I was thinking earlier about air bubbles in water. if you had a bubble of air (say in a balloon) then as you take it down in water the bubble shrinks because of the pressure and because it is compressible. This means its density increases.  Water on the other hand being incompressible remains the same density at whatever depth you are at (I don't know if it is truly incompressible but I am assuming if it is at all compressible this is insignificant).  Does this mean that there is a depth at which an air bubble would be denser than the surrounding water and thus sink instead of float?  Would the gas at this density be doing things like turning into a liquid? Is the depth such that this is not even vaguely realistic? I feel like the situation is probably a lot more complicated than it is in my head which says that you would get air bubbles sinking at sufficient depth?


Regex Help- Escaping Characters And Matcher Method

I have a string:   allPunctuation = '~!@#$%^*()_+|}{":?><`=;/.,][-\'\\';   This string contains APEX's way of escaping characters so I can include the ' and the \ characters.   When I pass this string into the replaceAll() method I get back an error because the escape characters are not carried over and the regex needs the escape characters. Is there a way around this?  ie: when I system.debug allPunctuation I get back: ~!@#$%^*()_+|}{":?><`=;/.,][-'\ This clearly doesn't have the escape characters anymore.   My second thought was to utilize the matcher method. Documentation found here:    I am not sure why, but it is returning back a false. To me it seems like it shouldn't be affected by the escape quotes. And legalName has all sorts of punctuation in it.   Pattern NonAlphanumeric = Pattern.compile('[^a-zA-Z0-9 ]'); Matcher matcher = NonAlphanumeric.matcher(legalName); //system.debug(matcher) ---> false   Could someone point me in the right direction?


Why is a particles potential energy minimal (not zero) when the forces acting on it equal zero?

I have the two following graphs representing a particles potential energy in function of its distance to another particle and another one which represents the attraction and repulsion forces between two particles with respect to their intermolecular distance.    As you can see $E_p$ is minimal when $F=0$. However potentially energy (as I know it) is given by $E_p = -\int \vec{F}.d\vec{r}$. So if F=0 this multiplication should clearly result in 0, but it doesn't. Why?  PS: follow-up question: knowing that $\frac{-dU}{dx} = F(x)$. I cannot see this relationship between the two graphs,i.e. completely on the left of the $E_p$,r - graph, you can clearly see the curve has a negative slope. Meaning the derivative should be negative, however this is not what is being shown on the lower graph. The only "correct" thing I see is that when the slope of the upper graph is 0 (at $r_0$)the derivative indicates that correctly.  Do I read the graphs incorrectly?


My primary partition is running out of storage so I scanned my system for files larger than 50MBs using sudo find / -type f -size +50M -exec du -h {} \; | sort -n  and I got 3.4G    /var/log/user.log 3.5G    /var/log/messages 3.8G    /var/log/syslog 57M     /var/log/journal/979a37e4ed2a4f8bb22add990526b81f/user-1000@0005ac085c8d7ba9-cf9aa9ed29211912.journal~ 57M     /var/log/journal/979a37e4ed2a4f8bb22add990526b81f/user-1000@0005ac762fd0c667-79d328077f2a1441.journal~ 129M    /var/log/journal/979a37e4ed2a4f8bb22add990526b81f/user-1000@eab408d6ed9a489f80204676d10dcc8f-00000000000c0054-0005ac611037d27c.journal 129M    /var/log/journal/979a37e4ed2a4f8bb22add990526b81f/user-1000@eab408d6ed9a489f80204676d10dcc8f-00000000000e0084-0005ac6150518d34.journal 129M    /var/log/journal/979a37e4ed2a4f8bb22add990526b81f/user-1000@eab408d6ed9a489f80204676d10dcc8f-00000000000ffe05-0005ac617074d3a6.journal    152M    /var/log/kern.log     208M    /var/log/daemon.log 222M    /var/log/apache2/error.log  Is it safe to delete all the .log and .journal files?


Touch pad not detected correctly - Asus X540SA

ASUS X540SA, Ubuntu 16.04.1 LTS, Kernal 4.4.0-36-generic  The touchpad seems to be detected as a mouse instead of a touchpad. The touchpad is recognized as a "pointer" rather than a touchpad. It has the basic usability of a mouse, with no ability to use multiple fingers or touch scrolling. Along with this, the mouse moves whenever I try to click with my thumb, due to the touchpad registering my thumb as a mouse movement as well. It is extremely difficult to right click because of this as well.  laptop@laptop-X540SA:~$ xinput ⎡ Virtual core pointer                          id=2    [master pointer  (3)] ⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)] ⎜   ↳ FTE1001:00 0B05:0101                      id=10   [slave  pointer  (2)]   The touchpad is detected as FTE1001:00 0B05:0101 and there is no "touchpad" setting in my mouse preferences either.  Shown here:    Is this a problem with the kernel or can I fix this manually?


Degree in Philosophy at Mathematics department?

I saw some tesis that, for me, look as paper of Mathematics and, indeed, are from mathematics' department. However, the name of the course is "degree in Philosophy". There is any explanation about it? I would imagine degree in Philosophy something about thinkers sociologics, human theory, etc. Many thanks.


I need some ideas (preferable some tricks) for solving these two problems:     Find the largest number $n$ such that $(2004!)!$ is divisible by   $((n!)!)!$      For which integer $n$ is $2^8 + 2^{11} + 2^n$ a perfect square?   For the second one the suggested solution is like this  : $ 2^8 + 2^{11} + 2^n = ((2^4)^2 + 2\times2^4\times2^6 + (2^ \frac{n}{2})^2 ) \Rightarrow n=12$  But I can't understand the approach,any ideas?


I am 100% new and have 0% experience with Ubuntu. I can safely say I don't know nor understand 90% of the things I've seen and done so far regarding this. I'm using a bootable USB stick to boot this. I'm on Windows 7, if that matters.  I managed to get to the purple screen where they show a keyboard in a circle being equivalent to a man. By pressing a button on my keyboard, it brought me to a language selection menu where I selected my preferred language (English). Now I am at a screen with "ubuntu; Persistent Mode; Live Mode; Install; File Integrity Check; Memory Test" and more buttons ranging from "F1 Help" to "F6 Other Options".  Now here comes the problem. I tried several times (by pressing Enter) on Persistent Mode, Live Mode and Install, and after a black screen with scrolling white things that are too fast to read, my screen turns black with a blue rectangle ticking around reading "Input Not Supported".  Sometimes when I get this screen, pressing Ctrl+Alt+Del reboots the computer, and sometimes it doesn't work and I have to force shutdown the computer by holding the On button.  Also: I tried looking for solutions online, and saw some stuff regarding graphics or something like that, and something about grub. No idea what any of those mean, hence I came here to type out. From all these you should be able to tell how illiterate I am on this matter.  [Another not-so-important problem] I have tried using this on my Asus Laptop (Windows 8), but apparently I had to do some stuff to be able to boot using USB. I managed to find the way to do it online, but after booting using the USB, it doesn't show anything and just starts the laptop like normal.


I want to use a word that means "live life happily and enjoy every second and every moment."


Biblatex: multiple citation numbers all within same bracket with the ieee style

I'm using the ieee style for biblatex and when inserting citations I want     [1,2,6-10]   Right now I'm getting     [1],[2],[6-10].   How can I change this?


How could you evaluate this integral?  $$\int_0^{\pi/2}\frac{\sqrt{\sin x}}{\sqrt{\sin x}\,+\sqrt{\cos x}} \, dx$$  I think the answer is $\pi/4$.


pgfplots: tik labels missing and axis labels are inside plot

I am having major trouble in getting pgfplots to work on my Ubuntu 14 System. I am running the minimum example from  and the result looks like the following.    Does anybody have any idea why this is happening?  according to tex -version I am using TeX 3.1415926 (TeX Live 2013/Debian) and I will also post the part of my logfile that is created by \listfiles below. (btw, I tried various compat=1.x commands, but none of them changed anything)  *File List* article.cls    2007/10/19 v1.4h Standard LaTeX document class   size10.clo    2007/10/19 v1.4h Standard LaTeX file (size option) tikz.sty    2010/10/13 v2.10 (rcs-revision 1.76) pgf.sty    2008/01/15 v2.10 (rcs-revision 1.12) pgfrcs.sty    2010/10/25 v2.10 (rcs-revision 1.24) everyshi.sty    2001/05/15 v3.00 EveryShipout Package (MS) pgfrcs.code.tex pgfcore.sty    2010/04/11 v2.10 (rcs-revision 1.7) graphicx.sty    1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR) keyval.sty    1999/03/16 v1.13 key=value parser (DPC) graphics.sty    2009/02/05 v1.0o Standard LaTeX Graphics (DPC,SPQR) trig.sty    1999/03/16 v1.09 sin cos tan (DPC) graphics.cfg    2010/04/23 v1.9 graphics configuration of TeX Live dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR) pgfsys.sty    2010/06/30 v2.10 (rcs-revision 1.37) pgfsys.code.tex pgfsyssoftpath.code.tex    2008/07/18  (rcs-revision 1.7) pgfsysprotocol.code.tex    2006/10/16  (rcs-revision 1.4) xcolor.sty    2007/01/21 v2.11 LaTeX color extensions (UK) color.cfg    2007/01/18 v1.5 color configuration of teTeX/TeXLive pgfcore.code.tex pgfcomp-version-0-65.sty    2007/07/03 v2.10 (rcs-revision 1.7) pgfcomp-version-1-18.sty    2007/07/23 v2.10 (rcs-revision 1.1) pgffor.sty    2010/03/23 v2.10 (rcs-revision 1.18) pgfkeys.sty     pgfkeys.code.tex pgffor.code.tex tikz.code.tex pgfplots.sty    2013/10/03 v1.9 Data Visualization (1.9) ***********


Can I use older screw-type lenses on a Nikon DSLR?

Just purchased a Nikon D3200 DSLR. I have several excellent Pentax (M42) screw mount lenses from my older 35MM.  Is there an adaptor available to allow me to mate those lenses with my new D3200?


While playing Phase Ten, is it legal to pick up the top card of the discard pile and then immediately discard that exact card?


How to highlight a word in the output of "cat"?

I can do the following to see if some word is available in the output of "cat":  cat filename | grep word   This filters the output and shows only those lines which contain "word". Now, is it possible to only highlight the "word" in the output, without dropping other lines?


Subject-verb agreement. Subject is plural, but not really

Once again I have a line that I wrote for another site that has me a bit bugged.     Months in the freezer is going to pretty much eliminate any risk of consuming a live parasite.   Months is obviously plural, but I'm pretty sure that the line is correct as written.  How?  Or potentially, why not?


I would  be pleased if someone could explain to me the participle in this sentence :  James has made a breakthrough in his math this year, doing excellent work in comparison with last year


Setting bash script to be automatically started

When my Mac starts I want to automatically start a batch script called run.sh in the folder myfolder. When I start Automater I only find options for AppleScript and JavaScript.


Hi I have just purchased a second hand Pashley, the serial number appears to be 43742, however, it is difficult to see.  Can anyone tell me if this is a Roadster or a Princess please and would anyone have an idea of the date of the bike. Many thanks.


