Speed of a falling object

Question: When an object is dropped, does it accelerate to terminal velocity? or is it at terminal velocity immediately?
Comment: Nothing is immediate in real life.
Answer: Conceptually, it depends on the type of object that is dropped. If the object is highly affected by air (wind) resistance ( like a feather or tissue) , terminal velocity will occur almost immediately after it is dropped. Acceleration due to freefall is still 9.8 m/s2 in any case, but air resistance will kick in and terminal velocity will occur amost immediately. For objects with almost no air resistance, terminal velocity will occur immediately before it reaches the surface (or ground) onto which is was dropped as the velocity and kinetic energy will increase due to freefall. For all objects that have some weight and are affected by air resistance (as air resistance increases as velocity increases), like skydivers, terminal velocity will occur when the force of the air resistance equals the force of gravity and acceleration will reduce to zero. At that point the body will fall at constant speed to the ground. That constant speed, by the way, may not be a slow speed and that is why there are parachutes for skydivers. Parachutes provide extra air resistance, and the skydiver will reach a new slower terminal velocity using the same reasoning as just mentioned.
Answer: It accelerates.
Gravity is a constant force, whereas wind resistance varies with the square of velocity. So at first the wind resistance is zero, and you accelerate due to gravity alone. After time T you have accelerated to speed S, and now there is some wind resistance and you are not accelerating as fast. Eventually the drag due to speed S is the same as the force of gravity, and presto, terminal.
When I skydived, the rule of thumb was that you reached terminal after about 12 seconds, at which point you were going 120 mph.
Mathematically, the force of gravity is Fg=mg, where m is the mass and g is acceleration of gravity in whatever units you prefer. Air drag is Fd = (CdA)(V2rho)/2, where Cd is a constant you look up based on the shape, A is the area and rho is the density of air. rho A and Cd are all constants, so it really comes down to V2/2.
You're at terminal when the force of gravity is the same as the force of drag, or  Fg = -Fc. Solving for V you get V = root(2mg/CdArho)
Rho for sea level is around 0.00238, and Cd is 1 for a sphere. So if you drop a sphere that's 1 square foot and weights 10 pounds, terminal is about 62 mph.
Comment: Worth mentioning that mathematically you approach, but never reach, terminal velocity.

Speed of a falling object


"Ask Question" interstitial notification doesn't show a "proceed" link on Firefox 3.6.13

Question: When I tried to post a question this morning on Stack Overflow using Firefox 3.6 on Mac OS X 10.6, I could not proceed to the actual form because the link never showed up. The only reason I can tell you guys right now is because I'm using Chrome.
Answer: I think I know what has caused this (although I couldn't reproduce it); if I'm correct this will be fixed in the next build.
Please let us know if you still see this tomorrow. Thanks!


How adapters can accept 110-240V but still outputs a constant current

Question: My monitor comes with an adapter , which accepts electricity from wall, ranging from 110V-240V. I am wondering how it could output a same amount of current despite a dynamic voltage?
Comment: They have in-built regulator.
Comment: 1) with the exception of LED drivers, power adapters output a constant **voltage**, not a constant current. 2) basically the adapter has an internal reference voltage, it compares the output voltage to that reference voltage, that generates an error signal which is used to control another part of the circuit to increase or decrease the voltage. To fully understand how this works some serious study into electronics is needed.
Answer: Isolated 220-110 to low voltage supplies are often switch-mode power supplies using a small transformer with a high frequency. If you change the duty cycle of the pwm controlling a power transistor you can change the output voltage. Most switch mode chips have an enable input. The reservoir capacitor on the output can serve as buffer to smooth out the enable and disable cycle.
With some measuring and feedback circuitry (using an opto-isolator to communicate back to the high voltage side) and you can then adjust that duty cycle to emit a constant voltage, a constant current,  a current-limited constant voltage or ...
Comment: On the adapter it states:
INPUT: 100-240V , 1A MAX
OUTPUT: 12V 3A
Comment: @Arkyo, read [Choosing power supply, how to get the voltage and current ratings?](https://electronics.stackexchange.com/q/34745/6334). The current rating is a maximum, not a fixed output value.
Answer: The maximum current would typically be limited by the components selected for the internal regulator circuitry, not by the input voltage or current (since a typical wall socket can supply around 1500 to 2000W, and I doubt your adapter is rated that high).  The actual current depends entirely on how much the device it's powering takes.
Answer: Typically they rectify to peak voltage AC to  DC then DC-DC converter to step down.
There will be  using a fixed reference diode voltage to regulate the output.


Should I use Mono on a real project?

Question: Has anyone used Mono, the open source .NET implementation on a large or medium sized project? I'm wondering if it's ready for real world, production environments. Is it stable, fast, compatible, ... enough to use? Does it take a lot of effort to port projects to the Mono runtime, or is it really, really compatible enough to just take of and run already written code for Microsoft's runtime?
Answer: I've used it for a number of internal and commercial projects with great success.  My warnings:

Write lots of unit tests and make sure they ALL pass under Mono -- this will save you a lot of trouble.
Unless you absolutely have to, do NOT use their embedding API.  It's damn easy to use, but it's ungodly easy to garbage collect valid memory or leak all of your memory.
Don't ever, ever, ever even come close to SVN and unless there's no choice, do not compile your own.  Things change so often in SVN that it's highly likely you'll end up implementing something that doesn't work on a release version if your project is significantly large.
Don't try and figure out problems on your own for long, use the IRC channel.  The people there are helpful and you'll save yourself days upon days -- don't make the same mistake I did.

Good luck!
Edit:  The reason I say not to compile your own from source (release or SVN) is that it's easy to configure it differently than release binaries and hide bugs, for instance in the garbage collection.
Edit 2:  Forgot to answer the second part to your question.  In my case, I had no issues with porting code, but I wasn't using any MS-specific libraries (WinForms, ASP.NET, etc).  If you're only using System.* stuff, you'll be fine;  beyond that, you may run into issues.  Mono 2.0 is quite solid, though.
Answer: I find Mono to be mostly binary compatible with MS. Hence I simply compile with MS, and run anywhere, like Java is meant to be!
The performance of Mono on Linux is getting very close to MS, as little as 2 times slower in some cases, vs 5-10 times slower when running Mono on Windows (but you should really stick to MS then).
Answer: I had some experience with Mono.
Pure .NET stuff (like business logic, controllers or algorithms) can be ported without any problems. Yet, weird things start showing up in the components that interact with operating system, UI, services or persistence. So be prepared for some debugging and hacking.
Things that might help:

Component-Driven Development - so that code is reused by Windows .NET and Mono, while differences are isolated and tested)
Continuous Integration running and checking everything against Mono and MS.NET, so that possible issues could be discovered as fast as possible (automated deployment and sanity checks are also recommended)
There are not a lot of UI component suites for shell development in Mono.
When a component vendor says that his code is "compatible with Mono", it is not same as "runs on Mono and is supported".

Although in the present, there are some companies going into production with Mono, I'd still wait before rushing in there due to:

Lack of decent and commercially supported UI component suites
Issues with efficient garbage collection
Not the best debugging experience (compare with the historical debugger in VS 2010)

PS: if there is a company offering fully managed cloud computing solution (not just a VM, but more like Hadoop equivalent for .NET), then I'll be forced to jump in despite these issues.
Answer: If you are doing ASP.NET 2.0 work, it works very well. Winforms may work, but it can cause display issues. If you want compatibility in a forms app, I would suggest GTK#, as it is crossplatform.
Like suggested, as long as you thouroughly test, I would agree to using it commercially if that is a viable option for you, unless it is winforms you need. In my opinion, i would stay away from it for now. And forget WPF as there is no support at this time, and there may never be (although they are working on moonlight, aka silverlight for linux)
Answer: I haven't used Mono myself but you may be interested to know that FogBugz uses Mono to provide Lucene.NET on Linux platforms.  (I only know this because Joel mentioned it in passing in Stack Overflow Podcast #24.)
Comment: Do you happen to have any links to further information on this? I am looking to port Lucene.Net to Mono.
Answer: I've got a bunch of shell apps in production.
I agree with @cody-brocious, write a lot of unit tests. I found in the past that Regular Expressions didn't work exactly the same way as the windows CLR.
It's actually simplier than you think to get into, just compile and run. If you use NAnt on your projects its even easier to transition.
I typically install mono from the source releases and I haven't had any problems.
Answer: I've used it for encryption/decryption tools and it worked fine.
In the future, I would consider using Mono/C#, but I would not expect it to be 100% exactly like .Net on Windows.
Comment: A detailed overview about what you think is missing would be helpful.
Comment: What I think is missing?  Official support from Redmond, for one.
Answer: Of course, you can, especially after Mono 2.0 has been released.
Mono 2.0, is ready for real projects.
You can check this

Should I use Mono on a real project?


Is TCP Port 80 (HTTP) vulnerable?

Question: I heard hackers' top ports to hack computers through are port 80 and port 443. How do they do this though aren't port 80 and port 443 just for HTTP requests such as GET, POST?
Answer: Any open port can be used as an attack vector by a hacker to get into the system. Port 80 and port 443 just happen to be the most common ports open on the servers. Now there are two different ways to get into the system through port 80/443:

Exploiting network behavior.
Exploiting application behavior. (If any application is listening over port 80/443)

Former includes vulnerabilities in the system stack (platform) itself that is responsible for accepting data through the port and passing it to the application.
Latter includes vulnerabilities in the application, i.e., when the data has already reached application through platform.
Most common attacks exploit vulnerability in website running on port 80/443 to get into system, HTTP protocol itself or HTTP application (apache, nginx etc.) vulnerability.
Comment: can you explain number 1 more I don't understand it.
Comment: No matter which port you connect on a server, the reference can always be compared with OSI model.
Layer 7 - Application.
Layer 6 - Presentation.
Layer 5 - Session.
Layer 4 - Transport.
Layer 3 - Network.
Layer 2 - Data Link.
Layer 1 - Physical.
HTTP operates at Layer 7 but the packet can only come from Layer 1 to Layer 7. My point is vulnerability can also be present in any of the other layers of this stack but Application layer.
Answer: No port is vulnerable. The software responding on those ports (web server) or the application you access from that service (web page) can be vulnerable.
Please take a look at the OSI model, which will help you with the concept of a "technology stack"
Answer: 80 HTTP, 443 HTTPs, they are used by web servers.
Can you hack something through port 80/443? It depends on the specific service that runs on those ports (which specific web server, i.e. nginx), and on the content which is provided by the web server. Usually it's latter which is vulnerable (sql injection, IDOR, look at OWASP top 10), even though also the web server can be configured wrongly.

