How do I play B# and C at the same time?

Question: Several times now, a piece I'm playing has asked me to play B# and C or E# and F at the same time. I'm very confused at what's this supposed to mean? The key is G minor/B flat, or 2 flats. Can anyone explain?
Comment: Can you post a picture or scan of the the section of the music in question?
Comment: The two flats in the key signature are Bb and Eb so I highly doubt that there are any B# or E#. Either there is an error in your score or something is being misinterpreted. Is it possible you're reading a clef wrong?
Comment: Are you sure it's B# or E# and not a B or E with a Natural symbol?
Comment: Natural signs look very similar to sharp signs, especially in some fonts. And a B with a C may occur more often that a B# and a C - although it will sound dissonant.
Answer: Given that the key signature has B♭ and E♭, I highly suspect that the piece is asking you to play B natural and E natural. Musically, it would be highly unusual for a piece in a key signature with flats to ask for those notes to be sharped. Doubly so given that the C and F aren't sharped. In the circle of fifths, F and C are the first notes to become sharp, while E and B are the last to do so.
While it is likely a case of poor editing as Dom suggests, if it's from the Renaissance or Early Baroque, it could actually be a faithful copy of the manuscript. It took some time for accidental signs to become standardized to what they are today, and flat/sharp symbols could conceivably represent flat/not-flat (i.e. natural) versions of the note. In fact, the modern sharp and natural symbols both derived from the same square-shaped b symbol ("hard b"), as opposed to the rounder b symbol ("soft b") that became the modern flat sign.
That said, if the piece were legitimately asking you to play both a B♯ and a C natural (as extremely unlikely a situation as that would be), then they would simply be played as the same pitch.
Comment: I spend time transcribing 18th Century music into abc, and it's very common to see this notation which is confusing to modern eyes. As Caleb says, the key signature of Bb and Eb has flattened the B and E, and the subsequent B# and E# are therefore telling you to raise the B a semitone to B natural, and the E a semitone to E natural.
Answer: It is not strange at all. According to the AB guide to music theory by eric taylor, B# and C are a type of unison called diminished second. I believe there can be many more situations like this. I believe if i were to pluck a C note and then pluck the B below that but on another string, but bend that B up to the pitch of C then it will be called a sharpened B because the pitch C was already there and the pitch B was there and moved to a pitch en-harmonically equivalent to C creating a unison of a diminished second with the notes B# and C.
To test this yourself tune your high E string a semitone up to F and pluck it and pluck the E on the 6th fret of the 2nd string then bend it a semitone up to the same pitch as F, you will now have the notes E# and F as a type of unison called diminished second.
It would be important to note a more accurate diminished second is by saying an F note bending a semitone down to E while and E is already there will create a unison of E and Fb (F flat) called diminished 2nd because the minor second of E being F was lowered a semitone. This may not be done on an acoustic guitar without some contraption to bend 1 string down while another sustains without changing pitch so B# and C can pass as a unison called diminished second where you play enharmonic equivalents in a rare case.
I would have to see the music sheet to tell you for sure whats happening in your situation but usually these enharmonic equivalents mean for you to play unisons on 2 separate strings.
Comment: This question is for piano where you can't play a unison at all.


Cactus growing white hard coating

Question: One of my cactuses has been gradually growing a white coating, and the lower outgrowths seem to be shrivelling up and fading, I first noticed this about a year ago and it hasn't stopped no matter what I've tried.

I have no idea if it's mould or some type of sunburn or disease but it seems to have just affected this one, which I treat the same as my others that are growing fine. I was considering taking off the healthy looking top part and just starting again from this, but I was wondering what might have caused this or if it is at all salvageable. Any tips or ideas appreciated, thanks!!
Answer: I would separate this guy from your other plants for now.  Just in case this is sclerotinia or white mold you need to get it away from all plants, soils.  If you could wiggle the top of that plant where the white coating is on the highest joint showing the white coating...how firm does it feel?  Wait until you've got more answers from my team mates, okay? But do remove that plant until we are able to ID this for sure.
If it wiggles more than a healthy joint, let us know. If this is sclerotinia just one spore could kill all your plants.  Otherwise this could be a normal thing for cactus, I am hoping I am wrong.  Not the first time I've been wrong.  Sclerotinia is one horrible disease.  You might have brought it in with soil or store bought plants or someone's home plant. Those joints being the first to be compromised could be showing sclerotinia.  Let's hear what others have to say but remove this plant from the room until we ID this problem.  Otherwise, if you separate the healthy top from that highest joint you might find these weird rat turd looking things.  That IS sclerotinia.  If you do that you have to bag everything and anything that that plant has touched or at least use bleach to clean.  sclerotinia
Comment: Thanks, I've separated it from the others for now, I've never seen sclerotinia before but it doesn't seem like its rotting at all. All joints are firm and normal, the coating is thin but brittle and seems like it's only affecting the outside. Hopefully it's not this, I'll wait to see if anyone else has any ideas before I try anything :)
Comment: Excellent.  I've not seen sclerotinia on cactus but the pics on the internet show it is indeed possible.  This could possibly be normal for cactus, I've seen this white brittle coating before what concerns me is the reduction of diameter at these joints.  I sure hope I am wrong.  Sclerotinia is one bad ass disease.  Its reproductive organs are amazing.  They are just like big rat turds.  I'll ping some of the others here...cross my fingers!
Answer: It almost looks like normal corking, but when I look closer, the two pads on the bottom right don't look good. It also looks like it is beginning at the joints on the pads further up the stem.
Is this plant variegated? I may be mistaking the yellow variegation for the same problem as below.
The good news is that it doesn't look like an insect problem.
On the main stem at the bottom, it looks like the cuticle is separating from the layer below. This can be indicative of corking or some disease/mold/fungus.
From the pictures the soil looks very rich and too wet. What I see may not necessarily reflect reality, it's just what I see in the pictures. Has it just been watered?
If this were my plant I would:
Grab a good, non-affected pad now to root in case whatever this is spreads. The get some anti-fungal/anti-mold spray and soak that thing. Moving it away from any other plants is probably a good idea too.
Keep us posted, I'm interested in seeing how this progresses.

Cactus growing white hard coating


French Nationality - Surrendering Indian Passport

Question: I have French nationality since birth (born in 1991). However due to various reasons, I have an Indian passport and no French passport. I have not traveled outside India with my Indian passport either. I need to understand the process to surrender my Indian passport and obtain a French passport.
Comment: No idea about any special rules India might have but as far as the French authorities are concerned, surrendering your Indian passport is not necessary and largely irrelevant. The most important question is how to establish that you are in fact a French citizen. Then you would approach a French consulate to obtain a passport and/or a "certificat de nationalité française". If that somehow implies that you have lost Indian citizenship or you wish to renounce it, you can always take care of that after you have obtained your French passport.
Answer: That's two, non-related, processes. If you are indeed French, you can apply for a passport at the nearest French consulate. You'll have to go there, you can't do this by post - they will take your fingerprints.
As for renouncing your Indian citizenship, it is not required by France. And, more importantly, if you're planning to stay in India, you would need a visa. Better keep your Indian passport as long as you live in India. You would need it too, to exit India - for India, you're an Indian citizen, and there's no French citizen living there with your name.
Comment: I believe that getting a French passport would cause loss of the OP's Indian citizenship.
Comment: It is true that, logically, he hasn't voluntarily acquired a foreign nationality. However, according to India's Citizenship Rules, he is considered to have voluntarily acquired a foreign nationality if he gets a foreign passport. Citizenship Rules, Schedule III, #3: "The fact that a citizen of India has obtained on any date a passport from the Government of any other country shall be conclusive proof of his having voluntarily acquired the citizenship of that country before that date. "
Comment: @dda Whether the Indian government is aware of it is irrelevant to the OP's citizenship. To grasp the distinction, consider what happens if the Indian government becomes aware of it at a later date: They will consider the OP to have ceased to be Indian on the date they got the passport, not on the date they were found out. Of course, they might get away with it in the meantime and maybe that's all they need but this can also have very real consequences, e.g. on the citizenship of their children.
Comment: Not necessarily - if the OP is already French, having or not having a passport doesn't change anything. And getting a passport won't mean the Indian government is aware of it. However, using that French passport to exit India would cause all kinds of problems.
Comment: As I said, obtaining a French passport doesn't mean the Indian government is aware of it.


How to remove Birthdays from Google Calendar

Question: How to delete Birthdays from Google Calendar? There is no link in Calendars settings, which allows to unsubscribe from Birthdays calendar in Google Calendar.
Answer: Here is a solution how to remove Birthdays from Google Calendar:

Cogwheel icon button
Settings
Calendars tab
Browse interesting calendars link
More tab
Unsubscribe link next to Birthdays calendar

Execution of these steps will unsubscribe you from Birthdays calendar in Google Calendar.
Comment: This method no longer works. *Birthdays* is not available in the *More* tab anymore :(
Comment: I suppose my post did help you, and that's great.
P.S. Me either don't understand what was the problem to add «Unsubscribe» link to this calendar, like, in case of any other calendar.
Comment: Yup, that is one of the most convoluted, circuitous ways I've ever seen of disabling a feature.  Very un-Googlish.
Answer: Unfortunately, it seems you can no longer unsubscribe from the Birthdays calendar.1
The best you can do is not display it.2 Find it in the list of calendars to the left and click it so the colored square blanks out. That indicates that the events for that calendar will not be displayed in any calendar views. As long as you don't turn it on (and can ignore the unused entry in the list of calendars) it will never bother you again.
Commentary: I don't understand this move by Google. This is something that Facebook would do. Certainly there must be people who don't want to use their calendar to keep track of birthdays and anniversaries.

1 Since the description says "Displays birthdays of people in your Google+ circles and Google Contacts. Also displays anniversary and other event dates from Google Contacts, if applicable." I suppose it might still be possible to unsubscribe if you don't have a Google+ profile, but I doubt it.
2 Your other option would be to go into all of your contacts and remove any dates in their birthday or anniversary fields, and also remove all people from your Google+ Circles. Not very practical.


Am I eligible for the stimulus check, and if so, why haven't I received it?

