Using @ signs in comments without invoking comment replies?

How can I put the @ sign in a comment without referring to a person?   I want to have six @ characters in a comment (ruby on rails variables), but when I try to do this, I'm getting an error about being unable to notify that many people in a single comment.  It seems that the workaround &#64; is not being replaced with an @ sign, either.


Binomial math symbol like but with square braces

I want to generate symbol like this:    But I can't find a proper method in LyX. I tried frame decoration with \overset like this:    I also tried square braces with matrix inside, but is too large. It's surprising that LyX doesn't offer equal size room inside "frame decorations". How can I do here?


Can food make you put on more weight than it's own weight?

We all know that about 3500 calories is equivalent to 1 pound (7500 cals for 1kg).  So can a piece of food weighing one pound have more than 3500 calories?  What are the highest and lowest energy dense foods? and will consuming the former make you less full while the latter make you feel fuller for less calories? or do the calories consumed cause you to feel full?  Is there a limit to how many calories can be in 1 pound of food (including artificially made "foods")?


How to increase downloading speed in ubuntu 20.04?

Can anyone help me out by suggesting any good software or any other way to increase downloading speed for files downloaded through firefox.


Exercise: Show that $d(x,y)= \left|\frac{1}{x} - \frac{1}{y}\right|$ defines a metric on $(0,\infty)$.  What I've tried: I need to check the following properties   i) $0\leq d(x,y)<\infty,$ for all $x,y\in(0,\infty)$.  ii) $d(x,y)=0$ if and only if $x=y$ iii) $d(x,y)=d(y,x),$ for all $x,y\in(0,\infty)$.  iv) $d(x,z)\leq d(x,y) + d(y,z)$ for all $x,y,z\in(0,\infty)$.   I think I was able to solve the first three properties  i): If $\dfrac{1}{x} - \dfrac{1}{y}$ is positive then $d(x,y)$ is positive, if $\dfrac{1}{x} - \dfrac{1}{y}$ is negative then $d(x,y) = \left|\dfrac{1}{x} - \dfrac{1}{y}\right|$ is positive, so $d(x,y)\geq 0$. Since $x,y\in(0,\infty)$ we have that $\left|\dfrac{1}{x} - \dfrac{1}{y}\right|\in(0,\infty)$.  ii): If $x = y$ then $d(x,y) = 0$, if $x\neq y$ then $\dfrac{1}{x} \neq \dfrac{1}{y}$ and $d(x,y) \neq 0$.  iii): If $\left|\dfrac{1}{x} - \dfrac{1}{y}\right|^2 = \left|\dfrac{1}{y} - \dfrac{1}{x}\right|^2$ then $\left|\dfrac{1}{x} - \dfrac{1}{y}\right| = \left|\dfrac{1}{y} - \dfrac{1}{x}\right|$. I know that $\left|\dfrac{1}{x} - \dfrac{1}{y}\right|^2 = 1/x^2 - 2/xy + 1/y^2 = \left|\dfrac{1}{y} - \dfrac{1}{x}\right|^2,$ hence $\left|\dfrac{1}{x} - \dfrac{1}{y}\right| = \left|\dfrac{1}{y} - \dfrac{1}{x}\right|^2$ and $d(x,y) = d(y,x)$.  I don't know how I should show that the fourth property holds!  Question: How do I show that $\left|\dfrac{1}{x} - \dfrac{1}{y}\right|\leq \left|\dfrac{1}{x} - \dfrac{1}{z}\right| + \left|\dfrac{1}{z} - \dfrac{1}{y}\right|$, or equivalently, that $d(x,y) \leq d(x,z) + d(z,y)$?  Thanks!


Voltage Follower Not Giving Expected Output

Have set up a voltage divider inputting 1 volt into a LM741 op amp to act as a voltage follower. For some reason I get 2 volts at the output. Have checked everything I can think of and can’t figure out why.


Cannot award bounty less then previous bounty

I have tried setting a bounty on a question:    Originally set to 400.  Unfortunately I was not able to award it before it exprired.  I understand that I can't get the reputation back, which is not an issue.  The thing is that I can only award bounty that is higher then the one I tried awarding before, so the only bounty I can offer after the previous one expired, so the only bounty I can award now is 500 rep points.  This seems a little odd to me since I might just re-award the same rep amount or possibly less depending on the quality of the answers but the system doesn't allow me to.  Can someone clarify this point?


I would like to calculate a buffer of 5km around country polygons. However, I somehow always get a warning and an error. Here is a reproducible example code.   library(sp) library(sf) library(tmap)  library(rnaturalearth) countries_sp <- ne_countries(scale = 10)  countries_sp <- countries_sp[(countries_sp@data$geounit %in% "France"), ]  proj4string(countries_sp) <- CRS("+init=epsg:4326")   countries_for_buff <- st_as_sf(countries_sp, crs ="+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m +no_defs ")  countries_buff_5km <- st_buffer( countries_for_buff, 5000)   here the warning:  dist is assumed to be in decimal degrees (arc_degrees). Warning message: In st_buffer.sfc(st_geometry(x), dist, nQuadSegs, endCapStyle = endCapStyle,  : st_buffer does not correctly buffer longitude/latitude data   Then   tm_shape(countries_sp) +   tm_polygons() + tm_shape(countries_buff_5km) +   tm_polygons()   gives the error   Error in if (all(tiny) && show.messages) warning("all relative area sizes are below thres.poly",  :     missing value where TRUE/FALSE needed   What am I doing wrong? I guess there is something about the projection that does not quite work out the way it should.


So i am playing in a high level game where i am playing a 13th level Storm sorcerer multiclassed with a 2nd level Tempest Cleric. At the end of the last session we levelled up and I am taking a 14th level in Sorcerer.   Now, as a 16th level caster, I have 8th level spell slots. Under “Spells known of 1st level and higher” it says that           ... you learn more sorcerer spells of your choice. Each of these spells must be of a level for which you have spell slots      Does this mean that i can choose 8th level sorcerer spells? Has this been clarified anywhere?   I am aware of the discussions around wizards copying in higher level spells but the argument there seems to resolve around the fact that they could probably copy them into their book, but would be unable to prepare them. Sorcerers do not prepare spells and so it is a different question.  Many thanks guys!


Does the recurring succession $X_{n+1} = 1+\frac{1}{X_n}$ converge?

I'm working on some calculus exercises and came across this one. It is familiar yet not the same as the $\mathcal e$ one. The question states:  Given $X_0 = 1$ and $X_{n+1} = 1+\frac{1}{X_n}$, for $n \geq 0$.  Show that it converges and find its limit.     So I tried to approach this by looking at its behave. Does $\frac{1}{X_n}$ converge to $0$ ? But it's not trivial answer. I also tried to look at $X_{n+1} $ expressed as a function of $X_0$ but was hard to see if I could simplify it in one-line formula. Any ideas?


Get all parameters and their values in a request in Django

I have a get request being sent to my Django project with a list of parameters. GET /site/login? _name=bill&_last_name=Smith&_favorite_food=wings  I need to get each parameter and it's value.  What would be the best way to do this?  I know that in Django you can do print(request.data) but I need the parameters.


Recently, I was wondering how division of aleph numbers would work. First, I thought about how finite cardinality division would work. What I came up with was that the result of $A/B$ where $A$ and $B$ are both cardinalities, is the number of times that each element of $B$ had to be mapped to an element of $A$ in order to ensure that all elements of $A$ were mapped to.  Extending this to aleph numbers, specifically, I thought that $\aleph_1/\aleph_0$ would be $\aleph_1$. The reasoning behind this is that there are an infinite ($\aleph_1$) number of real numbers between any two natural numbers. As such, that mapping would need to be applied.  Can anyone validate this idea? Is this how division of aleph numbers actually works, or am I totally off base?  Thanks.


I'm trying to write a paper using RevTex 4.1 and natbib 8.31b, and the .bib file is not being recognized.  My paper is:  \documentclass[aip,reprint]{revtex4-1} \usepackage{amsmath}    % need for subequations \usepackage{graphicx}   % need for figures \usepackage{natbib} ... \begin{document} \bibliographystyle{plainnat} ... {Text of document} % Create the reference section using BibTeX: %\bibpliographystyle{aipauth4-1} \bibliography{References} \end{document}   and my .bib file (excerpt) is:  @article{AharonovBohn1959// ,title = "Significance of Electromagnetic Potentials in Quantum Theory"// ,author = "Y. Aharonov and D. Bohm" ,journal = "The Physical Review" ,pages = "485-491" ,year = 1959 }  @article{vanOudenaardenDevoretetal1998 ,title = "Matneto-electric Aharonov-Bohm effect in metal rings" ,author = "A. van Oudenaarden, M. H. Devoret, Y. V. Nazarov & J. E. Mooij" ,journal = "Nature" ,pages = "768-770" ,year = 1998 } ... etc.   When I run pdfLaTex in TeXworks the paper compiles fine with no errors or warnings.  When I then run BibTeX I again get no errors or warnings, but when I run pdfLaTeX again I get:  This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013/W32TeX)  restricted \write18 enabled. entering extended mode (./PhysicsFromFrequencyV1-1.tex LaTeX2e <2011/06/27> ...  Package natbib Warning: Citation `AharonovBohn1959' on page 4 undefined on input line 305.  Package natbib Warning: Citation `vanOudenaardenDevoretetal1998' on page 4 undefined on input line 305.   Running pdfLaTeX multiple times does not resolve this error.  It seems like natbib is not seeing the References.bib file, but I don't know what else to do to connect the two together.  Does anyone have any advice about what I'm doing wrong?


What to make of the following sentences that begin with why, when, where, or how?

Why you put yourself in this predicament is beyond me.   When you leave for work is of your concern.   Where we spend the night depends on the weather.   How you finish the project is unimportant.      I feel they are relative adverbs (fused) or free nominal constructions. But I fear I'm completely off.


Downloading LASTools on Windows 10, QGIS 2.18.24 - Error Message

Following the instructions on this page;   I came across this error when I tried to define the path to my LASTools folder in the QGIS Processing Toolbox Menu [C:\Lastools]    Please could anyone explain to me how I can fix this error?


Difference between the use of "for" and "of"

I am always confused by the difference between the use of for and of in cases like these:        Principal component analysis of microarray data.   Principal component analysis for microarray data.      Which of these is correct? Is it OK to use both? If yes, when should I use 1. and 2., respectively?


Performance difference between toString() and +""

Is there any advantage or disadvantage between doing    var a = b.toString()   or  var a = b+""   from performance wise? Both works and serve the same purpose. We can think of doing it on for example a billion of strings.


Is this man in middle atack possible in quantum cryptography?

