One line answers

Question: IMHO a one line answer that is not backed up by references and doesn't show significant research efforts doesn't fit to P.SE. An example (no offense to Thorbjørn who is actually one of the best contributors): How would you know if you've written readable and easily maintainable code?. Peer code reviews is indeed one of the best ways but this answer doesn't explain why, doesn't give any references, etc. It seems like the contributor didn't have the time to work on the answer. In that case I think that a comment would be more appropriate. Am I right or I'm missing something here?
Comment: Link to version of answer referred to:  https://softwareengineering.stackexchange.com/revisions/141010/2
Answer: Writing a novel when a sentence will do is a bad answer.
Answer: I think that you are partially correct.
A one line answer without any demonstration of experiences or citations of references isn't an example of a great answer. I wouldn't go so far as to say it doesn't fit the site, but it would be something to look at. A short answer that doesn't share experiences or references could be a bad answer, or it could be indicative of a bad question that doesn't elicit the need to share experiences or references.
However, no answer should be posted as a comment, even if it is short enough. Comments are for asking clarification or providing additional information, not providing answers.
Answer: This MSO discussion sums it up well:

Of course, obviously the better answers will generally be longer than one line. To bulk up the content, you might consider doing things like:

linking to the appropriate documentation
including a code sample
suggesting a superior alternative approach
cautioning against some things that people in the same situation commonly do wrong
adding superfluous bulleted lists

There are many good answers that can be written in one sentence. However, the best answers explain the reasoning behind that one line. They explain the thought process that is required to arrive at the correct decision. They may include a personal experience that supports the conclusion reached. I've seen some good answers that take the approach the OP originally thought of and show how it leads to failure, and then present a better solution.
The best defense against harmful one-liners, as with many things on SE, is your voting powers. Don't be afraid to downvote the one-liners!
Answer: Judge an answer by it's quality and correctness, not it's length.
Downvote it if the quality is below an acceptable standard, or the answer is incorrect, but don't discriminate against answers just because of their length.
Also don't forget, you can always leave a comment requesting the user expand their one-line answer into a more detailed response that covers the hows and the whys of the situation. I find many users are quite willing to do this if asked, and it will probably lead to them writing better quality answers in the future.
Comment: I mentioned "a one line answer that is not backed up by references and doesn't show significant research". So it's not just the length. Also, it is unlikely that you can fit in one line references, personal experiences, etc.
Comment: @faif My answer would be the same for one-liners that don't contain references or show significant research. Judge the answer by it's quality and correctness, not by unrelated properties such as length, research shown, or references given. Sure these attributes  *might* indicate a lower-quality answer, but not all the time.
Answer: Note:  I only found this discussion accidentally.
I find it interesting that you consider my answer to be an example of "...a one line answer that is not backed up by references and doesn't show significant research efforts..", and I believe this is not so.
Perhaps the misunderstanding is that you would like explicit mentioning of all the references and all the research effort in the answer.
In this particular case it is simply not necessary.  The laconic style is intentional since lots of wording will just muddle the point being made, namely that you as the author of the code cannot tell, and the computer being a victim of the halting problem cannot either.  You MUST ask another human (or yourself when you have forgotten sufficiently of what you knew when you wrote it).   I believe the number of upvotes reflect that other programmers have enough experience to recognize this too.
So, in this case a one-liner is the most precise way of mentoring the asker.
Comment: upvotes aren't a reliable indication for answer quality [don't you think](http://blog.stackoverflow.com/2012/01/the-trouble-with-popularity/ "The Trouble With Popularity")? For your case, it seems to be more compelling to point out that answer gained only 2 downvotes - with 2K+ views at generally downvote-happy site like ours this sends pretty strong signal that vast majority of readers were able to infer needed context without explicit pointers
Comment: @thorborn I'm not saying that your answer is bad (I up-voted it too). I just don't consider it complete. I think that both sides can do better; You as the contributor can provide more information, and people who like the answer but don't consider it complete should ask for extensions (which is what I'm planning to do from now on).
Comment: @gnat The question is: Should we expect from the readers to infer the needed context?
Comment: @faif [expanded my answer](http://meta.programmers.stackexchange.com/a/3477/31260 "my answer is not an exceptional one-liner - ie no harm in expanding it") with clarification on that
Comment: @gnat you may have a point about the downvotes being a more reliable indicator than the number of upvotes.
Comment: @faif a complete answer to this particular question would most likely be very, very long.
Comment: this is not surprising - yet another point that ["expanding high quality one-liner could do more harm than good"](http://meta.programmers.stackexchange.com/a/3477/31260 "quoting self... :(")
Answer: Your example looks like an awesome answer to me.

- How would you know if you've written readable and easily maintainable code?
  - Your peer tells you after reviewing the code.

Not only does it answer the question, it also introduces important notions of peers, code review and feedback, ties them together and presents in a way that is easy to understand and use.
Answer style is not quite typical, in the sense that most other good answers I've seen at Programmers tend to be more verbose. But since stylistic consistency is not the only criteria I use, this doesn't worry me.
For the sake of completeness need to note that this particular one-liner is pretty exceptional; vast majority of other one-liners I deal with at P.SE are not like that - easy targets for downvote, flag or "expanding edit".

The question is: Should we expect from the readers to infer the needed context?

Good question. My take is

in more typical cases it's better to just err on safe side and provide context explicitly
Mainly because expanding average one-liner does no harm.
in this particular case - yes, it looks reasonable to expect that from a reader
Because expanding high quality one-liner could do more harm than good.

To avoid misunderstanding, I would like to make it perfectly clear that I support general guidelines you referred to. I believe that one-liners are typically not a good fit for Programmers. I also think that providing explicit answer context is as a rule beneficial for the answer quality.
The fact that I may occasionally encounter particular exceptional case (like it was with your example answer) won't stop me from following these guidelines.
Answer: I'd argue that an one-line-answer with many upvotes is an indication of a bad question. An answer that doesn't need citations, explanations or references to be deemed correct is most likely either an obvious answer ("yes, a compiler compiles") or a highly subjective/religious answer ("Linux is better"). Good questions do not provoke such answers, at least not with that many upvotes.

One line answers


Lotus Notes Authentication

Question: I want to setup Lotus Notes on my laptop to mess around with it.  I am trying to setup my email, but my email through verizon.net requires authentication.  I have it setup in Outlook 07, but Outlook does not have support for Databasing.  Does anyone know how to setup authentication for outgoing email in Lotus Notes, let alone is it possible?
Answer: In your personal address book in Lotus Notes (File > Database > Open > names.nsf), go to the Advanced > Accounts section and create a new account.  You'll need to create one count for POP and one account for SMTP to send and receive email.  There are fields in those forms where you can put the authentication info.
Answer: Ken is correct, but I would like to counter Todd's remark (although I didn't vote you down, Todd).
Saying that Notes is crappy because it is not a RDBMS is like saying SQL is crappy because it is not a Network Operating System.  Notes is tremendously powerful at what it does - indeed, it has no rival.  Visual Studion + WinForms is in no way equivalent.  There are things you can do in either Notes or a RDBMS - sometimes one platform will be better, sometimes the other.
Enjoy, Mark.
Answer: Ken Pespisa's answer is correct.
However, you need to understand that the nsf (Notes Databases) are completely flat files.  They are in no way relational.  Believe me, there are plenty of ways you can squeeze relational data into a notes database and everyone of them will leave you with TONS of maintanince nightmares and crappy data.
Mitch's comment to you is dead on, just mess around with SQL Server Express or MySQL.  If you want the RAD aspect of Notes, just use Visual Studio with WinForms or something.
Comment: I'll take the hit, but can someone please explain why this was voted down?
Comment: Your comment does not have anything to do with the question. It just seems to be a "let us bash Lotus Notes"- answer... There is NO truth in generally damning Lotus Notes. of course: if you try to use it as a relational database, then you will fail, as it is NOT a RDBMS. But comparing Lotus Notes with Visual Studio and WinForms is... No i won't say this. I did NOT vote you down, but it for sure was not a bad idea...
Comment: I know this is super old now, but I guess so was my comment when it was commented upon. I was not bashing Notes at all, nor did I say that Notes was crappy. I was saying if you try to make a non RDBMS into one you end up with data in a poor state (fields concatenated together with semicolons or some nonsense like that).

Lotus Notes Authentication


How a stick can provide both normal force nad tension?

Question: This is what I think. Please tell me, am I right??
  If an external pulling force is applied on one end then there will be tension in opposite direction. And if an external pushing force is applied on there will be normal force in opposite direction.
Answer: Stick or any solid object for that matter is a collection of atoms held together by microscopic attractive forces. These forces behave much like a spring in most cases. Imagine that the atoms are held together by small springs. A representative microscopic picture of most(not all) solids would look like this.

So you can think of pushing and pulling a stick much like pushing and pulling on a spring or series of springs.
Note:
Of course I just used the spring as a familiar example to help you imagine the process. In fact most 'springs' you see behave like 'springs' because of the forces between the atoms that make up the spring. That is its actually the other way around. I hope I have not confused you with this last bit.


Overheating a pizza stone?

Question: I bought a pizza stone without realizing that the max temperature it would withstand is 450 F (according to the instructions). My oven goes up to 550 F, which is the temperature I'd rather bake my pizzas at–is it OK to overheat the stone for the sake of the pizza?
Comment: Is it a plain ceramic/stone one? Does it have any kind of rack or handles?
Answer: As always, it comes to the meaning of "OK". The most likely scenario here is that the stone's life is shortened and it cracks. It's impossible to say when this will happen, it could be soon or it could stand up to hundreds of pizzas.
So if for you it is worth it risking the stone, you can do it. If you want to avoid with certainty the stone breaking after 4-5 uses, don't use it outside of the parameters determined by the manufacturer.
Answer: First disclaimers first, "always follow manufacturers' instructions." With that out of the way, the real answer is "it depends." If it has accessories (e.g. handles or feet), or is a composition stone (e.g. solid-surface countertop, which is made of mineral pieces plus bonding agents and filler - think of it like particle board, with a base material of stone rather than wood), then its maximum working temp COULD be limited by one of those other materials. (I have a formative memory of a spatula that melted when used in a hot pan. But I think that sort of inappropriate construction is less common nowadays, and unless your "stone" is made of plastic that doesn't apply.)
If it is a natural stone and nothing more, then it should easily survive whatever heat your oven can throw at it. Keep in mind that your "stone" was (we'll hope) designed for life inside your oven where, even if you baked at just 300 F, it will be exposed to MUCH higher transient temps. In a natural gas oven, for example, the flame will be in the neighborhood of 2,000 C. Granted, the burners will be behind baffles, but during heating there will be air currents that greatly exceed the set cooking temp, and any quality baking piece will have been designed to survive that incidental exposure.
Furthermore, mfr's recommendations (which you really should always take into consideration) can be somewhat arbitrary. There could be any number of legitimate reasons why they stamped it "450^F", but which don't actually mean it's no good at 550. I'm sure you're hoping for something definitive, but what I can offer is a high degree of confidence that unless you see some element that looks delicate and worries you, you can bake your pizzas and be fine. (In my experience your stone killer will be physical shock. I've always worried about thermal shock (i.e. placing a cold item on a hot stone), but I've yet to have a problem with it.
Comment: Corderite pizza stones are also good for much higher temperatures, up to 2000F.  However, that still depends somewhat on the thickness of the stone.
Answer: It depends on the type of pizza stone and the material it is made of, but going up to 800F should be no problem for most ceramic stones.

