Can someone solve this sudoku without trial and error?

Question:
I'm stuck on this sudoku. If anyone can solve this, then please share and explain the method that you used.
Answer: A simple hint:

 In column 6, you've correctly identified that rows 2 and 8 can only be 2 and 9. That means row 1 can't be a 9; row 3 can't be a 2; and row 7 can't be a 2 either.

This technique is called a naked pair; it seems you've used it already in row 7 to eliminate the 9's in row 4 and 6.
Answer: As Glorfindel has found, you can

 eliminate the 9 in R1C6 and the 2's in R3C6 and R7C6

Then, there's a chain:

 If R5C4 = 9, then R5C9 = 8, R7C9 = 9, R7C8 = 8, R1C8 = 9, R1C5 = 7, R6C5 = 2, R4C5 = 9, R5C4 is not 9.
 This is a contradiction, so you can eliminate the 9 from R5C4.

Then another chain:

 If R6C4 = 7, then R6C5 = 2, R4C5 = 9, R1C5 = 7, R1C6 = 8, R3C6 = 5, R3C4 = 2, R7C4 = 7, R6C4 is not 7.
 This is a contradiction, so you can eliminate the 7 from R6C4.

The rest is trivial.
Not an easy puzzle. I could not find easier techniques to use.
Comment: This is not too long, but it is still trial and error to me.  "If ... (trial) then .... then contradiction (error)".
Comment: @FlorianF If it can be done without trial and error, I'd like to know. I couldn't find any easier ways to solve this one.
Comment: @Dennis_E When it comes to identifying chains with contradictions, is there a pattern or technique involved in doing so? For example, how did you know to start with R5C4 and R6C4. I get stuck on puzzles like this all the time.
Comment: @AnitaTaylor I'm not an expert, so I don't know what the best way is. But I look at chains of cells that contain pairs, like the 89, 89, 89, 89, 79, 72, 29. R5C4 is connected to both the start and the end of that chain, so I try one of those numbers. (Yes, I suppose this is trial and error but all the basic techniques I know were exhausted)
Comment: Agree with @FlorianF. Logically the phrase "without trial and error" does not make sense.
Answer: We can solve this puzzle with two sudoko techniques.
First with Naked Pair (already @Glorfindel discussed). This one will fit with column $6^{th}$, where $2$ and $9$ will follow the naked pair, and remaining $2$ and $9$ from column $6^{th}$ would be eliminated.

second with XY-Wing, where R6C5, R7C3 and R7C6 fit for the XY-wing technique. We will choose $7$ from R6C5, and this number will fit (other number $2$ from R6C5 will not fit here). Please see the below in the picture.

Final solution looks like.
Comment: I don't see how that hidden triple works. There should be a 4 pencilmark at R5C4 but it somehow went missing from the hidden triple picture.
Comment: @JaapScherphuis I have corrected my printing mistake. $2$, $3$, and $4$ of R5C2, R5C7 and R5C8 will follow the hidden triple technique. That why 2, 3 and 4 will be in either R5C2 or R5C7 or R5C8. Therefore we will remove 4 from R5C4, 8 and 9 from R5C7.
Comment: But how can it be a hidden triple if the 4 pencilmark occurs more than 3 times in that row? If that was allowed you might as well say the 8 and 9 form a hidden pair in that row.
Comment: @JaapScherphuis I think, it is naked triple. Am I right?
Comment: I don't think that row is anything. There are only 5 open cells. A naked triple would correspond to a hidden pair on the other unused digits in the row, and a hidden triple would correspond to a naked pair on the other unused digits. A priori it is perfectly possible for R5C4=4, as that leaves two naked pairs 2&3 in R5C2+R5C8 and 7&9 in R5C7+R5C9. Nothing in that row rules that out, although the rest of the grid may well make that impossible.
Comment: Through this [link](https://www.learn-sudoku.com/naked-triplets.html), might be naked triple will fit.
Comment: For that you would need 3 cells with only 234 (or a subset), but here one has 23489. Note that a hidden tuplet allows you to remove canidates only from the tuplets own cells, and a naked tuplet allows you to remove candidates only from the other cells in the house. You cannot somehow mix the two to remove candidates from both sets.
Comment: @JaapScherphuis I have updated my solution with correct method.
Comment: According to your link, an XY-wing needs one cell to "intersect" the other two. How does R6C5 intersect with either R7C3 or R7C6?
Answer: It can be solved with elementary techniques. Using my solver (CSP-Rules, available here: https://github.com/denis-berthier/CSP-Rules-V2.1):
naked-pairs-in-a-column: c6{r2 r8}{n2 n9} ==> r7c6 ≠ 2, r3c6 ≠ 2, r1c6 ≠ 9
biv-chain[2]: r2n9{c7 c6} - c5n9{r1 r4} ==> r4c7 ≠ 9
whip[1]: b6n9{r5c9 .} ==> r5c4 ≠ 9`
biv-chain-rc[4]: r3c4{n5 n2} - r7c4{n2 n7} - r7c6{n7 n4} - r9c6{n4 n5} ==> r3c6 ≠ 5, r9c4 ≠ 5
singles to the end


1000 pound to invest

Question: Apologies if this question is of incredible "noobish" nature, but this is something that's been bugging me of recent.  So, suppose I have a thousand laying in front of me, what are my targets for investment? Unfortunately, I know very little of shares, and presume that investing in low-share price companies following a company disaster/startups that are anticipated to attain strong market share -- all of which could x-fold my inputs.  Alternatively, and something else I know very little of, are premium bonds.  But my question is, how could I maximize the potential of an investment, small or large (I don't mind risk associated with understanding the nature of the company).  Any help would be greatly appreciated!
Comment: Generally the higher the risk the higher the return. If you want to 'maximise' potential return and if you 'don't mind risk' then try betting it all on number 0 of a roulette wheel. I'd call that 'a gamble' though, which you're likely to lose: not 'an investment'.
Answer: ChrisW's comment may appear flippant, but it illustrates (albeit too briefly) an important fact - there are aspects of investing that begin to look exactly like gambling. In fact, there are expressions which overlap - Game Theory, often used to describe investing behavior, Monte Carlo Simulation, a way of convincing ourselves we can produce a set of possible outcomes for future returns, etc.
You should first invest time. 100 hours reading is a good start. 1000 pounds, Euros, or dollars is a small sum to invest in individual stocks. A round lot is considered 100 shares, so you'd either need to find a stock trading less than 10 pounds, or buy fewer shares. There are a number of reasons a new investor should be steered toward index funds, in the States, ETFs (exchange traded funds) reflect the value of an entire index of stocks. If you feel compelled to get into the market this is the way to go, whether a market near you of a foreign fund, US, or other.
Answer: Depending what your timeframe preferences are, here are a couple of options:

Stock indexes: as per Fool's investing guide, historically this had the highest return / risk ratio. On a 5-year horizont, with no extra work, this seems the best option.
Premium bonds, similar to most cash ISAs currently available, have a rather rubbish ROI ATM (~3-5% AER at max)
Invest it into yourself, in the form of personal development, classes & courses, or starting a business. Disadvantage: this also will carry an opportunity cost in the form of your time. On a longer timeline, however, if this improves your market value only by 1%, that pays extreme dividends over the rest of your carrier.

With a single grand at hand, I'd definitely recommend going for option 3 -considering yourself as an investing vehicle, and ask yourself: how can you best improve stakeholder value?  You'd be surprised at the kind of results a single grand can make.
Answer: 1000 (£/$/€) is also not a lot to start with.  Assuming you want to buy stocks or ETFs you will be paying fees on both ends.  Even with online brokerages you are looking at 7.95 (£/$/€) a trade.  That of course translates to a min of .795% x 2 = 1.59% increase in value you would need just to break even already.
There is a way around some of this as a lot of the brokerages do not charge fees for their ETFs or their affiliated ones.
However, I would try to hold out till at least $5000 before investing in assets such as stocks.  In the meantime there are many great books out there to "invest in knowledge".

1000 pound to invest


How should I translate this sentence? "I saw that he killed your friend."

Question:
I saw that he killed your friend.

I am puzzled before I translate it when considering the expression of verb tense. I will give two translations

私は彼があなたの友達を殺したのを見た

私は彼があなたの友達を殺すのを見た

Which one is correct and why?
Answer: The latter is better, though the former is not wrong.
As you know, verb tense is relative in Japanese. Regarding your sentence, it seems that the incident was ongoing at the relatively present time when 'I' saw him. So we typically use the present tense in the noun phrase; namely, 殺す rather than 殺した.
But the former translation is not wrong. In this case, 殺した sounds like 殺してしまった, that is, 'have killed.' So it implies the speaker saw he finished killing the friend.
If you want to emphasize the concurrency, the following translation is fine:

私は彼があなたの友達を殺すところを見た。 (I saw him killing your friend.)


Google Sheets Labels are returned as empty strings by SQL. Why?

Question: I have a Google sheet for testing on which I want to run a query via a http: request using JQuery $.ajax. Works fine until I paste some additional rows. Still works then but when I remove any of the rows above the pasted ones the query returns "" for labels instead of the first row of the sheet. This means SQL is not recognising the first row as a header row which means sort by includes the first row. I have other sheets where everything works fine. It just seems pasting fouls things up.
The reason for testing like that is that if I do a straightforward paste of say a list into an empty sheet and do the query, labels are always returned as "". Any data entered manually gives the expected result of labels=first row.
Any ideas?
Answer: After a lot of hunting around as the Google docs is far from complete it looks as though the first row of a sheet can be forced to be a header and its cells used as labels by appending &headers=1 or indeed &headers= x if there are several header rows to the https query string.
I haven't tested this exhaustively but it seems to deal with a couple of bad use cases OK.
What I haven't figured yet is why things worked OK in other sheets without &headers.
Comment: Without a parameter to specify headers, the query guesses at how many header rows (0,1,2...) there are, based on the content. Sometimes it guesses incorrectly, and it's hard to say why.


Is there any way to prevent endless "best first printer" posts?

