Story About Carrying Buckets of Oxygen (Old Time Radio) When I was in college, in a small town, there was a radio station in town that would play old time radio shows.  One night I heard one that has stuck in my mind ever since.  While I have a lot of OTR (old time radio) shows in files, most files have air dates and series names, but not show titles, so I'm still working my way through them.  This story had a small family living in an apartment I think they called "The Nest."  Earth was bitter cold by then, cold enough for oxygen to freeze.  (I think that was because the Sun had gone out or, more likely, Earth had left its orbit.)  This family didn't have anything fancy, no hermetically sealed walls or doors, just a LOT of blankets hung all over.  Instead of space suits, they had home made suits they could use for a short while (I think - maybe they had space suits).  They survived by going out, periodically, and scooping up "snow crystals" of frozen oxygen and bringing a bucket full of oxygen like that back to the nest where they could thaw it by the fire (which they had to keep burning continuously for warmth).  I'm working my way through these OTR shows, but I haven't found it yet.  It's also possible this was based on a short story, since a lot of the OTR shows were based on stories in print at the time.  Can anyone tell me the name of the story or who wrote it or anything else to identify it?
Short story about survivors on Earth after the atmosphere has frozen This is a short story I read maybe in the '80s.  Earth has been thrown away from the Sun, probably due to a very large object passing through the Solar System, and the atmosphere has frozen in layers. There is a small family - father, mother, two children, who live in a room they have made airtight by hanging many layers of material to slow the loss of air. They keep warm with a 'camp-fire'. The father goes out every day in a suit of some sort to find food and mine frozen oxygen. It ends when they are found by another, larger group of survivors.  Does anybody know the title and author?
Additive group contains exactly three elements of the set $\{p,p+q,pq,p^q,q^p\}$ How to convert Local time to UTC time in Delphi? and how to convert it back from UTC to local time? At this moment there are 4 meta-site questions on the HNQ list:    (World Building Meta)  (Meta StackOverflow)  (Workplace Meta)  (Mathematica Meta)   When I first saw it, I only saw the SO Moderator question, so I assumed that this was a one-off special thing for the election; but now we've got four questions crept in. Was this an intentional change, or a bug? Aligning equations within multline I have this really long equation and I have used multline to break it up. I also want to align the broken bits of the equation to the left. When I use  align, for some reasons it aligns to the right when I want it to be on the left. How can I align to the left?  \begin{multline} \begin{align} \mathcal{H}_{q1} \mathcal{H}_{q2} \mathcal{H}_{q3}...\mathcal{H}_{qn}0=\frac{1}{2}H_{q1}\{\mathcal{H}_{q2}\mathcal{H}_{q3}...\mathcal{H}_{qn}0\}+\frac{1}{2} h_{q1} \\ =\frac{1}{2}H_{q1}\{\frac{1}{2} H_{q2}[\mathcal{H}_{q3}...\mathcal{H}_{qn} 0]+\frac{1}{2}h_{q2}\} +\frac{1}{2}h_{q1}=\\ \frac{1}{2}H_{q1} \frac{1}{2} H_{q2} [\frac{1}{2}H_{q3}(\mathcal{H}_{q4}..\mathcal{H}_{qn}0)+\frac{1}{2}h_{q3}]+ \frac{1}{2}h_{q2}+\frac{1}{2}h_{q1}=...\\          =(\frac{1}{2^n})H_{q1}H_{q2}H_{q3}..H_{qn}0+ (\frac{1}{2^n})H_{q1}H_{q2}H_{q3}..H_{qn-1}h_{q1}\\+(\frac{1}{2^n})H_{q1}H_{q2}H_{q3}..H_{qn-2}h_{qn-1}+.. \\+ (\frac{1}{2})h_{q1}=\sum^n_{j=1} (\frac{1}{2^j}) H_{qo}H_{q1} H_{q2}H_{q3}..H_{qj-1} h_{qj} \end{align} \end{multline} Suppose k is an integer such that $6k + 1$, $12k + 1$, $18k + 1$ are primes. Show that $n = (6k + 1)(12k + 1)(18k + 1)$ is a Carmichael number. Suppose k is an integer such that $6k + 1$, $12k + 1$, $18k + 1$ are primes. Show that $n = (6k + 1)(12k + 1)(18k + 1)$ is a Carmichael number.  