Should OP downvote an answer or use the comments to improve the answer?

Question: I know this question might sound silly, but the idea that OP actually downvoted an answer because he/she didn't like it sounds sillier to me. An example here. As far as I know, OP has the ability to accept an answer. If he/she likes the answer, then simply he/she would accept it. If not, OP would just ignore the answer. Another thing, the downvote button is used when an answer is not supported by enough sources or was badly formatted, etc...If so, then is OP allowed to use the downvote button to downvote an answer he/she doesn't approve ? Shouldn't the OP use the comment's section to suggest an edit which might improve the answer instead of downvoting ?
Comment: see also: http://meta.stackexchange.com/questions/36442/is-it-rude-to-downvote-an-answer-to-your-own-question
Comment: @goldPseudo hmmm...interesting
Comment: Downvoters *do* see a popup encouraging them to comment, but commenting is *not* mandatory.
Answer: They are free to downvote if they don't find it useful. Note that Shia and Sunni have different opinions about which hadith are sahih, so what seems like a solid hadith to yourself may be considered a false hadith to someone else.
But to be honest, I wouldn't worry about it. A decent answer that has been unfairly downvoted will almost certainly be upvoted to 0 or -1, so you get a net gain in points for unfair downvotes.
Answer: Downvoting is used to indicate that an answer is not useful; even if the OP doesn't know the answer (hence why he's asking in the first place), he is in a position to know whether any given answer is actually useful to him.
However, I find that oftentimes when the OP is downvoting an answer, it's because the question itself is poorly written (this is just a general case, I am making no judgements on the linked question); it is as much a responsibility of the OP to write a question that attracts useful answers as it is for the answers to actually be useful.  If the OP is regularly downvoting answers that look to be exactly what the question is asking for, the question itself probably needs to be edited to clarify what OP actually wants in an answer (or closed as NaRQ).
For the most part, however, don't worry about it.  Downvotes happen, and often for no logical (or at least logically explained) reason.  What is, or is not, "useful" is very open to interpretation and personal whims.


How long does dropped loot last?

Question: When I'm running through Sanctuary killing the forces of Hell, sometimes I find myself in so much of a hurry that I fail to pickup a particular item or bundle of dropped coins.
Assuming I survive the pack of demons chasing me, how long do I have to pick up items left behind on the ground before they disappear into the aether?
Answer: It's based on the same timer as Diablo 2.
To wit:

Regular items and gold disappear after exactly 10 minutes.
Magic items will disappear after 20 minutes.
Rare, Set, Crafted, and Unique items will disappear after lying on the
  ground for 30 minutes.
Comment: Health globes are considered "regular items"?
Answer: Based on first-hand testing, low-quality (grey) items seem to despawn in about 5 minutes if they are off-screen (by at least 2-3 widths).  White items and gold last about 10 minutes, and I figure the Diablo II times would hold from there on up.
Do note, that if you're staring at the drops, they won't despawn, you need to be some minimum distance (1-3 screens) away.
As with everything else in the world, leaving and rejoining the game will clean up all of the litter you've caused.

How long does dropped loot last?


linux command to list details (like PID, VID) of connected devices to the serial port(s) (like RS232) of a computer

Question: with USB port we can search Product ID (PID) and Vender ID (VID) of connected devices by using lsusb command. Is there a similar way to get PID and VID if the same device is connected to RS232 serial port
Comment: RS232 predates Plug'n'Play by several decades.  There's no way detecting what you actually connected to the port.
Comment: You would probably have to interface with the device(s) that are connected on the RS232 port themselves directly or use protocol specific discovery functions to see what is living on the other side of the port. But either way you need to go up the network stack to get that info.
Answer: USB has a standardized method to learn device information including PID and VID. This information is available by the enumeration phase and takes place of the control endpoint. This is possible because there is an additional protocol on top of the raw data signals.
The RS232 serial port is much simpler and does not have similar functionality defined. Data is data, and its interpretation is up to the user/ program using that port. There is no VID nor PID defined for a RS232-connected device such as a printer.


does using copy content harmful for my website's seo?

Question: I am using copy contents from another similar websites but I always change the title a bit.But I want to know is this way good for my website that get result by google or not?!
Do I get visitors from google search or not?!
Answer: I don`t like to copy content but if you must do this for any reason follow this steps:
You must do some fresh content beside this.
Ex: 10 copy and 1 fresh. this will be enough but my advice for more protect and more improve at google, Do the next steps also:
Convert it to common content:
Do some changes in content like add fresh tow lines at top and bottom of content.
Add some good internal links to get good User experience to more protect.
Comment: This doesn't sound like good advice to me.  I'd only recommend copying content with the permission of the content owner (content syndication).   I'd recommend much more fresh content compared to duplicated content.  At least a 50/50 ratio, but ideal more like 80% fresh content.  Google's shingle algorithm can detect as little as seven words that are duplicated from another source.   Just adding a couple lines at the top and the bottom is not enough to distinguish a copy from the original.
Comment: @StephenOstermiller I added link of source and the reason about I have to copy content is that I don't have many employers to make custom content because it takes too much money and for now just can being update my website then maybe in future I have some guys to make custom and fresh content


Home experiment to estimate Avogadro's number?

Question: How to get an approximation of Avogadro or Boltzmann constant through experimental means accessible by an hobbyist ?
Comment: @KennyTM, that's not true.  They are related through the "ideal gas constant" R, a historically important proportionality constant in the ideal gas law.
Comment: @KennyTM , @j.c. : I had indeed the $R=k_BN_A$ relationship in mind, with R relatively easy to measure.
Comment: Avogadro's number ($6.02 \times 10^{23} \mathrm{mol}^{-1}$) and Boltzmann constant ($1.38 \times 10^{-23} \mathrm{J}\,\mathrm{K}^{-1}$) are two totally unrelated constants. You want to estimate both?
Comment: @jc: Ah you're right ($R=k_BN_A$). But the two constants are still independent from each other.
Comment: @KennyTM: measuring avogadro's number has historically always been equated with measuring Boltzmann's constant.
Answer: Your best bet is to try to replicate the experiments of Perrin who first measured Avogadro's constant.  This is a common lab in "Advanced Lab" courses in undergraduate or graduate courses, so you can probably find writeups and such via google.
The principle is to observe Brownian motion under a microscope and measure the diffusion constant.
Einstein's theory for Brownian motion relates the diffusion constant of a spherical particle to the temperature via the Einstein-Stokes law:
$D=\frac{k_BT}{6\pi\eta r}$
Here $D$ is the diffusion constant, $T$ is the temperature, $\eta$ is the viscosity, and $r$ is the radius of a small spherical particle.  All of these properties should be measurable at least crudely with home equipment.
The way I did this in my lab course was as follows.  We had access to a microscope with a CCD camera which allowed digital video recording, as well as samples of monodisperse polystyrene particles (which are commercially available, and labeled with their size).
Suspend the particles in water (the viscosity of water is well known) at room temperature and place on a slide (better, put a thermocouple in your sample).
Take video of the particles Brownian motion, and then using something like John Crocker, David Grier, and Eric Weeks's celebrated particle tracking code extract 2D (or maybe 3D?) particle trajectories (i.e. $x(t)$, $y(t)$.
Now plot the mean squared displacement of particles versus time.  The slope of this curve is the diffusion constant, which then yields an estimate for $k_B$ via Stokes-Einstein.
To recover Avogadro's constant, you need the ideal gas constant $R$, which is measured through independent means; typically via macroscopic thermodynamic experiments which probe the slope in $pV=nRT$.
Answer: Electrolysis.  Run a current through a weak acid, and measure the current going in and coming out.  Hydrogen ions in the acid will capture electrons and bond to each other to form hydrogen gas.  If you accept a measured value for the charge of an electron, you can find the number of hydrogen molecules liberated.  Then measure the volume of hydrogen formed at STP.  Avogadro's number is the number of molecules in a gas at STP with a volume of 2.2*10^-2 m^3.
Comment: I was going to ask you if Millikan & Fletcher's oil drop experiment was based on Avogadro's number, but I went and looked it up. He did use a slightly inaccurate value for the viscosity of air, though, and the article quotes [this interesting observation](http://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan.27s_experiment_and_cargo_cult_science) from Richard Feynman.
Comment: "Cargo Cult Science" - a classic!
Comment: If you don't trust the elementary charge, you measure $\mathcal{N}e$ which is an interesting step anyway.
Answer: Well, addressing only $N_A$, and allowing that it only gets you halfway there: Carl Sagan did a bit on Cosmos for estimating the size of a oil molecule. Put a known amount (both volume and mass) of cooking oil on a calm body of water and wait for the slick to diffuse to it's maximum contiguous area. Estimate the area.{*} Divide the original volume by that area and you have a rough value for the linear size scale of the molecule and thus how much volume it occupies. (We're neglecting issues of aspect ratio and polarity here so this is only a order of magnitude value.)
Now, if you have the molecular mass (from a mass spectrometer or some such) you're got all you need.

