What does "hold on to your hair" mean?

Question: What does this phrase mean?

hold on to your hair
Answer: "Hold on to your hat" and "keep your hair on" are common English phrases that mean "ready yourself for a rough / exciting experience" and "don't get too excited" respectively. The first is obvious enough, the second is a reference to wigs (more fashionable in previous times, and could come off when the wearer was agitated). Never heard of "hold on to your hair", but it sounds like a conflation of the two.
Google NGram for the three phrases here
Comment: I hadn't previously known that 'keep your hair on' referred to wigs. It used to be thought that excessive stress and worry made men go bald. I always thought it was connected to that.
Answer: I'm almost sure that this is not the sense that the OP is asking about, but: "holding your hair" is a somewhat common phrase in popular culture (certainly American, and some British - think of Bridget Jones' Diary, for example).
When a group of friends or coworkers go out to a bar, it is unfortunately rather common for one or more of them to drink until they vomit.  A true friend is said to be one who will hold your hair out of the way, so that it doesn't either trail in the toilet or get splashed with vomitus.
Taken literally, it only applies to drinkers with very long hair - usually, but not always, young women - but it's also used as a figure of speech when one friend is suggesting some risky or unwise behavior:  "My roommate and I are going out on the town tonight.  Why don't you come along and hold my hair?"

What does "hold on to your hair" mean?


Has anyone attempted to simulate the creation/development of a language?

Question: I suspect this is a dream confined to sci-fi for at least a few decades, but, I'd like to know if anyone has ever tried to create a computer model for the creation of a language, or at least researched into the same. Or perhaps attempted to simulate/extrapolate the development of an existing language.
Comment: There are lots of people who [invent languages](http://conlang.org/), but you seem to have something else in mind. Can you clarify? I'm not sure I understand the question.
Comment: You're right, I'm not thinking about conlangs. Rather some model that predicts how a natural language might change and develop over time.
Comment: There's a great book, *In the Land of Invented Languages*. And there's a great post about the book on a great site about languages: http://languagehat.com/the-bookshelf-in-the-land-of-invented-languages/
Answer: This would be a fascinating project if it were feasible, but unfortunately it's well beyond the current state of knowledge about linguistic change; and even if we knew much more than we do, it's still possible that language would turn out to be too complex and ill-bounded a system to model at all adequately.
We don't know enough about how, and especially why, language changes to be able to model it. For example, we know what kinds of sound changes are frequent in languages, but we don't know why they happen when they do in the languages that they do. We know morphological analogy happens, but we can't predict when it will happen and in what direction. Syntactic change is even more mysterious. Etc.
Many of these phenomena have their roots in realms that are not (or not purely) linguistic, e.g. acoustics, sound perception, communicational pragmatics, or even random facts of cultural history, so you'd have to model all these as well. And language change arises from usage, not from the abstract structure of a language, so you'd have to model language use in all its contexts. Basically, you'd have to model a world.
This is not to say that it's impossible to model very specific, limited aspects of language change. Adam Albright claims he has a model that successfully predicts the direction of analogical change given certain usage statistics. Probably there are other such small-scale attempts out there, which maybe others here can mention. But a general model of language change, unfortunately, is almost certainly more than a few decades away.
Answer: Nobody, has modeled the whole of language development (to many moving parts, although a kind of a SIMS game with language would probably not be out of the realm of possibility). But there have been models of certain parts.
Some people working on the newly opened area of language evolution/origins have conducted experiments that they used to model the changes in meaning. Simon Kirby is well known for his experiments. There's a whole centre for Language Evolution and Computing at the University of Edinburgh: http://www.lel.ed.ac.uk/lec. He describes some of his models in this lecture: https://www.youtube.com/watch?v=f3-R3Ii35nY and more details can be found here: https://www.era.lib.ed.ac.uk/handle/1842/3283.
Of course, modeling of language change goes all the way to the postulation of sound change laws in the Indo European languages. But computational modeling is much more recent and not nearly as common. Most models are concerned with child language development or adult learning.
Comment: Luc Steels did a lot of the early work in this domain, and Andy Wedel has done a fair amount of work in models of sound change.
I did a bit of agent-based modeling work (following up on initial work by Mark Dras) looking at the evolution of systems of vowel harmony.
Comment: A Sims game with language development would at least be a nice break from the sim-speak they already use.
Answer: It depends on the scale you're referring to. There is certainly active research in artificial language learning, agent-based and social network modeling of language evolution, novel language development by robot agents, social effects (micro and macro) on linguistic change, word formation constraints/factors, 'telephone game' experiments on language convergence, and so on.


How can I set Mac OS X Lion to use browser GMail as a default mail app?

Question: I have set up Chrome (my primary browser) to use gmail when I click an email link.  However, when I right-click a file on the desktop and select "New Email with Attachment" OS X launches Mail.app.  Is there a way to make it open a gmail compose window tab in my browser instead?
Answer: The New Email with Attachment service is a feature of Mail. It is built into Mail, and Mail provides it as a service to other applications.
I wonder if you could use this but modify it to point to the code written below (the method you are using to make this work in Chrome)?
Answer: There are different instructions for different browsers here.
As an example, this is for Chrome and Opera:

Launch a new browser window and open up Gmail
Open the Javascript console by hitting Command+Option+J and then paste in the following:

navigator.registerProtocolHandler("mailto",
  "https://mail.google.com/mail/?extsrc=mailto&url=%s", "Gmail");

and a bit of clarification from further down the page...

*After entering CMD+OPT+J, notice to the right of the "x" where you can close out, a series of choices: "Elements, Resources,
  Network…etc…Console". Click the "Console" and paste the code to the
  right of the ">" symbol and then close out. Then, as the above
  directions show, Gmail will then prompt to accept the confirmation at
  the top of the browser window.

Accept the confirmation at the top of the browser window and try out a mailto link
Check out the link though if you're using a different browser.
Comment: Thanks for taking the time to respond Josh.  However, this solution only accomplishes what I state in the question above that I am already able to do (use gmail to open email links when I click them in Chrome).  I am specifically seeking a way to launch GMail when I use 'mail links' from OUTSIDE THE BROWSER itself, i.e. with the "New Email with Attachment" option from the context menu when right-clicking a file on the OS X Desktop.
Comment: Ah, you're right of course.  :)


Arduino 4G LTE Shield

Question: Is there by any chance a shield that can take an 4G LTE compatible SIM card activated by a carrier and establish a connection?
Answer: Googling "4g shield arduino" gave this. It will need a 4G LTE capable SIM, but I guess "it depends" if any 4G LTE SIM will work..
Answer: This is a really old post but I also found this LTE shield which is much cheaper than the cooking hacks one.
Be carefully; this module is a dual band only (900/1800 MHz); no 850 or 1900 MHz.

Arduino 4G LTE Shield


How do I stop my under cabinet light plastic covers from falling down

Question: In our kitchen, we have under cabinet lights. The  plastic covers keep falling down.  The covers click into place just fine.  But after a few days they fall down.  Is there a way to secure them?  Obviously, I don't want to use super glue.
Answer: I guess that some clips or other parts that make this 'click' work are not catching firmly and/or are bending as because of temperature. I would try to adjust them if possible (if these are like metal parts) to grip more firmly.
If that doesn't work You can either remove these light covers and make a complain in a shop You ordered them (as it shouldn't be a proper way of behaviour) or use less elegant ways to make them stay in place (duct tape on other side - not visible to You). Super-glue or something isn't welcome.
Answer: You might try cutting strips of 3M adhesive Velcro, if there's a suitable place for both the hook strips and loop strips to be sufficiently concealed.
Alternatively, you might be able to put something behind the 'clicking' hook so that the hook doesn't withdraw from the cover. (I'm thinking folded paper, or rubber, or foam)
After that, depending on style of the cover, I'd try to find or make a wire spring loaded to hold the cover in place. The friction at the two ends of the wire should be plenty to hold a plastic cover against the force gravity, hook or no hook.
Answer: They loosen over time, and it's annoying.  Ultimately, the only true fix is to replace the light with a new one that has its initial grip, and hasn't been removed for bulb replacements over the years.
However, to avoid adding something to your light lens that may be affected by the heat, just a trace of beeswax applied around the interior of the outer trim will add some 'sticky' which is usually enough to keep the lens in place.  Not too much... just a little.
If using the velcro idea, or any other approach which adds material affected by heat, consider changing your bulbs to LED.  (This will also keep you from getting burned if you touch the light accidentally, it keeps heat out of the cabinet, it allows you to set things directly under the lights if you need to, and it might even save a dollar's worth of electricity.  The LEDs used to be much dimmer than the halogen, but they have gotten much better.


Potential at infinity due to a point positive charge

Question: I know it is quite basic for this site, but I am confused...is it just a convention to take it as zero, or there is some logic? I really dont think that V = kq/r r->infinity, v -> 0 is right, because this is circular reasoning, as this formula already assumes V at infinity equals zero. Please tell me if this is a convention with no logic or there is some underlying principle.
Answer: Potential is always uniquely defined, but only up to a constant.  It is potential difference that is the physically meaningful concept.  So you can set the zero of potential anywhere, as long as it is consistent, i.e. the potential difference  between 2 points is correct.  It is usually convenient to set the zero of potential at infinity, but not always, such as for a electrically charged plane.


Incorrect time on .ics invitations

Question: All of my calendars are on iCloud (synched to Outlook 2013 on Win7, and on my iPad and iPhone). At least most of the time (possibly every time) I receive an .ics meeting invitation, the time is incorrect. This seems to be exclusively tied to time zone differences, but makes no sense.
For instance, I received an invitation yesterday from someone in California (PST). They had set the meeting for 08:00 their time. I am in EST (+3 hours). The invitation (and the resulting calendar item after I accepted) show as 10:00 for me. Clearly this is neither my time zone nor the originator's. When I look at the entry in iCloud, it shows a "Floating" time zone. I cannot change the time of the event in any of my tools (Outlook, iCloud, or iOS), presumably because it of restriction of permissions on events created from an invitation. I also cannot delete the item (without rejecting the invitation), so my only recourse has been to create a duplicate entry at the correct time, hoping I won't be confused by this in 6 weeks on the meeting date.
Is there any way for me to handle these .ics invitations and have them end up showing properly in my calendar?
Answer: http://lanyrd.com/help/timezones/
iPhone calendar settings live in Settings -> Mail, Contacts, Calendars -  select "Time Zone Override".
I turned it off and it resolved the issue with the time zones

Incorrect time on .ics invitations


What are the code requirements for installing a ceiling fan alongside a fire sprinkler?

