Makefile.inc1 distribute ===> lib (distribute) ===> lib/csu (distribute) ===> lib/csu/amd64 (distribute) cd /usr/home/m/src/lib/csu/amd64;  make install installconfig -DNO_SUBDIR DESTDIR=/usr/home/m/obj/usr/home/m/src/release/dist/base SHARED=copies install  -o root -g wheel  -m 444 crt1.o crti.o crtn.o Scrt1.o gcrt1.o /usr/home/m/obj/usr/home/m/src/release/dist/base/usr/lib/ install: /usr/home/m/obj/usr/home/m/src/release/dist/base/usr/lib/crt1.o: chown/chgrp: Operation not permitted *** Error code 71       ...


Can I use batteries with a higher-than-recommended current?

I have a device that says it takes a 23A, 12V battery. I ordered a new battery and was mistakenly sent one with 27A and 12V - same voltage, higher current. Is it safe to use this battery in the device, or will it break things? Apologies for what must seem like a noob question; I'm not an electronics person. I have found  but it talks about capacity instead, and I'm not 100% sure whether that changes the answer or not.


I bought a bag of peeled garlic cloves as a convenience(I know, shame on me) I stored the unused cloves in the fridge and the began to show purple areas on the cloves. I don't think this is anything harmful but my partner didn't like it and insisted I throw away what was left. Is this just another natural color change for garlic such as the blue/green or green colorations that can occur. Anyone have a definitive answer? I'm not trying to one-up her, just trying to be safe.


How do you disable Siri permanently on macOS Sierra (10.12.6)?

I work in security as an intern, and I've been asked by my boss to look into disabling Siri on macOS Sierra. I noticed that there's no way to prevent users from re-enabling Siri even if it's disabled by an administrator.  I've tried using "csrutil disable" in Recovery Mode and editing Siri's .plist files, but it seems to have no effect. Is there any way to completely prevent any user from running Siri on macOS Sierra?


Estimating costing for entities on Azure VMs

We are looking of moving our hosting solution over to Azure (we are a microsoft dev house so it makes sense). It just seems difficult to estimate costing for our hosting solution.   To give a simple rundown of our scenario. Our application is a simple asp.net frontend that backs onto an SQL Server database. We have a two tier setup on a VPS provider with 1 VM for the web box and 1 VM for the SQL box. When a customer comes onto our hosting solution they get a web application setup in IIS on the web box and a database connected on the sql box which talk to each other and the user is provided a web link to use (multi tenant setup isnt in the pipeline at this point). Currently we pay a one of monthly cost to the VPS provider and that covers everything.  Now moving to azure when we are looking at more of pay for what we use setup this changes the game a bit. What im wanting to do is to add a test company to the azure setup (we have a proof of concept copy in azure now) and simulate a days usage through it and than want to check the costs that it racks up on our account. Than create another test company and simulate a days usage and see what costs come from that. I was thinking once we've got so many test companies on the box we could than check the costs and average out that across the amount of companies and give us an estimate of how much an average company will cost us per day. Let me know if I'm being silly at this point? I would think this kind of cost forecasting would be pretty common.  The problem is that the only thing we seem to be able to do is check our account every morning and see what the cost was for the previous day, it seems very difficult if not impossible to drill down more costs. We can see each thing that we use on our account page (storage, cpu, input output) but it's hard to tie these back to actual daily costs.  Can anybody give advice on achieving what we are looking for?


Can't rename files on desktop via hotkey in Ubuntu 20.04 LTS

In previous versions of Ubuntu (16.04, 18.04) I renamed the files on the desktop using the F2 hotkey. But in Ubuntu 20.04 I can't do this. This is possible only by right-clicking mouse on the file and selecting the "Rename" option that is very inconvenient. How to make the system allow me to rename desktop files using a hotkey?  I also tried to find something on Google, but I did not find anything useful.  But in nautilus I can rename file using hotkey.


AES-CTR key reuse attack with same IV and known plain text

this is from an IT Security exercise which my friend and me cannot solve.  Given   2 AES-CTR stream-cipher encrypted files Same known initalizing vector Same (unkown) key Same 128bit Counter initialized with 0 Files are .png so there is known plain text in both files (the file header)   Our approach was to use the known equivalence of   $E(A) \oplus E(B) = A \oplus B$  From there the only option we see is to brute force $A$ and $B$ for the known $\oplus$ product.  Is there a smarter way to get $A$, $B$? Thanks for any hints!


Set up a dedicated server to run 2 Ubuntu partitions

I am having a headache looking for a tutorial. So I gave up and ask all Ubuntu experts. Is it possible to have a dedicated server with Ubuntu OS then partition or create another volume that runs the same OS? Then assign unique IPs to each partition?  Then install software applications and they will both run differently?  If yes, is there a tutorial on how to do it? Or is someone offering a service to do it for a minimal fee? Thank you!


Why take the square of the difference between the label and the prediction? What is the advantage of ?


Suppose I have  a bivariate normal $(x,y)\sim \mathcal N(0,\Sigma)$ .  Is there an easy formula for the expectation $\mathrm E(x\mid y>0)$ ?


Is it possible to add an additional condition to join statement created by django ORM?  What I need in SQL is  'SELECT "post"."id", COUNT("watchlist"."id") FROM "post"   LEFT OUTER JOIN "watchlist"      ON ("post"."id" = "watchlist"."post_id" AND "watchlist"."user_id" = 1)   WHERE "post"."id" = 123  GROUP BY …   In django most of this is  Post.objects.annotate(Count('watchinglist')).get(pk=123)   But how can I add AND "watchlist"."user_id" = … into JOIN condition with django ORM?  Adding it to filter fails to get Post objects with no associated objects in watchlist.


Consider a piece of paper. If I pull on it in the right way it tears into two pieces. However, if I push those two pieces together, they do not spontaneously form a single piece. What happens at the microscopic level when the paper tears such that the process is irreversible?    My instinct is that in the fully formed piece of paper the fibers are strongly interwebbed, and so there is a large amount of (electrostatic?) energy stored at the boundaries between the fibers. To tear the paper, one must overcome this barrier, but I don't see what could have happened to make it difficult to re-introduce all those surfaces with one another. It almost seems like an entropy argument might work but I'm not sure how.


I want to replace Mailbox with something similar in pure Gmail. But I miss the way Mailbox shows the conversation count next to each folder.  Is there a way to do this for Gmail?


Let A, B, C be sets such that $A\cap B=A \cap C$ and $ A\cup B=A \cup C$. Prove that $B=C$

How can I proof this. Any help is appreciated


sp_send_dbmail unable to execute from service broker activation sp

I'm using Service Broker to [maybe] monitor my database events, so I have my activation sp in some user database and it should react on some events by sending e-mail to admin. But it fails with the error     The EXECUTE permission was denied on the object 'sp_send_dbmail',   database 'msdb', schema 'dbo   while trying to use sp_send_dbmail.  How can I manage the permissions in my case?


How can I export sublayers to png in Adobe illustrator?

A designer did a design for me.  It is in Adobe illustrator.  In order to write my program, I need to export sublayers one by one to .png files.  How can I do that?


How can I get stock quotes using Google Finance API?

I'm looking for access to financial data from Google services.   I found  that gets the stock data for Microsoft.  What are all the possible parameters that Google allows for this kind of HTTP request? I'd like to see all the different information that I could get.


Proper way to run and fish electrical wire in Canada?

This is my first DIY electrical project, so I am looking for some advise about the proper way to run the following 3 new circuits that I'll need for a basement kitchen that I am building:   I am currently reading the "Canadian Electrical Code, Part 1" in preparation for this DIY electrical work, but it creates a lot of questions that I am hoping someone with experience can help me with.  Most of my ceilings in the basement is drop-ceiling, covering exposed joists above. All the existing wiring is stapled to the bottom face of the joists, which according to CEC is not allowed anymore, so I cannot do it that way, correct? I am basing this on Rule 12-514-b:   Cables shall not be run on or across the lower faces of basement  joists, unless suitably protected from mechanical damage.   So I guess that means that my only option is to drill holes through all the joist and run the cables that way. This creates 2 questions:  Q1) What do I do when joists have HVAC ducts taking up the space between the joists that I need to cross? I know that cables require a minimum separation of 25mm from heating ducts, so what are my options? What kind of "mechanical protection" do I need to use, if I do need to staple to the bottom of the joist?  Q2) I have one 3-wire circuit and two 2-wire circuits to run. Can they all be run in the same hole? I can't find any info in the code about how many NMD90 wires are allowed in one joist hole...  Next, there's the question of how to run the wire over the part of the ceiling that is not accessible to me. There's a dry-walled, dropped section of the ceiling running along the entire length of the basement, and that I need to cross before I can get from the panel to the side of the house where the drop-ceiling is. What are my options for crossing that space, considering that I cannot support the cable every 1.5m as per Rule 12-510-1-a, without completely opening up the ceiling?   I found this rule about fishing wire:  == 12-520 Fished cable installation ==  Where the cable is used in concealed wiring and it is impracticable to  provide the supports required by Rule 12-510, and where metal sheeting  or cladding, metal joists, metal top or bottom plates, or metal studs  are not used, the cable shall be permitted to be fished.   So my last question is:  Q3) Did I understand correctly that I can simply fish the wire over the obstruction w/o any sort of conduit? What if that space contains metal HVAC ducts? Do I need to use some sort of conduit then? Is NMD90 wire even allowed to be run through conduits? What are my options?  Any advice would be greatly appreciated!


If $f \in L^p(\mathbb{R})$ then $\lim_{x \rightarrow \infty} \int_x^{\infty} |f(t)|^pdt=0$ where $ p \in (1,\infty)$ I tried to use this  but if $x\to\infty$, also $a\to\infty$, so $\int_a^{\infty}|f(t)|^p dt$ is not a constant. So, I can no longer find how to proceed by any other means, could you help me with this?


Does anyone know how to import Sparameter (touchstone) files into ltSpice and how to use them? I have downloaded s3p format file, but I don't know how to use it. I cant find any information in the Internet.  Thank you


Package installation - Outdated repository

all  Today, when I wanted to install some packages from MikTeX 2.9, I found that I cannot do so with the error:      The remote package repository is outdated.   I have tried several repositories already and they all gave the same problem. I have tried to re-download the MikTeX and checked. The problem still arose. What can I do to fix the problem?


What is the difference in meaning among these sentences?

Walking is good exercise. Walking is a good exercise. Walking is a good form of exercise.     I'd like to know the difference in meaning among these sentences. Thanks a lot.


Can I transfer from Pokémon Moon back to Pokémon X?

I have tried to use Pokébank to transfer xerneas from Moon back to X. Is there a way to do this? I need to transfer back.


Iterate through array of structs with unknown size struct member in C

I know that there are a many similar questions out there on stackoverflow.com but I couldn't figure out a solution for myself. After quite some time on research, my brain is broken now even though I think the task I want to do is relatively simple.   So I have two structs:  struct files_t {     file_t *file; };  struct file_t {     unsigned char *bytes;     unsigned int len; };    The first struct files_t contains a unknown amount of structs of the second struct file_t. The second struct file_t contains an array of unsigned char which represents the bytes of the file_t and the length of this bytes-array.   Then I create myself a pointer to a files_t struct:  files_t* files;   My question now is: How can I iterate through this files struct pointer (Pseudocode: for each file in files) when the amount of file_t's in it is unknown at compile time and also the size of each file_t is unknown at compile time?


My minecraft keeps crashing after about 25 seconds of running

My Minecraft keeps crashing after a couple seconds of running. I've read online about this issue and can't find anything. It says this after the crash.  [12:24:13] [Client thread/INFO]: Setting user: nkoak28 [12:24:13] [Client thread/INFO]: (Session ID is token:73f4a663d7d6417e96cee15634624bbf:d329cba1538248ba85a724c1ddbe7098) [12:24:14] [Client thread/INFO]: LWJGL Version: 2.9.4 [12:24:15] [Client thread/INFO]: Reloading ResourceManager: Default [12:24:16] [Sound Library Loader/INFO]: Starting up SoundSystem... [12:24:16] [Thread-6/INFO]: Initializing LWJGL OpenAL [12:24:16] [Thread-6/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org) [12:24:16] [Thread-6/INFO]: OpenAL initialized. [12:24:17] [Sound Library Loader/INFO]: Sound engine started [12:24:18] [Client thread/INFO]: Created: 512x512 textures-atlas [12:24:31] [Server thread/INFO]: Starting integrated minecraft server version 1.8.8 [12:24:31] [Server thread/INFO]: Generating keypair [12:24:31] [Server thread/INFO]: Preparing start region for level 0 [12:24:33] [Server thread/INFO]: Changing view distance to 12, from 10 [12:24:33] [Server thread/INFO]: nkoak28[local:E:5442333b] logged in with entity id 339 at (-120.06118661740985, 68.0, 270.1459368633843) [12:24:33] [Server thread/INFO]: nkoak28 joined the game # # A fatal error has been detected by the Java Runtime Environment: # #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007fffd6c7d5d3, pid=7808, tid=5780 # # JRE version: Java(TM) SE Runtime Environment (8.0_25-b18) (build 1.8.0_25-b18) # Java VM: Java HotSpot(TM) 64-Bit Server VM (25.25-b02 mixed mode windows-amd64 compressed oops) # Problematic frame: # C  [ig7icd64.dll+0x6d5d3] # # Failed to write core dump. Minidumps are not enabled by default on client versions of Windows # # An error report file with more information is saved as: # C:\Users\pc\AppData\Roaming\.minecraft\hs_err_pid7808.log # # If you would like to submit a bug report, please visit: #   http://bugreport.sun.com/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # AL lib: (EE) alc_cleanup: 1 device not closed Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release


How do we know that light isn't redshifted by space itself?

Do we know if light is red-shifted by traveling through space? If it isn't, how do we know? I guess my pondering has lead me to wonder if the observed accelerating space-expansion is a misinterpretation.   If light is red-shifted by traveling through space, we may be able to re-interpret Hubble's equation (I know, that might be heresy) as  $redshift = SomeConstant*d$ which would imply that distant objects aren't necessarily accelerating, the light we view is increasingly redshifted for more distance objects, independent of them moving away from us. Then, maybe we don't need dark energy anymore.?.


How is this command legal? "> file1 < file2 cat"

Assuming file2 already exists, the command   > file1 < file2 cat   appears to be copying the content of file2 to file1.  But I cannot understand this structure.  I understand that "Nothing" is being directed to file1 (creating or erasing its content). Then the content of file2 is being directed to file1.  Why is cat after file2? How does it know to cat file2 if the operands are not in the correct order?


