Answer to a closed question

Question: I'm interested in the following question:
https://math.stackexchange.com/q/1851713/84976
and I'd like to provide an answer.
The problem is that the question has been closed (maybe before the last edit it wasn't clear).
What can I do? Should do I ask the question newly by myself?
Comment: Since this particular question was posted just a few hours ago, maybe you could leave some time for the OP - it is possible he will improve the question and that will lead to reopening. In fact, you can help the OP - if you post some kind of hint in a comment, perhaps they will be able to find at least partial solution - which is one of the possibilities how to [provide context](http://meta.math.stackexchange.com/questions/9959/how-to-ask-a-good-question#9960). (Notice that four users chose *missing context* as the close reason.)
Answer: First: The question was closed for lack of context and I completely agree with this closure. Part of the purpose of closing questions is to prevent more answers to be added.
That said, I agree with the comment by Martin Sleziak above. I would say to leave it as is for some time. Give the OP an opportunity to add context to the question. If this doesn't happen within a day or two, I would find it completely fine to repost the question with context. I suggest adding a link to the closed question and explain your reasoning for your interest in the question. While many of us don't like questions without context, there is still some discussion on what exactly constitutes context. IMO you can in this specific case provide context by simply explaining where the question comes from and why you find the question interesting. Please also say in the question that you plan to answer the question yourself. (You can post the answer at the same time you post the question.) That way people will know that you aren't just trying to get someone to do your homework.
Comment: @MartinSleziak: And even if you do answer it at the same time, I would still recommend mentioning in the question that you are doing this.
Comment: Re: *Please also say in the question that you plan to answer the question yourself.* There is also a possibility to post a question and the answer at the same time, see [here](http://meta.math.stackexchange.com/questions/4286/recently-rolled-out-se-encyclopedia-feature).
Comment: @Thomas Why? Imagine someone two years from now having the same question. They type some keywords in a search engine and they find the question. It turns out the question was self-answered. Do they care whatsoever so long as the answer is good? Nope. If anybody has any doubt that the OP is trying to get people to do their homework (something largely irrelevant if the question is of good enough quality), then they can simply see that the asker and the answerer are the same user.
Comment: @NajibIdrissi: I doubt that most people look at who answers the questions. I rarely look at who answered the question before I decide what to do. Anyway, with the hostility towards homework questions and questions without context, I think this *might* be a small thing that could help cause less friction. It is just a short sentence that one can add. You are, of course, free to disagree.

Answer to a closed question


How to reference studies mentioned in a paper without having to read the original papers?

Question: I'm review the literature at the moment. Now I'm reading a paper that mention other studies. How can I reference them without reading the original papers?
Comment: **Don't.**  Just read the original papers.
Comment: I'm starting to notice a pattern in your questions ... they're all about seeking any shortcuts instead of doing a thorough literature review. This is a very bad strategy, that risks leaving you with patchy, incomplete, incoherent knowledge.
Comment: Possible duplicate: [What's the correct way to cite a paper cited by another paper?](http://academia.stackexchange.com/questions/1922/whats-the-correct-way-to-cite-a-paper-cited-by-another-paper); there is also a cross-style review of indirect reference at http://academia.stackexchange.com/a/7776/5920.
Comment: Related: http://academia.stackexchange.com/q/13305/64
Answer: Let us assume, for example, you read Doe (2011) and find Smith (1966) referenced therein. Technically, you can say something like "Smith (1966, cited in Doe, 2011)", or alternatively "(Smith 1966, cited in Doe, 2011)." The exact format depends on the format of the journal (it is also possible to phrase it "cited by" instead of "cited in").
That said, however, it is very dangerous to provide such quotes since you do not know if the person(s) citing the paper has understood it correctly. It is not unheard of that people cite for very odd reasons and not double-checking works cited may just propagate such errors.
So, it is possible but not recommended.
Comment: I'll just leave this here... http://xkcd.com/978/
Comment: If you are using the American Psychological Association (APA) style, the secondary source is listed in the reference list and the primary source is not. (See, for example, http://apa.org/support/publications/apa-style/secondary-sources.aspx). So if Doe (2011) cites Smith (1966), then Doe (2011) should be in the reference list while Smith (1966) should not.  For more on the APA style, see also http://blog.apastyle.org/apastyle/2010/05/secondary-sources-aka-how-to-cite-a-source-you-found-in-another-source.html
Comment: now it is clear. but in this case do I have to put Smith (1966) in Reference List?
Comment: Both should be in the reference list
Answer: If it is relevant to your work, why wouldn't you read them? If they are not relevant, why would you cite them?
The only case I can think where it might make sense is if you are reading a review paper, and want to actually cite them as a collection rather than individually. Because there are a large number or for other reasons. Then you would write

Doe et al. collected in their recent reviews a large number of earlier work in (Doe, 2012 and references therein)

or

Doe et al. collected in their recent reviews a large number of earlier work in (Doe, 2012 and references 15–73 therein)
Comment: "If it is relevant to your work, why wouldn't you read them?"  One possibility is that a copy of the work is very hard to obtain, for example, it could have been published a hundred years ago in an obscure foreign journal.
Comment: It's also possible that the primary source is a personal correspondence.  Or when the secondary source converts the technical language of the primary source into layman's terms.  See http://blog.apastyle.org/apastyle/2010/05/secondary-sources-aka-how-to-cite-a-source-you-found-in-another-source.html
Answer: I wrote a post on writing literature reviews in psychology.
Here's my advice:

Cited In: Good literature reviews do not use "Cited in". Literature
  reviews which summarise Author B's citation of Author A's work write:
  "as Author A (1999) says as cited in Author B (2002) …" . However,
  good literature reviews, when they see that Author B cites Author A,
  go and get Author A's article, read it , and draw conclusions about it
  directly.

So it is only in rare occasions that you need to indicate that an article was cited by another author. Just because you learnt about a study because it was cited somewhere is generally not relevant. Read the original so that you know enough about it to incorporate it into your literature review.
Of course, there are many less common exceptions where you may wish to indicate the relationship between two papers:

You want to discuss how Paper 1 uses Paper 2. For example, you might want to draw attention to how various papers have mis-used a citation in order to justify some misguided methodological practice.
You are performing a meta-analysis and you want to indicate that you used a previous study to find references.

There is also a potential plagiarism issue around over-reliance on a single paper to generate your literature review. If for example, you took 95% of your references from the one paper, this would be questionable in general, but at least by using "cited in" you are being honest. Of course, I think this strategy of reviewing the literature should be avoided in general.
More generally, finding literature by following the citation trail backwards (by looking at references) and forwards (using tools like Google Scholar) forms part of a general set of strategies for finding literature.
Answer: As JeffE above said, "Don't". When you make assertions in your published work, they should be based on either

Something that you have demonstrated yourself in the work
Something that another person has demonstrated (so you cite them)
Something that is sufficiently well known to the intended audience that no citation should be necessary (you don't need to cite Newton for his law of gravitation for example)

To consider the bigger picture for a moment, something that is published does not suddenly become a part of scientific dogma, even if it's published in a top tier journal. The motto of the Royal Society is "Nullius in verba", that is, "take nobody's word for it". If you are relying on established results for your work, then reading these results is the very minimum you should do. In an ideal world where you would then proceed to replicate the results that you are depending on.
Of course, this is usually not practical because of constraints on your time but at the early stages of your studies you should at least consider replicating some results since:

It will give you a far greater familiarity with the domain
There's a very high chance that you will expose some misconception that you had held about the work you are citing
There's a reasonable chance that you will expose a deficiency in the original work

In closing, you should consider that every time you publish something, you have added to mankinds knowledge. Every time you cite a paper without reading it, you dilute that knowledge.


Is there a way to start a workflow through an infopath button?

Question: So let's say I have a submit button that I want to send a workflow email, how can I have it send the email once the submit button is clicked in infopath?
Answer: If your submit button operates in the standard manner (i.e. submitting saves the form to the library or list) then you would simply need to change the start up behavior of the workflow.
Open the workflow in SharePoint Designer and under "Start Options' on the workflow's home page, remove the check from "Start workflow manually...". Be sure the check either "Start on create..." or "Start on change...". In your case I think you would use "Start on create...".
Answer: If you're submitting your InfoPath form to a Form Library, create a workflow attached to this list (form library) and set workflow action to start automatically when an item is added/modified depending on your situation.
Chooose Email action to send emails.
If you want your form to be state aware and send different emails depending on state, create a hidden (state) ineger on form, increase its value on each submit and perform conditional checks on this state variable from your workflow before sending different emails.
You can also keep the same file name across multiple submits of the same form.


What does each flag reason mean, and when should I use them?

Question: I'm ready to dive in and help the moderators weed out content which requires their attention. What does each flag mean and when is the best time to use it?
Comment: @TomBrossman We only have the ability to manage the first section of FAQ, which is why we maintain a list of additional items in the [tag:faq] tag
Comment: This is fairly out of date; that said, we have an 'updated' idea of what each flag reason is and what we, the moderators, expect from them, [here, at the "How do I flag correctly" question on Meta](https://meta.askubuntu.com/questions/15888/how-do-i-flag-correctly)
Comment: Quite a bit of overlap here with the [existing FAQs](http://askubuntu.com/faq). Any plans to merge or copy these answers with the Ask Ubuntu FAQs? Good info on both pages and it may be better to have it all in one place.
Comment: @MarcoCeppi What about comment flags? Any plans to include them here?
Comment: @ObsessiveFOSS didn't think of those, I'll add them in a bit
Comment: Informally, is http://askubuntu.com/a/160006/54298 flaggable on the grounds given in my comments? Editing would go against the last "How to Edit" point.
Comment: @ObsessiveFOSS in this case, yes, candidate for deletion. It's not an answer and could be edited, but there's so much editing that you'd end up re-writing the whole answer. "I googled this" is not a solution, but it definitely at least needs a down vote.
Answer: Doesn't belong here, or it is a duplicate
This is only available on posts that are "questions". Users who have close vote powers already know what this menu and it's options look like. However, those who have not seen what the close vote screen looks like may be slightly confused as to what this is. When you select this option a second menu appears that presents you with the following options:
Exact Duplicate
Rather self explanatory, place the duplicate question in the box.
Off topic (OT)
There is wide range of off topic criteria:

CRITERIA!

