3DBenchy's bow prints out of alignment

Question: I'm new to 3D printing, but I've solved all of my problems except for this rough surface shown in the image of a Benchy  print:

Any suggestions are appreciated.

Printer (new): Raptor 2 (400x400x700 mm)
Bed Temp: 65 °C
Extruder Temp: 210 °C
Filament: PLA (1.75 mm) right out of the package (came with printer from
Formbot)
200 degrees extruder; 60-degree hotbed - print success, bow issue
persists. speed: 100
fade height: 0
nozzle: 200
bed: 60
fan speed: 255
flow: 100 probe offset: -1.4
Comment: Possible duplicate of [Calibration improvement of the prusa I3](https://3dprinting.stackexchange.com/questions/7671/calibration-improvement-of-the-prusa-i3)
Comment: Hi Harrison, welcome to 3D Printing.SE!
Comment: Too much temperature, try at 195 °C.
Comment: You should also specify print speed (see my answer) and layer height.
Comment: Best results so far: 200°, 60° hotbed, 50 speed. Best yet settings still need to be tweaked. Not sure where to go?
Comment: sadly the new pictures are barely visible. More light is needed, and an indicator which benchy you mean. is the white the one before and the black the new one? it would be better to have both in the same color.
Answer: You print too hot and probably with not enough cooling. These typical defects are caused by too much heat input into your model. You see this best at the overhang of the bow of Benchy, it should be smooth like the bottom part of the side of your Benchy. It clearly shows heat induced defects. Lower the temperature at least 10 °C. Know that PLA usually is printable at about 190 °C, also 65 °C for the hotbed is quite high, Depending on the surface you could aim for a temperature between 50 - 60 °C,
Comment: At 190°, the print was terrible. Pictured below was printed at 200°, 60° hotbed, 50 speed. Best yet settings still need to be tweaked.
Answer: Turns out the blower on the extruder was not plugged in at the factory. Now it's printing fine. Thank you all for the help and support.
Comment: totally missed that the fan could be off! but the temp drop surely did increase the print quality on its own already.
Comment: As I said I'm my answer: `with not enough cooling.`! Good that you found the plug! :)
Answer: The artifact your bow clearly shows is usually a result of very high print temperature - the filament sags unevenly as it is not cooling to solidification fast enough.
You might want to reduce your print temperature for PLA a little. Try one or two 5° steps. I print my PLA usually at 200 °C, some blends even lower. Do the same for the print bed - 60 °C is the usual temperature in many machines.
When I unpack 210 °C that's only in conjunction with 100 % infill and deliberate over-extrusion for what would be best described as a "cast-solid" result. It's because under that condition I want the filament to melt and merge with everything super tight.
It also might help to change the print cooling geometry to better cool the printed parts - and check if all fans are on.
Answer: If you printed Benchy upright, this is an overhang. You didn't state the print speed that you used, but I found that I can improve overhang quality considerably by printing them slower.
If you're otherwise satisfied with the print quality, you probably don't want to waste time by printing the whole model slower. If you're using Ultimaker Cura there is a setting in the Experimental section (don't worry, it works fine) to print only overhangs slower:

(Those are very conservative settings, a larger angle, like 30°, would probably be fine, too.)
Comment: My speed was 100. Reduced to 50 for most successful print see pic below.
Answer: Try to re-compile the gcode, sometimes the slicer "freaks out" whilst writing the file. Which slicer are you using? (Cura, Slic3r, Repetier, etc.)
I sometimes have that errors, and giving that they do seem quite consistent in shape in the pics I would say that's the issue.

3DBenchy's bow prints out of alignment


What is the answer? Amount or Quantity or Number

Question:
Try to reduce the .......... of cups of tea you drink a day
(amount - Quantity - Number)
Some help please
Comment: In general, if you have "of cups" in there then a count is implied and "number" is most appropriate.  Drop "of cups" and "amount" or "quantity" would be more appropriate.
Comment: The latter two are both acceptable usages. You could say "Try to reduce the amount of tea you drink a day" as well, as "tea" is not countable.
Comment: From now on I am asking every question, here and _i.r.l._, as simply _What is the answer?_
Answer: I don't know if you want the American answer, but an amount is always preceded by a currency symbol, such as a dollar sign.  A quantity is followed by a unit of measure, such as a gallon.  For the people who make coffeemakers, 1 cup equals 4 ounces.  For British tea drinkers, probably not.
Comment: "Amount " can certainly be used for non-currency things - the amount of evidence, the amount of gasoline.
Comment: American dictionaries disagree with this answer.


Working in the space industry with a Physics degree

Question: What roles could a Physics major be employed in within the space industry? Systems Engineer or Technician? How rigorously do space companies adhere to engineering degree requirements in the job description?
Comment: Dr. Wernher vin Braun studied physics before his career in space engineering.
Comment: In my experience, when employers want an engineer they'll hire an engineer. And engineers get training that aren't emphasized in physics, like the design and documentation process, for one. But employers are also more comfortable going with what they know. They might hire the guy with the 2 year electronics degree over the PhD in physics because with the technical degree they know what they're getting. But that may vary for individual employers and applicants, so I don't really know.
Answer: There are lots of jobs in the space industry done by physicists.
Find a project that has a science component and they might need a person with a degree in Physics. They also use people with degrees in Biology, and Chemistry.
Some experiments don't even enter orbit. They are launched from sounding rockets, and capture the data in a short duration flight. Others are launched to orbit planets, or search for planets around other stars. Some orbit the sun, or conduct flybys of other orbiting bodies. Some land on things other than Earth.
If space weather is a concern, then they might need a physicist. Physicists also deal with plasma. You might need a physicist when working on battery technology.
They aren't engineers. They are scientists.
Answer: Dare I write, if you wanted to become an engineer maybe you should have studied engineering.
It may be interpreted as a harsh statement, but you've chosen a more difficult route to achieve a goal.
There is much discussion about diversity in society and the workplace. Hiring people who only have engineering qualifications has a danger of entrenching a mono culture within engineering fields. Having someone with a physics education as an engineer can introduce a skill set which "conventional" engineers do not have.
In the US engineers tend to get a Bachelor of Science as their first degree. It seems to be the accepted path - it's what US colleges tend to offer. Elsewhere in the world engineers get a Bachelor or Engineering degree. It might be a recognition that engineering is more than just science, because it includes amongst other things: economics, accounting, management, human perception and interaction. Apart from being problem solvers, engineers generally design things people will use and interact with, hence human perception and interaction.
It just so happens, yesterday I can across this news item about a person who finally got a Ph. D in Physics at the age of 89. Having had an interest in physics when he was young, in the 1940s, being a European emigre in the US he was advised by family to enter the medical field because of the employment opportunities it presented, as opposed to physics; which is what he did.
The small number of physicists I worked with were not hired to be physicists and had become retrained/re-educated in other fields of science to be employed.
Industry doesn't treat physicists well, possibly because industry doesn't really know what physicists have to offer, academia might have a better treatment. Unfortunately, these days people have to be able to hit the ground running and be immediately useful to their employers. Previously there used to be a period of grace, were a person was permitted to find their feet within the organization and eventually become useful.
To work in the space industry, you may have to sideline your physics qualification and do a bridging course in engineering, something like a graduate diploma, if they such things are still offered.
Comment: Not all industries are the same in this respect. In the case of the semiconductor *manufacturing* industry folks with degrees in Chemistry, Physics and Electrical Engineering work side-by-side; the Ph.D. simply demonstrates that you can learn and do, once one is on the job there is so much more that one must learn that isn't taught in universities what's really important is to maintain a high first derivative.
Comment: ...Applied Physics, Material Science, Industrial Engineering...
Answer: Fred's answer is great and clearly written by someone well-acquainted with the hiring situation in space. I have no real-world experience applying for work in this sector.
At the same time, I wonder if

To work in the space industry, you may have to sideline your physics qualification and do a bridging course in engineering, something like a graduate diploma, if they such things are still offered.

might be slightly pessimistic.
For instance, ESA has a document specifically regarding all the different positions that physicists can find in the space sector.
A spot-check of various jobs at SpaceX shows that physicists are explicitly invited to apply to many 'engineering' positions, particularly those that involve a specific, advanced field of expertise (like optical networking).
Beyond spacecraft and launcher companies, there are countless space sub-specializations that physicists are well qualified for, like remote sensing  - although pursuing these might require a PhD.

It is true that, from a cursory glance, most of the superior positions associated with specific spacecraft, (e.g. Ingenuity) are filled by people with engineering degrees. A famous exception is Randall Monroe, who started work at Langley Research with a physics degree.
The same appears to be true of most of the high-profile tech-transfer technologists into SpaceX (e.g. PICA-X [Dan Rasky], g-fold[Lars Blackmore]); most seem to be engineers. On the other hand, the majority of behind-the-scenes workers on those technologies, at Ames and corporations, appear to be research physicists.


If Sara Conner was Killed?

Question: In 1984's Terminator, the titular character comes from the future to kill Sarah Conner before she could give birth to John Conner.  My question is what would happen if the Terminator managed to kill Sarah before giving birth to John?
Comment: Dupe of; [What is the point of sending anything back in time in the Terminator movies?](http://scifi.stackexchange.com/questions/97261/what-is-the-point-of-sending-anything-back-in-time-in-the-terminator-movies/128827#128827)
Comment: Arnold's account balances would be much, much lower.
Comment: There would be no more movies? This is very speculative question.
Comment: Semi-dupe of [Why is Skynet so obsessed with John Connor?](http://scifi.stackexchange.com/questions/99512/why-is-skynet-so-obsessed-with-john-connor)
Comment: Speculative? yes, but there's only two options.
Answer: The answer depends on how you view time travel in the Terminator universe.
One Timeline
By itself, the first movie presents a situation where there is only one timeline that can't be altered. It's not a paradox that John's father was sent back in time by John, because there was never a timeline where that didn't happen. Kyle Reese was always sent back.
If you take this view, then the Terminator couldn't have killed Sarah, because that's not what happened. If he had, then John wouldn't have been born, so Kyle wouldn't have been sent back, so John wouldn't have been born, so Kyle wouldn't have been sent back, so... MALFUNCTION.
Alterable Timeline
Later movies and series make it clear that one can change the future by going to the past and creating a new, alternate timeline. Viewed this way, the first John Conner that sent back Kyle had a different father. He couldn't have had Kyle as his father, because he hadn't been sent back yet.
In this case, the terminator could have succeeded in his mission, killing Sarah. This would have meant no John Conner in the new future. Skynet's hope was that there would be no new leader to replace him, so that the machines would win the war. There's no way to know if this would have worked out, or if the pressures of history would have found someone new to lead the resistance.