Overheating a pizza stone?


Button : interactive save as + custom initial path

Question: Is it possible to create a button
whose action is
"save as... in menu bar" with custom initial full path.
(custom initial full path is specified by user.)
Note that if you click save as... in menu bar, a windows pops up suggesting certain full path. That full path is initial full path. If you click save immediately, then the notebook is saved on the initial full path. But if you want to change the path, you can type another full path and click yes. In this sense,
save as... in menu bar is interactive.
So I want to create a save as button, that is interactive,
with custom initial full path,
on a certain notebook.
Answer: Use SystemDialogInput.
NotebookSave[InputNotebook[], SystemDialogInput["FileSave", "C:\\myfile.nb"]]

Comment: Great answer and great built-in function!


What travel documents do I need to travel to Germany from the US?

Question: I am a US Citizen planning on traveling to Germany to visit some relatives in the military.  I don't know what documents I need to have, and the last thing I want to do is show up at the airport (or worse, get to the other country) and find out I forgot something.  So what documents do I need to travel from the US?
Comment: given that the other question requires you to know that germany is schengen, I think this question is clearly different.  Additionally, there should probably be a meta discussion about how hard it is to find answers.  I searched for hours and didn't find the potential duplicate.
Answer: At first I thought "I need a passport".  That part is true for sure.  US Citizens need a passport to get BACK to the US from just about anywhere, so that's important.
Whether you need a visa or other documentation is country specific.  Most of the countries in the EU (Germany among them) are part of the Schengen Agreement.  The Schengen agreement allows easier travel between these countries (i.e. less paperwork).  It currently includes the US in it's reduced travel requirements.
Whether you need a visa or not can (thankfully) be found on the internet.  I found a website that let's you pick your destination and purpose and bam, out comes whether you need a visa: https://visacentral.com/

Ultimately the Schengen agreement says: if you're from an approved list of countries (which includes those in the agreement naturally) you don't need a visa.  Since the US is approved, you don't need a visa.
YOU DO NEED A PASSPORT though.  Your passport is your travel document, and, conveniently, it's the only one you need.
Note: For some parts of Europe, you are also obligated to carry extra medical and travel insurance.  Germany does not have this requirement, but if you plan on traveling around Europe, that's something to check on.
Comment: There are a lot of third party visa sites out there, whose accuracy ranges from excellent to absurd. We generally don't recommend people use such sites to determine if they need a visa, unless it's the company contracted by a national government to process visa applications. For visa information we generally recommend people use official information from the embassy of the country in question, or the visa checking tool (based on Timatic) provided by each airline to its customers, as this information is provided by governments to the airlines so that they can verify passengers' documents.
Comment: Also, for US citizens in particular, the visa advice given at https://travel.state.gov is also generally accurate and up to date.
Comment: @MichaelHampton except the US state department consistently misstates the Schengen passport validity requirement.
Comment: *" US Citizens need a passport to get BACK to the US from just about anywhere"* -  Although a passport is the most common requirement for air travel other methods that prove your citizenship **are** allowed, with some restrictions. See https://help.cbp.gov/app/answers/detail/a_id/3618/kw/passport


What type of op-amp configuration is this from a PLL circuit?

Question: Can someone help me to understand this attached op-amp model? We are using it in an HMC3716 PLL circuit. We don't know how it works, exactly.
Is it an integrator or a differentiator?
Comment: 1.59pf -- those must be easy to source.  Ditto exactly 603pf.
Comment: sorry, Correct PN: HMC3716
Answer: It's a differential input 'broken' integrator, followed by a lowpass filter.
It follows the standard differential opamp pattern, a pair of identical input series impedances, R1x, one to each input, and then a pair of identical feedback impedances R2x + C2x, one from -In to the output, and one from +In to the output reference.
If the feedback impedances had been pure capacitors, then this would have been a differential integrator. The addition of R2x makes this a 'broken' integrator, giving it a finite constant gain and assymptotically zero phase shift above the R2C2 break frequency. Without the resistors, the phase shift would have stayed at 90 degrees at all frequencies, rendering the PLL unstable at any loop bandwidth.
It's worth noting that the R2C2 and R3C3 time constants do NOT set the loop bandwidth, that is set by the loop gain. The R2C2 time constant is set below the loop bandwidth by a factor of at least 3, similarly R3C3 must be above the loop bandwidth by at least a factor of 3. If the break frequencies come closer to the loop bandwidth, the loop stability will be affected, and the loop could oscillate. Many beginning engineers have tried to alter a PLL loop bandwidth by altering the time constants in the loop filter, and come to grief with instability.
Answer: The picture in the question is of the loop filter.  It is a low pass filter, also known as an integrator.
The HMC3761 datasheet shows an example:

The values are different, but the structure is the same.
The loop filter smooths the tuning voltage that goes to the VCO.
A lower cutoff frequency makes the synthesized frequency cleaner, but it also makes it take longer for the PLL to reach lock.
A higher cutoff frequency reaches lock faster, but has a noisier output from the VCO.
Answer: First, it's a differential circuit.  The network formed by C1b, R1b, R2a and C2a is identical to the network formed by C1a, R1d, R2b and C2b, except that C2a is connected to the op-amp output and C2b is connected to ground.  This is a canonical non-buffered differential circuit.
The presence of C1b and C1d suggests that whatever is feeding it is not of zero impedance, so I can't tell you exactly what the gain is.  But the feedback network (R2a and C2a) indicate that it's an integrator with a zero at \$\omega = \frac{1}{R_{2a} C_{2a}}\$.
So -- it's got some low-pass to it, with C1 working against the impedance of the preceding stage, then it's a proportional-integral filter.  That's pretty much a classic loop filter for a PLL.


Userena: How can I get the fields in "edit profile" to save

Question: I have a user I have successfully registered in userena. When I view the profile, the information entered in during signup is properly displayed. I click "edit profile" and am presented with the form. I then noticed this behavior:

View profile (data is correct)
Edit profile then click save (redirected to the same form with all information still filled in)
View profile (newly saved information is gone)
Edit profile and only fill in the "favorite snack" field (redirected to the "view profile" page with the "favorite snack" now showing)
The profile now behaves normally and can be edited and saved like normal.

Why is the proper functioning of the edit profile page dependent on whether I have the "favorite snack" field filled in? Note that "favorite snack" is defined in models.py as outlined in the userena tutorial.
Any ideas?
Answer: I found the problem. It looks like I can allow for a blank field with the following change.
Old Code:
favourite_snack = models.CharField(_('favourite snack'),
                                   max_length=5)

New Code:
favourite_snack = models.CharField(_('favourite snack'),
                                   max_length=5, blank=True)


Windows 7 Lockout

Question: I just changed my domain password and now my account keeps getting locked out.  There must be some process on my machine that attempting to authenticate with incorrect credentials.  How can I find out which programs are attempting authentication?
Comment: Similar: http://serverfault.com/questions/65265/finding-why-a-user-is-locked-out-in-active-directory/65271#65271
Comment: @squillman Thanks, I did not find that via searching.
Comment: @squillman Nevermind, that post is for a SysAdmin, but I am wondering about what one could use from a client machine.
Answer: net use /d *, and also go into Control Panel -> User Accounts -> "Manage your credentials" and remove anything.
Also, check "Scheduled tasks" for anything running as you, and check Services for anything running as you.
And do this on every machine you might be logged into, if you can't run the lockout tools against the DCs to confirm what machine it's coming from.
Answer: I know your question are towards programs on your windows box, but your problem might be solved outside this, as it could be a mobile device trying to connect to an exchange account or similar with the old password, thus locking up your user account
Answer: Likely culprits:

Machines you are logged on to with RDP
Your phone or other device connecting to your work email account
automated processes on your machine (less likely in a normal work environment, but possible)

One way to check which remote machines you are logged on to is qwinsta /server:<servername>. If you are still logged on, you use rwinsta /server:<servername> <session number> to log off the session. Easier than manually logging on to each server, at least. I recently had to do this after changing my domain password.
mfinni's advice is good on checking for local processes. I would add checking any place you have your email account set up, and suggest logging off and then back on to the computer.

Windows 7 Lockout


Why the PercentForm for the y-axis Ticks in Plot function cannot work when specify Frame->True?

Question: I am trying to plot the y-axis value as a percent form. By using PercentForm for the Ticks which I followed Changing tick labels to percent, I can plot the y-axis in percent. However, this approach only works when I do not specify the "Frame->True". Can anybody explain this to me? Thanks
Answer: You need to use the option FrameTicks instead of Ticks:
ticks = {#, ToString[PercentForm[#]]} & /@ Range[0, 1, .1];

Plot[x, {x, 0, 1},
  FrameTicks -> {{ticks, Automatic}, {Automatic, Automatic}},
  Frame -> True]

Alternatively, modify the labels of automatically-generated major ticks:
tickF = Charting`ScaledTicks["Linear"][##] /.
  {a_, _NumberForm, b___} :> {a, ToString @ PercentForm[a], b} &;

Plot[x, {x, 0, 1},
 FrameTicks -> {{tickF, Automatic}, {Automatic, Automatic}},
 Frame -> True]

Comment: Thank you so much, that really helps a lot


What is max voltage in 24V car's cigarette socket?

