Not Able to View Objects with Barlow Lens

Question: I am new to using a telescope and am having a hard time using a Barlow lens. I was able to find Jupiter multiple times using a 6mm lens with a telescope that has a D = 60mm and FL = 700mm. I am very close to seeing some detail (making out some color/features) but it is still a little too blurry. Whenever I equip the Barlow lens (x2) the object is nowhere to be seen (even when focusing and moving around). Any tips to using a Barlow? Is 6mm too small to use with a Barlow?
Comment: Not an answer, but while the Barlow will increase your magnification, it won't make the image any less blurry.  At 700/6 = 117x magnification you may have reached the limit for your telescope and local observing conditions. Further increases are probably going to be what's called "empty magnification". There are some good questions and answers here in this site about the limits of useful magnification. [Astronomical seeing](https://en.wikipedia.org/wiki/Astronomical_seeing) is mostly what you are up against. It can vary a lot from night to night and gets better later into the night.
Comment: Or another approach: Use the Barlow and a longer eyepiece, e.g. 15 mm, to find Jupiter. Once you have it lined up, carefully swap eyepieces. But as @uhoh pointed out, the telescope you have is unlikely to give clearer images at that magnification - just bigger. I found this clears things up nicely:  https://supercooper.jimdofree.com/magnification-guide/ . Quoting: "Generally you will find that you will use magnifications in the region of 50x - 150x most of the time regardless of the size of your telescope!"
Comment: It's much more difficult to find objects with high magnification. Have you tried finding the object with a low power eyepiece then changing to the Barlow, being careful not to move the scope.
Answer: There are some rules of thumb when it comes to telescopes and usable magnification.
One is that your maximum usable magnification is two times the diameter of your telescope's aperture in millimetres (or 50 times the diameter in inches).
Another is that the best views will be provided by an eyepiece which has a focal length (in millimetres) equal to the focal ratio of your telescope.
(This one is basically saying "Use an eyepiece which gives an exit pupil of 1mm")
NOTE, however, that these are guidelines and not hard rules. Depending on the seeing where you live and the quality of the optics of your telescope and eyepiece, you can go above these 'limits'.
Think of them as hints to help people avoid spending money on eyepieces that they'll rarely be able to use :-)

Let's take your 60mm / 700mm telescope:
According to the first rule, 60 x 2 = 120x magnification is your theoretical maximum, and your 6mm eyepiece gives about that.
On good nights with exceptional seeing, you might be able to push the magnification higher, but probably not very often.
And the second, 700 / 60 = 11.6mm.
An eyepiece of this focal length will give an exit pupil of 1mm. An eyepiece of, say, 12mm in your telescope will show you all the detail you'll be able to discern. Going lower than this will give you a larger image, which can be useful, but you won't see any more detail. Most of the time you'll only just increase the amount of blur.

To answer your questions: "Any tips to using a Barlow? Is 6mm too small to use with a Barlow?"
Use a Barlow to give you focal lengths which you don't already have in an eyepiece.
Use a Barlow for those rare nights of good seeing, to push the magnification as high as possible.
Yes, 6mm + a 2x Barlow in your telescope results in too low a focal length and too high a magnification for all but the rarest occasions.
Eyepieces with focal lengths that low are for fast F-ratios - around F/4 and below - where they'll give usable exit pupils (and maybe usable magnification, too, given good seeing)
In your telescope, the 6mm eyepiece gives an exit pupil of half a millimetre and probably the highest magnification you'll ever be able to use.
Comment: Thank you for the detailed response. It really had me to understand the topic and telescopes :). Right now I have a 6 and a 25 with a x2 Barlow. So that means that with the Barlow I technically have a 12.5 and a 3mm as well. The 3mm being too small and that is the issue I am facing. :) Would 9mm with a Barlow still be usable? Since it is 4.5 and pushing the maximum? I really appreciate you posting an answer!
Comment: It's early where I am and I'm pre-coffee so "nobody is clear" to me yet :-) Thanks for the link! I'll take a look now.
Comment: @uhoh ooh nice one! I'd like to try and have a go at answering that after work today :-) (btw your link there is to your meta question, but it's only one more click after that to get to the main question)
Comment: You're welcome, @Luke , and I'm glad you found it useful. You could get an eyepiece that's between 8mm - 10mm, and then use your Barlow with it on a good night to get 4mm - 5mm. The problem, though, is going to be the exit pupil. The exit pupil is the beam of light which comes out of your eyepiece. As magnification increases the width of the exit pupil decreases, and when it gets below 0.5mm it gets difficult: the image is very dim, and it's hard to keep your eye positioned right. I wrote [another answer](https://astronomy.stackexchange.com/a/38898/28758) about it which you might find useful.
Comment: 700 mm / 60 mm is not 11.6 mm. mm/mm is unitless. Also, where does "An eyepiece of this focal length will give an exit pupil of 1 mm" come from? I don't understand the optics of that at all, and currently don't believe that the exit pupil defines how clear Jupiter will look. Please add a supporting link to an explanation. *Thanks!*
Comment: @uhoh maybe I wasn't clear? I said "an eyepiece which has a focal length (in millimetres) equal to the focal ratio of your telescope". OP's telescope's focal ratio is the focal length divided by the aperture: 700mm/60mm = f-ratio of 11.6, therefore an eyepiece of 11.6mm. Regarding the calculation: [divide the eyepiece focal length in millimeters by the telescope's focal ratio](https://skyandtelescope.org/observing/stargazers-corner/simple-formulas-for-the-telescope-owner/) - therefore to get an exit pupil of 1mm you want an eyepiece of the same focal length as the focal ratio.
Comment: Thanks! I'll fix that: fyi I've just asked [How does eyepiece exit pupil diameter affect image clarity and viewing experience?](https://astronomy.stackexchange.com/q/46969/7982)


What is Truth's view of the philosopher's stone?

Question: What is Truth's view of the philosopher's stone? In an episode Father mentioned that "playing god" was a sin in Truth's eyes. Why doesn't Truth punish alchemists merely for creating or using a philosopher's stone then?
Answer: This question does not have a straightforward answer: the only normal alchemist we ever see making philosopher's stones is Dr. Marcoh, and it does not look like he has ever actually seen Truth, based on the Q&A "Wasn't Dr Marco a sacrifice?". It is also doubtful whether or not the alchemist who created the artificial humans towards the end of the series ever saw the Gate; if he did, the homunculi would have had an additional candidate for the fifth sacrifice, but they only mention alchemists that the readers or viewers have already met at that point, none of whom would have seen the Gate. Similarly, Shou Tucker's experimentation on his wife and daughter surely should count as a form of human transmutation, but his body appears to be intact.
My guess would be that "playing God" is mostly at stake in attempted resurrections of the dead because the alchemist there is trying to reverse death, which is meant to be impossible. (Some posters in this Reddit thread on Shou Tucker argue similarly.) Those other transmutations that one might consider to be "playing God" might be morally suspect (much much more so than trying to resurrect a loved one), but they do not transgress the boundaries of life and death and attempt to reverse the natural flow from life to death in quite the same way.
Comment: didn't Dr Marcoh only ever make fake Philosopher's Stones which have questionable stability like Cornello's ring. even Cornello is wary of using his ring to bring back of doing anything too extreme with it (like bring back the dead)
Comment: @Memor-X: He clearly has knowledge of how the stones are made and IIRC there are flashbacks where he is sacrificing the people of Ishval, so I'd err on the side of believing that he made "real" ones.
Comment: Are there even "real" philosopher's stones in FMA? As far as I remember, anything that contains a soul (including Ed, any other human and any red stone that has been created out of sacrificed souls) can be considered a philosopher's stone. In neither anime, there was a stone that was perfect and undepletable. It's just a question of how many souls you pump into it.
Comment: @hajef: No, not in that sense, at least as far as I can tell. The closest thing is the "imperfect" stones that consume human souls. Ed and Al give up on the philosopher's stone route after learning how it's made, implying that they don't see an alternative, and their issue with it is more that it requires the use of human lives to begin with, not necessarily that it's undepletable.


Future of OpenCL?