If Sara Conner was Killed?


Magento search not returning results for search words men and women, but returns result for male female

Question: If I write men or women in the search bar, no items are returned in the search result. However, if I write male or female, then the search returns the items correctly. Is there any way to make Magento return those items for those search words?
Comment: are the words "men" and "women" actually in any of your products descriptions etc. Have you tried re-indexing? You can also manually add search terms under Catalog -> Search Terms
Comment: Worked when I put in search terms. If you want put an answer so I can accept. :D
Comment: The Magento LIKE search cannot find that which isn't there. For a particular search keyword to produce results, it must either appear in the attributes defined as quick search sources or be synonymed in Catalog => Search Terms. And the LIKE search also stumbles mightily on plurals of keywords, something better addressed by using Zend Lucene which is built into Magento, but in a fit of "Buh? What dat?", not used by Magento unless you buy a module to enable it.
Answer: You can manually add search terms under Catalog -> Search Terms. Reindex and cache refresh to make sure you are seeing up to date data.


What alternatives are there to Bracken?

Question: Bracken is the recommended post-processer of Kraken2 outputs and specifically is expected to improve relative abundance estimates. However, Bracken's Github has over 100 outstanding issues and the code seems to rely on Python 2, which is outdated. While many of the github issues are likely not due to bugs, it does seem like the software does not seem to be supported strongly at this time. I am curious what other alternatives exist. Are folks moving from kraken2/bracken to another solution for quick taxonomic hypothesis generation of metagenomics data?
Comment: If you want guaranteed support, then pay for a commercial solution ;)
Comment: Happy to consider that. What commercial solutions do you prefer or pay for?
Answer: No, Braken is the tour de force of first stage post-hoc Kraken2 analysis.
Whether the code is supported or not it corrects bias in Kraken2 population frequency distributions. I'm not aware of any theoretical concerns.
Generally, Python2 isn't a good idea, but it is overshadowed with the bigger concern of population bias, which is what Braken is there to adjust.

What alternatives are there to Bracken?


How to fix Check engine error P0171 on VW Tiguan?

Question: Took the vehicle for service after the usual 7000km.Parts that were changed during the service are Spark plugs, engine oil type 5W-40, Oil filter, Air cabin filter and Air filter. Two days later l got check engine on further diagnosis with OBD2 l get error P0171. The Mechanic changed the spark plugs twice however  the error come back 3 days later. I have checked for loose parts on MAF and PCV Valve fault however to no avail.
Find below freeze frame for error P0171.
Comment: P0171 and higher LTFT suggest a vacuum leak. Do a thorough check for leakage
Answer: As Jupiter states in the comment, vacuum leaks are the most likely cause (particularly around the PCV valve and EGR valve).  Be sure to listen for a hissing sound of air throughout the engine compartment -- around the intake gaskets, brake hose to the master cylinder, small vacuum hoses to the evap system and elsewhere.
Other possibilities:

PCV valve.  This part may be in need of replacement.

Spark plugs.  Verify the correct part number of the spark plugs replaced by the mechanic.  Make sure the spark plug gap is correct.  Check that plugs haven't been cracked, cross-threaded or torqued to the wrong value during installation.

Spark plug wires.  Were the spark plug boots replaced with the spark plugs, as many manufactures recommend?  Has there been a small amount of dielectric grease applied to the boot of the boot?  Make sure spark plug wires haven't been damaged or are shorting, and are pushed onto the plugs securely.  Verify that all spark plugs are firing evenly with a timing light or in-line spark tester.

Dirty fuel injectors/intake valves/O2 sensors.  Add several bottles of fuel injector cleaner to the gas tank and drive the car at maximum acceleration on the highway at least five times.  If fuel trims show improvement (i.e., drop closer to 0.0%), continue cleaning until fuel tank is near empty.  I have seen this sort of problem after spark replacement, caused by the sudden improvement in combustion.

Gas cap.  I have found that a faulty gas cap can go undetected by the car's onboard diagnostics, especially after spark plug replacement or fuel system cleaning.

Throttle body.  Check for air leaks.  It may be a likely culprit if the fuel trim values are also running high on Bank 2.


Anet board - MOSFET replacement?

Question: To learn about printing, and to print the parts for a printer of my own design later on, I've ordered an Anet A8.
I just saw this video, Anet A8 3D printer Review. all you need to know. This guy recommends using an external MOSFET. I was wondering if using a relay instead would also make it safe?
Comment: Do not use a bed which is not made for mains power with mains power.
Comment: What kind of relay are you looking to replace what kind of mosfet, and what current and voltage does it need to deal with? There aren't really enough details in your question currently.
Comment: Maybe one which I can use to power the bed directly through the mains. I've seen some forum posts here and there mentioning that it is possible to use mains power (230VAC over here) for your heated bed, but I have no idea if that is applicable to the bed supplied with the Anet printers. Maybe something like a http://www.digikey.com/product-detail/en/omron-automation-and-safety/G3NA-210B-DC5-24/Z918-ND/206389 ?
Answer: There are two areas of this design which seem to pose a risk of connectors overheating, the hot end and the heated bed. The heated bed runs at about 6 amps, 12 Volts. The hot end runs at a lower current, but can itself overheat if the thermistor stops providing feedback.
The problem in this design with the heated bed is mainly the connectors - they work OK when they are good, but can easily come a bit loose. This has two side effects. The bed heats less well, and the connector itself heats instead. Replacing the 2mm plug connector, and 2mm molex with direct soldered connections will help (the on-board mosfet seems OK with the current, unless you increase the power rail voltage).
A mosfet is a good solution for high current switching, the modules available have good screw terminals which should be OK for maybe 25A (well in excess of what you need). Mosfets are efficient when switched fully on, so there won't be much heating.
You would also use a relay (rated for at least 10A), but this will be noisy since the heater is switched repeatedly to maintain the target temperature. A relay also takes more power itself and will ear out if repeatedly switched under load.
Bottom line, if you have a good relay already, it is OK as a temporary (safe) solution. Longer-term a mosfet is better. Pay attention to the connectors at power supply, board (in and out) and heated bed. Using an additional mosfet for the hotend is maybe overkill.
Comment: The SSR you link is maybe not good for a 12 V load. You'll find mosfet boards on ebay rated for about 30A without cooling, for maybe $10.
Comment: Thanks for your reply. If I'm correct, the drive current on that SSR will not be that high, right? Also your last sentence is a bit hard for me to understand. You seem to indicate that a relay is good as a temporary measure, but then you go on to say that it is a good solution longer term as well. Did you mean MOSFET in one of the two cases? You also mention the connectors. Do you know of any way to improve the connectors? Sorry if I'm asking very obvious questions. The last time I dealt with electronics was in my physics classes almost 20 years ago. It's all a bit rusty.
Comment: Oops, correct. I'll edit... Solid-state relay and mosfet are interchangeable in this context. I was talking about an electromechanical relay...  Connector wise, you want something with eyelet type connections on a M4 bolt, not a 1mm^2 pin with a spring contact.

Anet board - MOSFET replacement?


How to recover deposit to incorrect address

Question: i need some guidance. I deposited Bitcoin from LUNO to an address in Gatehub. The Bitcoin has not arrived in my Gatehub wallet. I believe it went to an incorrect address. How do i trace it and recover it.
Comment: Transactions in bitcoin can take up to an hour, with the ever increasing activity on the network it will take longer incrementallly. But if you send it to the wrong wallet, it is lost and permanently unretreiveable. You are your own bank and that comes with a high price if done incorrectly.
Answer: Log into Luno and click on transactions.

This should list the deposit that you did to gatehub. In my example in the screenshot this is a transfer I did to the waves platform

If you click on that transaction in the list it will show the transaction number of this deposit. The transaction number will be hyperlinked so you can click on it and it will launch a new page that allows you to view the transaction in the blockchain explorer. Check your transaction in the blockchain explorer and see how many times it has been confirmed and whether it has been added to a block.


Is 看上去(他们找到了新的游戏场所) an impersonal sentence (a proposition without a subject)?

Question: I'm trying to do the analysis of the sentence 看上去他们找到了新的游戏场所. I thought that 看上去 was the verb of the impersonal sentence, and that the object was the subordinate 他们找到了新的游戏场所, but I can't find anything about impersonal verbs in Chinese.
Comment: Don't analyze Chinese with English grammar.
Answer: 看上去 is a guess/estimate of what you are seeing - it appears, it seems, or it looks like.

看上去[It appears]他们[they]找到了[(have)found]新的游戏场所[a new gaming place].

The verb here is "找到" (to find), with 了 (an aspect particle) helping to indicate the "completion of the action" and "tense".


Does ubuntu ever clear ~/.cache automatically?

Question: I was wondering whether by default there's anything in place that clears the .cache folder. To my understanding .cache is similar to /tmp, at least I am seeing it being used like that.
Meaning that whatever is in either cache or temp might be reacessed at a certain point or even cleaned up and it shouldn't matter whether it's missing.
Comment: You might want to look into `BleachBit` that'll help you get rid of some unwanted cache and temp files.
Answer: Short answer: no.
It is your cache, so no specific global system process will interfere with it. File manager thumbnails, alt least in the default Ubuntu desktop, will be automatically deleted if they are more than 180 days around (as set by org.gnome.desktop.thumbnail-cache maximum-age) or when the cache exceeds 512 megabytes (as set by org.gnome.desktop.thumbnail-cache maximum-size). How other items in the cache are maintained or handled depends on the application maintaining the cache.
Answer: ~/.cache is not cleared automatically. Each individual application use ~/.cache location to store its own cache data. If it is using more size, you can clear it according to application. If you clear/remove whole directory content, some applications which stored cache won't able to find cache and you might need to restart them. I would suggest to tune application cache for example you can control cache size for browser in browser settings.


