70s/80s SF short story about a bullied scientist who develops a new type of simple but deadly nuclear weapon

Back in the late 70s or early 80s, I read a short story in an anthology of science fiction (possibly The Year's Best series) about a scientist who has developed a new type of nuclear weapon.   The technique is so simple but devastating that he is sure if he releases his work, all of humanity will be destroyed.   He reflects back on his life, revealing he was a genius at an early age and brutally bullied and beaten by classmates. He was nicknamed "Sally" which crushes his confidence around women later in life (he mentions he couldn't even date a woman named Sally as an adult).  He ends the story by saying "I would kill you all slowly if I could" and reveals his work to the world.  The story was in English. I read it at the Mt. Washington branch of the Cincinnati Library.


I need to configure proxy. There wasn't apt.conf file in etc/apt/ so I've created it using nano.   But I don't understand what I need to write there. I've written  http_proxy = http://lgn:pwd@192.168.1.254:8080/ there and then restarted networking. But when I try to apt-get update - it doesn't work.   Actually I don't understand what port and ip I should write in apt.conf file(there was example with 192.168.1.254 ip and 8080 port so I decided to use them).


Multiuser - can process of background user kept running?

On my Mac I use three user accounts. From what I understand when I'm logged in as one the processes of the other accounts are suspended. I switch between them with fast user switching.  My question is - can one assure that some processes keep running? Searching I found a few hints how to do on command line - but I'm considering to let a graphic application - like Steam - update itself for one user, and work as another user at the same time.


How to prevent polyglossia german and pgfmath from clashing?

I've recently tried the tikz wheel from this other thread:  - it all works fine until I switched polyglossia to german. This fails with  Extra }, or forgotten \endgroup.  \documentclass{article} \usepackage{polyglossia} \setdefaultlanguage{german} \usepackage{graphicx} \usepackage{tikz} \begin{document}     \begin{tikzpicture}         \pgfmathparse{(5? "west" : "east" )}  % Apprently these quotes are  the culprit.     \end{tikzpicture} \end{document}  This works \documentclass{article} \usepackage{polyglossia} \setdefaultlanguage{german} \usepackage{graphicx} \usepackage{tikz} \begin{document}     \begin{tikzpicture}         \pgfmathparse{(5? 5 : 4 )} % This does not make sense but works     \end{tikzpicture} \end{document}  As we can easily see the quotes around east seem to be problem. How can I bypass this?


Why does dust stick so well to fan blades?

After reading and understanding the reasons , I am interested to find out why the dust particles stick so well. Spraying powerful jets of water does not effectively remove the dirt. Some scrubbing is still required, whether it is metallic blades or plastic ones.  Why is that so?


How to get value from {{ item.content }}

I have a node named "reviews" and a custom field named "field_rating". I created a field template named field--node--field_rating--reviews.html.twig.  I want inside the node to change the color with an if statement.  I try to do something like that:  {% for item in items %}   {% if item.content > 5 %}
{{ item.content }}
   {% endif %} {% endfor %}   but it doesn't work.  Any suggestions?  Drupal Version 8.6.1


I have written this paper and I would like to ask, via email, from some professors in other universities to give me feedback. How is the best way to write such a request? First, what should I write in the email subject box? Then, how do I write the body of email?


Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point?   I'm guessing it has to do with using WCS, but no examples seem to exist for doing this!  This will be similar to querying PostGIS with ST_Value(raster, ST_SetSRID(ST_Point(lon,lat),4326)). I dont really want to import the same raster into PostGIS just to find the raster value at a point. Or is this the recommended solution?


I like to generate correlated variables with a existing variable in R

In R, I like to create a set of variables that are correlated with a given variable.I scanned related questions but failed to find the same issue i have.  Here is instance.  x<-rnorm(100, mean=3,sd=1.2)   Assuming $x$ is an exiting variable, I like to generate $z, y, t$ correlated variables with $4$ by $4$ correlation matrix.   So, variables $y, t, z$ would correlate $x$ according to predefined correlation matrix I will use as an input. It would be grateful if you leave a comment on me with a specific code.


Finding an orthonormal basis for a matrix

If we have a subspace W of $\mathbb{R}^2$ spanned by $(3,4)$. Using the standard inner product, let E be the orthogonal projection of $\mathbb{R}^2$ onto W. Find an orthonormal basis in which E is represnted by the matrix: $\begin{bmatrix}     1      & 0  \\     0      & 0  \end{bmatrix}$  Now I figured out that $E(x_1,x_2) = \frac{1}{25}(9x_1+12x_2,12x_2+16x_2)$ and that the matrix for $E$ in the standard ordered basis is  $\frac{1}{25}\begin{bmatrix}     9      & 12  \\    12      & 16  \end{bmatrix}$. From here how would I figure out what the orthonormal basis is? I know that since the eigenvalues of $E$ are $\lambda =0,1$ then the basis for the other representation should be the unit eigenvectors. Would this be correct? It doesn't make sense to me because the orthonormal basis where the matrix representation of $E$ is the latter is just $\{(\frac{3}{5},\frac{4}{5})\}$ which does not span all of $\mathbb{R}^2$, but taking the eigenvectors would span all of $\mathbb{R}^2$.


When does $\sqrt{a b} = \sqrt{a} \sqrt{b}$?

So, my friend show me prove that $1=-1$ by using this way:  $$1=\sqrt{1}=\sqrt{(-1)\times(-1)}=\sqrt{-1}\times\sqrt{-1}=i\times i=i^2=-1$$  At first sight, I stated "No, $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ is valid only for $a,b\in\mathbb{R}$ and $a,b\geq0$"  But, I remember that $\sqrt{-4}=\sqrt{4}\times\sqrt{-1}=2i$ which is true (I guess).  Was my statement true? But, $\sqrt{ab}=\sqrt{a}\times\sqrt{b}$ is also valid if one of a or b is negative real number. Why is it not valid for a dan b both negative? If my statement was wrong, what is wrong with that prove?


i came across  and i saw the given solution but i can not understand how it proves the given problem. Ok i get that $lcm(5,7)= 35$ and it is the same as the $(mod 35)$. Please can someone help me?


How do I replace a string on a large file?

I'm having big WordPress SQL dump file on my Ubuntu server which is around 7GB. Since I'm changing domain I need to replace the domain name in the file. I want to know how to do it via command line.  dev.example.com   Needs to replace with  example.com


Likelihood is not "proportional to" a single probability density?

In various places it says that the likelihood (e.g. in the Bayes formula) is "proportional to a probablility".  For example  "likelihood is proportional to a probability"  A similar statement is in the book Think Bayes, "likelihood doesn't need to compute a probability, it only has to compute something proportional to probability"  Lastly, in a crossvalidated discussion   there is a more specific statement "the likelihood function is proportional to the probability of the observed data."  I am not sure if that is correct or not.  Notation, $P(A|B) = P(B|A) P(A) / P(B)$.  The likelihood is $P(B|A)$.  The question: If I am understanding however, the likelihood is proportional to a different probability for each value of $A$. That is, there is no single constant $c$ such that the likelihood is equal to some version of the probability $P(B)$, i.e. this statement is false $$     P(B) = c \cdot P(B|A) $$ Rather, it would have to be $$     P(B) = c(A) \cdot P(B|A) $$ meaning that the constant of proportionality $c$ varies with each choice of $A$.  Is this true?  If so, it seems to me that saying likelihood is proportional to a probability is vacuous. You can always make something "proportional to" something else if the proportionality is a function rather than a constant.  This question is somewhat related to these previous questions about likelihood, which I have read, however I believe this is a different question (albeit maybe one that could be "derived from" the answers to other questions, buy someone smarter than me!)      EDIT: Maybe another way of asking the question is this: if the likelihood is proportional to a probability, which probability is it proportional to?  Is it the probability $P(B|A)$ regarded as a function of B with A held fixed, or is it the marginal probability P(B), or is it some other (generic) probability?  EDIT: here is an attempt at an example:  A Normal distribution is parameterized by mean and variance. Let's pick something simpler,a PMF that is parameterized only by a single parameter $M$.  It assigns probabilities to integer values,  and the parameter translates the PMF on the integer axis. Here is the PMF for the parameter value M=5: $$ \begin{align*} &  P(X=5|M=5) = .5  \\ &  P(X=6|M=5) = .3  \\ &  P(X=7|M=5) = .2  \\ \end{align*} $$ And the PMF for parameter value M=6: $$ \begin{align*} &  P(X=5|M=6) = 0  \\ &  P(X=6|M=6) = .5 \\ &  P(X=7|M=6) = .3  \\ &  P(X=8|M=6) = .2  \\ \end{align*} $$ More generically, the PMF is like P(X=M)=0.5, P(X=M+1)=.3, P(X=M+2)=.2, zero otherwise.  Now consider the likelihood form of this, where the data is given as the fixed value X=5 and the parameter $M$ is what varies: $$ \begin{align*} &  P(X=5|M=3) = .2  \\ &  P(X=5|M=4) = .3  \\ &  P(X=5|M=5) = .5  \\ \end{align*} $$  So in the PMF case the shape is (.5,.3,.2),  whereas in the likelihood case the shape is (.2,.3,.5).  There is no single constant that can make these equal.  What is my mistake?


–verb (used without object) Digital Technology.   15.   to send a text message: Texting while driving is an accident asking to happen.   Can I use:        I text to her but she didn't text me back.   I will text on your facebook later.      What about the simple past and past participle forms? Is it text, text, text?


Seeking an appropriate antonym to the word Miracle

Miracles are rare beneficial events that appear to have a supernatural intervention.  So might not the antonym in one word be tragedy? Of the dozens of other words suggested, tragedy for me expresses the most cataclysmic nature of the event:  NOT apocalypse, catastrophe, cataclysm, disaster, debacle or freak incident, though the last probably best describes tragedy as an antonym to miracle.


I don't want it to rain in my world, it is annoying and I always have to type /toggledownfall.  Can someone please tell me how to make it so that it doesn't rain unless I want it to? Like if I would like it to rain, I would do /toggledownfall so that it rains, but I want it to not start raining naturally.  How can I stop rain in my world forever unless I want it to?


Can water pressure ever be high enough to trap gas bubbles or keep them from surfacing?

Can water pressure ever become high enough to trap gas bubbles and/or keep them from surfacing?


how to prove this extended prime number theorem?

A Generalized Prime Number Theorem?  Conjecture  Let $n$ and $k$ be positive integers with $n - 50 > k^2 > 0$ and $n$ sufficiently large. Then for the odd primes we have, when $p$ is the biggest odd prime $\le n$,  $$ 3^k + 5^k + 7^k + 11^k + ... + p^k \sim \frac{n^{k+1}}{(k+1) ( \log(n) - \log(k) ) } $$ I wonder if you guys have seen it before ?  How to prove it ?  Any useful references for $k > 1$ ?