{$a_n$} $\in N$ .if $(a_m,a_n)=(m,n)$ when $m \ne n$,prove that $a_n=n $ for all $n$

The fact is that I am not getting the question clear if $a_m=5$ and $a_n=17$ and if I take $m=3$ and $n=7$ .This doesn't hold true.Can someone help me to understand what the question is asking me ?


Does anybody know how to achieve a "simple" opacity material in cycles? I'm fully aware of transparent node and mixing it with different shaders, but that's not what I'm looking for, for various reasons.  I'm looking for a diffuse material that treats all the faces it's applied to as a whole, and just simply reduces their opacity like in Photoshop. Below is a rough example of what I'm talking about:    So what's the main difference here is that with transparency node you can see through the faces and also see all the underlying geometry, and I don't want that. (for aesthetic reasons) What I want is a material like on the right, but without the hassle of different renderlayers and compositing.  I guess this might be too much to ask, but I just feel like maybe it could be done with some crazy node setup in cycles?


Pronoun Dilemma - "The winners of the contest were Morgan and me / Morgan and I

In the sentence 'The winners of the contest were Morgan and I', is 'I' or 'me' correct? I think it should be 'I', because 'Morgan and I were the winners of the contest.'


Trouble accessing Ubuntu server with SSH

I purchased a new Ubuntu server several months ago. It is connected to my router. I was able to set up port forwarding for port 22 with my ISP, and then SSH into the server using the internal IP from my Windows laptop using wireless with the same router. I was also able to set up a name for the server and connect it to the external IP address using the No-IP dynamic update service, and was able to access the server using SSH both inside my apartment and remotely.  Then for some reason this stopped working several weeks ago while I was away traveling, and I was no longer able to SSH into the server externally. Since I have been back home I am not able to SSH into it internally either. Nothing has really changed as far as I am aware. I've had several calls with the server manufacturer as well as my ISP, and after troubleshooting all the obvious candidates both sides claim that the issue is on the other end.  I have checked that the IP is correct, port forwarding is set correctly, I've rebooted everything, reinstalled openssh on the server, etc. I have also tried connecting to it from another internet provider. I still can't SSH into the server internally or externally. The server works completely fine, and I can ping it on my laptop, I just can't SSH into it.  edit: I'm using putty with windows for ssh and the error I get is "Network error: Connection timed out"  When I type "sudo systemctl status sshd.service" I get that the system is active (running).  When I type "ssh localhost" I get "WARNING REMOTE HOST IDENTIFICATION HAS CHANGED" and then an error about an offending ECDSA key. "ECDSA host key for local host has changed and you have requested strict checking. Host key verification failed."  edit2: I fixed previous issue with ssh-keygen -R localhost. Now I can ssh into localhost.  I think my question is a little different from this other one  I didn't realize why I wasn't able to connect to ssh and it happened to be that my firewall was enabled. It wasn't that enabling the firewall disconnects a functional ssh connection.


Understanding lack of fit in logistic regression

How does one interpret the fact that a dataset has a poor fit / lack of fit with respect to a logistic regression model? I can make sense, for example, of a lack of fit in the case of a linear regression: the data cannot be modeled linearly. But I can't make sense of a lack of fit for a logistic regression. Do we just mean that there is no S-curve that effectively models the probability distribution of the data (edit per the top comment: log odds of the data)?


Why does TTL sometimes re-increment between DNS queries?

I dig xkcd.com, and I get something like this back:  ; <<>> DiG 9.9.5-3ubuntu0.1-Ubuntu <<>> xkcd.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52538 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5  ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;xkcd.com.          IN  A  ;; ANSWER SECTION: xkcd.com.       769 IN  A   107.6.106.82  ;; AUTHORITY SECTION: xkcd.com.       87784   IN  NS  dns3.p03.nsone.net. xkcd.com.       87784   IN  NS  dns1.p03.nsone.net. xkcd.com.       87784   IN  NS  dns2.p03.nsone.net. xkcd.com.       87784   IN  NS  dns4.p03.nsone.net.  ;; ADDITIONAL SECTION: dns1.p03.nsone.net. 70809   IN  A   198.51.44.3 dns2.p03.nsone.net. 70809   IN  A   198.51.45.3 dns3.p03.nsone.net. 71406   IN  A   198.51.44.67 dns4.p03.nsone.net. 70809   IN  A   198.51.45.67  ;; Query time: 222 msec ;; SERVER: 127.0.1.1#53(127.0.1.1) ;; WHEN: Wed Jan 21 22:16:42 HKT 2015 ;; MSG SIZE  rcvd: 206   The 769 is the cached TTL value for xkcd.com. However, when I do repeat dig xkcd.com several times (within a few seconds of each other), I get a seemingly random TTL value everytime. Here's the sequence:  TRY | ANSWER | AUTHORITY | ADDITIONAL | WHEN ==================================================================== 1   | 586    | 59577     | 44474      | Wed Jan 21 22:18:31 HKT 2015 2   | 587    | 14242     | 56745      | Wed Jan 21 22:18:32 HKT 2015 3   | 658    | 87673     | 70698      | Wed Jan 21 22:18:34 HKT 2015 4   | 1022   | 76200     | 51189      | Wed Jan 21 22:18:40 HKT 2015 5   | 1200   | 160954    | 44662      | Wed Jan 21 22:18:41 HKT 2015 6   | 574    | 59565     | 44462      | Wed Jan 21 22:18:43 HKT 2015 7   | 646    | 87661     | 70686      | Wed Jan 21 22:18:46 HKT 2015 8   | 1200   | 121364    | 55967      | Wed Jan 21 22:18:47 HKT 2015 9   | 1200   | 83292     | 54698      | Wed Jan 21 22:18:48 HKT 2015 10  | 1024   | 40540     | 43816      | Wed Jan 21 22:18:49 HKT 2015   Why do I get this seemingly random (within a range) values for TTL? I expect it to decrease gradually, since it is cached.


How to update Python to the latest version on Ubuntu 18.04

The current version of python I've now which is installed by default with Ubuntu is 2.7rc1 , Is it possible to update it officially to the latest version (3.7.1) ?  Thank You .


Number of points where gravitational field due to $N$ point-masses vanishes

Given $N$ distinct fixed points of equal mass in the plane (eventually, in space), let $f(N)$ denote the number of points $P$ for which the gravitational field at $P$ vanishes.  For example $f(2)=1$ and for $3$ collinear points, $f(3)=3$.   I conjecture that $f(N)$ is finite and nonzero.  Is this true?


How do you become a lich and what happens when you become one?

So I was researching the Book of Vile Darkness. It says in it that it contains the information in which you could become a lich. How would you become one and what happens when you do?


How to access all the public groups relatedto an user in apex

I am trying to find out all the public groups related to an user and display it on a vf page. Is this doable?  Step 1:  from Groupmember I get the group Id related to a user using  list<groupmember> g_m = [select id from groupmember where userorgroupid =: userid];   Step 2: I query all the group info   This gives me only a subset of groups of type ="Regular". How do I access all the Public Groups related to a user.  I also want to display the groups that the user is related to as part of nesting (ie) if user A is related to public group A and public group A is nested within Public group B the user becomes part of Public group B to which I want visibility into .  Any help would be greatly appreciated.


how users will to get ubuntu for phones?

I'm pantech's vega r3 user. This phone matches to highend spec for ubuntu for phone. How you will provide for android phone like this?  Cwm or recovery installable package? Or through OEM or Carrier OTA? I wish more fastly come ubuntu on my phone.  Thanks.


Read committed snapshot:Finding lock on table

IF update command is run on a table and commit is pending then another user cannot be able to update the table.  Is there any query to get the user or PC which caused lock on the table.


Integration of Rational function contain even power of variable $\int\frac{1}{1+x^6}dx$

Evaluation of $\displaystyle \int\frac{1}{1+x^6}dx$   $\bf{My\; Try::}$Let $$I = \int\frac{1}{1+x^6}dx = \int\frac{1}{(1+x^2)(x^4-x^2+1)}dx$$  Using Partial fraction , above Integral is very lengthy, Can we solve it without using   partial fraction or any other way, Help me  Thanks


How did the characters gain their power to perform alchemy in FMA:Brotherhood? Is it genetic, or is it something that can be learned? After all, not everyone in the series can use alchemy.


ModelBuilder Run Time Errors Using ArcGIS 10.0

I recently susccesfully ran a watershed delineation model using both ArcHydro Tools for Arc GIS 10.0 and Model Builder in ArcGIS 10.0 on Windows 7 system (Dell Inspiron N4110 Intel Core TM i3 CPU @ 2.30 GHz 64 Bit.)  However when I try to run the same model on an XP computer (Intel Pentium 4 CPU @ 2.53 GHz 32 Bit) I received several run time errors such as:    Error HRESULT E_FAIL has been returned from a call to a COM component. Fail to execute (Catchment Polygon Processing)" and also other like  Drainage Point.. All the inputs are not current  Adjoint Catchment All the inputs are not current   I try also to build the same model from the scratch in this later system and I received the same type of run time errors.  I'd be pleased to receive any clue to fix this problem.


Regain of reputation from downvoted and deleted answers - update FAQ

I have down voted and flagged two answers as "not an answer." Doing so reduced my reputation by 2 (1 for each down vote). It seemed both of my flags were helpful and both answers were deleted.  As requested, flag screenshot:    As far as I can remember, when a down voted answer got deleted, we got our reputation back.  So I did by manually . You do not have to re-calculate yourself as it will automatically happen at some point.  Rep regain screenshot:    This information is either very hard to find in the  or  or ... or it doesn't exist. It only mentions that you lose 1 rep point for down voting answers, but it doesn't say that you get it back if the answer is deleted. It's commonly known by more experienced users but think about new users, or the ones who are not aware of it...  Let everyone know that voting bad answers is a good thing! That temporary loss of 1 rep point will be given back to you in case the answer is deleted.  Based on the above, I think the FAQ and Help Center should be updated.


Wifi losing connection, weak signal, Intel 7260 adapter

I yesterday upgraded from Windows to Ubuntu 15.04 but I have problem with my wireless adapter Intel Corporation Wireless 7260 (rev 73). It randomly loses internet connection. Restarting adapter always helps. (same it did with Windows, except that sometimes restarting adapter didn't help).   Additionally, I have weaker connection then I had with Windows.  Thank you!


Booting a Windows 7 installation on different hardware

I'm in a situation where I could do with very quickly migrating a Windows 7 (RTM x64) installation from one machine to another.  What options are open to me in terms of getting W7 to boot after the drive is picked up and moved from one box to another? I thought it was supposed to be a little less sensitive to this kind of move than XP, but it doesn't work - it is stuck in a reboot loop and never reaches a GUI.  Tried a few things so far, none of which have worked:   Changed SATA mode in the BIOS of the target machine between ATA and AHCI run Windows 7 Startup Repair tried safe mode, no change   (I will keep this list up to date as suggestions come in)  UPDATE: I can confirm this reboot loop is due to STOP error 0x0000007B, and these codes follow:  0xFFFFF880009A98E8 0xFFFFFFFFC0000034 0x0000000000000000 0x0000000000000000    UPDATE: I didn't get anywhere on this and I ended up just rebuilding the machine. I think it should be theoretically possible, so I'm going to leave the question open in case someone comes along in future with an answer.