Question: I have a fire sprinkler in my bedroom ceiling which is right in the middle. I want to install a ceiling fan.  What are code requirements to follow?
Comment: I believe it's 24" clearance from the sprinkler horizontally, and 18" vertically. So if the blades of the fan are 18" below the sprinkler, and the motor is 24" away. You'd have a giant fan, but you'd be within code.  NFPA 13 covers this, from what I could find, but I don't have a copy of it.  Best to ask your local government.
Comment: [Related](http://diy.stackexchange.com/questions/8292/how-close-can-light-fixtures-be-to-fire-sprinkler-heads) (includes the NFPA 13D cite I was after)
Answer: It depends on what jurisdiction has authority where you are doing the work. Some sort of electric code applies, but there's nothing unusual involved. There's a requirement for the fan to be securely anchored to the structure. That could be electrical, mechanical, or building codes. They are unlikely to be very specific, "securely anchored" will be roughly all the detail you'll see.
The main issue is the sprinkler head. It seems every jurisdiction has their own requirements, though at least in the USA, the National Fire Protection Association (NFPA) publishes a model code from which most jurisdictions either adopt by reference or base their own code upon it.
The main provision here will be nothing can be installed to obstruct the dispersal pattern of the spray head, which normally means the head needs to be lower than the fan. However, one could argue if the fan were pendant mounted by a narrow tube, one could actually get a better dispersal with the head at ceiling height because the head is higher and the tube provides minimal obstruction. This argument may or may not be viable, depending on exactly where the two components are located relative to each other.
Since this is a judgement call, only the authority having jurisdiction can make such a ruling.
Answer: Since you are in a residential occupancy, you will have residential-type sprinkler heads fit, which means that NFPA 13, section 188.8.131.52.1.3 (or the equivalent citation in NFPA 13R or NFPA 13D) applies:

18.104.22.168.1.3* Unless the requirements of 220.127.116.11.1.4 through 8.1 0.6.2.1.9 are
  met, sprinklers shall be positioned away from obstructions a minimum distance
  of four times the maximum dimension of the obstruction (e.g., truss webs and
  chords, pipe, columns, and fixtures). The maximum clear distance required shall
  be 36 in. (0.91 m) in accordance with Figure 184.108.40.206.1.3.
Comment: "maximum dimension of the [fixture]"  Would that be blade diameter, or the motor size?  If blade diameter, then any sprinklers would likely have to be installed outside the building.  Imagine a 96" fan, where the sprinkler head would need to be 32 feet away, possibly in a neighbor's house...  But then the maximum of 36" applies, completely invalidating the whole idea of obstruction?
Comment: @SO_fix_the_vote_sorting_bug -- it's the motor size that governs here, as fan blades > 50% open can be disregarded for sprinkler obstruction determination purposes (see 184.108.40.206.1.9)
Comment: Would the clearance requirements apply if there were heads on both sides of the obstruction?
Comment: @supercat -- it'd be a very weird setup (or a very weird obstruction) if you had heads within 36" of both sides of the obstruction (normally sprinkler heads cover more area than that!)


Central Furnace blower alwas on, even with thermostat disconected

Question: A technician told me it was the electronic control board that has the blower relays on it , I replaced it and still has the problem, I've been reading here online about a limit switch for the blower but I don't see it in my unit. Where else should I check, no heater and no AC
Comment: What is the make and model number of the unit?  Can you include a high quality photo of the schematic (should be found printed inside the unit somewhere)?
Answer: The limit switch isn't on the control board; it is an external part that is mounted in the plenum above the burners.  Wires run from the control board to the limit switch.
If you also have no heat and no AC, then check that there's 24 volts present on the control board.  Some control boards have a normally closed relay that turns off the fan by pulling their switch open after power is applied.


Difference between Localhost and opening html file

Question: What is the fundamental difference running a file using a server in localhost, and opening a file such as file:///Users/$user_name/$your_directory/index.html, assuming no backend is used, and it is only frontend and contains html/css/js
 How does this also affect interactions with other server ie. ajax requests?
I am sorry if this is too broad, but I haven't found a solid answer to these underlying questions.
Answer: Fundamentally, assuming at some point you're going to host the result on an actual web server, the former matches the target environment while the latter doesn't. Browsers treat local files and files served from web servers (even localhost web servers) differently, although very similarly. One aspect of this is the encoding: When you retrieve a file from a web server, the process of determine what encoding the data is in is different from opening a local file.

How does this also affect interactions with other server ie. ajax requests?

This is one of the primary ways in which they're handled differently, and it even varies from browser to browser. A page loaded from a file:// URL has origin null from a Same Origin Policy standpoint. Some browsers (like Chrome) disallow Cross-Origin Resource Sharing entirely for origin null, even when the server you're trying to talk to has a wide-open CORS policy (*). Others (like Firefox) allow origin null to match the wildcard.
In general, for best results, ensure that your development environment matches your deployment environment in the important ways. That means doing your development using a web server process rather than local files. Most IDEs will happily provide that process for you; if not, Apache or Nginx aren't hard to install.
Comment: This answers the basis of my question! My problem which sparked this questions was actually CORS error. Thanks for your help
Answer: answer is simple,
if u don't have made active backend yet for "index.html" then it would not effect.e.g.-"localhost" and "index.html" will be same this time.
but when u start working with the backend,then most of the backend processes need an active server (need localhost).
e.g.-
1.
fetch('local.json')... //fetch json or any file would not work for local files.
2.
u may not ineract with mysql/django etc. databases.
means it cause errors in signup/login , store any image/video/docs at database etc.
so better is work in localhost, it's most easy way is :-
VScode(IDE) >> extenctions >> live server (just need to click a button to make
localhost and click again to stop localhost)

https://marketplace.visualstudio.com/items?itemName=ritwickdey.LiveServer
Answer: It won't make any difference, I think.
But there is an exception when using Chrome! Sometimes I have seen if a html file is added with some CDN link, then it doesn't loaded into html specifically in Chrome but if you try the same file in Firefox or Internet Explorer, it works.
I have faced this problem and hence I always put it under local IIS default website.
Comment: @Those, who are negative marking should atleast share their thoughts and tell what's running in their mind!


Should I flag my closed question after editing to receive attention?

Question: I worry that my question after edited won't be seen. Should I flag it? And in case it's still not qualified to be reopened, can I ask on the flag to tell me which one are still unclear?
Answer: No, you shouldn't flag your closed questions so that it will get reopened.
Flags are not for that purpose. Flags are designed to bring inappropriate content to the attention of the community.
From the help center

Flagging is a way of bringing inappropriate content to the attention of the community.

If you edit your post, it will be immediately bumped to the homepage. So, users will see that post. More over all the closed questions will be put in the reopen review queue if they are edited or they have a reopen vote on them. So, the users with close/review privileges will attend the review and reopen if the standards are met.
So, there is no need to flag your own post or any other post. They will be declined.

Can I ask on the flag to tell me which one are still unclear?

You can ask it in the comment section. If the post is flagged and reason is asked there, only the moderators can see it but in the comment section, all the users can see it and respond you what is wrong with the post. It helps in reopening the post quickly than the moderator intervention flag.
But I saw some advice on other meta posts that I should flag to get further attention for reopening!
This is severely outdated advice, from the time when recent edits wouldn't push questions into the reopen queue, and the only way to draw further reopen votes beyond the homepage bump was to flag or request on meta. The system has changed considerably since then, and the "moderator intervention" flag is now to be used only in cases where only a moderator can handle things.
About requesting on meta: per the most recent FAQ, you should only do so if 1. you have exhausted all appeals (editing, voting, and commenting) but it still wasn't reopened, or 2. you commented but didn't receive that much clarification about why your question was closed.
Comment: Does going to the review queue always happen after an edit? For example I edit and it still be declined, will another one pump it up again?
Comment: I think no. It goes to the review queue after the first edit. If the question is okay, then users vote to reopen. The review is completed if 4 users or a mod attend a review.  the reopen request will be declined if majority of the users vote for "Leave closed". But other users with privileges can vote directly clicking on the question even it is out of the review queue. It will be in the review queue until 4 users review it.
Comment: Actually, if I find a question that was wrongly closed, I could flag it, especially if the question was closed by a moderator. It should not the user who asked the question to flag it, though.


Physically realizable quantum circuits

Question: How do we decide whether a quantum circuit can be realized physically or not ? I was wondering for physical realization of Shor's factoring algorithm using NMR ( I mean can we do it? ).
Answer: In theory, there is one easy way to decide whether a quantum circuit can be realized in principle: Can we implement a universal gate set with the system? If yes, then we can implement any circuit, if no, then we can just implement circuits with the gates we know how to implement.
So much for simple theory. The question however is much harder. First of all, we will have to worry about errors piling up and destroying our computer. So we need the theory of error correction - but the question remains the same: Can we fault tolerantly implement a universal gate set with the system? If we can, then yes, we can implement any circuit, otherwise, only the gates we know how to implement fault tolerantly.
Okay, so much for that. Now, sadly that's still not really an answer to the question of "physical realizability", it's still theory. So we have to go to the system in question and actually see whether all the gates can be implemented - and then, whether they can be implemented fault tolerantly. For most systems, this is only possible with a very small number of (logical) qubits at the moment (there are systems that can do more than NMR, I wouldn't consider it a very hot approach at the moment - then again, I'm relly not an experimentalist). Then, implementing single qubit gates is often not a big deal, multiple qubit gates, however, usually is a problem - to the point where we can't just "scale" them up to dozens or even hundreds of qubits.
To sum up: There's two sides. First, the theoretical, which is simple: Can you fault tolerantly implement the gates in the circuit? Second, the experimental, which is hard. There is really no way to say something is possible or not until everything has been checked out.
Comment: "multiple qubit gates, however, usually is a problem", could you explain it further? Many thanks!
Comment: @EdenHarder: I'm not entirely sure, what would help you. I just know that the experimental fidelities for single qubit rotations are quite good (in the range of >.9, sometimes >.99), while the fidelities for a two-qubit gate (e.g. the CNOT) are generally much smaller (more in the range of >.7). There are several reasons: a) you need to control two qubits instead of one (one is hard enough), b) the qubits must not interfer in any other way, so they will be spatially separated, but you need to act on both, c) transporting qubits to bring them near to each other is a problem.
Comment: Especially c) seems to me to prevent scaling a quantum computer. Of course, there are other schemes (dissipative, measurement based, adiabatic), which may circumvent this problem. Otherwise, please note that I'm a theorist, so I don't have all up to date numbers in my head, but I could take some time and search for some references...

