How to quantify the effect of a mediator, SPSS, Psychology experiment

Question: I have collected data to answer the question "Does Neuroticism Mediate the effect of a Mindfulness Intervention?" I Have collected pre-intervention Mindfulness Score and a post intervention measure (both scale). I also took a neuroticism score before the intervention to estimate the level of trait neuroticism (also scale). There was no control group.
So far I have managed to demonstrate with a paired-samples t-test that there is a significant difference between pre and post-mindfulness scores, I have used Pearson correlation to show that mindfulness and neuroticism are negatively correlated at baseline (both of these are a replication of the existing findings).
For the mediator part, I intended initially to use the model from another study which divided the neuroticism score into low, low/medium, medium high and high as a quasi-independent variable. However, the scores in my data were too clustered together without much of a range in the group (there was a high attrition rate ~45%) so these 4 groups are not possible. I have tried running a repeated measures ANOVA, where I dichotomize neuroticism into low/high, which I know is not the best idea as I will artificially restrict the variance in my data. This does however produce quite a sensible looking plot and desirable output for my study but I know it's not sound practice.
I have also tried doing what I think is a repeated measures ANCOVA, with time at 2 levels as a within subjects factor (pre and post-intervention score) and neuroticism as a covariate but I have nothing to put into the between subjects factor so I'm not sure if it's accurate. It is giving neuroticism a value of 3.45 in the model but I have no idea what that number means or how to interpret it. It also produces a sensible looking plot showing the increase in mindfulness pre to post-intervention. I have also tried is computing a mindfulness score difference and correlating that with the level of mindfulness which also gives me a medium size positive correlation <0.05.
Any help would be greatly appreciated as I am really desperate!
Answer: You cannot answer a mediation question with this design, but I'm not sure you want to. It seems like you are more interested in moderation, i.e., does baseline neuroticism affect how effective the intervention is? You can define "how effective the intervention is" as the mindfulness difference score between post and pre. So the question is whether there is an association between baseline neuroticism and this difference score. This is a simple regression or correlation analysis, and there is no need to dichotomize any variables. You can just produce a scatterplot of the difference scores on the y-axis and neuroticism on the x-axis and see how related the variables are using correlation or fit a regression line through the points.
Know, though, that the design of this study is very limited and does not allow you to make any causal conclusions without strong assumptions. I doubt it would be publishable as-is. First, without a control group, you can't say whether the intervention was effective or not; it's entirely possible participants' mindfulness scores would have changed in the same direction in the absence of the intervention, e.g., simply because of the structured time or because of external factors (i.e., maturation). Second, even if you show that neuroticism is associated with changes in the outcome, that doesn't mean neuroticism itself causes those changes; it could be that neuroticism is correlated with a different variable that is actually responsible for those changes. As a pilot study or a class project this is fine; as a study to unequivocally demonstrate the effectiveness and mechanism of an intervention, this is inadequate.
Comment: @Noah: Completely irrelevant but ... You are in Quantitude man! You unlocked not only the dream job but also the dream podcast guest role! :)
Comment: Hey Noah, Thanks for your reply! This is for an undergrad project but, yes I can see how it has some fundamental flaws. My supervisor warned against using a control as getting enough people to sign up was already a problem... I have gone with the correlation analysis now and it seems a lot clearer. Thank you for taking the time, I will hopefully be able to run better research in the future... God knows I have learned a lot from this undergrad project!
Comment: @Nick Good luck! My undergrad thesis in psychology was terrible (not that yours is) but I still made it into a PhD program and eventually into my dream job. You will have good years ahead of you.
Comment: thank you for your kind words, they are a real boost right now in the dark hours of dissertation! I wish you all the best to, you seem like a great guy! Thanks again for taking the time and wish you all the best :)
Comment: Please see
https://stats.meta.stackexchange.com/questions/6304/my-upvoting-policy,
when you find a question sufficiently clear to
write an answer, consider to upvote the question!


How can I subdivide on only one axis?

Question: I'm trying to use a weight-map to put columns of spines on a cactus. I need more vertices for the spines to spawn at on my model, but if I subdivide normally, it will create vertices in between the columns that are close enough to generate spines in the middle, which means I would have to manually modify the weight-map to remove the middle spines. Is there any work-around where I can create more vertices on the columns and not on the rows?
Answer: You can select the specific edges you would like to subdivide whilst in edit mode.
Answer: If you want to remove some loops after a subdivision, it can be relatively easy:
Switch to edit mode, edge select.  Select a ring loop by ctrl alt selecting on an edge:

Use a checker deselect operation to deselect every other edge:

Use select edge loops operation to select the loops from selected edges:

Then dissolve the edge loops:

Note that what is a column and what is a row is not particularly clear cut.  With two edge loops selected, which of those loops is a row and which is a column?

Any mesh with any poles-- which is every manifold mesh-- confuses the question.

How can I subdivide on only one axis?


How to send MAC broadcast data frame with Android AP

Question: I'm trying to use the Android wifi AP functionality to send a MAC broadcast frame that other devices listening within range will be able to pick up. Any ideas how to do this would be greatly appreciated.
Answer: Open a socket a send UDP packet to an IP broadcast address. It will automatically translated to a MAC broadcast address.


Writing a number in polar form (help converting $\theta$ to $\pi$)

Question:
Write $w = \sqrt{3}  - i$ in polar form.

How is $\theta = \frac{-1}{\sqrt3} \textrm{ converted into } \frac{-\pi}{6}$? I understand that $w$ lies in the fourth quadrant of the unit circle, but that's about all I understand. I tried to convert degrees to radians, but I don't think that was the smart decision (I failed).
Comment: Perhaps you mean $w=3-i$?  And $\tan \theta = \frac{-1}{\sqrt{3}}$ implies $\theta = -\frac{\pi}{6}.$
Comment: ah, i meant $w = \sqrt 3 - i$. And how does tan$\theta$ imply that? Where does the assumption come from?
Comment: That's just how functions work.  For example, if $\sin(\theta)= \frac{\sqrt{2}}{2}$ and $\theta$ is in the first quadrant, then the unique solution is $\theta= \frac{\pi}{4}$.  Even simpler: let $f(x):=x^2$.  Then if $x$ is positive, the unique solution to $f(x)=9$ is $x=3.$
Comment: $\theta$ isn't equal to $\frac{-1}{\sqrt{3}}$, $\tan \theta$ is. You have to find $\tan^{-1} (\frac{-1}{\sqrt{3}})$, which is equal to $\frac{-\pi}{6}$. This is basic trignometry.
Comment: It should be pointed out that tan($5 \pi /6$) is also $-1 \over {\sqrt 3}$, but $5 \pi /6$ is not in the desired quadrant
Comment: Where did you get that $\theta = -\frac 1 {\sqrt 3}$.  The statement was $\tan (\theta) = -\frac 1{\sqrt 3}$.
Answer: You should always draw the picture when you try to find the modulus and argument.
In an Argand Diagram, the complex number $x+\mathrm i y$ corresponds to the point $(x,y)$ on the $xy$-plane.
Put the point $(\sqrt 3,-1)$ on the $xy$-plane, and join it to the origin by a chord (part of a line).

You can see the chord joining the origin to the complex number as the hypotenuse of a right-angled triangle. The length of that chord is the modulus $|z|$, which can be found using Pythagoras:
$$|z|^2 = \left(\sqrt 3\right)^2 + 1^2 = 4$$
This gives $|z| = 2$, since $|z| \ge 0$.
The argument is the angle of the chord measures from "3 o'clock", i.e. the positive real axis. Anti-clockwise rotations are measured as positive, while clockwise rotations are measure as negative.
This may seem odd, but right is positive and left is negative on the number line.
We can use basic SohCahToh Trigonometry to find the argument. First, find the angle between the chord and the $y$-axis, then subtract from $90^{\circ}$ or $\frac{1}{2}\pi$ rads to get the angle between the chord and the positive $x$-axis.
$$\tan \theta = \frac{\mbox{opp}}{\mbox{adj}} = \frac{\sqrt 3}{1} = \sqrt 3$$
The angle between the chord and the $y$-axis is then $\arctan \sqrt 3 = 60^{\circ}$ or $\frac{1}{3}\pi$ rads. That means the argument, i.e. the angle between the chord and the positive $x$-axis (remembering that clockwise is negative) is $-\frac{1}{6}\pi$ or $-30^{\circ}$.
Finally, $|z|=2$ and $\arg z = -\frac{1}{6}\pi$, so
$$z = r(\cos \theta + \mathrm i \sin \theta) = 2\left(\cos\left(-\frac{1}{6}\pi\right)+\mathrm i \sin\left(-\frac{1}{6}\pi\right)\right)$$
Comment: the visual helped a lot. How did you draw a graph like that?
Comment: @EvanKim I used the website Desmos. Here's a link to what I did: https://www.desmos.com/calculator/4nvyw6xnav
Answer: The solution to $\tan \theta = \frac {-1} {\sqrt 3}$ is $\theta = \frac {-\pi} 6 + n \pi$.
$\theta = \frac {-\pi} 6$ is a solution in the fourth quadrant, as desired.
Answer: The easiest way to do this kind of conversion is often just to treat it as geometry: plot $x+iy$ as a point $(x, y)$, draw a line joining it to the origin, draw another meeting the $x$-axis at a right angle, and look at the resulting triangle.
In this case it'll be half an equilateral triangle, so you could even do it without trig functions if you wanted.
And if you do use trig functions, the triangle tells you which to use.
Answer: The first thing to realize is that if you ever have $x^2 + y^2 = 1$ then there is a $\theta$ so that $x = \cos \theta; y = \sin \theta$ and $\tan \theta = \frac yx$.
And second thing to realise is that if you have any $a,b$ where they don't both equal $0$, you can rewrite $a = (\sqrt{a^2+b^2})a'$ and $b = (\sqrt{a^2 + b^2})b'$ where $a' = \frac a{\sqrt{a^2 + b^2}}$ and $b' = \frac b{\sqrt{a^2 + b^2}}$ and you will then have $a'^2 + b'^2 = 1$.
Which means there is $\theta$ so that $\tan \theta = \frac {b'}{a'} = \frac ba$, $a' = \cos \theta$ and $a = (\sqrt{a^2 + b^2})\cos \theta$ and $b' = \sin \theta$ and $b = (\sqrt{a^2 + b^2})\sin \theta$.
That means for any $a + bi \ne 0$ so that $a+bi$ is a complex number and $a$ is its "real" part and $bi$ is its "imaginary part", we can write:
$a+bi = (\sqrt{a^2 + b^2})(\frac a{\sqrt{a^2 + b^2}} + \frac b{\sqrt{a^2+b^2}}i)$
and that means there exist a $\theta$ so that
$a + bi = (\sqrt{a^2 + b^2})(\cos \theta + i\sin \theta)$.
If we imagine $a+bi$ as the point $(a,b)$ on a complex plane, this should not be surpising.  $\sqrt{a^2 + b^2}$ is simply the distance from $(a,b)$ to $(0,0)$ and $\theta$ is simply the angle between $(a,b)$ and $(0,0)$ and the real axis.
And we can always find this $\theta$ by solving $\tan \theta = \frac ba$ and determining the proper quadrant by the positive and negative values of $a,b$.
So if $w = \sqrt 3 - i$ then if $r = \sqrt {\sqrt 3^2 + 1} = 2$ we have
$w = 2(\frac {\sqrt 3}2 - \frac 12 i)$.
And we can solve $\cos \theta = \frac{\sqrt{3}}2$ and $\sin \theta = -\frac 12$ and $\tan \theta = \frac 1 {\sqrt{3}}$.  That theta is $-\frac {\pi}6$.
So
$w = \sqrt 3 - i$
$=2(\frac {\sqrt 3}2 - \frac 12 i)$
$= 2(\cos (-\frac \pi 6) + \sin (-\frac \pi 6) i)$.
And .... that's that.
====
Oh!  Important post-script!
If you have $w = a + bi$ and you want to find the right $\theta$ and you think,  "Okay, I've got to figure out $\sqrt {a^2 + b^2}$ and I have to divide $a$ and $b$ by it..."
You don't.  Note:  $\tan \theta = \frac {\frac a{\sqrt{a^2+b^2}}}{\frac b{\sqrt{a^2 + b^2}}} = \frac ab$.  So $\theta = \arctan \frac ab$ or $\theta = \arctan \frac ab +\pi$.
So given $w = \sqrt 3 - i$ we need to simply solve $\tan \theta =  \frac {-1}{\sqrt 3}$ with $\theta$ in the fourth quadrant.
As to WHY that works is because $w = 2(\frac {\sqrt 3}2 - \frac 12 i)$ but we don't have to do the (somewhat) tedious calculation $a' = \frac {\sqrt 3}{\sqrt{(\sqrt 3)^2 + (-1)^2}}$ and $ b' = \frac {-1} {\sqrt{(\sqrt 3)^2 + (-1)^2}}$


