What is the difference between vPs and v*Ps?

Question: Why do I sometimes come across a label like v* instead of v in the literature? As I understood, it is the same thing.
Comment: I've only seen √P for 'root verb phrase'
Answer: They are not the same. 1. v* (with this label) corresponds to a verb projection with a full argument structure or what is called a Core Functional Category (CFC) with transitivity. This v*P is the small or light vP that can enter into a checking relation of Case/Agreement. Its head, along with C and T, constitutes the set of CFC. Also this head is always transitive in nature, it selects another V, it has phi-features for object agreement and case, and finally it has an optional EPP for object shift constructions. 2. The other v (the normal light or small v with no * label), however, is the one that Legate (2003) reacted to Chomsky (2000) for, saying that also passives, unaccusatives, TPs, other authors even suggested DPs, are phases on the basis of some phasehood tests she clearly shows in her article (based on wh-movement & Binding). To this point, Chomsky (2001) in another article has drawn a line between strong and weak phases, these weaks phases he considers passive/unaccusative vP, TPs, etc. They are not labelled v* because they don't have a fully argument structure. So indeed there's a difference. You could say that the light or small v (v*) is more functional in nature, and the normal light v is thematic or substantive in nature. This is briefly the difference between them as far as I know.


Is there anyone who has 0 questions but lots of answers? Why?

Question: Why do some users have many many answers but no questions of their own? How does that benefit them? Can it prevent suspensions?
Comment: Some people have questions, others have answers. Why should everyone ask questions?
Comment: Well, I can safely say that I'm most unlikely to get a question ban on ELL.
Answer: Nope. Some people just... don't like writing questions or don't have any to ask.
I write lots of meta questions (and answers) but on my highest reputation site, Movies & TV, I've asked only one compared to 176 answers... and on my second highest reputation site, English Language Learners, I have no questions and 321 answers.
I'm not sure how that's "gaming the system", though... some people are naturally sources of knowledge and others are searchers for knowledge. I'm a native English speaker, so there's not much to ask about on ELL (I have asked a few questions on English Language & Usage, though) but I'm able to answer many questions because of my innate knowledge of the language.
The benefit is the joy of helping others. I love to help people improve their knowledge in the subjects I'm an "expert" in. Sharing my experience with them is a reward... as is the reputation earned for good answers.
We actually incentivize people to write answers by offering more reputation for each upvote received on an answer.
Are there any advantages to not asking questions - nope. But there are no disadvantages, either... well, you can't get some badges if you never ask questions but that's a minor thing.
Suspensions are completely unrelated to writing questions or answers. High reputation users are suspended just like low reputation ones and whether that reputation comes from questions or answers is irrelevant.
Questions feed the site, drive it forward. With no questions, no answers could be written. Answers are what draw users to the site, though. Users who write good answers are valuable but not so valuable as to save them from being suspended.
Comment: So there is no strategic value?
Comment: It's sort of difficult to prove a negative... can you be more specific about what *sort* of value you're thinking about? When I fail to write questions it's not because I'm doing it strategically... I just... don't have any questions to ask. I tend to accept things the way they are.
Comment: You have plenty of good questions. I would like someone with no question to say why?
Comment: I don't think that anyone on the network has zero questions across the entire network. I have questions here... and I say that in my second paragraph... but look at my accounts on the two sites I mention.
Answer: Depends on why you're here. I have relatively few questions because I tend to use the sites as a way to sharpen my skills and find fun problems to solve over using it primarily as a support mechanism.
So... on point

Why do some users have many many answers but no questions of there own?

Cause that's how they roll, and answering questions is their main interest here. It is a little odd, I suppose, since I sometimes use self answered questions to share knowledge, but say I was a software dev who hung out mainly on the tag of something I wrote, I might not really be inclined to ask questions.

How does that benefit them?

Its fun? I've always felt there's a few classes of legitimate users. We might be here for different things. There's a certain thrill to picking apart and putting together someone elses problem, and presumably some people live for that.

Can it prevent suspensions?

Depends on the reason. You're certainly not going to hit a qban or poor quality question suspension if you post no questions. However, manual suspensions are mostly related to things you've done.
Hypothetically, I could hit enough reputation on one site to get the association bonus, get commenting abilities, and then go cuss out someone in comments to get suspended. Without even posting once!
Comment: I would never do that, Every opinion is valuable to me even the bad ones. I want to earn mine as fast as I can fairly without getting blocked or suspended.
Comment: In a sense, there's no magic way not to get suspended, other than not doing stuff that would get you suspended.  be excellent to each other, and be awesome, and all is good ;p
Comment: It is really hard to ask a good question here.
Comment: Yes, but downvotes in a meta.SE question mean a different thing to downvotes on a SE question
Comment: Yup. And sometimes on meta, the downvotes actually are a sign you're doing something *right* ;p/
Answer: You can delete a bad answer anytime not a question. You have to wait 40 minutes to ask another question anywhere on SE and 3 minutes between answering. That is the advantages I found so far. Feel free to add here.
Precautionary: If you answer too many low-quality answers it will get you suspended faster.
Comment: But questions *can* be deleted under certain conditions. And answers cannot always be deleted—being accepted prevents an answer from being deleted by anyone other than a mod. This is all mentioned in this [FAQ](https://meta.stackexchange.com/a/5222/323179).
Answer: In answer to the fact based question you asked, Stack Exchange supports a query interface where you could, if you wanted, build and run a query to find users with a high answers:questions ratio.
Take a look at https://data.stackexchange.com/stackoverflow/query/new
You also asked a more subjective "why?" - there's no good provable fact based answer to this.
I suspect most users who seldom ask questions behave that way because they already know enough about a subject that they have no current want or need to know anything else. When that changes, maybe they will ask a question, maybe the will google for an answer.
I answer a lot of SQL questions, yet I don't think I've ever asked one - I know a lot about SQL queries, I've written tens of thousands of them in my life. I even answer sql questions that relate to databases I've never used, or even heard of. Any minor questions I might have during writing an answer, like "how do I escape a column name in SQLite", I hit google for and often I'm led back to stack exchange
To ask my query again on SE without putting some effort into researching its prior existence would be slow, require more typing than hitting google, and likely end up being close voted as a duplicate (because most of what I don't know has already been asked)
There's probably no deep and meaningful conspiracy theory based gaming of the system for high answer:question ratio users; they simply know everything they need/want to


Slow play backfire

Question: In a loose $1/$3 NL holdem I recently played, I had KsJs in small blind with about $430 stack size. I raised to $16, there were 3 callers: the big blind, MP and button, flop 9TQ rainbow, I had the nut straight. I wanted to slow play, so I checked, hoping someone bet, I'd just bet to hide strength. Unfortunately, they all checked, and turn was a K, very bad card for me. So I bet $80, the small blind, who had a short stack of about $200, went all-in right away, MP folded, and the button who had me covered, after a little pause, announced all-in too. I thought the big blind likely had AJ, but the button likely had only J or 8J, so I would lose to the big blind but win from the button, I called. Turned out they both had AJ. Question: what is the best play for this scenario?
Answer: Just becuase your slowplay didn't work out well this time, it doesn't say anything about whether it was a good play or not. I'm more willing to value-bet on the flop though, since you have the nuts and your opponents would have probably some piece of the flop. Depending on the skill level of the table, you may get calls from all sorts of straight draws and perhaps even some Qx.
In general, it's a good principle to bet strong when you have your strongest hands. This will not only increase the profitability of those monster hands but also make your bluffs much more respectable.
Comment: I am going to second that notion of value betting on the flop here. Generally after a player raises pre-flop, then checks I am much more worried they hit the flop then if they bet. On this hand you miss a lot of value by checking.

Slow play backfire


Routing with private addresses

Question: Let's say that we have a private network, with private addresses and a NAT enabled router at the end. If the router is misconfigured and routes traffic to the global internet, keeping as source address the private one, at which step of the path will a packet be filtered if it is sent by a local PC to a server that has a global IP? Could that packet reach a server? This question is purely theoretical obviously.
Answer: There's no precise answer.  Most ISPs filter out private source addresses, but not all.  If they don't, the packet could (in theory) reach the destination.  However, the return packet would be stopped at the first router that has filtering or the first router with no default route.
Answer: IP has no concept of private or public addresses. For IPv4, we have RFC 1918 that set aside three address ranges for Private addressing, but all that really means is that the ISPs have agreed to not route packets with those addresses on the public Internet.
IANA maintains the IANA IPv4 Special-Purpose Address Registry, which has a table of the special address ranges, including Private address ranges. The table explains if the special address range is recognized by IPv4, itself:

Reserved-by-Protocol - A boolean value indicating whether the
special-purpose address block is reserved by IP, itself.  This value
is "TRUE" if the RFC that created the special-purpose address block
requires all compliant IP implementations to behave in a special way
when processing packets either to or from addresses contained by the
address block.

Address ranges that are True for Reserved-by-Protocol must be recognized and treated specially by an IPv4 implementation, but those that are False need special handling for special use by an end host, otherwise they are treated as normal IPv4 addresses, and IPv4 does not know about them.
Notice in the table that all three Private address ranges are False for Reserved-by Protocol.
Answer: Firstly your question is not precise to answer ..
Basically when pc wants to communicate server hosted in internet it will check for routing or route table to reach the destination . To forward packet from souce to destination fallowing tables are verified

ARP table
mac -address table
routing table
NAT table

For example
When traffic is initiated from source pc witth private adress . It should reach  edge router . Edge router should connected with ISP and ISP provided public ips should be configured as interface ip for egress interface and  default route as to configure in router pointing ISP gateway and NAT policy should be configured in router ..
Packet flow
Traffic is initiated from pc with souce as private ip address allocated to pc . packet is forwarded to router . Router will verify destination address of packet and check for route in routing table and forwards packets to ISP gateway before forwarding it will  do NAT translation from private address to public ip beacuse private ip address are not routeble  in internet
Traffic is filtered on basic of access-list, route entries configured on edge routers At some point in traffic flow from source to destination there are specific routes configure at ISP level at this point packet will get dropped this might be happen for  forward direction of packet  or for reverse traffic of same session

Routing with private addresses


Is writing about your childhood in creative writing/fiction class necessary?

