Should I list all my research on a CV? Or should I only put the most significant medical research trials?

Question: I am updating my CV and applying to jobs in medical research. I am wondering if I should put all the trials that I have worked on with various other doctors or just the most significant ones?  I have like 40 research trials I have worked on and it seems immodest and overdone.
Comment: Yes, you should list all your published papers.
Comment: CVs are not a place for modesty. They're where *all* the facts go about you!
Comment: Are you making a distinction between "research trials" and publications? In general, the emphasis is typically on publications and grants and less on "projects that you worked on".
Answer: Ah, this is a good question!
Unlike a resumé, in which one includes only the experiences/skills that are relevant to the position being applied for, a CV is meant to document all  reasonable academic endeavors and accomplishments. In some cases, lines on your CV will be only loosely related to your main research interest; my CV for instance includes several co-authored papers I am not particularly keen on.
I don't know that there is any hard-and-fast 'rule' stating your CV must be complete, good and bad, but it has been my impression over the years that one includes pretty much everything.  If you've ever wondered why your department chair's CV is 35 pages long, now you know why.
Answer: As far as I know, professors, senior researchers and alike have two resumes: a short one (1-3pages) listing main milestones, and a long one, which can be up to 50pages (longest I have encountered), listing all and every thing they did.
Comment: I have seen 200-page CVs.
Comment: @JeffE Indeed, not that surprising (admirable, though).


Windows 8 MPG codec

Question: Is there any chance to get an MPG codec only for Windows 8 somewhere, instead of all those free multiple codec packages I don't trust so much?
Comment: Why don't you trust those packages? I'd say use the built-in Windows 8 store if you want something vetted (well, I *assume* it's vetted by Microsoft). An individual codec out on the net somewhere is no more trustworthy than a pack of codecs (arguably less, if you're comparing it to a popular codec pack like CCCP).
Answer: Download Codec Installation Package. This package can be used as an alternative to automatically downloading Windows Media Codecs, or to correct problems experienced with previously-downloaded codecs. LINK.
*Install only codecs, filters, or plug-ins from trusted, authorized sources, such as the website of the official supplier. Even then, use caution: some codec suppliers offer minimal customer support. Before installing any digital media components, set a system restore point. The restore point enables you to return to your original system configuration, if necessary. And I think this link is trustable. If you are worried, just create a restore point before. LINK.
Answer: The Media Center pack for Windows 8 adds MPEG codecs to the operating system. There was a limited time offer when the upgrade was free, but not anymore. If the media center pack is installed, then Windows Store apps are able to use the MPEG codecs as well (not available on Windows RT).
The 'Codec Installation Package' linked in the answer above does not contain MPEG codecs - just Windows Media codecs (which are different from MPEG)
If you want a free solution, my recommendation is to get FFDShow: http://ffdshow-tryout.sourceforge.net/
Comment: It's all well and good with "normal" Windows where codec packs can be installed, but is there any possibility of expanded codec support in WinRT? Would have been nice if XBox Music, Video and the like supported at least common codecs such as FLAC and MKV out of the box. I know third-party solutions exist (both free and paid), but why do we need to switch to them when audio/video apps of a certain standard are already available out of the box? The price for the codecs could have been included in the device's price. This step-motherly treatment for WinRT is irritating. (Sorry for the rant. :)
Comment: @Karan: Adding additional codec support is always being considered, but has to be prioritized relative to other features. Adding codec support isn't always just a matter of licensing cost - often it is the supporting/servicing cost that is prohibitive (especially because of legacy compat). WinRT is a priority, but it is also a rare opportunity to start with a clean slate and limit legacy (and number of) components to guarantee a solid quality experience. It has been a conscious decision to concentrate on MP4 since FLAC/MKV is more enthusiast than mainstream (I realize this is slowly changing)
Comment: I wouldn't exactly term them "enthusiast"-only now. A few years back, perhaps, especially with little hardware support out there. Now? Even cheap video streamers/media players support these containers/formats, not to mention the millions of mobile/other small form factor devices out there. It would have been nice for MS to have been a bit more forward-thinking in terms of WinRT at least, since we don't even have access to desktop apps. In many ways it does look to the future, but in others it's oddly mired in the past or stuck in the present (which in tech terms is the past in no time at all).

Windows 8 MPG codec


DEM interpolation, QGIS 3.10

Question: A friend of mine gave me DEM resolutions of cells 5x5m, but there is something wrong with interpolation. When I try to make a cross-section of the terrain I get a pretty inaccurate cross-section, with weird peaks and valleys.
What should I do to get a smoother DEM?
These are the extensions:

cross-section (There is no waterfall there :-)
Comment: Honestly, looking at the DEM I see no way to fix this aside from generating it again from the original data with a different method. Ask your friend for better data.
Comment: It looks like it is a patchwork of different sources. The bottom of the valley seems derived from hypsometric curves while the hills/mountains around look like a TIN. They transition badly where they meet, and the TIN seems full of artifacts or bad sample points. I hope you're not doing hydrology!
Comment: You think it is not completed or the DEM is damaged? I think that this DEM is generated with some kind of triangulation
Comment: Not directly with hydrology, but with geomorphometry :-)
Answer: The DEM seems to be the result of a Triangulation based on points and lines (probably ArcGis TIN algorithm). One thing that you can do is correct the value of the wrong cells using the Plugin Serval that allow you to change "manually" the value of any pixel. In the case of your DEM I think that the amount of the wrong pixels is small and you can try this approach.
I suggest visualising your DEM with Pseudocolour Singleband that exalts the presence of pixel with different values from the surrounding area and, with the Serval tools, just proceed using the Probing mode tool to extract the value of a near pixel and copy in the wrong pixel with the Drawing mode tool.
Comment: I can understand. Another possibility could extract the contours, remove the smallest parts of them with the Simplify algorithm and recreate a DEM from the cleaned contours. But I am not sure of the result without doing some attempts with your DEM.
Comment: I think there is a lot work to do. There are many mistakes to manually correct.

DEM interpolation, QGIS 3.10


Can a deleted file on an SSD with trim enabled be recovered?

Question: I'm just wondering from a security stand point if a deleted file on an SSD with trim enabled can be recovered? I've did some research and it would seem it is impossible unless for some reason trim wasn't called on the deleted file blocks.
Comment: Have you read the questions tagged with `trim`? and the questions in the "Related" section to the right on this page?
Comment: If you're looking for a guarantee either that it can or that it can't, you're very likely to be disappointed.  Even if you limit your question to a specific model.  How quickly the data is actually erased probably depends on how large it is and what else shares the same erase sector.
Comment: The file (movie) was around 10 mb. So it wasn't too big.
Answer: Deleting data with trim does not securely delete the data.
The trim command tells the drive's controller that certain logical sectors of the drive are not being used and that their data MAY be treated as erasable to aid performance.
In normal operation, these sectors may be wiped by a future write operation (or rather, wear-leveling in preparation for future writes).  But this is not guaranteed to happen immediately or within a given time frame.  With access to the physical drive you may be able to obtain the data from the flash chips before they are erased.
Even overwriting the data does not securely delete it on an SSD, because of wear-leveling and overprovision.  You can only securely delete data on an SSD if you use a secure wipe, a function that needs to be supported by the drive and which would erase everything.


What keyboard shortcuts are available when editing questions and answers or otherwise interacting with the site?

Question: I like keyboard shortcuts. What keyboard shortcuts are available when editing questions and answers or otherwise interacting with the site?
Comment: [There's also a fantastic userscript for chat commands](http://stackapps.com/questions/2105/se-chat-modifications-keyboard-navigation-and-commands-for-chat)... an absolute must if you use chat. (It does so much more than just chat keyboard modifiers!)
Comment: You might want to consider copying your question into an answer, and rewriting the question as "Are there any keyboard shortcuts when editing questions and answers?". Then we can tag this as [tag:faq]
Comment: @Josh Okay. Good idea. I've restructured the question so that the actual content is in the answers and hopefully it invites you and others to add other keyboard shortcut tricks in the answers.
Answer: Shortcut keys for editing questions and answers
Originally posted here: For those who like such keys but hadn't noticed them, here's a quick summary of what those available for editing questions and answers  and when they are useful.
They are displayed when you put
your mouse over the toolbar icons.

The following is slightly OSX centric. In that context all the commands work in theory with either Command or Control as a modifier.
Although existing shortcuts assigned to Cmd can prevent the command option from
working.
While it makes sense to include shortcuts for each formatting option.
Only some of the shortcuts offer an efficiency benefit.
Useful

Cmd+L for hyperlink dialog box; selected text is used as the link text. It
produces refernce style links. I generally prefer inline links.
Control+Q for quote; Cmd+Q conflicts with Quit application, so Control+Q
is required
Cmd+K for code: converts selected words on a line to formatted inline code
(i.e., surrounded by backticks); converts selected lines to formatted code
block (i.e., four space indented)
Cmd+G to insert image; tab, space, escape, etc. work for navigation of the
resulting dialog box.

Marginally useful

Cmd+B for Bold
Cmd+I for Italics
Ctrl+R insert horizontal rule

Not needed

Cmd+O to start numbered list; this isn't very useful, because it's not that
difficult to start a list and it doesn't convert a highlighted set of lines
into a list)
Cmd+U to start an unordered list; same point for number lists
Cmd+H to insert heading. This also isn't that useful given how easy it is to
insert


Is eating penguin halal?

Question: Is eating penguin meat halal or is it haram?
Comment: If you have to add filler to satisfy the length requirement of stack exchange then make it relevant to the question, i.e. elaborate what you are asking. Don't put in irrelevant gibberish.
Comment: Unclear and incoherent question. Are you asking about the Vegetarian ruling or the Islamic ruling? If it is the first then you are in the wrong place as we only answer based on the teachings of Islam and not based on other moral compasses. And if you are asking for the Islamic ruling then I am puzzled as to why most of your post talks about what vegetarians think. Islam is not vegetarian as it permits and even [prescribes](https://quran.com/22/36) eating meat and sacrificing cattle.
Comment: No actually stackexchange wanted me to put more characters so i copy some  stuff. But my question is about penguins ;
Answer: The default rule about food in Islam is that everything is halal except when there exists specific evidence that makes something haram. This is because of the general meaning of the verses such as:

هو الذي خلق لكم ما في الأرض جميعا
It is He who created for you all of that which is on the earth.
— Quran 2:29

قل لا أجد في ما أوحي إلي محرما على طاعم يطعمه إلا
Say, "I do not find within that which was revealed to me [anything] forbidden to one who would eat it except ...
— Quran 6:145

وما لكم ألا تأكلوا مما ذكر اسم الله عليه وقد فصل لكم ما حرم عليكم
And why should you not eat of that upon which the name of Allah has been mentioned while He has explained in detail to you what He has forbidden you
— Quran 6:119

There is no evidence which excludes penguins from these texts. They are not named in the Quran and Ahadith, they have nothing in common to the haram animals, they do not hunt with their talons etc. If this is established then they should fall into the default rule and be considered halal.