Question: The OpenCL programming paradigm promises to be a royalty free opens standard for heterogenous computing. Should we invest our time in developing software based on OpenCL? Pros/cons?
Comment: In CUDA you can code harder. You have C++ classes, where OpenCL only supports structs. So CUDA is a little bit more mature. If you don't need the advanced stuff, then I would switch to OpenCL.
Answer: The question is too broad and vague to be really be answered. However, I do see one notable point against OpenCL, from the point of view of scientific computing, which is rarely emphasized. So far, there has been no effort to produce open source, infrastructure libraries for OpenCL, whereas CUDA has several excellent options:

CUBLAS, CUFFT, CUSPARSE
Thrust, Cusp, OpenCurrent
PETSc support

I believe this will really hurt OpenCL since a major facilitator of adoption is high quality, open libraries.
Comment: Libraries are born and die fast; standards live long and painful.
Comment: There is [ViennaCL](http://viennacl.sourceforge.net/), which is not to be overlooked.
Comment: @mbq Scientific libraries have long lifetimes and a large influence on thinking as well as practice. Witness CHARMM, BLAS, RELAP, GEANT, etc.
Comment: Interesting point; especially since the license to the CUDA compiler itself is not very open at all (which I assume these guys build on top of), whereas (as far as I can make out from the license) nothing would stand in the way of an ambitious programmer who wants to develop a fully open source OpenCL solution...
Comment: @JackPoulson I am also mystified by the lack of OpenCL libraries, but the CUDA reason is clear. They have really put resources behind hiring great people and developing useful libraries.
Comment: @MattKnepley: The only large project that I know of that uses OpenCL is Octopus, a DFT package. They announced their reasoning a while back as wanting to avoid CUDA since it is proprietary. If/when I look into adding robust GPU support into my packages, I will start with OpenCL for the same reason.
Comment: CUDA is a little bit more mature. You can use C++ classes for example. Sometimes the same thing is more difficult to be achieved in OpenCL than in CUDA. It's no surprise. CUDA is just optimized for their vendor's graphics card and were afaik first. OpenCL also supports normal processors and accelerators.
Answer: OpenCL vs what?
If the question is OpenCL vs CUDA, I see a lot of hand-wringing over this question, and it seems crazy to me.  It doesn't matter.   Honest.   The kernels - where all the hard thinking has to go - are practically identical between the two languages; you could write macros for your favourite editor to do 99% of the work to bounce between OpenCL and CUDA.   It has to be that way; they're low-level control of ultimately pretty similar sorts of hardware.    Once you've figured out how to write your important kernels in {OpenCL,CUDA}, it's trivial to port them to {CUDA,OpenCL}.
The boilerplate host code you have to write is similar, too, but CUDA keeps simple cases simple.   That's why we teach CUDA in our centre; you can leap straight into writing kernel code, whereas we'd have to spend 1-2 hours of our daylong course just explaining the kernel launching stuff for OpenCL.
But even there the difference isn't that important; once you start doing more complicated thing (asynchronous kernels on multiple gpus), they're both equally complicated and again you can pretty much do a line-by-line translation from one to the other.
If it's OpenCL vs the directive-based approaches -- OpenACC or HMPP or something -- those are probably (hopefully?) going to be good ways of programming these kinds of architectures in the future, where you can get 90% of the performance for 10% of the work.   But which choice will "win" remains to be seen and I wouldn't recommend spending a lot of time working with those just yet.
So I'd say, between CUDA or OpenCL pick a language that's convenient for you and use it, and don't worry too much about it.   The valuable part - figuring out how to decompose your problem into massively-parallel SIMD code for small cores with very little memory - is going to be pretty easily portable between programming models.
If you're using NVIDIA hardware - and you probably are - then I typically recommend CUDA - Matt Knepley's point about the libraries is dead-on.   If you're not, then OpenCL.
Comment: You say that the only difference is the kernels, and that the kernels are the same, but then say that you use CUDA because the boilerplate is simpler.  I happen to agree that the boilerplate in CUDA is simpler, but there are libraries that can help with OpenCL boilerplate, eg http://code.google.com/p/clutil/ and https://github.com/hughperkins/OpenCLHelper (disclaimer: OpenCLHelper is my own)
Answer: Whether you should invest your time in developing software based on OpenCL is a question only you can answer. If it looks like it has the potential to solve the problems you are facing right now, and no other open solution does, your best course of action is probably to take a risk on implementing a small project with it.
If that goes well, you can try it with larger projects and so on until you either build up enough confidence to standardise on it, or discard it in favour of some other solution (which might be your own proprietary solution, another open solution or even another proprietary solution).
The wonderful thing about the open source movement is that because you have the source you have everything you need to fork the project if necessary. Even if the community itself doesn't give you the facilities you need, there's nothing stopping you implementing those facilities yourselves. Also, if you wanted those facilities, there is a distinct possibility that other users might want them, so would appreciate it if you contributed those changes back to the core project.
Not only that, but if you make it better from your perspective, it might make it better for others, encourage them to submit their own enhancements and ultimately make the software better for everyone.
Finally, yes this is a rather generic answer to rather a generic question. To answer more fully, we need to know what your concerns over OpenCL are. Is it maturity? Community support? Ease of use? Time needed to learn? Time to develop? Changing your procedures? When you ask about the Pros and Cons, which other products are you attempting to compare OpenCL to? What research have you already done? What features do you need to support your heterogeneous computing environment?
Answer: One big PRO is the number of vendors behind OpenCL. I have some anecdotal experience about this, having met a research group that spent a large amount of time and effort to develop a fairly complicated CUDA code for an NVIDIA powered system. A year later after the code was developed, the research group got access to a larger and faster AMD based system but they could not use it as they did not have the (human) resources to port the code.
Even if the core set of features of CUDA and OpenCL are almost identical (as @JonathanDursi well pointed out), if the original developer is not the one assigned with the task of converting the code, the whole porting project can be quite time consuming.
However, there are some official incompatibilities between CUDA and OpenCL. Most remarkably CUDA support c++ templates while OpenCL does not yet officially support them. However, there is an effort made by AMD to develop an extension to OpenCL with support for templates and other C++ features, more information in this post from AMD dev central. I hope a future revision of OpenCL might add this work.
At this point in time (early 2012), the awesome libraries that @MattKnepley links to are closed source or use templates, so they will not become available for hardware other than NVIDIA, at least in the mean time.
For someone that is learning gpu-computing, I would say that OpenCL C can be quite difficult, as there are a lot of details that distract the learner from the basic ideas, whereas CUDA is simpler and straight forward. However, there are tools that make OpenCL much more simple to learn and use like PyOpenCL (the python wrapper for opencl) which brings all the python sugar to OpenCL (note that there is also a PyCUDA). For instance, the PyOpenCL demo for adding two arrays is just under 25 lines and it includes: creation of the arrays on host and device, the data transfers, the creation of the context and queue, the kernel, how to build and execute the kernel, getting the results from the GPU and comparing them against numpy (see links below).
PyOpenCL -- http://mathema.tician.de/software/pyopencl
PyCUDA -- http://mathema.tician.de/software/pycuda
For experienced gpu-programers, here I agree with @JonathanDursi, CUDA and OpenCL are fundamentally the same and there are really no mayor differences. Moreover, the hard work of developing an efficient algorithm for GPUs is very much language independent, and the OpenCL support from vendors and the documentation is now much more mature than say 2 years ago. The only point that still makes a difference, is that NVIDIA is really doing some great work with their support to the CUDA community.
OpenCL has the added benefit that it can run on CPUs and is already supported by Intel and AMD. So you don't need to change your algorithmic framework if you want to take advantage of any available CPU cores. It is not my opinion that OpenCL is the best solution for a single CPU / multicore oriented application as a CPU optimized kernel might look significantly different than a GPU optimized kernel. However, in my experience CODE development does benefit from being able to run on the CPU.
Answer: I think OpenCL is currently suffering from a lack of a "champion". For example, if you visit the NVIDIA site right now (12/16/2011), you've got several "Ken Burns Effect" style shots on the splash page focusing on the scientific/industrial side of GPU computing, and ~1/4th of your navigation options point you toward things that will probably end up at CUDA. Manufacturers selling "GPU computing" servers and workstations are selling NVIDIA solutions.
Competing offers from ATI are mixed in with the general AMD site, harder to find, and not as heavily featured in third-party solutions. Those solutions, and the ability to do OpenCL based programming certainly exist, but it's left a perception - at least in my mind, but in the minds of some other folks I've talked to - that the OpenCL platform's big corporate sponsors have already "quit the field". People using OS X for example, are all probably too busy speculating about whether or not a Apple workstation will even exist in a year to have faith in them pushing OpenCL GPU computing.
Answer: The most important factor is that CUDA will remain supported only by NVIDIA hardware.
Thus, if you want to make robust and portable software, OpenCL is the only option. At most you can build around some currently CUDA-powered libraries and hope they will get extended over OpenCL in future pulling your code with it.
Comment: In fact, it will likely be the opposite. OpenCL will end up adopting all the nice things from CUDA (most of which are already there, where do you think it came from?) and getting rid of the more objectionable stuff in there right now.
Comment: Not at all clear. There are certainly proprietary standards which became open after many people adopted them.
Comment: @MattKnepley Please, even NVIDA is not trying to force CUDA as a standard; not to mention that even if they would, they will end up with something basically identical to OpenCL.

