Can I get a Kodachrome-film look in my digital photos after editing?

Question: Can I edit my digital photos so they will get the colors and the values of the famous Kodachrome film or at least resemble to it? I can also ask the futile question edit the photos so they have a Leica look?
Comment: Related: [Slides in the digital era](https://photo.stackexchange.com/q/119634/15871)
Answer: You can emulate target color profiles to alter an image to look like other known profiles. You can do this manually or you can leverage profiles developed by other people. You'll have more flexibility editing RAW than JPG.
For example: Classic K14 Lightroom Preset
I used to shoot a lot of Kodachrome. When the shot was right it could be fabulous, but it was contrasty and intolerant of exposure error and dynamic range.
Kodachrome still has a warm place in my heart, but Digital Rules!


Would a pool of petroleum explode if lit on fire?

Question: A large pool of crude oil 60 feet in diameter and about 10 feet deep. It sits atop a 100ft. tall stone pillar with a 5ft radius hole that leads down into the earth. If the oil on top is exposed to a flame, would it just light up the surface, cause an explosion on the surface or blow up the entire pillar?
Also does which of the above scenarios or any other depend on the size of the flame?
Comment: Setting fire to a pool of crude is possible but not very easy because generally speaking crude oil liquid does not burn. It need to be heated, or sprayed, or vaporized to really do the fire thing in air. (then it is self-sustaining+, of course)
Comment: What does the "5ft radius hole" have to do with the rest of the assembly? Does oil come up through it?
Comment: It burns (once you get it lit, which isn't all that easy).  It's just an oil well fire.
Comment: It depends here's a smaller version with kerosene https://www.youtube.com/watch?v=ga43J2ByPrs  Here is gasoline on water https://www.youtube.com/watch?v=RqiggAI2Jds
Comment: At worst you'd get a giant candle. Now, if someone were to push a pressurised jet of of air into the 5' hole...
Answer: This paper talks about combustion

It is the fact that combustion properties of large-scale crude oil pool fire have great significance for security design and firefighting of current crude oil reserves. Burning rate, the flame shape and radiation intensity are the most important parameters for fires properties.

And this is an image of a fire on an oil spill in the Arctic

To have an explosion you would need to have finely dispersed droplets of oil in the air to greatly increase the combustion efficiency. With a calm pool that doesn't happen.

Incidentally, this is why it is dangerous to try to extinguish a flame in a frying pan with water: the water will sink below the frying oil, turn into vapor and explode nebulizing the oil above it and producing a fireball/explosion.
Comment: @KeithMorrison: In common vernacular usage, "make a giant fireball" and "explode" are considered synonymous. I'm sure this annoys pyro experts to no end, but it's how the language is used in practice. Personally, I blame Hollywood (which employs many of said pyro experts in the first place!).
Comment: A grease fire doesn't "explode" (as in, there is no concussive force). It flares up and splatters around, it doesn't detonate or deflagrate.
Comment: Yeah, well firefighters don't use that language (as I would know, being a fire chief).
Comment: @KeithMorrison If the water turned to steam fast enough, you could have a steam explosion that in turn causes a fuel/air explosion by aerosolizing the grease.
Comment: @KeithMorrison A grease fire is driven by two main processes. Rapid vaporization of water, followed by adiabatic expansion of the fuel air mix. Given that both, fuel-air bombs AND steam explosions exists, and they are both explosions. I would say that this is an explosion. Specifically a deflagration. You seem to be confused with high/low explosives or deflagration/detonation, all of which are explosions.
Comment: @nick012000, that doesn't happen in a kitchen fire. There are online videos where you can see demonstrations of it.
Answer: Less volatile hydrocarbons = less flammability
Imagine you decide to pour a puddle of gasoline and light it.  It burns merrily and you dance around it in your typical frenzied manner.  Once it is gone you pour another puddle, but fatigue claims you.  You go inside, resolved to come out, light the puddle and dance in the morning.
In the morning (after your tea; you are not a barbarian!) you go out, matches in hand.  But your puddle?  There is nothing left but some greasy scum.  All of the volatile low molecular weight hydrocarbons have evaporated.   You cannot get it to light.  Your dancing is perfunctory and uninspired.
Crude oil is a mix of hydrocarbons ranging from gases (methane is the lightest) all the way up to asphaltenes (petroleum jelly aka Vaseline being a purified example).  When it comes out of the ground it is all mixed up and so the light gasoline-type fractions are available to catch fire.  Once they heat up the rest the whole thing could burn.
If you let it sit out, molecules leave into the air according to their volatility.  What is left is increasingly high molecular weight molecules and difficult to ignite except with high temperatures.  You will wind up with something like the La Brea tar pits which I conclude are very hard to light on fire since I think every resident of Los Angeles has tried a few times.
The solution:  your pool of oil was not filled up by a guy with a bucket and a tall ladder.  This pool is connected to a reservoir deep underground.  It is contiguous with that reservoir.  The stuff at the top turns over.  Light fractions move up thru the column and bubble away.  Heavy fractions slink back down into the earth.  The whole thing is replenished from below.  The height of the column is necessary to balance the pressure from below.  Really it is an oil well.
Now you can have a fire.  The fresh stuff will burn.  As it burns away the pressure on top decreases and more will come up from below.  It will keep burning.  It will also make a ton of greasy smoke.  It will be an oil well fire.

source
Comment: My kids just watched Bigfoot Family yesterday... if only their writers would have thought of this, they could have avoided a very painful plot hole.
Answer: Having lit quite a number of petroleum pools on fire for training purposes to teach people how to put such a fire out, no, it will not explode. The vapour at the top will burn, heating and vaporizing the fuel below which will likewise burn when it reaches oxygen, until such time as the pool is burned away.
The only way to cause said pool to explode would be to, well, drop an explosive in it, which would throw the liquid into the air in a fine mist which could then be ignited to cause a fuel-air explosion.
Comment: Contrast this with the experience of using the incinerator (3'x4'x12') in that same building to burn off old paper goods. The original natural gas fuel source had been disabled, so we had to throw in logs to get it going. I once tossed in a quarter cup of gas to move things along faster. In the time required to close the door, strike the match, open the door, and throw it in, it evaporated enough to explode, knocking me (hard) on my can and rattling the window behind me so hard I thought it would break.  It was only a quarter-cup, but man, that was stupid.
Comment: This is an important answer. I was thinking about having once bought a building that had an old, external diesel fuel tank. The tank was half-full (about 10 gallons) but had stood there for years. With the fire department's blessing, we elected to burn it off. It took forever... absolutely forever... because getting diesel to evaporate to the point of explosion even with the presence of flame is no small thing. Oil would be a thousand times worse. I can't even imagine the OP's conditions resulting in an explosion. It would burn, certainly, but not explode. (\*continued\*)


3D Cursor always goes to where I click

Question: Doesn't matter if it's selected or not, but whenever I click LMB, the cursor always appears there. It's also preventing me from selecting objects by clicking; I can only drag select, and it sucks trying to select a single object through bunches of them. I've been able to blend on other devices without this issue. How do I turn this off?
Answer: In Blender is a default setting that 3D cursor keybind is LMB. In that case, you can select objects by RMB. You can easily switch these two in the settings.
Comment: Blender community worked hard on 2.8, some of the updates really ruined our blending habits.
Answer: In Blender 2.79 and before, the cursor is supposed to go wherever you click with LMB.
In Blender 2.80+, left-clicking selects the object. Right-clicking will give you editing options for the object selected.
Also in 2.8+, the cursor should not go wherever you click with LMB.
What most likely happened, is that you accidentally have "Cursor" selected in the left panel, so that wherever you click, the cursor follows.
You can fix this by selecting the arrow icon in the left panel.

3D Cursor always goes to where I click


How hard is it to create a monero wallet site?

Question: There aren't a lot of monero based sites around, and I think there is a lot of opportunity, but I don't really know much about implementing crytocurrency into a website. I figured I might try to start by creating a wallet site, but I wanted to ask if anyone could provide any insight onto the difficulty of that? I may be way in over my head but I'm not sure.
Comment: Do you mean a full wallet website where users can receive and make payments? How confident are you that you can provide a website that is secure and will adequately protect your users' wallets? You can't do 99% secure: you must aim at 100% secure and that requires time, knowledge and experience.
Comment: There is an online wallet mymonero.com which I read somewhere will be opensouce sometime in the future. I can say it is safe since you don't store your spent keys/private keys on the server. Your keys are generated on the client and transactions I think are signed locally on the client browser then submitted (not too sure yet). This means that you will not worry too much on securing your server. One downside of this online wallet is that if you created your wallet somewhere and restore your wallet it would not be able to see previous transactions. You have the option to pay where it would scan
Comment: @Gundamlancer in general mymonero.com is quite safe, since it doesn't send your seed or private spend keys to the server. However, if an attacker would compromise the server, they could change the source code to get your seed (or private spend keys). Also due to SSL authority flaws I would possibly not exclude a Man in the middle attack. I trust fluffypony, that he cares a lot about security of his server and the service in general, but I wouldn't hold tons of Moneroj there.
Answer: It would be moderately easy to get a working wallet site provided you know some basic programming (python, php, node.js) and a little about web server usage (linux!).
You just need to run a full node on your server, create a wallet, then write some code which checks for payments, makes payments etc. See wallet-RPC for some guidance on this.
As already mentioned, the challenge here would be to implement these things securely/reliably. Making something like this for public use is not recommended unless you know exactly what you are doing. Just imagine if all your users monero was stolen or lost - you'll certainly end up in hot water.
You're right though that there is a lot of opportunity in this space. I encourage you to at least experiment with your idea (i.e get a full node working on your server and programmatically check your balance). Its the best way to learn and from there you'll have a better feeling of what you can do with this technology.
Comment: Thank you for this, was definitely the kind of answer I was looking for. I get the point that the other person made about how it would be rather difficult to have a safe/secure service. But I would definitely like to experiment with it and see how everything works.


Why aren't my Destiny 2 Campaigns saved on my steam account?