Ref:

وأما البطريق فلم نجد له ذكرا فيما وقفنا عليه من كتب الفقه القديمة
والظاهر أنه لفظ عجمي معرب
وقد عرفنا أنه طائر برمائي، وأنه غير مفترس، وإذا تقرر ذلك فالأصل في أي
حيوان أنه حلال ما لم يرد دليل يمنع من أكله
وعليه, فلا نرى حرجا في أكل لحم البطريق
والله أعلم
— Islamweb
Answer: In Shiite jurisprudence, the general scholars do not consider it permissible to eat penguins. Although penguins are considered birds, they do not have halal meat conditions and are not allowed to eat them.
Birds: Halal birds have two signs of meat, and other than that, all types of birds are haram meat.
1- Birds that fly more wings during flight and open their wings less and keep them straight are halal meat; But birds that open their wings more and keep them straight and fly less and fly less (move their wings less) are forbidden to eat meat.
2. Birds that have stratifiers or gills or thorns on the back of the foot are meat solvents. (Note: Birds that are like hawks, eagles, and hawks that have claws are forbidden to eat meat.)
https://www.islamquest.net/fa/archive/fa38791
https://www.islamquest.net/fa/archive/question/fa2290
Comment: But shiism is wrong ; and many times condracit Quran ; and sunnah

Is eating penguin halal?


I play a game called Fortnite. There are two elements in it shield potion and magic carpet

Question: In this game by drinking the shield potion your character gets some extra HP which works as a shield before your actual HP is starting to lose. And there is a magic carpet which works as a trampulin and makes you jump higher. I know that magic is haram. So, by using these items in this game also haram or it is Ok? Keep in mind that potions are magical substances like love potion etc
Comment: What about the magic carpet which makes you fly?
Answer: Games are often places where people do what you must not do in reality.
Restrictive schools refuse reality-like games in general (haram)
Reality games where you do what in reality is forbidden are at least maqruh (not recommended).
"magic" elements like drinking love potion in theater or fiction is not a problem as long as nobody claims it to be reality.
Comment: Please consider supporting your claims by evidences.
Comment: I will try to assemble an overview over fatwas and publications on pictures, animation and related. There are different opinions on this topic.


Would like to change an existing outlet to half-hot

Question: I have an outlet that is fully hot. I would like to make it half-hot instead. There are only TWO wires total going to the outlet; one white and one red. Is it possible to make this outlet half hot with only two wires?
Comment: What do you want with the other half?  Always cold (off)?  Switched by a nearby switch?
Comment: I really don't understand the question.  We need details - What country, a clearer explanation of what you want.
Answer: with only 2 wires you wont be able to control the 2nd half. If you just want to cut the power to the 2nd half turn the power off pull the outlet and break the tab between the 2 outlets on the red side. if you want to switch the other 1/2 you will need to pull a wire from the red to a switch and then back to the half you want to switch. You should also run a ground from the outlet to the switch.


How do I move Steam games from one computer to another without downloading them again?

Question: So recently I got a new PC, mainly for gaming. I gave my old PC to my brother. Now what I am having trouble with is getting my old steam games on to my new computer, without having to download them. On any other occasion I would have just downloaded them but I live in a very rural area so my internet is pure shit. That being said I also won't be able to share the files over the Internet. So those aren't valid options. All the flash drives in my house are way too small for transporting any games. So there's my question, how do I get these games to my new computer without sucking up all my family's bandwidth and this months Internet?
Answer: Assuming your brother is still living in the same house, you can easily transport them directly over your local area network. I don't know what version of Windows (or other OS) you're using, but it should be pretty doable with a Google search of "(your OS name here) local network file transfer." This utilizes the local connection between the computers in your house to transfer files, cutting out the Internet as a middleman. If you don't have a LAN set up at your house, your cheapest option is a regular Ethernet crossover cable run between the two of your desktops.
Once you've got the files in the place that you want them, you can go into Steam and add the folder you've copied your games to as an install location on Steam so that they'll show up in your library. By default, Steam doesn't look for any games on your computer outside of its install directory, but you can easily add new locations for it to search for games. This guide explains it fairly well.
You can also create a new location for Steam to download games to when you want to download a new game, if you want, or even use the same place that you copied your games to. In fact, I recommend this. I don't know how finicky Steam's metadata detection is (read: how well it knows whether or not the game folder you copied is registered with Steam) but your safest bet is to copy all of your game folders exactly as they were on your old PC into a new folder on your new PC. For example, let's say I installed Steam in C:\Program Files\Steam. I would go to C:\Program Files\Steam\steamapps, which is where the actual game content is stored. I would look in the subfolders (some of your games may be in either your username folder or "common" -- check both) and copy those game installations exactly as they are into a pre-existing games folder on my new PC; for instance, C:\Steam Games\. Then I would add C:\Steam Games\ into my library folders using the guide I posted in the last paragraph. I actually put my Steam games on an external hard drive, and I can freely plug and play the drive and play all of my Steam games no problem.
Hope this helps!
Comment: Thanks for the answer!!! (I'm actually surprised in how fast I got one!!) I'll give this method a try and get back to you if I have any further questions.


Can you identify this plant with toothed leaves?

Question: Are you able to identify this plant that is in my front yard? It is about 70cm high at the moment, and grows out in separate stems that come out from the ground that you see here. I live in Melbourne, Australia. Thank you
Comment: Quite possibly Banksia. (B serrata? integrifolia?)
Answer: Maybe Banksia prionotes, common name Acorn banksia - see what the flowers look like when they arrive. Image and info here https://www.bgpa.wa.gov.au/about-us/information/our-plants/plants-in-focus/2712-banksia-prionotes
Comment: Thanks @Polypipe and Bamboo. After some obsessive searching last night I came across Banksia spinulosa var. collina which I think might be it. If it ends up with those candlestick flowers I won't be removing it.


Tax Reform - Make people's tax cut permanent first instead of corporations?

Question: I know that if there had been 60 yea votes for Trump's Tax Reform (Byrd Rule), that regular people would have also had their tax cuts made permanent along with corporations.  What I want to know, instead, could the people's tax cut have been made permanent, while corporations were not, and then a new bill such as Senator Ted Cruz's has proposed to make the cut permanent?  Also, was there a reason that one was made permanent and the other was not, or how was it decide which would be?
Answer: The reasons that corporation tax cuts are permanent and personal ones aren't is math. Corporations don't pay that much tax compared to total revenue, so cutting them even by significant amounts doesn't create a significant change. Personal income taxes on the other hand is the largest source of revenue for the government so even small changes have a significant impact.
The Byrd Rule would prevent permanent changes to personal income tax cuts because its basically impossible for them to not be considered significant according to how these calculations are done. Corporate income taxes aren't enough to actually trigger this so they could be made permanent. A future bill could make the cuts permanent, but that would require 60 votes which is not possible given the current environment of obstruction and refusing to compromise.
None of this really matters beyond creating political talking points. The system used to calculate increases/decreases in deficits isn't really grounded in reality to start with, and changes will happen that make any predictions totally irrelevant anyway well before a 10 year time frame is met.
Comment: Actually it's a bit of politics. No one wants the taxes to be raised on middle class people so extending them could be easy to accomplish so no reason to make them permanent. Corporate taxes were made permanent so they can't expire, democrats would have to vote to (Noooo!) **raise taxes** which plays into the Republicans hands of *no taxes for anyone* - Democrats can never raise them or the fact that they increases taxes will be used against them in the future.
Comment: @HannoverFist It gives political points both ways, making corporate taxes permanent makes you look like you favor them over people. It also doesn't really affect that much because almost every president in recent history signed significant changes to tax law.
Comment: This is a bit circular.  The reason why corporations don't pay much of the total incoming revenues is because their taxes are low due to previous cuts. So claiming that it's easier to cut theirs because they don't contribute as much because they've already had tax cuts before..... that's more the goal than the reason. http://www.nbcnews.com/id/29861648/ns/politics-capitol_hill/t/how-tax-burden-has-changed/
Comment: @PoloHoleSet its not circular. The reason corporations don't pay much in total tax is because most every economist agrees taxing corps is inefficient. Its also low because big corps aren't a major part of the economy if you only look at the balance sheet. the sheer number of small and midsize businesses combine to overwhelm them in terms of economic activity and most of it get taxed through personal income.
Comment: @Ryathal - did you bother looking at the link?  Corporations and business taxes used to contribute a lot more in terms of share of overall tax revenue.  That was reduced through changes that were based on supply-side concepts.  The reason why they don't pay as much is because the laws changed to tax them less.  Whether you agree that it's the wisest way or not, now claiming that it's because of their share of incoming revenue, when incoming revenue is something that gets set by tax policy, is completely circular.
Answer: You ask several questions.  Some answers

They could have done it the other way around if they wanted.
Yes, a subsequent bill with 60 votes in the Senate could make the currently temporary tax cuts permanent.  In fact, that's the stated plan.  Someday.
The reason they did it this way is that they don't believe there are 60 votes for a permanent corporate tax cut.  So they made the unpopular changes (tax increases and tax cuts for unsympathetic recipients) permanent and made the popular changes temporary with the idea that they would later fix the popular changes.
This was in large part a response to what happened with the "Bush" tax cuts.  They were passed via reconciliation and 75% of them were made permanent.  But 25% were not.  They don't want their tax cuts to disappear like that again.  They are confident that they can get 60 votes whenever necessary for the tax cuts that were temporary.