Drawing a figure with concentric circles with text and shading

I am trying to draw the below given figure. Please help me to plot it in Tikz. I am only able to plot concentric circles. . I would like to have different colors in between different circles. Also, the text should be along the curve. The arrow in between the two concentric circles does not have to overlap with the circle on the right hand side.  I would be grateful if you could help me in plotting this in Tikz. Please let me know if you need more information. Thanks!  \documentclass[conference]{IEEEtran}  \ifCLASSINFOpdf  \else  \fi  \usepackage[usenames,dvipsnames]{color} \usepackage[T1]{fontenc} \usepackage{tikz} \usetikzlibrary{positioning} \usetikzlibrary{arrows} \usetikzlibrary{shapes.multipart} \usepackage[caption=false]{subfig} \usepackage{tabularx,tikz} \usepackage{graphicx} \usepackage{color} \usepackage{pdfpages} \begin{document}  \title{Practice Tex}   \maketitle  \section{Introduction}  \begin{figure} \begin{center} \begin{tikzpicture}     \draw(0,0) circle (0.4cm)   node[draw=none,sloped,above]{cxvzxcv};         \draw(0,0) circle (0.75cm) node[draw=none,sloped,above]{ratio};    \draw(0,0) circle (1.25cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,2.2) {22};    \draw(0,0) circle (2cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,3.8) {33333};    \draw(0,-9) circle (0.4cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-9) {fsgsdgf};      \draw(0,-9) circle (0.75cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-7.8) {fgdsfg};    \draw(0,-9) circle (1.25cm) node[midway,sloped] at (0,-9) {dfsdfad};    \draw(0,-9) circle (2.8cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-6.4) {dfsdfsd};    \draw(0,-9) circle (3.2cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-6) {dfsdfsd};    \draw(0,-9) circle (3.6cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-5.6) {sfdsfd};    \draw(0,-9) circle (4.4cm);   \node[draw=none,align=center, font=\scriptsize,text width = 1.25cm] at (0,-4.8) {sdfsf};     \pgfsetlinewidth{3pt}    \draw [-implies][->] (0,-4) -- (0,-4.6);   \end{tikzpicture}  \end{center} \end{figure} \end{document}


If f(x) =  0 if x is R \ Q  = 1/q if x = p/q; p,q belong to Z, g =/= 0, (p, q) = 1  Is f Riemann integrable on [0, 1]?


I am running an instance of Grafana on my machine. It is open on port 3000. But instead of having to type 1xx.x.x.x:3000 can I configure this to be my-grafana.com? I have no idea what I would even search to accomplish. Thanks to all of those who reply in advance.


Changing arrowheads size in pgfplots axes

I need to change the default axes arrowheads size of pgfplots when using the option axis lines=center. Following , I tried this code:  \documentclass{standalone} \usepackage{pgfplots} \usetikzlibrary{arrows, decorations.markings}  \begin{document} \begin{tikzpicture} \tikzstyle{myaxis} = [decoration={markings, mark=at position 1 with {\arrow[ultra thick]{latex'}}},                       postaction={decorate}, shorten >=0.4, line width=0.02pt]; \begin{axis}[axis lines=center, axis line style={myaxis}] \end{axis} \end{tikzpicture} \end{document}   but it doesn't work as I would expect, since the axes lines aren't drawn at all.  Could you help me? Thanks,  Luigi


What changes when an Alienist becomes an outsider?

When a character becomes a 10th level Alienist (prestige class), the following change is said to occur (emphasis mine):     Alien Transcendence (Su): A 10th-level alienist, because of long   association with alien entities and intense study of insane secrets,   transcends her mortal form and becomes an alien creature. Her type   changes to outsider. Additionally, she gains damage reduction 10/magic   and resistance to acid 10 and electricity 10. Upon achieving alien   transcendence, an alienist undergoes a minor physical change, usually   growing a small tentacle or other strange feature, such as an extra   appendage, organ, eye, or enigmatic lump. An alienist can hide this   abnormality in a robe or hood, but the alien growth is not under the   alienist's control and sometimes moves, twitches, opens, or otherwise   animates of its own accord. This applies a —4 penalty on Disguise   checks an alienist makes to conceal her true nature. Anyone who shares   an alienist's predilection for study of the Far Realms immediately   recognizes her transcendent nature, and she gains a +2 circumstance   bonus on all Charisma- based skill checks and ability checks when   interacting with such beings. She gains a +2 circumstance bonus on   Intimidate checks involving any other creatures to whom she reveals   her abnormal nature.   So the character becomes an outsider. d20srd describes outsiders as such:     Features      An outsider has the following features.         8-sided Hit Dice.   Base attack bonus equal to total Hit Dice (as fighter).   Good Fortitude, Reflex, and Will saves.   Skill points equal to (8 + Int modifier, minimum 1) per Hit Die, with quadruple skill points for the first Hit Die.         Traits      An outsider possesses the following traits (unless otherwise noted in   a creature’s entry).         Darkvision out to 60 feet.   Unlike most other living creatures, an outsider does not have a dual nature—its soul and body form one unit. When an outsider is   slain, no soul is set loose. Spells that restore souls to their   bodies, such as raise dead, reincarnate, and resurrection, don’t work   on an outsider. It takes a different magical effect, such as limited   wish, wish, miracle, or true resurrection to restore it to life. An   outsider with the native subtype can be raised, reincarnated, or   resurrected just as other living creatures can be.   Proficient with all simple and martial weapons and any weapons mentioned in its entry.   Proficient with whatever type of armor (light, medium, or heavy) it is described as wearing, as well as all lighter types. Outsiders   not indicated as wearing armor are not proficient with armor.   Outsiders are proficient with shields if they are proficient with any   form of armor.   Outsiders breathe, but do not need to eat or sleep (although they can do so if they wish). Native outsiders breathe, eat, and sleep.      For one, I would tend to believe the character is a native outsider at this point, because it not only has ancestors in the material plane, it was born on it. Am I right?  Now, more importantly, what benefits does the alienist gain from becoming an outsider? Here are a few that they could possibly gain:   More HP. If so, are all Hit Dice from previous character levels rerolled as d8, or is it only from that level onward? The same base attack bonus as the Fighter's, along with the extra attacks that come with it. If so, is this for total character levels or only from this level onward? Improved saving throws (if so, by how much?) More skill points (8 + int instead of 2 + int). If so, does the character get skill points from previous levels or is it from that level onward? Darkvision (60 ft / 12 spaces) Impossible to resurrect unless using true resurrection, wish or miracle if not a native outsider (see above) Proficiency with all simple and martial weapons No need to eat or sleep if not a native outsider (see above)


Incompatibility of Tikz Externalize and Pdfpages

I am writing my final thesis and have come to an issue with Tikz an pdfpages. I had this issue before on an earlier work and hoped it would be fixed by using updated packages, but it did not.  My document compiles just fine before I include an external PDF file, in this case its an A4-PDF with my thesis task. Some images and plots in my work are build with Tikz and I use tikzexternalize to limit memory use. As long as all my Tikz images are compiled before I put  \includepdf[pages=-]{ThesisTask.pdf}   in the document, it works fine. However, if I change code in one of my externalized tikz images (and they need to be recompiled), I get an error that the corresponding file could not be compiled.  I know a MWE would be nice, but I wanted to go without, maybe someone knows a good way to work around or fix it right away. If not, I will add an MWE tomorrow.  My workaround in my earlier thesis was to include this pdf at the very last day as very last action. This would still be possible, but its annoying me big time. Thanks.  //edit, I hope this works as a MWE:  \documentclass{article} \usepackage{standalone} \usepackage{pgfplotstable} \usepackage{tikz} \usepackage{pdfpages} \usepgfplotslibrary{external}  \newcommand{\externaldirectory}{ExtFigures/}%for externalisation \tikzexternalize[prefix=\externaldirectory] \begin{document} Here comes my great diagram: \begin{figure}[ht] \centering \input{diag-Releases} \end{figure} And there it is again, this time as PDF %\includepdf[pages=-]{DiagramPDF.pdf}%include this after first compilation add a PDF file with this name to the current folder \end{document}   The diagram looks like this  \documentclass{standalone} \usepackage{tikz} \usepackage{pgfplots} \begin{document} \begin{tikzpicture} \begin{axis}[ axis background/.style={draw=black,line width=0.95pt}, width=10cm, height=4.5cm, ybar, symbolic x coords = {1960er, 1970er, 1980er, 1990er, 2000er, 2010-}, xtick=data, tick label style={font=\footnotesize}, nodes near coords, ymin = -1, ymax = 220, tick align=inside, ylabel={Anzahl}, ylabel near ticks] \addplot[black,fill=blue] coordinates {(1960er,11)(1970er,42)(1980er,53)  (1990er,79)(2000er,128)(2010-,157)}; \end{axis} \end{tikzpicture} \end{document}   Add a folder called ExtFigures to your working directory. Then compile w/o the pdf include line, then with. Until here it should work. Then, delete content of the ExtFigures folder (which causes Tikz to recompile the image) and see the error.


Bottles with balls inside - PHYSIC SIMULATION

I want to create in blender a realistic physic simulation with bottles that have balls inside, first example is created Blender and the second in another 3D software. How to create this simulation in blender? I have to checked the normals, applied all transforms for scale, position and rotation, set Origin > origin to geometry, increasing the Steps per second and Solver Iterations in the Rigid Body World settings (I tried with the maxima 1000 and 100), set collision shape to Mesh and tried 0.4 or 0 as margins and source to final, but doesn't work..., the simulation is a mess...  I have attached here the blend file, Who can help me how to configure the rigid body settings to achieve a realistic result similar with the second example ?  Here it is my blend file:     Who can help me... ?


What's the point of signing "SEE ID" on the back of my credit card?

I remember in college that we were told to not sign the signature strip on the back of the card, but instead to write "SEE ID", meaning see the signature on our driver's license. Is this a valid security practice that I should still be doing?


Can you prove a group element raised to the order of the group is 1 without Lagrange's Theorem?

Using Lagrange's Theorem, it's easy to show that if $G$ is a finite group and $g\in G$, then $g^{|G|} = 1$.  But proving Lagrange's theorem requires defining cosets.  My question is, is there any elementary way to prove this result without using either Lagrange's theorem or cosets? There is an elementary proof of that kind in the abelian case, but I'm asking about the general case.


