How do you prevent boil-overs?

Question: This is a shill question for Mark Taylor.  I stumbled on his great tip about keeping a spray bottle on hand to prevent boil-overs while looking for advice on yeast re-use.  The spray bottle worked amazingly well.  Ample room in the boil pot is pretty obvious. What other strategies are there?
Answer: I've used FermCap in the last couple of batches.  Seems to work great for preventing that initial boilover.  It still gets foamy, but the foam dissipates much more quickly.  Excellent in starters on the stove top as well.  No noticeable effect in the finished beer.  No problems with head retention, etc.
Answer: If you don't have a spray bottle or hose nearby, you can stir the wort with a big spoon or paddle and that will break up the foam. Just be careful not to burn yourself!
Answer: Giant Pot
I use a 20 gallon pot for a typical 12.5 gallon wort boil.
Sometimes I have a spray bottle
Answer: I keep a very close eye on the foam level during the first 10 minutes of the boil and am very ready to kill the heat if need be.  Recently I've been boiling with my pot about 2" from the rim at the start of the boil and haven't boiled over... yet.  Brewing on a gas range (as opposed to electric) really provides for a lot of control over the heat input.  With gas, when you kill the heat, it's killed, unlike an electric coil stove where you kill the heat and it starts to cool off.
When adding hops, I drop in one or two to test the water - er, wort - before going all-in.  Hops provide a lot of nucleation sites, so adding them quickly could cause there to be a ton of foam when there was no foam seconds earlier.
Answer: Similar to the spray bottle...I keep a glass of cool water nearby. If the foam starts rising I dump a little in. Settles things down nicely.
Answer: Adding a few hops before the boil starts will control the foam up. I add 3-6 pellets from my first bittering addition. I don't remember the science behind it (explained on Basic Brewing Radio), but something with the oils of the hops helps to reduce the foam. Also blowing on it......
Comment: +1 for blowing on it.  I did this in a panic once and was amazed that it worked.  Don't know if it's a function of my pot shape (it's wider than it is tall) but all it takes is blowing on it for 2-3 seconds and it's under control.  When I had a smaller pot I could snatch it off the heat fairly easily, but now I'm doing full-volume boils in a 10G pot so it'd be a bit more challenging.
Comment: I have also had luck with blowing. My pot is taller than wide.  I am thinking of trying to automate the boil with an accoustic distance measure that would trigger a hair-drier (on cold setting), all powered by a RPi
Answer: Fermcap S is far and away the best solution. Use as directed during the boil. You can also use it in the fermenter to prevent a large krausen from overwhelming your airlock, but you will need to adjust your IBU's as it will reduce hop utilization during fermentation.
You can also add a drop or two to your starters to prevent boil overs when preparing them.
Answer: I now use fermcap, but I found a little 5 inch fan directed right at the surface works great.
Answer: I brew on my stove which is right next to a window.  I open the window, turn on the vent fan, and when boilover is imminent, I'll blow on the foam, and that reduces the foam quite quickly.  Granted I've only done this with extract and specialty grain, so it may not work in all-grain, but I'd recommend it for a try.
Answer: The first defense for me is the spray bottle but frankly the only times I've had boil-overs is when I'm not paying attention. So, first on my list of boil over remedies is paying attention as the boil nears 212f.
mark
Beer Diary...
Answer: I just pick the pot up off the stove if a boil-over seems imminent. Gas or electric, that immediately stops any boil. If you're not in the vicinity to notice a pending boil-over, then I don't know what you can do beyond buying a bigger pot or using FermCap.
Comment: This could be extraordinarily dangerous for anyone doing anything more than a 2-3 gallon boil, and not advisable for even those.
Comment: Really? I regularly do this for 3-4 gallon boils in a 5.5 gallon pot. Any rising froth *immediately* recedes once heat is not being applied, so it's not going to get on my hands. If it seems too heavy, one can set it down on the adjacent burner.
Comment: My concern with lifting my 20 gallon pot when it's full to 13 gallons is the integrity of the handles and their attachment to the pot.  If one should break, I'd have boiling liquid everywhere and probably some severe burns.  As pots get smaller, this is less of a concern.
Answer: I have an oscillating fan that I put on low that blows right on my keggle. Keeps the foam down, but you will end up with more loss of volume, so be prepared for that with some distilled water to top off with if needed.
Answer: I find that a fan pointed at my brew helps prevent boiling. Similar to the gentlemen that blows on his brew, but this way you don't have to worry about lung capacity. One caveat: I'm pretty sure this will increase your boiloff rate, so you'll want to compensate accordingly.

How do you prevent boil-overs?


Disqus style plugin for contact forms

Question: I've been using a combination of Swifmailer and jQuery to add a website contact form to sites that aren't using a cms, but the ease of implementing a Disqus module for  comments makes me wonder if an equivalent is available for a contact form? I've looked high and low on the Web, and I still haven't anything that can be used outside of WordPress, Drupal etc or doesn't require heavy configuration on the back end
Answer: You're looking for something like Wufoo forms or its alternatives. Design the form, get embed code, deploy.  Rinse and repeat.

Disqus style plugin for contact forms


Why was the Obscurus in Newt's case staying in a snowscape?

Question: Why was the Obscurus in Newt's case in Fantastic Beasts and Where to Find Them staying in a snowscape? All the other creatures were more or less in their natural environment.
Answer: I think it was a deliberate choice made by the director/writers rather than any hint as to the obscurus' origins.
In the movie we find out that they usually come about when a magical child represses or hides their abilities, usually becoming "infected" with an obscurus.  These are children that are usually unaware of the magical community and are alone, left to deal with their abilities that don't possibly make sense.
When we see the obcurus in Newt case, it's in a solitary, cold, dark environ.  These are physical manifestations of what it can feel to be alone, with no one to help you or guide you through what's happening.
It's a bleak environment because that's what the children infested usually experience.
Answer: The Obscurus that Newt obtained came from Sudan which has no icy/cold areas. As we know, the child will have surpressed their magical 'side' due to societal/family pressures, so my assumption is that Newt provided a completely alien environment for the Obscurial to feel comfortable in.
Any recollection it may have of its old life have been obscured with desolate snow.
Answer: The obscurus is or might still be dangerous, though missing its Obscurial
But we don't really know that, as Graves tells Newt, that there is no use of an Obscurus without its Obscurial when he sentences him in the ministry.
Still it is an uncontrollable force and therefor I guess, that Newt does not want it to roam freely.
Answer: Maybe Newt just wanted to hibernate the Obscurus, for better preservation until he returned home and had a chance to study it.
Comment: Anything to backup your theory


Does it matter when you connect to TOR?

Question: Does it matter when you connect to TOR Network ?  2 cases:
1. You connect to TOR after 10 minutes after you connect to your real facebook/bank/email account. Is it harmfull to connect to TOR as like that ?
2. Second case is it dangerous to connect to TOR at 2:00AM-5:00AM when most of people in your state does still sleep and are not online ?
Answer: Somehow it matters, but not fatal. Here are your two cases for a start:

You have connected to Tor after using an authorized page. If your actions you do perform through Tor can be linked with your profile - it's a guess-hint, that it can be you, but not a proof: tor's traffic is 3-times encrypted, at least. If you're using something like Facebook that does have a Tor entrance and making all the precautions like acting through Tor from a separate VM with another login not explicitly linked to the login you've used without Tor - there's no risk at all, except a very vague guess.
It was a concern 10+ years ago, but not now: the global village of Internet is having party 24-7-365 around the globe, so there will be not a significant drop of network activities so they can be inspected deeper. However, a VM and not-linked profiles inside Tor and outside are "the must" and still in power.

However, if you are 100% accurate in using separate temporary VM's and profiles for in-tor activities and want to be completely free of any corellation-related analysis techniques by time - just buy an OrangePI or any Allwinner H3 based SBC and run your Tor node 24-7-365, so as you'll switch to Tor inside your LAN no one will be able to even guess.
Answer:
It shouldn't matter if you connect to your Facebook/email/bank in another browser (e.g. Chrome, Firefox) after using Tor, or vice versa. You may be de-anonymized if you connect to your Facebook account while using Tor.
That depends, but I don't think so. Using the internet isn't very uncommon at that time, so I don't see why using Tor would be any any more suspicious.
Answer: What is dangerous can be case by case specific or even country by country specific. I am gonna write some thoughts.

If you separate the life between real world browser operation (bank, Facebook etc) and Tor browser, I don't see any danger, just by using Tor browser few minutes before/after using normal browser. But if you mix them, then don't expect anonymity. For example download some images using Tor browser (e.g. by using hidden services) and paying for them and then publish them on Facebook can clearly connect you (as real person from Facebook) with someone buying stuff (you as Tor user). Separate the life is essential, and of course don't do anything outrageous.
For example user is living in suppressive country and living in small town like 10000 people and using Tor to upload some video of corrupted mayor to some web site. Because of using Tor it is not possible to say what has actually been uploaded, because Tor traffic is encrypted. But ISP can know who did connect to Tor network (by monitoring entry nodes) and how many data was transfered (how many bytes). In small town lets say at night at 4 AM five users where connected to Tor network. Four of them were just reading some news web sites, so very few bytes where transfered, but one user (you) has uploaded a lot of data (video file). You can become suspect because ISP knows you are the only one using Tor and uploading huge amount of data. In suppressive regime police may arrest you and torture you to admit you have uploaded the video. So just by using basic statistics and you may get out of the crowd. Police may have also other info about you, like you are the one being on a lot of protests etc. They may link police data with simple data usage statistics.
Another real time sample was few years back. Some student didn't learn and on the day of exam by using Tor and anonymous mail he sent a (false) bomb alert to school administrators in hope whole exams would be canceled and he would have enough time to prepare to next time exams will gonna happen. Exams were canceled, success by the student. But police made an investigation. They made some assumptions, like it is hight probability the alert was sent by student, because it was an exams day. They searched public university computer rooms to find out who was using computers at the time when mail was send. They got list of users using computers and by police work interrogation got to few potential suspects. Now eliminate all the students that are not well computer literate, students with good grades not having an interest of an incident, students who professors say it is a reliable person etc and the list shrinks pretty tight. With few police tricks, clever questioning etc they found out which student sent the mail. You see Tor and anonymous mail is not always enough. By using only police work, student was caught.
Using public places like public pub, library etc and using Tor may seem save. But using the same places, day after day, and some employee may remember there was one girl with fanny cap using her own laptop many days in a role. Nobody knows what she was doing (like using Tor), but they remembered her and asking around the visitors of pub/library and someone may know her. By using routines, you may get out of the crowd.
Lets say some thief in a shop steals Rolex (expensive watch). What is he going to do? Walking around in shop for half an hour or just get out of the shop without a panic but as soon as possible. There is a link crime has happened and thief escaped. Now imagine one hundred users are using Tor on some area and some action is performed like posting some post on forum that reveals corruption and after posting user disconnects from the Tor network. Similar logic like with Rolex, end-user accomplished the task and just see no point of being in the same place (shop or Tor), so disconnects. Now police just has to know when post was posted on forum, get confirmation from forum's web site administrator the user was using Tor exit node and needs to get data from ISP which users of Tor network (using Tor entry nodes) where disconnected from the Tor network at the time of publishing of forum post. Some basic psychological profiling and list of potential candidates shrinks dramatically. Not only the specific time, but specific psychological profiling can reveal some crucial lead.