Not constructive
Not a real question (NARQ)
Too localized
Answer: Not an answer
The not an answer flag can only be associated to answers themselves (and not questions). Flagging criteria differs from scenario to scenario but the end goal is almost always post removal. Keep this in mind when flagging.
Use this flag when one of the following criteria is met:

An answer is blatantly wrong and potentially harmful or dangerous to run.
The answer is actually a comment which needs to be moved to the appropriate post
The answer is instead another question which needs to become it's own separate post
Instead of editing a post, someone has posted an edit as an answer and it needs to be merged in to another post instead

If an answer is just a "poor" answer (not very detailed, little perceived value, or you feel the urge to flag as not an answer when it does not fit the above criteria) then you should down-vote that answer instead of flagging it.
While some corner cases may exist that aren't covered above, those are the majority of cases that fall under this flag.
Answer: Very low quality
This answers content is not understandable or translatable, it can't be saved with editing or offers little to no solution at all.
This flag is designed to be used not because a post is "bad", but because it can not be saved at all. As a rule of thumb, if you flag a post because it needs to be edited, you should be editing it instead of flagging it.
This close reason also overlaps Not an answer in that if a post has no real solution (no real solution as it does not offer any support or solutions, not necessarily that the solution isn't optimal or a solution isn't exactly what the author is looking for) then it might as well be flagged as very low quality.
Answer: It is spam
This flag reason is pretty straight forward, with a few caveats. Spam is pretty easy to spot. Obviously purchasing Lucky brand jeans will not answer your questions about Ubuntu, if you see one of these posts use this flag reason instead of the "not an answer" flag reason.
The only caveat is with self-promotion. Self-promotion is allowed on the site to an extent. First the post must identify this is a solution they've created or work for, secondly they need to provide more than just a link (that is, either an abridged version of the solution, or a brief explanation of how to apply the software to fix the question asker's situation).
Answer: Not welcome in our community
While some may derive this to mean posts about things that are Offtopic this flag is designed for posts that do not fit within one of two rules.

Violates the "be nice" rule
Violates the Ubuntu Code of Conduct

If any posts break the content of these two covering rules on the site the post is not welcome in this community. Depending on the severity of the offense, the post will at a minimum be removed and the user may encounter any number of actions including and not limited to suspension or permanent ban.


How do I get these virtual domains working in Tomcat?

Question: im new to ubuntu and tomcat moving away from windows and iis to create a website on AWs.  Im having problems trying to replicate what had running on my windows machine. I hope someone can clarify the following.
I've setup the following virtual domain;
dev.sitename.com
devimages.sitename.com

in my tomecat/conf/server.xml file i've setup the following one for each of the above virtual domains;
<Host name="dev.sitename.com" unpackWARs="true" autoDeploy="true" >
    <Context path="" docBase="/home/webapps/workspace/www_sitename_com/WebContent" debug="0" reloadable="true"/>
</Host>

problem i getting is that i cant seem to have both domain running simutiously as i did when running on IIS7. I dont understand why i can only run one instance of tomcat. Also if im viewing on of the above url's and i want to visit stackoverflow.com it stops the tomcat server. I dont understand why this is happening and how i can go about resolving this.
Answer: I managed to get multiple instance working follow this link if you are looking to do the same.


Is the Interactive Brokers API suitable for hft?

Question: By HFT here I mean anything with holding period less than 5 to 10 minutes.
Any empirical/anecdotal evidence of using it successfully on even higher frequencies?
Comment: defining hft as anything less than 5-10 mins is not typical in this industry, cause that could also refer to day trading just a few names which no one i know would refer to as hft.
Comment: possible duplicate of [What is best trading API for hft](http://quant.stackexchange.com/questions/324/what-is-best-trading-api-for-hft)
Comment: IMO, that other question cannot be answered so I'm voting to close.  This question has an answer, so we can leave it open.
Comment: by HFT you mean intra-day trading which Yes it is feasible for
Comment: There is a discussion here about Interactive Brokers: http://www.linkedin.com/groups/Interactive-Brokers-Traders-Fund-Managers-4932221
Answer: I'll just add that with Interactive Brokers you have to be aware of their cancel fees. Remember, Interactive Brokers owns Timber Hill, a very large and active market maker. They will discourage you from competing with Timber Hill through monetary disincentives, among other things.
For example, if you send a directed order (i.e., you don't allow IB to SMART route it), that order will be subject to a cancellation fee. See: http://individuals.interactivebrokers.com/en/p.php?f=otherFees, specifically the Stock tab.
You'll notice a $0.12 fee for cancelling or modifying directed orders. This is outrageously high and completely eliminates any HF strategy, even if the latency, market data, and other issues raised in the other answers were non-existent.
IB is not interested in HFT flow. They make their money in other ways. Automated traders that choose to use IB are best off letting them route with SMART and accept/embrace the fact that Timber Hill will get a chance to internalize the order.
Comment: Who said anything about quote stuffing?
Comment: Sorry, you've apparently missed the point entirely. Please re-read my answer. IB imposes significant fees and restrictions on directed orders. If you're using SMART, you're not a high-frequency trader.
Comment: You can't use directed orders with the cost plus plan. If you're not directing your orders, you're not a high frequency trader.
Comment: I guess what @asianskills meant was even in HFT with all directed orders, one should not be frequently canceling orders. However, modifying orders is inevitable
Comment: Do not make confusion about quote stuffing and trading. Quick trades are fine with IB (even about half second). If we are talking of quote stuffing that is an abusive practice which is being banned by all exchanges, and there are fines up to $1M for such (nonsense and NON profitable) actions which are bordering a DOS attack. See this group for more info too: http://www.linkedin.com/groups/Interactive-Brokers-Traders-Fund-Managers-4932221
Comment: If one is not quote stuffing, IB API are fine. One can have trades which last less than half second or even less (I execute (receive the fill even back) normally from overseas in 50 milisecs from home). If someone's doing something quicker than that to me is quote stuffing. Each cancellation must be accounted for when colocated (Exchange rules), and even the process of waiting for a cancellation confirmation and recording a cancellation would take some time. So for any kind of meaningful trading IB API are fine. The rest is mostly non sense and legends spread by people who do only backtesting.
Comment: You need to use the "cost plus" plan. And actually trade.
Answer: Holding period and trade frequency are two different things.  If you have a high trade frequency, the name of the game is negotiating lower commissions.  That being said, the TWS API gives you the same quality feed as you get using TWS itself.
From Article on HFT Provided by Dirk Eddelbuettel in this question about HFT:

High-frequency trading (HFT) is a subset of algorithmic trading
where a large number of orders (which are usually fairly small in
size) are sent into the market at high speed, with round-trip
execution times measured in microseconds (Brogaard, 2010).
Programs running on high-speed computers analyse massive
amounts of market data, using sophisticated algorithms to exploit
trading opportunities that may open up for milliseconds or seconds.
Participants are constantly taking advantage of very small price
imbalances; by doing that at a high rate of recurrence, they are able
to generate sizeable profits. Typically, a high frequency trader would
not hold a position open for more than a few seconds. Empirical
evidence reveals that the average U.S. stock is held for 22 seconds
Updates and orders with the TWS API occur on the order of 10s to 100s of milliseconds, as far as I can tell, which would disqualify it for use in the regime described in the article.  (This is just what I have measured on my own computer on my retail Internet connection.)
Honestly I would be surprised if anyone could do HFT with any retail product.  Sounds impossible.
Comment: http://www.gndt.com/ and http://www.limebrokerage.com/ is probably as close as you can get but you'd have to do significant volume in order to get a commission structure that lets you take advantage of any short term opportunities
Comment: I worked in this area for 8 years. Most HFT algos are actually quite simplistic and typically a limited size opportunity. The key to making money is Time & Price priority. The first person to arrive normally gets the majority of the profit. This is why speed is critical.
We were beating our opponents (which we could see in the order flow) by as little as 10 microseconds. That was enough, but they always worked to improve their game and so did we. Faster computer, faster algos, faster networks. Everything was critical and no IB wouldn't cut it. For that game neither would Lime.
Comment: Most definitions would still include something on the of order 10s of milliseconds as HFT. If you can find something sufficiently novel to exploit at that frequency, it is probably at least possible with some retail product.
Comment: Any alternatives to IB in the retail world?
Comment: Or at least not impossibly expensive!
Comment: @drobertson What broker did you use? Was this using C/C++ with raw FIX?
Answer: This has nothing to do with IB in particular. The primary issue with retail data feeds is that they run over the Internet. That means dealing with a shared line and all of the latency spikes that comes with it.
Institutional traders, even when they aren't co-located, build a private network pipe to their data vendor since that's the only way to prevent network jitter (and hacking attempts). Regardless of vendor or even application domain, it is simply impossible to run a real-time mission-critical business over the Internet.
So, no, IB can't be used for HFT. And neither can anything else.
Answer: For real HFT, IB is absolutely not going to work.
The prices in IB update a max of about 7 times a second.
However, for a holding period of 5 to 10 minutes though, which is certainly not high frequency, it works fine.
Answer: Data over IB's API is not real time. You can't even match up bid, asks, and lasts with their appropriate sizes.  It's actually a 200 ms snapshot. For more reliable data go with B-PIPE, DTN or eSignal (they all have APIs) and a high speed co-located Ethernet or T1 connection to your vendor. Lots of additional coding is required.
Comment: it's 250ms, source ib help desk
Answer: Interactive Brokers does not offer execution or even a market data feed with speeds required for HFT. With HFT trading systems now competing for micro-seconds, as opposed to milliseconds 4-5 years ago - a typical retail trader connecting over the Internet is out of league, even with dedicated lines just the network round-trip time will render any HFT attempt impossible.
That having said - Interactive Brokers provides one of the best platforms for automated trading available to retail traders and small financial advisor firms.
For example there are third party tools such as this Excel spreadsheet that I started using recently, that make automated trading easy with just basic knowledge of Excel, without any special programming skills:
http://www.tradinggeeks.net/downloads/interactive-brokers-excel-trader/
Answer: IMHO, IB is one of the best retail brokers for HFT.
It is indeed perhaps the only one that retail traders can use because:
- they provide an easy to use API to trade automatically.
- commissions are very competitive. I haven't found a cheaper broker then them
- IB is owned by HFT firm; and they seem to know what they are doing!
I have not found any subtitute to them yet!!!!