Question: So basically, I just got a steam account and started playing Destiny 2 on my computer. My original account that I would play Destiny 2 on is on my Xbox. So I decided to do the cross save feature so I can save my stats on both platforms. All my loot and stuff is on my steam account but the campaigns that I bought on Xbox are not there and it says I have to buy it again. I bought Forsaken, Beyond Light and The Witch Queen all on Xbox.
Comment: Was any of this content listed during the transfer on either Battle.net or Steam side? Did you have XBox Game Pass when you transferred, and if so which sub level? Have you tried to start the process to buy them on Steam, and if so what happens? IDK personally, but this info may help someone more knowledgeable (based on a XB to PC data transfer guide).
Answer: Campaign licenses are per platform. If you bought them on Xbox you will need to buy a game expansion again on Steam.
Currently (Witch Queen / Season of the Risen) the campaigns you mention are in the Destiny Content Vault.
This is detailed in the guide
https://help.bungie.net/hc/en-us/articles/360049498031-Destiny-2-Cross-Save-Guide

DLC licenses, such as Beyond Light or Shadowkeep, do not transfer between platform accounts with Cross Save. Players who wish to access DLC on platforms they play on will need to purchase that DLC on that platform.

The existing answer to this question has more details Destiny 2 cross save between PC and XBone, do I need to buy expansions for both

Why aren’t my Destiny 2 Campaigns saved on my steam account?


About soldering wire for sophicated instruments

Question: What kind of soldering wire is used for soldering sophisticated instruments Like Transmission electron Microscopy (TEM) or electrochemical instruments? Is any high quality or alloy free wire required?
Answer: TL;DR - Use 63/37 Tin-Lead solder whenever possible. It has been extensively tested for reliability and is the preferred alloy for aerospace and military applications.

To answer this fully and correctly we would need to know a great deal more about the specific components used, operational conditions, and needs for ROHS compliance. Base metals, solder working temperature, and operational temperature/conditions can all play a part.
In general terms, you will want to select a eutectic alloy for any high reliability need. Without getting too bogged down in technicals, "eutectic" means it transitions directly between solid and liquid at a single temperature. This improves reliability by dramatically limiting the chances of inconsistencies and micro-fractures in the joint.
Assuming there is nothing that would exclude the use of leaded solder (e.g. ROHS compliance, high operational temp) or otherwise require special alternative alloys (e.g. silver or gold base metal), 63/37 Sn/Pb is almost always the best choice. It's eutectic, relatively low cost, has a low working temperature, and has extremely low odds of tin whisker formation.
The field of lead-free solder is a rapidly developing one and too broad to approach recommendations without far more info. Since it is a relatively young field, reliability testing documentation is limited and often contradictory. Suffice to say if you don't need it, don't use it. If you do need it, you will need to do some research as to which of near countless alloy choices will be best suited for your application. 95.6/3.5/0.9 Sn/Ag/Cu is determined by NIST to be truly eutectic, so it may be a good place to start.


How do networks protocols communicate with each other?

Question: We know that before sending information, TCP has to establish a connection with another host. So, does the request from TCP get encapsulated by lower levels of stack protocols or is it just sent directly to another host?
Comment: This [animation may help you](http://www.practicalnetworking.net/series/packet-traveling/osi-model/#encap-decap)
Comment: Yes, of course. Each higher layer is encapsulated by the next lower layer in the network stack.
Comment: I think you understand about the need for encapsulation by the lower layers, for TCP data traffic, and you're asking specifically about TCP control signaling like for connection establishment, right? If so, please see my answer below.
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer.
Answer: If I'm not mistaken, it looks like the confusion that the OP has is not with ordinary TCP data traffic once the TCP connection is established, but the TCP control signaling.
The OP writes

before sending information, TCP has to establish a connection with another host

which looks like the context, followed by:

So, does the request from TCP get encapsulated by lower levels of stack protocols or is it just sent directly to another host?

So the question is, for the connection establishment signalling, is that also encapsulated by lower layers of the protocol stack (as is what happens in normal TCP data traffic), or is it sent directly, without the need for the encapsulation by lower layers?
The answer is, yes. Consider the SYN segment in the 3-way handshake for TCP connection establishment. It is like an ordinary TCP segment except for a few important differences (e.g., see RFC 793):

There are 6 control bits every TCP header, one of which is for SYN. In a SYN segment, that bit would be set.
There is a 32-bit sequence number in every TCP header. This is normally the sequence number of the first data octet in this segment, except for the SYN segment. In the case of SYN, the sequence number is the initial sequence number (ISN).
Rather than carrying actual data in the data octets, for SYN, it is specified that "the first data octet is ISN+1"

So why can't the special segments like SYN in the 3-way handshake be sent "directly", bypassing the lower layers? We cannot send them directly, as the IP layer below would not know how to route these TCP control signalling segments! Sure, we could have invented some other ways to do the routing in a different way for these segments, but we already have the IP layer with IP routing and encapsulation of TCP segments, and that works well for packet delivery, so we just re-use all that infrastructure.
Answer: Actually, a request is something that only exists in the application layer, like an HTTP GET request. That request is encapsulated by a TCP segment (or multiple ones).
Each TCP segment (transport layer) is encapsulated in an IPv4 or IPv6 packet (network layer). Each IP packet is in turn encapsulated in e.g. an Ethernet frame (link layer)[1]. An Ethernet frame is line encoded and sent over the wire as bits or symbols (physical layer).
The process reverses on the other side and the GET request is recovered.
[1] An IP packet may be fragmented and transported using multiple frames when it is too large to fit into a single frame (MTU).
Answer: So each layer is separate from each other in the OSI model. If you take an HTTP request/response it's basically a string of bytes sent and then a string of bytes received. This is wrapped in a tcp header with, amongst other things, source and destination IP. This is then, in the case of Ethernet, wrapped in an Ethernet frame (with a source and destination MAC address) and put on the wire. A receiving device will pick it up if the destination matches its own mac and unwrap the frame. Then depending on if it's a router than needs to forward the tcp packet it might rewrap that in another frame and send it to another device or if it is the end host and matches the destination IP then it will use the destination port to pass the contents of the packet to the correct application.
Answer: When it comes to TCP protocal before connection initiate TCP handshake will initiate . TCP syn & syn ack &ack handshake complete . The. SSL handshake begins after SSL handshake completes  actuall application data will be transferred in encrypted format. As TCP is reliable protocal. If any packet in queue is waiting entire queue will be waiting  because in TCP new packet will be intimated after receiving acknowledgement for old packet .
When it comes to udp packet it's non realible protocol. All voice communication comes under udp protocol


Lenovo ThinkPad T61 drivers for Windows 7 after clean install

Question: I am going to clean install windows 7 upgrade version on my Thinkpad T61(currently running Windows Vista) without any bloatwares like ThinkVantage software. I am worried about the drivers. I mean what are the important drivers i should download first to get my system going after the machine is formatted.
Answer: I found all the drivers I needed at the Lenovo site for my recent upgrade of my T61. I did a clean install of 7 Ultimate.  Once I had the NIC and video drivers loaded from a USB stick, I downloaded the Lenovo maintenance package that includes the update applet.   This found all other drivers and updates. The TPM driver and one other that escaped me were a pain.  They appeared to install but still showed as "unknown" finally extracted package and ran manually.  That did the trick.  Works great now.  Some of the latest updates to the tools seem improved
Comment: I would second the recommendation to download and install the Lenovo ThinkVantage Toolbox.  This will allow you to selectively install critical things like drivers and the hard drive protection services (stops the HD from spinning if dropped while it is running) and not software you would consider bloat such as Rescue and Recovery.  It is also easy to keep the drivers up to date and manage the battery.
Comment: Can you expand on which of Lenovo's sw is critical?  What would I install for a clear-cut improvement over what's available from Microsoft via Windows Update?
Comment: @BrianFinkel Get all drivers from Lenovo.  Don't use Winodws update drivers in most cases.  Windows Update video drivers have caused grief more than once.  Video and LAN are ones I get every time so you havea good display and connectivity.  Get Thinkvantage update tool as well.  It works very well and saves a great deal of time.
Answer: I did a clean install of Windows 7 64-bit on my Thinkpad recently. Windows recognized all my hardware out of the box. Saved me the trouble of installing Lenovo bloatware. A few optional Lenovo drivers appeared in Windows Update (under optional updates), but I chose not to install them.
Answer: It takes a little digging but lenovo has drivers on their site - IBM no longer maintains the thinkpad support and driver site - though the drivers for that specfic model seem incomplete for windows 7 but if there's a missing driver, windows update or the vista driver should do the trick. I would note that my R61 of similar vintage works perfectly with no additional drivers on windows 7, using the windows update driver
Answer: Lenovo had posted some instructions on their website for how to do this. The page has since been deleted but an archived version is available.


valve stem caps on tubeless tires

Question: On my road bicycle with tubed tires ridden only on paved roads, I never used the caps that covered the tube stems. Now that I have switched to road tubeless tires, do I need to use the caps to reduce any air leakage?
Answer: I'm not opening up the caps vs. no caps discussion but I think the main purpose is to protect the valves from dirt/contamination and damage rather than sealing it. I never tried but I'm pretty certain a valve cap wouldn't hold in several bars of pressure when the valve leaks or gets loose.
So you may use it but if you haven't seen any benefit with tubes and your riding profile hasn't changed (more dirt riding), I think you can leave them off, it's a Presta valve as used on every tube.
You could make an argument that tubeless valves stay longer on the bike because you don't swap them like tubes and thus, protection matters more than on "throwaway" tubes where you tend to replace them due to punctures from time to time. Also, some premium valves have nice metal caps you might want to keep on for the looks, but that's rather subjective.

Related: Does the plastic cap on a Presta valve serve any purpose once fitted to a rim?
(I am team caps off and haven't had any issues whatsoever, but you do you...)
Comment: In fact, external contamination shouldn't really get in to a closed Presta valve anyway.
Comment: @WeiwenNg I never had an issue in years without but I tried to keep it neutral, it is still the internet and a divisive topic.
Comment: @Criggie The only reason I could see is that a tubeless valve is less of a throwaway item than a tube and thus longer exposed to the elements but from what I've heard the main problem is still valves clogged with sealant rather than aging on the bike and failing due to lack of caps.  Another might be that premium valves come with metal/alloy caps rather than cheap plastic and there is an aesthetic aspect of keeping them on.
Comment: My main use of the caps is to protect the tube from the valve while its all folded up in my bag, before installation.
Answer: Valve stem caps do not (directly) have anything to do with air retention, they exist to protect the valve stem and possibly valve core from damage and debris, and also to protect any attached tube during storage.
For a Presta valve, as long as you have the nut on the valve core tightened down properly and the valve itself is still good, no air is going to leak out of the valve irrespective of whether the cap is there or not. External contamination is unlikely to be an issue for properly closed Presta valves as well, irrespective of the presence or absence of a valve stem cap, though damage from debris impacts is still possible (albeit relatively unlikely).
For a Schrader valve, if the cap is not there a debris impact from just the right angle might have sufficient force to depress the poppet in the valve core and allow some air to escape, though this is not particularly likely, and the more likely issue due to the lack of a valve stem cap is debris fouling up the area in the valve stem above the valve core.

valve stem caps on tubeless tires


An error occurred while installing ZenTest (4.8.2), and Bundler cannot continue.