Physically realizable quantum circuits


Auto populate column 2 which is also drop down based value based on user selection in column 1 drop down

Question: Can any one let me know how can i auto populate column 2 which is also a drop down based value and this column is person who needs to work on the ticket when user selects a value in column 1.
So that based on this i need to send an email to the person which is assigned.
For example
Column 1
If user selects Networks and Field services then
 - Column 2 should be "Padmini"
I am not sure how can i achieve this?
Answer: We could use SharePoint designer 2013 platform workflow to meet your requirement.
Use "If any value equals any value" action and "Set field in Current item" action as shown below:

Start options:

And Drop1 and Drop2 column are all drop down columns.
Comment: Hello Julie , Thank you so much for a simple workaround , but i have more if conditions like around 10-12 is it possible to give one by one 10 conditions?
Comment: Yes you could do this.


Sending/Receiving SMS/MMS on iPhone 4s

Question: Just got my first iPhone. Will not be using iMessages being I'm the only person in my social circle who has Apple products. Am I still able to send/receive SMS/MMS the "old" way on this phone? Also, due to the nature of my job, boss requires the phone stay off during working hours. Will I still be able to get any text messages sent to me once I'm able to turn my phone back on, even if it's a few days afterwards?
Answer: The short answer is "yes and yes". SMS/MMS work the same way on iPhones as on any other phone (including any buffering your carrier does).

Sending/Receiving SMS/MMS on iPhone 4s


Are OpenID logins compromised with the Ubuntu Forums breach?

Question: I honestly can't remember what I used to login to Ubuntu Forums, but I am quite sure it was OpenID. Should I be concerned?
Comment: OT close voter(s): This question is *definitely* on-topic; we help people with Ubuntu community resources here (["Services provided by Ubuntu"](http://askubuntu.com/help/on-topic)). Furthermore, it does *not* belong on [meta](http://meta.askubuntu.com/), which is only for questions about *Ask Ubuntu* itself (not about other Ubuntu-related sites). It might be considered a duplicate of [this earlier question](http://askubuntu.com/questions/322984/login-account-hacked-on-login-ubuntu-com) though. If we close either of these as a duplicate of the other I recommend merging their answers.
Comment: About merging answers: I had seen the other question but did not know if that applied to my case, to be honest.
Answer: Since OpenID login is always processed on the issuer side (for example, if you use OpenID you got from Launchpad, then Forums will contact Launchpad and it is Launchpad who processes your authentication), the Forums do not keep your OpenID password (they don't need it at all).
Therefore, all the attackers can get is your OpenID login, but not the password, since it's not actually there.
Also, just for completeness, according to this official announcement, only the Forums are affected, no other services are.
Comment: It's not only the case that the don't need to save it - they can't even save it as a good OpenID relying party never sees the password of the user.
Answer: From  http://openid.net/

With OpenID, your password is only given to your identity provider, and that provider then confirms your identity to the websites you visit.  Other than your provider, no website ever sees your password, so you don't need to worry about an unscrupulous or insecure website compromising your identity.

The identity provider is for instance Google and the website you visit is UF.
So yes you should be safe.
Answer: Generally speaking (to the best of my knowledge, at least) when using an Open ID account to log in, the authentication is handled purely by the external website (so for example, if I were to use Facebook to log in here, the authentication would be handled purely by Facebook and not by Ask Ubuntu). The other site only hands over a unique identifier that tells the Ubuntu Forum / Ask Ubuntu / whatever that you are you, and doesn't pass on any of your login details.
So the passwords stored (+ hashed and salted) by the Ubuntu forum would be for local accounts only (as mentioned in the "What we know" section of the current maintenance page)
Of course if you're still concerned about it, it wouldn't hurt to change your passwords - and for peace of mind it would probably be a good idea to do so anyway - but as far as I am aware unless the service you used to authenticate your Open ID was breached (Google, Facebook, etc) there shouldn't be too much cause to worry.
See this page on the OpenID website for further details.
Answer: If you really used OpenID: No.
The login process is executed between your OpenID provider and you.
The services that allows you to use OpenID doesn't even see your password! There is no possibility how ubuntuforums could have stored your password.
OpenID resources
The following resources might help you to understand how OpenID works.

A YouTube video
Wikipedia
A lot of content from Google about OpenID (The image is very good)


How would 2 JWSTs make stereo pictures?

Question: Could 2 JWST be launched in opposite directions to provide stereo vision? Would a stereo picture provide any benefit?

https://space.stackexchange.com/a/35402/18879
Related: How will JWST manage solar pressure effects to maintain attitude and station keep it's unstable orbit?
Comment: I would like to write an answer, but I am afraid that you will soon edit the question and change it to something completely different. Also, your title is constricting, it requires answers to be "launched in opposite directions". Can you loosen that to match the body of your question?
Answer: Let's think about what stereo pictures give us scientifically rather than aesthetically. It's information about depth. How far something is away.
Why scientifically? Because while bass players and astrophysicists like Brian May† can occasionally also be rich, they usually don't so many billions of dollars that they would need to count them on both hands to build a seconds JWST for aesthetic reasons.
†https://www.londonstereo.com/ See also Brian May Stereoscopy #1 - An introduction, Wired's This stunning book from Brian May lets you see the Moon in 3D and especially the BBC's The Space Race like you've Never Seen it Before.
For the part of the universe that is beyond 1 AU from the Sun, i.e. nearly all of it, one can simply let the Earth orbit the Sun and take photos several months apart to produce a stereoscopic view. This provides a method to measure distance using the resulting parallax.
For things like the Sun itself, the STEREO pair of spacecraft have been used to image the Sun from two different directions at the same time which is important for phenomenon which are rapidly changing and so one can't wait for the Sun to rotate around, or for the Earth to revolve around it, in order to get multiple views from Earth.
So the only scientific advantage to having a pair of JWST-like telescopes in different orbits to produce simultaneous views would for there to be a phenomenon of unknown distance, or requiring two different views to gain more depth information.
Very few things fall into that category. Right now I can not think of any for which a pair of JWSTs in different orbits would yield definitive and valuable scientific information.
But if there were some, what kinds of orbits would be possible?
A pair of libration points Sun-Earth L1 and L2
Separation: 3 million kilometers.
JWST is destined for Sun-Earth L2. An obvious choice for its companion would be Sun-Earth L1. This puts them similar distance from Earth in fairly similar orbits, requiring fairly similar station-keeping strategies and delta-v budgets and allowing for fairly similar communications bandwidths and powers.
You will have to of course do some engineering. The communications antennas will point in the same general direction as the Sun at L2, but the opposite direction for L1 just for example.
Also, thermal radiation from the hot Earth (and less so by the Moon) will now not be blocked by the heat shield. That could potentially be an unacceptable heat load, and is certainly a pointing problem. I think pointing JWST anywhere near the Earth will be quite problematic, but expanding on that would be a separate question.
fwiw GAIA is already at Sun-Earth L2. What are reasons to put Gaia space telescope into L2 Lagrangian point of Sun-Earth system?
A pair of libration points Sun-Earth L4 and L5
Separation: 260 million kilometers.
Or you could move them to Sun-Earth L4 and L5 at +/- 60 degrees. The big advantage is a baseline now almost 100x larger than for L1/L2. Another advantage is that the Earth's heat load at 100x farther is probably inconsequential.
However there are several problems. The path losses (i.e. 1/r^2) will be 10,000 times worse for radio, so the JWST may need a higher power transmitter to provide sufficient bandwidth at its currently approved (and fundable) downlink schedule.
Also, since both telescopes have to avoid much of the Sky avoiding getting close even to the Sunward hemisphere, it's possible there's little sky available that a JWST at L4 and at L5 could view simultaneously.

Parenthetically, STEREO A has passed near Sun-Earth L4 but kept on going, and STEREO B and the Spitzer Space Telescope have likewise both passed near L5; but none of them actually slowed in order to take up position in those areas. See [this answer](https://space.stackexchange.com/a/21222/121020 and watch the potentially helpful but slightly confusing video:
Comment: Yes, If we had 2 JWSTs, I can't think of a worse use for them than having both image the same far away object at the same time. Well... I *can* think of worse uses, but not ones involving legitimate astronomical objectives.
Comment: @Ingolifs if you want to snark about the question, do it up there. Here I've *explicitly constrained* the possible applications to either distance metrology or dual views that would have scientific value. If none exited, you wouldn't do this. I've also pointed out in the answer that there already is a space telescope at L2. It would make an awkward pair, but when JWST is up and running, I wonder if a distance to a near-Earth comet or asteroid could be measured stereoscopically, just once, just to say it's been done.

How would 2 JWSTs make stereo pictures?


Is Absurdism Compatible with Judaism?

