SSH server accepts key ONLY if user is logged in (on server)

I can connect to my server using (id_rsa) key WHEN the local account on the server is logged in.   If I reboot server and leave it at the login manager,and then attempt to connect,  SSH returns                      Permission denied (publickey)   Permissions to /.ssh and .ssh/authorized keys are 700 and 600 respectively on both server and client.   Client:  henry@MSI-LT17:~ > ls -la ~ | grep ".ssh" drwx------   3 henry henry  4096 Jan 23 16:31 .ssh henry@MSI-LT17:~ > ls -la ~/.ssh | grep "authorized_keys" -rw-------  1 henry henry  228 Jan 23 16:31 authorized_keys   Server:    henry@henry-dt:~ > ls -la ~ | grep ".ssh"                                                                                drwx------  2 henry henry    4096 Jan 19 18:24 .ssh henry@henry-dt:~ > ls -la ~/.ssh | grep "authorized_keys" -rw-------  1 henry henry  397 Jan 19 18:56 authorized_keys   Here is the -vvv output of the attempted login:  debug3: remaining preferred: keyboard-interactive,password debug3: authmethod_is_enabled publickey debug1: Next authentication method: publickey debug1: Trying private key: /home/henry/.ssh/id_rsa debug1: key_parse_private2: missing begin marker debug1: read PEM private key done: type RSA debug3: sign_and_send_pubkey: RSA 0d:a8:df:84:1b:25:6e:7f:04:ad:98:87:bd:0b:7d:88 debug2: we sent a publickey packet, wait for reply debug1: Authentications that can continue: publickey debug1: Trying private key: /home/henry/.ssh/id_dsa debug3: no such identity: /home/henry/.ssh/id_dsa: No such file or directory debug1: Trying private key: /home/henry/.ssh/id_ecdsa debug3: no such identity: /home/henry/.ssh/id_ecdsa: No such file or directory debug1: Trying private key: /home/henry/.ssh/id_ed25519 debug3: no such identity: /home/henry/.ssh/id_ed25519: No such file or directory debug2: we did not send a packet, disable method debug1: No more authentication methods to try. Permission denied (publickey).   I suspect the debug1: key_parse_private2: missing begin marker has something to do with it...


Remove duplicates based on inner value from multidimensional arrays

I have three arrays in PHP. Example structure of arrays is as given below. I want to check if id is present in first then value with that it should not be repeated in any other arrays. fo eg in arrays below record with id 200 is present in first array then it is again in third array so I want to remove  c0 from third array there will be 9 such arrays. What will be dynamic way for it.  Array (     [a0] => Array         (              [id] => 100              [Country] => some country         )      [a1] => Array         (             [id] => 200             [Country] => some country          )  )    Array (     [b0] => Array         (             [id] =>300             [Country] => some country          )      [b1] => Array         (             [id] => 100             [Country] => some country             [city] => some city          )  )    Array (     [c0] => Array         (             [id] =>200             [Country] => some country             [state] => some state          )      [c1] => Array         (             [id] => 400             [Country] => some country          )  )


I want to do an inline check to see if an object exists or is None.  Coming from LUA I'm used to writing print user and 'logged in' or 'not logged in'.  However when searching the web, I can't find this method anywhere. Instead people advice you to use print 'logged in' if user else 'not logged in'.  Both methods work though, is there a reason why I shouldn't use print var and 'yes' or 'no'?


Comparing different open source GIS servers?

I currently know the following open source GIS servers:   : java based, vector and bitmap support, also supports. Is now on par with mapserver (performance-wise). : c/c++, used to be the fastest server. Better for raster than vector? : do not know this : the new kid on the block? do not know much about it, but it looks appealing : as far as i know, only retrieves vector-data for display in openlayers. There does exist a rails implementation.   If possible i would like some kind of comparison, which did you choose or prefer and why?  I am looking at building a rails website, and need some kind of GIS server. I will need raster and vector data (clickable). Is this doable with one server? Backend database will be Postgis.


Knowing Your Limits: What is the maximum length of a question title, post, image and links used?

There's one question in SO I'm planning to answer with a really long answer. While I'm still baking my post, these questions dawned to me:   What is the maximum character length of a post? How many links can I include, at most? How about the number of images? What is the character limit on the question title? Do the limits on questions apply to answers as well, or do they have different ceilings?


What are recommended, general strategies to start block-cipher design and/or analysis?

I (and many others for that matter) have always been fascinated by the inner workings of the modern building block of cryptography: block ciphers.  Now, the ressources on the "black art" of design and analysis of these ciphers are sparse; especially for the entry level. Available information like  seems to be somewhat outdated (due to its age).  What's the general consensus of the “best” (read: recommended) strategy to start designing and/or analyzing modern cryptographical block ciphers?    Nota bene: Think of this as a general, wiki-alike question – for learning purposes only. (Besides that, this Q&A would represent a place we can point people to when alike algorithm design questions arise.)


Are credible intervals confidence regions?

I understand that I'm asking a very pedantic question, but as far as I'm aware a confidence region is a multi-dimensional generalization of a confidence interval and therefore as a credible interval is not a confidence interval, it is not a confidence region, however despite this I'm seen many sources act as if this is not the case. One such example being Hoff's A First Course in Bayesian Statistical Methods, which spends its entire 'confidence regions' chapter talking about credible intervals. Have I missed something? Why are there sources that treat credible intervals as confidence regions despite them not being the same things?


Is there a working online random adventure generator for D&D 3.5e?

I'm looking for a random adventure/encounter generator for D&D 3.5e. It doesn't have to be particularly good or fleshed out, I intend to use it to generate ideas for one-off side- adventures - ideally it will let me spam a few adventure ideas in a short time, until one feeds my inspiration.


I'm able to create a flat diamond will fills, but I'm having some difficulty getting just the outlines. I've tried using borders with inside position, but I end up with thicker strokes in certain areas. When I put them to center, I get these weird pointy corners.


Why does U-235 split into barium and krypton in nuclear reactors?

For my chemistry project I have found the typical fission reaction which occurs in nuclear power plants is when nuclear fuel rods are bombarded with neutrons, splitting U-235 into isotopes barium and krypton and releasing two more neutrons and massive amounts of heat and energy.   My question is why does bombarding U-235 with neutrons split U-235 into barium and krypton?  Are barium and krypton's nuclei the most stable or does the reaction produce the most energy? My question is what makes the reaction so common in nuclear reactors?   Does the reaction give off the most energy out of all other reactions. Also is the reaction man-made or just a natural nuclear reaction?   Can you also tell me if fuel pellets (U02) are the most efficient type of nuclear fuel or are there more efficient types of nuclear fuel?  Similar question but not same question -


how to install Kaspersky internet security 20.4 LTS focal fossa

Please Help ,,,,  I'm download this file from server ,, but how it open and work ... (I'm New in ubuntu )   Kaspersky Internet Security.dmg


What is the purpose of the "new" keyword in Java, PHP, etc.?

In many languages, we use new to instantiate a new instance of a class. For example, in Java:  class MyClass {     int number = 1;      MyClass(int n) {         self.number = n;     } }   MyClass obj1 = new MyClass(5);   However, as I've been using Python more and more, I've come to wonder why the new keyword is even necessary. In Python, we can simply do:  class MyClass:     def __init__(self, n):         self.n = n   obj1 = MyClass(5)   So, what's the purpose of the keyword? Is there some syntactic ambiguity that we resolve by using the keyword?


Cannot get to Ubuntu recovery mode (or Grub menu)

I know there are lots of questions re this, but none solve my exact issue. I accidentally gave a usermod -G instead of -a -G, and so have been removed from sudoers.  I am using BIOS, so most of the threads talking about holding shift to get into recovery mode don't work.  ESC brings me to a grub command line, but cannot get anything useful out of that.  The closest similar question I found (I can't find it again) had the same issue, but his was resolved by typing normal and then it worked.  When I type normal, all I get is that it reboots but then ESC no longer works to even get me into the GRUB menu until the next time I reboot. Ubuntu 20. TIA Edit: Despite this being marked as a dup, it is VERY CLEARLY NOT because I reference all of the normal directions, and explain how it's not working.  Not only that, but I did end up resolving it, and it goes against all of the documentation, thereby making it novel, and likely useful for others.  Typical Stack


Novel about rich industrialist who is recruited by a woman who uses magic, takes him to her world were he crash lands

Looking for a book I read in the 90's (not sure if it was published in the 90's or not).  The story as far as I can remember goes like this. Human-looking aliens evolve on a very hostile planet. They encounter some big bad threat and they cast about for help. They encounter a rich industrialist on Earth and they send a woman to recruit him. She teaches the guy to use magic and how to transform his body. They build a ship and travel to her planet but just before they arrive, she vanishes and he crash lands on this hostile planet.  He goes through many trials and tribulations in order to get to her and eventually he has enough and uses the ability she teaches him on how to transform his body. He transforms himself into a half-man, half-dragon-like creature which allows him to travel to the other side of the planet to get to the girl. On the way he manages to neurally link into a large flying creature that flies very fast, only to discover that it is intelligent and they soon become friends. When he gets to the girl she doesn't recognise him so he gets mad and starts attacking only to realise that it's all been a test set up by these people to allow him to reach higher levels of magic.   There were supposed to be sequels but I never got around to reading them.  I remember the cover art depicted a large dragon like creature with a torso of a man and a woman standing in front of it looking back at him.  Any idea what this book may be?


How does a laptop with HDD function when it's moving?

If a Hard Disk Drive has a head that depends on complete accuracy to read, how can a laptop function if it  is moving?  Is the HDD head strong enough to stay stable and read while the entire laptop is moving?  Is it possible for the head to impact the disk?  If so, what would happen?  Basically, I'm just curious if it's bad to have a laptop running while you move it around  Any answers, insight or corrections are appreciated, thanks!


How to give this permission (-r--rwx-rw-) using CHMOD?

I am studying for a public exam and see   Before answer, I read about chmod and understood that the permission are split in 3 groups (user, group, other), like this:      Nível  u   g   o Permissão rwx r-x ---   Binário 111 101 000     Octal  7   5   0   So, why are there more than 9 (3x3) char in the permission string (-r--rwx-rw-)


What is the point of such handle redirection as 1<&2?

According to what is said :  For example, the following command redirects handle 2 (that is, STDERR) into handle 1 (that is, STDOUT): 1<&2  I understand why we might need to apply the redirection such as 2>&1, but I can't see any reason for applying 1<&2. Could anybody clarify this for me? Thank you in advance.


Comma and Semicolon Use when Listing Items

I am trying to list multiple items, but with a specific area they are located in.      The perfume had top notes of black currant, luscious strawberry,   and sparkling cassis; mid-notes of ginger lily, bright peony,   and pink jasmine; and dry notes of amber wood, white patchouli,   and vanilla musk.   I don't know whether to use semicolons to separate the different areas or colons or even commas. Or, do I use the method used in the example with both?   (Note: Bold is the area location and italic is items in area.)


