Does parents' family name refer to mother's married name or maiden name on VWP/ESTA form?

Question: The updated visa waiver form asks for my parents' "family" name, as shown below. Does this mean my mothers birth family name or her married family name?
Comment: @pnuts: That sounds like an answer to me.
Comment: @pnuts: But yours is different from the others, and you appear to have an authoritative source to cite.
Comment: @pnuts: heh... I looked at the `?` for that field, and didn't find any useful information. I guess you dug deeper. I still think your info would make for a good answer. I'd +1 it :)
Answer: It's always the current name, since this is what she's legally known as. Any records - criminal, legal, etc that they might want to look up - or to check your back story, that's how they'd find her.
If they want the maiden name, they'll specifically ask for that.
Answer: If she is married to your father and took his family name then as @pnuts said it's an convention to write this family name if it is not the case then I can't help you sorry.
The guidance about Parents is not specific on this point:

Enter the names of your parents. These are required to complete the application. If you do not know the name of one or both of your parents, enter UNKNOWN, for each parent. This field can include the names of your biological, adoptive, step-parent or guardian.
In the Family Name field, enter your parent's family name. The family name is required to complete the application. If you do not know one or both of your parents, enter UNKNOWN.
In the First (Given) Name field, enter your parent's first (given) name. Do not include the middle name in this field. The first name is required to complete the application. If your parent has no first name, or if you do not know one or both of your parents, enter UNKNOWN.

There is though some guidance regarding 'family name' for the applicant:

The most relevant portion (emphasis added):

Applicant Name
In the Family Name field, enter your family name as the family name appears on your passport under the Family Name or Surname field. The family name is required to complete the application.

This suggests that for your parents' names, you should enter their name as it appears on your passport, as well.
Comment: Do you mean, "enter their names as it appears on **their** passports"?
Answer: It is the name she goes by.  If your mother has been known as Jane Smith for 50 years, the fact that she was born Jane Jones is not of interest to the visa people.
Of course, why her current name is of interest to them escapes me.
Comment: Several people, including @Lilienthal, have suggested I amend my answer to refer to a "legal name".  In common-law jurisdictions like the US and the UK, there is no such thing as "legal name".  If you choose to call yourself "Buzz Killington the Third", that is up to you.  Obviously, if you are expecting the visa people to follow up with your mother in any way, it may be helpful to use the name they have for her on their documents already.
Comment: Good to know (initial comment removed).
Answer: For info I just had the same issue today. I emailed ESTA Support in the USA and they confirmed that the mothers' Family Name is indeed her MARRIED NAME.
Hope this helps.


Question about Narakas

Question: I want to ask the following: Is there a mention in the suttas or anywhere else that tells that there is a corresponding hell (Naraka) according to specific evil deeds? I wonder if it is a random thing or there is some corresponding hell to our evil deeds.
Answer: Hells must corresponding to their evil deeds. But there are uncountable various kamma leting their uncountable corresponding resultants arise in the same seconds, too. Kamma just waiting the proper chance to let their resultants arise.
Most of hell appear in suttanta, but it will be easier to explain the hell by abhidhamma's rule.
In abhidhamma, there are trillion mind moments in a piece of second. Each mind moment must managing, kamma, their mind and mind factors, but only javana-duty mind moments have own resultants, vipaka.  So, we done kamma over many thousands millions times each second.
And each kamma will multiply it's resultants, vipaka, such as just 1 killing mind moment of last life can let uncountable resultant mind moments arise through next life, if that killing mind moment can win to process rebirth-duty, 1st mind moment of each rebirth, of next life.
Another, many kamma can work together by switch their resultants' arising between each other, such as killing mind  moment let its resultants through niraya-man's life, then the other kamma let it's resultants arise
 by make niraya man very hurt his tongue.
Their are uncountable co-working in each second for one's life, such as a second of buddha's life on parinibbana's bed:

Wholesome kamma let budhha's bhavanga mind moment arise.
Each different wholesome kamma let buddha's each organ of 32 organs
look the best beautiful.
Unwholesome kamma let buddha's body sick.
The other wholesome kamma let buddha watch many ariya around the
parinibbana's bed.

These all happened only in a second, by a very various kamma. And this is just the example. In the full situation of this second, there are many various kamma giving their resultants.
Answer:
MN130
"Then the hell-wardens, seizing (such a being) by the arms, present him to King Yama: 'This is a man, your majesty, with no respect for mother, no respect for father, no reverence for samanas, no reverence for brahmans, no honor for the leaders of his clan. Let your majesty decree his punishment.'...

"The Commentary notes that not everyone who falls into hell is tortured with all of these punishments: some of the tortures are skipped; in some cases the hell-being's kamma is exhausted before the full round of tortures is completed, so that he dies and is reborn elsewhere; and not everyone goes for repeated rounds. Also, we should note that punishment in hell is not for an eternity. As the discourse implies, when the hell-being's bad kamma is exhausted, he dies and is reborn elsewhere, in accordance with his remaining kamma."

[Note: This is a gift of Dhamma and not meant for commercial purpose or other low wordily gains by means of trade and exchange.]
Answer: 'Hell' is 'suffering', 'pain', 'unhappiness', 'torment' &/or 'torture'. 'Hell' is described as undesirable unpleasant feelings, as follows:

Bhikkhus, it is a gain for you, it is well gained by you, that you have obtained the opportunity for living the holy life. I have seen, bhikkhus, the hell named 'Contact's Sixfold Base.' There whatever form one sees with the eye is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. Whatever sound one hears with the ear … Whatever odour one smells with the nose … Whatever taste one savours with the tongue … Whatever tactile object one feels with the body … Whatever mental phenomenon one cognizes with the mind is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable.
SN 35.135

The Pali suttas do not ascribe specific hells for specific unskilfull, heedless &/or evil deeds. For example, the Cula Kammavibhanga Sutta lists many types of unskilful actions & each action has the same potential general result of the 'unhappiness' of 'hell'.
However, if we use our common sense, we can discern in life that, in general (but not always), certain actions bring greater hellish results than another actions. For example, murder brings a longer prison sentence in hell than rape or corporate dishonesty; or the post-traumatic-hell of soldiers who fight in war is a greater hell than the hell of stealing or sexual misconduct. Or the hell of drug addiction is a strong hell.

Question about Narakas


How to configure a network printer in Ubuntu 14.04

Question: I have 2 printers on a home WiFi network that are accessed by 2 desktops running Windows.
I have a new laptop on which I am learning/trying Ubuntu 14.04.  How do I configure things to access these printers from the laptop?  There seems to be a lot of jargon that I don't understand or find confusing.  Step-by-step instructions would be helpful.
Comment: It might be helpful to say how the printers are configured in the network; for example, are they connected individually and directly to the 2 desktops running Windoze or are they WiFi printers accessed through your router?
Comment: This question may be too broad to answer as it stands.  What is the printer how is your printer connected? Is it attached to one of your Windows machines or connected directly to your network via a LAN cable. If its connected via LAN or Wifi how is it getting an IP address.
Answer: Network Printers are easy to setup
Open System Settings... from the Gear/Power button on top right corner of your desktop:

Click on Printers

Click on Add

Your Wi-Fi printers should show up under Network Printers. If they don't click on Find Network Printer and enter the IP address.
If you want to share your printer that is connected to Windows, use Windows Printer Via SAMBA.
For more help see the help on network printing with Ubuntu.
Comment: ... and which "connection" to choose, once ip address has been entered (and found) ? There's a huge list, ranging from AppSocket/.. Port / Com / LPT / pr / IPP......... :/
Comment: Why was this question closed as being unclear even though it's still being used as a duplicate question target? I voted to reopen the above question, because it seems like there's a disconnect here.
Comment: @nuttyaboutnatty I guess that will depend on your printer. My printer, an HP shows up at the top of the list. I just click forward and make the printer make and model specific choices.
Comment: Note: for Samsung printers that you really may be struggling with (ex: Samsung ML-331x Series, such as the Samsung ML-3312ND printer), you may need to use these external packages here: http://www.bchemnet.com/suldr/. It worked for me on this printer!
Answer: If your printers are shared and can be used in windows, this should be easy.
Open Settings->Printers and press on Add.
In the window that opens, expand the option Network Printer (under Devices) and choose the option Windows Printer via SAMBA.