Question: When I practice the Chapter three of the tutorial of Ruby on Rails. After mostly static pages: conclusion. I tried to push my app to heroku but an error showed up as below: (I searched this error everywhere but can not get a solution)
Counting objects: 96, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (73/73), done.
Writing objects: 100% (79/79), 8.92 KiB, done.
Total 79 (delta 35), reused 0 (delta 0)

-----> Heroku receiving push
-----> Ruby/Rails app detected
-----> Installing dependencies using Bundler version 1.2.1
       Running: bundle install --without development:test --path vendor/bundle --binstubs bin/ --deployment
       Fetching gem metadata from https://rubygems.org/.........
       Fetching gem metadata from https://rubygems.org/..
       Installing rake (0.8.7)
       Installing ZenTest (4.8.2)
       Gem::InstallError: ZenTest requires RubyGems version ~> 1.8. Try 'gem update --system' to update RubyGems itself.
       An error occurred while installing ZenTest (4.8.2), and Bundler cannot continue.
       Make sure that `gem install ZenTest -v '4.8.2'` succeeds before bundling.
 !
 !     Failed to install gems via Bundler.
 !
 !     Heroku push rejected, failed to compile Ruby/rails app

To firstname.lastname@example.com:stark-tundra-9366.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'firstname.lastname@example.com:stark-tundra-9366.git'

My Gemfile is like this:
source 'https://rubygems.org'

gem 'rails', '3.2.8'

gem 'sqlite3', :group => [:development, :test]

gem 'rb-fsevent', '~> 0.9.1'
gem "ZenTest", "~> 4.8.2"
gem 'rake', '~> 0.8.7'

group :development, :test do
  gem 'guard-spork', '1.2.0'
  gem 'spork', '0.9.2'
end

group :production do
  gem 'thin'
  gem 'pg'
end

group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'
  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

group :development do
  gem 'rspec-rails', '2.11.0'
end

group :text do
  gem 'rspec', '2.11.0'
  gem 'webrat', '0.7.2'
end

I don't know what's wrong with this app. I changed the Zentest version and put into test or production, it didn't work.
Answer: ZenTest seems to have limited the newest rubygems allowed. The solution for it is to update ZenTest, as well as rubygems, as newest ZenTest seems to work better.


How do members of the SuperUser community coordinate to close a question?

Question: I'm really curious as to how SuperUser community members, with the proper reputation, coordinate to vote and close a question. It seems like they are closed so fast I don't even have time to defend it. Are they litteraly pinging each other to close a specific question or do they have something they are montioring?
Comment: I'm an addict who reads every single new question if I can. I guess it's the same for the others :)
Comment: What you should really be asking is "how do superuser community members coordinate to reopen questions"
Comment: At your current reputation level, you can't even see pending votes to close your question. So how would you want to defend it?
Answer: Well, there's no real 'coordination' to close questions. There is however a tab in the review page for questions with votes to close and a vote to close chatroom.
On the other hand, it takes 5 votes to close a question, and any >3000 vote user can do so. It just tends to happen on its own.
On the other hand  if you felt a question was closed, but shouldn't have, take a look around meta, work out a compelling arguement and post it here.There's 4 pages of these questions (as of the time this question was rewritten) and if you can convince people to reopen it, there's less of a chance it'll be closed.
Answer: There are various ways. Some I can think of:

The question happens to attract enough views on the front page and is subsequently closed
The question is flagged by a user and the flag is handled by a moderator (or other 3k users who add their vote)
The question is posted in a chat room, which will give it more exposure.
Users with 10k reputation have special tools available to check existing close votes and follow up on that
Users have review privileges and are allowed to see a list of questions that are about to be closed and add their vote

In your concrete case, the question had a flag sitting on it and was discussed on chat, which would have migrated it pretty fast. In fact, the community is quite fast when it comes to migrating questions that seem to fit better elsewhere.
Let me say though that there's nobody insisting that a question should be closed. Even though you can bring attention to it, five users (or one moderator) actually have to agree that it should be closed. And even then, it can be reopened.
If you have trouble understanding what flagging is, how moderators do their work, and what privileges are, please read our FAQ more carefully. Also, check out the FAQ on Meta Stack Overflow: FAQ for Stack Exchange sites
Comment: Here are the chat messages related to your question: http://chat.stackexchange.com/transcript/message/4962804#4962804
Answer: There is a chat room for this, but most of the time we just see the questions. Feel free to comment, or post here, or flag for moderator attention if you think that the post has closed unfairly.
Comment: By posting here you mean referencing the link to my question in a comment to this question? So if I click the flag icon it will bring to a moderators attention who will then comment back? Who are the moderators?
Comment: In order: I mean a post saying something like "what was *insert link here* closed as .... Yes, that is what flagging is for, the current moderators are: http://meta.superuser.com/users/4377/sathya http://meta.superuser.com/users/307/random http://meta.superuser.com/users/1548/ivo-flipse http://meta.superuser.com/users/6574/studiohack http://meta.superuser.com/users/39366/dma57361 http://meta.superuser.com/users/2553/troggy
Comment: Your question was reopened @daniellopez46.
Comment: @soandos: You might want to link to the bottom of [this page](http://www.superuser.com/about), for instance, you forgot nhinkle. :)
Comment: @TomWijsman, thanks, I knew that page was somewhere, but could not find it.


How to determine if two numbers can be used to arithmetically find any arbitrary number?

Question: Say you had a scale, with two weights of two different values used to balance it. Is there any way to determine if two given weights could be used to weigh any arbitrary object? For example, say the weights are 5 and 12 ounces. Is there any way to prove that these weights could be added to both sides of the scale in any possible combination so that an equilibrium could be reached if an object of any weight was being weighed?
Comment: the gcd is one. meaning, if you have an unlimited supply of weights, you can correctly weigh any number of ounces.
Answer: Assuming you have lots of each kind of weight, you can weigh any multiple of the greatest common divisor of the weights.  Here that is $1$ ounce.  Bezout's identity tells you so.
Answer: Notice that $5 \times 5 - 12 \times 2 = 1$.
Therefore, if you have an object of $n$ ounce, you can always put $2n$ objects of $12$ ounce on the same side, and $5n$ objects of $5$ ounce on the other side:
$$n+(2n)(12) = (5n)(25)$$
This is possible because $5$ and $12$ are co-prime.

In general, Bézout's identity states that, for integers $a$ and $b$ with GCD $g$, it is possible only for multiples of $g$. In the previous case, $5$ and $12$ are co-prime, so their GCD $g$ is $1$, so it is possible for any integer, since any integer is a multiple of $1$.


Cable required for pulling 3 phase power outdoors

Question: Might be stupid questions but what kind of cable I for pulling 3 phase power outdoors around 10 meters outside. Frost is not an issue but even if I pull the cable within a pipe there is a good chance of moisture over its life.
Comment: According to code underground conduit is considered to be full of water all the time. The wire requirements reflect that.
Comment: Yeah, definitely bury it, preferably in conduit, not like what they did at Fukushima when they just draped across the ground to save units 2 and 3, and they took physical damage and put em put of business.
Comment: Cool cable sorted. Turns out that only type of 3 phase 5 cable sold in my local hardware store was the on mentioned for outdoor usage because the common use cases here are household EV charging and 400V patio heaters. People pull outdoor cable to induction hubs as well just in case.
Comment: Also I was advised not only to burry cable (in fact violation of building code here) but to pull it using pipe sleeve so physical damage ist threatening the cable ether.
Answer: If you run conduit ("pipe" intended for electrical wire protection) you generally use individual wires, NOT cable (several wires bundled in an outer jacket) - they pull easier than a cable, and the conduit is all the outer jacket required, and a better one than a cable has.
Your local standards are undoubtedly in line with most others worldwide in considering any exterior conduit to be full of water all the time. As such, wiring for use in such conduit is "wet-rated" and works perfectly well in water. Your local electrical supplier will have such wire.
If the conduit is to be buried, there are likely standards for minimum burial depth (which may vary with what type of conduit it is) and how it is to be marked. If it is above ground, but below ~2.5m height there are likely standards for what type of conduit is considered sturdy enough for use exposed to damage. I am familiar with those standards in my local area but not in the Netherlands (location per your other question) - however, I'm tolerably certain that such standards will exist locally.
Answer: You would need wire for a wet location so a common type, at least here in the USA, would be THHW or THWN. You might have to check with your suppliers for equivalent types.


Is there a word or a term for when a story's ending is very similar or the same as its beginning?

Question: In the novel Perfume, by Patrick Süskind, it is notable that the main character appears in the same setting and scenario in the beginning of the novel and in the end. Is there a word for when this happens in novel or TV shows?
Comment: Did he thus *come full circle*?
Comment: no. There is a certain character development, but he comes back to the place of his birth, where he also dies.
Answer: This is called bookending or the bookends technique.  One explanation is at eHow  This technique is also used in speaking.  See Andrew Dlugan's speaking blog for a good article.  I try to use this technique whenever possible when I write a speech, especially motivational/inspirational speeches.
Bookending is a form of a callback.  A callback is when some part of a story, speech, etc., refers back to something earlier.


Software for sorting images based on the image data (not file type)

Question: I have a bunch of photos that I have recovered from a corrupted hard drive and I need some way to sort them because all of my personal photos are mixed in with the operating system and application photos. I can't sort by file type because they are all of the same file type (png's or jpeg's) the only distinction between the images is just the image itself. Is there any software out there that can look at the image data alone.
Answer: You can use the built in features of OS X to help you narrow down your personal images from system and application images.
AFAIK most Application images and system images are not going to be large. Or wider then either 512 pixels or 1024 pixels.
So I assume all the files are in single folder and your personal ones are taken on a camera or Smart phone so will be of a larger size.
Use Command +F keys to bring up the search options for the open window of the folder.

Set up your search criteria too.
Kind is Image.
And either of the below or a combination.
File size is greater than 300kb
Pixel width is greater than 512
And so on.

There are many more options to use for the search under the other.. menu.

You can then move the ones remaining in the results out into a another folder.
Use iPhoto to import the potential personal ones for you final check
Hopefully you will only have a few that are not.
Comment: @markhynte thanks for the detailed answer. I am going to try your suggestions and see how I make out.