Python urllib2, basic HTTP authentication, and tr.im

I'm playing around, trying to write some code to use the  APIs to shorten a URL.  After reading , I tried:     TRIM_API_URL = 'http://api.tr.im/api'    auth_handler = urllib2.HTTPBasicAuthHandler()    auth_handler.add_password(realm='tr.im',                              uri=TRIM_API_URL,                              user=USERNAME,                              passwd=PASSWORD)    opener = urllib2.build_opener(auth_handler)    urllib2.install_opener(opener)    response = urllib2.urlopen('%s/trim_simple?url=%s'                               % (TRIM_API_URL, url_to_trim))    url = response.read().strip()   response.code is 200 (I think it should be 202).  url is valid, but the basic HTTP authentication doesn't seem to have worked, because the shortened URL isn't in my list of URLs (at ).  After reading  I also tried:     TRIM_API_URL = 'api.tr.im/api'    password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()    password_mgr.add_password(None, TRIM_API_URL, USERNAME, PASSWORD)    auth_handler = urllib2.HTTPBasicAuthHandler(password_mgr)    opener = urllib2.build_opener(auth_handler)    urllib2.install_opener(opener)    response = urllib2.urlopen('http://%s/trim_simple?url=%s'                               % (TRIM_API_URL, url_to_trim))    url = response.read().strip()   But I get the same results.  (response.code is 200 and url is valid, but not recorded in my account at .)  If I use query string parameters instead of basic HTTP authentication, like this:     TRIM_API_URL = 'http://api.tr.im/api'    response = urllib2.urlopen('%s/trim_simple?url=%s&username=%s&password=%s'                               % (TRIM_API_URL,                                  url_to_trim,                                  USERNAME,                                  PASSWORD))    url = response.read().strip()   ...then not only is url valid but it's recorded in my tr.im account. (Though response.code is still 200.)  There must be something wrong with my code though (and not tr.im's API), because  $ curl -u yacitus:xxxx http://api.tr.im/api/trim_url.json?url=http://www.google.co.uk   ...returns:  {"trimpath":"hfhb","reference":"nH45bftZDWOX0QpVojeDbOvPDnaRaJ","trimmed":"11\/03\/2009","destination":"http:\/\/www.google.co.uk\/","trim_path":"hfhb","domain":"google.co.uk","url":"http:\/\/tr.im\/hfhb","visits":0,"status":{"result":"OK","code":"200","message":"tr.im URL Added."},"date_time":"2009-03-11T10:15:35-04:00"}   ...and the URL does appear in my list of URLs on .  And if I run:  $ curl -u yacitus:xxxx http://api.tr.im/api/trim_url.json?url=http://www.google.co.uk   ...again, I get:  {"trimpath":"hfhb","reference":"nH45bftZDWOX0QpVojeDbOvPDnaRaJ","trimmed":"11\/03\/2009","destination":"http:\/\/www.google.co.uk\/","trim_path":"hfhb","domain":"google.co.uk","url":"http:\/\/tr.im\/hfhb","visits":0,"status":{"result":"OK","code":"201","message":"tr.im URL Already Created [yacitus]."},"date_time":"2009-03-11T10:15:35-04:00"}   Note code is 201, and message is "tr.im URL Already Created [yacitus]."  I must not be doing the basic HTTP authentication correctly (in either attempt).  Can you spot my problem?  Perhaps I should look and see what's being sent over the wire?  I've never done that before.  Are there Python APIs I can use (perhaps in pdb)?  Or is there another tool (preferably for Mac OS X) I can use?


Is there a systematic way of solving $x^2-x=0 \pmod{10000}$?  Obviously, since we are dealing with modulo $10000$, this is much more complicated as it is not a prime number. I should also address that I am not trying to find all the solutions but I wanted if there is an algorithm-like way of seeking some solutions.  I realise that $0$ and $1$ are trivially solutions and any other solutions must have more than $3$ digits. I also thought about the zero-divisors of this ring but there are too many zero-divisors. Are there more slick way of doing this problem?


How to create a box spanning across rows and columns of a table

Starting from this thread . I'm also aware of  I'm just wondering if there is any quick way like this to create a box spanning across rows and columns rather than having to use TikZ  \documentclass{article} \usepackage{xcolor} \def\boxit#1{%   \smash{\color{red}\fboxrule=1pt\relax\fboxsep=2pt\relax%   \llap{\rlap{\fbox{\vphantom{0}\makebox[#1]{}}}~}}\ignorespaces } \begin{document}  \begin{tabular}{| c | c  c  c  c | }        \hline       Location & \multicolumn{4}{c|}{Rounds}\\         \hline         0 &  2 &  23 &  41 &  42\\     \boxit{1.47in} 1 &  3 &  24 &  42 &  43\\     2 &  4 &  25 &  43 &  44\\     3 &  5 &  \boxit{0.77in} 16 &  26 &  34\\     4 &  6 &  17 &  27 &  35\\     \hline    \end{tabular} \end{document}


Removing or Editing the header on each page in LyX

My document is in (AMS article) mode. The title of my paper shows up as a header on each page. The problem is that the title is too long and it overlaps with the page number. I would like to use a different (shorter) header (one header for all the pages except the title page) or erase the header on each page altogether. How would I do either of these?    If the source code or preamble needs to be edited, can you explain how I can go about making the edit in LyX? (I.e., do I use ERT, edit the settings or something else?)  Here's the source code for the title, but I am not sure if it's helpful:   \title{{\small{EST}}}   \maketitle   My preamble is empty.  Edit: How can I make any of the suggested edits in the linked question in LyX?


What is the difference between passing by value and passing by reference?

What's the difference between:  int i = 0; foo(i);  int foo(int i){ ... }   and:  int i = 0; foo(&i);  int foo(int *iPtr){ ... }   I mean, is passing by reference faster and better for memory/performance? Why should I use reference?  Also, my professor said that when we pass by value we are actually passing for reference.. so what's the real difference between them?  I thought that pointers and passing by reference were used to optimize performance and memory..


What are functions with the property $f(f(x)) = x$ called?

Do functions which, when composed with themselves, are equivalent to the identity function (i.e. functions for which $f(f(x)) = x$ in general) have a name and if so, what is it?  Additionally, am I correct in saying that a such function has a splinter of two, or is it perhaps splinter of size 2 or something else entirely? Or could I say that a such function has an orbit of size 2?


how to add custom classes and div to drupal search form.. i want to change complete layout of the block

I want to set following HTML layout in my search form.
 <form>     <input class="sb-search-input" placeholder="Enter your search" type="search" value="" name="search" id="search">     <input class="sb-search-submit" type="submit" value="">     <img src="<?php echo $theme_path;?>/images/search_icon.png" alt=""> </form>     but when i render the form using module invoke i got all classes and divs that are associated with search block,i want the above HTML to be applied to my search block.


Stuff which squares to $-1$ in the quaternions, thinking geometrically.

How can we think of the set$$\{x \in \mathbb{H} : x^2 = -1\}$$geometrically? Is this set finite or infinite? Are there some more geometric ways of thinking about than meets the eye? Here, $\mathbb{H}$ denotes the quaternions.


How to add background-color overlay to a div?

I have two empty div elements inside a div. The two elements are class labeled as "img" and "overlay". On the "img" I attached a background url and the "overlay" I only want to add a background color on top of the background url adding an overlay effect. I tried playing with positions, height and padding but it only misalign the items. The divs are inside another div which has a grid display property. Html Part:

  Css Part: .img{   height: 100%;   width: 100%;   background: url("../img/star.jpg");   background-size: cover;  }  .overlay{   background-color: green;  }


The bevel depth (the radius of the tube) is set to 9cm but it actually isn't when compared to the background grid. This is is confirmed by importing it into sketchup and scaling it to the proper units it turns out the radius is only around 2.286cm. This problem only shows up on certain projects. What's wrong and how do I fix it?  (sorry that I can't upload the file, it's a long story)


How to write a Thesis with font of size 14pt?

I want to write my thesis in latex, with a font of size 14pt. I wrote   \documentclass[14pt,oneside,a4papper]{book}   but the font is not of 14pt. Can someone tell me how can I write with 14pt? Thank you!


Why does light reflected on water tends to 'smear' in the vertical direction?

I have noticed that in city lights reflected on the water are very often smeared more in the vertical direction (relative to the reflecting plane I presume), than in the horizontal direction. See, for example, pictures .  I can't figure out why. I think it would make sense if the waves happened to have their wavefronts perpendicular to the line of sight, but I think this is unlikely, as it appears you can see it from many angles.


Does gravity play a role in the Earth's equatorial bulge?

I'm trying to understand why the Earth bulges at the equator. But before looking at the Earth, which introduces gravity, I wanted to make sure I understood the shape of some rotating objects and if/why they have a bulge.  A metal sphere: A very rigid object. If this is rotated then there is no bulge because it requires a lot of energy to deform the object.  A ball of sand: Nothing is connected. If this rotated then all the sand is simply thrown off due to inertia, leaving nothing behind after a time.  A ball of dirt: Somewhat rigid. The dirt wants to "fly off" due to inertia but tension keeps the object pulled together, as a result there is bulge at the equator - where the velocity is fastest and thus more "tension" (more bulge) is needed.   Does the "ball of dirt" situation accurately resemble Earth? If so, then does this not suffice to explain why the Earth bulges without even needing to mention gravity? Or is Earth more like the "ball of sand" which is can only be kept together (while rotating) under the force of gravity? Or is it something between or neither at all?  I'm afraid I'm terribly confused as to how the various effects come in to play and interact to create an equatorial bulge. Some sources have tried to explain in terms of an  but I'm not entirely satisfied with that as an explanation (actually that source even indicates the equilibrium approach is not so straightforward).


I need to find the area of a parallelogram with vertices $(-1,-1), (4,1), (5,3), (10,5)$.  If I denote $A=(-1,-1)$, $B=(4,1)$, $C=(5,3)$, $D=(10,5)$, then I see that $\overrightarrow{AB}=(5,2)=\overrightarrow{CD}$. Similarly $\overrightarrow{AC}=\overrightarrow{BD}$. So I see that these points indeed form a parallelogram.  It is assignment from linear algebra class. I wasn't sure if I had to like use a matrix or something.


Do I need an Airport Transit Visa? (Copenhagen to Exeter via London and Dublin)

I'm traveling to Exeter from Copenhagen via London (Southend) and Dublin (I have no idea why the airplane is landing in Ireland).  I am a Danish citizen with a Danish Passport and all.  Question is, do I need an Airport Transit Visa?  I am traveling on April 13th (March 29th = Brexit 🙄)  This is how I am traveling to Exeter:  Copenhagen -> London Southend Airport (22.25 - 23.55 local time) Ryanair  London Southend Airport -> Dublin Airport (06.55 - 08.10) Ryanair  Dublin Airport -> Exeter Airport (09.55 - 11.05) flybe  PLEASE don't come @ me if it's obvious that I need an Airport Transit Visa 😂  Last time I was in the UK, I was on my way to Egypt, so I needed a Visa for that.  OBS! In Dublin I'm changing Airlines, so have that in mind!


can't create new folder anywhere in windows 7

I'm not able to create new folders in my laptop. Even when I right click on my mouse it's not showing me the new folder option. Is this any spam or not?   I tried the following registry fix:    but it says that NewFolderFix.reg, didn't work:   Not all data was succesfully written to the registry. Some keys are open by the system or other processes.