Ubuntu 12.04 wifi not getting connected, wicd network manager response - No wireless networks found

I have tried connecting to WiFi in my Dell Vostro laptop, distribution is Ubuntu 12.04 LTS. The wicd network manager shows No wireless networks found.     Output of lsusb&&lspci is:  Bus 001 Device 002: ID 8087:8000 Intel Corp.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 0c45:6a04 Microdia
 Bus 001 Device 004: ID 0bda:0129 Realtek Semiconductor Corp.
 00:00.0 Host bridge: Intel Corporation Haswell-ULT DRAM Controller (rev 0b)
 00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 0b)
 00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev 0b)
 00:14.0 USB controller: Intel Corporation 8 Series USB xHCI HC (rev 04)
 00:16.0 Communication controller: Intel Corporation 8 Series HECI #0 (rev 04)
 00:1b.0 Audio device: Intel Corporation 8 Series HD Audio Controller (rev 04)
 00:1c.0 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 1 (rev e4)
 00:1c.2 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 3 (rev e4)
 00:1c.3 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 4 (rev e4)
 00:1c.4 PCI bridge: Intel Corporation 8 Series PCI Express Root Port 5 (rev e4)
 00:1d.0 USB controller: Intel Corporation 8 Series USB EHCI #1 (rev 04)
 00:1f.0 ISA bridge: Intel Corporation 8 Series LPC Controller (rev 04)
 00:1f.2 SATA controller: Intel Corporation 8 Series SATA Controller 1 [AHCI mode] (rev 04)
 00:1f.3 SMBus: Intel Corporation 8 Series SMBus Controller (rev 04)
 06:00.0 Network controller: Broadcom Corporation BCM43142 802.11b/g/n (rev 01)
 07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)
 08:00.0 3D controller: NVIDIA Corporation GF117M [GeForce 610M/710M/810M/820M / GT 620M/625M/630M/720M] (rev ff)


...when construction of the permanent facilities "is" or "are" projected to be complete: which is correct?

The funding need will extend through the year 2020 when construction of the permanent facilities is projected to be complete.   My boss insists I should use are instead of is. I disagree. Any recommendations?


Strange black shading. Cannot fully light mesh. (Cycles)

Here is the viewport in material view.  The node setup is just a PNG texture into a diffuse shader.    And this is in rendered view.  I've tried using environmental lighting as well as a directional light, and while the lit parts become brighter/washed out, the darker parts stay dark.  Normals are correct and there is no z-fighting.  Ambient Occlusion is not enabled.  Changing to Flat shading makes it worse.    Update:  Any modifier that alters the mesh (bevel, subdivide, etc) make the problem go away instantly.


Allow (to) + infinitive, substantive, verb+ -ing

In which way can the verb 'allow' be used? There is always some confusion and apparently it's often intuitively used wrongly. Which form corresponds to correct English, eventually depending on context (see below)?  1: allow + to + infinitive: It allows to do something. 2: allow + verb+ -ing: It allows doing something. 3: allow + pronoun + to + infinitive: It allows me to do something. 4: allow + pronoun + verb+ -ing: It allows me doing something. 5: allow + noun: It allows something, 6: allow + noun + verb: It allows something to be done.


Is it in general? $[\Lambda,\Omega]=i\hbar\{\lambda,\omega\}_{x,p}$

In R. Shankar's book, He has written $$[X_i,P_j]=i\hbar\{x_i,p_j\}=i\hbar$$ Is there any specific reason to use the Poisson bracket? Is there any general relation which looks like? $$[\Lambda,\Omega]=i\hbar \{\lambda,\omega\}_{x,p}$$


Gzip Mutliple files using single command

Want to Gzip my all the .csv files into a gzip file.  I am using this command.  gzip *.csv;   Problem File contains '//' in its name that's why command is giving error.  Error : - '//File.csv' is not a directory or file.  So please suggest me what ways i can do this successfully.  one solution i thought.  gzip '//File1.csv' '//File2.csv' '//File3.csv'   Please suggest me if this is the right way to perform the same.


Notify/contact SEDE user of fix to query

I guess I'm asking for comments, with subsequent notifications, to be added to queries in SEDE, so we can point out [fixes]  to flawed queries, especially when [the query]  has a comment in it explaining the problem.


Java skips the while statement and goes straight to the end

This is my first semester doing computer programming and our professor totally bailed on us mid class. But I managed to nearly complete the classwork but for some reason my while statement is getting skipped.  import java.util.Scanner; import java.text.DecimalFormat;  public class Election {     public static void main (String[] args)         {              DecimalFormat f = new DecimalFormat("##.00");              float votesForPolly;              float votesForErnest;              float totalPolly = 0;              float totalErnest = 0;              String response;              int precinctsforpolly = 0;              int precinctsforernest = 0;             int precinctsties = 0;              Scanner scan = new Scanner(System.in);             System.out.println ();                   System.out.println ("Election Day Vote Counting Program");             System.out.println ();               do             {                    System.out.println("Do you wish to enter more votes? Enter y:n");                 response = scan.next();                 //this is where it skips from here*********                 while (response == "y")                 {                     System.out.println("Enter votes for Polly:");                     votesForPolly = scan.nextInt();                     System.out.println("Enter votes for Ernest:");                     votesForErnest = scan.nextInt();                      totalPolly = totalPolly + votesForPolly;                     totalErnest = totalErnest +  votesForErnest;                      System.out.println("Do you wish to add precincts? Enter y:n");                     response = scan.next();                     if (response =="y")                     {                            System.out.println("How many precincts voted for Polly: ");                         precinctsforpolly = scan.nextInt();                         System.out.println("How many precincts votes for Ernest: ");                         precinctsforernest = scan.nextInt();                         System.out.println("How many were ties: ");                         precinctsties = scan.nextInt();                      }                 }             }             while (response == "n");             //to here*********************************************             System.out.println("Final Tally");             System.out.println("Polly received:\t " + totalPolly + " votes\t" + f.format((totalPolly/(totalPolly + totalErnest))*100) + "%\t" + precinctsforpolly + " precincts");             System.out.println("Ernest received: " + totalErnest + " votes\t" + f.format((totalErnest/(totalPolly + totalErnest))*100) + "%\t" + precinctsforernest + " precincts");             System.out.println("\t\t\t\t\t" + precinctsties + " precincts tied");          } }


Typing on open start menu doesn't search the menu any longer

I updated my Windows 10 via:  2020-01 Cumulative Update for Windows 10 Version 1909 (KB4532695) and 2020-01 Cumulative Update for .NET Framework 3.5 and 4.8 (KB4534132)  Before the update, when clicking on the Windows start button in the bottom left corner, I could just start typing in anything and it would search through the Program Files etc., for example: Click on the Windows logo, type in update, and it would show "Windows Update".   Now, after the update, when I click on the Windows logo and start typing, it moves over to what looks like Cortana, and no matter what I type in it doesn't seem to search, and it doesn't show anything other than the box itself.   How do I restore the original search function when clicking on the Windows logo, without having to remove the new updates?


Why after that I lost SSH connection during an installation I obtain this "Could not get lock /var/lib/dpkg/lock - open" error message?

I am not so into Linux and I have the following problem.  I was installing RedMine on a remote Ubuntu Server via SSH, following the official tutorial:   The installation process is pretty simple but when I was performing this statment:  sudo apt-get install redmine redmine-mysql   I lost connection...so I come back into my server reconnecting to it...so I perform again this command but now I am obtaining this error message:  *** System restart required *** Last login: Fri Nov 11 11:57:11 2016 from 91.253.121.46 root@Betrivius-VPS:~# apt-get install redmine redmine-mysql E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it? root@Betrivius-VPS:~#   Reading online it seems that it means that the prvious installation process is not ended.  So I don't know if I can retrieve it in some way or abort it. When I log into my remote server appear the message System restart required. I don't know if this message is causated by this situation or not and I don't know if restart my server will solve this issue.  So what is the best solution for this problem?


Find a plane that passes through a point and is perpendicular to 2 planes

Find an equation of a plane that passes through $p(1,5,1)$ and is perpendicular to planes $2x+y-2z = 2$ and $x+3z=4$.  I basically need the 2 other points to make the vector and perform the cross product.  Since $ax+by+cz+d=0$ is the form of a plane. Can I obtain the points as $(a,b,c)$ of the 2 planes given? Also, how can I set them up to obtain the points?


Installation of Windows 10 alongside Ubuntu 16.04 LTS (32 bits) (Windows after Ubuntu)

I have Ubuntu 16.04 LTS (32 bits) installed in my Laptop (Lenovo Ideapad 300) and want to make a dual boot with Windows 10. The reason is that I need to use a software (Clip Studio Paint) which only works in Windows. I know about Wine but I don't want to take risks that prevent a full functionality of the program. The partition table that I have now is MBR.  I have done quite research on the Internet but did not find a specific tutorial for this. So, here is what I know, including the information  received here from the previous version of the question:   I could change to GPT partitioning and install Windows 10 in UEFI mode. In order to do that, without losing Ubuntu, this post may be useful (I have not tried it):  I could conserve the MBR partitioning and instead install Windows 10 in BIOS mode. For that I should create the bootable media for Windows with a tool that allows to boot it in BIOS mode. The best option coud be Rufus, following @RodSmith.    Advantages of choosing UEFI installation are cited in the answer given by @RodSmith and the corresponding comments. Since I am not a tech expert, I am by now considering the other way because it spares me of some risk associated to formatting the disk.


Java NullPointerException for a database Insert statement

Why does this code cause a NullPointerException?  ArrayList<OrdersAttr> ls = new ArrayList<OrdersAttr>(); OrdersAttr myOrder = null; String connString = ConnStr.connString; String connString2 = ConnStr.connString2;  Connection conn = null; Connection conn2 = null; Statement stmnt = null; Statement stmnt2 = null; String selectString = null; String insertString = null; String insertString2 = null; String updateString = null; int orderId = 0;  conn = DriverManager.getConnection(connString); stmnt = conn.createStatement();  selectString = "SELECT A.ORDERID AS ORDERID FROM APP.ORDERS a, APP.CUSTOMER b WHERE ORDERSTATUS = 'NEW ORDER' AND " + " branchid=" + branchid + "and a.CUSTEMAIL = b.EMAIL";  ResultSet rs = stmnt.executeQuery(selectString); while (rs.next()) {     orderId = rs.getInt("ORDERID");     myOrder = new OrdersAttr();     myOrder.id = rs.getInt("ORDERID");     myOrder.date = rs.getString("datetime");     myOrder.orderitems = rs.getString("orderitems");     myOrder.orderquantity = rs.getString("orderquantity");     myOrder.ordersizes = rs.getString("ordersizes");     myOrder.address = rs.getString("floor_f") + " "         + rs.getString("building_f") + " "         + rs.getString("street_f") + " "         + rs.getString("area_subdivision_district_f") + " "         + rs.getString("city_f");     myOrder.name = rs.getString("firstname") + " " + rs.getString("lastname");     myOrder.status = rs.getString("ORDERSTATUS");     myOrder.contact = rs.getString("CONTACT");      conn2 = DriverManager.getConnection(connString2);     stmnt2 = conn2.createStatement();      insertString = "INSERT INTO APP.ORDERS VALUES ('" + myOrder.id + "','" + myOrder.date + "','" + myOrder.orderitems + "','" + myOrder.orderquantity + "','" + myOrder.ordersizes + "','" + myOrder.status + "')";     insertString2 = "INSERT INTO APP.CUSTOMER VALUES ('" + myOrder.id + "','" + myOrder.name + "','" + myOrder.address + "','" + myOrder.contact + "')";      stmnt2.executeUpdate(insertString);     stmnt2.executeUpdate(insertString2);      updateString = "UPDATE APP.ORDERS SET ORDERSTATUS = 'SENT TO LOCAL BRANCH'";     stmnt.executeUpdate(updateString); }   The UPDATE String is executed and it updates the database, but why does it return a NullPointerException and doesn't execute the INSERT statements? Could someone please help me with this problem.


