Why did FIPS become the AES Standard . What is wrong with Twofish and Serpent ? Is there a security vulnerability in Twofish / Serpent ? How do thy work ? As far as i know Twofish and Serpent are used in Some modern encryptions .  Sorry for the dumb question . I am only 16 and I dont really know much about Cryptography .

I was just reading the  and came across an interesting table explaining how the winner was chosen:    Unfortunately the NIST site is down so I can't gain further information about the approval process so I was hoping someone here would know in more detail.   Who or what decided on the numbers in this table which ranks each algorithm? I.e. can the exact analysis process be described? Who created that process? People in NIST or an equally divided group of government, industry and public cryptographers? What is included in "Design Features"? I.e. What were those features that were important? "Performance" analysis could have been done with benchmarks but "Implementation Difficulty" sounds subjective. How was that quantified? Could the numbers in that table been tweaked to skew the results in favor of a particular algorithm?   Those questions aside and assuming the magic numbers above were arrived at a fair and equitable process without bias or hidden agendas, it seems to me this table or ranking system is still missing a "weighting" criteria. All categories seem to be weighted with the same importance. That is "Smart Card Performance" is equally important as "General Security". That seems incorrect. I would argue that security is of the utmost importance so that should have a higher weighting relative to the other criteria which would be secondary concerns. A good quote would be:     Security at the expense of usability, comes at the expense of security.   I wondered what would happen if I applied a high weighting factor to security and left the other points as they are. For example:    Now Serpent is first equal with Rijndael with Twofish coming in a close second. Interesting.  What about if I am developing a software product, I don't care about about hardware performance or smart card performance so I can rule those two out completely in my decision. The table might look like this:    Now Twofish is the winner and Rijndael is second equal with Serpent and MARS. MARS might even be more attractive with its variable key size up to 448 bits.  My overall point is that Rijndael, Serpent, Twofish and MARS all appear to be within the same ballpark quality range as far as block ciphers go and this rating criteria. There might be a more accurate mathematical way to apply a weighting factor. If I was revamping the security on a project and concerned about NSA involvement in weakening encryption standards then I could re-weight some of the criteria and priorities to suit my project's specific goals. I might decide on a different algorithm from Rijndael. Back in 2000 Rijndael might have suited the US government's purposes and planned surveillance agendas but not my project's. I would compare it to selecting an algorithm just like TrueCrypt gives you the option of choosing between 3 different algorithms. Would that be a reasonable call?


I have markers on pressing to which popup has to be brought. how to make it? (coordinates of markers undertake from a DB)  var map; var markers;   function ejecutar() {     init(3);     //loadMarkers(); } function init(b,kor_1,kor_2) {     if (b == 3) {         map = new OpenLayers.Map("basicMap", {             controls: [                 new OpenLayers.Control.Navigation(),                 new OpenLayers.Control.PanZoomBar(),                 new OpenLayers.Control.LayerSwitcher(),                 new OpenLayers.Control.Attribution()],             maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34, 20037508.34, 20037508.34),             maxResolution: 156543.0399,             numZoomLevels: 2,             units: 'm',             projection: new OpenLayers.Projection("EPSG:900913"),             displayProjection: new OpenLayers.Projection("EPSG:4326")         });     }      layerMapnik = new OpenLayers.Layer.OSM.Mapnik("MapaCiudad");     map.addLayer(layerMapnik);     var lonLat = new OpenLayers.LonLat(50.5206298828125, 55.15881723298661).transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject());     //map.setCenter(new OpenLayers.LonLat(-3.862788677215576, 43.4669443349282) // Center of the map     map.zoomTo(9);     map.setCenter(lonLat, 19);       //создаем дорогу      var lineLayer = new OpenLayers.Layer.Vector("Линии");      map.addLayer(lineLayer);                         map.addControl(new OpenLayers.Control.DrawFeature(lineLayer, OpenLayers.Handler.Path));      var points = new Array(        new OpenLayers.Geometry.Point(37.61556, 55.75222),        new OpenLayers.Geometry.Point(45, 33),        new OpenLayers.Geometry.Point(49, 35),        new OpenLayers.Geometry.Point(45, 56),        new OpenLayers.Geometry.Point(49, 87)     );      var line = new OpenLayers.Geometry.LineString(points);     line.transform(new OpenLayers.Projection("EPSG:4326"), new OpenLayers.Projection("EPSG:900913"));      var style = {          strokeColor: '#0000ff',          strokeOpacity: 0.5,         strokeWidth: 5     };      var lineFeature = new OpenLayers.Feature.Vector(line, null, style);     lineLayer.addFeatures([lineFeature]);       var popup = new OpenLayers.Popup.FramedCloud(              "popup",              OpenLayers.LonLat.fromString(feature.geometry.toShortString()),              null,              '
'+feature.data.Name + '
test.url' + '
',              null,              true          );      //добавление на карту      map.addPopup(popup, true);        //создаем маркер     markers = new OpenLayers.Layer.Markers("Marcadores");     map.addLayer(markers);      if (b == 2)      {                         //=================  =========стили для маркеров и тут хранятся координаты             var size = new OpenLayers.Size(30, 30);             var offset = new OpenLayers.Pixel(-(size.w / 2), -size.h);              var location = new OpenLayers.LonLat(kor_1, kor_2).transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject());             var icon = new OpenLayers.Icon('http://icons.iconarchive.com/icons/icons-land/vista-map-markers/256/Map-Marker-Ball-Pink-icon.png', size, offset);             markers.addMarker(new OpenLayers.Marker(location, icon.clone()));          }   }                        function add_metka()     {         function dobavit(koor1, koor2)         {              init(2,koor1,koor2);         }       @foreach (Дорожное_строительство.Models.koordinats_piket picket  in ViewBag.Data)     {     <text>         dobavit(@picket.Dolgota,@picket.Shirota);            </text>     }      }      setTimeout('add_metka()', 6000) </script>

Is it possible to customize the shape of popups in OpenLayers? For example, I am creating a pop-up using the following approach:  var popup = new OpenLayers.Popup.FramedCloud(                 "popup",                 OpenLayers.LonLat.fromString(feature.geometry.toShortString()),                 null,                 '
'+feature.data.Name + '
test.url' + '
',                 null,                 true             );   This creates a popup with the following appearance:    Is it possible to change from the rounded corners and a curved 'connection' to a more square pop-up?


Is there a way to count number of features for each data driven and reflect it in the legend?

I have made a series of  in ArcMap 10. When I classify the interval the bottom of the dialogue tells how many elements are in the class.  Is it possible to have this number automatically places beside my class labels?


Hi I am from India and have B1 . Can I come to US without a B2 visa. I had previously used this visa for official purpose. Will there be any problem relating to immigration. I will be staying with my friend what other formality do I have to do?

I got a B1/B2 visa earlier this year when I traveled to the US for a business trip from my company. It expires in 2013 and I'd love to visit the United States again, but for no other purpose than traveling.  I wonder:        If I can legally travel to US with B1/B2 visa without a real business need (assuming I'm honest);   If I have to work at my current company to be able to use it.      I live in Russia.


I have a C++ project with 5 files:  sde.cpp (containing main()), sde_library.cpp, sde_library.hpp, num_vector.cpp and num_vector.hpp. I'm trying to compile them together with the command  g++ sde.cpp sde_library.cpp num_vector.cpp -o sde.out   The main function contains the two lines  int test = 0; vector<vector<double>> avg_trace = RK_all(num_traces, many_traces, t_interval, y0, dt, test);   And this function is declared in sde_library.hpp as  template<typename eq_params> std::vector<std::vector<double>> RK_all(unsigned int num_traces,  bool many_traces, std::vector<double> t_interval, std::vector<double> y0, double dt, eq_params args);   The implementation is found on sde_library.cpp. However, when compiling I get the following linker error message:  /tmp/ccZkiXkj.o: In function `main':  sde.cpp:(.text.startup+0xd5): undefined reference to `std::vector<std::vector<double, std::allocator<double> >, std::allocator<std::vector<double, std::allocator<double> > > > RK_all<int>(unsigned int, bool, std::vector<double, std::allocator<double> >, std::vector<double, std::allocator<double> >, double, int)'  collect2: error: ld returned 1 exit status   I was assuming that the appearance of this error was due to me introducing templates to the function RK_all (before I introduced that it was running correctly); I've seen that "undefined references" appear with templates and it's the first time that I'm using them. However, in the main I'm explicitly stating that eq_params will be of the int type, so the compiler should understand what this template is. Is that correct? What am I missing, or what else could it be? And how would I fix that?

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


The formula of Pythagorean triples is $(a^2+b^2)^2=(2ab)^2+(a^2-b^2)^2$ and a list can be build up with $a^2+b^2$ monotonically increasing. The Pythagorean triples should be primitive here which means $\gcd(a,b)=1$.  The list is $5^2=4^2+3^2$,  $13^2=12^2+5^2$,  $17^2=15^2+8^2$, … and so on.   Be $\#(n)$ the number of primitive Pythagorean triples with $n:=a^2+b^2$.   If $\#(n)$ has several values, e.g. $\#(85)\in\{13;14\}$, than choose the minimum, here $\#(85)=13$. To get $\#(n)$ one counts in the list all triples with $a^2+b^2\leq n$.    How can be proofed $$\lim\limits_{n\to\infty}\frac{n}{\#(n)}=2\pi$$ ?  It was proofed by Derrick Norman Lehmer, but I cannot find his proof.

i just read "mathematical constants" book;  it said that Lehmer proved the following theorem in 1900    where P_h(n) , P_p(n) is number of primitive Pythagorean triangles whose hypotenuses and perimeter do not exceed n respectively.  is there any simple proof for those beautiful results? Specially The first one!


Is there a way to typeset the following matrix in LaTeX?    In my attempt, I got to the following:  \begin{equation} C=\left[\begin{array}{cccccccccc} 1 & 1  & 1 & 0 & \ldots & \ldots & -1 & -1 & -1\\ 1 & 1  & 1 & 1 & \ldots & \ldots & \ldots & -1 & -1\\ 1 & 1 & \ldots   & 1 & 1 & \ldots & \ldots & 0 & -1\\ 0 & 1 & \ldots & \ldots  & 1 & 1 & \ldots & 0 & 0\\ \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\ \hdotsfor{9}\cr\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots &\vdots &\vdots  \\ -1 &0 & \ldots & \ldots & 0 & 1 & 1 & 1 & 1\\ -1 & -1 & 0 & \ldots & \ldots & 0 & 1 & 1 & 1\\ -1 & -1 & -1 & \ldots & \ldots & \ldots & 0 & 1 & 1 \end{array} \right] \end{equation}   Would like to know how to add the curly braces.