Is TCP Port 80 (HTTP) vulnerable?


In which pH range are silica-based TLC plates stable?

Question: I am trying to understand why the experiment asks for raising the pH of a fairly acidic solution. The analytes should not be affected by it, so I thought the silica plate might be. Are silica-plates vulnerable in acidic conditions and, if yes, what happens?
Comment: I should add that the goal pH was between 6 and 7.
Comment: The pH value of an aqueous solution of $\ce{NH4Cl}$ is *mildly* acidic, and with an aqueous solution of $\ce{NaHCO3}$ you catch much of acidity, too.  If you prepare a long chain alcohol, for example, the quench with aqueous $\ce{NH4Cl}$ is meant to have no longer the alcoholate generated by the Grignard reaction, for example; simultaenously, to remove remains of salt ($\ce{MgBr2}).  In this perspective, the then extracted organic phase is *pure enough* to attempt the TLC, regardless if the pH of an aqueous solution in contact with the organic phase were 7.00 or *about* 6.
Comment: At the stage of monitoring the progress of the reaction, or to monitor the quench and (extractive) workup of the reaction, chromatography does not yet deal with purification; which may be done subsequently by column chromatography, or other means like distillation, recrystallisation.
Answer: Assuming "normal" TLC with silica as stationary phase, and a mix of ethyl acetate / hexane as eluent, charged compounds (i.e., salts) do not elute well; their adsorption is too tight to move forward.
Hence, if your reaction is performed under acidic conditions (sulfonation reaction, for example), drop a small sample of your reaction into a test tube or small vial, gently quench it against an aqeuous solution of $\ce{Na2CO3}$, extract it with some ether / MTBE / methylene chloride (well...) and spot the extract on the TLC plate.  With some training, this works easily around o.5 mL of total volume.
Conversely, if your reaction proceeds under basic conditions (like a Grignard reaction, for example), bring the sample back to neutral, for example with dilute HCl (or, with more fragile products like tertiary alcohols, with an aqueous solution of $\ce{NH4Cl}$), and then spot the organic extract on the plate.

I referred to "normal" TLC as there are other stationary phases than silica, too.  Alumina (basic, neutral, acidic) works with the same principle as silica.  These two contrast to applications of RP-TLC, were the stationary phase is coated with alkyl chains, and much more polar solvents are deployed as eluents, hence with much lesser issues of free salts / free acids. But the price tag for these plates is higher than for normal phase TLC.


What is the max number of devices (disks) that can be mounted?

Question: And obviously I am meaning practically - is it dozens, or hundreds?
Comment: Any particular OS?
Answer: On unix or Linux, individual device volumes are manifested through device files, traditionally held in the /dev directory.  Depending on the device driver architecture or disk controller hardware you may be constrained in the number of devices actually supported, but this is a hardware or device driver constraint rather than an O/S specific constraint.  The theoretical maximum is constrained by the number of bits available to the Major number, but will be 28, 216 or some other fairly large number.  Note that a disk could be partitioned and therefore have multiple volumes on it.  The space for device drivers is similarly large on Windows (note that Windows NT based systems support mount points so you aren't constrained by drive letters).
If you use hardware RAID or SAN based disks, a volume will be based on a group of disks presented by the controller, so the number of physical disks can be even larger.
In practice, the limitations of physical hardware is going to be a constraint before the number of available device handles becomes a problem.  This will be the case on most O/S platforms.
To take a more practical example, a typical SAS disk array such as an HP MSA70 has (IIRC) four SAS ports and internal port multipliers connecting multiple SAS disks to each port.  It will also allow a second array to be daisy chained off it.  These arrays hold 25 disks each, so a group of 4 SAS ports can support up to 50 disks in two shelves.
A typical SAS RAID controller has 8-24 ports, so a single controller could take up to 4-12 arrays, or 100-300 disks.  A large server such as an HP DL785 might be able to take several such controllers, so you could in theory put 1,000 or more disks on the machine.
However, this is probably not a very useful configuration.  Dedicated SAN or NAS hardware or parallel file systems are much more likely to be appropriate for storage requirements needing 1,000+ physical disks.  Database servers with 1,000+ direct attach disks are pretty rare outside of TPC-C benchmark configurations and the next few years will probably see SSDs taking over the market for storage on high-volume transaction processing applications.
Large SANs can scale to several thousand physical disks.  A single fibre channel loop can support up to 254 disks and a high-end SAN controller can support many F/C loop interfaces.  A logical volume manager can concatenate multiple physical volumes into a large file system, so a machine could potentially consolidate data from multiple SAN controllers into a single global volume.
The largest SAN I have seen documented had around 6,000 physical disks on it, but the limits are dependent on individual hardware.
Parallel file systems can scale outward by adding more nodes.  With hardware like a Sun X4500 (thumper) one could scale outward by adding servers until you run out of network ports.  The largest infiniband switches have several hundred ports, so a parallel file system based on Sun X4500s could support tens of thousands of physical disks.
However, any of thse large scale storage architectures will present RAID volumes spanning multiple physical disks to the host, so the number of logical units (devices) seen by the host will typically be much smaller.  In almost all cases the physical limits of the hardware will restrict the number of disks before the name space on the host is exhausted.
These configurations can all be purchased off-the-shelf (for a price) from specialist vendors without having to go to any sort of exotic proprietary supercomputer architecture, so the answer to your question is:

Thousands or tens of thousands at the top end (without needing custom hardware).  In fact, clustered file systems based on Sun X4500s or X4540s appear quite frequently as the storage components of Top 500 supercomputers.
Somewhere between 100 and perhaps 1,000-1,500 (at a guess - based on 4 28 port SAS RAID controllers with 2 shelves per 4 ports) on a Wintel or Lintel server.  Oviously this will vary depending on the specific hardware.
External arrays notwithstanding, a desktop PC will be limited by the number of drives you can fit in the case.  External desktop arrays might extend that limit to a few dozen, but this is niche market hardware.
Comment: The major/minor value is a 32bit number in Linux 2.6 kernels.  With 12 bits of that for the major value and 20 bits for the minor value.  2.4 kernels had a 16bit major/minor value with 8 bits for each portion.  The Major value is fixed based on the type of disk then each type has a way of assigning a minor value to each disk/partition.  So you can't use the whole 20bit range for drives.  But it's a big number.  see http://www.linuxdriver.co.il/ldd3/chp-3-sect-2.shtml and http://www.linux-tutorial.info/modules.php?name=MContent&pageid=94
Comment: Linux 2.6 looks like the limit is SCSI 65,536 devices, which include SATA and SAS.  These devices however can be made up of multiple drives if they are all RAID arrays or LUNs.  I think you would be hard pressed to max that out.  And if you did max it out it was due to poor planing.  Of course that may not be practical as the original question asks.
Answer: Well, in DOS, you're limited to the number of available drive letters (which can be expanded up to "Z").  So, that'd be 26...
Comment: Even in dos... a disc could be a RAID from a RAID controller, so a lot more than 26 discs ;) Sorry ;)
Comment: @TomTom: Sure, but you don't mount each of the individual discs separately.
Comment: @TomTom I take "devices (disks)" to mean addressable partitions/shares due to the context of "mounting", not count of the physical hard drives, not number of physical discs inside of each hard drive, etc.


How to know which direction the tangent of a point in an electric field points towards to determine the direction of electric field at that point?

Question: A tangent from a point can be extended in either direction at a time, so how do we determine the direction of electric field at that point?
Comment: Welcome to the site. It's quite difficult to answer this question as written without a diagram or some more precise words of explanation of exactly what you're asking, I can't really follow what you mean by "tangent from a point" here.
Answer: By convention, the direction of the electric field at any point is the direction of the force that a positive charge would experience if placed at that point.
Hope this helps.
Answer: According to Wikipedia:

A field line is a graphical visual aid for visualizing vector fields. It consists of a directed line which is tangent to the field vector at each point along its length.  A diagram showing a representative set of neighboring field lines is a common way of depicting a vector field in scientific and mathematical literature; this is called a field line diagram. They are used to show electric fields, magnetic fields, and gravitational fields among many other types. In fluid mechanics field lines showing the velocity field of a fluid flow are called streamlines.

In usual practice, only finite number of field lines are drawn.

The way to draw obeys some rules.  For example, the line density (therefore flux density) is proportional the field strength.

Illustration of Gauss' Law (2D or 3D): For a selected a closed contour (or surface in $3$D), number of outward lines minus the number of inward lines is proportional to the net charge enclosed.

Field line pattern gives a qualitative visualization only.  Only direction (with arrows shown or polarities known) of the vector field (but no magnitude) for an arbitray point on a selected field line is known.

For a point not on the field lines drawn, we need to guess the direction (usually more or less parallel to adjacent field lines) when the exact mathematical expression of the vector field is not known.

Alternatively, we can use CAS to plot vector fields on regular lattice points such as Wolfram Alpha:

See also mathematical treatment of electric field pattern in my post here.
Comment: You haven't told the OP what determines the direction of the arrow of the field line, which I think was the question
Comment: OP mentioned tangent, we can guess at least field line pattern is known.  But if only the field pattern is given **without** showing arrows and knowing the polarities of the singularities (sources and sinks), **both directions** are possible providing Gauss' law still held.  Plotting vector field is more concise though looks less elegant.
Comment: Yes, but I have never seen field lines without arrows, in which case, it begs the question as to what determines the direction of the arrows shown, which was the basis of my answer. But I would agree that it is not totally clear what the OP is asking for, thus the reason it has been closed.
Comment: Please feel free to see my previous [*post*](https://physics.stackexchange.com/questions/382905/electric-field-lines/383068#383068).  Due to software limitation, arrows were omitted.  Also, the dimension was squeezed to $2$ so that the force law became $\dfrac{1}{r}$ so as the Gauss' Law preserved.


