Qualitative study of the solution to a Cauchy problem
Differential equation $y''=\frac{y'}{2\sqrt y}$
I unplugged my USB stick from Ubuntu 16.04 without the save remove option, but exfat should be fine doing so. No read write was happening, the partition does not use journaling. What I end up with is an unmountable USB stick with checksum error.   What tools are there to recover the partition table or at least the data on the USB stick? What I am doing now is scanning via parted. Has anyone experienced the same problem with exfat and recovery options? Unfortunately parted probably won't detect the partition because .  I also tried to use Partition Wizard on Windows but it failed to detect anything, just showing unallocated space. How do I proceed? are there helpful tools under Windows or Ubuntu?    I also tried to use gpart -v /dev/sdb but it failed to detect anything. On OS X there is a tool called fsck_exfat, is there any on Windows?  update The disk is preinstalled with Parted Magic. After quick search no partition shows up. In Harry Potter, what kind of home life do those born to a wizard and a Muggle have? Show that $\frac 1{1+x+y^{-1}}+\frac1{1+y+z^{-1}}+\frac1{1+z+x^{-1}}=1$ if $xyz=1$ What's the canonical way to check for type in Python? What is the best way to check whether a given object is of a given type? How about checking whether the object inherits from a given type?  Let's say I have an object o. How do I check whether it's a str? How to use "fit" to frame the nodes and labels Finding all functions $ f : \mathbb N^*\to\mathbb N^*$ such that for every $ x , y \in \mathbb N ^ * $, $ f ( x ) + f ( y ) \mid x ^ n + y ^ n $ Let $\mathbb N^*$ be the set of positive integers and $n$ be a fixed positive integer. How many functions $ f : \mathbb N^*\to\mathbb N^*$ are there such that for all positive integers $x$ and $y$, $f(x) + f(y)$ divides $x^n + y^n$? Casting a Somatic, non-Material spell while holding a focus In  a side issue came up of whether you can cast a spell with Somatic components but no Material components while holding a focus in the hand used for Somatic components.  My reading of the rules sees "A spellcaster must have a hand free to access a spell's material components--or to hold a spellcasting focus--but it can be the same hand that he or she uses to perform somatic components." - it doesn't say you have to be holding the focus for the purpose of avoiding materials.  However, @Adeptus and @enkryptor argue that - since that rule is in the section on Material components - you don't consult it in for spells without Material, and fall back to the Somatic rule "the caster must have free use of at least one hand".  (I also appeal to the logic of fluff - why should it be harder to cast a spell with fewer components?)  Is there an official RAW or Word Of God on this matter? Can you cast a material-less, somatic spell while holding a focus in your only free hand? If I upload my brain into a computer is it still me? I think the answer is yes but I know a lot of people disagree. So, I would like to ask these people when exactly does it stop being me.  Let's say I want to upload my brain into a computer using the following procedure:  I have each of my neurons replaced by electronic neurons. By electronic neurons I mean chips with the necessary hardware and software to perform the exact same function that the neuron being replaced was performing. This means that given the same inputs that the biological neuron was given it would produce the same outputs. Then I connect that electronic neuron to all the neurons that former biological neuron was connected to.   At the end of this process is it still me? If not when did it stop being me? When one neuron was replaced? When 1,000 were replaced? When 1,000,000 were replaced?  (assuming it is still me)  Then, I divide these electronic neurons into groups and for each group I perform the following:   Write software to simulate the group of electrical neurons in my computer such that given the same inputs that go into the group of electronic neurons in my brain, it will produce the same outputs. Replace each group of neurons with another chip that communicates with my computer. Each of the chips will communicate to the corresponding software module in order to determine how to transform its inputs into the necessary outputs. Connect all of the inputs and outputs of the group of electronic neurons to that new chip.   At the end of this process is it still me? If not when did it stop being me? When one group was replaced? When 1,000 were replaced? When 1,000,000 were replaced?  (assuming it is still me) Now, what I have is a bunch of these new chips in my head, connected to each other and for each of these chips I have a small neural network software module in my computer. So, now for each pair of chip/software module I do this:   Transfer all connections going into and out of the chip into the computer version (i.e. connect the software module to the other software modules that represent the other chips that this chip is connected to) Disconnect the chip from the other chips and remove it   At the end of this process is it still me? If not when did it stop being me? When one of the new chips was replaced? When 1,000 were replaced? When 1,000,000 were replaced?  If it is still me then I have successfully moved my brain into a computer without ceasing being myself.  So, again the question is if at the end it is not me anymore when exactly does it stop being me and why does it stop being me?  EDIT: This question assumes that our universe and everything in it (including ourselves) follows the (testable) laws of physics. As it stands it also assumes that neuroscience is mostly right, although the question could also be considered without that requirement if instead of neural simulations we were to implement physics simulation of the brain. Of course this is a lot less practical. However, if your view is that our minds have a supernatural component then the question does not make any sense.  It was also pointed out that this is related to the Ship of Theseus, i.e. is something still the same if all its parts have been changed. With regards to that I think it is useful to consider that most of the cells in our body (not including brain cells) are regularly replaced anyway and some people even get entire organs replaced. Yet, we don't say that they stopped being themselves. Note, however, that if you are assuming a supernatural component of the mind that this explanation is not really adequate or relevant. What's the simplest way to do a find and replace for a given input string, say abc, and replace with another string, say XYZ in file /tmp/file.txt?  