{*} A challenging step, but I'd use a photograph with some know length reference for scale and a planimeter. If you're not familiar with these instruments get ready to geek out. Very cool.
Comment: The experiment is from Agnes Pockels 1891 . To be honest: it does determine the cross section of an oleic acid molecule. To convert to Avogadros number You have to add some assumption on ratio of diameter/length of the molecules.
Comment: I remember doing this in a high school lab. We were very pleased to get answers right to just over one significant digit with really low-tech materials. Doing it in a larger body of water (swimming pool or lake) would be a good way to get more significant digits. We used basins that were less than two feet square, so our oil slicks had to be quite small.
Comment: +1 : Without the molecular mass, I've already an estimate of the number of molecules in a macroscopic sample, which is the order of magnitude of Avogardro's constant.
Comment: This will not work with "oil"!  The experiment uses oleic acid to get a monomelecular film. The experiment is from 19th century, not Carl Sagen.
Comment: To improve precision one uses a diluted solution of oleic acid in some petrol ether. You can meter a bigger volume then and the petrol ether will evaporate.
Comment: Do you know which episode of *Cosmos* it was? I'd love to see it/try the experiment myself.
Answer: To get a rough estimate of the Avogadro number, one can also use a method similar to that used by Loschmidt ([1] http://iweb.tntech.edu/tfurtsch/Loschmidt/LOSCHMID.HTML). Gas viscosity can be measured (see, e.g., http://www.phywe.com/index.php/fuseaction/download/lrn_file/versuchsanleitungen/P3010201/e/LEC01_02_LV.pdf - gas flow through a capillary is measured there). Gas viscosity is equal (up to a coefficient) to a product of gas density, average molecular speed, and the mean free path [1]. As the average molecular speed is of the same order of magnitude as the sound velocity in gas, one can estimate the mean free path (I assume that it is not too difficult to measure sound speed). The size of a molecule equals (up to a coefficient) the mean free path times (liquid volume / gas volume) (http://en.wikipedia.org/wiki/Loschmidt_constant ).
EDIT (9/28/2013): It is not easy to measure volume of liquid air at home, as its temperature is very low, but the above measurement can be performed with CO2, as solid CO2 (dry ice) is easily available (it costs about a dollar per pound, as far as I know). It does not matter for our purpose that dry ice is solid, rather than liquid.
Comment: @Ben Crowell: I gave a link to a description of such an measurement: http://www.phywe.com/index.php/fuseaction/download/lrn_file/versuchsanleitungen/P3010201/e/LEC01_02_LV.pdf . I may be wrong, but the equipment looks cheap, and, according to my quick estimate, the flow is  laminar.
Comment: Is there a simple home experiment to measure the viscosity of air? In most examples involving drag, I guess the Reynolds number would be too high...?


How to command the raspberry pi to mute and unmute its microphone

Question: I'm using a raspberry pi for a custom voice assistant I'm building. I need to mute and unmute the microphone for certain parts of the program I'm running. Is there a simple lx terminal command to do this? I'm using a voice hat from AIY projects if that makes any difference. I'm not using a usb mic.
Comment: if I have to start a bounty for this please upvote this question so I can continue to ask questions in the future
Answer: Try amixer:
amixer sset 'Capture' cap
amixer sset 'Capture' nocap

You may have to find out the control name for the microphone in your setup if you use additional hardware. amixer scontrols will list the controls you have.
There's also pactl command which should work on PulseAudio level. Identify the mic in the output of pactl list sources and then mute / unmute the source by number
pactl set-source-mute 0 1 # mute source 0
pactl set-source-mute 0 0 # unmute source 0

Comment: please explain the "pactl" more, my rpi recognizes the microphone on pulseaudio. thanks for the info so far
Comment: You can also do `amixer sset Capture toggle`.
Answer: If you are building voice assistant, instead of muting microphone. I suggest to disable / enable the wake word listener. If you are using MyCroft, then MyPrecise is the work word listener which you can disable and enable when required
Comment: That is not how my recognizer works, I specifically need the mic muted
Comment: Try

**amixer set Mic nocap** to mute &

**amixer set Mic cap** to unmute
Answer: I am not aware of any shell commands that is designed for it, but if we assume your microphone is connected via USB, you can disable and enable the specific USB port.
First check the path of your device via lsusb -t.
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M

To disable hub: echo '1-1.1' | sudo tee /sys/bus/usb/drivers/usb/unbind. You can again enable it via binding it. The detailed discussion is available here.
Comment: this is not a usb device it is built on a Aiy kit
Comment: sorry for not mentioning that


get location from drone video with command line tools

Question: How to extract location data from drone video (DJI Mavick Pro 2) by command line? I tried both ffprobe and exiftool, no result. But as for the videos shooted by Android phone all is well.
Answer: It's likely that the drone's footage doesn't contain any location data, but if you convert the drone's logfile to CSV with a site such as airdata you can get the geolocation and correlate it to your footage. I'm sure there are other sites that do this task for free, but I'm not sure what the original file format is.
Assuming the data is valid, you could use something such as RaceRender to overlay the data. Here is the specific documentation for that task.
All will be well on with your Android-recorded footage as GPS data is saved in the file itself (if enabled, of course).


To do list with custom rewards to task

Question: Is there a to-do list app that allows you to add rewards to tasks. And each category of rewards to be collected after you accomplish a task? Say you put a price of 2$ to achieving tasks. After you accomplish tax x, those 2$ to be accumulated.
Answer: There is an android application that gamifies the everyday choires and has a to-do list. This is as close as something is to what you seek. At least as far as I know. Check it out : Habitica

To do list with custom rewards to task


"I didn't realize"

Question: Is the phrase "I didn't realize" always followed by a clause in the Simple Past tense, or it can be followed with other tenses as well?
For context: "I didn't realize there were times you inadvertently dramatized things" vs "I didn't realize there are times you inadvertently dramatize things"
Comment: I look forward to the real answer. But also consider "I hadn't realized". I think the following clause could certainly use other tenses.
Comment: Consider the following: "When we started this class, I didn't realize you would be such a difficult lab partner."
Answer: In your example, both are grammatical and natural, and they mean the same thing.
Comment: Have you a reference to back up this assertion? Answers without supporting references come across as (and sometimes are) mere opinion, and are sometimes wrong.

"I didn't realize"


Light switch specs - max amps vs. watts

Question: I've been replacing light switches in my house to Lutron switches, because I think they look pretty.
I've noticed that Lutron sometimes specifies a switch as having max load of 600 watts, and sometimes as 5A. Why this variance? Since our electricity in the US is 120V, aren't these two the same? Thanks!
Comment: A quick google finds that Lutron's variable speed fan controllers are generally specified with ratings in amps, often 5, while dimmers specify watts.  Is that the distinction you mean? Or are there other examples?
Answer: Power Factor
VA and Watt are sort-of the same, but not exactly. The difference is based on the power factor.
From a practical standpoint with residential lighting these days it makes little difference because with LEDs (and even with fluorescent), 600 Watts is a lot of light. On the one hand, with incandescent bulbs (a simple resistance load), the power factor is essentially 1, which is ideal, LEDs and fluorescent use so much less power that for typical residential usage this more than makes up for any power factor issues. It is easy to hit 600 Watts with incandescents - 10 x 60 or 6 x 100. But with LEDs, a 100 Watt equivalent might use 14 Watts, so it would take an awful lot of lighting on one switch to get even close to 600 VA or 600 Watts, no matter what the power factor.
In commercial settings the power factor becomes a real consideration as even LED lights can add up when you are lighting a warehouse or an auditorium or other large area. Large customers often have charges based partly on the power factor and may install equipment to improve the power factor. But that is not normally the case for residential customers.
Comment: Exactly.  If you have LEDs with bad 33.3% power factor, 600W of LEDs could pull 1800VA (15A). I can see why Lutron is moving from W to A.  A and VA consider power factor, W does not.
Answer: There is really not a difference smart switches at 600w / 120v = 5 amps. This is the load the switch can handle. Simple snap switches are usually rated at 15 amps. The reason the smart switches have lower ratings than snap switches is because the electronics in the switch create heat the higher the load the more heat generated to maintain a safe box temp most manufacturers limit the wattage or they have larger heatsink flanges. With the latest smart switches that are LED compatible some of those top out at 3 amps or 360w. 360 is a huge amount of light when using LED's so larger wattage are not really needed. Why different types of smart switches for LED's ? Old smart switches used a little current through the lamps to power themselves because LED's are so efficient this small current caused them to glow and or flash so a new type of switch was needed. These switches require a neutral to power the electronics (thus the new code requiring a neutral in switch boxes) . I hope this information helps you understand what is going on. But there is no difference between 600w and 5 amp rated switches.

Light switch specs - max amps vs. watts


CentOS 7 VNC users dont share desktop session

Question: I installed VNC server on a CentOS machine. I set up a user, and then enabled the VNC server for them on startup following these steps: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-remote-access-for-the-gnome-desktop-on-centos-7. I can successfully log into the machine over VNC, but it appears that the VNC users are not sharing the same session... as if I log into the physical machine and start up a process, when the VNC connection is made, nothing is active on the desktop at all. What did I do wrong? I need VNC to allow users to log in and remotely debug software which may or may not have been started by someone logged into the physical machine
Answer: I'm not the expert, but I have a friend who uses ssh to easily access my machines, one I give him a login. It's one of many way, but it has worked for me. I don't think it's as secure as VPN, but it has worked out, with no incident so far. He does have a better vantage point to catch unsavory activities. It's not my field, but like I said, it seems to work well.
Comment: I appreciate the response... I ended up uninstalling tigervnc entirely from the machine, and used the built in vino server... the only issue is that I  had to disable encryption on the server to support connections from an ultra vnc viewer, due to type 18 not being supported.
Answer: You could use x11vnc for this.
As Root (sudo -i):
yum install x11vnc
x11vnc -storepasswd /etc/x11vnc.pass

printf '[Unit]\nDescription="x11vnc"\nRequires=display-manager.service\nAfter=multi-user.target\n\n' > /etc/systemd/system/x11vnc.service
printf '[Service]\nExecStart=/usr/bin/x11vnc -xkb -noxrecord -noxfixes -noxdamage -auth guess -display :0 -forever -shared -rfbauth /etc/x11vnc.pass -usepw \nExecStop=/usr/bin/killall x11vnc\nRestart=always\nRestartSec=150ms\n\n' >> /etc/systemd/system/x11vnc.service
printf '[Install]\nWantedBy=multi-user.target\n\n' >> /etc/systemd/system/x11vnc.service
systemctl daemon-reload
systemctl enable x11vnc.service
systemctl start x11vnc.service

That will share the primary display with anyone who connects and knows the x11 password you set.
less /etc/systemd/system/x11vnc.service

Look at the ExecStart line to see what arguments it is using, those are documented here: http://www.karlrunge.com/x11vnc/x11vnc_opts.html


Relevance of compositional key?