How to derive the hydrostatic equilibrium equation from the variational principle?

Question: I was reading the book "Advanced Stellar Astrophysics" (William K. Rose, 1998) and I came across a different approach to deriving the hydrostatic equilibrium equation. First he defined the total energy of a static, spherical star,
$$
E = \int udM - \int \dfrac{GM}{r}dM, \tag{1}\label{1}
$$
where $ u $ is the internal energy per gram. Then he defined the Lagrangian change in the internal energy density,
$$
\Delta u = u(r + \xi(r)) - u_0(r),
$$
where $ \xi(r)$ is the Lagrangian displacement and $u_0(r)$ are the undisturbed values of the internal energy density.  The next step is completely strange and doesn't make much sense to me: He makes a Lagrangian variation in \eqref{1} and looks like:
$$
\Delta E = \int \Delta u dM + \int \dfrac{GM}{r^2}\xi(r)dM \tag{2}\label{2}
$$
which he calls,
$$
\Delta u = - P\nabla\bigg(\dfrac{1}{\rho}\bigg) = \dfrac{P}{\rho^2}\Delta \rho
$$
How did he arrive at these last two results? I can't deduce that $r^2$ in the denominator of the second term of the equation \eqref{2} and neither the positive sign.
Comment: Hint: Substitute $r \to r + \xi(r)$ and subtract from original equation. Remember $\xi(r) \to 0$
Comment: Thank you! got here doing this and then expanding
Answer: So I am missing why this proves what it is intended to prove, but I can certainly fill in your missing details.
So the claim is that we examine a perturbation$\delta r$ which is very very small and for any other quantity we define $\delta F = F(r + \delta r)-F(r)$ to first order.
We insert it in every single term in the integral (this is the part which I find suspicious) and have
$$\delta E =\int\mathrm dM\left(\delta u - \frac{GM}{r+\delta r} + \frac{GM}{r}
\right).$$
To answer your first question, the middle term satisfies
$$\begin{align}
- \frac{GM}{r+\delta r} &= -\frac{GM}r \frac1{1+\frac{\delta r}r}\\
&= -\frac{GM}r \left(
1 - \frac{\delta r}r + \left(\frac{\delta r}r\right)^2 -\dots
\right)
\end{align}$$
by the usual rules of geometric series. To first order we keep the first two terms only.
Second there is the claim that $$\delta u = - p~\delta V,$$a standard claim of thermodynamics which again just sort of doesn't make sense here but that's because I don't see exactly what the argument is. Since $u$ is the internal energy per unit of mass then $V$ should be the volume per unit of mass, which makes it exactly $V = 1/\rho$ where $\rho$ is the mass density. Doing a Taylor series $$\delta\frac1\rho =-\frac{\rho'~\delta\rho}{\rho^2}$$ to first order.
I think I can make sense of this but I do not think I can make sense of this inside of that integral sign which I would want to rewrite as $$\int \mathrm dM =\int  \rho(r)\mathrm dr$$ and then I would never do a Lagrangian path variation on $r$ but on $\rho$ maybe. I spent a little time trying to Google ways to do thermodynamics as a sort of calculus of variations problem, and got a lot of black hole thermodynamics papers which figures. I suppose one could try to maximize the entropy or so, maybe minimize a free energy assuming that the core of the star is held at a very constant temperature or so, argue that the density profile which minimizes this should be the quasi-static equilibrium? But again, varying $r$ just sounds like you are doing a fancy version of the normal, "balance two forces against each other" argument and this integral over $\mathrm dM$ is spurious?
Comment: That was exactly what didn't seem to me to make any sense. I followed a path similar to that suggested by the book to prove that the star's hydrostatic equilibrium state corresponds to a stationary point in relation to the total energy. To do this, I tested the idea of disturbing the star in an adiabatic, but arbitrary and infintesimal way. After some manipulations and boundary conditions, come the expression of the variation of the gravitational potential energy, which you kindly derived.
Comment: And it worked! In the end it appeared that in order for the condition for hydrostatic equilibrium to be recovered we must have to, $$\dfrac{dP}{dM(r)} = - \dfrac{GM(r)}{4\pi r^4}.$$ which is precisely the Lagrangian version of hydrostatic equilibrium!


How to use Ionic Framework for Web App Development?

Question: Is it possible to use ionic frameowork for regular Web Applications rather than wrapping it in Cordova?
Comment: It looks like the newer versions of Ionic are aiming to work with true web browsers in addition to webview containers. "Ionic 2 is focused on building both native/hybrid apps though Cordova, as well as adding the ability for **Progressive Web Apps** and Electron ." [source](http://ionicframework.com/docs/overview/#browser-support)
Comment: I'm curious too. I agree that this should be possible (about to go try), but wondering why there are no Ionic mobile websites.  Perhaps because it only supports webkit and devs are worried it won't work with Firefox for Android?
Comment: Their direction of Ionic is only made for Hybrid Web Apps that are going into the App store.  There are issues that will not be resolved for a pure web solution.
Comment: @xivo Do you already know such issues? We had an idea that ionic`s components will look same in mobile browser (comparing to "wrapped" mode).
Comment: @the_ghost we had our issues with them because translate was not supported or worked improperly for many cases in mobile browsers and Ionic uses that quite often and caused issues.  I don't know if this the case anymore.
Comment: One problem I have found is mouse wheel support in Firefox. It works fine other browsers. But it lets you drag the screen like a touch+drag.
Comment: It's a bit closer to reality. [Serve Rails API and Ionic mobile website together](http://stackoverflow.com/questions/36074227/serve-rails-api-and-ionic-mobile-website-together)
Answer: This is possible if you include the components of www/lib/ - This folder contains the core of ionic(the ionic framework + angularjs) and you can proceed from there.
However it's important to note that ionic was built on top of angularjs, specifically with mobile in mind. To get better results for web app development, you should consider using core angularjs(for functionality) and bootstrap3 (for UI).
Comment: Though there is no official support, Anguar is used for logic while bootstrap is used for design. I have used both in several projects. There is no need to serve bootstrap js through angulars dependency injection. Keep bootstrap files in a separate "media" folder and load them once in a base.html template (which extends all templates) and there will be absolutely no issues.
Comment: For AngularJS and bootstrap simply use the bootstrap.css and then angular UI - it works seamlessly - For clarity sake DO NOT use bootstrap.js with angular
Comment: Unfortunately support for Bootstrap 3 and AngularJS 1.3 is not optimal currently (Dec-2014). There are at least 2 projects wrapping Bootstrap for AngularJS: [Bootstrap UI](http://angular-ui.github.io/bootstrap/) has no official support for AngularJS 1.3 and [AngularStrap](http://mgcrea.github.io/angular-strap/) seams to have less "official" support from Angular team. I wouldn't know which of both I should choose. Of course most of Bootstrap can be used without JavaScript so it's a big gain to use this awesome CSS framework.
Comment: I use angular-bootstrap which is quite compatible and performs well. http://angular-ui.github.io/bootstrap/
Comment: is is possible to keep the business login in common (like in common Angular services) and user Ionic on mobile but Bootstrap for web?
Answer: V2
Ionic now supports PWA(web apps) and support for desktop is coming too soon
Ionic build browser
V1
Ionic can be used for regular web development. If all you need is web dev stop here. But if you want your app & web to serve from the same codebase read further
Step 1
Create a copy of index.html inside merges/browser/ (merges is at the root level i.e myApp)
 include

&

Step 2
Remove unnecessary js files like cordova.js from index.html
Step 3
add in app.js
var is_app = (typeof is_browser === 'undefined' && !ionic.Platform.is('browser')
              && ionic.Platform.isWebView());

Now use css hide/show or angular hide/show using these
Answer: While I don't believe there is much support for anything but hybrid web apps in Ionic, you can check out Mobile Angular UI for a very similar alternative with support for the mobile web.
Answer: Orane is right.
When You "node app.js" your app runs a server. We need to provide this server with all files we want. With Ionic Application it's basically www folder. In following example i put all contents of www folder to my public folder.
My root folder has app.js file and public folder. That's how app.js looks like:
var express = require('express');
var app = express();
var server = require('http').createServer(app);

app.get('/', function (request, response) {
    response.sendFile(__dirname + "/public/index.html");
});
app.use(express.static(__dirname, 'public'));

In public folder i have all frontend css and js. We included the whole folder public in code above. Now in index.html of public You should include files with public/, like this:

All the best, anybody, feel free to ask anything about Node.js+Ionic Framework
Answer: Depending on the complexity of the app it is absolutely possible to use the Ionic Framework for regular web applications!
When you create your app there is a /www folder that contains all your HTML, JS, and CSS. That's the front end for your web app.
Most web apps are simple interfaces that access data with only a little bit of logic in between. In most cases you can put that logic in your JS and let the clients handle the workload.
Data can be handled by a Backend-as-a-Service (BaaS) solution like Firebase or Parse. I like Firebase because it ties in nicely with Angular and Ionic.
If you need to connect to services that require secrecy, like credit card payments, you can hook in to a service like Zapier.
For hosting there are a number of static app hosters that have popped up specifically for serverless apps. I prefer divshot even though they don't seem to be actively pushing out new features anymore.
The solutions I've outlined here will help you maintain the consistency across platforms that makes Ionic great!