I want to make an overbrace and a side brace on my matrix in order to indicate its size. How can I achieve that.    \begin{pmatrix}   1 & 1 & 0 & .& . & . & 0 & 1  \\   0 & 0 & 1 & .& . & . & 1 & 0 \\  .\\  .\\  .\\   0 & 1 & 1 & . & . & . & 1 & 1  \end{pmatrix}


I have server on 2 ssd disks connected by Raid 1  Today I got 500 internal error on opening website. I have requested server management to reboot the computer.  After reboot to my surprise all my directories, files, sql databases after July 2013 went missing. So effectively all data from July 2013-May 2014 can't be seen.  Please suggest what are my options, do you think my data is wiped out and if there are ways to recover it.

When someone mentions RAID in a conversation about backups, invariably someone declares that "RAID is not a backup."  Sure, for striping, that's true. But what's the difference between redundancy and a backup?


here are the headers of the blocked messages (actual domain replaced with domain.com, ip address with n.n.n.n and gmail account name with person.account):  Delivered-To: person.name@gmail.com Received: by 10.216.89.137 with SMTP id c9cs247685wef;         Tue, 6 Dec 2011 16:06:37 -0800 (PST) Received: by 10.224.199.134 with SMTP id es6mr14447757qab.2.1323216395590;         Tue, 06 Dec 2011 16:06:35 -0800 (PST) Return-Path: <notifications@domain.com> Received: from mail.domain.com (domain.com. [n.n.n.n])         by mx.google.com with ESMTP id b16si7471407qcv.131.2011.12.06.16.06.35;         Tue, 06 Dec 2011 16:06:35 -0800 (PST) Received-SPF: pass (google.com: domain of notifications@domain.com designates n.n.n.n as permitted sender) client-ip=n.n.n.n; Authentication-Results: mx.google.com; spf=pass (google.com: domain of notifications@domain.com designates n.n.n.n as permitted sender) smtp.mail=notifications@domain.com Received: by mail.domain.com (Postfix, from userid 5001)   id 26ADE381E3; Tue,  6 Dec 2011 19:06:35 -0500 (EST) Received: from domain.com (domain.com [127.0.0.1])   by mail.domain.com (Postfix) with ESMTP id 0148638030   for <person.name@gmail.com>; Tue,  6 Dec 2011 19:06:31 -0500 (EST) Date: Tue, 06 Dec 2011 19:06:31 -0500 From: DomainApp <notifications@domain.com> Reply-To: notifications@domain.com To: person.name@gmail.com Message-ID: <4edeae07e069c_7cc1413de46597b2@domain.com> Subject: Roman Snitko says hi Mime-Version: 1.0 Content-Type: text/plain;  charset=UTF-8 Content-Transfer-Encoding: 7bit X-No-Spam: True Precedence: bulk List-Unsubscribe: notifications@domain.com   Messages go to Spam folder on various gmail accounts, so it's not a coincidence.  I followed all gmail guides on sending bulk emails from here . I also checked my ip-address here  and it's NOT on the blacklists.  Thus I have two questions:   What may be the possible reason for the messages to go to Spam folder? Is there any way to contact Google and ask them what causes this?   Update: I have set up openDKIM on my server, everything works, gmail message headers say that dkim=pass, which means everything is set up correctly. Messages still end up in Spam folder.

I work for an educational services company based in India. We've around one million students enrolled as users. We're frequently facing the problem of our bulk mailers regarding upcoming exams, new product launches and promotions going into spam mail folders of the students. Is the problem in the headlines? Or where else? what can we do to reduce this number?   This is killing us, we cannot have an impossibly large precentage of mails not being opened..Please help.


When using the GUI and making actions I think that users would like to see how those actions are being reflected in the terminal using command lines.   I can imagine that there are different layers of commands/processes that could be reflected which are endless but lets keep it simple and in direct relation to the end user GUI experience.  Examples:    opening an applications such libreoffice or web browser... browsing home folders and copy, cut, paste... Network manager changes such as wireless up, down and wired up, down... and so on...   This would satisfy curiosity and also help as a teaching/learning tool for those curious about the command line. Do others see this need? Does this already exist and if not would this be feasible for an end user teaching experience?

I am new to Linux and only know my way around because of the GUI.  Is there a way to see the equivalent commands on the terminal to do the same things as using the GUI?  Thanks


A binary tree can have at most two children.  Two trees are called isomorphic if one of them can be obtained from other by a series of flips, i.e. by swapping left and right children of a number of nodes. Any number of nodes at any level can have their children swapped. Two empty trees are isomorphic.  The idea is to create an array of integers whose $i^{th}$ term will store number of such tree with $i$ nodes.

I am trying to calculate the number of trees (non isomorphic)  with $n$ nodes (total including leaves).  I think that there are n! such trees, but I don't know how to prove that.  I know that the number of trees with n internal nodes is a the $(n-1)$th catalan number, so I thought maybe there is a way to deduce from that the number of trees with $n$ total nodes.   another approach will be to look at each level and count the number of possible nodes in each level.


There are many discussions about the current incidence. For example:          Should we have a whole tag for this incidence? In general, if in the future there are more crises and incidences like this, should they have their own tags too? I feel it's fine, as we have specific tags for individual events like . And, should we have a  tag?    Related:        Note that these questions are specifically about the conflict 2019, while this question is simply about creating meta tags for significant events.

Question description  There are many questions (~250 in the last five weeks) relating to      sometimes they are about licensing, legal issues, , , , etc.  These questions relate to the same growing polarization between community and Stack Exchange staff. But, it is not easy to search or filter them because the tags are not uniform for those questions, they do not have the same tags.  Could we group all these posts together by some common tag (new or not)? (in addition, maybe we should create less of these questions, they tend to become noise now, water down the core message, and it is ).    Relevance  Overview of current tags (aside from the discussion tag) for the first ten  (           ) questions relating to  (ordered by relevance)                              1   2   3   4   5   6   7   8   9   10     moderators              x           x   x   x     community               x           x   x     etiquette                   x     users                       x     company                     x     moderation                      x     code-of-conduct                     x       x       x     deleted-questions                               x     legal                                                   x   These tags are obviously not the same while it is arguably the same topic (it is even for the same, specific, search term) .  Instead of using multiple searches one might wish to control tracking these question by adding some single relevant tag to watched tags or ignore tags. But, this is difficult when they do not use the same tag. And in the case of ignoring one might ignore too much when the tag is not specific.  Another indicator that these posts need consistent tagging is the fact that there exist highly upvoted answers that function as an archive for these questions (see  and ). But it is only a hack/workaround for the absence of a common tag; they are not an optimal solution.    Why now?  In an older question () it was suggested to create a specific tag. That was rejected at that point. But, now we are several weeks, and many many questions, further. The situation is more escalated than what might have foreseen at that point. The overview becomes a mess and something needs to be done.  See the bump in the image below which indicates that something is 'going on' and it entails a large fraction of the current post. (obtained from )


Let $I \subset \Bbb R$ be an interval and $λ : I → \Bbb R$ be a solution of the differential equation $\dot x = f(t, x)$, where $f : \Bbb R × \Bbb R → \Bbb R$ is continuous. Suppose that a differentiable function $α : I → \Bbb R$ satisfies $\dot α(t) > f(t, α(t))$ for all $t \in I$, and we have $α(t_0) ≥ λ(t_0)$ for some $t_0 ∈ I$. Show that α(t) > λ(t) for all $t ∈ I$  with  $t > t_0.$  Begining of the solution that I got : Define $d(t) := α(t) − λ(t)$ for all $t ∈ I$ with $t ≥ t_0$. The assumption implies that $d(t_0) ≥ 0$. Assume for contradiction that d(t) ≤ 0 for some $t > t_0$ and define $τ$ := inf {  t > $t_0$ : d(t) ≤ 0}  My question is: why does this imply that $d(τ) = 0$

Here is something I'm trying to prove:     Conjecture: Suppose $f'(x) \leq \phi(f(x), x)$ and $f(a)=\alpha$. Suppose $g'(x)=\phi(g(x),x)$ and $g(a)\geq \alpha$. Then $f(x)\leq  g(x)\,\,\forall x$.   It definitely seems like it should be true, and I don't think we even need continuity of $\phi$.  (Edit: a user has correctly pointed out that we should require $\phi$ be locally Lipshitz in the first variable, uniformly with respect to the second variable. Let's add that assumption.)   I can prove it in the case that the inequality is strict. I'll place my proof below the fold. How can I extend it to weak inequality?  If it's wrong, I'd love to see a counterexample. A reference is fine; I have the book by Teschl, for example.  A similar question with stronger assumptions was asked .     Proposition: Suppose Suppose $f'(x) < \phi(f(x), x)$ and $f(a)=\alpha$. Suppose $g'(x)=\phi(g(x),x)$ and $g(a)\geq \alpha$. Then $f(x)\leq  g(x)\,\,\forall x$.  Proof: Suppose not. Suppose WLOG there is a $b>a$ such that $f(b)>g(b)$. Let $c:=\inf \{x>a:f(x)>g(x)\}$. By definition of the derivative we have $f'(c)\geq g'(c)$, a contradiction, since $f'(c)<\phi(f(c),c)=\phi(g(c),c))=g'(c)$.


If $M(\epsilon)$ is the $\sigma$-algebra generated by $\epsilon$, then $M(\epsilon)$ is the union of the $\sigma$-algebras generated by $F$ as $F$ ranges over all countable subsets of $\epsilon$  Proof: Let $M = \bigcup_{F\subset \epsilon}M(F)$, we need to show that $M = M(\epsilon)$. First, we will show that $M\subset M(\epsilon)$, observe that for each countable subset of $F$ of $\epsilon$ that $M(F)\subset M(\epsilon)$. Since, $F\subset \epsilon \subset M(\epsilon) \Rightarrow M(\epsilon)$ is a $\sigma$-algebra containing $F$ therefore $M(F)\subset M(\epsilon)$.  Now we need to show $M\subset \epsilon$ but this is where I am sort of lost, any suggestions is greatly appreciated. I know this is similar to another question that was asked but I didn't really like the notation and I wish to follow through with what I have set up already

Suppose $\mathcal{A}$ is a $\sigma$-algebra generated by $\mathcal{E}$. Then $\mathcal{A}$ is the union of the $\sigma$-algebras generated by $\mathcal{F}$ where $\mathcal{F}$ ranges over all countable subsets of $\mathcal{E}$  I am kind of confused when the propostion says "ranges over all countable ... "  Am I asked to show that   $$ \mathcal{A} = \bigcup \{ \mathcal{M} : \mathcal{M} = \sigma( \mathcal{F}), \mathcal{F} \; \; \text{countable subset of $\mathcal{E}$} \} \text{ ??}$$


Let's say I have a PDF on my computer with information relating to my question that I cannot find elsewhere on the Internet.  Is it possible to link the PDF to a question or an answer I post on one of the Stack Exchange. network posts?

