So many answers in comments

Question: I can see previous meta discussions on what should be a comment and what should be an answer, but what I'm wondering is, why are so many users posting answers, sometimes quite in-depth (if compact) answers, as comments? Does anyone have any insight? Should there be more encouragement (not any sort of coercion) to actually put things in answers even if they are succinct yet complete?
Comment: If you incorporate information from a comment into a proper answer, feel free to flag the comment as "no longer needed". A comment should never prevent you from adding an answer that can be properly scored and critiqued by the community.
Comment: [Related on meta.SO](https://meta.stackoverflow.com/a/253048/6296561)
Comment: @ColleenV I'll certainly remember that when I dive into the long-unanswered questions :)
Answer: Huh, weird. This gets asked often enough in metas, and I was fairly certain it was asked here too, but for the life of me I can't seem to find it. Anyway, here's the wisdom of the ancients on it.
Bottom line is, people develop a certain 'answer barrier', meaning, what they don't consider a high quality answer for whatever reason1 goes in a comment instead because the alternatives would be to either not guide the OP in any way or to post an answer they themselves aren't too satisfied with.
I disagree with some folks thinking this is a way to avoid the possible penalties of a low-quality answer (you can't downvote comments) as these folks are often well-intentioned but indeed, this is not how comments are supposed to work. There's occasionally some friction when folks come to meta to complain about a comment-answer being removed by moderators.
Regarding your last question, I don't recall any recourse sites have come up with other than some guidance in meta posts asking people not to do it or a more strict/systematic removal of comment-answers by site moderators so as to make intolerance against them part of "site culture". Both options are far from ideal, obviously: Meta posts create a temporary hype but they tend to get forgotten over time and there's the friction thing that comes stricter moderation (accusations of censorship and hostility etc. being the most glaring, although not the best examples) and if you did come up with an idea, it might well be worth a discussion or feature-request!
By the way, I ironically (?) started typing this in a comment and then just realized the topic of the post I am comment-answering on . . .

1: The most common reasons are that either the question is close-able and answering off-topic posts is explicitly discouraged, or they don't have the time to verify their claims, or think they don't have the expertise to deal with all the nuances of the question, or they feel the answer is incomplete for any other reason.
Comment: @choster does it seem fair that this one person gets special treatment when all they have to do is type in a different box? It's their choice, but personally I think it's ridiculous that a well-respected community member cares so little for the site that they would subvert one of the mechanisms that help people find credible answers to their questions. I'm opposed to community wiki comment conversions. Write a proper answer and take credit for it. We can use the information in the comments without copying word for word.
Comment: If I may offer a contrasting anecdote: on Physics we somewhat aggressively delete answers in comments, sometimes with another comment left to explain what happened, and we have done this even for well-known topical experts in a few cases. Of course people complained but overall it doesn't seem to have had any lasting negative effect. Meanwhile I _think_ I have noticed that people are less prone to answering in the comments than they used to be, so perhaps aggressive deletion is a component of an effective approach in the long term.
Comment: I'll add that sometimes there is friction when comment-answers are **not** removed by moderators. I've seen it run both ways. Also, I don't know if [this](https://ell.meta.stackexchange.com/questions/3534/lesser-of-evils-on-ell-comment-vs-lq-answer?rq=1) is the meta question you were looking for, but it's definitely related.
Comment: At EL&U, where at least one very well-respected user answers almost exclusively in comments on principle, the mods have taken to copying the content of the comment into an answer, attributing the commenter, but then making it community wiki so that they do not collect reputation for it.
Comment: @choster does that in any way encourage people to write more answers instead of comments though? It's surely an effective way to deal with legitimate unanswered questions but it's not 'coercing' people into writing more answers.
Comment: @ColleenV - I will do a comment-to-wiki-answer conversion on occasion, but only when (a) the comment/answer seems like it would be extraordinarily helpful to the user community at large, and (b) no one else has answered the question. I'd much prefer to see a well-written answer present so I can simply delete the comment outright – I think that's better for the site in the long run.
Comment: @J.R. I know that's the conventional wisdom when it comes to comment-answers, but I think the first up-vote of that wiki takes the question off the unanswered list even though it hasn't really been properly answered. Better (IMO) to leave the comment until someone answers the question if it's really that helpful. On the other hand people read the comment and think the question is "answered" and move on so it never gets an answer so sometimes I ditch old comments on questions with no answers. There's no perfect solution.
Comment: @DavidZ: I am not often on Physics.SE, but I like that approach. It's the same one the mods use on RPG.SE, and it's effective at making sure answers go in the answer area rather than the comment area. We even have an FAQ meta about it there: [Should users refrain from answers (or partial answers) in comments?](https://rpg.meta.stackexchange.com/questions/6533/should-users-refrain-from-answers-or-partial-answers-in-comments)
Comment: This is a fairly apt SE to get into discussion of what counts as irony, but I shan't
Comment: @ColleenV It's an exceptional case for a known authority on the subject matter. I'm not defending the practice explicitly, I'm just pointing out an attempt to find middle ground between allowing comment-answers (in contravention of policy) and deleting them outright (with a loss of useful information).
Comment: @DavidZ If the [Physics.se] mods want to take the time and deal with [the fallout](https://ell.meta.stackexchange.com/q/3302/) that's fine. We're pretty aggressive (20K+ comments deleted as a team), but policing comments takes time that I would rather spend doing pretty much anything else.Comment-answers can be handled by the community. When you see a comment that has been covered in an answer, flag it as "no longer needed". If no-one has up-voted it, 3 users can delete it. (SO DON'T UP VOTE COMMENT-ANSWERS!) 1 more flag per 3 votes above 3 (i.e. number of flags = 3 + score/3).
Comment: @Colleen Sure; I didn't mean to suggest you should necessarily do the same thing we do, I just wanted to offer an alternate perspective to some other comments.
Comment: @DavidZ I didn't really mean to let my frustration bleed through like that :) I would like for people to not see this as a mod issue. We've had tons of moderator flags for comment-answers so I'd rather empower the community to help deal with it.
Comment: @Colleen No problem at all :-)
Comment: So then, comment-answer is not a verb and a noun, right?|| I sometimes use the pity factor. A question should be closed but the OP seems really desperate and the question does not merit a full answer or falls just outside the guidelines.  Just saying....
Answer: I probably get "questioned / criticized" more than most ELL users for making comments that others think should have be posted as formal "Answers".
I don't really see any harm in my approach, and I certainly don't care if there happen to be "site guidelines" advising people not to do this. Within reason, each site is free to honour such guidelines to the extent that the specific user base (and their elected representatives, the mods) see fit.

Just today I posted this comment - which received two upticks, and two comments suggesting I should have posted what I had to say as an answer rather than a comment.
Part of my reason for just commenting was that it takes much longer for me to write an actual answer. And that's not just because (as implied by my "nom de plume" here) I'm very slow at typing - it's also because I'm acutely aware that my first impressions are often mistaken. In the case of the linked comment, that's unquestionably the case from my perspective (the eventual answer was much more accurate than I was).
A related factor here is that if someone like me posts an off-the-cuff reply / reaction to a question, there's every possibility that someone else will be minded to take issue with the substance of whatever I say (as opposed to simply taking issue with me saying it in a comment rather than an answer, which I do sometimes find rather tiresome).
Personally, I suspect that people often start arguing / nitpicking over the finer points of detail raised by a question because they don't agree 100% with some simplistic response given in a comment. To my mind, this can eventually lead to higher quality answers, because two (or several) heads are better than one.

TL;DR: I already feel under enough pressure to answer more and comment less. I'm not asking to be treated less severely than I am at the moment (but I do get irritated sometimes if I think my "relevant" comments have been over-hastily deleted), but please don't ask the mods to be even harsher than they are. So far as I'm concerned, they do a great job, and the balance is currently just about right.
Comment: I don't really like it when we scold each other in the comments - I think it detracts from how friendly ELL actually is and we should do so sparingly. How do you feel about someone taking the information in your comment and using it in their own answer instead of admonishing you to write one? (I don't mean copy and pasting your words into a wiki - just starting from the information you've provided)
Comment: I've said several times both here and on ELU that I don't mind if someone copies my comment text verbatim into an answer, but that's not ideal, obviously. If I thought it was good enough for an answer I'd have posted it myself (*unless* I was only commenting because I'd actually *closevoted*, in which case I sometimes think it's only fair to give the requested information anyway, if that's not too difficult). But if someone uses my comment as a ***springboard*** for a more "complete" answer, I see that as flattering for me *and* beneficial to both that user and the site itself.
Comment: I still don't think that it's a good idea to forcibly convert comments into answers as part of a system (mod-driven or otherwise) even though you might be OK with it. I would rather see a "nudge" type system that notifies you if a question you've interacted with has passed a certain threshold of "unansweredness" so that you could decide what, if anything, you want to do about it. It's usually better with volunteers to just let them volunteer to help.
Comment: ...I would also just add that if I've posted a comment that is or comes close to being an acceptable answer, AND no upvoteable answers have been posted within 48 hours of a question being raised (a "valid" question, that hasn't been closed), I think it would be excellent if the system could automatically (or thru deliberate mod intervention) convert my comment into an answer AND force my account to post a bounty on the question!
Comment: Some folks are hesitant to use information from comments as a start for their own answer because they don't want to "steal" it - I was hoping to get you on record that you don't mind if people start from your comment. I'm not so sure about automatic conversion into an answer... If someone wanted a comment to be an answer, presumably they would have made it one. I don't think it's fair to essentially force someone to post an answer. I'd rather just delete it after the asker has probably seen it and let a new user looking for questions to answer tackle it.
Comment: I was being very specific in saying that the idea of "auto-converting comment into answer" should only apply *if no upvoteable answer has been posted, after at least 2 days*. In case it wasn't obvious, I should also have explicitly added that I probably wouldn't be so happy if this was done to one of my comments *if I had closevoted at the same time as posting it.* Another relevant point here is I'd like to think that at least *sometimes*, a user who rarely if ever posts answers might be more inclined to do so if they could take at least part of their material from a "trusted source" (Me! ;)
Comment: Yes, a "nudge" approach sounds like an excellent idea! Personally, I'd be very happy to have the system automatically "shame" me into either taking the time to post a fully-fleshed-out answer myself, OR post a bounty that might encourage someone else to do so (on "neglected" questions that I didn't VTC). I'm not sure if this would be a viable "meta meta" SE question / feature request, or if it's more specifically relevant to ELL (and perhaps ELU). Either way, I'd love to see *you* raise it wherever you think it fits best within the system!

