Black spot on image while shooting with high aperture
Why are these black dots / spots appearing in my pictures?
If I have a legendary creature out, and I make a copy of it (such as by enchanting it with  or making a ), do I get enters-the-battlefield effects from the creature before I have to sacrifice it to the legend rule? How to Merge columns in crystal report How can I add certain mobs to a team and make them passive to me if they would normally attack me? I know how to do it in 1.8, but how can I do it now in 1.16.4? Quantum Hall effect for dummies In the past few days I've become increasingly intrigued by the QHE, mainly thanks to very interesting questions and answers that have appeared here. Unfortunately, I am as of yet very confused by all the (seemingly disparate) stuff I learned.  First, here are some random points that I've been able to gather   I(nteger)QHE occurs due to the presence of Landau levels IQHE is an embodiment of topological order and the states are characterized by the Chern number that tells us about topologically inequivalent Hamiltonians defined on the Brillouin zone IQHE requires negligible electron-electron interations and so is dependent on the presence of impurities that shield from Coulomb force F(ractional)QHE occurs because of formation of anyons. In this case Coulomb interaction can't be neglected but it turns out an effective non-interacting description emerges with particles obeying parastatistics and having fractional charge FQHE has again something to do with topology, TQFT, Chern-Simons theory, braiding groups and lots of other stuff FQHE has something to do with hierarchy states   So, here are the questions        Most importantly, do these points make sense? Please correct any mistakes I made and/or fill in other important observations   How do explanations 1. and 2. of IQHE come together? Landau quantization only talks about electron states while topological picture doesn't mention them at all (they should be replaced by global topological states that are stable w.r.t. perturbations)   How do explanations 4., 5. and 6. relate together   Is there any accessible introductory literature into these matters?   Do IQHE and FQHE have anything (besides last three letters) in common so that e.g. IQHE can be treated as a special case? My understanding (based on 3.) is that this is not the case but several points hint into opposite direction. That's also why I ask about both QHE in a single question How can I get to Iceland on a cargo ship? Planning a low budget and environment friendly trip to Iceland from Helsinki, Finland next summer for me and my friend. Haven't been able to find relevant information on possibility for cargo travel (from where - eg. Norway, Denmark? - timetables, prices etc). Expected departure from Helsinki around June 18th, return at latest on July 7th 2015. I'm very thankful for any related advice (and first time on stackexchange, so apologies if I didn't formulate my question in a best possible way) How can I query the  for tags I've created? I have a question about the following problem from a Putnam review:  Let $n\in \mathbb{N}$. Find how many pairs of natural numbers $(x, y)\in \mathbb{N}\times \mathbb{N}$ solve $$ \frac{xy}{x+y}=n. $$  I have found some solutions for all $n$, such as $(2n, 2n)$ and $(n+1, n(n+1))$, but I feel as though this is the wrong approach, as the question is only asking for the number of solutions to the equation.  I don't really want a complete solution, but any hints would be greatly appreciated. Of course preventing them from getting stolen is the top priority, but invariably, someone is going to get jacked. What are some good practices to minimize the damage incurred when your PC is stolen?  Given most of our PCs contain our entire lives, its frightening to know that all this information can be in someone else's hands.   Some ideas i had (a bit paranoid, i admit).   keep encrypted backups.  Use truecrypt to have double encrypted (with strong password) volumes where you store your personal data. schedule Eraser to run every evening so that potential thieves couldn't undelete (and subsequently retrieve) sensitive data do all your banking in a virtual machine.  Keep the virtual machine volume encrypted, and on a portable usb drive that you carry with you / keep in a safe. have applications that phone home (or hit something to leave an IP trace) upon connection to the internet (can someone suggest a good solution for this?)   Does anyone have any other suggestions? My random variable $X$ is normally distributed with mean $b$ and variance $p$. I defined a new RV, $Y$, such that $Y=1/X$. Does anyone know how to find the mean of $Y$ and $Y^2$? Example of the equality of an inequality This question is related to Daniel Fischer's answer . Suppose $f$ is a real $C^{1}$ function on $[0, 1]$ such that $f(0) = 0$ and $\int_{0}^{1}f'(x)^{2}\, dx \leq 1$. Then (essentially by Cauchy-Schwarz), we have $\left|\int_{0}^{1}f(x)\, dx\right| \leq 2/3$ as Daniel Fischer stated in his answer.  