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I regularly find sites that copy content from elsewhere (mailing lists, etc) while not providing any added value. Quite to the contrary, they are pretty heaped with ads.  I'd like to remove those sites as permanently as possible from my Google search results. Any ideas? How to best encapsulate monetary values in a database Why is Newton's first law necessary? Newton's second law says $F=ma$. Now if we put $F=0$ we get $a=0$ which is Newton's first law. So why do we need Newton's first law ?   Before asking I did some searching and I got this: Newtons first law is necessary to define inertial reference frame on which the second law can be applied.  But why can't we just use Newton's second law to define an inertial frame? So if $F=0$ but $a$ is not equal to 0 (or vice versa), the frame is non-inertial.  One can say (can one?) we cannot apply the second law to define a reference frame because it is only applicable to inertial frames. Thus unless we know in advance that a frame is inertial, we can't apply the second law.  But then why this is not the problem for the first law?  We don't need to know it in advance about the frame of reference to apply the first law. Because we take the first law as definition of an inertial reference frame.  Similarly if we take the second law as the definition of an inertial frame, it should not be necessary to know whether the frame is inertial or not to apply the second law (to check that the frame is inertial). Auto-fit TextView for Android Let $X,Y$ be topological and $f:X \to Y$ be open and continuos.  I am studying Baire space and I would like to try the following facts :      $(i)$ The inverse image of dense set is dense.       $(ii)$ The inverse image of comeager set is comeager.   I am studying Baire space and I would like to try the following facts  Can we collaborate to verify the above claims?    Thanks. What determines whether colors you can't see are visible or not? So, when someone is red-green colorblind, the colors appear the same to them, like this:   And if you're totally colorblind, then things presumably just appear like they would in a black-and-white movie.  However, this isn't how ultraviolet patterns seem to work. Compare how we see this flower to the version where ultraviolet is visible:   The UV pattern is completely invisible here. However, unlike with the red and green, this isn't because yellow and UV are colors that appear identical when you can't see UV. Look at these flowers:     This time the flowers are purple, but the UV pattern is still invisible. Why is that? Shouldn't the UV pattern still be apparent on at least one of the flowers, just in a different color? And on some other flowers, the UV does appear as a different color. So:    Why is the UV invisible only sometimes?  Does it have to do with the flower using iridescent structures to produce color, instead of a pigment? Can this happen with red and green, as well? When a user who approved an edit is removed, an incorrect "-2 reverted" event appears in reputation history I am aware that . But now there is an extraneous "reverted" event to go along with user removal:     Source: .   The edit was not reverted, it's . In any case, I should not lose 2 points twice for the total of -4. And indeed, my reputation only dropped from 131 to 129 despite what the history suggests.   So the line with "-2 reverted" is a bug.     A more extreme example:  got 21 "reverted" events on 2017-06-30, none of which should be there. His rep loss is 42, not 84 as the reputation history says. I have Dubai work permit mailed to me by my employer. It contains my old passport number which has ECR stamp. I then got a new passport issued without ECR stamping, but with different passport number. I have both passports.  Can I travel to Dubai now? I am trying to follow the  and . I tried to push some of my Lightning components which depend on a managed package in App Exchange. I would like to know how to install a managed package using Salsforce DX CLI so that i can use that command in my travis.YML file for my CI integration.  