You may see your printers listed here already. If so you can simply choose them. If not, then proceed.
Browse for your printer (by pressing "Browse") and that should be all.
Comment: His printers are WiFi network printers.


I deactivated my child account on the PS4 where I had all my games downloaded, reactivated it and I have to redownload them, why?

Question: I downloaded Minecraft and Tricky Towers on one of my accounts and it was accessible for both accounts I had. I made a new adult account so I could get PlayStation Plus, and then deactivated my others. The games are on the PS4 but I have to get the full version of Minecraft, and redownload Tricky Towers. How come this happened? I don't understand why I can't play the full version on the account when I reactivated it.
Answer: If I am understanding this correctly, you now have two different accounts: Account A that was a child account, and Account B that is an adult account. And going off what I can understand, you deactivated the Child Account and activated the Adult account. If the child account was the account that bought Minecraft, then that is probably why. Deactivated accounts can't share their games with other users until they are reactivated. Try activating the child account again and seeing if you can play it again. You should be able to have multiple active accounts on PS4 (I think Sony refers to them as Primary, not Active, but don't quote me).
(Also, if you had PS Plus in the past, it is possible that you got Tricky Towers for free, so that would explain why it is a redownload, not a full purchase. I know that is kind of off-topic, but figured it may help)


Defining continuity for functions between surfaces

Question: In general, considering function $f: M_{1} \rightarrow M_{2}$ between 2 manifolds, how does one formalize the idea of that function being continuous? Specifically, I am asking this in the context of needing to prove that if a neighbourhood of a point $x$ in the first manifold is in its' interior, then $f(x)$ is in the interior of $M_{2}$
Answer: Well both $M_1$ and $M_2$ are both topological spaces, so continuity of a function $f : M_1 \to M_2$ means the usual topological definition of continuity, i.e. $f$ is continuous if for every open set $U$ of $M_2$ we have $f^{-1}[U]$ to be an open subset of $M_1$.
Furthermore if $x$ is an interior point of $M_1$, then $x$ is contained in some chart $(U, \phi)$ where $U$ is an open set of $M_1$ and $\phi : U \to \phi[U] \subseteq \mathbb{R}^{2}$ is a homeomorphism and where $\phi[U]$ is an open subset of $\mathbb{R}^2$.
To show that $f(x)$ is an interior point of $M_2$ you need to show that $f(x)$ is contained in some chart $(V, \psi)$ where $V$ is an open set of $M_2$ and $\psi : V \to \psi[V] \subseteq \mathbb{R}^{2}$ is a homeomorphism for which $\psi[V]$ is an open subset of $\mathbb{R}^2$.
Comment: Ahh yes, forgot to add that in, thanks @Arthur
Comment: Thank you so much. Could you please also tell me whether the answer you have provided applies in general to $R^n$.?I'm sorry if that is a bit obvious, but I have only recently began studying topology, and I am thus still getting used to it.
Comment: @AryamanGupta No problem, I'm glad to help. Since $\mathbb{R}^n$ is a topological space this answer also applies to $\mathbb{R}^n$, but since $\mathbb{R}^n$ is a metric space to show continuity of a function $f : \mathbb{R}^n \to \mathbb{R}^m$ we have another way (sometimes more useful) to show continuity of $f$ apart from using open sets, known as the $\epsilon-\delta$ formulation of continuity, in this case we say $f$ is continuous at $x \in \mathbb{R}^n$ if $\forall \epsilon > 0$ there exists a $\delta > 0$ such that $d(x, y) < \delta \implies d(f(x), f(y)) < \epsilon$


Xbox driver for PS4 for mac?

Question: I have a Dualshock 4 controller and can't play certain games like portal because there is no PS4 support. I heard on windows are drivers that trick the computer into thinking that the PS4 input is an xbox input but can't find ANY for apple. Is there a workaround or are there drivers for mac that allow me to do the same?
Comment: You should edit the question's title. It's not clear from reading it what you want.
Answer: It might be a button mapping issue. I haven't tested it so I'm not sure it answers your question but here's what I stumbled upon today:

I used an app from the Mac App Store called, Joystick Mapper, although other apps are also available. This allows you to manually map each input from the DS4 to keyboard buttons on your Mac, effectively using the keyboard settings in games as your controls. For this example I mapped the inputs from my DS4 to the keyboard settings in Max Payne 3. If you look at the pictures below, you can see how I used the keyboard settings in the game to help me map the controller (click on the pictures to enlarge them).

http://www.backwardscompatible.co.uk/using-your-dual-shock-4-controller-on-a-macbook.html
The app is here: https://itunes.apple.com/gb/app/joystick-mapper/id528183797?mt=12

Xbox driver for PS4 for mac?


How can we test whether other possible worlds exist?

Question: Philosophers talk a lot about possible worlds. I am one person who does not believe any other worlds except ours exist. But how can I know if I am right? How would one know if other possible worlds exist? What experiment could tell if other worlds exist? And also, have any philosophers talked about this?
Comment: As philosophers talk about them, possible worlds are useful fictions for discussing something else. Even if they did somehow exist that would be entirely irrelevant to their uses in the talk, so the experimental question is moot. One philosopher, Lewis, who idiosyncratically believed that possible worlds "really exist" postulates them to be causally disconnected from our world, so they cannot be experimented upon in principle. All one can do is give some theoretical arguments in their favor, see his [modal realism](https://plato.stanford.edu/entries/ernst-mach/#HisCri).
Comment: See [Concretism](https://plato.stanford.edu/entries/possible-worlds/#Concretism): "It follows that [According to D.Lewis, the best known proponent of concretism] distinct worlds do not overlap, spatiotemporally; that no spatiotemporal part of one world is part of another. Moreover, given Lewis's counterfactual analysis of causation, it follows from this that objects in distinct worlds bear no causal relations to one another; *nothing that occurs in one world has any causal impact on anything that occurs in any other world*."
Comment: The question should make reference to specific possible worlds in specific philosophic writings, rather than building a strawman about what philosophers supposedly say.
Comment: Well, start off by meditating upon stuff we (think) we know. We are somewhere and there are apples.
Comment: The canonical way to seek answers to metaphysical questions is by prayer ;-).
Answer: There are a number of SEP articles about this and similar questions:

"Possible Objects."
"The Possibilism-Actualism Debate."
"Possible Worlds."
"Impossible Worlds."

A general strategy for "knowing about" possible worlds is plenitudinous platonism:

Balaguer defines plenitudinous platonism (somewhat roughly) as the view that there exist mathematical objects of all possible kinds, or the view that all the mathematical objects that possibly could exist actually do exist. But, in general, Balaguer would define a different plenitude principle for every different kind of abstract object. Linsky & Zalta develop plenitudinous platonism by proposing a distinctive plenitude principle for each of three basic domains of abstracta: abstract individuals, relations (properties and propositions), and contingently nonconcrete individuals (1995, 554). For example, on their view, the plenitude principle for abstract individuals asserts (again, somewhat roughly) that every possible description of an object characterizes an abstract object that encodes — and, thus, in an important sense, has — the properties expressed in the description.

Balaguer and Linsky & Zalta then argue that if platonists endorse plenitudinous platonism, they can solve the epistemological problem with platonism without positing any sort of information-transferring contact between human beings and abstract objects.

Implicitly or explicitly, for referential versions of the multiverse standpoint in set theory, something like "knowledge by acknowledged consistency" is a common justifier ("as long as the axioms are consistent and have consistent implications..."). Whether this should be seen as transferring to physical multiverses is a different, if related, matter.
Comment: @ kristian berry, I prefer platitudinous plentonism...
Answer: Most talk of possible worlds in philosophy uses that term in the sense of hypothetical worlds, or imaginary worlds, which are just supposed contexts for a particular idea. If you are a practically-minded person, that is how you will think of possible worlds. There are some people, however, who take the view that other worlds and universes exist just as our own does. There is no test we can perform today to rule-in or out such a view. Indeed, some people assert that there are other worlds which are disconnected from ours so that by definition it will always be impossible to test whether or not they are there.
Comment: There's some distinctly practical weirdness with cosmic and black-hole event horizons that I think is relatable to the second view. If you want a useful definition of existence, it seems you have to accept that there are places to which you can go that don't exist and never will, and places to which you can't go that do exist and always have. Adding a third category, places to which you can't go that never existed and never will that nonetheless aren't quite imaginary, seems compatible with this kind of describable place-ness, although I'd say *exist* is a poor word for them.
Comment: @gs Sure, but you can define "this universe" as everything that is (or was) causally connected to here, in either direction.  Then the one-way nature of black holes is not an issue.
Answer: To test you have to have data. Either you already have the data, that you can analyze and philosophize; Or you create your own data through experimentation.
For the data to exist there has to be some connection between the world. If the worlds do exist but there is no connection between them and us then there is no data and therefore you have nothing to work on.
There is another limitation. May be the data is there but your senses cannot be aware of them and therefore your brain has nothing to work on. We humans solve this problem by making machines that can sense what we cannot sense, such as magnetism, and translate it to us in something that we can sense, such as visuals (numbers which are when written just pictures, graphs etc), audios, vibrations etc.
About the specific test that you can do or we humans can collectively do, such as our advanced research institutes can do, there are many, too many to list. What I can do for you is give you directions to look at. Four directions.
The first one is to have lots of data. More data the better. Especially the data our senses cannot know about on their own. I gave one example already. Another is those electromagnetic waves that we cannot see.
Second direction is precision. We want more precise equipments. For example we can sense gravity but we cannot sense "gravity waves" (assuming they are real). Looking through microscope is a step in right direction for example.
Third and most important is to examine your theories. Don't take your theories for granted. See do they fit the data. If they don't then either the data is not correct (your observation or experimentation has errors) or the theory needs to be discarded or improved. Having correct theory goes a long way for you to achieve your goal.
You have to understand the basics of how this universe, our universe, our world works. This is very important because without knowing this you cannot distinguish between origin of a phenomena, that its in our world or outside.
For example, you have to understand that our universe is expanding, and not just expanding but also accelerating in that expanding. The way our universe works is that this requires energy. The source of that energy is not found in this world. It has to be coming from outside.
Answer: With a device called a Elitzur–Vaidman bomb tester.
Don't downvote just yet, I promise it's relevant to the philosophy. The other answers are not wrong that in a philosophical context, "possible worlds" generally refers to hypotheticals and imaginary scenarios. That is, a "possible" world is some state of the world that could be - it would be internally consistent and not violate any law of physics or logic - but is different from the actual state of the world.
Whether you ascribe to the Platonist position that these other possibilities have a "reality" equal to that of the world as it actually exists, or there is some character to the actual world that qualiatively differentiates it from possible-but-not-actual, the question of "how do I know" has the same answer - you need evidence, and according to Bayesian epistemology, you need evidence in the form of observations, rigorous experiment or not, that only happen in the event that possible worlds are "real." (Conversely, observations that come out the same way regardless of whether possible worlds exist or not don't help you)
An observation happening only in the event of a certain fact being true is, (reworded) what we mean by saying that the fact causes the observation. So to practically know that possible worlds exist, the possible worlds must be able to cause things in principle - their prescense must be able to impact our observations, otherwise all observations come out the same way regardless and no evidence will ever help.
Unfortunately, it's not at all clear how hypotheticals and imaginary scenarios could impact the actual world. Imagining a hypothetical can impact your future thoughts and actions, which would be observations, but whether that counts is questionable because the actual activity of imagining is done in the actual world. We can just ascribe the observations to that actual event and bypass the question. Maybe they somehow influence us from the Platonic realm? But then, if Platonic entities necessarily exist (because "a world is possible" cannot itself be a contingent fact) how can we even entertain what difference we would see in our observations and data if they didn't exist? And if we don't know what we'd see if they weren't present, we can't determine whether they exist when we see or fail to see that.

I think the bomb tester thought experiment illustrates this idea quite clearly because it's essentially the case study you're looking for - in the "multiple worlds" interpretation of quantum mechanics, they do have causal influence. Indeed, in this reading, all "quantum" behaviour is a result of multiple classical possibilities combining on top of each other. The actual mechanics of how that works aren't simple, but I will try to explain how it works briefly.
In the bomb tester (as illustrated by this diagram) you have a laser that emits single photons, and four mirrors arranged in a square. The mirrors in two opposite corners of the square are "half-silvered", which means that laser light hitting them has an equal probability to either pass through or be reflected. The laser light also has a "phase", which (briefly) works like this: if two laser pulses that are "out of phase" overlay each other, they cancel out and disappear, whereas if they are "in phase", they reinforce each other and are detected more strongly.
A photon emitted by the laser will first reach one of the half-silvered mirrors, at which point we get our "possible worlds" - in one, the photon has reflected off the mirror, and in the other, it has passed through unaffected. It is very important to emphasize that the photon has not split in two - the entire nature of photons is that they cannot be split into multiple smaller photons as we'd intuitively expect. The reflected "version" of the photon (deterministically) bounces off another mirror, and then into the second half-silvered mirror, where it branches again into two possibilities, heading to either detector C or D. It's also worth mentioning that despite the name of "multiple worlds", the whole world hasn't split, only the one photon.
What about the transmitted photon that continues to the bomb? The "bombs" in the thought experiment are either "working" or "broken", hence the need to test them. Working bombs absorb the incoming photon 100% of the time and explode. Broken bombs allow the photon to continue unaffected, also 100% of the time. It's very important to keep in mind that a given photon can only actually be observed being in one place, after which it is absorbed and ceases to be, and exploding the bomb counts as an observation.
If the bomb is working, we can just walk through the possibilities of where the photon is detected, which are, I must stress, mutually exclusive:

the photon ends up at detector C
the photon ends up at detector D
the photon hits the bomb, which explodes

The wrinkle comes in what happens if the bomb is broken. In that case, the photon sails past it, bounces off the mirror and into the far half-silvered mirror like it would if it'd gone the other way. It then splits into two possibilities as before, going to either detector C or D. ...But because it has been reflected off mirrors a different number of times in each case, the phase the photon ends up with at the end of each path is different. A photon avoiding the bomb and heading to detector D has the opposite phase as one that passes by the bomb and heads to detector D, and conversely, the two "versions" heading towards detector C end up with the same phase.
This means that, if the bomb is broken (or equivalently, not there at all) the two versions of the photon arriving at detector D cancel out and experimentally, a photon is never detected there - the photon is always detected arriving at C if there is no working bomb. This means that the corresponding list of possibilities is just:

the photon ends up at detector C, always

Now, the difference between the two lists is useful: cases 2 and 3 are what I was talking about earlier, they are observable events that can only happen when the bomb is present and working - IOW, they are caused by the bomb being present.
Now, the causality of case 3 is obvious - you can't detonate a bomb that's not there, and the bomb won't go off without the photon. So far so good. But what about case 2, detector D going off?
A photon can be detected at detector D only if the bomb is live, but the bomb is intact afterwards, because no actual photon reached its trigger to set it off - it hit detector D instead, and a photon can't be detected in two places at once. The possibility of the photon setting off the bomb has somehow influenced the final observed result even though it never "actually" happened.
I opened by calling this a thought experiment, but actual experiments have been done demonstrating the same effect, which has been termed "counterfactual measurement." While there are many ways to interpret QM, I personally find it very hard to find any explanations of this result that don't end up ascribing reality to the "possible" photon that could-have-but-didn't hit the bomb. I hope that helps answer some of your questions, and also illustrates that finding observational evidence of the normal sort of possible world (imaginary hypotheticals) is conceptually iffy because they don't work like quantum does, and need to for normal scientific methods to apply.


How to reproduce this line effect

Question: I am interested to find a proper way of reproducing an illustration like this example.
Comment: Possible duplicate of [3d Lines effect in Illustrator/photoshop?](https://graphicdesign.stackexchange.com/questions/101175/3d-lines-effect-in-illustrator-photoshop)
Comment: @Ovaryraptor That's not a duplicate. The linked case asks 10000% more altough it covers  the current question. The current question can also be solved mechanically like one existing answer already coarsely tells. Maybe someone adds the details. It needs a displacement map for bends. The rabbit in the linked question cannot be drawn mechanically.
Answer: This can be done manually by bending lines and editing stroke widths. The needed amount of work is substantial. Another answer suggests making line width modulations automatically in Photoshop. It's a good idea to save work. We try it, too. At first make an image which has

solid white backgound
50% grey shape, we call it N
solid black lines

To get acceptable sharpness the image here is 1000 pixels high.
You need later an exact copy of N. Make it into a separate layer.
Merge the white background, N and lines to a single layer, give to them Gaussian Blur

Treshold the image (Image > Adjustments > Treshold) for line width modulation:

The same can be achieved using Halftone Screen as suggested in other answer, but it needs different image color mode (=Bitmap) and quite complex settings. It creates the needed lines and the result will be sharper in low resolution, so it's well worth to be learned and tried.
The displacement needs the copy of N. Prepare the same N as the original onto a solid 50% grey background, N must have a white to black gradient fill.
Merge N and the grey layer to one and apply gaussian blur:

Save the Gradient N & Blur layer as PSD. You need the file as a displacement map.
Apply the saved displacement map (filters > Distort > Displace) to the line width modulated version of N:

The result:

If you have more blurred displacement map, you will get rounder result.
Actually I made all images in Illustrator and copied & pasted them as bitmaps to Photoshop for line width modulation and displacement map creation. My legacy Illustrator hasn't such bitmap functions. Everything can also be done in Photoshop, but to get the final vector drawing, you must trace the generated bitmap image, as said in another answer:

In Illustrator Live trace settings are critical for good results. It's very easy to get too much twists and bumps. In the screenshot you see settings which gave so good result that manual fixing is possible.
Expand the traced shape and remove exessive path anchors manually. Object > Path > Simplify distorts the shape too much, no matter what are the tool option settings.
Answer: I think this would be some plugin for illustrator (like this, not updated one scriptographer raster script) as in Photoshop same effect can be achieved by line raster.
In photoshop change image to Grayscale - use halftone screen - in shape choose line and play with frequency.
Then place image in illustrator and trace the picture.

How to reproduce this line effect


Possible to redirect to a page that uses standardSetController from another Visualforce page?

Question: Can a Visualforce page that uses a standardSetController be redirected to (with a list of records passed in) from anywhere other than a list view button?
Comment: Are you attempting to redirect in Apex, or JavaScript?
Comment: Either would fine. I have a Visualforce page where I want the users to be able to select from a list and then redirect to a Visualforce Page (from a managed package) that uses a Standard List Controller
Answer: You can't redirect in Apex, because redirects require PageReference, and PageReference doesn't support having a single query string key with multiple values. However, you can do this in JavaScript by constructing a URL that passes in multiple ids values:
/apex/pagename?ids=recordid1&ids=recordid2&ids=recordid3...

This was mentioned in a post from Skuid that documented the way to do it on this page.
Answer: You could go the route of cramming a bunch of Ids into a URL however, browsers have a maximum URL size which could cause problems for you.
Ideally, I'd recommend combining the two VF pages into a single page. That's probably the best bet. Create a wizard-like experience where they take action on a virtual page before the contents are replaced with a second virtual page.
You could flag all of the records before the redirect and then re-query for those flagged records on the destination page.
You could try to pass in a query to the new page via a URL. This is not ideal as it opens a window for SOQL injection. Even if you escape your query before using it a savvy user could edit the query to get to records you may not want them to get to.
This question got me thinking. I have not tried anything crazy like this, but you could try to parse your records into a hidden form and then instead of manually redirecting the user you can submit the form via javascript and post the data to your new page. Then you could try to capture the data using ApexPages.CurrentPage.getParameters(). I have no idea if this works but you can bet that I'll be testing it when i get time and posting my results here.


I somehow managed to break my hard drive - Please help

Question: I am trying to access a full disk encrypted hard drive (sda) on my computer that holds a Linux Mint 18 install but I am unable to get it to mount. My current installation is on the same computer but on a different drive. (sdb)
I cannot boot from this drive. If I try the message is that it has no file system to boot from.
lsblk shows:
NAME                                          MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                                             8:0    0 465.8G  0 disk
├─sda1                                          8:1    0   487M  0 part
├─sda2                                          8:2    0     1K  0 part
└─sda5                                          8:5    0 465.3G  0 part
  └─luks-d1e57395-383f-4e0e-8be5-e4726f21adda 252:4    0 465.3G  0 crypt
sdb                                             8:16   0 465.8G  0 disk
├─sdb1                                          8:17   0   487M  0 part  /boot
├─sdb2                                          8:18   0     1K  0 part
└─sdb5                                          8:21   0 465.3G  0 part
  └─sda5_crypt                                252:0    0 465.3G  0 crypt
    ├─mint--vg-root                           252:1    0 457.3G  0 lvm   /
    └─mint--vg-swap_1                         252:2    0     8G  0 lvm
      └─cryptswap1                            252:3    0     8G  0 crypt [SWAP]

e2fsck:
sudo e2fsck /dev/sda1
e2fsck 1.42.13 (17-May-2015)
/dev/sda1: clean, 305/124928 files, 77714/498688 blocks

sudo e2fsck /dev/sda2
e2fsck 1.42.13 (17-May-2015)
e2fsck: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda2
Could this be a zero-length partition?

sudo e2fsck /dev/sda5
e2fsck 1.42.13 (17-May-2015)
/dev/sda5 is in use.
e2fsck: Cannot continue, aborting.

I can mount sda1 but when I try to mount sda2 the terminal shows:
sudo mount /dev/sda2 /mnt
mount: wrong fs type, bad option, bad superblock on /dev/sda2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

and sda5:
sudo mount /dev/sda5 /mnt
mount: unknown filesystem type 'crypto_LUKS'

So I don't really know what I am doing which is probably why I have this problem in the first place but I was hoping somebody could help me to be able to mount the hard drive, if only read only, so I can pull some important files from it. I know my crypt password. Is there a way I can recover this data. Perhaps I can rebuild the file system?
Edit:
I tried to mount sda5:
sudo cryptsetup luksOpen /dev/sda5 samsung
[sudo] password for user:
Enter passphrase for /dev/sda5:

then:
/media/samsung $ sudo mount -t ext4 /dev/mapper/samsung /media/samsung/
mount: wrong fs type, bad option, bad superblock on /dev/mapper/samsung,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

Comment: Possible duplicate of [Mount a LUKS partition at boot](http://askubuntu.com/questions/21025/mount-a-luks-partition-at-boot)
Comment: Linux Mint is off topic here.
Answer: Your drive is a LUKS container which most likely contains a LVM volume group. Before proceeding, make sure that you have cryptsetup and lvm2 installed.

Open the container:
sudo cryptsetup luksOpen /dev/sda5 samsung

Activate the LVM logical volumes:
sudo vgchange -aay

Check what you now have in lsblk:
sudo lsblk


how to use 2 shotgun mics for videocam with external mic input

Question: I need to record an interview (2 persons) but can't use lavaliers.  What about using 2 shotgun mics (e.g. Rode Videomic pro) on tripods, wired to the external mic input of a Sony Handicam (CX580).  I.e. how to adapt 2 3.5mm stereo outputs (mono source) to one 3.5mm jack.  Or is there a way simpler solution for bidirectional recording?
Thanks
Answer: if you have two persons in the interview, hire a boom operator with experience.
she or he will handle the audio side and you can focus on the interview.
Answer: Your mic input can only handle one mic.  you need something like the zoom h4n to record two
Answer: As above, your Sony Handicam is only equipped to handle one input, probably a 2.2v (switchable from the lcd menu) jack input. This will allow power to low end shotgun (condenser) mic such as the Rode Videomic and others in that range.
I'm not an expert, however, I would say that if you find that particular adapter to combine two (3.5mm) shotgun mics into one, that it would not work anyway.
Your best bet is like what the others recommend, purchase either a separate mixer/recorder or hire a boom swinger with their own equipment.
If your are finding yourself in this position frequently and with not much budget you should probably consider purchasing a separate recorder such as Zoom H4/5/6 series or Tascam DR 60d (approx. $200).
Setups like these all depend on your budget, resources and how much you spare, or borrow from others (i.e universities, or hire shops)
Good luck!


show cimy user fields in users.php with manage_users_columns

Question: I'm trying to add code to my themes functions.php to display fields created with the Cimy user extra fields plugin in the dashboard users.php. I know that I need to use manage_users_columns, but beyond that I'm stuck. Anyone familiar enough with the plugin to help me get the proper fields to display?
Answer: I hacked my way into figuring this out. Here's the code for reference:
function theme_column_userfield( $defaults ) {
      $defaults['theme-usercolumn-userfield'] = __('fieldname', 'user-column');
      return $defaults;
}

function theme_custom_column_userfield($value, $column_name, $id) {
      if( $column_name == 'theme-usercolumn-userfield' ) {
            return get_cimyFieldValue($id, 'fieldname');
      }
}

add_action('manage_users_custom_column', 'theme_custom_column_userfield', 15, 3);
add_filter('manage_users_columns', 'theme_column_userfield', 15, 1);

Comment: @user2041 You should accept your own answer so that people know this is resolved.
Comment: Is this possible for custom post types like -

add_action('manage_videos_custom_column', 'theme_custom_column_videofield', 15, 3);
add_filter('manage_videos_columns', 'theme_column_videofield', 15, 1);
Answer: A couple thoughts that might help you or others reading this...
FWIW, the priority parameter doesn't have an effect unless you have multiple functions that you're attaching to the hook. So, 15 or 1 or 9999 is irrelevant. In case you might be thinking the priority has anything to do with column order, it doesn't.
Also, you can attach the 'theme_column_userfield' function to the manage_users_columns hook with add_action...it works the same either way. ie.,
add_action('manage_users_columns', 'theme_column_userfield');

works the same.
Lastly, the code block doesn't include any sort of ordering. Done this way, the column will be added to the right side of the table. If you need to insert the column somewhere you'll need to use a little bit or a lot of array_slice and array_merge depending on how simple/complex/reusable you need to be.
For example, if you used this...
    function add_new_column($column_headers) {
        // slice off the checkbox column
        $cb_col = array_slice($column_headers, 0, 1);

        // create the new column (you could add in translation if you want it)
        $new_col    = array('new_column_name' => 'New User Column');

        // stick it all back together
        $column_headers = array_merge($cb_col, $new_col, $column_headers);

        return $column_headers;
    }
    add_action('manage_users_columns', 'add_new_column');

    function output_new_column($value, $column_name, $id) {
        if($column_name == 'new_column_name') {
            // add some code here to print out whatever value you want in whatever style you're after
        }
    }
    add_action('manage_users_custom_column', 'output_new_column', 1, 3);

...the 'New User Column' would appear right after the checkbox in the Users list, followed by all of the rest of the default columns.


How to restore the /etc/passwd file?

Question: I was doing some experiment about resource-accessing. By mistake, I executed this command,
$ sudo mv /etc/passwd /etc/passwd.bak
Then I could not execute any command with privilege(eg. sudo mv /etc/passwd.bak /etc/passwd). When I shut the system down, I could not boot it any more.
Afterwards, I restored the passwd file with a LiveCD.
Any other approaches could make it?
Answer: Maybe this: When the bootloader shows up, add
init=/bin/bash

to the kernel parameters. Instead of booting normally (with the init process spawning all the other services including login), you should end up in single-user mode with a root shell (no password is asked) and be able to restore the passwd file. On some distributions you may need to manually remount the root partition in read/write mode before moving the file:
mount -o remount,rw /dev/sda123

(I don't want to test your issue and see if this solution works :)
Comment: That seems to be available. I will test it myself. Thanks a lot.
Answer: You can use "sudo su" to keep a root terminal open. That way, there is no need to login with sudo each and every time, as the terminal will always be root (until you close it, of course). If you accidental move the file, you can move it back from the root terminal because you'll still be logged in.
Comment: I did that by mistake, so I didn't realize what would happen next.

How to restore the /etc/passwd file?


Is it possible to move the view with holding spacebar?

Question: So right now when I want to move the view I use shift middle mouse button and move. But is it possible to move the view with spacebar and moving the mouse?
Answer: In Blender 2.79 (and maybe 2.8, but I haven't seen that) go to File/User Settings, click on the Input tab at the top, and there you have the different areas with their commands and hotkeys.  At the top is a field where "Name" is written - click on that and change it to "key binding" then you can type in the known hotkey in the Search field, (where there's a magnifying glass) to find the command you want, and then you can change it..  I typed "shift" and "middle" and before I typed "mouse button" the command was shown underneath with the hotkeys next to it - you can click on "mouse" and change it to keyboard, then in the field beside it and press on the spacebar
Edit -  I just reread your question and you want it to be Spacebar plus Mouse - so try clicking around and finding out what your options are - that's the place to do it anyway.
Comment: amazing this works even in 2.8!
Answer: I was able to set such behavior with the following steps in the Blender2.8 keymap.

