Should we have separate tags [vi] and [vim]?

Question: Vim is almost a proper superset of vi, but they're still two different editors, with two different names. Should we create vi and vim?
Comment: **Vim** has all the features of **vi**, **vi** is not all that vim has so we can assist users of two editors.
Answer: The vi tag is unavailable - it's considered "intrinsic" to the site; every question is assumed to be about vi or a derived editor unless otherwise noted.
...Which means it's important to tag questions that aren't about vi with a tag that indicates the specific editor being asked about. Chances are, vim will be the most common tag here - [Update: that's not working either; folks don't use it consistently at all. It's now blacklisted too.] What's not ok is failing to use other tags to indicate the specific nature of the question. You'll need tags to indicate...

...the OS platform being used
...the specific editing feature being asked about
...any relevant add-ons being used

Comprehensive tagging is important to establish early - that's why during this private beta, anyone using the site can create new tags. But do exercise care: more tags are not always better. Strive to create and use tags that are both descriptive of the specific topics being asked about and generally useful to others interested in the same topics.
Comment: That's kinda a ripoff, I'd prefer to assume vim unless otherwise stated. Oh well.
Comment: Like the others said, I think vim should be the default assumption, and `vi` or a more specific tag should be used if the question requires it. Yes, vi is installed on every unix out there, but I'd assume it's mostly used for quick edits and fixes and not so much for more involved work that leads to questions. Surely there will be enough questions that deal with solving a task and having only vi available, but I hope they will be rare in comparison to vim questions and become rarer over the years as vim gains ground. That said, I couldn't find any vi vs vim usage statistics to prove my point.
Comment: You really want vim adding to almost every question, or to assume if we miss 'vim' we meant 'vi'?
Comment: Here's the question, @l4mpi: what's going to be easier, making sure that editor-agnostic questions are tagged appropriately, or making sure that editor-specific questions are tagged according to the editor? Keeping in mind that, for the purpose of this site, [vi] corresponds to "editor agnostic".
Comment: Not sure you got my point: vi and vim solutions are often rather distinct. Thus I'd guesss most questions will editor-specific; the best solution for vi on solaris 6 will most likely work in vim but it will also most likely not be a _good_ vim solution, and the best vim solution will usually not work in vi. Thus the answer to most questions depend on if OP has the full power of vim available; and IMO the default assumption should be they do (which I sadly can't back by statistics). Also, for the purpose of searching answers and questions to answer, a vi tag feels more useful than a vim tag.
Comment: If you're proposing that *both* tags be allowed, you might make a better argument in an answer here, @l4mpi. If you're proposing that [vim] be intrinsic (that is, no vim tag allowed), you should start a separate discussion.
Comment: Yes, I think it would be more useful to have [vim] be intrinsic and [vi] as a sign for "I have to do some work without all those shiny vim features". It depends a bit on the community as well, if most people share my view of vim being the default and thus default to give vim-specific answers even if no vim tag is present. I guess a separate discussion (or feature request as it's a request for changing the intrinsic tag?) would be appropriate.
Comment: Didn't even need to ask it myself: http://meta.vi.stackexchange.com/questions/4/should-questions-and-answers-assume-the-use-of-vim
Answer: I think it might make asking questions clearer. If I ask something about Vi and use the Vi tag, someone will not suggest something that only works in Vim.
Comment: @derobert Having experience from the [TeX.SE] site, I would suggest not: the B.J.'s original should get a longer tag name, otherwise people never use it correctly. We ended with [tag:tex-core] and [tag:plain-tex], and we blacklisted [tag:latex] for question about LaTeX itself in favour of [tag:latex-project]. I would suggest [tag:original-vi] for the B.J.'s version.
Comment: Should the `vi` tag refer only to the Bill Joy original?


Chromalux Electric Boiler Replacement for Radiator System

Question: I have an old chromalux electric heater heating my radiant heaters. Would it be more cost effective to replace it with a gas fired boiler? - and would I have to replace the rads or just tie into them?
Comment: What kind of radiant heaters?  I'm assuming forced hot water baseboards ...
Answer: The answer depends on where you are, what your local energy prices look like,  whether you already have gas coming into the house, whether you're going to be there long enough for investment in a new system to justify its cost...
In my area, gas and oil have historically alternated as most cost-effective, with electric heat always being most expensive.
When I bought it, my house had a 1945 oil boiler, inefficient by modern standards and with a slightly leaky tank as well. I budgeted for replacing it when negotiating the purchase. I personally prefer gas and already had gas coming into the house, so that's what I chose -- a direct-vented high-efficiency gas boiler, with new pumps, feeding the existing radiators.
(Actually,  I was very interested in the small gas-fired cogeneration plants starting to be sold as heating systems ... use the gas to run an engine which runs a generator, sell the electricity to the grid and use the "waste" heat to heat the house -- but for good or ill, they were only available for forced-hot-air systems and I wasn't ready to replace everything or deal with having only one or two trained technicians in the entire state to maintain the thing. So I'm just selling solar to the grid.)
One thing to keep in mind when upgrading a heating system:  Old units drew combustion air from their surroundings, drawing (cold, in winter) replacement air into the house. New units are direct vented, meaning they draw combustion air directly from outside, so you don't lose as much heat out the exhaust.  But their greater efficiency also means less heat lost to their surroundings, so the basement may actually become cooler rather than warmer unless you remove some pipe wrap to get more heat into that space... or add a zone and radiator(s) for the basement.


Mirrorless camera: setting the diaphragm

Question: Do mirrorless (hybrid) cameras like the Sony NEX-x or the Panasonic Lumix GFx let you set manually the diaphragm?
Comment: Did you check either manual or look at one of the thousands of reviews online for either model?
Answer: Yes. Every single mirrorless ever made offers full-manual controls. Some just hide them better than others! Having a mode-dial also helps to quickly set the camera into Aperture priority mode. Fuji lenses for mirrorless cameras all have an aperture ring right on the lens which makes things very easy.
If you are keen on using semi-automatic (A/S/T) or manual (M) modes, I suggest you look for a camera with at least one control-dial. Two is better if you use Manual mode as there is nothing to press to toggle between both parameters. Some mirrorless cameras even have three control-dials.
Comment: Hey, doesn't the OM-D have 3? 1 for mode, 2 for aperture/shutter?
Comment: That would be one *Mode-Dial* and two *Control-Dials*. There are lots of variants too as some camera do not need mode-dials (as opposed to need one but not have one) and others need two controls per parameter!


An example of a context-sensitive grammar for a given language

Question: Consider this language: $L = \{a^nb^ma^nb^m \mid n,m \ge 1\}$. Can we give for this language a context-sensitive grammar?
Comment: [Wikipedia](https://en.wikipedia.org/wiki/Context-sensitive_grammar#Examples) contains a noncontracting grammar, which can easily be converted to a context-sensitive grammar.
Answer: Your request is easily served!
$$\begin{array}{lcl}
   &S  &\to &abab\\
   &ba &\to &bbBa\\
   &Ba &\to &aB\\
   &Bb &\to &bb\\
   &ba &\to &bAaa\\
   &bA &\to &Ab\\
   &aA &\to &aa\\
\end{array}$$

There is some theory to help you make sense of this solution.
Let us first consider a simpler language that manifests the same difficulty: $L = \{a^nb^ma^n ∣
n,m \ge 1\}$. Imagine it as a sea of $b$ between the shores of $a$, if you please.
We would like to grow the shores so that they are always the same size. One immediate way is to
have a collection of rules like $a + b^m + a \to aa + b^m + aa $. But we see it will not serve our
needs, as, our collection being finite (grammars are required to have a finite set of rules),
there is always some choice of $m$ that is not accomodated. So evidently there is a trick.
The trick is to introduce a non-terminal "ship" that will sail across the sea and deliver the
information from one shore to the other. When the left shore grows, it will send a ship to the
right shore, and when the right shore receives a ship, it will also grow, thus maintaining the
required equilibrium. How can we sail a ship? $Ba \to aB$ is one way to move it one unit of sea
rightwards. What remains to be put in place is a shipyard $ba \to bbBa$ and a port $Bb \to bb$.
Here is what we get:
$$\begin{array}{lcl}
   &S  &\to &bab\\
   &ba &\to &bbBa\\
   &Ba &\to &aB\\
   &Bb &\to &bb\\
\end{array}$$
I am sure you can see how to extend this to your original language: you will need the sea
people to also send some sort of messenger golems $A$ across the land to the sea on the other side of
$b$.
Happy adventures in fantasy grammar land!


Restrict particular applications from accessing certain files

Question: Normally the private files stored in the home directory of a user can be accessed by applications running with the effective UID of the user. How can I restrict a particular application from accessing certain private files, while still allowing the files to be accessed by other applications using AppArmor on openSUSE.
Comment: @mutzmatron - this Q is perfectly fine as it is. OP's do not have to do exhaustive research. Often OP's are unfamiliar with the lingo/jargon so it may be beyond them in how to even proceed.
Comment: @sim FYI My comment was in response to the *original* question (http://unix.stackexchange.com/revisions/105535/1) not this edited form.
Comment: Just to point out point #1 http://unix.stackexchange.com/help/how-to-ask, *"Search, and research
Have you thoroughly searched for an answer before asking your question?"*
Answer: AppArmor is a Mandatory Access Control (MAC) Linux Security Module (LSM), used by, amongst other, Ubuntu and SUSE Linux. AppArmor access control rules are defined in AppArmor profiles in /etc/apparmor.d/. The profiles are simply text files, which contain information regarding resources the application the profile pertains is allowed to access.
Typically, when designing profiles, one would exercise the application with AppArmor set to complain mode, in which access control violations are allowed, but logged. Using the logs, one would iteratively refine the profile. When the profile is done, AppArmor can be switched to enforce mode, in which the access control rules defined in the profile are enforced, and any violation attempts logged.
The outline of an AppArmor profile looks like this:
#include <tunables/global>
/path/to/application {
   [...]
}