To recap:

Mixing data from Tor usage and real time usage of normal browser can de-anonymize you.
Basic statistical analysis, can reveal some data, when, who and how much data were transfered and may make user unique and so de-anonymized.
Doing something really unique in real world can by mere police work de-anonymize you.
Doing something repetitive in real world and people can remember you and so de-anonymize you.
Basic human behavior can profile user enough to be de-anonymized.

There can be plenty of other samples, so that is why reading Tor documentation strongly suggests to change your HABITS as essential part of anonymity.

Does it matter when you connect to TOR?


Are there any universal rules for bibliographic references recognised all over the world?

Question: There seem to exist many bibliographic reference styles and many universities have their own guidelines too. I wonder, whether there exist any universal guidelines for formatting bibliographic references in publications?
Answer: There is no truly "universal" system—that's why packages like EndNote and BibTex both come with hundreds or even thousands of different bibliography styles.
That said, there are some common approaches—the Modern Language Association and Harvard formats are quite common in the humanities. The sciences have more widely spread systems, but I think the most common I've seen is the "abbreviated style," containing authors, journal, volume and page info and year. (There are some variations within that style based on different publishers, and some publishers, like ACS, are now starting to take advantage of electronic distribution by including full titles.)
Comment: The link to MLA seems to be down.
Answer: The answer is no. Within fields, there are often a single style which makes some approaches and components more common or even that makes a single style dominant.
Get yourself some software like BibTex, EndNote, Zotero (my personal favorite), or similar so that you can simply rely on someone else to automate importing the data into a database and outputting according to whatever rules a particular journal or venue requires.
Comment: This is already contained in Benjamin's answer, but let me stress it once more. **You shouldn't edit bibliography entries by hand**. It is time-consuming and error-prone. There is software for doing that. It might take a little while to learn how to use it, but it is extremely beneficial in the long run.
Answer: As aeismail said, there are no truly universal rules and the bibliographic reference styles differ across scientific disciplines, and even within these there is often large variation. So normally, you need to consider the journal/conference/... the publication you are writing is aimed at and consult their rules. Most of the time, you will find quite strict requirements articulated in the venue's "submission guidelines", or "author's corner" sections - usually on their website. If still not sure, contact the responsible editors/PC chairs to advise you.
Answer: As everyone says, there are no universal systems, although there are a few very popular systems. Of course you should use reference software, but if you are asking which style you should use for general purpose citations outside of publishing, I would just pick one of the most popular, depending on your discipline.

Chicago style seems flexible and perhaps the least field specific.
APA style is popular in the life sciences and psychology, of course. But, I don't know if it is so popular in the humanities.
MLA style seems to be the most popular in the humanities.

If you are not instructed to use a specific one, all of them give the necessary information in a bibliography/reference list format (that is, the full title, authors, dates). I think the issue that might be field specific is in-text citations, but that is not your question. If you pick one and use it consistently in any given document, I am certain it will be internationally understood.
Keep in mind you do not need to learn all the details- just select the option in the software and make sure any imported references (from old PDF's, etc.) are correct. I like Mendeley.


Application Launcher for Hyper-V Server

Question: We are currently in the process of setting up a HyperV R2 Server machine. Though there's not a lot we need to do wihtin the HyperV Server itself, the command line is sure minimalistic.
There are a few administrative / Hardware Monitoring tools that we want to run on he machine itself (accessed through remote desktop).
I am looking for a simple program/application launcher where we can hook up these maintenance tools (and one to open a new cmd.exe window in case I habitually close the one I'm working in!)
However, all tools I tried by now more or less assume explorer is present, and fail in different ways. Before I go and write a simple one myself, any recommendations?
Answer: Finally wrote my own :)
Simple, but does the job.

Application Launcher for Hyper-V Server


What is the purpose of an FFT filter?

Question: I've used the built in FFT filter in Adobe Audition to get some vocals sounding like they're coming from a police radio, and while the black box worked, I'm just curious as to what the FFT filter is actually for, and what differentiates it from an equalizer? What cases calls for one verses the other?
Answer: An equalizer is a combination of filters with different shapes that you adjust in some constrained way.
The FFT filter is based on the Fast Fourier Transform, which is a different way of manipulating signals. It can be viewed as having a direct control of the amplitudes of a selected number of bands (e.g. 2048 bands) in the frequency domain. In other words, it's a lot more precise type of equalization. It can be used to get those vocoder-like filtering effects as well as for noise reduction or very precise equalization. As it involves heavier calculation, it has a considerably larger latency and can produce unintentional processing artifacts in real-time use.
Use an equalizer as you'd use it normally.
Use FFT equalization for getting more precision that an EQ gives, for correcting very small frequency areas (e.g. supressing noisy parts or very small peaks), for performing equalization of some custom shape that your EQ cannot do or creating a fine-tuned, static filtered sound.
Comment: http://www.cheatography.com/fredv/cheat-sheets/eq-tips/  has some good tips
Answer: The algorithm is different. Typical eq works in a simmilar way that analog circuits does, but in a digital domain. There are FIR (finitive impulse response) and IIR (infinitive impulse response) filters, not going to much in technical details.
FFT filter makes fourier transforms of the sound to frequency domain, where you can easily acces distinctive frequency bins and the amplitude of each frequency can easily be changed, and after that - inverse fourier transform is made to go back to time domain.
Answer: An "FFT filter" is not an established term.  The main purpose of FFT is to speed up convolution with an ongoing signal (cf "overlap-add" and "overlap-shift" algorithms), so I expect the "FFT filter" to just be an implementation of a long-response FIR filter that is rather efficient at the price of considerable time lag.  For offline processing, the time lag is not a problem.
A long-response FIR filter can be used as an equalizer of course since an equalizer is a linear system.  However, equalizers tend to rather use IIR filters (preferably minimal-phase) or quadrature mirror filters for their operation, either of which lead to smaller systematic delays than an FIR filter, and they also map nicer to logarithmic frequency scaling which is customary with equalizers used for musical purposes.

What is the purpose of an FFT filter?


The exact value of $\sum_{n=1}^{\infty}\frac{n^2+n+1}{3^n}$

Question: What is the value of :
$$\sum_{n=1}^{\infty}\frac{n^2+n+1}{3^n}$$
Comment: For example here: http://math.stackexchange.com/questions/30732/how-can-i-evaluate-sum-n-1-infty-frac2n3n1
Answer: You have for $|x|<1$
$$ \sum_{k=0}^\infty x^k=\frac{1}{1-x}$$
$$ \sum_{k=0}^\infty kx^k=x\cdot \left(\frac{1}{1-x}\right )'$$
$$ \sum_{k=0}^\infty k^2x^k=x \cdot \left( x \cdot \left( \frac{1}{1-x}\right )'\right )'$$
Replace $x$ with $1/3$ and you will get the result.
Answer: HINT: you may use $e^{kx}$. Then solve the geometrical progression, derive once/twice its both sides and then plug in $x=-\ln(3)$.
Answer: I don't know the exact steps of how to get that, but i figured out that this comes out to be
$\frac 11+\frac 79+\frac {15}{27}+\ldots$
and this link here, gives the solution to be $\frac {11}4$. Refer
WolframAlpha Solution.
Answer: In most practical applications, you can just ask Mathematica, and it will tell you it's $\frac{11}{4}$.
If you want to arrive at the formula in a more rigorous way, you can do the following:
Consider the function $f$: $$f(x) = \frac{1}{1 - x} = \sum_{n=0}^\infty x^n$$
An initial observation is that $f(\frac{1}{3}) = \sum_{n=0}^\infty \frac{1}{3^n}$ so it looks a little like your sum. Now, consider $f'$:
$$f'(x) = \frac{1}{(1 - x)^2} = \sum_{n=1}^\infty n x^{n-1} = \sum_{n=0}^\infty (n+1) x^{n} $$
When you plug in $\frac{1}{3}$ again, you find $f'(\frac{1}{3}) = \sum_{n=0}^\infty \frac{n+1}{3^n}$. Finally, consider $f''$:
$$f''(x) = \frac{2}{(1 - x)^3} = \sum_{n=0}^\infty (n+2)(n+1) x^{n} = \sum_{n=0}^\infty (n^2 + 3n + 2) x^{n}$$
When you plug in $\frac{1}{3}$ once more, you find $f''(\frac{1}{3}) = \sum_{n=0}^\infty \frac{n^2 + 3n + 2}{3^n}$. Now, all you have to do is to express $n^2 + n +1$ as:
$$ n^2 + n + 1 = (n^2 + 3n + 1) - 2 (n+1) + 1 $$
so you get that the sought sum $S$ is:
$$ S = f''\left(\frac{1}{3}\right) - 2 f'\left(\frac{1}{3}\right) - f\left(\frac{1}{3}\right)$$
The remaining computation is not pleasant, but it is definitely doable, and does not involve any new creative ideas.