So many answers in comments


What are the advantages of using the Java debugger over println?

Question: I always use System.out.println(...) to debug my code, and it works pretty well. In which cases do you use the eclipse java debugger? I never had to use it and the little bug symbol is still ab bit mysterious to me. Are there cases where the debugger helps me that I can´t solve with a println?
Comment: "What do you mean, you can't solve that with `println`?  `println` harder!"  But seriously, my point is that just because you *can* solve something with `println` doesn't mean that it's the easiest, best or fastest way.  So what kind of answer are you looking for?  Also, don't forget that using print statements means you're constantly modifying code, which 1) takes effort and 2) introduces a possibility of accidental screw-ups.  Why not use a logger?  And is there a chance that your unit tests aren't as good as they could/should be?
Comment: http://programmers.stackexchange.com/questions/78152/real-programmers-use-debuggers?rq=1 and http://programmers.stackexchange.com/questions/131377/whats-the-benefit-of-avoiding-the-use-of-a-debugger?rq=1 already have quite a few opinions on this topic.
Comment: You should always be using the debugger!
Comment: @Bernard, your comment is actively useless. Why should he? It's exactly what he's asking.
Answer: The problem with println debugging is that the printlns themselves are a problem.
When you're debugging using println, you have to modify your code to do it.  This means you need to already know, or at least have a pretty good idea, where the bug is before you start debugging.  And if you already know that, you probably don't need to debug anyway, as (IME at least) the mian reason for debugging is to find where a bug is, not figure out how to fix it.  Once you have the bug pinned down, the solution is usually obvious just from the context.  (Not always, of course, but usually.)
If your println diagnostics turn out not to give you useful information, or not to give you useful enough information, you need to close the program, change the code, recompile, and then get back to the point you were at to reproduce the bug.
Once you're done with finding and fixing the bug, you then have to change your code again to remove the println statements.  (Let's hope you don't miss any and then ship the product with debug output left in!)
An interactive debugger doesn't have these problems.  You don't need to know what you're looking for ahead of time; you can examine the values of any arbitrary variable at any time it's in scope.  You don't need to modify your code, because the debugger is external to your program.  And therefore you don't need to stop debugging, change your code and recompile to look at something new.
That principle alone--inspecting the code from the outside instead of having to instrument it (and then un-instrument it) manually--is the reason interactive debuggers have become the favorite method of debugging among modern programmers.
Answer: Every case...
Granted, I'm not 100% sure about Java IDEs (and would welcome any corrections that aren't consistent with Java IDEs) because I use Visual Studio over C#/F# but adding variables to the watch list and using conditional breaks completely practically replaces println...

you don't need to rebuild to get additional information (you don't even need to restart your process/debug session)
you can remote debug a process on another machine
you can move the current execution while executing (drag the arrow that indicates the current line)
step into code/out of/over code based on whether or not you think it matters

And hell, I'm not even that great with the debugger, but it's still light years ahead of console debugging or digging through logs.
Comment: The most awesome thing I ever learned with the debugger was that you can rewind the stack by dragging and dropping the yellow "next statement" arrow.
Comment: Also: You don't have to spend a frantic evening before a deployment removing all of your `println` statements.
Comment: @Mike Brown: dragging the line indicator is one feature eclipse does not have, but it does have a button to rewind the stack.
Comment: You can also update variables (I don't see this in your list) and (at least in VS) execute methods using the immediate window.  This can be quite useful in some situations.
Comment: Another cool feature is the immediate window, it lets you execute statements and see the output with the current stack.
Answer: There isn't really any information a debugger can give you that you could not gain through print statement as well, but...
it's just so much faster and more flexible. Words can't describe the power you get when you can freely look at what the code is doing while it's running.
All in all, I'd estimate that using a debugger typically speeds up the debugging process 10 times. Probably 100 times in cases where there's a lengthy build or deployment between the time where one print statement gives you information about where to next, i.e. where to add another print statement, and the time you can see the output of that new print statement. In a debugger, all it takes is a single click, maybe half a second. If you have to do a full rebuild and deploy to an app server, it could take half an hour.
Answer: in my experience, the eclipse debugger (or any step-by-step debugger, for that matter) helps a lot more than println statements, because:

they don't require several recompiles for what might be a small problem (this might seem like a small problem for small projects, but can quickly escalate for large to very large ones)
they often allow debugger-time altering of the variables, which might be handy as well.

(these are just the most basic advantages I found)
However, the debugger is not always that nice:

debugging multithreaded programs with a step-by-step debugger is pure hell. In the first writing step, I usually use a logging system with a byte-by-byte debug flag (think global debug, module 1 heavy debug, module 2 heavy debug, ...). It's saved me a lot so far
debugging real-time programs where the real-time character is vital to the algorithm (the thing I have in mind was my personal version of face detection, which required the face to move smoothly. It didn't when only getting a frame every couple of seconds because of debugging - granted that this could be solved by taking a video input, just giving an example)

in short: for small, handable projects a debugger is your largest friend. For large projects (which you often work on with a lot of people), an extensive write-time logging is your even larger friend. Or at least mine.
Answer: You should have googled it first. Debugger in Eclipse already contains a lot of functions that you don't need to define. Other than that, System.out.println() statements might do for you in a simple small project but in a project where many members are working or you have large number of files, you just can't keep adding these statements. It is good to have breakpoints.
I suggest you to take a look at this
Answer: I hardly ever find that I need the debugger - but when I need it, I really need it.
One nasty case is where you use println to print out an object, and it prints out "null". After staring at the code for ages, you are convinced that the object cannot be null at that point. And yet, that is what println says. This can waste hours.
In the debugger, you will find immediately that the object is not null. However, the toString() method has been over-ridden to print out the value of some field in that object. The value of this field is, of course, null.
The debugger lets you explore a wider range of questions, more quickly, than using println. But in many simple situations, println is good enough. Just don't waste too much time in those cases when it isn't good enough.


What about downvoting comments?