Question: In 2018, I was claimed by my parent on their tax return. But in 2019, after I graduated from college, I filed my taxes with a single status and made about $28K. My parent did NOT claim me in 2019. Am I eligible for a stimulus check? I filed my 2019 return in March 2020, but have not received a stimulus payment yet.
Comment: You say that your parent didn't claim you in 2019, but what matters is whether someone *could* claim you. If someone *could* claim you as a dependent (i.e. met the conditions in the law for you to be considered their dependent), then you don't qualify for the stimulus payment (they would know because you would have had to check the box "someone could claim: you as a dependent" on your 1040), even if nobody actually claimed you. So could someone claim you as a dependent in 2019?
Answer: Assuming that you are a U.S. citizen or resident alien, then yes, you should be eligible for the stimulus check, or Economic Impact Payment, as it is officially called.  You have filed your 2019 return and are not a dependent, and are well under the income limits necessary for the payment.
The IRS has a page called Get My Payment, where you enter your Social Security number, birthday, and address, and it will tell you the status of your payment.  The tool may tell you that it has already been paid with details on where the money was sent, or it may tell you that it needs more information from you before a payment can be made.
If, for some reason, you end up ultimately not receiving the payment that you were eligible for, you will get a tax credit equal to the payment you should have gotten when you do your 2020 tax return next year (assuming you are still eligible in 2020).
Comment: "If, for some reason, you end up ultimately not receiving the payment that you were eligible for, you will get a tax credit equal to the payment you should have gotten when you do your 2020 tax return next year." That's assuming their tax situation for the 2020 tax year still qualifies for the stimulus (and still qualifies for the same amount).
Answer: It depends on whether they made the determination of your stimulus "check" (advance payment) eligibility and amount based on your 2018 tax year or 2019 tax year. If your 2019 tax return had not been processed at the time they made the determination, they would have used your 2018 tax year, and determined that you did not qualify. In that case, you would not receive the stimulus check, even if you later filed your 2019 tax return and you qualify under the 2019 tax year. See Question B9 here:

Q B9. If the IRS used my 2018 tax return and determined that I am not
eligible for a payment, and I later file my 2019 tax return that
changes my eligibility, will the IRS issue a payment in 2020 based on
the 2019 tax return? (updated September 24, 2020)
A9. No. If the IRS determined that you were ineligible for a payment
based on your 2018 tax return prior to your filing a 2019 return, the
IRS will not issue you a payment in 2020. If you meet the eligibility
requirements based on your tax information in 2020, you may claim a
credit in 2021 when you file your 2020 federal income tax return.

It's unclear whether your 2019 tax filing in March 2020 would have made it in soon enough for them to have processed it before they made the determination on eligibility for the stimulus check.
Comment: +1.  That is very interesting point.  It is unfortunate that the IRS might use the 2018 status, and they might use the 2019 status, and you really can't tell which one they will use.  Hopefully when the OP uses the [Get My Payment tool](https://www.irs.gov/coronavirus/get-my-payment) the results will shed some light on what happened.
Comment: Note that either way, the actual calculation will be based on all our 2020 filings. So if OP didn't get the check this time around, assuming the 2020 income is still in the limits, then they will be getting a credit when they file this year's taxes in early 2021.
Comment: @R.Hamilton: But the other way around is not true. If they qualified under the 2019 tax year, and got a stimulus check based on that, and they don't qualify under the 2020 tax year, they don't have to pay anything back, so they permanently keep the money. But if they didn't get the stimulus check in the same situation, and they don't qualify under the 2020 tax year, then they don't get the money. So it is much better to get the check under the 2019 tax year, for which the OP knows they qualify, than risk the uncertainty of whether they will qualify for 2020 (which hasn't ended yet).


Can I delete the folder "C:\WINDOWS\Installer\$PatchCache$"?

Question: This folder is taking up nearly a GB of my C partition. Is it possible to just delete it?
Answer: Heath Stewart's The Patch Cache and Freeing Space on MSDN blogs explains in detail. An excerpt:

[..] cause the Windows Installer service to cache any of the original files being replaced into the baseline cache. [..] It is this baseline cache that consumes a lot of drive space on the system drive after installing [..] The baseline cache facilitates patch uninstall by storing the original files so that they can be copied back to the target locations.
[..] by removing the baseline cache for a product, future repair, patch install, and patch uninstall scenarios may require your original installation media. If you have the drive space it is recommended that you keep the baseline caches available.
Comment: Note that he mentions that you should only remove **some** sub-folders from `$PatchCache$\Managed\ `. For me I removed MS Office folders as they were taking a lot of space and I have DVD for them. You should be able to easily recognize MS Office folders as they have files with MS Office icon in there.
Comment: Heath also explicitly said in a comment to his post that "you can delete %windir%\installer\$patchcache$. This may cause you to get source prompts for binary delta patches as well as during patch uninstall, but is otherwise okay. You must not delete any files directly under %windir%\installer, though. This will prevent you from repairing, patching, or even uninstalling products that use those files no matter what the type."
Comment: thanks for this - I moved the whole folder off onto a memory stick and rebooted and all was well. Saved me over 2GB (Win 7 x64)
Answer: I think it should be safe to remove the files, provided you're able to download them again in future if they're needed or if you have access to your original install disks. I had something similar on my computer, I just deleted it and install things from the original disk every time it asks me now. Inconvenient, yeah; but I don't often install stuff and it's a lot better than having a whole ton of space on my hard drive wasted.
Comment: It's recommended at least *to compress* `C:\WINDOWS\Installer\$PatchCache$` or the full `C:\WINDOWS\Installer` folder. The simple step can save really much space on the disk. There are exist many msp files which are not use cab inside. Such msp files can be good compressed and one get some disk space for free.
Comment: I'll try to move  it and see what happens
Comment: Reading the command line options for `msizap`, I wonder if *manually* deleting these files is indeed safe. Like for `msizap *` Microsoft writes: *Removes all Windows Installer folders and registry keys, adjusts shared DLL counts, and stops Windows Installer service. Also removes the In-Progress key and rollback information.* Does Windows also do this when manually deleting the files? (Do not run `msizap` without understanding what it does; see comments at [Joshua's answer](http://superuser.com/questions/82578/can-i-delete-the-folder-c-windows-installer-patchcache/137988#137988).)
Comment: @mechanarchy you may want to disable "Hide Protected System Files" from Options and then check.
Comment: Yeah, C:\WINDOWS\Installer\$PatchCache$ on my hard drive is empty, so I guess if it's safe for me it should be safe enough for you.
Answer: You could also try the MSIZAP utility from Microsoft. It has a "safe" option, 'G'.
Comment: *"MSIZAP and MSICUU2 are no longer supported because they have been found to cause problems. Please use the Program Install and Uninstall troubleshooter available here: http://support.microsoft.com/kb/2438651"* -- [11/22/2011, Jeff Ingalls MSFT](http://msdn.microsoft.com/en-us/library/aa370523%28VS.85%29.aspx?ppud=4)
Comment: Nice. But according to the article [mentioned by Scandalon](http://superuser.com/questions/82578/can-i-delete-the-folder-c-windows-installer-patchcache/217457#217457): *Take care when using msizap, though. "G!" is safe, but exploring other switches without understanding their ramifications could mean you cannot patch products anymore because product registration is missing (essentially making it appear to Windows Installer that your product is not there). Treat this like editing the registry.*
Comment: @mattwilkie You may want to include that as an answer too.
Comment: I tried running this on Win7 (my folder's 9.2GB) and saw no reduction in disk usage.  Is `msizap` still needed with Win7?
Comment: @DrewNoakes if you used the "safe" option, then I am going to guess that those files were all considered necessary.
Comment: @mattwilkie that link is dead
Comment: @novaterata https://support.microsoft.com/en-us/help/17588/fix-problems-that-block-programs-from-being-installed-or-removed appears to be working.
Comment: JoshuaDrake thanks! Nobody does dead links like MSFT. @mattwilkie how do you replicate the behavior of MSIZAP /G with this tool?
Answer: What I do for this folder is revisit it every now and then and only delete packages in there that are at least six months old.  This way, if there's a bad patch that I need to roll back, I can usually still do it.
Answer: If in doubt, you can always go safer way: simply compress entire Installer map! Right click on the Installer map (or just $PatchCache$ map) and choose Properties. On General tab, click Advanced button. Finally, check Compress folders to save disk space. If asked, choose an option to compress all subfolders and files.
This way you can gain up to 30% of free space (or in your case, nearly 300MB), and you keep everything in case you'll need this stuff later on. And system speed and response wont be affected much since system rarely accesses this map.
You can apply this tactic to several other non-essential system maps, thus recovering lots of free space on your drive!
Answer: Is it possible? Yes.
Should you? Probably not, if you don't have to.  Windows Installer keeps those files around because it think they're needed if you ever have to install another patch on top of them (or uninstall those particular patches).
Answer: Instead use MKLINK to junction the folder to an alternate drive if you have space
•   on drive D: create sub folder named C
•   cut and paste folder Installer to subfolder C-Windows located on drive D:
•   run CMD
•   type: CD C:\Windows
•   type: MKLINK /J Installer D:\C-Windows\Installer
•   type: EXIT
Answer: You can delete the folder content.
Follow these steps:
1) Stop Windows Installer the service.
2) Set the registry key that indicates the maximum folder size to zero.
3) Delete folder content.
4) Start Windows Installer the service.
5) Stop Windows Installer the service.
6) Set the registry key that indicates the maximum folder size to 10 (default).
7) Start Windows Installer the service.
Example:
Net Stop msiserver /Y

Reg Add HKLM\Software\Policies\Microsoft\Windows\Installer /v MaxPatchCacheSize /t REG_DWORD /d 0 /f

RmDir /q /s %WINDIR%\Installer\$PatchCache$

Net Start msiserver /Y

Net Stop msiserver /Y

Reg Add HKLM\Software\Policies\Microsoft\Windows\Installer /v MaxPatchCacheSize /t REG_DWORD /d 10 /f

Net Start msiserver /Y

Extracted from:
http://www.sysadmit.com/2016/02/GPO-Reducir-tamano-C-Windows-Installer.html
Answer: The solution is to use the command from Start → Run → cmd:
rmdir /q /s "C:\WINDOWS\Installer\$PatchCache$"

Warning: This will not affect the Installer folder. All content msi files created there will remain until the program is uninstalled. $PatchCache$ can grow up to GB of size which takes a lot of my hard disk space.
This command will delete $PatchCache$, and after you finish, run
dir C:\WINDOWS\Installer\$PatchCache$

… to see if the folder is still there.
You can also use
del /q /s %tmp%

which deletes all files in the temporary folder, which are created by installing software.
Comment: I assume the user knows how to delete the files in a folder. The question is whether it's safe to do so.
Comment: IMHO your answer is irritating, since it does not address the original concern whether it is safe, but instead provides a details "step-by-step" intro that suggest that it's totally safe to do everything you write - this is misleading and may cause potential readers a headache in the future.


