Backup server external backup

Question: I have a 4TB External HDD and i converted this HDD file system as ext3
i want to know how can i take backup of backup server using this HDD
i have already a 3TB HDD(with power), in that i could able to take backup
which is an ntfs file system.
in this new HDD i have seen its a GPT file system and now i partitioned this and change it as ext3
if anybody needs further information i can give..
Please help to find out a way...
Answer: If you want a fairly simple backup then you can use rsync. If you want a more sophisticated backup then rsnapshot will likely work.

Backup server external backup


Is it possible to create a searchbox for my site using javascript?

Question: I'd like to create a search box on the home page of my site that would be able to search the entire site. I know it's a very general question but I'd be very happy with just a general conceptual answer is there anyway to do this?
Comment: Do you intend to use any other technologies outside HTML and javascript?
Answer: You can't really do this using Javascript. You'll have to use some sort of server-side language that has access to your database. Alternately, you can use something like Google Custom Search Engine to provide searching capabilities.
Comment: +1 for Google. Best way to do it without messing about with server side.
Answer: Once you start wanting users to be able to search your site, it implies that your site is larger than just a few simple HTML pages.  Have you thought about using something like Drupal, Joomla!, Wikimedia, or some other CMS?  Most of those have search capability built in (one way or another).
Answer: People are going to tell you no. They're mostly right that his probably isn't the best way to do this.
But depending on your site, it may be technically incorrect to say this can't be done with JavaScript. If all the documents you want to be searchable have a unique URL that's used throughout the site, and if their graph is connected, I think you could write a spider in JavaScript that begins indexing all these pages as soon as a user hits your site. It'd do what any other spider did: look for links on the current page, request the documents behind them (using XMLHTTPRequest or a frame or popup window of some kind), process the document and index keywords based on some scheme, and store the results (possibly in a a cookie).
Of course, duplicating all this work for each visitor doesn't make a lot of sense, which is why the other people telling you no are mostly right. But it's theoretically possible.
Comment: I'll add an offsetting upvote.  While that's clearly not a good solution to the indexing problem, it IS a good example of WHY client-side isn't the way to go about it.
Answer: This is would involve much more than just Javascript and depends on a number of different variables. Often, sites are built on a MySQL (or similar) database. If this is true in your case you may want to use some PHP to get into it and search through each record. Here's an example using PHP and MySQL.
For the form, something like this will work:
HTML
<form action="?" method="get">
    <input type="text" id="search" name="search" />
    <input type="submit" name="submit" id="submit" value="Search" />
</form>

Then you'll need to use some PHP, assuming you want to search the title and body of one table of blog posts:
$search_terms = mysql_real_escape_string($_GET['search']);

$resc = mysql_query("SELECT * FROM blog_posts WHERE title LIKE '%".$search_terms."%' OR body LIKE '%".$search_terms."%'");

$posts = mysql_fetch_assoc($resc);

now $posts is an array containing all of your posts which match the search terms in their title or body.
NOTE: In order to search for text type MySQL fields you will need to make the field a FULLTEXT index.
Check this link out for more info: http://devzone.zend.com/article/1304
This is a VERY SIMPLE solution, but it will get you on the right track.


When shifting gears, how does a bike chain catch the new cog so reliably?

Question: I think I understand the derailleur mechanism pretty well, yet I still find it surprising how the chain catches on the new cog so reliably.  Is there something I'm missing?  Is it just with the proper derailleur alignment, the chain will inevitably catch?
Comment: About a century of practice.  A big jump in the technology occurred with the invention of "indexed" shifting, as that involves having "ramps" on the sides of cogs to lift the chain from a small cog to the next larger one.  And, properly adjusted, "indexed" shifting eliminates the "searching" that was necessary after an unskilled shift, in order to get things perfectly centered.  (A skilled cyclist could hit the center of the adjacent gear on a non-indexed bike nearly as well as on an indexed one.0
Answer: A great deal of engineering has gone into making shifting smooth and predictable. Up until ~1984, shifting was done by feel and sound: the shift lever moved continuously through its range, and you moved it until it caught the adjacent gear. Different brands had different actions, and you had to develop some technique.
In 1984, Shimano rolled out "indexed shifting" (there had been previous attempts, but this time it really took). Here, the shift lever clicked into specific positions; the spacing between gears on the freewheel was standardized (before, the spacing varied within a freewheel); the shift cable was pre-stretched so the action wouldn't change; and so on. There was a lot of skepticism that indexed shifting would stay reliable in the long run, but it did, and took over.
Since then, there have been additional refinements. Individual gears on a cassette have "ramps" that help lift the chain from smaller gears. Gears are aligned relative to each other to ensure good uptake. Chainrings have pins to help lift as well.
Comment: Also, once the *tensioned* chain is over a sprocket, it pretty much has nowhere to go but to drop onto the sprocket teeth. The miracle of modern derailleurs is that it does so smoothly and without skipping.
Comment: The ramps on the cogs were a part of the indexed shifting scheme, pretty much from the start.  Without them it wouldn't work.  A big part of the problem is the need, with the older schemes, to "over-shift" when shifting to a larger cog.  The ramps largely eliminate this requirement.
Comment: I actually had the first iteration of Dura Ace SIS. It didn't have ramps, although IIRC it did have twisted gear teeth to try to help catch the chain. As far as I can tell, ramps were a part of gears around 1990.


How to connect USB CDC devices?

Question: I have a Zebra MC3300XR SERIES RFID reader that support USB CDC, how can i read the scanned RFID programmatically in the raspberry pi? is it possible?!
Answer: Good news, the Raspbian has CDC ACM drivers already built in as plug-and-play, so /dev/ttyACM0 should show up when you plug your adapter in if it actually  CDC ACM.
"/dev/ttyACM0" is USB0, On my system they generally show up as "/dev/ttyUSBx" I have seen on some of my Linux machines but not recently. That also varies with the IDE I am using.
Comment: Maybe expand on what you mean by "/dev/ttyACM0 should show up when you plug your adapter in"?

How to connect USB CDC devices?


What type of shop could make an isetta body?

Question: I am curious how car bodies were made back in the 1950s. Specifically the micro-car bodies like the Isetta. What techniques and tools were used back then? They seem fairly simple. Could a body for an Isetta be built in a small shop?
Answer: I don't think there was anything special about the manufacturing. Pressed steel sheets for the panels which were welding together.
The biggest cost specific to the Isetta would have been the dies used to press the panels. The presses could have been used for any similar-sized panels. The original Italian manufacturers also produced motor scooters and refrigerators, not "full size" cars.
Some pictures of the UK Isetta assembly line here: http://www.isetta.org.uk/page16.html
The UK assembly line was constructed from scratch in just 3 weeks, in a factory space which had previously been used to repair railway engines. That suggests there was nothing particularly novel about the processes used.
Comment: [Stamping](https://en.wikipedia.org/wiki/Stamping_(metalworking))
Comment: From the raw pressings received from Bavaria, and welded on jigs proof-tested at the German factory, the bodies were built on one line. - your link
Answer: For the Isetta you can see that the overall body shape is quite flat and boxy, without the more pronounced compound curves of other cars of the period. This makes it relatively easy to produce the panels.
As well as die formed pressings there are various manual methods for forming sheet metal body work using tools like power hammers, swage tools  and english wheels. These are still used today for small volume and custom car bodies although they are highly skilled processes they are certainly within the scope of a small shop.
This is also the start of the period where you begin to see to see proper sports cars with specifically designed light weight space frame chassis and aluminium and, later, fibreglass body-shells, often using fairly standard engines and transmissions as opposed to the pre-war tradition of very basic ladder chassis with bigger and bigger engines.
Traditionally there was a distinct separation between the engineering aspects of the, engine, chassis and drive train of a car and the coachwork and interior of a car but the pre and post war period started to see this becoming more integrated.
There were a lot of small volume cars made in the 1950's as the post war economy in Europe meant that there was quite a lot of surplus material and industrial capacity but not much cash for investment in new tooling so it is common to see cars with relatively advanced design but with quite simple manufacturing processes, often making use of post-war surplus materials and parts.


Why do led/incandescent combo dimmers specify lower led wattage?

Question: When looking at combo dimmers most of them are rated for 600 when using incandescent, but only 150 when using leds. Surely the switch should be able to shed the same amount of heat regardless of what bulb is used -- why the difference?
Comment: Pretty well answered here, I think: https://diy.stackexchange.com/a/201548/18078
Comment: @Ecnerwal: that suggests incandescent lamps are actually de-rated because of start-up current spikes, not the other way around. I believe the OP needs to look at power factor; some LEDs have miserable PF; as low as 25% for some naïve/cheap capacitive dropper based bulbs, compared to 100% for incandescent ones. That needs to be accounted for, even if not billed for (yet, wait for smart metering to remedy this and prompt the need for new labels on bulbs).
Comment: It depends on the type of power fed to the LEDs to determine what kind of heat x watts will burden the switch with. Rather than break it down by tech (which is complex and confusing to consumers to say the least) they go for a worst-case scenario. It doesn't hurt marketing because 150W of LEDs is generally PLENTY for most rooms; way brighter than 600W of Edison bulbs.
Answer: The main difference would be the harmonics and distortion that occur in the driver that powers the LED lights.


