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An operator on the other side of the Schrödinger equation A form of the  is  $$     \left[-\frac{\hbar^2}{2m} \nabla^2 + V(\vec{r}, t)\right]\Psi = i\hbar \frac{\partial}{\partial t} \Psi $$  The bracketed term is of course the Hamiltonian, and the whole equation can hence be written as  $$     \hat{H}\Psi = i\hbar \frac{\partial}{\partial t} \Psi $$  My question is, is there a existing/named operator represented by $i\hbar \frac{\partial}{\partial t}$? That is, can we further rewrite the equation as  $$     \hat{H}\Psi = \hat{\Theta}\Psi $$  For some predefined operator $\hat{\Theta} = i\hbar \frac{\partial}{\partial t}$? There are two syntaxes for command substitution: with dollar-parentheses and with backticks. Running top -p $(pidof init) and top -p `pidof init` gives the same output. Are these two ways of doing the same thing, or are there differences? When applying dropout in artificial neural networks, one needs to compensate for the fact that at training time a portion of the neurons were deactivated. To do so, there exist two common strategies:   scaling the activation at test time inverting the dropout during the training phase   The two strategies are summarized in the  below, taken from .  Which strategy is preferable, and why?    Scaling the activation at test time:    Inverting the dropout during the training phase: Something I did in the first Animal Crossing was make a house on an alternate character solely to showcase bugs/fish I felt were too cool to only leave in the museum. However bugs can't be mailed or dropped, so I'm at a loss as to how to do this.  Is there a way I can give bugs/fish to a second character or will that character have to find them themselves? Is a noisy laptop fan caused by dirt on the fan? I got a Sony Vaio laptop VPCSA and its fan is noisy intermittently. At times it is very noisy and at other times it is pretty quite. I wonder whether this is caused by dirt on the fan that I can clean or leave the laptop to a computer repair shop so that they can service is? Or do you think that the noisiness from the fan is caused by some other factor than dirt since the noise is intermittent and not all the time?  Update  I see there're some more suggestions how to fic the problem in another question For example, on this page:   I see the following:   What does this 499 mean? I can't seem to correlate it with upvotes, posts, edits or anything else. Irreducibility check for polynomials not satisfying Eisenstein Criterion. How to disable Windows 10 memory compression? my former wrong assumption: it drains my notebook battery and I've no shortage of RAM. In Task manager you see ntoskrnl.exe is eating more CPU time than any other process. this feature does not appear to be optional and came 2 days ago with the 1st Win10 Update (Win10Pro in my case).  Edit:  I want to disable it, at least to exclude it as a culprit for my (unproven) assumptions. That process never came to my attention in the last 2 months and in task manager's long name it's called "system memory and compressed memory". Retaining all fishnet grid squares within boundary of polygon from another feature class? I have created a fishnet grid (3km x 3km) over a vector polygon.   I now want to clip the fishnet over the vector polygon retaining all grid squares within the boundary of the polygon.   Therefore I want all squares that would typically be clipped into partial squares to remain as whole squares.   Does anybody know how to do this? Complement of maximal multiplicative set is a prime ideal How can I "normalize" the scale of what seems to be either an infinitely large or infinitely small object I'm having issues with an obj file I've imported into Blender. At first I thought the import was broken in some way because the import would go smoothly, but there was no model to be seen. Eventually I figured out that I could snap my view to the object by pressing . on the numpad and it was in fact there, just extremely small or large (I can't tell). I've tried scaling, but the sizes are so extreme that it doesn't seem to be working. Also due to the extreme nature of the object I can only see certain parts of it at a time depending on the angle in which im viewing it at it starts to de-render the parts not directly in front of the camera. Combinatorics Distribution - Number of integer solutions Concept Explanation I reading my textbook and I don't understand the concept of distributions or number of solutions to an equation.  It's explained that this problem is 1/4 types of sampling/distributions problems.  An example is provided to illustrate:     In how many ways can 4 identical jobs (indistinguishable balls) be distributed among 26 members (urns) without exclusion (since one member can do multiple jobs)?      A sample outcome might be:   $\text{_____________}$   |  A  |  B  |  C  |...|  Z  |    $\text{--------------------}$      $\text{_____________}$   |  o  | oo|    |   |    ||| o  |    $\text{_____________}$   |  A  |  B  |  C  |...  |  Z  |    $\text{--------------------}$      Thus, the question is reduced to, "How many $(26-1+4)$ letter words are there consisting of four circles and $(26-1)$ vertical lines?"  Therefore, the solution is:  $\binom{26-1+4}{4}$   I really don't understand why its $(26-1+4)$.  There's only 26 different spots or "urns" to place the 4 jobs.  Can someone please explain?    I looked through another text to try and understand and I found it explained as such:       There are $\binom{n+r-1}{r-1}$ distinct nonnegative integer valued vectors $(x_1,...,x_r$ satisfying the equation $(x_1 + ... + x_r = x_n$ for $x\ge0$. $\spadesuit$   How in the world are they deriving this?  For distinct positive integers I understand:  Assume I have 8 balls (n=8) and I have 3 urns (r=3): o^o^o^o^o^o^o^o, where o represents  a ball and ^ represents a place holder where an urn could be placed.  For this scenario:     There are $\binom{n-1}{r-1}$ distinct positive integer valued vectors $(x_1,...,x_n)$ satisfying the equation:  $x_1 + ... + x_n = n, x_i&gt;0, i=1,..,r$ $\clubsuit$   It's clear that I could have this specific case ooo|ooo|oo.  Here the bar represents a divide for the urn and you see I have 3 sections.  So that case is clear.  Can anyone please explain this problem to me?  I don't understand the nonnegative integer case.   Also, people who post tend to be crazy smart and explain things very in a complicated manner.  I'd appreciate it if it could be explained in layman's terms as much as possible.   Thank you!!! Why are these numbers not equal? What's the simplest SQL statement that will return the duplicate values for a given column and the count of their occurrences in an Oracle database table?  For example: I have a JOBS table with the column JOB_NUMBER.  How can I find out if I have any duplicate JOB_NUMBERs, and how many times they're duplicated? Will using 'var' affect performance? How do I make a 2D game resolution independent? How can I see the photo settings like f-stop, ISO etc. of a image? I am new to photography and enjoying shooting with my Nikon D3200 camera. Once I take a photo, is there any tool by Nikon or a third party which can give me info like F-stop, ISO, Shutter speed, etc? If there is no tool, does Nikon camera support this after the photo is shot? Messed up my PATH environment variable and can't login to desktop To get an maven environment variable to run, I tried several options. Basically, I followed some options from , such as ~/.pam_environment, /etc/bash.bashrc and I don't really know anymore. Within them I exported sth like export PATH=/opt/apache-maven-3.6.0/bin:$PATH (I'm being so unconcrete because I cannot look it up).   Afterwards, I did run gnome-session-quit and my machine got stuck.   So after hard restart I try to login again, but I'm not able to do that: I see my username, enter the password, hit enter, screen turns black and after 2 seconds I'm back at the login screen.   So, that very strange and worrying. Next step: Login via tty (Strg + ALT + F3). Within there I can login, but can not do much. I thought about sth like . But whatever I do: The command could not be located because '\bin' is not included in the PATH environment variable. I think, altogether thats alarming and I'm getting really nervous.  Executing export PATH="/usr/bin:$PATH seems to work and echo $PATHgives an output starting with /usr/bin:/usr/bin:/usr/bin:/home/user/Documents/.../esper/examples/transaction/etc:/home/user/anaconda3/bin:/usr/lib/jvm/java-1.8.0-openjdk-amd64/bin:/opt/apache-maven-3.6.0/bin:/opt/apache-maven-3.6.0/bin:/opt/apache-maven-3.6.0/bin but does not really help.  I'm running an Ubuntu 18.04 on an Lenovo G50-70.   Can you help me accessing my desktop again and/or fixing my PATH issue? Derivation of Mode of grouped data A formula to calculate the mode for grouped data's is given in my text book: Mode = $l + \dfrac{(f_1 - f_0)h}{2f_1 - f_0 - f_2} $ Where, $l = $ lower limit of the modal class, $h = $ size of the class interval, $f_1 = $  frequency of the modal class, $f_0 = $ frequency of the class preceding the modal class, $f_2 =$ frequency of the class succeeding the modal class. Can you please explain the derivation of this formula, as it is not given in my T.B. Thanks . How to contact Canonical? So I am doing a College research project for my Computer Information Systems department and it is about alternative Linux server distribution for small businesses. From my findings I would really like for this research to actually take off into a Distribution project (Using Ubuntu as a base OS).   However I would like to rename the distribution as "Bizbuntu" or something related to that ("Biz" being shorthand for business) however I don't know if I can name the distribution without consent from Canonical.   So my question is do I have to contact Canonical about this, if so, does anyone know a mailing list or email that I can contact them about this?