What is planetary surface temperature given constant sub-surface temperature?

Question: If a planet of radius $R_1$ has a constant sub-surface temperature $T_0$ at $R_0<R_1$, what is the long-term equilibrium surface temperature $T_1$?  Say we assume constant thermal diffusivity of the planet material, surface emissivity $1.0$, no atmosphere, and no incoming radiation.  I figure the temperature profile is harmonic, i.e. $T=a+b/R$, for constants $a$ and $b$, and that we can use $(R_0,T_0)$ to eliminate one of these constants.  Is there enough information to obtain the other constant?
Answer: You want to equate the conductive energy flux at the surface which is a constant times T1-T0 -given your geometry and conductivity you can determine the coupling factor, with the radiative heat flux sigma*T**4. You could also add in the CMB, which is simply the same sigma*T**4 using the CMB temperature. Then you simply have a nonlinear algebraic equation in T0 to solve. It should be solvable by iteration without much effort.
Comment: So I need to find a coupling factor k, depending on R0, R1 and the conductivity, then solve k*(T1-T0)=sigma*T1**4 for T1?  That's great!  Do you have any pointers about figuring out k?  A reference?
Comment: Fourier's equation gives $Q= -k Area dT/dR = -k 4 pi R^2 dT/dR$, So integrating gives $Q \int_{R0}^{R1} 1/R^2 dR = -4 pi k (T1-T0)$ or $Q = -4 pi k (T1-T0) R0 R1 / (R1 - R0).$ Setting equal to radiated flux from the surface gives: $-4 pi k (T1-T0) R0 R1 / (R1 - R0) = sigma T1^4 4 pi R1^2.$ So we need to solve that for for $T1.$ Does that seem about right?
Answer: That is easy: an object at temperature T0 in a zero temperature environment (no incoming radiation) will radiate till its temperature is zero. So the long term equilibrium is zero.
The question as posed describes a hypothetical situation, there is no environment at zero temperature. The universe is filled with CMB radiation of finite temperature that drops in time due to the cosmic (accelerated) expansion. So the real situation is a wee bit more complicated...
Comment: The problem assumes that the temperature at R0 is constant across time, i.e.  T(R0,t)=T0 for all t>0.  The question is what is T(R1,infinity) ?   Assume CMB is ignored.
Comment: The question says "If a planet of radius R1 has a constant sub-surface temperature T0 at R0 < R1, what is the long-term equilibrium surface temperature T1?" If T0 is not the starting condition, but T(R,t) = T0 for all R0, then that same value is the (trivial) answer: T(R1,t) = T0 for all t>0.
Answer: Sorry for the confusion.  R0 is some given particular radius between 0 and R1, e.g. R0=5000, R1=6000 km.  R is the general radial variable, as in T=a+b/R.  T0 is the temperature at position R0, assumed constant throughout time.
Comment: How can the temperature at R=R0 stay constant if at the same time you assume the body at R=R1 to radiate into a zero temperature environment? Where is the energy coming from?
Comment: Let's say an internal energy source.
Comment: Ok, in that case the temperature at surface is zero, so: a = -RO T0/(R1-R0) and b = R0 R1 T0/(R1-R0).
Answer: Assuming your planet is uniform and at equilibrium your planet will be losing heat due to radiation at a rate of
$$\dot Q=\sigma\,A\,T^4=4\,\sigma\,\pi\,R_1^2\,T_1^4$$
This $\dot Q$ must be coming from the interior to maintain equilibrium and pass through all of the crust. Thus
$$\frac{dT}{dR}=-\frac{\dot Q}{k\,A}=-\frac{\dot Q}{4 k\,\pi R^2}$$
$$\int1 \;dT=\int-\frac{\dot Q}{4 k\,\pi R^2}\;dR$$
$$T=\frac{\dot Q}{8 k\,\pi R}+C$$
Then you can plug in for $\dot Q$ to get:
$$T=\frac{\sigma\,R_1^2\,T_1^4}{2 k\,R}+C$$
Then you can use $(R_0,T_0)$ to find $C$
$$T=\frac{\sigma\,R_1^2\,T_1^4}{2 k}(\frac1{R}-\frac1{R_0})+T_0$$
Now you can find $T_1$
$$T_1=\frac{\sigma\,R_1^2\,T_1^4}{2 k}(\frac1{R_1}-\frac1{R_0})+T_0$$
$$\frac{\sigma\,R_1^2}{2 k}(\frac1{R_1}-\frac1{R_0})\,T_1^4 -T_1+T_0=0$$
While there are exact analytic solutions to this forth order polynomial they are longer than would be prudent to post here, and evaluating them would most likely result in more numerical inaccuracy than a simple numerical method on this equation.
A simple recursive method that should converge quickly would be:
$$T_1^\prime=\sqrt[4]{\frac{2k(T_1-T_0)}{\sigma\,R_1^2(\frac1{R_1}-\frac1{R_0})}} $$
For values of:
$$R_1=4000mi$$
$$R_0=3999mi$$
$$T_0=300K$$
$$\sigma=5.67\times10^{-8}\frac{W}{m^2\,K^4}$$
$$k=5\frac{W}{m\,K}$$
And an initial guess of $T_1=200K$ yeilds $T_1=70.8K$ after 3 iterations (70.79020354 after 10)
Answer: I wouldn't think the planet's radius would have any effect on its temperature, especially if the temperature, as you say, is fixed for given planet.


Check current TTL on collection columns in Cassandra

Question: Lets assume I have a Column Family with following schema:

CREATE TABLE users (
    user_id timeuuid,
    name varchar,
    last_name varchar,
    children list,
    phone_numbers map,
    PRIMARY KEY(user_id)
);

Then I insert a row into this CF with "USING TTL 60000". When I want to verify if any of these columns still has TTL set I get error: "Cannot use selection function ttl on collections".
My question is: how to get TTL on elements of a column that is defined as collection ?
Cheers!
Answer: I reproduced your problem -- naturally getting the very same result. The problem is that either (1) in collections TTL's are element-wise (one TTL per entry in collection) and (2) I found no way of getting entries from Maps or Lists.
Of course I can delete one element -- but selecting it or it's TTL was not possible. Even the Datastax' CQL driver v2 has not provided the metadata for that.
So you may change your data structure for that. If this was 'just' for testing purposes you have to trust Cassandra doing this well enough.


Can I use any character for the name of my app?

Question: I'm preparing to publish an app I developed but the name I had in mind is already being used. To solve this I'd like to add a character/symbol (which relates to the name and gameplay) besides the name: ⟡. Is there a problem with doing this? Would this affect my app's visibility on the App Store.
Comment: App names are needed for search. If you use a character then that wouldn't be indexed.  People would find it very difficult to search for your app (assuming Apple allows the character to be used).  Did you look at the App Store guidelines for rules about app naming?
Comment: @fsb If the app name is just two words and the symbol, wouldn't people find it if they just type the words? Would the app be easier to find if there's no symbol at the end?
Comment: I take back what I just said :-).  While I hadn't previously seen special characters in a name, I searched the App Store using *, -, and ( and I saw many apps with those in the name. So it's allowed and devs are doing it. I would never think of searching for a special character in the name unless I knew the app name specifically, so it's something to think about.
Answer: According to the App Store Review Guidelines, names can be anything so long as they are no more than 30 characters, do not infringe on copyright, and are unique.
So, yes, you can use the ⟡ Unicode character in your app name so long as it follows the guidelines above and on the website.
Comment: But would it make it difficult to find on the App Store?
Comment: @gabe - There's really no way to be sure as that is up to the algorithm in charge of searches on the app store. You are able to change the name of your app, so there's always the option of putting ⟡ in the name, seeing if it works for you, then changing it to the name without the star if it doesn't. Searches are also based on keywords you provide, so the better keywords you provide, the easier it will be to find.


How to share android directories over LAN using SMB protocol

Question: I want my hone to be used as network drive, by sharing folders over network. So that I can access it from My windows PC. I want to use SMA protocol for that.
I am using OnePlus One, CM12.1 OS with ES file explorer.
Answer: If you have a rooted phone, you can use one of these two apps that let you set up a samba server: Samba Server or SambaDroid (they are portings of Samba for Linux). Of course, you can find and use any other equivalent app. Root is required because Windows doesn't recognise non-conventional servers (i.e. which use non-standard ports), so you must be able to change the default ports on your phone.
If your device is not rooted, then you can:

create a Samba server with your PC, granting read/write privileges to the shared folders
use Es file explorer as a samba client (the smb protocol is built in)

In order to do it, follow these steps in Es (I will cover only the android side, assuming you know/will find out how to set up servers on PC):

open side menu, go to 'network' and choose LAN
touch the plus sign at the bottom right corner, this interface will pop up:

leave the 'domain' field empty
fill in the server name (local ip address of your PC), and username and password that you set up for your server
do not check the 'anonymous' box (if your server isn't password protected then check it)
choose a name for the server to be displayed on your phone
And that's it.
This should do the trick (as long as you enable r/w on your PC), doesn't require root and is well built in to Es file manager.


iPhone 5 upgrading after syncing with iTunes

Question: I synced with iPhone and was asked whether I wanted to upgrade my iPhone 5.  After that I could not open my phone.  When pressing the started button I get a picture of what looks like a charger with an arrow pointing to iTunes.  I tried to reboot, but to no avail.
Comment: Do what it says, connect it to iTunes.
Answer: When you see the lightning cable and iTunes logo on your screen, it means that your iPhone has entered Recovery mode.
The best thing to do is to connect your iPhone to iTunes on a Mac or Windows PC and restore it.
ITunes should display a popup saying that you connected an iPhone in Recovery Mode.
From the screen in iTunes, select restore or restore and update. (Actual button names could be different as what I say)
After you restored your iPhone you need to configure it. If you want, you can restore a backup from iCloud or iTunes when there's one available.