Is it necessary to rinse Chinese or other tea before first brew / steep / infusion?

I've been told that I should be rinsing Chinese tea with the boiled water before the first full infusion intended for drinking.  I make the occasional very-expensive tea from Taiwan and I feel it is a waste to throw away a first pot simply for "rinsing".  However, my mother-in-law insists it is correct to rinse the tea first :-)  Is this practice of rinsing always advisable, or are there specific cases or kinds of tea where rinsing is necessary? What are we trying to rinse away?  Is the practice only for Chinese tea, or for other kinds of tea as well?  Looking for some enlightenment from some tea experts.  Thank you!    Update:  Since I asked the question, my mother-in-law came across a newspaper article, in Chinese, describing pesticides found on some teas from China, and so it is advisable to rinse before consuming.  Here's a scan I made of the article:    Something in English...  Essentially, the article references a 2012 report by Greenpeace.  You can read a , and here's a link to the report itself: .  Press release summary:     A Greenpeace investigation has found pesticides banned for use on tea   in the products marketed by some of China's top tea companies. Some of   the firms, which include China Tea, Tenfu Tea and China Tea King,   export tea products to Japan, the US and Europe.   For that reason, I accepted the answer below which suggests rinsing for reduction of pesticides.  Of course, I don't think I'd want to drink a tea with 17 kinds of pesticides present, even if rinsed!  Caveat emptor ... I plan to ask more questions when I buy my tea.


Can you set a motion tracker as an empty?

I'm trying to make an object follow a path from a recording, and I'd like to do it with the motion tracker. I'm not trying to solve camera motion, just the object. I've got a tracker in the motion tracker, but I can't figure out how to make it an empty in the 3d space. (of course, it'll only move in two dimensions.)


Is it possible to have in the toc no word separation but have a word separation in the chaptername:  For example:   Contents  1. max Mustermann   Chapter  Max Muster- mann


Are there any converters that can take a Scientific Word code and make it pure LaTeX code?  Don't read what follows:  Below this line is some nonsense I had to write in order to be able to ask the question.


Broadcom Corp. BCM4313 Wirelss not detected in Ubuntu 12.10

I update my Toshiba PORTÉGÉ from Precise(12.04) to Quantal (12.10). After update to Precise wireless device works fine. But after update wireless device is not detect on network manager.  The lspci command says:  02:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN      Controller [14e4:4727] (rev 01)             Subsystem: Askey Computer Corp. Device [144f:7175]             Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-             Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-             Latency: 0, Cache Line Size: 64 bytes             Interrupt: pin A routed to IRQ 3             Region 0: Memory at d4500000 (64-bit, non-prefetchable) [size=16K]             Capabilities: <access denied>             Kernel modules: bcma   The ethernet connection works fine. I try to install firmware-b43-installer but it says:  $ sudo apt-get install firmware-b43-installer ... Unsuported device(s) found: PCI id 14e4:4727 Aborting   More info related gived by lshw:      root@caprica:~# sudo lshw -class network   *-network                       descripción: Ethernet interface        producto: 82577LC Gigabit Network Connection        fabricante: Intel Corporation        id físico: 19        información del bus: pci@0000:00:19.0        nombre lógico: eth0        versión: 06        serie: e8:9d:87:ed:f4:2a        tamaño: 1Gbit/s        capacidad: 1Gbit/s        anchura: 32 bits        reloj: 33MHz        capacidades: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation        configuración: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.0.0-k duplex=full firmware=0.12-6 ip=192.168.1.5 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s        recursos: irq:41 memoria:d4700000-d471ffff memoria:d472a000-d472afff ioport:3020(size=32)   *-network NO RECLAMADO        descripción: Network controller        producto: BCM4313 802.11b/g/n Wireless LAN Controller        fabricante: Broadcom Corporation        id físico: 0        información del bus: pci@0000:02:00.0        versión: 01        anchura: 64 bits        reloj: 33MHz        capacidades: pm msi pciexpress bus_master cap_list        configuración: latency=0        recursos: memoria:d4500000-d4503fff   I execute this too and this is the output:  root@caprica:~# rfkill list all 0: Toshiba Bluetooth: Bluetooth     Soft blocked: no     Hard blocked: no 1: hci0: Bluetooth     Soft blocked: no     Hard blocked: no   I have checking the model in :  BCM4313 - chipset uses unsupported LCN PHY, we work on it   I had configured privated drivers in the visual enviroment, Broadcom 802.11 Linux STA wireless driver source from bcmwl-kernel-source but don't work either.


Is there a nonempty perfect set in $R$ which contains no rational number? Its the excercise of Principles of Mathematical Analysis by Walter Rudin. I can't find the answer.I try to construct a set as cantor set but I can't prove it has no rational number or maybe it doesn't exist .Can anyone give me a hint ?I thought abt it for a whole day.


Saving multiple objects' location + rotation in RGBA

I recently asked a question in here, and wanted to ask a new one, as it was very convoluted, and I now know what I need to know. I need to save multiple objects' location in XYZ as RGBA data on an image. The colors should match that of blender in metric, so if I move the object up 0.719 meters in blender, the color should be 0.719. Just like shown here.  Furthermore I need to save their rotation in quaternions as RGBA as well, different image though. I've found this script, but it doesn't do exactly as I need, could it be rewritten, or how would I go about it? Since I also need the data from multiple objects, saved in a string of pixels.  For a visual reprensentation of what I need to do, I need to place these track elements (shown in green outline) in a shape to form the belt for a tracked mashine. Each pixel corresponds to one element and it's position/rotation. So the number of pixels should match the number of objects.  The rest will then be handled by the shader in the game. I've included an original file from the game, if it helps.  Thanks.


Is there a word for describing a person who experiences schadenfreude?

One word to denote a person who derives pleasure from another's misfortune?


What is the closed form for $ \sum_{n=1}^{\infty}n\theta^n, 0 \lt \theta \lt 1$?

I have the following series:  $$ \sum_{n=1}^{\infty}n\theta^n, 0 \lt \theta \lt 1$$  I've seen lots of resources saying this is convergent. And using convergence tests to prove that.   Question:     But is there any formula which gives the summation in closed form?


What argument to use for AOwner when constructing TComponent Descendents?

When I want to create a TComponent descendent using the Create method in delphi we must pass a parameter :  className.Create(AOwner)   where AOwner is of type TComponent  From what i know it accepts any one of three parameter(in default create cases)   Nil,Self, application    I did't quite understood when to use which.   Can someone please elaborate on same.


Should this "not an answer" flag have been disputed?

I recently flagged  as "not an answer".  It's a link-only answer without an actual link.  Full text:     For anyone still stuck, codeacademy.com has an excellent practical tutorial on prototypes in its js lessons called 'Introduction to Objects II' (sadly I can't provide a link as you have to register and login to see it, but it is easy to find).   And yet, I noticed that my flag was marked as "disputed" by a moderator.  Did the moderator make a mistake in this case, or is there a gray area here that I'm missing?


Does a legendary creature "die" when put into the graveyard due to the Legendary rule?

's text reads:      When The Scarab God dies, return it to its owner's hand at the beginning of the next end step.   If I have  in place and my opponent attempts to exile The Scarab God, can I in response, make Mirage Mirror a copy of it, then select the original Scarab God to be put into the graveyard, and finally return it at the beginning of the next end step?  The Legendary rule reads:     If a player controls two or more legendary permanents of the same name when state-based effects are checked, that player chooses one of those permanents and immediately put the others into their owners' graveyards, without any player having an opportunity to respond.   Is that "put the others into graveyard" considered "dying"?


Nilradical of a Noetherian Ring is intersection of finitely many primes

I am trying to prove that the nilradical of a Noetherian ring is the intersection of finitely many prime ideals but can not seem to do it.  I am trying to make a standard argument assuming, for contradiction, that the nilradical is not the intersection of finitely many prime ideals and deriving a contradiction but can't find one, any help is much appreciated.


Why we use "in" in: I worked in the mailroom.  While we use "at" and "in" in:   I worked in a place. I worked at a place.


Commandline shortcut for current directory similar to ~ for home directory?

When i use the cp or move command in a terminal window, i'm currently with bash in a certain folder like this.  NES@server:~/Desktop/dir1$   And now i wanna copy a file from here ~/anotherdir/dir2 into the current chosen folder in bash (dir1) i would use the command  cp ~/anotherdir/dir2/file ~/Desktop/dir1   does a shortcut string exist to refer to the current chosen directory? So that in this example i don't have to provide the full path to the target dir, but the command knows it should use the current chosen directory in bash? i.e. as ~ stands for the home directory?


Support for Wireless Network Interface PCI Cards as of now?

I am running Ubuntu 16.04 on my desktop.I use my smartphone as a wifi hotspot in case my Wired Broadband goes down or becomes unusable, So i thought of buying a usb wifi adapter and bought a TENDA TEW311MI Wireless N150 USB Adapter Nano from Amazon since it was the only one that said will support Linux OS and it did But after a few days it died,I have heard such instances with USB Adapter are a common thing,So i am thinking of getting a PCI Card for this,But i am not sure which of those supports Linux,So please guide me in this search with your knowledge and i prefer a card in the budget range. Thank you. Rahul


Prove that $\alpha$ is constant on the interval $[0,1]$.

Let $\alpha:[0,1]\to\mathbb{R}$ be a continuous function, and suppose that for any continuously differentiable "non-constant" function $\beta:[0,1]\to\mathbb{R}$ with $\beta(0)=\beta(1)=0$ satisfies the following integral equation:$$\int_{0}^{1}\alpha(x)\beta'(x)\,dx=0.$$ Prove that $\alpha$ is constant on $[0,1]$.   It looks very similar to a well-known problem(such as the above integrand of the form $\alpha(x)\beta(x)$, where $\beta(x)$ is any continuous function on $[0,1]$), but I don't know how to prove it.  I'd be grateful if someone could give me some advice. Thank you.


Perl's floor function is giving me unexpected results. floor(13320) = 13320, but floor(133.20 * 100) = 13319. I'd think both of those would get the same result. Why is this happening? use POSIX;  print floor(133.20);       # 133, as expected print floor(13320);        # 13320, as expected print floor(133.20 * 100); # 13319?


Why Landsat ETM+ panchromatic band' wavelength steps over visible range?

The Landsat ETM+ band-8 (Panchromatic) is identical to Landsat-8 OLI' Panchromatic band-8 in terms of spatial resolution i.e. 15 x 15m cell size. However, there is great difference in the wavelengths of both bands; ETM+ .52 - .90 and OLI 0.503 - 0.676 (micrometers).   See   Clearly, the wavelength placed for ETM+ steps over visible range. A visual comparison between both bands also indicates outcome of these differences.    Obviously, it is noticed that OLI' pan band is much handy in visual interpretation as well as suitable for pan-sharpening and image classification.  There might be some good aspects behind ETM+ panchromatic wavelength extending beyond visible range, I am interested to be enlightened about the same reason.


