How did Einstein come the conclusion that nothing can travel faster than the light in vacuum?

As a lowly physics undergrad who has been chewing on this 2nd postulate of special relativity for a year or more, I simply can't wrap my head around reasons why it is true or how Einstein might have been convinced enough to propose this postulate.  Consider Alfred who is riding in a car travelling at 88 m/s with his headlights on and Bernard who is on the side of the road hitch hiking. Why does the light propagating from Alfred's car move at $c$ relative to both Alfred and Bernard, and not at $c$ + 88 m/s relative to Bernard?   The nifty results of special relativity all kind of hinge on this idea, and asking my professors in class hasnt really yielded an answer much more than "because we have never observed a case otherwise".


My Tourist Schengen VISA application was rejected for 1st time on 16-Apr-2015 with reason as “Your intention to leave the territory of the Member States before the expiry of the Visa could not be ascertained”.  Based on rejected reason stated, I had re-applied for Tourist Schengen VISA on 23-Apr-2015. The covering letter in my application I have clearly mentioned:   My purpose of visit (which is Sightseeing and Tourist purpose) My obligations because of which I need to return back to INDIA after my tour,   My Itinerary with every single details of my Hotel Booking, Travel Bookings with address and Telephone numbers & confirmations for the same and My willingness to visit Embassy office if they needed to interview me or need to speak to me   However my Tourist Schengen VISA application was again rejected for 2nd time on 24-Apr-2015 with a new reason as “Justification for the purpose and conditions of the intended stay was not provided”.  I am really not clear as to what exact information or Justification are they looking for, which I may have not provided in my previous applications.  My friend with whom I have planned this tourist trip was granted VISA when he submitted same documentations (because we planned to travel in same trains and flights and stay in same hotels during our trip) with similar covering letter. However my application was rejected twice.  Can someone please help me what should I be doing?   Reapply again with Italy Embassy  Appeal to Tribunale Amministrativo Regionale (T.A.R.) (regional administrative court) of Lazio. Any contacts how I can get this done and what could be the time and fees? Should I apply from any other county? I am visiting France, Switzerland, Germany and Italy My passport is being stamped every time by Embassy with Date and VISA TYPE on it.    Will this be problem in future?

I am Sri-Lankan staying in Bangladesh working in well established company in Bangladesh. I, my wife and two kids applied for Schengen visa from German embassy in Dhaka. I got only sponser letter from my paternal uncle in Germany. We submit all company letter, bank account, school letters, insurance, booking air tickets, etc.  Our visa refused and the reason given "your intention to leave the territory of the member states before the expiry of the visa could not be ascertained" so I want to know what it mean. And how I apply again fix by this reason? Our annual vacation starts on 15 July for one month. I applied visa for 15 days. We plan to stay 15 days in Germany and travel to Sri Lanka and back to Bangladesh.


I'm fine if you just give me the NBT or something but I'm on an anarchy realm and need to give my friend a pick to break bedrock since he's on console and can't download exploits.

So i'm trying to do different kinds of pickaxes and axes, and I don't now a way to change the blocks that a pickaxe can break. Like how do i to make a diamond pickaxe break bedrock. if possible teach how to do it on 1.16.1. I found that command... /give @s minecraft:diamond_pickaxe 1 0 {"minecraft:can_destroy":{"blocks":["bedrock"]}} ...But it isn't for 1.16.1


I'm trying to programatically call Home button with another button inside my project. App compiles fine, but when I tap the button that should call Home I receive following error:     Attempt to invoke virtual method 'void   android.content.Context.startActivity(android.content.Intent)' on a   null object reference   Here is my code (just essentials):  import android.app.Activity; import android.content.Intent;  import android.content.Context;  public class ClassName extends ReactContextBaseJavaModule {   private Context context;    @ReactMethod   public void minApp() {     Intent startMain = new Intent(Intent.ACTION_MAIN);     startMain.addCategory(Intent.CATEGORY_HOME);     startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);     context.startActivity(startMain);   } }   What am I doing wrong?  SOLUTION:  Due to the fact that my app uses react native, the code in bridged method in java file should look as below:  import android.content.Intent;  import android.content.Context;  public class ClassName extends ReactContextBaseJavaModule {    @ReactMethod   public void minApp() {     Context context = getReactApplicationContext();     Intent startMain = new Intent(Intent.ACTION_MAIN);     startMain.addCategory(Intent.CATEGORY_HOME);     startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);     context.startActivity(startMain);   } }   Using this we can assign Home button function anywhere we want ;)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Let $f$ be positive and continuous on $[0,1]$. Find $\lim_{p \to 0} ( \int_{0}^{1} f(x)^p dx)^{1/p}$ My approach: $f$ is continuous on $[0,1] \implies$ $\exists \min_{x\in[0,1]}{f(x)}$ (call it $m$) and $\max_{x\in[0,1]}f(x)$ (call it $M$). so we have $0<m\leq f(x) \leq M$ for all $x\in[0,1]$ therefore $m\leq (\int_{0}^{1} f(x)^p dx)^{1/p} \leq M$ so by Intermediate value theorem, $\exists c\in[0,1]$ such that $f(c) = (\int_{0}^{1} f(x)^p dx)^{1/p}$ Then $\lim_{p \to 0} (\int_{0}^{1} f(x)^p dx)^{1/p} = \lim_{p\to 0} f(c)$ Can't proceed further

I'm given that $f \in L^1$ and $f(x) \neq 0$ a.e. and trying to prove that for q > 0  $$\lim_{q \to 0} (\int_0^1 |f|^q)^{1/q} = e^{\int_0^1 \ln|f|}$$  My work:  I took the log of both sides to reduce the problem to  $$\lim_{q \to 0} \frac{1}{q} \ln(\int_0^1 |f|^q) = \int_0^1 \ln|f|$$  Since $\ln$ is a concave function I used Jensen's inequality to show that  $$\frac{1}{q} \ln(\int_0^1 |f|^q) \geqslant \int_0^1 \frac{1}{q}\ln|f|^q = \int_0^1 \ln|f| $$  So if the limit exists, I know  $$\lim_{q \to 0} \frac{1}{q} \ln(\int_0^1 |f|^q) \geqslant \int_0^1 \ln|f|$$  Now I can't make any more progress to reverse the inequality.  Maybe I need a completely different approach.  Also what about the necessity of $f \in L^q$? Please help.


I'm aware that actual focal length of a lens on APS-C cameras is longer than what is written on the lens.   My question is, for lenses that are specially designed for APS-C cameras (like a Nikkor DX lens), do they write actual focal length on the lens or it is the focal length if mounted on a full-frame camera?

So, I mount a 200mm lens on my Canon 450D. It effectively becomes a 320mm lens. Is this the equivalent of 320mm on a full frame camera? That is, from what I've figured out I get an equivalent field of view but nothing I've read is indicating that I get the magnification to go along with it.  So as my question says in the title, does my crop sensor camera really turn my lens into a longer one (in terms of magnification), or does it just look like it based on the reduced field of view I get?


Here's my question: if atoms have well defined energy levels and those differences correspond to the frequencies of light that can be absorbed, how is it that opaque objects absorb all or most visible light frequencies?, frequencies get absorbed and you basically don't have any visible light coming out on the other end.   Shouldn't only those frequencies that have to do with its energy levels get absorbed? Yes, I realize ordinary materials have many different compounds, but surely they don't add up to an infinite number of energy levels? Thanks.

I think I understand how a solid can appear transparent as long as the energy of the photons travelling through it are not absorbed in the material's bandgap. But how does this band gap relate to conduction and valence bands which explain insulators, semconductors, and conductors as described in the 'band theory for solids' (say) here:  ?  Specifically I wish to use answers to this question to construct a useful visualisation of this aspect - trying to explain to lay people why some solids are transparent and some are semiconductors (or both) and using the bandgap to do so. See a basic, perhaps rushed, explanation of transparency started here:   There are two good reference questions here:  and followup here:   So of course its not just about bandgap but also how classical waves are built up from a quantum substrate and materials with structures smaller than the wavelength of light. That's my visualisation challenge...  I intend to show:   high energy X-rays make many solids appear to be transparent because they are not absorbed vs the energies in IR, visible, and UV light for some materials. photons vs electrons being fired into a material glass structure vs crystal lattics or random structure solids opaque thin carbon vs transparent thick diamond and glass - why is paper opaque at visible light frequencies QED to classical wave showing how one leads to the other and how each model explains transparency Conduction, semiconduction, insulation and bandgaps and their relation to visible light energy transparency and probably some other aspects.   To reiterate my question: How does the bandgap theory of solids link transparency to conduction and valence bands (or other bands) ?  Feel free to suggest mechanisms for visualisation or any other contributing factors to explain this property of QED.


I dynamically create a checkbox that has an . Unfortunately the EventListener doesn't work if I change the text of the checkbox-label with innerHTML:      let label = document.createElement('label'),     input = document.createElement('input'); input.setAttribute('type', 'checkbox'); input.addEventListener('change', () => alert('Change Detected'));  label.appendChild(input); document.body.appendChild(label); label.innerHTML += 'Select Me!';     How can I circumvent this problem and why does it even exist?  Here a working snippet without the innerHTML:   let label = document.createElement('label'),     input = document.createElement('input'); input.setAttribute('type', 'checkbox'); input.addEventListener('change', () => alert('Change Detected'));  label.appendChild(input); document.body.appendChild(label);

In the following example code, I attach an onclick event handler to the span containing the text "foo". The handler is an anonymous function that pops up an alert().  However, if I assign to the parent node's innerHTML, this onclick event handler gets destroyed - clicking "foo" fails to pop up the alert box.  Is this fixable?
      foo


I’m a Filipino passport holder. No U.S. visa, no Canadian visa. I’m flying from Costa Rica to Mexico City. Then Mexico City to Vancouver, then to China, then Philippines.  I get on China Southern flight number 378 in Mexico City and it lands in Vancouver Terminal M.   The exact same flight number on China Southern 378 and Terminal M and even the same seat goes all the way from Vancouver to Guangzhou.   The stop in Vancouver is 1 hour 50 minutes. We have to get off the plane.  The Canadian website on in transit immigration is very unclear.   It says if you stopover on an international flight you will “stay in the sterile transit area” while you transition in the same flight like I will.    I take this to mean we get off the plane, stand around in the “sterile transit area” for no more than 1 hour 50 minutes and then we get back on the plane.  No special visa would be required, is this correct?  Has anyone done this?

I'm passing through Canada, on my way to somewhere else. I'm staying only a short time.   Is there a website, or some other way of find out out if I need a visa?


How to give space in between two blocks in a responsive single page website in drupal 7? Example: we created two blocks about us and ethics in one row through drupal admin .We want to give vertical space between these two blocks!!