Does my ceiling fan's down rod need extra support?

Question: I am planning on installing a ceiling fan with a light kit (about 17-18lbs total), with a 24" down rod and was wondering if the down rod needed to be supported.
It is a new installation and will be installing the proper box, but was concerned about the down rod only...seismic support(?)
Thanks.
Comment: When you ask if the down rod needs to be supported are you meaning laterally supported to stop wobbling? Whatever you mean the 24" rod would not need extra support. It will fit in the end at the ceiling with the shroud and on the fan exactly as the shorter pipes which come with the fan.
Comment: If you live in a seismically active zone, you may be required to have a special cable as a back up to the standard suspension. Some ultra high performance fans come with a safety cable which must be secured to a ceiling joist. In an earthquake the standard support bracket may not be considered sufficient to secure the fan. Check with your local fan store or building inspection.
Comment: How high is the ceiling where you plan to install the fan? What is the make and model of the fan you are planning to install?
Comment: Was there a fan in this location before and you are replacing it with a new fan? Or was there only a light fixture at this ceiling box and now you want a fan with light kit under it?
Answer: Look in the parts for your fan and see what is the longest pipe that comes with the fan. You will probably find two pipes, but even the longer would be much shorter than 24".
Go online or to a "fan store" and get a 24" pipe specifically made for your fan. It will be installed in place of the shorter pipe that comes with the fan and will come painted to match your fan.
How tall is your ceiling? Be prepared to give that measurement to at the fan store and they might advise you to get a different length pipe--either shorter or longer than 24". As a rough guide I would say that a 24" support rod would be about right for a 10' ceiling, depending on how far down your light kit projects and what you preference is.
The wires that come on the fan are much longer than needed for short pipes and are probably long enough for a 24" pipe without having to add extra wire, but you will have to see what the instructions say.
EDIT
The modern cheaper fans (e.g., Hunter) can be installed at the location of a box which formerly held only a light fixture if there is a ceiling joist next to the ceiling box. The fan installation kit has a bracket with long screws which go into the ceiling joist which a box is nailed to.
But if the joist is not adjacent to the ceiling box, then the box may well be a light duty one which is on a light metal bar which would not support any fan. In that case the existing box and bar would have to be removed through the existing hole and a fan box with bar installed (through the existing hole).
EDIT2
For example see Down rods for Hunter fans
EDIT3
Note that if you need to substitute a fan support bar for the existing one, you need one which is designed for retrofit through the existing hole. There are some fan support bars which will only work if there is no drywall in place. These are much cheaper but they cannot be inserted through an existing 3.5" or 4" hole in ceiling drywall whereas the retrofit ones can be.
EDIT4
In case of failure of the primary fan suspension safety cables will provide a backup. Safety cables may be required in seismic zones, and in certain applications such as schools, daycare facilities, nursing homes, etc.
Panasonic info on safety in fan installations
None of the fans I have ever installed, or had installed for me, has a safety cable.
Comment: Save all the parts they need to be changed over to longer rod.And take notes how they came off.
Comment: Untrue.  All ceiling fans need fan rated boxes.  *Especially* the cheaper ones because they will be poorly balanced and have high dynamic forces. A plain box installed at a joist is not a ceiling fan rated box.
Comment: I installed three of the new Hunter Fans. These have hardware which does not use the ceiling box for support and are designed to retrofit to replace a light without changing the box, if there is a ceiling joist adjacent to the box. The suspending bracket for the fan is secured by long, heavy screws which go vertically into the edge of the ceiling joist. The fan is centered on the joist (not on the box) but the shroud is so large that it covers the box. This cannot be used where the location of the fan is between joists. I have other fans which required the fan rated box/bar.
Answer: IF you already had a previous fan there then you should not need any support as the Outlet Box should of been installed there to support a fan, if this is a new installation or you are just replacing a fan you will need a ceiling fan Outlet Box, just search google. As for the short or long rod it doesnt matter as the weight is the same but you will need to make sure you have a ceiling fan Outlet Box. Usually you can identify those boxes because the have a little hook where you can hang the fan when installing it.
paul
Comment: Most of the modern basic fans  do not attach via a hook inside the ceiling box.  Decades ago I hung some heavy Hunter fans which were supported by a heavy hook which screwed into the ceiling joist or into a 2x4 between the joists. In the last few years I installed some lighter duty Hunter fans which did not require this heavy hook.
Comment: Point being you need an outlet box that support the weight of a fan.
Comment: Thank you for your input, Paul and Jim! Your time and knowledge is much appreciated.  I've gain a lot by the answers!
Comment: 40 years ago I installed three of the heavy, oil bath Hunters in our house. These are supported by a single heavy hook which screws into a ceiling joist or a 2x4 cross member.  More recently I installed several of the lighter, ball bearing Hunters in a relative's house and followed the instructions to the letter. The support bracket for latter can secured to the ceiling joists with a pair of long screws provided. More recently still we had two of the new Hunters installed in our house in rooms which had no ceiling fixtures. The electrician used the bar/box rated for fans to bridge joists..


Why does Warren Buffett say his fund performance, relatively, is likely to be better in a bear market than in a bull market?

Question: Currently, I am reading his annual letter. In his letter, he always says that his fund performance is likely to be better in a bear market than in a bull market, but I don't know why. Could someone explain this to me?
http://www.safalniveshak.com/wp-content/uploads/2013/12/Warren-Buffett-Berkshire-Letters-1957-2012.pdf
Comment: "*Relatively* better in a bear market than in a bull market" is simply another way of saying "less volatile than the market as a whole".
Comment: Probably because he tends to shy away from the big multiple companies that tend to be popular/overbought in bull markets.
Answer: Buffett is a value investor. His goal is to buy good companies when the market is overly worried and prices them below intrinsic value. When the market is highly priced it is much more difficult for him to find things that he thinks are at an attractive price. When people are very worried and the market has crashed, stocks are then priced below their intrinsic value and he can use the cash he keeps in the company to make attractive purchases.
Remember that Buffett is not concerned with the ups and downs of the price of Berkshire Hathaway stock, he is concerned with the economic value of the assets that the company owns. So if all stock prices crash and he can buy things that are at bargain prices, he is happy no matter what Berkshire stock price does in the short run.
One consequence of value investing is that because you are buying assets at bargain prices, the total value of your assets drops less in a bear market than the highly priced stuff that drives the major indexes.
Answer: From the letter you link:

Our performance, relatively, is likely to be better in a bear market than in a bull market so that
  deductions made from the above results should be tempered by the fact that it was the type of year when we
  should have done relatively well. In a year when the general market had a substantial advance I would be well
  satisfied to match the advance of the Averages.

Putting those two sentences together, the word relatively means that his funds perform better than the market in bear markets and perform about the same as the overall market in bull markets. It does not mean that absolute performance is better in bear markets than bull markets.
Later on he states

This policy should lead to superior results in bear markets and average performance in bull markets.
Answer: Warren Buffet and Berkshire Hathaway took a 50% loss in each of the last two bear markets. His stock even lost 10% in 2015 when the S&P lost 8%.
He doesn't have a track record to support the claim that his stock performs relatively better in a bear market, so perhaps it's best to take his letter with a grain of salt.
Edit: As one commenter points out, Mr. Buffett is comparing the book performance of his fund to the market performance of an index. That is an apples to oranges comparison. It's deceptive at best.
Answer: If I have $100 and put it under the bed it will return 0%.  Relatively good in a bear market and relatively bad in a bull market.
Answer: To understand his comments about bear-market performance it's important to take them in context. (My research method was Crtl+F: bear; read around the highlights. This is not a complete survey of 60+ years of letters.)
In his earlier letters, statements about bull market performance are always made in reference to Buffet's belief that many of BH's current holdings are in undervalued securities. Ex:

To the extent possible, therefore, I am attempting to create my own work-outs by acquiring large positions in several undervalued securities. Such a policy should lead to the fulfillment of my earlier forecast – an above average performance in a bear market. It is on this basis that I hope to be judged (p 6; emphasis mine).

Similar statements are made throughout the earlier letters, along with this interesting note:

In a year when the general market had a substantial advance I would be well
  satisfied to match the advance of the Averages (p 6).

So to your question of why BH fund performance is likely to be better in a bear market than in a bull market, I believe the implicit assertion is that undervalued securities are more resilient in a bear market (presumably because they don't have as far to fall, and are also less likely to be subject to a bubble). Buffet is also explicitly asserting that when facing a choice to either (a) position BH to weather a possible downturn or (b) position BH to enjoy a bullish stock that is outpacing the market, he would choose the former over the later.
As to your assertion that he always says this, I can find no reference to bear market's in the letters past 1960.
Comment: Warren is focused on book value, that's one key measure he uses for his results, not stock price. In the long run they will correlate, but not always in the short turn. Essentially he has better opportunities to buy undervalued investments in a bear market, which is incremental to Berkshire's book value. That value won't always be reflected in the stock price in a bear market, but over time it will be.
Comment: "Essentially he has better opportunities to buy undervalued investments in a bear market" @RandyHill That's true, but it's not what Buffet was saying in the passages OP is asking about. Specifically, Buffet is referring to the performance of securities already held under hypothetical future market conditions (bull vs bear), not the acquisition of new securities. IE: He's saying *if things go bad BH will be okay,* not *damn, it would be great for BH if things went bad,* the latter being very poor PR.
Comment: Michael, again I think you are mis-reading his intent. He doesn't care about short term price performance. He cares about the accretion of value from buying at a bigger discount to intrinsic (actual) value. Imagine a stock trading at $100 that he thinks is fairly valued. In a bear market it drops to $50, so every $50 he invests in it is worth $100 in intrinsic value. If he can buy $2B of stock at 50% of intrinsic value he's increased BRK's value by another $2B, regardless of where the purchased stock or BRK trade over the next months. Bear markets are where he creates the most value for BRK.
Comment: @randy I think you're projecting your own meaning onto his intent. did you read the letters? Everything you're saying about market theory is true, but I do not think that's what he's communicating in the statements OP asked about. Again: in the letters he is talking about performance of existing securities under future market conditions, not acquiring new securities should market trends turn. Saying that he likes to buy stocks at a discount during a bear market is true but also off-topic
Comment: I've read every letter, from Buffett Partnership through Berkshire annual reports, etc. When he uses the term "workouts" he's talking about buying special situations (mergers, spinoffs, liquidations, etc) that are easier to find in bear markets, and typically short-term investments that are offer less variance and higher returns than general stock picking (what he referred to as general issues). He stopped doing workouts in the 70s, his portfolio simply got too large for most of them to have an impact, which is a shame.