The #include directives allow statements pertaining to multiple applications to  be placed in a common file, then included into the profile of each relevant application.
The <tunables/global> file, corresponding to /etc/apparmor.d/tunables/global in turn includes definitions that should be available to every profile. One of these additional includes is /etc/apparmor/tunables/home, which together with a @{HOME}/** rw (or similar directive) grant applications access to user home directories.
If this is the case, in order to deny access to certain files in the user home directory, one would need to add a profile rule to explicitly deny access to the files. This can be done using the deny directive, such as in the following example:
#include <tunables/global>
/path/to/application {
   [...]
   # Allow directory listings (i.e. 'r' on directories).
   @{HOME}/ r

   # This is needed for saving files in the home directory.
   @{HOME}/** rw

   # Revoke access to specific file
   deny /home/user/file rwa
}

The would deny read (r), write (w) and append (a) access to  /home/user/file.
An alternative is to add the paths you want to protect to /etc/apparmor.d/abstractions/private-files or /etc/apparmor.d/abstractions/private-files-strict and make sure the AppArmor profile for each application to be affected includes the <abstractions/private-files> or <abstraction/private-files-strict>. These files should already contain rules for common files which should be protected for the purpose of privacy or other security considerations.
For a full list of access mode details and more information on AppArmor security profiles, consult the apparmor.d manual page and Novell AppArmor Administration Guide (pdf).
Answer: [In response to the edited, more specific question.]
To restrict access in AppArmor for a program, foo, create a profile with the entry
/usr/bin/foo {
    /etc/foo/* r,
}

Allows read access to the files in /etc/foo
    /etc/**

would allow read access to all sub-directories in /etc
Conversely you can use
    deny /private/path rwa

to restrict access to a private path.
References

https://help.ubuntu.com/community/AppArmor
http://wiki.apparmor.net/index.php/Documentation
http://www.overclock.net/t/517324/tutorial-secure-ubuntu-with-apparmor
http://ubuntuforums.org/showthread.php?t=1008906
Comment: Actually, this is still not an answer... Links alone are not an answer as they can change but mainly, all links send to generic apparmor manuals... an answer saying read the manual is not very useful... tbh :). Purpose of this site is to help solving specific problems. Not all linux users are IT professionals and their computer is a tool, not their main job. They have other things to do instead of reading all the manuals of all the software installed on it.
Comment: @laurent: unless I'm mistaken it's also not a site to post full blown tutorials - the original question was far broader than the current form (edited by Thomas Nyman).
Comment: @mutzmatron While I tried to improve the language, the question has been all along "How do I restrict access to certain files by certain programs". Your original answer did not address this, and your most recent edit answers the opposite question: "How do I grant access to certain files to a certain program (using AppArmor)". Furthermore, I assume that the OP does not want to create an AppArmor profile from scratch, and the default includes already grant access to all user home directories, as I explained in [my answer](http://unix.stackexchange.com/a/105547/43779).
Comment: @ThomasNyman: not that quibbling about the details is particularly useful, but the OP's original post ended with "how to set the permission of the applications that could not access the the private files, but I can access them or other applications. Can I do it? I hear AppArmor, is it simple? Howto?". While your edit did indeed extract a coherent, meaningful question, the question in it's original form was very broad and open-ended.
Comment: _"...not that quibbling about the details is particularly useful..."_ Agreed, neither is copying information verbatim from existing answers. If you think a question needs improvement, suggest an edit, downvote and leave a comment or flag it. Your site association bonus gives you enough reputation to do any of those things. If you *do* post an answer, please make sure you actually give enough information to actually answer the question.
Comment: @ThomasNyman: 1) FYI I copied information from one of the tutorial sites, not your answer. 2) At the original time of response I did not have enough `reputation score` to perform the actions you suggested. 3) My original response was intended to signal to the OP that they should try google before posting vague and broad questions, given (2).


Coding style when using abstract classes in Java

Question: When inheriting from a base class in a scenario when not all methods will be implemented, is it better to put empty methods in the base class so that sub-classes that don't require that method can ignore it totally, while other classes must override the method if they want to implement it... e.g:
Base class:
public void myMethod() {
}

Sub-class that doesn't implement:
<nothing!>

Or is it better to leave the base class cleaner and just put an abstract method in and force the sub-class to flesh out a blank method if it doesn't implement that method?
Base class:
public abstract void myMethod();

Sub-class that doesn't implement:
public void myMethod() {
}

Comment: You can use interface instead
Comment: The abstract class elsewhere has methods that do stuff. There isnt really the option at this stage to convert it to an interface. I should have noted in the question that I was expecting a lot of "dont use inheritance" answers! :-)
Comment: I would go with the second approach and have the sub-classes actually throw an exception in those methods. This will ensure that the unnecessary methods are not called on sub-classes where they should not be.
Answer: It is your design decision . If you want to force your developers to override myMethod and developed the logic. You should go for abstract class.
Answer: Coding style is up to you, depends on your requirement and everything has it own pros and cons.
In case of abstract class, it is not necessary to put only abstract method. I would recommend you, better to use Interface.
Answer: Whenever it is possible you should
Prefer interfaces to abstract classes
Because interfaces do not permit to contain method implementations, there is the
so called Abstract*Interface*, which is a combination of both technics:
In that case the Interface defines the type, while the abstract class provides a skeletal implementation.
An example are the Collection Framework which provides skeletal implemantations: AbstractCollection, AbstractList, AbstractSet and AbstractMap.
Further info see Josh Bloch, Effective Java 2nd Edition,  Item 18
Answer: Both are not the most elegant solutions, though both can get the job done. Use the design pattern strategy design pattern http://www.newthinktank.com/2012/08/strategy-design-pattern-tutorial/
Answer: It's up to you and it really depends on the situation.
You can use abstract methods when you have an abstract class and you want classes which extend it to implement that method (because the abstract parent class uses the abstract method - it may be something like print()). It's similar to interface's methods but it's usually used in different scenarios. But I would use interface in most cases...
I would use abstract method only in case that myMethod() does a different thing in each class that extends the abstract parent... Otherwise, if myMethod() does usually the same thing and one or two classes need to override it, I will use the first solution.
Also look at the template method pattern. I don't know which case is yours so I can't answer this question in an exact way...
Answer: I think it comes down to whether there is a meaningful default implementation for myMethod(). If there is, put it in the base class and subclasses only override if they need something different.
If there is no meaningful default, and in practice every non-abstract subclass should either implement the method itself or inherit an implementation from an intermediate class, it is a very bad idea to provide a fake implementation in the base class. It converts an error the compiler could have detected to one that can only be found by testing.
One option to consider in some cases is providing a default implementation that throws UnsupportedOperationException.
Comment: Java itself provides for this in certain classes, [see here for an example](http://docs.oracle.com/javase/6/docs/api/java/util/List.html#add%28E%29). This allows `List` to be used in, say, an `ImmutableList implements List`
Comment: This is a good point. But I probably should have pointed out that generally in these cases calling the unimplemented method is not an exception, rather it simply does nothing. E.g. when bullets hit an armoured vehicle, the method need not do anything, but when they hit a car something happens.
Answer: The differenct in an abstract class is that you can but must not override that function.
So public void nothing() {} can be overridden and public abstract void nothing2(); must be overriden.


Frustration in getting admission into PhD Computer Science, with background MSc Geospatial Science & BTech Computer Science

Question: Am presently really frustrated in getting a supervisor and admission into PhD Computer Science in any University in Europe or US. I recently graduated with MSc Geospatial Science with distinction (cgpa 4.8/5) and I have Bachelors in Computer Science. Ever since I finished my masters have been seeking a PhD admission in computer science in any average schools in europe or US, but all to no avail. I have 3 research papers in top international journal, I even had a research proposal of likely topic relating to Mobile Computing & Mobile GIS, and i seriously think the frustration is weighing me down, please is there something am not doing right or there is any other method of getting a supervisor apart from contacting them through email.
Comment: Maybe you could describe in a few words how you have tried to get into PhD positions so far. What did your email contain?
Comment: Welcome to AC.SE. You have told us about yourself, but you haven't told us about how you have been identifying potential supervisors and contacting them. Given the information you have provided, I don't see how we can answer the question.
Comment: Apply for a PhD in GeoSciences instead.
Comment: The email contains information about my educational details, specialization and request to supervise my PhD research, and also my CV and likely research proposal.
Comment: So you want to choose your own PhD subject…. But universities will only have funding in place for subjects they have chosen…..
Answer: At all decent universities. Ph.D. admission is competitive. Apply following the official procedures to a dozen universities. Make sure your application file really is complete and on time at each. You will not be admitted based on contacting faculty informally.
Comment: This is true for US/Canadian/UK universities. PhD positions in continental Europe work very differently.
Comment: no this is not true for all US universities. While contacting a professor won't get you in, having a professor interested in you can help increase your chances if that professor informs the admissions committee to look out for your application. At some places this will help more than others.


getting bch out of my paper wallet

Question: Hi anybody who can honestly and simply tell me how to get my bch out of my paper wallet. I went to blockchain.info and transferred my bitcoin which I had on my paper wallet before Aug 1rst--into their wallet, then safely exported it to an exchange I use--all went well. But I haven't the foggiest how to retrieve my bcc from the same paper wallet now, which I've been told still has the bcc on it. blockchains website is not for a newby like me. I sent their support requesting step by step directions and haven't heard back from them--can anybody give me simple directions on how to get my bcc out of my paper wallet and into my exchange? Please don't assume I know anything and I especially only want to deal with my pc to accomplish this---I have no clue what an app is and don't want to know----Is there someone who's right for this question please?
Comment: when you pose your question like this, you might fall victim to scammers. There are already people here in the forum, that told their story of being scammed. So be very careful once you get contacted, and never (ever!) give out your private key or seed(s) to anyone via Internet - you will be robbed!
Answer: You could download a full client of bitcoin cash like Bitcoin ABC (https://www.bitcoinabc.org/).
After that you can import your private keys from the paper wallet with the console (help > debug window > console) and enter
importprivkey <yourprivatekey> "label of address"

The optional "label of address" is just a description for you and not visible for anyone else.
After entering the importprivkey command, the wallet has to rescan the wallet for transactions, which may take a few hours depending on your system. After that, your address is fully spendable from within your wallet.
If you want to import multiple private keys, you can disable the rescan option until you entered all private keys with an additional argument. For example, to import 3 private keys you can use 2 times "false" to skip rescan and on the last import "true":
importprivkey <yourprivatekey-1> "label of address 1" false
importprivkey <yourprivatekey-2> "label of address 2" false
importprivkey <yourprivatekey-3> "label of address 3" true

Beware: Ensure that you claim your Bitcoin (BTC) first, and only after successfully sent them to another address use key for claiming your Bitcoin Cash (BCH), because BTC is way more valuable than BCH and I don't know how safe Bitcoin ABC actually is.
This procedure is a bit cumbersome, because you need to download the whole blockchain. But you are not dependent of any third-party applications or websites and don't reveal your private keys to anyone online.
This method can also be applied to any other Bitcoin Fork, assuming that there is a QtWallet for that Fork available.
After claiming your coins I would suggest to never use the address again. Get a new Paper wallet address if you want to use one again.

getting bch out of my paper wallet


How do I make my own question as community?