I want to attach some files to a post on one of Stack Exchange sites. What is the best way to do this?


Mainly curious about coding style - why is it sometimes better to place implementation in header like for example QVector:    the cpp is totaly empty

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


So far my hunch is that for all the numbers of the form $p^r$ where $p$ is any prime number and $r$ is any positive integer would dissatisfy the above condition. So all numbers not of this form should be the answer. But I don't have any concrete proof just few test cases for small numbers and the idea that $\frac{n^2!}{n!^n}$ is an integer for all $n$. The last $n^2$ is used to cancel out the last $n$ from denominator. Kindly help.

Question: Find all positive integers $n$ such that $(n^2 - 1)!$ is a   multiple of $(n!)^n$.   I can show that the required condition fails if $n$ is a prime, and by direct computation, it also fails for $n=4$. After doing a few small examples by hand, I believe that the required answer is 1 and all composites greater than 4. However, I cannot seem to prove this.  For each prime $p<n$, I tried to count the number of appearances of $p$ on both sides, but I get that I am supposed to compare $n(\lfloor{\frac{n}{p}} \rfloor + \lfloor{\frac{n}{p^2}} \rfloor +\dots)$ against $\lfloor{\frac{n^2-1}{p}} \rfloor + \lfloor{\frac{n^2-1}{p^2}} \rfloor + \dots$, which is not obvious to compare.  Any help will be gretaly appreciated.


I was trying to find the setting to disable the wallpaper on my Android phone. I've found some suggestion which suggest to make a fake black png or something like that, but it's going around the problem instead of solving it. Technically, it's still a wallpaper, and I don't want to have any...  How to set not to use wallpaper on Android? There must be some way, even on Windows it's possible...  I'm using Samsung Galaxy S4

My android comes with 3 different solid wallpapers. I have found more in the market but its paid. How to get a black wallpaper for free?


I have an RTX 2070 Super with Amd 3700x. I have optix enabled and it denoises the viewport render which is fine. However when I go to render out the image it begins denoising on the second pass and looks fine, but when the render finishes the noise comes back to the image as if it hadn't been denoised despite the denoiser working until it finished. I have tried turning alternating with cuda on and off on gpu and cpu in the preferences as well as changing the passes to color and albedo with and without normals. I cant seem to find any answer for this problem online, I will keep looking in the meantime. But if anyone has any idea what might be going on I would greatly appreciate the help.  render on second pass without noise  finished noisy render

After enabling Denoising Data pass, there are now two image outputs:  Image Noisy Image  Which should I use with the Denoise node?  doesn't cover it.


I am very new to electronics and hardware.  I want to know how can i convert 9v to 5v and 3.3v using only resistors ?  Basically, this is what i am trying to do -  I want to supply power (3.3v) to an . And, i want to supply power (5v) to a soil moisture sensor. (The soil moisture sensor will be connected to the esp module.)  But, i have only one 9v battery to supply power to both.  I want to do this using resisitors. Is it possible ? If yes, how ?  Thanks in advance.

I have been looking around for an easy way to convert 12V to 5V. I have seen some people saying that a simple resistor is all that is needed.  $$ Volts = Ohms \cdot Amps $$ $$ Amps  = \frac{Volts}{Ohms} $$ $$Ohms  = \frac{Volts}{Amps}$$  So applying a resistor will diminish the voltage of the circuit. That should mean that an appropriately sized resistor could simply be placed in the path of a 12V circuit, converting it to 5v.   If this is the case how would one reduce amps? Would series vs parallel make a difference in this area?   I have seen designs that include a regulator IC and some capacitors, but if a simple resistor/fuse/diode setup will do the trick, I would really prefer that.


Claim  Let A is well-ordered set.  $C \approxeq A$ or $C \approxeq section \;of \;A$ $\forall C$ s.t. $C \subset A$   How to prove above claim?

Claim  Let A is well-ordered set.  $C \approxeq A$ or $C \approxeq \text{section of } A$ $\forall C$ s.t. $C \subset A$   Proof  If $C=A$, $C \approxeq A$ since a well-ordered set is order-isomorphic to oneself.  If $C \neq A$, there $\exists a \in A$ s.t. $a \notin C$. Then   $A\setminus C = \{a \in A \;|\;a \notin C\}$.  Now, since A is well-ordered, there $\exists$ least element in $A\setminus C$, so let this least element be $m_0$.  Now let $S_{m_o} = \{a \in A \;|\; a< m_0\}$ which is a section of A.  Now define $\phi : C \to S_{m_0}$ s.t. $\forall C_0, C_1 \in C$ if $C_0 \le C_1$ then $\phi(C_0) \le \phi(C_1)$   There $\exists \;\text{such}\;\phi$ since $C$ and  $S_{m_0}$ are all-well-ordered since A is well-ordered.  So by definition $\phi$ is increasing. Also, $\phi$is bijective since the number of element in $C$ and $S_{m_0}$ is equal.  Thus,  $\phi^{-1}$ also exists and it is also increasing and bijective by definition.  Thus $C \approxeq \text{section of } A$


If I look on nutritiondata.self.com for the nutrition value of raw lentils (as an example), it tells me the . However, 1 cup of boiled lentils is good for !   I looked up the question, however the popular answer is that . But judging by those numbers, I think that it does!   So, what should I do?  Lentils being just an example! This applies to other foods too..

I like to cook from scratch, and I'm currently trying to loose a few pounds. I know that cooked food is generally more calorific than raw food, so if I add up the calories of the ingredients I know it won't give an accurate result.  So my questions are two-fold:  How much difference is there between a raw food item and a cooked food item?  Is there a method to deduce the calorie content of cooked food (given the know values of its raw form) ?


Find the limit: $$\lim_{x\to0^+}{x^x}$$  *This question appeared in a calculus exam, and I would like to see different approaches and solutions to the problem.

I was wondering what is the value of $\lim\limits_{x\to 0+} x^{x}$.  Assuming that the limit exists, I could show using the usual logarithm techniques that the limit is $1$. However, I am not able to show that the limit exists. Could some one help on that?  EDIT: It would be so nice if we could do it without l'Hopital...


I was reviewing a question in the Reopen queue on Stackoverflow where someone who had edited the post had a hat on their profile picture:  At the time I had the "(more)" dialog open:  When I clicked (less) to hide the dialog, the hat of the user who edited the post remained where it was (as well as being redrawn in the new position):  I'm using Firefox 83.0 on Windows 10.

It seems like there is a bug that is causing a duplicate hat to appear when I expand info, like pressing "(more)" on a suggested edit. This bug does not seem to be specific to the suggested edits review queue though, as others have reported seeing this bug in other places, like code snippet expansion. Steps to repro:  Put on a hat. Navigate to one of your own suggested edits. (You can just also open the Suggested Edits review queue and go to a random suggestion, but there is no guarantee any of those users will be wearing a hat.) Click the "(more)" button to expand the top box.  What should happen: Hat should shift down with the rest of the content. What happens: All the content shifts down, but a duplicate hat remains in the initial place. Before expansion:  After expansion with duplicate hat:


I've got an old pc with windows XP 32 bit, and I wanted to turn it into a home based server.  I am thinking of installing ubuntu as an OS.  I'm a networking novice so I'm not quite sure if it will work good.  My other computers are all running windows 7 64 bit.  So, will it be sufficient to turn this 32 bit box into a server to hold all my files and backups, while the 64 bit pc's just exchange the data?  Please let me know, or educate me on the subject.  Thanks in advance.

What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them.  If so, why not promote 64-bit over 32-bit?


Let $U$ be the open right half-plane. Suppose $f$ is a nonzero analytic function on $U$ whereby there exists $\theta \in (-\frac{\pi}{2}, \frac{\pi}{2})$ such that  \begin{equation}\lim_{r\to \infty}\frac{\ln |f(r\exp(i\theta))|}{r}= - \infty.\end{equation}  Then $f$ is unbounded.  It feels to me like it’s an application of Hadamard three-circle theorem.

Let $\Omega$ be the right half plane excluding the imgainary axis and $f\in H(\Omega)$ such that $|f(z)|<1$ for all $z\in\Omega$. If there exists $\alpha\in(-\frac{\pi}{2},\frac{\pi}{2})$ such that $$\lim_{r\rightarrow\infty}\frac{\log|f(re^{i\alpha})|}{r}=-\infty$$ prove that $f=0$.  The hint is define $g_n(z)=f(z)e^{nz}$, then by previous exericise $|g_n|<1$ for all $z\in\Omega$.


“Electromagnetic radiation which, according to theory, should be emitted by a black hole. The radiation is due to the black hole capturing one of a particle-antiparticle pair created spontaneously near to the event horizon.” (General definition of Hawking Radiation)   I have several questions concerning this…..  Once one of the virtual particles is swallowed by the by the event horizon, the surviving particle becomes a real particle.  The generally accepted theory is that the black hole provides the energy needed to allow this to happen.  Wouldn’t any energy syphoned from the singularity need to travel faster than light to achieve this?  I mean light cannot escape the black hole as it cannot travel faster than C.  This means that any energy from the singularity has to first escape the massive gravity field / warped space time.  It also has to travel the distance from the singularity to through the event horizon to the particle nearly instantaneously.  How is this possible?  This would appear to violate General Relativity wouldn't it?  Why are not both particles drawn into the black hole?  If the virtual particles pop into existence so close to each other to be instantly annihilated by each other, shouldn’t they both be pulled in?    Can the antiparticle half of the virtual particle pairs be pulled into the black hole?  Does the black hole lose mass equal to antiparticle mass?

Could someone please provide an explanation for the origin of ? (Ideally someone who I have been speaking with on the h-bar)  Any advanced maths beyond basic calculus will most probably leave me at a loss, though I do not mind a challenge! Please assume little prior knowledge, as over the past few days I have discovered that much of my understanding surrounding the process as virtual particle pairs is completely wrong.


$(2x^2+1)y''-4xy'+4y=0$  $y_1(x) = x$ is given and I have to find $y_2(x)$ and solve equation. thanks.

I need help solving this past exam question, the professor posted exam questions with out solutions to last year's exam, I tried reduction of order, however that seemed to complicate things. And then I tried Euler-Cauchy method however I realized that won't work due to the $(2x^2 + 1)y''$.  Given $y_1=x$ is a solution $$(2x^2 + 1)y'' − 4xy' + 4y = 0$$ Find the second solution $y_2$ for equation.


How do you end up with the formula for ? ($F_s = \mu_s \times N$) or ($F_k = \mu_k \times N$). I know how to use the formula. Now I need to know how to get to it.

The general equation for the force of friction (static or kinetic) is $F_f = \mu * F_N$, where $F_f$ is the force of friction and $\mu$ is the coefficient of friction (its value is dependent upon the surfaces interacting on each other).  Why is it that this equation is so simple and does not contain any other variables that account for the force of friction on an object? Does anyone know how this equation was developed?