Infinite plane background

Question: How would i go about creating as a background for a 3d scene a plane with a texture that stretches into the horzon? I have tried a skybox but i think a skybox will also be needed "behind" the infinite plane.
Answer: It depends whether you need to have an actual geometry that will be seen from close up - if not, you can bake it into the skybox.
In some cases (i.e. when the user has stereoscopic display on their head) you will need to have actual geometry.
Its not exactly clear from your question if you want to create a 'floor' or a 'wall', but in both cases I would link it with player position somehow. A floor could follow players X an Z, while a 'wall' could be made a child to the camera, this way it would never leave the viewport.
Skybox would still be the cheapest by a significant margin, we can give more advice if you provide some additional information. i.e. what are you trying to achieve

Infinite plane background


Why not give tzeddakah before shmittah?

Question: Devarim 15:7 cautions us not to withhold help to others because of the approach of the shmittah year. However, the help we would expect to give would be charity and thus would not be repaid. If tzeddakah is actually a gift, why would anyone not give it in the 6th year because of shmittah? There should be no expectation of repayment that would be nullified by shmittah. Rashi in pasuk 8 (vha'avet ta'avitenu) confirms that the initial offer we should make should be a gift and only turn it to a loan if the recipient won't accept a gift. So why would the shmittah year discourage tzeddakah?
Comment: How did people eat during a shmittah year before modern work-arounds like hydroponics, if their stores weren't sufficient?  If they bought food, potentially at higher prices than what it would cost to grow their own, maybe they'd be tempted to hold extra money back for that?
Comment: from what Vayikra 25 seems to say, everything is available to all people (5-7) and pasuk 19 says that the stores will be more than sufficient.
Comment: Dan, it seems the entire portion is referring to lending.  The Rashi commenting on an allusion of the pasuk that one should initially gift, but the simple flow of words refers to a loan.
Comment: @YDK but that's the problem. It can only make sense if it is lending, but the portion is dealing with the destitute. Is every act of charity supposed to be a loan?
Comment: OK, so your question is that the Torah demands a gift, while the loan is only an option if the recipient refuses a gift, so where does the problem of shmittah arise?
Answer: I think the point is the opposite, that you would think Shmitta is approaching, so you won't lend with any expectation of repayment, so the Torah is saying then give it as a gift, or make it a loan if the person is too proud to take a gift.
However, I would point out that in general the concept of a loan here is really tzedakah that you have minimal reason to expect back. You are not allowed to demand collection of the loan (source and see the whole article for more), not allowed to charge interest and (we see from this posuk) not allowed to assess credit worthiness (to an extent). That is charity wrapped in a loan. However, for the sake of making it a real loan, the lender has real rights to collect the money, it just isn't supposed to happen.
Regarding your comment, yes a loan can be preferable to giving (source).
Comment: but if the loan is really "tzedakah that you have minimal reason to expect back" then why would the upcoming shmittah be a concern?
Comment: @Dan, because you might not view it correctly. This verse is part of what establishes that.
Comment: so this section is less about loans and more about the proper attitude towards loans -- don't give them with an expectation of repayment in ANY year. The fact that I say it about the 6th year proves that all loans should be viewed as tzeddakah.
Answer: According to the Gemara (Makkos 4b IIRC), the only loans which are forgiven are those that are past due. So the person may pay on time (or before Shmittah kicks in)- if he does, I get the whole loan back.

Why not give tzeddakah before shmittah?


My iphone 6 plus is bent and not powering on, need to retrieve data not backup to cloud

Question: First, thanks in advance for any help. I got the new iPhone 6 plus four months ago from AT&T. The phone has been working great the whole time until i sat on it when getting into my car last Friday evening and my phone bent and went dead. I made appointment in the Apple store to set up repair service and they told me they could not retrieve any photos or data that was not backed up to the cloud. I took a family trip to Hawaii to see my son in the military the day after the last back up due to the cloud being full. I cannot lose these photos. I am willing to send in the hard drive somewhere to retrieve this data but cant find where to do this or get the phone repaired enough to power on to retrieve the data. Any thoughts on how to best get this accomplished?
Comment: Give these people a call and see what they say: http://www.drivesaversdatarecovery.com/devices-supported/apple-iphone-data-recovery/
Answer: There are companies out there, although I can't recommend any that claim to be able to recover data off broken iPhones, I've not tried them, the iPhone doesn't have a hard drive, the whole device is on a single computer circuit board, it's going to destroy the phone trying to get it repaired.
Data recovery is expensive, and once your phone has been modified by a third party the price for getting Apple to repair/replace your phone will escalate as they won't do an out of warranty service on a phone that has been modified by a 3rd party unauthorised centre.
In other words you'll have to buy a new phone, and fork out a load of money on data recovery.


I git rm -rf a folder, commited, and then pushed. How do I fix?

Question: I tried to remove a file from git before initial commit using git rm, but it didn't work because it was a folder so I used git rm -rf <file>
Unfortunately, this has left me with no commit history of the file, and it appears to have been deleted locally as well. I went to my trash and it's also not there. This is honestly making me terrified of git and I don't know how to fix it. I can technically live without it, but it was all the source files for a website I made, which makes my life hard. Is there anyway to recover them/generate a src folder from a dist folder, though I highly doubt that?
Comment: You say "before initial commit" ? Do you mean that any files in this folder had never been committed before ? Also can you clarify "no commit history of the file" ? `git rm` does not modify any history.
Comment: It seems like your fear should be directed at your shell.  If you expect removed files to appear in the "trash", then you should not be using a shell.  That, or you should educate yourself on how a shell works.
Comment: Note that you only removed it in one commit, all other commits still contain the file (so no history is gone)
Comment: Yes. I needed to use more characters. Weird.
Answer: Your Problem
If I understand correctly, you had added your files like so:
git add my_dir/*

and before committing them, you removed everything like so:
git rm -fr my_dir

after which everything was gone indeed.
Your Solution
To solve this, proceed like Ikke suggests below:
git fsck --lost-found

And look for lines about "dangling blobs" (your lost files hopefully), like this one:
dangling blob 3a9b15a451d1e77aa262f3379dfb20d235b6f9d4

These dangling blobs will not have any information about the names of your lost files, but should've retained their content nevertheless.
Investigate each blob and recover the content like so:
git show 3a9b15a451d1e77aa262f3379dfb20d235b6f9d4 > my_dir/original_file

References
See also the answer of Alexander Gladysh here: In Git, how can I recover a staged file that was reverted prior to committing? and that of Vi. here: Recover dangling blobs in git.
Comment: Unfortunately, I got no dangling bobs. However, I ran it on a localhost server, and it seems to have been cached from that, mostly. So, I luckily got most of my files back. That being said, I have been looking into backup options and I'm wondering what is the best way to go. The two options that I've explored are backing up my files in atom or backing up my files in gulp. I can do either, but I'm not sure which is best.
Comment: Hm, in that case the formulation of your question must be somewhat off, since "git rm -fr" does not remove files that have never been added. Unfortunately I cannot help you with your question about back-up options.
Answer: To get that folder back, you need to find the last commit that still had it.
Let's imagine it's the second last commit. Then you can recover that folder with:
git checkout HEAD~1 <folder>

HEAD~1 is the reference to the second to last commit. If it's an even older commit, you can increase the number.
Executing this command will get the contents of that folder from that commit and put it in you worktree.
Edit:
You say you never even comitted that file? Then there is indeed no history of it in git, because you never asked git to keep any history.
Did you ever execute git add on that folder? Then the files are still stored in git, though, it's not easy to get them back into files.
You can use git fsck --lost-found to let get search it's object store for unreferenced objects, and it will store them in .git/lost-found.
For blobs, they will be stored in .git/lost-found/other. Inspect those files there and see if you find the ones you are missing.
Comment: But the last commit was no commit, because I removed the files before initial commit. :( Methinks I am screwed.
Comment: Yes, unless you did something like git add on the files, the files are indeed gone. See also my edit.
Comment: Yes, I did git add . and it added the source, which I did not want it to do, which is why I used git rm -rf to removed them after I added them.
Comment: Also, is there a tool or something I could use to prevent this in the future? I was considering adding like gulp-history or something to have another backup, just in case.
Comment: I rangit fsck --lost-found, but unfortunately, I could not find any such file in my .git folder. It did say `Checking object directories: 100% (256/256), done.` but that was it. Perhaps Git doesn't know about the changes? If I am too noob to be able to perform what you are asking on my end, I don't want to waste too much of your time. It didn't find anything. Let me know, if you know another way. Thanks for all your help!
Answer: First off, be aware of the git reflog, which logs not just commits, but no-longer-visible states of git.  Pretty much anything that git actually knows about will be in there.  Check there if you have some doubts.
Secondly, back up your current directory. Copy the whole directory with git somewhere.  Git may already have your back, so this is rarely necessary once you're used to git, but as a newbie, it gives you the confidence to do whatever you need to "unbreak" the working copy without worrying about making things worse.
Ok, so you have a backup of whatever broken or not broken state you created, now you can work on the copy with confidence to figure out what you did.  git reflog and then git branch sOmEhAsH, see if it's what you want and need.  Get the commit and the uncommitted files that you want, and then commit untracked stuff until you're satisfied.
Now, finally, you have to consider whether the push you made is public.  If it is public, and anyone could possibly have already or in the future pulled that commit, you'll git revert sOmEhAsH and undo your mistake.  If no-one else could possibly have received the bad commit, you can do the !destructive! action of a forced push, via the destructive git push -f which will push up whatever you have in the current branch, regardless of what it needs to overwrite in the remote branch.  Use that with care, it's generally not recommended to use on any shared branch.
Comment: OP pointed out he never committed the files in the first place. reflog won't help here. Even if he had commited, reflog is not the right approach here, he can just checkout or reset to an older commit.
Comment: The reflog only tracks references to `HEAD`. This means only when you commit something, or execute some other command that moves HEAD, it will be updated. It will not track the index, nor any random objects.
Comment: Yeah, that's what I noticed. I haven't seen any ways posted online about how to revert to git init state or changes processed before initial commit. I am in a pickle.
Comment: Indeed! I mis-spoke when I said uncommitted, blah.  I meant **not-immediately-visible**.  The point is that once you know about `git reflog`, and have a backup of your broken directory, you know what kind of trouble you're in for.  If it's not in the reflog, you didn't commit it, so you have to deal with the problem from that perspective.
Comment: And what does dealing with the problem from that perspective entail? Does that mean it is not stored, or that I just have to find it differently? Also, why would the file not appear in trash?
Comment: @TimothGass In `git reflog` -> you're golden, which is why it's the first place to look.  Otherwise, you're mostly dealing with a case of having  `-f` **force** deleted a never committed file. If it's no longer in your current directory *as a regular untracked file*, Ikke's suggestion to go fishing for git file blobs may be your only recourse, I've never used those commands personally.


