How do I remove exchange from SBS 2011 and continue all other SBS functionality?

Question: I recently moved my client to Office 365 from SBS 2011. All is stable now.  They wish to continue using all the other functions of SBS i.e. Remote Web Workspace, SharePoint Calendars, TS Gateway. Should I and how do I remove Exchange from the SBS server? I currently have stopped al the services related to Exchange, and moved the mail store to archive.  Will it break anything else to remove the Exchange?  Several posts on this board refer to " remove Exchange from your SBS 2011 environment" without a hint of how, and most go on to either Migration of AD or decommission the server.  I wish SBS to continue as AD server. I see the Exchange in "Add & Remove Programs" could it be that easy?  And again will it break anything.
Answer: No, don't remove Exchange from SBS 2011, it's not supported, it WILL break things and there's absolutely no point in doing it.
Comment: I expected as much, but could not find a definitive answer.  Thanks for the advice.
Answer: Stop & Disable all Exchange Service, as you will end up with problem if the uninstall is done incorrectly.
A example for SBS 2008; https://technet.microsoft.com/en-us/library/dd728003(WS.10).aspx, and please take note that those steps seem to not had been wrote for SBS 2011, so is it supported ?


C# .NET - How do I load a file into a DataSet?

Question: I need to load a file (usually ASCII) into a DataSet. How can I do that?
What data types should I use for my columns?
Thanks.
Answer: you can use byte[] for the type,
Maybe a DataTable like this can be useful for you
DataTable dt = new DataTable("files");
dt.Columns.Add("name", typeof(string));
dt.Columns.Add("size", typeof(int));
dt.Columns.Add("content", typeof(byte[]));

Answer: Not sure if this is what you are looking for but you can find a sample here:
Fill a DataSet from delimited text files
Answer: DataSet is one huge typeless hole, it should be the least of your worries.
Add some reflection for more fragility and you should be there within seconds.. It also ends up with plenty of casts.
Again bad design, columns can be anything and as such you can add or retrieve any type any way you or they want it and your syntax will be damaged. You get no compile-time safety, simple.
Better type your data and then pass the typeless dust to DataSet via an extension method.. XML kids do the same for XML files (which is just as nuts).


Reconfigure Samsung Galaxy Note 4 Fingerprint Scanner

Question: Is there a way to avoid clicking on the centre button where the fingerprint scanner is. I would like to reconfigure the fingerprint scanner to go to home when brushed. Is that possible?
Answer: Not without rooting the phone, no.
Comment: That means, the answer is actually, "Yes, if you're rooted". Meanwhile, could you provide the steps/reference to do this on rooted device?
Comment: And any apps that do that when rooted? Am I the only one annoyed (and lazy) by the clicking
Comment: No, my wording was precise. Without root it's not possible. With root it MAY be possible, but I'm unable to locate any appropriate apps to do so, and I suspect it's not. In reality, I don't believe there are any capacitive sensors in that button, so without pressing it, it's unaware that you're interacting with it.


Does alacrity affect GCD in swtor?

Question: Does the alactrity or "activation speed" stat decrease GCD in swtor?
Answer: No, the global cool down is not effected, except in the case of cast-time abilities.
Source: http://sithwarrior.com/forums/Thread-Alacrity-and-the-GCD
Answer: Yes. As of game update 2.0 Alacrity was improved. It now affects resource regeneration and the global cooldown.
Source: http://www.swtor.com/info/news/blog/20130417-0
And as of game update 3.0 alacrity also affects over-time effects and everything else. A character with 10% alacrity should be 10% faster in everything.
Comment: Note also that as of 3.0, Alacrity affects *everything*.  Tick speed of your DoTs, internal (proc) cooldowns, ability cooldowns, etc.

Does alacrity affect GCD in swtor?


Anode and cathode in electrolysis

Question: Can the anode and cathode in electrolysis be the same material and still separate out the oxygen and the hydrogen? I could not find any information about if platinum makes a good cathode or anode, some sites said it was good for an anode, and other sites said it was good as a cathode.
Comment: Electrolysis of water using platinum electrodes..
Comment: @safdar, we don't have to be too rigid. It is clear that the OP did search websites. It is question based on a confusion. Why can't one reply in line, that potentially any inert conductor can work. It is certainly not a textbook or homework question.
Comment: @M.Farooq, that was just an auto comment. The fact is OP saw it can be good anode, good cathode but didn't think to piece them together. Also,  electrolysis of water is a very common electrolysis where the electrodes used are either graphite or platinum which is talked about in many cases. I replied with an example within 2 minutes and then waited for 30 mins before sending that comment
Comment: Any conductor can potentially serve as a cathode or an anode.
Comment: Water cannot be electroyzed alone. To electrolyze water, an electrolyte has to be added to water. The electrolyte can be an acid, a hydroxide or a salt. The electrode can be any sort of metal, provided it does not react with the electrolyte, and is not easily oxidized at the anode. Platinum does not react with usual electrolytes, and is not easily oxidized at the anode. So platinum is usually chosen for anodes and cathodes : it is convenient for both.
Answer: A good electrode for electrolysis is:

An electrical conductor.
Chemically stable in water and in oxydizing environment of the anode / reducing environment of the cathode.

Most metals are OK being cathode in electrolysis as they fulfill both conditions. Well, sodium and friends are not good - it is not stable in water in the first place. Some non-metal substances are also acceptable - e.g. graphite. Even metals that are somewhat unstable in water (e.g. iron) are stabilized when used as a cathode and the effect is sometimes used as a corrosion protection.
Anode is the harder task. A lot of metals that are more or less stable in water oxydize when used as anode and will not last long. They will also "eat" some electrical charge and you'll get less than expected oxygen (you may as well get none). Precious metals are OK, graphite in lower temperatures is OK, too. Some metals use a trick: nickel or lead (and some other metals) anode (in proper conditions) forms a thin oxide layer that is itself (somewhat) conductive and also stable in regard to further oxidation.
Answer: As a cathode is usable near any conductor, which does not dissolve in electrolyte.
Anodic material must withstand aggressive anodic oxidative processes without dissolving. Aside of platinum, glassy carbon is often used. Questionable can be stainless steel.
Electrodes should not  be vulnerable to desintegration by evolving gases. E.g. otherwise inert but porous carbon electrode from zinc cells ( my first attempt as a young chemist ) forms fine carbon dust during electrolysis.

Anode and cathode in electrolysis


Manhwa where the female lead is executed by her family and sent back in time by the male lead, who is a wizard

Question: I read this manhwa a few months ago but forgot its name, where the female lead was executed by her family (I don't remember why) and gets sent back in time by the male lead who is a wizard, but he can't remember why he sent her back.
More detail is that the female lead has black hair and the male lead has yellow hair.
Comment: Where are you likely to have read it?
Comment: Did the female lead have a blonde sister? Was she executed because she wasn't able to learn the family magic, but the sister could?
Comment: Oh yes I forgot that part I think she was also abused of being a fake? Because she couldn't use magic
Answer: This is I Am the Real One, also identified here. It is licensed by Tapas.

A prophecy foretold that the Grand Duke would only have one water elementalist born from him. Though she lacks her father's affection, Keira knows she's destined for those powers. But after years of doing what was right and proper of a noble, she's executed after the conniving Cosette appears, claiming to be the Grand Duke's real daughter. But then—Keira wakes up with newfound purpose: make changes, allies, and even friends before it's too late. Will it be enough before Cosette hatches her plot?

Due to a prophecy that her father will only give birth to a single elementalist, the protagonist is assumed to be a fake after her half sister suddenly appears and demonstrates elemental powers. This results in her executed for being a witch, but she wakes up in the past and resolves to change her future.
The scene with the mage is in chapter 32, plus a bit of the end of 31. The blonde magician realizes that she has gone back in time through his magic, but has no idea why his future self did it.
Comment: Another match; https://scifi.stackexchange.com/questions/266052


Error: ERR_TOO_MANY_REDIRECTS while loading Lightning App

Question: I'm getting ERR_TOO_MANY_REDIRECTS error in browser console while opening the lightning app. This doesn't affect the functionality though, it is making delay in loading completion of the app. I'm making one call to Apex class to populate records through "Init". Any suggestions to improve loading time or any idea about what this error is about? Thanks in advance!
Comment: No known "growing pains" like this currently being tracked. Vignex can you provide a repro case with specific instructions - what you have provided so far is insufficient info for me to act on.
Comment: When you say "opening the lightning app", you mean you are going to your custom app's URL? (EX: myorg/myapp.app) Or is this a tab in the Salesforce1 app? Is there anything else in the browser console? My suspicion is this may be some beta growing pains.
Comment: @Peter. It is going to the app through URL. I'm getting this error twice during the navigation to the app URL.
Comment: what instance are you on?
Comment: Can you show us your init code?
Answer: The last time that I encountered this was when there was a stored site setting in my chrome browser. After clearing the site setting and allowing third party cookies in chrome, this cleared right up. The issue is that the stored setting stored an old session token in a cookie that had since changed. So what it was doing was attempting to acquire a new one and Chrome was persisting the cookie and blocking the new values. My settings now look like this:

After this change, I have never seen this again. I regularly log in to at least 8 different instances a day and each one loads very fast without issue.
Answer: I've encountered this problem today while using chrome (v.43.0.2357.130 m) while trying out the Trailhead tutorials on lightning components. I managed to workaround it by using a different browser, or by starting a new browser session in chrome (e.g. forcing incognito mode and logging in again). Hope this helps somebody with the same issue in the future.
Answer: I've seen this a few times. I can think of 2 things:

It's possible you have circular reference in your client-side code somewhere.
I would suggest looking at the Debug Console and seeing what APEX code
is actually being executed to make sure that it's really only
running once, and that it's not causing some error.
Answer: I have faced this issue too, I needed to set up a domain (for eg; your name.instance.salesforce.com) and if that doesn't work you should also try to run it in incognito as @topealvim mentioned!
Answer: I found that I could fix the issue I was having with Conga (different app same error message) via salesforce settings
In the setup menu > security >  Session Setting
Update the following

Adding the visual force page to the Trusted Domains
and by also checking "Enable XSS protection" checkbox on that page

(just make sure to hit save on the bottom of the page)


Do we need a model for dynamics of IR to price a vanila swap?