Question: I know that how to make my own answer as community wiki. How do I make my own question as community wiki?
Comment: **You cannot.** Community-wiki questions are only manually set by diamond moderators under rare circumstances. CW questions are usually famous important questions with a very high degree of activity.
Answer:
How do I make my own question as community wiki?

From this post https://meta.stackexchange.com/a/11741
Since October 2010, there is no community wiki checkbox when asking a question
check this answer https://meta.stackexchange.com/a/67582

We removed that option globally from all questions.
If it really needs to be wiki, flag it for moderator attention, it was causing confusion and pain.


Real time PCR parameter CT

Question: When puting a real time PCR, parameter CT, which means threshold cycle, is used. What does it mean really? according to wikipedia "The number of cycles at which the fluorescence exceeds the threshold is called the threshold cycle (Ct)"
could anyone put it in conext?
Answer: Realtime PCR uses a fluorescent dye which binds to double-stranded DNA and thus allows to measure the growing amount of DNA by each cycle. The DNA added to the reaction also binds the fluorescent dye and makes some part of the fluorescent background. When the PCR reaction starts, it takes a while until enough DNA is synthesized to go over the background and to be able to reliable distinguish the signal from the noise. I think this becomes clearer, when you look at the image below (from the NIH):

The Ct is the point where the signal can be distinguished from the background when it enters the exponential grwoth phase. The no template control stays below this threshold.
Comment: and when you make the calibration curve does it really matter which range of dilutions you choose or does it have to be a logarithmic serie? besides, when you get your results for different CTs, which is the criteria when choosing the correct dilution?
Comment: If you know the concentration of your standard exactly, you could do only one reaction. However it is better to do at least a few dilutions to see if your dilutions are correct and to test if your standard is amplified linear (meaning 10x more standard gives an accordingly higher signal). I would always choose a dilution which is as close as possible to your gene of interest. I mostly avoided absolute quantifications if possible, since relative quantifications usually where sufficient for us.
Comment: what do you mean with " I would always choose a dilution which is as close as possible to your gene of interest."?
Comment: That I use the curve (when I make more than one) which is nearest to my sample of interest. This way you avoid to skew you calculation by non-linear amplifications.
Comment: and when i use the most diluted concentrations i often get fold changes really diverse when comparing to the more concentrated. Is there any criteria i could follow to discard those results?

Real time PCR parameter CT


always on wifi & data connection whenever it turned off it's automatically turn on

Question: In Micromax A104 phone have always turned on WiFi & data connection whenever It turn off it's turned on automatically..pls solve the problem.
Answer: Could you be more specific about when the auto-trigger happens?(Like,right after pressing or when using any app)
Nevertheless,there are certain possibilities:

Virus attack-(I recommend a hard reset or flashing a stock ROM)
An app might be auto-triggering the switch-(Find the app causing the issue)
The faulty Hardware or the drivers itself(Go for a fix or replacement from the company if you have it under warranty)


How do I install a french drain in a sunken concrete patio?

Question: Just bought a new home the back patio is sunken with no drain. I know I need to dig down and put a French drain out side of it. Where is the best place to penetrate the concrete and put a drain ie. Base of the wall, though the floor, ... ?
Comment: Water flows downhill.  The patio is already a few feet below yard level.  If you dig a passive drain out into the yard, it will have to go even deeper.  As pdd describes, that is likely to collect yard water and route it back to your patio, making things worse.  A dry well in the yard would need to be huge, and most of its water would come from the yard rather than the patio.  If your goal is to drain water from the patio, put a sump pit in the lowest spot and pump the collected water through a pipe that discharges onto the yard as far away from your house as practical.
Comment: Where is this and how much does it rain there? Does it collect water in any rain or just blowing rain? How much is the surface of the patio below the grade outside? After a lengthy heavy rain does water from the soil drain into the patio at the base of the retaining wall or elsewhere?
Comment: I see some dampness on the surface - I don't see pools, puddles or ponds. So perhaps you don't need to add a drain at all.
Comment: I appreciate the comments relating to whether or not I need to install it, but when i have to use my shopvac to prevent the accumulating water from flowing into my home i am certain i want to do this. That is why I asked for recommendation on HOW to install it. Thanks
Comment: Where do you want the water to drain to?  You need a way to get rid of it (like a sump pump that you pipe to somewhere else).
Comment: Just away from the house out into the backyard
Answer: I don't think that a French drain will benefit your situation unless the issue is surface water flowing over the top of the retaining wall. If that is the case, then it might help, but you would not want to connect a drain inside the sunken area to it as it could actually allow water to enter the lower area.
A French drain is simply a tench filled with gravel (may also include perforated pipe) that directs water away from one area to another area.
If you want to get water out of the sunken area, you want to add a drain and pipe it to a storm drainage system, or depending on ground drainage conditions, pipe it to a dry well.
The main issue when dealing with unwanted water is finding a place to put it. A French drain is a way to move it not a place to put it. I think you should make sure that you know where you are going to redirect the water to before going any further. As for how or where to add the drain itself, see @isherwood's answer.
Comment: As long as the French drain is deeper than the level of the slab it will work great when the water is removed by the drain there will be no water to push into the slab area.
Comment: If there's water pressure at patio level now it'll show itself. That's not a swimming pool, after all. :)
Answer: It really depends on what type of drain grate you want and what tools you have available to cut the hole. If you can rent a core drill that matches the drain grate hardware, you'll probably want to put it in the floor. It would be difficult to cut a hole in the wall tight against the floor (to allow complete drainage).
I'd find the lowest point in the floor, or as close to it as the drill allows if it's against the wall, and go there. You'll be able to excavate outside the wall and under the slab to that point fairly easily, I'd think.
Comment: Very doable, connecting the drain under the patio slab via the trench for the french drain will be difficult, but possible. The trench for the french drain will need to be big enough to do what is asked of it and that will allow the drain to be excavated under the retainer wall of the patio and the connection made. The OP may want to do a dry well (closed top with dirt) instead of a french drain (open top with gravel exposed) unless it is preferred. I think I have the terminology correct....


How can I convert an m4a to mov?

Question: I have a m4a audio file that I need to convert to a mov file. How can I do this?
Comment: mov is a video format, what exactly do you want to convert here?
Comment: Just out of curiosity: Why would you want to do that?
Comment: Exactly what I said. I have a m4a file that I want to make into a video file. Is there a tool that makes this easy? I suppose the video portion would be just a black image, but if the tool allows me to select what image is displayed while the audio plays, that would be better.
Comment: I'm doing it to upload my podcast audio file to YouTube to take advantage of auto-captioning for a deaf colleague who wants to subscribe.
Answer: This creates an x264-encoded mov file with image.png as the background:
ffmpeg -loop 1 -i image.png -i audio.m4a -c:a copy -c:v libx264 -crf 20 -pix_fmt yuv420p -shortest output.mov
You can use mp4 or mkv as the container by just changing the name of the output file.
-c:a copy disables re-encoding the audio.
-loop 1 loops the image infinitely so that it is not shown for just one frame. It also makes the video stream infinitely long, so -shortest is needed to finish encoding after the audio stream finishes. -shortest has to be after the input files in new versions of ffmpeg.
-crf (constant rate factor) can be from 0 (lossless) to 51 (lowest quality). If you remove -pix_fmt yuv420p, ffmpeg uses yuv444p, which is not supported by many video players.
You can use a black background by replacing -loop 1 -i image.png with -f lavfi -i color=c=black:s=1280x720. You can resize an image by adding an option like -filter:v '[in] scale=-1:720, pad=1280:720:640-iw/2 [out]'.
More information:

https://trac.ffmpeg.org/wiki/EncodeforYouTube
https://superuser.com/questions/98980
http://tdb0.wordpress.com/2012/03/10/how-to-upload-a-song-without-a-music-video-to-youtube/
Answer: Open the .m4a in QuickTime and export it as a .mov file.
Comment: Doesn't work. The Format menu only provides the option "Audio Only". I want an actual movie...I suppose the video portion would be just a black image.
Answer: You could use iMovie to create a movie just showing a black screen and using the audio file as the audio track.
Comment: Good idea. Any good set of instructions for how to do that?
Answer: This can be accomplished with VLC.
Please refer to the following transcoding instructions.
Answer: Flip for Mac easily opened, converted and saved the file to .MOV

How can I convert an m4a to mov?


Does a sitemap for a blog/posts list simply contain all paths of the blog?

