I'm having a strange issue in Ubuntu 16.04.2. Some programs will only start after a delay of roughly 20-30 seconds, or will have this delay when opened a certain way, but not another.  Here are some example programs:  Slow startup:   Chromium/Chrome Terminal (when started with Ctrl+Alt+T) Opera   Normal startup:   Firefox Terminal (When started from Launcher or Dash) Spotify Steam   I can't see any connections, as the slow startup seems to affect both pre-installed/native programs and 3rd party programs.  I've encountered this problem before, and tried re-installing Ubuntu. It worked fine for about a month before it showed back up. Also didn't have the problem when running from USB, so probably isn't hardware. Each time the problem has arisen, is after I've been using mostly Windows for some time, but that's installed on a separate SSD, and it can't read the filesystem on the Linux disk, so I don't think it's Windows' fault.  Most website logins seem to be forgotten once the problem manifests itself, and one website even thought I was on a new machine.  I already know that re-installing Ubuntu works (at least for a while), but I'm wondering if anyone has any idea what could be causing this, or what I can do to narrow it down.  There's free memory and swap, and low CPU usage.  Thanks for having a look!  Update: Tried installing a couple other desktop environments/window managers(?). Switching to XFCE removes the delay when trying to start a terminal with Ctrl+Alt+T, but it's still there for the other programs. Ctrl+Alt+T (and other programs) still slow in GNOME.
When I start up Ubuntu 16.04 some applications take too long to run the first time I open them, including Chrome and any PDF viewer. Others, like nautilus, start up immediately.  The first time I try to use a PDF viewer like okular, it takes too long to open. After it opens a PDF file for the first time, other files open quickly. Even if I close all and open some after a long time, it happens quickly.  How can I speed up these programs opening on the first run?
Shiny locked Legendaries in ORAS Serebii says that (probably) the only  in ORAS are Kyogre, Groudon, Rayquaza and Deoxys. This means that Reshiram and Zekrom, that were shiny locked in BW/B2W2, now can be found shiny.    Can anyone prove this? I'd like to know if it's true before waste hours in softresetting. Force new users to go through animated tutorial before they post for the first time Do not allow people to post the minute they created an account.  Let them ask the question but not allow them to post.  Let them stew for 30 minutes and force them through a nice animated tutorial on what they should do before they post and enforcing the fact that bad questions will not get an answer.  If they had a Need to know! basic rules introduction forced on them asking them at the end to check a box I understand! some might ask better questions and help the community instead of flooding the site with bad questions.  The presentation should be on a timer without the ability to skip and highlight the similar questions asked before that might give them the answer.  Also for the first next 9 posts they should have to check a box next to the first 5 of each similar questions before posting.  I do not mean to be harsh, but the truth is I see more negative votes on questions then positive. It's like 90% of the time people give -1 to first questions. I have a query pattern that must be very common, but I don't know how to write an efficient query for it.  I want to look up the rows of a table that correspond to "the most recent date not after" the rows of another table.  I have a table, inventory say, which represents the inventory I hold on a certain day.  date       | good | quantity ------------------------------ 2013-08-09 | egg  | 5 2013-08-09 | pear | 7 2013-08-02 | egg  | 1 2013-08-02 | pear | 2   and a table, "price" say, which holds the price of a good on a given day  date       | good | price -------------------------- 2013-08-07 | egg  | 120 2013-08-06 | pear | 200 2013-08-01 | egg  | 110 2013-07-30 | pear | 220   How can I efficiently get the "most recent" price for each row of the inventory table, i.e.  date       | pricing date | good | quantity | price ---------------------------------------------------- 2013-08-09 | 2013-08-07   | egg  | 5        | 120 2013-08-09 | 2013-08-06   | pear | 7        | 200 2013-08-02 | 2013-08-01   | egg  | 1        | 110 2013-08-02 | 2013-07-30   | pear | 2        | 220   I know one way of doing this:  select inventory.date, max(price.date) as pricing_date, good from inventory, price where inventory.date &gt;= price.date and inventory.good = price.good group by inventory.date, good   and then join this query again to inventory. For large tables even doing the first query (without joining again to inventory) is very slow.  