AutoCommit Flag of java.sql.Connection not working for SPARQL

I set "AutoCommit" flag for java.sql.Connection object as false when executing SPARQL Query but the flag is ignored. Given below is the part of the code that executes the Query.      Connection conn;     OracleDataSource oracleDataSource;     try {         oracleDataSource = new OracleDataSource();         oracleDataSource.setURL("");         oracleDataSource.setUser("");         oracleDataSource.setPassword("");         conn = oracleDataSource.getConnection();         conn.setAutoCommit(false);     } catch (SQLException e) {         LOGGER.error("Exception occurred in preparing connection: ", e.getMessage());         throw (e);     }      String sparqlInsertQuery = "BEGIN SEM_APIS.UPDATE_MODEL('RDF_MODEL','xxxxxxxx'); END;";      try (Statement stmt = conn.createStatement()) {         stmt.executeUpdate(sparqlInsertQuery);     } catch (SQLException e) {         LOGGER.error("Cannot Execute Query: ", e);         throw (e);     }      //conn.commit();     conn.close();   Eventhough I have added "conn.setAutoCommit(false);", the statement "stmt.executeUpdate(sparqlInsertQuery);" commits the Triples into the Model. Instead of SPARQL Query, if I use SQL Query, the "AutoCommit" flag value is considered and everything works fine.


Discuss the continuity and differentiability of $e^x$?

Discuss the continuity and differentiability of $e^x$ ?    I know its continuous at all points, but how to check for differentiability ?


What is the recommened way to dual-boot Windows 8.1 and Ubuntu on two HD?

I am building a computer and have a 1 TB hard drive and a 250GB SSD. I would like to install both OS on the SSD and have them both be able to access the HD. Would it work to install both on the SSD and just partition the HD in half?   How should I dual-boot Windows 8.1 and Ubuntu on two storage devices?


I read in twitter that: $$\displaystyle\sum_{k\geq 0}^{} \binom{n}{2k} = \sum_{k \geq 0}^{} \binom{n}{2k+1}$$ So far I've noticed that if $n$ is odd then $n=2k+1$ and we have that $$\binom{2k+1}{k-i} = \binom{2k+1}{k+1+i} $$ for $i= 0,1,\dots,k$  Since we must have that one of $k-i$ , $k+1+i$ must be odd and the other even for all $i=0,1,\dots,k$ then we must have that $$\displaystyle\sum_{l\geq 0}^{} \binom{2k+1}{2l} = \sum_{l \geq 0}^{} \binom{2k+1}{2l+1}$$ I don't know what to do when $n$ is even or if there's a way to prove this without breaking it into cases.


Is there any way i can password protect or lock folder in ubuntu that can also be opened in windows 8?? I am using windows 8 and ubuntu 14.04


In Java, how do I convert a byte array to a string of hex digits while keeping leading zeros?

I'm working with some example java code for making md5 hashes. One part converts the results from bytes to a string of hex digits:  byte messageDigest[] = algorithm.digest();      StringBuffer hexString = new StringBuffer(); for (int i=0;i<messageDigest.length;i++) {     hexString.append(Integer.toHexString(0xFF & messageDigest[i]));     }   However, it doesn't quite work since toHexString apparently drops off leading zeros. So, what's the simplest way to go from byte array to hex string that maintains the leading zeros?


independent variables in Random forest model

Is it reasonable to run a random forest model with an independent variables that has almost little or no variations. How they impact the model and whats their role in predicting the dependent?from technical point of view I believe they will not be used in building the tress and will have no role in predicting the DV


Difference between clustered and nonclustered index

I need to add proper index to my tables and need some help.  I'm confused and need to clarify a few points:   Should I use index for non-int columns? Why/why not I've read a lot about clustered and non-clustered index yet I still can't decide when to use one over the other. A good example would help me and a lot of other developers.    I know that I shouldn't use indexes for columns or tables that are often updated. What else should I be careful about and how can I know that it is all good before going to test phase?


I'm using Ubuntu 19.04 and since last Friday I am trying to install GNU Image Manipulation Program. After several attempts, it now shows the error message below (also see the screenshot):     Unable to install "GNU Image Manipulation Program":   snap "gimp" has "install-snap" change in progress     What can I do to overcome this issue?


What's this problem with light in my photos called?

I take photos with my phone (a Galaxy S9) frequently and this problem seems to plague me every time I try taking photos indoors near a window during daytime. The light from the window which is above the table seems to be leaking into the image and it messes with the white balance very badly, along with producing a photo that looks like it was taken with a smudged lens. The first image below is the photo taken on auto mode normally. The second one is similar but I used my finger to cover the top of the lens where the light is leaking in. I put my finger as close as possible to the lens without having it show up in the image. As you can see, the second photo came out much better, without any sunlight leaking in from the top. As a result, the colors are so much better in the second image compared to the first. Is this a problem with my lens, my photography skills, or is it something else?


Difference between 'we both have' and 'we have both'

What would be the difference in meaning between the phrase "We have both noticed a change in your demeanor." and the phrase "We both have noticed a change in your demeanor."?


Ubuntu installation problem (Secure boot)

I want to install Ubuntu 14.04 to a new Acer Aspire E 14 using a bootable pen drive. When I select the ubuntu os iso file from multisystem the PC shows this error:  error:Secure Boot forbids laoding module from  (hd0,msdos1)/boot/grub/x86_64-efi/loopback.mod. error: no server is specified. unaligned pointer 0x6653bd9aeb947c2c Aborted. Press any key to exit._     I have installed Ubuntu in legacy mode and Windows does not appear even in the grub menu. WiFi is not working either.


Is there anything I can do to speed up the time it takes to index my pages? It's currently indexing them on it's own time I believe which is every 2 - 3 days and when working in music and media I need to have the latest post fairly quickly.  My robots.txt file is.  User-agent: * Disallow: /wp-admin/ Disallow: /wp-content/ Disallow: /wp-includes/ sitemap: http://vipes.us/sitemapindex.xml   If I am understanding this correctly, I would put this URL into Google .  But in doing so I still only get some of my pages indexed?


I have got a .ecw-file that I want to somehow import into QGIS 1.8.0.  Is there a plugin that I can install that can help me do this or is there another way?  The .ecw-file contains raster data.


daily up down vote limit reached reviews

Based on the title and browsing "Questions that may already have your answer", this doesn't seem to have been reported yet.  So I've been using the site and voting on questions and answers.  I have even reviewed some items, and in that process, also voted some more, added comments etc.  I go make a coffee, come back, answer a question, vote, and proceed to review some more.  I see First Posts and Late Answers blocked off with the gray comment: Daily up/down vote limit reached; come back in 15 hours.  What gives?  So I cannot flag any more non-answers, add comments, upvote comments, or close questions, delete answers anymore through the review system?


Neural networks: why do we randomize the training set?

I have been told to randomize my training set.  Why is it not a great idea to train a classifier by giving it first all the example of class1, then class2, class3 and so on?


There was a security guard in a bank. In front of him were 100 lockers in rows of 10. He thought of something as he saw all the lockers were closed. He started opening all the lockers whose lock numbers were multiples of 1, then closed all lockers whose number was a multiple of 2,and did the same for 3 and so on. If the locker was open, he closed it, if closed, opened it. He went to open multiples of 1 (all),then 2,4,6,8...and then 3,6,9.. And then finally reached 100.  After all the opening and closing,in the end, how many lockers are open and how many closed?


I use Ubuntu Studio 18.04.2 LTS (64 bit Linux).  I experimented some kind of crash, due to some app which left some too big temporary file, so the home partition was full and the system couldn't start at all.  I erased some personal files, from the documents folder (unfortunately, Ubuntu put that user data folders in that partition and I don't know some way to avoid it when we install Ubuntu) and, then, I recovered some space and the system started normally, again.  But... The question is: Where is/are and What is/are that/those useless temporary files and how to full erase it?  Is there some full automatic command line to do this?  Is there some specific GUI app to do this?


How to search for more than one file at a time using Windows?

I have 1,015 images in a folder and these images is classified into seven categories of medical diagnoses of skin cancer, and the same images are classified in the Excel file by number (the number of each image corresponds to the type of diagnosis of this image). The type of image is labelled as "dx".  Clearly, each image has a specific number corresponding to the diagnostic type, my question is How do I search for a group of files by copying their names from the Excel file and then paste them in the search box in Windows at once. In other words i want to take the names of a hundred images from  the Excel file then search for them by pasting their names in the search box. Can I do that or do I need a particular tool?


I know that the series b. converges as $\sum \frac{1}{n^p}$ converges for $p>1$, So a. also converges. I want to know the sum.          a.$1+\frac{1}{9}+\frac{1}{25}+\frac{1}{49}+.....$          $b.1+\frac{1}{4}+\frac{1}{9}+\frac{1}{16}+.....$


I don't know why the following program is generating this error-> clone has protected access in Object. Can't the derived class access the protected methods of the Object class?  If I skip this statement cloned.id=(String)id.clone(); the program compiles successfully!    class Example implements Cloneable{ String id; void display(){     System.out.println("ID="+id);     } public Example clone() throws CloneNotSupportedException{     Example cloned;     cloned=(Example)super.clone();     cloned.id=(String)id.clone();               //troublemaker     return cloned;     } } class CloneInterface{     public static void main(String args[]){         try         {         Example e1=new Example();         e1.id="a";         Example e2=e1.clone();         e2.id="b";         e1.display();         e2.display();         }         catch(CloneNotSupportedException e)         {         e.printStackTrace();         }     } }


How can latex and pdflatex be both symbolic links to same executable (pdftex) and not behave the same?

When I run  $ latex my_doc.tex   and   $ pdflatex my_doc.tex   it works, and when I run  $ pdftex my_doc.tex   it doesn't work.  The thing is I noticed that both LaTeX and pdflatex commands are symbolic links to the same pdftex executable. That is,  $ which latex pdflatex pdftex   yields  /usr/bin/latex /usr/bin/pdflatex /usr/bin/pdftex   and   $ ls -l /usr/bin/latex /usr/bin/pdflatex /usr/bin/pdftex   yields  /usr/bin/latex -> pdftex /usr/bin/pdflatex -> pdftex /usr/bin/pdftex   So how is it possible that commands being symbolic links to a same executable do not behave in the same way ?  Thanks.  I have Ubuntu 12.10 with TeXLive-full 2012.20120611-4 installed.


Why Lie algebras of type $B_2$ and $C_2$ are isomorphic?

both of Lie algebras of type $B_2$ and $C_2$ have dimension 10 and we can find two basis of them on page 3 in the book: . How could we show that these two Lie algebras are isomorphic by constructing an explicit correspondence between two basis of them. Thank you very much.


