Interpretation: probability form probability amplitude (free particle)

Question: If you compute the probability amplitude of a free 1D non-relativistic particle with mass $m$, located at position $x_0$ at time $t_0$, for beeing detected at some other point $x_N$ at time $t_N$ you will find it to be given by
$$
  \mathcal{M} = \left\langle x_N \right| \text{e}^{-\frac{\text{i}}{\hbar} \frac{P^2}{2m}(t_N-t_0)}\left| x_0\right\rangle =\left(\frac{m}{2\pi\text{i}\hbar\ (t_N-t_0)}\right)^{1/2} \text{e}^{\frac{\text{i}}{\hbar}\frac{m}{2}\frac{(x_N-x_0)^2}{t_N-t_0}}
$$
Now, if I compute the corresponding probability(density) according to
$$
  P = \left|\mathcal{M}\right|^2 = \mathcal{M} \mathcal{M}^* = \frac{m}{2\pi\hbar\ (t_N-t_0)}
$$
it somehow strikes me that it does not depend on the distance $(x_N-x_0)$ at all. Does this mean, that the probability of detecting the particle is the SAME everywhere? I expected something like the initial (i.e. $t_N \rightarrow t_0$) delta function "melting away" like a Gaussian wave packet... Can anyone tell me what the correct interpretation of $P$ should be?
Comment: You can describe Gaussian wave-packet centered at $r_0$ with position variance $\sigma$, if you begin with initial condition $\psi_0(x_0,t_0) = \frac{1}{\sqrt{\sqrt{2\pi}\sigma}} e^{-\frac{(x_0-r_0)^2}{4\sigma^2}}$. You can then find its time evolution by calculating the integral below.
Answer:
Does this mean, that the probability of detecting the particle it the SAME everywhere?

No, it does not. This is quite a common mistake, stemming from the idea that the Green function $\mathcal{M}$ can be used in the role of the $\psi$ function of free particle with the Born interpretation of $|\psi|^2$ as probability density. But that is not possible, since $\mathcal{M}$ is not normalizable.
The quantity $\mathcal{M}$ is simply the Green function of the time-dependent Schroedinger equation for free particle. It can be used to express $\psi$ function of the particle at time $t$ as
$$
\psi(x,t) = \int \mathcal{M}(x,t;x_0, t_0) \psi_0(x_0,t_0) dx_0
$$
where $\psi_0(x_0,t_0)$ is normalized initial $\psi$ function at time $t_0$.
Comment: Is it then also invalid to take $\psi$ in the integral to be the position operator eigenfunction?
Comment: Position operator does not have normalizable eigenfunction. Delta distribution is often called its eigenfunction, but it is not normalizable. We can plug it in the integral, but the resulting $\psi$ won't be normalizable either.
Comment: Does that imply, that it is really IMPOSSIBLE for a particle to be in a position operator eigenstate?
Comment: It is impossible if we work with the Born interpretation of $|\psi|^2$ as probability distribution.If we dropped this interpretation and understood $\psi$ in some other way, it could be possible for the delta distributions to play the same role as normalizable $\psi$'s. Or we could introduce new object, $\sqrt{\delta}$, to play the role of normalizable position eigenfunctions. But none of these seem to lead to much new understanding. One way to reconcile with this situation is to drop the idea that measurement of positions reduces the $\psi$ functions to eigenfunction of the operator $\hat x$.
Comment: Thank you very much for elucidating these issues! Do you happen to have any literature suggestions regarding this topic? I'd be particularly interested in seeing up to what level of mathematical rigor it is possible to introduce "normalizable position eigenstates" and what the implications of such an approach would be.
Comment: In ordinary quantum theory, I do not know of of any good reference. In the quantum field theory, people talk about discretization much more - instead of continuous space, the theory is formulated for discrete lattice and the spacing is sent to zero only towards the end of the calculation. One important implication of this seems to be that once the space is discretized, it is hard to make the theory conform to the principle of relativity (lattice is not symmetric with respect to rotations, change of frame velocity brings length contractions of lattice etc.)
Answer: The Feynman propagator/kernel/amplitude is, as OP writes,
$$ \langle x_f ,t_f | x_i ,t_i \rangle~=~ \sqrt{\frac{m}{2\pi i\hbar} \frac{1}{\Delta t}} \exp\left[ \frac{im}{2\hbar}\frac{(\Delta x)^2}{\Delta t}\right],  \tag{1}$$
where $\Delta x:=x_f-x_i$ and $\Delta t:=t_f-t_i > 0$. It is implicitly understood in eq. (1), that one should perform the Feynman $i\epsilon$ prescription. More precisely one should substitute $\Delta t\to\Delta t-i\epsilon$, i.e. the $\Delta t\in\mathbb{C}$ in eq. (1) is actually situated just below the real axis in the complex $\Delta t$ plane. This $i\epsilon$ prescription ensures that the propagator (1) becomes a Dirac delta distribution in the short time limit:
$$  \langle x_f ,t_f | x_i ,t_i \rangle ~\longrightarrow~\delta(\Delta x) \quad \text{for} \quad  \Delta t \to 0^{+}.\tag{2}$$
As explained in Ref. 1 there is no absolute notion of probability since the position space is non-compact, but there is a relative notion of probability. The relative probability distribution in position space becomes uniform
$$\begin{align}  P(x_f,t_f;x_i,t_i)~=~&|\langle x_f ,t_f | x_i ,t_i \rangle|^2\cr
~=~&\frac{m}{2\pi \hbar} \frac{1}{\sqrt{(\Delta t)^2+\epsilon^2}}\exp\left[ -\frac{m\epsilon}{\hbar}\left(\frac{\Delta x}{\Delta t}\right)^2\right]\cr
   \longrightarrow&~ \frac{m}{2\pi \hbar} \frac{1}{\Delta t}\quad \text{for} \quad  \epsilon \to 0^{+}.\end{align}\tag{3}$$
Physically, this may be understood as that the corresponding relative probability distribution in momentum space is uniform as well. Phrased differently, a position eigenstate is a superposition of all momentum eigenstates, and it turns out that the particle can be near or far away with the same probability density.
For more on normalization of the path integral, see e.g. this Phys.SE post and links therein.
References:

R.P. Feynman and A.R. Hibbs, Quantum Mechanics and Path Integrals, 1965, Problem 3.1.


Is it safe to heat a sauce pan containing a glass bowl over an electric cooktop?

Question: I screenshot 0:16. Won't the heat damage, shatter or explode the glass bowl? I'm not affiliated with that YouTube channel "missevabakes".
Comment: maybe the heat under the pan is turned off just when the water became hot enough?
Answer: I don't think there's enough clarity in the video to answer definitively. So, a couple of critical points:

The glass bowl should be floating in the water. Otherwise, it could contact a much higher temperature at the bottom of the pan than whatever temperature the water is at.
The water should be heated with the glass bowl in it already. If the water is already very hot and an ice-cold bowl were dropped in it, the glass could crack or break.

Of course, different types of glass have different resistance to thermal shock. But regardless of the type of glass, treat it gently and with respect. Just because it's designed to withstand abuse, doesn't mean there's any good reason to subject it to abuse, and plenty of good reason to use reasonable precautions. :)
Answer: Unless you have a very cheap or extremely cold (think -30 c) glass container, there's absolutely no problem. Even with an extremely cold container, I doubt you'd manage to get it to shatter.
The water will heat progressively and so will the glass container. I melted chocolate this way in various container including glass, never had a problem.
Comment: Perfect answer.  Look up bain-marie...going back before thermodynamics were understood we used this method.
Comment: If the glass bowl was contacting the bottom of the pan directly it could be a problem @Jeffrey.


Can you soft reset for shiny legendaries before the Elite Four?

Question: I know that the weather trio and supposedly Deoxys are shiny locked, but I'm currently SRing for shiny Mesprit, before the Elite Four. However I'm nearing 3000 SRs now (a total of 4 days work considering I have college in between) and I was wondering if I'm wasting my time. I don't just want to give up after spending so long on it though, so if someone could find out if you can get shiny legendaries before facing the Elite Four for the first time that'd be great. c:
Answer: I don't know why you think that beating the Elite Four could change the shiny form of Mesprit. The only shiny locked are Groudon, Kyogre, Rayquaza and Deoxys, as you said.
Anyway it's sure that Mesprit can be found shiny, I think it doesn't matter when you catch it.
Comment: Alright. I thought it wouldn't make any sense, it's just taking me a long time :') thank you for answering.


What kinds of gloves are best for handling thorny rose bushes?

