Software to block specific internet web pages I am looking to download some software on an old laptop that runs the Ubuntu Operating System on it.  The software that I am interested in is something that will allow me to block specific internet web pages.  Does anyone know of any such software for the Ubuntu system?
What is the best way to restrict access to adult content? I bought my kids a PC and installed 12.04 (Unity) on it.  The bottom line is, I want my children to use the computer unsupervised while I have confidence they cannot access anything inappropriate.  What I have looked at:  I was looking at Scrubit a tool which allows me configure my wifi router to block content and this solution would also protect my other PC and mobile devices.  This may be overkill as I just want the solution to work on one PC.    I also did some Google searches and came across the application called .  My experience of OSS is that the best solutions frequently never appear first on a Google search list and in this case I need to trust the methods therefore my question is very specific.   I want to leverage your knowledge and experience to understand What is the best way to restrict adult content on 12.04 LTS as this is important to me.  It maybe a combination of things so please don't answer this question "try this or that", then give me some PPA unless you can share your experience of how good it is and of course if there are any constraints.
What is the evidence that dark energy exists? (as of 2020) Astrophysicists believe that dark energy exists and makes up ~70% of the universe's energy content. What is the evidence that dark energy exists? Wikipedia gives :   Supernovae. A specific type of supernovae (type 1A) are supposed to be standard candles - that is, their luminosity is known. In turn this lets us measure distance to faraway galaxies, check how fast those galaxies are receding from us, and check if that recession speed is increasing over time. CMB. Data from the Cosmic Microwave Background indicates the universe is approximately flat. Visible matter + dark matter can account for ~30% of the energy content required to make the universe flat, leaving ~70% for something else - dark energy. BAO. Baryon acoustic oscillations act as a "standard ruler" that lets us measure how the Hubble constant varies with redshift (i.e. time), and see if the recession speed is increasing with time. Late-time ISW. ISW stands for integrated Sachs-Wolfe effect. The idea is that, usually, a photon that enters a potential well gains energy as it falls in and loses energy as it emerges, and gain/loss exactly cancel. If a universe is expanding in accelerated fashion, then this is untrue; the potential wells / hills are smoothed out and there is a permanent shift in the photon's energy and therefore temperature. If we see a correlation between hot and cold spots on the CMB and the locations of superclusters and voids, then it's a sign of accelerated expansion. Galaxy evolution. This uses (known) evolution of early-type galaxies as a standard clock. Once we know how long it takes for a galaxy to evolve from one state to another, as well as their redshifts, we can reconstruct how the Hubble constant varies over time, and see if the recession speed is increasing with time.   Two questions:   Did I understand any of these five methods wrong? Are there any other lines of evidence for the existence of dark energy? Why is this CW post saying 36% unknown? Looking at         it says "36% unknown". No user by the name of 'unknown' appears in the  ()  What madness is this? Who is this 'unknown' you speak of? I heard using 'could' is for politeness. When I request something, should I say "Can you please" or "Could you please"? Does the latter sound over-polite and pretentious? What is the difference between a neural network and a deep neural network, and why do the deep ones work better? I haven't seen the question stated precisely in these terms, and this is why I make a new question.  What I am interested in knowing is not the definition of a neural network, but understanding the actual difference with a deep neural network.  For more context: I know what a neural network is and how backpropagation works. I know that a DNN must have multiple hidden layers. However, 10 years ago in class I learned that having several layers or one layer (not counting the input and output layers) was equivalent in terms of the functions a neural network is able to represent (see Cybenko's ), and that having more layers made it more complex to analyse without gain in performance. Obviously, that is not the case anymore.  I suppose, maybe wrongly, that the differences are in terms of training algorithm and properties rather than structure, and therefore I would really appreciate if the answer could underline the reasons that made the move to DNN possible (e.g. mathematical proof or randomly playing with networks?) and desirable (e.g. speed of convergence?) Inspired by this Hagon Von Eitzen's answer( ) I started investigating how I could express natural numbers as differences of squares. Using the method explained in the solution, I investigated natural numbers up to $60$ manually. I observed the following:  There is no way to express numbers of the form $4k+2$ as a difference of two squares.  2.There is one and only one way to express prime numbers (except $2$) as a difference of two squares.  The smallest number that can be expressed as a difference of two squares in two different ways is $15$ and the smallest number that can be expressed as a difference of two squares in three different ways is $45$.  