Adding files to java classpath at runtime

Is it possible to add a file (not necessarily a jar file) to java classpath at runtime. Specifically, the file already is present in the classpath, what I want is whether I can add a modified copy of this file to the classpath.  Thanks,


Table with Booktabs - Cannot obtain desired result

This question is related to this post (accepted answer):  .  After compiling the code below I obtain this outcome:   I have tried several alternatives such as adding backslashes or "&" symbols but I am still unable to obtain the desired results.    Thanks in advance.   \documentclass[a4paper,12pt]{scrreprt}     \usepackage{booktabs}      \begin{document}     \begin{table}     \centering     \begin{tabular}{@{} lcccc @{}} % suppress vertical whitespace at start and end     \toprule     Company& \multicolumn{3}{c}{Exceedances} & No.\ of Obs.\    \cmidrule(lr){2-4}     & \multicolumn{2}{c}{Empirical} & Expected\    \cmidrule(lr){2-3} \cmidrule(lr){4-4}     &standard & standardized\\    % make columns 2 and 3 narrower     &normal   & Student's-$t$\    \midrule     Company 1&1&5&9&13\    Company 2&2&6&10&14\    Company 3&3&11&15\    Company 4&4&8&12&16\    \midrule[\heavyrulewidth] % use "thick" \midrule instead of \bottomrule     \multicolumn{4}{@{}l}{\footnotesize An additional hint about a detail}     \end{tabular}     \caption{Here is the caption.}     \label{labelhere}     \end{table}      \end{document}


Feb 24 15:54:34 ns1 named[20308]: all zones loaded Feb 24 15:54:34 ns1 named[20308]: running Feb 24 15:54:34 ns1 systemd[1]: PID file /var/run/named/named.pid not readable (yet?) after start. Feb 24 15:56:03 ns1 systemd[1]: named.service operation timed out. Terminating. Feb 24 15:56:03 ns1 named[20308]: shutting down Feb 24 15:56:03 ns1 named[20308]: stopping command channel on 0.0.0.0#953 Feb 24 15:56:03 ns1 named[20308]: exiting   I have tried renaming to named.service as mentioned here:


How has the definition of gravitational potential energy been derived?

The definition of gravitational potential energy is - The gravitational potential energy of an object at a point above the ground is defined as the work done is raising it from the ground to that point against the gravity . How has this definition been derived?I think this definition has been derived by using the formula Work Done=Force*Displacement . But I don't know how to do this . can someone explain this derivation? Also,  Why can't we define gravitational potential energy like this - The gravitational potential energy can be defined as the amount of work done to lift an object of mass,m to a height,h with acceleration A such that A>g in terms of magnitude? (g=gravitational acceleration)why is this definition wrong?


Ubuntu 16.04 - Apt-get is broken - after a fresh Mysql installation

I'm getting dpkg: error processing package mysql-server-5.7 but mysql-server-5.7 package is working and I am able to login to the DB and chagned the password. But every time I run apt-get I am getting errors. This is a new server  Any suggestion on how to fix this? Since this is a new installation I can repair mysql if needed. I won't be able to deal with it once I load the data into mysql DB.  root@hostname:~# apt-get install htop Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed:   htop 0 upgraded, 1 newly installed, 0 to remove and 251 not upgraded. 2 not fully installed or removed. Need to get 76.4 kB of archives. After this operation, 215 kB of additional disk space will be used. Get:1 http://us.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 htop amd64 2.0.1-1ubuntu1 [76.4 kB] Fetched 76.4 kB in 0s (151 kB/s) Selecting previously unselected package htop. (Reading database ... 63166 files and directories currently installed.) Preparing to unpack .../htop_2.0.1-1ubuntu1_amd64.deb ... Unpacking htop (2.0.1-1ubuntu1) ... Processing triggers for mime-support (3.59ubuntu1) ... Processing triggers for man-db (2.7.5-1) ... Setting up mysql-server-5.7 (5.7.30-0ubuntu0.16.04.1) ... Renaming removed key_buffer and myisam-recover options (if present) mysql_upgrade: Got error: 1045: Access denied for user 'debian-sys-maint'@'localhost' (using password: YES) while connecting to the MySQL server Upgrade process encountered error and will not continue. mysql_upgrade failed with exit status 11 dpkg: error processing package mysql-server-5.7 (--configure):  subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server:  mysql-server depends on mysql-server-5.7; however:   Package mysql-server-5.7 is not configured yet.  dpkg: error processing package mysql-server (--configure):  dependency problems - leaving unconfigured Setting up htop (2.0.1-1ubuntu1) ... No apport report written because the error message indicates its a followup error from a previous failure.                                                                                Errors were encountered while processing:  mysql-server-5.7  mysql-server E: Sub-process /usr/bin/dpkg returned an error code (1)   apt list --installed | grep mysql  WARNING: apt does not have a stable CLI interface. Use with caution in scripts.  mysql-client-5.7/xenial-updates,xenial-security,now 5.7.30-0ubuntu0.16.04.1 amd64 [installed,automatic] mysql-client-core-5.7/xenial-updates,xenial-security,now 5.7.30-0ubuntu0.16.04.1 amd64 [installed,automatic] mysql-common/xenial-updates,xenial-updates,xenial-security,xenial-security,now 5.7.30-0ubuntu0.16.04.1 all [installed,automatic] mysql-server/xenial-updates,xenial-updates,xenial-security,xenial-security,now 5.7.30-0ubuntu0.16.04.1 all [installed] mysql-server-5.7/xenial-updates,xenial-security,now 5.7.30-0ubuntu0.16.04.1 amd64 [installed,automatic] mysql-server-core-5.7/xenial-updates,xenial-security,now 5.7.30-0ubuntu0.16.04.1 amd64 [installed,automatic]


Apps won't install (silently fail after 100% downloaded)

I have a problem with installing apps from Google Play onto my Samsung Galaxy S Plus phone.  It has Android 2.3.6. Yesterday I tried to download some apps. When I clicked 'Install', the app began to download but when it got to 100% it just disappeared and silently failed to install on my phone :\  I don't have an SD card and up to now I saved all my apps on the phone and had no problems like this. It seems to be some settings problem, but I don't know what to do. any ideas?!


How can I add an UI widget for a group input?  Example: Physics > Smoke > Smoke Groups    How can I create such a field in a panel with a python script?


Here's a solution (to the exercise "prove that if $X$ is a space with more than one element, and is normal and connected then $X$ is uncountable"):   by Urysohn's lemma, given $A$ and $B$, closed and disjoint in $X$, there exists a continuous function from $X$ into $[0,1]$ such that $f(A)={0}, f(B)={1}$.   If $X$ were countable, so it would be $f(X)\subset [0,1]$; choose $r\in (0,1)\setminus f(X)$, then $X=f^{-1}([0,r))\cup f^{-1}((r,1])$, so $X$ is disconnected.  But the full power of the lemma wasn't used, all that was used is that there exists a continuous function $X\longrightarrow [0,1]$, so the condition of being normal seems too much.  So my question is, what are the weakest conditions on $X$ for the existence of such continuous functions into $[0,1]$ (or $\mathbb{R}$, for that matter)?


If all the premises are true and the conclusion is false, is it possible for the argument to be logically valid?

Where an argument is logically valid "if and only if it is not possible for the premises to be true and the conclusion false."  Are there any examples of a logically valid argument where the premises are all true, but the conclusion is false? Or is such an argument automatically logically invalid?   Is there any way for the statement "If all the premises of an argument are true and the conclusion is false, the argument is logically invalid" to be false?


'Abstract noun' is defined by  as follows:     A noun denoting an idea, quality, or state rather than a concrete   object, e.g. truth, danger, happiness.   Are abstract nouns always singular? Or are there such things as 'plural abstract nouns'?  Do any of these qualify as 'plural abstract nouns'?     We all want to see this criminal get his just deserts.      Levels of earnings are still rising.      There's a chance it could rain, but odds are that it'll be sunny tomorrow.      The judge awarded her $5,000 in damages.       Please accept my condolences.      When it comes to men, she prefers brains over brawn.       No guts, no glory   EDIT  In no way am I asking about these specific nouns, as the title clearly indicates. So please take these nouns simply possible examples of plural abstract nouns (if there are such things), and try to answer the general question about the existence of plural abstract nouns.


This question from this site seems to be a SO question:    Unfortunately, it is all translated to my language so I couldn't search for the origin question. All the users are changed to Vietnamese names completely. I mean completely native Vietnamese names, not just the translated names.  I just want to report this.


Aspire one 722 graphics driver installation boots and freezes to blank screen?

Acer Aspire 722 - Dual boot with Ubuntu 12.04 inside windows 7.   As I have updated my Ubuntu 12.04 and installed the restricted hardware (graphics) drivers, the system boots and freezes to a blank screen.  A hard reset is the only option to reboot.


How many reopen _votes_ do we have per day?

This question is not about the reopen reviews, from which we have 20 (in the improbable case of a review queue size > 1000, we would have 40). This question is not about the close votes (from which we have 24, except SO where we have 50), and also not from the close reviews, from which we have 20 (if the queue size >1000, we have 40). Although it seems possible that the reopen votes are handled similarly to the close votes, there is no guarantee for that.   Although most of the reopen votes are cast in the frame of a reopen review, it is not always the case. As we know, reopen votes can be cast also from any reopen view independently. It is not clear, how many time is it possible. I suspect, it could have a similar limit as we have with the close votes.  How many reopen votes do we have per day?


Apple devices - "Vibrating feel" when charging

I am absolutely not experienced when it comes to electrical stuff at all which is why I hope you can help me out on this one because I am a bit worried right now.  I own a bunch of Apple devices and after making the switch to a new 2017 MacBook Pro I noticed a weird, vibrating feel when striking over the aluminum. I instantly thought that it has to be related to the device being charged right now and indeed: Depending on whether it's charging or not and depending on the shoes I am wearing I can feel this weird, vibrating, tingly feeling.  So, to underline the fact that I have absolutely no clue about any of that I hope that anyone in here feels like giving me a hand and explain to me what I am experiencing here. I am indeed worried because apparently that applies to all of my current Apple devices - The same happens when I use my non original charger (with 24W) on my iPad.


How to prove that $\frac{\sin \pi x}{\pi x}=\prod_{n=1}^{\infty}(1-\frac{x^2}{n^2})$

How to prove that $$\frac{\sin \pi x}{\pi x}=\prod_{n=1}^{\infty}\left(1-\frac{x^2}{n^2}\right)$$  I tried it with the Taylor series of $\sin(x)$ but I failed.   Is there any help?