I was a little too careless: the computation I did was for a sum raging from $n=0$ rather than $n=1$ as in the problem. It is however easy to mend - just subtract the initial term, which is just $\frac{1}{3}$.


Where did the texture fill option go in QGIS 1.9 Master?

Question: In the previous version (1.8) of QGIS you could select to fill a polygon using a PNG or JPG image.  This option seems to have gone from QGIS 1.9 Master.  I can get it by selecting the "Old Symbology" button on the Style tab.  That's OK but surely this option has not been deprecated (or has it)?
Can anybody tell me where the fill by image option has disappeared to because the only other option I appear to have is SVG fill (SVG is very nice, but I also want the flexibility of using a PNG or JPG is that is what I have to hand) - or perhaps the option only exists as the 'old symbology'.  Also, does anybody know if it is intended to only allow filling polygons with SVG as opposed to PNG/JPG in the future?
Thanks
Answer: As far as I know and according to the documentation new symbology only supports SVGs while old symbology only supported JPG, XPM and PNG.
I don't know if PNG/JPG support is currently planned. If there is funding, we'll see it. But such information can be best asked on the mailing list.


SQL Server: Filegrowth options for Data Warehouse database?

Question: I'm creating a database for data warehousing purposes. The database will grow about 10 000 - 100 000 rows in a week (this is a guess). I think that I'll have to go with database file autogrowth, what would be the best options for file growth? 1 megabyte is bad, maybe 100 mb or so? How do you estimate the best options for file growth?
Answer: For autogrowth set the amount to a defined size and not a percentage.  You need to figure out the size of the rows and calculate how much the data will grow.  For example, if your row size is the maximum of 8KB then 10,000 rows of growth will amount to 80MB.  This setting can be used in production but there are many other considerations.  See this article for more details.
http://support.microsoft.com/kb/315512
Answer: Find how much space your tables have by issuing: sp_spaceused 'dbo.TABLE_NAME'
If the cumulated row number is 200,000 rows and 5 MB of space then set up the auto-growth for a month: meaning 100,000 rows * 30 days = 2,5 MB * 30 days = 75 MB. A value rounded to 100 MB up to 300 - 400 is not a huge activity for SQL to manage when allocating the disk space. Check out also if you have instant file initialization. Log file auto-growth needs also to be set to a fixed value because DW processes are Log space consuming even if the Database is in Simple recovery model. 50 - 100 MB would be a reasonable size.
In any case don't leave the default options for both data and log file. This is not very good.


Where do the heavier elements come from?

Question: Partly inspired by this question, the end result of stellar fusion is Iron-56 (eventually, after some decay). Then it explodes. How/where then to the heavier elements come from. The answer here mentioned two colliding stars form gold. What process is taking place to form this gold (and I'd assume the rest of the heavier elements)?
Answer: The processes at work are the r-process and the s-process.
The r-process occurs in supernovae. Under the extreme conditions leading up to it, heavy elements are initially blocked from undergoing beta decay to other elements. If a heavy atom captures a nearby neutron, it can go to a heavier isotope or element. This happens multiple times to an atom, producing heavy elements.

The s-process is slower, and occurs under less dramatic conditions in asymptotic giant branch (AGB) stars - a certain type of red giant. It also uses neutron capture and the subsequent decay of that neutron into a proton. Over thousands of years, atoms climb to become heavier elements. The s-process, though, requires that there already be some heavy elements in existence, unlike the r-process.

For more information, Hyperphysics, this lecture and this German site (in English) are very useful.
Comment: "The r-process occurs in supernovae". Needs revision.
Comment: @RobJeffries You're right; the LIGO data makes that bit out of date. I'll revise it when I have the time to do it right.
Answer: HDE226868's answer is perfectly correct. Just to add the following important information though.
The s-process is limited to elements lighter than lead and produces little peaks of abundance at certain elements along the s-process path - eg. Ba, Sr, Eu, Y. These are often called s-process elements. All the elements heavier than lead are produced by explosive r-process nucleosynthesis in supernova explosions, colliding neutron stars etc.
The split between r-process and s-process production of heavier than iron (peak) elements is about 50:50. ie They weren't mainly made in supernovae, which is a frequent, incorrect claim.
An update is also in order regarding the site of the r-process. In the past it has been thought that most of the r-processing occurs in the early stages of a supernova explosion. However, theoretical models have really struggled to get the environment as neutron-rich as required to produce the heavier elements - certainly those up around gold, platinum, osmium etc.
In the last few years it has become more popular to think that merging neutron star are the main site of the r-process. This hypothesis received a boost with the observation of a gravitational wave source source that appeared to be that of a merging neutron star system coinciding with a kilonova explosion seen in gamma rays, visible and infrared light. The infrared spectrum of the decaying light from this explosion betrays the presence of "lanthanide" elements that are produced in the r-process.
Note however that the rate and yield of such events is highly uncertain. There is plenty of good work which suggests that rare types of core-collapse supernovae (aka "collapsars") are still in fact the dominant source of r-process elements in the Milky Way (Siegel 2019).
The relative contributions of various sites to the r-process remains an unsettled matter. You could also read my answers on this topic in Physics Stack Exchange.
https://physics.stackexchange.com/questions/231981/heavy-element-production-from-supernova
https://physics.stackexchange.com/questions/7131/origin-of-elements-heavier-than-iron-fe


How do the Noble Families work in Bleach?

Question: In Bleach, there are Four Noble Families of the Soul Society. I know that people can have children in the Soul Society. However, is whether you are a part of the Noble family based on whether you were born into that family in the real world or in the Soul Society? For example, if you are from the original line of the Kuchiki family (in the real world) and you died, would you become part of the Noble Family?
Answer: I do not think they went deeper into the noble houses, so I believe there is no current information available about "How to become a noble". All the currently available information on the 4 noble houses can be found here.
There they also state:

The Noble Houses of Soul Society have an unclear role in the culture, social and governmental aspects of that dimensions existence.

Some speculation from my side: I think that they were either appointed by the Soul King or the Central 46. And I also believe the divisions are involved in this.

There is reason to believe that the captaincy of the 6th Division runs in the Kuchiki family, as at least two members, both of them were family heads, have held the title captain and two other known members have been lieutenant and 3rd seat respectively.

This part is just speculation though.


What do I need to do to secure log-in and registration for my website?

Question: What security features do I need to have in-place to ensure that my website log-in and registration forms are secure?
Comment: http://en.wikipedia.org/wiki/Cross-site_request_forgery
Answer: CSRF - You need to have protection in place to prevent cross site request forgery - or requests to login, signup, or other actions from other sites. This can be used to trick users into performing actions they didn't intend to.
CAPTCHA on signup - It's often recommended to use a CAPTCHA on your sigh-up form to reduce automated signups. How important this is depends on your threat model.
Secure login - The login needs to happen over HTTPS to reduce the risk of the user's credentials being captured via a MiTM attack.
Cookies - While login over HTTPS should be seen as a minimum, everything else really should be over SSL as well to protect the cookies (remember Firesheep?). Though just using SSL isn't enough, you need to set the Secure flag and HttpOnly flag whenever possible.
Email Confirmation - You need to make sure that you verify a user's email address as part of the sign-up process (I'd suggest not letting them login until it's confirmed). You'll need to have this for use in password resets.
Bruteforce protection - You need to protect against an attacker bruteforcing user accounts. There are various ways to do this, locking accounts (which can be used as a DoS attack by locking out large number of users), limiting failed attempts from a given IP (either via ban, or additional CAPTCHA). There are pros and cons to each method, but it's important that you have some form of protection in place.
Secure password reset - You need to make sure that you have a secure method for resetting passwords. This one is more complicated than most people think, and is easy to get wrong (as Apple recently found). The biggest risk is that an attacker finds a way to abuse the feature to reset accounts that they don't own.
I'd strongly suggest that you read the OWSAP Authentication Cheat Sheet, it goes into detail on these and many other potential issues; and as always, when building new systems, it's a good time to take another look at the OWASP Top 10 and make sure you have taken the proper precautions.
Comment: I hope you consider [this CAPTCHA](http://xkcd.com/810/)...
Answer: Adding to Adam's answer I would like to say that according to  OWASP Top 10 Application
Security Risks–2013 the top three vulnerabilities are Injection,Flaws in Authentication mechanism/session management and XSS.

Authentication and session management is a very broad topic but OWASP has a number of cheat sheets and guides whose links can be found in the above pdf.
The other two vulnerabilities Injection and XSS are generally a result of not validating the user input before generating the dynamic content (XSS) or before using it in a DB query (injection).
To prevent from Injection all the user input parameters must be validated (server-side) before using them in queries.
Prevention against XSS : see this
Answer: About the cookie:
If you use the cookie for the login process it is important to save the cookie information in your database (MySQL for example) so if an user makes the logout the cookie information will be deleted from database and the cookie won't be longer valid. It's is important, because if a hacker steals the cookie then he can access to your account!
Another parallel solution:
For protect your login page you can use this service Colobe
It is a free service that protects your pages by any brute force attack.
Anyway Colobe requires the PHP in your server.
It is very cool because colobe is a dynamic service that learn during the time and builds a global blacklist of the botnet networks and pirate servers that generate those attacks.
N.B. Colobe is a project of mine.
Comment: and how do you protect me with colobe ? only by collecting blacklist ? your website is not informative enough to show the customers what you can do ... you should make it more informative and infographic
Comment: Thank you for your feedback ^_^ I will improve the informations. Anyway, yes, it's "only" a blacklist, you can also view the login statistics.
Comment: Here there is the documentation if you are interested: https://colobe.net/?wh=documentation


Paleogeographic Map

Question: How do you construct a paleogeographic map with given sedimentary structures as guidelines?
Answer: While we're certainly not going to do your homework for you (and we couldn't anyway, because the map is not legible in the photo you provided), this looks like a fun exercise and a chance to express your creativity.
Your teacher has asked you to draw some paleo geographic features on a map given some sedimentary features that have been plotted for you.
Try to think of how those features are laid down in a sedimentary environment. Are they indicative of land? rivers? ocean?
For example, if there's a point that shows sandstone, there must have been sand laid down in the past.
Then, picture how the features that your teacher wants would have contributed to that deposition, and where they would have been in relation to one another while the sediments were being deposited.
Finally, you can draw the features on the map in between or around the provided points, based upon how you decided that would happen.