Question: It's pretty manageable right now due to the low question rate, but I think maybe ~3% of all questions this site will get, forever, will be "what's the best printer" or "what printer should I buy" type questions. They're mostly coming from people who don't know enough about 3DP to articulate their requirements, so they're difficult to help and very unfocused. Is there a better way to handle this than locking them as they come up?
Comment: It seems the best solution is to create an intro to 3-D printing that answers this question and can be easily discovered or promoted to new users, perhaps somewhere along the right hand side?
Answer: A good option would be to have several reference questions, such as "What to look for when comparing printers?" or "How to select a 3D printer?" to which we could redirect these users.
Comment: It might be a good idea to initially specify the type of machine (FDM, SLS, DLP, etc) in the question to try and avoid "too broad" issues.
Comment: I think this sounds like a good idea to start with. Since there still are not that many posts on this site altogether, manually posting links to a set of proper answers for "standard questions" will not be too much effort. A good reference question might also make reach far up on search engines, and therefore reduce the need for new users to ask those same questions over again as well.
Answer: I think the site tries to prevent this as best as possible, short of having a bot prevent the post.

There is the Don't Ask page and the On-Topic (which we have control over its content).
The suggested/related questions that appear when asking a question. Ideally users at least regard its existence before posting the question.
There appears to be a pop-up that does try to warn the user that their question is "subjective". I tested it really quick, see the image below
All else fails, that's what moderators are for. Moderators should utilize the tools available to them. So even if these types of questions pile up, there are means of quickly identifying. A simple feature, available to everyone, is advanced searches. I try to use searches like this to quickly identify large groups of questions that may need attention.

It might be nice to have more options over whether keywords can be contained or not, "asker" reputation, "answerer" reputation, etc.
Comment: Eek, that pop up is interesting. It's not always effective, and I wouldn't rely on it. As for searches, the [Data Explorer](http://data.stackexchange.com) may come in handy. Your second point kind of raises the classic "chicken and egg" problem. If there isn't much that addresses the user's problem, it doesn't help.
Comment: @Zizouz212 That link is amazing! There's so many little tools tucked away, it gets hard to keep track of what's available sometimes.
Answer: You've got a few options:
1.
Often, what we do is you have a canonical "catch-all" question.
Since the shopping questions seem to have been deemed off-topic, this is probably your best bet. What you need to do is to guide users to select a printer themselves, but by asking them a set of criteria. Therefore, you would need an answer that addresses the following questions (but in no way limited to the following):

What filament do I choose?
What's my budget?
What size do I need?

... etc.
With such a post, you guide users to what they want, and then in the end, you can recommend a few printers.
Also, this question has to be locked using what's known as a wiki-lock. This way, the community can edit the question to update it, and it prevents spam and other nonsensical answers.
2.
You close them as off-topic.
Since this seems to be a persistent problem, it would be helpful to add a custom close reason (hey mods! That's for you!). Something along the lines of this would be good:

Questions asking for the recommendation of a printer or other 3D printing-related resource are off-topic because they tend to attract opinion-based questions, low-quality answers, and spam. For more information, see [Why are recommendations off-topic and where can I ask?](link to a meta post)

You get the community to get support for the close reason, and a moderator implements it to allow questions to be closed. Bingo!
However, you're going to need a meta post explaining why they are off-topic as well as other information. That's good etiquette: you don't leave users stranded and you continue to guide them to where they can ask a question.
3.
You do 1. first.
Then, you allow such "shopping" questions to be on-topic, as long as they follow the specific criteria and answer all the questions that you have outlined in the meta post. Otherwise, you close it.
Numerous sites do this. On Open Source, we allow questions that ask for the recommendation of an open source license. We have a meta post on what you need to include, as well as a dedicated close reason in case something is not of quality. It works very well.
The only downside, is that it can take a bit of time and work to get right.
Answer: I face this question very very frequently. On 3d printing and 3d printing hobbyists facebook group we can see this daily.
The ideas of giving people a catch all set of questions is nice.. That is exactly what I did 6 months ago. I put it in the group rules and did everything I could to get people to read it. To date 0 people, even after directly being told to, have used my list of questions.
In my opinion we need to educate the user, nicely. Also we need to remove the question with flagging. Hopefully without offending the person and thus scaring them away from the community.. Maybe just flag as duplicate, etc. Unfortunately this will one of those situations where we cannot perfectly solve.


Ground Cover Identification

Question: What type of ground cover is this?  Is it a weed?  Very low growing in patches on my lawn.
Answer: We call it "creeping charlie" and it is a very invasive, pernicious weed. The botanical name is Glechoma hederacea.Creeping Charlie 1. It spreads very quickly and easily, it has small purple flowers. Leaf shape may vary some but that is Creeping Charlie, here's another picture of it in bloom.1]1
Comment: Wow!  Its a weed.  But I actually like it!  Any harm to grow it as a ground cover in between stepping stones?  Or do you recommend something else?  Thank you!
Comment: There is no "harm" in growing it in between stepping stones, the problem is confining it to where you want.
Answer: It looks nothing like the creeping charlie in my lawn - wrong color and growth habit. It may be the very small, invasive Geranium lucidum. If so, the flowers will be pink: https://www.kingcounty.gov/services/environment/animals-and-plants/noxious-weeds/weed-identification/shiny-geranium.aspx.

Ground Cover Identification


Why did Jordan kill herself?

Question: In Terminator: The Sarah Connor Chronicles S1E3: "The Turk", John and Cameron are entering a new school. When they came to the school they saw some kind of drawing on the school wall and they also see this kind of drawing a few times in the school. There was a girl named Jordan in the school upset about it and in the end she commits suicide. John tries to save Jordan, but Cameron wouldn't let him. What is the meaning of the drawing on the school wall and why did Jordan kill herself?
Answer: Jordan is the girl in the third image, with blonde hair.
The images suggest that Jordan did something inappropriate with someone (probably a teacher) and that someone else knows, and they are slowly revealing it. Jordan is afraid that people, particularly her parents, will find out the truth. As they reveal more about the door scene, they are also revealing the name Jordan.

Why did Jordan kill herself?


calculating investment principal after monthly withdrawals

Question: I am trying to find a formula for calculating the annual or quarterly principle remaining in a compounded interest investment account with no additional investments but with monthly withdrawals.  Basically, what will I have in my invested retirement accounts each year while I am withdrawing money on a monthly basis.  I am looking for the formula, not looking for an online calculator.   Thanks.
Comment: Consider, a mortgage adds interest monthly, and a payment reduces the balance owed. The math is identical to what you're trying to do.
Comment: Of course if either returns or amount withdrawn varies from month to month, you need to decide whether to use an approximate expected average for those numbers or compute it one month at a time, which calls for a program or spreadsheet rather than a simple compounding formula.
Comment: I created a spreadsheet that annualizes monthly expenses then calculates yearly balance and cost of living increases over 35 years and provides for variable withdrawals and variable rates of return (by blocks of years) and then plots out annual cost of living and account balance over the 35 years. Without the formula for future value, I was calculating investment gain at the beginning of each year and at the end of each year, after deducting cost of living, and using the average of the two. As compared with using the proper formula, the old method was under reporting the balance, so...thanks!
Answer: To calculate the balance (not just principal) remaining, type into your favorite spreadsheet program:
=FV(Rate,Periods,Withdrawal,PV)

Rate = type in the MONTHLY interest rate (so, if you expect to get 6% per year,
type in 6%/12 or 0.5%)
Periods = type in the number of MONTHS elapsed since the initial investment
Withdrawal = type in as a POSITIVE number the monthly withdrawal amount
PV = type in as a NEGATIVE number the (present) value of the initial investment

It is important that the periods for "Periods" and "Rate" match up.  If you use your annual rate with quarterly periods, you will get a horribly wrong answer.
So, if you invest $1000 today, expect 6% interest per year (0.5% interest per month), withdraw $10 at the end of each month, and want to know what your investment balance will be 2 years (24 months) from now, you would type:
=FV(0.5%,24,10,-1000)

And you would get a result of $872.84.
Or, to compute it manually, use the formula found here by poster uart:

This is often taught in high-school here as a application of geomentric series.
The derivation goes like this.
Using the notation :
r = 1 + interest_rate_per_term_as_decimal
p = present value
a = payment per term
eot1 denotes the FV at end of term 1 etc.
eot1: rp + a
  eot2: r(rp + a) + a = r^2p + ra + a
  eot3: r(r^2p + ra + a) + a = r^3p + r^2a + ra + a ...
  eotn: r^np + (r^(n-1) + r^(n-2) + ... 1)a = p r^n + a (r^n - 1)/(r-1)
That is,
FV = p r^n + a (r^n - 1)/(r-1).
  This is precisely what exel [sic] computes for the case of payments made at the end of each term (payment type = 0). It's easy enough to repeat the calculations as above for the case of payments made at the beginning of each term.

This won't work for changing interest rates or changing withdrawal amounts.  For something like that, it would be better for you (if you don't want online calculators) to set up a table in a spreadsheet so you can adjust different periods manually.
Comment: +1 yes, `1000 * 1.005^24 - 10 (1.005^24 - 1)/0.005 = 872.82`
Comment: That is the formula I was looking for.  I did find the Excel Fv function, which makes life easy, but I did want to know how it calculating the result.
Comment: @LarryC, please mark my answer as correct if it answers your question.  Thanks!
Answer: Given the following variables
s = initial balance
r = periodic interest rate
w = periodic withdrawal (at period end)
b[n] = the balance in period n

Where b[n + 1] = b[n] (1 + r) - w and b[0] = s
then b[n] = ((1 + r)^n (r s - w) + w)/r
For example, illustrating with some figures.
s = £1000
r = 0.02 = 2% per quarter
w = £100 per quarter

The balances in the first four quarters (n = 1, 2, 3, 4) are
b[1] = £920.00
b[2] = £838.40
b[3] = £755.17
b[4] = £670.27

Check
As per the Excel formula provided by OneTruDragonGirl
=FV(0.02, 4, 100, -1000)

£670.27


Stop raspberry pi from turning on when plugged in

Question: I am planning to use raspberry pi in an embedded design. Is there any way i can prevent the pi from automatically turning on when plugged in?
Comment: Add a mosfet/relay/power-transistor to the power input.
Answer: If you have a Rev 2 Raspberry Pi you should have a P6 header, which is intended for a reset switch.
I would imagine if you held the board in reset from before powering up (the pins shorted) it should prevent it from booting up until you release it from reset (disconnect the pins).
This will require a small amount of electronics, I assume this is not a problem if it is for an embedded application.
eLinux - P6 header
Comment: Can anyone confirm this, don't want to damage my pi.
Comment: Good idea - just the implications... Nearly everywhere I look gives the indication that only momentarily shorting the pins are a good idea - Have you tried this yourself @PiBorg?
Comment: I have not, usually with other devices this is connecting a reset line (with a weak pull-up) to ground, which will prevent the chips starting. In the event the chip has started this reset line going low triggers an internal reset which would then wait of the line to go high again (remove the short) before starting.
Answer: keeping that pin shorted is a bad idea for the Pi and the power supply(it puts a load on it causing heat).
you need to build a software switch for power on if your intent is to use it with other devices that would turn it on (done by a relay to control power to the main port) or hard wire a actual switch for the power.