Question: I have a couple of rose bushes in my new house and the thorns in the bush (there are a lot of them!) go right through my current gardening gloves, and they hurt. what kind of gloves are available that will prevent rose bushes from stabbing my hands?
Comment: What kind of gloves are you currently using? just the soft cloth garden gloves?
Comment: yea I'm not surprised - they wouldn't protect against my cacti. I'd suggest some good leather gloves along the lines that @waxeagle or myself have suggested.
Comment: @waxeagle - I am using cloth gloves with a rubbery kind of coating - kind of like these - http://www.biofloris.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/m/3/m300-gloves.jpg
Comment: good deal, I almost suggested some of those before I thought better of it.
Comment: @Moe: These kind of gloves are good for soil and general dirt. They don't don't take thorns very well.
Answer: I don't have much experience with roses (just planted my first bush this year), but it seems to me that you have two options when dealing with thorns.
Good leather gloves, or consider a specialized product like garden armor. Leather gloves are harder to penetrate.I have not used garden armor, but they appear specifically designed to do exactly what you want them to.
Comment: I got leather gloves, I didn't think they would be good enough, and I was expecting to need to return them - but they did the job.
Answer: For a different idea...
I hate buying gloves and having them fall apart all the time. (I'm rough on gloves. Even the expensive ones split apart quickly when you're moving wood, rocks, or doing a lot of digging.)
Call me a cheapskate, but I buy the cheapest gloves I can find (e.g. these US$2 work gloves). Then I wrap a layer or two of duct tape (heavy duty -- the good stuff) around the fingers, and a layer or two around the palms. Don't wrap too tight or they'll be uncomfortable (it's best to have a helper wrap your gloves while you're wearing them).
They're durable, easy to repair, and provide good protection against thorns. As winwaed says in his answer, there is a tradeoff between comfort and protection. I have a pair with only finger reinforcement that I use for shoveling or moving wood or rocks. If I'm going to pull out a bunch of blackberries, I'll use something with palm reinforcement.
You might use an extra layer of tape if you find the thorns penetrating a single layer.
Three cheers for duct tape!
Comment: Ah, Duck tape. Is there nothing it can't do?
Comment: @Michael: It can do everything EXCEPT repair ducts!
Comment: great idea! I'll have to try that
Answer: There is going to be a trade off between comfort and thorn resistance. At the thin end (which you are probably using) are the thinner gloves. These would include fashion gloves ("ladies gardening gloves"), and the cheap barely-a-whole-hand glove which are great for lifting timber, bags of gravel, etc. but give little protection for spines, nails, etc.
Next up there are heavy duty gardening gloves which are made of a thicker suede-like/leather material. Usually these are longer and give some wrist protection. They cost more - perhaps as much as 5x the price of the cheap ones. These might be sufficient - I find they're good enough for the better behaved cacti.
The full solution (which I haven't tried) would be to go for proper welding gloves. These are thick leather affairs. They're not going to be as comfortable - possibly oppressively so in a hot, humid climate; but they'll protect against a lot. Their thickness is really for thermal protection but it is a thick dense material rather than oven glove "fluff".
Although I've never handled a pair, I understand falconry gloves are similar to welding gloves - clearly here the protection is against spikey things (talons and beaks) rather than heat.
Comment: It would be totally awesome to weld with one hand while holding a falcon with the other - and you would only need one pair of gloves!
Comment: I wouldn't use welding gloves for gardening. I loose a lot of dexterity when I wear mine - but then again they were just about the cheapest ones out there. You might be on to something with the falconry gloves though.
Comment: Yes they're not the most flexible, but as I say I think there's going to be a tradeoff between comfort and thorn protection.
Answer: I'd recommend something like a puncture resistent glove that's much stronger than leather (the page says 4 times). This is also ergonomically designed, so you won't have much discomfort.
These are most often bought by people who cut their fingers on the kitchen slicers. So while it's not really a "gardening glove", I see no reason to not use it as one. Also, it's pretty inexpensive at $14.
Answer: I kept bees a long time ago and I often wish I'd kept the kit because I miss those long gloves.
Beekeepers need protection while also needing a glove which allows careful and precise hand movements. Typically their gloves go right up the arm.

Beware, though, beekeeping kit isn't cheap.
Comment: I definitely AM looking for something cheap ;-)
Answer: The gloves I use don't really protect from thorns all that well, but I find that if you handle roses by grabbing them right near the flower itself, you don't encounter many thorns.
Answer: i've had good luck with insulated leather gloves and my hands don't feel especially uncomfortable on a 100° day. barberry thorns are thinner and impossible to avoid. they go through the leather occasionally; and once it's happened, it will happen more frequently in the same spot. 'thought about adding some duct tape to the grip areas......un-insulated are no good for thorns; insulated suede are okay but not as good. i will not use rubber or plastic dipped for thorn-work again. that was painful! doing some research, i now see why. they are "cut" or "slash" resistant because they're woven with resistant materials; but thorns will travel in-between the weaves. the coating itself offers little protection,it seems........it may help to note that rose thorns point inward -wild (invasive)multi-flora even more so; so if you can avoid sticking your arm in you may avoid getting sliced. i often use a short pole-pruner to clip toward the base of the stem, (such as this 5' one: http://cdnll.gardenersedge.com/images/500/9234_1.jpg )then pull it out by the tip of the branch. i may have to make a few cuts because of cross-branches, but it's still easier than going against the direction of the thorns.(& safer)......i am considering trying these: http://www.magidglove.com/assets/item/hero/TRX550_HERO3.jpg


South Korean Visa for Research Conference

Question: I am an Indian passport holder, living in the United States. I have to travel to South Korea for a research conference. I want to know how can I apply for a visa for South Korea from the US. I tried searching for information here (http://www.mofa.go.kr/ENG/visa/application/index.jsp?menu=m_40_10), however most of the links are not opening and throwing security error messages. Thanks.
Answer: When looking up for visa issuance, it makes sense to search for Embassy/Consulate in your country. This is because the visa issuance procedure is a very low level detail, and often has country-specific requirements. MOFA web site usually covers high level things falling under "International affairs".
Most countries have more than one Consulate in the USA, and each Consulate usually only accepts applications from certain states. Here are Republic of Korea consular missions in the USA explaining which state they cover. They only list phones and no web sites - google them.
And for example, visa issuance page for Atlanta Consulate General - other consulates will very likely have the same procedure, application form and fees.


Share iCloud Family Calendar with Outlook

Question: My wife and I use the iCloud shared Family calendar for scheduling family events. I would like to be able to view this calendar from my work Outlook account. Is there some way to share the calendar with non-Apple calendar applications?
Comment: Can you provide a link? There doesn't appear to be a current Apple product by that name?
Answer: First, I am assuming by "Outlook" you mean the Outlook email client application and not an @outlook.com email account. In other words, your work computer uses the Exchange/Outlook system for emails, calendar, and so on.
If so - and assuming your IT department would permit this - you could try the iCloud Control Panel on your work computer. This add-in for Outlook will sync the Outlook email app with your iCloud email, calendar, and contacts - including your Family Calendar.
Instructions can be found on Apple's website. Good luck!


The remote server returned an error: (403) Forbidden. upon clicking Personalize button of any component

Question: I am getting the below error on clicking Personalize button of any component in production sitecore instance which is working fine in other environments. We are using Sitecore 9 and SXA. I have attached the screenshot too. Not able to find the reason.
Comment: can you check connection strings to reporting database?
Comment: I doubt this is SXA related...
Comment: There is no entry for reporting database in connection strings. Instead, there is an entry for reporting.apikey
Answer: This happens when reporting api keys are not configured properly. It should be configured both in CM instance and reporting server.
If the authentication keys do not match, the server responds with a 403 (Forbidden) status code.
Please do read below links for more details:-
Configure security keys on servers in a scaled environment https://doc.sitecore.net/sitecore_experience_platform/setting_up_and_maintaining/configuring_servers/configuring_servers/configure_security_keys_on_servers_in_a_scaled_environment
Configure a Reporting Service server
https://doc.sitecore.net/developers/server-role-configuration-reference/core-roles/reporting-service/index.html
Configure reporting API key
https://doc.sitecore.net/developers/server-role-configuration-reference/core-roles/reporting-service/configure-reporting-api-key.html
Comment: Our site is hosted in Azure (PaaS) and there is no entry for reporting database in connectionstrings.config file. Instead, there is an entry for reporting.apikey. Please let me know whether the problem is due to not having entry related to reporting database. If not, how can i validate the api keys in azure model
Comment: @ManideepYechuri - We are facing the same issue. Did you find any solution to the problem? if yes please share.


Code families in McEliece cryptosytem

Question: What are the families of codes frequently used in McEliece cryptosystem or its variants? I know that binary Goppa codes were used in the original system but many codes with efficient decoding algorithm can be used. Are there any other requirements on the code or generator matrix for that matter? I don't care about parameters used, just the names of families like Goppa, Hamming , Reed Solomon etc. is enough.
Comment: From what I know the binary goppa codes stood the test of time best...
Answer: The modern approach is still to use binary Goppa codes.  See, e.g., McBits from 2013:

Daniel J. Bernstein, Tung Chou, Peter Schwabe. "McBits: fast constant-time code-based cryptography." Pages 250–272 in Cryptographic hardware and embedded systems—CHES 2013—15th international workshop, Santa Barbara, CA, USA, August 20–23, 2013, proceedings, edited by Guido Bertoni, Jean-Sébastien Coron. Lecture Notes in Computer Science 8086, Springer, 2013. ISBN 978-3-642-40348-4.

https://binary.cr.yp.to/mcbits-20130616.pdf
Other proposals, such as Niederreiter's using generalized Reed–Solomon codes, have been broken:

V.M. Sidelnikov, S.O. Shestakov. "On insecurity of cryptosystems based on generalized Reed–Solomon codes." Discrete Mathematics and Applications, 2(4), pp. 439–444, 1992.

https://doi.org/10.1515/dma.19126.96.36.1999 (paywalled, sorry!)
Comment: are there any other proposals for use of other codes? I get that Goppa codes are the ones that are mostly used but the  proof for security of system doesn't involve much restrictions on structure of code. Also when one referral to 'variants' of McEliece in what sense these variants. I thought these variations are in terms of underlying code.
Comment: I'm not aware of proposals to use other codes.  They would have to demonstrate better performance for the same security to be useful.  I don't follow what you're asking about variants—you used the term 'variant' in your original message, and I didn't echo it.  You could vary the code, as in McEliece over GRS codes instead of McEliece over Goppa codes, or you could vary the construction, as in the [Niederreiter](https://en.wikipedia.org/wiki/Niederreiter_cryptosystem) cryptosystem, which is like McEliece backwards.
Comment: @Root: A preprint proposing McEliece over QC-MDPC (quasi-cyclic moderate-density parity-check) codes, for ephemeral key exchange only, allegedly thwarting all existing attacks on such codes, recently appeared on the IACR archive: [Paulo S.L.M. Barreto, Shay Gueron, Tim Gueneysu, Rafel Misoczki, Edoardo Persichetti, Nicolas Sendrier, and Jean-Pierre Tillich, 'CAKE: Code-based Algorithm for Key Encapsulation', IACR Cryptology ePrint Archive: Report 2017/757](https://eprint.iacr.org/2017/757).  Earlier proposals based on QC-MDPC have been broken, as is this one for non-ephemeral public key use.
Comment: just a follow-up question :  the paper doesn't mention any particular decoder. Is there a standard decoder for such codes? Also is the new system quantum secure? The original McEliece is shown as secure under quantum attacks.

Code families in McEliece cryptosytem


Can I use southeast asian fish sauce as a marinade?