Can I stop 100% Width Text Boxes from extending beyond their containers?

Lets say I have a text box that I want to fill a whole line. I would give it a style like this:  input.wide {display:block; width: 100%}   This causes problems because the width is based on the content of the text box. Text boxes have margin, borders, & padding by default, which makes a 100% width text box larger than its container.  For example, here on the right:    Is there any way to make a text box fill the width of its container without expanding beyond it?  Here is some example HTML to show what I mean:  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">       <title>Untitled Page</title>

             <input type="text" class="wide" />             <input type="text" class="normal" />

     If this is run, you can see by looking at the "normal" text box that the "wide" text box is sticking out beyond the container. The "normal" text box floats to the actual edge of the container. I'm trying to make the "wide" text box fill its container, without expanding beyond edge like the "normal" text box is.


Seeking shapefiles of business locations

Does anyone know where to find shapefiles of businesses such as grocery stores or gas stations?


If $a$ and $b$ are positive real numbers such that $a+b=1$, then prove that $\big(a+\frac{1}{a}\big)^2 +\big(b+\frac{1}{b}\big)^2 \ge\frac{25}{2}$

If $a$ and $b$ are positive real numbers such that $a+b=1$, then prove that $$\bigg(a+ \dfrac {1}{a}\bigg)^2 +\bigg(b+ \dfrac {1}{b}\bigg)^2 \ge \dfrac {25}{2}$$   My tries: I am really unable to see through it. I have solved many inequality problems but somehow I am unable to solve this. I do not think my working will be of any help, so I am not typing those expressions.


In my preamble, you'll find:  \renewcommand{\baselinestretch}{1} \renewcommand{\familydefault}{\sfdefault} \usepackage[sfmath]{kpfonts} \usepackage[mathrmOrig]{sfmath} \usepackage{amsmath} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{animate} \usepackage{anysize} \usepackage{arcs} \usepackage{array} \usepackage[scale=0]{background} \usepackage{blindtext} \usepackage{calc} \usepackage{cancel} \usepackage{chngcntr} \usepackage{CJK} \usepackage{CJKspace} \usepackage{CJKpunct} \usepackage{colortbl} \usepackage{enumitem} \usepackage{epstopdf} \usepackage{etoolbox} \usepackage{fancybox} \usepackage{fancyhdr} \usepackage{float} \usepackage{framed} \usepackage{graphicx} \usepackage{hyphenat} \usepackage{ifthen} \usepackage{latexsym} \usepackage{lmodern} \usepackage{multicol} \usepackage{multirow} \usepackage{mwe} \usepackage{pgffor} \usepackage{rotating} \usepackage{tabularx} \usepackage{textcomp} \usepackage{tgheros,tgtermes,tgcursor} \usepackage{tikz} \usepackage{times} \usepackage{tipa} \usepackage{varwidth} \usepackage{wasysym} \usepackage{wboiboites} \usepackage[abs]{overpic} \usepackage[breaklinks,colorlinks=true,linkcolor=red,citecolor=red, urlcolor=blue]{hyperref} \usepackage[framemethod=TikZ]{mdframed} \usepackage[breakable, theorems, skins]{tcolorbox,empheq} \usepackage[default]{gillius} \usepackage[document]{ragged2e} \usepackage[latin1]{inputenc} \usepackage[spanish]{babel} \usepackage[T1]{fontenc} \usepackage[total={18.59cm,26.5cm},left=1.5cm,top=2.5cm]{geometry} \usetikzlibrary{matrix,arrows, positioning,shadows,shadings,backgrounds,calc, shapes, tikzmark} \usetikzlibrary{shadows.blur} \usetikzlibrary{shapes.symbols} \usetikzlibrary{patterns,fadings} \tcbuselibrary{skins,breakable,listings,theorems}    I'm trying to draw an arrow for X axis and Y axis.   \begin{tikzpicture} \draw[yellow!10, fill=blue!5](-1, -1) rectangle (7, 5); \draw[dotted] (-0.75,-0.75) grid (6.75,4.75); \node[below] at (-0.25,0){$O$}; \draw[->,black, thick] (-0.75,0)--(6.75,0); \end{tikzpicture}   But I get this error:    Additionally, if I remove -> from the options of \draw the tikz picture compiles normally.


Can a shell script running in a ssh continue to run if the SSH instance closes?

I'm trying to write a shell script that does a lengthy batch job on a remote server. I'll be running the script over SSH.   The thing is, I intend to start the script in the evening and collect the results the next morning; I'd prefer not to have my local computer have to run all night, as it's not needed as part of the batch process. As such, is there a way I can close the SSH connection and still have the shell script continue to run on the remote server?


How much beef brisket and how much pork butt  should I buy to feed 40 people. 95 % men. They will be making sandwiches and have slaw and dessert .Needed right away. Thanks..


Scala - Does pattern matching break the Open-Closed principle?

First of all, I know this question has been asked previously , but it wasn't clear for me.  Pattern matching is used to make a function react to different types of data. One would say that if my Pattern Matching case has 4 cases and one month later I need to add a 5th one, I'll be breaking the Open-Closed Principle. I agree to that.  In a worst case scenario: Let's suppose I'm using a closed library (I can't touch code inside it) and I need to extend its functionality. The functionality I want to extend is indeed a Pattern Matching function. What should I do?  I think pattern matching is OK if I'm totally sure my Object doesn't change very often and will never require to be extended by others.  What's your opinion about using this technique? This is more like a debate than a question.  Thanks,


Auto size image to page size in InDesign

I've got an InDesign document with 100 A4 pages.   I've got 100 assets (a mixture of .jpg and .pdf files) and I want to place 1 per page. If an image is not the proportion of the A4 page I would like to get it as big as it can be on the page before it hits into the margin. Ex. if it's a portrait image it should be as large as it can be before hits the top/bottom margin. If it's a landscape image it should be as large as it can be before hits the left/right margin.   At the moment I'm dragging each file across and resizing them manually. Is it possible just drop them on the page and get them auto resized ?


Tikz: Is it possible to change line style within same \draw command?

Is it possible to change the line style in a tikz figure in the same \draw command?  I am looking for something like:  \documentclass[tikz]{standalone} \begin{document}     \begin{tikzpicture}         \draw[style1] (0,0) -- ++(1,0)  **CHANGE STYLE** -- ++(1,0);     \end{tikzpicture} \end{document}   The main motivation is that I don't want to loose the relative coordinate as I go on with a long \draw command.


Ovelayed images show transparent in compositor

I am adding some overlay images in the compositor. But when I add the images it appears to be transparent.  Why is my image appearing like this?


Which queue for an unmarried EU/non-EU couple travelling through UK Immigration Control together?

I'll be arriving at Heathrow in June 2015 with my current girlfriend for a holiday in the UK. I've been trying to find out which immigration queue to join at Heathrow Passport Control without much luck. I have a British passport, my girlfriend has a non-EU passport.     Should I join the EU queue and she the non-EU queue or should we both queue together (and if so, which of the queues should we join)?


Why should I *not* use the KOMA-Script classes?

I've heard a lot of recommendations to use the KOMA-Script document classes in place of the base document classes. I appreciate that there is a lot of added functionality, and customisation is easier. But before I jump in, I would like to know of any potential problems with these classes.  In my particular case, I am writing a thesis - it's part of the way through, and I've been compiling using the base classes (report), and a bunch of packages. But in the interest of keeping the question broadly relevant, answers with problems that don't affect my use-case are more than welcome.


How do I exclude a set of files from a local git repository?

I have a remote repository with several sub-directories like so:  /Client1 /Client2 /Server   I would like to create a local repository that only pulls one of these sub-directories (Server), and only pushes back changes to this directory. How can I do this?  I know I could split these sub-directories into multiple git repositories, but I'm trying to find a way to avoid changing the structure of the remote repository.


Digitally selectable filter for the ST7580

For the , it uses PSK or FSK to send a signal over power lines. In the  the example is designed for an FSK or PSK signal to be transmitted at 80 kHz see page  for reference to the RX filter calculations below.     For my design I would like to send and receive signals across multiple bands. As this is industry related, I will have to stay away from CENELEC Band A. So I would like to make use of CENELEC Band B (102.5 kHz and 117.5 kHz), C (132.5 kHz), D and a part of the FCC Band (147.5 kHz); As the ST7580 can modulate up to 250 kHz but the RX filter need select these frequencies.   I would like to find out if the following sketch is a viable option:   This is just a crude drawing, the final design will only use one inductor and the capacitor will be selected with transistors rather than all the filter components.  The two main components of the filter is C3 and L2. I would like to know if I "take" GND away from the filter via a NPN transistor, will this lead to the effect that I am going for? (Which is to have four RX filters on the same board and simply flick between them with a few pins on my microchip). Only one transistor will be on at one time.  EDIT: To clarify I am just focusing on the , as shown in the figure below boxed in red, for now. This does not have the R5 resistor included, but it is a part of the circuit.     I eventually wish to make this a selectable BPF with a few transistors. Is this a valid method of performing this by changing L2 and C3?


What features in iOS 7 make a difference?

Share your experiences on exploring iOS 7 with us..  Whether you found hidden or little-known feature of iOS 7 or can explain how a big feature makes a difference, we're looking for objective reports of how the new OS affects your workflow.  Also provide details on how to achieve that feature, and if possible, include a relevant image too (hold Home and Lock for a screenshot on your iOS device).    Please post one tip per answer. Please also check to see if your answer has already been posted - duplicate answers will be deleted in favour of the original answer on any given topic. To search answers for this question use inquestion:101382 (or inquestion:this, directly from the question page) in addition to your search terms in the search box in the upper right hand corner of this page.


Suppose I want to sample from a continuous distribution $p(x)$. If I have an expression of $p$ in the form  $$p(x) = \sum_{i=1}^\infty a_i f_i(x)$$  where $a_i \geqslant 0, \sum_i a_i= 1$, and $f_i$ are distributions which can easily be sampled from, then I can easily generate samples from $p$ by:   Sampling a label $i$ with probability $a_i$ Sampling $X \sim f_i$   Is it possible to generalise this procedure if the $a_i$ are occasionally negative? I suspect I've seen this done somewhere - possibly in a book, possibly for the Kolmogorov distribution - so I'd be perfectly happy to accept a reference as an answer.  If a concrete toy example is helpful, let's say I'd like to sample from $$p(x,y) \propto \exp(-x-y-\alpha\sqrt{xy})\qquad x,y > 0$$ I'll then take $\alpha \in (0, 2)$ for technical reasons which should not matter too much, in the grand scheme of things.  In principle, I could then expand this as the following sum:  $$p(x,y) \propto \sum_{n=0}^\infty \frac{(-1)^n \alpha^n \left( \frac{n}{2} \right)! \left( \frac{n}{2} \right)!}{n!} \left( \frac{x^{n/2} e^{-x}}{\left( \frac{n}{2} \right)!}\right) \left( \frac{y^{n/2} e^{-y}}{\left( \frac{n}{2} \right)!}\right) .$$  The $(x,y)$-terms inside the sum can then be independently sampled from as Gamma random variates. My issue is evidently that the coefficients are "occasionally" negative.  Edit 1: I clarify that I am seeking to generate exact samples from $p$, rather than calculating expectations under $p$. For those interested, some procedures for doing so are alluded to in the comments.   Edit 2: I found the reference which includes a particular approach to this problem, in . The algorithm is from . The method is effectively to bound the density from above by the positive terms of the sum, and then use rejection sampling based on this envelope. This corresponds to the method described in @Xi'an's answer.