Paleogeographic Map


How difficult is it to eat and drink during ramadan in Thailand and Malaysia?

Question: Next month I'll visit Thailand and (maybe) Malaysia. From 19th july to 20th august muslim countries celebrate the ramadan. When we were in Egypt, we didn't perceive that we were in ramadan, but in Dubai we had a lot of problems to eat or drink. So I would like to know which limitations or how easy-difficult is to eat and drink during ramadan in Thailand and Malaysia.
Answer: Having been to both during Ramadan:
In all reasonably touristy areas in Thailand, including the southern resort islands, you basically will not notice Ramadan at all -- pretty much everything is open as usual.
Malaysia, though, is a different story.  While you certainly can get drinks and food, most places that stay open do so a little discreetly, with curtains on the windows etc, and you'll want to show respect to people who are fasting by not eating, drinking or smoking in public.  The flip side of the coin is that once the time for buka puasa (breaking the fast) rolls around at sunset, many restaurants will be packed with Muslims, so you may actually want to beat the rush and grab your dinner before 6!   Out in the nearly 100% Malay countryside, though, virtually everything will shut down during the day.
(Anecdote: I once had the slightly surreal experience of walking into a packed KFC in KL Sentral, getting my dinner and sitting down -- only to realize that nobody in the restaurant was touching their food.  So I took the cue, waited for a few minutes until the call to prayer started, and then joined the ravenous horde in tucking into my fried chicken.)
The other travel glitch to beware of is that the end of Ramadan (Eid ul-Fitr, or Hari Raya Puasa in Malay) is the local equivalent of Christmas, when everybody takes time off and goes back to their families.  This means most transportation is fully booked for several days and even the traffic jams are legendary.  Plan ahead so you can avoid travel at this time.
Comment: +1. To add to what @jpatokal says, it also depends on what part of town or what the ethnic majority of that town is. Chinatown in KL or towns with higher majority of ethnic Chinese such as Ipoh, you can often find Chinese-owned restaurants that are slightly more lax about Ramadan rules than others.
Answer: In Thailand, it depends on where you'll be going. Anywhere from Bangkok northwards, you won't notice anything in relation to Ramadan. There's a significant muslim presence in the south of Thailand (the sliver of land that borders Malaysia), but I don't know to what extent Ramadan celebrations there spill over into public life.
Malaysia is religiously tolerant, simply because there are so many different communities in that country. So, in the big cities, you might find areas where Ramadan celebrations are hard to avoid, while there will be others where life will go on as usual.
Small towns could be markedly different, but I have no info on that, sadly.
Comment: In small Malaysian towns and villages do not think about eating or drinking during the day...
Comment: The yellow bar of death :( I was about to click "Post"
Comment: Thailand, you won't know it is Ramadan, and most thais won't either. Malaysia, they practice the sharia  (islamic law) even when it is not ramadan...skip malaisia altogether. take a flight to Bali for instance, though indonesia is muslim they are more relaxed and even more so in Bali which is technically dominantly hindu.
Answer: Thailand is over 80% Theravada Buddhist. I have lived here for years and the average Thai would not even know what Ramadan is - or at least would not think it concerns them in any way. There are pockets of Muslims communities around Thailand.
In CM there is a fair sized community, they will honour Ramadan tradition, but are not at all extreme - so again, even if you stayed in the middle of their community you would not notice much (maybe a lack of food carts that day, but plenty around the corner!)
In the south, especially very far south around Yala, Narathiwat, Songkhla and Satun, the Muslims are known to be more extreme in their views (Malaysian) - but it is very doubtful you will be holidaying anywhere near these areas (if so Ramadan would be the least of your worried - not getting blown to pieces at the local 7-11 would be higher on the list!)
Comment: What does extremity have to do with anything? Also, are 7-11's being blown up a common occurrence in southern Thailand?
Comment: Thai Muslims are generally mild and tolerant (I would think this makes sense given the vast majority of Buddhists in this Buddhist country). However, the far south (not just south - but the final few provinces before the Malaysian border) are know to be the opposite. There are bombings, murders and attacks quite frequently - most are not even reported in the national (let alone international) media. Several times a year there seems to be something "news worthy" - this summer it has been a series of bombings (same last summer actually) - we have also had schools and temples bombed/burned...
Comment: teachers and monks attacked and murdered (coupke of years ag a few monks were beheaded - one was only a child of around 10 if I remember right). Most countries have warnings against travelling to the far south - for good reason. The army is installed there perminantly. It stays south though and there have to date been no troubles further north (a few rumours and fears of course).
Comment: @Wolf5370 When I went on holiday to Phuket, the majority of Thai people were Muslims. I guessing that this might be true of other Thai islands as well but not the mainland.


Buying Bitcoin Cash

Question: Hopefully my question is relevant based on my understanding I received during the tour. I would like to buy Bitcoin cash. I have GDAX/Blockchain account but Bitcoin cash is not available to buy on those sites. Can you advice? Thank you
Answer: You can buy BCH on other sites, such as https://www.kraken.com.
I hope it helps,
David
Answer: There are many altcoin exchanges such as Bitfinex that you can buy the altcoin bitcoin cash, but you should be warey that the price is being heavily manipulated by the project owners

Buying Bitcoin Cash


How to compute for basis adjusted forward rate?

Question: To give you a brief background, I'm valuing a fixed-for-float Interest Rate Swap (IRS) using Bloomberg. I put in a notional amount in (USD) and a assigned 6MO USD LIBOR as the reference index for the floating leg. I want to know how Bloomberg computed for the floating rates it used to compute for the floating cash flows and they told me that: 6MO USD LIBOR forward rate is computed using 3MO USD Swap curve then they did a basis adjustment to come up with basis adjusted forward rate. I would like to know how to compute for this basis adjusted forward rate? Thank you.
Answer: First a 3M Libor curve is built (using futures and 3M Libor swaps) and then they try to compute the adequate spread implied in the market between 3M and 6M LIBOR forwards.
For calculating this spread, they use tenor basis swaps like 3M-6M LIBOR basis swaps traded in the market. The 6M LIBOR is such that:
1) it's spread with 3M LIBOR  matches the observed spread between 3M Libor forward and 6M Libor forward in 3-6M tenor basis swaps (traded OTC). This is mostly for shorter end of the curve.
2) The 6M forward obtained matches the 6M LIBOR swaps traded in the market. This is for the longer end of the curve.
Apply the implied spread on top of the 3M LIBOR forward rate to get the 6M LIBOR .


When is the index actually created?

Question: I have noticed that even on huge tables with millions of records when I do a CREATE INDEX the index is created immediately (I get the console back in nsecs).
Why is this? Doesn't it create the B-Tree with the table data at that point? I can only assume not due to the immediate return of the CREATE INDEX.
But then how is the index created? On each access?
Comment: By the way, innodb, despite the SQL interface saying BTREE, uses B+Trees.
Answer: Secondary index creation on innodb has been much faster since MySQL 5.1 + InnoDB plugin or MySQL 5.5. In fact, we refer to this feature as "fast index creation". If we don't touch the primary key, it only creates an additional structure and it only has to read the current values, without modifying the table data. Assuming you have enough memory, if the data pages are in memory and the index also fits into memory- this will be a memory-only operation, so potentially very fast. But the index will be ready to be used as soon as the process ends. In the background (after you get control back to the console), it will write the new pages to disk whenever it can. It is also dependent on how much data fragmentation you have in that particular tablespace. None of this can lead to losing data due to the transaction log (which is on disk).
But you are completely right by saying that some changes on secondary indexes are done in the background: it is called Change buffer, but it is used when modifying data records.
I must say that in my experience, InnoDB index creation is not as fast as it could :-), specially on very busy servers. However, starting with 5.6, creating secondary indexes is completely online (writers to that table are not blocked), which is a very nice improvement indeed.

When is the index actually created?