Question: I have been using Southeast Asian fish sauce ( its Vietnamese variant called "nước mắm" to be precise ) to marinade meat which I would then fry. From the narrow observation I made though the Vietnamese seem to use it solely to dip the food in it. Is my usage really that unusual?
Comment: Welcome! This site is about cooking, not health (see the [faq]), so I removed that part of your question. What remains seems like a pretty trivial question, so feel free to edit further if it's not all you meant to ask!
Comment: @Jefromi Hi. I understand the principle, but my question was more about if it is not the case that such frying would cause some chemical reaction that would make such practice a bad idea, not about classic concern - how healthy my dish would be. :)
Comment: Ah, I see. That didn't really occur to me, because in general, foods that are made out of normal ingredients (meat or plants) do not become unsafe when you cook them. I don't see why fish sauce would be an exception, but you're welcome to edit a food safety question back in if you're concerned!
Comment: My mother (vietnamese) used fish sauce on pretty much everything in the kitchen. It can sub in for salt in a lot of dishes and it works well as a marinade. I like to season my fried eggs with tons of it (with a bit of sugar to even it out).
Answer: No, it's not unusual at all. See this page from Vietnamese-American cooks for examples where nuoc-mam is used to marinate chicken, or just type

nuoc mam marinade

in Google :)
There are a lot of examples, including fish, chicken, beef, or even mango marinated (as well as dipped, of course) with nuoc-mam (and most of the time lemongrass), and a fair share of them are recipes by 'natives' from South-East Asia, not only fusion food addicts (even if you can be both!).
Some salads like goi tom or goi ga also involve nuoc mam marinade.
Comment: Thanks for the great answer! Especially for those great examples :)
Comment: You're welcome! I added a few links now that I am allowed post more than two. Enjoy!
Answer:
Verb - marinate = to pickle in brine, sea water. Marine.
Noun - marinade = the liquid used as medium to marinate.

Wikipedia on "Fish Sauce":

Fish sauce is an amber-colored liquid extracted from the fermentation of fish with sea salt.

From the definition/etymology of the word of "marinate" - - -> of course, you can. It's your kitchen and your preferences for flavour.
I am sure that marinating only flavours the outer layers of meat and you should cut gashes into the meat to allow the marinade to penetrate.
Rather, your question should be,

how do I marinate with Vietnamese/Thai fish sauce?

I think, in fact, you could even ask the question,

How do I marinate meat with Australian Vegemite or British Marmite?

I think to preserve and complement the fishy fragrance (most people would prefer to call it fishy odour),

the marinade is retained to be part of the gravy.
you should have garlic powder and chopped scallions mixed in the marinade (the fish sauce).
little bit of black vinegar
I did try mixing in curry powder, cinnamon.

And then the marination graduates into a marinating/poaching process on the same pan by turning the temperature up. What I am describing is a form of poaching which I do at low temp grilling in an enclosed oven.
I marinate at 100F for a couple of hours and then turning up the temperature to poach at 200 F over another couple of hours using various appendices/apparatus to elevate the meat (chicken wings/quarters) to as close to the oven elements as possible without touching them. About an inch of clearance.
And finally turning the temperature up to 350F for 30 minutes to "attempt" to achieve the occasionally surprisingly crispy skin
Turning the meat over at opportune times. The slow grilling can produce pretty amazing crisp on the skin. (However, there was once when the salmon became dry and fibrous after leaving it in there for too long.)
I am sure there is a lot of room for improvement in my culinary timing skills. And I've only tried poaching poultry and salmon. I did destroy a few pretty herring by trying out the same process. And turkey wings/quarters wouldn't even get cooked or amenable to absorbing any marinade under the same process.


Leave-one-out cross-validation for MLR

Question: I am doing cross-validation using the leave-one-out cross-validation method (total 10 runs). I have predicted $\hat{y}$ and observed $y$ from all the runs. I have applied the following equation to calculate $R^2$. Can anyone please confirm whether I am doing right? I am confused because the $R^2$ value appeared negative.
\begin{align}
SSE&=∑(y-\hat{y})^2  \\
SST&=∑(y–\bar{y})^2    \\
R^2&=1-(SSE/SST)
\end{align}
(N.b., $\bar{y}=$ is the average of $y$.)
Comment: SST usually stands for total sum of squares, so it better be positive, I don't see where the square is in your formula for SST
Comment: Sorry, I missed it while writing. The R2 value is negative. Would you please tell me how the result can be interpreted? Does it happen often?
Comment: I am confused because of a lack of indexing on your sums. Should y^ be y^_i? If what you are doing is some sort of nonlinear regression, what a negative value for the formula you propose for R^2 is saying here is that a flat line through the mean is effectively a better model than the one you have for y^?
Answer: The wikipedia page for R^2 values talks about negative values.
http://en.wikipedia.org/wiki/Coefficient_of_determination
It basically suggests what I was getting at in my comment. The mean of the data is providing a better fit than your (presumably more complicated) model is. It may be time to go back to the drawing board and think about a different model. Either that or there is a bug in coding up your model.

Leave-one-out cross-validation for MLR


Is that worth to take the latest CPU to mine Ethereum?

Question: I've been thinking that it's actually worth, but I'm pretty sure I'm missing something there, as I looked into the last AMD 8x R9 390, that has a 250MH/s rate, which is pretty impressive, while it only costs 300€. So, shall I go for this GPU ?
Answer: for the cpu mining i suggest you to read this post :
Is CPU mining even worth the Ether?
however before you buy a gpu to mine ethers consider to get an estimation about the Profitability , there is a lot of tool to do so i suggest you to try : https://badmofo.github.io/ethereum-mining-calculator/ or  https://etherscan.io/ether-mining-calculator
also you could get an idea about the hasrate comparaison between the GPUs used to mine ethereum : http://www.mininghwcomparison.com/list/index.php?brand=amd
i made the calculation i've found that you will get about 29(>300$) monthly.
Comment: Well thanks, I needed that confirmation because I found 2 different hashrates for the same GPU for ethereum mining, I guess I made a mistake somewhere.
Comment: Could you confirm that the MSI 8x R9 390 hashrate please ? I'm only getting this number at  http://www.mininghwcomparison.com, otherwise everybody's saying it's about 30MH/s
Comment: you mentionned in your question that you card has 250MH from where you got this info?
Comment: From http://www.mininghwcomparison.com/list/index.php as I mentionned it
Comment: 8x means 8 of those!
Comment: these data are submited by user so there is no way to check unless runing eth with gpu hash rate check


How can I delete Twitter DMs from all my devices?

Question: Is there any way I can delete my Twitter direct messages from all my devices? I tried deleting them from the web, but I can still see them on my phone. I also tried several web services but nothing seems to delete them from every device. Help?
Answer: If you can't see it anymore from the Twitter Web interface, they have been deleted for good.
If by mobile you mean an application, then they're being cached. Your mobile app doesn't know that you deleted them or doesn't have feature to remove them from cache once they have been deleted. If it really bothers you, Clear cache and/or data of your app, and they should go away.
Answer: Out of plain ole curiosity about this topic, our isolated experimental results just confirmed that Bibhas's answer may not be the case at all for public tweets, which probably means DM, too. We would have expected him to be right. However, we used a couple of different delete-all tools over past couple weeks to give 'em time to work in two batches of 3,200 at a time; due to the test account storing less than 6,400 tweets. The tweets appear to be all gone from the web, but not mobile. Cleared cache, cleared data, oldest tweets still there; perhaps 1,000 or so.
Uninstalled Twitter mobile app. reinstalled. Same result.
Used a different Twitter account to see if we could still read mobile app tweets. Yep, no tweets on web, but guesstimate around 10–15% oldest tweets still appear in the mobile app, but only after refresh. When the app first loads it says no tweets. Swipe down to update, and there they are.
Next step is to try from an entirely different phone, in the event that clearing cache and data on mobile Twitter app doesn't really clear cache and data, nor would uninstalling, in this case. Will report back on that shortly.
Observation/inquiry: the remaining tweets are all 2010 and older; is there anyone from Twitter around who might be able to unofficially confirm whether there is something about the way oldest tweets are stored that is responsible for this unexpected persistence?
Comment: Interesting observations. But no, there is nobody from Twitter around; this is a 100% webapp-users site. You may want to remove the inquiry and send it to Twitter instead.


Buying bitcoins in Zimbabwe

Question: I'd like to use US dollars to buy bitcoins in Zimbabwe. Does anyone know how I could do this or how to find bitcoin sellers in Zimbabwe?
Answer: You could use https://localbitcoins.com/ it's a bitcoin escrow service, YMMV, read up up how it works here.
They list Harare as a place where you can trade with locals.
May be good for small amounts.
That or if you can open an bank account in Europe, USA, Australia etc (You can often do that from a large bank in your home country), wire the money to that account, then use one of the larger exchanges; like most other people do. However, that could be rather expensive with international wire & exchange fees etc. Better for larger amounts.

Buying bitcoins in Zimbabwe


Understanding the use of the [education] tag

Question: What's the use of the education tag, given that we have the learning and teaching tags?
Comment: What is the scope of [learning] tag is not clear to me *at all*, by the way. Is it supposed to be smth close to [self-study] or rather to [machine-learning]? Looks like a garbage tag to me.
Comment: Update: issue resolved (see update to Andre's answer), answer ready for acceptance :-)
Comment: @amoeba same here
Comment: Only `[teaching]` even has an excerpt. Probably we should figure out what we want the other two to mean / be used for, create excerpts, & make them synonyms or destroy them, etc.
Comment: @amoeba Thanks!
Answer: Edit:
[learning] - done.
[education] - done.