Question: Comments are widely used (and misused IMO) for different reasons. At times they are real answers or elaborations of answers, at others they are used just to express personal impressions on questions or  answers.   Most useful and interesting comments usually receive a good numbers of up-votes and become part of the answers they relate to. But what about unconstructive or unuseful comments? Why don't we have the possibility of downvoting them instead of having to argue about their unhelpful content. In short, if comments ( like questions and answers) have the dignity of being upvoted or flagged,  why not that of being downvoted too.
Comment: This is probably better asked on Meta.StackExchange, but I imagine the answer is to promote a positive atmosphere and ameliorate bickering and possibly to encourage contributions from people who otherwise refrain from posting answers for fear of being downvoted (or to mitigate fear generally). The reason comments have the "dignity" (so called!) of being flagged is specifically so that non-constructive or inflammatory comments can be removed. In general, I've enjoyed that comments can't be downvoted.
Comment: Yeah, there are a [couple](http://meta.stackexchange.com/questions/3615/should-downvoting-be-allowed-on-comments) of [related](http://meta.stackoverflow.com/questions/253178/why-cant-i-downvote-comments) questions on Meta.SE.
Comment: @Mari-LouA - your comments are rarely unuseful -- so you think there is no point in making comments downvotable!!!
Comment: I don't think they would make a great deal of difference in the end. If they are unconstructive and/or obsolete I will flag them, and the mods usually have deleted them. Especially after the election, I have since found my flags are taken more in consideration. Before the election, many of my flags on comments were "declined" or "disputed". Maybe I have become more discerning, or experienced with age—who knows? It's rare that I see comments which are offensive, but users should immediately flag them as such. Offensive comments are removed pretty fast.
Answer: It's not possible to do this because Stack Exchange administration has decided it's not needed. See this Meta SE post: Allow downvoting comments. So discussion here is unlikely to make a difference.
That said, I agree with Josh61 that it would be beneficial to be able to downvote comments. Flagging only seems appropriate to me for comments that are obviously rude or non-constructive. I don't think flagging is right for comments that present information that at first appears to be correct, but then turns out to be wrong: these require too much subjective evaluation to be flagged for deletion. (Just like incorrect but valid answers.) It also doesn't seem right to delete all comments that present controversial but valid opinions. (And I don't think the mods would do this).
Yes, people can respond to comments like these with new comments, but in order for this to be helpful it has to either convince the original poster to delete the unhelpful comment (which is rare) or gain enough attention and upvotes to appear alongside the unhelpful comment in the collapsed view of comments. The second scenario can be difficult when addressing comments on old or rarely viewed questions.
Answer: The following answer only applies to the main site. Meta is expected to have discussion, so comments tend to be treated differently here.
Comments are not like answers or questions. They are not meant to last. If you see a comment that is unhelpful then please flag it so that it may be deleted.
Upvoting of comments is there, ideally, to raise the signal to noise ratio of comments. Comments with up votes will be seen above those without if there are 5 or more comments. Once a comment has been actioned it should be deleted. If you see a comment that has been actioned, then please flag it as obsolete.
If people stopped treating comments as a place to have a chat, then there would be less of a problem. (I mean, we have chat rooms for chat.)
Comments should only be made to comment on how to improve a post. If you feel you are getting into an argument then take it to chat. If you feel like you need to make a joke, take it to chat. Don't be surprised if a comment of yours gets deleted.
Comments don't get downvotes because they shouldn't stick around long enough to need them.
Comment: I suppose it's inevitable that *on average* mods will think users post far too many irrelevant chatty comments, because you guys get the donkey work of tidying up afterwards. But I assume the fact that we don't get castigated on a daily basis means the current level of "off topic" comments isn't *intolerable*. As to OP's specific request, if I disagree with a comment (one which doesn't justify flagging for mod attention), I think it's quite enough to post a "counter-comment" and see if that attracts more upvotes than the original. Actual *downvoting* of comments is completely unnecessary.
Comment: Flagging comments is useless. I've flagged 95 questions/answers and only 6 of them have been declined; meanwhile, I've flagged 19 comments and 10 of them have been declined. Moderators just don't like to delete inflammatory, disrespectful, or snide comments for some reason.
Comment: [tag:feature-request] Please can I have downvotes for Dan Bron comments? :Þ
Comment: @phenry Possibly, or possibly they have a different opinion of what constitutes "inflammatory, disrespectful, or snide". I think outright censorship of someone's voice should be reserved for the most egregious cases, but then that's my personal political leaning.
Comment: I agree (kinda) with @phenry. Offensive behavior is *not* dealt with assertively here. One user responded to my comments (disagreement) with comments about *his foreskin*, or *masturbation* (the threads involved icebergs and 'big words' respectively.) My flags were ignored for days. A mod did join a chat room where I was trying to get said user to stop and finally addressed this, though. Look at the recent edit kerfuffle in meta. I think some mods are too reluctant to risk offending the offender. That's my only complaint though. Flagging isn't useless, but the mods aren't tough enough (imo).
Comment: @DanBron: also people are not going to stop using chat for screwing around talking about things having absolutely nothing to do with the subject, the site, or anything at all. Except when they do. Anarchy lives!!
Comment: @phenry I'm sorry to hear that you disagree with our decisions on your comment flags. I can tell you that we delete about 20 comments per day between us (us being the mods), so I don't really agree that comment flags are useless. I do think that we could delete more considering the name calling part of the "Be Nice" policy. That's something to work on.
Comment: People are not going to stop using comments as a place to have a chat. Case in point :)
Comment: For me, the most awkward aspect of the "Be Nice" policy isn't exactly "name-calling" in the sense of *"You are an idiot!"*. It's the boundary between *"What you just **cited** was rubbish"* (normally acceptable to me, since it only undermines the *reference*), and *"What you just **wrote** (your own words) was rubbish"* (not acceptable, since it undermines the *addressee*).
Comment: @medica did this happen *before* the recent mod election? Although I have had three flags ignored for weeks b/c I had notified an irregularity in one user's question. Eventually someone looked into it. I have no idea if any action was taken. Let me add however that the user I flagged hasn't repeated the irregularity (AFAIK).
Comment: @Mari-LouA - yes, it was prior to the recent election. But I've had other occasional comments (even worse than those) that I've flagged that were not acted upon until I rounded up a mod (for one comment about a week or more later) and asked why those comments had not been deleted. I do want to say that when I address a mod directly, they have been very good about removing offensive comments. Obviously, I try not to do that except for really bad/worrisome situations. I also have taken up the topic of sexual harassment briefly with SE mods, who acknowledge its existence.
Comment: @medica well it's good that when you directly contact a mod action is taken, but not so good that you *need* to do this. The few offensive/vulgar *comments* (*excluding* posts)  I have flagged have been dealt with pretty swiftly in my experience, but the comments were not aimed at me personally. Should that make a difference? I don't see why it should.
Comment: @Mari-LouA - No, it shouldn't make a difference, and I think flags are being handled more quickly. I guess what it might boil down to post-election is what do the mods think is flag-worthy.

What about downvoting comments?


How does a cell phone charger work?

Question: I have studied that there is a transformer which steps down the ac voltage after then bridge rectifier to convert into ac to dc and then given to filter, this is what I have learnt in books, but when I open a mobile charger I couldn't figure it out how it actually works?
Comment: Modern chargers use switching regulators. You might find some good information looking up the term "buck converter". The simple type you describe is outdated, and requires a very large, heavy, and expensive transformer, among other problems.
Comment: Here is a sample design from TI http://www.ti.com/lit/an/slua653c/slua653c.pdf lots are based on a flyback DC-DC topology
Comment: You should look at [this](https://electronics.stackexchange.com/questions/214101/how-does-this-wall-wart-switcher-work).
Answer: Phone chargers are incorrectly named. Most are 5 V power supplies. The charge control is done inside the phone. The power supply will continue to give out 5 V when the phone is completely charged.

Figure 1. Switched-mode power-supply block diagram.
How it works:

The mains voltage is rectified to provide a high voltage DC supply.
A transistor "chopper" switches this on and off at high frequency.
A small transformer steps this down to a low-voltage high-frequency AC.
A rectifier converts this to low-voltage DC.
The chopper controller feeds back to the chopper and adjusts the chopping cycle to maintain the required voltage on the output - usually 5 V.

Figure 2. Anatomy of an SMPS 'charger'. Image source: Analogic Tips.

Plug pins.
Four diodes for the bridge rectifier.
Smoothing capacitor for high-voltage DC.
Switching transistor.
Switching transformer.
5 V supply indication LED.
Output rectifier and filter.
Opto-isolator for feedback from the output to the chopper controller.
Comment: @pankajprasad - The complexity is so that the transformer operates at a high frequency, usually in the hundreds of kHz. The size of a transformer is almost inversely proportional to the frequency of operation. The circuitry to create the high-frequency requires DC to operate. This high frequency allows the transformer to be smaller, lighter and much lower in cost. The cost difference more than pays for the extra complexity. Other components such as the output filter can also be much smaller and cheaper.
Comment: Also the output can be made to be very stable over a wide range of input voltages - typically 100 - 240 V AC and 50 / 60 Hz. A regular transformer output voltage will not stay stable. Also the SMPS will be much lighter than a regular transformer power supply.
Comment: I have a small doubt, as the input is a voltage after chopper inverter also ac voltage come, then why to rectify and filter in the first stage we can directly step down the voltage and place a voltage regulator to control the output why we need this complex circuit...

How does a cell phone charger work?


How would an EMP affect a maglev train system?

Question: I'm looking for a description of how an EMP might affect a magnetic levitation train system that is NOT connected to the local power grid. Specifically, if the maglev was active, would the train be thrown off the tracks and rendered unusable, or otherwise disabled, or would it simply suffer a loss of power and then be able to reboot and run perfectly fine again?
Comment: A basic engineering principle for passenger carrying machines is to fail safe. They must be designed, built and proven to protect the lives of the passengers when bad stuff happens. For example, if an elevator loses power if will just stop, not crash and kill the riders. For an example similar to the question, consider the [*Shinkansen*](https://en.wikipedia.org/wiki/Shinkansen); it carries over 150 million passengers per year at an operating speed of up to 320 km/h. How many devastating earthquakes have hit Japan since 1964? And yet *nobody has ever died* because of derailments or collisions.
Comment: The physics are one question, but all passenger vehicles have many, many safety systems built in to prevent the hard realities of those physics. Underpower, overpower, and power-off are expected conditions that the system must deal with on a daily basis. It boils down to the needs of your story: If you need a safe stop, then there are secondary safety-wheels and skids and ablative brakes and such. If you need a catastrophe, then the track (or vehicle) control systems are fried and some (technobabble) safety systems failed.
Answer: To my understanding, a maglev train is propelled by magnets above and below the rails, that pulse in precise timing to send it forwards (or to slow it down when it needs to stop). These are also responsible for the levitation effect: the magnets hold the train a small distance above/away from the rails.
If your EMP pulse managed to kill the power to the magnets, the probable result would be the train dropping a few inches or so onto the rails and grinding along until it lost its momentum. Going at several hundred miles per hour, this would be dangerous in the extreme, but with such a tiny drop I don't think it would run off the rails unless there was a sharp turn (unlikely, given that you need to consider the G-forces on passengers when the train is operating normally) or the rails were unable to take the train's weight (which undoubtedly would be a building code violation).
This would terrify any passengers, beyond all doubt, and the resulting damage to the magnets would most likely render rails and train all unusable without expensive repairs, but I doubt you would have any casualties. Unless, of course, the timing is unfortunate enough to catch a train as it's about to slow down to enter a station, with another train on the same track at the other end of the station loading up with passengers.....
Comment: The rails already take the train's weight (the train pushes back on the magnets with equal force and everything), but the forces generated by it scraping against the track and slowing down are a different beast. Maybe some sort of emergency wheels or something that is normally within the clearance but gently slows the train by touching the ground first?
Comment: Worthwhile noting that maglevs need landing wheels for when they're operating at low speeds or need to stop. Not sure if they're also used as a safety feature.
Comment: My guess, @JoeBloggs is that they probably are. This assumes, of course, that the maglev is *not* the permanent-magnet type (you can't EMP a permanent magnet).
Answer: I think one might design a maglev train with induction braking that would be robust enough to use the kinetic energy of the train and permanent magnets to not only stop, but also maintain the maglev effect while the train was moving.  The train would still ultimately drop onto the rails, but not until it spent its kinetic energy braking / floating.
Induction brakes are already used on some maglev trains.
http://www.explainthatstuff.com/eddy-current-brakes.html

The simplest linear, eddy-current brakes have two components, one of
  which is stationary while the other moves past it in a straight line.
  In a rollercoaster ride, you might have a series of powerful,
  permanent magnets permanently mounted at the end of the track, which
  produce eddy currents in pieces of metal mounted on the side of the
  cars as they whistle past. The cars move freely along the track until
  they reach the very end of the ride, where the magnets meet the metal
  and the brakes kick in.
This kind of approach is no use for a conventional train, because the
  brakes might need to be applied at any point on the track. That means
  the magnets have to be built into the structure that carries the
  train's wheels (known as the bogies) and they have to be the kind of
  magnets you can switch on and off (electromagnets, in other words).
  Typically, the electromagnets move a little less than 1cm (less than
  0.5 in) from the rail and, when activated, slow the train by creating eddy currents (and generating heat) inside the rail itself. It's a
  basic law of electromagnetism that you can only generate a current
  when you actually move a conductor through a magnetic field (not when
  the conductor is stationary); it follows that you can use an eddy
  current brake to stop a train, but not to hold it stationary once it's
  stopped (on something like an incline). For that reason, vehicles with
  eddy current brakes need conventional brakes as well.