Can I transfer a USA transit visa to a visit visa online without going to the consulate of USA?

Question: Can I transfer a USA transit visa to a visit visa online without going to the embassy in the USA?
Comment: @traveller There's a C visa. See https://travel.state.gov/content/travel/en/us-visas/other-visa-categories/transit.html
Comment: AFAIK the US doesn't issue transit visas as such. What exactly are you trying to do?
Comment: What kind of visa do you actually have? If you have a B1/B2 visa that was issued for the purpose of transit, which you already used, and is still valid (in duration and number of entries), yes, you can use it for any other purpose that is within the allowed activities of a B1/B2 visa. If you have a C visa (which is quite rare), then you would need to apply for a B1/B2 visa. But depending on your place of residence, there are quite a few chances you could not get to the US in any case in the current circumstances.
Comment: @jcaron there were 848 C-1 visas issued in January 2020, which is a bit more than 0.1%, but that doesn't include the combination C-1/D visas, of which there were considerably more (these are issued to crew members).
Answer: No, you cannot.  You must apply for a new visa and pay the visa application fee.
Answer: No. There is no such thing as "transferring" a visa from one type to the other. You will have to make a new appointment, fill out the DS-160 again, pay the fee again, and go through basically the same process to get a B-1/B-2 visa. Although not required, they will probably mark your C-1 visa "cancelled without prejudice" to avoid confusion at the border. You can transit on a B-1/B-2 visa, so there's never a need to use the old C-1.
Just to be clear, if you told the consulate you wanted a visa for transit purposes, but you actually have a B-1/B-2 visa in your passport, you already have the correct visa type. There is no need to do anything.


Does Qiskit allow for QASM 3.0 code to be utilized?

Question: I am interested in using QASM 3.0 after reading it's documentation and seeing it's examples 1. However, I see that in IBM Quantum Experience QASM 3.0 is not supported yet. Is there any way I can run QASM 3.0 code locally or by a customized Qiskit install? Also is QASM 3.0 still in active development and is there a timeline? Long story short I feel like there is documentation I am just missing/not finding.
Answer: OpenQASM 3 is under active developement (as in July 2022), with several working groups that are adding new features regularly.
I am not aware of a timeframe, but you can ask in the #open-qasm channel in the Qiskit Slack and watch the recordings on the OpenQASM 3 TSC Meeting (links in the same slack channel).
At the moment (July 2022), Qiskit support for OpenQASM3 is limited. It does not have an importer (OpenQASM3 -> Qiskit) but it has some sopport for exporting (Qiskit -> OpenQASM3). For example:
from qiskit import qasm3, QuantumCircuit

qc = QuantumCircuit(2,1)
qc.h(0)
qc.cx(0, 1)
qc.measure(0,0)
qc.x(1).c_if(0, 0)

print(qasm3.dumps(qc))

OPENQASM 3;
include "stdgates.inc";
bit[1] c;
qubit[2] _all_qubits;
let q = _all_qubits[0:1];
h q[0];
cx q[0], q[1];
c[0] = measure q[0];
if (c[0] == 0) {
  x q[1];
}

Comment: Thank you for the update. I had already noticed the ability to go Qiskit->QASM, and I appreciate the clarification.


Cursor disappearing in a Ideapad Yoga?

Question: Upgraded from 13.04 to 13.10 on my Ideapad Yoga yesterday, hoping it might have fixes for a couple of issues I've been having. While it seems to have made the touchscreen more usable, it has made the problem with my trackpad even worse.
In 13.04 and below, the cursor occasionally (maybe once or twice a day) would completely stop working and to get it working again I would run
sudo modprobe -r psmouse
sudo modprobe psmouse

and it would be happy again, now every hour or so, my cursor just goes invisible, you can tell its still there as you can hover over things and they will respond. Again running
sudo modprobe -r psmouse
sudo modprobe psmouse

works but it's getting a little annoying now its so frequent!
Does anyone have any suggestions on things to try?
Comment: Maybe [this could help][1]. Worked for me.

  [1]: http://askubuntu.com/questions/360423/mouse-cursor-flickering-and-disappearing/360473#360473
Comment: Thanks, but I saw that before I posted this and it shows up as just 1 "built-in display" :(
Comment: possible duplicate of [Mouse cursor disappearing at every second boot Ubuntu 13.10](http://askubuntu.com/questions/367459/mouse-cursor-disappearing-at-every-second-boot-ubuntu-13-10)
Answer: FYI, doug's response here seems to have solved the problem for me. Several hours now with no issue. Using Synergy heavily as well, which was always a sure way to make it vanish.
The gist: gsettings set org.gnome.settings-daemon.plugins.cursor active false
Thanks for the modprobe suggestion, though. That made the issue at least tolerable!
Comment: Thanks, not looked at the other question since - tried that now so will see how it goes :)
Comment: Worked for a while but it happened again (so much less regularly!) now I could just do with finding out how to do something like the modprobe trick to get it working again :)
Answer: Try hitting alt + ctrl + F6, then alt + ctrl + F7.
This will switch two virtual console 6 then back virtual console 7. This brings my mouse pointer back. If it works for you then you can do this automatically by adding a script to:
/etc/pm/sleep.d/
I called mine 'mouse_hack' and in it all I have is: 'chvt 6; chvt 7'.
It should be owned by root, and be executable.
This just automates what you did manually above whenever your computer resumes.
Answer: This is not a complete answer but may mitigate the problem. This occurs for me when I unlock my computer, among other conditions (VLC, as mentioned, forr example). If you put your modprobe lines into a bash script and place the script in /etc/pm/sleep.d , then it runs automatically on resume, and this for me makes sure I have my pointer each time I wake up my computer.
Bit of a hack for now, but it saves me some trouble at least.

Cursor disappearing in a Ideapad Yoga?


Restore gmail messages to mail.app after TimeMachine restore

Question: I have a dozen different email accounts for different roles, all of which I interact with through mail.app.  I had a hard drive disaster, and restored from TimeMachine.  It did an impressive job of restoring my complex email structure for backed up email, and of course new emails coming in are fine.  But I am missing the month (urgh) of emails between the most recent backup and the restore.  They are still on gmail (some POP and some IMAP accounts).  How do I mark them as not already downloaded, so that they'll be retrieved from gmail?
Answer: For the mailbox in question, in the Mail.app, go to Mailbox (top menu), and then select Rebuild. You may need to relaunch the app for the older messages to be downloaded.


Problem binding hover event to combobox items

Question: I've got the following situation. I need to show a tooltip with custom text when the mouse cursor is over the combobox items (over the "option" tag). My first idea to resolve this was using the title tag. It has worked well with Firefox, but with IE, when the text is too large, it got truncated.
Then, I thought about using a div as a tooltip, and show/hide it. I've created the following code, and it works on Firefox (the enter and leave events are triggered), but again in IE they don't do nothing.
<code>    $(document).ready(function () {
        var $tooltip = $("#tooltip").hide();
        var $options = $("#ddlSelect option");
        $options.each(function () {
            var texto = $(this).attr("title");
            $(this).data("title", texto);
            $(this).attr("title", "");
        });
        $options.hover(function () {
            var texto = $(this).data("title");
            if (texto != "")
                $tooltip.show().text(texto);
        }, function () {
            $tooltip.hide();
        });
    });
</code>
Obs. "tooltip" is a div. "ddlSelect" is a combobox with some options. All its "option" have a title tag associated, just to be the initial container of the custom text.
I'm using IE 8. Does anyone knows why IE can't triggers these events?
Thanks
Comment: This may help in understanding why IE doesn't work.
http://stackoverflow.com/questions/2064011/select-option-hover-is-not-working-in-ie
Comment: So there's no way to make it work? Well, I guess I have to look for another solution, maybe using a combo "made of" div's... Thanks!
Answer: I might suggest this example from jQuery UI:
http://jqueryui.com/demos/autocomplete/#combobox
You'll then have to dip in to the plugin code to add a mouseover event setter for your options.


Is publishing a chapter in a book considered as valuable as a journal publication?