Some users consider these to be meta tags, therefore, not to so great tags.
Taking into account comments from @amoeba's and @gung's, the revised proposal is:

learning and education:

remove tags; take advantage of edits to perform full revisions (set tags properly, typos, readability, title, etc.)

teaching:

leave it as it is.
Comment: I disagree with point 1.3: I think [learning] is such a confusing tag name that we should not make it a synonym of anything but rather eliminate this tag. It seems that in most cases it refers to machine learning or to "learning" a model; this can be removed or retagged to machine-learning if needed. A minority of threads might need to be retagged into teaching or self-study.
Comment: Also, I don't quite see why e.g. [teaching] is a meta tag. Teaching of statistics is on-topic here and questions about teaching deserve their own tag. I wouldn't say it's a "bad" tag.
Comment: I think `[education]` would be best to be removed entirely, rather than made a synonym. For `[learning]`, where it means 'learning a model', we might be able to substitute `[estimation]` or `[fitting]` (I'm not sure if those should be synonyms.
Comment: Looking at it again, why don't we make education a synonym of teaching instead of retagging?
Comment: Andre, I have no idea, I did not really look. To me the tag name "education" sounds like it should be synonymous with "teaching", but perhaps in practice it's not always like that. One option is to retag all threads that do not fit [teaching] scope, and then to decide if we make a synonym or retag the rest into [teaching].
Comment: I don't like the self study tag.  I think it should apply only to homework and therefore get rid of it. What is the difference between an ordinary tag and a meta tag?  Users can create their own tags regardless of what is suggested.  So isn't the process of cleaning up tags a never ending battle? I think the education tag is meaningless.  Everything we do on this site is intended to further educate.  For CV I think the learning tag is a problem since machine learning is a major topic and the learning tag can be confused with machine learning tag.
Comment: Most of the time regardless as to which of these three outcomes occur, things end up bad for the OP.  If he wanted an answer he doesn't get one. If he only gets hints they may not be helpful enough.  Otherwise he gets no satisfactory help and his question is closed or deleted.  These questions are not homework or exam questions and I think the OP deserve an answer if the question is acceptable and someone could provide a reasonable answer. If the self study tag were eliminated none of these difficulties would occur.  Someone might see pitfalls but I don't.
Comment: Re your update: Five threads are going to be automatically deleted very soon because they are closed/downvoted (I have no downvoted some of the questions/answers to enable automatic deletion). If you downvote http://stats.stackexchange.com/questions/180284 it will also be erased (I already downvoted). So this will be 6. The other two are closed as duplicate and I think should be edited to remove the [learning] tag.
Comment: Tks @amoeba (for the comment and help getting this done). What I observed was that not all questions tagged [education] were about [teaching] (they were also about learning/self-study and career). I'd suggest wait and see if [education] pops up again. If it does, we can come back to this discussion to define a synonym.
Comment: @AndreSilva Thank you for answering my somewhat naive questions. I am going to read your post to see what the argument is for keeping self study.
Comment: I went through that post.  It was very long with long answers and too much discussion.  But the bottom line for me is that questions that are not homework are too subjectively labelled self study.  In my recent activity on the CV site I have found that the OP does not initially label the question "self study" and a moderator or other user makes the judgment (very subjectively) that the question needs the self study tag. If the OP doesn't add the tag one of three things will happen (1) someone other than the OP adds the tag (2) the OP dutifully adds the tag (3) the tag never gets added.
Comment: Well done. So do you think we should make [education]->[teaching] synonym for the future, or rather not?


Session Management Across Multiple Devices

Question: Today users wish to be logged in across multiple devices.
The fact that Joomla signs out a user from all devices when one device was signout is driving users crazy.
Can someone please help me, and explain to me how I can make sure the user session is kept and terminated only in case the user clicked the logout button on a specific device (and will keep signed in on different devices) ?
Comment: Welcome to JSE. Please take the [tour] and perhaps write something into your profile while you wait for support.  If you have made any partial progress with your research, please include your findings as an edit on your question.  Please continue researching; if you manage to resolve your own question, it is totally legit to answer your own question to the benefit of future researchers.
Answer: Disable "Force Logout for all Sessions?" option in "User - Joomla!" plugin.


How do you move the 3d cursor along an edge?

Question: I have my 3D cursor snapped to a vertice.
What is the best way to move the cursor n units along a given edge?
Answer: Bmesh helper script
For those interested in a scripting solution, here is a little helper script to place the cursor on an edge.

Test run on default cube
Test script.

Run in edit mode
Have an edge as active element.
Place the 3d cursor close to one end, this will be the zero location
Edit the pc variable to how far in percent along edge from one end to another. 0 will snap the cursor to closest end. One third will move it one third of the way to other end.
The global length of the edge is written to system console.

Test script.
<code>import bpy
import bmesh

pc = 1 / 3

context = bpy.context
scene = context.scene
ob = context.edit_object
mw = ob.matrix_world
me = ob.data
bm = bmesh.from_edit_mesh(me)
e = bm.select_history.active
assert(type(e) == bmesh.types.BMEdge)

v1, v2 = sorted((v.co for v in e.verts), key=lambda o: (scene.cursor_location - o).length)
scene.cursor_location = v1 + pc * (v2 - v1)
print("Global Edge Length: ", (v2 - v1).length)
</code>
Notes:
Could extend this to have a UI by making an operator.
Answer: A native workaround to achieve this is to subdivide the edge creating a new temporary vertice, which can be moved in local orientation, and then set the 3D cursor to that vertice.

Select the edge
Ctrl+E > Subdivide
Select the vertice, and use local transformations to move it where you want it.  This can be done by moving the 3D cursor to the start of the edge (Alt+S > Cursor To Selection), then selecting your new subdivided vertice and doing Alt+S > Selection To Cursor, Then if for example moving along the y-axis 10cm press G+Y+Y+0.1 (depending on the scene Unit settings).  Enabling Properties > Mesh Analysis > Edge Lengths helps too.
Move your cursor to selection again, and undo the changes, the cursor will remain.
Answer: Download the Enhanced 3D Cursor and install.
Select your starting vertice and open prioperties (N) and under 3D Cursor Tools choose "Set" and change the transform orientation to "Local" or "Normal".
Press F10 and on the lower left you get an X/Y/Z box to enter your local transforms.
Press LBM carefully without moving the mouse to apply the move.
This only works if your edge is the local or normal to the vertice - ie if you have a vertice with 3 edges coming off it, it will probably only work for one of those edges.  You might be able to do other edges by creating a Custom Transform Orientation (Properties (N) > Transform Orientations > New)


What is the function of the hole at the rear of the airplane?

Question: What is the function of the hole at the rear of a plane?
I searched online but didn't get a satisfying answer.
Comment: there are several hole in a typical airplane. you'll get better answers if you provide a picture.
Answer:
This one? It's the APU(auxiliary power unit)'s exhaust.
An auxiliary power unit (APU) is a device on a vehicle that provides energy for functions other than propulsion.

The primary purpose of an aircraft APU is to provide power to start
  the main engines. Turbine engines must be accelerated to a high
  rotational speed to provide sufficient air compression for
  self-sustaining operation. Smaller jet engines are usually started by
  an electric motor, while larger engines are usually started by an air
  turbine motor. Before the engines are to be turned, the APU is
  started, generally by a battery or hydraulic accumulator. Once the APU
  is running, it provides power (electric, pneumatic, or hydraulic,
  depending on the design) to start the aircraft's main engines.
https://en.wikipedia.org/wiki/Auxiliary_power_unit


How can I access an LDAP-Server to autocomplete address headers in message-mode/GNUS

Question: I'm using GNUS to access a bunch of IMAP servers. When composing new messages it would be nice to have access to the companies ldap server for autocompletion on address headers TO/CC/BCC. Is this possible, and if, how?
Comment: [Here](https://debbugs.gnu.org/cgi/bugreport.cgi?bug=16322) are some patches that try to simplify EUDC configuration.
Comment: @legoscia this looks great; time to compile master again already? ;-)
Answer: [Update per comments]
Disclaimer: I'm not using EUDC or LDAP at this time, thus I have no current setup of it.
I've had success with EUDC in the past, it wasn't complicated to setup with autocompletion.
First, I copied exactly the configuration described in the EUDC wiki page.
The only thing that I recall being an issue was making sure that I had the right LDAP base, address and binddn fields setup.
I ended up setting credentials via M-x customize-group as I far as I know.
I then replaced all the related server fields with my configuration (Copying wiki stuff here, just for inline reference...).
(require 'ldap)
(require 'eudc)

(setq eudc-default-return-attributes nil
      eudc-strict-return-matches nil)

(setq ldap-ldapsearch-args (quote ("-tt" "-LLL" "-x")))
(setq eudc-inline-query-format '((name)
                                 (firstname)
                                 (firstname name)
                                 (email)
                                 ))

(setq ldap-host-parameters-alist
      (quote (("your_server" base "ou=addressbook,dc=your_dc_here,dc=fr"
               binddn "cn=admin,dc=your_dc_here,dc=fr"
               passwd "your_password"))))

(eudc-set-server "your_server" 'ldap t)
(setq eudc-server-hotlist '(("your_server" . ldap)))
(setq eudc-inline-expansion-servers 'hotlist)

(defun enz-eudc-expand-inline()
  (interactive)
  (move-end-of-line 1)
  (insert "*")
  (unless (condition-case nil
              (eudc-expand-inline)
            (error nil))
    (backward-delete-char-untabify 1))
  )

;; Adds some hooks

(eval-after-load "message"
  '(define-key message-mode-map (kbd "TAB") 'enz-eudc-expand-inline))
(eval-after-load "sendmail"
  '(define-key mail-mode-map (kbd "TAB") 'enz-eudc-expand-inline))
(eval-after-load "post"
  '(define-key post-mode-map (kbd "TAB") 'enz-eudc-expand-inline))

Comment: Please ellaborate on how you set it up/what you have as your configuration.  Link only answers are not recommended because the link can change in the future.
Comment: The linked config does not work for me (with the relevant parts filled in with correct values); the paramters used directly with ldapsearch at the commandline gets results, emacs apparently does not even try something; is there proper documentation somewhere?
Comment: I renounce anything I said -- it works now; somewhere in my attempts to get it working I added "scope 'subtree" according to the docs for other client-systems -- that got in the way; all I had to add was "-ZZ" to the ldap-ldapsearch-args for TLS.


Is chain mail a notable claim?

Question: When checking a claim notability, does the fact the claim was perpetuating via chain mail (or several chain mails) make the claim notable? (Example question: Is "self-CPR" effective?)
Answer: A chain mail should be a fine notable claim...  That said the question here really shows no effort.  Some supporting evidence or ambiguity would make this a better question.  SE is not your typical I have a question please answer it for me site.  You are expected to try to solve the problem yourself and share what you have learned in your question.  Or at the very least find multiple sources of the claim. There is no evidence of that here.
Comment: @jozzas - I guess my point is that Skeptics should not be the first place someone turns to when they get an claim.  Finding evidence that others believe it is a sort of trying to find the answer yourself.
Comment: You shouldn't need to attempt to answer the question yourself, but a bit of effort finding some other sources of notability outside of the chain email would have been nice in this case.
Comment: Well, I have yet to see a chain mail that would survive any effort to check if it is true.
Comment: @Suma - But the point is they are widely believed.