While trying to convert a HTML responsive theme to Drupal 7 theme, it's responsive is not working!!!  Can anyone help me with this to sort the issue? We have copied Bartik theme and removed the CSS and pasted the HTML5 theme CSS and JS that we created. changed the index.tpl into page --front.tpl.php and copied it into the template folder. In the page-- front.tpl.php we give all the path for CSS and JS as:    <?php $path="http://".$_SERVER['HTTP_HOST']; ?> <link rel="icon" href="$path."> <link rel="shortcut icon" href="images/favicon.ico" /> <link rel="stylesheet" href="<?php echo $path.base_path().path_to_theme()?>/css/style.css">.    "As specified we gave path for all CSS and JS files, but don't know where we went wrong!!"


I have a Ubuntu 16.04 LTS & Win 10 dual boot desktop PC .  I want to be able to send a mail to 1 or many accounts (mainly gmail.com) from this Linux using the console .  The command has to be intuitive and  sort of a "template", something like  mail receivers -s "this is the subject " " this is the message" ...   Something simple. How can I achieve that?


Is one DNA molecule = one chromosome or is one DNA molecule = all the chromosomes, ie, all the genetic material in our cells? I have googled it but  I am not getting clear answers ?

Do the 46 human chromosomes form a single unbroken DNA helix?  Or is it rather that a human's genome consists of 46 disconnected helices?    If it is the former, does the common numbering scheme for the chromosomes have any correlation to their actual ordering in the one large strand?  If is the latter, is there a convention on how the chromosomes are ordered in genomic datasets?  Also, is there a clear understanding of how sister chromosomes "find" each other in Meiosis I?  Generally, during periods when Mitosis/Meiosis are not occurring,  what's a good physical picture for how the chromosomes are physically arranged (e.g. a bowl of 46 spaghetti noodles, or maybe the sister chromosomes always stay close together, etc)  thanks!


Is there any way to have multiple text formats in a single qgis label?  I am making a map that shows mountain summits.  Many of these summits have more than one name and I would like to show each name in a label and have each name rendered with different formatting to show what type the name is.  For example, summits, in the US, often have an "official" name from the GNIS database, a name as shown on a 1:24000 USGS topo map (often just the elevation of the summit), and a local nickname.  I would like to be able to have a label that renders each name in a different type font and/or font size.

I would like to place the elevation-number of a point in a different front size and centred under its name:    Is that possible?  (That is my actual labeling: label || '\n' || elevation)


Ordinary matter acts to slow down the expansion of the universe. That makes intuitive sense, because the matter is exerting a gravitational force, acting to pull things together.  Moreover,  has “negative pressure” and negative pressure corresponds to a pull. Then why are galaxies being pushed apart?

I was wondering how dark energy is effecting the rate at which the universes expansion occurs.


How do I download all of my questions and answers across all of the sites in the network?   And is there a way that could preserve special LaTeX formatting?

Is there a way to quickly save all my Stack Exchange content across all Stack Exchange sites, as hundreds of HTML pages? (for me probably 15 or 20 sites: SO, dsp.SE, unix.SE, etc.)?  The ideal way would be one .HTML file for each question that I asked / answered / commented? What would be the ideal tool for that?    Remark: I've already read interesting questions like  but it doesn't exactly answer my concern here.


Hi please I want clarification on the question when U.K. Visa forms ask "Do you have savings ". Is it the same as the bank statement you submit. The enquiry I am making has to do with the filling of the forms.Thanks

The UK Visas and Immigration Directorate publishes  that provides helpful tips that can result in successful visa applications. Section 2 of this guidance opens is entitled "other documents you may want to provide" (emphasis mine).  Section 2: other documents you may want to provide – all visitors This section provides guidance on the types of documents that you may want to provide to help us consider your application against the Immigration Rules. Previous travel documents/passports, which show previous travel. Financial documents showing that you have sufficient funds available.  These must clearly show that you have access to the funds, such as:  bank statements building society book proof of earnings such as a letter from employer confirming employment details (start date of employment, salary, role, company contact details) where a third party (who is either in the UK or will be legally in the UK at the time of your visit) is providing financial support to you e.g. a business, a friend or a relative, documents to show that they have sufficient resources to support you in addition to themselves and any dependant family should be provided   The first item is "bank statements" and this ties in with the , which says...  evidence that you can support yourself during your trip, eg bank statements or payslips from the last 6 months  (Note 'eg' is a Latin abbreviation meaning "for example"; this appears to be optional rather than a fixed requirement.) Question: How should someone interpret this such that the chances of success are maximized? How many statements should I submit? What are they looking for and what do my bank statements tell about me?


I'm having problems with making realistic texture. Following Blender Guru tutorial from a year ago I made a plane with custom material using nodes and few images from CrazyBump.   For some reason internal material preview shows my material exactly how I want it, but render is different (both full render [F12] and render preview). There is some data "getting trough" because the plane have a different colour but that's it.   I tried manipulating the nodes, subdividing a plane but nothing seems to work.  Is that just a wrong workflow, or maybe a bug? Am I missing something?  Would appreciate any help. :)  here's a file:

Because I am pretty new to blender I watched the tutorial  from BlenderCookie.com.  I loaded  onto a sphere but then in all views the texture is just some kind of blurry with no details.


I try to develop Bayesian estimation for one dimensional Gaussian with unknown $\mu$ and known $\sigma$. I got  \begin{align} p(x|D) &= \int p(x|\mu)p(\mu|D) d\mu  \\        &=\int \frac{1}{\sigma \sqrt{2\pi}}\exp\left(-\frac{1}{2}\left(\frac{x-\mu}{\sigma}\right)^2\right)\frac{1}{\sigma_n\sqrt{2\pi}}\exp\left(-\frac{1}{2}\left(\frac{\mu-\mu_n}{\sigma_n}\right)^2\right)d\mu  \\        &= \frac{1}{2\pi\sigma\sigma_n}\exp\left(-\frac{1}{2}\frac{\left(x-\mu_n\right)^2}{\sigma^2+\sigma_n^2}\right)f(\sigma,\sigma_n)  \\        &\text{ where }  \\ f(\sigma,\sigma_n) &= \int \exp\left(-\frac{1}{2}\frac{\sigma^2+\sigma_n^2}{\sigma^2\sigma_n^2}\left(\mu-\frac{\sigma_n^2x+\sigma^2\mu_n}{\sigma^2+\sigma_n^2}\right)^2\right)d\mu \end{align}  Now, It says that $p(x|D)$ is proportional to  $$\exp\left(-\frac{1}{2}\frac{\left(x-\mu_n\right)^2}{\sigma^2+\sigma_n^2}\right)$$  as a function of x and hence $p(x|D)$ is normally distributed with mean $\mu_n$ and variance $\sigma^2+\sigma_n^2$.  I am asking for an explanation and/or proof for why $p(x|D)$ is proportional to the $\exp$ term $\Rightarrow p(x|D)$ distibuted normally.  Edit: this answer I got is general. I am asking for an explanation for this case.

Here's an  from one of the questions in the newsletter.  I'm not trying to suggest that it's incorrect, I just don't understand why it's an acceptable practice.  I know that simplifying assumptions are made all the time, but why is this useful?  \begin{equation} \begin{split} p(\theta|y) &= \frac{p(y|\theta)p(\theta)}{p(y)} \\ &\propto\frac{\Gamma(\alpha)\Gamma(\beta)}{\Gamma(\alpha+\beta)}\theta^{\alpha-1}(1-\theta)^{\beta-1}*\binom{n}{y}\theta^y(1-\theta)^{n-y} \\ &\propto\theta^{\alpha-1}(1-\theta)^{\beta-1}*\theta^y(1-\theta)^{n-y} \\ &\propto\theta^{\alpha+y-1}(1-\theta)^{\beta+n-y-1} \\ &=\frac{\Gamma(\alpha+y-1)\Gamma(\beta+n-y-1)}{\Gamma(\alpha+\beta+n-1)}\theta^{\alpha+y-1}(1-\theta)^{\beta+n-y-1} \end{split} \end{equation}  My issue is that we go from "proportional-to" to "equals", which is fine, but what exactly is this saying?  As in, I understand how we go from each line to the line following it, but I don't understand what this tells us.  Sure, we eventually get back to a Beta distribution, but only after removing a ton of values.  Are these values not important?  Does it mean anything profound that a Beta prior with a binomial likelihood has the property of conjugacy?  It can make calculations simpler, sure, but is this useful in practice, if so why?      EDIT 1: So are these constants actually thrown out, or accounted for later? I understand that constants don't matter with respect to proportionality and integration, but throwing them out completely just seems counter-intuitive to me. Sure, if you're multiplying/dividing a bunch of numbers by an expression with a constant, and all you care about is the relationship of those numbers to each other, then you can throw out constants and the relationship remains the same. Is that what's going on here?  EDIT 2: From what I can tell, we get rid of constants, simplify, and then take the integral and normalize that integral. By virtue of the normalization, we're inherently accounting for the constants that we removed before. Is this correct? I think I understand now, for whatever reason, I kept thinking of the original equation as a scalar value rather than a probability distribution.