Can I use unused pine bedding as mulch in my potted outdoor plants?

Question: My hamster recently died and I have lots of pine bedding left over. Is it possible to use unused pine bedding as mulch for the potted plants in my garden?
Answer: Yes, it's possible. They won't really improve the soil for a long time though (they'll take some time to break down), but they should conserve moisture well in a good layer, and keep the soil temperature more even.
I'd say this would be better for use on beds than in pots, you don't generally have to mulch in containers. But it won't kill anything, and might even help when it's really hot and dry out.
Answer: No, I wouldn't recommend it either. It will serve no real useful purpose, and will steal available nitrogen in the process of rotting down - if they are fine pine shavings, they may not remain in place and blow about anyway. If you want to top your pots off with something, use decorative pebbles or grit, but they don't really need anything on the top. You could, though, spread it out and turn it into the soil in empty ground, adding nitrogen if you want to plant the area, or better yet, find someone else who may be able to use it for the originally intended purpose, i.e.,  animal bedding. Alternatively, compost it with nitrogen rich materials.
Answer: Yes! We regularly use hamster pine wood chips as fertilizer, mixed in with topsoil and shredded dry leaves, and some cork, but only outside. It works great around azalea.
Answer: No.  Undecomposed wood will rob the plants of Nitrogen and do nothing for the soil until the wood is completely decomposed.  Then the mulch will add to your soil by feeding beneficial bacteria and organisms.  Plants in a pot are TOTALLY dependent on what you give them and no expense spared. Even in my outdoor gardens I ONLY use decomposed organic matter as mulch.  The only difference between 'good' soil and 'bad' soil is the amount of decomposed organic matter.  Don't need to manually mix decomposed organic matter or mulch into the soil as the micro and macro-organisms will come up, feed (and they can only eat decomposed organic matter!)and then go back into your soil profile, poop it out and THEY do all the mixing for you...IF you put decomposed organic matter on top of the soil!  Bark, raw wood, pine needles that are not decomposed will take time and the decomposers use lots of Nitrogen to do their work.  Fine for large beds, gardens that already have lots of organic matter in the soil.
Make double sure you have used a good potting soil.  Using garden soil in pots is a HUGE no-no.  It needs to start out as sterilized.  Lots of brands are finally putting bacteria and good fungus back into their soils after they've been sterilized. Try to find that on the labels.  'Doctor Earth' is but one brand that does this...
And make sure your pots have drainage holes, space between the bottom of the pot and whatever surface it sits upon and do not use anything except good potting soil in your pot. Do not use any gravel or rocks on the bottom under the soil.  This will cause the soil to become saturated before the water will drain.
Comment: I find the excitement over adding some garden soil to indoor plants is overdone.  A little clay will hold more nutrients and not break down as fast as a peat based mix. It's worked well for me.
Comment: If you know anything about plants and soils, you would never use garden soil for potted plants.  You've been lucky, I guess.  Plants in pots are totally dependent on what little they get from you and to put garden soil with not only beneficials but with disease, fungus and non-beneficial insects into a pot is just plain crazy.
Comment: J.Musser...you are correct.  Decomposers are everywhere all of the time.  We don't need to be 'feeding' them...I was of course talking about everything else in the soil that goes dormant if there is no decomposed organic matter to eat.
Comment: @stormy It's the *un*decomposed organic matter that they're eating.
Comment: Decomposers "eat" un-decomposed organic matter...no matter the conditions within our 'thin blue line' there are decomposers.  There is a multitude of beneficial bacteria, fungi and other organisms/insects that will either go dormant or move where they can find food, better environmental conditions when supply of food for # of organisms present is out of balance...too low. They'll come back after the decomposers make enough sustenance to support a thriving community plants need in their soil. Why wait years to feed these organisms.  Plants will suffer...they won't be healthy.
Answer: Yes! We have had only great luck using bales of pine shavings around flowering bushes and flowers. The pine shavings are cheap. We mix in some dried leaves, and come spring it had decomposed enough and enriched the soil. Go for it please.
Answer: Having had a small forestry block with pines, I wouldn't recommend it.  All vegetation around the pines dies.  This is for radiata pine, common pine grown for timber.  It is not because of the shade.  I have always assumed its a defense mechanism from the pines.


How to automatically generate indexes and preaggregations from queries

Question: This question might be a little ill-specified, but the idea I want to explore is:

User writes a bunch of queries that they want to perform over some data (for concreteness, just consider it a read-only database table)
The schema for the data is specified

Using this input, what data structures need to be generated to "efficiently" query the table? The program would read the input data and then generate a bunch of indexess/pre-aggregations so that the queries will be ultra fast.
For a really simple example, say I have a table of logs:
(URL, IP address, user agent, response code)

And I input a queries like:
select * where URL = http://foo

Then it should know to automatically generate an index on the URL field.
If I also specify:
select count(*) from table group by IP_address desc limit 20

or however you specify the 20 most common IP addresses, then it should also generate some pre-aggregation that is efficient (think of having 100 million rows).
I'm sure I am not specifying the problem completely, but I found some papers that seem related, i.e. http://scholar.google.com/scholar?cluster=1230153639822613926&hl=en&as_sdt=0,5
Looking for more references in this area. This is a computer science/algorithm question; I'm not looking for ways implement to implement this with MySQL or anything like that. Thanks.
Answer: Hmm...
You could use undirected multigraphs or alternative graph structures stacks (epicly space inefficient).
Comment: Multigraphs are not data structures.


Is there any other studio that is known for a quirk like how Shaft has its famous head tilt?

Question: I think another example of a quirk could be when an anime sometimes has the same thing or idea appearing in many of its series that the studio has produced.
Comment: You could try narrowing down the list, but it's only going to get you very limited or no answers at all. Indeed, forums or comment-based message boards are a better place for these kinds of questions.
Comment: Is it possible to have a clearer scope for this question? I am interested, but I do think you are right. This is probably better on reddit or a forum.
Comment: We're gonna end up with a million items in a list of all quirks and it's not allowed on this site.
Answer: One example is Studio Gainax, who are famous for their 'Gainax Ending', which original stems from the Ending of the Neon Genesis Evangellion series.

An ending that doesn't make any sense, or does make sense but is hidden under enough Mind Screw to not have an easy explanation. This is usually a deliberate form of Mind Screw or intended as a Sequel Hook to a sequel that was never made. For whatever reason, after watching a Gainax Ending, you won't have any idea what happened.
After rewatching it, rewatching the entire series, discussing it with other fans, looking up the meaning of the symbolism, and subjecting the entire thing to a comprehensive literary analysis, you still might not have any idea what happened. If you're lucky, then there will be some kind of emotional or symbolic resolution even if it doesn't actually explain what happened to the characters, and you'll be left with the sense that the series as a whole was more deeply thought out than it seemed before.
If you're unlucky, then you'll be left with more questions than when you started and the sense that the series as a whole has been voided of the meaning you once read in it.

You can see this in Royal Space Force: The Wings of Honnêamise, He Is My Master, Monchromatic, and many other series made by Gainax.
More recently however, Kill la Kill (by Studio Trigger - where many of the employees are ex-Gainax ones) has one of the protaganists hoping that "Gainax doesn't screw up the ending"
Comment: There's also a [Gainax Bounce](http://tvtropes.org/pmwiki/pmwiki.php/Main/Gainaxing).


Caterpillar(?) in Leaf Cocoon identification - Missouri

Question: A small chunk of leaves fell off of a potted tomato plant. We noticed our cats taking an interest in it once it started moving. Then a little caterpillar poked its head out. What kind of bug is this and should we worry about our plant?
Comment: Can you describe its size or take a photo with something for scale?
Comment: Larvae making these sort of cases out of found material is typical for Bagworm Moths (Psychidae), but I don't know what species you have in Missouri. But it's a start if you don't get an answer here.
Comment: I apologize, the bug moved shortly after I took the picture and now I can't find it. It was pretty small. The pictures above probably show about 1cm of its body poking out and the diameter of the bug is less than half a cm, I would say.
Answer: This is the larvae (caterpillar) of a bagworm moth (family Psychidae).

 Source: Wikimedia Commons; Credit: Bernard DUPONT
From Wikipedia:

The caterpillar larvae of the Psychidae construct cases out of silk and environmental materials such as sand, soil, lichen, or plant materials.

There are about 240 genera, so I will leave IDing to lower taxonomic levels up to you. However, based on the striations of the caterpillar and your lcoation, the Evergreen Bagworm Moth doesn't seem like a bad guess...


Is there a module that will add an image field that displays an image from an off site source?

