How can I remove ants from my laptop keyboard?

Question: There are ants in my laptop keyboard again. It's happened before and ended up killing my productivity occasionally as the little critters suddenly show up from within the gaps of the keyboard. I had to bring it over to my uncle and he got rid of the ants, somehow, but I forgot to ask how he did it.
How can I get rid of them?!
I've seen this post on Electronics.SE but it got closed, so it didn't get any helpful answers even in the comments.
Comment: You just need to ... "debug" it (sorry, couldn't resist).
Comment: stop eating near your laptop. it will work. ants don't go where there isn't food.
Comment: What is this......... a keyboard for ants!??
Comment: related [What's the best way to get ants out of laptop keyboards?](http://superuser.com/q/256692/172747)
Comment: It's an ASUS-ul20ft, if it helps. Also, I'm not positive on disassembling the laptop to a point where it's easy to clean, since I've tried reassembling three laptops and none of them have ever worked since.
Comment: @BobJarvis only the keyboard though. You don't want to risk condensation on other parts of the notebook if you can avoid it.
Comment: You know what would make this question even better? Photographs.
Comment: This really should have been on http://superuser.com/. LH seems to be randomly sucking good questions from other sites lately, especially SU and Cooking. In any case, the existing SU question is easy enough to find, downvoted due to lack of research effort.
Comment: Try putting your laptop in the freezer for a few days.
Comment: Stop **eating** on your laptop, for goodness sake!
Comment: Find some anteater (http://en.wikipedia.org/wiki/Anteater), of course...
Comment: @Unihedron who's screaming and running away? The ants?
Comment: @BobJarvis — I'm pretty sure, when you take it back out, you'll just have colder ants. Most insects do pretty well with freezing, and thaw out just fine afterwards.
Comment: @IQAndreas I'm not sure how you'd expect me to _take a photo_ when I see ants in my keyboard over screaming and running away, but sure, I'll take a picture if they appear again. I've adopted and attempted some of the solutions in the answers and they're mitigating the problems rather well though.
Comment: What is this, lifehacks for ants?
Comment: @corsiKa I'd like _you_ to say that when it's _you_ who has ants in their keyboard. >:|
Comment: Ants may nest in a laptop even if there is not food that attracts them to it. This solution has worked for many people: http://fertileforest.hubpages.com/hub/Getting-rid-of-laptop-ants
Answer: There are already some good answers for how to get them out immediately. However, I have an alternate proposal: Wait until they leave on their own.
They're there because there's food in there. As others have suggested, this is probably food or drink from your meals. If you let them work, they'll clean it for you by removing every trace of food. Once it's clean, they'll leave. They're not likely to build a nest in there or anything and they shouldn't be able to get down into any sensitive circuitry and get fried.
Pop out the battery. Find where they're getting inside. Put the laptop next to the opening. Wait until they're done. Keep food and drink some reasonable distance away from the keyboard.

This is especially effective if you've spilled a sugary drink on the keyboard. They can get rid of all the stickiness.
Comment: So, if I spill something sugary on my keyboard in the future, I can just place it next to an anthill and it will be cleaned? Sounds awesome! This is probably even faster than disassembling the whole keyboard and cleaning the usual way.
Comment: +1 for thinking outside the box. I've got a keyboard around here with a sticky control key (stays down when pressed). I should go find an anthill..... ;-)
Comment: It's how they clean bones at the Natural History Museum; after cutting off most of the meat, they leave the bones in a tank with beetles, and after a few weeks, they take them back out again, with all the flesh gone.
Comment: @mc0e I'm speaking from an antkeeper's perspective. In order to set up a nest ants need not only an appropriate temperature, but most importantly - areas with varying humidity. In the nest there have to be some places where moisture is high so they can keep their eggs and larvae. There is no way that they find these conditions inside a working laptop.
Comment: If they can tolerate the temperature of the laptop while running, then they may be qute happy with using it as a nest, while foraging elsewhere for food.
Comment: @BuahahaXD I've seen ants nest in a dry coke can under cover.  That was in a relatively cool and damp climate though.  Perhaps the limiting factors on where ants will nest vary with climate and species?
Comment: @mc0e Have you seen them keeping the eggs and larvae there? Have you seen the queen?
Comment: @BuahahaXD In the coke can, yes.  The ants are out of my laptop now, though I'm still working on getting them out of the monitor stand which has no sign of eggs.
Comment: Actually it was only the live ones that were out of my laptop.  Thousands of dead.
Comment: Always use [Naphthalene](https://www.google.com/search?q=napthalene+balls&ie=&oe=) balls in your laptop Bags. This will avoid bringing any creepy insects and pests
Answer: To remove almost anything, the simplest and most effective way is to use an Aero Duster. These blast compressed air in under the keys and into all the nooks and crannies and will safely leave your keyboard ant-free.
Of more importance is how to avoid ants deciding to colonise your laptop in the first place. You must have spilled something sweet in there at some point, so you may wish to avoid bringing food and drink anywhere near it.
If it is still attractive to ants, you can always pop it apart - all laptops are fairly easy to disassemble, as long as you know where the clips and screws are - and as all laptops are different, I'd suggest looking for a youtube video showing your particular one.
Additionally, when it isn't in use, put it back in a laptop bag. It will help.
Comment: *Dis*assembling the laptop never was the problem. It's putting the damned thing back together that gets me.
Comment: `"[...]all laptops are fairly easy to disassemble[...]"` --> try disassembling a 10 years old Toshiba or a 4 years old Sony Vaio.
Comment: @corsiKa Putting it back together's not the problem for me. It's the leftover screws that's the problem :P *note to self: take more photos*
Comment: _"all laptops are fairly easy to disassemble..."_ - https://twitter.com/Kirtaner/status/589164738870960128
Comment: I had to take one apart yesterday. And I only evaluated my life 400 times. It was a really old Toshiba. It was around 80 screws, 10 plastic bits, the screen and a tonload of parts everywhere and cables to connect. I tested it 5 times to be sure. The more recent Toshibas are also a little harder than 4 years old ones. But the worst, are the Sony Vaio!
Comment: Yep - admittedly I had already been disassembling laptops for >10 years by that point so had had practice
Comment: time consuming, but very straightforward and simple to do.
Comment: FWIW with Lenovo W540, at least, be very careful, it's very easy to pop keys off when attempting to open the keyboard
Answer: I am from India. We have good sunlight almost year-round. If I were you, then I would simply put my laptop in the sunlight for 5-10 minutes. The ants will leave the keyboard because it will get too hot for them. Be careful with a plasma display - sunlight will harm it!
Comment: I would expect the whole thing to heat up relatively fast in direct sun light in a country like India. So it would get too hot for the ants and they would leave.
Comment: Welcome to Lifehacks.SE! Could you please explain further why sunlight keeps away ants?
Comment: @basher >Gonna need a source on it being hot in India.  Srsly?  The [roads are melting](http://www.theguardian.com/world/2015/may/28/indias-deadly-heatwave-set-to-continue) at the moment
Comment: holroy: It shouldn't be an issue. Heat generally is fairly fine for all computer parts up to somewhere >50C (ie >120F). What will cause a problems is if using it and the surface is at 50C, leading the CPU temp inside becoming >100C, leading to it crashing. Even then, odds are it will crash-out and shutdown without damage.
Putting a computer in the sun, with it shut down should be no issue.
---
There are 3 parts you have to worry about: Melting solder (Unlikely), Vaporising electrolytic capacitors, and I think most likely: Warping the Plastic Case.
Comment: Heat is not good for battery life, so take that out too
Comment: I'm not sure how healthy this is for your computer, though. You could end up harming the computer due to overheating.
Comment: `Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.` Gonna need a source on it being hot in India. I don't buy it, and neither does SE.
Comment: @mcalex I guess you're not very familiar with sarcasm? All the answers here are using personal experience as a reference, but this post is singled out as requiring additional references. I too wonder why that is.
Comment: Yes this answer easy anmong the others.. Because Ants cant tolerate high heat
Comment: I have no idea how this works , but I've been doing this for various things from containers to raw food items.
Comment: @nafg Agree that heat is not good for battery life. So you can remove the battery & then put laptop in sun light. & BTW I advised to put laptop in sun light for 5-10 minutes only. I dont think this is too much time that battery or laptop will become that much hot.
Comment: I've got a Lenovo X220.  I probably don't need the sun to heat it up, I just turned the laptop on and the ants came streaming out.  But after half an hour they're still coming out.
Comment: What I do is play a game for an hour or so to kick off the heat and fans to drive away the ants. but if I shutdown the laptop, they're back. So now I just keep it running.
Answer: One way is to lure them out with something sweet and then not let them go back inside the keyboard.
Another is to suck them out with a vacuum cleaner or blow them away with a vacuum cleaner on reverse. Don't forget to take out your keyboard from the notebook to avoid blowing something unwanted inside.
Also you might want to try freezing them. Don't attach the keyboard back too soon after taking it out of the freezer though to avoid short circuiting due to possible condensation due to temperature difference.
Extreme solution: put your notebook in a sealed container, vacuum air out and insert a deadly gas >:) One easy gas is butane from a regular lighter.

Put the keyboard inside a plastic bag where you can see what's going on inside and have good control of the lighter.
Suck the air out with your mouth, it should not be dangerous unless your keyboard already contains deadly gases or you tried bug poison earlier. In that case use a vacuum cleaner hose.
Press the lighter button, but don't light it, obviously. Let out enough gas so that the plastic bag inflates visibly, and the proportion of the air to gas is small enough to seem deadly for the ants.
Leave for a day to be sure, but in a place where kids, fire and direct sunlight can't reach it. Or it could result in a noticeable explosion. Better put the plastic bag inside a more protective container, like a jar, in case ants decide to run for their lives and eat through the plastic bag, resulting in a leak.
After you're sure the ants are dead, let out the gas inside the bag in conditions that would not result in gas explosion. The ants inside are probably not holding onto anything, so you can shake them out of the keyboard and plug it back in.

