JDK 8 Memory Layout and garbage collection

Question: From what I know, starting with JDK 8 the PermGen will be a past page in java's history. Everything nice and merry... but what will the new Memory Layout look like? Will this affect GC on the new platform?
Comment: Note that "Java Memory Model" has [a *very specific meaning*](http://stackoverflow.com/tags/java-memory-model/info) which is not really related to what you're asking. Yes, the name is confusingly similar to what you're asking.
Answer: PermGen is replaced with Metaspace in Oracle/Sun JDK8, which is very similar. The main difference is that Metaspace can expand at runtime.
Comment: @user503413 Based on the link I provided: "By default class metadata allocation is limited by the amount of available native memory (capacity will of course depend if you use a 32-bit JVM vs. 64-bit along with OS virtual memory availability)." It can be also limited with `MaxMetaspaceSize` parameter
Comment: OK...so how much can it grow? is it bound by just the maximum amount of memory a java process can have?
Answer: This is when permGen is there

After Metaspace is introduced

Definitely, there is lot of improvement in GC in Java 8.
You can check this stackoverflow post
In Metaspace, multiple mapped virtual memory spaces are allocated for metadata and allocation ( in chunks) is per class loader depending on the type of classloader and its liveness .
Chunks are returned to free chunks list and also virtual memory spaces returned when emptied.
Advantage of GC would be

During full collection, metadata to metadata pointers are not scanned
A lot of complex code (particularly for CMS) for metadata scanning was removed.
Metaspace contains few pointers into the Java heap.
No compaction costs for metadata
Reduces root scanning (no scanning of VM dictionary of loaded classes and other internal hashtables).
Comment: Can you please clarify what are the 'VM metadata' exactly?
Also what are so-called 'Internal Hotspot types' and how they have been affected?


finite flat commutative group schemes arising from Abelian varieties

Question: How are the finite flat group schemes $\mathcal{A}[\ell^n]$ arising from an Abelian scheme $\mathcal{A}/S$ singled out among other finite flat commutative group schemes of exponent $\ell^n$?
Comment: @Scott: a group scheme killed by $\ell$ won't be the $\ell$-torsion in an abelian variety if it has order $\ell^n$ with $n$ odd. And there are other obstructions other than this: e.g. a group scheme of order $\ell^2$ and killed by $\ell$ won't be the $\ell$-torsion in an elliptic curve if it's not self-dual (by the Weil pairing); but even this isn't enough; e.g. $\alpha_\ell\times\alpha_\ell$ isn't the $\ell$-torsion in a characteristic $\ell$ elliptic curve either, because of a formal group argument. My gut feeling is that there is unlikely to be a simple neat criterion.
Comment: If there were a simple criterion which told you precisely when a 2-dimensional mod $\ell$ Galois representation of the absolute Galois group of the rationals were the $\ell$-torsion in an elliptic curve, then we would have known lots of new cases of Serre's conjecture the moment Taniyama-Shimura-Weil was proved---and this didn't happen, so this is more evidence that the question may well not really admit a satisfactory answer.
Comment: By the way, there is also an article by Christian Liedtke, entitle "The p-torsion subgroup scheme of elliptic curves"
http://arxiv.org/abs/0904.1307
in which he studies what kind of twisted forms of $\mathbb Z/p \oplus \mu_p$ can be realized as p-torsion of elliptic curves over fields of characteristic p.
Comment: Do you happen to have an example of a finite flat group scheme of exponent $\ell^n$ that doesn't come from the $\ell^n$-torsion in an abelian variety?
Answer: Is the abelian scheme you consider a fixed one?
If the base is of characteristic $p$, and $l = p$ then the Lie algebra of $A[l]$ is isomorphic to $Lie(A)$, so you get a dimension condition.
For example, $\alpha_p \oplus \alpha_p$ cannot be embedded in an elliptic curve.
There are also more general condition your group scheme $G$ should satisfy.
Assume that $S$ is the spectrum of an Artinian algebra and that
$G$ is $p$-torsion with a trivial bi-nilpotent part.
We have an exact sequence:
$$ 0 \to G^{mult} \to G \to G^{et} \to 0$$
then the orders of $G^{mult}$ and $G^{et}$ must be equal if $G$ is the $p$-torsion of an abelian scheme.
On the other hand, in section (15.4) of the book "Commutative group schemes" of F. Oort, there is the following result:
Every finite flat commutative group scheme is a subgroup scheme of some abelian variety $A$.
Comment: Here is a related result, due to Raynaud : every finite locally free commutative group scheme $G$ over a scheme $S$ can be embedded into a projective abelian scheme, Zariski locally over $S$. This is in Berthelot, Breen, Messing, Théorie de Dieudonné cristalline, th. 3.1.1.
Comment: The statement is at the beginning of section (15.4): Finite subgroups of abelian varieties
Comment: @Holger: could you say where is the statement you quote from Oort's book ?
Comment: Excuse me for not giving the exact reference. Today I am nowhere near the library so I cannot fix it right now, but it's on my list for tomorrow.
Answer: I'm reminded of two papers by Maja Volkov, an erstwhile student of Jean-Marc Fontaine.  They are
MR2148801 (2006a:14027)
Volkov, Maja
A class of $p$-adic Galois representations arising from abelian varieties over $\Bbb Q_p$.
Math. Ann.  331  (2005),  no. 4, 889–923.
MR1837096 (2002d:11067)
Volkov, Maja
Les représentations $l$-adiques associées aux courbes elliptiques sur ${\Bbb Q}_p$.
J. Reine Angew. Math. 535 (2001), 65–101.


How can I remove the default browser favorites?

Question: The default browser on my Galaxy S Vibrant running Froyo has a bunch of favorites pre-loaded -- CNN, Facebook, etc.  The browser tells me they can't be deleted when I try.  How can I delete them?  Is there a folder of them somewhere I can just delete?  I am rooted.
Answer: Doing a full Clear Data on the default browser ("Internet" on the Incredible) worked for me. Just make sure you have your other bookmarks backed up (for example, using an app such as Backup Bookmarks could be used to back them up to SD). The steps should look something like this:
Settings > Applications > Manage Applications > All > Internet > Clear Data
EDIT: As mentioned in the comment below, Bookmarks Manager allows users to delete the default browser favorites/bookmarks. Note that the crossed-out portion of this answer would erase things such as history, entered text, etc. however, apparently not the default bookmarks.
Comment: Unfortunately, after clearing data I actually have *more* undeletable bookmarks than before.
Comment: Very strange... can you delete them using this app? [Bookmarks Manager](https://market.android.com/details?id=com.guenmat.android.bookmarks) (longpress > delete). Not sure why Clear Data generated *more* undeletable bookmarks but it seems like that is a wrong answer. Let me know if this works...
Comment: Bookmarks Manager did it, thanks.  +1.  I assume the browser has some sort of "initial setup" where it restores those bookmarks or something.


no corruption! I need help

Question: I have went from left to right, up to down and my world only has jungle, beach, crimpson, and snowy biomes. I had that world since 2019 and worked so hard on it, i really don't want to make a new world and probably have the same problem. Is it possible to bring those orbs with you into another world, if so please help me.
Answer: Each terraria world will only have one evil, either corruption or crimson. If you want corruption stuff I believe you need to make a new world, but use the same character. In 1.4 there is a way to choose which evil you want.

no corruption! I need help


is there an easier way of doing corners like this?

Question: im doing models of interiors and one of the parts used molding around doors. is there a easy way of doing my corners other than having to get 2 frames and work inwards towards eachother?
Comment: Can you articulate your question a little better please? What do you mean two frames? Also please describe what you mean by working inward toward each other?
Comment: I know what he means. He's using two objects and trying to join them into a door frame. There are many methods to do this, One way is to use a cube scaled to the outer parameters of your frame, and then to subdivide it or loop-cut it to mark out the inner opening, then just delete the faces and bridge the open faces along the inside.
Comment: @maiira in the future crop your images and plese include in the image only information relevant to the question. To make a screen capture within blender, you can press Crl F3 and then choose to save the whole interface as an image or just the active window.
Comment: related: http://blender.stackexchange.com/questions/19709/extrude-along-path-sharp-corners/19717#19717
Answer: Here's a pretty solid workflow if you don't desire to use multiple objects in the creation.
I'm posting the image sequence for now, so I don't mess that part up, then coming back to give the commentary per image.

Shift+A >> Mesh >> Plane.

Tab to enter edit mode.

I to inset the active face the desired amount.

Delete >> Only Faces.

Result of Deleting the face (giving you the major frame profile).

A to select all faces.

E to extrude the desired overall frame thickness.

Ctrl+R >> 2 >> LeftMouseButton >> RightMouseButton

Click on the Face Mode icon/button.

Z >> Select the inner ring of faces (as shown).

With your cursor just outside the outer edge of the frame E >> S >> Move your mouse toward the center of the frame the desired amount >> LeftMouseButton

Click on the Edge Mode icon/button.

Select the Edge Loops at both the Inner Top & Inner Bottom of the frame.

Ctrl+B >> Move your mouse outward the desired amount >> Either type the number of segments & hit Enter OR scroll up on the scroll wheel of your mouse the desired amount & LeftMouseButton.

Hit Tab & you are complete if you desire a 4-Sided frame.

If your desire is to have a 3-Sided frame >> Tab to enter edit mode. >> C >> Select the bottom most horizontal edges of the frame.

Delete >> Only Edges & Faces.

The result is two empty holes that we must repair/fill.

Loop Select the left most hole. >> F to fill.

Loop Select the right most hole. >> F to fill.

Select both Edge Loops again.

S >> Y >> Numpad 0.
Comment: From Steps 18-21 the profile looks wrong because I accidentally did some steps twice on my end trying to put the document together. I fixed this and the steps are good.