1020 on Windows 10

Question: As we know 1020 gets up-to 38mp in default camera app. But what about 1020 with windows 10 ? Does the default windows camera app on 10 support 38mp? Or does any other 3rd party app supports that kind of quality!
I badly need to know this because am planning to go for it only because of its 41mp camera. If windows 10 doesn't support it, then it will be a waste to buy it.
Answer: So far it doesn't look like the L1020 will get W10. At least mine hasn't received an update, yet. So I wouldn't base your decision on that. So far I wouldn't even upgrade if W10 was available, as Microsoft has proven, that some features do get a lot worse on a new Version. (e.g. Onedrive in W10 is a joke compared to W8.1)
Especially Nokia Drive will not be supported on W10, so if you want to enjoy the camera, do it with W8. And try out the camera before buying it, as it's a lot slower than newer Lumia models, who use PureView on fewer pixels.
Answer: It still Rocks! Lumia 1020- for what it is made for.
In my experience atleast, Nokia Camera app (aka Lumia Camera) works equally great for me in Windows 10 Mobile as it used to in Widows Phone 8.x. I always use RAW output for my final work mostly. (It only struggles w/ RED highlights)
I've learnt photography through this camera in my early amateur days. And I still love doing with it. Only thing you need w/ it is patience though!

Additional Information:
I've recently recovered my (bricked) Lumia 1020. And upgraded it to Windows 10 Mobile 15254.527 (w/ Aug 2018 update). I've been using this phone since 2014 and also active as an Insider. From my experience now, all I can say is:

Its working so much better than Preview builds of W10. I'm currently on Windows 10 Mobile 1709. It is quite stable and all of those much needed apps are working good.

(Fluent design elements are working in apps like Groove Music, Store, etc.)
Currently working apps in my device:

Lumia Camera (aka Nokia Pro Cam / Nokia Camera),
All the "Angry Birds" ;)
Camera 360 Sight
CamScanner
Flipkart
Groove Music (it is quite good actually)
Hyperlapse Mobile
Instagram
Lumia Panorama (& other Lumia apps)
News
Opera Mini(but it sucks),
Paytm,
Saavn,
SHARE.it,
SBI app,
Telegram,
Whatsapp,
VLC

And I would like to say that FB, Messenger & few other apps were also working and they've got improved UI, but I'm not using them currently.

I am using it for photography and telephony (of-course), a few games, loads of songs, sometimes chat and internet.
Working Tweaks
(thanks to XDA, etcetra) I've got fully functional LED Notification. (Windows button in Nav bar), Glance Screen with background image, Brightness slider (instead of Low/Med/High its Darkest settings really helps in the night), Lockscreen timeout to: Never (helps in preventing Lumia's hotspot disconnection) and a few other minor tweaks working.

Also, I found the following bummer(s) in the latest W10M:

Truecaller and UC Browser are not longer available.
Amazon app, Olacabs are crashing
'Here' ecosystem (Here Maps, Here Drive, etc.) only works upto build 10586.xxx & Windows Maps are not working properly.
I used Maps a lot back in WP8.1, but in W10M they are kinda non-sense. Only Satellite view is usable. Aerial view is unable to render streets from up-close. (I'm currently working on this problem. Because I found out that GPU in my Lumia is not being used when I use Maps...Help needed!)
Instagram sometimes crashes and lags, but it works decently and that's okay for me, atleast.
Remember: WP8.1 only provides Instagram beta :(
Project my screen app is not working for me, I guess because I've USB 3.0 ports on my PC and it is said to have problems with that.
I've only encountered 3 unexpected restarts in around 20 days.

PS: I still need to check the performance & heating of device for Hyperlapse Mobile and Long video's for time-lapses.
Answer: Yes, it supports that. Windows 10 is the successor of Windows 8(.1), so it'll same or better according to Microsoft. It would be weird if the next version of  an operating system would become worse than before. You don't have to worry about the mp. Microsoft is working hard to Keep improving it. I hope that will help you.
Answer: Lumia 1020 is not in the supported list of phone that are eligible for Windows 10 upgrade. You can see the list of eligible phones here. So it is best to stay in Windows phone 8.1.
Regarding your question the Lumia Camera app worked better on Lumia 1020 during the Insider preview in Windows 10. Windows 10 default camera app had some problems with Lumia 1020's camera.

1020 on Windows 10


Requesting recommendation for an application to detect sound card and its capability

Question: Is there an application that can detect the kind of sound card the computer has and list its capabilities like playing 24-bit sound or playing 192khz audio?
Answer: PassMark SoundCheck is a Windows based application that allows users to test their PC sound card, speakers and microphone. Verify that your sound card can record and playback sounds at various audio sample rates.   Check the capability of your speakers to reproduce the highest and lowest frequencies (and your capability to hear these frequencies).
Some Other Features
1-  8, 16 and 24bit recording and playback.
2-  Adjustable frame rate for slower PCs.
3-  Source device selection when multiple sound devices are installed
http://www.passmark.com/products/soundcheck.htm


Up/Down Quark Color and Isospin

Question: I'm reading some notes that say the reason that the strong interaction conserve isospin is because the up and down quarks have the same color... but I'm not very convinced. Is this a universal truth? Or does it just apply to e.g. baryons? Or is it that on average, there will be equal amounts of ups and downs with red, green and blue? Or is my understanding of color wrong altogether...?
Comment: Yes, up-quarks and down-quarks have the same color charges: they are what is called 'triplets of color' - each quark comes in 3 colors -. And when one says, e.g., the iso-spin of the up-quark is 1/2, it applies to all its colors.
Comment: I get that, but doesn't that just say that "up and down quarks can have one of the three same colors", rather than "they have the same color"? Or am I just being too pedantic?
Comment: I deleted my answer as it became obvious I was a bit sleepy and couldn't devote enough time to ensure quality. The colour flow through the vertex handled by QCD rules as and @xi45 mentions will sort your isospin conservation as if coupled to the strong force there can not be a change in flavour.
Answer: The strong interaction works with colored gluons. The up and down quarks have the same type of color couplings--nothing about their color couplings can recognize whether they are up or down, they are R, G, or B, colorwise.
So you would expect the strong interactions to be indifferent to their flavor difference, up to their "slightly" differing masses (*). (They of course have different charges, so electromagnetic and weak interactions break strong isospin.)
So, yes, isospin symmetry is a "universal approximate truth" --- an "almost conserved quantum number in the strong interactions. The same type of symmetry, except less good (more approximate) holds for the strange quark, the celebrated origin of the SU(3) flavor symmetry of the strong interactions, which bind all hadrons together: baryons and mesons.
Now for the subtlety (*): The isospin symmetry would be perfect for the masses of the u and d quarks being equal, but they are evidently not: in fact, one of them is twice as heavy as the other!
$$
m_d\sim 4.3–5.2 MeV, \qquad
m_u \sim 1.8–2.8 MeV.
$$
However, because both of these masses are much smaller than $v_{QCD}\sim 250 MeV$, the characteristic (condensation) energy scale of the strong interaction vacuum related to chiral symmetry breaking, they are comparably negligible w.r.t. that scale in this process: gluons can largely effectively regard either type of quark as massless.
As a consequence, they fetch up as almost degenerate constituent quarks,
$$
M_d\sim 340 MeV, \qquad M_u\sim  336,
$$
precisely because the nonperturbative QCD interactions largely ignored their small mass differences--and charge.
These are the additive building blocks of hadrons.
When you look at the isomultiplets in hadronic physics, 4MeV is the rough difference between the d and the u quark, so then, small potatoes. (A further factor affecting the symmetry of wavefunctions in baryon spectroscopy is also distinguishability, but this is not part of your question.)

Up/Down Quark Color and Isospin


Minimal Pairs Highlighting the Difference between American and British English

Question: Does anyone have a list of minimal pairs, highlighting the difference between American and British English?
Thanks.
Comment: American English _caddy_ sounds like RP _carry_.
Answer: The problem is that "minimal pair" refers to two distinct words in one language signified by the choice of one vs. another sound. So minimal pairs  are not what you want. You want a list of "same word" pair between the dialects. The Oxford English Dictionary is pretty much the definitive work on English (you may need to access the online version, which gives US and UK norms)
Answer: The Wikipedia page on lexical sets has various tables comparing the vowels phonemes that correspond to each multi-dialectal diaphoneme. The first table compares General American to RP; I think that is the one you will find most useful.
Two caveats: the tables don't include consonants (although there have much less dialectal variation than vowels in English), and they also list lexical sets that correspond to the same phoneme in different dialects (you'll have to filter these out to meet your requirement of "highlighting the difference").
Answer: Since transcriptions of GA usually write short vowels, where I wouldn't, I put length markers in parentheses.
Merry, marry, Mary
/mɛɹi : mæɹi : mɛːɹi/ RP(English standard)
/mɛɹi/ GA(American)
stork, stalk
/stɔːk/ RP
/stɔɹk : stɔ(ː)k ~ stɑ(ː)k/ GA (~ Cot-Caught merger)
father, bother
/fɑːðə(ɹ) : bɒðə(ɹ)/ RP (not a minimal pair)
/fɑ(ː)ðəɹ : bɑ(ː)ðəɹ/ GA
Cot, caught
/kɒt : kɔːt/ RP
/kɑ(ː)t : kɔ(ː)t ~ kɑ(ː)t/ GA (~ Cot-Caught merger)
writer, rider are a minimal pair in some Canadian and Northern American accents but I think the differing vowels might not be phonemes (yet).
This list could be continued, but minimal pairs are not always the very best way to compare the varieties.


Two accounts from the same IP for different people?

Question: My sister and I would like to have separate accounts. But I see that StackExchange allows only one account per IP address. In that case, how do we do it? We really don't want to ask questions from the same account.
Answer:
But I see that StackExchange only allows one account per IP address.