Question: This question has been asked in several different forms, and the answer given seems to be always "no" because we can "simply read off the yield curve". However, since the yield curve (or "a yield curve" in a multi-curve world) is constructed from various market instruments (e.g. futures), do we not need a model for rates to derive the yield curve from these instrument (to, for example, calculate a convexity adjustment to be applied to futures)? SO, the question is, given prices of market-observables instruments. do we need a model for dynamics of rates to price a vanilla IR swap?
Comment: I think for plain old vanilla swaps you just need a nice interpolation at most rather than dynamics, unless it's in arrears (or CMS obviously) - happy to stand corrected!
Answer: The answer is that it depends of the Zero Curve you're looking to build and the precision and maturity of it. For example, for the Libor3M curve, you might need indeed to use futures if you want to obtain a clean smooth curve for maturites close to 1Y. But again, if you're planing on using longer contracts, you can just bootstrap that part of the curve. It depends the level of precision you're looking for respect to the market.
Most of the time, curves are built different from each other, so you just need to understand the Index you're trading. So the answer would be, yes we need a model for dynamics of rates, as long as the index underlying the swap has the instruments to obtain such data. Otherwise, you won't be marking to market.
Comment: And if there are no instruments for the underlying index, then what? How does one calculate the floating leg payments in that case?
Comment: Well, how are you going to have a floating leg with no underlying index? You need something to link it to.
Comment: That was your statement, wasn't it? Quote: "[...] as long as the index underlying the swap has the instruments to obtain such data". That's why I asked my question in the previous comment. Or did I misunderstand what you meant by that statement in your answer? Thanks
Comment: It would be difficult to trade a swap with no underlying swap curve but in those cases it depends. Most of the time banks will structure the derivative but you won't be able to see for yourself how much spread you're getting. No exact formula for that type of swap.


DWR like Javascript library for REST

Question: Is there a Javascript library like DWR that can generate javascript stub for REST api. We are using Jersey/JSR-311 for REST on server and was wondering that instead of using libraries like Jquery or dojo if there is a library that can take a Rest class annotated using JSR311 annotations and create javascript stub like DWR does?
Answer: This seems like one of the big benefits of RESTEasy over Jersey.  See http://docs.jboss.org/resteasy/docs/2.0.0.GA/userguide/html/AJAX_Client.html for more info.
I don't know whether the functionality works on Jersey or not.
What I'd like to see: Generated API test pages for REST and SOAP pages, like .NET has.
Answer: I am about to commit such a thing for RESTEasy, the JBoss implementation of JAX-RS. You can expect it within a month. It might even become portable and work for Jersey if there is traction.

DWR like Javascript library for REST


GETH + web3.js Max Transaction Fee

Question: There is a built-in default max transaction fee of 1 ETH with my GETH node + web3.js library.  Where can I change that?  I cannot find the option anywhere...
Answer: If you're connecting over RPC, you're limited to 1 ETH by default unless you include this flag when you start geth:
--rpc.txfeecap value  where value is the amount in ether.
[Reference: https://geth.ethereum.org/docs/interface/command-line-options]
Comment: Thanks.  I'm assuming the transaction fee is calculated with the gas limit and not the actual gas ?
Comment: That's correct : your local node can only estimate the cost of the transaction based on the state of the chain it sees. The actual gas could end up being different if the state changes before your transaction gets mined.

GETH + web3.js Max Transaction Fee


How can one rule out the possibility of there being neutral quarks?

Question: This is a very simple question, which will most likely yield a prompt response from someone who knows more than I. The reason I ask:The quarks that we can detect (as they interact electromagnetically) are much lighter than the particles that they make up. From what I know, we say that gluons augment the energy level of the quarks when they combine to form baryons, yet if there are quarks that are made up of partial charges, how can we rule out the possibility of another type of quark made up of partial neutrals(or just a uniform neutral quark)(?). One could say that neutral doesn't exist, and it is merely a combination of partial charges that sum to zero. Yet neutrinos exist as leptons, which are independent of quarks. Is it possible that there is a relationship between the gluon, gauge bosons, and lepton pairs that all has to do with the instant something such as a beta decay occurs subsequent to an ephemeral appearance by a W boson? And that they would all turn out to be the same thing just for the instant the gauge boson acts as a mediator?
Answer: Neutral quarks can be excluded experimentally (up to a certain mass), because the neutrinos match the invisible decays of Z bosons perfectly. If there were neutral quarks below half the Z mass, the Z boson should also decay into these.
For higher masses, things get more involved. Finding out that you're not seeing something going on is hard, but our experimental physicists can do just that. And they don't see any "invisible" particles.
Finally, neutral quarks would also affect the running of the strong coupling which is measured to good precision. New quarks, i.e. new color charged particles, would change the rate at which the strong interaction becomes weaker with higher energies (it would become weaker even more quickly). Again, calculations using particles from the Standard Model match the observation excuisitely, just like for the invisible Z dacays.
Comment: In addition the baryons and mesons observed fit in mutliplets that cannot contain neutral quarks. There has not been an observation where a baryon or meson  resonance would not fit in a weak SU(3) multiplet. Observing such discrepancies  would have forced us to look at the possibility of neutral quarks.
Comment: Thank you for that in depth response. Well thought out , well relayed. I understand the topic fully, and possess the capacity to explain this to others who have similar questions. That is priceless.


Google Analytics showing page views from pages I don't have on my server?

Question: What does this mean? I don't have these pages/directories but GA is showing them as pages viewed. I tried to follow the link and I didn't make much sense out of it.
Comment: We can only guess. You might need to contact Google support. It is also possible that your site has been taken over and the attackers are creating and dropping pages.
Answer: If you display a generic 404 page for those URLs, then Google Analytics may count it as a "page".
With those pages, someone may be attempting to see if you're a proxy, or if your site can be used to redirect users. It's noise traffic that comes from scripts and bots. Unless you have a vulnerability on your site, it's really nothing to worry about.
Answer: One possibility is as Ohnana said.
Another is that there are bots that send traffic data directly to Google Analytics server. These also may show as results. Sadly there's nothing you can do to stop them since they bypass your webpage completely. Here's a link1 about the issue.


Why is this overdefined? Can't I move right vertical line to the rright?

Question: Why is this overdefined? Can't I translate eveything yellow horizontally to the right?
Comment: There is a coincident constraint at the bottom. So, I don't think you could move the whole thing to the right as you said. I think the 20.75 is the one causing the problem (both this and the coincident constraint are related to the same lines.
Comment: At the very bottom right of the sketch window there's a button you can click where solidworks will automatically remove one constraint at a time until it is able to solve, and presents you with the options it finds.
Comment: The coincident constraint here is also likely one of the reasons you can't delete the object below - couldn't see from the other question.
Answer: The coincident relation at the bottom of the line on the right will prevent you from moving it horizontally. It is overdefined because your 20.75 dimension is probably too short or too long to reach the corner that the right-hand yellow line is coincident too. Your line is also vertical, meaning that it cannot move only the upper point of the yellow line to satisfy the dimension.
Hope this helps!


Time - Does the Big Crunch mean our existence would be cyclical?

Question: Given Nietzsche's Eternal Return philosophy, would the Big Crunch mean that our existence is cyclical, and therefore coincide with Eternal Return philosophy?
Comment: Note that the Big Crunch is a scientific theory, and recent discoveries have strongly favored the Big Rip from expansion of space, which would ensure that the Universe doesn't repeat itself.
Comment: total lack of effort
Comment: **No** -- even if we assume that existence is cyclical, that is not sufficent for ***our*** existence to be cyclical.
Comment: At some point in the Big Crunch, Heisenberg's Principle should exert so much power that the next instance is unrelated to the previous one.  Each iteration should originate with a basically random and therefore almost always different starting energy, which determines the course of the rest of the iteration.  Things should never repeat.
Comment: @DavidThornley No, the Big Crunch is a scientific *hypothesis*.
Answer:
What, if some day or night a demon were to steal after you into your loneliest loneliness and say to you: 'This life as you now live it and have lived it, you will have to live once more and innumerable times more' ...

That, combined with a closed universe collapsing--how does it measure up? It doesn't. They are two unrelated ideas. One is more about philosophical implications, and the other about modern cosmology.
For both to be reconciled, there would have to be a perfect mechanistic materialist resurrection occurring. Although, even that is different from what Nietzsche was poking at. He did not mean one iteration of history, of our lives, continually reoccurring. He meant that given infinite possibilities, forever, every possible iteration would have to repeat itself. [Correct me if I'm wrong, but that is how I interpreted the text.] Since this life you are living now is one of such iterations, it is bound to repeat. That is the opposite of the Big Crunch.
Think of it as gas filled balloon (your life, the universe). Will it pop or be blown up the same way every time? Or superheat a rock; condense it down to magma. Then, will it expand the same way every time once cooled?

Here is a long discussion: thephilosophyforum.com/discussion/410/musings-on-the-nietzschean-concept-of-eternal-recurrence
Comment: If there's an infinite number of Big Bangs, there could well be recurrences.