Question: I have a blog, and I am trying to index the blog posts in a manner quite like SO does. Would this sitemap.xml file act as basically a list and contain all of my blog URLs, or would I have to do something else?
Comment: A short answer is yes, though there's other information contained in sitemaps.  However, sitemaps are really a thing of the past and while many apps create them, Google puts a much higher focus on discovering pages via internal links.  For more information on sitemaps being outdated read https://webmasters.stackexchange.com/questions/4803/the-sitemap-paradox.  You'll be better off spending your time working on your internal links.
Comment: @Trebor thanks for the information!
Comment: What do you mean index the blog posts in a manner quite like SO does?
Comment: XML sitemaps have almost nothing to do with SEO. They don't help your pages rank better and they rarely get search engines to index pages they wouldn't index anyway. At best sitemaps get search engine crawlers to crawl new pages quickly and give you extra stats in webmaster tools and search console. See [The Sitemap Paradox](/questions/4803/the-sitemap-paradox)
Comment: If you want to have all your pages indexed, you need to improve your information architecture.  In other words every page should have links to and from several other pages. That is a big part of why this page has the list of "related" questions .
Answer: If you're just running a blog, you really only need an RSS feed. You can go ahead and submit that under the sitemaps tab in Search Console.
You don't need a sitemap unless you've got like 10s of thousands of pages and/or you're an e-commerce site. Most WordPress SEO plugins gen them automatically, so it's not much to provide it just in case.


Whipped cream without a mixer?

Question: Is it possible to make whipped cream without a power mixer? How? Can it be made with a stick blender?
Comment: I once tried with a power drill and a fork. Predictable results ensued - none of them being whipped cream...
Answer: Whipped cream was made for centuries before the mixer was invented. :)
You can do it with simply a balloon whisk. Things that may help though:

Very cold cream (not freezing)
Very cold bowl and whisk (put them in the freezer for 20 minutes prior to using)
Copper bowl

The process is simply to start slow until you see bubbles form, then speed up until you see the whisk begin to leave trails in the cream, then go full speed ahead until just before it starts to look soft and billowy. At this point you can add your sugar and continue whipping until thickens and firms up to form soft peaks.
Advice: Buy a hand-mixer at least! :)
Update - Yes you can whip it with a stick blender. I would be careful to avoid over- whipping with this method though. It might be easy to over-do it, and you'll start to make butter.
Comment: If you can't whip cream by hand you need to get fit! Seriously, it's not hard. Use a plastic container or jar and shake it for about 30 seconds. Don't try and do too much at once, say 50ml in a 250ml pottle. It has a much smoother texture this way, nicer than using any type of machine or siphon etc
Comment: Agreed, a cheap hand mixer costs around $15 CAD where I live. I think it's a cost that's well worth it, because hand mixing whipped cream is no fun, trust me, my hand almost fell off ;-)
Comment: @Nathan Koop: not to mention egg whites.
Comment: A copper bowl won't help with cream. It helps with egg whites, because copper ions bind to the proteins in egg white. The foam in cream is fat-based, not protein-based, and copper ions don't do anything there.
Answer: Put cream in a small plastic bag. Fill with air, twist to close. Shake.
Comment: I've never heard this one. How long does it take?
Comment: 1 minute maybe.
Answer: (responding to the update)
Yes, it can be made with a stick blender, I had a roommate who used to do it all the time.
He had a tall, narrow container, not that that much wider than the paddle on the blender, and he'd just stick the blender in, move it around a bit, and it'd be done pretty quickly.
(it's been 10+ years, so I don't remember the exact time.)
Come to think of it ... I can't remember him using that blender for anything other than whipped cream.
Answer: I've made it once by hand, with a whisk.  Like others, I had a sore wrist afterwards.
I do it all the time with a cheap stick blender because I'm lazy.   I especially like it for making a small amount.  I try to use a bowl which is about as wide as it is deep - deep enough to keep the cream from spilling, wide enough to move the stick blender around.
The problem I've found with using the stick blender is that once the cream starts to thicken, you have to be extra-careful to stir the cream around.  The blender will happily give you a dollop of whipped cream in the middle of a bowl of mostly runny stuff.  So every few seconds I shake off the cream that's stuck to the blender and stir the whole bowl a bit.
Comment: I have never had problems by using a whisk. Of course, I use a proper whisk (classic baloon shape, lots of bendy wires) and a half-spherical bowl. "Designer" whisks in strange shapes or stiff whisks with plastic "wires" are next to unusable for whipping.
Answer: Another option is to put the cream in a well-sealed jar (i.e. a mason jar) and shake it up and down into it reaches the desired consistency. There is a risk of over-shaking and ending up with fresh butter, but if you're paying attention you should be safe. It takes a few minutes and some arm strength, but it's not too bad.
Comment: Did it this way a couple weeks ago when I couldn't find a whisk. Surprised how easy it was. With good cream, it goes pretty quick.
Answer: It is possible with a whisk or fork, but your arm might fall off before it thickens up :)
Using a cold bowl and utensils (put it in freezer for a little while first) will help.
Answer: Do you have a food processor?  Whipping cream in my trusty Cuisinart is easy-peasy.  Put on the regular blade, pour in some cold heavy cream, turn it on for 20-30 seconds, et voila!
Answer: You can use a pressurized nitrous oxide dispenser. They're a little pricey for casual home use, though.
Answer: Alternatively, you can use a whip cream siphon.
Answer: Coincidentally, I saw this video a couple weeks ago that altered my world: you can make it in a cocktail shaker, using the spring from a bar strainer: https://www.youtube.com/watch?v=P5t3hZfMQiU
Answer: I saw it done on a program called "New Scandinavian Cooking! The Swedish chef made whipped cream and fresh strawberries on top of a glazier by placing whipping cream and sugar in a zip lock bag blowing air into the bag then sealing it then after shaking and squishing the bag for a few minutes...Voila" whipped cream!!!
Answer: I add powdered sugar and vanilla extract to my homemade whipped cream.
The starch within the granulated sugar stiffens the cream to "stand alone" and also the granulated sugar is ok enough to prevent the cream from feeling "grainy".
Some cooks use a small little bit of nonflavoured gelatin to assist the cream hold its form for a extended period. However I do not just like the style it imparts to the cream. I take advantage of one tablespoon of sugar and a couple of teaspoons vanilla per cup of "Heavy Whipping Cream". I use "Extra significant Cream" since it contains more solids and whips up thicker.

Whipped cream without a mixer?


When should I use an existing field?

Question: While adding new fields to a content type, When should I resue an existing field? for example if I need an image field for my content type is it always a good idea to re-use an existing image field?
Comment: if it's going to be used in the same way, accessible to the same users/roles, be themed the same way, etc, then yes, it will be much easier to maintain if you reuse the same field.
Comment: but if an image is going to be, for example, a user photo in one content type, but a thumbnail of a product image in another, then no, create different fields.
Comment: Related: http://drupal.stackexchange.com/questions/16718/fields-scalability/16733, http://drupal.stackexchange.com/questions/22692/using-existing-term-reference-field-vs-creating-new-ones/22694#22694
Comment: @Jimajamma Are you sure about the second comment? I think it can be configured in display settings of content type.
Comment: sure, it can be displayed anyway you want it, my comment is to the name of the field.  eg, field_avatar being used as the profile image of a user in one content type being overloaded as a product thumbnail in another type just is confusing from a naming perspective.
Answer: Consider the benefits and drawbacks of reusing fields:

Performance: There's a slight performance gain from reusing fields. However, for most sites with moderate numbers of fields, it's a negligible difference.
Maintainability: In theory, if you re-use the same field for the same purpose on multiple content types, then if you decide to change its functionality later, you only have to change it in one place. Similarly, if you want to theme it the same way across entities, you only have to use a single selector. In practice, this rarely happens, and more often the converse is true- you've used the same field in multiple places, and then realize that they actually need to behave differently.
Setup: Obviously, it takes less time to re-add an existing field than to add a new one.
Portability: If you export fields with Features, it's best to not reuse them between entities unless absolutely necessary. Technically, there's nothing wrong with reusing fields (since you can export field bases and field instances separately), but in practice it tends to just lead to confusion and circular dependencies. If you choose not to reuse fields, then you have the luxury of being able to prefix them with the content type / bundle they are attached to, e.g. "field_article_image", "field_page_taxonomy", etc..., which eases portability and maintenance.

In case it's not clear from my tone there, my preference is to never reuse fields unless it's totally, completely, 100% clear that they really are, and forever will be, used for the same purpose.
Comment: Agreed.  Also if you have different field settings say one image has only 1 while the other can use unlimited, if you change the field it changes all instances of it.

When should I use an existing field?


Chrome extension to set password

Question: Is there any Chrome extension which give you this ability to set password for Chrome? Such that just by entering the password you have access to that browser?
Comment: If you enter the password incorrectly do you want the browser to be non-functional or just limited functionality (ie won't remember/suggest website passwords)?
Answer: You can use ChromePW.

asks for a password when you open Chrome
you can lock it manually by right clicking and clicking ChromePW
if you press anything inside the Chrome window while the password box is open, then Chrome automatically closes
if the password is wrong more than a user-defined limit, Chrome will automatically close
security mode: if you try to open any other program (such as Task Manager), Chrome will automatically close (so it can't be bypassed; optional)

The settings you can change:

The password box:
Answer: You can use ChromePW
Either way you can also create multiple profiles in chrome if you dont want other users to know about the data in you account. and also use ChromePW there again. So it would be just like having multiple accounts in your PC and asking each user to signin using his password.

Chrome extension to set password


Which relay should I use to control the power from mains?

Question: I was making a home automation project in which I want to control appliances like a fan and a bulb through voice commands with the help of an arduino uno and a relay but I am confused which relay to use. Please tell me the specifications of a 4 channel relay fit for this project.
Comment: @Andy yes I want to control mains powered fan and light but first I will test the circuit with some leds and a dc motor
Comment: Do you want to control a **mains** powered fan and light? Please let us know. (For educational experiments something battery powered would be much safer.)
Answer: There are two factors you need to consider when choosing a relay:

Can it power the devices I want it to power without the contacts melting?
Can I control it?