Question: Do regular adapters for USB work in both 12V and 24V car systems? Would they work with 28-29V (when alternator is running)?
Comment: This probably depends on the quality of the adapter.
Comment: Welcome to Motor Vehicle Maintenance & Repair!
Answer: Most vehicles I've dealt with running a 24v system do so by doubling up with two separate alternators and (at least) two 12v batteries ran in series. Only the starting system uses the 24v while the rest of the vehicle runs off of 12v. They do this so they can run 12v accessories and lights and not re-invent the wheel. In order for it to work they only draw power from one battery. Note: Semi-trucks may be setup differently, using only one alternator producing 24+vdc, but accessories will still most likely be only 12v.
The reason I mention this is, more than likely the cigarette socket will only supply 12v. It is easily checked with a multi-meter. I would suggest your adapter would work just fine, but check the voltage to make sure.


how to design transmitter circuit Ma40s4s ultrasound

Question: I want to generate a pulse that have frequency 40khz and amplitude 20VPP to MA40s4s ultrasonic sensor operate. I use raspberry to generate pulse 40khz-5Vpp then using a IC CD4049BE to boost it into 20vpp as in the below figure. I have encountered the problems is that when i not insert sensor into circuit is waveform is very good but when i insert sensor, waveform is noised as in figure.Please give me how to resolve this problem.
Comment: Your 'scope photo shows only one side of the driver (either TP3 or TP4). The other side should appear similar, with 180 degree phase inversion. If so, I see no problem. You might want to increase C8 (more than 0.1uf) - it should be placed close to U3 power pins.
Answer: Capacitance of MA40S4S (about 2.55 nF) affects output of the power stage.
Consider using an IC with higher output current.
Or you can try a burst generator (mosfet + inductor) driven by the PWN signal. Example you can find on page 9 of AN4841: 12ZVL LIN Enabled Ultrasonic Distance Measurement.


What does it mean to have the same real part after taking the square root of two different complex number(Geometrical Interpretation)?

Question: I have two different complex numbers. Say $a_1+b_1i$ and $a_2+b_2i$. I take the square root of these two complex numbers. Let $ \sqrt(a_1+b_1i) = c_1+d_1i $ and  $ \sqrt(a_2+b_2i) = c_2+d_2i $. I can solve for $c_1~\&~d_1$ in terms of $a_1~\&~b_1$ (respectively $c_2~\&~d_2$ in terms of $a_2~\&~b_2$). I want $c_1=c_2$. I can solve algebraically under which the condition $c_1=c_2$ holds in terms of $(a_1,b_1,a_2,b_2)$. How do I interpret the condition $c_1=c_2$ geometrically in terms of $a_1,b_1,a_2,b_2$? I wish to understand the above condition in a geometrical way with reference to the original complex numbers.
Answer: First of all, "the" square root of a complex number is not well defined, since a complexe number has two opposite square roots. However, is does not matter much.
For a complex point $z = c + id$, you have $z^2 = (c^2-d^2) + 2icd$. So taking $c$ as a constant, $z^2$ lies on the parabola $P_c$ of equation $y^2 + 4c^2x-4c^4=0$ (it is a parabola "turned" to the left, except for $c=0$ in which case the set to look at is the half-line $\mathbf{R}^-$, which is a kind of degenerated and flat parabola). The family $(P_c)_{c \geq 0}$ forms a partition of the plane and two complex numbers have "square roots" with the same real part if and only if they lie on the same $P_c$.
Another way to say it it that the complex function $z \mapsto z^2$ maps the vertical lines into parabolas (except for the vertical axis). In general, complex functions give rise to interesting pictures. You should have a look at conformal mappings.
Comment: After a quick research, I found this [nice illustration](http://mathfaculty.fullerton.edu/mathews/c2003/ComplexFunPowerRootMod.html).
Comment: Thanks. I'm looking on conformal mappings as well. Thanks for the cool link.


Can I launch an image inside lxc as a GUI?

Question: I'm completely new to lxc. I've installed lxc and lxd and created a Linux mint container. I'm getting into and out of mint via the CLI, but as I'm messing around with it I'm wondering: can you, say, launch this and see its desktop environment (provided it has one installed), as in the case of a full-blown VM, or can you only deal with containers in headless mode?
Answer: lxc will not provide anything similar to vm GUI but you can try running GNOME shell as per this article
https://www.linuxjournal.com/content/running-gnome-container
when dealing with container I do  not prefer any kind of GUI as it create multiple process to support GUI itself  and container best practice always prefer single task or process in a container.


Can't install Firebug in FF8, "can't modify the file", how to fix?

Question: I try installing FireBug in FF8, apparently it downloads it correctly, but reports an error when installing. No debug information is shown, just "can't modify the file". How can I debug this installation in Ubuntu (Xubuntu, 11.10)? If it's just user rights issue, it should not be a problem.
Answer: 5) FAQ - FirebugWiki: Installation Issues
5.3) Can't Install Firebug on Windows

Installation Issues
Compatibility Firebug 1.9 will work with Firefox 6.0 up to Firefox 9.*
  (or higher) Firebug 1.8 works with Firefox 5.0 up to Firefox 7.*
  Firebug 1.7 works with Firefox 3.6 up to Firefox 5.*, see however
  known issues. Firebug 1.6 works with Firefox 3.6 Firebug 1.5 works
  with Firefox 3.5 and Firefox 3.6 Firebug 1.4 works with Firefox 3.0 up
  to Firefox 3.6 (1.4.4) Firebug 1.3 works with Firefox 1.5 (1.3.0) up
  to Firefox 3.0 Firebug 1.2 works with Firefox 2.0 and Firefox 3.0
  Firebug 1.0 works with Firefox 1.5 and Firefox 2.0 Firebug Lite works
  with IE, Safari, and Opera Please visit AMO for a full version
  history. [edit] Installing in a clean profile To test for bugs
  regarding interactions with other extensions or corrupted profiles,
  you should do the following. Firefox and Firebug re-install rarely
  fixes problems because the configuration files are not altered on
  reinstall. So to clear out the configuration files you need to create
  a new Firefox profile: [edit] Linux Way Exit Firefox Get to a command
  line Run Firefox with -ProfileManager  $ firefox -ProfileManager
  Create New Profile Start Firefox with your new profile Load Firebug
  into this clean profile. [edit] Windows Way Exit Firefox Get to a
  command line Windows: Start->Run->"cmd" enter Run Firefox with
  -ProfileManager (use quotes around the file name because of the spaces)  "C:\Program Files\Mozilla Firefox\firefox.exe"
  -ProfileManager Create New Profile Start Firefox with your new profile Load Firebug into this clean profile. Read more about this on Mozilla
  Support "Managing Profiles" [edit] Can't Install Firebug on Windows
  Sometimes Firebug just won't get installed in Firefox using Windows.
  The first thing to try is a new Firefox profile above. If that fails
  you can dig deeper. Here are some recommended actions to take: With
  Firefox closed, locate your profile directory, delete these temporary
  files, they will be automatically re-created by Firefox:
  extensions.ini extensions.cache extensions.rdf compreg.dat Disable any
  Antivirus or BackUp program you may have running and then install
  Firebug. It may be that some software is stopping Firefox creating the
  file structures needed for the installation process. Run Firefox as
  Administrator. It may be the same as in reason 2, because firefox
  doesn't have enough permissions. Manually install Firebug. This can be
  done easily, just unzip the XPI (it's a normal zipped file with the
  extension changed) in your extensions folder, inside your profile. You
  should unzip firebug's XPI content inside a folder named
  'firstname.lastname@example.com'. Do this with Firefox closed. To get
  the XPI go to Firebug on Addons.Mozilla.Org, right click on the "Add
  to Firefox" button and select "Save Link As...".
Comment: Dunno why the formatting is screwed when I copy and paste in =S
Comment: CodeBlend, SuperUser.com uses [MarkDown](http://daringfireball.net/projects/markdown/) to format text. When you pasted, the `textarea` outputed the plaintext (as opposed to HTML). This plaintext is not in MarkDown, so the original formatting did not persist.
Comment: @iglvzx ah did wonder, thanks, um how do I get normal formatting in there, for example three lines of text one after the other with only one return carriage?
Comment: Add an extra line between them, while keeping any indentation. :)
Comment: The link was useful, but I use **Ubuntu**, not Windows.
Comment: There is some information for Linux (Ubuntu), where there isn't I believe Google should show you the Linux equivelant =)


DTrace limited on Centos/Fedora

Question: I wanted to work on a problem on a Centos 6 box. I ran dtrace and it failed. It doesn't accept -n or -l or -P or any command line options. It claims to ONLY accept -h, -G, -C, -I, -s, and -o. I figured this must be some weird Centos thing, so I went to verify on a Fedora 22 box. Same issue. It only accepts a very limited number of command line options. I went to try an Oracle box, which is very much RedHat like Centos and similar to Fedora. It worked fine. I was able to run just dtrace and get a long list of all the command line options. I went back to Centos and Fedora. When I enter dtrace, the output is Usage /bin/dtrace [--help] [-h | -G] [-C [-I<Path>]] -s File.d [-o <File>]. So, after an hour of Googling, I've given up. How do you get dtrace to work properly on Centos/Fedora? I've tried both as root and a user. I've searched for packages to increase the functionality. I've tried removing and reinstalling dtrace. The only thing left is to remove the package and install dtrace from source.
Comment: On the Oracle machine, running something like `dtrace -n BEGIN` works (shows the trace). On the Centos/Fedora machines, I get the Usage error because -n is not supported. Almost no command line options are supported.
Answer: The dtrace you find on Oracle Linux is not the dtrace which comes with Linux systemtap and that you will find on every other Linux distribution.
Rather, it is a port of Solaris dtrace provided by Oracle and only available on Oracle Linux.
The two commands are completely different and have different purposes.
The standard Linux kernel tracing facility is known as systemtap, and Oracle's dtrace is just a proprietary wrapper over that. You can always use systemtap directly.
Answer: The dtrace script that comes on non-Oracle linux distros is a little tool from the systemtap project.  It provides only the <sys/sdt.h>-related object/header-file building functionality of solaris dtrace.  It maps it to systemtap data structures, so stap -L 'process("a.out").mark("*") probes will list the instrumentation.
Answer: Now you can use BPFtrace!
https://github.com/iovisor/bpftrace
BPFtrace is a high-level tracing language for Linux enhanced Berkeley Packet Filter (eBPF) available in recent Linux kernels (4.x). BPFtrace uses LLVM as a backend to compile scripts to BPF-bytecode and makes use of BCC for interacting with the Linux BPF system, as well as existing Linux tracing capabilities: kernel dynamic tracing (kprobes), user-level dynamic tracing (uprobes), and tracepoints. The BPFtrace language is inspired by awk and C, and predecessor tracers such as DTrace and SystemTap. BPFtrace was created by Alastair Robertson.