Question: Listening to Bach's Sonata No.4 for violin and harpsichord in C Minor made me wonder; does the key music is written and played in, have specific relevance to the compositions mood?
Comment: Well, heck. I was in the middle of writing an answer for this. I'll go post it on the other post.
Answer: For Bach, absolutely. Instruments were tuned differently back then, so the difference between keys and moods was quite significant. Equal Temperament neuters many individual characteristics for the sake of uniformity.
Comment: I thought equal temperament (ET) neutered many keys' individual characteristics for the sake of tolerability. Older tuning systems like Pythagorean tuning and just intonation typically create at least one dissonant "wolf fifth" in the chromatic scale. This makes switching to distant keys within one tuning system sound ugly. Bach wrote music in 24 keys for "Well-Tempered" keyboards, and well temperament is close to but not quite ET. ...Ah, when I look up well temperament, there are several such tuning systems, so it does seem that the musical world agreed on ET for consistency's sake.
Comment: @Dekkadeci - yes, well you're not altogether wrong either. At some point everyone got together and decided that all the keys would be a lot more tolerable if they were uniformly out of tune.

Relevance of compositional key?


Recommended period for archiving boarding passes?

Question: Should I throw away any paper boarding passes after landing and collecting my luggage? Or are there any considerations why it is recommended to keep them archived for some period of time? (For how long?)
Comment: Based on some other questions/answers here, you should probably keep them until after you have passed border control, if doing so.
Comment: I keep everything until I am safely back home.
Comment: Keep them at least until the miles show up on your frequent flyer account.
Answer: There is no time required to keep them. Throw them away whenever you want.
It is better to still keep them digitally, even in an old email.
Some uses for keeping them:

Claiming compensation
Travel record history
Memory logbook
Bookmarks (paper only)
Claiming miles for flights
Future discounts (either on flights or other perks offered by the airline)

If you do bin them, dispose responsibly  to not reveal any private information. Even your barcode could contain information about you.
If there is no electronic access whatsoever even online with the reference, i recommend keeping them for a few months and then it's your choice if you want to keep them for memories/other uses.
Comment: Sure and thanks, but I'd like to prefer the recommended way (in help center) - to wait for some time before taking such actions.
Comment: What about those passes which were printed at the check-in or transfer desk so there is no a access to their electronic version?
Comment: @miroxlav if there is no electronic access what-so-ever even online with the reference, i recommend keeping them for a few months and then its your choice if you want to keep them for memories
Comment: @miroxlav ok, if my answer helped please upvote it by clicking the top arrow and/or pressing the tick. Thanks
Comment: @miroxlav ok, no problem


Arduino UNO, using 5V and 3.3V

Question: I am newbie in Arduino (using UNO) and as I have 2 components that I wish to connected that one needs 5V and the other need the 3.3V, is it safe to connected them together next to each other?
Comment: In general, yes: you would just connect the 5v component to the Arduino's 5v output pin, and the 3.3v component to the Arduino's 3.3v output pin. They should share the same ground connection. Just make sure not to give the 3.3v component 5v power.
Comment: You may put a potentiometer to change and organize the voltage, if you need.
Answer: If a component needs 5V it must be connected to 5V. If it needs 3.3V it must be connected to 3.3V.  Connecting a 3.3V component to a 5V supply is a sure fire way of destroying it.
Furthermore, since the Arduino's main chip is a 5V device, if you want to connect it to a 3.3V device you must use some form of level translation so that the 5V signals from the Arduino don't damage the 3.3V device. Also it may (though not always) be necessary to convert the signals from the 3.3V device to a level that the Arduino can understand (5V).
Comment: "sure fire way" - pun intended?

Arduino UNO, using 5V and 3.3V


What happens if a player enchanted by cruel reality has Tamiyo, Collector of Tales on the board?

Question: A player has Tamiyo, Collector of Tales on the battlefield, and is also the target of opponent's Cruel Reality.
The player with Tamiyo can not sacrifice her, but does he lose 5 life when Cruel Reality triggers?
Comment: Sigarda, Host of Herons and Tajuru Preserver also prevent sacrificing permanents, and will have the same result (lose 5 life)
Answer: The player will lose 5 life.
As Tamiyo states, effects controlled by an opponent (such as Cruel Reality) cannot make you sacrifice permanents. Cruel Reality also specifies what happens if a player can't sacrifice a permanent when the ability resolves. It doesn't matter for what reason the player can't sacrifice a permanent, whether they have no permanent left to sacrifice, or another effect prevents the sacrifice.
With different wordings of Cruel Reality, the Tamiyo player could get around both the sacrifice and the life loss. Cruel reality could read:

At the beginning of enchanted player's upkeep, that player chooses one:

Sacrifice a permanent

lose 5 life.

The player could choose to sacrifice a permanent, but can't because of Tamiyo.
It could also read:

At the beginning of enchanted player's upkeep, if that player controls a permanent, that player sacrifices a permanent. Otherwise that player loses 5 life.

In that case, Cruel Reality would also try to make the Tamiyo player sacrifice a permanent and not cause 5 life loss.
Comment: It means more generally that there is no choice involved in Cruel Reality's effect. If you can sacrifice something, you have to.
Comment: @Styxsksu As my answer states, you will lose 5 life. Generally, you are not allowed to choose anything in any situation unless a rule or effect tells you to. Tamiyo's effect straight up prevents sacrifices caused by your opponent, rather than allowing you to choose whether or not to sacrifice, so you can't choose.
Comment: There is a ruling for Cruel Reality that states "The enchanted player can't choose to lose 5 life if they have a creature or planeswalker that can be sacrificed.". So this ruling is not applicable because no creatures or planeswalkers cab be sacrificed in this case?
Comment: Can you choose to sacrifice something in this situation or are you forced to lose the 5 life?
Comment: Considered revising this too include Doom Foretold?


Does spraying oxytocin in the face of a ferocious dragon pacify it?

Question: Instead of a pepper spray I like to adopt a more friendly approach towards hostile animal such as a fridge sized dragon, with an aerosol spray containing oxytocin of course. I think this chemical can induce powerful feeling such as affection and maternal instinct in animal so my question is would it works on an approaching dragon which is baring it's teeth and salivating profusely? This is in collaboration with SPCA and WWF to celebrate World Dragon Day, hooray!
Comment: Oxcytocin - in mammals yes. Lizards use something else - argine vasopressin, but you're discounting attachment. Just because a mother loves their baby, doesn't mean she won't fight to the death anything that threatens it.
Comment: They also might be evolved from birds, as the more recent theories suggest about dinosaurs. Oxytocine probably wouldn't work there either. Besides, maternal instinct doesn't necessarily mean maternal instinct toward YOU. It might simply mean that instead of snacking on you, it'll take you to its nest for its young.
Comment: A pheromone would be more appropriate for your intended change in behavior. It would need to have been developed from extracting dragon pheromone, though. So it may be difficult to obtain or manufacture.
Comment: Are you not worried that the oxytocin could also affect the woman spraying it, and that the result could be little fridge-sized dragon babies 9 months later?
Answer: This is extremely unlikely for a range of reasons.
Firstly, note that pepper spray works because it has an immediate irritant effect on the eyes, throat and lungs. It isn't required to cross the lungs into the bloodstream, be circulated around the body, be taken up into the brain, modulate a bunch of nerve responses, trigger the secretion of a bunch of other chemicals and ultimately, hopefully, cause a change in behavior. Packaging oxytocin in such a way that it is stable for storage, and can be freely aerosolized into very fine particles, and can reliably reach deep into the lungs and be absorbed in a strong-enough concentration from a dispersing cloud of droplets in the air is a difficult problem in pharmaceutical engineering.
Secondly note that the amount of chemical that will be inhaled is very difficult to control. It would be very easy (indeed likely) that too little will be inhaled, and inhaling too much is unlikely to cause anyone to become extra snuggly, but is more likely to have unpleasant effects you weren't banking on.
Thirdly, just because oxytocin moderates maternal bonding doesn't mean that it has no other effects. In humans it stimulates in-group bonding and behaviors likely to benefit the in-group over the out group (eg. the role of oxytocin in self-serving lying) and can also have interesting effects on suppressing risk-aversion. Consider that this might make a dragon more likely to see you as ideal food for its offspring, and/or more likely to fight harder to defend its kin. In humans, oxytocin levels are also strongly associated with sexual arousal, and maybe transforming a large angry hungry predator into a large angry hungry horny predator is not quite the defence that you might be looking for.
Lastly, there's no guarantee that oxytocin works on dragons at all, nor is there any guarantee that it works the same way on male and female and juvenile dragons. Maybe it has no effect, maybe it just moderates appetite. Honestly, you'd be better off with a decent gun. You can salve your conscience afterwards, as you'll probably still be alive enough to have a conscience.
Comment: Oxytocin is related to mating, but mostly as a result. It is helpful in the lead up to mating, but it is strongly related to many social bonding activities as well. Getting dosed with it will not automatically make you horny. Otherwise a +1 answer.
Comment: Shagged to death by a horny dragon. What a way to end the heroes journey. Throwing love potions was a bad idea..
Comment: @Pica I don't kinkshame.
Answer: Without something to deliver it quickly and possibly augment or complement the effects it has, it most likely would not have the intended effect. (Assuming mammal-like dragons) Oxytocin could calm the dragon down, but that might take effect after they've already eaten you. With something to deliver the oxytocin, they might get calmer; but if they're hungry and looking for prey, that might not matter.
Also, the effects of the oxytocin might only extend to other dragons, meaning that whatever effects it does have would just skip over you. We have a character (A very, very large wolf), and we decided after some research that he would become trusting and cuddly after being injected with a concentrated oxytocin-based serum, essentially using it as a truth serum with side effects. Later, he was able mentally force himself to be violent through force of will, so it depends on if your dragons are sapient, or just really want to eat you, at which point the spray would only be a mild deterrent. Of course, we took some liberties by adding unspecified extra chemicals to it, some of which are likely to be magical or non-existent in the real world, as the world this takes place in doesn't follow all of the rules we have. Also, if the dragon perceives you as a hatchling of some kind through the haze of whatever chemicals you threw at them; they might try to nest you or feed you. :)
Summary:
In the real world: Probably not, unless you tried really hard and used some other chemicals along with it; maybe even nanotech.
With some small liberties taken: Could be a decently effective non-violent solution to pepper spray, but would likely be illegal to use on any sapient beings (you are essentially forcing a mind-altering drug into someone).
With some large liberties taken: You can do anything with large liberties taken.
Answer: I would not advise it..
You'd get baked, then crushed and probably eaten
Of course, this love-drug will work fine with dragons. Their high level brain is compatible with this type of drug, it could make the dragon hallucinate. But as Starfish Prime already indicates, one of the effects of oxytocin is your dragon will regard you as a candidate mate. It would get horny.
As a human, you don't want any misunderstanding. A dragon's weight on top of you  would exceed certain limits and there will be fire involved in a dragon's mating ritual. For love and affection, you'd get baked first, and then crushed.. Afterward, when the love-drug has stopped working, the dragon will feed your remains to its offspring. Dragons often bake meat for their offspring, because young dragons have a weak immune system.
Comment: Oxytocin is not solely used in mating. Without further sexual stimuli it is unlikely that it would try to mate with you. In addition, the hormone does not set in hallucinations.