IP address of an iPhone

Question: Recently I logged on to my bank account via the Chase app on my iPhone. I received a message that another device was currently logged on to my account and "would I like to end the session"? Of course, I ended it.  I went directly to Chase Bank and spoke with their security department. There was another user logged on from another iPhone. All they could give me was their IP address. Is there any way to track who this was? And do iPhones use random IP addresses depending on the location and whether WiFi is available or not?
Comment: Thanks Mr. Flagrum for your explanation. But there need to be some improvement in answer. - If its a status IP address then also you can trace the person by its MAC address which never changes and is unique for each device. You can challenge anybody from this. - You can trace the IMEI from if its a mobile device and can easily catch the person. - As you mentioned above, that if IPV6 is assigned so you might catch a wrong person if translation doesn't happen in IPv4. That's impossible since both have different formats like mentioned below:- IPv4 --> 188.8.131.52
IPv6 --> 347F:485A:AD2B:124C:EF
Answer: There is a possibility that the other iPhone was... yours.
Your IP address is awarded to you by whatever technology provides your Internet access. When you connect over 3G, the IP address comes from your phone company. When you connect over WiFi, you get an IP address from the WiFi access points. The IP addresses can be "dynamic", i.e. it may change over time. Also, each WiFi access point can only give you an IP address that it owns, and most such access points use NAT.
This means that when you connect to WiFi access point A, you get a "private IP" and all your traffic is seen, from the outside (and in particular from the bank server), as coming from A's own unique IP address. If you then use this nifty feature of mobile phones, namely their mobility (you can walk in the street with a phone, there is no wire to deal with), then you may walk away from the range of WiFi access point A, and enter a zone covered by WiFi access point B. Your iPhone, being a smart phone, will automatically connect to B. But then, your requests will come out with B's IP address, not A. Nothing will warn the bank server that your phone has disconnected from WiFi access point A; all that the bank sees is a request bearing B's IP address, whereas a few minutes before they got a request bearing A's IP address. From their point of view, this means that there are two "connected" clients, and they warn about that.
(The technical point here is that Web requests are that: requests. You do not have a direct, permanent connection between your phone and the bank; this is not a phone call. This is more akin to mailing: your phone sends a request, the server sends back a response, but there is no way for the bank to know if you relocated elsewhere since the last request you sent.)
Comment: Question Mr. Leek.....if I had not logged on to my account that day....and then logged on for the 1st time around 3pm and the "other device" had been logged on at 2:48 pm.....could it have still been mine? I have two separate IP addresses....the one at 2:48 and the one at 3:00.  Please forgive me not technically inclined.
Comment: It really depends on whether "around 3pm" could be 2:48 pm or not. From the server, they only see individual requests, but requests are sent only when you do something (click on a button, follow a link), not when you just look at the page. It is hard to tell more with the available information. In any case, changing your authentication password would not harm here (in case that password was stolen, it would "evict" the thief).
Comment: @Paige Now what was your IP and the other IP you were told? Is it possible you didn't log off the day before?
Answer: Essentially you just need to contact the police. They are the only people who are likely to be able to help you. That said, some police respond well if you can provide a little more information about your attacker.
The IP address you have will be either the address given to the GSM transceiver in the phone (if they were using 3G for example), or the address of the gateway of a WiFi network that the attacker's phone was connected to.
Which it is is quite easy to find out; you can use an online whois service to discover which ISP the address is registered to. If it is a mobile telecomms provider, then they were using GSM on a SIM card issued by that provider, otherwise they were on WiFi.
Either way, you can proceed by contacting the ISP in question to let them know that their network is being used for fraudulent purposes. They will be able to lookup which ISP account the address was assigned to at the time in question, however this is not information they would give to you, only the police, and typically only once a judge orders them to.
Comment: +1 for mentioning the police up front. In The Netherlands, that would be 1 CIOT lookup and they'd know the name and address of the person owning it. That doesn't mean this person did it, but that's already more than you could do yourself.
Answer: The best you can do (without the assistance of the ISP that is) is track the general location of where that iPhone was, and who the ISP is.
You can do this with any IP Whois tool, however I will caution that it may lead you to a dead end. If the iPhone was connected to a WiFi network the IP address will be different than if it was connected to the carriers 3G / LTE Network. Alternatively the iPhone could have been connected to a VPN or used a proxy, in which case you're left with another dead end as far as tracking the user is concerned.
Track the IP address and see where that lands you - you won't be able to do much without the police as ISPs don't hand over personal details without police warrants. Be prepared that this might be an uphill battle for you.
Good luck.
Answer: Here is how this really works.

Where ever you are your IP address on a Smart phone may, or may not change.  This purely depends on the carrier and or provider of said access.  Some will give you a static Ip, others will give you a Dynamic IP.  Static does not change, Dynamic does.  (If I am remembering right I am very tired.)

So, lets say you retrieved the IP address from your bank of the other phone that was logged in.  Now we move onto 2.
2A.  If its Dynamic, you might be out of luck, because as the person with the other phone or device moves around, their ip address will change based upon whatever cell tower's IP address they are connected to at the time they are logged into your account.
2B.  If its static, now you are in luck, because wherever that smart phone or device is located, the towers it connects to will then relay the data to the carrier's servers which will allocate the same IP address no matter where the phone or device is.
REMEMBER:  If the phone carrier is using IPV6 allocations then you will have to translate it back to IP4, which might be on a "as per need" use allocation.  So you might hit someone elses phone who was not the individual logged into your account.

If the scenario is 2B, now we have something to work with.  You can "trace route" that IP address, and see what its distance from you actually is, it will be in miliseconds.  Remember you will be traveling over lines, that are either on poles or in the ground, so you need to know the general position of travel of your packets down those lines.

Now, if they are connected to, lets say, star bucks, wireless instead of directly to the carrier, you will be able to determine that using a simple Who Is Search.  But then you have to find the person, go where they are, catch them doing it, and convince the cops you are right.  There, are, other things you could do, but I am not going to discuss that with you or anyone else.

Here is your last option, on scenario 2B.  You can get ahold of that phones carrier or provider, compile you evidence before hand of course, then call them, and file a complaint, both over email, in voice, and in writing.  It is likely that if you can prove your case, that they will permanently Ban that user, and that phone from their service to avoid future problems.

Good Luck!

IP address of an iPhone


Armory client shows transaction unconfirmed

Question: I am new to btc and am using the Armory client. Yesterday I transferred some btc to wallet from my MtGox account. The wallet showed the btc received within minutes, but, after 12 hours it still shows as 'unconfirmed' in my Armory wallet, so my spendable funds is 0. Also, the status shows as not yet in the blockchain. So there is no block number assigned.
However, looking at the referenced transaction block on blockchain, I see my amount with another transaction, the block has 109 confirmations, and a block number. So I have two questions.
1) So it appears my Armory client isn't reflecting the block chain? What should I do? Will restarting the client cause me to lose anything? Will it update?
2) I am under the impression that it's the recipient who pays the transfer fees. I didn't set a fee when I sent the money, but my home wallet has a default fee built in, is that all I need? Can I lose transactions if the go unconfirmed?
3) What recourse do I have. I basically sent myself the bitcoin, but it appears I cannot spend them.
Thank you
Answer: You should launch it with the <code>-rescan</code> option, to rescan the blockchain for missed transactions and confirmations.


Best way to clean copper pots?

Question: I got an awesome set of copper pots as a wedding gift. They are amazing, but the direct flame has created aggressive burn marks and discoloring. I'm aware that this is always going to occur. Is there a way to restore the original color?
Comment: If you are going to use them, shining them all the time will be very tedious - and might eventually make you less prone to reach for one .vs. a pan you won't have to polish after each use. I say let the polish go unless you're going to use them as wallhangers.
Comment: I love using them. High quality, but I figured I could clean them every couple months just for appearance purposes. A pride thing I guess. Thanks for the recommendation though, more than likely what I will do!
Answer: First you need salt, then you need an acid. Some methods use flour because the paste with the flour is easier to control. For acid you can use vinegar or lemon juice; citric acid would probably work beautifully (from Ecnerwal in comments). One of the videos I'm posting here uses white wine vinegar. Their salt is probably Maldon Sea Salt Flakes, which would be even more ridiculous. Lemon juice or plain vinegar along with salt (coarser is probably somewhat better) are all you need to make your pans gorgeous.
Here's a video where he uses 1 TBS flour, 1 tsp salt, and enough vinegar to make a paste.
Dab it on and let it sit for 30 minutes.

Then wipe and rinse off the paste. Voilà!

This is another video where he uses white wine vinegar {rolls eyes} and coarse salt. He doesn't use the flour, and the technique is a bit clumsier without it. It's pretty much the same concept as the first video. He goes a bit further and uses a wee bit of elbow grease with a vinegar soaked scrubby sponge on the burn mark on the base of the pan.

Many other sources on the Internet, including The Kitchn use lemon juice or cut lemons instead of vinegar. It doesn't seem to make much difference, all of the related methods work.
Comment: Straight citric acid (if you can find it - I finally tracked it down at my "local" Asian grocery store, 45 miles away...) is probably the most cost efficient acid source - far cheaper than lemon juice, (or lemons - what a waste) and cheaper per "amount of acidity" than vinegar. The untreated part of the top pan looks just like mom's always did, and it's stable that way. Probably also just a hair better at heating, too, come to think of it (not shiny, heat is not reflected)
Comment: @Ecnerwal, I have no doubt that citric acid would work beautifully. They sell  citric acid at my grocery store in the bulk aisle. White vinegar from a jug and ordinary salt is pretty trivial, though. And the last time I bought citric acid, I was surprised how expensive it was. Of course that was in the bulk aisle of my regular grocery store. Answer edited to include citric acid as a possibility.
Answer: Buy a few pounds/kilos of barley malt extract, dissolve it in a LARGE pot of water, boil, immerse your pans, take them out shiny.
Now, what we actually do when making beer is to try and remove any corrosion on the copper bits with an acid (vinegar, a citric acid solution, or "star-san" which is a phosphoric acid based sanitizer) before we plunge the copper (cooling coil, usually) into the pot, since whatever comes off the coil ends up in the beer. But if you are not making beer, that's not a problem. The coil comes out shiny-clean every time. Odds are excellent it would work on your pots/pans as well. Of course, the other food-grade acids we pre-clean with might also work, and be a hair cheaper.
Evidently a common adjunct to the acid cleaning which I was unaware of from the brewing perspective is to mix the acid with salt (not dissolve the salt in it) to use the salt as a mild abrasive in rubbing the copper - it may also contribute chemically but I'm a bit fuzzy on the details.)
Answer: Using a bit of tamarind pulp and scrub, I used to clean the copper vessels. It makes it clean and shiny. Hope this helps.
Wiki

In homes and temples, especially in Buddhist Asian countries, the fruit pulp is used to polish brass shrine statues and lamps, and copper, brass, and bronze utensils. The copper alone or in brass reacts with moist carbon dioxide to gain a green coat of copper carbonate. Tamarind contains tartaric acid, a weak acid that can remove the coat of copper carbonate. Hence, tarnished copper utensils are cleaned with tamarind or lime, another acidic fruit.

Best way to clean copper pots?


Should one say amen to an unnecessary bracha made by a child on the autism spectrum?