How can I remove the space between margin and align environment    \documentclass[a4paper,14pt]{article} \author{} \usepackage[fleqn]{amsmath} \usepackage[a4paper,margin=1in,left=2cm,right=1cm,top=1.5cm, bottom=1.5cm]{geometry}  \renewcommand{\baselinestretch}{1.5} \AtBeginDocument{% \setlength{\abovedisplayskip}{0pt}% \setlength{\belowdisplayskip}{0pt}% \setlength{\abovedisplayshortskip}{0pt}% \setlength{\belowdisplayshortskip}{0pt}% } \date{} \title{}  \begin{document} \maketitle normal text \begin{align*} \frac{1}{2}+\frac{2}{3}=\\ \frac{3}{6}+\frac{4}{6}= \frac{7}{6}\\ \end{align*} \end{document}

I'm using the following code. What should I do if I don't want the fixed indent from the left margin of my page?   \documentclass[fleqn,oneside]{article} \usepackage{amsmath} .... \begin{align} a_1& =b_1+c_1\\ a_2& =b_2+c_2-d_2+e_2 \end{align}


I have a problem, I have a button that is in a layout without activity (without class), the layout is called item_list_products. That button is there, but I want to use the .setOnClickListener event in my HomeFragment. Is there a way to solve that? since that is why it gives me the error.  Mi codigo: HomeFragment.class         public class HomeFragment extends Fragment {           private HomeViewModel homeViewModel;           Button bttn_comprar;           public View onCreateView(@NonNull LayoutInflater inflater,                              ViewGroup container, Bundle savedInstanceState) {           homeViewModel =                 ViewModelProviders.of(this).get(HomeViewModel.class);           View root = inflater.inflate(R.layout.fragment_home, container, false);           bttn_comprar = (Button) root.findViewById(R.id.comprarBttn);            //This is where I get the error, since the button is in a different layout.           bttn_comprar.setOnClickListener(new View.OnClickListener() {                      @Override                      public void onClick(View view) {                       }           });         }  Mi codigo de layout: item_list_productos      <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical" android:layout_width="match_parent"     android:layout_height="match_parent">        <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="horizontal">          <ImageView             android:id="@+id/idImagen"             android:layout_width="wrap_content"             android:src="@mipmap/ic_launcher"             android:layout_height="wrap_content"             android:layout_marginTop="15dp"             android:layout_marginRight="10dp"/>          <LinearLayout             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:orientation="vertical">              <TextView                 android:id="@+id/nombreId"                 android:layout_marginTop="10dp"                 android:layout_marginRight="10dp"                 android:text="Nombre producto"                 android:layout_marginBottom="5dp"                 android:textSize="20dp"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"/>              <TextView                 android:id="@+id/precioId"                 android:text="Precio"                 android:textSize="20dp"                 android:textColor="#000000"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"/>             <Button                 android:id="@+id/comprarBttn"                 android:layout_width="230dp"                 android:layout_height="35dp"                 android:textColor="#FFFFFF"                 android:background="#248761"                 android:text="Comprar"/>          </LinearLayout>     </LinearLayout>   </LinearLayout>

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Here's what I have so far: $$\sum_{i=1}^n \frac{1}{\sqrt i} > \sqrt n$$ where $n\ge2$.  Test for base case  $$\frac{1}{\sqrt 1} + \frac{1}{\sqrt 2} > \sqrt 2$$  Simplify  $$ 1 + .707... > 1.414... $$ $$ 1.707... > 1.414... $$  This statement is true.  Thus we can assume $\sum_{i=1}^n \frac{1}{\sqrt i} > \sqrt n$ is true for $\forall n$  Now prove $n + 1$  Expand  $$\sum_{i=1}^n \frac{1}{\sqrt i} = \frac{1}{\sqrt{1}} + \frac{1}{\sqrt{2}} + ... + \frac{1}{\sqrt{n}} \gt \sqrt n $$  Add the next n in the series, and add it to both sides of the inequality.  $$\frac{1}{\sqrt{1}} + \frac{1}{\sqrt{2}} + ... + \frac{1}{\sqrt{n}} + \frac{1}{\sqrt{n+1}} \gt \sqrt n + \frac{1}{\sqrt{n + 1}} $$  Rewrite $$\frac{1}{\sqrt{1}} + \frac{1}{\sqrt{2}} + ... + \frac{1}{\sqrt{n}} + \frac{1}{\sqrt{n+1}} = \sum_{i=1}^{n + 1} \frac{1}{\sqrt i}$$  LHS is complete now we have to try to make RHS = $\sqrt {n + 1}$  $$\sqrt n + \frac{1}{\sqrt{n + 1}} = \frac{\sqrt{n}\sqrt{n+1} + 1}{\sqrt{n+1}}$$  Given that n > 0  $$\frac{\sqrt{n}\sqrt{n+1} + 1}{\sqrt{n+1}} = \frac{\sqrt{n(n+1)} + 1} {\sqrt{n+1}}$$  Now since this is my first induction involving inequalities or summation, I was hoping you guys could show me what the next step would be, since I'm really not sure. Thanks in advance!

I am just starting out learning mathematical induction and I got this homework question to prove with induction but I am not managing.  $$\sum\limits_{k=1}^{n}{\frac{1}{\sqrt{k}}\ge\sqrt{n}}$$  Perhaps someone can help me out I don't understand how to move forward from here: $$\sum\limits_{k=1}^{n+1}{\frac{1}{\sqrt{k}}+\frac{1}{\sqrt{n+1}}\ge \sqrt{n+1}}$$ proof and explanation would greatly be appreciated :) Thanks :)  EDIT sorry meant GE not = fixed :)


Why $\mathcal P(\mathbb N)$ the power set of $\mathbb N$ is uncountable ? Indeed, countable union of countable set should be countable, and since $\mathcal A_n:=\mathcal P(\{1,...,n\})$ is countable, that $$\bigcup_{n\in\mathbb N}\{1,...,n\}=\mathbb N,$$ I don't really see why $$\bigcup_{n\in\mathbb N}\mathcal A_n\neq \mathcal P(\mathbb N).$$  1) So first, what would be $\bigcup_{n\in\mathbb N}\mathcal A_n$ ?  2) And secondly, why $\bigcup_{n\in\mathbb N}\mathcal A_n\neq \mathcal P(\mathbb N)$ ?

I came up with a proof that the power set of natural numbers is countable, which obviously must be a wrong proof.  Here is a procedure to create a one-on-one correspondence between the natural numbers and the elements of its power set.  Starting with the power-set-element-counter k = 1. Go through all the natural numbers x in order (x = 1, x=2, etc), and for each x do the following:   Denote P(x) to be the set of all subsets of the set of natural numbers up to x: P(x) = Power{1,...,x}. Denote P*(x) to be the the set of elements of P(x), excluding the elements in P(x-1).  P*(x) is finite, since the cardinality of a power set of a finite set is also finite. Denote the cardinality of P*(x) as "c". Hence we can pair the natural numbers, starting with k, to each of the elements in P*(x). After each pair that is paired, increment k = k+1. in the end, k will be incremented by c.  set x = x+1, and start the cycle over again.   This cycle should produce a bijection between the natural numbers and the elements of the power set of natural numbers. What is wrong with this proof?


I am confused about this quotient ring.  I know that $\mathbb{Z}_7 [x]/\langle x^2 + 1\rangle =  \{ f(x) + \langle x^2 + 1\rangle \mid f(x) \in \mathbb{Z}_7[x] \}$. Here $x^2 + 1$ is a zero element in $\mathbb{Z}_7 [x]/\langle x^2 + 1\rangle$, so if we replace $x$ by $i$ we get $\mathbb{Z}_7 [x]/\langle x^2 + 1\rangle =\mathbb{Z}_7 (i) $.  I know the distinct element of $ \mathbb{Z}_6 [x]/\langle 2x +4\rangle$ are $\langle 2x +4\rangle,\;x + \langle 2x +4\rangle, \;x^2 + \langle 2x +4\rangle, \ldots$ but I do not  know how to prove this.  Please tell what could we do similar here in case of $ \mathbb{Z}_6 [x]/\langle 2x +4\rangle$? Since $1$ is the zero element of the polynomial $2x +4 $. Why we can not replace here $x$ by $1$?  Any help would be appreciated. Thank you.

Let $R$ be the ring obtained by taking the quotient of $\mathbb{Z_6}[X]$ by principal ideal $(2X+4)$. Then  1) $R$ has infinite elements  2) $R$ is field  3) $5$ is unit in $R$  4) $4$ is unit in $R$.  My Attempt:  \begin{equation*} \mathbb{Z_6}[X]/(2X+4) = \mathbb{Z_6}[X]/(2(X+2)) = \mathbb{Z_3}[X],  \end{equation*} as $X+2$ has root in $\mathbb{Z_6}$. According to me 1) and 3) are correct but I'm not sure about my answer. Help me. I am not more familiar with polynomial and quotient ring. I searched this problem here but couldn't get this here. If this problem is already asked here then how can I get this?  Thank you in advance.


I am an active member of the SharePoint StackExchange forum/community. I would like to add a link and description of my experience as a member of StackExchange on my LinkedIn profile. I am confused as to under which section should I add these details?  Also, it would be really nice if StackExchange comes up with something similar to what Codeschool has implemented... Add to my LinkedIn Profile facility. All we need to do is to click on that link and the course that we completed is added to our LinkedIn Profile.  Edit 1: Codeschool is just a website for online tutorials, offering range of technical courses (Free as well as paid). Check this   After completion of courses they offer certificates and at the end of the course on the Certifiacte/Badge page they provide a link to add that certificate to our LinkedIn Profile. Find the snap below:    Upon clicking this link the course is added under the Certification section of LinkedIn without us having to take any further trouble.

Is it possible to connect Stack Overflow (or other Stack Exchange) accounts with LinkedIn network? Is it possible to insert your stats into LinkedIn?


I have a question about how to best design my React.JS/Flux app.  Does it belong on Stack Overflow or the Programmers community?  I was thinking Programmers, but there's no React or Flux tag on that site, whereas there are on SO.

There seems to be more than a few computer science/programming Stack Exchange networks (is that the correct term?). Stack Overflow, being the first, has by far the most users, questions, and answers.  What is the reasoning for creating the others, and are there clear guidelines for which kinds of questions should be posted? I can see a large amount of potential overflow, many cases of people not getting a good answer to their question, because the person who has the answer isn't browsing that particular network at the moment.  I understand that they were probably created for organizational purposes, but wouldn't it almost make more sense to just have them as categories under Stack Overflow, keep them separated but still connected, instead of making people have to create multiple 'account's, one for each network?  I am sure there was a very good reason to break them up, but as someone that is new to SE, it can be somewhat intimidating to decide which one to post in to ensure you get a good answer. For example, if I am a computer science student, my first instinct might to be to post in the computer science network, until I see that it literally has 1% of the users as the Stack Overflow network, which still seems to be for programming/computer science related questions.  So my second instinct would then to be to post it into the Stack Overflow site on the basis that I have a significantly higher chance of my question being seen and getting a good answer. Then I notice that there is also a 'programmers' network, and I don't even begin to know where that fits in. I, and I am assuming most people, will probably just post on Stack Overflow to be safe.  My question is, other than the short little description blurb of each one, is there a clear cut set of guidelines which what each network is intended for, what kinds of questions should go to each one, and is anything being done to encourage people to post in these newer, smaller (more specialized?) networks as opposed to just posting in big daddy Stack Overflow?  Now again, this is for computer science/programming/"why isn't this code doing what I want?" related questions, I am not saying that if I had a question about Linux or WordPress or something I would have the same confusion.


Give an example(s) of a group $G$ and $H\leq G$ (i.e., $H$ is a subgroup of $G$) where $H$ is not normal in $G$.   What about $S_3$ and $\langle(1\;2)\rangle=\{(1),(1\;2)\}$? [Since $(1\;2\;3)(1\;2)(1\;3\;2)=(2\;3)\not\in\langle(1\;2)\rangle$] Does this work? Any other ideas?

