Forgiveness from kufr

Question: Can I Ask forgiveness from Allah if I commit kufr unknowingly or I should be sure that I committed kufr for example O Allah forgive me I if I commit kufr unknowingly
Comment: What I have commonly seen on this site is the mis-concept of `kufr`. Check this out: islamiqate.com/3998/what-is-the-concept-of-kufr-in-quran. And, this will help you with understanding forgiveness if you want reference: https://islam.stackexchange.com/questions/28884/i-need-help-in-seeking-forgiveness-from-allah?rq=1
Answer: Salaam,
The fact that you did it unknowingly and want to ask for forgiveness, shows your strength in faith. There are so many ways you can ask for fogivness. You can make dikhr and recite astaghfirallah, you can make sure to repeat it in your daily prayers, and you can simply hold out your hands and make dua. Remember, that Allah (swt) is the oft-forgiving most-merciful. :)
Hope that helps:)
MuslimGap
Answer: Of course when you run to Allah and ask for his forgiveness and make tawbah and promise never to do it again Allah will forgive you and when you are worried this is a sign that you are a true believer. And remember this Allah loves it when you ask for forgiveness, or ask him something he loves it when you do this so remember that and never despair from Allahs mercy never ever think that way EVER.
And Allah knows best.

Forgiveness from kufr


Copy text from mac to ipad

Question: I'm often reading stuff on my Mac but then I want to switch to my iPad to read it there. Is there a simple way to copy text or an URL from my Mac to my iPad?
Answer: Safari's reading list and iCloud works well to synchronize a list of URL between Macs and iOS devices. The Simplenote app and web app work well to let all your devices keep track of text documents. You only need to pay for the latter if you want enhanced features or avoid the advertisements that are minimal and generally very tasteful.
Answer: Pastebot, while not iPad native, is excellent for pushing images/text and various other bits between a Mac and iOS device.
If you're looking for a longer lasting solution, check out Instapaper.
Answer: To copy an URL you could try Jumping URL as well as myPhoneDesktop which can also push text to the Notes app on the iPad.  Let me know what you think about these.  In the meantime I'll look for some more apps.
Comment: I can't find the jumping URL but the myphonedesktop is what I'm looking for. Not sure it's gonna be worth the $5 ;-)
Comment: Oh, I think it's worth the 5 dollars.  You can push links, text, images, and calls from you desktop to your phone.  Also the desktop version is available on all platforms.  And, say you are using a friends computer, you can log in on their website and use the online version.
Answer: A free no additional app solution exists If you are using iCloud, you can use the built in Notes Application on the iPhone / iPad and coming soon to Mac OS X via Mountain Lion.
But til then on Lion Notes can be oddly be accessed via the OS X Lion Mail Application Notes function.  You can copy paste to Notes and then grab results from whichever platform you wish.
Answer: Also try NoteFile for iOS devices and the corresponding widget for Mac. It syncs beautifully between both almost instantly. It's made by junecloud.com
Comment: Welcome to Ask Different, user20578! Thanks for posting an answer! Can you please provide a link to NoteFile? Thank you!

Copy text from mac to ipad


Are there Christmas markets in Switzerland?

Question: I've been in Germany on christmas and almost every city has a Chrismas Market. Are there Christmas markets in Switzerland? Which are the most famous/interestings? When do they end?
Answer: This page list all the big Christmas markets in Switzerland. I can really recommend those two that are in the main stations of Lucerne and Zurich. It sounds weird but they are really nice. As a plus next to the Christmas market in Zurich's main station, there are a lot of open air bars in the courtyard of the Landesmuseum where you can get Glühwein and Raclette, typical food and drink during Christmas in Switzerland. As lejohn already mentioned, also the Christmas market in the Niederdörfli is worth a visit.
Here you see a picture of the Christmas market in Zurich's main station. The huge Christmas tree is decorated with Swarovski crystals.

And here is a picture of the Landesmuseum's courtyard where you can get Raclette and Glühwein. It is also possible to do some ice skating there:
Answer: There are a couple of Christmas markets in Switzerland, just pick one next to the place you are staying.
A nice market is the one in the old town of Zürich. It is located along Hirschenplatz, Niederdorfstrasse and Rosenhof. In 2011, it takes place from the 8th to the 23rd of December. Its opening hours are from Monday to Friday 11am - 8pm and on Saturday and Sunday from 11am to 6pm.
Comment: Note that that list has a 'more results' link at the bottom, otherwise you miss out on some (notably Montreux, which is the only one I've ever visited: I must admit that even though people come from far and wide, I'm not *sure* it's worth travelling more than an hour for).
Answer: As I remember, in Geneva at least, there are open air markets on a weekly basis. (At least in the late 1990s, when I was there.) They do not "end," therefore, and there would be something for Christmas.
Comment: But a German Christmas market is not simply a market open around Christmas time!
Comment: @Annoyed: Geneva is in the FRENCH, not German-speaking part of Switzerland.
Comment: Sure, but once again the question is about German Christmas markets, not about regular markets open for Christmas.
Answer: Another place in Swiss French part is Montreux, it is probably the biggest and longest running Christmas market in the French-speaking region.
Near Geneva, there is one in Carouge (the town is next to Geneva).
Apparently the biggest Christmas market in Switzerland is the one of Basel
This site is resuming all markets in Switzerland (and other countries).


What is the original "origin story" of the Fantastic Four?

Question: I've seen both of the recent Fantastic Four movies, but I seem to remember a different "origin story" in the comics for the Fantastic Four.
Comment: As I recall, the original comic had them going up in a rocket, and being exposed to cosmic rays.
Comment: @K-H-W - You are correct, Sir.
Answer: The original comic serial (Fantastic Four #001 - 1961) had our four heroes going up in a rocketship which was bombarded by cosmic rays.
Comment: Gotta love comic science. If the Rays are pure light but can pass through shielding and people can't feel them, why could they cause the hailstone like tapping on the rocket?
Comment: In the second issue it is added that they intended to go to Mars.
Answer: The original origin story for the Fantastic Four, in the early 1960s comic book, has the four heading into space in an experimental rocket ship which is then bombarded with cosmic rays, giving the team their powers.
Comment: Wasn't there something about flying thru a cloud of radioactive gas from a volcano?
Comment: Not that I can find. The first two movies (including an unreleased one) also involve them going into space and being hit by cosmic rays. The latest (2015) movie changes the scenario to them being caught up in a teleport experiment to another dimension (or something like that, haven't seen it based on the terrible reviews!)
Answer: As far as I can tell, there's never been any deviation from the whole "cosmic rays in space" origin.
The 1967 cartoon had this as its origin

According to the Marvel Wiki that is also the story pitched in Fantastic Four #1 (1961)

To beat the Communists into space, scientist Reed Richards, sister and brother Sue and Johnny Storm, and pilot Ben Grimm sneak off into space in a rocket. In space, the four are bombarded by cosmic rays. The auto-pilot lands the ship back on Earth, where they find themselves physically transformed and possessing remarkable new abilities.
Comment: The OP is probably thinking about the latest FF movie, where the origin story was changed to something about teleporting to a parallel dimension.
Comment: Yes, the teleporting version resembles their origin in the *Ultimate* universe.
Answer: The main core of the FF's origin has not changed comics, only certain aspects are amended to keep the story somewhat contemporary.
In the original book, reed and his team are testing a "missile" to beat "the Reds" into space.  In more recent telling (mostly updated by John Byrne) the team are testing an experimental star drive of Reed's design.  The core remains the same - the test is being done surreptitiously, and outside of accepted scientific practice, i.e. testing on humans, and an unexpected cloud of Cosmic rays caused their mutations.
These little updates are made because the original stories were written decades ago, and since it's accepted that every comic story about one of these characters has occurred in the past X years (a theory Byrne called The Sliding Seven - now considered closer to ten or fifteen) some anachronistic parts of the origins need updating.  Tony Stark originally built his weapons to be used in Vietnam; Byrne updated that to more modern conflicts, and the films made it Afghanistan and other nondescript areas of the Middle East.  The core of the origin is untouched - he's captured by The Bad People and is forced to build a weapon.


Gray Out Past Days in Sharepoint 2013 Calendar

Question: Anyone have .css or code to gray out past days in a Sharepoint 2013 calendar?
Answer: Are you just looking for the background to be a different color? Here's what I pieced together in Javascript to do that, maybe you can use something similar for what you need. I added a content editor webpart to the calendar view page, referenced JQuery (we keep it in a local document library on the root site), and add this:
<code> $(document).ready(function() {
        var today = new Date() ;
        today.setHours(0);
        today.setDate(today.getDate() - 1);

    var dayrows = $('tr.ms-acal-summary-dayrow td');
    var itemrows = $('tr.ms-acal-summary-itemrow td');
    $(dayrows).each(function(i) {
        var thisDate = new Date($(this).attr('date'));
        if(thisDate < today) {
            $(this).addClass('showGray');
            $(itemrows[i]).addClass('showGray');
        }
    });
  });
 </script>

<style>
td.showGray {
    background-color: gray;
}
</style>
</code>
The standard column has rows for the date displayed, then the larger piece where the events go. The first one has an attribute of 'date', so you can use that to test if it's less than 'today'. I'm actually surprised it worked without messing around with asynchronized calls, but this worked for me on my test calendar.
Comment: This is very close to what I need - the only problem is that it adds a gray background to today's date as well as past days.  I've tried 'today-1', but haven't been able to tweak the code to re-define the showGray class successfully.
Comment: I noticed that - I've updated my answer to do the today-1 - that way it stops on yesterday. Right after the var today, set the hours to 0, then subtract one from the date.


07 3.8l Chrysler Town and Country Stalls when accelerating

Question: I'm looking at purchasing a Mini van  that has pretty good mileage on it. Only 80k but has the issue I described in the title.  The codes read "Mass airflow sensor, Throttle body Position sensor". the current owner has replaced  the throttle body position sensor, Crankshaft position Sensor, Fuse box, and computer but is still having the issue. I'm thinkin that if this can be fixed its likely going to be a very long lasting vehicle. Does anyone have any thoughts on what the issue might be?
Comment: Welcome to Motor Vehicle Maintenance & Repair! Not sure on the T&C, but quite a few vehicles have a "relearn" procedure which needs to be done when replacing the TPS. What you're describing certainly sounds like a TPS sensor issue.
Comment: A faulty MAF sensor can cause this also.
Answer: There's a host of problems that can be wrong with this, especially now that the computer has been changed. It is probably going to be a fault or faults in one or more circuits. I have very good experience with this generation of T&C. If there's little to no rust problems I would take it somewhere that's good at electrical diagnostics and pay for a prepurchase inspection. This should make your decision much easier.


What is a zipper, and how does it relate to a tree-like structure?

Question: I was reading a chapter in LYAH which didn't really make sense to me. I understand that zippers can arbitrarily traverse a tree-like structure, but I need some clarification on it. Also, can zippers be generalized to any data structure?
Comment: A zipper is something that you should always keep closed, especially when traversing a tree.
Comment: This is probably more appropriate for [CS.SE], though the work generalising zippers involves quite some technical machinery.
Answer: A zipper, in general, is a data structure with a hole in it. Zippers are used for traversing/manipulating data structures, and the hole corresponds to the current focus of the traversal. Typically there is also an element of the data structure under consideration, so that one has a (list) zipper and a list or a (tree) zipper and a tree. The zipper allows the programmer to efficiently move around the data structure, even replacing the element at the focus. The pair of the zipper and the element in the focus satisfy the constraint that placing the element at the focus in the hole gives the original data structure.
Zippers can be generalised to arbitrary inductive data types. The concept can be defined in type-indexed fashion (See type-indexed data types). They are also related to the idea of the derivative of a data structure, and has been studied from a Category Theoretic perspective.
Answer: A zipper is in general a pair of things: it's a structure-with-a-hole, a focus, representing where in the structure you are, together with a path, recording how you got to that focus. (This path is LYAH's trail of breadcrumbs.)
The path is how you actually apply changes to the structure: "go down, go left, increment the value". By repeatedly applying "go up" (go_up in Huet's paper) at this point, you can retrace your steps and end up with a new, mutated, copy of the original structure.
They can indeed be generalised to other structures:

Scrap Your Zippers uses generic programming in Haskell
Clojure's zipper gives you a "pluggable" zipper: when you create a zipper on a structure, you pass in functions specific to your structure


Hand-drawn 3 Illustrator help

Question: I have made the following using Adobe Illustrator, the 3 was made bespoke from my hand writing (which is quite poor!) I want the curve of the 3 to be more symmetrical & perfect... How can I do this?
Answer: You could overlay a circle on the bottom portion of the three. Make sure the stroke is the width you're looking for. Expand the object.
Then use the shapebuilder tool to add and subtract pieces of the circle and the three until you get the symmetrical look that you're going for. If there are any rough edges, use the smooth or pen tools to even them out.

Hand-drawn 3 Illustrator help


Is it possible to recover precious materials from a weapon to use for crafting other weapons?

Question: My players have found low-grade silver swords and I was wondering if they could get the silver from the swords to craft other weapons with it?
Comment: Point of clarification: are the swords treated with alchemical silver (and therefore especially good against lycanthropes) or swords made of pure silver (and therefore probably not well-suited for use as actual weapons)?
Comment: You're asking specifically if there's a rule in pathfinder that covers this?
Comment: @BenBarden I think that might be in the realm of answers to cover, right? Whether there is a specific rule for it, if you can't get the silver exactly then if there might be another way to use the material for crafting (like how D&D 4e had arcane dust or whatever it was called), if not whether approximate support exists, etc.
Comment: They have the trait silver (Silver weapons deal additional damage to creatures with weakness to silver, like werewolves, and ignore the resistances of some other creatures, like devils.) They are [Low-Grade Silver](https://2e.aonprd.com/Equipment.aspx?ID=277) Longsword like on page 579 of the Core Rulebook.
Comment: @BenBarden Are you talking about the 1e versions of the silver options? Silver weapons [only have lower durability](https://2e.aonprd.com/Equipment.aspx?ID=277) in 2e, and [silversheen](https://2e.aonprd.com/Equipment.aspx?ID=134) is short lived
Answer: The Crafting rules are vague
The section on Crafting with Precious Materials section, as you may have read, only says

When you Craft an item that incorporates a precious material, your initial raw materials for the item must include that material; at least 10% of the investment must be of the material for low-grade, at least 25% for standard-grade, and all of it for high-grade. For instance, a low-grade silver object of 1 Bulk costs 20 gp. Of the 10 gp of raw materials you provide when you start to Craft the item, at least 1 gp must be silver. The raw materials you spend to complete the item don't have to consist of the precious material, though the GM might rule otherwise in certain cases.

It doesn't specify what state the material needs to be in so it is reasonable, and within your power as the GM, to decide for your game.

As Game Master, it falls on you to adjudicate the rules. This means you're making judgments and decisions about the rules, especially when their application is unclear.

You have the ability to say using a low-grade silver longsword is viable "raw materials" for creating new silver weapons. Furthermore, there is real-world evidence (reddit) that weapons could be re-smelted, so it makes sense for this to be the case.

As an aside, it's worth noting that the only benefit to allowing this is "access to" the silver material. Silver, unlike some other crafting material is not Uncommon and "should" be available most places (this is, of course, up to the GM). Mechanically, the party is better off selling the equipment to the town guard or a smith looking for material and using that money to buy exactly how much silver they need due to Crafting's efficacy being nearly identical to other Downtime activities' income rates.
Comment: It may be worth adding that all this allows is access to the materials for Crafting. The ability to Craft has been nearly equated to other methods of gaining money. In practice, using looted weapons to Craft actually reduces their money and there is no reason not to sell the weapons and buy the material unless it is otherwise unavailable.
Comment: You may be interested in [my answer](https://rpg.stackexchange.com/a/161245/28326) to another question addressing how the benefit of Crafting is different in 2e than many other RPG's with it as an option.
Comment: Thank you @lfusaso. I believe I will accept that. My main concern was how to extract the precious materials (silver) from the other materials, but I will consider that they could have the same amount of silver used to craft the weapon.
Comment: I think I will use the rules for [formulas](https://2e.aonprd.com/Rules.aspx?ID=250) : "If you have an item, you can try to reverse-engineer its formula. This uses the Craft activity and takes the same amount of time as creating the item from a formula would. You must first disassemble the item. After the base downtime, you attempt a Crafting check against the same DC it would take to Craft the item. If you succeed, you Craft the formula at its full Price, and you can keep working to reduce the Price as normal. If you fail, you're left with raw materials and no formula..."


Why are ammonium ions reabsorbed in the thick ascending limb during acid secretion?

Question: In order to produce HCO3- from glutamine and to subsequently reabsorb it,
H+ ions need to be secreted. The kidney does this by via ammonium ions
in the PCT. But why are the ammonium ions then reabsorbed in the TAL before
being put back into the collecting duct? Wouldn't it be more efficient if
they were just left in the tubule fluid where they would reach the
collecting duct eventually? The first method seems to be a longer way of
achieving the same result.
Answer: Isn't it all to do with the reabsorption of water, i.e. everything gets flushed out in the Bowman's capsule and then some stuff is reabsorbed to lower the water potential of blood, so water is reabsorbed as well.
I guess I figured it was easier to have a leakier sieve at the Bowman's capsule than try to only release the waste products via facilitated diffusion.
Comment: but ammonium ions are secreted in proximal tubule before being reabsorbed in the thick ascending limb. From here they're pumped into the collecting duct to be excreted. But if they were just left in the tubule fluid (without being taken up in the TAL), they would've also reached the collecting duct.
Comment: I don't know the specifics of this pathway, it does seem convoluted, but it could be something along the lines of ammonium ions are reabsorbed during non-selective cation reabsorption, then selectively secreted. Again it's easier to take everything up then get rid of what you want to than try and take up just the things you want to. Edit, try looking at the transporters (ion channels/pumps etc.) involved.
Answer:
Why reabsorb $NH_4^+$ in the thick ascending limb if you're just going secrete it in the collecting duct

This is an excellent question. When you find an odd, seemingly inefficient aspect of physiology, it's an opportunity to learn something new.
This alternating secretion, reabsorption, and secretion starts to make sense when you look at the anatomy of the nephron.

There is no appreciable ammonia in the filtrate at Bowman's capsule (free ammonia is efficiently converted to urea in the liver by the urea cycle, so it's in very low concentrations in the blood).  As you say, it is produced in the proximal convoluted tubule. The amount that is produced is regulated by the acid load (more acid, more ammonia production). The proximal tubule is in the cortex (top of the photo).
$NH_4^+$ is in equilibrium with $NH_3$ in the tubule, and renal tubular cells and junctions are relatively permeable to $NH_3$ here, so the more $NH_4^+$ is produced and actively pumped into the lumen, the more $NH_3$ backflow leaves the tubule and enters the ECF. Because of this, the primary work of the PCT in acid base homeostasis by the kidney is not secretion (though $NH_4^+$ is actively secreted here), but rather in the production of new $NH_4^+$ and new $HCO_3^-$.
The bulk of the work of secretion happens in the collecting duct. There are a number of passive and active transport mechanisms for the secretion of $NH_4^+$ here, especially in the medullary collecting duct. These mechanisms are aided by a high concentration of $NH_4^+$ and $NH_3$ in the medulla (at the bottom of the picture).
So where does this high concentration of ammonia come from? It's from the reabsorption of $NH_4^+$ in the thick ascending limb. This is reabsorption (the tubular cells take $NH_4^+$ from the lumen and send it to the ECF), but you can think of it more as taking it from the cortex and putting it in the medulla. The filtrate flows along the lumen of the tubule, toward the collecting duct. Much of it is in equilibrium between the lumen and the ECF before it gets to the thick ascending limb. At the thick ascending limb, the permeability of the tight junctions and the tubular cell membrane changes. Solutes (the one we're interested in right now is $NH_4^+$) are taken out of the lumen and left behind in the ECF. Because the filtrate flows but not the ECF, and because the tubular cells are permeable before the thick ascending limb, and impermeable after, this substantially concentrates these solutes in the medulla, and dilutes the solutes in the cortex.
This is a process known as the countercurrent multiplier. The same principle is used to create a hyperosmotic ECF (and consequently, allow for a hyperosmotic urine if you've been wandering in the desert for hours).
Here's a diagram of the nephron from a decent review article that illustrates each of these processes for ammonia handling:


How to extract prosodic cues from a wav file using Python

Question: How do I extract the following features as from wav files in Python -

Voicing rate (Voice rate) - frequency of phonemes while speaking, and represents the pace of a conversation
Number of autocorrelation peaks
Pitch, pitch bandwidth
Answer: This project Speech Signal Processing Toolkit (SPTK) provides several features you are looking for. Here is a good wrapper around it https://github.com/r9y9/pysptk
This wrapper is using a slightly different version of SPTK, but installation is straightforward.
pip install pysptk
1) I would use kaldi or another speech recognition package on phones output and a VAD system to compute the voicing rate.
2) For autocorrelation, convert the waveform to mel-cepstrum with the function mcep then compute the autocorrelation with c2acr
3) Here is an example to compute the Pitch http://nbviewer.jupyter.org/github/r9y9/pysptk/blob/master/examples/pysptk%20introduction.ipynb


How does Different Chord Qualities work in Chord Progressions?

Question: I'm curious how different types of chord qualities affect chord progressions, for example:
Can an add9 chord be added into a C F G progression?
Comment: Is there something that prevents you from trying it out? If you try it and it turns out it isn't possible, your piano might explode because you attempted the impossible, or what? Or have you tried what it sounds like? How did the added notes affect your feelings? Did the added notes affect the perceived set of possible notes? Did it feel natural and true to the song's feel you're used to? How about melodies - did you try adding the extra notes to existing melodies?
Comment: I was wondering if there was a theoretical approach to it?
Answer: As others have mentioned, you can substitute any chord quality you like for any other chord quality, but since you've asked for a theoretical approach, here are some observations I've come to understand about this kind of substitution:
If you have a basic progression, you could substitute a major 6th chord for a major triad. You could do the same with an add9 chord for a major triad. I mention these two examples because they tend to really not have any effect on the underlying harmonic progression of the piece. Add9 chords, in particular, can be so subtle as to not be perceived by even some musicians (especially when voiced as an add2). They're a pretty "safe" choice of substitution. Most chords in a diatonic chord progression have the major 9th/2nd above the root (and for 6ths, all diatonic major chords have their major 6th available), so it'll usually sound pretty normal.
Now, in a more general sense, chord qualities can be substituted any way you like, but some substitutions sound different than others. Take your basic C F G progression. If I play a Cadd9 instead of a C, most people wouldn't really notice. If I played a C6 chord, they still might not really notice, but it might sound darker to them. If I played a Cmaj7 chord, they would probably notice that it sounds dreamier/jazzier. If I played a Cm(maj13♭9♯11), well, let's just say they'd definitely notice.
One of the most common places to substitute chords is on the dominant (G in our example). Instead of a G, I might play a Gsus. Or a G7. Or a G7♭9. You get the idea. Jazz, in particular, is a genre where lots of these substitutions occur, and they're often not so subtle :)
What's more, you don't have to only substitute out chord qualities. Instead of playing C Am Dm G C, I might play Em7 E♭°7 Dm9 G7(♯9♭13) C6/9. Some of those chords don't have the same roots as the chords they're taking the place of, but because they can fulfill the same harmonic function as the originals, they make sense in the new progression.
The best way to tell whether a certain substitution is something you like is to play it a lot and evaluate it. Maybe you like playing 12-tone matrices instead of actual chords. If so, go ahead. The gods of music theory aren't going to stop you. There are no hard-and-fast rules about what is "allowed", so whatever sounds good to you is valid. You can even add in chords between other chords, so long as you know what you're doing.
And finally, if you're playing in a group of people, make sure everyone's on the same page about what chords you're going to be playing. If the lead sheet says G7, then you might play G9sus while the guitarist plays G7♯11. That conflict may be too spicy for most audiences. And also: Don't just substitute because you know how - substitute when you think it truly makes the music better. You don't need to be throwing functional harmony out the window every time your friend asks you to play Wonderwall! :)
Comment: One thing that's useful with dense chords is that the more of a scale's notes you have, the quicker the chord can establish a new tonality. For example, you can jump to a different key almost arbitrarily by playing the new key's tonic as a m9 or m11 chord. Or maj9 or maj11 if you like major keys more.
Comment: @piiperi One thing I've always loved about big 13th chords is that you can modulate effortlessly with one fell swoop :)
Answer: If you apply some classical harmony, I think you can get a basic handle on the question.
In classical harmony chord qualities are: major, minor, diminished, and augmented for triads. The basic qualities of diatonic seventh chords are: major seventh, minor seventh, dominant seventh, and half-diminished seventh. Fully diminished seventh chords are a little different, but we can put them in the basic list.
With both triads and seventh chords it's the stack of thirds and their qualities that determine the chord quality.
In classical harmony, the different chords fit into particular functions within a key. Those functions are: pre-dominant, dominant, and tonic. You can read up on those separately, but I wanted to at least introduce the terms.
Your example is an add9 chord.
Technically an add9 is not a ninth chord. It is a ninth added to a simple triad. In classical harmony that ninth would be a non-chord tone. Not being a proper chord tone it cannot change the proper quality of the chord and if you don't change a chord's quality, you won't change its function. The chord will essentially function in the progression the same way.
However, if you change the chord in a way that changes a proper chord tone it will change the chord quality and potentially create a new function.
If you are in C major and change a plain triad C to C7, a dominant seventh chord, the function of the chord will change and it will create a different kind of harmony progression.
Some chord changes won't necessarily change function. For example in C major you can change the F major chord to F minor. The chord quality certainly changes, but the essential function of the chord will still be subdominant.
You can also treat chords in a non-functional manner, in which case all this discussion of chord quality and function becomes mute.
The sus and add chord types are the non-chord tone types which generally don't change quality/function. Other changes to proper chord tones can change the progression, especially if the change is to or from some kind of dominant chord.
So, my suggestion is when change a chord type ask yourself if that change results in a change of harmonic function.
Answer: Hope you're not asking what the 'rules' are!
The most used (and most accepted as) 'qualities' are major, minor, augmented, diminished and dominant. Other extensions, suspensions, additions aren't necessarily considered 'qualities'.
As we keep saying, do anything you wish - add extra notes to simple triads, move from X to Y, etc. No-one is going to have you lined up against the wall for it - although they may move out of earshot!
The most used quality will be dominant seventh, which is a ♭7 note added to a triad, making teh change up a 4th sound heralded. Augmented chords - where the 5th is sharpened, have the same sort of effect.
Diminished have the propensity to change tack completely, and move the line somewhere unexpected. Major/minr pretty well speak for themselves.
Your 'add9' can go pretty well anywhere - your choice - but hard and fast rules - don't bother! As piiperi says, give things a try - no-ones going to get hurt - and at the same time, give the lesser used chords - ♭5, ♯9, et al a sounding out.


Is it true that if supreme lord kills someone then she/he will attain Moksha?

Question: Moksha is the main goal of human life, people who do good karma attain Moksha.
Is it true that if supreme lord kills someone then she/he will attain Moksha?

The story of Pūtanā is an example
Comment: @DarkKnight https://hinduism.stackexchange.com/a/35398
Comment: Yes . Supreme lord only kills Demons, they attain moksha.
Comment: Not always, there are counterexamples for that....
Comment: @hanugm what are the examples.
Answer: Yes. Anyone killed by Lord gets Moksha. Lord awards Moksha to even people who hate and reject him. I will give few examples of people who got liberated from Bhagavatam.

These two associates of Lord Viṣṇu — Jaya and Vijaya — maintained a
feeling of enmity for a very long time. Because of always thinking of
Kṛṣṇa in this way, they regained the shelter of the Lord, having
returned home, back to Godhead.(SB 7.1.14)
My dear Prahlāda, O most pure, O great saintly person, your father has
been purified, along with twenty-one forefathers in your family.
Because you were born in this family, the entire dynasty has been
purified.(SB 7.10.18)
An effulgent light rose from Śiśupāla's body and, as everyone watched,
entered Lord Kṛṣṇa just like a meteor falling from the sky to the
earth.Obsessed with hatred of Lord Kṛṣṇa throughout three lifetimes,
Śiśupāla attained the Lord's transcendental nature. Indeed, one's
consciousness determines one's future birth.(SB 10.74.44-45)

Narada Muni explains the reason and purpose to reciprocate love with Lord and reach him.

By enmity or by devotional service, by fear, by affection or
by lusty desire — by all of these or any one of them — if a
conditioned soul somehow or other concentrates his mind upon the Lord,
the result is the same, for the Lord, because of His blissful
position, is never affected by enmity or friendship.(SB 7.1.26)
Many, many persons have attained liberation simply by thinking of
Kṛṣṇa with great attention and giving up sinful activities. This great
attention may be due to lusty desires, inimical feelings, fear,
affection or devotional service. I shall now explain how one receives
Kṛṣṇa's mercy simply by concentrating one's mind upon Him. My dear
King Yudhiṣṭhira, the gopīs by their lusty desires, Kaṁsa by his fear,
Śiśupāla and other kings by envy, the Yadus by their familial
relationship with Kṛṣṇa, you Pāṇḍavas by your great affection for
Kṛṣṇa, and we, the general devotees, by our devotional service, have
obtained the mercy of Kṛṣṇa. Somehow or other, one must consider the
form of Kṛṣṇa very seriously. Then, by one of the five different
processes mentioned above, one can return home, back to Godhead.
Therefore, one must somehow think of Kṛṣṇa, whether in a friendly way or
inimically.(SB 7.1.30-32)
Comment: thank you, for the nice answer.
Comment: Your most welcome @DarkKnight
Comment: Very nice answer with apt quotes from Narada Muni :)
Comment: Can you provide some verse that are clear about "lord killing people, and they  attain Moksha".
Comment: @DarkKnight Check SB 10.74.43-46 here : https://vedabase.io/en/library/sb/10/74/
It isnt allowing me to paste full
Answer: We have two contradicting views for this question, as per two different Purāṇas as follows:-
View 1: Yes, anyone killed by a Godhead will definitely attain Moksha.
While in Chapter 1 of Canto 7 in Śrīmad-Bhāgavatam Purāṇa, as explained by Nārada Muni, it is concluded that people killed by a Godhead will definitely attain Moksha, however, in the Skanda Purāṇa, we have verses which say contrary.
View 2: The people killed by a Godhead will only attain the worlds of Indra i.e., heaven.
According to Chapter 14 - Resuscitation of Dead Daitya,  Section 1 - Kedāra-khaṇḍa: of Skanda Purāṇa, those people killed in battle attain the world's of Indra (i.e.,  Amarāvatī / Swarga-Loka) only, and not the abode of the Godhead (Moksha).

तव युद्धं न दास्यामि नास्ति लोके स्पृहा मम ॥ ७.ख ॥ ये येऽसुरा हता
युद्धे अक्षयं लोकमाप्नुयुः । ब्रह्मणो वचनात्सद्य इंद्रेण सह संगताः ॥ ८
॥ भुंजतो विविधान्भोगान्देववद्विचरंति ते । इंद्रेण सहिताः सर्वे संसारे
च पतंत्यथ ॥ ९ ॥ तस्माद्युद्धेन मरणं न कांक्षे क्षणभंगुरम् ।
अन्यजन्मनि मे वीर वैरभावान्न संशयः ।
दातुमर्हसि मे नाथ कैवल्यं केवलं परम् ॥ १० ॥

"I will not offer to fight with you, I have no desire for worlds (and
worldly pleasures).

& 9. According to the words of Brahmā, those Asuras who are killed in
the battle will attain the Akṣaya (Everlasting) world. Immediately
they will come into contact with Indra. Enjoying various kinds of
worldly pleasures, they will roam about like gods along with Indra.
Then they will fall down to the earthly world.

Hence, I do not desire death in battle. It is of a momentary nature. O heroic lord, it behoves you to grant me Kaivalya (salvation)
alone, the great benefit, in the course of my next birth, of course,
as a result of an inimical attitude."

This view is supported by the fact that the Shudra - Shambuka, who was killed by Śrī Rāma, attained Heaven only, as per Chapter 35 - The Killing of a Śūdra Ascetic, in Section 1 - Sṛṣṭi-khaṇḍa of the Padma Purāṇa, and not Moksha.
Although, there's again an 'apparent contradiction' for Shambuka's fate as asked in this question - Did shambuka attain heaven?, because as per Padma Purāṇa Shambuka goes to heaven, but as per Uttara Kāṇḍa of Vālmīki Rāmāyaṇa, he won't attain heaven.
In any case, despite being killed by a Godhead, Shambuka didn't attain Moksha immediately, that's for sure, which supports our View 2.
Answer: No,no one gets moksha like that
Lord rama killed vali in ramayana, but he was reborn again because lord rama put a debt on himself ,that by killing vali wrongfully vali will be reborn to get that karma balanced.
This is the reasoning behind the deathof lord krishna who died by the arror of vali's reincarnation.
The laws of karma are not something lord can bend. If you wanna write citations than you can find argument in favour of the question and some against. But you must think for yourself too.
Many believe you will attain vaikuntha if you donate a cow because it is written in mahabharata and other smriti text but we know better about this.


Setting up a miner

Question: Before I decide to buy a miner, I wanted to know what I would need to get it up and running, such as cords, equipment, etc. I've got my eye on a $35.00 1.4 Th/s ASIC miner, and i'm hoping anything else i need will be less than $15. Thanks in advance.
Comment: $35 dollars sounds pretty cheap. Are you sure that offer is for an intact device?
Answer: $35 is a good deal, may be too good.
Well there are a couple of things I would recommend.

Somewhere to put your miner. Maybe an open-air rack? You really don't want it to be mining in the corner of your house.
Extra cooler? Maybe some external heat-sinks and a good fan you can aim at the miner
Your miner should come with power cables, etc. I wouldn't expect to need any. But if you're worried, ask the seller if the miner comes with cables.
If you really want, a solar panel if you don't have one already. Doesn't have to be solely for your miner, you could use it as a long-term investment :)
Comment: Now that I'm looking at the product, it says it is a 1.4T ASIC miner. Is "1.4T" just the name, or is it the hashpower?
Comment: Not really sure. You'll have to mine to test out. Usually is should be rated at "1.4 TH/s, not 1.4T. If it doesn't say the speed anywhere else however, this will probably be the speed.
Comment: I'm not sure, because in the title, it says not only 1.4T, but later in the title it says 300G. It's really confusing.

Setting up a miner


implement push notification in firebase with batch

Question: I am trying to make  firebase and batch work together so that I can fire push notification when something in firebase db got changed. I followed this tutorial  and now i want to make them work automatically and for that i contacted with batch's and they replied me

write your own server-side code to 1. detect Firebase db changes 2. call the Batch API.

For  "detect Firebase db changes" I have to create a server-side code  which will track changes and call batch's api accordingly. Then follow this documentation for attaching the changed content and send it to appropriate user.
I don't know how to create the server side code. Anyone can give me a quick instructions on it or there's any tutorial related to this?
Answer: To write server-side Firebase code you can use the node.js SDK. See https://www.firebase.com/docs/web/quickstart.html (search the page for node.js).
The API is exactly the same as the regular web API except that you'll be writing it as a node.js application that can be run on the server. You can then integrate this with Batch's API.
Comment: hey man thanks a lot for your quick response , let me check your link :)


Why is the cyclopropenium ion aromatic?

Question:
I don't understand how the 'cyclopropenium' ion is aromatic. According to my understanding, the carbons within the central 3 carbon ring must each be sp2 hybridised with a single electron in a p orbital - since each carbon is bonded to 3 other atoms and has 4 valence electrons. How does that lead to aromaticity, since this doesn't fullfil Huckel's rule?
Comment: Related: [What is the reason for the exceptional stability of tricyclopropyl-cyclopropenyl carbocation?](https://chemistry.stackexchange.com/q/85046/41328)
Comment: https://en.wikipedia.org/wiki/Cyclopropenium_ion#Bonding
Comment: https://en.wikipedia.org/wiki/Aromaticity.
Comment: It's because the of the small size of the molecule. The hydrogen on the cation does not interfere with pi electrons orbiting around the cyclic molecule.
Answer: It does meet Huckel's rule.  When you have $m$ carbon atoms in a conjugated ring with a positive charge of $q$, there are $m-q$ pi electrons.  Here $m=3, q=1$ therefore the number of pi electrons is $m-q=2=4×0+2$.
A Huckel model calculation indicates that cyclopropenyl cation has roughly as much stabilization as benzene, but it's distributed over three instead of six carbon atoms.  Thus aromaticity is especially powerful in a cyclopropenyl cation ring.   This explains how a positive (formal) charge can be stabilized on as few as three carbon atoms and the ring holds together despite steric strain.
Comment: Thanks very much Oscar, I supposed i overlooked the positive charge. You mention how stabilization is distributed over three carbons instead of six, are you referring to the positive charge?  Am i right in thinking that in general a larger distribution of charge lead to greater stability?
Comment: I am comparing the pi-electron stability based on the "Frost circle" which is a picture of the Huckel model) versus ordinary valence bond structures.  Benzene gives a difference equal to one "extra" pi bond in this model.  Cycylopropenyl cation gives that amount of stabilization too, but each ring atom gets one third of it not one sixth.  That bigger per-atom stabilization helps stabilize the charge and fight steric strain.
Answer:
the carbons within the central 3 carbon ring must each be sp2 hybridised with a single electron in a p orbital

This is incorrect.
The requirements for Huckel aromaticity are:

There must be a continuous, planer ring of overlapping $p$ orbitals.
There must be $4n+2$ $\pi$ electrons in the system.

The cyclopropenyl fulfills these requirements because it is planar, has overlapping $p$ orbitals, and has 2 $\pi$ electrons ($n = 0$).
Answer: The cyclopropenyl cation is aromatic because it is meeting all the definitions of Huckel's rule of aromaticity:

All carbons are sp2 hybridised.
There are 3 carbon atoms which form a conjugated system and moreover it has a positive charge therefore it has $3$-$1$=$2$ pi electrons.
If we put $n=0$ in Huckel's expression ($4n+2$) pi electrons we are getting 2 as the result.
The cation also has overlapping planar and parallel p orbitals. You may be knowing that for maximum overlapping, orbitals should be parallel to one another and planar.

Since the required criteria are fulfilled, it is aromatic.

Why is the cyclopropenium ion aromatic?


What are some alternatives if you don't have a flip screen in your camera?

Question: I have a dslr camera which does not have a flip screen. So in situations where i want to take a shot from very low angle, It is very hard, compared to the flip screen available situation. Is there any tips or tools which helps me to handle this situation ? May be i can connect my camera to my phone and use the phone as the screen with the help of some app ?
Comment: The make/model of your camera would allow answers to be more specific to your situation.
Comment: Lie down on the ground and shoot up. I agree it's a pain to do that but that's how people have been doing it since cameras were invented.
Comment: For me the flip screen is one of the best innovations in cameras of recent years. There are tons of pictures I would not have made when I would have needed to use any additional gear. Cause the flip screen is always with me and applicable immediatly. And after four years, including 7 months travelling in sandy environments, the flip screen on my Canon 70D is still working like new.
Comment: If the camera has a HDMI port or similar you can attach a small monitor and use that.  I do not know of a phone that supports HDMI-input.  If the camera can be remote controlled either tethered from a laptop or remotely from your phone that would be an option as well - that works for my Canon 70D,
Answer: You could consider a right angle viewfinder.

They just clip onto the viewfinder where the little rubber eyepiece goes. Generally they rotate left and right a bit to give you a bit of flexibility in how you position yourself, and you get to physically see through the lens which can be better than using the live view image on a screen.
As someone else suggested, a mirror would give you similar results for considerably less.
Answer: The flip screen, usually called rotating screen is a liability. Even tilting screens are more fragile than a fixed one, so your camera is tougher for the matter. This constraints flexibility of composition but it is usually easier to keep things level when using the viewfinder, even if you have to crouch. There are a few things you can do to help with that:

Get a low tripod or Gorillapod to help set the camera low. This will make it easier for you to get into position since you don't have to hold the camera too.
Use Live-View since most rear LCDs have now a wide angle of view, you can still see what is in the frame from above and to the side.
Buy a secondary monitor. This usually connect via the HDMI port and show you Live-View on a much larger screen which is positioned on an articulated arm.
Use WiFi if your camera has it. Many modern cameras have WiFi feature which will stream the Live-View into a smartphone or tablet. This is infinitely more flexible than a rotating or tilting screen yet does not make your camera more fragile for the matter. I hope that as this feature becomes more common, we will finally see an end to movable displays.
The final option is to use some type of tethering software. They can sometimes show the preview or at least image review but you must have a computer connected to your camera. I don't think a tablet or smartphone version has been created yet.
Comment: DSLR Dashboard is an Android app that does tethering.
Comment: You can use an app like DSLR Controller on Android along with a USB cable+adapter to connect many Canon cameras to your phone or tablet and use it as a second screen. I believe similar options exist for other brands.
Answer:
What are some alternatives if you don't have a flip screen in your camera?

Practice until you become familiar enough with your camera and lenses to be able to "shoot from the hip" with a reasonable expectation of success.
Not every camera that has been used effectively in the past had a way of seeing the exact scene immediately prior to taking the image. Many historically and artistically significant images were made without a real time view of the camera's field of view. Even focusing was a guessing game assisted by aperture and distance scales on lenses.
The next time you watch the end of a major sporting event or the circus outside a courtroom as a high profile personality is going to or from the trial look at all of the news pros (stills and video) in the shoulder to shoulder crowd shooting blind with their cameras held high over their heads. Very few of the still cameras have movable screens because not only are the screens themselves more fragile but they also make it more difficult to seal the camera body from weather and other harsh environments.
Start with the widest angle lens you have and go from there. Experiment with different AF modes and selected points to see what works for a particular type of composition. You'll be surprised at how proficient you can get at it with a little practice!

Are they counting on just luck to help them? If you rapidly shoot 1000 images you are going to get a few good ones?

"Luck is what happens when preparation meets opportunity." - American football coach Paul W. "Bear" Bryant upon being asked why his teams seemed to have better luck than his opponents in close games.
Practicing something enough until it becomes an acquired skill and enables one to get a "lucky" shot when the opportunity presents itself seems to be beyond the grasp of many today. Too many people are quick to dismiss anything that they don't understand or that they can't duplicate as "fake" or "blind luck."
In "pre-digital" days you only had 24/36 frames until your "buffer" was full for a 35mm SLR. You had even less if you were shooting 120 format roll film in a Speed Graphic. Nobody shot 1000 images of anything. Sure you may take a couple of extra safety shots, but you had to learn how to point the camera without having your eye glued to the viewfinder.
There were, however, motor winders that attached to the bottom of the camera that allowed shooting at a blazing 2 fps! And you could get a film back that could hold a roll about 100 shots long. But those things were way too heavy and bulky to use free hand over the head.
I was at the end of the field shooting a high school band warming up for their halftime show at a football game last fall. Just as the band departed their warm up area past the end of the field the game action moved to that end of the field. I shot a few plays from well past the end line to get the framing I wanted as one of the teams tried to drive down the field before halftime. (My band was the home team and would be the second band to perform following the visiting band, so I had some time to spare.)
I got this frame of a long pass attempt being broken up at the goal line:

Here's a friend of mine shooting the football game for a local newspaper. (He's had hard news images published in the NY Times. He's had a photo essay shot entirely on a smartphone about small town youth league baseball published in ESPN the Magazine.) When the play started the line of scrimmage was 30-40 yards up the field from his shooting position so he was shooting with a long lens. As the play developed and a pass was launched to the side of the end zone right in front of his position he put down his long body and began raising his wide angle body just in time to catch several frames as three players and the ball arrived simultaneously. The shot he grabbed a split second after the time I captured the image below was published as the lead image on the sports page in the next morning's print edition that went to press barely an hour after this happened. (Yeah that's me way in the background.) He still didn't have the camera up to eye level in my frame taken after the shot published at the link above. In the online photo gallery for the newspaper's coverage of the game he published a total of four images (#'s 1, 2, 11, and 12) captured between the time the football was knocked away (as shown from a different angle by my first image above) and when the ball hit the turf barely one second later (my first image is timestamped 20:04:39, my last image is timestamped 20:04:40).

I've seen him do this more than once. I've also seen the results. If I were a betting man I'd say he nails such a shot much more often than not. He is now the Director of Photography for the Tuscaloosa News and shot their coverage of the last half of the University of Alabama's march to a football national title in January of 2016. That was the sixth college football national championship game he's shot in the last eight seasons (4 covering Alabama, 2 covering Auburn).

Was such blind shooting the norm in pre-digital days too? That would have taken a lot of skill if focus was manual & due to a lack of burst mode shooting you'd only get a few blind shots. Especially if you must manually advance the film after a shot.

Some cameras had no way to see through the lens prior to taking the shot. A cursory viewfinder was attached to the side of the camera or, if you had a deluxe model, to the front standard that held the lens. No accommodation was made with such viewfinders for lenses of varying focal length. The photographer just had to know how wide the angle of view for the lens being used was. Focus was set by estimating or measuring the subject distance and lining up a mark on the lens to a scale with that distance. Aperture and shutter speed were also set manually with no metering built into the camera. Some of those cameras used roll film with anywhere from 6-12 shots per roll. Others used sheet film that had to be changed after every exposure. The latest versions of such press cameras were still being used by local press photographers in my hometown as late as the early 1970s.
Comment: "Luck is when preparation meets opportunity." Practicing something enough until it becomes an acquired skill and enables one to get a "lucky" shot when the opportunity presents itself seems to be beyond the grasp of many today. Too many people are quick to dismiss anything that they don't understand or that they can't duplicate as "fake" or "blind luck."
Comment: It's amazing how skill and practice can make someone look consistently "lucky".
Comment: Re the news pros: Are they counting on just luck to help them? If you rapidly shoot 1000 images you are going to get a few good ones? Was such blind shooting the norm in pre-digital days too? That would have taken a lot of skill if focus was manual & due to a lack of burst mode shooting you'd only get a few blind shots. Especially if you must manually advance the film after a shot/.
Comment: In "pre-digital" days you only had 24/36 frames until your "buffer" was full. Nobody shot 1000 images of anything. Sure you may take a couple of extra safety shots, but it's called learning how to point the camera without having your eye glued to the viewfinder.
Comment: There were, however, motor winders that attached to the bottom of the camera that allowed shooting at a blazing 2 fps! And you could get a film back that could hold a roll about 100 shots long. But those were way too heavy and bulky to use free hand over the head.
Answer: Compact mirror (as in makeup mirror) can be used for viewing from difficult angles, e.g. close to the ground. You can hold it in place with tape made to be easily removed. Duct tape is not advised, though approved by Possum Lodge.
Answer: Yeap you can use a wi-fi card like eyefi. But they send the signal when you take the photo.
Depending on the camera there are some adapters that could send live view images. For example: http://www.nikonusa.com/en/learn-and-explore/article/h4spl2xm/shooting-wirelessly-with-nikon-digital-cameras-and-wi-fi-adapters.html
Comment: But it still could be useful, if the camera is fixed in position, ie on a tripod. You could take a photo, check if it is correct, then adjust the camera as necessary. Not as easy as using the screen or live view on a phone, but better than nothing.
Comment: Seeing the image after you take the photo is very different from using the screen to compose a shot before you take the photo.
Comment: "Depending on the camera there are some adapters that could send live view images"
Answer: As there is the software-recommendation tag:
I have used (q)DslrDashboard to remote control different Nikon DSLRs.
Reviews on the Android store suggest mixed results, but I successfully used it both from Android devices and my Windows laptop. WiFi connection was provided by a TP-Link MR3040 router with a custom Firmware that can be downloaded from the DslrDashboard website, plugged into the camera USB port.
It depends on the camera firmware which functionality is available (ex. no start/stop of video recording on my entry-level D3200, but working flawlessly on a D5300). Live preview and still image capture worked even on the D3200.
(Not affiliated, only used it a few times.)


Bitcoin payout based on real-life event

Question: Just starting to learn bitcoin scripting. Can someone explain how to pay out based on some real-life event?
I currently test from the command line with bitcoind -regtest
Comment: Have a trusted server monitor the real-life event, then make it send the payment when it happens.
Comment: There isn't one - that's intentional. If it allowed an outside oracle, that oracle might tell one part of the network that the transaction is valid, and tell another that the transaction is invalid.
Comment: Could you clarify what you mean by conditional? When I use a normal [transaction script](https://en.bitcoin.it/wiki/Transactions), it includes two conditional statements: `OP_EQUALVERIFY` and `OP_CHECKSIG`.
Comment: @NickODell That seems to be a good start for an answer. :)
Comment: In most simplest form, if a condition is met by checking an outside "oracle", then pay out, if not then do not pay and continue to check until condition is met.
Comment: So how would one go about a conditional script which relies on a real life event to trigger a payout?
Comment: I am awaiting the Murphy answer like a school girl
Comment: You could use a service such as ifttt or tasker to tie in BitCoin API with a real-life event monitoring service.
Answer: Bitcoin can't directly check the outcome of real-life events. However, it is possible to make conditional transactions with the help of third parties. This can be achieved with multisignature addresses. A multisignature address is an address which is controlled by several different people. To spend the money from such address, signatures from specific number of those people is required. For example, to spend from a 2-of-3 multisignature address, at least two of the three owners must agree on a transaction.
How can this be used to make conditional payments? Well, there are three parties: the sender, the recipient and the party which determines the outcome of the event, which we will call the oracle. The oracle provides a public key which corresponds to the event which is the condition of the payment. If the event happens, the oracle would reveal the corresponding private key, so anyone would be able to use it to make signatures.
Now, suppose that the sender sends his money to a 2-of-3 multisignature address with the owners being himself, the recipient and the public key provided by the oracle. Until the oracle reveals his private key, the recipient can only spend the money with the assistance of the sender. Afterward, the recipient can use the key revealed by oracle to spend the money as he wishes.
This scheme, however, has a few problems. Firstly, if the event doesn't happen, the sender can only take his money back with the assistance of the recipient. Secondly, if the event does happen, the sender can take his money back if the recipient is not fast enough to move it first. The first problem can be solved by having the recipient sign a transaction returning money back to the sender before the sender broadcasts the first transaction. Here is an example of how this feature can be used. The second problem can be solved by using more complex script than 2-of-3. For example, it is possible to make a script which lets the money to be spent by sender+recipient and recipient+oracle, but not sender+oracle.
By the way, when doing research on this question, I found an actual website which offers to reveal private keys based on the outcome of real-life events.

Bitcoin payout based on real-life event


Which image is shown ontop whilst mosaiking with the FME Rastermosaicker?

Question: I have two Images which overlap and I want to mosaic the two images. One of the images has nodata values in this overlapping area and the other does not. I obviously want the overlapping area to be image data and not nodata values but how do I define which data gets written to the output file? In ArcGIS one can set either match, last or first. But I don´t see a similar option with FME2014.
Answer: The order of the input features determines the order in which rasters will be drawn. The first raster to enter will be drawn first, then each subsequent raster will be drawn on top of any previous overlapping rasters.
In this case the nodata raster should be first. You can use a Sorter transformer to enforce the order in which the features are processed, or change the order of the Readers in the Navigator window.
Comment: Just came across this answer and wanted to add that there is an update in FME2017 where you can get to choose the order of overlap in the Mosaicker transformer itself. You can choose to take the first cell, or the last cell, or the minimum, maximum, average, or sum of all cells.


Is there a way to disable composite effects on already rendered frames?

Question: I rendered about ~170 frames with the glare node on and would like to look how the normal render looks without rendering those frames all over again.
Comment: Unless you saved the images as frames (or other format) before post processing, there is no way. You will need to render again.
Comment: That's unfortunate. Thank you for the answer.
Answer: Unless you saved the images before post processing, there is no way: once an image has been processed, flattened and saved into an output format, you can't de-construct it and revert it to a previous stage.

You will need to render again.

But before you do that please read on.
As a piece of advise: you can use a file output node to save each frame as is being rendered before post processing.
Also never render an animation as video. Render an image sequence and encode later.
If you care for quality use OpenEXR as the render format. That way you can keep your information, and passes undistorted and linear.
There is a reason why Post-production exists. If you have saved all of your frames before any effects, then you can brig those rendered frames into the compositor and experiment different looks and effects in a non-destructive manner, without having to re-render the original rendered layers every single time.
Rad: Is there a way to export each rendered layer as its own image?
 and How can I render all render passes to files in Cycles?


How can I differentiate between the pronunciation of "w" and "v"?

Question: This something may be innately obvious to native speakers; however, to many outsiders, the difference is elusive. I only recently realized the difference and still have a hard time to distinguishing them. Please explain how to pronounce these two letters correctly, specifically lip/tongue movement (no pun intended).
Comment: I have noticed that Swedes have a tendency to mix up V and W a lot. Might be related to the fact that the W has almost disappeared in modern Swedish and that both letters are pronounced the same way. I am curious -- what other nationalities have a hard time distinguishing the two sounds?
Comment: Related: [Correct pronunciation of the letter "v"](http://english.stackexchange.com/questions/23830/correct-pronunciation-of-the-letter-v).
Comment: Note that words from other languages may have different rules for the pronunciations (especially of W).  For example, 'cwm' in Welsh, or Weimar or [Wolfgang](http://inogolo.com/pronunciation/Wolfgang) in German.
Comment: @Anderson If you make the 'v' sound correctly and hold it, it should sound like a bee buzzing - ask a native speaker to show you what I mean.
Answer: W:  With your tongue at rest (not touching teeth or lips, etc), pucker your mouth into a small "o" as if you are going to whistle (only not quite so hard, or it will tire you out), and let your voice take over.
V: With your tongue at rest, pronounce a voiced "ffffff" sound.  My enunciation of this proceeds by putting my top teeth against he inside of my bottom lip and blowing.  I voice it for a "v" sound, meaning that my vocal cords vibrate making for a noisier, louder sound..
I realize that different people pronounce it differently.  For the record, I am a native American-English speaker living in Pennsylvania in the United States.  (Not a native American, to be sure.)
Comment: @Marcin: That's what I meant by "voicing".  And yes, I agree that the tongue is slightly further forward and relaxed for the "V".
Comment: I would put my tongue slightly forward for a 'v' sound. There's also a lot of lot voice-box vibration in addition to the blowing.
Comment: Explaining pronunciation without the use of phonetic terms is like baking a cake without a recipe for the first time.
Comment: @Harrold: As an amateur phonetics enthusiast, I've been through all the ins and outs of language phonetics, much like Professor Higgins - on a smaller scale, you understand.
Answer: Take a look at these interactive phonetic animations. Sadly, I am not aware of any similar that feature British English, but if you choose American English, you will gain access to an excellent resource of phonetic animations with sound and frontal videos of people during pronunciation, sorted according to the International Phonetic Alphabet (IPA). V is the voiced labiodental fricative (consonants –> place –> labiodental –> /v/) and W is the voiced labiovelar approximant (consonants –> place –> bilabial –> /w/). You could also choose to see the process explained chronologically. I do not think that there is a better explanation, really.
Comment: For British English, this video produced by the BBC, explains the difference: http://www.bbc.co.uk/worldservice/learningenglish/grammar/pron/sounds/con_other_7.shtml
Comment: +1 for the awesome link.  Sad there is no British English but it's very similar to American anyway.
Comment: For 'w', do you mean labiovelar or bilabial? I've always thought it the latter, but wikipedia seems to say labiovelar. Now the question is why those two are so easy to interconvert/mistake?
Comment: @Mitch A bilabial consonant is formed by at least a partial closure of the lips and the term labiovelar in this case means a _labialised  velar_. In English, /w/ is a complex consonant with secondary articulation. Notice how its pronunciation starts with the proximal part of the tongue almost touching the soft palate and then moves down and slightly forward, followed by labial movement. The absolutely correct term for /w/ would be the _voiced labialized velar approximant_.
Comment: @Otavio Macedo -you should post that as an answer as it's by far the clearest example.
Answer: Turning my comment into an answer:
For British English, this video produced by the BBC, explains the difference: http://www.bbc.co.uk/worldservice/learningenglish/grammar/pron/sounds/con_other_7.shtml


Help troubleshooting single phase motor

Question: I have a single phase 230 volt motor.  I am getting 230 volts (115 at each terminal marked with the red line in the image below).  The motor is not drawing any amperage at all and is making no noise at all. The centrifugal switch looks okay. Can it be the start capacitor?  I was under the impression that if the start capacitor was bad it would still pull amperage.  What can I test next to help determine why the voltage is not ultimately getting to the the windings?
Comment: Is there a broken wire somewhere or even a thermal cutout - you may be lucky some are re-settable others need replacing...
Comment: I'm not sure.  I'll try to find an electrical diagram for this motor online somewhere.
Answer: If it's new, never has run before, you might have both the terminals you indicated connected to the same phase
You say that both are at 115, as they should be. Have you measured 230 volts between them?
Comment: But along those same lines, if your 230V comes from two separate breakers that do NOT have a common trip, one breaker can trip and the other one stays energized. You will read 115V on both terminals because inside of the motor, they are common to each other and you are reading the SAME 115V circuit right through the motor windings themselves. With the motor not spinning, there is no impedance, only the resistance of the wire and that's very very low. So again, read the voltage BETWEEN the two terminals, not one at a time. If it reads zero or some very low value, that's the problem.
Comment: Thanks John.  The motor ran just fine a couple of weeks ago.
Answer: A single phase AC motor has two windings. the main winding and the secondary winding to help starting the motor. The auxiliary winding is switched in series with a capacitor and possibly a centrifugal switch.
In your case the main winding can be found by measuring the resistance (relatively low). The auxiliary winding can be found in the same way and should have a higher resistance. If you have more connections a thermal protection might be there also and could be defective or needed a reset.
Once both windings are found you have to make sure that the auxiliary winding is in series with the start capacitor and the centrifugal switch. The centrifugal switch is normally closed and opens when the motor speed is high enough to switch of the auxiliary winding.
When connecting the motor back to the mains there should be a current flowing
through the main winding and the motor should start to run if the auxiliary circuit is also ok.
So first verify the all the connections and make sure they are ok. From there you should be able to proceed.

Help troubleshooting single phase motor


Are black holes an infinite source of energy?

Question: Black holes are considered particularities because in a determined point in time they are pointless, as consequence there are some mass in a null space so the density become infinite. Finally if energy is equal to mass, that is mean a black hole has an infinite energy? Is that possible?
Comment: Infinite density does not mean infinite mass. Black holes have a finite mass, see http://physics.stackexchange.com/q/25802/
Answer: No, the energy of a black hole is not infinite. It depends on its mass, angular momentum and charge. Infinite density at a point does not translate to infinite energy in the $E=mc^2$ sense.
It is in fact possible to extract energy from black holes by exploiting certain properties of accretion disks or ergospheres, but this is a finite process.
Answer: The problem with this is that $$E = mc^2$$. Density, however, is given by $$density = \dfrac{mass}{volume}$$
Thus, if volume = 0, then density is infinite. Black holes have a finite mass. It is there density which is finite because all the mass is at a single point (singularity, volume = 0).


How can I use my built-in AMD Radeon 7670m instead of Intel HD 4000 Graphics?

Question: i recently bought a DELL Inspiron 15R 2012m Series Laptop. It comes with a built-in AMD Radeon 7670m graphics card.
I installed PES 2012, when I checked the system specification (an option in that PES 2012 game ). I came to know that game runs with Intel HD4000 Graphics and not with my AMD card.
I also changed the swithchable graphics and assigned High Performance to PES2012, but the game still runs on Intel HD4000.
Answer: You must uninstall the AMD driver with Catalyst program and after this, install Catalyst 12.7 beta. This worked for me.


Can you use the word "cochonnerie" as nonsense?

Question: I know that this is used for junk food, but can you also say "Il dit des cochonneries ?" as in what he's saying is total nonsense?  or is there another translation or is it simply not used in with parler or dire...?
Comment: I won't add an answer, the previous ones are great. I will just add two correct expressions that can replace your expression: *il dit des bêtises* and *il dit des sottises*.
Answer: About the use of "cochonneries"
In my experience (I'm from Quebec, Canada) :

Il mange des cochonneries

is used to expression someone eating junk food.

Il dit des cochonneries.

is not used to express nonsense, but is used for sexual related stuff. This can also be used with the verbe "faire" to express the action, instead of just talking about it.
So, people might (and probably will) misinterpret you if you use it to describe nonsense. And that could get you to some awkward situations!

What would be a correct expression
As far as I'm thinking I don't really see any expression to tell people that what they say makes no sense but something like

Ça n'a aucun sens ce que tu dis!

Which is very litteral.
Actually, there would be a very "street-y" expression to mean nonsense :

Tu dis de la merde!
Comment: Your description of the usage of *cochonneries* also applies to France.
Comment: @Gurney: It applies to France as well. I guess you are not "street-y" enough :-)
Comment: I agree with Gilles. But "tu dis de la merde" is definitely from Quebec. Here the common expression is "tu dis des conneries" (slang) or "tu dis des bêtises".
Answer: Cochonneries describe multiple things in the french language:

junk food
trash, rubbish, dirty objects and things
sexual activity, as in faire des cochonneries
dirty talk, as in dire des cochonneries
Answer: Make cochonnerie a bit shorter, and you can use it :)

Tu ne dis que des conneries

If you want to use the verb parler, you could use the following expression

Tu parles pour ne rien dire
Answer: On top of Hugo Dozois's answer, I would translate what he's saying is total nonsense as follows:
Formal:

Ce qu'il dit est dénué de sens. (this one is really formal)
Ce qu'il dit n'a aucun sens.
Ce qu'il dit n'a pas de sens.

Unformal:

Il dit n'importe quoi.

Derogatory/colloquial:

Il dit des conneries.
Il dit de la merde. (this one is worse than the previous one)

Can you use the word “cochonnerie” as nonsense?


How would a herbivore's digestive tract differ from a human's?

Question: How would a herbivore's digestive tract differ from a human's? What are parts (organs, tissues, etc.) or enzymes that can't be found in one but is in the other? Also, is it correct to say that a herbivore's digestive tract would be more complex than a human's because herbivore diets tend to  contain a lot of complex carbohydrates to digest?
Comment: it's a bit of simple quesiton... you would have such a more studied answer if you just look at cow digestion online. For one, vegetarianism requires a longer digestive tract, i.e. 5 stomachs and bigger intestines. and they have different intestinal flora than specialized animals of all other kinds. https://en.wikipedia.org/wiki/Ruminant#Ruminant_physiology
Answer: It depends on the method of digestion the herbivore utilizes and what they eat, grasses, leaves, fruit, or nuts . Ruminants are only one form of herbivore. A wonderful introduction to the various methods can be foundd here. http://vetsci.co.uk/2010/05/14/comparative-digestion/#
For comparison gorilla which are far more herbivorous than human have a much longer small intestines which is one reason they need a much wider trunk. They also of course need larger teeth with thicker enamel and much larger jaw muscles to chew the tough plant fibers. Not so much more complex digestive systems just bigger/longer.
Comment: Cutting/pasting an entire answer is not a good way to answer a question on any SE site. Please look at the answers section of the help section.
Comment: Good point let me fix it.
Comment: Happily removed my DV and replaced with an UV.
Answer: Herbivorous animals certainly tend to have very different digestive tracts to humans, or other carni-/omnivores.  In general, mammals cannot produce enzymes that will digest cellulose, so if an animal is to use cellulose as an energy source there must be another way of extracting its energy.  Principally, this is fermentation.
Fermentation is the process of bacterial breakdown of a sugar-like compound to other molecules, such as gases, acids or alcohol.  Herbivores provide an internal environment that is hospitable to cellulose-fermenting bacteria, and provide them with cellulose (by eating plants!).  They then use the breakdown products of fermentation as an energy source - often the relevant compounds are volatile fatty acids.
Different species have solved the problem of having an internal fermentation chamber in different ways.  Cattle, as many people are aware, have a complex and expanded foregut, and regurgitate their stomach contents to allow further mechanical digestion.  Horses have a vastly expanded hindgut (caecum and large intestine).  Rabbits have an expanded hindgut, and also eat (certain types of) their droppings to allow further mechanical digestion.
One other difference that we can observe in herbivores is in the structure of their teeth.  A carnivore such as a lion will have sharp, pointed teeth and a wide opening jaw to allow catching and killing prey, and tearing of flesh.  Herbivores have broad, flat teeth with rough occlusal surfaces to allow efficient crushing of prehended food.  They may also have adaptations for dental longevity - the horse, for example, has hypsodont or long rooted teeth, that erupt through its lifetime to combat the wear of extended chewing of rough material.
Comment: Welcome to SE Biology. This answer would be improved with some links that confirm your main points. Irrespective, +1 from me.
Comment: 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.
Answer: The digestive tracts of ruminants (cud chewers) such as
cattle, goats, and sheep are specialized to maximize the benefits
of their endosymbiotic microorganisms. In place of the
usual mammalian stomach, ruminants have a large, four chambered
organ.
The first two chambers, the
rumen and the reticulum, are packed with anaerobic microorganisms
that break down cellulose by fermentation.
The ruminant
periodically regurgitates the contents of the rumen
(the cud) into the mouth for rechewing. When the more thoroughly
ground-up vegetable fibers are swallowed again, they
present more surface area to the microorganisms for their digestive
actions.
The microorganisms in the rumen and reticulum metabolize
cellulose and other nutrients to simple fatty acids, which
become nutrients for their host.
The food leaving the rumen carries with it enormous numbers
of cellulose-fermenting microorganisms. This mixture
passes through the omasum, where it is concentrated by water
absorption.
It then enters the true stomach, the abomasum,
which secretes hydrochloric acid and proteases. The microorganisms
are killed by the acid, digested by the proteases, and
passed on to the small intestine for further digestion and absorption.
The rate of multiplication of microorganisms in the
rumen is great enough to offset their loss, so a well-balanced,
mutually beneficial relationship is maintained.
It would be more correct to say that Herbivores have special adaptations for digesting cellulose rather than complex as humans also have a complex digesting system.
Hope that helps you.
Comment: "The rate of multiplication of microorganisms in the rumen is great enough to offset their loss, so a well-balanced, mutually beneficial relationship is maintained." -- well that's how it should work - in modern farming feeding practices often result in derogation of the rumenal bacterial population.


Can I connect two bluetooth device to my tablet?

Question: I would like to connect a bluetooth keyboard and bluetooth mouse to my tablet. Is it possible at the same time?
Comment: This depends on solely on the device and the Bluetooth antenna. Bluetooth works similar to WiFi (talk/air time, MAC addresses etc.) so usually you can connect multiple devices to a single host. Have you tried connecting multiple devices at once?
Comment: There may be a long answer as well, but your question is vague as you don't specify the devices you are using. What tablet? What mouse and keyboard? There are very few devices (mostly just headphone hubs) that can support multiple simultaneous connections.
Comment: please consider adding further informations ,like tablet model ,android version
Comment: The tablet is an [ASUS MemoPad HD 7](http://www.gsmarena.com/asus_memo_pad_hd7_16_gb-5492.php) and runs the factory android 4.2. I would like to use a case with bluetooth keyboard and if it is possibel i want to buy a bluetooth mouse too.
Comment: Hey OP- don't forget to select an answer below if it helped. Thanks!
Answer: I honestly thought that only one device could be connected at a time using Bluetooth. In an attempt to prove my point I tested connecting multiple devices simultaneously to my Samsung Galaxy Tab 4:

Sure enough I was able to stream music to my Milwaukee speaker while using an Apple mouse and keyboard- all connected at the same time. Granted, there are probably still instances where this might not work depending on devices and most likely would only be able to stream music to a single device, but it worked perfectly in this case.
Comment: That's not true. One master (tablet or smartphone) can communicate with up to 7 slaves. You can easily be connected to a smartwatch and headset/car at the same time.
Comment: @Alex You are only partly correct, especially when considering the hardware in question. The ASUS MemoPad HD 7, as the OP eventually informed, has Bluetooth 4.0. The specs on most devices using Bluetooth 4.0 use dual-mode radios. This essentially does allow the phone/tablet to be connected to two Bluetooth devices simultaneously, but only certain devices. The dual-mode radio allows connection to one Bluetooth 4.0 low-energy device, for instance your smartwatch, and one "classic" device like a headset. This seems to be the limit. However, I will test this theory later today myself to make sure.
Comment: @Alex.S - I stand corrected and changed my answer accordingly.
Answer: Certainly on my phone I have two Bluetooth devices connected simultaneously - my watch and headset.  It really depends both on the host device (the tablet) and to some extent on the  peripheral ie the mouse and keyboard.


Is it possible to sell voting rights?

Question: Let's say I own some stock but don't care about the voting rights at all. Can I keep the stock but sell the right to vote on corporate issues to someone else?
Comment: Considering that most (non-institutional) shareholders couldn't care less about their voting rights, the sale value would probably be 0.0001 cent or so.
Answer: I don't know if you can sell them but there is a way to give your voting rights away by designating your proxy to vote as you direct.
For a annual meeting vote, most shareholders don't attend. Instead shareholders are given a mechanism to inform the corporation how they wish to vote on the items scheduled to be voted on. This mechanism was by mail in the past, but now it is more likely to be via the web, or even an app on somebody's phone.
If shares are held by a mutual fund they also vote in these corporate elections; these fund companies or public employees retirement funds can control significant number of votes.
When designating how to vote, the shareholder can direct them to vote yes, no, or to abstain. In some situations the proxy vote just wants to be counted as present for the purposes of achieving a quorum.
Answer: Yes. Sort of.
In theory, you could loan your stocks to a short-seller for a fee. Investopedia says that the voting rights pass to the borrower (presumably until the sale), but if they are never the holder of record, it would be the buyer who then holds voting rights in the usual manner. Regardless, you'll have relinquished voting rights for a fee.

When a security is transferred as part of the lending agreement, all rights are transferred to the borrower. This includes voting rights, the right to dividends and the rights to any other distributions. Often, the borrower sends payments equal to the dividends and other returns back to the lender.
  - Investopedia

Unfortunately, the parties doing the lending tend to be the 'big boys', rather than individual investors:

Securities lending is generally conducted between brokers and/or dealers and not individual investors.
  - Investopedia

I came across something purported to be investor-level stock-lending, but I have no experience with it:

For stock investments too, you can either hold on to your shares and wait for them to appreciate in value or lend your securities through the Security Lending and Borrowing (SLB) scheme to earn money in the interim.
  - Narendra Nathan, ET Bureau

By loaning your stocks, you can enter into an agreement where you continue to receive dividend payments and get your stocks back at some point determined by the agreement, earn some money and forego voting rights. If you package those pieces in a different way, you might consider this to be selling your voting rights while synthetically retaining all the other benefits of owning the shares.
If you're willing to go to the trouble of entering into an agreement, why not simply agree to accept a fee in return for sending the other party as your proxy? The pragmatic answer to that question is that there is an established market for loaning shares to short-sellers, whereas the market for buying proxy votes is, to be polite, considerably smaller - especially when a general meeting of the company isn't looming.
Comment: "When a security is transferred as part of the lending agreement, all rights are transferred to the borrower." Poorly worded article in the link. The borrower does not get the voting rights. He has sold the shares and is short.  The 3rd party who bought the borrowed shares becomes the holder of record and controls the voting rights.
Comment: The right can't be transferred to the borrower because he is never long the equity.  The initial buyer is the holder of record (along with the rights) until the sale to the third party occurs.  This is a minor wording error on the part of Investopedia.  FWIW, don't assume that their word is the financial gospel.  They occasionally print misleading or incorrect information.
Comment: @BobBaerker I assumed it meant that the rights transferred to the borrower *until the sale*. Once sold, the voting rights go with the shares. For the one extending the loan, though, it is an effective mechanism for monetising their voting rights.
Comment: @BobBaerker Thanks, I've edited to address that point.
Answer: If you want the financial benefits of owning the stock without voting rights, there are derivatives that can approximate that. For instance, buy a call option and sell a put option at the same strike price. Or just buy the most ITM call option you can find.
Comment: (1) You might want to note why you're recommending long call + short put. Perhaps to participate in both upside and downside or to defray costs? (2) Long call alone works, but if it is deep ITM, wouldn't this increase exposure on the downside without helping the upside? (3) Dividends, if any, aren't paid to options holders, though they do factor into the pricing of the derivatives.
Answer: You can buy some stocks as preference shares, who haven't the right to vote.  Those stocks often have a slightly different development to the ordinary shares, but not necessary a better one.
But preference shares will give you advantage for dividents, at least in germany. There are some different variant of preference shares, and usually you get a higher divident or guaranteed dividents.
Since i am not sure if i used the right terms in english, i give you example stocks for Volkswagen:
ISIN: DE0007664039 - preference share
ISIN: DE0007664005 - ordinary share
The voting right stays at the company for a preference share, so you basically sell your vote to the company for better dividents.

Is it possible to sell voting rights?


Why is cross product not commutative?

Question: Why, conceptually, is the cross product not commutative? Obviously I could simply take a look at the formula for computing cross product from vector components to prove this, but I'm interested in why it makes logical sense for the resultant vector to be either going in the negative or positive direction depending on the order of the cross operation. I don't have any formal experience in linear algebra, so I would appreciate if an answer would take that into account (I'm merely learning vectors as part of a 3D game math education).
Comment: There are two ways of looking at such a thing: cross product is actually just a binary operation and the formula is, in fact, an axiom. However, axioms are defined so they may be useful and various concepts in physics, such as in electricity and magnetism or in kinetics seem to correspond with this notion.
Answer: The magnitude of the resulting vector is a function of the angle between the vectors you are multiplying. The key issue is that the angle between two vectors is always measured in the same direction (by convention, counterclockwise).
Try holding your left thumb and index finger in an L shape. Measuring counterclockwise, the angle between your thumb and index finger is roughly 90 degrees. If you  measure from your index finger to your thumb (still must be done counterclockwise!) you have roughly a 270 degree angle.

One way to calculate a cross product is to take the determinant of a matrix whose top row contains the component unit vectors, and the next two rows are the scalar components of each vector. Changing the order of multiplication is akin to interchanging the two bottom rows in this matrix. It is a theorem of linear algebra that interchanging rows results in multiplying the determinant by -1.
Answer: Since two vectors are perpendicular to any two non parallel vectors, and these vectors are in opposite directions, it makes sense to decide which one is to be the result of the cross product. So the convention was adopted to follow a right hand triad, as opposed to a left hand triad.
Answer: Because $\vec{a}$, $\vec{b}$ and $\vec{a}\wedge\vec{b}$ are a right hand triple of vectors.
And, if $(\vec{a},\vec{b},\vec{c})$ is a right hand (ordered) triple of vectors, then also $(\vec{b},\vec{a},-\vec{c})$ is, while $(\vec{b},\vec{a},\vec{c})$ is not. Indeed not only cross product is not commutative, further it is anticommutative.
See, also, the cross product tag wiki.
Comment: Yes. Part of the historical development was inspired by electromagnetism where the difference between right- and left-handed systems physically matter. (E.g., the Lorenz force $\vec F$ on an electric charge $q$ with velocity $\vec v$ in a magnetic field $\vec B$ is given by $\vec F = q\vec v \times \vec B$.)

Why is cross product not commutative?


How to access civicrm_subscription_history in Views?

Question: I'd like to extract contacts who have been added to a certain group for a given date or date range. This information is in table civicrm_subscription_history which is included in my Drupal settings file, along with every other CiviCRM table.  But this table doesn't appear in Views - it seems that only a selection of CiviCRM tables appear, and I don't understand why this is. How can I access this table in Views? (I know this is perhaps more of a Views question but hopefully it's also enough of a CiviCRM question!) Using Civi 5.24.5 & Drupal 7.69
Answer: Views CiviCRM Expose Tables might work for you.


Blending for multiple lighting passes

Question: I am attempting to perform shadow mapping with deferred shading, using the following code:
for (auto light : m_ShadowDirs)
{
    //render shadow map
    shadowDirPass(m_ShadowBuffer, light);
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    // activate shader for non shadow casting lights
    m_ShadowDirLightShader.activate();
    m_FrameBuffer.LightingPass(m_ShadowDirLightShader);
    m_ShadowDirLightShader.setUniform(("WSCamPos"), m_ActiveCamera->getPosition());
    m_ShadowDirLightShader.setDirLight(("dirLight"), static_cast<DirLightData&>(light->getLightData()));
    m_ShadowDirLightShader.setUniform(("ShadowTransform"), m_ShadowDirMatrix);
    //bind depth map
    m_ShadowDirLightShader.bindTexture(("shadowMap"),5, m_ShadowBuffer.getDepthTexture());
    //render
    renderQuad();
    glDisable(GL_BLEND);
}

shadowDirPass(m_ShadowBuffer, light); Simply renders the geometry to the shadow map.
m_FrameBuffer.LightingPass(m_ShadowDirLightShader); Just binds the Gbuffer textures.
I have two directional lights in the scene, one with red colour (1,0,0), and one with blue colour (0,0,1)
One would think that the scene would be coloured purple, but no.
Every time I render (for each) light, the image in the target framebuffer is overwritten completely, instead of blended together. To illustrate this, see the following images:

Above is the scene with a single red light.

Above is the same scene, with a single blue light, but from a different direction. (See shadows).
When I enable both lights, the result is as if the first light was never used, though by stepping through the code, I can confirm that it is definitely going through a render cycle.
I'm pretty sure than I've messed up the blending somehow, but I could use some guidance.
Answer: As it turned out, I was calling glClear(COLOR_BUFFER_BIT), between lighting passes, within the FrameBuffer class. Once I removed that call, it worked fine.

Blending for multiple lighting passes