Question: I received an invitation from a Prof. in an highly ranked University to publish a chapter in a book (Computer Science). The book publisher is a well known publisher. As far as I know, the chapter will be peer reviewed. The topic is in my research field and considered state of the art topic. The time schedule is tight (one month). I would like to know if such a publication is considered a valuable publication and has equivalent value to publishing a paper in journal?
Comment: Ask yourself whether you could produce a journal article in a month and you have a good answer.
Comment: Would the book chapter contain any new unpublished results, or would it be restricted to reviewing the current state of the art?
Comment: You've not said where you are based. How are academics rated in your field and country (or country you want to get jobs in future). In my STEM field in UK book chapters aren't considered in REF assessment and can be time consuming for little reward. However, in Arts they are considered for promotion.
Comment: Related: https://academia.stackexchange.com/q/5556/1033
Answer: They are not equivalent, and the relative value depends. That's the distinction between primary and secondary literature. Many classic 'papers' in my field are not papers but book chapters with novel arguments (not data, obviously, those would be in a paper.) Both are valuable and having both in the CV is better than having only one of the two. If I were in the middle of finishing a research paper and a book chapter offer with a tight deadline came along, I would pass. But you don't mention having to choose one over the other, so it's to your advantage to accept.
Comment: In my field (linguistics), journal articles have traditionally been considered far superior to book chapters in terms of their value/prestige, but I notice colleagues of mine starting to push back on the conventional narrative - which I think benefits everyone.
Answer: I would say yes, especially if the chapter provides a mini review with an overview on the topic, plus some new contribution.
And if the professor who is editing the book is well known, it means that they will promote the book, and thus the contribution will have high visibility.
Moreover since their name will be on the book I would expect that the contributions will have higher chances to get cited.
Answer: Evaluating the value of a book chapter (for purposes such as tenure review, salary increases, promotion, hiring, etc.) can be more difficult than evaluating a conference or journal article, as it is not immediately clear how much peer evaluation was done.
On the plus side, you have an invitation by a recognized person in the field. This is like an invited article in a journal, which in Computer Science adds value. On the negative side, without your chapter, the book might be incomplete, so they can at worst prod you to better the chapter if you did a lousy job. (Not that you would ever do that.)
There is also a lot of predatory publishing going on with book-chapter invitations and some few good people have become stooges in a pay-to-publish scam. Since your potential editor has a renown, that is not the case here and an evaluator would hopefully know that. Then of course there are conference articles that are published as chapters in a book such as Springer Lecture Notes. This means that an evaluator has to look closely at the editor and the publisher.
The impact measured in citations is a different category. A chapter in a book might be less visible, as books authored by many people tend to lack coherence (in Computer Science).
So, summing up, a book chapter under these circumstances would not equal a class A publication, but might be better than a class C conference publication depending on the status of the editor. If you can do a good job in a month, I would go for it. You might be gaining the editor as a future letter writer.
Answer: Book chapters comes in different shades.
You have the ones that are 'technically' conference proceedings (CCIS, AICT, LNCS ...).
You also have the reviewed and collated like the one OP described.
Yet, there're the ones that are 'mere' collation.
I'll leave out the technical/subject books.
The weight ascribed/attached to books chapters varies at

country level for funding or research impact
discipline level where order and perception play a part
university level for promotion or funding or ranking.
There are other nuances beyond the three examples.

OP scenario might be considered a valuable publication, given the description.
[Edit]
Prof. in an highly ranked University might also go alongside Prof. is an highly influential, or highly regarded in CS (subfield) conferences, or highly rank in CS (subfield)
Answer: My sinister view is that it benefits the professor more than the authors of each chapter.  The professor will promote his/her name, and harp about having written a 'whole' book by him/herself.


How to get effect like Dodge & Burn tool in photoshop, but nondestructively?

Question: Does anyone know how to get effect like Dodge & Burn tool in photoshop, but nondestructively? Any normal solutions with soft light doesn't change saturation of the color, and I'm looking for effect similar for the Tool. Anyone ideas? :D
Comment: I don't know if it is possible in your situation, but you could perhaps use dodge & burn tools on a raster layer ( or a copy of another raster layer). You could then use Clipping masks or Layer masks on the "dodge & burn layer" if necessary. [Something like this, for instance](https://db.tt/zQMT8q67).
Comment: This is possible and I do this If i need it that way, but for me it doesn't sound very "nondestructively" - If I change colors of below layer I will have to do that again :( But still thank you for answer!
Answer: You'd want to use curves adjustment layers with a mask instead of dodge and burn which allows for changing the amount of "dodge" or "burn" overall and changes to the brush strokes via the mask.
A great tutorial on doing this that goes into great detail & is fairly easy to follow is PHLEARN's video here: https://www.youtube.com/watch?v=kR6yKfoR8eA
Hope this helps!
Comment: First of all thank you for answer. I do know Phlearn resources quite well, what I ask for is not usual Dodge&Burn solutions that are based on Curves/Soft Light layer/Gray Layer - but something that works similar to a Photoshop tool Dodge&Burn. If you give it a try you will notice that a built in tool also increases saturation while burning, that doesn't happen in those previous methods. While usually I don't want to have that, I got a case where this brings much more nice results that I want, yet I don't want to flatter whole image just to use those tools :/


What does the The Episcopal Church mean when it says it allows everyone to participate in Holy Communion?

Question: What does the The Episcopal Church mean when it says it allows everyone to participate in Holy Communion? What is meant by "everyone"? Is it "all Christians", "all observant Christians", or "all human beings regardless of baptism"?
Comment: Can you give a reference for where they say this? It will be easier to answer if the claim is seen in context.
Comment: Yeah. I don't think The Episcopal Church says this at all. More along the lines of "all baptized Christians" I should think.
Answer: Canon 1, section 17 of the Canon law of the Episcopal Church states,

No unbaptized person shall be eligible to receive Holy Communion in this Church.

This restricts reception of Holy Communion to Christians only. Actual practices differ some between Episcopal parishes, with respect to further restrictions on who can receive. I know of parishes where the custom is to allow any baptized Christian to receive, and others which restrict reception to those delay Communion until a later time, for example, until after a course of instruction, which means that some baptized Christians might be excluded, for example those younger than a particular age. Every parishes at which I have attended communion make it public either by posting the information in a prominent place, or by means of an announcement just prior to the Communion part of the Service the particular custom of the parish as far as who can receive communion.
The canons, and the US Book of Common Prayer further restrict who can receive communion. According to the US Book Of Common Prayer, (P. 409) Baptized persons who are living a "notoriously evil life", "those who have done wrong to their neighbors and are a scandal to other members of the congregation", when "there is hatred between members of the congregation", and where there has been hatred, and one side is sincerely repentant, but "those on the other side refuse to forgive"are to be informed privately that they may not "come to the Holy Table until he (or she) has given clear proof of repentance and amendment of life",
In those parishes of which I have personal knowledge, the general custom is that a visitor is welcome to present himself or herself for Holy Communion if that person is eligible to present himself or herself for Holy Communion the parish he or she customarily attends.
Persons who are not eligible to receive Holy Communion, are in some parishes, still welcome to present themselves at the communion rail, in order to receive a Pastoral Blessing.
Comment: well, i'm Mennonite and my wife is Episcopalian and with her, i have attended hundreds (maybe 1000) Episcopal services with the Lord's supper.  never once did i hear any qualification espoused by the celebrant.  i s'pose the celebrant assumed that all who desired Communion were believers and that is all that was implied.  **all** believers were invited to the table.  i never heard any qualification or consolation of a Pastoral Blessing.  maybe i wasn't listening closely enough.
Comment: Robert if your wife belongs to a small parish, where most everyone knows everyone else, and strangers are rare and immediately recognized as such by the members, and the clergy, the Priest may feel that there is no need to voice the qualifications, but would do so if he saw a visitor he didn't know. As often as you've attended, I doubt you're a stranger, and as a Mennonite, you're baptized. I usually attend a large Parish, where the clergy don't necessarily recognize everyone attending, and I think the qualifications are not voiced, but printed in the service leaflet.
Comment: (St. Andrews, Colchester VT) the Rector makes it unmistakably clear to, she goes out of her way to communicate that the Communion Table is open to anyone who identifies themselves as a follower of Christ.
Answer: The Episcopal Church is in a period of evolution and discussion on this.
The official rule is "any baptized Christian."
However, a number of individual parishes and dioceses practice "Open Table" - that is, allowing anyone - even the unbaptized - to partake in Communion.
As a general rule, Episcopalians are much less strict about following rules than (for example) Roman Catholics, for whom restrictions on who can receive Communion are a major point of tension and scrupulosity.
Answer: I think it means if you think you're right with God, confessed your sins, received forgiveness and want to take Communion, do it.
Comment: It's best if personal opinions can be backed up with supporting evidence. Can you give any links to where the Episcopal Church says this?
Comment: According to Anglican doctrine, any baptized Christian, regardless of his or her denomination, is welcome to receive Communion in an Episcopal church. This practice is known as "open communion."   You can check that out on any Episcopalian church website.
Comment: I believe you, but if you're writing an answer here it's your responsibly to quote it for us.


Are Pokemon from eggs better in any way?

Question: Will a pokemon that I have evolved have higher CP/CP CAP than one of the same pokemon that I have found in the wild? Will a pokemon from an egg have higher CP/CP CAP than one in the wild?
Answer: According to this post on /r/TheSilphRoad by /u/Shaeress, Pokemon hatched by eggs tend to have improved IVs. This means that they will usually have a higher CP cap than Pokemon caught naturally.
/u/transphenomenal plotted the data, in this comment. The following is a roughly normally-distributed graph for naturally caught Pokemon, where 100 indicates a perfect IV Pokemon, with the highest possible CP cap, and 0 indicates a perfectly bad IV Pokemon, with the lowest possible CP cap.

This graph shows Pokemon hatched from eggs:
Answer: There isn't a difference. Every Pokemon of the same type (e.g. every Pikachu, Charmander, Squirtle etc.) Have very similar growth stats. The CP cap on every Pokemon is based on the Trainer his level. Catching a Pokemon with a higher CP simply makes training cheaper.
So far the only difference in growth stats is if the Pokemon is XS or XL which can be see in the Pokemon's detail page. XS increases max HP but decreases max CP, XL does the reverse.
Comment: @Schism - At the time this answer was first posted, we didn't have any hard data to show either way
Comment: This answer is not correct. Pokemon from hatched eggs have empirically and experimentally been determined to have higher IVs, which increases the CP cap.
Answer: No, however you are rewarded substantially more for hatching an egg than catching that same Pokemon in the wild - you receive a random amount of stardust that seems to range from about 500-1000 and a random amount of candies (I've gotten from 6 to 21). You also receive more experience.
EDIT: Research by people from TheSilphRoad suggest that Pokemon from eggs actually have higher IV's on average
Comment: I've hatched a bunch of eggs and I think I agree but I'm not 100% positive. One thing about higher IV's on egg Pokemon is wild Pokemon are harder to catch with higher IV/CP, whereas walking is the same "difficulty" no matter what. So the more esoteric/stronger Pokemon can be easier to hatch than catch.
Comment: That's a very interesting point. I only glanced at the "headline" of the research, but I'll take a more careful look when I get more time
Answer: Eggs are unique in Pokemon Go as some of the best Pokemon in the game only come from the rarest Eggs. Eggs, as you might guess, can hatch Pokémon. So, Eggs are the best way to Play the game.
Comment: Source for this?
Comment: I would say on the human side, if you have to do a lot of walking normally, then you have an advantage in hatching eggs over catching wild Pokemon. If your situation finds you spending a lot of time near a Pokestop where you can put lures and doing very little walking, then you might have more success catching Pokemon rather than hatching eggs. To maximize either you may have to spend some real money (on either Pokeballs or Incubators, as appropriate).


What should we do with the answers in the sandbox after the riddles have been posted on the main site?