Question: I have been getting into the works of the French philosopher Albert Camus, who is the face of the philosophical idea of "The Absurd" or "Absurdism". I was wondering if this philosophy is compatible with Judaism, or if some components of it at least.
Through his works, Camus conveys that the universe is a chaotic and indifferent place in which we humans will forever struggle to find meaning in/ will not ever fully comprehend. I think this can somewhat align with Judaism as there is an acknowledgment that humans don't fully understand the universe.
I am just a mere beginner delving into this philosophy and I appreciate any response!
Comment: Welcome to MiYodeya and thanks for this first question. Since MY is different from other sites you might be used to, see [here](https://judaism.meta.stackexchange.com/a/3887/11501) for a guide which might help understand the site. Great to have you learn with us!
Answer: Generally, the core tenant of absurdism is not just that humans struggle to find the meaning of the world, but that there is no meaning, that the world is absurd and undirected, Camus has said "The absurd is born of this confrontation between the human need and the unreasonable silence of the world. This must not be forgotten.
This must be clung to because the whole consequence of a life can depend on it. The irrational, the human nostalgia, and the absurd that is born of their encounter, these are the three characters in the drama that must necessarily end with all the logic of which an existence is capable." Essentially the position being that, mankind has formed a (pseudo) system of logic out of a completely irrational world, as opposed to Jewish teachings that the world is imbued with a rationality and a systematic completeness by God. While every philosopher has different views, generally absurdism, which teaches that the world is absurd, ie. that the world lacks meaning or a higher purpose and is not fully intelligible by reason,  is not compatible with Judaism, which is juxtaposed by a strong belief in rationality throughout the universe, and a clear purpose for mankind.
Its also worth noting that absurdism is not compatible with almost any philosophical positions, or really any deep philosophy (ie. Logical deduction) as a practice, which relies upon reason as a system. Camus famously said that he did not consider himself a philosopher because he did "not believe sufficiently in reason to believe in a system."
If you would like to read some philosophers that are more compatible with Judaism, or even those which are not but at least give you more to contemplate, please let me know.
Comment: Thank you for the detailed and clear response! I would love to get more recommendations to look into, as this topic really does incite my interest.
Comment: @H.B.S. I recommend "Duties of the Heart" by Bachya ibn Pequda for a very strongly Jewish philosophical treatise. Sefer HaIkkarim is also good in this regard but it is rather technical, it might not be what you are looking for. Everything by Rabbi Dr. Dovid Gottlieb is very good, he has a few books. The Brothers Karamazov/Book V/Chapter 4 by Dostoevsky https://en.wikisource.org/wiki/The_Brothers_Karamazov/Book_V/Chapter_4 is very popular amongst (non Jewish) philosophers for the interesting question it asks, it is up to you to determine your thoughts on the matter.
Comment: @H.B.S. Rabbi Dr. Dovid Gottlieb has this treatise avaiable for free, it is a collection of his lectures, https://www.dovidgottlieb.com/works/RabbiGottliebLivingUpToTheTruth.pdf
If it resonates with you, then you will probably like his bonafide books even better. He has also has many (many) lectures available on TorahAnytime and other sites.

Is Absurdism Compatible with Judaism?


Does Angular (or other frontend framework with auto UI update) break Single Source Of Truth since using function within template should be avoid?

Question: I know when building an Angular app (or other frontend framework with auto UI update by change detection), using function in a template is not recommended since it will result in the function being called every time when change detection runs. This means if we want to display a value derived from another value, we have to explicitly create another field to store that derived value. For example, if I want to display a temperature in both C and F and my model only stores the value of C, I have to compute the value of F from C, then store in a separate field, and display both fields in the template. Dose this considered breaking Single Source Of Truth? Are we essentially trading for performance, in the cost of having code smell?
Answer: Yes, thats how it is.
Software Development is the Art of Trade-Offs.
You could display the content of variables, and update those by hooking into the life cycle of the framework and there do a check if an update is necessary and then call your update methods.
If your method is a pure function you could easily implement a memorisation (store input/output combinations and reuse them instead of recalculating the values each time).
But its a trade-off.
You can choose between a not optimal performance, a code smell or complicated code.
Therefore it totally depends on the context which one is the "best" solution.


Is it ok to upload hair pictures and videos only?

Question: I make hair related content, where i share haircare/ growth tips for which i have to show my hair only so that audience can rely on my techniques and sometimes i have to show tutorials for certain hairstyles.
But i dont show my face, so is it still haram? Because as long as I know hair itself is not a sexual part, and i am not showing my face , so nobody can have a slightest image of who i am.
Because i am thinking to expand it as my hair brand but i am very confused that should I continue or not
Answer: NO it is haram. The (awrah) of a female is all of her body except her face and hands up to the wrist. So it is not allowed to show or post other parts online. This parts is what Allah ordered to hide, so our job is to obey Allah and not make our own classifications for whether it is sexual or not. Prophet Muhammad says what means: you will never leave something for the sake of Allah, but Allah will give you something better instead of it, so you should stop doing that. You can find alternative ways to advertise for your work.


Is membership by relationship charged for?

Question: I've created an organisation membership and set a cost. I've also made a relationship so employees inherit that relationship. I can't find out anywhere if someone inherits that membership are they also charged?
Answer: As far as I'm aware only the organisation is charged but the employees are able to receive the benefits of membership.  The employees don't get charged separately for that membership.
You can find more information about membership in the book:
Defining memberships
Comment: agree. the cost is only associated with the parent membership


Is the mechanism behind osmosis attraction of water molecules or pressure differences?

Question: I am trying to get an understanding of the physical mechanics behind osmosis. About half the sources I have found say that it is due to differences in pressure, but some say that it is due to the attraction between water molecules. Is there more evidence of one than the other or is this a widely debated topic among scientists? If it is due to pressure differences then would it still work with a solute that is heavier than water? Why?
Answer: Random walks of the solvent have the net effect that more solvent molecules go to the concentrated solution than the other way around (diffusion). This dilutes the concentrated solution, thereby increasing the number of microstates.
The process continues until the pressure difference is so high that the flow due to pressure balances transport due to diffusion.


Efficiently reversing the triangle inequality with additional information

Question: Suppose $f$ and $g$ are bounded functions, having whatever niceness properties you want, on some space of finite measure. Assume they are normalized so that $\int |f|^2=\int|g|^2=1$. I am looking for sufficient conditions so that $$\int|f+g|\geq c(\int|f|+\int|g|)$$ for some positive $c$ bounded away from zero. The sort of thing I have in mind is, say, control over $\int |f|^p|g|^p$ for $p>1$, which I interpret as meaning $f$ and $g$ cannot be too correlated. Are there instances where this sort of thing can be done? If not, what do counterexamples look like?
Comment: I would think that $f = -g$ is a counter example unless you include positivity in you niceness conditions.
Comment: This is asking when the signs of f and g are the same a lot - ie $\int_A |f+g| = \int_A |f|+ |g|$ where $A$ is the set on which $f$ and $g$ have the same sign. So you're asking for when $\int_A |f|$ and $\int_A |g|$ are large compared to $\int |f|$ and $\int |g|$
Comment: Well, I suppose I am thinking of $f$ and $g$ as being complex valued. I am thinking that for them to interact destructively, they have to have similar arguments and order of magnitudes. The point of the $L^p$ estimate is to try to prohibit the order of magnitudes from lining up too much.
Answer: You definitely need certain "niceness" assumptions. For instance, you can look at $f$ and $g$ on $[0,1]$ with
$$f(x)=\begin{cases} N & \text{ if }0\leq x\leq \frac{1}{2N^2}\\ \frac{1}{\sqrt{2}} &\text{ otherwise}\end{cases}$$
and
$$g(x)=\begin{cases} N & \text{ if }1-\frac{1}{2N^2}\leq x\leq 1\\ \frac{-1}{\sqrt{2}} &\text{ otherwise}.\end{cases}$$
Both of these functions have $L^2$ norm about 1, $L^1$ norm about $1/\sqrt 2$, and $\int|f+g|$ is about $1/N$. Because their spikes are disjointly supported,
$$\int |f(x)|^p|g(x)|^p\leq \frac{1}{2^p}+N^{p-2}$$ which is pretty small. By comparison, if $f$ and $g$ had the same spikes, then this would be about$N^{2p-2}$ in magnitude.
Answer: Let $(\Omega,\mu)$ be a measure space and let $f,g:\Omega\mapsto\mathbb{R}$ be two bounded real valued functions defined on the space $\Omega$ with $\mu(\Omega)<+\infty$. Since $f$ and $g$ are bounded then there exists $M,N\in\mathbb{R}$ such that $|f|\leqslant M$ and $|g|\leqslant N$ on $\Omega$. Therefore $$\int_{\Omega}|f|+|g|\,d\mu\leqslant \int_{\Omega}(M+N)\,d\mu=(M+N)\mu(\Omega)<+\infty$$
On the other hand from triangle inequality we have
$$\int_{\Omega}|f+g|\,d\mu\leqslant\int_{\Omega}|f|\,d\mu+\int_{\Omega}|g|\,d\mu$$
Therefore a sufficient condition would be:
There exists some positive constant $c\leqslant 1$ such that $|f+g|\geqslant c(M+N)$.


How to get to know the XML file and its path for that template Path Hint in Magento 2

Question: As we can enable template path hints in settings along with blocks but there is no option to show from which xml file it is coming in the frontend. How should I know which xml file to write to move, remove and add template to that location. Sometimes it become very difficult to find the file related to that template path because there are so much files presented in the folder.
Comment: When i do that sometimes there are too much files then it create a mess to found the actual file.
Comment: You can search by the `phtml` path in your project, in your ide, ssh, local project
Answer: Personally I download a copy of the site, then search for tags within the code (often "class" html tags)  You can usually quickly work back from there to find the CSS, .phtml and .xml
I use fileseek as it is free to do this
Comment: There are too much files how to choose the right one. Sometimes on phtml file is added in to number of xml files. How to choose the right one to save time.


What is the opposite of `git diff HEAD^`?