Can you kindly provide an example of a subgroup that is not normal?  I have been told many times that, for coset multiplication to be defined, the subgroup must be normal.  I have seen the proof and examples of quotient group multiplications.  Now, I am trying to find out where the process will break down if the subgroup is not normal.  Suppose that $x \in a_1H = a_2H, y \in b_1H = b_2H$, where $H$ is not normal. So $x = a_1h_1 = a_2h_2$ for some $h_1, h_2 \in H$, and $y = b_1h_1^* = b_2h_2^*$ for some $h_1, h_2 \in H$.  $xy = (a_1b_1)(h_1h_1^*) = (a_2b_2)(h_2h_2^*)$.  However, both $h_1h_1^*, h_2h_2^*$ are still elements of $H$.  So I don't see how $a_1b_1H \neq a_2b_2H$.


Here is the pseudo code. This is specical case btw. >pointsCoverd(x1,...,xn)  >segments <- empty list  >left <- 1  >    while left <= n: >        (l,r) <- (xleft,xleft +2) >        segments.append((l,r)) >        left <- left + 1 >        while left <= n and xleft <= r: >            left <- left +1 return segments >return segments

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


In my program I approaching text files in every iteration of loop to not lost any data from running. It is brutal uneffective and still I lost that data yesterday.  I have 2 Queues - "what have I done" and "what to do". After some time I need to end this application and remember these queues for next app run. I usually kill the applicatiaon with Ctrl+C.  Is there any way to run saving these Queues to files after app kill? Or how to End console application as a User correctly.  Is it possible to run piece of code atomically? I mean when I update some "Queue file" by removing first line of it I need to copy whole file to tmp than delete original file and than copy tmp file to original. But sometimes I hit Ctrl+C right after orig. file delete and I lost one queue.

I have a console application that contains quite a lot of threads.  There are threads that monitor certain conditions and terminate the program if they are true.  This termination can happen at any time.  I need an event that can be triggered when the program is closing so that I can cleanup all of the other threads and close all file handles and connections properly.  I'm not sure if there is one already built into the .NET framework, so I'm asking before I write my own.  I was wondering if there was an event along the lines of:  MyConsoleProgram.OnExit += CleanupBeforeExit;


I recently heard in the brilliant TV show The Night Of, a character saying "he knows not...". As far as I remember my English lessons, the teachers always taught me to say "he doesn't know". Which is correct? Is this an archaic form still used nowadays? Is it slang?

Here's a passage (more or less taken randomly) from the  of the Bible from 1901:      (ASV)   14 But even if ye should suffer for righteousness' sake, blessed are ye: and fear not their fear, neither be troubled;   The bolded words are the grammatical form I'm asking about.  It's extremely common in the older translations of the Bible, which make them difficult to read.  These days, I think most people would say "do not fear their fear" of "don't be afraid of their fear" instead.  In fact, a  reads:      (NASB)   14 But even if you should suffer for the sake of righteousness, you are blessed. And do not fear their intimidation, and do not be troubled,   (There's a footnote on"intimidation" saying "Lit fear", so my first update matches exactly.)  Reading up on  I haven't been able to discover a name for this word ordering or any history about the change.  Can y'all give me some pointers?    I'm not sure if this part of the question is on-topic, but when I find this form would I be safe in mechanically changing it from:     verb not   to      do not verb   Are there instances that will break the meaning by doing this?


Is it?  The car was stolen last night.  or  The car has been stolen last night.  Also which of the following endings is correct?  She bought a little cup which had been filled with butter/has been filled with butter/was filled with butter.  My teacher really made the passive voice complicated for me, especially the past perfect and present perfect parts. I'm really confused, I would appreciate some help.

Non-native speakers often get confused about what the various tenses  and aspects mean in English. With input from some of the folk here I've put together a diagram that I hope will provide some clarity on the matter.  I offer it as the first answer to this question. Consider it a living document. Input is welcome, and good suggestions will be  incorporated into the diagram.    Nota bene: What this is not is a discussion of whether there are  more than two tenses in English. , to which this question is not intended to supply arguments one way or the other.  Here, the aim is to provide an overview of what constructions English-speaking people use for conveying information about actions referring to past, present, and future, and to provide it first and foremost to precisely the people who are likely to use "tense" as a catch-all term in their search, rather than to linguists who know better.  Breaking News There is now an excellent ELU blog article titled  . It is highly recommended reading.


When I asked my coworker where the boss is, she answered me:   He is at the meeting.   Is this correct? I thought it should be:    He is in the meeting.   Because he is physically inside the room having the meeting.

I sometimes get confused whether to use in or at. For example,  Children were not at school yesterday, because yesterday was a holiday. Children were not in school yesterday, because yesterday was a holiday.  Is there a rule of thumb to not confuse in and at?


At the end of the X-Men first class movie, magneto deflects a bullet causing it to render professor X - who was a boy at the time - to become paralyzed in his legs. However in The last stand when Charles and magneto recruit Jean Grey we can clearly see that he's walking!

At the end of First Class, Xavier is paralysed, and him and Magneto split paths. However at the beginning of Last Stand, it flashes back 20 years, and you see the grown up Xavier and Magneto, friends, talking to a young Jean Gray.  Did Xavier get the use of his legs back and then lose it again?  Or is this just a continuity error?


I have obtained my master a couple years ago and am looking into pursuing a PhD. I currently have a part time job completely irrelevant to academia. For applying for a PhD, I figured that I need a research paper, I haven't been totally disconnected from learning in this period and have recently written a paper with a faculty member with me doing all the major part and her evaluating/reviewing. When trying to submit the manuscript to Elsevier, the very first thing I'm required to fill in as the correspondence author is my affiliation, It won't even go to the next step :( I really want to submit my paper to this particular journal. I don't know what to do, should I call the Elsevier offices? would that make a difference? Are there recent corresponding authors in Elsevier with no affiliation. Please let me know anything that might be helpful. I would greatly appreciate it. :)

Recently my paper is reviewed (by a professor from independent third party) and accepted by a journal. But, my employer allows me to publish this paper only without its name there.  Publishing house is expecting affiliation for each author, i.e. I can not leave affiliation as blank.   What should I write as the affiliation?


I want to book a ticket through an online travel agent which combines two airlines. The flight itinerary is A-B-C and C-B. Segment A-B is operated by airline company A1 and segment B-C-B operated by airline company A2.  Can I skip A-B segment of this itinerary and just board in B?

I've a friend that booked a round-trip journey. He booked A-to-B and B-to-A. Somehow he needed to be earlier at location B, so he took a train and did not take the flight from A to B.  When he went to the airport to take the "back home" flight (B-to-A), he was informed that his ticket was canceled because he did not take the A-to-B flight. They canceled the ticket and sold it to someone else.  Is this normal? The company said it was their right to do so, and he could not get the flight back. The company was Iberia.


I came across this question in one of the English standardize tests in my country: It is required that the new student _____ in an extra English conversation course.  enroll enrolled will enroll would enroll is enrolling  The suggested key states that the answer is 1. enroll From my understanding, that choice is correct because we supposed to use present simple tense when stating such factual information. However, why wouldn't it be enrolls since the subject of the verb is new student which is a singular noun? Or that choice is correct because of any other reason or grammar rules?

Why is this sentence correct?     She suggested that he go to the cinema.   I would definitely use goes instead of go.


If I run a car fixing business which I can offers services to every part of USA. Then If I create 1000-1500 pages (or maybe higher than this) which each page has almost the same content but only the location name in each page is unique. Is this bad for SEO? Example of pages:  Car fixing service in Alabama www.example.com/alabama Car fixing service in Alaska www.example.com/alaska Car fixing service in Arizona www.example.com/arizona Car fixing service in Delaware www.example.com/delaware Car fixing service in Georgia www.example.com/georgia and so on ............  The pages may even go deeper in to city or ever deeper like:  Car fixing service in Jefferson City www.example.com/jeffersoncity  Inside these pages the main content are 100% the same but the names of the state or city written in the content are changed according to each page target area. By doing this, is there any bad effect on SEO?. As if i finish all the state names, cities or even more deeper i might have around 1000-1500 pages with the same format.

I'm not sure exactly what these "filler pages" are called, so I couldn't do a proper search.  If I have a business, say a plumbing/heating company in NYC, and I created these HTML pages:  New-York-City-plumbing-company.html Manhattan-plumbing-company.html Brooklyn-plumbing-company.html  New-York-City-heating-service.html Manhattan-heating-service.html Brooklyn-heating-service.html   and the content for each page type was the same, except the name of the city/neighborhood changed, i.e.
[Neighborhood] Plumbing Company

description of plumbing service

[Neighborhood] Heating Service

description of heating service
   Would this be helpful, harmful, or neutral in terms of SEO? I'm a little afraid Google might see that 95% of the content is the same, minus the name of the neighborhood, and punish my site for it.


The code below throws an  AttributeError: 'bpy_prop_collection' object has no attribute 'link'  How does context.scene.objects.link(loxodrome) look in Blender 2.8? import bpy  from mathutils import Vector from math import radians, sin, cos, tan, sqrt, floor  context = bpy.context  def loxodrome_points(spirals, revs, angle_step=10):     a = 1 / spirals     degs = floor(360 * revs / 2)     segs = [radians(d) for d in range(-degs, degs, angle_step)]     points = []     for t in segs:         den = sqrt(1 + a * a * t * t)         x = cos(t) / den         y = sin(t) / den         z = - a * t / den         l = Vector((x, y, z))         points.append(l)          return points   points = loxodrome_points(10, 10) #loxodrome = bpy.data.objects.get("Loxodrome") #if loxodrome is None: if True:     loxocurve = bpy.data.curves.new("loxo", 'CURVE')     loxocurve.dimensions = '3D'     loxocurve.resolution_u = 2     spline = loxocurve.splines.new('NURBS')     spline.points.add(count=len(points) - 1)      for i, bp in enumerate(spline.points):         x, y, z = points[i]         bp.co = (x, y, z, 1)      loxodrome = bpy.data.objects.new("Loxodrome", loxocurve)         context.scene.objects.link(loxodrome)

As part of an existing add-on, I'm trying to create an object and add it to the scene using Python. I followed a Blender Cookbook tutorial found here: . I use the following code to do so:  emptyMesh = bpy.data.meshes.new('emptyMesh') theObj = bpy.data.objects.new("object_name", emptyMesh) bpy.context.scene.objects.link(theObj)   But I get the following error when I try to link theObj to the scene objects:  AttributeError: 'bpy_prop_collection' object has no attribute 'link'   This works just fine in Blender 2.76-2.79, but doesn't work in the 2.80 test build I downloaded. Was there a change to the Python API? Or is this maybe a bug in the test build?