Question: Im on d7. I'm looking for a way to have images displayed on my site from another image hosting site such as imgur or imageshack. Right now I've been using the media module for uploading images to my site and it works great, but I don't want to store the image on my server. I need the ability to "source" where the image came from, but the media module doesn't store that info, it just downloads the file. thanks for your suggestions.
Comment: this question might help: http://drupal.stackexchange.com/questions/20595/fetch-images-across-the-internet-with-file-api
Answer: You should take a look at the remote stream wrapper module and this issue that explains how to do it.
Answer: Unless Media Flickr does exactly that, I don't think what you ask for is available to this point.
The best suggestion I have, is to write a module that extends media, to do what you want. I've been involved in a project to integrate media with a media bureau's photo repository, so I know that it can be done. Unfortunately, there is no code from that project I can point you to at this point. The media flickr module may be a good source of inspiration though. This is the best solution because once understood, will require little work to extend to a second service, and it can be contributed back to the community. The problem here is that media seems to be a moving target at this time.
The second best suggestion, is to wrap an imagefield with a custom widget (for node edits) and a custom formatter (for node views) that does what you want. This will unfortunately become a specific re-implementation of media, and as such, not a general solution.
Comment: Thanks for your suggestions. Im thinking I may be able to achieve this by making a common textfield for users to paste a url to an image into, then on a node page wrap the "value" of the field in an [theme_image_style()](http://api.drupal.org/api/drupal/modules--image--image.module/function/theme_image_style/7)
Comment: Never mind about the theme_image_style(), doesn't work for outside images. Hmmmmm....


Are "advantages/disadvantages" questions on topic?

Question: For example questions like this that ask about if feature/algorithm X has an advantages/disadvantages over feature/algorithm y. Such questions encourage discussions and some of the questions and answers might be subjective. Should we consider them on topic or now?
Answer: Advantages and disadvantages are rarely very cut-and-dry, and as such tend to have some subjectivity to them. They seem to me to be highly-related to questions where the answer is "it depends," which we don't have a clear community view of.
So I would say that unless the advantages and disadvantages list is very broad, then these questions are generally subject to the "good subject/bad subjective" barometer.
Answer: In my opinion such questions are not subjective when the topic in question has a proved advantages or disadvantages. For example it is mathmatically proved that A* has an advantages over Dijkstra. On the other hand, such questions might become subjective were topic X doesn't have proved advantages/disadvantages and it becomes subjective to the observer interpretations. One example could be "What are advantages of Quick time events cut-scenes over playback only cut-scenes"1.
1 I just made this question up
Answer: I don't think you can ask an advantages / disadvantages question without it boiling down to a "Which tech to use" question (unless you are very crafty). These kind of questions are very situational and don't offer much useful insight to future visitors. They don't solve a problem.
Instead of focusing on general queries like what are the pros & cons of X, the question should simply be how could I get Y done, I used X so far and result are unsatisfactory because...
I think the rule of thumb is that if that once the question is answered, you should have your pragmatic goal accomplished and make real progress. Questions about pros and cons aren't going to help you complete any tangible tasks.
I remember asking questions like this once about Haxe and also about different ways of implementing the Events pattern. Reading the answers was an enjoyable experience but they were obviously not gong to help me make any actual progress. I still had to play around with Haxe and decide if I like it or not. I also never really had a problem with the Observer Pattern. I wanted to learn about alternatives implementations out of curiosity. The answer was informative and well written; I suspect it was not really useful to anyone in a bind.
I think SE really shines when it helps people who are in a bind and we shouldn't let people crowd with questions that are simply there for fascination and enjoyment although it sounds dreary, it helps keep SE lean and effective.


Is a cannondale scalpel 3 full suspension capable of trail/ downhill? (100mm Suspension)

Question: I have found myself to be more of a trail rider than an XC rider and would like to get into downhill. I have a cannondale scalpel 3 and I was wondering if I can make this bike work. Possibly buying the new 130mm lefty supermax or other mods. Or just trade in for a new bike.
Comment: [The 25th Infantry](http://watch.montanapbs.org/video/1499356776/) rode from Missoula Montana to St Louis Missouri on bicycles made of wood.  In 1897.  They did pretty well with no suspension at all.  (The big innovation was metal wheels, instead of wood.)
Comment: I don't think you could put a longer travel fork on the Scalpel, it's built as a lite xc racer so may not handle the stress. I think if you are finding the headtube angle too steep and wanted something slacker (especially downhill) you'd be best trading in for a Jekyll which is built for the longer travel lefty, or leave cannondale altogether. Otherwise if you don't find the bike bad to ride the components will stand up to pretty much everything you throw at it (apart from pure DH) but you'll get more enjoyment out of something slacker.
Answer: A lot depends on what you mean by "trail/downhill" and by "work".
It wasn't that long ago that a full squish 100mm fork bike was a full on downhill machine. However, the big drawback to that bike as a descender is the relatively steep head angles.
Putting a bigger fork will help with that, but it won't help with the issue of how robust the parts are relative to the use. Lefty forks are meant for XC lightweight
applications, not for landing 10 ft drops. Putting a slightly longer and more robust fork on that bike will help a lot with feeling in control on descents, but it's still an XC bike and has limitations in how hard you can ride it.
It all depends how rugged your trails are and how hard you intend to ride.  If you still want a mostly XC bike that handles descents more effortlessly then a fork upgrade makes sense. However, if you're looking to go beyond that then you really should consider getting a different bike.
Having said all that, outside of a terrain park, I don't think there are many trails that couldn't be descended with that bike. It's just a question of how fast, how much fun and how much skill is required.
Comment: I agree with most of this (I was writing my comment at the same time you were preparing this novel!) apart from being able to fit a long travel fork on. I think the force would be too great and could lead to a failure at the head tube/ down tube weld. But agree essentially this bike would handle most trail riding.
Comment: It's probably not manufacturer recommended, but I've had no problems running forks as long as 140mm on 100mm XC bikes. But I also don't push my bikes that hard.


Are there any cyclocross/road bike rims that I could buy that will fit on my Cannondale F600 mountain bike?

Question: I want to be able to ride my mountain bike on roads, but the sound of the mountain tires on the road is annoying. Can I just buy rims that will fit cyclocross or road bike tires? My bike has disk brakes.
Answer: Do you mean rims or wheels?
Many cyclists have a second set of wheels for their bike, because it's a lot cheaper than having a second bike. Buying a set of 26" disk brake wheels with narrow rims and putting slicks on them is a pretty common thing for MTB owners who commute on their bike. You might also choose a slightly higher-geared cassette for the road wheels. You will need a second cassette on the new wheel, and a second pair of disk rotors. Two complete wheels, in other words.
If you are talking about rebuilding your wheels with narrower rims that's expensive and I think pointless - it will not be much cheaper than getting a second set of wheels, and will limit your choice of offroad tyres. You can mount fairly narrow tyres on most MTB rims, especially on newer bikes as there's been a fair bit of work on making fat tyres work on narrow rims, so racing cyclists can have narrower rims (because they're lighter).
The cheapest option is to just buy skinny tyres, but that means swapping tyres every time you want to go off road. Which is why many riders buy extra wheels. Another cheap way is to get a second hand road bike (but be aware that that is a slippery slope and many of us have more than two bikes)
Comment: Be careful here.  You need to get special wheels that accept disk breaks.  Normal wheels will not handle the forces of breaking.  I defiantly recommend getting a second set of wheels however.  I have second set for my mountain when I want to do road riding on my mountain bike.  I also have a pair of chubbier tires for my road bike (for carrying heavy loads and doing dirt roads).
Comment: @sixtyfootersdude: have you seen really disk compatible wheels sold that are not up to the task? I haven't, but I don't really trawl the extremely cheap end of the market. In my experience anything with disk hubs is built to take the forces.
Answer: It looks like the Cannondale F600 mountain bike has the typical 26" mountain bike tires.  It's very unlikely that the larger diameter ("700c") rims used on typical cyclocross or road bikes would work well.  There are road bikes with 26" rims, typically made for shorter people (especially women and children), so it would be possible to find rims in that size (but would make more sense to simply buy new wheels than to build wheels with new rims).
However, you can buy smaller, thinner, smoother, higher pressure tires for a 26" rim, and that would solve your problem quite handily.  It would also be much cheaper ($20-$50 per tire) than replacing the rims (or whole wheels).
Comment: @M. Werner: as long as he keeps the same disk rotors he won't have a problem with the brakes.
Comment: Exactly.  The big problem is the brakes; they simply won't line up with the larger-diameter wheel, and there may be problems physically fitting such a wheel into the frame.
You can buy excellent "street tires in 26" size these days, and they will make road riding noticeably smoother and more efficient.
Comment: Thanks! I bought some thinner tires with less tread and they make much less noise.
Answer: If your bike takes 26" wheels, then road/CX wheels won't fit, they're too big. There's also the width of the rear hub; on most mountain bikes it's 135 mm, on road bikes it's 130.
Just get some skinny 26" tires, most shops will have them.


Are the submarine cables used only for internet?

Question: We can see that almost all of the servers are interconnected between each others using submarine cables which ends in a complete hierarchy but question is are those internet connected cables are used only for connecting internet servers between each others ?
Answer: It depends what you define as the "Internet", If by the "Internet" you mean the large mesh of publically routable IP space then no. These cables can also be used to provide direct private optical waves between two endpoints, similar to a very long point-to-point Dark Fibre.
When these wavelengths are sold to providers it is then up to the provider to determine how they wish to use this service. If they want to run their International IP backhaul over it then so be it. From the Cable manufacturers point of view, they're purely selling a Layer 1 service.
Comment: Telephone, fax, video conferencing, text messaging, it doesn't really matter as they can all be translated to some protocol that flows on top of IP. A lot of it would be UDP actually. But as people have said before, you rent a specific wavelength of light in a strand of fibre, then what you do with that wavelength is entirely up to you.
Comment: @Taher, Nope, if I wanted to run just point-to-point layer 2 service then I could.
Comment: so they are basically used only for TCP/IP connections ? am i right ?
Comment: yeah i understand but the final goal is to be able to use the TCP/IP connections ? i mean providers will not use them for phone telecommunications or other goal ?
Answer: No  this cable can carry different types of traffic other than internet traffic . Submarines cables are just physical connectivity from and to connecting two geographical locations . Further to i this cable bandwidth can be utilised for internet and point to point links for private leased lines connectivity this can be achieved  by creating vlans isolating traffic that passes through this Submarine cable using Vlans