The first one is simple enough. Find out the current requirements for each of the devices and add them together. Make sure that the relay is capable of switching at least that much at the AC voltage of your country's mains supply.  If in doubt go slightly higher.
For the second point you need to consider the interfacing circuitry and what DC power supply you are using in your system. For instance, if you have a 12V power supply for the Arduino you might consider a 12V coil relay and use the 12V power as the switching power. If you are running from 9V then you might consider a 5V relay and use the Arduino's regulated 5V pin as the switching power source. Either way you need a driving circuit. That could be as simple as an NPN transistor, two resistors, and a diode (the circuit can be found throughout the web if you Google "Arduino Relay"), or more complex involving an opto-isolator.
The simplest solution is to find an all-in-one module - a relay with driver circuit all as a single product. There are many of these around directly targeted at the Arduino, and most are the slightly more complex (and thus better) opto-isolator driving circuit. You still have to consider the same two points - switching capacity and coil voltage - but you don't then need to worry about making your own driving circuit for them.
Comment: Your 2 factors omit the most important issues - is it safe and do I have the knowledge to work with potentially lethal mains power.
Comment: Well, yes there are those factors as well, however Natural Selection is no bad thing...
Comment: @Majenko will the power to be supplied to arduino depend on the power requirements of the appliances to be controlled. I guess it would be best if I will be able to control the relay with arduino's 5 V supply.
Comment: @Jasmeetsingh No, the power provided to the Arduino has nothing at all to do with the devices being controlled.
Comment: @Majenko So if I use 9 V supply for the arduino is there any chance that the board will malfunction or get hot?
Comment: @Jasmeetsingh Possible - it depends what you have connected to the Arduino. 9V is within the specifications of the board, so chances are it will be fine, but I am not psychic and don't know what you are thinking of connecting to your Arduino.
Answer: In the US there is a set of products - plug-in modules - collectively known as X10, which uses signals sent over the house wiring to control devices elsewhere in the house. If they are available where you are, this is the safest way to control mains-powered devices with an Arduino because the Arduino needs no connection to the house wiring.
The Wireless Transceiver module receive X10 commands over RF and transmit them onto the power wiring. Using this and a small RF transmitter known here as "X10 Firecracker CM17A", your Arduino can be completely isolated from the house wiring, sending its control commands over the air instead. Amazon shows both products on this page; the CM17A (which you use by removing its circuit board from the plastic package), and the RF control module, of which you only need one. The transceiver module can directly control one fan or light; for additional devices you'd use any other, non-RF (read "less expensive") X10 module, which will "hear" whatever the transceiver module sends.
There is an Arduino library already written for X10 communication.


How can I access data from my Microsoft SQL Server 2000 on the client side?

Question: Right now I have Microsoft SQL Server ready configured, I want to use it for accessing database to more than one computer in a LAN. How should I go with it?
Answer: Not quite sure what you mean here but there are several options for accessing data in a database.
You can write a program in a language such as C# which uses ADO.NET to access the database. You can also use excel to get data from the database. SQL Server will support having more than one client so having multiple computers accessing it will not cause any problems.
If you give us a bit more infomration about what you are trying to do we might be able to help you out a little more.
Answer: You could install the SQL Server 2000 client tools from the same installation medium. That will give client computers access to the SQL Server Enterprise Manager and Query Analyzer.
Connect to your database using your server's name and your credentials (Security/Login).
Answer: Open corresponding port on the server firewall if any.
For basic tasks you can setup an ODBC dsn the get the datas.
Answer: Set up an ODBC connection on the client computers then use an application (e.g access or a custom written app) to connect to the database.


Do fighter jets use elevators as ailerons?

Question: I saw jets in game using elevators to roll right and left, but I never saw them doing in real life. I was wondering if fighter jets actually use elevator to roll like they do in game.
Comment: Jet fighters was invented at the end of WW2 so whatever you take from below as an answer, prepend them with a "Some of them".
Comment: Related: The [moment of a force](https://en.wikipedia.org/wiki/Torque) (the principle of the lever) and the notion of torque.
Answer: Yes.  The airplane's flight control computer can command a roll using all primary and secondary control surfaces, including differential actuation of the tailplane as Blue Angels #6 demonstrates during a preflight check.
Comment: Thank you! Now I found an answer for a question that I had for 2 years!
Answer: Yes that exists, the combined elevator/ailerons are called elevons. Particularly delta wing aircraft have them, because the space at the trailing edge of the wing is at a premium. The F-117 had elevons as well, as did Concorde.
Image source
Swing wing designs use elevons as well:

the F-14 Tomcat rolled through elevon and spoiler deflection.
This incident report mentions the elevon of the Panavia Tornado being damaged from a panel coming off.
Comment: @yshavit As far as I know, a stabilator is a control surface, usually located in the tail, that serves as both horizontal STABILizer and elevATOR, with no reference to the ailerons. :-)
Comment: You may want to add that when the elevon is on the tail (as the OP is asking about), it's typically called a stabilator. At least, that's my understanding.
Comment: Don't forget to mention swing wing designs: They use the horizontal tail for roll control as well.
Comment: @PeterKämpf Added.
Answer: Yes, high performance aircraft prior to the F-15/F-16 era (1970) or so, had a real problem in that attempting to roll the aircraft using ailerons, when at higher angle of attack(AOA) would, because of Adverse Yaw, produce a yaw in the opposite direction, (Stick to the left would produce right Yaw), which, because of the wing sweep, would create a roll opposite the intended direction. This was the cause of many aircraft accidents. The F-100 for example was infamous for something called the Sabre-Dance, where a pilot, by attempting to roll the aircraft using ailerons at high AOA on short final for landing, would induce a roll in the opposite direction, and put the aircraft out of control at very low altitude. The F-4 also had this problem, although by the mid 60s, it was understood well enough that F-4 pilots were trained to use the rudder to roll the aircraft at higher AOA. Instructors, training new pilots, were themselves trained to emphasize this flight characteristic, and, whenever at high AOA, to keep our knees in the back seat right up against the control stick to inhibit new pilots from introducing any aileron.
Before Fly-By-Wire was introduced, this tendency was addressed by having the stabilator, (Horizonal stabilizer and elevator), surface be differentially controllable, and mechanize it so that the fore and aft position of the control stick controlled the degree to which left/right deflection of the control stick would cause aileron deflection vs. differential stabilator deflection.  At low AOA (where control stick was forward), left right motion caused only aileron deflection. At very high AOA (where control stick was aft), left/right deflection would cause mostly differential stabilator. ( I think the first aircraft to use this technique was F-15, where it was implemented using mechanical linkages in the flight controls). Later of course, once Fly By Wire (FBW) was introduced, this was all done by the computer, and it was determined directly from measured AOA, and not just from stick position.
NOTE. The term elevon, is NOT relevant to the horizontal control surface (or surfaces) mounted at the tail of a conventional aircraft design that has a wing AND a horizontal tail. It is only used to describe the horizontal control surfaces at the training edge of the WING on a delta wing aircraft such as the F-102, F-106, Avro Vulcan, Eurofighter Typhoon, Concorde, Saab Draken/Viggen, etc.
The horizontal control surface (or surfaces) mounted at the tail of a conventional aircraft design are referred to as Stabilators, as they are completely movable without an embedded elevator Control surface, and therefore combine the functions of both a horizontal stabilizer and an elevator.
Answer: F-14 does this.  It's referred to as a "rolling tail."
In the case of the F-14 this was a solution to dynamics produced by variable wing sweep:

The tail control surfaces on F-14s are known as "rolling tails", in that the aircraft does not have ailerons on the wings to control roll. Roll control is instead provided at low speeds by wing-mounted spoilers and at high speeds by differential horizontal stabilizer deflection.

Here's a frame from the first Top Gun movie showing a real F-14 beginning a hard roll to the right.  The differential deflection of the horizontal stabilizers easy to see:
Answer: Yep! Not all of them do, but a good many of them. Off the top of my head I can think of the F-16, F/A-18, F-22, and F-35. They're referred to as elevons.
Comment: No they're not. The term Elevon only applies to the horizontal control surfaces at the training edge of the WING on a delta wing aircraft such as the F-102, F-106, Avro Vulcan, Eurofighter Typhoon, Concorde, Saab Draken/Viggen, etc. The horizontal control surfaces mounted at the tail of a conventional aircraft design that has a wing AND a horizontal tail are referred to as Stabilators.
Comment: From https://en.wikipedia.org/wiki/Elevon#:~:text=Elevons%20or%20tailerons%20are%20aircraft,aircraft%20such%20as%20flying%20wings. "An elevon that is not part of the main wing, but instead is a separate tail surface, is a stabilator (but stabilators are also used for pitch control only, with no roll function, as on the Piper Cherokee series of aircraft). The word "elevon" is a portmanteau of elevator and aileron."


Insoluble salts and Gibbs free energy

Question: Is it true that according to gibbs free energy equation, insoluble salts such as AgCl don't dissolve because the process would be too endothermic? The right side of the equation, TΔS, would have to be positive because entropy increases when salts dissolve, which means that ΔH would have to be high enough to make the equation positive. Is this correct?
Comment: @ChristopherMarley aren't those numbers the standard enthalpy of formation of AgCl from the elements in their standard states, and the standard entropy of AgCl? Not related to solubility?
Comment: G = H - TS. Let G = 0. It is known empirically that H is -127 and S is .0963, therefore T must be -1318.8 K. This means the reaction occurs at all temperatures, and therefore insoluble salts must not dissolve for some other reason. Correct me if I'm wrong, but that's my understanding of it.
Comment: It is incorrect to say that "entropy increases when salts dissolve" as a general truth. That is sometimes correct, but it can also happen that the solvent becomes more ordered in order to create a solvation shell, for example, which can overcome the gain in entropy of breaking up the salt lattice, so the $\Delta S$ is negative. Such salts are only soluble if the $\Delta H$ is negative and greater in magnitude than the positive $-T\Delta S$ term.
Answer: Yes, this is correct. Assuming that you are talking about solubility in water, it is discussed by JF Liebman, Structural Chemistry, 15, 165 (2004) which needs a subscription to read in full, but much of the key information is given on the first couple of pages which are available as a preview. The relevant thermodynamic quantities (in kJ mol$^{-1}$) for dissolution of one mole in water are given as a table, with AgCl compared with NaCl and KCl:

$$ \begin{array}{cccc}  & \Delta H & \Delta G & T\Delta S \\ \hline \text{NaCl} & +4 & -9 & +13 \\ \text{KCl} & +17 & -5 & +22 \\ \text{AgCl} & +45 & +37 & +8 \end{array} $$

The author got the original data from NBS Tables of Chemical Thermodynamic Properties.
All the entropy terms are favourable.
All the enthalpy terms are unfavourable, but the AgCl has a much more unfavourable enthalpy of solution than the alkali metal chlorides, and the
entropy cannot compensate for this. The Ag$^+$ ion is poorly hydrated in solution
compared with Na$^+$ and K$^+$.