fingering for violin

Question: When reading music how am I supposed to know which fingering to use? Let me clarify. I can read the notes. However, when there is an A how do I know if I play an open A or the fourth finger on the D string?
Comment: If it's not specified, then you should find some balance between what is most comfortable to play and what sounds best.  This mostly takes experience, but I am sure there are violin-specific aspects that someone could flesh out better than I could.
Comment: In my experience, four fingers is to be preferred in most cases, but in some other cases, an open string is almost necessary. The main idea is to eliminate string crossings in any way possible.
Answer: You learn by starting with exercises and pieces where the fingering is marked on the score, and progress from there by experience.
If the answer isn't "obvious" in a particular situation, you try out the different options and find which is the best compromise between "easy to play" and "sounds good" - an open A string sounds different from the same pitched note on the stopped D or G strings.
Of course if you are playing music that was actually written for violin by a composer who knew what he/she was doing, that often makes the choice more obvious!
Note: you only mentioned "fourth finger on the D string" and "open A string", so maybe you haven't progressed beyond the first position yet. When you do, the will be several more fingering options available, and some of them might be easier than the two you mentioned.
Comment: I would just like to add that for intonation sake beginners should rely on  open strings as much as they can. I let my students in the beginning use open strings as much as possible. but as their intonation get's stronger I gradually start emphasizing the 4th finger.
Comment: You are correct. I have not gotten to changing positions yet. I have so far been using the fingering that is the easiest transition.
Answer: This depends a lot of the time on the style of the piece, any fingering markings in the piece, and your own level of experience and ability.
A calmer, more elegant piece of music should use the 4th finger to play open strings. This makes your playing not suddenly sound so sharp or harsh (like when suddenly playing open A or E string). However, other styles of music or more forceful music can use an open string for that extra emphasis.
If a composer really wants you to use 4th finger, then they will put the little number "4" above the note to tell you to play with a 4th finger.
It's important to practice and develop your pinky finger to be stronger to play nice, lush 4th finger notes. Play your 4th finger, and play the open string that corresponds at the same time to develop good intonation. If you really need to, then shift positions (like to third position) and play the 4th finger with a different finger, like second finger.
Comment: (+1) when you say 'sharp' here you mean a 'harsh' sound, or something similar? rather than pitch
Comment: I mean more of a harsh sound, or perhaps "not as humble" as a 4th finger note.
Answer: One of the skills of more advanced violin playing is just that....choosing which fingering works best. For many notes, there are many places they can be played. As you reach a more advanced level and learn more positions, you'll develop the ability to decide which pattern works best for what you're playing. Hopefully you have a teacher who is taking you through a standard progression of learning so that you will get to this in due time.
Answer: There are many aspects to choosing the best fingering such as (using your example of 4th finger vs open A):

The dynamics of the section. A 4th finger is often best in a quieter dynamic.
The tempo. In a slow tempo the 4th is usually best because it allows for vibrato.
The notes before and after. Always try to avoid unnecessary string crossings.
Period and style of the music.
Proficiency of the player. Open strings are 'safer' for beginners because many beginners find it difficult to consistently play the 4th finger in tune.
Personal preference. After other considerations, fingering is up to you. Feel free to experiment and use whatever feels most comfortable.
Answer: The problem is that the answer depends on the experience and skills of the player.  An open string is usually the wrong choice for a single long note since you cannot add vibrato or intonation corrections to it (for the open G string there is no alternative, but experienced players will finger a vibrato on the non-bowed G one octave higher on the D string, and sympathetic vibration will add some contour to the tone played on the open G string).
In particular, when playing with a straight-tone instrument like a recorder that has rather limited means of pitch adjustment compared to a violin (particularly when played by players in progress), playing an open string is close to impossible without the result sounding out of tune (of course, better results by intonation-adjusted fingering and/or vibrato require a reasonably skilled player on the violin then).
When a beginner is comtemplating playing an open string or fourth finger, more experienced players will often revert to using a different finger such that a containing phrase will get by without a string change.  Even if it is the rest tone after an ascending phrase, jumping into third position may be preferable since the quality of vibrato on the middle finger might be better than on the pinky.
Bach's violin solo sonatas and partitas don't contain fingerings in the manuscript/Urtext, but some passages and partly entire movements work so obviously better with a particular choice of fingering that it is actually a immensively gratifying experience puzzling it out.
That is not a general rule: for many composers, the violin is sort of an "anonymous" melody instrument with a particular timbre, and they don't write as much for the violin as generally check their writing (or have it checked) for playability after the fact.  For symphonic composers, having intimate knowledge of all involved instruments and their technical constraints may be a bit much to demand.
I've actually seen several different fingerings suggested in one part score, the fingering below the notes being "easier" (mainly confining itself to the more common first and third position) with the upper fingering being more musically sound by using positions as needed for avoiding unsavory string changes in mid-phrase.
Answer: You should improvise and try out different fingerings and figure out which works best for you. And as you get more comfortable with more positions, you'll have more fingerings to choose from.
As for whether you should play an open A or an A on the D string, in actual performances, you should play it on the D string (or G string if the music demands it). Open A (and especially open E) don't sound very good if the note is very drawn out, and not playing an open A also allows you to do vibrato. At least that's what I've learned in my lessons

fingering for violin


How to install downgrade of SQL Standard 2016 to Standard 2014

Question: This is probably a super basic question, but if I purchase an OEM SQL Server 2016 Standard edition, how would I install it as 2014 to match the other servers? Can I get a 2014 installer and use the 2016 license key during the installation?
Comment: Do you mean retail license instead of OEM?  Volume licenses purchased and Software Assurance do qualify for downgrade rights in most cases.
Comment: Yes, retail license, it would not be through volume or SA.
Answer: If you want a Sql Server 2014 instance, you'll need to install that specific version. Installing Sql Server 2016 will create a Sql Server 2016 instance, but you can control certain database behaviors to be compatible with the specified version of SQL Server by ALTERING the COMPATIBILITY_LEVEL.
Comment: Note that once a database has been attached to the 2016 instance it can no longer be attached to an older instance. Compatibility level affect the behaviour, not the persistence. Test to ensure you can perform all the tasks you require with this mixed configuration.


Calculate a rotation around an arbitrary axis

Question: Suppose I have two 3D triangles before & after a single rotation around an unknown axis.
How would I go about finding this axis?
Answer: Take a point $P$ and it's rotated point $P'$.
Find the plan that runs through the middle between them $C = \frac{P+P'}{2}$ and is perpendicular to the line connecting them.
Do this for all 3 of them and find the line of the planes' intersection. That will be the rotation axis.
If all mid-planes are coplanar then you can use the planes of the triangles themselves.
To get the angle you can take a $P$ and $P'$ again and project them onto the axis.
Take a point $A$ on the axis and the direction $v$ of the axis. The projected point is $P_p=A+\frac{v \cdot (P-A)}{v\cdot v} v$. And then the angle is $acos(\frac{dot(P-P_p, P'-P_p)}{|P-P_p|* |P'-P_p|})$
Comment: 2 is enough but the third lets you verify that it's indeed a rotation. As for angle you can project the point and it's rotated point onto the axis get the direction to the points and dot product.
Comment: @ginsunuva there is a solution for that, see edit. The only remaining issue is a degenerate triangle which is parallel with the rotation axis but that has multiple solutions.
Comment: Do I really need 3 correspondences, or is 2 enough?

Additionally, how can I get the angle of rotation from this?
Comment: I guess two can have degenerate cases if they're coplanar with the axis of rotation, so three can help, but three can also be bad if they're still coplanar with the axis.  Like for a triangle on a door that rotates open, all the "midpoint-planes" are the same.
Comment: Great, also how do I actually do the project/find angle thing? How can I get two points to be in this new 2d coordinate system defined by the orthogonal plane to the rot-axis, so I can do a dot product?


After lowering maxmemory, redis still has high RSS memory

Question: I would like Redis to return some memory. I lowered the maxmemory by 10GB but noticed Redis is still "holding onto it" in RSS based on "used_memory_rss". Based on http://redis.io/topics/memory-optimization, it looks like Redis won't return the memory to the OS. How do I force this? Is there any way to do this without restarting Redis?
Comment: If you want a database server to be efficient, you shouldn't expect it to give acquired memory back. Usually the database size is much than the onboard memory, so the server needs all the memory it can get. I've never worked with this specific platform; nevertheless, I find Redis's "holding onto it" a perfectly normal phenomenon.
Answer: I had the same problem and this answer was helpful.

even though Redis isn't using the memory anymore, the allocator just hasn't released the memory back to the OS yet. Reds v4 has a MEMORY PURGE command to tell the allocator to release the memory it isn't using, but unfortunately that isn't available to you on v3.2.
Answer: It is possible to reconfigure redis on the fly but it won't re-read the config file until the next restart. To do this you have to use the CONFIG command to change the value.
Snippet from http://redis.io/topics/config

Changing Redis configuration while the server is running
  It is possible to reconfigure Redis on the fly without stopping and restarting the service, or querying the current configuration programmatically using the special commands CONFIG SET and CONFIG GET
  Not all the configuration directives are supported in this way, but most are supported as expected. Please refer to the CONFIG SET and CONFIG GET pages for more information.
  Note that modifying the configuration on the fly has no effects on the redis.conf file so at the next restart of Redis the old configuration will be used instead.
  Make sure to also modify the redis.conf file accordingly to the configuration you set using CONFIG SET. You can do it manually, or starting with Redis 2.8, you can just use CONFIG REWRITE, which will automatically scan your redis.conf file and update the fields which don't match the current configuration value. Fields non existing but set to the default value are not added. Comments inside your configuration file are retained.

CONFIG SET details
If that doesn't work and you have a slave you could play a shell game with them and reduce the memory on the slave, restart it, promote that to the master and reduce the memory on the original master and restart it.


Unable to open JPGs with Fireworks CS5 in Windows XP by right-clicking and choosing "Open With..."

Question: I upgraded from Fireworks CS4 to CS5, and now when I right click on a JPG image and go to "Open With" I do not have Fireworks CS5 as an option. So, I go down to Choose Program and then Fireworks CS5 is no where in the list of programs. So I click Browse and navigate to my Fireworks.exe file and choose it, but it still doesn't appear in my list of available programs. If I navigate to the Fireworks.exe file normally and double-click it, it opens just fine, so I know that there is nothing wrong with my Fireworks program. Also of note: when I right-click on PNG files on my computer, I DO have the option to open in Fireworks CS5 and doing so works perfectly, it's just JPGs.
Answer: I think this is an OS issue. I remember having the same issue even on the Windows XP and 98 days. It's got something to do with file and default application mapping. I'd suggest you rename Fireworks.exe for CS5 to FW5.exe and follow the same steps you described. Since the executable is different, it might work. Otherwise, same exe file is mapped for CS4 and OS is not mapping CS5 even though you are explicitly telling so.


Convert DOC to PDF

Question: I know this question has been asked over and over, but I can't find the answer I'm looking for. So I'll shamelessly try again.
I'm looking for a reliable, stand-alone tool for converting Word documents to PDF. A command-line tool or .NET library would be ideal, but a regular Windows DLL could work, too. But my app can't rely on any of the following:

installing a printer driver
scripting MS Office
scripting OpenOffice
licence for a commercial library
controlling a windowed application via the UI

On the other hand I'm not looking for perfect fidelity, in fact I don't even care about fonts and formatting, just about getting the basic table/textbox layout about right.
I looked at Aspose.Words.NET, and while it does the conversion job perfectly, it's expensive and seems like overkill. I was tempted (in my frustration) to just use the trial version of Aspose as this project isn't for public release, but the trial version won't work with documents above an undisclosed number of paragraphs and the documentation is very vague on this point so I wouldn't know what to expect down the line. Anyway that would be wrong. ;)
Any ideas?
Answer: have a look at this thread: How do I convert Word files to PDF programmatically?.
ITextSharp is a popular choice for document conversion (it's free and open source)
Comment: IText and ITextSharp are not free if used for commercial gain.

http://itextpdf.com/terms-of-use/

Convert DOC to PDF


Taxes on gifting a home to a son?