Future of OpenCL?


How to connect relay

Question:
How to I connect the pins of one channel relay to control and led which is connected to pin 13 of an arduino uno.can you tell me the steps which pin will go to which pin
Comment: Unclear.  Do you mean to use the Arduino pin 13 LED signal to drive the relay?  Or some other LED to be controlled by the relay?
Comment: You need no relay to control a LED.  Merely a resistor to limit the current.  See the 220 ohm resistor in series with the LED in the tutorial at https://www.arduino.cc/en/Tutorial/Blink -- they insert a LED in pin 13 in series with a resistor to Ground.
Comment: I insert an LED on pin 13 ....so I want to control that
Comment: Are you asking which are the outputs and which are the inputs of the relay board?  Look at the bottom of the board and compare it to the datasheet of the relay: http://www.langir.com/pdf/pcb-relay-T73.pdf
Comment: But in my relay I don't have any sign like normal connection,command connection and all so I want to know which one is what
Comment: I modified my answer a bit -- you can look up the datasheet of the relay and follow the traces on the circuit board.  Us folks on the internet can't do that without better pics/diagrams.  Please be careful attaching your circuit to AC line currents.
Answer: Wiring Diagram to Pin 13 for a single relay? This might help.
Answer: I believe that the Arduino ground should be common with the 12v source ground. I may be wrong, though that's the way it works for me. Also be aware that some of these relay cards work when the pin is LOW, others when the pin is HIGH. Mine energises when the pin is HIGH, though all tutorials I had read until the last had the relay switching on with a LOW pin.
Comment: This relay has "Normally Open (NO)" and "Normally Closed (NC)" outputs. Applying voltage would "invert" these.
Answer: It looks like http://www.elesof.com/electronics/product/one_6v_spdt_relay_board  , http://shop.ciseco.co.uk/jqc-3f-t73-5v-pcb-relay/ and it probably works like http://www.electronics-tutorials.ws/blog/relay-switch-circuit.html
I'd bet that the I/P line connects to the center pin on the transistor through one of those resistors.    If so,  I'd put a 5V 100mA source on the GND +5 pins on the side, then I'd use a jumper from the +5 on the end to the I/P on the end, and see if it triggers the relay as expected.
If so, I'd siconnect the jumper and I'd connect the end terminal's GND to the arduino GND, and (maybe?) pin 13 to the I/P line and expect the Blink tutorial that blinks the Arduino's LED to click the relay in time.
If you are asking which are the outputs and which are the inputs of the relay board, I can't tell from the pictures. Look at the bottom of the board and compare it to the datasheet of the relay: http://langir.com/pdf/pcb-relay-T73.pdf  --

I'd bet that screw terminals are the outputs, connecting to the right hand pair of outputs, and the center of the left hand three inputs.   And that the  control terminals are the pin connectors, with the I/P conneting through the transistor to one end of the coil, with the other end of the coil going to the +5V/12V pin connector.  There are likely two sets of pin connectors to provide for a separate coil/relay supply on the GND,5V12V connector versus a signal or signal plus power on the GND,I/P,5V/12V pin connector.  I'd bet the same-named pin connectors are electrically identical.  i.e. GND=GND and 5V/12V=5V/12V.
If you are controlling other than low voltage devices with this, I suggest you make certain you are safe before applying potentially dangerous currents.
Comment: Common is always in the center, facing the terminals NO will be on the left in most cases and NC on the right.
Comment: Of course I don't need a relay for led but if I want to control an AC bulb..and can you tell me which one is command,normal connection of relay on that image

How to connect relay


How are transactions collected into new block?

Question: How are the latest transactions collected into new block to send them to miners for hashing? Which part of the network is responsible for giving miners the correct block to hash?
Answer: The mempool as it is called, stores transactions that are propagated by the peer to peer network.  Miners have the ability to select which transactions they include in the block.  It is beneficial for the miners to collect as many transactions as possible so they can obtain the most amount of fees that they can.
Answer: If you are running a node, you can call the getblocktemplate API and you'll actually see all the transactions within the mempool.
This site shows the mempool transactions. You then get your code to typically sort from highest fees to lowest fees, run other checks such as is it within the MAX_BLOCK_SIZE and then create a block header that is to be hashed.
Which part of the network is responsible for giving miners the correct block to hash?
That would be your network. You create the block header and send it somewhere to start the hashing process. That somewhere could be your laptop, it could be a dedicated miner connected to your laptop or it could be a dedicated miner connected to a raspberry pi that is connected to your home/local network.


Impossible to install ubuntu 12.10 both with wubi or regularly

Question: I've tried installing Ubuntu 12.10 both with Wubi and from live CD (USB actually), neither of which was successful.
With Wubi, installing it inside Windows, it gives a black screen after the first reboot.
Sometimes it writes:
"Completing the Ubuntu installation. For more installation boot options, press ESC now... 10...9...8... 0"
and than it freezes again. I also tried pressing ESC and, choosing any of the options, it still freezes.
I've searched on the internet and people say to use nomodeset after pressing F6, but I never get to the screen where I can press F6. So I added nomodeset by hand after quiet splash inside the file wubildr-disk.cfg (I also tried to take away the quiet splash without any sucessful result).
I also tried with the regular installation as a dual-boot.
I can copy Ubuntu live CD onto USB key with Unetbootin and when I do the boot from the USB key, it freezes after Unetbootin asks whether to install Ubuntu/try Ubuntu/check for errors on the CD/etc.
Here, I've also tried out the nomodeset trick in the boot file but it failed.
I think the problem is connected with the Nvidia card but I don't now how to solve it.
I have an Acer Aspire 5750G, Intel Core i3, Nvidia GT520m, Windows 7
PS: My first choice would be to install Ubuntu inside Windows (I already had it this way but it blew up when I did the upgrade to 12.04).
Answer: Try setting graphics mode to Integrated in BIOS. I also had the same problem and was able to install Ubuntu by changing this setting. However, Ubuntu does not boot when I change the setting back to original value (I think it was Switchable)


cherrypy fails to stop when puppet tries to ensure running and refresh it at the same time

Question: I am trying to manage a cherrypy service with puppet. However, when the configuration is applied, cherryd ends up with no PID file although the process is up and running. Since the PID file is lost I can no longer stop the process with /etc/init.d/mycherryd stop (unless I modify the handmade init script to lookup the PID with ps or something.)
$ /etc/init.d/mycherryd status
cherryd dead but subsys locked

The problem seems to be that puppet is trying to refresh/restart cherryd (triggered by changes in configuration files) immediately after ensuring it's running (as specified in the manifest), and cherrypy fails to stop and start (restart) itself while still executing its startup process.
Is there a clear cut solution to this problem? Is this a bug on the cherrypy side, or can I write a puppet manifest so refresh is called only after the service is up and running? Any suggestion welcome.
cherrypy log
See how cherrypy catches SIGTERM midway through startup and still starts to listen.
:cherrypy.error[18666] 2010-02-12 13:10:23,551 INFO: ENGINE Listening for SIGHUP.
:cherrypy.error[18666] 2010-02-12 13:10:23,552 INFO: ENGINE Listening for SIGTERM.
:cherrypy.error[18666] 2010-02-12 13:10:23,552 INFO: ENGINE Listening for SIGUSR1.
:cherrypy.error[18666] 2010-02-12 13:10:23,552 INFO: ENGINE Bus STARTING
:cherrypy.error[18671] 2010-02-12 13:10:23,554 INFO: ENGINE Daemonized to PID: 18671
:cherrypy.error[18671] 2010-02-12 13:10:23,554 INFO: ENGINE PID 18671 written to '/var/mycherryd/cherry.pid'.
:cherrypy.error[18671] 2010-02-12 13:10:23,555 INFO: ENGINE Started monitor thread '_TimeoutMonitor'.
:cherrypy.error[18670] 2010-02-12 13:10:23,556 INFO: ENGINE Forking twice.
:cherrypy.error[18666] 2010-02-12 13:10:23,557 INFO: ENGINE Forking once.

