Please explain basic concepts of a DLL file and its registration in Windows

Question: What is a DLL? What is it doing in our computer? Why we need to register it? Is DLL registration a common process of a single command? Is this installed/registered while we are installing a software?
Comment: Yes, it is a legitimate - though very basic - question. But there's nothing wrong with basic questions.
Comment: You may have a virus. Have you done complete scans? And what, exactly, is the registration error you're seeing?
Comment: Up voted because whilst its a basic question, its one I didn't know the answer to and I'm considered "the IT guy" in the office
Answer: DLLs are dynamic-link libraries:

Dynamic-link library, or DLL, is
  Microsoft's implementation of the
  shared library concept in the
  Microsoft Windows and OS/2 operating
  systems. These libraries usually have
  the file extension DLL, OCX (for
  libraries containing ActiveX
  controls), or DRV (for legacy system
  drivers).

See Dynamic-link library on Wikipedia.
Answer: dll stands for "Dynamic Link Library". As the name implies, it is a collection of functions (libray) that is linked to your program dynamically during runtime (compared to static linking).
Generally dll contain only function. "Modern" .NET dll contain normal .NET objects.
Dlls can be registered. This process (e.g. regsvr32 N:\ame.dll) makes this dll known for the operating system. As an alternative, the dll can be placed in the same directory as the executable or in a directory in the Path. A second alternative is to load the dll via Windows API (LoadLibrary()).
The normal procedure is to register the dll during installation or just copy it in the same directory as the executable.
Answer: A dll is a library of functions that can be used by other programs. Not all dll's need to be registered, that applies only to those that expose their fuctionality as COM objects.
Dll's can come from many places; a good number of them make up Windows as such, others come as part of various software that you install. Microsoft Office, for instance, registers dlls that exposes COM interfaces that allows other applications to incorporate functionality from the Office applications.
Answer: A program is a series of instructions.  Normally the computer will read and execute instructions one after another in series.
This is great, but most programs will do the same task at various times, or the same task with slight variations at various times.  Rather than rewrite the instructions of that task over and over, an option available to programmers is to package those instructions into a subroutine or function.
Then, instead of copying the instructions over and over, you tell the program to call that function and therefore save space.  Linking binds this function to all places that call it in the program, when the program is built.  The program is also easier to maintain since, if you want to change that task, you can change it one place and not all over the program.
Most programs have functions that are used within that program.  They are part of that program, loaded with it, and only accessible to that program.
But what if you have a great function (such as one that takes a date and returns the day of the week) and want to use it in many different programs?  Dynamic Link Libraries, or .dll files in Windows, allow this.  It's called dynamic linking because the linking occurs at runtime when program is loaded rather than at build-time when it is compiled (in this case it's called static linking).
You can package the function in a specific .dll, and then tell your main program you want to use, or import functions from that .dll.
Now, if you want to update what that function does, or fix bugs, you're in an even better situation since all you have to do is change the functions in one file and every program that uses it will be automatically updated.  The disadvantage is now your program depends on another file to work properly.  Usually the benefits outweigh the disadvantages for everything except emergency system recovery programs that need to work when you can't load anything from disk and such.
Answer: Let's not forget rundll32.exe. This Windows utility allows you to invoke a function exported in a dll. http://support.microsoft.com/kb/164787


74HC595 - Initial output voltage

Question: I've gone through the complete datasheet, searched SE and on google, but I cant seem to find this information:
Whats the output Voltage of QA..QH just after power-up when G (Output enable) is pulled low, but no data have been clocked into the shift register?
Answer: Unless otherwise stated, the outputs will be indeterminate. i.e. any output may be 0 or 1 which appears to be the case here.
This is why the SCLR pin (shift register clear) is provided, so that the outputs may be put into a known state which should be done prior to enabling the outputs.
Alternatively, a valid pattern may be shifted in to the device, but in either case this is normally done prior to the outputs being enabled (unless your circuit does not care).
This is normal for many parts.
In response to Crowie's comment, why are the outputs indeterminate is indeed a far more interesting question:
The output stage of a D flip flop is simply an RS latch as shown:

At power up, the two outputs start to rise, but at different rates and assume the inputs are also pulled to the positive power rail.
If the Q output rises faster then the lower gate will have two highs first, taking the \$ \overline Q \$ solidly low; this locks out the \$ \overline S\$ input and maintains this state until \$ \overline R\$ is pulled low.
Which of the outputs changes more quickly determines the initial output state, but for a given device it is simply unknowable and therefore we call the outputs at power-up indeterminate.
For completeness, here is the venerable 7474 clocked D flip flop:

With the exception of the PRE (preset) input, this is likely a close approximation to the latches in the '595.
Comment: Asking the question 'why are they indeterminate?' raises a much more interesting conversation :)
Comment: @crowie: indeed so. Answer updated with that information.
Comment: Good answer, we could go on all day about how it goes the heart of quantum mechanics and the inherent probabilistic nature of things but that would open up a whole new topic :)

74HC595 - Initial output voltage


activation function for neural network in R

Question: While creating a neural network in R, is it important to normalize the input data based on activation function? For Example - if the activation function is tanh input data should range from -1 to 1 and for sigmoid activation 0 to 1.
Answer: Your proposed normalizing scheme appears to try to normalize the inputs on the basis of the range of outputs for an activation function. This doesn't make much sense, since typical activation functions take any real number as an input.
I'm not aware of this method being used. Doing so seems to inhibit the outputs of common activations.
The sigmoid function $g$ gives outputs in $[0.5,1)$ for $x > 0$. If you normalize your inputs to be positive, you're giving up half the output rage of $g$.
The $\tanh$ function gives outputs in $[-0.76, 0.76]$ (approximately) for $x\in[-1,1]$. Rescaling the inputs to $\tanh$ in this way gives up almost 24% of the output range.
On the other hand, layer normalization is a popular option to re-scale the inputs to the next layer of the neural network. It has nice properties both in terms of regularization and speeding up training.


How to set system wide umask in alpine?

Question: This question may be same as https://stackoverflow.com/questions/10220531/how-to-set-system-wide-umask. But That is for debian based. I followed the instructions but I couldn't find any file named as /etc/pam.d/common-session. Also I don't know how to check that pam module packages are available or not ?
Answer: This is how I find out to set through gcos field. Feel free to edit the answer.
<code>apk add shadow
echo "session  optional  pam_umask.so" >> /etc/pam.d/base-session-noninteractive
adduser -D -u 1000 -G deploy -g "umask=0026" -s /bin/sh deploy
su deploy
umask  # This will output 0026 i.e your newly set umask value
</code>

How to set system wide umask in alpine?


Does a large sample size change any assumptions for a t-test?

Question: In reviewing the meaning of the Central Limit Theorem.  While doing so, realize that the two-sample t-test's test statistic has sample averages in it. If the representative samples of the patients being treated with each drug are very large, does this change any of the t-test assumptions?
Comment: Please note that the CLT says nothing about "very large" samples: it is purely a statement about a *limit,* with no implications about samples of any size.
Comment: Even if sample sizes are large enough that the sample means are approx. normally distributed, the t-statistic has a t dist'n only if numerator [containing sample mean(s)] is normal and independent of denominator [containing sample variance(s)]. Stochastic independence of $\bar X$ and $S^2$ holds only for normal data. // In particular, if data are exponential, $n$ needs to be quite large for $\bar X$ not to have a noticeably skewed dist'n, and $\bar X$ and $S$ both estimate the mean ; hence they are correlated. // In gen'l, you mustn't assume t statistic is t-dist'd just because $n$'s $> 30.$
Comment: Even if you're in a situation where the sample size is large and you're satisfied that the significance level was not too far off, you should still worry about power. If your sample is large because you're trying to pick up a small effect size (assuming you have a reasonable distributional model in mind for your variable), getting the actual significance-level close to your nominal $\alpha$ using a t-test isn't necessarily much use if you're throwing most of your power away (requiring a fairly large effect to be confident of seeing it). Better to use a good test for the situation you're in.
Answer: Illustration of distinctly "non-t" distribution of one-sample "t statistics,"
resulting from samples of size $n = 100$ from an exponential
distribution with mean $5.$ Simulation of 100,000 such statistics,
using R.
set.seed(2021)
n = 100;  m = 10^5
MAT = matrix(rexp(m*n, 1/5), nrow=m)
a = rowMeans(MAT)
s = apply(MAT, 1, sd)
cor(a,s)
[1] 0.717151   # not consistent with indep

t = (a - 5)/(s/10)
hist(t, prob=T, col="skyblue2")
 curve(dt(x,88), add=T, col="orange", lwd=2)
 LU = quantile(t, c(.025,.975))
 abline(v = LU, col="blue", lwd=2, lty="dotted")

Quantiles $0.025$ and $0.975$ of the resulting distribution (blue histogram bars) are far from $\pm 1.984.$ Results from one-tailed
tests would be especially problematic.
qt(c(.025,.975), 99)
[1] -1.984217  1.984217

With data from $\mathsf{Exp}(\mathrm{rate}=1/5),$ a one sided test
of $H_0: \mu = 5$ nominally at the 5% level would have
actual significance level either about $3.3\%$ or about $7.5\%,$
depending on sidedness.
set.seed(1121)
pv = replicate(10^5, t.test(rexp(100,1/5), mu=5, alt="g")$p.val)
mean(pv <= 0.05)
[1] 0.03202
pv = replicate(10^5, t.test(rexp(100,1/5), mu=5, alt="less")$p.val)
mean(pv <= 0.05)
[1] 0.07481

In the same circumstances, a two-sided test at intended $5\%$ level would
a have a true level of about $6\%.$
pv = replicate(10^5, t.test(rexp(100,1/5), mu=5)$p.val)
mean(pv <= 0.05)
[1] 0.05936

Comment: The exponential is fairly mild, too -- it's easy to find distributions that are more extreme (e.g. a gamma with small shape parameter, say one below 0.1, a lognormal with a shape parameter much above 1, a Pareto with shape parameter around 4 or smaller). I've seen (on more than a few occasions) real data that look somewhat like those.