1995 Toyota Corolla Driver's Side Power Window Won't Roll Up, (Stuck in Down Position)

Question: The driver's side window won't roll up. I just want to get the window up for now. I removed the rocker lever on the switch and there's a green LED that's on. The switch doesn't "click" when fully pressed, like the other 3 window switches clicks. I removed all of the components on the door panel, thinking I could just shimmy the window up with my hands, but it won't budge and I can only barely get a grip on it. Is it under tension with a spring or something? Can I disconnect something, pull the window up and then reconnect something to hold it in place? I see a mechanism that looks like it might be an encased coiled spring, with two cables going up and down and each bolted inside the door panel. On top of the possible encased spring is a black cylinder attached with two screws. I don't know if that helps.
Any information would be helpful, thank you.
Answer: Why not just disconnect the switch from the wiring, find the two wires (power and the one to the motor) which operate the window. When you connect the right two, the window will go up, as long as the switch (which it seems is the culprit) is what is bad. You just need a jumper wire to get between the two correct posts and it'll all work. Make sure your jumper wire is of sufficient gauge or it will heat up and cause issues for you ... especially if you're holding it.
Comment: That's a great idea! I have 12g wire, which should work. When I took the switch assembly apart, I noticed a lot of metal tabs. I assume I can find a wiring diagram, and connect power in tab to driver's window up tab?
Comment: @YesterdaysTools - Exactly right. If a wiring diagram isn't readily available, there should be one wire which provides power going out. It should be fairly easy to find as it will most likely be the thickest wire going into the plug. You can verify it with a multimeter. It should read battery voltage with the key on. From there you can test each terminal in the plug until you find the correct one to move the window up.


How to find out who firstly introduced a mathematical concept?

Question: I am wondering if there is any way that one can find out the introducer of a given mathematical concept. For example, if I want to write that "Reduced free groups were firstly introduced in Habegger, Nathan, and Xiao-Song Lin. "The classification of links up to link-homotopy." Journal of the American Mathematical Society (1990): 389-419.", I can only be sure that it has been discussed in the paper but how can I make sure that there is no earlier reference on reduced free groups (Maybe the same name has been used for a different mathematical object, but I am talking about the one introduced in the sense as in Habegger and Lin's paper.)?
Comment: This is good advice @k.stm. I only think "To the best of my/our knowledge" is more common  than "probably" which feels more unspecific and might be taken to imply that you (the author) has some specific doubt, as opposed to only leaving open teh option an error occurred.
Comment: Just add "probably", publish your paper and wait for people to correct you, I would say. I'm very interested in real answers to this, though.
Comment: Thanks @k.stm for the comment! I would rather (within my knowledge and ability) make sure that everything in my paper is correct, instead of publishing it and waiting for correction.
Comment: Publication is usually limited by "accessible bibliographic sources" ?
Answer: Normally the author of the earlier paper(s) should somehow make clear if they introduce a notion or rather continue an investigation giving a reference. So, check what is written in that paper. You can than continue with that older reference, if there is one, until the process stops.
This is however not at perfect method since it would not catch if latter it transpired that some authors thought in error that something is new but it was not.
Another method to complement the first one is to look at what other authors write in the same situation in which you are in. (Or, to ask an expert in the field.)
If in various sources nobody ever mentions anything else earlier, you can assume this is it. In any case you did your due dilligence. It is still possible that something was overlooked by everbody, and there are cases where things were overlooked for decades, but this is rare and there is no practical way in which you can exclude this happening to you.


What does a gate electrode do in the context of a quantum dot?

Question: I am trying to understand the creation of qubits through the use of quantum dots, but I have always had some trouble understanding the function of the gate electrode. I know it can control the chemical potential of the dot itself, but how does it actually work?
Answer: tl;dr section II.E of this paper
The way the gate electrode works is that a conducting metal layer is fabricated in proximity to the dot, with some dielectric separating the two so that charge cannot actually flow between them.  Applying a voltage to the electrode can load it with many electrons, creating an electric field through the dielectric and onto the dot, which adds a constant energy to the entire level structure of the dot.
One particular use of this is explained in section II.E of the paper I linked, called the Coulomb blockade.  The chemical potential says how the energy of the dot changes if an electron is added to the dot.  In the image, each level $\mu(N)$ is the ground-state energy of the dot when there are $N$ electrons in the dot (you have discrete levels because the dot is so small that it behaves like a circular well from QM).  What we want to make is a single-electron transistor, where when I apply a certain voltage, current can flow from the source to the drain, one electron at a time.  For this to happen spontaneously, we would need $\mu_S > \mu_{dot} > \mu_{D}$ so that we promote tunneling through the first and second barriers.  By biasing the dot just right, we create a situation where when one electron tunnels, the chemical potential $\mu(N)$ lies between $\mu_S$ and $\mu_D$ as desired, but a second electron cannot tunnel because the next dot level is too high, so tunneling is suppressed.  Whenever the first electron tunnels out to the drain, the dot level drops so that another electron can replenish the dot.  Sweeping the gate voltage which periodically cause the dot level for a certain number of electrons to be "just right", so that you get periodic spikes in the current, as shown.


How to override the OnDraw Method?

Question: I have an OnDraw method which draws a set of rectangles [ like an indoor map].On the touch event, a new  Activity Intent is called.After the new activity is called,I want to know, how to redraw the rectangles on the buttonClick event( showing a new path in the map).
Below i have mentioned what ive done so far.

1.I have drawn a map on a surface view using DrawRect()
2.Then I catch the rectangle coordinates onTouch event
3.Using a webService, i calculate a shortest path to a location
4.After catching the touched rectangle coordinates, i jump in to a new activity
5.I want to re draw my map(including the path) when i click A button on the new activity

Please give me an idea about how to  override and redraw the On Draw method???
Thank you!
Answer: If I understand correctly, I think you just need to call View.invalidate() on your view to cause it to re-draw. I'm confused as to why you are switching activities, however. It sounds like you should just do your webservice call in an AsyncTask and then in it's onPostExecute(), call invalidate() on your view to cause it to re-draw with whatever data you have now given it.
However, it sounds like you may not have actually implemented your own View class but instead are drawing directly to the surfaceView? I would read up on how to make your own subclass of View. It's really not that hard.

How to override the OnDraw Method?


How to convert an ISO file to IMG format in Linux?

Question: I had downloaded a .iso image of the Ubuntu website and for some official work I need to convert this to .img format. I see a lot of Windows software is available but how do I do this conversion in Linux?
Comment: Does this answer your question? [How to create an .img file from .iso on Ubuntu?](https://askubuntu.com/questions/388037/how-to-create-an-img-file-from-iso-on-ubuntu)
Comment: What program are they wanted for?   The .iso & .img is mostly just part of the filename in POSIX/Linux/Unix; the contents of the file are used to control what the file actually is (some programs do use 'extensions' yes)
Comment: This might be useful: https://askubuntu.com/q/388037/57576
Answer: Actually there isn't any difference between iso's and img's apart the extension. Look at  this link.
So you have to just change the extension.
Answer: To me an iso file is an image (img) file with the iso9660 file system. In other words, iso files are a subset of image files. As a matter of fact, most iso files are synthetic images, not created by making images of drives, but typically made in order to create boot drives in DVD disks, USB pendrives or memory cards.

So I agree with the answers, that you can replace the extension iso with img.
mv file.iso file.img

In order to make an img file accepted by some cloning tool that wants iso files, you could do it the other way too. But in principle that may not be quite correct, because an img file might be an image of a drive or partition, that does not contain an iso 9660 file system (and it might not be an image of a bootable drive). So it could make people confused.
Answer: geteltorito f1.iso > f1.img

TL;DR
I've found an advice to convert iso to img to boot from USB. I was not able to boot from USB with written downloaded ISO. Some time later I found an advice to convert to img via:
geteltorito f1.iso > f1.img

And indeed I was able to boot from USB where I've written img file. The files were different:
$ file 6muj31uc.iso
6muj31uc.iso: ISO 9660 CD-ROM filesystem data '6muj31us' (bootable)
$ file 6muj31uc.img
6muj31uc.img: DOS/MBR boot sector; partition 1 : ID=0x4, active, start-CHS (0x0,1,1), end-CHS (0xe,63,32), startsector 32, 30688 sectors

Boot image sounds like img file:
man geteltorito

geteltorito  is  a  Perl  script  which extracts the initial/default
El Torito boot image from a CD if one exists.
Answer: actually one of the users had posted the answer but deleted it,
the foll. had worked for me:
dd if=/home/asic/ubuntu.iso of=/home/asic/ubuntu.img

Comment: ehm I agree this works but `dd`  is too dangerous for this. a simple `cp` or `mv` works too ;)
Comment: @Rinzwind too dangerous as in?


What was the cause of the cooling system issue in Sputnik 2?

Question: I've heard that there was a problem in the cooling system on sputnik 2.
But, was it an engineering error? Obviously a dog cannot survive  such harsh conditions. Did the engineering team overlook this issue?
Answer:
After reaching orbit the nose cone was jettisoned successfully but the Blok A core did not separate as planned. This inhibited the operation of the thermal control system. Additionally some of the thermal insulation tore loose so the interior temperatures reached 40 C. It is believed Laika survived for only about two days instead of the planned ten because of the heat.

Source: Sputnik 2 - Original from NASA, archived by Google
The mission was a suicide mission for the dog from the get-go, she was never intended to survive. Her quick death was because of the above mentioned malfunction.


What is the Turing degree of Kleene's O?