How to correct play RAW audio files with one Instance of MediaPlayer?

Question: I don't think what is good but it's works.
I want know is it rigth what i do?
I have 2 files tick.wav and tock.wav wich must be played by timer tick or tock. setLooping not good because i need play by timer init.
So i try two methods:
First
I have variable MediaPlayer mp;
When i need play tick i call mp=MediaPlayer.create(context,tickID), when i need play tock i call mp=MediaPlayer.create(contenxt,tockID)
When i call mp.start();
Some time it's work good and i hear tick and tock, but then i start getting errors from mediaplayer. I think this because previous instance of MediaPlayer is still playing file.
Second
So i do next: i create two variables
tickPlayer=MediaPlayer.create(tickID);

and
tockplayer=MediaPlayer.create(tockID);

and then i need tock i call tockPlayer.start() when i need tick i call tickplayer.start()
I't works, but (always exists but) what me do if files will be more than 2, maybe 100?
Create array of mediaplayers like Vector<MediaPlayer> mpPlayers?
And call needed? I think it's eat my memory quickly.
So target is: i need correct playing files with shortime reaction of mediaplayer from RAW soruce, how ca i do what?
Answer: May be you don't need Vector to store media files, I think you can use java reflection to get information about "raw" resources as raw is static class from R.java.
And are you stopping media player. tickPlayer.stop().


What happens when the airline company scans your passport at the check-in counter?

Question: My dad bought tickets for an international flight a couple of months ago using my US passport and when we checked in at the counter I accidentally gave them my French passport for them to scan. Then, at the security check, I gave them my US passport. Everything went smoothly but I would like to know what happens when the airline company checks/scans the passport at the check-in counter. Is the passport just checked to confirm it is valid and/or is the specific passport used tied to the individual and this information is kept in a database. Moreover, would any government agency/organization be able to see, from the check-in scan, what passport was shown to the airline (or would that be taken from what was used to purchase the actual ticket)?
Answer: An exact answer will depend on the airline, the country you are in, and the country/countries you are flying to/through, but as some examples of what will/might happen...

The airline themselves will store the data for future reference.
For flights from the US, the information will be transmitted to the US government via the APIS system.  This will be used for multiple purposes, including exit immigration, no-fly lists, etc.  Many countries have similar systems, especially those that don't generally have physical exit immigration (like the US).
For flights to/through some countries, an electronic check will be done to the government of that country to check that they will allow the person to travel, and have the required documents (visa, travel approval, etc).  This varies a lot from country to country, but as an example for travel to Australia this is done via the Advanced Passenger Processing system which will confirm that the passenger has a valid visa, eTA, or other means to be allowed to enter/transit the country.
The airlines computer system may use the information to flag to staff to carry out a manual documentation check to make sure that you have a suitable visa in your passport for the destination you are travelling to, in addition to meeting any other conditions for travel (eg, return/onward ticket).
The information may be updated in the flight booking, which may then be available to the travel agent that booked the ticket.

Depending on the exact situation it's possible the data will be shared with other parties.
In the situation you described it's possible that your exit from the US was not recorded correctly, as the US government would have recorded an "exit" by a French citizen, and specifically a French citizen who was potentially not legally in the US at the time (based on not having a corresponding entry record), rather than a US citizen.  Odds are that this will not cause any issues in the future, but it would be worth at least remembering that this occurred in case it is raised at some stage in the future, and be ready to answer any questions about it when next returning to the US (where you should use your US passport for entry as is required by law).
Comment: "be read[y] to answer any questions about it when next returning to the US": I've been flying out of the US for years with an EU passport that I have never used to enter the US. No officer or airline agent has ever mentioned it, let alone asked questions about it. Of course, questions could arise in the future, especially as the US tightens its exit controls, but so far it seems that they haven't noticed, or, if they have noticed, they do not care. (I believe the US does not worry about exits that can't be matched to an entry; they're far more concerned with entries that don't match an exit.)
Comment: @phoog Right, but an unmatched exit automatically implies a corresponding unmatched entry (unless you were born in the US, in which case they don't really need to care much).
Comment: @TooTea is does (with caveats as you note), yet the US does not seem to care about that.  This may have changed, as the last time I looked into it in any detail was two or three years ago, and it was brought to my attention when I read about congressional complaints, but unless it has that is how the system works: unmatched exits are ignored.
Answer: Airline tickets are not generally bound to the passport, as you've discovered, but to the name.  It is frequently possible to buy tickets without giving passport information, but airlines sometimes ask for it up front.
The purpose of the passport is twofold. First, it identifies you.  That is, it proves that you are the person whose name is on the ticket.  Second, it establishes that you meet the documentation requirements imposed by the country to which you are flying, perhaps in combination with a visa or other permit.
I routinely check in for flights on the same reservation using dissent passports because I am a dual citizen of the US and the EU, and I fly between the US and the EU anywhere from one to five times a year.  I almost always have a round trip ticket, and I always use the EU passport when I check in for a flight to Europe and the US passport when I check in for the flight to the US.

Is the passport just checked to confirm it is valid?

No.  It is checked for validity and for other things.  In particular, the nationality shown on the passport is taken into account in determining whether the traveler needs a visa, and the name on the passport is checked against the name on the reservation.

and/or is the specific passport used tied to the individual and this information is kept in a database?

The passport is tied to the individual because that is in the nature of passports.  Whether the passport is retained in the airlines' databases is mostly up to the airline.  Some companies allow travelers to create a profile and save their passport data in the profile to ease online check in, for example.  Passport data is usually sent to the destination country in the passenger manifest, where it will be stored in a database at least until the passenger clears immigration control and probably for decades thereafter.  Some countries, notably the US and the UK, receive passenger manifests from departing flights so they can reconcile the departures against arrival records, because they do not have government agents inspecting the passports of departing passengers.

Moreover, would any government agency/organization be able to see, from the check-in scan, what passport was shown to the airline (or would that be taken from what was used to purchase the actual ticket)?

In general, if a government sees any passport data from the airline, it will be the passport that was scanned at check in.  First, this is because passport data may not have been collected at the time of purchase, or it may have been entered incorrectly.  Second, the traveler may have lost the original passport between the time of purchase and the day of travel, or indeed the traveler may be a dual citizen who is required to use different passports for different legs of the journey for legal reasons.
Comment: @Traveller since online check in is usually not possible earlier than 24 hours before a flight, I suspect that any 72-hour deadline is not very strict.  But in any event API data can change.  I've entered incorrect information in the past, a few years ago, and I was unable to change it, but it was corrected by the airline when I arrived a couple of hours before the flight.  For several years I had problems entering my wife's data into Lufthansa's systems as she resides in the US but has no "residence permit." This has also never been a problem at check in.
Comment: @GiacomoCatenazzi in the US at least it's not so much about good faith as having a specific set of documentary requirements that must be met. If they are, there is no fine, regardless of whether the passenger is actually inadmissible.
Comment: Out of interest, does this mean that a discrepancy between the Advanced Passenger Information data that a passenger provides to the airline before the flight and the actual passport presented at check-in doesn't flag up? I've always been paranoid about making a mistake when entering this data in case it affected my being allowed to board. If only the check-in data matters, why are we asked to provide API beforehand (usually within a deadline of 72 hours before the flight)?
Comment: Note: it is also for risk minimisation of airlines. They have proof to governments that you were checked to flight to destination. Airlines are fined, if they allows to flight a non authorized e.g. without visa) person. Then they should proof they did not in malice. You may see it on difficult cases (or with special invitation), where airlines do copies of more documents). As you say: they are not trained, and they do not know all exceptions, but airlines should demonstrate good faith.


What tag should one use to get a question answered with elisp code?

Question: Using the elisp tag is not appropriate, but what tag should one use when when wants a solution in the form of elisp code, not a setting a custom variable, or a key-sequence, or some other mechanism supported by emacs?  Shouldn't there be a tag for that?  Conversely, should there be tags for the other cases too?  E.g. when one wants a key-sequence to use (something like what apropos gives, but possibly specialized for cases one is using a mechanism isearch or works only in a kmacro).  Or something one could use customize to fix.
Answer: I don't think there's a tag for that. In most cases, the differences between what you describe as different kinds of answers are really not that big. It's very common to see an answer of the form:

You can do X with M-x special-feature, bound to M-x C-s by default. You can also set this in your init file with (setq special-feature-mode t). See also the customization group "Special Feature".

Additionally, I don't think we really want to have separate questions for "How do I do X with elisp?", and "How do I do X with Customize?". The answers would be near identical, but would make the search results twice as long.
Comment: Ok, I guess I can understand that perspective.


Is there a common method of transcribing prosody?

Question: I've seen diacritics corresponding to tones (in tonal languages), but asides from that I haven't come across a system for transcribing prosody in my studies. Is there a popular convention people use?
Comment: Do you mean all of prosody (syllabification, syllable weight, length, stress, tone) or just intonation?
Comment: I'm specifically looking for a way to represent intonation, but if there's any systems that incorporate other prosodic features in addition to intonation I'd still be interested. In class we went over common diacritics, so I have some understanding on how to represent tone, length, and stress.
Answer: To my knowledge as of now there is no united way of transcribing prosodic features of language; however the need for one is critical and therefore there are several meetings being held for designing IPrA (internation prosodic alphabet) (ucla page for the description of the meetings)
This proposal is going to transcribe prosodic events at the "categorical phonetic" level of AM. For more details you can visit BU page for the meetings
Also you can see my question here


analog filter magnitude flatness problem

Question: I have designed an analog filter that includes a high pass filter with a cut-off frequency of 5 Hz and a notch filter with a cut-off frequency of 50 Hz.
I want to sample the output signal of the filter and get its amplitude value. But near the cut-off frequencies, the filter response is not flat and causes the gain to change.
For example, if I give a signal with a frequency of 40 Hz and amplitude of 1 volt to the input, I receive the same 1 volt at the output.
But if I change the frequency from 40 to 49, the amplitude gradually decreases.
I can not sharpen the filter response.
What is the general solution to improve this problem?
I have to sample the output signal and get its true amplitude.
Comment: I wouldn't describe this as a "problem" this is just how filters work. The value you see is the "true amplitude"
Answer:
But near the cut-off frequencies, the filter response is not flat and causes the gain to change.