Use of capital letters in credits

Question: Does anyone know why on TV show's credits a lot of times the actor's first name is lower case and their last name is done in all caps?
Comment: Just a stylistic choice.
Comment: Do you have some examples for that? That seems rather unusual to me. (Though, at the end of the day it likely just comes down to the specific style the showmakers try to go for.)
Answer: This is a standard practice on French productions, or with French crews, since it is traditional in French culture to write names with the first name in lowercase letters and the last name in UPPERCASE letters. Other productions may have adopted this style for artistic or legibility reasons.
Comment: It is common on forms to be asked to write the last name ("nom de famille" or family name) in uppercase for readibility.
Answer: It's really just a design choice.
Part of the reason is that it makes the big blocks of text in the credits a bit easier to read and easier on the eye. Also, an actors surname can be considered the more important identifier than their first name. For example if I say Brando, Chaplin, Olivier, Nicholson, De Niro, Pacino, etc. etc. you know immediately who I am talking about.
Similarly, in many countries actors unions require professional actors to have a unique name to avoid any possible confusion as their name is a key part of their professional credibility. In many cases, they will stick with their given first name and pick a distinctive surname if their original name is already taken or they just want something which sounds better.
Equally, it is fairy common practice to refer to actors by their surname in reviews and other theatrical journalism.

Use of capital letters in credits


Journey not firing when adding filters

Question: I am trying to set up a journey that our patients start when their opportunity enters a certain stage. However, I want it filtered to a specific list of treatment options. When I leave off the filters and just use the entry criteria "Opportunity:StageName EQUALS In Discussion" people are entered into it just fine, but as soon as I add the filters to the specific treatment plan options, my entries are always zero.
Any insight would be appreciated!
Answer: If the journey is injecting prior to adding that additional criteria, then we can rule out the Marketing Cloud Connect integration being an issue in the sense that it isn't communicating between the clouds. Can you confirm how you are updating this related object field to meet entry criteria? Is this being done manually or is it done via an automated process? If automated, it is possible that the JB Flow is running prior to the field being updated, which will prevent it from being injected. If the value already is populated on an already created record when you activate the journey, then it will not inject unless you update that field.
If you are updating this field manually, I would run Debug logs to see if there is any additional details that you can find. It might also be a good idea to create a support case with Marketing Cloud Support.
With integrated Journey Builder injection issues, there can be multiple things that can prevent injections, so unfortunately there isn't always a clear cut answer. Hope this helps!
Comment: Thanks for the information! We are updating all fields manually at this time, and the planned treatment field is updated prior to the stage being changed. I will run the logs and see if I can gain any further info.

Journey not firing when adding filters


Prove that $∡ADI=90°$

Question: Let $ABC$ be a scalene triangle. $I$ is incenter. Common point of inscribed circle and $BC$ is $E$. $AF$ is angle bisector. If circumcircles of $ABC$ and $AEF$ meet at $A$ and $D$, then prove $∡ADI=90°$. MY TRY: I chased angle. And got little value of result. I have found out $∡CDE=∡EDB=∡BAF=∡FAC$. And other than this I can only tell $ABCD$ and $ADEF$ are circumcircle.
Comment: Where exactly is the point $F$ on the angle bisector of $\angle B$
Comment: It is AF. I mean AF is angle bisector my bad sorry. F is at BC
Answer: Something is definitely wrong with the question.
Checking out:

$\triangle ABC$ be a scalene triangle.
$I$ is incenter.
Common point of inscribed circle and $BC$ is $E$.
$BF$ is angle bisector.
Circumcircles of $\triangle ABC$ and $\triangle AEF$ meet at $A$ and $D$.

The image:

clearly illustrate that
$\angle ADI$ is not anywhere near $90^\circ$.
Comment: oh sorry my bad AF is angle bisector
Comment: Hello how did you draw the picture. What kinf of application di you use
Comment: @Ualibek Nurgulan: Yes, with $AF$ as a bisector it looks OK. I added a corrected image to he question.
Comment: @Ualibek Nurgulan:the picture was prepared using
[Asymptote](http://asymptote.sourceforge.net/),
"Asymptote is a powerful descriptive vector graphics language
that provides a natural coordinate-based framework for technical drawing.
Labels and equations are typeset with LaTeX, for high-quality PostScript output."
Also, you can check out [this forum](https://tex.stackexchange.com/questions/tagged/asymptote).
Answer: Denote by $k_0$ the circumscribed circle of triangle $ABC$ and by $k_1$ the circumcircle of triangle $AEF$, where by assumption $k_0 \cap k_1 = \{A, D\}$. Extend the angle bisector $AF$ until it intersects the circumcircle $k_0$ of $ABC$ into the second point $L$ on $k_0$, the first being $A$. Then $L$ is the midpoint of the arc of $k_0$ between the points $B$ and $C$ that does not contain point $A$, because $AL$ is the angle bisector of angle $\angle \, BAC$. Therefore $LB = LC$. After some very simple angle chasing, one can show that $\angle\, LBI = \angle\, LIB$, which means that the triangle $BLI$ is isosceles with $LB = LI$. Thus we have that $$LB = LC = LI$$
Construct the circle $\omega$ with center $L$ and radius $LB$. Then the three points $B, \, C,\, I$ lie on $\omega$.
If you perform inversion with respect to $\omega$, the circle $k_0$ is mapped to the line $BC$ and in particular the point $A$ is mapped to the point $F$. However, both points $A$ and $F$ lie on circle $k_1$, which means that circle $k_1$ is mapped to itself under the inversion in $\omega$ (and is in fact orthogonal to $\omega$). Since $k_0 \cap k_1 = \{A, D\}$ their image under the inversion with respect to $\omega $ is $BC \cap k_1 = \{F, E\}$ which means that the point $E$ is mapped to the point $D$ under the inversion and the points $D, E$ and $L$ are collinear.
Now, consider circle $k_2$ circumscribed around triangle $EFI$. Since $IE \, \perp \, BC$  we see that $\angle\, IEF = 90^{\circ}$, which means that the center $O_2$ of $k_2$ is the midpoint of segment $IF$ so $O_2$ lies on the angle bisector $AL$ and thus the points $L, \, O_2,\,  I$ are collinear. Hence circle $k_2$ is tangent to circle $\omega$ at point $I$. Under inversion in $\omega$, the circle $k_2$ is mapped to the circle $k_3$ passing through the image points $I, \, A, \, D$ of points $I, \, F, \, E$ respectively, and $k_3$ is also tangent to $\omega$ at point $I$. Hence the center of $k_3$ must be collinear with the the centers $L$ and $O_2$ of $\omega$ and $k_2$, which lie on the angle bisector $AL$, so the center of $k_3$ also lies on $AL$ and therefore the center of $k_3$ lies on the segment $AI$. The latter fact however means that $AI$ is a diameter of $k_3$. Since, as already established, $D$ lies on $k_3$, angle $\angle \, ADI = 90^{\circ}$.
Answer: The problem in the OP can be stated equivalently in the form: The circles $\odot(ABC)$, $\odot(AEF)$, and the circle with diameter $AI$ have a common chord. (Which is $AD$ in the OP.) The first and the third in the list are "simpler" (for my taste, they depend on "simpler points"), so let $D'$ be their intersection, let us try to show that the third circle, $\odot(AEF)$ also passes through $D'$. (So $D=D'$ in the final.)
As it often happens in problems involving essentially the centers $O,I$ (of the circumcircle and the incircle) of a triangle, the following constellation of points is useful:
wiki page on Euler's formula
The following solution is based on the point $L$ from the above link (and the solution by inversion of Futurologist), and on the projection $Z$ of $I$ on the $A$-height. The idea of the following solution is to show that $L,E,Z,D'$ are collinear.

In the following picture, let $AH$ be the height in $A$, $H\in BC$, let $X,Y,Z$ be the projections of $I$ on $AB$, $BC$, $AH$.
(So $EYX$ is the incircle.)
Let $S$ be the mid point of $AI$. Let $\odot(S)$ be the circle centered in $S$ with diameter $AI$.
Let $D'\ne A$ be the second intersection of the circles $\odot(ABC)=\odot(O)$ and $\odot(AXZIY)=\odot(S)$.

We have:
$$
\begin{aligned}
\widehat{LD'A}
&=
\widehat{LBA}
=
\widehat{LBC} + \widehat{CBA} = \frac 12 \hat A+\hat B\ ,
\\
\widehat{ZIA}
&=
\widehat{BFA}
=
\frac 12\overset{\frown}{AB}
+
\frac 12\overset{\frown}{LC}
=\hat C+\frac 12 A\ ,
\\
\widehat{ZD'A}
&=
180^\circ -\widehat{ZIA}
=180^\circ -\left(\hat C+\frac 12 A\right)
=\frac 12 \hat A+\hat B
=\widehat{LD'A}\ .
\end{aligned}
$$
So $L,Z,D'$ are on the same line. Let us show now that $E$ is also on this line. For this, we compute two proportions, this seems to be the quick+dirty path:
$$
\begin{aligned}
\frac{IE}{AZ}
&=
\frac{ZH}{AZ}
=
\frac{FI}{IA}
=
\frac{BF}{BA}
=
\frac{ac/(b+c)}c
=
\frac a{b+c}
\ ,\\[2mm]
\frac{LI}{IA}
&=
\frac{LB}{LA}
=
\frac{\sin\widehat{BAL}}{\sin\widehat{ABL}}
=
\frac{\sin(\hat A/2)}{\sin(\hat A/2+\hat B)}
=
\frac{2\sin(\hat A/2)\cos(\hat A/2)}{2\sin(\hat A/2+\hat B)\cos(\hat A/2)}
\\
&=
\frac{\sin\hat A}{\sin\hat B+\sin\hat C}
=\frac a{b+c}\ .
\end{aligned}
$$
So $\Delta LIE\sim\Delta LAZ$ (since the above proportions are equal, and the angles in $I$ and $A$ are correspondent), so they have the same angle in $L$, so $L,E,Z$ colinear.

We can now conclude. The quadrilaterals $ZIAD'$ and $EFAD'$ have the same angles, so the second one is also cyclic, as the first one. This means that $AD'$ is also a chord in $\odot(AD'XZIY)$. (So $D=D'$.)
$\square$

Bonus: With the notations from the picture, $S$ is on $MN$. The circle $\odot(S)$, and the lines $CI$, $EX$ intersect in a point. The circle $\odot(S)$, and the lines $BI$, $EY$ intersect in a point.