Question: It's not computable whether a number is a member of Kleene's ${\mathcal {O}}$. What is that set's Turing degree? I can almost see an argument that ${\mathcal {O}} \leq_T \emptyset^{(2)}$ but I can't see how to be sure that the set I'm thinking of is the smallest that meets the criteria. It also seems plausible that ${\mathcal {O}} =_T \emptyset^{(\omega_{CK})}$. Is this known?
Comment: https://en.wikipedia.org/wiki/Kleene%27s_O
Comment: $\mathcal{O}$ is $\Pi^1_1$-complete. Not sure what you mean by $\emptyset^{\omega_{CK}}$. To define jumps at limit ordinals you need fundamental sequences, you cannot just plug in an arbitrary ordinal there. See ch. 1 of vol. 2 of Classical Recursion Theory.
Answer: There is a talk given by Stephen Simpson, located here http://www.personal.psu.edu/t20/talks/pisa0104/talk.pdf, where he discusses the relative consistency strengths of various subsystems of second-order arithmetic $Z_2$. In particular, the theory $\Pi^1_1-CA_0$ denotes a subsystem of $Z_2$ whose set of true $\Pi^1_0$-consequences is of Turing degree $\emptyset^{(\omega^{CK}_{1})}$, which is the Turing degree corresponding to Kleene's $\mathcal O$. However, no proof is given, but I'm sure that one can be found in his bibliography for the talk (or perhaps even in his text on reverse mathematics http://www.personal.psu.edu/t20/sosoa/).
The relevant information in the PDF is on page 29.


Build a PDF document using Cognito Forms and sending it to Sharepoint List as an attachment

Question: Is it possible to build a PDF document using Cognito Forms and push that document to SharePoint List as an attachment? I know that you can send that PDF document to email but not sure if it is possible to send it to a Sharepoint list.
Answer: While you can send custom generated documents to most cloud services from Cognito Forms using Zapier, our SharePoint Integration feature does not currently support adding generated documents as attachments to lists.
However, this is a feature that we are considering and have placed on our public Idea Board:
https://trello.com/c/Xuz1ZLy7/243-allow-generated-documents-to-be-added-as-attachments-to-sharepoint-lists


Managing NFT Royalties Across Marketplaces?

Question: I am working on my first NFT project so sorry if this is a newbie question. I want to deploy my smart contract independently then allow the tokens to be sold on any marketplace platform. The goal is to allow anyone to call the mint function on my contract and create a token, but I (as the smart contract owner) want to be able to collect a royalty on any sales/resales of any token on any marketplace. I am not sure how to accomplish this as it seems like royalties are handled differently by each marketplace. For example it seems like OpenSea allows me, as the smart contract owner, to direct all token sale royalties to a wallet address of my choosing. Is it possible to do this for every marketplace? Rarible looks like they have their own interface for managing royalties on-chain. It would be nice to set the behavior of royalties consistently across all marketplaces. I've looked into the EIP2981 standard but I'm not sure if this is compatible with every/many marketplaces. Any suggestions for how to achieve this functionality?
Comment: hi @nat please follow up, you have an answer here
Answer: Extension of ERC721 with the ERC2981 NFT Royalty Standard is a standardized way to retrieve royalty payment information.
You can see the contract functions here: https://docs.openzeppelin.com/contracts/4.x/api/token/erc721#ERC721Royalty
Royalty information can be specified globally for all token ids via ERC2981._setDefaultRoyalty, and/or individually for specific token ids via ERC2981._setTokenRoyalty. The latter takes precedence over the first.
You can read more about how to implement such a functionality here:
https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments
Answer: Yup.
You will need to register accounts and/or negotiate with every marketplace to get those monies. (Including marketplaces on bridged networks) Then you will need to do your own double account. And then you need to manage payouts of incoming royalties to outgoing accounts.
EIP-2981 may possibly help, more so in the future than today.
This will be a significant undertaking.


visited or has visited this morning?

Question: It is 11:30 in the morning and someone visited me from 10:00 to 11:00 the same morning. Can I say : she has visited me this morning, even though the visit has finished, but it is still morning, or should I say she visited me this morning, or is this only possible when the morning has finished=after 12:00 o'clock? Or are both possible?
Answer: You can say "She has visited me this morning" because it's still morning. And you can say "She visited me this morning" if you are sure she'll not come again until noon or if you feel like the morning is over (and you consider it to be past although technically it's not afternoon yet). That is, both sentences are correct but the use of the Present Perfect or the Past Simple makes the meaning a little different.
Here is what Advanced Language Practice by Michael Vince says about the choice between the 2 tenses:
Choice between past simple and present perfect for recent events may depend on the attitude of the speaker. This in turn may depend on whether the speaker feels distant in time or place from the event.

I've left my wallet in the car. I'm going back to get it.
Here the speaker may be about to return, and feels that the event is
connected with the present.
I left my wallet in the car. I'm going back to get it.
The speaker may feel separated in time from the event, or be further
away.

So, if you feel like her visit is all in the past, you can use the Past Simple.
Comment: by "makes the meaning a little different" you are referring to the attitude of the speaker, whether the speaker feels connected or distant?

visited or has visited this morning?


Sci-fi book about mercenaries who sell advanced weaponry on various planets

Question: I'm trying to find the name of a sci-fi book I read in the 80's. It's about some mercenaries who go to planets and sell advanced weaponry to warring parties. They arrive on a planet of masters and slaves. The masters eat the slaves babies as a rite of passage and have sharpened teeth.
Comment: I'm gonna make a wild guess here.  Could it possibly be "The Men in the Jungle" by Norman Spinrad?  My guess is based on cannibalism and you saying it was "ages ago".  https://www.amazon.com/Men-Jungle-Norman-Spinrad/dp/1490446052
Answer: "The Men in the Jungle" by Norman Spinrad.

All his life, Fraden had been in control, had bent situations, conditions, people, to his own will. He had stood solidly, reaching out to change men and events, but had never been changed by them. He had been booted out of Greater New York, he had taken and lost the Asteroid Belt, and he was still the same Bart Fraden. But on Sangre... something had been done to him. He had been tampered with. For the first time in his life, Bart Fraden felt himself moved by forces beyond his conscious control. Had he changed Sangre? Or had the planet changed him? For the first time in his life, Bart Fraden was afraid.
Amazon, The Men in the Jungle

Credit to Emsley Wyatt for finding the answer.
Comment: Note that you should be able to accept your own answer after 48 hours of asking the question so in ~40 hours. Please do so!
Comment: I didn't want to make my guess an actual answer as I no longer have the book to check details.  The original question could have covered that book, or other books that I'm not even aware of.  But since it was it, glad to help.


SD applications return to Internal Memory

Question: I have a Samsung J7 prime with Android 8.1, the issue is that my applications can be moved normally to external storage, but then it appears again in the internal memory. (when google play store updates the apps). Is there any way to avoid that?
Answer: To avoid updating apps it can be changed in settings when updating is allowed. Or u can shut it down all together then manually run scans to pick and choose which app you want to update.


When you direct output to a file, is that file opened and closed exactly once?

Question: When you redirect the output of a command to a file using >, and that process takes a while (like apt-get update) will the file being written to be opened and closed only once for the entire process duration, or is it opened and closed multiple times (closed when there is no output)?
Answer: It's only opened once, by the shell process that interprets the "> filename" before it starts the command. Since that shell process is waiting for the command to exit, there is nobody to close the file, until command exits.
Output will seem to appear, in bursts, in the file, as disk buffering and caching does its magic.


Is neutron-neutron fusion viable?

Question: Do I get unusual baryon maybe like pentaquark or just a pair of conjoined twin that is very unstable?
Answer: Under isospin symmetry, the dineutron should be a "mirror nucleus" with the diproton and the spin-zero deuteron.  Neither of those are bound (the deuteron has spin $\hbar$, and no stable excited states), and so there's no stable dineutron to fuse into.
Stipe Galic points out the possiblity of the weak interaction process
$$
\rm n + n \to d + e^- + \bar\nu
$$
as the isospin analogue to the proton-proton reaction in the core of the Sun,
$$
\rm p + p \to d + e^+ + \nu
$$
The core of the Sun is dense hydrogen under enormous pressure with a power density of about $100\rm\,W/m^3$; I'll let you work out for yourself the (in)feasibility of observing neutron-neutron fusion under terrestrial conditions.
High-energy neutron-neutron collisions will excite the baryon-meson spectrum in the same way as high-energy proton-proton collisions, but it's hard to make high-energy free neutrons and there aren't pure neutron targets.
Comment: @yippy_yay You've misread the answer. The Sun's matter density is high, but its power density is *low*. For comparison, I metabolize food into heat at about 100 W, and I have a volume much less than a cubic meter.  Removing Coulomb repulsion would speed up fusion in purely strongly-interacting systems, like d-t fusion or the triple-alpha process.  But p-p fusion, and the unrealistic n-n fusion described here, have to wait for the weak interaction.
Comment: FWIW, in the solar core, the probability of a diproton transmuting to a deuteron (rather than just splitting into a pair of protons) is around $10^{-26}$.
Comment: you are not stressing that the neutron is unstable with a weak decay lifetime of the order of 15 minutes, cannot be used as a target except statistically withing neutron rich nuclei
Comment: @annav Fair enough; but even if the neutron were stable I don't think it'd be possible to observe n-n fusion.
Comment: The p+p reaction needs the high power density because it has to overcome the Coloumb-Potential. This isn't the case with n+n.
Answer: Since this has been kicked up by community , I found this link:

The neutron–neutron fusion process,
    n
    n
    →
    d
    e
    ν
   , at very low neutron energies is studied in the framework of pionless effective field theory that incorporates dibaryon fields. The cross section and electron energy spectrum for this process are calculated up to next-to-leading order. We include the radiative corrections of
    O
    (
    α
    )
   calculated for the one-body transition amplitude. The precision of our theoretical estimates is found to be governed essentially by the accuracy with which the empirical values of the neutron–neutron scattering length and effective range are currently known. Also discussed is the precision of theoretical estimates of the transition rates of related electroweak processes in few-nucleon systems.

Here is a reference to an experimental program to study $nn$ scattering, which data would be necessary to use in the theoretical study above.
Comment: Here's a free version of that paper: https://arxiv.org/abs/nucl-th/0507048 Note that "experimental observation of this reaction does not seem to belong to the near future". OTOH, the electrons emitted when *nn* decays to a deuteron have a higher peak energy than those emitted in neutron decay, so it's relatively easy to detect.

Is neutron-neutron fusion viable?