VB Treeview causes vs32host.exe to stop working

Question: this program is a Windows Form app written in VB 2008
I have a datatable (dtSubFolders) through which I am iterating to populate a treeview(tv_Folder_Hierarchy) by sending its NodesCollection to a recursive subroutine.  The NodesCollection seems to be populating correctly as evidenced by the data at the bottom.  However, when I expand the root, I see its 7 children then I get a  vs32host.exe has stopped working error.
<code>   For Each row In dtSubFolders.Rows
        m_folder_Node = New TreeNode
        Get_TV_Node(tv_Folder_Hierarchy.Nodes, row(1).ToString)

        If Len(m_folder_Node.Name) > 0 Then
            m_folder_Node.Nodes.Add(row(0).ToString, row(2))
        Else
            tv_Folder_Hierarchy.Nodes.Add(row(0).ToString, row(2))
        End If
    Next

Private Sub Get_TV_Node(ByRef Nodes As TreeNodeCollection, ByVal Name As String)

    Dim node As TreeNode

    If Len(m_folder_Node.Name) = 0 Then
        For Each node In Nodes
            If node.Name = Name Then
                m_folder_Node = node
                Exit For
            Else
                If node.Nodes.Count > 0 Then Get_TV_Node(node.Nodes, Name)
            End If
        Next
    End If
End Sub
</code>

ID      Parent  Kids    Text
1811    None    7   Root Folder
1818    1811    40  Award Creation
1828    1818    0   Award Creation Sub 1
1819    1818    0   Award Creation Sub 2
1824    1818    0   Award Creation Sub 3
1839    1818    0   Award Creation Sub 4
Answer: PLICK - Problem Lay In (between the) Chair and the Keyboard.  In my rush I hadn't noticed bad untrapped code in the NodeMouseClick event.
BAH!


Why is 'for examples' wrong?

Question: If you want to take an example or several examples, you use the phrase 'for example,' not 'for examples.' Though the word 'example' is a countable noun, why is 'for examples' wrong?
Comment: In my view it's not necessarily wrong,  just not idiomatic.
Comment: Because you can only list one example at a time, perhaps chained to others with "and also consider" or some such.  If you are going to list Fred, John, and Frank as examples (not chained) you should say "... and consider the examples of Fred, John, and Frank ..." or some such.
Comment: You can certainly use *examples* as a plural, but "for example" is kind of a stock phrase.  In the sentence, "For example, A, or B, or C", you're still considering each of them as an individual example.
Comment: if you're going to give **plural** examples, examples include: "examples include A, B, C" or "with examples being A, B, C" or "some examples are A, B, C".  You hear those forms all the time - it's totally normal.  In contrast, if you are going to give **one** example, obviously you have to use a singular.
Comment: @brasshat hmm, what's an example of what you are thinking of?  A plural is a plural.  You can most certainly use "for examples" if you offer **plural examples**:  it's common to say "Blah blah, for examples, you need only look at A, B, C" or "Blah blah, for examples of that, you need only look at A, B, C."
Answer: When you say "for example" you're referring to the idea of "example".  The "for" isn't a way to shorten "To further illustrate my point here is a list of examples".  In this way "example" isn't countable.
Answer: You can use it, but even if used correctly, it will sound wrong to people, and will likely distract from the message you are trying to send.
For examples, see ngrams and search results here and here.
Answer: The Merriam-Webster Learner's Dictionary interprets the phrase "for example" as an idiom separate from the definitions of the individual word "example". See here. Interestingly, even though the dictionary defines "for example" as "used when you are mentioning a specific person or thing..." (emphasis added), it gives a plural case as an example:

A lot of my friends were there—John and Linda, for example.

At least by the Merriam-Webster Learner's Dictionary, both "for example" (as an idiom) and "for examples" (direct use of the countable noun) should be acceptable for your plural case.

Why is 'for examples' wrong?


Why do MySQL MyISAM table indexes go out of date?

Question: I have few MyISAM tables, where only the auto_increment primary key is up to date with the number of columns, but not other indexes.
Any idea, why this happens?
Answer: This is only a guess but here it goes...
The only way I know that a PRIMARY KEY for a MyISAM table would be OK and all secondary indexes be out-of-date would be under this unique circumstance:
Running this
ALTER TABLE mytable DISABLE KEYS;

and forgetting to undo it with
ALTER TABLE mytable ENABLE KEYS;

When you disable keys, the PRIMARY KEY and all UNIQUE keys are unaffected. When you enable keys, all secondary indexes get rebuilt.
According to MySQL Documentation on ALTER TABLE:

If you use ALTER TABLE on a MyISAM table, all nonunique indexes are created in a separate batch (as for REPAIR TABLE). This should make ALTER TABLE much faster when you have many indexes.
This feature can be activated explicitly for a MyISAM table. ALTER TABLE ... DISABLE KEYS tells MySQL to stop updating nonunique indexes. ALTER TABLE ... ENABLE KEYS then should be used to re-create missing indexes. MySQL does this with a special algorithm that is much faster than inserting keys one by one, so disabling keys before performing bulk insert operations should give a considerable speedup. Using ALTER TABLE ... DISABLE KEYS requires the INDEX privilege in addition to the privileges mentioned earlier.
While the nonunique indexes are disabled, they are ignored for statements such as SELECT and EXPLAIN that otherwise would use them.

SUGGESTION
First, make a copy of the table.
Try running
ALTER TABLE mytable ENABLE KEYS;

and see if it does anything. If not, run
REPAIR TABLE mytable;

Give it a Try !!!


Besides binary, decimal, hex, oct, are there encryption algorithms based on exotic/other numbering systems?

Question: We all know there is Base 10, Base 16, etc. Are there encryption algorithms out there based on different or unique Base-N numbering systems?
Comment: Note that different bases do nothing for security; FF1 and FF3 basically take a base 2 algorithm (computers work on bits) and convert it so it can be used on different input / output domains. FF1 and FF3 are handy if your input / output needs to be in a particular range - the algorithm itself of course still works using bit operations. You can also use e.g. base64 on the ciphertext if your output should adhere to a specific range of printable characters.
Answer: There's FF1 and FF3, which are Format Preserving Encryption methods that can use an arbitrary base internally.  This can be useful, for example, if you are encrypting a fixed length alphanumeric field, it would make sense to use base 36 (radix=36) or base 62 (if upper and lower cases are distinguished).


Wizardry before Harry Potter

Question: I'm writing a book about the hidden wizard world that spread and broke because of the fear of being shown up and it's the first book that starts the series, the adventure is about one guy lead the whole wizard world to get together and to establish a ministry and schools to develops the wizarding world. There's a villain as well. The start of the story and the villain is a bit similar to the start of the Harry Potter series and to Voldemort as well. But they are not the same. Just touch and go one. Any comments?
Comment: Are you planning to write about the wizarding world described in Harry Potter (if so, you can't, that would be plagiarism) or another world inspired by the series that differs in important aspects? Even in the second case, that sounds like a question you need to ask a lawyer.
Answer: There are plenty of bits and pieces of knowledge around concerning witches and wizards. If you are concerned about doing something similar to Harry Potter, maybe use other known aspects that aren't included in that series. Research can be fun.
Don't use terminology you can find all the time in Harry Potter (like "wizarding world"). Avoid big cliches you may find in there. Maybe have a different system/set of laws for magic.
Take your own originality and throw it in there to make it your own. If I've learned anything from reading and trying to write, it's that no matter what your idea is (even if you thought of it before you saw anything like it outside of your head), it's been done before in some form or another. You just take the ingredients we all use and combine them in your own way, with your own spice added to it.
Also, if your book is inspired by the Harry Potter series at all, that's super cool, but it could potentially be a recipe for similarity (maybe). I'm guilty of similar things. I've heard that exposing yourself to more reading material can get new ideas in your head. Push yourself outside your comfort zone and pick up on whole new concepts. Then you'll have more material to work with, and it won't be too similar to one book series.
Stay creative
Answer: I think it's a great idea! You should definitely go for it! Just make sure you don't use too much of the Harry Potter series, though it's okay to get inspiration from it! The book that I'm trying to write, I started because of inspiration from the "Harley Merlin" series, so it's okay to have inspiration! Make sure to put a GINORMOUS spin of you onto it, okay?
Be you forever!

Wizardry before Harry Potter


Can I tell Cortez I'm gay, but not date him?

Question: Basically, my ManShep is going after Kaidan.  I want to tell Cortez that "I'm waiting for the right man..." but that man isn't Steve.  Can I do that and then turn him down gently, or will it lock me into a romance with him/offend him if I show no interest?
Comment: This question is a bit odd... If you want any good answers you will need to clarify more.
Comment: When I'm speaking to him in Purgatory, and we're talking about relationships (or something, I don't remember).  I can answer "I'm waiting for the right man" or "I'm waiting for the right woman" -- I want to answer I'm waiting for the right man, (e.g. Kaidan), but I don't want him to be offended if I answer that way and then reject Cortez (as a romantic relationship)
Answer: I'm not particularly familiar with the scene you're in, but it sounds like you're getting really close to Steve's "lock in" point.  Based on your description of the scene and your options, I'm guessing that you haven't actually reached it but you're still not far from it.
The Mass Effect Wiki has this to say about locking in Steve Cortez as a romantic option.
From Mass Effect 3 Romance Mechanics, in the Romance article:

Example "locked-in" locations are:
  ...
  - Steve Cortez: Kissing him when dancing at Purgatory after convincing him to take some shore leave on the Citadel.

From Romance, in the Steve Cortez article:
(Emphasis mine)

 Eventually, Cortez will be in the Purgatory Bar. Shepard notes that Steve looks happier and Cortez replies that Shepard was right about the past being his, and that no moment should be taken for granted. When the Commander expresses doubt that a nightclub is to Cortez's taste, Steve explains that there was an energy and life in dancing, suggesting that the eye candy isn't too shabby for him either. Shepard wonders why Cortez isn't looking at him, though Cortez admits his interest and invites him to dance. While Cortez and Shepard dance, the Commander tells Cortez about his feelings, wanting to be more than friends. In reply, Cortez thought he felt there was something between them but was merely pessimistic about it. Shepard affirms that feeling and kisses Cortez.

