As the title suggests. Is there a prediction of quantum mechanics that could be construed as representing an "energy-time uncertainty relation?" Does there exist any reference to such a prediction, or is it obviously false on some level?
In non-relativistic QM, the $\Delta E$ in the time-energy uncertainty principle is the limiting standard deviation of the set of energy measurements of $n$ identically prepared systems as $n$ goes to infinity. What does the $\Delta t$ mean, since $t$ is not even an observable?
A PCI Express 3.0 Video Card into a PCI-E 1.0 x16 slot Perhaps I'm trying to push my mobo too hard, but I think I have read that PCI-e 3.0 is back compatible to previous PCI-e specifications. But 3.0 into a 1.0, is it possibly asking too much?  I'm thinking about buying an AMD . My mobo is an Asus p5g41-m le How can I see the phone number dialed after I initiate a call? How to rsync files between two remotes? I would like to transfer files between two remote hosts using on local shell, but it seems rsync doesn't support synchronisation if two remotes are specified as follow:  $ rsync -vuar host1:/var/www host2:/var/www The source and destination cannot both be remote.   What other workarounds/commands I could use to achieve similar results? When should I upgrade my camera body? As the question says, when should I upgrade my camera body? In particular, if I have a low- to mid-range body (A DSLR such as a Nikon D3200 or Nikon D5100, or Canon SL1 or T5, or a mirrorless camera such as a Panasonic GH3 or an Olympus E-PL6). How do I know when I need to upgrade?  I have a complement of "kit" lenses, such as an 18-55mm f3.5-5.6 and a 55-200mm f4-5.6. Maybe I've even added a 50mm 1.8 to the kit. Flash is only for indoors (right?) and I usually shoot outside, so that means I don't need an external flash.  I shoot photos of my family and friends whether out at the park or having a picnic, my kids sports practices and games, vacation photos, as well as some landscapes, flowers, and whatever else catches my eye. Pretty familiar territory. I'm not a professional and don't intend to become one. Silencing "Your disk is almost full" notification Syntactic characterisation of the intersection of CTL and LTL How do the Treasure Goblins work? Every once in a while I'll come across the sneaky devils and they always flee.  What determines when they flee (time, distance, etc.) and do I get better loot by killing them faster?  Is there anything else I should know in order to get the most out of the encounter?  EDIT: What I mean is: Is the final drop better based on how effectively I defeat them? I'm looking for a free RAW editor/converter on Windows. Can you tell me some strong/weak points of them comparing with Capture NX and/or Adobe Photoshop Elements?       - conversion &amp; EXIF  - white balance  - registration not possible anymore   EXIF editing would be a nice bonus.  Related: I heard about nautilus-gksu and would like to install it. Unfortunately, when I try, I get this:  glemi@XPS:~$ sudo apt-get install nautilus-gksu Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package nautilus-gksu   How and where can I get this package? Labelled spanning trees of $K_n-e$ Let $e$ be an edge of $K_n$- the complete graph on $n$ vertices. Prove that the number of labelled spanning trees of $K_n-e$ is $(n-2)n^{n-3}$.  I think the answer lies in using some modified form of Prüfer's sequence but I can't quite nail it. Ruby can add methods to the Number class and other core types to get effects like this:  1.should_equal(1)   But it seems like Python cannot do this. Is this true? And if so, why? Does it have something to do with the fact that type can't be modified?  Update: Rather than talking about different definitions of monkey patching, I would like to just focus on the example above. I have already concluded that it cannot be done as a few of you have answered. But I would like a more detailed explanation of why it cannot be done, and maybe what feature, if available in Python, would allow this.  To answer some of you: The reason I might want to do this is simply aesthetics/readability.    item.price.should_equal(19.99)   This reads more like English and clearly indicates which is the tested value and which is the expected value, as supposed to:  should_equal(item.price, 19.99)   This concept is what  and some other Ruby frameworks are based on. In the sentence: "I didn't know she had a son,"   Can I say "I didn't know she has a son" instead, because he is a teenager now?  Or are both correct? I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this? build folder usage issues Conveying "under the radar" in a less colloquial way I am searching for a word to contrast with iconic  I want to characterize views of the city as both iconic and under the radar, maybe "non-iconic."  I was thinking about saying that a view of the city was undiscovered, but I think that maybe that overstates what I'm think-- I more mean under-appreciated. Are there any other words that come to mind? How can I minimize Thunderbird 60.2.1 to tray after "MinimizeToTray revived" add-on stopped working? After update, my Thunderbird stopped getting minimized with the "MinimizeToTray revived" add-on. Is there any way to minimize my Thunderbird? Any other add-on that works with the new version? Date Format In RUBY Enable F1-F12 keys without Fn on Lenovo Ideapad S400u Change running heads in longtable (or other "long table" package) What are our policies regarding self-harm and suicide? What should I do as a Moderator when I encounter situations regarding self-harm and suicide?