Passive Wisdom (perception) is common and we use it often. But I read on this forum that there are other passive stats. My Question is now what other passive stats exist and when should you use them?
I understand how Insight and Perception can be used passively: for the DM to determine if an enemy Deception or Stealth attempt is successful without alerting the players that someone is deceiving or sneaking.    But the Observant feat in the Player's Handbook states:      [...] You have a +5 bonus to your passive Wisdom (Perception) and passive Intelligence (Investigation) scores.     So in what situation would a DM be rolling something against the player's Investigation without letting them know?
Why are only certain shutter speeds or apertures available? How do I remove an element from a list by index in Python?  I found the list.remove method, but say I want to remove the last element, how do I do this? It seems like the default remove searches the list, but I don't want any search to be performed. I'm studying machine learning and every book I open I bump into chi-squared distribution, gamma-function, t-distribution, Gaussian, etc.   Every book I have opened so far only defines what the distributions are: they don't explain or give the intuition on where the specific formulas for the functions come from.   For example, why is chi-squared distribution the way it is? What is the t-distribution? What is the intuition behind the distribution? Proofs? etc.   I would like to have a clear and fundamental understanding of the most commonly used distributions so that every time later on when I see them, I truly understand what is a t-distribution, what is a Gaussian distribution and most importantly why are they the way they are.   It would be nice if the books / tutorials  can explain the concepts to a layman so that in order to understand them you don't already need to understand them x) Many books are like this, they don't fit for beginners :( Execution order of event receivers and workflow on a list "Recent Badges" list is displayed without margins on "Home" page When the &quot;Hide Hot Network Questions&quot; preference is enabled (i.e. HNQ sidebar is hidden), we see &quot;Recent Tags&quot; and &quot;Recent Badges&quot; in the homepage instead of the HNQ. However, the &quot;Recent Badges&quot; list is displayed with no margins. ex.)   I think that the appropriate margins were set in the past. cf.) Undefined control sequence BibTex This is one of the BibTex entries giving the problem:  @ARTICLE{2015ApJ...808L..36B,    author = {{Bonnivard}, V. and {Combet}, C. and {Maurin}, D. and {Geringer-Sameth}, A. and      {Koushiappas}, S.~M. and {Walker}, M.~G. and {Mateo}, M. and      {Olszewski}, E.~W. and {Bailey}, III, J.~I.},     title = "{Dark Matter Annihilation and Decay Profiles for the Reticulum II Dwarf Spheroidal Galaxy}",   journal = {\apjl}, archivePrefix = "arXiv",    eprint = {1504.03309},  primaryClass = "astro-ph.HE",  keywords = {dark matter, galaxies: dwarf, galaxies: individual: Reticulum II, gamma rays: galaxies, methods: statistical, stars: kinematics and dynamics},      year = 2015,     month = aug,    volume = 808,       eid = {L36},     pages = {L36},       doi = {10.1088/2041-8205/808/2/L36},    adsurl = {http://adsabs.harvard.edu/abs/2015ApJ...808L..36B},   adsnote = {Provided by the SAO/NASA Astrophysics Data System} }   and corresponding bbl file giving the error at compilation is  \bibitem{2009ApJ...697.1071A} {\sc W.~B. {Atwood}, A.~A. {Abdo}, M.~{Ackermann}, W.~{Althouse},   B.~{Anderson}, M.~{Axelsson}, L.~{Baldini}, J.~{Ballet}, D.~L. {Band},   G.~{Barbiellini}, and et~al.} \newblock {\bf {The Large Area Telescope on the Fermi Gamma-Ray Space Telescope   Mission}}. \newblock {\em \apj}, {\bf 697}:1071--1102, June 2009.   My guess is that Kile doesn't like references of the form 2015ApJ...808L..36B since these are the only ones giving the error.    Can somebody hint me to the problem in this? Thank you very much I have a list/queue of 200 commands that I need to run in a shell on a Linux server.   I only want to have a maximum of 10 processes running (from the queue) at once. Some processes will take a few seconds to complete, other processes will take much longer.   When a process finishes I want the next command to be "popped" from the queue and executed.  Does anyone have code to solve this problem?  Further elaboration:  There's 200 pieces of work that need to be done, in a queue of some sort. I want to have at most 10 pieces of work going on at once. When a thread finishes a piece of work it should ask the queue for the next piece of work. If there's no more work in the queue, the thread should die. When all the threads have died it means all the work has been done.  