This isn't true; both of you are welcome to create your own accounts
However, please do not vote on each other's posts, as otherwise we might find vote abuse to have taken place.
Comment: You mean people run socks from the same IP?  What in the world are they thinking?
Comment: @Alenanno, sometimes we might not even know about each other.  For example, my employer has more than 10,000 people in diverse locations all hitting one web proxy, so to the outside world we're all the same IP address.  If we had more users on the same SE sites we wouldn't necessarily even know who each other are.  (I don't think we have too many on EL&U, but I'll bet we do on SO and others.)
Comment: Ah, that's not at all a problem. Great news for us. Thanks a lot! :D
Comment: Is it really true that SE site policy discourages people sharing an IP address from "cross-voting"? I can see that if mods have to allow for that, it makes the job a bit more laborious. But assuming there would never be that many "genuine" cases, it seems unlikely it would become truly burdensome.
Comment: @FumbleFingers It's somewhat discouraged, because (1) it's hard for us to distinguish between sockpuppeting and genuine voting, and we'd prefer not to warn accounts when we shouldn't have, and (2) in such cases, the voting is often disproportionate, since you know the other person and you're more likely to vote for him/her than in other cases.
Comment: Yes, I see what you mean. Two people sharing an IP address probably share many other things, including attitudes to language usage. So all other things being equal, any upvotes for each other are inherently less meaningful than any random pair of users. The policy as you've set it out seems sound to me!
Comment: How does SE handle cases where an entire company or school is behind one public-facing IP address?
Comment: @MonicaCellio Same way, I think. They shouldn't vote for each other's posts.
Comment: @MonicaCellio Oh... I'm sure there is an answer to that, but I'm not the right person for this. Try asking a Team member. :)
Comment: @FumbleFingers Sharing the same IP doesn't automatically mean sharing the same language attitudes. When I go to visit my American friend, I am using her IP address, but her language attitudes are quite different from mine.
Comment: @Alenanno If your company's web proxy is well-behaved and uses the right forwarding headers, I would hope there would be no problem: it should be obvious that it is a proxy.
Comment: This is the first I've heard of this advice (to try not to vote for people sharing the same IP). So I suspect that much more casual users ill be unlikely to follow this advice, and also, it should be very difficult for casual (or even long time users) to be aware of sharing their IP address and who they might be sharing it with. This advice seems ostensibly correct but pretty difficult for users to know how to implement beside even knowing to implement it.


Is there any example of a long-standing mathematical conjecture whose resolution did not require advanced knowledge?

Question: Famous conjectures whose solutions took decades or centuries were usually resolved with the help of sophisticated theories and techniques unknown at the time the conjecture was first claimed. Is there any example where mathematicians didn't see a solution that after the fact was recognized as simple, basic or not very elaborated but people failed to see for a long time?
Answer: Sylvester's line problem (1893) was to prove that there exists no finite configuration of points in real projective plane such that every line through
two points actually contains at least 3 points, unless all points are on the same line. Sylvester himself found such a configuration in the complex projective plane.
This problem was quite famous, and was considered very difficult:
people compared its difficulty with the 4-color problem.
It was solved in 1944 by Grunwald, and a simple solution was obtained by Kelly in 1948. This solution occupies less than 1 page, and can be understood by any
high school student.
Edit. Another somewhat similar example is "Gehring's problem on linked curves" described in my answer to: this question.
Second edit. The so called BMV conjecture was proposed in 1975, a lot of sophisticated mathematics was used in attempts to prove it. It was proved by H. Stahl in 2011, and then I simplified his proof to 6 pages using nothing that was not well-known in 1900.
Comment: This may be a stupid question, but you wrote "Sylvester's line problem" and then "Silvester himself". Did you mean the same mathematician both times? Which is the correct spelling?
Comment: @Ross Presser: Yes, I meant John Joseph Sylvester. I corrected the misprint, thanks. But Grunwald is the same person as Gallai:-)
Comment: I think this is discussed in more detail in https://en.wikipedia.org/wiki/Sylvester%E2%80%93Gallai_theorem
Answer: Hanna Neumann conjecture was open for 40+ years and was solved in 2011 by relatively elementary methods independently and almost simultaneously by Friedman and Mineyev. The existing proofs actually proved the strengthened Hanna Neumann conjecture formulated in 1990 by Walter Neumann. All tools used in Mineyev's proof certainly existed in 1990 and much earlier.
Just this year the 80 years old Kaplansky unit conjecture was disproved by Giles Gardam, also by quite elementary methods.
Answer: Perhaps the poster child for this kind of thing is Apéry's theorem that ζ(3) is irrational, as described for example in Alf van der Poorten's paper, A proof that Euler missed (Mathematical Intelligencer 1 (1979), 195–203). Apéry's proof was highly ingenious and original, and not easy to grasp even after the fact, but it was short and used only techniques that Euler would have had no difficulty understanding (hence the title of Van der Poorten's paper).
Answer: Tiling of the plane by pentagons.
After the problem was discussed in Martin Gardner's "Mathematical Games" column in Scientific American magazine of July 1975, Marjorie Rice (an amateur mathematician) discovered four new examples.
Answer: Euler's conjecture stated in 1769 https://en.wikipedia.org/wiki/Euler%27s_sum_of_powers_conjecture
was resolved as disproven in 1966 using one basic line
$$27^5 + 84^5 +110^5 + 133^5= 144^5$$
https://www.ams.org/journals/bull/1966-72-06/S0002-9904-1966-11654-3/S0002-9904-1966-11654-3.pdf
There may be more similar cases from that time-period of counter-examples that are trivial to check, but hard to find.
Comment: Related MO question on how they might have found this: https://mathoverflow.net/questions/325192/intuition-behind-counterexample-of-eulers-sum-of-powers-conjecture.  There's a second paper that spells out how it was found.
Comment: Given that finding this counter sample required the use of a mainframe (something which wasn't available in Euler's time), does this qualify though?
Comment: I believe that holds some record for the shortest mathematical paper ever published?
Comment: @Voo It depends on how you view it, checking it didn't require a mainframe - but finding it would have been tedious without such help.
Answer: Four high school students here in the Netherlands constructed a $12\times12$ Franklin square with very extra symmetries. It wasn't completely Franklin though. The half horizontals didn't add up to half the whole value. I went on to develop a $16\times16$ completely symmetrical and magical $16\times16$ square. More magical (with the numbers $1-256$) it can't get. I made a $32\times32$ one too. With paper, pencil, and a calculator.
After they were on the news, a considerable wind was blowing in the magic square country. It was proven by direct calculation that a $12\times12$ Franklin square (like the one the students made) doesn't exist. If perfect $12\times12$ Franklin squares existed was a riddle up till then.
Answer: The Robbins conjecture was posed in the 1930s but not proved until 1996.  The proof was achieved by William McCune with the assistance of the automated theorem prover EQP. Unlike some other computer-assisted proofs, this proof was digestible by a human being, especially after simplifications found by Bernd Dahn.
Dahn's version of the proof is short and completely elementary, but still rather mysterious.  It shows that a certain identity is a formal consequence of the axioms, but via a sequence of manipulations that is difficult for a human to find, not so much because the proof is infeasibly long or laborious, but because there does not seem to be a clear conceptual idea to guide one's thinking from beginning to end.  The proof is simple enough that it could have been discovered without computers, but at the same time, it is not too surprising that it was first discovered with the aid of a computer.
Comment: @DescheleSchilder One can verify that each step follows logically from what has come before, but the motivation for taking the step is not always so clear. Many proofs that are discovered by computers have this flavor.
Comment: @DescheleSchilder I do not dispute your view of computers. Be that as it may, until McCune used EQP to search for a proof of the Robbins conjecture, no human was able to prove it. But after studying the computer output, humans were then able to write down what everyone agrees is a correct proof of the Robbins conjecture. Dahn's paper is only 6 pages long and it is possible for a human to follow the reasoning one step at a time without any recourse to computers. But the motivations for the steps are not always clear.
Comment: If there is no guiding concept then how can it be followed?
Comment: @DescheleSchilder, most proofs have an internal logic to them: it's obvious that each step gets you closer to the desired target.  This one, presumably, has one or more steps where the reader will go "why on Earth would you apply *that* theorem to *this* situation?"
Comment: But is it still a proof then?
Comment: Thats because a computer has no motivations. A computer doesnt truly discover like it cant truly play check. It just tries zillions of approaches and if one fits it fits, like a move in chess.
Comment: As for whether such a proof deserves to be called a proof, you may be interested in a recent article by Jeremy Avigad entitled, [Varieties of mathematical understanding](https://www.ams.org/journals/bull/0000-000-00/S0273-0979-2021-01726-5/S0273-0979-2021-01726-5.pdf).
Comment: It is remarkable that Robbin's conjecture involves binary operations. The computer was well equiped!
Comment: This reminds me of Lee Sedol's comments after examining AlphaGo games against himself and others. He said that its play revealed depths that had gone unnoticed by humans over Go's centuries-long history.
Answer: If by "long-standing" we mean a decade or more, then this sort of thing is fairly common in combinatorics. Short, elementary arguments can be very difficult to find. Here are a few examples that I happen to know about; there are many more.

The question of whether an aperiodic monotile or "einstein" exists has been implicitly around ever since Wang tiles were discovered in 1961. The first example was found in 2023, by Dave Smith, who was not even a professional mathematician. The proof that Smith's tile is an einstein is not that simple, but the bottleneck was finding a candidate tile in the first place, and the tile is very simple to describe (and was found by hand, not by a vast computer search).

The union-closed sets conjecture, which was posed in 1979, is still open, but in 2022, Justin Gilmer made a huge breakthrough, proving a slightly weakened form of the conjecture using no concepts that were not around in 1979.

Hao Huang's proof of the sensitivity conjecture was completely elementary but did not appear until 2019, whereas the conjecture was first posed in 1992.

The Dinitz conjecture was posed around 1979 and not proved until 1994, by Fred Galvin, by a completely elementary argument.  There had been some serious attempts to prove the Dinitz conjecture, e.g., by Jeannette Jansen, so it wasn't as though nobody knew about the conjecture.

The Stanley–Wilf Conjecture also lasted about 15 years before being proved by Marcus and Tardos, by an argument that could in principle have been given as soon as the conjecture had been posed.