Move user and mailbox from one active directory to another

Question: Our organisation used to be split across 5 sites with 5 separate domains (and physical locations).
We all use the same Office 365 tenancy and domain name (e.g. all of the staff across the 5 sites use firstname.lastname@example.com). Each of these domains use AD Sync to sychronise usernames and passwords with our shared Office365 tenancy.
If a user moves from one of these sites to another, how do we move their user account and mailbox in O365?
At the moment, we simply create a new AD account on the domain of the user's new site. We leave the Mail attribute blank and put them in an OU which doesn't synchronise with O365 so their e-mail account remains unchanged. We leave them as active users in the domain of their old site but obviously this causes problems as when the user's password expires after 90 days or they forget their password, we have to contact the user's old site to request a password change.
I'm struggling to clarify the terminology here. Essentially what I'd like to do is move the user from the old site AD to the new site AD and bring their mailbox with them. Is there a way to do this in PowerShell or something along those lines?
The only other thing I can think of doing is:

log the user in to Outlook
save their .PST
delete them from old site AD/sync
create them on new site AD/sync
log them in to new AD-synced e-mail account and import PST

Having to do that for ~20 users is a bit of a faff though. Does anyone have any more efficient options?
Answer: I have not validated this yet but I would try:

Migrate user using ADMT.
Disable and move the source account to a
non-syncing OU
Sync the source domain, it should remove the user and
    deactivate mailbox
Make sure the new/target user is active and in a
        syncing OU.
I believe Azure AD Connect should attempt to match the
            existing cloud user with the new user, and their unique ID"s should match.

If the above fails, and you get a new user created, you can initatie a restore request from the old mailbox into the new mailbox:
<code>New-MailboxRestoreRequest -SourceMailbox <Mailbox GUID> -TargetMailbox <Mailbox GUID>
</code>


Retraction onto a circle in a simplicial complex

Question: Let $X$ be a connected space homeomorphic to a finite simplicial complex. If there is an embedding $i: S^1 \hookrightarrow X$ which has a retract $r: X \rightarrow S^1$, then necessarily the first Betti number $b_1(X)$ is nonzero. Is the condition $b_1(X) \neq 0$ sufficient for a circle retract to exist?
Comment: It certainly depends on the embedding. See [here](https://math.stackexchange.com/questions/61366/surface-of-genus-g-does-not-retract-to-circle-hatcher-exercise)
Comment: @BerniWaterman I didn't mean to fix an embedding. The question is: If $b_1(X) \neq 0$, is there _any embedding_ whatsoever from the circle which has a retraction?
Comment: I see... interestingly enough, this statement cannot be generalized to higher dimensional spheres, and it is easy to find counterexamples: For $n \geq 2$, take $X$ to be a closed, oriented hyperbolic $n$-manifold. Then $b_n(X) > 0$, but $X$ certainly does not admit an $S^n$ retract.
Answer: As mentioned in Cihan's answer, this is a result of Borsuk. The proof is divided into two papers (see [1, Théorème 30] and [2, Korollar 11]).
A proof of this result (for Peano continua and rather difficult to read) appears in Kuratowski's book [3, S 57, III, Theorem 4].
In Section 1.1.3 (pages 8-11) of my thesis [4], I provide a proof for arbitrary (not necessarily finite) simplicial complexes which is based on Kuratowski's proof.
I sketch here a different way to prove this result for a finite simplicial complex $X$. First we take a 1-cycle in $Z_1(X)$ which represents a generator of a direct summand of $H_1(X)$ isomorphic to $\mathbb{Z}$. Then we need to take a representative of this cycle which is a simple closed curve. If $X$ is not a surface and $X$ has no local separating points (a point $x\in X$ is a local separating point if there is a connected open neighborhood $U\ni x$ such that $U-x$ is disconnected) it is possible to do this. The main idea is to consider three 2-simplices with a common edge and to use this to remove intersections one by one. It is easy to reduce to the case in which $X$ has no local separating points. Finally, surfaces are managed using the classification.
In every proof I know, it is necessary to subdivide the complex at some point. I do not know if it is always possible to find a subcomplex of the original complex homeomorphic to $S^1$ which is a retract.
[1] K. Borsuk. Quelques théorèmes sur les ensembles unicohérents, Fund. Math. 17 (1931), no. 1, 171–209.
[2] K. Borsuk. Über die Abbildungen der metrischen kompakten Räume auf die Kreislinie, Fund. Math. 20 (1933), no. 1, 224–231.
[3] K. Kuratowski. Topology vol. ii, Academic Press, 1968.
[4] I. Sadofschi Costa. Fixed points of maps and actions on 2-complexes, PhD thesis, Universidad de Buenos Aires, 2019. Available at http://cms.dm.uba.ar/academico/carreras/doctorado/tesisSadofschi.pdf.
Answer: Interesting question. I believe it is sufficient, let me sketch a proof.
Since
$$b_1(X) = \text{rank}(H_1(X;\mathbb{Z})) = \text{rank}(H^1(X;\mathbb{Z}))
$$
it follows from $b_1(X) \ne 0$ that $H^1(X;\mathbb{Z})$ is nontrivial. Consider the canonical bijection $[X,S^1] \approx H^1(X;\mathbb{Z})$, which associates to each $f : X \to S^1$ the pullback via $f$ of the fundamental cohomology class of $S^1$, denoted $f^*(d\theta) \in H^1(X;\mathbb{Z})$ (if I may abuse notation). Let $f : X \to S^1$ be any element whose pullback class $f^*(d\theta)$ is a basis element of $H^1(X;\mathbb{Z})$. It follows that there exists a continuous map $\sigma : S^1 \to X$ such that the $f^*(d\theta)$ evaluates to $+1$ on $\sigma$, and so $f \circ \sigma : S^1 \to S^1$ is homotopic to the identity.
Claim: One can homotope $f$ and $\sigma$ so that $f \circ \sigma$ is equal to to the identity on $S^1$.
Once this claim is proved, it follows that $\sigma \circ f : X \to \sigma(S^1)$ is a retract onto a circle.
Let me sketch a proof of the claim. First, by homotoping $\sigma$, we may assume that $\sigma$ is a concatenation of 1-cells of $X$, $\sigma = e_1 \cdots e_K$. Next, we may assume that for each 1-cell $e_k$, the restriction $f | e_k$ goes around $S^1$ monotonically, either forward, backward, or constant; this is true by the homotopy extension lemma. And then we can assume that $f$ is not constant on each $e_k$, or else we may do a small homotopy of $f$ near an endpoint of $e_k$, and then homotope $f$ to be non constant on $e_k$, and then apply homotopy extension.
Let $P$ be the number of local maxima of $f \circ \sigma$, which is equal to the number of local minima. The proof now proceeds by induction on $P$. If $P=1$ it should be clear that $f \circ \sigma$ is a homeomorphism, and then by composing with an isotopy of $\sigma$ we can make $f \circ \sigma$ the identity. If $P \ge 2$ then (after a cyclic permutation) we may assume that the restrictions of $\sigma$ to $e_K$ wraps negatively, to $e_1,...,e_J$ wrap positively, and to $e_{J+1}$ wraps negatively. Now we do a subsidiary induction on $J$: to reduce $J$, homotope $\sigma \mid e_{J-1} e_J$ to be monotonic, and apply homotopy extension.
Comment: In particular, this implies that for any (finite) CW-complex $X$ with $b_1(X) > 0$, there is always an element $[\gamma] \in \pi_1(X)$ of infinite order that can be represented by a simple closed curve... interesting...
Comment: Actually there are problems with this proof. The proof is invalid, for example, if $X$ is a wedge of two circles $a,b$ and $\sigma = ab$. I think it can be repaired (in the wedge of two circles, $\sigma$ should be $a$ or $b$, just not $ab$ or something more complicated). But I have to think about it more and I'm out of time for the day.
Answer: The answer is yes, via results of Borsuk and Čech from the 30's. The generality where the sufficiency holds is remarkable, but the route is rather undirect this way. As I'm answering my own question, I will wait for some time before accepting this as an answer. There should be a shorter and self-contained proof, at least in the triangulable case, along the ideas Lee Mosher has outlined in the previous answer.
Definition: A space $X$ is called a Peano continuum if it is compact, connected, metrizable, and locally connected.
This terminology is due to the famous Hahn-Mazurkiewicz theorem, which says that every Peano continuum can be realized as a continuous image of the unit interval $[0,1]$.
Definition: A connected topological space $X$ is called unicoherent if for any decomposition $X = A \cup B$ with $A$ and $B$ closed and connected, the intersection $A \cap B$ is also connected.
Theorem: Let $X$ be a Peano continuum. The following are equivalent:

The first Betti number $b_1(X)$ is nonzero.
$X$ is not unicoherent.
$X$ admits the circle $S^1$ as a retract.

Čech proved 1 $\Rightarrow 2$ as Theorem B here.
Borsuk proved 2 $\Rightarrow$ 3 as Theorem 30 here. And 3 $\Rightarrow$ 1 is okay.
Comment: I believe that $b_1(X) \neq 0 \Leftrightarrow X$ has $S^1$ retract should also hold for not necessary compact, but reasonably well behaved, simplical complexes (for example, smooth manifolds).
Comment: Also, do you know if there exists english translations of those papers ?
Comment: @BerniWaterman I don't, unfortunately. But, to my surprise (I don't know German or French), it wasn't terribly difficult to find my way through those papers using Google translate.


Why is the value of "a" is positive instead of negative in Van der Waals equation?

Question: Higher value of a means higher atttraction force between molecules. Attraction force causes the pressure to be less than expected. Now the actual pressure becomes $P + \frac{n^2a}{V^2}$ .
Which means if a increases the neat pressure increases too. But isn't it the other way around?
(I assume here P is the pressure exerted on the wall of the gas container considering there is no intermolecular force)
Answer: You understand the chemistry: intermolecular attraction forces cause the pressure to be less than expected. The problem here is with the math. Though unintuitive at first sight, a positive $a$ leads to a negative correction to pressure. Let's look at a numerical example.

Assume that the pressure inside a certain container is $50$ atm with the ideal gas approximation and $45$ atm with the van der Waals equation of state. Then $P_\text{ideal} = P_\text{vdW} + 5$.

In other words, the corrected pressure is $P_\text{vdW}$, not $P_\text{vdW} + a\frac{n^2}{V^2}$.
Answer: The formula is good because it is correct in most of the regions and the parameters make sense. It is attractive because it both describes behavior of gas and approximate behavior of a liquid.
This formula has a problem in a region that corresponds to phase transition (boiling of a liquid). To account for that region correctly you need a function that is constant within some range and changes within other ranges.
Complex analysis (a branch of mathematical analysis) has a theorem that proves that you cannot have an analytical function that is constant on one interval and changing over the other intervals.
This sort of functions exist, but they are not analytic and behave poorly (hard to work with).
As a free bonus it turns out that the "strange" region describes behavior of overheated liquid and overcooled gas. Those two have different behavior at the same temperature.
Comment: I downvoted this answer because it is irrelevant to the posed question.