Is chain mail a notable claim?


How can I migrate this question?

Question: I think this question that I asked ("How to reverse default [reverse-chronological] ordering of archive pages?") would be better asked on Superuser, with the words "Wordpress/Astra:" prepended to the title. Please can somebody tell me how to migrate it, or migrate it for me if only a moderator can do that. Many thanks!
Comment: I would note that what you're asking for in the Q is how WP already works out of the box. You should contact Astra dev support for help with bugs in the Astra theme
Answer: I don't believe the question is related in any way to the SuperUser stack. Super User isn't a stack for developer/programming questions. It's for power users.
If people voted to close the question with the migration clause, or a moderator did it, I believe it would either be migrated back here, or closed outright. That doesn't mean it's on topic here, just that they're trying to be helpful.
For an authorative answer on wether the Q is on topic at SuperUser, you'd need to either ask on their meta site, or succesfully migrate the Q there without it being closed.
Remember, people on Stack Exchange aren't employees, they're volunteers and users. Nobody here gets paid, and we don't know all the ins and outs of other stacks.
As for the Q:
The problem seems to be that the question is difficult to understand, and looks like you're asking for support for a bug in the Astra themes archive ordering. I've made adjustments to try and make it easier to understand, and make it harder to misinterpret
Comment: So asking how to achieve something is off-topic but knowing what tool to use and asking how to use that tool to achieve it is on-topic? On-topic where? I'll ask it where it's on-topic.
Comment: No, that's a mischaracterisation of what I said. You have a question about a 3rd party theme, that's offtopic. It doesn't matter what you're asking about that theme, or if it's a great or an awful question, that subject is not in this stacks scope, it's offtopic, this isn't the place to ask. Super User is not the the place to ask either. **The best place to ask is the theme vendor**,  afterall it's a premium theme, people trying to answer your question need to pay money to even begin to debug your problem
Comment: It's not about the theme. I mentioned the theme for background. Wordpress is written in PHP. It's about WP and therefore PHP. A bit of PHP in a child theme will override any theme. Astra is not a premium theme - a paid-for "Pro" version exists, but I am using the free version. So there is no "theme vendor" relevant to my question who can be asked anything. I posted the question to Superuser, but they migrated it back here, "because it can be answered on WordPress Development Stack Exchange" (their words). Clearly the right hand of the company doesn't know what the left hand is doing.
Comment: The people who wrote Astra are the theme vendor, wether it's paid for or not doesn't change that. Aside from the 3 official support routes, if they're on .org they must provide support, it's the price they pay .org for hosting: https://wordpress.org/support/theme/astra/
Comment: As for the right hand of the company, i'm not an employee, neither are the people at superuser **we're all volunteers**. SuperUser users won't be intimiately familiar with WPSE's scope, just that it has WP in the name, they were just trying to be helpful, I did say they'd migrate it back. And if it were a generic PHP question, then stackoverflow would be the stack for it. WPSE is not the place to ask though, the vendor of the theme Astra, its makers, are where you need to go, and they've provided a FB group, paid support, docs, and a .org support forum
Comment: @ruffle I've gone back to the original question, and believe the problem is that it was very, **very** difficult to understand, and found an alternative interpretation. Your question reads as: "In my archive posts are ordered by their post ID and i want them ordered chronologically", but now I suspect you actually meant "How do I reverse the numbering of the pagination". Is this the case? Because that question would be on topic
Comment: I've closed the migrated Q as a duplicate, reopened the original, and tried to edit it to make it more obvious that you're actually asking about the pagination numbers, not a bug in Astra. I think the root of the problem is that the Q was just really difficult to understand, and that the Q title made no mention of what you wanted

How can I migrate this question?


Editing pages from dashboard

Question: I keep struggling to understand how and why this happens: in some themes I can modify the content of a page (type page) from the dashboard, in others I can't. For instance, if I activate a default theme, say Twenty Fifteen, I can create and edit pages from dashboard. When I creat a theme from scratch, I can add a new page from dashboard, but the content added there is not showing up in the website so editing isn't possible either (my theme has only few files created: 404, footer, header, functions, index.php and style.css). When I visualize a page in the website (local), it displays the index.php content instead of the content from the dashboard. So what is the difference between the wp default themes and the one I created from zero? Please help me understand this. I didn't find any satisfying explanations on Google and posting here is kind of my last resort. Thanks in advance for any help!
Answer: to display page content in custom theme you should use page.php template,
and call the_content() inside the loop.
You can also create custom template for different pages and assign them in back end.
See: https://developer.wordpress.org/themes/template-files-section/page-template-files/
Comment: So this is the main practice? Now, that I saw your explanation, I checked again the code behind Twenty fifteen theme and saw they used the_content() as well.
Answer: I think You should use the word press default loop  for getting posts.
<?php
if ( have_posts() ) :
    while ( have_posts() ) : the_post();
        // Your loop code
         the_content();
    endwhile;
else :
    echo wpautop( 'Sorry, no posts were found' );
endif;
?>

Editing pages from dashboard


Implementing `__dir__` in Python: Does it need to return a list and does the list need to be sorted?

Question: I have a class that implements the __dir__ method. However, I am not entirely certain about some nitty gritty details of the dir API.
A: Is it really required that __dir__ returns a list? My implementation is using a set to avoid listing attributes twice, do I need to convert it to a list before returning? From the documentation I would guess it has to be a list:

If the object has a method named dir(), this method will be called
  and must return the list of attributes.

However, would not returning a list break functionality at some point?

B: Does the result need to be sorted? The documentation is a bit ambiguous here:

The resulting list is sorted alphabetically.

Does this mean, calling the built-in dir automatically sorts data returned by __dir__ or does it mean dir expects sorted data from __dir__?
EDIT: Btw, my question encompasses Python 2 (2.6 and 2.7) and 3 (3.3, 3.4).
Answer: Under Python 2.7.3, the answers are:
A: Yes, it must be a list:
>>> class F:
...     def __dir__(self):
...             return set(['1'])
...
>>> dir(F())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: __dir__() must return a list, not set

B: No, dir will sort it.
>>> class G:
...     def __dir__(self):
...             return ['c','b','a']
...
>>> dir(G())
['a', 'b', 'c']

Answer: Under Python 3, you can return any sequence, including a set, and you need not sort it.
The corresponding documentation doesn't exist under Python 2, so I'm not sure what you're expected to do there.
Answer: In Python 2, it must be a list. Otherwise you get a TypeError when you run the dir() function on a corresponding instance.
class Dirry(object):
    def __dir__(self):
        return set('andy pandy mandy sandy'.split())

d = Dirry()
dir(d)

Yields:
      5 d = Dirry()
----> 6 dir(d)

TypeError: __dir__() must return a list, not set

If returned as a list, it does not need to be sorted. The dir() function will sort for you:
class DirryList(object):
    def __dir__(self):
        return 'andy pandy mandy sandy'.split()

d = DirryList()
dir(d)

Yields:
['andy', 'mandy', 'pandy', 'sandy']

Even though it was not given by __dir__ in sorted order.


Objects moving when I drag them

Question: Im no pro with Illustrator, but I can work my way through it pretty well. I was working on some type today, and every time I click on an object to place it somewhere,when I get to my destination, the object is shaky. I have to move it back and forth a few times to get it  in place. I'll place it where it should be, and it moves just a tiny bit. Not accurately I guess I'm trying to say. It just started happening in the last few weeks and is driving me nuts. Any ideas?
Comment: Possibly aligning to pixel grid?
Comment: Could be a slow computer lagging so that the object is released with a slight delay.
Answer: Could be grid snap, or pixel grid alignment. You can try turn off both options.
For grid snap go to View menu and uncheck Snap to Grid.
For pixel grid open the Transform panel, select the object and uncheck Align to pixel grid.

Objects moving when I drag them


Question location

Question: Yesterday I posted this question on Mathematics Stack Exchange. Except for the one upvote it didn't receive any attention. What is the problem with my question? Is it too vague? Should I better include an example? I am hesitating whether I should have posted the question on MathOverflow instead of this SE. Should I change the location of the question?
Comment: (1) In a site with that much traffic, getting one upvote is something to begin with. (2) Why do you think this question should be on MathOverflow?
Comment: Because it is not a typical mathematics question that can be answered with a proof or a calculation.
Comment: And you think that all questions on this websites are just questions that can be answered by calculations or proofs? Or that the questions on MathOverflow are different somehow?
Comment: By the tone of your question, I guess the answer is no...
Comment: Last but not least, this is not a good reason to delete that question.
Comment: But I posted the question on another stackexchange?
Answer: The mere fact that a question does not get much attention does not in itself mean the question is lacking. The subject you ask about is not one that gets that much attention in general on this site.
However, I feel your question is also quite broad and possibly a bit hard to parse. The introduction of $t$ is not quite transparent, but as it is not my field and I still can sort of get the point it should be fine. But it is still quite broad a question.
To ask this question on MO does not strike me as a good idea, for one thing as this type of mathematics is not that well-represented on MO either.
If I had this type of question I would ask it on the site for Computational Science. The point that the question is a bit broad rests though.
If you want some specific advice: try to focus the question a bit more, and ask it on that site.
Comment: That Computational Science website looks indeed interesting. I will post it there. About my question, I had hoped that there would be a general answer, but it's clear that I should be more specific.
Comment: I am glad you found the information helpful. I think there is a very general answer, in that if you have one variable and then/thus consider say a subset of $[0,1]$ and you descretise to have to have a distance of $.01$ than you have about $100$ points (technically $101$). If you . have two, you'd look at $[0,1]^2$ and then you'd need $100^2=10^4$. points for about the same resolution. With $5$ vqariables youd be at $10^10$ and so on. The growth in the dimension is exponential. See https://en.wikipedia.org/wiki/Curse_of_dimensionality But with a more focused q you'll get better answers.
Answer: I think the question is rather vague and would be improved by including an example. Right now, the answer would appear to be "Well, it depends on what $f$, $t$ and $g$ are" - which isn't a very compelling answer. I'd bet it also depends on the method you're using for numerical optimization. In any case, being more specific would make the question substantially more answerable.
Also, it's worth noting that not receiving much attention isn't necessarily because there's anything wrong with the question. Sometimes that's just how it is.
(And, I'm not a regular on MO, but it doesn't look like a question about research level mathematics; it seems somewhat elementary, just vague)