Show help text above input and below title of a cck field

Question: Hi I am working with a drupal 7 I have created multiple content types for the site. I want to display the content of the help text of a particular cck field above the input field instead of displaying it below the input field
Answer: you could use template_preprocess_field ( preprocess for theme_field ) to adjust the position of field description/help text.
Cheers
Comment: Doesn't this only affect the view of a node, rather than the form used to create/edit it?
Answer: There's a module for that: Label Help

In normal rendering of Drupal form fields, the field's "description"
  (i.e., its help text) gets placed below the form's input element,
  which is not necessarily the most useful place to place it. On
  textarea form fields that enable multiple input formats, for example,
  the field's help text gets placed below the text format selector and
  tips. This means that website users are unlikely to notice and read
  the help text.
Comment: Hello and welcome. Please avoid link-only answer. The least you should do is to quote relevant part of module's page to show how exactly it answers the question.


can't view static files with nginx + gunicorn on osx

Question: I am trying to setup a django production server on OSX (Mavericks).
This is my nginx server config file:
server {
    listen       80;
    server_name  localhost;
    error_log   /pathtoerrorlog;
    access_log  /pathtoaccesslog;

    # serve static files
    location ~ ^/static/  {
      root    /Users/Hello/assets;
      expires 30d;
    }

    # serve media files ~ ^
    location ~ ^/media/  {
      root    /Users/Hello/assets;
      expires 30d;
    }

    location / {
      proxy_set_header Host $host;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
          proxy_set_header X-Real-IP $remote_addr;
      proxy_pass http://localhost:8000;
    }
  }

This is the nginx.conf config file
user www-data;
worker_processes  4;

error_log   /var/log/nginx/error.log;

events {
    worker_connections  4092;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;
    tcp_nopush      on;
    tcp_nodelay on;

    keepalive_timeout  65;

    types_hash_max_size 2048;
    server_names_hash_bucket_size 64;

    gzip  on;
    gzip_disable "msie6";

    include /etc/nginx/sites-enabled/*;

}

I have created a user called www-data on the system and gave the folllowing access permissions:
sudo chown -R www-data:www-data /usr/local/etc/nginx
sudo chown -R www-data:www-data /etc/nginx
sudo chown -R www-data:www-data /var/log/nginx

I started gunicorn without any errors and so is the case with nginx too.
In a browser, localhost redirects me to the django app but static media is not displayed. This is a sample error (out of all for static content) I get, as I see in nginx error log:
2014/01/25 20:16:23 [error] 35068#0: *68 open()    "/Users/Hello/assets/static/css/base.css" failed (13: Permission denied),
client: 127.0.0.1, server: localhost, request: "GET /static/css/base.css HTTP/1.1", host: "localhost", referrer: "http://localhost/"

I tried changing the permissions of /Users/Hello/assets using sudo chown -R www-data:www-data assets but it didn't help. -R 777 also didn't work.
Please suggest where I am going wrong. Thanks!
Answer: It turns out to be that read permissions have to be granted for all parent directories of /Users/Hello/assets. So, I set read access to all of Users, Hello, assets and not just assets as earlier.
Related articles are :
Nginx 403 forbidden for all files
http://nginxlibrary.com/403-forbidden-error/


Is there any STAC catalog available for Sentinel-2 data on Google Cloud?

Question: We are looking for a fast and optimum way of discovering and downloading Sentinel-2 data from Google Cloud using Python.
We have tried using index data in BigQuery and it works. However, we have also come across Python packages (such as: sat-search https://github.com/sat-utils/sat-search) for searching and downloading publicly available satellite imagery using STAC compliant APIs that we would prefer to use, but we haven't found any STAC catalogs for Sentinel-2 datasets on Google Cloud or any STAC API endpoints for the same. Is anyone aware of any STAC catalogs for datasets on Google Cloud or if there are plans to have them in the near future?
AWS has both: Sentinel-2-L1C and L2A datasets, and has recently released these in COG (Cloud Optimized Geotiff) format which seems to be better suited to large-scale and distributed computing. Does anyone know if similar datasets will be available on Google Cloud as well?
Answer: Here you can find a list of public STAC Catalogs and there is the Google Earth Engine STAC Catalog here.


Can I live view my Nikon D3200 via laptop/ tablet etc?

Question: I am wanting to take self portraits using my Nikon D3200 and was wondering is there a way I can stream the live view through a laptop, tablet or some other screen?
I want to have the screen facing me so I can see what the picture will look like before I capture it so it's not a case of clicking and hoping.
I have an AV out (from camera) to USB lead and also an AV out (from camera) to the yellow and white lead
Hope that makes sense
Thanks
Comment: Here is a relevant question with answers that might be helpful for you as well: http://photo.stackexchange.com/q/36130/9161
Comment: Slightly different model (D3100, the predecessor to the D3200), but the exact same issue and answer. http://photo.stackexchange.com/q/36130/15871
Answer: Assuming you are on Windows you could try out DigiCamControl (I'm not affiliated). They list the Nikon D3200 as partially supported. Live view works, however, you can't use manual focus in live view and can't set the focus area.
Answer: I believe Sofortblid would work with your camera and provide the features you need if you are on mac. (Other answer is windows only.)
http://www.sofortbildapp.com


If the whole point of recursion is to break the problem into multiple smaller problems, what if those problems were solved in parallel?

Question: So I was studying here and I was thinking if the whole point of recursion is to break the problem into multiple smaller problems, what if those problems were solved in parallel? A quick search lead me to links like this where people say it's not worth it because of context switching which makes sense, but what if instead of spawning lots of threads one has a fixed number of threads and stores the state of the recursive calls into a data structure like a stack for example, would that be a good idea to use recursion like that? If it depends on the task, what would make it so it's a good or bad approach?
Comment: Yes it would sometimes work. E.g. quick sort, if the data-set is big enough.
Answer: Recursion isn't really about breaking problems into smaller ones or enabling concurrency; it's about solving self-similar problems.
Consider this representation of a Binary Search Tree:
public class Node
{
    public string key;
    public Node left;
    public Node right;
}

That's all you need to completely represent a binary search tree.  Why?  Because it is a Recursive Data Type; the nodes in the left and right members each form the root of a new tree, and those members each form the root of a new tree, and so on.
Here's how you find something in a Binary Search Tree:
public Node Find(Node node, string key)
{
    if (node == null) return null;
    if (node.key == key) return node;
    if (node.key < key) return Find(node.left, key);
    else return Find(node.right, key);
}

Simple, yes?
How well does this perform?  Well, you can find any item in a balanced binary tree containing four billion nodes using 32 recursions or less.
Comment: Naturally, *this* problem is trivially solved with the same number of iterations instead.
Comment: Sure, but not nearly as elegantly.  As you already know, any recursive algorithm can also be solved iteratively.  You just need to provide your own stack.
Comment: @who: Normally that doesn't happen unless you have an infinite recursion error.
Comment: what about recursion max depth exceeded error? using iterators may be clumsy but seeing it does just fine
Comment: have you tried 100 factorial with recursion?? without recursion it is possible. similar algorithm with recursion and python complains max recursion depth exceeded error (correct me if i am wrong)
Comment: @who: This isn't a debate on the relative merits of recursion vs. iteration.  I assume you know what tail recursion is?
Comment: @who: Have a look here: https://www.geeksforgeeks.org/tail-recursion/.  It contains a Factorial example.
Comment: @Robert i got your point
Comment: Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/95237/discussion-between-who-and-robert-harvey).
Answer: This sounds like a question of doing a divide-and-conquer problem in parallel.
People have done some actual implementations in SO, and it seems their strategy is to start to implement sequential calculation after reaching a particular depth. This would be similar to your example of a limited number of threads, since the max number of threads generated would be dependent on your sequential depth limit.
Please find their post here: https://stackoverflow.com/questions/16260879/how-to-parallelize-a-divide-and-conquer-algorithm-efficiently
Edit: It seems that many of the comments there are also contentious about whether this strategy is effective, but it's unavoidable having some overhead due to threading.
Answer: You can use recursion and parallel proccesing but it depend on the problem your solving. If the recursion method call it self two or more times in one run you can use threads to solve this. but if it call it self only one time it's pointless, for example factorial. factorial expect the result of n-1 in every run, so using parallel proccesing don't improve performance in this case.
Answer: To add onto the others:
Just because something is recursive, does not mean it's automatically faster or takes less memory. In fact, it can severely slow down the speed of a program. Take the Fibonacci numbers as an example. If you do pure recursion for these, something like:
int fibonacci( int n) {
    if (n = 0 || n = 1) return 1;
    return fibonacci(n-1) + fibonacci(n-2);
}

This will result in 2n function calls - Just calculating the 20th fibonacci number already means this function is called over a million times!
If instead, you solved it iteratively (or dynamically) by saving your previous numbers, you'd only need n "runs" of a loop - that's linear!
Comment: It's not O(n^2), it's exponential
Comment: And there is an even better approach using matrix-multiplication for O(log n) steps. If you don't just decide to simply pre-calculate every result fitting into a tiny `int` for O(1).
Comment: It's 1,5something ^ n. Which is absurdly bad for a problem that is easily solved in O(n) and with some maths and harder worker in O(log n) If you create a recursive function that returns both fib(n) and fib(n-1), that runs in O(n).
Answer: Quicksort can be implemented as a recursive algorithm. Now if you have say 8 cores, they can work on sub problems simultaneously. But if the sub problems are tiny, then the cost of distributing them to multiple processors is much higher than the savings.
So you would do some measuring and then find experimentally an N so that sorting N items on one processor is faster than one partitioning of N items followed by using two processors to sort each half of the result. So if your measuring tells you that the break even point is at N = 730, your code might say partition(); if the shorter half has more than 730 items then sort it using another core and sort the longer half with the current core, else sort both halfs with the current core.
You'd probably try to figure out how to partition a huge array taking advantage of multiple cores.
Answer: In my opinion recursion should only be used for problems that need a reduction step to be done at each iteration and the output used as the input for the next recursion, so in order to do the second reduction proper, the first reduction must be complete first, for problems like these parallel processing isn't feasible since it is intrinsically a sequentially dependent process.
Comment: i am inclined to agree


What are my options for getting loyalty vouchers for the 4 factions I didn't start with?