Determing inverse Z-transform using impulse response?

Question: In Matlab there is a command iztrans for finding inverse Z-transform. But how can we find inverse Z-transform using impulse response? The Matlab command impz gives Impulse response of digital filter but how can I then proceed towards finding inverse Z-transform?  Actually i want to determine inverse ztransform of H(z) shown in attached photo. But i want to determine inverse z transform using impulse response since i read somewhere that inverse ztransform can be determined by impulse response using matlab but i am unable to find any google resource that guides much in this regard. I have also attached a table of common z tranforms. I have also highlighted the two most relevant cases as far answer of GKH is concerned
Comment: Could you explain what the question is? inverse z-transform of *what* for what purpose? I honestly don't think your question makes much sense – the impulse response already *is* in time domain, and what you'd typically do with an inverse z-transform is transform something from z-domain to time domain.
Answer: When you have an $H(z)$ (a transfer function), its inverse Z-transform is the impulse response $h[n]$. iztrans is a symbolic function to compute any (causal) inverse Z-transform, either it is related to an impulse response or not. impz is a non-symbolic function to compute some samples of the impulse response of a digital filter.
If I were you and I wanted to find the inverse Z-transform of the given $H(z)$ - which is the impulse response -  I would use residuez:
[r,p,k] = residuez([4 3 9], [4 3 -4])
r =

 1.0544
 2.1956

p =

-1.4430
 0.6930

k =

 -2.2500

That allows you to write the impulse response as $$h[n] \approx -2.25\delta[n] + 1.0544(-1.443)^nu[n] + 2.1956(0.693)^nu[n] $$
given that we're talking about a causal system.
Alternatively, you can use
[h,n] = impz([4 3 9], [4 3 -4]);

but that will give you only a couple of samples of the impulse response.
Comment: how did you write equation/formula for h[n]?i mean how did you define that h[n] is equal to dirac_delta(k)+r1(p1)^n*u[n]+r2(p2)^n*u[n] ??
Comment: That is how this function works. Type `help residuez` to check it. It returns a partial fraction expansion of a rational transfer function.
Comment: "If I were you and I wanted to find the inverse Z-transform of the given H(z) - which is the impulse response - I would use '''residuez''':"  Does your this use of '''residuez'' will be valid for both causal and non causal as well as anti causal inverse z transforms?
Comment: "iztrans is a symbolic function to compute any (causal) inverse Z-transform". It means,we cannot use it for noncausal and anticausal cases?
Comment: Regarding `residuez`, the causal/non-causal/anti-causal interpretation is up to you. The function only performs Partial Fraction Expansion. Finding the impulse response is entirely up to you, according to the ROC of the system you're studying. So actually, the equation for $h[n]$ I derived could be different.

Regarding `iztrans`, as far as I know for MATLAB and Octave, it works for causal signals only.


Copy users and permissions Sharepoint 2010 to new Sharepoint 2013 site

Question: Does anyone have a simple (hopefully free) solution to copy users and permissions from an old SharePoint 2010 to a new SharePoint 2013 site? (I can move content with no issue).
This could be through powershell or via a software solution, much appreciated.
Comment: What about migration? :)
Comment: I don't mind migrating....but I would like to test first before migrating users and shutting down the original site.
Comment: okay so just make an copy of your 2010 database and add to your 2013 environment.... mount the database with "mount-spcontentdatabase"... than use move-spuser to migrate the users to your new environment... (be sure you enter the correct alias)
Comment: Ok I have now been told IT manager wants us to go from SP 2010 to SP 2016 and to using SQL server 2016 in background.....would Sharegate or a solution like that be our best bet? Just looking for the easiest less fuss method
Comment: in my opinion, the savest way is to migrate from 2010 to 2013 and then to 2016, cauze you cant migrate from 2010 to 2016 in one step...
Answer: As a workaround, please try doing the migration following the scenario "Convert SharePoint 2010 Products classic-mode web applications to claim-based authentication in SharePoint 2010 Products and then upgrade to SharePoint 2013":
https://technet.microsoft.com/en-us/library/gg251985.aspx?f=255&MSPPError=-2147217396
Also get help from this article for SharePoint migration.
Hope this helps!
Answer: Yep, I've done it with Sharegate before! If you don't mind migrating you can check out these docs: https://support.share-gate.com/hc/en-us/articles/115000597627-Copy-User-Permissions and https://support.share-gate.com/hc/en-us/articles/115000598267-Copy-Users probably the easiest/fastest way to do it and they have a free trial period too


Will expanding my Synology Hybrid RAID delete the data on the initial disk?

Question: As the title states, I currently have my Synology NAS with a single 4TB drive in it. I now wish to expand this with another 4TB drive. If I expand the volume (it's currently setup as SHR) will the initial disk be erased? I know it says "existing data will be erased" when you select the new drive, but I'm not sure if it means only on the new drive or both the new and the existing drive.
Answer: No the existing data will not be erased when you add a disk to the SHR array.
The message is simply saying the new drive being added will be formatted.
Your data and applications will actually remain available during the expansion process; there is no need at all to even stop using the NAS whilst SHR Vertical Expansion is taking place.
That said - before any type of RAID manipulation (of any flavor) you should backup first.
Finally it is probably worth pointing out that if you are using two equally sized disks there is no point at all using SHR over RAID1 - indeed you should use RAID1 as SHR will incur an overhead in both read and write speeds compared with RAID1.
The real advantage of SHR comes when using odd sized disks.
Comment: Even if having the same size disks, it might be worth using SHR from the outset because in the future someone might want to add a larger sized disk to the array.  Do you know what performance difference SHR has compared to RAID1?
Comment: That is a fair point - if you did plan on having odd sized disks in the future then SHR could be a good option. As for the performance overhead I had the figures somewhere, will post back with them. As far as I remember it was about 10% slower read/write - so no too significant, but far from trivial either...
Answer: I cannot say specifically, however - if you add a disk to a RAID config, it'll need to be wiped to become part of your RAID. Losing that data is - as you surmised - inevitable.
When it comes to the original data though, the answer is a little more complex - RAID, depending on type, will differ in where it writes data in a two drive configuration, as opposed to a one drive config. (Aside from straight mirroring). This means your array needs to re-layout the data on the disk; the simplest way to do this is reformatting, wipe everything and start again.
That's not particularly useful for most people, so a lot of RAID devices do on the fly rebuilding - they effectively have to when you replace a drive anyway.
Referring to: http://www.synology.com/en-uk/support/tutorials/559
I note that it says:
For SHR volumes, storage capacity is only expanded when adding hard disks to a volume with two or more disks.
So you may simply be adding redundancy by adding a drive. A spot of googling suggests this to be true - 2 disk SHR is basically RAID1 - mirrored data, no capacity. As such, it's extremely unlikely to be losing any of your source data. (But won't be giving your more capacity either).
If you want to increase capacity, you'll need to switch to RAID0. However this has a very significant caveat - RAID0 does not protect your data. It is WORSE than a single drive for reliability, because if either drive fails, you lose data. RAID0 is generally a bad plan for anything you care about keeping.  (And from a brief bit of digging, swapping RAID types is destructive).
Comment: Thanks for the input, I guess I'll backup the info to USB HDD first and test out the theory, I'll come back and mark it as the answer should it be correct (which I'm sure it probably is!)
Answer: I wanted to add the knowledge that using SHR 1-disk fault taularance (1 Disk FT) is the best for home and small businesses as it allows you to epand one drive at a time, handles power-outages while rebuilding your array, and once re-built it will have the option to expand your total volume size of your array.
Remember, SHR only works with Synology NAS robots at the day of writing this, Jan 17th 2018, as it is a patented software RAID technology programmed by that company.
Enjoy SHR 1D FT! I have, for over one year now. Running:

Disk 1 4TB
Disk 2 3TB
Disk 3 2TB
Disk 4 3TB

Currently I have 7.67GB volume size (that's 8TB rounded), and going to expand to 9TB next week by inserting a newly purchased 4TB drive in the Disk 2 slot.
Comment: +Added commment: Decreasing HDD size is not allowed with SHR. For example, in the above configuration, if removing Disk 1 and insterting a 3TB disk, the Synology Disk Manager (SDM) program will say to you: You must instert a disk of 4 terabytes or larger. In my model, my Synology NAS only allows 4TB disks as a max, so Disk 1 slot is expanded fully already.


I can't join servers on Counter Strike Global Offensive

Question: I double click a server to join and most of the time a box comes up saying join game, refresh, cancel and the server information so I click refresh then join game but nothing happens and sometimes when I click favourites nothing shows up.
Comment: You can edit your posts using the edit button you see below the tags. I've made the edit for you this time
Comment: Are you doing this from steam? or with the game already launched?
Comment: Is the server full?
Comment: Give more details and screenshots if possible
Comment: Can you note your OS and platform? Also router model if you can determine that.
Answer: Is this for both casual and competitive? If so, I suspect you are being blocked by a firewall. Either on your computer or at your router.
The easiest way to determine if this is the cause (before putting in a permeant, correct fix) is to turn off the firewall on your computer (this differs between Mac and Windows). Try the game. If the problem persists, try turning off the firewall on your router (do not leave this off, turn it back on right after testing regardless of result). Note that some routers may not have this option but how to do it would be in the manual of your router. You'll need admin access too.
Turn both back on.
If turning off either of those allowed you past the problem, you need to identify the ports that CS:GO uses and open them.
Writers Note: I'm aware this this shouldn't be needed (as most firewalls should allow such traffic) however, it's a logical conclusion based on the info we have and worth the OP following up on.
Comment: I can help identify the ports if this proves to be the trouble. You might find the info in the interwebs too.
Answer: If that box appears it means you're trying to join servers that are already full.
I would suggest using the filters at the bottom and checking "Hide full servers" to avoid this issue.