Will many tiny scratches on lens front element affect my photos?

I've bought a second hand Helios lens online (40 years old). At first sight everything looks fine no fungus haze no dust. Under 45 degree the front element in covered in very very thin scratches like it was cleaned with a T-shirt. I will test it next but I'm on film with no access to digital.  Will this affect the photos?


What are the mathematical problems in introducing Spin 3/2 fermions?

Can the physics complications of introducing spin 3/2 Rarita-Schwinger matter be put in geometric (or other) terms readily accessible to a mathematician?


How do you decline nouns borrowed from languages with several categories for declining nouns (or none at all)?

English has two grammatical categories of number.  One is the singular, and the other is the plural.  Many nouns in English have different singular and plural forms.  When nouns are borrowed from other languages into English, the plural form in the source language comes with it (at least sometimes).  However, not all languages have the same grammatical number categories that English has.  I think that some don't decline at all for number.  Some have more categories, like the dual and the trial[1].  If you import a noun from a language with more categories, do you use any different dual, trial, etc. forms that the noun has in the source language?  What about if you import a noun from a language that doesn't have grammatical number?  Do you decline it for number using English's "default" -s/-es scheme?  This is mostly or entirely contrived (currently, anyway).   See


Search whole database instead of single table

I want to find a number or string in a very large database. Is there any way to make an SQL Query that searches the entire database, and not just a single table?  I'm looking for something like:  select * from *;


I know that symmetric matrices can be positive or negative definite. But are only symmetric matrices definite?


Upvote not appearing in top bar, possibly linked to Necromancer badge

Today, I received a fifth upvote on one of my answers . As this was the fifth upvote on a new answer to an old question, it also earned me a .  The upvote and its +10 rep are displayed both on  as well as on the  (moderator version of timeline shown below):      However, it's not appearing in the top bar (which reflects a badge earned with an upvote):    I assumed this wasn't intended behaviour, so here's my  report.


C++ associative array with arbitrary types for values

What is the best way to have an associative array with arbitrary value types for each key in C++?  Currently my plan is to create a "value" class with member variables of the types I will be expecting. For example:  class Value {      int iValue;     Value(int v) { iValue = v; }      std::string sValue;     Value(std::string v) { sValue = v; }      SomeClass *cValue;     Value(SomeClass *v) { cValue = c; }  };  std::map<std::string, Value> table;   A downside with this is you have to know the type when accessing the "Value". i.e.:  table["something"] = Value(5); SomeClass *s = table["something"].cValue;  // broken pointer   Also the more types that are put in Value, the more bloated the array will be.  Any better suggestions?


How does Geordi read and work with numbers?

Geordi's VISOR images, as seen in "The Mind's Eye" and a couple other episodes, are not the clearest pictures in the world. Individuals are fuzzy, for example, which leads me to ask: How does Geordi read? While working at his Engineering station, how does he see and deal with small numbers and figures on the console? Wouldn't the words and numbers be illegible?


I connected a 1.3" SH1106 Oled via the I2C pins to a i2c-to-usb adapter (UMFT201XB from FTDI) and on my Linux Box (Z83 mini pc with Ubuntu 18.04) I can see the device under /dev/ttyUSB0.  This is the dmesg output:  [16123.056915] usb 1-2: new full-speed USB device number 15 using xhci_hcd [16123.212789] usb 1-2: New USB device found, idVendor=0403, idProduct=6015 [16123.212806] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [16123.212816] usb 1-2: Product: UMFT201XB [16123.212825] usb 1-2: Manufacturer: FTDI [16123.212834] usb 1-2: SerialNumber: FTWCN8T5 [16123.216185] ftdi_sio 1-2:1.0: FTDI USB Serial Device converter detected [16123.216361] usb 1-2: Detected FT-X [16123.216947] usb 1-2: FTDI USB Serial Device converter now attached to ttyUSB0   Now I want to write text/graphics to the OLED screen but I cannot find the i2c device with i2cdetect -l. After plugging in the USB, I don't see a extra device there (maybe there should not even be one?).  I use the luma.oled library on the Linux Box, but for the initialization, I need the i2c port and i2c address (somewhere in the docs they mention 0x22, but what port?).  How can I find the port for the USB adapter, if there is even one. I am a complete noob with i2c and virtual serial ports, so maybe my approach is completely wrong.


How is $\mathrm dU=C_V\,\mathrm dT$ always true?

For ideal gases, in case of an isochoric process it is pretty straight forward:  $\mathrm dU=Q+W$  $\Rightarrow\mathrm dU=C_V\,\mathrm dT+p\,\mathrm dV$  $\Rightarrow\mathrm dU=C_V\,\mathrm dT$  But in case  of an isobaric process,  $\mathrm dU=Q+W$   $\Rightarrow\mathrm dU=C_p\,\mathrm dT-p\,\mathrm dV$   I tried deriving it this way but I'm stuck. How do I get $\mathrm dU=C_V\,\mathrm dT$ for an isobaric process?  And I have no clue how to derive it for an adiabatic process either, so how do you get the expression for $\mathrm dU$ for an adiabatic process?  Edit: I have thought of substituting $pdV = RdT$ then plugging in $R=C_p-C_v%$. But I was hesitant. Is $du=C_vdT$ because $R=C_p-C_v$ or the other way around?


I'm using the  to place a dollar sign and a decimal into a a couple of text fields. Now I want to add these two values, but I'm getting the NAN error because of the dollar sign that is placed in front of the number.  How do I remove the dollar sign (first character), add the values and place the total value into another field?  Sample HTML  <input type="text" id="value_one" />
 <input type="text" id="value_two" />
 <input type="text" id="total_value" />
   Sample jQuery  $("body").hover(function() {     var a = +$('#value_one').val();     var b = +$('#value_two').val();     var total = a+b;     $('#total_value').val(total); });


How can I delete a file named "--append"?

By mistake I have created a file named : --append.  How do I delete it?  Simply entering the usual command, rm -f --append, doesn't work.


monkey-patching python an instance method

I'm trying to monkey-patch a class instance, but don't quite see how I can patch a class method no problem.  >>> class Simple(object):  ...     def make(self, arg): ...         return arg * 2 ...  >>> s = Simple() >>> def times_four(self, arg): ...   return arg * 4 ...  >>> Simple.make = times_four >>> s.make(10) 40   But say I only wanted to replace make in the instance, what's the easiest way to do that?  >>> def times_eight(self, arg): ...   return arg * 8 >>> s.make = ???


What is the rule and meaning of does in the following sentence (I think the appear omitted by it but if I am wrong please correct the title and tag):     The Moon illusion is an optical illusion which causes the Moon to appear larger near the    horizon than it does higher up in the sky. ()   MORE EXAMPLES   Sound travels faster in liquids and non-porous solids than it does in air (). This makes it possible for the Sun to rotate faster at its equator (about 25 days) than it does at more extreme latitudes (about 35 days near its poles) (). The Sun appears larger at sunrise than it does while higher in the sky, in a manner similar to the moon illusion ().


In chemistry, I studied the decomposition of water as being $2H_2O_{(l)} \rightarrow 2H_{2(g)} + O_{2(g)}$. However, when water is split, the equation is $2H_2O_{(l)} \rightarrow 4H^+ + 4e^- +O_{2(g)}$. Why is that? How does $H_2$ just ionize?  Moreover, what is the mechanism for photolysis? I would have thought that splitting water molecules requires a ton of energy; yet it can be accomplished simply with light energy during photosynthesis?


Create foreign key on foreign table in postgresql

I need to link my table with another one which is in different database(say table logs in device db and table accounts in user db, both on same server). So using  I create a foreign table(I check it with running select * from accounts; in device db which works successfully).  But I could not create a foreign key to foreign table from device db still  CREATE TABLE public.logs (   id bigint NOT NULL DEFAULT nextval('logs'::regclass),   ...   account_id bigint,   ...    CONSTRAINT logs_account_id_fkey FOREIGN KEY (account_id)       REFERENCES public.accounts (id) MATCH SIMPLE       ON UPDATE NO ACTION ON DELETE NO ACTION  )   The error message is  ERROR:  referenced relation "accounts" is not a table ********** Error **********  ERROR: referenced relation "accounts" is not a table SQL state: 42809


I'm using QGIS 2.6 and regularly update a shapefile layer to indicate felling progress. However, if I edit the nodes of a polygon, save the layer out then look at the Attributes table the area shown doesn't change.


Can a large file be hashed down to 32 bytes, and then reconstructed from the hash?

We can hash a file or data using multihash or SHA-256, but can we retrieve the original data or file from the hash?  Are there any methods to retrieve the original file or data from a hash of it without using IPFS?  Or is there any encryption method which encrypts a 5 MB file and outputs a hash-like content of 32 bytes so that we can retrieve the original file from that 32 byte content?


When I have Excel running and I double click an Excel file in Windows explorer, I'd like it to launch in a new window by default so that I can move documents to separate monitors. Is there any way to get this behavior?


What are jQuery's Backwards Compatibility Guarantees

Does jQuery make any version-to-version compatibility guarantees?  For example following  or do you just have to read the release notes every time?  Note: I have seen  that ask how good compatibility has actually been.  This question is strictly about the promises made by the project.


Is there a good automatic time tracking tool for Mac OS X

I'm searching for an automatic time tracking tool for Mac OS X. I regularly mess up manual time tracking with timers etc., so I want something more automatic:  The application should run in background and track more or less everything I do - which applications are active, which sites I browse, how long I'm idle etc.  It would then list all the things I do in a timeline and let me specify filters like "Xcode in foreground", "browsing developer.apple.com", etc. Using these filters, I could check how long I worked on what after I left work.  Is there an application which does this? I'm aware of a website and a client for it, but I'm absolutely NOT comfortable with putting all the things I do on some random website.


I want to understand the concept of open-drain ports like port P0 of the 8051 microcontroller. Why do we need to connect pull up resistors to the port P0?   I have basic knowledge of MOSFETs and other electronic devices.


With what probability does nuclear fusion occur at energies far below the Coulomb barrier?

Even at the core of the sun, the temperature of $\sim 10^7$ K only results in $kT\sim1$ keV, which is about a thousand times less than the electrical potential energy of $\sim1$ MeV needed in order to bring two hydrogen nuclei to within the ~1 fm range of the strong nuclear force. Therefore nuclear fusion reactions can only occur inside the sun, or in any other normal star, through the process of quantum-mechanical tunneling. The low probability of this tunneling, along with the need for a weak interaction in order to fuse two protons into a deuterium nucleus, are the two factors that make stars have lifetimes billions of years long.  How is the tunneling probability calculated?