How do PCA/SVD Decorrelate the variables

I understood the "technique" for doing SVD and PCA.  However, I couldn't understand these two claims:   PCA/SVD decorrelate the variables They do so using orthogonal transformations   For 1, PCA does the eigen decomposition of covariance matrix and SVD operates on the data matrix. How to explain that they decorrelate the variables?  In 2, I think I am missing some matrix transformation properties. How to see the transformations involved in the techniques of PCA/SVD and why are they only orthogonal.  Many thanks.


Are Java function parameters always passed-by-value?

Just a quick question about how parameters are passed in Java...   ...             if ((index = stdout.indexOf(pattern)) != -1) {                 tidy(stdout, index + pattern.length());                 return true;             } else if ((index = stderr.indexOf(pattern)) != -1) {                 tidy(stderr, index + pattern.length());                 return true; ...      private void tidy(StringBuffer buffer, int i) {         logger.info("Truncating buffer: " + buffer);         buffer = new StringBuffer(buffer.substring(i));         logger.info("Buffer now: " + buffer);     }   In this case, will stdout and stderr (used as parameters in tidy()) have their values changed to new StringBuffer(buffer.substring(i))? My assumption is that they will as object variables(object pointers) are always passed-by-value?


X company offers the best coverage plans. They also offer great benefits. X company offers the best coverage plans. It also offers great benefits. Or X is a known company in the world of tech. They make the best products. X is a known company in the world of tech. It makes the best products. Is using they to refer to a company a grammatically sound choice?


I recently bought a new computer, an HP, but something weird is happening. Every time I install some software that has a “Company” field, it automatically fills it with “Hewlett-Packard”. While the computer is HP, that doesn't mean I work for HP. Is there a way I can change this to a company I really work for?


How do you effectively model inheritance in a database?

What are the best practices for modeling inheritance in databases?  What are the trade-offs (e.g. queriability)?  (I'm most interested in SQL Server and .NET, but I also want to understand how other platforms address this issue.)


I would like to externalize plots that have citations (and or acronyms) in the legend. A simple example below  \documentclass{article} \usepackage[english]{babel}  \usepackage{acronym} \acrodef{ls}        [LS]            {Least Squares} \usepackage{pgfplots} \usetikzlibrary{external} \tikzexternalize \begin{document} \begin{tikzpicture} \begin{axis}     \addplot coordinates { (0,0) (1,0) };     \addplot coordinates { (0,1) (1,1) };     \addplot coordinates { (0,2) (1,2) };     \legend {\ac{ls} \cite{ref1}, \cite{ref2}, \tikzexternaldisable \ac{ls} \cite{ref3}\tikzexternalenable}      \end{axis} \end{tikzpicture}   \ac{ls}  \cite{ref1} \cite{ref2} \cite{ref3}  \begin{thebibliography}{1}   \bibitem{ref1} A.~Xxxxx, X.~Xxxx, ``ref 1,''.  \bibitem{ref2} B.~Xxxxx, X.~Xxxx, ``ref 2,''.  \bibitem{ref3} C.~Xxxxx, X.~Xxxx, ``ref 3,''.  \end{thebibliography} \end{document}   The references are not working with the figure but works in the normal text. I tried using \tikzexternaldisable and \tikzexternalenable as suggested in  but no success. Also I tied with  but could not make it work for my case!  I will appreciate simple and complete solution since I am not an expert with LaTeX.


I would like to plot several discrete signals with pgfplots. So far, I've done the following     \documentclass[border={10pt}]{standalone} \usepackage{tikz,pgfplots,filecontents,amsmath} \pgfplotsset{compat=1.5}  \begin{filecontents}{data.dat}  n   xn  -5   0.0 -4   0.0 -3   3.0  -2   2.0   -1   1.0    0   0.0    1   1.0    2   2.0    3   3.0    4   0.0   5   0.0 \end{filecontents}   \begin{document}  \begin{tikzpicture} \begin{axis} [%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     axis x line=middle,     axis y line=middle,     every axis x label={at={(current axis.right of origin)},anchor=north west},     every axis y label={at={(current axis.above origin)},anchor= north west},     every axis plot post/.style={mark options={fill=black}},     xlabel={$n$},     ylabel={$\boldsymbol{x[n]}$},     xtick={-7, -6,-5,-4,-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8},     ymin=0,     ymax=5.5, ]%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \addplot+[ycomb,black,thick] table [x={n}, y={xn}] {data.dat}; \end{axis} \end{tikzpicture}  \end{document}   The first question is that changing xtick doesn't seem to affect the appearance of the axis, how to expand the xtick? The second question is some signals may have negative values, therefore, the lines will overlap the ticks. My question is is there a way to place the xtick above the axis?


Ubuntu 20.04 & KILLER Wi-Fi 6 AX1650 + BLUETOOTH 5.1

did anybody run this card KILLER Wi-Fi 6 AX1650 + BLUETOOTH 5.1 on Ubuntu ? I have Dell M4800 and want to upgrade my WIFI and BT.


I want to have 2 DNS pointing to single IP on different ports. Please let me known if it possible. DNS 1 - abc.mydomain.com DNS 2 - xyz.mydomain.com What could be possible solution here. Can nginx help me on this. Our DNS provider is godaddy


How this overlay color effect was created?

I'm struggling with a little problem. I want to recreate some kind of overlay effect, but I cannot get close to it. I hope some pros among you know how this overlay was created... Note: I have tried all the blending modes of Photoshop but none of them could give me what I wanted. The closest blending mode seems to be the multiply but it actually removes the orange color from the tiles, which I don't want. Here are the images, if you want to try to recreate the effect on your own:    If you are not able to replicate this effect with Photoshop or something else, do you maybe know, what kind of blending/filter or whatever could have been used to recreate this effect? I have also tried with a temperature shift, since it looks like the blue is added to all the colors without destroying too much of the original color (we can still guess that the tiles were orange), but It doesn't seems to be the way to go either Note: I've showed a simpler problem since the second picture contains only one color. I'd like to be able to use any kind of overlay image


How do you ensure your workers live near their jobs?

I've been playing off and on for a bit. I fully understand the "re-assign all" concept, and have used it many times before. Maybe I didn't really scrutinize hard enough in the past, but this time I tried using the pathing tool to see where my workers were taking up residence after reassigning. For some reason I have workers either choosing locations WAY out of the way (I had a few fishers/foresters choosing to live in areas that made no sense), or apparently choosing a "close by" job, only to link to a location far away (Such as fishers next to fishery A working at fishery B which is really far away, and the ones next to fishery B working at fishery A, again, being really far away).  I've toggled jobs and done as much as I know to try and remedy this, but I keep having this problem. I'm really discouraged from playing because of this, as I already felt that the "manual reassignment" was a ridiculous waste of time micromanaging. Now I see that it doesn't even work properly.  To note, I've made sure that I've had at least 1 house for every 2 workers I intend to have at a job. I've accounted for the fact that sometimes a house is inhabited by 1 person. In my situation, laborers MUCH closer to the target profession are being overlooked when the jobs are assigned.   One thing I've considered is that maybe assigned citizens are taken from their ACTUAL proximity to the job site, instead of their home? It seems pretty likely that the professions are consolidated, instead of each building having individual staffing logic, considering the nonsensical mix-up of my fisheries.  Has anyone else had a problem with this? Is this game even being updated anymore? It's a great game, with such a seemingly minor flaw in AI, or at least a lack of ensuring that bad AI can be effectively micromanaged. It would be a shame if this is as good as it gets.


Proof of Vandermonde Matrix Inverse Formula

I'm working through Exercise 40 from section 1.2.3 of Knuth's The Art of Computer Programming volume 1, but am finding myself unable to produce a rigorous proof, and the one  is suspect and not quite clear enough (for me, at least) in some of the steps; in particular, how to "[identify] the $k$th order coefficient in [the] two polynomials."  The problem is this: given a Vandermonde matrix $[x_j^i]_n$, show that the inverse is given by  $$ [b_{ij}]_n = \left[ \frac{    \sum_{\substack{1 \leq k_1 < \dotsc < k_{n-j} \leq n\\k_1,\dotsc,k_{n-j} \neq i}} (-1)^{j-1} x_{k_1} \dotsc x_{k_{n-j}} }{    x_i \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_i) } \right]_n\text{.} $$  The author gives a hint by stating that the sum in the above numerator is just the coefficient of $x^{j-1}$ in the polynomial $(x_1-x)\dotsc(x_n-x)/(x_i-x)$; and he gives an intermediate result showing the explicit multiplication of the matrix and its inverse as  $$    \sum_{1 \leq t \leq n}b_{it}x_j^t    =    \frac{       x_j \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_j)    }{       x_i \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_i)    }    =    \delta_{ij}\text{.} $$  The only other hint as to the type of solution he was expecting is a reference to A. de Moivre's The Doctrine of Chances, 2nd edition, pp. 197-199, which deals with polynomial recurrence relations and difference products (available ).  At the least, I was just hoping someone could either verify the proof is correct at proofwiki and possibly fill in exactly how one identifies the $k$th order coefficient in the proof; or perhaps explain a proof strategy as to what steps to take where the intermediate result is obtained at some point before the final result.  Thanks so much for any help.


Inline JavaScript for dynamic iframe height in a single line of iframe code

I want to provide my customers with a plugin which they can include in their website. Problem is that the content of the iframe changes everyday and has different heights. As I know the height of an iframe can be specified with css or a simple height tag, but then the height is fixed. I want to make the height change dynamically with the content, and this can be done with JavaScript, but how can I include a working JavaScript line inline the iframe code, so I don't confuse my customers?  Like  <iframe src="..." border="..." onload="..."></iframe>   EDIT I want to provide a single line of code, so that this code can be easily be implemented into the websites from my user.


Is it possible to determine Collection Date of ESRI World Imagery Basemap

It seems like it was possible to do this with Google Imagery if I recall but is there any way to determine the date of collection of Esri's World Imagery basemap (or other basemaps) at a given location?   Something I read indicated that this was updated Sept, 2014 but I don't think that has anything to do with the date of collection.     I have been telling people that it is 2014 Imagery but I've been challenged on that statement because features on the landscape are showing up that have reportedly been removed.     The basemap I'm most interested in knowing about is .


PS4 controller shows up wired, but not on bluetooth for Windows 10

Okay here's the dilemma: Steam's controller mapping recognizes my DualShock 4 controller when plugged in, DS4Windows recognizes my DualShock 4 controller when plugged in, and when I go to pair the device using Bluetooth the device is recognized... as "unknown" but it pairs as a wireless controller.  When the device is plugged into the PC I can see it in devices & printers, and even see it in the "test" area that pops up when you enter into "game controller settings". When I'm in that same game controller settings via wired, under advanced settings it displays: preferred device, wireless controller.  but then something funny happens via bluetooth. Even with little notifications popping up asking me to pair, even seeing its a wireless controller, it doesn't show up in Steam nor in DS4 Windows. It doesn't give me the option to put in "0000" as the code to sync. And the wireless controller shows up in devices & printers, but going inside of that area doesn't display anything. It's somehow being recognized as a wireless controller, but it's just not working at all as a wireless device.


