How do you show, through your narration, a hard and uncaring world?

Question: As I've already mentioned, I'm working on a sci-fi novel.
One of the main feelings that I wanted to represent when I started is the sense of a vast, empty, artificial world, mostly cold and uncaring of human life; the kind of impression you can have glancing at Tsutomu Nihei's landscapes in manga such as Blame! or Biomega.
Being inspired by his works, and other masters of the cyberpunk genre, I started to work on my novel. While I did manage to give out that feeling (according to some beta readers) I wonder if something could be done better, hence the question.
How do you show an hard and uncaring world?
How do you picture a stark contrast between the characters' struggle and an uncaring, hostile environment?
I'm mainly interested in stylistic devices (e.g. the use of certain images, similes, pairing up the character's internal emotion with a description of the outside world ...) that I could employ to make the difference even more clear cut.
Comment: I have some trouble with the word "uncaring" because no world "cares" about human life.  Some happen to be more supportive, some less, and some not at all, but in no case does the world "care".  Could you give me a different word?  By "world" is seems that you mean the physical location, but do you actually mean the other people are uncaring of each other?
Comment: @cmm You're right about the fact that the "world" doesn't care about human life. It's a personification. In many medias, movies in particular, wide shots of an harsh environment are used to portray the setting in a certain way. For example, in The Revenant with Leonardo di Caprio.
Answer: +1 to Ash, and I'd like to add another feature: lack of healthy life.
If you really want to show that an environment is hostile, show that nothing pleasant can thrive there. Here are some suggestions for describing a city.
Plants: No flowers (not even in window boxes). Any trees they might have planted are either dead or dying.
Animals: With the exception of rats and other vermin (the filth angle), keep to a minimum. A stray pigeon picking stale fries out of the garbage. Two scrawny strays fighting in an alley.
The residents themselves: Tired and stressed, possibly (or frequently) sick. They're always hurrying from place to place, never taking the time to slow down and enjoy their lives. They don't have much in the way of hobbies. It seems like all of their time goes into work and chores. Crime is common, the government is corrupt, and no one trusts the system.
It may also help to focus on the hard, lifeless, unfeeling surfaces: asphalt, concrete, brick, steel.
Comment: Nice, I hadn't thought of the "other life" part of the narrative, having read it it's obvious that I should have +1.
Comment: Nice tidbits about the residents.
Comment: This answer brings to mind the world that Fallout is set in.
Answer: This really depends on the type of world you have in mind. It isn't quite clear from your question whether you are talking about e.g. alien planets that are hostile to all life (toxic, radiated wastelands), or whether you are talking about a civilization that has become cold and uncaring (cyberpunk-style).
Since you want to know about stylistic devices you can use, here are some general ideas:

Short sentences without a lot of adjectives, except the ones that emphasize the struggle. "He looked around. No water in sight, only mirages produced by the scorching sun. He still knew better than to fall for these."
Usually mundane tasks like breathing and walking become vital, so mention them: "Inhale. Check the Geiger counter. Take a step forward. Exhale. Take another glance at the Geiger counter to be sure. Inhale again."
The previous example also uses repetition to emphasize the oppressive situation that the protagonist finds himself in.
Use verbs that evoke the hostility of the environment. Your characters don't breathe fresh air, they inhale this toxic atmosphere against better judgement because of the small amount of oxygen contained within. They don't blink (which is done easily and without thinking about it), they actively squint their eyes - it's an effort to do so. When they talk, they whisper with hoarse voices and they keep it extremely brief.
Since you mention an "artificial" world: You want to emphasize that this world was made, but that it was not made for human survival. Give an impression of what this artificial world is for, and how it fulfills its function, and how the human characters that find themselves on it are completely unimportant to its designs. "Whatever it was, it was working. The machines made a deafening high-pitch sound. But she could not see any seams in the metallic surface. No access points for maintenance, no signs that whoever built this was still around."
Answer: Some elements that can be clearly seen and described occur to me:

Graffiti is common where people feel disenfranchised, it seems to form an outlet for people who feel they don't have a voice.
Dirt, filth is omnipresent when people don't care for the environment and people around them. This can be noted in both people's appearance, dirt on their cloths or skin and in the environment with filthy buildings and uncollected garbage piled up in out of the way spaces.
Crowd dynamics, when people care for others crowds move smoothly around and through each other as everyone unconsciously gives way to each other and makes room. In a crowded and uncaring society people collide more often as each is going about their own business oblivious to those around them.

Certain words and turns of phrase also conjure up images of nastiness:

Harsh, particularly when applied to textures and colours.
Stark, when describing a contrast to better days, also when describing architecture, and also people where it is used as a synonym for severe.
Grimy, speaks for itself.
Sallow, when applied to both light and the appearance of people or colours.
Organic descriptions of inorganic structures, see China Mieville's descriptions of both New Crobuzon and Armada, make the [urban] environment seem to be crumbling and inimical towards the humans co-existing with it, if done right.

One other possibility is the inclusion of gangs in the narrative, not necessarily as players in the story but as an everyday part of the background life of the setting. Gangs are more prolific when, and where, people can't get ahead in life within the official, legal, framework of society.
Comment: @Liquid Yes is was teeming with life but it was also falling down around the ears of that life, the setting felt uncared for by and uncaring toward it's inhabitants.
Comment: New Crobuzon felt full of life to me (where my environment needs to be mostly devoid of it) but you're absolutely right that it is described as hostile.
Answer: These answers are all really good, so I'll just add a couple of things.

Imagine your setting as a character.  You've already personified it by making it "uncaring" and "hostile". Now, make it behave like an uncaring and hostile creature/character.  Your setting can interact with your characters just like they I react with it.  "As much as Mary was determined to survive, the wasteland was determined to kill her."

You can give your setting a backstory, mood, emotion, even motivation, all of which can contrast with that of your characters.

Make sure that your characters are seeing your world through all five senses.  It will help draw your readers in and help them experience your environment more thoroughly.  Your characters can see the wasteland and feel the burning sun,   but they can also smell the decay, taste sulphur in the air and hear metal against metal grinding in the distance.

This will also give you more material to contrast against your characters.  "Mary hummed 'You Are My Sunshine' to drown out the sound of metal grinding in the distance."
Answer: While the other answers are great and focus on tangible assets of the world, I'll try and find an answer that focuses instead on stylistic elements. I would say that a good way to get across apathy and an inorganic, unfeeling world would be to describe things in a cold, technical, repetitive and clinical manner. Eschew any flowery language when describing the architecture and surroundings, contrasting this with, say, how the narration describes their allies (if narration is associated with a character) or the heroes (if omniscient/detached).
For example, imagine we have a dingy undercity that's topped with affluent skyscrapers, we could use the aforementioned clinical style to render something like this:
The cleaning droids never reached the bottom of JunCorptropolis. The upper levels teemed with hygenic towers and hygenic cyborgs, the trust fund babies of CEOs. The toxic waste and grime, like most things, flowed downwards. The upper city did not seem to care about the structural unsoundness of its foundations.
Contrast this with, say, a rebel cubby-hole filled with friends of the protag:
Waylan entered the hideout to find what remained of the Undercity Banditos. Each of them styled themselves as though they were a canvas; colourful hair and tattoos were the order of the day. Fixing his tie, Waylan felt a tad overdressed. He took a seat on the makeshift couch and slipped off his jacket, when a smooth-skinned, pierced young woman spoke.
'So, how'd the undercover mission go?'
This will give a clear divide between the organic, passionate cause of the people you want the reader to relate to, compared to the apathetic world that obviously needs to be changed.
Answer: Uncaring. Harsh. Unforgiving. And a Sci-Fi setting? Well. It depends on what the deal is, but I'll offer some things I'd throw in to really show this world doesn't care for humans.

Alien world. The places looking for employees, so think bars, clothing stores, fast-food restaurants. "Humans need not apply." Put up signs outside showing humans aren't welcome in this establishment. Have some places house an atmosphere that humans can't breathe--nothing shows you're unwanted like the literal air you breathe being poisonous to you.
Policing. Again with aliens, but separate, yet related to, the above point. Have the authorities single out humans more often. Have a scene, or mention now and then when out in the world, of some human crying out "I didn't do anything!" and have the officers arresting them anyway. No reason, no lead up. Just arresting them.
Robot/cyborg world. Have tech needed to do that most basic thing. Lift (elevator) needs you to interact with the interface, but it needs a jack of some sort and humans just aren't equipped with that. I'd imagine there'd be some group of humans that would have some sort of workaround, but it's that they need it that's telling.
The pets have an innate dislike of humans, and have them be endemic of the setting. "You see that hairy bear-sized creature with razor sharp claws? That's Fido. He doesn't like your kind."
While being an uncaring world is one thing, a world that is super caring for everything that doesn't look like you is quite another. Show how beautiful the world is, and then show humans being treated like animals or worse.
You remember those mounted bears and deer in those old-fashioned lodges? What if these people mount humans? That certainly gives a clear impression of where humans stand here.
Answer: A hard, uncaring world is a matter of perspective.  If you're seeing it through the eyes of someone who loves it, it won't look bleak, no matter what the "objective" portrait of it might be.  So you want to start with a person who feels isolated, lonely, vulnerable, exposed and alienated, and then describe the landscape through his or her eyes.
Answer: There are two roads from Santa Fe to Taos, New Mexico. One runs through the gorge of the Colorado river. The other runs over the mountains through pine forests. The one through the pine forests is considered the scenic route.
I drove both routes a couple of years ago. I live in eastern Canada. Half our roads run through pine forests. I am heartily sick of looking at pointy trees. I did not find the high road scenic. None of our roads run through brilliantly colored sandstone canyons. I thought the main road was amazingly scenic.
But if you live in New Mexico, half of your roads run through brilliantly colored sandstone canyons. Very few of them run through trees. To them, no doubt, pointy trees are scenic.
In short, it is all about contrast. Juxtapose red with green. Juxtapose dry with wet. Juxtapose barren with lush. See the scene through the eyes on a character who comes from a place that is lush and green and wet and bountiful.
Answer: "Hard" i believe leans toward environment characteristics. Uncaring leans toward other intelligent beings that, as intelligent they should, but for some reason they don't care for other intelligent life beings, same kind or not.
You need to define such a setup to excuse both. Obviously you have the protagonist(s) and other actors. The environment is 'hard' for the protagonist and can be also hard for the other actors or not. The other actors are also uncaring towards the protagonist, and possible among them as well.
Obviously a good setup will answer both: An environment not really suitable for life explains both the term "hard world" naturally and the uncaring of other actors that live in that world; they look to survive not chat, help or share valuable resources with the protagonist.
Example of such setups would be:

A colonization starship lands at a not suitable enough planet for any reason.
A mining colony in an unfriendly without support due to civil war at the sponsors
A derelict but partially functioning habitat space station where all outlaws goather
A previously normal world after an apocalypse event


What do the different color bubbles in Tensorboard mean?