For some reason, I'm trying to transfer a simple 0KB file from one system to the next using SCP and it's just hanging at 100%. I've enabled the -vvv flags but still have no idea what this verbose output even means. Here's what it looks like after it hits 100%:  debug2: channel 0: written 23 to efd 6 test.txt                                                                                100%    0     0.0KB/s   00:00 debug2: channel 0: read<=0 rfd 4 len 0 debug2: channel 0: read failed debug2: channel 0: close_read debug2: channel 0: input open -> drain debug2: channel 0: ibuf empty debug2: channel 0: send eof debug3: send packet: type 96 debug2: channel 0: input drain -> closed debug3: receive packet: type 98 debug1: client_input_channel_req: channel 0 rtype exit-status reply 0   I've tried to restart the remote SSH server as well, but that didn't work. It's just running a fresh installation of Kali Linux with no modifications.  Any idea why this may be happening and how to resolve this problem? It's definitely not the client becuse I just uploaded the same file to another system via SCP, but I'm not sure what's going on with the server that would cause this.


I want to ask if that possible to extrude a vertices and connect it in a middle of a plane ?? And If that possible how to do it ? it's my first question and i hope i can find the answer here :D Thanks ..


Static block execution before main method

Does static block of class execute before the main method of same class?   Example:  public class Example {      static     {         System.out.println("hi");     }      public static void main(String[] args) {          System.out.println("bye");      } }   The output of this program is :     hi      bye   My doubt is why the output was not:     bye


Using Refactor fields (Batch processing): error in "Fields mapping" column

I have several layers and want to delete some of their table attributes columns, like FLAG. Using Refactor fields is fine:    However, when I do it in batch, I get an error in the Fields mapping column which doesn't recognize FLAG:  Missing parameter value: Fields mapping (row 1)     I was hoping to use the tool in batch as I have several columns I want to have deleted in many of my layers.


0.05 Result Shows 4 Pennys Instead of 1 Nickel

This is a problem that wants me to read a double value and determine the fewest number of bills and coin needed to represent the amount.   I'm getting a weird result. I put 5.05 as the moneytotal, and I'm getting 4 pennies when it should be 1 nickel.   I think its a rounding issue but I can't see how to change it when it the problem states to use double.           Scanner scan=new Scanner(System.in);          double moneytotal, ten, five, one, quarters, dimes, nickels,  pennies;           System.out.println("Input number!");         moneytotal=scan.nextDouble();          ten= moneytotal % 10;         System.out.println((moneytotal -ten)/10 + " Ten Dollar          Bills.");          five=ten% 5;         System.out.println(((ten - five)/5) + " Five Dollar Bills.");          one = five % 1;         System.out.println((five - one) + " One Dollar Bills.");          quarters = one % 0.25;         System.out.println(((one - quarters)*4) + " Quarters.");          dimes= quarters % 0.10;         System.out.println(((quarters - dimes)*10) + " Dimes.");          nickels=dimes % 0.05;         System.out.println(((dimes - nickels)*20) + " Nickels.");          pennies=nickels % 0.01;         System.out.println(((nickels - pennies) * 100)+ " Pennies.");   Actual result:     input > 5.05   5 Ten Dollar bills. 0 5 Dollar bills. 0 1 dollar bills. 0 quarters. 0 dimes. 0 nickels. 4 pennies.


'Why has it been removed' or 'why it has been removed'?

Would you mind telling me which sentence is correct:  'Why has it been removed?'  From the grammar standpoint, it looks equally to 'Why do you think so?', right?   'Why it has been removed?'   Thank you.


Why would someone buy a way out-of-the-money call option that's expiring soon?

I swing trade equity options every once in a while for fun. This morning I witnessed something I do not understand at all.  In the attached photo, why would someone purchase 6 contracts for .05 at $76.  I just can't wrap my head around this!    Scenario:   Underlying Asset: RY.TSX  Current Price: $71.70 Days to expiry: 4 Days     EDIT: It happened again the next day with 74, see new table with headers as per request:   My only reason for asking is because RY.TSX is the Royal Bank of Canada, this stock will not move multiple dollars in 3 days(expiry in this scenario).  Why buy 10 @ 74 for .04 each instead of just buying 10 @73 for .04 which would have gone through.  If you do the math(excluding commissions): .04 * 100(shares in a contract) * 10 contracts = $40 Stock moves to 74 and they are in the money lets say for .20 .20*100*10 = $200  I just don't see the reward as 99% of the time you will lose this wager, it is just not worth it even if it does happen once in a blue moon.  I can think of much better things to do with $40.  For the skeptics another screen shot to actually confirm this order:


Headphone jack broke and got stuck in headphone socket MacBook Pro

The tip of the headphone jack got stuck in the headphone socket of my MacBook Pro and I have the following question:  The "Sound" option in the System Preferences displays sound output through the "Headphones"  However as the headphone's jack is broken, the headphone doesn't work.  If I pull the headphone out, the "Speaker" icon in the menu bar greys out and sound seems disabled.  If I plug in the headphone in, the "Speaker" icon in the menu bar appears as working however as the headphone itself is broken, there is no sound.  Where I live, it is not possible to buy a micro screwdriver to open the MacBook Pro and push away the headphone jack from the headphone plug.  As a temporary solution I would like to use some AppleScript or other program code to force sound output through the MacBook Pro's speakers instead of the headphones, while the headphones are plugged in.


Error in TeX Live – Font ... not loadable: Metric (TFM) file not found

I freshly installed 'basic' version of TeX Live 2012 (not full, only basic version).  I have following line in my code: \usepackage[T1]{fontenc}  I get following error:  (/usr/local/texlive/2012/texmf-dist/tex/latex/base/fontenc.sty (/usr/local/texlive/2012/texmf-dist/tex/latex/base/t1enc.def) /usr/local/texlive/2012/texmf-dist/tex/latex/base/fontenc.sty:100: Font T1/cmr/ m/n/10=ecrm1000 at 10.0pt not loadable: Metric (TFM) file not found. <to be read again>                     relax  l.100 \fontencoding\encodingdefault\selectfont  /usr/local/texlive/2012/texmf-dist/tex/latex/base/fontenc.sty:100:  ==> Fatal error occurred, no output PDF file produced!   I understand that some packages are missing, however I do not know which ones.  Also, solution to this problem on most of the earlier posts is to install ubuntu latex recommended package, however please note that I am not using LaTeX from Ubuntu's software center (which is old TeX Live 2009) but rather have manually installed basic version of TeX Live 2012 as per instructions here:   Please let me know how do I solve this issue (I don't want to install complete version of TeX Live 2012, only those packages necessary to run this piece of code).


Return child class from overriden method in Inheritance

I've created a base class as follows:      public class BusStopEvent     {         public virtual BusStopEvent CreateEvent(int BusStopNumber)          {             return new BusStopEvent();         }     }   Child class as   public class BusArraival : BusStopEvent {      public override BusArraival CreateEvent(int BusStopNumber)     {         BusArraival evnt = null;         evnt = base.CreateEvent(BusStopNumber);         return evnt;     } }   I'm getting below error:  'BusArraival.CreateEvent(int)': return type must be 'BusStopEvent' to match overridden member 'BusStopEvent.CreateEvent(int)'. Cannot implicitly convert type 'BusTerminal.BusStopEvent' to 'BusTerminal.BusArrival'. An explicit conversion exists (are you missing a cast?)  Why it's showing me this error? Since BusArrival is derived from BusStopEvent, the child object should be compatible with Parent object.


I'm 28, male, and the hair above my forehead started to fall about 2 years ago and my scalp is finally starting to shine out.  I believe this has to do with genetics etc. but still, are there any natural ways to prevent or delay this?


Is there a way to make `man` reflow text when the terminal window is resized?

man apparently uses less -s as the default pager, which does reflow text when the terminal window is resized, but this does not happen in man.  Is there any way of making man reflow text, so that it uses all the space in a resized window which has been made wider? (preferably while still keeping the right margin justification)


(Saw this question in a russian forum and wanted to share it here.)  Was Leo Bonhart a witcher?   He was in early senior age and still got an enourmous speed, strength and reaction.   Non-human fishy eyes. He knew the wolf's school fighting style as he could recognize it from Ciri.  Was able to kill 3 other witchers.     Killed Cahir way to easy and mentioned that Cahir have no chances against him, if he is not a witcher.     Yennefer stabbed a fork in his face. A regular human would loose at least the ability to fight.


C++ - fatal error LNK1120: 3 unresolved externals, can't find solution

So, I'm having problems with my code. I'm simply trying to run an example code to see how it works (I'm a newbie at C++) and this error is appearing everytime I call the List class.  Here's the code:  //main.cpp #include <iostream> #include "List.h" using namespace std;  int main() {     List<char> list;     // 5 types created using a 'for' loop      // and calling the ‘add’ function      for (int i = 101; i <= 105; i++)     {         list.add(char(i));     }     list.display();     // should output a, b, c, d, e      // in this example.     cout << endl;     return 0; }   And here's the List class  //List.h #pragma once #include "Link.h"  template <class F> class List { private:     Link<F>* head; public:     List();     int add(F theData);     void display(); };   and I'll also put List.cpp to help:  //List.cpp #include "List.h"  template<typename F> List<F>::List() {     // 'head' points to 0 initially and when the list is empty.       // Otherwise 'head' points to most recently      // added object head     head = 0; } template<typename F> void List<F>::display() {     Link<F>* temp;// 'temp' used to iterate through the list                   // 'head' points to last object added                   // Iterate back through list until last pointer (which is 0)     for (temp = head; temp != 0; temp = temp->Next)     {         cout << "Value of type is " << temp->X << endl;     } }  template<typename F> int List<F>::add(F theData) {     // pointer 'temp' used to instantiate objects to add to list      Link<F>* temp;      // memory allocated and the object is given a value     temp = new Link<F>(theData);     if (temp == 0) // check new succeeded     {         return 0;  // shows error in memory allocation     }     // the pointer in the object is set to whatever 'head' is pointing to     temp->Next = head;     // 'head' is re-directed to point to the last created object     head = temp;     return 1; }   When I run, It gives me these errors:    PS. I'm using VS2017 btw.  Thank you


I'd like to send stdout from one process to the stdin of another process, but also to the console. Sending stdout to stdout+stderr, for instance.  For example, I've got git edit aliased to the following:  git status --short | cut -b4- | xargs gvim --remote   I'd like the list of filenames to be sent to the screen as well as to xargs.      So, is there a tee-like utility that'll do this? So that I can do something like:  git status --short | \     cut -b4- | almost-but-not-quite-entirely-unlike-tee | \     xargs gvim --remote


Let $X$ be compact Hausdorff, and $C(X)$ the space of continuous functions over $X$. Denote the closed unit ball in $C(X)$ by $(C(X))_1$, then it can be shown $f$ is an extreme point of $(C(X))_1$ if and only if $|f(x)|=1$ for all $x\in X$.  In , we are asked to show that the convex hull of extreme points of $(C(X))_1$ is dense in $(C(X))_1$. By using a theorem of Fejer we can show this is true when $X=[0,1]$. But I do not know how to do it for general $X$.   Since it is only the 7th problem in the first chapter, I am guessing the solution should be elementary.   Thanks!


Hotel doesn't say "No Visitors," but reviews do. What should I do?