Question: My father owns a property (approx. value $175000) he owes $60000.  He wants to gift the property to me.  1. Can I pay (or give him the money to pay) the remainder of the mortgage and have him gift the house in its entirety?  What are potential Gift tax issues?
Comment: Let's see now; you want to gift your father $60K to pay off the mortgage and then he will gift to you a house worth $175K? In the US, _both_ gifts would be liable to incur gift taxes.
Answer: Why not just buy it from him for $60K? The discount you'll be getting from FMV should go on your fathers' gift tax return (the $115K), and your father won't be able to claim a loss (since its a related party transaction), but your $60K will not be considered a gift.
Comment: I think that may be the option.  Will he actually get taxed on the 115K?  WI does not have a gift tax, so I assume he will get taxed for income.  I am confused about the federal gift tax.  13k is exempt, but is will fall under the 5M life time. Can he and my mother gift 13k to each of our family members?  There is 5 of us That would be 13k x 2 x 5 = 130k.  If that is the case does everyone have to be on the deed?
Comment: @Brian you cannot split a gift - unless it gets titled to all 5 of you together. Think if that's what you want. Talk to a tax adviser (EA/CPA licensed in WI) for best advice on your options here. Getting free advice on the Internet is very likely to cost you more than what you'd pay to a professional.

Taxes on gifting a home to a son?


Does Pagination with Infinite load affect SEO

Question: I have a website developed in React for the frontend. I can see links on the pages with NO infinite load have got indexed on Google. However, links on the ones which have infinite loading for pagination haven't got indexed yet. It's been 3 weeks. Do I have to convert the pages to normal pagination without infinite loading?
Answer: Since your front-end is in react.js and google has limitations for parsing(crawling) content within javascript, it would be a bit troublesome for you.
Don't worry. Where there is a problem, there are solutions.
Although there are multiple ways to solve this problem, there is one in particular recommended by google:
"To make sure that search engines can crawl individual items linked from an infinite scroll page, make sure that you or your content management system produces a paginated series (component pages) to go along with your infinite scroll."
Comment: For details, refer: https://webmasters.googleblog.com/2014/02/infinite-scroll-search-friendly.html
Comment: https://www.quicksprout.com/how-to-create-an-seo-friendly-infinite-scrolling-page/
Comment: Try it out and let me know if the problem still persists after a few weeks. Google might take some time to crawl the page and index them, after you have made changes.
Answer: Googlebot doesn't scroll.  Googlebot doesn't click on anything.  The only thing that Googlebot does to discover content is scan the document and look for links.  It can find them in <a href as well as strings that look like they could be links in JavaScript.  If the only way to get to the content is to scroll to it, Google will never find it.
You can usually overcome this by creating links to page 2+ while still allowing users to scroll to get there.


How can I setup a server so FTP is available through the Internet, but HTTP only through a VPN?

Question: How should I setup a server (Windows Server 2008 R2) such that FTP access is possible over a normal Internet connection, but HTTP access is only possible when connected to the company VPN?
Answer: This is simple, but there are a few ways to go around it. The way I would do it:
If this server is behind a router (but with NAT) and it has the VPN endpoint the other side of the router/same network as the server, you simply need to forward the FTP ports you use from the router to the server, but just don't forward port 80 / the HTTP port you use.
If you want to be a bit more secure and have it only accessible via VPN and not internal network, then use IP restrictions on the HTTP server to only allow access from your VPN DHCP pool / Static reserved addresses.


How to open applications regardless of required version?

Question: So I downloaded this application that I am relatively sure is able to run fine on 10.7.5 (My version of OSX), but when I try to open it, a message pops up saying that it requires at least version 10.8.5. The reason I think it should work with my OS is because an older version of the app does, and as far as I can tell, there is no real content added between that update and this one, so I don't feel they could have refactored it so much in a somewhat insignificant update that it no longer works on my OS. (And this application really doesn't let you downgrade, so done say I should do that) It doesn't open and then crash. When I try to open it, just a window with the Finder icon pops up saying that it doesn't work on the current version of my OS, and I need 10.8.5. The application doesn't even try to open. So I feel that there must be a flag somewhere in the code or something dictating minimum version required. So my question is: Is there a way to ignore this flag and open this application regardless of minimum required version?
Comment: Why don't you download the older version of the app then?
Comment: Any reason why you can't upgrade to OS X 10.8.5?
Comment: Ok. I said that you can't get the older version of the app. They force you to update it, and they don't really let you downgrade. And also OS X costs $20, and I paid the shown price for the app, so I shouldn't have to pay more.
Comment: @RothX Yosemite (OS X 10.10) is free.
Answer: That check is done by checking the application's plist.

Right click on the application and click "Show Package Contents"
Open "Contents"
Open "Info.plist"
Scroll down to where it says "LSMinimumSystemVersion" or "Minimum system version" depending on the editor you're using.
Replace the string on the next line which should be "10.8.5" (or to the right of the key, again, depending on the editor) with "10.7.5". Try to open the app again.

You may have to restart after this change.
Comment: It's possible they're using 10.8-only code, even if they're not using any user features from 10.8. That could be the reason.
Comment: So I tried this. It still didn't work, it came up with the same message. I searched for apps ignoring plist minimum version, and it said I had to use the touch command in Terminal. I did this and it sort of worked. WHen I tried to open the app, it didn't open, it just said that it quit unexpectedly. I'm guessing this means that they hardcoded the minimum version in. Oh well. Thanks for your help anyway.
Comment: @WilliamTFroggard The next step would be to implement whatever symbol the crash log says the app is looking for. :) https://apple.stackexchange.com/questions/414688/how-can-i-run-newer-unity-games-on-os-x-10-9-mavericks
Answer: I'm on macOS 10.14 trying to run a program meant for 10.15, but the "Info.plist" file didn't contain any reference to a minimum system version. However, I was able to launch the application by navigating to the <code>/Contents/MacOS</code> directory inside the package contents, right clicking the executable found there, and selecting "Open".
Comment: Did you `touch` info.plist?
Comment: No, but there was no system version listed there to change.


merge changes with GIT and SVN

Question: Here is my problem. I am working with an external consultant, who created some code that he keeps in a GIT repo on github. Internally I have a development server that has SVN, and I can make a copy of his code in my internal SVN repo. I don't want to give my consultant direct access to my internal server, but I want to be able to have any changes he makes (and saves on github) to merge with what is in my SVN repo. This does not have to be automatic whenever he updates github - I just want to have a fairly simple process that I can run to merge his changes into my internal SVN repo. Note that I will also be making changes myself to the code in the SVN repo, so I can't just mirror his github git repo to SVN every time he makes changes. So how can I make sure the SVN repo can keep track of changes that both of us make?
Comment: Not a solution to a particular problem - but an advise - upgrade to git: distributed VCS is superior.
Answer: Clone your repo with git-svn and add his repo as a remote. Now you can merge his changes into your svn whenever you want to.
Answer: Read this topic (with comments and warnings).
In short - you can use SVN-client for accessing Git-repo, hosted on Github, but "dumb" merging of externals and local may be troublesome (test your case)

merge changes with GIT and SVN


String buzzing even after straightening neck from shop

Question: I had my guitar's neck straightened from a shop, the action now is very comfortable as compared to before but I'm still getting buzzing before the 12th frets on all strings but its too much in the G string. Should I take it back to the shop or can it be easily fixed at home? I have fender MZ5 Mexican strat. Also should my guitars neck be completely straight? The guy at the shop told me its fine but I read some articles that it should be a little concave forward.
Comment: Another service for you to consider -- whether on your own, or via the shop -- is to level your frets. This is an essential step to minimizing the action height. Level frets plus a slightly concave relief will yield the best action. Then it is a matter of cutting the nut and setting the bridge (saddle) heights to personal taste. Finally, adjust the intonation again and you should be ready to go.
Comment: I've had similar trouble, and it turned out that the real issue was that my frets were worn down.  I ended up getting a re-fret job and problem solved.  I'm not saying this is your issue, but something to be aware of.
Answer: Straightening a guitar's neck is easy to do at home - if you know what you're doing. You took it to a shop, because you felt they knew the job better. Take it back, explain the problem. It may be they've adjusted it too far, it may be the guitar won't take all the adjustment, it may be it just needs the action tweaking.Whichever, the job's been paid for and it's not a good 'un. If you can be there while it's being worked on, do that. At least you'll have some idea as to how the mechanics works for another time. Necks are rarely dead straight, there's usually a bit of relief - the strings need a bit of space in which to vibrate. Sounds like there's not quite enough on your guitar.
Comment: That's what I was thinking. I'll just strictly tell them not not keep it so straight.
Comment: There's always a trade-off between the straightness of the neck and the action that results from it. String tension is another factor, and if they get changed, it may precipitate sorting out the intonation. Pandora's box comes to mind !
Comment: Yeah I took it back to the shop and he gave the neck a little relief and now all the buzzing is gone. Maybe for the next time I can do it myself.


Eigendecomposition of analytic Hermitian matrix-valued functions of several variables

Question: If $A(t)$ is an analytic, Hermitian matrix-valued function of a real variable $t$, then it is known that there are analytic functions $\lambda_i(t)$ and $x_i(t)$ corresponding to the eigenvalues and eigenvectors of $A(t)$.  My question is: what if $A$ is an analytic function of two or more real variables?  Does anyone know any relevant references?  More specifically, in my case $A = A(s,t)$ is analytic in a neighborhood of $[0,1] \times [0,1]$.
Comment: Eigenvalues are roots of characteristic polynomial, with coefficients that analytically depend on $(s,t).$
Answer: See assertions (L) and (M) of the main theorem of

Andreas Kriegl, Peter W. Michor, Armin Rainer: Denjoy-Carleman differentiable perturbation of polynomials and unbounded operators. Integral Equations and Operator Theory 71,3 (2011). (pdf)

Essentially it says, that you can have either:

real analytic eigenvalues and eigenvectors after finitely many blow ups and power substitutions of the parameters
eigenvalues or eigenvectors which are special functions of bounded variation, if you do not want to mess with the parameterizations.

