Enjoy- Intransitive / transitive verb

Question: I know that Enjoy is always used as a transitive verb and only as an intransitive in imperative sentences in some specific context. However, as native speakers, do you think enjoy is correctly used in this sentence: '' Enjoy upon your personal preference'' (it's written on a noodle package), or should it be '' Enjoy it upon your personal preference''?
Comment: No; that sentence makes little sense. Something seems to have got lost in the translation.  Incidentally, "enjoy" can be used intransitively with a clausal complement, e.g. "I enjoy going to the theatre" / "I enjoyed working with you".
Comment: Though some would say clausal complements are objects, making _enjoy_ transitive in that case.
Answer:
"Enjoy upon your personal preference"(it's written on a noodle package), or should it be "Enjoy it upon your personal preference"?

The sentences are both what is known as "Chinglish" - See https://en.wikipedia.org/wiki/Chinglish

Chinglish is slang for spoken or written English language that is influenced by a Chinese language.... This term is commonly applied to ungrammatical or nonsensical English in Chinese contexts]

Examples of Chinglish can be found on the internet. The site LTL Mandarin School has a selection with the explanation of how the mistranslation has arisen and why the Chinglish is wrong.
Chinglish is seen as a problem in China and the Shanghai Commission for the Management of Language Use has had a drive to eradicate it since 2008.
"Upon personal preference" is not idiomatic, and, as used, seems to be a very poor and/or literal translation of a Chinese phrase.
Comment: @Lala "Enjoy them the way you like them best!"
Comment: Thanks for your clarification :) Could you please suggest a proper phrase that has the same meaning?
Comment: "Enjoy, according to personal preference" is the correct translation if you use Baidu translate and reverse the process then re translate, this is what you get. Which makes perfect non "Chinlish" sense to me. The origin of upon no doubt occurs from a mistranslation which would have read Enjoy "deciding upon" (phrasal verb) your personal preference.
Comment: "Enjoy, according to personal preference" sounds odd to my (British English) ears. "Enjoy, according to your personal preference" would be better. "Enjoy this according to your personal preference" better still, but the last two are certainly grammatical.
Answer: Although I agree with BillJ in his sentiment.
I would answer your question.
*or should it be Enjoy it upon your personal preference
if you use it in your sentence, then what is it?
you have no object therefore presuming you mean the noodles the sentence would have to be written Enjoy the noddle's upon your personal preference
Regardless of the original sentence not being correct You cannot just add it
Comment: Thank you!!! :)

Enjoy- Intransitive / transitive verb


Send throttling large list

Question: We have a list of 13 million contacts and want to throttle the email to limit traffic on the landing page. We want to make sure everyone receives the email on the same morning. My concern is that there is a max limit on throttling because the hourly threshold dropdown only goes up to 500000. If we use only the delivery window as below can we expect the whole list to receive the email in 4 hours?
Answer: Simple answer is: No, you can't guarantee delivery of all your messages within this timeframe.
There are many factors affecting the email throughput, including but not limited to multiple lookups in large data extensions (e.g. including product information based on SKU/historical orders) or outbound API calls from Ampscript at sendtime (God forbid).
Have you sent a similar email to same size of audience before? You should be able to look into the _sent and _job data views to see when your first and last emails were sent out.
Otherwise, you can do a test send of this email to an audience 10% the size, utilising the black hole domain of Marketing Cloud (e.g. firstname.lastname@example.com, firstname.lastname@example.com) and measure it. Keep in mind, this will both consume supermessages and create these recipients as contacts in your MC instance, so you will need to clean these up afterwards.
Setting the sending window will not spread the sends evenly within these hours. It will only ensure emails are NOT sent outside these hours.
Comment: cool. i deleted my own answer about this, this would just have led to confusion. cheers
Comment: I agree there is never a guarantee. Suppose that similar sendouts have been done before in that account without taking HOURS to complete, say 13 mio have been observed in 30 minutes,  simply _not checking_ the "hourly threshold" option, but setting a window of, say, 4 hours, this would be a way to spread it, no? Basically, if you leave "hourly threshold" unchecked, no "cap" on the sending will be set other than performance limits, and the sending will be done _as fast as possible_ (whatever that means for your configuration), just spread over multiple points in time, no?
Comment: Good comment. I have updated my answer accordingly, @JonasLamberty
Comment: We do regularly send to same size audiences. It takes about 30 minutes indeed. @LukasLunow, if we set sending window 4 hours, will the sendout still complete around 30 mins?
Comment: That's correct @aca
Answer: As @LukasLunow stated, Send Throttling is not going to fit your needs and will space your send out across days (around 7 I believe) if you use that 4 hour window with the max segment size.
To spread things out to what you need, I would instead recommend splitting your audience into 'chunks' whether through the UI with the 'Random Split' DE option or via SQL.
Lets assume you are breaking 13 mil into 4 different segments.

You would split and have DE1, DE2, DE3, DE4 for your audience. (each with around 3.3mil records in them)
I would create a send Activity inside Automation Studio for each of these with the correlating DE as the sending audience.
Then I would create an automation to hold these segments.
Inside this automation I would have Send Def. 1 then put a 1 hour wait activity, then Send Def. 2 and another 1 hour wait activity, etc. until you have them all in there.