Old answer:
You can install the Linux port of Sun/Oracle dtrace from source here:
https://github.com/dtrace4linux/linux

DTrace limited on Centos/Fedora


Why must energy be increased in a cyclotron to refine measured distance?

Question: I have been listening to Nima Arkani-Hamed's messenger lectures at Cornell, and was confused by one point. He says that in order to measure at increasingly small distances energy must be increased (he was describing the LHC), and that this follows from quantum mechanics. I imagine this has to do with uncertainty, but I have trouble connecting the two. What is it about quantum mechanics that dictates this?
Answer: Measuring something with a particle beam involves scattering the beam off a target (which could be another beam, of course) and seeing what the distribution of scattered particles is. Think of Rutherford's alpha scattering experiment: send a lot of alphas end an sample the scattering angle to determine the structure of the atom.
Heisenberg's Uncertainty Principle imposes a relationship
$$\sigma_x \sigma_p \ge \frac{\hbar}{2}$$
between the momentum of a probe and the size of the area probed.1 In Rutherford's case his alpha particles could easily probe regions smaller than an atom, but could not probe regions as small as a nucleus, so his distribution had two key features:

Most alphas went through barely disturbed
A small number scattered at large angles (even essentially straight back)

leading to the two conclusions that the atom is mostly "empty space" and that there is a small, heavy, charged core in their.
The same consideration apply to the LHC. To examine features of smaller physical extent (say the nucleus or the nucleons) you need a higher momentum probe. For any given particle mass the only way to get high momentum is to dial up the energy. The LHC provides the highest energy beams yet constructed on Earth and can therefore probe the smallest regions.

1 Those in the know will recognize that this should read "between the momentum transfer of the probe and the size of the region probed", but that detail is for another day.
Comment: It occurs to me that that last comment may have been addressed to something other than your actual question. I'll try again in a while to answer the question "How does the momentum enter into the problem when HUP address the uncertainty of the momentum?", which is another matter entirely.
Comment: Thank you for this response, @dmckee. What Im still curious about is why momentum of the probe is related to the area probed.
Comment: @JonathanBasile The short answer is "Heisenberg's Uncertainty Principle", just like it says in the answer. The long answer involves explaining about quantum wave equations and doing some basic Fourier analysis---it's kind of mathy and results in a statement of HUP. The in-between version relies on my telling you that "particles are waves and they can't probe things smaller than their wavelength", which is imprecise. Any way 'round, it works out to be roughly equivalent to the Rayleigh criterion for telescopic optics.
Comment: thanks @dmckee - that sounds like it would get to the heart of my question
Comment: BTW, Jonathon, I haven't forgotten about you, I've just run into a lot of work in the "real" world at the same time as I realized that I don't have an answer on tap. DOn't know when I'll get back to it.
Answer: When detecting anything you are actually analyzing results of some collision. In quantum mechanics, a particle is something that has both, particle and wave characteristics. If you want to detect or see an object, wavelength of a particle must be smaller then this object.
There is a connection between energy of a particle and its wavelength, higher the energy, lower the wavelength and higher the precision.
Comment: ''If you want to detect or see an object, wavelength of a particle must be smaller then this object''
what does this even mean?
Comment: If you want a detailed information about something small you need a smaller wavelength...
Comment: So I was talking about resolution...small details need smaller wavelengths..even the uncertainty principle can be linked to the relation between wavelength and position, or wave number...
Comment: fourier trasform position basis and momentum basis...
Comment: Large spread in momentum means small spread in position..etc..


A conceptual question related to statistical mechanics

Question: Statistical mechanics allows us to consider an ensemble of systems, each of which consisting of only a single particle. Once we write the partition function for the system of one particle, we can easily derive all the thermodynamic quantities. One can accept that the internal energy computed from the partition function is the average energy of the system. But how to interpret pressure? What does pressure mean in the case of a system of one particle.
Comment: Well, start with temperature: how do you define a thermodynamic temperature for a single particle?  Temperature is usually introduced by considering two systems in equilibrium and finding their most probable configuration, resulting in the definition of $T^{-1} = dS/dE$.  But we can safely find a "most probable" configuration only because we assume we have gigantic systems with loads of particles, and therefore fluctuations in energy around equilibrium are small (scale like $N^{1/2}$, while the energy scales like $N$.  For one particle, none of those assumptions hold.
Comment: In this case (and Pooya's great answer for a particle in a box) one can ascribe meaning to pressure, but I just wanted to point out that you can easily get into trouble applying thermodynamics or statistical mechanics to small systems.  The assumptions we use and sweep under the rug can be violated and give really weird results.
Comment: I would also recommend that you have a look at the oldish but beautiful little book "Statistical Mechanics and the Foundations of Thermodynamics" by Anders Martin-Löf (Lecture Notes in Physics 101, 1979). The discussion of the pressure starts on page 23.
Comment: @EntropicallyDriven, can you elaborate your views. I too have a niggling doubt but am unable to express it well and tell what exactly am I suspecting when I derive pressure from partition function for a single particle system.
Comment: @EntropicallyDriven, I see your point. But can we not get over that problem if we assume our one particle system in a heat bath comprising of an enormous number of identical systems, weakly interacting with each other? Let me try proceeding along the same lines to check if pressure can be interpreted likewise.
Answer: Pressure is defined as the rate of increase in internal energy to rate of decrease in volume, i.e.
$$P=-\frac{\partial U}{\partial V}$$
Assume a particle in a box, for example the classic infinite quantum potential well of width $L$. The quantized energy is
$$E_n=\frac{n^2h^2}{8mL^2}$$
In a 3D box this becomes
$$E_{n_x,n_y,n_z}=\frac{(n_x^2+n_y^2+n_z^2)h^2}{8mL^2} = \frac{(n_x^2+n_y^2+n_z^2)h^2}{8mV^{2/3}}$$
where $V$ is the volume.
The ground state energy for this system is
$$E_0 = \frac{3h^2}{8mV^{2/3}}$$ therefore the pressure is
$$P=-\frac{\partial E_0}{\partial V}=\frac{h^2}{4mV^{5/2}}$$
So you can see even a single particle can excert pressure on the boundaries of its bounding box!
Comment: I understand your point. In fact, such a derivation can also be carried out for an ensemble with one particle. Mathematically, I understand what is happening. I am a little troubled by the doubt that we are probably pushing something under the rug - something that Entropydriven alluded in his comment. Let me check out the reference that Yvan has suggested.
Answer: A canonical ensemble is a collection of weakly interacting systems, in thermal equilibrium with each other. The individual systems can be a single particle/molecule if the energy of interaction between the particles is negligible in comparison with their own (kinetic) energy. The energy of ensemble is then just the sum of energies of individual particles, each particle considered as a 'system'. In such situations, one can consider a molecular partition function $q = \sum\exp(-\beta E_i)$, where $\beta = -1/(kT)$ and $E_i$ are the energy levels of the molecule. We can then write the total partition function as $Z = q^N/N!$. (We divide by $N!$ to account for indistinguishability of molecules.) Since the energy of interaction is negligible, all macroscopic effects are a sum of effects due to individual particles. For example, if we have just a thousand molecules in a container of $1$ $m^3$ then the pressure of the gas will be $1000$ times the 'pressure due to one molecule'.
An ideal gas is one example of an ensemble of 'loosely coupled systems'. Another one could be where we can write total energy as a sum of translational, vibrational and rotational energies when there is no coupling between them. One can then write the total pressure as being due to each of these components.
In general, if the partition function of an ensemble can be written as a product of partition functions of subsystems then all thermodynamic functions can be written as sums of contributions from the individual subsystems. (This is because of the logarithmic relation between Helmholtz free energy and partition function.)
Comment: That is not a standard definition of "ensemble". The systems in a statistical ensemble are explicitly NOT interacting, because they are virtual copies/versions of a single system. Really, an ensemble is nothing more than a probability distribution over possible states. It's like if you didn't know where your cat was: you would say there are many possible places where your cat could be ('virtual copies' of your cat), not that there are a large number of weakly interacting cats.
Comment: Nanite, please refer to https://en.wikipedia.org/wiki/Canonical_ensemble for a definition of canonical ensemble. Further, that was not the main purpose of the question.


How can I setup a site with Acquia Dev Desktop 2 beta?

Question: I'm using the new version of Acquia's Dev Desktop beta 2 (https://docs.acquia.com/dev-desktop2) and I want to use it to test and develop on Drupal 8, but it seems tied to a specific set of distributions (ex. commons, COD, Acquia Drupal) and doesn't have the option to install a separate installation. How can I use this for another version of Drupal, besides the versions they are offering?
Answer: To do this, I used dev desktop to create the site instance (instantiating the database and vhost files within Apache) than overwrote that with the install I wanted. Specifically,
I created my site instance normally, selecting "Acquia Drupal" or any of the installations when it asked me to choose a distribution.
For my site settings, I changed it from the long name to 'drupal8' for simplicity
then I went to my local sites directory through terminal and removed the Drupal 8 installation it created (these commands assume OS X environment)
cd ~/Sites/Dev\ Desktop/
rm -rf ./drupal8

Now I can add whatever I like back into this directory, making sure I create it with the same name:
git clone --branch 8.x http://git.drupal.org/project/drupal.git ./drupal8

Now we should be able to install this normally with a couple changes at the install stage. For the database settings, you can use
username: drupaluser
password: <blank>

as Dev Desktop uses these credentials for all the databases.
Under advanced configuration there were two other settings you need to get this to work:
port: 33067
localhost: 127.0.0.1

Comment: Awesome write up :) Presumably you could use this method to run any PHP/MySQL site under Acquia Dev
Comment: Pretty much so Clive. I use it all the time to take over a codebase previously run with a different server. You simply create an empty database and then use Acquia Dev's "import" function. This also lets you use URLs like http://example.dev quite easily. Then you just load the SQL into your empty DB and off and ready. One of the great things for me with ADD running Drupal 6-8 and Wordpress, is you have quick and easy on-the-fly switching between PHP 5.2, 5.3 and 5.4.
Answer: There is an even easier way to do this via drush:
$ mkdir path/to/your/new/docroot
$ cd path/to/your/new/docroot
$ drush dl drupal-8.x

You then simply open acquia dev desktop 2 and select "import local site" and tell it to create you a new database.
Acquia basically handles the rest for you and creates you a fresh database. It will pre populate most of the details for you, including tagging the acquia specific details onto your settings.php file.
The only setting I had to change was the database port (change to 33067) and complete the install.
This will keep your code living outside of the dev desktop docroot but it works just fine. This is the same process I used to import sites I had already developed using a slightly different local workflow prior to using Acquia.