Cannot install .deb pakages using software centre ubuntu 17.04

Today after installing ubuntu I encountered a problem when I was trying to install chrome  I first downloded the file then when I clicked software centre got opened I clicked install button many times but it didn t get installed


After logging in, there's a black screen and my cursor, nothing else! in Ubuntu 12.10

I've been using Ubuntu(12.10) for a long time, and recently, my Ubuntu went through yet another update.  The whole update prompt showed up, following by a password prompt, and finally the good ol' progress bar...  Everything went well, and later on, I shut down my computer.  The next day, I turned my PC on, went to the login screen. I went ahead, and logged in, but after that, all I could see was a black screen, and my cursor!  I checked the forums, and got various tips, none of which worked...  Now I'm stuck with an Ubuntu installation that's completely useless.  One more thing:  I even tried logging in through Guest, but same problem! :\  My Computer Specs: Motherboard: Intel DG41WV Processor: Intel Core 2 Quad Q6600 @ 2.40GHz Graphics: Intel G41 Express Chipset RAM: Dual Channel, DDR3 2*2GB (4096 MBytes) HDD: Seagate 500GB SATA   ---- DETAILED INFO ----  To be a little more precise about my problem, after I log in, I can see a black screen and my cursor. Plus, importantly, I was able to see a login screen, hence I'm sure Ubuntu is rendering properly, and also pretty sure that there's no problem with the drivers (Otherwise I shouldn't even get a login screen, right?).  Anywho, another (probably) important thing is that, after logging in, I can hit Ctrl+Alt+1 and get up a recovery console.  The only thing that doesn't load is my actual GUI desktop  Then, I ran unity from the recovery console, it went through a few commands, got stuck at OpenGL for a few seconds, then zoomed throught many more lines of code, and ended up with this:  ERROR 2012-01-03 20.51.23 unity.launcher.Icon TrashLauncherIcon.cpp:62 Could not create file monitor for trash url: Operation not supported  *** glibc detected *** compiz: malloc(): memory corruption: 0x09c861d6 ***   After that. back at Ctrl+Alt+F7: Desktop Background + Cursor  So back to the terminal again, I had to hit Ctrl+C to get back again.  now, I typed unity again, and this was the output:  WARNING: no DISPLAY variable set, setting it to :D compiz (core) - Info: Loading plugin: core compiz (core) - Info: Starting plugin: core unity-panel-service: no process found   so now I did a sudo service lightdm restart :  X10: fatal IO error 4 (Interrupted system call) on X server ":0" after 131 requests (130 known processed) with 0 events remaining. lightdm stop/waiting lightdm start/running, process 2852   Im back at the login screen, and I login again, now Im back to black screen (Yes, I lost the Desktop Background as well)  So, once again, I try unity (same response as last time):  WARNING: no DISPLAY variable set, setting it to :D compiz (core) - Info: Loading plugin: core compiz (core) - Info: Starting plugin: core unity-panel-service: no process found   And still a black screen! :\


How do I prove that the standard definition of prime ideal is equivalent to that of Krull's?

Definition Let $R$ be a commutative ring and $I$ be a proper ideal of $R$. Then $I$ is prime if and only if $\forall a,b\in I, a\in I$ or $b\in I$.  Let $R$ be a commutative ring and $P$ be a prime ideal of $R$. Let $I,J$ be ideals of $R$ such that $IJ\subset P$. How do I prove that $I\subset P$ or $J\subset P$? (which is the Krull's definition)?


Generate uniformly distributed weights that sum to unity?

It is common to use weights in applications like mixture modeling and to linearly combine basis functions. Weights $w_i$ must often obey $w_i ≥$ 0 and $\sum_{i} w_i=1$. I'd like to randomly choose a weight vector $\mathbf{w} = (w_1, w_2, …)$ from a uniform distribution of such vectors.  It may be tempting to use $w_i = \frac{\omega_i}{\sum_{j} \omega_j}$ where $\omega_i \sim$ U(0, 1), however as discussed in the comments below, the distribution of $\mathbf{w}$ is not uniform.  However, given the constraint $\sum_{i} w_i=1$, it seems that the underlying dimensionality of the problem is $n-1$, and that it should be possible to choose a $\mathbf{w}$ by choosing $n-1$ parameters according to some distribution and then computing the corresponding $\mathbf{w}$ from those parameters (because once $n-1$ of the weights are specified, the remaining weight is fully determined).  The problem appears to be similar to the  (but, rather than picking 3-vectors whose $ℓ_2$ norm is unity, I want to pick $n$-vectors whose $ℓ_1$ norm is unity).  Thanks!


Remap Menu to Control key (Ubuntu 16.04)

I am running Ubuntu 16.04 in a VirtualBox on Microsoft Surface Pro (2017). Unfortunately that keyboard doesn't have a right control key, but just a menu key on the right. That's why I want to swap the menu key for right control key.  I tried to edit /usr/share/X11/xkb/symbols/altwin by changing this   // Menu is mapped to the Menu key. partial modifier_keys xkb_symbols "menu" {     key  { [ Menu ] }; };   to that   // Menu is mapped to the Menu key. partial modifier_keys xkb_symbols "menu" {     key  { [ Control_R ] }; };   and then logged in again, but unfortunately it does not work.  How is this done correctly?


How to use the comparison test with a series whose terms are given by a rational function?

What is the proper way to find $B_n$ using the comparison test, do I have to compare $A_n$ to the largest term on the numerator/denominator?     Ex. $A_n:\sum\frac n{n^2-1}$ diverges.   If I compare $A_n:\sum\frac n{n^2-1}$ to $B_n = 1 / n^2$ then $A_n > B_n$  which means if $B_n$ diverges then $A_n$ will diverge (Does not Diverge)?  If I compare $A_n:\sum\frac n{n^2-1}$ to $B_n = n / n^2$ then $A_n > B_n$ which means if $B_n$ diverges then $A_n$ will diverge (correct as $B_n$ diverges)  If the proper method is to take highest term on numerator / denominator of $A_n$ to use as $B_n$ then why do I often see solutions where this is not the case?  Ex.   Ex.


Trigger to check for duplicate contacts on lead conversion

I'd like to write a Lead trigger, to check for duplicate Contacts before inserting the lead, or converting it.   Contacts fields I'd like to check:   Firstname - should not be the same as the leads name Lastname - should not be the same as the leads name Email - should not be the same as the leads phone   After checking these fields & failing to find a duplicate, only then should the lead be converted.


I got a old desktop SMPS rated 250watts. In the output panel its written as, it can supply  a output of 12v16amp. So my question is, it is possible to supply a steady 12v3amps from a 12v16amp smps. I also checked connecting my motor with the smps but the motor rotated for just 2 seconds and turned off automatically.  Thanks!


Why in C++ a method from base class is called even the method is overrided while iterating through a list

Why the virtual makeNoise method of the base class is called instead of the method of the inherited class when I iterate through the list of Animal objects in following code. If I call directly the makeNoise method from the inherited objects then the right out put is printed out.  #include <iostream> #include <list>  class Animal { public:   Animal() {   }   virtual ~Animal() {   }    virtual void makeNoise() {     std::cout << "This animal makes no sound." << std::endl;   } };  class Dog: public Animal { public:   virtual void makeNoise() {     std::cout << "Wuf!" << std::endl;   } };  class Cat: public Animal { public:   virtual void makeNoise() {     std::cout << "Maouw!" << std::endl;   } };  int main() {   std::list<Animal> listOfAnimals;   Animal * cat = new Cat();   Animal * dog = new Dog();   listOfAnimals.push_back(*cat);   listOfAnimals.push_back(*dog);    for (std::list<Animal>::iterator it = listOfAnimals.begin();       it != listOfAnimals.end(); ++it) {     it->makeNoise();   }    cat->makeNoise();   dog->makeNoise();    return 0; }   The output looks like:  This animal makes no sound. This animal makes no sound. Maouw! Wuf!   I would expect the noises of Cat and Dog to be printed out also while iterating. That is the functionality of virtual method as I would understand it. Does the type definition of the list affect it somehow?


