How to apply polymorphic function on vector of subclasses
What is object slicing?
How to get distance when acceleration is not constant? How to find out when an Oracle table was updated the last time What is the typical orbital life of an artificial satellite? The orbit of satellites around Earth eventually decays, or so I read. This is typically caused either by atmospheric drag, or by tides. I would assume most satellites have a limited service life in orbit. Hence the question - What is the typical orbital life of a satellite? How long before it's successor must be launched into orbit ?  EDIT: For instance, a weather satellite Cleaning PCBs... using water? I found  where a technician with a lot of experience seems to clean his PCBs using water, and then he just puts it in the sun so it can dry. I was just amazed to see the circuit keeps working as intended, he says he keeps doing this all the time and several times, however I doubt this is normal.  Which leave me some questions:   What are the recommended methods to clean huge PCBs like the one in the video? What happens to charged capacitors when water shorts them out? Solder joints do not get any kind of corrosion? Is the antisolder mask waterproof? I'm using pdfLatex (with --shell-escape option) and I had a problem of compilation with TexWorks that was successfully solved with the help of other post in this site: .  After correcting that error the code compiles smoothly but just displays the logarithmic grids, not the function. The gnuplot files are created in the right place, but the graphic doesn't come out in the PDF.  Code from :  \documentclass{article}  \usepackage{tikz} \usepackage{bodegraph}  \begin{document}  \begin{tikzpicture}[     gnuplot def/.append style={prefix={}}, % Fixed the issue (prefix was 'gnuplot/\jobname/' before) ] \begin{scope} \UnitedB \semilog{-1}{2}{-50}{60}  \BodeAmp{-1:1.35}{\POAmpAsymp{4}{2.0}+\IntAmp{1}}  \end{scope} \end{tikzpicture} \end{document}   Any clues? In the early '80s, I read a story about a Terran man on another planet, where the natives develop skin lesions and eventually die, but are happy, as they become part of the planet they live on. I remember that the protagonist is not developing the lesions, because he hates the planet. Once he starts loving the planet, he starts having the lesions as well. In this story, the planet is "alive".  I have read about "" and "". They do not match my memory. Thank you. Accessing class members on a NULL pointer How to assign from a function which returns more than one value? How does the "this" keyword work? I use 'Helvetica' as my font and build my document using Texmaker. But the PDF generated has jagged edges while using this font and when I use a different font (say Times or even Helvetica sans-serif) it builds just fine.     Please suggest if there is anyway I can get over this. The problem with these jagged edges is that it appears very dull and unreadable at 100% resolution.  OK guys, now here is the MWE  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% HEADER %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \documentclass[a4paper,twoside,12pt]{book}  %% Language %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \usepackage[T1]{fontenc} \usepackage[latin1]{inputenc} %\usepackage[utf8]{inputenc} \usepackage{graphicx,color,subfigure}  %% Line Spacing %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \usepackage{setspace} %\singlespacing        %% 1-spacing (default) %\onehalfspacing       %% 1,5-spacing \doublespacing        %% 2-spacing  %% Other Packages %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \usepackage[left=1.5in, right=1.5in, top=1in, bottom=1in, includefoot, headheight=13.6pt]{geometry} \usepackage[pagebackref=true,breaklinks=true,letterpaper=true,colorlinks,bookmarks=false]{hyperref} \usepackage{helvet} \usepackage[square,numbers]{natbib} \usepackage{hyphenat} \usepackage{fancyhdr}   \begin{document}  \pagestyle{empty} %No headings for the first pages.  \cleardoublepage %The first chapter should start on an odd page.  \pagestyle{plain} %Now display headings: headings / fancy / ...  \pagebreak  %------------------------------------------------------------------------ \chapter{Divorce}   A major change that has occurred in the Western family is an increased incidence in divorce. Whereas in the past, divorce was a relatively rare occurrence, in recent times it has become quite commonplace. This change is borne out clearly in census figures. For example thirty years ago in Australia, only one marriage in ten ended in divorce; nowadays the figure is more than one in three (Australian Bureau of Statistics, 1996: p.45). A consequence of this change has been a substantial increase in the number of single parent families and the attendant problems that this brings (Kilmartin, 1997).   \end{document} "A/An" preceding a parenthetical statement Fluid filled harmonic oscillator A vessel (preferably circular) filled with water is accelerating unidirectionally such that the level of water is higher on one end than the other. What I want to know is that if the vessel is immediately stopped, the water level will force itself back to the equilibrium point, but in doing so push the other end up. If water is an ideal fluid, what type of oscillation will occur in this situation.   I can tell that maybe the mathematical expression for this oscillation will be complex, but please do let me know if I am thinking this correctly.   I am considering, finding the oscillation equation for infinitesimally small u-tubes(considering a 2-d plane) and integrating it to get the final expression.  Thanks in advance Has a movie from a movie series ever been removed/retconned due to fan/general outcry? A petition to strike the events of  from the main Star Wars timeline that is going around online has made me wonder if there has ever been a retcon/removal of a movie from a movie series or just renunciation of a movie by those with creative control due to backlash, as opposed to the director(s) just deciding to go a new direction/starting fresh. Google just produces said petition when searching (please note this is not for or against Star Wars).  Addendum, by removal I am referring to the events in the movie no longer being recognized in the universe. Just installed Ubuntu 17.10 and it seems that the keyboard layout switching has changed its behavior.  In the previous version of Ubuntu (such as 16.04 Unity), if I have 3 different keyboard layouts (for example EN-TH-JA), hitting Super+Space would always cycle to the next layout in the same order (e.g. EN to TH to JA then back to EN).  However since Ubuntu 17.10, this is no longer the case. It cycles through the layout in the MRU (Most Recently Used) ordering. So suppose that the layout starts with EN, then I cycled to TH. Next time I hit Super+Space, it would give me EN instead of JA.   I tried to dig up and found that the culprit is the newly implemented DCONF settings inside org.gnome.desktop.input-sources and there seems to be no way to change this behavior.   So my question is: Is there a way to change this behavior to "static ordering" of keyboard layout switching?    (As a side-note, the new behavior is very bad when we have three or more layouts. Most of the time we as a user couldn't remember the MRU layouts, so layout switching is very inconvenient and much slower than already knowing what the next layout would be if static ordering is used.)  If there is no settings to change this behavior, where should I report this as a bug or a feature request? Is there any way to have BibTeX or biblatex insert a bibliography without having citations in the body of the document itself? Maybe a way to hide the in-text citations, so that BibTeX still sees them and includes them in the bibliography, but does not print them in the body? How does Meta Stack Exchange work? Meta Stack Exchange seems to have different rules and user behavior than the "regular" Stack Exchange sites.  How is it different?    Individual questions answered below:                Related Can't download any app from AppStore! I'm using iPhone 6s 16 GB. My storage isn't full but still I can't download anything. Every time I wanted to start a download it keeps telling:  app name* could not be download at this time Why does resistivity increase with temperature?  The explanations I have heard so far are that increasing temperature increases vibrations in the lattice structure resulting in the number of collisions increasing.  But the vibrations from thermal energy are random, so around half of the vibrations would result in the atoms moving out of the electrons way and half would result in atoms moving into the way of the electrons.  And since half of the vibrations result in increasing the drift speed and half reduce it, shouldn't the average drift speed remain the same? Using the Fitch system, how do I prove $((p \implies q) \implies p)\implies p$? Using the Fitch system, how do I prove $((p \implies q) \implies p)\implies p$? I started with the hypotheses $(p \implies q) \implies p$ and $\sim p$. However, from these hypotheses I did not get the desired contradiction to solve the question.  Thanks sb45 Add sort by relevance to search jobs In Careers 2.0, individuals can choose "search jobs" and sort by date posted, job title, and company name.  However, Careers 2.0 already knows what tags I'm proficient in, and knows the tags associated with the job postings.  A sort option, relevance, should be added so that jobs matching my skill set, as demonstrated on stack exchange, will float to the top.