Question: In git, I can specify the previous revision by saying HEAD^ or HEAD~1. What about going the other way? Suppose I'm on revision X, and I do git checkout X^. How do I go back?
Something like git checkout X+?
Comment: Do you really want the opposite of HEAD^ or just a way to "go back"? (You can go back to previous HEADs with HEAD@{1}.)
Answer: You can't really do precisely that. History in git is a directed acyclic graph - each commit contains references to its parents, but parents don't have references to their children.
The problem here should become obvious when you think about a commit you created multiple branches from. Which "next commit" do you mean? With parents, you can number off (a normal merge commit has a first and second parent), but how do you do that with children? Even if you know what branch you're trying to be on (e.g. you've checked out master~4 and now you want to look at master~3) it's not well-defined - you could be in a situation like this:
- X (HEAD) - o - o - o - Y (master)
   \                    /
    o - o - o ----------

That said, in simple cases, you could do something like this:
git checkout $(git rev-list HEAD..master | tail -n 1)

Clearly that'll work fine with linear history. With merges... rev-list works from present to past in the history, following it backward. I believe it follows the first parent first, so the thing printed last will be the commit after HEAD found by following all last parents.
Edit: That does assume that you know which branch you want to move forward toward. If you don't... well, you're pretty much stuck looking on all refs for commits which have the current HEAD as parent - probably grepping the output of git rev-parse:
git rev-list --all --children | grep ^$(git rev-parse HEAD)

Then grab the other SHA1 from the line (use awk, whatever). You'll have to manually inspect or make an arbitrary choice if there are multiple results though...
Comment: Technically, the same issue exists the other way, i.e. if head is at point Y, which path does `HEAD^` follow back? Both branches may have been master... I think the other answer is probably more accurate, about each commit storing parent commit, and `HEAD^` uses that.
Answer: I don't think this is possible, since a Git commit only stores its parent commit, but not its children.
Imagine a commit would store its children. What would happen if you would create several branches off this commit, so multiple commits have this commit as parent? What would then be "HEAD+"? This is ambiguous and wrong.
Speaking in what I know from data structures:
Git stores history as a single-linked list, whereas you operation would need a doubly-linked list.
Comment: It's a little worse than that - see my answer about the ambiguity even if parents knew about children.
Answer: As far as I can tell there's no symbolic way to refer to the children of a commit.
The best I can give you just now is the --children option of git rev-list. Here I ask for the four most recent commits to be pretty-printed, plus information on their children. Note that on the "commit" line of each entry (other than the most recent) there is an extra commit number, which specifies the child of that node. You could grab that either manually or through some shell scripting to get to the child.
$ git rev-list --children --pretty HEAD~3...

commit 20dba296ad1d48ec90f9319e2c13b245e849f698
Author: Somebody <____@____.net>
Date:   Thu May 6 19:10:38 2010 -0400

    Support for complex trig/pow.

commit 9d42b5bac1721a847a39c25672e577c7101c8ff0 20dba296ad1d48ec90f9319e2c13b245e849f698
Author: Somebody <____@____.net>
Date:   Wed May 5 21:55:07 2010 -0400

    Fix doc formatting warning.

commit 72bed3baa9df71cb224dfa8388b5969d50f5567c 9d42b5bac1721a847a39c25672e577c7101c8ff0
Merge: b8244cb61491c9cdb83d36e57f8eb49773e44f6b 899c3dd3f9f419f200b84ca0abe59d7ac3d5bb53
Author: Somebody <____@____.net>
Date:   Wed May 5 21:54:59 2010 -0400

    Merge branch 'master'

commit 899c3dd3f9f419f200b84ca0abe59d7ac3d5bb53 72bed3baa9df71cb224dfa8388b5969d50f5567c
Author: Somebody <____@____.net>
Date:   Wed May 5 21:19:11 2010 -0400

    Fix link

Answer: As a pragmatic answer, just use git checkout - to go back to the previous position, 90% of the times it will be where you want to be.
This is not looking for a child and traversing the tree in reverse order or anything like that. The syntax is based on the popular cd -, and similarly, git checkout - is not "going back one place" as cd .. does.  It just puts you back on the last known place where you were before.


Use cases for calibrated IV surfaces

Question: What are common applications of a calibrated options IV surface when trading vanilla options only?
Thank you!
Answer: Here are a few use cases.

If you have only a small number of quotes, then you can use a model to imply option prices where you don't have a market.
You want to create a smooth interpolation for other purposes, like calculating the local vol surface using Dupire's formula.
Converting the vol surface into a smaller number of points - i.e. your model parameters - then you can calibrate them each day and look at the time series. This is often a far easier way to look at a time series of vol surfaces - what you're doing is decreasing the dimensionality of the data for the purposes of understanding/visualisation.
They can also be a way of understanding your risk and attributing PnL.
a. For understanding your risk, you can fit a model, and then look at the change in value of your portfolio as you bump model params.
b. For attributing PnL, you can do the same as above, except instead of bumping for the understanding of moves, you move the params one by one (or one at a time, depending on how you want to think about the cross greeks) to get you from the params at the beginning of the period to those at the end, looking at the incremental PnL change as you move them.

Now, all of the above come with the very important caveat that you are projecting the world onto your model. There are a several impacts of this - for example:

Inbetween points of market data, you are interpolating. Depending on the assumptions of your model, this will force various dynamics. A simple example is using a cubic spline where you have constraints on your derivatives (i.e. keeping the first derivative continuous, etc.)
Outside of your calibration points you're extrapolating - this is where your model assumptions are really important, especially in cases where the price of the derivative you're looking to value strongly depend on the wings (i.e. var/vol swaps in equities, CMS in rates)
everywhere, the assumptions of the second derivative have strong impacts on the calculated local vol using Dupire's formula.
Comment: Thank you for the insightful answer. Is there any use case where it is used for static arbitrage? I guess that static arbitrage is directly detected using bid/ask book rather than IV parametrization. Since it is the presence of arbitrageurs that justifies that the surface should be arbitrage free, this confuses me in what we define as arbitrage in terms of the volatility surface (not considering that we buy at ask and sell at bid for e.g. butterfly arbitrage). I will open another question.
Comment: Excellent! Much appreciated. Thank you all for your insights.
Answer: A common use case is in FX, where the market convention is to quote a grid of maturities and deltas (typically 1W, 2W, 1M, 2M, 3M, ...) and (10, 25, 50, 75, 90) delta but the options that you hold in your portfolio will have strikes and maturity dates that don't line up with this grid. If you want to price these options you need a calibrated volatility surface to interpolate them.
Answer: To calculate theoretical option prices using a smoothed IV surface. Because the market observed option prices can deviate from theoretical prices especially for far ITM and OTM options. This creates arbitrage scenarios.

Use cases for calibrated IV surfaces


Adding jQuery Timeline to Drupal

Question: I have found this awesome jQuery Timelinr that I have customized for my Drupal site but am now at a loss at how to insert it. It is only going to be on one page. Does it need to be in a block? Do I have to make a custom module? Any assistance would be greatly appreciated!
Answer: There are many ways to do it. Easy one is to add it on your theme's .info file: scripts[] = js/your_jquery_plugin.js
But then its everywhere.
You can add it in a block. Check that your text-filter is set to PHP (May need to be active in the modules: PHP filter). Then add drupal_add_js()
Comment: Thank you so much for your reply! I went ahead and used the drupal_add_js() in a page as suggested above. I am still having trouble with the formatting of the function. How do I drupalize it?

$(function(){
   $().timelinr({
    orientation: 'vertical',
    issuesSpeed: 300,
    datesSpeed: 100,
    issuesSpeed: 500,
    arrowKeys: 'true',
    startAt: 3
   })
  });
Comment: your $().timelinr(){}; lacks where it should be applied. $("#IDsomething").timelinr(){}

ps: you can upvote the answers you like. Arrow up.
Comment: Sorry I have been MIA. It's finals week. That bit of code above works without anything on a regular page, just not in drupal. I tried putting the timeline div name (as that is where it should be applied) but that still does not work. The jquery is loading and I put all the necessary markup in the body but it is still a no go. Anything else you could suggest?
Answer: If it's only o one page you can also create a plane new page set the text filter to PHP and add the drupal_add_js() code.
See here for some hints about integrating custom jQuery code into Drupal.
Comment: Thanks for your help! I used your suggestion but am still having trouble formatting the function (see below). Let me know if you have any ideas on that. Thanks!
Answer: Did you resolve it meanwhile? If not, I suppose it is because of jquery-version conflicts. The Drupal built-in version is NOT new enough for this script; even the jQuery Update module does not bring the newest version. I had the same problem when trying to implement another jQuery script. I resolved it by removing the built-in jQuery and adding the new one. I did that in the page template. I know, it is not recommended.

Adding jQuery Timeline to Drupal


Why is the current unrest in the Arab world called the "Arab Spring"?

Question: Does spring in "Arab Spring" refer to the season - or something else?
Answer: According to this news article, the term is a reference to older revolutions:

Talk of an Arab revolution gave way to the adoption of the term "Arab spring" to describe developments. This has echoes of the "Prague spring" and other eruptions in Eastern Europe, which did not succeed in throwing off the yolk [sic] of Soviet domination until the collapse of the USSR.

The Prague Spring was a revolution in Czechoslovakia, which began in January of 1968. It was "Spring" because it included a series of reforms (where Spring is known as the season of new beginnings). The name of this revolution has also influenced the naming of others:

A decade later, a period of Chinese political liberalization became known as the Beijing Spring. It also partly influenced the Croatian Spring in Yugoslavia.[68] In a 1993 Czech survey, 60% of those surveyed had a personal memory linked to the Prague Spring while another 30% were familiar with the events in another form.[69]The Vatican' s semi-official newspaper L'Osservatore Romano referred to the regime changes taking place in North Africa in 2011 as "Arab Spring"
Comment: That's it. It all goes back to the "Prague Spring". Sadly, that one ended rather badly...
Answer: In this case Winter (or perhaps ice and snow) is being used implicity as a metaphor for a society ruled by opression with little freedom. Thus "Spring" is indicating that the opression is melting away like the ice thawing in Spring.
As simchona correctly indicates, the metaphor was first used to describe the brief period of reforms tried out by Czechoslovakia. It was particularly apt in their case, because, like the real season, it came for a while then went away (thanks to Soviet tanks). Note that they even had their own self-immolating martyr.
Hopefully in the Arab's case, the Arab Spring will instead move on to a long summer. Inshallah
Comment: @Louis: [wikipedia](http://en.wikipedia.org/wiki/Prague_Spring) isn't enough?
Comment: can you cite a reference for your assertion?


How do I create an oblong torus with a constant thickness?

Question: I've tried making a torus and stretching it and making an oval curve and beveling a circle on it, but with both methods the torus ends up getting thicker on the sides that are stretched out. Is there any way to keep the minor radius constant along the whole shape?
Comment: Create a mesh circle. Tab to edit mode and stretch along one axis. Tab back to object mode. Convert to curve `Alt` `C` > `C`. Bevel it. Convert back to mesh `Alt` `C` > `M`. Neither Bezier nor Nurbs curves can exactly represent elliptical shapes, not even circles. They approximate circles fairly well, but with ellipses, their shortcomings in this department become painfully apparent.
Comment: @SixthOfFour you should write that as an answer (preferably with screenshots).
Comment: @AWildRolandiXor The reason I wrote it as a comment, is that I'm not at my blending computer, thus I can't make any screenshots. I'll post an answer though, and add screenshots later.
Comment: Yeah, in cases where your comment is an answer it's best to add the answer (unless you think the question might be off topic, but you can provide a solution in a comment while flagging/voting to close). You can always edit answers later to provide improvements, etc.
Answer: If you stretch a torus, both the major and the minor radii will be stretched, so the effect you see is perfectly normal. There may be some way to remedy that, but I haven't found it. I have come up with some workarounds though.