How can I delete folder named C: inside the E:/ drive?

Can anyone help me figure out how could I delete this folder named C: that was in a game folder. I tried deleting using FileShredder, and this created another series of folders that end up in a folder named C: that I cannot delete, acces or do anything with. I am using Windows 8.1     Solved by using Chckdisk utility.


I have to write a newenvironment, which plots a grey box around the text.   I can't decide which package I should be use. I am writing a dissertation and I want that some text sections have a grey box around the text.   Which package should I use for my newenvironment{greyBox}?  So you see down newenvironment it produces grey box around my text, but I want use this one  \vspace{5mm} \begingroup \leftskip4em \rightskip\leftskip\textit{``text here.''} \vspace{5mm} \endgroup   in my newenvironment, but i can't integrate into it. The text in newenvironment should to intend right and left.   \documentclass{book} \usepackage[ngerman]{babel}  \usepackage{xcolor} \usepackage{mdframed}  \newenvironment{bla}%   {\begin{mdframed}[backgroundcolor=lightgray]}%   {\end{mdframed}}    %%%%%%%%%%%%%%%%%%%  \begin{document}  \begin{bla}  \begin{itemize}   \item Beccari   \item Gregorio   \item Blue    \end{itemize} \end{bla}  \end{document}   I want exactly, that text + box are centered.   I want like this picture   Only the red part should be have a grey box, but I don't find still yet a solution.


What happens when an invisible creature is detected?

From the PHB, Appendix A on Conditions:  INVISIBLE  An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding, the creature is heavily obscured. The creature's location can be detected by any noise it makes or any tracks it leaves. Attack rolls against the creature have disadvantage, and the creature's attack rolls have advantage.   One of my players was sneaking around while invisible. Unfortunately, his Stealth roll failed to beat an NPC's Passive Perception, so he was detected. What does 'detected' actually mean? I ruled at the time that the NPC could tell someone was there but not exactly where (because she heard the noise made by someone moving), but RAW, did she know exactly where he was?


I want to add two JSON objects which have structure like this (It has more data and I ignore them in here):  { "total_count":100 , "types":20 , { "a" : 5 , "b" : 6 }}  {"total_count" : 1 , { "a" : 2 } }   I want to add these objects in node.js in order to get following object:   { "total_count":101 , "types":20 , { "a" : 7 , "b" : 6 }}   I use mongodb which has $inc function which add current json to existing one in db and reduce load and store load. I'm interested to find a method which handle this action in nodejs.What should I do ( I dont want to do it manually preferly. instead i like to use existing functions)?


Evalutating $\lim_{x\to +\infty} \sqrt{x^2+4x+1} -x$

I'm looking to evaluate  $$\lim_{x\to +\infty} \sqrt{x^2+4x+1} -x$$   The answer in the book is $2$. How do I simply evaluate this problem?   I usually solve limits such as this with the short cut method, i.e (Numerator degree < Denominator degree) = 0 ; (Numerator degree = Denominator degree )= take ratio of leading coefficients; (Degree numerator > degree denominator )= take leading terms and use algebra to simplify and then plug in $-\infty$ or $+\infty$ Please keep in mind that I do not know L'Hopital's rule.


How to mount PCIe SSD from MacBook Air in another computer

I got this SSD out of an Apple laptop that's broken from liquid damage.  What is this connection called and how do I mount this storage device to retrieve data from it? It looks like PCIe. Does Apple sell a part to mount this via USB adapter or something?


"Polish l" in bibliography using sharelatex

I am using sharelatex with a separate bibliography file. Some of the authors cited use a lowercase Polish l in there name. The LaTeX code for this symbol is \l{}. Here is a typical entry:   @article{123, AUTHOR = {Karo\'{n}ski, Micha\l{} and \L{}uczak, Tomasz and Thomason, Andrew},...}   However, sharelatex keeps interpreting the \l{} as an incomplete math symbol (according to the compiler error) and is not producing proper output in my bibliography. Here is the compiler error:  <inserted text>                  $ l.99 Alan Frieze and Micha\l                             {} Karo\'nski. I've inserted a begin-math/end-math symbol since I think you left one out. Proceed, with fingers crossed.    BTW, \L{} and \'{n} both work just fine, along with all other foreign accents in names and titles in my bibliography, but the \l{} looks like \ell and everything after \l{} is in math mode.  Any ideas on work arounds out there?


Monitoring traffice from an internet enabled printer

I have a WiFi internet enabled printer that can grab content from the web. I want to use something like Fiddler or Wireshark to view the traffic it's sending and receiving. Is possible? How would I go about accomplishing this?


How can I get Ubuntu to work with Radeon R9 390?

I am running 17.10, and struggling to get my graphics card working. The GUI continues to have graphical artefacts  and screen tearing. Worst of all after a few minutes the GUI crashes and the screen turns black. I have followed several sets of instructions designed to fix problems for Radeon Hawaii cards and none have had ANY impact on the issues.  I have:   disabled radeon and used amdgpu driver instead. switched from display port to hdmi. tried other kernels.   Here is the output of lspci -k  01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Hawaii PRO [Radeon R9 290/390] (rev 80)     Subsystem: XFX Pine Group Inc. Hawaii PRO [Radeon R9 290/390]     Kernel driver in use: amdgpu     Kernel modules: radeon, amdgpu   I have tried various solutions from questions like these .  Should I give up on Ubuntu (or Linux in general), or is there an effective way to get this card working?


I had a interview on deep learning internship job yesterday, and the interviewer showed a loss function formula(below) and asked me 2 questions:  \begin{equation} J(\theta)=-\mathbb{E}_{x,y\sim\hat{p}_{data}}\log{p_{model}(y|x)} \end{equation}   How to understand $p(y|x)$ in the formula above? On what task does this loss function used for?   Since I have no idea on this loss function, how to answer these 2 questions?


Is there any perfect squares that are also binomial coefficients?

Examining the Tartaglia's triangle, I have observed that all the squares were the trivial cases, that is, $\binom{n^2}1$ or $\binom{n^2}{n^2-1}$.  More formally:  Conjecture: If $\binom nm=k^2$ then $n=k^2$.  Is it known to be true?  I have tried to use the formula  $$\nu_p\left(m!\right)=\sum_{k=1}^\infty\left\lfloor \frac m{p^\alpha}\right\rfloor$$  to prove that the exponents of the factorization of the binomial coefficients are odd, but I realized that this cannot be proved, because the binomial coefficients needn't be square-free: $\binom 63=20$, for example.  Any ideas?


Who originated the terminology "Dark Lord of the Sith"?

The Sith were not mentioned in the theatrical versions of the original Star Wars trilogy.  However, Darth Vader was identified as "a Dark Lord of the Sith" as he made his first appearance in the novelization (officially authored by George Lucas, but actually ghostwritten by Alan Dean Foster).  It also seems to imply that Vader's masked, mechanical appearance may not be unique to him, but may be instead be shared by all the Sith.  So who came up with the name "Sith," Lucas or Foster (or someone else)?  And what was "Sith" conceived of meaning, when they were first named, ca. 1976?