Question: If a very verbal (often too verbal) 12 year old child on the autism spectrum has trouble speaking appropriately and particularly likes to say a bracha when he wants to and not necessarily when it's needed (e.g., he very clearly knows that you don't generally say a bracha on food eaten in the course of a meal where you've said hamotzi on bread, yet he often insists on saying a bracha anyway) and then gets very upset when others don't say amen because is was an unnecessary bracha, should those who hear the bracha say amen anyway?  Is it correct that you don't say amen if a bracha wasn't supposed to be said?
Comment: Evie, welcome to Mi Yodeya and thank you for bringing your question here. I'll remind you that you should consult with a competent rabbi before relying on anything you read here. Also, remember that you can always say "Amem" instead if that helps prevent bad feelings. Please consider registering your account to gain access to all the benefits of the site; I look forward to seeing you around!
Comment: It is indeed correct that one may not answer Amen unnecessarily. On the other hand, the Gemara in Shabbos 141b-142a deals with the fact that a child can become ill due to distress over not getting what he wants. I think the answer will depend, to a large degree, on the specific circumstances.
Comment: Related: http://judaism.stackexchange.com/questions/13604/height-of-a-mezuzah-and-children
Comment: Why not just answer "Emen" or "Enen" or something like that?
Comment: related http://judaism.stackexchange.com/q/15922/759
Answer: The Shulchan Aruch writes (OC 215:4):

כל המברך ברכה שאינה צריכה הרי זה נושא שם שמים לשוא, והרי הוא כנשבע לשוא ואסור לענות אחריו אמן.
  Anyone who says an unnecessary blessing has taken God's name in vain and it is forbidden to recite Amen after him.

So it would seem that you are correct in not saying Amen.
As for the educational/parenting aspects, I don't think a definitive general rule can be given, but I think that responding 'Amem' instead will often succeed at calming the child, although that benefit needs to be balanced against the fact that it may come off as encouraging this 'bad' behavior. CYLOR and CYLCP.


What is an appropriate caliber for hunting mule deer?

Question: I am new to hunting and am looking at various options. I am considering doing some hunting for mule deer in Montana. But I am unsure of an appropriate caliber for them. To increase my shooting skills, I practice with an AR-15 in 223 but I have a feeling that this caliber is not good for mule deer. What calibers should I be looking at?
Comment: I know someone who swears by a 12-pounder Napoleon firing grapeshot.
Comment: They're more of an [ambush weapon](https://en.wikipedia.org/wiki/Canon_obusier_de_12), preferably close to a good road. While effective I'd hate to have to carry one deep into the woods.
Answer: In theory you could hunt Mule Deer with .223.  I had friends who hunt boar with .223 and mule dear aren't really any tougher than a boar.  That being said, smaller caliber equals less expansion and kinetic force.  That means you have to be more precise.
If you are new to hunting, I would go with the classic .30-06.  Good range, good ballistics, great range of available rounds/loads.  You can hunt just about any large game in North America with one.  It's a great first rifle for someone getting into large game hunting.
Comment: +1 that's right 30-06 has been the caliber for hunting for more than a hundred years now, the .308 is almost the same thing, good range, reasonable drop, it's drops almost every animal
Comment: +1 for the 30-06. It's one of the more popular rounds so you can find various weight bullets and, being a classic round, it's easy to find at most stores.
Answer: .30 cal is about where big game hunting starts. You could get away with .223 with smaller white tail deer, but you'll increase how often you need to track your deer and that's less humane.
For mule deer, I would stick to .30 or higher. I prefer Springfield 30-06, but that's just my preference. You could really use any .30 or higher.
Comment: Great answer, thank you. I'm disappointed that I can only choose one :(
Answer: My deer rifle is a .270. That is a smaller caliber than what either of the two current answers recommend. My father frequently carries only his .44 magnum bear pistol when hunting bear and/or deer. With my .270 I don't consider shooting bears, and he only considers relatively close shots.
In my opinion there are many firearms that can do the job effectively and humanely (ever wonder why "buck shot" is called "buck shot"). What it really boils down to is what firearms you have, your skill level with those firearms, and the type of hunting you want to do. Obviously these aren't factors that we can evaluate for you.
I agree with both current answers that the 30-06 is a solid firearm for your stated needs. If you don't have one, and you're looking to buy a hunting rifle, that is a great general purpose setup that I would certainly be comfortable recommending. Keep in mind that the real limiting factor is your ability, your comfort, and your understanding of your weapon's limitations. That is always true, and doubly so when engaging a target with deadly intent.
Comment: Great answer, thank you. I'm disappointed that I can only choose one :(
Answer: You don't need a .30 cal. to take Mule Deer. However they are a proven round, and I personally think they are a little easier to clean than smaller bores.
It's generally accepted that a .243 Win is a good starting point.  And for the difference in recoil. You'll probably get much better at shooting starting off with that .243 which is more mild in recoil. .243 is also considered by most to be the smallest cartridge to consider for taking Black Bears as well. Though there are folks who actually take Black Bears with .223 Rem. yeah, crazy, I know.
I personally started off with a .308 Win. And it handles them with authority, given that you've done your job and placed the bullet properly. They do kick pretty darn good though.  I have a prior collarbone injury and shoulder injury, so the buttstock doesn't lay flat against my shoulder when I'm prone, so when practicing after about 40 shots it starts to hurt pretty good and I have to tap-out.
For perspective, I'm relatively new to Hunting. At 45yo in 2014 got the notion in my head I wanted to do it and I wasn't getting any younger, so I'd better get with it. So far I've taken two Mule Deer hunting solo (2015, 2016) about 5 miles in from the vehicle. The 1st buck was with a .308 Win @40yds.
In the .308 Win the Barnes TTSX 168gr bullets worked amazingly well! That first buck got knocked like 10 inches sideways when I hit him at 40yds. A little high and back for a lung shot, but I think part of the energy got him in the spine as well. He pretty much dropped where he was. His front legs kicked for a little bit after, but not his back legs, so I think the spine sustained damage.
The 2nd buck I decided to take with my Marlin .30-30 Win because I hadn't taken game with it yet, and the terrain is brushy/chapparal and the shots are only like 40yds anyway. The shot placement was different on the 2nd one. He was moving and Quartering away quite a bit. The bullet entered at the midline of the body and took out the liver and the opposite side lung. The bullet didn't pass-thru on that one because it got trapped-in behind the scapula. Also the bullet path was probably a good 18 inches total. There was a little bit of tracking. And since it didn't exit, no blood trail. He ran maybe 35yds, but he was hard to see because one side of his antlers was missing. And he blended in soo well with where he dove under a bush.
The .30-30 Win is a pleasure to shoot compared to the .308 Win.  In the .30-30 Win I used the Federal Premium Trophy Copper 150gr. The bullet retained all of its weight and mushroomed textbook fashion.
I bothered to share these two stories if only to note that you should also consider the terrain you will be hunting in. No sense in buying something like a .300 Win Mag if the terrain you're hunting in will never afford you those long distance shots anyway.
If I had it to do over again, I'd probably buy a .243 Win and it would be my everything gun. Varmint loads for coyotes, deer loads for deer/bear.
And oh yeah... if you have to back-pack and hike-in a few miles to your area... get yourself a model with a synthetic stock. You'll end up falling and scratching the darn thing out in the field, I gaurantee it, and the weight savings you'll come to appreciate in no time flat.
Also... don't go cheap on your hunting pack. You need one that can COMFORTABLY carry that weight for quite a ways.
Good Luck. Now go put in the required work!
Answer: If you are a trained shooter and you manage to get the bullet into the right area the caliber is not too important.


American Fact Finder vs ACS from IPUMS

Question: What is the relationship between the data from the Census's American Fact Finder  and the data from IPUMS ACS?
If the data are different, what are the circumstances in which I should use one over the other?
Answer: The aggregate statistics from the ACS Summary File found through the American FactFinder and the data from the IPUMS ACS are both from the ACS microdata.
The ACS Summary File statistics are based on and weighted from the full sample of the ACS microdata.
The IPUMS ACS is a republished (and in my opinion more polished) version of the ACS PUMS that includes some extra information that can be deduced from other available sources such as technical documentation and geographic shapefiles. The ACS PUMS is also a reduced sample of the original ACS microdata. It is meant to be a ~1% sample of the population. If you want exact  numbers, the ACS microdata has 5,454,957 people among 2,487,838 living quarters and the IPUMS ACS has 3,018,308 people among 1,501,119 living quarters.
Comparing the same estimate for the same geography (e.g. the uninsured rate in Kentucky) will yield slightly different numbers between the ACS Summary File and the IPUMS ACS.
If you are searching for statistics, try to rely on the estimates from American FactFinder. If you are searching for specific sub-populations not found in the ACS Summary File through American FactFinder, or are trying to get accurate standard errors for the differences between two estimates, then you might want to use the IPUMS ACS.
Answer: ipums acs and also the census bureau's acs data files have one record per person.  they are microdata, so millions of individual respondents.  american fact finder presents only aggregated statistics.  it's the difference between an online table creator and actually having the original survey data set.
Comment: So I should be able to exactly construct the fact finder tables from the ipums acs using the person weights? What are the fact finder margins of error?
Answer: I will just pick up the margin of error question that gannawag asked in a comment.
Census Bureau uses successive difference replication variance estimation method to produce their standard errors within FactFinder. With PUMS, you need to run your analysis with replicate weights using statistical software that supports them (Stata, R, SAS, SUDAAN; this is pretty much it -- SPSS does not do replicate weights, and I have no clue about other packages).
As far as the FactFinder goes, my guess is that the Census Bureau mass-produces the margins of error for the Summary Files, and then aggregates them for other levels of geography, rather than running them from scratch when producing the tables on the fly (the response time is just too fast). Or may be they mass-produce those margins of error for all levels of geography they support, but only release some of them in the Summary Files.
As @Kotebiya explained, the estimates should be expected to differ between FactFinder and PUMS analysis. The same comments applies to the margins of error, as well.

American Fact Finder vs ACS from IPUMS


Having knightmares, what to do?