Well, that is necessarily true for any filter: the implementation of abrupt jumps in the amplitude response is impossible.

I can not sharpen the filter response. What is the general solution to improve this problem? I have to sample the output signal and get its true amplitude.

The true amplitude is what you get. You can of course just correct for the filter gain at the individual frequencies.
Other than that, you can of course build a better analog filter (more stages, more complicated, active filters...), but that comes at a high cost in complexity, effort and tolerances.
Instead, the usual solution is to use an analog filter that has a higher cutoff frequency, so that all the frequencies you care about are in the "sufficiently flat" part of your filter's amplitude response (however you define sufficiently flat), and sample at a rate high enough to for that filter. Then, you do the filtering in the digital domain: since your frequencies are very very low, there's really not much samples to deal with, even if your sampling rate is, say, 2000 times higher than your signal frequency.
Building a digital filter that is close to your ideal specification is much easier; but beware, you still can't do an abrupt jump from pass- to stopband; that's still not possible in digital domain.
So, no matter what you do, the first step is always writing down an explicit, hard numbers, no vague-statement filter specification as in, for example:

I need a filter that

has no more ripple than 2 dB in the pass band
the pass band goes from 0 Hz to 49.90 Hz
has at least 50 dB of attenuation in the stop band
the stop band starts at 50.08 Hz upwards.

A single number (3dB cutoff frequency) really isn't sufficient here!
I put in random numbers there – but it's really important that you think about what your application really needs to function. Almost certainly, you do not incur a significant error if, say, you don't suppress things at 49.9999 Hz. So, define a sensible width within you transition from pass- to stopband, and all the methods of digital filter design are open to you. In fact, in most cases, you just plug that very specification into a tool (e.g. pyfda) and just get a filter back.
Comment: Thank you for your reply. Do you think I can get a relationship for gain by giving different inputs and measuring the output at different frequencies? Does this make sense?
Comment: no, that doesn't make much sense. what you get *is* the true amplitude: this is just how a filter works.
Comment: Not sure what you mean by "a relationship for gain".  It sounds like you _might_ mean the filter's amplitude response.  If that's the case, then yes, you put a sine wave in and measure the sine wave out and determine the gain.  If that's _not_ the case then you're off the beaten path of signal processing, and quite possibly are lost.


Can the rate of virtual pair production from vacuum be computed?

Question: Consider for instance the QED Lagrangian. Is it possible to compute the rate of virtual electron-positron creation from the vacuum?
Answer: If you want to consider this in terms of QED, then it is easy. Virtual pair production-annihilation is described by a vacuum bubble diagram where two propagators a contracted into a loop and there are no external legs. These kinds of diagrams are usually thrown away when we consider the partition function of the theory. And there is a good reason for that, as the matrix element of this diagram diverges at momentum $0$ running around the loop. So you might say that the rate of this process is infinite, whatever this means.
And if you are going to ask from the position of conventional QM, then your question is badly posed as vacuum production (i.e., non-conservation of energy) is defined only with respect to repeated measurements of the system which will "define" the rate.


I'm the new dev team boss - some advice please

Question: I've just been put in charge of a software development team, and don't want to stuff it up.
I'm interested to find out what are some of the things you valued most about the best managers you've worked for? And what are some of the things you hated the most about the worst managers you've worked for?
Comment: Open-ended, list-generating questions are off-topic. This question is really an opinion poll, and doesn't fit within the guidelines defined by our help center. If you can rewrite it to allow for a canonical answer, it may be reopened.
Comment: I'm voting to close this question as off-topic because it is not about Project Management. Your question may be more on-topic at Stack Overflow or Developers Stack Exchange sites.
Comment: StackOverflow is for code not for developers management. Programers is for designed, still not developpers management. The question fits here but is quite broad. Maybe this should be rephrased like : what's the principal point of software development management this could lead to point like explaining that a lot of code is not UI, what is a technical debt,....
Answer: Do:

Give lots of credit where credit is due; a lot of code is under the hood and nobody really gets to see or use it directly
Become somewhat knowledgeable in the field
Give incentives (Employee of the month or outings or bonuses)
Find out what people are doing and why
Remember that programming is brain-work; someone staring out the window or pacing around may be doing more work than the person bashing away at the keyboard
Get access to the bug base and version control system so you can see work happening in real time, understand the throughput rate of the team and get a feel for the status
Read the specification documents and become an early user of the software so that you can make knowledgeable decisions about future feature request and reported bugs

Don't:

Don't give advice on things you don't know much about
Don't try to get people to work harder or longer hours
Don't accuse people of not working on their project; rather find out what they were doing instead (usually helping other people with their coding issues)
Beware of refusing to purchase software/hardware that they request; unless you really understand why they don't need it
Don't argue about schedules and deadlines; it's not usually possible to code faster - unless you want poor quality code. (And if you don't understand that, then review to Become somewhat knowledgeable in the field)
Comment: I'll complete the last point : if you're not technical, don't argue about technical point. However if a task is said by your developer to be too long to fit, you can ask to them if there is a way to answer your need in another way that will still fit be be cheaper


Visiting UK, US passport expiring within 2 months of visit

Question: I'll be travelling to the UK (London) at the end of March for about a week from TLV. I am a dual US/Israeli citizen and will be entering the UK on my US passport, however it expires on May 7, 2017. Is this going to be a problem? Do I need to rush renew my US passport?
Comment: Any reason for not using the Israeli passport?
Comment: In that situation, they have the *option*, but not the *obligation* to exercise Paragraph 21 in a way that's unfavourable to you. Possibly Paragraph 23 would kick in. The actual result is at their discretion and hence indeterminate.
Comment: @PeterGreen You make it sound like he needs to. His US passport will be just fine.
Answer: To enter the United Kingdom, a passport valid for the duration of stay is required by all nationals, except EU nationals holding a valid national ID card.
World Travel Guide
Answer: No, you'll be fine as long as it's valid for your whole visit.
As stated by Timatic, the database used by airlines:

Passports and other documents accepted for entry must be
    valid for the period of intended stay.


27 1 3/8 tires on 27 1 1/4 rims

Question: I have a bike with 27 1 1/4 rims. I plan to buy  a pair of Kenda K161 (27 1 3/8) because the roads get really slippery during the winter. Will these tires fit on my rims? I aldo don't want to buy a new 200c wheelset because it's expensive. Another option is DIY studded tires but buying these tires seems the cheapest option.
There is a similar question here but the answer isn't really conclusive.
Comment: That question is you pointed out seems pretty conclusive.  27x1-3/8 should be the same circumference as 27x1-1/4, but the tire will be slightly wider.  Whether that fits on your bike will depend  on the rim width as well as how much clearance you have.  The width isn't that different so the rims should be compatible, and older bikes usually don't skimp a lot on the clearance like newer bikes do.
Comment: Should not be a problem, so long as all the components are "standard".
Answer: Tires that are 27 x anything all have a bead seat diameter of 630 mm, so they should fit on the rim as the tire diameter is the same.  (Assuming of course your current tires (27 1 1/4) fit correctly). That leaves the following questions:

Are your rim width wide enough for the wider tire?
Does your frame have sufficient clearance
If you have fenders, do your fenders have sufficient clearance.

The widths of the two sizes in question are 32 mm  and 35 mm respectively, which is a small change in width, so it is likely that if again if your current tires (27 1 1/4 tires) currently fit correctly, the slightly wider tires should be fine.
Finally, whether or not the Kenda K161 are appropriate depends on what you mean as "slippery".  If "slippery" means wet, then the tire compound matters most (bicycle tires are too narrow to hydroplane), look for soft tacky rubber. If "slippery" means compacted snow, then the lug pattern (see below) could help.  If "slippery" means black ice, few if any tires will be sufficient (maybe the Continental Top Winter Contact, but I have never used them). If "slippery" is actual ice, then studded tires are best.
Kenda K161

27 1 3/8 tires on 27 1 1/4 rims


What is more objectionable to Christians: Satanism or Atheism?