I have NEVER in my life stayed in a hotel where it said visitors are not welcome. I am going to NYC, and my friend wanted to visit me, not spend the night. We have done this before at another hotel, but that one was all booked up.  So I made sure I read the policies for the hotel that I booked. It said nothing about visitors or anything at all really, but in two reviews of the hotel they said visitors weren't allowed. I am trying to contact the manager, but apparently the staff have pretty poor English. Can they charge me for my friend visiting? Or not allow him in at all?  I am not asking for anyone to spend the night only for a Visitor.


Is there a way to make a bootable HDD with Ubuntu setup from Windows?  Basically I want to make the same thing as a bootable USB stick, only on HDD. This might sound a little bit useless, but I don't have any other way to boot up my other machine and any preinstalled OS fails to boot.


SQL Server 2008 server cannot connect to itself with alias name or "localhost"

We have a SQL Server 2008 ENT 64bit SP3 server running Server 2008 R2 Standard SP1 64-bit.  This is also a windows/sql clustered environment.  There is the cluster alias for the server, and then we have 2 AD DNS aliases as well for the server  Suddenly I can't connect to the sql instance in Management Studio, or with a Powershell Invoke-SQLcmd IF I am doing it from that actual server, when using one of the dns alias names, or "localhost".  If I use the Cluster alias name it works and if I use the other dns alias name it works.  Using management studio with the non-working dns alias I get "Login failed. The login is from an untrusted domain and cannot be used with Windows authentication."  If I use localhost, I get "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)"    Shared Memory and TCPIP are enabled in SQL Server Config manager but named pipes is not.  But we've NEVER had named pipes enabled, and don't have it enabled on any of our other sql servers and they're set up the same (clustering, dns aliases...etc) and are having no issues.  I've Googled around and had a view people suggest listing what other SQL servers it can see (cmd prompt sqlcmd -L)  If it do it from a good server I see all other servers on my network including the "bad" one.  If I do that command from the "bad" server, I get no results at all.  Pretty much checked everything from this blog and it's all ok except the sqlcmd -L issue I just mentioned above.    Windows firewall is not enabled.  This was working just fine for a couple of years.  I'm not sure when this started happening, but I know that at some point, it was not happening.  And the other kicker...it's only happening locally to this server.  If I connect with management studio or run a powershell Invoke-Sqlcmd from another machine, or my local machine connecting to the "bad" server, it works fine no matter what alias I use.  I'm stumped.  I think it sounds like an issue with the AD alias (there are 2 ad aliases, 1 works locally the other doesn't)...but not being able to connect with localhost makes me question that.  any help is greatly appreciated.


Use of quotes in GNU grep regular expressions

I could see that certain patterns in the GNU Grep can be enclosed within brackets and certain others need not be. For example, matching the beginning of a word works only if it is enclosed within quotes.  user@host:~/Desktop$ grep -E '\<H' test Hello World user@host:~/Desktop$ grep -E \<H test   [test contains the string Hello World]  But matching end and beginning of file works without dollar:  user@host:~/Desktop$ egrep d$ test Hello World   Why is it so? And what is the rule?


Why am I getting "error: type name is not allowed" with these spaghetti templates?

I have the following code with a bit of a "spaghetti" of templates:  template <typename A, typename B, typename... Args> class C {     /*... */     Bar& getBar() { /* ... */ } public:     template <typename U>     static void Foo() {         A a = getA<U>();         Baz& bar = getBar();         bar.frob<U>(a); /* @@@ */     }     /*... */ }  /* no template */ class D : public C<SomeA, D, const SomeE&> { /* ... */ }  /* no template */ class F : public D { /* ... */}   and when I try to compile a function with the following statement:  D::Foo<F>();   I get the error type name is not allowed, on the line marked @@@. Why would I be getting that? I know you get it when you try to call a function with a type name, but it doesn't look like I'm doing it here.


Render scene without rendering transparent background

I am rendering a tracked scene where I added only a shadow catcher ground, and a few storm trooper animations. My PC can render with it's CPU (i5) 16x16 the storm trooper model with motion blur almost the same speed it renders the transparent areas. This causes lots of render time of pointless areas of each frame. (A lot of the transparent areas do have light shadows)    Is it possible to render only the parts where shadows and models exist, and "skip" the transparent areas, or go through rendering the transparent areas quicker?


Bash script to run python script for all images in all subdirectories

I have subfolders in current directory like this:  ls  apples  bananas  oranges  potatoes   Each subfolder includes different number of .jpg images.  cd apples  ls  000000522638.jpg  000000522713.jpg  000000522751.jpg   I have custom python program downloaded from different source which modifies images, and takes input image path and output image path as argument:  python modifyImage.py path/to/input/image.jpg path/to/output/image.jpg   Problem statement:  I want to apply this program for each image in given subdirectories(apples,oranges etc.). There are a lot of folders and images with arbitrary names, so I can not do this by hand. Possible solution would be, firstly finding all *.jpg image paths and send these as argument to python script.  And I made script for updating *.jpg files only in current directory like this   for file in *.jpg do   python modifyImage.py /"$file" /"$file" done   But I need above script to work with subdirectories. Please help.


Does the Martial Adept superiority dice scale up alongside the Battle Master fighter's superiority dice if you acquire the subclass after the feat?

Assume two 1st level Rogues, Alice and Beatrice. Alice gained 3 levels of Rogue and on her 4th level of Rogue, instead of an ability score increase she picked up the Martial Adept feat. She later gained 3 levels in Fighter, and chose the Battle Master archetype. Beatrice gained 3 levels of Fighter, and chose the Battle Master archetype. She then gained 4 levels of Rogue, and instead of an ability score increase she picked up the Martial Adept feat. Alice and Beatrice each now total four Rogue levels and three Fighter levels, obtained via different paths. Is the superiority dice gained from the Martial Adept the same dice for both Alice and Beatrice? (The text above was posted as an example in  that was closed as too broad. After talking to a moderator, it was decided the best thing would be to post the example as a separate question.) The second bullet point of the Martial Adept feat says (PHB, p. 168):   If you already have superiority dice, you gain one more; otherwise, you have one superiority die, which is a d6. [...]   The already have implies that you need to have superiority dice when you acquire the feat, otherwise it is a d6. Beatrice is safe. RAW, she already has superiority dice when she gets the feat. Is Alice stuck with a d6 superiority die for the rest of her career?


Medians of a triangle and the sides of the triangle relationship

Suppose the medians of a triangle are 5,12 and 13 units, find the sides of the triangle. I understand that the medians meet and form centroid. But I am uncomfortable to apply this to this problem


Are there other names for students according to their year - except of "sophomore"?

Today, I've heard my lecturer who turned to us by the word: "sophomores". This the is the first time that I was exposed to this word in the meaning of "student of 2nd year".   My question if there are other names for the 1st, 3rd, 4th, 5th etc. and if all these appellations are common in use?


My render result is very different from my render preview. Does anyone know what I'm doing wrong?


Can someone please explain what actually is a wave?I have read it is disturbance which transfers energy but am unable to get a intuitive feel of it. For example I cannot understand if it is a disturbance why we represent wave by the customary curve resembling sine graph. What does the curve actually represents?


What is the shortest distance between Pyke and Qarth assuming that the world is round in the Game of Thrones?

Is it possible to attack Westeros from Qarth, if one sail to the East? How far is it in the book?  Here's an infographic map:


Query Custom Post Type that doesn't have a specific Custom Taxonomy

I have a CPT 'catalog' and a custom taxonomy 'catalog_category' attached to it.  I need to query for all 'catalog' items, that don't have any values of 'catalog_category' selected.  These arguments make a query for all catalog items.  $args = array(     'post_type' => 'catalog',     'posts_per_page' => -1, );   What arguments I need to add to exclude items with 'catalog_category'?


Solve in $\mathbb{R^{3}}$ : $\begin{cases}x+y+xy=19\\y+z+yz=11\\x+z+xz=14\end{cases}$

Solve in $\mathbb{R^{3}}$ the following system :      $$\begin{cases}x+y+xy=19\\y+z+yz=11\\x+z+xz=14\end{cases}$$   My try but I think not complete :   The system equivalent :   $$\begin{cases}(x+1)(y+1)=20\\(y+1)(z+1)=12\\(x+1)(z+1)=15\end{cases}$$  Then from first equation we have :  $$x+1=\frac{20}{y+1}$$  So third equation give :   $$z+1=3\frac{y+1}{4}$$  Second equation $\implies $   $(y+1)^{2}=16$ then $y=3,-5$   This mean $x=\frac{17}{3}$ or $x=-6$ also $z=3$ or $z=-3$   I'm correct or no ??


Random Number series with a certain range in Java

Using the Well512 random number generator class in Java, how can one generate a random number with a range like 0 to 50?


Does anyone know how to do this without the use of addition rules? We have not covered that in class, and all the info I can find online suggests that as a solution. Thanks]


if $f(x)$ is differentiable at a x, prove that: $\lim_{h\to0}\frac{f(x+h)-f(x-h)}{2h}$

If $f(x)$ is differentiable at x, I need to prove that $\lim_{h\to0}\frac{f(x+h)-f(x-h)}{2h}$ exist and is finite.  so if $f(x)$ is differentiable at a $x$, the difference quotient exist for this point, and also $f(x)$ must be continuous at x as well  so that mean that:  $\lim_{h\to0^+}\frac{f(x+h)-f(x)}{h} =  \lim_{h\to0^-}\frac{f(x+h)-f(x)}{h}$  and that: $\lim_{x\to x_0^+}=\lim_{x\to x_0^-}=f(x_0)$  I know I should probably use arithmetic limit laws to prove this but I can't see how what I figured out could help me. any help with that?  Thanks!


How to skip the intro / splash screen at the start of Kingdom Come: Deliverance

I'm playing Kingdom Come: Deliverance on the PS4, but each time the game starts, it 'introduces' us to the history of the time period the game is set in while loading the menu. It's just 2 minutes, but I'd prefer to skip this if possible, as I don't even spend a second on the menu to continue my game, so it's kind of absurd to wait for 2 minutes listing to the same thing over and over.  Related, but for the PC only:   EDIT: This is for the PS4, so is not a duplicate of


If a group G has only the trivial group and G itself as its subgroup, can we be sure that G has prime order?

It is given that the group $G$ has only two subgroups: the trivial group $\{e\}$ and $G$ itself, can we be sure that $G$ has order $k$ which must be a prime number?   I know that the reverse of this statement is true by Lagrange's theorem, but cannot be sure whether the above statement is true or not.


What are the differences between sudo, su, visudo, chroot, and gksu?

What are the differences between sudo, su, visudo, chroot, and gksu ?