I want to check whether a user contains a certain public group. I have tried the following select statement  [SELECT id, Name FROM Group where RelatedId=: userInfo.getUserRoleId() and DeveloperName  = *`<public group name>`* Limit 1]   But this does not return any record even though I have assigned the user into the public group.


Lubuntu Wireless Driver for BCM4309 [14e4:4324] (rev 02)

I have installed Lubuntu on an old Dell D600 laptop. Everything is working great except for the wireless Ethernet card.  "lspci -vnn -d 14e4:" reveals the following:  ~~~~~  Broadcom Corporation BCM4309 802.11abg Wireless Network Controller [14e4:4324] (rev 02)  ~~~~~  Somebody recently (Sept 5th) posted the answer for a card very similar to this (all the same except for the "rev 02" part) - and in their answer they stated something similar to "You have a 50% chance of having the other (rev 02) version of this wireless card - if it turns out you have that one, post back again for recommendations relevant to that".  Apparently the other question-asker did not have the "rev 02" version, as they did not post back again.  I'm hoping either the person posting that answer or somebody else here could post their recommendations for the "rev 02" version of this card.  Regards.


What to fill under occupation if you have quit your job

I have worked as a Software Engineer for around 4 years, but I do not have a permanent job right now (aside from some freelance work). My passport says my profession is Software Engineer.  I am visiting Germany for a job interview. I have the required documents from the company interviewing me.  In the visa application form, under occupation, should I choose No Occupation, or should I choose an occupation (Software Engineer is not listed. The closest I can find is 'Computer Expert'). If I do choose an occupation should I keep the Employer's Name blank or should I put N/A?   is a link to the application form for your reference.


Is it wise to buy indexed whole life insurance?   I am evaluating an option that limits upside at 10% per year  with no down side.  I am Currently 55 and in good health with about 10 years left to work.


I work for a company that owns agricultural land. Our new project is consolidating the small plots we own by swapping with other owners. We have a village were we managed to find all big owners and to map all our plots. All the owners have plots dispersed all over the village. We want to find or design an algorithm to optimally swap land plots between us and other owners in order to best consolidate.  Is there such a tool in QGIS?


How do we see? Where do the photons disappear?

I know that the light is reflected from a object to my eyes, but I don't understand exactly how. The photons appear from the light source and disappear in my eye! Can someone explain the phenomenon of where the photons go and do to allow us to see?


OpenGL: What's the best way to convert a screen coordinate to a world coordinate?

For example, suppose I'm building a first-person shooter and the player pulls the trigger. I want to convert the screen coordinate (x, y) into a world coordinate (x, y, z) to know what they've hit.  I've seen some people mentioning a lookup using glReadPixels, but I've heard it's slow and those references were years old, so I'm not sure if this is the best way.  I'm working with core OpenGL 3.3, not ES. gluUnProject is not part of the API I'm asking about.  These types of answers would be most helpful:   An explanation of how to retrive a pixel's (x, y, z) value using glReadPixels and how to transform that into world coordinates. I know how to multiply by inverse matrices; I don't know exactly what steps OpenGL takes to arrive at its depth buffer value. Or, an explantion of how to do something similar, perhaps more efficiently, with a pixel buffer object. Or some method that I don't even know about that's better than either of the above.   For some context: I have many months' worth of code into a game I'm developing in OpenGL using the core 3.3 profile. I'm using minimal libraries and not the old fixed-function GL pipeline, which is why it does not make sense for me to use gluUnProject. I mention this to highlight why this question is not the duplicate of a currently-linked older question.  Note: I previously mentioned a shader idea that did not add much to the question, so I removed it. I also edited the question to clarify the context and the type of answer I am looking for.


When creating an android game for example space invaders. How big would the sprites have to be? The Enemy ships and player ship and boss ships. So they fit on the android phone and is playable. I'm confused between resolution and this.    Thanks.


I need determine the maximum number of squares  of the given size that can be packed into a circle of the given radius. Squares can  be rotated. I'm not sure how complex this problem is and i can find little about it on the other sites.


What are electrons holes and how they differ from free electrons?

So I'm confused about electrons holes and how they differ from free electrons. I have this question in my mind for months and I couldn't any solid answer.


Can any player character features alter the base stats of weapons?

Some spells, like  and , change base stats of weapons. Are there any player character features that are not spells that alter the base stats of weapons?     Stats being any properties, Damage die size/type, magical or not, +1 +2 +3 etc.  I'm not asking to solve any particular problem, just out of curiosity.  I'm not looking for a list of all the effects that do so, just a simple yes/no backed up with at least one example. I'm looking for RAW and official examples. Please no UA.


Testfor specific items in player's offhand

How can I use /testfor to see if a player is holding a bow with the name "Crossbow" and lore "It is powerful" in his offhand?


While reading the next and previous lines in a file I get a null pointer exception

I know the way to read the next and previous lines while reading a file line by line is like  String prev = null; String curr = null; String next = null;  Scanner sc = new Scanner(new File("thefile.txt"));  while(sc.hasNextLine()) {     prev = curr;     curr = next;     next = sc.nextLine();   But during the first iteration I get a null pointer exception as I have to work with the current element.  Whats the workaround for this?      Scanner sc = new Scanner(file);      String curr = null ;     String next = null ;         while (sc.hasNextLine()) {              curr = next;             next =  sc.nextLine();             if(curr.length() > 0 && !curr.equals(". O O")) {                 lines+= curr.substring(0, curr.indexOf(" ")) + " ";                  for(String pat : patStrings)                 {                 // System.out.println(pat) ;                     Pattern minExp = Pattern.compile (pat);                     Matcher minM = minExp.matcher(curr);                     while(minM.find())                     {                         String nerType = minM.group(2);                         if(nerType.contains("B-NE_ORG")){                             if (next.contains("I-NE_ORG"))                                 orgName+= minM.group(1)+" ";


Shell script zips a folder, but exclude parameters not working IF its run from cron.daily

The script works fine if I run it with sh filename, but it ignores all the --exclude parameters if its run by cron:  #!/bin/sh TIMESTAMP=$(date +%u)  WEEK=`date +"%V"` if [ $(($WEEK%2)) -eq 0 ]; then     echo "even";     BACKUP_DIR="/mnt/backup/2_$TIMESTAMP"     mkdir -p "$BACKUP_DIR/www"  else     echo "odd";     BACKUP_DIR="/mnt/backup/1_$TIMESTAMP"     mkdir -p "$BACKUP_DIR/www"   fi  if [ $(date +%u) -gt 6 ]; then     zip -r -y $BACKUP_DIR/www/web.zip /var/www/ --exclude='var/www/\.opcache/*' --exclude='var/www/utils/phpThumb/cache/*' else     zip -r -y $BACKUP_DIR/www/web.zip /var/www/ --exclude='var/www/mycompany/files/*' --exclude='var/www/\.opcache/*' --exclude='var/www/mycompany/szamlazz/xml_szamlak/*' --exclude='var/www/mycompany/files_admin/szamlazz/*' --exclude='var/www/mycompany/files_admin/chatFiles/*' --exclude='var/www/mycompany/utils/phpThumb/cache/*' --exclude='*/backup-guard/*' --exclude='var/www/mycompany/mailer/*' --exclude='var/www/mycompany/attachments/*' fi  exit 0   The above script should create a larger backup on sunday, and a partial on weekdays, but it just zips everything.