Can I directly download audio from a YouTube video instead of first downloading audio+video and then extracting the audio?

Is there a way to search and then download from YouTube, with the situation that I only need to download the audio only, not the video.


I’m writing a series of blog posts and I’m finding a little bit of a conundrum. I want the audience that can be manufactured on Medium but I also want the SEO that comes from long form text on my website.  Is there any type of SEO conflict that would arise from putting the exact same posts on both?

I've heard that Google punishes sites with duplicate content.   If I write an article on my blog then import it on Medium (basically a copy/paste) will Google regard it as a duplicate?   Medium.com is a blog platform (sort of).


This question is different as it tackles the issue of converting a char to an int when adding to an integer array.   The following piece of code, I am trying to implement a string of integers into a int[] array in C#.  My desired output is an array of:  12345678910   This is my code, however, the output of this is not what I desire:  string numbers = "12345678910";  int[] array = new int[numbers.Length];  for (int i = 1; i <= numbers.Length; i++) {     array[i - 1] = numbers[i-1]; }  foreach(var y in array) {     Console.Write(y); }   Output of given code:  4950515253545556574948   Can somebode tell me why I am getting this output, and what I can do to fix this? Thank you!  Edit: Changed my code and it works using this:  for (int i = 0; i < numbers.Length; i++) {      array[i] = int.Parse(numbers[i].ToString()); }

I have a char in c#:  char foo = '2';   Now I want to get the 2 into an int.  I find that Convert.ToInt32 returns the actual decimal value of the char and not the number 2.  The following will work:  int bar = Convert.ToInt32(new string(foo, 1));   int.parse only works on strings as well.    Is there no native function in C# to go from a char to int without making it a string?  I know this is trivial but it just seems odd that there's nothing native to directly make the conversion.


I am new to C++11, and I am trying to build a classic interface / implementation pair. Consider the following sample:  #include <iostream> #include <memory>  // Interface class IFace { public:     virtual ~IFace () = 0; }; // Why must I define this concrete implementation? inline IFace::~IFace () { }  // Implementation class Impl : public IFace { public:     virtual ~Impl () { } };  int main (int argc, char ** argv) {     auto impl = std::shared_ptr<Impl> (new Impl ());     return 0; }   If I comment out the undesirable concrete destructor on the interface inline IFace::~IFace () { }, I get link errors  Undefined symbols for architecture x86_64:   "IFace::~IFace()", referenced from:       Impl::~Impl() in ifac_impl.cpp.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)   I must do this even if the interface and implementation are templated:  // Template IFace2 template <typename T> class IFace2 { public:     virtual ~IFace2 () = 0; }; // I have to do this even if the pair is templated. template <typename T> inline IFace2<T>::~IFace2<T> () { }  template <typename T> class Impl2 : public IFace2<T> { public:     virtual ~Impl2 () { } };  int main (int argc, char ** argv) {     auto impl = std::shared_ptr<Impl> (new Impl ());     auto impl2 = std::shared_ptr<Impl2<double> > (new Impl2<double> ());     return 0; }   Why?   A second question is "am I going about this the wrong way?" That is, is there a better pattern (idiom?) for what I want to do?  I am admittedly trying to fit a conceptual pattern I developed with C# into C++11. Is this sane? If not, what is the sane way?

Is it wrong to write:  class A { public:     virtual ~A() = 0; };   for an abstract base class?  At least that compiles in MSVC... Will it crash at run time?


Is it okay to use app.mycoolname.local for URLs that are private / internal?  We have several applications that are web based, but they are private apps and are not exposed to the public.  We have been using ".net" for some of these, which doesn't make sense since they could collied with a real URL on the internet.  That hasn't been a problem yet.  But now I have a new group of applications and I want to name them using a "popular" name that will definatly collide with a URL on the internet.  Should I use app.mycoolname.local?  I have it set up this way right now, and it seems to be working.  I have read a few places where it was encouraged, but then I saw a few places where it wasn't working (some problem on Mac, but we don't have those, so NBD).

At our office, we have a local area network with a purely internal DNS setup, on which clients all named as whatever.lan.  I also have a VMware environment, and on the virtual-machine-only network, I name the virtual machines whatever.vm.  Currently, this network for the virtual machines isn't reachable from our local area network, but we're setting up a production network to migrate these virtual machines to, which will be reachable from the LAN.  As a result, we're trying to settle on a convention for the domain suffix/TLD we apply to the guests on this new network we're setting up, but we can't come up with a good one, given that .vm, .local and .lan all have existing connotations in our environment.  So, what's the best practice in this situation?  Is there a list of TLDs or domain names somewhere that's safe to use for a purely internal network?


I have a replication of around 200 records in a table, I want to remove all of then except one, how can I do this ??

I'm testing something in Oracle and populated a table with some sample data, but in the process I accidentally loaded duplicate records, so now I can't create a primary key using some of the columns.  How can I delete all duplicate rows and leave only one of them?


Does anyone know how to buy a used car in Ireland as a  non-resident? I am Australian and looking to buy one for the Mongol Rally.  Insurance can be done, but it seems to register the car you need to go in to an office with proof of address. Is that correct? Is there anyway to give an address but we don't have to live there (eg, a friends)?

I am not a resident anywhere and plan to travel for the foreseeable future, mostly in Europe. My country has good visa-free access to most of Europe, so it is conceivable I could remain without any residency for quite some time.  I enjoy driving, and maintaining cars, and I would like to purchase a car somewhere in Europe.  Where, if anywhere, in Europe (or outside of Europe, but with the ability to drive the car in Europe) can I legally purchase and insure a car as a non-resident? I am open to creative solutions like setting up a company to own the car, if the capital and ongoing paperwork requirements for the company are not too onerous.    I am aware that I could save money, get places quicker, etc, by taking trains or flying. I have a passion for cars and driving. Suggesting that I not buy a car is out of scope of this question.


I have a drive that used to have reallocated sectors, until I deleted any data on the affected area and partitioned around it. It works fine, and has worked fine for over a year, I just want to know how I can reset the smart data, as the reallocated sector count has gone back down to 0, I need to reset smart or something so that I can install windows, as windows 7 does not allow installation on "failing" media. Any ideas, or any workarounds are appreciated.

How can I reset the SMART results so it does not register previous results. My reason is that I was testing the hard drives closed together on a closed case. This made one of the HDD fail the Airflow Temperature reading.  After opening the case up (Which lowered the Temp of all drives 10 degrees Celsius in 5 minutes) and then separating the drives a bit more (3 less degrees) All results were good but since the Airflow reading failed in a previous reading, it always shows as failing.  So how can I reset the readings for SMART?


What is the component that is represented with two horizontal lines like a capacitor with three Ground Chassis lines connecting them and a + at the top and a 10μ label.  See picture below (top right corner):

I am looking at  (dual low-voltage power amplifier). On the fourth page, there is a sample circuit; right at the V+ input there is a symbol that looks like a capacitor. However, it looks like it is shaded in. What is that?


Potentially the balance of a lightsaber is very different from that of a sword. With a sword, the weight and momentum of the blade significantly affect the depth of the cut.  When the lightsaber is active, does the weight increase?  Or is swinging it just like swinging the handle?  Perhaps like swinging a Wii controller.

In-universe, a lightsaber is basically a controlled, fixed-length plasma stream that can be used as a sword. As such, the blade wouldn't have any mass (or infinitesimal mass if you want to get technical about E=mc2).  Anyone familiar with fencing or swordplay knows that the weight of the handle and blade, and thus the overall balance of the weapon, is critically important while fighting. A sword that is too blade-heavy is unwieldy; it is difficult to start, stop, and change the path of the blade as it's swung, which is vital to outmaneuvering your opponent in a duel. Conversely, a sword with too light a blade (equivalently, too heavy a hilt) is too easy to swing around. it's hard to "feel" where the blade is, and thus to make the minute changes needed to block a blow or land one. It can also be just as exhausting, in a different way, to wield such a sword; because most of the mass is behind your hand, it takes muscle power to point the blade forward instead of upward, while a balanced weapon would point directly forward from the user's hands. You also get no mechanical advantage while swinging it.  Obviously, out-of-universe the props were full "swords" that were then rotoscoped to paint the beam blade over the white wooden (later plastic) dowel that protruded from the saber. This gives the actual prop used by the actors a more realistic weight and balance, which can be seen in the duels (Darth Maul has to heave a bit to get that double-saber staff moving, and you can see the effort behind a full baseball swing of the sword by Luke or Vader in the original trilogy).  Was there any attempt in-universe to explain the weight and balance that an active lightsaber seemed to possess?


I couldn't help but notice that my NASM Assembly questions didn't have kind of code highlighting. Like this one:   I used Assembly and NASM tags and still didn't work. Do we have Assembly syntax highlighting? Well, not that there is much to highlight in Assembly anyway (although it'd be nice to see my symbols and registers with a different color).

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


This is so simple problem but i don't understand problem. I was click div change class but it does not work when I click on the changing div    $(".one").click(function() { $(this).attr('class', 'two'); });     $(".two").click(function() { $(this).attr('class', 'one'); }); .one {width: 50px; height: 50px; background-color:red;} .two {width: 50px; height: 50px; background-color:blue;}

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


If we are given $20$ people , what is the probability that among the $12$   months there are $4$ months containing exactly two birthdays and $4$ months   containing exactly $3$ birthdays .   I tried , that I even not able to start it .

Given $20$ people, what is the probability that, among the $12$ months   in the year, there are $4$ months containing exactly $2$ birthdays and   $4$ months containing exactly $3$ birthdays?   I am less concerned about knowing the answer than making sure I have thought about the problem correctly.   The general problem seems to be finding the distinct integer-valued vectors that satisfy $$x_1 + x_2 + ... x_{12} = 20\ \ \ \ \ \ \ \ \ x_i \ge 0, i = 1, ..., 12$$  It can be proven that there are $\binom{20+12-1}{12-1}$ such vectors. I am presuming this to be the sample space.  (Please correct me if I'm wrong)  $4\cdot 2 + 4\cdot 3 + 4 \cdot 0= 20$, so there are $3$ distinct groups of $4$ months. Therefore we have $\binom{12}{4\ 4\ 4}$ possible ways to get the desired distribution of months.   The probability I get is $$\frac{\binom{12}{4\ 4\ 4}}{\binom{20+12-1}{12-1}} $$. The answer in the back of the textbook is $1.0604 \times 10^{-3}$ so my answer is off. I just want to know where I went wrong.