Lets consider there is channel between Alice and Bob, sequered with quantum cryptography.  To put it simple, Alice is left, Bob  is right  and the quantum states are 'up'  ~ U and 'down'  ~ D.  Alice and Bob generates pair of bounded particles ,always one u one d but you dont know wtigth one flyes left or right , what fly always in both direction. Also they can capture particles. If captured, a particle is destroyed.   Alice captures the particle what flyes left and sends free what flyes to the right, Bob does the mirrored. If anyone captures the particle, he would know that other particle of the pair is.   Lets consider the MiM attacker Eve, what can do like Alice and Bob do.  Eve captures the next particle send by Alice, let it be U. So she knows, that the particle what Alice captured locally was D. But the particle U is destroyed, Bob will know that way, that there is something wrong with the channel.   Important : Eve then generates own particles, while capturing the left one.  If the captured is D, Eve knows that the pair is U and it might be send further to Bob. In the model that there are only 2 states, the probability of producing the right pair is 50% , therefore Eve in average need to be capable to generate and send particles twice faster that Alice and Bob do, that generally fair possible practicly.  Alice can not distinguish between cases whether a sent particle was captured by Bob or Eve, neither Bob can distinguish,  because the quantum features of particles match.  Later Eve can, as usually in MiM take over a channel and start to send false data to them.  Is there something wrong it this szenario or generaly quantum cryptography is a big talk about nothing?


Search for all chat messages by a particular user?

Is it possible to search for all messages by a particular user in the chat search, at ? I tried searching with the 'search for' field empty, but got no results... and with '*', the same.


Can't the account information on my checks be easily used for fraud?

My Bank of America checks contain my routing & account number, which I've used in the past to make purchases online, among other things. Anyone whom I pay with a check has this information. It seems like this account info is even more sensitive than my credit card #, since with Visa I am protected with a Zero Liability policy, but I do not know that to be the case for my checking account.  I may be naive, but there's a lot of people I've paid with checks whom I would never give my credit card (e.g. people I've bought from on Craigslist). I'm now wondering if it's irrational to do this.


In order to center stuff in math mode, we can use either $$...$$ or \[...\].  Is there an OBJECTIVE reason as to why one is better than the other?


How to transfer a Terraria PC map to Xbox One?

I've looked around, and do not see a place in my Xbox One to look at specific files, so I have no clue how to drop maps onto my external drive to play Terraria on.  Background info: I bought an Xbox One for myself for Christmas, and it came with a 350gb hard drive and some of the smallest games take like 10gbs to download so I bought a 4tb drive for 100 dollars, much less than they wanted for a much smaller internal Xbox One drive by the way.  So how do I get a Terraria map from my PC onto my external drive, to play it on my Xbox? I've seen some kids on YouTube bragging about an all items map, but they don't show how to drop the map (transfer it from PC to Xbox).  So what do I do?


Is there a black hole in the centre of the Milky Way?

Is it true that the whole galaxy is actually revolving, and powered by a black hole?  Has it been proven, and if it is true, how can our solar systems actually keep up the momentum to withstand the pull?


raggedright table paragraph with array package gives me error message, what am I doing wrong?

Consider the following:  \documentclass{memoir} \usepackage{array} \begin{document} \begin{tabular}{l>{\raggedright}p{0.45\textwidth}}         foo   & bar  \\         one   & two  \\         three & four \\ \end{tabular} \end{document}   It gives me the following error message:  ! Extra alignment tab has been changed to \cr. <recently read> \endtemplate   l.6         one   &                     two  \\ ?    Clearly I am doing something wrong but I just can't figure it out. Can someone explain it to me?


I  and a user was rude to me in a comment and in an answer. Even though I can't downvote, that answer got -5 and it was automatically deleted. I want to complain about that user. How can I do that?


I have:   /home/user/my_static /home/user/static/   How do I rename my_static to static and remove static(2)?


Why is stackexchange so brutally biased against casual users?

I registered years ago. It's super annoying that you can't do anything without "reputation". You can't comment. Can't answer questions. Even worse the reputation is separate by different stackexchange sites...  Since I'm not a question or answer spammer. This cements me to never being able to comment on anything and being able to answer questions which require some reputation. I can't even vote. I can't do anything useful outside asking my own questions, to be honest.  Many times I would have like to be able to comment on an answer. (To add to it, or to ask for some clarification) Of course I can't. And won't ever be able to.


Can I use cement backer board as a subfloor?

Would it be correct to tack  to the floor joists directly or is it necessary to lay exterior plywood when renovating/installing a new bath floor? my home is 140 years old and the floor joists are massive. My fear is that the plywood will attract termites as I have had issues with them attracted and devouring new wood used in the house and they have cost me thousands in damages.  The old wood is generally left untouched by the termites since it is old growth cypress.


Consider the rationals $\mathbb{Q}$ viewed as group under addition and let $G=\mathbb{Q}/\mathbb{Z}$ where $ \mathbb{Z} \;\triangleleft \; \mathbb{Q}$  A) What is order of $\frac{3}{5}$  B) Show that G has a cyclic subgroup of order n for each $n>1$  Please help to solve this problem i really stuck


Can silicon droplets bouncing on a vibrating surface be a model for Quantum Mechanics?

In       it is claimed that silicon droplets bouncing on a vibrating surface show behaviour in analogy to particle/wave duality in Quantum Mechanics.   Is this true? Did they really reproduce the double slit experiment (the video doesn't show that)? And what happens to the silicon droplets on a single slit? What about Quantum tunneling? Which effects of Quantum Mechanic can be "emulated" with bouncing silicon droplets and which can't?


Extension to the Airplane Probability Problem

Can someone explain the answer to this question:  'Imagine there are a 100 people in line to board a plane that seats 100. The first person in line realizes he lost his boarding pass so when he boards he decides to take a random seat instead. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead.  Question: What is the probability that the last person that boards will end up in his/her proper seat.'  If instead of only the first person having lost their ticket the first two people have lost their tickets and take random seats?


I have this question and I'd like an idea to solve it:  If $Z_p(X,Y)=\lbrace \sigma\in C_p(X), \partial\sigma\in C_{p-1}(Y)\rbrace$,  $1)$prove that $H_p(X,Y)$ is isomorphic to $Z_p(X,Y)/(B_p(X)+C_p(Y))$,  $2)$ deduce that $H_0(X,Y)$ is the free module generated by the path connected components of $X$ that do not contain points of $Y$  $Z_p(X,Y)=\ker(\partial_p: C_p(X,Y)\rightarrow C_{p-1}(X,Y))$ $B_p(X,Y)=Im(\partial_{p+1}:C_{p+1}(X,Y)\rightarrow C_p(X,Y))$  $C_p(X,Y)=C_p(X)/C_p(Y)$  $H_p(X,Y)=Z_p(X,Y)/B_p(X,Y)$  Please help me   Thank you.


Why is the ticket from an airport further away half the cost?

I am looking to go to the USA for a week or so in March and I have just noticed that flights from Dublin (that go via Heathrow) are half the price or less than the same flight directly from Heathrow.   Any idea why this is? I think I will catch a cheap flight to Dublin and add a couple of hours to the journey - I will save over £1000 for the 2 of us!!


Possible Duplicate:          I installed the IE10 beta on Windows 7. It has an annoying autocorrect feature like the one in MS Word that messes up everything I write. How do I disable it?


Which share icon is most appropriate for web?

Now days there are multiple viable share icons available, but they are mostly mobile OS specific (iOS, WP, Android...). I wonder which icon should I use for the web that most of the users would recognize?    Image source:   Has anyone done any A/B tests on how users respond to different ones?   Its a simple album page where you can get links for each album/image and then share it with a friend, nothing special, just popup on click of an icon.


How to avoid NullPointerException in a Fragment with a delayed Runnable

I have an app with 5 tabs, 3 are the same fragment and two are two different fragments. This problem happens in all 5 fragments since the code is the same.  When I click the tabs really fast and there's some text in my AutoCompleteTextView, the app crashes.  I've tried to check if my components (listAdapter and ArrayAdapter) are not null before asigning or initializing them.  override fun afterTextChanged(s: Editable?) {             val db = DataBaseHandler(context)             var listAdapter: ArrayAdapter<String>              Handler().postDelayed({                 search = etSearch.text.toString().trim()                 if (search.length >= 3){                     resultList.clear()                     products = if (isNumeric(search)) db.readData_SomeProductsId(search)                         else db.readData_SomeProductsDesc(search)                     for (product in products!!)                         resultList.add(product.prod_description)                     if (resultList.size == 1){                         product = products!![0]                         ETClear(etSearch)                         addProduct()                     } else{                         if (resultList.size > 1){                             listAdapter = ArrayAdapter(context, android.R.layout.simple_spinner_dropdown_item, resultList)                             etSearch.setAdapter(listAdapter)                             etSearch.showDropDown()                         }                      }                 }             }, 600)              etSearch.setOnItemClickListener{ parent,view,position,id->                 val selectedItem = parent.getItemAtPosition(position).toString()                 product = db.readData_ProductDescription(selectedItem)!!                 ETClear(etSearch)                 addProduct()             }         }   The error shows as follows:  06-05 18:01:49.034 26859-26859/com.example.said.puntodeventa E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.said.puntodeventa, PID: 26859 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference     at android.view.LayoutInflater.from(LayoutInflater.java:234)     at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:178)     at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:163)     at com.example.said.puntodeventa.SaleFragment1$onViewCreated$1$afterTextChanged$1.run(SaleFragment1.kt:109)     at android.os.Handler.handleCallback(Handler.java:739)     at android.os.Handler.dispatchMessage(Handler.java:95)     at android.os.Looper.loop(Looper.java:158)     at android.app.ActivityThread.main(ActivityThread.java:7231)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)   Thanks in advance


I've downloaded the SVG icon pack from   Using the Import from URL has never worked for me, so how do I import these symbols into QGIS?   As far as I can tell I need an .XML defining each symbol.


I read some resources about the mount command for mounting devices on Linux, but none of them is clear enough (at least for me).  On the whole this what most guides state:  $ mount (lists all currently mounted devices)  $ mount -t type device directory (mounts that device)  for example (to mount a USB drive): $ mount -t vfat /dev/sdb1 /media/disk   What's not clear to me:   How do I know what to use for "device" as in $ mount -t type device directory? That is, how do I know that I should use "/dev/sdb1" in this command $ mount -t vfat /dev/sdb1 /media/disk to mount my USB drive? what does the "-t" parameter define here? type?   I read the man page ($ man mount) a couple of times, but I am still probably missing something. Please clarify.


How does the melting ice cube in a glass of water doesn't change the water volume?

that's problably a very noob question, and answer that i found is: the water volume was always the same, what is kinda obivius, but doesn't seen enought to me. So I can't stop thinking, were did the extra ice volume above the water line goes, I had a tought, and a wanna know if it makes any sense.  Is that volume above the water line, exactly the air volume inside the whole ice cube that will be lose during the melting?


Is this Tabaxi Monk/Barbarian/Rogue/Fighter movement speed calculation accurate?