How do optical anti-aliasing filters work from a frequency domain perspective?

Question: To prevent aliasing caused by the finite number of pixels on a sensor, a blurring filter is commonly used. How does that work from a frequency domain perspective? What is the transfer function of such a filter?
Answer: In Karel Fliegel, Modeling and Measurement of Image Sensor Characteristics, Radioengineering, vol. 13, no. 4, December 2004, he gives the optical transfer functions (OTFs) for different detector photosensitive area shapes. OTF is the Fourier transform of the spatial domain impulse response. The spatial domain impulse response, also called the point spread function (PSF), is a 2-d function that is constant-valued (assuming uniform sensitivity) inside the detector photosensitive area and zero outside it.
If there is an optical low-pass (blurring) filter in front of the sensor or implemented by shaking the sensor, another PSF describes it, and the total PSF is the convolution of the PSF of the sensor element and the PSF of the optical low-pass filter. The total OTF is the product of the two OTFs. Birefringenge-based optical filters (for example patent US 6937283 B1) create shifted copies of the image so their PSFs are sums of shifted and possibly scaled Dirac pulses. For example, a square arrangement of four Dirac pulses is equivalent to a cascade of a horizontal and a vertical comb filter.
An optical anti-aliasing filter also attenuates in-band frequencies that would not alias. Using a software sharpening filter the amplitudes of those frequencies can be restored. This also amplifies aliased frequencies, but because their attenuation in the combined OTF of the anti-aliasing filter and the detector is stronger, they retain some of that attenuation.
Here is an example analysis of a horizontal-vertical-separable total PSF that includes 1) a square photosensitive area, 2) a birefringent optical low-pass filter that has a PSF that consists of a square arrangement of Dirac pulses separated horizontally and vertically by 0.4284281154 times pixel width, and 3) a digital post-processing filter (operating on the pixel data), which can be separated to a cascade of a horizontal and a vertical filter, both with a PSF [-0.01536945896, 1.030738917, -0.01536945896]. A square grid of pixels with no gaps between pixels (100 % coverage of the imaging plane by photosensitive areas) is assumed. The analysis is done only along one of the separable dimensions for simplicity, but it would be better to do a 2-d analysis.
Figure 1. Red: combined one-dimensional PSF of the optical anti-aliasing filter, the square photosensitive area, and the digital sharpening filter. Turquoise: the ideal sensor PSF for a square grid (sinc function). Black: PSF of the square photosensitive area. Horizontal axis: displacement in units of one pixel width.
Figure 2. One-dimensional OTFs (Fourier transforms) of PSFs of Fig. 1, using the same color code. Horizontal axis: spatial frequency in units of radians per pixel width. There are some plotting artifacts that make parts of the red curve invisible.
Considering sinc (Fig. 1) as the ideal one-dimensional PSF, the mean square error for imaging spatial white noise is reduced by 40 % by using the optical anti-aliasing filter and the digital sharpening filter. The sum of squares error can be calculated as the integral over the square of the difference between sinc and the actual PSF, or by Parseval's theorem equivalently in the frequency domain using the differences of the OTFs (Fig. 2). I optimized the coefficients and the amount of separation in the optical anti-aliasing filter so that the mean square error is minimized.
Without the optical anti-aliasing filter, a digital post-processing filter (not a sharpening filter this time) with optimized coefficients [0.06765983302, 0.8646803339, 0.06765983302] only reduces the mean-square error by 11 % compared to a reduction of 40 % from the combination of an optical anti-aliasing filter and a post-processing sharpening filter, so it is apparent that optical anti-aliasing is useful.
Answer: An anti-aliasing filter is basically just a low pass filter.  The in images, aliasing happens when you upsample the signal (i.e. increase the number of samples used to represent the signal/image).  This results in a blocky/pixelated image because you aren't really adding more information, you're just increasing the number of pixels that a single pixel of information used to represent.  Imagine the following trivialized example:
Imagine this is the numeric representation of your data:
0,1,2,3,4,5,6
Now lets upsample by a factor of 4:
0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,6,6,6,6
What used to be a nice continuous slope is now blocks of flat, unchanging values separated by a sudden increase in value.
From a frequency perspective, these sudden increases represent very high frequency components (quick change == high frequency).  To "remove" this, we use low pass filters to smooth out these transitions.  Visually, it looks like we have more information resolution, but in reality, we just interpolated the original low resolution data.
Comment: I'm familiar with the Nyquist–Shannon sampling theorem. My question relates to an optical filter. For an optical sensor, you cannot control the sampling rate, i.e. the distance between the sensors. You need to use an optical filter to remove aliasing in the spatial dimensions. You cannot achieve this in the digital domain. The anti-aliasing filter needs to be analog. Aliasing does not only happen when you up sample(interpolate) or down sample(decimate). It occurs when you convert from the analog to the digital domain.
Answer: The optical device called optical lens works by forming an analog image of 3D real world on a flat 2D surface called the imaging plane. The most fundamental formula for the image formation of an ideal lens is:
$$ \frac{1}{f} = \frac{1}{d} + \frac{1}{s} $$ where $f$ is the focal length of the lens, $d$ is the real object distance to the lens and $s$ is the distance of the object's created image to the lens (+ on the other side wrtt object). For example when an object is at a large distance from the lens; i.e., $d \gg f$, then it tells that the image formation distance $s \approx f $ .
During the image capturing process, the image sensor is typically held at a fixed distance $s$ to the lens, except when the lens is slightly moved backward or forward for minor focusing adjustment. Therefore for an ideal lens, real world objects placed at the exact distance $d = \frac{s-f}{s f}$ becomes infinitely sharp on the image plane. Any other points which are not at this correct distance to the lens, will create blurry images due to being defocused on the image plane. And from a spatial-frequency domain perspective a blurry image means a low pass filtered image.
In order to relate this blurry (lowpass) image to an anti-aliased image we shall consider the spatial-sampling performed by the grid of sensor pixels on this 2D image plane where the distance between the consequitive pixels define the spatial sampling period. According to sampling theorem if the 2D Fourier transform of the analog image contains spatial-frequencies whose period is less than twice the pixel distance of the sensor, then there will be aliasing in the captured sampled image; i.e., the discrete-space sampled image will contain low frequency variations which does not exist in the original analog image formed by the lens on the image plane.
In order to avoid this aliasing to happen, what's required is the optical lowpass filtering of the analog image that's formed on the image plane, so that the Fourier transform of the resulting blurry image will be bandlimited to a maximum spatial frequency whose period is at least larger than twice that of the pixel distance of the sensor.
And as a matter of fact optically what realises this anti-aliasing lowpass filtering is the lens by a slight defocus of the image and also due to its imperfections (non-ideality) such as geometric aberrations and finite aperture size...
Therefore the result of this optical image formation mechanism is such that the spatial frequency content of the analog image decreases to the point where the spatial sampling is performed above the highest frequency in the image.


Can we run selenium scripts in a specific version of a browsers. i.e. Run script on chrome 52 and 53?

Question: Selenium invokes only the installed version of the browser to run its script.
how can i add this feature to my selenium framework like:
run the script on Chrome 50,52 and 53.
same with firefox, Safari and IE.
Answer: On a single computer you can only install one version of each browser. So to run your Selenium tests against multiple version you will need multiple machines.

Easiest: Setup a virtual machine, install browser version of choice (disable automatic updates), install test-runner tools, copy tests to virtual machine and run the tests.
Medium: Run you tests against online browsers services, like BrowserStack, SauceLabs or other alternatives.
Hardest: Setup a Selenium Grid and configure each virtual machine with unique version numbers. Ask the grid for capabilities so your tests runs can find the correct nodes on the grid.
Most time consuming: Removing the browsers version and reinstalling the version you want to test against.

Another issue you will have is finding the older versions, but searching for them is possible. Directing you to all older versions is to broad for this question. For the Safari on Mac you might need older version of the operating system as Safari is only shipped with OS-updates.
I would recommend using one of the online services if you really need to test and support a broad range of browser versions. Else just support the latest version and add a disclaimer that the users need to upgrade or expect possible issues.
Comment: It is possible to install more than one version of a browser on a machine. For FireFox you can use the collection form utilu: https://utilu.com/UtiluMFC/ I don't know how this works with Selnium. You can also use Browseemall, a testing tool for testing browser compatability. That tool claims good integration with Selenium.
Comment: Yes, there are some ways to have multiple browser of FF and IE, but I am not sure I would recommend them. Portable would be one option: https://portableapps.com/apps/internet/google_chrome_portable but it is not the same, possible you could have other problems or things that work slightly different as these browsers are repackages. As a tester I would like to mimic the real experience as much as possible. Never the less please add another answer if you have better ideas :)


If a Mormon man turns from Mormonism, what happens to his Mormon wife when she dies?

Question: I'm told that according to Mormon doctrine, a Mormon woman has to be granted entry into heaven by her Mormon husband. Assuming my impression is correct, what would happen if the husband turned from Mormonism and then died? Would the wife need to quickly remarry a Mormon before she died in order to get to heaven?
Comment: @Waeshael: What site are you referring to?  The only places I've seen on official LDS sites that require you to be logged in with a Church membership identification involve membership records or other "personal profile" level information, (the sort of thing any site would want to protect behind a login,) not doctrine.
Comment: Somewhat related: [What does the LDS Church teach about marriage in the afterlife?](http://christianity.stackexchange.com/questions/4677/what-does-the-lds-church-mormon-teach-about-marriage-and-polygamy-in-the-after?rq=1)
Comment: I really think that for answers on LDS doctrine we must go to the official LDS theology site. This requires that the answerer has a membership ID, otherwise you will get quotations from material written for "gentiles."
Comment: It's a bit like the NT. You can read about the activity of Jesus, but the description of his training methods (how to baptize, raise the dead, heal lepers, make the blind see, the lame walk etc.) was not released to the public, but was retained by the Bishops in church archives. Unless you were a Priest in those days, you wouldn't be told what to do.
Comment: Regarding the LDS web site after login. It forbids copying any of the data to another site. It allows only personal use of the material.
Comment: I wonder what would happen to the female unmarried Mormons.
Comment: Waeshael is wrong about the LDS.org site. All the manuals are public. Mason Wheeler is correct about the material that is behind the login.
Comment: I'm guessing Waeshael is referring to Handbook 1 or Letters.LDS.org, which are focused on Church polices and procedures more than an exposition of doctrine and theology.
Answer: Perhaps some things should be clarified a bit here first.
First part of your question:

I'm told that according to Mormon doctrine, a Mormon woman has to be granted entry into heaven by her Mormon husband. Assuming my impression is correct, ...