Creation of contract pending

Question: So I have tried to create my own token on Binance Smart Chain Network. For some reason in Remix my creation of contract is still pending while I looked on BSC and there it shows that transaction went successfully and contract is created. Does anyone knows why my creation in remix is still pending?
<code>
    pragma solidity ^0.8.7;

    contract Token {
        mapping(address => uint) public balances;
        mapping(address => mapping(address => uint)) public allowance;
        uint public totalSupply = 1000000000 * 10 ** 18;
        string public name = "name";
        string public symbol = "nam";
        uint public decimals = 18;

        event Transfer(address indexed from, address indexed to, uint value);
        event Approval(address indexed owner, address indexed spender, uint value);

        constructor() {
            balances[msg.sender] = totalSupply;
        }

        function balanceOf(address owner) public returns(uint) {
            return balances[owner];
        }

        function transfer(address to, uint value) public returns(bool) {
            require(balanceOf(msg.sender) >= value, 'balance too low');
            balances[to] += value;
            balances[msg.sender] -= value;
           emit Transfer(msg.sender, to, value);
            return true;
        }

        function transferFrom(address from, address to, uint value) public returns(bool) {
            require(balanceOf(from) >= value, 'balance too low');
            require(allowance[from][msg.sender] >= value, 'allowance too low');
            balances[to] += value;
            balances[from] -= value;
            emit Transfer(from, to, value);
            return true;
        }

        function approve(address spender, uint value) public returns (bool) {
            allowance[msg.sender][spender] = value;
            emit Approval(msg.sender, spender, value);
            return true;
        }
    }

</code>
Answer: For anyone who has similar issue in future. Basically token was created but Remix was not showing that I successfully transfered token into my wallet without doint anything specific

Creation of contract pending


Is it a good idea to test a live company website as part of an interview process?

Question: I got an interview task, which is to pentest the careers section of a company's website. I'm keen to play around with any website, and permission was given but this feels like a free pentest. I imagine that other candidates will perform a similar task, but is it a good idea?
Comment: Define "good idea"
Comment: Testing a live company website as part of an interview process is illegal in the United States, even if they gave you permission. They cannot request free, unpaid work. Run away FAST if they are trying to get you to perform free penetration tests.
Comment: Maybe they don't expect you to find anything, but just want to see your methodology.
Comment: @multithr3at3d Doesn't matter. This basically becomes "free consultation work" during an interview. If they wanted to see his methodology, they need to set up an environment in which to test this methodology.
Comment: Yeah, you guys raise good points. Thanks for the input!
Answer: A lot of companies are giving challenges as part of the interview process these days, mostly on sample apps, I've never heard of testing on a live site as part of an interview.
Do you have a paper trail? Is there an email from someone at a high level approving of this? If not I'd ask for an email from someone at the director level or higher that indicates you have permission. Then agree on a time and have everything in writing.
Are they looking for a free pen test? Maybe, but oh man is that shady if true.
Comment: Unpaid consultation during a job interview can be illegal in many places. This is not good advice even if they sign off on it because the company may be trying to obtain work for nothing. It doesn't take long to set up an exploitable web application or server, and there are many free services such as HackTheBox, so I highly recommend either moving on or saying no.
Comment: There's an email trail, nothing on paper - which is another thing that makes me skeptical besides it being a live site and sort of free work. Anyway, I concluded that I won't go ahead if it's not a dedicated test environment that is not related to anything they want to or already have deployed. Thanks


.tcl file not running

Question: I have installed ns2 on ubuntu 12.04. when I am trying to run .tcl file following error is showing up:
<code>ajay@ajay-Inspiron-535s:~$ cd ajay
ajay@ajay-Inspiron-535s:~/ajay$ ns old.tcl
couldn't read file "old.tcl": no such file or directory
</code>
Comment: "couldn't read file "old.tcl": no such file or directory" you sure the file exist?
Answer: Do you want to run it or open it? A tcl file is a script and running it equates to running the contents of the script, while opening it equates to viewing its contents only.
You will have to install a tcl library first.
You can download the installer from ActiveState Tcl.
After installation, you should be able to run the script
Depending on your script, you may not be able to run/execute it even after downloading and installing from ActiveTcl, and may receive errors like can't find package ....
This is because the ActiveState installation is only a bare bones Tcl interpreter.
If you encounter this problem, get a command prompt and type teapot update-self and, when this completes, teaport update. (The second command will take quite a long time.)
Even this may not fix things.

.tcl file not running


Understanding the Gibbs Free energy principle

Question: So, I have just derived that $dG\leq0$ for a closed system at constant temperature and volume. But, I am finding it hard to understand how this corresponds to the equilibrium state which has minimum Gibbs free energy. I mean, mathematically, it is a second derivative, so I am thinking like the change in Gibbs free energy can be either negative or zero, but how it can be minimum? It is simply the first derivative, for the function like $G$, for it to be minimum, both its first derivative should be zero and second derivative be greater than zero. How can I comprehend this relation regarding Gibbs free energy be negative?
Comment: Perhaps this might help: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thepot.html#c1
Answer:
The condition for $dG \le 0$ should be $T = const$ and $P=const$, instead of $V=const$.
$dG\le0$ describes the free energy change of a process, not a state. For a reversible process, $dG=0$, while for a irreversible process $dG<0$.
The second law of thermodynamics says: Isolated systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy. Minimum $G_{system}$ corresponds to maximum entropy $S_{system + environment}$. In this sense, minimum $G$ at equilibrium is true by definition, instead of being a consequence of $dG\le0$.
As far as we know, there are no perpetual motion machines. So every system we know has a minimum energy $G_{min}$. We say states of system that has $G_{min}$ is in thermodynamic equilibrium. Since $dG\le0$, we know every system is heading towards equilibrium, however slowly it may go.


How to make a shader that shows the direction of the normals relative to another object?

Question: We need a shader so that normals that look towards a third-party object color the mesh in white or its gradation.
Comment: subtract from empty position your current position (Texture Coordinate: Object). Normalize if you want the normal normalized. That's it.
Answer: Not sure it would be 100% correct,
but looks like the layer weight node would be what you need.
If you need an object's normals other than the camera to "track point" to another object, you should use an attribute node and that formula to match it.
Hope this helps!
Comment: Hi, thanks for the post. This site is not a regular forum, answers should be substantial, stand on their own, and thoroughly explain the solution and required steps. One liners and short tips rarely make for a good answer. If you can, [edit] your post and provide some more details about the procedure and how it works, perhaps add a few [images](https://blender.meta.stackexchange.com/questions/963) illustrating some steps and final result. See [How to write a good answer?](https://blender.stackexchange.com/help/how-to-answer), otherwise it may be converted to a comment.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