Question: I am using Tensorboard to find why my tensorflow model is not training properly.  The below graph shows three weights (W, W_1 and W_2).  W_1 and W_2 are initialized identically (as random_normal) with the exception of shape.  W_2 trains properly but W_1 does not train at all.  One is orange and the other is pink.  Does this suggest the problem and if so, can anyone tell me how to fix it?
Answer: Can you share the code for the initialization of your weights and biases?
The color codes in tensorboard are a useful place to start (since no code snippets have been provided).
Note that W and W_1 have one color and W_2, B, B_1 and B_2 have another color. This means they have been initialized differently. This can explain why you get different results for W_2 and W, W_1.
A recommendation would be to go back to the initialization of all weights and spot the difference in initialization. Good luck!
Comment: Hi @Tina_Iris W_1 and W_2 were initialized identically - they use the same initialization function, syntax (everything I can think of) with the exception of shape.  My question centers on what the colors mean since the colors of W_1 and W_2 are different and behave differently. I am hoping that the color legend for Tensorboard (if I could find one) would tell me something useful about how to debug.


Rigid Body stops at the upper surface of a hollow cube

Question: I am very new to blender and so forgive me if the question sounds vague. I am trying to create a scenario where I have a hollow bin with cloth on its edges and drop some objects into it (In Blender 2.8). I created the hollow bin by subdividing the default cube and deleting the upper face. later, I added a few planes with cloth simulations which will collide with the cube and rest on it. I have then animated the objects to fall into the cube at a frame where the clothes have settled in. In order to support the collision between the cloth and the active rigid body, I have added passive rigid body properties to the cloth. When I run the simulation, The active rigid body objects do not fall in the cube. Instead, they stop just above the cube and stay there until the simulation ends. I have made all the collision shapes as mesh.
Can someone please help me with the issue.
Answer: Possibly your bin needs solid walls and floor (using the Solidify modifier and recalculate outside normals) rather than a cube with upper face removed.
Answer: The first thing is, the cloth needs to be active if it is going to be deformed in anyway during your simulation.
The second thing is the result of the collision distance being too high. Finding and reducing that will decrease how far above the cloth the falling objects are when the collision is detected.......
Comment: Hi Jarrett. Thank you for the response. The said settings are already available. The cloth is always active and the margin of collision is the smallest value possible (0.001). I have added an image to show how the cloth simulation is working. This behaviour is as expected. The problem is, when I try to add an object (like another cube or some .stl files) and make it an active rigid body, it doesn't fall into the hollow bin and stops at the surface.


PhpDesigner 7, Box Shadow

Question: I am trying to use box shadow properties on PhpDesigner 7 and as soon as I enter the code, syntax such as box-shadow, it is giving me syntax error. Non of the box shadow codes is working in PhpDesigner 7.
I was wondering that does anyone have a solution for it and experienced this issue?
I don't want to switch to another IDE just for box shadow but I still need to use it for my website. Please advise me.
Thanks,
Sara
Answer: It's because phpDesigner currently don't support CSS3. Both CSS3 and HTML5 will soon be supported in phpDesigner.

PhpDesigner 7, Box Shadow


Android Studio Moto 360 Debugging

Question: I have followed the steps posted to debug over bluetooth here http://developer.android.com/training/wearables/apps/bt-debugging.html
but I do not know where to run the commands for adb, I am using mac and android studio version 1.5.1 with adb integration enabled.
No matter what I do, I can't seem to get my moto 360 to connect to the host. Any help would be appreciated thanks!
Answer: you can run adb command in a terminal of the system or terminal tab inside the Android Studio

Android Studio Moto 360 Debugging


Let OpenSSL decide which TLS protocol version is used by default

Question: I use Gem in a Box, a Ruby project that allows to create personal self-hosted gem repositories. Gem in a Box uses httpclient to connect to the gem repository. After reviewing my server's TLS setup in the aftermath of the OpenSSL heartbleed bug, I decided only to allow protocol versions of TLSv1 and higher on my server. A decision quite a few fellow administrators made too, because of security vulnerabilities in SSLv3 and below.
Now after I did this change, Gem in a Box refused to work with the following message:
OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server hello A: sslv3 alert handshake failure

I traced this problem back until I found the source in httpclient. Even though OpenSSL can find the best protocol version to use by itself, you set it only to use SSLv3 by default. I think this is a very bad idea and created a patch which lets OpenSSL do its own decision again by default.
As I am not so familiar with OpenSSL itself and the documentation of the Ruby binding is severely lacking I want to prevent introducing more problems than there were originally. Please review my changes and verify that it is doing what I intended.
It is quite hard to post the actual changes here because they are only meaningful if one knows the context. So now I will try to describe what I did:
httpclient has a class called SSLConfig which seems to produce helper objects to configure OpenSSL sockets. It sets some default configurations in its #initialize method. Originally it had the @ssl_version instance variable set to "SSLv3", When using the library an instance of SSLConfig is created and its #set_context method is called which applies the aforementioned defaults onto an instance of OpenSSL::SSL::SSLContext, which afterwards seems to be used to create OpenSSL sockets.
I now changed to initial value of @ssl_version to the symbol :auto and modified the #set_context method to only set the actual value of @ssl_version to the SSLContext object, if its value is not :auto.
Manual testing so far resulted in the exact effect I wanted to achieve.

Here's a link to the official GitHub repository of the httpclient library.
See my full commit on GitHub for the mentioned changes.
I also made a pull request to the original project.

Here are some relevant snippets from lib/httpclient/ssl_config.rb:
class SSLConfig

  ...

  # Which TLS protocol version (also called method) will be used. Defaults
  # to :auto which means that OpenSSL decides (In my tests this resulted
  # with always the highest available protocol being used).
  #
  # See the content of OpenSSL::SSL::SSLContext::METHODS for a list of
  # available versions in your specific Ruby environment.
  attr_reader :ssl_version

  ...

  # Creates a SSLConfig.
  def initialize(client)
    return unless SSLEnabled
    @client = client
    @cert_store = X509::Store.new
    @client_cert = @client_key = @client_ca = nil
    @verify_mode = SSL::VERIFY_PEER | SSL::VERIFY_FAIL_IF_NO_PEER_CERT
    @verify_depth = nil
    @verify_callback = nil
    @dest = nil
    @timeout = nil
    @ssl_version = :auto
    @options = defined?(SSL::OP_ALL) ? SSL::OP_ALL | SSL::OP_NO_SSLv2 : nil
    # OpenSSL 0.9.8 default: "ALL:!ADH:!LOW:!EXP:!MD5:+SSLv2:@STRENGTH"
    @ciphers = "ALL:!aNULL:!eNULL:!SSLv2" # OpenSSL >1.0.0 default
    @cacerts_loaded = false
  end

  ...

  # interfaces for SSLSocketWrap.
  def set_context(ctx) # :nodoc:
    load_trust_ca unless @cacerts_loaded
    @cacerts_loaded = true
    # Verification: Use Store#verify_callback instead of SSLContext#verify*?
    ctx.cert_store = @cert_store
    ctx.verify_mode = @verify_mode
    ctx.verify_depth = @verify_depth if @verify_depth
    ctx.verify_callback = @verify_callback || method(:default_verify_callback)
    # SSL config
    ctx.cert = @client_cert
    ctx.key = @client_key
    ctx.client_ca = @client_ca
    ctx.timeout = @timeout
    ctx.options = @options
    ctx.ciphers = @ciphers
    ctx.ssl_version = @ssl_version unless @ssl_version == :auto
  end

  ...

end

Here's what is using the #set_context method in lib/httpclient/session.rb:
...

def create_openssl_socket(socket)
  ssl_socket = nil
  if OpenSSL::SSL.const_defined?("SSLContext")
    ctx = OpenSSL::SSL::SSLContext.new
    @context.set_context(ctx)
    ssl_socket = OpenSSL::SSL::SSLSocket.new(socket, ctx)
  else
    ssl_socket = OpenSSL::SSL::SSLSocket.new(socket)
    @context.set_context(ssl_socket)
  end
  ssl_socket
end

...

Answer: I've got a few things to say about the code, but having looked at the diff:
-      @ssl_version = "SSLv3"
+      @ssl_version = :auto

and:
-      ctx.ssl_version = @ssl_version
+      ctx.ssl_version = @ssl_version unless @ssl_version == :auto

your code changes seem minimal, and to the point doing exactly what they are supposed to do, and nothing more.
What I think you should add are the tests to show your changes, and make sure no-one will break your code in the future.


Job change after 6 months

Question: I have been at a startup for 6 months. It is a toxic work environment. I am planning to switch jobs. I have not switched jobs so early. I had been at my previous company for 4 years. Will there be a problem in switching jobs?
Comment: Related: [How can one resign from a new job gracefully?](https://workplace.stackexchange.com/q/7149)
Answer: In general there should be no problem as long as you do not change jobs very often and you can explain why you changed after a few months.
I have similar experiences: Stayed at one job for several years, felt it was time for new challanges and found myself at a job that did not fit the description and where literally not one single employee was comfortable working at.
Of course the question came up in my interview. In my experience a very good answer is:

The work environment at my current employer feels toxic to me and a lot of my colleagues expressed similar oppinions or have already left the company. I really wish to find a workplace where I feel comfortable enough to stay for at least the next few years.

That way you explain the reason for changing after such a short time and at the same time commit yourself to your possible next employer.
Answer: I don't see an issue as long as you provide a good answer when you are asked and it's likely you will be.
If asked be honest to the interviewer about why and that should be fine. You also have the proof on your CV that you can remain a loyal employee.
If you are not happy in your work environment there is nothing wrong with changing it. If employers don't respect that then perhaps it's not the place to work.
Having been through similar experiences in the past and having roles really affect my mental health I would never stay somewhere for time on my CV if I'm not happy.

Job change after 6 months


Where is the shader packs folder on Mac?

Question: I had downloaded some shader packs before, but now I can't find my shader packs folder. I am on a Mac.
Comment: The easiest method would be: Open the resource packs folder inside of Minecraft itself, go up one folder and look for `shaderpacks`. If you are using Optifine's shader implementation, it even offers a shader pack folder button to click on.
Answer: The shader packs folder on a Mac is ~/library/application support/minecraft/shaderpacks. (~ stands for your user folder and will be automatically replaced with your userfolder when using ⇧+⌘+G)
However, you can also get to the shader packs folder by going to Options... > Video Settings... --> Shaders... --> Open shader packs folder.


A condition on commutator implies quantization of field

Question: The canonical quantization procedure requires pairs of conjugate dynamical variables to be identified, which, after quantization, become operators whose commutator is $i\hbar$. How does the second quantization work? I mean just imposing a condition on the commutator leads to quantization of field, what is the underlying magic behind this prescription?
Comment: What do you mean by "the sceond quantization"? There's the "good" meaning as explained in [this answer](http://physics.stackexchange.com/a/187106/50583), and there's a "bad" meaning where people use second quantization to just mean the process of quantizing a classical field theory (as opposed to the classical particle theories for QM).
Comment: *First quantization is a mystery, but second quantization is a functor [cit. E. Nelson].* Apart from the suggestive quotes, all that you need is a real vector space with a non-degenerate antisymmetric bilinear form on it, and then you have a prescription on how to relate it to a C* algebra of quantum observables that encodes the canonical commutation relations (the so-called Weyl C* algebra).
Answer: When you have a commutator of the form, $[A,B]=i\hbar$, you can relate this to $[x,p]= [-p,x]=i\hbar$. So, as $p=\frac{\hbar}{i}\frac{\partial}{\partial x}$ you can write $B = \frac{\hbar}{i}\frac{\partial}{\partial A}$ or $-A=\frac{\hbar}{i}\frac{\partial}{\partial B}$ and proceede with the calculation of states as in ordinary quantum mechanics using your energy expression as the Hamiltonian.
Comment: Roughly speaking, this is only true in quantum mechanics, not in quantum field theory.
Comment: I have seen that comparision often given in text books. But it seems to me very casual.  I believe there has to be some more fundamental reason.
Comment: This is the fundamental reasoning. Remember that quantum mechanics began with Heisenberg's matrices that obeyed this commutation relation. The calculation of the  harmonic oscillator states and energies can be performed algebraically starting from the commutation relation. Pauli was able to calculate the hydrogen states  as well. The instantiation of the commutation relation that is consistent with the Schrödinger equation is the one I described in my answer. More generally one might change p to p +f(x).
Comment: I am not pleased to get my answer downvoted. I have used my time to help somebody by sharing my quite deep insights in this matter. Authors of QFT textbooks tend to not delve into this which  might be a mistake.
Comment: yuggib there is no mathematically satisfying formulation of QFT, so we only have recipes. However, the recipes give a consistent description of the physics. The recipes can be understood by making analogies with QM. C* algebras haven't really solved things.


How do I make concrete out of mortar?

Question: I need white concrete for a countertop sample, but the only white concrete-like product is white mortar. If I just add an equal sized bag of gravel to the mortar, will it be close enough to use as concrete? If not, what else do I need to add, and at what proportions?
Comment: You can't find "white portland cement" anywhere?  Mortar typically has sand and will not give a smooth surface.
Comment: @JPhi1618, mortar can be finished smooth with techniques similar to making concrete smooth; tamp and smooth with metal trowel to bring water up to the surface, giving a final smooth trowel job with metal float.
Comment: What type of mortar?  Type S?  Thinset?
Comment: It looks like the available white mortars are thinset. I did end up special ordering white portland cement to make the concrete thanks to all these comments and responses.
Answer: Mortar is similar to concrete in that they both contain Portland cement and sand. The 2 different ingredients are that mortar has hydrated lime and concrete has larger aggregates (stones). Using mortar in place of concrete isn't a good idea as the two have dissimilar compressive strengths. If you are only able to use the white mortar you may be able to make it concrete-like by adding a shovel full of Portland cement and than mix (1) shovel of gravel with (2) shovels of plaster sand and (1) shovel of mortar. The added Portland cement and sand may produce a strong enough mix, but the mortars' hydrated lime is the weak link. As been commented on, it may be easier to seek-out a pre-mixed white cement if possible and use dye for a brighter color. Look for concrete dye at your local building supply store. They should have several colors available including white. A pint is the typical liquid amount. Depending on the shade of white you desire (brilliant down to greyish white) you may need several pints. You will have to experiment with proportions to get the right shade of white, but as was pointed out in comments you may be using more dye than is cost effective if you want a "white" white.
Comment: Back in the day, to make cement, the proportions were 1 shovel portland cement, 2 shovels sand and 3 shovels washed gravel. If I remember right masonry cement (mortar) is different by not just the lack of gravel, but it has limestone added to it too. It would be difficult to "unmake it" concrete.
Comment: Have you used the white "dye" with grey concrete?  I'd be surprised if you could get anything lighter than "greyish white", but my only experience is mixing paint...
Comment: Thank-you both for your comments. I have edited my answer to reflect your suggestions.
Comment: Not *all* mortars are the same as concrete!

How do I make concrete out of mortar?


Hiring overseas UX profesional to aid our product design process

Question: For example, you have a product that has been run in a specific country then your CEO wants you to expand the market to another country with a different culture and language. Do you think it's wise to create a specialized product to cater to the market in the new country? if so, how does it feels to partnering to local UX team/agency/professional to help your design process? especially the user research and maybe usability testing.
Answer: If we're talking solely about UX work then there are advantages and disadvantages to having people from another culture.
I work for US companies and I've worked with agencies who've brought in consultants from around the world (Australian, Indian, Russian and Swedish). The quality of the UX work was not dependent on the country of origin.
The advantage is a different perspective - an instance where they find something to be new or different and point that out. The only disadvantage I've found are time zone constraints when they return to their home country. (It's unrealistic to ask people to relocate for 6-12 months for a project.
So, to answer your question, a good UX person can transition to another country. The one real lack, if there is one, will be the ability to help with labeling, and other copy writing based work.
Answer:
Do you think it's wise to create a specialized product to cater to the market in the new country?

You have the resources to create a new product from scratch despite the language and cultural barriers? I'd think it preferable to adapt the existing product, primarily via translations. Then going forward, try to create unified experiences that work well regardless of language.

... how does it feels to partnering to local UX team/agency/professional to help your design process?

Since operating systems use pretty much the same interfaces world-wide, the main issues should be ensuring appropriate translations and understandable iconography. Having multi-lingual and native teams work on those issues should be invaluable.
Answer: I can see value in having a UX professional from the country you are planning to target, but the real need is to be sure and do UX testing with users from that country.
You could hire a UX team on site, either from your country or the other one or a mix of both. You could also conduct online/remote user testing. Either way, I do think it is important to test your product with users from the target country. Then you will not be guessing at their pain-points and goals.
https://www.nngroup.com/articles/cultural-nuances/


Using induction to prove $3$ divides $\left \lfloor\left(\frac {7+\sqrt {37}}{2}\right)^n \right\rfloor$

Question: How can I use induction to prove that $$\left \lfloor\left(\cfrac {7+\sqrt {37}}{2}\right)^n \right\rfloor$$ is divisible by $3$ for every natural number $n$?
Comment: Hint: Note that $0<\alpha=\cfrac{7-\sqrt{37}}{2}<1$ - can you use this to construct a recurrence relation which has a solution of the form $\alpha^n+\beta^n$ and base your induction on that.
Answer: Since
$$
\left(x-\frac{7+\sqrt{37}}2\right)\left(x-\frac{7-\sqrt{37}}2\right)=\left(x-\frac72\right)^2-\frac{37}4=x^2-7x+3\;,
$$
the recurrence relation
$$x_n=7x_{n-1}-3x_{n-2}$$
has solutions
$$
x_n=c_1\left(\frac{7+\sqrt{37}}2\right)^n+c_2\left(\frac{7-\sqrt{37}}2\right)^n\;.
$$
With $c_1=c_2=1$ we have $x_0=2$ and $x_1=7$. Since $0\lt\frac{7-\sqrt{37}}2\lt1$ and $x_n$ is an integer,
$$
\left\lfloor\left(\frac{7+\sqrt{37}}2\right)^n\right\rfloor=x_n-1\;.
$$
Now you just need to use the recurrence relation to show that the property that $x_1$ has remainder $1$ mod $3$ is inherited by the remaining terms.
Comment: Was just re-reading this, and shouldn't that be $$\left\lfloor\left(\frac{7+\sqrt{37}}2\right)^n\right\rfloor=x_n-1$$?
Comment: @Thomas: Thanks -- indeed, it should; and that $x_1$ has remainder $2$ mod $3$ was even more blatantly wrong.
Answer: Consider the recurrence given by
$$x_{n+1} = 7x_n - 3 x_{n-1}$$ where $x_0 = 2$, $x_1  = 7$.
Note that $$x_{n+1} \equiv (7x_n - 3 x_{n-1}) \pmod{3} \equiv (x_n + 3(2x_n - x_{n-1})) \pmod{3} \equiv x_n \pmod{3}$$
Since $x_1 \equiv 1 \pmod{3}$, we have that $x_n \equiv 1 \pmod{n}$. Ths solution to this recurrence is given by
$$x_n = \left( \dfrac{7+\sqrt{37}}{2} \right)^n + \left( \dfrac{7-\sqrt{37}}{2}\right)^n \equiv 1 \pmod{3}$$
Further, $0 < \dfrac{7-\sqrt{37}}{2} < 1$. This means $$3M < \left( \dfrac{7+\sqrt{37}}{2} \right)^n < 3M+1$$ where $M \in \mathbb{Z}$. Hence, we have that
$$3 \text{ divides }\left \lfloor \left (\dfrac{7+\sqrt{37}}{2}\right)^n \right \rfloor$$
Answer: Let $a=\dfrac{7+\sqrt{37}}{2}$, and $b=\dfrac{7-\sqrt{37}}{2}$.  We first show that $a^n+b^n$ is always an integer.
We have
$$a^{n+1}+b^{n+1}=(a+b)(a^n+b^n)-ab(a^{n-1}+b^{n-1})=7(a^n+b^n)-3(a^{n-1}+b^{n-1}).\tag{$1$}$$
It is easy to check that $a^0+b^0$ and $a^1+b^1$ are integers. The others are dealt with by induction using Equation $(1)$.
Note that $b\lt 1/2$, and $b$ is positive. Since $a^n+b^n$ is an integer, it follows that $\lfloor a^n\rfloor=a^n+b^n-1$.
So we want to prove that $a^n+b^n\equiv 1\pmod{3}$. This is true for $n=0$ and $n=1$. Now from Equation $(1)$, on the assumption that $a^n+b^n \equiv 1\pmod{3}$, we obtain that $a^{n+1}+b^{n+1}\equiv 1\pmod{3}$.
Answer: Hint: $$a_n = \left(\frac{7+\sqrt{37}}{2}\right)^n + \left(\frac{7-\sqrt{37}}{2}\right)^n$$
is always an integer, and there is a recurrence relation for $a_n$.  Since $0<\frac{7-\sqrt{37}}2<1$, you want to show that $a_n-1$ is divisble by $3$. Prove it by working out the recurrence relationship and use induction.
This result can be generalized. For integers $n>0$ and $d>0$:
$$\left\lfloor\left(\frac{2d+1+\sqrt{4d^2+1}}2\right)^n\right\rfloor$$
is divisible by $d$.


Jackknife vs. LOOCV

Question: Is there really any difference between the jackknife and leave one out cross validation? The procedure seems identical am I missing something?
Answer: Jackknife often refers to 2 related but different processes, both of which rely on a leave-one-out approach -- leading to this very confusion.
In one context, jackknife can be used to estimate population parameters and their standards errors.  For example, to use a jackknife approach to estimate the slope and intercept of a simple regression model one would:

Estimate the slope and intercept using all available data.
Leave out 1 observation and estimate the slope and intercept (also known as the "partial estimate" of the coefficients).
Calculate the difference between the "partial estimate" and the "all data" estimate of the slope and the intercept (also know as the "pseudo value" of the coefficients).
Repeat steps 2 & 3 for the entire data set.
Compute the mean of the pseudo values for each coefficient -- these are the jackknife estimates of the slope and intercept

The pseudo values and the jackknife estimates of the coefficients can also be used to determine the standard errors and thus confidence intervals. Typically this approach gives wider confidence intervals for the coefficients because it's a better, more conservative, measure of uncertainty. Also, this approach can be used to get a jackknife estimate of bias for the coefficients too.
In the other context, jackknife is used to evaluate model performance.  In this case jackknife = leave-one-out cross validation.  Both refer to leaving one observation out of the calibration data set, recalibrating the model, and predicting the observation that was left out.  Essentially, each observation is being predicted using its "partial estimates" of the predictors.
Here's a nice little write-up about jackknife I found online:
https://www.utdallas.edu/~herve/abdi-Jackknife2010-pretty.pdf
Comment: I was just separating the ideas of estimating parameters using LOO versus estimating the value that was left out (as in LOOCV). I see them as two related but slightly different processes, but perhaps both can be referred to as LOOCV? I could also be mistaken.
Comment: Unless I am mistaken (and I may well be), your first context describes leave-one-out *cross validation*.
Answer: In cross-validation you compute a statistic on the left-out sample(s). Most often, you predict the left-out sample(s) by a model built on the kept samples. In jackknifing, you compute a statistic from the kept samples only.
Comment: I do not understand how this answer speaks to the LOOCV in the original question. In what sense can one "compute a statistic" on a *single* left-out observation?
Comment: @paperskilltrees LOOCV means that **leave one observation out** for each observation in turn, calculate the relevant stats on the remaining observations, and average results across $N$. If  I have a sample of size $N$, the statistics are not calculated on the single **left out** observation in each step, but on the $N - 1$ remaining observations; those $N-1$ observations are not, in any sense, left out.
Comment: @Alexis Thanks, this is precisely what I thought you meant.
Comment: @Alexis I am trying to understand your comment. I am confident that Tommy L meant training a model $y(x)$ based on all-but-one subsample $\mathcal{D}_\bar{i} := \mathcal{D}\setminus \{x_i\}$ and evaluating the prediction on the left-out datapoint $x_i$. Were you pointing out that $\hat y(x_i;\mathcal{D}_\bar{i})$, as a statistic, depends on all datapoints and not just $x_i$?

Jackknife vs. LOOCV


Yank the first word from each line in vim

Question: I'm using vim and I'd like to copy the first word for a range of consecutive lines. The only thing that I could think of is :4,32yw (for lines 4-32), but it didn't work. Any help is appreciated in advance, thanks!
Answer: You can do it, but it might be a little bit more complicated than using a simple command as you did.
What you tried to run, is normal mode commands as execute commands. That won't work as you did it. Commands in the normal mode (like pressing yw) won't work  es ex-commands.

To run the normal mode commands in the ex-command mode, you should use the normal command (for more information, you can see :help normal).
However, even if you would change you command to use the normal mode command (something like :4,32 normal! yw) it would still not work, since this would run for every line, each time running over the previous yanked value.
You can do the desired action, using a vim register that would append the word in each loop (for more info about registers you can read :help registers).

To do it, you should change the command to be something like :3,32 normal! ^"Ayw.
To break down this command:

: - enter ex-command mode.
3,32 - The range to run the command over.
normal! - The actual command to run. Run it without any custom mapping, to avoid mappings that run over the wanted action.
^ - Go to the start of the line.
"A - Run the yank into the a register, appending the data to the previously saved data in it.
yw - Yank the current word.

Later, to print the copied values, you should use "ap (in the normal mode) at the desired location.
Drawbacks
Note that the command inserts the new word into the registers, ignoring the first value of the register. It means that if the register wasn't empty once you run this command, all the words would be appended to the current value of the register.
To clear the previous value of the register, you can run the command:
:let @a=''

before running you yank command.
Automation
In case you want to do it many times, you might want to use a simple function that would do it all for you, instead make you run both commands every time.

A simple function that would do this:
function! CopyFirst(register) range
    execute "let @" . a:register. "=''"
    execute a:firstline . "," . a:lastline . "normal! ^\"" . toupper(a:register) . "yw"
endfunction

Usage:
:3, 32 call Copyfirst('a')
"ap

Answer: This function uses a function range (more info of this feature in :help func-range):
" Get the first word of the line for a given range of lines
function! GetFirstWord() range
    let @a=""
    execute a:firstline.",".a:lastline."g/.*/y A"
    echo split(substitute(@a," *\\(\\w\\+\\).\\{-}\\n","\\1 ","g"))
endfunction

The first line cleans register a. Second line yanks the lines inside the range into register a. The last line prints a List with the first words of each line. Sample input file:
some sample
   text abc
   123 456
function
yy xx

Sample calling and output:
:2,4call GetFirstWord()
['text', '123', 'function']


What are the best free online resources to learn Drunken Kung Fu style?