Dash is an action that can be taken by any character, and by some as a bonus action, and Tabaxi's racial feature feline agility can be used as part of their movement, not action or bonus action.  So a tabaxi's base speed is 30'. Assume my character is a 10th-level monk (+20' speed), a 6th-level Barbarian (+10' speed from fast movement), a 2nd-level Rogue (with the cunning action feature), a 2nd-level Fighter (with the action surge feature), and has the mobile feat (+10' speed).  This allows a speed of 70'. a partner casts longstrider on me (+10' speed), so my speed is 80'.  The tabaxi feline agility feature is: "when you move on your turn during combat, you can double your speed until the end of the turn, cannot be used again until you move 0".  Assuming I need to run - while in combat:   Base speed 80' feline agility "when you move on your turn during combat, double speed" now speed 160' action drink potion of speed (gain an additional action, doubles movement) notice this does not double again, as an effect that already doubles my speed is in effect haste action dash +160 action surge dash +160 bonus action dash (cunning action) +160  = 640 feet   Now the next turn, I couldn't use feline agility, nor action surge, but would free up an Action, and the haste spell effect would double my speed.   Recalculating this, base movement 80 potion of speed in effect x2 (160) haste action dash +160 (320) action dash +160 (480) bonus action dash (cunning action) +160 (640)  = 640   As I understand it, if an effect would be repeated through use of item/magical means, they do not stack.  In this case the "Doubles your movement" is the effect in question, as it is repeated through many means (spell, potions, racial abilities, and even boots) it only makes sense that it is not permitted to stack, but please, correct me if I am wrong.


Remove line with the pattern match and the next line

I am trying to remove all instances of a pattern match from a file if it matches a pattern. If there is a match, the (complete) line with the matching pattern and the next line get removed.   The next line always appears after the line with the pattern match, but in addition it appears in other areas of the file.  I am using grep and it is deleting all occurrences of the next line in the file, as expected.  Is there a way I can remove that next line if and only if it is after the line with the pattern match?


Error Message: It looks like your post is mostly code; please add some more details

How do you solve the following error when creating a simple post?     It looks like your post is mostly code; please add some more details


When using Spring Security, what is the proper way to obtain current username (i.e. SecurityContext) information in a bean?

I have a Spring MVC web app which uses Spring Security.  I want to know the username of the currently logged in user.  I'm using the code snippet given below .  Is this the accepted way?    I don't like having a call to a static method inside this controller - that defeats the whole purpose of Spring, IMHO.  Is there a way to configure the app to have the current SecurityContext, or current Authentication, injected instead?      @RequestMapping(method = RequestMethod.GET)   public ModelAndView showResults(final HttpServletRequest request...) {     final String currentUser = SecurityContextHolder.getContext().getAuthentication().getName();     ...   }


Q: what book on Bayesian statistics, preferably with R?

I am frequentist by training and practice, but I'd like to learn more about Bayesian statistics. I know the basics, but I would be at a loss if I had to, for example, replace my normal ANOVA hypothesis testing approach with a Bayesian alternative.  What book would you recommend to learn practical Bayesian approaches? Preferably using R.


Execute a command and put the results into a variable... all in a bash script

I'm working on a bash script that backs up a configuration file before copying over a new file.  Here's what my snippet looks like:  mv ~/myStuff.conf  ~/myStuff.conf.bak cp ~/new/myStuff.conf ~/myStuff.conf   Every time this script is run, I'd like there the backup to have a unix timestamp in the filename.  I tried this  DATEVAR=date +%s mv ~/myStuff.conf  ~/myStuff.conf.$DATEVAR.bak   But this doesn't work, since the date function doesn't execute and bash sees it as a string, and the resulting file ends up being  myStuff.conf.date+%s.bak   Any ideas on how to get the results of the date function into a variable?


Hi I am doing an ipa and was wondering if 14 days in the primary is to long before racking to a secondary for dry hopping. I see others saying 7 days in the primary then 14 days in the secondary.


On trying to edit a comment after the 5 minute grace period, I get an error message of the form Error editing  comment : write_failed. I wasn't able to get a screenshot as it was visible for only a few seconds.   This should be replaced with the a proper pop-up stating "Comments cannot be edited after 5 minutes of posting" like in the case of the full site.  Version : 0.1.18  Update  Here is a screenshot of the error message. I'm on version 0.1.31


SEO for Google: navigation, company info, video

I often stumble upon search results in Google that get a special treatment, like:   having the site navigation (and more) being displayed on the search results page  having a company's location, contact information, Google reviews and e.g. opening hours being displayed aside the search results  having a video thumbnail being displayed with the search result and the navigation structure being displayed instead of the blank URL (giga.de > Deals)    I'm building a website for my (nationally pretty well known) choir but have not been into search engine optimization, yet. There's many blogs and documents on that topic. But what I want is that special behavior described above. Can you tell me how I can reach that? Or are there any documents that deal with these (and more?) special Google features?


Designing in proprotion for Flex Printing

I want to design a flex banner of (90 Feet X 4 Feet) @ 72dpi. But i cant open a work book of such size in Illustrator. Can you please guide me on how to design the banner using the idea of a sizing the design in proportionality.  Thank you


guys very simple question here.  I'm writing a paper on elliptic curves, and the domain of the function has this extra point which is referred to as "a point at infinity."  It looks like this :  I have no clue what the shortcut is for that.  I've just been using the letter O instead.  Anyone know what that symbol is?  Appreciate the help!


Is the Speed of Light an universal spacetime constant, the velocity of electromagnetic waves, or of photons?

This question has been touched tangentially by  and  but I do not think they reach the core of my question.  When I read that many other theories, e.g. the Standard Model, have been constructed to be Lorentz invariant it appears that electromagnetism has some of preponderant role in the universe compared to other theories. I suspect that the answer is that this is not the case, and that the space-time Speed of Light (with upper-case) is really more of a universal constant that is not necessarily related to the speed of the electromagnetic waves or of photons.  There are many other related questions:    would it really be devastating for relativity that we find out in the future that photons have a tiny mass and move slower than ... uhh... the speed of light? which "c" is applicable in different situations? I mean, possibly the space-time constant should be used in $E=mc^2\gamma$, it would be the  velocity of gravitational waves, etc..., but in other situations such as the Bohr radius or Compton wavelength I am not sure.   Well, any answer will be appreciated. Please tell me if you know any reference to bibliography that address this issue.


This is happening when you ask questions.     I reproduced this on a different SE website and with the latest versions of Chrome and Firefox


Draw connection between node in forest tree diagram and something outside it

I'm having trouble connecting a node inside of a forest tree diagram with some arbitrary text outside it.    MWE:  \documentclass[12pt,paper=a4]{scrartcl} \usepackage[linguistics]{forest} \usetikzlibrary{positioning}  % cf. http://tex.stackexchange.com/a/1912/60686 \tikzstyle{na} = [shape=rectangle,inner sep=0pt,text depth=0pt]  \begin{document}  \begin{forest} [A, name=A     [B]     [C         [X, name=X]         [Y]     ] ] \draw[-latex,dotted] (A) to[out=west,in=west] (X); \end{forest}  \tikzstyle{every picture}+=[remember picture] \tikz\node[na](lorem){Lorem}; ipsum \tikz\node[na](abc){dolor}; sit \tikz\node[na](amet){amet};.  \begin{tikzpicture}[overlay]     \draw (X) to (abc);     \draw[-latex] (lorem) to[out=south,in=south] (amet); \end{tikzpicture}  \end{document}     The result of the above code unfortunately looks like this:    In other words, tikz can't seem to find the node X, so the line just trails off to nowhere instead of connecting the X node to the abc node. In order to demonstrate that connecting things works inside of either the diagram or the text, I drew a bunch of arrows there as well.  Putting the line \tikzstyle{every picture}+=[remember picture] above \begin{forest} causes the various content boxes and drawings to appear all on different pages.


Add a column with a default value to an existing table in SQL Server

How can I add a column with a default value to an existing table in  / ?


Using the division algorithm, find the greatest common divisor of $x^4+x+1$ and $x^3+2$ in $\mathbb{Q}[x]$ and express it as a linear combination of these polynomials.  So far the division has given me that:  \begin{align*} x^4+x+1&=x(x^3+2)+(1-x)\\ x^3+2&=(-x^2-x-1)(1-x)+3\\ 1-x&=-\frac{1}{3}x+\frac{1}{3} \end{align*} and of course that $\gcd\left(f(x),\,g(x)\right)=1$.  I'm not entirely sure how to proceed or how to represent these as linear combinations.


apt held packages, can't install package

On Ubuntu 12.10 when trying   sudo apt-get install mono-complete   to install mono, I get:  enter codReading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  mono-complete : Depends: mono-devel (= 2.10.8.1-5ubuntu1) but it is not going to be installed                  Depends: libmono-cil-dev (= 2.10.8.1-5ubuntu1) but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I tried removing mono-devel and libmono-cil-dev but they are not installed.  I've tried   sudo apt-get clean && apt-get update && apt-get upgrade   but it does not help.   dpkg --get-selections | grep hold   does not give any results, so it seems that no packages are actually held.  I've also tried  dpkg --configure -a   and   apt-get install -f   neither of which helped either.  Strangely though, I do have mono installed in /usr/bin/mono. The way that I got into this mess was that I tried to get the latest versions by following the directions here: . apt-get was complaining about held packages at which point I did   sudo apt-get dist-upgrade   I don't know if that was the cause of my current problems. Anyway, after it continued to complain about packages being held, I removed that experimental mono deb source from my sources and removed mono-complete, and ran apt-get clean, update, and upgrade, to get back the blank slate. At that point, I tried to install mono-complete from a blank slate, and arrived to my current situation.  EDIT:  $ apt-cache policy mono-devel libmono-cil-dev mono-devel:   Installed: (none)   Candidate: 2.10.8.1-5ubuntu1   Version table:      2.10.8.1-5ubuntu1 0         500 http://us.archive.ubuntu.com/ubuntu/ quantal/main i386 Packages         100 /var/lib/dpkg/status libmono-cil-dev:   Installed: (none)   Candidate: 2.10.8.1-5ubuntu1   Version table:      2.10.8.1-5ubuntu1 0         500 http://us.archive.ubuntu.com/ubuntu/ quantal/main i386 Packages   @meebey of the linked experimental page recommends apt-get remove cli-common for a full mono removal which outputs this:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  mono-xsp4 : Depends: mono-xsp4-base (= 2.10-2.1) but it is not going to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.   RESOLVED I resolved this issue by adding the experimental ppa back and removed mono-complete and cli-common. Then I removed the experimental ppa again which got me back to a blank slate. For that reason I don't consider this a duplicate issue, but it doesn't matter.


I put some alias commands in my .bashrc file, so that they might be loaded everytime I open a new Terminal window. Yet this doesn't happen. I have to select run script: in the Terminal>Preferences>"MyDefaultTheme">Shell prefpane and add: source .bashrc && clear for it to work... This seems odd since many tutorials only say you just have to add to the .bashrc file and all is good. Note that I don't run in bash when using the terminal, I like the other (default) one (don't know what it is) better, because it show me where I am all the time eg: >>d54c6b47b:~ romeo$  in stead of: >>bash$  In bash all is loaded as should be. So my question is, why didn't my .bashrc file load automatically and did I have to add the option to call it everytime? Also some tutorial told me to do something like: $alias la=’ls -la’ >> ~/.bashrc  which should write the alias to my .bashrc, this doesn't work either... Note that I'm a UNIX novice, so be gentle.


Okay, so I am trying to be able to explain the answer to the question below to a friend, but I don't know how. I know that the process method doesn't change s and that the answer is ABCD (s is unchanged), but I don't know why. Is it because strings are immutable? My friend thinks it should be CBA. Any help?  public void process(String s)  {     s = s.substring(2, 3) + s.substring(1, 2) + s.substring(0, 1); }   What is printed as a result of executing the following statements (in a method in the same class)?  String s = “ABCD”; process(s); System.out.println(s);


Why do metamaterials have $n<0$? They are defined to be those materials with $\varepsilon <0$ and $\mu<0$, but the definition of the refractive index is $$n=\sqrt{\frac{\varepsilon\mu}{\varepsilon_0\mu_0}}$$ So it should be still positive.


Do I need a working visa to stay in the US but work for a company in Europe?

Sorry If this seems a silly question but I am 19 and have never delved into anything like this before. I am a software developer and have plans soon  to work remotely as quite a few companies offer this (adhering to their time zone requirements ) and I would quite like to mix work in with travel. What kind of visas / requirements would I need to stay in the United states for say, 6 months to 1 year, and what are my first steps?


I'm looking for an adjective that says "It's cold, but not that cold".  For example, lukewarm means (in my mind) "It's warm, but not that warm", and I'm looking for its cold counterpart.  Every synonym I find for cold describes an increased cold, not a decreased cold.  Is there any word like this?


I'm trying to parse some JSON using the JSon.Net library.  The documentation seems a little sparse and I'm confused as to how to accomplish what I need.  Here is the format for the JSON I need to parse through.  {     "displayFieldName" : "OBJECT_NAME",      "fieldAliases" : {         "OBJECT_NAME" : "OBJECT_NAME",          "OBJECT_TYPE" : "OBJECT_TYPE"     },      "positionType" : "point",      "reference" : {         "id" : 1111     },      "objects" : [ {         "attributes" : {             "OBJECT_NAME" : "test name",              "OBJECT_TYPE" : "test type"         },          "position" : {             "x" : 5,              "y" : 7         }     } ] }   The only data I really need from this is the stuff in the objects array.  Is it possible for me to parse through that with something like the JSonTextReader and just pull out the things I want, like OBJECT_TYPE and the x and y position?  I can't seem to get JSonTextReader to work the way I want it to and I find little to no examples of usage for it.   It seems like serializing first then using LINQ with my object would be ideal and every example I find discusses serializing the JSON first, but I'm not sure how I would build an object for this structure.  Particularly the objects array which would need to be something like a list of Pairs of attribute and position objects.  I have no idea how I would code my object so JSon.Net would know how to serialize that.  I thought I could write my own simple parser to just pull out everything I need into an attributes object that I created, but I'm having little luck.    Hopefully this all makes sense, any ideas?


installing ubuntu 14.04 in dell inspiron 15

Whether it  is possible to choose local disc other  than "c" to install ubuntu in dell inspiron.


Splitting a row with one company in a column and multiple email addresses in other columns

I have data in Excel that looks like this:  column1 column2 column3, column4, column5 Company1 email1 email2 email3 Company2 email1 email2 Company3 email1 email2 email3 email4 email5   I have about 25k rows of this data some maybe 25k companies and 40k email addresses. I'd like to make the data look like this:  Company1 email1 Company1 email2 Company1 email3 Company2 email1 etc.


How shared_ptr detects if it has to call delete[] or delete

I am curious to know, how shared_ptr class decides whether it has to call delete or delete[] for the below statements?  a. boost::shared_ptr <char> ptr(new char);  b. boost::shared_ptr <char []> ptr(new char[100]);


Find $E(\max(X,Y))$ for $X$, $Y$ independent standard normal

Let $X,Y$ independent random variables with $X,Y\sim \mathcal{N}(0,1)$. Let $Z=\max(X,Y)$. I already showed that $F_Z$ of $Z$ suffices $F_Z(z)=F(z)^2$.  Now I need to find $EZ$.  Should I start like this ? $$EZ=\int_{-\infty}^{\infty}\int_{-\infty}^\infty \max(x,y)\frac{1}{\sqrt{2\pi}}e^{-1/2x^2}\frac{1}{\sqrt{2\pi}}e^{-1/2y^2} dxdy$$


If you take the derivative of the volume of a sphere, $$\frac{4}{3}\pi r^3$$you get its surface area, $$4\pi r^2.$$ If you differentiate again, you get $$8 \pi r.$$ Does this have any physical (or other kind of) significance, besides being 4 times the length of a great circle on the sphere?


How to get further elaboration from someone who posted a good solution?

I just posted to request (as a low-rep user; not a high enough rep to comment) for a feature to ask a user on someone else's question, who posted a good solution, for further elaboration. My post was given a lot of criticism. Essentially, everyone deemed the request as abuse of comments. I understand their concerns, but know that others share the same frustration in addition to myself.   All I would like is a way to ask someone who posted a good answer to elaborate further. Because I can't do this, I don't have a solution when there's a great one that's very close to helping me. If I post to ask the same question, that will be marked as a duplicate.   I was on Stack Overflow and somebody posted a snippet of their code showing a great example that would have helped me quite a bit. But the code didn't show the whole picture, and if I could have had him elaborate on what he answered, I would have fixed my issue a while ago.  Nobody has provided a way to get further help, and I've seen so many posts that ask a similar question but haven't found a solution.  So how can I ask someone who posted a good solution to elaborate further?


I'm attempting to create a procedural shadernode to render a radial grid for the top / bottom of the saucer section of the Enterprise, and I'm running into difficulty. My initial instinct is to use the Bricks texture as the primary basis for my shader, as it has the correct combination of large interior spaces separated by solid lines, but I can't quite get it to render in a proper grid pattern on the top of a cylinder (as a test shape) - the most I've manged to achieve is radial lines on the top, by following  answer almost verbatim, but the latitudinal lines elude me. (Edit: Adding a screenshot of wat I've managed to do so far)  Is there some combination of rotating and scaling vectors that I should be looking at? It seems like it would be a relatively common use case... Edit: Somewhat answered by the question , although the math is a bit (a lot) beyond me - the answer seems to be to apply spherical projection to the vector used to project the brick shader. Have yet to make it work, but thank you :)


How to use pagenumbering in the document?

In my Master thesis, I would like to have the title page without any page number and an acknowledgments section and the table of contents with roman numbers. The rest of the document should be numbered arabic.  I have tried this, to have roman numbers for the Table of contents and normal numbers for the rest.  \documentclass[12pt,ngerman,openany]{report} \usepackage{titlesec} \usepackage{titletoc} \usepackage{cite} \usepackage[a4paper]{geometry} %\usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[ngerman]{babel} %\usepackage{ngerman}{babel} \usepackage[T1]{fontenc} \usepackage{graphicx} \usepackage{float} \selectlanguage{ngerman} \usepackage{amssymb} \usepackage{amsmath} \usepackage{url} \usepackage{epstopdf} \usepackage{scrhack} \usepackage{listings} \usepackage{caption} \titleformat{\chapter}{\rmfamily\huge}{\textbf\thechapter.}{25pt}{\huge\textbf} \defcaptionname{ngerman}{\lstlistingname}{Code} \defcaptionname{ngerman}{\lstlistlistingname }{Codeverzeichnis}  \lstloadlanguages{R}  \lstset{% general command to set parameter(s)    basicstyle=\sffamily\footnotesize, % print whole listing small    keywordstyle=\sffamily\footnotesize\bfseries, % ubold black keywords    identifierstyle=, % nothing happens    commentstyle=\sffamily\footnotesize\slshape, % green comments    stringstyle=\sffamily\footnotesize, % typewriter type for strings    showstringspaces=false, % no special string spaces    numbers=left,    numberstyle=\sffamily\footnotesize,    stepnumber=1,    numbersep=10pt,    showspaces=false,    showtabs=false,    frame=lines,    morecomment=[l]{\%},    float=htbp,    numberbychapter=true  }   \begin{document} \let\cleardoublepage\clearpage   \pagenumbering{roman}  \tableofcontents  \clearpage  \vspace*{75mm} \chapter{Einleitung} \section{Motivation} bla bla bla \section{Ziel}  bla bla \chapter{Stand der Technik zur Mustererkennung} \section{Die Zeitreihen} bla bla \subsection{Beschreibung} bla bla \subsection{Erklärung}  bla bla  \subsection{Vorhersage} bla bla \subsection{Kontrolle} bla bla \section{Feature Extraktion} bla bla \subsection{Autokorrelation} \subsection{Was ist Autokorrelation?} bla bla   \subsection{Autokorrelation und Zeitreihen} bla bla  \subsubsection{Zeitreihe-Diagramm}  bla bla \subsubsection{Lagged Streudiagramm} bla bla  \subsubsection{Autocorrelation-Function (Korrelogramm)} bla bla \subsection{Spektralanalyse} \subsection{Was ist Spektral-Analyse} bla bla \end{document}


While doing other projects I discovered that my receptacles (garage ceiling) are 15 amp rated but are on 20 amp circuit. House is 20+ years old. What does it mean?  20-year old code allowed this? Special case for garage ceiling receptacles? House was not built according to the code? Somebody did the work not according to the code afterwards (previous owner)?  Also - these receptacles are not GFCI protected. Inspector did mention another not protected receptacle (at the time code didn't require it) but didn't mention that these receptacles need to be protected. Does it mean there is something special in this case?


I'm experiencing a weird behavior using bash =~ operator. Basically what I want to do is to extract a version number from a xml file. This works: #!/bin/bash  CONTENT=$(cat some_file.xml) PATTERN='<Version>(.*)</Version>' if [[ $CONTENT =~ $PATTERN ]] then   echo ${BASH_REMATCH[1]}  fi  // prints the version number   But this doesn't: #!/bin/bash  CONTENT=$(cat some_file.xml) if [[ $CONTENT =~ '<Version>(.*)</Version>' ]] then   echo ${BASH_REMATCH[1]}  else   echo "Version not found!" fi  // prints "Version not found!"   Why does it match the regex when putting the pattern in a variable, and doesn't match when I just use the string itself?? By the way, if someone has a better way to extract the version number in such case I'd like to hear also, thanks!


What is the difference between “Hochschule” and “Universität/Technische Universität”, especially for master degrees?