Having returned to the UK from Italy I use the remainder of my C type multi entry Stati Schengen to visit Greece

As the title states can I use my remaining visa now to travel elsewhere within the Schengen zone after recently returning from my original holiday in Italy.  I'm an Indian national with ILR in the UK married to a British national. Previously travelled to Italy without any visa (on the assumption that as accompanied by my spouse, a visa wouldn't be necessary - however decided not to risk it this time as was frowned upon by German airline.)


When I going through java tutorials I got an idea about the pointers are not used in java. but java internally uses pointers, but when we look through developer perspective java supports references only. Then why java does not support pass by reference?


Problem with defining shortcuts for TikZ matrices

For  I wanted to define a shortcut for creating a matrix inside a tikzpicture. As a minimal example, consider  \newcommand\mymatrix[1]{     \begin{tikzpicture}         \matrix[matrix of math nodes] {#1};     \end{tikzpicture}% }   which would then be used as  \mymatrix{     a & b \\     e & f \\ }   But LaTeX complains about Package pgfbasematrix Error: Single ampersand used with wrong catcode at the line with the closing brace of \amatrix{}. Why does it do that and how can I avoid it?


If a subring of a ring R has identity, does R also have the identity?

I know it does not make sense that if a subring of a ring $R$ is commutative, then $R$ is also commutative. (For example, the set consisting of the matrices whose all entries except (1,1)-entry are zero, is a subring of ring of 2x2 real matrices.)  I also considered the case of a ring containing a subring with identity, but I had no ideas. Maybe it seems that it does not make sense, either.  Who give me some examples supporting my guess?


In Minecraft, I'm making an adventure map and doing a dungeon style thing. After you die in the "dungeon", I want all mobs in that specific area to die so the player can try again.   I've tried doing a testfor command but nothing seems to work.


The rotation along z axis is not changing to zero?

Code:  function Start(){    Cursor.lockState=CursorLockMode.Locked;  }  function OnGUI () {    transform.Rotate(0,Input.GetAxis("Mouse X"),0);   transform.Rotate(Input.GetAxis("Mouse Y"),0,0);   transform.rotation.z=0;  }   But the rotation along z axis is not changing to zero.


Say, for example, that there's one process that's writing to a file. While the process is running, I opened the file in notepad. The process keeps  writing to the file.   Other than closing and reopening the file, is there any way for me to "refresh" the data that notepad is showing?


how to protect the db username and password in tomcat server.xml

i have a spring application and i am deploying it on tomcat7. for connection i configured jndi in server.xml here is my xml file.  <Resource auth="Container" driverClassName="oracle.jdbc.OracleDriver"             factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"              global="jdbc/MCDataSource"             initialSize="20" maxAge="7200000" maxIdle="20" maxTotal="75"             maxWaitMillis="15000" name="jdbc/MCDataSource" password="AppDB"             testOnBorrow="true" type="javax.sql.DataSource"             url="jdbc:oracle:thin:@172.19.8.159:1521/OIM.itba.gov.in" username="AppDB"             validationQuery="select 1" />   here i need some suggestions that how can i protect my username,password in production environment . i have seen so many suggestion that we can do encryption but some suggestions are like encryption is not the best way to protect because it can be decrypt it easily.one this i know that i should not pass the plan text like this here. so i just want to know what is the best approach to solve this problem.


It's correct to say that $\log _{ 1 }{ 1 } =1\quad $ & $0$?


Why did the lords and ladies easily believe that Bran has powers?

When Bran got his Three Eyed Raven Powers, it is reasonable to see Bran's company (Meera, Hodor, etc.) believe that he has these visions because they can actually see even the Children of the Forest.  But how did Tyrion and many others easily believe to what Bran says? Personally, I think it should take time to believe how someone with visions can see the past and present. Especially that Tyrion didn't even believe there were White Walkers until he saw one.


If n is such that every element $(\mathbb{Z}/n\mathbb{Z})^{\times}$ is a root of $x^2-1$. Prove that $n$ divides 24.

I have a hard time formulating proofs.  For this problem, I  can see that if $n$ is equal to $8,$ this statement is true.  $(\mathbb{Z}/8\mathbb{Z})^{\times}$ includes elements:  $1,3,5,7$, and all of these are roots of $1-x^2 \pmod 8.$  And obviously $8$ divides $24.$  But how do I prove this without depending on number calculations and only using theorems?  Help Please?  I need a step by step walk through of how to do this proof and what theorems would be appropriate to use.


What is this glass bulb with two parallel electrodes on my PCB?

Might be super obvious, but I've not encountered one of whatever this little dude is before:    I figured some sort of vacuum tube, but no idea beyond that. The two poles aren't linked. Found inside a heating control panel. Help would be greatly appreciated!


how to pass environment variables into dtach?

any ideas how to get environment variables into dtach?  they don't seem to be inherited by default...  FOO=bar && dtach -c /tmp/a-socket env # env does not include $FOO   [edit]  because of Reasons (TM) I need to have some sort of command separator in there.  Either a ; or a &&.    (I appreciate now that this is not a dtach-specific question, it just reflects my poor understanding of shell...)


Do something if Array element starts with a certain letter

(Or does not start with certain letter) Consider the array:  myArray = ['M1','M2','A1']   And:  if ( myArray[1] !== *START WITH M* ) { // something };   Is there a selector which I can use?  Thanks in advance.


How do I remove the annoying Authenticator(Terminal)?

I finally managed to reach to Ubuntu after many unfair-unsolved errors and boot errors as well..  Now another unfair issue detected. I made an user account with password, great, I downloaded steam, I double click it, authenicator shows up but when I type something, it doesnt show on authenticator!!!  It wants a password for the user name account I use to let steam download packages, but when I type anything, it does not show on authenticator!It does do nothing but to say error that I typed nothing. I even deleted password of my username account and it still shows up. What the h!!! is this problem? Its even annoying than Justin Bieber!!  Authenticator is my next nightmare...How do I solve it?


Determining nilpotency of upper triangular matrices

Let $L = n(n, F)$, the Lie algebra of strictly upper triangular $n \times n$ matrices over a field $F$. Show that $L_k$ has a basis consisting of all the matrix units $e_{ij}$ with $j −i > k$. Hence show that $L$ is nilpotent. What is the smallest m such that Lm = 0?  I understand that nilpotent means that when applying the bracket operator repeatedly the contents of the matrix $\rightarrow 0$ after some number of applications, but I'm a little unsure of how to approach this proof. Any help would be appreciated since I'm still very new to Lie algebras.


Complex CSS selector for parent of active child

Is there a way to select a parent element based on the class of a child element in the class?  The example that is relevant to me relating to HTML output by a nice menu plugin for .  The output renders like this:

           Active Page

             Some Other Page

     My question is whether or not it is possible to apply a style to the list item that contains the anchor with the active class on it.  Obviously, I'd prefer that the list item be marked as active, but I don't have control of the code that gets produced.  I could perform this sort of thing using javascript (JQuery springs to mind), but I was wondering if there is a way to do this using CSS selectors.  Just to be clear, I want to apply a style to the list item, not the anchor.


improper integral of exponential function

I have a problem calculating improper integrals, this one for example, can you please help me solve it? $$\int_0^\infty t^3(e^{-t^2})dt$$ thanks in advance.


I have written the below code for sending SMS messages.  SmsManager smsManager = SmsManager.getDefault(); smsManager.sendTextMessage(destAddr, null, mMessageText, il, null);   But this is not updating in my Inbox, I need to save the same message in Inbox, Or is there any way to invoke a native SMS application to send SMS ?


I've been looking at the creation of PDF-forms - ie. PDF-documents with boxes where the user may fill in information like name and phonenumber or simply check a box to confirm something - in LibreOffice.  Is it possible to make such "fill-in-able" PDF-documents with TeX or LaTeX?  If it's possible, which extra (unusual?) packages will I need?    I'm thinking of rather simple forms... perhaps with textbox or textline to fill-in things like name or address, and perhaps check-and/or radio-boxes for confirming or choose between multipple-choice options.  Bonus question...  Is it possible to design such forms with LyX?


I am not a student of mathematics, and I have never studied number theory. I was looking at RSA recently. Euler Theorem is used here. I don't quiet understand $1(mod\quad n)$ in Euler Theorem$a^{\phi (n)}≡1\pmod n$.  Are $1\pmod n$ and $1\; mod\; n$ the same ?   Isn't $1\; mod\; n$ always one? Why is the $ed=1\pmod n$ equal to $d=e^{-1}\;mod\;\phi(n)$?


How to find a file whose size is less than 10 MB?

I need to find a file in my current directory whose size should be less than or equal to 10 MB.  ls -lh gives me the file size of each file but not sure how to find the files whose size are less than or equal to 10 MB.  host@407d:t1_snapshot$ ls -lth   Is there any way I can do that?


Prove that any two consecutive terms of the Fibonacci sequence are relatively prime.   My attempt:    We have $f_1 = 1, f_2 = 1, f_3 = 2, \dots$, so obviously $\gcd(f_1, f_2) = 1$. Suppose that $\gcd(f_n, f_{n+1}) = 1$; we will show that $\gcd(f_{n+1}, f_{n+2}) = 1$. Consider $\gcd(f_{n+1}, f_{n+2}) = \gcd(f_{n+1}, f_{n+1} + f_n)$ because $f_{n+2} = f_{n+1} + f_n.$ Then $\gcd(f_{n+1}, f_{n+1} + f_n) = \gcd(f_{n+1}, f_{n}) = 1$ (gcd property).  Hence, $\gcd(f_n, f_{n+1}) = 1$ for all $n > 0$.  Am I on the right track? Any feedback would be greatly appreciated.  Thanks,


Object, mesh, material, material slot, face, material assignment: How do they work all together?

I've had a hard time to figure out why I couldn't set a different material for a given face on a mesh used by two objects (duplicate by AltD).  As soon as I was assigning a material to a face on one object, the face was also changed on the other object, in spite the material was 'object-linked'.      I initially set the material slots exactly the same for the two objects, including materials used by both objects. What I realized (and the  doesn't help) is that one doesn't assign a material to a face, one rather assign the material slot. This slight difference has indeed a lot of consequences.  The solution was to set different materials to the same slot in each object and not changing the material-face assignment.    Slots have a taste of  for the mass... whatever, this leaves me with more questions:   Is that correct the slots are the actual entities which have the 'storage location' attribute and are stored either at mesh ('data') level or at 'object' level? Is that correct slots (not materials) are assigned to faces, and in the case of object duplicates sharing the same mesh, the face-slot assignment done with the 'Assign' button is shared between duplicates? Is it true that a face is assigned by reference to the absolute position of a slot in the list? The evidence is using the up/down arrow of the slot list in the Material tab, to change the order materials appear, actually changes which material is assigned to a face .   That's the general idea, do I miss an important point regarding the use of the material slots? Any reference to good documentation to go further appreciated, especially a description of the model.


Number of solutions to $x^2\equiv a\pmod m$

Let $a\in \mathbb{Z}/p\mathbb{Z}$ and $m$ is an odd number. Then show that the number of solutions to $x^2\equiv a\pmod m$ is $$\prod\limits_{p|m}\left(1+\left({\tfrac {a}{p}}\right)\right)$$  N.B I know I have to use CRT but how to get the expression?