:cherrypy.error[18671] 2010-02-12 13:10:23,716 INFO: ENGINE Caught signal SIGTERM.
:cherrypy.error[18671] 2010-02-12 13:10:23,716 INFO: ENGINE Bus STOPPING
:cherrypy.error[18671] 2010-02-12 13:10:23,716 INFO: ENGINE HTTP Server cherrypy._cpwsgi_server.CPWSGIServer(('0.0.0.0', 12380)) already shut down
:cherrypy.error[18671] 2010-02-12 13:10:23,717 INFO: ENGINE Stopped thread '_TimeoutMonitor'.
:cherrypy.error[18671] 2010-02-12 13:10:23,717 INFO: ENGINE Bus STOPPED
:cherrypy.error[18671] 2010-02-12 13:10:23,732 INFO: ENGINE Bus EXITING
:cherrypy.error[18671] 2010-02-12 13:10:23,759 INFO: ENGINE PID file removed: '/var/mycherryd/cherry.pid'.
:cherrypy.error[18671] 2010-02-12 13:10:23,782 INFO: ENGINE Bus EXITED

:cherrypy.error[18671] 2010-02-12 13:10:23,792 INFO: ENGINE Serving on 0.0.0.0:12380
:cherrypy.error[18671] 2010-02-12 13:10:23,826 INFO: ENGINE Bus STARTED

puppet log
puppet tries to refresh the service immediately after ensuring it to be 'running'.
Feb 12 13:10:22 localhost puppetd[8159]: (//mycherrypy/File[conffiles]) Scheduling refresh of Service[cherryd]
Feb 12 13:10:22 localhost last message repeated 12 times
Feb 12 13:10:23 localhost puppetd[8159]: (//mycherrypy/Service[mycherryd]/ensure) ensure changed 'stopped' to 'running'
Feb 12 13:10:23 localhost puppetd[8159]: (//mycherrypy/Service[mycherryd]) Triggering 'refresh' from 13 dependencies
Feb 12 13:11:23 localhost puppetd[8159]: (//mycherrypy/Service[mycherryd]) Failed to call refresh on Service[mycherryd]: Could not stop Service[mycherryd]: Execution of '/sbin/service mycherryd stop' returned 1:  at /etc/puppet/manifests/mycherrypy.pp:161
Feb 12 13:11:24 localhost puppetd[8159]: Value of 'preferred_serialization_format' (pson) is invalid for report, using default (marshal)
Feb 12 13:11:24 localhost puppetd[8159]: Finished catalog run in 99.25 seconds

puppet manifest excerpt
class mycherrypy {
  file {
    'rpm':
      path   => "/tmp/${apiserver}.i386.rpm",
      source => "${fileserver}/${apiserver}.i386.rpm";
    'conffiles':
      require => Package["${apiserver}"],
      path    => "${service_home}/config/",
      ensure  => present,
      source  => "${fileserver}/config/",
      notify  => Service["mycherryd"];
  }

  package {
    "$apiserver":
      provider => 'rpm',
      source   => "/tmp/${apiserver}.i386.rpm",
      ensure   => latest;
  }

  service {
    "mycherryd":
      require => [File["conffiles"], Package["${apiserver}"]],
      ensure    => running,
      provider  => redhat,
      hasstatus => true;
  }
}

Answer: Try adding the attribute hasrestart => true to your mycherryd service resource; this will tell puppet to run 'service mycherryd restart' instead of 'service mycherryd stop+service mycherryd start`.
Also make sure the status codes of the init script itself are sane; its often the case that init script authors do not follow the LSB spec for exit codes -- i.e. run service mycherryd stop; echo $? and it should say 0 for a successful exit. If not, puppet's going to have a hard time managing the service and the mycherryd maintainers should fix their script.


How are Ethereum transaction costs calculated?

Question: I'm in the process of learning blockchain technology for a client of mine.   I understand the concept of "gas" in computational costs.    We are looking at creating a crypto-currency as an alternative to using a traditional payment platform for a closed loop solution.   I want to get a feel for the "transaction cost" associated with a simple payment transaction using the ethereum network.
I find the calculation method not totally clear.  Can anyone help?
Comment: is the cost of a simple transaction the same 21,000 for sending any number of ethers? the same for sending 1 ether as for sending 500 ether?
Answer: The calculation is gas*gascost, so a simple transaction will cost 21,000 gas * 20 GWei/gas = .00042 ETH
Comment: You also have to account for any `value` transfered in transaction. So the full formula would be `gas`*`gascost`+`value`.
Answer: Simple transaction that transfers value but have no additional data and not triggers any EVM code (the recipient is not a smart contract) consumes exactly 21000 units of gas. You just need to know the gas price to calculate the cost of the transaction.
The default gas price was 20 Gwei (20 * 10-9 ETH), but it is recommended to use lower value now. Check out ETH Gas Station service for up-to-date statistics about gas price.
You can also optimize costs by sending multiple payments in a single transaction, using a simple smart contract. Not going into the details, a single payment within such transaction will cost you ~10000 units of gas.
Comment: @BokkyPooBah, you have to use a contract for this, there is not other option.
Comment: How would you send multiple payments in a single transaction, using simple transactions. I know this is easily done from a smart contract, but have not seen any code for combined simple transactions.
Comment: How can the price of sending via a contract be constant (10000 units)? Each send instruction will consume some gas so it should go linearly with the number of sends? Care to elaborate?
Answer: I have created a private Ethereum testnet and initiated a transaction of 5 ether from one account to another. The balance in both the accounts is 20 Ether before the transaction. After the transaction:

So, the transaction cost is 0.0004575186 Ether which is approximately 0.00663 USD as of today's exchange rates.
More information about prices can be found at "Appendix G. Fee Schedule" of the Ethereum yellow paper.
Answer: The transaction fee is determined by (gasConsumed * gasPrice). For a simple transaction the amount of gasConsumed is always 21,000 and you can set the gas limit to 21,000 to abort the transaction if a node tries to exceed the expected 21,000 gas.
Right now the suggested gasPrice by MyEtherWallet.com is 21 Gwei, which is basically the "market price" of gas. So you are looking at (21,000 * 21) = 441,000 Gwei to send any amount of Ether today. That's one heck of a deal if you want to send 1 Ether (1,000,000,000 Gwei) which is valued at about $330 dollars right now!
To send 1 Ether you are paying a mere (441,000/1,000,000,000) or .0441% in transaction fees! The great thing about this is if you send 2 Ether the (gasConsumed * gasPrice) remains the same and your transaction cost can be cut in half (441,000/2,000,000,000) .02205%, because it's still just one transaction.
Personally that's an absolutely ridiculous value and I wrote some c# code to pay all the hard working miners 1.5% transaction fees. This way I don't have to care about what I believe others are paying at any given time and what the value of Ether is at any given time.
You're probably better off getting the average if you are a normal user, but with an air-gapped computer your only insecurity is misunderstanding the value of what you hold, so I'm planning on dealing with any possibilities with locally signed transactions at a fixed percentage rate of the wealth I'm transferring.
    decimal gasLimit = 30000;
    decimal etherToSend = .4m;
    decimal desiredFeePercentage = .015;

    decimal 1.5GetGasPriceInWeiForTransactionFeePercentage(gasLimit, desiredFeePercentage, etherToSend); // 200000000000 wei gasPrice for a transaction costing a max of 30,000 gas

    public decimal GetGasPriceInWeiForTransactionFeePercentage(
        decimal gasLimit,
        decimal desiredTransactionFeeAsPercent,
        decimal amountOfEtherToSend)
    {
        decimal transactionFeesInEther = amountOfEtherToSend * desiredTransactionFeeAsPercent;
        decimal transactionCostInWei = transactionFeesInEther * AMOUNT_OF_WEI_IN_ETHER;
        decimal requiredGasPriceInWei = transactionCostInWei / gasLimit;
        return requiredGasPriceInWei;
    }


What are the most important indicators of an high-risk avalanche zone?