I am really confused by the difference between Hochschule (university of applied sciences) and (Technische) Universität ((technical) university) in Germany, especially with respect to the master’s degree.  What is the main difference and features?  Can a master graduate from Hochschule have a chance to do PhD like a graduate from a university in Europe, US, Canada or Australia?


Proof of Unique Solution for Modular Exponentiation In Cryptography

The question is about the encryption equation in asymmetric encryption.  For $c\equiv m^e\bmod n$, prove that for every unique $m$ there is a unique $c$.  Here $n=pq$ where $p$ and $q$ are primes larger than $m$ and the exponent $e$, is $\geq3$ and coprime with $p-1$ and $q-1$.  Thanks!


Macbook failing to connect to 5GHz networks

I have a MacBook Pro (Retina, 15-inch, Mid 2014) running on MacOS 10.14.3 (18D42) and since some time I have been unable to connect to any 5GHz WiFi networks while 2.4GHz networks from the same routers are ok.  I have tried several things to no avail:   deleting the network in my wifi settings using three separate and different brand routers  resetting SMC and NVRAM deleting settings in /Library/Preferences/SystemConfiguration/ directory made the 5GHz open without passwords Changed SSID names   The Macbook is able to see the network; however, when I try joining the network, and I enter the password I keep getting an error "the wi-fi network requires a WPA2 password".   Interestingly, I get the same error when the authentication method is set to "Open".    I am 100% sure that the password is correct as I've tried several times (also setting up the 5GHz on different routers).  The networks are working (e.g. from my iPhone, Android phones).  Lastly, below are some of the details of the network setup in my Wi-Fi router.


I want to read the manga of naruto because i want to read more anime than just sit down and watch on my computer so can you help me try to find what chapter is episode 150?


Find the $n^{th}$ derivative of $$f(x) = e^x\cdot x^m$$  If i am not wrong i have following  $1^{st}$ Derivative: $e^x\cdot m \cdot x^{m-1} + x^m\cdot e^x$  $2^\text{nd}$ Derivative: $e^x\cdot m \cdot (m-1)\cdot x^{m-2} + 2 \cdot e^x\cdot m \cdot x^{m-1} + x^m\cdot e^x$  $3^\text{rd}$ Derivative: $e^x\cdot m \cdot (m-1) \cdot (m-2)\cdot x^{m-3} + 3 \cdot e^x \cdot m \cdot (m-1) \cdot x^{m-2} + 3 \cdot e^x \cdot m \cdot x^{m-1} + \cdot x^m \cdot e^x$  From here how do I calculate the $n^{th}$ derivative?  Thanks. :)


Why are all of my appliances becoming energized when ground wire is excluded?

I live in Australia, with three-prong 240v power supply including ground prong. I own a simple plug adapter that does not include the ground connection. As far as I'm aware, using any appliance with this plug removes the safety of the ground protection, but should not have any further effects on the appliance. Instead, if I use this adapter with any of my appliances (washing machine, air compressor, etc) the chassis of the appliance becomes energised. By this I mean that I get a strong shock if I touch the chassis. Also, my proximity voltage detector and neon testing screwdriver light up when touching the chassis. My multimeter detects 0.3v running through the chassis (by the suggested method of touching one probe to the chassis and holding the other probe in my hand) Just touching both probes to chassis and trying all settings on multimeter gives infinite "1" result.  What is going on here? How serious is this problem?  Notes: 1. Yes, this is a follow-up to a previous question asked. 2. Yes, I have booked an electrician to come out, but it is always good to investigate yourself so that I can make sure that the electrician addresses the problem correctly. Also, I want to know if it's even safe for me to be in my house and use my appliances in the meantime.


Faces are Missing when Import from Blender to Unity

I am having a very weird issue with Blender. I have created a model of a mansion, with each face on the roof being a flat, solid object. However, when I import the model into Unity, the outer faces of the roof are missing.  I have tried subdividing and triangulating the mesh as other posts have recommended. However, the faces are still not showing in Unity.  Any help would be greatly appreciated.


SQL Server Money gives wrong values when calculated back

It seems Money has a fixed precision and always have 4 decimals. This causes me problems cause lets say I have a table of items to sell, like below  create table #example (    id int,    name varchar(50),    price money )   If the money column in #example is the price before VAT and VAT value is 8%, 4 decimals might not be enough. In below example I'm using an item price of 11usd (before vat)  insert into #example (id, name, price) values (1, 'asd', 11/1.08)   A select from #example now gives:   id  name price 1   asd 10,1852   If I want to use this price to add the vat value I get the wrong value:   10.1852*1,08 = 11,000016   This leaves a wrong margin of 0,000016USD. Obviously I'm using it wrong. Anyone have any input on where I'm wrong on this?   Edit: I wouldn't say the attached question has my answer. I'm already certain to use money and I just need help on calculating the values back.


Is there any group with these conditions?

Is there any infinite group $G$, such that $G^\prime$ is Abelian, and any Abelian and normal subgroup of $G$ is finite? In other words:   $G^\prime$ is Abelian $\forall H \trianglelefteq G$ : ($H$ is Abelian) $\Rightarrow |H| < \infty$


A permanent magnet produces lines of magnet flux that we call a "magnetic field".  Those lines come from inside the magnet, come out of the N pole, loop outside the magnet, & return back into the S pole to complete a magnetic circuit.  Using ferromagnetic materials, other magnets, &/or test equipment, we feel & measure forces that are caused by a magnet/s when other materials are placed within close enough proximity to the magnet/s (i.e. within their magnetic field/s).  We therefore conclude that the magnetic lines flow in a specific direction & exert definite forces (i.e. magnitudes/strength) on some materials (ferromagnetic & other magnets), depending on where those materials are placed within the magnetic field of a magnet/s.    We label those forces as "H Field" & "B Field". We measure H in terms of Amperes/meter. We measure B in terms of Newtons/meter/Ampere (or Tesla). We also commonly defined B in terms of the force that it exerts on moving electric charges (i.e. the Lorentz force).  An "Ampere" is basic unit of electrical current in the SI system, which = 1 Coulomb per second--which is formally defined to be the constant current which if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed one meter apart in vacuum, would produce between these conductors a force equal to 2 × 10 −7 newton per meter of length.  A "Coulomb" is the standard unit of quantity of electricity in the SI system, which = the quantity of charge transferred across a conductor in which there is a constant current of 1 Ampere/Second.  Consequently, those "magnetic lines" are currents (or flows) of charges that don't appear to need any external source of energy to continue generating their currents.  We also know those magnetic lines exist inside a vacuum, so they are independent of air molecules to flow outside of a magnet.  So now my questions:   Exactly what charged particles are flowing outside (and inside) a permanent magnet that create the magnetic "lines"?   Do those particles come from something inside the magnet or does the magnet do something outside of it to affect unknown particles to make the lines? If there is a current (i.e. a continuous flow of charged particles), then why don't we harness that current like a water wheel (instead of 'using energy' to rapidly move copper wires through magnetic fields--like we do with electricity generators?)  Shouldn't we be able to get the line currents to charge a capacitor (or or other device) & then otherwise discharge the capacitor for the energy that we want?


Preventing Sql injection - the right way

I am trying to learn and better understand how to properly prevent sql injection and properly extract database information to show in a website.  I am currently using mqli_real_escape_string but the problem is when I extract the data there is a slash where the user may have entered an apostrophe or a quote, such as O'Connell, etc...  If I use a function to remove slashes, it defeats the purpose of using the mqsli_real_escape_string.  What is the proper way to prevent injection while allowing usage of apostrophes where necessary?   MySql  $name = mysqli_real_escape_string($link, $_POST['commentName']); $comment = mysqli_real_escape_string($link, $_POST['commentMessage']); $BID = mysqli_real_escape_string($link, $_POST['BID']);   HTML/PHP
<?php echo $name ?>

<?php echo $comment ?>


Setuid bit seems to have no effect on bash

I was experimenting a bit and noticed something strange: setting the setuid bit on a copy of bash located at /usr/bin/bash-test seemed to have no effect. When I ran an instance of bash-test, my home directory was not set to /root and when I ran the whoami command from bash-test, my username was not reported as being root, suggesting that bash-test was not running as root. However, if I set the setuid bit on whoami, I was reported as being root in any shell, as expected.  I tried setting the setuid bit on /usr/bin/bash as well and observed the same behavior.  Why is bash not running as root when I set the setuid bit on it? Could selinux have something to do with this?


Since it does not allow nonterminating computation, Coq is necessarily not Turing-complete. What is the class of functions that Coq can compute? (is there an interesting characterization thereof?)


Why can't I catch Uxie or Azelf even though I have the requirments?

I tried to catch Uxie, Azelf and Mesprit, but could only catch Mesprit. I know that they appear at different times, but it is 8:07 pm for me and Uxie does not appear.   My 3DS time is at 20:01 (I'll change it soon) and Uxie still doesn't appear. I decided to leave Nameless Cavern and land there again, but it didn't show up. I have 3 Pokémon with max happiness. Why can't I catch Uxie or Azelf?


Removing options features from Gboard suggestion bar

Is there a way to remove the option items, including the arrow on the left, without removing the suggestion bar completely? I use the suggestions for words, but have no use for accessing things like themes and stickers. I've provided a photo of the offending items, since I'm not sure how to properly describe them. I'm using a Pixel 5.


Is it a big mistake if I say "The thing I love are flowers"?

So I was wondering if both forms are correct      The thing I love is flowers   and   The thing I love are flowers


Do simpler questions seem to attract more upvotes?

I have been noticing over the last month (on Stack Overflow), that simpler (perhaps somewhat duplicate) questions seem to get a lot of attention, as compared to the more challenging long-ish questions.  As a result, the answers tend to receive a greater number of upvotes (simply due to greater views) even though the answer might be a copy of an already existing Q/A. Moderators do take care to mark most of these questions as [duplicate], but many slip through. What could be a possible solution to this?


Parsing regex with Javascript IF THEN ELSE

Adding a Regex101 URL:   I'm been working on this problem for about 3 and a half hours.  I can't for the life of me figure out what I'm doing wrong. I'm so close to making it work perfectly but I don't know how to check for the first occurrence of {/IF}  My REGEX:  {IF\s*([^}]+)}([\s\S]+)(?:{\/ELSE})([\s\S]+){\/IF}  The file being parsed:  {IF !isLoggedIn}     Sign In {ELSE}     Welcome back, {>username}!
     {# students}
{#>last_name}, {#>first_name}
     {/#} {/IF}  {IF isLoggedIn}     Beta Testing... {/IF}   For some reason, the regex captures all the way to the second {/IF} as the body of the ELSE


How to write "!" symbol between double quotes in bash?