Dvir proved the finite field Kakeya conjecture in 2008, about a decade after it was first posed, using a stunningly simple argument. No less a mathematician than Terry Tao had unsuccessfully thought about the conjecture. Dvir's use of the "polynomial method" paved the way for many other advances, such as the solution of the cap set problem, which was still quite elementary.
Answer: The Gaussian correlation inequality was first conjectured in the 1950s, and not proved until 2014 by Thomas Royen. As Wikipedia puts it,

The proof did not gain attention when it was published in 2014, due to Royen's relative anonymity and the fact that the proof was published in a predatory journal. Another reason was a history of false proofs (by others) and many failed attempts to prove the conjecture, causing skepticism among mathematicians in the field. The conjecture, and its solution, came to public attention in 2017, when other mathematicians described Royen's proof in a mainstream publication and popular media reported on the story.

Quanta magazine describes the reaction of statistician Donald Richards as follows:

Upon seeing the proof, "I really kicked myself," Richards said. Over the decades, he and other experts had been attacking the GCI with increasingly sophisticated mathematical methods, certain that bold new ideas in convex geometry, probability theory or analysis would be needed to prove it. Some mathematicians, after years of toiling in vain, had come to suspect the inequality was actually false. In the end, though, Royen's proof was short and simple, filling just a few pages and using only classic techniques. Richards was shocked that he and everyone else had missed it.


WordPress Plugin Development from Scratch. How?

Question: I would like to learn how to create a plugin from scratch, there are tons of tutorials out there on the internet, but they are either premium or not a reliable resource. would like to know which are the best resources available on the internet.
Answer: I guess this thread says nearly all
Answer: A very first advice from me will be: Don't follow the tutorials on the tutorial sites blindly they are full of bad coding practices.
Some of the resources that I follow:

Mark on Wordpress
Justin Tad Lock (You can also buy the copy of his e-book Professional Wordpress Plugin Development)
Otto on Wordpress
scribu's development blog

And here is the list of Specific tutorials that you should consider going through, some are old but are still valid.

http://markjaquith.wordpress.com/2006/03/04/wp-tutorial-your-first-wp-plugin/
http://www.devlounge.net/extras/how-to-write-a-wordpress-plugin
Answer: Additional to all above tutorials i recommend the following which best suites a beginner

https://premium.wpmudev.org/blog/noob-plugin-diary/
http://www.wpbeginner.com/wp-tutorials/how-to-create-a-wordpress-plugin/
https://wpadverts.com/blog/how-to-create-wordpress-plugin-from-a-scratch/
https://wpshout.com/making-first-plugin-live/

Best wishes
Answer: I'm trying to create a plugin too.
First place that I would like to suggest you to walk through is Writing a Plugin from Wordpress Codex.
Answer: Follow,What Hameedullah Khan Said.Additionally,I would like to suggest to you read the WordPress Codex.
http://codex.wordpress.org/Writing_a_Plugin
http://www.slideshare.net/davidfcarr/introduction-to-plugin-programming-wordcamp-miami-2011
Answer: I recommend this Wordpress Plugin Development series of video tutorials by Alessandro Castellani:
https://www.youtube.com/watch?v=0l7JTie_6jM&list=PLriKzYyLb28kR_CPMz8uierDWC2y3znI2
They're completely free, and they're great. He also has videos on other Wordpress related topics, including a fantastic 64-videos series on how to create a Wordpress theme from scratch. Really good stuff.


Can diastereomers form a racemic mixture?

Question: In my book, it says racemic mixture is the mixture of + and - optical isomers and it is optically inactive. This means enantiomers (optical isomers which are mirror images to each other) can form racemic mixture. But can diastereomers (optical isomers which are not mirror image to each other) form a racemic mixture?
Answer: The short answer is no.
A racemic mixture is defined as an equimolar mixture of enantiomers. Since each enantiomer rotates plane polarized light equally, but in opposite directions, the overall optical activity is zero.
Describing diastereomers as optical isomers is incorrect. Diastereomers are stereoisomers (that is, compounds that have the same connectivity of atoms but differ by the orientation of atoms in space) but are not enantiomers. In many cases, diastereomers are not even chiral (have no optical activity). If there's a mixture of diastereomers that are chiral, this is not described as racemic. Most likely that mixture would be optically active, but even if it was optically inactive, that would just be coincidental and not considered racemic.
The situation where a mixture is made up of two enantiomers in equal ratios is so common (and important) that it gets the special name of racemic.
Answer: It's not like "enantiomers (…) can form racemic mixtures" and "Who else can form racemic mixtures?"; it's by definition. Also note that the term "racemic mixture" is discouraged.

Racemic Mixture (usage strongly discouraged)
The term is confusing since it has been used as a synonym for both racemate and racemic conglomerate.
Racemate
An equimolar mixture of a pair of enantiomers. (…)
Racemic Conglomerate
An equimolar mechanical mixture of crystals each one of which contains only one of the two enantiomers present in a racemate. (…)

(as in Basic Terminology of Stereochemistry, IUPAC Recommendations 1996).


How to charge for banner ads in a web application

Question: I'm developing a web application which contains banner ads, and I don't know how to teach my clients how much to charge their customers for banner ads. Can someone help with a book or business strategy?
Comment: What do you mean by "how to charge"? Are you asking how much money to charge or how to implement an ad service and payment gateway?
Comment: exactly, i mean to how much money to charged for banner
Answer: I think this is a good article on the subject http://www.problogger.net/archives/2008/03/27/how-much-should-i-charge-for-my-advertising-space/.
The best thing to do is research what others in your industry are charging for ads of any kind on their websites and see what Google Banner ad rates go for on subject matter comparable to your site.
Once you have all of that you can create a guide for your clients to follow based off of what you have learned.
Answer: I ran a large non-profit site for several years and we got into the advertising game.  The problem is that there's no one-size fits all answer to this question.  Some factors that can influence your efforts:

The value of the ads is what the buyers will support.  That's the genius of Google AdWords--they set the value based on the demand and what people are willing to spend.
If you're asking $500 and not selling any banners, then the value obviously is less that your ask.  IF you're charging a dollar and don't have any inventory, then the value
is obviously more than your charging.  The value will change nearly constantly, so it's up to you to identify the "sweet spot" and follow its trends up and down.
Your traffic has a big effect on the value too, especially if you're charging based on CPM (cost per thousand impressions)  The more views you have, obviously the more you can charge.  If you're charging by click through (CTR) it's important to have quality, relevant ads that people are interested in.  As you put more time into advertising, will it negatively affect your content which could bring down your traffic?
Good advertisers (the ones who often control the most ad spends) demand metrics.  How will you provide this?  How will you audit it?  The best (read most profitable) sites give their advertisers real-time metrics.  Can you do this technically/financially?
How will you attract and service your customers?  If they are paying you good money, they will need "attention"  So, are you going to hire a staff to sell and service advertisers?  Remember, you're competing against sites who have an army of people pounding the pavement every single day.

To answer the original question, unless you formulate a sort of bidding system, you're likely going to have to rely on trial and error.  You'll get laughed at several times as you attempt to charge too much, or you'll overfill your inventory by charging too little, then be chastised for raising your rates.  It's the reason that I recommend to everyone that unless they're serious about supporting an advertising system to come back to reality (financially speaking) and get onboard with a system like AdWords or DoubleClick.  As developers and tech guys, there's so many other ways for us to make really good money!


Who is Satoshi Nakamoto?

Question: Who is Satoshi Nakamoto? I have heard about him and read his paper.
Why is he no-longer publicly involved in Bitcoin?
Comment: Voted to close as off topic. David Perry's answer covers pretty much all we realistically can know about Satoshi. This forum deals with issues arising from Satoshi's creation, not the person.
Comment: There's also a history of bad things happening to people who invent or promote disruptive technologies. [Phil Zimmerman](http://en.wikipedia.org/wiki/Phil_Zimmermann#Criminal_investigation_by_US_Customs), for example.
Comment: Nobody knows who is Satoshi yet
Answer: Satoshi Nakamoto is the elusive and private creator of bitcoin. In October 2008 he published the paper Bitcoin: A Peer-to-Peer Electronic Cash System (pdf warning) which is the basis of the bitcoin client/protocol. He has stated his nationality as Japanese and published a PGP key, has a sourceforge page and aside from that not much is known. It sort of follows that someone interested in creating a distributed pseudonymous online currency would be a very private person.
It is also suspected that Satoshi may be a pseudonym for any of a number of people involved in the original development - a mask used for safety and protection against legal persecution for the creation of such a potentially disruptive product. To that end, Satoshi may still be involved in bitcoin, although as you stated, not publicly. As with everything else about Satoshi, the reason for his lack of current involvement is unknown.
Comment: He also has a [bitcointalk profile](https://bitcointalk.org/index.php?action=profile;u=3) with a few hundred posts.
Comment: Are there public chat logs written by Satoshi?
Comment: Seriously isn't it common sense that one (or more) of the core developers is or knows who is Satoshi Nakamoto? E.g. Gavin Andresen, Pieter Wuille, Nils Schneider, Jeff Garzik, Gregory Maxwell etc
Comment: @Pacerier You may think so but, since Satoshi contributed under his alias there is no need for him/her to contribute otherwise.
Comment: Also, Satoshi sent the paper to the cryptographic mailing group on Oct 31, 2008. In your answer you mention it to be 2007
Answer: The two of the most important clues we have are:

Based on observing messages sent by Satoshi Nakamoto, he(/she/they) appear(s) to sleep at about the same time most Americans sleep
Satoshi Nakamoto owns about million bitcoins that have been worth over 64 billion dollars at one point of time, yet sees no reason to (and hasn't seen any reason to ever) convert that to an investment that has inherent yield, such as by selling bitcoins and buying diversified index funds. Most likely this is due to the fact that ever converting these bitcoins to something of value would risk revealing the identity, or it being pocket cash to whoever is Satoshi. Theoretically it could be of course that Satoshi Nakamoto has lots the crypto keys to access those bitcoins, however.