ODBC Driver Version 03.86.3959 connection to SQL Server 2014

Question: Ok so I have some accounting software running on a Windows Server 2003 box. This server uses a System DSN, that uses Microsoft SQL Server ODBC Driver Version 03.86.3959 to connect to a Management Information System, which is running on SQL Server 2014 on a Windows Server 2012R2 box.
I create the System DSN from scratch using the ODBC Data Source Administrator. I have tried both integrated security and the sa login for SQL Server 2014. Both these are set up correctly as logins on the SQL Server with linked users. I have also tried putting the server as the IP and the dns name.
When I try to run the connection test, I get an "SSL Security Error".
I can ping the 2012R2 box from the 2003 box.
So I am wondering whether I need to update the ODBC driver on the Server 2003 box to ODBC Driver 11 for SQL Server. The problem is that the system requirements for this ODBC driver do not include Windows Server 2003 -- only Windows 7, Windows 8, Windows Server 2008 R2, Windows Server 2012, Windows Vista Service Pack 2 are listed as supported operating systems.
I have searched online for some compatibility charts with ODBC drivers and SQL Server versions but have not been able to come up with anything. Any help would be much appreciated.
Answer: It was what I thought. I updated the ODBC driver on the Server 2003 to the one in the Microsoft SQL Server 2008R2 SP2 Feature Pack and it worked fine. This version of the ODBC driver was old enough to work on Windows Server 2003 but yet new enough to be able to connect to SQL Server 2014.


What does "fit" mean in "survival of the fittest"?

Question: What does "fit" mean in "survival of the fittest"?
Comment: This is a very vague question. What aspect of fitness do you not understand?
Answer: 'Survival of the fittest' has never really made sense, because it confuses the scientific (evo. biological) and colloquial definitions of the word - which some of the previous posters have also done.
Biological fitness simply refers to an individuals genetic contribution to the following generation. That is, a 'fitter' individual, in an evolutionary sense, is one whose genetic material is proportionally overrepresented in the next generation.
The mechanism by which an individual achieves this may include out-surviving competitors, but it's certainly not the only way to increase fitness. Two individuals may live for the same length of time, but one may successfully court more females, or out-compete the other for food resources, for example. So when we refer to a 'fitter' individual (or individuals), we're saying nothing about why they are so. It's not a comment on their 'fitness' in the human sense of the word (bigger, stronger, longer-living), it simply refers to how well they pass on their genetic material.
So you can see why the phrase is nonsense. If we're being precise, then 'survival of the fittest' translates to 'survival of the individual who is better able to pass on their genetic material to the next generation' - which is meaningless because it tangles up these different concepts.
Comment: "Survival of the fittest" is a misnomer.  It's "Reproduction of the fittest".  Nobody survives in the end :)
Comment: +1 for paragraphs 2 and 3. However, I wonder, does being recursive/tautological still make it "nonsense"? [Hesperus is Phosphorus](http://en.wikipedia.org/wiki/Frege%27s_Puzzle)
Comment: I would have liked to write an answer, but the question is closed already. Anyway: "fittest" is the one that "fits most". It has nothing to do with strength or endurance, but (popular example) it can be a fly without wings on a stormy island.
Answer: Simply put, "fit" refers to being adept at finding and utilizing resources, evading predation and producing offspring.
Answer: It might sound tautological, but fitness is pretty much defined as 'being more likely to survive - and reproduce'; fitness is surviving and survival goes to the fittest.
This is a trite way of citing Richard Dawkins' theory of the replicator to describe fitness.
Fitness is a property of being able to carry one's genes to a later generation.  Fitness is result of the individual properties and how well the individual can get along in the environment that it finds itself, in comparison to other individuals who might be competing for resources in that environment.
There is no concrete definition of fitness.  Fitness can mean size and strength, or lightness and resilience, short or long life.  There is no a priori way of looking at two individuals you know nothing about and deciding which is going to be more successful at reproducing.
not sure this is better, but there's definitely more of it...
Comment: I still think you're off the mark, particularly in paragraph  4. There is a fairly simple definition of biological fitness, namely, an individuals relative success in passing on their genetic material (as I've outlined in my answer). And no, biological fitness can not '...mean size and strength, or lightness and resilience...'. Those are factors which may *influence* fitness but they are not integral to the definition of 'evolutionary fitness', which is what we are discussing. Measuring fitness can be very difficult, which you rightly touch on at the end, but defining it is simple enough.
Comment: Survival of the one, who is more likely to survive. That's recursive. Can you elaborate?
Comment: @Zurechtweiser: I think there is a bit of confusion on the fact that it is not the survival of a specific individual *per se* which is important, but rather the survival of its genes in the population. There is no recursion there, the individual(s) who are more likely to transmit their genes (i.e. to make them "survive" to next generations) are the fittest.
Comment: you're right that this is a bit trite - i had only a minute or two to tap something out.  I've added a bit more.
Comment: It's worth reading [the Wikipedia page](http://en.wikipedia.org/wiki/Survival_of_the_fittest) on this.
Comment: Also recommend "The Extended Phenotype". @ThomasWhite I think this is what I said.  I did change one word tho.
Answer: Rather than "fitter", I'd say "better". Better at hunting, gathering food, surviving predators, surviving weather conditions or other kinds of population pressures. The better a population gets at the above things, the more (and fitter/better) offspring it is likely to have and the pyramid goes on.
In some cases, mutations might simply confer a "new" advantage that there was no prior pressure in the system for. For example, I can easily imagine a bird population where one of them evolves a plumage/pigment mutation that gives it a selection advantage and it quickly becomes the norm. This mutation could have - theoretically, and in my view - evolved even in the ABSENCE of a sexual selection pressure.
It's just that natural selection (in my simplistic interpretation) "favors" any improvements in organisms in a really simple, statistical way.
Answer: Often it is re-phrased "Survival of the Most Adapted."  Fittest might make you think of the strongest or the fastest, but suppose in extreme famine, those who had better regulation of muscle growth could have more surviving generations.  In an over abundance of resources the reverse could be true.
Ultimately in natural selection, it's all about getting your genetic information to as many surviving copies or permutations as you can. Many organisms use DNA to hold the information, but there are other options (RNA viruses for example).
Getting back to the phrase: It's saying that the fittest is the one who continually replicates well in the current environment/surroundings.  Ecosystems are often changing, thus who has the best fitness will change as the ecosystems changes.  When an ecosystem is stable for a long period of time, you will find highly adapted organisms to that ecosystem.  This is because the selection towards "fittest" has been applied to many, many generations.
Comment: Whoops I just saw the previous two answers come up while I was writing.  I won't be insulted if people think this should be delete as too similar.
Answer: While, as others point out, "survival of the fittest" is a pithy description of the theory rather than an actual serious statement I think it can be converted to a useful definition relatively easily.
There is substantial debate about how, exactly, fitness should be defined. I'm not enough of an expert to want to try and lay out the complications here but I will give my preferred definition:

The fitness of an organism is defined as the number of its
  grandchildren that make it to adulthood (or that number divided by two
  for sexual organisms).

This has the advantage of being amenable to experimental investigation and intuitively simple while complex enough to avoid simple problems arising from the differences in offspring number and the question of infertile offspring.
Comment: Where is that definition coming from?
Comment: A book on the philosophy of evolution I read a while back. I don't have it to hand to give you a reference.
Comment: Such definitions will always be lacking, in my opinion. For example, what if an organism has tons of grandchildren but they are all sterile?


Maintenance requirement

Question: I just deposited $600 in my TD Ameritrade account.  I bought three stocks for $545.  On the box it says $195 maintenance required.
Does that mean that I have to deposit an additional $195?
Comment: I'm not familiar with TD, but I see this: "A 40% maintenance requirement may be needed if a position represents 70% - 100% of the total marginable long value and short value. A minimum of $2,000 is required to open a position on margin. A minimum of $2,000 is required to maintain a short stock position."   --  https://www.tdameritrade.com/retail-zh_tw/resources/pdf/AMTD086.pdf
Comment: *On the box it says...* On what box?
Comment: Can't speak for the OP but on my Account Summary page, it lists the margin requirement in a **box**.
Answer: For starters, Ameritrade has a higher margin maintenance requirement (MMR) than Reg T (30% vs 25%).
The amount of MMR per position depends  on the price of the stock so you can't look at the total MMR and work backwards and determine the amount the MMR per stock position.
$195 divided by $545 is about 36% so my guess is that at least one of your positions has a share price of  less than $4 (higher margin requirement).
In answer to your question, if you have $600 in your account and you buy less than $600 worth of securities, you would not be on margin and would not have to deposit additional cash.  The MMR is just a calculation letting you know the minimum equity that you would need to carry the positions.
And as Hart Co mentioned, Reg T minimum account value is $2,000 for margin so I'm going to guess that you have other securities in your account thereby allowing you to meet the $2k requirement.  If not, I have no clue how you could buy on margin with $600.
The short answer? Call TD Ameritrade to verify all of this.

Maintenance requirement


System of differential equations $x'=f(y-x),\, y'=f(x-y)$

Question: I have a problem regarding differential equations, $f$ is increasing. $x,y$ are dependent on $t$
$$ f(0)=0 $$
$$x'=f(y-x)$$
$$y'=f(x-y)$$
$$x(0)=1$$
$$y(0)=0$$
prove that when $x,y$ are the solutions of this equation then $$ \lim_{t \to \infty} x = \lim_{t \to\infty}y $$
So far I have managed to see that $x'(0)=f(-1)$ and $y'(0)=f(1)$ which implies that $x'(0)<0$ and $y'(0)>0$ and basically $x'(t)<0$, $y'(t)>0$ as $x>y$ so as $f$ is increasing and $x$ is declining with $t$ and $y$ is increasing with $t$, the derivatives of $x$ and $y$ will be declining and increasing respectivly and they will have the boundary. Can anyone help from this on?
Answer: First we note, that $\lim_{t\rightarrow \infty} x = x_\infty$ indeed exists. This is because $x$ is decreasing monotone. On the other hand $y_\infty$ exists aswell. We have $x_\infty \geq y_\infty$, because if there is a $t_0$ with $x(t_0)=y(t_0)$ we have $x'(t_0)=y'(t_0)$ and this will be $x_\infty$.
Now assume that $x_\infty >y_\infty$. The genral solution of a differential equation is:
$$x(t) = x(0)+ \int_0^t f(x(t)-y(t)dt$$
But we then would have
$$\lim_{t\rightarrow \infty} x(t) =x(0) +\int_0^t f(y-x)dt \leq\lim_{t\rightarrow \infty} x(0) +\int_0^t f(y_\infty-x_\infty)dt =-\infty $$
This however contradicts that $x_\infty>y_\infty$
Answer: Let $u=y-x$. Then
$$
\frac{du}{dt}=\frac{dy}{dt}-\frac{dx}{dt}=f(-u)-f(u)
$$
Which is automatic with an equilibrium solution $u=0$. Note that your initial conditions become $u(0)=-1$
For $u<0$ since $f$ is increasing $f(-u)-f(u)>0$ giving $u$ is increasing (for all $u<0$). Assuming $u$ is a continuous solution it would need to pass through $u=0$ but cannot actually exceed this value because of the equilibrium there. so $\lim_{t\to \infty} u=0$ Thus $\lim_{t\to \infty} y-x =0$. So if either of the limits $\lim_{t \to 0} x$ or $\lim_{t \to 0} y$ exist (and are real) they must be equal. If they're $\pm \infty$ they also must be the same one.
Comment: I dont get why it would have to go through 0, why boundary can not be -1/2?  for instance u would be an arcus tangens scaled properly
Comment: That argument is not sufficient, you first have to show, that 0 is the only possible limit
Comment: Any other limit $L<0$ would have to also be an equilibrium solution (that is $\frac{du}{dt}=0$ ) and $\frac{du}{dt}$ is strictly greater than zero for negative values of $u$
Comment: @ryszardeggink By "boundary" you apparently mean "limit"?
Comment: yes, but the problem is already solved :)


Beef casserole partially cooked this morning and left in the oven to cook later - is this OK?