Prove that $∡ADI=90°$


How to make content display on their proper pages on search engines

Question: So my site has a blog and gallery, both working the same way. There's an index, and each post has a permalink going to the individual entry. However, if I search for some of the content on Google, often it returns a link to the index, just because it happened to have been on the first page when it was crawled, instead of the individual post pages. This is especially true in cases of images. How can I make it so that Google returns the proper pages for the posts instead of just the main page of my site? My whole site is custom php code I made.
Comment: Can you provide a link to your site, this sort of thing could be caused by a wide variety of problems.
Comment: Have you submitted a sitemap? If so, how long ago?
Comment: Have u different metas in the  for for each entry or all the same like the index?
Comment: dendory.net/blog
Answer: Some people actually put a no-index directive on their blog index page, that is a drastic step, but could make sense particularly for the gallery.
Another thing you could do is post excepts instead of listing the entire post on the index page.
Getting deep links to the individual posts from other sites would help.


Error with dummy payment processor and email receipts

Question: I set up a contribution page and trying it out I got an error message

Payment Processor Error message :Failed to update contribution in
database

and was taken back to the payment confirmation page, though the contribution appears to be recorded as "complete". It's the first time I've used email receipts on contribution pages (though they have been fine on event pages. Taking out the email receipt gets rid of the error. I was using the dummy payment processor, but if I switch to PayPal then all is fine so I'm guessing its a bug in the dummy payment processor.
I'm on CiviCRM 5.35.1 so an obvious thing to try is the latest version, but I don't have time to test that right now. I can work round it for demonstrating what I want to do by using PayPal and then refunding, but it's annoying.
Answer: Could you check the Outbound email setting is not set to 'Disable Outbound Email'? And the Environment is production?
In case you don't want emails to go out you could set Outbound email to Redirect to Database
Comment: That's not the issue as there is no error and the email goes when I am using the PayPal payment processor and in plenty of other situations. The problem is only with the dummy payment processor selected.


Cara Pils Dextrine

Question: Want to use Cara Pils-Dextrine in my next brew to add body and aid in head retention. I have not made the jump to all grain yet, and I am doing a partial mash.  Will steeping/mini-mashing Cara Pils like a specialty grain work, or do I need to do a full mash to get my desired results?
Answer: Short Answer
Steeping CaraPils is fine.
The Reasoning
One of the goals of mashing is conversion, which breaks down starches present in grain to sugars that yeast can eat.  Some malts are converted in the malting process making it unnecessary to mash for conversion. The HomebrewTalk wiki lists "mash req'd" column on their malts chart indicating which malts must be mashed to convert.
Comment: Light caramel malts, including carapils, are not fully converted during the stewing (mash-in-the-husk) process. Steeping anything under about 30L will add unconverted starches. Whether they will add _enough_ unconverted starches to cause problems is another matter, and many extract recipes take a "who really cares, go ahead and steep carapils" approach. But you're still adding starches.
Answer: I think its important to point out the differences between steeping and mini/partial mashing.
You can steep cara-pils, but keep it to less than 5% of the grain bill as you'll probably add too much uncoverted starch.
However, if you really mean mash the carapils, then you can go whole hog and use what ever % you want.
Answer: You can steep it or use dextrin (same thing).  It's the other white powder.  Cheers.

Cara Pils Dextrine


I have no UART on my microcontroller so how can I add one?

Question: I am using a ATMEGA32HVB microcontroller which has a facility for cell balancing by which we can connnect 4 batteries in series and use one at a time. That is  very useful for power management so I can't use a different microcontroller. Please suggest some methods to add a UART to it so I can easily interface to serial devices.
Comment: The software UART way as described by user26129 is called **bit-banging**.
Comment: One question is how much you want to use the UART, and in which directions.  If you only want to generate an occasional debug or status message, at a time when your processor is not under much additional demand, bit banging serial output can look very attractive.  There are ticks such as using pin-change interrupts which can lessen the average load of having an input channel too, but if you expect to receive characters at a high baud rate at a time when you have other real-time commitments, it may be an issue.
Comment: Just my very subjective $0.02, but I would usually prefer a separate dedicated battery controller and uC-integrated UART instead of the other way around. Why do you need the battery management integrated in the uC?
Comment: I have to use rechargeable batteries which will be getting charged using a solar panel so I need 4 battries in series whch will be used one at a time
Answer: As others have noted, you can either add additional hardware to your system to provide the UART functionality, or you can emulate one in software. If you have control of the overall hardware design and adding another IC is an option, I would strongly consider the hardware-based approach. You can certainly make a software UART work using bit-banging, but you might not want to dedicate the CPU resources to generating the required timing.
From a glance at the datasheet, it appears that your microcontroller has both SPI and I2C (which Atmel calls a Two-Wire Interface (TWI)). These would probably be the best interfaces to use in order to attach an external UART. Said devices are available from a number of manufacturers. Some examples:

Exar (http://www.exar.com/connectivity/uart-and-bridging-solutions/i2c-spi-uarts) has a line of SPI/I2C 1- and 2-channel UART devices available, covering the ~1.6-3.3V operating range. I've not used any of these parts specifically, but I have used Exar devices in the past (with parallel memory-bus interfaces), and they have worked well.
NXP (http://ics.nxp.com/products/bridges/i2c.spi.slave.uart.irda.gpio/) has a line of SPI/I2C UART/IrDA/GPIO devices available, also in 1- and 2-channel varieties over a couple voltage ranges. I have used these parts (specifically the SC16IS762) extensively in the past with great success.
Maxim (http://www.maximintegrated.com/datasheet/index.mvp/id/2052) has the MAX3110E and MAX3111E devices, which are SPI-connected UARTs. One unique feature of these devices is that they have an integrated RS-232 line driver. So, if you need your UART to interface to a device that uses RS-232 line voltages instead of logic levels (e.g. a PC), this might be useful, as it will save you from adding another line driver IC to your board.
Comment: Wow, never knew Maxim had those items, would +2 if I could.
Answer: If you are looking for a hardware solution, Maxim has several UART ICs with an SPI interface to the microcontroller (which is included in your part). Look at MAX3100 or the other options here: http://www.maximintegrated.com/products/interface/controllers-expanders/uart.cfm
Answer: You will need to use a software UART driver. Depending on exactly what you expect from this UART, you could use AVR305 (extremely compact, but no features beyond blocking half-duplex send/receive), AVR274 (interrupt driven, fairly feature complete), you could write your own software UART driver or you can use one you find on the internet, for instance by googling 'avr software uart'
Answer: A brief note about software "UART" design: there are at least qualitatively different approaches one may take, depending upon requirements:

A "take over everything" bit-bang driver will disable all interrupts and use cycle-counted code to clock each bit.  Receiving data with a "take over everything" driver requires that when data arrives the controller is doing nothing but waiting for it.
A "take over main loop" bit-bang driver will behave much like the above except that it will use a timer resource for bit timings rather than cycle counting.  Interrupts which do not take too long to service may be left enabled.  For serial transmission, the fixed-rate timer resource may be shared with other purposes; for serial reception, however, the bit-bang driver will have to be able to reload the timer when the start bit arrives so as to make it expire in the middle of each incoming bit time.
A fully-interrupt-driven bit-bang driver uses a fixed-rate timer that's running at some multiple of the data rate preferably (3x and 5x are both better than 4x), and does everything through that timer.  Such a driver can run simultaneous with everything else, but will require a faster CPU than the former driver types would require.

To avoid having the first two styles of controller wait forever for data that may never come, it's common for read routines to include a timeout value.  Note that if a a controller's loop does e.g. "get a byte while waiting up to 100ms for it, do some other stuff if none came, then get the next byte, etc." and a byte arrives between the time the "get" routine times out and the controller starts waiting again, that byte will be lost; the device it's communicating with will have to expect that possibility.
Only the third style of driver will be able to handle the possibility of a data byte starting to arrive while a data byte is being transmitted.  The first two styles can, however, be used for some full speed full-duplex communication protocols if the controller only has to speak when spoken to.  The trick is to have a "read and write data" routine which will wait for an incoming start bit, and when one is detected overlap a read and write such that the controller sends each bit just as it's about to examine the incoming data.  Once the controller detects the incoming start bit, it will know exactly when it will should look for next 8 data bits and stop bit, and will thus know that it can safely use the time between to output its own data.
One parting note: a controller that uses one of the first two styles of bit-bang uart to receive data must process each byte of data before the falling edge of the next byte's start bit to avoid data loss.  If the controller knows that processing will take at least half a bit time, it may maximimize the time available for processing by accepting each byte as soon as it has grabbed the last data bit, rather than waiting for the stop bit.  As a further means of giving the controller more time, however, it may be helpful to have the device that's giving it data transmit with two stop bits rather than one.  If "mark parity" can be configured, that will add another extra bit time.  Transmission at e.g. 115200-8-M-2 will allow more processing time than 57600-8-N-1, even though it will feed data more than 1.6 times as fast.
Answer: You can simply use the I/O pin of  the uC. Only thing when switch or transfer data on these pins you should have frequency of the pins double to the baud rate. This is how UART normally works, it will sample the bit signal  at the middle.


How do you say 1/1024th

Question: Is there such a fraction in English as: "1/1024th" and if so, how is it pronounced? I can't image we say: "One thousand and twenty fourth" Maybe the correct way is to write it without the "th" and say something like: "a probability of one divided by one thousand and twenty four".
Comment: As a *fraction*, I can't imagine anything other than "one one-thousand-and-twenty-fourth", because that is how fractions are read. As a probability (or proportion), I would say "one in one thousand and twenty four".
Comment: I would say "one [pause] thousand and twenty fourth" or "a thousand and twenty fourth". I'm from Southern England.
Comment: Side note: I might hear "one ten-twenty-fourth" as a shorthand, a habit perhaps traced to reading clock time or years, where we don't say "two thousand nineteen" but "twenty-nineteen."
Comment: A probability would be more likely to be expressed as a percentage, I think — even approximately, like 0.1%. Fractions are standard ordinals (except for half and quarter, and even there "fourth" is not unheard of).
Comment: I would say *"one one-thousand-and-twenty-fourth."* I'm Canadian.
Answer: Notice there's a general difference between BrE and AmE in speaking numbers, specifically with saying the word "and":

In American English, many students are taught not to use the word and anywhere in the whole part of a number, so it is not used before the tens and ones. It is instead used as a verbal delimiter when dealing with compound numbers. Thus, instead of "three hundred and seventy-three," "three hundred seventy-three" would be said. Despite this rule, some Americans use the and in reading numbers containing tens and ones as an alternative variant.
  English numerals

You can also see some comparisons at mathisfun.com

US
  1,101 one thousand, one hundred one
  UK
  one thousand, one hundred and one
  US
  15,016 fifteen thousand, sixteen
  UK
  fifteen thousand, and sixteen
  (No hundreds? Don't write them! but the and is still needed in the UK)

It should really say BrE instead of UK, because the "and" is used more widely across the world than just the UK.
When reading a fraction the first number (numerator) is stated as a cardinal number, one, two, twenty-seven.
The second number (denominator) can be stated as either a cardinal number or an ordinal number. Here are a number of alternatives (don't forget the "and" difference between BrE and AmE generally)
1/1024 or 1/1024th (assuming this notation even makes sense, which I'm not sure it does) can be said (and this is not exhaustive):

One one thousand and twenty fourth - ordinal
One in one thousand and twenty four - cardinal
One part in one thousand and twenty four - cardinal
One over one thousand and twenty four - cardinal

If you are talking probability you'll probably want to go for the second one.

The probability of that is one in one thousand and twenty four

You can also say:

That has a one one thousand and twenty fourth chance of happening

just as you'd say:

That has a one twelfth chance of happening.

However I think the "[cardinal] in [cardinal]" construction would be more ideal and clear.
Statements where very large numbers are stated as ordinals can be unnecessarily more difficult to say.

128/5,353,958

One hundred and twenty-eight (five million three hundred and fifty three thousand, nine hundred and fifty eighths).
Again, don't forget the "and" difference, and notice the:

-th suffix
  Used to form ordinal numbers: millionth.
American Heritage Dictionary

Only appears on the last number.
Answer: I believe that the way you would approach the pronunciation of such a fraction would depend on the context in which it was being used.
If used purely as a fraction in a Mathematical context, "one one-thousand-and-twenty-fourth" would be appropriate. Unfortunately, the denominator is rather long and the expression may sound confusing.
So I would suggest you express the fraction like so:

one over one-thousand-and-twenty-four

With the "over" indicating that division is the mode of mathematical operation being used.
Alternatively, if the fraction was being used as odds in the context of Probability, you could express it as:

one in one-thousand-and-twenty-four

or as a percentage:

0.0977% (rounded to 3 significant figures)

If expressing an exact value is not necessary, you could round the denominator to a thousand. Thus becoming:

approximately one one-thousandth
Comment: @David Toh Thanks for your answer. Is it consistent for both N. American and European English?
Comment: @Baz As in English and American English? I do believe it is consistent.
Answer: Using "one part in" is often useful to avoid ambiguity. Here you could say "one part in a thousand and twenty four" (British - Americans would drop the "and").
In this specific case it may actually be more instructive to say "one part in two to the ten" (or even "... power of ten") as you've almost certainly got to this fraction from a 10-bit value of some sort. You could also use "one over two to the ten" (or "one over one oh two four").

How do you say 1/1024th


How to calculate main aspect of a glacier?

Question: Aspect is based upon the direction of flowline axis of the glacier. is flowline axis same as ice flow direction?
What is aspect of a mountain (say in the tropics).
Would a glacier have aspect different from the aspect of the mountain underlying the glacier?
Answer: Aspect refers to the direction in which a surface is directed. A mountain will have different aspects depending on which slope you consieder so your notion that a mountain has a single aspect is not correct. Therefore a mountain slope in the tropics would still have aspects to the north, south, east, west and so on.
As for calculating the aspect of a glacier it can be a little complex. Smaller glaciers occupying a cirque or a valley will be simple to evaluate since it will be direction of the slope of the glacier, valley direction for a valley glacier. That said, it is not uncommon for a valley glacier to have several contributing cirques or side valley which by themselves will have different aspect from the main part of the glacier.
When considering larger valley glaciers the valleys in which they reside can have varying directions along the glacier length so that the aspect fo the glacier varies along its length. The extreme case will be an ice cap which like a solitary mountain will have aspects varying 360 deg depending on which part of the ice cap you study. Oftan ice caps are divided into separate catechments and this aspect is given for each of the catchment rather than the ice cap as a whole.
So aspect of a glacier will reflect the general flow direction of the glacier, reflecting the topography in which it is located, but it can be a very difficult parameter to evaluate for some cases.
Comment: Thank you, I was confused on how to guess the aspect of glacier by myself instead of relying on the 'aspect' function in arcgis.


How can I configure nano to save every 10 seconds?

Question: I need to have my nano editor autosave every 10 seconds or some specific time period. How can I achieve this ?
Answer: There is no way to make nano to autosave the file that you are editing at a specific time period. You can save a file everytime when you want without exiting from nano with Ctrl+O("O" from "Omega", not zero) or F3.
But, don't worry, automatically saves backups. See https://manual.cs50.net/nano/#__save_files:

If you have been using nano, you may see files with the ".save"
  extension appearing in directories in which you are working. If you
  are editing a file (let's call it "hello.c") on a server and somehow
  your connection to the server is lost, whether because you closed the
  terminal window or you lost your connection to the internet or some
  other unknown reason, nano will automatically save a backup of
  the state of the file in a new file with a ".save" extension (e.g.
  "hello.c.save"). So, when you log back onto server, don't worry that
  you've lost everything you've been working on because you hadn't saved
  for an extended period of time, you can simply open up the ".save"
  file and then continue from where you left off, and when you go to
  save the file, you can save it with the name of the original file
  (without the ".save" extension). Don't rely entirely on this though,
  such as thinking you can just close your terminal window without
  saving because nano has got you covered, because in a very few cases
  the file is not correctly created.
If a ".save" file already exists and you open up the file without
  the ".save" extension, and your connection is lost again, nano
  will save the file with a ".save.1" extension, incrementing the
  number at the end of the extension for each time. If you have open a
  file without a name and lose your connection, the file will
  automatically be saved with the name "nano.save".

That being said, I do not see any reason of concern for autosaving files in nano.
Comment: Source: https://manual.cs50.net/nano
Comment: Wow. That's pretty blatant plagiarism.


UNIT_SPELLCAST_START event, spell names, localization issues?

Question: I have created a small addon for myself, SheepWhisperer which listens for me casting Polymorph on my mage or Shackle Undead on my priest.
When it detects this, and I'm in a party, it will check if I'm targetting a mob that one of the other party members are also targetting. If so then it will send them a whisper telling them about my incoming spell.
So far the addon works for me, but I'd like to publish this addon for others to use.
The event gets called with the spell names, not the spell id's, which means that my code currently looks for the following two spells by their names:

Polymorph
Shackle Undead

The question is this: If someone is running the German client (or any of the other clients, other than the English one), will they get different names or will this event still be called with "Polymorph"?
I have checked Wowhead: Polymorph but it doesn't tell me the German (as an example) name for that spell. Perhaps there is none? Perhaps all the clients use Polymorph so this is a non-starter?
Answer: The answer is yes, this will be a problem.
I found files from many addons that contains localized spell names, here's one such example - https://github.com/laytya/Libs2/blob/master/Babble/Babble-Spell-2.3/Babble-Spell-2.3.lua
Example:
<code>...
["Shackle Undead"] = "Сковывание нежити",
...
["Shackle Undead"] = "Untote fesseln",
...
</code>
so yes, this has to be solved.


how can I transfer nokia lumia 8 data to samsung galaxy 3

Question: how can I transfer nokia lumia 8 data to samsung galaxy 3
I tried Transgo the usb cables would not connect to the PC even after I bought good quality cables.
Comment: What data specifically do you expect to transfer from Lumia to Samsung?
Answer: You can Use this app to share your contacts.
http://www.windowsphone.com/en-in/store/app/qontact/e3404be4-324f-46e3-b47d-5561c676cad6
You Can Also Sync your Contacts between Lumia 820 & Galaxy S4 using your Hotmail ID. Just login your Hotmail ID to your galaxy S4 and Sync.
You Can Export Your Contact from https://people.live.com using your hotmail id in *.csv format then import in your Phone or Google Account Which you are using in Galaxy S4.
From Microsoft Answers
Comment: Android Contacts has no support for .csv format. Instead .vcf files are imported into the contacts list. So if there is an option to export vcf format please update you question. Else suggest another option for importing the data. Also please explain on "How to" part of importing/exporting the contacts.
Answer: Follow the instructions:

Download an app which can make a backup of your Contacts in a <code>.vcf</code> file.
Copy this file and paste it into your Android phone storage.
Click this file from your Android phone. It will automatically export the contacts to your contact list.

Alternatively, download SHAREit app in both phones. Then send your contacts from one phone to another.
Comment: No. Android won't automatically import .vcf files when opened. You need to import them in your Contacts app manually by selecting Import option. And OP asks for data transfer and not specifically just for contact. So this only partly answers the question.
Comment: its not necessary  or it depends on android version . in kitkat & upper it will automatically restore your contacts when you click on it.


APCA (WCAG 3.0) does not allow for 14px font to be used as a regular base

Question: According to APCA (WCAG 3.0), we are not able to use 14px font as a regular base, but when it comes to SaaS application design, 14px is commonly used as the base font size. Despite my attempt to use pure black as a color, I was still advised to avoid it. This raises the question: how can we make the base font more accessible without increasing the font size?
Comment: WCAG 3.0 is still a long time - probably years - away from being the accepted standard. As of Feb 2023 WCAG 2.2 still hasn't been officially signed-off. You can use WCAG 3.0 as reference, but it's probably 2.2 you should be using today. There is no specific font-size requirement, and it's also going to depend on the device it's on (i.e. a phone is closer to your eyes than a laptop, so can have smaller text)
Comment: Hi @JonW  Holding a phone closer to the eyes doesn't work so well for people with presbyopia, which is pretty much everybody over the age of 42 or so. More importantly, not everybody has nice retina displays. Standard resolution displays don't do particularly well with fonts smaller than 14px, anti-aliasing effects tend to mangle tiny thin fonts and blend them into the background, reducing contrast substantially. Something we are considering is using media queries to determine screen resolution, which would allow alternate layouts based on screen technology.
Comment: Hi @JonW ... Yes you can hold the phone closer to your eyes and manufacturers know this as well, so the pixel pitch is much denser on the phone then on a desktop display for example. What's important is visual angle, and the CSS reference px is based around a visual angle of 1.278 minutes of arc as subtended onto the retina... So yes, you view your phone much closer, but those pixels are also much smaller. [See this chart](https://user-images.githubusercontent.com/42009457/136944120-d8635a12-2240-413b-98a2-995e216a6a82.png)
Answer: Short Answer
It actually depends more on the x-height, and on the use case as well. What was in the FPWD of WCAG 3 (over two years ago) was little more than a placeholder.
Longer Answer
DISCLOSURE: I created the APCA, and am research lead regarding the continued development of the related guidelines that emerged from the Visual Contrast group under Silver/WCAG_3.
This is still a project under active research and development. What is currently active is a public beta, and questions and comments are welcomed at the readability forum at the GitHub repo.
Here's a relevant example:
14px Verdana has the same x-height as 17px Times New Roman.
So, it's not 14px for any particular font, it's 14px for a reference font, and other fonts need to be matched to that, in theory. Bronze level won't require this, but higher levels of compliance will.
And at this time, CSS does not have a reasonable nor well adopted way to set x-height directly. And that's still not the whole battle. Font weight is also non standard, and we haven't even broached the subject of glyph design.
Visual contrast is directly affected by spatial frequency, for our purposes that means font weight and font size. Above about 28px bold (depending on the font of course) we're getting into the "contrast constancy" range, where increases in contrast have little to no functional effect.
However for fonts smaller/thinner than that we very rapidly lose contrast sensitivity and therefore have to substantially increase luminance contrast to maintain readability.

A 14px font is considered equivalent to a 10.5pt font in print, other factors being equal. Is it big enough?
That depends on how readable you want it to be.
Something that we are introducing to the guidelines right now is "use cases" where are the purpose of the text dictates how readable it needs to be. For instance, you don't need a copyright notice to be at the best and most readable contrast in fact that would only cost clutter in the design.
I discussed use cases in this thread which is draft material that's being worked into an actual guideline at the moment.
x-height marks the spot
The other thing that is particularly important is the x-height, more-so than the font-size: ... For standard vision, the critical x-height for best fluent readability is a visual angle of at least 0.2° as subtended onto the retina.
0.2° is 12 minutes of arc.
Theoretically, the CSS reference px is 1.278 minutes of arc, which assumes a reference display at a given distance. Manufacturers set the pixel pitch on their devices based on viewing distance, and 1.278 minutes of arc per px is not unreasonable.
What this translates to is an x-height of a little less than 9.5px, this is for standard 20/20 vision for best speed and comprehension, when associated with an appropriate (i.e. critical) contrast.

For Verdana, this is font-size: 17px
For Times, this is font-size: 21px

Your mileage may vary.
Public Beta
While WCAG 3 is years away, there is a pressing need today for perceptually uniform contrast guidance, in particular for use with Dark Mode, as WCAG 2.x can not calculate dark colors correctly.
The APCA Readability Guidelines are a public beta, and better for actual accessibility. For instance, APCA is better at helping color vision deficiencies such as protanopia, and for determining contrasts for dark mode.
Pure Black
The use of pure-black for body text is absolutely fine, in fact for body text it's usually ideal. The actual problem with "too much contrast" is related to too high of a screen luminance.
I also discuss this in the overview article "The Realities And Myths Of Contrast And Color".
Please feel free to follow up with questions.
References

whats-red-black-also-not-read
please-stop-using-grey-text
realities-myths-contrast-color
APCA Draft Test Methods
Answer: It's more nuanced than that.
WCAG 3 uses a rating and three levels of compliance. So you are able to use any font size you want, but it will impact your rating accordingly.

Rating 0: Any failures on the Advanced Perceptual Contrast Algorithm (APCA) lookup table or the lowest APCA value is more than 15% below the values on the APCA lookup table
Rating 1: The lowest APCA value is 10-15% below the values on the APCA lookup table
Rating 2: The lowest APCA value is 5-9% below the values on the APCA lookup table
Rating 3: The lowest APCA value is 1-4% below the values on the APCA lookup table
Rating 4: All reading text meets or exceeds the values on the APCA lookup table

WCAG 3 Guideline Visual contrast of text
The APCA Contrast Calculator returns a Lightness Contrast (Lc) of 106 for white on black.
The algorithm also takes into account the font weight. So 106 will achieve the highest rating for:

14.5px at 400 (normal)
14px at 500

You can increase font-weight to improve the accessibility score.
Comment: Hi @Andy ... just an FYI, that rating system is no longer part of WCAG3, WCAG3 is undergoing a major overhaul at the moment, expected to take several more years. That said, font weight is definitely a huge predictor of contrast on displays because increasing weight lowers the spatial frequency which improves contrast.


Batch remove invisible characters from filenames

Question: I have hundreds of files on external drive that were probably copied a lot, and likely recovered at some time too. The filenames seem tho have acquired some weird characters over their lifespan and I need to fix them.
The problem is that I can list them with ls, but I can't do anything to them by referring to their names.
ls -l renders this result:
-rwx------  1 krzysztof  staff  322451 Jun 27  2009 file015.jpg
-rwx------  1 krzysztof  staff  331337 Jun 27  2009 file016.jpg
-rwx------  1 krzysztof  staff  303078 Jun 27  2009 file017.jpg
-rwx------  1 krzysztof  staff  312346 Jun 27  2009 file018.jpg

The files themselves are not corrupted, and if I manually change the name, the problem goes away. I can also create a file with seemingly exactly the same name (and both will be displayed at the same time with ls). This lead me to believe that there is something fishy going on with invisible characters, which I confirmed by running find . -name '*[! -~]*' - it returned a list of all problematic files.
I wouldn't care about these names normally, but some applications and tools apparently have problem with them too, and just straight up don't see them or ignore them.
One example would be a detox tool that I first attempted to fix the names with - it just pretended they don't exist.
exiftool throws No such file or directory. Similarly, piping the ls -1 to a loop, or saving the file names to a file and then piping them always results in various forms No such file or directory. Like if the invisible characters were not preserved when piping or saving?
$ while read p; do
  mv "$p" "$p"
done <`find . -name '*.jpg'`
zsh: no such file or directory: ./file015.jpg

Is there any way to clean the filenames in batch?
EDIT 1:
Per @terdon request I tried ls -v and ls -B - nothing shows up.
However, the ls | head -n1 | od -c is more interesting, and led me to a discovery of my own too. Here I owe you an apology, because in my original question I changed the names as I thought it didn't matter, but it does.
With that, here is the actual output, where file 014 was fixed manually, and the rest is broken:
❯ ls -1
Zdjęcie014.jpg
Zdjęcie015.jpg
Zdjęcie016.jpg
Zdjęcie017.jpg
Zdjęcie018.jpg

And here is ls | head -n2 | od -c - I used n2 to show more than first filename.
❯ ls | head -n2 | od -c
0000000    Z   d   j   e    ̨  **   c   i   e   0   1   4   .   j   p   g
0000020   \n   Z   d   j   e    ̨  **   c   i   e   0   1   5   .   j   p
0000040    g  \n
0000042

As you can see there is a ę character in both files, and it seems to be the same in ls | head -n2 | od -c. But! When I went back to edit and rename the files manually, in 014 (fixed file) when I position cursor after ę and hit backspace, the entire character disappears. This is not the case for other files - pressing backspace on ę changes it to e, and only second backspace removes it.
Thank you @terdon - now we know where the problem is. How can this be fixed in batch?
EDIT 2:
014 is fixed, 015 is broken:
❯ ls | head -n2 | LC_ALL=C sed -n l
Zdje\314\250cie014.jpg$
Zdje\314\250cie015.jpg$

EDIT 3:
As suggested in comments, I attempted to apply solution from How to rename filenames with accents on macOS? but again run into the No such file or directory
❯ rename $'s/\u119/e/g' ./*
Can't rename './Zdjęcie015.jpg' to './Zdjecie015.jpg': No such file or directory

rename $'s/\u0328//g' ./* does nothing both in bash and zsh
EDIT 4:
❯ PERL_UNICODE=ASD find . -depth -execdir rename -n 's/\pM//g' {} +
'Zdjęcie015.jpg' would be renamed to 'Zdjecie015.jpg'

and
❯ PERL_UNICODE=ASD find . -depth -execdir rename 's/\pM//g' {} +
Can't rename 'Zdjęcie015.jpg' to 'Zdjecie015.jpg': No such file or directory

Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/139382/discussion-on-question-by-devligue-batch-remove-invisible-characters-from-filena).
Answer: I'm not sure if this really is an answer as I wasn't able to make it work from macOS, but it certainly is a workaround that solved my problem.
Since the external drive was a NAS, I ssh'ed into it and fixed the problem directly. Unfortunately fancy tools like rename were unavailable to me, so I had to craft something using find, mv and sed - and it worked just right!
Here is the command I used:
find ./ -maxdepth 1 -name "*.JPG" -exec sh -c 'mv "$1" "$(echo "$1" | sed s/Zdj.*cie/zdjecie/)"' _ {} \;

P.S. Thanks to the heroes from the comment section for helping along the way!


It is possible to make snap using Google Maps based on QGIS?

Question: Vectorized few lines using QGIS with Google Maps as a base.
If I do not Trabachar with maximum zoom does not respect the topology of the base.
It is possible to make snap using Google Maps based on QGIS?
Answer: No, you cannot snap to Google Maps or any other raster layer. Snapping only works with vector layers.
Answer: You cannot do it with Google maps - if you're after a vector dataset, look into the use of openstreetmap data. It may possibly already include what you need. You can download what you need through the OpenStreetMap plugin.


Can't use --help with printf

Question: Most programs print usage and quit with "--help". But I can't get it to work with printf:
$ printf --help
bash: printf: --: invalid option
printf: usage: printf [-v var] format [arguments]

man 1 printf says:

SYNOPSIS
       printf FORMAT [ARGUMENT]...
       printf OPTION
DESCRIPTION
       Print ARGUMENT(s) according to FORMAT, or execute according to OPTION:
       --help display this help and exit

There's also nothing wrong about the coreutils source code:
  /* We directly parse options, rather than use parse_long_options, in
     order to avoid accepting abbreviations.  */
  if (argc == 2)
    {
      if (STREQ (argv[1], "--help"))
        usage (EXIT_SUCCESS);

      if (STREQ (argv[1], "--version"))
        {
          version_etc (stdout, PROGRAM_NAME, PACKAGE_NAME, Version, AUTHORS,
                       (char *) NULL);
          return EXIT_SUCCESS;
        }
    }

Why can't I do printf --help?
Answer: There's two types of printf. The one provided by coreutils and the one provided by Bash as a shell built-in.
$ type printf
printf is a shell builtin
$ /usr/bin/printf --help
Usage: /usr/bin/printf FORMAT [ARGUMENT]...
  or:  /usr/bin/printf OPTION
Print ARGUMENT(s) according to FORMAT, or execute according to OPTION:
...

