I am concerned about something. I would like to install a Password manager called , it's a free and open source community maintained version of KeepassX. I am debating whether to use the .AppImage or the .snap package for the installation process found on their downloads page.       I've successfully downloaded and verified the .AppImage package. I thought I remember seeing an article that said that .snap packages are automatically verified when downloaded and installed on your system. Is this true? I understand that .AppImage packages do not require root access to run. Snap packages however do. I also heard that .snap packages are dying and are not very popular since Unity 8 died. Which one is more secure? Does Canonical maintain and review .snap packages? Which one is better in your opinion? I have barely used both of these. I've only downloaded and used a .AppImage and .snap package once so I'm not too familiar or an expert when it comes to these types of packages. I would like to know the difference and pros and cons of these two types of packages security wise. Thanks!
I have been getting this question lately from students and although I have a lot of information to offer, I have not found a source that I can point people to where they can read an update answer (I have found a lot of misinformation and obsolete information). So, some of the questions I have for package formats like snap, appimage, flatpak and others in this evolution of universal packaging systems are:   Who created the package format? What features does it offer? What features are unique to it? (That the others do not yet have) Who supports it? What Distributions use it? What focus does the package have? (For Desktop, Clouds, Mobile, etc..) Which are more actively developed?
Comma before "and" in compound sentences? I read this sentence on an educational website:     Now times have changed and you are ready for situations involving forces in two dimensions.   Shouldn't there be a comma before and, since the subject of the sentence has changed (things vs. you)?      Now times have changed, and you are ready for situations involving forces in two dimensions.   What is the exact comma rule for joining two clauses with and? I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck converter to adjust it (and CC mode, displays and blinky stuff).   I thought it would be a good idea to use a linear regulator on the output stage to smooth things out, but I can't seem to think of a control scheme that allows me to change the voltage using only one potentiometer. The buck stage is this topology but with a external PNP transistor.(It has already been prototyped, it works alright, I know the mc34063A is old)   The only idea I got that ""works"" is using the buck converter output as a reference for a linear regulator (IC or discrete parts), but using a SMPS output as reference for anything is a bad idea, due to the amount of noise and fluctuations.   This is the sort of output stage I can and have built (or bought) over time. Just a big discrete regulator.  In short: How to control a MC34063A step down (buck) converter so it follows the output stage +1-3 V of headroom. I can successfully tether my Mac (10.7.3) to my iPhone4 (5.0.1) via wifi, no problem, been doing it for months.  However, when I try to tether via bluetooth instead, I can't seem to see the internet from my mac.  Network Settings reports a green light for Bluetooth PAN, but my browser can't connect to anything at all.  My Mac reports very similar IP addresses for both, starting with 172.20.10 and differing only in the last octet.  Any idea why I can't successfully tether via bluetooth? SQL Azure and Full-Text Catalogs, Indexes and Searching How can I find the version of Ubuntu that is installed? I'm trying to install Windows 8 on my pc via Microsoft Virtual PC.  However I get this annoying, non-descriptive error:    I'm looking to find out if Microsoft Virtual PC supports Windows 8, and if so how do I solve this issue?  NOTE: I'm NOT trying to ask for alternatives to Virtual PC, but rather trying to figure out if it's possible, and if so how, to use Virtual PC. Down Arrow Key is not working How do I enable hardware virtualization technology (VT-x) for use in Virtualbox? Absolute path & Relative Path What's the difference between absolute path &amp; relative path when using any web server or Tomcat? What is the first movie to show this hard work message at the very end? What is the first movie to show this hard work message at the very end? Measure the size of a PostgreSQL table row I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some other factor. I need all of the fields (or nearly all of them), so selecting just a subset isn't a quick fix. Selecting the fields that I want is still slow. Here's my table schema minus the names: integer                  | not null default nextval('core_page_id_seq'::regclass) character varying(255)   | not null character varying(64)    | not null text                     | default '{}'::text character varying(255)   |  integer                  | not null default 0 text                     | default '{}'::text text                     |  timestamp with time zone |  integer                  |  timestamp with time zone |  integer                  |   The size of the text field may be any size. But still, no more than a few kilobytes in the worst case. Questions  Is there anything about this that screams 'crazy inefficient'? Is there a way to measure page size at the Postgres command-line to help me debug this? Auto delete spam email from a domain in Gmail Cheaper zoom lenses usually are faster at the wide end and slower at the long end (for example, the $150 Canon EF-S 18-55mm f/3.5-5.6). More expensive constant-aperture zoom lenses have the same aperture regardless (for example, $800 Canon EF 17-40mm f/4.0 L).  