Based on the flow of the article, and what you've said about the decision point you're on, I think you're probably still a few steps away from the commitment point.  My guess would be that you can safely give either response without being immediately locked in.
Still, it's always safest to have a recent save (or autosave) point just before these interactions.
Answer: I know this is late, but just in case someone else stumbles on this and wants a straight answer.
You can say okay to dancing with him without locking into the romance.
They dance a bit and talk, and he says something along the lines of "You're a good friend". Then you get 2 options - "You're a good friend, too" or "I want to be more than friends". That's where you lock in if you choose to.


What live tile template does the official calendar app use in WP8

Question: I am trying to use a live tile layout similar to the official Windows Phone 8 "Calendar" app for my app's live tile and I am also trying to update the lock screen notification. I was originally planning on using the Iconic tile template because it seems to be the most straightforward means to display text, but realized that it does not display any text unless the user uses the wide tile size. The other option seems to be flip tile, but I want the text to be displayed on the front of the tile, not on the flip side. I considered using the cycle tile template and generate the image to show for various tile sizes, but seems like I can't update the lock screen notification if I use that. Does anyone know how I can display text on a medium sized tile and also have the same text appear on the lock screen notification?
Answer: It does not use a publicly available tile template. You would have to recreate the template using an image, for example as in http://blog.anthonybaker.me/2013/05/wp8-tip-creating-live-tiles-with.html


Best Practice for Canine profile

Question: I work for a nonprofit that trains service dogs for Veteran's with PTSD and we just started using salesforce. I am the admin, and still learning as I go... I am struggling with the best practice to create a profile, or contact page for our canines. I need to include all of the vet records, where they are (foster or placed with veteran), a photo, etc. They will also have a relationship that will link them to their foster contact or Veteran, for tracking purposes. My question is, should I create a custom object or record type for the canines? Or a custom object with custom record types? I will need to pull reports, set notifications for shots due, etc. I don't want to lose functionality by over complicating it. We are running NPSP Enterprise. Thank you in advance!
Comment: FYI - The question of tracking animals has been discussed in the past on the Power of Us Hub, so be sure to search (using a variety of terms) in the search field at the top right.
Answer: (As an aside, you may find more nonprofit-oriented support resources, including discussion forums, through the Power of Us Hub. Salesforce Stack Exchange specializes in specific, at least somewhat engineering-focused questions, but there are NPSP people here as well. Additionally, Salesforce just released a number of NPSP-focused modules on Trailhead).
There's no single right answer to this question, and it sounds like you still have a lot of your data architecture wide open. You could certainly make this work in a number of different ways, but I'll make a couple of recommendations.
Odd as it may seem, I'm going to suggest making your canines a new Record Type on Contact. That'll allow you to use the built-in NPSP Relationship object to track relationships to your foster contacts and veteran placements, to reduce the amount of custom work you'll need to do.
You can use a page layout specific to the Canine Record Type to surface only fields relevant to those animals, while preventing them from being displayed on human contacts.
Vet records are really a separate question, but I could see potentially utilizing Activities to track these work items. The NPSP comes with some interesting functionality around donor engagement activity plans that you could potentially repurpose, or build out custom functionality for more automation. That might be another topic to discuss with other NPSP users at the Power of Us Hub.
Comment: Thank you David, I will direct my question over to the Power of Us Hub, the trailheads are helpful to a certain point -  I know how to do it, I just need help with 'best practice'. Thanks again!

Best Practice for Canine profile


My boss told people I am pregnant without my permission

Question: I work at a daycare, and because Fifth disease was going around, I had to disclose to my boss that I am very newly pregnant (Fifth disease can be dangerous in the early stages of pregnancy). This happened a few weeks ago, and since then I have also disclosed a few personal details - in confidence - about my first ultrasound and some spotting to my boss. I returned from a day off of work to find out that she has told a few of my co-workers not only that I am pregnant, but some of those personal details. She also very often asks me about it in front of people who don't know, making it very hard for me to conceal the information. I am feeling very betrayed and like I can't trust my boss. Is this breech of confidence something that can be disciplined if I bring it to HR or head office? Am I overreacting?
Comment: Why did you tell your boss about the spotting, and about your ultrasound? It sounds like you were socializing with her as opposed to formally disclosing only required information. If you boss thinks you were discussing personal details in a social context, she would naturally feel free to share these with other women in your social circle -- unless you explicitly say that the conversation is confidential and private. Did you do that?
Comment: What outcome do you want? Do you want your boss fired? Or are you happy if they stop discussing your personal information?
Comment: @Heather I'd really keep it to the bare minimum. "I have a medical appointment on day X, and depending how things go, I may not be able to make it in to the staff meeting." They have no need or right to know what will happen at the medical appointment.
Comment: I don't necessarily want my boss fired, but I would like there to be some sort of disciplinary action, and for her to stop discussing my personal information.
Comment: I very clearly pulled her aside into a private room to tell her the information about the ultrasound. My first ultrasound showed a sac and a yolk sac, but not a baby (either there is no baby there, or i was just too early to see). I told her this information because my follow-up ultrasound is scheduled on the same day as a staff meeting, and I wanted her to know that if I received bad news, I wouldn't be able to make it to the staff meeting. It was clearly confidential, since the pregnancy itself was still confidential.
Comment: Hi @Heather, where are you located? Local laws may affect what answers people give.
Answer: You are not overreacting.
This is unacceptable, especially when you're in the early stages.
Pregnancy is generally considered personal information, and as a general principle, employers should not be sharing personal information without your authorization. You don't need to tell them you don't want the information shared. This is the default position.
In addition, miscarriage is not uncommon in the early stages of pregnancy, which is why people like to keep such things private. It can be difficult to explain that the situation has changed. Some people are not aware of how common such things are.
With regards to a solution, you have to figure out what outcome you are looking for here.
Your first step is to talk to the boss and tell them how they should change their behaviour. In addition, you should stop sharing information with them that you don't need to. Don't give them information about ultrasounds etc. Keep it to what they need to know.
It's OK to feel betrayed, but they probably didn't go out of their way to betray you. They probably had no idea that their behaviour is unacceptable. We would like to think that people in leadership positions would know their obligations, but this is not always the case.
Answer: For the sake of this answer, I'll assume you made it clear you wanted the information kept confidential and your boss is knowingly spreading it without your approval or consent.
You're certainly not overreacting. Anything you tell your boss in confidence should be kept confidential unless there's a serious, business-related reason to disclose it. Her behavior was highly unprofessional and you have every right to be upset.  As far as seeking disciplinary action against her, it really depends on your company's policy and culture. I believe it's unlikely that HR would punish her in any meaningful way. The most you could hope to gain would be to get her to stop spreading this information without your permission but at this point, it sounds like it's already out in the open and it may not be possible to get the cat back in the bag.
I could certainly understand why you may not be able to continue working with this person and I think your best bet would be to find another job or request to transfer to a different manager/location.
Answer: It could be that your boss misunderstood the interaction. Maybe she thought you guys are friends and she wanted to spread the news. Thus far, it doesn't sound like she released the information to harm you.
Nex time, I think you should be clear. "Boss, I am in the early stages of pregnancy and I haven't told anyone in the office yet. I appreciate it if we can keep things between us for now. I'm only telling you this because of the disease that may affect me personally."
I do think you should call your boss to another meeting and this time go over you hope she can keep the news private and hope it doesn't spread.


Option to exclude files in pg_basebackup command Postgres

Question: When cloning a standby, how can I prevent pg_basebackup from copying postgresql.conf and pg_hba.conf from the master to /var/lib/pgsql/9.9/data directory?
Currently I am using this command
[root@xyz..]# pg_basebackup -h {master ipAddr} -D /var/lib/pgsql/9.6/data -U postgres -v -P

Answer: according to docs:

The backup will include all files in the data directory and
  tablespaces, including the configuration files and any additional
  files placed in the directory by third parties. But only regular files
  and directories are copied. Symbolic links (other than those used for
  tablespaces) and special device files are skipped.

So there is no such option. If you still want to force it, move config files away from data directory (and optionally ln them to data_dir)
Answer: This answer is for Postgres 14. pg_basebackup takes backup of the entire data directory. https://www.postgresql.org/docs/14/app-pgbasebackup.html states that the backup utility will skip all directory/file that are symbolic links. So, that could be a workaround to get only desired content into the tar ball.
I had faced similar situations where I wanted to exclude the content of multiple directories like pg_replslot,pg_dynshmem, pg_notify etc. I made the tar ball the usual way: pg_basebackup -D /backup/ -F t -P -v. After the tar ball was made, and before restoring it to another server, I updated the tar manually by excluding content of all the required directories.


Does the most recent version of Elementary OS support Wayland?

Question: Does the most recent version of Elementary OS support Wayland?
If so, does the most recent version of Elementary OS support 125% fractional scaling for a fully high-definition monitor?
Answer: Currently elementary OS does not support Wayland, and neither will the next release.
However, the developers are making efforts to prepare elementary OS for a transition to Wayland in the future. They talk about this some in the recent Platform Changes in elementary OS 6 blog post.
I don't have a source for this, but I remember reading about how they don't plan on adding support for fractional scaling for various reasons.
Answer: I really like Elementary OS, but I switched to Pop! OS recently due to easier Wayland support (for Waydroid...).  The Elementary OS blog does mention that "future" versions will be use Wayland, so I will look into it again in the future.
Also, instead of using Fractional Scaling, there is a perhaps better way, which is to change the virtual screen resolution using xrandr.  You can find out more about this by checking the post on the frame.work computer forums written by the Elementary OS developer.  This method might be slightly lower performance, but it should be much more compatible with older apps, etc.
https://community.frame.work/t/using-elementary-os-on-the-framework-laptop/4453
This should work on any device, not just the Framework laptop.