How to convert a number to words in MS Excel Android app?

Excel Macros are unsupported in Android and there is also no SpellNum Function in Android . I want a function which can convert a number to words. Is there any way we can achieve this ? eg -  40004  , should be converted to Forty Thousand Four


How do I prompt for Yes/No/Cancel input in a Linux shell script?

I want to pause input in a shell script, and prompt the user for choices. The standard Yes, No, or Cancel type question. How do I accomplish this in a typical bash prompt?


How can I make my browser lie about my operating system?

I'm using Chromium (Version 30.0.1599.114 Ubuntu 12.10) under Linux. I'm trying to access  that claims that it doesn't work under Linux. Of course, this is most likely crazy since the web is platform-independent (unless they're using some kind of evil plug-in).  I've used a user agent switcher to supply a Windows user agent, but to no avail. Upon viewing the source, it appears that the site is using Javascript to determine the operating system. I'm looking for a way to get my browser to report in Javascript that it is Windows or MacOS.  Do you know how to do it?


Where can I see a list of all my questions on Stack Exchange?

I want to be able to see a list of all the questions I have ever asked on the whole of the platform.  This is because there is useful material and references in the answers and comment posts.  I really need a list of my questions in one place!


Evaluating a sum involving binomial coefficient in denominator

I came across the following sum: $$\sum_{k=0}^{\infty} \frac{(-1)^k}{(2k+1)^2}\frac{4^k}{{2k \choose k}}$$    I thought that this can be evaluated using the expansion of $\dfrac{\sin^{-1}x}{\sqrt{1-x^2}}$ but I couldn't make any use of it. Then I tried to use the following: $$\frac{1}{(2k+1)}\frac{1}{{2k \choose k}}=\frac{\Gamma(k+1)\Gamma(k+1)}{\Gamma(2k+2)}=\int_0^1 x^k(1-x)^k\,dx$$ but this didn't help either and now I am stuck.   Any help is greatly appreciated. Thanks!    EDIT:  The sum originated from the following definite integral:  $$\int_0^{\pi/2}\tan^{-1}(\sin x)\,dx$$


I recently went to the US and was a little bit confused about the tipping procedure sometimes. I found many resources on how much to tip, but now how exactly it goes down. To my understanding, tipping in cash is preferred in most places, so that is what I tried to do. The problem is, that I used the credit card more often than cash, so I did not have enough change/small bills to pay an adequate tip. Let's see how I usually payed:   Receive check Give credit card Receive receipt Leave tip in cash Leave restaurant   What do I do if I do not have the right amount of cash to tip at step 4? Assuming I want to tip $10, is it okay to give a $20 and ask for $10 back? If I have no cash left, when do I say how much I want to tip? Is it acceptable to leave the tip at the table and leave?


There are $50$ persons in a row of locked cells. With return of the king from the Crusade, a partial amnesty is declared and it work like this.  When the prisoners are stills asleep, the jailer walk past the cells $50$ times, each time walking from left to right. On the first past, the turns the lock in every cell (so that every cell is open ). On the second pass he turns the lock on every second cell (meaning that these cells are now locked again ) . on the third pass, he turns the lock on every third cell , and so on . In general, on the $k th$ pass, he turns the lock on every $k th$ cell. The question is : which cells are unlocked at the end of the process so that the prisoner is free to go?


How do I split a multi-line string into multiple lines?

I have a multi-line string literal that I want to do an operation on each line, like so:  inputString = """Line 1 Line 2 Line 3"""   I want to do something like the following:  for line in inputString:     doStuff()


I am working on a requirement wherein string(as a combination of boolean values) is to be evaluated. eg: '(TRUE && TRUE)'. Boolean.valueof() seems to work only with single stringified boolean eg : boolean.valueof('TRUE'). I was wondering if there is an OOTB way to convert the string to object form and then convert object to boolean. Something like:   String str = '(TRUE && TRUE)'; Object obj = str; Boolean bool = (Boolean)obj;


Hopefully my title makes sense I am not very good with character encoding. Anyway I have an application and I sometimes get input that looks like this ❤❤❤❤❤❤❤❤ and then it's saved to my db which is utf-8 encoded and it looks like this â¤ï¸â¤ï¸â¤ï¸â¤ï¸â¤ï¸â¤. When the user then requests the information again it looks like the latter. How can I save this data to my database and return it to the user looking the same as it was sent to me? I have looked around for some libraries that would do this but wasn't able to find any.


I have a switch that controls the top and bottom of an outlet.  I would like to make the outlet hot all the time.  Additionally I would like to install a light fixture, convert the existing single switch to a 3 way and install a new 3 way switch on a different wall.  @tester101 explained to me how to do something similar yesterday, but without the 3 way switches.  What is the best/easiest way to accomplish this? EDIT  Switch  Back of the switch  Outlet Back of outlet


PreExistingConfigException: Configuration objects provided by progweb_migration already exist in active

I'm playing with migrations from D7 to D8 and I've found that, when you register a module with a migration, if you disable it, next time you enable the module gets stuck on this:  [vagrant@devbox] /[...]/default $ drush en progweb_migration -y PHP Warning:  Module 'imagick' already loaded in Unknown on line 0 PHP Warning:  Module 'imagick' already loaded in Unknown on line 0 The following extensions will be enabled: progweb_migration Do you really want to continue? (y/n): y exception 'Drupal\Core\Config\PreExistingConfigException' with message 'Configuration objects[error] (migrate.migration.custom_user) provided by progweb_migration already exist in active configuration' in /www/drupal8/core/lib/Drupal/Core/Config/PreExistingConfigException.php:70 Stack trace: #0 /www/drupal8/core/lib/Drupal/Core/Extension/ModuleInstaller.php(162): Drupal\Core\Config\PreExistingConfigException::create('progweb_migrati...', Array) #1 /opt/drush7/vendor/drush/drush/commands/core/drupal/environment.inc(129): Drupal\Core\Extension\ModuleInstaller->install(Array, true) #2 /opt/drush7/vendor/drush/drush/commands/core/drupal/environment.inc(196): drush_module_install(Array) #3 /opt/drush7/vendor/drush/drush/commands/pm/pm.drush.inc(1120): drush_module_enable(Array) #4 [internal function]: drush_pm_enable('progweb_migrati...') #5 /opt/drush7/vendor/drush/drush/includes/command.inc(359): call_user_func_array('drush_pm_enable', Array) #6 /opt/drush7/vendor/drush/drush/includes/command.inc(210): _drush_invoke_hooks(Array, Array) #7 [internal function]: drush_command('progweb_migrati...') #8 /opt/drush7/vendor/drush/drush/includes/command.inc(178): call_user_func_array('drush_command', Array) #9 /opt/drush7/vendor/drush/drush/lib/Drush/Boot/DrupalBoot.php(46): drush_dispatch(Array) #10 /opt/drush7/vendor/drush/drush/drush.php(76): Drush\Boot\DrupalBoot->bootstrap_and_dispatch() #11 /opt/drush7/vendor/drush/drush/drush.php(16): drush_main() #12 {main}   It's like the migration is being registered but not de-registered. In D7 there is a method for that, but no luck so far trying in D8:  function progweb_migration_enable() {   Migration::registerMigration('custom_user');   Migration::registerMigration('custom_blog');    Migration::registerMigration('ProgwebBlog');   Migration::registerMigration('ProgwebUser'); }  function progweb_migration_disable() {   Migration::deregisterMigration('custom_user');   Migration::registerMigration('custom_blog');    Migration::deregisterMigration('ProgwebBlog');   Migration::registerMigration('ProgwebUser');  }   Any ideas?


I was playing around with aliases today and I noticed that aliases don't seem to be available whilst using sudo:  danny@kaon:~$ alias alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --color=auto' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto'  danny@kaon:~$ ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 //  danny@kaon:~$ sudo -i root@kaon:~# ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 // root@kaon:~# exit logout  danny@kaon:~$ sudo ll -d / sudo: ll: command not found   Is there any reason why you cannot use aliases whilst using sudo?


I made the mistake of getting a windows phone because the price was enticing. I want to run android O.S. if at all possible, being a working full time school full time person I'm looking to save money. Really I need the applications so I can interact with the rest of the world.


Recently I came across this summation: $$\sum_{k=0}^n\cos\Bigl(k\frac{2\pi}{n}\Bigr)$$ when I was trying to evaluate the following summation $$\sum_{k=0}^{n} z^k+z^{-k}$$ where $z \in \mathbb{C}, z=\operatorname{cis}(\frac{2\pi}{n})$ But I got stuck... Could anyone give me a tip ? Thanks in advance!


When I get the hour of a time, it prints it in the 24 hour clock like this;  time1 = datetime.datetime.strptime("08/Jan/2012:08:00:00", "%d/%b/%Y:%H:%M:%S") print 'hour is ', time1.hour  > time is  8   I'm trying to get it to show 08, instead of 8. For hours that are double digits its fine, but as soon as it gets to a single digit I'm trying to get that 0 in front of it.  I could potentially do 'time1.time' and then convert to string and then split it, and then convert the hour back into a datetime object, but this is pretty long winded and was wondering if there's a simpler solution?


Is there an intuitive explanation for the Southward force caused by the Coriolis Effect on rotating spheres?

From the  article on Wikipedia, the following with regard to the Coriolis Effect on a rotating sphere:     By setting vn = 0, it can be seen immediately that (for positive φ and ω) a movement due east results in an acceleration due south. Similarly, setting ve = 0, it is seen that a movement due north results in an acceleration due east. In general, observed horizontally, looking along the direction of the movement causing the acceleration, the acceleration always is turned 90° to the right and of the same size regardless of the horizontal orientation.   My intuitive (but possibly incorrect) understanding is that if there are two points, Point A and Point B, at different latitudes in the Northern hemisphere, the Eastward velocities of these points are different because they are at different distances from the Earth's axis of rotation, and this causes the Coriolis effect for a rotating sphere.  If a projectile is fired due North from Point A near the Equator towards Point B near the North Pole, the projectile will start off with the higher Eastward velocity of Point A, and will land to the East of Point B, which is moving East at a slower velocity than the projectile.  Firstly, is that correct?  If that IS correct, that brings me to the quote off Wikipedia. The quote implies that, if a projectile is fired due East, it will experience a Coriolis force to the South. My intuitive explanation based on differences in velocities between origin and destination does not account for a Southwards movement at all, since the Point A and Point B velocities are identical if the points are on the same latitude.  What am I missing? Would a projectile fired due East or due West experience any North or South drift caused by the Coriolis effect (or anything else for that matter)?  Why?


div's width is 100% so there's lot of extra space left at right. I want div to wrap the text inside it i.e. no extra space should be left in the block. How to achieve it? <div style="border: 1px solid black;">   Hello there! </div>


How to find the files have been removed in Shell?

If I deleted a file, how am I able to display that file just removed? For example: I deleted a file named A, if I run my shell, that will display file A have been removed.