HELP! I tried to render some objects, but the result is only black!

I want to render 2 object, in the rendered preview it looks fine   butwhen I press F12 the result is only a black screen like this   I have switched the little camera icon in the left on, btw I deliberately switch off camera in object 'Plane' that I don't want to render,   If you want to help me please download this blender file, thanks


First, why the vector bundle, structured from principal bundle, has structure group $G$ ? Second, how to prove the principal $G$-bundle, structured from vector bundle, is principal bundle according the Definition 2.3.3 ? Picture below is from the 65 of Jost's Riemannian Geometry and Geometric Analysis. In fact ,I think the definition 2.3.3 is not a good definition.


I created pendrive bootable through Startup Disk Creator. Now m trying to remove os from pendrive and trying to delete all data from pendrive but its not working. Even after formating, pendrive showing data.


How does someone get to cast more than 40 votes in a day?

And by someone, I mean that evil feline WesleyDavid:        That screenshot was taken just before 4pm PST, i.e. just before 0000 UTC.  That shows KittehHead's votes for the month, which is the same as for the day since it's March 1st.  Just to be sure it wasn't that SE had the time wrong, I tried upvoting something and got the expected "Daily Vote Limit Reached, Please Vote Again in 6 minutes."  So how did Kitteh^H^H^H^H^H^HWesley get 42 votes in one day?  ADDED: It's getting worse... Now it's March 2nd, and Wesley/Cat has 3 extra votes:        Now I finally got an extra vote (take that evil kitteh!), but it hasn't helped me understand why:


How to split command params with quotes?

I have to chunk a command string into params array:  String mystr="myexe.exe param1 param2 param3";   I expect this result:  String[] params={"myexe.exe","param1","param2","param3"};   So far so good, I can simply use a string split by space char " ".  How to do it if params has space chars? How to manage double quoted params?  String mystr="myexe.exe param1 \"param2 with spaces\" param3";   I expect this result:  String[] params={"myexe.exe","param1","param2 with spaces","param3"};


shell for loop with find with filenames containing spaces

Consider a directory with typical Microsoft Windows filenames:   New Document.txt Foo.doc Foo - Copy.doc   I'd like to do something on each file such as:   for sendfile in $(find ${POLLDIR} -type f -mmin +1 -print0) do   echo \"${sendfile}\"   ls -l "${sendfile}"   and-so-on   if success_above   then     mv "${sendfile}" "${donedir}/."   fi done   Please note that I don't want to just run 1 command with "${sendfile}" as the argument. I need the loop to do error checking and other things (like moving "${sendfile}" on success and logging on failure).  What is a "correct" construct to escape/quote the filenames from find so I can use them in a for look like in the ls command above? If possible, I'd like to avoid storing the filenames in a temp file one by one.  I don't think that find -printf '"%p"\n' as suggested by triplee in the comments to question [  ] would work in a for foo in $(...) do construct.  I think replacing "illegal" chars with ? would work for me in this case, but it would be very ugly. The for loop ultimately processes files in ${POLLDIR} and then moves them when done, so the chance of "Foo bar.txt" colliding with "Foo-bar.txt" is 0 (-ish).  My best attempt so far is:   for sendfile in $(find ${POLLDIR} -type f -mmin +1 -print | tr ' ' '?') do   ... done   Any cleaner suggestions?


cmyk to ral needed help asap for paint choose

I need to switch those colors for paint code - ral  BLUE（C:80  M:70 Y:50 K:20）  GREEN（C:50  M:0 Y:100 K:0）  can anybody help ?


I'm writing a Web application that needs to store JSON data in a small, fixed-size server-side cache via AJAX (think: ). I do not have control over the server.  I need to reduce the size of the stored data to stay within a server-side quota, and was hoping to be able to gzip the stringified JSON in the browser before sending it up to the server.  However, I cannot find much in the way of JavaScript implementations of Gzip. Any suggestions for how I can compress the data on the client side before sending it up?


What is the equivalent of 127.255.255.255 for OS/X machines so I can test broadcast udp packets without a network?

I am trying to test my program that makes use of broadcast UDP (not multicast!). In Linux, I can use the 127.255.255.255:64651 address and everything works beautifully, in other words, I send a packet to 127.255.255.255:64651 and multiple clients listening on that port get the packet. A real broadcast example!  Unfortunately on my OS/X machine (Mountain Lion) the same example does not work.  Is there any way I can get 127.255.255.255 to work on mac machines? Any other solution to get broadcast working on my mac machine without a network?  Note: It has to be broadcast, not multicast.


Explicit isomorphism $S_4/V_4$ and $S_3$

Let $S_4$ be a symmetric group on $4$ elements, $V_4$ - its subgroup, consisting of $e,(12)(34),(13)(24)$ and $(14)(23)$ (Klein four-group). $V_4$ is normal and $S_4/V_4$ if consisting of $24/4=6$ elements. Hence $S_4/V_4$ is cyclic group $C_6$ or a symmetric group $S_3$ (really, there are only two groups consisting of $6$ elements). It is easy to see, that an order of each element of $S_4$ is $1,2,3$ or $4$. So, $S_4/V_4$ is isomorphic to $S_3$.  My question: how to build the isomorphism explicitly?


Postdoc without letter of recommendation

What if my PhD advisor doesn't want to give me a letter of recommendation, because he doesn't want me to leave on postdoc? None of his young assistants have ever been on any postdoc or fellowship exchange.


Can I fish Romex cable through concealed part of basement ceiling in Canada?

I am running two 2-wire and one 3-wire Romex cables from the panel in the basement to another part of the basement. For most of the run I have access to the ceiling joists, but I need to cross a 2.5 meter section which is closed off and contains lots of ducts and pipes.  Here's the obstruction. I am thinking of fishing cable between the joists on the top right of the picture:    And a look inside the space:   This means that I can't support the cable every 1.5 meters, but Rule 12-520 in CEC says:  Where the cable is used in concealed wiring and it is impracticable to  provide the supports required by Rule 12-510, and where metal sheeting  or cladding, metal joists, metal top or bottom plates, or metal studs  are not used, the cable shall be permitted to be fished.   So I just want to make sure that I understood this correctly. Can I fish the cable through, despite the fact that there are some metal ducts in the space?


Automatic grammar checker for LaTeX documents?

I'm currently writing a thesis. I'm using the Texmaker editor with the built-in dictionary for grammar correction (British English). Unfortunately, I'm short of time, so I don't have time to read everything again.  Texmaker only marks spelling mistakes. Is there a tool which can detect wrong or missing commas and perhaps weird sentences?


For any prime power $p^n$, prove that $\mathbb{Z}/p^n$ is an injective module over itself.


why does if statement not work in actionlistener

enter.addActionListener(new ActionListener() {          public void actionPerformed(ActionEvent e)         {             User = input.getText();              if (User == "hello") {                 Console = "Hi User!";             }              output.setText("User: " + User + "\n" + "Console: " + Console);         }     });         When I run it, it displays the text on the GUI. But why is it that the console doesn't respond. I did a system.out.prinln on User when I wrote "hello" Thats exactly hat it said, why is this if statement not working?


No more than 10,000 results are visible in search

If you make a search for something that returns more than 10,000 items in result. For example, search for  return 161,338 results on MSE. But if you select a page where 10,000+ result should be shown:        In the edge case  shows zero results:        But this is actual for any page where per_page * page_number is more than 10,000.  Though this does not happen for Stack Overflow in English. It looks like all other sites are affected.  Related bug report on ruSO.meta:


I know  works for 3 linear equations. I know all steps to get solutions. But I don't know why (how) Cramer's rule gives us solutions?   Why do we get $x=\frac{\Delta_1}\Delta$ and $y$ and $z$ in the same way?  I want to know how these steps give us solutions?


In the Walking Dead, do older more decrepit zombies retain their eyesight?

Whenever we see a close up of a zombie's face, their eyes always appear to be a , which would lead me to believe they are blind.  And, I'm assuming, they don't produce tears, so their eyes should be damaged beyond use anyway. But it seems as if they can see reasonably well, at least well enough to distinguish a person from something else.   They probably use sound and smell to track targets, but I've seen episodes where they are distracted by flares or fires, so they have to be able to see well enough to spot a fire in the distance.  This question :  addresses a zombie's senses and if they diminish over time. I would be more interested in older zombies, as their eyes should really be damaged beyond any use.  Is their eyesight ever addressed or explained in the show or in the comics?


There are plenty of guides on how to , but I can't find any on when to bother with it. Certain levels may have many of the same type of monster which will drop much of the same types of items (ex, ). Turn management can be critical in many places, say, bad circumstances, early game,  , , , etc.  Obviously, this can be highly circumstantial - say needing a particular drop -  but I'm more interested in the best general approach to the best general bell-curve of turns/circumstances vs items.  I'm also interested in addressing the item hoarder's fear: "I didn't try on every [common monster]'s drops - what if I missed something good?"   When should I be taking the time to identify items, and which items should I not bother with? What about cursed items? What about shops, which can have a wide variety of items? What about when there are hordes of the same monster?


In Photoshop, how can I open up a view (in the same window) with another zoom level?

When drawing pixel art in Photoshop, I like to have the zoom level really high.  Is there a way to also have a regular-level zoom (or perhaps an outer zoom) in another part of the window, so that I can see how the regular zoom will look as I work?


Do two creatures with protection from each other cancel out each others' protection?

I've been playing MtG for a while and recently came across protection from everything. It occurred to me: can two creatures with protection from everything block each other?  Or, can a blue creature with protection from red be blocked by a red creature with protection from blue?


I have a blender file where a sphere is orbiting a force field. I want it to be more red when it's closer to the center, and more blue when it's further. I already have the math figured out, I just need to know how to get x/y coordinates in nodes.  Here's the file:


I have the following -  function button_class_add() {     global $uno_dos;     $btn_shape_class = $uno_dos['buttons-shape-select-general'];     $btn_size_class = $uno_dos['buttons-size-select-general'];     ?>         <script type="text/javascript">             jQuery(function($) {                 $('.std-button').addClass('<?php echo $btn_shape_class $btn_size_class; ?>');             });         </script> <?php }  add_action('wp_footer', 'button_class_add');   How can I correctly combine these 2 variables so I can just echo out the combined variable?  $btn_shape_class = $uno_dos['buttons-shape-select-general']; $btn_size_class = $uno_dos['buttons-size-select-general'];   Many thanks  Combining these lines -  $btn_shape_class = $uno_dos['buttons-shape-select-general']; $btn_size_class = $uno_dos['buttons-size-select-general'];   Into something like -  $btn_shape = $uno_dos['buttons-shape-select-general']$uno_dos['buttons-size-select-general'];   Then I can just echo the 1 variable.