I can't figure out how to write ! symbol in bash scripts when putting it in double quotes strings.  For example:  var="hello! my name is $name! bye!"   Something crazy happens:  $ age=20 $ name='boda' $ var="hello! my name is $name! bye!"   When I press enter at last command the command repeats itself (types itself) without the last !:  $ var="hello! my name is $name! bye"   If I press enter again  $ var="hello! my name is $name bye"   If i press enter again it disappears nothing gets output  $    If I try this:  $ echo "hello\! my name is $name\! bye\!"   Then it outputs: hello\! my name is boda\! bye\!  If i use single quotes then my name doesn't get expanded:  $ echo 'hello! my name is $name! bye!'   Outputs are: hello! my name is $name! bye!  I have it working this way:  $ echo "hello"'!'" my name is $name"'!'" bye"'!'   But it's one big mess with " and ' impossible to understand/edit/maintain/update.  Can anyone help?


Is there an API available to query for all in progress bulk api jobs?

I need to programmatically list all the currently in progress bulk api jobs. I don't see any API methods available to do this.  The goal here is to be able to wait till there are no in progress bulk api jobs and then kick off a new one.  This is not a duplicate. I don't really care if I use APEX or the bulk api or what I use, but I need to be able to get a list of all jobs or ideally of all in progress jobs. Once I have the job ID I can get all the info I need. What I don't know how to do is get a list of all bulk api jobs.


I'm trying to sort the output value that's returned by greatest to least.  Here's an example of the array:  array(     'ACTION' => 'getsupportdepartments',     'RESULT' => 'success',     'TOTALRESULTS' => 2,     'DEPARTMENTS' => array(       'DEPARTMENT' => array(         'ID' => 2,         'NAME' => 'Sales',         'AWAITINGREPLY' => 5,         'OPENTICKETS' => 5       ),       'DEPARTMENT1' => array(         'ID' => 1,         'NAME' => 'Support',         'AWAITINGREPLY' => 15,         'OPENTICKETS' => 15   The code I'm using is:  if(!empty($_GET['sort'])) {   $tmpArray = array();   foreach($arr['WHMCSAPI']['DEPARTMENTS'] as $key => $value) {     $tmpArray[$value['AWAITINGREPLY']] = $value;   }   $arr['WHMCSAPI']['DEPARTMENTS'] = $tmpArray;    ($_GET['sort'] == 'desc') ? krsort($arr['WHMCSAPI']['DEPARTMENTS']) : ksort($arr['WHMCSAPI']['DEPARTMENTS']); }       ($_GET['sort'] == 'desc') ? krsort($arr['WHMCSAPI']['DEPARTMENTS']) : ksort($arr['WHMCSAPI']['DEPARTMENTS']);    foreach($arr['WHMCSAPI']['DEPARTMENTS'] as $department) {     echo $department['NAME'].' - '.$department['AWAITINGREPLY'].'<br />';  }   echo $exc;   However the order of the output from AWAITINGREPLY is not sorting.


I've seen a few users mention that certain SE sites like  and  are unique, as they were originally created as Stack Exchange 1.0 sites.  As a fairly recent user, I don't know what Stack Exchange 1.0 was like. The current version of Stack Exchange is the only version I've ever known.   What was Stack Exchange 1.0? What changed between SE 1.0 and 2.0?


Update metadata field of type TaxonomyFieldValueCollection using REST API

While updating metadata of field type TaxonomyFieldValueCollection I am getting following error.     "{"error":{"code":"-1, Microsoft.SharePoint.Client.ClientServiceException","message":{"lang":"en-US","value":"Cannot deserialize data for type Microsoft.SharePoint.Taxonomy.TaxonomyFieldValueCollection."}}}"


In Diablo 3, are Barbarians ever able to Dual wield 2 handed weapons?

I know they can dual wield single handed weapons, are they ever able to dual wield the two handed weapons, as in some other games?


Does every connected component of $\{z : |P(z)|<1 \}$ contain a zero?

Let $P(z)$ be a complex non-constant polynomial. Let $G$ be a connected component of open set $\{z : |p(z)|<1 \}$. How to prove that $G$ contains a zero of $P$?   I have no idea how to even start; maybe I don't know the required theorem? Can anybody help?


accountsd want to use the "login" keychain

I don't know why but I get this pop-up 5-10 times in a day. It is very frustrating that I have to re-enter the password again and again.  I tried cancelling it but appears again.    I followed the steps shared as the answer , but unable to fix this problem.   Can anyone have idea how to fix the problem that this popup did not get appeared repeatedly?


How many times to patch a tube before dumping?

Related:     video asserts that:   A properly patched area of a tube is stronger than intact tube area Never patch a tube more than 3 times   Those are seemingly contradictory.   The video is just and example and motivation for this question. I have often seem people discard tubes with several patches, after they are punctured again.  Is it true that after some number of patches to a tube, it is better to dump the thing? How many?


Windows 7 SP1 Windows Update stuck checking for updates

I installed Windows 7 fresh and installed SP1. Now, when I try to check manually for Windows Updates it just hangs on the Checking for updates screen.    I tried running the tools in , but this did not fix the issue either:  No matter what I do it just hangs on the "Checking for updates..." screen and goes no further.


Any number $n>11$ is a sum of two composite numbers

I have seen the following problem:  Any number $n>11$ can be formed by the sum of two composite numbers  and it says to prove it by contradiction. I have done the following:  Assume that the sum will be formed by non-composite numbers. Because a composite number is one that has at least one divisor that is not one or the same number; I can assume that it could be the sum of two prime numbers (because these are not composite). From this point I can say that adding both numbers which are primes, a and b, will give us necessarily an odd number. So: $a=2p+1$ and $b=2p+1$, adding both I will have:  $a+b=2\cdot 2p + 2 = 2(2p+2)$ which is an even number, leaving any odd number; and giving us a contradiction that our theorem will hold for any n>11.  A similar proof can be done if we suppose that one number is composite and the other not, in this case any even number will be left out.  is this fine?  Thanks


How to prove that $\|x+y\|_p<\|x\|_p+\|y\|_p$?

Let $l_p=\{(x_n)\in\mathbb{R}^\mathbb{N}: \sum_{n=0}^\infty |x_n|^p<\infty\}$ and consider the following norm in $l_p$: $$\|x\|_p=\left(\sum_{n=0}^\infty|x_n|^p\right)^{1/p}$$ for $x=(x_n)_{n\in\mathbb{N}}$. I'm studying this norm, and I have to prove that the inequality $\|x+y\|_p<\|x\|_p+\|y\|_p$ holds for $x\neq \lambda y$, $\lambda>0$.   My attempt: the restriction is needed because if $y=\lambda x$ then the equality $$\|x+y\|_p=\|(1+\lambda)x\|_p=|\|x\|_p+\lambda\|x\|_p=\|x\|_p+\|y\|_p$$ holds ever.   Now I do the particular case $y=-\lambda x$, for $0<\lambda\leq 1$ (and $x\neq 0$) then:  $$\|x+y\|_p=\|x-\lambda x\|_p= \|(1-\lambda)x\|_p=(1-\lambda)\|x\|_p=\|x\|_p-\lambda\|x\|_p<\|x\|_p+\|y\|_p$$  (the ''$<$'' is because $\|x\|_p>0 $)  Now if $\lambda>1$, I found that the inequality holds again with '''<'' just following a similar approach.     But how can I proceed in the general case? Thanks in advance!


Prove that $b_n$ converges if $a_n$ converges and $a_n+b_n$ converges

I’ve been given this assignment and I’m having a really hard time figuring out how to answer it. I’ve tried proving it in the same way as proving that if $a_n$ converges and $b_n$ converges then $a_n+b_n$ converges, but I got stuck halfway through. I’d really appreciate any help. Thanks in advance!


Any way to make QGIS display band names of a stack properly?

I'm working with several layer stacks that have 100+ bands in QGIS. The stacks are ENVI files, all band names are properly stored in the headers. Unfortunately, QGIS will not diplay them when choosing the style or when extracting info by clicking on the map. However, QGIS will show all the names Properties->Metadata.  Isn't there any way to get the band names to show properly?


Attachment is not attached; rather it shows the contents in mail body using uuencode or mail command in mac osx

I use the below command to attach a file.  mailx -s "Report 05/06/07" add@dom.com < /test_output/report.html  uuencode /test_output/report.html /test_output/report.html | mail -s "mailing my c file" add@dom.com   but the attachment is not attached with mail. The attachment content is shown in the mail body.  How i can solve this or is there any other way to send mail automatically with the attachment?


How can I make money with my DSLR and 50mm lens?

I have a entry level full-frame DSLR with a 50mm f/1.8 lens, the end goal is that I want to generate some cash for buying my next lens/equipment.  I have the following problems:   Portfolio: I am a self-taught photographer, I don't have connections in this industry. That means I don't have access to models to create my portfolio. Time: Since I have a full-time job, my time is limited to weekends and evenings. What can I do with only so much time?   Quick background: I already know how to use Lightroom but not much about Photoshop. I used Photoshop a lot for other purposes (web assets processing) but not for creative photo editing.   If there are ways that would work, I can probably spend a maximum of $500 on equipment. I feel that I don't know how to make my next move here.


Syncing apt-get installations between multiple computers

Is there a way to synchronize my installations (and removals) between multiple PCs?  Preferably with dropbox - since I'm already using that to keep my files in sync.  I thought of an alias for the apt-get install and apt-get remove commands that stores the parameters to a file (one for install, one for remove) and another command that reads all the entries in the file and executes the respective command. Is this a realistic approach?


Why do i get flat and crack french macaron tops

I have tried to make chocolate macarons several times now. Each time I get a flat cookie (no feet) with a cracked top. I've tried baking them at 325 as well as 300 F. Each time, around 4-6 minutes in the oven, they begin to crack. I tried doubling the cookie sheets and leaving one empty cookie sheet at the bottom shelf. I also have an oven thermometer, so I know my oven temperature is correct.  I used aged egg whites ( at least 24 hours old) and I let them dry for 30-40 minutes before putting them in the oven.  This is what they look like after baking:    I'm using the recipe from joy of baking ()  Thank you very much


How do you I create a new user account on Ubuntu?


The derivation and formula to calculate Potential Energy seems quite confusing?

Ok, so I am in the 10th grade, and Physics is my life, and so I always try to enquire things. We were studying the chapter of Work and Energy during our Physics lecture, and when our lecturer described the derivation of formula to calculate the Potential Energy (U) = mgh, something struck me.                                        The derivation goes in this way :- Gravitational Potential Energy, is measured in terms of work done in bringing a body from the ground level to a certain height against the forces of gravity, the work done then gets stored in the form of Potential Energy in the body. Therefore, in our textbook it was given,                             Work = Force x Displacement                                     The least force required to lift the body from the ground will be mg i.e. its mass x acceleration due to gravity(this part is bothering me). Therfore the Force will be mg, while the displacement done by the force will be  the height at which it was raised against the forces of gravity that is h. Therefore :-  Total Work Done in lifting the body = mgh (force x displacement)    Therefore, Potential Energy = mgh.  But isnt it true that the least force required to lift the body should be greater than mg. Since the force of gravity acting on that body too will be mg but in opposite directions and these two forces should cancel each other and the net force will be zero, therefore displacement will be zero and the body will remain in equilibrium. I dont know if this is stupid but can anyone pls answer.