Can rabbits remember from long ago

Question: I had an old bunny and one day it disappeared, we don't know if it ran off or if it was stolen. Today we were wondering if our old bunny might still remember its name if we ever saw it again.
Answer: Rabbits can remember things for years. We had a rabbit 'Harmony', who we adopted from the local shelter.  A couple of years later we took her to the shelter for an adopted pet gathering. Her behavior was very different then other places we have taken her.  She clearly remembered the place (she did not like it).
Sadly, the there is almost no chance your rabbit is alive. See our related question Can I release my pet rabbit in the wild? and this PDF at rabbit.org
Answer: I searched for a scientific reference, but there is not much specific about rabbits. Rats are well observed and tested, so maybe one can transfer some findings from them.
First: "name" against "sense"
Rabbits are able to learn their name. But this is not the direct way, they remember things. They identify rabbits/persons/things by its shape, sound and its smell. So I assume they would remember the shape, sound and smell of their owners for a longer time than the sound of their names.
Second: "active memory" against "association memory"
I assume rabbits have like other "elopement animals" (animals who run away to keep alive) a strong associating memory. There is not time to remember and reflect if you sit face to face to a predator! Horses are here well observed. They remember things (not only, but almost) just if they are confronted with same circumstances. They do not see in the future "if I led to the parking place there will be the hated transporter" or likewise. They remember the bad memory about last transport not until they stay at the same place as in this memory, and than act immediately (for example run away), to owners surprise.
So I came to the conclusion, the memory that will remain at last about its owner would be something like a ritual from formerly life, connected with shape/smell/sound of the owner.
How long this memory will remain, I can not assume. But I have read some stories about "owner recognition" after the period of one year.
Comment: Like I wrote in the first sentence: I had no luck to find some sources about rabbits. The knowledge about horses came from some books from Monty Roberts and Andrea Kutsch. The "learn their name" comes from this [Question from Reddit](https://www.reddit.com/r/Rabbits/comments/3jurfa/do_bunnies_respond_to_their_names/) and "smell, shape and sound" from the "rabbits for beginners" book from the pet shop

Can rabbits remember from long ago


How to display 1 full article and the a summary of others

Question: Hi I'm new to Drupal and I'm trying to find a way to display on my home page the full version of the latest article and a list of other articles as teasers.
The teasers could be either listed under the full article or in a block in the sidebar. Is this possible? Currently I can only list articles as teasers.
Comment: Check out views.  You can create a views block that shows the latest full article and then add an attachment that shows your teasers.  You would be able to put the block anywhere.
Answer: Install Views, then enable the disabled view called Front page.
To get two different view modes for the nodes, you could add an attachment display to the view that shows a single latest article in full view mode and add it to the view at the top. Then you would set the page display (the original view) to display teasers, starting at an offset of 1.
It could also be accomplished with Display Suite.
Answer: You can create two views block.
Create a views block for latest article like this way
  under Format, select content (full content) in show filed.
  select update date field in filter criteria.
  In Advanced Options,  under Pager ' Display a specified number of items' as 1

Create another views block for other article like this way
  under Format, select content (teaser) in show filed.
  select update date field in filter criteria.
  In Advanced Options,  under Pager 'your choice' and set offset value as 1

Now display the blocks where you want.


Help for Creating Web map application

Question: I would like to create a web application with map and I am wondering which platform to use. I don't have enough budgets to build my own GIS server infrastructure. As a base map I am going to use available WMS, and on top of it there will be points, lines and polygons. The problem is that I want to have full control over my GDB and to use time enabled data. Can you help me with some ideas?
Comment: Hi, welcome to GIS stackexchange.  To get the best sort of answers, you'll need to add a little more detail to your question.  Stuff like.. what are you going to be using this application for?
Comment: What do you mean by 'full control over my GDB'? Does your application need to sync/update data or is it a one time thing? Data won't remain in GDB, it will be converted to a format for delivering to the web. A most basic solution would be CartoDB, they have an easy time enabling solution called Torque.  But like Guy said, it all kind of depends on the details of your application.
Comment: Hello and thanks for your quick replies. I am planning to create a web application for a small region with information about attractions, hotels, etc. and main activities in the region. And I would like to visualize them on a web map. When I said to have a full control over GDB, I mean that I need to be able to make DB edits including multiple features edits.
Answer: There are lots of tools for making web map applications but each is suited to a particular use case. The real question is what skills you have and what tools your users require.
If you don't want to write/maintain any code and require a rich array of tools out of the box then you should checkout MangoMap. Here's an example of the type of maps that can be quickly produced without writing a lick of code:
https://mangomap.com/maps/28077/Lower%20Manhattan%20Commercial%20Space%20Analysis
https://mangomap.com/maps/25821/Bristol%20Property%20Finder#
Mango also has data editing tools so you can keep your data up to date from within the app or easily replace existing data by doing a simple upload.
Answer: I'd take a look at CartoDB, especially for the time enabled stuff. It's also possible (with a paid subscription) to hook your cartoDB account to google drive, or data in dropbox. It would at least be a start and you can build off of it with their APIs.

Help for Creating Web map application


Where shall we use an authenticated encryption mode?

Question: I learned from Wikipedia that authenticated encryption modes include OCB, CCM, EAX, GCM, and so on. Does this mean that when we want to use authenticated encryption we shall use these modes? But these modes don't use public-key encryption or a hash-based MAC, which may be more advanced. So when shall we use an authenticated encryption mode, and when shall we use other MACs such as HMAC-SHA-256?
Answer: OCB, CCM, EAX, and GCM, being modes of operation, only work with block ciphers. Some of them, like GCM, are only defined for block ciphers with a particular block size. Note that these authenticated block modes do use MACs (GCM for example is essentially CTR mode with GMAC). Other MACs like HMAC and Poly1305 work with any symmetric cipher, including stream ciphers. So for example if you wanted to use ChaCha20 or were stuck with AES in CBC mode, you could use HMAC-SHA-256 or Poly1305.
These modes all work differently, and in fact are not always even based on the same concept. The only similarity they have is that they can all be used to turn an unauthenticated symmetric cryptosystem into an authenticated one. Internally, each construct is different. GCM for example is an authenticated cipher mode of operation, HMAC is a keyed pseudorandom function, and Poly1305 is a universal hashing one-time MAC. They are quite different, but they all happen to be useful for authenticated encryption.
Although the specific modes you provided all provide effective authentication, they're not always suitable for use everywhere. They are each based on completely different concepts, and they can each be used for only specific purposes. Their only similarity is that they can all be used to authenticate a symmetric cipher. Here is a quick summary of the various modes and where you might use them:

OCB, an authenticated mode of operation for cryptographic block ciphers, is fast and lightweight, but is patented so might not be legally viable for everyone.
CCM, an authenticated mode of operation for cryptographic block ciphers, was written as a non-patented alternative to OCB for use in 802.11, but is very slow.
EAX, an authenticated mode of operation for cryptographic block ciphers, was written to address several criticisms of CCM mode, but is just as slow as it is.
GCM, an authenticated mode of operation for cryptographic block ciphers, is fast and widely supported in hardware, but can be vulnerable to side-channel attacks.
HMAC, a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret key, in ETM (Encrypt-Then-MAC) mode is easy to plug in to any cipher, but is not fast.
Poly1305, a universal hashing one-time MAC, is extremely fast and almost always a good choice. It's only recently gotten popular.

In general, you should not need to think about the specific authentication mode you use. You should be using a simple and friendly library that does all this for you, like NaCl (which I believe uses Poly1305).
Comment: Not really the fault of AES-GCM: exactly the same mistake _could_ have been made with ChaCha/Poly1305, but wasn't.  (The mistake was to let the sender choose the nonce arbitrarily, rather than requiring it to be the TLS record sequence number.)
Comment: I would strongly advise against writing a parallel sentence structure for very much non-parallel concepts.  For instance, GCM, HMAC, and Poly1305 are all different _types_ of concepts, and as such incommensurate: an authenticated cipher construction, a pseudorandom function family construction, and a specific universal hashing one-time MAC.  But putting them side by side in a table makes it seem like they are commensurate concepts.
Comment: @SqueamishOssifrage Alright, I'll make edits to explain that.
Comment: GCM/GHASH was first published at INDOCRYPT 2004, and Poly1305 at FSE 2005 about two months later.  While it may be technically true that Poly1305 is newer by two months, does that difference matter fifteen years later?
Comment: @SqueamishOssifrage Good point. While it really isn't that new, it's only recently been gaining traction.
Comment: While it is true that AES-GCM was formalized for TLS longer ago (RFC 5288 in 2008), the first version that wasn't screwed up about nonces didn't appear until TLS 1.3 last year—and vulnerabilities arising from that mistake were [deployed in the wild](https://eprint.iacr.org/2016/475), including at banks, credit card companies, and stock exchanges.  Poly1305 has been used in NaCl and anything downstream of it since 2009; it has been deployed in SSH since 2013; and unlike AES-GCM, ChaCha/Poly1305 was done right the first time around for TLS in RFC 7905 in 2015.
Comment: @SqueamishOssifrage Yeah, GCM is amazingly fragile. That's why I suggest using NaCl. :P
Answer: When you want to exchange messages with someone who shares a secret key with you, and you want to ensure that nobody else can forge or eavesdrop on the messages, you should use an authenticated cipher, like crypto_secretbox_xsalsa20poly1305 or AES-GCM.
You should forget that 'block ciphers' and 'modes of operation' exist.  Internally, any authenticated cipher will have some mechanism for authentication, and often in principle it can be separated out—e.g., crypto_secretbox_xsalsa20poly1305 uses Poly1305, and AES-GCM uses GHASH, which are both one-time MACs based on polynomial evaluation universal hashes.  But these are implementation details that don't need to concern you when you're just using an authenticated cipher.
If you need only prevent forgery, and not eavesdropping, then you can just use a MAC instead of an authenticated cipher.


Do I have to run an extra wire all the way to my new thermostat, or just to the "router"?