Question: Yesterday, I believe I have read, on The Riddle Sandbox, that a riddle reaching a vote of 7 could make it to the main site. So far, so good. And I remember that the sandbox answer should be cleaned, leaving only the title of the riddle linked to main site, and the answer deleted. I could not find that mention today. What is the suggested course of action?
Comment: As a side note, it's likely that the sandbox will soon [no longer be required](http://chat.stackexchange.com/transcript/message/31992243#31992243) - it'll still be there for people who want help crafting their riddles, but not a requirement before posting riddles to the main site.
Answer: There is no official procedure.  The status quo has been to delete them from the sandbox when they're posted on main.  This has the benefits of:

Keeping clutter in the sandbox to a minimum (it has a lot of answers)
Keeping people who see the puzzle on main from going to the sandbox to try to find the answer (or clues to the answer).

The downside of this is that the revision history and comments of the riddle are lost, so no one can see how the riddle was improved and learn from the process.
Comment: @Laurent What's generally been done is to edit the answer so that it is a single line (something like "This riddle has been posted on the main site"), and then delete it. That way, the people who have the ability to view deleted questions won't have to scroll through quite as much content to find the still-active answers.
Comment: Understood. What about a separate Sandbox archive for that purpose?
Comment: So should I just delete it, or keep the title only before deletion?


iMac G5 works very loudly. How to fix it?

Question: I only run Safari with maximum 3-5 tabs opened and the machine makes noise like a vacuum cleaner making it very hard to work on.
Any ideas how to fix it?
Answer: If you think that the fans are running at a higher speed that they should, you could try reseting the SMU.
If the issue is just with the sound being too loud, then the best option would be to open the computer and clean the dust, mainly from the fans and the ventilation-related. Even more, overheat could have caused the fans to slightly bend, making some annoying noises. If that is the case, the only option would be to replace it with a new one. Replacing the thermal grease could be helpful too, if you've got overheating issues.


05 jeep wrangler rear sway bar connection is broken

Question: 05 jeep wrangler .The link that connects my rear sway bar to the rear end housing. What's it called. where can I buy a replacement. To be welded or fit in.
Comment: Can you present a picture of what's broken? Would help us provide an answer for you.
Comment: I downvoted because this question shows basically no effort on the part of the asker.  I also answered because they asked for help and that's what we're about.
Answer: Um...
Here's the Duralast Rear Sway Bar Link for your vehicle on AutoZone.com.  Part number EL159.  It's just called a sway bar link and in the description it specifies front or rear.
It's the same part whether you have the 4 cylinder or the 6.
On RockAuto.com, it's called a Stabilizer Bar Link and in the description it specifies front or rear.
Answer: Check with your local off-road or Jeep club, if there's one in your area, chances are someone has some sitting in the garage. Many people who off-road remove the rear sway bar completely. If you're driving on the road, and haven't made any other provisions, I wouldn't recommend doing this, but you might find someone willing to give you a sway bar link.


How to smooth out uneven drywall?

Question: I'm working to refinish a room and found that the wall underneath a window juts out, likely from a new window installation by the previous owner.  I want to make it smooth before painting; what's the best way to go about it? I was thinking drywall mud to feather out the difference along the height of the wall. But I wonder if there is a easier or better way to go about it?

(click to enlarge)
Answer: Is that tape bulging due to settling or water damage? Press on it and slide your fingers over it. Does it depress or make a hollow "shhh" sound? If so, you'll need to cut it away and re-tape.
If not, a wide skim is what's in order. You don't need to go full-height, though. Unless you want to improve the smoothness throughout, just go 12-16" out from the ridge. Use at least a 12" knife.
Apply mud and use a low angle and high pressure. You should basically see the mud scraped clean at the ridge, and the adjacent depression filled to the width of the knife. Leave as little mud on the wall as possible. The only sanding will be a very light surface prep. If done properly, no shaping happens while sanding.
Answer: It looks like a bad taping/mud job. Try sanding it down first to see if that's what it is. It's probably a flat butt joint so you'll need  4", 8" and 12" taping knives.

How to smooth out uneven drywall?


Application Password

Question: I'm looking for a simple application that password-protects selected applications. Can anyone help please? Just bought an Apple device after several years using Android.
Answer: To this day, there is no way to password-protect apps on iOS without jailbreaking. If you are familiar to rooting an Android device, it is somewhat similar to jailbreaking. If you already have jailbroken or want to jailbreak your Apple device, check out this link. If you decide to jailbreak, you can get password-protecting features through tweaks such as bioprotect or appscan if you have touchID. If not, there are similar tweaks that offer the same password-protecting features. If you aren't wanting to jailbreak your device, there is no other way. Hope this helps!

Application Password


How to prove that the source of a signal is truely alien

Question: A device is recovered from an impact site in the desert. This device contains bizarre, but not inconceivable, components and a simple interface. The interface is a black and white touch screen with a display showing many versions of "Press any key to continue. " scrolling by on the screen in every earthly language. After being pressed the device insists it is of alien origin and represents the first attempt to make contact between its creators and the people of Earth. The scientists working on this are skeptical and demand proof that the device is not just an advanced piece of hardware designed by another government to distract them from their work. Without other worldly hardware or materials how can the device convince the scientists it is alien via a simple text interface? For reference this takes place in the modern day.
Comment: Apart from the possible duplicate, in the title you are asking about the source of a signal, in the body about an artifact which can be used. Pick one for clarity
Comment: I assume by "impact site" you mean that the device fell to Earth as a meteorite?
Comment: Does this answer your question? https://worldbuilding.stackexchange.com/q/216217/30492
Answer: The easiest way to identify itself as of alien origin would be to provide a large amount of scientific information that is not available on Earth but which could be tested immediately and or in the coming years and decades.
For example, describing the theory of everything that physics has been searching for as well as a test that could be conducted to confirm that theory. It could also describe how to conduct further tests that can't yet be performed but are almost within our grasp (you need this part engineered to within one nanometer...).
Other possibilities include revealing astronomical facts that we are not yet aware of: The cavern of methane geysers on Titan, together with its exact location, the only outcrop of Thorium on Mars that would be classified as a rich ore on Earth, the exact orbital parameters of a range of bodies in the outer solar system that we have not discovered yet like the bizarre distant group of three small bodies that orbit each other. Or the neutron star that we can't see because it is obscured but might be detected by a space probe (https://archive.org/details/dragonsegg00robe/page/286/mode/2up)
With a careful choice and many examples it should be possible to give over whelming evidence. This could be confirmed today in some cases since they told us where to look or how to conduct the experiments and in the coming years when our technology has progressed sufficiently far.
Comment: To expand on your answer, some of the easiest things to check might be mathematical proofs of difficult statements. If the device contains proofs of a bunch of famous open unsolved math problems, like there being infinitely many Mersenne primes (primes 1 less than a power of 2), that could be verified by mathematicians quickly and enough of such proofs all together would be strong evidence of extra-terrestrial involvement.
Comment: My only concern with this is proving that another group of humans has discovered this but has not revealed it to the rest of humanity. If it's a neutron star we can't see than how can we verify it? If it's, say, a proof of the goldbach conjecture how can we say for certain that another group of humans didn't derive it and are using it to trick us into thinking they're aliens?
Comment: The neutron star might well be very dim and might only be visible if a very high resolution telescope was pointed directly at it or might only be detectable with a future telescope such as the James Webb Telescope. With one single item like the goldbach proof there might be some doubt but with dozens of different things from a range of different disciplines it would be increasingly unlikely that a group of humans had some how discovered so much. And with some things like the cavern of methane geysers on Titan there is no way that a group of humans could know it was there.
Answer: Show things only aliens might know
The aliens are bound to have a bigger understanding of the universe. They somehow cracked every language on Earth, so further knowledge isn't a stretch. In that vein you can go much further. As they know every modern language it is very likely they know the state of modern technology. With this they can direct scientists to fringe discoveries that aren't known yet.
For example, current scientists are very well aware what research is being conducted in space. These are limited resources that can't just have other discoveries. If you give them an accurate result and direct them to this new discovery, they will know that at least something with more knowledge than them is interacting with them. It might also predict some things accurately that we don't currently understand. There is a weird phenomenon around a certain star that is difficult to predict and explain currently (which some suggest is an alien structure). It might predict this accurately.
This doesn't need to be limited to space though. The aliens clearly do have some technological advantage with knowing all languages. That means they can divulge some scientific information and theories to further our understanding. By doing this they can be reasonably certain it isn't a hoax, as well as making any doubters still not dismissive of any further information.
It does make this a Pandora's box for the scientists. The question is if they should open it. I remember one telling of the Greek story where it was opened twice. The first time it brought something good, but it was warned to be never opened again. Pandora was curious and did so anyway, hoping for more good. All disease and death escaped into the world, making it a much worse place.
Following an unknown possibly alien intelligence their directions can be very dangerous. Even if it's only used for communication it can be hazardous thanks to the aliens manipulating, or humans just being humans and going crazy. Regardless of the possibility of a hoax, scientists would be careful.
Answer: It should be as simple as eliminating any possible scam motivation. This isn't easy though, because humans are inclined to create hoaxes for the sake of hoaxing.
However, when that happens, it is rarely more than a handful of people in on it. Most bigfoot/cryptid sightings are 1-3 people, and the crop circle folks had up to half a dozen. This device might only require a handful of people, but what of an analysis that confirms that no fewer than dozens/hundreds of humans would be needed to create it?
This eliminates the possibility of a hoax, I think. Relegating it to a project only nation-states could hope to complete.
Not just any, either. Only those with electronics fabs could do so without farming it out to third parties and prematurely exposing it. And what of the components themselves? Sure, they may be very similar to our electronics, but if this thing is using -8.2V and is some weird CMOS technology, at some absurdly wrong process node size... some of this stuff just becomes impossible to adequately fake. You realize that fakers couldn't make only one of these, because you often have to make thousands or even millions before you get good enough at them to put it into a retail-ready product, right?
Finally, you have to start to wonder just what the grift actually is. Even the most elaborate fakery is easily revealed by the fact that, if false, some other party has something to gain by it.
What would Taiwan or South Korea or China have to gain? Not much. These aren't nuclear weapons scientists that are being distracted, these aren't aircraft carrier logistics folks, they aren't economists who will be distracted. Just electronics nerds.
More so, they all have something to lose if they pull this stunt. They've given a valuable piece of hardware to their enemy who will then easily deduce some of their most top secret technology secrets just by examining the device. "Look at this Joe, China can crank out functioning prototypes of supposedly alien-technology as one-offs with a new CMOS tech at a really funky base voltage like you or I could scribble on a post-it-note, and then crash it into a crater in the Arizona desert!".
No, if they could fake this, they wouldn't do it.
The device itself does not have to prove itself, it has proven itself merely by existing.
Comment: /you have to start to wonder just what the grift actually is./  This is great.  It would also be great cinema.  The people listening believe the speaker, and one states that alright, they should go ahead and do what the machine asks them to do.   The speaker already did, last Thursday.   She figured she would wait for the rest of them to settle down and then would tell them and now she just did that too.
Answer: Show future knowledge.
If the device has ftl communication between it and the creators, then it by nature is a time travel device. If there are stellar events closer to them than you, they can report what the light from the stars does before you do, and relay this information.
Do computational tasks faster than them.
The earth scientists could also send them a problem which takes a long time to solve, but which can be easily verified, like how a protein folded, or the factors of very large numbers, used in crytography.
A much more advanced civilization presumably has much more powerful computers and can solve such problems much faster.
This could be used by scientists to earn vast amounts of money.
Provide precise measurements of things the LHC and other particle accelerators are measuring.
They presumably have better particle science than us. They could give predictions about the particle physics of particular reasons that no one has scanned, which could be verified later by the collider.
Answer: All elements on earth have a particular atomic signature. Ratios of elemental isotopes contained in a sample from the devices construction.
For instance if you made a knife on earth, and made and "identical" knife on mars. You could analyze the ratio of iron among all of the other present isotopes to identify not only which knife was Martian, but where on earth the earth knife iron was mined.
This is a widely used research method for things like identifying meteorites origin. Origin of gold or other precious metals in criminal investigations or commodity audits. archeological forensic studies.
Thus if they tested the device and it were show to have materials that match the isotope ratio of aluminum mined from a know source on earth, one would assume it would likely be a hoax.
Comment: Yes true, although not entirely fool proof since a cunning and devious person, organisation or nation with sufficient intent and access to materials would know this and could take material from different locations as well as materials exposed to neutron bombardment and blend them together to generate a false isotope signal that didn't match anything known.
Answer: I know that the question specifies that it shouldn't be other worldly hardware, but many of the answers talk about faster computation and similar things. As this fundamentally needs better hardware I'll assume that tech that we know is possible, but barely can't make is ok.
So why does it almost certainly need to be a physical thing? Very simple. Providing advanced mathematical or physics equations is not a proof. A until now unnoticed genius could have easily created them. They are not fundamentally impossible to be of human origin. Similar with any space data. Anything that we can verify from earth could have also initially been derived from earth. As such if it should be some sort of space data then it would need to be some kind of data about or solar system that needs a space probe at a specific point to measure something. As a result it would take years to confirm this, as space probe for interplanetar travel take very long to build. Occam's razor may be a good starting point, but it is not a proof. It is based on logic and can only deduce what is likely and unlikely, but just because something is unlikely doesn't mean it's impossible.
The following part will most likely sound like gibberish if you don't have a basic understanding of photolithography, but if by the end it sounds vaguely like a good solution I'd recommend to look a bit into the topic. If I also explained all of the necessary background knowledge then I'd still be here tomorrow. Plus there are plenty of great sources that explain the basics.
As such that only really leaves the hardware. And this is where it gets interesting. On earth there is currently only one company (ASML) that is able to produce the machines for UV/EUV lithography. This has been the case for over two decades now and no state actor has been able to reproduce these machines (china has tried very hard). During photolithography a special pattern needs to be placed in front of the laser, such that due to refraction and reflection in the material, only the intended part is actually being worked on. These advanced patterns are increasingly difficult to simulate, but not impossible. More complex patterns allow for smaller features on the wafers.
As such the computer could have the starting parameters for the given simulation, so that we can compute it ourselves to prove that it actually should result in that shape. Then the alien device could have these tiny features etched on its processor, as proof. This would work, as photolithography is one of those fields in science where we exactly know how things will look in future, but we are currently still in the process of creating equipment precise enough to create these things. In addition we also very clearly know the best technology that humans currently have and can claim with almost 100% certainty that there is no way for this to be of human origin.