1996 Mongoose size 19" Crossway 650 replacement size inner tube

My bicycle has a label saying  size 19"  . What is the tire size for my bicycle  and the what is the  inner tube size?


Justification of existing methods of formal logic

What is it that mathematicians, and more likely perhaps philosophers, give as an explicit justification that any method of formal logic, which is actually used by mathematicians, or even by automatic theorem provers, to prove anything, be it some theorem or some argument, would be effectively the best method to make valid deductions.  As far as I have been able to ascertain, there is no such justification.  Apparently, all logical proofs, formal and informal, seem to rely ultimately on the intuition of at least some human being as to what formulas are logical truths, and more likely on the consensus of the specialists since Aristotle as to what formulas are logical truths, consensus which itself seems to rely ultimately on the intuition each specialist may have as to what formulas are logical truths, such as for example p and q implies p, the Modus Tollens, Aristotle's syllogisms etc.  While closely related to my previous question on the justification of systems of "logical calculus", the focus here is not on the usefulness of the methods used but on the foundation of formal logic as articulated or even theorised from the perspective of each of the various methods used.


What is the color temperature of an iphone 8 flash?

Is it the same as the iphone 6 or is the iphone 8 stronger? Does it still use 2 LEDs?


How to encode and set url as query string to other url in location.href?

I have following url  http://www.example.com/p1/val1/p1/val2  Now I want to pass third parameter as url like '/path/to/file'  http://www.example.com/p1/val1/p1/val2/url/?????  How can I do that with combination of js and php?  After passing above, I would like to get value of url as '/path/to/file'  I am passing above link through js's location.href.  How to do that?  I am getting following error?  Not Found  The requested URL http://www.example.com/p1/val1/p1/val2/url//path/to/file was not found on this server.


Where to get Mavericks (or older) OS X installer apps to set up Virtual Machines?

Apple now allows you to run OS X inside a Virtual Machine as long as the host is running Apple hardware. Because we need to test our web site on various versions of Safari, we picked up a Mac Mini running Yosemite for testing purposes. The idea is to run Mavericks (currently our largest user base) and possible Mountain Lion in a VM on demand, similar to what .  However, I've yet to be able to find a place to download prior installer apps. I've found other StackExchange posts referring to the App Store, but since this is a new Apple ID there are no previous purchases for old versions, and as far as I can tell they are no longer available to "purchase". Likewise, I have not been able to find any OS X Installer apps on the Apple Developer site.  Am I missing something? Is there an easy-ish way to get these apps to install OS X to a VM?  (For VM host, we are currently using Virtualbox, but would be willing to use VMWare or Parallels if needed)


How do I find integers $x,y,z$ such that $x+y=1-z$ and $x^3+y^3=1-z^2$?

This is INMO 2000 Problem 2.  Solve for integers $x,y,z$: \begin{align}x + y &= 1 - z \\ x^3 + y^3 &= 1 - z^2 . \end{align}  My Progress: A bit of calculation and we get $x^2-xy+y^2=1+z $ Also we have $x^2+2xy+y^2=(1-z)^2 \implies 3xy=(1-z)^2-(1+z)=z(z-3) \implies y=\frac{z(z-3)}{3x}$ and $x=\frac{z(z-3)}{3y} $. Note that since $z$,$x$,$y$ is an integer, we must have $3\mid z$. So, let $z=3k$. So we have $y=\frac{3k(3k-3)}{3x}=\frac{k(3k-3)}{x}$ and $x=\frac{z(z-3)}{3y}=\frac{k(3k-3)}{y}$ . Then I am not able to proceed. Hope one can give me some hints and guide me. Thanks in advance.


Prove $\mathbb{Z[i]}/(1+4i) \cong \mathbb{Z_{17}}$

Prove that $\dfrac{\mathbb{Z[i]}}{(1+4i)} \cong \mathbb{Z_{17}}$. My attempt: $\phi:\mathbb{Z} \rightarrow \mathbb{Z_{17}}$ be the natural (onto) ring homomorphism, sending $a \mapsto \bar{a}$. Hence by universal property of polynomial rings there exists a (onto) ring homomorphism $\phi':\mathbb{Z[X]} \rightarrow \mathbb{Z_{17}}$ such that $\phi'(x)=\bar{4}$  and $\phi'(n)=\phi(n)$ for all $n \in \mathbb{Z}$. Clearly, $(1+x^2) \subset \operatorname{Ker}\phi' \implies$ we can obtain a (onto) ring homomorphism $\phi'':\mathbb{Z}[X]/(1+x^2) \rightarrow \mathbb{Z_{17}}$ where $\bar{x} \mapsto \bar{4}$ Since $\mathbb{Z}[X]/(1+x^2) \cong \mathbb{Z[i]}$ with $i \mapsto \bar{x}$, one can conclude there is an onto ring homomorphism $\Phi:\mathbb{Z[i]} \rightarrow \mathbb{Z_{17}}$ where $i \mapsto \bar{4}$. $1+4i \mapsto 0$ one has $(1+4i) \subset \operatorname{Ker}\Phi$. How can I conclude the reverse inclusion?


dpkg: error processing package shim-signed, locked by another process error

I just ran the Software Updater (on Ubuntu 16.04). While installing the new packages (including a new kernel version) I got a Grub Secure Boot alert. After that the Software Updater crashed.  It stuck at post-installation-triggers on shim-signed.  After having killed all processes related to dpkg I tried to configure it again  sudo dpkg --configure -a   which returned the following:  Setting up shim-signed (1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1) ... debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable dpkg: error processing package shim-signed (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: shim-signed   I fear that if I restart I'll have problems with booting. Can I reconfigure shim-signed, or can I revert the update somehow?


My Firefox keeps telling me there are extra secure certificates pulled in, as well as a frame and icons. What is this teststackoverflow.com site for, and will I miss any SE functionality by blocking it?


Let $A$ be an infinite set that includes Real numbers and its not bounded. Let $B$ be a set of Real numbers $x$ s.t. the intersection $A\cap[x,\infty)$ is $empty$ or includes $finite$ number of elements.    prove or disprove the existence of $\inf B$  if $A$ is not bounded.      Actually this is the third part of the question that I didn't solve. I think there is more than one situation in this case. can someone give me a hint ?


Is there a way to install a module through an existing module's update hook?

I am curious whether there is a way to install a module through an existing module's update hook?


How can I use color in a mathematical expression without losing horizontal spacing?    \documentclass{article} \usepackage{xcolor} \definecolor{red}{HTML}{dd0000} \begin{document} \[3+(-5)-2+3\] \[3+(-5){\color{red}-2}+3\] \end{document}


I’m trying to install a software called RevKit on Ubuntu 12.10 and the following instructions1 need to be followed:      RevKit can be downloaded from the www.revkit.org website. Opening a   Bash shell and assuming that the file revkit-1.3.tar.gz is in the   current working directory, first the package needs to be unpacked:  tar xvfz revkit−1.3.tar . gz cd revkit−1.3       Then, you can build the toolkit. The build process is divided into two   scripts. First, the RevKit environment is created using the bootstrap   script. Afterwards, the RevKit algorithms are built using the build   script. This has the benefit of running the second script only if   changes have been made on the algorithms but not on the environment.   The bootstrap script should only be called once at the beginning. More   precisely, first run the bootstrap script:    ./make.py bootstrap         This will download and compile all dependencies automatically. For   that purpose, compiling boost takes some time. If you already have   installed boost using the distribution’s package manager, the option   -DBOOST PATH can be used to specify its path, e.g. -DBOOST PATH=/usr.    Alternatively you can specify the boost include and libs   path separately by using –boost, –boost-include-dir and   –boost-lib-dir as arguments. Please make sure that your version of   boost satisfies the requirements. After bootstrapping the environment,   the build script needs to be executed. To run this script manually   call:  ./make.py build         This will build the whole RevKit suite including the core, algorithms,   examples, and the Python bindings. The Python bindings enable the CLI   to use RevKit like a shell. If the system cannot build the Python   bindings or if they are not needed, they can be deactivated by   calling:  ./make.py build −DBUILD BINDINGS=OFF       instead. Further packages which are not available in the distribution’s package   manager (e.g. CUDD or PUMA) are downloaded and installed automatically   from the bootstrap script. Boost is also required and will be   downloaded and installed by default.       The build script must be called at least once. Afterwards, the sources   only need to be compiled again if local changes have been performed.   Alternatively, the program make can be executed manually by calling:  make         in the build directory. The build script also provides the options of   enabling and disabling the compilation of unstable and example   algorithms by using the parameters -DBUILD UNSTABLE and -DBUILD EXAMPLES.    if this is correct an gui window should open in the following instructions which am not able to see:  4.1. RevKit Graphical User Interface The RevKit Graphical User Interface enables the creation and execution of customized design processes to be executed. Therefore, a GUI is utilized where the respective tasks can easily be put together by means of item blocks connected to a graph. Each item performs an operation and may have ports for the respective input parameters and output results. Input ports can be connected to output ports forming a channel when they support the same data types. In order to start the RevKit Graphical User Interface, the following command has to be invoked from within the root directory of RevKit:     ./tools/gui/gui.py   I was able to do the first 2 instructions, but after that I am unable to follow what has to be done, i.e. the instructions relating to the bootstrap script. Can anyone tell me what exactly needs to be done? basically i need to get to the gui interface which am unable to do  1


How to convert isodate to x unit in pgfgantt

I'm trying to find a solution to my problem : . So I decided to take a look to the package source code and I found this :   \def\@tempa{none}%     \edef\@tempb{\ganttvalueof{today}}%     \ifx\@tempa\@tempb\else%       \draw [/pgfgantt/today rule]         (\ganttvalueof{today} * \ganttvalueof{x unit}, \y@upper pt) --         (\ganttvalueof{today} * \ganttvalueof{x unit}, \y@lower pt);%       \node at (\ganttvalueof{today} * \ganttvalueof{x unit}, \y@lower pt)         [anchor=north] {\ganttvalueof{today label}};%     \fi%   I understood what the code does so I decided to do like that :   \draw [/pgfgantt/today rule]         (\ganttvalueof{2014-05-19} * \ganttvalueof{x unit}, \y@upper pt) --         (\ganttvalueof{2014-05-19} * \ganttvalueof{x unit}, \y@lower pt);%       \node at (\ganttvalueof{2014-05-19} * \ganttvalueof{x unit}, \y@lower pt)         [anchor=north] {Validation date};%   The problem of solution is that \ganttvalueof take a key name not the key value. How to do get the coordinate of date? Someone could show me how to do to make this code work.  Edit  I changed my code :  \draw [/pgfgantt/today rule]         (\pgfcalendardatetojulian{2014-05-19}{} * \ganttvalueof{x unit}, \y@upper pt) --         (\pgfcalendardatetojulian{2014-05-19}{} * \ganttvalueof{x unit}, \y@lower pt);%       \node at (\pgfcalendardatetojulian{2014-05-19}{} * \ganttvalueof{x unit}, \y@lower pt)         [anchor=north] {Validation date};%   It's still not working. What's the second argument of \pgfcalendardatetojulian?  MWE  \documentclass{article} \usepackage[frenchb]{babel}   \usepackage{pgfgantt} \usetikzlibrary{shadows}  \begin{document} \begin{tikzpicture} % optional    \begin{ganttchart}[x unit=1.8mm,                    y unit chart=0.87cm,                    time slot format=isodate,                    vgrid=*{5}{dotted},                  ]                   {2014-04-14}{2014-07-11}        \gantttitlecalendar{month=name} \\          \ganttbar[progress=100]{title1}{2014-04-14}{2014-04-15} \\         \ganttbar[progress=100]{title2}{2014-04-15}{2014-04-17}    \end{ganttchart} \end{tikzpicture} \end{document}   What I want to do is to have a command \verticalline[style=style, label=some label]{date} that will draw a vertical line like the vertical line for today but at a specified date.