I swim every day/Monday.   But could I say:     I swim each day/Monday.   PS: I know there are already questions like , but please, try to understand my question before marking it duplicate without asking me if the other one replies to my question. I already read the other page, but I ask here if I can use it IN THE PRECISE EXAMPLES I HAVE GIVEN.   (forced to emphasize a lot, because very often people here read only half of the question, and mark it as duplicate)


Why does an overlap of atomic orbitals in a solid cause a continuous emission spectrum?

A given explanation for a light bulb's continuous spectrum of emitted light was that energy levels in solids overlap, therefore all energy changes can occur.   How can these changes occur? If an electron had enough energy to move into this 'overlap' space, how would it give out energy subsequently?  Can a spectrum ever be truly 'continuous'? Since the energy changes are just changes in discrete levels, tending towards a continuous distribution?


Can Kingsoft Office be installed in Ubuntu?


Basically, I want to make 3 concentric spheres with a portion of them being open (very similar to what is shown in the iamge).   I only know how to make concentric-like circles in Tikz, can someone help with making one similar to the image I posted?    Thanks!    Here is my starting code:  \documentclass[11pt]{article} \usepackage{tikz} \usepackage{pgfplots} \begin{document} \begin{figure}[h] \centering \begin{tikzpicture}[scale=1.4] \footnotesize \coordinate (A) at (2,0); \coordinate (B) at (5,0); \coordinate (C) at (6,0); %\coordinate (endt) at (12,0);  %draw the line \draw[-, very thick] (A) -- (C); \fill (A) circle (3pt) node[left=2pt] {A};  \fill (B) circle (3pt)  node[above=2pt] {B};  \fill (C) circle (3pt) node[right=2pt] {C};  \shade[ball color=blue!10!white,opacity=0.20] (A) circle (4cm); \draw[dashed] (2,4) arc (90:-90:2cm and 4cm); \draw[thick] (2,4) arc (90:270:2cm and 4cm); \draw[thick] (A) circle (4cm); %smaller circle \shade[ball color=blue!20!white,opacity=0.20] (A) circle (3cm);  \draw[thick] (A) circle (3cm); \draw[dashed] (2,3) arc (90:-90:1.5cm and 3cm);  \draw[thick] (2,3) arc (90:270:1.5cm and 3cm); \end{tikzpicture} \caption{Visualization of spatial distribution of A, C, and \B.} \end{figure} \end{document}


How is this Phone Number Validation work?

so I'm teaching myself jQuery recently and I just came to the chapter of AJAX. There is an example showing how to check the validation for phone number and I don't know what's going on and how it works. Here is the snippet of code:   // Validate a phone number field $( "#form" ).submit(function( event ) {     var inputtedPhoneNumber = $( "#phone" ).val();      // Match only numbers     var phoneNumberRegex = /^\d*$/;      // If the phone number doesn't match the regex     if ( !phoneNumberRegex.test( inputtedPhoneNumber ) ) {          // Usually show some kind of error message here          // Prevent the form from submitting         event.preventDefault();     } else {          // Run $.ajax() here     } });   What I don't understand is this:   var phoneNumberRegex = /^\d*$/;   I did some research for phone number validation and it all has something like this: a pair of "/ /" and some stuff between them and I've never seen this before, anyone can explain what is going on here and why it works? Any help will be appreciated, thank you!


Does an asteroid missing the ship give XP to the pilot & engineer?

I know that sitting in an asteroid field once you've dealt with the event there can level up the shield skill for a crewmember; they gain XP by restoring shield points, regardless of whether an asteroid or an enemy weapon damaged the shields.  When an asteroid misses me (the ship dodges it), do the crewmembers manning the Pilot & Engines consoles gain XP for their respective roles?


Find all postive integers $(a,b,c)$ ,  such that$a^2b-c,b^2c-a,c^2a-b$ are all powers of  2  someone can take a example such this condition


Java - Boolean not getting values in while loop

I am trying to use my function to check if I have a certain value in a text file and I am having a issue with my code. My Boolean is not picking up the values that I declared in my while loop. My code is below.  public static Boolean isValueExistant(String value) throws FileNotFoundException {     Scanner scanner = null;     Boolean h = null;     scanner = new Scanner(responses);     while (scanner.hasNextLine()) {         String lineFromFile = scanner.nextLine();         if(lineFromFile.contains(value)) {             h = true;             break;         } else {             h = false;             break;         }     }     return h; }   Calling function:  private static String askMessage() throws FileNotFoundException {         if(FileUtils.isValueExistant("Value name = ")){             String f5 = FileUtils.getValue("Value name = ");             System.out.print(f5.replaceAll("Value name = ", "")+": ");         }else if(!FileUtils.isValueExistant("Value name = ")){             System.out.print("You: ");         }     String input = sc.nextLine();     return input; }   I just get a NullPointerException on my Boolean because it isn't changing from the null value to the true or false. Thanks in advance!


save image in database or in server directory

I use java, tomcat, jsf and primefaces    and I have a field "image" in my product table and I 'd like to ask you which is better : save the image in the database or in one directory in the server  if the second case is the best, please explain me more how to manage it (I never had the opportunity to meet this case)  thank you in advance


Now dont get me wrong, i did everything i possible can to ensure that my smtp server is GOOD, i use high quality content so this is not content issue.  i never sent email to anyone besides my self for testing, and its all going to spam.  i have DKIM/SPF/_dmarc, google-dns-verification, PTR/Reverse proxy or w/e it called, it all set 100% working and i can see in gmail on the source tab that all PASS.  i checked my server on multiple testing websites such as:  and got 9.2  i checked that my IP is NOT blacklisted and its not.  i did everything i possible can to ensure my emails are OK but gmail still decides to throw me into spam (i tried to sent to 4-5 accounts not to one account only )  this is my email server -  teamsvoice.com / mail.teamsvoice.com  i installed iredmail included working SSL certificates anyone can think of Anything i haven't thought about?


What exactly is meant by "Ubuntu is based on Debian"?

Sorry if this seems like a silly question, but I thought about this recently. What does it mean when one distro is based off of another? Is it just the shared package manager, or are other features picked up from Debian in Ubuntu? What does Ubuntu add on to Debian?


I'm trying to figure out how to calculate the following angle:  I know center (p1) and radius (r) of a circle. Given a point p3 I want to calculate the angle a such as the tangent (tan) of the circle at point p4, points in p3 direction.  Here's a figure:    Doesn anyone know how to do that?


Prove if $\left\{x_n\right\}$ converges to $2$, then $\left\{\frac{1}{x_n}\right\}$ converges to $\frac{1}{2}$

We know that for all $\varepsilon > 0$, there exists an $N \in \mathbb{N}$ such that $\lvert x_n - 2 \rvert < \epsilon$ for all $n \geq N$, and we want to show that for all $\varepsilon' > 0$, there exists an $N' \in \mathbb{N}$ such that $\left| \frac{1}{x_n} - \frac{1}{2} \right| < \epsilon'$ for all $n \geq N'$.  Let $\varepsilon = \varepsilon' - \frac{3}{2}$. Then by the triangle inequality, we have $$\left| \frac{1}{x_n} - \frac{1}{2} \right| \leq \left| \frac{1}{x_n}\right| + \left| -\frac{1}{2}\right|.$$  Because we proved earlier that $x_n > 1$ for all $n \geq N$, we know that $$\left| \frac{1}{x_n}\right| + \left| -\frac{1}{2}\right| < \left| x_n\right| + \left| -\frac{1}{2}\right|.$$  By the triangle inequality again, we know that $$\left| x_n - \frac{1}{2}\right| \leq \left| x_n\right| + \left| -\frac{1}{2}\right|.$$  Note that $\left| x_n - \frac{1}{2}\right| = \left| (x_n - 2) + (2 - \frac{1}{2})\right|$, so we get $$\left| (x_n - 2) + (2 - \frac{1}{2})\right| \leq \left| x_n - 2\right| + \left| 2 - \frac{1}{2}\right|.$$  Then we have $$\left| x_n - 2\right| + \left|2 - \frac{1}{2}\right| < \varepsilon + \frac{3}{2} = \left(\varepsilon' - \frac{3}{2}\right) + \frac{3}{2} = \varepsilon',$$ so $\frac{1}{x_n} \rightarrow \frac{1}{2}$.  I just realized that I don't know how to make sure that $\varepsilon' - \frac{3}{2}$ is a positive number. How can I do this?


How to make tar extract to new directory with option to create directory if not present?

The tar command has option to extra a file (file_name.tgz) into given directory (directory_name). ie., tar -zxf file_name.tgz -C directory_name  But it fails, if I try to run the above command, without creating directory (directory_name) prior to running this. Following is the error I got: tar: directory_name: Cannot open: No such file or directory tar: Error is not recoverable: exiting now  Is there any option present in tar command to create this directory if not present? The present work around I have, is by running mkdir -p directory_name in prior.


Does gravity have a gauge symmetry group?

In the Standard Model, U(1) corresponds to the electromagnetic, SU(2) to weak, and SU(3) to strong interactions. I realize that gravity is not a part of the Standard Model. However, sometimes gravity is also viewed as a gauge theory. If so, does it correspond to any particular symmetry group or is this a wrong way of thinking and why?


I want to switch from win8 to Ubuntu but I'm stuck on the installation wizard partition management.   I've a 24gb ssd and a 750gb hdd, and I would like to have the "core" on the ssd and data on hdd, for maximum performances   how can I achieve this?


How can I time how long it takes a small block of C# code to execute?

I have this code:    var userId = Int32.Parse(User.Identity.GetUserId());   using (var context = new IdentityContext())   {       roleId = context.Database.SqlQuery<int>("SELECT RoleId FROM AspNetUserRoles where UserId = " + userId).FirstOrDefault();   }   Is there a very quick and simple way I could time how long this takes to execute. Even if the answer is put into a variable after this code block that would be enough as I can debug and see how long it took.


Let $V_m$ be the vector space of polynomials in $k[x_1,...,x_n]$ with degree at most $m$. Then what is the dimension of this vector space?   I can do this with m<4 maybe. But what is the general formula? It seems that this is a combinatorics problem. But I really do not have idea how to find a formula.


What are some good profilers for native C++ on Windows?

I'm looking for a profiler to use with native C++. It certainly does not have to be free, however cost does factor into the purchase decision. This is for commercial work so I can't use personal or academic licensed copies. The key features I'm looking for are:  Process level metrics Component level metrics Line-level metrics Supports Multi-threaded code Usability Cost Visual Studio 2005 Professional support required (VS 2008 Professional support highly desirable)  I've used Intel's VTune and Compuware's Devpartner Performance Analysis Community Edition. VTune seemed very powerful but it has a steep learning curve. It also is very "modular" so you have to figure out what parts are you need to buy. DevPartner PACE was pretty easy to use and provides all of the key features however it's only a 45-day trial. The licensed version (DevPartner for Visual C++ BoundsChecker Suite) is about $1400 a seat, which is doable but a bit high imo. What are some good profilers for native C++ and WHY?  See also:


Can a set that is closed under a binary operation have inverses for all of its elements.. without the existence  of an identity element?  My mind is telling me that in order to even have inverses, there needs to exist an identity element.  I am attempting to prove that the group Axioms 1)associativity 2)identity element 3) exisistance of inverse elements  are independent of each other, meaning you can't have 2 and imply the third one.