For the $C^p$ case, see

Differentiable roots, eigenvalues, and eigenvectors, Israel J. Math., doi:10.1007/s11856-014-0007-5. (pdf)
Comment: Thanks for the reference.  These results are for unbounded operator valued functions. Are stronger results available for finite-dimensional matrix valued functions?
Comment: Finite dimensional results are essentially the same.
Comment: This example was very illuminating:

$$A(s,t) = \begin{pmatrix} s^2 & st \\ st & t^2 \end{pmatrix}.$$
Clearly A(s,t) is analytic, but the eigenvectors cannot be chosen to be analytic in a neighborhood of the origin.  This is from the paper by Kurdyka and Paunescu in the references of the first paper you linked.  Much appreciated.


How can I automatically disable WiFi when I connect to an Ethernet network?

Question: I would like my WiFi to automatically disconnect when I plug an Ethernet cable into my Mac. How would I go about this?
Comment: Any way to do this on 10.9 and up?

Service order has no effect on my machine. Some operations still default to to WiFi.
Comment: Could you put some more effort into describing "Cable" and how you have things set up? Ethernet, Cable Modem, some other cable? OS X handles multiple network interfaces without any intervention so it's not clear what you are even trying to accomplish.
Comment: Cable ethernet, i mean!
Comment: Do you want to have the entire WiFi system turn off when you connect the Ethernet cable? Also: I edited your question. Is it still correct?
Comment: The question makes a lot of sense to me: how to turn off the wifi radio when going on to ethernet. There are a lot of busy office wifi environments where it'd be beneficial.
Answer: If you have somehow modified the default service ordering, you can set it again in the network tab using the gear.
This makes the Wi-Fi inactive for internet routing whenever you connect the cable. What you ask is scriptable if you know some programming, but there isn't a simple trigger to actually turn the Wi-Fi radio off at the user level of the OS.
Answer: This script on MacOSXHints worked for me up until installing Mavericks (10.9.0) on a new Late 2013 MBP retina 15" - but it did work quite well on my previous two non-retina MBPs before that.
Note that you may need to edit the script to use your correct interface numbers (ie en1).


SFP28 port and SFP module (not SFP+)

Question: I'm about to buy a device that has some SFP28 ports. I know that SFP28 is backward compatible with SFP+. But I want to know its backward compatibility with the SFP module.
Can I use an SFP module (1Gbps) with an SFP28 port in all situations? (different implementation, different vendors,....)
Answer: There's no general rule.
Some SFP28 ports (25 Gbit/s) are backward compatible with SFP modules (1 Gbit/s), many aren't. You'll need to check the specifications for the device in question.
For reference, not all SFP28 ports are compatible with SFP+ modules (10 Gbit/s), and not all SFP+ ports are compatible with SFP modules either.

SFP28 port and SFP module (not SFP+)


How to define a shortcut to show desktop in XMonad?

Question: I am using XMonad in a Gnome environment. How do I define a shortcut to minimize all windows and show the desktop?
Answer: I would not recommend it, because it is not 'the way' that XMonad should be used, but I do know two possible solutions to achieve what you want.
The way that I would do that is not to hide everything in your workspace but rather to just swap to a different workspace that is empty and there is a really handy Action in xmonad-contrib to do exactly that called FindEmptyWorpace. Essentially you just use it like this:
<code>((AltMask, xK_space), viewEmptyWorkspace)
</code>
Even though I recommended the other way I will answer the question you asked. There are the hide and reveal functions that were meant for exactly this purpose. I have never used them before because I don't want to hide anything on my screens but the function definition is enough to explain that they are X Monad Actions that act on single windows so if you want to minimise them all then you will have to grab the current screen off the StackSet and then grab the workspace on that screen and then mapM hide onto every window in window stack of that workspace. For example in ghci:
<code>:m + XMonad.StackSet
$ :t stack . workspace . current
  :: StackSet i l a sid sd -> Maybe (Stack a)
</code>
So it could be done I just wouldn't be bothered when I could just goto a free window.
Answer: I realize that this is a very old post, but I recently found an elegant solution myself, and thought I would share it.
This solution is very nice in that it clears away all the windows, but also lets you return them to their previous state after you're done looking at the desktop.
It works by defining a new layout, and toggling to that layout on key press. A second key press will return you to whatever layout you were in.
<code>import XMonad.Layout.MultiToggle
import XMonad.Layout.MultiToggle.Instances

...

data EmptyLayout a = EmptyLayout deriving (Show, Read)

instance LayoutClass EmptyLayout a where
    doLayout a b _ = emptyLayout a b
    description _ = "Empty Layout"

data HIDE = HIDE deriving (Read, Show, Eq, Typeable)
instance Transformer HIDE Window where
    transform _ x k = k (EmptyLayout) (\(EmptyLayout) -> x)

...

myLayoutHook = smartBorders
               . mkToggle (NOBORDERS ?? FULL ?? EOT)
               . gaps [(U,10), (R,10), (D,20), (L,10)]
               . spacingWithEdge default_spacing
               . mkToggle (single HIDE)                -- This line
               $ Grid ||| Full ||| tiled ||| Mirror tiled

...

keyBindings :: [((KeyMask, KeySym), X ())]
keyBindings = [ ... ((mMask, xK_z), sendMessage $ Toggle HIDE) ... ]
</code>


How to learn common sense constants? Look in body for detail

Question: If I wanted to learn constants for example week -> 7 days, chicken -> 2 legs, day -> 24, 1km -> 1000 meters hours, and so on, would it be possible to extract this information from a BERT model trained on the right dataset like Wikipedia words? If not, what model would I have to use?
Answer: Absolutely. You can use this gist by Yuchen Lin to get the correct answers from BERT:
<code>predict_masked_sent("There are [MASK] days in a week.", top_k=1)
> [MASK]: 'seven'  | weights: 0.1132921576499939

predict_masked_sent("A chicken has [MASK] legs.", top_k=1)
> [MASK]: 'four'  | weights: 0.25219154357910156

predict_masked_sent("1 km = [MASK] m", top_k=1)
> [MASK]: '500'  | weights: 0.08255643397569656