Remove redownloadable song form Itunes

Question: how do I remove a redownloadable song.  I down loaded a song and it keeps charging me for it per month.  I want to remove it.
Comment: What is a `redownloadable song`?
Answer: You may have subscribed to Apple Music, and are getting a charge for the monthly fee.
To cancel your subscription, follow the advice from this Apple Support article:

On the Home screen, tap Settings.
Tap iTunes & App Store.
Tap your Apple ID at the top of the screen.
Tap View Apple ID. You might need to sign in.

Under Subscriptions, tap Manage.
If you don't see a subscription in iTunes and are still being charged, make sure that you're signed in with the correct Apple ID. If so, you might have subscribed directly with the provider and not through iTunes. In this case, contact the content publisher or app developer directly to cancel your subscription.

Tap the subscription that you want to manage.
Use the options to manage your subscription. You can choose a different subscription period, or turn off Automatic Renewal.
Turn off Automatic Renewal to cancel a subscription. Your subscription will stop at the end of the current billing cycle.

Remove redownloadable song form Itunes


Unorthodox constructive reasoning: The Kleene Getaway

Question: KG (the Kleene Getaway) is the name I improvised (in my answer to a question on MO on constructive Perron-Frobenius) for a constructive principle which enables the direct constructive use of a classical result in the following situation:
Suppose T is a classical theorem of analysis/topology/... provable in a formal system $\mbox{F}$ which is constructively 'sound' in the sense that $\mbox{F}$ is constructively equiconsistent with its constructive subsystem $\mbox{F}$$_\mbox{c}$, obtained by leaving out LEM.
Now suppose that we have an $x$ and a property $P$ such that:
a) $P(x)$ is constructively decidable (so we can decide $P(x)$ or $\neg(P(x)$)
b) $P(x)$ holds classically by T
Then KG states that $P(x)$ holds constructively as well.
Proof: The proof is actually quite simple, on the proof-level of the formal system, since $\neg (P(x))$ is impossible by b) and the equiconsistency of $\mbox{F}$ and $\mbox{F}$$_\mbox{c}$

Question 1: does anyone know of a publication where this principle is mentioned explicitly, and (hopefully) given a name?
So far I seem to be the only one using it, especially as a shortcut in online discussions (see the MO-question I mentioned above) to quickly establish that something can be proved constructively.
Question 2: Almost always when I use it, it is met with a mixture of disbelief or disapproval. Is there a better way of presenting it, to overcome what I believe to be miscommunication?

Some background:
One of Kleene's highest achievements in my opinion is one of the least known: his seminal work The Foundations of Intuitionistic Mathematics - especially in relation to recursive functions (usually abbreviated FIM).
In FIM Kleene developed a formal system (also called FIM...) and 4 years later, through function realizability methods, he showed equiconsistency of the classical extension of a basis theory of FIM and the intuitionistic extension of that basic system.
So, unnoticed by many: intuitionistic mathematics is as sound as classical mathematics, in the comparative realm of say separable analysis, topology, etc.
Answer: See Michael Beeson, "Some Relations between Classical and Constructive Mathematics", Journal of Symbolic Logic 1978, on JStor.
Unfortunately, he doesn't give these principles a good name, and in my experience, people distrust this metamathematics unnecessarily.
Comment: The login finally succeeded... Wow, this is *precisely* what I was hoping for. What a wonderful article!! Finally I can use KG with a reference, this is very helpful Matt!
Comment: I've accepted your answer because it obviously is what I'm looking for :-). Unfortunately I can't login to my JSTORaccount because their loginservice is down, pff. So I can't really comment more, please have some patience. Thanks again, cheers Frank.


Alkali metal carbonates, their thermal stability and solubility

Question: From Li to Cs, thermal stability of carbonates increases. From Li to Cs, due to larger ion size, hydration enthalpy decreases. So, solubility should decrease from Li to Cs. But, experimentally, order is reverse. I cannot wrap my head around this.
Comment: Yes. Even ignoring entropy (to a first approximation we might assume that the entropy change is constant for all the metals), solubility depends on both lattice energy and hydration enthalpy so you can't just look at one trend. While it's more favourable to solvate Li+, it's also harder to break up Li2CO3 into its constituent gaseous ions. Just so happens that here, the lattice energy term predominates.
Comment: It's difficult to say. The entropy term also has to be split up into lattice breakage (probably roughly the same for all metals) and solvation effects. In the absence of any data my hypothesis would be that Li+, being the smallest (highest charge density), will lead to the greatest ordering of the solvent molecules around it. Consequently the entropy change would be the least positive. This effect is also reflected in the large hydrated ionic radius that you speak of. (I don't have data and I'll take your word for it.)
Comment: Order of what is reversed?
Comment: Found my mistake (probably) thermal stability is related to decomposition, I wanted to break lattice into gaseous ions, whose energy change is given by lattice energy. Both |hydration energy| of constituent ions and lattice energy of M2(CO3) decreases from Li to Cs as in Li>Na>K>Rb>Cs. Entropy change plays a big part too here. I meant order of solubility of M2(CO3) in water.
Comment: A side question, as the hydrated ionic radius is highest and mobility least for Li among the above compounds, would Li2(CO3) have least entropy change of solution?
Answer: Lattice energy is also decreasing down the group. hence thermal stability is decreasing. But since lattice energy is decreasing squarely and hydration energy is decreasing linearly, the effect of decrease in lattice energy is higher than the effect of decrease in hydration energy. So if energy required to break lattice is very less, then the lattice of the bottom elements in alkali group will break easily compared to the lighter ones. Thus if not lattice form, then they prefer the aqueous state and hence they love to stay dissolved and not form lattice. So solubility increases.


How do I add Paging to a sharepoint DataFormWebPart?

Question: I'm creating an archive of news articles in a sharepoint publishing site.  users can browse or search the archive.  browsing is a simple list of article dates titles.  I'm using the DataFormWebPart to display the contents of the Pages (articles).  as there are thousands of articles, i'l like to show maybe 50 on a page.  I see no built in paging on the DataFormWebPart.  I'm seeking guidance on the proper way to add paging.  I'm feeling like the XSL template is the proper place to start.
Answer: If you look at the page using the sharepoint designer in 'design' mode, you can click the common task arrow ( > ) and customize the data view properties.
One of the tabs will be about 'paging' and you can set how many items per page.
Hope this helps!
Answer: The XSL template is where you need to start.  Unless you are dealing with multiple data sources setting a list as the datasource on a new DataFormWebPart in SharePoint Designer (SPD) will create an XSL template with paging (10 items default).  You can then review and edit the XSL if you want to modify the appearance or operation.  After the initial XSL template take a look at the webpart properties in either the browser or SPD.  There are some other settings (e.g. async) that you may want to alter.  The paging technically works with mutiple data sources but it is only on the parent data source.  If the child count is large it often times is too large to see the paging control in SPD.


Any good practice material for expected value and variance?

Question: I am trying to learn more about probability mass functions, density functions, expected value, and variance. Are there any online materials or quizzes (with answers and explanations) that I can use to test my understanding?
Answer: In my experience teaching intro probability courses, many online instructional
materials (even trendy and popular ones) are quirky as to content or hastily written without proofreading. (I have spent many hours over the years
dealing with student confusion due to reading poorly written online material.)
I don't want to deprecate online probability instructional materials en masse, but I
don't have any suggestions that I can recommend with confidence.
If someone else has a recommendation based on personal experience, perhaps
it will appear in another Answer.

If you are looking for something that's free online, then I can suggest
Grinstead and Snell's 'Intro. to Probability'. It is available in book form,
but you can find a free PDF online. Look at Chapter 6.
There are many exercises at the end of the chapter, but I don't know if an
answer book is available. However, there are many worked examples. You can
choose to view some of them as problems, if you don't peek at the solutions.
Grinstead & Snell is competently written and well-reviewed. It has some
examples that are not standard for elementary texts (which was sort of the
point of their writing project). Also, the book uses simulation in some
places where a traditional text would not. However, there are many very traditional
examples, arranged in a reasonable progression of difficulty. I suggest you just skip the examples that are not to your taste.
Also, remember that it is Chapter 6, that deals with expectations and variances, so you might want to browse Chapters 1-5
to make sure you have the appropriate background material in mind.
Comment: If you can recommend a good book that I can order from Amazon or something I can go that route as well. I just figured I may as well try the free route first. But if there is a fantastic resource out there I can buy as well, I am all ears
Comment: If you can be explicit about your mathematical level and your reasons for studying probability, you might get a variety of useful recommendations-- before you spend money. There are dozens of possibilities across math level and degree of application.  Meanwhile, I think Grinstead and Snell is worth a look. Google `Grunstead Snall Dartmouth Probability`.
Comment: I'm self-taught so I am not sure how to express my math ability. I just want to learn everything I can. To better problem-solve, analyze distributions, analyze data, understand statistical analysis, understand probability better, everything. Number theory, computer science, calculus, probability, everything.
Comment: Differential and integral calculus? Multivariable calculus? Real variables? Measure theory? // Interested in pure math? Grad study in probability? Job in quality management, applied probability, actuarial science, finance? 'Everything' is probably not attainable.