Not really.
Unmarried women can certainly get to heaven -- and depending on what you mean by "heaven," they don't even have to be Mormon. Remember, Mormons believe what Paul teaches about the three degrees of glory in 1 Corinthians more literally than most Christians, in that there are three main kingdoms, all of which are called "heaven."
Unmarried men and women can even obtain the highest kingdom. However, in the Doctrine and Covenants, section 131, more is revealed about this state (the celestial glory):

1 In the celestial glory there are three heavens or degrees;
2 And in order to obtain the highest, a man must enter into this order of the priesthood [meaning the new and everlasting covenant of marriage];
3 And if he does not, he cannot obtain it.
4 He may enter into the other, but that is the end of his kingdom; he cannot have an increase.

To obtain this highest glory is called exaltation. It is living like God does, being as He is.
Eternal marriage (also called a sealing), faithfully kept by both individuals, happens to be that final requirement.
I suppose then, that what you mean by "going to heaven" is actually exaltation.
So, on to the next part of your question:

... what would happen if the husband turned from Mormonism and then died?

He would face the consequences in the hereafter on his own. It's not even so much about turning from "Mormonism" at that point, but rather about breaking your covenants made in the temple, to God and to your wife, for which he would need to repent.

Would the wife need to quickly remarry a Mormon before she died in order to get to heaven?

No. Again, assuming you mean, "in order to obtain exaltation": LDS members are taught and reminded (a few sources below) that all who are faithful here will have everything and more made up after this life, and all who do not have the opportunity to be eternally married here will be able to be sealed to a faithful husband there, if that be their desire.
The eternal nature of covenants performed in the LDS temples means that whether they are made in this life or the next, they are in effect for eternity (cf. parable of the laborers in the vineyard).
Sources and further reading:

Gospel Principles, Chapter 38: Eternal Marriage "all Heavenly Father's children who are faithful to their covenants in this life will have the opportunity to receive all the blessings of the gospel in the eternities, including the opportunity to have an eternal family."

The Eternal Blessings of Marriage (a recent General Conference address) "All things are possible to the Lord, and He keeps the promises He inspires His prophets to declare. Eternity is a long time. Have faith in those promises and live to be worthy of them so that in His time the Lord can make them come true in your life. With certainty, you will receive every promised blessing for which you are worthy."

To the Single Adult Sisters of the Church "I also recognize that not all women in the Church will have an opportunity for marriage and motherhood in mortality. But if those of you in this situation are worthy and endure faithfully, you can be assured of all blessings from a kind and loving Heavenly Father—and I emphasize all blessings. I assure you that if you have to wait even until the next life to be blessed with a choice companion, God will surely compensate you. Time is numbered only to man. God has your eternal perspective in mind."
Comment: This is a good answer, but I want to add one clarification. During a temple marriage (a sealing) the husband and wife each make a commitment to God to honor the marriage, rather than to each other. If one person in the marriage decides to leave the faith, that does not automatically cancel the sealing covenant. The belief is that if the other spouse remains true to the covenant, it will be honored by God in His own way. Many people find their temple promises strengthen their marriage even when one spouse leaves the faith.
Answer: Simple answer: Every worthy person will inherit all blessings they qualify for, regardless of any other person (parent, spouse, children, ancestor, etc.) The seeming confusion may come from the statement that the highest level of heaven is for married couples, which means that neither a man nor a woman can live there without the other. But, a person dying without being married is not hopeless, because there is the age of the Millennium in which a person could also get married. After that, God will have ways to bless anyone who desires to be married, and not keep her/him from that blessing. Otherwise the system would be incomplete, and it's not (even if we can't see it all).


Setting up FTP for specific folders

Question: I want users to be able to upload files via FTP to my site (IIS 7.5). Once the file is uploaded, then I want to process the file. Is there some guide that steps through how to setup FTP to point to a specific location where I want the files to be dropped?  Can I setup FTP to point to a different subfolder based on the user that logs in?
Answer: You're probably looking to set up FTP user isolation. Here's a guide:
http://learn.iis.net/page.aspx/305/configuring-ftp-user-isolation-in-iis-7

Setting up FTP for specific folders


Transforming shredded cheese into chunk cheese

Question: I am at an event where I need to serve cubed chunk cheese, but I only have shredded mozzarella.  Is there a simple way to melt mozzarella into chunks?  Any idea would help.
Comment: I've never tried it, but I'd be inclined to warm it up 'til it's soft (possibly in salted hot water, like when shaping it originally), work out the air, let it solidify in a slab, then cut it up.
Answer: Normally when you have smaller cheeses you use a cheese press to mash them together. Make 1 round of cheese. Only thing I could think of would be to see Felx. Our local blacsmith & have one made. As a specialty item. Kind of like a long handled garlic press with out the holes in it. Think along those lines. Something cube shaped you can mash the cheese together in.
Comment: In a similar vein to the garlic press-like thing, you might also be able to put it a disk in the bottom of a ricer and make a wheel (then cut it into cubes)
Answer: There is no way, neither simple nor difficult. You can only create a block of cheese during production. Once you shred it, there is no way back.
You can in principle make processed cheese which is meltable and shapeable to a point, but it doesn't have the mouthfeel and taste of chunk cheese either. You have probably eaten it as these edges packed in foil which can be sperad on bread, for example from La vache qui rit.
Answer: Found a good solution: simply shape the mozzarella into smooth balls.  No melting even necessary!  At this point, I could have chopped them into cubes, but I left them as spheres.
Comment: Did you have to heat it?  I know that you typically put the mozzarella curds into hot water to soften up so that you can make it into balls.
Comment: Nope, didn't even need to heat them; just molded them like dough.


What are the symptoms of Migraine and how to categorise into severe or mild etc

Question: How to identify if someone suffers from migraine? and how is the migraine categorised ie whether it is severe, mild etc?
Comment: This should really be two questions.  Entire chapters could be written for each of the two questions.
Comment: Are you asking 1. What are the symptoms?, 2. how is the migraine categorised?, 3. how to identify someone who suffers from migraine?,  I've answered your questions 1. & 2., but it got removed for non-answering your questions I guess. See [meta](http://meta.health.stackexchange.com/q/253/114). Can you comment or clarify what you're asking or does my answer address your question correctly?
Answer: How to identify migraine
Traditionally, if you had headaches you would discuss your symptoms with a doctor who would then classify the type of headache you had based on what you reported. If you didn't think of something to report, or didn't think (for example) that your nausea was related to your headaches (and so didn't report it), then your headache type may be misdiagnosed. Personally, I received several different "headache diagnoses" over the years, depending on how I reported my symptoms and the doctor I was seeing at the time.
In 2003, a group of researchers published a study (Lipton) where they determined the ID Migraine test was a reliable screening test for determining whether a patient had migraine. This test was further validated by additional studies in 2011 (Cousins), and has since been translated into additional languages and studied further (Karli).
ID Migraine Test
The ID Migraine test is considered positive for migraine if the patient answers yes to 2 or more of the following 3 questions:

Has a headache limited your activities for a day or more in the last three months?
Are you nauseated or sick to your stomach when you have a headache?
Does light bother you when you have a headache?

Migraine Symptoms
More generally, the symptoms of migraine may include:

Pain on one side or both sides of your head
Pain that has a pulsating, throbbing quality
Sensitivity to light, sounds and sometimes smells
Nausea and vomiting
Blurred vision
Lightheadedness, sometimes followed by fainting
Aura

Visual phenomena, such as seeing various shapes, bright spots or flashes of light
Vision loss
Pins and needles sensations in an arm or leg
Speech or language problems (aphasia)

How to classify severity of migraine
Severity of migraine is usually judged based on how the symptoms affect the patient's ability to conduct daily activities. There are several scales available to test this, but the two most popular seem to be the Migraine Disability Assessment (MIDAS) and the Headache Impact Test (HIT).
MIDAS
MIDAS was developed in 2001 (Steward) and is based on asking the patient to count the number of days they have been impacted by their headaches (specifically addressing work, household, and social activities). The more days a person is impacted, the more severe their migraine is considered.  MIDAS can be found online at the American Headache Society.
HIT
HIT is a newer test, developed in 2011 (Yang). It asks the patient to consider the impact of migraine on their activities in the past 4 weeks, on a five point scale that progresses from "Never" to "Always". Having more responses on the positive end of the scale (Sometimes/Very Often/Always) will indicate that a person is more severely affected by migraine. The HIT can be found online on the National Headaches Foundation.
References
Cousins G1, Hijazze S, Van de Laar FA, Fahey T. Diagnostic accuracy of the ID Migraine: a systematic review and meta-analysis.
Headache. 2011 Jul-Aug;51(7):1140-8. doi: 10.1111/j.1526-4610.2011.01916.x. Epub 2011 Jun 7.
Karli, N, Mustafa Ertas, Betül Baykan, Ozlem Uzunkaya, Sabahattin Saip, Mehmet Zarifoglu, Aksel Siva, and MIRA study group. The validation of ID migraine™ screener in neurology outpatient clinics in Turkey. J Headache Pain. 2007 Sep; 8(4): 217–223. Published online 2007 Sep 24. doi:  10.1007/s10194-007-0397-4
Lipton RB, Dodick D, Sadovsky R, Kolodner K, Endicott J, Hettiarachchi J, Harrison W; A self-administered screener for migraine in primary care: The ID Migraine validation study. Neurology. 2003 Aug 12;61(3):375-82.
Stewart WF, Lipton RB, Dowson AJ, Sawyer J. Development and testing of the Migraine Disability Assessment (MIDAS) Questionnaire to assess headache-related disability. Neurology. 2001;56(6 Suppl 1):S20-8.
Yang M, Rendas-Baum R, Varon SF, Kosinski M. Validation of the Headache Impact Test (HIT-6TM) across episodic and chronic migraine. Cephalalgia. 2011;31(3):357-367. doi:10.1177/0333102410379890.
A prospective study on osmophobia in migraine versus tension-type headache in a large series of attacks
Terrin A, Mainardi F, Lisotto C, Mampreso E, Fuccaro M, Maggioni F, Zanchin G. A prospective study on osmophobia in migraine versus tension-type headache in a large series of attacksCephalalgia. 2019 https://doi.org/10.1177/0333102419877661
Answer: The migraine is a chronic neurological disease. Its main symptom is usually an intense headache that occurs at the front or on one side of the head and the pain could gets worse when you move and prevents you from carrying out normal activities.
The symptoms of a migraine can usually last for few hours or few days. Other common symptoms could include: nausea, vomiting and increased sensitivity to light and sound, however not everyone experiences these additional symptoms. Some other could include sweating, poor concentration, feeling very hot or very cold, abdominal (tummy) pain and diarrhoea. Migraine headaches are often undiagnosed and untreated.
There are several types of migraine how it's categorised, such asNHS:

migraine with aura,
This is when there are warning sings before migraine starts (such as flashing lights).
migraine without aura,
Where migraine occurs without warning sings.
migraine aura without headache.
Where other symptoms are experienced (such as aura), but without headache.

And the main stages of a migraine (although not everyone goes through all of these) areNHS:

'Prodromal' (pre-headache) stage
This early symptom can indicate the start of a disease. For example changes in mood, energy levels, behaviour and appetite can occur several hours or days before an attack.
Aura
Retinal migraine (visual migraine) can be accompanied by visual disturbances such as flashes of light or blind spots, which can last for five minutes to an hour or even temporary blindness in one eye.
It vary by individual experience (smells, lights, or hallucinations).
Headache stage
Throbbing or pulsatile pain on one side or both sides of the head lasting for few hours to 72 hours. Often accompanied by nausea, vomiting, and/or extreme sensitivity to bright light and loud sounds.
Postdrome (Resolution stage)
When symptoms gradually fade away, you may till feel tired for a few days afterwards. During this time you may feel drained and washed out, some other people report feeling mildly euphoric.

See also:

What are the general causes of migraine and how can it be treated?
Tension headache at Wikipedia
Migraine Symptoms by Mayo Clinic Staff


If a software project has a permissive open source license is it plagarism to copy text to a paper without attribution?

Question: Many open source software projects have licenses that allow freely copying source code and using it however you want. Some of these licenses do not even require attribution. Source code is just text so my question is is it legal to copy text from for example a README and include it in a paper without attribution, supposing I'd want to do that for some reason?
Comment: Why don't you want to include attribution? Attribution in this case makes it much easier to see where the text comes from, thus to judge any claims made either in it or related to it. If neither of those are relevant, then what purpose does the text serve in the paper in the first place?
Comment: To be honest I only asked this because I was curious. I enjoy asking the what if questions. In programming copying code with a permissive license not requiring attribution does happen. So I was wondering how this extended to writing.
Answer: It is plagiarism to claim someone else's writing as your own in any context.  Note that while plagiarism can be a legal term - that is, some forms of plagiarism are illegal - actions that are legal can still be considered plagiarism.  For one example, many higher learning institutions have rules that forbid you from plagiarizing yourself by reusing parts or all of one work in multiple classes. (Google 'self plagiarism' for more details.)
The question of whether an act is plagiarism and whether an action is legally actionable are distinct questions.  The question of whether or not including a README or other text from a licensed work could get you into legal trouble is unanswerable without details of the license, etc.  But if you claim or appear to claim that you wrote it when you did not, it is plagiarism.
Answer: There is no single response. It really depends on the license of the project from which you want to quote the source. There is 83 OSI approved licenses and many unlisted in the wild that can match your needs. Each license has its own requirements, its "little lines to read carefully". Attribution may or may not be a requirement.
Can those licenses applied to some literature work? I think so. Some, like the GNU Free Documentation License was written specially to deal with... documentations, which are somewhat literature. Deeper, many agreed that source codes are words, so the licenses apply to those words.
So, if

Code is Poetry (WordPress)

let's be tautologic : if attribution is required, it is required.


Bandwidth and block size for Paillier cryptosystem

Question: Can someone clarify what is meant by the terms cryptosystem bandwidth and block size for public key cryptosystems;
The context is the Paillier cryptosystem and its Damgård-Jurik generalisation. My intuition is that they refer to the modulus. Since the modulus is $n^2$ and $n^s$ respectively does it apply that they have more bandwidth/block size than ElGamal which computes $mod \;\; q$;
Is this intuition correct;
Comment: Bandwith is normally related to time. So without some kind of performance metric, it would be tricky to say something about it. With asymmetric crypto-systems you do have *overhead* because the size of the ciphertext produced is normally larger than the plaintext. Also note that asymmetric cryptosystems almost always are paired with a symmetric hash or encryption algorithm, making the overhead less of an issue.
Answer: Let $c$ denote a ciphertext and let $m$ denote a plaintext.
To my best knowledge, researchers in cryptography employ "bandwidth" as different meanings, say, ciphertext expansion ($|c|/|m|$) or a number of bits of plaintexts contained in a ciphertext ($|m|$). @owlstead refers "overhead," which is $|c| - |m|$.
For example,

Joye and Libert (EUROCRYPT 2013, ePrint 2013/435) wrote that "the scheme is computationally efficient but somewhat wasteful in bandwidth as $k \cdot \log_2{N}$ bits are needed to encrypt a $k$-bit message." Here, the scheme is the Goldwasser-Micali scheme and it encrypts a bit into a ciphertext of length $\log_2{N}$ and "bandwidth" seems to be $|c|/|m|$.
Chevallier-Mames, Naccache, and Stern (SCN 2008, ePrint 2008/119) defined "bandwidth" as the number of bits contained in a ciphertext, that is, $|m|$.

I think you mean the latter, i.e., $|m|$ and "block size" seems to be $|c|$.
Let us calculate $|m|/|c|$.

Paillier: The plaintext space is $\mathbb{Z}_n$ and the ciphertext space is $\mathbb{Z}_{n^2}$. Hence, the ratio of bandwidth/blocksize is $1/2$.
DJ with $s\geq 1$: The plaintext space is $\mathbb{Z}_{n^{s}}$ and the ciphertext space is $\mathbb{Z}_{n^{s+1}}$. Hence, the ratio is $s/(s+1)$.
ElGamal: The plaintext space is $\mathbb{G}$ and the ciphertext space is $\mathbb{G}^2$. Hence the ratio is $1/2$.
Comment: Hi curious. The ciphertext *length* is log n^2 and that of plaintext is log n. Hence we got 1/2.


Is animation cancelling worth learning if you don't main AD carries?

Question: It's a game mechanic that takes many hours of practice to perfect, but is it worth it to learn if you're hardly using the AD carries in LoL?
Answer: Sort of a tangent, but if you plan to successfully climb the solo queue ladder, you will have to play AD carries.  Not to mention that understanding the aspects of all lanes is essential regardless of which role you fill.
Animation cancelling is more prevalent in other games such as StarCraft:BW and DOTA, but it is still useful in LoL.  Basically it will reduce predictability in lane when you're last hitting as a ranged champion (generally mid and bot) as you're standing still for a fraction of the original animation time.
Personally, I come from a SC:BW background and animation cancelling is second nature so I didn't have to spend time practicing it, however all it takes is realizing how long the attack animation for each champion lasts.  Once you attempt to cancel it and fail a few times (by cancelling the entire AA and consequently its damage), you'll pick it up quickly.
Comment: I don't know, I find that by staying quiet in champion select you almost never end up with ADC... It's one of the most popular roles. Learning to play support well, on the other hand....
Answer: I use it in any farming lane, not the jungle. I'd say its nice to know how to do if you want, otherwise dont worry about it.
Comment: Care to explain why the difference matters?
Answer: Animation cancelling shows huge mechanical control. Learning it may improve your game in other ways. It is always good to learn new things.
No it is not required but is a good way to gain more control over all characters


Impulse Sweep and Phase

Question: can some one tell me how the sweep profiles the phase of each frequency, and how this is reflected on the impulse sweep...I can see that when the sweep moves across the spectrum to profile a systems physical properties it modulates in amplitude and pans left and right but how about the phase, how can we observe the phase effect on the sweep...
Answer: The phase characteristic of a sweep signal is linear, starting from 0 and increasing over time up to 2*Pi.
For a very clear explanation of this, I suggest you see the paper Transfer-Function Measurement with Sweeps from Swen Müller and Paulo Massarani.
If you use a sweep signal to measure an impulse response, the phase curve will have to be compared to this linear curve to understand the time delays (phase shifts) introduced at each frequency.
Comment: measuring the phase offsets/fluctuations is where I am having difficulty with, simply put what kind of audio manipulation to the sweep introduces these phase offsets at different frequencies...is there a matlab code to plot the phase offsets introduced by the impulse being profiled with the sweep, or some kind of phase meter that is on phase to frequency mode, to observe the phase shifts at different frequencies while processing the sweep, simple pitching up and down the sweep at different frequencies of the sweep, will that introduce phase offsets to our impulse when the sweep is deconvolved?
Comment: JimiJazz, by the way thanks  for that in depth scientific article...very informative data.
Comment: I found this tool to measure and display the phase to frequency of the sweep once it is deconvolved  into an impulse...[Christian/Applications/Measurement/VSTPluginAnalyser](http://www.savioursofsoul.de/Christian/Applications/Measurement/VSTPluginAnalyser.7z)
Comment: @texture if you're still interested in Matlab code to watch the effects I would try the ITA Toolbox, and would then subtract the phase response of your system to the phase response of the sweep.
Comment: thanks JimiJazz, that was very helpful! those tools are awsome and well coded.
Comment: @texture If this answers your question, can you please mark it as answered?

Impulse Sweep and Phase


Why do some US States have a different age of consent for each gender?

Question: Utah and 8 other US States have different ages of consent for each gender. Why is this?
Comment: Women can get pregnant, so men can be held to stricter conditions --   https://supreme.justia.com/cases/federal/us/450/464/#468 - the Equal Protection Clause *does not* "demand that a statute necessarily apply equally to all persons" or **require "things which are different in fact . . . to be treated in law as though they were the same,"** Rinaldi v. Yeager, 384 U. S. 305, 384 U. S. 309, a statute will be upheld where the gender classification is not invidious, but rather realistically reflects the fact that the sexes are not similarly situated in certain circumstances. Pp. 450 U. S. 468-469.
Comment: I'm voting to close this question because questions relative to *why* such and such laws exist are for the Politics stack exchange. Having passing comments about the rationale of laws is fine, but if your question isn't about what the consent ages are in different jurisdictions, I don't think it belongs in LawSE.
Answer: Women can get pregnant, so men can be held to stricter rules:
From https://en.wikipedia.org/wiki/Ages_of_consent_in_the_United_States

Although legislation tends to reflect general societal attitudes
  regarding male versus female ages of consent, Richard Posner notes in
  his Guide to America's Sex Laws:
The U.S. Supreme Court has held that stricter rules for males do not
  violate the equal protection clause of the Constitution, on the theory
  that men lack the disincentives (associated with pregnancy) that women
  have, to engage in sexual activity, and the law may thus provide men
  with those disincentives in the form of criminal sanctions.
Posner, Richard (1996). A Guide to America's Sex Laws. The University
  of Chicago Press. p. 45. ISBN 0-226-67564-5. The case cited is Michael
  M. v. Superior Court, 450 U.S. 464 (1981).

However, to modern sensibilities, this doesn't justify the states that have age of consent lower for women. [The pregnancy argument would mean states could punish an adult male for sex with a minor female, to protect the woman. Whereas a minor male of that same age doesn't necessarily need the same protection, at least for that concern.]
Law in those states seems to be an attempt to mirror the historical tendency for men to be slightly older than women when marry - but re goal of discouraging sexual predation, those states have it backwards.
I'd have to agree with the answers that speculate this is a patriarchal holdover that eventually will change or be overturned. [But US Supreme Court - having ruled it isn't inherently an Equal Protection violation - seems inclined to leave these laws alone regardless of which age is slightly lower; leaving it to the states to decide the non-symmetric circumstances of the sexes.]

More detail from the case itself:

(a) Gender-based classifications are not "inherently suspect" so as to
  be subject to so-called "strict scrutiny," but will be upheld if they
  bear a "fair and substantial relationship" to legitimate state ends.
  Reed v. Reed, 404 U. S. 71. Because the Equal Protection Clause does
  not "demand that a statute necessarily apply equally to all persons"
  or require "things which are different in fact . . . to be treated in
  law as though they were the same," Rinaldi v. Yeager, 384 U. S. 305,
  384 U. S. 309, a statute will be upheld where the gender
  classification is not invidious, but rather realistically reflects the
  fact that the sexes are not similarly situated in certain
  circumstances. Pp. 450 U. S. 468-469.
Comment: There is also a historical view, based in psychology, and substantiated well enough to support a legislatively determination that an distinction is appropriate, that women mature sooner than men and are less impulsive.
Comment: While a good point, this overlooks the blatant motivation to allow men to marry women at a younger age, before they have established themselves as independent adults. The reason this is problematic in practice, is the high correlation with social pressures in those societies, such that its likely to be coercive, abusive. These are laws passed by men, in the interests of men. Not being done for the interests of the women. If you doubt this, study the states that have these laws. Nevertheless, that is up to each state to sort out.
Comment: The dead giveaway as to what is going on, is to compare the ages of the man and the woman. If the man is 19, and the woman is 16, then this fits biological desires of both genders, such that the man is often more established, thus older. Beyond that three year difference, its healthier to wait. The legislation wasn't passed by 18 and 19 years olds wishing they could marry a 16 year old...
Answer: This is more a question about society and politics than about the law; that is, you know what the law is you want to know why.
Without any research and no idea of the particulars I can say that the reason is historical and derives from the fact that our society has been (and still is) a patriarchy and has deeply ingrained sexism (along with a lot of other -isms). These laws were laid down when it was considered not only acceptable but prudent and reasonable to treat men and women differently and nobody has got around to changing them.
That said, they are quite likely unconstitutional as discrimination on the basis of sex is unlawful. For why they are still there see Why do municipalities keep laws on the books that are invalid? - it is equally applicable to states; I would suggest my idea No 1.
Comment: The biological consequences of sexual relations are rather different for males and females, especially in the event that one of the participants skedaddles afterward; the disparity of consequences would seem a reasonable basis for disparate treatment under law.
Comment: @supercat, your argument would make perfect sense for making age of consent higher for females than males; however, in Utah, it's actually the reverse!
Comment: @cnst: I don't know the history of Utah's laws, but they could be justified on the basis that for a girl to become pregnant represents at most a nine-month commitment after which she may place the child adoption, while a boy getting a girl pregnant represents an 18-year commitment if the girl wants the baby.  On the other hand, in today's legal climate it's not even always necessary for a male to actually get a female pregnant to be hit up for child support.  From what I've read in some states a male who fails to challenge a judicial finding of paternity within a certain time frame...
Comment: ...can sometimes be prohibited from challenging it later even if DNA proves he's not the father, and even if he was not made aware of the original finding within the timeframe when he was supposed to have challenged it.  So I suppose by the aformentioned logic the age of consent should apply not only to sex, but also to anything a boy might do that might make a girl think that she should name that boy as the father of any baby she might have.
Comment: @supercat Are these really comments on the answer? Or would you better off writing your own answer?
Comment: Conventional wisdom upon which legislatures have acting in part and which has some empirical support is that women mature intellectually at a younger age than men.
Answer: The Equal Protection clause of the 14th amendment provides for equal protection under the laws.
The Supreme Court has held this prohibits sex based discrimination, unless the government proves this law satisfies the intermediate scrutiny test.
In brief, this test means: the law furthers an important government interest in a way that is substantially related to that interest.
This standard was applied in Craig v. Boren (1976). In this case: "Oklahoma passed a statute prohibiting the sale of 'nonintoxicating' 3.2% beer to males under the age of 21 but allowed females over the age of 18 to purchase it. The statute was challenged as Fourteenth Amendment Equal Protection violation by Curtis Craig, a male who was over 18 but under 21, and by an Oklahoma vendor of alcohol."
In this case the Supreme Court "held that the gender classifications made by the Oklahoma statute were unconstitutional because the statistics relied on by the state were insufficient to show a substantial relationship between the statute and the benefits intended to stem from it."
For more see: https://en.wikipedia.org/wiki/Craig_v._Boren
In this day and age, it is unlikely that different age of consent laws would be upheld. The only problem is that you must have standing to challenge such laws. As minors cannot file lawsuits, without their parents, the most likely case providing standing would be where someone knowingly violates the law and is arrested for violating it. Then the person would have legal standing to challenge the age of consent laws. But that requires a lot of effort, could result in you spending some time in jail while the case is appealed and so forth.
Even more likely, the differences in age of consent will not be enforced by the government, leading a situation, where the law is on the books, and has not been ruled invalid, yet is most likely unconstitutional.
TL;DR: So in the end, the ages are practically not different, and just historically exist on the books as different.
Edit: as pointed out by ToolmakerSteve, (Thanks!) there actually is caselaw on this issue: Michael M. v. Superior Court, 450 U.S. 464 (1981). It was a plurality opinion and it seems to be quite a persuasive authority on this issue. In the current composition of the Supreme Court staggered age of consent laws by gender would probably continue to be upheld; when I first wrote this answer Justice Kennedy was still a Supreme Court justice and his expansive view of the equal protection clause seemed to swing such a case the other way.
Comment: I would more agree with supercat's reasoning that the consequences of having sex can be quite different for men and women. Unlike the alcohol case.
Comment: @gnasher729 the government still has to meet intermediate scrutiny in this case. The only case law that is remotely related to the question suggests that the laws should be overturned.
Comment: The question isn't "would this law be upheld", but "why does" (or did) "the law say this"?
Comment: @david I know. But I thought it was an interesting enough point that I made an answer about it.
Comment: Viktor - "The only case law ..." No, there is US Supreme Court case law specific to this topic; see my anwser.
Comment: @ToolmakerSteve thanks for pointing it out!


Is my New York driver permit count as an acceptable id to fly in U.S.?

Question: I'm just became U.S. citizen, and I want to fly to Florida from New York next week but I don't have my U.S. passport (or U.S. passport card) yet. Can I use my driver permit to get on a plane? Some of my friends told me that the driver permit is longer acceptable to fly in U.S.. Should I bring my old passport from other country, or some other types of id, such as my student id?
Comment: In the USA, a _permit_ is usually temporary for learners and a _license_ if what you get after you have had a permit and pass the examination. A NY drivers _license_ is still acceptable. Some states' licenses do not meet standards whose enforcement has been postponed to January 2018, at the earliest. Your old passport, if not expired, will also work.
Comment: I am a dual citizen of the US and another country. I often use my foreign passport to identify myself to TSA.  If I'm not using that, I use my NY driver'slicense (most recently three days ago).
Answer: If by driver permit you mean your New York Drivers License, then yes that is an acceptable ID.  TSA is not starting to enforce the RealID rules until January 2018.
Answer: The TSA identification guidelines include the following:

Driver's licenses or other state photo identity cards issued by Department of Motor Vehicles (or equivalent)

All valid New York DMV-isssued photo documents should qualify, including

driver license
learner permit
non-driver ID
the "enhanced" versions of the above

Your friends may be referring to the REAL ID act, which imposes a federal standard for state-issued IDs. Even though the original law was passed in 2005, however, most states are not yet in compliance, as constitutionally the federal government cannot force states to adopt the standard. Therefore, most states have received extensions.
New York's extension expires October 2017 at this writing, but they are almost certainly going to receive an additional one. In the unlikely chance they do not, you can still use any of the other forms of ID listed on the TSA page, including your foreign passport if it is still valid.