Method 1
Add a mesh circle.
Tab into Edit mode1.
Scale it along one axis, SX or SY.
Tab back to Object mode.
Convert the circle, which should now be an ellipse, to a curve AltC > C.
Put a bevel on it. If you want a circular tube, you needn't use a bevel object. Just set the bevel depth and resolution to whatever rocks your boat and set Fill to Full.
When you're happy with it, convert it back to a mesh AltC > M.
Unfortunately I haven't been able to find out how to include the menus when I take screenshots, so this doesn't show the conversion between mesh and curve and back.

The reason I don't use a curve directly, is that neither Bezier nor Nurbs curves represent elliptical object very well. They approximate circles acceptably, but with ellipses they fail miserably unless you give them a ridiculous amount of vertices.

Method 2
If you have the Extra Objects addon installed and activated, you can use XYZ Math surface to create a torus object of practically any shape.
To enable this addon, go to User Preferences CtrlAltU > Add-ons > Add Mesh > Add Mesh: Extra Objects.

Add > Mesh > Math Function > XYZ Math Surface
For an elliptical torus with a major axis of 3, a minor axis of 1 and a circular tube with a radius of 0.25
X equation:
(3+.25*cos(u))*cos(v)
Y equation:
(1+.25*cos(u))*sin(v)
Z equation:
.25*sin(u)
U min and V min: 0
U max and V max: 2*pi
U wrap, V wrap and Close V enabled.

The normals will be pointing inwards, so you'll need to flip them. Tab into Edit mode and hit CtrlN to recalculate them to point outwards.

Method 3
Here's a third method that I discovered today, when reading this question. It uses the Skin modifier, which is something I've never used before. This seems to be the simplest method, and very straightforward, and that's the reason I'm making this late addition.
Add a mesh circle.
Tab into Edit mode1.
Scale it along one axis, SX or SY.
Tab back to Object mode.

Add a Skin modifier.

Add a Subdivision Surface modifier. As pointed out by PGmath in a comment to this answer, the Catmull-Clark algorithm doesn't produce a perfect circle, and depending on your need for accuracy in the shape of the skin, you may want to consider using one of the first two methods instead.

The radius of the skin can be scaled. Make sure the Skin modifier is still in the modifier stack, i.e. do not apply it.
Tab into Edit mode.
Make sure everything is selected (A once or twice).
Press CtrlA and then drag the mouse or use the arrow keys on your keyboard until you're happy with the thickness. Enter or left mouse button to confirm.

1Scaling in Edit mode is essentially the same as scaling in Object mode and then applying the scale.
Comment: BTW, you can use alt+shift+S (I think that's the right combo, if not somebody can correct me) to change the skin radius.  And also, *technically* Catmul-Clark subdivision doesn't converge to a circle (off the top of my head I think it converges to a cubic polynomial), so the cross section won't be a perfect circle.
Comment: @PGmath I know it doesn't make a perfect circle, and the first two methods are more accurate. I still think this third method is very usable though, and the cross section is closer to a circle than a Bézier or Nurbs  scaled on one axis would be to an ellipse.
Comment: @PGmath I just consulted the Blender Wiki on the [Skin modifier](http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.64/Skin_Modifier), and the radius can be adjusted with Ctrl+A in Edit mode. I'm a little busy right now, but I'll update my answer when I have a chance. Thanks for pointing it out.
Answer: Methods 1 and 3 in the other answer are definitely good, and worthy of an upvote. However, method 2 leaves a little to be desired. The standard equations for a circular torus won't yield an elliptic torus with constant thickness. It will be more visible the more eccentric the ellipse gets.

I'm working on my first ever Blender add-on, which (if all goes well) will add tori of different configurations. Currently I have the elliptic torus in working order, and I'm happy to share it, if anyone would be interested. It's available from my GitHub repo Tori. Just click Clone or download and save it to your harddrive.
To install it, open up Blender, hit CtrlAltU to open up User Preferences.
Click Add-ons, then Install Add-on from File and select the file you downloaded (Tori-master.zip).

You should now see the following.

Click the chek box next to Add Mesh: Tori, and the add-on should be working. If you want to make it survive restarts, also click the Save User Settings button.
There should now be an Elliptic Torus entry on the Add -> Mesh menu.

The options are as follows
Major Semi-Radius is half the size of the major axis of the ellipse.
Minor Semi-Radius is half the size of the major axis of the ellipse.
Tube Radius is the radius of the cross-section.
Ellipse Segments is the number of segements into which the ellipse is divided.
Tube Segments is the number of segements into which the cross-section is divided.

As this add-on stands right now, it's not that useful, as this can be easily achieved by other means. However, I do have some plans for tori with configurations that none of the available torus add-ons handle, and this is just the initial setup and part of my learning process. Specifically I'm aiming to get an elliptic torus with constant thickness but parallel cross-sections working.


How to get exact position of a ruler guide in Photoshop?

Question: There is a horizontal ruler guide set somewhere in the middle of an existing Photoshop CS5 document. How to get its exact position (number of pixels from the top) so I can create another guide 100px away from it?
Answer: In the menu choose "View > New Guide...", this will ask you for Horizontal or Vertical Orientation of the line you will make. Position being the location of the line on the paper (4th geometrical quadrant)
Comment: Bad because it doesn't answer the question, good because it solved the problem I ended up here trying to solve (placing a guide in a particular location). Voted up because I bet most people would be happy to just put the guide where they want it, and the real answer is lame (hover and watch info).
Comment: The answers above is less more effective than this one.
Comment: The question is how to determine the value to specify as the location of the line.
Comment: This answer is how to create a new guideline, not how to get the position of an existing guideline!
Comment: Sorry @Goowik, I was answering the second part of his question, about setting it 100px away once he knows the position he wants, rather than move it by hand and missing by a few pixels. I don't like to edit my answer after it has been read, so I left it as is, sorry if it confuses you.
Comment: @orosznyet: What answers above and what does less more effective mean?
Answer: I only have the CS4 version. In it the way I would try to determine this would be to use the cursor X & Y position displayed in the INFO tab of the Info window (F8 key). This displays the current location of the mouse cursor measured relative to the active document's top-left corner. With that visible all you need to do is move the mouse cursor so it's on top of the ruler guide and look at the X or Y value displayed. Zooming in on the image can make positioning the cursor precisely easier, so can enabling the Precise option in Cursor Preferences (not shown in screenshot below).
Alternatively, you may be able to read the position off the regular horizontal or vertical ruler that can be made to display (Ctrl-R or Cmd-R) on the edges of an image's window.
Below you can see there's a ruler guide (the light blue vertical line) with the mouse cursor directly on top of it. As you can also see, "950" is what is being displayed for the X coordinate in the INFO pane of the floating window over on the right -- which is exactly the position specified when the guide line was created for use in this example.
Answer: Make sure the Info panel is visible, then start moving the old guide (Ctrl or Cmd and drag).
You should see something like this:

The ΔX: and ΔY: fields (upper right) will show the offset from the original position.
The X: and Y: fields (lower left) will show the absolute position.

Drag back until the offset is zero, which means the guide is in its original position, then read the absolute position off of the corresponding X: or Y: field.  If you wish to read the position in pixels you will need to set that measurement section of the Info panel to pixels, which is done by clicking the + symbol at the left side.  Once you have read the position you can press Esc to cancel the move, which will make sure that you don't accidentally move the guide by a pixel or two as you release.
By the way you may find use in the GuideGuide plugin.
Answer: This script will get you a list of all guides in the active document:
function getGuides(doc) {
    var i, l;
    var g, d;
    var guides = [[],[]];

    for (i=0,l=doc.guides.length; i<l; i++) {
        g = doc.guides[i];
        d = (g.direction === Direction.HORIZONTAL) ? 0 : 1;
        guides[d].push(parseFloat(g.coordinate)+0);
    }
    return guides;
}

function listGuides(doc) {
    var report = "Guides in " + doc.name;

    var guides = getGuides(doc);
    var directions = ["Horizontal", "Vertical"];
    var units = (doc.guides.length) ?  doc.guides[0].coordinate.toString().split(" ")[1] : "px";

    var i, j, l;
    var d;

    for (d=0; d<2; d++) {
        report += "\n\n" + directions[d] + ":\n";
        if (guides[d].length) {
            guides[d].sort(function(a,b){return a-b;});
            for (i=0,l=guides[d].length; i<l; i++) {
                report += "\n" + (i+1) + ") " + guides[d][i] + " " + units;
            }
        } else {
            report += "\nNone";
        }
    }
    return report;
}

//Dispatch
if (BridgeTalk.appName === "photoshop") {
    alert(listGuides(app.activeDocument));
}

Comment: Very useful! To run this, save it as a .js file then use File > Scripts > Browse... to select the file.
Comment: I just tried to use this script and got the following errors: `Script Alert: undefined`, followed by `Error 21: undefined is not an object. Line 6 -> for (i=0,I=doc.guides.length; i<I; i++){` (Windows 10, Photoshop CS2). Any suggestions?
Answer: on Adobe Creative Cloud (2017), when you drag and make the ruler guide, don't let go the left mouse button.  It will show the current coordination of x-axis or y-axis.
Comment: Where the current coordinate will be shown? As a tooltip? Or at bottom where the status bar is?