Complete valuation field has no other valuations

Let $K$ be a complete discrete valuation field. That is, suppose that $K$ is a field, and that there is a map $\nu : K^{\times} \rightarrow \mathbb{Z}$ such that $\nu(a+ b) \geq \nu(a) \vee \nu(b)$, $\nu(1) = 0$, and $\nu(ab) = \nu(a) + \nu(b)$. How might I show that there are no other valuations on this field? For instance, when we complete $\mathbb{Q}$ to $\mathbb{Q}_p$, the other valuations $\nu_q$ disappear for $q \neq p$.


How to write system of differential equations

I need help in writing this system in LaTeX:       EDIT: I need more help because I am still unable to use the provided solution. My system is:  \begin{empheq}[left=\empheqlbrace]{align} \begin{eqnarray}     \begin{rcases}     \frac{d\phi_{1}(t)}{dt}&= -\phi_{1}(t)-c_{1}\phi_{3}(t),\\     \frac{d\phi_{2}(t)}{dt}&= \alpha_{1}\phi_{3}(t)-(d_{1}+\mu_{1})\phi_{2}(t),\\ \nonumber     \frac{d\phi_{3}(t)}{dt}&= \mu_{1}\phi_{2}(t)-d_1 \phi_{3}(t)-c_{2}\phi_3(t) \tilde{z_2}(t),\\ \nonumber     \frac{d\phi_{4}(t)}{dt}&= \alpha_{2}\phi_{3}(t)\tilde{z_2}(t)-(d_2 + \mu_2) \phi_{4}(t),\\ \nonumber     \frac{d\phi_{5}(t)}{dt}&= \mu_{2}\phi_{4}(t)-d_{2}\phi_{5}(t),\\ \nonumber     \end{rcases} \end{eqnarray} \\ \begin{eqnarray}     \begin{rcases}             \phi_{1}(t^+)&=\phi_{1}(t),\nonumber \\             \phi_{2}(t^+)&=\phi_{2}(t),\nonumber \\             \phi_{3}(t^+)&=(1-\delta) \phi_{3}(t),\nonumber \\             \phi_{4}(t^+)&=\phi_{4}(t),\nonumber \\             \phi_{5}(t^+)&=\phi_{5}(t).\nonumber             \end{rcases} \end{eqnarray} \end{empheq}


Getting "Null Object Reference" While Trying Encapsulation

It's probably stupidly simple, but I can't seem to figure out what's wrong. I'm trying to create a demo for showcasing Encapsulation.  Encapsulation.class:  public class Encapsulation { // 'numberOfEggs' is an instance variable // it was made 'private', because we do NOT want it to be directly accessed by other classes // being 'private' also means that only code within the class can read or write its value private int numberOfEggs = 10;  // getter public int getNumberOfEggs() {     return numberOfEggs; }  // setter public void setNumberOfEggs(int numberOfEggs) {     if (numberOfEggs > 0) {         // we used the 'this' keyword to differentiate between the method parameter 'currentNumberOfEggs' and         //  the instance variable 'currentNumberOfEggs'         this.numberOfEggs = numberOfEggs;     } } }   MainActivity.class:  public class MainActivity extends AppCompatActivity {  TextView defaultNumberOfEggs; Encapsulation encapsulation;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);      defaultNumberOfEggs = (TextView) findViewById(R.id.default_number_of_eggs);     defaultNumberOfEggs.setText(encapsulation.getNumberOfEggs()); } }   activity_main.xml:  <RelativeLayout android:id="@+id/activity_main" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.example.vladp.studyandroid1.MainActivity">  <TextView     android:id="@+id/default_number_of_eggs"     android:layout_width="wrap_content"     android:layout_height="wrap_content" /> </RelativeLayout>   And I get a "null object reference" error, when starting the app and setting the text via defaultNumberOfEggs.setText(encapsulation.getNumberOfEggs());, which should display "10" (without the quotation marks).


Confusion on Bid vs. Ask and Spread; Profits

Stock A has a bid price of $100.08, an ask price of $100.10 and a last trade price of $100.  I take that to mean that if I buy the stock at $100.10 then I will have lost a total of two cents. How does a person make a profit when buying and selling stock?  Do I wait until the bid price is higher than the ask price that I paid? I hope that I don't confuse anybody because I'm pretty confused myself.


Aspects of html and possible pdf responses to them

The "scroll", the unending page of HTML, not "broken" up into fixed pages.   Could this be mimicked by manipulating the \pdfpageheight, a pdfTeX primitive and \vsize to set the length of the text, and the page it figures on as a single page including the full length of the text.  Memory limits TeX/pdfTeX limits, viewer limits?  Setting the viewer padding between pages to 0pt would then give the appearance of an "HTML" page, the better id as to browsing a longer text on screen. PDF on screen where most of the searching and associative reading is done waists a considerable percentage of vertical real estate.   Preserving the advantages of the pdf format. A single long page would reserve the off-line viewing, on screen, without any disadvantage.   Generally text for printing and viewing on screen has different requirements anyhow, many other aspects, colors, papersize (printed book formats are multiple, for one, so a source manipulation is mostly required regardless when 'for printing' is meant).  Currently the PDF output and underneath the eventual pdfTeXed source is solved on a per physical dimensions basis, at least near exact geometry of the screen meant to be used, say 16-9 proportionality for most laptop-desktops, so a browsing on page per page is possible. That of course depends not only on the processing of pdf but also on the viewer interplay.  pdfTeX should have more precise instructions possibilities (as conditionals relative to geometry and size to advise the viewer how to output the pdf). XeTeX and LuaTeX are not more finegrained as far as we know.  Ultimately the biggest advantage of PDF is to control how to present the sum of text and graphics and pictures, (audio and video are gadgets mostly), as compared to HTML, where pages are modulated and manipulated with anything by any intermediate interference. Secondly html is almost never a "contained" single file as a PDF file is.  The concept of pages, a separation of pages and the algorithms of TeX and pdfTeX operating and taking into account pages ... waists quite some real estate onscreen. Just a conceptual ruminance, that inspired the question of whether it is technically even feasible to do anything different.  Part of the solution of course is to have a physical monitor that allows for twisting it long side up. It is then that the ordinary pdf (a4), zoomed to convenience shows how much space is wasted. Foot-lines, indexes, title pages, blank pages, that have their reasoned functionality in print, to scan a book, to orient, anotate etc. have little when viewing is on-screen. On screen, and anybody else has probably different modes and techniques, a simple "/ regexed-string" would walk to the appropriate places one is looking for faster and after a possible second or third ajusting of the regeluar expression one should be unbeaten in efficiency per file. So PDF needs links, pdftex calls them "all sorts of annotations", and that should have prevalence when not printing but on screen purpose is meant.  Academia is mostly done searching, and manipulating digital data, no serious research can longer be done based on mostly analog sources. The time frames and the human processor capacity is simply dwarfed as to the variables.  Above to partly justify my question on the technicalities of pdfTeX/XeTeX/LuaTeX to have any justification.  The question repeated: are "very" long pages, a single page per file possible in pdfTeX?


traceroute gives only stars + how to fix

When I do:    $ traceroute 8.8.8.8   I get in the output showing only stars, even though pinging to google.com ( 8.8.8.8) appears to be working.   What do I need to fix in my files/conf in order to solve this issue? what I need to check?    Ping command output      $ ping 8.8.8.8     PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.     64 bytes from 8.8.8.8: icmp_seq=1 ttl=46 time=73.4 ms     64 bytes from 8.8.8.8: icmp_seq=2 ttl=46 time=69.6 ms   traceroute command output   $ traceroute 8.8.8.8  traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets  1  * * *  2  * * *  3  * * *  4  * * *  5  * * *  6  * * *  7  * * *  8  * * *  9  * * *  10  * * *  11  * * *  12  * * *  13  * * *   14  * * *  15  * * *  16  * * *  17  * * *  18  * * *  19  * * *  20  * * *  21  * * *  22  * * *  23  * * *  24  * * *  25  * * *  26  * * *  27  * * *  28  * * *  29  * * *  30  * * *


Is temperature a Lorentz invariant in relativity?