I am used to working with ArcMap but have been playing around with QGIS. When I export a PDF map with ArcMap, the PDF is spatially referenced. This is a handy tool, I can put the PDF map on my iPhone and it tracks my location on the map (even when I'm out in the woods away from cell coverage). It's very handy for forestry work.  Are the PDF maps exported with QGIS also spatially referenced? Is there a plugin that allows for this feature?

Is there any plugin for QGIS which would help me in exporting the map document as a geospatial PDF (similar to Terrago's GeoPDF)?


When I select another object and transform it the Sapling tree generator panel is gone. I can't get it back when I reselect the tree. Is it possible at all to have the panel back?

When you first add a cylinder, you have the option to change the number of vertices, etc, but once you do anything else in blender, it seems you no longer can edit those parameters.   Is there a setting anywhere or an add-on that allows these parameters to be edited later on? If not, how easy would such an addon/feature be to create for anyone reading this?


One usually reads that the functional role of the myelin sheath is being a good insulator, accelerating the speed of action potential propagation along the myelinated axon.  I tried to understand this and came up with these possibilities:    The immediate reason why action potential propagation along myelinated axons is "faster than normal" is a relative lack of leak channels in the membrane. I.e. it is the membrane of the neuron (not the myelin sheath itself) that is a "better insulator than normal". Why there are no leak channels underneath the myelin sheath would be another question. But the myelin sheath would probably be one of the reasons. Thus, it would be an insulator only "indirectly". Or there are leak channels, but there's no place to go for the ions out of the neuron (no extracellular fluid to diffuse to)?In this case, it would be the myelin sheath that is the "immediate" insulator. But the leak channels would be useless. (So why to maintain them?)   So my question is:     Are there significantly less leak channels underneath the myelin sheath than normal,   or not?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental model of conduction tells me that the density of ion gates along the axon should not affect the speed of the AP.   To illustrate, consider a myelinated axon. A wave of Na$^+$ from action potential site 1, a node of Ranvier, rushes into and quickly diffuses down the axon. (It travels in both directions, but backwards is still in the refractory period.) It diffuses through the myelinated region, its concentration always diminishing. Before it attenuates too much, however, it happens upon node of Ranvier 2, where it triggers another action potential. A new wave of Na$^+$ rushes in and the cycle repeats. This should be plain so far.  Now imagine that there is actually a node of Ranvier halfway between node 1 and 2, called node 1.5. The wave of Na$^+$, on its way to node 2, happens to trigger an action potential at node 1.5, from which a wave of Na$^+$ pours in and either boosts the original wave or replaces it by taking its momentum. Now the reinforced wave proceeds to node 2 and triggers it just as soon as, perhaps even sooner than, if node 1.5 had not existed. Repeatedly insert nodes at higher densities until the situation is simply lack of myelination, and we conclude that unmyelinated axons can transmit an action-potential-triggering wave of Na+ as fast as or faster than a myelinated one.  In short, my point of confusion is this: I cannot see how a higher density of gated channels can possibly slow down the wavefront of Na+ that triggers action potentials. If anything, the additional influxes of Na+ should speed up the all-important wavefront, assuming that new waves really "either boost the original wave or replace it by taking its momentum", and also assuming that the wavefront of Na$^+$ is really all-important for signal transmission, and also assuming that the mere presence of (voltage?) gated ion channels in the membrane does not significantly retard the wavefront.  But the usual explanation for why saltatory conduction is faster than continuous conduction (a fact I hope is empirically and unambiguously established) relies on the putative slowing effect of ion channels on the signal fore. Please explain this effect in more detail, if it is not a misconception.


So I have defeated about 5 or so dragons outside of solstheim and absorbed all their souls yet my Bend Will and other shouts still won't unlock. What do I need to do?

So if I understand correctly you can learn new words and the souls will activate these words. I just killed a dragon and when it died it looked like I absorbed the soul but it didn't unlock any of the words I have.   I noticed some dragons actually have a name so do certain dragons unlock certain words?


Ok so I made this post ajax thingy which adds a movie into a div with the following code :     If I would add this manually into the html the jquery script would work and show 'clicked on 1'.  But if I add the movies from a database with $.post it doesn't detect the click.. What can I do?  Here's the code for the jquery script:  $(function(){     $('#search').click(function(){         $.post("search_movie.php", { name : $('#search_crit').val() }, function(data){             rdata = JSON.parse(data);             $('#search_result').empty();             $.each(rdata, function(i){                 $('#search_result').append('');             });         });     });      $('.movie').click(function(event){         event.preventDefault();         alert('clicked on: ' + $(this).attr('data-id'));     }); });   Here's the code for the html part:
     <form method="POST" action="">         <input type="text" id="search_crit">         <select id="search_type">             <option value="name"> By Name </option>             <option value="date"> By Date </option>         </select>         <button type="button" id="search"> Search </button>     </form>

    As you can see I added a movie manually in html and that works... I inspected the other elements added from jquery and they have the class movie and the correct id so I don't know the exact cause. Could you help me?

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.


I'm wondering what total number of possible groups of order n would be if we are counting isomorphisms separately. I mean that if we were to write out the multiplication tables for elements $a_1, a_2, ... , a_n$, what is the maximum number of such tables? Can we make the bound tighter by noting that the table must satisfy the group axioms, or do we need to know something about n?

The number of nonisomorphic groups of order $n$ is usually called $\nu(n)$.  I found a very good survey about the values. $\nu(n)$ is completely known absolutely up to $n=2047$, and for many other values of $n$ too (for squarefree n, there is a formula).  In general, however, $\nu$ is very hard to calculate.  So, I would like to at least have easy to calculate lower and upper bounds for $\nu$. Are such bounds known?


I am curious as to the evolution of the zombie concept. In old horror movies from the 60s and into the 80s, zombies were depicted as "true" undead beings; people who have died and been inhumed, and then mysteriously their corpses are reanimated, with no scientific explanation available.  From Dawn of the Dead (1978), the following is uttered:     Peter: Something my granddad used to tell us. You know Macumba? Vodou. My granddad was a priest in Trinidad. He used to tell us, "When there's no more room in hell, the dead will walk the Earth."    This, to me, created a feeling of uneasiness and inescapable doom. The forces of hell, or nature, or what have you, inflicted this plague on humanity and there really is no "way out" of that.  In the 90s and onwards, zombies changed. They are now "infected" with a virus or some kind of pathogen that resembles a super-charged variant of rabies. In many franchises such as Resident Evil this pathogen is the result of botched scientific experiments. Many of these types of zombies resemble "mutants" and can be extremely large, and even possess intelligence such as the character Nemesis:     The Nemesis-T Type (also known as the "Pursuer") was an experimental form of intelligent Tyrant created by the Umbrella Europe Sixth Laboratory in France under the direct administration of Umbrella Headquarters. Its purpose was to prove that a t-Virus infected creature could retain most of its intelligence and follow specific orders.    Now, I understand that fiction and storywriting is always a reflection of society and the zeitgeist, and it is quite obvious that this "new" type of zombie is very relevant to our brave new world of ebola, swine flu, mad cow disease and other epidemics, as well as relating to stem cells, DNA research, cloning and being a "modern extension" of the classic "mad scientist" story.  But, in these zombie stories, there is always a "way out"; the vaccine, the antidote, the "blow em all up routine". I am curious how the more ominous approach that I described in the beginning of my question, became replaced with the "new approach" and why it seems to have become a main-stay version of zombiism in popular media - my bottom line being that a metaphysical force that cannot be "reasoned with" is much more terrifying than genetic experiments gone awry. Why are these things even called zombies anyway?

In the beginning, IIRC, zombies were undead creatures created and controlled by voodoo priests or priestesses. What work of scifi was the first to break that tradition by depicting zombies as uncontrolled, reanimated dead humans that craved live flesh?


I can't find any new answers to this question. I was just wondering if there is any way that multiple people can work on the same project? I don't mean at the same time. An example of what I am talking about is with the Unreal Engine, there is something called Perforce I think and it when one person is done working on it, they update it on their end, and the next person can "checkout" the file and it updates the changes the other guy did.  Any help will be appreciated!

Me and my team are new to blender, we are now planning for a small project. What I want to ask here are some questions regarding the team work:   We use git for version control in web projects, Is there any special version control for blender project. Creating object of each file and integrating in the project is one way we saw to complete the project. But is there any good way to work in the group?   Please tell us from your experience what might be the best way to work together in a group blender project.


Following up this question about love between Dwarfes and Elves (), I wondered whether there is any incidence of a romance between a dwarf and a man/woman? The question of possible reproduction is not at the center of my question; it is more about falling in love. My own hypotheses are twofold:   just as for the case Elves/dwarfes: While man was created by Illuvatar, dwarfes were created by Aule. That would speak against them having a romantic relationship. Men and dwarfes are both bound to die eventually, making them different from elves.   Please note that this question is not about whether the relationship should be male man -- female dwarf // male-man -- male dwarf // female human -- male dwarf // female human -- female dwarf. However, if there actually IS any difference between those, I'm glad to hear!

I know Tauriel is a Jackson created character, but I wondered if anywhere in the legendarium there was fodder for the story arc between her and Kili.  I do not have access to all my books for the time being and recall stories of love between men and elves in the Silmarillion and Appendices but don't remember any such stories between elves and dwarves and wondered if there was any basis of inspiration for this aspect of their relationship within Tolkien's works.   This movie, of course, departs even further from the original than those made before it, but as a story unto itself, I can still appreciate the ride, so if there is no Tolkien basis, what inspired Jackson, Boyens, and Walsh to create this particular arc?  Is there interview info or anything?


i would like to ask if it is possible to get a token that allows you to receive the html of a lightning or visualforce page given the url. The REST api token doesnt seem to work. For example get the /home page as html in curl. Thank you

We've written some  tests but its been hard work given the  of the code and that the  blocks access to the underlying DOM. I'm now wondering if it would make more sense to run  tests on the components assembled into an app.  I'd like to know what approach to automated testing of Lightning Components others have taken - please share.  PS  One of the big improvements in  looks like testability. So writing those and their tests instead of Aura Components and LTS stuff looks like the best way to go.


Very simple (and potentially stupid question)  What is 'List Slicing' in python and can someone please give an example of list slicing.  Thanks !

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I am coming in from Detroit by flight DL 138 at 11:15 and taking  flight DL 9574 at 12:55 to Delhi on a single ticket. Do I have enough time to connect?