I could not find specific diagrams of how the induction brakes on maglev trains work.  If I were designing them I would have permanent magnets on a deadman switch swing out when the power went and then produce eddy currents to slow the train.
Frictional losses by the train falling onto the rails and "grinding along" (to quote @Pallaran) would make the emergency induction brakes kind of pointless. There has to be something to prevent this grinding.  The cheapest way would be friction pads like brake pads on the grind points.  But if you are using permanent magnets for emergency induction brakes you can use the same principle and use permanent magnets for emergency induction levitation, or electrodynamic suspension.
If there are permanent magnets on a deadman switch ready to tap the trains own kinetic energy and turn it into levitation and braking, the EMP-fried train would coast and brake until its kinetic energy was gone.
It was frustrating not being able to find a schematic of how real maglev trains  accomplish these ends.  Probably it is proprietary.
I envision a scenario where the heroes deactivate the brakes and trigger the Atlas rocket being carried on this train, the rocket exhaust now providing impetus and the emergency induction levitation turning back on when the train got up to speed.
Answer: EMP's generally will disable or outright destroy any complex electronics inside their effected radius.  Maglev trains are levitated using electromagnets, so the moment the EMP hit the track, the train would fall onto the track.  If the train were stationary, this wouldn't be too bad, but if it were traveling at full speed, with some reaching speeds of up to 375 mph, this would be disastrous.  The train would act just as if it were a traditional train running off of its rails, only at a much higher speed.
There are some protections in place, and electromagnetic suspension (EMS) systems are designed to run temporarily in the case of a power failure, but these systems generally only run for a short period.  Additionally, the systems to monitor and activate these emergency measures would more than likely be fried in the EMP itself.
As for EMP shielding, perhaps one could shield the controls themselves, but I am unsure if you could shield the electromagnets themselves, simply due to their location and function.
In the end it comes down to how paranoid the owners of this maglev system are.  If they believe that an EMP threat is viable, then perhaps they will shield the emergency systems, thus allowing the train to have a chance to save itself in such a scenario.  If they aren't as worried, then it will in all likelihood end in a catastrophic failure.
Note:  This answer is based on my own understanding of EMP's mixed with a small amount of research I did into maglev trains while writing this, so if something I said sounds suspect to you, I encourage you to research it for yourself.
Answer: Maglev trains are designed with multiple levels of redundancy so that catastrophic failure is exceedingly unlikely (or rather that it is an acceptable risk), if however your EMP managed to shut off all its power and fry all its redundant systems, the train (because of conservation of momentum) would indeed fly off the tracks at high speed likely killing everybody aboard and destroying itself in the process.
Comment: @Brythan I, too, disagree that the train would fly off the tracks. More practically, look at any picture of a maglev train and notice how the train is wrapped around the rails. The train wouldn't even fly off the rails on a curve, as the structure of the train would remain attached to the track, although the ensuing drop onto the track would surely be more damaging on a curve than on a straightaway.
Comment: Catastrophic failure and loss of life due to a power loss seem to indicate a very poor system design. Power loss is an expected problem. Such an operator would either fail to receive permission from regulators, be bankrupted by liability after the first power interruption, of fail to be funded in the first place.
Comment: Why fly off?  I would only expect that to happen on a curve.  On a straight, I would expect it to drop onto the tracks.  It might then fall off, but it would lose some momentum to friction.  And given the shape of a maglev, it might hold onto the track well enough on a straight enough section to stop on the tracks rather than falling off.


What is a covalent semiconductor?

Question: Aren't all semiconductors' atoms bond in a covalent bond? How is a "covalent semiconductor" different from other semiconductors?
Answer: No, most semiconductors are ionic.
I'm not sure I've seen the term "covalent semiconductor" before. Wikipedia has an article on covalent superconductors.
I think the main point would be that many if not most semiconductors are inorganic solid-state compounds. Consequently, most of these (e.g. III-V semiconductors are ionic solids, not really covalent ones. Consider GaAs or InP, which are typically classified as ionic.
That is the solid state electronic structure can be considered mainly composed of cations and anions (unlike organic chemistry where the electronic structure is considered mainly of neutral atoms).
(Incidentally, defining whether some of these compounds have purely ionic or purely covalent interactions is somewhat futile, since most bonding interactions are both somewhat ionic and covalent.)
Answer: Most semiconductors are inorganic solids but some polymers can be semiconducting and that is probably what the term "covalent semiconductor" is referring to.
The majority of semiconductor material are inorganic solids (as Geoff Hutchinson describes in his answer). The electronics industry is based on the use of silicon-based materials (often doped with small, controlled amounts of other elements to achieve the precise semiconducting properties required). Mixed compounds like GaAs or InP are also used. Arguing about the nature of the bonding in these compounds is is, as others have said, a little futile.
But there are a range of compounds that can be semiconductors that are more often thought of as "covalent". The most important of these are Organic Light Emitting Polymers (which, in devices, are called Organic Light Emitting Diodes or OLEDs). If the term "covalent semiconductor" means anything, this is the class of compounds it is referring to.
To simplify a little, the semiconducting property is created by delocalisation of electrons along the pi-system in the molecular chain as opposed to by the overall crystal structure of an inorganic solid.
There is a good Wikipedia article on the topic under the title "Organic Semiconductor". These are now becoming significant in display technology.
Answer: Pure silicon (Si) and pure germanium (Ge) are examples of covalent semiconductors. To explain, first take a look at the difference between ionic and covalent bonding.
In ionic bondig, the electron is given by the least electronegative atom and taken by the most electronegative atom. If the difference in this electronegativity of both atoms is rather large (so atom A wants to give badly, atom B wants to take badly), the bond is regarded as strictly ionic.
On the other hand, if there exists a bond between two atoms which have a similar affinity for an electron, the bond is regarded as covalent. This must be the case in pure silicon, as there are no other kinds of atoms present, so there are no different affinities. Silicon has 4 valence electrons and forms a crystal structure, sharing it's 4 valence electrons with 4 neighbors, thus all filling it's orbitals to the maximum of 8 electrons.
Silicon is an intrinsic semiconductor, meaning that without any modifications, some electrons may reach the conduction band. Adding dopants to a crystal structure such as this, can change these semiconducting capabilities. The difference with oxide semiconductors is that in covalent semiconductors, the effectiveness of dopants at a given temperature is solely determined by their ionization energies. In oxide semiconductors, it also depends on the extent of ionization of the structure. After all, the presence of the dopant in an ionic compound (oxide semiconductor) can be partly charge-compensated by other ionic defects. This is explained in chapter 2 of 'Physical Ceramics'.
Answer: A covalent semiconductor is one whose crystal structure contains covalent bonds. A covalent bond is one in which electrons are equally shared between the bonded atoms. Only silicon and germanium are purely covalent because all bonds are identical and thus, by symmetry, electrons are shared exactly equally. Compound semiconductors like gallium arsenide, GaAs, are partially covalent, there is some imbalance to how the electrons are shared in bonds. They spend more time with one of the constituent atoms than with the other one.
On the other end of the scale are ionic bonds and ionic solids where one atom in the compound rips the electron from the other atom. The electron then essentially becomes part of the negatively charged ion. NaCl is such a solid. I can't think of any ionic semiconductors.
In Introduction to Solid State Physics, Kittel has a table of the "Fractional ionic character" of bonds in crystals. Silicon is 0 ionic (meaning fully covalent). GaAs is 0.31 ionic and NaCl is 0.94 ionic. All of the III-V semiconductors are in the range of 0 to 0.4. Some semiconductors like CdS go as high as 0.7.

What is a covalent semiconductor?


How to cook rice for 60 people

Question: I have to cook for 60 people, and one of the things I am going to make is (japanese) rice. Normally I cook it in a rice cooker, or in a pan with an amount of water and let it cook until the water has 'dried up'.
Can I use the same way of cooking rice for 60 people? (Say I have 6 kilos rice that needs to be cooked) how much longer is it going to take me to cook rice this way? What can go wrong? Can I just leave it in the pan until its done, or do I need to stir it because of the big amount?
Comment: Not quite a duplicate: http://cooking.stackexchange.com/questions/7068/cookware-and-methods-for-large-quantities-of-rice
Answer: Three main factors you need to think about is the water ratio, method of cooking and portion size.

When cooking Japanese rice(short glutinous grains) the optimal ratio is about 1:1 of water and grain. Normally when cooking smaller portions you add additional water to compensate for the water that evaporates and turns to steam while you cook so in most recipes you will see recipes asking for 1 cup and a couple extra tbsp of water for each cup of rice.
However you are cooking a very large numbers of servings so the evaporation will be negligible. You can stick with 1:1 ratio.
To cook the rice you can use either a large stock pot on the stove top or put it into a large pan and bake in the oven.
For the first method, you need a really thick stock pot(a thicker pot results in better heat distribution which results in less burnt bits at the bottom). I would recommend doing 30 servings at a time. Measure out the rice and water and bring to a boil. Then turn the flames down really low and simmer with the lid on for 30-45 minutes. Then turn off the heat and let it sit with the lid on for at least 15 minutes.
To make it in the oven, measure 30 servings of rice and water in a large oven safe pan and bake at 325F for around 30-45 minutes. Turn the oven light on and check if all the water have been absorbed into the rice. Using this method I would increase the amount of water to about 1:1.1 of rice to water.
Rice will generally double in volume when cooked compared to its uncooked version. If you are making 60 1/2cup servings of rice you would need 15 cups of uncooked rice. Or if you are going with 3/4 cups per person, you would need 22.5 cups of uncooked rice. 6 kilo of uncooked rice is around 25 cups so your estimation was pretty close to the mark. I would cook all 6 kilo of rice. Its better to have a bit extra than to not have enough.
Comment: It is certainly possible to do all 60 servings in one go but you would need at least a 20 quart stock pot/pan to do so. Breaking it down to 30 servings seems much more manageable. But if you have pots and pans big enough to accommodate that, there is no reason not to.
Comment: Why would you recommend 30 servings at a time? Is it because of the space in the pan , or because its faster and/or less burned rice?
Answer: I've seen this at some take out:
Do this in smaller batches that can be easily handled.
They prepared all the rice in advance and put individual portions in small food and heat safe plastic bags.
I assume they keep it in the fridge until serving time, and when they setup service, they put the individual bags in a steamer.
When it is time to serve, just pop the bag open and set on plate.
Comment: Unfortunately I don't have the option to cook anything it advance, I just have the day itself a few hours to prepare everything (with some help). Otherwise it would have been an option.
Answer: You can't  boil any rice for 30-45 mins, let alone let it sit for another 15 mins while it cooks under it's own heat further. At solid boil, rice is done in max. 10 mins. At boil and steam down, max 20 mins. So with a 40 litre pot, you're gonna need to pre-boil the water, then add rice, and remove fast after 10 mins or so, or it'll cook itself into a mush off the fire after 20 mins (and for the next 5 hours after, till water in pot is cool).
Comment: On the contrary, if you measure out the correct ratio of water to rice, and insure that you are lowering the heat to minimum after its come to a boil, it steams the rice to perfect doneness slowly without risking any burned bits at the bottom. This is especially important since you are dealing with a larger pot of rice. You might run into mushy rice if you are using improper water to rice ratios.

How to cook rice for 60 people


Risk of infection at the gym?

Question: When I dead-lift, I sometimes scrape my legs from the bar threads.  Do I risk getting an infection because of this?
Comment: At the risk of sounding snarky: you should figure out why you're scraping your shins and then fix it!
Answer: Yes, you do. Additionally it will take more than 48 hours for those injuries to repair so it's entirely possible that you'll be pulling the bar across unhealed wounds. It doesn't take much to realize that your blood and body fluids are now on the bar that you put back, perhaps with a towel wipe which doesn't really do much, and now the next person is using it 10 minutes later.
You have a couple of options:

Wear long pants. Personally I can't stand this, but some people have no problem. Make sure they're stretchy or baggy enough to not pinch and change your form.
Wear socks that go up to your knees. This might look ridiculous, but there are some fun socks out there that work well. I have a set with my state's logo on them, get creative.
Use tape. You can bring a role of athletic tape with you, and put two strips down each shin. This is what I do because I can still wear shorts and I can just toss the tape when I'm done.

I've heard of people slicing the plastic from a 2 liter bottle and putting that in their knee-high socks as well who are particularly prone to this problem.
Comment: I never thought of this until I met a lifter who brought his own bar for the simple reason that he could control the cleanliness of it. He bled hard from his shins when lifting.
Comment: @Alec I'm okay with taking my chances with shared gear provided I wash my hands afterwards and don't touch my eyes / nose. But doing something that takes a filthy bar and rips my skin open is a whole different bag of potatoes. That guy bringing his own bar though has the advantage of using the grip knurling he wants, the amount of whip he wants, etc. Can't blame him, especially pulling that much weight.

Risk of infection at the gym?


How to show one variation of one product in a View Pane

Question: I have a View Pane on my home page where I list all products that are in promotion. Each product variation that can be set to "show in promo banner 1" via a taxonomy term field with checkboxes. So the store owner can now tick this checkbox to indicate that this product variation is in promotion. This works but only for product displays that have only 1 variation. When, for example, I only tick this checkbox for "product variation 4" of a particular product and no other variations, the first variation shows with a variation select widget and that's not what I want. So how can I only show that particular variation without the widget but with all the correct data and an add to cart button?
Comment: Can you update the question with info about your Views config and Taxonomy on variations?
Answer: If what you're seeing is the fully rendered Add to Cart form in your View, then what you're looking to do is impossible without custom code. The Add to Cart form is rendered via the field display formatter on your product display node type. It has no way to interact with the configuration or results of a Views query.
You can create a View just showing variations with an Add to Cart button that doesn't invoke the entire form, but doing so will strip the creating line item of the context of what product display that variation is a part of. This means the line item won't link to the product page like it ordinarily would. You could always link it yourself if you know that each variation only exists on one node via a reverse reference, but you'd likely still lose some functionality related to the standard form's normal grouping of variations.
If that's an acceptable trade-off, then you need to recreate your View using Commerce Product entities as the base as opposed to Nodes. Otherwise you're going to have to create some custom Views plugins.


How to force ubuntu touch to be in landscape on Nexus 7

Question: I was wondering how I could force my Nexus 7 to run Ubuntu touch in landscape and have side-stages.
Could anyone help me with this?
Answer: Unfortunately not a very helpful answer, but:
if you want to change it simply by doing some configuration edits it won't be possible. Quite a bit is yet hard coded and therefore it is clearly not yet the right time to start on this level.
Quite a bit of work has to be done till there is a universal configuration to change the individual behaviour like roation or side-stage.
I would say keep listening the different channels, like irc, mailinglist or the wiki and you will see when it will be possible.
Answer: You can use this tutorial http://blog.wellsb.com/post/43774533626/side-stage-on-nexus-7-ubuntu-touch to enable side stage, but it's still in portrait.  I haven't had time to play around with forcing landscape, yet.


How to survive the heat in regions with very high temperature?

Question: I am soon going to visit Las Vegas, and I heard that high temperatures are very normal there. I can't rule out the possibility of taking a walk while it's, say, 39 degrees Celcius. What steps can I take to make this more comfortable? I heard of hydrating, covering the head and wearing appropriate (lightweight and not dark?) clothing, but what else is there to keep myself comfortable?
Comment: I found myself walking way faster than locals during the mid-day heat in Cambodia (though perhaps a bit slower than I normally would). The downside is that I consumed vast quantities of water, little of which came out as urine. I think I would have gotten very ill if I hadn't had all that water.
Comment: http://en.wikipedia.org/wiki/Mad_Dogs_and_Englishmen_(song)
Comment: I am an early bird. It's awesome there in the morning, say between 5-9, when the city is getting awake. I was there in November last year, and the temperatures in the morning are just about right for me. And they are acceptable over the day when you drink and eat enough. A power nap doesn't hurt. Coming from western Germany, I am not used to such temperatures, but because the air is rather dry, it was very enjoyable.
Comment: What kind of walking are you talking? Do you mean walking between casinos or going for a hike?
Comment: More of a hike, I'm probably not planning to leave the city though.
Comment: How hot is where you live? Sometimes it's easier to adapt when it's only 15-20 degrees F of a difference. I've had to *run* in 95 degree weather (Fahrenheit)...
Comment: @AnnonomusPenguin: I live in Poland and the summers are sometimes pretty hot here as well (not as hot as Vegas though - around 30 Celcius).
Answer: Vegas is a dry heat--while this is often scorned by those who don't understand the difference it means that your body can do a much better job of cooling itself than you might expect.  Your body sweats, it very quickly evaporates and you are nowhere near as aware of the heat as you would think.
As others have said, bring plenty to drink--although since you say you aren't going to leave the city you also can travel light and buy stuff along the way.
If you do leave the city tell someone where you are going and when you're going to be back.  If something happens you need search and rescue to be out there promptly.  Note that if you're outside the ring of mountains around the city that cell phones will be iffy.
I would also recommend sunscreen.  The summer sun here is brutal.
Comment: And don't forget a hat. Not a baseball cap, but a light hat with a reasonably wide rim to shield your eyes and neck from the sun.
Comment: +1: Pointing out the dryness. I am more used to a temperature range of [-10°C..25°C] in Germany, often humid. I can tell that 35°C (and eevn more due to window reflections) Vegas heat is more enjoyable than 23°C German humid heat we have right now. Can't tell about 45°C Vegas heat, though (was there in November).
Answer: You may want to look into buying clothing specifically marketed as keeping you cool. I regularly ride my bike 15 km in 30 C heat. In a white cotton tshirt, sweat runs down my arms and I have trouble gripping the handlebars. In a long sleeved "performance " shirt I feel much cooler (even in a dark blue one) and sweat far less. I also drink less water in those shirts. Example: http://www.mec.ca/product/5032-035/mec-rhythm-long-sleeve-womens - I have no affiliation, I own three of that shirt though.
A long sleeved loose shirt, even if it's not a special cooling shirt, may well be cooler than bare skin and will protect against sunburn. You may also be glad of it when you go inside and the air conditioning is on stun.
Comment: Heat in Ontario?  Is the present heat-starved summer unusual?
Answer: I'm resident in Canada and occasionally travel to Dubai to visit my parents. I am in Dubai right now and it was 44 degrees Celsius this afternoon. Note that I am used to wearing shorts even when it is lower than 0 Celsius while in Canada.
Here is what I have for you:
Clothing

Absolutely avoid long sleeved clothing
Wear shorts instead of jeans or other long pants as much as possible
Try and keep to lightly coloured clothes
Some find it helpful to use a parasol if they go for long walks

Diet

Carry fluids (preferably water) with you wherever you go
Don't drink anything that has been left in a car that was exposed to the heat
Las Vegas isn't humid but, in places that are both hot and humid, I find my nose getting constantly blocked,which makes it harder to breath. To avoid aggravating the situation, I avoid going to places that are filled with people that smoke (it is okay to smoke indoors in bars in Dubai)
Heavy meals make me sleepy and lethargic and zap any energy that wasn't already drained. I'd avoid the buffets :)