Question location


Dynamic Splitter Panes

Question: How would I go about implementing dynamic/docking splitter panes in a vb.net app similar to visual studio?
Answer: Check out the following demo at ZettaCube, their WebDock component seems to have functionalities close to VS.NET, especially docking and auto-hide.
http://www.zettacube.com/
Comment: zetta is now out of business.
Answer: DockPanel is one painless & open source way to do it.
Answer: DockPanel is for WinForms only.  Seems that the WebDock from zettacube above is the only solution for now.
Answer: Not easily is the short answer.
A high level idea would be to define some regions using divs or a table and using your js framework of choice make these elements resizeable.   that gets you the splitter aspect.
The docking will have to use absoluting positioned elements that you can drag and drop and if you are currently over a docking element, reposition the element to be docked to inside the docking element and change it's position back to normal.  When you want to drag it out you will change it's positioning back to absolute
Also, this is not easy to do and will take a long time and still probably not work correctly.  Sorry to sound pessimistic though.
Answer: I would say use some of the already available controls out there.
I use the control library from Janus Controls, but there are dozens out there to choose from.
http://www.janusys.com/controls/
Agree with Nick, this is not something you just throw together yourself.

Dynamic Splitter Panes


Is there a maintenance mode in Wordpress core?

Question: If I want to put a Wordpress (3.2.1) site into Maintenance mode, is it still necessary to use a plugin? If so, is this a good option?
Answer: Yes there is. But it is primarily meant for short interruptions (such as during upgrades) and not very user-friendly. WP creates <code>.maintenance</code> file in root (with timestamp info about time) to trigger it and removes after it is done.
See WordPress Maintenance Mode Without a Plugin for reference.
In practice using a plugin is usually more convenient and functional.
Answer: There is no maintenance mode in core AFAIK.
And as far as plugin's go, I prefer JF3 Maintenance Redirect as it allows IP address whitelisting.


Which Scripture tells the Complete Story of Lord Hanuman?

Question:
We can know about Lord Hanuman from Ramayana but it states only a small portion of his life.
Is there a scripture that tells about Lord Hanuman's story completely ?
Answer: Valmiki Ramayana has the life of Hanuman which happened in Treta Yuga only. But the life of Hanuman is indeed wide in scope. He has been immortal since ages. He is alive even today.
Why didn't Sage Valmiki focus on Hanuman like he did on Sita and Rama?
Ramayana doesn't mean the story of Rama but it is the life/history of Sita.
Balakanda, chapter 4 clearly states that.

काव्यम् रामायणम् कृत्स्नम् सीतायाः चरितम् महत् |
  पौलस्त्य वधम् इति एवम् चकार चरित व्रतः || १-४-७
Meaning:
  That sage with observed sacred vows has rendered the entire epic in the name of 'Ramayana', 'Sublime Legend of Seetha' and 'elimination of Ravana'. [1-4-7]

So, Ramayana only discusses about Sita and Rama who is incomplete without
Sita.
Then which scripture discusses the complete life of Hanuman?
The answer is Parāśara saṃhita. The seer of this scripture is Parāśara( Father of Krishna Dwaipayana vyasa). In this scripture, life of Hanuman before Ramayana and the life of Hanuman which happened in Dwapara yuga are also present.
But some aspects in this scripture are not accepted by some people. For example  this book says Hanuman is married to Suvarchala, daughter of Sun God. On the contrary, our puranas, Mahabharata say Suvarchala is wife of Sun-God. See this question for details.
Parāśara saṃhita is also translated into Telugu and English languages.
You can learn more about Parāśara saṃhita from this page. Here is Parāśara saṃhita in sanskrit.
Comment: lord hanuman's mother was seen by lord ram after war that means hanuman's age was equal or slightly higher(if lord ram is 25 then lord hanuman would be 30 or other) than lord rams age.As ramyana is present and why same period lord hanuman scripture is NOT AVAILABLE
Comment: @Sakthi Ramayana is Sita and Rama story. There is no need to add the role of Hanuman. Parasara maharshi wrote parasara samhita which include birth, marriage(this is not accepted by some),  life in Dwapara yuga. Click the link I have added in the answer. You will find the parasara samhita chapters. It is not available online. Hard copies are available in some book stores. You may ask the website for more details.


Tableau UI automation

Question: Selenium does not recognize webelements of Tableau. Is there any tool which is successful for UI automation of Tableau ?
Answer: You have two commercial options:

https://kinesis-ci.com

Kinesis is a test framework that adds automated testing and continuous integration capability to your Tableau Server.

https://www.datagaps.com/bi-testing-tools/bi-validator/automate-tableau-testing/

BI Validator makes use of our patented ELV Architecture to automate BI Testing. It supports extraction of reports and report metadata from Business Intelligence tools such as OBIEE, Tableau, Cognos and Business Objects. The reports are loaded into a repository (Oracle and PostgreSQL) so that validations can be run on it.

Tableau UI automation


Is reheating partially fried fish safe?

Question: A street side stall selling fish fries them two times for convenience.Initially they fry the fish for 70%, then keep it for 10 to 20 minutes. When a customer comes they fully fry that fish.
Is this safe?
Comment: It depends how the fish is stored between fry; it should be stored in a cold environment (cold box, fridge...)
Comment: @Max it is stored a open container where atmospheric temperature  (25-35 degC). what happens if its stored in this condition for 10-20mins like I said in question.
Answer: It's absolutely safe, and many professional cooks do this sort of thing all the time. Check out the ordinances for your local health department— some require a variance for using time rather than temperature as a food safety measure– but most are fine with par cooked meats being in the danger zone, usually defined as 40 to 140, for up to 2 hours if they get thrown out right away. If you par fry and cool the fish, then you should be bacteriologically safe for much longer, but it would probably be of pretty poor quality when you fried it. Nobody wants to eat an oil sponge. Keeping your oil temp up will help you keep it less greasy.

The Danger Zone... This refers to the range of temperatures at which bacteria can grow - usually between 40° and 140° F (4° and 60° C). For food safety, keep food below or above the "danger zone." Remember the 2-Hour Rule: Discard any perishables (foods that can spoil or become contaminated by bacteria if unrefrigerated) left out at room temperature for longer than two hours. When temperatures are above 90° F (32° C), discard food after one hour.

Though it varies from jurisdiction to jurisdiction, that 2 hour period usually starts over when the food is brought back up to finishing temperature... so if you par cooked it, held it for almost two hours and nobody got it, you could bring it up to temperature and then have another two complete hours to do something with it, or cool it and store it. Not sure what good prefried fish would be though.
You could avoid this whole thing if you had the extra time on hand for someone to butterfly the cuts so you could just fry them quickly to order.

Is reheating partially fried fish safe?


I sent my Humaniq & Taas coin (from my ico purchase) to my Parity Wallet.

Question: Being a newb to crypto I screwed up. I sent the taas and humaniq coins I bought during their ico to my Parity wallet. Nothing has appeared and I now think that maybe this wallet only supports ethereum? Are my coins lost forever or can I recover somehow?
Comment: Are you fully synchronized? Parity supports tokens very well.
Comment: By parity wallet do you then mean an account that you have in your parity wallet? If so, this account should now hold the tokens you're talking about. Can you provide your account address? Then we can check.
Answer: although I am not totally familiar with TaaS, humaniq and parity, all you need to do is to be able to sign transactions with the account that now owns the tokens.

There must be a way of exporting key files with parity, I assume they are stored in a data dir somewhere.
Import the key file to MetaMask, a plugin for Chrome to connect to the Ethereum network and do/sign transactions through the browser.
If there is a web interface for transfering these tokens, just open it, and - with metamask initalized by klicking the fox icon - you can now transfer your tokens wherever you want to, because to TaaS and humaniq, you are identified as the owner of the tokens now.

Good luck !
Answer: Have you set a watch on the token contract within Parity? Due to the way tokens work on the Ethereum network, they don't show up in your wallet by default, you have to add them as a currency to watch.
To watch a token balance:

If you don't have a contracts tab, go to settings and enable it
Go to the contracts tab and click "watch contract"
Enter the contract address of the token you want to watch (Humaniq, then repeat steps 2-3 with Taas).


Carolina reaper leaves turning brownish and veiny

Question: I planted 2 seeds about 3 weeks ago and the plant seemed to grow pretty much okay then the leaves started to turn kinda Brown and now it stopped completely it's growth. They almost have full sun all day, maybe it's too much?
Comment: How hot is it getting near the pots? Have fertilized? If so, how much of what? Peppers will stop growing if they get too much nitrogen, however that does not usually make for brown veins. How often watered? Drainage? What's the soil? Peppers don't much like peat moss.
Answer: It's hard to see, but that looks like mould. I also notice that the out-of-focus potting medium looks very dark, which is not in itself an issue, but most composts tend to appear darker when wet.
So my first thought is - how much are you watering these plants? Chilli peppers are from hot, and often fairly dry climates, and are not fond of an abundance of water. These are young to go very long without water, but being on the cusp of wilting before being given more would be absolutely fine for these. They also look to be in a planter. Do the pots have drainage holes in the bottom? If not, you must be very careful not to have any water pooling in the bottom of the pot - as you can't see this, the only way to judge this is by common sense and erring on the side of too dry.
Comment: I think to problem is I overwatered them too much. Also the soil I bought for the pepper is specifically made for the Carolina reaper (at least that's what was written on the bag).


Can a Last Will legally specify beneficiaries at a specified url?