Question: What does the Christian religion find more objectionable: the worship of Satan, or the non-belief in a God.
Comment: It's important to note that Satanists consists of (very few) people who accept Satan's existence, worship him, maybe eat babies and whatnot (this is more commonly an accusation by Christians, especially historically), but also consists of people who view Satan as a metaphorical figurehead to oppose Christianity, and commonly the harm it does. Also, atheism includes those who are uncertain (agnostic atheist), and those who are certain that no gods exist, they may or may not have heard of Christianity, and may or may not try to convince others of their position. All that shouldn't be conflated.
Answer: One would have to make some sort of survey to answer the question regarding the two alternatives offered, by the question, regarding Christians.
To my own mind, it is clear what Jesus Christ's values were in that his most vigorous and his most comprehensive censuring was against neither of the above but against hypocrisy. I can think of no stronger words which he uttered on this earth which were so condemnatory against particular characteristics.
Jesus of Nazareth pronounced an eight fold 'Woe' (a witness to the four corners of the earth) against the leaders of religion, in the days of his flesh upon earth, which leaders held the outward positions of religious power over the people yet rejected the real kingdom of heaven, selfishly coveting their own power and their own position despite that it was sheer hypocrisy for them to maintain it in the face of the witness of both John the Baptist and Jesus of Nazareth to their falsity and their greed and their covetousness :

But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves, neither suffer ye them that are entering to go in.
Woe unto you, scribes and Pharisees, hypocrites! for ye devour widows' houses, and for a pretence make long prayer: therefore ye shall receive the greater damnation.
Woe unto you, scribes and Pharisees, hypocrites! for ye compass sea and land to make one proselyte, and when he is made, ye make him twofold more the child of hell than yourselves.
Woe unto you, ye blind guides, which say, Whosoever shall swear by the temple, it is nothing; but whosoever shall swear by the gold of the temple, he is a debtor! 17Ye fools and blind: for whether is greater, the gold, or the temple that sanctifieth the gold? 18And, Whosoever shall swear by the altar, it is nothing; but whosoever sweareth by the gift that is upon it, he is guilty. 19Ye fools and blind: for whether is greater, the gift, or the altar that sanctifieth the gift? 20Whoso therefore shall swear by the altar, sweareth by it, and by all things thereon. 21And whoso shall swear by the temple, sweareth by it, and by him that dwelleth therein. 22And he that shall swear by heaven, sweareth by the throne of God, and by him that sitteth thereon.
Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone. 24Ye blind guides, which strain at a gnat, and swallow a camel.
Woe unto you, scribes and Pharisees, hypocrites! for ye make clean the outside of the cup and of the platter, but within they are full of extortion and excess. 26Thou blind Pharisee, cleanse first that which is within the cup and platter, that the outside of them may be clean also.
Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which indeed appear beautiful outward, but are within full of dead men's bones, and of all uncleanness. 28Even so ye also outwardly appear righteous unto men, but within ye are full of hypocrisy and iniquity.
Woe unto you, scribes and Pharisees, hypocrites! because ye build the tombs of the prophets, and garnish the sepulchres of the righteous, 30And say, If we had been in the days of our fathers, we would not have been partakers with them in the blood of the prophets. 31Wherefore ye be witnesses unto yourselves, that ye are the children of them which killed the prophets. 32Fill ye up then the measure of your fathers.
Ye serpents, ye generation of vipers, how can ye escape the damnation of hell?

Matthew 23 : 13-23 KJV
Answer: I would argue for atheism.
Satanists are certainly opposed to God... but they recognize that God, or at least Satan, exists. "You believe that God is one; you do well. Even the demons believe—and shudder!" (James 2:19)
Many atheists are adamantly opposed to Christianity and are quite zealous to convince Christians that God-belief is delusional... when it is they themselves that are deluded. "18For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. 19For what can be known about God is plain to them, because God has shown it to them. 20For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse." (Romans 1) "10...they refused to love the truth and so be saved. 18Therefore God sends them a strong delusion, so that they may believe what is false..." (2 Thessalonians 2)
Both groups oppose God and promote all manner of evil. Both proselytize... but the persecution from atheists is, in my experience, more vicious, and their denial of Truth more complete.
Answer: The answer depends somewhat on  the type of atheism and the type of Satanism. However, Satanism has little intellectual or moral power and is not a great threat either to Christianity or the world. Atheism, however, especially militant atheism, has done great harm and continues to be a real threat. Some forms of Satanism are bizarre and meant to offend Christians, but atheism is more objectionable because it poses a more serious challenge and threat.
There are several branches or forms of Satanism:

Devil-worshipers. (Also known as "adolescent Satanists" because they tend to be unorganized teenagers who grow out of it.) They believe Satan is  an evil god, but one to be worshiped rather than shunned.

The Church of Satan  In this religion, neither God nor Satan are actual beings; the only "god" is the Satanist himself.

Temple of Set. A breakaway group from the Church of Satan this group worships a being sometimes called Satan, sometimes Set, based on the ancient Egyptian notion of "self-creation."

Luciferians This group sees Lucifer is seen as a creature of enlightenment, the who brings light out of the darkness.

The are several other religious groups and fads that fall into the general category of Satanism.

There are two main types of atheism:

Philosophical atheism. This is simply the belief that God does not exist.

Militant atheism. This seeks to impose its belief on others through the power of the state. The prime example of militant atheism is Marxism-Leninism.

Conclusion. In Christian belief, Satan is the prime force of evil and does tremendous harm. But Satan is probably not a Satanist. As C.S. Lewis taught in the Screwtape Letters, the greatest victory of the Devil world be to succeed in convincing humankind that God does not exist. Therefore, atheism is a greater threat to Christianity than Satanism, as the latter has never amounted to much and never will. Philosophical atheism at least respects the freedom of Christians to believe and organize as they wish. Militant atheism is the most objectionable of all, having ruled more than 1/3 of the world in the 20th century and still representing a powerful force in China, Cuba, North Korea, universities, and political parties throughout the world.
Comment: Militant atheism is also a powerful force in Europe, Canada, and (to a slightly lesser but growing extent) the US.
Comment: Yes... I was think of that when I mentioned universities and political parties
Answer: In Matthew 12:30 (ESV), Jesus says "Whoever is not with me is against me, and whoever does not gather with me scatters."  This is in response to various people accusing him of being in league with demons, but, even out of that context, the message is clear: you're either actively supporting Jesus, or you're supporting a creed that is working against him.  Satanism and atheism are equally objectionable in principle, because the objectionable thing is not the details of the false belief but the fact that there is any belief contradictory to the word of God at all.
In practice, different Christian groups will at different times be more worried about one or the other.  Most non-Christian people I know are some variety of atheist, so the arguments I make in defense of my faith are usually tuned for that.  If you just listened to me talk to my friends, you'd assume I found atheism much worse than Satanism for that reason.  I would in fact be neither happy nor sad if my friends all suddenly became Satanists (although I would probably wonder what could possibly have caused this); what would make me happy is if they all became Christian.
(I'd also note that, since all efforts to frustrate Christianity are products of Satan, atheists are in one way just Satanists who don't know it yet!)
Comment: Welcome to Christianity.SE! and thank you for your contribution. When you get a chance, please take the [tour] to understand how the site works and [how it is different than others](https://christianity.meta.stackexchange.com/a/1809/50259). I would also recommend reading the [Help Center's](https://christianity.stackexchange.com/help) sections on asking and answering questions.
Answer: There are certain differences between atheists and devil worshippers. Atheists do not have a motivator .They come together with identical ideologies and go public challenging the faithful. Devil worshippers have their motivator who pulls them back from accepting the True God. Since their activites are not accepted by the common public,they practise underground and are seldom seen imposing their ideologies on the public. Thus, looking from the point of spiritual safety of the Christian faithful, the group of Atheists appear to be more dangerous.
Answer: What is more objectionable to christians: satanism or atheism?
The short answer is satanism.
Atheism in its' broadest sense, is an absence of belief in the existence of God. Atheism do not in itself preclude a genuine search for God's existence.
Whereas followers of Satanism have Satan as their leader. A Demon who hates and desires to destroy everything the is Christian and holy!
Recall what St. James says about the Demon:

Thou believest that there is one God; thou doest well. The devils also believe — and tremble. - James 2:19

Or St. Peter:

Be alert and of sober mind. Your enemy the devil prowls around like a roaring lion looking for someone to devour. - 1 Peter 5:8

Scriptures have many references to the Devil, Satan and the Demon try to ruin souls!
This is the leader of Satanism. Modern Satanism will wash down this point of view, but the reality remains in tack: Satan desires the ruin of the Kingdom of God.
If their is any doubt just ask an exorcist. The reality of Black Masses still happens in modern times!

The Catholic Archdiocese of Oklahoma on Thursday dropped a lawsuit filed a day earlier against a Satanic church after it turned over to a Catholic priest a consecrated host, or communion wafer, Satanists planned to use in a "black mass."
"I am relieved that we have been able to secure the return of the sacred Host and that we have prevented its desecration as part of a planned Satanic ritual. I remain concerned about the dark powers that this satanic worship invites into our community and the spiritual danger that this poses to all who are involved in it, directly or indirectly," he said.
A lawyer for the Angra Mainyu Satanic group named in the suit turned over the communion wafer on Thursday.
The Catholic Archdiocese claimed the communion wafer was obtained "by illicit means." Adam Daniels, leader of Angra Mainyu, said the wafer was sent to him from a priest in Turkey who is also a Satanist.
Daniels said the Angra Mainyu will instead use Black Forest bread from Germany in its ceremony, set for Sept. 21 at the Civic Center in Oklahoma City. The use of Black Forest bread, Daniels said, is a practice that dates back to the 1600s.
The Black Mass of Oklahoma has been held for several years and has faced resistance from state and local leaders as well as setting off anger in a state where many identify themselves as deeply religious Christians.
The black mass is a modern ritual to celebrate the perversion of the Catholic Mass, Angra Mainyu said. The group will also hold a Satanic exorcism, designed to drive out the "Holy Ghost" from a person, it said. - Oklahoma Catholic bishop drops suit over planned 'black mass'

All Satanist tend to target the Catholic Church often, other Christian denominations are targeted also.
Here follows a YouTube video on this subject matter:

A Dark Journey into Satanism - Forbidden History - S03 EP6 - History Documentary
Answer: Based on Jesus's words to John in Revelation:

I know thy works, that thou art neither cold, nor hot. I would thou wert cold, or hot. But because thou art lukewarm, and neither cold, not hot, I will begin to vomit thee out of my mouth. (Revelation 3:15-16 Douay-Rheims 1899 American edition)

This might sound strange, but Jesus, according to His own testimony, has an easier time dealing with pure evil (Satanists) than with neutrals (atheists). Evil in the long run causes less suffering to the evil man (possibly because it's self-limiting?) than the neutral man, like the atheist.