If an observer starts moving at relativistic speeds will he observe the temperature of objects to change as compared to their rest temperatures? Suppose the rest temperature measured is $T$ and the observer starts moving with speed $v$. What will be the new temperature observed by him?


How to prove the closed form of the integral $\int \frac {dx}{\prod_{r=0}^n (x+r)}$

I want to derive a closed formula for the integral $$I_n= \int \frac {dx}{\prod_{r=0}^n (x+r)}$$  On writing out first few terms we get   For $n=0$, $$I_0=\ln \vert x\vert+C$$ For $n=1$, $$I_1=\ln \vert x\vert-\ln \vert x+1\vert+C$$ For $n=2$ $$I_2=\frac {1}{2!}\left(\sum_{r=0}^2 (-1)^r\binom {2}{r} \ln \vert x+r\vert\right)+C$$ For $n=3$ $$I_3=\frac {1}{3!}\left(\sum_{r=0}^3 (-1)^r\binom {3}{r} \ln \vert x+r\vert\right)+C$$  Hence for generalized $n$ we have $$I_n=\frac {1}{n!}\left(\sum_{r=0}^n (-1)^r\binom {n}{r} (\ln \vert x+r\vert)\right)+C$$  Now this is just an observation but I want to prove that it is correct. I have tried lot of methods but not useful. Partial fractions would have been most useful but would go out on tedious task which is nearly impossible.  Also integration by parts won't help nor any trig substitution. So any ideas are welcome.  And ya,  this is not a homework question,  it's a question which I just saw in a integral challenge paper.


Is there any benefit from installing Windows 7 64-bit when you have less than 4GB of RAM?

I've recently purchased Windows 7 Ultimate.  I have an AMD Athlon64 X2 5000+ with 2GB DDR2 RAM.  I know RAM has gotten much cheaper, I know, I know, but I am not going to be able to upgrade my RAM for about a year.  My question is obviously this; will I get any benefit from installing 64-bit Windows over 32-bit if I'm only using 2GB of RAM?    As I understand, the minimum requirement is 2GB & max is 192GB so if the minimum for 64-bit is 2GB & the minimum for 32-bit is 1GB will I lose performance if I chose to install 64-bit at it's minimum requirement over 32-bit whose minimum is half the amount?  I would like to install the 64-bit edition if only because it's the future.  192GB of RAM! that's incredible! Plus I've heard it simply performs better.  But that is with a larger amount of RAM.  I've tried to make this question as easy to decipher as possible.  Any advice would be greatly appreciated.


BibTex fails on opening database "-blx" file

I'm kind of new here. I googled for hours this evening, frustratingly looking for an answer to my problems.  So I compile like this: pdflatex -> bibtex -> pdflatex -> pdflatex -> pdfview I use TexMaker, i have a build folder ,etc etc. I started using a build folder because I saw it being advised to people with similar problems, I didn't have one before.   So my file is test.tex. When i use pdflatex, it creates a test.aux in the /build folder. Following this, bibtex goes to check in this file and sees this:  \relax  \bibstyle{biblatex} \bibdata{test-blx,test}   Then for some strange reason BibTex can't find test-blx.bib  although it is there, it's created by pdflatex. The error i get is this one:  Process started  This is BibTeX, Version 0.99d (MiKTeX 2.9) The top-level auxiliary file: build\test.aux The style file: biblatex.bst I couldn't open database file test-blx.bib ---line 3 of file build\test.aux : \bibdata{test-blx : ,test} I'm skipping whatever remains of this command I found no database files---while reading file build\test.aux Warning--I didn't find a database entry for "biblatex-control" Biblatex version: 3.0 (There were 2 error messages)  Process exited normally   And then i goes further downhill.  The test file i created looks like this:  \documentclass[12pt]{article} \usepackage[style=authoryear,backend=bibtex]{biblatex}  \bibliography{test.bib} \begin{document}  jan piet joris en korneel ze hebben baarden en hipsterstaartjes\nocite{*}  \printbibliography %\bibliographystyle{abbrv} %\bibliography{thesis} \end{document}   Using a different approach (biber,etc) is not a solution to my problem.  Thanks  EDIT: just to make sure: I had the problem before, when i wasn't using a build folder, as well. Bibtex can find the aux file that is created in the build folder without trouble.  EDIT2: so i played around with it some more. recreating my article in a new file seemed to fix the problem, but moving this recreated article to the folder of my original article messed things up again. So right now it seems that placing my .tex files in my dropbox folder (i always work in a cloud environment for safety) will cause bibtex to fail, very strange.


Complex Numbers: How do I prove that the statements $|z+1|>|z−1|$ and Re(z)>0 are equivalent?

I know that $|z + 1|$ represents the distance between $z$ and $-1$ and $|z - 1|$ represents the distance between $z$ and $1$. From here, I can derive that there will be a line $x$ that will be the perpendicular bisector of the line segments joining the points $(-1,0)$ and $(1,0)$. How do I continue from here?


Chronosys - Write events above the timeline

So I have a timeline with events that are very close to eachother, to avoid them overlapping, I would like to write events under and above the timeline in alternance. It seems that by default, events are always written under the timeline... Can someone help me with this?


When I'm Backing Up My Files Using the Backup Application, at the last time it shows a error that     Could Not Backup The Following files make sure you are able to open them  /home/neel/.cache/dconf /home/neel/.dbus


I have cobbled together a command to return the process ID of a running daemon:  ps aux | grep daemon_name | awk "{ print \$2 }"   It works perfectly and returns the PID, but it also returns a second PID which is presumably the process I'm running now. Is there a way I can exclude my command from the list of returned PIDs?  I've tested it a few times and it appears my command is always the second PID in the list, but I don't want to grab just the first PID in case it's inaccurate.


How can we decrypt all RSA messages given a function that can efficiently decrypt a small percentage of all possible ciphertexts?

I saw this question in a paper and was not able to solve it. Assume that we are given an efficient algorithm called RSA_break() that can decrypt, without the knowledge of the private key, 1% of all possible ciphertexts encrypted using the public key (n,e) in RSA. Basically, for a single ciphertext, RSA_break() will deterministically output the entire original plaintext or return a failure. For 1% of the set of all possible ciphertexts, RSA_break() always succeeds, while for the rest 99%, it will always fail. How can I use this RSA_break() function as a building block to build an efficient algorithm to break all possible ciphertexts?


How can we prove that "Every Group of order $216$ contains a normal subgroup of order $27$ or $9$ ?".  MY TRY: $216=2^3.3^3$.So possible order of sylow $3$ subgroup is $1$ or $4$ and similarly for sylow $2$ subgroup is of order $1,3,9\,\text{or}\,27$.Then how to proceed $?$Thank you


How to detect a player right-clicking with an item?