Question: Can a Last Will legally specify beneficiaries in an external document? For example, can the Last Will point to a url that shows a list of beneficiaries?
Comment: I would say that it can... but anybody who is not happy with the result will have way more opportunities of challenging the last will in court (for example, by claiming that the heirs were able to manipulate the contents of the page).
Comment: Yes, but why the URL if you don't mind me asking?
Comment: A Will is specifically a long-term document that cannot be altered or forged; a URL doesn't seem to have those qualiities. But if you can get round that problem,  I see no reason why not.
Comment: Hello Annie!  Welcome to Law.SE.  Please read our tour page, which is linked at the bottom of the page.
Answer: This is a close call, in the example that you suggest, because it won't have been executed with the proper formalities and it isn't clear that the content at a url would be fixed in its language at the time that the Will is executed. Subject to an exception for personal property memorandums (and a more subtle one for powers of appointment in trusts) you can't change the terms of a Will once it is signed except by a Codicil executed with the same formalities.
Certainly, the best practice would be to assume that the answer is no.
There are times when a reference to an external document in a will is allowed (e.g. a reference to real property by address rather than a full legal description found in a recorded deed), but a list of beneficiaries would ordinarily not be allowed unless it was effectively a reference to vital statistics records (e.g. "all children born to or adopted by me.")
In general, references to external documents are not allowed when used to establish the nature of the testator's donative intent (a "testator" is someone who writes a will), unless it "describes the writing sufficiently to permit its identification" and can't be modified after the Will is signed, but can be used to establish general facts about reality.
One exception in Colorado is that a "personal property memorandum" designating who will receive specific items of tangible personal property can be incorporated by reference and does not have to be executed with the same formalities as a will. It isn't clear to me if a url could be a valid personal property memorandum and that issue has never been tested in Colorado.
Colorado's probate laws are based on the Uniform Probate Code and would be substantially identical to any other jurisdiction that adopted the Uniform Probate Code's substantive provisions.
The primary statutes governing this (which aren't necessarily easy to understand without context) are:

Colorado Revised Statutes § 15-11-502. Execution--witnessed or
  notarized wills--holographic wills
(1) Except as otherwise provided in subsection (2) of this section and
  in sections 15-11-503, 15-11-506, and 15-11-513, a will shall be:
(a) In writing;
(b) Signed by the testator, or in the testator's name by some other
  individual in the testator's conscious presence and by the testator's
  direction; and
(c) Either:
(I) Signed by at least two individuals, either prior to or after the
  testator's death, each of whom signed within a reasonable time after
  he or she witnessed either the testator's signing of the will as
  described in paragraph (b) of this subsection (1) or the testator's
  acknowledgment of that signature or acknowledgment of the will; or
(II) Acknowledged by the testator before a notary public or other
  individual authorized by law to take acknowledgments.
(2) A will that does not comply with subsection (1) of this section is
  valid as a holographic will, whether or not witnessed, if the
  signature and material portions of the document are in the testator's
  handwriting.
(3) Intent that the document constitute the testator's will can be
  established by extrinsic evidence, including, for holographic wills,
  portions of the document that are not in the testator's handwriting.
(4) For purposes of this section, "conscious presence" requires
  physical proximity to the testator but not necessarily within
  testator's line of sight.
(5) For purposes of this part 5, "will" does not include a designated
  beneficiary agreement that is executed pursuant to article 22 of this
  title.

and

Colorado Revised Statutes § 15-11-503. Writings intended as wills
(1) Although a document, or writing added upon a document, was not
  executed in compliance with section 15-11-502, the document or writing
  is treated as if it had been executed in compliance with that section
  if the proponent of the document or writing establishes by clear and
  convincing evidence that the decedent intended the document or writing
  to constitute:
(a) The decedent's will;
(b) A partial or complete revocation of the will;
(c) An addition to or an alteration of the will; or
(d) A partial or complete revival of the decedent's formerly revoked
  will or a formerly revoked portion of the will.
(2) Subsection (1) of this section shall apply only if the document is
  signed or acknowledged by the decedent as his or her will or if it is
  established by clear and convincing evidence that the decedent
  erroneously signed a document intended to be the will of the
  decedent's spouse.
(3) Whether a document or writing is treated under this section as if
  it had been executed in compliance with section 15-11-502 is a
  question of law to be decided by the court, in formal proceedings, and
  is not a question of fact for a jury to decide.
(4) Subsection (1) of this section shall not apply to a designated
  beneficiary agreement under article 22 of this title.

and

Colorado Revised Statutes § 15-11-510. Incorporation by reference
A writing in existence when a will is executed may be incorporated by
  reference if the language of the will manifests this intent and
  describes the writing sufficiently to permit its identification.

and

Colorado Revised Statutes § 15-11-511. Testamentary additions to
  trusts
(1) A will may validly devise property to the trustee of a trust
  established or to be established (i) during the testator's lifetime by
  the testator, by the testator and some other person, or by some other
  person, including a funded or unfunded life insurance trust, although
  the settlor has reserved any or all rights of ownership of the
  insurance contracts, or (ii) at the testator's death by the testator's
  devise to the trustee, if the trust is identified in the testator's
  will and its terms are set forth in a written instrument, other than a
  will, executed before, concurrently with, or after the execution of
  the testator's will or in another individual's will if that other
  individual has predeceased the testator, regardless of the existence,
  size, or character of the corpus of the trust. The devise is not
  invalid because the trust is amendable or revocable, or because the
  trust was amended after the execution of the will or the testator's
  death.
(2) Unless the testator's will provides otherwise, property devised to
  a trust described in subsection (1) of this section is not held under
  a testamentary trust of the testator, but it becomes a part of the
  trust to which it is devised, and is administered and disposed of in
  accordance with the provisions of the governing instrument setting
  forth the terms of the trust, including any amendments thereto made
  before or after the testator's death.
(3) A revocation or termination of the trust before the death of the
  testator causes the devise to lapse, but exhaustion of trust corpus
  between the time of execution of the testator's will and the
  testator's death shall not constitute a lapse; a revocation or
  termination of the trust before the death of the testator shall not
  cause the devise to lapse, if the testator provides that, in such
  event, the devise shall constitute a devise to the trustee of the
  trust identified in the testator's will, and on the terms thereof, as
  they existed at the time of the execution of testator's will, or as
  they existed at the time of the revocation or termination of the
  trust, as the testator's will provides.

and

Colorado Revised Statutes § 15-11-512. Events of independent
  significance
A will may dispose of property by reference to acts and events that
  have significance apart from their effect upon the dispositions made
  by the will, whether they occur before or after the execution of the
  will or before or after the testator's death. The execution or
  revocation of another individual's will is such an event.

and

Colorado Revised Statutes § 15-11-513. Separate writing or memorandum
  identifying devise of certain types of tangible personal property
Whether or not the provisions relating to holographic wills apply, a
  will may refer to a written statement or list to dispose of items of
  tangible personal property not otherwise specifically disposed of by
  the will, other than money. To be admissible under this section as
  evidence of the intended disposition, the writing shall be either in
  the handwriting of the testator or be signed by the testator and shall
  describe the items and the devisees with reasonable certainty. The
  writing may be referred to as one to be in existence at the time of
  the testator's death; it may be prepared before or after the execution
  of the will; it may be altered by the testator after its preparation;
  and it may be a writing that has no significance apart from its effect
  on the dispositions made by the will.

There is not a statutory definition of a "document" or a "writing" in the Colorado Probate Code.
Answer: Yes
But why?
A will is static. Once made it can only be changed by codicil, however, it is generally recommended that you don't do this - write a new will revoking all former wills instead.
The last thing your heirs want to worry about when they are (presumably) grieving your death is a hard to interpret will written in a non-conventional way. At the end of that road are lawsuits and estranged families.
Comment: A codicil is only for small changes or additions, where you want to preserve the rest of the will. Also, you would have to have the info on the URL notarized in some cases in the U.S.
Answer: In the U.S. a codicil is for small amendments, but you can draft a new will if you choose to make large changes or to change the entire document.
https://www.wikihow.com/Update-Your-Will
You can use the URL, but a will is intended to be notarized so you should have a copy of whatever is on the website notarized. That would kind of defeat the purpose of the URL, but it can be done.
Comment: There is no *requirement* that a codicil be only for small amendments.  It could rewrite the whole document if the testator so chose.  (Of course, that would be a terrible idea; but that doesn't mean it can't be done.)
Comment: @MartinBonnersupportsMonica It's just semantics I guess, but the word codicil literally means amendments.
Comment: It was the *small* I was querying, not the *amendments*.
Comment: I understand, but again, by definition, an amendment would not be the whole thing, so it would in fact be smaller than the whole thing.
Comment: "by definition, an amendment would not be the whole thing".  I don't see anything in https://www.merriam-webster.com/dictionary/amendment which suggests an amendment can't replace the whole thing.  Also a change to half the document would be "smaller than the whole thing", but not "a small change".
Comment: That does not even make sense. I like you and I don't mean that in a rude way, but of course an amendment is not the whole thing.


How can I buy options for foreign stock indices?

Question: I'm a frequent trader of SPYW, and I'm interested in learning how I can get my hands on something similar for foreign exchanges like SHCOMP and JPX. Can that be done with American brokers?
Answer: Have a look at FXI ETF options (China) and EWJ ETF options (Japan). These have very liquid options and are the most convenient US based way to trade volatility of foreign stock indices/markets.
You will find similar products for other countries too, such as EWZ for Brazil.
FXI and EWZ even have a volatility index like the VIX (same methodology) calculated and published by CBOE (VXFXI, VXEWZ), which is always a sign of good options liquidity.
Answer:
How can I buy options for foreign stock indices?

Indicies can be traded in three ways:

Futures Trading
By buying and selling futures, or options on futures on the index.  These are typically traded on a futures exchange.
Trading ETFs
By buying and selling Exchange Traded Funds (ETFs), or options on exchange traded funds.  The ETFs are typically traded on a stock exchange (sometimes called a "cash market"). The options are usually traded on a separate exchange from the exchange that trades the ETFs - an options exchange.
There are also mutual funds, investment trusts and 'tracker' funds, but these do not have options unless they are exchange traded.
"Basket Trading" Stocks
By buying and selling the individual (component) stocks as a group, or options on those stocks that make up the index.  Again, the options are usually traded on a separate exchange from the exchange that trades the stock, and also traded on the same stock and options exchanges as the ETFs.