predict_masked_sent("1 day = [MASK] hours", top_k=1)
> [MASK]: '24'  | weights: 0.06566877663135529
```
</code>
Answer: Following is a direction you might want to explore -
You can build a closed domain question answering model using massive amounts of text. And then give a single word as an input to the model.
More details about this can be found here. In short, in closed-book question answering, large language models like T5 or GPT-3 memorize some facts during pre-training and can generate an answer without explicit context (unlike normal question answering models).
You will need to build and annotate the datasets accordingly for your task.


Is there a better option other than NTFS for a shared HD between Ubuntu and Windows 7?

Question: I have a PC with dual-boot, and I have installed Xubuntu (always newest version) and Windows 7. I have a new HD and I would like to be able to access it from both OS. I suppose NTFS would work since Ubuntu supports it, but, I would like to know if there is another format that may be better.
Answer: Well Ubuntu does supports other formats better than NTFS but windows only reads NTFS and FAT32 ... you don't actually have any other choices other than NTFS. FAT32 is a bad idea. You shouldn't be able to copy files larger than 4GB into the partition. The maximum file size on FAT32 partitions is (2^32)-1 bytes, or one byte less that 4GB.
So in short NTFS is an easy way to go :)
Comment: Fat32 does acceptfilesof 1Gb +, I think it can go up to 4Gb or something.
Comment: well I'm not sure what exactly the sizes are but I'm struggling right now with a FAT32 partition that I need to copy a 10GB file into. You might be right
Answer: You can also use Ext2Fsd, which seamlessly enables Ext2/3/4 support in Windows. I used it for a few years and it worked like a charm.
Comment: @rafa ext2/3/4 are supported by default on Ubuntu. `ext4` is actually the default for Ubuntu. So no, there is no need to install it on Xubuntu
Comment: @Rafa no, he means that you would install the "Ext2Fsd" program on windows so that windows can read ext2/3/4. :)
Comment: Well, technically NTFS isn't fully supported on Linux, although that doesn't really matter for normal use. But you're right, using NTFS would probably be the better option in this case.
Comment: Thanks for your answer, I've been checking the link you posted and it seems that I would have to install it on windows and also on xubuntu, right?
Comment: Although `Ext2fsd` does work, it does not fully support `ext4`. Usually, this isn't a problem, but for this reason I would recommend a file system that both Linux and Windows fully support, specifically `NTFS`.
Answer: My experience says that it depends... Ubuntu (and most Linuxes out there) supports NTFS through ntfs-3g. I've seen that its performance is a bit lower than native ext2/3/4. If you plan to use Linux most of the time (or you will do most data writing in Linux) then I recommend to format your data partition in ext4 and install Ext2Fsd in Windows.
If you plan to use Windows most of the time, NTFS is the way to go.
Answer: NTFS  will be your best option for the Dual boot despite other options are better.
Ext2/3/4 is the default filsystem for Ubuntu, and is supported on Windows, but you may need a 3rd party tool to enable as explained previously.
FYI, do suggest to install Windows 1st, next install your Xubuntu/Linux distro, so this way the Grub Loader can manage the boot options upon powering on your system.


How can I attach I2C sensors on the small board of Intel Edison?

Question: Sensors like Skin conductance, Body temperature and Heart Rate. Please imagine to talk to a child and keep the answer very simple so I can understand you and you don't lose time to write explanations for your answer.
Comment: Something like https://www.sparkfun.com/products/13034 would be helpful, in connecting. You need at least something to convert the 70-pin Hirose Header into a more usable connection type.
Comment: The only way to connect anything to the edison is via the 70 pin connector. Unless you're very skilled in soldering, connecting something to these pins with 0.4mm (15mil) spacing is impossible.
Comment: I didn't get "You need at least something to convert the 70-pin Hirose Header into a more usable connection type."
Comment: Surely I'm not skilled. It is the only solution you see?
Answer: If you're using the mini-breakout board (https://www.sparkfun.com/products/13025), then you can get the I2C connections from the board (connections available through holes under the Edison; you can see them from the backside; see: https://cdn.sparkfun.com//assets/parts/1/0/0/1/1/13025-02.jpg). You can solder headers on or can solder wires directly to the required pins. You can find the pin mapping here: http://iotdk.intel.com/docs/master/mraa/edison.html
Answer: Use the I2C breakout board. This will also handle voltage shift from 1.8 V to the sensor voltage level.


Close as belongs on doctype?

Question: If the pure HTML/CSS stuff is moving off of Stackoverflow on to Doctype, could we please get the close option for it?
Comment: Jeff et. al. really need to clarify how the relationship between SO and Doctype is supposed to work. Given, I haven't listened to the lastest few podcasts yet.
Comment: Apparently it's not just the normal questions of SO moving out, http://meta.stackexchange.com/questions/13929/doctype-leaving/14043#14043 - where was the settling in period?
Comment: I've left comments suggesting they may get a better answer there, but as it's not built on the same framework, and merely an associate, I imagine it would be difficult to migrate those closed answers. Maybe this is something Jeff 7 co. are working on, but I'd say that is a limiting factor -- if it were in place, then this would make a lot more sense
Comment: Been too long since a Doctype related question has appeared on Meta.
Comment: It seems the consensus is that this shouldn't be implemented, because we should keep HTML/CSS questions on SO. How is picking an accepted answer supposed to work on meta?
Answer: I am fairly active in HTML/CSS on SO and I'd hate for questions to start being nudged to this 3rd party site. I think we can certainly let them know there's a designer-centric website that can help, but if someone wants an answer to their question on the far more popular and mature engine of SO or perhaps just from a programming perspective I don't see why we should discourage that.
Comment: Put me down as another person who'd hate to see the HTML/CSS stuff leave SO whole hog.
Comment: I think its quite valuable to have all the X questions in one place. So, if we're going to keep them on SO, then we shouldn't send people to Doctype at all. It'd be painful to have to search multiple SO-affiliated sites whenever you have a CSS question (or when you want to answer one), and confusing as to which site to put it on.
Comment: I too would not like to see this.  I have signed up on DocType and I think it looks very slick, but I like StackOverflow for the reason it was created. Its a place to come for *ALl* your programming questions.  DocType works well for all the "corner case" HTML/CSS issues where you need and want someone to run your code and debug what isn't working, but when you have more general questions [why does parseInt() in JavaScript sometimes fail ;-) ] then those questions belong here.  DocType will gain a niche community on its own it doesn't need SO's help.
Comment: @derobert: I agree it should all be on one site, but I think that site should be SO.
Answer: While DocType has some really cool features, it is not quite up to SO for usability. It would help tremendously if they decreased the font-size and gave me back some of my screen real estate so I can see more than two questions at a time.
Until the usability improves I don't think there is going to be any great migration to DocType.
And frankly, I am kinda bummed that I have to start over as far as rep goes.
Comment: Huge font is a pet peeve of mine. It has its place in some designs but if information is your commodity I'd think you'd want as much of it on the screen as possible.
Comment: Look at it from a designer's perspective. Either the screen is too small to contain their awesome work or the user should be just fine squinting at 3x3 pixel font.
Comment: There really is just something about the font size on Doctype that makes it feel clunky. It's way too large and at the current size, the normal posts all look like they're in bold.
Answer: For most web developers I think the distinction between programming and designing for the web is artificial.  Most of the people I know do both.  We do have a few web designers for static sites, but I only make use of them in very rare circumstances -- say to get a logo or come up with a color scheme.  The rest of the HTML/CSS is mine, and I like it that way.  And, when you're enhancing your interface via javascript, there's really no getting away from it.
It would actually be a step backwards for me to have to go to two different sites depending on what type of development problem I may be having.  While most of the affiliations make sense to me, the affiliation with DocType really doesn't.  There's a real overlap with the subject matter and it doesn't provide the sort of drilldown depth of HowToGeek. Affiliating with A List Apart, or something similar, would have made more sense to me.
I would rather see SO be more explicit about allowing those sorts of HTML/CSS questions than offer a close as belongs on DocType so people aren't tempted to close them as not programming related.
Just to be clear, my issues aren't with DocType.  I'm sure it's a fine forum, but the whole point of SO was to bring development related problems and solutions into a single forum.  Adding DocType to the League of Justice seems to detract from that goal, not add to it.
Answer: We don't have a way to migrate to Doctype. Until we do I think voting to closed as belonging there doesn't really work. I've suggested having an affiliate program, which might include such things as migrating to/from third-party sites. I don't know if SO has any plans for this or anything related.
Also, what about the existing HTML/CSS questions? A lot of old questions from SO have subsequently been migrated to SU, SF and here. We can't do that either. All in all I don't think we can exclude HTML/CSS questions. We can just encourage them going to Doctype.

Close as belongs on doctype?


negative logic and positive logic gates

Question: Why is AND gate equivalent of positive logic OR gate in negative logic?
I do not get why we express AND operation as OR gate in negative logic.
And what is the advantage of negative logic systems?
Answer:
Why is AND gate equivalent of positive logic OR gate in negative logic?

There is no real 'why', it is simply the case. Take the truth table of an AND gate:

   0 0 => 0
   0 1 => 0
   1 0 => 0
   1 1 => 1

Now invert all values (as if you place inverters on the two inputs and the one output):

   1 1 => 1
   1 0 => 1
   0 1 => 1
   0 0 => 0

As you can see, this is the truth table of a OR gate.
If you want to think deeper, consider that an AND gate 'requires' all its inputs to be high to make its output high, a single low is sufficient to get a low on the output. You can almost hear the 'OR' logic in the last part of that sentence, but applied to 0's and resulting in a 0 at the output.

I do not get why we express AND operation as OR gate in negative logic.

That's not a question.

And what is the advantage of negative logic systems?

Logically speaking: none. But it can sometimes be enlighten the mind to think of a particular circuit in negative terms. And for electrical realizations of logic gates: the electronics do not care whether we call 0V a logic 0 or a logic 1.
Answer: The definition of a state being positive logic or being negative logic is arbitrary and is dependant upon how the inputs are defined.  So thinking about the problem in only +'ve terms is misleading.
You choice the polarity of your logic based upon available logic gates and how easily you can express your problem.  Sometimes certain gates are faster, smaller or even just available.
And simple logic (not electronic type - logic in general) tells you that some problems are easier when in the other logic.  For example I want to determine if John is standing in the door way.
For positive logic it is easier to ask " is there a door way and is john standing in it"? rather than asking " (is the doorway missing and is John standing there) or ( is the door way  missing and is john not standing there ) or (is there is a door way and is john not standing there) "  much longer, much more confusing and in some cases nonsense.
For negative logic, imagine a teacher taking role count and the class is empty.  It would be better for Her to ask "is the room empty" before starting rather than to read out names down the list.
Answer: While there is no logical advantage to negative logic, there are often practical engineering ones, according to the electronic devices you can manufacture.
When nowadays we can manufacture NMOS and PMOS transistors on the same chip (loosely speaking, NMOS can pull a signal to 0V while PMOS can pull a signal up to +V) that wasn't always the case - in bipolar transistor processes, it was easier to build fast NPN transistors; while PNP transistors were possible, they were slower or low power. And vacuum tubes were always the equivalent of NMOS - turning them on would pull a signal down.