Arriving in AMS in a Delta flight from Bombay at 7 AM. Departure at 7.50 AM in a KLM flight flying to Detroit. On a single leg ticket. Is this going to be time enough? Or should one just bolt as soon as the flight lands?  A google just shows the layout of the airport and there don't seem to be dedicated terminals for airlines.  Edit In case the connecting flight is missed. On a ticket which is non refundable (non - everything - as this was the cheapest ticket), what happens when one misses a connection? Whose responsibility are the next steps? What should be the next steps? Reading other questions about AMS, with 50 minutes, it seems that the luggage is sure to be delayed. Sigh.  Edit 2 It's been a while, but when I was transiting, 50 minutes was pretty ample enough.


I have a table A that I need to join to table B. Table B holds important info including CreatedDate. I want to only return results for the most recent created date. My SQL below appears correct but it is returning multiple results since column Y has multiple distinct values for each row.  (X = Foreign Key, Y = Attribute that changes with each row)  SELECT * FROM TABLE_A T     INNER JOIN       (SELECT X, Y, MAX(CreatedDate) AS Created       FROM TABLE_B       GROUP BY X, Y) SUB ON SUB.X = T.X   How do I prevent duplicated rows and only show the max created date row?  Thanks!

Table:   UserId, Value, Date.   I want to get the UserId, Value for the max(Date) for each UserId. That is, the Value for each UserId that has the latest date. Is there a way to do this simply in SQL? (Preferably Oracle)  Update: Apologies for any ambiguity: I need to get ALL the UserIds. But for each UserId, only that row where that user has the latest date.


I have one scenario in C#, which I fetch the expression from database, I need to parse and evaluate the same  The expression can be of any type (With + & - Operator only) as mentioned below   X+Y-Z X-Y-Z Z-Y+Z   Where as at run time I have any of above expression as string item and the values for each variable defined in it.   Now I need to automate the same, so that my code at run time will able to parse and evaluate the same.  I believe Switch case and if/else loop is the one way, but any can please suggest some other better and efficient way.   Thanks in advance

Is there a function the .NET framework that can evaluate a numeric expression contained in a string and return the result? F.e.:  string mystring = "3*(2+4)"; int result = EvaluateExpression(mystring); Console.Writeln(result); // Outputs 18   Is there a standard framework function that you can replace my EvaluateExpression method with?


This is an exercise from hungerford p.140 and I am totally stuck at it. I denote $S$ to be the collection of all units and all products of primes in the given integral domain $R$. And I showed that $S$ is closed under multiplication and division. Now I assume there is an element in $R-S$. Then the ideal generated by the element is disjoint from $S$. Now I think of a collection of ideals disjoint from $S$. Then by Zorn's lemma there is a maximal element in the collection. Now I want to show that the maximal element is a prime ideal. But I cannot proceed from this point at all and am totally stuck.... Could anyone help me? Or is there some completely different solution?

Let $S$ be a multiplicatively closed subset of a ring $R$, and let $I$ be an ideal of $R$ which is maximal among ideals disjoint from $S$. Show that $I$ is prime. If $R$ is an integral domain, explain briefly how one may construct a field $F$ together with a ring homomorphism $R\to F$. Deduce that if $R$ is an arbitrary ring, $I$ an ideal of $R$, and $S$ a multiplicatively closed subset disjoint from $I$, then there exists a ring homomorphism $f\colon R\to F$, where $F$ is a field, such that $f(x)=0$ for all $x\in I$ and $f(y)\neq 0$ for all $y\in S$.   [You may assume that if $T$ is a multiplicatively closed subset of a ring, and $0\notin T$, then there exists an ideal which is maximal among ideals disjoint from $T$.]  Here is a question I need to answer. For the first part I can show if $x, y$ are not in $I$ then nor does $xy$. The second part is just the field of fractions.   For the third part, I think I need to find an ideal $J$ containing $I$ such $J$ is prime, so that $R/J$ is an integral domain, and use the second part. To find $J$ prime, I think as suggested by the hint, I should go for a maximal ideal disjoint from $S$ containing $I$, but how can I do that?


Given three complex numbers $|Z_1|= 2 , |Z_2|= 3, |Z_3| = 4$ find the maximum value of $$|Z_1-Z_2|^2 +|Z_2-Z_3|^2+|Z_3-Z_1|^2$$      If we treat them as three vectors $a, b, c$ centred at zero the above expression becomes $$2(|a|^2+|b|^2+|c|^2)-2(a\cdot b + b\cdot c + c\cdot a)$$ I've been unsuccessful trying to find the minimum value of $a\cdot b + b\cdot c + c\cdot a$.

If $z_{1},z_{2},z_{3}$ are three complex number Such that $|z_{1}| = 2\;\;,|z_{2}| = 3\;\;, |z_{3}| = 4\;\;$ Then $\max$ of $|z_{1}-z_{2}|^2+|z_{2}-z_{3}|^2+|z_{3}-z_{1}|^2$  $\bf{My\; Try::}$ Let $z_{1}=2\left(\cos \alpha+i\sin \alpha\right)$ and $z_{2}=3\left(\cos \beta+i\sin \beta\right)$ and $z_{3}=4\left(\cos \gamma+i\sin \gamma\right)$ So $$f(\alpha,\beta,\gamma) = 58-\left[12\cos(\alpha-\beta)+24\cos(\beta-\gamma)+16\cos(\gamma-\alpha)\right]$$ Now How can I calculate $\max$ of $f(\alpha,\beta,\gamma)$ Help me Thanks


I'm stuck with the following number theory problem:  Show that $(2^{2^m} + 1 , 2^{2^n}+1) = 1$ for any distinct pair of positive integers $n,m$

I've been working with the Fermat numbers recently, but this problem has really tripped me up. If the Fermat theorem is set as $f_a=2^{2^a}+1$, then how can we say that for an integer $b<a$, the $\gcd(f_b,f_a)=1$?


I am learning how to use prepared statements in my simple login system to make it more secure.  I have followed a few different tutorials to get it working but cant get it to work. When i enter the username and password wrong it gives me the error. When i enter the username and password correct i still get the error.  What am i doing wrong?  I am new to this so apologies for any obvious errors.  I have also looked into hashing my password as it is being stored as plain text in the database at the moment but that will be my next step after i get this working.  Here is my code:  <?php  error_reporting(E_ALL); ini_set('display_errors', 1); session_start(); // Starting Session $error=''; // Variable To Store Error Message  if($SERVER['REQUESTMETHOD'] == 'POST') { if (empty($POST['username']) || empty($POST['password'])) {  $error = "Enter Username and Password";  }  else { // Define $username and $password $username = $_POST['username']; $password = $_POST['password'];  //connect to database include('dbconx.php');  }  $stmt = $con->prepare("SELECT * from admin where password=? AND username=?"); $stmt->bind_param('ss', $username, $password);  $stmt->execute(); $stmt->bind_result($id, $username, $password); $stmt->store_result(); if($stmt->num_rows == 1) //To check if the row exists {          $_SESSION['login_user'] = $username; // Initializing Session         header("location: confirm.php"); // Redirecting To Other Page      } else { $error = "Username or Password is incorrect"; }  mysqli_close($con); // Closing Connection }  ?>

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


My account was banned after I asked 6 questions since early August, three of which were edited by a staff-like person. I only posted some error messages and code that is not working for the CS50 course, and I have no idea what was wrong with this. I edited some of the questions after being banned, so can I now have the ban lifted?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


I'm running a MacBook Air with Catalina 10.15.7 and Safari 14.0.  My homepage is DuckDuckGo but when I click on the homepage icon I get apple.com.  While the page is loading the URL is apple.com/startpage but the finished URL is just apple.com  I have no Profiles icon in System Preferences.  The homepage in System Preferences shows .  I have tried changing it but it goes back to duckduckgo and still opens with apple.com (BTW the apple.com page is an ad for iPhone 12).  This started 2 days ago.  I have used finder to search for numerous known adware sites but nothing has been found. I am not a computer techie, but I can follow directions if anyone can lead me in the right direction. Thanks for your help.  A picture of my Safari preferences is included.  I have no extensions and have forced quit Safari with no positive results

imac 2011 10.10.5  Safari had homepage hijacked and I can't change it back to google.com.  When I go to Safari preferences and try and change, it just immediately goes to www.rack-search.com/....  I tried deleting all the com.apple.safari.plists in library.  Can you help?


Ok. I feel really stupid for asking this but I've been trying to find out how to make a bag of holding for one of my characters and I can't find anything referencing how characters NPC or otherwise would make them nor find a spell that would work.

Are there any class, proficiency, or skill requirements to craft a magic item in D&D 5th edition other than to possess the minimum character levels?   I.e. 3rd level for Common and Uncommon Magic Items, 17th level for Legendary Items.


I have heard that pssh and clusterssh are two popular ones, but I thought I would open it to discussion here and see what the community's experiences with these tools were? What are the gotchas? Any decent hacks or use cases?

I have about a dozen Linux boxes that I occasionally need to run the same command(s) on. Is there an easier way (or automated way) to do this asides from logging on to each machine and running the command, one at a time? It's not the same commands all the time and it's not at a preset time so it's not something ideal for tools like cron.


When I turn my phone on, many apps also turn on in the background. This slows down my phone. How do I shut them down? Why is the OS built this way? Doesn't make sense to me.

When my phone starts up there are several application/services running in the background that I would rather not.  And when I press the Home button while using an app, that app usually goes into the background without exiting.  How can I stop these apps from running?


I am trying to set up an HP .   In the CUPS web interface, I have tried entering root user & pw as well as my user/pw and neither seems to work.  I am able to print, though hplip does not show the printer as a detected device and just sends me to CUPS interface to add...kind of circular and getting nowhere.  I am running Ubuntu (18.04.3).  I already had current hplip print mgr, but it won't show the printer; keeps sending me to CUPS to set it up.

Let's assume that one has some modern HP printer and/or scanner which is not supported by HPLIP package from official repository. Currently Ubuntu versions have :  trusty (14.04LTS): 3.14.3-0ubuntu3.4 xenial (16.04LTS): 3.16.3+repack0-1 bionic (18.04LTS): 3.17.10+repack0-5 focal (20.04LTS): 3.20.3+dfsg0-2 groovy (20.10): 3.20.5+dfsg0-3build1 hirsute (21.04): 3.21.2+dfsg1-2   What can one do if printer is supported in newer version of HPLIP (checked this in )?


I use Gimp to edit photos and then I convert the image to Jpeg but it saves as PNG. How do I convert that to Jpeg?

I used to save images as usual image file formats (jpg, png) by pressing Ctrl+S or Ctrl+Shift+S (Save or Save As dialog). Now in version 2.8 GIMP doesn't allow it anymore: you can Save only as .xcf but to save as .jpg or .png you must Export.  Is there a way to get this old file saving functionality back?


A file in a ls -l listing has permissions such as:  -rw-r-----+   How do I find the extended Access Control List (ACL) permissions denoted by the +?