Question: I'm pretty new, and it seems like there are an awful lot of equipment types I'd have to switch factions to upgrade, how would that work, or are there other options?
Answer: The easy option is to switch faction is to 'buy' another contract. Though I would not recommend this as it is quite expensive and you better spend your credits on upgrades than switching contracts.
Alternative is to level up your ships until you can survive travel in the open space (min hard limit from the game was level 7 a year ago, but you will probably need stronger ship). On the first glance it looks nearly impossible, but still doable after some thoughts
If you worrying that you don't get currency of other factions, then i will reply that you better not spend ANY currency until your ships will reach tier 5 (level 13-15). I still spend something on T3 ships (levels 7-8), but that is probably not wise.
Because of that, having only 1 currency for a while should be enough.


Probability of unbiased die

Question: One of the numbers 1,2,...,6 is to be chosen by casting an unbiased die.Let this random experiment be repeated five independent times.Let this random variable $X_1$ be the number of termination in the set {$x:x=1,2,3$} and let the random variable $X_2$ be the number of terminations in the  set {$x:x=4,5$}.Compute $P(X_1=2, X_2=1)$. I do not know how to begin with.. please help.. I only have the pmf of x which Binomial with n=5 and p=1/6.
Answer: You have a multinomial distribution, with parameters $n=5, p_1=3/6, p_2=2/6$.  (Pedantically, it's as trinomial distribution.)
Going back to first principles, just as a binomial distribution's probability mass function is determined by taking the probability of a obtaining so many successes and failures in a certain sequence and multiplying by the count of permutations, we apply the same method to determine the pmf of a multinomial distribution with each of $n$ trials partitioned by several types of disjoint successes and a failure.
$\begin{align}
\text{Binomial Distribution} & \quad\mathcal{Bin}(n; p_1)
\\[1ex]
\mathsf P(X_1\!=\!x_1) & = \frac{n!}{x_1!\;(1-x_1)!}\;p_1^{x_1}\;(1-p_1)^{n-x_1}
\\[2ex]
\text{Multinomial Distribution} & \quad\mathcal{Mult}(n;p_1,p_2,1-p_1-p_2)
\\[1ex]
\mathsf P(X_1\!=\!x_1, X_2\!=\!x_2) & = \frac{n!}{x_1!\;x_2!\;(1-x_1-x_2)!}\;p_1^{x_1}\;p_2^{x_2}\;(1-p_1-p_2)^{n-x_1-x_2}
\end{align}$

Probability of unbiased die


Creating a managed package from two managed Package

Question: I have two different managed packages installed in my Dev org and now i have create an connector unmanaged package in it.Now i need to create managed package of all three .Is this possible?
Answer: No, it is not possible to use files from other's managed packages in new one.
It is clearly understandable, because you may download someone else's managed package, wrap it and make money with not your own work.
However, if you have code from the packages, you can download all files to sandbox as native classes, not as manages packages, and create the package that will obtain all instances.


Permissioned blockchains on EVM: are these private ledgers os it all on ETH main net?

Question: Private blockchains using EVM: is this really the equivalent of the library of tools in hyper ledger or do these blockchains run on the public main net?
Answer: They are completely separate networks, with a different genesis block.
Geth and parity support running your own private networks that can utilize the features of ethereum (and the ecosystem of tools for it), without having to interact with the public network.


Did Marx or some other marxist say something like war benefits the rich at the expense of the poor?

Question: I may be misremembering, but I vaguely recall that somewhere in the marxist (or communist) ideology there was a claim like war (and I mean actual war, not class war) benefits the rich (maybe even in all/both countries involved) at the expense of the poor (again perhaps in all/both countries)?
Sorry if this is a fairly vague statement to go by... Also it's possible the claim may have preceded Marx. Come to think of it, Marx would have probably framed it as the bourgeoisie benefitting and the proletariat losing.
Comment: Seems like a truism that applies to most any ideology.
Comment: It would make sense if he said something like it. But who knows the truth about a figure like him 150-175 years and so many governments and wars and political propaganda later?
Answer: There have been many pronouncements of this type; they became particularly popular during and after WWI; although during the war the position of the socialist parties was that not so much about the profit but the fact that the proletarians of Europe were fighting each other along national lines instead of fighting their class enemies.
From your wording, maybe you are refering to War Is A Racket, by Smedley D. Butler, a retired -at the time of publication- Major General of the USMC.

War is a racket. It always has been. It is possibly the oldest, easily the most profitable, surely the most vicious. It is the only one international in scope. It is the only one in which the profits are reckoned in dollars and the losses in lives. A racket is best described, I believe, as something that is not what it seems to the majority of the people. Only a small 'inside' group knows what it is about. It is conducted for the benefit of the very few, at the expense of the very many. Out of war a few people make huge fortunes.

He also made these comments in a socialist magazine to the same effect:

I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. In short, I was a racketeer, a gangster for capitalism. I helped make Mexico and especially Tampico safe for American oil interests in 1914. I helped make Haiti and Cuba a decent place for the National City Bank boys to collect revenues in. I helped in the raping of half a dozen Central American republics for the benefit of Wall Street. I helped purify Nicaragua for the International Banking House of Brown Brothers in 1902–1912. I brought light to the Dominican Republic for the American sugar interests in 1916. I helped make Honduras right for the American fruit companies in 1903. In China in 1927 I helped see to it that Standard Oil went on its way unmolested. Looking back on it, I might have given Al Capone a few hints. The best he could do was to operate his racket in three districts. I operated on three continents.
Comment: @Philipp Maybe I have misinterpreted the OP, but I thought he was asking to identify the text that he was remembering, more than asking the Marxist position about war.
Comment: Was Smedley D. Butler really a *Marxist*? He was certainly left-leaning, but I am not sure if "Marxist" would be an appropriate label.
Answer: The closest thing I found is a song by rebelling/deserting German soldier in the closing days of WWI.

It's all a Swindle:
The War is for the Wealthy,
The Middle Class must give way.
The People provide the corpses.

This was published in a paper by Nick Howard on the German uprisings of 1918 (collected in a 1999 CUP volume, p. 14). The same song was published (more recently) in a Socialist Review article.
It's not too clear how much this was influenced by Lenin's somewhat similar proclamations, e.g. in "The Tasks of Revolutionary Social Democracy in the European War" (1914):

the necessity of using weapons not against one's own brothers, the hired slaves of other countries, but against the reactionary and bourgeois governments and parties of all nations

even though that doesn't talk about profit. Separately, Lenin said in his May Day speech (1915)

"War is a "terrible" thing? Yes. But it is a terribly profitable thing."

I guess Sartre should get a mention here for saying it more concisely (although not as precisely) in The Devil and the Good Lord (1951):

When the rich wage war, it's the poor who die.

And as "the rich man's war and poor man's fight" it goes back to the US civil war.

To answer @gerrit's request for the German original of the song; it's given in R. Bessel, Germany After the First World War (Oxford, 1993, p. 1)"

Es ist alles Schwindel:
Der Krieg ist für die Reichen,
Der Mittelstand muß weichen,
Das Volk, das stellt die Leichen.

A bit more searching finds a book in German: H.C.Grünefeld "Die Revolution marschiert: 1806 - 1930" with a several songs on the same theme (around p. 341 in vol 2)
Comment: @gerrit: actually, I did eventually, see edit.
Comment: @Fizz Nice!  I found some more sources of the same, and it looks like it's supposed to be *muß*.  I expect your source dropped the ß accidentally, perhaps due to the non-standard letter.
Comment: Perhaps the question was inspired by a more recent song: Civil War by Guns n Roses ("I don't need your civil war, it feeds the rich but it buries the poor.")
Comment: Do you happen to have come upon the original German version of this song?
Comment: @gerrit: sadly no. I realize it doesn't rhyme much in English.
Comment: @Fizz. If you leave two spaces at the ends of lines, linebreaks are preserved. Then you don't need a blank line between each line. Makes poetry formatting look better.
Comment: @gerrit: yeah, book in English... some editor probably messed up.
Comment: @Ivana: I was aware of the GnR song, but also was sure of having it read in more "serious" works.
Answer: What you describe, is referred to by the term "imperialism", i.e. a policy that involves a nation extending its power by the acquisition of lands by purchase, diplomacy or military force.
While you can find some references on imperialism in Marx, they are mainly focus on what he describes as primitive accumulation, where the origins of capital are explained, as well as colonization.
The actual analysis of imperialism is mainly done by
1) Lenin, in "Imperialism, the Highest Stage of Capitalism (1917)", where he describes the function of financial capital in generating profits from imperialist colonialism as the final stage of capitalist development to ensure greater profits and
 2) Roza Luxemburg, in "The Accumulation of Capital: A Contribution to an Economic Explanation of Imperialism", where she argued that capitalism needs to constantly expand into noncapitalist areas in order to access new supply sources, markets for surplus value, and reservoirs of labor.
As far as historical records are concerned, though they cannot be described as analysis of Imperialism (since the latest is a more recent term), but can be seen as an materialistic-dialectic view on history, traces can be observed even in ancient Greek writing, ex.
1) Euripedes, Helen, where the it is argued that the Trojan War was not actually made for the beautiful eyes of Helen, but for greek expansion over the Aegean Sea.
2) Aristophanes, who clearly associates war, pillages and destruction with the end of the self-sustained village society
3) Thucydides, the father of scientific history, when analyzing the economic background of athenean expansion, during Peloponnesian War.
4) In Aristotle's Politics, where he explains how wars are employed to provide the society with new labor power (slaves).
Comment: This is the best answer, referring to the canonical writings of Luxemburg and Lenin.
Comment: +1. I didn't read the existing answers before posting my own, and I can see that this references much of the same stuff that I did.
Answer: There are many Marxists who have mentioned war. At heart, Marx is an economic determinist: literally everything in society happens because of economics. Here are a few you may be thinking of:
Marx
Although he doesn't specifically call out war, in the Communist Manifesto Marx describes the modern world as having a problem of too much stuff. Industrialized society produces far more than is needed, which is terrible for profits. The bourgeoisie use "commercial crises" to destroy the extra stuff, so that they can justify producing it (and selling it) all over again. It is no stretch to see how this applies directly to warfare: arms manufacturers need us to use ammunition, vehicles, and other goods in order for them to keep making profit.
Of course, the same also applies to many other forms of social crises.
Source: Section I of the Communist Manifesto (pg.17 here).
Rosa Luxemburg
Rosa Luxemburg is perhaps more famous for her views on war. In The Accumulation of Capital she argues that the central drive of all capitalist societies is to open up new markets.  The entire last chapter is dedicated to capitalism and war.
A few of her arguments:

Warfare is a way of appropriating the means of production. Capitalists in industrial societies use warfare to acquire labor, access to commodities, farming land, and more from others.
Governments purchase large quantities of good to support warfare. This is of course valuable to the industries that produce those goods.
Through taxes (both direct and indirect) workers' wages are taken from them to support the military. More workers are pressed into military service and to work in industries that support the military. Workers don't need that military (because it's purpose is to open markets and seize means of production), so workers are forced to support their own and others' exploitation.


Flex NetStream.Step doesn't work per-frame

Question: I've got a Flex 4 project, and a FMS 4 (Flash Media Server) server that streams mp4 streams from recorded f4v files.
My video control is a subclass of Spark/components/VideoPlayer, and I have buttons for stepping back and forth in a video. We need to be able to see each frame individually but it seems to only update the image every four or five frames (it varies, even within the same video).
Here's the code, nothing particularly advanced:
<code>public function stepButtonClick(direction:int, shiftDown:Boolean):void {
    //Step forwards or backwards
    //NOTE Steps 10 frames if the shift key is held
    var stream:NetStream = getStream();

    if (stream) {
        stream.step(shiftDown ? (direction * 10) : direction);
    }
}
</code>
Any idea what I can do to fix or debug this issue? Could it be that it's only showing I-frames (keyframes)?
Answer: Stepping can only be done to a keyframe, so if you want this make sure you set keyframes close enough, but remember these have a tremendous impact on file size.
Also, RTMP streaming is not nearly as good at this as as Http Dynamic Streaming...
Good luck!  If you need further help let me know...
~ JT


Hosting asp.net application inside PHP app on IIS 7

Question: we have a dedicated server running IIS 7. There is a PHP site (wordpress) running from the server. We want to be able to run an asp.net app on the same server, preferably from within the php site. Any ideas on how to do this?
Comment: You mean Virtual Directories under the main PHP "website?" You shouldn't have any issues with this. Simply enable "ASP.NET" from within "Manage Your Server" (Add/Modify Role -> IIS -> ASP.NET [x]).
Comment: Yes, I've added a Virtual Directory to the asp.net app under the PHP website. I don't see an option under Add Roles for ASP.NET, but I'm fairly certain that's already activated.
Answer: IIS doesn't care at all what kind of "application" you run on it, it doesn't even have any concept of "application" as we humans could mean it (*). It only sees files, and chooses what to do with them based on their extension: simply serve them to the client if they have .html, process them with the classic ASP engine if they have .asp, use the PHP interpreter if they have .php, and so on up to .aspx files, which are handled by the ASP.NET engine. Those interpreters of course have to be installed and enabled on the web server, and the relevant file extensions have to be mapped in order for IIS to know what to do with them; but once this is done, IIS will happily serve any file it can understand, regardless of its position either in the file system or in the web site structure.
So, to sum it up: yes, if the PHP and ASP.NET engines are installed and enabled on the server, you can mix .php and .aspx (and any other) files any way you want, and they can of course call each other.
(*) Yes, yes, we could talk for hours about application pools and worker processes; this just doesn't change the main point, though.
Comment: It's great that this is possible, but it's not working on my server. I've looked at the "Handler Mappings" for the php site and it includes mappings for .aspx files, but I'm still getting a 404 when navigating to the asp.net application.


Is it possible to respec (reset) the passive skill points?

Question: So far, I've been spreading my passive skill points here and there in the huge passive tree.  I'll  probably want to change it to a more clever distribution later, when I'll have a better understanding of the game.  Is it possible, and how ?
Answer: There are ways to make small changes to your skill point distributions in the passive skill tree, however the intention is not that you simply 'reset' the skill tree and instead make a new character if you want to make a large quantity of changes. This is detailed on the Path of Exile website:

If you want to adjust your passive build during gameplay, there are Passive Skill Refund points available from quests or relatively rare items in the game that can be found or traded for. Fixing mistakes with a character build or improving small-medium sized aspects is relatively easy, but our intention is that players who want to try substantially divergent character builds are encouraged to play a new character through the game, organically leveling it up rather than just respeccing into it.

You'll get a few respec points from quests which each allow you to remove a single skill point, so you can try out big nodes and undo little mistakes. This doesn't remove the need to plan your skill point distribution ahead and you'll still have to pay attention.
You can refund individual skill points by using Orbs of Regret (purchased from Yeena in Act 2) but if you're level 20 or above it's easier to just make a new character.

It is not possible to completely reset your passive skill tree.
Comment: yes you are - which is why once you're past level ~20 it's easier to just reroll your character. They're called prerequisites for a reason!
Comment: When using a respec point, are you restricted to only removing passives that are at the end of your progress down a specific path (i.e. no skills that are prerequisites for another skill you've taken)?
Comment: I figured that was probably the case, but it's good to have confirmation.  Thanks!
Comment: From time to time, you are given full passive skill resets when GGG launches a major update. This was the case for Awakening and Ascendancy. Depends on how often you play, though.


Where is all the Brute's base armor

Question: Brutes are protected by thick, metal plates that can be shot off. Where are all the base armor plates? Does each armor plate require the same amount of damage to shoot off? Can the Brute pick up armor like the Cannibal?
Answer: I believe that all plates take the same damage to remove, and I don't believe they pick them up.
Confirmed on xbox.
Answer: A direct quote from Bioware programmer Brenon Holmes is illuminating, and provides some interesting information on the intended state of vulnerabilities:

Ah... hmm - I'm not sure why your empirical testing would have come up with some of that - but here's how it's "supposed" to be.
Brute

Takes reduced damage in the right arm
Takes greatly reduced damage in the claw
Armour Plates absorb damage until breaking (best to aim for exposed flesh, probably base of the neck?)
No other weak points
Comment: it doesn't exactly say *where* those armor plates are though, just that they absorb damage.
Comment: @yx. I agree it is only a partial answer so far. But it does highlight that not armor is not uniform.

Where is all the Brute's base armor


How can I post a user name for my account

Question: Currently I am listed as "user23299429", because I had difficulty when signing in. I would like to be listed as "Still curious at 82". Please let me know if, and how, this can be done.
Answer: Welcome to the site! Your username can be changed in a couple quick steps by going to your profile page and editing it. You can choose whether you'd like to apply the change to just one Stack Exchange community or all of them. Note that you can only change your username once every 30 days, though.


Is it possible to add JSON code to hide and show other rows based on column value?

Question: I am using view formatting with JSON and wondering if its possible to add
button that can sort, hide and show other rows based on their column value, like only show items in toys department store and hide other departments, sports, etc.
Answer: You can create links to your view with filter query strings. Here's an example of how to do that with a multi-choice field:
{
  "elmType": "a",
  "txtContent": "=join(@currentField,', ')",
  "attributes": {
    "href": "=@currentWeb + '/lists/Allies/Orderable.aspx?FilterFields1=Drinks&FilterOp1=Eq&FilterValues1=' + join(@currentField, '%3B%23')"
  }
}

In the example above, the list name is Allies, the view is Orderable.aspx, and the internal column name is Drinks all of which are hardcoded in the format as there isn't yet a way to pull this information from context.
You can do the same with sorting by using additional query strings. For example adding sortField=PhoneNumber&isAscending=true would sort the view by the column with the internal name of PhoneNumber.
The easiest way to make sure you're getting these query string values right, is to apply filters and/or sorts to your view and note the query strings applied in the URL. Then build your links using those and plug in dynamic values (from the current list item) as needed.
Answer: As far as I know,if we want to hide an item in list,we need to add Conditional class to list, but there is no original class that can hide the item.
All classes we can use:

Of course,we could use custom class,then we need to inject our custom css through spfx.
https://tahoeninjas.blog/2018/05/08/inject-custom-css-on-sharepoint-modern-pages-using-spfx-extensions/
Answer: I think this is not possible using JSON view formatting as you cannot get the column values from another rows/list items in JSON code.
You can only access the column values from the same list item/row like [$AnotherColumnFromSameRow].
Where AnotherColumnFromSameRow is internal name another column from same list item/row. You can get the internal name of your column by following this article: How to find the Internal name of columns in SharePoint Online?
Official documentation: Use view formatting to customize SharePoint


Where is my old Browser stuff?