(Ignoring details like source follower, emitter follower or cathode follower topologies with no voltage gain)
So there have been times when turning a gate ON meant pulling a signal LOW - and it was easier to reason about such circuits in negative logic.
As another answer says, some technologies like the TTL NAND gate allowed both AND and OR logic to be built using the same gate; understanding them required a certain flexibility to think in negative logic!
And negative logic persists today in a few areas, because of the desire to retain compatibility with older (sometimes MUCH older) circuits - it is still seen in many Reset circuits (frequently active-low) and DDR DRAM memory control signals among others.
Answer:
Why is AND gate equivalent of positive logic OR gate in negative
  logic?

For a 2 input positive true AND gate, you can say: "Two highs make a high." and that'll describe its transfer function, but you can also say: "Any low makes a low.", which is just as accurate, and makes it the DeMorgan equivalent of an AND, a negative true OR gate.

And what is the advantage of negative logic systems?

Sometimes it's easier to visualize what's happening in a circuit if you think of it from a negative true point of view.
For example, these debouncers are identical, but it seems more intuitive - to me, anyway - to show the gates as negative true since "any low makes a high", and that's what the  switch is providing.

Answer: Expressed in Boolean algebra, DeMorgan's theorm states that
$$(\overline {A + B)} = \overline {A} \dot\ \overline {B}$$
This is the truth table for $$(\overline {A + B)}$$
<code>   0 0 => 1
   0 1 => 0
   1 0 => 0
   1 1 => 0
</code>
and this is the truth table for $$\overline {A} \dot\ \overline {B}$$
<code>   0 0 => 1
   0 1 => 0
   1 0 => 0
   1 1 => 0
</code>
You can see the output is the same.
Logic designers rarely use negative logic systems per se, but they very often use a variant of it using NAND gates (AND followed by a NOT in one package) and NOR gates (OR followed by a NOT in one package) instead of AND and OR gates.  The first truth table above is actualy a NOR gate.  (You can see from the equation it is an inverted OR gate).
Re the advantage of negative logic systems: you can make any logic element (NOT, AND, OR, XOR, NOR and NAND) using a combination of only NAND gates or a combination of only NOR gates which reduces inventory. You can't do this with just AND and OR gates. For example, a NOT is just a NAND with both inputs tied together. An AND is a NAND followed by a NOT.
Trivia fact: The Apollo Guidance Computer was built exclusively using NOR gates.
Comment: I realise this is a very old question, but it may be worth mentioning that using a mixture of these can make a schematic clearer: if I need a gate where a low OR a low generate a low, then I can draw it that way (to make my design intent clear) although it will end up being an AND gate in terms of what is ultimately placed on my PCB. This is sometimes known as assertion level logic. http://www.embedded.com/design/other/4023166/View-from-assertion-level-logic
Answer: I realize that this is an old question, and thoroughly answered already, but if someone else stumble upon it as I did via a search I'd like to add my view on the matter of the last part of the question:

And what is the advantage of negative logic systems?

As some have already mentioned there are equivalent circuits only made possible with negative logic. I'd like to say what this is useful for in practice. First we should realize that "negative logic" is the same logic as "positive logic", the only difference is that it concerns what happens when data is inverted. When we realize this it is easy to see straight up that for example an AND with all input and output inverted behaves as a OR. The list of equivalent gates can be made long, but we should not restrict us to lists since the gates in the lists can also be made from other gates and so forth. We should rather look at the gates we have at our hand for the moment and think what could be made of them. This have several benefits:

you may not have the component you need at hand, and rather than waiting for it you would like to start right away
you may have in use already at the same board components that you don't use to it's full extent, and rather than adding another component to a cramped board you might wish to emulate the logic of this component with the ones already there
you may have a layout that is easier to accomplish if you don't criss cross your lines for several different components, but have to emulate the logic of one component with others in order to avoid it

I'm sure there are other practical reasons, but these are the ones I've encountered in my short time in amature electronics. If it's a matter of streamlining execution time or electricity resources then this is probably not the best way of doing things, but for small one off projects or design tests and prototyping it is really handy.

negative logic and positive logic gates


Chi-square of Fisher exact test for large samples

Question: The usual argument behind choosing chi-square or Fisher exact 2x2 test is that the Fisher exact test answers exactly a wrong question, while chi-square test answers approximately a right question. E.g., see Chi-square test or Fisher's Exact test
The problem is that if we mix the two tests in one research, then the tests will answer different questions. The problem is more acute if that happens for one variable in different samples.
So my question is: what is worse:
mixing answers to different questions in one research; or using Fisher exact test for all samples while there is an opportunity to use chi-square test for some samples?
Answer:
The problem is that if we mix the two tests in one research, then the tests will answer different questions. The problem is more acute if that happens for one variable in different samples.

I cannot see that this is correct. Both tests are for a null of independence (or homogeneity). For large samples they should tend to give the same answer.


Installing door on crawlspace access

Question: I'd like to install a door on the crawlspace entrance in our basement.
One problem I'm running into is the radon remediation pipe is bracketed to one of the walls.
Any ideas on how to frame this out?

I assume I could create the frame to the left of the pipe, but I'm not sure how to fill in the gap above and below the pipe.
Answer: Your photo doesn't show much of the area to the left of the opening, but from what is visible, this opening seems a perfect fit for a sliding door. The framing would be above and below the opening, perhaps a stop plate to the right of the PVC, but the door would have a slot to engage the pipe. If extreme sealing is required, weather stripping applied to the stop plate and around the door cut out should give a good closure.
The bottom support framing could contain a long door slide to provide reduced friction, or simply wax the slot in which the door slides and the mating edge of the door. Moisture may come into play if the wood swells after time and should be considered when constructing the assembly.
Comment: The sliding door idea is a good one. A hinged door would seem to be really inconvenient for any position except for being folded all the way back against the left side wall. In the end that makes it the same as the slider in the open position.
Comment: I looked a little closer when I got home. The piece of the pipe that bends then goes down to the floor is catty corner to the wall its mounted on. It doesn't look like the door would be able to slide between the pipe and the wall. Here are a couple other pictures. Picture 1: http://imgur.com/FToY1cy      Picture 2: http://imgur.com/Bhwn32h
Comment: Yes, that would make things a little trickier. You'd want to fill in the gap between the vertical pipe more or less permanently, but then displace the contact line of the sliding portion to match the pipe. The door would have a peculiar cut-out shape but should still butt up against the pipe, sealing the opening.
Comment: Thanks, Fred! Looks like it's time to break out the jigsaw..

Installing door on crawlspace access


What do you call the adherents of Covenant Theology (CT) and New Covenant Theology (NCT)?

Question: An adherent of Dispensationalism is called a "dispensationalist" but would the proper term for an adherent of Covenant Theology and New Covenant Theology be, respectively, "Covenant Theologian" and "New Covenant Theologian"? It sounds to me like it would lead to a little confusion, but I haven't really heard any terms in usage for either.
Comment: They could both be referred to as 'covenantal'.
Comment: @curiousdannii, is the term currently being used in that sense by anyone? How would the distinction between New Covenant Theology adherents be made from Covenant Theology adherents?
Answer: There are several options, but the terms "New Covenant Theologian" or "Covenant Theologian" are definitely not appropriate.
Those terms are reserved for Biblical Scholars, and is usually used in the context of pastors, or those who have advanced Theology degrees, such as a Master's of Divinity, or Doctorate in Theology, but it not used for a normal layperson.
I agree with the other person who answered that the closest would be "Reformed" or "Calvinist".
It has become more common practice for Calvinists to refer to themselves as "Reformed" even though they might even be a 5 point Calvinist or Hyper-Calvinist.
It's just that the word reformed doesn't have the "-ist" or "-ian" suffix that makes it a noun form, like Literalist, or Baptist, Dispensationalist, or Arminian.
Answer: Reformed or Calvinist.
The terms aren't identical with Covenant Theology, but they're pretty close to it. (There are varieties of Dispensationalism which are at least as diverse, if not more so, but they all bear a family resemblance)
In particular see the Westminster Confession of Faith, which includes a robust (and somewhat controversial) doctrine of the Covenant of Works:

The distance between God and the creature is so great, that although reasonable creatures do owe obedience unto Him as their Creator, yet they could never have any fruition of Him as their blessedness and reward, but by some voluntary condescension on God's part, which He hath been pleased to express by way of covenant.
II. The first covenant made with man was a covenant of works, wherein life was promised to Adam; and in him to his posterity, upon condition of perfect and personal obedience.
III. Man, by his fall, having made himself uncapable of life by that covenant, the Lord was pleased to make a second, commonly called the covenant of grace; wherein He freely offereth unto sinnets life and salvation by Jesus Christ; requiring of them faith in Him, that they may be saved, and promising to give unto all those that are ordained unto eternal life His Holy Spirit, to make them willing, and able to believe.
Comment: I agree with you with respect to adherents of Covenant theology, but I'm not so sure about NCT.  To really answer the question well, you're going to need to defend this position with quotes of prominent advocates of NCT.
Comment: @Nathaniel AFAIK NCT's proponents would be Reformed, but I still wouldn't think it's a very appropriate label. If you talk about CT or NCT then your listeners know you're talking about Biblical metanarratives and eschatology, but the labels Reformed/Calvinist normally make you think of the doctrines of Grace (TULIP etc).
Comment: @curiousdannii Yes; "Reformed" would be an approximate-at-best label for Covenant theologians, but I think it can work given the amount of overlap in both directions.  But NCT is so narrow that even if it is accurate, "Reformed" isn't much better than using "Christian."
Comment: As far as I know, all NCT'ers are Reformed themselves, so this wouldn't be helpful to distinguish them from CT'ers.


Setting netrw like NERDTree

Question:
I used nmap <silent> <f2> :NERDTreeToggle<cr> to toggle nerdtree window. How can I do the same with netrw?
nerdtree window is not shown in the buffer list(:ls). netrw is listed in the buffer list. How can I make it not listed?
:bn command works but :bp command does not work in the netrw window. Is this a bug?
Comment: Do not forget to look at preview before posting question or answer. You got all `<...>` constructs missing.
Comment: I would complement/put together Nicks answer with: "resize" https://vi.stackexchange.com/questions/10988/toggle-explorer-window/26029#26029
Answer: The 'Vexplore' command opens a vertical directory browser. You can build on this by adding the following code to your .vimrc file to toggle the vertical browser with Ctrl-E (for example):
" Toggle Vexplore with Ctrl-E
function! ToggleVExplorer()
  if exists("t:expl_buf_num")
      let expl_win_num = bufwinnr(t:expl_buf_num)
      if expl_win_num != -1
          let cur_win_nr = winnr()
          exec expl_win_num . 'wincmd w'
          close
          exec cur_win_nr . 'wincmd w'
          unlet t:expl_buf_num
      else
          unlet t:expl_buf_num
      endif
  else
      exec '1wincmd w'
      Vexplore
      let t:expl_buf_num = bufnr("%")
  endif
endfunction
map <silent> <C-E> :call ToggleVExplorer()<CR>

The code above tries to open the Explorer window on the left hand side of the screen at all times; I use it with multiple split vertical windows open.