Shoulder Steak vs London Broil

Question: I bought a piece of shoulder steak. Can I cook it like a london broil - marinating it and then broiling for around fifteen minutes?
Answer: Shoulder steak & London broil are often used interchangeably. I won't bother with technical/pedantic differences, as practically speaking, the exact same cut of meat may be labeled "shoulder steak" at one grocer and "London broil" at another.
So yes, your shoulder steak is what you are used to seeing as London broil. So you can cook it exactly the same.
Comment: London broil is traditionally _flank_ steak, not shoulder. Of course, other cuts are sometimes substituted, but it would be definitely wrong to claim that London broil is in fact synonymous with shoulder steak. I wouldn't even go so far as to say the terms are _often_ used interchangeably, though I'm sure it does happen. See e.g. https://en.wikipedia.org/wiki/London_broil
Answer:
Can I cook it like a london broil - marinating it and then broiling for around fifteen minutes?

London broil is traditionally prepared using flank steak, but the technique works well for other lean/tough cuts. Your shoulder steak may have more connective tissue than one would typically find in a flank or skirt steak, but not so much that most would find it a problem.
Marinating and grilling or broiling along the lines of London broil will work fine, as long as you're prepared to accept the extra gristle. Otherwise, consider a longer braising approach to break down the connective tissue.
For more information, see e.g.:
Shoulder Steak
What is Shoulder Steak? What is it Good For? How do You Cook it?
Which cuts of beef are suitable for slow cooking methods?

Shoulder Steak vs London Broil


Calculate regional slope from DEM

Question: I need to calculate regional slope for a coastline using a ~500 meter DEM covering a coastal plain and continental shelf where the slope for each grid cell is calculated by defining elevation extremes within a 10 km radius for each individual grid cell. Normally slope is calculated using a 3x3 window. How do I increase that window? Is there a way to do this in ArcMap?
Answer: Obtain the elevation extremes by means of a Focal maximum and Focal minimum using a circular 10-km neighborhood.  Use map algebra operations to complete the work.  (Since you haven't described how the extremes will be used to estimate a slope, I cannot provide details.)

If what you really want is a generalization of the 3 x 3 approach (which is not based on the extremes), it can be done by computing focal means of the original DEMs, their squares, and their product, and then applying standard formulas for ordinary least squares regression to estimate the parameters of the least-squares plane that is fit to each neighborhood.  From those parameters you can easily obtain the mean height, slope, and aspect.  Follow the instructions at https://stats.stackexchange.com/a/197788/919 or emulate the R code at the end of that post.
(Converting the DEM to points to carry out either of these calculations would be ridiculously inefficient and complicated.)
Answer: The steps are, requires scripting:
i=0

Convert DEM to points
Select all of them within 10 km radius from point i
Interpolate surface using trend
Calculate slope of result.
Use raster statistics to define mean slope (in theory it must be the same everywhere, but points on the edge are an issue). This is why statistic will do.
Record value in point table

i+=1 and goto step 2. Stop when no points left.

Calculate regional slope from DEM


Can we have a photon at rest?

Question: Theoretically, Photons don't have rest mass but they behave as material particles in many cases.
But is it possible to stop a photon without destroying it ie. Can we slow it down so much to make it almost at rest and if not Why?
Comment: They look like duplicates to me. If you can clarify exactly what you're asking and why the linked question doesn't answer it then I'd be happy to reopen. Note that if you're asking about the photon speed in vacuum then that is always $c$ for all observers. Photon speed only varies in a medium.
Comment: @johnrennie They are different and just look apparently same
Comment: @JohnRennie I am asking why they can't be stopped is there any law violation and the question is genuine and the other one is not the same
Comment: Are you asking why the speed of photons is always $c$ in a vacuum? As the answers to the other question show photons can be stopped in a  medium. In that case it would be a duplicate of [Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?](https://physics.stackexchange.com/questions/2230/why-and-how-is-the-speed-of-light-in-vacuum-constant-i-e-independent-of-refer)
Comment: @johnrennie https://physics.stackexchange.com/q/394116/ This is also a duplicate why don't you bother about this
Answer: No, we cannot make photons travel at any value other than the speed of light. It is a postulate of the theory of relativity and it works because solutions to the equations of electromagnetism indicate that light/photons must travel at a constant speed regardless of observer. A way to think of it is like, because photons have zero rest mass that is why they can travel at the only other speed available that is less than the speed of light, that is: light speed.
One can presumably slow down light in optically denser media but in reality the light does travel at $c$ while bouncing and interacting with atoms in the medium so it only seems that light is slowed down by refraction.
Comment: Yes, indeed. In between interactions of absorption and re-emissions the photons always travel at $c$ but it's the extra time due to these interactions that makes it *seem* that light is slowed down.
Comment: So photons don't slow in a medium do they keep colliding which makes them apparently slow?

Can we have a photon at rest?


Send UDP packet to fpga spartan 3e via ethernet

Question: I want to send UDP packet to fpga which includes microblaze. But i have a problem about ip address. Where can i get the ip address of fpga.
Answer: You have to assign a static IP for the mac address and use that IP in your FPGA code for filtering n etc.,If your board is not on any network say one to one Ethernet to your computer then just VHDL coding would do.
Answer: Your FPGA itself does not have an IP address.
If you have an evaluation/prototyping board there often is a sticker with the MAC address assigned to this board.
Everything regarding IP address processing and UDP port numbers is up to you and has to be implemented either as logic on the FPGA itself or as software for the Microblaze.


How does b4 fix pawns in this rook endgame?

Question:
Here, it is said that after 1.Re7 Rb8 2.Kd3 a6, white plays b4 to fix the enemy pawns. But I don't understand: how does it fix pawns? How is b3 any different? What does it mean to fix enemy pawns?
Comment: You should make clear in the question that your question is about the position after 1.Re7 Rb8 2.Kd3 a6, as that a6 move changes the pawn structure a lot.
Comment: No one seems to have mentioned that "to fix" in English has at least two different meanings: to repair, or ,to lock in place (like a fixed gear bicycle). It's probably the second meaning here. (Can also mean things like "to prepare" as in "to fix a meal").
Answer: It definitely prevents Black from playing ...c5, at least temporarely. I wouldn't say Black pawns are "fixed" though. Anyway, isn't Re7 a much stronger move?
Comment: It's 3.b4, not 1.b4.
Comment: Isn't Re6 better? It seems to get either the b or g pawns for sure.
Comment: @MartinArgerami 1.Re6 Kf7! 2.Rd6 and now Black can choose between 2....Rb8 or soem crazy rook-ending counterplay with 2..Rf8
Comment: Of course. For some reason I was thinking Kg7 instead of f7.
Answer:
b4 is just weak here.

Instead 1. Re7 (get your rooks on the 7th rank!) almost wins on spot. One can then try 2. b4 according to what black plays.
Comment: The question has 1Re7.  b4 is only played on the third move.
Answer:
b4 fixes the black pawns a to c, because they cannot advance without support.

In the original position, 1. b4 would not fix the pawns. Black could play ...b6 followed by ...c5 at the right moment. After 2. ...a6, ...b6 is not possible anymore without support. And without ...b6, ...c5 is not possible. So the black pawns need support by their King or Rook to advance. They are fixed.
I know the term "fixed pawn" only in situations where the pawn cannot advance even with support. P.e. w a5, b4, c5, b a6, b7, c6 the pawns are fixed. It is obvious for the a and c pawns. If the b-pawn advances, it will be captured, and any recapture by a rook (a recapture by the king is obviously illegal) will result in serious material loss.
Answer: It does not fix the pawns directly.  As black pawns can still  move without being captured.  But it ensures that black cannot force a passed pawn even if they sacrificed one pawn to do it.


Target specific participant in Google Hangout API?

Question: I'm trying to build a Google Hangout App as a game, but I'm unsure with the current Google Hangout API how to target a specific user.   So for instance, if I want a specific participant to be the only person that can see a div in the app, how would I go about limiting based on a specific user ID?
Answer: You can get the Participant of the current user by using gapi.hangout.getParticipantById( gapi.hangout.getParticipantId() )
(See https://developers.google.com/+/hangouts/api/gapi.hangout#gapi.hangout.getParticipantById for more details).
The Google ID is stored in the Participant object in the person.id field (see https://developers.google.com/+/hangouts/api/gapi.hangout#gapi.hangout.Participant for details about the Participant object).
So once you have the Participant for the current user, you can check the person.id field to see if it matches the person in question. There are other fields that may be more suitable for your exact needs, however, so I encourage you to look over and experiment with different fields and methods.


Starting row of laminate flooring

Question: Just wondering how to start the 1st row of laminate flooring.
I have a door to deal with right off the bat. Wondering which is the better option (see diagram). This diagram is not to scale. The wall is 20 feet long with a standard door opening.
Comment: I should have mentioned that the room just past the door has carpet, which will NOT be removed. Probably an important piece of info I should have included in my original post.
Answer: Option B is a fine way to start, if possible check 2 things. If possible shift your row if you can to get a potential butt joint out of the doorway. It is always best to eliminate joints in the doorways since it is always a high traffic area.The elimination of the added piece in option 1 is the reason I did go for option 1.
Secondly, adjust how much you cut out of the start row to minimize the problem of having a really narrow strip to finish on the other side. A 1" strip can be glued onto the neighboring lap if need be, a 1/2" strip will be delicate but can handled with glue too. Just make sure you will finish well. you do need to leave a 1/2" room at all solid objects in the room to allow the floor to float within the room, it will move, it will expand and contract with seasonal, and changes in room humidity/conditioning.
Answer: In general, all tile and plank layout should be done to maximize the size of the pieces along both the starting wall and the finish wall. in general, unless you have at least 3/4 of a unit at the end wall, you wan to cut both the starting and ending rows to have a more balanced appearance. (Even with 3/4 of a full plank, you may still want to divide the difference for a more symmetrical appearance).
Assuming fairly square walls, you figure out the size of the edge strips as follows:

Compute how many full units fit across the room.
Compute the extra width beyond the full units.
Add that to the width of a full unit.
Divide by 2.  This is the width of your starting row and finishing row. (Your full rows
will be one less than the maximum total you first computed.)

Examples:
Room is 10'2" feet wide and tiles/planks are 1 foot wide:

 1. Maximum full units is 10
 2. Extra width is 2"
 3. Extra plus one unit is 1'2" (14")
 4. Half of that is 7". (Starting and ending rows are 7" each, 9 full units in between)

and
Room is 10'10" wide and tiles/planks are 1 foot wide:

 1. Maximum full units is 10
 2. Extra width is 10"
 3. Extra plus one unit is 1'10" (22")
 4. Half of that is 11". (Starting and ending rows are 11" each, 9 full units in between.)