Question: I was using Firefox and had loads of bookmarks set up.
I install Tor expecting it to be an alternative browser but it has taken over all my browsing. Can I get my old browser 'as-was' back?
Thank you for any help.
Answer: The tor browser bundle is a standalone firefox,
the bundle is run independent from any other browsers installed on the system.
If you downloaded the bundle, unpacked it and then run it from that folder then it will not interfere with other browsers on your computer.
I fail to see how it can 'take over', please elaborate on this if possible.
(Where you downloaded from, how you installed it, how you run it.)
Answer: The Tor browser is a separate browser. You should be able to just start Firefox like you always did.
Answer: I often run firefox and TOR at the same time.
They do not interfere with each other.
Maybe you upgraded firefox without backing up your bookmarks first

Where is my old Browser stuff?


What could be possible features of a textual word?

Question: I wish to construct feature vectors of words in a document and then calculate their linkage distance to detect anomalies. My question is how can I model these features ? If possible please give an example so I can understand better. Further how distance calculated will vary from the text that is anomalous and the one that is normal ? (Please refer to D. Guthrie, PhD. thesis for more clarification).
Answer: That is a rather broad question. If you are on a document level, you could (after removing stop words) determine the most important words in your corpus by calculating the tf/idf measure https://en.m.wikipedia.org/wiki/Tf–idf
Then you could define a vector over the top n words and represent every document as a vector of the relative frequencies of the top n words in that document and work on these vectors.
On a sentence level that could work as well, on a word level obviously not. Anyway, information retrieval and computational linguistics are a rather large research area. Maybe the best way would be to start with a book that provides a good overview.
Since you asked for some more specific recommendations:
If you can get access to (or actually want to buy it), definitely this one: Speech and Language Processing: An Introduction to Natural Language Processing, Computational Linguistics, and Speech Recognition.
You can also take a shot this: Sentiment Analysis and Opinion Mining this is probably not your focus, but it covers feature representation to some extent and is for free.
More like a handbook with practical approaches is: Programming Collective Intelligence, look for it at Google, it is also available for free.
Otherwise if you want to look for yourself for books at a library or so, your keywords are "Computational Linguistics" and "Natural Language Processing".
Hope this helps
Comment: What I usually find helpful for introduction and good references are open stanford courses. For Natural Language Processing, I found this one helpful: (http://web.stanford.edu/class/cs224n/) in the section Textbooks and Readings are futher good references to books if you don't want to go through the slides.
Comment: Would you please mention a book or two that might help.
Comment: I edited my answer.


How do I change the WordPress Address URL only and still login to wp-admin

Question: The story so far:
I added a distribution on Amazon CloudFront (randomString.cloudfront.net), then added a cname (cdn.mydomain.com) and finally created a cname record on the DNS server - pointing cdn.mydomain.com to randomString.cloudfront.net.
Next, I changed the Wordpress Address (URL) in General sittings to switch all URLs in my theme from mydomain.com to cdn.mydomain.com, the site loads amazingly fast.
The contents are served from AWS Cloudfront; however, I am unable to login to wp-admin (probably coz the 'Site Address' is still mydomain.com.
If I switch both WordPress Address and Site Address - the site fails to load with the error: multiple redirects.
How can I achieve this? Use the cdn.mydomain.com as WordPress URL and still login to wp-admin - Is this even possible?
Thanks in Advance.
Answer: For anyone else in this dilemma, I took a different approach
I set the origin as cdn.mydomain.com on AWS Cloudfront and added cname www.mydomain.com
all working now :)


How to find the most recently edited file in NSIS

Question: I have an NSIS script that pulls other installers from a local share.  Some of these update very often.  Rather than push out a new NSIS script every time, I'd like the script to look for the most recent installer matching a pattern in a certain directory.  Is there a plugin or a Windows API that I can call from NSIS to do this?
Answer: You can execute batch files with the !system command (at compile time)


Rectangle with gradient around entirety of shape . - Illustrator

Question: How can I make a rectangle with basically a fade to middle gradient on both vertical sides and also gradients from the bottom of both horizontal sides of the rectangle? I cant use radial because that is equal gradient on all sides where I want the gradients on the horizontal sides to end quickly, because it's a rectangle. Get it? If i try to do clipping with the rect it gets weird because the gradients don't match. Thanks.
Comment: I'm having a difficult time envisioning what you are seeking.
Answer: You can place a microscopic scaled copy of the rectangle in the middle with different color and make a blend

In the bottom there's a colored curve in the background to show how it works with transparency. The red rectangle in the blend above is selected and its color is changed to the same blue as the bigger one has, but the opacity is 0%
You cannot fade the apparent diagonal rays for ex. by changing the shape in the middle. The rays are a consequence of the fact that the gradient must be less steep towards the corners.
If you cannot accept the rays, you can fill an exact square with a symmetric radial gradient and then squeeze the square to the wanted aspect ratio.
In theory you can also proceed with gradients. With help lines (=diagonal and a perpendicular one) you can place a linear gradient:

Make a flipped copy and combine the rectangles with a blending mode. I used multiply.

The result can be used as opacity mask for a solid color rectangle:

The result isn't as linear as with blending. That can be helped by moving the half stop markers of the gradient towards the ends.


Simply Connected Domain of the plane and the Jordan Curve Theorem

Question: While reading Markushevich's complex analysis book, I realized that his definition of a simply connected domain differs from the one I have seen before. He takes the Jordan Curve Theorem for granted, and denotes the interior of a closed Jordan curve by $I(\gamma)$. Then he defines (pages 70~72 of vol.1) ;

A domain $G$ is simply connected iff whenever $G$ contains a closed Jordan curve $\gamma$, $G$ also contains $I(\gamma)$.

Then he shows some interesting results, such as a bounded domain is simply connected if and only if its boundary is connected (of course, with his definition).
My question is : Does the above definition coincides with the usual one, given by the condition $\pi_1(G)=1$ for the fundamental group of $G$?
I know that this has to be the case since otherwise the whole theory would break down.. but how exactly can we explain this equivalence? Do we need the Jordan–Schoenflies theorem?
Any advice is welcome. Any reference is also welcome.
Comment: Your premise is wrong. Markushevich doesn't define *simply connected domain* the way you described it. The definition is not on p. 70, but rather on p. 67: "A bounded domain $G$ is said to be *simply connected* if its boundary $\Gamma$ is connected."
Answer: Here's a rough idea as to why you might expect these definition to be the same. You might run into more problems making this precise, but this should hopefully give some intuition.
Suppose we have a point in $G$ but not the interior of $\gamma$. If $\pi_1(G)=1$ then we can contract $\gamma$ to this point. But then it very much looks like the point $x$ is in the interior of $\gamma$! (This should rely on the fact that the curve is simple)
The other direction seems a bit more difficult, since the curves we consider need not be simple. But for any Jordan curve, using the property that its interior is contained in $G$, we can use "straight line homotopy" to map contract it to a point $x\in I(\gamma)$ (map every point along a straight line to the point $x$). Then in the general case you could argue in two ways. The first would be to somehow use $\pi_1(S^1) \cong \mathbb{Z}$ to say that the curve should be homotopic to a Jordan curve. The second could be to consider each bounded connected component of the curve. Each is bounded by a Jordan curve, so the same argument would say that there is no puncture or anything in this component.
In any case, thinking about how the alternative definition of simply connected rules out non-contractible loops should get you most of the way there to understanding this. I would recommend drawing lots of pictures!
Comment: Would you please provide a reference to a source where I may find a detailed proof?


In Facebook, if I share some post from others timeline onto my timeline, who will be able to see it?

Question: In Facebook, if I share some post from others timeline onto my timeline, who will be able to see it and where? Also who will be able to see it and where when I tag friends while sharing the post onto my timeline?
Answer: You can always set the privacy.
About Privacy

Once you tend to share a post it opens a popup in that we can have
  options to add extra content(Optional) about the post and also we will have
  privacy option to choose between Public/Friends/Custom/Onlyme

Tagging Friends

You can tag your friends by clicking on image and by choosing Tag
  option or simply you can tag your friends in the popup content by
  calling them in this way @yourfriendname
Answer: If your timeline is viewable by the public, this post will be viewable by the public. If it's only viewable by friends, it will be viewable by friends.
Answer: From Facebook help center

If you want to change the audience of a post after you've shared it, click the audience selector and select a new audience. Remember, when you post to another person's Timeline, that person controls what audience can view the post. Additionally, anyone who gets tagged in a post may see it, along with their friends.


Can I add Defiance to my Steam account?

Question: I've purchased Defiance, and I'm familiar with adding external games to Steam. My question is, can I add Defiance to my Steam account where I would be able to download it from Steam directly? I did try adding the key in the retail box.
Comment: @Nolonar little wonder, they're desperate for people to use Origin.
Comment: if you tried adding the key and it didn't work, then no, you can't do it without repurchasing it through steam
Comment: You could ask the publisher if they're willing to provide you with a Steam key, but there's no guarantee it'll work. When I asked EA for a key for *Crysis* and *The Sims 3*, they answered: "*We generally do not provide keys for platforms other than our own*"
Answer: If you purchased Defiance outside of Steam, I don't believe you'll be able to add it as a "native" Steam game, without already having a Steam key. The retail key you have will only work for a retail copy, or a direct download. Like you said, you'll be able to add Defiance externally though.
It also depends on where you purchased the game from. Some companies or publishers provide a Steam key if asked (or do so automatically upon purchase). Though, as Nolonar has stated, there's no guarantee for this. In general, I would say you need to buy a game from steam, in order to download the data required directly from the Steam servers.

Can I add Defiance to my Steam account?


Is it necessary to traverse every letter in the tape of a Turing Machine?