Question: I partially cooked a beef casserole this morning (about 8am) and left it in the oven to finish cooking between 4pm and 6pm tonight.  Is this going to be OK? or will I make my family ill?
Comment: It depends on how far it was cooked. Was the meat still rather raw or was it nearly done when you turned the oven off. There are meals I always cook for 2/3 of the time they need in the morning then turn the oven off. In the evening, while I make the side dishes I reheat the oven.
Comment: Did it get below 140 F?
Comment: You would do better to use a slow cooker.
Comment: Casseroles are usually pretty well suited for fully cooking, then reheating, which would be the route I would take if I was going to have it sitting around.  Did you leave it in the oven so you could set the timer to get it going while you weren't there?
Comment: Many people do it.  Many people get away with it.  But it only takes one time of something going wrong to make you sick.  I would stick to those USDA guides.  Will it kill you?  Probably not.  Do you really want to take those chances though.  Mild cases of food poisoning are still not much fun.
Comment: Yes andrew I left it in the oven with the timer going.....well we all ate it and we're all fine today - I might do it another way next time
Answer: If it was cooked and stayed above 140 °F then you are fine.
If you just turned the oven off then it was probably below 140 °F for 2 hours and entered the danger zone.  90 °F to 140 °F food should not be left out more than 1 hour.  Even then it is supposed to be fully cooked first.  Is it safe - maybe?  Definitely in the range for bad stuff  to grow.
Below is from United States Department of Agriculture
"Danger Zone" (40 °F - 140 °F)
Leaving food out too long at room temperature can cause bacteria (such as Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli O157:H7, and Campylobacter) to grow to dangerous levels that can cause illness. Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the "Danger Zone."

Keep Food Out of the &quotDanger Zone&quot
Cooking
Storing Leftovers
Reheating

Keep Food Out of the "Danger Zone"
Never leave food out of refrigeration over 2 hours. If the temperature is above 90 °F, food should not be left out more than 1 hour.

Keep hot food hot — at or above 140 °F. Place cooked food in chafing
dishes, preheated steam tables, warming trays, and/or slow cookers.
Keep cold food cold — at or below 40 °F. Place food in containers on
ice.

Cooking
Raw meat and poultry should always be cooked to a safe minimum internal temperature (see graphic). When roasting meat and poultry, use an oven temperature no lower than 325 °F.
If you aren't going to serve hot food right away, it's important to keep it at 140 °F or above.
Storing Leftovers
One of the most common causes of food-borne illness is improper cooling of cooked foods. Bacteria can be reintroduced to food after it is safely cooked. For this reason leftovers must be put in shallow containers for quick cooling and refrigerated at 40 °F or below within two hours.
Reheating
Foods should be reheated thoroughly to an internal temperature of 165 °F or until hot and steaming. In the microwave oven, cover food and rotate so it heats evenly.
Comment: There is no reason to recreate this content. That's why we have duplicate closures and why we have the canonical answer. If you want, you can add an answer there.
Comment: @Catija You feel left at room temp is the same as this question.  I don't.


How can I improve my turns when downhill skiing?

Question: How can I improve my turns when downhill skiing?
Whenever I make passes back and forth, my uphill ski is at an angle and is awkward, often causing me to stumble.  I would have much better control if I could learn to turn both skis at the same time and keep them aligned.
Answer: You will need both Technical and strength drills.
You should strengthen your core/torso strength, as that's where most of the movement is coming from, using drills such as squat, lunges, wall seat and more (you can see a good list here).
You will also need to improve your technical aspect of the movement (I assume you mean your carving of the snow with both legs - what's called: Parallel ski). There are some gym exercises with specific equipment that can help you master the movement.
Answer: I am a learning skier as well and generally that happens when I involuntarily lean, even slightly, back on turns especially when on harder slopes.
Make sure you are turning in the correct position, you have pressure on the front of your boots.


How to add Google Earth Engine data to Google Earth

Question: I just found out about the Google Earth Engine Catalogue and there are a few datasets that I want to take a look at. Is there an easy way to display some of these datasets in my desktop version of Google Earth? I would prefer not to download all of the datasets and then import them into Google Earth.
Comment: It's a little unfortunate that the names are so similar, but the products are unrelated.  You can't add Earth Engine data to Google Earth Pro without exporting to a local file (geotiff) that I'm aware of.
Answer: In addition to exporting a GeoTiff and loading that in Earth Pro (as mentioned in a comment), for larger datasets you can export a map tile set from EE, and load it into the Earth web client using the new Tile Layer functionality.
But generally, it's probably better to preview Earth Engine (EE) datasets in the EE Code Editor.  In fact, for most datasets in the EE Data Catalog, if you look at the bottom of the data page there is sample code that you can copy and paste into the code editor to preview the data, or just click the blue "Open in Code Editor" button.
Note that many of the datasets in EE are multispectral or other types of data, and are not natively RGB color images that can be directly viewed.  So for most of them you need to process and add visualization parameters before they can be visualized on a map... that's what the sample code is for.
Comment: Is there a better application than google earth (but which unlike EE code editor would live on my desktop) that can do things like view multispectral band imagery? But which would also just have google earth's satelite imagery build in?
Comment: There are several GIS packages like QGIS and ArcGIS which can view and manipulate multispectral imagery. They don't have Google Earth's imagery built in, but they do have some options for imagery basemaps through associated services or plugins.


Passports Thailand

Question: My partner, who is Thai, has just become an Australian citizen. He is not supposed to hold both. We are going to Thailand. Should he travel on the Australian passport or should he use both passports? Would he leave and reenter on his Australian passport and enter and leave Thailand on his Thai passport? Would there be any problems at the Thai end?
Comment: My suggestion is better, as it is an intentionally generalized Q/A, rather than one worrying about particular intricacies of the UK/Saudi situation.
Comment: @CMaster should OP use the "dual citizenship okay" advice, or "not okay"?  Thailand's prohibition of dual nationality for its citizens elsewhere is apparently not enforced very strictly.
Comment: @jcaron the Thai attitude towards dual nationality is apparently somewhat different from the Saudi attitude.
Comment: @phoog No idea, seems op would be better placed to understand that one.
Answer: If he has not formally renounced his Thai citizenship, then he is still Thai and should use his Thai passport to enter and exit Thailand.
He should use his Australian passport to exit and re-enter Australia.
I am not well versed in Australian citizenship law, but there is a reference on the government website that mentions a permanent resident of Australia could be come a dual citizen by becoming an Australian citizen, which to seems to me to mean your partner may be able retain his Thai citizenship - http://www.border.gov.au/Trav/Citi/Curr/Dual-citizenship
Comment: You haven't mentioned Thai law.  In fact it appears somewhat complicated.  Thais who naturalize elsewhere are technically supposed to lose their Thai nationality, but in practice it seems that this rarely happens.
Comment: As you alluded to, Thais rarely lose their nationality as a result of accepting other citizenships.  All of my wife's friends (she is Thai) who have married, moved outside of Thailand and gotten citizenship in their new home countries stll maintain their Thai citizenship. tit

Passports Thailand


Outdoor string lights plug adapter?

Question: My back porch does not have any external outlets. The porch light has this F13BX/827 double LED light, which is requires a 2 pin gx23 base. I was wondering if there are any adapters that can go into this base and have an outlet on the other side (for string lights). I know they have them for traditional incandescent bulb bases, but I wonder if anyone has found one (link, please) for the aforementioned one.
Comment: that looks like a fluorescent light
Comment: I don't know of one and would be surprised.
Comment: How is the fixture mounted? It might not be that hard to connect a receptacle in a box next to it, though it would likely end up switched along with the existing light. Also, any new outdoor receptacle (but not, generally, lighting) needs GFCI, and you can't put GFCI high up, so you would likely then need to have the circuit GFCI protected earlier (e.g., at the switch or the breaker panel or in between).
Comment: There seem to be gx23 to e27/e27 adapters.  If they are safe or legal will be up to you to find out.
Comment: I dont think so, I didnt find any for a similar situation with another fixture.  Also the rest of the fitting will probably have a ballast and starter.  Theres more to it then an adapter.
Comment: This is off topic for here.
Answer: There may be physical adapters available, but they won't work like you expect. This socket type is connected to a ballast rather than directly to line voltage. That means even if you physically adapt the pins, you can't treat it as a regular wall outlet because of the ballast. If you want an outlet in this location you will have to change out the fixture for one that does not use a ballast, install an extension ring with an outlet (and add a GFCI) or wire in a whole new outlet and circuit. There's one other super-hacky option: you can bypass the ballast and change out the bulb for a 'ballast bypass' LED type. Then a socket adapter will work. You still won't have a GFCI, so it's of course dangerous compared to a proper outlet, but it will let you hang up string lights. Just know that it's not a great way to go because of the shock risk. Outdoor electric shock risk from plug-in devices is significant enough that GFCIs have been standard there for 30+ years.

Outdoor string lights plug adapter?