Association of User and Post
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Why does cold metal seem colder than cold air? (I apologize for this elementary question. I don't know much about physics.)  Let's say that I put a metal pot in the refrigerator for several hours.  At this point, I guess, the pot and the air (in the refrigerator) have the same temperature.  Now, I touch this pot. It feels very cold. But when I "touch" the air (that is inside the fridge) it doesn't "feel" as cold. I don't feel the same "ouch!" that I feel when I touch the pot.  Why is that? Why does the metal seem colder than air although they both have the same temperature?  (I know that gas has less particles in it in one unit of volume compared to solids and liquids, but since "temperature" means "the average kinetic energy", these fewer air particles are supposed to hit my hand in a velocity that's going to compensate for their lower number, aren't they?)  A related question, for clarification:  If I use a thermometer to measure the temperature of the pot &amp; air (let's assume it's a thermometer that has a probe that can touch objects), will it show the same reading for both? If so, what makes the thermometer different than my hand? I mean, my hand is sort of a thermometer, so why would it fail whereas a non-human thermometer would work? I use Chrome as my default browser. This includes my browser for work.  We have a trac setup that uses folder paths (see example) for the different projects  Example:   main.employertracsite.com/projects/projectname   I want the ability to manually sort the results that are displayed in the auto-complete.  Chrome displays auto-complete based on the usage history of a web address. Which means that a project that isn't my main focus is displayed in the url instead of the one that I've been using more lately.  Example:   main.employertracsite.com/projects/alliance is the project that I'm not using all the time anymore and is showing up in auto-complete main.employertracsite.com/projects/horde is the project that I am using more often now and want to show up in the auto-complete   I don't want to delete the alliance from my history, but I do want the ability to be able to manually adjust which project shows up in auto-complete. This will be more usable for me in the future because I'm constantly on different projects full-time and they each have their own area.  I also do not want to delete my history. I accidentally closed the window for the verfication code I wanted to create an account for Ubuntu One, but I got impatient when the email with the verification code didn't arrive... I thought I might have typed the wrong address, closed the window and tried again. it told me the address already existed and I just got the code. But since I closed the window I missed it. Is there any way to recover the code? Let $G$ a group with normal subgroups $M,N$ such that $M\cap N=\{e\}$. Show that if $G$ is generated by $M\cup N$ then $G\cong M \times N$. Combine rows / concatenate rows How to prove $\sum\limits_{r=0}^n \frac{(-1)^r}{r+1}\binom{n}{r} = \frac1{n+1}$? I asked  that turned out to have multiple correct answers. How do I pick between them to determine which to accept?  All of the answers were different. They were not the same answer given multiple times. How to import an FBX file into Blender I am trying to import an FBX file from Unity into Blender. Does anybody know how to do that? Enabling CORS in GeoServer (jetty)? It seems that there are many ways to prove the Sylow theorems. I'd like to see a collection of them. Please write down or share links to any you know. Convert file contents to lower case I have temp file with some lower-case and upper-case contents.  Input  Contents of my temp file:  hi Jigar GANDHI jiga   I want to convert all upper to lower.  Command  I tried the following command:  sed -e "s/[A-Z]/[a-z]/g" temp   but got wrong output.  Output  I want it as:  hi jigar gandhi jiga   What needs to be in the substitute part of argument for sed? Need help identifying short story about retired military colonel who fought war at end of time I read this story in an anthology in the eighties or early nineties.  It was about an old man who lived outside a western-like town, though that might have just been how I imagined it.  He goes to town and some ex-military thugs are there causing problems.  Flaunting some odd interdimensional military tech of some sort.  He doesn't want to intervene as doing so would be bad but in the end he must.     By intervening, his military identity is revealed and that causes him (some paradox or causality law) to have to go back and fight the war again.   The war is at the end of time or the universe.  The man is maybe a colonel of the sky something... Not much to go on; I have been searching my collection and wracking my brain for years trying to recall the story. If $m,n\in N$ Prove that there is such a positive integer k, such that $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}$ If $m,n\in N$ Prove that there is such a positive integer k, such that $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}$ I attempted to solve this question using binomial coefficients, saying: $(\sqrt{m}+\sqrt{m+1})^n=\sqrt{k}+\sqrt{k+1}=\sum\limits_{a=0}^n {n\choose a}*\sqrt{m}^{n-a}*\sqrt{m+1}^a$ and from here I was thinking that I had to do something with $\sqrt{m}^{n-a}$ with $\sqrt{k}$ and do something else with $\sqrt{k+1}$ and $\sqrt{m+1}^a$. Unfortunately I couldn't think of what to do with this circumstance. I then thought of maybe taking $(\sqrt{k}+\sqrt{k+1})^2=(\sum\limits_{a=0}^n {n\choose a}*\sqrt{m}^{n-a}*\sqrt{m+1}^a)^2$, but this immediately over-complicated the question. Could you please explain to me how to solve this question and how to solve similar questions in the future? Penalized models can be used to