However, the same problem is quickly solved if I simply use my programming language to issue one max(price.date) ... where price.date &lt;= date_of_interest ... order by price.date desc limit 1 query for each date_of_interest from the inventory table, so I know there is no computational impediment.  I would, however, prefer to solve the whole problem with a single SQL query, because it would allow me to do further SQL processing on the result of the query.  Is there a standard way to do this efficiently? It feels like it must come up often and that there should be a way to write a fast query for it.  I'm using Postgres, but an SQL-generic answer would be appreciated. In Drush 8, my site aliases are loaded correctly from ~/.drush/mysite.aliases.drushrc.php.  E.g.  $aliases['dev'] = array(   'root' =&gt; '/var/www/html/mysite.dev/docroot',   'uri' =&gt; 'mysite.prod.acquia-sites.com',   'remote-host' =&gt; 'mysite.ssh.acquia-sites.com',   'remote-user' =&gt; 'mysite.dev',   'path-aliases' =&gt; array(     '%drush-script' =&gt; 'drush' . $drush_major_version,   ), );   However these aliases aren't loaded in Drush 9.  $ drush site-alias {  }   How I should define site aliases in Drush 9? Is there any migration process? Proof of one inequality $a+b+c\leq\frac{a^3}{bc}+\frac{b^3}{ca}+\frac{c^3}{ab}$ How to prove this for positive real numbers? $$a+b+c\leq\frac{a^3}{bc}+\frac{b^3}{ca}+\frac{c^3}{ab}$$  I tried AM-GM, CS inequality but all failed. I've always wondered what the deal was with Darth Vader's "crotch door". Does he use a catheter (due to all his injuries) or does he simply flip the door up and whip it out? I've never really seen the the back of his suit under his cape to see if there a corresponding "back door".   It doesn't look like he carries a catheter bag nor a colostomy bag in his suit or anything.     Is this addressed anywhere either in canon or legends sources? Show an Ideal is the principal ideal for some polynomial. Let $F$ be a ﬁeld and $R = F[X]$. Suppose $I$ is an ideal of $R$. Show that $I = (p(X))$ for some $p(X)$ in $F[X]$. (Hint: consider a polynomial $p(X)$ of least degree in $I$.)  I'm trying to do this question but can't seem to start. if anyone could give me a hint that would be appreciated.  My instinct was to take a monic polynomial (which exists since we are in a field) of degree $1$ and divide given the first two parts of the question were about polynomial division.  Thanks. Find the integer solutions: $$a·b^5+3=x^3,a^5·b+3=y^3$$ This is the first problem of today's USAJMO (has finished),I only find a trival result that $x\equiv y \pmod6$ and $abxy≠0 \pmod 3$.  Thanks in advance! Links in site profiles stripped from network profile I have a link in my profile, advertising a Stack Exchange question of mine (which I believe is acceptable use of the profile page). The link works fine on my individual profile pages. For example,  and . However, on  the links do not show.  The link is present on the GIF and on the text (two separate links, both to the same place). Both work fine on the individual profile pages but both are absent from the network profile page. The GIF and text are present, just without being linked.  Is there a reason for disallowing links from the network profile page, or is this a bug? From Berkeley Problems in Mathematics, Spring 1999, .  Let $f(x)\in \mathbb{Q}[x]$ be an irreducible polynomial of degree $n\ge 3$. Let $L$ be the splitting field of $f$, and let $\alpha\in L$ be a zero of $f$. Give that $[L:\mathbb{Q}]=n!$, prove that $\mathbb{Q}(\alpha^{4})=\mathbb{Q}(\alpha)$.   (BELOW IS NONSENSE, SHOULD BE IGNORED)  Following Gerry Myerson's advice, since $L$ is the splitting field of $f$, $L$ must be Galois over $\mathbb{Q}$. Thus the Galois group for $[L:\mathbb{Q}]=S_{n}$. Gerry now asserts that either $\mathbb{Q}(\alpha^{4})$ is of degree 2 over rationals or it must be $\mathbb{Q}$. But assuming this one can rule out the case $\mathbb{Q}$, since this would imply $\alpha$ is the root of a 4th or 2nd degree polynomial over $\mathbb{Q}$. But we know $n\ge 3$. So $\alpha$ must be the root of a 4th degree polynomial. We know $S_{n}$ has normal subgroups $A_{n}$ when $n\not=4$ and $V,A_{4}$ when $n=4$. I do not know how to proceed any further.   Now assuming $\mathbb{Q}(\alpha^{4})$ is a degree 2 abelian extension over $\mathbb{Q}$. We should have a chain of normal extensions $\mathbb{Q}(\alpha)\supset \mathbb{Q}(\alpha^{2})\supset \mathbb{Q}$. This would imply $S_{n}$ has a normal subgroup which has a normal subgroup. But we know $A_{n}$ for $n\ge 5$ are simple. So the only possibility is $\mathbb{Q}(\alpha)$ has a Galois group isomorphic to $V$. In this case $n=4$ as well. I can only proceed to here. I am working on the following problem asked in an examination: "What is the maximum number of cylindrical pencils of 0.5 cm diameter that can be stood in a square shaped stand of 5cm × 5cm inner cross section? 1. 99    2. 121   3. 100    4. 105." A simple calculation yielded me the answer 100.  But the answer in the key is 105. I don't how such an answer is possible. Any hint please.....Thanks in advance! Rerender funnel highcharts with new data I'm working in C, and I have to concatenate a few things.  Right now I have this:  message = strcat("TEXT ", var);  message2 = strcat(strcat("TEXT ", foo), strcat(" TEXT ", bar));   Now if you have experience in C I'm sure you realize that this gives you a segmentation fault when you try to run it. So how do I work around that? Proof that a Combination is an integer From its definition a combination $\binom{n}{k}$, is the number of distinct subsets of size $k$ from a set of $n$ elements.  This is clearly an integer, however I was curious as to why the expression  $$\frac{n!}{k!(n-k)!}$$ always evaluates to an integer.  So far I figured:  $n!$, is clearly divisible by $k!$, and $(n-k)!$, individually, but I could not seem to make the jump to proof that that $n!$ is divisible by their product. I am using MiKTeX 2.9 on Windows 7.   I'm getting the error: "can't write on pdf file."  The pdf doesn't reflect what I wrote.  What did I do wrong?  My input:  \documentclass[12pt]{article} \usepackage{epsf} \usepackage{amssymb} \usepackage{graphicx} \usepackage{setspace} \usepackage{amsmath} \usepackage{rotate} \usepackage{endnotes} %\usepackage{harvard} \usepackage{vmargin} \usepackage[nolists,noheads,tablesfirst,nomarkers]{endfloat} \usepackage{natbib} \bibliographystyle{apsr}  \oddsidemargin=1.0in\evensidemargin=0.in \textheight=8.5in\textwidth=6.6 in \baselineskip=18pt \parskip=6pt  \begin{document}  % added, was missing  TEXT  \newpage \baselineskip=12pt \doublespacing  \bibliographystyle{apsa} \bibliography{Dissertation_Proposal}   \end{document} When two objects -one of them transparent- intersects it creates some artifacts visible even in the alpha channel. Even with 1024 transparent bounces the artifacts remain.    In the example file there are two cubes in the same position, one transparent and one emission.    What is causing this? Any way to get rid of this artifacts? Convergence of the series $\sum a_n$ implies the convergence of $\sum \frac{\sqrt a_n}{n}$, if $a_n>0$ I need help to solve following problem from Rudin's Mathematical analysis book:    Convergence of the series $\sum a_n$  implies the convergence of $\sum \dfrac{\sqrt {a_n}}{n}$, if $a_n&gt;0$  I tried to construct a suitable convergence sequence $b_n$ such that $\sum b_n$ converges and $a_n \leq b_n$ but, I am not able to find such sequence $b_n$ .  Thanks for the help and sugestions. How does Java's serialization work and when it should be used instead of some other persistence technique? I've been lately trying to learn more and generally test Java's serialization for both work and personal projects and I must say that the more I know about it, the less I like it. This may be caused by misinformation though so that's why I'm asking these two things from you all:  1: On byte level, how does serialization know how to match serialized values with some class?  One of my problems right here is that I made a small test with ArrayList containing values "one", "two", "three". After serialization the byte array took 78 bytes which seems awfully lot for such low amount of information(19+3+3+4 bytes). Granted there's bound to be some overhead but this leads to my second question:  2: Can serialization be considered a good method for persisting objects at all? Now obviously if I'd use some homemade XML format the persistence data would be something like this  &lt;object&gt;     &lt;class="java.util.ArrayList"&gt;     &lt;!-- Object array inside Arraylist is called elementData --&gt;     &lt;field name="elementData"&gt;         &lt;value&gt;One&lt;/value&gt;         &lt;value&gt;Two&lt;/value&gt;         &lt;value&gt;Three&lt;/value&gt;     &lt;/field&gt; &lt;/object&gt;   which, like XML in general, is a bit bloated and takes 138 bytes(without whitespaces, that is). The same in JSON could be   {     "java.util.ArrayList": {         "elementData": [             "one",             "two",             "three"         ]     } }   which is 75 bytes so already slightly  smaller than Java's serialization. With these text-based formats it's of course obvious that there has to be a way to represent your basic data as text, numbers or any combination of both.  So to recap, how does serialization work on byte/bit level, when it should be used and when it shouldn't be used and what are real benefits of serialization besides that it comes standard in Java? Why is the "Arnold Schwarzenegger" terminator referred to by two different product numbers (T-101, T-800)? Help center still has the guidance about old Favorite tags