Meanwell SMPS voltage regulation, changing the Trimmer (LRS series)

Question: I needed a 19V-20V source so I ordered some 24V LRS series SMPSs but they offer 10% adjustability, the voltage range just below that is 15V, the adjustability is also the same there. So none of them is going to provide me with the desired voltage range.  I am wondering if there is an option to widen that range by changing the Pot or trimmer.
Unfortunately, I have neither the product nor the full datasheet (no circuit diagram there only block diagram) to check the amplification from the voltage divider.
I need a suggestion if changing the pot will affect the controller-IC / O.V.P  or void my warranty. I don't want to use any buck-boost converter as that might introduce more ripples, and yes some diodes could be added to benefit from the forward voltage drop but that's a crude solution I hope there is something better.
Comment: Changing not the potentiometer but another resistor in-series with it may work.
Answer: Although you will probably void your warranty, if you measure all the R values around the Pot and the tap voltage Vref, you can reduce the voltage by adding a feedback resistor approx 4x the one from 24V Then the regulator will reduce the output to match Vref.
2.5 1.5 1.25 1V are common Vref voltages.
simulated here. Press the switch and adjust R to see results.

it comes with a +/- 15% adjustment range trimpot according to the range in datasheet.

I have done this before on laptop chargers. It is a standard tuning method.
You can solder directly to the nodes Pot and Vout with short leads.
If you can modify it without a trace and remove it, if it fails for some other reason, you might get warranty service. (Assuming no foul modification or ESD damage). But technically CE, UL and OEM do not permit selling it modified. But DIY for your own use, you take the risk of failure to follow these simple instructions.
Comment: Excellent explanation. But as I stated, given the price of the LRS, one should really consider if getting another suitable PSU wouldn't be more economical.
Comment: @tobalt 19.5V is std for laptops but not 350W. And $22 is a good price / value https://www.ledcontrollercard.com/english/meanwell-lrs-350-24-12v350w-power-supply.html?gclid=Cj0KCQjw4cOEBhDMARIsAA3XDRg4JU_4S8iHlgb9eq2QlEkN9rd3XlqTYzt0tueq94JnZWktJbQYN8caAtIPEALw_wcB
Comment: Thank you for the detailed reply, appreciate your effort and time. I was thinking like so, but if I have to jump  a resistor in that place it could be troublesome, as all the dividers are SMD. And that region is nearly flush mounted. So I am thinking just to increase the pot value and test first. Will that cause any problems initially?
Comment: @tobalt  I have searched they have 24 and 15 nothing in between. And as my supplier enlisted with only 10% adjustability.
Comment: Find the correct nodes from pot to 24V and measure resistance then use a 1/4W leaded resistor then. Much easier. It can be a short distance easily reached. Measure R if possible or trial and error will lower voltage only but removing with power on may cause some overshoot
Comment: @tony you are asking to replace the pot with a fixed value one? I am still not getting whats the problem with a higher value pot? will the gain factor will change that much for the value increase?
Comment: @Neail Pls. read again. The solution is to add a shunt resistor on feedback R about 4x to the existing value.  Why change a pot and risk damaging the PTH's (vias) and make tuning more coarse at the same time, when you can easily tack on a 1/4W R  to shift the feedback ratio to Vref.
Comment: Sure, I got your point. I will update doing the same.
Answer: I would not recommend fiddling with the inner workings of budget AC-DC converters. There is not much to be gained and much to be lost.
Most laptop PSUs have ~19 V out of the box, so maybe their regulation is good enough for your purpose.
Otherwise, if you are concerned about ripple and noise: Maybe stick with the LRS and add an LDO after it. This depends on the current demand. Off-the-shelf parts exist for up to a few amps. If you need more you can design your own regulation with a beefy load transistor, controlled by opamp and Zener reference.
Comment: @Neail LRS is a budget PSU series from Meanwell without active PFC. Careful if you use such devices with more than 75 W (where e.g. EU demands PFC). Wall adapters with ~19 V are very common up to about 200 W for notebook chargers: https://www.digikey.de/products/de/power-supplies-external-internal-off-board/ac-dc-desktop-wall-adapters/130?k=&pkeyword=&sv=0&pv48=116509&pv48=113670&pv48=119717&pv48=117392&pv48=143803&sf=1&FV=-8%7C130&quantity=&ColumnSort=0&page=1&pageSize=25 If you need more power, look for the enclosed converters (such as LRS) and filter for 19-20 V.
Comment: It's not that hard to reduce the voltage.
Comment: Hi, thanks for the reply., Some high current diodes in parallel might save me the efforts with the voltage range without LDOs! Yes, surely it is an option to regulate the voltage actively, but I don't want to for this application. I don't know about LRS could you please inform me?
Comment: @Neail diodes are a crude way to get where you want. But be aware of the heat they dissipate. What Tony wrote is a much more elegant way. What I suggest is the safest way ;)
Comment: yes, I am aware, but the same would be done by the LDO heat deception I mean? correct me if I am wrong. and  What are the basic difference between these PSU and Laptop chargers without the PFC? and I am a bit confused you recommend LRS in place of LRS? and thanks for the Link
Comment: @Neail LDO will also dump the excess as heat, true, but they regulate better along the way. If ~0.5 V regulation accuracy is fine, then diodes will be fine. I think there are no big differences between LRS and laptop chargers, but the latter come with 19V models. The LRS series offers higher power models though. However if you want to use more than 75 W, additional PFC might be needed, as LRS (and chargers probably as well) do not integrate them. But I guess there are also PSUs available with ~19V output, several 100W and PFC.


How to tell an ideal of integer polynomial ring is principal?

Question: I understand that uni-variate polynomial rings with coefficients in a field only have principal ideals. For example, $\mathbb{C}[x]$. But how can I tell if an ideal of integer polynomial ring is principal, please? For example, a textbook claims that "the kernel of the map $\mathbb{Z[x]} \rightarrow \mathbb{Z[i]}$ sending $x \mapsto i$ is the principal ideal of $\mathbb{Z}[x]$ generated by $f=x^2+1$" without any justification. How to show this is true, please?
Answer: In this case, it is fairly easy. Since the polynomial $f$ is monic, you can write every $p \in \mathbb{Z}[x]$ as
$$p = q\cdot f + r$$
with $r \in \mathbb{Z}[x]$ of degree at most one. Since - easily verified - $f$ maps to $0$, the kernel of $\pi \colon g \mapsto g(i)$ surely contains the principal ideal $(f)$ generated by $f$, and to show that it contains nothing more, by the above it suffices to show that no polynomial of degree $\leqslant 1$ except the zero polynomial is mapped to $0$. But $a + bx \mapsto a + bi$, so $a+bx \in \ker \pi \iff a = b = 0$.
Comment: Thank you for your answers very much.
Answer: Since you know that $\mathbb{R}[x]$ is principal, you can use that.
Consider the extension of the map $x\mapsto i$ to $\mathbb{R}[x]$. The kernel of this map is clearly the principal ideal $I=(x^2+1)\mathbb{R}[x]$. Now consider $I\cap\mathbb Z[x]$, which is the kernel of the original map. If $g\in \mathbb R[x]$ and $g(x)(x^2+1)\in\mathbb{Z}[x]$, then by expanding the product it is easy to see that in fact $g\in \mathbb Z[x]$.
Comment: Thank you for your response.
Answer: A prime ideal in ${\bf Z}[x]$ can only be $(0)$, principal, or maximal.  Your ideal is not $(0)$ because it has an evident nonzero element.  It's not maximal because ${\bf Z}[i]$ does not contain a field.  That leaves one option.


What weapon is the best for a brawler

Question: In pathfinder there is a hybrid class called the brawler. It is part monk, part fighter. It can increase the damage of "close weapons" to the damage of an unarmed strike from a brawler 4 levels lower. What weapon would allow a brawler the greatest damage output? The main points being a weapon whose damage will be increased and has a good critical range.
Comment: Sorry, if that's the case, then you're just looking for the close weapon with the highest damage and highest crit range? Is there any reason the [Pathfinder Wiki](http://www.d20pfsrd.com/) hasn't/can't help you in this regard?
Answer: People far better with numbers then I have created the following formula to calculate average Damage per Attack.  Check out this Thread for more information regarding the formula.  Check out this AnyDice program for more information and calculations as well.
The damage formula is h(d+s)+tchd.
h = Chance to hit, expressed as a percentage
d = Damage per hit. Average damage is assumed.
s = Precision damage per hit (or other damage that isn't multiplied on a crit). Average damage is again assumed.
t = Chance to roll a critical threat, expressed as a percentage.
c = Critical hit bonus damage. x2 = 1, x3 = 2, x4 = 3.

Assuming you have a melee attack bonus of +11 after all modifiers have been applied, against an enemy with AC20, we can fill this out for your unarmed strike as follows
55%*(3.5+0)+(5%*1*55%*3.5)

Which equates to 1.925 damage per attack (Not including any strength bonus)
The Fighting Fan or Punching Dagger, both increase your critical multiplier to x3, which equate to an average DpA of 2.1175
The 19-20 ciritcal range of the Cestus gives the same result of 2.1175.
Your unarmed strike at 1d8 damage provides a result of 2.59875
The Scizore is a close weapon which deals 1d10 damage at the cost of 1 to your attack roll, and provides an average result of 2.8875 DpA
This result shows that while you are able to increase the damage of any weapon which does less then 1d6 damage, you are still better off using your unarmed strike, and better again with a weapon with a higher damage dice.
At level 5 with the brawler proficencies, I would suggest a Scziore as the best option for dealing the highest Damage per Attack possible.
Though a Close weapon with an 18-20 critical range, or an x4 critical multiplier does not exist, if one did for any reason, it would have an average DpA of 2.21375 as a comparison.
Answer:
Close Weapon Mastery
  At 5th level, a brawler's damage with close weapons increases. When wielding a close weapon, she uses the unarmed strike damage of a brawler 4 levels lower instead of the base damage for that weapon (for example, a 5th-level Medium brawler wielding a punching dagger deals 1d6 points of damage instead of the weapon's normal 1d4). If the weapon normally deals more damage than this, its damage is unchanged. This ability does not affect any other aspect of the weapon. The brawler can decide to use the weapon's base damage instead of her adjusted unarmed strike damage—this must be declared before the attack roll is made. (Source, emphasis mine)

The ability you're speaking of doesn't increase the damage of all close weapons. It instead brings those close weapons that deal damage lower than your unarmed strike (or, what it would be at your level - 4) up to that of your unarmed strike (Lvl - 4).
So the weapon that would grant your brawler a greater damage output would be any that deals damage greater than your unarmed strike at lvl - 4. Using the example in the rules text, this would be any weapon that with (a) damage di(c)e greater than 1d6. It's meant to make those weaker weapons more viable and not to increase the damage of weapons that already deal more than that.
Comment: Sorry, when I say do more damage than my unarmed strike I mean on average. A weapon with a 19-20 x2 crit range would be 5% more likely to crit than my fists. If there was a close weapon that had an 18-20 crit range in the close weapon group, it's base damage wouldn't matter because I would increase its damage to one damage die below my fists.