Words without simple synonyms

Question: Is there a word or concept that describes words lacking simple (e.g. less pretentious, less technical, less subjugating) synonyms, or more generally words without single-word synonyms. I'm looking for lists of words that defy "plain-English" translation, in an effort to identify "essential" vocabulary. I'm thinking of the vocabulary equivalents of least-common denominators.
Comment: I don't know that this term is used for this purpose, but the word "irreducible" comes to mind. Also, fractions have "simplest forms," so you borrow that term.
Comment: Another word that comes to mind is _primitives_. It would probably help if you gave examples of the words that you're asking about. Are you thinking of words like _the_ and _be_?
Comment: *asynonymous* is used occasionally, sometimes with meaning "having no synonyms" (in genetics articles), and sometimes with meaning "not synonymous" (in logic articles)
Comment: I think he means words like *demonstrable*, which is difficult to replace with anything less grand without losing the meaning.
Comment: Such words would have remarkably specific, if not unique meanings, so maybe "remarkably specific/unique descriptors."
Comment: FYI: Special English (https://en.wikipedia.org/wiki/Special_English) and Basic English (https://en.wikipedia.org/wiki/Basic_English)
Comment: If the word has no synonym but must be explained, how could it be "essential"? Do you have a simpler word for "essential"?
Comment: Yes, there is such a word but it's 187 characters long and can only be pronounced in Swahili.
Comment: Are you sure this isn't one of them?
Answer: Many of such words would be quite technical, not "primitives" or least-common denominator; and would not be essential to a " basic" vocabulary.  obviate, parallel, isosceles, gastroenterologist, pahoehoe, anemometer, sphygnomometer, pyroclastic, enantiomer....  These are not "irreducible", but it takes more than one word to " reduce" them. (of couse, now someone will come up with one-word synonyms just to refute my offhand examples).
I would suspect that invented languages would have a lot fewer synonyms than English, which has in many cases inherited or adapted multiple terms for the same thing from various languages.
Here's an article about Ithkuil, an invented language ostensibly much more efficient (more precise, yet more concise) than English.
http://www.newyorker.com/magazine/2012/12/24/utopian-for-beginners
Answer: I've been looking for a list of words that don't have synonyms. I've had no luck. I have however researched the idea for about two years now and the closest I have gotten to previous work on the matter was by the linguist Morris Swadesh. He is a little dated on his work.
Wikipedia has an appendix of "Swadesh lists" in various languages: http://en.wiktionary.org/wiki/Appendix:Swadesh_lists
These words tend to lack synonyms in their respective languages. Words like colors or body parts. There are verbs as well though.
Answer: There is the word "Univocal" but I'm not sure if this is what you mean.

OED
1.b. Of terms, etc.: Having only one proper meaning or signification; admitting or capable of a single interpretation or explanation; of which the meaning is unmistakable; unambiguous.Opposed to equivocal

adj. 2. Now esp. in Logic.
1843   J. S. Mill Syst. Logic I. i. ii. §8   A name is univocal, or applied univocally with respect to all things of which it can be predicated in the same sense

Most prepositions have no true, or even close, synonym.
However, given the nuances of English, there are very, very few "true synonyms". English words "carry baggage" (often depending on the language from which they came), e.g. king is not identical to monarch; quick is not the same as fast, etc.  Also context plays an important part.

Words without simple synonyms


Understanding 'Assignment'

Question: I wonder why we use 'assignment' the way that we do? When we state with a definition expression that some variable takes some value, what does this mean? Is there a sense of time in the frame of Mathematics and Logic where certain names refer to certain values? Or is this essence of 'change' wrong? Should we see 'assignment' as really expressing a function that maps between different 'variable spaces' so we are seeing the mapping for when we interpret the value of a particular number in place of our placeholder for a 'name'? In something such as computer-science the idea of assignment, is just that, something that's set until you change it, but the concept of 'assignment' in Logic and Mathematical contexts seems much less clear, what is the best way to understand it? Does the variable name become a valid way to refer to a particular value under a particular 'assignment' and when is this true?
Comment: In programming, "assignment" usually refers to something that happens in time, or at least in sequence. In logic, it means something more like "definition".
Comment: It is only a technical term for the semantic operation that gives a reference to a term.
Comment: @MauroALLEGRANZA would you recommend somewhere to find out more about a formal way of viewing it, the way we treat it and the language we use? such as the for... and when... statements?
Comment: See e.g. [Tarski's Truth Definitions](https://plato.stanford.edu/entries/tarski-truth/#193ProSemCon)
Answer: Answer
Well, a glance at the etymology of 'assignment (Etymonline)' gives us one clue:

late 14c., "an order, request, directive," from Old French assignement "(legal) assignment (of dower, etc.)," from Late Latin assignamentum, noun of action from Latin assignare/adsignare "to allot, assign, award" (see assign). Meaning "appointment to office" is mid-15c.; that of "a task assigned (to someone), commission" is by 1848.

While we tend to think of assignments as a synonym for tasks, 'assignment' is also a synonym for order, as in imperative. Thus, whether in a mathematical context or a computer science context (they're really both computation anyway), an assignment is a command. On a computer, int x:=5; is a sentence to order the compiler to associate the identifier a with the integer value of 5. In mathematics, historically, the order is expressed with the delightful imperative 'let' as in Let x be 5. Remember, in mathematics, logic, and programming, in essence an algorithm or a proof is nothing more than a series of operations, and the person writing it is instructing the compiler or math partner to follow a series of steps.

Does the variable name become a valid way to refer to a particular value under a particular 'assignment' and when is this true?

Absolutely. The variable name or identifier, if you prefer, is a valid way to refer to the value assigned anytime after the assignment. The only real difference between instructions to a math or logic student and that to a compiler is that math and logic teachers tend to presume steps can be ordered in a way that a programmer usually cannot and must make explicit. That is, compilers are notoriously finicky because they do exactly what you tell them to do. For instance, to get a compiler to assign values associated with an identifier like a ten times, one generally has to use syntax like for( a:=0; a<11; a++){} which very clearly sets up an initial assignment a:=0 for the first iteration, then sets up an explicit Boolean conditional to continue a<ll; a++ 'at the end of every iteration of the block, increment the value by one as long as the variable is less than 11'. On the other hand, a math teacher might just say, let a start at 0 and continue the process to 10. Whereas a compiler has strict rules which govern it's iteration (because it's a mindless Turing machine), a human being can imagine all sorts of ways to do an assignment that might not be what the math teacher has in mind.
But, this isn't really an issue that inheres to 'assignment' per se, but one that is more general to the difference between giving an order to an interpreter in a BNF syntax and using natural language to asking a human being to do something.
Comment: As we know, humans don't always do "exactly what you tell them to do".
Comment: @ScottRowe lol I'm a parent. I know. But in a theory of physical computation, a human computer is an idealized person that does. :D
Answer: Assignments are typically modeled as functions, both in mathematics and computer science. In particular, there is not really a notion of "time", or at least does not have to be.
For example, consider model theory. In (first order) model theory, a variable assignment is a (total) function from the variables to the domain. We use variable assignments to recursively define the notion of satisfaction. In particular, we say that a model M, variable assignment s satisfy P iff M, s' satisfy P for every s' that agrees with s everywhere except possibly at v.
Consider also computer science and take an imperative language. An assignment is a command rougly of the form "x:=a". One typical model of this command is as a function from states to states, where a state can roughly be modeled as a function that takes sets of identifiers to the domain. In this example, we might have that stX was at first 3. After the command, stX is now a.
The upshot is this: what assignment means varies from context to context. If you're in a formal setting, make sure you are clear on that particular usage.

Understanding 'Assignment'


Windows 7: the product key you entered does not appear to be a valid windows 7 product key

Question: While bulk activating OEM Windows 7 PRO x64 products (we re-image the PCs every three months or so), I always have issues with a couple of machines.
The issue I'm facing now is that it reports "the product key you entered does not appear to be a valid windows 7 product key", even though this is the key that is printed right on the sticker of the PC.
When this happened previously, I just chose 'Activate by telephone' and everything was fine. However, that option is greyed out now. What I've tried:

running 'slui.exe 4' in an elevated command prompt, this just opens up the option dialog, in which 'activate by telephone' is greyed out.
'slui.exe 04', 'slui.exe 5', etc.
net stop sppsvc, and then executing the commands "CD %windir%\ServiceProfiles\NetworkService\AppData\Roaming\Microsoft\SoftwareProtectionPlatform | REN tokens.dat tokens.bar |net start sppsvc | slui.exe"

This is all not working. Can I call Microsoft directly/other solutions?
Answer: running the following commands worked:

slmgr /ipk "product key"
slmgr /ato


Can College of Lore magical secrets be traded at level up?

Question: The Player's Handbook says that a spell can be traded at level up for any other spell in any slot that you can cast. I'm wondering if I can trade a spell learned from magical secrets and if the new spell I get from the trade can be from any class. There doesn't seem to be any specific mention in the rules.
Answer: Well, there's good news, and there's bad news. The good news is that you can trade away the spells from Magical Secrets. The bad news is that you can only trade them for bard spells.
The rules on trading one of your spells known for another say that:

Additionally, when you gain a level in this class, you can choose one of the bard spells you know and replace it with another spell from the bard spell list, which also must be of a level for which you have spell slots.

So, you can only trade away bard spells for other bard spells. However, Magical Secrets says that:

By 10th level, you have plundered magical knowledge from a wide spectrum of disciplines. Choose two spells from any class, including this one.
  A spell you choose must be of a level you can cast, as shown on the Bard table, or a cantrip.
  The chosen spells count as bard spells for you and are included in the number in the Spells Known column of the Bard table.
  You learn two additional spells from any class at 14th level and again at 18th level.

Since the spells from Magical Secrets count as bard spells for you, you can trade them for other bard spells when you level up. This doesn't change the fact that you can only trade bard spells for other bard spells, though, so the new spells you get from trading will have to be bard spells.
As one final caveat, the spells you chose with Magical Secrets count as bard spells for you, so if you trade one of them away, you can later trade something else away to get it back.
Comment: Just for reference, the above point Miniman is making was also confirmed by Jeremy Crawford:  https://twitter.com/SalmonSquire/status/658005274956079104
Comment: It seems that Crawford is simply stating that spells gained from Magical Secrets count as Bard spells not that they can only be traded for spells on the Bard list. I think the OP's question is whether they can trade up, i.e. swap the 3rd level Wizard spell they learned with Magical Secrets to a 5th level Druid spell upon gaining 9th level. I don't think Crawford's tweet is clear one way or the other on that unless I'm missing something.
Answer: RAW says you can trade out the spell (yay!) but probably only for another Bard spell (boo!).
That's according to this Tweet from Crawford that specifies that since Magical Secrets spells count as Bard spells, you can trade them out when you level up, but only for a spell on the Bard list. Personally however, I think this is a pretty vaguely worded ruling and doesn't really answer the user's question.
That being said, this is a very unfun ruling and this question isn't tagged RAW.
Magical Secrets is one of the most awesome things about Bards, and makes them tremendously powerful. Being able to take any spell from the book means you can do things no other class can do, like grant your high DPR party member an extra attack using Haste while also preventing some terrible spells being cast on them using Counterspell (enhanced even further using Jack of All Trades). Or taking Wish at 18th level and making your DM hate you.
At the same time though, having all the good spells from every class makes the rest of the party pretty jealous. It's bad enough for the PHB Ranger to not get 5th level spells until 17th level, it's even worse when the party Bard can take all but two of your spells you choose the next time you level up.
I've found that the most optimal solution is this: if a Bard wants to replace a spell they learn via Magical Secrets at a lower level, they can only choose a new spell that they would have been able to learn at the level they were at when they chose it.
So if a Lore Bard chose Counterspell and Booming Blade at 6th level using Lore Bard's Additional Magic Secrets feature but later learned Booming Blade through the Magic Initiate feat at 8th level, they would only be able to replace Booming Blade with a spell of 3rd level or lower, because that's the max level they could learn at Level 6. (Shield is a good choice for this by the way)
Comment: Based on the Tweet it looks like that spell permanently counts as a Bard spell for that character, so they cannot take a new Magical Secret Spell, but they can take that spell back if they removed it