As, $15= 8^2-7^2=4^2-1^2$. $45=23^2-22^2=9^2-6^2=7^2-2^2$. I could prove point $2$ easily but could not prove point $1$. Also I am interested in knowing how I could find the smallest natural number that could be expressed as a difference of two squares in four different ways without manual calculation. how to host multiple pages from diferent domains all together? How to check if a String contains another String in a case insensitive manner in Java? Record Animation In BGE How do I syntax check a Bash script without running it? Is it possible to check a bash script syntax without executing it?  Using Perl, I can run perl -c 'script name'. Is there any equivalent command for bash scripts? Are there philosophers who examined the reasons for believing in the existence of other people? While I am familiar with Descartes and the oft-quoted idea, I think therefore I am, I am not familiar with any philosophy that actively sought to rationalize that anybody else exists.  Are there philosophers who analyzed this question? Or is it taken for granted that it is (im)possible for anybody to validate their own existence to somebody else? Is anti-gravity (i.e. repulsive gravity) possible in theoretical physics? Is  (i.e. repulsive gravity) possible in string theory?  I have read some articles about scientists making assumptions about the existence of anti-gravity, but is it possible in string theory? Give a one-to-one and onto function from $\mathbb{N} \times \mathbb{N}$ to $\mathbb{N}$ How to avoiding losing your current browsers websites when being redirected by wireless login pages ST_Length (GEOM, true) for calculating distances in Geographic Reference System Windows 7 unidentified network (or limited access) after hibernate My windows 7 network will show limited access or unidentified network after coming up from hibernation.  In the office I normally use LAN connection, I turn-off my wireless card (DELL Latitude has on/off switch for the wireless card). When I back at home I will turn on the wireless card, but it will take about 15 seconds to detect my home WIFI and then show limited access. I will have to restart the notebook and it will be able to connect to my WIFI and internet.  The problem will be solved if I restart the notebook, but that defeats the purpose of hibernation doesn't it?  I have tried uninstalling the wireless card driver but still does not solve it. I also tried updating my network card driver but windows says I am using the latest driver. On support.dell.com also showing I am using the latest driver. A closed subset of an algebraic group which contains $e$ and is closed under taking products is a subgroup of $G$ A closed subset of an algebraic group which contains $e$ and is closed under taking products is a subgroup of $G$.   Denote this set as $X$. If the condition of $X$ being closed is dropped, this statement does not hold. The set of nonzero integers in $\mathbb{G}_m$ over $\mathbb{C}$ is a counterexample.  It suffice to prove that for any $x \in X$, $x^{-1}X = X$. As $X$ is closed under taking products, it is clear that $X \subseteq x^{-1}X$. In order to prove the inverse inclusion, the closedness of $X$ (under Zariski topology) must be used.   Let $\phi: G \rightarrow G, y \mapsto x^{-1}y$ is a homoemorphism of $G$ as an algebraic variety. So $x^{-1}X = \phi(X)$ is a closed subset of $G$ containing $X$. But Why are they equal?  Thanks very much. What does a de Broglie wave look like? What does a  wave look like? Are de Broglie waves transverse or longitudinal?   Can they be polarized?    What about the de Broglie wave of a ground state neutral spin-zero Helium 4 atom?   What experimental evidence do we have that supports the detailed nature of a de Broglie wave?     I have always assumed that de Broglie waves were mathematically  identical to electromagnetic waves, but I just realized there is no basis for this assumption, and in fact it must be false, unless there is an analogue to both the magnetic and the electric components of the electromagnetic wave.  So what does a de Broglie wave "look like"? I am trying to set up a wordpress multisite with MAMP Pro that will allow me to have two different domains (one domain for each language): dev.domainenglish.com dev.domainfrench.com I have already set up the primary english virtual host and secondary virtual french host. I have installed the wordpress multi site on the primary English virtual host. Next I created a &quot;sub site&quot; within the primary english domain multi site that has the location  dev.domainenglish.com/french/ Then I tried to use the MU Domain mapping plugin to make it so that when you visit dev.domainfrench.com the theme and content posted on dev.domainenglish.com/french/ will be visible. As of now when you visit dev.domainfrench.com the page loads the standard MAMP Pro index.html instead of my wordpress subsite:  the virtual host was set up successfully. If you can see this page, your new virtual host was set up successfully. Now, &gt;web contents can be added and this placeholder page1 should be replaced or &gt;deleted.&quot;  I understand that this plugin was built for live sites. But is there anyway I can achieve my goal of having two domains under one Wordpress multisite on my localhost? Thank you for your time! I am trying to restore a database with the following command:  $ sudo -u postgres pg_restore -C -d dvdrental dvdrental.tar  [sudo] password for t:    However, I am receiving the following error message:      could not change directory to "/home/t/mydata/.../relation model/SQL/implementations/Implementations, i.e. relational database management systems/postgreSQL/general/web/postgresqltutorial/databases": Permission denied      pg_restore: [archiver] could not open input file "dvdrental.tar": No such file or directory   I was wondering why I can't change directory to the current directory with permission denied?  File permission bits are:   -rw-rw-r-- 1 t t 2838016 May 26  2013 dvdrental.tar   Is it because one of its ancestry directory is not both readable and executable by any one?  The file has  many ancestry directories, and how can I verify that? How is momentum conserved in this example?