I have a WD external hard drive. I've been running the routine tests to make sure all my stuff is safe lately. In Disk Utility, I did Verify Disk on both the disk itself as well as the main partition, which is in the encrypted HD format.  I ran across this error on the partition:     Invalid Disk Label @[number] cksum mismatch   Which didn't seem very good. Resources online have close to no information, and I don't know what this is. It went away after I scanned again, but that is a common occurrence and other posters said that I should keep an eye on it.  I ran Repair Disk and it went without a hitch, but Verify Disk after that still showed the error.  I ran SMART Utility with the SAT-SMART Driver to enable SMART on external USB drives, it passed with 0 bad sectors and stuff.  Any ideas?  MacBook Air - Mavericks 10.9.5

After OSX Update -> Yosemite: No option to login and run the system.  Via Firewire (T) and Diskutils && Diskwarrior: "Unvalid Disk-Label @ 499239710720: cksum mismatch"  Diskwarrior: no option to rebuild Diskutills: Unvalid Disk-Label @ 499239710720: cksum mismatch  What could I do to reboot and rerun the machine? How to fix this problem?


As the title suggests, it's not clear to me the actual difference between a postdoc and research fellow, especially when looking at the typical academia road. I understand that (maybe?) there is a difference between how the two are funded, but which one that (naturally) shows more qualities that can be appreciated when looking for a job as a lecturer? Qualities like 'Independent researcher that can design and lead high quality research programs'. Edit: If it helps, I am talking specifically about the UK system.

Looking at the  on Wikipedia shows that the same academic rank/title can mean quite different things in different countries. For instant, a "research assistant" in the US can stand for an undergrad student doing an internship, while in the UK it can stand for a postdoc. Similarly, the term "lecturer" might stand for a permanent position (e.g. in the UK) or for a teaching assistant position, open to graduate students.   However, when thinking about it, there are not so many kind of possible positions (permanent or not, with teaching or not, with research or not, with PhD supervision or not, with team responsibility or not, etc), and having a clear title could help a lot (for instance, in my case, I've been working in four different countries, with a different job title each time!).    Is there some kind of official taxonomy that one could refer to?  If not, who could be in charge to create it? (the EU, if only for intra-Europe mobility?)


Fiddling around on  deleted question, I accidentally hit the "Reopen" button. Curious, I followed through, and it actually appeared to cast my vote, without screaming at me:  Why doesn't it show the error:  That is shown when a deleted question is voted to be closed?  Can we make it show the error when you hit "reopen", since deleted questions aren't supposed to be voted on?

I've seen .  Voting to undelete will not work because it was deleted by a moderator, but I managed to vote for reopening for some reason.  I doubt this is intentional, perhaps not as important, but still.


Im building a bankAccount program and trying to add my DDs into the global var, but as I create new objects from my constructor function then add them into bankAccount it only shows the last created dd?   What im trying to do is push all DD into bankAccount..  Code is below     // Created my bankAccount with the value of 0 var bankAccount = {};  // Object constructor to created direct debit with name and cost function DirectDebit(name, cost) {   this.name = name;   this.cost = cost; }  // Creating a new DD for my phone var phone = new DirectDebit("Phone ", 20); var car = new DirectDebit("Car ", 250);  function addToBank (dd) {     bankAccount = dd }  addToBank(phone) addToBank(car)  console.log(bankAccount);     this outputs:  DirectDebit { name: 'Car ', cost: 250 }

How do I append an object (such as a string or number) to an array in JavaScript?


We have 100's of elevation contour shapefiles. In each file, only the 10th contour line has values (200, 450, 700, etc..). We have to attribute values for all the intermediate contour lines (2nd line to 9th, 11th to 19th, etc..). While searching for a solution, happened to see this (link below). ArcGIS CalcContour script(as mentioned in the link) will only work in ArcGIS 9.3. So I couldn't even test the script. Please check the "Limitations script CalcContour" note in this link    The script will work like (from what I can see from the YouTube video - link below) we have to snap a point on a contour line and have to draw a line. Finish the editing and enter the increment values. The intermediate lines between the starting and ending point will get the respective values. I've attached a screenshot of that video      Is it possible to do the same or any plugin available for this kind of work in QGIS ?  This is not duplicate of   Our intermediate contour doesn't have any values. And we don't have to interpolate any new contour. We have to just assign the respective values for the contours which are plotted. We know the values for, eg: 200m & 450m contour which will be 1st and 10th line.

I'm mapping a steep mountain range. My main contour interval is 50 m and my intermediate contour interval is 10 m. In steep areas, the interval of 10 m is too small, so I need to leave of the 10 m-interval and use 20 m or 25 m instead.  Is there a way, to do that automated in ,  or ?


This question has been tantalizing me for a day now:     Given integers $a,b,c,d$ such that $d \neq 0$ (mod $5$) and $m$ an integer for which $am^3 + bm^2 +cm+d \equiv 0$ (mod $5$), prove there exists an integer $n$ for which $dn^3+cn^2+bn+a \equiv 0 $ (mod $5$).   My attempt:    It is easy to see that $\gcd(5,m)=1$. We know from Fermat's little theorem that $5 \mid m^4 -1 \Rightarrow 5 \mid (m+1)(m-1)(m^2+1)$. The proof is trivial that $5$ only divides one of these factors. Hence we have $3$ cases:  Case $1 \rightarrow m \equiv 1$ (mod $5$). If this is true then  it follows that $m^2 \equiv 1$ (mod $5$) and $m^3 \equiv 1$ (mod $5$). We can substitute $m$ into the equation and achieve:  $$a+b+c+d \equiv 0 \pmod5$$ $$\Rightarrow d(1)^3+c(1)^2+b(1)+a \equiv 0 \pmod5$$  Where $1$ satisfies the condition.  Case $2 \rightarrow m \equiv -1$ (mod $5$). If this is true then  it follows that $m^2 \equiv 1$ (mod $5$) and $m^3 \equiv -1$ (mod $5$). We can substitute $m$ into the equation and achieve:  $$a-b+c-d \equiv 0 \pmod5$$ $$\Rightarrow d(-1)^3+c(-1)^2+b(-1)+a \equiv 0 \pmod5$$  Where $-1$ satisfies the condition.  Case $3 \rightarrow m^2 \equiv -1$ (mod $5$). If this is true then  it follows that $m \equiv 2$ (mod $5$) and $m^3 \equiv -2$ (mod $5$). We can substitute $m$ into the equation and achieve:  $$2a+b-2c-d \equiv 0 \pmod5$$  From where I am unable to proceed. Can I get a hint?

Let $F$ be a field and let $a \neq 0$ be a zero of the polynomial $a_0 + a_1x + . . . +a_nx^n$ in $F[x]$.  I want to show that $\frac{1}{a}$ is a zero of the polynomial $a_n + a_{n-1}x + . . . + a_0x^n$  How can I do this?


I'm confused about which books I have to read for Elementary number theory for the beginner level. I need references for  very basic books  in Elementary number theory  and that book  must contain given Topics below $ 1.$Divisibility $2.$ congruences $ 3$ .standard arithmetic functions $4.$ Combinatorics permutations and combinations.

I'm in Grade 11. I'm interested in elementary number theory and would like properly study it. I'm not intending to enter any competitions.


Here $x_0$ is a fixed vector and $y_0$ is any linear functional.  (a) The space of all linear transformations $V \to V$ has dimension $n^2$. Consider $I,A,A^2,A^3,.....A^{n^2}$. Then this collection forms a linearly dependent set. So we have a non trivial relation amongst these which will give us a polynomial such that $p(A)=0$.  (b) Don't know how to proceed.

I have come across a question about determining possible minimal polynomials for a rank one linear operator and I am wondering if I am using the correct proof method.  I think that the facts needed to solve this problem come from the section on Nilpotent operators from Hoffman and Kunze's "Linear Algebra".     Question: Let $V$ be a vector space of dimension $n$ over the field $F$ and consider a linear operator $T$ on $V$ such that $\mathrm{rank}(T) = 1$.  List all possible minimal polynomials for $T$.   Sketch of Proof:   If $T$ is nilpotent then the minimal polynomial of $T$ is $x^k$ for some $k\leq n$.  So suppose $T$ is not nilpotent, then we can argue that $T$ is diagonalizable based on the fact that $T$ must have one nonzero eigenvalue otherwise it would be nilpotent (I am leaving details of the proof of diagonalization but it is the observation that the characteristic space of the nonzero eigenvalue is the range of T and has dimension $1$).  Thus the minimal polynomial of $T$ is just a linear term $x-c$.    Did I make a mistake assuming that $T$ can have only one nonzero eigenvalue?  Thanks for your help


how to upgrade my Ubuntu Studio 14.04 to Ubuntu 14.1 or 14.04 without affecting the data and personal files?

What are the different ways I can use to upgrade Ubuntu from one release to another?


Disclaimer: My request is about using the same markdown format used in GitHub for code blocks and syntax highlighting.  In most recent markdown formatters, other than the 4 space indentations, we can create code samples by  before and after the code block, for example:  ``` this would become a code block ```   On the top of my head, I can think of 2 advantages:  Line length  Using backticks instead of the current format would allows us to gain 4 extra characters for each line of code inside the editor. I find this really advantageous as the editor currently allows 79 characters per line and 78 when the scroll bar is showing on the right. This is just around the 80 character limit which most programming languages suggest. Thus giving us back those 4 extra characters would be quite nice in my opinion.  I'm currently using Firefox on Ubuntu, but I don't believe the character count per line would be much different on a different browser/OS, probably 1 extra or less character per line.  Syntax Highlighting and ease of use  Also, I find this style of formatting much simpler for use, especially when explicitly specifying the language for syntax highlighting.   Currently in SE, when we need to specify the language, we need to prepend the code block with the following unindented line <!-- language: js --> followed by empty line. Example:  <!-- language: js -->      // JavaScript code   In contrast, using the triple backticks format, we would use the much simpler:  ```js // JavaScript code ```   In my opinion, the format of the latter is much easier to remember.  P.S. I'm not asking to replace the current format with backticks, I'm asking if we can add this feature thus having 2 ways of formatting code.

Currently, Stack Exchange’s Markdown parser only allows four-space indents to represent code blocks:      // some code     // another line of code    and other Markdown implementations allow for an alternative syntax, that doesn’t require indenting each code line:  ``` // some code // another line of code ```   This is much more convenient to type out. It would be super useful if Stack Exchange could support this syntax.    By extension, this syntax also allow you to specify the source language right after the opening ```:  ```js // some code // another line of code ```   …which would then enable syntax highlighting for that specific language. Although it’s interesting metadata, I don’t think this feature is needed on Stack Overflow, as the syntax highlighting library works pretty well for various languages.  So, even if you would allow this syntax but ignore the ```language, this would greatly improve my productivity on Stack Exchange.  What do you think?  The moderators are currently collecting feedback regarding this feature, so please post a comment with your thoughts. Good idea? Bad idea? Don’t really care? What do you think are the benefits/drawbacks? Experiences? Let them know! Thanks!