Is there a way to use 'publicly_queryable' => false only on specific taxonomy term?

Question: I have a custom post type that uses the main single page only on specific terms, but others really don't need the single. I want to avoid a user accessing the permalink for all of the terms but one. I imagine there must be a way to "extend" the main custom post type rule to be used only on specific terms but not sure. I guess there's no "official" wordpress way of doing it but maybe using custom functions? Any clues?
Answer: ok - so this isn't what I wanted but it does the trick.
Adding a function to redirect when the user hits any term but one:
<code>function my_page_template_redirect() {
    if( is_singular( 'custom-post-type' ) && !(has_term('term', 'custom-taxonomy')) ) {
        wp_redirect( home_url(), 301 );
        exit();
    }
}
add_action( 'template_redirect', 'my_page_template_redirect' );
</code>
Answer based on this one: Disable Single Post View for Specific Taxonomy on Custom Post Type


Do MacBooks slow down when not connected to power?

Question: I recently read about a device that reported its "minimum CPU speed" (which was 50MHz; max was 1500MHz) and I wondered if my MacBook Air (and other devices like iPhone/iPad) slows down the CPU when not plugged in.
Answer: Yes. Intel calls it "SpeedStep." Variable CPU clock speeds that adjust to conserve power based on demand. The feature is engaged whilst the device is on battery power. All Apple products support this feature (it's actually supported at the hardware level and the operating system's kernel) but since desktop devices don't have batteries, you'll never experience it on anything that isn't mobile.
Your MacBook Air supports SpeedStep, as does the iPhone, iPad, and the traditional MacBook Pro.
More info on SpeedStep: http://en.wikipedia.org/wiki/SpeedStep#Mac
Answer: I haven't seen any evidence that the MacBook Air scales down its CPU to preserve power under normal circumstances.
That said, when your battery runs very, very low, you will probably notice significant slowing. Whenever I play a high-quality game on battery power, the game inevitably slows to a crawl when my battery drops below about 8% capacity. Plugging in will immediately increase performance, so this is clearly the intended behavior.

The iPhone and iPad (and iPod) on the other hand are portable and not meant to be used when plugged in. They should maintain their CPU cycles when running on battery.

@Siddhartha's statement regarding iOS devices rings true for laptops as well, since they are both designed to be used primarily on battery power.


How do I replace commas in a string

Question: I want to remove all commas from a string using regular expressions, I want letters, periods and numbers to remain just commas
Comment: Come on people, these downvotes are not helpful without an explanation (and they're useless since jim is still at 1 rep). So hi Jim, and welcome to StackOverflow. You can see that many people didn't like your question and downvoted it, probably because it doesn't show much effort on your part. As Ed suggested, you might want to show where exactly you're stuck, and perhaps also explain the context of the problem. The way you've written it now, it doesn't make much sense. You can edit your own question to make it clearer. Also, you might want to read the FAQ (link on top of this page). Cheers!
Comment: possible duplicate of [Stripping the single quote (') character from a Python string](http://stackoverflow.com/questions/3151146/), [Remove specific characters from a string in python](http://stackoverflow.com/questions/3939361/)
Answer: Why a regex?
mystring = mystring.replace(",", "")

is enough.
Of course, if you insist:
mystring = re.sub(",", "", mystring)

but that's probably an order of magnitude slower.
Comment: I had the same issue with an exercise. The replace method is a nice toDo when the commas don't have spaces after. Otherwise, if it has a space after, it will create a double space.
Answer: You don't need RE for that trivial operation. just use replace() on string:
a="123,asd,wer"
a.replace(",", "")

How do I replace commas in a string


Is it possible to transpile C# version 10 or 11 code to older versions of the C# language?

Question: Is it possible to transpile C# language version 10 or 11 source code to older versions of the C# language? Just like there are transpilers for Javascript to port code written in newer versions of Javascript to older versions of Javascript.
Comment: I don't think so. Because not all the new features are pure syntactic sugars of existing features.
Comment: Bear in mind that there have been CLR changes to accommodate certain language features. Most obviously, if you wanted to transpile back to C# 1, everything with generics goes out the window.
Comment: You need to take into consideration that C# Versions and .Net Versions are not really independent of one another.
Answer: No. But that is not the important question.
C# code is compiled to CIL code, that is executed by the runtime. Some language features are "syntactic sugar" and can be used on any runtime. These can typically be used by just setting the langversion to "latest" in the project file.
Other features, like the new "generic math", require new runtime features, so it cannot be used with older runtimes. So if you want to use the new features you would essentially have to bundle the entire runtime with your application, and that is already one of the ways .Net core applications can be deployed. So just create a self contained deployment bundle.
Answer: Nothing pre-rolled. Some features can be represented in down-level languages -and some tools offer similar features - for example, IIRC "Reflector" allowed you to specify the language version when decompiling IL, but: decompiled code can also frequently include things that can't actually be represented in pure C#, and: not all up-level features can be represented in down-level C#. Simple features like simple properties: sure, but: they're not hard to do manually anyway.
In most cases, however, you can use an up-level C# version on a down-level project, by using the <LangVersion> element in the csproj; for example, <LangVersion>10</LangVersion> or <LangVersion>latest</LangVersion>. This is probably the better route to explore here. Some language features demand runtime support - which makes them framework-version dependent; some language features just require specific types to exist, and will work if you define those types locally or import them as a package (for example, Microsoft.Bcl.AsyncInterfaces).
Comment: @DotNETAfficionado I don't know a lot about VSTO, but in general: if you deploy as *compiled binaries*, then the language version shouldn't matter - but if VSTO has special project types that don't work in SDK-style project files, then ... it could be painful; if you deploy as *source scripts*, then: I expect that to not work.
Comment: Thank you this is the most useful answer (the answer by JonasH was also helpful), mostly this is about going back to C# 7.3 and .NET Framework 4.8 and using C# pattern matching features of the later language versions wondering if I could use these by setting the LangVersion to C# 10 in a Office VSTO add-in project!


9 vs 12 months distributed pay options and quiting your job before the end of the school year

Question: What if you opt for the 12-month pay but quit your position before the end of an academic year? (For example, give 30-days notice in December). Do you forfeit your 3 months of distributed pay that would have been paid over the summer months?
Comment: Hi and welcome to Academia SE. Could you please specify the country? The answer to "what if" questions is fairly dependent on the country, and frequently on the institution too. Further, what kind of position?
Comment: This would be a question for a lawyer, but I would be surprised if you keep the pay.
Answer: This probably depends widely on country (etc.), but the most logical solution would be that if you have fulfilled X% of the contracted duties then you are due X% of the agreed upon salary.
There might be penalties charged, however, if you cause disruption and it is expensive to find a replacement. But that isn't related to pro-rating. But any signed contract should spell that out, perhaps in a clause referring you to a stated policy.
But pro-rating the salary, when there are no duties over the extra three months is just an accounting trick that makes it possible for faculty to have a regular paycheck, easing their own financial considerations. It isn't a "gift" in any way that can be withheld. You have earned the money for the work you've done.
The HR department can help you answer the specifics if you are actually contemplating this. It probably isn't necessary to consult a lawyer unless bad things actually happen.
Answer: In my experience, your pay stubs will actually itemize "summer savings" separately -- so you'll see the full 9-month salary, and then among your other deductions (taxes, etc.), you'll see that 1/4 of your salary is applied to a "summer savings" account. Whatever money is in that savings account when you quit will be paid out to you; it is your money that was paid in consideration of duties already performed. Whether it is paid out immediately or over the summer as planned will depend on your institution's policies (though I suspect immediately is more likely, so they can "close the book" on you).


Fixing Ambient Occlusion?

Question: I'm having a weird problem with my Ambient Occlusion map. For some reason some bits are completely black (in places where shading wouldn't make any sense). Every other place I check says that I have to recalculate normals, but that doesn't have any effect. How can I fix this?
Comment: In edit mode hit N button in 3D view window to open properties panel, scroll down to Mesh Display section and enable normals on faces. Check if they are not facing inwards, if they do, select the faces and hit Ctrl+N, recalculating normals on whole mesh doesnt work properly some times when there are disconnected parts of the mesh present
Answer: As well as Recalculate, there's the "Flip Direction" tool in the Shading/UVs tab of the tool panel, you can try using that on the specific selection where there's a problem.

Fixing Ambient Occlusion?


Are code related issues in scope?

Question: I was curious to know are code related questions in scope for ebook stack?  Such as <code>.ncx</code> file issues, `.opf structure from ePub 3.0 VS ePub 2.0, how to extend validation frameworks, etc, etc.
Comment: There seems to be enough of a consensus in the answers+votes that you should consider accepting one :)
Answer: For the immediate future we are being more accommodating so we can see what questions are coming in. When we have enough of a sample size we can better decide what will be in scope or out.
That said, one of the topic areas of this site is ebook authoring, which by extension likely includes production.
Comment: FYI you have we repeated in the first sentence. I can't edit your answer here, I'll leave you to decide whether to remove the second 'we' :)
Comment: @JulianHarty Good spot. Fixed, and added a missing word.
Answer: I would like topics related to the structure of ebooks to be on topic and included in this stackexchange site. They're intrinsic to the books themselves; and the devices, the formats, etc. are all on topic.
By sharing our understanding of the structures, how to create, modify, and use them, we may help people to publish and repair ebooks.