Question: I've got an older home (plaster walls) and an older furnace, It's a Peerless.  My current thermostat is located on my main floor and only has 2 wires to it, red and white.  I should mention that my heating system is hot water with radiators.  Anyway, I want to get a new wireless thermostat installed.  I'm pretty sure I will need a new thermostat wire with a C wire in it, but can I just install that straight from the furnace?  The "router" or base will be located in the furnace room so I'm not worried about having to snake it through the walls but I'm wondering if I have 24v coming from the furnace and if I can easily replace my current thermostat wire with a newer one with a dedicated C wire.
Comment: Do you have a link to any details on the specific thermostat you're considering?
Answer: Trace where the wires from the thermostat to your furnace. You'll find that one connects to a relay and the other connects to a terminal on a transformer. R is the wire from the transformer, W is the wire to the relay. (Your thermostat may be connected to the wire backwards, but that doesn't matter.)
Your new C wire will be the other terminal on the transformer. Or if the transformer has multiple taps/terminals, then it will likely be labeled COM or -.
I suggest instead of trying to monkey with the wire to your existing thermostat that you just investigate where it's connected to and make new connections. That way if you run in to problems you can simply reconnect the old thermostat easily.
Answer: The R wire (or wire wired into R at the thermostat) will be your 24v continuous power. If you want to use a thermostat with wireless capabilities you will need to run a new wire (at least 18/4 wire) to accommodate the new thermostat. Depending on the type of thermostat you get, you will either need to wire it to the furnace, or to an EIM (equipment interface module) and then to the furnace.
Another solution is to get a wireless communicating thermostat. These types of thermostats only require continuous 24v power, and a common to run. This may be taken from any source (such as a transformer in the furnace). Then you will have to install an EIM in the basement that communicates remotely with the thermostat. Then he EIM will be wired into the furnace and will activate certain operations from the unit.
This type of thermostat may be the easiest for your application, however there are very few of these on the market, and are quite costly thermostat packages.
Comment: Thanks Mnc123, and that's exactly what I want to try and do.  Set up an EIM in the furnace room, near furnace and have it communicate wirelessly to my thermostat, which I can place wherever I want.  So what you're saying is I can "add" a wire (18/4) to the "R" wire on my furnace and then put in on my new EIM, and then add the 2 wires that ran to my thermostat, with a total of 3 wires now to my EIM, that should work right?  I'm only looking to control heat as I have hot water heat with radiators.  Thanks.
Comment: Yes im aware that this is a heating only system. The only reason you would be adding this type of thermostat is to get Wi-fi capabilities. This includes being able to monitor and control the temperature of your home via a smart phone app. If you do not need this function, and just would like a newer style thermostat, i would recommend getting any standard thermostat that you prefer and only hook it up for heating. Now wiring between the thermostat and equipment interface module is dependent on the thermostat manufacturer and the specific thermostat.


can running just water ruin my water pump

Question: I have 2005 Jeep Liberty, the radiator had a pin hole for the last few months i have been keeping water in it, then I had the  radiator replaced yesterday and now i have another leak. I took the car back to my mechanic, and he told me that running just water has messed up the water pump. The water pump has never  leaked until after the radiator was replaced. Is it just me or dose this seem a bit fishy? i mean how dose it not leak one day and then all of sudden it starts after the radiator was replaced. I would just like to know if this is common or am i being scammed.
Answer: Yes.  Your water pump could easily have rusted out on you.
See the picture at the bottom of the answer in the duplicate question.


Password no longer works on MacBook Air Yosemite 10.10.2 I need to reset the password, without logging in

Question: I do not know why, but my password is no longer working on my MacBook Air v. 10.10.2 Yosemite. I have tried several things including restarting in Recovery Partition, going to terminal and typing "resetpassword." This does pull up the standard screen that allows me to change the password, but then the volume containing the user account never shows up, which means I can't select it to change the password. I have also tried the older method of deleting the /var/db/.applesetupdone file through terminal, but it seems this file doesn't exist for v.10.10.2. I've looked at the Installer Log, and some things I noticed are "keyboard layout identifier -16899 has been replaced with -28673" and other related messages, as well as "Can not connect to /var/run/systemkeychaincheck.socket: No such file or directory", and "Could not read prev-lang:kbd to set keyboard". I don't know if any of these messages are related to the problem.
Comment: A modified keyboard layout may explain why your password does not match. Some people on the interwebs suggest using an external keyboard to rule that problem out.
Answer: Note: I'm not able to test this so I don't know if a backup will reintroduce the same problem. Also note that this is more of a blunt instrument approach
Firstly, I can't speak directly to the terminal logs. Someone may have a more sublime approach using that information.
If you have a Time Machine backup, you can reinstall OS X following these instructions (from this page). Once a clean Yosemite install is ready, you can migrate your user settings and data using Time Machine.
Clean Install OS X Yosemite
It's time for a clean install. We're going to show you how to do it without using a USB drive, which makes it much easier and less confusing. So to start, you should download OS X Yosemite from the Mac App Store. Once it's finished downloading, it'll immediately load up on your screen. Follow the instructions to install OS X Yosemite. Once it's done, it'll ask you to restart your Mac. Do it, and once it's loaded up, we'll start the clean install process:

We're going to restart your Mac again. But this time, hold down Cmd+R. (Keep holding it down while it restarts, do not let go)
Now, your Mac should load a screen with a few options (you can let go of Cmd+R now).
Select the Disk Utility option.
In the window, at the top of the left bar, select your Mac's Main Drive. It should be something like MainHD.
Now, select the Erase tab, located next to the First Aid button at the top-center.
Near the center of the window, select the Format drop-down list and select "Mac OS X Extended (Journaled)" as the type.
Click Erase (this will erase your main drive!) and allow some time for the drive to format.
When it's finished, close out Disk Utility and select "ReInstall OS X" from the menu. It will ask for your Mac App Store password to redownload OS X Yosemite. Give it a minute to do so.
A new window should pop up and OS X Yosemite should begin to install. If it does not, press back and enter your password again.
Once again, follow the install instructions and enjoy your newly clean-installed OS X Yosemite.

At this point, you'd migrate your Time Machine backup, and fingers crossed, you will have cleared the password problem.
Comment: I was hoping for a less brut force way, one that solves the problem directly instead of just starting everything from scratch, but if it works, it works. I'll let you know wen i try this method. Thanks!
Comment: Understood, @luca590. I'm just not sure you'll be able to alter any file that is related to your admin-password without being able to authorise the change using said password. You _might_ be able to reinstall just the system from the recovery disk, however it may need your admin password (I'm assuming that's the one that's borked, not your user password). You can try that first. It will leave your user file and data alone.
Comment: I'll accept your answer because it does work (it also clears the hard drive, but I think the problem was that the password had been changed via iCloud, which is now linked to domestic account passwords on Yosemite.
Answer: I don't have an answer to this issue, just an observation.
I have observed this symptom on a number of freshly installed OS X 10.0.X systems.
On both occasions the systems worked fine until a restart was required after installing software from a package.  Both times the packages were simple printer drivers.
Both occasions occurred during a Mac Yosemite 10.10 Essentials training course.
On both occasions it was only possible to login in safe mode, verifying that the correct passwords were still known.  However the passwords would not work with a normal boot up.  Resetting the passwords did not work, except to say the new passwords were verified in safe mode.
Both occasions required a complete reinstall.
Signed.  Too scared to install from packages anymore!!!
You're safer with installs from the App Store!!!


When does the forest end?

Question: I've been on this quest for about 20 minutes and it doesn't seem to have an end. I have 150,000 candies so far from killing the wolves, trees, etc. Am I just impatient? Another thing to note is that my screen is flooded with Octopus warriors - do they need to be out of the way for me to progress?
Answer: You have too many octopi. They'll be preventing you from moving right. I'm afraid you'll have to abandon your progress and restart, maybe without the obsidian crown? I find it easy to get through the forest with the jasper crown and enchanted monkey staff.
As a general rule, in most levels, if you can't see the background scrolling, you're not moving and the level won't progress. This is particularly relevant in the sea, where if you wedge yourself against the ground the waves of fish won't end.
Comment: The Black Magic Grimoire lets you cast Black Demons. The demons will kill some of the octopi, but they might also hurt you. Useful if you don't want to lose your progress and are willing to lose some health to finish the level.
Comment: I was able to use Jump (from the pogostick found in the mountains) to jump over the octi and reach the end
Answer: yes your octopus warriors will stop you from walking forward, so youve been standing in place this whole time. either teleport out or start over. generally the obsidian crown is more burdemsome than useful
Answer: Teleport yourself in order to past through the Octopus. Jump over them when you reach any of them.
Answer: The Octopus warriors block your further advance to the right of the screen.
Answer: Another solution is to jump over them. I've just tested it, and you can't squeeze past them, however, jumping seems to work just fine (may need desert bird's feather).
Answer: Check to make sure you are not wearing the boots of introspection. these will make is so you can not move at all. Though they look helpful, they really don't particularly help in combat.

When does the forest end?


How can I revive a Meyer Lemon Tree with no leaves?

Question: Here is what my Meyer Lemon Tree looks like:

No leaves anymore. Is there a chance that it will ever revive itself?
Answer: The hope seems pretty small, especially if it's been like this for any length of time.
No leaves, sitting in a saucer-full of water.
Either it's been soddened to death or it was parched to death and the soddening is a belated attempt to compensate. In either case sodden is not good for anything that doesn't normally live in a bog. Moist is about as much as you want, especially when there are no leaves on the tree.
Edit - there's definitely more hope for it if you weren't the person who killed it; thanks for making that clear. If there's green there's the hope of a latent bud waking up and putting out a new leaf, and all that follows from that...
Comment: If you have some green and you keep it moist, it may yet make Zombie Lemons ™
Comment: It was just given to me so I do not know what killed it. I did prune some of the dead branches that had super dry leaves.
Answer: Scrape back the skin of the bark with your fingernail - do it near the base of the plant. If what's beneath is dry and brown, its dead - if there's any green or moisture, then it might recover - though not if you leave it sitting in water.
UPDATED ANSWER:
You've said it seems green inside and you've removed it from the standing water. It needs warm temperatures and sunlight, but it will not like being sited in a window which has a radiator or heat source directly beneath - I can't tell if there is one. Water only when the surface of the compost feels just dry to the touch, but not so dry its shrunken from the sides of the pot. When you do water, water well, but empty out that tray after 30 minutes, and again 30 minutes later if more excess water has collected.
Comment: It is still green. It is not sitting in water anymore. Thanks for the tip!
Comment: @Asimov4 see updated answer...
Answer: Looks like you're in northern hemisphere, so you'll be heading to summer.
Three things to consider...
Citrus trees are tough but as others have mentioned, cannot survive wet roots and require extremely good drainage.
Citrus trees, in their natural state, feed from their drip line. This means that the tree's feeder roots will be in line with the outside edge of the tree's branches. Your tree is young so I'd not concern yourself too much with this, but it is an important consideration as the tree grows. What I'd suggest is that you consider moving the tree to a pot with a larger diameter - if possible. This will also allow you to ensure the soil medium is improved and provides the extremely good drainage necessary.
Finally, in the southern hemisphere, citrus trees put out their annual burst of new growth in Autumn. I cannot imagine this would be different in the northern hemisphere. So, if you can keep your tree alive until autumn, there is every chance the new growth will shoot then.
I'll repeat the comments by others... allow the soil to dry between watering. Do not allow to become "bone dry", but so the top inch of soil is dry and below that moisture is scarce.
If you're interested you could by a soil moisture meter to help you with the watering decision. Old style analogue meters are relatively inexpensive.
Answer: Yes, there's definitely a chance that it will revive itself, but at that size, I'm thinking something must have caused the leaves to fall off, and if it wasn't underwatering (which seems to contribute heavily to leaves falling off, although it appears to have more than enough at present), then the issue may still be present. If your window is cold or if you've got a fan in the room (which would dry the leaves), that might be contributing to the leaves falling off. Improper soil amendments may also be an issue. My grapefruit tree really didn't like basalt rockdust, for instance (none of our houseplants did, although some outdoor garden plants, such as cantaloupes, seem to love it).
If it was under-watered before the leaves were gone, or if it didn't have enough light, then I'm sure the leaves will grow back now that it has water and a window, as long as it's still alive. It's possible that you have too much water in there, now, though (especially as there are no leaves), but if your waterings haven't been frequent, I wouldn't worry about the excess over-much (maybe drain most/all of it out if the plant doesn't absorb it all within a day or two of when it was first given).
I have experience with a grapefruit tree (it's 20-something years old), but I've never grown a lemon tree. It sheds its leaves sometimes (usually if it doesn't have enough light or water). Mine uses any excess water I give it within a day or so, but I don't have to water it terribly often, and it's not in the most humid area. Although the leaves usually grow back pretty fast once conditions are corrected, I believe they were gone for maybe two weeks or more, once (but the conditions may not have been corrected quickly). It was probably at least a couple feet tall (grown from seed) before it ever lost all its leaves.
Answer: The over watering and wet roots is an issue . When the leaves return use a spray containing macro nutrients on the leaves. Spray heavily and especially the bottom of the leave where the stomates are . Spray during the day when the stomates are open
Answer: It would have a better chance if you could put it outdoors in some sunny location.


Can I use a fixed IV with AES-GCM if I only encrypt unique plaintext values?

Question: My use case guarantees that all plaintext values are unique. In this case, is it safe to use a fixed IV with AES-GCM to carry our encryption/decryption?
Comment: @Mikero, indeed, I read that answer already, I just wasn't sure if the messages being unique make a difference.
Answer: No, when an IV is repeated as in $C_1 = \textsf{GCM}(K,IV,M_1)$ and $C_2 = \textsf{GCM}(K,IV,M_2)$, the resulting ciphertexts leak $M_1 \oplus M_2$ to an eavesdropper. This is because GCM is based on CTR mode which has this property.
Authenticity also completely breaks in this scenario, although it's not a one-liner explanation.  An attacker who sees $M_1, M_2, C_1, C_2$ can forge arbitrary ciphertexts.


How could Pablo Escobar earn so much money?

Question: I read it's about 30 billion. But I read there were 6 million users in 1985. Let's say he gets 10 percent of the sales price, it means each person paid 50000 dollars for cocaine. It sounds way too much. Any calculations how they reached this amount?
Comment: In 1989, *Forbes* magazine estimated that his wealth was "only" \$3B ([source](http://articles.latimes.com/1989-07-10/business/fi-2595_1_richest-people)). Adjusting for inflation, that might be \$5B or \$6B in today's dollars, but nowhere near \$30B. Escobar's son disputes even the \$3B figure, calling Forbes liars ([article](https://www.forbes.com/sites/michaelnoer/2011/11/15/pablo-escobars-son-forbes-is-lying/)).
Comment: See also this [2009 Forbes article](https://www.forbes.com/forbes/2009/0330/102-cocaine-king.html), which describes a little how El Chapo made his money: "In 2008 Mexican and Colombian traffickers laundered between \$18 billion and \$39 billion in proceeds from wholesale shipments to the U.S., according to the U.S. government. Guzmán and his operation likely grossed 20% of that–enough for him to have pocketed \$1 billion over his career and earn a spot on the billionaires list for the first time."
Answer: Not sure an economist can answer this particular question about Escobar's wealth and not only because all the given estimates are uncertain. A more interesting question for an economist (or at least for me) would be: What is Escobar's (a drug firm) mark-up? Or what is the economic size of the international market for cocaine?
The most serious source of information I was able to find is the 2012 World Drug Report of the United Nations Office on Drugs and Crime (UNDOC). UNODC estimates suggest that

The total retail market for cocaine amounts to some US $85 billion in 2009 (p.70).
Columbian production proxied in terms of hectares is around 89% (based on 2009's estimates (68,000+73,000)/158,800 - Table 12).

So, if you assume that all Columbian production is produced by Escobar's cartel his total benefit is about USD $75 billion for the year 2009.
Edit: However, we cannot assume that Escobar's cartel got 89% of the retail value (thanks to @Alecos Papadopoulos for this point). The USD 75 billion is the equivalent of the "box office" for a movie - but the producers of the movie (i.e. Escobar's cartel) do not get all the box office.
Then, the question is what is the proportion retained by the Escobar's cartel? I have no clue! However, Levitt and Vetakesh QJE paper document that "earnings within the (drug) gang are enormously skewed (..) with high-level gang members earning far more than their legitimate market alternative." So, by extrapolating from this result and assuming that the drug market is vertically integrated and controlled by the Escobar's cartel, we may speculate that the latter (and Escobar himself) may get a big part of the box office.
In this report, you may also find more reliable estimates about

The total number of cocaine users: 16 million (Table 7)
and the estimates per region.
Purity-adjusted prices per gram in those regions

So if you find some data on consumer's average consumption and Escobar's production you may get a better estimate of his wealth.
Comment: You are assuming that Escobar's cartel got 89% _of the retail value_. This is not the case. The USD 75 bil is the equivalent of the "box office" for a movie - but the producers of the movie (i.e. Escobar's cartel) do not get the box office. The theaters (i.e. middle-men) get a piece of the action, and it is not small.
Comment: @AlecosPapadopoulos you are right and I will add this point. However, [Levitt and Vetakesh QJE paper](http://pricetheory.uchicago.edu/levitt/Papers/LevittVenkateshAnEconomicAnalysis2000.pdf) document that "earnings within the (drug) gang are enormously skewed (..) with high-level gang members earning far more than their legitimate market alternative." So, by extrapolating from this result and assuming that the drug market is vertically integrated and controlled by the Escobar's cartel, the latter may get a big part of the box office!
Comment: At least according to Wikipedia quoted sources, "[Escobar's] cartel, at the height of his career, supplied an estimated 80% of the cocaine smuggled into the United States, turning over US $21.9 billion a year in personal income." So your 89% figure is probably not too far off.
Comment: Good to know! Thanks. I am curious about how did they estimate his personal income.
Comment: My numbers make more sense if I span them over 10 years. Thanks.
Answer: I didn't go through all that thinking and analysis as I see in this post, but while watching Narcos (both seasons so far), listening to the narration it seems the drug business is really just a logistics business, the value lies in insuring that the end user gets the product all cost even in human casualties.Every possible cost is factored into that value, so if you the manufacturer control every aspect of the supply chain, including insurance on the product. You can have a mark up as high as you want 1000%, 5000% if you want. Target a market that has the cash to burn, literally like the US or some specific areas of it, it really is that simple to be extraordinarily wealthy.
Comment: You may want to reread that chapter on monopoly price setting. Being a monopolist does not mean you can make arbitrarily high profits.


What does "pesas un huevo" mean?

Question: I am trying to figure out what pesas un huevo means.  I know that huevos sometimes translates to testicles, so is this sexual/vulgar?
Comment: Is there any context? In Chile is common expression "pesas menos que un huevo", which means that _you have no authority or power_.
Answer: Huevos besides testicles is also used as a intensifier. So the phrase:

Pesas un huevo.

is translated as:

You're heavy as hell.

You can use it with lot of things.

Me importa un huevo. [In don't give a shit]
Me costó un huevo. [It was hard as shit]
Caminé un huevo. [I walked a lot]

And yes, it's vulgar, but pretty normal.
Comment: I agree that is vulgar, but I don't think is as rude as the English word "fuck". I think is more like "Shit" (e.g. from your examples: "I don't give a shit"). Also "Me costó un huevo" has some ambiguity: "It was difficult as hell to do"  vs. "It was so damn expensive".
Comment: I'm from the US, but speak Spain Spanish (un variante asturmadrileño).  From what I can tell reading on-line, Argentina and Chile also use it.  It can also mean very little as much as it can mean a lot: *cuesta un huevo* (muchísimo) vs *me importa un huevo* (poquísimo).
Comment: I agree with you, I'll change that.
Comment: It's definitely not just Mexican, though.
Comment: I'll change that too, where are you from?
Answer: In Spain, it's equivalent to "pesas mucho". In English it would be "You're very weighty"
Answer: We use that phrase here too, in Andalusia. And yes, it's translated to:

You're heavy as hell.
Answer: Is the equivalent as your are weighty - same as "pesas mucho" o "estas super pesado"
Comment: "estas super pesado" could be understood as something closer to "you are so annoying", e.g. "Estas super pesado con lo de tu amigo Luis. Quieres cambiar el tema ya, por favor?"
Answer: Hay muchas expresiones sobre partes del cuerpo que se usan en el sentido de "un precio muy alto":
Ese coche cuesta un ojo de la cara.
Ese coche cuesta un riñón.
Ese coche cuesta un huevo [en el sentido de un testículo].
La expresión "un huevo", al contrario que las demás, ha extendido su uso a otros contextos con el sentido general de "mucho":
Trabajas un huevo, pesas un huevo (trabajas mucho, pesas mucho).
Posiblemente, estas expresiones provengan de antiguos castigos o penas:
Ese crimen te costará la cabeza, el cuello, un ojo de la cara [= como castigo te cortarán la cabeza, te cortarán el cuello, te sacarán un ojo de la cara].