The actual problem I'm trying to solve is using imapsync to synchronize 200 mailboxes from an old mail server to a new mail server. Some users have large mailboxes and take a long time tto sync, others have very small mailboxes and sync quickly. Here is a question from my number theory class.  Prove  $$(p-k)!(k-1)!\equiv (-1)^k \text{ mod p} $$ Help please! After using the simple LM317 on breadboard variable power supply for a while, a need for a more rugged and reliable bench power supply has arose.    Short on money, i decided to build it as many other amateurs like me did. The thing is that, for my current needs i don't need a giant digitally controlled multi-channel 500 watt beast or something like that.  Instead what i really want is a low wattage positive and negative low voltage ouput -12v-0v-12v for example. However i really like that my power supply to be safe, reliable and fool-proof as far as possible. So after searching the web here and there, i found many designs that from my point of view fell in one of two divisions:-   Ones that use discrete op-amps and transistors. And ones that use integrated voltage regulators.   So -at least for me- i think that the ones with discrete op-amps and transistors are more prone to malfunctions and issues compared to the integrated ones with all of their internal over current and thermal protection circuits which would need to be discretely implemented in the bench power supplies that utilize discrete op-amps, however those designs have the advantage of ease of customization and more importantly that it is easier to have 0V output compared to 1.2V in integrated voltage regulator ones.    So i like advice to help me choose between circuits that utilize discrete op-amps like this circuit for example:-  Or ones that use integrated voltage regulators with their intrinsic robustness and low form factor.    Also as a side but related question i have seen many designs on the web that utilize negative voltage fed to the adjust or like pins to achieve 0V output from integrated voltage regulators like this single positive power supply:-     Or a positive and negative channels power supply that i really like its design because of simplicity (not because of laziness but to avoid the drawbacks that may come with complex designs especially when implemented by an amateur like me):- And the question is      Is it wrong or a system safety and reliability lowering act to feed negative voltage to adjust pin for LM317 for example?     I ask this question because the datasheet clearly states that the working output range is 1.2V-37V for LM317 for example, also no similar circuit is mentioned in the Typical Applications section except for the following one:- And even in that circuit, however the adjust pin is tied to the negative rail, it does't regulate during this interval instead it is shut until the next half wave at least that what i understand.    So at last to sum it up which alternative is best suited for my needs, its pros and cons and suggested circuits if possible. "need not to be neither atomic nor ordered" Is this double/triple negative grammatically sound?  Ordered operations require that space on disk is allocated sequentially, so spatial ordering corresponds to chronology of operations, but actual disk writes need not to be neither atomic nor ordered.   Explanation:   Words neither and nor emphasize on the fact that both conditions are (independently) allowed to remain unsatisfied, that both are optional. To be more formal, "need not be atomic and need not be ordered". But then again, it becomes a concoction of two negations joined by a conjunction. $f$ strictly increasing does not imply $f'>0$ We know that a function $f: [a,b] \to \mathbb{R}$ continuous on $[a,b]$ and differentiable on $(a,b)$, and if $f'&gt;0 \mbox{ on} (a,b)$ , f is strictly increasing on $[a,b]$. Is there any counterexample that shows the converse fails?   I have been trying to come up with simple examples but they all involve functions that are discontinuous or has derivative $f'=0$ which does not agree with the hypothesis hmmm If a subring of a ring R has identity, does R also have the identity? I know it does not make sense that if a subring of a ring $R$ is commutative, then $R$ is also commutative. (For example, the set consisting of the matrices whose all entries except (1,1)-entry are zero, is a subring of ring of 2x2 real matrices.)  