TypeError: Missing one required positional argument

Question: I am working on a game as a side project for fun and I have run into this error and I really don't know why it is happening...
Here is the code:
class players:
    def __init__(self, location, image_file, direction):
        self.location = location
        self.image_file = image_file
        self.direction = direction
        self.rect = self.image_file.get_rect()

    def turn(self, direction, playerImages):
        keys = pygame.key.get_pressed()
        if keys[pygame.K_a] == True:
            self.direction -= 1
            if self.direction < -3:
                self.direction = 3
        if keys[pygame.K_d] == True:
            self.direction = 1
            if self.direction > 3:
                self.direction = 3

        if self.direction == -3:
            self.image_file = playerImages[0]
        if self.direction == -2:
            self.image_file = playerImages[1]
        if self.direction == -1:
            self.image_file = playerImages[2]
        if self.direction == 0:
            self.image_file = playerImages[3]
        if self.direction == 1:
            self.image_file = playerImages[4]
        if self.direction == 2:
            self.image_file = playerImages[5]
        if self.direction == 3:
            self.image_file = playerImages[6]

        return self.direction, self.image_file

I call it like:
skierDirection, playerImage = players.turn(skierDirection, playerImages)

The error I get is:
Traceback (most recent call last):
  File "C:\Users\Owen\Desktop\coding compile file\SkiFreeX\SkiFreeX.py", line 129, in <module>
    main()
  File "C:\Users\Owen\Desktop\coding compile file\SkiFreeX\SkiFreeX.py", line 122, in main
    skierDirection, playerImage = players.turn(skierDirection, playerImages)
TypeError: turn() missing 1 required positional argument: 'playerImages'
[Finished in 0.385s]

Any ideas?
Answer: You are not supposed to call a class method directly, instead create an instance of that class:
p1 = players(your, values, here)
skierDirection, playerImage = p1.turn(skierDirection, playerImages)

To elaborate on the error you're getting:

TypeError: turn() missing 1 required positional argument: 'playerImages'

It's because turn needs an instance of players as first argument (self). A class method always gets passed the instance as the first argument, thus p1.turn(skierDirection, playerImages) will acutually pass 3 parameters to players.turn.
Answer: You have need to use () with class name
Follow below code
skierDirection, playerImage = players().turn(skierDirection, playerImages)


Mac App Store Character Set error!

Question: I'm having trouble with the Mac App Store.
It shows me error messages with question marks instead of normal letters as in the following pic.

Can anyone help me?
Comment: What version of OS X are you talking about?
Answer: Go to the Applications folder and start up the Font Book app and do File > Restore Standard Fonts and restart.
If that doesn't work, try a Safe Boot.
Answer: Best guess is font corruption at OS-level
Reinstall your current OS's latest combo updater - find it here & refine the search at top left for your actual current OS.

Mac App Store Character Set error!


How can I keep my biz website with Squarespace but my blog with WordPress

Question: I started my website with Squarespace, and while it's great for a static small-biz website, it's not working for a dynamic blog. I'd like to start a self-hosted WordPress blog but still keep the domain name as the same for both - www.cooksmarts.com. In my DNS manager, I've mapped my A Record to SS's IP address. How can I change it so that www.cooksmarts.com would take you to SS but www.cooksmarts.com/blog would take to WordPress blog?
Comment: Related: [Can a CNAME DNS record point to a subdirectory?](http://serverfault.com/questions/47175/can-a-cname-dns-record-point-to-a-subdirectory) at ServerFault
Answer: I'd recommend creating a sub-domain blog.mysite.com and pointing the A Record (or possibly a cname) for it to an alternative server.


Cannot RDP to Windows 7 with Remmina on 12.04

Question: Since I upgraded to 12.04, I am unable to RDP to a Windows 7 server. All I can see is a pop-up that says "Uable to connect to RDP server ". I am able to RDP using Vinagre, so that rules out any issues with my router or the Windows server.
As far as I can tell, there are no logs from Remmina and the Debug window shows a blank.
Any one got any ideas?
Thanks.
Answer: I too had the problem that I could connect to a Windows 7 machine and suddenly (after weeks) I got this error:
Unable to connect to RDP server
In my case I deleted the entry from ~/.freerdp/known_hosts and it then worked fine.
Comment: amaziing !!! I worked also for me. (Ubuntu 14.04 TLS) Thank you very much (+1)
Comment: Linux Mint 18: the file is now located here: ~/.config/freerdp/known_hosts
Comment: This fixed the issue for me as well. Apparently the server fingerprint changed and I needed to resync. A more verbose error would have been nice on remmina's part.
Comment: This worked for me as well, but it's a bit concerning why it should. When I diff the new file with the old `diff .freerdp/known_hosts{,.bak}` I see that the host key has changed. I encountered this issue after disconnecting the remote session (leaving the account logged in on the remote), going to bed, and then waking up the next morning to find that I couldn't re-connect.  After reboots on the local and remote machine, restarting the term service (Windows Server 2008), I found the solution here. Any idea why the host key should have changed?
Comment: Same goes for current debian testing, version 0.9.99.1.
Comment: I had multiple entries for the same machine (because of various assigned IP's over time by DHCP. Removed them all, and voila, worked (again). Thanks!
Comment: Worked on Ubuntu 12.04
Comment: I also have an ssh server (cygwin) on the remote and I was able to connect via ssh without issue so that host key apparently did not change, strangely enough.
Comment: XUbuntu 16.04LTS its located in `~/.config/freerdp/known_hosts2`. You can search for the file with `$ locate "freerdp/known"`.
Answer: Click Advanced tab in your Remote Desktop Preferences and choose RDP in Security drop down menu and save.
So far it works for me.
Comment: Or more generally, choose the authentication type that the server supports, NLA in my case.
Comment: Yes, this worked for me, too.
Comment: Yup, I needed this to get mine to work as well
Answer: I had a similar problem, getting the "Unable to connect to RDP server" message using Remmina and Ubuntu 12.04 to a Windows 7 machine.
It worked fine for weeks and then suddenly stopped.
What fixed it was going to ~/.freerdp/certs and deleting the problem server from that file.
The next time it connected, it asked for a new cert and worked fine.
Answer: I had this problem. Like you I had no output when running remmina on the command line and the debug window was blank. I solved this by removing the line in the file ~/.freerdp corresponding to the problem server.
Comment: filename is: ~/.freerdp/known_hosts
Answer: I have no idea why it worked, but I started changing settings one at a time. When I edited the connection properties, I looked on the "advanced" tab and changed the security from "negotiate" to "TLS", and voila, everything works.
Strangely, "negotiate" still works on the laptop, but at least I'm back in business with my bigger monitor :)
Answer: I haven't had any files in ~/.freerdp/certs/ so I went ahead and cleared the file ~/.freerdp/known_hosts with this command:
echo "" > ~/.freerdp/known_hosts

Be careful! This will erase the entire file. I only had one entry, so it was okay.
Afterwards connecting to the server Remmina asked me to accept the servers certificate, which I did, and everything was finally back to normal. I suspect that an update of Remmina or the RDP protocoll might be the issue.
Comment: I can't imagine why Remmina can't come up with a better error message than "Unable To Connect" but your solution saved many hairs on my head!!
Answer: I resolved this issue by activating the console mode for windows 2003.
Advanced ->
Protocol RDP
security = RDP
tick: Attach to console
Comment: This works fine for me, I was trying to connect to a Windows Server 2012 R2, so the last option was that I was missing. Thanks!


Why was radio contact with Pioneer lost earlier than with Voyager?

Question: Why was radio contact lost with the Pioneer probes much earlier than with the Voyager probes? The Voyagers were launched only 4 years after the Pioneers, yet the Voyagers are projected to last into the 2020s, while the Pioneers stopped transmitting in 1995 and 2003 respectively. Both were powered by RTGs as well.
Answer: Interplanetary communication is mainly dependent on signal strength (for transmission) and antenna size (for reception).
The Pioneers use a 9-foot antenna and an 8-watt transmitter. The Voyagers use a 12-foot antenna and a 20-watt transmitter, allowing a substantially stronger signal to be received on Earth.
Comment: the advantage is 5:1 when you calculate the size and power.
Comment: According to Aramis' answer, the Pioneers had a much higher-gain antenna which would give a stronger signal despite the weaker transmitter.
Answer: In addition to a better transmitter, the Voyagers have better power reserves: their RTGs supplied 470 W at launch, while the Pioneer RTGs supplied 160 W at launch. So the Voyager RTGs will take much longer to decay to a point where they can't power the spacecraft.
NASA seems to think RTG decay is the primary reason we can't receive Pioneer 10 any more:

Pioneer 10 made valuable scientific investigations in the outer regions of our solar system until the end of its science mission on 31 March 1997. The Pioneer 10 weak signal continued to be tracked by the DSN as part of an advanced concept study of communication technology in support of NASA's future interstellar probe mission. The power source on Pioneer 10 finally degraded to the point where the signal to Earth dropped below the threshold for detection in 2003.

We're not sure about Pioneer 11's fate:

The Pioneer 11 Mission ended on 30 September 1995, when the last transmission from the spacecraft was received. There have been no communications with Pioneer 11 since. The Earth's motion has carried it out of the view of the spacecraft antenna. The spacecraft cannot be maneuvered to point back at the Earth. It is not known whether the spacecraft is still transmitting a signal.
Comment: @JDługosz Good question. [Why has the Earth's motion carried it out of view of Pioneer 11's antenna?](http://space.stackexchange.com/q/14411/415)
Comment: So how wide is the beam from Pioneer 11 when it reaches our neighborhood?
Comment: I recently calculated that for Voyager, its beam is about 0.7 AU wide at the moment. Pioneer will be a bit wider due to the smaller antenna.
Comment: So wouldn't the Earth move in and out of the beam over the course of a year?
Comment: @JDlugosz - I would think that would depend more on the spacecraft's attitude towards earth (its xyz position). If the antenna is facing outside of earth's orbit, they will never coincide.
Comment: Yes, that would be an understandable explaination. But that's not what they said.
Answer: Pioneers
Several factors lead to the loss of signal.