Question: If I'm heading out ski touring into an area I haven't been, what are the most important things to look for and think about to avoid high-risk areas for avalanches?
Answer: To expand a bit on the good answer already given:

Slope - 25-45 degrees is a good broad suggestion, but your region of the country will have a big impact on this. Maritime snow is wetter and stickier, so tends to be most dangerous at steeper angles. Transitional and Continental snow is less wet, so has a most dangerous slope range on the lower end of the scale. Find out more specific information from the avalanche center closest to your location.
Any rapid changes to snow position, temperature, or sun. Lots of fresh snow, lots of wind moving snow around, a rapid change in temperature can all increase avalanche danger. The avalanche dragon hates change, and it makes him angry. Stable conditions are less likely to enrage him.
"Whumfing", cracking or visible settling. All very serious danger signs.
Avalanche chutes - look for places where avalanches have happened in the past, by looking for debris, or places where there are no big trees all of a sudden. But also look for evidence of recent avalanches. Check high slopes above you all the time - if you see a few fresh looking slides, that is a huge danger sign.

Forgetting the snow for a moment, remember that an avalanche fatality requires two things - snow conditions, and a person to be there. Avalanche deaths are primarily men, aged 20-29, who are experienced skiers. Not because avalanches like these people more, but because they are most likely to find themselves in a risky location, doing a risky thing.
Group dynamics and decision making will have a greater impact on your survival than snow science (though that is important, too). In nearly all avalanche fatalities, the investigation finds that someone in the group either identified the hazard, or had sufficient training to identify the hazard, and yet the group did the dangerous thing anyway.
Evaluate your group and make some rules:

Everyone has veto power on dangerous situations.
Make several plans. Instead of "we are gonna ski that wicked bowl", decide on a few options in different locations so if one area looks dangerous you are comfortable changing plans.
Don't get lulled into a false sense of security by good weather, or having an "expert" in the group. Everyone's eyes are open, and everyone discusses the situation as they see it.
Don't get macho - if the conditions don't feel right, its fine to turn back. When they say "go big or go home", remember that sometimes it's just fine to go home. ;)

And finally - take a class. Depending on where you are, there are probably some good Level 1 or introductory courses available free or inexpensively. Bring your friends, too - being trained on avalanche safety doesn't make YOU safer, it makes your friends safer. Bring them along and you'll all be more likely to ski another day.
Comment: +1 for mentioning the social dynamics that turn a natural phenomenon into a killer.
Answer:
25-45 degrees of slope. If you can avoid this, you'll avoid most avalanches.
New snow or newly wind-loaded snow.
Unstable snow that collapses under your feet with a "whump".
Pillowy or wavy looking snow.
Recognize an avalanche chute -- an area with missing trees, messed up snow, etc.
Comment: Be aware that snow settling (making that "whumphing" sound) doesn't always indicate a dangerous avy zone, but a dangerous avy condition in general. Whumphs can be seen/heard long before you are anywhere near avy terrain.
Comment: +1 for #5. I'd say that's gotta be one of the biggest signs.
Comment: #5 is the biggest, but #3 is definitely the most immediate. It's a little like hair standing on end in a thunderstorm.
Comment: Can whumps be heard when there is very very low avy danger or are they directly associated with high risk conditions?
Comment: @Ross, they are directly associate with very high risk conditions. The "whump" occurs after some relatively powdery subsurface snow has changed into more granular snow, leaving a little space between that layer and a hard slab above. The "whump" occurs when the slab collapses onto the granular layer. This is a highly unstable combination, and is very likely to slide if it collapses on a steep (25-45 degree) slope. As Greg said, it is a sign of dangerous condition in general, not just in the immediate area.


Is it reasonable to warn people about a bug and provide a workaround?

Question: The title is about it. But, specifically there is a bug
(https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1227365)
which causes no grub menu to appear on loading (even holding down shift). I fixed the problem by running boot-repair. I just wish someone had told me before I had to do a complete reinstall since I couldn't log in in recovery mode...
Comment: Most people wouldn't mind if it(the workaround) is an easy to do though. (I wouldn't mind as long as i don't need to compile anything)
Comment: Either this question is duplicated of [Should questions seeking workarounds for bugs allowed?](http://meta.askubuntu.com/q/5305) or [Posting a workaround for a bug?](http://meta.askubuntu.com/q/5463)
Answer: Is it reasonable to warn people about a bug and provide a workaround in the main site?  Yes and no, to some extent.
If there is a question asked about this bug, then you can answer the question, stating the bug link and that there is a work around.  However, it may be more prudent to state that in the comments of the question instead of an answer, because the question is likely to be closed as a bug report.
However, if you are going to post with the intention of making the public aware of the bug, then you have to be very careful of how you word this.  You need to create a question asking about the symptoms of the issue, then answer your own question with the link to the bug, and also the workaround.
Otherwise you should not do anything except (1) wait for the bug to be fixed, and (2) only answer questions which match this bug issue with the bug link and the workaround.


Is Acceptance by Empty stack and Final state possible in the same PDA?

Question:
$L$ is the language accepted by the above PDA :
$L = \{a^n\mid n\geq 0\}\cup\{a^n b^n\mid n\geq 0\}$ and is deterministic context-free is the language accepted by the PDA how can we accept $a^n$? As it doesn't contain an epsilon transition at the end right ? Is acceptance by both the final state and empty stack possible in the same PDA?
Answer: The PDA can accept $a^n$ because :

Till we don't read a $b$, we stay in start state.
The start state is a final state.

By acceptance by final state, the PDA accepts strings of the form $a^n$.
For strings $a^nb^n$, we have the following :

$X^n$ is pushed on the stack, by reading $a^n$ and looping over the start state.
For the first $b$, pop the stack, and continue to pop till we get only $Z$ in the stack.
When only $Z$ remainded, we have only one choice to do, and even if it's an epsilon transition, because it's the only possible transition at this point, the automaton is still deterministic.

We have also here an acceptance by final state.
In addition, we can define both acceptance by final state and by empty stack on the same PDA, but generally, the two don't lead to the same language. For your language, acceptance by empty stack lead to an empty language, because the stack can never be empty.
Comment: You can take the transition $\epsilon,Z/Z$ even if you aren't at the end of your string, you can take it everytime you want if you can. Also, the transition $\epsilon,Z/Z$ isn't necessary to accept the word, if you are in a final state, the word is accepted, even if you haven't gone through an epsilon transition. You should revise the basics of PDA acceptance.
Comment: sir  but isn't an epsilon transition compulsory at the end of input ?? and can u please show some good source which shows  we can define both acceptance by final state and by empty stack on the same PDA its new to me because i have not seen any such example before :/
Comment: I don't know what you mean by "a compulsory epsilon transition". For the source, there's the wikipedia article : https://en.wikipedia.org/wiki/Pushdown_automaton#Formal_definition (look at **computations**).
Comment: sir what i am saying is the strings in PDA are assumed to be terminated by an epsilon right? so we define the move   ε,Z/Z on the above PDA but similarly for strings of the language a^n also should be terminated by ε right but there was no ε move in the first state


Relation and differences between SGML, XML, HTML and XHTML

Question:
I was wondering what "profile" means in Wikipedia:

XML is a profile of an ISO standard SGML, and most of XML comes from
  SGML unchanged.

According to
http://xml-tips.assistprogramming.com/sgml-xml-html-xhtml-all-together.html:

HTML is a subset of SGML.
XML is a highly functional subset of SGML.
XHTML extends and subsets HTML.

Does "one being a subset of another" mean that code in the first is
also syntactically correct and semantically the same as in the
second?
As in the sense of elementary set theory,

are HTML, XML and XHTML all different subsets of SGML?
do XML and HTML almost not intersect each other?
is XHTML a superset of both XML and HTML?

Can I expect some more concise and clear summation of the
differences in the purposes of the four and/or when to use which,
than the link above? I am really confused about the clear line between their intended purposes.
According to
http://xml-tips.assistprogramming.com/sgml-xml-html-xhtml-all-together.html:

XML is not a single Markup Language. It is a metalanguage to let users design their own markup language.

I was wondering how to understand XML and HTML are both subsets of
SGML, but HTML is a markup language while XML is not a markup
language but a metalanguage for designing markup languages?
Are SGML and XHTML both also metalanguage for designing markup
language?
As in both links mention that HTML is an applicaiton of SGML as well as a subset of SGML, and XHTML is an application of XML. I wonder what differences are between saying one language is an application
of another, and one language is a subset of another?
Answer: HTML and XML are both markup languages (hence the *ML). XML is a generic markup language suitable for representing arbitrary data, while HTML is a specific markup language suitable only for representing web pages.
HTML and XHTML are both subsets only of SGML, except that XHTML has additional specifications so that it also validates as XML. Think of XML as XHTML's influential godfather.
Because of this relationship to SGML across all 3 of these languages, there are a lot of similarities, but they are all considered different languages. However, much of what defines these languages is their restrictions on SGML.