Exercise

You may consider yourself to be physically fit but remember that your body is not acclimatised to this weather. Know your limits and listen to your body
If you must exercise in the outdoors, do it incrementally. That would give your body a better chance of adapting
For any significant amount of time exposed to sunlight, you should use sunscreen
Comment: The part about long sleeved/shorts is actyally wrong under direct sunlight. People don't roam around in the desert naked for a reason.
Comment: Great answer! +1 A hat always helps, also sunglasses for the blaring heat!
Comment: @DavidRicherby I tried to keep my answer as general as possible as high temperatures often come with fair amounts of humidity...
Comment: @Geeo it depends on a few factors... I find a happy medium with that "athletic" material that's lightweight, allows airflow, but I can wear long sleeves with it and still feel pretty good. It depends on a ton of factors...
Comment: @Geeo long flowing garments are better than short tight garments, but those are still better than long tight garments (especially the ones typically sold in cooler climates, as those are designed to keep the wearer warm, rather than prevent overheating, different materials).
Comment: Carrying water with you all the time is probably the most important advice. I remember a friend telling me how he got lost in a desert-like area once, and the fact that he was carrying a bottle of water (as he was advised beforehand) saved him.
Answer: We are Vegas locals, and love hiking.
If you are going to hike in the hills, take tons of fluids. More than you think. Only because running out, cuts the fun short.
Consider a hike in Mt Charleston. 20-30 degrees F cooler than downtown.
Also consider hiking in Red Rock Ice Box Canyon (hint, hint -- the name).
We like to trail run in the evening, after 6pm. As soon as the sun's off a little, the temp drops. By far my favorite is trail running at night (headlamp). The trails are easy to follow, it's an amazing experience, cooler, and feels like an adventure.
The heat is a dry heat, so it's not the heat that's a problem it's the sun. So if it's an overcast day, it's actually not so bad.
Also the part of town. The hottest is downtown (concrete), and Henderson (oven). Summerlin and towards Red Rock is the coolest. In the shade or early evening, quite pleasant.
The hiking, rock climbing is world class here. Once you leave the strip, it's quite amazing, and tons of groups. There are at least 4-6 hiking meetup groups. Each with 200+ members. There are literally 3-4 organized hikes per day going out, all inside the city, and they know where and when to go to be coolest. So get on meetup before you go, join and tag onto one of the groups. Some of the leaders take you into unexplored areas, other leaders more standard fare. But lots of options, lots of fun.
If you can find a shuttle to Mt Charleston (or rent a car) you won't be disappointed, bring a jacket (you will get cold), 2000+ year old trees, views, etc, etc.
But your best bet is meetup, those hikes tell you exactly what to bring (how much water, jacket if required, etc).
Enjoy!!
Answer: Don't think you can walk at your normal pace when it's much hotter than you're used to. Take it easy and allow longer than you think it'll take to walk anywhere. Force yourself to walk more slowly any time you catch yourself going quickly.
Answer: Hydrate and cover your head, yes. Lightweight clothing, yes within reason but not gossamer see-through stuff. Colour is less of a big deal than you might expect but all else being equal you'll be a bit warmer in darker clothing, so avoid it.
karancan already mentions sunscreen. I find that sunburn is orders of magnitude more uncomfortable than just missing out on the (anyway debatable) cooling effect of showing a bit more skin. As such I treat it as the primary issue above all others.
That's why I prefer long-sleeved and long-trousered clothing. Loose-fitting clothing with a tight-weaved fabric has its own cooling effect anyway since it keeps the sunlight off most of your skin. I may be stereotyping, but for a Slav moving 15-20 degrees of latitude south near mid summer, "significant amount of time" exposed to sunlight is, like, a minute. If you can feel the heat of the sun on you, get sunscreen immediately onto anything that sticks out. Don't forget the hands and the hairline at your ears and neck.
Beware that sunscreen can be rather unreliable if you're sweating a lot or pour water on yourself. Consider waterproof kinds if this becomes an issue. If you have fair skin (and possibly even if you don't) you might as well get the highest factor you can find (if it's not 50 something's wrong) and re-apply according to the directions. Hug the shade, especially initially until you get a feel for even what a few minutes of sun feels like.
Next worst thing after sunburn is exhaustion and sun/heatstroke. Drinking water, hat, dark glasses. Pay attention to your breathing and how your head feels (dizziness or headache is bad, get out of the sun). Expect to walk slowly, drink frequently in small amounts, a bit more than you think you need. Beware drinking very cold water: it messes with your subjective expectations and might make you feel less thirsty than you "should" be.
Pay attention as you go, how much difference the time of day makes. Even if the "officially measured" air temperatures are similar, there's a huge difference between going for a walk at mid-day or late afternoon.
Somewhere down the priority list is how hot you actually feel. In 39 degrees you're never going to feel chilled, especially walking around sun-heated city streets, so to some extent you should just accept you'll feel uncomfortable and concentrate on avoiding anything that will make you feel really uncomfortable (getting burned, vomiting through over-exertion, hyper-ventilating, passing out, that kind of thing).
That said, if you find that you personally feel most comfortable and reasonably cool walking around in the sun in close to no clothes, then sunscreen up and get on with it. Just mind the dress code of wherever you're going! A couple of pairs of shorts doesn't take much packing space in addition to clothing that will cover you, so you can keep your options open.
Doing what the locals do has its merits, but in Las Vegas a lot of the apparent "locals" (a) don't know what they're doing, they're actually visitors just like you, and (b) are kind of pink-looking. So you should only trust what you see around you so far.
Answer: Many others have mentioned the clothing, especially the color. I am also of the long-sleeved fraction, but! I don't think that sports clothing is your best bet. It is made from synthetics, and they cause a bit of greenhouse effect and don't wick sweat that well, despite the manufacturers' promises.
In the really high heat, it's best to wear linen. It has a nice cooling effect. I think ramie will work well too, but have never had pure ramie clothing. Silk can also be quite good, but it's hard to find silk substantial enough to not be transparent without matching the price of your plane ticket. The athletic synthetics come in next, and only after that come thin wools (also rare and expensive), then cotton and kapok (cotton is absolutely terrible in conjunction with sweat), and last of all are everyday synthetics. Loose cuts and light colors are good too. Avoid layers - in a casual situation, it might even be better to go commando under dark colored pants than to wear light pants over underwear.
For the head, don't forget enough shade. Don't just wear sunscreen, you should also be concerned about the visible light entering your eyes and causing all kinds of physiological mayhem beside the unpleasantness of feeling blinded. Make sure you have very dark glasses (category 3 at least, better 4), and a broad-brimmed hat. If you need vision correction (especially if you are myopic, which frequently causes photosensitivity), make sure you don't have to choose between seeing stuff (wearing regular glasses) and feeling OK but going half blind with sunglasses without correction.
Finally, if you absolutely can't stand the heat, here is a trick to use. You need to cool rapidly your blood. This is best done with constant wetness at a place where a major blood vessel comes very near to the skin. The most convenient place is the wrist, where you can measure the pulse. You can even wear sweatbands and keep wetting them. If you don't have a sweatband, but notice the early heat stroke symptoms, use a paper tissue. Wet it copiously and wrap it around the wrist, it will stick there by itself. When it starts peeling off, it's too dry, wet it again.
There is a corresponding point at the ankle, but it is not so convenient to keep wet, and the femoral artery in the inguinal area is an even worse target, and the area is probably already sweating enough anyway. But the other options are prime candidates: the carotid artery and the blood vessels at the temples. The carotid becomes especially important if you are already having a mild heat stroke, because it goes straight into the brain.
It's a good thing to try to pay more attention to your body before you start the journey, so you can tell easier when there is something amiss. Ask yourself explicitly how you feel - tired, hot, etc. - to make yourself a bit more vigilant, and also to learn better what's your usual state. Also try learning to recognize dehydration early - for example, I can dehydrate enough for my lips to chap before I feel thirsty. Once you have done this, you'll be better equipped to recognize potential problems and nip them in the bud using the obvious methods (go inside a climatized building, drink, etc.).
Answer:
I can't rule out the possibility of taking a walk while it's, say, 39 degrees Celcius.

Stay away from being outside for a long period of time when it's hot outside. If you want to explore the city, it might be best to set out early (7:30 AM latest) or in the late evening. From about 11AM-4PM is the warmest time of the day, so try to stay out of the heat then.
I live in the USA where temps range from about 105 to -10 degrees F during the year, and you get used to it. I've had to go outside for gym classes before in the heat in the middle of the afternoon, but it's bearable. Just make sure that you have lots of water. Keep in mind that you should drink hours before AND after you go outside. I often have a water bottle by my computer (where I go after I get home) that is about 3 cups and I drink most of that that within 20-25 minutes or so and fill it back up to keep drinking (at a much slower rate... like pointed out, if you drink too much, it can be unhealthy).

What steps can I take to make this more comfortable? I heard of hydrating, covering the head and wearing appropriate (lightweight and not dark?) clothing, but what else is there to keep myself comfortable?

Remember, dark clothing is dark because it turns all the light into heat. White clothing is the best. Lightweight clothing is nice, but there is another grade of material that's specifically designed for athletics. If you want to try that out, give it a shot. I generally like wearing that material anyway around the house because it's quite comfortable.
If you're feeling lightheaded/showing other symptoms of dehydration, it's best to go into a building somewhere that has AC and cool down, drinking lots of water. Other choices of drink usually negativity affect your hydration levels, so stay away from pretty much anything except pure water. I like adding ice in an insulated water bottle to keep it nice and cool. Note: "Smart Water" isn't usually good since is seems to have no salt in it (unlike most natural water), so you won't have any salt to sweat out...
The last thing I can think of is educate yourself on how to be safe with hot temps. Make sure not to push yourself too hard if you're not used to the heat.
Comment: "I often have a water bottle [...] that is about 3 cups and I drink that within 15 minutes or so and fill it back up to keep drinking." I hope you slow down after the first 15 minutes! Drinking 700ml of water every 15 minutes for any period of time is the sort of thing that can do you [serious harm](https://en.wikipedia.org/wiki/Water_intoxication). The human body is much better at dealing with dehydration than overhydration. Of course, it's best to avoid being dehydrated but don't go over the top.
Comment: @David Yeah, I do slow down. It's more 2/3 of that water bottle in 20 minutes, and when I refill, that lasts me at least two or three hours. I don't drink 288 cups of water a day :)
Answer: Stay hydrated. Be sure to drink lots of liquids, especially water.