My question is: Is there an example of a function such that we have equality in $\left|\int_{0}^{1}f(x)\, dx\right| \leq 2/3$? I was thinking of maybe a smoothed version of a function which takes the value $0$ on $[0, 1/2)$ and $4/3$ on $(1/2, 1]$ but that seems complicated to construct, moreover, the derivative in some neighbourhood of $1/2$ might be hard to control. Why is my SSH login slow? I'm seeing delays in SSH Logins. Specifically, there are 2 spots where I see a range from instantaneous to multi-second delays.   Between issuing the ssh command and getting a login prompt and between entering the passphrase and having the shell load   Now, specifically I'm looking at ssh details only here. Obviously network latency, speed of the hardware and OSes involved, complex login scripts, etc can cause delays.  For context I ssh to a vast multitude of linux distributions and some Solaris hosts using mostly Ubuntu, CentOS, and MacOS X as my client systems.  Almost all of the time, the ssh server configuration is unchanged from the OS's default settings.  What ssh server configurations should I be interested in?  Are there OS/kernel parameters that can be tuned? Login shell tricks?  Etc? Can I permanently block an update (non-driver) that will not install on my machine on Win10 pro? I have an update to Visual Studio 2010 that will NOT update and has failed hundreds of times. Manually installing it also fails, and no source has been found for manually getting this very old patch to install on Windows 10. I believe the problem is that Microsoft simply hasn't re-tested KB2890573 at all and it doesn't install on Win10 ver 1511 at all, anymore.  I do not want to use the MS utility that will postpone this update for a while. I want to permanently block it so it does not appear in the windows update list ever again. Convert a JSON string to object in Java ME? Let $F$ be a field. Why does $F[x]$ have infinitely many irreducible elements?   For the case F has characteristic 0  Then x-a is irreducible for all a $\in F$ since x satisfies no non-trivial relations in F.  Obviously this argument fails for a finite field since there are only finitely many a to choose from.  So how may I construct irreducible polynomials in a finite field?  I figure it must involve higher powers of x, maybe $x^n-a$ ? PHP function overloading I wonder about the foundations of set theory and my question can be stated in some related forms:   If we base Zermelo–Fraenkel set theory on first order logic, does that mean first order logic is not allowed to contain the notion of sets? The axioms of Zermelo–Fraenkel set theory seem to already expect the notion of a set to be defined. Is there are pre-definition of what we are dealing with? And where? In set theory, if a function is defined as a set using tuples, why or how does first order logic and the axioms of Zermelo–Fraenkel set theory contain parameter dependend properties $\psi(u_1,u_2,q,...)$, which basically are functions? How can I recover a game center account where I forgot ID and password? A long time ago, I made a game center account to which I attached my CoC village. This account hasn't been used anymore, and I have forgotten the ID and the password.  Now I want to transfer that game to my new phone which has a new game center ID, but need a transfer code from the old account to do so. Is there a way to recover my old game center account details? How to remove Open CTI VF softphone page from salesforce left side Open CTI Softphone VF page is showing in salesforce left side. How to remove this ? Screenshot attached What can i put into \setmathfont{&lt;...&gt;.otf} for the unicode-math package to make it all work (with XeLaTeX or LuaLaTeX)?  There are several suggestions on the  of unicode-math, but the first option is commercial, and the second and the third do not work with the following example:  % !TEX TS-program = xelatex  \documentclass{article} \usepackage{unicode-math} \setmathfont{latinmodern-math.otf} % \setmathfont{texgyrepagella-math.otf} % \setmathfont{xits-math.otf}  \begin{document} $X\setminus Y$ \end{document}   I do not get the \setminus character in the output.  The \setminus character is also missing if i do not set a math font at all (i do not know which font is used in this case).  It works with xits-math, but i do not like it.  Is it expected by the way that the \setminus character is left blank without giving any warning? Mining cryptocurrencies with Ubuntu and sgminer What are the steps for setting up a Ubuntu machine for mining of crypto-currencies?  I am looking for a full guide to follow - from installing Ubuntu to how to config and start the miner itself.