Meaning of 'cf.'

Question:
it refers to a discrete life form that has properties of mind (i.e. experience and character, cf. sentience)
Comment: Cf. https://en.wikipedia.org/wiki/Citation_signal
Comment: Cf. https://writingcenter.unc.edu/tips-and-tools/latin-terms-and-abbreviations/
Answer:
cf., an abbreviation for the Latin word confer (the imperative singular form of "conferre"), literally meaning "bring together", is used to refer to other material or ideas which may provide similar or different information or arguments. It is mainly used in scholarly contexts, such as in academic (mainly humanities, physics and biology) or legal texts. It is translated, and can be read aloud, as "compare".

-wikipedia
Answer: Granted, the literal translation from Latin is "compare to".  In practice cf means "see also".
As explained by MachineCharmer, it is the abbreviation of Latin 'confer' and it is used in several languages in addition to English.
English being a conservative language has many more of these Latin abbreviations of Latin origin: cf 'i.e.', 'e.g.', 'viz', 'et al', 'ca', 'q.v.', 'a.d.', 'vs', etc... ;-) than other European languages influenced by Latin.
Comment: Do you have some sources claiming "in practice cf means 'see also'"? Isn't 'see also' the usage of qv.?
Answer: The NOAD reports cf. means "compare with" (used to refer a reader to another written work or another part of the same written work).
It should not be confused with c.f., which means "carried forward" (used to refer to figures transferred to a new page or account).

Meaning of 'cf.'


Can vairagya (dispassion) and mudita(gladness) co-exist?

Question: Suppose I have attained vairagya or dispassion with regards to the world then is it possible to develop mudita or gladness along with vairagya ? If yes how ?
Is gladness a correct translation of word mudita?
Answer: Yes.
Yogasutra 1.15 (Patanjali)

drista anushravika vishaya vitrishnasya vashikara sanjna vairagyam

Meaning and translation:

When the mind loses desire even for objects seen or described in a tradition or in scriptures, it acquires a state of utter (vashikara) desirelessness that is called non-attachment (vairagya).

The above is the goal. The means to achieving this goal are manifold and include the practice of
Yogasutra 1.33 (Patanjali)

maitri karuna mudita upekshanam sukha duhka punya apunya vishayanam bhavanatah chitta prasadanam

Meaning and translation:

In relationships, the mind becomes purified by cultivating feelings of friendliness towards those who are happy, compassion for those who are suffering, goodwill towards those who are virtuous, and indifference or neutrality towards those we perceive as wicked or evil.
Each attitude is a type of meditation

For e.g., Buddhism has adopted maitri as metta meditation, upeksha or equanimity as samata etc.
Such meditation leads to vairagya. Having achieved vairagya, one continues to exhibit maitri, mudita, karuna and upeksha dispassionately towards all beings.
Read more here:
http://www.swamij.com/yoga-sutras-11216.htm
http://swamij.com/yoga-sutras-13339.htm
Comment: Yogasutra 1.33's translation doesn't seem right, referring to what is written above. Are 1.15 and 1.33 related (i.e. *vairagya* leads to *mudita*)?
Comment: @iammilind It is typically applied to people but can also be applied to experiences which give us happiness, sorrow etc. Vairagya is the goal and to achieve this goal there are several steps one of which is the practice of the four attitudes. Check the first link.


Claims-Based Authorization - how to manage Claims

Question: the last few days I have struggled to understand Claims-Based Authorization, and I have a erious problem to apply theoretical knowledge to a real world MVC website.
Tutorials like http://www.codeproject.com/Articles/639458/Claims-Based-Authentication-and-Authorization are describing the process of installation and the very basics, but are sparse on how to manage the Claims.
Suppose a simple MVC Website which is used to save pictures of funny reindeers.
It is using Thinktecture.IdentityModel, but probably every other Identitymodel would do.
Suppose that Authentication is in place and working.
<code> public class ReindeerController : Controller
    {
        //should be accesible to whole world
        public ActionResult AboutReindeers()
        {}
        //should be accessible to users which are supposed to add Reindeers, e.g. an "Admin" (which is a role, I know)
        public ActionResult AddReindeer()
        {}
        //Only for the Site-owner
        public ActionResult DeleteReindeer()
        {}
        //should be accesible to registred users
        public ActionResult Index()
        {}
    }
</code>
So I have a UserClaims Table which stores a User-ID, the type of the claim as URL and the value of the claim. But this is only the technical foundation of claims - I would like to understand if there is a good schema to create claims and to define what claims a user has / needs.
Answer: Have a look at this (old) post about claims authorization to get an overview.
Then you find some more details here, there are also many other nice posts at thinktecture.
The WIF API description should help you fill inn the blanks.
Comment: Thank you very much, I will have a look!
Answer:
I have a UserClaims Table which stores a User-ID, the type of the claim as URL and the value of the claim.

Sounds like a perfectly fine way to store claims. Your approach is correct, and probably what I would do. My advice is not to overthink this problem, you already have a great solution. :)


Elm327 an app control

Question: Is there a Android App that's used with the elm327 tool to slightly advance  timing on cars?
I know many can read it but I'm looking for the ones that slightly can raise or lower it.
Comment: Welcome to Motor Vehicle Maintenance & Repair!
Answer: While this in essence is a shopping question (and could be closed for that reason), the simple answer to your question is ... No. ELM327 devices are meant for reading what's going on with the ECU, not to write a tune to it. To change the timing (the right way) on newer electronically controlled vehicles you need to change the tune. There are ways which you could change the timing which I'd advise against, like physically changing how something mechanically behaves, but this isn't a good approach.
Also, using a wireless device to write a tune to your ECU is not a wise choice. The reason being is if it loses connection for any reason during the write, you brick the ECU, meaning it will no longer work. When writing a tune, you need to ensure you have a proper stable connection along with plenty of power for the device which is doing the writing. If it loses connection or stops in the middle for any reason ... you now have a paper weight instead of an ECU. Any Bluetooth or Wi-Fi enabled device can also receive electronic interference from other devices, which could interrupt the signal between your originating device and the ELM327, which would brick the ECU. If I haven't stated it already, interruption while writing a tune is a very bad thing.
Answer: I did it manually .I was able to monitor rpm  on ELM , i  adjusted dizzy/ timing to  720 rpm though 700 is the normal idle .jumpered the service wire also.
Running good now..

Elm327 an app control


Why are Davis & Main's perks so much better than HHM's?

Question: In Better Call Saul, Jimmy's perks at Davis and Main seem insanely lavish compared to Kim's at HHM. And D&M is located in a smaller city (Santa Fe vs Albuquerque) and would presumably have fewer clients. What gives?
Answer: We have no means of comparing the two companies' revenue.
The fact that D&M is in a smaller city doesn't necessarily mean the company has lower revenue. The city may be wealthier, and it may have more higher-end businesses and clients. D&M may be a bigger fish in a smaller pond, or the only big firm in Santa Fe, whereas HHM has to compete with other large firms like Schweichert & Cokely. The cities are very close together, so there is probably overlap anyway. In short, there is not enough information to support your assertion that D&M has fewer/less lucrative clients or less revenue than HHM.
Company perks are not tied solely to the company's revenue--the boss's personality matters.
Company perks are decided upon by the partners in that company, which gives a lot of leeway to personality. Unlike Howard Hamlin, Clifford Mains is depicted as quite caring about his employees and overall more of a laid back kind of person (e.g., he plays guitar in his office). Mains is also depicted (and described by others) as very socially conscious. Yes, he is a business man, and a serious one at that, but he is depicted on the show as the kind of boss who would tend to be more giving in terms of perks than Howard Hamlin or Chuck McGill. It should come a little surprise that D&M is perhaps more generous with its perks.
HHM perks are not necessarily as far behind D&M as you suggest.
What are the perks of D&M?

A company car - most law firms provide company cars to their lawyers and allow them to buy them when they leave.  Kim had a nice car when she was at HHM and could have purchased (or picked up the lease) it when she left. Kim did not drive a German car like Jimmy, so D&M was maybe more generous in what it allowed. Or maybe Kim was more modest in her tastes.
A signing bonus - this all depends on the lawyer and how bad the firm wants them. HHM might definitely give a signing bonus to a lawyer they really wanted.
An apartment - Lots of companies arrange corporate housing for high level hires coming in from out of town (Jimmy was from a different city) so they can hit the ground running and take their time finding a permanent home. This was a temporary perk, not something the company provided everyone. HHM might do the same if it hired someone from outside ABQ.
The spacious office - D&M seemed to have much more spacious office spaces, but this is a function of the architecture in the building selected by the partners. Again, this goes to the personality of the boss.
The desk - Jimmy's Cocobolo desk (and the ease with which his assistant got it) suggests a generous employer who really wanted Jimmy to be happy. It is hard to imagine HHM doing the same. This is the one perk that stood out as something HHM wouldn't do.

Overall, the perks at D&M are probably comparable to those at HHM, with the differences being a function of the senior partner's personality more than any other factors. Remember also that the personality cuts both ways. Nobody at HHM would pester you about where you throw your soda cans, for example. The main reason D&M's perks loomed so large is that Jimmy was the one getting them and it is his perspective that dominates the show.
Answer: Note also that Jimmy is coming in at a fairly senior level at Davis and Main — possibly partner? — because he's effectively bringing them a very large and lucrative class-action lawsuit.
Kim, in contrast, worked her way up from the mail room at HHM. At the beginning of Better Call Saul, she's hoping to make partner in two years; after her reputation takes collateral damage from Jimmy's actions, she thinks it'll more likely take five years, and even bringing Mesa Verde to the firm doesn't seem to change Howard's mind.
Kim's further down the food chain, at a firm that seemingly isn't as focused on rewarding its staff.
Comment: Yes, Jimmy's job at D&M was described as "partner track." In most law firms, all of their associates have the potential to become partners through time and good work, so I don't know exactly what "partner track" means. Maybe guaranteed partnership after a specified amount of time with caveats for performance and conduct? Making someone a partner isn't exactly handing them the keys to the firm. Some partners in large firms only own a 1% or 2% stake.
Comment: @ruffdove: sure. I think we're meant to understand that Jimmy's getting somewhat special treatment at Davis and Main. I don't think every associate there has a handsome young assistant sourcing them desks made out of a kind of wood that's fun to say.
Comment: Every associate would have a secretary. In some less affluent firms' associates might have to share a secretary, but him having his own secretary is not a perk, per se. I agree that Jimmy's treatment is probably better than the average associate because of Sandpiper.