Avoid or minimize alcoholic, carbonated, and caffeinated beverages as these can dehydrate you.
Drink more than you think you need. You need to replenish the liquid removed by sweating and sweating is a key part of keeping you cool.
Persons who have epilepsy or heart, kidney, or liver disease; are on fluid-restricted diets; or have a problem with fluid retention should consult a doctor before increasing liquid intake.
If you're sweating a lot, be quick to replace lost salts and minerals as well as water. Fruit juice or sports drinks with electrolytes are good choices, but do not take salt tablets unless directed to by your doctor. Taking calcium supplements, however, is a good idea.
Drink cool (but not icy cold) liquids to help lower your body temperature. Try to keep water refrigerated prior to drinking, if possible.
Eat lightly. Hot foods and high-calorie or high-protein meals raise your body's metabolism and its temperature, which is the opposite of what you need to stay healthy during a heat wave. Think fresh fruits and vegetables, cold salads, etc. and be sure to eat light, well-balanced and regular meals. Some good things to try would include:

a fruit salad
a salad
a watermelon, mint, and raspberry salad
healthy snacks
Spanish gazpacho.

for more :http://www.wikihow.com/Survive-a-Heat-Wave
Answer: I agree with all the other answerers about clothing and water. A simple way to cool down is to wear wet clothing. So, you bring extra water with you and keep your clothes wet by spraying it on your clothes. The more water you can evaporate off your clothes this way, the less water you lose in the form of sweat. The advice given by Bear Grylls in an episode of "Extreme Survival" on Discovery channel is to use urine to make your clothes wet as that saves precious drinking water, but I don't think lack of water will be a problem in this case.
You need to bring enough food with you. Eating enough will also help to prevent water poisoning.
You need to pack warm clothes, in the evening temperatures may go down fast.
Comment: I do not think water poisoning is a big threat in Vegas. And as a general surviving tip, don't forget that digestion use a lot of water (on the other hand, so does starving).
Answer: In addition to all the previous answer, I am often shocked to realize how many people don't understand how to use a fan.
I heard many people saying it is useless if it blows warm air. That is, of course, 100% wrong.
As mentioned is previous answers, sweat evaporation is the key for surviving.
Sweat evaporate easily on naked skin in dry warm air. It does not on clothed skin or in humidity saturated air.
Of course, as you sweat, the air immediately around you get humid. The role of the fan is to blow away this humidity so that you still are surrounded with dry air.
So, as long as you are in a closed room with no ventilation, it doesn't matter much if you wear long of short clothing. But as soon as there is a gasp of wind, GET NAKED! With sun block if needed.
In desperate situation, get soaked wet. Even better if you wear long clothing. If there is absolutely no wind to evaporate all that water, just walk to generate that precious breeze. If you walk in the desert and regularly pour water on your head and your clothe, you are more likely to get a cold than a heat stroke
Answer: Wear white clothing. Wet a towel or a cloth with water and put it over your head and put a hat or cap over your head.
Comment: I actually find a wet towel wrapped around the neck works better.  They sell water absorbent wraps for that purpose.


Using grammars to extract bibliographic citations

Question: My task lays in the area of text mining / labelling, more particular extraction of bibliographic citations (references) from the plain text, as shown here:

Basically, for the input text the algorithm should recognize:

The beginning and end of citation
Journal name, title, author, issue, volume, pages

This task was already approached in e.g. Citation Parsing Using Maximum Entropy and Repairs (Ng Yong Kiat, 2005), which demonstrated that CRF models deal better then MEMM or pattern-based approaches. Currently there are two projects, that do the job:

ParsCit, a Perl program build on the top of CRF++ project
Grobid – Java module, also based on CRF++

While the results of mentioned approaches are already known (and are very good), I was given a task to do the same but using the context-free grammars. Indeed, the information looks to be very structured but I am not sure if this approach can outperform CRF on sensitivity, at least I hope it can beat it on accuracy.
My idea is the following:

Define the fixed grammar rules for already known types:
YEAR → (19|20)\d\d | \d\d\d\d
PAGE → \d{1,3}\-\d{1,3} | e\d{1,3}
ISSUE → \d{1,3}
It is possible to infer from training set the probabilities of rule alternatives e.g.:
PAGE → \d{1,3}\-\d{1,3} with P=0.8 | e\d{1,3} with P=0.2
From the pre-annotated training set generate the high-level rules (all chars between non-terminals are terminals):
CITATION → AUTHORS, JOURNALTITLE, ISSUE, PAGES, YEAR | AUTHORS, BOOKTITLE, VOLUME, CHAPTER, CHAPTERTITLE, EDITORS, PUBLISHER, PUBPLACE | ...
CITATIONS → CITATION | CITATIONS; CITATION | CITATIONS; and CITATION

The problematic places are:

AUTHORS: There is no fixed rule for them, but one can write a function, that can score that the given text looks like an author. Also the list of possible (English) surnames is not so huge, but if I create the thousands of rules it will slow down the grammar parser. Let's say for authors we have some scoring function, that for given input returns a number [0 .. 1] reflecting how the input really looks like an author. The grammar parser should feed all possible variants for AUTHORS and stop on one with a best score.
JOURNALTITLE: The same story. There is obviously no general rule to define it. There is a list of all journals, but then comes also the subproblem of abbreviation: Ann. NY Acad. Sci. = Ann N.Y. Academy Sci = Annals of the New York Academy of Science. Again, we can define a scoring function for that; in worst case the function can measure the distance between input sting and all known journal titles using Damerau–Levenshtein algorithm.
The text like "Vol", "Chapter", "edited by" can be very useful as terminators prefixing the corresponding values (and thus reducing the ambiguity of the grammar), but can they be identified and learned automatically?
The same for terminators before and after citation, which can be very useful (perhaps will speedup the parsing):
SUPERCITATION → ( CITATIONS ) | ( see, e.g., CITATION ) | see, for example,  CITATION | described in, e.g., CITATION | is disclosed by CITATION
Does it make sense to "hardcode" them or try to learn them?
The "noise" text between citations: how to deal with it?

The goal of the lexical analysis is perhaps not to find the most probable parse tree, but also to maximise AUTHORS and JOURNALTITLE functions.
Can somebody advise me:

If SCFG is the right way to approach the problem? If yes, how is it possible to adapt this approach to create a parse tree based on probabilities and also on scoring functions?
Are there any other relative works / articles?
Are there any libraries that can help in chunking the text (written in a way that can be applied also for e.g. Chinese text)? I have found some monsters like UIMA, Mallet, MinorThird... I wonder about your personal experience when using them for the task like above.

Thank in advance for any reply.
Answer: One of the starting points you should look at is Proper Noun recognition and Tokenization. One of the well known papers is this one, and also a lot of new submissions into ACM have dealt with this problem. This will help with in-line citations.
Comment: You can add either a comment (via `add comment` under my post) or add the answer, if you think your idea is mature. May I ask you: how do you think the noun detection will help in my case? I do not deal with natural language recognition, but on the other side the part I would like to capture is inside the natural language stream.


Calculating fourier transform at any frequency

Question: I know that if we have some data representing some wave, for example image line values, we can use fourier transform to get frequency function of that wave. But we have N values at points x=0...N-1 And we get only N frequencies at the output. So I want to analyze the wave everywhere in the range [0, N-1] For example at point u = 1.5. How can I do it?
Answer: You need to have some a priori knowledge about your wave between and beyond the sampling points to get a meaningful guess about the full Fourier transform. The $N$ values that you get doing the discrete Fourier transform have anything to do with the continuous Fourier transform only for indices much less than $N$. Note that different assumptions will lead to different answers for large frequences. If you need only relatively low frequences, your signal is compactly supported in time, and your sampling points cover the entire support, you can safely interpolate the values of the discrete FT to guess the continuous one but there is no way to get reliable high precision values for the continuous Fourier transform at frequences comparable to $N$. The $N$-point resolution on $[0,1]$ is just not high enough to catch those frequences without an error.
Also note that you want the frequences not on "on the interval $[0,N-1]$" as you wrote, but rather on the interval $[-M,M]$ where $M\ll N$. For decent signals, the frequences with indices close to $N$ in the discrete $FT$ actually catch the negative low frequences in the continuous FT, not the high ones.
Answer: Strictly speaking, you can't. That is, you have to interpolate to do it, and to do that in a meaningful way requires some knowledge of the problem domain. However, the easiest way to do so is to note that the given function is naturally written in terms of its discrete Fourier transform as a trigonometric polynomial, so you can just go ahead and evaluate that trigonometric polynomial at any intermediate point. The same thing goes with the function and its Fourier transform interchanged, of course. Though it does not really make good mathematical sense to do this interpolation in both domains simultaneously.
Answer: If what you need is a simple practical method to do the interpolation,
then just multiply the "time domain" samples by the linear-phase
signal $\{\exp\left(\alpha\cdot i 2\pi k /N\right)\}_{k=0}^{N-1}$, where
$\alpha\in(0,1)$ is the sub-sample shift in the "frequency domain."
(I'm not sure if an additional constant of absolute value 1 is
required here). As
already noted in previous answers, the motivation for this is the
assumption that your samples vector $\{x_k\}$ comes from sampling some
continuous-time signal $\{X(t)\}_{t\in \mathbb{R}}$, as in
$x_k=X(kT_s)$ for $k=0,\ldots, N-1$, where $T_s\in \mathbb{R}_{++}$ is
the sampling period.  If the continuous-time signal has a compactly
supported Fourier transform, than by Shannon's sampling theorem $X$ is determined by the infinite sequence $\{X(kT_s)\}_{k\in
\mathbb{Z}}$ for small enough $T_s$.  Since we only have $N$ entries
of the infinite sequence, we loose some information on $X$.  But if
$X$ decays rapidly (rather than having a compact support), then at
least intuitively we don't loose much (I know that this is a dangerous
and imprecise statement :) ).
For example, try the following Matlab lines:
ttt=-32:31;
x_time=exp(-ttt.^2/10);
figure;plot(x_time);
x_freq = fft(x_time);
figure;plot(fftshift(abs(x_freq)));
figure
for alpha=-4:0.5:4
x_time_2 = x_time .* exp(2 * pi * i * (0:63)/64 * alpha);
x_freq=fft(x_time_2);
plot(fftshift(abs(x_freq)));
axis([26,37,0,10]);
grid on;
pause(1);
end
Answer: Here is one answer from the electrical engineering(or, image processing) point of view. However this answer much non-mathematical and more for practical illustration. Since this is a non-mathematical answer, I have made it community wiki so that I don't get reputation.
In digital signal processing, you sample an analog signal into digital encoding, and let your microprocessor work with it. When you do sampling, you clearly lose some information and there is no way you can recover it. When you become too greedy and actually try to get more, the problem of "aliasing" will happen.
Here is the wikipedia link for aliasing.
For image processing, situation is even better for an illustration, since you can actually see wavy patterns. These are called Moiré patterns, and you must have seen it sometime in the real world. Here is a wikipedia link.