Question: I just hate when my opponent has the knights because most of my blunders happen due to them. I generally like endgames where my opponent doesn't have the knight. I also hate when the Knight enters my territory. So, what to do about this knight phobia? Should I just exchange all the knights in the opening?
Comment: Play chess in the morning.
Comment: Notice that knights can only fork your pieces if they are on the same color. So for example when your queen and king are on the same color, check if they can be forked, and check if your opponent has access to it. It is a bad idea to avoid letting your opponent have knights. It is a good idea to work on your tactical awareness. There is an excellent video by ChessNetwork that deals with how he recognizes certain tactics, for example knight forks, and how he avoids them. It is called "How good is your tactical awareness"
Comment: This question is hard to answer as it stands, since it's not really asking for concrete advice. Sometimes a monster knight is scary for good reason (search for Kasparov's octopus knight for an example where this is the case), and other times it's not really a monster to be scared of. The only advice I could give based on the given info is that you should just grab the bull by the horn and hone your tactical skills; after all, if you're confident that you see all the potential knight forks in advance they become way less scary.
Comment: a knight in your territory is indeed scary. You must eliminate it with bishops or scare them away with pawns.
Answer: The solution is: play better chess. Train your tactical skills so you can better anticipate the opponent's knight's threats (and also make a better use of your own knights). Avoid creating weak squares in dangerous spots of the board where an enemy knight can dominate the position. Pay attention to how stronger opponents play and try to imitate them in the future.
Sure, you can also make inferior trades to eliminate the opponent's knights, but then you are already making a concession and "surrendering" to those knights before they even start putting you in trouble.
Comment: @bretlee Not even the strongest computers can see all the tactics in a position. I'd be happy instead with seeing more than my opponent
Comment: Thanks @David,well i have 1650 rating on chesstempo tactics(blitz),so i know some stuff about tactics ,i thought a point would come where i would be able to see all the available tactics in a position but that never happened.
Answer: Well, you surely could do that, try to use openings that result in knights being cleared off the board. However, that is just a temporary and partial solution. Your opponents might not collaborate and could try to keep their knights, especially if they know or suspect you don't play well against them.
Furthermore, when there is a problem, it is usually best to face it. For this, you need tools, you need to know how to do it (trying to solve a problem without the right tools can be outright frustrating). So, you need to learn how to play against knights. Some suggestions:

As already suggested by others, hone your tactical skills. Train to identify knight forks.
Learn how to tackle knight vs bishop situations. See, for example the question engame with single Bishop or single Knight? The book John Nunn's Chess Course also has a section on this.
Learn how to trap a knight. The book Find the Right Plan with Anatoly Karpov has a section named "A lasso for the knight" with some examples and exercises that may be useful.

Knowing how to deal with a knight helps taking away their scariness.
Finally, best improvement comes with practice. Practice what you have learnt in friendly games and games against the computer. Set up positions where the opponent has a knight and see if you can apply some of those techniques. And, of course, analyze your games to see what you could have done better.
Answer: While I mostly agree with the other answers that the solution to your problem is to grind tactics, there is one piece of advice in particular that changed the way I thought about knights: (I think this is from Silman...?)
Knights thrive on "advanced support points"—supported squares on the opponents side of the board that can't  be contested (this is slightly more general than an "outpost"). When playing against knights, make an effort to deny advanced support points. When playing with knights, try to create them.
Basically, shift your focus from the knights to the squares they can move to.
Answer: Perhaps you dont see Knight tactics because you find it hard to "see" where they go. Ideally, when you look at the board, you see not just where the pieces are, but also where they can go. Do you see Knight moves with less clarity than those of the other pieces?
They have some properties that are helpful in visualising. They always go to a squre of a color different from the one where they stand. If you imagine them to be at the center of a 5x5 block of squares, they go to, and only go to, the squares that other pieces can not.
You might practice solving the Knights Tour, where a Knight on an otherwise bare board has to visit every one of the 64 squares, but only once. Perhaps ypu can use the other pieces to mark where the Knight has been?

Having knightmares, what to do?


Adding Values in Overlapping Buffers

Question: I have a series of points that represent oil and gas wells (over 1,000), and an emissions value for each well. I created 3 concentric buffers that represent increasing distance from the well, and assigned a fraction of the emission value to each buffer. There are many instances where wells are close together, and their buffers overlap. In these overlapping areas, I would like the emission values of the buffers to add. I tried using the raster to polygon tool, but the overlapping emissions did not sum.
Answer: Try using the intersect tool, this will return polygons in your instance, the areas they overlap. You could then do some math for your final values

Adding Values in Overlapping Buffers


Is it possible to stop two male cats from fighting?

Question: I have two male cats with two female cats. The problem is that the older male cat is hurting his 6 month old male kitten.
What should I do to stop the older one from doing this ?
Comment: Is everyone spayed and/or neutered?
Comment: You can try treating this like any other undesired behavior -- I try to tell my too "no" when they're fighting (as opposed to when they are just arguing or playing;  it's a fine line), but I suspect all that will do is move the fight out of your sight. You can try re-introducing them from the most basic starting point,  but this may be something you just need to let them figure out. If they aren't doing damage to each other, that may be a better answer.
Comment: @JamesJenkins They are all normal and we did nothing to them.
Comment: @keshlam What do you mean by re-introducing them, I didn't understand you.
Answer: I suggest that you spay/neuter all 4 of them.
This will not only likely solve the aggression problem but also prevent the problem of producing about 8 kittens twice a year.
That's 16 kittens per year on average in the first year. Then the next year each of the kittens, say half of them are female, will produce 16 kittens itself. That's 16 kittens from the first two mother cats plus 8*16=128 kittens from the second generation cats.
That's 144 cats in year two. And so on.
If you love cats do the world some good and pay for surgery in order to prevent future unnecessary suffering.
Comment: @AsadMarmash I see. So you're a pedigree cat breeder then? What breed are you breeding?
Comment: I can't neuter all of them, every time they make kittens we will sell them when they are grown to a good level.
Comment: The cat that I am talking about is angora, so it might be better if I neuter it because the little cat is somekind of pure persian, so it will help to get better kittens.
Answer: You should neuter the adult male cat. Then you should begin behavior modification as suggested by keshlam in the comment that he should be creating as an answer soon.


What are the advantages camcorders have over zoom digital cameras?

Question: It seems that the latest models of compact digital cameras come with many features which used to be only in camcorders: image stabilization, low-light shooting mode and of course high-definition to name a few.
This article shows some candidates which IMO give pretty good competition to modern camcorders.
I already have a decent SLR camera for taking still pictures, and now i am interested in buying a camera for shooting home videos. I thought of buying a digital camera instead of a  camcorders - but only if I will not be missing out anything that only camcorders have to offer.
Comment: http://photo.stackexchange.com/questions/1497/what-are-the-pros-and-cons-of-a-video-camera-versus-a-dslr-that-can-take-video
Answer: The video capabilities of even the best digital cameras are but a small fraction of these of video cameras. The gap is smaller now but only marginally so.
Where digital cameras compare very well is in terms of image quality, particularly when it comes to low light shooting. For almost everything else, video cameras trump digital cameras.
Camcorders have sophisticated and detailed control over audio recording. They can set levels and recording angle which almost no digital camera can do. You can plug an external audio source on some still cameras but that is about it.
The optical zoom of camcorders is specially designed for video. It moves silently and smoothly to give a natural look. Camcorder lenses are built with a continuous variable apertures so that the brightness of images can vary smoothly rather than in steps (only a handfull of SLD lenses can do that). The focus system works equally smoothly and quietly while most digital cameras record AF noise in the audio track.
Camcorders have tons of features which are meaningful to video. Fading, transitions and even video effects are the norm. They can also record for much longer both continuously and in sequence than still cameras. You can get up to a 128GB SDXC card for a still camera but it is costly while a camcorder can easily have a 200GB HDD built in.
Answer: From the point of view of image quality, I think the choice is clear. Camcorders shoot good video and crappy stills, digital still cameras shoot good video and good stills.
Some digital still cameras shoot even better video than camcorders. I have a $800 Canon Vixia camcorder that shoots 1080p at 24fps with 24Mbps bitrate. The little SX230 HS referenced in your article also shoots 1080p at 24fps but at 36Mbps, and all for about $200, a quarter of the price!
Problems I see with using digital still cameras for shooting video:

Still cameras are not comfortable to hold for shooting video. Camcorders win this category easily.
Audio recording is pretty bad in still cameras, so for any serious shooting you will need a separate audio recorder and microphone, plus editing software.
If you plan to do in-camera editing with effects and such, then a camcorder will probably give you more options than a digital still camera. But if you plan to edit on the computer this is not a problem.


Under what conditions a person can lift a car alone?

Question: I'm thinking about starting my work of physics with this question but do not know how to answer.
Answer: By using pulleys, levers or hydraulics...
A person must do a certain work in order to lift a car and increase its potential energy.  Now, since a maximal force that a person can exert is limited, the idea is to increase a displacement / spatial dimension, i.e.
$$W = \vec{F} \cdot \vec{s}.$$
System of pulleys or lever or hydraulics do exactly that.  You need smaller force, but you exert it on larger displacement / spatial dimension.
Answer: Theoretical physicist would say that it can be done by putting this person and the car in place where gravity is not as strong as on the Earth
Answer: The problem of positioning the force exerted is great. i.e. how does one get directly under the vehicle in a standing/lifting position, and does this 'count' as lifting a car? You could certainly attempt this at an auto-garage with the vehicle raised up on a hoist, and try to lift the already-over-head car for seconds, a few centimeters off the hoist. Still, this would require a very strong (possibly out-of-state) man and a very small car. Otherwise, levers & pulleys it is... since we have already used hydraulics for positioning, like Pygmalion said above.

How 'alone' do you mean?
There is something called 'Hysterical Strength',
from http://en.wikipedia.org/wiki/Hysterical_strength

It is a speculative term that is not recognized in medical academia; the concept has only a small body of anecdotal evidence to support it.