What to Do with Six Pack Boxes

Question: I collected a lot of six pack boxes to put bottles of homebrew in.  Now, I've got a better container.  Since I can't recycle six pack boxes, is there anything I could do with them other than throw them out?
Comment: I don't think that's waxy coating.  Waxy coating would be like the boxes cucumbers come in at the grocery store.  They're corrugated cardboard literally coated in wax.
Comment: Out of curiosity (and I seem to be rough on 6pack carriers) what is your "better container" for bottles?
Comment: Has whoever does your recycling stated that they don't accept 6-pack boxes? Where I live, it's just treated as straight cardboard and they'll take it.
Comment: @fire.eagle: Their FAQ said no cardboard with waxy coating.  I'm assuming the glossy finish on most of the six packs qualify as "waxy coating".
Answer: Since recycling won't take them, you might try talking to the store you bought the 6-packs from originally. Every liquor store I have been in has a "build your own 6-pack" option from their singles, and they have a basket of those boxes sitting out for people to use for their selection. They might be willing to take them back to reuse for that.
I will note that I have never tried this before, but it seems reasonable that they would take at least a few.
Answer: Next time you're at your local brew shop see if they'll take em off your hands. They might leave them as a freebie for anyone who wants to take em.
The brew shop I go to sometimes has used equipment left by brewers for cheap or free.
MoreBeer sells blank 6 pack carriers for $0.95, so there's probably a homebrewer who'd pick em up.
http://morebeer.com/view_product/15640/102304/6_Pack_Carrier
Answer: If you know anyone that likes to wash and/or detail their car(s), they could use the six-pack boxes to store their car-care products. It would be worth asking them if they would like to use your six-pack boxes for storing the bottles of products.
One example of how i use them: I store the products that deal with interior in one six-pack box labeled "Interior," the products for dealing with wheels and tires in one labeled "Wheels," etc.
Comment: Good idea.  I think I'll use some of them to store my cycling stuff.
Answer: Those are not wax coated. And you can recycle them. Does your recycling center accept cardboard boxes from children's toys? Do they accept magazines? Do they accept old posters? All pretty much the same thing. You'll know wax cardboard when you see it. It does not get as easily damaged by moisture as regular cardboard. And you usually have to seek it out.
Answer: I'm thinking of covering a wall in my brewery (aka the garage) with various six-pack boxes -- probably just the side, cut out.  I have a lot of six-packs as well, but my recycling company takes them, so they'll take the cuttings or any that I don't want.

What to Do with Six Pack Boxes


distance between two circle's centres

Question: Two circles of equal radius intersect at points C and D.The centres of the two circles are points A and B respectively.If their radius is 10 units,the area of triangle ABC is 40,then how do we find the distance between A and B?
Answer: Draw a figure.
You have to find the length of the third side of an isosceles triangle with two sides length = 10 and area= 40.
This is equivalent to finding the length of twice one of the short sides of a right angled triangle with hypotenuse 10 and area 20.
So there are two solutions.
Introduce notation.
If $p, q$ are the lengths of the short sides in the right-angled triangle (so you are looking for AB = $2p$ or $2q$) then you have to solve
$$ p^2 + q^2 = 10^2, \mbox{ (Pythagoras)}$$
$$ \frac{pq}{2} = 20. \mbox{ (area triangle)}$$
If you solve this quadratic equation you get e.g.
$$p = \sqrt{80} \mbox{ or } p = \sqrt{20},$$
$$q = \frac{20}{p}.$$
Edit: corrected formula for area of triangle and solution for $p$.

distance between two circle's centres


Mounting previous windows partition

Question: I have installed windows 10 in my laptop in C Drive. I have 3 more partitions (D, E and F). If i format C drive and install ubuntu will I be able to mount the previous windows partitions (d, e and f).
If i can do , then how to do please guide.
Answer: I don't think why you won't be able to.
I have dualbooted Windows 8 with Xubuntu and Windows partions works fine on Xubuntu. I haven't tried what you asked but it
*Other partions should work even on Ubuntu.
P.S.: I am not responsible for any loss of your data. Do wait for other answers.
Comment: i dont want to dual boot. I just want to format windows and use ubuntu. will i be able to use the other drives working with windows
Comment: I would recommend to first take backup of all needed files in *C:* like files in *Documents* and *Downloads* folder.
Comment: can i mount or not? how to do?
Answer: I've done the same one year ago using Ubuntu 16.04 and It worked fine. Here, you can find how to mount the partitions.
Note: If you can back up the partitions and format them using ext4 file system, then you can have better Linux compatibility. For example, you can mount a partition as Home directory etc.
Answer: There are some things you will be able to do only in Windows, at least very easily as compared to Ubuntu. It seems to me that you're a beginner in using Ubuntu, so I would recommend not to format C drive and keep your Windows 10.
As for the partitions, you just have to click on the partition you want to mount in the Ubuntu file manager Nautilus and you're done. You can access those partitions straightaway. If not, there are two solutions I know.

Try this command in terminal:
sudo ntfsfix /dev/sda*

Replace '*' with the number of the partition. Install GParted to the know the partitions you want to mount with this command:
sudo apt-get install gparted

Or find GParted in Ubuntu Software Center.
If this does not work, go to your Windows 10 and turn off Fast Startup. Control Panel> System and Security> Change what power buttons do (Under Battery icon sub-menu)> Turn off the Fast Startup.

The partitions in Windows 10 are NTFS type and for Linux we use Ext4 file system. Windows does not support Ext4 file system but Ubuntu will support NTFS file system. Hope this helps!
Answer: I am assuming the other partitions(D,E,F) are all NTFS partitions.If so,then to mount all these partitions,you can use the Disks Utility(Search for disks) in Ubuntu in order to mount these partitions for the current session or mount them everytime you log in to Ubuntu.
Answer: Yes, certainly. Follow me:

Install Ubuntu from Live DVD/USB
While selecting disks, don't select the entire disk but, select 'Something Else'
Now at Disk Partition Manager, find the former C: drive and select it with mount as '/'
Also 'check' the 'format checkbox', format as Ext4
Go to every other partitions and select 'Do Not use this Partition' from the drop down list
If you want, you may create a Swap partition in the main C: drive
Install normally
Reboot to Ubuntu
You'll see the D:,E: and all other drives at the Unity Sidebar. Left Click them to access with the File manager.

You're with your new Ubuntu installation now!
Thanks :)

Mounting previous windows partition


When does the Deadzone movie take place in the DBZ storyline?

Question: During the story arc with Raditz they make it out as though it's the first time Piccolo and Goku team up.  With Goku dying in the Raditz fight and not showing up again until Vegeta, it couldn't have happened after that fight.  Where does it fit into the storyline before the Raditz fight?
Answer: This Wiki explains it pretty well:

Dead Zone is the only film that takes place after the end of Dragon Ball and before the beginning of Dragon Ball Z. The events of this movie can be placed into the series timeline between episodes "The End, The Beginning" of the Piccolo Jr. Saga and "The New Threat" of the Vegeta Saga.
Comment: @MCeley Exactly. Apparently, it's not in-the-series, but it's sort of link between the two. :)
Comment: So it's not actually part of either series?
Comment: This can't be true - Krillin recognizes Gohan as Goku's son in this movie.  He doesn't even find out that Goku has a son until the first episode of Dragon Ball Z.
Comment: @Zibbobz Re-read the quoted part. The events of the movie can be placed before the Vegeta Saga, so after Raditz comes to Earth.
Comment: @Alenanno That makes even less sense.  Gohan was kidnapped the day that he was introduced to Krillin, and Goku was killed in the rescue efforts, not coming back to life until Vegeta had already arrived on earth.
Comment: @Zibbobz True, the placement creates a few discrepancies with the other two series, [and they are known](http://dragonball.wikia.com/wiki/Dragon_Ball_Z:_Dead_Zone), but then again, movies from anime series often show such discrepancies. Nothing new there.
Answer: All of the Dragon ball Z films Were fillers.
Except these movies:

Bardock: The Father of Goku
The History of Trunks
wrath of the dragon (Very questionable)

Edit: In most cases it does not really matter, because the information is not synchronized with the series itself.


What supermarket fish is good for frying, besides tilapia?

Question: I've been frying tilapia fillets in flour for a while and I like it, easy and tasty, just getting a bit tired of the same fish. Is there any other fish available in most supermarkets that is just as good for frying (I know some fish can't be fried easily)? I'm not looking for any exotic dishes, just some basic fried fish fillets to mix things up a bit.
Comment: What country are you in?
Answer: Farm-raised fried catfish is very popular in the US South, and not much more expensive than Tillapia.
Answer: In addition to catfish, basa (a Vietnamese catfish) fries very nicely, as does haddock or cod.  Basa has the advantage of being inexpensive as well.  Any firm white fish is a good candidate for frying, for that matter.
Answer: Tilapia is actually a bit on the delicate side, so if you're able to pan-fry it to your liking, then any fish as firm or firmer would be good.
Trout or milkfish (bangus) are both quite delightful pan-fried. A very popular breakfast or brunch in The Philippines is daing na bangus, the same recipe pairs brilliantly with trout as well. Consider leaving the skin on :)
Another thing to try is asking your supermarket fishmonger for belly cuts; halibut belly is positively amazing pan-fried. I use cold-pressed grapeseed oil for frying fish because it's so flavor neutral and has a very high smoke point, but vegetable or palm oil would work just as well for the recipe I linked above.
Anyway, in short - go for the denser, meatier fish. Use a good quality and healthy oil. And don't be afraid to try searing it in a pan and finishing it in a hot oven. If it feels like it's going to flake more easily than tilapia, you're probably going to need some practice before you can start and finish it in a pan.
Answer: These are high quality fishes you can fry at home:  silver pomfret, grouper, mullets, black sea bream, red snapper, carp, and tilapia.