e.g. The Bard, Alex, took Find Familiar as a Magical Secret, but due to never needing to cast it again as it is only used for social situations, Alex had removed the spell and learned another Bard Spell like Charm Person, but in the future after levelling up, Alex lost their Familiar, they can replace Detect Magic with Find Familiar later on due to it being a Bard spell for Alex
Answer: You can trade spells from magic secrets for another spell from any class. The only thing you have to do is replace 1 secret for another, so your magical secret spell number remains always the same (e.g., at level 10 you have 2 secrets, at level 14 you know 4, and at level 18 you know 6 secrets).
Comment: Welcome to the site, sotiris!  You might wonder why you are getting downvotes.  This is a Q&A site, not a forum. We generally expect that answers are supported  by rules (when possible) or user experience (when rules aren't sufficient to answer a question).
Comment: Flaggers: this is an answer. It's attempting to rebut the other answer, but by chance or design it does end up actually attempting to answer the question. Being unsupported or obviously intended to reply to another answer doesn't *alone* qualify a post as Not An Answer, since NAA cares only whether an attempt at answering has been made. As long as the post contains an answer, mods can't with honesty accept a Not An Answer flag.


Mounting IMU on Raspberry Pi

Question: I want to order an IMU like this : https://www.raspberrypi.org/blog/real-time-orientation-display-with-the-minimu-9-v2/, and mount it on the mainboard so that fits mecahnically and is stable. I found a way using AdaFruit GPS ( https://www.adafruit.com/product/2324 ) and sticking the IMU inside the holes and connecting them to the various pins ( Vdd, SDA , SCL etc. )
However I do not want any GPS.
Is there any other solution? What is HAT by the way in Adafruit?
EDIT, after some downvotes ( misunderstanding maybe ) for my answer:
Is there any solution, wherein there is any alternative to Pololu and which fits mechanically on the Raspberry Pi.
Comment: I'm not convinced this is a Pi specific question.  You want to know how to mechanically mount one object to another object which is a fairly generic question.  I suspect that any answer given will be dismissed as not quite perfect for your situation.  Does the Pi have a mounting hole?  Does the IMU have a mounting hole?  Why not use them?
Comment: @joan : i have written in my question the specific objects. I dont know how did you come to a conclusion that I want to fit any object to any object !? I have already found the answer .. See my answer below .
Comment: @joan I think the Pi's mechanical properties should probably be given equivalent weight to its electrical properties - mounting hole arrangements can be significant for some applications (although you can velcro your way out of just about anything).
Answer: My initial guess would be to duct tape it to the back. I can't find any imu hats.
And a HAT is something you can put on your pi, so it stays like this.
Answer: An alternative to Pololu is Sense-HAT
Luckily Sense-HAT has all the sensors that the Pololu-IMU has and also mechanically fits perfectly on the controller.
Hence, the Sense-HAT could be a good replacement to the IMU Sensors from Polulu MinIMU-9 v3.
Comment: While I'm pleased that you found an alternative approach to your issue, this is very much not the answer to the question 'How do I attach a Pololu MinIMU-9 v2 to a Raspberry Pi?'. If you plan on answering your own question there has to be some amount of logical consistency between Q & A. We do not play ['What's in my pocket?'](http://tolkiengateway.net/wiki/Riddles_in_the_Dark) here.
Comment: @goobering : huh.. i wrote the question because i didnt know about this board at all. As I wrote in my answer, that its an alternative and alternatives are also answers ! Atleast I am sure, the answer would benefit one or the another someday.. So kindly stop accusing with "Whats in my pocket" and avoid the unnecessary pain of downvotes..
Comment: @infoclogged: It still doesn't answer the question you proposed, at all.
Comment: @Jacobm001 : I have asked for alternative solutions.. Just not for mechanically mounting, but also for if there is any alternative solution to achieve my goal - and the goal was to get IMU data from raspberry. Read the question properly dude, that I wanted a HAT which does not have a GPS..So, avoid the pain of downvoting unnecessarily.

Mounting IMU on Raspberry Pi


Moving image attachment from post to another?

Question: How to move image attachment from post to another (not to "Remove Permanently" and Re-Upload) ?
I'm using WordPress 3.5.0 and I have a thousand images to process. Is there a built-in function for this ? or is there a WordPress plugin doing this ?
Comment: I don't know if the plugin works anymore, but check out [Bulk Change Attachment Parent](http://wordpress.org/extend/plugins/bulk-change-attachment-parent/).
Answer: As far as I know, you'd have to use a combination of built-in functions to achieve this. If there is a plugin, you'd have to research for "Bulk parent" or "Bulk re-attachment".
Unless you have a logic connecting those posts, I think you'd have to do it post by post. Be it with PHPMyAdmin (changing the post_parent column values for all post_type with attachment value). Be it with an already existent or custom built plugin.
One solution is creating a Meta Box, where you'd enter the target post ID and all attachments from the current post would be moved to the new post.
It can be built researching the following queries:

+add_meta_box +save_post +input +text is:answer.
+get_children +post_parent is:answer.

There is a very nice and small technique from WPEngineer to add a Re-attach column in the Media Library (wp-admin/upload.php), that may be of interest:

Small Extension for the Media-Library
[...] images can be easily reused. A link will be created so you can access the image directly and there is no need to upload the image again to your new post. Further information can be found in this post.
Answer: Saying that images are "attached" to a post has always struck me as misleading. "Attached" implies to me that the images would be associated with a post in some manipulable way. That is the problem. That is not always the case.
Some (many) images are hard coded into the post body. This is what you get when you click the media insert buttons. True, there is a mark in the database that associates the image with the post, but that is just accounting (unless you are using galleries). The HTML for the image is embedded into the post body. While manipulating the database entry may break some things, it does not cause the image to move from post to post. To move those you would need to regex the image out of the post body, find its ID, insert the HTML into another post, and then alter the post_parent of the for the image in the $wpdb->posts table. This is complicated by the fact that there is sometimes an anchor tag or shortcode markup-- for example, a [caption]--, or both, around the images.
The thumbnail image is "attached" in the way you would expect (I would expect)-- by an entry in the $wpdb->postmeta table under _thumbnail_id. You can simply edit the database to move those images.
Then there is the gallery... Gallery images should probably be movable by altering the post_parent for the images (untested).
If your problem involves the first case, I don't think there is an easy way to do this, and you better be very good with regex or find a library that will parse your content effectively. The other two cases should be fairly straightforward. You'd just need to Loop though the posts, get the attachments and the thumbnail, and reassign them. I would run that about a 100 times on dummy data before committing it to production though.


What do I need to do before deleting a domain name?

Question: I've owned a domain name including webhosting for a couple of years.
No I don't need the domain anymore. Is there something I should do before deleting the account that includes the domain name, email and webhosting?
(I'm asking because I'm worried that a new owner of that domain name could harm me in some way, e.g. by using the domain name and email)
Comment: If the domain was used to send and receive emails, and not a 3rd party email address then there is nothing you can do, new owners will be able to receive any emails using catch-all addresses. Your only option is not to delete the domain if you don't want anyone else using it.
Comment: @SimonHayter Or at least shutdown HTTP, SMTP, et al, and wait a while (a year or two) to be sure that there is no traffic or value to the domain name.
Answer: Protect your accounts
Change the email address for sites where you have an account with an email address under this domain. (If you don't have a list with sites you've an account on, start one now!)
Preserve your content
Archive your (important) pages in the Wayback Machine if they haven't every page already, or if they are outdated. See how.
Provide your content as download if it's user-generated (the polite thing to do) or if you care about it and don't want it to get lost. You could license it, for example, under CC BY-SA, which would allow others to host/edit it, as long as they allow others to do the same.
Inform humans and bots
Inform your users that the site will go down, and that they won't be able to contact you under this domain anymore. Either give them your new contact details, or suggest that they should delete yours from their contact books.
Inform other websites that have links to your domain (or list your email address etc.) that everything will go down. In case you offer your content under a free/libre license, they could decide to host the linked content themselves now.
Send HTTP status code 410 after deleting your site (except the backup for download). This informs bots that your site won't come back, so ideally wait some time until most bots visited your site again.
If you can afford to wait longer:

Check your logs for referers (possible sites to inform).
Check incoming mail (possible accounts to change or persons to inform).
After some time, stop your email server, and wait as long as you can. Incoming mails will bounce and the senders will hopefully stop sending emails after some time.

Now shut everything down, cancel your domain and hosting account, and regret it later ;-)
Answer: I would end the web hosting of your www.mysite.com but I would keep access to your email and not give up your actual site name. You may wish to use robots.txt tags to disallow all access.
If you are selling your domain to a new owner you can sign a legal agreement regarding email use, etc. But if you simply "do not need" the domain and it contains your brand name or related products I would follow a careful process as described above.
If unclear about the robots.txt: https://support.google.com/webmasters/answer/6062608?hl=en
Also: I would run a check on Google search (in the address bar type) with site:mysite.com and see what is indexed.
Just a parting note: IF your site is more than 10 years old and had good content (original content that can be related to your present work) I would keep it up for outbound link value.


How do I print contents of at jobs?