Question: Can a weak person learn kung fu? I want to master drunken style. I am fascinated with it. What are the basis of it? and are there any free online resources to learn it?
Comment: You have three questions in there. The first two can easily be answered by a quick Google search. The last one is asking about a list of resources which we do not handle well. There are a few questions about solo learning you should check out.
Answer: Drunken kungfu is crazy difficult. It requires significantly higher levels of timing, balance and coordination than most other styles. It may look foolish and easy, but it takes alot of skills to make it look that foolish and easy.
My suggestion is to start with another style first. Once you get the hang of basic stances and your coordination improves, maybe you can talk to your teacher about drunken kungfu. But really, start at the beginning. You don't polevault without being able to run and jump, first.
Comment: what are some resources for free to learn kung fu online?
Answer: Learning martial arts online is not a great option. You will need live instruction, which you can then supplement with online instruction. You will also need to live spar, a lot. Hitting pads and bags can only go so far. You need a resisting opponent to determine if your stuff will actually work, and to improve it.
Stop in to your local MMA gym and see what they have to offer. Most will have Boxing, Muay Thai, Dutch Kickboxing, Brazilian Jiu Jitsu, and Wrestling. All great options if you're interested in learning to fight.
Comment: @SeanDuggan OP called himself a "weak person". I would hate to see some nonathletic guy throwing YouTube kung fu kicks in their bedroom and think they magically know how to fight. The best way to learn what works in the real world is to just do it. MMA is the closest rule set to real life that you can spar with and not have anyone die. So yes, I avoided the style he brought up, but only because it's extremely dangerous to believe in one's own fighting ability without rigorously testing that ability. If OP is strictly doing it for fun, and not fighting ability/self defense, have at it!
Comment: I'll admit that I'm a bit iffy on the answer. On one hand, the first part is good, that you really need to learn with other people. The latter part feels like "But instead of that style, check out my style because it's better."


Is the serum concentration of calcitriol different at different times in the day?

Question: Given that calcitriol has a relatively short half-life in adults it would be possible that the serum concentration is at different times of the day different if it gets produced in different quantities at different times of the day.
Is this the case or is the level relatively constant over the day and doesn't follow a daily rhythm?
Answer: Calcitriol, or 1,25-dihydroxyvitamin D, is produced in the kidney by 25-hydroxyvitamin D-1α-hydroxylase from it's precursor, 25-hydroxyvitamin D.
Calcitriol has a plasma half life of about 6 hours. It is tightly regulated. This regulation involves a negative feedback loop on its own synthesis and via an inhibitory effect on PTH synthesis, and control by downstream effects (plasma phosphorus, calcium, FGF-23 and others).
25-OH-D, the precursor, has a plasma half life of about 2-3 weeks, and except in chronic deficiency or other pathologic states, is in plenty of supply for the appropriate production of calcitriol. Because of this, it is unlikely that, for example, daily changes in sun exposure or nutritional intake would propagate down to production of the active metabolite.

The image and a good review of Vitamin D can be found in this NEJM article
References ranges at my lab and in Lange's guide to diagnostic tests do not include any interpretation suggestions for plasma or serum 1, 25-dihydroxy vitamin D (calcitriol) at different times of day. Notably, though, this test is not often done clinically. It's primarily for the case where a patient has high calcium, low PTH, and no malignancy has been found.
Despite this (reference ranges do not distinguish between times of day), there may be a circadian rhythm within that range. Regulators and downstream effects of calcitriol do show a circadian rhythm, as is demonstrated in this classic 1972 study:
Comment: Is the tl;dr: We don't really know, both are plausible?
Comment: @Christian tl;dr: it isn't relevant for interpreting clinical values, but it is plausible (likely?) that there is some circadian variation.
Comment: @Christian I'd be surprised to *not* see some regular variation, along with those calcium, PTH, and phosphate levels.


Fixing Liftup Hydrolic Support Bar

Question: I have 4 cabinet door having same issue. They are not working as powerful anymore and I need to keep the door to lift up instead of these bars. While they seem very basic devices, is there a way to fix these liftup support bars or do I have to throw them to wastebasket ?
Comment: I definitely don't know how to make it works better but I found a super nice article that explain how it works [Click here](https://www.explainthatstuff.com/gassprings.html). I hope this may help you. **How a gas spring works:** [![enter image description here](https://i.stack.imgur.com/fhO8s.gif)](https://i.stack.imgur.com/fhO8s.gif) **How a gas spring generates a force:** [![enter image description here](https://i.stack.imgur.com/PagLq.png)](https://i.stack.imgur.com/PagLq.png)
Answer: The pictures are not enough to understand how they are built. I recommend you to analyze them as verify if they have anything that looks like "adjustable something". Maybe there is a ring that you can rotate, maybe some screw, or any other detail.
Another idea would be to find the brand and model, and then look on the internet for instructions how to adjust them.
However, be prepared to the outcome that they are cheap bastards (they usually are) and that there is nothing you can do about it. I mean, besides buying and installing new ones.

Some easy hack
Move the lower end and / or the upper towards the hinge. In this way, you will have the effect that you desire.  Looking at the detail of the piston / bar, all you need to do is to unscrew a little the screws, move the end, screw again.
If the movement is no longer possible because the screw is at the limit, just apply the screw to a new position closer to the hinge and then adjust.
This operation will require some trial and error, but should not be difficult at all.
Comment: excellent. I am glad I could help :)
Comment: as you said they are so shcep; I changed the old one with new one with the price of 1$

Fixing Liftup Hydrolic Support Bar


When to use concrete plasticizer

Question: When should one use a concrete plasticizer? Should it be used for internal floor slab?
Comment: I have only seen plasticiser used when pumping concrete. I believe it increases the slump with out adding water.
Answer: You use plasticiser when you need to improve the workability of concrete.
Concrete's workability improves as you add increasing amounts of water. Increasing the amount of water in the mix beyond the optimum leads to weaker concrete. Insufficient water also makes concrete weaker, as it is harder to compact it to remove air voids.
For a normal floor slab, I wouldn't expect to need plasticiser to get the concrete sufficiently workable.

When to use concrete plasticizer


Is "pls" considered unprofessional?

Question: Any where I talk to people on messages, emails, chats, etc... I find people tend to use the word "pls" instead of "please". Even my phone company texts me automatically saying "Pls call 321, You have 7 New VoiceMail messages". In business emails as well I am hearing this word. I find it unprofessional but is it just me who feels this way and should I use this or not for important emails and work?
Comment: Appropriate for informal contexts, particularly text messages where abbreviations are often used. Inappropriate for formal communications such as a job application or a written proposal.
Comment: Useful and acceptable if you have limited characters (e.g. text message, comment on SE, telegram?), but if character count is unlimited, using unnecessary abbreviations implies the writer doesn't have time for the reader (or is typing on their handheld device, but you can set up short cuts on those, too). That can be considered unprofessional or even rude... but [Hanlon's razor](https://en.wikipedia.org/wiki/Hanlon%27s_razor) and all...
Comment: Welcome to EL&U. Stack Exchange is not well-suited to solicitations for opinions, and there is no single authority on what is or isn't considered professional in all circumstances for all English speakers all around the world. I strongly encourage you to take the site [tour] and review the [help] for a better understanding of the kinds of questions we can handle here.
Comment: Pam is right on the money here. "Pls" is saying the exact opposite of "please". It shows disrespect to the person you are talking to, and communicates that you don't actually care for the thing you ask them for. Like, you can't even be arsed to type three more letters, that's how little you care about the thing or the person. And yes, if space is an issue, "pls" is certainly better than nothing at all, but even then, "please" is still much better. And also space is not an issue, like, ever. It's three letters. You have that space. You absolutely always do.
Answer: pls

abbreviation for please.  (used in e-mails and text messages)

macmillan
As this is an abbreviation for please, use accordingly. Many feel it should not be used formally.  RSVP
(abbreviation for répondez s'il vous plaît) is an abbreviation too, yet is found in formal and informal correspondence.

Is "pls" considered unprofessional?


How does the amount of Calcium Carbonate in blackboard chalk influence its quality

Question: Does the amount of calcium carbonate in chalk influence its charecteristics ?
If so please mention them
Comment: Welcome to the chemistry site of the SE network.

The site expects that you write explicit compact summary of your prior effort to answer the question, based on your knowledge and on searching for existing related  info or answers. It would prevent others to tell you what you already know or what you could easily find yourself.

Effort not shown can be considered as effort not done and such a question may be  closed.  [How do I ask a good question?](https://chemistry.stackexchange.com/help/how-to-ask).
Answer: Amorphous pure calcium carbonate $\ce{CaCO3}$ is a white, common and rather soft mineral, called chalk or lime. It can be cut down in cylinders as thick as a finger. Using it on a blackboard will make a broad and thick line, and your fingers (and trousers) will quickly be full of white marks. It is too soft to be useful in a classroom. On the other hand, the same cylindrical pieces can also be made with plaster, which is hydrated calcium sulfate. But the obtained piece is too hard to be used on a blackboard. It will scratch the board. But if you make the appropriate mixture of plaster and lime, you can produce a piece of chalk useful on a blackboard.
So to produce a piece of chalk useful in a classroom, lime is reduced to powder, mixed with plaster ($\ce{CaSO4·\frac{1}{2} H2O}$). The mixture is then got wet. This will transform the plaster $\ce{CaSO4·\frac{1}{2}H2O}$ into gypsum $\ce{CaSO4·2H2O}$. This operation also transforms the mixture of two powders into a solid block, ready to be used for writing on a blackboard. Neither too soft, nor too hard.


time taken to complete work

Question: A can do a piece of work four hours faster than B. They worked together for two hours and then the remaining part of the work was done by A in an hour. How many hours would B take to complete the job if he were to work alone?
Answer: Hint:  let $a$ be the fraction of the job that $A$ can do in one hour and $b$ be the fraction that $B$ can do in one hour.  Write two equations that express the first two sentences of your problem.  You have two simultaneous equations in two unknowns, so solve them.  Your answer is then $\frac 1b$
Answer: let t be the time A takes in hours, then A does $\frac{1}{t}$ per hour. B does $\frac{1}{t+4}$ per hour. we know $\frac{3}{t}+\frac{2}{t+4}=1$ $\rightarrow 3+\frac{2t}{t+4}=t\rightarrow 3(t+4)+2t=t^2+4t\rightarrow t^2-t-12=0\rightarrow (t-4)(t+3)=0$ so $t=4$
therefore A takes 4 hours and B takes 8 hours.
Comment: No, B does $\frac 1{t+4}$ per hour.
Comment: there is a little error in the explanation above.Nevertheless,i have understood the method to be used to arrive at the answer.

time taken to complete work


canonical bundle of relative Grassmannian

Question: Let $X$ be a smooth projective variety and $\mathcal{E}$ a locally free sheaf of rank $r$ on it. Now we consider the relative Grassmannian $\mathrm{Grass}_X(l,\mathcal{E})$. What is the canonical bundle of the relative Grassmannian?
Answer: If you know the calculation of the canonical bundle of the usual Grassmannian (nice writeup here), you can adapt it directly to the relative situation. The result is that $K_G=\mathcal O_{\mathbf P}(-r)_{|G}$, where $\mathbf P=\mathbf P_X \left( \bigwedge^l \mathcal E \right)$ is the projective bundle into which the relative Grassmannian is embedded by the Plücker embedding.
Answer: Let $\pi:Grass(\mathcal{E})\rightarrow X$ be the projection, and $\mathbf{q}:\pi^*\mathcal{E}\twoheadrightarrow \mathcal{Q}$ the universal quotient rank $l$ quotient. One has an exact sequence
$0\rightarrow T_{G/X}\rightarrow T_{G}\rightarrow \pi^* T_{X}\rightarrow 0$.
Since the tangent space to the ordinary Grassmannian at a point $q:\mathbb{C}^n\twoheadrightarrow Q$ is $\text{Hom}(\ker q, Q)$, one finds that the relative tangent bundle $T_{G/X}$ is isomorphic to $\underline{Hom}(\ker\mathbf{q},\mathcal{Q})$. Now the exact sequence above allows us to express $\det T_G=K_G^{-1}$ as the tensor product of the determinants of the left and right guys in the sequence. Since $\det T_{X/G}=(\det\ker\mathbf{q})^{-l}\otimes(\det\mathcal{Q})^{r-l}$, we get an explicit formula for the canonical bundle on $G$ in terms of $K_X$ and the tautological bundles on the Grassmannian.
Note that in the case where $\det\mathcal{E}=\mathcal{O}$ one has an $\det\ker\mathbf{q}^{-1}=\det\mathcal{Q}$, so that one obtains $\det T_{G/X}=(\det\mathcal{Q})^r$. In other words, in terms of the Plucker embedding, $\det T_{G/X}=\mathcal{O}_G(r)$. In this special case, the relative canonical bundle is what was given in the previous answer.


Solspace Freeform Pro - How to pull URL title into the email subject

Question: I am using Solspace Pro form on my website and I have no clue on how to change the subject of the email. I will be glad to know if there is a way to pull the title of a detailed page of a listing into the email subject.
When a form on a detailed page is filled, I want to pull the title of that detailed page into the subject of the email when notification is sent.
Answer: The Subject is set under the Notifications tab. There you will see a list of your notifications templates. Choose the template you are using for the form in question.
For grabbing the page title, and I'm assuming the form is wrapped in a channel entries tag pair, create a hidden form field  my_subject or something, and assign it a value of {url_title}.
Then in your notification template put {my_subject} in as the value along with whatever you'd like in for the value of the Subject field.


How to scan a PDF for malware?

Question: Can anyone suggest an automated tool to scan a PDF file to determine whether it might contain malware or other "bad stuff"?  Or, alternatively, assigns a risk level to the PDF?
I would prefer a free tool.  It must be suitable for programmatic use, e.g., from the Unix command line, so that it is possible to scan PDFs automatically and take action based upon that.  A web-based solution might also be OK if it is scriptable.
Answer: Very easy.
Didier Stevens has provided two open-source, Python-based scripts to perform PDF malware analysis. There are a few others that I will also highlight.
The primary ones you want to run first are PDFiD (available another with Didier's other PDF Tools) and Pyew.
Here is an article on how to run pdfid.py and see the expected results; Here is another for pyew.
Finally, after identifying possible JS, Javascript, AA, OpenAction, and AcroForms -- you will want to dump those objects, filter the Javascript, and produce a raw output. This is possible with pdf-parser.py.
Additionally, Brandon Dixon maintains some extremely elite blog posts on his research with PDF malware, including a post about scoring PDFs based on malicious filters just like you describe.
I, personally, run all of these tools!
Comment: +1 good reply, Didier Stevens is the main focus when looking at PDF based malware. He also has tools such as 'make-pdf-javascript.py' which enable you to create proof of concept malicious PDFs to understand their structure more fully and why they are an issue.
Comment: Here is a newer tool with newer techniques from early 2016 -- http://honeynet.org/node/1304
Comment: Updated techniques -- https://itsjack.cc/blog/2017/08/analysingdetecting-malicious-pdfs-primer/
Comment: @atdre Using `pdf-parser.py`, how to find out if `ObjStm`s are malicious?
Comment: there are a few starting points here — https://zeltser.com/analyzing-malicious-documents/
Comment: thanks for all the resources!  I don't mean to sound ungrateful, but: to be honest, what I was ideally hoping for was a single script that I could run that outputs a binary answer ("this looks like malware" or "this looks safe").  In contrast, the resources you mention look like they're intended for for a professional analyst who wants to poke through the contents of a PDF file and form an opinion based upon their human judgement.  Do you know of anyone who has packaged these up into a single script that produces a yes/no answer (or a numeric risk score)?
Comment: @ D.W. Yeah that last URL I mentioned does what you want, but it does happen to be a Python script. It's really easy to install Python -- don't let it scare you!
Comment: More updates --
 https://securityoversimplicity.wordpress.com/2017/09/28/not-all-she-wrote-part-1-rigged-pdfs/
Comment: can pdftk be used to dissasemble/reassemble it discarding any bad embedded stuff (at lest 99%)
Comment: maybe, but pdftk could be vulnerable, or linked library or any other system-wide security failure, to a memory corruption attack kicked off by said-same embedded stuff. an easy example of this can be found in CVE-2019-7113 via a specially-crafted pdf. unless you are debugging your own pdf file-loading code while at the same time reversing any-given pdf, you may never know depending on the evasion techniques employed during and after code execution. A few things might pick up on this activity, such as osquery (or any EDR) security/incident packs/configs; others defend against, e.g., GRSecurity.
Answer: Just came by this very recent blog post by Lenny Zeltser which is pretty much right on the money
6 Free Tools for analyzing Malicious PDF Files
http://blog.zeltser.com/post/5360563894/tools-for-malicious-pdf-analysis
The tools he mentions are:

PDF Tools suite by Didier Stevens
PDF Stream Dumper
Jsunpack-n
Peepdf
Origami
MalObjClass

There are details about each one and links to other pdf analysis documents at the blog post.
Answer: For the past few months I have been doing research on PDF analysis and how it could be better improved. While doing the research I found myself writing tools and scripts to help me get the job done and decided it was time to put something more useful together. PDF X-RAY is a static analysis tool that allows you to analyze PDF files through a web interface or API. The tool uses multiple open source tools and custom code to take a PDF and turn it into a sharable format. The goal with this tool is to centralize PDF analysis and begin sharing comments on files that are seen.
PDF X-RAY differs from all other tools because it doesn't focus on the single file. Instead it compares the file you upload against thousands of malicious PDF files in our repository. These checks look for similar data structures within the PDF you upload and ones that have been reviewed by analysts. Using this feature we can begin to see shared coded samples among malicious files or trends due to malicious author coding styles. The tool is still in beta, but I wanted to release it to the public to see what users thought. In my opinion the API is the most useful as you can begin to integrate rich PDF analysis into other tools and services with little or no cost.
Current features include:

Summary report
Interactive report (includes all the information I have)
Related through characteristics
Account access and features
Full API (submit, report, full object, etc.)
Searching (not all implemented, but all hashing aspects work)
Sandbox dump of JS code
Flagging of streams (malicious or not malicious) for logged in users (anonymous users can see how many people marked something as malicious)
Reports (last 50 ran among others (some not yet released) )
Social network hooks (causes some slowness, so I may replace this)
Basic help documentation
Image preview generation

Sample Report from PDFXRAY.com
Comment: Looks like this domain is down.
Answer: I am actually in the process of moving my tool (see Scoring PDFs Based on Malicious Filter - 9b+) to a hosted environment where you can upload samples through an API or web portal. In its current state it will scan the PDF, pull in as much data as possible and compare it against hundreds of other malicious files. Please send me an email and I will be sure to let you know personally when it is available for use.
In the mean time, you can use the filter I have created which detects a little more than 50% of my malware now. It needs to be tweaked a little, but I would be willing to take a look at your samples personally and give you my best guess. Like I said, email me and we can exchange information.
Comment: It should be pointed out that what you are asking for is very rare and a problem that not many people have solved. The problem is hard to approach given the flexibility in the PDF specification. The reality is that there is no scanner that I currently know of including mine that will dive recursively into nested objects where malicious content could live.

With that said, your best bet is to get up to speed just a little bit on what to look for in a PDF. Didier has good resources for that as well good posts. Read my blog and you will gain an idea of how I am approaching this problem.
Answer: Have you tried just utilising VirusTotal as an indicator of potential malicious content? I know this is my first stop for most file verifications. You could script up a curl request to their MD5 search engine perhaps?
Comment: I believe it does both? You should probably use SHA256 for future-proofing. Cheers Dre!
Comment: I thought VirtusTotal used SHA256?

How to scan a PDF for malware?


How can I implement an algorithm for multicore in Java?

Question: Modern computers have more and more cores. We want to change our current linear algorithm to use these cores.
A splitting of any algorithm to use different threads only makes sense if there is a free processor.
Are there any good libraries that can help to parallelize some steps if there are free processors?
I will give some examples.

If there is only one processor it makes no sense to create multiple threads. It will reduce the speed.
If there run 2 processes (requests on a server) on a core duo it make also no sense to start threads.
If there only one process on a core duo it make sense.

The abstract algorithm has 4 steps A, B, C and D. Steps A, B and C can execute parallel. Step D needs the results from A, B and C.
Edit: I means an mathematic algorithm. No IO, No events, etc
Comment: Even after adding the edit, there's still lots of reasons why your thread could be suspended. So I still think your examples are not very good.
Answer: This isn't necessarily true.
Depending on the algorithm, it often makes sense to split it into multiple threads even if there is only a single core available.  If there is any waiting on sockets, IO, etc, you can get benefits from this.  If there are 2 processes, the "other" process may not be using 100% of the other core, so threading can help here.  Trust your OS in this case to handle it correctly.
You can always check the processor count with Runtime.availableProcessors() to determine how to split it into separate threads.  Alternatively, you can use a threadpool, which should scale correctly with more processors.
In general, though, I would design your algorithm to use more than one processor if the algorithm makes sense to parallelize.  Most systems will have more cores/processors available, and you can always tweak your implementation later if you find it needs it.  If the process is long running, the overhead of generating the thread will be worth it - if it's already fast, it may be more worthwhile looking at other places to optimize.
Answer: Look at the various concurrent classes in Java 5 and onwards.  You most likely want a ThreadPoolExecutor - http://java.sun.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html.
The appropriate value of the ThreadPool will most likely vary from system to system depending on work load and hardware architechture.  Make it user adjustable.
Answer: For some ideas have a look at JSR166 and JSR166y (something like fork-join system with work stealing (166) and parallel array (166y) ).
Some nice reading and overview of the future directions for Java. Looks not that bad (strong support for high level concurrent and parallel programming).
Answer: I often have a fixed thread pool which is dynamically the same number of thread as the number of processors (see Runtime)
I add tasks to this thread pool so it uses all the processors available.
I don't believe you should try re-inventing the process scheduler in the operating system.  It does a good job so let it do what it does well.
Answer: Having more threads/processes than cores is not necessarily a bad thing. If your code is strictly mathematical with little I/O and no side effects, then yes, having a 1:1 correspondence between cores and threads is optimal. But this is not usually the case. I/O takes eons compared to clock cycles. Why stall the core completely while waiting on I/O when the OS can swap in another thread to keep chugging along?
The problem is there aren't a lot of languages/compilers that will make the concurrency decision for you. You need to design your program to take advantage of concurrency. And you probably need to design your program for multiple target environment, usually not under your control. So usually, best practice is to make threads for things whatever it makes sense to parallelize and let the thread scheduler handle it. The thread scheduler should be tuned for use on the specific hardware in question far better than you can tune your program for "whatever hardware comes along".
Answer:
The abstract algorithm has 4 steps A,
  B, C and D. Steps A, B and C can
  execute parallel. Step D needs the
  results from A, B and C.

This is a one-liner using the Ateji PX notation, an extension of the Java language:
<code>[ A(); || B(); || C(); ]; D();
</code>
Your responsability as a programmer is to express where there is a potential for parallel execution, that's the role of the parallel bars "||" in the code. The scheduler now is able to make the best use of available hardware, namely run A, B and C on three different cores whenever available.
This is a very high-level view, more parallelism may possibly be exhibited inside A, B or C.
Answer: I think you need a ConcurrentContext from Javolution. See at http://javolution.org/target/site/apidocs/javolution/context/ConcurrentContext.html


Does instruction which control unit fetch contain both what to do and where to do (in which unit of processor)?

Question: What instruction really means? I am facing problem in understanding it. If the instruction is to copy this and create a new file and place there so it seems it d doesn't need processing so what will control unit do?
Answer: In computer architecture (the current tag, but I wonder if it is really adapted), an instruction is whatever the computer architect decide to be.  It is the most basic bit string having a independent meaning.  Some instructions may be quite simple (add two registers and put the result in the first one), some may be strange (provide the most significant bits of a constant value used in the next instruction) and the boundary between being one instruction or several may be not that clear (you could consider the previous example and the instruction which follow it as a single instruction).
I don't know any processor which provides instructions like the one you are describing.  Those seems to me to be at the abstraction level of an operating system, not of a processor architecture.  It could be that mainframes provide such instruction (in the channel control part), but even there my guess is that it would need to be the combination of several more basic instructions.  That guess holds also for operating system.


usage of infinitive after feel

Question: What is grammatically wrong with the sentence,  "I feel to eat."?  After the verb feel, can the infinitive of another verb be used?
Comment: I would recommend to use "feel like to do" instead of "feel to do".
Answer: Infinitives are not usually used after the verb to feel.  To express desire, the usual construction is I feel like + gerund, which is to say I feel like eating.
If, however, you prefer to use an infinitive, then change the finite verb: e.g. I want to eat, I wish to eat, I hope to eat are all correct, but never *I feel to eat.

usage of infinitive after feel


Pokemon go crashes down

Question: I have a Vivo y11 smartphone with 512mb ram. I know it is not sufficient to run Pokemon go, but still I want it. It crashes down every time.
Comment: getting a better phone would probably help a lot more than trying to use an unsupported device.
Answer: This game is new and maybe contains alot of bugs and errors.
Make sure you disable, Mobile Data when you are not outside and you have access to WIFI. Two connection at same times will freeze/crash the game.
An other thing is to deactive the Camera when you catch or battle something because this sometimes causes crashes if you do something wrong.
People say it also depends on the country because of the Pokemon GO Servers
Make sure you are not far away from a pokemon stop, pokemon arena or pokemon while using them or contacting them, because if you move far away you can't catch it anymore and this causes crashes if something didn't went good.
If it crashes you should try to click the button again until it works, and if you have problems at the starting you have to reinstall it.

Pokemon go crashes down


Differentiability of Overlapping Piecewise Functions

Question: Suppose $f(x)$ is differentiable on $U=(-\infty, 0]$ and $g(x)$ is not differentiable at $V=[0,\infty)$ but is differentiable on $(0,\infty)$.  Is the following piecewise function $h(x)$ differentiable?
$$
h(x)=
\begin{cases}
f(x) \text{ for } x\in U\\
g(x) \text{ for } x\in V\\
\end{cases}
$$ Note $U\cap V=\{0\}$ and $f$ is differentiable at $0$ but $g$ is not.  Disclaimer, I'm not sure why you would want to consider a piecewise function with "overlapping pieces" but I was asked to.
Comment: What have you tried so far? What do you think the answer is? Does your intuition tell you that $h$ is differentiable or not? How would you go about proving what your intuition tells you?
Answer: Hint: For $t > 0$,
$$
\frac{h(0+t) - h(0)}{t} = \frac{g(0+t) - g(0)}{t}
$$
Also, it is common to construct a "global" function by piecing together smaller (often more "local") functions. So, this construction is not solely for the point of pedagogy.
Answer: The condition on $g$ tells you that $g$ is not differentiable at the point $0$.
Then examine derivative from the right
$$
\lim_{x \rightarrow 0^+}\frac{g(x)-g(0)}{x}
$$
Which you already know does not exist.


Black Screen Boot & Freezing Boot

Question: So I'm working on a friend's computer to install Linux Mint 18.2 onto it since his Windows broke after the Creator Update. He wasn't able to install it himself for some reason, however when I first tried the Live USB on the system, it booted right into the Live USB and I was able to complete an install to his SSD. After the install, we attempted to reboot into the installed partition, however it goes to the GRUB menu, and once we select the installation for Linux Mint it just goes to a black screen with nothing on it, we've waited over 10 minutes with no changes to the screen. We then tried the Live USB again, multiple times and gives us the same thing as booting into the partition, a blinking underscore in the corner for a second and then just a black screen, then the screen goes to sleep. Systems specs are an FX-8350 and a Radeon R9 280X, no onboard video
What have we tried?
We've tried changing the boot parameters to have nomodeset xforcevesa instead of "quiet splash", this works about 10% of the time to get it to boot into Mint from the installed partition. The other 80% it goes to the command line output for booting into everything and reaches Switching to clocksource: tsc (or something similar) and then just freezes and doesn't go anywhere. The other 10% it just hangs in the middle of boot sequence.  If we keep quiet splash and put in the nomodeset xforcevesa we receive an ERROR no UMS support in radeon module
We also tried just a nomodeset, this doesn't seem to have much affect, maybe 1 % or less of the time it loads into the OS.
We tried a live USB of Ubuntu 16.04 LTS, I have not been able to boot into it at all, even with the various parameter changes. We've tried using noacpi and nolacpi and acpi options in the Ubuntu Live USB to no avail, gives us I believe the ERROR No UMS Support in radeon module errors.
We've tried a live USB of Linux Mint 17.3 since we've discovered that AMD drivers for 18.2 aren't supported until AMD rewrites everything I guess? Didn't make sense to me, but that's what we read on the forums. Was unable to get 17.3 to boot at all, even with parameter changes.
Comment: Maybe it is related to your bios secure boot configuration?
Answer: Most likely the live cd is using some fall back drivers or something similar. Whatever the reason, below will probably fix you right up.
After installing Mint boot into recovery and install the proprietary driver from the driver manager. Source: https://community.linuxmint.com/hardware/view/21443

Black Screen Boot & Freezing Boot


How can Demons kill Devils?

Question: In Blood War, Demons kill Devils.
However, many Devils have the regeneration special ability.
Demons never use Good-aligned weapons and spells.
So... how do they kill those?
Comment: The question is generic. Only a few kinds of devil has regeneration, not all.
Are you interested in something specific?
Answer: Per RAW? They don't (usually)
Because the wording used across all of 3.5 is the same standard boilerplate for anything that isn't the align weapon spell or the holy weapon property, there is a shocking gulf between the kinds of things one would expect to work, and what actually does. The fact that creatures with an alignment subtype have their natural weapons treated as having that alignment "for the purpose of overcoming damage reduction" means they don't actually have that alignment - and that's the wording you will find on virtually every other method of attuning your weapon to hew through a creature's native defenses.
"For the purpose of" limits it far more than it arguably should, though that gets into a question of RAI. I would personally be extraordinarily surprised if every author who copypasted that rule actually understood how it related, as written, to regeneration, since aligned regeneration is considerably harder to contend with under these terms than any other kind of regeneration. Troll regeneration is a unique tactical question, a signature characteristic, and a mild inconvenience. Conversely, aligned regeneration requires (in this instance almost literally) a silver bullet.
What this leaves us, per RAW, is that a celestial with silver-coated talons can't do anything more to a cornugon than a mortal with a butterknife, not unless good-aligned damaging spells enter the picture, and as we already know, demons don't have ready access to those. Of the methods that are most viable to address regeneration, demons don't generally have 5th level spells on hand to cast graymantle, trollbane works as a poison and so doesn't work on devils, and of course the actual vulnerability in question - good-aligned weapons - is something of a non-starter.
Now, of course, the armies of the Abyss, not unlike the armies of Hell, have assets other than demons - it's quite feasible that a mortal spellcaster with access to graymantle is available to help put down a cornugon, at least from time to time. That being said, spell resistance makes that a horribly unreliable method.
The one exception
...but then you have the lilitu. A lilitu is capable of using holy weaponry without taking the penalties normally associated with it, and can use other good-aligned items (including scrolls of holy smite etc.) with total ease. Capable of using detect good at will and practiced specifically in the art of deceiving and undermining religious faith, a lilitu likely has access to such materials as needed and would find it hilarious to turn the tools of benevolent gods to the purposes of the Abyss.
Now, that being said, "special forces" isn't really a lilitu's purview, or her field of interest; lilitus do not like to engage in melee combat and probably don't care about the Blood War at all. As demons, and thus paragons of selfishness, they would have very little reason to get involved as cornugon-busters.
That being said, if you are cleaving to hard RAW exclusively, then lilitus paid or coerced into service as blasphemous mockeries of paladins are an absolutely valid way that demons can kill regenerating devils.
The impersonal touch
These elite devils also had the ability to regenerate in 2nd Edition, and demons had no unique capability to pierce it at that time either. This is relevant because 2E introduced the Blood War and talked about it at length. From Hellbound: The Blood War, we are specifically told:

For example, many fiends who fall in battle regenerate and rise to fight again - unless, of course, they're dispatched for good. Mortals can help make sure a dead fiend stays dead by dousing it with holy water or whacking it with a holy weapon.

So it seems that the favored solution, by and large, is just to beat the absolute stuffing out of anything that can regenerate to the point that it either elects to leave or can be dealt with using a handy mortal underling with a blessed silver dagger.
But stepping away from RAW...
...that same book also tells us that, since so many of their spell-like abilities are garbage in the Blood War, many fiends of all stripes work to develop different abilities, or seek to master spellcasting - some by trading away their capacity to use spell-like abilities. Such fiends could certainly pick up assets such as the graymantle spell which would at the very least give pause to a normally confident gelugon or cornugon.
There's also the simple fact that in the chaotic realms of the tanar'ri, an endless variety of horrifying types of demon exists within the roil of the Abyss. There's no reason why there wouldn't be one or more breeds ideally suited to breaking through such regeneration - perhaps counterparts to the ghoulish maurezhi and nabassu, which gain power by eating humanoids, there could exist some manner of scavenger fiend herded into Blood War battlefields to seek out unconscious baatezu whose wounds are reknitting and gnaw them to death.
Lastly, of course, we can simply look at it from the Doylist perspective and say that it's one of those omissions in what RAW contains based around the rules that would generally be needed for players and DMs - the relevant ability for demons to handle elite devils does exist, at least at some echelon; it was simply never written into their descriptions as it would not, by and large, be pertinent to the experience of using such monsters in average play. When it comes to planar ecology and interaction, this sort of omission is readily apparent in 3.5 - see for example what happens to undead on the Positive Energy Plane (they just get healthier and healthier forever, as they are never required to make the Fortitude save by RAW).
Answer: Regenerating creatures can be killed
The description of the Regeneration power includes:

A regenerating creature that has been rendered unconscious through
  non-lethal damage can be killed with a coup de grace (see p153 of the
  Players Handbook).  The attack cannot be of a type that automatically
  converts to nonlethal damage.
Attack forms that don't deal hit point damage (for example, most
  poisons and distintegration) ignore regeneration.  Regeneration also
  does not restore hit points lost through starvation, thirst or
  suffocation.

In short, a demon can most commonly kill a devil by reducing it to unconsciousness and administering a coup de grace.
EDIT:  As @Mouza noted in comments to this answer, the coup de grace damage must be done with a damage source that is not automatically converted into non lethal damage.  For the subset of devils that possess the regeneration ability, this varies.  For the chain devil, silvered weapons will suffice, there is no need for the weapon to be good aligned.  For others, such as the Horned Devil, the weapon must be either silver and good-aligned or a spell with the "good" descriptor (hence the OP's question).  However, while devils are immune to poison, they are not immune to starvation, thirst or suffocation.  Starvation and thirst are too time-consuming for most battles (but would likely be preferred by sadistic demons as a means of executing prisoners if feasible), but suffocation is an option which could be implemented on the battlefield.  The devil would presumably need to be either restrained once unconscious or continually damaged while suffocation was ongoing to prevent it breaking free.
If the demon has other powers that do non-hit point damage then they can use those also (although devils are immune to poison unless noted otherwise).  The battle between a demon and a devil may take a long time given the effects of both regeneration and damage reduction, but neither side has anything better to do.
Comment: Wait...it is not that simple. Keep in mind that the demon MUST be capable of dealing lethal damage to a devil for killing it with a coup de grace since every damage is converted automatically in nonlethal damage and you must deliver a coup de grace with something that deal LETHAL damage to the devil.
Comment: @Mouza good catch, have updated answer to (hopefully) address the point raised.
Answer: Not many devils have regeneration which requires good-aligned weapons.
The SRD lists eleven types of devils. Of these, only four have regeneration; of those, kytons (chain devils) have regeneration which can be overcome by silvered weapons (or good). A demon army fighting devils will almost certainly be carrying plenty of silver in order to overcome the DR on all low-level devils, so kytons are a non-issue.
The other three are gelugons (ice devils), cornugons (horned devils), and pit fiends (run away).
Gelugons (CR 13) are typically commanders and strategists, so they will be rare creatures among vast masses of lower-powered troops. A demon army might have a few specialists who are capable of dealing with gelugons - maybe some unlucky demon who has to suck up the penalty for using a captured good-aligned weapon, maybe non-demon creatures who have been compelled or paid to help out - but they don't need a lot of gelugon-killers.
Pit fiends (CR 20) are also commanders, and very rare. For any force to destroy a pit fiend would be an exceptional event.
Cornugons (CR 16) function variously as force commanders or as shock troops. However, their high CR implies that they're pretty rare. An opponent strong enough to be taking on an entire squad of CR-16 monsters at all should have some options for doing lethal damage here.
Answer:
Outsiders breathe, but do not need to eat or sleep (although they can do so if they wish).
  - Monster Manual p. 313 (Outsider Type)
Attack forms that don't deal hit point damage (for example, most poisons) ignore regeneration. Regeneration also does not restore hit points lost from starvation, thirst, or suffocation.
  - Monster Manual p. 314 (Regeneration)

So starting here, we have a clear vulnerability that most fiends possess, even the ones with regeneration: Suffocation. All we need is a way to exploit it.
A wand of create water (the spell being an orison for clerics, such as many middling fiends) is valued at 375 gold pieces, a steal in relation to any spoils that might be won. All that's demanded once the demons have scored their victory in battle is a low point in the earth, or some manner of hole, for holding the water. Even a portable hole could work; the suffocation rules apply as per usual, and water just helps it along.
Some would say that using magic items like this is not the domain of demons. I say demons often have Intelligence scores above 8.
Comment: I feel like there's a valuable answer here -- "deal enough damage to the target to knock it unconscious, then drown it, either in an existing pool or after making one with a wand."  I think this answer would be improved if you added more description about what exactly the problem is and how this is the best solution.  +1 anyway.
Answer: I find I have to disagree with one of the question's premises, namely -

Demons never use Good-aligned weapons and spells.

Why not? While demons will indeed suffer penalties for toting around good-aligned weapons, I can imagine a weapon with the Holy Enchantment on it would be quite valuable to a demon fighting against Devils, or in fact, even other demons. The only penalty for wielding such a weapon is gaining a permanent negative level...this seems to me like a small price to pay for a method of permanently overcoming such common adversaries.
Similarly, what would prevent a Demon or Devil from carrying around and UMDing scrolls of Align Weapon? Or even flasks of Holy Water? (perhaps stored in lead-lined boxes to prevent any possible cross-contamination)

How can Demons kill Devils?


Staking deactivating

Question:
I have deactivated my staking of sol 2 days ago but it is still showing deactivating. I'm new to Phantom so I Don't know how much time will will take to compete the Process. If anyone knows then Please let me know. Thank YOU so much.
Answer: When you deactivate stake, it takes until the start of the next epoch for it to be deactivated.
Epochs usually last a little over 2 days. The next epoch will finalize in less than 4 hours, and that's when your stake will be available for withdrawal.

Staking deactivating