Radiated power:  Pioneer 10's broadcast power is particularly low. 8 W at ~2.2 GHz ①
Very narrow beam; the antenna gain is +65dB, which means 1/(10^6.5) the broadcast surface area... which means a pretty narrow cone. (I don't know the math for the actual beam angle.)
Input power decreases - the RTGs still produce plenty of energy, but the corroding of the thermocouples results in progressively less input power to run the transmitters. (Corroded thermocouples are less efficient at converting heat to electricity.)
Continued drag on the spacecraft. ② This is relevant because Pioneer cannot continue to reorient indefinitely - fuel is a finite resource.
Budget cuts.

The combination of these factors leads to the cumulative failure.
Primary is that Pioneer is not producing intelligible data due to weak signal, so it was no longer cost effective to track Pioneer 10. Pioneer 11 shutdown was primarily due to power loss. ③
In looking at how the decision works - at the range they are at, the signal is very weak, and antenna accuracy (to keep Earth in the center of the antenna lobe) is a function of rotational control over attitude. Even so, the required dish size to get data to or from Pioneer 10 was a minimum 64m dish to have the required signal strength. As it goes further out, the minimum antennae to receive its signal increases. At present, only a handful of scopes can communicate with Pioneer 10 at all, and the data is so weak that it's unreliable.
The Pioneers used gas thrusters as their reaction control ④, which provides a fundamental limit to their pointing accuracy.
The drag of the interplanetary medium (IPM) and the solar wind are also issues. ② because the medium is not actually uniform, this results in slight differentials across the spacecraft, which, given the decades, are able to slow the spin and alter the angle. Keeping in mind that the IPM includes chunks of dust and even small pebbles, and the Pioneer velocities make a pebble impact comparable to a small caliber firearm hit, one at the right spot could wobble the spacecraft out of communication.
The exact cause of Pioneer 11 failure isn't actually known, but it's presumed to be power failure (as the telemetry showed decreasing power on a decay curve), possibly coupled with an impact event and/or short circuit. If it were knocked off axis, it might still be broadcasting but have earth outside the antenna's broadcast lobe. The knocked off axis hypothesis isn't likely, as the location is still on the predicted course.
The expectation of Pioneer 10 to continue to degrade in power consumption contributed in the public explanations of termination of the Pioneer 10 mission, equally as much as the expense of the 65m, 100m, and Arecibo antenna time, and the ability to spend that money on missions returning more data.
Voyagers
Voyager, on the other hand, has better thermocouples, younger thermocouples, more power produced, more power (18 w)⑤,  and while only a 48 dB gain, it's in a better frequency noise-wise (~ 8 GHz), it's still sending useful data from instruments, and had much higher surplus power at launch.
Voyager power losses have been a shallower curve than the pioneer program; more of the initial power available is still available. Further, the original power was much higher.
The instrumentation for Voyager included several more experiments that are not of use in the extended mission; they can be turned off with no loss of data gain. This allows more of the available power to be used on the ones that are relevant.
The Voyager missions as originally conceived of also included a longer operational period - more than 10 years was expected, versus Pioneer's 2 years.
To recap:

Voyagers 1 & 2

Better frequency (less noise).
Bigger dish & better aim.
More power in ship (both at start and at present)
More working instruments
working instruments on mission goals for current mission
not as far along the loss of power curve ⑥
still have significant fuel reserves so can stay pointed.
Designed for a longer operational period.

Pioneer 11

Power failure monitored resulted in expected failure to be able to compute and communicate about the time signal was lost
power failure curve precluded useful instrumentation for extended mission.

Pioneer 10

Instrumentation not suited for extended mission.
Signal strength and accuracy not conducive to the transmission of data.
Fuel reserves nearly depleted
probability of failure made continued contact not worth the money.

References
① http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1972-012A
② http://arxiv.org/pdf/1307.0537.pdf
③ http://nineplanets.org/spacecraft.html
④ http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009039.pdf  ⑤ http://www.uhf-satcom.com/misc/datasheet/dh2va.pdf
⑥ http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html
Comment: Do you have a reference for thermocouple degradation in the Pioneers vs. Voyager? I searched for that, but found no evidence the Voyagers were any better in that regard.
Comment: @Hobbes Not to hand, but there was mention made in a NASA document on thermocouples that the ones for the Voyagers were an improved design, leading onward to the newer designs used in the 80's... Mention is made on the ⑥ link that the corrosion on voyager isn't as far along as was expected. I've read so many NASA docs on power systems that I can't find the relevant ones when I need them :)


What happens in rugby if a penalty kick at goal goes into touch

Question: What happens if a team take elect to take a kick at goal and the ball accidentally or intentionally goes into touch?
E.g. what if they elect to kick at goal from their own 5m to run down the clock in the last minute of a game and then kick it into touch?
Would they still get a throw in to a lineout as if they had kicked the penalty from hand into touch?
Comment: Union or league?
Answer: In relation to Rugby Union:
If it was deliberate - as in the kicking team called for a penalty shot and intentionally kicked it into touch - then no, they would not be awarded a line-out.
Firstly, under Law 8 - Scoring

20)
If the team indicates to the referee the intention to kick at goal, they must kick at goal. The intention to kick can be communicated to the referee or signalled by the arrival of the kicking tee or sand, or when the player makes a mark on the ground.

Therefore meaning that once the signal for the shot at goal had been made, they cannot then decide to kick to touch.
Secondly, under Law 20 - Penalty and free-kick

8)
The kicker may punt, drop-kick or place-kick (other than for touch) the ball.

Implying that you cannot kick for touch from a place-kick.
In the old laws - that is to say, before they were restructured and simplified in 2018 - there used to be a clause on infringements made by the kicking team which said:

Unless otherwise stated in Law any infringement by the kicker's team results in a scrum at the mark. The opposing team throw in the ball.

Source for above is from the article linked at the end
Which I interpret to mean that if the kicking team deliberately kicked to touch off a place-kick, then the other team will be awarded a scrum at the mark of the previous penalty.

If it was unintentional - for example the wind was so strong it blew the ball out into touch, or the ball hit the post and bounced out into touch - then a lineout would be given to the defending / non-kicking team assuming that the ball was not touched by another player.
The latter of those two scenarios has actually happened - in 2016, against Australia, Nicolas Sanchez of Argentina took a penalty kick, which hit the post and bounced into touch. This resulted in a lineout to Australia.
The ruling for this can be found in a Law Clarification from 2006 (Clarifications carry the same force as Law)

Request
[...]
Following a penalty kick and after the ball was kicked, the ball hits the goal post and goes into touch without having been touched by another player.
What decision should the referee give?
Ruling of the designated members of the Rugby Committee
If the penalty kick is for goal, then it is a lineout defending team to throw in.
Law 21.4(d).

Note: the 21.4(d) is in relation to the old Laws structure
This was discussed in this article of the event.
Answer: In rugby union, if - in the very unlikely event - a shot at goal goes into touch, there are two possible scenarios:

If there is still time on the clock, the game would restart with a lineout and the team kicking would throw it in.
If there was no time left on the clock, the game would not restart with a lineout and the game would end.

This is a similar situation to if the shot at goal misses the posts and goes over the dead ball line. In scenario [1] if there is still game time, the game starts with a 22 metre drop out. In scenario [2], as there is no more game time, so game over.
In scenario [2] the kicking team has taken the 'advantage' to shoot for goal on the final play. They don't get a second chance.


Where can I find the dimensions of an object?

Question: In earlier Blender versions, the "Transform Properties" panel showed the object dimensions (i.e., bounding box: width, height, depth).  Now, it just shows location, rotation, and scale.
Answer: Press N to bring up the Properties Panel of the 3D View, the Dimensions are listed below Scale in the Transform panel (bottom right):
Comment: Thanks, I had been looking at the object "Transform" panel instead.
Answer: While CoDEmanX's answer is still correct for Blender 2.8, you have to have the Modeling view mode (bar at the top) selected and be in object mode for the dimensions to appear in the transform panel.
User serdar.sanri added this information here, however this question pops up first in the google search, so it might help to find this comment here, too.
As of Blender 3.0, Modelling view is no longer required.


Splashback tile to brick wall

Question: I am planning to install ceramic tile 50x200mm to brick wall as a splashback in kitchen. There is less gap with sink tap and brickwall so there is no enough space to add plasterboard on brickwall. Before there was old tile on splashback which I have already removed and there are small chipped on brick and not so smooth surface and gap between brick because of mortar. So is it ok to install tile directly to brick wall. If so what could be the best tile adhesive I can use and what thickness of trowel is good to use.
Answer: You should use thin set. Preferably a modified thinset, unless the tile manufacturer recommends against it.
The size of the trowel will also depend on what tile you are using. It is difficult to determine an exact size without knowing more about the tile you plan to use. Generally you will want a thickness of mortar that will fill the gaps and voids and still leave ridges above the surface to contact tile.
More info about the tile and maybe a pic of the wall and we can get you a more detailed answer.
Answer: Use thin-layer mortar to make wall flat, remember to wait as long needed - check mortar description, then use choosen water resist layer on wall and if possible on floor, then put tiles on chosen adhesive (mortar or glue) Read instructions on boxes/bags and do what is writen - if need some additional steps then it shall be writen in product description.
Or hire proffesional.

Splashback tile to brick wall


Can a disable person play cricket as others play?

Question: If a player is physically different from other players like if he has artificial body parts can he play cricket like others in ICC?
Answer: Yes, there are cricketers who play with prosthetic limbs, for example Tom Carter who plays recreational cricket in Wales. In the near future, I suspect it's very unlikely that an athletes with a prosthetic limb will compete with able bodied athletes at a much higher level than that due to the limitations that even the best prosthetics place on movement and balance.
On the other hand, there are of course various forms of cricket designed for athletes with disabilities, whether they be physical disabilities or mental disabilities; of particular note are blind cricket and deaf cricket.