Indefinite article in title of thesis

Question: I am writing my thesis, and the title goes as follows "A study of data mining techniques for ...".
I wonder if it would be better to omit the indefinite article "a" in the title, i.e. "Study of data mining techniques for ..."
Perhaps both titles are correct, but probably one of the two is more appropriate (but I don't know which one because I am not a native English speaker).
Comment: Consider a plural. If you're planning different chapters on each technique, then _Studies in Data Mining Techniques ..._ is a possibility, and doesn't guarantee complete coverage. (I admit I'm prejudiced; my dissertation was titled [_Studies in English Generics_](http://www.umich.edu/~jlawler/dissertation/).)
Answer: For a title, "A Study of..." sounds better and Google Books seems to yield many more results for it than for "Study of..."

Book titles:

A Study of War
A Study of Humor
A Study of Maia Art
A Study of Creation
Answer:
A Study of Data Mining Techniques

suggests a description of a study somebody has undertaken, including the results.
.

The Study of Data Mining Techniques

suggests a description of how we can study data mining techniques. The subject is not data mining techniques themselves, but rather it is how we can study them. Perhaps you read such a book prior to your own study.

Study of Data Mining Techniques

could very well be taken as synonymous with The Study of Data Mining Techniques.
If your article is about an investigation you have performed into the subject of data mining techniques then it is better to include the indefinite article.

Indefinite article in title of thesis


A synthetic sieve organ known as kliver?

Question: in this video at 5:28, the narrator talks about a "vat-grown all-purpose sieve organ" called Kliver that would do away with both liver and kidney transplant. But i don't seem to find online resources about the same. Is that terminology popular in scientific literature, and if so, how would synthetic biology accomplish that? articles about the same will also be appreciated.
Answer: This term is used in this book (Synthetic Biology, The National Academies Keck Futures Initiative, p.43). This book is a summary of several interdisciplinary team discussions during a  conference held in 2009.
One...

[...] team considered building artificial organs. Engineered to be hypoallergenic, these could allow for a mass production of personalized organs. Their novel and broad functions could also be useful for medical testing. In a single artificial organ, one might screen potential drugs for both toxicity and permeability.
For instance, group members proposed the idea of a "kliver", a kidney-liver hybrid. An independent "kliver" could help filter bio-compounds out of drinking water.

There are some more paragraphs revolving around the question how to build a "kliver" and a final paragraph concluding that enough necessary building blocks were available and researchers could start working on it:

Potential building blocks might be mammalian and microbial cells and their products, such as slime, fibers, small molecules and proteins. The cells might be engineered to hold new electrical, mechanical, and chemical powers.
  [...]
  Cells would be programmed to degrade their organs and DNA if they began to invade other organisms or the environment. A genetic "kill switch" aims to stop contamination or infection.

Summarising this, I wouldn't call it a "popular term".
Comment: PS: to share some Google-fu: the book popped up when searching  for "kliver kidney liver"
Answer:
How would synthetic biology accomplish this?

We already have a synthetic kidney. We've had it for over 50 years. It prolongs life, but still not very well. Transplant, with all its challenges and complications, does much better.
The liver is much more complicated, and I would be very suspicious of anyone who thinks of it as primarily a sieve or detoxifying organ being able to build a synthetic liver. It certainly does some of those things, but it does much more, playing an important role in digestion, metabolism, protein synthesis, excretion, and the immune system. See Cecil Medicine Ch. 148 for an overview.   There's a reason we don't yet have a synthetic bridge to transplant for liver failure. I wouldn't rule it out, but I think you'd need to be able to build a synthetic liver before you could build a synthetic kliver.


How was love able to transcend the dimensions of time and space in Interstellar?

Question: How was love able to transcend the dimensions? And how were THEY (people from future) actually able to communicate?
Answer: The main theme of Interstellar is that love transcends the dimensions of space and time. Space means distance. We love a person distant from our location, like a friend studying abroad. With respect to time, we love people who have passed away. We go back in time to love their memories. I don't know if love can move forward in time. Maybe feeling love for expected newborn.
They built a 5 dimensional space based on the relationship of love between Cooper and Murph. They gave each moment a separate room (space) so Cooper can go to whichever moment (time) between him and Murph and try to communicate the means to save humanity.
Answer: Love, as used in the movie Interstellar, is an emotion that transcends the third dimension. It is described as existing in the fourth dimension. Because of that. it can escape the time-space continuum.


SQL Server Express 2005 cannot connect

Question: I have a SQL Server Express 2005 install on a godaddy virtual terminal which currently is only connected to(locally with mgt studio) every few days or so.  Every time i try to connect I get a cannot connect to SQL Server error and after a restart it I can connect just fine locally. I was wondering if there is a timeout setting or something that I am missing that I need to change so that if it is not connected to for a while it does not required a restart?  any ideas? thanks!
Answer: Sounds like you may have the database AUTO_CLOSE property ON.
See Setting Database Options
Answer: As @John Sansom says there is an AUTO_CLOSE option, however from memory (it's an Express feature which I don't use often) I think this only causes a single database to be unloaded from memory.  You can tell if the database is being unloaded (and re-loaded on demand) by looking in the Application Event Log.
Since Management Studio by default will try to connect to the master database which isn't unloaded though I don't think this is your problem.  Again, I'd suggest looking through the event log to see if there's anything obvious in there?  I assume that when you can't connect the MS SQL service is still 'running' ?

SQL Server Express 2005 cannot connect


Searching personal account questions

Question: Is there a way to search for something that exists in just the questions I have posted on Mathematica Stack Exchange?
Comment: Yes, use `user:5183 is:question` as additional search terms. You can find the userID in the link to a user's profile. This should probably be in *Meta* though.
Comment: If you want to search just your own contributions, you can also use `user:me` as a search term. Further syntax: [How do I search?](http://mathematica.stackexchange.com/help/searching)
Comment: @Marco, looks like an answer to me. :)
Comment: @MarcoB Awesome! That works just as I needed. It's going to be helpful.
Comment: @MarcoB Even shorter: `user:me is:q`
Comment: @J.M. Good point (-: Converted.
Comment: @halirutan Didn't know about the short form; thanks for pointing it out. I added it to my answer below.
Answer: Let me summarize what I said in the comments.
In order to search within a certain user's posts, you can use their user ID together with the user search key in StackExchange's search. You can get the User ID from the link to the user's profile in any of their posts.
For instance, hovering over David's name at the bottom of his question above shows that his user ID is 5183, so using user:5183 will return all his posts (questions and answers; the link performs a search on the main MMA site).
The user ID is shared between each site and its Meta counterpart, but not throughout StackExchange, so the same user will have different user IDs on e.g. MMA.SE and math.SE.
If you wants to search your own contributions, you can also use the simpler form user:me or user:mine as a search term.

You can also differentiate between question and answer posts by using the is: tag in search:

is:question or is:q for questions only
is:answer or is:a for answers only

Thanks to halirutan for mentioning the single-letter short forms above!

Here are a few examples of search tags that I find myself using very often:

created:1d.. will list posts created in the last 24 hours; the function also takes closed ranges, and specific dates.
hasaccepted: (y/n) shows questions that have/do not have accepted answers.

For instance, I recently used the following search string to locate questions from last October that had people had found interesting (score=5 or higher), that were not duplicates, that were still open (closed:no migrated:no), that had not been tagged as bugs (-[bugs]), but that nonetheless had not received any answers:
-[bugs] created:2014-10-01..2014-10-31 is:question
duplicate:no closed:no migrated:no score:5.. answers:0

For further search terms, take a look at this page: How do I search?

Searching personal account questions


Can command line arguments be masked or hidden instead of appearing in the process list?

Question: I have written a command line application in C++ that is used to access an online user account via a SOAP API. In order to avoid having any login details written to file anywhere on my machine for security purposes, I decided to write the application as taking the username and passwords as command line arguments. I then found that upon running a ps -aux command that those sensitive arguments are actually visible in the process list. Is there anyway that these can be masked? I am probably being overly sensitive about the security aspects here but I would like to avoid this data being accessible in any way.
If not, are there any other options available other than using encryption algorithms to decrypt this data from a file or passing in encrypted command line arguments?
Answer: The kernel maintains internal pointers to the start and end of the arguments array in the process address space. So, you have to do it in tricky way.
You will find a brief explanation here.