Question: I have the same teacher for both a Journaling autobiographical class and a fictional writing class. While I expected to have to write about my personal life with one, she seems determined to have me gut my childhood with the fiction class as being necessary for fodder for eventual stories. I have no intention of ever writing in that vein, and I am finding this to be invasive and offensive at this point. Is it necessary to delve into my dysfunctional childhood in order to write good fiction?
Answer: All writing is, in some way, rooted in our experiences

The story you want to write isn't always the story you need to write. Before finishing my novel, I was under the impression that my characters could exist without unsolicited influence. In other words, I believed that my story would be entirely free from my unwanted personal experiences and emotional obstacles. I quickly learned that I was wrong—it's almost always impossible to prevent trauma from trickling into your writing.
-- Danielle M. Wong (Writer's Digest)

Whether you do it actively (as your teacher is requesting) or subconsciously, your life experiences will have an impact on what you write. It is inevitable and impossible to avoid. Even if you have the greatest imagination in the world, it is shaped or flavoured by the things you have experienced.
I imagine what your teacher is trying to get you to do is accept this and use it to write better fiction. Rather than holding yourself back trying to avoid it. I once thought as you do, writing about my personal life was invasive and unpleasant. I didn't want to do it and avoided it whenever I could.
In my final year of high-school we were given a writing prompt, "Write a story centered on your favourite childhood toy." I didn't realise at the time how personal this prompt was and went ahead and wrote from it. What followed the piece of writing of which I am the most proud. It is emotive, unique and compelling. I submitted in for multiple assessments and received full marks each time, including one assessment where creative pieces are rarely well reviewed.
What I learned from writing that piece has made me a better writer. It highlighted things I was good at, and where I needed more practice. It added depth to my characters and allowed me to connect with my writing on a level I hadn't achieved before. So while it is easy to say "of course you don't need to" there is no one way to be a great author; the more I think about it, yes, writing about your own experiences is a valuable step on the way to being a better writer.
But it's too personal and I don't want to share it
That's fine! I believe that this kind of writing isn't for sharing, it is for you and making you a better writer. Do what you need to get through these classes, write with the bare minimum of details, or even make something up! They won't know the truth.
But when you feel ready, write something like this for yourself, you might just learn something about yourself along the way.
Comment: As a writer who barely remembers their childhood at all, even I think you are probably right.
Answer: All the other answers hit very important points:

our life experiences deeply affect us and how we write
writing about life events, personal objects and people in our lives can bring a vitality and emotion to the writing that is more difficult to express about things and people that never touched us
while an autobiographic class may require you to bring forth real life events, it can't force one to write and make public something you do not wish to share
writing from real life experience supposedly simplifies the writing process (where it comes to motivations, etc), but some people act in ways that they themselves don't fully understand why until they stop and carefully reflect about it

I understand that one's life experiences affect how one writes, but one has so many life experiences, that one can actively pick and choose. Moreover, one can get hold of the emotion and use it for a different scenario.
Let's say that the teacher asks you to write about the loss of someone dear, but you do not wish to share true events. You can create a character that is a differente gender and, if appropriate, a differente age. You could even write about a kitten who's lost his mother! That way you can clearly distantiate yourself from the real people and use only the emotion that you have experienced.
However, if you do not wish to revisit the emotion itself, you can either create a sense of 'emotionless' on the characters (either because they can't feel emotion - ie, a sociopath(1) - or because they're in shock and can't process the events, therefore feeling almost nothing until later on, or even because they're animals and don't feel emotions), or you can detach yourself from the character. Have the narrator be someone else who observes the actions of the person who lost the dear one.
Notes:
(1) A sociopath doesn't have to be someone who revels in other people's pain and suffering; it is simply someone who feels no empathy. This means they can feel the sense of loss of a parent, and even feel sadness about it, just not in the same way as others.

Is it necessary to delve into my dysfunctional childhood in order to write good fiction?

Once I was told I should include twin siblings in my novel for the simple reason that I'm a twin and, therefore, it is the sibling relationship I'm most attuned with and it would add a touch of real emotion. The person hadn't even read a word of my draft! I felt like pointing out that twins can develop a relationship of deep love, hate or even indifference, just like most other siblings. I've met other twins and I know there's a wide variety of bondings. But the thing is: that particular life experience had nothing to do with my story. Feelings of losing a parent? Reacting badly to criticism? Feeling rejected? Yes. Sooner or later, we all get to experience those, after all.
In order to write good fiction, one needs to manage to put into words emotions that ring true to the reader. However, a good writer may be able to write a poignant love story without ever having been in love. If one understands the emotion (ie, researches and reads about real people expressing what love is for them until one understands the immense variations and faces that love can take on), that is perfectly feasible.
What you need to delve into is how you feel emotions, and then compare to how others feel emotions. Listen when people share their feelings - whether of sadness or happiness - and don't jump to say 'oh, no, I've never felt like that about this event', but instead try to imagine yourself in their shoes going through those emotions. Understand how they feel, even if it may be impossible for you to really know how they feel.

she seems determined to have me gut my childhood with the fiction class as being necessary for fodder for eventual stories.

I'm sorry but I must ask how this 'determination' expresses itself. Does the teacher ask for specific details? Does she actually say 'write about those emotionally gut-wrenching events in order to get a more poignat and vivid tale'? Or does she say to 'funnel' those emotions into your writing?
If it is the former, then have a private word with her and calmly express your desire of exploring more joyful experiences and/or other life stages. If she by any chance mentions how important it is not to disconnect from the bitter past or other such things, inform her your therapist says you have digested the 'bad' enough and it's now time to embrace a brighter future. Which is what you intend to do in your writing. Do feel free to invent said therapist.
If it is the latter, then perhaps the teacher doesn't really want you to re-hash real life events into your writing and simply wants you to use the strength of your emotions. If in the past you felt angry over things that happened to you, write about a grumpy old man who is angry at the whole world. Write about a person who is angry because they have just lost a promotion since the boss preferred to promote his nephew. Use the strength of the real emotion in a completely different event.
However, if you feel there is a great emphasis in dark situations, either talk to your colleagues and see if the group can ask the teacher for some more uplifting exercises, or try to twist the darkness into light. If the exercise is to write about death, then let your characters belong to a religion where death is joyful - since one stops suffering - and then focus all your being on that silver lining: yes, I've lost my dear friend, but I am deeply happy for them and I look forward to meeting them when my hour comes! You know, just like you'd be happy for a friend that moved to Australia to get married and start on their dream job even if that means you can never meet them again.
Good luck with your course.
Answer: Chophousepop use this moment as an opportunity.
I would say that for a writer to mirror a character in a story after their own life would be a challenge. So much so, that doing so would bog down the story making character development feeling forced as opposed to being organic. Don't take your teacher's request this too personal but rather build a fictional character that you may identify with instead.
You identify with this character because there may be something you and the character have in common. Best commonalities to explore would be values as opposed life events.
Randy Ingermanson has a great expression that your character can speak in their character voice to establish values.
Your character says: "Nothing is more important to me than…"
You feel in the blank.
Flesh your character based on traits that don't reflect on your areas of your life that you feel are private.
Answer: It seems like a decent way to be introduced to creative writing.  You already know the plot and the main character's personality and motivations.  To me, it seems like your teacher is trying to ease your burden in regards to the big decisions in writing, so you can focus on improving the little stuff; sentence structure, vocabulary, things like that.
Imagine writing a brand new story, as opposed to your childhood.  Not only do you have to make each sentence sound good, but you also have to decide everything else; who the characters are, what they want, why, and how they'll try to get it.
If your childhood was traumatic, you could ask your teacher in private if you could write about something else.  Or you could simply not tell those parts, surely you don't have to write absolutely everything that ever happened to you.
Comment: The specificity of the assignment was "make us crg
Comment: Do you mean "make us cry"? So your teacher already knows that your childhood was traumatic to some degree?
Comment: I think my final point still works.  Just because your teacher wants an emotional story doesn't mean you have to tell the most depressing story you can.
Answer: This is an area in which I believe an entire industry has got it wrong. The creative aspect of creative writing is ignored because you cannot teach it. Fiction and non-fiction are totally different disciplines requiring different skill-sets. Non-fiction involves clearly and succinctly relaying facts. Fiction requires the writer to feed the reader's imagination.
Your teacher is wrong. Personally, I'd prove the point by writing about genuine childhood experiences in one class, and detailing how you were raised by wolves in the other.
Comment: I've been in a couple of classes that did make a serious attempt at teaching creativity, or at least made tapping into it easier. To say the entire industry's got it wrong...
Comment: *"Your teacher is wrong."* Can you support this with evidence or experience? At the moment you are just stating opinion. Answers are more useful if you can back them up. See [Good Subjective, Bad Subjective](https://stackoverflow.blog/2010/09/29/good-subjective-bad-subjective/) for more information.
Comment: Allow me this moment to rephrase. I have spoken to a few other professors, who have also agreed that this particular assignment was handled badly or "the teacher was wrong" there was no safety net for the students once she asked them to cannibalize their trauma. Some of the themes, death of a baby sibling during a winter when they could not afford utilities, CWS breaking up families, and sexual abuse. Most of the class is 18. Didn't realize what it would mean to share those things with an open forum. There was no caveat, nor back door for this assignment most did it without question.


DNS server IP address of redudant domain controller

Question: I have two redudant Windows Server 2012R2 domain controller. The DNS is active directory integrated. Which order of dns ip address should the two domain controller have and why? Are there experience of Microsoft? Thank you in advance!
Answer: They should be looking at one another first.
127.0.0.1 second.
No matter how many domain controllers you have, you should always configure your DCs to look at another DC in the same site first for DNS, then a DNS server in another site if applicable, and 127.0.0.1 should always be listed as the last DNS server.
Source: Microsoft Best Practices Analyzer.
Even though the "island" problem that would occur when a domain controller looked only at itself for DNS has been largely mitigated, there are still rare situations where it can occur.
Secondly, a domain controller needs to look to another domain controller for DNS first, because it will cause delays in boot up time and take services longer to start up on that domain controller if the DC starts up and doesn't have an already-online DNS server to make queries to.
Comment: Yes. http://technet.microsoft.com/en-us/library/ff807362(v=WS.10).aspx

"The loopback IP address should be configured as one of the DNS servers on each active network adapter, **but not as the first DNS server.** If the loopback IP address is the first entry in the list of DNS servers, Active Directory might be unable to find its replication partners. "
Comment: Hi... Thank you for oyur answer. Do you have the an official link of microsoft?


For a new writer, is it better to enter contests or submit to magazines/journals?

Question: I'm a rookie writer, working on short stories thus far, mostly for practice and exposure. I need to get them out there somewhere. They're probably going to mostly fit into Sci-fi, fantasy, horror, weird fiction, etc. Genre stuff, in other words.
So my question is this: at this stage should I enter writing contests or submit to magazines and journals?
I want to get going on this but I'm stuck on issues such as these.
Thanks.
Answer: It is tough to get published in a magazine or journal, but if you want to be a professional writer, I think that's the route to go.  Most writing contests are not terribly high visibility, and quite a lot of them are expensive to enter.  A single solid publishing credit in a reputable magazine is worth more than a hundred awards from contests no one has ever heard from.
Sci-fi and fantasy are fortunate in that there are a number of genre publications devoted to them, some more general, some more targeted.
One caveat:  Publications get so many unsolicited submissions that receiving any feedback at all is unlikely.  If you're still at a beginning stage, you might want to join a writing group, or find some other source of criticism first.  Otherwise, you might just be shouting into the void.
Answer: When I was in graduate school, one of my creative writing instructors suggested we students name awards after one another, win them, and then tell magazine editors about it in our cover letters. The advice was flip, but served to point out that contests are often expensive to enter, whereas magazines don't typically charge reading fees.
In the interest of frugality, I usually steer writers away from awards and encourage them instead to focus on developing their skills in a writing group. Once developed by the group, a piece could be placed in a magazine.
I wish there were a more clear "ladder to success" for writing. Once upon a time, perhaps it was "Start with magazines, then move up to books," but these days I'm less sure. Time spent studying writing in college and graduate school can also be a path, which will improve writing and increase connections in the community of writers.
In more recent years, another mode seems to be developing in which writers gain an audience online with a blog, and then bring that blog to publishers with metrics describing how many unique visitors, etc.
I wish you the best of luck with your endeavors!
Comment: ...or take that blog audience and sell them some self-published stuff. Of course, that just shifts the problem to 'oh god how do I get people to read my blog?'. But, anyway, if I could give you another upvote for suggesting writing groups, I would.
Comment: It does seem like a divide in the road---people who are good at self promotion might do well blogging and making connections on social media, and people who are poor at self-promotion might seek out some of the more traditional modes, impressing editors at publications that will do some of that legwork.
Answer: I think the best way to get started as a writer is to develop a portfolio of professional work.
You can start by doing jobs for free or on sites like hire writers. I wrote an article about how to use the site to get content created and how to use it to make money. Check out the article hopefully it will be useful.
Make Money as a Writer on Hire Writers Marketplace
Also there are articles about getting started as a freelancer on the same domain. They were written by a freelancer so it is sage advice.
To learn about creating a professional content portfolio check out the link.
After you create your portfolio with a professional looking website featuring links to your work, you can develop relationships with editors and pitch them ideas.
Although I fully support the idea of entering contests and submitting work to magazines, it might be more difficult to get paid this way.
Answer: It depends on two things.

What your skill level is.
What you feel comfortable doing.

I began writing with fan fiction and fan fiction contests. (Note: these contests were loose and open. They were not professional, and were simply somewhere to practice and receive criticism.) That's how I learned to write. If you're a beginner, still honing and perfecting your writing process, I believe open community contests may be for you. I would also look into fan fiction on something you're interested in. It's very open, and a great place to test methods out. It also has the added bonus of giving you free criticism, in the form of your readers' comments.
However, if you feel like you know what you're doing, and are just looking to solidify your processes, I would say magazines and journals could be a good way to go. They will give you a good taste of what actually writing a book is like, including the publishing process. You will probably get professional feedback/editing on what you write, and all feedback is invaluable.
Summing up
So it comes down to where you're at, and what you feel comfortable doing. If you're just a beginner, I would recommend contests, and especially fan fiction. If you have a solid process that you use to write and are looking to solidify it, I would recommend magazines or journals.
Disclaimer: I have dabbled extensively in fan fiction and fan fiction contests. I have never gone near magazines or journals, simply because I never felt the need. I honed my processes entirely through fan fiction (and this site).
Answer: The days when you needed to publish in a magazine are long over and thank god. If I had to keep fighting with those annoying lesbian, B- student refugees from Swarthmore over my use of the 3rd person singular anymore at my age I would probably kill myself.
Just go to a copy shop and start printing it. Haven't you heard of samizdat? The Xerox machine is your ticket to freedom. Don't forget to put contact info in the book, so people know how to buy more, but whatever you do, don't use your home address. There are some real crazies out there. Once, one of my friends and his buddy showed up unannounced on the doorstep of Kurt Vonnegut and scared the shit out of him; don't let it happen to you.


When is it worth playing around "s" in Scrabble? I.e., trying not to spell words that "s" can be appended to for a parallel word

Question: I often find myself in situations where I have to choose between a high scoring word where the opponent can stick s to score highly, or if I should pick a lower-scoring word that you can't add "s" at the end of to make a parallel word. I suppose it's different for every board, like depending on tile position and lead, but as a general rule, what cases, if any, should I play around "s"?
Comment: just to avoid the issue of free points, where I play, we have a house rule that you can't add a lone S after an existing word.
Answer: This is a balance between how many points you are scoring now and how many points you can potentially give up. If you play the lower-scoring word, how many points are you losing? Do remember that opponent might not be able to take advantage either, if they don't have an S.
Usually for any square except a triple word score (TWS) tiles, it's not worth giving up many points in order to avoid the potential hook. With TWSes you need a bit more math. How many outstanding tiles are there that can hook? For example if your word is ITCH, then there are exactly four tiles that hook to the end: the two Y's and the two Blanks. If all four tiles have already been used then you should have no qualms about using it. On the other hand there are significantly more tiles that hook to the front of ITCH. Therefore the potential front hook is much more dangerous than the back hook.
Because whether it's worth it to play around an S depends strongly on how many tiles have been used, what the score is (if you're behind you must take chances), etc, it's not possible to give more precise guidelines.
One more tip: if both blanks and three S's have already been used, and you're holding the last S, you should absolutely play the word without the S and keep the hook for a later play.


Is it advisable to use EPDM for flooring around the pool?

Question: I am planning to use EPDM flooring around the pool so that it will provide grip and kids won't get hurt when they fall. But few people said that EPDM does not do well around water. Is there something I am missing. There are few online images that show EPDM around the pool. Can someone suggest
Answer: Anyone who says that "EPDM does not do well around water" is ignorant of what the material is. It is used specifically as a water resistant membrane for roofing and many other applications, including around pool decks.
It is not the material itself that is an issue, it is how you intend to use it and how it is applied/installed. Your question doesn't specify exactly what you intend to do, but assuming that you will have a professionally applied EPDM coating, with the surface properly prepared and the material mixed and applied as required by the manufacturer.
Comment: It is for the deck of the pool not inside the pool.
Comment: We did add epdm. It is working well
Answer: EPDM is the best material for Water or harsh weather. As I understand you are looking for sponge EPDM Sheets to provide cushioning. This will serve your purpose.
However, you can try "EVA Sheets" which are comparatively very-very cheap & can be used for this purpose.


Does 声 exist as a traditional character?

Question: I see that 声 has an entry in the Kangxi dictionary, but every site seems to define 声 as a simplification of 聲. Does 声 also exist as a traditional character? If not, then what's the glyph origin behind 殸?
Answer: Yes,「声」represented the word now written as「磬」(stone chimes).
「声」was originally part of「殸」(stone chimes), and this character later became「磬」. Later on, people began cutting off the components from「聲」(sound) to use「声」as a shorthand for「聲」(sound), but「磬」and「聲」represented different words.

「聲」(sound) is comprised of「殸」(stone chimes being struck) and「耳」(ear).

商甲前7.42.1合集8613春秋金鎛 篆說文解字 今楷
「声」depicts stone chimes「石」suspended with threads/string. In「殸」, a hand holding a striking implement「殳」was added to emphasise that the instrument is meant to be struck. Finally, another semantic「石」(rock, stone) was added on to「殸」, as a further emphasis that the instrument was made of stone.
In the modern form, the threads used for suspending the chimes is written as「士」.

商甲乙3212合集13505商甲乙1277合集376西周金己侯貉子簋集成3977東漢隸景北海碑陰 今楷
「石」was originally a depiction of stone chimes, and its original meaning is stone, rock. A distinguishing symbol「口」was added later to mark the name of an ancient region called「石」, and is inherited in the modern form. The stone chimes component was later simplified into「厂」, then the strokes were further altered slightly into「丆」, resulting in the modern shape.

References:

季旭昇《說文新證》
黃德寬《古文字譜系疏證》
小學堂
中華語文知識庫・漢字源流
國學大師

郭沫若《甲骨文合集》
中國社會科學院考古研究所《殷周金文集成》
Answer: 声 is a pictograph of an old stone instrument.  The radical 殳 is a hand hitting something with a stick.  The ear 耳 below 聲, must represent the hearing of the sound from this instrument being played.  See the book: "China: Empire of Living Symbols" by Cecilia Lindqvist.  If I remember correctly it is in there.
Answer: 殸 led to 聲, but was not composed from 声; it's not like evolution to ever more complexity, sometimes a component is isolated from more complex forms. 声 has been used for a thousand years, if that is "traditional" enough.


What is the false stop in a music piece called?

Question: For example, Watch around 2:10 here. What is this false stop called? is there a single word?
Comment: The accepted answer is good - but let me recommend music.stackexchange for future questions about musical terminology.
Comment: The only term I've heard used is [False Ending](http://en.wikipedia.org/wiki/False_ending)
Answer: In classical music tradition such a dramatic break in the music (not so much a false ending) is called a grand pause, a caesura, or very informally, railroad tracks.
A grand pause is a more expansive break, often notated with a whole measure of rest, sometimes with the initials "G.P." over the bar.
A caesura is typically a shorter break that often happens abruptly.  It's notated with two right-slanting parallel lines (looking like railroad tracks, whence the informal label) that can be placed at any point within the measure.
Your Yanni example is somewhere in the middle of the two, and could be appropriately called either one - either a shorter grand pause or a caesura.
Answer: In music theory, it simply referred to as a whole rest or a blank measure. But in sound engineering and electronic music design, the simulation of a malfunction, false-start/stop etc is referred to as an "edit" which comes from "edited glitch" and is also sometimes shortened to "itch" for the meaning of the word itch and how an intentional error in a composition creates the feeling of an itch that needs to be scratched, the scratch being the point in the composition where the edit resolves itself, having temporarily tricked the listener into thinking that something may have gone wrong.
For wild examples of edits in electronic music, see the works of composer/producer James Holden, especially his piece "a break in the clouds" which was meant to introduce the edit-techno genre as the first release on his record label "border community" -- better still, see his dub remix of Britney Spears' "Breathe on Me" http://www.youtube.com/watch?v=dC7G8LpckhY which is almost 100% edits & itches with ONE final satisfying scratching of the edit-gl/itch.
Comment: Do you have a reference for this?
Comment: https://en.wikipedia.org/wiki/Glitch_%28music%29 is close, points to a lot of relevant things, which, in terms of finding a citation, is probably in an indie record label's mission statement or interview with an electronic musician. only reason i know this particular terminology is that i and/or people with whom i've worked (as the band "meerkat") had to invent a lot of the terminology ourselves. -- (Warp Records is particularly established, you might find a good mission statement there, or something from their artists such as Aphex Twin or Boards of Canada)


How many ways to iterate?

Question: There are 9 coins, out of which one is odd, i.e. its weight is either less or more than that of the other 8 coins. How many iterations of weighing using a pan balance are required to find the odd coin and to find whether it is heavier or lighter?
Answer: We need

 three weighings.

We are trying to distinguish between

 9x2=18 possibilities, and a single weighing gives one of three results, so we certainly need at least three weighings.

Let's begin,

 as n_palum does, by dividing our coins into three sets of three, and weighing one against another. Six possibilities remain in either case.

Now:

 If our two sets balance exactly, then we have three coins A,B,C left, and one of them is the odd one out. Weigh A against B. Now we know either A heavy / B light, or C heavy/C light. In either case, weighing A against C will finish the job.

On the other hand:

 If our two sets don't balance, we have six coins A-F and we know that either one of A,B,C is heavy or one of D,E,F is light. Weigh A+D against B+E. If A+D is heavier then either A is heavy or E is light; weigh A against, say, C and we're done. Similarly if B+E is heavier (this time we'll need to weigh, say, B against C). And if A+D balances B+E then either C is heavy or F is light; again, weighing A against C will finish the job.
Answer: It requires:

 A maximum of 4 weighings. It could be found in 3 as Gareth pointed out.

Explanation:

 Divide the 9 coins into sets of 3 each. Let them be Set 1, Set 2 and Set 3. Weigh Set 1 and Set 2 against each other. If they weigh equal, then Set 3 contains the odd coin. Otherwise, weigh Set 1 against Set 3. If they weigh equal, Set 2 contains the odd coin. If in both cases, they do not weigh equal, then Set 1 contains the odd coin.  Having identified the set with the defective coin in 2 weighings. Repeat this process on individual coins of the found set. This requires a max of 2 more weighings (but could be done in 1). Hence, the odd coin can be found in a maximum of 4 weighs at all times.
Comment: why to divide in 3 sets?
Comment: @nrb I'm sure there are other ways to get to this. This is one.
Comment: There's a typo in this answer.
Answer: Divide the coins into three sets of three. Weigh the first and the second and weigh the second and the third. This will tell you in which set the coin is in and if its heavier or lighter.
From the odd set out take two coins and weigh them. If they are the same then third coin is odd. Else its the one heavier/lighter as per weighing the three sets.
Max weighting = 3.
Comment: Welcome to Puzzling! (Take the **[Tour!](http://puzzling.stackexchange.com/tour)**)  How does your answer add to the identical ones already given? You should always look at existing answers before providing one of your own, to ensure you are not just adding a duplicate. By the way. we generally put Spoiler tags around answers to avoid revealing the answers to someone who wants to try to solve the puzzle on their own.
Answer: Maximum

 4.

Strategy

 Number the coins 1 to 9.
 weigh 1,2,3,4 against 5,6,7,8. (weighing 1)
 If they are balanced,
     then 9 is the culprit and we are done.
     else :
 Weigh 1,2,3 against 4,5,6.  (2)
 If they are balanced then 7 or 8 is fake.
 Weight both of them against 9 and you find the answer.  (3 and 4)
 if 1,2,3 against 4,5,6 are not balanced
 weigh 1 and 5 against  2 and 4.  (3)
 If they are balanced then 3 or 6 is fake.
 swap 4 with 3 on the previous step (4th). If it's balanced then 6 is fake, if not then 3 is fake.
 If 1 and 5 is not balanced with 2 and 4.
 if the side that is heavier is the same as the heavier side in step 2 it means switching sides for 2 and 5 did nothing. so the coins are fair. If the heavy side is the other one it means 2 or 5 is fake.
 now we have one more weighing to find one out of 2 coins.
 weigh one coin in the "wrong" group with coin 9. (4th)
 if they are balanced, it's the other one. If not, it's the one you chose.

How many ways to iterate?


Is a modern dark age possible?

Question: For context, I'm considering a story similar to the Netfilx TV show The 100 in which humanity has to recolonize the Earth following a major extinction-level event. I'm aiming for the society they recreate to be similar to our current one. Everything from technology to cities to daily life is almost identical to ours with the only major difference being geopolitics. So my question is: Is it possible, given a global catastrophic event in which humanity needs to repopulate the Earth, for technological development to "freeze" for, say, 100 years or so since human efforts would be geared towards resettling the Earth? I'm aiming for a modern dark age that doesn't involve the loss of current tech but rather a temporary slow down or halt of technological development. So that, for example, by 2150 or 2200, we've only progressed maybe 40-50 years technologically from where we are now.
Comment: How much do you envisage human population being reduced by the event? Humans don't actually breed very quickly, and recovering from a major loss of population might take much longer than you seem to have provided for. This is not the kind of question that TV writers consider, but SF writers have a more demanding audience.
Comment: @Noah: 500 million left?  But that's around the maximum sustainable population of the Earth, so why would you WANT to increase population?  WRT technology, note that modern technology was developed & manufactured by a very small fraction of the world's population.
Comment: @Noah: Huh?  But 500 million is about the current population of the US and Western Europe combined.  In terms of technology, the rest of the world, and a good fraction of the US+Europe population, is pretty much irrelevant.
Comment: The so-called "Dark Ages" had [*plenty* of technological developments and innovation](https://en.wikipedia.org/wiki/Dark_Ages_(historiography)#Modern_academic_use).  What it **lacked** was widespread documentation or historical records to shed light on what life was like during that time period.  Just because a train enters a tunnel, doesn't mean it stops moving!
Comment: My idea is that human population has been significantly reduced. So, largely, there are those who escaped of world and those who were left behind. I'm thinking that those who escaped off world return come to recolonize but find that there are pockets of civilization that survived and continued. Since the disaster caused efforts to shift from tech development to repopulation, they too as held back technologically. So to give a number, say there are about 500 million left. A fee thousand that have gone to space, a few hundred thousand in underground bunkers/Arks while others just survived expose
Comment: In about 100 years, I figure humanity could stabilize and form various societies geared to reconstruction. Population would begin to recover and it would be all about rebuilding the world that was lost but in a different image.
Comment: Frederick Pohl examined a closely-related problem in *The Coming of the Quantum Cats* (1985): A parallel world was depopulated and available for colonization. The big problems were logistical, not technological. Example: To build shelters you need a sawmill for lumber, but where do you get the required saws and motors from? Where do you get the power to drive those motors from? How do you transport the logs and lumber? Everybody knows the simple answers...but it's long, hard work to build that answer.
Comment: @jamesqf That 500 million figure isn't known by the rest of the world. I'm aiming for a number that I guess isn't as detectable. As for as others are concerned, it's just them. I take it that 500 million isn't a reasonable enough figure.
Comment: "Our best estimates for how many genetically different individuals you need to keep a population going with 95% confidence for 1000 years is around 4169 individuals." – [What should three men and three women do if everyone else is dead?](https://worldbuilding.stackexchange.com/a/3212/799) - Wiki: [Minimum viable population](https://en.wikipedia.org/wiki/Minimum_viable_population)
Comment: 500 Million being the limit is a political statement, not a technological one.
Comment: @jamesqf It was invented by a small fraction of the world's population, but requires an economy of scale to actually maintain.  Modern tech needs satellites, global trade, and VERY expensive equipment.  Without millions of people to consuming the technology to share in these costs, there is no way to back its manufacture and maintenance.
Comment: To build on Chronocidal's statement, they did not necessarily document less either. They just transitioned from bronze and parchment to steel and paper... but bronze and parchment survive the elements MUCH better than steel and paper; so, while we have tons of bronze tools and parchment scrolls left from older times, very few tools and writings have survived from the dark ages because thier stuff (though more advanced for thier purposes) was less durable.
Answer: That a small population can try to resettle the Earth is possible.
That the same population can start from where the technology development went idle is highly unlikely.
First of all most of the knowledge needed to operate today's machinery and systems will be gone. With that will be gone all our logistics and supply chains. After 1700 years we still don't know how Romans made their concrete, for example.
You might say: "well, we don't have coal shipments, but we have books telling us that coal was used to feed power plants". Yes, but most of the mines are not shallow like the ones which were first used at the dawn of the industrial revolution. Again, to operate those you will need modern systems.
That would probably be a permanent hindrance on the development possibilities of this new settling culture.
Comment: Why do you believe that we don't know how Roman concrete was made? It's not some sort of supermagical material. Basically, low-cost Roman concrete was made with gypsum and quick lime, and high-quality Roman concrete was made with [pozzolana](https://en.wikipedia.org/wiki/Pozzolana). The Romans exported vast quantities of pozzolana volcanic dust from Italy to make concrete for the [construction of harbors](https://web.uvic.ca/~jpoleson/New%20Material/Chersonissos%202007/Chersonissos%202001-7%20Web.htm) and other works which justified the use of high-quality concrete.
Comment: Re Roman concrete, why do you think it's relevant today? The Romans didn't understand the principles behind it - various bits of earth from various parts of their empire turned out to have different properties, but that's all they knew. For modern concrete, we know *exactly* what the principles are, so we can recreate it at any point. Historians are interested in how the Romans did it, sure, in the same way as they're also interested in how the Anglo-Saxons built timber-frame huts, but Anglo-Saxon hut-building and Roman concrete-making does not inform modern construction.
Comment: roman concrete has been an active area of research for a long time: https://unews.utah.edu/roman-concrete/   i believe the realization of adding volcanic ash and seawater was a recent breakthrough in understanding how to make it, and why it has some its strengthening properties
Comment: @barbecue No, I do mean it does not inform any construction today whatsoever. Modern concrete is not even slightly influenced by Roman concrete; and whilst some places do still build huts, they do not in any way need to know how the Anglo-Saxons did it.
Comment: I seem to recall that Roman concrete survived pretty much intact in sea water for 2000 years and with our moden understanding we do not know how to make concrete or similar materials that last more than a few decades in sea water.
Comment: @graham perhaps you mean it does not inform modern first-world industrialized construction.
Comment: If you mean the Roman concrete that they used in marine environments: https://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/15190/The-Secret-Ingredient-in-Ancient-Roman-Concrete-is-Seawater.aspx
Comment: @Graham If you really mean that then you'd be wrong, because right now, today, as I'm typing this, there are people constructing buildings without using any modern materials or modern equipment. As I said, you're saying modern when you mean modern industrialized.
Comment: @barbecue I didn't say that no-one is currently building huts. What I did say was that no-one building huts today needs to know how the Anglo-Saxons built theirs. For people currently building without modem materials, historians use that current knowledge to reverse-engineer how people did it in the past. It doesn't go the other way.
Comment: We know how Roman Concrete was made now... We even can explain why it is self healing (Badly ground quick lime, that encourages cracks to develop to the large quick lime chunks, which when exposed to water react and seal the crack...)
Answer: With the exception of a near extinction event, there probably won't be a modern dark ages.
Even the dark ages we heard about in school is considered to be a myth in modern academia. Science still advanced throughout the Middle Ages and wasn't suppressed as much as many people assumed by the Catholic Church. Other civilizations, religious or otherwise, saw scientific advances and a rise in the average lifespan.
Basically, the only way to have a real dark age is to damage the human population to the point where scientific advancements are difficult, if not nearly impossible. There could be an order that suppresses science, but as we learn from the myth of the historical dark ages, you would have to have an order that would repress all scientific advancements for most human civilizations. Otherwise, you will have other civilizations somewhere out there advancing progress (since even if the Dark Ages were real, there would be other groups like the Chinese and Muslims still making scientific discoveries).
There is a rule in biology called the 50/500 rule: a rule that says if everything goes perfectly, you would need about 50 people to survive and carefully breed to prevent inbreeding, and 500 people to prevent genetic problems in future generations. Basically, a disaster that reduces humanity to a few hundred or thousand people rapidly could provide a dark age. This would create a scenario for humans where immediate survival and not inbreeding would take precedence over new discoveries. This temporary small population would make it believable that there are no other people on the planet who would be making massive scientific breakthroughs, and would force any future generations to have to learn basic survival skills before considering any new breakthroughs or progress. The population would also start off small enough to make it nonviable to run factories, mines, and other industrial facilities necessary to maintain modern technology, at least for a few generations.
Answer: There's quite a few good answers already here, so I'd like to focus on the questions itself...
Is it possible, given a global catastrophic event in which humanity needs to repopulate the Earth, for technological development to "freeze" for, say, 100 years or so since human efforts would be geared towards resettling the Earth? I'm aiming for a modern dark age that doesn't involve the loss of current tech but rather a temporary slow down or halt of technological development. So that, for example, by 2150 or 2200, we've only progressed maybe 40-50 years technologically from where we are now.
In the case of a cataclysmic event in which most of the Earth's population is wiped out, there would have to be a very good reason motivating people to continue to try to increase technologically. Since survival would become the most important issue, most of modern technological development would be useless and hence worthless.
For instance, trillions of dollars go into information technology development alone. Trying to make systems larger, more complex, more robust and more user friendly. This all would be useless in a world where there are only hundreds to thousands of people. Consider the defense industry, the space industry, the entertainment industry... All of these industries invest trillions of dollars and contribute enormously to technological development and all of these would be worthless in the scenario given. This can be true for nearly all other branches of technology...when living consists of fighting for survival why put time, energy and resources into anything but trying to rebuild and repopulate?
Thus, while it is possible to keep our current level of technology in the sense that the knowledge can be there...for instance stored in some fashion. There would not be enough people to harness this knowledge, nor enough resources to apply it, let alone resources to further this knowledge.
Thus, depending on who survives and how the rebuild society, I'd expect at first, knowledge to be increasingly lost over time, until the population has increased enough for survival to be a non-issue. Fortunately, with access to all the basic information about how the world works this should not take too long, but will still probably take time scales of hundreds of years and this is assuming no other major cataclysms or wars.
Answer: A near-extinction event such as you propose will have wide-reaching social effects. What caused the near extinction? If the perception of the survivors is that some aspect of the pre-extinction society was the primary cause for all of the deaths, then we can expect that the survivors will not be quick to continue those "deadly" aspects.
If science and technology are thought to have caused the problem, then it does not make sense to ramp up science and technology again. Substitute "lack of religious faith" or "vegan diets" or "too much partisan politics" or "whatever" and watch how society switches to different forms and beliefs.
We humans are quite adept at making up stories to explain the inexpiable. A quick review of mythology, the typical political campaign, and the content of certain cable news channels will disabuse you of the notion that they have to make "rationale" sense. In the situation that you propose, the survivors would not have the time or energy to work through the detailed analysis to get to the "truth."
Enlightened reason, such as we associate with science and technology, might re-emerge after a time, but I would not be surprised if that time was measured in millennia rather than decades.
Answer: A catastrophe such as you describe would produce a rapid reordering of priorities.  Many forms of technology would be cast aside as useless for survival, and often the tools you need to redo them would be lost, but others would get intensive interest and so development.
At the very least, at our technological level of development, research into infertility treatments could continue and would be urgent, both to preserve genetic diversity and to simply increase the population.
Comment: I like what you said. I agree with it most. I was thinking of the situation being where humanity is geared towards a mindset of war but also of that of growth. So a sustained economy geared towards empires and war between them. However, I'm not sure if it conflicts with the enlightened part of us that would rather see humanity prosper as a whole. Not just under one system and sees any attempt to basically destroy humanity or human lives as a criminal offense.
Answer: Not only possible, but pretty much probable even without an extinction event.
The original "dark age" happened in the first place because the life was "good enough" (at least, good enough for those in a position to do research or make inventions). All you need to repeat the feat is to kill the social elevators (that's why deep inequality is considered bad).
Contrary, a great repopulation effort will require (and reward!) new technologies (or even reinventing old ones). It will also make possible a lot of different social experiments. Hardly a dark age recipe.
Answer: The big problem with most extinction level events is that in order to kill enough people to make technology stagnate you have to minimize the population to a point that makes all sorts of existing technology unachievable.  Not just forward progress.  A few hundred people won't run around for more than a few years using computers and cell phones because they will be unable to maintain the space programs required to keep the satellites going.  They will be unable to maintain the multi-billion dollar factories that manufacture them, they will be unable to gather all the exotic materials from across the globe needed in thier construction. They won't even be able to devote the manpower to keep a modern steel mill running.  Since you bring up 100 as an example, your society is pretty much guaranteed to crumble back to the iron age as it did for the surface people with so few people left.  It would then take centuries or even millenia for people to repopulate enough to pick back up where we started.
Modern technology is so heavily reliant on economy of scale and global trade that you need to maintain a world population in the millions to keep it from all falling apart, but millions of people thrust into a harsh new survival scenario will tend to innovate just as fast as a larger more comfortable population because they will have more needs to meet.
These factors together mean that you need an event that does less to cause a population driven dark age, but a cultural one.  One really good way to do this is a robot uprising.  The robots could kill off a large portion of the human population without completely destroying our ability to maintain a modern infrastructure, but the resulting fear of AI would paralyze our ability to technologically progress.  Modern tech is at a point now where nearly every new invention hinges on highly developed computer systems to make happen, but if people fear AI too much to use it, then moving forward past our current levels will slow down to a snail's pace.
To achieve your modern micro population scenario, you could make the AI uprising's devastation asymmetric.  Have some nations that were completely wiped out while others survived mostly intact.  The the surviving nations would need to recolonize the wild zones by first sending small expeditions that may only be in the hundreds.
Answer: If you place the story 20-30 years forward from now, you could use nano-technology aka robots to fill in the gaps. The humans have the knowledge and your robot army does the field work.
We need coal! -> robot mine.
We need to build x -> robot builds.
On a side note; many stories imagine that this will be how future colonization of worlds will work. You can't turn a human off (yet), you can turn off a robot. Besides that their needs are very shallow; power and maintenance. Where as a human has a pletora of needs that need to be met during transit and after planetfall.
Answer: Modern technology requires a long supply chain -- not just physical supply chain but also a chain of specialized knowledge.  Those suppliers don't exist everywhere in the world, and it would take a long time to build up.  For example, over the past 20-30 years China has been building up the supply chain for electronics.  They have not only the device assemblers but also the chip makers and the suppliers of the various raw materials and components.  It has taken decades for them to build the network of companies to dominate that field.  If we decide to try to move those industries back to America, it will also be a project of a few decades.
This can also be seen in other complex industries such as auto manufacturing, pharmaceuticals, etc.  There are many countries without an auto manufacturer.  And you have some countries, like China, that don't yet have an internationally successful car company, but they have lots of the auto parts supply chain.
Simply put, you could create a "dark age" with regards to certain industries, simply by knocking out certain countries in your armageddon scenario.  Without the USA, Japan, Germany, and South Korea, you wouldn't have much of a modern car industry.  There are some car makers in China, India, etc., but you might think of their vehicles as a technological step backwards (to be fair: I haven't taken a test drive of any of these lately) and it might take them several years to catch up to present day expectations or exceed them.
In your "repopulating the earth" story, people could have all the written-down knowledge of the present, but still not be able to duplicate what we can accomplish.  This is the actual case today in many countries.  Vietnam or Cuba or Ireland could check all the engineering books out of any major library but that wouldn't give them an auto industry.  Canadians could learn online how to make decent bacon, but their agriculture just isn't organized for it.
On the other hand, your settlers might find ways to innovate with less infrastructure.  Maybe instead of having a specialized computer chip for every device, they could learn to reproduce one chip (i.e. an Arduino) and utilize it for all kind of different purposes.  So their factories and farms might not look like modern ones or like the ones of our past, but more of a DIY hybrid.

Is a modern dark age possible?


Up to what Mach/Reynolds numbers will Ingenuity be tested?

Question: From an aerodynamics perspective, velocity alone is insufficient to describe the flow regime experienced during flight.  For the Ingenuity helicopter, what specific Mach numbers and Reynolds numbers are planned to be exercised during test flights on Mars?
Comment: Are you asking about the Mach & Reynolds numbers the entire aircraft will reach, or its blades?
Comment: @OrganicMarble: More so the rotational mach number rather than translational, since rotation was likely orders of magnitude larger. Overall, my main motivation is to understand the flow regime experienced in flight and what factors/limitations motivated the choice in flow regime in flight.  Though perhaps that should be its own separate question.
Answer: The maximum rotation rate for the blades is quoted here as $2800\,\mathrm{rpm}$.  However other information variously indicates $2600\,\mathrm{rpm}$ and $2400\,\mathrm{rpm}$: the second figure coming from mars.nasa.gov.
I'll take the lower figure, which seems to be what they're actually using: I presume the higher figures were before they'd worked out what they needed to achieve in practice based on measurements of lift, actual mass and so on.
The total blade length is $1.2\,\mathrm{m}$ so individual blades are $0.6\,\mathrm{m}$ long.
So the tip speed is $2400\times  0.6 \times 2\pi / 60 \approx 150\,\mathrm{ms^{-1}}$.  The speed of sound on Mars seems to be around $244\,\mathrm{ms^{-1}}$, so the tip speed will be about mach $0.6$.
The blades will spin with approximately constant angular velocity with lift being controlled by pitch adjustements, as with any helicopter.  So this is the only regime they will experience during flight.
I imagine they experimented fairly extensively in the hypobaric chambers on Earth, however: there's no reason to believe that there's anything special about the atmosphere on Mars which was not reproduced in those experiments.
Comment: I'm also curious what factors motivated the upper bound on the mach number.  Was it primarily aerodynamic, structural, or power/size/weight limitations that drove the operating point for that mach number.
Comment: @Paul: I don't know.  You *really* don't want the tips to be supersonic though, and I think things get pretty weird well before you get supersonic as parts of the airflow become supersonic or nearly so.


Shimano short cage rear derailleur capacity

Question: Can an Ultegra or 105 short cage RD handle a 30T  ?
Comment: There's been 25+ years of 105 setups. It will change depending on which 105 you're talking about. In any case, just go to shimano's website and read the data sheet.
Comment: I'm not a Shimano person, but I've heard some Shimano derailleurs have the capacity stamped on them. Does it?
Comment: In most cases a 28T shimano mech will run a 30T rear fine.
Comment: Shimano has been very good about stamping the model number on their components over the years, so it is easy to get that number and find just about anything you'd want to know. On rear derailleurs, the number is usually stamped on the side of the parallelogram facing the wheel, and will read something like "RD-5800".
Answer: As I said in a comment, there are 25+ years of 105 and Ultegra (well, ultegra was called something else back then, but the line has been around for quite a while), so you need to find the right 105/Ultegra you're talking about.
You can find the Product Info at this link.
In 11 speed: The Ultegra RD-6800-SS and 105 RD-5800 SS both have a 28t max. Thus, Shimano doesn't recommend you run a 30t with a short cage. The RD-6800-GS and RD-5800-GS both have a max of 32t.
In 10 speed: The 105 RD-5701-SS has a 30t max.
Note that Shimano has mucked up cable pulls between 10 and 11 speed road, so you can't just put a 10 speed RD in a 11 speed system.
Note that also there may be several RD's under the same group under the same year or # of speeds (e.g. in the Sora case), so you need to look up the particular RD you want to use.
Comment: I'm using a 2005 or 2006 Shimano 105 RD-5600.  It is officially rated 27T maximum sprocket.  I'm using a 28T and it shifts perfectly.  Just wondering if it could handle a 30T.
Answer: For the 5800, short cage can only take 28t but I wonder this too after seeing this.
Comment: Thanks.  Looks like he loosened the B tension screw to lower the jockey pulley and is able to have a 32T lowest gear.
Answer: It's worth mentioning that most max tooth specs are on the conservative side. Meaning that if you put your drive train into inappropriate combinations you would expect problems if you used a cog bigger than recommended. If you already know not to use the gear combos of "little cog in the front, little cog in the back," and, "big cog in the front, big cog in the back," then you could squeeze a bigger rear cog. Of course this is not recommended, but it's fun to know and play around with.
Answer: I currently have a 105 1x10 setup with a 42t front chainring and have used 11-34 and 11-36 Deore cassettes.
Comment: Also, derailleur capacity is the amount of slack the derailleur can take from *both* the front chainring difference and the big-small cog difference. In a 1x, you will naturally be able to handle a bigger cassette than in a 2x setup.
Comment: But what size is your rear derailleur?


Does the weight of the battery count as "fuel" in a battery powered ultralight?

Question: 14 CFR 103 compliant powered aircraft should be less than 254 pounds (excluding fuel). Do the batteries account for fuel in case of electric engine?
Comment: IMO batteries cannot be counted as 'fuel' as 'fuel' is consumed as .the flight progress. Battery does not :)
Answer: The jury (i.e. FAA) is still out on this question as of early June 2014.  FAA has indicated it will not give a gasoline "fuel allowance" to be credited against weight for batteries.  Given that fuel weighs 6 lbs. per gallon, or 30 lbs. for the maximum legal gas an ultralight can carry, it would be a somewhat negligible, but certainly welcome, allowance for would-be electric manufacturers.
One company, Chip Erwin of AeroMarine, has imported a barebones ultralight motorglider based on the Goat towed ultralight glider.  It's called the Zigolo, and carries batteries enough for 30-40 mins. of flight, without exceeding the 254-lb. weight limit of the part 103 category.
In time the FAA may well decide to grant the allowance.  It's still not going to amount to much more time, maybe 10 minutes given current battery energy density, which is a fraction of the energy density of gasoline, but research into electric storage is at a feverish pace worldwide.
Look for sport, then commercial electric aircraft, within the next 5 to 10 years.  Several electric single and two-seat electrics are already flying.  The Airbus ducted fan, recently ballyhooed as the first electric aircraft, which it certainly isn't, is a promising look at one way commercial electric applications might come to market.
Comment: Consider making a permanent account, without knowing the specifics you definitly SOUND like you can speak somewhat authoritatively on part 103... :)
Answer: No. The FAA was approached about this in 2012 and responded that there was no allowance for battery weight. All batteries must be included in the 254lb airframe weight.

Although batteries may indeed be used to provide power to an electric motor, the FAA does
  not agree that those batteries should be equated to usable fuel and excluded from an
  ultralight vehicle's empty weight.

https://rainbowaviation.company/wp-content/uploads/2017/08/elect-103-battry-def.pdf September 4, 2012
Comment: The FAA response seems lackluster since they seem to feel that any allowance of batteries equates to an unlimited allowance. That's disappointingly lacking in imagination. As such, I wonder if there is some wiggle room. Clearly, the intention is that a ULM can have as much as 7kg more than its empty mass, since it can carry fuel in addition to empty weight. There are EU self-launching gliders such as the Atos Wing and the Birdy which are 120kg, putting them just heavier than the max Part 103 empty limit, but under the 254lbs + 2.5gal of fuel and with only several minutes of endurance.
Answer: There seems to be consensus that built-in batteries count against the weight, but  removable batteries might raise questions that are unanswered to date. If it's not integral to the plane, it might be argued to fit the spirit of the rule.
Comment: This answer could be improved by adding some sources to back it up.  Welcome to Aviation.SE!


Is a Captive Portal Wifi AP as insecure as an open unencrypted Wifi?

Question: As far as I understand, the captive portal is implemented by some sort of iptable firewall rules. Since there is no handshake established during the initial association with the AP(As no passphrase is required), does it mean that all subsequent traffic will be sent unencrypted even after the user has authenticated via the captive portal?(Which means that an attacker can sniff all traffic and inject arbitrary packets)
Comment: Yes you are right. This also means someone can hijack an authenticated user's session (by faking their MAC address) and impersonate them to the eyes of the AP which could have policy/legal implications (spam, downloading/hosting illegal content, etc).
Answer: Yes, wireless networks protected only by a captive portal are unsecured. They work by denying access to websites other than the captive portal until the connected device, identified by MAC address, has clicked through the portal. Requests to non-HTTPS sites made through the network are sent in the clear, the same as an entirely open network.


What is the usage of 고 있다 in this example?

Question: What's the usage of 고 있다 in this case?
The normal usage is to state that the act mentioned in the preceding statement is continued but it doesn't seem fit this example.
Answer: Here, 놀고 있어 is not a declaration, but a command: it's the same as 놀고 있어라.
So the meaning is something like "Go keep playing over there."
There is not much practical difference between 놀아(라) and 놀고 있어(라) here - after all, mom is telling the kids to keep playing - but 놀고 있어 sounds softer to me, which fits the situation better.  Essentially, mom is saying "Thanks, but it's OK if you keep playing."
In other context, there can be a difference in meaning: e.g., if I say 공을 던져, I'm asking to throw the ball, presumably once.  If I say 공을 던지고 있어, then I'm clearly asking to keep throwing the ball (or balls) multiple times.
Answer: 있다 can be used as an auxiliary verb behind another verb, like -고 있다.
It means that the action that the front verb indicate is continuing or the result of the action keeps going.
So when the mom said "놀고 있어", she told her child to continue playing.
Other examples,
먼저 먹고 있어. 금방 다녀올게. Please keep eating this first. I will be right back.
TV 보고 있어. 거의 다왔어. Please keep watching TV. I'm almost there.


Is Flash a good rapid prototyping tool for UX

Question: Is Flash a good rapid prototyping tool for UX?
Comment: Okay, I'm really sorry but I need to say this. Flash is not a good tool for anything. From past experience, it encourages poor coding standards, increases user-frustration and is no match for  - Anyhow, I just found this link: *http://www.adaptivepath.com/ideas/rapid-prototyping-tools* It seems to have a pretty good list, however I'm not sure which ones are Flash-based.
Comment: depends on what you are prototyping. If you are prototyping a Flash app, then it's perfect!
Answer: Flash is a great prototyping tool, if you're producing a Flash website.
If you're prototyping a HTML website it is less effective because you're presenting a model to the stakeholders that can't be realised in practice.
Matt
Comment: That's only true if either your site isn't an AJAX site or the person designing the prototype doesn't know the limitations of AJAX from that of Flash. There's enough of an overlap between Flash and AJAX that Flash or Flash Catalyst would be an acceptable tool for prototyping many web apps.
Answer: A lot of effort small reward. You can port vectors from fireworks to flash if there's a chance you'll end up in flash world or not but I think fireworks is better than flash if rich prototyping is what you're after http://www.guuui.com/posting.php?id=2112
Comment: That might be true for certain sites, but I'm willing to bet that it takes less time to build a prototype of an AJAX interface using Flash Catalyst than creating the visual components in Fireworks and then coding the HTML, CSS, and JavaScript.
Answer: I think Flash IDE is great for prototyping. Not wireframing but prototyping. It is especially good for prototyping ajax like interactions. Even though they might be implemented in HTML/JavaScript later on. Flash IDE could help you to visualize inline interactions so the stakeholders and developers could understand how it works. If you need to create a user scenario/flow you could use insitui.com it is an online tool that will help you dump your thoughts on a serious of linked screens and it will help the team to understand user flows before you get into the details.
Answer: If you're following an agile methodology and looking for a quick hit, why not consider some of the products that allow some level of prototyping to be built along with wireframing your application/site?
On Mac, Omnigraffle has some crude clickthrough capabilities in presentation mode, even allowing the loading of canvas layers to mimic states for the same page.  Or you can build very solid rapid prototypes using Axure, which comes in Win and Mac variants.
There are also several online applications that do this to one degree or other.  Take a look at Balsamiq, iPlotz as starters.  Still others like Creately work pretty well too.
As for Flash, why on earth would you even consider that when you are looking for 'rapid' ... won't even go into the usability issues.
Answer: The Flash Builder IDE is one of the most painful environment I've ever had the displeasure to work on. I would suggest anything, but. I find Java Swing in Eclipse very simple to throw some simple together with.
Comment: Interesting. I've used Flash Builder pretty extensively and haven't run into many issues personally. I would be comfortable using it.
Answer: If you are looking for something to create highly interactive prototypes with you might also want to check out LiveCode by RunRev (http://www.runrev.com/products/livecode/). It supports delivery on a wide-range of platforms, including Mac, Windows, Web, iOS, and a very early beta for Android.
The programming language is fairly user friendly, and the storyboard (card) metaphor works very well for the purpose of building scenario-based prototypes.
Comment: LiveCode seems to have a similar design goal to Appcelerator Titanium. Have you ever compared the two?
Comment: I did also look at Appcelerator Titanium, but it seemed to have a steeper learning curve for what I wanted to use the tool for (occasional interactive prototypes).
Answer: This is like asking if a piano is good for a musician to write songs with.  The answer is, "It depends if they know how to play piano."  If they are a guitarist, the answer is no.  If they are writing a song for the harp, the answer is no.  If they need to do it while flying on an airplane, the answer is no.  If they don't own a piano, the answer is no.
Flash is a tool.  If you are proficient in it, and the output is Flash, and you have a copy of it on your computer, and you think it's a good choice, then sure, why not.
Answer: If you're just looking to create wireframe mockups for your UI, I would recommend one of Balsamiq's tools.
If developing a Flash/RIA site, Flash Builder isn't too hard to work with in my opinion. I wouldn't use it to mock up a regular HTML web site though.
Answer: Depends on what you need to prototype and also your production environment and workflow. If you need to prototype with high visual fidelity, require animations or video (or more generally speaking: a cinematic feel), do not need to handle very complex structures and don't know how to code basic Javascript, than Flash Catalyst(!!!) might well be amongst the better choices. If you need to prototype Flash websites (cough…), Flash kiosk systems or Air RIAs, than of course, the Flash IDE or respectively Flash Catalyst are probably ideal. Personally, I try to avoid especially the hostile UX hell of the Flash IDE (and of Adobe's buggy bloatware in general) as well as I can, but tastes may vary…
For websites in general I would definitely NOT recommend it in any case, though – native is most often best. For mobile and tablet apps, Webkit kicks quite some ass, and for anything that requires more advanced capabilites (e.g. exhibition installations), I would highly prefer to use e.g. Processing or openFrameworks.
Answer: Wow. Quite a lot of anti flash-sentiment here. The answer is that it depends on your skill resource, if they are any good then they can present behaviour in flash to mimic any environment very quickly.
Axure and the like are very limited to present hi fi solutions for user testing for any projects aside from next page functionality.
SO the answer is theortically its a brilliant option if you have access to the skillset, if you dont, then dont.
Comment: It's not anti flash sentiment. It's anti "using a different medium to prototype the medium you are actually trying to build". It's not a skillset issue...it's an issue of prototyping in the the context of the actual product.


Can I recover deleted images from Capture One's proxy files?

Question: I lost some of my RAW files and I am unable to recover them. Is it possible to somehow at least recover JPEGs from Capture One's proxy files?
Answer: If we are talking about a catalog, the answer is: Yes and no.
Full disclosure: I have no idea if there is a chance when using sessions (never used one) or if there are some highly-specialized programs that might do the trick - at least my Google-Fu did not reveal any ground-breaking program for the job. Also, consider trying some recovery tools - avoid writing to the disk where your RAWs were stored before to increase your chances!

I tried it with all file-types inside <YOUR_CATALOG>\Cache. IrfanView, which I consider to be a very open-minded program, can open the *.cot - files and claims that they are JPEGs with wrong endings - however, they appear to be thumbnail-sized only (around 300px on the long edge).
I then tried to open all other file-types (*.cof, *.bc, *.cop) with 7-Zip - also to no avail.
XnViewMP failed with all those formats. FFmpeg, on the other hand, was able to read the *.cot and opens up *.cof as well - though it only shows what appears to be random noise.

However:
One solution is to make a screenshot of the preview in Capture One - depending on your settings, this should far supersede the 300px thumbnails IrfanView can open, but it is a very time-consuming process.
Unfortunately, Capture One cannot export offline media only with their thumbnail available, as this Q&A suggests:

While offline, you can still make adjustments and organize images as Capture One does not require the raw file for these actions and will use the cached preview file. However, it is not possible to zoom in past the preview size, process/export or create an LCC from an offline file.
Answer: If you're working in a session-
No.
The preview proxies (.cop files) are in fact rendered image files (since they are the previews you see in the Viewer panes. Without source files, the session can't reference anything to process.
If you're working in a catalog-
Somewhat.
Since the source files are gone, the images will be marked Offline. You can, however, leverage those preview files (which are within the catalog package) and process to the QuickProof JPG format. This format essentially takes the preview files and uses them as the source data to generate JPG files. This data is limited to the size you have set in Preferences > Image > Cache Preview, but generally it's big enough for web.