Are code related issues in scope?


What is the short form for 'little' ? Is it li'l or lil'?

Question: Where does the apostrophe go in the short form for 'little'? Is it li'l or lil'? What about no apostrophe?
You can find examples of each online:

Lil' Choo-Choo Johnson, Bluesman
Li'l Santa
Secret Rescuer Lil Buddy and His Adventures

However, dictionaries like Lexico don't have entries for any of the forms.
Comment: Why the down votes?
Comment: The apostrophe is used to indicate elision: in cases like this, the letters dropped. That makes it "Li (tt) le" --> "Li **'** le" and with the last *e* being dropped as it is anyway silent, --> "Li **'** l" that is, "**Li'l**."
Comment: @Kris (1) If you're using the generalised definition of 'elision', as is necessary here (uses of the apostrophe in English: (a) The marking of the omission of one or more letters [Wikipedia]), li'l' would be more logical, and lil' justifiable by a tweak of your explanation. (2) the answer below spells out the actual situation rather than the situation predicted by shibboleth.
Comment: @EdwinAshworth There's no 'explanation' in the answer(s) below (?) further than the common sense, aka 'shibboleth,' above :)
Comment: @Kris But your 'answer' (in your comment) isn't accurate. The most commonly used variant seems to be lil'.
Comment: *"Lil" is a kind of prefix and is the short form of "little". It is often spelled with an apostrophe as "Lil'" or "Li'l".* (WP) HTH.
Comment: There is no correct spelling. These are nonstandard, dialectal, and individualistic fast-speech pronunciations -- often involving glottal stops and syllabic resonants -- that are not represented in English spelling, and are therefore considered substandard by people who have learned to spell correctly, but still believe the sounds come from the letters instead of the other way around.
Comment: The ultimate authority on this question would be [Li'l Abner](http://lil-abner.com/wp-content/uploads/2013/06/lilabner.gif).
Comment: Nowadays we do not do two apostrophes for a contraction.  But I recall C. L. Dodgson (Lewis Carroll) advocating things like *sha'n't* with two or more apostrophes.
Comment: My preferred form is *l'lle*.
Answer: Ngram shows li'l beating out lil' and li'l' since before 1900.  (Note that you must press "Search lots of books" after clicking on the link.)
And since Lil is a very popular name (both as a first name and as a hyphenated portion of an apparently Arabic name), any Ngram results for that variant must be ignored.
But as @sumelic points out, the Ngram results are highly suspect, due to the inconsistent algorithm which Ngram apparently uses to process the single quote symbol.  But even if we ignore the Ngram results, the following argument is still quite strong:
Li'l is understandably common since 1934 since the comic strip Li'l Abner was published from 1934 through 1977.  This strip was extremely popular and was at one time read (in 900 newspapers) by 70 million of the then 180 million Americans, likely well over half of the adult population.  Considering that hundreds of newspapers published this strip daily for 43 years, the frequency of li'l appearing in print almost certainly outstripped any other version by an order of magnitude.  Likewise, since the strip was so highly read, the familiarity of the public with the spelling li'l would have been far above their familiarity with any other version.  (But it's interesting to note that, according to Ngram, the li'l version was more popular since about 1900, well before the strip started.)
(Li'l Abner is a worthwhile subject of study for other reasons, since it is responsible for creating outright or popularizing several words and phrases.)
Comment: @sumelic - Granted Ngram has a lot of limitations, but it's about all we have, other than the obvious fact that *Li'l Abner* appeared daily in hundreds of newspapers for 43 years, in terms of publishing frequency easily obliterating any other variant.  And `li'l` was the spelling observed more or less daily by 70 million people over that time, making it incredibly unlikely that any other variant was better known.
Comment: @HotLicks, Re "*since Lil is a very popular name any Ngram results for that variant must be ignored*", is there a way to search by a *particular* meaning of the homograph?
Comment: @Pacerier -- You're welcome to crawl through the help text for Ngram to see if you can find a way to get a more precise/meaningful result.
Answer: The form lil is used, but the most common variant seems to be lil' (capitalized when it is a name).
Wikipedia

"Lil" is a kind of prefix and is the short form of "little". It is often spelled with an apostrophe as "Lil'" or "Li'l".
When used as a prefix in comic or animation it can refer to a specific style of drawing where the characters appear in a chubby, childlike style. These are normally characterisations of adults (real or fictional) and are particularly common in Manga or satire (such as Lil Bush).

and some examples (also from Wiki)

Lil' 1/2 Dead, American rapper
Lil B, American rapper
Lil'B, Japanese pop duo
Lil Bastard, American wrestler
Lil Bitts, Trinidadian musician
Lil' Boosie, American rapper
Lil' Bow Wow (today only Bow Wow), American rapper and actor
Comment: _It's lil of course, but the most common seems to be lil'_ is nonsense, and spoils a good answer.
Comment: @Josh61 the capitalization seemed to earn you some down votes
Comment: But Josh61 does add support for his counter-claim that the unapostrophised variant is the more common. And he got to the Wikipedia quote first. Though you attributed it the right way.
Comment: " "Lil" is a kind of prefix " ??  the whole concept of quoting "wikipedia" is just hilarious.
Comment: I would bet you that "Li'l" appeared in print 100 times more often than any of the other variants, from around 1934 through 1977, at least.  The reason for this is that [Li'l Abner](http://en.wikipedia.org/wiki/Li%27l_Abner) was a very popular cartoon strip, carried by most newspapers that carried any "quality" cartoons.  And probably at least half the adult population read the strip.  The strip is credited with creating several words outright and popularizing many other words and phrases.
Comment: `li'l` would be semantically correct, correct? `lil'` is just wrong.
Answer: What I learned in grammar school in the 1950s and 1960s
(And explaining in plain baby language where the ' goes when you shorten a word)
When you use the short form for a word, you put the ' in place of the letters
that were left out to make the word's short form.
For example, the short form for the word LITTLE is LI'L.
Like "My dog is a li'l angel."
You are leaving the two letters T and T out, and so in their place goes the ' to indicate where the letters were omitted to take the word from long to short.... In this case, the E at the end of LITTLE is silent anyway, so it's not even treated. It's just dropped.
It's is the short form for It is. - The I in IS is left out and the apostrophe is put in its place to indicate where the letter was dropped to make it a short form word.
Hasn't is another example.  The apostrophe goes where the o in not is omitted.
And so on...
Comment: You say it's **L'IL** but then write "My dog is a li'l angel." Can you fix the spelling please?


Can the type of a previously created ZFS pool be changed?

Question: I have a 2-drive zfs pool created in mirror mode. Now I've managed to get my hands on a third drive, and I was wondering if I could add the drive, and change the pool type to raidz, which is pretty much better for three disks.
Answer: the short answer No.
the longer answer. With going from 2 to 3 drives you can do the following.
Step 0. MAKE A BACKUP!
Step 1. Break the mirror by detaching one of the drives.
- this should give you 1 drive with the data in the 'mirror' pool
Step 2. Create a fake drive in the form of a sparse file
Step 3. Create a new Raid-Z volume with the new drive + the previously detached drive + the fake drive
Step 4. Degrade the array by removing the fake drive, leaving you with the 2 actual harddrives in the array.
Step 5. Copy all data from the old pool to the new pool.
Step 6. Remove the old mirror pool, and add that drive to the RaidZ pool.
Answer: No, you can't do this using normal tools... at least not without lots of pain and risk.
If you have the option, you should go to 4 disks and RAID 1+0 or offload the data and recreate the pool the way you want it to look.


Does wake-on LAN/WOL depend on hardware or the operating system?

Question: Does wake-on LAN/WOL depend on hardware or the operating system?  Or both?  How does one send a command to wake up a machine if it is supported (say a Fedora server)?
Answer: Hardware, and the associated firmware that runs on that hardware. It is OS independent.
There are a plethora of WoL utilities to send a "wake up" packet (sometimes called a Magic Packet). Try the port/package management system in your OS (or Google it). It's usually as easy as wol [MAC Address]
Answer: Wake On Lan involves sending a "magic packet" which contains the MAC address of the destination computer.  There's a lot of detail here:

http://en.wikipedia.org/wiki/Wake-on-LAN

The best way to send a WOL request from one Linux box to another is ether-wake.  If you're looking for it in Fedora, install the net-tools package:
$ yum whatprovides */ether-wake
net-tools-1.60-102.fc13.x86_64 : Basic networking tools
Repo        : fedora
Matched from:
Filename    : /sbin/ether-wake

The syntax is pretty darned easy:
ether-wake 00:11:22:33:44:55

Just replace 00:11:22:33:44:55 with the MAC address of the machine you want to wake.
Answer: Both, the hardware is a fundimental requirement but the control of WoL is passed to the os on boot and the os could change if it works or not.
Comment: Please do not spam this website. Thank you. Also, wouldn't the computer have to be on before the OS could change anything? WoL simply turns the computer on, what happens after that has nothing to do with WoL.
Comment: WoL is defined in BIOS but the OS can turn this on or off. Most windows machines have options in drivers menu to enable and disable WoL.
Comment: The OS is NOT involved. In fact the OS isn't even running when the NIC responds to a WoL packet. The WoL packets are NOT passed to the OS at all. Wether the OS can disable WoL capability or not (or try to, because the NIC doesn't have to obey) does not mean the OS plays a part in WoL itself.
Comment: The OS IS involved, if the OS turns off WoL then the NIC cannot wake up no matter what you do.