HTML restricts SGML by defining a list of tags that are allowed to be used.
XML restricts SGML by not allowing unclosed or empty start and end tags, and forces attributes to be explicit. XML also has a large number of additional restrictions that are not found in SGML.
XHTML restricts SGML with the tags from HTML (with some exclusions, such as frameset, et al), and with the tag and entity restrictions from XML.

You may find this document helpful, although the technical terms may be hard to digest. http://www.w3.org/TR/NOTE-sgml-xml-971215
XML is not a metalanguage for defining markup languages. Really that's just SGML. XML is simply a data formatting markup language. Your quoted source is using technical terms imprecisely, which is why they are confusing.
Purposes
XML is for defining your own data format. If you wish to pass data between two systems, XML is often the way to do it.
If, for example, you needed to pass a sales order from your website to your billing system, you could create this XML payload:
<code><order id="12345">
    <name>John Doe</name>
    <item id="443">Adult Diapers</item>
</order>
</code>
Your website would then send that XML to your billing system, which could then parse the data from that XML.
XHTML and HTML are obviously just for web pages. XHTML's primary purpose is to remove a lot of the ambiguity that we had in previous years (decades) of web development. Back in the late 90s when I started, we were using HTML 3.2 which allowed for seriously sloppy code. HTML 4+ and XHTML try to remedy that by either strongly suggesting or enforcing explicit closing tags, explicit attributes, and disallowed tags, which makes it easier on both browsers and humans, and avoids unexpected differences in behaviour cross-browser.
Comment: Thanks! (1) Are both HTML and XML subsets of XHTML? (2) Is it correct that neither HTML is a subset of XML, nor XML is a subset of HTML? Do HTML and XML have nonempty intersection, or totally separated from each other?
Comment: (3) What differences are between saying one language is an application of another, and one language is a subset of another?
Comment: There are documents that conform with both XML and HTML; there are documents that conform with XML and not HTML, and there are documents that conform with HTML and not XML. So neither is a subset of the other, but they have a non-empty intersection.
Comment: @Tim: (1) HTML, XML, and XHTML are not subsets of anything except SGML. They are all different. XML actually has just about nothing to do with HTML or XHTML...it serves a different purpose. XHTML can be parsed as both HTML and XML, but it's used only by browsers as HTML markup. HTML and XML both have a common ancestor of SGML, but are otherwise unrelated. For every intent, they are separate because SGML is so generic.
Comment: Honestly I think you're diving too deeply into terminology with application vs subset. I don't think there's a distinction between those terms, or if there is, I doubt it's widely agreed on. Suffice it to say that XHTML borrows concepts from XML and is used as a strict subset of HTML. HTML came first. XHTML came afterwards.
Comment: @Jordan -1 HTML is no subset of SGML, but an application of SGML through the definition of a SGML-DTD. It is absolutely correct to distinguish the defined languages with subset and application. For instance, XML is a true subset of SGML, for that reason you can define new languages with XML, which you cannot with HTML.
Comment: @platzhirsch actually, it turns out that it's not web-compatible to treat HTML as an SGML application. I think XML is now actually an SGML application (not a subset) because it only uses one SGML declaration (or one per version of XML, at any rate), but I can't say for certain because I don't have a copy of any of the SGML specifications so I don't actually know how they define "application". It seems that they had to add some stuff to SGML to actually make it possible to write an SGML declaration for XML, though: something to do with hexadecimal numeric character entities, I think?
Answer: I'm going to start by saying that XML is a subset of SGML, then XHTML is a subset of XML.
HTML is based off SGML but with some different rules.
XHTML is basically an updated version HTML but with some rules put it place so it is also correct XML.
Some notes on how the HTML 5 Standard works with other specifications.
http://dev.w3.org/html5/spec/Overview.html#compliance-with-other-specifications
I'm not sure of the differences between SGML and XML or when you would use one over the other. Although XML seems to be commonly used one.
For XHTML and HTML you are probably better off always using XHTML.  Errors are easier to find and as a bonus it will also be valid XML.
Comment: Thanks! (1) I was wondering how to understand the two seemingly conflicting facts: XML and HTML are both subsets of SGML, and HTML is a markup language while XML is not a markup language but a metalanguage for designing markup languages? (2) According to your reply, XHTML is a subset of XML. XHTML is a superset of HTML as "XHTML subsets HTML" quoted from one link in my post. So HTML is a subset of XML? I am not sure it is true.
Comment: HTML breaks too many rules to be XML.  HTML is closer to SGML I believe.  HTML is loose with tags and there is a set number of different tag types.  XHTML just the XML version of HTML.
Comment: Thanks! As in both links mention that HTML is an applicaiton of SGML as well as a subset of SGML, and XHTML is an application of XML. I wonder what differences are between saying one language is an application of another, and one language is a subset of another?
Answer: The history of these might enlighten you here. Simply talking about meta-languages, profiles, subsets and instances is a little dry ! I'll try to keep it short and simple.
SGML evolved from GML (Generalized Markup Language) which was devised by 3 IBM engineers in the 1960s as a means of storing elaborate legal, government, industrial and military documents. GML was gradually refined till it was standardized as SGML in 1986.
GML/SGML is not a language per se. It is rather a meta-language, i.e. a language to define conforming languages or the "rules" by which formatting of a variety of elaborate documents could be designed in a generally consistent way. Each different type of document would therefore define its own SGML conforming set of tag names plus associated attributes, as well as any defined formal public identifiers/namespaces, schemas, etc. Each format defined like that became therefore a distinct data storage language for the document type concerned. Because of the consistency between all documents conforming to SGML rules, it is possible to write code to collate/process data within these documents and transfer data between documents sharing a common format.
SGML was found overly elaborate for the numerous but smaller-sized document. So XML was developed between 1996 and 2006 as a subset (the word profile effectively means the same as subset) of SGML that could handle both small and large documents. Being a subset of a meta-language, XML is itself a meta-language, though a simpler one. You could say that XML provides a basis for designing document formats suitable for both easy storage and transfer between systems on a network.
After the standardization of SGML but before it was simplified to XML, the internet emerged and with it a need for a document format that enabled easy transfer and display of both documents and loose data. The result was the HTML language, an instance (occasionally referred to as an application) of SGML with 18 pre-defined tags providing a standardized way to display a variety of data types, e.g. text, images, audio, etc. HTML exploited SGML's allowing some elements to omit start- or end-tags. Subsequent versions of HTML added new tags and attributes to it and made obsolete some existing ones. Until HTML 5, changes to HTML were made so that it always remained a child language of SGML.
After XML was standardized, an instance of it called XHTML came out which combined the existing HTML tag names with XML's rigor on tag closing, namespaces, schemas, etc. XHTML initially held the promise of being useful for storage, transfer and display of data. It seemed to be about to replace HTML as commonest way to display web material - until HTML 5 came out. HTML 5 had some syntactic features that went beyond those defined in SGML so as to provide a richer data display, especially for multimedia laden websites. As time went on,  additional features were added to HTML 5 that enriched still more its use for data display/use to the point that it is unlikely to ever be superseded by new XHTML versions, at least as far as display of data concerned. Although standards for HTML & XHTML are done by W3C working groups, actual propagation of these languages "on the ground" is done by progressive web designers and there none more progressive than those working in the media (advertising/PR/marketing) sector: just look at the creativity of advertising agency sites compared to other sites. This sector really took to the new HTML 5 language, delighted in exploiting its capacity for SVG, audio, video and the new APIs. Their ready adoption of HTML 5 led quickly to its popularity among web designers in general, a process accelerated by the online exchange of skills and tricks on YouTube and various other sites. An updated XHTML version, XHTML5, has emerged but it is not really a strict XML derivative but rather a version of HTML5 that is XML-serialized. Only a small proportion of sites appear to have any use for it.
That's the story behind these data languages. I hope it helps you distinguish the meaning and purpose of them all. Philosophically, this story shows how an essential enabling tool (SGML) for a new technology (internet) can, in the new environment with increasingly varied demands, outgrow its original limits yet become conceptually simpler, applicably more versatile and impactfully more powerful.
Answer: Generally in the standards world, a "profile" of a standard is a selection of options that the standard offers: for example, if the standard allows documents to be encoded in UTF-8 or UTF-16, a profile of the standard might require them to be encoded in UTF-8. The term "subset" has a very similar meaning; though arguably the term "profile" is a little bit wider.
Comment: Thanks! (1) How about the meaning of and difference between "application", "subset" and "profile", as in Part 5 of my questions? (2) In "XHTML is the basis for a family of future document types that extend and subset HTML", does it mean XHTML is a subset of HTML or HTML is a subset of XHTML?