In general, flooring will be finished with a molding over a gap left around the perimeter (usually 1/4" to 3/8" depending on the flooring material). This gap is needed to accommodate shifting of the flooring materials due to seasonal shrinking and swelling.
The door transition needs to be adjusted to reflect the door saddle or other capping mechanism. A gap is needed at that transition as well as the wall edges. You could use either A or B if the door transition cover will give at least a 1/2" cover of the edge.
Comment: that's a great example. The width of the room is 18'8". By using your example the starting and finishing plank should be 10" wide with 17 full units in between.
Comment: Don't forget to account for the expansion gap on each side. Subtract double this value between the third and fourth steps.
Answer: I would start up in the top-right corner of the diagram, that way you have to cannibalize say two tiles, to make up for the little bit of space you need to cover between the edge of the first column of tiles and the door jam, as opposed to cutting off say two inches off of every single piece of flooring in the entire first column.
Alternately I guess you could also start in another corner of the room, preferably with a strait wall that has no doors!
When I redid the flooring in my bathroom, I was lucky enough to have a slight gap between the trim and the plywood under, so I was actually able to slide the flooring a little bit closer to the actual wall, and minimize cutting!

Starting row of laminate flooring


How to use Content-Type: Multipart/Related

Question: I want to send a binary file to the user and have some HTML display on the browser.  I'm using a CGI-BIN script with apache2.  I found this example on page 4.  The link also shows details about the multipart/related content-type.  Here's what I tried so far:

Content-Type: Multipart/Related; boundary="boundary-content"; start=""; type=\"text/plain\""

--boundary-content
Content-Disposition: inline
Content Type:text/plain
Content-ID: <abc>

hi

--boundary-content
Content Type:application/octet-stream
Content-Disposition: attachment;filename=myfile
Content-ID: 2

...

--boundary-content

The whole thing after the first Content-Type line shows up as a single plaintext attachment.  How can I make the browser say hi and prompt to download myfile with contents of ...?
Answer: i do not think browsers understand multipart MIME responses


Disable password authentication on mounting a device

Question: I'm using Debian linux. When ever I try to mount a NTFS HDD, it asks password to root. How can I give root permission permanently?
Answer: You may want to look into pmount
pmount ("policy mount") is a wrapper around the standard mount program which permits normal users to mount removable devices without a matching /etc/fstab entry.
In this case it sounds like you would want to use the -p flag: If the device is encrypted (dm-crypt with LUKS metadata), read the passphrase from specified file instead of prompting at the terminal.
Instead of prompting you every time it mounts, it will instead consult the passphrase file and mount silently.
Comment: I do not think the question is about the encryption, but the password to mount the hard drive.
Answer: Old question but pops up in searches: the simplest GUI solution (tested in Debian-based and RH-based systems, I think it works allover Linux): Gnome Disks.


BackupPC incremental backup problem

Question: I have BackupPC  application in CentOS 5.. clients are windows  and RHEL machines.. I could take the Fullbackup for the client mahines ..But I can't take the increental backup.. When I  took the incremental backup , it start incremental backup, but after completion of the task .. i see that the backup directory contain full back of all the data ... what is the reason?   pls help me
Answer: Take a look at the documentation, it's meant to appear that way:

BackupPC "fills-in" incremental backups when browsing or restoring, based on the levels of each backup, giving every backup a "full" appearance. This makes browsing and restoring backups much easier: you can restore from any one backup independent of whether it was an incremental or full.

An unrelated note: Please try to write correct English on web forums. It's very hard for non-native speakers who have only learned "the Queen's English" to understand what you're saying otherwise.

BackupPC incremental backup problem


How to Retrieve WiFi Password when "Show" is grayed out?

Question: I set my own Wifi password and am admin for my computer. I need to add a user, but the password is not what I thought I set.   With several Wifi users I want to see my Wifi password so I don't have to set up everyone all over.  In the Network Properties box, the "Show characters" box is grayed out and there is no UAC shield shown.  Can I run that control panel as admin?  How?
Comment: Hello, and welcome to Super User. If you found your answer, please leave the question as originally asked and post your answer in the correct field below. This will help other users with the same problem.
Answer: Open command prompt with admin privileges and type this:
netsh wlan show profiles [NetworkName] key=clear

where [NetworkName] is your network SSID with no brackets, press enter, the last line of the list should show your network password.
Answer: Thanks, but I figured out my actual mistake(s) AND HAVE FOLLOWUP.
SOLUTION:

I use MAC address Account Control and I had forgotten that I needed to add the MAC to my secondary (bridged) router.  The new iPhone is now on the target router.  I was thinking that my primary (linksys) router was running this circus.
The password box in the Vista WLAN Status showed 8 dots leading me to conclude the password is/was not my longer 'normal' passphrase, when it actually still was.
The secondary router is an AirPort Extreme and entering the setup ap, via LAN, in Manual setup allows seeing that I had some MACs already added as well as the passphrase...

...FOLLOW UP...
HOWEVER  SomeNick, It'd be nice to be able know how to do as you suggest, but I get the error that 'key' is not a valid parameter for netsh.  Omitting the 'key=clear' yields a valid response, but the last line is only:
"Security key  : Present"    Obviously, not in the clear.
I dusted off my DOS experiance and poked around the command help /?, but no hint there.
Googling to uSoft and reading up on netsh, I was able to run netsh and poked around with varying success in general trying some variations at the netsh prompt, but 'key' is still not a valid parameter/argument... even though uSoft's technet (wlanShowProfiles) says it should work...!?!?!?
 ...
My command window does show that I am as Admin.
FWIW:Vista Home Premium.
Regards
Comment: I'm guessing that `key=clear` is not supported on Vista. It is on Windows 7 (confirmed using `netsh wlan show profiles /?`)
Comment: You should post the followup part as a comment to @SomeNickName.
Comment: When I tried a comment, a message said something about me not having enough status.  I don't find this interface very friendly,sorry.  Enter also terminates input, so the interface needs some getting used to. Regards, Steve


n-copies of integers as an algebraic subgroup of p-adic integers

Question: Let $\mathbb{Z}_p$ denote the additive group of $p$-adic integers. The group of integers $\mathbb{Z}$ can be viewed as a dense subgroup of $\mathbb{Z}_p$ generated by the element that projects to $1$ mod $p^n$ for all $n$. The same should be possible for the group $\mathbb{Z}^n$, but I don't see how to describe the homomorphism $\mathbb{Z}^n\hookrightarrow\mathbb{Z}_p$ on generators even for the case $n=2$. Any hints?
Comment: (1) Show that $\mathbf{Q}_p$ does not have finite dimension over $\mathbf{Q}$. (2) Deduce that there exists a $\mathbf{Q}$-free family $a_1,\dots,a_n$ in $\mathbf{Q}_p$ (3) Deduce that there exists a $\mathbf{Q}$-free family $b_1,\dots,b_n$ in $\mathbf{Z}_p$. (4) Conclude. [Alternative to (3) is to find explicit families: either use algebraic numbers as in Neil's answer, or use a transcendental element.]
Answer: Choose a prime $q$ congruent to $1$ mod $p$, so $q^{1/n}$ exists in $\mathbb{Z}_p$.  Then define $\phi\colon\mathbb{Z}^n\to\mathbb{Z}_p$ by $\phi(a)=\sum_{i=0}^{n-1}a_iq^{i/n}$.


Does .NET create a string intern pool for each assembly?

Question: I have a situation where I will encounter lots of duplicate strings which will persist in memory for a long time. I want to use String.Intern but I don't want to invade any potential application resources since my project is a library. How does this work?
Comment: Meh, interned strings are reference-counted.  The primary object that holds a reference is a table (similar to HashSet) that's owned by an AppDomain.  Unloading the appdomain empties the table, decrementing the reference count.  The vast majority, if not all, strings should disappear.  There is no "invasion" danger.
Comment: A bit off topic but while searching various informations about string interning I've found this very interessant blog article : https://blog.benoitblanchon.fr/modify-intern-pool/ . See also associated source code.
Answer: The intern table for strings is CLR-scoped:

First, the memory allocated for interned String objects is not likely
  be released until the common language runtime (CLR) terminates. The
  reason is that the CLR's reference to the interned String object can
  persist after your application, or even your application domain,
  terminates.

So not only the intern table is not assembly-specific, but it can outlive your assembly. The good news is that duplicated strings won't be a problem since same literal strings exist with the same reference once interned. So Interning is recommended:

The common language runtime conserves string storage by maintaining a
  table, called the intern pool, that contains a single reference to
  each unique literal string declared or created programmatically in
  your program. Consequently, an instance of a literal string with a
  particular value only exists once in the system.

string s1 = "MyTest";
string s2 = new StringBuilder().Append("My").Append("Test").ToString();
string s3 = String.Intern(s2);
Console.WriteLine((Object)s2==(Object)s1); // Different references.
Console.WriteLine((Object)s3==(Object)s1); // The same reference.

Comment: okay.. but in this case, these two strings should be a single reference: typeof(int).Name and "Int32" declared as variable. why they are not?


How can I remove MvcMailer, T4Scaffolding, and other dependancies and restore my program?

Question: I tried to install MvcMailer and as soon as I added the package my project it died.  I started getting all kinds of error messages concerning dependency conflicts with different versions of  T4Scaffolding..versions 1.0.7 and 1.0.8.  So I uninstalled the MvcMailer.
When I run the program I still get the same message:  A different version of T4Scaffolding is already running in this instance of Visual Studio
Please restart Visual Studio to avoid unexpected behavior.
You won't be able to use scaffolding until you restart Visual Studio.
And my models have error message like:
The type or namespace name 'ColumnAttribute' could not be found (are you missing a using directive or an assembly reference?)
Or
The type or namespace name DatabaseGenerated could not be found (are you missing a using directive or an assembly reference?)
I am using EntityFramework 4.50501 SP1Re    l.
MvcMailer seems like a great idea but since I installed it I can't run my program anymore.  Is there anyway that I can simply get back to having my program revert back to the settings before I installed MvcMailer?
Answer: In the root of your project there'll be a Packages folder.  Deleting T4Scaffolding version 1.0.7 should resolve the conflict.