Complicated SQL query vs datatable iteration and proccessing

Question: I have a three table structure in SQL Server 2012: people, connections and messages. The affected schema would be like this:
People: Id (pk bigint), name...
Connections: Id (pk bigint), IdPpl1 fk, IdPpl2 fk
Messages: Id (pk uniqueidentifier), Idconnection (fk), Messagetype (smallint)
On the Connections table, IdPpl1 and IdPpl2 are fk's to people Id. It could happen to appear in this table the same "two people" but swapping their column, E.G:
Id IdPpl1 IdPpl2
.. ...... ......
3     101    105
8     105    101
9     101    106
10    106    101

The above situation is correct. Actually, those are the maximum occurrences of these "two people" in the table.
The Messages table holds the information of which "connection" sent a message.
Id IdConnection Messagetype
.. ............ ...........
24            3           1
25            8           1
26            3           2
27            8           2
28            9           3
29           10           2

(Note: the messages are one-way, that's why there can be two rows in the connections table affecting the same two people: on the first row, one person is the sender and the other the receiver, on the second row they swap)
Given a People Id, I need a SQL query to show "least connectiontype messages mutually sent by mutually connected people" and an extra colum indicating if the messagetype matches or not. The result should be like this, for People Id 101:
Person_id Person_name IdConnection MatchingMsgType
......... ........... ............ ...............
      105        John            3               1
      106       Peter            9               0

The first row appears because of MsgIds 24 and 25. A potential row corresponding with messages 26 and 27 won't appear because a previous matching messagetype was found.
The second row appears because of  MsgIds 28 and 29, marking the messagetype as non-matching.
Currently I get all the "messages related to a person" and iterate through the datatable sorting, filtering and operating in-memory.
Would you go with a full-SQL solution (I want to preserve full isolation between app tiers) or is more suitable the datatable iteration?
Thanks in advance!!
Answer: Obviously it depends on the length of the resulting set of your current db query (the one resulting in all rows related to a user). It is not clear if rows are ever removed from you tables. If not, your solution does not scale, since the number of matching rows will grow for ever. If instead you can assert the the number of resulting rows has some bound (for example: the maximum number of connections a user can open at the same time) then your solution might be good enough.
Comment: Thanks for your input @manu-fatto: the row count should be no more than 300 rows in the worst case, and no: rows are not removed!


Is there a difference in terminology between the words "cryptogram" and "ciphertext"?

Question: I've noticed that certain security professionals use the term "ciphertext" while others use "cryptogram".  Is there any meaningful difference between those terms?  Or can they be used interchangeably?
Comment: Have never seen cryptogram in use.
Answer: They're grammatically different for sure, because cryptogram is exclusively a count noun, while ciphertext can be either a count or a mass noun.
Also, I can document that the term cryptogram is sometimes used in senses where it's definitely not synonymous with ciphertext.  For example, in the v2.2 specification of the Keyak cipher (a candidate in the ongoing CAESAR competition), p. 3:

The mode Motorist supports the authenticated encryption of sequences of messages in sessions. During a session, it processes messages and cryptograms. A message consists of a plaintext and possible associated data (called metadata in the remainder of this document).  For each message, it wraps it by enciphering the plaintext into a ciphertext and computing a tag over the full sequence of messages. A cryptogram consists of a ciphertext, possible metadata and a tag. For each cryptogram, it unwraps it by deciphering the ciphertext into a plaintext, verifying the tag, and returning the plaintext if the tag is valid. A message can also consist of metadata alone and the corresponding cryptogram does not have any ciphertext.

Clearly the authors here use ciphertext and cryptogram in different senses.  The last sentence tells us that in their usage, there is such a thing as a cryptogram without any ciphertext.
I certainly don't mean to imply that this is by any means an universally accepted usage, however.  In many fields, different authors often use slightly different definitions of the same terms.  The best advice is to always try to discern the authors' meaning in the context they use the terms, and not to try to impose some external definition they might not be heeding.
So perhaps counterintuitively, the answer is "yes" to both of your questions:

Is there any meaningful difference between those terms? Or can they be used interchangeably?

There are many contexts, perhaps even most, where the choice between those two words doesn't matter.  And a few contexts where it does, like the Keyak specification.


How to restore document from records center (not inplace!) in SharePoint 2013 server?

Question: How to restore document from records center (not inplace!) in SharePoint 13 server?
Answer: I am not sure in which event you trying to perform a recovery.There are couple of ways you can do this.

If a document is updated with the latest version, you can go back and restore the previous version
if document is deleted then check the RecycleBin for recovery.
if document is completely gone from site then you need the backup of the content database or site collection backup. You have to restore that in different farm and then copy the required data.


How do I solve the "Unfortunately, System UI has stopped." on Gionee S6 Pro?

Question: I seem to be getting the error "Unfortunately, System UI has stopped." on my Gionee S6 Pro. I have tried wiping cache partition via recovery with no progress. The OS is Marshmallow and UI is Amigo. The touch screen is unresponsive, but I can press the close button after error pops up. Any help would be appreciated. Thanks in advanced!
Comment: Seems issue is with all Gionee S6 models
Answer: the issue is with all gionee S6 model. The best way out of this is to do a factory reset. But u may loose ur files on ur storage.
Answer: The stock  launcher for this model seems  buggy, and apparently there is no fix at the moment.
To solve your problem, try  installing a third-party launcher such as Nova Launcher, Google Now launcher or any other launcher...


In Lua, how can I check if a buffer exists on disk?

Question: I use Neotree on Neovim, and have mapped a key to open the file browser which is supposed to:

open the file browser pointing to the current file
if there is no filename, open the file browser at the current working dir.

It works well except in the case that the buffer has a filename, but that file does not exist, e.g. if you start nvim with the name of a file you intend to create but have not yet saved.
Here's my existing code:
local d = vim.fn.getreg('%')
if (d == '') then d = vim.fn.getcwd(); end
vim.cmd("Neotree reveal_force_cwd " .. vim.fn.fnameescape(d))

In the failing case the % reg is not empty, but it has no file associated with it.
Is there a vim built-in that knows this? or a way to check for the existence of the file?
Comment: I think the Vim function is `filereadable()`
Answer: This seems to work
local d = vim.fn.getreg('%')
if (d == '') then
  d = vim.fn.getcwd();
else
  local f = io.open(d, "r") -- Attempt to open the file
  if (f) then
    f.close(f)              -- Close file if we opened it ok
  else
    d = vim.fn.getcwd()     -- Could not open file, use cwd
  end
end
vim.cmd("Neotree reveal_force_cwd " .. vim.fn.fnameescape(d))


Do double sided GPIO headers exist?

Question: I'm trying to attach two peripherals to a Pi Zero (no pin conflicts as far as I am aware), and I'd like to attach one peripheral to the front of the board and one to the back. Is there such a thing as a double sided GPIO header with pins pointing in both directions? I tried doing this myself with pins taken from a normal GPIO hammer header and it didn't go very well as the pins weren't long enough and I couldn't get the iron in between the pins properly.
Answer: You might be interested in Stacking headers (eg: https://www.adafruit.com/product/85)
Several boards all with stacking headers can be connected on top of each other, including to a breadboard at the bottom of the stack too.
Photo example to illustrate, just an arbitrary google images result:
Answer: Sure, longer pins do exist:

An alternative is to have male pins on one side and female pins on the other:

Searching for "GPIO 2x20" in your favorite shopping site should give you similar results.
In both cases, you may need an iron which is thin enough to go between the pins to make sure the solder flows evenly around each pin.
Answer: You can get extended headers - I use these on my Pico so it plugs into a breadboard but still has accessible pins.
NOTE this will not let you use 2 HATs (as the pins would be inverted).
The normal solution is to use extended headers on the HAT.

Do double sided GPIO headers exist?


Loading Raster and vector data In MapGuide using Maestro

Question: I am new to Mapguide , working on it for my summer Internship.I have Installed it perfectly.
Now the task is to load vector data and Raster data in map Guide (mainly have to load *.shp files and *.tif files). I have find not much resource that provide exact steps. Also I don't know where to put data files ? In Repository or somewhere else ? How to link these file ?
Can any one help me in this?
Answer: You can still use tiff and shp. How you use them in mapguide is via connectors/provider or data source.
This step should be quite well documented. Please refer to the manual for either maestro or mapguide.
By the way, here's a good start:
http://trac.osgeo.org/mapguide/wiki/maestro/UserGuides/FileFeatureSource
Good luck!


Storing film in the fridge with air ionizer?

Question: I have several 135 and super8 unexposed film rolls and I'd like to store them in the fridge. However, my fridge has that air ionizer (which should keep food fresh for longer time). Should this ionizer actually damage the film itself?
Thanks.
Comment: I assume they are in air-tight containers, right?  So the ionizer won't matter as there will be no air exchange with them.  Are they?
Comment: @Linwood yes, the 35mm films are in those airtight round plastic cans with lid, super8 cartridges are in plastic foil. So generally as long as they are airtight sealed they should be fine? I had to ask this question because I don't know how strong the ionization in the fridge is, what kind and if film is sensitive to this particular kind.
Comment: I think the answer given is correct in conclusion, though the first paragraph is pretty disconnected from the conclusion, but if the containers are air tight, the ions in the air won't get to the film.  It's highly unlikely if they did it would be an issue. It's more like the slightly charged air you get on a thunder filled nights, a bit more ions in the air, not ionizing radiation (i.e. radiation which can ionize material it strikes) like an x-ray machine.
Answer: Air is a mix of nitrogen and oxygen and other gasses. It is ionized by a device it outputs high voltage. Now film is sensitive to light and ionizing radiation. Could the ionizing device in the refrigerator output X-ray etc.? Possible but unlikely.
Film is a perishable, it has a shelf life.  We can prolong shelf life by refrigeration and by protecting the film from humid conditions. Boxed film has a moisture barrier envelop. The film inside is at near zero as to humidity. Once the packaging is compromised, the shelf life decreases.
I think you can safely store film in refrigerators with an ionizing device.