Search - Only search for post meta field

Question: I know there are a lot of good plugins which extend the wordpress search but I want to do the opposite. I want the search only to return posts which have a certain value in a certain post meta field.
How do I do that?
Answer: I'm not quite sure this is what you want (because it is so ... easy), but all you need to do is add the following inputs to your search form:
<input type="hidden" id="meta_key" name="meta_key" value="YOUR-META-KEY">
<input type="hidden" id="meta_value" name="meta_value" value="YOUR-META-VALUE">

Or, if you want to trigger the search by hand, do it like so:
$search = new WP_Query(array(
    's' => 'YOUR-KEYWORD(S)',
    'meta_key' => 'YOUR-META-KEY',
    'meta_value' => 'YOUR-META-VALUE'
));

// EDIT
If you're dealing with a more complex setup, you might want to use a meta_query:
$search = new WP_Query(array(
    's' => 'YOUR-KEYWORD(S)',
    'meta_query' => array(
        'key' => 'YOUR-META-KEY',
        'value' => 'YOUR-META-VALUE'
    )
));

Or even
$search = new WP_Query(array(
    's' => 'YOUR-KEYWORD(S)',
    'meta_query' => array(
        array(
            'key' => 'YOUR-FIRST-META-KEY',
            'value' => 'YOUR-FIRST-META-VALUE'
        ),
        array(
            'key' => 'YOUR-SECOND-META-KEY',
            'value' => 'YOUR-SECOND-META-VALUE'
        )
    )
));

Comment: It seems easy but I can't leave out the s parameter. I really only want results with the right meta_value for a specific meta_key but when I leave out the s param I get no results. If I keep it but make it blank -> no results. If I assign the same value I assign to my meta value I get results but from my meta_value and results in the post text. It's nice that I can add the meta query but wordpress will still look for matches in the post text because of 's'


How is it possible to teach a neural network to perform addition?

Question: I am trying to understant how it works.  How do you teach it say, to add 1 to each number it gets.  I am pretty new to the subject and I learned how it works when you teach it to identify a picture of a number.  I can understand how it identifies a number but I cant get it how would it study to perform addition? I can understand that it can  identify a number or picture using the pixels and assigning weights and then learning to measure whether a picture of a number resembling the weight is assigned to each pixel. But i can't logically understand how would it learn the concept  of adding a number by one.  Suppose I showed it thousands of examples of 7 turning to 8 152 turning into 153 would it get it that every number in the world has to be added by one? How would it get it having no such operation of + ? Since addition does not exist to its proposal then how can it realize that it has to add one in every number? Even by seeing thousands of examples but having no such operation of plus I cant understand it.    I could understand identifying pixels and such but such an operation I cant get the theoretical logic behind it. Can you explain the logic in layman terms?
Comment: "having no such operation of plus..." why do you say this? Neural networks perform linear combinations of inputs, followed by non-linearities. Of course they have the + operation!
Comment: If you have a problem in understanding my answer do not worry, I was also a beginner and did not understand ReLu and stuff, you can always clarify
Answer: Welcome to AI.SE @bilanush.
Here's an example approach that might make things clearer. There are other ways to train a neural network to do this however.
In your earlier example with an image, you probably noticed that the network receives the image as a series of values, representing each pixel in the image. The network then learns which of a series of output neurons should be active in response to a given set of pixel values. Those output neurons, when read in an appropriate way, correspond to the correct label for the image. The difference between the set of outputs that should have been active, and the set that were active, forms the basis of the error signal that allows the network to learn.
You've probably heard that computers represent numbers with binary digits. So you could think of the number 16 as being: 00010000 in "8-bit binary". In 16-bit binary, this number would be 0000000000010000, and so on.
So one way of viewing your problem is a function mapping binary inputs to binary outputs (very similar to labelling a black-and-white image). For instance, the input 00010000 (16) should produce the output 00010001 (17). The input 00100011 (35) should produce the output 00100100 (36), and so on.
As before, you will have a set of output neurons. In this case, it should be wide as the set of input neurons. As before, the error signal is the difference between the expected inputs and outputs.
As to the question of how they can learn this function "without plus", in fact the individual neurons in a network perform just two operations: addition of their inputs, and a non-linear transformation of the sum. It has been proven that these are sufficient to learn any function from inputs to outputs, as long as the network contains 3 layers or more, and the as long as the middle layer is wide enough, but here it should be easy to see how addition might emerge.
Comment: Although it is a nice viewpoint, it will not work for unseen examples
Comment: @DuttaA I think you are mistaken: a sufficiently wide and deep network can learn this pattern and extrapolate to unseen examples. In particular, since the pattern is a series of full-adder gates, it can be done simply with a network that has depth and width proportionate to the number of bits. I agree with your answer that there are better approaches to solving this problem, but they may be harder for a novice to follow.
Answer: This is what we call a regression problem. Although @John has provided a novel method I do not think it will work since you are decomposing the number into its minimal representation, so teaching it will be quite tough due to long term dependencies like 0111111 will change to 100000, so you have to train on almost all examples, with 0 actual learning.
Let's see your problem from a different viewpoint. Why are you thinking only of integers? Your problem can be generalised to approximating this curve:

This is clearly an example of $W.T * X + B$. Single input node will feed into 2 output nodes of Leaky ReLu activation, and a bias node. The bias node will be your $c$ and the 2-3 Leaky ReLu's will adjust their weights to create a straight line. Training this might be a problem (with co-adaptation between nodes), but mathematically a solution will be achieved by this Neural Net structure.
Also it is better to train on real values also, for better and finer weight adjustment (although theoretically for a single independent variable $x$ you should just need 3-4 values to make this Neural Net learn, but who knows?)
NOTE: The approximation in the negative region might not be that great.


`rsync` verbosity using `--files-from`

Question: I'm working with rsync to archive old files on a running system. Thus, I use a command line of the form:
find /some/dir -various -conditions -printf '%P\n' | rsync -v --files-from=- --remove-source-files /some/dir user@archive_host:/archive/dir

This functions correctly and does what I want. However, even after passing -v to rsync, it does not print the files it transfers. I assume this would normally just exclude the command line arguments themselves; however, since the find command will produce an arbitrary, long list of files, I would like to be able to see them as the command runs.
How can I see a list of files transferred when using --files-from?
Answer: man rsync|grep progress shows you the parameter --progress

`rsync` verbosity using `--files-from`