Here is the script for my Travis file  sudo: true dist: trusty cache: false env: - URL=https://developer.salesforce.com/media/salesforce-cli/sfdx-linux- amd64.tar.xz before_install:  - export SFDX_AUTOUPDATE_DISABLE=true - export SFDX_USE_GENERIC_UNIX_KEYCHAIN=true - export SFDX_DOMAIN_RETRY=300 - wget -qO- $URL | tar xJf - - "./sfdx/install" - export PATH=./sfdx/$(pwd):$PATH - sfdx update - sfdx force:auth:jwt:grant --clientid $CONSUMERKEY --jwtkeyfile  assets/server.key --username $USERNAME --setdefaultdevhubusername -a DevHub script: - sfdx force:org:create -f config/project-scratch-def.json -s -a  PackageInstallation - sfdx force:org:list - sfdx force:org:display - sfdx force:user:password:generate -u PackageInstallation - sfdx force:org:display - sfdx force:org:open -u PackageInstallation - sfdx force:source:push -u PackageInstallation - sfdx force:apex:test:run -u PackageInstallation -c -r human   I get the following error as my components depend on the app exchange components:     No COMPONENT named markup://ldt:datatableDev found : Profile changes in Q&A are not pushed to Area 51 I just noticed that the info text on  is an older version of the text in .  I found  from April 2016 where Adam Lear says:     Area 51 is a separate codebase. It's also heavily outdated. Currently we can push a profile update from Q&amp;A to Area 51, but not the other way around   I think the pushing isn't working anymore. I just updated my text on SO again and it was changed in all my accounts, except Area 51. Given any uncountable subset $S$ of the unit interval. Then $S$ clearly has an accumulation point and indeed uncountably many (which might also be a nice exercise). So my question is: Is there an accumulation point, that again lies in $S$? JavaScript closure inside loops – simple practical example I own a Nikon D40X and just the kit lens and I'm considering buying either a macro lens or some extension tubes.  I don't necessarily want to do true 1:1 macro, just some close ups of bugs, fungi and flowers. I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it. wrong positioning of figure with tabular in xelatex I recently updated MikTex and it seems Xelatex is not able to place figures correctly anymore. Before updating all figures were shown correctly. I work with Texworks and Miktex 2.9  Here it is the code that I run:  \documentclass[10pt,a4paper]{report} \usepackage{graphicx} \graphicspath{{method1/}{method2/}{dpfig/}}  \begin{document}  \begin{figure}[!htbp] \centering \begin{tabular}{cc} \includegraphics[trim=6cm 2.5cm 6cm 2.5cm,clip=true,width=0.33\textwidth]{figure1.eps}&amp; \includegraphics[trim=6cm 2.5cm 6cm 2.5cm,clip=true,width=0.33\textwidth]{figure2.eps}\\ \end{tabular} \caption{Two figures} \end{figure} \end{document} \end{figure}   With this code, figures are correctly trimmed and the relative position between figure 1 and figure 2 is maintained. However, the position in the document is wrong: figure are placed upper and more right than expected (as the bottom-left corner of the table was placed in the middle of the page). The unusual thing is that this does not happen in draft mode and picture are shown centered as it would be.  I usually compile with Xelatex, Makeindex and Bibtex.  I hope to have been clear.. bye!  EDIT: Sorry, I forgot to add the images I prepared from the file that run that script: Sums and products of algebraic numbers How does one go about proving that the sums and products of two algebraic numbers over a field $F$ (say $a,b\in K$, where $K/F$ is a field extension) is also algebraic?   If we call $f_a$ and $f_b$ the min. poly's of $a$ and $b$, then I'm assuming the answer involves such polynomials. Perhaps looking at their roots in splitting fields for both of them? And finding a "big" splitting field, constructed from those two other ones?      In particular, I'd like a way of explicitly constructing the minimal polynomials $\ f_{ab}$ of $ab$ and $f_{a+b}$ of $a+b$.     I read somewhere that $g(x)=\Pi_j\Pi_i (x-\alpha_i\beta_j)$ works for $ab$, where the $\alpha_i$ and $\beta_j$ are the roots of $f_a$ and $f_b$, respectively, but I do not know why $g(x)\in F[x]$.  Similar remarks for $a+b$ How do I get powdered mammoth tusk? Am I missing something? I can find plenty of tusks, but I just don't know if I can make them into powder myself or do I have to find them for sale? How to say that you have plans to go to the movies tonight (but you are not sure yet, maybe you will have a pizza)? I mean there are options:     I am going to the cinema tonight.   Way too much certainty in this. For me it means that you have already bought tickets, the least.     I am going to go to the cinema tonight.   Sounds a bit awkward.     I will go to the cinema tonight.   Sounds too formal to me. Module 'pdftexcmds' not found after update Yesterday I updated my distribution (tlmgr update --all) and now I cannot use TikZ with lualatex anymore.  