I also considered the case of a ring containing a subring with identity, but I had no ideas. Maybe it seems that it does not make sense, either.  Who give me some examples supporting my guess? Text spirals with TikZ I just ran across this, and I'm curious about whether it can be replicated in TeX...    Ideally one would have the spiral getting tighter and tighter as one got to the centre, as in    I know TikZ has the ability to fit text along a path, but I'm not sure how one might make text get smaller and smaller.  The closest I can find is , but that uses manually inserted font commands.  Edit: I got what I wanted using mwibrow's answer: Running junit tests in parallel in a Maven build? I'm using JUnit 4.4 and Maven and I have a large number of long-running integration tests.  When it comes to parallelizing test suites there are a few solutions that allow me to run each test method in a single test-class in parallel. But all of these require that I change the tests in one way or another.  I really think it would be a much cleaner solution to run X different test classes in X threads in parallel. I have hundreds of tests so I don't really care about threading individual test-classes.  Is there any way to do this? Constant Amortized Time What is meant by "Constant Amortized Time" when talking about time complexity of an algorithm? In plain English, how does casting spells and using creature abilities work with the stack and priority? Within 300 km of Tokyo: Where for flora, landscape, nature? I plan to visit Japan for 10 days and apportion 5 days to Tokyo. For the remainder, I want to escape the megalopolis and enjoy picturesque backwoods or countryside. Please recommend? Criteria:   No dangerous animals or untamed boondocks. No  or snakes. I won't drive, and must rely on public transport and walking less than 5 km in total.  No shrines, temples or any religious edifice. OPTIONAL: I fancy  , the more  the better.   This instantiates, doesn't duplicate, . Prove that $ m_{a} \geq m_{g} \geq m_{h} $ using strict inequalities unless $ a = b $. $ m_{a} = \frac{1}{2} (a + b) $   $ m_{g} =  \sqrt{ab} $   $ \frac{1}{m_{h}} = \frac{1}{2}(\frac{1}{a} + \frac{1}{b})$   Attempted Solution:  I believe I have shown the first step, which is $ m_{a} \geq m_{g} $ but i'm stuck on showing $ m_{g} \geq m_{h} $  $ \frac{a + b}{2} &gt; \sqrt{ab} $  $ (\frac{a + b}{2})^2 &gt; (\sqrt{ab})^2 $  $\frac{a^2 + 2ab + b^2}{4} &gt; ab$  $a^2 + 2ab + b^2 &gt; 4ab $  $a^2 -2ab + b^2 &gt; 0 $  $(a - b)^2 &gt; 0 $   so if $a = b$ we have $(a -b)^2 \geq 0$  Therefore, $m_{a} \geq m_{g} $  Now, i'm not sure if that is correct or not, if not can you please guide me to the complete solution or if I am correct on this part, provide a solution for $m_{g} \geq m_{h} $ Array slices in C# How do you do it? Given a byte array:  byte[] foo = new byte[4096];   How would I get the first x bytes of the array as a separate array? (Specifically, I need it as an IEnumerable&lt;byte&gt;)  This is for working with Sockets. I figure the easiest way would be array slicing, similar to Perls syntax:  @bar = @foo[0..40];   Which would return the first 41 elements into the @bar array. Is there something in C# that I'm just missing, or is there some other thing I should be doing?  LINQ is an option for me (.NET 3.5), if that helps any. My mortgage came up for renewal right at the time in 2009 when UK interest rates hit rock bottom. This was unprecidented, and most financial advice was to take out a fixed-rate mortgage. So I perhaps went overboard and got one for ten years.  Five years on, interest rates haven't moved and I'm losing money on it to the tune of £100 a month. Obviously, this is ongoing: so that decision has cost me about £5000 in real terms so far. It'll come to a lot more by the end of the mortgage, unless interest rates rise.  Being fixed rate, it's been designed so you can't get out early. If I decide to end the mortage, it'll cost me £1,000 per year of the mortgage remaining - which is roughly what I'm losing anyway, so that seems a bad idea.   I can overpay by up to £500 per month. However, doing this doesn't help pay down the mortgage at all: the total is just added up and will cause the mortgage to end early, by a period dependent on the overpayment total.   This seems to me to be a very bad idea because hoping interest rates rise over the next five years is the only hope I have of making good on some of the losses that I've made.   Is this sensible thinking? If so, is there anything at all I can do to try and ameliorate the financial pain this product is causing me?