In order to get help about Bash's built-in, use the help command instead:
$ help printf
printf: printf [-v var] format [arguments]
    Formats and prints ARGUMENTS under control of the FORMAT.
...

Answer: There are two printfs available to you: the shell builtin and an executable.  The shell builtin is described in man bash.  It does not support --help.  You can, however, get information about it with help printf.
man 1 printf describes /usr/bin/printf and it does, in fact support --help:
$ /usr/bin/printf --help
Usage: /usr/bin/printf FORMAT [ARGUMENT]...
  or:  /usr/bin/printf OPTION
Print ARGUMENT(s) according to FORMAT, or execute according to OPTION:

      --help     display this help and exit
      --version  output version information and exit

FORMAT controls the output as in C printf.  Interpreted sequences are:

  \"      double quote
  \\      backslash
  \a      alert (BEL)
  \b      backspace
  \c      produce no further output
  \e      escape
  \f      form feed
  \n      new line
  \r      carriage return
  \t      horizontal tab
  \v      vertical tab
  \NNN    byte with octal value NNN (1 to 3 digits)
  \xHH    byte with hexadecimal value HH (1 to 2 digits)
  \uHHHH  Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)
  \UHHHHHHHH  Unicode character with hex value HHHHHHHH (8 digits)
  %%      a single %
  %b      ARGUMENT as a string with '\' escapes interpreted,
          except that octal escapes are of the form \0 or \0NNN

and all C format specifications ending with one of diouxXfeEgGcs, with
ARGUMENTs converted to proper type first.  Variable widths are handled.

NOTE: your shell may have its own version of printf, which usually supersedes
the version described here.  Please refer to your shell's documentation
for details about the options it supports.

GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Full documentation at: <http://www.gnu.org/software/coreutils/printf>
or available locally via: info '(coreutils) printf invocation'

Answer: printf is a shell (bash) built-in too. So when you run
printf --help

the built-in printf is executed because by default the built-in ones always get precedence over the external ones and it doesn't have --help option, hence the error.
To find all the available printf executables:
type -a printf

It will show the executables in the order of precedence.
You can check the help page of built-in printf by:
help printf

On the other hand if you want to run the external printf, do any one of the following:
command printf
"printf"
'printf'
\printf

Can't use --help with printf


Is every solution of a nonhomogenous linear recurrence also a solution to some homogenous linear recurrence?

Question: In particular, if I have a nonhomogenous linear recurrence of the form
$$
a_n = c_1a_{n-1}+c_2a_{n-2} + \ldots + c_ka_{n-k}+p(n),
$$
where $p(n)$ is a polynomial, does it follow that every solution to this is also a solution to some non-trivial homogenous linear recurrence?
Answer: Yes, it does, at least for a polynomial $p(n)$. It is basically the idea behind the annihilator method $-$ which is more famous for solving differential equations, but nothing prevents you from adapting it to a discrete context such as recurrence relations.
If $La_n = p(n)$ is your recurrence relation, with $L = 1 - (c_1S + \ldots + c_kS^k)$ for instance in your example, where $S$ is the shift operator (acting as $Sa_n = a_{n-1}$), then it is solved by $a_n = b_n + c_n$, where $b_n$ solves the homogeneous problem and $c_n$ is a particular solution to the nonhomogeneous problem. Next, if $A$ is itself a linear operator such that $Ap(n) = 0$, then $AL$ generates the homogeneous linear recurrence relation you are looking for, because $ALa_n = Ap(n) = 0$.
However does such an annihilator $A$ always exist ? For $p(n)$ a polynomial expression of degree $m$, it takes the form $A = (S-1)^{m+1}$, since it is associated to the characteristic polynomial $(r-1)^{m+1}$. Why so ? Because, more generally, multiple roots of the characteristic polynomial produce polynomial prefactors; indeed, the characteristic polynomial $(r-\lambda)^{m+1}$ corresponds to the solution $a_n = (\alpha_0 + \alpha_1n + \ldots + \alpha_mn^m)\lambda^n$.
Comment: Thank you. I can see that it works, and I think I to an extent understand why it does, but I'm having a bit of a hard time seeing why exactly the annihilator takes the form $(S-1)^{m+1}$.


How to restore the previous one workflow in sharepoint designer 2013 ?

Question: I have made some changes on my workflow i want to rollback to old one how can i do?
I search it but in 2013 designer under All files -workflows i can't see the workflow.
Answer:
A Sharepoint designer workflow? To re-activate an old one, go to the
  list, settings, workflow settings, you should see the different
  versions.  Click (strangely enough) Remove a workflow...re-active the
  old version.
Or, for the source files from sharepoint designer navigate to
  workflows, find yours, expand it until you find the .aspx and .xml
  files.  Right-click and choose version history.
Visual studio doesn't do versioning.

Source
Refer also this


Direct access to DGPS data in QGIS?

Question: I'm heading out to the Arctic Circle (Spitsbergen) I have a Sokkia DGPS and Magnet on a tablet device (connects to the DGPS and logs the data), they connect via blue tooth etc. Can I bring the data straight into QGIS bypassing Magnet?
Comment: You might want to check that your DGPS performs the way you expect at the destination. Considerations would be DGPS correction reception, correction accuracy (reasonable ground station locations) and satellite geometry (GDOP), especially if you don't have good visibility to the south.
Answer: If the data logger stores the positions as tabulated file with Longitudes and Latitudes you can visualize that and, I think you can tell QGIS to watch the file for any alterations.
So basically, yes
Comment: I believe you are looking for a NMEA ouput directly from the GNSS sensor to consume in in the QGIS software. This could be an option on the GNSS receiver, but I believe Magnet would still be needed to initially configure the GNSS receiver for DGPS corrections and establish the NMEA output (message types, which port is being utilize to send the data, etc.). You would be best served to contact your local dealer for additional help.

Direct access to DGPS data in QGIS?


Is there a way to detect if a website is using SPDY?

Question: Is there a way to detect if a website is communicating with Chrome using SPDY?
Comment: You can use http://spdycheck.org to check SPDY support.
Answer: You can view your active SPDY sessions in a current build of Chrome by pulling up:
<code>chrome://net-internals/#spdy
</code>
Comment: Is there something similar to this for Firefox (without using an extension)?
Answer: Mike Belshe said

Yes, indeed SPDY is enabled in Chrome
  and on Google servers for all SSL
  traffic at this point.  (Actually, we
  do 90% on SPDY, with a 10% holdback
  for purposes of A/B comparisons).

http://groups.google.com/group/spdy-dev/browse_thread/thread/4c2396ecbc36b1c4
Answer: chrome://net-internals/#spdy to see active SPDY sessions

Google services run over SPDY (search, gmail, etc)
F5 announced SPDY support on their appliances at Interop 2012
Akamai announced technical preview for SPDY at Velocity 2012 (June 2012)
Cloudflare announced SPDY beta for their customers (June 2012)
As of early March 2012, twitter.com is running SPDY
There are a few specialized CDN's which have SPDY enabled
Nginx supports SPDY (draft 2)
Apache has a great mod_spdy module
Comment: Opera Turbo uses SPDY as well.
Answer: On a couple of SPDY sites I checked, there appear to be these additional request headers that don't appear on standard HTTPS requests.  That might indicate the use of SPDY without requiring a browser extension.
<code>:host:     yump.com.au
:method:   GET
:path:     /
:scheme:   https
:version:  HTTP/1.1
</code>

You'll also notice that all the request and response header variables are in lowercase (is that part of the SPDY protocol?).
Comment: You are ABSOLUTELY right. The spdy protocol draft 3.1 (link below) even talks about this in section 5.2.

Thx for noticing this. I was going crazy trying figure this out. I need to do this because i want to use a performance testing tool (such as jmeter or loadrunner) instead of a browser to access a SPDY enabled server.

https://sites.google.com/a/chromium.org/dev/spdy/spdy-protocol/spdy-protocol-draft3-1
Answer: 46.5% of browser traffic now supports SPDY (see http://caniuse.com/spdy ), so almost half the users that hit google, twitter or other SPDY enabled websites are already using SPDY.
If you want to get similar gains for your website, then use jetty (7, 8, and 9 all have SPDY support).
Answer: Chrome has a plugin to show you which sites are SPDY enabled.
http://www.devthought.com/2012/03/10/chrome-spdy-indicator/
Comment: There is a similar plugin for firefox too: https://addons.mozilla.org/en-us/firefox/addon/spdy-indicator/
Answer: Jetty Servlet engine also got decent spdy support. It's completely transparent for the web developer and just needs to be enabled on the server config:
http://wiki.eclipse.org/Jetty/Feature/SPDY
Answer:
The website http://spdycheck.org/ checks if SPDY is enabled on a website.
The Google Chrome extension will tell you with a green icon in the url bar. (https://chrome.google.com/webstore/detail/spdy-indicator/mpbpobfflnpcgagjijhmgnchggcjblin?hl=en)
There is also website https://isspdyenabled.com/ to tell you if your browser is supporting SPDY
You can use Chrome Flags to see more details information visit chrome://net-internals/#spdy in chrome

SPDY is enabled by lots of the major websites: Google, Twitter, Facebook etc
With IE11 supporting SPDY the future looks SPDY... :-D
Answer: From the major sites, SPDY is served on all Google products, Twitter, Wordpress.com, TechCrunch.
Answer: Amazon Kindle Fire may be using SPDY for HTTP traffic through their Silk proxy.  This is based on Amazon's public job posting: http://aws.amazon.com/amazonsilk-jobs/ and is not verified or confirmed elsewhere.
Answer: You can enable network.http.spdy.enabled in Firefox 11's about:config and add this extension:
https://addons.mozilla.org/en-US/firefox/addon/spdy-indicator/
Answer: Try WAPPALYZER,
They provide addon for both Mozilla & chrome browser.
It can identify everything about any website like, server technology, server scripting language, client side scripting language, site using plugins & all major things from most of the websites.
https://wappalyzer.com/download
Answer: I doubt that it's used, as the current Chrome/Chromium only supports SPDY detection using the SSL NPN extension, which was only recently added to the edge openssl. And the Alternate-Protocol which is not npn is not supported.
http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft2#TOC-Server-Advertisement-of-SPDY-throug
Update: While this answer was correct in 2010, when it was written, in 2014 it's quite a different story.
Answer: Just sniff the TCP/IP packagees from and to the webserver, and check where they are SPDY packages or just HTTP.
Comment: As Google is author of SPDY and Chrome was first browser implementing SPDY on client I have to down vote your answer.
Comment: This is a 4 year old answer. I'll update it. But I'm not sure if downvoting is the right way to make the answer's author update it.