The two non-clues we have are:

Satoshi uses British English and has embedded references to British newspapers in the start of the blockchain
Satoshi uses a pseudonym that sounds like it's of Japanese origin

The reason these are non-clues are that anybody can use any language or dialect of a language, and anybody can invent any pseudonym. So most likely Satoshi wants that we believe he's British or Japanese in an attempt to conceal the identity.
Also there is some speculation based on Satoshi's code that Satoshi is not necessarily a single person but could rather be a team. This agrees excellently with clue (2), since a large team might have less incentives to convert the million bitcoins to something of an inherent value than a single person would. But it would have to be a pretty large team, though (otherwise the bitcoins in there per person would favor converting that to real money), and every member of that team would need to keep that same secret. Most plausible is that the team is in fact a state actor, since something that once was 64 billion dollars wouldn't be unused even if the team would be a large company for example. As an example, if we assume Satoshi is Apple (the most valuable company in the world), that company could have paid an extra dividend for one year (edit: an extra dividend for over 4 years, as Apple seems to pay less than 15 billion/year in dividends) by converting the bitcoins to cash. So claiming that Satoshi was Apple doesn't make sense. In a civilized world people working for a company wouldn't hide the existence of something that was once worth 64 billion dollars.
This leaves two most plausible explanations, the largest state actors in American time zones:

United States
Canada

Considering that United States has done a lot to improve encryption (and in some cases embedding backdoors to encryption algorithms), this is by far the most plausible explanation. 1 million bitcoins is pocket cash for United States. However, this theory would mean there's some reason for the state actor to conceal the identity of Satoshi, and we can't know (we can only speculate) why United States for example would create bitcoin in secret. At least the United States intelligence services seem to be capable of keeping information secret at least to some extent -- true, there has been an Edward Snowden but only one Edward Snowden.
But it wouldn't be impossible for Canada to be involved, however; after all, Canada is part of the Five Eyes alliance with United States and many other countries.
Personally, I think it would be an excellent idea for for example NSA to create a cryptocurrency that the majority of the world's population consider more private than cash, but that actually is far more public than for example any bank transaction. The claim that Satoshi = NSA is entire speculation, though, but the incentive is there. If you want to access all Internet traffic in the world (presumably to identify something illegal from it), doing something that might give you a view to a large portion of illegal financial transactions would be very useful. After all, those contain most of the interesting transactions, the ones you want to access anyway (plus a lot of "investors" wanting to be rich by buying Bitcoin and then end up losing a lot of money on that speculation).
Also, an observation: Tor has been created by United States, but publicly. Wouldn't be impossible for Bitcoin also to be created by United States, but this time privately.
But that starts to be more speculation and less facts, so I'll end the wild theories here.

Who is Satoshi Nakamoto?


cannot add web parts to page - sharepoint 2010

Question: I cannot add web parts to a web part page. If I click "Add web part" in a web part zone, there is a javascript error: Type mismatch, row 2, char. 13993, URI: http://portalsite/_layouts/wpadder.js?rev=hnGJJEMcU5XH%2BCq7PlSxJw%3D%3D
Is this a known bug? I tried more installations - no luck.
Thanks :)
Ravie.
Answer: Ravie,
I have seen this kind of behavior before, it is usually a result of another javascript error. In other words something else on the page is causing a javascript error which is preventing the SharePoint javascript from running properly.
Try using Firefox or Chrome to edit the page they tend to be more tolerant javascript errors


What is the proper translation for 'Dunnage', from English

Question: I can't seem to find an obvious choice by browsing product literature, which is my usual tactic. This is the concept I want a Spanish word for: https://en.wikipedia.org/wiki/Dunnage
Comment: I provided an answer, but I'm afraid is going to be an unsatisfactory one. If you could narrow a little bit more or give more context, probably better answers will be provided.
Comment: That was my confusion too, I'm creating a taxonomy of products and this category is so generic that there are many subtypes
Answer: Wikipedia itself has a link to the spanish translation: "Embalaje".
Comment: interesting answer; however, it would be good to expand it a bit more, since this is currently a bit more than a comment.
Comment: +1 Good response @Envite, it redirects to the actual answer and it's well explained there. I believe that the author of the question should have started by going to the Spanish version straight from Wikipedia as you suggest.
Answer: Se puede traducir como material de relleno o, en el caso de cargas, también material de aseguramiento.
Answer: Spanish for dunnage seems to be embalaje. Both Wikipedia and wordreference seems to translate it as such.
With the context provided

inexpensive or waste material used to load and secure cargo during transportation

embalaje or envoltorio would work:

recipiente o envoltura que contiene productos de manera temporal principalmente para agrupar unidades de un producto pensando en su manipulación, transporte y almacenaje

It could even be relleno if you are referring to the padding that sometimes is added to protect cargo (the foam that sometimes we call "corchopan" in Spanish)
Answer: As you are probably at the top of the taxonomic tree, why not name it with the common function?
If the sub branches refer to material used to just fill the spaces, maybe «relleno» can fit.
«Protección», «acolchado» or «amortiguación» if the case is to avoid damage or even (specially the latter two) movement.
If the taxon is very broad and there are branches of everything, just «embalaje» should do, if there are no separate taxons dedicated to packaging in general.
Comment: Commenting myself: maybe «protección» is the most suitable one? I'm reading a bit about dunnage and it's also used to keep moisture at bay too.
Comment: Again commenting myself: I see that my answer includes some answers already given by other users, so I guess they are who deserve the credit depending of which is your final choice.


Is there a way I could be forgiven if I intentionally eat non halal meat

Question: At the age of 16 I had this one friend in which we both didn't really think about our religion. One night we were at her house and we ordered food from a place that wasn't halal and I'm not saying it was her fault because I was fully aware of my actions and I knew it was haram yet I still did it but I sorta felt as if it was peer pressure from both of us. A year has passed now and I've basically lost contact with her but I've been giving that day a thought and I've never ate unhalal meat again but I regret that day so much and wonder if I'm gonna be punished for it even though I wasn't that aware of the punishments of doing haram things. Also I wanna know if there is a way that I could ask for forgiveness about that specific reason. Any sort of help is accepted thank you!
Answer: The answer to "Is it possible to be forgiven for [blah] by Allah?" is going to be "Yes." See Does Allah forgive every sin?

He who seeks repentance (from the Lord) before the rising of the sun from the west (before the Day of Resurrection), Allah turns to him with Mercy.
Sahih Muslim 2703

But the decision is up to Allah:

Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly fabricated a tremendous sin.
Qur'an 4:48

Two of Allah's names are The Repeatedly Forgiving and The Much-Forgiving, so we can expect that He will forgive generously.  To this end, the process of repentance is described here: How does one repent in Islam?
Answer: Salam. ask forgiveness of Allah and try your best efforts that dont repeate this mistake. Allah is the most forgiving, the most merciful.
Amirul-Mu'minin (a) said to the man who was prevailed by despair of God's mercy out of his many sins: "You, to despair of the mercy of Allah is the greatest sin that you have ever committed."
Quoted from Jami us-Sa'adat; part 1 page 246.
Answer: Is there a way I can be forgiven if I intentionally eat unholy meat?
If someone knows that this meat is forbidden and this food is forbidden, that is, he knows both the food (the subject) and the ruling that it is forbidden, yet he eats it, commits a mistake and disobeys, and this act is rebellion and disobedience. It is considered one of the divine commands and deserves its special punishment and punishment. And this sin has bad effects on human life.
Imam Sadegh (AS) says about the evil effects of sin: The effect of sin is that it deprives man of worship. Sometimes a person is afflicted with a sin during the day and as a result he is deprived of night life and night prayer. Unless he repents and corrects his past.
Ref: https://www.islamquest.net/fa/archive/fa1431


Bringing Money to the US from a Foreign Country

Question: I am an immigrant and I want to bring money from my country to the US. I know I have to declare the amount of money if it is more than $10,000, However I don't know the tax policy on my money. Do I have to pay tax on it and if yes, what is the percentage approximately?
Comment: I don't know the answer, but for most people the next tax year begins January 1. Suggest you contact an American accountant or tax lawyer and find out what moves you should make before January 1, especially if you are immigrating after January 1.
Comment: @GerardAshton US income tax applies to income.  Transportation of money that is already yours into or out of the United States does not count as income.
Comment: @phoog, as far as I know US income taxes do apply to income, but the funds may have been in some other form shortly before coming to the US, such as stock. So timing of changes may be important.
Comment: @GerardAshton that is true.
Answer: US Customs and Border Protection says:
Money and Other Monetary Instruments
You may bring into or take out of the country, including by mail, as much money as you wish. However, if it is more than $10,000, you will need to report it to CBP. Ask the CBP officer for the Currency Reporting Form (FinCen 105). The penalties for non-compliance can be severe.
"Money" means monetary instruments and includes U.S. or foreign coins currently in circulation, currency, travelers' checks in any form, money orders, and negotiable instruments or investment securities in bearer form.
Answer: Imports of cash or cash equivalent to the US are not taxed.
Green card holders are subject to US income tax on their worldwide income, however, so if you acquired any of that money while you were a US permanent resident, you will have reported it on the tax return for the appropriate year, and it will already have been taxed.


Cognito form not showing confirmation

Question: I just created a complex form using Cognito Forms and when testing the form using the URL and the embed code, form data submits but nothing happens on the page. The confirmation message never appears and the URL never redirects (I have tried both options). Anyone else run into this and have a solution?
Answer: I am a developer for Cognito Forms.  We recently released support for conditionally visible fields, sections, content, etc. based on custom calculations on forms.  As part of this we also conditionally hide these fields when sending email notifications with submitted form data.  Unfortunately there was a small bug related to conditionally hidden content fields, which your form uncovered (because it was quite complex!).  So while the entries are being saved, the email notification is not being sent and the confirmation is not displayed.  The fix is currently being tested and will be deployed soon.  You can avoid the issue for now by not sending detailed email notifications.
Thanks for also submitting this as a bug report!  Bug reports through our product are the appropriate way to report issues, as this site is intended as a forum to ask questions about how to use Cognito Forms and other web apps to solve problems.
Comment: @pnuts, thanks for asking!  This issue was resolved back in May and I should have updated this answer accordingly.
Comment: Incidentally, when we've reached out to a couple of users asking them to mark questions as answers they have had problems signing up correctly.  It sounds like they just signed up after the fact with the same email address and ended up creating a new account not linked to the question.  Also, one did not realize the checkmark was clickable and should be clicked to mark the answer as accepted.  Not sure what can be done to help, but thought I should pass this on since we are generating a lot of first time users for StackExchange.
Comment: @JamieThomas If you run into this situation, please ask the user to use the "Contact Us" link at the bottom of the page and have them include both userIDs in the request.  Thanks for taking notice of this.  As moderators, we can't do the merges ourselves, but the Community Managers are able to do them via that form.
Comment: (To the flagger of the comment, I had to decline the flag to keep the comment in place.  Sorry.)