estimate models where the number of parameters is equal to or even greater than the sample size. This situation can arise in log-linear models of large sparse tables of categorical or count data. In these settings, it is often also desirable or helpful to collapse tables by combining levels of a factor where those levels are not distinguishable in terms of how they interact with other factors. Two questions:   Is there a way to use penalized models such as LASSO or elastic net to test for the collapsibility of levels within each factor? If the answer to the first question is yes, can, and should, this be set up in such a way that the collapse of levels and the estimation of model coefficients occurs in a single step? Objective: To separate text column from figures column in every page I don't know if this has been asked before. But so far nothing has come up with my search.  In some books, the figures are placed at the outer side of the page like in the picture below.    Is this achievable in TeX/LaTeX? That is how does one set up the page so that all text will appear in a 'text column' and the figures appear in a 'figures column' in every page? What is the difference in meaning of "frustrated at" and "frustrated with" used in sentences like     He is frustrated with me   or      He is frustrated at me   When is each of these sentences above are used? Three side-by-side tables I am using this LaTeX code to generate three tables side by side. However, it showing errors and not giving satisfactory result. Can anyone please help me to short out the problem.  \begin{table} \centering \makebox[0pt][c]{\parbox{1.2\textwidth}{% \begin{minipage}[b]{0.265\hsize}\centering \begin{tabular}{ | c | c |c | } \multicolumn{3}{c} \hline {$q=1/10$} \\ \hline T &amp; $r_h$ &amp; $\omega$ \\  \hline 0.233 &amp; 0.135 &amp; 2.38486-0.34667I  \\  0.256 &amp; 0.140 &amp; 2.38092-0.35837I \\ 0.273 &amp; 0.145 &amp; 2.38049-0.35982I \\  0.278 &amp; 0.146 &amp; 2.38007-0.36130I \\  0.281 &amp; 0.147 &amp; 2.37964-0.36282I \\  \hline 0.284 &amp; 0.761 &amp; 2.54150-2.03209I \\ 0.285 &amp; 0.765 &amp; 2.54515-2.04292I \\ 0.289 &amp; 0.800 &amp; 2.57799-2.13761I \\ 0.302 &amp; 0.900 &amp; 2.67987-2.40712I \\ 0.312 &amp; 1.000 &amp; 2.79214-2.67552I \\ \hline \end{tabular} \end{minipage} \hfill \begin{minipage}[b]{0.265\hsize}\centering \begin{tabular}{ | c | c | c | } \multicolumn{3}{c} \hline {$q=1/9$} \\ \hline T &amp; $r_h$ &amp; $\omega$ \\ \hline 0.227 &amp; 0.150 &amp; 2.34385-0.41094I  \\  0.245 &amp; 0.155 &amp; 2.34215-0.41723I \\ 0.260 &amp; 0.160 &amp; 2.34056-0.42416I \\  0.271 &amp; 0.165 &amp; 2.33908-0.43175I \\  0.276 &amp; 0.167 &amp; 2.33852-0.43497I \\  \hline 0.280 &amp; 0.720 &amp; 2.50248-1.92299I \\ 0.283 &amp; 0.750 &amp; 2.52893-2.00424I \\ 0.286 &amp; 0.780 &amp; 2.55660-2.08533I \\ 0.289 &amp; 0.800 &amp; 2.57568-2.13931I \\ 0.302 &amp; 0.900 &amp; 2.67807-2.40842I \\ \hline \end{tabular} \end{minipage} \hfill \begin{minipage}[b]{0.265\hsize}\centering \begin{tabular}{ | c | c | c |} \multicolumn{3}{c} \hline {$q=1/8$} \\ \hline T &amp; $r_h$ &amp; $\omega$ \\  \hline 0.246 &amp; 0.180 &amp; 2.29733-0.50611I  \\  0.255 &amp; 0.185 &amp; 2.29654-0.51364I \\ 0.263 &amp; 0.190 &amp; 2.29589-0.52172I \\  0.269 &amp; 0.195 &amp; 2.29534-0.53033I \\  0.273 &amp; 0.199 &amp; 2.29496-0.53758I \\  \hline 0.275 &amp; 0.675 &amp; 2.46067-1.80426I \\ 0.277 &amp; 0.700 &amp; 2.48131-1.87194I \\ 0.288 &amp; 0.800 &amp; 2.57245-2.14170I \\ 0.302 &amp; 0.900 &amp; 2.67555-2.41027I \\ 0.317 &amp; 1.000 &amp; 2.78870-2.67796I \\ \hline \end{tabular} \end{minipage}% }} \end{table} I have a 2015 MBP for work, which I connect my iPhone (6 plus, iOS 10) to charge, and I don't want to trust the computer, ever. However, I must click "Don't Trust" every single time I connect for charging. This is asymmetric to the "Trust" selection, which remembers my decision.  Does anyone know if it's possible to stop the 'Trust/Don't Trust' modal from appearing every time, and have the machine not be trusted?  If possible, can you please tell me how? If not possible, can you please provide proof or evidence that lead you to this conclusion?  Finally, I am not concerned with arguments or opinions about this feature. Only what is outline above. I have been stuck for several days on this old Analysis problem (I am doing some study on my own).  I have tried several things (which I'll indicate below), but I cannot seem to figure it out.  Here is how the problem is presented: Problem: &quot;Let $f$ be a continuous real-valued function on $[a,b]$.  Suppose there exists a constant $M \geq 0 $ such that $$|f(x)| \leq M \int_a^x |f(t)| dt$$ for all $x \in [a,b]$.  Show that $f(x)=0$ for all $x \in [a,b]$.&quot; My Thoughts: I have tried using the mean value theorem iteratively, but that seems to always lead me down a dead end road.  I deduced that $f(a)=0$.  If only $f$ were assumed to be differentiable, then maybe I could play with trying to get the derivative to be $0$, but unfortunately it's only continuous.  My other thought was to (somehow) use the condition to show that $\int_a^b |f(x)| dx = 0$.  I also played around a bit with contradiction, but to no avail.  Even if one of these hair-brained thoughts is correct, I am not really sure what to do next. If you have any ideas, suggestions, or solutions, I would really appreciate it if you are willing to share them.  Thank you for your time. I noticed that I have three warnings when I submitted my Sitemap. They all say this:      When we tested a sample of URLs from your Sitemap, we found that some   URLs redirect to other locations. We recommend that your Sitemap   contain URLs that point to the final destination (the redirect target)   instead of redirecting to another URL.   I'd like to try and resolve this issues but I'm not sure what to do.  Sitemap url for reference: