Does the operator $A^*A$ have a name?

Question: The self-adjoint operator $A^*A$ (for a generic linear operator $A$) is used in functional analysis, linear algebra, statistics, physics, and probably many other fields. I am curious if there is a standard way to refer to this operator? There's the Gramian of course, but that seems specifically to refer to a collection of finite-dimensional vectors. "Gram operator" seems natural to me, but Googling suggests that it's not widely used.
Comment: I have seen the notation $A^G=A^*A$ to emphasize this "Gramian" operation ... as an operator.
Comment: Gilbert Strang loves to emphasize the importance of $A^* A$ in linear algebra, and I don't recall him having a name for it.  (He also emphasizes $A^* C A$, where $C$ is symmetric positive definite.)
Answer: In the context of Quantum Mechanics the operaror a*a with the same characreristis of your given operator is called the Number operator (in the framework of creation and anihilation operators). The number in this case accounts for the number of particles in a given quantum state.

Does the operator $A^*A$ have a name?


Change to Art-Optimized Supersampling in Illustrator

Question: I was wondering if it's possible to change my viewing in Illustrator to art-optimized supersampling, instead of the type-optimized anti-aliasing that is default.
I'm not talking about the exporting of a file and changing the option there. I'm talking about viewing and working on artwork IN Illustrator. I know there is an option in Preferences > General to switch anti-aliasing on or off, but no option to change the type of anti-aliasing.
Answer: (No, there is no such option.)
Atleast as far as I can verify, the negative is very hard to prove. But this is hardly surprising as it would be much slower to work with.

Update to this question (17.07.2016)
It seems that I am wrong, you can indeed do this with a bit of fiddling. While it is not global you can still do the same thing by placing all your data inside a master layer (you can have layers in layers) that applies this effect. To do this:

Select the layer that contains all your artwork (click circle next to layer name)
Apply a rasterize effect with the art optimized aa option and 72 dpi resolution (for pixel preview)

As a bonus you could super sample some shapes while keeping for example text text optimized.


What will the result most likely be?

Question: So I watched Fight Club and now I have a social experiment. I am going to go in front of my neighborhood's local market(across from a large high school) while students are having their lunch and just start randomly pummeling punches after punches at myself and beat myself up really bad in front of everyone and see how they react. My only concern is if this is illegal what I'm doing, or if I will need permission from police and the school to do this first?
Comment: Maybe you need some help from social or medial  assistance...
Comment: What idea or hypothesis would your social experiment confirm or falsify ?
Answer: People in the nearby area would likely contact emergency services. As a matter of policy, emergency services would conclude that you are demonstrating behavior consistent with a person who is severely mentally ill. Because you have become a hazard to yourself, they would pursue emergency psychiatric care. This would involve being taken to a hospital or other facility, where you would undergo screening and a battery of tests. This process is usually no shorter than 72 hours, but can be significantly longer if medical officials believe that you a persistent hazard to yourself.

...in front of everyone and see how they react.

In horror. They just watched a person perform severe self-harm in a public setting. They would believe that you are mentally ill.

My only concern is if this is illegal...

Self-harm is not strictly illegal in all jurisdictions, but you would be taken into protective custody by police in most, if not all, jurisdictions.
I don't fully understand the philosophical nature of your question, since we have lots of instances of this sort of behavior being responded to in a fairly consistent fashion.
Answer: are you asking if you could actually be able to recruit Men like in the movie? , if yes , the result will be more likely to fail. without knowing what exactly influence/motivate those Men to start something like the fight club is impossible. more the place and time you picked is far from what you should be using , i think. in doing experiments you should be more careful on what are the variables you are considering . ex. in the movie it was night time, not too many people(Men) around outside the bar. the bar as i remembered was not that empty so you might wanna consider it was a weekend (just for assumptions). i would pick that time because the movie tackled topic against industrialism/commercialism/consumers (most likely against the day job and against routines) weekends would be a good choice to do so because people(Men) should be tired over the week and would want escapes. My point being is your first concern is not if its illegal to punch your own face in public but to start thinking and planning better.

What will the result most likely be?


Confusing Volumetrics

Question: I have a simple glass exture applied to this bulb and a circle inside with an emission texture on it w/ the strength about 30. How do I get this emission texture to fill the bulb?
Answer: Here is my node setup for a light bulb, I hope it helps. It worked well for my scene.
You can use this for the bulb only, if you want, or you can keep the emmission sphere, and use the glass settings.

Confusing Volumetrics


How to make softer biscotti?

Question: I made this biscotti recipe yesterday - Fruity Christmas Biscotti. It contains plain flour, baking powder, mixed spice, golden caster sugar and eggs. The recipe also calls for raisins, dried cherries and nuts which I substituted dried cranberries and white chocolate chips for.
I love the recipe but it was a bit hard - I know biscotti is supposed to be hard but is there any way I can make it chewier or softer? I'm really looking for an ingredient to add, or to change the quantity of something that is already in the recipe rather than storage suggestions like putting an apple in the box with the biscuits.
Answer: My kids love a similar recipe, but they also like them softer. What I do is reducing the second baking time by half.
Be aware that the shelf life of the biscotti is also reduced! ... Not a problem in my case since they don't survive more than two days ...
Edit
Some history:

Though modern biscotti are associated with the Tuscan region of Italy, the popular Italian cookie traces its origins to Roman times. The word biscotto derives from "bis," Latin for twice, and "coctum" or baked (which became "cotto," or cooked). The Roman biscotti were more about convenience food for travelers rather than a pleasurable treat for leisurely diners. Unleavened, finger-shaped wafers were baked first to cook them, then a second time to completely dry them out, making them durable for travel and nourishment for the long journeys—Pliny boasted that they would be edible for centuries. Biscotti were a staple of the diet of the Roman Legions.
After the fall of the Roman Empire in 455 C.E, the country was repeatedly sacked by the Visigoths, the Vandals and others. The people did their best to survive; there was no culinary development. But with the Renaissance, cuisine also flowered. Biscotti re-emerged in Tuscany, credited to a Tuscan baker who served them with the local sweet wine. Their dry, crunchy texture was deemed to be the perfect medium to soak up the wine (and how much more flavorful than dunking a donut in coffee!). Centuries later, many still agree that dipping biscotti into Vin Santo is a perfect way to end a meal, or to while away an hour at a café.
Answer: I use my regular biscotti recipe, and then I make a simple powdered sugar icing (1/2 cup powdered sugar to 1- to 1 and half teaspoons water, liquor or juice, depending on the flavor of the biscotti). I drizzle the icing on the biscotti, and let the icing dry just until the outside is hard enough it won't smudge, then store them in an airtight container. The moisture of the icing is just enough to take the hard 'crispy crunch' off the biscotti, while still getting a nice texture. I think of it as the perfect biscotti... firm and toasty enough to dip in coffee, but if I take a bit without dunking, it doesn't hurt the roof of my mouth.
Answer: I love baking biscotti and trying those made by my friends. Over time, I have tinkered with a few biscotti recipes. There is a fine line between making biscotti that are crisp versus biscotti that are hard. In general, I got a better texture (not as hard) by reducing the quantity of flour. To make the biscotti crisp, I slice them quite thin (about 1/4 inch) using a serrated bread knife.
Answer: Less cooking time is important for a soft Biscotti...Also when mixing make a soft dough that must be handled with a large spoon..Drop the dough batter one spoon at a time to form a long line of dough batter..Bake for twenty five minutes,,Remove from oven..Let cool then cut on diagonal...They are done at this time..Dont return to oven for second bake on each side,Bake only one time..
Answer: To make cookies chewier, try more egg yolks.  For that recipe I'd consider substituting one full egg for two egg yolks.  This adds fat, which inhibits gluten development and increases chewiness.
In general, though, if I was going for soft I'd not make biscotti.  I'd make drop cookies.
Comment: You mean substituting two egg yolks for one full egg, right?
Comment: @Jefromi - yes, so it becomes 2 eggs and 2 egg yolks instead of 3 eggs in that recipe.
Answer: Couldn't you just shorten the cooking time (or lower the temperature) for one or both of the baking stages?
Answer: I make Biscotti all the time and for a softer version just cook them less time..I bake the log for 15 minutes at 375 F then remove from oven let cool.then slice put back in oven for just five minutes standing up...Remove and you are done!

How to make softer biscotti?


How does 'The Stack' work?

Question: If I cast Tormented Thoughts on my 3/1 creature and to counter my opponent uses Disperse to return it to my hand, is my Tormented Thoughts wasted?
Comment: You don't cast Tormented thoughts on a creature. You cast in on a player.
Answer: The stack does not matter here. Sacrificing a creature is part of the cost of casting Tormented Thoughts (it says so on the card). By the time your opponent has a chance to cast a spell, the creature you sacrificed will be in your graveyard, and therefore not a legal target for Disperse.
Answer: You opponent can't interact with the creature because by the time he/she gains priority to cast Disperse, the creature is in the graveyard.
The process of casting Tormented Thoughts is:

Place the card on the stack
Announce modes (N/A)
Choose targets
Choose divisions (N/A)
Check targets
Calculate cost
Pay cost

After 7, players can regain priority.

How does 'The Stack' work?


Where are the outliner toggles in 2.8?

Question: The selection toggle arrows in the Outliner disappeared. Is there some preference in the settings that has to be turned on?
Answer: These are now hidden by default to provide a cleaner and easier UI for beginners while still presenting enough functionality for most common use cases.
For more complex projects or advanced users Outliner Restriction Toggles can be turned on or off and customized according to personal preference from the Filters pop-over in the Outliner header.
There you can choose which restrictions columns are visible in the outliner by default.
You can still control collection visibility restrictions if the columns are off from the context menu by right-clicking an object and accessing the Visibility submenu.
Comment: If the outliner view's space isn't wide enough, you might need to either scroll over or widen the view.
Comment: this is a great example of keeping existing functionality while hiding it for beginners <3

Where are the outliner toggles in 2.8?


How to query account balance use EOS api?

Question: How to query the balance of an account using EOS api? Is is possible to query account balance with public key or account name?
Answer: You can check balance using account name.
Check out get_currency_balance endpoint
Balances are specific to a smart contract.
Use eosio.token as code parameter for a system smart contract polling.
You can left symbol parameter empty to poll all the tokens.
Also you can get account names from public key using get_key_accounts endpoint


How does a single-photon double-slit experiment work?

Question: With respect to Thomas Young's double-slit experiment, I have heard that it can be done with a single photon.  But how does the single photon go through both slits?  And how far apart are the slits?
Comment: It makes no sense to do the experiment with just one photon.  Assuming your detector is sensitive enough to reveal a single photon, all you get is one dot on the screen.  What you probably heard about was, doing the experiment with an extremely low intensity light source---so low that it is unlikely that there is ever more than one photon in the apparatus at any given time.  But as lots of photons go through, one after the other, the dots that they mark on the screen gradually add up to reveal an interference pattern.
Comment: Is it really possible for one photon to make a dot on the screen?
Answer: The electromagnetic field is interacting with the slits and detector placed around it (say the screen) everywhere. You can make the field so weak that by Fermi's golden rule the probability of the field interacting with any point on the screen is so small that you see only one "hit" at a time. This does not mean however that we dealt with a photon travelling through any of the slits arriving at the screen. A photon is not a localized particle. It is a quanta that a can be annihilated from field when interacting with the fields in the screen with certain probability.


Disabling UEFI on a running Ubuntu system

Question: I have ubuntu 14.04.1 running with 3.13.0-93-generic kernel after a recent upgrade. UEFI is enabled from the begining. However I can see that some modules (e.g. virtualbox, DKMS) are not working and asking for disabling UEFI. My question is, if I disable UEFI from BIOS what will happen to the booting? Will is boot or not? It is a single OS system. Can someone explain exactly what will happen? I can't just disable the UEFI before knowing the consequences as it is a production system. Please help.
Comment: Another approach, not requiring removal of secure boot, [here](https://askubuntu.com/a/789534/65082).
Answer: The problem is not the boot mode (BIOS/CSM/legacy vs. EFI/UEFI); it's Secure Boot. With Secure Boot active, Ubuntu 16.04 requires that all kernel modules be cryptographically signed; however, third-party kernel modules, such as those for VirtualBox, are not signed in this way. Thus, Secure Boot prevents their being loaded.
Note that Secure Boot is an optional feature of UEFI, so you won't run into this problem with a BIOS-mode boot. That said, switching from an EFI-mode boot to a BIOS-mode boot to get around this problem is overkill and is likely to lead to follow-on problems.
Fortunately, it's possible to disable Secure Boot. The details of how to do this vary greatly from one computer to another, so I can't write a simple description of how to do this that's universally applicable. This page of mine, though, presents several examples of how to disable Secure Boot, so you may want to check it out.
Comment: Thank you Rod for the valuable information. However I am scared about the possible consequences after I change from UEFI to normal BIOS mode. Will it affect the existing running system? Is there any possibilities that the OS won't boot at all? Will reverting back to UEFI allow it to boot back up in case it has boot failure by the previous step?
Comment: Please re-read my answer. I recommended *against* switching from EFI-mode to BIOS-mode booting. See [this page of mine](http://www.rodsbooks.com/efi-bootloaders/csm-good-bad-ugly.html) for details of why. Note that boot loaders are written for one boot mode (BIOS or EFI), not for both, so if you switch the computer's boot mode, your OSes will stop booting until you install new boot loaders. Disabling Secure Boot is an *entirely different* proposition, with much less risk of catastrophic consequences.
Answer: You can disable it on most Toshiba laptops by pressing f2 while booting, this will let you enter the settings area, go to security and disable the secure boot, make sure you save and exist f10


Follow-up email to a company after requesting data

Question: I need help as to how can I send a professional follow-up email to a company (petroleum company) after requesting data from them a month ago. The data is in relation to natural gas volumes etc. The company has no obligation to send it however it's being requested by a university and I would like to know if they got the email since we got not reply and if any further assistance can be rendered.
Comment: Did you mention "University X" was requesting the data, or just yourself? A corporation will respond differently to requests made from individuals vs. institutions (especially regulatory agencies)
Comment: What made you wait a whole month before doing follow-up? Have you sent them any other emails since then regarding the follow up?
Comment: Possible duplicate of [What is appropriate email follow-up etiquette after no response?](https://workplace.stackexchange.com/questions/10203/what-is-appropriate-email-follow-up-etiquette-after-no-response)
Comment: Why is the university requesting you to get the data? Can they not ask the company directly?
Answer: Call the customer services number for the company in question and talk to somebody.  Be friendly and approachable and hope that you're speaking with someone helpful.  If they're not helpful, call again on a different day with the hope of speaking to someone else.
Describe who you are and the purpose of this request and ask what would be the best email address/phone number to use.
If you simply emailed the "contact" email address, it's likely that your email is in a large pit with many other spam and random emails, never to be read.
What you're trying to do here is target the person/department who can answer these questions directly.  It's a good skill to develop.
Comment: Would also recommend to call them to find the right contact for this request. You could also try to find PR / press department for some "official" figures. The website should help.
Answer: You don't specify in your question whether this was an enquiry sent to particular person or whether it was sent to a generic account.
If you sent it to a named contact then you could follow-up with that person directly, calling them up would probably be best since it seems that e-mail hasn't gotten their attention.
If this was a "cold" request (i.e. there was no prior relationship with the contact) then it's entirely possible that they ignored the e-mail entirely, especially if the request involved sending any data the company doesn't typically make public or if it required any significant time/effort investment to complete. I would suggest contacting the main customer contact number for the company and enquiring as to whether a) your request is something they could accomodate and b) who the right person would be to contact regarding it.
If it was sent to a generic contact e-mail then chances are that exactly as Snow states in his answer it has never been seen, or has been seen and discarded. Generic mailboxes are rarely monitored in much detail (the spam levels are simply too high) and it is often a fairly low level employee who is tasked with looking for specific sorts of inquiries and forwarding them up the chain. It's not unexpected that anything outside of what they have been tasked to watch for will simply be discarded out of hand amongst the 'noise'.


Interpreting exp(b)

Question: With respect to (binary) logistic regression and a categorical IV, State, if a given exp(b) is .08 and I'm using indicator coding such that my reference category for the variable, State, is, say, "Wyoming," how do I interpret .08? Presumably I contrast the .08 with the "mean" of Wyoming (with "mean" here being the proportionality, or number of positive instances, of Wyoming)...So if Wyoming = .06, do I multiply .08 * .06 = .0048?  That doesn't quite feel right...
Comment: What you need is a basic understanding of probabilities, odds, & odds ratios. It might help you to read my answer here: [interpretation of simple predictions to odds ratios in logistic regression](http://stats.stackexchange.com/questions/34636//34638#34638).
Comment: Thanks, gung--I read that excellent answer (among others) earlier today, which is what led me to the question I posed here. I broadly understand logits/odds/probabilities...but I may be over-thinking this, so I'm looking for explicit clarification of the relationship between the reference category and the exp(b).  My understanding is that the reference category cell mean comes into play in all of this somehow--but I'm just not sure how.
Answer: Let's imagine your response variable is percent urban, and that the mean of this variable in Wyoming is $.06$.  Since each person lives in an urban area or not, this means that $6\%$ of the population lives in an urban area.  You fit a logistic regression model to predict percent urban based on state, where Wyoming is the reference level, and you have one other state, say Montana.  The analysis returns an estimated coefficient, $\hat\beta_\text{Montana}$, and $\exp(\hat\beta_\text{Montana})=.08$.
That exponentiated coefficient is an odds ratio.  That is, it is a constant multiple associated with the change in the odds of 'success' (i.e., a person being urban) associated with a one-unit change in the covariate.  Because, you have categorical covariates, that is the ratio of the odds of being urban in Montana to the odds of being urban in Wyoming.  Since the odds of being urban in Wyoming is $.06/.94=.064$, the odds of someone being urban in Montana is $.064*.8=.00512$.  Now, to get the percent urban in Montana, you convert that odds to a probability $.00512/(1+.00512)=.00509\%$.
So I think you have this essentially right, you just need to convert the proportion in Wyoming to an odds before you multiply it by the odds ratio.
Comment: Perfect, gung, that was precisely what I was looking for.  Very cool.

Interpreting exp(b)


Does the thickness of a rubber sheet affect the tensile strength?

Question: I'm really confused which thickness of rubber sheet I should choose. Does the thickness affect the tensile strength and elongation in any way? Is there any relationship between them?
Comment: Have you tried looking for basic info at all?  At the least, read https://en.wikipedia.org/wiki/Ultimate_tensile_strength carefully, follow up with some of the references, and then come back here to ask a specific question.
Answer: The thickness of your rubber sheet definitely affects the force you will need to apply for a given amount of elongation.  Thickness also affects the breaking point, and therefore the tensile strength, of your rubber sheet.
Young's modulus describes the elastic property of a material up to the limit of its elasticity.  It's a measure of the force per cross sectional unit area required to stretch or compress a material.  It's the ratio of tensile stress (force per cross sectional unit area) to extensional strain (ratio of the amount of deformation to the initial length), along an axis subject to Hooke's law.
Young's modulus is expressed as pressure.  For rubber, it's 0.01 to 0.10 Gpa (per the table in this link: http://www.engineeringtoolbox.com/young-modulus-d_417.html).  If you click on the hyperlink in the paragraph above and scroll down to "Calculation", you can see how the modulus is calculated.  You can use this calculation with the specific modulus for rubber to determine the thickness of sheet you want for a particular force and elongation.
Strength is related to elasticity, but it describes the deformation of a material past the limit of elasticity.  The yield strength is the point at which stress applied to a material begins to cause it to lose its elasticity - to lose the ability to return to its original shape.  This is the point where plastic deformation begins, as opposed to elastic deformation.  Ultimate tensile strength measures the maximum stress that can be applied to a stretched material without the material failing.
Yield strength and ultimate strength are shown in stress-strain curves that plot force per cross-sectional unit area against the ratio of change in length to original length.
Answer: The geometry of the rubber sheet does not affect the tensile strength of the rubber. Think of the tensile strength as a property of the material: how much force it takes to break a certain cross sectional area.


How to fix VLC and vlsub ubuntu 14?

Question: I have installed VLC but the extension vlsub is not working. the version 0.9.10 only opens when there is no video playing and stay still. the version 0.9.11 appears two times and none of them open. what to do?
Answer: Cache folder is missing. Create using the following command
mkdir ~/.cache/vlc

Comment: That's a bit of sloppy coding from VLC not to create its cache directory, but after creating it manually, VLSub did show the search dialog instead of "Empty".
Answer: go to VLC repository updates and copy all codes in vlsub.lua then using any text editor simply open /home/kitori/.local/share/vlc/vlsub.lua
file on your linux machine ctrl+a then delete  and ctrl+v
Answer: I hope this fixes the problem.
curl ftp://ftp.videolan.org/pub/debian/videolan-apt.asc | sudo apt-key add -
echo "deb ftp://ftp.videolan.org/pub/debian/stable ./" | sudo tee /etc/apt/sources.list.d/libdvdcss.list
sudo apt-get update

Install VLC and Mplayer, and their support elements
sudo apt-get install vlc vlc-data vlc-plugin-pulse browser-plugin-vlc mplayer2

Install remaining Ubuntu 'restricted extras' (skip if space is critical)
sudo apt-get install ubuntu-restricted-extras

Enable full DVD support (depending on which Ubuntu release, these three packages may already be installed)
sudo apt-get install libdvdcss2 libdvdnav4 libdvdread4
sudo /usr/share/doc/libdvdread4/install-css.sh
sudo apt-get install gstreamer0.10-ffmpeg gstreamer0.10-plugins-ugly gstreamer0.10-plugins-bad gstreamer0.10-bad-multiverse

Comment: thank you so much for your help. but it still did not work. some commands couldn't finish or be found.
Answer: I think there's some problem with old version of VLSub(0.9). You can download the latest version manually from the Official VLC site VLSub Download and install it yourself, and it works just fine!
Steps:

Download VLSub
Copy to VLC Extensions Folder:
cp vlsub.lua ~/.local/share/vlc/lua/extensions/

It will be added as a menu in View in VLC named VLsub.

How to fix VLC and vlsub ubuntu 14?


How do I get Youtube Links to open in the YouTube app and not a browser?

Question: Everytime I click a link to a Youtube clip I have to choose which browser to open it in. I'd like them to open in the YouTube android app. Is there a setting somewhere that I can change ...?
Comment: If you're on a device with a newer HTC sense version (3.6 and up), there doesn't appear to be much you can do about it without root (and even then it breaks browser links to phone and maps)
Answer: If you have YouTube installed, the YouTube app should be one of the options you get to open the video. When you see this prompt, checking the "Set this option as default" checkbox will make every YouTube link open with the app (you might have to check the option again when opening from multiple browsers, I've had this happen).
Comment: To change the option later or if you accidentally chose the wrong one, you'll find the setting under 'Menu->Manage Applications' then find the browser or YouTube app (whichever you set as the default) and choose 'Clear Defaults'.
Comment: in my 'Manage Applications' the Browser app doesn't have any defaults set.  Does anybody know where those defaults are stored?


change owa password complexity message

Question: When changing the password in OWA 2007 i'm getting a generic error "The password does not meet the complexity requirements". Is there a way to actually give the detailed message about what that complexity is?
Answer: Nope. Windows account password complexity requirements are binary: they're set, or they're not. (Unless you've compiled a custom filter DLL for password requirements.)
https://technet.microsoft.com/en-us/library/cc786468(v=ws.10).aspx

Passwords must contain characters from three of the following five
  categories:

Uppercase characters of European languages (A through Z, with diacritic marks, Greek and Cyrillic characters)
Lowercase characters of European languages (a through z, sharp-s, with diacritic marks, Greek and Cyrillic characters)
Base 10 digits (0 through 9)
Nonalphanumeric characters: ~!@#$%^&*_-+=`|(){}[]:;"'<>,.?/
Any Unicode character that is categorized as an alphabetic character but is not uppercase or lowercase. This includes Unicode
  characters from Asian languages.
Comment: Sorry I should have been more specific, I want to change the error message that shows to the users. The error message is generic. Simply in red text it says "The password does not meet the complexity requirements". I want it to tell them what is required like what you posted above.
Comment: You might be able to trawl through the ASPX pages in OWA to find that string and replace it. Keep in mind that such customizations will not always survive your next Exchange update, so you'll have to re-do it (and it might be in a new place after the upgrade.)

change owa password complexity message


what does "Porn" mean in these words?

Question: on Reddit, I saw many communities named "Food Porn" "Earth Porn" "Album Art Porn" "Movie Poster Porn" and these community aren't about Pornography.
so what does "Porn" mean in these words? and what's the rule for structuring these type of word?
Answer: Images of real pornography are designed to promote feelings of lust or desire. Images of tasty food, luxury cars, lavish holidays etc are also aimed at promoting desire and, by analogy are called porn not because they are actually pornographic but because they give rise to similar feelings.
Answer: We see lavishly produced material, e.g. glossy magazines, advertisements, TV and video, etc, about houses, automobiles, certain confectionery, drinks, vacations, and we can talk of property porn, car porn, chocolate porn, wine porn, holiday porn. This is a readily understandable term, at least in the UK. No suggestion of sex or of excess or unhealthiness is conveyed by the term, although people like me who take a jaundiced view of advertising and media values may disagree about the last two. This use of 'porn' is clearly what the OP is asking about.
Comment: I have found something called a 'Cheeseporn cheese board' a $68 acacia wood cheese board with two cheese knives, which seems to be a brand from Barcelona  in Catalunya/Spain. However the same term in Google finds other things too, so maybe an unfortunate name choice by those Catalans.

what does "Porn" mean in these words?


Need to install a package without updating OR How to remote access RPi over the internet w/o updating RPi or using port forwarding

Question: As the question text reads, I need to enable remote access on my RPi over the internet without using port forwarding. I have a custom OS and can not do a general update without overwriting some of the customization.  I think that using weaved is great but it will not find the software using apt-get unless I do a general update first. I might be able to update a specific software if needed but not sure what those are.
Comment: So, you need to remotely setup the device, without being able to connect via the default SSH configuration? Why can't you update the RPi?
Comment: I am working on a customized image and can break it if I update the software. I have found through further research that the apt-get update does not actually update any software but instead the index of the repository so it is fine to use. Now given an updated repository I can get the software I need easily. I am using weaved and so far its great (even if its a little slow). Thank you for your response but I think I got it figured out.
Comment: Would you mind self answering then? It could help people with similar problems in the future :)
Comment: Please note that I rolled your edit to the title back, that's not how things are done here. If you think your answer sufficiently addresses the question feel free to accept it.
Comment: Thank you for doing so. It wont let me accept it yet. Gotta wait a few hours
Answer: I found that when using the apt-get update command does not actually update any software but instead the index of the repository so it is fine to use. Now given an updated repository I can get the software I need easily. This is as opposed to apt-get upgrade in which it will update (or "upgrade") the packages to the newest versions and thus ruining the customization of the system.


Can you spot an enemy jet from 3rd person view while on a jet?

Question: I would like to spot an enemy jet behind me when on a jet
Answer: I am not sure how you could see other jet in 3rd person, but I would suggest maximizing FoV and using freelook to keep your eye on the enemy. Also, spotting only works on people in the centre of your vision, so just spam 'q.'
Answer: If an enemy jet is right behind yours, you will know it by its bullets.
The best way to spot a jet its using mouse right click(freelook) and controlling the camera. I usually play inside the cockpit and I never managed to put the mouse center right over it when he is behind me, and it is risk to try it. You can try some maneuvers, to get to his side, under, over or back, it is better than to stay at its aim spamming "Q".
http://en.wikipedia.org/wiki/Air_combat_manoeuvring
I recommend you to stay way from maneuvers that put your plane perpendicular to the enemy, because in this game it makes you an easy target most of the time, but the immelmann turn is a good one if you are using the fighting jet to land some bombs.
Comment: "stay way from maneuvers that put your plane perpendicular to the enemy" I think this is a good advice. Still learning how to get enemy jets off my tail. There are a lot of good jet players right now which makes learning harder.


Can't search for flags in qalter's man page?

Question: I was trying to find out what qalter's -r flag does, but I can't search for -r when viewing the man page for it (pattern not found). Yet it's clearly there. If you scroll down a bit you'll see it. Why can't I search for flags in this man page? This online version seems to work fine though.
Comment: Works for me, pressing `/-r` plus `Enter`.
Comment: That's what I tried. I'm on gentoo using `xfce4-terminal-0.6.3` if that matters. qalter's man page is in the package `man-pages-posix-2013a`.
Comment: What about man pages of other commands (e.g. ls)?
Comment: I tried and it works in ls, gcc and cat.
Answer: It sometimes happens that man pages contain formatting commands and settings that lead to certain characters being rendered using various non-ASCII characters. This can be ⎪ instead of |,  (soft hyphen) or ‐ (hyphen) or ‑ (non-breaking hyphen) instead of - (ASCII hyphen-minus), ∗ instead of *, etc.
Try searching for non-ASCII characters in the man page:
LC_COLLATE=C LESS='+/[^ -~]' man qalter

You can force the man page to be rendered in ASCII by choosing an ASCII character set:
LC_CTYPE=C man qalter

Having shell options rendered with a non-ASCII alternative to - is a bug, probably in the man page soucre. I don't know enough *roff to know what the bug might be.


What check determines if a whip successfully latches onto a tree branch?

Question: If a PC wants to use his whip to wrap around a tree branch and then swing on it, like Indiana Jones, what check would that require?  Would it require an attack roll?
Comment: A good follow-up question is once you *have* cracked that whip, whether you need additional rolls to shape it up, get straight, or go forward.
Comment: Similar questions have been asked before and are not closed: [Breaking open a chest](https://rpg.stackexchange.com/q/74339) | [Forcing open doors](https://rpg.stackexchange.com/q/185647) | [Resisting Intimidation](https://rpg.stackexchange.com/q/73089) | [An appraisal check](https://rpg.stackexchange.com/q/57130) | [A Bargaining or Bartering situation](https://rpg.stackexchange.com/q/74653) | [Shield-surfing down stairs](https://rpg.stackexchange.com/q/185810)
Comment: In real life it's all one move you just flick your wrist and the end of the whip binds itself..   there would be the adfituonal move action of swinging though.
Comment: Also related: [Can you pull objects towards you with a whip or a similar tool?](https://rpg.stackexchange.com/questions/110585/can-you-pull-objects-towards-you-with-a-whip-or-a-similar-weapon-tool)
Answer: You probably don't need a check at all.
I read this question and my first thought was similar, there's probably a skill check involved. But that got me thinking: how hard should this actually be? So I set out to figure out if this was even possible, and discovered that not only is it possible, it's probably so easy that no check should be required at all.
I found this video from AdamCWM on youtube. In the video, Adam demonstrated wrapping the whip around a large branch while standing atop a step ladder, and then successfully swings from the branch. Now, from what I can tell Adam Winrich is a professional whip wielder, and an artisan craftsman when it comes to whips - obviously someone who would have proficiency with a whip. But the move he uses to wrap the whip around the tree branch is nothing special. In the video, he casually slings the whip over head in the direction of the branch and it works effortlessly. I don't mean to be an armchair whip user presuming upon my own non-existent skills, but I really think anyone could do the move he did to wrap the whip.
As for swinging across a gap, I have been proficient in rope swings since I was five years old. Any adventurer should be able to swing without issue.
Comment: A Strength or Athletics/Acrobatics check *might* still be worthwhile in some cases, just with a low DC (like 10 or less, depending). If someone's wearing full plate armor for example, it could be difficult for them to pull their body weight up off the ground via a vertical rope and swing across... if the swing is 5 feet, I probably wouldn't bother. But if it's more like 15 ft, and requires a bit of a jump at the end, or an attempt to curve around the trunk of the tree (e.g. swinging in for an attack or something), now we're talking about an opportunity to roll for success.
Comment: Mythbusters did it too! https://archive.nerdist.com/what-we-learned-from-the-mythbusters-indiana-jones-special/
Comment: Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/128495/discussion-between-thomas-markov-and-sam-lacrumb).
Answer: In general, I never want to call for two rolls to do a single task like "cross this gap", unless what you're actually doing is setting something up to make the same task easier for other party members, like throwing a grappling hook so that the party can scale a slippery cliff face more easily or constructing a makeshift bridge across a gap.
If you want to use a whip to swing yourself across a chasm instead of trying to jump it, I would definitely not call for two separate rolls to do it. That's heading into what some people call "rolling to failure", breaking a task down into enough rolls that you can virtually guarantee failure just because you'll eventually roll low. In general, if you're considering breaking up a task into multiple rolls, and failing one roll obviates any prior successes*, then they are probably not actually separate tasks and should be handled with a single roll.
In the described scenario, I'd probably call for an Athletics check, but I'd base it on Dexterity instead of Strength via the Skills with Different Abilities variant rule, because hitting your whip target and controlling your body in a swing seem like feats of agility to me, but it's probably not going to fall under Acrobatics.
Another way to look at it is, normally I'd call for a Strength(Athletics) check to leap across a gap that's too wide to jump based on your stats. A player who says, "Instead of jumping, can I--?" is asking to use a story reason to apply a skill and/or ability that they're better at, and that's entirely valid. Defaulting them back to the same skill check you would have otherwise asked for is actually denying what they're looking for by coming up with a plan beyond the brute-force solution. (Though sometimes my players' Cunning Plans get out of control and I do have to tell somebody "Well, you can try that, but you have a pretty good Strength, so it might be easier for you to just jump it.")
*To explain what I mean here: If you're trying to stealth through an enemy camp, each roll should basically represent bypassing an encounter. Yes, eventually you're going to get caught if the stealth section takes long enough, but each success represents a fight you didn't have. The fact that you eventually got caught doesn't mean the failure has obviated the successes you had previously. By contrast, if I'm calling for stealth checks at each guard, but any failure means you have to fight the entire camp, then I'm really just denying you the opportunity to be sneaky; only a perfect string of successes will mean actual success at the task, which was to sneak through the camp.
Answer: Do you even need a check?
We should keep in mind the advice from the DMG:

When a player wants to do something, it's often appropriate to let the attempt succeed without a roll or a reference to the character's ability scores. For example, a character doesn't normally need to make a Dexterity check to walk across an empty room or a Charisma check to order a mug of ale. Only call for a roll if there is a meaningful consequence for failure.

So, the DM should consider the totality of circumstance of this event when deciding whether a check is called for.  If this were an unarmed monk using a whip with both hands to swing across a shallow gully in the forest, then no check at all and just treat it as a free object interaction during movement.  If this were a heavily armored cleric who has just scooped up a fallen comrade and now has to carry the body across a chasm while supporting a combined weight in excess of their lift capacity while hanging from the whip with one hand - a check is definitely called for.  Between these extremes, it is the DM's call whether a check is called for.
If there is a check, what should it be?
To snare the branch - Tool Use
Acrobatics has been suggested, but is not the best fit, since the initial wrap-around is more about using the whip than using your body for a "stunt".

Your Dexterity (Acrobatics) check covers your attempt to stay on your feet in a tricky situation, such as when you're trying to run across a sheet of ice, balance on a tightrope, or stay upright on a rocking ship's deck. The DM might also call for a Dexterity (Acrobatics) check to see if you can perform acrobatic stunts, including dives, rolls, somersaults, and flips.

Rather than using the whip as a weapon, you are using it as a tool, a device to wrap around a branch and then support weight:

A tool helps you to do something you couldn't otherwise do, such as craft or repair an item, forge a document, or pick a lock...Proficiency with a tool allows you to add your Proficiency Bonus to any ability check you make using that tool. Tool use is not tied to a single ability, since proficiency with a tool represents broader knowledge of its use.

'You couldn't otherwise do' reminds us that no matter how good your jumping skills are, you aren't going to be able to grab that out-of-reach branch with your hands.  This recommends tool use over Acrobatics.  I would suggest Tool Use (Dexterity), with proficiency bonus added if you are proficient in whip as a weapon.
To swing across - Strength Check
Just a Strength check, not Athletics.  Strength checks are used for short events, whereas Athletics checks are used for longer or more complicated situations.  PHB example of a Strength check: "Hang on to a wagon while being dragged behind it".
Especially if all you are considering is "Am I strong enough to hold on to the whip while I swing?", then just a strength check.  However, if it is an entire complicated cinematic process - grab the fallen comrade, jump off the platform, swing across with enough impulse to cross the chasm while taking environmental damage, let go at just the right moment on the other side, stick the landing - then Athletics would be appropriate.  PHB examples of Athletics checks: "Cling to a surface while something is trying to knock you off" and "You try to jump an unusually long distance".
But which check, or should this be two checks?
OP Sam asks about a PC who "wants to use his whip to wrap around a tree branch and then swing on it".  Had they instead said a PC wants to 'swing across a gap using a whip', a single check would be appropriate.  Rule 1 is "The DM Describes the Environment" and presents the basic scope of options.  For me, how the DM envisions the environment determines whether this is one task or two.  It would certainly be a particularly challenging situation that would call for two checks, but if this is the intent of the DM I would want to respect their narrative structure.
It is true that more checks creates a higher likelihood of failure, and Darth Pseudonym is correct to caution us against "rolling to failure".
If one check, the check would be made for whichever part of two tasks above was the most difficult, or for whichever one carried a higher consequence of failure.  If this was a non-combat situation, I would advocate simply narrating a successful result of the whip snaring the branch rather than rolling - "After a few attempts, your whip wraps securely around the branch - now for the hard part" - because absent time pressure, there is no meaningful consequence of failure, unlike the swing.  However, if this was a combat or ticking clock scenario and the player wanted to do both these things on the same turn (and assuming that the DM indeed wishes to treat these as separate tasks) then both rolls would be required, because failure on the first roll1 would have the consequence of delaying the completion of the task in a way that was important to the narrative.
1 Or rolls.  I would allow one attempt per possible attack per a turn if the character had whip proficiency and Extra Attacks.
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/128347/discussion-on-answer-by-kirt-what-check-determines-if-a-whip-successfully-latche).
Answer: Most likely acrobatics followed by athletics
No attack roll would be involved since you aren't actually attacking anything and there is no AC to overcome.
Controlling the whip to loop around the tree branch would require a demonstration of finesse akin to the ribbon competition in gymnastics so acrobatics would be a good match.
Actually swinging on it would be athletics since you are using strength to push off and hold onto the whip while swinging.
Keep in mind that you can swap which stat is used for a skill check so you could arguably use athletics (DEX) followed by athletics (STR).
Comment: Also downvoting, but only because you're advocating two ability checks for a single task, namely, "use a whip to swing from a tree branch." Given 5e's task resolution system, requiring multiple rolls _massively_ increases the odds of failure.
Comment: Downvoter here. I think this answer is just factually incorrect. acrobatics just does not fit the description of wrapping a whip at all. I understand the comparison with the acrobat's ribbon. But I don't think the ribbon movement are not acrobatics in themselves (even thought they are something acrobats do) and the rule-description for the skill does not fit.
Comment: It's a side note (since this is not an answer), but I think if you're looking for a skill. Athletics' rule-description fit better (it just says "... covers difficult situations..."). Dexterity(athletics) sure. But not acrobatics.


setting older kernel version as default

Question: My OS version is Ubuntu 20.04 LTS. Recently I got a kernel update to version 5.8.0-38 but then I was facing a lot of hardware issues. Now I am temporarily on kernel version 5.8.0-36 generic. How do I set this particular version as default. I am completely new to Linux.
Answer: The simplest solution might be to enable Grub's GRUB_SAVEDEFAULT feature. Try this:

Open the Terminal
Edit the /etc/default/grub file: sudo vi /etc/default/grub
Change GRUB_DEFAULT=0 to GRUB_DEFAULT=saved
Add GRUB_SAVEDEFAULT=true
Save the file (Esc⇢:⇢W⇢X
Update Grub with: sudo update-grub

These settings will ensure that your system boots with the last kernel you chose during boot.
Now reboot, hold the shift key when your system comes back up. You should then see the Grub menu. Choose the Kernel that works for you. That will now be "default".
Hope this gives you what you need.
Comment: This saved my day. I was trying to switch to the other kernel on my ubuntu 20 VM as I messed up the original kernel/build folder. Thanks.
Comment: This is the solution. Congrats!
Answer: If you'd like to always boot specific version by default
you should

Edit /etc/default/grub file. Find GRUB_DEFAULT and specify path to the grub menu entry (something like GRUB_DEFAULT='Advanced options for Ubuntu>Ubuntu, with Linux 5.4.0-48-generic')
Run update-grub.

Note 1. You can find grub menu entries in /boot/grub/grub.cfg.
Note 2. I recommend to make a copy of /etc/default/grub before modification.
You can also check this link - I've created a note for myself some time ago.
Comment: Thank you, this works even when an additional kernel is installed (numbering 1>2 breaks in such cases).
Answer: I downgraded kernel version to install an old version of Nvidia driver. After the steps given by user1091774, I find that it is necessary to run sudo update-initramfs -u, otherwise DKMS still tries to build Nvidia driver against the latest version of kernel.

setting older kernel version as default


Aligning Cartosat-2 Image?

Question: Recently our company purchased Cartosat-2 Image from NRSC. Our Mining Lease area Boundary is not aligning with Image.It is around 100 meter offset.We are using QGIS 3.4.Spatial reference  of Cartosat-2 UTM Zone-45 and WGS-84 datum.Project spatial reference is GCS WGS-84.On the fly projection is there.
It aligned properly with LISS-4 Image.
Answer: Cartosat-2 scenes can have a misalignment of up to 100m. So your observation of the image not aligning with your shapefile is common. To solve your problem you need to georeference the Cartosat-2 image onto your shapefile or onto your LISS-4 image, which will be much easier and 'failure proof' depending on the size of your area. The process basically involves searching for common points in both images and calculating a transformation function. There are tools in QGIS for that.
Comment: @Ray Please consider upvoting and accepting this answer if it answered your question.

Aligning Cartosat-2 Image?


2012 Ford Explorer XLT v6 Misfiring and Bank 2 Air/Fuel Ratio Imbalance

Question: Have had a P0306 and a P0316 error codes for a while now and have changed the spark plugs, coils, intake manifold gasket, checked injectors and changed the injector for the cylinder misfiring(6). All of the sudden today a new error code has popped up, P219B and connected my OBDII scanner and see that the oxygen sensor B1-S1 has a current that fluctuates from -.05to .04 while B2-S1 is constantly between -0.30 to -0.17 all at idle. The voltage for B1-S2 is constantly at .80v while for B2-S2 it fluctuates from .07 to .11. The LTFT B2 is 14.84% while for B1 its 3.12%. At 1.75 rpm STFT B1 goes down to around 0 but B2 does not go lower than 3%. Also, I literally just drove over some snow a couple of seconds ago and now the Service AdvanceTrac light is on and Traction Control Off light is on. Fuel System 1 reads closed loop but Fuel System 2 is reading open(—). Intake air temp is 107.6 while ambient is 37.4.
Comment: Welcome to Motor Vehicle Maintenance & Repair! The IAT temp of 107.6° seems like a max, which would be throwing everything else off. I think you can test it, but I'd start with it and see if it's good/bad before pressing on to something else. The IAT temp should not be that far off of ambient (as a guess, I'd say +/- 10° from ambient).
Comment: What could potentially be throwing off the intake air temp though?
Comment: A bad IAT could definitely be throwing it off ... that's the reason I suggested you test it.
Answer: Aside from the the Traction Control warnings, your fuel trims, Fuel System readings, and P219B all point to lean misfire on the bank that includes cylinder #6.  Despite your repairs, P0306 and P0316 will likely return.
Check the condition of cylinder #6.  Perform a compression test on all cylinders with a compression gauge to check for a loss of psi greater than 15% on #6.  A quick, less effective compression check would be to floor the gas pedal on a cold engine, open the driver side door and crank the engine for 15 seconds, listening for an audible imbalance in the sound of the starter.
Another method is to check the power of cylinder #6 at warm idle.  Disconnect each spark plug boot -- or each fuel injector electrical connector -- one at a time.  Note the drop in engine RPM with each cylinder.  If #6 does not drop as much as the others, compression is bad (since you have already checked the spark, fuel injector, and air induction to cylinder #6).


botocore: how to close or clean up a session or client

Question: While doing some automation around AWS-EC2 with the botocore library in Python, I noticed a lot of HTTPS connections remained established that were no longer needed by processes that were busy doing other things (so killing them or recoding them to exit is not an option).  I think the botocore session and/or client object is leaving the connections to AWS endpoints established.  The botocore documentation shows how to start or create them, but not how to close them or clean things up.  I tried a .close method but it did not exist.  How can I get these connections to gracefully close without killing the processes?
Answer: I had the same issue, but from a slightly different angle: When closing worker threads, my log files would get cluttered with these warnings - also due to open connections:

Exception ignored in: <ssl.SSLSocket fd=4, family=AddressFamily.AF_INET, type=2049, proto=6, laddr=('[internal ip]', 49266), raddr=('[external ip]', 443)>
ResourceWarning: unclosed <ssl.SSLSocket fd=4, family=AddressFamily.AF_INET, type=2049, proto=6, laddr=('[internal ip]', 49266), raddr=('[external ip]', 443)>

After some time down the rabbit hole, I have figured out how to close the connections correctly, before closing the threads.
I'm using SQS with boto3, so you might need to modify the call a bit for it to work with botocore.
My example to produces the warning above is:
import boto3
import boto3.session
import warnings

warnings.simplefilter('error', ResourceWarning)  # Display warnings
session = boto3.session.Session()
sqs = session.resource('sqs', region_name=AWSregion)
sqs_q = sqs.Queue(url=SQSQueueUrl)
sqs_msg = sqs_q.receive_messages(MaxNumberOfMessages=1)

The SQS connection can be closed using:
sqs.meta.client._endpoint.http_session.close()  # closing a boto3 resource
sqs._endpoint.http_session.close()  # closing a boto3 client

Comment: Is this still the recommended way to close the socket? `_endpoint` is a private attribute
Comment: @AaronLelevier There is apparently no real solution, however the warning is a false positive. See: https://github.com/boto/boto3/issues/454
Comment: This doesn't work for me with boto3 == 1.20.52

for s3 `http_session` is  a URLib3 resource which has no close method


Turning hundreds to thousands profile on Instagram, scam?

Question: I had a friend tell me that she gave this girl on Instagram $1,000 and she turned it into $25,000 in minutes. She apparently does some sort of crypto/stock investing. She was told she has to pay a $3,000 transfer fee to get the money out, which is a percentage of the amount that is needing to be transferred. She sent me a picture of a pending $25,000 deposit in her cash app. Does this sound like a scam and is it even possible? Apparently one of her friends got her money out today and it worked for her? Seems kind of too good to be true.
Comment: Are you kidding? This sounds so much like a scam it could be used as the example in the dictionary under the word scam. The only way anyone would fall for this if their own greed clouded their ability to think clearly. There are a hundred ways this scam could work and explanations why this supposed other person "got money out". (hint: they didn't)
Comment: New Year, Old Scam...  I hope you keep your money and do something useful with it.  Happy New Year.
Comment: "She sent me a picture of a pending $25,000 deposit in her cash app." To give you an idea of how easy this is, https://imgur.com/a/P8SJYIN took me about 15 seconds to make.
Comment: What kind of friend is this?  Have you actually spent *actual* face to face time with this friend in the real world, or is this an "internet friend"?   The scam is obvious: they take $1000 of your money, then show you fake screens showing you now have $25,000 *but only in their 'special bank' that you can't actually get money out of... they then take $3000 more to get the money out, then no money ever arrives and you're down $4000.  It's also typical in confidence scams to make excuses to keep asking for larger and larger amounts of money, and 2-3x is the typical multiplier.
Comment: If everybody could turn $1,000 into $25,000 in ten minutes, wouldn't the world's finance system collapse, or money become worthless, or something?
Comment: If this were legit, the "investor" could just take the $3,000 in fees out of the $25,000 and send your friend $22,000 instead.  They'll just keep asking for money for BS reasons until the mark wises up and stops sending it.  Then they'll disappear.
Comment: There is no such thing as a legitimate and reliable get-rich-quick scheme.
Answer: This is a scam.  If this person had the ability to turn $1000 into $25000 on a whim, they certainly wouldn't need any money from you.  Either your friend is being scammed or your friend is a scammer.
Answer: Easy! Get six people to send you a thousand dollars.  Then get them each to send another three thousand. $24,000 easy as pie.
By the way, the person that it "worked for" in the original story is either completely fictitious or in on the scam. Almost certainly the first.
Comment: [Michael's Pyramid Scheme - The Office US](https://youtu.be/lC5lsemxaJo)
Answer: Everyone who solicits money from you, asking to turn it into lots more money later, is a scammer at one level or another.  The more extreme the claim, the more scammy it is.
Because exactly as Shawaron says, when somebody sees an investment opportunity that good, they keep it to themselves or "in-house". Most people who would even see such an opportunity are professional investment bankers, and they have a firm who employs them or personal connections to quality investors.  They are not going to solicit on Instragram, for Pete's sake*.
The same rule applies to "more seemingly legit" matters.

When you see a Web ad saying "The Fotley Mool gives a rare "all in" recommendation", they're trying to sell an expensive investor newsletter (with a fatal flaw, see end).
Most "financial advisors" in the US (who mysteriously work "for free") want to sell you expensive investment products that reward them a large sales commissions.  These are not very good investments, and you'd do much better in other investments.

Actual investment that works is super boring. John Bogle got sick of working in an industry basically tuned to giving consumers 20% gains in a market that actually gained 30%, and 15% losses when the market only lost 10% (and profiteering off the difference).   Bogle wrote a book called "Common Sense in Mutual Funds" which does just that about reliable ways to invest.  When you look at how small college endowments are invested, it's approximately that way.  But like I say, this advice is "super boring" and basically says DON'T try to pick stocks because that does not work, and focus on reducing overhead expenses.
If I were king, everyone would be required to learn and understand actual proper investing.  Then, they would be wise to obvious scams like the one you report.
Answer: It's called a Pig Butchering Scam.
One of the most convincing versions has her claiming she's busy and asking you to login to some sort of live chat with an employee of the broker she uses. She's given you her account password and the employee tells you how to place the trades for her. Every trade is amazingly successful.
If you don't ask her how to get in on the action yourself, she'll encourage you.
Once you've deposited, you too will get amazing trading advice. Everything will be perfect and you can make money even faster if you deposit more (and more). It's all super-profitable until you want to withdraw. Then the surprise taxes and fees will show up. She loves you so much that she'll even offer to cover half of the next payment if you act like you're about to give up on getting your money.
She and the account manager are having pork for dinner. You've been butchered.
Answer:
She apparently  some sort of crypto/stock investing

What kind of crypto/stock trading? Personally, I'd never make any kind of investment decision based on such a vague description; any legitimate opportunity will give you much more details about the actual opportunity.
Secondly, if it was really possible to make a $24,000 profit on a $1000 initial investment in a few minutes, why wouldn't everyone be doing it? The markets are generally pretty efficient, so this kind of opportunity generally doesn't last that long.
Finally, if she really can make those kinds of profits, why wouldn't she just do this with her own money? Why does she need your money? Why would she bother arranging a transaction that results in a $3,000 profit for her when she could've made another $24,000 profit in the same amount of time?
Large profits typically require months or years of investing, not minutes, and often require far more than $1000 initial investment.


effect of family history on incidence, adjustment for parents not yet being diagnosed

Question: I want to analyse a cohort study where individuals where followed for a number of years and to examine factors that influence occurence of disease (by a Cox model or logistic regression). One factor is family history (occurence of disease in patients, assessed at baseline). What adjustment is needed to allow for the fact that some parents may not yet be diagnosed - if its a disease occuring a lot in middle or old age (eg DM, CVD, cancer) - this is an issue I'd have thought when adjusting for age as younger individuals would likely have younger parents who although may be free od disease now may well be diagnosed in years to come.
Answer: Presumably all your index individuals are old enough to start seeing the disease in that group, and if so, it seems unlikely that you have parents of these individuals who are too young to have developed the disease. Although, it seems reasonable to be concerned that the parents may still develop the disease after baseline since there is certainly some a distribution of age at onset.
There are three potential options I can see (not mutually exclusive):

Adjust for parent's age, not just index individual's age, at baseline to deal with your concern about some parents being too young.
If you have information on the parents over follow-up, adjust for parent's disease status at over time as a time-varying covariate. Here, the tricky issue is whether you believe that the index patient's disease status could influence the parent's disease status -- if so, you will need to use methods like inverse probability weighting to adjust for potential treatment-confounder feedback.
Imagine you were going to do a randomized trial of the exposures you are interested in. In that imaginary trial, how would you define your eligibility criteria? Would you set an age limit on the index individuals and/ or their parents? Would you require any eligibility criteria related to the parent's disease status? If so, apply those same criteria to your cohort study through restriction.

Also, you may need to think carefully about why you are interested in family history, especially if you use option 2 above -- do you consider it a marker of genes or environment or both? Imagine a situation where an index individual develops the disease at say 40 and their parent develops it one year earlier at say 62. Would that be an indication of the same mechanistic role of family history as someone who develops the disease at age 63 when their parent had developed the disease 20 years earlier at age 65?


About sending gifts

Question: If someone gifts me something like a cake and I send the cake to another person , is it wrong in Islam?
I don't mean to hurt anyone. Also can you use a gift in a way the other person you think wouldn't like, for example I sold a phone my grandfather gave.
Answer: It isn't necessarily wrong to send a gift someone sent you to someone else.
For instance you might have used the phone your grandfather gave you, and later you give it away. Your grandfather would have understood because he knows that the phone he gave you is getting old.
It might be meritous if you give the cake to a needy person who doesn't have anything to eat. However if the person who gave you the cake heard about it,
He might get hurt. So its advisable to give the cake away without the knowledge of the person who sent it to you.
You must be your own judge. Wisdom cannot be taught like knowledge; it must be acquired through experience. Do what is right.
Allah knows best.

About sending gifts


How do I remove all metadata from a quicktime movie file?

Question: My camera takes .mov files as movies.  How can I remove all metadata from them so I can feel confident sharing them on youtube without accidentally sharing when/where they were filmed, what type of camera I have, etc.  A command line one-liner is nice, but if it's too confusing, a GUI program would be better.
Answer: Well, I have a command-line answer:
Note: This only works with the ffmpeg included in Ubuntu by default: it will have a version similar to 0.8.1-4:0.8.1-0ubuntu1; it WILL NOT work with any ffmpeg binaries you have installed from a third-party PPA or compiled yourself. Your mileage may vary.

Install these: sudo apt-get install ffmpeg libimage-exiftool-perl
Then navigate to where your source .mov file is, we'll call it test.mov
And run:

ffmpeg -i test.mov -map_metadata -1 -vcodec copy -acodec copy test-nometadata.mov

You can then use exiftool to check that it worked; exiftool test.mov and exiftool test-nometadata.mov should show you the difference.
Here are my sample outputs from an old Nikon .mov with tons of metadata (pastebin'd):

before - 80 metadata lines
after - 52 metadata lines (even the create, modify etc.times have been nulled)

(note that the order in ffmpeg above is essential -- the input and output files must be specified at the very end)
Comment: I get [this](http://paste.ubuntu.com/997540/) when I try to do as you've suggested.
Comment: That's because you're using a non-standard `ffmpeg git-2012-05-13-a927641`, not the standard libav one from the official repos. My version is `0.8.1-4:0.8.1-0ubuntu1` and works fine.
Comment: Ach.  That's because I was following [these instructions](http://superuser.com/questions/424015/what-bunch-of-ffmpeg-scripts-do-i-need-to-run-video-for-everybody) which required the latest ffmpeg.  I'll ask on meta if this question should be removed from askubuntu since it's not possible with ubuntu's ffmpeg.
Comment: -1, izx, what kind of order is that?! FFmpeg *clearly* assumes every codec stated before `-i` as the codec to parse input with. You can't parse input with **copy**. "Copy" is not a valid decoder, so naturally, the command will fail. You just have to move `-i test.mov` before the `vcodec`/`acodec` and it'll work. You might want to replace `vcodec` with `c:v` and `acodec` with `c:a` as well, since they've been deprecated for like… forever. This is **not** a deficiency of a "non-standard" version. It's just the latest version.
Comment: you know, then you might want to lobby Ubuntu to switch to ffmpeg instead of libav. I am well aware of the issues you point out BUT **this syntax is the only one that works with the (deprecated) ffmpeg included in Ubuntu's libav**. Our purpose at AskUbuntu is to work with whatever tools Ubuntu makes available by default, not help out with unofficial forks or even self-compiled bleeding edge git pulls or third-party PPAs.
Comment: @JohnBaber: this works perfectly fine with the ffmpeg that IS INCLUDED in Ubuntu by default as of this date -- and that is the somewhat obsolete version bundled by libav, the ffmpeg fork Ubuntu chose to go with last year instead of ffmpeg's ffmpeg.
Comment: Fair enough – I just can't imagine it's impossible to just use the correct command line, even with Ubuntu's bundled version (i.e. correct placement of the copy encoder and using `c:v` instead of `vcodec`). Can't you give it a spin and see if it works? That'd both help people who want or don't care to run a broken/outdated version *and* those who stay up to date or don't like running `libav` for whatever personal reasons *(You forgot the @-ping btw)*
Comment: @slhck: thanks; I will later today. FWIW, I prefer the latest ffmpeg.org versions myself. I will also try with `avconv`, which is what the libav folks have renamed ffmpeg to.
Comment: @slhck: `ffmpeg -i test.mov -map_metadata -1 -c:v copy -c:a copy test2.mov` gives a nice fat red  `Unrecognized option 'c:v' Failed to set value 'copy' for option 'c:v'` ; using acodec/vcodec after `-i` preserves the metadata in the output.
Answer: NOTE: with a recent version of ffmpeg (and presumably avconv, but I haven't tested that), you can simply use:
ffmpeg -i input.mp4 -map 0 -map_metadata -1 -c copy output.mp4

Using -map_metadata -1 creates an empty 'dummy' metadata source. For the version of avconv in the repos, or other outdated versions, use the method described below.

Using avconv (or ffmpeg if that's your weapon of choice, the syntax is the same):
The easiest way to do this is to set -map_metadata to use one of the input streams, rather than using global metadata. 99% of the time this should work.
avconv -i input.mp4 -map 0 -map_metadata 0:s:0 -c copy output.mp4

This will take the metadata from the first data stream (normally the video stream) and use that to replace the global metadata of the container file. This works because most of the time, the data streams have no meaningful metadata written to them; however, sometimes they do, and you want to completely get rid of that metadata. Unfortunately, the only way I can think of to do this used a pipe and two avconv processes.
avconv -i input.mp4 -f wav - | avconv -i - -i input.mp4 -map 1 -map_metadata 0 -c copy output.mp4

This takes advantage of the fact that WAV files can't contain metadata (since the format was created before metadata tags existed).
Both of these methods blanked all metadata on a file I just tested them on - all that exiftool reported on was the codec information, and avprobe reported no metadata to me. Using a pipe for this is pretty ugly, and the first method will work in 99% of cases, so that should be preferred.
BONUS: to create a blanked version of every MP4 in a directory, and then replace the metadata versions with the blanked versions (warning - pretty much irreversible):
for f in *.mp4; do avconv -i "$f" -map 0 -map_metadata 0:s:0 -c copy "out.$f"; mv "out.$f" "$f"; done


How can exchanges activate users' XLM addresses?

Question: Which method should be used to activate a user's XLM account to send them XLM?
We need to do it with someone's account that does not belong us.
Answer: For native asset (XLM), some exchange will determine whether the account exists in the Stellar network, if it exists, use the Payment Operation to send the asset, if it does not exist, use the Create Account Operation to activate the account and send the asset.


Simplest way to check if an audio level is line or micro?

Question: I can check level audio on a VU Meter or dBFS meter. What's the simplest way to check if an input audio level is line or micro? Can I use a multimeter?
Comment: For sine signals you may have luck with a multimeter, but I dont trust them for anything other than 50 Hz sines. you could connect some speaker/headphone and judge by the loudness or you could judge using an oscilloscope. But besides some difference in amplitude, the main difference between mic and line is the source impedance. you can only judge that well when you add a load e.g. headphones
Comment: Add as answer. How to measure using oscilloscope? Do I have to terminate by putting a load or a speaker before taking measurement with oscilloscope?
Comment: By "micro" do you mean "mic" which would be shorthand for "microphone?"
Answer: There are four typical audio levels (all values RMS):

Mic (microphone) level: 1 to 10 mV 1
Instrument level: 100 to 300 mV 2
Line level: 300 mV (consumer), 1200 mV (professional)3
Speaker level: Tens of volts. Varies by loudspeaker impedance, amplifier type, and volume level. (For example, a 400W (continuous) 8Ω loudspeaker might be driven with ~56 volts. (\$E=\sqrt{PR}\$)).

Anything below 100mV would be considered mic level and from 300 to 1200 mV would be considered line level. If you don't have a test signal, measure with an oscilloscope because your multimeter may only be accurate for 50 or 60 Hz AC measurement.
Comment: Wow! This is exactly what I was looking for.+1
Answer: Multimeter + cosine test tone will work.  Lots of cheap DMMs have ~200-1000 Hz bandwidth on the AC input, but double check yours with a known line level output and verify that you get the expected RMS amplitude.
Otherwise, an oscilloscope would be my first choice if you had one.
Comment: For using oscilloscope, do I have to terminate the audio port with standard load first? What are the expected rms values for line and micro levels? +1
Comment: @ak1974  Use a high impedance (1Meg) probe and do not terminate with any additional resistance.
Answer: Use cell phone with signal generator app. Measure AC sine wave 50 to 100 hz signal with high impedance instrument, e.g. oscilloscope. Connect the signal to the amp's input, e.g. line, aux, similar. Notice voltage drop. Use Ohm's law to calculate related signals. _
To find out cell phone output resistance (impedance) connect it to the measuring device, read signal value. Then connect a resistor to the output, e.g. a potentiometer of 1000 or 100 ohm. Reduce the resistance until the indicated voltage is half. Disconnect and measure the adjusted resistance of the potentiometer: It equals the output impedance of the cell phone audio connection. _
In a variation of both you can connect line input to cell phone output and in parallel a potmeter with higher resistance as described. Then measure the potmeter's value and calculate what value must be parallel to achieve the combined impedance. This is the value of the line input impedance. Be careful to keep output voltage of generator stable, else you end up with error, may be small, though. For relative / comparative measurements the absolute value is not highly important. An accuracy of 20% might be good enough.


How much of a restriction is it to require that ring homomorphisms map $1$ to $1$?

Question: Let $R$ and $S$ be rings with identity (both are not necessarily commutative). The standard definition of a ring homomorphism $\varphi:R\rightarrow S$ is a function which respects the addition and multiplication operations of $R$ and $S$. It is obvious that $\varphi(1)$ is the identity element of the subring $\varphi(R)$ of $S$. But it is not necessarily the identity element of $S$. A trivial example is the homomorphism which maps each element of $R$ to $0\in S$ (assuming $S\neq\left\{ 0\right\}$). A more interesting example is the ring homomorphism $\varphi:\mathbb{Z}\rightarrow\mathbb{Z}_{6}
 $ defined by $\varphi(x)=3x$ mod $6$ for all $x\in\mathbb{Z}$.
   I have noticed that some texts, in particular, Commutative Algebra texts, require that a ring homomorphism must map $1\in R$ to $1\in S $, ruling out the previously mentioned homomorphisms. I understand that one reason this is done is so that $R-$algebras can be easily made into $R-$modules. So my question is, how restrictive is this extra condition on ring homomorphisms? Are there any important homomorphisms ruled out when this condition is made, or do pretty much all important homomorphisms satisfy this condition ?
Comment: Given any homomorphism like yours, you can decompose it into a standard homomorphism from $R$ to its image $f(R)$ and the inclusion map of $f(R)$ into $S$. This inclusion map is a "homomorphism" that doesn't map 1 to 1. Is it important that the definition of "subring" include "the subring must contain 1"? In most cases, it is.
Comment: Do $R$ and $S$ have a unit? See also [this question](http://math.stackexchange.com/questions/270883/in-a-ring-homomorphism-we-always-have-f1-1).
Answer: A morphism should always preserve all the structure that is important. If you are discussing rings which possibly don't have units, then it doesn't make sense (it is not even well-defined) to require that $1$ maps to $1$. But if your definition of a ring requires a unit (as is the case in standard commutative algebra), then you should require it to be preserved in the definition of a morphism.
A similar example are ring morphisms which are not morphisms of local rings (i.e. they do not preserve the unique maximal ideal of the rings involved), as for example the inclusion $\mathbb{Z}_3 \to \mathbb{Q}$ (note that $\mathbb{Z}_3$ is the localization, not the quotient). If you discuss rings, this is a morphism. If you want to focus on local rings, it is not.
The reason why one draws this kind of distinction is that if you want to use things from (basic) category theory like products and coproducts (for instance), then the morphisms involved should really be morphisms of the category you are interested in, otherwise you don't get what you want.
Comment: @Daniel: I think in this context, formal logic is the fundamental justification -- if the constant symbol $1$ is part of the language of the theory, then homomorphisms between models had better map $1$ to $1$.
Comment: Sure, I agree. Still, the idea that morphisms should preserve "everything that matters" is understandable enough to be at least believable, as a general concept.
Comment: I believe that the category-theoretical reason is the most fundamental motivation to define the morphisms in a certain way. (However, it is not necessarily so easy to understand if you haven't worked at least a bit with categories...)
Answer: Requiring that ring homomorphisms map $1$ to $1$ definitely leads to a good theory; so much so that many mathematicians consider that to be the standard for what it means to be a ring homomorphism (as well as the requirement that rings have $1$) — and they would give a different name (e.g. "rng" or "$\mathbb{Z}$-algebra") to the notion that you call a ring (and similarly, "rng homomorphism" or "algebra homomorphism" for what you call ring homomorphism).
I would even say the majority of mathematicians are of this type, and using "ring" for the more general notion is old-fashioned (but apparently still taught often enough), but my perception may just be a function of the types of mathematics that interest me.


How I can change the object properties after I add it in the scene and move it?

Question: Suppose I add torus in my scene, and I change in the Minor segments from 16 to 3. In addition, I made many actions such as scaling, rotating and moving the object. How I can return to the Minor segments to 16 after all these actions? I do not add any actions in the edit mode.
Answer: Short answer:
You can't.
Long answer:
Blender doesn't create parametric objects out of the box. Once a mesh has been modified after initial creation (including translate, rotate, or scale) you cannot modify it further with the original tool creation parameters. Blender no longer considers the object a "torus", but it becomes a bunch of vertices, edges and faces instead, like any other mesh.
In the case of a torus you could use a curve to describe the basic profile and then use that as a bevel object on a circle curve.
https://www.youtube.com/watch?v=v9CXeprYW1M
There is an addon to create parametric objects https://www.blendernation.com/2019/12/04/blender-2-8x-add-on-review-parametric-objects-wmesh-free/ you might want to try it.


Shorter type A German slider coupler

Question: I have a kegerator and have a German beer on draft.  There are limited options in volume so it is a tight fit.  The type a coupler I purchased is too tall by roughly 1/4".  Is there anywhere I can look for a shorter version?
Answer: I have a (brand unknown) european-style faucet that came with a 90% elbow as an inlet. The fitting also fits on the beer-out of an A keg coupler, maybe something like that would save you some room?
There are also low-profile 90° elbows out there, a quick web search will show you who sells them.

Shorter type A German slider coupler


Legs gave out after 55 squats?

Question: I havent worked out consistently in 3 years, and have been trying to get back into it cuz i miss being skinny and fit. Im around 175lbs at 5'5" which is...not healthy at all if you look at the amount of fat compared to muscle. So i decided to get off the couch and work out again, starting with simple, easy-breezy exercises like squats without weights, mind you 55 squats was nothing to me back then with 40lbs added. 55 squats later (nonstop 55) my legs give out and i collapse on the floor like a sad fat kid. My quads would not cooperate for the like of me. The situation here was pretty much "help me, ive fallen and i cant get up". Now that i cant even do simple exercises.. what can i do to get back up there?
Comment: _Why_ are you trying to do so many squats non-stop??
Comment: I would read and follow this: https://fitness.stackexchange.com/a/24596/7091
Answer: Fitness is a sport of patience.
What you need to do is not trying to rush into getting fit again. You need to set goals 6 or 12 months from now and progress towards them.
Start with sets of 3 or 4 sets of 15 bodyweight squats. Bodyweight exercises are a great way to get back in shape before working out with added weights, do squats, push-ups, sit-ups, leg raises, pull-ups (or inverted rows if pull-ups are too hard).
You also need to make sure you eat enough healthy foods with the right nutrients and get ample resting time.
Answer: Simply enough, you've been three years out of the game, you're carrying more weight, and squats are more difficult than most people give credence.
The first thing you need to do is to rest long enough to be able to move without pain. You overdid it this time. You need to start with a lesser amount, and gauge results from there. There are any number of "X reps of this exercise in six weeks" programs available online. Here is one for squats. It's nothing terribly scientific, but it produces a guide for how many squats to do in each set. I got up to 30-40 in each set, 4 sets a night, when I last did it, before I got bored and moved on to something else.
The other thing that you may want to watch out for is overriding your body's natural signals via willpower. Some people are better at powering through discomfort and pain than others. I'm one of those myself. It's an issue because it means I'm prone to winding up unable to continue a program a few days later. If you find that you're prone to that sort of thing, intentionally pick a lower goal and work from there. It will mean that the first week or two will probably seem like you're doing nothing, but what you're doing is conditioning your body to the movement, getting it prepped. By the time it gets difficult, you will be significantly less likely to actually hurt yourself to the point where you can't get up in the morning.

Legs gave out after 55 squats?


Do I have to delete the question if the problem was fixed in the next release?

Question: I asked a question about a bug and possible workaround in Rails 3 beta. Now beta 2 is released and the bug is fixed.
Should I delete the question?
This particular question has no answers. Does it matter?
Thanks
Comment: @beau Done. (concise but too short)
Comment: No - if it was a full release of a product someone else might not have updated to the latest version yet and experience the problem, so leaving the question with the accepted answer being "upgrade" is the best solution.
Comment: As long as it says it's for BETA 1 in the title, I'd say keep it.
Comment: @chrisf I can't answer my own question and then accept it, right? So I keep waiting for an "upgrade" answer.
Comment: @art I think you can, you just have to wait 24 hours.
Comment: You can (or at least I think you can) answer your own question straight away (though in general it's polite to wait a while), but you do have to wait to accept it.
Answer: I'd just update the question to add the information you posted here.
Comment: I did (before posting here, just in case)
Comment: I was worried about breaking some rules. This downvoting thing is rather scary. Thanks for lending me support.
Comment: Oops... I probably messed up. I did what you said but accepted another answer. Is this okay? The other looked more authoritative to me. I don't know why. Oops! I'm leaving the third comment. Are there any limits on the number of comments? Don't answer, I'll check with FAQ.
Answer: Beta releases are somewhat a grey area, but it's very well possible that someone else has the same problem with the beta version and is not planning to upgrade (or unable to).
And some software can stay beta for a long time. Yes Google, I'm looking at you!
Comment: I don't think being in beta or not is relevant to the amount of people who can potentially have the same problem. For example many people used gmail while it was in beta, many more than the ones that use software considered out of beta such as, let's say, putty (the SSH client). Going even further I believe the "beta" label to be completely useless and arbitrary, many beta softwares is more stable than release software.