Question: I have a Debian box with some jobs scheduled using at. I know I can list the jobs with their times using atq, but is there any way to print out their contents, apart from peeking into /var/spool/cron/atjobs?
Answer: at -c jobnumber will list a single job. If you want to see all of them, you might create a script like
#!/bin/bash
MAXJOB=$(atq | head -n1 | awk '{ print $1; }')
for each in $(seq 1 $MAXJOB); do echo "JOB $each"; at -c $each; done

Probably there's a shorter way to do that, I just popped that out of my head :)
Comment: `at -c $(atq | cut -f 1)` or `for each in $(atq | cut -f 1)` will avoid "Cannot find jobid" errors. (Also, Bash has `for ((each=1; each<=MAXJOB; each++))` so no need for `seq`. If you're concerned with portability, then `#!/bin/sh`.)
Comment: don't forget good old `awk`, `atq | awk '{ system("at -c " $1) }'`
Answer: Building upon previous responses, this lists each job's line from atq showing job number and scheduled time and then just the command to be run, sorted chronologically (rather than job number):
for j in $(atq | sort -k6,6 -k3,3M -k4,4 -k5,5 |cut -f 1); do atq |grep -P "^$j\t" ;at -c "$j" | tail -n 2; done

producing, e.g.
48  Fri Mar 10 15:13:00 2017 a root
/usr/local/bin/a-command

47  Fri Mar 10 15:14:00 2017 a root
/usr/local/bin/another-command

Answer: A much simpler approach:
for j in $(atq | cut -f 1); do at -c "$j"; done

You could also look at each one in less in turn, which might be clearer:
for j in $(atq | cut -f 1); do at -c "$j" | less; done

Answer: I've created command atqc for this ("atq with command"). A bash function. Run this on the bash command line (terminal command). Or put it in the ~/.bashrc file to make it available for later:
atqc () { atq|perl -ne'($q,$j)=/((\d+).*)/;qx(at -c $j)=~/(marcinDEL\w+).\n(.*?)\n\1/s;print"$q $2"'; }

Test it:
atqc

That works for RHEL7 with at -V version 3.1.13.
Ubuntu 16.04 with at -V version 3.1.18 has a slightly different output format in at -c N, so on my Ubuntu server this works:
atqc(){ atq|perl -nE'($q,$j)=/((\d+).*)/;qx(at -c $j)=~/\n}\n(.*?)\s*$/s;say"$q: $1"';}

Answer: Here is an alternative approach, similar to the others in this thread but using awk more:
atq | awk '{ print "at -c " $1 }' | bash

To do a "dry run" and see what would be executed, simply remove the "| bash" part from the end.
Answer: I wanted to have my at jobs listed by execution date plus their corresponding command line. Swap the ## at line get_at_line if you prefer the output separated by blanks instead of columns.
me@PC3540:~$ which atl
/home/me/bin/atl
me@PC3540:~$ cat /home/me/bin/atl

#!/bin/bash
PFIX=A00000
get_at_line () {
for i in $(at -l | cut -f1 )
do
 ATLINE=$(at -l | grep ^$i)
 ATSTATUS=$(echo $ATLINE | tr -s " " | cut -f7 -d" ")
 ATTIME=$(echo $ATLINE | cut -f2- | cut -f1-6 -d" ")
 ATISO=$(date -d "$ATTIME" +%Y-%m-%d' '%R)
 ATCMD=$(at -c $i | sed -n -e '/}/,$p' | grep -v -e '}' )
 HEX=$(printf '%x\n' $i)
 VAL=$(printf "%X\n" $((0x$PFIX+0x$HEX)))
 VAL=${VAL,,}
 echo Job: $(printf "%02d\n" $i) $VAL At: $ATISO $ATSTATUS: $ATCMD
done
}
if $(which at > /dev/null)
then
 if [ ! -z "$(at -l)" ]
 then
  get_at_line | sort -k5 -k6 | column -t -s" " -n
  ##get_at_line | sort -k5 -k6
 else
  echo -e "\n.. no at jobs found for user $USER\n"
 fi
else
 echo -e "\n.. service at not installed \n"
fi

How do I print contents of at jobs?


How can I teleport back to my house or even get close to it

Question: I was wondering off to find a wolf, and I got lost. I flew in the air to look for my BIG house and I can't find it. Now, I am totally confused and worried and I don't want to rebuild because it is AWESOME and I used a map, looked it up, and tried everything. So can you please help me? I even tried to teleport but it wouldn't work. I also live by a lake.
Comment: Welcome to Arqade, user210995! Sorry, but we can not possibly know where your house is, especially when we have nothing to go off of, like pictures, but even then it is impossible to know what direction it is in. Your best bet would to be to make a map and try to find it on the map.
Answer: Did you set a bed?  If so, dying will take you to that bed.
You said you tried using a map.  Did you zoom out that map fully to zoom step 4?  If not, it's worth a try.  A zoom step 0 map covers 128 X 128 blocks, a zoom step 4 map covers 2048 X 2048 blocks.
If these don't work, my recommendation is MCEdit.  MCEdit is an external program which can open and search world files.

Open MCEdit
Select your world in the left menu
Click Edit button
On the right will be a large graphic output.  At the top of it is 3 buttons labeled 2D, Over, and Cam.  Click the Over button.
You will now have a 2 dimensional over view of your world.  Look for evidence of your build.  Move the mouse over this build.  At the bottom of your screen, you will have coordinates.

Here is an image of the program with the Over button and the coordinates circled:

Click the image to enlarge.  If you look close, my mouse is over what looks like gardens and trails.  Evidence of a build or village and the coordinates are (-260, 0, 320).
Answer: Is your house near your world spawn? If it is you can just use a compass to get u closer to your house, this will make searching much easier. If you don't find your house and have to build a new one, then when you venture out to explore place a block in the general direction of your house every 10 blocks. This block should preferably be a torch or some other block that emits light so you can follow the trail home at night.
Comment: What platform are you playing on?
Answer: If you know how to use the coordinates displayed on the F3 Debug Screen you can just hit F3 + F2, that will open the debug screen and screenshot your coordinates.
After that you can just navigate your way back, that's what I always do.
Screenshots are saved in */.minecraft/screenshots.


Using Fitness Trackers In Kickstarter Campaign

Question: I'm working on an app for iPhone that uses fitness tracker data. For my stretch goals I'm offering additional device support. Can I use a photo from the device company's news resource website?
News Resource Example
Example of my Stretch Goal
Comment: Can you be more specific and explain what your legal question is? Consider making so a user does not need to click through the links to understand what you are asking.
Answer: You need to check the terms and conditions under which said images were publicized. Content on the primary website are usually "all rights reserved", so reusing them is not allowed.
But product releases are usually accompanied by "press kits" which include images licensed under more lax conditions so media outlet can use them to report about the product. But you still need to read those conditions to find out if they also allow your use-case.
When in doubt, ask the copyright holder of the images.


Toggling the centre dot

Question: I draw a circle, and in the middle of the circle is a dot. This is the centre dot.
I would like to use the line tool to draw a line from the centre. When my cursor is above the centre dot, the Line tool changes automatically into a Move tool. Instead of drawing a line, when I click and drag, it moves the circle.
In the Attributes panel there is an option to turn the centre dot on and off. This has no effect on anything. The dot does not disappear, from circle objects, from line objects, from polygons. It is broken.
I have reset my preferences. I have installed the latest version (at time of writing this is 26.5). My current workaround is to lock the object, then draw the line. I'm suppressing the urge to rant here, but many things in Illustrator that were once very trivial seem to be extremely convoluted. Am I missing an option? How do I toggle that dot on and off?
Answer: Deselect the circle object and the line should draw

Toggling the centre dot


Why is my Linux ICA client unable to use the "CTRL" key?

Question: I have the Citrix ICA/receiver client installed on on both my windows an Linux workstations. On my Windows workstation I can use common keyboard shortcuts like CTRL-A, CTRL-C, CTRL-Z etc. On the Linux workstation no CTRL shortcuts work, but ALT shortcuts for menus do. How do I get CTRL to work in the Linux receiver?
Answer: OK, this is solved. It turns out to be an issue with the Gnome mouse settings (System->Preferences->Mouse). If you have selected "Show position of pointer when the Control key is pressed" then it won't pass Ctrl key presses to Citrix. This doesn't affect any of my other applications, including RDP clients, so I'm not sure why this is an issue for Citrix
Comment: Thanks for the info! I've been pulling my hair out trying to do the simplest tasks on my servers at work, now I'm back in business.I've run into issues with "show the pointer" before and now I recall why I always leave it disabled.
Comment: Doesn't work for me unfortunately. I'm using Ubuntu 13.10 and the latest version of the Citrix Receiver application. (USB-Keyboard / German Layout)
Answer: Not sure what happens in your case, because I also use Citrix on Linux and all Ctrl keys work. One thing I know is that Ctrl-F2 sends the next key-stroke to the Linux host. So for instance if you use Gnome, you can minimize the Citrix window by typing Ctrl-F2 followed by Alt-F9 (which is the shortcut for minimizing windows in Linux).
Comment: Thank you for your response. Somehow that triggered in my mind to to check the mouse settings. See my answer for details.
Answer: I have similar problem with Citrix ICA Client under Ubuntu 12.04 and Win7 as a remote system. But Mark's workaround didn't help to me.
I've solved this by changing ~/.ICAClient/wfclient.ini
Replace:
;KeyboardLayout = (User Profile)

By:
KeyboardLayout = US-International

I suppose that ICA client inadequately choose system keyboard layout, because I have bilingual system locale (EN+RU).
Comment: Combined with [this answer](http://askubuntu.com/a/190636/107898), this allowed me to send Ctrl+Alt+Delete as well
Answer: I get into this condition from time to time, this is likely triggered by something I type that I don't know exactly what it is.
When I get into this condition, a "shift + scape" usually fixes the problem.


Starting of direct current Motor

Question: what happens if starting arm of starter does not return to "OFF" position after a temporary supply failure?
Comment: It starts when the supply comes back on ...
Comment: @SolarMike are you serious
Comment: The dc starter adds resistance to armature winding to limit starting current.  As Mike says, motor starts with current depending on position of starting arm.
Comment: @StainlessSteelRat that is the point if position of starting arm is stuck to its position after a temporary power supply failure what would happen. Resistance offered by starter would be zero, ... Right?
Comment: Yes.  The purpose of the dc starter is to limit starting current by inserting a resistance.  If starter was locked in on position, motor would start as a shunt (compound, etc) motor.
Answer: Schematic Diagram of a Manual Face Plate Starter is shown for a DC Shunt Motor.
From Quora: If the field from a DC motor is removed, what would happen?  Original Source: Electrical Machines And Power Systems by Wildi.

As arm moves from M to N, full voltage is supplied to field winding and electromagnet.  Field current $I_x$ flows.  Drawing is a little misleading, since as long as any contact is engaged, full source voltage is applied to field winding.
But starting current $I$ ($I_a$ - armature current), is limited by series connection of $R_1$, $R_2$, $R_3$ and $R_4$ into the armature winding.  Contact arm conducts.  As the arm moves through the contacts, each resistor is removed from the armature circuit until the full voltage is applied to the armature.  Armature starting current is governed by:
$$ I_a = \frac {E_S - E_o}{R_a + R_1 + R_2 + R_3 + R_4}$$
At locked-rotor (LR), the Counter EMF $E_o = 0$.  No rotation, means no induced EMF (Electromotive Force).
$$ I_{a_{LR}} = \frac {E_S}{R_a + R_1 + R_2 + R_3 + R_4}$$
The resistors limit the LR current to 1.5 to 2 times rated current.
Factor in Counter EMF $E_o \ne 0$ as rotor starts to move and the removal of resistors as contact arm moves clockwise means armature current builds up in a controlled manner to rated full-load current (if driving full-load).
$$ I_a = \frac {E_S - E_o}{R_a}$$
When the steel contact arm gets to the electromagnet, it is held in place until field loses power, for example when the power is disconnected.  Then spring 3 should bring it back to contact M.
Answer time: If the arm does not return to starting position, then the armature current that flows is governed by where the arm is.  The Starter is mechanical and things fail.
If it stays on the last position, then LR current is:
$$ I_{a_{LR}} = \frac {E_S}{R_a}$$
This could be 5 to 8 times normal full-load current.  The resistance of the armature winding $R_a$ is small, which could (from Wildi):

a. Burning out the armature;

b. Damaging the commutator and brushes, due to heavy sparking;

c. Overloading the feeder;

d. Snapping off the shaft due to mechanical shock;

e. Damaging the driven equipment because of the sudden mechanical hammerblow.

Now, if it stops at any other contact, say between $R_3$ and $R_4$, then resistor $R_4$ will limit some of the LR current.
$$ I_{a_{LR}} = \frac {E_S}{R_a + R_4}$$
There still may be damage, but less than with no resistance.

Starting of direct current Motor


Can using a heavy duty extension cord for a space heater cause a receptacle to melt?

Question: I have an outlet that burned up pretty badly - it is on a recently run 20 amp circuit. I had a space heater plugged into a heavy duty extension cord running from this outlet. From what I have read it seems,like this is often caused by loose wiring but I don't believe that is the case here. I have cut back the hard wiring to a point where the wire is clean and free of any burning and want to replace the outlet but am really concerned with what may have caused the problem in the first place. I feel like the outlet may have just been overloaded is that likely?
Comment: Was the old connection via a)  J-hook on the wire onto the screw terminals, or b) backstabs? Can you tell what size the wire in the wall is?  Did the extension cord end also burn up?
Comment: The hard wiring is 12/2 and run 6 mos ago. It is hooked on the terminal screws not back stabbed. The receptacle itself melted - there were no flames but I smelled burning and started investigating where it was coming from and it was glowing red on the side if the receptacle inside the box the receptacle itself is melted and the wires hard wiring was charred at the point where it was tied into the receptacle - it was hot enough that it melted the box. The extension cord appears to be free of any charting or melting
Comment: Please clarify: What parts melted?  The heater's cord?  The receptacle?
 Wire jacketing behind the receptacle?  When you say "burned up" do you mean charred?  Smoked?  Did you actually see flames?  What else did you have connected to the outlet?  What gauge are the wires to and from the outlet?
Comment: 20 amp circuit - but what was the outlet rated to support?
Answer: From the comments you seemed to just have a weirdo defective receptacle.  Don't buy the contractor pack 2 for .99 cents.  Buy a good 20A receptacle for a few bucks and put it all back together.  12 ga wire will handle 15 amps which is all a space heater should ever pull.  Fire it up and monitor it for a bit.  If anything is questionable, I would start to look at the space heater itself but then again your breaker should trip before anything gets out of hand.
Comment: If this was my house, I'd be a tiny bit concerned that the breaker isn't working as designed. A simple test would be to run the space heater and another high draw device (kettle, etc) and make sure that it trips the breaker. Your panel isn't Zinsco or FPE, is it?
Comment: Thanks for your input - obviously when its concerning electric you can't be too careful and I really needed that second opinion. Thanks for your help!
Comment: In General space heater circuits are rated at 100% of their rated load, but if they are in a particularly cold area they may be running more than 3 hours. That would move it to a continuous duty demand and you need to add 25% to get the proper circuit size. Example a 1500W heater divided by 120V =  12.5 amps or a 15A circuit is fine, if you have to 25% for continuous duty, thats 15.62 A. So you will need to move to a 20A circuit and devices, or set your heater to a lower range if possible. Use your best judgement.
Comment: The OP stated that he is connected to a 20A circuit so continuous duty for a 1500W space heater should be fine.


How to explain a mermaid's tail morphing into legs and vice versa?

Question: I know a tadpole can do this transformation, given enough time, so what about mermaids?
Comment: Do you mean at will, or as it grows like a tadpole / frog?
Comment: What about the tail having "pockets" for the legs?
Comment: @colmde: preferably but not due to unfortunate causes such as illness or statistics for example encountering a chicken and live to croak out loud
Comment: Magic.  Always magic
Comment: What would Ron Howard do? http://www.imdb.com/title/tt0088161/
Comment: and how about they have both legs and a tail and will drop the tail like the lizards when disguising itself on dry land and grow back when underwater...
Answer: You either invoke magic, or they are really 'legs' that can 'velcro' together.  It takes months for a small frog to change.  On top of that frogs' tails don't split into legs, legs grow out from the base of the tail and the tail shrinks back into the body.
A similar process for mermaids I would think would realistically take years.
Adding: Merfolk could be amphibious, so that the young are born with tails, 'teenagers' are growing legs and adults have full legs to leave the water with.
Comment: For some reason, I never realized that mermaid tails are just like human tails, that is, not legs. Now I'm imagining mermaids with little fin-feet, and I gotta say, it's not nearly as attractive.
Answer: Give them legs. They could be separate from birth and just covered with a swimsuit. Or they could be joined at birth and separate during puberty. These follow somewhat from some...
Real life precedents
Sirenomelia
Tiffany Yorks, Shiloh Pepin, and Milagros Cerron were born with a rare condition called sirenomelia or "mermaid syndrome", where the legs did not separate in the womb. Though Shiloh could not undergo separation surgery because her legs' blood vessels were too tangled, Tiffany and Milagros had their legs successfully separated. Both needed extensive rehabilitation to walk, and Tiffany's continuing mobility issues echo the admonition of the Sea Witch in H. C. Andersen's story that "at every step you take it will feel as if you were treading upon sharp knives."
Monofin
A monofin is a paddle that clips to a swimmer's feet, giving more surface area for a dolphin kick. This leads to improved performance in swimming and free diving. Cloth covers for the legs and monofin allow professional swimmers to perform as mermaids in public. These covers are also sold commercially by firms such as Mermagica; others are custom-made.
Sea Gypsies
The Moken people and Sama people are two Austronesian ethnicities living seaborne nomadic lifestyles. These "Sea Gypsies" are known for seeing underwater and holding their breath for several minutes.
Famous swimmers
Michael Phelps won a dozen Olympic golden medals for swimming in 2008 and 2012. In his autobiography No Limits, he attributes this to his long, thin torso, long arms, short legs, and large feet connected to hypermobile ankles. Pauli Poisuo of Cracked called him "basically a seal." Similarly, Icelandic fisherman Gudlaugur Fridthorsson swam for six hours in freezing water in 1984. After his full recovery, it was discovered that his body fat resembled that of a seal more than a human.
Suggestions
Francine DeGrood Taylor's answer that they are descended from humans who adapted to a semiaquatic lifestyle sounds like it's on the right track. But there are two ways this could go, even without any sort of magic.
One way leaning toward hard science is to make merpeople just a human ethnicity. This works well for "selkies," who can change between human and seal-like forms by putting on a sealskin wetsuit. Ethnic merpeople may resemble Sea Gypsies, with physiologic traits resembling those of Phelps and Gudlaugur, and wearing bamboo-tech monofins with a covering to hold the legs together and reduce drag.
Another more extreme adaptation might be to have babies born with webbed legs, similar to sirenomelia. The children prefer to move through water, not straying far from the beach or the river, because moving on land requires placing one arm and the heel forward and then pulling the butt up to meet them. (Shiloh demonstrates this technique in one of the TV documentaries about her.) Around puberty, hormonal changes cause the webbing to retract, separating into legs over the course of the next few years. Puberty would be a pain, as adolescents would need to learn how to walk from scratch.
Answer: Add a few more joints to the legs so they can bend right when acting as a tail, then reintroduce our vestigial tail as a long thin muscled membrane which can be wrapped repeatedly around the waist and chest when in biped mode, or can encircle the legs and spread out at the feet when in aquatic mode.
Serious genetic engineering required, but it might work.
Also, if you make the membranous tail (or tails) pretty, they might serve as garments when wrapped around the torso and groin, explaining why mer-folk are usually depicted as topless when shown in fish form.
Answer: What if the mermaids actually had legs (although legs that were jointed a bit differently) and those legs provided the structural support for the flesh cover of the tail?  Perhaps their evolutionary trail led in the opposite direction from humanity's; they started out as bipedal (or tripedal?) beings and moved into the water.  In order to move more efficiently, they developed fleshy extrusions that grew longer, long enough to encompass their legs.  So, in order for the legs to emerge, the skin of their tails must be shredded.  This would make it very painful (hence the similarity to the HCA version of the mermaid, whose mobility caused her terrible, cutting pain).
Or possibly the tail skin requires immersion in order to stay alive.  If the skin is dried out, it dies and turns brittle and is "shed" so that the legs separate and the mer-person can walk.  Once they return to the water for long enough, their bodies start producing a mucus-like substance that grows down to cover the legs (and perhaps fingers as well, giving them webbing).  The mucus could cover the entire body, providing insulation and protection from the inevitable battering of an environment that is often in violent motion.


Open data sets about software development: code quality, defect rate, programming languages?

Question: I'm looking for open freely available data sets related to software development quality: code quality, defect rates, comparison across programming languages. Where/how can I find such data sets?
Answer: Here are a few sources to take a look through:

Most comprehensive and closest to what I think you're looking for is a project by the acronym of PROMISE (PRedictOr Models In Software Engineering). Go to http://promisedata.googlecode.com/svn/trunk/defect/ to go straight to their data which is organized by code base and into CSVs. For example, tomcat.csv. It looks like the project also has a number of tools to help analyze and create models from the data.
Eclipse Bug Data! is, as it sounds, a project to mine bug and version datas from the Eclipse project.
NASA also publishes "cleaned versions of publicly available NASA MDP software defects data sets" over at http://nasa-softwaredefectdatasets.wikispaces.com/

EDIT: there are also a number of academic papers on this topic that you might want to skim to see if they reference specific data sets or sources.
Answer: Note: This answer only covers a particular aspect of code quality.
OpenHub (ex Ohloh) contains 666,192 projects and mentions for each one:

The number of comment lines
The total number of lines
The programming language used (or proportions if several used)

So, you can use that data to compute the comment/code ratio for many programming languages.
License: CC-BY
Answer: Some of the projects listed under the data sets section of dspinelli's awesome list for mining software repositories (MSR) stuff might be useful.  Some examples (additional information found on the GitHub list and through the links themselves):

CoREBench: Realisitic, complex regression errors
Bug Prediction dataset
Unified Bug Dataset
Ultimate Debian Database
RepoReapers
Maven Metrics


BGP Dual-As support, any RFC?