What weapon is the best for a brawler


Is it possible for a non Hindu who rejects the teaching of Vedas and Gita attain Moksha?

Question: Can a Muslim attain Moksha even if he worships Allah and follows the teaching of the Quran?
Can a Jew attain Moksha even if he follows the teaching of the Torah?
And can a non Sanatani attain Moksha and heaven?
Comment: Your answer is [here](https://hinduism.stackexchange.com/questions/44259/are-abrahamics-vaishnavas-according-to-sri-vaishnavism/44265#44265)
Comment: Your question is asking for opinions and is highly opinionated. 'Belief' does not constitute being religious. Religion is in being and becoming, not in belief. What you 'believe' is of minor consequence. All scriptures teach love of God, compassion for living beings, and unselfishness. If you practice these you are taking refuge in God, you will attain God. See Gita Chapter 9 verse.32, and GIta Chapter 18.
Comment: @Mr. Sigma But it doesn't answer my question
Comment: Moksha means freedom from rebirth, but Muslims and Jews dont believe in reincarnation of soul, but only on attaining heaven or hell on the judgement day, so the answer is no, unless they believe in immortal soul which is eastern spirituality, just like there is no God or religion for animal souls. "That Atman (self, soul) is indeed Brahman. It [Ātman] is also identified with the intellect, the Manas (mind), and the vital breath, with the eyes and ears, with earth, water, air, and ākāśa (sky), with fire and with what is other than fire, with desire and the absence of desire,"
Comment: " with anger and the absence of anger, with righteousness and unrighteousness, with everything — it is identified, as is well known, with this (what is perceived) and with that (what is inferred). As it [Ātman] does and acts, so it becomes: by doing good it becomes good, and by doing evil it becomes evil. It becomes virtuous through good acts, and vicious through evil acts. Others, however, say, "The self is identified with desire alone. What it desires, so it resolves; what it resolves, so is its deed; and what deed it does, so it reaps." — Brihadaranyaka Upanishad 4.4.5
Answer: Indeed even a non Hindu can attain Moksha. Swami Harshananda in one of his introductory essays writes "The statement of Sri Ramakrishna that there are several ice-bergs in the boundless ocean clinches this issue very well. All the ice-bergs as also the ocean itself, are all WATER only! Once this Vedantic background is grasped, the idea of polytheism vanishes completely. The worship of Siva, Sakti or Visnu becomes the adoration of the one Supreme Being who is Personal-Impersonal. The Bhagavad Gita (4.11; 7.21) states the same truth in an unmistakable language."

BG 4.11: In whatever way people surrender unto me, I reciprocate with
them accordingly. Everyone follows my path, knowingly or unknowingly,
O son of Pritha.

Swami Tapasyananda writes "According to the stages of human evolution, there will be different conceptions of the Deity, and the followers of one, even if they think theirs is more refined, need not look down upon others as heathens or Kaffirs worshiping false Deities, and consider themselves alone as the followers of the true Deity. For whatever the path, God approaches man through that path, and if the faith of the votary is genuine, he will be led to higher and higher forms of worship. So the followers of every religion must have respect for, and have acceptance of, the faith and form of worship of other religions in spite of the differences that are sure to prevailing their ideologies and practices. For it is the same God that is worshipped by them all. Just as all rivers, in spite of their divergent courses, lead to the same ocean, so do all faiths lead to Him, i.e., take one to the same God who inspires them all. This Gita teaching has been proclaimed to the modern world by Sri Ramakrishna in his saying: "As many faiths, so many paths

BG 7.21 : Whatsoever form any devotee desires to worship with faith
that (same) faith of his I make firm and unflinching.
BG 9.23 : Even those who, being devoted to other deities and endowed
with faith, worship (them), they also, O son of Kunti, worship Me
alone (though) following the wrong method.
BG 9.25 : The worshippers of other gods go to them; to the manes go the
ancestor-worshippers; to the deities who preside over the elements go
their worshippers; but My devotees come to Me.
BG 12.4 : Having restrained all the senses, even-minded everywhere,
intent on the welfare of all beings verily they also come unto Me.

All Vedic and Non Vedic Shastras and many more Sastras, the Omniscient Divine Being has made in brief.The wise say that each of these sastras is intended for a particular class according to the individual qualification, not all for one.  As all streams ultimately empty themselves into the ocean, so all these paths ultimately lead to the Mahesvara Himself. Worshipped in what form so ever by people as ordained in their respective scriptures. He assumes that form and takes the devotee on to the next higher step, By His Grace man attains to superior paths. Thus these paths, laid out as they are by Shiva, are all of them true and serviceable. Shiva is supremely merciful, omniscient, and altogether stainless. Yet of all the paths, the  path  of  the  Veda  is  the  best as  conducing  to  all  good." (Chapter 22, Yajna Vaibhava Khanda, Suta Samhita, Skanda Purana )
As the different streams having their sources in different places all mingle their water in the sea, so, O Lord, the different paths which men take through different tendencies, various though they appear, crooked or straight, all lead to Thee."(Shiva-Mahimna-Stotra compiled by Pushpadanta)
He who is called Krishna is also called Siva, and bears the name of the Primal Energy, Jesus, and Allah as well--the same Rama with a thousand names. A lake has several ghats. At one the Hindus take water in pitchers and call it 'jal'; at another the Mussalmans take water in leather bags and call 'pani'. At a third the Christians call it 'water'. Can we imagine that it is not 'jal' but only 'pani' or 'water'? How ridiculous! The substance is One under different names, and everyone is seeking the same substance; only climate, temperament, and name create differences. Let each man follow his own path. If he sincerely and ardently wishes to know God, peace be unto him! He will surely realize Him.(Gospel of Sri Ramakrishna)
You must remember that humanity travels not from error to truth, but from truth to truth; it may be, if you like it better, from lower truth to higher truth, but never from error to truth. Suppose you start from here and travel towards the sun in a straight line. From here the sun looks only small in size. Suppose you go forwards a million miles, the sun will be much bigger. At every stage the sun will become bigger and bigger. Suppose twenty thousand photographs had been taken of the same sun, from different standpoints; these twenty thousand photographs will certainly differ from one another. But can you deny that each is a photograph of the same sun? So all forms of religion, high or low, are just different stages towards that eternal state of light, which is God Himself. Some embody a lower view, some a higher, and that is all the difference.(The Complete Works of Swami Vivekananda Vol 4)
Answer: I cannot answer the questions about Muslims and Jews. But I can answer your last question.

And can a non Sanatani attain Moksha and heaven.

Yes, one does not need to believe in Hindu God or eternal Atman for attaining moksha. This conclusion is implied from some of the Gita verses below

2.14. But the contacts of the organs with the objects are the producers of cold and heat, happiness and sorrow. They have a beginning and an end, (and) are transient. Bear them, O descendant of Bharata.

2.15 O (Arjuna, who are) foremost among men, verily, the person whom these do not torment, the wise man to whom sorrow and happhiness are the same he is fit for Immortality.

In the above 2 verses, nothing is mentioned about God in the context of attaining moksha. Not coincidentally, this chapter of BG is called sAmkhya yoga and sAmkhya was originally non-theistic.
Krishna is also not very particular about belief in an eternal Atman. See below -

2.26 On the other hand, if you think this One (Atman) is born continually or dies constantly, even then, O mighty-armed one, you ought not to grieve thus.

2.27 For death of anyone born is certain, and of the dead (re-) birth is a certainly. Therefore you ought not to grieve over an inevitable fact.

Above verses show that according to Krishna, the removal of grief is more important than belief in Atman. Just by accepting the transient nature of things and maintaining equanimity in pleasure and pain, one can attain moksha.
Thus, it is not necessary to believe in God or eternal Atman for moksha.  A non-Hindu can attain happiness and moksha simply by following above teachings.


What are some examples of laser-based additive manufacturing techniques?

Question: I'm trying to research additive (or 'bottom-up') fabrication techniques that rely on lasers or other advanced photonic systems. So far, the most prevalent technique I've come across is two-photon polymerisation, but I'm struggling to find any others. Any further examples would be much appreciated.
Comment: selective laser melting, selective laser sintering and laser deposition welding with powder and/or wire come to mind
Comment: @OpticalResonator, please put your comment as answer
Answer: Here is an incomplete list of laser-based additive manufacturing, based on my comment. I might expand on it later:

Selective laser melting/sintering (SLM/SLS): a laser beam melts/sinters a layer of powder at the desired spots, after solidification, a new layer is added and the process starts over.

Stereolitography: basically the same as SLM, but instead of powder, you use a resin that solidifies when exposed to light. One of the oldest additive manufacturing processes.

Laser deposition welding: a laser melts a spot on a base plate, additional material is fed into this melt pool in form of powder or wire (processes with both at once also exist, need to search a bit for a citation). From there on you build up a part in layers. This process is very close to the classic "3D printer" with plastic FDM.


What do I if i got a bad nether fortress and cant find nether wart

Question: I was playing minecraft and got lucky that my portal was near the fortress but I got the one lava chamber with no indoor loot areas and i looked north and south for the other nether fortress but I could find any. I need help finding nether warts because I'm trying to start making potions for zombie villagers I looked for the piglin chamber and still havent found any nether warts. I'm getting so desperate to find this stuff that I copied my world went on creative and still have fould a single nether wart. Any thing I can do to get nether other than those two?
Comment: There are more then one fortresses, you will just have to find them.
Answer: Find another Nether fortress, nothing to it. Even without the Nether wart chamber not all is lost - some chests in Nether Fortress contain nether wart too. Also, if you find a bastion, some of them have nether wart in the 'treasure chamber'.
But in essence, keep exploring. Barter with piglins to get some potions of fire resistance, ender pearls, soul speed boots, and have patience - you only need a little of nether wart to start a farm of your own, so even if you find it very far, that's not a trip you have to repeat.
Answer: Some might consider it cheating, but you could make a copy of your level (or make a new level with the same seed) allowing cheats within the copy. Go into the nether in creative mode and use the /locate command to find a different nether fortress. Note the coordinates. Then load your non-cheat world and head for those coordinates.