How do the Races synergize with the Slayer class?

Question: I'm looking at playing a Slayer in the coming Open Beta, and I was hoping for some feedback from people who had played more than I have in the Closed Beta, about how the racial abilities synergize with the Slayer class.  I understand how all the racials work, I'm more interested in the intersection between said abilities and the game play style of the Slayer class.  Specifically I care about PvP (though, other domains are important to me).
Comment: *TERA* is the name of the game. Since no other games carry that name and it doesn't seem likely to be overloaded on GSE, I'd say go with *TERA*. :)
Comment: I couldn't decide on the correct tag for this game (as Tera is an overloaded term), so I gave two possibilities
Comment: When I looked on [youtube](http://www.youtube.com/results?search_query=tera+&oq=tera+&aq=f&aqi=p-p1g9&aql=&gs_nf=1&gs_l=youtube-psuggest.3..35i39j0l9.9774.9774.0.9807.1.1.0.0.0.0.29.184.108.40.206.) tera online seemed more common than tera.  The google search for Tera gave me a hodgepodge, but tera online was consistent.  That said, I'm not opposed to either one.
Answer: In general, the racial skills in TERA aren't meant to be super-critical in your choice of race.
That being said...

An Aman takes 10% less damage when under 30% health. As a melee class, you'll be toe-to-toe with BAMs and if you fail to dodge (or your dodge abilities are on cooldown) than damage mitigation is nice.
A Baraka can heal to full every 2 hours. They also resist stuns which would otherwise inhibit your ability to dodge.
A Castanic crits more often when behind a mob. As a slayer who parties with others who can tank mobs, this is a nice passive ability.
A High Elf can restore mana to full every 2 hours. Since the slayer's resource mechanic acts like rage (you build it with attacks and then spend it on skills), it can be nice to start at full for some encounters. Overall, though, it's not a great benefit to slayer play style.
A Human takes less damage from other players when low on health and is less susceptible to knockdowns and palatalization (which would otherwise inhibit your ability to dodge).

None of the other races synergize very well.
In the end, I'd choose an aman or a castanic. If you're going to focus exclusively on PvP or PvP is all you will do end-game, then Human is not a bad choice either.
Comment: What is the difference between the Aman and human racials. `Last Aman Standing` and `No Stranger to Pain` seem the same as `Deft Footwork` and `Indomitable Spirit`.
Comment: `No Stranger to Pain` applies to PvE damage as well as PvP damage, whereas `Indomitable Spirit` is PvP only. The threshholds and damage mitigated may be different as well but I'd need to confirm that. As for `Last Aman Standing` vs. `Deft Footwork`, I'm unsure. I'll have to look into that as well.
Answer: Adding onto @Shaun's excellent answer, there's one more thing to consider: hitbox.
Playing as an Aman, you're one of the largest classes in the game. This is excellent for tanking damadge, as the larger your hitbox, the more that you have the chance to block. It also makes it easy for your priest to heal you, as you're easier to click. But for PVP, you stand out like a sort thumb.
And vice-versa for Elin.
Aside from hitboxes and racial abilities, the only other deciding factor of class is aesthetics.
More about races...


Do all artificial satellites have engines?

Question: Novice question. A few days ago I watched a TV documentary about Virgin Orbit's failed mission earlier this year to send satellites into orbit from Spaceport Cornwall. One of the satellites shown appeared to about the size of a shoebox. It was secured inside a compartment pressing down against a spring. At the correct altitude, the door of the compartment was supposed to flip open and the spring would eject the satellite into orbit. This seems a bit of a haphazard means of placing a satellite into orbit. Would the satellite have engines of some sort allowing it to be precisely manoeuvred? Do all artificial satellites have engines?
Answer: Most satellites do have a thruster system of some sort on board. Indeed, the lifespan of a satellite is often determined by how much fuel it can carry, because once it runs dry, it'll start to slip out of its orbit due to a number of physical processes (for example, drag from the few atmospheric particles that get up that high, sunlight pressure, and the earth's slightly asymmetric gravity field). Most of the time, when the fuel is running out, we spend the last bit to kick the satellite into a "graveyard" orbit (an area set aside for nonfunctional satellites where they'll stay well away from the active orbits and are unlikely to collide with anything), or drop the satellite's lowest orbital point far enough that atmospheric drag will eventually bring it down (which may take weeks or months).
There are a lot of thruster technologies, and only some of them resemble a rocket. Hypergolic propellants have historically been popular for thrusters; in that case it's a tiny rocket where the fuel is two materials that spontaneously ignite when they're combined in the combustion chamber, which means you don't need an igniter system. The earliest satellites used cold gas thrusters (cold meaning there's no combustion — basically using an aerosol spraycan to get around) and those still get used from time to time. The new hotness is ion thrusters, which don't really look like a rocket at all. They are incredibly weak and power-hungry, but extremely fuel-efficient, so if you're willing to spend days or weeks inching your way into the proper orbit, that's an attractive option. (A notable user of ion drives is SpaceX's Starlink constellation.)
What you're looking at, though, is a cubesat, which is usually sent up as a ride-share with some larger payload that doesn't completely consume the rocket's lift capacity (for example, if you're lofting an 8000 lb satellite and the rocket can comfortably lift 8400 lbs to that orbit, you can pretty easily add in a cubesat frame and sell those slots to other people). Cubesats are typically tiny — each "unit" is a cube 10 cm on a side that would fit comfortably in your hand. Most cubesats are one unit, though some of them are two, three, or four units stuck together — but still no bigger than a shoebox. In any case, cubesats often don't have any drive system other than the spring that pops them out of the rocket, and they're intended to reach only an approximate orbit and last only a short time. "Haphazard" is a fully appropriate word. They're mostly meant for university students to get some experience with satellite development or get an instrument into orbit on the cheap, so nobody's going to be overly upset if they're off their intended orbit by a few kilometers.
Some cubesats have been pulling off some really neat tricks with orbital maneuvering, though. At that tiny size, it's possible to angle solar cells to use as a light-sail or reposition in orbit by effectively pushing off the earth's magnetic field.
Comment: @Peter4075: The rocket is going 7.8 km/s. The spring mechanism looks to end up at less than walking speed, which is about 1.4 m/s. So, the velocity vector imparted by the spring is less than 0.02% of the velocity vector of the rocket. No matter where you point the satellite dispenser, it is going 7.8 km/s forwards.
Comment: @Peter4075 Not really, no, they just get *approximately* whatever orbit the launch vehicle was in at the time. The spring just gives it a little kick so each cubesat ends up in a slightly divergent orbit. You don't get to ask for any particular angle, it's just wherever the rocket happens to be pointed at that moment. That's the deal -- you get into space on the cheap, in exchange it's a tiny box and you don't get to specify your trajectory.
Comment: So can these cubesats with no drive system be "aimed" in a meaningful way by adjusting the orientation of the carrying rocket?
Comment: @Peter4075 they can have reaction drives for rotational aiming. And with the increasing miniaturization of ion thrusters I'd expect to see (the more expensive) cubesats to employ them as well
Comment: I would think a tiny gyro would be more typical for rotational control of something that small, but I suppose it's possible somebody might use cold gas for the purpose.
Answer: Short answer: no.

most small satellites (like the cubesat you saw) don't have engines. Rocket engines are complex, and therefore expensive, and these small satellites are usually used in an effort to do a low-cost mission.

many large satellites do use engines. These are called thrusters: small rocket engines that are used to change a satellite's attitude. Some satellites can also change their course, this requires larger engines. This is used to e.g. move the satellite into its final position after launch, and to move it to a graveyard orbit at the end of its life.

Rockets are not the only method for changing a satellite's attitude. You can also use reaction wheels, magnetorquers, or radiation pressure (vanes that stick out of the spacecraft and catch sunlight, using the tiny pressure exerted by the sunlight to rotate the satellite).
The advantage of these over thrusters is that they don't consume propellant, so they can be lighter in the long run. Space telescopes also benefit from not having exhaust gases around the satellite (Hubble, for instance: they didn't want exhaust gases to condense on the telescope optics).
Comment: Complex enough that many small, low-cost missions avoid them.
Comment: Pressure-fed monopropellant thrusters aren't very complex at all.
Answer: A nice example of satellites that have no effectors whatsoever are the two Laser Geodynamics Satellites (LAGEOS 1 and 2). Neither has an onboard computer. Neither has any effectors. Neither has any attitude control mechanisms.

< Source: NASA, via wikipedia. This image is public domain.
The LAGEOS satellites are very simple vehicles that orbit well above the atmosphere. They are solid spheres made of a dense material but are covered with retroreflectors. The retroreflectors enable ground-based observers to ping those satellites with lasers, hence the name. The LAGEOS satellites are used to investigate the Earth's rotation and to investigate aspects of general relativity.
Comment: This is exactly what came to my mind when I read the question.  A link to the Wikipedia page and a picture would be helpful.
Comment: @DrSheldon Done.
Answer: In space, simple rules!

This seems a bit of a haphazard means of placing a satellite into orbit.

Agreed, it does seem that way, but when done in a planned and thoughtful way it gets the job done, and in spaceflight where all kinds of things can go wrong and cause big problems.
Propulsion systems are a major headache1 - especially for cubesats and smallsats. If they are ride-sharing on other launch missions or the ISS, then they are the type that can get their job done without being in any ultraspecific orbit.
1They are substantial sources of potential mission failure, they are heavy and take up space which limits what else you can put on the spacecraft, and they are considered "stored energy devices" (reactive chemicals and/or pressurized bottles) and that really complicates the process of getting it cleared to be launched along with other cubesats when hitchhiking on other missions.
They rely on their detumbling systems (attitude measurement and control using solar-electric powered magnetotorquers) to right themselves (without using a propulsion system or expending mass) so that their cameras and other instruments can point in specified directions.
The "haphazard" releases are actually well-planned. For example when released from the ISS they are gently pushed at a controlled speed and specific direction so that they will not ever return and bump in to the ISS.
This applies to both satellites and trash destined for reentry and burnup.

Are the cubesats deployed from the ISS always directed "nadir and retrograde"?
Was this large pieces of "space junk" just released from the ISS in the "nadir and retrograde" direction?
How close will the cubesats be when numerous of them are launched simultaneously?
When jettisoning heavy objects from the ISS e.g. 2.9 tons of batteries+, how much angular impulse does the station get? Corrective actions necessary?
This ISS trash deployment looks more like 2 feet than 2 inches per second, was it too fast or are these articles incorrect?
In "spacecraft talk" is nadir just a fancy word for "down"?