Question: Say I want to make a very simple Turing Machine that accepts only strings that contain one or more a's. Can I simply send have the machine move a HALT state once it reads one a, even if there are many letters after that first a? Or would this be bad practice or unacceptable for a Turing Machine?
Comment: Depends on the exact definition you are using.
Answer: To the title question - no, to the flipped version of the same question in the body - yes. It is typically fine to halt without processing the entire input (however see Raphael's answer for certain technicalities in this respect).
There's not really such a thing as "good" or "bad" practice with a Turing Machine in the sense that there are "good" and "bad" practices when programming on a "real" computer.
As they are theoretical models for computations, they are at their best when they prove (or assist in proving) what you need to prove in as clear and direct manner as possible. In this light, as long as your machine only performs permissible actions, then everything is fine - so no cheating, but beyond that it's all good.
Comment: Thanks. I wonder also if it depends on the book (if mentioned at all). For example I have a computer theory book that makes the tape infinite only in one direction, not both.
Comment: @btalbot, the tape can be infinite in one or both directions, they're equivalent in terms of computing power, so even with that, you can use whichever makes sense for what you need.
Answer: There are definitions of Turing machines in which the output is defined to be the tape content from the head on to the right (until the first empty cell) at termination. Depending on whether you allow your TM to (re)write empty cells, you have to more to the right or erase most of the input, or at least insert a gap after your output.
There are special (sub)models for deciders and acceptors. In these, there is no output on the tape; there are special (non-)accepting states in which the TM halts. In such models, you can terminate whenever you want without having to worry about the tape content.


Biber: Does it really need incoming connection ?

Question: My windows 7 warned me that biber.exe tried to establish incoming connection. I wonder why biber would need it? I blocked the connection for a while.
Answer: biber is a Perl script and to make it run without installing the needed Perl libraries, the exe comes with all libraries which must be extracted from the file. This happens only once. However, I am not a windows user, so that I do not really know what biber checks for windows.
Comment: I'd be very interested to see what it was trying to do - I'm the current biber maintainer and I wrote the packaging/distribution code. As mentioned by others, the reason the binary is large is because this is essentially a whole perl tree, including interpreter which unpacks on first run to a temp location (see the very clever PAR::Packer perl module). There is nothing in biber itself that would make a network connection but perhaps something in the PAR::Packer framework or the LWP libraries does. Nothing to worry about though.
Comment: Indeed, bibber.exe is rather big (13Mb). However, I haven't seen any indication of unpacking and installing something during first run. So, I will keep it blocked by Windows firewall.
Comment: On Linux it extracts all files into the tmp directory. The reason why the first `biber` run always takes a long time.
Comment: @Igor: It does unpack on first run (as @Herbert says), but I think the net access thing is just a Perl standard check and is not actually required.


Do I need transit visa for Dublin airport terminal 2?

Question: I have a Canadian Travel document(not Canadian passport) and I plan to travel from Canada to Germany but I have a stop in Dublin (Terminal 2). I arrive (5:00 am) and leave(6:30 am) Dublin terminal 2 on the same day. Do i need transit visa for that?
Comment: Some people claimed in comments that Dublin/Ireland is in the Schengen area but that is not true.
Answer: 1954 Convention Travel Document holders:

Click here to check if you need an Irish visa
See full country list: Visa & Non-Visa Required Nationalities
...
For all other situations, regardless of where you live, or the nationality of your family member, your needing an Irish Visa or Preclearance is based on:

your nationality (if you are not a refugee); or
the country which issued your Travel Document (if you are a refugee).

All other 1954 Convention Travel Document holders will, unless otherwise exempt (see exemptions above [below]), need a visa.

Exemptions: from Belgium, Czech Republic, Denmark, Finland, Germany, Hungary, Iceland, Ireland, Italy, Liechtenstein, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovak Republic, Spain, Sweden, or Switzerland,

This information is also contained on this page with a additional note:

Recognition of Convention Travel Documents - Immigration Service Delivery

Note: If you possess a convention travel document issued by another country, you will require a visa.

Since Canada is not listed here, it looks as if you require a Transit visa.

Transit (including Transfer Visa) Advice - Immigration Service Delivery
...
Transit passengers making connections at Dublin Airport should be aware of the following: If both your arrival flight and onward connecting flight are in Terminal 2 between the hours of 04:00 and 16:00 on the same day, you can use a transit visa in this case.
...
Comment: I think this answer reaches a correct conclusion (the OP needs a visa) but takes an unnecessary detour. [This Irish Government webpage](https://www.irishimmigration.ie/at-the-border/transit-including-transfer-visa-advice/) directly addresses the transit visa question. As to Irish transit: Refugee Travel Documents aren't mentioned at all. Because we don't know the OP's home country, we don't know (yet) if the OP needs a transit visa. I will post a separate answer.
Comment: @DavidSupportsMonica Your link is the same as my second link ('Transit (including Transfer Visa) Advice') and leads to my first link which contains a popup dialog from where the relavent information was taken from (and cannot be linked to directly).
Answer: This Irish Department of Justice webpage specifically addresses the Irish Transit Visa. The page says:

Transit Visa Required Countries

Afghanistan
Albania
Cuba
Democratic Republic of Congo
Eritrea
Ethiopia*
Georgia
Ghana
Iran
Iraq
Lebanon
Moldova
Nigeria
Somalia
Sri Lanka
Ukraine
Zimbabwe

*Travel from Ethiopia to USA or Canada or Ethiopia from USA or Canada, via Ireland.
You do not need an Irish transit visa if you are a citizen of Ethiopia and are travelling on your national passport directly from Ethiopia via Ireland to the United States or Canada. You must have permission to travel to the United States or Canada.
You will not need a transit visa to travel directly from the United States or Canada back to Ethiopia via Ireland. You must have been legally in the United States or Canada at the time of your departure.

Note that the page addresses only the identity of the traveler's home country, and does not mention Refugee Travel Documents. Holding a Refugee Travel Document, or the identity of the country that issued the Refugee Travel Document, is therefore irrelevant.
Thus, if your home country is listed on this Irish Government webpage, then you will need a Transit visa to change planes in Dublin, Ireland.
You may also need a separate visa to enter Germany, which is in the Schengen area and follows different visa and entry rules.
Comment: Relevent is that the OP has a **Travel document** and not their citizenship. See my answer where this is quoted and that a **Travel document** issued  in Canada is not exempted from the visa requirement.


Why does Eratosthenes method for calculating the circumference of the Earth requires the city of Alexandria and Syene to be in the same meridian?

Question: I'm reading a book where the author claims that in order for the method of angles and proportions used by Eratosthenes to work, the two cities would have to be located in the same meridian, or at least reasonably  close. Why is this the case? Couldn't I meassure the shadow on a completely different meridian and still figure out the circumference? After all, the stick on the ground and the well on Syene still both point towards the center of the Earth.
Answer: The main reason is noon occurs at the same time on a meridian.
The ancients didn't have accurate ways of keeping time, but everyone could tell when noon was because of the position of the Sun in the sky. By prior arrangement it is easy to agree to take the measurements on a particular day at noon. By being taken at noon they know that the measurements are taken at the same time, which was critical to the calculations.
Comment: That sounds like a really good reason that I didn't consider, since they didn't have precise clock back then, it makes sense. I also thought another reason might be that angles at a different meridian are actually composed of two elements, or two angles I guess I should say. I don't know how to explain it since I lack the knowledge but there would be two angles to meassure instead of just one, and I think that can also be a factor right?
Answer: The reason mentioned in the answer of @zlaaemi is of course the most important one: the ancients could easily measure the difference in latitude, but not the difference in longitude.
The "problem of longitude" was solved only in 18 century.
But there is also another reason: spherical trigonometry did not exist yet at the time of Erathosthenes. As far as we know, it was developed 300 years later (by Menelaus of Alexandria). So the problem with two laces on different longitude was probably too difficult at the time of Erathosthenes, even mathematically.
Answer to the comment. Suppose you have two cities A and B. To estimate the radius of Earth you need to measure an arc of great circle a) in degrees, and b) in some terrestrial units (say in miles). To achieve a) you need to compare some astronomical observations, it is easy to measure the difference in latitude, but to measure the difference in longitude, your observations must be simultaneous.
And how do you achieve this? After 18 century you can transport clocks. But this was not available. In principle, one can use star occultations by the Moon or Lunar eclipses, but again computation of the longitude difference from such observations requires a lot of spherical trigonometry.
There are in principle two possible ways to solve b): first, to travel directly from A to B by an arc of a great circle, and measure the path; this is already a big problem: how do you know the direction of the great circle? Even compass (which was not invented yet) will not help. Second way is the direct triangulation (the method used in 18 century). But to do this you really need a lot of spherical trigonometry and very precise measurement instruments. None of this was available to Eratosthenes. So already problem b) was unsolvable at that time. I recall that they started to practice sailing on the orthodromy (the shortest path) only in the later part of 19 century, mainly because of fuel economy, but also because they just did not know how to do it before that.
Comment: Would you mind telling me how would solving the problem mathematically look like for the case of two locations with different longitude? One directly above the sun with no shadows and another one with shadows.
Comment: Thanks for the thorough explanation, so just to confirm I understand, problem b was unsolvable at the time because it required the ancients to travel along a great circle to meassure distance between the cities, but if the two cities are on the same meridian this is not a problem because you can either travel straight south or straight north and this was something the ancients were able to do, correct?
Comment: You understand correctly. Though even traveling straight South/North is not always easy (they had no compass!). You have to determine your direction by Sun and/or Polar star, but this is not very accurate and not always possible (depends on the weather, clouds etc). BY the way, Polar star was not in its current place at that time.
Comment: Nevertheless, they knew somehow that Alexandria and Siena are approximately on the same meridian, probably from many travels.
Answer: Below, B is X km north of A, while C is X km west of A.
Since A and B are on the same meridian/longitude, the circle through them is a great circle, whose length is (approximately) the same as the equator and is what we want to measure.
In contrast, A and C are not on same meridian/longitude (instead, they are on the same parallel/latitude). The length of the circle through them is smaller than that of the equator and is not what we want to measure.
Answer: All meridiens are great circles i.e. each is equal to the circumference  of the earth. Latitudes, on the other hand, except for the equator, are not and would give the wrong result for the circumference of the earth.