Validating XML using schema, attribute in type elements

I am trying to validate the following XML using a schema.  <?xml version="1.0" encoding="ISO-8859-1"?> <Noticias xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="UXMLS-5.xsd">   <Noticia dia="12" mes="3" año="2004" seccion="Nacional">     <medio tipo="radio">Onda Cero</medio>     <periodista>Fermín Bocos</periodista>     <titular>Atentado bestial en Madrid</titular>     <resumen>Resumen de la noticia Atentado bestial en Madrid</resumen>   </Noticia> </Noticias>   and I am stuck when validating the below line from the above:   <medio tipo="radio">Onda Cero</medio>   I am capable of validating "Noticia", which has attributes, as it isn't a final element with a type associated, I can't when it is the child element with content associated to it though.  I tried many approaches, with not luck so far, also I wasn't able to find a solution online. Any ideas? Am I missing something or is it just not possible doing it?  UPDATE: This is the XSD so far, keep in mind that the "medio" bit is wrong.  <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">   <xs:element name="Noticias">     <xs:complexType>       <xs:sequence>         <xs:element name="Noticia" maxOccurs="unbounded">           <xs:complexType>             <xs:sequence>               <xs:element name="medio" type="xs:string">                 <xs:attribute name="tipo" type="xs:string">                   <xs:simpleType>                     <xs:restriction base="xs:string">                       <xs:enumeration value="radio"/>                       <xs:enumeration value="prensa"/>                       <xs:enumeration value="television"/>                     </xs:restriction>                   </xs:simpleType>                 </xs:attribute>               </xs:element>               <xs:element name="periodista" type="xs:string"/>               <xs:element name="titular" type="xs:string"/>               <xs:element name="resumen">                 <xs:simpleType>                   <xs:restriction base="xs:string">                     <xs:pattern value="[a-zA-Z0-9]{60}"/>                   </xs:restriction>                 </xs:simpleType>               </xs:element>             </xs:sequence>             <xs:attribute name="dia" type="dia"/>             <xs:attribute name="mes" type="mes"/>             <xs:attribute name="año" type="xs:integer"/>             <xs:attribute name="seccion" type="xs:string"/>           </xs:complexType>         </xs:element>       </xs:sequence>     </xs:complexType>   </xs:element>   <xs:simpleType name="dia">     <xs:restriction base="xs:integer">       <xs:minInclusive value="1"/>       <xs:maxInclusive value="12"/>     </xs:restriction>   </xs:simpleType>   <xs:simpleType name="mes">     <xs:restriction base="xs:integer">       <xs:minInclusive value="1"/>       <xs:maxInclusive value="31"/>     </xs:restriction>   </xs:simpleType> </xs:schema>


It is appropriate select and translate best questions and answers from SO in English to post it on SO in Spanish when beta begin

Let me know if this behavior is appropriate on StackExchange.


StackExchange Mobile: Use separate CAPTCHA page

I am on the move a lot and access StackExchange from my mobile device quite frequently. I appreciate the mobile version of the site, but I can't answer any question when it prompts me for a CAPTCHA, because my device is overwhelmed by the amount of content on the page and reboots. Could you please consider making the CAPTCHAs more mobile friendly?


I have two macbooks. I want them to be exact copies. They have different CPUs, RAM, but they have the exact same drives.  I work on both of them. I never work on them simultaneously.  Can I setup something that will update what is new on the one, to the other?  I start doing something on macbook1, I want macbook2 to receive it via somekind of wireless connection.  I have an Airport Extreme, I can setup FTPs and whatever. Both macs will have high speed internet almost all the time.  I don't think DropBox is a solution. I have a lot of data and I don't want it on dropbox. CCC doesn't work bothways it has a source and a destination. Probably there is something with rsync, but is there an automated solution? OSX Server?


I have an input field on a registration screen where the user has to enter his user id which is generally 6 characters long. First 2 characters are always alphabets, and the following characters are mostly numbers. (eg. ab123c or xy5678)  How can I check in the input field with jquery / javascript that user only enters in above format before hitting submit.  <input type="text" maxlength="6" name="uid" id="uid" placeholder="enter user id here">


Bad alignment of Author and Title in Beamer class (Warsaw theme)

I just uninstalled TeX Live 2016 and installed TeX Live 2017 and I noticed that the vertical alignment of author and title in any beamer presentation with Warsaw theme has been disrupted. In this example the author is JESTIN and the title is Beamer Intro. How can I vertical center them?  Moreover, I just found the same bug in the beamer guide obtained writing texdoc beamer in the command prompt, in the part of a warsaw presentation.    Here is my code:  \documentclass{beamer}  \usetheme{warsaw}  \title[Beamer Intro]{Beamer - Introduction to \LaTeX{} presentation making} \author[JESTIN]{Jestin Joy}  \begin{document}  \begin{frame}   \titlepage \end{frame}  \end{document}


Clearly no one has tried to do this but I don't have a windows 8 disc. I do however have a product key and that's all I need. I'm running Ubuntu 14.04 and I've installed the .exe file to download windows 8. I've installed wine and tried many things with wine thing and nothing is working. I need someone to tell me. step by step. how to do this so I can run windows 8 or maybe even 7 again and go on with my life.


How to recursively load all referenced assemblies?

I have an application which takes an argument as the path of some assembly(exe/dll). I need to recursively load all referenced assemblies. I tried to use assembly.GetReferencedAssemblies() method, but it gives only assembly names, not physical paths(Assembly.LoadFrom(path)) (by using assembly name assembly.Load() method doesn't find assembly to load).   How can I proceed this using C# ?


How to see Cycle's material transparency in 3D View

I have two planes with the same node setup, but only one of them is transparent in Material Viewport Shading.    The one that works was created by the Import Images as Planes addon. The other plane was created manually and copying the addon's material setup into a new material.  If I set the addon's material to the "bad" plane it works, so the problem is related to the material itself (nor the object, OPGL or my hardware). I'm working on 2.73.  I have no clue about this behavior,  for checking it out.


How do I fix my minecraft? It says its not executable

The file /home/sean/.minecraft/launcher.jar is not marked as executable.    I get this error whenever I try to load the launcher.jar in my .minecraft folder but then when I right-click, properties, permissions and tick Allow executing file as program it doesn't do anything, doesn't load anything or say anything:     If this was downloaded or copied from an untrusted source, it may be   dangerous to run.  For more details, read about the executable bit.   I got it from .


Is it worthwhile to finish your answer if multiple good answers are given while you're typing yours?

I've been running into something that I find to be an awkward situation on Stack Overflow. That is, when I am typing up what I consider to be a helpful answer and then the message: X new answers have been posted - load these new answers pops up and it is clear that one ore many of these posts answer the question, should I continue with my answer?  If it's a fairly simple question, I usually just discard it, but often times I will have spent a decent amount of time thinking over the answer and debugging the code. It is considered "obnoxious" to basically repeat whats been said if someone has given a very helpful and all encompassing answer?   Also being under 50 reputation, if I have something to in my answer that might improve the code that hasn't been mentioned, but most of my answer is still composed of whats already been said, should I just post it as an answer and remove the repetitive things?  I was just wondering what other users do when this happens.   EDIT:  A similar question can be viewed here:


it's been a while since I'm on Ubuntu and I find this OS much more convenient than Windows! That's why I decided to remove Windows completely my computer :) But I can not do it ... Before when I inserted the key booted with Ubuntu on it and that I chose when starting, it shows me several requests such as "Replace Windows with Ubuntu" (something like this). But since I can not and that's why I ask this question :) Thanks for your quick response!


Determining the order of a finite group of matrices on $\mathbb{Z}_3$

Show that $$G=\left\{\begin{pmatrix}a\ b \\ c\ d\end{pmatrix} : a,b,c,d\in\mathbb{Z}_3, ad-bc\ne 0 \text{ in }\mathbb{Z}_3\right\}$$ is a group with the usual matrix multiplication and $|G| = 48$.   I already proved that it's a group, but I'm bit lost on how to "efficiently" determine the order of such a group (that is, not just listing and counting, I also say this because I'll need some way to determine the cardinality of some larger groups).   At first I looked for some theorem on groups that I've already seen but found none of them to be useful here (surely I must be wrong on this). Then I thought that there are $3^4 = 81$ matrices with entries on $\mathbb{Z}_3$ and then I need to exclude those with $ad=bc$. Any hints to continue on this line? Or for calculating order of groups in general?  Thanks in advance.


Does this give a localization of a ring?

Apologies in advance for the naivety of this question.  Let $R$ be a commutative (resp. non-commutative) ring, $S \subset R$, and let $R' = R[x_s (s \in S)]$ be the polynomial ring obtained by adding a formal variable $x_s$ for each $s \in S$.  Let $I$ be the ideal (resp. 2-sided ideal) generated by {$sx_s-1\ |\ s \in S$}.    Does the quotient $R'/I$ yield the localization $S^{-1}R$ in general?  If not, what if we assume $R$ is commutative and/or $S$ is finite?    EDIT: Thanks to Mariano and Arturo for the quick responses!  Both of their responses say that my construction works in the non-commutative case when $R'$ is replaced with a "non-commutative polynomial ring."  But the Wikipedia article on the localization of a ring states that in the non-commutative case, the localization doesn't exist for all prospective sets of units $S$.  What gives?


Regardless of the purpose, I wonder whether one can redefine $$ by \[ ... \]?


I tried ubuntu 20.04 live usb and its not working. Which version of ubuntu will run in my laptop with persistence storage

My processor is Intel® Pentium(R) CPU N3710 @ 1.60GHz × 4 with 4GB RAM. I tried ubuntu 20.04 but its not running. which version support this spec. which one is better for low specs laptops ubuntu, fedora or mint. I need persistence storage. I tried tail os but its tor browsing is slow, is there any way for normal internet connection in tail os


Let's say that I want to say that I have just turned my pc off.  Which of these sentences is more commonly to be heard?        I have just turned my pc off.   I turned my pc off.


What is the most efficient wood based fuel?

Which form of wood is actually the most efficient in furnaces? I would appreciate if there is a descending list of efficiency.  This includes any thing that can be made from wood, including charcoal though if it requires another unit of fuel to make it, do subtract from its efficiency.   I am aware of the similar question that is the fuel ranking. However, this question is specifically asking for a least-input greatest-output analysis for wood-only materials, to minimize the resource cost of getting efficient furnace fuel.  Its also to resolve a common argument of sticks vs planks and sticks vs crafted alternative.  So as mentioned by Schism, this is a input vs output question.


Statistically comparing 3 groups - Test for statistical difference

I will like to perform and statistical comparison between 3 groups, in order to determine if statistically they are different or not. My data for all of the 3 groups follows a normal distribution. I am aware that in order to test for statistical significance, one can use the t.test function in r; however, that only allows to compare two groups. So, I was wondering if there is test to test such statistical difference in these 3 groups that I have.   So far my code is the following:  groups<- read.csv("...",header=TRUE) head(groups) str(groups) t.test(groups$ï..Group.A,groups$Group.B)    Output of str(groups)  > str(groups) 'data.frame':   20 obs. of  3 variables:  $ ï..Group.A: num  0.16 -1.32 -0.409 0.128 0.844 ...  $ Group.B   : num  0.1673 -0.1368 1.3216 -0.0506 0.1097 ...  $ Group.C   : num  1.852 0.707 0.338 -0.327 1.109 ...   Thank you


Is an entry-level DSLR good enough for portrait photography?

