(Ubuntu 16.04) Where can I find gthread-2.0?
How do I find the package that provides a file?
What is the proof that the universal constants ($G$, $\hbar$, $\ldots$) are really constant in time and space? When should I publish in interdisciplinary versus subject-specific scientific journals? Most science research is published in subject-specific journals, of which there are many. However, there are a relatively small number of interdisciplinary journals, some of which are the most highly cited of all journals (Nature, Science); others have impact factors comparable to subject-specific journals (e.g., PLOS ONE, J. R. Soc. Interface, etc.).  If we discount arguments around open science and similar business model arguments (which could favor journals like PLOS ONE), and assume that the purpose of publishing is simply to get your research read (and cited) by the largest "relevant audience", when should one publish in an interdisciplinary journal versus a subject-specific journal (assuming they have comparable impact factors)? (Are there any papers out there that compare the fate of publications [or their authors!] in the two different types of journal?)  Thanks in advance. I understand that the eigenvectors of a linear transformation are the vectors that, when transformed, are simply scaled by a factor of the corresponding eigenvalue. Therefore $$ A\vec{x}=\lambda\vec{x}. $$ We can replace the scaling of the vector $\vec{x}$ by $\lambda$ with its equivalent linear transformation, $\lambda I$. Then we can rearrange this equation as follows: $$ A\vec{x}-(\lambda I)\vec{x}=\begin{bmatrix}0\\0\end{bmatrix}\\  (A-\lambda I)\vec{x}=\begin{bmatrix}0\\0\end{bmatrix}\\  $$ For this to be true either $\vec{x}$ must be a zero vector or the transformation $A-\lambda I$ must have $\vec{x}$ in its null-space. The course I'm following says that we can solve for $\lambda$ by finding when the determinant of $A-\lambda I$ is zero, but why does that guarantee that $\vec{x}$ will become the zero vector when transformed by $A-\lambda I$? I understand that for $\vec{x}$ to be an eigenvector this transformation must have a determinant of zero, but I don't see how the inverse can be true; having a determinant of zero doesn't gaurantee that $\vec{x}$ will be transformed into the zero vector. For example, let $$ (A-\lambda I) = \begin{bmatrix}1&amp;2\\0&amp;0\end{bmatrix}, \vec{x}=\begin{bmatrix}1\\1\end{bmatrix} $$ Then, although $\det\begin{bmatrix}1&amp;2\\0&amp;0\end{bmatrix} = 0$, it does not gaurantee $(A-\lambda I)\vec{x}$ to be the zero vector. $$ \begin{bmatrix}1&amp;2\\0&amp;0\end{bmatrix}\begin{bmatrix}1\\1\end{bmatrix}=\begin{bmatrix}3\\0\end{bmatrix}  $$ We can see that the transformation gives us $\begin{bmatrix}3\\0\end{bmatrix}$ and not the zero vector. Why does finding when the determinant of this transformation is equal to zero help us find the eigenvectors? Am I missing something? I am a newbie in linux and I don't know how to open the Ubuntu Software Center via Terminal!! Please help What exactly is heat? Is it energy?  Is it energy per unit volume?  Is it energy per unit time i.e power?  What is it? Labelled spanning trees of $K_n-e$ Let $e$ be an edge of $K_n$- the complete graph on $n$ vertices. Prove that the number of labelled spanning trees of $K_n-e$ is $(n-2)n^{n-3}$.  I think the answer lies in using some modified form of Prüfer's sequence but I can't quite nail it. When activating the evolution for a caught Pokemon, it seems to amplify the Combat Power (CP). Thus it seems most beneficial to evolve your Pokemon with the highest CP, if you have multiple of the same kind.   But what I am not sure about is whether it makes an efficiency difference if you spend candies and dust to boost CP before evolving, to gain more from the amplification? Or is it more efficient to just evolve without spending, and then using the leftover candies afterwards, since they now give a bigger CP boost per candy?   I only tested with a Rattata so far, which gained +8 CP per candy before evolving, and +15 CP afterwards. I collected no numbers on the amplification efficiency though, and now ran out of materials for further testing.  Or maybe it is a balanced calculation and makes no difference at all? I would love to have some insight on that.    