Insoluble salts and Gibbs free energy


How to dress sushi to better enhance all its flavours?

Question: I would like to know what is the better way to dress sushi and sashimi. What I am looking for is how it was thought to be eaten and what are the ways a sushi piece is supposed to be dressed with soy sauce and wasabi to obtain a balanced taste!
Comment: I don't think you'll find any big-t truth exists to this quest. Might find some answers when *Jiro Dreams of Sushi* is released ;-)
Comment: If that is the case, why do many Sushi restaurants give you a little tray with wasabi and ginger? Am I supposed to hand that back to the chef and ask him to put a little dab under the topping for me? I don't think so.
Comment: From what I understand, wasabi is meant to be put on by the chef - a little dab under the topping but above the rice, to hold it in place.
Comment: @djangodude Presumably because it's done one way in high-end sushi bars in Japan and quite another for American audiences.
Comment: That was not my personal experience when I visited Japan, but I'm willing to accept the conclusion that there are considerable variations in how sushi is prepared and eaten in Japan and around the world (like pizza, hamburgers, burritos, and many other foods whose popularity has expanded well beyond the borders of their original/traditional locales).
Answer: I remain extremely skeptical that there is a right or wrong way to dress, pick up, eat, or otherwise deal with sushi. A Google search for "is there a right way to eat sushi" turns up hundreds of pages, many with contradictory information.
If there is a "right" way, it's most certainly dictated by the locale or restaurant you're in or the people you're with. My advice is to do whatever you want, particularly if you're paying for the meal. If you're a guest, follow the lead of your hosts. But don't sweat it. Enjoy it!

UPDATE since the original question has been edited...

what is the better way to dress sushi and sashimi.

"Better" is still difficult to define for everyone, and will vary by each person's taste. Something that "enhances" flavors for me may be completely unacceptable to you, and vice-versa. There's no accounting for taste! But since you made an effort to clarify your question, I am updating my answer accordingly.

Sometimes the "better" dressing is none at all. This is particularly true for Unagi or others that have some kind of sauce already applied (though I know some people who dip Unagi in soy sauce and claim it is great). I have a daughter with soy allergy, so she cannot use soy sauce at all and doesn't like wasabi. She enjoys eating salmon and tuna nigiri pieces completely plain. I've tried it myself, and with good, fresh fish it is really good.
I have heard of people dipping the pickled ginger in the soy sauce and using that as a kind of "brush" to gently apply soy sauce to the topping. That may be "better" if you are adept with chopsticks and enjoy pickled ginger along with soy.
Some people dip only the topping into the soy sauce, to avoid getting the rice saturated. This is a little easier to do if you use your fingers to pick up the sushi pieces (and according to some accounts this is perfectly acceptable for sushi) (but not sashimi).
Some people mix wasabi (sometimes, copious amounts) in with the soy sauce and dip the sushi into that mixture. Some suggest that soy + wasabi should be reserved for sashimi only.
Comment: Well, thanks. But then again if I like ketchup, supposedly I could dip the sushi piece into it. That's wasn't my point really. I like soy sauce, but I don't drink it from the bottle. I wasn't looking for the "right" way as you say, but how to dress the piece in order to better enhance its flavours, instead of just tasting a chunk of wasabi or soy sauce.
Comment: Consider rephrasing the text and title of your question, then. "Proper" implies "correct" or "right", and the remainder of your question sounds like a complaint about how other people eat sushi.
Comment: Thank you so much for updating your answer. You gave me the tips I was looking for!
Answer: Soy sauce, wasabi and grated ginger.
If you are eating sashimi, you can mix a bit of wasabi and/or ginger with the soy sauce. If you are eating nigiris, the chef probably put wasabi in it, so you may not need to put more.
But remember that the point of eating sashimi and nigirizushi is to feel the taste and the texture of the fish and the rice. So be really gentle when dipping the fish, or you will kill all the taste. Only a touching one corner of the fish should be enough... and for the nigiri, don't touch with the rice, or it will get damp.


How do you handle change requests in Scrum?

Question: I am working on a project. My client has asked for a requirement that slightly deviates from the initial terms and conditions agreement. I think it's a change request. In Scrum, how do I handle a change request? Do I put the change request into the Product Backlog and then prioritize?
Answer: TL;DR
The original question was tagged Scrum, so my answer will focus on how Scrum expects routine and non-routine changes to be managed. In brief, Scrum embraces change, but encourages the Product Owner to plan refinements for future iterations whenever possible.
By treating refinements as new work, the framework encourages ongoing collaboration between the Scrum Team and stakeholders. It also encourages stakeholders to take responsibility for product planning in a less myopic way by making cost of delay and cost of planning disruption explicit parts of the value discussion. This prevents the rubric of "business value" from becoming a very heavy club for stakeholders to beat the Development Team with, and forces pro-and-con discussions of business value to the forefront of Product Backlog discussions rather than leaving them as hand-waving exercises where the squeakiest wheels will be given the highest priority regardless of cost to the project or the Development Team.
Change Management Options in Scrum
In Scrum, frequent-but-controlled change is baked into the framework's empirical control process. Change is expected over the life of a project, but the framework expects refinements to be made at iteration boundaries. An escape hatch for more profound changes to scope or strategic direction is also provided, but the costs for such changes are explicitly charged to the project.
Refinements
Scrum is an iterative methodology. Changes are expected, but the idea is that most changes represent small refinements to work that's come before. For example, "a requirement that slightly deviates from the initial terms and conditions" is a refinement of a previously-planned or -implemented feature, rather than some radical new direction for the product.
Refinements that don't jeopardize the current Sprint Goal are generally treated as new work to be planned for a future Sprint. Since the Development Team has already planned the work for the current Sprint, refinements are placed onto the Product Backlog to be estimated, prioritized, and planned the same way as any other work in Scrum. This is the very essence of iterative development!
This ensures that the overall value of the current Sprint Goal can still be delivered. During the Sprint Review, the Product Owner and customer can determine whether the delivered increment is good enough to keep as-is, or whether the potential value of the proposed refinement is worth allocating capacity to in future Sprints. The Product Owner can then prioritize the refinement accordingly.
Another benefit of this approach is that change within a Sprint is minimized. By encouraging changes at iteration boundaries, the framework leverages a predictable inspect-and-adapt cycle to provide routine inflection points to stakeholders. Stakeholders don't have to wait indefinitely for their changes to be considered, because they know exactly when the next Backlog Refinement and Sprint Review will be. It also gives the Product Owner the leverage to determine whether a changed requirement is really so urgent for the business that it can't wait for the next beat of a well-defined development cadence.
In many organizations, stakeholders substitute magic words like abracadabra with "business value" in order to push through disruptive changes without charging the cost to the project or fully weighing the potential cost of the change. Encouraging change at predictable inflection points ensures that the stakeholders bear some of the responsibility for planning and thoughtful change control, and this generally reflects a careful balance between flexibility and disruption.
Escape Hatch for Profound Change
Despite the foregoing, there are times when a change is either so urgent that it truly can't wait for the next iterative cycle. Scrum doesn't prevent such changes; it simply makes the cost of those changes explicit and visible to the stakeholders.
If there is a change that would invalidate the current Sprint Goal, or that can't wait until the next Sprint to be prioritized at the top of the Product Backlog, the Product Owner can cancel the current Sprint:

A Sprint can be cancelled before the Sprint time-box is over. Only the Product Owner has the authority to cancel the Sprint, although he or she may do so under influence from the stakeholders, the Development Team, or the Scrum Master.
A Sprint would be cancelled if the Sprint Goal becomes obsolete. This might occur if the company changes direction or if market or technology conditions change. In general, a Sprint should be cancelled if it no longer makes sense given the circumstances. But, due to the short duration of Sprints, cancellation rarely makes sense.
When a Sprint is cancelled, any completed and "Done" Product Backlog items are reviewed. If part of the work is potentially releasable, the Product Owner typically accepts it. All incomplete Product Backlog Items are re-estimated and put back on the Product Backlog. The work done on them depreciates quickly and must be frequently re-estimated.
Sprint cancellations consume resources, since everyone regroups in another Sprint Planning to start another Sprint. Sprint cancellations are often traumatic to the Scrum Team, and are very uncommon.

The last part is especially important. It forces the project's stakeholders to treat disruptive change as a visible cost to the project rather than wishing the costs into the cornfield, or hand-waving the disruption to the Development Team's current increment of work. It forces the Product Owner to ask the business whether the cost of disruption outweighs the cost of delay, and to consider potential impacts to the agile release plan and the lead time of other items on the Product Backlog.
By making these considerations visible, the framework prevents hidden work and hidden costs from creating drag on the project. It also fosters collaboration and communication with stakeholders, and often leads to tighter and more effective feedback loops for each iteration.
Since only the Product Owner can actually cancel the Sprint, it ensures that such drastic changes are controlled while still allowing them to be made when truly necessary. In other words, even drastic changes can be made within the Scrum framework, provided that the costs are visibly charged against the project and any changes to the project plan are visible to everyone.
CodeGnome's Law of Transparency says "No invisible work, ever!" This framework feature enforces that, without preventing the business from pivoting when required. It provides rigor without inflexibility, and that's what makes it agile.
Answer: Short answer is: yes. Backlogs are assumed to be emergent and are expected to change and be re-prioritized often.
Answer: Although Agile is setup to expect and to handle change, there isn't a great deal of detail in Agile frameworks about how to handle contract changes.
The assumption is that in an Agile delivery some mechanism will be put in place to deal with significant changes (i.e. change requests). For example, some organisations will work using 'time & materials' where any changes are naturally covered by the cost of the extra work. Other organisations may use contracts that are built to work with Agile, where scope is designed to be flexible.
As such, I'm afraid the answer to your question isn't clearly defined as it will depend on the contractual agreement you have.
Comment: I think this is a good answer, but I suspect that the OP really meant some sort of up-front planning document (incorporated into the client contract or not), rather than the contracting process itself. I agree that the use of "terms and conditions" in the OP was confusing, but would say that a contract-management question is simply off-topic if it turns out that's what was really meant.
Comment: I based my answer on when I worked at a consultancy that used a mixture of traditional project management and Scrum. There were all sorts of different approaches to handling change requests that varied from customer to customer. When using time & materials we usually just added a CR to the product backlog. However, on fixed price contracts we sometimes kept CRs out of the backlog and billed them in a different way. I guess my point is I find it hard to see how you separate out the contractual from the process. CRs are inherently a contractual thing.
Answer: In my experience it is best to keep the current sprint backlog relatively static, but if the new requirement cannot wait until the next sprint, I believe the only sensible way to deal with an additional requirement is to trade it with another similar sized requirement.
If you allow things to be added you run the risk of the whole process of scrums and/or sprints running into disrepair longer term.
Answer: We allocate 10% as a buffer time to accommodate any urgent requests or change requests that come after the start of the sprint. Obviously it would mean re estimation and realignment of priorities. Anything more than 10% we move out other tasks with similar estimates.
I know it defeats the purpose of having the sprint if you resuffle the tasks midway, but business is our priority and we can't compromise business at the cost of methodology.
Answer: One of the main things each Scrum Master deals with is protecting the Team from incoming work to the active Sprint. As a Scrum Master, your role is to help your Team stay focused on the active Sprint and protect them from incoming requests that might put that focus at risk.
Knowing how to deal with those incoming requests from the beginning will be a huge help for you. I created a short 2 min video that shows how to deal with that scenario: Scrum Master Tips: How to handle requests coming to the Scrum Master directly.
Comment: I think this answer would be better if it had the key points of the video in your answer. External links go stale, videos get taken down, etc
Answer: In my experience it depends on a lot factors, if the task is out of scope, it will be considered when all tasks and items on the backlog has been cleared. If it is part of scope and was not considered before then it can be added on the backlog and be done in the next sprint.
Answer: "I just started the car.  But, as soon as I did so, I wished that the engine should be located in the back.  Is this a problem?"


Identifying and crimping 2-pin connector

Question: What are these plastic connectors? They're female and male counterparts. One has male pins and the other has female metal square-holed pin receptacles. What are these called? Here's a side view and into-pin view. The wires are 20 AWG. They're for connecting to the solar panel and DC motor of a solar-powered attic fan. I want to make another pair. How do I crimp the wires into the pins and insert them into the connectors? What is the specific crimper called?
Comment: Upvote for including photos and making this a quality question.  I'd expect you will get quality answers from this.  I have seen these inside microwave ovens, but nowhere else.  Welcome to Home Improvement.  Take the tour at https://diy.stackexchange.com/Tour to get the most out of this site.
Comment: @SDsolar , +1, the tour was helpful and it just gave me an achievement.
Answer: I have always referred to them as "Molex Connectors".  They are assembled by crimping the individual pins and inserting them into the plastic connector. The pins are crimped by a special tool. Using a generic crimping tool will result in a poor connection. A small tube shaped tool is used to remove the pins from the plastic connector. Unless you plan on doing many of these connections the cost of the tools makes it an expensive repair. A less expensive solution is to purchase the  connectors with a pigtail (a short section of wire factory installed). Then make the connection with a generic crimped connector available at most automotive parts stores.
Comment: The easiest solution might be to find a 2 pin 20gauge male and female connectors. Cut off both your factory connectors. Then splice them to your wires. You can solder or use generic butt connectors available at an auto parts supplier.
Comment: I always soldered instead of crimping. No special tool needed.
Comment: +1, thanks for pointing me in the right direction & for pigtails advice. Do you mean to splice & solder pigtail's tail end to the source & then plug the pigtail's factory-installed connector (head end) to the one in my pic? Molex is a company/brand. What are the generic versions (if any) called? From your answer, I found everything except the pigtail that comes with the connector. Do you know what the pigtail is called specifically? If you have time, please see the end of my answer that has the other components' names, if that narrows down the search terms (not trying to hijack your answer).
Answer: As mikes answered, these connectors are a type of Molex connector. (Or they may be their generic equivalents, if any.) Molex is a company/brand. It has several types of 2-pin connectors. The connectors in my OP pictures are part of either Molex's "Mini-Fit Jr." trademark of power connectors or a generic equivalent (if any; I don't know whether generics are permitted to be made).
Molex's Mini-Fit Jr. diagrams considers the plastic connector that gets partially enclosed in its counterpart connector when mated as the receptacle, perhaps because the receptacle permanently houses the socket (female) terminals. Molex considers the plastic connector that partially encloses its counterpart connector when mated as the plug, perhaps because the plug permanently houses the pin (male) terminals.
I don't know what the connectors in my OP question are called if unbranded, so I'd also appreciate an answer that can give unbranded but specific names or search-friendlier branded names. This question discusses the difficulty in web-searching for Molex and generic or other-brand connectors, the shortcomings of related nomenclature, and the usefulness if the nomenclature were to have some basis in chamfered keying permutation, and it lists a few brands. In web searches, the Molex items can almost only be disambiguated by their manufacturer model numbers. Without first knowing the number or uniquely identifying unbranded terms, some trial-and-error options are image searches or searches on manufacturer or retailer sites with specific categories. Waytek has the category:
Terminals & Connectors  >  Multi-Pin Connectors  >  Mini Fit JR Connectors.
It's difficult to find these connectors on Molex's website even with the model numbers, because it gives overly-generalized reference pictures, sometimes with a different number of circuits (i.e. corresponding pins or wires), of the model's containing series. Waytek gives more specific pictures. (I'm not affiliated with any party, but this is how I best found the info in the absence of clearer nomenclature.) There are several models of Mini-Fit Jr. connectors. Going by Waytek's nomenclature, the items in my OP question appear to be the following or their generics (if any):
The plug is Molex 39-01-2021 Mini-Fit Jr. Connector, 2-Pin Panel Mount Plug.
The receptacle is Molex 39-01-2020 Mini-Fit Jr. Connector, 2-Pin Receptacle.
The pin terminal is Molex 39-00-0041 Mini-Fit Jr. Pin Terminal, 24-18 AWG.
The socket terminal is Molex 39-00-0039 Mini-Fit Jr. Socket Terminal, 24-18 AWG.
Their corresponding extraction tool is Molex 11-03-0044 Mini-Fit Jr. Extraction Tool.
The only crimp tool I found named by Waytek specifically for Mini-Fit Jr. is Molex 63819-0900 Mini-Fit Jr. Crimp Tool, which is expensive. Molex's corresponding Application Tooling Specification Sheet lists the aforementioned terminals' model numbers as compatible.
A cheaper crimper, named by Waytek but not specifically for Mini-Fit Jr., called the Molex 63811-1000 MLX Hand Crimping Tool, 24-14 AWG, applies to the desired gauges, but the corresponding Molex Application Tooling Specification Sheet doesn't specify the aforementioned terminals. But the "Application Tooling" section on the righthand side of Molex's product page lists some models of terminals that seem to have pins shaped similarly to the desired one. Also, the corresponding Amazon listing includes the phrase "For Mini-Fit Jr." in its title.


Are these SSH passwords of hacked servers?

Question: I have been seeing persistent SSH connection attempts on my computer from a familiar IP address. I got curious and decided to do some Googling on the IP address. Turns out that someone from Indonesia is publicly sharing a whole list of IP addresses of servers, some from Digital Ocean, with their SSH passwords. I am not sure whether these servers belong to that person, whether these are admin passwords and what is the purpose of the person sharing it publicly. But it does look shady since I am getting SSH login attempts from one of those IPs. Are these SSH passwords of hacked servers? Why is the person sharing it? What can be done about it?
Answer: I'm seeing the posted link and it seems to be an Indonesian facebook page, where the group writes IPs and credentials of different servers. I think so these servers don't belong to the group, but the group itself discovers them by sharing their credentials. I don't know what they do with them, but then the servers are most likely hacked for some purpose.
Similar attacks are performed by brute forcing an SSH connection through specific tool (Hydra, Medusa, ...), as you are seeing in your computer. So, it is very important to have a strong SSH password (alphanumerics>=10), to define a specific user for the SSH connection, and to disable the root/admin account for SSH logins. You can find a lot of posts on how to protect a SSH server:
http://www.tecmint.com/5-best-practices-to-secure-and-protect-ssh-server/
Unfortunately it's common to find out similar group of crackers (pay attention, not hacker), but it's the first time I see a clear fb page.
Comment: "it is very important to have a strong SSH password": or to disable password authentication altogether in SSH config and allow only public key authentication.
Comment: Or you can just use fail2ban and configure it to ban everybody who enters the pass wrong more than N times. I've configured it to drop all connections from the banned IP for a day or two and so far (3 years) I haven't had any problems. But using auth keys is also a very good idea, since most bots are mainly brute-forcing for a normal pass.


Where can I get statistics about illness relationships with vitamins and minerals deficiency?

Question: I would like to know where I can get a credible source of information about health.
I read a lot of information about what causing an illness a lot of information that somebody else claim its wrong, I am a computer scientist and I know how to get info from data, so I want a data set contains illnesses and and what is the diagnosis, or illness and what deficiencies in the Patients.
Answer: I think you are trying to search for diseases and their symptoms.
You can obtains such a data set from here.
Answer: Check Journals for Sports Medicine, and for Professional Athletics.
If you want a diagnosis app, check https://ada.com/, free for Android and Apple.
Another possibility is to search OpenClinicalTrials on PubMed . However, finding an article there that has also  results/datasets attached is possible but can be time consuming. These results are for doctors and epidemiologists.
Scroll down to "Associated data", then click on the link to clinicaltrials.gov. Example , click on "Study Results".