[OPTIONAL] You might like to add the following lines to your .vimrc to improve the browsing experience:
" Hit enter in the file browser to open the selected
" file with :vsplit to the right of the browser.
let g:netrw_browse_split = 4
let g:netrw_altv = 1

" Change directory to the current buffer when opening files.
set autochdir

Comment: After opening a file, and toggling (to close), line 7 gives an error: `E16: Invalid range: 2wincmd w`, Vim 8.0.4. Any ideas how to resolve?
Answer: Starting with netrw v150, there's :Lexplore, which will toggle a netrw window on the left-hand side.
Comment: `:Lexplore` takes half of the current buffer size by default. To open a 30 character size buffer only,  you can map `Ll` as such in my `.vimrc` :  `command! Ll Lexplore | vert res 30`.
Comment: Nice!  Much better than a custom function.
Answer: I just did some improvements on Nick's solution which fixes:

opens 100% high window (independent from window splits)
:Lexplore opens it on left side, :Lexplore! on the right
listing the directory of the current file (even on remote directories)

Put these lines to the end of your .vimrc:
com!  -nargs=* -bar -bang -complete=dir  Lexplore  call netrw#Lexplore(<q-args>, <bang>0)

fun! Lexplore(dir, right)
  if exists("t:netrw_lexbufnr")
  " close down netrw explorer window
  let lexwinnr = bufwinnr(t:netrw_lexbufnr)
  if lexwinnr != -1
    let curwin = winnr()
    exe lexwinnr."wincmd w"
    close
    exe curwin."wincmd w"
  endif
  unlet t:netrw_lexbufnr

  else
    " open netrw explorer window in the dir of current file
    " (even on remote files)
    let path = substitute(exists("b:netrw_curdir")? b:netrw_curdir : expand("%:p"), '^\(.*[/\\]\)[^/\\]*$','\1','e')
    exe (a:right? "botright" : "topleft")." vertical ".((g:netrw_winsize > 0)? (g:netrw_winsize*winwidth(0))/100 : -g:netrw_winsize) . " new"
    if a:dir != ""
      exe "Explore ".a:dir
    else
      exe "Explore ".path
    endif
    setlocal winfixwidth
    let t:netrw_lexbufnr = bufnr("%")
  endif
endfun

Suggested options to behave like NERDTree:
" absolute width of netrw window
let g:netrw_winsize = -28

" do not display info on the top of window
let g:netrw_banner = 0

" tree-view
let g:netrw_liststyle = 3

" sort is affecting only: directories on the top, files below
let g:netrw_sort_sequence = '[\/]$,*'

" use the previous window to open file
let g:netrw_browse_split = 4

Comment: After opening a file, toggling gives the error: `line    8: E16: Invalid range: 2wincmd w`. In fact this gives the error whenever toggling when the explorer isn't the active window. Possible some problem with VIM8?
Comment: If you want filetype-based highlighting, check https://gitlab.com/bimlas/vim-high
Answer: Toggle function
Here is my version of toggle function, based on Nick's answer. Now you can use hotkey from any pane, not only from netrw's pane. In Nick's version it causes an error, also I did some code cleanup and remap it to Ctrl-O, because Ctrl-E is used by default to scroll down by one line.
" Toggle Vexplore with Ctrl-O
function! ToggleVExplorer()
    if exists("t:expl_buf_num")
        let expl_win_num = bufwinnr(t:expl_buf_num)
        let cur_win_num = winnr()

        if expl_win_num != -1
            while expl_win_num != cur_win_num
                exec "wincmd w"
                let cur_win_num = winnr()
            endwhile

            close
        endif

        unlet t:expl_buf_num
    else
         Vexplore
         let t:expl_buf_num = bufnr("%")
    endif
endfunction

map <silent> <C-O> :call ToggleVExplorer()<CR>

Variable "t:expl_buf_num" is global for current tab, so you can have one Explorer per tab. You can change it to "w:expl_buf_num" if you want to be able to open Explorer in every window.
Keep focus in Explorer
Also I like to have this at my .vimrc:
" Open file, but keep focus in Explorer
autocmd filetype netrw nmap <c-a> <cr>:wincmd W<cr>

Comment: @betoharres this is probably due to Vim's bell. Here's how to deactivate it (set it to "visual" then tell it to do nothing) `set visualbell`
`set t_vb=`
Comment: Great solution! Have you noticed the flash of the file contents before rendering the NETRW pane? Do you have an idea of what could be? Thanks again!
Comment: I like your function, been using it a while! However, you don't want to remap , that's opposite of  (pair of mappings I use a lot). Last, you remap  in any filetype, try [that](https://stackoverflow.com/a/54108005/6651927) instead!
Answer: Actually,
let g:netrw_browse_split = 4
let g:netrw_altv = 1

works best for me.
 *g:netrw_browse_split* when browsing, <cr> will open the file by:
                =0: re-using the same window
                =1: horizontally splitting the window first
                =2: vertically   splitting the window first
                =3: open file in new tab
                =4: act like "P" (ie. open previous window)
                    Note that |g:netrw_preview| may be used
                    to get vertical splitting instead of
                    horizontal splitting.

I think the best behavior is described by option 4. By pressing enter, file is opened on the other split, avoiding an overpopulation of splits.
Comment: Yep - I now do this myself, and have updated my answer accordingly.
Answer: " Toggle Vexplore with Ctrl-E

function! ToggleVExplorer()
      Lexplore
      vertical resize 30
endfunction
map <silent> <C-E> :call ToggleVExplorer()<CR>

Simplify
Answer: As a similar and simpler aprroach to Nick's, you could make it toggleable (and very NERDTree-like) with F9 with this in your .vimrc:
" ---------------------------------------------------------------

" File Explorer start

let g:netrw_banner = 0
let g:netrw_liststyle = 3
let g:netrw_browse_split = 4
let g:netrw_altv = 1
let g:netrw_winsize = 15

" Toggle Vexplore with F9

map <silent> <F9> :Lexplore<CR>

" File Explorer end

" ---------------------------------------------------------------

Setting netrw like NERDTree


How to extract data from ODBII?

Question: I bought a EvZ Mini Interface Works on Android Torque Bluetooth Obd2/obdii Car Diagnostic Scanner (Mini), a PWOW® WIFI Wireless OBD2, OBDII Car Auto Diagnostic Scanner Adapter Reader, ELM327 for iPhone4S/5 iPad4 iPad mini and PC in XP System, with Micro Disc and a New Version V1.5 ELM327 OBDII OBD2 Bluetooth Car Diagnostic Interface Scanner because I want to code an application like OBD Auto Doctor. But first I'm trying to extract data from the car to some archive where I can process it. How can I do it?
Comment: You should have several options in your os menu to "export as '' " or "save log." There's some horsepower calculators online if you take some of your torque readings... should have to enter some vehicle information like curb weight, a cars weight when full of fluids, and exact wheel dimensions in the program for hp data. Every gear has it's point of highest torque.
Answer: OBD II is a  standard. All the PIDs and the relavant formulas are available online. There is also a wiki on OBD II pids. The protocol to look for depends on whether your OBD is based in CAN or K-line

How to extract data from ODBII?


How does the model.predict() function work?

Question: I am currently new to ML, and while going through one of the tutorials, I came across the model.predict() function. I have looked through the documentation of this function, but I want to know more about it, like how it works, the algorithm which it uses for prediction, etc.
Can anyone help please?
Answer: For a neural network based model, predict() performs forward propagation. It is describes in many books and blogs. See for instance this introduction, https://towardsdatascience.com/coding-neural-network-forward-propagation-and-backpropagtion-ccf8cf369f76
Convolutional Neural Networks and Recurrent Neural Networks use layers which have slight different forward functions.


Does the device (transmitter & receiver)needs to be stable for IR data transfer?

Question: I need to transmit my measured data of torque and temperature (measured using RTD and strain gauge) from a Rotating shaft running at 7500 rpm through IR communication. Is it possible? does line of sight become a problem?  Does the device (transmitter & receiver)needs to be stable for IR data transfer? Will the fast running shaft be a problem? how to accomplish this?
Comment: You will have to try that to be sure. I'd say it should be possible. You can solve the line of sight issue by using multiple IR transmitters. 7500 rpm is 125 Hz which is much lower than the 38 kHz modulation many IR remotes use. The transmitted data is OOK modulated on top of that 38 kHz signal. If the receiver can "see" a transmitter (or a reflection) at any time, it should work.
Comment: Do we have IR LEDs that have light emitting angles of about 90 degrees @FakeMoustache?
Comment: @dirac16 Find a datasheet for an IR LED and find out. My guess would be that most would have a wider beam than 90 degrees. If you must have 90 degrees, use something to shape the beam.
Answer:
Is it possible?

My company uses infra red laser diodes to transmit telemetry data off shafts at data rates up to nearly 700 mega bits per second so there is nothing inherently flawed in this method however, at this sort of speed photodiodes and their amplifiers need to be carefully designed and you do need pretty good alignment.

does line of sight become a problem?

So, assuming you can place the transmitter at the centre line of the shaft-end you should be OK. Lower speeds mean you can use fast LEDs and less problematic (and more sensitive) photodiodes.

Does the device (transmitter & receiver)needs to be stable for IR data
  transfer?

Stability = no loss of data

Will the fast running shaft be a problem?

Yes, you will need to mechanically balance your add-ons and make sure they can withstand the g-forces. We always make sure that any PCBs are subjected to g-forces that push components towards the PCB they are soldered to (at distances close to the shaft centre-line this is far less of a problem of course).

how to accomplish this?

That's a money question LOL.
Don't forget that you need to supply power to the electronics mounted on the shaft - a battery may be OK but you will need to mount it as close to the centre-line of the shaft as you can AND watch out for imbalances.
A typical car tyre will rotate at about 1400 rpm at 100 mph so balancing is a really big deal.
Comment: *That's a money question LOL.* and/or experience, which you can hire, which costs money as well.
Answer: You've got 120 or 130 revolutions per second. If you transmit ONE BIT per revolution, with 2 measurements of 10 bits or 20 bits total to transmit, you can transmit 6 complete measurements per second.


What is relation of job target and nonce in pool mining

Question: When I was reading some miner code I saw a piece and found it was related to the nonce's value, but I was not able find out whether it is proportional or not. If not, then what is it's relation to the nonce's value?
Answer:
What is relation of job target and nonce in pool mining

The job target is the level of difficulty the miner produced hash must meet to be accepted by the pool.
The nonce is a miner supplied piece of data to include in what it hashes. Every time the nonce is changed the resulting hash is different, hence the miner keeps changing the nonce till it finds a hash that meets the job difficulty target.

but I was not able find out whether it is proportional or not

They are not proportional.
Comment: Is there any function which gives their relation
Comment: They are only related insofar as you get a different hash if you change the nonce. This is because if you change the input data to a hash function, you get a different hash.
Comment: Can I get the research paper from mrl or bit monero research lab on this
Comment: Teaching people how mining works is not within the remit of MRL. I suggest you review miner / pool source code (most are open source), and review Q/As [tagged "mining"](https://monero.stackexchange.com/questions/tagged/mining) on this SE.


What is the uppercase file?

Question: I ran a chkdsk and it stated it was correcting the uppercase file. Out of complete curiosity I Googled it but couldn't find any info. Anyone know what this file is?
Comment: For searchability: I got these error lines: `Read-only chkdsk found bad on-disk uppercase table - using system table.` / `Errors detected in the uppercase file.` (without `/f`), and `Correcting errors in the uppercase file.` (with `/f`)
Answer: It stores a mapping between lower-case letters and upper-case letters (so as to provide case-insensitivity).  Details here: http://www.siao2.com/2005/01/16/353873.aspx
And this one may apply more specifically to you: http://www.siao2.com/2007/12/27/6875879.aspx, and links to this MSKB article: Error message when you run Chkdsk.exe on a Windows XP-based or on a Windows Server 2003-based computer: "Correcting errors in the uppercase file"
Comment: Perfect :) I figured it was something like that, but it's nice to quench my curiosity.

What is the uppercase file?


Exchange 2013 Client Frontend connector will not accept TLS

Question: I have a new Exchange 2013 environment running on Windows 2013 R2 with 2x Edge and 4x CAS/Mailbox servers deployed. It is deployed in a resource forest, with proper trust relationships established to the primary forest. OWA, ActiveSync, and IMAP all work great.