New french drain not flowing

Question: 2 years ago I installed a perimeter drain on the wet side of my house.  It daylights at the road and works great.  Last week, I installed an additional 30' leg.  The new leg is inboard of the existing drain and runs parallel between it and the house.  Construction is identical to the old drain: good pitch, lined w/ non-woven cloth, perf (holes on the bottom), #2 stone over top, then wrapped like a burrito and secured w/ landscape staples.  It wasn't practical to daylight this leg at the road so it terminates into a catch basin.  The basin connects to the existing drain. There have been several significant rains since install and no water flows.  Zero.  I'm stumped; it should be working.  It's worth noting that the soil spread on top was wet so it is compacted.  Water isn't infiltrating as well as I'd like, but the soil layer also isn't very deep.
Comment: Does the original drain have crushed rock up to the surface? Why did you place a new drain inboard of the first one? Was water standing between the first drain and the foundation?
Comment: Jim, yes; there was standing water between the existing drain and the foundation.  It is not an "open" french drain--meaning the stone does not come to the surface.  A shallow layer of (wet) topsoil was placed over the #2.  (Shallow = ~3".)
Comment: To clarify, the new drain is not open (it's covered w/ topsoil.)  The existing drain is open--#2 finishes the drain at grade.
Comment: Presumably there is a swale parallel to these two drains and parallel to the foundation. Where is it located relative to the foundation and to these two drains?
Answer: On many soils, rain will only penetrate an inch or so.
So if you have a good layer of soil then you have effectively waterproofed your drain.
I put one in using a trench alongside a gravel path and as it had the same stones no one knew - worked well though.
Answer: Assuming everything is built correctly, water is simply not rising to the level of this drain. Possibly because the level is adequately controlled by flowing sideways into the existing drain, or it's otherwise happy to keep flowing down below the drain level (or across the surface) rather than accumulating and flowing into this pipe.

New french drain not flowing


What is SNLF technology?

Question: Aerion together with Lockheed Martin is building the AS2 supersonic jet. This is the most realistic SS business jet project of all time. But what do they mean by SNLF technology which claims to reduce drag? And how is it better than the delta wing which they claim is inferior.
Comment: It does not say what it is. It's just a 2 page press release :/
Comment: "*This is the most realistic SS biz jet project of all Time*". What is SS? Supersonic?
Answer: SNLF stands for Supersonic Natural Laminar Flow.
Laminar flow over the wing reduces the friction drag. Achieving this has been the aim of a number of designs, from the laminar flow airfoils of the past to the latest 737 MAX winglet. While it is difficult enough to achieve in subsonic flight, the high wing sweep and Reynolds number in supersonic aircraft make it much more difficult to achieve.
One method of achieving this is to use wings with low sweep (unlike delta wings) and sharp (supersonic leading edges) at the expense of other forms of drag.

Dark colors show the expected laminar flow regions, while the graph shows the pressure gradients. Image from Unconventional Configurations for Effecient Supersonic Flight by I. Kroo
A number of designs have been proposed to this end from reverse delta to the Aerion's design, which looks strikingly similar to F-104 starfighter.
One method of achieving the laminar flow (i.e. extending it chordwise) in supersonic flight is by using laminar flow control (LFC) methods like suction etc. A good example is the use of suction in a F16XL test aircraft by NASA, which produced laminar flow over nearly half of the wing (less than the design value though).

F16XL with porous titanium LFC glove on the left wing, image from NASA report TF-2004-12 DFRC, F-16XL Supersonic Laminar Flow
The problem with LFC is that it increases weight and takes up space in the wing, hardly an advantage in a supersonic aircraft. So, the next thing to do is increase the laminar flow distribution without using any mechanical (or other) aids.
Natural laminar flow means the presence of laminar flow even in the absence of any LFC measures. From NASA F-16XL Supersonic Laminar Flow document:

Passive laminar flow can be achieved in the wing design process, .... Passive laminar flow can also be created on an existing wing by altering the cross-sectional contour of the lifting surface to change the pressure gradient. Both of these laminar conditions are called natural laminar flow.

SNLF then, is basically laminar flow in supersonic flight without the aid of active boundary layer control methods.
SNLF has been demonstrated in the past (unsurprisingly in F-104), but the tools to analyze it and replicate it in other aircraft were lacking. This seems to the main thrust of the Aerion.
The AS2's wing design has been tested by NASA in a F-15 and the results seem to be encouraging.

SLF flight test on F-15 with NASA Dryden (top). Predicted transition (left)
and infrared image (right) showing extensive natural laminar flow. Mach 1.8, 40,000 ft., Reynolds Number about 10 million. Image from Unconventional Configurations for Effecient Supersonic Flight by I. Kroo
Aerion doesn't say that delta wing is inferior, but it is a simple fact that you can't use a delta wing for supersonic laminar flow. Aerion claims that its design will have 20% less drag than delta wing, but till the aircraft actually flies, we should take its announcements with a large dose of salt.
There are other problems the company has to overcome if the product is to be successful- if the wing is thin (as I expect it to be) and quite small, the aircraft's range appears wildly optimistic. For example, the F-104 had thin wings, but had the fuselage to put the fuel in; something that is very difficult in AS2 unless the passengers agree to carry some. Also, the small wing size may lead to quite high landing speeds.

Planform comparison of AS2 (top) and F-104. Not to scale. AS2 from company website; F-104 from Wikipedia- attributed to Kaboldy.
Comment: Maybe it can carry fuel in the fuselaege. Passenger cabin doesn't take half the length from what I see in the pictures. It's 52m in length while the concorde was 62m and could carrry 100 passengers.
Comment: It's not just small wing, but also the profile. The leading edge has low sweep, so it must be sharp for supersonic flight, but sharp leading edge means low stall angle of attack, which further increases the landing speed. For a fighter (F-104) they could have said if slats fail, the pilot will eject. But a passenger plane must be able to land with flap+slat failure…

What is SNLF technology?


I am trying to Import a CSV file into SQL Server 2008

Question:
Error 0xc02020a1: Data Flow Task 1: Data conversion failed. The data conversion for column "Solution" returned status value 4 and status text "Text was truncated or one or more characters had no match in the target code page.".
Error 0xc020902a: Data Flow Task 1: The "output column "Solution" (90)" failed because truncation occurred, and the truncation row disposition on "output column "Solution" (90)" specifies failure on truncation. A truncation error occurred on the specified object of the specified component.
Error 0xc0202092: Data Flow Task 1: An error occurred while processing file "C:\Users\siddhary\Desktop\Created interactions1.csv" on data row 2.
Error 0xc0047038: Data Flow Task 1: SSIS Error Code DTS_E_PRIMEOUTPUTFAILED.  The PrimeOutput method on component "Source - Created interactions1_csv" (1) returned error code 0xC0202092.  The component returned a failure code when the pipeline engine called PrimeOutput(). The meaning of the failure code is defined by the component, but the error is fatal and the pipeline stopped executing.  There may be error messages posted before this with more information about the failure.

Please can any one help me....
The column called solution has data consisting of text & special characters, I have specified that column as NVARCHAR(MAX).....
Answer: 1st thing Id check is-  Open up your flat file connection manager, select the column that's being imported and see what the data type is set to -

Check the Output Column width and increase if its small


Caffe and Tensorflow on a Dell 7559 with nvidia optimus technology

Question: I bought a dell 7559 laptop for deep learning. I got ubuntu 16.04 installed on it but I am having trouble getting caffe and tensorflow on it. The laptop used Nvidia Optimus technology to switch between gpu and cpu to save battery usage. I checked the bios to see if I can set it to use only gpu but there is no option for it. Using bumblebee or nvidia-prime didnt work either. I now have ubuntu 16 with mate desktop environment it is preventing from getting the black screen but didnt help with the cuda issue. I was able to install the drivers and cuda but when I build caffe and tensorflow they fail saying that it didnt detect a gpu. And I wasnt able to install opengl. I tried using several versions of nvidia drivers but it didnt help. Any help would be great. thanks.
Answer: I think Bumblebee can enable you to run Caffe/Tensorflow in GPU mode. More generally, it also allows you to run other CUDA programs on a laptop with Optimus technology .
When you have installed Bumblebee correctly (tutorial: Bumblebee Wiki for Ubuntu ), you can invoke the Caffe binary by pepending optirun before the caffe binary. So it goes like the following:
optirun ../../caffe-master/build/tools/caffe train --solver=solver.prototxt

This works for the NVidia DIGITS server as well:
optirun ./digits-devserver

In addition, Bumblebee also works on my dual-graphics desktop PC (Intel HD 4600 + GTX 750 Ti) as well. The display on my PC is driven by the Intel HD 4600 through the HDMI port on the motherboard. The NVidia GTX 750 Ti is only used for CUDA programs.
In fact, for my desktop PC, the "nvidia-prime" (it's actually invoked through the command line program prime-select) is used to choose the GPU that drives the desktop. I have the integrated GPU connect to the display with the HDMI port and the NVidia GPU through a DisplayPort. Currently, the DisplayPort is inactive. The display signal comes from the HDMI port.
As far as I understand, PRIME does so by modifying /etc/X11/Xorg.conf to make either the Intel integrated GPU or the NVidia GPU the current display adapter available to X. I think the PRIME settings only makes sense when both GPUs are connected to some display, which means there need not be an Optimus link between the two GPUs like in a laptop (or, for a laptop with a Mux such as Dell Precision M4600, the Optimus is disabled in BIOS).
More information about the Display Mux and Optimus may be found here: Using the NVIDIA Driver with Optimus Laptops
Hope this helps!