JavaScript Object is accessible outside scope but Type is not

Consider the following code snippet:  var OuterScope = function () {      function InnerScope () {         this.name = "K";         this.address = 10;     }      return new InnerScope(); };  console.log(new OuterScope());//Returns: InnerScope { name: 'K', address: 10 } console.log(new OuterScope().constructor.name);//Returns: InnerScope   Why/how does new OuterScope() returns the data? InnerScope is not defined in global namespace (where new OuterScope() is being invoked) yet JS properly recognizes the object/it's properties/constructor name etc.  Seems like returned data is parsed into JSON & JS interpreter in global namespace creates a JS object based on that JSON structure similar to what happens when we feed JSON data to client side from server side.


Why does my ssh login include what looks like a promotion for a TechRepublic article?

When I ssh into my Ubuntu box I see the output below. I was surprised to see the quote and the link to the TechRepublic article. Is that an advertisement? Anyone know where that is coming from? Is there any way to remove that? Thanks, Ben Welcome to Ubuntu 20.04 LTS (GNU/Linux 5.4.0-37-generic x86_64)   * Documentation:  https://help.ubuntu.com  * Management:     https://landscape.canonical.com  * Support:        https://ubuntu.com/advantage    System information as of Sun 21 Jun 2020 10:06:54 PM PDT    System load:  0.05                Processes:                249   Usage of /:   43.6% of 227.74GB   Users logged in:          0   Memory usage: 8%                  IPv4 address for enp0s25: <redacted>   Swap usage:   0%                  IPv4 address for wlp2s0:  <redacted>   Temperature:  56.0 C   * "If you've been waiting for the perfect Kubernetes dev solution for    macOS, the wait is over. Learn how to install Microk8s on macOS."     https://www.techrepublic.com/article/how-to-install-microk8s-on-macos/  0 updates can be installed immediately. 0 of these updates are security updates.


I want to have a bibliography at the end of each chapter (and later also at the end of the book).  In this MWE this does not work. I expected to have at the end "[1] A B, Test Journal ..." Bibtex runs with "Process exited normally".  \documentclass{book}  \usepackage[ngerman]{babel}  \usepackage[sorting=none, backend=bibtex]{biblatex} % load the package  \begin{filecontents}{bibliography_file.bib} @ARTICLE{myref,   AUTHOR       = "A B",   TITLE        = "Test",   JOURNAL      = "Journal",   YEAR         = "2019",   NUMBER       = "1" } \end{filecontents}  \addbibresource{bibliography_file.bib} % add a bib-reference file  \begin{document}  \chapter{First Chapter}  Hello. We cite \cite{myref}  \begin{refsection} % refsection environment Citation section \thesection: \cite{myref} % collect citations \printbibliography[heading=subbibliography] % print section bibliography \end{refsection}  \end{document}


Virtual particles, what do we mean by that?

This is probably more of a science philosophy question, but when we introduce those off-shell particles to explain some three body processes weird behaviour, do we really mean that there are actual massive stuff going on into the Compton length, or is it just a formal and mathematical way to make ours predictions correct? Given that the only real things are those who are measured, is there a difference between the two? I'm confused, because if virtual photons carry the e.m. field from an electrically charged body to another, can we directly measure it? Shouldn't we be able to directly "see" them? Do we? Thank you a lot for your patience


Trimming image-object to Size Equivalent to Photoshop

Is there a method in Blender equivalent to Photoshop, where you can select the image size to its exact dimensions? In this example I have attached the trim command in PS, where it automatically deletes the transparent pixels for the image to be exported. I usually export my object from blender with no background checking film. Then import into PS so I can see the actual pixel dimensions of the object since I cannot see pixel size in Blender.  Thank you.


Can I cast Blade Ward and then make my monk unarmed strike with a bonus action?

If my Monk uses an action to cast Blade Ward, can I use my bonus action to make an unarmed strike?


I have no photo ID issued by Government with me. Can I use an Affidavit with photo  duly sworn in before Notary can be A valid Photo ID. Is there  any  specific  language for such Affidavit.   Travel is domestic in India.


i have a server nodejs, when download a file from server  function download(info) {     var res = info.res;     var file = __dirname + '/static/downloads/abc.txt';      res.writeHead(200, {         'Content-Type': 'text/plain',         'Content-Length': stat.size     });      var readStream = fs.createReadStream(file);     readStream.pipe(res); }   I don't understand about how can i save file to the disk in client?


Do I need a transit visa to travel to Northern Cyprus?

I am a Ghanaian passport holder. Do I need a Turkish transit visa to travel from Moscow to the Turkish Republic of Northern Cyprus?


I have installed up to 2.6.1 of QGIS on my computer.    Is it recommended that i remove all older versions or will it cause conflicts if they remain?


Analog clock with same hands - sometimes one can't tell time

There is an accurate analog clock, however both hands are the same size and shape.  How many moments during a day a person can not conclude current time from the position of the hands?  This is from a competition, I was told it is a difficult problem.


I need a query to generate column names (and it's type if possible) of all tables in database.   Is there any simple way?


$J \neq 0$ ideal in $R=\mathbb{Z}[i]$. show that $J \cap \mathbb{Z}$ is an ideal in $\mathbb{Z}$

If $J \neq 0$ is an ideal in $R=\mathbb{Z}[i] .$ Then I need to show that $J \cap \mathbb{Z}$ is an ideal in $\mathbb{Z}$.  My approach (Or the way I wanted to approach the problem): In order for $J \cap \mathbb{Z}$ to be an ideal, I need to show it's an additive subgroup of $\mathbb{Z}$, and that $\lambda x\in J \cap \mathbb{Z}$; for every $\lambda \in \mathbb{Z}$ and $x \in J \cap \mathbb{Z}$. But I really don't know how to show it in such a general case, when I don't know anything about the elements in J. I hope you can help me.


How to set up reverse tethering over USB?

My HTC G2 phone is rooted and running Cyanogenmod 7 I don't have a data plan. Sometimes I want to connect the phone to the Internet when there isn't Wi-Fi, to update Market apps, backup SMS messages to Gmail, sync new contacts from Gmail, etc.  Things I can't do with USB mass storage mode. I have a Windows 7 Professional computer connected to the Internet, but I'm not allowed to set up an ad-hoc Wi-Fi network.  (If I do, they will notice and hunt me down.)   Is there a way for the phone to access the Internet through the USB connection to the computer?  If so, how do I set it up?


Removing blank page between list of figures and list of tables

i am using document class book. I have tried openany, oneside, cleardoublepage  But the blank page is not removed between two lists. My lists are quite lengthy though


Is there a way to see the previous query entered in a MySQL server through PHP? I do not want the results of the query, I want the actual plaintext query entered.


Recover hacked Gmail account where mobile numbers and alternative Gmail were changed

Someone hacked my Gmail account and now I can't access it. The hacker changed my alternative Gmail also, and phone number.    Is there any way I might recover my account?


I just downloaded the Windows 10 Ubuntu app. when I click on the app, it brings up a command line interface (I think interface is what it is called) but I do not know how to bring up the Ubuntu GUI. Is there a manual to tell how to start the app and open Ubuntu?


How execute commands of cmd in c# and return the values

How i can execute commands of cmd and return the values of this. For example, i execute the command Ipconfig and return a list of interface available Thanks.


What is the difference between these ways of declaring an array in Java? Is one of them better over the others?

int[] array = new int[] {1, 2};          int[] array2 = {1, 2};          int array3[] = new int[] {1, 2};          int array4[] = {1, 2};


Prove that the limit in probability of normally distributed random variables is normally distributed, too

Let $X_n\sim\mathcal N_{\mu_n,\sigma_n^2}$ for some $(\mu_n,\sigma_n^2)\in\mathbb R\times(0,\infty)$ and $X$ be a real-valued random variable with $$X_n\stackrel{\text{in probability}}\to X\;.\tag 1$$     How can we prove that $X\sim\mathcal N_{\mu,\sigma}$ for some $(\mu,\sigma)\in\mathbb R\times(0,\infty)$?   That's what I've done: By $(1)$ and  we obtain $$X_n\stackrel{\text{in distribution}}\to X\tag 2$$ and thereby $$\operatorname E\left[f(X_n)\right]\stackrel{n\to\infty}\to\operatorname E\left[f(X)\right]\;\;\;\text{for all bounded }f\in C^0(\mathbb R)\tag 3$$ by the . Especially, since $$\mathbb R\ni x\mapsto e^{{\rm i}x}=\cos x+{\rm i}\sin x$$ is continuous and bounded, $$\varphi_{X_n}(t):=\operatorname E\left[e^{{\rm i}tX_n}\right]\stackrel{n\to\infty}\to\operatorname E\left[e^{{\rm i}tX}\right]=:\varphi_X(t)\;\;\;\text{for all }t\in\mathbb R\tag 4\;.$$ $\varphi_{X_n}$ and $\varphi_X$ are the characteristic functions of $X_n$ and $X$, respectively. Now, we should be close since a finite measure on $\mathbb R^d$ is uniquely determined by its characteristic function.  However, I'm not able to conclude. Please note that I'm not primarily interested in $(\mu,\sigma)$ and the relationship to $(\mu_n,\sigma_n)$. I just want to show that $X$ is normally distributed. However, if it's easy to obtain, I wouldn't be angry if someone could prove the relationship too.


List of ways to tell if degree sequence is impossible for a simple graph

I'm trying to make a list of ways to tell if a given degree sequence is impossible. For example $3,1,1$  is not possible because there are only 3 vertices in total so one can't have degree 3.  The list so far   vertices has degree equal to or larger than number of vertices sum of degrees is odd for n vertices if one has degree n-1 and another has degree 0 for n vertices the sum of the degrees cannot be greater than $n(n-1)$ because this would be have more edges than a complete graph


Is it possible that dark-matter is composed of a large number of neutrinos from the big bang?

They seem to have all the properties of dark-matter (massive, with no electromagnetic interaction). Could it be that many of the neutrinos produced since the big bang have formed massive neutrino clusters that act as dark-matter?


When I cat a pid file I get a %,why and what that means?

I googled, but it ignore the "%". all about pid. My system is macOS. Here's the code: cat /usr/local/var/run/php-fpm.pid #I got this. 7260%   #When I use vim open it. only have text "7260" 7260  Could you tell me why ? Thank you very much.


Find the limit $\lim_{n \to \infty}\frac1n\sum_{k=0}^{[\frac{n}{2}]}\cos\left(\frac {k\pi}{n}\right)$

Evaluate:  $$\lim_{n \to \infty}\frac1n\sum_{k=0}^{[\frac{n}{2}]}\cos\left(\frac {k\pi}{n}\right)$$ Where $[\frac {n}{2}]$ denotes Largest Integer not exceeding $\frac{n}{2}$.  I thought much about this problem but couldn't found any way to handle this,So I need your help to handle this. Thanks in advance.


Prove that in each year, the 13th day of some month occurs on a  Friday.  No clue... please help!