I'm looking into starting a small at home portrait photography business mostly as a hobby for now, and I'm wondering if the camera I have now (Nikon D3000) is good enough for portrait photography.  I've heard from a few friends who do portraits, weddings, etc. that most of the "photo magic" is really just handled in Photoshop, and how the camera is actually used, and the camera is not the only thing to think about.   Is there a flash or some other add-on I should purchase that will help the camera? I just have the onboard one now. I've signed up for a few classes at our local college, however they won't start for a month, so I want to get a head start on what I should look for in equipment.  Is this camera simply sub-par for this sort of work? Is there a better entry level camera I should look into?


Newtonian mechanics and calculus, looking for a good intro book to both together

I am looking for a book on Newtonian mechanics which is very careful to explain why, where and how you need to use calculus to develop physics. Or even, a book which introduce basic notion and propositions of calculus in terms of the latter being necessary to develop Newtonian mechanics.   My interest is partly pedagogical partly philosophical, and I would like to read something with all the subtle points well explained, and as self contained as possble.   Indeed, maybe I am looking to an essays on how to write such kind of book.


I added a robots.txt file to one of my sites a week ago, which should have prevented Googlebot from attempting to fetch certain URLs.  However, this weekend I can see Googlebot loading those exact URLs.  Does Google cache robots.txt and, if so, should it?


Invalid certificate for https://www.*.stackexchange.com

Stack Exchange will do a permanent redirect from www to non www for all Stack Exchange sites. This works fine without SSL but, with SSL the browser will throw an Insecure Connection error due to the certificate doesn't cover the specified domain.  I guess the issue is that the certificate for *.stackexchange.com doesn't cover www.*.stackexchange.com.


How to align the equations that the result be like the image?    \newcommand{\barU}{\bar{U}} \newcommand{\barV}{\bar{V}} \usepackage{amsmath}  \begin{align}     \label{eq:mx2}     \frac{\partial \barU}{\partial t} + \frac{\partial u}{\partial t} &= - \left[\barU\left(\frac{\partial \barU}{\partial x}      + \frac{\partial u}{\partial x}\right)     + u\left(\frac{\partial \barU}{\partial x} + \frac{\partial u}{\partial x}\right) + \barV\left(\frac{\partial \barU}{\partial y}      + \frac{\partial u}{\partial y}     \right) + v\left(\frac{\partial \barU}{\partial y} + \frac{\partial u}{\partial y}\right)\right] - \frac{\partial \barP}{\partial x}      - \frac{\partial p}{\partial x}     + \\     &\frac{1}{Re}\left(\frac{\partial^2\barU}{\partial x^2} + \frac{\partial^2u}{\partial x^2} + \frac{\partial^2 \barU}{\partial y^2} +      \frac{\partial^2u}{\partial y^2}\right) \nonumber     \hspace{8ex}     \mbox{direção x} \\     %------------------------     \label{eq:my2}     \frac{\partial \barV}{\partial t} + \frac{\partial v}{\partial t} &= - \left[\barU\left(\frac{\partial \barV}{\partial x} +      \frac{\partial v}{\partial x}\right)     + u\left(\frac{\partial \barV}{\partial x} + \frac{\partial v}{\partial x}\right) + \barV\left(\frac{\partial \barV}{\partial y}      + \frac{\partial v}{\partial y}     \right) + v\left(\frac{\partial \barV}{\partial y} + \frac{\partial v}{\partial y}\right)\right] - \frac{\partial \barP}{\partial y}      - \frac{\partial p}{\partial y} + \\     &\frac{1}{Re}\left(\frac{\partial^2\barV}{\partial x^2} + \frac{\partial^2v}{\partial x^2} + \frac{\partial^2\barV}{\partial y^2}      + \frac{\partial^2v}{\partial y^2}\right) \nonumber     \hspace{8ex}     \mbox{direção y} \\     %-------------------------     \frac{\partial \barU}{\partial x} + \frac{\partial u}{\partial x} + \frac{\partial \barV}{\partial y} + \frac{\partial v}{\partial y} = 0     \hspace{18.8ex}     &\hspace{8ex}     \mbox{continuidade}   \end{align}


Export QGIS print layout to PDF from script or command line

The "GUI way" of exporting a map to a PDF in QGIS's layout manager is known to be Layout -> Export as PDF .... I wonder if there is any way to do this the CLI way. Either from a python script or the shell. Does anybody know how one would achieve this, especially since QGIS 3.14 added CLI support?


Where should I report trademark infringement or illegal SO clones?

We all love & benefit from SO, and want to help keeping it profitable. How can we help? What counts as trademark infringement:  What is an illegal SO clone:  BTW: I want to report . I think it follows the trademark guidelines, but obviously steals the trademark.


I have 3 questions about installing ubuntu Please help Me.   How much space I have to give to swap partition? My ram is 8GB.  We check two options when installing Ubuntu (one is mp3 fluendo plugin and the other is about restricted extras). Does Ubuntu need internet connection to install them during installation? Is it recommended to have internet connection during installation? Can i download and install everything that Ubuntu downloads during installation later? How?


What checks are in place to prevent high rep users and mods from abusing their privileges?

Since high rep users gain some pretty powerful privileges I wonder what checks and balances are in place to prevent them from abusing their privileges.  I am not near these privileges on any SE site, but a particular user that I think might abuse them is. , demonstrates one way that misuse can be highlighted.  Is that the only thing that prevents bad behavior for high rep users? You have to 'report' them on meta? What if you try to stop them but they 'punish' you, and you can't do anything about it because you are low rep? It would be nice if all their actions were public record; maybe some where on their profile page.  Things that might be done that abuses privileges in my opinion:   Someone may edit questions so they favor his own answer, or disfavor yours because your he does not like your answer. Delete votes on questions (I don't even know what this means) for subjective reasons. Dismiss flags that are valid.   Also, I am a bit confused between a moderator and a trusted user. I know that mods have more power but I would like to see a side-by-side comparison.


Anyone sustain Excel VBA macro deletions due to security software?

I have Excel VBA macros that have disappeared. They still exist, I just can't use them.  See my previous question "" that got no answer so far.  Do security software programs delete/mess with VBA macros - even if they don't tell you?  I am wondering if McAffee anti-virus software could be involved in my problem?  Thanks in advance for your helpful guiding light.  ADD:  VSRawat is exactly right, I see this as a different question which I posed because there was no conclusive answer received on the first question of 'disappearing' macros.    On this current question, I conclude from the answers that no one is having problems with anti-virus/security software gobbling up VBA macros.  Thus I consider this question closed.  My thanks again to VSRawat.


Can I retrieve a re-hashed (hash) value, for instance by additional hashing?

I have a double-SHA-256 of some text $$ h_2 = \operatorname{SHA256}(\operatorname{SHA256}(m)).$$ I don't need the plain text ($m$), but somehow I need to get first $$h_1 = \operatorname{SHA256}(m).$$  Can I have it ($h_1$) by keep hashing the second one ($h_2$)? $$ h_1 = \operatorname{SHA256}(\operatorname{SHA256}(...\operatorname{SHA256}(h_2)...)).$$


How did Molly Weasley make sauce out of nothing if Gamp's Law states that this is impossible?

In Harry Potter and the Goblet of Fire, when the kids and Arthur get to  The Burrow from Privet Drive and Molly is cooking and raging about Fred and George's shenanigans, the following occurs:     Mrs. Weasley slammed a large copper saucepan down on the kitchen table and began to wave her wand around inside it. A creamy sauce poured from the wand tip as she stirred.   In Deathly Hallows, Hermione says that this is not possible:     “Your mother can’t produce food out of thin air,” said Hermione. “no one can.   Food is the first of the five Principal Exceptions to Gamp’s Law of Elemental   Transfigura—”      “Oh, speak English, can’t you?” Ron said, prising a fish out from between his   teeth.      “It’s impossible to make good food out of nothing! You can Summon it if you   know where it is, you can transform it, you can increase the quantity if you’ve already got some—”   So how was Molly causing sauce to pour from her wand, seemingly out of thin air?


$(e_1,e_2,..)$ is not a Schauder basis of $\ell^\infty$

Show that $(e_1,e_2,...)$ is not a Schauder basis of $\ell^\infty$ where $e_i$ is the vector in $\mathbb R^\infty$ with 1 in the ith coordinate and 0 elsewhere and $\ell^\infty=\{(x_1,x_2,...)|x_i\in \mathbb R ~~and ~~ \|x\|_\infty<\infty\} ,\|x\|_\infty=\sup\{|x_1|,|x_2|,...\}$  I am wondering how to prove it and why this statement is true. Actually I think it is a basis since for any given vector $(x_1,x_2,...)=x_1e_1+x_2e_2+...$.  I already proved that $(e_1,e_2,...)$ is a Schauder basis of $\ell^p$ where p>1. I just can't see what changes when it comes to the case of $\ell^\infty$


Surface of revolution is a regular surface

Given $$\alpha : I \rightarrow \mathbb R^2,  \  \ \ \alpha(t)=(\alpha_1(t),\alpha_2(t)) \text.$$ It is a regular space and also homomorphic and $\alpha_2(t)>0$ for all $t \in I$. Let $S$ be the surface in $x$-$y$-$z$-space provided by the rotating the curve $$\{(x ,y ,0 ) \mid x =\alpha_1(t) ,\ y=\alpha_2(t),\ t\in I \}$$ around the $x$-axis. How can I prove that $S$ is a regular surface? All these symbols just got me confused. If you help me to solve this I would very much appreciate it.


Can I use more than one internet provider at the same time?

Usually a home router has only one uplink connection, enabling a single internet provider at a time. But suppose I hack my router (ie. installing linux), could I use 2 internet providers then?


Shouldn’t the sixth “buffalo” in the famous buffalo sentence be in the third person and thus take an “s”?

The famous     Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo.    means:     Buffalo from Buffalo – whom other buffalo from Buffalo bully – bullies buffalo from Buffalo.   So, the sixth buffalo should take an s, and then the sentence is not a that homonym any more!  , a sixth buffalo is taken as plural so that it does not need an s. But the subject of that verb (the sixth buffalo) is the second buffalo and thus is singular. Have we intentionally ignored a rule in the language so to make a homonym?


I read in a book about optical fibers that the different spectral components of a light pulse transmitted in the fiber propagate with different velocities due to a wavelength dependent refractive index. Can someone explain that? Why is that silica refractive index depends on the wavelength/frequency of the wave?


Probability of choosing N out of K correctly from a total population of X

Out of a total population of 50 items, there are 20 "correct" items, what is the probability of me selecting 11 (or more) of these correct items if I randomly choose 20?    How can I do this in R? I was thinking of using binom.test() but that assumes replacement, and my questions involves 'no-replacement' when making your selections.


Return code for curl used in a command substitution

I've script as below :- (edited)  httpUrl="http://www.nnin.com" rep=$(curl -v -X POST -d "UID=username&PWD=pass" $httpUrl)  status=$?   if [ "$?" -eq 0 ]; then      echo "Success"     exit $status   else     echo "Failed"     exit $status fi   when I run the script the return code always $?=0 because in a way the script is successfully execute but I want the return code for cURL to apply in next function.  I've try browsing around and use several method in this site particularly but doesn't help much, maybe because of the POST command and how to prevent the output from print when I run the script?  Thanks