Imagine I'm in /Users/beauthi/Documents in Finder. I want to launch commands in my default terminal, which is iterm, in that location. Is there a specific trick in the Finder app to launch iterm and get directly to the directory /Users/beauthi/Documents ? Thank you very much !


How can I get this table centered in the page?

I have a table that I would like to be fully centered. I have tried using \centering but that hasn't worked.  My code is   \begin{table}     \begin{tabular}{|p{5cm}|p{1.4cm}|p{5cm}|p{1cm}|p{3.5cm}|}         \hline          More/Less(IV) of& Leads to & More/Less of (DV) & Due to & Reason\\          \hline          An increase in worldwide internet coverage & results in & an increase of video games with online functionality  & Due to & an increasing number of customers with internet \\          \hline     \end{tabular} \end{table}   It ends up looking like this


Calculating the peak current of my boost converter

I am stuck while calculating the peak current in the boost converter through the inductor.  Can you please check if I am right?  Ipeak=(Max Voltage/ R2) = 18/1000=0.018. So, my peak current through the inductor is just 18mA? Am I doing it correct. If this is correct, how will I account for the Vce drop inside the pin1 and pin2 of the IC. The darlington transistor inside the IC is just like a normal transistor. I have added two transistor outside the IC instead of using the darlington switch in the IC for thermal purposes.   Can you please help me with the calculation of Vswce and Ipeak. The calculation of Vswce is not mentioned in the datasheet. So, please help. And the calculation of Peak current is mentioned in the datasheet. But is my approach of calculating the peak current through the inductor right?


Command sudo not found, even though it is installed

This happened to me after installing java. I believe I messed with the ./bashrc file if I'm correct.  I've checked my files and sudo is still there, but ubuntu seems to not be able to find it.  Before installing java I could use sudo.   Any help is greatly appriciated.


Python NxN matrix is not setting None values correctly

I have the following code in Python 3:  def matrix(n:int) -> list:     matrix = list([[None]*n]*n)      count = 1     for i in range(n):         for j in range(n):             print(i, j, count)             matrix[i][j] = count             count += 1      return matrix  number = 3 print(matrix(number))   Below is the print result:      0 0 1     0 1 2     0 2 3     1 0 4     1 1 5     1 2 6     2 0 7     2 1 8     2 2 9     [[7, 8, 9], [7, 8, 9], [7, 8, 9]]   As you see, indexes are correct, but it does not return the expected value of [[1, 2, 3], [4, 5, 6], [7, 8, 9]]. There has to be a fundamental reason for this behavior, and of course, by using other methods, such as append(), the result is correct.


The following is the definition of integral scheme as mentioned   Let $X$ be a scheme. We say $X$ is integral if it is nonempty and for every nonempty affine open $\operatorname{Spec}(R)=U \subset X$ the ring $R$ is an integral domain.  How do I show that for any open set $U$, $\mathcal{O}_X(U)$ is an integral domain?


Browser where I can add my own custom CSS or Javascript

Is there a way to load my own custom CSS or Javascript while using a browser?  When I'm accessing a website or developing a website I want to load my own custom scripts from my computer. I know this can be done by Firebug or Chrome's developer toolbar, but after you refresh your browser your changes will be cleared too. This is exactly what I'm looking for adding CSS and Javascript, but I wish it has an option where you temporarily save your changes locally. Or it has an option to load external CSS or JS files.   Purpose:   When I'm developing the frontend, sometimes it's convenient for me using Chrome's developer toolbar or Firefox's Firebug to change or tweak CSS properties because I can then see the changes in real time without refreshing. One problem I see is that every time I refresh my browser, my changes also get reset. Now I wish there were an option where I could save my changes locally or load my own external .css file or .js file. I want to customize how some websites look when viewed locally, e.g., accessing a blog that has too many ads. I want to apply CSS properties to hide the junk.   Browsers I use often:   Google Chrome (for development: Built-in Dev Toolbar) Mozilla Firefox (for development: Firebug)


Why use respective interfaces instead of concrete classes?

For example , why should I use     Map<String, List<String>> phoneNumbers = new HashMap<String, List<String>>();   instead of   HashMap<String, List<String>> phoneNumbers = new HashMap<String, List<String>>();


How to create bipolar power supplying from Powerbank 5V 3A

I have 2 ADS1299 analog to digital converters(). I need to give them bipolar mode supplying but I must use a powerbank of 5V 3A. I wonder how can I create a bipolar supply of +2.5v -2.5v as mention in the datasheet from the 5V of the powerbank. I am new in this field. Thank you


NullPointerException while USB Device connection

I try to connect with my custom USB Device. I've done everything step by step with android doc but I still get null pointer at connection object. Here's my activity:  protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);         IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);         registerReceiver(usbReceiver, filter);      usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);     HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();     Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();     while (deviceIterator.hasNext()) {         UsbDevice device = deviceIterator.next();          if (device.getVendorId() == 1659 && device.getProductId() == 8963) {             this.device = device;             usbManager.requestPermission(device, mPermissionIntent);             Toast.makeText(MainActivity.this, "vendor: " + device.getVendorId() + "ID " + device.getProductId() , Toast.LENGTH_SHORT).show();             break;         }     }   And this is how I try to connect with USB device :  mTestButton = (Button) findViewById(R.id.button);         mTestButton.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 usbInterface = device.getInterface(0);                 if (connection != null) {                     connection = usbManager.openDevice(device);                     connection.claimInterface(usbInterface, false);                  for (int i = 0; i < usbInterface.getEndpointCount(); i++) {                     UsbEndpoint end = usbInterface.getEndpoint(i);                     if (end.getDirection() == UsbConstants.USB_DIR_IN) {                         usbEndpointIn = end;                      } else {                         usbEndpointOut = end;                     }                 }                  //SEND START COMMAND TO  THE USB DEVICE;                 int result = connection.bulkTransfer(usbEndpointOut, "START".getBytes(), "START".getBytes().length, 1000);                 Log.e("SEND RESULT", result + "");                   //START READING in run method                 readThread = new Thread((Runnable) MainActivity.this);                 readThread.start();              } else {                 Toast.makeText(MainActivity.this, "Connection is null", Toast.LENGTH_SHORT).show();             }   But connection is still null :/ Help, please.


Does a charged capacitor weigh more than uncharged?

I know that charging a capacitor only moves particles from one plate to the other, so the total amount of charge in the capacitor does not change, nor does the total number of particles. However, the charged capacitor does have electrical energy that the uncharged capacitor does not have, and energy has a mass equivalence according to $e=mc^2$, so wouldn't the capacitor weigh a little bit more when charged? A 470 μF capacitor charged to 3.3 V, for instance, would have a stored energy of , which has a mass equivalence of , which is the weight of ~1,416,666 carbon atoms? Likewise, a superconducting loop inductor would weigh slightly more when it is  (has a current flowing through it) vs unenergized because of the mass equivalence of the energy stored in the magnetic field?


What if my overall ANOVA is significant but my poct hoc independent t-tests aren't?

I have conducted a 2x3 mixed factorial ANOVA, my interaction effect has come out as significant but when I go on to do an independent t-test to determine where the differences are my t-tests all come out as non-significant. My question is how would I interpret this? what does it mean?


Is it possible (and not too difficult) to draw a table in the shape of an arrow? I think it's best explained giving an :    I'd like to draw a table almost exactly like this. However, the 2nd, 3rd and 4th row don't have to be like that but can be just regular cells.  Is it possible to draw this easily or should I just make it in a vector program and import it in my LaTeXfile as a picture?


How to declare an array explicitly in an object?

I'm a student, and I've never tried declaring an array explicitly like this before. I want to put more than one sudoku grid into the class for the finished product, or else I would declare and initialize the array in one statement. I want for "solved" to refer to a different grid depending on whether an easy, medium or hard sudoku grid was selected. Is that possible? The way that I've written it results in a null pointer exception, but I am not sure how to declare an array as a class member and then initialize it explicitly within each constructor. If you could please straighten me out on syntax, I would appreciate it. I guess that something must be wrong with how I am declaring that array. This is what I used to test it: public class SudokuDriver {  public static void main(String[] args) {      SudokuSolution solved = new SudokuSolution();          System.out.println(solved.getSolved(0, 1));     System.out.println(solved.toString());  }}  And here is the class that I am testing: public class SudokuSolution { private int [][] solved;  public SudokuSolution () {          int [][] solved = {                  {6, 9, 7, 8, 3, 1, 4, 2, 5},                 {2, 8, 4, 9, 7, 5, 1, 6, 3},                 {5, 3, 1, 2, 6, 4, 9, 7, 8},                 {3, 4, 9, 1, 5, 6, 2, 8, 7},                 {7, 5, 8, 4, 9, 2, 3, 1, 6},                 {1, 6, 2, 7, 8, 3, 5, 9, 4},                 {4, 2, 6, 3, 1, 7, 8, 5, 9},                 {8, 1, 5, 6, 4, 9, 7, 3, 2},                 {9, 7, 3, 5, 2, 8, 6, 4, 1}             };     }      public int getSolved(int a, int b)  {                  return solved[a][b];                 }          public String toString()  {                  StringBuilder grid= new StringBuilder();         int i, j;                  for (i=0 ; i < solved.length; i++) {             for (j = 0; j < solved.length; j++)  {                 grid.append(solved [i][j] + ((i==solved.length - 1) ? "\n" : " "));             }         }                  return grid.toString();     }  }


Could the world be represented as binary?

The Matrix the movie regards the whole world as being binary and us living in a computer simulation. Could the world be represented as binary similar to a matrix or is that not practical give quantum mechanics?


How to install Hindi Mangal Unicode Font on UBUNTU? I always used this font on Windows OS but don't know how to install Hindi Mangal Unicode Font on UBUNTU?