What does "pesas un huevo" mean?


Reclaim search console property ownership after the owner who invited me has been removed

Question: I have access to search console but the owner who invited me left the company. Do you know how to claim ownership for our existing property?
Answer: Have you tried adding the site in search console yourself and then adding the .txt file verification at the root of the domain?
You could also delete the current .txt file on the server and this should eventually cause search console to remove the previous ownership. You'll most likely lose the data you have in this process, but you'll get to reclaim ownership once the current ownership drops from the verification.txt removal.
Answer: There are many ways to verify ownership of your website.   You can do so through any of methods that Google supports:

HTML file upload
Domain name provider
HTML tag
Google Analytics tracking code
Google Tag Manager container snippet
Google Sites
Blogger

Google has a help document with detailed instructions.  It includes instructions on how to change your verification method and instructions for each of the individual methods that you might choose.


Why is the longest block the one that gets accepted by all the nodes?

Question: I'm confused about one of the core principles of Bitcoin.  When various nodes are confirming transactions, why does the longest block win out?  That is, why doesn't the system allow whoever confirms a transaction or group of transactions first be the block that all the other nodes accept?  I realize there has to be some logic in the situation where two nodes submit confirmations at the same time, but what problems would get introduced if the node that confirmed a group of transactions first, regardless of the size of the block, win?
Answer: The problem here lies in a misunderstanding. It's not the longest block that wins out, but the longest blockchain (read "the blockchain with the most cumulative difficulty"). The length of a single block is hereby irrelevant and in fact usually the node that first confirms a set of transactions wins.
Comment: Thanks but its your use of the word "usually" taht is the basis for my question.  Why not "always"?  What bad things could happen if the system let the first node that confirmed transactions to win?
Comment: If everyone always picked the first block that would be perfect, however, it's possible that nodes disagree on which block they saw first. If two blocks are found at the same height at almost exactly the same time (i.e. less than two seconds apart), it is possible that both propagate to part of the network and the one found later gets extended first. Then everyone would start following the new longest chain which wasn't built on the first found.
Comment: So to put a bow on this, if nodes disagree on which block they saw first, couldn't they just use the timestamp of when that block was formed?  Or am I misunderstanding how timestamps are used when calculating blocks?
Comment: @Dave: Timestamps are chosen by the author of the block and not necessarily accurate enough to be used as a tie breaker. The timestamp has fairly lose restrictions, it only has to be greater than the median time of the last 11 blocks and no more than two hours in the future.


Brush the dust from your feet vs cursing a town

Question: Is brushing the dust from your feet when you leave an area the same as putting a curse on it?
Comment: Hello and welcome to the site. This is in relation to one of the passages in the Gospels isn't it? Can you please [edit] this to quote from the exact verses you're thinking of.
Comment: Genni, do you refer to Matthew 10:14-15?  If so, you need to copy it out into the body of your question.  If you are thinking about another biblical scripture, then we need to know what it is. When you have a moment, please take the Christianity Stack tour to learn more about us:  https://christianity.stackexchange.com/tour Please also read these: How to ask a good question: https://christianity.stackexchange.com/help/how-to-ask
What topics are allowed: https://christianity.stackexchange.com/help/on-topic
Answer: Jesus said this to his disciples prior to sending them out:

If anyone will not welcome you or listen to your words, shake the dust off your feet when you leave that home or town.  I tell you the truth, it will be more bearable for Sodom and Gomorrah on the day of judgment than for that town (Matthew 10:14-15)

My NIV Study Bible makes this comment:

A symbolic act practised by the Pharisees when they left an "unclean" Gentile area.  Here [in Matthew 10:14] it represented an act of solemn warning to those who rejected God's message.

It seems that the Pharisees had a tradition of shaking the dust off their feet when leaving an unclean place.  There is a similar event recorded in Luke 9:5:

"If people do not welcome you, shake the dust off your feet when you leave their town, as a testimony against them."

My NIV Study Bible makes this comment:

A sign of repudiation for their rejection of God's message and a gesture showing separation from everything associated with the place.

Another example is when Paul and Barnabas left Pisidian Antioch.  They shook the dust from their feet in protest against the Jewish community  who had stirred up persecution against them and who expelled them from their region (Acts 13:50-51). My NIV Study Bible makes this comment:

Paul and Barnabas did this to show the severance of responsibility and the repudiation of those who had rejected their message and had brought suffering to the servants of the Lord.

By rejecting Jesus' messengers, who proclaimed the nearness of the Kingdom of God, the people of that town were effectively rejecting the gospel message, and so they would have to answer to God for their unbelief. However, Paul and Barnabas did not place a curse on the towns from which they had been forcibly ejected. They came back to continue preaching the gospel, which was received by the Gentiles in those places, and they established churches and appointed elders.
Comment: Perhaps same idea as shunning or disfellowshipping a person. The goals are 1) declaration of separation from error, 2) warning the person/city of the danger, 3) inviting them to turn from error. If I find sources, I will try to comment or edit your answer.
Comment: Thank you for your comment but under no circumstances should you edit my answer.  Shunning, as practiced by some denominations today, has absolutely nothing to do with Jesus' instruction to his disciples to shake the dust off their sandals after leaving a community that rejected them and their message.  Jesus wasn't into shunning or cursing people/places.
Comment: Ok, I don't think it's the same, but the motivation can be similar. Nevertheless, I will be cautious not to suggest any edit to one of your answers unless I am quite sure you would be in agreement. Comments with information you can use are usually more appropriate in any case.
Answer: No, it has no hint at it. Jesus says bless the ones who curse you. Brush the dust means no longer stay in this town because it's no use to spend the time with people who will not change themselves, you better pay this time to those who will appreciate it. The most expensive thing is time.


Is there a restriction on how much chocolate I can carry in hand luggage on a Turkish airlines flight?

Question: I have flight from Frankfurt to Dhaka via Istanbul and i would like to take some chocolates. As I'm travelling light with only hand luggage, I was wondering if there is a restriction on how much chocolate I can take in hand luggage.
Comment: I couldn't find an authoritative source for this, but [this site](https://customsdutyfree.com/customs-or-import-duty-for-chocolates-and-pralines-truffles-to-bangladesh/) suggests there's no limit, but also that import taxes can be high once you import a value more then BDT1000 (around USD12). Obviously there's a limit to what you can put in carry-on luggage, but you'd have to consider whether the import is worthwhile after duty and tax has been paid.
Comment: The size of your hand luggage?
Comment: No import, only for personal purchase. @Redd
Comment: It's a backpack @Traveller 6
Comment: @faisal Anything you bring into a country is an import, whether it's for personal use or for some commercial purpose.
Answer: The governing constraints would be:

The volume and mass allowed by the airline for carry-on baggage for the flights in question.
Whether the item is allowed into any intermediate country where you are in transit, especially if you need to clear customs etc. in the intermediate country.
Whether the item would be allowed into the destination country, either in whole or up to a limit.
The import duties on the item and the cost-benefit analysis performed by you to determine whether this is worth it, including the opportunity cost of not using the money for some purpose other than buying the chocolate and the forgoing of taking some other item with you by occupying the space in your carry-on baggage.

You would research 1 by consulting your airline's website.
You would research 2 by both consulting the airline's website and the website of the transit airport.  It is possible that you would not need to clear customs while in transit within a terminal but would need to do so if you are transferring to another terminal.
You would research 3 and 4 by consulting the appropriate website for the destination country's customs service.
There's nothing magic about some item being brought by checked-in or carry-on except those things which are expressly forbidden from one but not the other or both.


Can anyone tell me how pedelec sensor in PAS bicycles work?

Question: While doing a literature review I found out about pedelec sensors (while googling some sensor to find torque applied by the rider). Is anyone who has used it willing to share the mechanism and can you briefly explain the mechanism?
Comment: Some use torque sensors, others use cadence sensors. But if there are any experts in the design of such systems here, they're probably not going to share very much.
Comment: From my understanding the torque sensors are used in higher end models as it can provide a smoother user experience by making it easier to more closely matching the user torque input, making it *feel* like you are simply stronger rather than the bike assisting your effort.  Whether or not this effect is important depends on your use case and target customer.
Comment: @Rider_X that's interesting - and logical as a cadence sensor is cheap hardware. I've never ridden a high end e-bike and tend to use manual control when I do borrow an e-bike because I don't like the automation especially when going very slowly to time a gap.
Comment: I think cadence sensor and speed sensor are interchangeable term because they are using the same mechanism : measure feedback over time.  Just add tyres radius, you will get the speed. :-D
Answer: From my experience working with electric bikes, most of what I saw were sensors that were mounted on the crank which measure your biking cadence. A sensor would be fixed around the bottom bracket, and then a ring of magnets would spin with the crank, 'tripping' the sensor every time a magnet passed.
They're called hall effect sensors and should be easy to integrate into your design as buying just the PAS sensor is relatively inexpensive.
You can find a Wikipedia page that covers Pedelec sensors here.
Answer: Compare to a torque wrench, Bicycle torque sensing are quite tricky. Checkout wikipedia torque sensor
Torque sensor need good material QC, electrical measurement component and good sensor, AKA : expensive. And it is difficult to make a DIY kit to install it properly. But the benefit is a direct feed to your motor, increase output when torque feedback are high = smooth pedal assist, save power when low torque sensed.  Pedelec that use torque sensor will also use speed sensor to cut off the motor when it reach the "legal limit".
OTH, speed/cadence sensing is much easier, you just need a simple feed : use a magnet or reflector to measure the gap and timing. So it works reverse : power always on, power cut off when the speed goes above the limit. "Power assistant output level" is pretty important here to save the energy.