Typically futures and stocks are regulated differently (for example in the US, the SEC (Securities & Exchange Commission) regulate trading of stocks and options on stocks, while the CFTC (Commodities & Futures Trading Commission) regulate trading on futures, including equity index futures).
Futures tend to be less heavily regulated and therefore more accessible overseas though they tend to be oriented more towards the institutional investor, so the contract sizes tend to be large and the settlement and pricing methodologies quote complicated.  For example, futures don't require up-front payment, but instead require daily payments of the difference between the price paid and the market price of the underlying security.
Stocks and options on stocks tend to be more tightly regulated.  For example the SEC prohibits US persons from buying options on stock from a non-SEC regulated options exchange (i.e. a foreign one).

Can that be done with American brokers?

If you are (1) a US person, and (2) you're buying stock or ETF options, then no you can only buy those that are listed on a US options exchange.
The US futures markets tends to have listings for foreign indices but you should also be able to use a US broker to trade options on futures on European futures markets.
Some Examples

The Japanese Stock Market Index is the Nikkei 225.
Futures on the Nikkei 225 can be traded on CME (US) EUREX (Germany), SGX  (Singapore) and many other countries; There are also dozens of ETFs that try to replicate the nikkei 225 or similar benchmarks.
The CME trades the FTSE China 50 Index.

When choosing an index, you should look at how heavily traded the index is compared with the others (higher volume is usually better, taking price into account); the fees associated with the product, and the availability and spread for options on that index.

How I can get my hands on something similar...?

Identify the security that you wish to trade by reviewing the prospectus of potential candidates.
Find out what exchange(s) the product is traded on (usually detailed in the prospectus).
Look at the exchange's membership lists to see if your broker is there, or one that you wish to open an account with.
Consult your broker to see if they have the features that you want and the costs of transactions, etc. are appropriate, and if the products are suitable for you.  They may ask you disclose personal financial information to help them make that determination.

Risks
Also - options are a risky product.  So risky that a US securities broker is not allowed to discuss a specific options strategy with you until you have read and understood the OCC Risks & Disclosures Document.
https://www.theocc.com/components/docs/riskstoc.pdf (down for maintenance at the time of writing)
http://www.goldmansachs.com/disclaimer/salesandtrading/theooc-doc.pdf (secondary link)
These also relate to equity and ETF options.  Additional and different risks apply to futures and futures options.  In many cases you can lose more money than you started with(!)


Electrical Question for Receptacles in guest house

Question: Wiring a out door shed that has everything that a home does; bathroom kitchen living room and extra bedroom. Pretty much like a guest home you can say. When I run my wire in the bathroom of it. The GFCI Receptacle does it have to be on a separate circuit than the lights in the bathroom ? Does every receptacle in the bathroom have to be GFCI? I am wanting it to be by the book according to code.
Comment: You're getting the required permits and inspections for this work right?  Doing everything to code is nice, but you can still get in trouble if you're working without permits.
Answer: There is no requirement for GFCI receptacles anywhere.
GFCI protection is what is required.  That can be in many locations - a breaker, switch, deadfront or indeed a receptacle.  Further, each can protect downline locations so they too are GFCI protected.
Having more than one GFCI per breaker trip circuit indicates someone doesn't understand this concept and perhaps should not be designing wiring schemes.  Unless you have a very unusual situation, but that should only ever come up in retrofits, not new construction.
There are restrictions on bathroom circuits which are beyond the scope of this question. Bathroom lights can be on a receptacle circuit that serves only that bathroom.  The lights do not need to be GFCI protected unless they are in the shower area.
For the convenience of bathroom users, it can be helpful to have 2 or even 3 receptacle circuits (breakers) in a bathroom so someone can plug in both a hair dryer and a curler without tripping the breaker.  Each circuit needs a GFCI protective device.  That could be multiple GFCI receptacles; that is fine.
Answer: You can put everything for the bathroom on 1 20A circuit, as per the Exception to NEC 210.11(c)(3).  All receptacles in a bathroom require GFCI protection but the lights and fan do not require GFCI protection.
Comment: I think the light/ fan needs a dedicated 20 Amp circuit if it has a built in heater... I got nailed on that once in my younger years.
Comment: If it has a heater it would because it would be fixed heating. But the op did not mention heat, but I agree +
Answer: It is rather unusual to have more than one receptacle outlet in a bathroom. A receptacle outlet can consist of 4 individual receptacles mounted in the same box. That means that two of the common duplex receptacles; which is two receptacles which will each except a cords plug mounted in the same yoke; mounted side by side in a two gang box is still only one receptacle outlet. The place to install the required receptacle outlet is beside the basin since that is the only place in the bathroom that the code requires a receptacle outlet. The code allows you to have other loads besides the required receptacle outlet on the same circuit as long as that circuit serves only loads which are located in the same bathroom. I took advantage of that when I was still a working electrician to get power for the vanity mirror lights without having to drop a feed down from the overhead lights.
Best practice is to do as someone else already suggested and run 2 20 ampere circuits to the Box in which the basin receptacles will be mounted. That way each of the duplex receptacles mounted in that box is supplied by it's own 20 ampere circuit and overloading either of them becomes unlikely. If the code has not yet required Arc Fault Circuit Interrupter (AFCI) protection for bathrooms you could run those two circuits as a multiwire branch circuit in a single 3 wire + Ground cable. You would either use a handle tie on the handles of two adjacent single pole breakers or a double pole breaker. The underlying principal is that in order to turn off one of those circuits you will have to turn them both off. If AFCI protection is required for bathrooms in your community then you will need to use 4 wire + Ground cable with one circuit on each pair of wires in the cable. That would be to avoid the rather high cost of a double pole AFCI breaker
If the basin is on the same wall as the tub/shower opening or on an adjacent wall and near the opening into the shower or tub area best practice is to put the receptacles on the side of the basin away from the tub or shower. Good practice would also include providing a shelf near the receptacle to hold items which would remain plugged in such as toothbrush or shaver chargers... That shelf could be the top of a vanity cabinet but in the absence of a vanity provide a real shelf which is not the edge of a basin.


How to document Oracle database?

Question: I'm new to Oracle databases. I have used to SQL Server and the description fields (MS_Description) for tables and columns for documentation purposes. Is there an equivalent for Oracle? What is the best practice for documenting Oracle database?
Comment: you might also be interested in [this related question](http://dba.stackexchange.com/q/515/1396)
Answer: In Oracle, you would use the COMMENT command to:

[...] add to the data dictionary a comment about a table or table
  column, view, materialized view, operator, indextype, mining model, or
  edition.

Most tools (PL/SQL Developer, Toad...) will display these comments in appropriate fields when you browse the database schema.
The comments can be queried directly with the *COMMENTS dictionary views, such as ALL_TAB_COMMENTS.
Answer: In Oracle there are table and column comments that can be used for documentation.
These comments can easily be added by the following commands:
COMMENT ON TABLE my_table IS 'Documentation of my table'
/

COMMENT ON COLUMN my_table.my_columns IS 'Documentation of my column'
/

Answer: Oracle exposes its data dictionary through views. You can use these views to query the information you need.
The main views that you'll need to use are:

DBA_OBJECTS - lists all DB objects
DBA_TABLES - list all tables (and their owners, which are schemas in Oracle)
DBA_TAB_COLUMNS - list all tables and their columns

There are also ALL_% and USER_% equivalents of these views (eg: `USER_TABLES) that only show all objects you have permission on, and objects you own.
Comment: Thanks for this answer but I think you misunderstood my question. I know that I can query these objects, but how can I write my own metadata e.g for columns? If if have a column `CustomerID` I might want to add 'Surrogate id generated by ETL-process`. See for example this [link](http://sqlblog.com/blogs/michael_coles/archive/2010/01/12/t-sql-tuesday-easy-extended-properties.aspx)
Answer: If you need to do it within Oracle database then comment command is your answer. But there are couple of disadvantages of documenting schema that way:

certain privileges are required (not always possible)
in some cases you can't interfere with (3rd party/legacy) database
you can't use long descriptions (limit to 4000 characters)
you can't use or formatted text (directly)
you can't add images
no easy way to browse documentation

I'd recommend storing documentation in dedicated repository - check Dataedo database documentation tool. It reads schema (and existing comments) and lets you describe every item with rich text and images (for your ERD diagrams). You can then export to nice PDF document or interactive HTML. When schema changes you can sync your documentation with couple clicks.
I'm the product manager of Dataedo.

How to document Oracle database?


What do I put in the generator-settings area in server.properties?

Question: So I'm trying to make a custom superflat world on my server. The wiki says that I need to put flat as the level-type, and I need to modify the generatorName, generatorVersion, and generatorOptions. The thing is, there's no more info on this, although I think it might be important. But for now, I found this thing called generator-settings line in my server.properties that was originally blank. The wiki says that it is "The settings used to customize world generation. See Superflat and Customized for possible settings and examples." But there is no more info about it in the superflat page. So what do I put there? I've tried doing the preset but that doesn't seem to work. Am I doing something wrong here?
Comment: I have a discussion about this on the Minecraft wiki already: https://minecraft.gamepedia.com/Talk:Superflat#How_to_set_superflat_preset_for_servers.3F
Answer: This feature is currently (since 1.13) completely broken. Whatever you put in, it's completely ignored. Here is the bug report https://bugs.mojang.com/browse/MC-134900
For now you have to create the world in Singleplayer, then copy it over to the server. Make sure to name the folder "world" (or edit the level-name property).
Update for 1.16: The previous bug was supposedly fixed, but it still doesn't work, instead the server now crashes even with a valid input, because it actively edits the file to contain invalid input for some reason. I created a new report for that: https://bugs.mojang.com/browse/MC-182421
Comment: what did it do before 1.13?
Comment: The regular code, like in the in-game menu, no quotation marks or anything. Example: `generator-settings=minecraft\:bedrock,2*minecraft\:dirt,minecraft\:grass_block;minecraft\:plains;village;` (The backslashes are added automatically if you don't type them.)
Comment: @DedTurtle The latest snapshot has supposedly fixed this bug! I will test it later.
Comment: Well, it was a lot later. :D I tried it now, but it still doesn't work, instead the server does even more nonsense than before: https://bugs.mojang.com/browse/MC-182421