Ingress factions: only appears to be one group in my city

Question: I'm trying to sign up for Ingress and choose a faction. I like the idea of playing for the underdog to try and balance things out, but there literally appears to be only one faction in my city. The Ingress map shows a score of 818 for one team and a score of 0 for the other. If I join the 0 scoring team, will I just be bored because I can't do anything? If I join the team everyone else is on, will I bored? I don't understand the game enough yet.
Comment: @TimS. Also note that it's summer and a lot of the Ingress players are on vacation. PoGo is getting all the attention in media right now unlike Ingress (I've been playing since 2012). We'll see in a couple of months time what gives.
Comment: That's because everyone is mesmerized by Pokemon GO right now. Ingress was pretty cool in it's day, but I think it's time has passed, unfortunately.
Answer: If you're talking about the "Regional Scores" section in the "Intel" section of the Ingress app or the "Regional Score" line on the Intel map, that score just displays the current status of the current running cycle. If you're living in a sparsely populated region that score won't change too much in the future but if you're not then it could be just a momentarily score. Watch it for further developments.
In any case your movements surely would be recognized by players of neighboring regions and if you insist on playing the game they surely will contact you because Ingress players always need players from neighboring regions for bigger fields and are in the lookout for persistent newcomers.
Ingress is still being consistently played by both its core players and the newcomers. Please don't hesitate to join this growing community.
Answer: When you join Ingress, your main focus is to level up quickly.
If there aren't many neutral portals around your place, and you choose to be underdog, you may have a difficult start - where you can only hack enemy portals but can't really capture anything or create links and fields.
If there are, I'd choose the underdog path, it's much more fun.
Use the intel map to decide.
Comment: I made this choice in the town I live in. There was only one resistance player who owned the whole town. He is level 9. I decided it would be much more fun to go against him so I am slowly gaining levels (currently level 6) and getting strong enough to take down his portals and then send him messages which is fun! I managed to get some big boosts in AP by claiming portals in other towns when I was out for the day, that definitely helps!
Comment: Hacking enemy portals also gives points so even low level players can get to a higher level. Trying to find weak portals and eliminating them or fields also provides you with much needed AP. Asking for someone to help out from out of town also can give you a boost and they might enjoy doing missions or getting unique captures. Also, deploying on top of other's resonators gives AP.
Answer: Personally, I have a lot more fun in the enemy area.
That's were I make AP and I like to blow things up.
However, it might be difficult for beginners since before level 6 attacking portals is mostly useless.
But, once you're 6+, it's quite fun to go to a green (I'm blue) area destroy it all, capture, link, field!
Comment: This doesn't really address his question, but rather  seems to address the opposite of what is being asked.


Delete selected comments of a particular node?

Question: Is there any module in Drupal 7 for deleting selected comments at one go for a particular node?
Comment: There will be another tab with content in admin  section where all the content and at url admin/content/comment
Answer: You can do this with Views Bulk Operation module. Follow the steps:

Install Views and Views Bulk Operation modules and enable these modules.
Create a View of Type "Comment".
Change the Views Format show from 'Comment' to 'Fields' under Format section.
Change the Views Format from 'Unformatted list' to 'Table'.
Add Bulk Operation:Comment, Comment:Title and Content:title fields under Fields section.
In step 5 When you chose Bulk Operation: Comment select Delete Item under SELECTED BULK OPERATIONS setting.
Add Content: Title filter criteria and expose this filter So that you can filter comments of a particular node.
Comment: Thanks:) @MutantMahesh. I just needed something like that.


Why Ubuntu Installation asks to disable Secure Boot?

Question: I installed Ubuntu 17.04 (Zesty) on my Asus Laptop, Intel Core i7. When I was prompted for questions for the install such as disk partitions and other stuff, I was asked to disable Secure Boot if I wanted to get 3rd Party software for WiFi, graphics and sound. Now my question, should I disable it and comply, or leave it as enabled? Plus, what is secure boot and what will happen if I disable it? Thank you
Answer: If you don't disable Secure Boot, you will be unable to install 3rd party kernel modules, like proprietary video or wireless drivers.
We don't know if you need any 3rd party kernel software or not.
You can keep it enabled if you don't need them. Another limitation will be that hibernation doesn't work in Ubuntu with enabled Secure Boot.
Secure Boot is a mechanism in UEFI that checks signatures of OS kernel and doesn't let to load unsigned OS's or modules.
Nothing terrible will happen if you disable it. It is not a very useful feature in practice.
Answer: Basically secure boot may prevent you from loading some driver you installed which can be quite frustrating.
Personally I disagree with the seeming ubiquitous advice to turn off secure boot, works just fine on my hardware with secure boot enabled. IMO leave secure boot enabled unless you have a problem with it, no reason to blindly disable security features.


Can I bring my parents back together?

Question: I am fairly young, not a teenager yet. This morning, my parents had a fight and my mom said she was going to stop cooking for my dad. At lunch, I spoke to my dad about apologizing and recognizing my mom's importance in the family, but he ended up making lunch for himself. I am scared my mom would start taking more and more things away until they reach the breaking point. Is there anything I can do to prevent this from happening??
Comment: I'm voting to close this question because OP is an underage user.
Comment: This has been asked - and even answered - a large number of times. Search "divorce" and you should get some helpful hits. Ultimately the answer is always that you can't control , nor are you supposed to, the actions of others. It doesn't sound remotely close to a breaking point to me, though. It's great that you recognize the value of an apology, even if others do not agree.
Answer: Ultimately, responsibility for solving your parents' relationship problems lies with your parents.
There are things you can do to encourage your parents to work out their differences.  But the fate of their relationship is in their hands, and if they are unwilling to work to solve it then there is very little you can do to force them to.
The best thing you can do is to try an understand the point of view of both your parents, so you can help each of them understand the other.  And just your presence gives your parents an incentive to work out their difficulties.
Your father making himself lunch isn't necessarily a bad sign
You can see a breaking point for your family where your mother refused to do an increasing number of chores until it is too many.  But there's a second breaking point, where your mother is handling too many of the chores herself and can no longer deal with the weight.
I do not know what the equitable division of labor is in your family.  But for many, many families, women do more than their fair share of the chores.  There is a reasonable probability that your father making his own lunch is a sign that your family is moving in a healthier direction, rather than a dangerous one.
Far more worrisome would be if your father refused to make himself lunch, starving himself to guilt trip your mother, or even ordering out.  Making his own lunch might be a sign that he has acknowledged your mother's point.
Take a look at the work that goes into making your family household work.  This is a hard thing to do, and there are many little things that are easy to miss.  Cooking, cleaning, and making money are obvious, but "scheduling doctors appointments", "making sure the kids are doing their homework", "noticing that the trash needs to be taken out" and things like that can be more subtle, but are still work.  There is an emotional cost to some chores that doesn't necessarily line up with the physical labor of the task.
Look for places where you can assume responsibility yourself.  Taking out the trash, or making sure you do your homework unprompted.  By reducing the number of chores your parents need to handle, you will make it easier for them to find a balance that works between them.

Can I bring my parents back together?


Should I bring my current (updated) resume or the one I submitted for the position?

Question: I'm not sure what to do here. I got an interview in a week and this position I applied for a month ago asked me to come in for an interview. I changed the format of my resume in that time and added a few things to it. Should I just print out the one I submitted to the company? I don't want them printing out my old one and I bring my new one.
Answer: Bring the new one, and hand it to them at the start if the interview, explaining that you think the new one is more informative and easier to read. Nobody will be surprised; it is pretty much assumed that people continue to fine-tune their resumes.
Don't be surprised if they continue to base the interview on the version they have had more time to read, but if they ask a question that is civered in the new version of the resume you can mention that in the course of your answer.
Comment: … unless the two versions contradict each other at some point.  "Fine tuning" can also mean to state once that aspect X was your main interest and once that aspect Y was.  While to fine tune like this might be justified in a way and even understandable after a lengthy talk about it, it could quickly seem windy and dishonest.
Comment: Well, the one I posted listed that I still was employed with another company (which I quit a few weeks after I applied) and the old one had three employers and new one has four as I was able to fit another one in.
Comment: If you can explain the differences that briefly, is shouldn't be a problem.
Answer: Unless you think that the new changes to the resume would really improve your chances of landing the job, I would just take the version that you submitted to get the interview. That version was good enough to get you the interview and they've already studied it and may have developed some questions based on it. Throwing a whole new version at them when you sit down for the interview may not make them happy or it could throw them off - or they could just ignore it. Better to not take a chance.
That being said, if your new one has some extra stuff on it that you feel could be of use then bring one of those as well as the old one. If it comes down to "hey, we like you but you just don't seem to have enough experience with X", and you have that experience on your new resume then you could bring that out and point out that you do have that experience and you have updated your resume to reflect that.


Add an artboard between two specific artboards in Adobe Illustrator?

Question: I have 38 artboards with many objects on them. Suddenly I found out I need to add an artboard between two of exist artboards. Artboards Panel just can add artboards at the end of existing sheets, but can't add between exist them. I guess I should add an artboard, then move all artboards to the next sheet one by one, then delete unnecessary ones to get a blank one between those two specific that I want. This is an annoying, time-wasting task. what's your suggestion in this situation? If AI doens't do it, It should add this ability for the next version soon!
Answer: You can change the artboard order by clicking and dragging them in the Artboards panel. Then you can rearrange them into the correct order.
In the example below I have added an artboard shown as "1a" at the bottom. I want to move this between 1 and 2.  Note that the names of the artboards don't matter, only the order in which they appear in the Artboards panel.

Click on Window > Artboards
Click and drag the bottom artboard (9) into the 2nd position

Example:

Click on Document Setup > Edit Artboards > Rearrange All
Set the required number of columns and hit OK, and the artboards will be rearranged into the correct order.