Do food items have any point in Fallout?

Question: There are so many food items in the game, but they all only add 1 or 2 HP plus Rads. Is there any reason to use them? Seems the same with healing powder. And why do they 'wear off' after a while?
Answer: That +1 or +2 you see are actually how much they heal per tick. Essentially, they're heal-over-time items. So when you see +1(20s), this means that you recover 1 health per second for 20 seconds, or 20 health total. This means that health items tend to be the best healing items you can find since they're not as expensive as Stimpaks, which should be saved for emergencies or when you get limb damage.
When playing on Hardcore, food items become even more valuable as traveling the Mojave will incur hunger. As you get hungrier, your stats are reduced and you will die when you reach 1000 Hunger. Eating food will reduce your hunger, keeping you alive in the Wasteland.
Comment: Just to clarify: hunger is only apparent in New Vegas. Even on the hardest setting you'll never get hungry or thirsty in Fallout 3
Answer: I'm currently playing a profile on hardcore for the first time and food is necessary, no question. But I find food very useful at times in normal mode. I typically don't carry all my food because of weight but I would always keep a few items that give a good amount of health. I save my Stimpaks for when I'm in combat, when I have broken limbs, or if theres no other source of health. Like Robotnik said, they're a lot cheaper than Stimpaks. And food is pretty much the most commonly found source of health


Does the phrase "The hills have eyes" predate the movie?

Question: I'm under the impression that the phrase "the hills have eyes" predates the movie (including the 1977 one), but I can't find any use of it on Google.  How can I find out if the phrase existed first?
Answer: I found an earlier appearance in the 1904 novel Beverly of Graustark by George Barr McCutcheon. This is on page 39:

Even the hills have eyes and ears.

The Oxford Dictionary of Proverbs has similar phrases going back a long way, but not "the hills have eyes" specifically.
"The fields have eyes and the woods have ears" is used by Chaucer in The Knight's Tale:

But sooth is seyd, go sithen many yeres
  That "feeld hath eyen and the wode hath eres."

But the origin is older even than that. A thirteenth century manuscript in Trinity College, Cambridge has Veld haveð hege, and wade haveð heare with the Latin translation Campus habet lumen et habet nemus auris acumen. At about the same time, it appears in the work of the German poet Reinmar von Zweter: Walt hat oren, velt gesiht.
"The walls have ears" is traced to 1592 (G. Delamothe, French Alphabet ii. 29), linked to the French parallel Les murailles ont des aureilles. This may be the oldest form of all: it appears in the Vayikrah Rabbah (c. 5th-7th century) as

The road has ears, aye, the wall has ears!
Comment: Great answer! All assiduously tracked down, plus I like the way you show how the whole 'family' of related phrases can drift in and out of currency.
Answer: In the past, even perhaps, today, goat herds and sheep herders knew well the ideal green pastures on top of hills and in the valleys around villages, they used to call the flock of sheep or goat to gather. By way of echoes the valley transmitted the sound of the herder, and his flock would hear it and come to him. Hence, old men of the villages in N Lebanon say that "mountains and valleys have ears" since they transmit the sounds by way of echo. That what they believe only.
About "walls have ears": Lebanese famous author Anis Freyha, said that the source of the saying: "walls have ears" derived from  Ludovico Ariosto, Italian author and poet who died in 1533 (in Lebanese:  الحيطان إلها آذان  (walls have ears). I included the translation into Arabic / Lebanese.
الحيطان إلها آذان (أو ذَيْنَين)  (أنيس فريحة:1496 ص281) القول "للجدران آذان" هو للشاعر الإيطالي لودوفيكو أريوسطو، أواخر الجيل السادس عشر. (أردني: "الجدار لها آذاني").
Moreover, another idiom:  الليل له ذينين (the night has ears) is local, I reckon, and many do believe that during night time a minor conversation can be heard from long distance. Now therefore, silence during night time, would allow us to listen from long distances. Please let me know if that helps.
S A Moubarak
Comment: Be aware that ***herbage*** is common slang for the various *cannabis* spp., especially in their leafier and more floral forms.  You might prefer *foliage* or *vegetation* instead.
Comment: I like this answer as it explains that the idea of hills, valleys, and mountains having eyes and ears is a universal one and predates a 1970s occidental film.
Comment: The word "herbages" is replaced with "green pastures".


Not enough space to adjust the caliper

Question: Today I have noticed that when I push the rear brake lever (hydraulic disc brakes) the rotor is a little bit bending , but it wasn't rubbing the caliper . I came to a conclusion that rotor is not centered in the caliper , and I tried to center it . I took the pads out , pushed the pistons , installed the pads back and even if I push the caliper all the way into the frame there is very little space between the inside pad and the rotor , and very big between the outside.
How can I solve this problem so that the rotor stands right in the middle of the caliper , I think this will also improve the braking power. I though to put some spacers between the frame and the rear adapter , but I am not sure if it is a good idea or no.
Comment: A picture here would help :)
Comment: If you can avoid using spacers it's best to do so, but Shimano (used to?) make small spacers for this exact purpose.
Answer: Depending on your brakes and their design, you may not want the rotor centered.
If both pads move when the lever is squeezed, then center position is correct.  However, if you have one fixed pad and one pad that moves you want the rotor to be as close as possible to the fixed pad (without touching/rubbing) so that it bends the least when the one moving piston is engaged.
Most brake manufacturers design their brake calipers with slotted grooves so that the brake unit can be adjusted.  Some Magura breaks are an exception to this and require you to adjust the rotor with spacers.  However, for most disc brakes, if you have the proper adapter and true rotor, these slots should be all you need to adjust the unit properly.

Not enough space to adjust the caliper


SMEStorage with Dropbox on the iPad

Question: I was looking around for ways to get my iWork documents from iWork into Dropbox; going through a forum post on the dropbox website I came accross SMEStroage do any of you use this? If how does it work?
Answer: SMEStorage is a cloud storage service, similar to DropBox itself. In the scenario you are referring to, you can use the SME Storage API directly to upload to an external file provider like DropBox.
Effectively like DropBox you can store everything on the SMEStorage Servers and then access it from any OS/Device as long as you have an internet connection.
From reading the documentation it is really a more advanced DropBox service, which allows developers to use their API to have a central point for accessing various storage options.
From what I can determine, like iCloud, the application needs to support the actual API and interface to be able to store data through it, and since iWorks on iOS only supports iCloud, I am not sure if it will solve your problem.
Answer: I use SMEStorage to edit and save my DropBox, Google Docs and SkyDrive documents with iWork on iPhone and iPad (although it support many other Clouds).
If you buy the SMEStorage iOS App (called iSMEStorage) then you can add the Clouds to it that you want to use with iWork (or any other WebDav client)  to the App and when you launch iWork you use the URL https://WebDAV.SMEStorage.com to then access your Cloud files in iWork.
Clouds added to your SMEStorage Account are WebDav enabled by an access layer that SMEStorage refer to as CloudDav.
Answer: Can validate that SMEStorage will enable you to not only access your DropBox Docs directly in iWork but also edit and save them. To add to the previous answer by Carl, you don't need to purchase iSMEStorage to get this feature, you can sign up for a free account and pay a one time $5 fee for the CloudDav product (http://smestorage.com/?p=static&page=CloudDav)

SMEStorage with Dropbox on the iPad


Why destroy bitcoins?

Question: I keep seeing references to destroying bitcoins by sending them to addresses that nobody can own (e.g., addresses derived from impossible public keys). What would be the reason for doing this? It's discussed in such a cavalier manner in various posts that I'm assuming it's not an attempt to undermine the currency.
Answer: A non-malicious reason to deliberately destroy notable amounts of Bitcoins would be for a hypothetical alternative blockchain that recognizes Bitcoins sent to a special address as newly generated coins. One could for example try to establish a new "Altcoin" which is incompatible to Bitcoin, but every private key that signs a Bitcoin transaction to a special impossible Bitcoin address is eligible to also spend an according amount of Altcoins. This would enable a secure one-way conversion to a separate blockchain without the need for exchanges.
Answer: Certain escrow techniques rely on one party being able to "destroy" these bitcoins, without being able to steal them. For example I could put 10 bitcoins in escrow, giving a second person the ability to destroy them. Now if that second party lends me, say, 5 bitcoins, I can't simply run away from my debts without incurring a loss larger then the debt itself, once the other party destroys the bitcoins. There are variations of this scheme for a number of other purposes.
You don't want to actually destroy bitcoins in such a scheme, but you want the threat of destroying them.
But "destroy" in this context isn't necessarily an actual destruction, as long as "destroyed" bitcoins are a loss for both parties. Donations to trusted organizations are an alternative.
Answer: I don't think anyone is intentionally destroying large amounts of Bitcoin.  Some relatively large amounts have been destroyed accidentally, due to hardware and software failures.  This thread is an attempt to count all the lost Bitcoins.
Don't forget that each of the 21 million total Bitcoins is divisible into 100 million parts.  So it's considered that there's plenty to go around, and the more that is destroyed, the more the remaining ones will be worth.
Also, don't confuse the term "bitcoin days destroyed" which is sometimes used with destroying the coins themselves.  This "days destroyed" measure is sometimes used as a measure of velocity in the bitcoin economy, and doesn't really measure destruction of anything.  If you have 10 bitcoins for 7 days in the same place, we can say they have an age of "70 bitcoin days".  If you spend them, the new coins will have an age which starts again from zero.
Comment: I think this is the wrong answer. There are actually schemes that rely on being able to permanently destroy bitcoins (don't know enough about it to write an answer myself though).
Answer: There have been at least one message services / blockchain tattooing services that will make an unredeemable(?) TX to a vanity address.
If one were to have enough hashing power and time, theoretically you could recover keys for lost or destroyed coins. A lot of time. ;)
Comment: I don't think that's necessarily true. What I've seen is that destroying bitcoins means sending them to invalid addresses. No amount of processing will undo that, right?
Comment: It would take a lot of time, using current tools. Think heat-death of the universe.  On the other hand, if a shortcut is found, then it could be used to steal anyone's bitcoins from the block chain.

Why destroy bitcoins?