Question: Generally most of routers like cisco and junos allow a router to have dual-As to be configured via a "local-as" command which overrides the global as-number configured in "router bgp ". Also local-as prepending may or may not happen based on configurations; for example "no-prepend" in cisco.
Now my question is, is there any RFC which which standardises this Dual-As support?? Which provides guidelines on whether or not to prepend the "local-as" to As-Path attributes in the Bgp updates ?
Answer: no, there is not an RFC detailing this feature at this time.

BGP Dual-As support, any RFC?


Lufthansa economic flex refund policy

Question: I'm looking into buying a lufthansa economic flex ticket so if something happens and I am forced to cancel my trip under any circumstance, then I can get my money back (I'd cancel the entire trip, outbound and inbound). My question is if I can just cancel my ticket and get my money back ? (I assume I'd have to pay some fee).
Comment: have you read the guidance on Lufthansa's site? I'm not sure we could give better info than that.
Comment: I tried reading it but it might be due to my lack of focus at the moment but it was quite unclear.
Comment: Is there something specific about the T&C that you don't understand?
Comment: Yes, if I get my money back from cancelling my economic flex ticket or not.
Answer: According to Lufthansa's website for "Baggage & Other Fees", the "Fare overview Economy Class" section states that a Flex II ticket refund is free and has no fee.

Lufthansa economic flex refund policy


How I can block Psiphon?

Question: I have a Sonicwall firewall. I want to block the Psiphon mobile and PC applications.
I denied access on these ports: 51,5242,4244,5243,9785,1701,47,443,500,4500,1080
Most VPNs are closed but the Psiphon app still works; how I can block it?
Comment: Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
Comment: I never had any problems with connection speeds or buffers with Psiphon. Maybe it should be tested again this year as it has improved a lot. Note: the [Psiphon](https://psiphondownload.com/) is blocking for only devices in which we install the self-sign certificate.
Answer: I'm quoting what is posted on the Psiphon page:

You can only establish connections via Psiphon by using the following ports:
  53, 80, 443, 554, 1935, 7070, 8000, 8001,
  6971-6999.

If you block these ports, you will also be blocking a lot of services in your network.
You need to do Deep Packet Inspection if you want your really block Psiphon.

https://psiphon.ca/es/faq.html
Comment: i tried to block all this port the web page failed to access internet but psiphon connected successfully :D
Answer: If you want to block this application, you must block all VPNs which are not yours.
Psiphon can mount proxy HTTP/SOCKS via tunnels. All the traffic of this application will bypass the port TCP 80 by default. So you must to have a firewall capable to inspect your packets to see which packets are real HTTP packets and HTTP proxy packets.
You can't block this application only with port numbers.
Answer: I work with a High School and some of the students are using Psiphon to get around our web filter. So I believe we were having a similar issue. We found that A third party managed firewall and web filter filled our needs better than closing so many ports that have important services running on them. We used iboss for our web filter and firewall and we were able to curtail the problem with Psiphon.
Comment: thank you for your replying , can you explain more about iboss
Comment: I will post a link to their site but I dont want to violate forum rules  so I.ll just say they are a paid for firewall, web and spam filter. You can find out more information and contact them through this site [link](http://www.iboss.com/)
Answer: To be Honest, with my experience using and testing Psiphon, As long as the user has any kind of internet, no matter the block (even if though), Psiphon seems to manage it's way in anyway. It's lightweight setup make you able to use on a flashdrive (so it doesn't need to be installed on the PC at all, just need to plug in thumbdrive) and versatility makes it very hard to block, even temporally. not to mention that if it even get a ping from any open sever, it automatically updates itself, makes a backup copy, and gets new sever list. The reason why it's like this is because, it's designed to allow you access even in a another country where blocks are really strict... Basically, you're trying to march though the jungle but, up against an army that specializes in guerrilla warfare...
Answer: If you want to block this application, you will must to block all VPN which are not yours. You may check this detailed guide on Psiphon here or just follow the steps below to unblock the app:--

Enable DPI-SSL Client Inspection by going to DPI-SSL | Client SSL and selecting Enable SSL Client Inspection. Ensure that IPS, GAV, Spyware, and Application Firewall are selected.
Enable all Psiphon application signatures by going to Firewall | App Control Advanced. Select the category PROXY-ACCESS and application Psiphon. Configure the application to be blocked and logged.
Also block Encrypted Key Exchange TCP Random Traffic (SID 5).
Enable blocking of SSH app signature (SID 10097) "SSH -- Client Request Outbound", (or make access rule to block outbound TCP/22 SSH Service from LAN->WAN).
Answer: Ok folks, so here it is. After fighting this monster for about 9 months, I finally figured out how to stop PSiphon from running on my computers. PSiphon is a standalone program, because it does not install itself to the computer, there are no hash's or certificates to manipulate. I finally google'd how to stop .exe files from running and low and behold there it was. You have to set up a GPO to prevent psiphon3.exe from running. You will create this rule under the user configuration\administrative templates\system\Don't run specified windows application. From here you can figure out the rest. Now I have tried to run it on the computer, from the website and from a drive stick and they all failed to run. Can't wait for morning to get here so I can implement this on the computers at work. Hope this helps.
Comment: You should accept your answer so that the question doesn't keep popping up forever, looking for an answer.
Comment: Couldn't they just rename the .exe as a workaround?
Answer: I have managed to do this by blocking the file path of the temp exe it creates when connecting. This removes the ability to rename the original exe and it works again (or having duplicates in downloads, i.e. "Psiphon3 (1).exe").
Use User or Computer policy,
Policies/Windows Settings/Security Settings/Software Restriction Polices/Additional Rules
New Path Rule -> %userprofile%\AppData\Local\Temp\psiphon-tunnel-core.exe

How I can block Psiphon?


The use of second authorship paper for graduate admission

Question: During my undergraduate, I have a publication, however I am listed as the second author. I know it is not as ideal as being listed as first author, but for graduate admission, will it still play a role?
Comment: Congratulations on the early paper, by the way
Comment: What field is your paper in? If it's math or some branches of CS, "second author" _only_ means "second author in alphabetcal order".
Answer: No-one would expect an undergraduate to publish papers so the fact that you have been involved in publishable research is a merit. One of the goals of a Phd education is to learn to write good research papers so, again, no-one would expect that from your from the start. I would suggest that you try to describe your contribution to the paper so that your authorship can be valued from the perspective of that contribution. Being able to understand the skills and experience of a student, provided it is good, is of value in a selection process.
Comment: _No-one would expect an undergraduate to publish papers_ — This _really_ depends on the field and the target department.
Comment: @JeffE  While there are likely many good departments who admit several published first authors, I find it doubtful, though, that this is "expected" of applicants in almost any department. Expected is a very strong word, to me, it means that not having a pub pretty much eliminates one from consideration in all but exceptional circumstances. Publications are not "expected" in math, bio, psych, sociology etc even at the most elite schools in the USA [at least by my definition]. Can you share what departments would "expect" this?
Comment: In practice, **most** new PhD students in machine learning at top-5 departments have publications when they apply.  Same for a significant fraction of top departments—especially smaller departments—in other subfields of computer science; theoretical computer science at Princeton is a good example.  As far as I'm concerned, that makes publication a _de facto_ expectation for admission for those departments in those subfields.
Comment: @JeffE ok yes, if we are going as specific as subfields of research within a department, I bet you are right. There are likely a few others too.
Answer: It will absolutely still play a role. What graduate schools are looking for in terms of publications, undergraduate research conferences, etc. is not that you already have an established body of first author publications (that's the point of grad school) but that you have some experience and aptitude for research.
A second-author publication establishes that.
This is especially true in some fields like medicine, public health, etc. where the results of a large study might have many authors, and no matter how much you contributed as an undergrad, the odds of you meriting first or last authorship is slim. However, regardless of your field, there are some things you should also consider doing:

As @PeterJansson suggested, make sure you can describe what it is you contributed to the paper. You might not have room for this on your CV, but in application essays and in interviews, this will be important. If it's the only paper on your CV (which is likely), you're going to have to talk about it. It won't be held against you if you're the 2nd author, but it likely won't look good if you can't communicate what the paper was about or how you helped.
Consider seeing if there are ancillary questions in the research (how sensitive our our results to X? What about Y?) that might make good projects you could take the lead on and get a conference presentation or short paper out of.
Similarly, look out for opportunities to present undergraduate work at your institution, and apply to those. Even if you're not the first author on the publication, it's often possible to present on your part of the work in the context of the larger whole.
Comment: You will almost certainly be asked to talk about it, possibly in some detail depending on the research parts of you undergrad course.  It's a really good starting point, so read over the material including background again to be sure you can explain the whole thing as well as just your role in it.


tons of problem, Fill_in_dev failed, black screen

Question: I'm new to this (linux world)
My friends recommended me to install ubuntu to start because it is basic and popular. lol.
I have this problem;
Disabling IRQ #10
Disabling IRQ #10
10 years later..
[drm:drm_pci_agp_init] Error. Cannot initialize the agpgart module.
DRM: Fill_in_dev failed.

Then black screen.
Packard Bell Easynote TS11HR
Intel Core i5-2410M
4GB DDR3
Nvidia GT520M 512mb ram
HDD 640gb but i have windows too
Ubuntu version 13.10 (12.04 kernel panic error, mount root btw, another story)
I install this SO with noapi, nolapi, acpi=off and nomodereset, because it was the only way. black screen when select live and install, bootable options.
I try added those parameters in sudo nano etc/default/grub, but no results.
Can anyone help me? Or tell how can uninstall without affecting windows.
Sorry for bad english, i speak spanish.
Answer: It seems that your OS (Ubuntu 13.10) has been badly modified and resulted in kernel panic. When i experience the same thing as yours, I reinstall it again using my liveUSB and my extracted .iso in it. Did you install Ubuntu via wubi? else you can just delete it into the Windows directory.