I'm reading a csv file which is about 1 GB but it winds up taking over 10 GB of memory. Since DictReader returns an iterator over dicts, each of which has the elements of the header string encoded as keys, I can imagine lines taking up twice as much space (~1 GB) but ten times as much? This confuses me.  import csv  def readeverything(filename):      thefile = open(filename)      reader = csv.DictReader(thefile, delimiter='\t')      lines = []       for datum in reader:          lines.append(datum)      thefile.close()       return lines   The size of the raw string is actually smaller than the size of the parsed dict. I found this out using sys.getsizeof on the first line in the file and on the first record read by csv.DictReader. Therefore, the strict size of the dictionary does not account for the exponential explosion of memory usage when reading the CSV.

I want to know how to get size of objects like a string, integer, etc. in Python.  Related question:   I am using an XML file which contains size fields that specify the size of value. I must parse this XML and do my coding. When I want to change the value of a particular field, I will check the size field of that value. Here I want to compare whether the new value that I'm gong to enter is of the same size as in XML. I need to check the size of new value. In case of a string I can say its the length. But in case of int, float, etc. I am confused.


In bash you can repeat the last command by entering !!, or the third last command !-3 for example.  Is there a quick way to repeat the last 3 commands, without having to type out !-1; !-2; !-3 explicitly?

Suppose I want to execute a sequence of four commands that I have executed before. If the first one is 432 in the command-history, then I could do:  $ !432; !433; !434; !435   I'm curious, is there a more efficient way to accomplish this?


I currently have 16.04, but want to start fresh so that I can clean the hard drive, which is partitioned -- it includes an old version of an MS OS -- that I want to delete.  I created a bootable USB. Even after several reboots of the computer, pressing F12 then Esc, F2, and F10.  The boot menu still does not appear.

How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?


I've been trying to prove the following statement: There is no sequence of continous functions $f_n: [0, 1] \rightarrow \mathbb{R}$ that converges pointwise to the function $f: [0, 1] \rightarrow \mathbb{R} $ defined by $f(x)=0 $ if $x $ is rational and $ f(x)=1$ otherwise. My idea was to assume that such a sequence exists and then prove that, if that's the case, then one of the functions $f_n$ is discontinuous at some point, contradicting our assumption that the functions $f_n$ are all continuous. Here is exactly what I did: Let $(f_n)$ be a sequence of continuous functions $f_n: [0, 1] \rightarrow \mathbb{R}$ that converges pointwise to $f$, which is defined above. Let $\epsilon>0$ be given. We are going to prove that some $f_n$ is discontinuous at $x=1/2$. Since $f_n$ converges pointwise to $f$, there exists $n_0 \in \mathbb{N}$ such that, if $n \geq n_0$, then $|f_n(1/2)-f(1/2)| < 1/2$. Since $1/2$ is rational, $f(1/2)=0$, and we get $|f_n(1/2)| <1/2.$ Moreover, for any $\delta>0,$ there exists some $x_0 \in (1/2-\delta, 1/2+\delta)$ that is irrational. Hence, there exists $n_1 \in \mathbb{N}$ such that, if $n \geq n_1,$ then $|f_n(x_0)-f(x_0)|=|f_n(x_0)-1|<1/4 \implies 3/4<f_n(x_0)<5/4$. Hence, for $N=\max\{n_0, n_1\}$, we get $|f_N(1/2)-f_N(x_0)| \geq |f_N(x_0)|-|f_N(1/2)|>3/4-1/2=1/4.$ My idea was to show that, for $\epsilon=1/4$ and any $\delta>0$, it's possible to find some $x_0 \in (1/2-\delta, 1/2+\delta)$ such that $|f_N(1/2)-f_N(x_0)|\geq 1/4$, for some $N \in \mathbb{N},$ which would imply $f_N$ has a discontinuity at $x=1/2$, giving the contradiction for which we were looking. My "proof", however, isn't right since the $N$ I pick is based on $n_1$, which, in turn, is generally dependant on my choice of $\delta>0.$ With that being said, can anyone help me to prove the statement above?

As a homework question, we got asked the following:     Construct a function $f:[0,1] \rightarrow \mathbb{R}$ which is not the pointwise limit of any sequence of continuous functions   Thinking about it, a function which is nowhere continuous should be sufficient; thus I decided to try to use the indicator function on the rationals, $1_\mathbb{Q}$. Basically, I was just wondering if my proof was alright or not:  Suppose $(f_n)$ is a sequence of continuous functions converging pointwise to $1_\mathbb{Q}$; thus for any $\epsilon > 0$ we have that for all $x$ we can find a $N$ such that if $n \geq N$ then $| f_n(x) - 1_\mathbb{Q} (x) | < \epsilon$. In particular, we have for some $x_1 \in \mathbb{Q}, x_2 \notin \mathbb{Q}$ a $N_1$ and $ N_2$ respectively such that   if $ n \geq N_1$ then $ | f_n(x_1) - 1 | < \epsilon$ if $ n \geq N_2$ then $ | f_n(x_2) | < \epsilon$   Now, as $f_k$ is continuous, for any $\epsilon > 0$ we have that for all $x$ there exists a $\delta > 0$ such that if $ | x- y | < \delta$ then $|f_k(x) - f_k(y) | < \epsilon $. However, if we pick an arbitrary $x \in \mathbb{Q}$, for $n \geq \max\{N_1, N_2\}$, for any $\delta > 0$ we can pick a $ y \notin \mathbb{Q}$ such that $| x- y| < \delta$ yet $ | f_n(x) - f_n(y) - 1|  < 2\epsilon$ (by the triangle inequality and using the pointwise convergence properties); so if we choose $\epsilon = 1/10$, say, then we have by continuity that $|f_n(x) - f_n(y)| < 1/10$, yet $| f_n(x) - f_n(y) - 1|  < 1/5$, which (I believe) is absurd, so we have a contradiction.  I'm a bit iffy about whether this is alright or not (I feel I may be subtly abusing the definitions here), so any feedback would be much appreciated.


I just stumbled upon a  starting with      Hello friendly SO ppl,   I am more or less a CSS noob; and for the life of me, I can't solve this issue. Hopefully this will be easy for one of you awesome people.   and ending with     Thanks a bunch for your help.   While I do not consider this a big issue, I often see phrases like the above which do not really add anything to the question - is it okay to edit them away?    By the way: The above really just was a random example.

I edit a lot of posts every day. I often run across posts with 'Hi' and 'Thanks' on the top and the bottom of the post respectively. I also run across things like:     --User   Should these items be removed during the editing of the post by an editor?


I am little confused about whether I may or not update Adobe Flash plugin for Firefox, on a Fedora 20 machine.  Every time I try to see, let's say a YouTube video, I get a warning message about my Flash plugin being outdated and a potential danger.   My current config is  [root@localhost ~]# yum info  flash-plugin Plugin abilitati:refresh-packagekit Pacchetti installati Nome         : flash-plugin Arch         : i386 Versione     : 11.2.202.400 Rilascio     : release Dimensione   : 18 M Repo         : installed Sommario     : Adobe Flash Player 11.2 URL          : http://www.adobe.com/downloads/ Licenza      : Commercial Descrizione  : Adobe Flash Plugin 11.2.202.400 Fully Supported: Mozilla SeaMonkey 1.0+, Firefox 1.5+, Mozilla 1.7.13+   And Firefox seems to be up to date:  [root@localhost ~]# yum info firefox Plugin abilitati:refresh-packagekit Pacchetti installati Nome         : firefox Arch         : i686 Versione     : 38.0 Rilascio     : 4.fc20 Dimensione   : 115 M Repo         : installed Dal repo     : updates Sommario     : Mozilla Firefox Web browser URL          : http://www.mozilla.org/projects/firefox/ Licenza      : MPLv1.1 or GPLv2+ or LGPLv2+ Descrizione  : Mozilla Firefox è un browser web open-source, creato nel rispetto degl : standard, massimizzando performance e portabilità.   I am not sure what I am doing wrong.

According to my browser (Firefox 34.0) the installed version of the Shockwave Flash plugin appears to be 11.2.202.424. This version is considered to be insecure:       The plugin is therefore blocked:      In the attempt to update the plugin to the version currently considered safe (11.2.202.425), I found out that the recommended version apparantly is already installed:  $ yum info flash-plugin Loaded plugins: langpacks, refresh-packagekit Installed Packages Name        : flash-plugin Arch        : x86_64 Version     : 11.2.202.425 Release     : release Size        : 19 M Repo        : installed From repo   : adobe-linux-x86_64 Summary     : Adobe Flash Player 11.2 URL         : http://www.adobe.com/downloads/ License     : Commercial Description : Adobe Flash Plugin 11.2.202.425             : Fully Supported: Mozilla SeaMonkey 1.0+, Firefox 1.5+, Mozilla             : 1.7.13+   My operating system:  $ cat /etc/redhat-release  Fedora release 20 (Heisenbug)   My questions:   Do I have multiple versions of this plugin installed?  How can I fix my installation?


DLL written in C  extern int32_T myinput; extern int32_T myoutput;  extern void initialize(void); extern void run(void); extern void terminate(void);  void run(void) {     myoutput = myinput * 2; }   Python script  from ctypes import* mydll = cdll.LoadLibrary("C:\\myDLL.dll") mydll.myinput = 10    # Question1 mydll.initialize() mydll.run() print(mydll.myoutput) # Question2 mydll.terminate()   My expectation  20   The actual output  <_FuncPtr object at 0x00000000023646C8>   My Question   How to assign global variable in the DLL? How to retrieve global variable in the DLL?   In short, could you modify my script to make the output be 20?

I'd like to map an int value pbs_errno declared as a global in the library libtorque.so using ctypes.  Currently I can load the library like so:  from ctypes import * libtorque = CDLL("libtorque.so")   and have successfully mapped a bunch of the functions. However, for error checking purposes many of them set the pbs_errno variable so I need access to that as well. However if I try to access it I get:  >>> pytorque.libtorque.pbs_errno <_FuncPtr object at 0x9fc690>   Of course, it's not a function pointer and attempting to call it results in a seg fault.  It's declared as int pbs_errno; in the main header and extern int pbs_errno; in the API header files.  Objdump shows the symbol as:  00000000001294f8 g    DO .bss   0000000000000004  Base        pbs_errno


Fighters have an ability that allows them to take 2 actions in one turn (regular, full, unrestricted actions, unlike those gained from the Haste spell):     Starting at 2nd level, you can push yourself beyond your   normal limits for a moment. On your turn, you can take   one additional action on top of your regular action and a   possible bonus action.   Spells with a casting time of one bonus action have the following restriction:     A spell cast with a bonus action is especially swift. You   must use a bonus action on your turn to cast the spell,   provided that you haven’t already taken a bonus action   this turn. You can’t cast another spell during the same   turn, except for a cantrip with a casting time of 1 action.   Now, this creates some logical conflict. As far as I can tell, RAW would allow you to cast 2 any-level spells and one cantrip as a bonus action (if you have one - only Magic Stone and Shillelagh fall into that category). However, if you were to cast a spell of level 1 or higher as a bonus action, you could not cast any non-cantrip spells with any of your two actions.  This does not make sense at all from a logical point of view (considering "a spell cast with a bonus action is especially swift"). Now while I wouldn't allow casting bonus-action spells with your actions (which is explicitly ruled out - see quote #2), I don't think that the scenario above makes sense.  Are there any passages in the PHB that clarify this issue which I missed? And if there aren't, have there been any developer rulings on this topics?  Addition: If I were to cast a level 1+ spell with a bonus action, could I then use the action granted from Action Surge to cast a non-cantrip spell? RAW, no, but I feel like this ability wasn't taken into account when the rule was created.