If the ls -l command gives me a permission string like  rwsr-s--x   What does the 's' mean? The only sources I found mention that it can be present sometimes but do not elaborate.  What does a '+' instead of a '-' mean? I have found mentions of 'extended permission' but nothing clear.


I am interested in doing a PhD in Industrial Engineering and Operations Research at any of the premier American Universities. I have a postgraduate degree in Industrial Engineering from Indian Institute of Technology, Kharagpur, India, which I completed in 1983. I have about 30 years of working experience in India as an Industrial Engineer.

Are there any age limits (formal, informal, or guidelines) that schools use when deciding to accept someone into a PhD program? I'm most curious about the upper age limits. For example, will most schools accept someone in their 40's? How about their 50's?


var e = 10;  function sum(a) {     return function(b) {         return function(c) {             return function(d) {                 return a + b + c + d + e;             }         }     } }  console.log(sum(1)(2)(3)(4)); //logs 20    I'm not quite sure how to read this. It was one of the examples in some MDN documentation. Do you think it would be possible to give a step-by-step narration of what's going on? Here's what I think is happening: I thought sum(1) would return function(b) (which returns function(c) which returns function(d) which returns 1 + undefined + undefined + undefined + 10) but this is obviously wrong.

I've seen references to curried functions in several articles and blogs but I can't find a good explanation (or at least one that makes sense!)


The following expression seems to result in an integer for all $n$: $$\frac13n\left(n(n-3)+8\right)$$ So, how do I prove that, if $n$ is not a multiple of $3$, $n(n-3)+8$ is.

I am not sure if I am doing this right, but I have this:  There exists an integer $k$. $2k =$ positive number  $(2k)^3 - 2k$ [*And this is where I get lost. How does one prove this?]


The word "semi-colon" is used for the symbol ";"; but this is not half of a colon ":": half of a colon would be a full stop ".". So why the usage of the term semi-colon, or half-colon, for a symbol part of which does not appear at all in the colon?

Semi- is a Latin prefix meaning "half" and colon is another punctuation. Should I therefore say that semicolon is a halved colon?


I’m looking for a short story about bird-like aliens who land on Earth. The human race have died in a battle with other aliens, and we had no choice but to destroy our sun.  At the end of the story it becomes clear the the aliens are some kind of birds, when you read the story you think it is about humans landing on an other planet.  Who wrote it and what is it called?

So my dad told me about a short story he had once read. It must be older like before 1986. It is about two men who traveled through space and found a dead planet. On it was what he calls a super museum. They set it up as a heritage/legacy for those in the universe that were intelligent enough to find it. As a twist it turns out that this planet is actually earth and that the men must have traveled to the future. (Kind of like planet of the apes)  I have found a few topics that looked similar. But it's not resurrection bij a.e van Vogt.(because they know it is earth they are visiting) Although this seems very similar. He also says it is not all the way back from michael Shaara.   Anybody have any idea? If it helps, the story was translated to Dutch and was in a book with other stories as well. I don't know if they were from one author or various. It has been bugging me for years as my dad always told me the story moved him deeply and as I love science fiction I would love to read it. Just found this site so thought to give it a go.thanks in advance!


I am looking for examples of rational numbers with large denominators that pop up in questions in which there is a-priori no large numbers involved or no obvious reason why the denominator would be large. (for example $1/\Sigma(11)$  would rather clearly have a large denominator, where $\Sigma$ is the busy beaver function). I'll start with an example to get it rolling. We can consider this problem which asks for diofantine equations with only titanic solutions . So we can obtain a rational with large denominator by simply taking $\frac{1}{n}$ where $n$ is a solution to one of those equations. It would also be great if someone could give an example of a problem in which a certain constant that comes up looks like it may be irrational, but in the end turns out to be rational but with very large denominator. I thought about going through the wikipedia page on  to see if a rational one with large denominator appeared, but none did. Although it is possible this is just because if one was rational there would be no "need" for a special symbol for it. Thank you and best regards.

Consider the Riemann $\zeta$ function. We know that $\zeta(2n)$ is a rational multiple of $\pi^{2n}$ (in particular is transcendental). We also know that $\zeta(3)$ is irrational, and we expect $\zeta(n)$ to be irrational (if not even transcendental) for every $n\in\mathbb{N}$, or at least I would be amazed if - say - $\zeta(5)$ turned out to be rational.     Are there known instances of rational numbers appearing where we would not have expected them?   Of course the notion of "expectation" here is very subjective, so this is a soft question just out of curiosity, since I have the feeling that usually (in my limited experience always) complicated expressions yield irrational ($\mathbb{C}-\mathbb{Q}$) numbers.  As a non-example, we have the series $\sum_{n=1}^\infty 2^{-n}=1$. A series is complicated enough (compared to say a finite arithmetic expression), but of course here we have the explicit formula for geometric series so the resulting $1$ is not really a big surprise.


Looking at the definition of an homeomorphism, this question came to my mind.

What are some examples of functions which are continuous, but whose inverse is not continuous?  nb: I changed the question after a few comments, so some of the below no longer make sense. Sorry.


Trying to understand the 2 formulas and the relations between radius. Common sense will tell me that centrifugal force increases while we are on a curve with a short angle , as newtons law formula suggests, but checking g-force formula it is directly proportional to radius. A bit confuse on which one should be used on centrifugal fluids. What happens to rotating fluids with increasing radius and same rpm or angular velocity, and what happens with fluids with decreasing radius and same rpm or angulsr velicity.

In one formula given below, if the given radius $r$ is larger, $F$ would be lesser. In another formula, if the given radius $r$ is larger, $F$ would be greater.  How is this possible?  Intuitively, if we increase the radius of the circular path, we would need lesser centripetal force to keep it on the path.  $$F=\frac{mv^2}{r}=m\omega^2r$$


I want to let my brother into my world, but it's not working. We even changed the settings on both devices. I am using a kindle fire, he's using an iPad. How can we play with each other?

I want to invite my girlfriend to my world so she could visit my fun-fair, how can I accomplish this?


The first Leto II dies towards the end of book 1 in the Dune series of book and very little is said about him but is it me tines anywhere if he has 'prescience'? He was half Fremen and the son of Muad'dib, although Chani wasn't in the high spice diet she was for the twins in book 2, but was he too young to show any signs?

By the first Leto II, I'm referring to the one born in Dune, who died during the Sardaukar raids. Additionally, I am not necessarily implying that Paul was not the Kwisatz Haderach (because that is its own discussion), I am asking, could the first son have achieved the same "terrible purpose" that Paul saw and Leto II fulfilled.  The first son had the same heritage as the second, and so should genetically be as capable as the later son.   Paul shares some prescient connection with both of them: he knows the instant the first has died, and the vision-sharing experience on the night of the second's birth. This in contrast to him not even knowing Ghanima was born.  Would the genetics alone have led him along the Golden Path?


In C++ we can convert child class pointer to parent, but is there any way to convert it back: from parent, which was obtained from child, give child class back?  I mean:  class Parent {     ... };  class Child : public Parent {     ... };  int main(int argc, char const *argv[]) {     Child* child = new Child();     Parent* parent = child;     Child* old_child = parent; // how to do this??     return 0; }   Thank you for your answers.

What are the proper uses of:   static_cast dynamic_cast const_cast reinterpret_cast C-style cast (type)value Function-style cast type(value)   How does one decide which to use in which specific cases?


We have some 20 machines in the LAN and 3 NAS boxes mounted on all the devices. I want to permanently umount one NAS box from all the machines. I can do the manual way... SSH to each machine umount the NAS and remove the entry from fstab. Any automated way ?  ( I can write a python fab file, but wanted to know if there is any default Linux way.)

I am trying to automate these steps so that I don't need to do this on every machines manually. I need to install latest app server software (abc.tar.gz) on all the unix boxes.  I need to do this in around 12 machines - "machine1" ... "machine12". I have a master machine "machine0" which has abc.tar.gz file so I was thinking to run my script from this machine only and install abc.tar.gz software by following below steps in all those 12 machines one by one. My unix account id is david and my process runs as golden user.  This is the steps I follow if I am installing abc.tar.gz in "machine1":  david@machine1:~$ sudo scp david@machine0:/home/david/abc.tar.gz . david@machine1:~$ sudo stop test_server david@machine1:~$ sudo su - golden golden@machine1:~$ cd /opt/process golden@machine1:/opt/process$ rm -rf * golden@machine1:/opt/process$ exit david@machine1:~$ sudo cp abc.tar.gz /opt/process david@machine1:~$ sudo chown -R golden /opt/process david@machine1:~$ sudo su - golden golden@machine1:~$ cd /opt/process golden@machine1:/opt/process$ tar -xvzf abc.tar.gz golden@machine1:/opt/process$ exit david@machine1:~$ sudo start test_server   How can I automate this so that it can do the same steps in all 12 machines one bye one? I mean install abc.tar.gz in machine1 first, then install on machine2 and go on..  I want to run this script from machine0 only.  Is there any way to automate this?


as you know when we writing list=$(ls -l) all the files added to $list like this :  total 0 drwx------ 7 mine-pc staff 238 Dec 22 11:32 Applications drwxr-xr-x@ 6 mine-pc staff 204 Jan 11 11:00 Applications (Parallels) drwx------+ 21 mine-pc staff 714 Jan 9 22:33 Desktop drwx------+ 33 mine-pc staff 1122 Jan 7 23:43 Documents drwx------+ 83 mine-pc staff 2822 Jan 11 00:42 Downloads drwx------@ 71 mine-pc staff 2414 Dec 22 01:10 Library drwx------+ 21 mine-pc staff 714 Jan 10 23:48 Movies drwx------+ 4 mine-pc staff 136 Sep 27 17:48 Music drwxr-xr-x 5 mine-pc staff 170 Jan 4 16:25 Parallels drwx------+ 9 mine-pc staff 306 Dec 29 13:06 Pictures drwxr-xr-x+ 5 mine-pc staff 170 Sep 27 15:41 Public   how can I insert it to $list like this :  drwx------   7 mine-pc  staff   238 Dec 22 11:32 Applications drwxr-xr-x@  6 mine-pc  staff   204 Jan 11 11:00 Applications (Parallels) drwx------+ 21 mine-pc  staff   714 Jan  9 22:33 Desktop drwx------+ 33 mine-pc  staff  1122 Jan  7 23:43 Documents drwx------+ 83 mine-pc  staff  2822 Jan 11 00:42 Downloads drwx------@ 71 mine-pc  staff  2414 Dec 22 01:10 Library drwx------+ 21 mine-pc  staff   714 Jan 10 23:48 Movies drwx------+  4 mine-pc  staff   136 Sep 27 17:48 Music drwxr-xr-x   5 mine-pc  staff   170 Jan  4 16:25 Parallels drwx------+  9 mine-pc  staff   306 Dec 29 13:06 Pictures drwxr-xr-x+  5 mine-pc  staff   170 Sep 27 15:41 Public