Added "Pan View ([view3d.move] command)" to 3DView> 3DView (Global). Registers the keyboard space bar in "Click Drag" mode.
Uncheck "Frames> Play Animation" if you don't want it to conflict with animation playback.
Answer: I've made an AutoHotkey script that uses Spacebar + Mouse Buttons to send the default Blender keymap navigation commands as well as allowing for Animation/Tool/Search behaviour via spacebar to still work as expected if space is just taped without trying to navigate.
I should add that it's possible to set up navigation in Blender using Spacebar without Autohotkey but you get RMB context menu conflicts and loses the native spacebar Animation/Tool/Search functionality.
EDITED (2020-03-22): I've replaced the code with a newer one that alleviates a previous bug I coudn't solve where LMB clicking suddenly stops working if using the "Send/SendEvent" command. Now I'm using Click command only and it works as expected.
EDITED (2021-05-13): Simplified a some parts.
<code>; JoelArt | 2021-05-13
if not A_IsAdmin {
  Run *RunAs "%A_ScriptFullPath%"
  ExitApp
}

#IfWinActive ahk_exe blender.exe
#NoEnv
#Persistent
#SingleInstance Force
SetKeyDelay,-1
SendMode Input

$Space::
start := A_TickCount            ; measure current time.
KeyWait, Space                  ; wait for Space to be released.
duration := A_TickCount - start ; calculate if Space was held for less than ### ms.
if (duration < 180){            ; if so
    SendEvent, {Space}            ; send Space else send nothing.
}
return

$LButton::
if GetKeyState("Space", "p"){ ; If Spacebar is being held down while Mouse button is pressed.
    Send {MButton Down}
    KeyWait, LButton
    Send {MButton Up}
return
} else {
    Click, down ; Click is necessary over Send as the button sometimes stops responding for unknown reasons.
    KeyWait, LButton
    Click, up
    return
}
return

$RButton::
if GetKeyState("Space", "p"){
    SendEvent, ^{MButton Down}
    KeyWait, RButton
    SendEvent, ^{MButton Up}
    Return
} else {
    Click, down, Right
    KeyWait, RButton
    Click, up, Right
    return
}
return

$MButton::
if GetKeyState("Space", "p"){
    SendEvent +{Mbutton down} ; Use SendEvent "+" so not to trigger the shift+space command in Blender.
    ; Middle mouse seems to work differently for some Logitech mouses so comment out these lines -->.
    ; KeyWait, Mbutton
    ; SendEvent, +{Mbutton Up}
    ; <-- to here.
    Return
}
else {
    Click, down, Middle
    ; Middle mouse seems to work differently for some Logitech mouses so comment out these lines -->.
    ;   KeyWait, MButton
    ; Click, up, Middle
    ; <-- to here.
    Return
}

; Middle mouse seems to work differently for some Logitech mouses so use these lines instead. These are not needed with a mouse that works as intended -->.
MButton up::
    SendEvent {Mbutton up}
Return
    ; <-- to here.
</code>
Copy the code and save it as ****.ahk file and run it after installing the Autohotkey program.
Note that in order for RMB to not trigger the context menu during navigation you need to go into Prefs > Keymap> and search for Key-Binding "Right Mouse" and change all the ones with "context menu" in the views and editors where you navigate, like Object Mode, Mesh, Node, UV Editor, etc. Open the each tab and change "Press" to "Release" and it will work just fine.
Finally, if, you get weird mouse click behaviours, has happened to me a few times, just do ctr+alt+del and click "task manager" on windows and things should go back to normal, if not, exit and relaunch blender and possibly the scipt again.
I use this setup daily and it has worked really well for me :)
Comment: MS Windows only?
Comment: I created this on Windows as I don't have an easy access to IOS but if Autohotkey works on Mac then it could potentially work right out of the box or maybe with some modifications.
Answer: no :) click shift and middle mouse button and drag the mouse to strafe across the screen.
Comment: This is incorrect, you can customize most default mappings
Comment: So what do I have to customize it to map it?


Does echolocation work in these conditions?

Question: The inhabitants of a small city carved into the side of a cliff are blind and use echolocation to navigate.
There is a lot of empty space, around a kilometer of between the cliff side where the village resides and the other cliff side, in other words a 1km valley.
Will echolocation still work effectively in this kind of situation?
Comment: Yup. Were it not true bats wouldn't be capable of echolocation in the great outdoors in any kind of wind. However, if you want a more precise answer, please modify your question to include the maximum wind speed and a detailed description of what you mean by "a lot of empty space." Are we talking valley with mountains and trees? The Sahara Desert? A small town (population 2,000ish)? Open water?
Comment: Bats can fly in open spaces. Echolocation helps bat's to determine the distance and direction of both prey and potential obstacles, with the lack of echoes just meaning that there are no obstacles or prey to worry about. The wind might be a bigger issue than the open space.
Comment: @ProjectApex How does wind affect echolocation?
Comment: @Mister Onion I couldn't find the exact effects, but given that changes in the weather [affect the intensity and speed of sound](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980448/), and that wind, like sound, results in the movement of air molecules, there's a chance that it might cause some issues, but I doubt it'd make echolocation impossible, at best it should cause a minor need to adjust to the wind.
Comment: You might also be interested in https://en.m.wikipedia.org/wiki/Silbo_Gomero and https://www.newscientist.com/article/dn28052-ancient-whistle-language-uses-whole-brain-for-long-distance-chat/ where whistling is used for communications across valleys and ravines. Perhaps it could be used in combination with echolocation. Echolocation is typically short range for spatial information.
Comment: Yes it's quite possible. Many species of bats use very sophisticated echo location which is the equivalent of chirp sonar. Bats live in caves and can find their roosts in caves amid thousands of other bats signals. So if an equivalent system is used these inhabitants should be able to cope very well. Note echo location of this sort is short range <100m
Comment: Can these inhabitants fly?   How did they end up there,seeing as no evolutionary path would bring sightless species to either a cliffside or, more generally, to an illuminated location?
Answer: Yes, in combination with other skills
Your residents are going to use a combination of techniques to navigate. Echolocation is a way of avoiding obstacles, not of navigating over longer distances. In the Wikipedia image below, the bat can tell that there's a box ahead on its left, but the bat has no idea what's on the other side of that box.

If your villagers want to walk from the church to the blacksmith shop, for example, they'll have to have an idea of where both places are located and generally how to get between them. Here's a great overview of how blind people in the real world navigate from Chicago Lighthouse:

When in familiar places, visually impaired people generally know the
layout and memorize where things are. Learning to travel in different
or unfamiliar places is done by using orientation and mobility (O&M)
skills. Orientation is the actual planning of how to get to and from
places. Blind and visually impaired people use other senses – like
sound, touch and smell – to orient ourselves to our surroundings. So,
if I am walking outside and know there is a school nearby, then I can
assume that it is near when I hear children playing and laughing.
Likewise, the smell of freshly baked bread and cookies tells me I am
near a bakery.

By adding echolocation into the mix, you're giving your people a much better ability to avoid walking into objects. But they still won't be able to get around using that skill alone. They'll start hearing the hammering of the blacksmith and know that they're getting closer to the destination. As they approach, they'll be able to use echolocation to avoid running into the anvil.
Comment: Adding to this: RL human echolocation is pretty low on detail unless specifically trained, with range depending heavily on the types of sounds and the size of objects. There have been situations where I could find buildings via echos (mostly multistory buildings on a small college campus), and situations where I could not (giant parking-lots for shopping centers, where the buildings are too small and far. Giant parking lots are kinda awful without some clues that carry well, or really obvious car-corridors). So it depends on the precise details.
Comment: "unless specifically trained" is a really big deal here.  A normal person would have a hard time knowing if they are about to walk into a wall, but well trained persons have been known to be able to ride bikes through city streets being capable of perceiving everything they need to from traffic to sidewalk curbs.
Answer: Anecdotally: probably. Compare the Horseshoe Canyon Ranch, which is in the Ozarks. The Louisiana Center for the Blind takes blind trainees there annually, with lots of room for said trainees to wander off unsupervised between (and sometimes during) scheduled activities.
More relevant to the question (it isn't precisely a city carved into a rocky canyon, after all), there was this time when I was there with a group of mixed skill levels, returning to the lodge from the rock-climbing area. In terms of layout, the lodge is in the middle of a shallower slope, at the bottom of a steeper section where visitor cabins are, and the climbing area is up a completely different, steep and rocky slope, across a gap which I assume is around 0.25km or so in width based on how long it took to cross. On this particular evening, we'd taken a different path for some reason, rather than the more direct gravel road connecting these areas, instead going down the rocks and crossing a big meadow . Things were going slowly, and some people were needing extra assistance (lots of big rocks and such on the way down), and for this I was quite useless, and permitted to go on ahead if I wanted. Somehow, absolutely nothing went wrong. It turns out that even Ozark-sized mountains close together are sufficient to navigate by, without requiring additional clicks (the ambient acoustics were quite sufficient), and as I got closer, voices from the lodge were audible. I also suspect that, had the lodge been silent and I'd veered away from it too far to catch echoes from the building, it was still sufficiently apparent which side of it I was on, so I'd've just followed the slope/road, whichever I'd've hit first.
There was also this small playground behind the lodge, not directly in contact with any sidewalk or other structure people would likely frequent. The equipment was not very tall, as playground equipment goes, and it was little more than one family-sized structure in the middle of a box of gravel. Knowing that it was behind the lodge somewhere, and that nobody else was paying attention to it was sufficient to find it, though I will point out that the information was necessary (it was not simple to pick out ambiance reflecting off it before getting very close to cane's reach of the conspicuous boundary).
While my travel/mountain skills might have been unusual at the time, my echolocation is on the poor side - useful, but not reliable. The most reliable day-to-day passive echolocation is hard to describe, just because it's always there in the background. The most salient example in a non-canyon context, for me, would probably be my front yard. I'm far enough from the road, with enough trees, that it's easy to fail to distinguish my house from trees or the neighbors' fence, especially if there's not enough sun/traffic and I'm away from the driveway. The clearest cue is the garbage can, because it has a very distinct echo profile, being just large enough, and having the right material/hollowness to be picked out from farther away than, say, a random person of the same height. The driveway also ends without sidewalk quite a way before reaching it, but normally I can echolocate it before reaching the end of the driveway. Which, of course, means that if I'm coming back from taking the garbage to the road for pickup, it's a lot harder to find the way back. (LCB helped a lot with this particular problem, and I eventually did have a stone path installed from the driveway to the porch, but before those things, the echoes from that thing were a rather big deal).
All this is with fairly passive echolocation (not that I didn't try clicks / snaps once or twice when looking for the playground / garbage can). People who train to echolocate learn how to use different clicks to different ends, for things like range vs detail / area, etc. My experience is something of a lower bound, and a full-blown city with generations of experience to build on would outperform the one impressive feat to my name on a daily basis. The biggest consideration I'd keep in mind is range and levels of detail, and range will depend on both the size of objects and whether or not there are other object around to obscure them.
One thing I have never encountered, even though it makes a ton of sense to me, is strategic use of windchimes. Neither the LCB apartment complex, nor any of the blind staff's houses had any such decorations whatsoever. No school for the blind with a multibuilding campus that I have ever visited has utilized chimes. The NFB national convention uses ushers who form a path of criers, shouting directions (rather than going the Disneyland route and having speakers replay the same message from the 70's on a loop), and that is the most I have ever encountered as regards deliberate audio signage. It's enough to make me question whether or not a canyon city full of blind people would bother, even though someone with, say, a shop in the middle of the canyon would probably want to draw attention to themselves somehow. (The NFB convention's market / exhibit hall just had a maze of long tables with Braille labels to indicate what you were passing. You'd have to know to constantly check the table for labels, of course.)
I expect the real answer is "yes, but do not rely exclusively on echolocation; it has gaping weaknesses, and temperature / noise / environment can influence it positively or negatively."
Answer: There are some exceptional real worlds cases of humans using echolocation, take a look at https://en.wikipedia.org/wiki/Human_echolocation to see a few. There are videos where people avoid obstacles, sink basket balls and take hikes along rocky paths. In a demonstration in a documentary I can't recall the name of Ben Underwood could even successfully detect small objects on a table, and he could distinguish wooden objects from metal ones . Most of these people are exceptional, in the sense that they discovered their ability and worked it out themselves. In your community though, echolocation is normal. IRL exceptional skills are probably normal in your cave, and the exceptional cases would be really cool. Finding a hanging rope to climb somewhere? No problem! Workers throwing bags of turnips to each other from a cart? Sure! Spear hunting? Why not? Spear hunting fish? Maybe.
As has been noted though, the resolution of echolocation is courser than that of eyesight, and this becomes a problem over large distances; you could compare it to a low-resolution camera where far away objects are eventually within the same pixel.
Also, over large distances sound is distorted, and reflections, wind etc will compromise perception. There will be some sound though, so people can probably "see" some blurry picture at least. If gravel, smooth granite, limestone, rough granite and slime-covered, moist granite all give of distinct echoes, you could maybe tell enough about far off structures to get a sense of direction, and if nothing else know what type of local environment you are in; though echolocation often assumes that the person using it makes the sounds themselves, the way in which surfaces reflect ambient sounds are important as well.
Also, like @CAE Jones and @Andrew point out, many places make distinct sounds by themselves. Playing children, dripping water or a smithy will all be little beacons which will help people navigate.
Let's also not forget the possibility of various hearing aids. Fairly simple parabolas can produce surprisingly focused beams of sound, and one could easily imagine these people using cones, tubes and various other shapes to direct, magnify and otherwise manipulate the sound according to their needs. This is not to speak of all the possible devices to generate special purpous sounds for certain types of echoes, or devices that detect certain sounds. All these aids, ranging from the equivalents of glasses or binoculars to observatories, would be either carried by people who need them, kept in most homes or stationed in certain buildings, maybe watchtowers.
This said, other senses would also be important. Except for touch, in the form of rails along paths where echoes are impractical and so on, I think foremost of heat. If you are outside on a sunny day, you can feel where the sun is and use that to navigate much longer distances, but even more miniscule differences could be useful. Does the cave become progressively colder the further in you get? Can you feel the difference in radiation from the warm opening of the cave from it's cold interior? There could also be differences in the behaviour and temperature of the wind depending on what your surroundings look like.
Answer: The power level of the echolocation signal in bats is similar to that of the sounds the human voice can produce (order of 100 decibels). This allows the animals to perceive objects over distances never recorded to be further than 20 meters. https://pubmed.ncbi.nlm.nih.gov/22978903/
Regardless bats have also specially adapted receiving organ devices. The better human echolocator I've ever withnessed was that on Stan Lee's show "Superhumans". A blind man who could slowly drive a bike in a silent parking lot.


Can frequency affect loudness?

Question: I don't think there is any relationship in frequency and loudness, and frequency only affects the pitch of the wave. But could a really high frequency somehow affect the amplitude of a transverse wave in real-life conditions?
Comment: Please be more specific.  The intensity of a sound can be measured by instrumentation.  The loudness of a sound is what humans interpret as sound intensity, and that interpretation does indeed depend on frequency, whereby sound must be very intense on the low end (e.g., 20 Hz) and high end (e.g., 20,000 Hz) of the "human range" in order to be heard.
Comment: One also has to watch out for implicit assumptions. If you ask "How does chaning the frequency affect the loundness?" when you mean "How does spinning the frequency dial on this sound source affect loundness?" the answers you get may be based on incorrect assumptions.
Answer: I first want to clarify a few terms as they are commonly used in acoustics:

Frequency is the number of times per second that the sound pressure changes from low to high.
Amplitude is an objective physical measure of the strength of the sound wave. For a sound wave with an amplitude of 1 Pa, the high sound pressure is the atmospheric pressure plus 1 Pa, while the low sound pressure is atmospheric pressure minus 1 Pa. Put simply, sound amplitude is often expressed logarithmically as decibels.
Loudness is the subjective perception of how strong the sound is. This perception depends on individuals' hearing. For example, someone with age-related hearing loss would typically percieve a high-frequency sound as less loud than someone with "normal" hearing.

People's hearing is also more sensitive to some frequencies than others. In other words, if you play sounds at different frequencies but the same amplitudes to a person, he or she would perceive them as having different loudness. This effect is often characterised through equal-loudness curves such as the ones below.

Sounds along each of the red lines are, on average for humans, perceived as equally loud. This shows us that people are much less sensitive to low-frequency sound, and most sensitive around 3–4 kHz, although this effect diminishes as sounds get louder. This is a well-understood effect that is taken into account when setting limits for or measuring noise from e.g. traffic or industry.
I hope that answered your question!
Answer: I believe that Erlend gave a quite instructive answer, so I will try to stand only on one point of your question. You kinda mix loudness, amplitude and frequency in a more objective way than a subjective one (as would the inclusion of loudness in the conversation would demand), and you seem to be interested to know if the frequency of a wave would affect (somehow) its amplitude.
First of all, frequency is the repetition rate of a "phenomenon" and shows how often something is happening. It is not very clear what "a frequency could affect the amplitude" means, so I will assume that you are asking whether at very high frequencies the wave behaves differently.
In the most fundamental treatment of waves we assume that the media in which sound "travels" are linear in nature. This is of course not always the case, definitely not the case in real life and sometimes even a not so good approximation. Now, in these simple cases (in an ideal massless string for example) the amplitude of the frequency components depend on the properties of the medium, the boundary and initial conditions. Apart from that we assume that otherwise the medium treats the waves with different frequencies in a consistent way.
Of course in real life this in not the case and attenuation as well as propagation in media are frequency dependent (dispersive media in the propagation case). For example, most often than not, high frequencies are attenuated faster than low frequencies.
That being said, if you don't take into account the non-linearities then the answer is no. On the other hand, since you ask about real-life, non-linearities play a role here. Unless one considers a resonant phenomenon though, you can't really have extreme amplitudes on specific frequencies. Even when it comes to resonances, many real life vibrating systems exhibit high damping or even low coupling to the surrounding medium to produce so high amplitudes in a very narrow bandiwdth.
Answer: The low frequency can be lower than high frequency if the number of watts per hertz is constant.
A wave can be having many smaller waves like a box with several small boxes inside them and we are having two values for the number of waves

Can frequency affect loudness?


Meter shows hot but my outlets in my living room not working

Question: Everything on the breaker works but my living room outlets, and my meter shows 110 volts. Everything else on the same breaker works fine.
Comment: What type of meter, and how are you taking the measurement?
Comment: The reason I ask, is because if he's measuring hot to ground. He would get 120 volts, even if the neutral was broken.  However, the broken neutral would cause devices not to work.
Comment: It's an hyper tough meter and it's got elec, battery and we got it set on 250 my husband has worked on elec for years but this has him stomped
Comment: Sorry, what I'm asking is... When measuring the voltage, what are you measuring between (hot -> neutral, hot -> ground, etc)?
Comment: He's done both I think but I know he done hot to he third hole which is neutral I think
Comment: would you mind posting the solution as an answer. It could help future users.
Answer: I assume this is a change in behavior? You need to follow the path of this circuit to see where it loses power. Turn off the breaker and pull out the last fixture that has power and the first that doesn't. It might be something as simple as a receptacle that was wired with push-in connector that lost contact. I would pull any push-in (aka "backstabbed") receptacle connectors and wire to the screws instead.
Comment: With this kind of failure it is the last working outlet or the first non working outlet, it could be a bad connection on the hot or neutral your meter will measure the voltage where no real current will flow, turn on a big load and the circuit opens (very common with back stabs) also a nicked wire during install could have broken) I have found both but 98% of these type of failures in my experiance have been from back stabs, the push in connectors.
Comment: He already did that too what happened is turn tv on this morning and and then all living room outlets quit working then
Answer: First make sure against a known good source of power that the meter is working properly.  Then go back too the living room outlets and check both the above and below receptacle. Often times these type of receptacles are wired in what is called half hot configuration.  Half of the receptacle is full time hot, the other half is switched. The switched half was for floor or table lamps.  If you find half the duplex hot look for a near-by wall switch seemingly unused.  See if that doesn't turn on the other half of these receptacles?  P.
Comment: Done did all that and the meter is brand new and we checked it too with one working still no elec I in outlets in living room
Comment: And we changed the switch and the outlet to it too
Comment: And all is showing hot but not working


Transmission problems

Question: So I have a 2001 subaru legacy that was gifted to me with a destroyed throwout bearing. I replaced all of it except the flywheel cause it was in good condition. I had never drove a manual and learned with this car(I stalled alot getting the hang of it) and I'm pretty comfortable with it now. But the past couple days it hasn't been going into first gear or so it seems. When I put it in first at a stop the clutch doesn't have a (sweet spot) It moves but just creeps,shakes alot and is difficult to keep it running. It has been doing it intermittently sometimes going right in and other times it wont. Fluid is good, and master cylinder fluid(Dot 3) is full but brown, I need help figuring this out. I did notice that before this was happening second gear seemed like it moved alot more than usual, so much that the trim came off multiple times going into second. I've also noticed the past 2 days the shifter pretty much moves back to neutral after shifting to 2nd or 4th but stays in gear. Is that normal? Did I just happen to notice that cause I was having issues?
Is it possible I wore out the clutch or throwout bearing while learning how to drive it? Or possibly damaged the tranny? I have been riding the clutch alot in first cause it was the hardest for me. Recently I've smelt the burning clutch smell a couple of times trying to get it to engage in first,  and that never happened before while I was learning.
Comment: Welcome to Motor Vehicle Maintenance & Repair! From your description, it sure sounds like you've toasted the clutch. The last paragraph is telling.
Comment: Okay, Thank you. Wasn't sure if a clutch could go that quick even as a new driver.
Comment: @RichieRich You shouldn't fry a clutch learning how to drive a manual *correctly*, otherwise driving instructors would be need a new clutch in their car every week. But "riding the clutch a lot in first" (or any other gear) is *not* the correct way to use a manual transmission. With hindsight, paying for a few hours tuition would have been cheaper than paying for another clutch. (Except for starting from rest, it's quite possible to change gear with most manual transmissions without touching the clutch pedal at all - but don't try that until you can change gear "perfectly" the normal way!
Answer: It sounds as though you've "fried" your clutch. Riding the clutch (no matter the reason) introduces a LOT of heat into the clutch assembly. If enough heat is introduced into the flywheel and/or pressure plate, heat cracks can form. Heat cracks can actually raise the surface of the flywheel/pressure plate, which gives less space between them and the friction disk. This will make it harder to shift into gear while at a stop, because the clutch is not being allowed to disengage fully while the clutch pedal is depressed. In this scenario, it doesn't mean the friction disk is worn out, but rather that the flywheel/pressure plate are not performing as they are supposed to. Your saying you observed a "burning clutch smell" tells me you got it pretty hot. Considering you used your original flywheel and didn't resurface indicates the problem may be there.
Bottom line, I believe you are going to have to replace the clutch, or at a minimum, it's going to have to come out to observe what's going on with it. I don't believe you've done any damage to your transmission, though the synchros will take a bit more abuse while you are trying to shift it into gear.

Transmission problems