Cognito form not showing confirmation


Is that built in allowed?

Question: I have recently created a coding language called Valyrio. I have also posted a proposal for a question in the Sandbox. I have a problem though. It has been well-established that any builtin or language created after the code-golf has been posted is not allowed and any answer after this is non-competing. However, I added a builtin to Valyrio after I posted the Sandbox proposal that can do this challenge. The question, as of yet, has not been posted as a code-golf problem. Does this mean I can use the built in to complete the challenge or does it violate the non-competing rule?
Comment: [There is a loophole for that](http://meta.codegolf.stackexchange.com/a/5772/62574). I think it depends on how much your answer relies on the built in. If your answer becomes boring or unfair because of the built in, I wouldn't include it. But if it's still a nontrivial solution, I think it should be fine.
Comment: The question is the first one if ordered by active. The built in is the symbol `ß`. It is easiest to explain if you read the Stack Commands doc on the GitHub repository.
Comment: @JackBates The loophole is about creating a builtin with prior knowledge of a challenge. As you knew about the challenge before adding the builtin, it is not allowed.
Comment: Thanks for the clarification! I wasn't sure if it violated the rules.
Comment: Considering that it's your challenge, you may not wish to answer it anyway, as it could discourage others from answering.
Answer: It depends
(But based on what I've seen of your built in, probably not)
There is a loophole for creating/modifying a language while it's in the sandbox. Dennis' comment gives 2 main reasons why this is not allowed: It's unfair and boring.
Here's where the ambiguity comes in. If your built in makes your answer boring, you probably shouldn't post it (or you could include it in another answer of the same language, If you felt the need). If your built in makes your answer unfair (but not uninteresting!), you may want to post it as it's own answer, but noncompeting.
Or you could just leave it out, especially if your answer would only be a few bytes.
From (briefly) reading the documentation, It looks like your answer would be very short due to the built in. In that case, I would not post it, as it most likely falls under both categories.
The bottom line is, If your answer is nontrivial and interesting, then go for it. Otherwise, just let it pass.
Comment: Thanks. This really cleared it up!

Is that built in allowed?


Why are the prices of some commodities (e.g. oil) more volatile than others?

Question: Why are the prices of some commodities (e.g. oil) more volatile than others?
Comment: partially due to speculators creating "artificial" demand.
Comment: Oil is primarily due to speculation, and not due to shortage of supply as everybody assumes. Banks were pointing at the price reaching $200/b, because of their in house bets on price speculation.
Answer: The volatility of a commodity typically depends on how volatile is demand and how flexible is supply.  In the case of oil, it is more volatile than in the past because most of the spare capacity from OPEC has been taken out of the system.  Commodities whose demand responds similarly to economic shocks but with much greater excess supply, such as natural gas in the United States, are considerably less volatile, although a few years ago when supplies of nat gas were tight in the US, volatility of nat gas was greater than volatility of oil.
Answer: Any number of reasons.
Technically, large positions being bought/sold in the market can trigger others to follow.
Fundamentally, disruptions in supply can trigger uncertainty or volatility in the markets, especially with oil.  A good chunk of the world's oil is in places that doesn't have the best track record for peace and prosperity, shall we say?  But even under the best of times, a hurricane can take out refining capacity and the price can spike up.
As for other commodities, there are other things can can disrupt supply: crop failure, flooding, mines collapsing, the works.
Answer: Prices are driven by the demand for a commodity and the availability of that commodity. For some commodities, projecting demand is easy or irrelevant.
Take gravel as an example... if I order 50 tons of gravel, I find a supplier who send me whatever is in his warehouse and if this is insufficient, he digs it out of a quarry and puts it on a truck. No big deal -- the cost of generating more supply is low. (as is the cost of holding excess inventory... rocks don't go bad!)
Lettuce is a little more complicated. Based on past orders and growth trends, you can pretty easily gauge demand. The trick is, delivering the supply... all sort of things like weather, bugs, disease can disrupt my ability to send you sufficient lettuce. The cost of getting additional supply is moderate -- I just truck in lettuce from California.
Gasoline is tougher because demand shifts based on season and price elasticity. And the supply chain is very long... I live in NY, so most of my gas comes via a drill rig in Saudi Arabia or the Gulf to a refinery in New Jersey to a tank farm along the Hudson River to my local gas station. At any point in that chain, a critical path issue can result in a supply constraint or overage, and those problems have cascading effects on price.
So to answer your question, the price is volitile because there is alot of demand, a complex supply chain as well as a number of independent variables (currency exchange rates, weather, etc) that can affect the price.
Answer: Prices and volatility for a commodity are driven by changes in supply and demand, more often the latter, since supplies are usually "fixed" in the short term.
Oil is a particularly volatile commodity because it is genuinely critical to so many things, transportation, manufacturing, electric power, etc. Because of this fact, it has numerous parties ("agents," in economic language) monitoring available supplies. This includes whole governments, that sometimes build up strategic petroleum reserves.
Because of the involvement of so many parties (actual and potential), trading in oil is a "crowded" trade, which produces volatility. Imagine the back and forths of a bunch of people at a party in a crowded room.
Comment: This answer happens to be demonstrably wrong, it is a shame it is marked with a check here.  Fresh water is genuinely critical to so many things, and demand happens to fluctuate quite a bit, but price remains relatively constant because supply is plentiful.  There's no shortage of parties monitoring supply of fresh water, too.  Crowded trades, by the way, have to do with valuation, not volatility.
Comment: sheegan: The comment was that prices are driven by CHANGES in supply and demand (and the implication was, over a critical region). Water is, for now, OUTSIDE of a "critical" region (being plentiful). But if demand continues to rise faster than supply, it MAY enter a critical region and have its price be market driven.
Comment: Demand always equals supply, so changes in demand also equal changes in supply.  A shift in demand causes price to adjust in order for supply to meet demand.  The difference between water and oil is that the next X gallons/barrels cost a lot more (relative to current prices) for oil.  As for whether a commodity is in what you label a "critical" region, that seems subjective and ill-defined at best.
Comment: Projected supply affects more than actual supply.  An expected shortage that does not manifest causes a greater increase than an actual unexpected one.  Demand has very little impact as has been seen in recent gas prices.  Low demand did not reduce the price of the gas.  But expected shortages that never materialized have cost us over a 50cents a gallon for over a year now.
Answer: Could speculation make an item more volatile?
Speculation actually reduces volatility.  Speculators purchase an item believing that the price of the item will go up in the future.  The speculator is predicting either increased demand or decreased supply.  When the price does go up the speculator sells the item.  By selling the item at the higher price the speculator increases the supply of the item into the market and the price of the item will not rise as fast due to the additional supply of the item supplied by the speculator.  In this way speculators reduce volatility.
Why is oil more volatile?
First, the unit of measure must be taken into account.  Oil priced in US dollars is much more volatile than oil priced in gold.  This is due to the rapidly changing value and demand for the US dollar (USD).  The chart below shows the volatility of oil priced in US dollars versus the volatility of oil priced in gold.  The standard deviation of the price in USDs is around 29 while the deviation when priced in gold is 0.015.

Secondly, some of the major oil producing countries have stopped, or attempted to stop, accepting US dollars for oil.  Iraq in 2000, and Iran in 2009.  This increases volatility (in USDs) since buyers must quickly dump some of their USDs in an attempt to obtain some euros to purchase oil from these major producers.
Thirdly, destroying the infrastructure used for oil production can cause significant disruptions in the supply of oil which will increase volatility.
Comment: LOL  A picture is worth a thousand words?
Comment: seems like speculation would, in your example, only reduce volatility if the speculators are right.  if a speculator guesses wrong (supply goes up, or demand goes down), the price goes down and the speculator will sell to stop her losses.  This will supply oil at just the time it isn't needed.
Comment: "This will supply oil at just the time it isn't needed." If oil is not needed then the speculators would not have been able to sell it. The fact that they can sell it shows it is needed.


Delete parts of a grid outside of another object

Question: I created a grid (as multiple curve paths) which is in and outside of a sphere. When I'm trying to delete all parts outside with the Boolean Modifier, it says "Cannot execute boolean operation". How can I solve this?
Comment: The Boolean modifier most likely will fail dealing with intersecting geometry, like one on intersections of the grid lines, see http://blender.stackexchange.com/questions/5140/cannot-execute-boolean-operation-when-subtracting-several-spheres-and-cylinder. It might be necessary to delete that intersecting geometry of grid before executing Boolean which can be quite cumbersome task.
Comment: I created a extra topic with this problem: http://blender.stackexchange.com/questions/48159/fill-curve-cube-without-intersecting-parts
Answer: The problem is, that you need a proper (non-manifold) mesh to do the Boolean operations with. The method you used to create your "Grid Cube" doesn't help here because it doesn't prouce one. You could check your mesh in Edit Mode hitting Ctrl Shift Alt M with the Mesh Select Mode set to Edge or Vertex.
Here's a better Method to create your Grid-Frame-Cube:

Create a small cube in the corner

Add a default Cube (2x2x2) in the Center and name it miniCube
Position your 3D Cursor to the front bottom left corner by selecting the Vertex in Edit Mode and use Shift S, Cursor to selected
Pivot around the 3D Cursor and scale your Cube (S) by 0.25.

Duplicate this small cube twice, name one Grid and one inner, then hide the original miniCube or move it to another Layer as a Backup. You might need it later again to play around with the following Bevel settings.
Select the inner Cube and in Edit Mode select every Vertex (A), then use an Edge Bevel (Ctrl B) of 0.25.
Select the Grid Cube and add a Boolean Modifier with the inner Cube as Object in Difference mode. (This will cut out the inner part, basically only leaving the grid-frame)
Add three Array Modifiers, one for each Axis to the Grid Cube. This basically creates the grid-frame-like Cube structure you created but with a proper geometry.

Set the Count to 4
Set the Relative Offset to 0.0 on each but 1.0 for one axis: x for the first Modifier, y for the second and z for the third.
Check Merge

Now you can add the Boolean Modifier to the 2x2x2 Sphere in your Center with an Intersect Operation and the Grid as its Object and it will work fine:

You could of course play with the Bevel of your small cube before to get your grid nicer looking. You could use more Segments or change the Profile from 0.5 which is "flat" to a smaller number like 0.25 to get a more rounded grid-frame. Its settings are available in the panel in the Toolbar once you confirm the Bevel before doing any other operation or by hitting F6.
Comment: Related: http://blender.stackexchange.com/a/46809/2843


On a Micro 4/3s camera with a Speedbooster adapter, does a 50mm lens still effectively become a 100mm lens?