Second Order Differential Equation with Polynomial Coefficient

Question: Can someone suggest a way to solve the following differential equation
\begin{equation}
(1+\frac{z^2}{ 2q})^3F''(z)+(\frac{3-4p}{2q}) (1+\frac{z^2}{2q})^2 z F'(z) +\epsilon F(z)=0
\end{equation}
where $-\infty<z<+\infty$. The solution $F$ when multiplied by
$(1+\frac{z^2}{2q})^{-p}$ is expected to converge to zero when $z$ goes to infinity. In the present form this equation does not admit a polynomial solutions. Any suggestion is appreciated.
Comment: What are $p$, $q$, and $\epsilon$?
Answer: The only case for which I have been able to find a solution corresponds to $\epsilon=0$.
Reducing the order, we have
$$F'(z)=c_1 \left(2 q+z^2\right)^{\frac{4 p-3}{2} }$$ from which
$$F(z)= c_1\,(2 q)^{2 p-\frac{3}{2}}\, z\, _2F_1\left(\frac{1}{2},\frac{3}{2}-2 p;\frac{3}{2};-\frac{z^2}{2 q}\right)+c_2$$
Could the problem be relevant of perturbation theories ?
In any manner, without boundary conditions, I do not see what else I could do.
Comment: Actually this equation arise from a problem in quantum mechanics. The case $(p=q)\rightarrow \infty$ yields the Hermite equation for which polynomial solutions exist for $\epsilon=2n$. For arbitrary $p$ and $q$ still one expects a discreet set of values for $\epsilon$ (much like Hermite equation) but I don't see how that naturally comes about


I'm doubling lemon juice in a no-bake pie recipe to make it extra sour. What can I add to make it less goopy?

Question: Every year my partner makes a lemon pie, and every year her guests want it to be more sour than the last. Last year we put in way more lemon juice than the recipe called for, but it came out a goopy mess. What can we add to get the pie to hold its shape? Is there any way to make it more sour without just adding more lemon juice?
Comment: What are the other ingredients in the pie? What do you use to set it?
Comment: related: https://cooking.stackexchange.com/q/20701/67 ; https://cooking.stackexchange.com/q/62183/67 ; https://cooking.stackexchange.com/q/114516/67 ; https://cooking.stackexchange.com/q/28047/67 ;
Comment: More lemon juice may curdle the dairy ingredients.
Answer: More lemon juice is more liquid, which is likely the cause of your problems.  If there's any other liquid in the recipe, you can try swapping it for the lemon juice, but it's possible that it might provide something else to the recipe that lemon juice can't provide.
You can try adding something else that's sour (tamarind, sumac, etc), or specifically buying powdered citric acid.
I would also recommend zesting the lemon (only the yellow part, avoid the bitter white pith) to help increase the lemon flavor without adding more liquid.  You can also buy food-grade lemon oil or lemon extract.
Comment: While the zest (and especially lemon oil or extract) are great for more lemon flavor, they don't provide much towards sourness
Comment: When purchasing citric acid for food use, make sure it is food-grade. I've only ever seen that grade where I've looked (it is also good for descaling kettles, shower heads, etc.), but better safe than sorry.
Comment: Sumac and tamarind have flavors (and colors) of their own, but they'll probably be really good.
Comment: @AndrewMorton: Excellent point. I use non-food-grade citric acid as pot cleaner (with really good rinsing). Why people kept storing the pots unrinsed so they grew mold I have no idea.
Answer: A few suggestions:

Add lemon zest as well as the juice; this is often a better way to convey lemon flavour. I would mix it with the sugar a little while before using it to help extract the essential oils, and maybe sprinkle some zest on top so that it contributes to the smell when the pie is being eaten.
Reduce your greater amount of lemon juice to the right volume of liquid by heating it for a while in a wide-bottomed saucepan. I can imagine this will affect the flavour but it shouldn't reduce the sourness if that's what you're going for.
Experiment with reducing the amount of sugar, which does affect perceived sweetness. However, this could also have an effect on the general structure of your pie (and I assume you still want it sweet).
Add lemon essence to the recipe, much like you might use vanilla essence in a sponge cake.
Comment: I don't think your #2 will work.  Reducing lemon juice by heating it drastically cuts its sourness, in my experience, much faster than it boils off any of the liquid.
Answer: One possibility would be to add lemon zest (for lemon flavour) and then lime juice (rather than lemon juice) - or a mixture of lime and lemon juice. Lime is more acidic than lemon.
If you don't mind a slightly artificial flavour, you could (as others have suggested) add citric acid - dissolve the powder in around the same volume of liquid (in this case perhaps in lemon juice). There are also bartender's products like supasawa which will do the same thing and allegedly taste less artificial due to the use of multiple acids.
One problem you might be having is that the acid is preventing the setting of the pie. I doubt this is the issue as many such recipes rely on the acidity (through curdling). But if so, perhaps look for tarte au citron recipes that work well with acid.
Answer: Much depends on the rest of your recipe, but you could experiment with Amchur/Amchoor, dried and powdered unripe mango. It is fruity but sour and is also used for its thickening properties:

As useful and wonderful as lemons and limes are to livening up long-cooked dishes, they can get a little old. Amchoor has the tartness of citrus and all the flavor of its zest. Like citrus juice, it's best added at the end of cooking to preserve its flavor, but should be stirred well into whatever its coating. Similarly, it can also cut the cloying sweetness of fruit-based sauces, syrups, and compotes. It makes an interesting addition or alternative to the medieval triad of cinnamon, clove, and nutmeg.
It has one other advantage over lemons and limes: It adds no liquid. If you want to add tartness to some roasted vegetables or fried items while preserving their delicate crispiness for more than a few minutes, amchoor may be your answer.

You might need to be careful in case it adds a graininess, possibly like cocoa powder you need to be careful to make sure it is fully hydrated before you bake, in which case soaking it in the lemon juice might work well.
Answer: You can try adding concentrated lemonade. That will increase the sweetness, so you should reduce the sugar elsewhere. You can also try adding something with a very low pH. For instance, if you can get your hands on some citric acid, you could try that.
Answer: Citric Acid
This is exactly the same compound that makes lemons, and all citrus fruit, sour.  Adding more will allow you to adjust the sourness without changing anything else in the recipe.
60ml (2oz, 4 tablespoons) of lemon juice typically has about 3 grams of citric acid and is about as much juice as you get from a lemon, so to double the sourness you would add about 3 grams of citric acid per medium lemon's worth of sourness.  3 grams should work out to just over half a teaspoon, if that's all you have to measure with.
Citric acid is both cheap and readily available - be sure to get food grade.
A few other answers have touched on this as a passing idea, but it's absolutely the way to go, 100%.  Other souring agents like sumac or tamarind will ruin the lemon flavour - they have way too much of their own personality and will completely throw the aromas off.  Zest and lemon oil will give you a more powerful lemon aroma, but will do nothing for the sourness.

I’m doubling lemon juice in a no-bake pie recipe to make it extra sour. What can I add to make it less goopy?


Is there a tool for managing user stories?

Question: Background on what User Stories are:
The UX of User Stories
part2
An ideal tool would:

Be online
Enable quick collecting of story titles
Enable to map/share/group the collected stories
Allow open discussion around stories
Enable collaboration for collecting stories and elaborating their meanings

I'm quite sure I saw something published recently, but can't find it.
Comment: Good question. Tools I know and have used are more issue tracking tools (http://redmine.org/, http://asana.com/ and http://pivotaltracker.com/). They're not explicitly for managing user stories but they support issues with title, description + comments (-> discussions) and also prioritization.
Comment: Maybe 'idea management' tools or software is a good search term for further research?
Comment: User Stores are part of the Agile process. Research SCRUM and Agile management tools. There's dozens of them out there.
Comment: Sorry to bump a "closed" thread but YET AGAIN this is another example of a thread being closed for no good reason. This is a valid question, it is good for Q&A format and I found it because I typed exactly this in google.
Comment: This question is being discussed on [meta](https://ux.meta.stackexchange.com/questions/3399/please-consider-reopening-tools-for-user-stories-question)
Comment: I could see this question being updated to ask about different processes (that can be supported by tools) for defining (and refining) user stories. Otherwise tool recommendations would be migrated to Software Recommendations.
Answer: There are many tools for this task. The closest I'm aware of that explicitly focuses on users story management is sprint.ly.
Most issue tracking systems have plugins for this purpose too; the two that I use—Redmine and Jira—both have so-called Agile plugins for tracking user stories and managing story points, burndown charts, etc.
Answer: We use Confluence, a great tool for user stories! It works like a Wiki, but with richer UI and functionality.

Be online

Confluence can be used as an intranet and at the same time be accessed outside of the company via Internet.

Enable quick collecting of story titles

Confluence have built in macros like table of content and other useful content containers such as children display.

Enable to map/share/group the collected stories

You can filter content by users, groups, labels and tags, which is shared instantly.

Allow open discussion around stories

Every page have comments, which is threaded if there are many comments.

Enable collaboration for collecting stories and elaborating their meanings

Since it's a Wiki, you can
Answer: Trello is the tool we use. It's a board with lists which contains cards.
User stories and sprints
We write down the userstories as titles of the cards. When all user stories are collected we subdivide them onto the different lists. The lists stand for the sprints. When we begin with sprint 1, we add soms more list next to it: working on, test and done.
Working on, test and done
When a ticket (card) is picked up by a team member, it's dragged to the working on list. After the ticket is ready to test by the client, the tickets is dragged to the test list. When the client approved the ticket, it will be dragged to done.
Discussion around stories
A card can be opened. On the card checklists and comments can be submitted. Very useful for making a task list and keep track of the communication about a user story. Also a team member can be attached to a card so everyone can see who's working on that ticket.
And yes, our clients also use the same board (per project). This way they have a nice inside view in the project.
Comment: Trello is indeed a great tool!
Answer: We've used VersionOne at Western Union Business Solutions successfully for several years.   It supports all of the features you've mentioned and a lot more.
Answer: Checkout https://easybacklog.com/ it's still in beta and while it doesn't exactly hit what you're looking for it does offer a solid structure to agile user stories.
I should also say that I haven't used this for a project. I'm still trying to figure out how to help my company make the shift to agile user stories instead of big requirements docs.


What sets a "Law" apart from a "Rule" or a "Principle"?

Question: Basically, I understand the difference between a "Theory" and a "Theorem" but I am quite confused when it comes to "Law", "Rule" and "Principle". Can you make the differences clear to me?
Comment: @dmckee This isn't really a duplicate. It touches on the definition for Law, Rule, and Theory as well as Principle. The other question only gives possible definitions for Principle. I think this should be re-opened as it has a wider applicability and a different focus than the other one.
Comment: The answer is the same. There are no standardized meanings. These words have been applies willy-nilly at the whim of assorted people over a long history without consistency.
Comment: Related: https://physics.stackexchange.com/q/35660/2451 and links therein.
Comment: If you're unsatisfied with the answers, that's one thing. But I respectfully disagree about this being a "duplicate"
Answer: A theory is a collection of concepts, laws, and equations in science that is meant to explain some particular subset of observations. It's also used for theories describing gedanken worlds that differ from ours. There is also a related word "model" that differs by a theory by being really specific while a "theory" may leave some details adjustable, and "framework" which is on the contrary less specific than a theory and fully determines the general methods, and type of objects and arguments that are allowed in research. The boundary between the terms is not quite sharply delineated.
A theorem is a mathematical proposition, usually a hard one to prove or disprove, and usually a far-reaching and general enough, that has been proven to hold by rigorous mathematical methods. A lemma is a less important version of a theorem, usually one that is used as a step to prove full-fledged theorems.
"A rule" is usually used for some prescriptions that should be memorized and that chooses the right answer from a usually small list of possibilities. In particular, there are right hand rules that determine the sign of some quantities and/or its relationship to directions in space (this direction or opposite direction). Some of the rules define conventions – claims that could have also been chosen in the opposite way but people must understand each other so they agreed to use one particular sign etc. Hund's rules determine which angular momentum is chosen – again, the number of candidates is usually limited.
"A law" is a more substantive insight about Nature, a building block of our understand how Nature (or the society) works. It may be equivalent to one equation, one identity for continuous quantities, like Coulomb's law for the attraction or Ohm's law $U=RI$ etc. How Nature works is described by the "laws of physics".
"A principle" is more general than a law and it is usually a statement of a general type or a philosophy or a condition that good laws (explained in the previous paragraph) are supposed to satisfy. A principle is therefore an extra criterion that has been induced from the observations and the known laws and that is imposed on the new candidate laws. The principle of relativity is an example. Principles usually require more verbal, words-based descriptions to be fully formulated, as opposed to a single particular equation that may define a "law".
Comment: Trawling through Wikipedia, one finds, in addition to Galileo's principle of relativity, other examples such as the [Copernican principle](https://en.wikipedia.org/wiki/Copernican_principle) or [anthropic principle](https://en.wikipedia.org/wiki/Anthropic_principle) that would seem to match the description in the final paragraph of this Answer. Others, such as [Hamilton's principle](https://en.wikipedia.org/wiki/Hamilton%27s_principle) come with a precise mathematical formulation...
Comment: Wouldn't you say that in a formal mathematical theory principles are part of the axioms of the theory, i.e basic initial assumptions?
Comment: +1 especially for the distinction between a law and a principle.
Comment: Dear Anna, I actually can't think of a usage of "principle" in mathematics at this point - although it may be just an imperfection of my brain - even if I could, I think it would be off-topic on this physics server. @Eugene, the principle of least action is something I had in mind when I was writing the answer. Well, $\delta S=0$ is a "specific" formula but only if one develops all the machinery that actually follows from the principle. Without that, it has to be replaced by the particular Euler-Lagrange equations so the "principle" is a general philosophy generating many particular results.
Comment: In the UK, many years ago, I was taught what the textbooks called $the\ principle\ of\ conservation\ of\ momentum.$ Why 'principle' and not 'law'?, I wondered. I note that nowadays 'law' seems to be used as often as 'principle' in this context. 'Law' certainly seems to me to be the  more appropriate word. Agreed?
Comment: @PhilipWood - I generally prefer "conservation laws" like you do because there are many of them and "principles" should be more unique. But when the people knew only a few of such laws, they had better reasons to call them "principles" because they looked grander and more unique. All such things are evolving - the essence and knowledge is evolving, the language must reflect it, and on top of that, the language is evolving independently of the essence, too.
Answer: There is no consistent usage of these words among scientists.
Usually, when someone says "law" or "principle", they are referring to a general idea that has been found to apply to many different situations, but not always. More speculative ideas are generally called theories, but use of the word "theory" does not always mean that an idea is speculative.
All I can say for certain is that you should not make assumptions about whether an idea is speculative or confirmed, general or specific, etc. based only on whether it is called a theory, law, rule, principle, or something else.
Answer: In case you ever have to answer this question in a hurry or are explaining it to someone that might not be able to follow Lubos' answer fully. Let me present a shorter, root version.
A scientific Law is a statement of observations. That is all. This statement may come with equations, but it is always "It is observed in nature that (Given observable) follows (Given pattern/equations) subject to (Given conditions)".
A theory is a statement that attempts to explain observations. Again, that is all. It is not necessary that these observations have been made; a theory may explain observations that have not been made - this is called a prediction. A prediction that is shown to be correct is confirmed and the original theory becomes a regular explanation of the new observations. A theory is usually based on mathematical or logical premises that are easily acceptable. It is possible for these premises to include other Laws or theories. It usually comes in the form of "We believe (mathematically or due to lack of evidence to the contrary) that (Given Law) applies to nature because (Given premises) implies (Given intermediary reasoning/mathematics/hypotheticals) would be true and, thus, we should observe (Given Law)".
A Rule is a statement of conventions. Lubos mentioned the Right-Hand-Rule, an excellent example. Rules describes the proper way to perform a task. They usually take the form, "In order to (Given task) and be able to reconcile (task's results) with the understanding of your peers, you should (Given Rule)". A rule is unique because two completely isolated societies with the same level of scientific understanding should have the same Laws and theories, but they may have entirely different rules.
A Principle (in physics) is a statement of the limits of intrinsic natural properties. It is different from a Law because it is not a statement of one type of observation but rather a statement of the patterns governing Laws and Theories. A Principle is a powerful statement; it can never be ignored; there are absolutely no exceptions to a Principle. A Rule can be ignored easily by changing conventions. A Theory can have exceptions, which often may indicate that the theory is incomplete but they won't necessarily disprove it. A Law cannot be ignored or have exceptions within the limits established by the Principles of Nature (remember, they are statements of nature's limits). Outside of these limits, all Laws are subject to the "Law of Exceptions" - every law has exceptions, no exceptions. For example, consider the Heisenberg Uncertainty Principle. It describes the limits on the amount of information one can have about something. Within this limit, the Laws are immutable, however, if you consider (for example) distances or time scales less than the Heisenberg limit, processes that violate the Law of Conservation of Energy are allowed. It is only Principles that may never have exceptions. A Principle is usually of the form "All natural systems are subject to (Given limits) with respect to (Given intrinsic property)".
The definition I gave for a Principle might seem a bit iffy. Let me clarify, an intrinsic natural property is not a direct observable; examples are the amount of information about a system, the Action of a process, etc. To state the principle of least action in the form I identified; "All natural systems are subject to (a minimization) with respect to (the Action of that system)".
Having said all this, I realize I promised a brief answer..... It seems I failed at that. However, when explaining to someone else, it should suffice to take the first sentence of each of the 4 defining paragraphs. Hope this helps.
Comment: +1 This answer makes me angry. It feels kinda wrong when I read it, but when I think about all the different theories and Laws, they all fit this description.


GFCI breaker good, no power to outlets

Question: Drought in Texas over 2 months until last night. Now both bathroom outlets are dead. Closest outlet to gfci shows
.443 ohms on 1 set of wires. Any ideas?
I did not check continuity on outlet until I checked the breaker (which was fine) and got 120v. I tested the breaker for functionality, which was fine. I checked for voltage at the outlet and it was dead. THEN I checked for continuity and the wire from the breaker to the outlet showed .443 ohms on the white and black wires. No other continuity shown.
Comment: Measuring ohms on AC circuit wires that are not quite certainly disconnected from AC power is potentially harmful to your meter. In any case without some clarification it's unclear that whatever test you did is in any way meaningful. [Edit] to describe exactly what you did to get that reading. Perhaps the resistance from Neutral to Ground? That would be a reasonable value for that.
Comment: A good breaker shows 120 volts between the hot and neutral bar.  Does yours?  If it does then you have a loose/broken wire somewhere.
Comment: Do the "test" and "reset" buttons on the GFCI breaker operate correctly?
Comment: @Ecnerwal, not only, "*potentially* harmful to your meter," but to oneself.  NPI on *potentially*?
Comment: Crip659 - thanks, you're probably right.
Answer: Hit "test" and make sure the breaker trips.  Turn the breaker handle all the way off.  Then turn it back on.
Then, if you're comfortable sticking probes inside the panel, you should see 2 terminals on the GFCI breaker- one with a white and one with a black wire.  Grab your voltmeter and put one probe on each.  Make sure there is 120V between them.
Note that 96V, 108V or 112V is not the same as 120V, and may indicate "phantom voltage".  However if you see the same voltage as the breaker across from it to neutral bar, then it may just be low voltage at your house.
If they are showing 120V, then check the cabling between there and the first breaker.  Never forget to check neutral wires.
Comment: Yes, I did all of that and got 120v.
Comment: Yeah, you'll need to start chasing wires @Dave.

GFCI breaker good, no power to outlets


How to prevent real MAC address leakage

Question: Normally you cannot change the MAC address through network manager until after you've connected to a network and exposed your wifi card/devices real MAC address. How can I ensure that every card or usb adapter immediately gets issued a randomized or specific address the second I plug it in and never leaks the real address? I noticed that ubuntu doesn't randomize wireless network scans either.
Comment: MAC addresses to not span gateway/router boundaries. There is no such thing as MAC address leakage.
Comment: It looks like you want to ask whether Ubuntu supports something similar to Apple's "Wi-Fi privacy" function aka "MAC address randomization". If so, please edit your question to clarify this.
Answer: L3 environment
The MAC addresses visibility is limited to the broadcast domain only. It means the MAC cannot go through router to other network segments. Any network router is the OSI layer 3 (L3) device and removes any layer 2 information including the MAC in normal circumstances.
L2 environment
If you wish to hide your MAC in a local network (LAN, inside the broadcast domain), it is harder. I recommend to verify your MAC visibility by real test.
You will need a second device (PC or server, let its name is "analyzer") with installed Wireshark application and a small network switch too. I suppose the first device name is "PC1".

Connect analyzer to switch and ensure its Ethernet interface is up. No problem if analyzer has no IP address for first test. It is not necessary, only the L2 is important now.
Start Wireshark application on analyzer, select the Ethernet interface for capturing and start capturing process.
Connect the PC1 to the switch and watch Ethernet frames displayed in Wireshark. Any PC excluding very special cases will start sending some network requests like a DHCP discovery, ARP broadcasts etc. All these frames/packets have visible source MAC addresses of sending device. It can be found at the L2 (Ethernet) part of output.
Probably at least two MAC's will be visible. The second MAC is from analyzer interface. You can filter out the analyzer MAC address (and any other eventually) in Wireshark window very easy. (Go to Ethernet II --> Source. Right click to displayed MAC, in context menu select select "Apply as filter" --> "Not Selected".) Any frames having this source MAC address will be hidden. The remaining visible frames in Wireshark contain either PC1 original MAC or PC1 fake address. No other devices are connected excluding switch which has no MAC (if it is unmanaged switch).

The test done by this way will show you MAC addresses of PC1 early after cable connecting to PC. If you want to speed up the sending of the first packets, manually set the IP addresses of both devices and start ping from the analyzer towards PC1 before connecting PC1.
Wireless packet capture
It is little bit harder. The test procedure is similar like in Ethernet case, but instead of switch a wireless environment is used. You will need a Linux PC as an analyzer and a Wi-Fi card/adapter. (The Windows OS has very limited wireless capture capability excluding special Wi-Fi cards. It is not recommended for wireless analysis.)
Search for a Wireless traffic sniffing to get detail information. The Wi-Fi adapters for sniffing must support special "monitor" mode. Not all adapters have this capability. But for your purpose can be used common adapter type I think. You will capture traffic between two devices in the same wireless network. It means no special mode is required.
The same principle applies as in the Ethernet case. The analyzer must be started before the tested computer PC1 is connected to the network.
Answer: You need the macchanger package to do MAC randomization.
See here for the official guide.

How to prevent real MAC address leakage


Why are links rendering the full Sitecore content path?

Question: I'm upgrading from SXA 1.9 to 10.2 and have noticed that links on the front-end are rendering the full Sitecore content path such as /sitecore/content/tenant/site/home/path. What can I check to fix this?
Answer: This seems to be a change in a recent release of Sitecore / SXA. The fix is simple - you need to set a default language on the site definition for the site. I'm not sure if it is a SXA specific issue or a XM platform issue.
For non-SXA sites - this would be in the <site> config file.
For SXA sites - this would be on the Site Grouping item:


What is the Enterprise-E's crew complement?

Question: How many people are on board the Enterprise-E? There were over 1000 people aboard the Enterprise-D. I know the Enterprise-D was slightly bigger; would the crew complement of the Enterprise-E be a lot less?
Comment: [Memory-Beta](http://memory-beta.wikia.com/wiki/USS_Enterprise_(NCC-1701-E)) suggests about 700-800
Comment: "You look really good in that uniform."
Answer: Rob Durfee says 500
According to this site, the crew complement of the E was 500.  Although most of the information included on that page seems right, alas I can find no source to back it up, but it's the only definitive reference to a crew complement I have found so far.
Considering the Enterprise-E was refitted (because in Nemesis we suddenly have more decks by Nemesis), it is likely that this figure represents the crew complement prior to the refit.  Post-refit crew complement would likely be closer to @Overmind's answer.
Answer: According to this, on a Sovereign class the crew compliment is of 885 (130 Officers; 725 Enlisted Crew) with a limit of 2,500 person capacity.
Given that Enterprise-E, as present in Nemesis, was a refitted Sovereign, the initial value of the crew compliment may have suffered small modifications.
Comment: "Between 2375 and 2379 the Enterprise underwent a major refit. Four additional aft-facing photon torpedo tubes were added, along with one more forward-facing tube: a twin launcher aft of the bridge, a single launcher above the aft hangar deck, and a single launcher at the forward base of the bridge terracing. The bridge was refitted [...]consoles were improved across the port and starboard walls with more detailed displays. Additionally, new nacelle pylons were fitted at that time, [...], and fitted with four additional phaser arrays."  Source is Memory Alpha.
Comment: What's your source for saying it was refitted? That doesn't make much sense given that it was only the second one made.
Comment: Okay, I'm wrong. Only three years between construction being finished and a major refit. I suspect someone was stretching credulity for cool special effects.
Comment: The war with the Borg drove technological advancement in the Federation, especially military technology.  3 years between upgrades is conservative.  Video game consoles barely make it that long.


How do I take down a ufo without damaging it?

Question: I've been looking for a way to take down a UFO without doing any (or little damage) to it as possible. I haven't found any research that would help me either. My question is, is there some weapon that I can research that will act like an EMP against UFOs? It's quite difficult to get Elerium-115 in the game and I was hoping that I could just EMP or do something that can take it down without destroying all of the Elerium-115.
Answer: In original version of UFO Enemy Unknown/ Defense there is no EMPs. Best strategy to get UFO without damage is raid them when landed. You can send Skyranger, Avenger or Lightning to purse UFO but minimize the fight screen when you catch the UFO. So your ship will follow them and if landed the UFO Mission will start right away.
Using weaker fire power weapons could also help you to more likely get UFOs down without blowing up their Power Sources. This if of course against smaller UFOs. Larger UFOs still might have some intact power sources even if some of them are blown up. *Note: No resarch done, just my own intuation from years of playing*
Comment: Ufopedia refers that there is 75% change that Power Sources will explode. So it's best just trying to raid UFOs when landed.
Answer: I did a little testing by purchasing cannons and equipping one plasma beam and one cannon on each interceptor. I downed the same UFO 40 times: 10 in aggressive, 10 in standard and 10 in cautious with the plasma beam and 10 in aggressive with the cannon.
The core was never intact when I arrived at the scene. However, when I timed my arrival time 7 hours after my original testing, the core was intact each time. I think the core has a chance to be intact and that chance is rolled when you arrive at the scene.
Also I noticed the map is generated depending on the interception itself. When I approached with the aggressive and standard attack, the UFO went down in 7 shots every time, and the map was identical down to enemy placement.
However, the cautious approach downed the craft in 6 shots and generated a different map with enemies in different places. Both power sources were destroyed.
This testing was done on open Xcom with the save scumming option turned off. I will do a little more testing on variables in the future.
Answer: Like Nurkka mentioned it is not possible to crash an UFO undamaged. Personally i never noticed any relation between weapon types and damage. If you have the ability yo identify what type of ship it is you can tell if it will land in a random location (scouts), create a terror site (terror ship) or dock in an alien base (supply ship).
Always crash a supply ship or it will disappear in an alien base, you can also tell if there is a base if these ships suddenly disappear of radar.
Terror sites can yield a good amount of points so it is your choice to down a terror ship or not.
Scouts will most likely land somewhere so you could just chase them with a "crew" ship and once they land you enter the site.
Other then that, if you are after huge amount of alien supplies you can build a base fairly close to one of the alien bases. You will pickup all there supply ships and they offer tons of goodies for you.
Comment: "Always crash a supply ship or it will disappear in an alien base" that's not true. Supply ships will take a period of time before disappearing at alien bases. If you have scouted out the alien base ahead of time, its sometimes advantageous to leave it alone so you can harvest elerium and power sources from the constant stream of landing supply ships.
Comment: @z- Afaik they will hover above the base then disappear. Are you actually saying they land inside a base and you can attack just the supply ship at that time?
Comment: yes, I remember very clearly harvesting landed supply ships since that guarentees the maximum number of power sources and elerium.  This was on the PC version (non steam).
Comment: Supply ships do land. And sometimes exactly inside alien base. But then you can pick which you assault. Some tools like XCOMutil might change behaviour tho. I haven't never used those so I can't tell.
Comment: It has been a while for me too, played the original PC version as well, not even sure what version.
Answer: You could always do this the somewhat cheating method. Just save right before you get there, and keep landing. Find an instance where the ship isn't destroyed, and you'll have it.
Of course, this could take some time to identify, but it's at least worthy of thought.


Was Jacob's downward spiral motivated purely by self-preservation?

Question: In Shot Caller (2017), Jacob is sentenced to 18 months of jail time, which he and his lawyer consider "no time", when compared to the much longer 5 year sentence he might have faced, had he fought the charge in court.
He seems eager to get out so he can be with his son and family again.
Once inside, during his first night, he witnesses another new inmate get assaulted and raped in the middle of the night, and he seems so traumatised by this that he has determined nothing like that will happen to him.
So, during his first minute of recreation, he beats someone up who was hounding him, to show people he is tough, to display dominance, to demand respect - this leads him to be introduced to the white/skinhead gang, which is the beginning of the end for him, as it leads him down a spiral of crime and a lifestyle that ruins his life.
Why was he so eager to join the gang and commit all the violence? Was he merely motivated, purely, by self-preservation from other inmates' violence? Throwing your life away and putting your family at risk seems like too much of a high cost, especially for this character.
Answer: Yes, that is absolutely what it came down to.  Jacob didn't want to end up like the other inmate that was raped, and you can hear his lawyer in the voice-over telling him what it takes to get through a Maximum Security prison sentence.  After he gets into that fight, you see Frank telling him how being a "lone wolf" is dangerous, and how The Brotherhood can protect him.  If he had been in a Minimum Security prison, he would have definitely just done his time as quietly as possible to get out as soon as possible.


Is noise a random process?

Question: I have some confusion in noise signals and their nature. Can any one explain how the nature of noise signals is. Is noise a random process.
Comment: Random additions to your signal are noise, but not all noise is random.
Answer: Adding to @Kaz's answer, noise is normally modeled as a random process. Even an interfering RF carrier or hum can be modeled as a random process (random phase sinusoid).
The theory of random processes is very elegant and allows for simple analysis of systems with "noise".
Moreover, even deterministic components such as quantization or rounding errors are modeled as random processes (independent of the actual signal) in order to study system performance. And these approximations are quite good in general.
Comment: this answer cleared all my doubts..
Answer: What I've been trying to promote is a more nuanced classification system.  While it all can be classified as "noise" - i.e. an unwanted signal most noise specialists view things the following way:

Interference: Signals from other parts of the circuitry or from outside sources that are unwanted.  Best characterized by the possibility of removal through additive or subtractive methods.  Emphasis on possible.  Ultimately fixable in design or through modification.  EMI/RFI effects are one example.
Artifacts: non-linear or mixing effects in the circuit that in some cases are like case 1 , possibly removable or in some other cases behave like case 3.  Third order effects in ADC's and conversion tones and spectral splatter in ADC's are examples.
Noise: Fundamental independent noise processes that are stationary and are characterized by probability distribution functions.  Typically poisson or gaussian noise processes that follow RSS (Root sum of squares) addition (i.e. addition of energies).  Fundamentally not removable but possibly can be reduced.  Johnston, shot noise and telegraph noise.

Treating "noise" (the general term) this way allows someone to understand the possibility of abatement and analysis since mathematically they are treated very differently.
Answer: Noise is any difference between the pure signal that is desired by the engineer, and the actual signal. Well, not any difference, but a difference not related to that signal.
For example, an unwanted attenuation of some band of frequencies isn't noise, and neither is distortion.
Noise does not have to be random. An unwanted periodic signal, like power line hum or radio frequency interference, are not random, but are noise.
What is regarded as a proper signal in one circuit becomes noise if it crosses in an unwanted way into another circuit.
Your question is probably about noise generated within devices, such as Johnson noise. Such noise is random.
Comment: No, distortion most definitely *is* a form of noise, for must understandings of "noise".
Comment: When we do theoretical analysis of noise we evaluate power spectral density and analyze many related properties. So when we do analysis do we take noise as random process and do analysis.
Answer: Actually the noise is a random process which can follow different probability distributions.White noise is supposed to be having the Gaussian distribution for calculations.when you read about fading in signals which can be due to signal overlapping or distortion due to reflection the noise or the disturbance is modeled by distributions like Rayleigh or Nakagami.

Is noise a random process?


mod_ldap and mod_authnz_ldap not building for Apache httpd 2.4.4 and SVN

Question: Problem: I am trying to compile the Apache web server using the latest sources of httpd, apr and apr-util, and enabling LDAP support.  My current steps do not seem to be commpiling mod_ldap.so and mod_authnz_ldap.so.
Environment background:  Build and target OS are RHEL5.  A non-LDAP enabled instance of httpd is already on the server (2.4.1) and SVN 1.7.3 is already installed and works anonymously with httpd-2.4.1
Steps to reproduce:
Following the compilation instructions here I have downloaded:

httpd-2.4.4 in /path/apache/src/httpd-2.4.4
apr 1.4.6 in /path/apache/src/apr-1.4.6
apr-utils 1.5.2 /path/apache/src/apr-util-1.5.2
OpenLDAP and Berkley DB (for the LDAP libraries to build apr-util against) in /path/openldap-2.4.35_src and /path/db-5.3.21_src

With the sources in place, I:
compiled BDB and installed it to /path/db-5.3.21
compiled OpenLDAP using the installed BDB and installed it in /path/openldap-2.4.35
configured apr, compiled and installed it in /path/apache/apr
configured apr-util with:
./configure --with-ldap --prefix=/path/apache/apr-util-1.5.2 --with-apr=/path/apache/apr-1.4.6 --with-ldap-lib=/path/openldap-2.4.35/lib --with-ldap-include=/path/openldap-2.4.35/include
Afterwards, I built and installed with make and make install.
Finally, I configured httpd with the following:
   ./configure --prefix=/path/apache/httpd-2.4.4 --with-apr=/path/apache/apr-1.4.6 --with-apr-util=/path/apache/apr-util-1.5.2 --with-pcre=/path/apache/pcre-8.30 --with-ldap --enable-ldap

This was successful, and I was able to run make and make install
I now have a httpd instance in /path/apache/httpd-2.4.4/.  Using /path/httpd-2.4.1/httpd.conf as a model, I matched the existing configuration and loaded modules, adding:
LoadModule mod_ldap modules/mod_ldap.so
LoadModule mod_authnz_ldap modules/mod_authnz_ldap.so
However, if I run apachectl start I get a syntax error:
/path/apache/httpd-2.4.4> ./bin/apachectl start
httpd: Syntax error on line 148 of /path/apache/httpd-2.4.4/conf/httpd.conf: Can't locate API module structure 'mod_ldap' in file /path/apache/httpd-2.4.4/modules/mod_ldap.so: /path/apache/httpd-2.4.4/modules/mod_ldap.so: undefined symbol: mod_ldap
Looking within the httpd-2.4.4/modules directory, the modules mod_ldap.so and mod_authnz.ldap.so are missing.  I have tried the above steps without success.  I have discovered that within the src/httpd-2.4.4 directory, the files ./modules/aaa/.libs/mod_authnz_ldap.so and ./modules/ldap/.libs/mod_ldap.so exist, but copying those over to httpd-2.4.4/modules does not alleviate the issue.
Can someone assist me in diagnosing the error in my steps?  I know I'm missing something, but I have been unable to find it so far.  I will also add any other required information if needed.
Answer: As configured above, LDAP is supported through a shared module.  To enable the modules defined (including LDAP in my case) you need to configure apache with the --enable-so flag.  This will generate the shared modules and place them within the modules directory when compiled/installed.
Additional reference can be found in this SO article:  Compiling Apache Web Server with Dynamic Module Support


In a private blockchain network, can we delete the first N blocks and reassign the N+1th block as the genesis block?

Question: I am aware of the data loss caused by deleting the first N blocks. But I am curious to know whether such a task is possible or not. If so, how to practically implement it?
Comment: In a consensus change of a system, anything is possible if all participants agree - you simply all switch to different software. So the answer is obviously yes, but perhaps that is not what you want to know. Could you clarify why you would want to do that, or what you would hope to achieve by doing so?
Answer: With blockchains, you can basically do anything with a hard fork.  In the case of private blockchains, you will have a much easier time getting consensus for a hard fork, perhaps as easy as the authority running the blockchain dictating that everyone must accept an upgrade.
The genesis block is hard-coded into the software.  To re-assign a later block to be the new genesis block, you would need to hard-code that block into a newer version of the software.  This will only be recognized as valid by nodes running the newer version of the software.  Assuming gaining consensus isn't an issue, this is possible.
Another thing to be concerned with is block height, and all calculations based on it.  It's easy to modify the client to start counting at N+1, but this also may need to be taken into consideration when calculations are made.  This will effect things such as difficulty targets and halvings.  If you modify all relevant code to take this into account, you should be able to keep things working correctly.
Comment: Not really.  This is just an overview of what would need to be done, and I likely missed a few things.  Personally, I feel like this is a strange way to solve a problem.  My guess is that whatever problem you have could be better solved another way.
Comment: Can you specify some more things on how to do the implementation?
Comment: You also need to consider whether there's an associated data structure, like the UTXO set, which is needed to validate new blocks. If there is, that data structure will need to get to new nodes somehow, preferably by downloading it from existing nodes and checking the data against a hash distributed with the upgrade client.


Public format for 2D animations

Question: What public animation file formats are there available for 2D games? I'd like to know about both formats for procedural/skeletal animation, as well as traditional animation.
Comment: Pretty sure 2d animation doesn't really use a file format. Most 2d games use sprite sheets or similar.
Comment: Most 2D games I've worked on just wrote our own meta data to go along with those sprite sheets that gave the specific data we needed for that particular game.  Like if you have fixed sized sprites and fixed FPS then you only need the number of sprites and the individual sprite size for a given sheet.
Comment: @thedaian I'm looking for something simple to pack information about frame duration, for example, along with the actual frames, instead of having a bunch of files lying about in a folder.
Comment: As far as skeletal animation, for 2D games I've done in the past I've just used a 3D animation and rendered the game with an ortho (or near ortho) perspective.  Example of how it could be done here: http://www.thecareergamer.com/braaaains-zombieville-usa-tech-review/
Answer: I'm looking forward for the Spriter project, a 2d skeletal animation editor. I uses an XML format called SCML, here is the beta format.
Answer: I have never seen an animation file format (animation meta data, etc) that was public. I made my own from scratch. It's based on XML and I load it using tinyXML. It pretty much says where bones move to from where, at which time, over what time. Honestly not much more than that, and yet it's plenty powerful. This is for as far as skeletal goes. But for something that's not, I would go with a sprite sheet and have a meta data file about the bounds for each frame, and how many frames in total, etc.
EDIT: PS, the actual animations of my game are mostly procedural, so that data is almost all an animation file is, and then it's animated in game.
Honestly this is a question that could have lots of broad answers. But here's mine.
Comment: Yeah, there might be lots of possible answers. I used [TexturePacker](http://www.texturepacker.com/) to generate the sprite-sheet and metadata and JSON files to specify frame-duration, whether or not the animation should play in a loop etc.
Answer: There is PNG variant called MNG that supports frame-based animation. As for skeleton animations, I'm afraid you have to develop your own file format and encoder. The wise approach would be to prepare data in your games engine format, so loading skeletons would require no pre-processing.
Answer: .gif files seem to be what you are looking for. Figure out a way to decompile those and you're golden.
Comment: The problem with GIF files is that the images are limited to a 256 colour pallete. Fine if you're making a chip-style game, but not exactly ideal for a modern style.
Comment: I think GIF was originally developed by Satan. So: Noooo!