Minimal working example:  \documentclass{article} \usepackage{tikz} \begin{document} a \end{document}   Compilation output:  &gt; lualatex a This is LuaTeX, Version 1.10.0 (TeX Live 2019)                                                                                                                                                                         restricted system commands enabled.                                                                                                                                                                                  (./a.tex                                                                                                                                                                                                              LaTeX2e &lt;2019-10-01&gt; patch level 3                                                                                                                                                                                     luaotfload | main : initialization completed in 0.098 seconds                                                                                                                                                         (/opt/texlive/2019/texmf-dist/tex/latex/base/article.cls                                                                                                                                                              Document Class: article 2019/10/25 v1.4k Standard LaTeX document class                                                                                                                                                (/opt/texlive/2019/texmf-dist/tex/latex/base/size10.clo))                                                                                                                                                             (/opt/texlive/2019/texmf-dist/tex/latex/pgf/frontendlayer/tikz.sty                                                                                                                                                    (/opt/texlive/2019/texmf-dist/tex/latex/pgf/basiclayer/pgf.sty                                                                                                                                                        (/opt/texlive/2019/texmf-dist/tex/latex/pgf/utilities/pgfrcs.sty              ...  (/opt/texlive/2019/texmf-dist/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex (/opt/texlive/2019/texmf-dist/tex/generic/pgf/libraries/pgflibraryplothandlers. code.tex) (/opt/texlive/2019/texmf-dist/tex/generic/pgf/modules/pgfmodulematrix.code.tex)  (/opt/texlive/2019/texmf-dist/tex/generic/pgf/frontendlayer/tikz/libraries/tikz librarytopaths.code.tex))) No file a.aux. ABD: EveryShipout initializing macros (/opt/texlive/2019/texmf-dist/tex/context/base/mkii/supp-pdf.mkii [Loading MPS to PDF converter (version 2006.09.02).] ) (/opt/texlive/2019/texmf-dist/tex/latex/epstopdf-pkg/epstopdf-base.sty[\direc tlua]:1: module 'pdftexcmds' not found:         no field package.preload['pdftexcmds']         [kpse lua searcher] file not found: 'pdftexcmds'         [kpse C searcher] file not found: 'pdftexcmds' stack traceback:         [C]: in function 'require'         [\directlua]:1: in main chunk. l.165       \directlua{require("pdftexcmds")}  ?    It seems that a Lua package is missing.  Is this a bug? Am I missing a package? Using Boolean parameters in Python Script Tool of ArcPy? I'm using ArcGIS for Desktop 10.3.0.4322 I have a script tool which requires a parameter (folder path to a gdB, via GetParameterAsText) so that a later process can be saved there. The thing I want to do is make an Optional Boolean parameter, that when checked, automatically fills in the folder path gdB parameter. The Boolean text asks the user, &quot;Use default workspace?&quot;, to which if they check the box (boolean == True), then the folder path parameter will be automatically defaulted (saving the user a small amount of time). I have already created the Boolean parameter in the script tool, I am however unaware of how to &quot;fill in&quot; the required parameter based on the user's Boolean. Code Snippet: # Ask user to select the Geodatabase workspace to use for data output userWorkspace = arcpy.GetParameterAsText(0)  # Ask user if they want to use default workspace (boolean) useDefault = arcpy.GetParameterAsText(1)  # If user wants default workspace, then give it to the required parameter (0) if useDefault == True:  arcpy.env.workspace = path else:  # Set workspace environment based upon user's choice  arcpy.env.workspace = userWorkspace