Never had an issue with spellcaster scaling until today. A player in the group claims he can cast Eldrich Blast twice on his turn. Once as an action, and a second time as a bonus action since it is a cantrip. Allowing him to shoot 4 beams for a d10 each (he's 5th level so 2 beams per cast). This seems vastly stronger than anyone else's max 2 attacks. After the session which ended early with many players angry this player ruined all encounters, there was much talk of re-rolling into all caster party. One wanting to do the same with a wizards Firebolt spell as a bonus every turn, others still browsing.  So, is it possible for a caster to cast multiple spells in 1 turn? From what I was quoted from the PHB, it's possible to cast any spell as an action, then cast a second spell; as long as the bonus action spell was a cantrip with a cast time of 1 action? So 99% of all cantrips? Please tell me this is wrong, because I feel that if anyone else does this our melee characters will never see a fight again before the casters nuke them down.


Is it possible to start a timer in a Java class, so that I may measure the time it takes for its task?  I tried with  Date d2 = (Date) session.getAttribute("date2"); Date d1 = new Date();  long seconds = (d2.getTime()-d1.getTime())/1000; System.out.println("time: " + seconds);  Date dates = new Date();                 session.setAttribute("date2", dates);   But it's giving me some wierd negative numbers, that I cannot make sense off.

How do I get a method's execution time?   Is there a Timer utility class for things like timing how long a task takes, etc?     Most of the searches on Google return results for timers that schedule threads and tasks, which is not what I want.


First of all my device isn't rooted. I use this device for development purpose: installing apps using ADB, starting activity, and more. What has possibly gone wrong?  When I click on Next button nothing happens. But Cancel button works fine.  (Click image to enlarge)    It's LG G4 International version.

I'm trying to sideload an application, as seen in the picture below.    I have allowed the installation of applications from unknown applied actions in settings, but I can't seem to press the install button. The cancel button works correctly and installing applications via adb install works correctly. What's the problem?  EDIT: For those who have this problem, using ChainFire's  will correct it because the app uses hardware compositing, and Android doesn't notice a "layer" on top of the current screen.


I want to set multiple figures in a horizontal row and I tried subfigure command of subcaption package to do this, referring to the snippet shown at . However, unexpectedly, the result is the figures are located in a vertical column instead of a horizontal row. What is wrong? I'll show a part of my LaTeX code below: my preamble: \documentclass{jsarticle}  \usepackage[dvipdfmx]{graphicx} \usepackage{subcaption} \usepackage{amsmath,amssymb,bm,braket,ascmac}   figure section: \begin{figure}[h!]   \centering   \begin{subfigure}[b]{0.2\linewidth}     \includegraphics[width=\linewidth]{some.jpg}     \caption{coffee}   \end{subfigure}    \begin{subfigure}[b]{0.2\linewidth}     \includegraphics[width=\linewidth]{some.jpg}     \caption{coffee}   \end{subfigure}    \begin{subfigure}[b]{0.2\linewidth}     \includegraphics[width=\linewidth]{some.jpg}     \caption{coffee}   \end{subfigure}      \caption{The same coffees times.}   \label{fig:coffees}  \end{figure}  I'll appreciate for any information. Addition I found I had got a warning below: WARNING The following warnings have been detected. You can output PDF, but please try to fix them. /usr/local/texlive/2019/texmf-dist/tex/latex/caption/caption.sty Package caption Warning: Unknown document class (or package), (caption)                standard defaults will be used. See the caption package documentation for explanation.  main.tex LaTeX Warning: `!h' float specifier changed to `!ht'.  https://texwiki.texjp.org/?LaTeX%20%E3%81%AE%E8%AD%A6%E5%91%8A%E3%83%A1%E3%83%83%E3%82%BB%E3%83%BC%E3%82%B8#g0cf562c

I'm trying to put two jpegs side by side using the subcaption package, but the images are consistently stacking on top of each other rather than side by side. All the solutions I've found simply state that the pictures have to be small enough to actually be side by side but I've tried making them smaller, too small even and they stay stacked. My code looks like this:  \begin{figure}[H] \centering \begin{subfigure}{0.5\textwidth} \centering     \includegraphics[width=0.3\linewidth]{inclusion.jpg}     \caption{inclusions}     \label{fig:inclu} \end{subfigure}  \begin{subfigure}{0.5\textwidth} \centering     \includegraphics[width=0.3\linewidth]{deform}     \caption{grain deformation}     \label{fig:deform} \end{subfigure} \caption{filler text} \label{fig:manmade} \end{figure}   Help would be greatly appreciated.


Should proper nouns be capitalized when used as verbs?  For instance:   "I Googled it" "I googled it"

When a proper noun like "Skype" is used as a verb ("Skyping"), should it be capitalized?  My thinking is that it should be capitalized because the root is a proper noun.  Does anyone know of a rule about this question?


It would be nice if we get this feature on android app where questions with preferred tags are highlighted just like how it is on website.  Website view:    ===========================  Android app view:

It would be nice to show questions based on favorited tags on the Android App, just like the Web application.  The app doesn't handle it right now and this feature would be nice to have.


I have a aaa.service file (controlling the JBoss), that besides other regular stuff contains  [Service] Type=forking ExecStart=/my/script start ExecReload=/my/script restart ExecStop=/my/script stop PIDFile=...   /my/script start creates the PID-file and service aaa status shows it issuing a strange warning:  Supervising process xxx which is not our child. We'll most likely not notice when it exits.   Full output:     Loaded: loaded (/etc/systemd/system/aaa.service; disabled; vendor preset: disabled)    Active: active (running) since Tue 2019-01-22 20:55:16 CET; 34min ago   Process: 32435 ExecStart=/my/script start (code=exited, status=0/SUCCESS)  Main PID: 32542     Tasks: 0 (limit: 512)    CGroup: /system.slice/aaa.service  Jan 22 20:54:56 I011-830 su[32447]: (to aaa) root on none Jan 22 20:54:56 I011-830 su[32447]: pam_unix(su-l:session): session opened for user aaa by (uid=0) Jan 22 20:55:16 I011-830 aaa[32435]: Starting JBoss application server: Starting JBoss application server: Jan 22 20:55:16 I011-830 systemd[1]: aaa.service: Supervising process 32542 which is not our child. We'll most likely not notice when it exits.   Now my actual problem is, that if the process get killed other then by issuing service aaa stop, the systemd doesn't detect it. Even more it claims, that it's running and don't want to start it again:  # cat <pid-file> No such file or directory # service aaa status    Loaded: loaded (/etc/systemd/system/aaa.service; disabled; vendor preset: disabled)    Active: active (running) since Tue 2019-01-22 20:55:16 CET; 40min ago   Process: 32435 ExecStart=/konsens/app/aaa/init/aaastart (code=exited, status=0/SUCCESS)  Main PID: 32542     Tasks: 0 (limit: 512)    CGroup: /system.slice/aaa.service  ... # service aaa start # <--- Instant return, no process started   How can I achieve following goals?   systemd should be able to start and stop my service service aaa status should show the status of the process regardless if it was started by systemd or manually issuing /my/service start systemd should be able to start service after it was killed manually systemd should be able to stop service, that I have started manually

Our application uses an init.d script to start and stop the application as a service. Under CentOS 7, /sbin/init is symlinked to systemd, so I can start my application using either:  service myapp start   or   systemctl start myapp   The issue I am having is that running stop on the service using either service or systemctl will not stop my application. The output of systemctl status:  [root@nec04 ~]# systemctl status myapp myapp.service - SYSV: Service script to start/stop my application    Loaded: loaded (/etc/rc.d/init.d/myapp)    Active: inactive (dead) since Mon 2015-10-05 15:17:41 CEST; 22h ago   Process: 31850 ExecStop=/etc/rc.d/init.d/myapp stop (code=exited, status=0/SUCCESS)   Process: 21054 ExecStart=/etc/rc.d/init.d/myapp start (code=exited, status=0/SUCCESS)   Using the service command:  [root@nec04 ~]# service myapp status Local database at :3307 is started Watchdog is running Application is running   Why does systemctl think my application is not running? Could it be that systemctl is not calling the stop function because it thinks my application is already stopped?


I am new to "Manual Testing". Just wanted to know the difference between Smoke Testing and Sanity Testing with software examples for better understanding.

When there is a new build we perform smoke testing,in few projects they call it as sanity testing. Can someone please elaborate on the difference between the both?


After reading , I am confused by a conflict between two of Magic's rules. At risk of being labelled a duplicate, I want to cover this edge case in more detail than answers to the other questions would, because the other question is very broad. Here's the situation:   can't be countered by spells or abilities.  According to the top answer on the aforementioned question,  can be countered by rule 608.2b if it has no legal targets. This could happen by using  to change the target of Last Word to Redirect.     608.2b [...] The spell or ability is countered if all its targets, for every instance of the word “target,” are now illegal.   I think this is wrong. Last Word can't be countered. The card's text directly conflicts with rule 608.2b. Therefore, rule 101.1 applies.     101.1. Whenever a card's text directly contradicts these rules, the card takes precedence. [...]   By rule 101.1, Last Word has precedence. It seems like it would not be countered by game rules. Instead, I think it would resolve, and rule 101.3 would apply:     101.3. Any part of an instruction that's impossible to perform is ignored.   An illegal target can't be countered, and so that instruction would be ignored. That happens to be all that Last Word does, and so the spell would resolve with no effect. The conclusion I arrived at is not the conclusion arrived at in the answer to the other question. It would make a difference if, for example, the spell had other non-targeting effects that were still possible to perform.  Why does rule 608.2b counter Last Word, and why does rule 101.1 not apply?

I cast , sacrificing my only creature to kill my opponent.  My opponent responds with , which will win the game the other way.  Last Word says "This spell can't be countered."  What else can I do about it besides countering it to prevent my plans from being foiled?  (I'd really like to have the last word here.)    Historic Note: before of the April 2018 rules change, uncounterable spells with targets used to actually have different wording (still visible on the printed cards) implying that they still could be countered.  For example, Last Word said:     Last Word can't be countered by spells or abilities.   Meanwhile Akroma, Angel of Fury said:     Akroma, Angel of Fury can't be countered.