Read here for non persistent WoL http://ubuntuforums.org/showthread.php?t=234588
Comment: Per wikipedia you're both kind of right: Hardware requirements
Wake-on-LAN support is implemented on the motherboard (BIOS) of a computer and the network interface (firmware), and is consequently not dependent on the operating system (and NIC drivers) running on the hardware. Some operating systems can control Wake-on-LAN behaviour via hardware drivers.
Answer: The following guide goes step by step on configuration and gives good understanding of WOL.  Please read at http://www.thegeekstuff.com/2008/11/wol-wakeonlan-guide-remotely-turn-on-servers-without-physical-access/


Humidity sensing fan installation

Question: I am installing a humidity sensing fan (Delta GBR80H) into a bathroom where no fan existed before, only have a light switch. What is the best way to accomplish this?
Comment: Do you have access from above in the attic?  You'll need a spot to put it, run power to it and then run a duct to exhaust the air outside.
Comment: Hi Richard, I think your question has not gained much attention since it lacks a bit of detail that is required for us to help.  Describe the bathroom, your access from above and provide a picture, perhaps of the ceiling and the attic.  This will go a long way if you are truly stuck from moving forward.
Comment: Hi Gary, thanks for your input. I have plenty of room in the attic to do the install and running the ducting and I have no questions about the physical installation my question is more about the electrical hook up. I can install switches and run electrical if necessary. In my case it appears the humidity sensor needs constant power and another switch for the intermittent fan, just not sure with way to get started. I've also heard about using a smart switch but I'm a couple of decades behind that technology but I do have an Echo plus with a built in hub.
Comment: You can hit "Edit" (it's right underneath your post and the tag `bathroom-fixtures`) in the row of text that says "share **edit** delete".
Answer: You'll have to check the light fixture and the switch to see where the hot wire is.  It can be in the ceiling, with a wire running to the switch to break the circuit, or at the switch and a wire running to the light to power it.  If the hot is in the ceiling, you are in luck.  You can tie into that for power.  If the hot wire is at the switch, you'll have to run a wire down the wall and into that box.  Not impossible, but not easy either, it will be much easier if its an interior wall.  I am an amateur and have done it many times.
I would suggest cutting the power at the breaker, pull off the light fixture from the ceiling, and the switch from the wall.  Then turn the power back on and with the light turned off, carefully probe the wires with a contactless voltage meter to see where the power is coming from.
Answer: I have installed a couple of these I think they were delta  fans, I'm not sure  but the one that I installed I did as follows.
The fan does not need to be wired for constant power. It should be wired with a normal switch.
When you flip the switch up once it activates the fan  to run like a normal fan, if you flip the switch up once back down and then back up again  quickly it puts the fan in humidity mode.  In the first scenario you will see a little yellow light  just inside the grill cover of the fan telling you that the fan is on, and in the second scenario you will see a little blue light which will tell you it is in humidity mode.
On the ones that I've installed there have been two switches, one for the light and one for the fan. But if I remember in the instructions there may be an option for one switch  wiring.
Comment: Thanks Alaska Man, after checking out the Delta website again there is a schematic for a one switch installation that is not included in the instructions that come with the fan. I think I can get it running, will let you know in a couple of days.

Humidity sensing fan installation


Sending database name in request headers

Question: I am doing a project with an architecture of single server and multiple database.
Every client request will contain a header containing database name that this request should connect. Is this a good idea for disclosing the database name ?
Is this a security issue ?
Comment: OWASP is your friend.  Basically,  you are potentially vulnerable to injection, MITM attack and unauthorized access.
Comment: Do you check the names against the list of DBs that a specific user is allowed to access? Do you use TLS to encrypt the channel between the clients and the server?
Comment: @DeerHunter: i didn't put any list & there is no encryption. Can you please explain me what all things I need to take care ?
Also Is this a good idea ?
Answer: This is not a good idea. An attacker could change the database name, supply an invalid one, or put special chars on the database name and possibly exploit a SQL injection. It's possible to do a lot of damage depending on your setup.
You could use server-side sessions, and send only the session token to the user. The database he is connecting to should be stored on the server side session.
Answer: It is a security issue, and tampering with headers, or really, anything that you have on the client side is very easy. You should never trust anything that coming from the client.
I would definitively suggest that you have a white list of acceptable values that is enforced on the server side to avoid SQL injections. This list could be generated dynamically, but make sure that you never, ever, use something that comes from the client in a database connection string or in a dynamically constructed query.
As other have suggested, the database name should be stored on the server-side, in a session token, and not sent through HTTP headers.
OWASP have loads of good information on the subject of SQL injections. See https://www.owasp.org/index.php/SQL_Injection_Prevention_Cheat_Sheet
Comment: Even with session based token you'll want "A white list of acceptable values" and make sure you provide a default action if there is no match...
Answer: If all you are passing over is a simple name which identifies a database to use, then I can't see any immediate problems (provided you do some server side validation).
I would try to avoid using names that give away more info about the database than needed though (e.g. server addresses, system- or version-info, etc). In fact, it might be better to just use a numeric ID or something similar to identify the servers instead. Map this to the actual databases on your server, where the chances of anybody seeing this info is smaller. The less info a client needs to know, the better!
Also, you should verify a user's right to access whichever DB is specified. If a request from a client is manipulated to attempt to access a DB other then the one it should, then logic on the server side should cancel the request, or at the very least verify that the user is in fact allowed to access this other database.


Windows explorer vs Mac Finder, which is better for navigating folder hierarchy?

Question:

What are the guiding design principles behind the two different methods of navigating the folder?
Answer: I'am Windows user and must admit that MacOS Finder is better.

It's overloaded by default (too noisy). Too many unnecessary elements i.e. i don't need 3D Objects, OneDrive and unable to remove it without hacks.
View modes: Finder provides convenient way to switch view modes. Explorer has 8 modes burried inside menus.
Explorer has too narrow columns by default (legacy from age with 1024x768 screens). I'm sure that it's possible to auto-adjust column width by OS.


Mini Synth via external soundcard

Question: I recently bought a Korg Monotron Duo. To record with my laptop that lacks an internal mic I also accquired an external USB soundcard with one mic and two headphone jacks (rather cheap device). The latter device works quite well in regard to hear music from laptop and recording with a mic/headset. But what comes in from the synth is too quiet. And in addition although there is a cable plugged in the headphone jack of the synth, there is quite aound from the internal speaker of it!
If I plug in headphones directly to the synth the output is well and the speaker is quite. That's why I assume the external soundcard to be the weak part. Any opinions or knowledge on this issue?
Thanks in advance.
Answer: It's possibly an issue related to the driver settings of your usb sound card. There is likely to be a microphone gain parameter somewhere in the configuration screens related to the sound card. Try and adjust that to increase the microphone input gain.
You ideally need a sound-card that has a "line" level input port. this would be the correct port to use with a device such as this.
Comment: Thanks, Mark. For this helpful answer. It did not directly solve my problem, but I managed to get a satisfying result installing eartrumpet in Win10.

Mini Synth via external soundcard


Do I have to use categories?

Question: I don't want my blog to use "categories" is there a way to turn them off? I can just not define any but then they are still listed as "uncategorized"
Comment: [This question asks how to do this on WordPress.com](http://wordpress.stackexchange.com/questions/2956/how-to-totally-get-rid-of-category-in-my-blog), but contains some answers on how to remove the category metaboxes - which will only work on self-hosted WordPress installations.
Answer: You're not obligated to use categories. The listing of categories is a function of the theme, you can edit your theme and remove that. Depending on the structure of your theme these may be in a number of places. You can search for instances of get_the_category and comment them out. Look for a file called loop.php first, failing that, your single.php and index.php files.
*edit:
I should mention, it may be the case that your particular theme doesn't allow you to remove the category listing as easily as I've outlined, if you're using a framework based theme where these functions are removed from the normal template structure for instance. In this case you should seek assistance with the support of whomever developed your theme, or choose another.
Answer: There is not a built in hook or filter to unregister a taxonomy (category is a built in WordPress taxonomy).  There is a trac ticket with a patch but it has not been implemented.
I found a solution on Kaiser's Git Hub Page that allows you to unregister built in taxonomies.

Do I have to use categories?


For most journals, do peer reviewers expect common notions such as arithmetic mean to be formally defined?

Question: If making use of standard statistical notions such as arithmetic mean, do peer reviewers still expect to see a formal definition such as μ = ( Σ Xi ) / N, or is the notion so common that it'd be redundant to define it this way?
Comment: Before you learn to write, you learn to read. Surely if you're writing a paper for a math journal you've hopefully read papers in math journals. What do those papers do?
Comment: Thanks, did not say it was for a math journal though. Would you formally define the arithmetic mean for a neuroscience study, for instance? Or would that be perceived as redundant and boring?
Comment: In my experience people don't write formal anything outside of math (broadly interpreted) journals.
Comment: A paper should have all relevant information for reproducing its derivations. You need to define all symbols. If you talk about an average, perhaps it is clear, but if there is any possibility of ambiguity, you need to resolve it. E.g. variance estimators could be biased or unbiased. Etc.
Answer: You do not need to define common "notions" such as the mean.
You do need to define common symbols, such as "μ", because they are common symbols for more than one thing.
These are just broad guidelines.  Each research community has its own practices.  If unsure, avoid ambiguity.
Answer: Statistical journals (and other journals that commonly use statistical results) would not usually require you to define the arithmetic mean of the sample values (called the "sample mean").  However, mu is not the standard symbol for the sample mean.  The standard symbol for the mean of data values labelled with x is an x with a bar over it (and possibly a subscript N if you need to keep track of sample size).  The Greek letter mu is usually used for the mean parameter for the underlying probability distribution, which is a different thing.