How can I translate my ebook?

Question: I downloaded an important PDF e-book but it is not in English. Is there a software or another way I can translate the entire e-book into English or another language?
Comment: when i translate english into urdu google does not tranlate it correctly even i can't understand what translated paragraph is saing.
Comment: For professional e-book translations or any professional book translation I've successfully used: **https://www.ExpertTranslations.com**
Answer: You can upload your PDF to Google Drive, convert it to Google Docs (open with Docs), and apply tool Translate to... English. It will make a copy of the PDF in editable format and also keep the original.

Visit drive.google.com, sign into it with your username and password
Click on NEW > File Upload, select the file from your computer..
After uploading the file, click on 'Recent' on left and and select the uploaded file, right click on it and select Open with >'Google Docs'
When the document will open in another tab, click on Tools > Select 'Translate document'

Enter the document title, choose a language to translate into and click on 'Translate' button

Translated document will open in another tab, which you can edit, print or download to your computer.

Source
Comment: However if the book is that important note that Google translate might not be accurate enough, especially if you need to make references to it elsewhere
Comment: Yes I agree completely. If you need it translated properly, either find another version of the book that was translated professionally, or pay to have it done professionally yourself.
Comment: @JasonDown - Wouldn't the costs of that start in the thousands or tens of thousands of dollars for a modest-length book?
Comment: @Obie2.0: Having a book translated professionally would vary in cost, depending on size, who you hired etc.. This is something you would consider doing for a book you are having published though, not something you just want to read in a different language.
Comment: I followed these steps and ended up with only the first 21 pages translated.
Comment: @Jan, based on the comments in the source linked at the bottom of my answer it appears there are limitations. You may have to do it in chunks :-( ... Things may have changed in the past 7.5 years too.
Answer: Some eBook reader apps are able to translate for you on the fly (I know of two, Google Books and Cool Reader. A better list is in Wikipedia features table).
Please note that this translation isn't guaranteed to be very good, and language support differs between readers as well.
Answer: If you need a professional quality level translation, (as you seem to imply when you mark the book as important), I think that your only option is to hire someone who has knowledge of both languages that can do the work for you. By using any online or computerized service you can't have any guarantee about the quality of the translation.
Comment: I would add that the translator also needs to have domain knowledge of the subject matter in many fields there are terms and abbreviations that are also in standard usage in that language but do not translate directly and there are often borrowed terms that should not be translated, e.g. in psychology and philosophy in English it is correct to use Weltanschauung - it should not be translated from German.
Answer: There are three ways you can do this:

You can use Google translate

You won't be doing this directly.

First, you need to copy the text from the PDF file and paste it on
the google translate.
Once translated, transfer the new converted text to a word document
file.

For PDF format preference: Convert the document file to PDF by clicking File, go to Save as, click PDF in the Save as type list then click save.

You can hire a translator

Freelance translators are available online. You can try to hire on freelancing sites like Freelancer, Upwork or Guru.

You can use an online PDF translator

Online PDF converters and software to translate PDF files directly to English are now available. You just need to upload it to the site
Once uploaded, you need to select the language that your PDF is currently in and select the language that you want it to be converted into
Then click convert for translation and download the processed document

Note: Options 1 and 3 may not be as fluent or may not have the complete slang that the language has typically, but it will do the work. Translators meanwhile may mean paying a fee.
Source
Answer: You can try "Document Translator" for translation of any documents or e-books. It is very easy to use and the translation quality is excellent. It allows me to translate an entire book quickly with a perfectly formatted document. I believe this is a great app
Answer: You can use http://translation-embedder.com which enables you to upload a PDF and get a generated HTML e book. This e book can be opened in any browser - best to use is Google's Chrome. In this new book when you click on the word you will get instant translation and also text to speech capability - this can be turned off. You can view this new HTML e book off line without Internet connection. Application is free to use.You can also read your E book on any mobile phone browser.
Answer: You mentioned the e-book is important, so I would not recommend a machine translation which is meant for casual translations just to get the gist of something.  I'm a programmer and long-time active member over on the main Stack Overflow site, but I've had to have important books translated on a few occasions (both related to programming and not).
If the e-book is genuinely important, then obviously use a professional translation service that specializes in book translations done by an actual person.  I've used ExpertTranslations.com before for a mission-critical book translation in Spanish and they did a solid job.  For a short one in Latvian I used the Human Translator App and they too did a solid job here.  Don't use either if you don't have any kind of budget because they are not free.
For anything not important or if you don't have a budget for the ebook translation, just use Google Translate or DeepL and it will be good enough.  That's what I use 99% of the time and it's never failed me as I can always get the gist of it from those AI translations.
Answer: If you consider using machine translation, try GT4T. It integrates 21 machine translation engines worldwide so that you get always get the best translation whatever your language pair is.
It very easy to use too. Simply drag and drop your PDF files to its interface and that's it.
Download here https://gt4t.net/
Note: I am the developer
Answer: Free translators for books:
EPUB translator https://app-ebt.web.app
PDF translator https://app-pbt-674bd.web.app
Answer: I am using a plugin called "Translate Book" on Calibre. It's not perfect but it works fine.

How can I translate my ebook?


How can I get my ex-fiancee to refinance a co-signed car loan?

Question: I co-signed a car loan with my ex-fiancé.  He is now married with a job and will not get the car refinanced to his name only.  How can I get my name removed from the loan?
Comment: I am sorry to hear about your situation but you have very few options. Get your ex fiancée to share the car with you. Get your ex fiancée to give the car to you assuming you want to take on the full loan. Allow him to keep the car and make no further payments; if he doesn't pay then it gets repossessed. Lastly, I do not understand how the house purchase has any bearing on the car loan; it sounds like that's between him and the other person.
Comment: Get a lawyer.  If you the loan hasn't been transferred then you have a right to the use of the car -- with your lawyer pointing this out to him, he will more than likely refinance it (or agree to sell) rather than give it to you half the time
Comment: A lawyer might be a good idea, but why not in the nicest possible and least confronting manner talk to his wife, ask if she can help you get out of everything with 'their' car. If I know anything about wives, she will not have the 'ghost of his ex' riding around with them in 'their' car. But if she in any way starts an argument just say sorry and leave and go to your lawyer.
Comment: Is he making payments on time? Do you use the car in any way?
Comment: Are you also on the title? That could provide you some leverage in getting the ex to refinance.
Comment: "If you the loan hasn't been transferred then you have a right to the use of the car" I don't believe that is true. Make sure you check with a lawyer before assuming it is.
Answer: Pay off the loan, or convince your ex to refinance and pay off the loan.
You made a promise to the bank to pay back this loan.  You can't remove your liability and shift it to another person because your relationship didn't work out - the bank doesn't care - they want you to fulfill your promise to pay.
Comment: It's not clear whether the OP is unable to pay or whether the OP does not want to.
Comment: The OP can't, but the ex fiancée may be able to. The bank may be willing to change the terms of the loan if the ex fiancée asks.
Comment: Unfortunately, this needs to be chalked up under "why doing business with friends must be treated as business, not friendship." The time to address this was when agreeing to co-sign. If you had put an explicit contract in place that defined what would happen if you separated, you could invoke that. Unfortunately you didn't, which means that unless a lawyer can find some other justification for bringing suit against your ex, all you can do is ask them what it would take to convince them to fix this... or accept that you've painted yourself into a corner.
Answer: If you can stand the risk of a bad mark on your credit, just stop making payments and let him either pay it all himself or default and have the car repossessed.
Comment: I doubt considering they co-signed they can afford a bad mark (if that is what you want to call default and repossession) on their credit.
Comment: @Ross: Presumably since OP cosigned for an ex to buy a car, the OP has reasonably good credit and the ex has bad credit. I don't see how you can conclude anything about whether OP can afford a bad mark from this, but the threat of having the car repo'd might get the ex to take care of the payments.
Comment: It seems we both have presumptions ;) Not enough info in the OP's post really. Was going more for the point of I'm not sure recommending playing chicken is the best course since the outcome could be default and repossession which would affect both parties involved. Hope that clarifies :)
Comment: @Ross: As I understand the question, only the default would affect the OP. The repossession would purely affect the ex. If the title is joint then the situation is different and the OP has more leverage.