Example:
Comment: Wow!, didn't know that cool trick to rearrange artboards. It's really time-saving technic to create and get new artboards between already created artboards. Great Job Billy!
Comment: thanks Mr. Billy Kerr, it really did worked, also it can be done with clicking menu in artboards window (stacked lines icon on top right corner on artboards window) to find "rearrange artboards" since i cant find this option in my adobe illustrator version with your method


Is it posible to install debian as host and windows as guest and use nvidia drivers in windows "normally"?

Question: i´m new in linux, but i started using debian in  vmware. Now i have windows 7, and debian as a virtual machine.
But I really liked that i can personalize a lot debian, so I decided to use definetly.
So my doubt is: Is it posible to install debian as host and windows 7 as guest in vmware and use windows "normally" ?
I mean, for example, I play some games in steam sometimes, and in windows it´s ok, but if i play games in windows as guest in vmware inside debian, can I run it witout problems? Now I use debian as guest with the noveaua driver(i was searching a few about that)
I ask that if someone already did that, I had some problems before to use my graphic card, nvidia 210, in windows 7 as host and windows 8 as guest.
If someone can tell me his experience it would be excellent. I need help in that.Thanks.
Answer: The video adapter in VMware guest OS is not nVidia, it's VMware SVGA II, so you can't install/use nVidia drivers inside guest OS (Windows).
For the question about steam, maybe you can try Steam for Linux. I can play Counter-Strike game in Fedora (although it's not as well as playing in Windows).
Comment: I will try steam for linux, I play sometimes Left 4 Dead, and in the steam page i don´t see that it´s available for linux, I don´t know how it will work in windows as guest, would it run without problems?
Comment: Left 4 Dead is available in linux: http://www.softpedia.com/reviews/games/linux/Left-4-Dead-2-for-Linux-Review-364144.shtml . I never tried playing 3D game in guest OS, because each time I start a guest OS, VMware Player will give a note: hardware graphic acceleration is not available.
Answer: Bridging a video adapter would be awesome I wonder if it's possible with some other open-source virtualisation software if not with VirtualBox.
I'd like to setup a workstation that requires a Windows-only software to run, but I'd also want to be able  to use that machines CPU and storage for other tasks when it's not needed fro the main one.


Is Egretia (EGT) is still Ethereum Token? Or It has been moved as a Coin to its own Blockchain?

Question: Currently Egretia (EGT) is represented as a Token of Ethereum Network, but is there any changes regarding shifting from Token to Coin on its own Chain?
Comment: Roadmap says "2020 Q2 - Egretia Public Chain 1.0 Release". (https://egretia.io/)
Comment: @RichardHorrocks, Public chain released, but my question is Does that means that ETG is now a Coin having its own blockchain network? or It's still a token of Ethereum network.
Answer: As noted by Richard:

Roadmap says "2020 Q2 - Egretia Public Chain 1.0 Release". (egretia.io)

This means that its own blockchain will be launched then and its own coin released. This does not, however, say anything about when the token will be migrated into the new blockchain. But it's quite probable that the migration happens immediately when the new blockchain is up and running.
In general terms creating a token is so easy and cheap quite that many projects start with issuing tokens and then later shift to using their own blockchains (if that was their intention). The shift itself is not trivial but doable:
1) Ask user his address in the new blockchain and verify his address (with whatever means) in Ethereum to see how many tokens he has
2) Assign new coins in the blockchain to his address. This should probably be done all in one initial distribution as it's typically not easy to just "mint" new coins in a blockchain.
3) Burn the user's tokens in Ethereum
Comment: Cheers Richard for the clarification. Added relevant clarification to my answer.
Comment: I think your are not getting my point that what I've asked about. My question is, that is Egretia Coin(Having own blockchain) or Token(of Ethereum)? Simple as that.
Comment: Just to reiterate and reword what me and Lauri have said: ETG is currently running on Ethereum. In the second quarter of 2020 it'll move to its own blockchain, probably using the process outlined in Lauri's answer.
Comment: @RichardHorrocks, thank you! this is the answer for which I'am looking for!
Comment: @Rudrika - Glad it helped :-) Can you mark Lauri's answer as accepted, just to keep things tidy?


Generalised eigenvalues in the residual spectrum

Question: For an operator $T$ on a Hilbert space the residual spectrum is defined as the set of complex numbers $\lambda$ for which $(T-\lambda I)^{-1}$ exists but is not densely defined. The question is: could there be a complex number in the residual spectrum which is a generalised eigenvalue? By generalised eigenvalue I mean that there exists a sequence $\{x_n\}$ of unit vectors that satisfy:
$$
(T-\lambda I)x_n \longrightarrow 0.
$$
I was thinking about this from a physics point of view (discarding the fact that observables are assumed to be self adjoint) and wondering if one wanted to make an "observable" out of something which is hermitian but doesn't have an empty residual spectrum (like momentum on $L^2(0,\infty))$ would the problem be that for such operators the system could in principle collapse to some state with a complex spectral value associated to it? This spectral value would have to be in the residual spectrum because the continuous and point spectra of hermitian operators must be real.
Comment: Note that self-adjoint operators never have resudual spectrum. And that what you call a generalized eigenvalue is usually known as an approximate eigenvalue.
Comment: yes indeed, that's precisely the source of my question, i was just trying to get a picture of why in quantum mechanics you insist that operators are self adjoint and thus have empty residual spectrum, and i was thinking that perhaps this is because if the residual spectrum is not empty, you could have complex spectral values, which is unphysical.
Comment: What you want is an operator $T$ in a Hilbert space $\mathcal H$ (may be bounded) such that $\ker T = \{0\}$ and $\operatorname{ran}T$ is neither closed nor dense in $\mathcal H$. I am pretty sure such operators exist, but I cannot give you an example right now.
Comment: Thanks! I was just trying to figure out why insisting on the empty residual spectrum is physically necessary (which is why you impose self adjoint)
Answer: Let $S : \mathcal H\to\mathcal H$ be any linear operator with non-closed range and $\ker S = \{0\}$ (for example $Sf = t\cdot f$ on $L^2(0,1)$ satisfies this). Now, let $M$ be any closed, proper infinite-dimensional subspace of $\mathcal H$ and let $V : \overline{\operatorname{ran}S}\to M$ be unitary. Then $T := VS$ satisfies the requirements.


Implications of the Riemann hypothesis in finance?

Question: I was recently at a seminar by a top hedge fund manager at a top university for finance students, when one of the finance professors asked him what do you think are important areas of research for my PhD students. The hedge fund manager responded solve the Riemann hypothesis.  My question is, what would be the implications if this were proved true?
Comment: Are you sure he was implying that it had any applications in finance? Maybe he was just suggesting that they should devote their time to studying pure math.
Answer: I think he was jokingly suggesting to breed top PhD candidates in pure mathematics. I often heard complaints that a lot of PhDs in Mathematical disciplines lack a rigorous base in pure Mathematics. Obviously the hedge fund manager was not suggesting that the proof of the hypothesis will be in any way relevant to trading or financial pricing applications. On the other side the Riemann Integral is a basic building block of discrete time stochastic calculus which is very much relevant to financial mathematics and pricing derivatives products. But I doubt he was at all thinking about the integral when he explicitly mentioned the hypothesis.
Thus, I would chalk it up as a joke and invitation to send top level candidates his way. Its funny but hard core mathematicians learn to go all the way to the basics (or are supposed to) in order to devote their time to the studies and research of entirely abstract concepts. What they UN-learn is the ability to spot the underlying currents and humor.
My friend, I suggest you are reading way too much into his comments. I would take it as a suggestion to have the professor's students focus on the core of pure Math and that he is interested in top candidates. Not more not less. Thats my take of it.
Comment: Andrew Lo at MIT typically only takes on / works with PhD students from MIT's course 6 (electrical engineering) or course 18 (Mathematics): even though he teaches and researches Finance at the MIT Sloan School of Management, to my knowledge, he is yet to co-author a paper with a Sloanie PhD. The hedge-fund guy was probably hinting along similar line, as you suggest: "I want people skilled in maths, not people who have memorized Ito's Lemma without understanding the underlying mathematics" . Ps: as a Sloanie grad myself, I am not dissing sloanies, just being honest.
Answer: Riemann Hypothesis is a very import conjecture in mathematics, but it also an extremely hard problem, top mathematicians have worked on it for over 100 years and could not solve it. Moreover, one cannot start to really think about it without proper understanding of the problem; it might take years to understand what is going on even for people with strong math background.  Therefore, if someone is telling you to solve Riemann Hypothesis they can't be seriously suggesting you to work on it.
As Freddy and user2303 suggested, it could've been a hint to work on math skills. Or maybe he was hinting at that the research is really not that important, "It doesn't matter what you work on".
I wasn't there and I did not feel the mood of the seminar, but I am sure the manager did not suggest students to go after the Riemann Hypothesis!
Answer: A number of economic theorems relevant for large financial institutions depend on the truth of the Riemann Hypothesis. They include things like uniqueness results of mixed-strategy game theory equilibria, demonstration that various policies converge and are therefore (eventually) equivalent along some axes, and limiting the potential downside of classes of investment or policy.
The practical policies that depend on RH being true are obviously not going to be massively affected (unless it's proven false), but the policy-choosers will gain substantial peace of mind from upgrading their assumption to a certainty.
Answer: The humor aspect alluded to by Matt Wolf and user2303 certainly makes sense: in that vein, since the Riemann hypothesis is one of the unsolved "Millennium" math problems for which there's a monetary award (apparently of USD 1mm) I can certainly see a HF manager's angle on it. Though why he chose that particular problem rather than, say, the Hodge Conjecture, is elusive - perhaps he has an affinity for number theory over geometry!