What is a secondary dominant chord?

Question: What is a secondary dominant chord? What's the theory behind them? How are they used in composition?
Comment: V of V of V of V of V is a bit much to follow. I think it's the same thing as V/III. If it doesn't resolve to the III chord, you can call it "deceptive resolution".  So in the key of C, V is G, V/V is D, V/V/V is A, V/V/V/V is E, V/V/V/V/V is B. B7 in the key of C is V/iii. It's easier and more sensible way to analyze it IMO.
Comment: ["Mahna Mahná (duh duh dudúduh)"](https://www.youtube.com/watch?v=8N_tupPBtWQ#t=12) (E7 A7 D)  The E7 here is a secondary dominant chord (dominant of dominant).
Comment: You can have secondary dominants of secondary dominants too.  That is, not just V (dominant) of V, but V of V of V.  Mr. Sandman does this to an extreme: the chord progression (after the bum bum introduction) is: I, V of V of V of V of V, V of V of V of V, V of V of V, V of V, V, I.  It's a little weirder because the Vs are also augmented, but the dominant motion is undeniable.  https://www.youtube.com/watch?v=VNUgsbKisp8
Answer: In common-practice theory, secondary dominant chords are chromatic harmonies used to approach a non-tonic chord with greater urgency. Let's use C major for examples:
I might want to approach the V chord (G) with a secondary dominant to give greater direction or "color" to the approach. I construct the secondary dominant by going to the V chord of the V chord. In other words, I briefly pretend I'm in G Major, and borrow its V, which is a D major chord. The standard Roman numeral notation is V/V, and the chord is chromatic to the original key of C major due to the third (F#). Just as often, I might borrow the V7 from the target chord's key, and this would be labeled V7/V and would be a D dominant 7th chord. Generally only major or minor non-tonic diatonic chords are used as targets, but obviously one could extend this to other qualities and to chromatic chords.
In some cases, particularly V/IV, the secondary dominant would not be chromatic. In C major, the target chord IV would be F Major, and its key's dominant would be C major, which isn't chromatic to the original key. In such cases, composers will almost always use the V7/IV instead, which in C major would have the chromatic note Bb.
The concept is easily extended to vii° chords, since they also have dominant function. In C major vii°/V would be F#dim for example. Most theorists distinguish between the two by calling secondary vii° chords secondary leading tone chords instead of secondary dominants, but the concept is precisely the same.
In all cases, their purpose is to highlight the target chord, and create a sharper resolution to it.
Comment: @JonnyLeeds I'm using the standard meaning: chromatic notes are notes that aren't in the key. It's the opposite of a diatonic note which is a note that is in the key. A chromatic *chord* is any chord that contains at least one chromatic note.
Comment: Really interesting answer, but what do you mean by chromatic/not chromatic here?
Comment: Concise & clear, Thank you! "viio" was the only challenge for me, I guess that means that 'o' is means '0'  or diminished chord?
Comment: @inger Yes, the "o" is a degree symbol which would ideally be a superscript after the "vii" and it means "diminished."
Comment: I see secondary dominants which do not highlight the target chord lots of times, so maybe their purpose is just that, but it doesn't happen. And I believe it doesn't *have* to happen.
Answer: As the other answers have said, a secondary dominant is a 7th chord that resolves to a chord other than the tonic. The classic example is a D7 chord in the key of C: the D7 resolves to G, which itself resolves to C.
Dominants create tension
To understand the theory and practice behind secondary dominants, you have to understand that all dominant chords serve a functional purpose, namely to drive the harmony forward by creating tension.  That tension demands release and resolution, and so dominant chords provide the music with momentum and forward drive.
Sustaining tension is a tricky business. Obviously, music with no tension (and subsequent release) is dull and lacks momentum. But you can't just play the same V chord over and over hoping to draw out the tension as long as possible, because eventually the excitement dissipates and the listener is left with an unsatisfied, unresolved feeling.
So secondary dominants are used to extend the harmonic drive. They create some tension and offer the composer the opportunity to resolve it, but because they resolve to a non-tonic chord, the resolution itself creates new tension that can then be itself resolved later.
Example
Suppose (again) you're in the key of C. You could write a progression that goes something like C-C-G7-G7-C. The first two chords establish a key center (C), the second two chords establish tension relative to that key center, and the final chord resolves that tension.
Now consider this progression: C-C-D7-D7-G7-G7-C. The same basic principle applies: establish a key center, create tension, resolve it—but now the portion of the music that creates tension is twice as long. Playing C-C-G7-G7-G7-G7-C is just as long, but not really effective (try it!), but using the secondary dominant allows the tension to extend without losing its power.
And you can keep this idea going: C-C-A7-A7-D7-D7-G7-G7-C. Now the harmonic tension is three times as long as in the original chord progression, but by using secondary dominants, it manages to sustain interest without dissipating. This is an extremely popular chord progression; in the key of Bb, it goes Bb-Bb-G7-G7-C7-C7-F7-F7-Bb, which you may recognize as the progression behind "I Got Rhythm" and countless other tunes.
And that's the idea. Dominants create tension and make the listener anticipate the coming resolution. Secondary dominants allow the composer to extend that tension, thus raising the emotional stakes of the music.
Answer: Theory
Secondary Dominants are chords that are the Dominant (V) chord of a certain key other than the Tonic (I) key.
For example, let the current key be C Major. An F Major chord is the Subdominant (IV) of the current key (C Major). How about a C Dominant 7th chord? That is not in the current key, but you know it's the Dominant 7th (V7) of F Major, and F Major is in C Major.
That C Dominant 7th chord is therefore the a Secondary Dominant.
Please note that Secondary Dominants can work in all valid forms (including the Root form and its 2 inversions, and the Dominant 7th form and its 3 inversions).
Why "Secondary Dominant"? It's because it's the Dominant of a key other than the original key (as stated in the first sentence). Please note that if a chord that appears to be secondary chord leads to a key change, that chord is NOT considered a secondary chord.
The Secondary Dominant can be the Dominant of any key other than the Tonic. If the current key is C Major (again), then:

The Secondary Dominant of the Supertonic (ii) key, which is d minor, will be A Major
The Secondary Dominant of the Mediant (iii) key, which is e minor, will be B Major
The Secondary Dominant of the Subdominant (IV) key, which is F Major, will be C Major
The Secondary Dominant of the Dominant (V) key, which is G Major, will be D Major
The Secondary Dominant of the Submediant (vi) key, which is a minor, will be E Major
The Secondary Dominant of the Leading Tone key with the root lowered a half step (♭VII), which is B♭ Major, will be F Major.

Remember that Secondary Dominants can also be used in Dominant 7th form. For the 3rd condition (Secondary Dominant of Subdominant), the C Major chord can be C Dominant 7th (and in this case, should be).

How are they used in composition?

Secondary Dominants add harmonic color to the music.
Please note that each Secondary Dominant usually is followed by the Tonic (I) chord of the Secondary Dominant's key. If the Secondary Dominant chord is F Dominant 7th, and the current key is F Major, then the Tonic of the chord is B♭, so the following chord should be a B♭ chord.
Let's do an exercise!
Given that the current key is B Major, and there is an A# Major chord, what chord will most likely follow that A# Major chord?
Well A# Major is clearly not in B Major, and we can see that it's the Dominant key of D# Major and d# minor, and we can see that d# minor is in B Major (the current key), so the d# minor chord will most likely follow that chord.
Notation
Since Secondary Dominants are the Dominant of a certain key, Secondary Dominants are written as V/?, where ? is a Roman Numeral such that the Secondary Dominant is the Dominant of the ? of the original key.
For example, V/V means that the Secondary Dominant is the Dominant of the Dominant of the original key (we'll use C Major again; it's easy to work with). That translates to the Dominant of the Dominant of C Major. The Dominant of C Major is G Major, so V/V translates to the Dominant of G Major, which is D Major.
Let's do another one, where the current key is D Major this time. V/ii of D Major means that the Secondary Dominant is the Dominant of the Supertonic (ii) of D Major, which is the Dominant of e minor, which is B Major. Get it?
In real notation, you don't need to go "V/IV of E Major". Instead, you only need to go "V/IV", because the key is already given in the music score.
Let's do an exercise!
What is the V/VI of a minor?
Well the VI of a minor is F Major, and the Dominant of that is C Major, so the V/VI of a minor is C Major.
Conclusion
That's it! I hope you learned what Secondary Dominants are! Feel free to comment if you have any questions or comments (duh)!
Comment: A good, thorough answer. When writing for example 'a minor' I find 'A minor' easier to read.Could come across as 'any old minor'! Still like II7 rather than V/V7 (or is it V7/V?) to represent say D7 in key C.There's no difference in the meaning, it's less to read, and therefore is better.I've asked this before - lets take A7 in C. That then becomes V/V/V. What's the point ?  VI7 works, doesn't it ?
Comment: For the minor part, it's more proper to write it in lowercase, but good point. For your V/V/V question, think about if A7 will ever appear in C. If it does, it will usually lead to a key change, and then as said in my answer above, it wouldn't be considered a secondary chord anymore (in this case, maybe not "secondary" anymore, but you get the point). Continued...
Comment: For your II7 and VI7 point, please understand that vi7 is A MINOR 7th, not A MAJOR 7th, and ii7 is therefore D minor 7th. For the A7 in C, think about if A7 would work in C. If there was an A7, then it should lead to a key change, and therefore wouldn't be a secondary chord anymore, as stated in the question (maybe not "secondary", but you get the point). If the A7 was put in without a key change, then the A7 would be a vi7#3 (vi7 sharp 3).
Comment: Taking a tune like Sweet Georgia Brown, usually in G, starts with E, then A, then D and back to G (maj. or 7ths). Cycle of 4ths.On the E bit, it hasn't changed key, don't even think it has modulated.I see the E and A as secondary dominants, if in a strange way.   I understand that lower case represents minor, but if one qualifies it with the word, it's not necessary to put lower case.None of the music I've ever played has used that.A bar of C (c) would be too confusing to read - yes, of course, the context may give a clue as to whether it's supposed to be maj. or min., but caps all round .....
Comment: ...with 'm' if necessary is far better to read.        You actually used capitals in the last comment, which to me at least looks better.The vi7#3 is a bit of a contradiction in terms.It can't be a maj. AND a min. That to me hints of the Hendrix chord, which of course, it isn't.
Answer: A secondary dominant chord is when you turn a minor or major 7th chord into a dominant chord, in order to make another chord the tonic chord. I can't tell you exactly what's the theory behind this, but I can tell you a bit about how they're used, not so much for composition but for arrangements:
Take for example a typical chord progression I-VI-II-V. If we use the C scale, then it's CM7-Am7-Dm7-G7
First of all, any degree can turn into a secondary dominant, except the IV.
Now, in this progression, if we take the third chord, D, and imagine for a moment that it's the tonic, then the previous chord, A, happens to be the V grade of D, so we can turn Am7 into A7. This will give the sensation of resolution that happens with the V-I so commonly used in jazz and other genres, but right in the middle of the progression.
But, D also happens to be the V grade of G (if G were the tonic), so we can turn Dm7 into D7 and have yet another feeling of resolution. So we turn the progression into CM7-A7-D7-G7. This is known as extended secondary dominants.
But, that's not all... any dominant can be accompanied by the II degree that precedes it in a full cadence (II-V-I). Using the same example progression (the original one), if we once again turn Am7 into A7 because it's the V degree of D, then the II degree of D would be Em7, so we can squeeze Em7 before A7 and play those 2 chords in the same timeframe in which A7 was played before.
So if you're playing quarter notes, then CM7 for 1/4, then Em7 for 1/8, A7 for 1/8, Dm7 for 1/4 and finally G7 for 1/4. The same can be done when turning Dm7 into D7: squeeze in the II degree of G which happens to be Am7. So now we have:
CM7, Em7+A7, Am7+D7, G7
There are other things you can do with secondary dominants, such as replacing a dominant with the dominant born from its tritone; this means that instead of playing G7, which is G-B-D-F (the tritone is B-F), you can switch the order of B-F to F-B and that would be the tritone of Db7.
Answer:
What is a secondary dominant chord?

There are two parts to the question:

what is a dominant chord?
secondary to what?

In major/minor tonal system the tonic and dominant chords are the two most important chords which define a key.
A tonic chord can be any major or minor triad. The tonic chord is the "home" chord of the key, the principle chord of stability. The tonic chord is usually the first chord of - or prominent at - the beginning of a composition, and it usually is the final chord for the ending.
A dominant chord is a major chord (triad or various types of dominant sevenths) rooted on the dominant degree of a key, a perfect fifth above the tonic.
It's important to emphasize the dominant chord is always fundamentally a major triad. It can be extended with a minor seventh to make a dominant seventh chord, or extended and altered with other intervals, but the basic dominant chord is a major triad a perfect fifth above the tonic.
The third of the dominant chord is always one half step below the tonic degree of the key. That half step below the tonic is the seventh degree of the key and is called the leading tone. So, with a tonic of C the dominant chord is G major. The third of G major is B natural which is the leading tone of the key, one half step below C.
An important concept in the major/minor system is the dominant chord leads to the tonic chord and that progression defines or confirms what key the music is in. That can be regarded as the primary dominant to tonic relationship in any given key. So, with a tonic of C the primary dominant to tonic relationship is a G major chord to C.
The tonic chord can be either major or minor. So, for example, the G major dominant could lead to either a C major triad in the key of C major, or it could lead to a C minor triad in the key of C minor. It's important to understand that regardless of whether the tonic chord is major or minor the dominant chord is always a major chord.
Now that we have defined what are the primary tonic and dominant chords of a key we can look at secondary chords.
In any major or minor key there are always three diatonic major chords and three diatonic minor chords (diatonic meaning chords of the key signature.)
The dominant chord was defined as a major triad a perfect fifth above the tonic, but we could modify that and say a dominant could be a major triad a perfect fifth above any of the major or minor triads of the key. The dominant above the tonic is the primary dominant, but dominants above any of the other major or minor triads in the key are secondary dominants. Again, being dominant chords, secondary dominants are always fundamentally major triads.
So, in the key of C major we have these major and minor triads:

C major, in Roman numerals I the tonic of the key
D minor ii
E minor iii
F major IV
G major V (the primary dominant of the key)
A minor vi

The odd chord out is B diminished, the leading tone triad.
A secondary dominant can be constructed above any of the five non-tonic major or minor triads. Examples: the secondary dominant of E minor is an B major chord, the secondary dominant of A minor is an E major triad.
While the label secondary is applied to these dominants secondary is not applied to the term tonic. There are no secondary tonics. However, the term tonicize is used to describe this special treatment. The secondary dominant B major tonicizes E minor in the key of C major. The secondary dominant E major tonicizes A minor in the key of C major.
In Roman numerals the chords will be labeled like C: V/iii iii or C: V/vi vi where the secondary dominant is indicated with a slash and is read as "five of three" or "five of six."
Secondary dominants are typically chromatic (using tones that don't belong to the key signature.) Notice that those secondary dominant must be spelled with chromatic sharps and flats: B D# F# and E G# B. The secondary dominant triads of IV in major and VI in minor are I and III respectively. Both chords are diatonic to their key signatures. In those cases the secondary dominant identity is a bit ambiguous so a minor seventh could be added to those chords to bring in a chromatic tone for the characteristic chromatic feel of a secondary dominant.
It's worth while to point out that when all the possible secondary dominant of a key are considered (including those secondary dominant seventh chords V7/IV and V7/VI) all twelve tones of the chromatic scale will be used! So, in any major or minor key the whole 12 chromatic tones are immediately related to the key either directly via the key signature or indirectly via secondary dominants (and the special handling of the dominant chord in minor keys.)
Some people misrepresent "classical" style harmony as purely diatonic. That simply is not true. Chromaticism is the norm in classical style. Even the simplest classical pieces often include some chromatic chord, like the secondary dominant V/V.

How are they used in composition?

A very common way to encounter secondary dominants is within the interior of a composition after the initial tonic has been established. (That isn't always the case, but it's common.) From a structural point of view they offer options for building phrases to elaborate and extend the music between the opening and final close.
Being secondary and tonicizations they occur within an established key rather than constituting an complete change of key (which is called a modulation.) The secondary function is brief. Often it's just the two chord progression from secondary dominant to the target, tonicized chord, then the music returns to the established key.
A very common pattern in classical music is for music in a major key to shift emphasis to other tonal regions in a particular order: the dominant, the modal regions of the supertonic and submediant, and then the subdominant. Those shifts can be achieved by modulation or secondary tonicization. This is not an absolute rule, but a common pattern.
Chroma - the root of chromatic - means "color." So the use of these chromatic secondary dominants is often described as colorful.
Answer:
What is a secondary dominant chord?

Let's say we are in C:
V7-I  => G7 = dominant7 of C:  G7 - C
V7/V  => D7 secondary dominant of C:   D7 - G (spelling D-seven is five seven of five of C)
etc. following the circle of 5ths and "running" counter clockwise back to C
Example 1 : V7/V (five seven of five)
C => B7-E7-A7-D7-G7-C = I-V7/V7 (B7-E7)-V7/V7 (E7-A7)-V7/V7 (A7-D7)-V7/V7 (D7-G7) V-I (G7-C)
(spelling one (C=tonic=1st degree) five seven (B7) of five seven (E7) of five seven (A7) of five seven (D7) of five -> one
**Example 2: ii-V7/I: (two minor seven - five seven of one)
ii-V7-I = dm-G7-C
ii-V7/V7 = am-D7-G7 (G7=dominant of C, am = ii of G)
etc.
Example 3: secondary dominants of all degrees:
analog all secondary dominants of some other degrees are:
A7-dm = V7/ii
B7-em = V7/iii
C7-F = V7/IV
D7-G = V7/V
E7-am = V7/vi
F#7-bm = V7/vii

What's the theory behind them? How are they used in composition?

They are used to embellish the harmony. "Primitive" folk music like Swiss music, Yodeling,  children songs often are based (or arranged) only on a simple cadence: I IV-V-I or I-V,V-I etc) (e.g.  Frère Jachues, Sur le pon d'Avignon, London Bridge is falling down, Good night, Ladies)
To embellish the harmony there are short extensions to another tonal center (this can last only one measure!) or we have a repeated phrase  with first ending on the dominant (introduced by a secondary dominant) or a form AABA whith an extension in section B to the dominant (also by a secondary dominant e.g. "Au clair de la lune")
My favorite examples are:
The Preludes by Bach: e.g. C-major, D-major and C#-major (s. my newest question ... link will follow)
You're a Lady (Peter Skellen)
but there are hundreds and thousands more as examples of course!

What is a secondary dominant chord?


Moving an iMovie-11 'work in progress' moving from one system to another

Question: I just discovered that 'system a' has no DvD burner. System B has one. I can drop ilife onto system B, but ... which of the collection of 'import/export' mechanisms makes sense here to use the B drive if the movie is under construction on A? Heck, can I just somewhow share the 'media browser' and just do the DVD part of the process on System B?
Answer: Accessing DVD drives
Under System Preferences > Sharing you can share the DVD drive of B with A.
This should allow you to use the DVD burner on B as though it were a part of A, so you can just keep working on A.
Import / Export
You mention iLife, but not what program in iLife you are using, nor what you are doing with that program, so it is difficult to suggest an export/import method.
Moving 'Work in Progress'
Your question is about accessing a DVD drive, but your title is more generic.
If you want to move work in progress between two computers, you can use a variety of techniques, including, for example, DropBox, USB drives, shared folders over wireless or wired intranet or internet, etc.
Comment: Did you look at the tags:-)
Answer: Do you mean to import/export the iMovie project (or whatever) from system A to system B?
As mankoff points out you can simply share the DVD drive over the network, or alternatively, once you've got iLife on system B, you could browse to your project file over the network (on system B) and burn that way as well.
Using either of these methods you don't need to do any importing or exporting, so they are probably the two best methods for you.
Comment: Oh? It's not working for me. I shared the burner on my macbookpro, and idvd on the mini is oblivious.
Comment: Can you access your Macbook Pro over the network otherwise? Supposing you have file sharing or screen sharing turned on on the MBP, can you see those options fine on the mini?


How can bitcoin be used for all transactions, even with only one confirmation?

Question: If bitcoin is ever going to be mainstream, how can we get around the problem of confirmation time? I don't think I like the idea of having to wait an hour for my transaction to be confirmed so I can leave the gas station after filling up. Even with the usual recommendation of waiting for only one confirmation, that's still 10 minutes. Anything over 10 or 20 seconds becomes a problem if all customers are using bitcoin, because it delays every transaction that long.
Comment: It can't.  Use Ripple.
Comment: One possible solution is called Green Addresses. See https://en.bitcoin.it/wiki/Green_address
Answer: When you pay with bitcoin using a service that uses Coinbase as a payment processor (such as Humble Bundle), it usually accepts in a short amount of time. The reason they can do this is because they check that your transaction has propagated through the whole network and that there are no competing (double spend) transactions.
Once that has happened, the only way to do a double spend is to mine your own block (because everyone else has accepted your first transaction). Mining a block is very expensive so there is very low risk. Certainly less than the risk of credit card chargebacks.
Now if you are selling something very expensive, then waiting for some confirmations would be good. Also in this case the buyer would likely be in less of a hurry.
Comment: That's a good point. Some random person making a small transaction at a retail store or similar is exceedingly unlikely to have access to the computing power to mount a Finney attack and anyone who could would be so rich that using the attack to save $60 wouldn't be worth it. So for small transactions, network monitoring probably is enough.


Developing an image on photo paper, using a scanner?

Question: I've heard that it is possible to take an image on photo paper, either as a contact print or with a pinhole camera, and develop it by using a scanner rather than through the wet process. Does anyone have any experience with this?
Comment: Haven't tried it, but you could probably do cyanotypes using a scanner. Traditional prints cannot be made without the wet process. Even the cyanotype process isn't exactly a dry process...
Comment: You're talking about solargraphy.  Hope you're not in a rush.
Answer: Photo paper is ordinary paper coated with light sensitive chemical. These are crystals consisting of silver combined with iodine, or chlorine, or bromine.  In their natural state they resemble table salt except the crystal are much smaller. When these crystals are exposed to light, the chemical bonds holding the crystal together weakens. Normally we only expose film or paper briefly to light. This feeble exposure weakens the chemical bond which remains and holds the crystal together. Once the film or photo has been exposed in this way, it is necessary to soak the exposed materials in a chemical called a developer. The job of the developer is to seek exposed crystals and completely terminate the bond. This action releases the metallic silver and washes away the other component. The now unbound metallic silver is opaque and thus appears black. This is typically the way we obtain a photographic image.  Lastly, the film or paper is chemically treated to render the image permanent, then washed and dried.
The use of a chemical developer to do this deed can be skipped. If you can figure out how to expose the photo paper to an image using tons of light, the light sensitive silver crystals will self-reduce. Most papers are crystals of silver plus bromine. Now free bromine has a ruddy coloration. When tons of light play on the paper, opaque metallic silver is formed plus free bromine. An image thus forms on the paper. The combined silver and bromine blend to form a maroon coloration.
I don't think it will be possible to use a scanner to cause photo paper to self-reduce. That's OK because you can use readymade sunlight to do this deed. Place objects on photo paper under subdued light conditions. These can be coins, flowers, leaves or tracings on paper or photographic negatives. Best if you overlay with plate glass to keep this all flat. Now take your art work outside into the sunlight. In just a few minutes an image will naturally form. No chemical baths needed. You must admire your solar print hastily because it will soon fade by becoming uniformly maroon. To stop the fading we bath the paper in photographic fixer solution, then wash and dry. Solar printing was a viable way to make prints from negatives for many years in the history of photography.
Answer: If by scanner you mean an image scanner then no. At least not with conventionally exposed photographic paper (if you radically overexpose silver based papers you will get an image of sorts without development, but radically means many orders of magnitude more exposure than normal). Until you develop the paper (or film) there is no image to scan.  In conventional development the silver halide coated photographic printing paper (and film) is converted into visible metallic silver in areas where it has been exposed to light. The developer is always in solution, so always wet.
Answer: A scanner can not work as a substitute to film development, you still need wet process for that.
On the other hand it can work as a substitute to printing and enlarging.
When using this hybrid approach (in B&W at least; color is different) you need only a changing bag, a developing tank, a thermometer and a couple of beakers for chemicals. Your whole "darkroom" could easily fit in a small box or closet.
You do away with the enlarger,  trays and drying racks, which together take a lot of space.
The end results are not quite like wet printed pictures, but for people who are used to the idea that photos should be in electronic format but still want to play the film game it makes good sense.


Is it possible to calculate energy of electron in any orbital and atom in Schrödinger wave model theory?

Question: Is it possible to calculate the energy of electron in any orbital and atom in the Schrödinger wave model theory? If so, how? E.g. energy of the $3s^2$ electron of the $\ce{Na-}$ ion.
Answer: It is surely possible. Note though, that for many-electron systems orbital picture is an approximate description, but that is an approximation on which the whole general chemistry is based on, so that is fine from that perspective. The approximation is known as the Hartree-Fock (HF) model, and thus, to get the energies of electrons occupying some orbitals all you need to do is to solve the Schrödinger equation in this approximation.

As a quick exercise one can do HF calculation in, say, Gaussian, with the following input file:
<code>#P HF/aug-cc-pVTZ Pop=Full

Na-

-1 1
 Na                 0.00000000    0.00000000    0.00000000
</code>
to get this picture of occupied orbitals:

The HOMO with the energy of $-0.01288 \, \mathrm{Hartree} = -0.3505 \, \mathrm{eV}$ is basically the $\mathrm{3s}$ orbital you're looking for (trust me). Note, however, that this energy is approximate since the basis set (aug-cc-pVTZ) is finite. We could do better than that, but that is a different story.

In response to permeakra (since he does not trust his colleagues) I quote an authoritative reference in the field which explicitly talks about individual electrons occupying individual spin-orbitals and orbital energies. As a reference I choose the infamous book entitled "Modern Quantum Chemistry" written by Attila Szabo and Neil S. Ostlund.
Quote #1 (Szabo & Ostlund, p. 50)

This Slater determinant has $N$ electrons occupying $N$ spin orbitals
  $(\chi_i, \chi_j, \dotsc, \chi_k)$ without specifying which electron
  is in which orbital.

Quote #2 (Szabo & Ostlund, p. 54)

$$   f(i) \chi(x_i) = \varepsilon \chi(x_i) \tag{2.52} $$ [...]
The
  solution of the Hartree-Fock eigenvalue problem (2.52) yields a set
  $\{\chi_k\}$ of orthonormal Hartree-Fock spin orbitals with orbital
  energies $\{\varepsilon_k\}$.

Below I also quote what Szabo & Ostlund have to say about Koopmans' theorem, because I already know that won't trust me.

Quote #3 (Szabo & Ostlund, p. 110)
The first theorem [Koopmans' theorem] constitutes an interpretation of
  the Hartree-Fock orbital energies as ionization potentials and
  electron affinities.

See, orbitals with their energies & occupancies do exist in the Hartree-Fock theory. It is the interpretation of orbital energies as ionization potentials which requires an additional theorem.
Comment: It would be great if you'd be a little bit nicer to each other. Every argument can be lead on a non-personal basis. Some readers might interpret this as a hostile argument.
Comment: > The approximation is known as the Hartree-Fock (HF) model  || HF model does NOT give energies of individual electrons, or even orbitals. HF wavefunction is antysimmetrical by electron position exchange, so there is no way to say if some particular electron occupies some orbital, only that 'orbital' is occupied or not. You are probably refering to Koopmans' theorem. It is not about energy of particular electron, but about energy required to build system with a 'hole' relatively to original one.
Comment: @permeakra, no, now I'm pretty sure, you're confused. Speaking of which particular electron occupies a particular orbital is meaningless, but speaking about the energy of an electron at particular orbital is perfectly sensible. Because an electron that occupies some orbital does have a well defined energy, no matter which particular electron it is.
Comment: @permeakra, the fact that electrons are indistinguishable does not forbid us to speak about individual electrons. For instance, in the HF approximation we talk about individual electrons occupying spin-orbitals, and that is perfectly legal (approximate, but legal). What can not be done is some sort of identification that a particular electron (say, twelfth one) occupies a particular orbital (say, $\mathrm{3s}$). But I surely can say that an electron occupies this orbital and that it will have a particular energy.
Comment: >  For instance, in the HF approximation we talk about individual electrons occupying spin-orbitals || Nope, HF approximation has nothing to say about individual electrons or orbital energy, it never appears in the formalism. There is so known 'Koopman's theorem',  which does not hold true and is about ionization potential, most likely it is the energy printed by provided input.  Again, it is not about individual electrons or even electron on the orbital. Read a good QC book.
Comment: @permeakra, which book is a good one? The one which you've read yourself to learn all this non-sense you're talking for already two days? No, thanks. I will better continue my road with reliable & authoritative like the one I quoted in the answer above.
Comment: Apparently you didn't read it, only quoted. A pity.
Comment: @permeakra, I got you. Only you read the right books. And only you understand them the right way. Everyone else is just quoting.
Answer: No. In QM electrons are indistinguishable.
Still, it is possible to associate a somewhat characteristic value, using various spectroscopic methods, i.e virtually 'moving' some electron from one orbital to another (or removing it entirely) and calculating the corresponding energy. This energy, however, is unprecise, as other electrons 'feel' the move of the 'moved' one. Still, something is better than nothing, so people use what they can.
Comment: The "energy of an electron in an orbital" is equivalent to the energy of an orbital" so electron indistinguishability is irrelevant. Orbitals are distinguishable up to symmetry.
Comment: @Wildcat since electrons are indistinguishable, one cannot attribute energy to some particular electron, since any exchange of two electrons gives raise to antisymmetric wavefuction with exactly same energy, that is, from observer's POV indistinguishable from original (and QM does not have internal variables). If you prefer more strict description, QM formalism gives only total energy of the system. It is possible, using some approximations, to give energy to some orbitals, but not individual electrons.
Comment: Besides, systems of many *non-interacting* particles are considered in QM, and for them the many-particle wave function perfectly separates into the product of one-particle wave functions without any approximations. Yes, such systems are rather ideal, but QM in principle doesn't seem to mind that we speak about each and every particle as being in its own one-particle quantum state. There is nothing wrong with that. Of course, for interacting particles such description is approximate, but that's another story.
Comment: How does indistinguishability of electrons cause inability to calculate their energies?
Comment: What you're saying sounds wrong for me. Look, even in the HF approximation, despite what you're saying, electrons *are* indistinguishable. That's why our trial HF wave function is antisymmetric product of spin-orbitals and not a simple product of them. Yes, I obviously couldn't say which particular electron occupies which orbital, but I know what is the energy of an electron is at each and every orbital.
Comment: @Wildcat > What you're saying sounds wrong for me. || Well, you are incorrect. ||| but I know what is the energy of an electron is at each and every orbital  || Nope, you don't.  Neither HF, nor any other method provide a methodology to attribute any energy value to any electron or orbital. Koopman's theorem is about ionization energies (and does not hold true IRL), so it doesn't count, even if people may believe otherwise.
Answer: User permeakra's observation is right, but the inference is not. User Wildcat's answer is spot-on, but missed on one minor point, which I would explain at the end.
This is just a summary of Wildcat's explanation: The idea is that, we have a system comprising of indistinguishable fermions, which is why we need to use the antisymmetrized wavefunction. The LCAO-MO approximation results in a linear combination of AOs resulting in MOs, which can be allowed to occupy, given by electron densities. Variationally, the ground state would lead to the all the lowest levels being occupied, resulting in HF ground state wavefunction. The HOMO, which is $3s$ orbital, would be at a certain energy level which is definitely well defined for a given level of theory.
So, to answer your question, yes, you can calculate the energy of the $3s$ orbital for $\ce{Na^{-}}$. But, what is not possible is to calculate the energy of the $3s^{2}$ electron, because the electrons occupying the $3s$ (or any of the other) energy levels are indistinguishable. Another thing to note is that, when you talk of using a wavefunction to denote electrons, they are highly delocalized, and can occupy more than one energy level at once. Think about the case of Boron atom. Which orbital do you think the $2p$ electron occupies? The $2p_x$ or $2p_y$ or $2p_z$? They are all symmetric in nature, and hence you cannot point at one particular orbital. This turns into a multiconfigurational problem, which is beyond the scope of this discussion. Hence, the implication here is that, the electrons occupying these orbitals would be at specified energy levels, depending on which orbital they occupy.
Comment: No, I disagree. I do *not* miss anything. I know & perfectly understand what you're talking about in your answer and I have never said anything different. I agree that OP used a bit strange language ("the $\mathrm{3s^2}$ electron"), but that his problem and not mine.
Comment: So, I repeat my reasoning her point by point, and then you tell me what I'm missing. 1) We do have *orbitals* in the HF approximation. 2) HF orbitals are *occupied by electrons*. 3) I couldn't specify which particular electron occupies which orbital, but I could tell what is the *energy of an electron on any orbital* is. 4) This energy usually referred to as the *orbital energy* is also know as the *one-electron energy*, which clearly identifies its meaning. 5) Case closed.
Comment: Specifically, for the answer in question, what I say is that I could not tell which particular electron out of total 6 occupies $\mathrm{3s_{\beta}}$ spin-orbital, but I can tell what is the energy of this electron. And since chemistry is ultimately based on the RHF picture, this energy will be the same as the energy of $\mathrm{3s_{\alpha}}$ electron, thus, I simply say "the energy of $\mathrm{3s}$ electron": there are two of them but they have exact same energy in the restricted picture.
Comment: The meaning of the phrase "the energy of $\mathrm{3s_{\alpha}}$ electron" is perfectly well defined: it is the energy of an electron which occupies the $\mathrm{3s_{\alpha}}$ spin-orbital. One more time: I couldn't specify which electron it is, but whichever electrons occupies the $\mathrm{3s_{\alpha}}$ spin-orbital, I surely can tell its energy.
Comment: And another short remark since I notice you talked about "the lowest levels being occupied": conceptually there is no virtual orbitals in the HF approximation. Initially you have as many spin-orbitals and as many HF equations as many electrons there are in your system. In the RHF case where all spatial orbitals are doubly occupied you have as many spatial orbitals and as many RHF equations rewritten in terms of them as many pairs of electrons there are in your system.
Comment: Then in the Roothaan-Hall finite basis set treatment virtual (unoccupied) orbital arise once the number of basis functions is greater that the number of electron pairs. But! 1) These orbitals are just a byproduct of this particular way of solving RHF equations. 2) The quantities related to them do not have the same physical meaning as those attributed to the occupied orbitals. In particular, virtual orbital energies are not the energies an electron being placed here will have, they lack this physical meaning.
Comment: 1. Your answer is absolutely fantastic, no denial, I just wanted to add a point which you missed, and hence I added an answer and not a comment. 2. The question was midway between a genchem question and a quantum chemistry question. It is our duty to clarify the distinction between electron and orbitals. 3. Note the stress on the **2** in the $3s^{2}$ orbital, posted by the OP. I wanted to make sure that the OP understands that except for basic VB theory expressions, $3s^{1}$ and $3s^{2}$ electrons are practically one and the same.


Possible IE7 Background Bug?

Question: I'm encountering something I've never really come across before in IE7.  I have a wrapper div with a background image applied to it.  This image is supposed to repeat all the way until the end of the wrapper div.  In IE7 there seems to be a scrolling issue where if I use the scroll bar to see parts of the page that aren't initially visible, the background image will 'cut off' and not repeat in the last 100px or so. This only happens if I have to scroll to see more content.  It's like it doesn't fully load the background image for areas that aren't immediately visible.
What's strange is that if I use the mouse wheel to scroll up and down the page, the background image repeats just fine and as it should.  If I use the scroll bar though, it will break randomly (never more than 100px but sometimes just the last 20px, 30, 40 etc).
I've tried the following to trouble shoot so far:
1) Added background color to the div as well.  The background color breaks as well so it's not just a background image repeating issue.
2) Added a min-height of 1% to the wrapper div.
3) Added a position: relative to the div.  I read somewhere that this fixes a weird IE7  background bug.  This didn't help.
Thanks for any help.  I'm unsure if there's some hiccup somewhere else in my code that is causing this (which I'll continue to look into) or if it's some well known IE7 issue.  Again I just find it odd that using the scroll wheel on a mouse let's the background render as it should.  Clicking, holding, and using the scroll bar causes it to break.
EDIT: Here is a link to a screenshot of the horrific problem in action.  http://skitch.com/flight/dspeh/ie7bgerror
The top one is with the error.  The bottom screen is how it should load.
Another additional thing I noticed: If I minimize the window while it has the broken background and then maximize it again the background image corrects itself.
Comment: it's quite hard to know what's happen from a screenshot. 'zoom:1;' usually fix most of the disappearing bugs in IE7, give it a try.
Comment: Hmm, a screenshot or live link would be helpful here. Also, try to reproduce it on at least one other machine - this could be a graphics driver problem or something (although it seems unlikely).
Comment: This is quite common in IE6 but less so in IE7, do you have a doctype in your html, if not it could be the page is being displayed in quirks mode.
Comment: hey guys thanks for the help.  I added a link to a screenshot of the problem.  Murdoch: The site does have a XHTML strict doctype.
Comment: Please send a link or examples of your code
Answer: My guess is that the 3 boxes at the bottom are floating div's. Try this:
<code>#backgroundDiv { overflow:hidden; min-height:100%; height:auto!IMPORTANT; height:100%; }</code>
IE6/7 sometimes bug with min-height. This piece of code will cause IE6/7 to default to 100%... IE sometimes likes to use the last declaration instead of following the !important call; whereas every other browser will use the !important call when displaying the page.

Possible IE7 Background Bug?


Private task in sharepoint

Question: In sharepoint Services 3 what is the best way to let people create a private task so that only they and the person that assigned it may see it.
Answer: The best way is with Item Level permissions.  You can restrict access to just specific users.  However this will be a management nightmare.
Answer: I agree that item level premission will be a management nightmare. You'll need to create different lists (for example: a list for each employee).
If there is only one task assigner (one manager for example) or realtively few, than you can create a simple list and configure it to display each user only his on item.
Notice, however, that this way you'll have to make twists, so that new tasks will be created from the employee's user.
And give the manager full control on that list.
Answer: You can setup a workflow that automatically fires on creation; change the permission then.
Answer: I work on SharePoint and am the program manager for permissions management.
I'd discourage you from manually setting item level permissions, as someone posted - this would be a management nightmare, your best bet is either workflow or custom code that sets permissions after an item is updated.
Alternatively, if the creator-assigner relationship is pretty static, then it might be wise to create lists along those lines, that you could then permission accordingly. Note that doing this you'd lose the ability to easily view tasks across multiple creators/assignees.

Private task in sharepoint


What does it mean: to delgate to a baking service?

Question: What does it mean "to delegate to a baking service"? I have my Tezos in my Binance wallet. Is that considered to be delegating to a baking service?
Answer: In layman terms, delegating means you are giving someone else, the baker, the ability to create new blocks using your tokens. Let me be absolutely clear that you are never transferring tokens to a baker. Your tokens are always 100% in your control. Bakers are rewarded for creating new blocks and typically share that reward with those that delegate to them. I suggest you go find a Tezos 101 document as understanding delegating is core/fundamental to Tezos.
Comment: we should also add that delegation also means allowing that baker to vote on your behalf for governance.
Comment: Thank you for the answer, i will read that document. I wonder if you can help me with one more thing: Binance is a Baker? or where can i find it?, thanks again!
Comment: Binance is an exchange that offers staking services to those that keep Tez in their account. They are NOT a public baker. I suggest that you not delegate to "the big exchanges" which creates a centralization of delegations. Use baking-bad.org to find a good baker.
Comment: @MartinPortocarreroMonge please mark the question as answered


Customizing a WordPress theme without changing it?

Question: I have found and downloaded a theme. However I want to tweak the CSS some to change the design, colours etc. a bit. How should I go about doing this, while still being able to update the theme without loosing the changes.
Answer: While you can't modify it without changing it, you can isolate the parts you change by creating a Child Theme. In summary:

Create a theme directory on peer with your "parent" theme,
Create a style.css file in your new directory that has a Template: declaration in the comments naming your parent theme and an @import url(../%parent-theme%/style.css) to import the CSS from the parent theme,
Activate your new theme in the WordPress admin console,
Add new files and/or copy files from your parent theme directory to your child theme directory and modify them to your preference, and
That's it!