Question: I'm admittedly rather new to the world of interchangeable lenses, and have just purchased a Panasonic GH4 and adapted it to a full frame lens with a Metabones speed-booster. I've been using a 50mm lens, under the impression that what I was seeing through the viewfinder was truly a 50mm shot. I have since read that a Micro 4/3s sensor shoots everything effectively 2x the focal length of the lens, so is my 50mm truly acting as a 100mm lens, despite my adapter? I apologize for my ignorance, and appreciate any light you can shed.
Comment: What specific lens is your 50mm lens? What specific mount on each end is your speedbooster?
Answer: You speak of two different factors.
The 2x crop factor equivalence of 4/3 sensors is based on the sensor size. The 4/3 camera sensor has a crop factor of 2, meaning it has a diagonal 1/2 the dimension of a full frame camera, so the smaller sensor "crops" the field of view seen to be only 1/2 of the field of view (1/2 of the diagonal dimension).  The lens is not changed in any way by mounting it on a smaller sensor. The reduced field of view is instead due to the smaller sensor size (too small to capture the full image from the lens). This is a very simple concept. The cropped sensor means the image is cropped smaller, and the smaller image is missing the outer extents of field. See https://www.scantips.com/lights/cropfactor.html about Crop Factor.
The Panasonic GH4 has a 4/3 sensor with crop factor of 2.  That means that its smaller sensor  sees a smaller cropped field of view, which means its 50  mm lens sees the same field of view that a full frame camera with a 100 mm lens would see (if standing in the same place). The 100 mm equivalence describes the full frame camera, NOT the 4/3 camera. The 4/3 camera in this case is still using a 50 mm lens. It sees what it sees, but we can say that the cropped smaller field of view that it sees does compare to a full frame sensor with a 100 mm lens (if 2x crop factor).
If both cameras used the 50 mm lens, the smaller sensor simply crops the view smaller than the larger sensor would see (uncropped).
New subject:
The Metabones is an optical adapter, with glass optics in it, which does change the effective focal length of the lens combination. Its 0.7 factor means the lens combination becomes 50 mm x 0.7 = 35 mm equivalence. The field of view is 1/0.7 or 1.4x wider (wider than what this sensor saw without the adapter).
So the 2x crop factor 4/3 camera, if using a 0.7x optical adapter, would have a equivalent crop factor of 2 x 0.7 = 1.4x crop factor. The meaning is that the field of view (4/3 with adapter) then would compare to a full frame camera using a 50 x 1.4 = 70 mm lens.
It crop factor does NOT mean it becomes a 70 mm lens. The sensor cannot change the physical lens. It remains a 50 mm lens, but now with 0.7 adapter that does change the combination to become a 35 mm lens combination. That is the numerical data that applies.  But the 2x crop sensor means that the field of view this combination sees compares to a full frame camera if using a 70 mm lens. But again, it certainly is not a 70 mm lens on the 4/3 camera. The lens is clearly marked 50 mm, and the adapter is clearly marked 0.7x.
So this lens on the 4/3 body remains a 50 mm lens with an 0.7x optical adapter making it act like a 35mm lens (on a 4/3 body). Due to crop factor, the field of view acts like a 70 mm lens on a full frame body. But the combination acts like a 35 mm lens on the 4/3 body.
If you have years of past experience with full frame bodies and lenses, this is good information to know, your experience can know in advance what the 4/3 body will do then.
If not familiar with full frame use, then this full frame equivalence probably has little meaning to you.
We do think of the crop factor as multiplying the focal length to a longer equivalence. It doesn't of course (except as compared to full frame), but it would superficially appear that we do get telephoto pictures from the cropped sensor.
However, the same effect is true of any cropping.
Take any image in your photo editor, and zoom in to double size.  It then shows a reduced (cropped) field of view, but the smaller image is now enlarged more to same original size again. This necessary greater enlargement of a cropped image does appear as if a telephoto effect, but it is only a smaller image which is necessarily enlarged more back to same size. The enlargement is done afterwards, but it is a reduction in the camera.
Comment: Note that there is also a 0.64X / +1.33 stop Metabones Speedbooster compatible with the GX4 as well as the 0.71X / +1.0 stop versions.
Answer: Since the beginning, camera sizes have risen and shriveled based both on improvements in technology. As the 20th century dawned film had sufficiently evolved making miniature cameras possible.  The first truly functional miniature was the Leica designed in 1913 and marketed in 1923. This still camera accepted 35mm wide motion picture film which by that time was abundant. Leica's chief engineer, Mr. Barnack, set the format size at 24mm height by 36mm length. This format became the de facto standard for miniature cameras. Today's top gun digitals, classed as "full frame", embrace this format size.
Technology marches on. Cameras continue to shrink. The 4/3 format measures 13mm height by 18mm length. You need to know that the vast majority of photographers we hold in esteem were reared on the full frame 35 mm film cameras. They know everything about how this camera responds when different focal lengths of lenses are mounted. When they transition to smaller formats, might they not appreciate a helping hand?
Crop (magnification) factor to the rescue:  To find equivalency of lenses between formats, we evaluate the corner to corner measure of one to another. Thus  -- the full frame measures 24mm height by 36mm length. Its diagonal measure is  43.3mm. The 4/3 format measures 13mm height by 18mm length. The diagonal measure is 21.6mm. Now we divide to find the crop factor 43.3 ÷ 21.6  =   2. Viola! The crop (magnification) factor is 2.
What does this tell us? If we mount a 25mm lens on a 4/3 camera, the angle of view delivered will be the equivalent of 25 X 2 = 50mm. Another way to use this factor, we mount a 200mm on a full frame, what is its equivalent when using a 4/3 camera? Answer 200 ÷  2 = 100mm. Also, the inverse of the crop factor 2 = 1/2 X 100 = 50.  In other words the 4/3 is 50% of the size of a full frame.
I personally don't like this concept of crop factors. We did not use them when we transitions from 4X5 view cameras to the smaller formats. Besides, you younger folks likely never became attached to the full frame format that is so revered.


SQL Server - NOLOCK vs. READONLY connections

Question: For SQL Server 2008 and above, should (NOLOCK) be used on each table of a SELECT statement even if the connection is configured as READONLY?
Answer: Locking is mainly used to help writes and reads write and retrieve data that is ACID compliant.  Thus a 'read only' query can have several layers of locking.  By default, MS SQL Server uses pessimistic locking where as Oracle uses optimistic locking.  That means in SQL Server reads by default will always block writes and vice versa.  In Oracle's default isolation level, reads do not block writes.  Thus unless you are familiar with your isolation level and if you're OK with dirty reads, then technically could.  However that doesn't mean you should.
Read up on some of the issues you'll face with NoLock and alternatives.
Copy/paste:

NOLOCK Effects
What are the effects you need to worry about? Well, others, like Andrew Kelly, have described this before, Paul White digs quite deep into it, these search results are quite telling, and Kendra Little even has a video about it… but I'll point them out anyway:
"Dirty read" – this is the one most people are aware of; you can read data that has not been committed, and could be rolled back some time after you've read it – meaning you've read data that never technically existed.
Missing rows – because of the way an allocation scan works, other transactions could move data you haven't read yet to an earlier location in the chain that you've already read, or add a new page behind the scan, meaning you won't see it at all.
Reading rows twice – similarly, data that you've already read could be moved to a later location in the chain, meaning you will read it twice.
Reading multiple versions of the same row – when using READ UNCOMMITTED, you can get a version of a row that never existed; for example, where you see some columns that have been changed by concurrent users, but you don't see their changes reflected in all columns. This can even happen within a single column (see a great example from Paul White).
Index corruption – surely you are not using NOLOCK in INSERT/UPDATE/DELETE statements, but if you are, you should be aware that this syntax is deprecated and that it can cause corruption, even in SQL Server 2014 RTM – see this tip for more information. Note that you should check for the hint in any views that you are trying to update, too.
Read error – because the underlying data could be moved or deleted during your read.
Answer: Most of us here would say that WITH (NOLOCK) should be used sparingly, if at all.
I'll assume that you're asking if WITH (NOLOCK) serves a purpose on a database in READONLY mode. WITH (NOLOCK) is most commonly used to ignore exclusive locks on tables during a query. With no updates, inserts, or deletes being possible, one would presume that a READONLY database should have no exclusive locks being taken (unless some SELECT query does so explicitly). So, practically speaking, using WITH (NOLOCK) in queries against a READONLY database should produce no useful benefits.


Tribute to Stan Lee in The Flash?

Question: In the latest episode of The Flash, All Doll'd Up, we see Ralph aka Elongated Man swinging over buildings, throwing arms around like Spider Man does his web, while carrying Iris on his back. Just before that, he said he saw this in a comic book. It sounded to me like a tribute to Stan Lee. Am I right in thinking that, or is this just a coincidence?
Comment: Arrowverse specially Flash is famous for referencing other property specially marvel, just a coincident with Stan Lee death, some references; https://comicbook.com/marvel/2018/04/06/arrowverse-tv-the-cw-easter-eggs-marvel-mcu/#4 but sure;y not a  bad question +1
Answer: I'm going to go out on a limb and say no.
Stan Lee died on 12 November, and the episode premiered in the US on 13 November. There is no way they could possibly have rushed out such an indirect, CG-intensive tribute in such a short space of time.
Most likely, the episode was written months ago, the scene is a reference to Spider-Man rather than Stan Lee, and the fact it aired only a day after his death is just a tragic coincidence.
Comment: Yes, I agree the episode was written and filmed way in advance. But is it possible for the episode to have been re-scheduled or was it a complete coincidence it aired at this time?
Comment: If the show consisted of random disconnected episodes like (say) *Family Guy*, then it might be possible, but I believe *The Flash* has continuous arcs, and shuffling episodes around like that would have caused continuity errors. So again, probably not.
Comment: @vlaz: the CW usually releases the synopsis and episode titles of *The Flash* weeks in advance. We probably knew that the episode of this week was about Rag'Doll before (or shortly after) the season started. There was no episode last week because of the elections. So impossible that episodes have been switched.

Tribute to Stan Lee in The Flash?