I am writting an app and using IronPython to execute commands through SSH &mdash; but I don't know Unix that well and don't know what to look for.  I have heard that Bash, apart from being a command line interface, can be a very powerful scripting language. So, if this is true, I assume you can perform actions like these.  Can I do it with bash, and what's the simplest (one line) script to achieve my goal? I recently updated my profile bio (from Arqade) and clicked 'Save and copy changes to all public communities'. This appears to have broken/reset my profile picture on all but Arqade. Note that I did not update my profile picture as part of my changes. Arqade:  Meta SE for comparison:  I haven't touched my profile picture in years. Is this a bug?  Update: It appears my profile pic across all communities has been set back to 'Identicon'. I went on to Stack Overflow and changed my profile picture back to 'Gravitar' and clicked 'Save and copy to all communities' again, but this did not update my profile picture anywhere but SO. (I did the same on Sustainability to be doubly sure). Update 2: This is a persistent bug - I had changed most of my SE communities back to my 'Robotnik' display pic over the past little while. Today I edited my profile again on Arqade, Clicked 'Save and copy' - and the display pic reverted back to identicon again across all sites. Update 3: I have re-uploaded my profile picture and the 'Save and copy' function worked. It appears that this is actually a bug to do with the old images from Gravatar. Is there any efficient algorithm for finding subgroups of a given finite group? I am implementing an algorithm which finds every subgroup of given group.  Here's my algorithm.  Let $G$ be a group of order $n$ with elements $g_1,\cdots,g_n$.  Then I consider each $\langle g_i\rangle $ which are all cyclic subgroups of $G$.  Of course, if $\langle g_i\rangle =\langle g_j\rangle $, we append only $\langle  g_i\rangle $ into our result set.  We call all distinct subgroups of the form $\langle g_i\rangle $ to be the first-generation. (Note that the number of the first-generation subgroups is at most $n$.)  To get $(i+1)$-th generation from $i$-th generation inductively, we construct the subgroup $S$ from each two elements of $i$-th generation $S_1, S_2$ to be  $$S=\langle S_1,S_2\rangle .$$  Obviously, if generated subgroup is already in previous generations, we do not call it $(i+1)$-th generation, hence every subgroups of $G$ has the unique generation number.  We do this construction until the number of the typical generation subgroups to be $0$, since we get all subgroups of $G$.  This works perfectly to any groups, but unfortunately, it is not fast although I implemented additional steps to avoid repeated computation.  So I searched some other algorithms but they are all vague to understand.  One of the algorithm is called the cyclic extension algorithm, but I can not get it easily unless I have studied some backgrounds for this method.  If you have enough knowledge about the cyclic extension algorithm or some other algorithms, please give me an easy explanation. I am in undergrad. course of math dept. Thanks. Why does Java have an "unreachable statement" compiler error? How to extract the n-th elements from a list of tuples? Why did Slytherin House not get disbanded? Should I let potential employers know I have a job offer? I've interviewed for a few positions, one of which has made me an offer.  I'm very pleased with the offer, but I prefer some of the other positions.  I have the luxury of being able to take a lot of time to decide whether or not I accept this offer, so I'm certain I will hear back (either positively or negatively) from the other positions before a decision is required for the offer I've received.  I'm trying to decide between two courses of action, and I want to choose the one that will best help my candidacy with the positions I've yet to hear from.  Plan 1 is to do nothing and simply wait to hear back from the other positions for which I've already interviewed.  Plan 2 is to be in touch with the other positions to let them know I have an offer, and ask where I stand with them.  Would Plan 2 make me a more desirable candidate with the other positions, as they might see my offer as further validation of my credentials?  Or, might initiating with the interviewers in this way be detrimental to my candidacy, perhaps making me seem pushy or self-centered?  If so, I would rather just wait for them to run their course of action (Plan 1).  As I've said, I have plenty of time, so I don't want impatience to hurt me.  If there is a good chance that my meddling will be detrimental, then I'd rather be hands-off here.  However, if it's more likely that informing the other interviewers of my offer will give me a boost, then I'd want to do so.  Thanks for any clarity you can provide!  Edit: For a bit more information and context, the position I've been offered is a non-academic research position that my advisor has described as "prestigious."  The other positions for which I've interviewed (and which I prefer) are mostly academic teaching-centered positions (visiting assistant professors, tenure-track at smaller four year institutions). How to log out of a Stack Exchange site? I used to work as a consultant and have been spoiled with nice looking slides. For instance, being able to create slides that have 2, 3, or 4 graphs (perfectly positioned and with nice headers!) at the click of a mouse button via macros.  Similarly, there are many other kinds of word slides that had multiple columns, etc. that would be nice to recreate as well as objects like "main point" boxes at the bottom that summarize a main point and ways to add a transparent highlight to any part of the screen.  Is this kind of functionality far beyond anything that LaTeX presentations can do or is there an archive somewhere of code for making more intricate presentations? Automatically login and lock User cards are no longer showing reputation or badges across the network How do the radian have a unit?