Public format for 2D animations


Showing $I=\int d^3k\int dk^0\frac{1}{k^4}$ to be logarithmically divergent

Question: Consider a momentum integral of the form $$I=\int d^3k\int dk^0\frac{1}{k^4}$$ where $k^2=(k^0)^2-(\vec{k})^2$ and the integral over $k^0$ runs from $-\infty$ to $+\infty$. This integral is common in QFT and I want to show that this integral is logarithmically divergent. The usual trick is to define $$k^0=ik^4$$ so that the integral becomes $$I=\int d^3k\int dk^4\frac{1}{\Big((k^4)^2+(\vec{k})^2\Big)^2}.$$ Now I can go to polar coordinates and do this integral. But a mapping to polar coordinate is possible if all Cartesian quantities vary in the limit $-\infty$ to $\infty$. But the integral over $k^4$ run from $-i\infty$ to $+i\infty$.
Comment: the "trick" is not to define $k^0=ik^4$; the "trick" is to Wick-rotate.
Comment: He means that the trick is not to simply change variables but to actively modify of the integration contour. This, for an analytic integrand, does not change the result.
The $i\epsilon$ prescription (that you forgot to write) makes sure that no poles are crossed when the contour is modified.
Comment: To be fair to OP, some textbooks are very unclear on this. I used to be confused why some textbooks said to Wick rotate while others said to just substitute $k^0 = i k^4$. But the latter textbooks were just saying to WIck rotate in an incredibly unclear way. For example, some just write "we perform $k \to i k$" which borders on meaningless. Any statement like "perform $X \to Y$" is just bad pedagogy.
Comment: Reinsert the epsilon in the propagators, and rotate the contour
Comment: @AccidentalFourierTransform I could not follow.
Comment: @AccidentalFourierTransform Please consider expanding your comment into an answer.
Answer: The correct definition of the integral is
$$
I = \int_{\mathbb{R}^3} d^3\mathbf{k}\int_{-\infty}^{\infty} d k^0 \,\frac{1}{(|\mathbf{k}|^2 - (k^0)^2 - i\varepsilon)^2}\,.
$$
The "$+i\varepsilon$" is the so-called $\varepsilon$ prescription which is simply giving you instructions on how to analytically continue this expression.
By this I mean that we now regard the integrand as an analytic function of $k^0$ and the integral as a contour integral on the complex plane. There are many ways of defining such a contour integral, the $i\varepsilon$ tells you which one to pick.
The reason why we choose such a prescription comes from the very definition of the propagator as a time ordered correlator, I'll elaborate on that later.
Now in an analytic function we are free to move the contour around as long as we don't cross any singularity (poles or cuts). In this case (see pictures), we can rotate the contour counter-clockwise without crossing the two poles. Since $\tilde{\infty} \equiv e^{i\theta}\infty$ are all identified as point in $\mathbb{C}$, the endpoints remain fixed.
This means that we are integrating along the imaginary axis $k^0 \in [-i\infty,i\infty]$. Now we can change variables to say $k^0 = i k^4$ and $k^4 \in [-\infty,\infty]$. The integral becomes
$$
I = \int_{\mathbb{R}^4} d^4k \,\frac{1}{\left(\sum_{i=1}^4(k^i)^2\right)^2}\,.
$$
I can drop the $i\varepsilon$ because the ambiguity is resolved. Going to spherical coordinates $\left(\sum_{i=1}^4(k^i)^2\right)^{1/2} = k$, it's easy to see that
$$
I = S_3 \int_0^\Lambda d k\,k^3 \frac{1}{k^4} \propto \log \Lambda\,.
$$
Here $S_3$ is the volume of the sphere $2\pi^2$ and $\Lambda$ a momentum cutoff regulator. The integral is actually also IR divergent, but that's because the propagator is massless. When people say that it's "log divergent," they usually talk about a UV divergent behavior.

Now, back to the why of the $\varepsilon$ prescription. In Lorentzian signature there are more than one solution to the Klein-Gordon equation
$$
(\square + m^2)\,G(x) = \delta(x)\,.
$$
Namely $G(x)$ can be a retarded, advanced, time-ordered correlator, etc... The propagator is the time ordered correlator by definition
$$
\langle 0 | \mathrm{T} \phi(x) \phi(0) | 0 \rangle\,.
$$
The time ordered correlator can be written with the aid of the Heaviside $\Theta$ functions $\Theta(x) = \max\{x,0\}/x$, which can be represented as
$$
\Theta(x) = \frac{1}{2\pi i}\int_{-\infty}^{\infty}dt\,\frac{1}{t-i\varepsilon}e^{ixt}.
$$
Then one can explicitly compute the correlator by inserting a complete set of states
$$
\mathbb{1} = \int_{\mathbb{R^3}} \frac{d^3 \mathbf{k}}{(2\pi)^3} \frac{1}{2E_{\mathbf{k}}} | \mathbf{k} \rangle\langle  \mathbf{k} |\,,\qquad E_{\mathbf{k}}\equiv\sqrt{|\mathbf{k}|^2+m^2}\,,
$$
and using $\langle 0 |\phi(x) | \mathbf{k} \rangle =e^{i \mathbf{k}\cdot \mathbf{x} - i E_{\mathbf{k}}x^0}$.
I'll not go through the details because this is covered in most textbooks. For example $[1]$. Bottom line: if you compute the correlator carefully, the $\varepsilon$ prescription shows up naturally.
There is an alternate way to think about it. Note that in Euclidean signature there is only one correlator (since there is only one solution to the Klein-Gordon equation above), and it is the one with Eclidean-time ordering. This can be seen by inserting a set of energy eigenstantes
$$
\langle \phi(x) \phi(y)\rangle_E = \sum_n \langle 0 |\phi(\mathbf{x},0) | n \rangle\,e^{-E_n (x^4 - y^4)}\,\langle n | \phi(\mathbf{y},0)|0\rangle\,.
$$
Since the energies are unbounded from above, one must have $\Re(x^4 - y^4) > 0$, otherwise this sum explodes.
The way in which we define Lorentzian QFT is by analytic continuation from Euclidean, where things are better defined (in the path integral formulation for example). This means that the Lorentzian propagator is the analytic continuation of the Euclidean one. As I showed in the pictures, the contour can be continuously deformed only if the poles are put in that way.

$\;[1]\;\;$  Michael E. Peskin, Dan V. Schroeder, Frontiers in Physics, An introduction to quantum field theory.
Comment: I think I understand it now. Thank you for the help.
Comment: I think there should be two minor edits, but will let OP confirm. The second and third equations are missing a factor of $i$ on the RHS. The first equation defines capital $I$ is imaginary; you can see this by the fact that taking the complex conjugate reflects the pole locations across the real access and so the Wick rotated path of the complex conjugate runs down the imaginary access rather than up (cf. pictures in OP answer). The second and third RHSes are explicitly real, but they should be explicitly imaginary (hence the factor of $i$ (from the change of variable from k0 to ik4)).
Comment: I agree, I missed an $i$ in the change of variables. If you figured out the $i$'s correctly feel free to edit.


How do electrons flow in an inductor

Question: This may be a very simple question. But if I have a coil of copper wire, why don't the electrons just take the shortest path vertically through the coil instead of following the entire loop around?
Comment: The copper wire of which the coil is made has a coating made of an insulator.
Comment: If you downvote a question, please come with a reason to why, so that I can improve in the future. "Dumb question" is not a reason to downvote.
Comment: This is a perfectly good question that has a simple answer. I can only assume people are downvoting because the answer is obvious to them, but it's quite reasonable that someone new to electronics might not realise enamelled wire is a thing. After all, it often looks nearly identical to bare copper wire.
Comment: Thanks, and true. That was my thoughts exactly. For me, until this question was answered, a coil of copper seemed like pure copper wire without coating, and thus the whole thing appeared to be a little arcane.
Answer: The wire from which an inductor is wound is coated with an insulator so the current can only flow along the wire and not sideways between two parallel strands of wire.
If you used uninsulated copper wire then you would in effect end up with a copper cylinder, and you are correct that the current would just flow along the cylinder and not around it.

How do electrons flow in an inductor


Did France send people from other countries to fight first during WWII?

Question: I am from Poland. This past weekend, I talked with my mother-in-law, who was born in 1935 in France. In 1939, right before World War II broke out, she and her family went back to Poland. I was shocked and asked why they did it. Weren't they aware that Germany could attack Poland? She answered that they were guessing that it may happen but, in case it did happen, they wanted to be eventually on the Polish side. Moreover, she said that her father's brother stayed in France and, when Germany attacked France, he had to fight on the first front. Is it true that France first used people from other countries to fight before starting to use French people?
Comment: It's not like the French chose where the Germans attacked…
Comment: @JonCuster between the start of the War and the start of the invasion of France there were 8 months. Besides the side-show of Norway, there was little activity during this time.
Comment: France had colonial troops, but those were only a fraction of the troops on the front. Other than that, I do not know what your mother in law was talking about, maybe you should ask her about the nationalities of those troops. And France was mostly in a defensive stance, so they "did not send them to fight first" because they basically did not send anyone to fight (they did recruit troops but kept them at defensive lines).
Comment: *when Germany attacked France then he had to fight on first front* Are you asking whether when Germany attacked France in May 1940, France "first used people from other countries to fight before starting to use French people?"
Comment: And of course, https://www.youtube.com/watch?v=AQnEBSwdAXw
Comment: @user103496, yes, that was what I meant, sorry for not clear english
Answer: No, not true.
France had conscription. In case of war the army would be placed on alert and war footing, meaning that draftees were recalled to the army. Foreigners cannot be drafted. I know of no nation that drafts foreigners. That's technically next to impossible: which foreigners? Tourists? Expats? How well do they need to speak or understand French? (Foreigners who volunteer is an entirely different topic.)
Your mother may be mistaken by the French Foreign Legion. The Foreign legion recruits foreigners exclusively. Frenchmen can enlist, but must do so under a different name and nationality to serve in the ranks. All officers are French. Nearly all non commissioned officers are promoted from the ranks.
It is true that the Foreign Legion was founded to save spilling of French blood. A legionnaire who gets seriously wounded in action gets French nationality immediate. Otherwise, he can become French citizen after 3 years of service. The legion was specifically set up to save French lives in colonial campaigns, but they also fought in France itself during WW1 and WW2.
A little side note: the Dutch East Indian Army KNIL was set up for exactly the same reason: to save, in this case, Dutch lives by recruiting foreigners to do the job. The KNIL was trained in The Netherlands, but never fought there.
It's very likely your mother talked about the Polish army in France, who were refugees from Poland after the occupation by the Germans in 1939. Those were volunteers, the unit was not (as the Foreign Legion was) set up to save French blood.
Comment: Re " I know of no nation that drafts foreigners." The US requires almost all males age 18-25 who *live* in the country to *register* for the draft: https://www.usa.gov/register-selective-service . No draft has been in effect since 1973, but as I understand it, if the draft were ever re-instated, all those registered *could* be drafted (specifics presumably would be TBD, so it is unclear what would actually happen in the case of foreign nationals).
Comment: Another possibility is that her uncle had been naturalized. This is how (e.g.) [Wolfgang Döblin](https://en.wikipedia.org/wiki/Wolfgang_Doeblin) ended up in the French army.
Comment: [History of the French Foreign Legion](https://en.wikipedia.org/wiki/History_of_the_French_Foreign_Legion#Second_World_War) outlines that 6 regiments of FFL were deployed variously at the Somme, Soissons, Verdun, Alsace Maginot Line defenses, and Nancy in May 1940. In other words, they were distributed to multiple French and across virtually the entire front.
Answer: Another event that could be simplified into this idea was the deployment of French colonial troops in the early stages of WWII (and WWI). France had a significant army in Algeria from 1830 until 1962, which contained large numbers of Algerians.
At the start of each war, troops from Algeria were shipped to France. This made perfectly good sense: France was threatened, and the units that were sent there were already in active service. That meant they could be ready to fight in France more quickly than French reservists could be called up, formed into units and got ready for action.
Comment: Seeing that coastal Algeria became part of France in 1848 ([Wikipedia](https://en.wikipedia.org/wiki/French_Algeria): "Algeria was a part of France from 4 November 1848 when the Constitution of French Second Republic took effect until its independence on 5 July 1962"), Algerian troops serving in the armed forces of France during both WWs would not be "people from other countries" in a legal sense.
Answer: World War II and World War I are two separate conflicts that occurred at different times. France was involved in both wars, but I'll provide some clarification:

World War I (1914-1918):
France was one of the major Allied powers during World War I. They did not send people from other countries to fight in World War I; instead, France and its allies had their own armies and conscripted soldiers to fight in the war. Many soldiers from France's overseas colonies, such as Algeria and Senegal, also served in the French military during WWI.