This is a question on a past exam that I find difficulty to answer. Can anyone help? Allow non-bumping minor edits, but review them on /review Suppose that $V, W$ are closed in $X$ and that $V\cap W, V\cup W$ are connected. Show that $V$ and $W$ are connected.  My attempt: Suppose that $V=U_1\cup U_2$ where $U_i$ are open in $V$, not empty and $U_1\cap U_2=\emptyset$. This induces a separation for $V\cap W$: $$ V\cap W = (U_1\cap W)\cup(U_2\cap W).$$  $U_i\cap W$ is open in $V\cap W$  $(U_1\cap W)\cup (U_2\cap W)=\emptyset$ as otherwise $U_1\cap U_2 \ne \emptyset$.  Now, I need to show that both sets are not empty. We know that $V\cup W$ is connected and closed in $X$. So, for all $x\in V\cup W=U_1\cup U_2\cup W$ and all neighborhoods $Z$ (in $X$!) of $x$ we have that $Z\cap (V\cup W) \ne \emptyset$. We can choose $x\in U_1 \subseteq V\cup W$. But then I would have to find a neighborhood of $x$ in $X$. I can't find one... How can I complete this bullet point?   Thanks. Using multiple wildcard parameters with arcpy.ListFeatureClasses I know there has to be a way to do this but I'm having trouble figuring out how to do so. I would like to create a list of feature classes to perform operations on however, I want to have the list contain feature classes which have 2 separate and distinct file name identifiers. The code would look something like:  FCS = arcpy.ListFeatureClasses("X_*" OR "*_Y")   I know OR is incorrect however, is there some way to do this without having to re write code to work with the second wildcard. Thanks for helping gout, i know there is a selection method in the Select By Attributes which allows for multiple wildcard use using the OR statement. Create keyboard shortcuts for touch bar's functions I have broken the touch bar in my MacBook Pro 13". Only the ESC key keeps working.  Replacing the touch bar may be expensive so I'd like to know if it is possible to replace its functions with keyboard shortcuts.  The functions I am highly interested in are:   volume screen backlight keyboard backlight How do I print bold text in Python? MPPT charging a li-ion battery I just designed this MPPT solar charge controller which outputs 4.2 V regulated via MPPT, it uses the SPV1040 IC. This will be used on a satellite with 4 side panels, each with 8 solar cells in parallel outputting 2.6 V at approximately 122 Ma. Each panel will have this exact circuit and all the outputs will be connected in parallel to a 3.7 V lithium ion camera battery.  When active only 1 solar panel will be active and the other MPPT circuits will be offline or providing a very low amount of current. How should I connect the 4.2v to the battery, just directly or using some sort of controller to stop charging at 4.2v? Keep in mind the battery will always have a load and it will charge for around 50m in a 90m cycle due to being eclipsed. I would obviously like the battery to last as long as possible so I am not sure what are the implications of constantly having a battery connected to 4.2 V during 50m. Thanks.   The schematic was made based off a simulation made using the ST Edesignsuite directly from the provider.  Excuse my previous question about this, wasn't properly worded. Modular arithmetic: division, fractions, solving linear congruences i want to compile several pgfplots pictures with lualatex, since it dynamically allocates memory for compiling (in contrast to pdflatex).  In some plots, like my MWE.tex given below, i want to use a contour plot. This is typically done with gnuplot. To compile a document like this i need to use --shell-escape, such that gnuplot command can be executed while compiling the document.  \documentclass[a4paper]{article}  \usepackage[utf8]{luainputenc} \usepackage{pgfplots} \pgfplotsset{compat=newest} \begin{document} \begin{tikzpicture}   \begin{axis}     \addplot3[contour gnuplot]      {x+y};       \end{axis}   \end{tikzpicture} \end{document}   If i use  pdflatex --shell-escape MWE.tex   everything works fine, and the log says something along the lines  This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=pdflatex 2016.6.12)  13 JUN 2016 10:46 entering extended mode  \write18 enabled. .... Package pgfplots notification 'compat/show suggested version=true': document has been generated with the most recent feature set    (\pgfplotsset{compat=1.13}).  \openout3 = `MWE_contourtmp0.dat'.  \openout3 = `MWE_contourtmp0.script'. runsystem(gnuplot "MWE_contourtmp0.script")...executed.   If i use     lualatex --shell-escape MWE.tex i get the following error:  This is LuaTeX, Version 0.95.0 (TeX Live 2016)  (format=lualatex 2016.6.12)  13 JUN 2016 10:52  system commands enabled. ... Package pgfplots notification 'compat/show suggested version=true': document has  been generated with the most recent feature set (\pgfplotsset{compat=1.13}).  Package pgfplots info on input line 10: Using 'lua backend=false' for plot 0 (type 'contour external'): plot handler does not support LUA.  \openout3 = MWE_contourtmp0.dat  \openout3 = MWE_contourtmp0.script gnuplot "MWE_contourtmp0.script"  ! Package pgfplots Error: sorry, plot file{MWE_contourtmp0.table} could not be opened.   The .table file exists and looks identical to the one created by pdflatex, but it says that it cannot be executed.  (I just installed texlive 2016 yesterday, so everything should be up to date.) Switching from one area of graduate study to another? Is it possible to switch from one area of graduate study to another in US universities? For example, suppose someone has enrolled in a computer science phd program. Can he switch over to math(or physics) phd program in the same school later?(or say from applied mathematics to pure mathematics?)  What are the steps for doing for doing that? Styling each feature of a layer individually I’ve a PostGIS table which is published as a Geoserver layer. Every feature in the table has some attributes that should style that feature (e.g color, size, opacity, external graphic url, ... etc).  I can create an SLD document and let it read its styling attributes from the table using &lt;PropertyName&gt;, but the problem is more complex than this, for example: some points features need to be styled as a simple circles, while some other need to be styled as external-graphic images. And from the SLD Reference, the SLD PointSymbolizer must have either &lt;Mark&gt; or &lt;ExternalGraphic&gt; element, for that reason I should create two rules one for the simple point symbolizer and the other for the external-graphic point symbolizer, and should add a filter to each rule so that it deals only with the appropriate features, something like:  &lt;FeatureTypeStyle&gt;     &lt;Rule&gt;         &lt;ogc:Filter&gt;             &lt;ogc:PropertyIsEqual&gt;                 &lt;ogc:PropertyName&gt;is-external-graphic&lt;/ogc:PropertyName&gt;                 &lt;ogc:Literal&gt;0&lt;/ogc:Literal&gt;             &lt;/ogc:PropertyIsEqual&gt;         &lt;/ogc:Filter&gt;         &lt;PointSymbolizer&gt;             &lt;Graphic&gt;                 &lt;Mark&gt;                     &lt;WellKnownName&gt;circle&lt;/WellKnownName&gt;                     &lt;Fill&gt;                         &lt;CssParameter name="fill"&gt;                             &lt;ogc:PropertyName&gt;fill-color&lt;/ogc:PropertyName&gt;                         &lt;/CssParameter&gt;                     &lt;/Fill&gt;                 &lt;/Mark&gt;                 &lt;Size&gt;6&lt;/Size&gt;             &lt;/Graphic&gt;         &lt;/PointSymbolizer&gt;     &lt;/Rule&gt;     &lt;Rule&gt;         &lt;ogc:Filter&gt;             &lt;ogc:PropertyIsEqual&gt;                 &lt;ogc:PropertyName&gt;is-external-graphic&lt;/ogc:PropertyName&gt;                 &lt;ogc:Literal&gt;1&lt;/ogc:Literal&gt;             &lt;/ogc:PropertyIsEqual&gt;         &lt;/ogc:Filter&gt;         &lt;PointSymbolizer&gt;             &lt;Graphic&gt;                 &lt;ExternalGraphic&gt;                     &lt;OnlineResource                xlink:type="simple"                xlink:href="smileyface.png" /&gt;                     &lt;Format&gt;image/png&lt;/Format&gt;                 &lt;/ExternalGraphic&gt;                 &lt;Size&gt;6&lt;/Size&gt;             &lt;/Graphic&gt;         &lt;/PointSymbolizer&gt;     &lt;/Rule&gt; &lt;/FeatureTypeStyle&gt;   My question is: Is there any better solution that is more dynamic? Does a correlation matrix of two variables always have the same eigenvectors? Prove $2^b-1$ does not divide $2^a + 1$ for $a,b>2$ I'm trying to prove $2^b-1$ does not divide $2^a + 1$ for $a,b&gt;2$. Can someone give a hint in the right direction for this? Is there an American English equivalent of the British idiom "carrying coals to Newcastle"? I'm an American living in the Netherlands who is learning Dutch. There's an idiom in Dutch that describes performing a needless/futile activity, "water naar de zee dragen," which literally translates to "carrying water to the sea." My Dutch parents-in-law asked me if there was an English equivalent, but I couldn't think of one.  In doing   , I found that the English translation given for the this idiom is always "carrying coals to Newcastle." This was the first time I'd ever come across the phrase, and subsequent searches revealed that it was indeed of  , though one site I found did . However, neither I nor any of my culturally American friends have ever heard of this phrase.   Is there an American English idiom or phrase that carries the same connotations for carrying out a futile activity? The more I use Stack Exchange, the more it is getting a knowledge-base for me. All questions, that I need for later reference I mark as favorite. Now I need to store these pages locally on my laptop. It is really time-consuming:  I could use Ctrl+S on each favorite question page  on Linux: there could be a solution with wget -N -r -l 1 &quot;https://stackoverflow.com/users/1069083/rubo77?tab=favorites&quot;  this will download all favorite questions but it creates no correct index.html Another approach would be to use the  to automatically follow into all your Stack Exchange-accounts. But that would have to be somehow limited to only favorites links on your  in each stack. cross-platform: You would need a firefox-plugin that downloads links recursively but only within the favorite-area of the  in your stack  Additionally, I would like to  and Ideal of the twisted cubic The twisted cubic is the image of the morphism $\phi : \mathbb{P}^1 \to \mathbb{P}^3 , (x:y) \mapsto (x^3:x^2 y:x y^2:y^3)$, it is given by $X = V(ad-bc,b^2-ac,c^2-bd)$. Now I would like to compute $I(X)$, which equals by the Nullstellensatz the radical of the ideal $I := (ad-bc,b^2-ac,c^2-bd) \subseteq k[a,b,c,d]$. I think that that $I$ is already a radical ideal, even a prime ideal. Namely, I suspect that  $$\phi^* : Q:=k[a,b,c,d]/I \to k[s,t] , a \mapsto s^3, b \mapsto s^2 t , c \mapsto s t^2 , d \mapsto t^3$$ is an injection. If this is true: How can we prove that? I've already tried to find a $k$-basis of the quotient, but this turned out to be a big mess. Even the representation of the quotient as a monoid algebra doesn't seem to help. Another idea is the following: A formal manipulation of generators and relations implies $Q_a \cong k[a,b]_a$. Thus it suffices to prove that $Q \to Q_a$ is injective, i.e. that $a$ is not a zero divisor.