Empty drives show 2 GB used, Explorer shows nothing

I have 4 drives in Windows: C:, D:, E: and F:. Except C:, all of them are empty.    Suddenly it shows up to 2 GB space used – even when there are no files.     [  When I format the drives, it's fine for a while until it shows used space again.  I use Windows 8.1 Pro 64 Bit.


How to convert a HEIF/HEIC image to JPEG in El Capitan?

So, here’s the thing. I have a new iPhone and an old Mac. iOS 11 (still in beta as of today) and El Capitan (no more updates for this Mac). I use iCloud photo library in both devices. When I take a photo in the new format with my iPhone 7, is there any way to use it right away in my mac, without having to convert it in my iPhone first? I mean, can I get those photos synced through iCloud and converted locally on my Mac?  I have tried to find a third party software that could do that kind of conversion, but was not able to find any that would work on El Capitan. Any idea?


I've recently searched how I could get the application's directory in Java. I've finally found the answer but I've needed surprisingly long because searching for such a generic term isn't easy. I think it would be a good idea to compile a list of how to achieve this in multiple languages.  Feel free to up/downvote if you (don't) like the idea and please contribute if you like it.  Clarification:  There's a fine distinction between the directory that contains the executable file and the current working directory (given by pwd under Unix). I was originally interested in the former but feel free to post methods for determining the latter as well (clarifying which one you mean).


Find all solutions to $$a^b = b^a$$ where $a, b$ are natural numbers with $a<b$.  So far I've been able to conclude that this is equivalent to $$\frac{log(a)}{a} = \frac{log(b)}{b}$$ but I'm not sure how to proceed. Can someone please give me a hint?


I found a Mass Effect 2 game in one of the stores in the Philippines, but they said that my Xbox must be a US Version, and that it won't work as my Xbox is a Japanese Version. I later found out on the internet that Mass Effect 2 is region free. Is it true?


Andrew Stacey  that the Rosetta Code entry  doesn't have a TikZ entry yet.  Is there a way to draw a "properly" shaded sphere using TikZ? The ball shading would seem an obvious choice, but it uses a circular highlight, which is not what it would look like in reality. So: is there a way to make a sphere that would resemble a white, matte (i.e. non-shiny) ball that is illuminated by a single white light source?  This would mainly require getting a non-circular, correctly oriented highlight, I believe. Both Yori's and Altermundus' answer already do a great job at using a "softer" highlight, which looks more believable, but Altermundus' highlight is still circular, and while Yoris' is elliptic, it's not oriented correctly, I think.  Compare a circle with the ball shading to the :    \documentclass{article}  \usepackage{tikz}  \begin{document}  \begin{minipage}{2.5cm}\centering \scriptsize That's not a sphere.  \tikz{     \fill [black] (-1,-1) rectangle (1,1);     \shade [ball color=white] (0,0) circle [radius=1cm]; } \end{minipage}% % \begin{minipage}{2.5cm}\centering \scriptsize \emph{That's} a sphere.  \includegraphics[width=2cm]{Sphere-perl6.png} \end{minipage} \end{document}


On my Windows 7 PC, the free disk space has gone down by 1GB even though I haven't downloaded or installed any new files and I haven't downloaded any updates or other things? What could have made the disk space go down for apparently no reason? Is this the result of some sort of a spy program that is undetectable?


I have just burned an .iso onto a usb drive, and i suspect something has gone wrong as it won't boot, so i want to wipe it and try again, but it won't let me remove files. When I use fdisk -l I get:  Disk /dev/sda: 119.2 GiB, 128035676160 bytes, 250069680 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xd9dca955  Device     Boot     Start       End   Sectors   Size Id Type /dev/sda1  *         2048 233469951 233467904 111.3G 83 Linux /dev/sda2       233471998 250068991  16596994   7.9G  5 Extended /dev/sda5       233472000 250068991  16596992   7.9G 82 Linux swap / Solaris   Disk /dev/sdb: 14.3 GiB, 15376000000 bytes, 30031250 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes   But under /dev/sdb there used to be a devices section like with /dev/sda, I'm assuming its to do with that. How do I get that back?


What is the interpretation of the whitespace in this command foo= bar ?   Why are foo=bar and foo= bar interpreted differently  Example (Ubuntu bash)  developer@1604:~$ foo=bar developer@1604:~$ foo= bar The program 'bar' is currently not installed. You can install it by typing: sudo apt install bar


Why would the Force become so mysterious and unrecognized after only 20 years?

I always wondered why Admiral Motti and Governor Tarkin in the movie  insinuate that the Force is an old, dead religion?  :     The Jedi are extinct, their fire has gone out of the universe. You, my friend, are all that's left of their religion.   :     Don't try to frighten us with your sorcerous ways, Lord Vader. Your sad devotion to that ancient religion has not helped you conjure up the stolen data tapes, or given you clairvoyance enough to find the rebels' hidden fortress...   Tarkin, as human, must be around age 50, so, if in Episode IV Luke is about 20, when he was just born at the end of Episode III, Tarkin must have been around 30, so a perfect young man in a Galaxy that used to know Jedis, Jedi Council, Force etc..  Why, 20 years later, he just looks like someone who never saw a Jedi/Sith? Also, besides from Force sensitives (Obi-Wan, Yoda, Vader, the Emperor), nobody else looks like they ever heard of the Force ... that's really weird, isn't it?


How to retrieve the wireless password from a DIR-651 without resetting it?

I need to grab the wireless password from my DIR-651 router and put in my phone.  I set the router up several months ago and haven't used wireless since.  I have access to the DIR-651 admin page via wired connection, but I am not finding where the wireless passwords are located.  I've looked all over the Manual Wireless setup page.  There is a "pre shared" key at the bottom, but even that is obscured (dots).


I am not sure about this but these are my current thoughts. X.org is an implementation of the X11 protocol and X11 is just a protocol and not a piece of software. My question is that is Wayland a completely new protocol that aims to completely replace X11 or is it supposed to replace X.org and implement X11? I am relatively new to display managers and WMs so I may need to clear some misconceptions!


I find myself adding more comments than answers in an attempt to help the OP's improve their questions.  One would get notifications of responses only if the commenter (either the OP or other user) would @ping the username.   Often times, new users in particular, do not know they need to @ping commenters back and requires me to track back questions to monitor for a eventual response.   This is clearly unpractical and consumes time that could be better.  My feature wish is to have some form of "smart subscribe" to a question that would notify me of comments that could be potential responses to my intervention. Ideally it would pop in the inbox, but maybe be labeled different to indicate that it's a suggestion rather than an explicit.  Or it could be as simple as a "subscribe" button (but not RSS. Who uses that these days?)


Why do backgrounded processes sometimes stop spontaneously?

Sometimes, some time after I've backgrounded a process with bg in bash, when I press Enter in the same shell to redisplay the prompt (just to check that I'm still in bash when some output from the background process has been displayed), the background process seems to stop spontaneously.  If I do bg again the same problem recurs.  The only way to fix it seems to be fg.  Why does this happen?


Command to display first few and last few lines of a file

I have a file with many rows, and each row has a timestamp at the starting, like  [Thread-3] (21/09/12 06:17:38:672) logged message from code.....   So, I frequently check 2 things from this log file.   First few rows, that has the global conditions and start time is also given. Last few rows, that has the exit status with some other info.   Is there any quick handy single command that could let me display just the first and last few lines of a file?


Let $p$ a prime number, then prove that : $\sum \limits_{k=0}^{p} \binom {p}{k} \binom{p+k}{k} \equiv 2^p +1 \pmod{p^2}$

First we know the fact that $p$ divides $\binom {p}{k}$ for $k\in \{1,\ldots,p-1\}$.  Second we have : $\binom {p+k}{k}= \frac{(p+k)\cdots(p+1)}{k!}$ which means : $k!\binom {p+k}{k}=(p+k)\cdots(p+1)$.  Notice that every term of the product is divided by $p$ except the last product $k(k-1)\cdots1=k!$  So $p$ divides $k!(\binom {p+k}{k} - 1)$. By Gauss lemma for $k\in \{1,\ldots,p-1\}$, $p$ divides $(\binom {p+k}{k} - 1)$.  Then $p^2$ divides $\binom{p}{k}(\binom {p+k}{k} - 1)$. We obtain : $\binom{p}{k}(\binom {p+k}{k} \equiv \binom{p}{k} \pmod{p^2}$.  So : $\sum \limits_{k=0}^{p} \binom {p}{k} \binom{p+k}{k}\equiv 1 +\binom{2p}{p} + \sum \limits_{k=1}^{p-1} \binom{p}{k} \equiv 1 +\binom{2p}{p} +2^{p}-2 \pmod{p^2}$  Then I'm stuck...  Maybe it is possible to prove that $\binom{2p}{p} \equiv 2\pmod{p^2}$..  Thanks in advance !


I've looked everywhere but can't seem to find a way to edit my profile from the iOS app - is this even possible?


Notation for repeated composition of functions

I have a repeated composition of functions ${T_n}(z) = {\tau _0} \circ {\tau _1} \circ {\tau _2} \circ  \cdots  \circ {\tau _n}(z)$  By analogy with $\sum\limits_{i = 1}^n {} ,\prod\limits_{i = 1}^n {} ,\bigcup\limits_{i = 1}^n {} ,\bigcap\limits_{i = 1}^n {} ,$ I want to write ${T_n}(z) = \left( {\mathop  \circ \limits_{i = 0}^n {\tau _i}} \right)(z)$ or even ${T_n}(z) = {\mathop  \circ \limits_{i = 0}^n {\tau _i}} (z)$. Can I do this?


Can't save batch file shortly after running it on Windows 7

I'm working on a batch file in Windows 7 Ultimate. I'm using notepad++ with the runme extension.  When I run the batch file and make some changes directly after that, I am not able to save the .bat file, because windows says it's been used by another process.  So I need to wait about 60 seconds until I'm able to re-save the file to test the changes.  Same goes when using the built-in Notepad.  Strangely I can delete the .bat file directly after running it, but saving doesn't work.  Some months ago, when I was working on another batch-file, everything was working ok.  Is there any way to stop this strange behaviour? Or is there at least any way to see which process is blocking the file?


How to delete old versions of same packages from a Local Repository?

In my local repository see below, I have many versions of same packages downloaded and stored in deb package directory. As Ubuntu always prefer to use the highest version, I don't need the earlier versions downloaded and used. (All are in a same folder).   How can I delete the earlier versions of packages from my local deb's folder ? It is not a feasible solution to delete them manually. (You can't examine the versions in thousands of files)   Any ideas?!!  Maybe a script that checks the version of each package keeping the newer version and deletind older ones can solve this issue.  I am seeking for such script or if some software is founded would be great  I have made my local repository following .  *** A local repository is an offline storage of packages already downloaded, so that you don't need to download it again)   Note: I'm not referring to clearing the cache of downloaded packages, which can be done with apt-get clean command.


How do I change the properties of my subsubsection headers (ie. make them bold)?