What is the difference between "responsibility" and "obligation"?

Question: I must admit that I am confused with these two words. For so long a time, I have been using them interchangeably. I have consulted the dictionary (of course) but I can't seem to pinpoint the glaring difference between the two (if there is any). This may be similar to this question.
Comment: Which dictionary and what are your points of confusion? More context needed as well.
Comment: Also as your linked answer suggests, you can have a look first https://www.google.com/search?q=obligation+vs+resposibility
Answer: In many ways they are the same thing, but the "angle" is slightly different. Responsibilities are more intrinsic, as opposed to obligations. The latter, I think, is more something you have towards your environment, society,... surrondings basically. Allow me to explain why I see it like this:
If you have children, you are responsible for them, and therefore, you have the moral obligation to take care of them to the best of your abilities.
Note that you are responsible and this results in an obligation (in this case, a moral one).
Equally so, taking good care of your kids means good education, which in turn results in your being obligated to get them ready for school, help them if they need help, and, of course, pay for the tools the need (books, bills and the like)
In that respect, responsibilities are somewhat intrinsic to life: you are responsible for your own health and well being (eg: smoking is being somewhat irresponsible/reckless towards your own health).
If you, like me, are a smoker and have kids, I'd say you are obligated to smoke outside of the house, in order not to damage their health.
Your responsibilities are yours, but they result in obligations towards both yourself and your environment, or even society.
Sure, you might be given responsibilities. At work, or by people you care about, but these situations suppose a contract of sorts: a social or legally binding contract, which implies, in turn obligations. Basically: Responsibility and Obligation "go together like Horse and carriage, love and marriage": you can't have one without the other.
The inverse applies here, too: you are obliged to obey the law, if you don't, that causes harm to the society. If you get caught, and appear in front of a judge, you'll be held accountable for your actions (you are responsible for your actions, if you're a sane person).
So, a responsibility is something you can be held accountable for. How much you actually take responsibility for thinks, is evident from how you deal with your resulting obligations.
Answer: Being responsible means you have a sense of moral or ethical duty to something or someone which may imply an obligation to do something.
An obligation is simply a mandate to do something that does not connote any moral or ethical dimension.
Comment: Not according to AHD, for instance.
Comment: Isn't there a case to be made to say that, when you're obliged to do something (given your definition), that automatically translates to responsibility? An elected or appointed gouvernment official is given a mandate, and with it comes responsibility/moral duty. That's why I feel as if they are intertwined, and even though an obligation alone does not imply morals or ethics per se, an obligation translates to responsibility when applied to a person
Comment: you could be obligated to do something against your will or better judgement, could you not?
Comment: Yes, like an impounder might feel sorry for the people he meets during his working hours, and feel as if he has to do something _"morally gray"_ from time to time. He/she does have a responsibility towards his employer, the people who are owed money and indeed his family. The obligation is the factual aspect, devoid of any moral or ethical dimensions, yes. The moral and ethics of the situation are perhaps better described as that persons responsibilities. You've got to bring home the bacon
Answer: AHD includes these senses for 'obligation':

a. A social, legal, or moral requirement, such as a duty, contract, or promise that compels one to follow or avoid a particular course of
  action. b. A course of action imposed by society, law, or conscience
  by which one is bound or restricted.

Thus in some cases, because one has a social or moral requirement but not a legal one say to perform some service, it could be argued that the person has and has not got an obligation to do it. The confusion of 'polysemy + hypernymy'. Sometimes, the compounds / collocations 'moral obligation', 'legal obligation' and 'social obligation' are used to specify the sense intended.
The senses of 'responsibility', as you infer, overlap to a large degree with those of 'obligation', but carry a little less of a legal flavour. Though if a contract you've signed says 'It is the client's responsibility to . . .', certainly don't assume that's not a legal requirement / obligation.
Answer: I think that a responsibility is usually something you can take up or are given the duty of:
She had the responsibility of locking the doors.
An obligation is something that you may not refuse to do.
He had the obligation of paying a 5% carbon tax for his fuel.


Washing coolant system with dish soap to remove oil residue

Question: Someone mentioned it is a good idea to wash the coolant system with dish soap to remove residue oil.  I was wondering if that is true or can it have any side effects?
Comment: Perhaps some context would be helpful here. Are you recovering from a blown head gasket or something similar where you know you had some quantity of oil in your cooling system, or are you considering this as routine/preventative maintenance?
Comment: routine/preventive
Answer: I'm assuming that this person was advocating putting a small amount of dish soap in the water used to do a coolant system flush.
I would not do this to my car as routine/preventative maintenance, I would simply use water for a flush. My concern would be that any dish soap residue remaining in the system may adversely affect the chemistry of the coolant, potentially impacting its ability to prevent corrosion or cool the car. I doubt the chemists are checking to make sure their coolant is unaffected by dish soap.
There are purpose-made coolant system flush solutions marketed by coolant manufacturers. Presumably these are safe with the coolant chemistry, but unless I had reason to suspect above-normal levels of contamination/corrosion in the coolant system, I would simply use water rather than spend money on multiple gallons of special flush fluid that I would then have to dispose of properly.
Plain water from a garden hose is a common flush recommendation. Castrol, for example recommends water.
Answer: Never ever do such things as adding dish soap to the coolant system to flush. Any soap in the system may start eating the engine blocks and could cause a catastrophic failure. Just flush the whole system a couple times with distilled water or bottled water if you really want to flush the system and use a 50000 mile warranty coolant.
Answer: Cooling systems do have contradictory requirements; Take for example the coolant pump seal. In order to last, the seal faces require some lubrication, otherwise, the usual anti-corrosión compounds present in every coolant will eventually precipitate on the seal faces (a hot place), dry out and start to erode the faces.  Adding a water pump lubricant (that essentially is a soluble oil, similar to the one used on lathes to cool the cutting tool) solves the lubrication of the seal, but contributes to add an oily coating along the cooling system, reducing the heat transfer.
In another topic, the contributor (Dodgethesteamroller) posted an excellent procedure for cleaning and flushing the system with Citric acid. His first recommendation makes sense: before the citric acid, one must get rid of any oily film, to allow the acid to reach the scaled Surface inside the block.
Contrary to the unjustified worry of mac above, dishwasher detergents simply cannot damage the metals used in the engine (otherwise the detergent dould immediately ruin aluminum cooking pans, cast iron skillets and the like!). Dishwasher detergents are not very alkaline or corrosive enough when disolved in water, and thus are safe to remove any oily film, allowing the citric acid to attack the alkaline scale deposits.  I have performed the procedure suggested by Dodgethesteamroller and he is right when he said that after the citric acid is flushed with water, I saw a quantity of scale granules comming out of the block (from a 2002 Dodge Stratus R/T Sedan 2.4L Turbo, that always have used the proper 5-year HOAT coolant from MOPAR,even changed before the complete period).  The problem now, is that small quantities of scale keep loosening and comming out even after 6 water flushes. I used the citric acid that comes in the "Prestone Heavy Duty Flush", and put the Neutralizer (Sodium Carbonate) after water flushing the citric acid. (The Prestone HD flush is packed inside a cardboard "can". The upper part contains 255 grams of citric acid, while the lower third contains the sodium carbonate neutralizer.  That's the part where I disagree with Dodgethesteamroller, because he said "use TWO pound of citric acid..." and I had difficulty trying to disolve the little over one half pound into one gallon of hot water!  Even using an electric kitchen mixer, about 5% of the citric acid poder settled without getting dissolved. (I reason that in order to dissolve two full pounds, one would need about five gallons of water, which is an amount too big to fill a car system!


About "Preparation for a non-academic career"

Question: I was just about to ask a question having to do with "Preparation for a non-academic career". Specifically, I was going to ask how an academic can tell what's the salary range for a potential research position in the hi-tech industry (generally or in some region). Noticing the interdiction in the tour, I didn't ask that - but is it really off-topic? I mean, it is a problem mostly unique to academic researches.
Comment: I don't see that you've asked it yet, so I'll comment here.  There are sites that provide such information, e.g. glass door.  You might find the information you need there.
Answer: That is intended to discourage people outside of academia from asking questions about "what's the best degree to become a sailboat repairman?" Historically, we have tended to allow questions about where academics can find employment other industries.
To that extent, ask away, says I.
Comment: I will also note the part in the "on topic" help page: "anyone in or interested in research-related or research-adjacent fields."


What does the word 「こいや」 mean?

Question: The full sentence is 「ちょっと こいや」.
Comment: Since no one has mentioned it in his answer, I am going to mention it here.  It is the tough guy's imperative.  Everyone says "Come here." in English, but only a limited number of people would say 「ちょっとこいや。」 in Japanese.
Answer: It's not a word on its own, but a combination of 来い (imperative "come") and や (see #3 in this dictionary entry).
As l'électeur pointed out in the comments, it can be understood as a "tough guy's imperative."
Answer: This means come here and it is quite casual.
Answer: As l'électeur said, it definitely shows tough guy's commanding nature. For example consider the following statement:

そんなの忘れてちょっくら晩飯でも食いにこいや。
Forget your troubles for a while and come and
  have dinner with us.

In the statement above

ちょっくら means a little
晩飯 or ばんめし means dinner
食い or くい means eating

As you can understand from the context, the speaker's statement has somewhat demanding/commanding nuance attached to it. I think if you understand the nuance, you will understand how and when to use it.

What does the word 「こいや」 mean?