Accompanying children for national anthem

Question: Before the beginning of every cricket match, I have seen each and every player from both the sides are accompanied by a child. Why exactly are they accompanied by children ?
Comment: Certainly not a duplicate, but [this Football related question](http://sports.stackexchange.com/questions/663/why-do-players-enter-with-children-on-the-ground) could have similar reasoning.
Answer: I think it is a tradition followed from other sports like football.
See the same question in football.
Why do players enter with children on the ground?
Answer: Basically, it generates more money & more viewership.
Some points to highlight the end result:
If a match starts at 10 AM, then TV programs can start at 9:30 AM, covering the pitch-inspection, the coin-toss, etc. Here the walk-in ceremony will add program time and ADvertisement time on TV. By including some more extras, the TV show can start at 9 AM.
Selection of the children maybe by some contest (make money via SMS, or sales of promotional burgers or drinks etc). The selected children will publicise this with school mates and neighbours, who will be waiting to watch on TV.
We can even consider the walk-in as a mini opening ceremony. If the World Cup Opening Ceremony attracts eyeballs (+ AD money), then the children also attract a small amount of eyeballs (+ AD money).
Even though it is basically a financial choice, now-a-days it can be used for political purposes too, eg by selecting minorities or by supporting some school.


How to get breading to stick to chicken?

Question: I made a simple breaded chicken recipe last night (mixed butter, mustard & bread crumbs together), but the mixture wouldn't stick to the chicken - any tips?
Comment: Let the chicken sit in the coating for at least 5 minutes before frying it. You can also add an egg to improve adhesion, but that isn't completely necessary unless you are doing a double breading.
Answer: This has been answered in a related question : https://cooking.stackexchange.com/a/13878/67
So, to sumarize & relate to your current situation : don't mix your coating together, as you want seperate alternating layers of wet & dry.
Your typical breading for chicken is:

flour, cornstarch, or some other dry powder, possibly mixed with salt, herbs and spices
egg, possibly mixed with milk or water
breadcrumbs, possibly mixed with salt, herbs and spices (but beware that some may burn).

You want to shake or let drip between each addition for nice, think coatings.  If you don't, as dry won't stick to dry, and wet won't stick to wet, you'll end up having a giant slip-plain and things will slide off.
If you're pan frying (instead of deep frying), you might be able to get away with your mix while cooking, but it'll likely come off when someone goes to cut into it.
Answer: You have to get the chicken "tacky". It's great to soak it in buttermilk for a while, let the buttermilk drip off and then bread the chicken. You can also use egg. Some people use flour, then egg, then breading. It all works, but somehow the chicken needs to be sticky for breading like you describe to stick.
Answer: On fish I seen people coat it in yellow Mustard, I kid you not, then breadcrumb, flour it. The mustard can't be tasted after cooking. Given how light a taste fish is, wonder if it would work on chicken?
Answer: I know what you're making is better than shake 'n bake, but the method for that is super simple. Mix your breading, wet your chicken (water, milk, buttermilk, whatever), put pieces of chicken in a plastic bag with with breading and shake it around until coated. Works like a charm.
For thicker breading, and if you don't mind gummy hands, try a 3 stage approach. Set out 3 plates with flour, beaten egg(s), breading. 1) Dredge chicken in flour (flavoured is nice), 2) dip dredged chicken in egg wash, 3) coat egg'd chicken in breading. Done.
Try to do this all with 1 hand so your other hand can touch stuff. It gets thick and messy fast:)
Answer: I've tried egg before, but these days I've switched to non-fat yoghurt. So I:

First lightly fry the panko breadcrumbs in a little oil and cool
(makes for a crispier chicken)
Dredge the chicken in flour
Dip the chicken in yoghurt
Bread the chicken and it sticks wonderfully
Answer: Mixing a little corn starch in with the flour helps the breading to stick
Answer: I've been using this recipe using flaxseed meal stirred into water and allowed to sit for a few minutes. It becomes just a bit gooey and does an excellent job of holding the breading in place: https://allergen-free-cuisine.blogspot.com/2014/10/allergen-free-fried-chicken.html


Identification of ship and seaplane type

Question: Can anyone give clues on the type of ship and seaplane and the time frame?
Comment: I thought we had seen a similar photo on this site recently. Haven't been able to find it (so far).
Comment: Any clue as to nation?
Comment: Biplanes were common in anti-submarine warfare in the interwar years and beginning of World War 2 because of their ability to takeoff and land at low speed from short runways. I believe all nations with an anti-submarine service used them at some point..
Answer: The seamen look USN-ish, the barrels of a heavy triple turret are in view in the foreground. This looks like the quarterdeck of a USN 14 inch gunned battleship in the inter-war period. In fact the aircraft looks near identical to the one in the photo of the Oklahoma allegedly circa 1920 attached. Not that the ship is necessarily the Oklahoma.

US Navy and Marine Corps Museum/Naval Aviation Museum, Photo No. 1985.055.001.038
Further research indicates that the aircraft in question is very probably a Vought UO-1 which means that the original photo probably dates to between 1922 and the late 1920's. Here is a better photo of one of the OU-1s from/on the California (the more I look at this latter photo the more I suspect that the original photo was also on the California and only minutes before or after this one - The officers and men are in the same rig and look at the way the rope on deck in the mid-ground is laying, ... even the shadows are similar sized and oriented):
San Diego Air & Space Museum Archive
Conclusion: the plane is a Vought UO-1 and the ship is the USS California, BB44.
Comment: Looks like you got it, good job!
Comment: Really, that's quite some sleuthing
Comment: Good work. The various ropes on deck show firstly that you are correct, secondly that the OP's photo is before this one. The earlier photo shows the rope coil to the right of the image neatly coiled, the second photo shows that rope has just been used.
Comment: As an "Okie" myself, it is really amusing to see that name on the Oklahoma's lifeboat.
Answer: The ship and plane look very similar to this one:

via San Diego Air and Space Museum Archive's Flickr stream. Another picture in the same stream shows the same scene from a different angle, including the guns.
The ship, its deck and launching mechanism, the plane and its landing gear look almost identical.
That would mean you're looking at the USS West Virginia some time before it was sunk in the attack on Pearl Harbor.
Comment: All biplanes look like biplanes. What about these two is similar beyond being biplanes?
Comment: I think TvF is right here. The plane is most probably a Vought OU-1. The OU-1 was a scouting plane with two seats. It could be equipped with wheels or float gear like here.
The Vought OU-1 went into service in 1922. There's also a single seater fighter version called FU-1 that was used beginning in 1926. Links: [Vought UO-1](http://www.aviastar.org/air/usa/vought_uo.php), [Vought FU-1](http://www.aviastar.org/air/usa/vought_fu.php)
Comment: The identification of the ship is more difficult. It seems that the UO-1/FU-1 were assigned to all major batlle ships of the Pacific Fleet. [Wikipedia](http://en.wikipedia.org/wiki/Vought_FU)
Answer: West Virginia had four twin 16"/45 turrets, so the original photo can't be a Colorado Class battleship.
We need one with a triple turret, like the prior Tennessee class, with 4 triple 14"/45 turrets, which had only Tennessee &California. The New Mexico Class seems to look the most like it, especially as to the angle of seeing the guns with the shorter fantail (Mississippi, New Mexico & Idaho). But the Pennsylvania Class's triple turrets are also a possibility (this included only Arizona & Pennsylvania).
We'll try to ID the plane later, which we're pretty sure is a Vought.
EDIT: Yup, Vought UO-1. Here's a plan of it that lets you see how the nose matches up, the length of the wings, &c.
The photo shows it in a cradle on land, but in this case it's specifically one off the Tennessee. An image search on Google will keep you busy for an hour.

Vought already had a two-seat observation plane, the UO-1, basically a VE with additional fuselage streamlining and a Wright J-3 radial engine.

This was developed into the Vought FU that served 1927-29. The UO-1 first flew in 1922, went into service on the USS Richmond in 1923. After a variety of engines and minor modifications, the last were retired in 1933. (The Vought site.) So your temporal window is 1923-1933. (The earliest possible ships were commissioned in 1916 and retired 1946, let alone the later classes.)
Comment: So we have the plane, and it's one of seven ships, in a 10-year span, but unless you can find something unique in the fantail, that's the closest we can get.