Here is an account of one such incident:
http://www.dailymail.co.uk/news/article-2007972/300lbs-American-footballer-Danous-Estenor-lifts-car-save-life-trapped-truck-driver.html?ITO=1490&amp&amp
In the article above, imagine that instead the vehicle was a much smaller car like a Geo Metro or a little lighter original Mini Cooper (~635kg) (and not a huge cadillac sedan), perhaps the car may have then been feasibly FULLY lifted off the ground if the 300lb football player was that 'hysterical', although not necessary to save the man underneath in that situation.
It would follow that the strongest men in the world are the only one's who could be candidates for such a lift, and even then it's likely they would have to be 'hysterical' (i.e. at full adrenal load + other chemical reactions in the body that heretofore are undocumented due to the rarity of their occurrences) to pick up the small car 'over head', which is considered a great deal more difficult than 'thigh high' lifts.
http://www.dnaindia.com/scitech/report_what-is-the-maximum-weight-a-human-can-lift_1375422
Also the drug Phencyclidine, aka PCP, allows people to perform feats of strength that severely injures them, but cannot feel the resultant pain while on the drug. However I don't think PCP has any place in physics work, as the consequences are too horrendous. I mention it only in the realm of possibility.


Too long to power up

Question: I guess this may be a repost, but I'm using a very good pc(i7-4720HQ, 8gb ram, gtx 950m 4gb) and after I enter my password is taking like 1-2 min for dock and wingpanel to show up. Does anyone know why is this taking so much?
Answer: This is a bug with DBus - see the answer I posted here.
Essentially DBus is preventing everything from starting up, so until that's fixed you need to rename the file causing issues:
<code>sudo mv /etc/xdg/autostart/at-spi-dbus-bus.desktop /etc/xdg/autostart/at-spi-dbus-bus.disabled
</code>
Comment: one more question, does it works if i'm in dual boot with win 8.1?
Comment: Yes, this shouldn't affect that.

Too long to power up


Why is behavior-based robotics not as popular as deep learning or reinforcement learning?

Question: I am a master student in Germany and one of our professors is doing robotics research but with a different paradigm - the behavior-based robotics based on Subsumption Architecture developed by prof. Rodney Brooks from MIT in 1986. I was looking online for more info about this topic but could not find much, compared to the popular nowadays Deep learning techniques. Do you think behavior-based robotics is a fruitful research direction? Does it have any future? At this moment I am inclined to think that Deep Learning and Reinforcement Learning are the ways to add intelligence to robotic systems.
Comment: Current AI trends are just that..**trends**...because lots of people are working on them, it simply advances quicker, and has very very good results...there are *lots* of reasons  that DL and RL are good, but lots that are not good. B.b. R is a field that not so many are working on, that doesn't mean it has no future....it's just a slower one that hasn't had as many break throughs...maybe your prof will have one or two?
Answer: I have not seen that many people working on behavior-based robotics. I am not sure even if Rodney Brooks still works on the subject.
Deep Learning: the approach is good for problems without a model. It is not to-go approach for many robotics problems. Because data collection, labeling, training, testing can be very costly. Even if you are interested in paying the price, sometimes there may not be enough data. If you want to land a rocket to a moving platform, probably you wouldn't want to use deep learning. :)
Reinforcement Learning: the approach does not work in real-life applications. It is costly since you need to do a lot experiments. Most of the times it is not easy to interpret what your agent actually learned.
=== purely subjective statements begin ===
My friendly advice: stay away from esoteric research subjects. I've seen some university professors who have a thing for obscure topics. These professors usually are the ones who passed the critical phase of their careers (pre-tenure) and like to experiment different topics at the expense of their students' career. It is highly likely that the outcome of the experiment will not make the professors more or less famous. They win some small grants and lure some young students to work on esoteric topics as if the subject were very important. You should ask yourself what you are going to achieve after you successfully study "xyz" topic. Is it going to help you find a job in industry or is it going to get you your own research agenda? Do not study a subject just because your professor has funding and he/she finds that topic interesting.
=== purely subjective statements end ===
Comment: I am not an authority in robotics to decide which paradigm is best. My expertise is in decision making (route planning, mission planning, behavior planning, motion and path planning), estimation and control. I'd say if you cannot interpret the output of an algorithm (such as in deep learning, reinforcement learning), that algorithm will never fly on a real robotic platform. Simple A*, PID, Kalman filters will be better approach than most of the complex ML algorithms.
Comment: What paradigms do you think is best to study for specific robotic AI?
Answer: Deep Learning and behavior based robotics as well were developed as the opposite to something which was common before. In the 1980s, Brooks developed the subsumption architecture as an alternative to the former AI planning technique which was widespread discussed in the 1970s together with LISP symbolic systems. Behavior based robotics says in short, that there is no need for an abstract representation of the world which is formalized in the STRIPS language, instead the robot has to react to incoming sensor perception.
Deep Learning were also developed as a valid alternative to something known before. The main idea behind machine learning is, that there is no need to create sourcecode like in a programming project. It's enough to train neural networks with example data and the programming part of a robotics project is low or not there. A certain paradigm becomes successful, if a larger audience has the same understanding of how technology should be realized. The reason why deep learning is more attractive to a mainstream audience than behavior based robotics, is because the number of people who are trying to escape from symbolic AI is low, but the amount of people who doesn't understand why they should program is large.
Deep learning can be summarized to the idea, not to write a single line of code, but letting the combination of a GPU plus backpropagation algorithm do all the work. This sounds attractive to newbies in the domain of AI because writing millions lines of code is a complicated issue.
Comment: So the classical way to program is still far more suited for robotics AI than DL/RL?
Comment: It's hard to judge about neural networks with a neutral point of view, because the development is in an early stage. Most of the papers were published in the last 5 years and the idea of utilizing machine learning for solving AI problems makes sense. What we can say for sure is, that deep learning was equal to a revolution.


What happened in the Doctor's past that made him destroy Gallifrey prior to the Day of the Doctor?

Question: In the Day of the Doctor, both 10 and 11 remember destroying Gallifrey. Does this mean that in their past, the Interface never showed up? or did he just not listen to her and destroyed the planet right away?
Answer: Hurt's Doctor is a past version of 10 and 11, so all events that happened to Hurt's Doctor happened to 10 and 11 also.
If you recall, at the end of TDOTD, Hurt's Doctor says how he won't remember any of the events that took place, and instead he would only remember destroying Gallifrey in lieu of saving it. But they don't actually destroy Galiffrey do they? So how can 10 and 11 remember destroying Gallifrey? My guess is that whenever 10 and 11 go on about how they destroyed Gallifrey, they weren't being literal in the sense that they actually recall seeing the planet explode.
The War Doctor already had the intention of destroying Gallifrey before the events of the Day of the Doctor, so when he forgot everything that took place from when he stole the Moment up until his regeneration into Eccleston, I guess that afterwards he could logically reason that he must have destroyed Gallifrey and his memory must have been wiped during the ordeal somehow. And  as Gallifrey wasn't there anymore when the War Doctor regenerated, the only explanation to that would be that he destroyed it.
Also, we know 10 and 11 couldn't have destroyed Gallifrey, because the Silence wanted to kill him to prevent him from bringing back the Time Lords into the universe (and this was before the Day of the Doctor, before the 11th Doctor had the chance to see his old self again). No Time Lords== No Silence and most of the 11th Doctor events wouldn't have happened.
Comment: @DoctorWho22  Your idea couldn't have happened because lije you said in your answer,  the11th Doctor clearly stated at the end of the episode that the time streams were out of sync, hence why Hurt and Tennant wouldn't remember any of the events. They couldn't have used the memory erasers because why would  Tennant have had to bother asking Smith if he'd retain the events in his mind, and also Hurt and Tennant were already leaving in their Tardises, so how could the period of memory erasing fit in? And anyway with the whole time being out of sync thing why bother?
Comment: @DoctorWho22 the younger doctor never remembers meeting their future self, in any episode where a crossover occurs. That's just how it works.
Comment: One problem with this is that Smith never remembered meeting Tennant and Hurt, so Tennant AND Hurt would have to have forgotten the events, which is why I think they used the Black Archive's memory wiping devices to erase their memories
Comment: I'd have to watch the episode again... Because if that's the case Time Crash wouldn't have worked out the way it did...
Comment: @OrangeDog There was a small crossover thing called Time Crash where the Doctor remembers what he does in the future when they meet because he witnessed himself doing it.
Answer: Actually the answer is quite simple... from what I recall the Black Archive had the memory wiping devices... At the end of the episode of The Day of The Doctor I believe there was some hints to using them to forget the events that happened that day.  I believe Hurt said something along the lines of how he will forget what happened and that he will have to live with the fact that he destroyed Gallifrey, because he will be under the assumption that it was destroyed.
Also we never knew about The Silence's true role about bringing back the Time Lords until the Time of The Doctor when Tasha Lem revealed that the splinter faction of the Papal Mainframe went back along The Doctor's Timeline to prevent him from answering the question.
So there's two possibilities in my eyes, either
A.  The events that occurred were always meant to happen and Hurt's Doctor and Tennant forgot the events from the memory wiping devices or because of "timey wimey" (you know how the doctor's aren't supposed to cross their own timeline)
B.  Changing the past / future has major consequences which is why they had to wipe both Hurt and Tennant's memories of the events so that everything would work out as it did in The Day of the Doctor.
Answer: He was aware that the Time Lords became just as cold and unfeeling as the Daleks during the Time War. In the Time War, both the Daleks and Time Lords wiped out entire planets and civilizations, made them as if they never existed, as both sides constantly used time travel to rewrite history. The doctor could not take such widespread death and destruction, so when he had a chance to "bottle up" both sides in a far flung dimension or time stream, he took it. He feels great guilt for betraying his kind, and causing the seeming deaths of Daleks and time lords, but he did it to save the lesser civilizations caught up in the Time War.
Answer: When the newest Doctors decided not to destroy Gallifrey they created an alternate timeline and essentially another dimension where in one Gallifrey was destroyed by the Doctor and the other it was saved. Since the past Doctors and their memories were not part of the second timeline they will no memory of Gallifrey being saved.
Comment: Is this based on canon?