If you look at a deployment from this angle and speed it up, it no longer seems so haphazard:

Would the satellite have engines of some sort allowing it to be precisely manoeuvred? Do all artificial satellites have engines?

Yes, many do and many don't, as pointed out in other answers. But what's really cool is that many use a third option to maneuver. It's somewhat analogous to how a glider (the kind you sit in, or say a hawk when it's not flapping its wings) maneuvers around and goes where it wants without propulsion.
The example I like the best is the constellation of eight CYGNSS satellites that were deployed together and then spread out into a great circle constellation spaced every 45 degrees. These cubesats did not have propulsion, but they did have good attitude control and big flat solar panels that could interact with the drag from the small amount of atmosphere up in LEO.
The technique is called differential drag and is discussed at length in

this answer to Rocket to launch 8 cubesat to LEO at an equidistant distance where I also quote material from Planet Labs who exploit differential drag to help spread their cubesats out around great circles without boost and deboost propulsive maneuvers.

From Differential Drag Control Scheme for Large Constellation of Planet Satellites and On-Orbit Results and my linked answer:

Here is an example of a simulation of the use of alternating between high and low drag configurations to achieve equal spaced phasing and then to maintain it using small station-keeping drag adjustments:

Figure 8: Time-discretized high-drag commands are assigned to achieve desired slots (b) with commands

Figure 9: Attitude modes of Dove satellite enable large drag area ratios (a) Orthographic projections with cross-sectional areas. (b) High-drag and low-drag attitudes


register user only with specific Host name

Question: Hii i want to that whenever any user register at my wordpress that just accepet email of specific host
for example if I want to accept only User register with email@example.com this email format
otherwise that show some error that you can only register with @gmail.com
so how to apply this condition and in which file
thanks
Answer: I think the User Domain Whitelist plugin is exactly what you want:

The User Domain Whitelist/Blacklist plugin limits user registration to
  only registrants with an email address from the domain white list
  below OR prevents registrants with an email address from the domain
  black list below from registering.
Answer: You can use the register_post hook to check if the email domain is in your whitelist and if not just add an error which will tell the user to use an email from your whitelist, something like:
function is_valid_email_domain($login, $email, $errors ){
    $valid_email_domains = array("gmail.com","yahoo.com");// whitelist
    $valid = false;
    foreach( $valid_email_domains as $d ){
        $d_length = strlen( $d );
        $current_email_domain = strtolower( substr( $email, -($d_length), $d_length));
        if( $current_email_domain == strtolower($d) ){
            $valid = true;
            break;
        }
    }
    // if invalid, return error
    if( $valid === false ){
        $errors->add('domain_whitelist_error',__( 'ERROR: you can only register using gmail or yahoo emails' ));
    }
}

add_action('register_post', 'is_valid_email_domain',10,3 );

Answer: Actually, this is a validation question, not really a WordPress question.  You can add a JavaScript file that checks the value of the email field against @gmail.com on submission and either permits the form to submit or alerts the user to an error.
For example, this script would do what you want ...
jQuery(document).ready(function($) {
    $('#registerform').find(':submit').click(function(e) {
        if( ! isGmail( $('#user_email').val() ) ) {
            e.preventDefault(); // Prevent the form from submitting
            alert('You can only register with an @gmail.com email address!');
            return false;
        }
    });
});

function isGmail( address ) {
    return address.indexOf("@gmail.com", this.length - 10) !== -1;
}


One of my start-up drives is missing

Question: I have a Mac Pro (Early 2009) in which I am running two OS's.
10.10 on a Mercury Accelsior SSD and Snow Leopard on a conventional drive. Before upgrading the SSD from Mavericks to Yosemite all was hunky-dory. I could restart between the two OS's using the start-up drive selector in the system folder. Now I have gone to 10.10.3; when I switch from Yosemite to SL and restart from the conventional drive I cannot see the SSD Yosemite Drive in system prefs only the Snow Leopard drive is visible (and the network option)
Restarting FROM SL and resetting the PRAM eventually brings me back to Yosemite.
OR
using the sudo bless command -mount /Volumes/"name of 10.10.3 start-up drive" -setboot
followed by a sudo shutdown -r now
also gets me back into 10.10.3
However I dont like doing this as it feels rather the same as pulling the plug; the Mac is not going through it's correct shut-down process.
A long conversation with Apple arrived at the suggestion I should re-install SL something I do not want to do - too drastic + I may not be able to get back to what I have.
So two questions:
1/. is there a 'gentle' way in terminal I can 'command' the mac to restart from the SSD
and
2/. Is there a way I can 'replace' the start-up info for SSD
Comment: shutdown -r now is a normal shutdown and not like pulling the plug
Answer: Installing Yosemite converted your hard drive to a Core Storage logical volume, and CS was only introduced in Lion (Wikipedia), so it makes sense that Snow Leopard would have no idea what to do with it. Here's how you undo CoreStorage (source - this method worked for me). It should be non-destructive, but as always, take a backup first!
Also, note that any reinstall of Yosemite will re-Core Storage-ify your drive and require you to do this procedure again, and software updates might too. If the issue comes back after a reinstall or update, just go through this process again.

Boot into Recovery HD. If for any reason you don't have Recovery HD, then you'll have to make a bootable Yosemite drive and boot into that.
In the Menu Bar, select Utilities > Terminal.
Run diskutil cs list. You'll get an output that looks like this (credits to the Ask Different user in my source):

Select your Logical Volume ID (the one highlighted in the screenshot) and copy it to the clipboard.
Run the Terminal command diskutil cs revert Paste-Your-Logical-Volume-ID-Here.
Run diskutil cs list to verify that your computer can't find any CS volumes.
You're done! Now Snow Leopard should be able to recognize your SSD's potential as a startup drive again!

One of my start-up drives is missing


Determining percentage of property ownership on all cash transaction

Question: I purchased my home in 2006, paying all cash.  I owned 100% at this time.  My sister wanted to buy into my home and we agreed that she would pay the remodel cost of the portion she wanted to alter so as to have separate but relatively equal spaces within the home.  She paid cash for the remodel.  She has agreed to pay me an additional sum and in return she will be deeded a percentage of the property.
I need to determine what percentage we each own based on these facts.
For purposes of simplicity, my basis in the property is $600,000 and she has contributed $30,000 towards the remodel which results in the total basis of the property now equally $630,000 and is going to pay me $200,000 more. How do we calculate what percentage of the basis we each now own?  (i.e. $600,000 basis, her contribution is $230,000 and my contribution is $400,000).  As we do not want to create a taxable sale/transfer of the part of my interest and will hold title just as joint tenants but not equal tenants and with no survivorship rights, how do we calculate the percentage of ownership?  What is the best way to convey her share?  We have a contract extensively setting out terms under which property can be sold, mortgaged or otherwise encumbered and the division of expenses and will hire an attorney to file all necessary paperwork.  (We have also contractually agreed to the division of spaces within the home and other rights/responsibilities to insure that the cohabitation is fair to both parties and respects each person's private spaces, much like a roommate contract).
A friend suggested I use weighted average calculations, but I cannot find an example which fits our particular factual situation.
Help would be deeply appreciated.
Comment: @PeteB. I think we focus so frequently on the times that monetary ventures with family that go wrong because we never hear about it when they go right. I have had many good experiences loaning money that I knew might turn into a gift. I've had better experiences with family than with friends and acquaintances because I have been in a better position to judge the risk because I spent my whole life around them. (Some siblings I wouldn't ever consider loaning money.) I've never been stiffed by family, and I've never felt bad about saying no to them either.
Comment: Sounds like a tale of woe in the making.
Comment: Is $600k how much you spent, or how much the house was worth at time of remodel?
Answer: The biggest problem is figuring out the current value, and the next is to determine the value added by the $30,000 remodel. (It's probably much less than $30,000.) You may wish to enlist the help of an appraiser in that effort.
If we assumed that your house is still worth $600,000 and discount her $30,000 contribution by 50% (this is probably a very generous estimate) that would give her an ownership stake at $215k and maintain a $400k stake for yourself on a new valuation of $615,000. That would give you a 65/35 split in ownership with her.
If instead we assumed that the value has since increased to $750,000 and give her a more likely valuation of $10,000 on her $30k remodel (bringing the new valuation to $760k) that would give you a $550k stake and give her a $210k stake. This would give you a 72/28 split in ownership.
Why would she get less than her $230k contribution? She is remodeling a house with her own tastes and preferences in mind. She will get to live in that updated house, but there is no guarantee that the next buyer would place any higher value on the same square footage just because it looks the way she likes it. Many homeowners buy a house, remodel, and end up adding less value than they spend. Presumably they enjoy the customized home enough that they don't mind the fact that they can't get their money back in an immediate resale.
Answer:
As we do not want to create a taxable sale/transfer of the part of my interest

She is paying you $200,000, and getting a third of a house in return. Depending on your jurisdiction, that may be taxable regardless of whether or not you actually make a profit.


