Mounting a Samsung NX -compatible lens to a different camera
Can I use lens brand X on interchangeable lens camera brand Y?
Fundamental group of a torus with points removed Question 5.33 from "Topology and its Applications"  by Baesner is to compute the fundamental group of the torus ($T^2$) with $n$ points removed. I can "see" in my mind that if we remove one point we get a bouquet of two circles. Less clear is what happens when we remove two (or more) points. Any hints? Disable the default app key (super+num) functionality on Ubuntu 17.10 and later I like to switch workspaces via Super+Number. But unfortunately the default behavior in Ubuntu for Super+Number is to select applications from the dock.   Is it possible to disable that functionality? I've tried overriding the keyboard shortcuts but it doesn't appear to be working. Is the Higgs boson an elementary particle? If so, why does it decay? The  is an excitation of the Higgs field and is very massive and short lived. It also interacts with the Higgs field and thus is able to experience mass.   Why does it decay if it is supposed to be an elementary particle according to the standard model? Is an irrational number times a rational number always irrational?  If the rational number is zero, then the result will be rational. So can we conclude that in general, we can't decide, and it depends on the rational number? How do I install the latest stable version of Thunderbird? Why don't I get $e$ when I solve $\lim_{n\to \infty}(1 + \frac{1}{n})^n$? What was Natsume hiding in her closet in episode 11? In episode 11 of Tokyo Ravens, what was Natsume hiding in her closet? When I upgrade from one version of Ubuntu to the next, the upgrade tool rightly disables all my PPAs, so that software compiled for or otherwise tied to the old version of Ubuntu does not interfere with the new version that I just upgraded to.  Is there any way to automatically re-enable and update any PPAs that provide packages for the new version of Ubuntu? For example, suppose I'm currently running Maverick, and I have two PPAs enabled, "foo" and "bar". Suppose that "foo" provides packages for both Maverick and Natty, while "bar" provides packages for Natty only. Is there a tool I could run after updating to Natty that would re-enable my "foo" PPA and update it to point to the Natty packages, while leaving the "bar" PPA disabled? How do I set the page title? I know I could change the page title with drupal_set_title(t('Amy page title')), but when I try it in Drupal 8 I get the There is no such function error.  How can I change page title in Drupal 8? I found the following blog title without a question mark from :     How to ease Afghanistan’s progress in cricket   Is it grammatical, if we don't put question mark in questions of titles? I think this blog title should have been like this:     How to ease Afghanistan’s progress in cricket?   I also found the following blog title from  without a question mark:     Election rigging 101: How to steal a mandate   However, I found a question mark from other blog title of :     Elections 101: What is the ECP and what does it do on election day? Reading the book on which I'm learning English, I've come across a weird (for me) omitting the "to" in sentence: "I'd better go meet with him then."  Say, if it were "I'd better go to meet with him then.", would there be any difference between the two sentences? When I should prefer using one instead the other?  P.S. Sorry for my bad English. If I made a mistake somewhere, please correct me. NRPE unable to read output, but why? I want to do research but I'm too old for a PHD I really love research. I started a research project in graduate school for my M.A. in English. My research topic is a very viable and interesting topic for a dissertation. I'll be 60 on my next birthday and I know that many Ph.D programs are traditionally geared toward younger students.I was wondering are there any programs that I can continue this research in without facing the issues of ageism in academia? Is the unit sphere in $\Bbb R^4$ path connected? The speed of light is the same in all inertial frames.  Does it change from a non-inertial frame to another? Can it be zero?  If it is not constant in non-inertial frames, is it still bounded from above? How to stop kernel messages from flooding my console? I'm using Centos 6, rsyslog logging. Console is flooded with kernel messages.  Klogd is not running (I'm using rsyslog) Rsyslog config does not direct anything to the console Even tried stopping rsyslog altogether  Still something is flooding my console with kernel log messages. What it is and how do I make it stop? Update: These are the messages generated by the kernel (hardware, iptables, etc.), stuff that goes out of /proc/kmsg, like this:  Shorewall:pub2loc:DROP:IN=br0 OUT= MAC=xxx SRC=xxx DST=xxx LEN=60 TOS=0x00 PREC=0x00 TTL=128 ID=15731 DF PROTO=TCP SPT=63767 DPT=3493 WINDOW=8192 RES=0x00 SYN URGP=0 Find all Quotient (or Factor) Groups of $D_4$ (Dihedral Group of order $8$) I need to be able to find all of the quotient groups for dihedral group 4 with $D_4 = \{ e,R,R^2,R^3,V,H,D,D'\}$. I know I have to start by finding the normal subgroups, which are $\{e,R^2\}$ $\{e,R,R^2,R^3\}$ $\{e,R^2,V,H\}$ $\{e,R^2,D,D'\}$. Then I need to find the sets defined by $G/H=\{ aH : a \in G\}$ with operation $aH  bH = abH$. I am stuck here; could someone please show me how to find all of the factor groups for D4? Prevent suggested edits under 10 reputation on protected questions Recently, . The specific  is protected:  protected by  ♦ Apr 27 '11 at 1:10 This question is protected to prevent &quot;thanks!&quot;, &quot;me too!&quot;, or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.  Great, so 10 reputation is required to answer the question. This doesn't stop anonymous and new users from spamming edit suggestions. Could the same restriction be applied to suggested edits to the protected question and its answers? As this would only apply to protected questions, which evidently attract not-so-good attention, it would not hinder new and anonymous users' ability to edit for the most part. In the film Thor, Odin casts a spell on Mjolnir and strips Thor of his power.  He then banishes Thor to Midgard (Earth).  On Earth, Thor is seemingly just a strong and durable human.  Later in the film, he becomes worthy, and regains control of Mjolnir.  This then grants him his full power set and control over Mjolnir.  My question is, prior to this, could Thor control lightning all on his own?  Or is this purely an ability of Mjolnir? (Built-in) way in JavaScript to check if a string is a valid number I'm hoping there's something in the same conceptual space as the old VB6 IsNumeric() function?