Some data I collected thus far: (GPC = CP gain per candy)  79 CP Weedle (GPC 6) evolved to: 84 CP Kakuna (GPC 6), evolved at 90 CP to: 297 CP Beedrill    Note: The max-CP "half circle" in the profile stayed filled roughly at the same relative position throughout the evolutions. Problems installing xpatch I need to install the xpatch package to make changes to my biblatex setup. The readme file in the install package simply says to run “latex xpatch.ins.” I've moved the xpatch folder (including xpatch.ins and xpatch.dtx files) to the /usr/local/texlive/2011/../texmf-local/ folder. When I run the command above, I get the output Generating file(s) ./xpatch.sty  ! Cannot find file xpatch.dtx. \readsource ...ot find file \uptospace #1 \qStop }                                                   \else \processedLines \z@ ... l.34 ...xpatch.sty} {\from{xpatch.dtx} {package}}}   I've checked, and the .dtx file is in the folder. Any ideas what the problem is? Usage of -n and -z in test built in - Bash How to properly denoise renderings? Since the Denoise feature was added to Blender I only use the default setting with it and it really does the work. But sometimes the denoise is noticable on some of my renders. How can I overcome the blurred effect? Denoising for me is a big help because my system is quite aged. Prime factorizations of consecutive numbers, can they both contains powers of greater than or equal to $1000$? The equation $X^{n} + Y^{n} = Z^{n}$ , where $ n \geq 3$ is a natural number, has no solutions at all where $X,Y,Z$ are intergers. I am taking a course in Differential Topology right now, but I know of another Subject called "Riemannian Geometry" which studies Riemannian Manifolds. The definition of a real smooth manifold and a Riemannian Manifold are very similar except for the detail that makes them Riemannian (having a inner product on the tangent space of every element which varies smoothly with respect to this element of the R. Manifold).  So my question is: is there any example of a Smooth Manifold that is NOT a Riemannian Manifold?  Thanks. What is the CVE-2014-6271 bash vulnerability (Shellshock) and how do I fix it? How do I efficiently get "the most recent corresponding row"? 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. How to draw tangent vectors and component vectors on a curve I am searching for a way to have a figure drawn using LaTeX. I am aware of some packages TikZ and PSTricks that could accomplish this, and have been tinkering around with them recently but do not have enough skill set at the moment to accomplish this drawing. Is there a way someone can accomplish the drawing, preferably with TikZ but could be any package your most comfortable with in a reduced amount of coding (non-advanced) to where I could understand what is happening from the code to the picture. If this is not possible, then I will have to study the package more and work with it until I understand the method (code) to create the graphic. The drawing is below.  Note: This is a rough sketch. The optimal output would have smooth quadratic curves and all quantities are vectors. What do the brackets around processes mean? $ ps -Awwo pid,comm,args   PID COMMAND         COMMAND     1 init            /sbin/init     2 kthreadd        [kthreadd]     3 ksoftirqd/0     [ksoftirqd/0]     5 kworker/u:0     [kworker/u:0]     6 migration/0     [migration/0]     7 cpuset          [cpuset]     8 khelper         [khelper]     9 netns           [netns]    10 sync_supers     [sync_supers]    11 bdi-default     [bdi-default]    12 kintegrityd     [kintegrityd]    13 kblockd         [kblockd]    14 kacpid          [kacpid]    15 kacpi_notify    [kacpi_notify]    16 kacpi_hotplug   [kacpi_hotplug]    17 ata_sff         [ata_sff]    18 khubd           [khubd]   What do the brackets mean? Does args always return the full path to the process command (e.g. /bin/cat)? Deploy Community Builder audience page assignments with ant migration tool? "I don't know nothing" vs "I don't know anything" Possible Duplicate:             I'm not a native English speaker, and this question may be very basic, but I want to learn English better, so don't hurt me with downvotes.  What is the difference between "I don't know nothing" and "I don't know anything"?  Do they have the same meaning or opposite ones? Google Chrome (Windows) not displaying text/encoding correctly on certain websites I experience a problem similar to    Here's a screenshot on the website     I've tried:   Removing fonts I have installed Setting the encoding to Western, UTF-8, Greek, Automatic Changing the fonts used in Google Chrome Removing Google Chrome, including all application data/user profiles Running CCleaner Reinstalling Google Chrome, twice Installing Chromium (fonts display fine in Chromium) Turning off Windows ClearType Changing Windows/Chrome languages from English (Australia) to US, UK Restarting Windows several times after making changes   All of which did not work. I do not connect over VPN/proxy.   Can anyone give me any tips?  Windows 7 x64 Ultimate