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


please help  i lost 150gb space after deleting the partition via boot camp assistant and the disk utility won't recover it or partition it as one disk  i tried to recover by timemachine but the disk looked the same size and iam afraid the restore wont get the space back

I bought a new SSD with 750 GB and made two partitions: 600 GB and 150 GB. The smaller one was thought to be a Bootcamp partition one day, but to date it was just another unused partition. When I needed more space, I decided to merge these two partitions. The partition was created with Mavericks, the merge was done with Yosemite.  I opened Disk Utility and the "minus" button. Disk Utility told me both partitions would be merged then. However it miserably failed. My main hard disc suddenly had errors which couldn't be repaired and even two of my other external hard discs could not be mounted any longer.  I eventually restored the hard disc from Time Machine, which worked well.  My second partition is now listed as free:    Unfortunately I can't resize the 600 GB partition nor can I create a new partition using the free space.  Diskutil reveils the following:  ~  diskutil list /dev/disk0    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:      GUID_partition_scheme                        *750.2 GB   disk0    1:                        EFI EFI                     209.7 MB   disk0s1    2:          Apple_CoreStorage                         599.6 GB   disk0s2    3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3 /dev/disk1    #:                       TYPE NAME                    SIZE       IDENTIFIER    0:                  Apple_HFS Macintosh HD           *599.3 GB   disk1                                  Logical Volume on disk0s2                                  XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX                                  Unencrypted   Also diskutil brought up this:  ~  diskutil cs list CoreStorage logical volume groups (1 found) | +-- Logical Volume Group 9D2BA4BA-xxxx-xxxx-xxxx-xxxxxxxxxxxx     =========================================================     Name:         Macintosh HD     Status:       Online     Size:         599640592384 B (599.6 GB)     Free Space:   6111232 B (6.1 MB)     |     +-< Physical Volume 29A9A02B-xxxx-xxxx-xxxx-xxxxxxxxxxxx     |   ----------------------------------------------------     |   Index:    0     |   Disk:     disk0s2     |   Status:   Online     |   Size:     599640592384 B (599.6 GB)     |     +-> Logical Volume Family 2FA7892F-xxxx-xxxx-xxxx-xxxxxxxxxxxx         ----------------------------------------------------------         Encryption Status:       Unlocked         Encryption Type:         None         Conversion Status:       NoConversion         Conversion Direction:    -none-         Has Encrypted Extents:   No         Fully Secure:            No         Passphrase Required:     No         |         +-> Logical Volume 7BF42B7B-xxxx-xxxx-xxxx-xxxxxxxxxxxx             ---------------------------------------------------             Disk:                  disk1             Status:                Online             Size (Total):          599282155520 B (599.3 GB)             Conversion Progress:   -none-             Revertible:            No             LV Name:               Macintosh HD             Volume Name:           Macintosh HD             Content Hint:          Apple_HFS   I have tried this:    fsck -fy (The volume Macintosh HD appears to be OK.)   but it wouldn't help. It said I couldn't recover because it wasn't created in a way it would support (sorry for missing the exact message).  I then have learned that Apple_CoreStorage might indicate my disk is encrypted, which might explain why I can't resize it. It doesn't explain why I can't create a new partition to me.  What are my options to make my hard disk available in a single partition with size 750 GB?


This is something I never really got in either Elementary Probability Theory or Advanced Probability Theory because my professors mainly discussed independence between 2 objects. Please tell me if my understanding is right:   Events $A_1, A_2,\dots,A_n$ are independent: For any distinct indices $i_1, i_2, \dots, i_n$   $$P(A_{i_1}, A_{i_2}, \dots, A_{i_n}) = \prod_{i = i_1}^{i_n} P(A_i).\tag{A}$$   This is  $P(A_1, \dots, A_n) = \prod_{i = 1}^{n} P(A_i)$.   Sigma-algebras or Pi-systems $\mathscr{A}_1, \mathscr{A}_2, \dots, \mathscr{A}_n$ are independent: For any distinct indices $i_1, i_2, \dots, i_n$   $$P(A_{i_1}, A_{i_2}, \dots, A_{i_n}) = \prod_{i = i_1}^{i_n} P(A_i)\mbox{ where } A_{i_1} \in \mathscr{A}_{i_1}, A_{i_2} \in \mathscr{A}_{i_2}, \dots, A_{i_n} \in \mathscr{A}_{i_n}.\tag{B}$$  I'm guessing this is not the same as $P(A_1, \dots, A_n) = \prod_{i = 1}^{n} P(A_i)$ for similar reasons (where $A_{1} \in \mathscr{A}_{1}, A_{2} \in \mathscr{A}_{2}, \dots, A_{n} \in \mathscr{A}_{n}$).   However, I saw that in Stochastic Calculus when random variables $Y_1, Y_2, ... Y_n$ are independent, we CAN say that for all Borel sets $B_i$,   $$P\left(\bigcap_{i=1}^{n} (Y_i \in B_i)\right) = \prod_{i=1}^{n} P(Y_i \in B_i).\tag{C}$$  Apparently, that is equivalent to saying for any distinct indices $i_1, i_2, \dots, i_n$ and for all Borel sets $B_i$,  $$P\left(\bigcap_{i=i_1}^{i_n} (Y_i \in B_i)\right) = \prod_{i=i_1}^{i_n} P(Y_i \in B_i)\tag{$C_1$}.$$   I was surprised because I thought $P(\bigcap_{i=1}^{n} (Y_i \in B_i)) = \Pi_{i=1}^{n} P(Y_i \in B_i)$ does not establish $k$-wise independence, but apparently it does.  Is there an analogue of $C_1$ for A or B?  Note: I acknowledge the title may not be very good. Please suggest a better title if needed.

Let $Y_1, Y_2, ..., Y_n$ be iid random variables and $B_1, B_2, ..., B_n$ be Borel sets. It follows that  $P(\bigcap_{i=1}^{n} (Y_i \in B_i)) = \Pi_{i=1}^{n} P(Y_i \in B_i)$...I think?  If so, does the converse hold true? My Stochastic Calculus professor says it does (or maybe misinterpreted him somehow?),  I was  the  that independence of the n random variables was equivalent to saying for any indices $i_1, i_2, ..., i_k$ $P(\bigcap_{j=i_1}^{i_k} (Y_j \in B_j)) = \Pi_{j=i_1}^{i_k} P(Y_j \in B_j)$.  So, if the RVs are independent, then we can choose $i_j=j$ and k=n to get $P(\bigcap_{i=1}^{n} (Y_i \in B_i)) = \Pi_{i=1}^{n} P(Y_i \in B_i)$, but given $P(\bigcap_{i=1}^{n} (Y_i \in B_i)) = \Pi_{i=1}^{n} P(Y_i \in B_i)$, I don't know how to conclude that for any indices $i_1, i_2, ..., i_n$ $P(\bigcap_{j=i_1}^{i_k} (Y_j \in B_j)) = \Pi_{j=i_1}^{i_k} P(Y_j \in B_j)$, if that's even the right definition.  p.17  seems to suggest otherwise. idk  Help please?  Also this:    or    So, this answer is to use the Omega part to establish pairwise independence and ultimately conclude independence. Without that assumption, we cannot conclude independence. Is that right? Why does that not contradict the definition of independence: $P(\bigcap_{i=1}^{n} (Y_i \in B_i)) = \Pi_{i=1}^{n} P(Y_i \in B_i)$ ?


The cover of my passport had deattached from the old passport. I am under F1 status in the US. It happened at a layover and when the immigration officer checked he didn't say anything. Can I still travel with it?

My Indian passport book cover is detached from the main book, but all other information, as well as the book is fine. I am traveling to India in 2 days. What should I do? Will there any problem at the airport?


So I have 1/2 creature, opponent uses shock to kill it, then I answer with my giant growth and opponent responds with another shock. Will my creature survive or die? which spells will resolve first. I cast giant growth on 1/1 creature and enemy responds with shock. Will my creature take 2 damage first because shock is on top of a stack or will giant growth give +3/+3 to that creature until shock hits it?

I'm a relatively new player to Magic: the Gathering. I was reading  to try to understand exactly when it's okay to cast instants (e.g. ) and use some abilities (e.g.  should be tappable sometime during other peoples' turns), but I don't seem to be making much progress: as I come to understand some things, others make less sense.  My confusion is boundless  For instance: to cast  one needs priority. Spells go on the stack, and priority gets passed at some points (I have no idea when), and effects on the stack are resolved when both players have passed priority. But when is that? I can't find any mention of when the other player gets the priority to cast an instant, except on their own turn. Furthermore,  states that during the Main Phase:     505.4. Second, the active player gets priority. Players may cast spells and activate abilities. The active player may play a land.   So players (plural) may cast spells, but only the active player has priority, so only the active player can cast an instant. The turn rules, and the rules on , never mention any point at which the other player gets priority, so when can they possibly Cancel?  In addition, you can only cast a spell when the stack is empty, so the entire stack must be able to be resolved in your turn at some point.  I need an explanation!  I could go on a bit more. There is also  which can be overloaded to "Counter each spell you don't control", which seems like it could only possibly work with an understanding of the stack.  Could someone explain, in simple English:   When can Instants be cast? When can tap abilities be used? What do Instants and abilities have to do with the Stack and Priority?


Why is any number to the zeroeth power equal to 1?  I would think it would be equal to zero, since nothing multiplied by nothing is, well, I would think 0.  But it is 1?  Examples: $(-5)^0 = 1$; $0^0 = 1$; $5^0 = 1$;

Alright, so the idea of an exponent, $x$, is that you are multiplying its base by itself $x$ number of times. With base $5$ and $x=3$, we have that $5^3$ = $5 \cdot 5 \cdot 5$  I understand that the logarithm with base $a$ of $x = c$,  tells us that  $$a^c = x$$  and for $c =$ positive; values for $x$ are greater than $1$, and for $c =$ negative; values for $x$ are less than $1$,  and for $c = 0$, values for $x$ are...$1$.  So in short, I understand how, by means of observation of the graph of $f(x) = \log x$, we can see that $f(1) = 0$, BUT, I see no other way to understand why $x^0 = 1$, apart from the graph and everything around that very point.  I honestly cannot get my head around the idea, "$5$ times itself $0$ times... is one".  Is it that there is no fundamental answer for this but that we simply know by the graph? Or can I truly understand $x^0 = 1$ on its own?