Simply vacuuming air out may not be effective because the ants are pretty small and who knows how long it would take for them to breathe through all the oxygen between the keys and the keyboard base. Saturating their air with a non-breathable gas should speed up the process sufficiently.
Comment: Do you have some kind of dark Nazi past? That evil smiley scared me...
Comment: Remove the battery before attempting this so that there won't be a follow up question of "How do I get charred ants out of my laptop?"
Comment: I can imagine small fire blasts coming from beneath the keyboard keys as you later run some demanding programs on the laptop which causes it to overheat.
Comment: Umm, I'm talking about keyboard removed from the rest of the notebook exclusively, and there is no step involving prolonged high temperature treatment of the keyboard. There should not be any charred ants if you follow this procedure.
Answer: Cut off their air/water/food, and they'll die. Just put your laptop in a sealed plastic bag for a couple days. A 2-gallon Ziploc freezer bag should do the trick.

*This only works if you can go without a computer for that long.
Comment: But then the OP will be posting "How can I remove dead ants from my laptop keyboard?" soon.
Comment: Hahaha true! That compressed-air canister idea will probably do the trick.
Comment: Even without doing this, I have so many dead ants under my keys that some of them are failing to work, and I'm having to take the caps off to clean them out properly.  I just removed 30 or so ant bodies from under the enter key.  There's no way compressed air could get them out from inside the hinge.
Answer: I just read in Consumer Reports that ants hate cinnamon. Maybe a sprinkle of it would help. I have to agree with the other commenters though that making sure that you're not putting food in your keyboard is the best option. I know that you can buy plastic keyboard covers for just that purpose.
Comment: Can you link the writing?
Comment: [This reports success](http://theparsimoniousprincess.blogspot.nl/2012/05/ants-hate-cinnamon.html), the [theory](http://www.ehow.com/how_2310653_get-rid-ants-cinnamon.html) being that ants avoid stuff that interferes with their smell trails. I simply put two copper coins near my front door to stop ants from wandering inside.
Answer: My wife discovered something that most ants loathe and detest. They will go to any lengths to avoid it and escape it. They will not go near it.
All you do is put a TINY amount on, in, or near any thing or area where ants are and… They're gone.
She first noticed its effect on tiny black ants in a bathroom and then with tiny pharaoh ants.
What is this magic ant repellant? CHANEL™ Body Powder.
Try a pinch on a sheet of facial tissue and put in in a plastic bag to coat the tissue lightly and evenly. You do not need much. After all, how much body powder does a tiny insect need for their tiny antibodies.
Put your infested piece on the tissue or lay the tissue on the keyboard. The ants will find their way out of any ports on the sides. Otherwise cover half of the keyboard so they can escape from the other side.
After the ants vacate the premises, the residue will keep the place void of them.
I'd love to watch. Good luck.
Comment: Now I wonder what the Chanel marketing people will do when they discover this post ;-)
Answer: Wash your keyboard in the top rack of an automatic dishwasher. I do not recommend using dish washing liquid...many have bleach in them that will lighten some of the color of the keyboard plastic. Also, don't use a cycle that dries with high heat. Let the keyboard dry completely before using.
Answer: Diatomaceous earth. It is used in pest control, because it is actually comprised of tons of tiny edges, small enough that it does not hurt your (relatively) very thick skin, but will grate on insect exoskeletons, causing them to dry out.
Sources? Try google. There are many articles about how to use DE as pest control. In addition, you can sprinkle it on your garden (if you have one) to keep bugs away.
Comment: Let me understand this, you are adding sharp grains into your keyboard where they will destroy the contacts and jam the key mechanisms?
Comment: I did not think this through, now that I really think about it, no, don't do this. should I delete this completely or edit to remove the 'use it here" part and keep it here as it is vaguely relevant?
Answer: Usually Boric powder works when trying to get rid of ants.
But using it on laptop keyboard I am not sure. But probably safer than bug sprays. (Make sure laptop is switched off and battery removed).
You can bait them out by placing some sweet/sugar stuff on your laptop trackpad.
And smash to kill as they come out.
p.s. avoid eating or keeping food items near your laptop to avoid future infestation.
Comment: DO NOT put boric acid on anything you'll be touching! This is a *contact poison*! Ditto and likewise for any other insecticide!
Comment: I wouldn't suggest killing them when they are inside keyboard... They might be in some place that's not easy to take out.


Trump's use of "our" when "the" would do

Question: Mr. Trump and his spokesperson seem to favor the word OUR, as in our great military or our nation when THE nation might do. Is there a signal or purpose for this usage?
Comment: It's sort of a variation on "the royal we".  Used for political purposes, to evoke patriotic fervor.
Comment: **MODERATOR NOTE: Do *not* answer in comments**. Answers in comments may be removed.
Comment: He is attempting to revive patriotism, remind citizens that their voices should be reflected in legislation, generate support for our troops, and generally make Americans feel like part of the same team. (I ain't saying it's going to work - but *our*, instead of *the*, is not arbitrary.)
Answer: With regard to inclusiveness, Winston Churchill did much the same seventeen days after taking over as Prime Minister on the 10th of May, 1940 (eight months after the beginning of the Second World War) when he made a brief statement to the Commons on 28 May reporting the Belgian capitulation, and concluding:

Meanwhile, the House should prepare itself for hard and heavy tidings. I have only to add that nothing which may happen in this battle can in any way relieve us of our duty to defend the world cause to which we have vowed ourselves; nor should it destroy our confidence in our power to make our way, as on former occasions in our history, through disaster and through grief to the ultimate defeat of our enemies.

Having spoken to the House of Commons, thus, and having assumed their unity of purpose he then included not only the people of Great Britain but the nations which (at that time) encircled the globe in Commonwealth:

We shall go on to the end. We shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender [...].

Then, including the 'Empire' and also the 'New World' - meaning the USA in particular - he continued:

and if, which I do not for a moment believe, this island or a large part of it were subjugated and starving, then our Empire beyond the seas, armed and guarded by the British Fleet, would carry on the struggle, until, in God's good time, the New World, with all its power and might, steps forth to the rescue and the liberation of the old.

Wikipedia

You ask 'is there a signal or purpose' to the present inclusiveness expressed by POTUS ? And that is why I have quoted Winston Churchill at length for the world faces a far more destructive force now than it did in 1939-45.
Now, by using technology that has become all too accessible, a rogue state  threatens the entire globe and attempts to push the whole of humanity towards an unthinkable precipice, while those closest to it seem reluctant to repress such ambitions.
And its solicitations regarding Olympic Games could as well be an attempt to drive a wedge between the whole peninsula and the rest of the world, or as well be a mere truculent response to sanctions, than they might be a genuine step towards a better peace.
I think that the President of the United States (whoever that happens to be at the present time) is quite right to attempt to gather the USA into one and is quite right to seek international allies in order to maintain the balance of power in this most dangerous world in which we live.
Comment: Uh, it's _whoever._
Answer: He is being precise.
There are in fact many great militaries, and many nations in the world, and while from context it is unlikely that Trump is referring to any other than the US, he is more technically clear in saying "our" rather than "the". Especially if you realize that some of Trump's listeners are international. Reminding people that they are part of the nation never hurt a politician either.


light gravitational wave interaction

Question: What happens when light photos and gravitation waves collide?  Like can the photon "surf" on the gravitational wave and change direction, wavelength, velocity?
Answer: Light follows geodesics and gravity waves modifies spaces thus geodesics, so the light should be slightly deflected (but it will be the opposite way at opposed phase. This might still cause an offset, as for refraction through a  a glass sheet). Note that both travel at the same speed, so interaction can only occurs for different directions of propagation.

light gravitational wave interaction


Is $(p^2-1)/2$ never squarefull when $p > 3$ is a Mersenne prime?

Question: Let $p\neq 3$ be a Mersenne prime. Is it true that $(p^2-1)/2$ has a prime divisor $r$ such that $r^{2}$ does not divide $n$?
Comment: The condition "for every prime $q$ dividing $n$, $q^2$ also divides $n$" is called being powerful in the literature. So after dividing out the factors of $2$, you'd like to know if $2^{p-1} - 1$ is ever powerful when $2^p - 1$ is prime. Ribenboim has some conjectures related to similar questions in "The New Book Of Prime Number Records", in the section on Wieferich primes.
Answer: Well, maybe I'm missing the point, but the first Mersenne prime is $3=2^2-1$, and $\frac{3^2-1}{2} = 4 = 2^2$, so... no, I guess.
Answer: Considering there are only 47 known Mersenne primes, and finding the factors of $2^p-1$ is a difficult task, I'm not sure this question is fully tractable.
But we can certainly show that all of the known Mersenne primes satisfy your question. First, take $m=2^p-1$ to be a Mersenne number, and rewrite $n= \frac{m^2 - 1}{2} = 2^{2p-1} - 2^p$. This is powerful when $p=2$, which gives Philip van Reeuwijk's counterexample. For larger $p$, we know $4$ will always divide $n$, so we can ignore powers of $2$ and just consider the odd part $n'= 2^{p-1} - 1$.
We know $p$ is prime, and odd since it is not $2$, so we are looking at $n' = 4^k - 1$, with $k=\frac{p-1}{2}$. Clearly $3$ divides $n'$, and $9$ divides iff $3$ divides $k$. So we require that $p \equiv 1 \mod6$. This is not enough; plenty of known Mersenne primes have this property.
Since $3$ divides $k$, we can write $n'=64^{k'}-1$. Then $7$ divides $n'$, and $7^2$ divides $n'$ iff $7$ divides $k'$. So now we require that $p \equiv 1 \mod42$. Sadly, again this is not enough.
One step further, we see that when $7$ divides $k'$, $43$ divides $64^{k'}-1$, and $43^2$ divides iff $43$ divides $k'$. Now we're happy (for the time being), because no known Mersenne prime has $p\equiv 1 \mod 1806 = 43*7*6$. But it seems there's no reason they can't have this property, so you may have to continue your search once such a Mersenne prime is found. Expect one by the 504th instance: $504 = \phi(1806)$.
Comment: I have checked a few cases, and if $m = 2^p-1$, it actually seems the case that $p$ is a factor of $n = \frac{m^2-1}{2}$ and $p^2$ isn't. This even seems to work when $m$ isn't a prime but just the $p$-th Mersenne number with $p$ prime. I can't prove it, though...
Comment: If you could that would be something interesting. Showing that $p$ divides is an application of little Fermat. Conjecture $W'_2$ on $p. 343$ of Ribenboim's "New Book of Prime Numbers" is "There exist only finitely many primes with $2^{p-1} \equiv 1 \mod p^2$", and he goes on to show that this would imply solutions to other well-known open problems.
Comment: Yes, the little Fermat part I had figured out already; the part about $p^2$ not being a factor is beyond me, I fear. Ribenboim's book looks interesting, I'll check it out. Thanks for the tip!
Comment: Just to clarify, such primes are called Wieferich, and only two are known: 1093, and 3511.


BPEL for data synchronization

Question: I am trying to use Oracle SOA BPEL to synch data of about 1000 employees between an HR service and our local db.  I get IDs of all employees with a findEmp call and loop through it empCount times to getEmp(empID) from the same HR service and update/insert into our db in every loop.  This times out after about 60 odd employees, though this process is an asynch process.  How should I redesign the process flow?
Comment: I created a process that calls findEmp and another that synch a single emp using getEmp(id).  I invoked one-way calls to the latter in a loop, no more timeouts.
Answer: The timeout is occuring because you don't have any dehydration points in your BPEL code. Oracle BPEL needs to dehydrate before the Java transaction times out.
If you are using the Oracle BPEL DB Adapter, you can actually submit many objects at once for processing to the database, simply put more than one in the  element from the DB Adapter. This may help a lot, since you can fetch all your data at once, then write it all at once.
Additionally, you can extend the transaction timeout for Oracle BPEL- it's a configuration parameter in transaction-manager.xml (there's also some tweaks to the EJB timeouts you need to do on 10.1.3.3.x & 10.1.3.4.x). The Oracle BPEL docs tell you how to change this variable.

BPEL for data synchronization


splitting field for a finite dimensional central simple F-algebra$A$

Question: Definition : Let $A$ be an $F$-algebra and let $K$ be an extension field of $F$. The $K$-algebra $K \otimes_F A$  is called the scalar extension of $A$ to
$K$. It will be denoted by $A_K$.
Definition :Let $A$ be a finite dimensional central simple F-algebra. An extension field $K$ of $F$ is said to be a splitting field for $A$ if $A_K \cong M_n(K)$ for some $n \in N$.
Corollary : Let $A$ be a finite dimensional central simple algebra. If $S$ is a subalgebra of $A$ that contains the unity of $A$, then $C_A (S) \otimes A^{o } \cong End _S (A)$.

Theorem : Let $D$ be a finite dimensional central division algebra. Every maximal subfield $K$ of $D$ is a splitting field for $D$.
Proof: If $a \in C_D(K)$, then $a$ and $K$ generate a field. Therefore $a \in K$ since $K$ is maximal. That is, $C_D(K) = K$. Similarly, $C_{D^{o}} (K) = K$. According corolly, therefore shows that $K \otimes_{F} D$ and $End _K (D^{o})$ are isomorphic as F-algebras. Since $D^{o}$ is finite dimensional over $K$, we have $End K (D^{o})\cong M_n(K)$.

so, my questions :
1: In theorem, why is $K(a)$ a field?
2: why $C_D(K) = K$and  $C_{D^{o}} (K) = K$?
3: why $End K (D^{o})\cong M_n(K)$ ?
Answer: I.
Recall what a field is: a field is an abelian group (addition) with a multiplication such that the field minus $0$ forms an abelian group, and satisfies some axioms like the distributivity.
Now $K(a)$ with addition is obviously an abelian group. Since $a$ commutes with $K$, $K(a)^\times$ with multiplication is also an abelian group. The conclusion follows.
II.
$C_D(K)$ already contains $K$ as $K$ is a field. The above shows that $C_D(K)\subseteq K$. Similarly for $C_{D^o}(K)$.
III.
By the corollary (take $A=D^o$ and $S=K$), $K\otimes_FD\cong End_K(D^o)$.
But what is $End_K(D^o)$? It consists of $K$-linear endomorphisms on $D^o$. If $D^o$ has dimension $n$ over $K$, then this is nothing other than $M_n(K)$.

Hope this answers your question.


Set Blob cache to false

Question: what is the use of blob cache?
Is it supported to set the blob cache to true or false

what's the effect of set it to true
what's the effect of set it to false
Answer: What is the use of blob cache?
The BLOB cache is Disk-based Caching for Binary Large Objects.
it stores copies of binary large object files that are used by web pages, such as images and CSS files on the file system of WFE servers.
This enables SharePoint to serve these files more quickly because the WFE server no longer needs to retrieve the file from the database.
Is it supported to set the blob cache to true or false
Yes, I didn't find any frank article says it's not supported. but in some cases, it's not recommended to be enabled! so it's disabled by default!

Note:
it's highly recommended to disable the blob cache during the dev and design phase!

What's the effect of setting it to true
Enabling the blob cache will improve the performance of your sites and reduce the load on your database servers because at the first time that a web page is called, these files are copied from the database to the cache on the server hard disk drive, and all subsequent requests for those files are then served from the hard disk drive cache of the server

Note: after setting the blob cache to true, you should perform

IIS Reset.
Open the site settings instead of the homepage.

Note:

The BLOB cache will increase disk I/O on your WFE servers. meanwhile, it will decrease the load on the database and network!

What's the effect of setting it to false
The Binary Large Objects files will not be cached!
For more details check

Blob Cache in SharePoint
Introduction to BLOB Caching in SharePoint
Cache settings operations in SharePoint Server
Answer: The disk-based BLOB cache controls the caching for binary large objects (BLOBs), such as frequently used image, audio, and video files, and other files that are used to display web pages, such as .css and .js files.
The BLOB cache is enabled on a front-end web server and improves performance by retrieving BLOB files from the database and storing them in a directory on the front-end web end server where they are served to users. This reduces the network traffic to and load on the database server.
You can read more information about the blob cache, here.
To configure cache settings, check this link.

Set Blob cache to false


When I stretch a rubber band, it breaks. When I hold the broken ends together, why doesn't it join again?

Question: The question is simple. When we join the two broken surfaces, what is it that keeps the surfaces from connecting with each other, while earlier they were attached to each other? Also, would the two sides join again if I hold them together for an infinite amount of time?
Comment: @afro54 What basis do you have for assuming that the questioner is at the level of understanding that your objections are meaningful to them, or would have occurred to them had they given further thought?  (I for one would like to know the answer to this one, and know nothing about the material physics necessary to start figuring it out myself.)
Comment: I feel like some blend of a chemist and material scientist would be able to give a good answer.
Comment: This might not be possible with rubber, but can be done with some soft metals and its called [cold pressure welding](http://www.coldpressurewelding.com/cms/index.php?option=com_content&view=article&id=92&Itemid=2). A similar process that also adds ultrasonic energy is often used to connect the tiny gold or aluminum bond-wires between silicon chips and their leadframe packages.
Comment: Why is anybody even answering this question? What basis does the questioner have for seeking/assuming any of the properties that he fails to find in a rubber band? As in, why should it join together again? As in, a solid has low-cohesive bonds, that do little to mingle when two bodies are conjoined. The cohesive bonds of a liquid mean that two bodies of that liquid will merge, when conjoined.
Comment: Same reason that broken pieces of eggshell don't fuse back together if you reassemble the broken egg.
Comment: @tparker actually, when i asked this question few years ago, the source of intermolecular forces was a mystery to me, and it still is. But now i know that the explanation is Quantum mechanical, and also complicated, but when i asked this question, i remember also considering gravity as a possible candidate. So, i was quite lost back then.
Answer: You are thinking of a lego or a jigsaw puzzle. You have to think of huge numbers and tiny dimensions . There are $10^{23}$ molecules in a mole. The atomic dimensions are less than $10^{-9}$ meters. The lattice that has been broken will not fit the puzzle if it has been moved further than this last small distance because the molecular forces will not match. In addition the break will have displaced the locations of atoms and molecules on the two sides, in this microscopic distance making fusion even more improbable.
Comment: You would fall into the HEP ( heisenberg uncertainty principle) with your rubber band. Nanotechnology may reach that stage at some point since they are already manipulating atomic levels, but not your rubber band. The dislocations created by the break cannot be manipulated like lego, i.e. put back in their original molecular position in random material breaks. Melting and soldering is not the same as putting the ends together and expecting a fusion.
Comment: What if we take a microscopic care in matching the two ends?
Comment: What is "foundation and Empire"? A movie?
Comment: It is a saga, science fiction by Asimov http://en.wikipedia.org/wiki/Foundation_and_Empire
Comment: See [cold welding](http://en.wikipedia.org/wiki/Cold_welding)
Comment: But consider the Johanson Blocks created w/ an atomic blaster in "Foundation and Empire" :-).
Comment: very good answer. +1. Just one question though. As you say it is thermodynamically improbable. Is it possible though?
Comment: @Gareth yes, but note "vacuum" and very "flat surface" which does not apply to a broken rubber band.
Comment: @Sabyasachi From what he said, I'd think that it is theoretically possible. It is also possible, under what I understand of quantum physics, that you will disappear suddenly and reappear on Mars today. Both are very, very, very improbable events, though.
Comment: @Schilcote [Not as improbable](http://what-if.xkcd.com/53) as you [might think](https://what-if.xkcd.com/54)
Answer: First of all you need to understand how the rubber is held together in the first place. Rubber, plastics, carbon fibre and pretty much all forms of living tissue are held together in the same manner. All, or a large part of the molecules are long strings, either repeating the same simple pattern, or a number of slightly different patterns organised in random order. In some cases the strings are several thousand atoms in length. When the strings are packed tightly together they attract one another, thus they end up sticking together, and because of the interlaced structure the combined strength is much larger than this attraction between two  flat surfaces would be.
If you pull hard enough to break such a structure one or a combination of two things will happen:

The molecules slip out of their interlocked configuration, this leaves holes in both halves of the object where the molecules now belonging to the other half used to be, there is vacuum in these holes so they collapse almost instantly, all the lose threads of the broken ends fall towards the object and the majority of those surfaces where the two halfs were attracted end up attracting surfaces from the same half. Thus there is no room for the connections that used to be to be reformed. If you stick the two ends back together you can only hope to form a connection along the break surface, which will be much weaker as it lacks the interleaving, and even this is often impossible as air between the two objects prevent them from joining.
The molecules break. When you break a molecule through sheer force the resulting two molecules will typically be radicals. These radicals will react rapidly with other molecules, especially other radicals, so the broken ends will typically end up either binding to one another, or snatching some atoms from the air in order to patch the hole and stop being radicals. In either case this leaves the broken ends in a state where they will not simply rebond with their old counterpart.

Rubber in particular is a material that takes long to settle, the molecules of a common rubber band are slowly shifting positions, making and breaking bonds between molecules. This means that it is actually possible for some rubber bands to rejoin given time (or become a big clump in the pack), pressure or heat may speed up the process. Unfortunately this shifting also in general makes the rubber weaker with time, if it has shifted enough to rejoin it has probably also shifted enough to be uselessly weak.
Comment: The clump in the pack comment does explain a lot!
Answer: Your question is perfectly valid despite most people may think it's odd as reason looks obvious.
There's a property of system called entropy which must not decrease for any process (do some research on web; You may have problem in understanding it as you're in high school). Only those processes in the universe happen in which entropy of system either stays same or increases. For all real-world processes, entropy increases (stays same thing is for ideal reversible processes).
When you touch something hot, heat is transferred from that object to your body. You can argue about that: "Why not opposite?" Your argument would be valid as energy conservation law wouldn't be violated even if heat transfers from your body to that hot object. You can do such argument on almost all real life processes.
In case of your broken rubber band, it won't be attached again to become as before even if you try to undo all energy changes you did at molecular level (holding pieces together is also such try).
The key to all is entropy change. So, the answer to your question: The rubber band won't be attached again automatically because entropy of system would be decreased by that.
And, don't underestimate entropy thing. It is discussed in high-level theories like string theory, QFT. Entropy change is sometimes called "arrow of time".
Comment: Yes, probability of getting a disordered arrangement is more than getting an ordered arrangement in the case of rubber bands... maybe that is why.
Answer: Many of the proposed answers focus on entropy and the low probability of all the microscopic components of the process coming together to result in a reformed band.  I'm not convinced these answers get to the second part of your question: given infinite time will the band be reformed?  Before coming to my approach to answering your question, a brief look at rubber.
Some chemistry
Let's assume that the rubber band is made out of natural rubber, which is a polymer of isoprene with some impurities in it.  We'll ignore the impurities.  The isoprene polymer, or polyisoprene, looks like this:

These long chains (n is easily > 10^4) can slip and slide across one another, and without any stability make for a really crappy material for holding things together (a chewed piece of gum molded into the shape of a band would have better elastic and stability properties).  To add stability and elasticity to natural rubber, the polymers are crosslinked through vulcanization.  Sulfur is added and makes bridges between neighboring polymers, allowing them to move but not get too far away.  The crosslinked polymers look something like this, although note that the actual material wouldn't have as high of a sulfur density as depicted in this figure

Some reactions
Let's walk through your thought experiment.  When the rubber band is stretched to the point of breaking, chemical bonds are broken.  Looking at the cross-linked image above, the options are S-S bonds, S-C bonds and C-C or C=C bonds.  Looking at the bond dissociation enthalpies we see that the S-S and S-C bonds are the weakest of the set; so in all likely hood, the bonds that are being broken are the bonds added through the vulcanization/cross-linking process.
In an oversimplified picture, we can express rubber band breaking like this:
$$formed\ band \rightleftharpoons broken\ band \\
 S-C \rightleftharpoons S\cdot +\ C\cdot$$
I use double arrows here because in your thought experiment, we are assuming that the band breaking is a reversible processes.  Given that bond breaking requires energy, it stands to reason that your conjecture has some merit; namely, bond formation is energetically feasible and given enough time should occur, resulting in a reformed band.
Some thermodynamics
Chemical reactions can occur under thermodynamic or kinetic control.  I interpret your statement "...given infinite time..." as what is the product of this reaction under thermodynamic control?.  We therefore need to look at the Gibbs free energy of the bond dissociation reaction to determine the thermodynamically favored products ($S\cdot + C\cdot$ vs. $S-C$, or broken band vs. whole band).  For a thermodynamically favorable process,  $\Delta G = \Delta H - T\Delta S$, $\Delta G$ must be negative.  For bond breaking, $\Delta H$ is positive and $\Delta S$ is positive, meaning that $\Delta G$ is negative when $T \Delta S$ is greater than $\Delta H$.  We can therefore claim that there is a temperature at which breaking of the rubber band is thermodynamically favorable.  Intuitively this makes sense: heat up the rubber band, eventually it will no longer be a rubber band.  Since we are interested in the reverse reaction, we change the signs of the thermodynamic properties and bond formation (band repairing) would be thermodynamically favorable at low temperatures (although that low temp may have to be very close to absolute zero at which point chemistry starts getting weird).
Conclusion
So I think the key to this question is your use of the term infinite, which moves us from a kinetic regime to a thermodynamic regime.  I'm also making some pretty hefty assumptions (e.g. approximating band breaking/forming with a single type of bond breaking/forming) which may be too broad. Under these constraints, the thermodynamics suggest that a formed band is more favorable than a broken band.  If my model is overly simplified, you can use the same process with more conservative assumptions.
In reality, these type of thermodynamic thought experiments aren't terribly helpful.  Diamond, for example, is more thermodynamically stable than graphite.  I'm not going to win over the girl-next door by giving her pencil and saying, "my love for you is as eternal as this diamond will be".  As soon as you move back into the realm of finite time, kinetic control is going to take over, and the energy barriers to rubber-band formation are going to be too high for the repair to happen.
Answer: You have broken the chemical bonds between the molecules by inserting energy which is then dissipated. You also distorted the molecule structure. To repair this you should again insert energy. Holding the pieces together does not provide the energy, nor reorders the molecule structure.
The answer to your second question is this no.
Comment: What you say about energy sounds true, because if we heat the two ends and then join them, then the bond will be made. But i think that if you hold the two ends together for infinitely long time, molecules might intermingle eventually... What do you think about this?
Comment: Only in an Infinite universe.
Comment: I have seen some old mud houses that the inhabitants claim have sunk a little into earth with time. It is, i think, example for intermingling of particles of the house and the earth with time... Does that suggests anything?
Comment: Completely different molecule structure. Mud is more liquid.
Comment: Maybe time can compensate the difference between nature of mud and other material. eg. more rigid bodies would take longer, water would take only seconds to intermingle...
Comment: The answer is no. There is a minimal energy needed to restore the molecular bonds. Prolonging the time does not take you over this 'threshold'.
Answer: Exact mechanism varies with material. Simple materials (non-organic) are easier to analyze.
Simplest answer is if you bring them together they will join, provided size is small.
For example in Cold Welding less than 10 nm wire is rejoined just by contact. The exact mechanics depends on what kind of Intermolecular force is in play.
According to Grove Karl Gilbert

To my mind it appears that the difference is only imaginary and not
  real. Rigidity and plasticity are not absolute terms but relative, and
  all solids are in fact both rigid and plastic. The apparent contrast
  between the two properties belongs to the laboratory and to those
  phenomena of nature involving small masses and small forces. When
  great masses and great forces are involved, as for example in the
  making of continents and mountain chains, the distinction loses value.
  The phenomena of mountain structure demonstrate that under sufficient
  strains great bodies of rock both bend and flow.

Its some what explained in this video


Collect & Store Data From API using requests in python to SQLite database

Question: I am new to python and django. But I am trying to set up an app in my project which collects odds data from an API then parses out what I need from the json, and then saves it to a table in an SQLite database.
So far I have the following, which gives me the data I would like to collect and store. The data will need to be called and updated if changed once or twice a day to ensure it's up to date.
def BluebetNrlOdds():
    """Fetch and extract JSON data from Bluebet Australia"""
    import requests
    import json

    # Bluebet Rugby League Odds API.
    link = 'https:/xxxxxxxxxx.com.au/json/reply/MasterCategoryRequest?EventTypeID=102&WithLevelledMarkets' \
           '=true&WithLevelledMarkets=true '
    # Request data from link as 'str'
    nrldata = requests.get(link).text
    # convert 'str' to Json
    nrldata = json.loads(nrldata)

    # NRL ODDS DATA
    for nrl_odds in nrldata['MasterCategories'][0]['Categories'][0]['MasterEvents']:
        competition = nrl_odds['CategoryName']
        event_id = nrl_odds['MasterEventId']
        event_title = nrl_odds['MasterEventName']
        start_time = nrl_odds['MaxAdvertisedStartTime']
        home_team = nrl_odds['Markets'][0]['OutcomeName']
        home_team_win_odds = nrl_odds['Markets'][0]['Price']
        home_team_win_handicap = nrl_odds['Markets'][2]['Points']
        home_team_handicap_odds = nrl_odds['Markets'][2]['Price']
        home_team_1_12 = nrl_odds['Markets'][4]['Price']
        home_team_13 = nrl_odds['Markets'][6]['Price']
        away_team = nrl_odds['Markets'][1]['OutcomeName']
        away_team_win_odds = nrl_odds['Markets'][0]['Price']
        away_team_win_handicap = nrl_odds['Markets'][3]['Points']
        away_team_win_handicap_odds = nrl_odds['Markets'][3]['Price']
        away_team_1_12 = nrl_odds['Markets'][5]['Price']
        away_team_13 = nrl_odds['Markets'][7]['Price']

        print(competition, event_id, event_title, start_time, home_team, home_team_win_odds, home_team_win_handicap, home_team_handicap_odds, home_team_1_12, home_team_13, away_team, away_team_win_odds, away_team_win_handicap, away_team_win_handicap_odds, away_team_1_12, away_team_13)

when you run that code it prints
NRL Telstra Premiership 1047531 Penrith Panthers v Parramatta Eels 2022-09-09T09:55:00.0000000Z Penrith Panthers 1.4 -7.5 1.95 2.85 2.58 Parramatta Eels 1.4 7.5 1.85 3.8 7.6
NRL Telstra Premiership 1047539 Melbourne Storm v Canberra Raiders 2022-09-10T07:40:00.0000000Z Melbourne Storm 1.4 -8.5 2.0 3.05 2.52 Canberra Raiders 1.4 8.5 1.8 3.85 7.9
NRL Telstra Premiership 1047538 Cronulla-Sutherland Sharks v North Queensland Cowboys 2022-09-10T09:50:00.0000000Z Cronulla-Sutherland Sharks 1.7 -2.5 1.9 3.1 3.45 North Queensland Cowboys 1.7 2.5 1.9 3.35 5.2
NRL Telstra Premiership 1047530 Sydney Roosters v South Sydney Rabbitohs 2022-09-11T06:05:00.0000000Z Sydney Roosters 1.6 -4.5 1.95 2.95 3.15 South Sydney Rabbitohs 1.6 4.5 1.85 3.6 5.8

I now need to save that data into SQlite database.
So far i have a seperate database.py file which has the following code in it
import sqlite3

# connect to database
connection = sqlite3.connect('puntsportsau')

# create cursor
c = connection.cursor()

c.execute("""SELECT TABLE bluebet_au_rugby_league_odds
(
    competition        text,
    event_id                integer
        constraint bluebet_au_rugby_league_odds_pk
            primary key,
    event_title             text,
    start_time              integer,
    home_team               text,
    home_team_win_odds      integer,
    home_team_handicap      integer,
    home_team_handicap_odds integer,
    home_team_1_12          integer,
    home_team_13            integer,
    away_team               integer,
    away_team_win_odds      integer,
    away_team_handicap      integer,
    away_team_handicap_odds integer,
    away_team_13            integer
, away_team_1_12 integer)

;""")

connection.commit()
connection.close()

In the models.py file for the package I have the following
# Rugby League Odds

class BluebetNrlOdds(models.Model):
      competition = models.CharField(max_length=255)
      event_id = models.IntegerField
      event_title = models.TextField(max_length=250)
      start_time = models.DateTimeField(auto_now_add=True)
      home_team = models.CharField(max_length=255)
      home_team_win_odds = models.IntegerField
      home_team_handicap = models.IntegerField
      home_team_handicap_odds = models.IntegerField
      home_team_1_12 = models.IntegerField
      home_team_13 = models.IntegerField
      away_team = models.CharField(max_length=255)
      away_team_win_odds = models.IntegerField
      away_team_handicap = models.IntegerField
      away_team_handicap_odds = models.IntegerField
      away_team_1_12 = models.IntegerField
      away_team_13 = models.IntegerField

      class Meta:
          verbose_name = 'Bluebet NRL Odds'
          verbose_name_plural = 'Bluebet NRL Odds'

     def __str__(self):
          return self.name

I am stuck with how I can get the data collected and parsed from the requests to save it to the SQlite database table. I need to do it once or twice a day.
Can anyone give me some direction on what I need to do or show me an example that I can work with to figure it out?
I hope that's enough detail, let me know if you need anything further to assist.
Any help greatly appreciated.
Answer: Welcome to the world of Python and Django;
You can run Django commands with a corn job to build a complete use case.

HOWTO create a custom command call BluebetNrlOdds in the handle function and retrieve the data and save it using the model BluebetNrlOdds. You can also take a look at bulk_create.

HOWTO run a Django command in a cronjob

Quick notes:
In Python, the function name should follow the PEP-8 guide. You can read more about PEP-8 style-guide

Function names should be lowercase, with words separated by underscores as necessary to improve readability.
Variable names follow the same convention as function names.
mixedCase is allowed only in contexts where that's already the prevailing style (e.g. threading.py), to retain backwards compatibility.

Drop the use of database.py. A Django project can handle the cursor connection using Django's settings.DATABASES
I'd advise you to go through building your first Django app, which will guide you on how to quickly start a Django project and the concepts behind using manag.py settings.py and so on


How can I remove excess tile mortar from grout lines?

Question: I laid a tile floor in my bathroom and used too much mortar, which pushed up between the tiles.  There wasn't enough room for grout in some places, and now it looks messy and is difficult to keep clean.  Is there a way to remove some of the excess between the tiles?  I had though maybe I could soak it section by section with vinegar and then use a tool to dig some out.  Another option I can think of would be to do the same without the vinegar.  Does anyone have suggestions?  I'd rather not have to remove the whole thing and start over.  Thanks!
Answer: Depending on your grout gap, an oscillating tool with a grout blade could work well.

If your gaps are substantially wider, a narrow chisel might do the job.
I'd avoid any rotating tool as you're likely to slip and damage your tile.
Comment: For a lighter touch, you can also find manual grout saws; just a handle with a blob of carbide bits: https://www.homedepot.com/s/grout%2520saw. I've also successfully used a carbide scorer used to scribe cement backer board. It's basically a single tooth of carbide. Power tools are definitely the way to go for more than just a few inches...
Comment: +1 for "avoid any rotating tool". First thing that popped into my mind was my little SkilSaw with a masonry blade. Glad you got here first.
Comment: Feel free to post an answer, @spuck. No harm in that. Comments should be reserved for clarification questions, etc.
Comment: Would these tools work for removing the excess mortar as well as grout?  Thanks!


ASCX usercontrol Writing to Text File

Question: Is it possible to from my ASCX usercontrol to write to a text file either on the file system or in a sharepoint list? I tried using a streamwriter but I always get that it cant find the file Ive created.
Comment: definitely possible...can you expand on the problem and/or post your code because I'm not getting the correlation between writing out a file with a streamwriter and "I always get that it cant find the file I've created".  Are you saying that you're able to create the file, but it says it can't find it once you try to write to it?  either way, posting the snippet of code you're using to create/write might be helpful.
Comment: @Rob I guess I just dont know where to put the file, and how to reference the file when I am using the StreamWriter
Comment: for starters, the default behavior of StreamWriter is to create the file if it doesn't exist assuming you're using the constructor that takes the path anyway.  It's probably helpful to know the purpose of the file to give you a better recommendation on where it should go.
Answer: Writing to the file system is very risky if you are in a load balanced environment as there is no guarantee that the code will be executed on the same server that wrote the file in the first place.  However, even if you are on a single server environment, you will still hit deadlock/overwrite/permissions issues if two people happen to be accessing pages that contain your control at the same time.
Factor in the myriad of potential file system security issues and writing to the file system is significantly more work than it is worth.
It would be better to use a SharePoint list for this as it resolves both of the above issues.  The exact code to use to write to the list would vary depending on what you are writing to the list and how (i.e. writing a file to a doclib versus attaching a file to a standard list item)  In either case, I am pretty sure that you can use the MemoryStream object in order to keep everything in memory while you are preparing it to be written.

ASCX usercontrol Writing to Text File


Do aircraft carry commercial VHF radios?

Question: Years ago, I was working in the bush and we used portable radios on something like 154MHz. When it came time for pickup, we were able to talk to the helicopter pilot on that frequency. Since it's outside the air band, I'm wondering if it's normal for aircraft to have VHF radios installed to cover commercial (and maybe amateur) VHF bands.
Comment: Was he a company pilot or one specifically contracted to do the drop/pick? If so, the VHF radio may have been part of the agreement.
Comment: Contract helicopter, who worked for many clients, all presumably with their own frequency allocations. My impression was that the pilot could dial in whatever frequency was required to talk to the ground. It certainly made operations easier and safer, but the helicopter must have had a radio connected into the aircraft in order to use the PTT on the stick.
Comment: 154 MHz could make it one of the MURS frequencies, which are license-free (actually, licensed "by rule") in the US. So anyone can have and use such a radio, for commercial or any other purpose--far less restrictive than Amateur or licensed commercial. However, I see one reference that says "MURS operation is NOT authorized aboard aircraft in flight".
Answer: No, is the short answer. Aircraft generally only carry radios covering the bands they require as standard - i.e., those covering aviation communications and navigation. I have an airband transceiver here and it can't physically be tuned that high. As far as I know, the ones in the planes I fly are identical.
I can't see any advantage in doing otherwise, as standard, as the vast majority of pilots are not licenced to talk on such bands.
In terms of citation, here's a popular general aviation radio, the BendixKing KX 165A
https://www.bendixking.com/en/products/nc/navigation-and-communication/kx-165a

Communication Transceiver: 118.000 MHz to 13.975 MHz in 25 kHz
increments, 118.0000 MHz to 136.9916 MHz in 8.33kHz increments
(118.000 - 136.990 displayed per DO 186a and ED-23B) (8.33 kHz capable
KX 165A only) Navigation Receiver: 118.00 MHz to 117~ .95 M

And, here's another:
https://icomuk.co.uk/IC-A220T/Panel_Mount_Aviation_Radio
(From the manual: https://icomuk.co.uk/files/icom/PDF/productManual/A220-TSO-Instruction-Manual.pdf)

Frequency Range: 118.000 to 136.992 MHz (8.33khz)
Comment: Bendix has quite a few typos in their own specifications: that should be "to 13**6**.975" instead of "to 13.975" and the navigation range should start at 1**0**8 MHz, not 118.
Comment: OTOH helicopters often need to talk with ground personal, which is not trained for aviation communication, nor have such transmitters. Firefighters, but also construction works, transport of goods (e.g. woods). Note: low altitude, low speed
Comment: Good answer.  Some airplanes carry additional radios but, even then, they are usually required for some kind of normal operation.  I had the pleasure of flying a plane with a HF radio and could pick up all kinds of strange stuff.  Pro-communist Cuban propaganda was a notably strong transmission (Radio Havana; english).  And this was while flying over Wyoming.
Comment: @GiacomoCatenazzi I'd argue that's simply mission specific equipment. There's nothing inherent about helicopter operations that means they need such radios. Your average off the shelf GA Helicopter will be airband only
Answer: In Canada, its normal for utility helicopters to be equipped with "agile*" 2m commercial band radios to communicate with the ground, often on a clients Licenced commercial radio channel. almost all oil/gas, forestry work, and firefighting relies on air to ground communications, usually to people without an aviation radio licence
*agile refers to it being capable of changing frequency manually, normal commercial radios need to have pre-programmed channels and cannot change to un-programmed channels.


Expiration of controller action from Sweeper does not work

Question: Having a controller handling rendering of large XML feeds
module Spree
  class FeedsController < Spree::StoreController
    ...

    caches_action :products_out
    cache_sweeper FeedSweeper

    # XML feed in format of `xxxxxxx.com'
    def products_out
      @products = Product.all
      respond_to do |format|
        format.xml
      end
    end
end

Bellow is the corresponding sweeper's sublass:
module Spree
  class FeedSweeper< ActionController::Caching::Sweeper
    observe Product

    def after_update(product)
      # cache_configured? is nil, @controller is nil here, why ?
      expire_action(:controller => :feeds,
                    :action     => :products_out,
                    :format     => :xml)
    end
end

Above Spree::FeedSweeper is called when Spree::Product gets updated, however it seems expire_action silently dies and cache won't get invalidated.
Can somebody explain the issue ? Even better suggest some solution ?
Thanks.
Answer: Which Rails version are you using? expire_action seems to be deprecated after Rails 3.2.14.
Maybe you can try to find out the key then directly clear it with Rails.cache.delete(key).
Comment: I do use Rails 3.2.17. Is it just deprecated but still working ? I cann't see any error in logs.
Comment: I'd really like to avoid such hacks as manual deletion of cache files. As I can see, `caches_action` generates a hash value and prepends to key name.


How can I sanely approach version control and Core Data models?

Question: When we put Core Data model files under version control with git, we always have a horrible time merging changes - the only sure fire way we've found to avoid having to merge in changes by hand is to communicate among the team to block off access to the model while one person makes their necessary changes and pushes, then the next person, etc.
Surely there is a better way to handle this, but as a git novice no obvious solution comes to mind.
Any suggestions?
Answer: While there is no way to get around the merging problem of core data models, I created a git diff driver for core data model files which should make things a bit easier (see README for instructions on how to set it up)
https://github.com/chaitanyagupta/XCDataModelPrinter
Once you've set up XCDataModelPrinter as your git-diff driver, you can do a few things to make merging a bit easier:
Review changes made to the model in our branch
git diff other-branch...my-branch -- /path/to/model

Review changes made to the model in the other branch
git diff my-branch...other-branch -- /path/to/model

After you've reviewed the changes, let's try and do the merge on our branch:
git merge other-branch

If git didn't report a merge conflict, then review the merge results (you will see a combined diff in this case)
git diff --cached /path/to/model

If the merge resulted in a conflict, there's one of two paths you can take: check out the model file in your own branch and manually add changes made to the other one, or vice-versa. Assuming you want to use the first path:
Check out model changes in our own branch:
git checkout --ours -- /path/to/model

Using the diff command above to see the changes made in the other-branch, manually add those changes and review:
git diff -- /path/to/model

Once you are satisfied, just git-add the model file so its no longer marked as unmerged, and commit:
git add /path/to/model
git commit

Answer: As far as I have seen, there is no saner way at this time because the model is stored in a format that does not lend itself to merging.  Normally I do exactly what you do, have one person working on the model at a time to avoid collisions.
Comment: Thanks Marcus. We'll just have to be more disciplined with our communication!
Answer: As soon as you start maintaining migration mapping models, at least you can compare data models and have a look at the changes.
The same compare functionality would also be great within SCM revisions of data models and would make life a lot easier.
Comment: Thanks Martin - we'll take a look at this.


Should I use comparative adj or superlative adj in this sentence?

Question: What is "larger" size of this blouse?
What is "the largest" size of this blouse?
Comment: Pretty much any context can be imagined for the use of any sentence or grammatical point. So we really need to know in what context do you want to say what. In general, if you want to refer to the 'superlative' size,  use *largest.*
Comment: Hello CarSmack!  This sentence is from an examination paper. It asks me to fill out the blanks. What is _____________ size of this blouse?  (large)  So, that's why I am asking for help. The answer is "the largest" on the answer sheet. But if I write "larger", should it be ok???
Comment: If the answer sheet says *the largest* is correct, why would you want to use ***the** larger*? Either one *could* be correct  depending upon the context . Usually a test will tell you what it is testing you on (for example, the comparative or superlative). I can say that either *larger* or *largest* by itself would not be standard English. Also, in English we fill *in* the blanks.
Answer: No, "What is larger size" is not grammatical. You can say "Is there A larger size?" (comparative) or "What is THE NEXT larger size?" (comparative) or, as the answer sheet suggests, "What is the largest size?" (superlative). Of course, in real life, you might more likely say "Is THIS the largest size you have?" (meaning "Don't you have anything larger?") because you usually don't actually want to know what is the largest size, but rather whether they have one large enough to fit you.
Answer: The answer must be "largest". :)
"Larger" means comparing two objects. Since the sentence is not comparing to another blouse, so it must be "largest".
Answer: Actually, it depends. If you want just immediate larger size of the particular blouse, then "larger" is the word. And if you want the biggest size in that blouse, then obviously "largest" should be used.
Comment: Actually, "the next larger" would indicate the "immediate larger size" you mentioned"


Is there an alternative to using a 9V alkaline or lithium battery to power LEDs

Question: I'm looking for an alternative power source to illuminate several LEDs. I'm using a 9V battery to power between 12 and 20 3mm/20mA white LEDs. They are wired in series parallel, everything works fine but a 9V battery will only last approx 2 hours. I'm looking for a rechargeable option that would last 3-4 or 6 hours. Any suggestions?
Comment: You should probably privide more restrictions as there are a lot of options. You have rechargable 9 V batteries or AAA, AA, C, and D batteries (6 in series). In any of these cases, if you dont have enough capacity wire more in parallel. Or just use a wired DC power supply.
Comment: @Matt it's generally better to use larger capacity cells, not parallel cells.
Comment: There are some cell sizes that merit series/parallel arrangements due to price.  Lithium ion is probably your best bet and there are a wide array of options for size and shape of battery.  They offer better charge density and much higher rated current than a 9V, and if you need a voltage higher than 3.7V, you can buy series arranged lithium ion packs, or use a boost mode led driver.  How are the LEDs arranged?  What is the series/parallel arrangement and are there inline resistors?
Comment: The LEDs you're describing are basically the most primitive of the family of "power LEDs", and if you are choosing an array, be aware that power LEDs have an efficiency tradeoff with heat as well as with drive current, so if you have 12 LEDs, and you adjust them to 20mA, and then you have 20 of the same LED on another board and you adjust those to the same total brightness, they will be running at a lower current and use less power at the same brightness.  Looking at it another way, at 3.5V, 20mA, those LEDS are 1.4W at full load.  You can get a single 3/5W LED if you want and run it at 1.4W.
Answer: 9v batteries (commonly known as 'transistor radio' batteries) are inherently inefficient (and expensive) because you are essentially using a "stack" of six 1.5v cells in series to get 9v.  The internal resistance of this stack is eating up a lot of your power.  9v batteries are (should only be) used when something in the device needs high voltage at low current.
Meanwhile, 20 x 20ma = 400ma or .4 amperes.  This is too much big a continuous load on a 9v battery.  I would guess that if you measured the temperature of your battery you'd see a substantial temperature rise, which is causing the battery to burn up much of it's potential energy as heat inside the battery itself.
Ideally you need an op-amp(s) to drive your LEDs.  Remember that you need to drive LEDs with CURRENT, not VOLTAGE. If you can't use op-amps, then use a single 1.5v "D" cell with an appropriate size of current limiting resistor, and wire all of your LEDs in parallel.  You'll still be burning up some of your power as heat in the resistor(s), but this heat will be dissipated outside the battery instead of inside the battery.
Lastly, if you really want to continue using expensive 9v batteries in your present series/parallel circuit, use several of them in parallel to keep the continuous current from each battery below about 50ma per battery (my best guess).  Again, measure the temperature rise of the batteries.  The batteries need to dissipate internal heat faster than they create heat.
Comment: I don't see how op-amps would help here, and a single "D" cell won't provide sufficient voltage to drive a visible LED without additional circuitry.
Comment: There are plenty of simple constant current LED drivers that should be more efficient than an opamp. Also 20mA is a very high current for modern efficient LEDs.
Comment: There are a few things I didn't mention, one being size, it needs to fit in a space that's only 1-1/2" and second has to be completely portable and independent of any other source


I can't sign in to Instagram

Question: I have just started up an Instagram account about a month ago but I haven't been able to sign in. It keeps saying it's the wrong password and email. What can I do as I want to use the Instagram app?
Answer: You are using wrong email id or password or both. If you are sure that you are using correct email id then you can reset the password.
Instagram allows to reset passwords in following 3 ways:

Reset using Email or Username: In this you should have the access of your email id connected to you account.
Reset using SMS: In this, you can get reset link in your SMS and using that you can reset your password.
Reset using Facebook: In this, you can use facebook login to reset your password.

According to Instagram Help Center:

To reset your password, first tap Forgot? next to Password on the log in screen.

To reset through your email address, tap Username or Email, enter your username or the email address you used to create your account and tap search. Choose Send a Password Reset Email.

If you can't access the email you registered with and you didn't link your Instagram account to Facebook, we're not able to give you access to this account.

I can't sign in to Instagram


How to make a sword swing effect

Question: I'm working on a 2d java game on Slick engine and I always wondered how to make swing effects when striking with a sword? How to code something like this what's in the game Hollow Fear? Example from YouTube here.

(Image source)
Answer: You've got two simple options:
Generate particles based on the velocity of the sword in the form of motion lines
Draw up sprites and iterate through these using frames (couple of examples at http://www.spriters-resource.com/genesis_32x_scd/shinobi3/sheet/20808/)

How to make a sword swing effect


Best Viewed in Our App Experience

Question: Due to time constraints, we need to launch a specific experience.  An email goes out, if the user has the app, the link brings the user directly into the app. If the user does not have the app, it goes to a download page (we do not yet have the mweb or desktop experience ready).  We want to put copy in the email that alerts the user to make sure they open it on their mobile device with the app installed.  Has anyone seen functionality out there like this?  Given this isn't the best UX, what is the best practice for wording?
Answer: It's very likely that no matter what, a certain percentage of your users are going to try to open this 1) on an unsupported device, or 2) on a supported device without the app previously installed.
I think both cases are fine, just design for that workflow - the user's next step is to get on mobile and download the app. On desktop, you could show a beautiful landing page outlining the benefits of getting the app; maybe the user could click a button to have the app store link sent to their mobile device by SMS.
On mobile, you can provide buttons to the respective app stores, and a smart app banner that links directly to the app in the store on the user's device.

(Code implementation is off-topic on UXSE but I promise that smart app link banner code is extremely easy to implement, and information is easy to find.)
Once the user has the app downloaded, perhaps you can highlight your new feature on the welcome screen.
Comment: Thank you!  What would you do when they open on a desktop?  The page they will land on is basically an "oops please open on your mobile device" page.  Any best practices on the copy for these types of pages?
Comment: I'd use that page to make the user really want to download the app - sell it to them. And let them enter their mobile number so you can send the app store link to it via SMS.
Comment: If they already have the app, hopefully they're going to want to use it once they are reminded how awesome it is!
Comment: Thank you! Awesome thoughts
Comment: I just came across a QR code on a landing page designed to take the user directly to the app - I think that might be a great idea for what you're working on.

Best Viewed in Our App Experience


Alternative of bash's `history -p` in zsh?

Question: In bash, history -p does history expansion on its argument; What is the alternative in zsh?
Answer: I'm not aware of any, but see the histverify option which changes the behaviour of history expansion so that when you press enter on a line that contains history operators, the expansion is performed in the editor buffer without running the command.

$ setopt histverify
$ echo !!Enter
$ echo setopt histverifyEnter
setopt histverify

Also note that in zsh like in csh (where history expansion comes from in the late 70s) history modifiers (like :h, :r, :A...) can also be applied to parameter expansions ($var:h...).
And the whole history is accessible with the $history special associative array.
Keys of that associative arrays are the history numbers, and contrary to regular  associative arrays where the order is undefined, $history[@] is sorted in descending order on the numerical value of the key.
So ${history:0:1} is the last history entry. So, you can use parameter expansion operators to get the same result as with history expansion operators. For instance: !$:h, could be ${${(z)history:0:1}[-1]:h}
Answer: In bash you can expand a command by doing this:
history -p !23

So if in 23 you have ls -l the, return will be:
ls
-l

In zsh i am able to reproduce a similar (but not identical) behavior by doing this:
history 23 23 | xargs -n1 | tail -n+2

Comment: ITYM `history -p '!23'`. In `zsh`, just use `print -r -- $history[23]`
Comment: I tried but nothing happens =(. Try history -p !23 instead of history -p '!23'... for what is really that ? =(
Comment: Thanks, but I need more sophisticated behavior; I wanted to run `history -p '^(#b)E(?)^E${(l:2::0:)$((match[1]+1))}'`. I wrote that function using `fc` in the end.
Comment: I cant imagine the results you want to got. I just received "History Expansion Failed" (in bash). Can you post in you question what you have, and what exactly you want to get or do? Thank you. Maybe i have a easy solution!


How to make blend file take up less space

Question: Some of my models on my computer are taking up around 400-500 MB and I want to shed some space on my computer. I tried deleting objects and checking for animation data but the best I could get taken off was about 20 MB. How can I get a model to take up s few space as possible?
Comment: Related: https://blender.stackexchange.com/q/51128/
Answer: A few things come to mind. These affect not only filesize, but also performance.

Keep modifiers procedural as long as you can (Subdivision Surface, Array, Mirror, etc. Basically any modifier that adds geometry.)
Use linked duplicates, instancing and collection instances whenever you can. Instances don't increase filesize and are also better performance wise.

Procedural Modifiers - filesize 650KB

Applied Modifiers - filesize 20MB (30x increase)
Answer: Use the Compress option
When you save your blend file, click on the "gear" icon (or press N), then check Compress.

The file will take less disk space (50% less in many cases, and sometimes even less) ; but it will be a bit slower to save and open it.


Is there a term for words or expressions that have meaning in both directions?

Question: I'm talking about words like 'comfortable' (the chair is comfortable, or, I am comfortable in the chair) and 'curious' (it is a curious painting, or, I am curious about that painting). So, is there an official term for such words or expressions? (An example of such an EXPRESSION would be 'make a short list' (to be considered a prime candidate by a prospective employer, or, to make a list of employment opportunities to explore in detail later).
Answer: Some people consider such words auto-antonyms or contronyms. The words you mention are, in fact, a particular kind of auto-antonyms as they can be used to reflect an opposition in terms of subject-object/object-subject relationship. For example, while "buy" and "sell" are antonyms, "rent" is ambiguous as it can be used in both directions ("bidirectional" or "two-sided" would be a good description for this kind of words). As a matter of fact:

I'm renting this apartment

may mean that "I" is the landlord or the tenant.
Another example is the verb "smell":

I smell the rose. (I experience the smell of the rose)
The rose smells nice. (The rose produces the smell I perceive)


Meteroids escaping the system

Question: So the sun or any star has a certain gravitational pull. Technically the gravity extends infinitely only it will just become really small. If there is a meteroid around a star how do I calculate when the meteroid is far enough away so that you can say it escaped the system? Or that is ejected from the system? So I know the mass of the star and the meteroid can I calculate with only that information at which radius the meteroid will escape the system. If not, could I calculate it if I also knew the semi major axis and eccentricity of the asteroid?
Comment: It's just the escape speed.
Comment: If you know the mass of the star and the position and velocity of the asteroid with respect to the star, it's a trivial two-body problem to show whether the asteroid's orbit is closed.  The tricky part is that asteroid "escapes" (where the asteroid was originally in a closed orbit and then is not) are the result of interactions with third bodies.
Comment: @antlersoft okay but if you do not know the velocity of the particle can you still calculate if the orbit is closed?
Answer: Given the mass of the star, $M$ (or its gravitational parameter), the object's velocity and its position (vector), you can determine if the object's orbit is closed, as @antlersoft wrote in a comment.
Assuming a simple two body problem (with the asteroid having mass 0), you can determine whether the object is in a closed orbit by checking if the velocity is greater than the escape velocity at the given distance from the star as $v_{esc}=\sqrt{\dfrac{2GM}{r}}$, where $G$ is the gravitational constant, $M$ is the star's mass, and $r$ is the distance from the star. If the velocity of the asteroid is less than this value, its orbit is closed. If not, then the asteroid will escape the influence of the star.
If you don't know the velocity of the asteroid, you cannot determine if the asteroid is on an escape trajectory. However, if you do know the semi-major axis of the orbit or the eccentricity, you can tell if the orbit is not closed - if the semi-major axis is positive, the orbit is closed. If the semi-major axis is negative, the orbit is hyperbolic (not closed), and if it's $\pm \infty$, the orbit is parabolic (also not closed). If the eccentricity is less than 1, the orbit is closed, and if it is greater than or equal to 1, it is not closed. Hopefully this clarifies things.

Meteroids escaping the system


Text in image is low or high frequency component?

Question: Text present in captured images is high frequency or low frequency component?Why?
Answer: The edges of the words will probably contribute to a high frequency, the background of the text and the portion within the boundaries of the letters of the text will be otherwise.
Answer: When text is more, it is a high frequency image. If the image has only one or few letters in larger font size it is a low frequency image. This is because of following reasons:
What do frequencies mean in an image?
If an image has large values at high frequency components then the data is changing rapidly on a short distance scale. e.g. a page of text
If the image has large low frequency components then the large scale features of the picture are more important. e.g. a single fairly simple object which occupies most of the image.
In other words, High Spatial Frequencies represent abrupt spatial changes in the image, such as edges, and generally correspond to featural information and fine detail. Low spatial frequencies, on the other hand, represent global information about the shape, such as general orientation and proportions.
Answer: The letter boundaries are high frequencies and the letter interiors are low frequencies. So, thicker fonts mean more low frequencies and thinner fonts means more high frequencies.
However, this applies only if the text color is constant and the text contrast is high (e.g., black test on white background). If the color varies for a letter, then the variation will determine the frequency response of the letter interior. And if the text has low contrast, the high frequency components of the boundary will not be as prominent as for black text on white background.
Answer: Actually this is very general. It can also depends on the clarity of the text.
Comment: Can you expand more on what you mean by "clarity" in terms of signal processing?  The system is flagging this as a low-quality answer... and it's a little short!


C# xna/monogame ghost trail effect

Question: I would like some know how can someone make an animation like this, in Monogame specifically.Since i am completely clueless on how to go around this i how should i go about this ? I hate asking questions this general, but since i don't know how to do that, adding any more to the question wouldn't really help. Even the general concept behind this is highly appreciated.
Answer: This animation is likely a bunch of different colored sprites moving or fading in to follow the path of the trail. Look up particle systems. They let you control many sprites/objects at once easily with a set of rules to define their movement.
For this example, you can start with a white circle moving in pre-defined path. Using trigonometric functions is a good way to easily make some curved paths, and you can use bezier curves or splines, although they are more complex to define mathematically. You can also just make it follow the mouse cursor.
Either way you choose, once you have the moving circle, you make a list of sprites to store them in different sizes and colors depending on their order in the structure. You pass on the location to the other sprites in the list the on each frame to create a motion lag, which makes the trail.
This tutorial does a great job at showing how to make particles with this kind of behavior in XNA (MonoGame follows almost the same syntax).
Comment: wouldn't that mean that i would have to use the draw() method a lot ? I've heard that this is inefficient
Comment: however this tutorial is exactly what i was looking for, i will study it in detail soon and use it in my game i'm making. thank you very very much :)
Comment: By default the Spritebatch defers rendering so all sprites are rendered in as few calls as possible. It can support up to 2048 sprites (XNA 4 implementation) before it is forced to start a new batch. If you use the same texture with the same sprites, you won't need to optimize a lot.
Answer: What you are looking for is called ribbon trail. While a particle trail does the job as well there are a few problems with using particles:

missing particles at high speed
gpu overdraw
effect limited to particle settings

However if this effect fits your game better then here is a good tutorial: World of Goo Cursor
This porblems were the reason i implemented a 2d ribbon trail in my self made xna like ios/opengl es 2 framework. here is a gist of the objective-c code (syntax is different, functions are more or less the same): Ribbon Trail
My implementation is not perfect and i can list you my known issues:

The end of the trail is ontop of the beginning (fix: reserve vertices)
There is a buged triangle at the start of the trail (had no time to work on it since ages)

but this should give you a good idea how to get this effect (trail + round particle on top to make it smooth or generated verticed attached to the trail to make it round)

C# xna/monogame ghost trail effect


how to get a boundingbox for multiple items in wpf?

Question: I have several items, i want to calculate a minimum rectangle in which they can be fit, but items are rotated to some degree, or skewed or both. So how do i get the least rectangle which can contain all ?
Answer: You can get the bounding Box for each item, calculate its four extreme points, then apply the transforms on them (skew, rotate, ...)
Then you can easily calculate the bounding box by computing the min and max x and y for all of these points.
Answer: Here is an link to an implementation of a Dynamic Canvas.  This control automatically sizes itself to fit its contents, so the answer to your problem can be found in this code.  Look at the MeasureOverride function.
Answer: Do a foreach on the list of items you want.  In each iteration of the loop, get the item's Canvas position (upper left) and add ActualWidth/ActualHeight to get lower right point.  Take the upper left and lower right points and call Transform.Transform to get the ACTUAL upper left and lower right points.
Keep track of min and max upper left and lower right to get your bounding box.


Fill in blanks in multiple columns in Excel

Question: I have about 50 columns in my spreadsheet and around 5000 rows. In these 50 columns, there is either "TRUE" or it is blank. What's a shortcut to changing all of the blank cells to "FALSE"?
Answer: First, select the area you'd like to modify.  In the Home tab of the ribbon is the "Find & Select" menu; click "Go To Special", select "Blanks" and click OK.
If you'd like, the keyboard shortcut is [Alt] + [H] + [F] + [D] + [S] + [K]
Type in the value you'd like to be in the selected cells, hold down [CTRL] and press [Enter].  The value will fill in the empty cells.
Answer: Search-and-replace, searching by cell for empty quotes "", replacing with FALSE.
Some versions of Excel may require a different expression to target the empty cells; I've always found it through experimentation and the local built-in help facility.
You can also Export to CSV, open that file in a text editor, do the search-and-replace there, and then load the CSV into a new spreadhseet....


What does a fitted value mean in dshw forecasting package?

Question: I have a double seasonal data. I wrote the following code to find the best fit model and find fitted values:

orders <- read.csv("DataForR.csv", header = TRUE),
  NumOrders <- orders$Orders,
> period <- orders$Period,
  OrderTimeSeries <- msts(NumOrders,seasonal.periods=c(24,7*24)),
  fit2 <- dshw(OrderTimeSeries,24,168,336,alpha=NULL,beta=NULL,gamma=NULL,omega=NULL,phi=NULL,lambda=NULL,armethod=TRUE,model=NULL),

my original time series plot is as follows:

but the fitted values are as follows:

I wonder what does a fitted value mean? does it mean using the fitted model, the forecast values for the training dataset are fitted data? how can I have both series in one plot so I can better compare their trends? Thanks
Answer: The fitted values correspond to an optimal 1-step ahead forecast.
See: http://cran.ms.unimelb.edu.au/web/packages/forecast/forecast.pdf


How can webpage made in flask, be accessed in web?

Question: We have made a code for webpage made of flask, and access it locally by inputting the IP address of the raspberry pi e.g(192.168.0.1:5000) in the browser. In reference with (https://diyhacking.com/raspberry-pi-web-server/#comment-4651), can we proceed to setting up the static ip(STEP 4: Give your Raspberry Pi a static IP address, in the URL) and setup a dynamic ip without installing Apache?
Answer: If you can always reach your Pi on your local network by visiting 192.168.0.1:5000 then the Pi already has a static local IP address. If that IP address changes occasionally then the IP address is being assigned by Dynamic Host Configuration Protocol (DHCP), controlled by your router. You want to make sure the Pi's local IP address is static before continuing.
With regard to installing Apache, Flask's documentation currently states:

While lightweight and easy to use, Flask's built-in server is not
  suitable for production as it doesn't scale well and by default serves
  only one request at a time.

If you can live with only serving one request at a time and don't care too much about security you can press ahead and open your Pi up to the big bad world. I would recommend, in the strongest possible terms, that you don't do this and use a recognised server package such as Apache. It'll work better in the long run and should give you much more control over what's happening with your site(s). The deployment documentation has a list of viable options and accompanying instructions.
Answer: If you don't like the idea of installing apache, you could also consider using something like Heroku or PythonAnywhere to host your site. Both have some free options for small web applications and there are tutorials available to get you started.


Short story made of memos about re-purposing nuclear warheads?

Question: I am trying to hunt down a short story written as a series of memos between government agencies about how to use leftover nuclear warheads. The suggestions are completely ridiculous (urban renewal, etc) and the story culminates in someone sending in his resignation.  My dad thinks he read it in Analog in the 1970s... but he's not sure. Help me identify the story?
Comment: [Perhaps ridiculous, but not all that far from reality.](https://en.wikipedia.org/wiki/Operation_Plowshare)
Comment: A bureaucracy can come up with, and actually implement _anything_ (maybe there is a pithy description for that? "The tyranny of small decisions by people with no skin in the game" or something analogous). That's why [BuSab](https://en.wikipedia.org/wiki/Bureau_of_Sabotage) was invented ... in another universe. Motto: _"In Lieu of Red Tape."_
Answer: "Request for Proposal" by Anthony R. Lewis was first published in the November 1972 Analog. It is written in the form of interoffice memos about using nuclear warheads for slum clearance and urban renewal:

The obvious solution to all these problems is the selective use of low-yield tactical nuclear devices as the major components of a modern, effective slum-clearance and riot-control program. It is expected that sufficient devices can be transferred from the Department of Defense, at cost, in the initial stages of the program. Further downstream, alternate sources for the devices can be sought on a competitive bid basis, thereby decreasing costs.

One official (Chief, Readjustment Division) resigns:

Since I see no possible way to prevent this program from being actualized in my present position, I wish to tender my resignation from the Department.

That resignation is not the culmination of the story, which ends with the "request for proposals" (ellipsis in original):

Gentlemen:
The U. S. Department of Housing and Urban Development, Robert F. Kennedy Research Center, solicits your organization for a proposal for a study aimed at defining the requirements for, and the economics of, the use of low-yield nuclear devices in the optimization of inner-city interaction stabilization.
This solicitation is covered by the following documents . . .

This story has been reprinted in several anthologies, among them Space Mail, an anthology of sci-fi stories told in the form of letters or memos, which was combined with another anthology (The Future in Question) to form Isaac Asimov's Science Fiction Treasury.


How to display unlisted group names through vf page in desktop and listed and private groups in sf1 i.e. mobile

Question: I want to display the unlisted group names when the vf page is previewed in desktop and listed and private group names when opened in mobile(salesforce1). How can be this possible?
Answer: It is very easy. We need to call an action function from a java script function by differentiating sf1 and desktop browser in  java script function  and in action function we can query the list with if else condition. I mean, if it is browser it should display unlisted group names or else it should display listed and private group names.


Whatsapp: "The download was unable to complete. Please try again later" for received voice messages and stickers

Question: Received voice notes or stickers don't download since a few days ago. The message shows a down-arrow icon, I click it and the circle around the icon spins for a few seconds and then shows this error:

Any ideas on what else to try for this error or how to debug it? This is what I have tried, to no avail:

Internet connection is fine, other phones with Whatsapp using that connection work and every other app in this phone works fine. Tried WiFi and mobile data connection
Phone date and time is correct
Enough disk space
Cleared Whatsapp cache and also wiped Android cache partition in recovery
Whatsapp updated to last version
Backup messages, uninstall Whatsapp, install Whatsapp, restore messages
Tried with auto or manual download in Whatsapp options
Answer: As a workaround, it works using Whatsapp Web


Why can't I accept both answers?

Question: In my question What does "do" mean in "What do I do"?, there are 2 answers that are helpful. But when I accept the other one the check mark goes away. Can I only accept one? I want to accept both.
Comment: Relevant: http://meta.stackexchange.com/questions/2786/accept-multiple-answers-or-split-bounty-among-several-users. What I would do is just commenting under a non-accepted one that it also has valuable information so that others did not hesitate to upvote it. P.S. Downvote here on Meta indicates my disagreement and does not change your reputation.
Answer: You can only accept one answer, which is the one that helped you more than the other ones. This is by design.
If there are more than one answer that helped you, you can up-vote the ones that helped you, and accept the one that helped you more than the others; you could also assign a bounty to the other answers.
Even if it were possible to accept two answers, there would still be the problem when the answers that helped you are three; if it were possible to accept three answers, there would still be the problem when the answers that helped you are four.
IMO, accepting more than one answer would give to accepting an answer less importance than it actually has. In the case it would be possible to accept all the answers, accepting answers would completely lose its meaning. (What would accepting answers mean when all the given answers are marked as accepted?)
Comment: "If everyone gets to be special, then nobody is."
Comment: I disagree, several answers can be equally good. With a little ingenuity the problem can be solved. Or we can accept it's a flawed feature and go on, but recognize it is flawed first.
Comment: @Theta: I don't regard it as flawed. Sure, you can only pick one answer as the "best", but you can upvote as many as you want. More than once, an O.P. has left me a comment saying that my answer was very helpful, even though a different answer was selected as "best." Those instances never struck me as an injustice, a bad design, or a flaw in the system.
Comment: An example of my question where both answers are equally good:http://ell.stackexchange.com/questions/4023/what-are-the-little-legs-on-the-bottom-of-a-laptop-called
Answer: It seems to me that an accepted answer ought to be one that totally solves the problem, and is no worse than other answers.  This is much more objective than "best" or "most helpful". I have no problem with there being thirty accepted answers on some question, but only one on most questions. I would implement this feature request.

Why can't I accept both answers?


What does "human corroborators" mean in this context?

Question:
In the 1950s the United States government made contact with a race of
  technologically advanced beings known as the Ghin. The Ghin leader, a
  brilliant scientist named Cronos, had come to earth seeking a cure for
  a deadly plague threatening to annihilate his race. Cronos believed
  the cure to the plague could be found within human DNA, which was
  remarkably similar to that of the Ghin.
Embroiled in a deadly cold war with the USSR, the United States
  government agreed to provide Cronos asylum and, more importantly,
  access to US citizens as test subjects in exchange for Ghin
  technology. With the bargain struck, a group of high-powered
  individuals known as the Majestic 12 initiated a secret government
  program. The project, codenamed Aquarius, saw the creation of several
  underground facilities classi ed far beyond top secret. For over  fty
  years, Cronos conducted his gruesome experiments on an unsuspecting
  population with the aid of those who were entrusted to protect them.
With the fall of the Soviet Union and the end of the cold war,
  relations between the Ghin and the US began to deteriorate. Only
  Cronos' threat of exposing the Faustian deal kept the US government
  continually supplying test subjects.
Less than twenty-four hours ago, several test subjects managed to
  escape the Subterra Bravo facility. Their actions led to a complete
  breakdown in relations between the human corroborators and Cronos'
  minions. Having planned for this eventuality, the US government has
  enacted Omega Protocol . . .

Source: Level 7 [Omega Protocol] boardgame manual
I looked up the word corroborate but I can't grasp the relation between its meaning "to confirm/support a theory/finding" and these "human corroborators" from the text. What are they supposed to confirm?
Answer: You're right, "corroborate" doesn't make sense here. I think the author meant to use the word "collaborators", instead.
From Wiktionary:

collaborator (plural collaborators)
A person who works with others towards a common goal.
     A person who cooperates traitorously with an enemy.

In this context I think it would be the second meaning, as the US is cooperating with aliens which are harming its citizens.