I want to make a "lightning rod" in Minecraft. I'll have a stick or something that when right-clicked, it summons lightning one block in front of player.  How can I detect a player right-clicking with a specific item in hand?


Auto comment "possible duplicate of ..." missing on voting to close as duplicate

Please refer to the following question:    The  had posted an  a while back.  I posted a comment referring to the same and voted to close the question as a duplicate of the referenced question.  Surprisingly, an auto comment saying "possible duplicate of ..." was not generated.  I agree that the referenced question shows up in the linked questions list but an auto comment ought to be generated.  Seems like a bug.    EDIT: I understand that the above behavior is by-design.  However, I'd say that the behavior in the following case should also be the same:  It's interesting to see that the auto comment would be generated if you were to add a comment linking to an answer and then voting to close the question as duplicate.  For example, observe the following question:


How to recover/restore corrupted Innodb data files?

A while ago, my Windows 7 system on which a MySQL Server 5.5.31 was running crashed and corrupted the InnoDB database. The weekly backup that's available does not cover all the tables that were created in the meantime, therefore I would endeavor to recover as much as possible from the data. Right after the crash, I copied the whole data folder of MySQL to an external drive. I would like use this as the starting point for my rescue attempts.    In the following I'll describe the steps of my (not yet convincing) rescue attempt so and would be thankful for any comments or guidance on how to improve it:     I've now done a fresh install of MySQL Server 5.5.31 on another PC   I stop the MySQL service with "net stop MySQL" at the command prompt.   I already figured that I need to adjust the size of the innodb log file in the my.ini file as it deviates (256 MB) from the default value (19MB).   In the my.ini, I also set innodb_force_recovery=6   In the data folder of the fresh installation, I overwrite the ibdata1, iblogfile0, iblogfile1 files with those recovered from the crashed machine. I also copy the relevant database (UPDATE: and the mysql) folders into here (NOT the standard mysql, test and performance folders).   I start the MySQL service with "net start MySQL".   I go into MySQL Workbench, open my server instance, go to Data Export, basically leave the default settings, and have every table of my databases exported as an individual dump file. I also set stored procedures to be dumped. Otherwise I do not change the default settings there.   I start the dump process; it makes its way through 43 out of 195 tables. Of these 43,  some cannot be recovered yielding an error "mysqldump: Got error: 1146: Table '...whatever...' doesn't exist when doing LOCK TABLES",   but many can. I assume that when the dump does not yield any error, the table's data is non-corrupted. Then, after the 44th, all the other table dumps fail as it is reported that the server cannot be connected to anymore: "mysqldump: Got error: 2003: Can't connect to MySQL server on 'localhost' (10061) when trying to connect Operation failed with exitcode 2" These errors then go on for all the remaining tables from the 44th to the 195th. For the 44th table itself, the error is the following: "mysqldump: Error 2013: Lost connection to MySQL server during query when dumping table ...table 44... at row: 57". So it seems that for this table corruption is or begins at row 57.    Now to my questions:     Why is the connection breaking down given that innodb_force_recovery is set to 6? How to proceed? I worked out what the 44th table was where the connection was lost and can try to resume the process from the 45th table. But isn't there a better way to do it? Once the data has been copied and the server restarts well, should I just try a dump of each table or what alternatives are there?     Thanks.    UPDATE: Additional notes for my later reference - When re-creating stored routines backed up using SHOW CREATE PROCEDURE ... and SHOW CREATE FUNCTION ..., they must be imported using  DELIMITER // (create procedure code of procedure 1)// (create procedure code of procedure 2)// DELIMITER ;


I often see sentences like     We are interested in predicting whether an individual will default on his or her credit        card   or      Activate only when your opponent adds a card to his or her hand   Why are people using "his or her"? Would it be correct to replace "his or her" with "their"? For example     We are interested in predicting whether an individual will default on their credit card   This seems like it says the same as the first sentence, but I never see it used.


I'm writing a set of course notes that has an appendix containing many activities.   I do not wish the activities to be shown in the Table of Contents, but I do wish them to be numbered. Here is the solution I was using:  In the preamble:  \newcommand{\activity}[2]{\bgroup\let\addcontentsline=\nocontentsline#1{#2}\egroup}   and now my "activity" starts out with:  \newpage \activity\section{A Fun Educational Activity}   There is only one problem. The activity starts out indented, as opposed to not indented, as a section should be.   How do I make my activity start out without an indent?  I realize I could simply add \noindent but it seems to me that there should be a more elegant solution.


Finding the probability that the matrix has full rank

There are only two entries, $0$ and $1$, over $\mathbb{Z}_2$. Thus,   only $16$ possible $2\times 2$ matrices over $Z_2$, and $6$ of them   have full rank:      $\begin{pmatrix}0&1\\   1&0\end{pmatrix}  \quad \begin{pmatrix}1&1\\   > 1&0\end{pmatrix}  \quad \begin{pmatrix}0&1\\   1&0\end{pmatrix}  \quad > \begin{pmatrix}0&1\\   1&1\end{pmatrix}  \quad \begin{pmatrix}1&1\\   > 0&1\end{pmatrix}  \quad \begin{pmatrix}1&0\\   0&1\end{pmatrix}$      Randomly generate a $n\times n$ matrix over $\mathbb {Z}_2$ (where n   is big, say, $1000$). What's the probability that the matrix has full   rank?   I'd want to talk something regarding to this question.   I found the probability is equal to:  $\dfrac{(2^n-1)(2^n-2)(2^n-2^2)...(2^n-2^{n-1})}{2^n} \tag{1}$  On other hand, what's difference between $2^n$ and $2^{n^2}$?  $\dfrac{(2^n-1)(2^n-2)(2^n-2^2)...(2^n-2^{n-1})}{2^{n^2}} \tag{2}$  Can you tell whether or not I'm wrong?   Regards!


What is a good Hash function? I saw a lot of hash function and applications in my data structures courses in college, but I mostly got that it's pretty hard to make a good hash function. As a rule of thumb to avoid collisions my professor said that:  function Hash(key)   return key mod PrimeNumber end   (mod is the % operator in C and similar languages)  with the prime number to be the size of the hash table. I get that is a somewhat good function to avoid collisions and a fast one, but how can I make a better one? Is there better hash functions for string keys against numeric keys?


Early 2010s animated TV show about magic dice

This was an animated show with teenage characters from the early 2010s. It was more on the childish side I guess, and I specifically remember it having to do with magic dice that when you rolled it like a magic affect would happen.


How can I tell how many Cores SQL Server is actually using?

I have two servers running SQL Server.   Server 1: SQL Server 2008 R2 Express (4 core) Server 2: SQL Server 2012 Developer Edition (8 core)   As far as I am aware SQL Server 2008 R2 Express should only use one core.  SQL Server 2012 Developer version should use all 8 cores.  However if I run the following command inside of SQL query on SQL Server 2008 R2 Express it's showing 4 cores.  select scheduler_id, cpu_id, status, is_online  from sys.dm_os_schedulers  where status = 'VISIBLE ONLINE'   Am I using the right command to gauge the usage?


Are all Gallifreyans able to regenerate?

I saw in an question that Susan Foreman might not be a Time Lady. This made me think if she would regenerate like the Doctor. Are all people from Gallifrey Time Lords? I remember an episode where there were people who seemed to live outside of the Time Lord world. Do they all regenerate?