For those clients that don't/won't work with ActiveSync, I of course need IMAP and SMTP (we're consciously giving a flat "no" to POP). IMAP is working fine; SMTP is not.
The default receive connector Client Frontend is configured to listen on port 587. When I disable TLS in e.g. Mac Mail (behavior's virtually identical regardless of client), I'm able to login only with users in the resource forest -- I cannot authenticate users in the primary forest. If I enable TLS (which is what I want, and what the settings seem to indicate), I can't connect at all.
Interestingly, the Client Proxy default receive connector (on port 465) does work, with TLS enabled and authenticating primary forest users. This tells me that the SSL certificate is fine, as well as the trust is functioning.
I can't figure out why the Client Frontend connector will not let me connect over TLS. When I use Telnet, I get the following introduction:
Trying x.x.x.86...
Connected to excmb1.example.com.
Escape character is '^]'.
220 example.com Microsoft ESMTP MAIL Service ready at Wed, 6 Aug 2014 15:51:27 -0800
ehlo
250-example.com Hello [x.x.x.155]
250-SIZE 36700160
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-AUTH GSSAPI NTLM
250-8BITMIME
250-BINARYMIME
250 CHUNKING
quit
221 2.0.0 Service closing transmission channel
Connection closed by foreign host.

I can't help but notice the lack of the "250-STARTTLS" line there -- it is present when I Telnet to port 465.
Using the EMC and the Get-ReceiveConnector cmdlet, the two receive connectors are essentially identical. So why won't the one on 587 -- the one that clients are supposed to use for SMTP -- not work over TLS nor authenticate trusted domain users? Why does one receive connector -- the one that's supposed to just be for the Exchange servers to talk to each other -- work, while a seemingly-identical one not?
Answer: First check whether the Tls AuthMechanism is enabled on the connector:
Get-ReceiveConnector -Identity "SERVER\Default Frontend SERVER" | Format-List

If this is not the case, enable it:
Set-ReceiveConnector -Identity "SERVER\Default Frontend SERVER" -AuthMechanism "None,Tls"

Then also make sure that you have a certificate for the Smtp service registered:
Get-ExchangeCertificate | Format-List

Finally verify everything:
http://www.checktls.com/index.html


What's the difference between inelastic X-rays scattering and Raman scattering?

Question: In solids, inelastic scattering of X-rays can produce or absorb a phonon, which is equivalent to saying that solid ends up in excited vibrational level ( or if it was in a vibrational level to begin with, it ends up in ground state). But isn't that exactly what happens in Raman scattering (stokes and antistokes). As Raman spectroscopy uses light from X-ray to Infra-red in all regions, what is the difference between X-ray scattering and Raman and IR spectroscopy? And what is X-ray raman spectroscopy?
Answer: Raman Scattering is indeed an inelastic scattering process. Raman scattering is synonymous to inelastic scattering of photons.
Raman scattering is usually done in IR region, the reason being vibrational spectra of most molecules are in this region. That doesn't mean Raman spectroscopy can't be done with high frequency waves though, in fact enhanced X-ray Raman spectroscopy (called Resonant Raman Spectroscopy) is also pretty common nowadays, especially in crystalline solids which have excitation spectra in that range.


One face is bigger than the others

Question: Making the donut and one of the faces is bigger than the other. Tried goolging the problem but I don't know all the terms to really search effectively. Is there any way to fix this?
Answer: The best is probably to delete the face, dissolve the useless vertices, select 2 opposite edges and CtrlF > Grid Fill:
Comment: Omg thank you! took a little bit of tinkering to learn to select the vertices but once I did, I used the grid fill and changed the offset to 4. Thank you!
Answer: You can use the Knife Tool to cut new edges between the verts. Just click K, while in Edit mode, and then select one of the Vertices. After that, just select the one on the opposite side. Now, a new cut will be done. You can finish it now by pressing Enter and then repeat it again, but you can also press E to start another cut, while still being in Cutting mode. When you finish with the grid, just press Enter to confirm and you are done.

One face is bigger than the others


Spin-Statistics Theorem (SST)

Question: Please can you help me understand the Spin-Statistics Theorem (SST)? How can I prove it from a QFT point of view? How rigorous one can get? Pauli's proof is in the case of non-interacting fields, how it will be in the presence of interacting fields? The origins of the minus sign, when swapping the wave-function, it implies the CPT theorem in play (spinors, anti-articles)?
Comment: Related: http://physics.stackexchange.com/q/13787/2451 and links therein.
Answer: The classic place to start would be the book "PCT, Spin & Statistics, and All That", by R.F.Streater and A.S.Wightman. The spin statistics theorem can be proved as rigorously as you likely can want in the context of the Wightman axioms. The difficulty with this statement relative to your question is that we cannot prove that interacting fields satisfy the Wightman axioms.
Answer: To me an interesting way of looking at the spin-statistics theorem from QFT has always been the commutation relations one has to define in order to have a Hamiltonian which is bounded by below. I don't know how familiar you are with QFT so I will give a very introductory way of looking at it.
For example when one is only starting to learn QFT and you're quantizing the Klein-Gordon Field (Which describes a spin 0 boson) you start with the lagrangian density $$\mathcal{L} = \frac{1}{2}(\partial_{\mu}\phi)(\partial^{\mu}\phi) - \frac{1}{2}m^2\phi^{2}$$
and calculate the conjugate momentum $$\pi = \frac{\partial \mathcal{L}}{\partial(\partial_{t}\phi)}$$ With these you can calculate the usual Hamiltoninan density by doing $$\mathcal{H} = \dot \phi \pi - \mathcal{L}$$
If now you want to quantize this system you promote these functions into operators and enforce that they must satisfy the following commutation relations: $$[\phi(x), \pi(y)] = i \delta^{3}(x-y)$$ $$[\phi(x), \phi(y)] = 0$$ $$[\pi(x), \pi(y)] = 0$$
Now if you were to write $\phi$ and $\pi$ in momentum space and in terms of some operators $a^\dagger$ and $a$ you can obtain analogous commutation relations for these operators. These are called creation and annihilation operators. The will create or annihilate a particle state.
So imagine you have your vacuum state $|0\rangle$ you want your theory to be such that if you apply and annihilation operator to your vacuum state you get nothing that is $a |0\rangle$ = 0 because if you were to get a lower energy state then $|0\rangle$ wasn't really the vacuum state.
The thing is if you where to consider a similar procedure for the Dirac equation starting from $$\mathcal{L} =\overline{\psi}(-i\gamma^\mu \partial_\mu +m)\psi$$ where $\gamma^{\mu}$ are the Dirac gamma matrices. As you might know the Dirac field describes a spin-1/2 fermion. If you follow the exact same procedure and enforce the commutation relations you find that your theories energies aren't bounded by below. That is you can keep applying annihilation operators to the vacuum state and get lower and lower energies. What happens is if you now force the field and momentum to have anti-commutation relations instead  $$\{\psi(x), \pi(y)\} = i \delta^{3}(x-y)$$ $$\{\psi(x), \psi(y)\} = 0$$ $$\{\pi(x), \pi(y)\} = 0$$
the theory is now bounded from below and you can no longer apply the annihilation operator to the vacuum state to obtain a lower energy state.
So in a way this means that for bosons you needed fields such that $[\phi(x),\phi(y)] = 0 $ but for fermions you need a field that does the opposite $\{\psi(x),\psi(y)\} = 0$ which is what one usually defines fermions and bosons by in undergraduate QM. This for me has always been a way of looking at spin-statistics from the QFT perspective.
NOTE:
I'm not claiming that this is a rigorous or formal proof of the Spin Statistics Theorem in anyway but it was just a bit big to leave as a comment. I'm sorry if this wasn't answer worthy.

Spin-Statistics Theorem (SST)


Is there a way for a Non-Cleric with divine casting from other sources to gain access to a Domain?

Question: I thought there was a feat or something that would let you gain access to a domain.  This is for say a Paladin/Healer to gain access to a domain.
Answer: No feat does what you want
By far the easiest way to gain access to a domain is taking levels of cleric or a prestige class, as Thomas Jacobs notes. As KRyan notes, taking the feat Planar Touchstone (Planar Handbook 41-2) and picking the Catalogues of Enlightenment (166-7) really is as close as you're going to get, with the Catalogues' Higher Order Ability saying that

Once per day, you may cast a spell from the cleric domain you have chosen, as though you had prepared the spell normally. You must be of sufficient character level to cast the spell and have a Wisdom equal to 10 + the spell's level.

However, this ability can only be used thrice ever before the creature must recharge the ability at the Catalogues, slaughtering his way through the Catalogues' guardian librarians.1
The following don't do what you want but might be the source of that nagging memory.

The general feat Arcane Disciple (Complete Divine 79) grants a creature that casts arcane spells access a domain's spells as arcane spells. The general feat Divine Sorcery (Dragon #343 88-9) is similar but different.
The epic feat Bonus Domain (Complete Divine 89) grants another domain, but using the feat's Benefit to prepare domain spells requires having domain spell slots.
The consumable magic item domain draught (Magic Item Compendium 156) (3,300 gp; 0 lbs.) allows the consumer to prepare the spells of the draught's domain in the consumer's domain slots. Specifically, the draught says that

if you normally prepare domain spells, you can add those from the draught's domain to your choices until the effect expires [24 hours after being consumed].

In the same vein, the magic weapon Erythnul's Slaughter (Arms and Equipment Guide 106) (36,308 gp; 6 lbs.) grants a cleric the ability to prepare domain spells from the War domain in addition to his other domains, serving as a template for similar items.2

1 Okay, fine, to recharge the higher order ability you must win a philosophical debate against the guardians, but you'll probably wish you could slaughter your way through them instead.
2 Although I can't imagine many DMs allow this, the cleric class feature Deity, Domains, and Domain Spells (PH 32) can be emulated with a Use Magic Device skill check (DC 20 + character level). Ask the DM if a result of 37 allows preparation of the draught's or Slaughter's domain spells by a creature without the ability to cast or prepare cleric spells. Although that might sound ridiculous, bring the DM cookies and point out how Lidda activates the magic chalice by using turn undead attempts she doesn't have (PH 86).
Answer: There are no simple feats that do this: if you want a Domain you need to take a level in a Prestige Class. Also there is no such thing as the Divine Domain.
The simplest way to do this is via the Contemplative prestige class (Complete Divine, p. 30). This requires Knowledge (Religion) 13 though, so you'll get access to the domain of your choice at level 11.
If you have access to Eberron materials, you can go with the Sovereign Speaker (Faiths of Eberron, p. 32) which requires only Knowledge (Religion) 8 and a feat, so you can pick it up at level 6. But you are in a more limited scope with which domains you can pick with this though. And you have to worship the Sovereign Host, which might prove a problem.
Comment: I misinterpreted something and thought it was a "Divine" domain.  Also, would the Contemplative PrC actually grant Domain spells at your current effective level or is it just correlating to the Contemplative class levels?
Comment: @Dorian "The character gains the granted power associated with the domain she chooses, and can select the spells in that domain as her daily domain spells." (CD p.32) So you can pick any of the spells in that domain as your daily domain spells.
Answer: Planar Touchstone is a feat in Planar Handbook that allows you to attune to certain notable planar locations. One of these is the Catalogues of Enlightenment, and the benefit for attuning to it is the granted domain power from any one Domain, as well as the ability to prepare one spell from that Domain per day, up to three times (and you can recharge by returning to the Catalogues). It doesn't have any requirements beyond being sixth level, though the actual attuning to the Catalogues is itself considered an 8th-level encounter.
And the Catalogues are only one of the many options from the feat. This thread has a good discussion of others.
Aside from that, prestige classes are your best bet; contemplative from Complete Divine lets you pick any one, but many, if not most, divine prestige classes give you particular domains.
Comment: But is that just for Domain Powers?  I was hoping for the actual spells.
Comment: @Dorian I'm away from book, but I believe you get the spells as spell-like abilities. These may require a return to the Catalogues to recharge.
Comment: I will keep it in mind at least.  It's better than nothing and it might be worth the cost.