I want to be able to put my subsubsections in bold - currently they are displayed in italics by default.  What I have:  1. Section  1.1 Subsection  1.1.1 Subsubsection  What I want:  1. Section  1.1 Subsection  1.1.1 Subsubsection  The top of my Latex document currently looks like:  \documentclass[12pt, onecolumn]{revtex4}     \usepackage{times}                               \usepackage[a4paper, left=2.5cm, right=2.5cm,  top=2.5cm, bottom=2.5cm]{geometry}     \renewcommand{\baselinestretch}{1.15} \usepackage[font=small,labelfont=bf]{caption}                        \usepackage{graphics,graphicx,epsfig,ulem}   \usepackage{amsmath}                             \usepackage{etoolbox}                       \makeatletter \patchcmd{\frontmatter@RRAP@format}{(}{}{}{} \patchcmd{\frontmatter@RRAP@format}{)}{}{}{} \renewcommand\Dated@name{} \makeatother  \usepackage{fancyhdr} \usepackage{siunitx} \usepackage{hyperref} \usepackage{footmisc} \usepackage{float}  \pagestyle{fancy}                            \renewcommand{\headrulewidth}{0pt} \rhead{Insert Title Here}  \def\thetable{\arabic{table}} \def\thesection{\arabic{section}} \def\thesubsection{\arabic{section}.\arabic{subsection}} \def\thesubsubsection{\arabic{section}.\arabic{subsection}.\arabic{subsubsection}}    \def\bibsection{\section*{References}}  \begin{document}                     \end{documnet}


I've recently started observing that the highlighting of questions in a site's overview page has stopped working. I've observed this on:    sql_server tagged question  not highlighted    sql-server tagged question not highlighted    windows-10 tagged question not highlighted   ...and possibly others affected.


I got Apache working on localhost ("it works!"), but now how do I get it to work on the internet?

I can see my "website" locally but how do I get it to show up online? Does it need a domain name per se or can't I just get DNS somehow to pick up my IP address and put it online or something, I don't know. I've got a domain name registered, if that helps.


FIrefox - Why does ALT+A select all text and not CTRL+A?

Since I am so used to using the standard Ctrl+-a to select all, I am wondering why in Firefox I have to use Alt-a?   I just downloaded this  -- in the hope of solving this issue, but on opening the preferences for this add-on I see that the keyboard command is already set-up as Ctrl-a. However that is not the case in reality.  Is this something deeper in Ubuntu that needs changing? I think there are some other programs, although I cant think of them of the top of my head that also use the Alt-a to select all, although there are some that don't. Leaf Pad for example uses the standard Ctrl-a.  I just upgraded to 14.04, and was using 13.10 before that, in either case the problem is the exactly the same.


Every subgroup $H$ of $G$ with $H\ne G$ is cyclic. Is $G$ cyclic?

Let $(G,*)$ be a group. Suppose that every subgroup $H$ of $G$ with $H\ne  G$ is cyclic. Is $G$ cyclic? Justify your answer.  What i tried  I mentioned that $G$ is not necessarily cyclic. Using Lagrange theorem every subgroup of $G$ has an order which is the  divisor of the order of $G$. Say if the order of $G$ is $6$ then every subgroup must have an order of $1$, $2$, or $3$ for this case. And since all the subgroup are cyclic, then this implies that $G$ must have elements of order of $1$ , $2$ and $3$ but $G$ does not necessarily need to have an element of order $6$ which is the necessary condition for $G$ to be cyclic, since for $G$ to be cyclic the order of an element in $G$ need to be equal to the order of the group and this provide a counterexample. However i still could not think of a specific counterexample with this conditions, Could anyone help me with this. Thanks


I am using this account. Today morning I have answered a question on Mathematics Stack Exchange. Suddenly my reputation dropped down. What is the reason for this issue? I am totally disappointed.   This week I was scoring nearly 500+ reputations. I lost everything.   Edit: I got a mail like below.     Hello,      I'm writing in reference to your Mathematics Stack Exchange account:            Due to clear signs of falsified accounts being used to artificially   inflate your reputation, your account has been temporarily suspended   for 7 days.      It is not fair to other users of Mathematics Stack Exchange to allow   users to gain reputation through sockpuppets.      The offending accounts have been removed and the votes invalidated.   Please refrain from this behavior in the future.      Regards, Mathematics Stack Exchange Moderation Team


Active Directory DNS and Forest Root Domains

I am a little confused on the proper active directory configurations for the forest root domain. Recommendations call for using corp.example.com or internal.example.com. However, what is the best practice if you own/manage example.com domain? (I own and manage example.com through PowWeb, a web hosting provider).   I want to be able to set up Exchange servers, Web Servers, and FTP servers within the internal (or Corp) network that will be accessible over the internet.   EDIT RELATED QUESTION: Let's say that I decide to use example.com as the root/forest domain in dcpromo.exe. Could I then create a domain corp.example.com, and have the same server that I ran dcpromo on join the corp.example.com domain?  Ultimately, my goal here is to have dcpromo create example.com in its DNS. If I make the root domain in the wizard corp.example.com, it won't create any entries in DNS for example.com.  NOTE: This would be the PRIMARY and FIRST domain controller in the network.


Is there an application search application like the Ubuntu dash or Windows start menu where I can insert an application name, press ENTER and then, the searched application will be opened? It should be fast, reliable, easy to access and also work fine on netbooks.


Does this choice require Axiom of Choice?

This theorem is from Munkres Topology 2nd ed.:       In the last para, it is said that 'choose an element' $n$ of $D$. Why we do not need axiom of choice here? (Here $D$ may not be finite.)


Determine all the prime ideals of $\Bbb Z[x]$ (maybe a different method)

I know that there are quite many questions about the prime ideals of $\Bbb Z[x]$ on MSE. Actually I meet an exercise on this (in the book "Algebra: Fields and Galois Theory" by Falko Lorenz, Exercise 5.12) and the author outline an approach as follows:  (a) For every prime number $p$ and every normalized (that is, "monic") $f$ $\in$ $\Bbb Z[x]$ whose image $\bar f$ is irreducible in $\Bbb F_p[x]$, the ideal ($p$, $f$) is a maximal ideal of $\Bbb Z[x]$. (b) If $P$ is a prime ideal of $\Bbb Z[x]$ that is not of the form given in (a), $P$ is a principal ideal of $\Bbb Z[x]$. If $P$ is a principal ideal of $\Bbb Z[x]$, then $P$ is not a maximal ideal.  I have done by myself (a). For (b), I reduce it into two cases depending on whether $P$ is principal. I also show that if $P$ is principal, then $P$ is not maximal. So where I get confused is the case when $P$ is not principal. I can't reach a contradiction if I further suppose $P$ is prime but not the one in (a). Any ideas or hints?


Cite articles "in preparation" or conference presentations in post-doc/junior positions grant application

There are already questions on how to handle unpublished material in CVs. But here I am wondering if would be reasonable to cite an article in preparation in the application of a grant for a PhD or a postdoc position right after a PhD. So basically only for Junior scientists  who are still  in the process of finishing their PhD or their Masters and have one or two papers in the pipeline which are very relevant to the application in question.  I have seen published papers citing  other manuscripts in preparation, usually from the same author or a co-author. So how is this handled/seen in a grant application, provided that the manuscript in preparation exist and can be  provided if requested? Would it be better to reference a presentation at an international well-known conference?


How does a (static) magnetic field accelerate objects (like an iron nail) if we are taught that the magnetic force does always zero work?


Use Google instead of Bing with Windows 10 search

I want to use Google Chrome and Google search instead of Bing when I search in Windows 10.   Google Chrome is launched when I click on web, but it's Bing search. (My default search engine on Google and Edge is )    I haven't found how to configure that.  Someone can help me ?


I'll go direct to the point: I'm using Haskell to calculate the numbers that I want, these numbers always have some millions of digits (usually more than 15 million digits) and I'm throwing them into separately ".txt" files. How can I get the number from the file and use it with text formatting and etc? Basically it's use what is inside the file (one line only with the huge number, no extra lines)


Prove that the limit of a sequence is 0. (Stolz-Cesaro theorem?)

Prove that if $(a_{n+1} + a_n) \to 0$, then $\frac{a_n}{n} \to 0$. Is it possible to replace $0$ by some $g$?  It looks like using Stolz-Cesaro theorem is required here but I don't really have any ideas on how to start.


$M \times N$ orientable iff both $M$ and $N$ are orientable proof in terms of volume forms

I'm studying differential forms, and in my homework I'm asked to show that the product of two manifolds $M \times N$ is orientable if and only if both $M$ and $N$ are orientable.  I want to show this using volume forms. For the backwards implication ($\Leftarrow$):  Suppose $M$, m-manifold, and $N$, n-manifold, are orientable. Then there exist nowhere vanishing top forms $\omega_1 \in \Omega^m(M)$ and $\omega_2 \in \Omega^n(N)$. Define $\omega_1 \times \omega_2$ in $M \times N$ by $\omega_1 \times \omega_2(X_1,...,X_m,Y_1,...,Y_n)=\omega_1(X_1,...,X_m)\omega_2(Y_1,...,Y_n)$, and one can easily see that this is a form, a top, nowhere vanishing $(m+n)$-form in $M\times N$. It follows that $M\times N$ is orientable.  My problem is in the forward implication. How do I show that if $M\times N$ is orientable, then so are $M$ and $N$, or, equivalently, if $M$ and $N$ are both not orientable, then $M\times N$ can't be orientable? How can I construct volume forms on $M$ and $N$ from a given volume form in $M\times N$?


I would like to texture a window frame that is part of a wall. Whenever I try texturing the window frame the wall gets textured with it. I want to texture the window frame without texturing the wall. I tried:   Selecting the window frame. Clicking the + icon at the right side of the material properties. Here is where I get stuck: I cannot give the new material a color. I would have to click the New button to do that but that is not mentioned in the solution.   I am using Blender version 2.82a. Any help would be appreciated. Thanks.


How do people calculate proportions of dark matter, dark energy and baryonic matter of the universe?

The Wikipedia page on  mentions that the Planck mission had revealed that in our universe ordinary baryonic matter, dark matter and dark energy are present in the ratio: 4.9%, 26.8% and 68.3% respectively. I do not understand exactly how this result had been got. Did the Planck mission scan the entire universe as it is today to get these figures or just a part of the universe? (Is it really possible to scan the entire universe if the universe is infinitely large?) Can anybody please explain the principle behind the calculation?  I also notice that the above figures are given in terms of percentages. Can I get the absolute values of the individual quantities like, total dark energy = .... Joule in the universe?  In case only a part had been scanned then is it possible that in future these figures may change if a larger portion of the universe is scanned by another mission?


Are quotients of chain groups $C_n(X)/C_n(A)$ still free?

Suppose you have a topological space $X$ and a subspace $A$. Their chain complexes are made up of free abelian groups $C_n(X)$ and $C_n(A)$ are the free abelian groups on the $n$-simplexes on $X$ and $A$, respectively.   If we take the quotient complex we get another chain $$ \cdots\to C_2(X)/C_2(A)\to C_1(X)/C_1(A)\to C_0(X)/C_0(A)\to\cdots $$ of abelian groups.   Are these quotients still free abelian groups though? I know in general that the quotient of a free abelian need not be free, but is it any different in this case however?