The physical realisation of a quantum oracle

Question: I am having doubts about the physicality of the quantum oracle used in the quantum search algorithms. The standard definition of the search problem (e.g Nielsen and Chuang) states that we are searching some set for marked elements. If we let the number of elements be $N=2^{n}$, and $x$ be the index of the element then we can describe the decision variant of the problem using the following function.
\begin{align}
    f(x)=\begin{cases}
            0, & \text{element of index $x$ isn't marked}\\
            1, & \text{element of index $x$ is marked}
         \end{cases}
\end{align}
The oracle is defined as a unitary operator that takes an $n$-qubit computational basis state as an control and acts on an "oracle" qubit if the control is marked,
\begin{align}
    \hat{O}_{f}|x\rangle|q\rangle=|x\rangle|q \oplus f(x)\rangle
\end{align}
My problem is, I can't see how we can physically have a quantum operator that can recognise the classical information of if an element index of a set is marked. The only way I can imagine this being possible is if the operator is designed knowing all the marked elements, in this scenario I don't see why the algorithm would even be useful. Could someone describe the physical realisation of this situation?
Answer:
You do not need to know the marked elements. In general, what the oracle does is helping you identify what you are looking for by bringing your qubits in such a state that (after applying some other gates, Hadamard is very common for example), you can tell the marked element (or whatever you are looking for, in general) from the result of the measurement/s.

Another simple illustrative example is the Deutsch algorithm: you have two types of functions: constant (either 0, or 1) or balanced (half the values are 0, and half are 1). There are such four functions given and you don't know which is which. Now pick a function at random and tell whether it is balanced or constant. I won't go into too much detail about the whole algorithm, but I just want to show what the oracle does.
The quantum circuit for this problem is the following:

The state of the top qubit after passing through the oracle is this:

After passing through the oracle, it gets through a Hadamard gate. It should be clear that after this, you can tell if your function is constant or balanced, because a Hadamard gate sends $ \ | + \rangle $ to $ \ | 0 \rangle $ and $ \ | - \rangle $ to $ \ | 1 \rangle $. So, depending on whether you get 0 or 1 after measuring, you get the exponents of -1 from above and therefore the function type.


Initialize a POJO dynamically from another method

Question: Let's say I have these set of POJO class that implement an interface but there are no common attributes here.
public interface MainIfc {}

class Ifc1 implements MainIfc {
    private String a1;
    public String getA1() {
        return a1;
    }
    public void setA1(String a1) {
        this.a1 = a1;
    }
}

class Ifc2 implements MainIfc {
    private String x1;
    private String x2;
    public String getX1() {
        return x1;
    }
    public void setX1(String x1) {
        this.x1 = x1;
    }
    public String getX2() {
        return x2;
    }
    public void setX2(String x2) {
        this.x2 = x2;
    }
}

And in conjunction with these POJO classes I have a couple of methods which I can use to retrieve the type of POJO being returned based on another value and the actual POJO with values.
public class GetIfc {
    public Class getIfcType(int code) {
        if (code==1)
            return Ifc1.class;
        else
            return Ifc2.class;
    }
    public MainIfc getIfc(int code) {
        if (code==1) {
            Ifc1 thisIfc = new Ifc1();
            thisIfc.setA1("Ifc1");
            return thisIfc;
        } else {
            Ifc2 thisIfc = new Ifc2();
            thisIfc.setX1("Ifc2");
            thisIfc.setX2("Ifc2");
            return thisIfc;
        }
    }
}

Is there a way using which I can read the concrete POJO safely in my code and use the getters/setters? I have gone through quite a few questions which provide answers based on Reflection but that isn't working for me. The getters/setters aren't visible and when I call .getClass() on the returned Object I see it is the MainIfc interface.
The design problem I am trying to solve pertains to a REST API automation framework that I am trying to design. Basically I have a ClientResponse parser which will send back the POJO I am looking for. But I don't want the folks writing the test cases to worry about the type of POJO that is returned. So I was thinking I could return the type and the instantiated POJO so I get the values but I am troubled over how to achieve this dynamically.
Comment: "when I call .getClass() on the returned Object I see it is the MainIfc interface." I find that hard to believe. Please add a bit of code that shows this behavior. Also please clarify: are you looking for any way to make it work, or are you interested in the proper OO way to solve this?
Comment: Can you provide example of how you expect to use this?
Comment: I am unclear what you are trying to do. I sense the desire for some Bean-like behavior but I may be mistaken.
Comment: You could add to your classes a method that returns all (public) fields as a List of `Field` objects. Probably a member of MainIfc. However, I feel like this is a X-Y-Question. What is the problem you are trying to solve?
Comment: I tried the answer mentioned here - http://stackoverflow.com/questions/8479943/very-simple-java-dynamic-casting. I have updated my question with the exact design problem I am trying to solve.
Answer: Try this code. Maybe this will return all the methods in class as well as methods inherited from Object class.
   public static void main(String[] args) throws ClassNotFoundException {
        GetIfc getIfc=new GetIfc();
        MainIfc clas1s=getIfc.getIfc(1);
        Class class1= clas1s.getClass();
        System.out.println(class1);
        Method[] mem= class1.getMethods();
        for(Method mmm : mem) {
            System.out.println(mmm.getName());
        }
    }

Comment: I updated my question for the exact requirement and design problem I am facing. Please advise.
Answer: It sounds to me like you're trying to do something rather illogical. Strategy Pattern or Abstract Factory might be a good fit for your requirement, but at the moment I don't quite understand what exactly it is you're trying to achieve. You should definitely not be conditionally casting and calling different methods on these classes. If you really want to continue on this path, I would suggest going with reflection, if not an option, and you need the flexibility, I'd probably go with a Map of some kind.
But I would definitely rethink your design if at all possible.
Answer: Try this piece of code, I don't know if I fully understand your requirement but based on my understanding I think below code would do the trick.
public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException,
    IllegalArgumentException, InvocationTargetException {
GetIfc getIfc = new GetIfc();
MainIfc clas1s = getIfc.getIfc(1);
Field[] fields = clas1s.getClass().getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
    Field field = fields[i];
    Class fieldClasslasse = field.getType();

    if (field.getModifiers() == Modifier.PRIVATE) {

    // you need to check fieldClass, if it is boolean then initials of the getter could be 'is' instead of 'get'
    String methodNameGet = "get" + Character.toUpperCase(field.getName().charAt(0))
        + field.getName().substring(1);
    String methodNameSet = "set" + Character.toUpperCase(field.getName().charAt(0))
        + field.getName().substring(1);

    Method methodGet = clas1s.getClass().getDeclaredMethod(methodNameGet, null);
    Object value =  methodGet.invoke(clas1s, null);
    if (value != null && value instanceof String) {
        String valueUpper = ((String)value).toUpperCase();

        Class[] cArg = new Class[1];
        cArg[0] = String.class;
        Method methodSet = clas1s.getClass().getDeclaredMethod(methodNameSet, cArg);
        Object[] var = new Object[1];
        var[0] = valueUpper;
        methodSet.invoke((Object) clas1s, var);
    }

    }
}

}

A little explanation about above code : Get all the fileds of the object and check if is a private property, if yes then it must have a public getter and setter, guess their name based on java convention, call the getter, get the value, check if it is a instance of String class, if yes make it UPPERCASE then call setter to set new value.
Answer: Do consumers of MainIfc actually need the POJOs, or just the data inside of them?
It might be cleaner design if MainIfc declares a method or two that exposes the data that its consumers will need.  Your POJOs can then implement the methods that the MainIfc interface declares.  Or you can build a wrapper class for each POJO that conforms it to the interface, if you want to keep the concerns of implementing your interface separate from your POJOs.
Ideally an interface should expose a few methods that can be used to interact with any class which implements it and no one should need to know about the underlying POJOs/implementation.
public interface MainIfc {
  public Hash getAttributes();
  public setAttributes(Hash attributes);
}

class Ifc1 implements MainIfc {
  private String a1;
  public String getA1() {
    return a1;
  }
  public void setA1(String a1) {
    this.a1 = a1;
  }
  public Hash getAttributes() {
    // return a hash with data that MainIfc consumer will need from this POJO
  }
  public setAttributes(Hash attributes) {
    // copy hash attributes to corresponding POJO fields
  }
}

class Ifc2 implements MainIfc {
  private String x1;
  private String x2;
  public String getX1() {
    return x1;
  }
  public void setX1(String x1) {
    this.x1 = x1;
  }
  public String getX2() {
    return x2;
  }
  public void setX2(String x2) {
    this.x2 = x2;
  }
  public Hash getAttributes() {
    // return a hash with data that MainIfc consumer will need from this POJO
  }
  public setAttributes(Hash attributes) {
    // copy hash attributes to corresponding POJO fields
  }
}


displaying taxonomy term as a header in a view

Question: I have a view that displays 3 latest articles from a certain taxonomy term. The issue im having is I need to display the taxonomy term as a Header. I dont see the [field_myterm] under Header > Global : Text area.. I also need this taxonomy term translated when I switch languages.
Answer: You should probably try to create a Taxonomy term View and not a Content View. Then, you could add a relationship (Taxonomy term : content with term) to fetch your node fields (or rendered entities). Add a taxonomy term filter to select your certain taxonomy term. Add a sort criteria based on descending post date (relationship with content). Display only 3 items. Finally, the taxonomy term name will become your View title and I guess you're done.
Comment: I tried this but its only displaying 1 node. I"m assuming its because of TAxonomy term: Representative Node...  The pager is set to display 3 though.
Comment: I have just edited my answer, the relationship I mentioned was wrong, sorry
Comment: No dice. I followed your advice but ended up with 3 duplicate of the same node. http://imgur.com/a/oKwS3
Comment: Check if your query settings is set to "Distinct" and add a sort criteria (Post date)
Answer: You can add the taxonomy term field in the list of fields that are shown for each node, and then use that field to group the results. It will give you a common header for the 3 nodes. It is not a view header, but with some CSS nobody will note it.
Answer: Have you tried the "Use replacement tokens from the first row"
You could create a hidden field and then you should see the twig token under "replacement patterns"