I could give you lots more details but basically this guy does a really good job of explaining How to Create a Child Theme so better for me just to point you to it.
When you want to upgrade the parent theme just upgrade; it will leave your child theme in-tact. Of course your child theme may not work perfectly if they've changed the parent too much and/or if you copied and modified theme files they updated in the new version you won't get the new functionality without modifying them too, but it's a lot better from starting over each time!
Hope that helps.
Comment: Child themes are the way to go IMHO
Answer: If all you want to change is a little css, you can create a custom css file inside the theme directory.  Include your custom css file in the theme's header, and write new declarations in the custom css file only, thereby overwriting the theme's default css declarations.
Default stylesheet
body{background:white;width: 960px;margin: 25px auto;}

Custom stylesheet
body{width:800px;}

Your browser will make separate http calls for the two stylesheets and apply styles in the order they are listed.  Whatever declarations are made last will overwrite declarations made before them.  So make sure to include your custom stylesheet after any other stylesheets are included in header.php.
If you are going to end up changing template files like archive.php, or page.php, MikeSchinkel's answer will let you update your theme if a new version is released, without loosing your modifications.  But if all you want is to change some css, This method will work well.  Just make sure that you save your custom stylesheet before updating the theme directory.
Comment: This might be problematic if the theme you modify is not your theme, so your changes might get overwritten on theme updates.
Answer: You can definitely create a child theme. A child theme keeps your main theme in its original format.
What I personally do is, I am using a premium WordPress theme from MyThemeShop. In that, I keep my style.css and theme options file as it is. I just copy the file's data to another file and name it a little different. For example, if I am using SociallyViral Theme, for creating its child theme, I will copy the data from its style.css file and save it to another file naming it childstyle.css.
After this, I will now design specific functions and can redesign my theme by adding more functionalities in the childstyle.css file.
This keeps my original style.css file as it is and enables me to update it in the original format.
Comment: I'm not sure what you mean with "I will copy the data from its style.css file" but usually it is enough to only add those styles to the child theme that are *different* from the parent – the child theme's styles add to and/or override the parent's styles. By the way: how does your answer add anything to the answer that was already **accepted 6+years ago**?!
Answer: If your interested in a good 'Lab Exercise' for trying out the steps described above. There is nice step by step guide for creating a child theme off the default WordPress 3.x delivered theme twentyten. It is a simple but useful child theme (named thirtyten). The result extends twentyten theme from a two column theme to a three column theme. It also has some new header pictures.


Juniper EX-series: How can I transfer a config from one switch to another?

Question: I have a lab EX-2200 that has a config on it that I now want to replicate onto four more EX-2200's... I'm sure there's probably an easy way to do this, but couldn't find it on the Juniper KB or by (a minimum amount of) Googling. Anyone here know?
Comment: I don't know what you're doing with them, but would a [Virtual Chassis](http://www.juniper.net/techpubs/en_US/junos13.1/topics/concept/virtual-chassis-ex4200-components.html) be more appropriate?
Comment: No - these are going to be used for DMZs off a firewall; just trying to quickly put a base config on them. I am pleasantly surprised to see that even with the EX2200 you can do virtual chassis - Juniper rocks :)
Answer: you can copy the configuration from the 'source' switch like this (assuming you've got a domestic software release supporting SSH):
show configuration | save user@otherswitch:myconfig

And then on 'otherswitch' in edit-mode:
load replace myconfig

Comment: That sounds great for config transfers to another switch that's already online, but this case is to configure a new blank switch from another configured switch's setup... Good to know tho!
Answer: You can, of course, also in config mode just:
save somefilename

And then you move that file to the other switch someway, usign ftp, sftp, scp WinSCP, etc., to the other switch, where you
load replace somefilename

Another option is to just view the config in the normal way
show config

and then copy it in your client (clipboard).
Then on the new switch, type
load patch terminal

and paste in the config there. Once done, press  and .
Comment: Be aware that you can run into problems with pastebuffer sizes when pasting large configurations resulting in partially copied configurations.
Answer: I followed the directions in this Juniper document:
http://kb.juniper.net/InfoCenter/index?page=content&id=KB12022
Briefly, I backed up the configured switch's config file to a USB key, and then mounted the USB key on the new switch, and did a load override /mnt/juniper.conf.gz as per the document's "restore" section. Worked like a champ!
Answer: You can use a script to share parts of the config quite easily.
I use the script share-data. You can create your config like this on the switch/router:

groups {
    juniper-distro {
        apply-macro share-data {
            device3;
            device2;
            device1;
        }
        system {
            domain-name mydomain.com;
            domain-search [ mydomain.com anotherdomain.com ];
...........................................
        }
    }
}
apply-groups [ juniper-distro ];
...........................................

You can then use the script to copy the group config to the other devices:

{master:1}
root@device1> op share-data group juniper-distro ?
Possible completions:
              Execute this command
                 Argument name
  database             Database for configuration ('candidate' or 'committed')
  detail               Display detailed output
  target               Target for transfer (one or space-delimited list)
  |                    Pipe through a command

This isn't very helpful for the initial config of the switch as you still need to be able to access it and be able to set the apply-group. The previous posters suggestion of scp the config file over would be my suggestion.
Answer: For four devices applying a default configuration by hand is a good option. However if you'd like to upgrade or downgrade and apply a default configuration to multiple devices then Zero Touch Provisioning (ZTP) might be a more convenient solution for Juniper hardware.
KB27327 has some good information regarding the process as well the Configuring Zero Touch Provisioning article.
Requires;

DHCP server which provides the location of the software image and configuration files on the network
Anonymous FTP, HTTP or TFTP server where the software image and configuration files are stored.
DNS
NTP (optional)
Syslog (optional)
Answer: Let us say that SWA has the config you want to copy and SWB is the new switch. Follow these steps to replicate the configs

user@SWA>show configuration|display set
copy the set commands from this display
user@SWB#load set terminal
Press Enter
Right Click to paste the copied set commands
Press ctrl-D
Commit check
Commit.
Answer: I do not think I saw anyone mention it, another piece of good knowledge to have   are the two commands: commit confirm overwrite and commit confirm merge.
These two commands help with similar things the main difference being that
the commit confirm merge copies content from another configuration that contains data you want to integrate to your current candidate configuration. I generally copy it from notepad++ Or copy it out of the configuration with the copy button in secureCRT. This command does not overwrite any of your current configuration.
Commit confirm overwrite does as it sounds and overwrites the current configuration with the new configuration. A rollback would be necessary to revert from this operation.
Lastly, when committing any new  configuration data, its always good practice to use the commit check command prior to confirming.
Comment: Although this is nice advice, this isn't an answer to the question.


How to derive the period of spring pendulum?

Question: So I wanted to find out how to (simply, if that's possible) derive the formula for a period of spring pendulum: $T=2\pi \sqrt{\frac{m}{k}}$. However, Google doesn't help me here as all I see is the ready-to-bake formula. Could you please point me some directions?
Comment: Related: http://physics.stackexchange.com/q/1018/2451
Answer: You need to know the equation of motion. The force for the pendulum is given by $F= - k x$. Newtons equation tell you $F=ma = m \ddot x$. So you need to solve
$$\tag{1} m \ddot x = - k x.$$
You know that the solution will be of oscillatory form. So you set $x= A \cos(2\pi t/T)$ and you want to obtain $T$. Plugging this ansatz  into the equation (1), you obtain
$$ - m\frac{(2\pi)^2}{T^2} A \cos(2\pi t/T) = - k A \cos(2\pi t/T).  $$
You see that the equation is fulfilled if
$$ m\frac{(2\pi)^2}{T^2} = k.$$
Solving for $T$, you obtain the result.
Comment: @VladimirKalitvianski: thanks for spotting the typo.
Comment: I know this answer was made many year ago, but, in this answer was considered a simplification of cosines. In other words, it is not considering the case cos(wt) =0, is it ? So, this simplification is not correct, is  it?
Answer: There's one more simple method for deriving the time period (an add-up to Fabian's answer). The spring pendulum, as we all know is a great (well-known) example for Simple Harmonic Motion. First, let's assume a particle at any point of the spring. While in an SHM, the acceleration of the particle (at some position on the pendulum) is directly proportional to its displacement ($x$), and is always directed towards the fixed point of the spring. From the past observations, $$a\ \alpha\ x \implies a=-\omega^2x$$
I think you know that $\omega$ is the angular frequency of this particle and the negative sign indicates that the acceleration is opposite to the direction of displacement. If the mass is given by $m$, then the restoring force is given by substituting the above equation in Newton's second law. (For instance, it is $F=ma$)
The restoring force, $$F=-m\omega^2x$$ Here, the $m\omega^2$ is substituted by $k$. Its always a constant for a given spring (and hence the name, spring constant). From this, we could simply get $$\omega=\sqrt\frac{k}{m}$$
Now, time period $T$ is the time taken by the spring to complete one oscillation with a given $\omega$. We could define angular velocity using this time period. A complete revolution per $T$, gives the angular frequency. $$\omega=\frac{2\pi}{T}$$
Equating both, you obtain $$T=2\pi \sqrt{\frac{m}{k}}$$
Answer: It is also possible to dimensionally estimate the period from the equation of motion without solving it, if you roughly replace the second time derivative $\ddot x$ with $L/(T/2)^2$:
$$m\frac{L}{(T/2)^2}=kL,\;\to T\propto 2\sqrt{\frac{m}{k}}.$$ You see, $T/4$ is even better characteristic time estimation for the time derivative.


Does passive smoking break fasting?

Question: If someone smokes close to you and you inhale the smoke involuntarily, does that break your fast? Also, does ruling change between fard fasting and extra (nafilah) fasting?
Answer: To answer the first question, if done on purpose, then yes.  If not intensional, then no.
Depends on your intention according to the following extract from a fatwa:

One's fast is not invalidated by what is too hard to protect oneself
  from swallowing. This includes the dust of the street, the dust of the
  flour, and the like. Although smoking a cigarette breaks the fast of
  the smoker himself, it does not break the fast of a passive smoker
  (the person next to him who breathes in some of the smoke). Also, it
  does not break the fast of one who breathes in the odor of incense or
  other fragrances, however if one deliberately breathes in the
  particles which come out of a spray bottle (whether perfume or the
  like), while remembering that one is fasting, then one's fast is
  terminated.

Full fatwa can be seen here.
Answer: Only if it's intentional.

Firstly, in order for one's fast to become invalid, one has to inhale the smoke intentionally and deliberately. If the smoke of a perfume entered through one's nose or throat unintentionally, then one's fast will not break. (Maraqi al-Falah, P: 660)
  (Source)
Answer: There are studies that show passive smoking is extremely harmful. Taking smoke in directly or indirectly or thru a sheesh all are harmful for the inhaler.
"...make not your own hands contribute to your destruction..." (Qur'an 2:195)
If we know ALL these smoke(passive,active etc) will destroy our lung and still continue to inhale these smoke then we are going against the above verse of the quran. Hence I would deem these smoke as haraam.
I would also include any undesirable smoke like pollution from vehicles in this category.
To explain better I would use the analogy of someone ridiculing Allah's Message...

"Already has He sent you Word in the Book, that when ye hear the signs of Allah held in defiance and ridicule, ye are not to sit with them unless they turn to a different theme: if ye did, ye would be like them. For Allah will collect the hypocrites and those who defy faith - all in Hell.." (Quran 4:140)

In the above verse Allah says that if someone is ridiculing Allah's message, you must go away until they change the subject. This should happen the moment you know that they start to do it.
So if someone is doing something haraam and you must go away if you do not have the ability to stop it.
Now to answer your question about fasts..
If something is haraam on normal days, it is haraam when you fast too (with the exception of food, drink and sex, which is not haraam otherwise)
So if you walk away from the smoker your fast MAY remain intact just like your emaan remains intact, otherwise it MAY have been broken because passive smoking itself is haraam. The reason I use MAY is because here I have used an analogy and not a direct quote or hadees.
But Allah knows best...
Comment: I would be very careful dispensing rulings on this website that do not come directly from qualified scholars. You concluded that taking smoke in indirectly is also haram. Please back that up. Also I would avoid using the word haraam in your conclusion, even with the "maybe" caveat. Just make the analogy and leave it there, or if you have something more solid (like an opinion from a scholar) quote that.
Comment: I have provided evidence from quran as to why smokes(passive, active etc) is haraam
Comment: I would still be happier with a concrete quote form a hadith or scholarly discourse on this though, despite the good logic.
Comment: Muslim scholars deem active smoking as haraam based on certain verses of the Quran (like the one above 2:195). I am simply applying the same verses that cites active smoking as "bad for health" to passive smoking .
Comment: This doesn't answer the question if passive smoking breaks the fasting. The only thing you have added is that passive smoking is generally haram, which first of all goes against the majority view and secondly isn't related to the question at all! Also just because one does something haram when fasting, doesn't mean one breaks the fast per se. Therefore -1.

Does passive smoking break fasting?


Buying bulk hops online

Question: I'm often tempted to buy my commonly used hop pellets online in bulk and storing them in my freezer.  A lot of the cheap bulk hops are from the previous year.  Assuming they are vacuum packed and frozen, is it safe to buy 2008 harvest hops or am I wasting my money?
Answer: It's safe if stored properly. Their bittering power will diminish with time - software like ProMash will help you estimate their current alpha acid content.
Before using them just take a whiff to tell if they have developed any cheesy aromas. You can always make a giant batch of lambic if they get too old.
Comment: Are there sources online you would recommend that can be guaranteed to have stored the hops properly to begin with?
Comment: I have only used http://www.hopsdirect.com/ About to make another order.
Answer: As long as you factor in the loss of alpha acid over time you should be fine.  A reputable supplier may even help you with the estimate.
I would also recommend that you plan to use them relatively quickly if you want to get the most out of them.  So think of your next 3-4 brew sessions and work with those hops.  I'd invest in a vacuum sealer yourself, to weigh and repackage these hops you get.

Buying bulk hops online


Math Outdoor/Camping Games and Activities

Question: Me and my 7th-grade students are going to a 3-day trip. It's an excellent opportunity to have some outdoor math games and activities. What games and activities do you suggest? Do you know any source for finding them?
Comment: There was a similar question asked on [Math.SE](http://math.stackexchange.com/q/144698/26306).
Comment: Here is a link to a Norwegian magazine for teachers with a thematic issue about outdoor mathematics: http://www.caspar.no/tangenten/2007/t-2007-2.pdf
Answer: Students can play many estimation games. Students can find objects in nature and then challenge others to estimate the length, weight, and surface area.  These can be checked with measuring tools and whoever is closest gets a point.  Determining who is closest is also a mathematical exercise.
You can also make a list of things to find (a scavenger hunt) with a range of lengths or weights, e.g. between 5 and 6 inches or between 25 and 30 grams. Give them a time limit to find the items.
One of my students favorite games which can be played when walking in a group is where I pick a number (e.g. 3,050,322, 3/7,  -25, or 0.55673) and the students have to guess.  I give them no clues to start but they are told higher or lower.  Give the class a time limit to find the number.  Start with reasonable numbers e.g. a whole number in the thousands and work your way to harder numbers.  Always write the number down on a paper in your pocket so they know it's really the number you picked.  If they guess the number in the time limit they get a point and if not you do.  For some reason they adore this game.
Hope these ideas help.
Comment: What does the 'guess the number' game teach them?
Comment: It forces them to translate between spoken numbers in word form and numbers in standard form including decimals.  It teaches them to order numbers including fractions, decimals, and negative numbers.  If they are trying to guess the number in a time limit, they soon realize that the number in the middle of the range is the best guess and therefore they have to perform the mental math of calculating the middle of the range between the lower and higher bounds. It also forces them to listen to the previous guesses so that their guesses aren't worthless.
Answer: On one outdoors activity day, we got set a version of the little child's toy with three posts and different size rings made out of numbered tyres. I would consider the reasoning in that a form of maths.
(When the instructor realised I knew how to do it, he insisted we started again without me saying what to do. So I pointed.)
Comment: What is "the little child's toy"?
Comment: The one like this: http://www.matematikciler.org/images/Hanoi-Kulesi.jpg
Comment: @JessicaB You mean the [tower of Hanoi](https://en.wikipedia.org/wiki/Tower_of_Hanoi)


Absent the original golden plates, which translation of the Book of Mormon is considered to be the "official" version?

Question: I'm curious what version of the book of Mormon is considered the official version? For example, when translating the book of Mormon into other languages, what is used as the "base text"? Presumably if we had access to the original golden plates the translators would use those, but seeing as they are lost, some other version has to be regarded as "the most authentic". Which is it?
Comment: I recall hearing that there's a special text called the "translator's edition," that's basically a reworking of the English edition with annotations to clarify ambiguities, specifically for use in translating the Book of Mormon into other languages, but I'm having a hard time finding sources that speak about it.  I'll do a bit more research before posting an answer.
Answer: The latest edition of the Book of Mormon can be considered the official version. When translating the Book of Mormon into another language:

The two or three people who are selected as translators team up with others in doing the work. They have Church headquarters supervisors, local reviewers, a lexicon for reference,6 translation guides, computer programs, and ecclesiastical support that extends all the way to the First Presidency. ... This doesn't mean that a translation is perfect when first completed. Often, time and further reviews by those studying the scriptures suggest improvements in grammar and vocabulary or find typesetting or spelling mistakes. Rarely, changes are made in the explication of doctrine. When these are made, they are made under the guidance of the First Presidency.

See the articles Scripture Translation into the Language of the Heart or Every Man in His Own Language for further details on the translation process.
6 The lexicon defines every word in the English scriptures so translators can better understand the meaning of the words. Often, words have more than one meaning, so translators must depend on context, inspiration, and teamwork to identify the right solution. Occasionally, questions about meaning are resolved only by the First Presidency.
Answer: depperm is right, the latest edition of the Book of Mormon (published by the LDS Church) is the official version. However, other versions exist and are sold in the 'official' LDS bookstore (Deseret Book).
Royal Skousen, a professor at Brigham Young University, has been working for over 20 years on a project to recover the original, or earliest, text of the Book of Mormon. In other words, the text that Joseph spoke as he translated from the golden plates. The culmination of that work can be found here. Also, this link is a nice explanation of how Skousen's version differs from the current 'official' LDS version.
Comment: Welcome to Christianity.SE. For a quick overview, please take the [Site Tour](http://christianity.stackexchange.com/tour). Thanks for offering an answer here, complete with supporting links. For more on what this site is all about, see: [How we are different than other sites](http://meta.christianity.stackexchange.com/q/1808/20394).


How to show data of user that flagged a content(2 flag types)?

Question: I have 2 flag types for a content type. both flags have flag field. consider the user flagged a content by both flags. I want to show user data. I have problems in this situation. I add flag A and flag B in relationship part of views, after that I add "username of user" and "flag field" in fields part. but unfortunately I should add 2 "username" field, one of them should relation to flag A and other should relation to flag B(relation part in field setting). this is problem. because I want one field of "username", not 2 "username" fields.
What should I do?
Answer: Add a filter for the whole view that checks username in both fields as not null,  and set the operator to 'And'.
In your view under 'Filter Criteria' do the following:

Add user name with the first relationship and set the operator to 'is not empty (NULL).
Do the same for the second username field.
Click the dropdown arrow next to add for 'Filter Criteria'. Select And/OR, Rearrange and add an 'AND' operator between the two filter.
Hide the second username from display.

That way you can filter for users with both flags.
Comment: Could you explain more? because it didn't work, maybe I didn't understand good
Comment: I added more points under my initial answer.
Comment: @Hamed : the "hide" (item 4) is actually the views option "Exclude from results". Maybe that's the part you didn't understand?
Comment: Thank you Balmong, work great.
Dear Balmong and Dear Pierre I asked new question about this problem here. http://drupal.stackexchange.com/questions/214185/
Answer: It seems that the crucial part of your (updated) question (as in revision 3 of it) is that you need use filters that are related to "either of your 5 flags", which means that Views should use an "OR" (instead of "AND", which is the default) in its query.
To make that possible, you can use the Views Contextual Filters OR module (which only has a dev version today, though close to 2K sites are using it).
Excerpt from its project page:

... provides a views plugin which modify query to support OR conditions for contextual filters.
... A new option will appear in settings page query. If the option is enabled the query will be rewritten using operator OR.

Have a look at the image below (also from the project page), near the bottom of it there is a checkbox titled "Contextual filters OR":

So after you enable this module and check this checkbox, you may get it to work. To actually do so, you need to enhance/correct the view you already seem to have, similar to what is detailed already in the answer from balmong. But for the filter criteria make sure to use "OR" (instead of "AND"), and make sure you do so for all your 5 flags (as in your updated question, so not just for the 2 you originally mentioned).
Comment: See my updated answer. If that still doesn't help (or is not sufficient), then please update your question by adding a screenprint of how the view you already have looks like (using the views UI).
Comment: I should use OR in "Contextual Filters" !? I enabled it now, what should i do after that?
Comment: Dear Pierre I asked new question about this problem here. http://drupal.stackexchange.com/questions/214185/
Comment: Looks like you performed the equivalent of a rollback from revision 3 to your original question. Since my answer related to revision 3 of it, the best I can think of is to add a link to that revision in my answer also ...


What is the difference between different Canon Speedlight transmitter ST-E3 model names?

Question: Is there any difference between the ST-E3-NR and the ST-E3-RT transmitters? Or are they both the same?
Answer: Probably not as far as functionality goes. The only place I can even find a reference to the ST-E3-NR is on web pages based in Germany. Since these are devices that use radio frequency transmissions to communicate with the same compatible flash (the Canon 600EX-RT), the regulations in Germany concerning devices using certain frequencies may be different and necessitate a slightly different version to comply with those requirements. Even the photo for the ST-E3-NR at amazon.de is of the ST-E3-RT.


Chinese-Chinese dictionary definitions re-using characters from the word

Question: I see Chinese-Chinese definitions which re-use the characters of the word.  For example, 领导 defined as 动:带领并引导大家开展工作. If I already knew 带领 and 引导 then I probably could guess 领导, so it's not very helpful.  In English, the "rule" is that you never use the word in the definition. Are there any rules or features of Chinese-Chinese dictionaries that can help me in situations like these? Should I be looking up the individual characters?
Comment: This circular referencing is actually something that has plagued Chinese dictionaries *for millenia*. Welcome to the world of Chinese!!
Comment: Look up 'in' in an English dictionary. See if it is defined without using a word containing 'in'. Look up 'big'. See if it is defined without using a word which means 'big'. The cause of your ire is not a Chinese monopoly!
Answer: 带(lead) + 领(lead) = 带领: to lead
引(guide) + 导(guide) = 引导: " to guide"
领(lead)+ 导(guide) = 领导: "to lead and guide"
领导 contains the meanings of both  带领 and 引导, I don't see anything wrong with the definition using 带领 and 引导. Yes, both 带领 and 引导 repeated one character from 领导, but they are unique compound words on their own.
It is ok. as long as the dictionary doesn't use the exact compound word in the definition like 领导(v): 领导
It is unavoidable for many different compound words to have a common character among them, you have to look at the whole compound word instead of looking at the two characters individually
The examples below all contain '正' (correct, positive, straight, upright....) but each compound word containing '正' would have very different meaning to each others

正直 = honest
正確 = correct
正常 = normal

One more thing:

领导(动):带领并引导大家开展工作

The definition should just be: "带领并引导" (to lead and guide)
领导大家开展工作 would be a good example sentence
Comment: Tang Ho, I think you mean guide, not guild.
Comment: opp, used the noun instead


How can I drag windows over the panel?

Question: Basically, I want my windows to go wherever on the screen. I don't want to panel to be a block. How can I disable not being able to drag windows on top of not under the panel? Oh, and, yes: gnome-panel.
Answer: Have you considered autohiding the panel and the setting a show delay so that it doesn't pop up AS SOON as you touch the top?
For the autohide just right click and check autohide from the panel properties menu. For the show delay hit ALT+f2 and type gconf-editor. Click EDIT > FIND and check both boxes. Search for "show_delay" and select the first result. Change the value to anything higher than 100. (I use 700, personally)
Answer: You can install the compiz settings manager, go to "window rules"under "window management" and write gnome-panel on the field labeled "bellow" (Note: I'm writing this in a computer with Portuguese localization and trying to translate the terms to English so some names may be slightly different).
Comment: Did this work for you? When I type gnome-panel into that box, nothing changes, even after a 'killall gnome-panel'. Using (type=dock) doesn't work, either...
Answer: In compiz-config, go to window rules and add type=Gnome-panel (case is important!) in the "Below" field.
Please note that alt+f2 will now be below as well, so add <code>(title=Run Application) & (type=Dialog)</code> to above.
Please note this DOES NOT WORK in Metacity

How can I drag windows over the panel?


How to create a new instance of Sql Server 2005

Question: I forgot my password for Sql Server 2005. Windows Authentication is not enabled so I cannot login. How can I remove the current instance and create a new db instance? Or is there a better solution exists?
Answer: Assuming you are a member of the Windows Admininstrator group, you can put the server in Single User mode, you could try this -
http://blogs.msdn.com/raulga/archive/2007/07/12/disaster-recovery-what-to-do-when-the-sa-account-password-is-lost-in-sql-server-2005.aspx
Answer: My read of the question was that the server is set up to use SQL authentication only, and perhaps you don't know the sa password or any other SQL login credentials? If so, you might be able to change the authentication mode. For SQL Server 2005 default instances, it's stored in the registry at:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.1\MSSQLServer
in a DWORD called LoginMode. A value of 2 indicates Mixed Mode (both Windows and SQL authentication are supported); I think 0 is Windows only and 1 is SQL only. You can try changing it to 2, restart the MSSQL service, then try to get into the SQL management studio after logging into the machine as an administrator.
If that fails, you can create another instance by re-running the setup program.
Answer: Have you tried connecting when logged on as domain/server-local Administrator?


How do I keep my bed sheets organized?

Question: I have several sets of bed sheets, and I would like to keep the like patterns together, ideally in a way that does not make my linen closet a total mess. How can I go about doing that?
Answer: I know this may come across a somewhat trivial response... But have you tried folding them up before putting them away?
I like to make sort of towers with my sheets in order to keep them all together - so have the duvet cover on the bottom as it is the biggest, then the bed sheet, followed by the pillow cases.
An issue might be that the bed sheet is the hardest to fold if it is a fitted one so below is an image of how you can fold it up neatly to go in with your piles.

If you keep them all folded and organised in the cupboard then you shouldn't have a problem with them causing a mess. You could always find a couple of old boxes to pop them in or a carrier bag or something similar to avoid them inadvertently falling apart from each other.
Comment: So, using the flat sheet as a storage container for the other parts? That's also pretty nice! Probably a bit nicer than using the pillowcase, even. I'll have to try that approach and maybe even switch to it.
Answer: I use one of each sheet sets' pillow cases as a container for the other parts of each set.  Fold the flat and fitted sheet in the normal way, and place them into the pillow case. If there is a second pillow case, fold it up and put it into the storage case as well.  In that way, your sheet set stays organized and fits onto whatever storage shelf you use in a neat little bundle.
Comment: @MrPhooky It seemed kind of obvious... It's the storage in the pillow case that amazes people when they see it, not the specific way in which I folded things. :) But I added a little more detail.
Comment: This is a good answer, but please add a little bit more information to the answer as it is a little short doesn't contain any information regarding how you put them in the pillow cases etc...

How do I keep my bed sheets organized?


Does Jiren simply use brute force?

Question: Hit is a powerful opponent for Goku because he can use time skip and manipulate time and space.
Could this be said for Jiren, or is he simply an overpowered character?
I'm NOT comparing the two, I'm simply providing an example.
Comment: From what I've seen Jiren is just crazy strong. Most of the villains in the DBZ universe kind of of follow a niche (Freeza had multiple forms, Cell had all the cells of the world's strongest, Buu was a demon of unimaginable power). Jiren is just broken it doesn't seem like he uses any sort of real powers or abilities yet. As the tournament progresses, I'm sure something will come out
Comment: He hasnt showed any special abilities other than predicting object and person movements
Answer: Jiren is not overpowered.
tl;dr More Power (KI) ≠ Stronger Fighter

The point of the character is to illustrate the difference of strength between powerful mortals, gods of destruction, angels and others we probably haven't seen yet. Jiren could be at a level between god of destruction and angel. The fact that he seems overpowered means we still have a long way to go until Goku reaches a level where he is considered the strongest.
In DBZ and even GT, Goku seems to be near to the level of all of his opponents before finally surpassing them. Super is taking a different approach. Goku and the others are struggling to even perceive the strength of their opponents. Other techniques and skills throw a monkey wrench in the idea of "more power = stronger fighter". Time skip, ultra instinct, and the energy of destruction are all examples of technique trumping raw power.
The new anime is changing power scaling and what it means to be a powerful fighter. DBZ and GT relied on transformations to show a character was at a higher level. Super, like the original Dragon Ball, is pivoting to strategy and use of different techniques to show a fighter's skills are advancing.
Answer: Jiren is just overpowered that's all. But Goku (or even Vegeta) with ultra instinct can maybe win against him somehow... Its hard to believe that this beast can be beaten but yes... it is possible.
Comment: Just pure speculation here, but maybe he won't be beaten. It is also possible that Goku's universe simply wins due to remaining number of people still in the ring. So technically Jiren won't be defeated in terms of fighting. But for the tournament itself his universe will most likely lose. Goku might be able to take him head one until time runs out. By default the universe with the most people still standing in the ring will then win. In the arc with Zamasu we were shown that in dbs... some villians remain undefeated, unless it is for Zen-oh.
Answer:  Let me make something clear, Hit isn't a character strong for his power(If compared to the power of these high tiers and godly tier characters). What makes him strong are his dangerous assassin techniques which allow him to manipulate time and space
Even during the first fight between Goku and Hit during the Universe 6 vs Universe 7 arc, we need to realize that both of Goku's very powerful attacks didn't actually touch Hit. Hit's timeskip allowed him to dodge both the attacks which is why he managed to survive.Even during the rematch between Goku and Hit, we see Goku capable of tanking multiple blows from Hit and even surviving a shot which almost killed him. However, one powerful Kamehameha in his improvised SSJB form, was capable of taking out Hit (a double K.O), during the match. Even during the match between Hit and Dyspo, we see Dyspo's punches actually hurting hit a lot at the start. We see Goku on the other hand taking 2 back to back punches from Dyspo like it was nothing.  If I were to distinguish the current strongest characters(mortals), I'd put them on the God Tier and the High Tier Scale :
God Tier
Jiren: He is the strongest mortal in the anime at the moment and his power is said to rival that of a Hakaishin. He obviously possesses a lot of techniques and experience like Goku but ultimately, what makes him unbelievable strong is just his brute strength and power. We do know that technique can sometimes counter power. (We see hit being able to do this with goku), However,  Jiren's power rivals that of Beerus (at 100%). So his power is off the scale and even Hit's best technique wasn't sufficient enough to subdue him. UI Goku: This transformation is Goku utilising a skill which the Gods strive to master. At the same time, it certainly does act as a power multiplier which makes him very strong and he's definitely not in his base form or his attacks wouldn't even touch Kefla or Jiren. One's he manages to attack perfectly in this state, and match Jiren's power, it would bring him closer to the power of the gods High TierGoku SSJB + Kaioken*20 Kefla SSJ2 ToppoVegeta SSJB = Golden FreizaHit In terms of power, Hit is a lot weaker than the rest of the high tier characters. He is certainly very powerful, but even a mid tier character like 17, gohan or dyspo (Fighting at full power) might be able to give Hit some trouble if they manage to counter his special abilities which they very likely wouldn't be able to because of Hit's superior experience and complex level of skill. Also, you need to realize that Goku wouldn't struggle with Hit's time skip anymore in his UI state. Unlike Goku who needed some time to adjust to time skip, Jiren was able to completely dodge all of Hits attacks and even counter most of the time initially simply because of his amazing reaction time. The UI transformation makes Goku's reaction time perfect, so technically, Goku would be able to dodge hit's time skip and overpower him.
Answer: Overpowered is the correct description for Jiren. So far what was shown was pure raw power from Jiren. We weren't introduced to any special ability yet (in the anime, I don't know how it is in the manga).
It was rumored that a mortal was living in an universe with power that exceeds the god of destruction. I don't know the exact episode but Whis and Beerus were talking about it when Jiren showed his raw power for the first time.
If Jiren has any special/unique abilities it will still have to be presented. Which will make him significantly stronger or weaker if an ability might be the reason for his insane raw power.
Just the way saiyans and different species are able to power up through different forms Jiren might be possessing a similar treat.
Based on what we have been shown yet Jiren is simple overpowered. The punch of his fist alone causes enough force to destroy surrounding areas. None of the other characters in the tournament so far are able to have a similar force in their base form.
Comment: To be fair, not all characters require transformations to get stronger. That's an exclusive Saiyan trait. Fighters such as Jiren, Toppo, even the gods like Beerus, Champa(at least, since we've seen them fight), don't use any transformations. So there's no actual reason for Jiren having one. I'd say it's more of him suppressing his energy and utilizing the sufficient amount to overpower his opponent. Just like Beerus did when he fought, SSJ3 Goku and the Z fighters.
Comment: Thats true, but that means that they have a fixed raw power, the can lower their output, but the limit remains the same. A different form (for example) can increase this limit. Thats why I called it a "similar treat" since not all methods of powering up goes through transformations. But it is too early to conclude what Jiren's abilities/limits are in terms of powering up and such.

Does Jiren simply use brute force?


How are API changes announced?

Question: How are API changes announced? Are emails sent out to developers, or is there someplace I can subscribe to?
Answer: They're not announced via a dedicated channel, perhaps because there haven't been too much changes in years. Version 2.2 has been the latest stable release and while there is a newer 2.3 version to support the official mobile apps, it hasn't been released and probably never will be since the apps are deprecated.
We regularly discuss the API on Meta Stack Exchange as an often-forgotten part when new changes are being rolled out (e.g. the new close reasons or the renaming of favorites to bookmarks) but those are relatively minor changes (sometimes the format doesn't even change). And there's no good way to monitor those changes either.
A year later, 2.3 has been released and the company chose an announcement on Meta Stack Exchange as medium.

How are API changes announced?


Weight on front or back of feet

Question: When discussing correct posture for standing still, you often hear people talk about standing on both feet and not placing all your weight on either one of them. However, beside positioning your weight left-to-right, you can also position it front-to-back. I noticed I naturally place most (say 75%) of my weight on the front of my feet. What do experts say about this?
Comment: Are you asking which of these is correct posture, or better for you?
Comment: I don't know about which is better posture but when I had a job where I had to stand up for 12 hours a day, 6 days a week, the back of my feet (my heel bones) hurt a lot (even though I was wearing very comfortable running shoes). I was putting my weight on my heel bones the whole day. I had to consciously start putting my weight towards the front of my feet (ball of foot) for some periods so that I wouldn't get too much pain on the back of my feet.
Comment: @HDE 226868, correct posture in general: "better for everyone", if that exists.
Comment: @Jorge Luque, that makes sense. I can imagine too much in either direction is not good. Considering the heel of your foot is somewhat pointy, whereas the front is flatter, perhaps it's better to lean forward slightly. I'm just wondering if there are any reputable sources about this.
Answer: So there are a few things making this a difficult question to answer.  Much of the in-depth research hasn't been done on healthy individuals (biomechanics of the foot), but where there's something wrong (pathomechanics of the foot).  There is also a difference between what is theoretically best (found here) and what people actually do (sort of found here).  Also, the search terms might not be readily apparent because the biomechanical word for "standing" is "stance" (eg "load distribution in stance").
The best models and papers I found were also behind pay walls (which my institution has access to), but I can summarize the information as follows:
There are 6 main points of pressure in the healthy foot: the heel, and the head of each (5) metatarsals:

The metatarsal head of the hallux (big toe, labeled 2 above) should take about 2x the pressure as the other 4 heads, which roughly balances the left to right load on the foot.
As far as front to back, the only reference I found that calculated an ideal position was the one I mentioned before, and seemed to indicate the heel should receive 52.6% +/- 1.36% of the load of the foot (Fig 7).  Presumably the rest of the weight would then be distributed to the metatarsal heads as mentioned above.
I will say that was calculated with math I don't quite understand, and on a very idealized adult foot.  It might be much more useful to ask the question: "How do people with healthy feet and gates distribute the load on their feet?"
That would go back to my second reference and give us this lovely figure: [Fig 1]

My final conclusion is that if you are concerned about your gate you should see an OT or PT. Check for uneven wear on the feet, and try to stay "balanced."

Weight on front or back of feet


Raspberry pi custom SD card image

Question: I have a project uses Qt GUI which works on raspberry-pi2; however I don't want users to interact with the operating system. I just want that the only application appears on the screen (from boot to shutdown) to be is my application. Actually the retropie project has done what I actually want. So I want to prepare an minimal SD Card image like that. Is there any tool or way to do that?
Answer: Here're a few pointers.

Hide boot messages and use fbi to show custom logo / images or mplayer / omxplayer to show some animation while Rpi boots to mask background utility
(Here is a link : How to add custom loading screen?)
Boot to x and use openbox by modifying <code>/etc/xdg/lxsession/LXDE-pi/autostart</code> file.

Comment first 3 lines and add following two.
<code>@openbox
@/path/to/qt-programme-binary
</code>

Make sure your qt program is full screen.

Important notes :

Do not keep your qt program source in Pi as your SD card could be physically available to others as you ship it with your product and they can plug it in to a linux box and extract your code / binary.
If you're so concerned about security and others using your binary / setup, you should consider device lock down on the basis of Rpi mac address or serial number embedding into your program and somewhere in start up so that it boots only with your device and hence copying your sd card image won't work on other Rpi devices.

Hope it helps.
Comment: better option 1, if it's a QT with QML app not need run X for work ... (use more memory to run X before QT)

Raspberry pi custom SD card image


Tags for specific software versions

Question: What's the policy on tags for specific versions of a piece of software? For example, the php tag has the most use, but php4 and php5 are also being used, and there's even php5.3. Should any of these be synonymed or deleted?
Answer: We kind of go back and forth on it, but version numbers do matter in some cases. This does lead to things being tagged multiply when they don't need to be. Witness all the questions tagged:
tomcat tomcat5.5
It matters, as I imagine it matters somewhat for things like php.
It's one of those battles where the nuance of where to use a version number and where the Community doesn't think they're needed is hard to express.
Where it falls down is minor point-revs. THAT we don't need.
Comment: So [tag:php5.3] should be killed, but not [tag:php4] and [tag:php5]?
Comment: I'm not a PHP person so can't tell if there is enough different between 5.3 and 5.4 to merit different tags. Generally we don't need it, but there are exceptions.
Comment: It's worth noting that, especially in the case of PHP, that minor points can at times be critical.
Answer: There are questions which are very much version dependent and there are questions which apply to all versions. It follows therefore that the tags you referenced should all exist. This is no different to operating system tags. e.g. I may use the generic windows tag on one questions and a version specific one elsewhere, depending entirely on context.

Tags for specific software versions


A word expresses destiny that ties people together

Question: In Chinese, there is a word called "yuán fèn", which means the destiny that ties people together, at special time and place. In English, is there one word that can express that meaning?
Comment: I found this Wikipedia page: http://en.wikipedia.org/wiki/Yuanfen. I don't know an English word that fits this meaning perfectly. (I know a few words/phrases for it in my first language.) In English, I would probably use either *destiny* or *fate*.
Answer: The closest equivalent English* word would appear to be fate:

fate  (fāt)
n.

The supposed force, principle, or power that predetermines events: Fate did not favor his career. - thefreedictionary.com

Fate can be used in the context of individuals (his fate, her fate etc.), groups (their fate, they were fated etc.) or as an overarching power (fate was against them) in a way that is not quite as applicable to the near synonym destiny. Which as the first definition at thefreedictionary.com implies is usually used in association with individuals:

des·ti·ny  (dĕs′tə-nē)
n. pl. des·ti·nies
The inevitable or necessary fate to which a particular person or thing is destined; one's lot.

*A loanword that also seems to be a close match is kismet.
Answer: There's no one word, but the English phrase we're all in the same boat seems to convey the same meaning.
Answer: The answer to the question is "no!". There are many cases of words in one language that have no exact equivalent in another language. This makes the life of a professional translator difficult. It is also why to speak a second language well you have to understand it internally without reference and translation into your first language.