Trouble with serving local content while using RewriteRule [P]

Question: I'm trying to write rules that will serve files on the new server, while proxying files that don't exist, to the old server.  The proxy rules work fine, sending missing files and directories to the old server.
The problem I'm having is new-server.example.com/blah (/blah/ exists on the new server) is passed through to the proxy rules and routed to the old server.
The reason for attempting the skip is because new-server.example.com/blah falls through to the "proxy section" and passes new-server.example.com/blah/index.php.  Index.php doesn't exist on the new server, index.html does.  The "proxy section" doesn't follow all the index file possibilities in DirectoryIndex, it just looks at the first one.
So I end up with error message, "The requested URL /blah/index.php was not found on this server."
How can this be written so it actually works? --  Thanks.
RewriteEngine On
# skip, proxy section
RewriteCond /var/www/html%{REQUEST_FILENAME}     -f  [OR]
RewriteCond /var/www/html%{REQUEST_FILENAME}     -d
RewriteRule .? - [S=4]

# proxy section
RewriteCond /var/www/html%{REQUEST_FILENAME}       !-f
RewriteCond /var/www/html%{REQUEST_FILENAME}       !-d
RewriteRule ^/(.*) http://old-server.example.com/$1 [P]
ProxyPassReverse / http://old-server.example.com/

# rewrite log
pass through /index.php
init rewrite engine with requested uri /
applying pattern '.?' to uri '/'
RewriteCond: input='/var/www/html/' pattern='-f' => not-matched
RewriteCond: input='/var/www/html/' pattern='-d' => matched
pass through /
init rewrite engine with requested uri /index.php
applying pattern '.?' to uri '/index.php'
RewriteCond: input='/var/www/html/index.php' pattern='-f' => matched
pass through /index.php
init rewrite engine with requested uri /blah/
applying pattern '.?' to uri '/blah/'
RewriteCond: input='/var/www/html/blah/' pattern='-f' => not-matched
RewriteCond: input='/var/www/html/blah/' pattern='-d' => matched
pass through /blah/
init rewrite engine with requested uri /blah/index.php
applying pattern '.?' to uri '/blah/index.php'
RewriteCond: input='/var/www/html/blah/index.php' pattern='-f' =>    not-matched
RewriteCond: input='/var/www/html/blah/index.php' pattern='-d' => not-matched
applying pattern '^/(.*)' to uri '/blah/index.php'
RewriteCond: input='/var/www/html/blah/index.php' pattern='!-f' => matched
RewriteCond: input='/var/www/html/blah/index.php' pattern='!-d' => matched
rewrite '/blah/index.php' -> 'http://old-server.example.com/blah/index.php'
forcing proxy-throughput with http://old-server.example.com/blah/index.php
go-ahead with proxy request proxy:http://old-server.example.com/blah/index.php [OK]

Answer: This is the way Apache has worked since version 2.0: It gets a request, runs that request through all of the RewriteRules, then if the resulting request is a directory, it tries to see if the first DirectoryIndex will work, so it runs that through the RewriteRules and tries to serve the result.  If the first DirectoryIndex entry doesn't work (i.e. it gets to the point where Apache would have served a 404), the server tries again with the next entry and so on.  Your problem, obviously, is that the proxy rules latch on to the nonexistent first DirectoryIndex value and try to send it through the reverse proxy.
I haven't found a general way to fix this behavior server-wide, but there is a workaround.  Use either a <Location> section in your httpd.conf file or a .htaccess file and override DirectoryIndex for that location.
In your case, create the file /var/www/html/blah/.htaccess and put the following into it:
DirectoryIndex index.html


Script / automator action that combines pdfs with the same name from different folders

Question: I'm trying to write a simple script / automator tool that should achieve the following:
I have 600 Pdf-Files in one folder and 600 Pdf-Files with the identical names in a different folder. Now I would like to combine the matching files with each other, so that I get 600 merged Pdf-files as a result.  Can this be achieved?
Comment: Yes, that would be possible. What have you done so far? because this is not a free coding service.
Comment: Please add the script (or a screenshot thereof) of what you have so far. It's way easier to propose ways to improve an existing script than to do everything from scratch.
Comment: Which part are you struggling with, combining two pdfs into one (there are similar questions with answers already on the site), looping through all files in one folder and finding the matching one in the other folder, or something else?
Comment: Thank you for your replies! I specifically have a problem to get the script to match the correct files. I figured out how to combine two files and save them to the right location but I can't figure out how to match the correct files. (I'm an absolute beginner)
Answer: I'd use the third-party command line tool, cpdf, and script the process of merging the PDF documents.
Have a look at: Coherent PDF Command Line Tools Community Release

Download pre-built cpdf tool (This is a direct download link. Building from source is available from link on main page linked above.)
A comprehensive user manual for the PDF tools can be found as a PDF document, or browsable online.
Note: the Community Release version of Coherent PDF Command Line Tools is free fo non-commercial use.

Copy the appropriate cpdf binary executable from the extracted cpdf-binaries-master.zip file to a directory that is in the PATH passed to the shell.

To use the example shell script code:
In Terminal, run the following compound command:
f="mergepdf"; touch "$f"; open -e "$f"; chmod 0755 "$f"

In the opened mergepdf document, copy and paste the example shell script code, shown below, into the document, and then save and close the document.

Note: If you did don't copy the cpdf binary executable to a directory that is in the PATH passed to the shell, then use the fully qualified pathname of the cpdf binary executable in the shell script.

Back in Terminal:
./mergepdf

Outputs:
Parameter missing!...
Example: mergepdf '/path/to/PDF Files 1' '/path/to/PDF Files 2' '/path/to/Merged PDF Files'

Note: I'd move the mergepdf file to a location that's within the PATH passed to shell scripts, then you'd not have to preface the command with ./, or include it's fully qualified pathname.

Example shell script code:
#!/bin/bash

if [ -z "${3}" ]; then
    echo "Parameter missing!..."
    echo "Example: mergepdf '/path/to/PDF Files 1' '/path/to/PDF Files 2' '/path/to/Merged PDF Files'"
    exit 1
fi

oridir="${1}"
dupdir="${2}"
merdir="${3}"

if [ ! -d  "${oridir}" ]; then
    echo "The directory \"${oridir}\" does not exist!..."
    exit 1
fi

if [ ! -d  "${dupdir}" ]; then
    echo "The directory \"${dupdir}\" does not exist!..."
    exit 1
fi

if [ ! -d  "${merdir}" ]; then
    echo "The directory \"${merdir}\" does not exist!..."
    exit 1
fi

while IFS= read -r orifile; do

    while IFS= read -r dupfile; do

        if [ -e "${dupfile}" ]; then
            if [ ! -e "${merdir}/${orifile##*/}" ]; then
                cpdf "${orifile}" "${dupfile}" -o "${merdir}/${orifile##*/}" 2>/dev/null
            else
                echo "\"${orifile##*/}\" already exists in \"${merdir}\"."
            fi
        else
            echo "No match found for \"${orifile}\" in \"${dupdir}/\"."
        fi

    done <<< "$(find "${dupdir}" -type f -name "${orifile##*/}")"

done < <(find "${oridir}" -type f -iname '*.pdf')

What the shell script does:
Finds of all files with a pdf extension in '/path/to/PDF Files 1' and then attempts to find the file of the same name in '/path/to/PDF Files 2'.
If it finds the file of the same name in '/path/to/PDF Files 2' it merges the two files with a pdf extension having the same name to '/path/to/Merged PDF Files', merging the second file to the end of the first file. Note that other command line options for the cpdf binary executable are available.
If a duplicate .pfd document of the same name is not found in '/path/to/PDF Files 2', then a message it output.
As coded, existing files in '/path/to/Merged PDF Files' are not overwritten. If a file exists a message is output.

Notes:
Because the cpdf binary executable is not signed, you'll have to allow it to run by clicking the [Allow Anyway] button in: System Preferences > Security & Privacy > General
The example shell script code, shown above, was tested as an executable shell script in Terminal under macOS Catalina with Language & Region settings in System Preferences set to English (US) — Primary and worked for me without issue1.

1  Assumes necessary and appropriate setting in System Preferences > Security & Privacy have been set/addressed as needed.

Testing under macOS Big Sur 11.4, I did not have any issue with the cpdf binary executable concerning its signing and it simply worked by copying the OSX-Intel version of cpdf to a location that's within the PATH passed to shell scripts.

Note: The example shell script code is just that and sans any included error handling does not contain any additional error handling as may be appropriate. The onus is upon the user to add any error handling as may be appropriate, needed or wanted.


Rift Gameplay - Synergy Crystal

Question: On the Rift Gameplay "Synergy Crystal" how do I add the set bonus stats into the crystal.  Been told a lot of different things but got steered in the wrong direction.  Just returning back to playing Rift and have a lot to learn but it would be a big help if I was being told the truth on how to get the set bonus stats into the crystal (do i buy it, make it, quest it etc;).  Thank you very much and please help.
Answer: You activate the bonuses by equipping armor (left side) that is part of the set. Set membership will be displayed on the tooltip for the armor piece.
You are wearing level 65 armor with a level 60 synergy crystal that are not from the same expansion, so none of the armor in that screenshot will contribute to T'Scain's set.
As of this writing - as well as of the time of question submission - the level cap is 70, and there are even more new sets and crystals, so everything in your screenshot is outdated. It is not worth trying to activate a synergy crystal until you are at level cap.
The general way to do so is (1) get armor from expert dungeons, raids, and/or the RIFT store (for ingame currency OR real money) that has a set and (2) buy a crystal for the set from the RIFT store (for ingame currency, usually also gated by faction reputation).  Note that sometimes an armor piece needs to be upgraded to count towards a set.
Answer: I believe the crystals only work with sets purchased from the rift store.
Comment: Can you provide the source of your information or any more concrete information?

Rift Gameplay - Synergy Crystal


Capacitive proximity sensor size?

Question: I want to design a capacitive proximity sensor to detect human presence at a distance of 10-15 cm.
Now I made my research on this type of sensor but everything that i found doesn't tell me about the size of such sensor, Can anyone help on how to calculate the size of the sensor?
The sensor Shape is circulaire and there is no constraint on it's size but the smaller the better.
I'm using a capacitive sensor because the system that i'm working on isn't fixed in one place, it is portable, so i don't need it to detect any object i only want it to detect human presence and the best option that i found is capacitive sensor which doesn't detect any object but only grounded objects, but if there is  any better option that would be great.
Comment: Capacitive sensors detect objects by measuring the change in an electric field caused by an object.  They will detect non-grounded as well as grounded objects.
Comment: If you're using one electrode, you need a grounded object to change the electric field, non grounded object doesn't have any effect in this case.
Answer: The range is directly related to the size of the sensor.  The bigger the sensor, the bigger the range.
We've been making capacitive sensors at work, directly on PCBs.  In my experience, you can sense presence at a distance of 75% of the sensor diameter.  So if you want to sense presence at 10cm to 15cm, I'd start with a sensor diameter of at least 20cm.

The range in which a probe is useful is a function of the size of the sensing area. The greater the area, the larger the range. The driver electronics are designed for a certain amount of capacitance at the probe. Therefore, a smaller probe must be considerably closer to the target to achieve the desired amount of capacitance. The electronics are adjustable during calibration but there is a limit to the range of adjustment.
  In general, the maximum gap at which a probe is useful is approximately 40% of the sensing area diameter. Standard calibrations usually keep the gap considerably less than that.

http://www.lionprecision.com/tech-library/technotes/cap-0020-sensor-theory.html
Comment: Would you happen to have any other such empirical conclusions on the : 1. trace length (that connects sensor pad to IC)  2. distance from nearby conductors, 3. distance from GND plane.
I've been reading that the distance to GND plane must be maximised so that E-field lines are not suppressed as much, and I'm thinking, why not remove the GND plane from the vicinity completely, so that the sensor pad is ultra sensitive?

Capacitive proximity sensor size?