My question is: are these good lenses  at the wider settings, or do they have a different optic system that allows them to maintain the same aperture throughout the zoom range? Free ornaments font I'm looking for a free ornaments font. I know about  and pifont. Where can I find more glyphs? What is the proper way to handle data between scenes? I am developing my first 2D game in Unity and I have come across what seems an important question.  How do I handle data between scenes?  There seems to be different answers to this:   Someone mention using , while other people told me this should be used to store other things like screen brightness and so on. Someone told me that the best way was to make sure to write everything into a savegame everytime that I changed scenes, and to make sure that when the new scene loads, get the info from the savegame again. This seemed to me wasteful in performance. Was I wrong? The other solution, which is the one I have implemented so far is to have a global game object that isn't destroyed between scenes, handling all the data between scenes. So when the game starts, I load a Start Scene where this object is loaded. After this ends, it loads the first real game scene, usually a main menu.   This is my implementation:  using UnityEngine; using UnityEngine.UI; using System.Collections;  public class GameController : MonoBehaviour {      // Make global     public static GameController Instance {         get;         set;     }      void Awake () {         DontDestroyOnLoad (transform.gameObject);         Instance = this;     }      void Start() {         //Load first game scene (probably main menu)         Application.LoadLevel(2);     }      // Data persisted between scenes     public int exp = 0;     public int armor = 0;     public int weapon = 0;     //... }   This object can be handled on my other classes like this:  private GameController gameController = GameController.Instance;   While this has worked so far, it presents me with one big problem: If I want to load directly a scene, let's say for instance the final level of the game, I can't load it directly, since that scene does not contain this global game object.  Am I handling this problem the wrong way? Are there better practices for this kind of challenge? I would love to hear your opinions, thoughts and suggestions on this issue.  Thanks Fantasy Short Story that appeared in an anthology about 1968-1971 I read this short story around 1971.  The basic plot is for a steward to lead the king's son to another city state.  Along the way they have a number of interactions with people/subjects that demonstrate the immaturity of the son.  Last one involves the son beating up the suitor of a innkeeper's daughter.  When confronted by the steward, the son displays his contempt and chauvinistic regard of his future subjects and the steward kills him.  Turns out the trip was a test of his suitability to assume the crown and the steward explains to the king that he was not worthy.  Been looking in all the anthologies can seem unable to find it.  Thanks for your help Projection of a point onto a simple convex polytope I have a convex polytope described by the intersection of a hypercube and two parallel lower and upper hyperplanes cutting through the hypercube. I want to find the projection of a point onto the polytope. I read the question  and see that the general problem of finding a projection onto a convex polytope can be solved with quadratic programming. However, taken alone, projection onto a hypercube or a hyperplane is trivial. For the hypercube, each dimension is defined by a lower+upper bounds and we just pull each dimension within those bounds, which take $O(n)$ time in $n$ dimensions. For the hyperplane just find the projection onto it. So I'm wondering whether there is simpler method for finding such a projection, maybe somehow combining the two independent projections. I have a PDF with 100 pages. How can I make a new PDF that displays 4 pages on one?  I know that I can do it with Chrome by printing the PDF to new PDF and change this in the options. But I want to make it for a lot of files and put it as a script. Show that   $$\displaystyle1 - \frac{x^2}2\leq\cos x\quad\forall x \in \mathbb{R}$$   Let $f(x) = \cos x - 1 + \frac{x^2}2$; then we need to show that $f(x) \geq 0\quad\forall x \in \mathbb{R}$.  Since $$\lim_{x \to \pm\infty} f(x) = +\infty$$ and $$\operatorname{im}f'' = [0, 2]$$ (as $f''(x) = 1 -\cos x$), it remains to show that $x = 0$ is a minimum for $f(x)$, but I cannot do that because I would need to solve $f'(x) = x -\sin x = 0$, which I cannot. I think it would suffice to show that plugging in $x = 0$ we have that $f'(x) = 0$, and combining it with the fact that the function $f$ is convex, we would be done.    Is it enough? What's a better proof?  EDIT: It just occurred to me that there is a way to solve $f'(x) = 0$. Just observe that $f'(x)$ is an odd function and that $f''(x) \geq 0$ implies that $f'(x)$ is monotonically increasing. Since an odd function, if defined at $x = 0$, must be $0$ there, $x = 0$ is a solution to the equation and it's the only one. Question on how to normalize regression coefficient Not sure if normalize is the correct word to use here, but I will try my best to illustrate what I am trying to ask. The estimator used here is least squares.  Suppose you have $y=\beta_0+\beta_1x_1$, you can center it around the mean by $y=\beta_0'+\beta_1x_1'$ where $\beta_0'=\beta_0+\beta_1\bar x_1$ and $x_1'=x-\bar x$, so that $\beta_0'$ no longer has any influence on estimating $\beta_1$.  By this I mean $\hat\beta_1$ in $y=\beta_1x_1'$ is equivalent to $\hat\beta_1$ in $y=\beta_0+\beta_1x_1$. We have reduced equation for easier least square calculation.  How do you apply this method in general? Now I have the model $y=\beta_1e^{x_1t}+\beta_2e^{x_2t}$, I am trying to reduce it to $y=\beta_1x'$.