Reference request for a treatment of Schwinger–Dyson equations

Question: Is there a treatment of Schwinger–Dyson equations with no mention of Green's functions? Is there perhaps a purely algebraic analog?
Answer: I will differ somewhat with the answers by Carlo and Zurab. Just because the identity now known as the Schwinger-Dyson equation was first discovered in the context of Green functions, does not mean that it is most naturally expressed in terms of Green functions (aka QFT correlation functions).
Let me refer to the excellent treatment of the Schwinger-Dyson equation in Chater 15 of Quantization of Gauge Systems by Henneaux & Teitelboim (PUP, 1994). Consider functionals $A[\phi]$ on the space of (off-shell) field configurations $\phi$. Let us suppose that all of these functionals are sufficiently regular so that we can use the variation formula $A[\phi + t\zeta] = A[\phi] + t \int \alpha_i[\phi](x) \zeta^i(x)\, dx + O(t^2)$, for some $\alpha_i[\phi](x)$ which we also denote by $\frac{\delta A[\phi]}{\delta \phi^i(x)}$. One of these functionals is the action functional $S[\phi]$ and its variation $E_i[\phi](x) = \frac{\delta S[\phi]}{\delta \phi^i(x)}$ gives the classical equations of motion of the field theory.
For any given off-shell functional, there is a map $A[\phi] \mapsto T(A[\phi])$ which stands for the time ordered quantization of $A[\phi]$, so that $T(A[\phi])$ is an element of the quantum algebra of (on-shell) observables (or operators). The map $T$ is linear, but obviously not an algebraic homomorphism because it maps a classical (commutative) algebra into a (quantum) non-commutative one. Also, since it maps (classical) off-shell functionals to (quantum) on-shell operators, it must have a kernel that is somehow generated by the equations of motion.
The Schwinger-Dyson equation precisely specifies the kernel of $T$ within the space of classical off-shell functionals:
  $$ T\left(A[\phi] \int \lambda^i(x) \frac{\delta S[\phi]}{\delta \phi^i(x)}\, dx + \frac{\hbar}{i} \int \frac{\delta A[\phi]}{\delta \phi^i(x)} \lambda^i(x)\, dx \right) = 0 , $$
for any $A[\phi]$ and $\lambda^i(x)$, where $\lambda^i$ needs to be $\phi$-independent. Note that the treatment in Henneaux & Teitelboim uses equations like $\langle T(-) \rangle = 0$ instead of $T(-) = 0$. However, they use $\langle \hat{O} \rangle$ to stand for an arbitrary matrix element of the operator $\hat{O}$ (evaluated using a path integral), so the two kinds of equalities are equivalent. As can be seen from the above formula, the kernel of $T$ is an $\hbar$-deformation of the subspace of off-shell functionals generated by $\int \lambda^i(x) E_i[\phi](x)\, dx$ for arbitrary $\lambda^i(x)$, which all vanish when restricted on-shell, to the solutions of $E_i[\phi](x) = 0$ among all possible field configurations. To get the full classical kernel of the restriction on-shell, we would need to allow $\lambda^i(x) = \lambda^i[\phi](x)$ to be $\phi$-dependent. But doing that naively breaks the above formula. So, when possible, arbitrary $\lambda^i[\phi](x)$ should be approximated by linear combinations of appropriate choices of $A[\phi]$ and $\lambda^i(x)$.
One final remark about a more geometric way of rewriting the above version of the Schwinger-Dyson equation. Let us interpret $\lambda^i(x)$ as a vector field on the field configuration space and denote the corresponding Lie derivative by $\mathcal{L}_\lambda$. The Schwinger-Dyson equation then reads
  $$ T\left( \frac{\hbar}{i} e^{-iS[\phi]/\hbar} \mathcal{L}_\lambda ( A[\phi] e^{iS[\phi]/\hbar} ) \right) = 0. $$
Answer: A quick and clear and rigorous derivation of the Schwinger-Dyson equation from BV-theory in causal perturbation theory is offered in remark 7.7 of Rejzner 16, it's spelled out at nLab:BV-operator -- Schwinger-Dyson equation.
The upshot is the the SD-equation is nothing but the incarnation of the free field theory quantum BV-differential, schematically of the form $\{S,-\}_{BV} + i \hbar \Delta_{BV}$; hence the quantum correction in the SD-equation originates in the BV-operator $\Delta_{BV}$.
In the traditional path-integral heuristics this is highlighted already in section 15.5.3 of Henneaux-Teitelboim 92 (which Igor Khavkine is pointing to in his reply), where therefore it is suggested to call the free quantum BV-differential the "Schwinger-Dyson operator".
Answer: I'm not sure why you would want to avoid Green's functions, which provide the most natural formulation of the Schwinger-Dyson equations, but indeed, algebraic approaches do exist. In the context of random Riemann surfaces the Schwinger-Dyson equations appear as a set of algebraic constraints on the partition function, and they can be given a geometric interpretation. See for example Section III of The Schwinger Dyson equations and the algebra of constraints of random tensor models at all orders.
Answer: In the formulation of QFT using formal functional integrals, as mentioned by Igor in his answer, the Schwinger-Dyson equation becomes an infinite-dimensional differential equation for the partition function. As such, since the partition function is the generating functional for the Green functions, all you are doing is simply grouping the Schwinger-Dyson equations for all Green functions together in a single formula. I also share Igor's viewpoint that the Schwinger-Dyson equations written in terms of the partition function is more natural, because it makes the structure of the equation much more evident.
That being said, there are two nice references that have not been mentioned by the answers given so far. One is the book Path Integral Methods in Quantum Field Theory by R. J. Rivers (Cambridge University Press, 1987), where the Schwinger-Dyson equations are a central concept and are formulated in many different ways. Another, which I strongly recommend, is the paper by M. Dütsch and K. Fredenhagen The Master Ward Identity and Generalized Schwinger-Dyson Equation in Classical Field Theory, Commun. Math. Phys. 243 (2003) 275-314, arXiv:hep-th/0211242. In this second reference, it is shown that the Schwinger-Dyson equation is actually a particular case of the quantum correction (due to perturbative renormalization) to all identities that follow from the classical equations of motion, called the Master Ward Identity (MWI for short). The quantum BV-equation mentioned in Urs's answer is also a particular case of the MWI, which has a nice algebraic interpretation - to wit, one can see the classical limit of the MWI as the simple fact that the (left-hand sides of) all identities that follow from the classical equations of motion are elements of the ideal of off-shell functionals of field configurations (satisfying certain conditions which we do not need to recall here) which is generated by the Euler-Lagrange operator. At the quantum level, not all identities survive due to renormalization - the ensuing violations are known as anomalies. This means that the "classical" ideal of formal power series in $\hbar$ of functionals generated by the Euler-Lagrange operator is no longer an ideal with respect to the quantum product. However, the most general form for the anomalies is dictated precisely by the MWI. In the case of local gauge (or BRS) symmetries, this leads through the quantum BV equation to the Wess-Zumino consistency conditions and so on.
Just a final word of warning: it must be said that all of the above can be made rigorous only at the formal perturbative level. In constructive QFT, the Schwinger-Dyson equations are usually not used as a tool to construct a model but are rather derived rigorously as a consequence after the model has been constructed, since only then can they be made sense of. Analysis of QFT models using the Schwinger-Dyson equations is usually deemed as "non-perturbative" for the equations make no explicit mention of perturbation theory, but making sense of this equations outside perturbation theory is a messy business.
Answer: In addition to Carlo Beenakker's answer, in the context of the theory of random matrices the Schwinger-Dyson equations are discussed (without any mention of Green's functions) in the book http://link.springer.com/book/10.1007%2F978-3-540-69897-5 (Large Random Matrices: Lectures on Macroscopic Asymptotics, by Alice Guionnet). See also http://arxiv.org/abs/1307.1806 (Schwinger-Dyson equations: classical and quantum, by James A. Mingo and Roland Speicher).
However, I agree to Carlo Beenakker that the most natural language for Schwinger-Dyson equations in quantum field theory is the language of Green's functions. Even when the Schwinger-Dyson equations are discussed in the very abstract mathematical context, it is useful to use the analogy with Green's functions to get an insight of what is going on. See, for example,  http://arxiv.org/abs/hep-th/0404090 (The residues of quantum field theory - numbers we should know, by Dirk Kreimer) and http://arxiv.org/abs/hep-th/0407016 (What is the trouble with Dyson--Schwinger equations? by the same author).
Comment: Thanks for the responses, especially Igor's since H&T is by my side right now and is in the context that provoked the question. quoting `` it is useful to use the analogy with Green's functions to get an insight of what is going on'' applies only if one has some feeling for Green's functions


Looking for the name of Philsopher or Philosophy/Book/Thesis from around Enlightnement period about human inclicnation to tribalism

Question: Im not sure what im looking for exactly but having read it in the past from "history of philosophy" (coppleston type series of books) where it was discussing a type of philosopher or philosophy that argued that even if you removed religion that man would be inclined towards "tribal" type of mentality ie mankind cant escape religion he is naturally inclined towards it would break down into tribes or groups based on some belief about society or nature or standards ie sexuality/environment/epithets/epoch
Answer: Well, what you have is rather ambiguous, however, we can start you on the path by noting that the idea that humans have a nature that is demonstrable and exists independent and before modern forms of social organization is called the state of nature. From WP:

In Ethics and political philosophy, in social contract theory, religion, and international law, the term state of nature describes the hypothetical way of life that existed before people organised themselves into societies. Philosophers of the state of nature theory propose that there was a historical period before societies existed, and seek answers to the questions: What was life like before civil society?, How did government emerge from such a primitive start?, and What are the hypothetical reasons for entering a state of society by establishing a nation-state?

Now, of the philosophers in the WP article, perhaps the most famous for taking a pessimistic view of humans is Hobbes in his Leviathan which is a very prominent example of a metaphor in political philosophy called the social contract. Along with Locke and Rousseau, Hobbes essentially discussed an extended metaphor of how modern society is governed by an implicit agreement between a person and society. The Leviathan contains a famous Hobbes quotation:

No arts; no letters; no society; and which is worst of all, continual fear, and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short.
Comment: sorry if you misunderstood me but what i was asking is which philosopher describes how man is tribal and even if we remove religion people will gather around and break off into echelons of society around some difference of opinion , like that south park episode where its "science vs science" when religion is removed
Comment: that is political philosophy ,nothing to do with nature of man
Comment: Man is a political animal. The idea that political philosophy and the nature of humans its not related is an absurd statement.