What I had already performed are:  sudo /etc/init.d/mysql stop /usr/sbin/mysqld --skip-grant-tables --skip-networking &    After this I am getting:  [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release.   Please use the full name instead.  150929 11:48:31[Note] /usr/sbin/mysqld (mysqld ....)starting as process 3633 ...   And its not processed further.  What to do?

I've set up mysql and phpmyadmin and chose not to set a password when installing hoping that once set up i could login with root and no password but i get the following error from phpmyadmin:  Login without a password is forbidden by configuration (see AllowNoPassword)   I have previously moved the phpmyadmin folder to /var/www/   I have tried changing the following line  $cfg['Servers'][$i]['AllowNoPassword'] = false;   to  $cfg['Servers'][$i]['AllowNoPassword'] = true;   but still had no success, so i am wondering is there a way i can change the root passwords for both so i can access phpmyadmin and create databases.


I was always wondering how a hard drive finds the first bit of data.  When a hard drive spins up, whatever it reads must be a circular stream of data until the reading head moves to a different position.  But in such a circular stream, how does the drive know where the first bit and the last bit lie, so that it can pass on the data in the right order?

I heard that to read or write data on a hard disk drive, we need the cylinder id and the sector  id. First move the hdd's r/w heads to the cylinder specified by the cylinder id, and then to the sector specified by the sector id. Is it correct?  Do we need the platter id, and which of the two surfaces of the platter? Or equivalently, the track id (since we have the cylinder id)?  Thanks.


I have a Problem with my BibTex Settings. When printing I want first name before surname. Right not it is the other way around.  Also, if I have multiple authors, the first one is displayed surname, first name and every following author is displayed first name surname (without comma).  I think that this is very bad styling because it should be the same for all authors. Here I have some of my configurations for you:  \usepackage[     backend=bibtex,     bibwarn=true,     bibencoding=utf8,     sortlocale=de_DE,     style=authoryear,     backref=true ]{biblatex}  \setlength{\bibitemsep}{\baselineskip}   And my BibTex:  @book{Dean.2004,     title={MapReduce: Simplified Data Processing on Large Clusters},     author={Dean, Jeffrey and Ghemawat, Sanjay},     year={2004},     url={http://research.google.com/archive/mapreduce.html},     publisher={Sixth Symposium on Operating System Design and Implementation} }   And last how it is displayed right now

With biblatex and verbose-trad2 style, I would like to reverse the order of the last name and the first name for inline references.  The default behavior is:     John DOE, Title, place : publisher, year   for inline references (in my case, in a footnote with footcite command) and:     DOE, John, Title, place : publisher, year   in the bibliography at the end of the document.  I would like to have both inline and final references in the following format (similar to the bibiography style).      DOE, John, Title, place : publisher, year   P-S : There are some close questions (like ) but only about the final bibliography (and no inline references). \DeclareNameAlias{sortname}{last-first} works only for the ending references (not inline ones).


Not a boost straight up to escape velocity, just sufficient added momentum to make a significant economic saving on fuel cost, mass and complexity of a standard launch. It seems ludicrous to me how much fuel in a standard launch appears to be wasted pushing thousands of tonnes of rocket fuel in a vertical direction from a standing start.  The system I envisage would have a horizontal track of possibly 2-3km (distance to be debated), acceleration via external systems (electromag or JATO?), continue up a ramp of slowly increasing gradient, with craft's own engines now running, and exit the ramp at between Mach 1 or 2. Safety run-off track if craft's own engines fail to ignite properly. Winged style craft for stability from ramp & shuttle-style landing.  Similar I know to the Phys.SE  question here, but acceleration could be more survivable. Had a longer script but it appeared to over-run the site limit. Acknowledge AdamRedwine's railgun question -would have added my contribution to that but my Reputation today is only 1.  Acknowledge Gerry Anderson's Fireball XL5 puppet show on British TV in the '60s - the launch concept has always stayed with me! Submitted for criticism.

Basic facts: The  is 2.4 miles deep.  Railguns  of a projectile on the order of 7.5 km/s.  The Earth's  is 11.2 km/s.  It seems to me that a railgun style launch device built into a deep shaft such as an abandoned mine could reasonably launch a vehicle into space.  I have not run the calculations and I wouldn't doubt that there might be issues with high G's that limit the potential for astronauts on such a vehicle, but even still it seems like it would be cheaper to build such a launch device and place a powerplant nearby to run it than it is to build and fuel single-use rockets.  So, what is the possibility of a railgun assisted orbital launch?   What am I missing here?  Why hasn't this concept received more attention?


My 32 bit PC has been running on Ubuntu 14.04, which is no longer supported. The subsequent Ubuntu releases are for 64 bit machines. I am therefore concerned to know about two things:  What exactly are the hazards of continuing with an unsupported OS like Ubuntu 14.04? If it is not advisable to continue with it, what other distributions can work for me and run my presently installed apps?

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


I have two columns on Microsoft Excel:  F is the column with the date service ended; E is the column with the date service began.    How do I calculate and report the number of months served for each person?

So I am trying to find a formula for excel. Bascically I have two dates and I need to know the number of months between them. But to add complexity, I need a rule in there that if the earlier date is the 1st to 15th it will be a whole month but if it is 16th to end of the month it will be a half month.  For example: Date 1: April 4, 2012 Date 2: December 31, 2012 Answer: Number of months would be 9 months  If Date 1 was April 16, 2012, with the same Date 2 of December 31, 2012, then the number of months would equal 8.5.  Can anyone help me with this one? You help would be greatly appreciated. many thanks


I have a on-off switch that'll use for a kill switch for my car using the gas pump. The switch says 6A/125V 3A/250V 22 AWG. For my purpose it needs to handle 12V 20 Amps max.

I'm looking for a high current DC switch (able to switch something like 5V@30A) and I've encountered several DPDT that might do what I need, however they are only rated for AC applications (3A@250VAC or 6A@125VAC). Are these rating convertible to DC? or is that something that only the facturarer would know?


Let T be a linear transformation from a vector space V over reals into V such that $T-T^2=I$. Show that T is invertible  Solution: I started by multiplying T on both sides and getting   $-T^3=I$

Let $T$ be a linear transformation from a vector space $V$  over reals into $V$ such that $T-T^2=I$. Show that $T$ is invertible


I'm using MikTex. However, it's quite annoying to me that I have to compile the scripts manually. Is there any software which compiles the scripts automatically. By this I mean the automatic compilation on Stack Exchange.

Possible Duplicate:          I'm looking for an application in which I can write pure LaTeX in one half of the screen and on the other half to see the compiled document in real time. This seems really like an obvious way to do LaTeX authoring but it doesn't look like any software is able to do it. LyX is not what I'm looking for. I want to edit the actual LaTeX and see it rendered in real time. Why isn't this already being done somewhere?


I have a List of anonymous types List<'a>, a' is new {OptionSetValue servingTime, OptionSetValue servingGroup, string servingClass, string desc, string childName, Guid childId, EntityReference item, OptionSetValue type, Guid sensitivity}  I have constructed such a list inside a foreach statement and need to add the list to another list of the same type from outside the for loop (groupedAllergies). Obviously what I wrote would not work as object does not contain a definition for the anonymous types I am trying to access. How can I remedy this?!      var groupedAllergies = new List<object>(); <--- problem      foreach (var line in items)     {         OptionSetValue servingTime = line.servingTime;         OptionSetValue servingGroup = line.servingGroup;         string servingClass = line.servingClass;         string desc = line.desc;         string childName = line.childName;         Guid childId = line.childId;         Guid sensitivity = line.sensitivity;            var queryAllergyItems = groupAllergies.Where(e => e.servingClass == servingClass                                                           && e.servingTime == servingTime                                                           && e.servingGroup == servingGroup                                                           && e.desc == desc                                                           && e.allergies.Intersect(allergies).Any()).Select(r => new                                                           {                                                               r.item,                                                               r.type,                                                               r.allergies                                                           }).ToList();           var items = queryAllergyItems.Select(r => new          {              servingTime,              servingGroup,              servingClass,              desc,              childName,              childId,              r.item,              r.type,              sensitivity = r.allergies.Intersect(allergies).First()             }).ToList();            items.ForEach(e => groupedAllergies.Add(e));      }         foreach(var allergy in groupedAllergies)      {           var servingTime = allergy.servingTime;             //object doesn't have definition for servingTime!!       }   Is this a valid solution?!  var o = new { servingTime = new OptionSetValue(), servingGroup = new OptionSetValue(), servingClass = "", desc = "", childName = "", childId = new Guid(), item = new EntityReference(), type = new OptionSetValue(), sensitivity = new Guid() };  var groupedAllergies = new[] { o }.ToList(); groupedAllergies.Clear();

In C# 3.0 you can create anonymous class with the following syntax  var o = new { Id = 1, Name = "Foo" };   Is there a way to add these anonymous class to a generic list?  Example:  var o = new { Id = 1, Name = "Foo" }; var o1 = new { Id = 2, Name = "Bar" };  List<var> list = new List<var>(); list.Add(o); list.Add(o1);   Another Example:  List<var> list = new List<var>();  while (....) {     ....     list.Add(new {Id = x, Name = y});     .... }


I wrote:     We implemented the proposed system as a visual tool. It is a Windows application using an embedded web browser to render the web page to provide the user with the visual identification of the page elements.    Here, I used the pattern "use A .... to do X"; however, I used two "to do", is it a correct usage of this pattern? I mean if I can add extra "to do" as complements of "use" or not? (My question is not about repeating of "to", I don't care it here)

I often don't know whether I should repeat the "to". E.g.:     To enable the car to perform jumps between blocks or simply to go   faster, accelerator blocks can be placed, which as the name   indicates increase the car's speed.   vs.     To enable the car to perform jumps between blocks or simply go faster, accelerator blocks can be placed, which as the name indicates increase the car's speed.   Is there any general rule to decide between those two options?


I have a laptop supports 64bit. I'm using Ubuntu 12.04 32 bit by a mistake I installed 32bit. Now I want to switch from 32 bit to 64 bit and a new version of Ubuntu 12.10 is also available so I want to install it.   Is there any easy way with out New Installation ?  I have a separate partition for Ubuntu of 40 Gb size if I reinstall the new 64 bit version on it will it remove my applications and other stuff from the other partitions. Like /home partition and /data partition.  Also tell how to make backup.

As per title, I wish to know if I can, after a successful 32bit setup and consequent software installations, update to a 64bit version.  I know how to partition (actually one of the solutions is to set /, /etc, /home, /var/www, and /opt as separate partitions) and I know that a clean install is way better than a dirty one, yet I would like to know if/how it's possible to do that.