PMDC motor: how much is voltage reduced if the resistance produced by commutation system is eliminated?

Question: I have made a PMDC motor. The resistance of the coils is 0.25 ohms. But the commutation system is very resistant. It adds more 0.85 ohms to the armature resistance. So, the total resistance becomes 1.1 ohms through the commutation system.
The motor needs 14.80 volts and 5.75 amperes to work properly, using the same commutation system.
If the commutation system is replaced by electronic sensors, would the over resistance added by the commutation be eliminated? If so, what amount of lesser voltage would be needed? my calculation (according to ohm law) concludes that this motor needs only 3.363 volts if the over resistance caused by the commutation system is removed. As:
Total resistance/ coils resistance= 1.10/0.25=4.4;
Present voltage/4.4=14.8/4.4= 3.363 volts.
Is this calculation wrong?
Comment: How will you connect to the rotor/armature if not using a commutator and how much resistance will this have? PMDC motors usually have a spinning magnet to avoid such problems.
Answer: You haven't allowed for the back EMF in the voltage calculation.
There are 3 sources of voltage drop opposing the supplied voltage :

I (5.75A) * R (0.25 ohms) in the winding, = 1.43V.
I (5.75A) * R (0.85 ohms) in the commutator/brush, = 4.88V.
Back EMF which is speed dependent, and currently 14.8 - 4.88 - 1.43 = 8.49V

Eliminating the commutator losses (and maintaining the same speed and torque) reduces the voltage requirement by 4.88V, giving 9.92V.
Comment: Thank you very much for your answer. Your answer leads me to the right calculation.
Answer: Assuming you can overcome (with zero resistance using slip rings or some other magical method) the 0.85 ohm resistance in the commutation, this reduces the effective motor resistance from: -
$$\dfrac{V}{I} = \dfrac{14.80}{5.75} = 2.574\Omega$$
To....
2.574 ohms - 0.85 ohms = 1.724 ohms
But, because you will still need to have the same current flow of 5.75 amps, the terminal voltage required to deliver this is: 9.913 volts
If your proposed "new" method to eradicate commutation results in less torque required to turn the motor at operating speed then, the current (5.75 amps) will also reduce a little bit. However, assuming that the real load torque is much bigger than the "friction" torque this won't reduce the 5.75 amps by very much. You might get away with 5 amps for instance and the terminal voltage might become 8.62 volts.
Your calculation failed to recognize the full resistance of the armature/rotor as being 2.574 ohms. This is probably because you forgot that the rotor coil produces a back-emf that appears to increase the stall resistance of the rotor/armature. The stall resistance of the armature/rotor is 0.25 ohms but, when running in the conditions you list it will be 1.724 ohms.
Comment: I am grateful to you for your detailed answer. It will help me a lot.


Sharepoint add time in top navigation bar using js

Question: Hi anyone knows how to add time near search bar please refer to red arrow in image.
Answer: In classic SharePoint pages we could use the ContentEditor or ScriptEditor web parts to inject JavaScript to do this type of DOM manipulation. This worked because the DOM of classic pages rarely changed.
However, the same is not true of modern SharePoint pages. The DOM of these pages changes regularly so any manipulation using element Ids or CSS class names will eventually break. You can do some user interface customizations on specific areas of a modern page using the SharePoint Framework, but adding the time in the areas you indicated is not one of them.
I think your best option to add the time to the page would be to put it in a footer which you could add to the page using a SharePoint Framework Application Customizer extension.
Comment: thank you for the info.
Answer: According to my research and testing, unfortunately, we cannot customize the top navigation bar in modern SharePoint sites, it is by default. We can only add link/label in the navigation bar. Thanks for your understanding.

===================================
If the answer is helpful, please click "√" on the left panel of the answer and kindly upvote it.
Comment: Do you have any further questions about this thread? If you have any questions or progress, you can contact me in time.
Answer: You cannot customize office 365 ribbon bar (top most navigation - near search box) to add time.
You have below two options:
Option 1 (Recommended): Use default page placeholders provided by Microsoft in SPFx application customizer to show the time in header/footer.

Follow Microsoft official documentation at: Use page placeholders from Application Customizer
Option 2: Inject custom JS/CSS using SPFx application customizer to show the time in navigation.
You can use SPFx application customizer to inject the custom CSS in SharePoint online modern pages. Check more information at:

How can I include the same JS and CSS files on multiple SharePoint Modern Page?

Note: DOM manipulation & CSS customizations are not recommended by Microsoft and some of your customization may break if Microsoft changes HTML element id/classes in new release updates.


What happens to the visible light that a substance does not reflect on an atomic level?

Question: Let's say we have a blue, opaque material. If white light was incident on that material, the blue light would be absorbed by electrons and the electrons would transition to a higher energy state, and then the electrons would transition back to the original state (ignoring any other states it could drop to) re-emitting that light to make the material appear blue, but what happens to the rest of the light? Is the rest of the light absorbed by molecular bonds and converted into heat?
Comment: A blue material reflects blue radiation and absorbs red etc.. There is no atomic absorption involved in that reflection. In general, a solid is _not_ well described by atomic physics. We need to understand its inter-atomic or molecular structure to describe interaction with light.
Comment: The energy levels in atoms are nice and discrete, but when two atoms with the same energy levels interact they influence each other. Each pair of degenerate, i.e. equal energy levels splits into two levels of unequal energy. The discrete spectrum now looks a lot more complicated. Three, four, five etc. atoms will split these levels further and further. By the time we have a macroscopic solid, these "forests" of energy levels have become continuous energy bands. It becomes meaningless to talk about atomic states. The solid behaves in a different and much more complex way than its atoms.
Comment: Interesting, so the electrons in the atoms/molecules of a blue material  interact with the photons, but they don't transition to another energy level and just essentially 'reject' the photon and re-emit it? Is this due to the photon energy not corresponding to any available energy levels for the electrons?
Comment: @CuriousOne what you say is correct, but in the OP's comment he or she makes no mention of  atoms.   That comment is correct:  the blue light is reflected because there are no energy levels to absorb it.
Comment: @garyp: It's in the title and the OP asked a similar question before. I am merely trying to make him think about the problem in a wider context than atomic physics.
Answer: I'm not sure what you mean by "the rest of the blue light." Basically three things can happen when low energy light passes though matter.

Absorption and reemission. The light excites a dispersion free mode, like your electronic energy state example, in that case the light will be reemitted at the same wavelength most often. You can work out the exact distribution with the Bohr-Dirac model (bohr model with relativistic corrections).
Absorption and dispersion. Light can excite phonon modes, those will disperse and heat the object up.
Finally, light can pass through the material and not interact with the object at all.
Comment: you have skipped mentioning elastic scattering, which is not re emission  .
Comment: see http://quantummechanics.ucsd.edu/ph130a/130_notes/node43.html
Comment: Interesting, Thank you for your comment Anna, I will update the answer when I have a more clear picture. I have always been trained to believe light can not change directions without being absorbed and reemitted... a consequence of relativity. If one wants to compute the angular distribution of final state light after bombarding a material with photons, is not true that we sum diagrams which have the light being absorbed along with diagrams in which the light is not?

That is to say, what are the observable and computational differences between absorption+reemission vs. elastic scattering?
Comment: absorption and reemission presuppose existing  quantized bound energy levels. Elastic scattering is off the  spill over field of the whole atom/molecule/ lattice


Can a village be underground?

Question: Can I build a valid village (actually an iron golem farm) completely underground (no skylight access above)? If no, what is the closest solution to have an iron golem farm underground?
Comment: At one point, I know, each house had to have at least one space open to the sky.
Comment: @SaintWacko, on the top of the door block?
Comment: No, but one time it noticed a butcher shop was underground. I noticed it's roof. Turns out it was at a trench or ravine.
Answer: Not completely, no. You will need some sort of air shaft.
Villages, in Minecraft, are just a collection of doors that meet the condition of having more spaces on one side exposed to sunlight (This page on the Minecraft Wiki goes into the details). This means that a village/Iron Golem farm without any skylights won't work, as none of the doors placed will count as Village houses. The closest you can come will involve either open shafts, or else glass or something similar in the ceiling.
Comment: The link in question doesn't say anything about sunlight.  Is it possible that the requirements have changed and an underground village may now be possible?
Answer: If you build the village completely from scratch it's a possibility. My villagers are still alive after a week of starting an underground village. You'll need a couple trees (learn via YouTube), beds for them to sleep (yes they still go by surface time) and plenty of light so zombies don't kill them. As for a golem I have yet to make one in mine so as I said it is a possibility. Now mojang generating one fully underground is unlikely but possible though the closest I've seen was the ravine, landbridge, or a village in the opening of a cave. I wish you luck on your building be creative and if you do build from scratch try making it as closely resembled as their home on the surface. A cat spawned in mine once the villagers got comfortable.
Answer: No, not without a glitch occurring. I was once playing minecraft on my Xbox. A village had spawned really close to a trench so some houses and a farm spawned there. A stronghold was right next to it. You'd be surprised how many villagers had wandered as deep into there as they were without getting killed by zombies.

Can a village be underground?