How to install a Windows desktop under Wine

Question: Once I have installed Linux and Wine, how can I get a Windows desktop (you know, a  relaxing view of green rolling hills and a bluer than blue sky) with Windows menus (if at all)?
Comment: You don't, Wine is not an emulator, you run Windows apps directly as if they were native. And the "green rolling hills" are WinXP only.
Answer: Run winecfg, then go to the graphics tab and activate Emulate a virtual desktop.
The details (like the background pic) can be set at win.ini file, in your .wine directory.
You'll have to get that background pic from somewhere. It is not included in Wine, but it can be found at several places online.
Answer: Wine stands for "Wine Is Not an Emulator", and you are asking for an emulator. Several options exist (such as Virtualbox, which is in the distro repos for at least the debian and arch branches).
You cannot install windows via wine and expect it to run properly. Instead, you need to virtualize a system, and install windows on that system. Virtualbox, Qemu, and VMware(non-free) are all options that may interest you.
Comment: -1 Wine is not an amulator, but that does not mean you can't run an emulator on it. Indeed, this is a standard feature.


Dew point variation in a day

Question: Is this true?
"If there are no weather front or severe weather systems, then the dew point within a single day is fairly constant, no matter how large the day/night temperature variation."
Comment: Where did you find that statement? reference? link?
Answer: From a review of weather observations, that statement is false.
Below are  the synoptic weather maps for Australia for 11 August 2015 and  12 August 2015. There are no weather fronts, or adverse weather in the western two-thirds of the continent.

Alice Springs (lat:-23.8, long: 133.89) is in the centre of the continent. It's weather observations for 11 August 2015 reveal the temperature ranged between $5.8$ $^oC$ and $26.0$ $^oC$ and the dew point  range was between $-18.8$ $^oC$ and $-2.5$ $^oC$.
Similarly for Darwin (lat: -12.42, long: 130.89), which is located on the coast in the sub tropics, in the central north of the country, the temperature range for 11 August 2015 was $19.7$ $^oC$ to $30.1$ $^oC$, while the dew point range was $15.4$ $^oC$ to $19.8$ $^oC$.
Perth (lat: -31.93, long: 115.98), on the southern western coast has a temperate Mediterranean climate. It's temperature range was $10.2$ $^oC$ to $17.6$ $^oC$ and the dew point range was $5.7$ $^oC$ to $11.7$ $^oC$.
Adelaide (lat: -34.95, long: 138.52), on the southern coast, in the centre region , also has a temperate climate and its temperature ranged from $7.6$ $^oC$ to $15.4$ $^oC$ and the dew point range was $-0.3$ $^oC$ to $8.5$ $^oC$.
Lastly, Brisbane (lat: -27.39, long: 153.13) which is on the east coast  had temperatures between $8.2$ $^oC$ and $21.9$ $^oC$ and the dew point varied between $6.9$ $^oC$ and $15.8$ $^oC$.
All these weather observations show significant variance in the dew point for these locations given the respective temperature ranges and the lack of weather fronts and adverse weather systems.
Answer: If you consider a closed system, this will be true, as dewpoint is related to the absolute moisture which is not a function of temperature.  However, as Fred's answer demonstrates, the atmosphere is not a closed system.  Even devoid of fronts and severe weather there are still pressure gradients which result in wind.  Wind advects moisture and so if there is wind the moisture (dew point) can change.
Furthermore if we consider surface fluxes that statement becomes even less true.  With no advection if we have vegetation or standing water on the surface we can increase the dew point just through evapotranspiration.

Dew point variation in a day


when parenting object to bone, the object changes position

Question: I have a robot, when parenting one object (upper arm)  with a specific bone, ctrl_P and selecting Bone, causes the object changes its position. I have no idea why. Can someone give me a clue? with the lower arm, there's no problem at all. I'm using Blender 2.69.
Answer: It was my mistake, the object was previously parented with another object, so, when re-parented the object with the bone, its position is now referenced with the position of the bone, forgetting the previous spatial reference with early parent object, so it cause re-positioning :-)


Can we have a user with the same powers/priviliges as root?

Question: I am confused on the following in linux.
Can I have a user to have the same permissions as the root. In Windows any user can be the administrator but I am not clear exactly about this on Linux.
It seems that root is the "magic" account with all permissions, but can I create a user that has exactly the same permissions?
E.g. if I am user jim in Linux can jim be root? I am not talking about sudo but being able to do anything the root does.
Comment: For the record, the Windows equivalent of the *nix `root` is actually `SYSTEM`.
Comment: It's no problem to have different usernames with uid 0 in the system. Use `useradd -o -u 0 rootz ...` e.g.. I've used that to have a root login with a different shell.
Comment: @ott:Could upgrade `jim` to be root?
Comment: The preferred way is `sudo`, so `jim` could execute specific or all commands as root.
Comment: @Jim You need to add more info in your post, what version of Linux are you running? Redhat, Ubuntu, etc.....
Comment: just set user id 0 for your user: http://pthree.org/2008/07/17/duplicate-uids-on-linux/
Comment: @ayvango That is a *horribly* bad and dangerous way to do it and should not be recommended to *anyone*. If you don't know what you're doing it's a very easy way to completely hose your system, and if you do know what you're doing you shouldn't need to be told.
Answer: Is possible but not recommended  create an account with the same privileges as root, by several factors.
Check Man adduser.
Comment: Why did you remove the example? Your post would be much better if it included not only a link to the manpage, but a practical example of how to achieve what the OP needs.
Answer: The preferred way to run commands with administrative privileges is sudo for CLI and gksu for GUI. Read up on visudo for info on how to configure access for users through these commands. If you're the only user on your system and not concerned about someone else using it and messing something up, it's possible to be able to execute commands as root without password for sudo.
You shouldn't run some applications as root, for example IRC. That's why there's sudo, and without it, commands are run as the current user by default to prevent unauthorized root access from application level.
Comment: `it's possible to be able to execute commands as root without password for sudo` How?
Comment: Check the `sudo` documentation on how to add `NOPASSWD` to your sudo user. **NOTE** this is not recommended because it makes it that much easier to make a horrible mistake.
Answer: Yes and no, at least "no" means you won't have it behave like I think you expect.
In UNIX, there's UID 0, b.k.a root, and everyone else. This is coded in the kernel, it's not something you can easily change.
Yes, you could have jim also be UID 0, but then that mixes things up. Remember that you don't store user names really anyplace, you store userids, and reverse map it through /etc/passwd (or other maps like LDAP) when needed. So, when jim does ls -l in his dir, he'll probably see his files owned by root. jim isn't another account, as much as an alias for root. This aliasing doesn't seem to be what you want.
This aliasing can be useful. FreeBSD has root with shell /bin/sh (which sucks for interactive use, but is statically linked and doesn't use /usr) and toor, also UID 0, using /bin/tcsh. If the system went to hell, you used root, which depended on fewer things. But for routine maintenance, you'd use toor, which had an easier to use shell. But this is an alias, not two separate accounts, and not what you want.


Bass line melodies

Question: Can a bassline act as the melody of a song or be the focal point over a melody in a song? Listen to the instrumental below for example. It sounds like the bass-guitar is the lead tune throughout the whole song with the exception of the riff that occurs every 8-bars. By the way what instrument is playing that riff to me it sounds like a guitar.
Comment: Try listening to some [Red Hot Chili Peppers](https://en.wikipedia.org/wiki/Blood_Sugar_Sex_Magik) for many examples of bass melodies.
Comment: Muse - Hysteria
Comment: Stop, collaborate, and listen... There are a ton of examples of a baseline being used, and reused.
Comment: [Of course it can](https://www.youtube.com/watch?v=l9bH6R3gj0I).
Comment: There is a huge amount of organ music where the pedal part plays the *cantus firmus* and the manuals embellish it.
Answer: It's almost like you answered your own question! Yes, a single line of music can act as both the "bass line" and the "melody".
The term "bass line" usually refers to the set of lowest sounding notes in a piece of music that has some form of harmony or counterpoint or other tonal structure. If there isn't much of a tonal structure, then that meaning has less meaning. Even when there is a tonal structure, the lowest sounding notes can be the focal point of the music. This is rare because our ears and hearing processes tend to hear the higher notes in the audible range more clearly, so melodies tend to be the highest sounding notes, or at least notes in the octaves above middle C, where our hearing really tends to focus. That said, there are contrapuntal pieces like Bach fugues and inventions where the themes (basically, "main melodies") are traded back and forth between the highest and lowest sounding notes (and middle notes, when three or more parts are written).
"Bass line" could also, or instead, refer to all the notes played by a bass guitar or some other instrument that is acting as a bass guitar. Since any instrument can play a melody, including a bass instrument, it's entirely possible for the "bass line" to also be the melody, regardless of whether the notes are the lowest sounding, highest sounding, or are intermixed with any harmony that may exist.
Answer: People don't normally call a bassline 'the melody' as such, because... it's a 'bassline'! Nevertheless, it's absolutely possible for a bassline to be a focal point of a tune, and it's a standard feature of funk, disco, and especially hip-hop genres, some reggae, dubstep.... and more.
Comment: I was immediately thinking of Rapper's Delight, probably one of the most famous bass lines of modern times (taken from Chic's *Good Times*). Or at least one of the most recognizable ones even by musical laymen. It stands right in the middle of half of the genres you listed.
Comment: @JörgWMittag yes... and of course there is at least a one-, if not two-way dialogue between many of these genres... and the form leaks into rock, e.g. Queen's 'Another one bites the dust'.
Comment: Perhaps Under Pressure counts as an example in some broader sense too, even though it's more like an ostinato.
Answer: It's hardly what one could (or would) call a melody. It's just a recurring pattern - an ostinato. But, I suppose, yes, in the absence of any other instrument, it's the 'lead'. Although to me, it's crying out for something else to go over it all, with a melody...
Sounds to me like a bass guitar going through a synth patch, or indeed, a synth itself.
Comment: The original song that the sample is from, 'Rise', puts plenty of stuff over it: https://www.youtube.com/watch?v=vltC-O7PDYQ
Answer: A bass can absolutely play the melody.  It's not "standard," but that doesn't mean an aspiring bassist can't do it.
Rush would be an excellent source of countless examples.

Bass line melodies