World War II (1939-1945):
In World War II, France was one of the early victims of the war when Germany invaded in 1940. After the fall of France, the Free French Forces, led by General Charles de Gaulle, were established. These forces included French troops who had managed to escape the German occupation and continued to fight alongside the Allies. France also had colonial troops and units from its overseas territories who contributed to the war effort.

So, in World War I, France did not send people from other countries to fight, but in World War II, they had a diverse set of forces fighting for the Free French and also had colonial troops and units from their overseas territories involved in the conflict.
Comment: Please note there is a site policy against the posting of AI generated content here.
Comment: Not sure what WWI has to do with the question.  The section on WWII is assertions without evidence. Please revise.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


TV studio set reverbation treatment?

Question: Hi all, I currently work on a TV project (sitcom), which is being shooted in big TV studio. They built some family house rooms there. But basically the studio is very big - 20m width, 60m length, 15m height and rooms don't have any ceiling (of course - due to lighting) and they don't have one or two walls either.
As you can imagine there is a lot of reverbation on the dialog, which is more than inadequate to what you see on TV later.
Do you have some skills with treating this reverb in similar location?
I was thinking of placing some rock wool material there, but cannot imagine how much and where to put them for such a big space.
Thanks for any ideas ;-)
Sorry for my english :-O
Answer: There exist acoustic sails you can install/ hang from the ceiling. so light comes through.
You can use some molton fabric to make some kind of walls.
Just put them on special sliders etc. like you put your curtains on. So you can move the fabric to every
shooting position/ direction.
If not possible to install just use tripods/ stands with crokos from the lighting department to "narrow" the room.
Use carpets or molton as carpets.
another idea ist to build things like this:
http://realtraps.com/p_gobo.htm
But for the insulation don´t buy rockwool-
it´s to itching when a lot of air movement occurs.
Use basotect instead.
Or hemp wool :-)
Answer: Use lapels? Or in post, use Waves RVox plugin (sometimes it's too clean and missing a human quality), but be sure to keep all movements in separate tracks. Können wir auf Deutsch sprechen?
Comment: Thanks, but I need to find out some acoustical solution for entire space. I use lapels of course, but it's not so good as a boom mike. And one more problem - to clean lapels tracks and match them with the phase of boom tracks takes time which I don't have, is a very fast production model - sitcom. PS: I don't speak German, sorry :(
Answer: How about this plugin http://www.youtube.com/watch?v=yitJOeFkscc&sns=em

TV studio set reverbation treatment?


What does pre/post modification mean in Airbus MPD?

Question: What is the difference between POST MOD (with partial mod i.e SXXXX) and PRE MOD (with partial mod) in the applicability column of an Airbus MPD (Maintenance Planning Document)?
Answer: It means that operator have to check what status of the particular MOD have the subject A/C, pre or post. Therefore it affects operators MP.
Answer: "Post Mod" means the modification issued by the manufacturer was carried out on an aircraft, and "Pre Modification" has the opposite meaning.


Sort an array of sentences alphabetically, ignoring the first word if it equals 'the' (case insensitive)

Question: function order_ignore_the($a, $b){
     // orders sentences ascending alphabetically, ignoring the  work "the"
     $args = func_get_args();
     foreach($args as $k=>$v){

          $sort = explode(" ",$v);
          $args[$k] = (strtolower($sort[0]) == "the" ? $sort[1] : $sort[0]);
     }

    return strcmp($args[0], $args[1]);
}

usort($array_of_sentences,'order_ignore_the');

Answer: With some testing, it should look like the below
function order_ignore_the($a, $b) {
    return strcasecmp(
        strcasecmp(substr($a, 0, 4), "the ") != 0 ? $a : substr($a, 4),
        strcasecmp(substr($b, 0, 4), "the ") != 0 ? $b : substr($b, 4)
    );
}

Main differences being:

Widening the search for "the" to include the space after. Otherwise, you're matching on things like "theater", etc.
The last substr should likewise have start position 4. Otherwise, you're comparing on the space after "the".
You'll want the main comparison to ignore capitalization, too.
Answer: I'm not sure what you're doing there, but I think it can get shortened to this.
function order_ignore_the($a, $b) {
    return strcmp(
        strcasecmp(substr($a, 0, 3), "the") != 0 ? $a : substr($a, 3),
        strcasecmp(substr($b, 0, 3), "the") != 0 ? $b : substr($b, 3)
    );
}

Be warned that this is not tested.
Edit: Long version with explanation:
function order_ignore_the($a, $b) {
    // Variables for later use
    $checkedA = $a;
    $checkedB = $b;

    // Compare the first three letters case-insensitive against "the"
    if(strcasecmp(substr($checkedA, 0, 3), "the") == 0) {
        // strip the "the" from the string
        $checkedA = substr($checkedA, 3);
    }
    // Repeate for $b
    if(strcasecmp(substr($checkedB, 0, 3), "the") == 0) {
        $checkedB = substr($checkedB, 3);
    }

    // Compare both strings
    return strcmp($checkedA, $checkedB);
}

Yes, it's swapped, I'm checking in the short version if the string does not match "the", and here I'm checking if it does match.
Answer: I took a moment to compile a list of real movie titles which represent some squirrelly fringe cases.
I arrived at a one-liner that relies on regex for best accuracy that doesn't fail when the leading The word is not immediately followed by a space.  Notice that one real movie title below starts with the word "the", but the fourth character is not a space, so your exploding technique will not accurately remove it.
Your custom function explodes on spaces and assumes that all titles will contain at least one space -- this is a falsehood.  Your code will generate Warning: Undefined array key 1 errors every time it encounters a movie without a space.
Another problem with your use of explode() is that you are not limiting the generated output to 2 elements.  This will lead to incorrect results when comparing The Matrix, The Matrix 2, and The Matrix 3. Effectively, the The words will be stored as [0], then the word Matrix as [1], and any/all subsequent characters in the title are doomed to go unused.
Note, because you are using func_get_args() in your custom function and you never reference $a or $b, you don't actually need to declare them as arguments for your script to run.
Effectively, the preg_replace() call trims off the qualifying The in the temporary array which is only used for sorting the original array.
While regex is generally a more expensive technique than non-regex techniques, it never revisits any values because it is not called within the sorting iterations.
This snippet will deliver a much more accurate sort than the code you have posted.
Code: (Demo)
$array = [
   'The Theory of Everything',
   'The Mummy Returns',
   'The Mummy',
   'Then Came You',
   'The One',
   'The',
   'The 100',
   'The Matrix',
   'Theft',
   'The...',
   '300',
   'The 300 Spartans',
   'Mad Max',
   'Then',
   'The Martian',
];

array_multisort(preg_replace('/^the\b ?/i', '', $array), $array);
var_export($array);

Output:
array (
  0 => 'The',
  1 => 'The...',
  2 => 'The 100',
  3 => '300',
  4 => 'The 300 Spartans',
  5 => 'Mad Max',
  6 => 'The Martian',
  7 => 'The Matrix',
  8 => 'The Mummy',
  9 => 'The Mummy Returns',
  10 => 'The One',
  11 => 'Theft',
  12 => 'Then',
  13 => 'Then Came You',
  14 => 'The Theory of Everything',
)

Comment: I must have gotten stuck in my own head about using movie titles instead of "sentences". Sample data in the question would have helped me.  Anyhow, my guidance still sings true.


Intersection of conics

Question: By conic we understand a conic on the projective plane $\mathbb{P}_2=\mathbb{P}(V)$, where $V$ is $3$-dimensional. I'd like to ask how to find the number of points in the intersection of two given smooth conics $Q_1$ and $Q_2$ (given by $q_1,q_2\in S^2V^*$ respectively). So, we are to find the set of all $(x_0,x_1,x_2)\in V$ such that $q_1(x_0,x_1,x_2)=q_2(x_0,x_1,x_2)=0$. First, is this number necessarily finite? And second, how to describe such intersection of quadrics (i.e. 'conics' in $\mathbb{P}^n$) in higher dimensions?
I'm sorry for the lack of my 'research', I'm really stuck on this problem.
Comment: Search for "Bezout's theorem". Short answer for distinct smooth conics in the plane: the number is finite --- indeed, at most 4.
Answer:
First, is this number necessarily finite?

No: a degenerate conic factors into two lines. Two such degenerate conics might have a line in common. This line would be a continuum of intersections. Barring such a common component, the number of intersections is limited to four.

And second, how to describe such intersection of quadrics (i.e. 'conics' in $\mathbb P^n$) in higher dimensions?

If you want to count them, then Bézout's Theorem, as mentioned in a comment, is indeed the way to go. Wikipedia includes a generalization to higher dimensoons. Applied to quadrics, you get the result that barring shared components, $n$ quadrics intersect in up to $2^n$ points. In exactly $2^n$ if you include complex points of intersection and take multiplicities into account.
Comment: Nitpick of your first answer: the OP did say two _smooth_ conics.

Intersection of conics