You then schedule this automation to begin when you want it and you will now have an hour (plus time it takes for send definition to run) between each send.
You can adjust the split and time periods to meet your needs, but this will let you fully control the delay in both timing and audience size beyond what is available in throttling.

Send throttling large list


Looking for a title of a sci-fi novel or story where a government department's job was to slow things down

Question: I read a sci-fi novel or novella about a man that worked for a government department whose job it was to slow things down so the people didn't get run over by the government. Any ideas of the title? I think there was a lot of subterfuge between the agents. It's on the edge of my memory.
Comment: What were the sci-fi elements of this novel? When did you read it? How old was it? Was it in English? Where/when was it set? Anything about the plot? *Any* more details you can remember might help someone to identify it!
Comment: Like Frank Herbert's "Bureau of Sabotage" stories? See https://en.wikipedia.org/wiki/Bureau_of_Sabotage
Comment: Certainly not the answer, or even directly related, but the description here reminded me of Jack Vance's short "Dodkin's Job".
Answer: Might this be one of the stories set in Frank Herbert's fictional universe featuring a Bureau of Sabotage? From the Wikipedia article on them:

In Herbert's fiction, sometime in the far future, government becomes
terrifyingly efficient. Red tape no longer exists: laws are conceived
of, passed, funded, and executed within hours, rather than months. The
bureaucratic machinery becomes a juggernaut, rolling over human
concerns and welfare with terrible speed...

There are two novels (Whipping Star, first serialized in Worlds of If in 1970, and The Dosadi Experiment, serialized in Galaxy in 1977), or it might be the short story introducing the concept: "The Tactful Saboteur."
Whipping Star has come up here before, and it was unofficially accepted (via comment) as the answer for a somewhat similar question. See: Novel with teleportation and a progress-delaying bureaucrat?
Comment: The Tactful Sabatoeur. Thanks so much!
Comment: Now I just have to look through a few hundred anthologies in the garage to find it :)


Walmart wrongfully collecting taxes, what can I do?

Question: I purchased a few grocery items and went to pay for them. A couple jars of pickles, a bag of oranges and a bag of apples… when it was time to pay, I used a EBT card and then was told I owed still $4.88… to my surprise, I was charged tax on the apples and it was not covered by EBT… I saw on the receipt I was charged tax on fruit… so I asked management why and their explanation was that it was bagged… well so was the oranges but they were not taxed. Walmart is charging tax on certain food items that qualify as eligible for tax exemption in Florida… I guess I will have to report this to the department of agriculture and the tax office along with family and children services… this is wrong and discouraging healthy foods…
Comment: What is your question?
Comment: The tax is on the apples. Personally I'd ask the store manager; the goal is this understand, and if it really is an error get your money back and get the registers fixed; that all happens faster if you do it locally. You can grumble to state/town agencies at the same time (there is no federal sales tax) if you're feeling vindictive, but their first question is going to be "did you take this up with the store?". And there _can_ be irrational lines drawn in taxes; this could be legit. I can easily see Florida exempting their signature product.
Comment: yes, companies and governments rip people off, more news at 11
Comment: Were you charged the $4.88 on your Visa because you didn't have enough on the EBT card, or were you charged the $4.88 on your Visa because Walmart considered the apples to be non-EBT-eligible? If the latter, that's a more serious problem than the $0.34 tax.
Answer: The apples on your receipt are EBT eligible, per the Walmart online website.
You should not have been charged sales tax, as per the Florida dept. of Revenue guidance.
I don't think it's "fraud" (as you tagged the question), probably something mis-configured in their system. You can report sales tax violations to the Florida dept. of Revenue following the instructions on this site.
FWIW, in California this item is sold for $4.88 (pre-tax, food is tax exempt in CA), which is exactly what you paid. You can verify that by changing the zip code on their site to a California zip (for the Pensacola, FL store it shows $4.54, matching your receipt).
Comment: Don't know, but seems too precise to be a coincidence IMHO.
Comment: @CraigW The pre-/no-tax price in California, $4.88, is exactly the same as the pre-tax price in Florida, $4.54, plus the tax that was charged in Florida, $0.34. So purchasing these apples in California or at this Florida Walmart would cost $4.88 in either place. I think that's what littleadv is getting at.
Comment: What's the relevance of the apples selling for $4.88 in California? Just seems like a coincidence, no?
Comment: A thorough explanation along with how to report this.  It doesn't get any better than that.


use my inputs like input

Question: HI I'm new in Ubuntu but i had a problem I have one audio output and two audio inputs on my computer. But, I have one microphone, stereo reproductors and headphones. In windows Realtek driver, I could simple change the audio input to output, now I'm using Ubuntu. Is there any option to change the input to output and conversely? Thanks
Comment: Can please edit your question and add the ouput of `lspci | grep -i audio` and the output of `lsusb`. Thanks
Answer: I change the output between a audio jack device and a USB device using the "Audio" Program in Ubuntu. It's the same as clicking on the top right audio icon and choosing th last option (audio settings). There is an input tab, which lists my devices and I can easily change the active one.
Since I'm not sure about your setup, but this may help you or someone with a similar problem. It definitely works for me with a usb device which acts as an own sound card.

use my inputs like input


Twitter json count limit?

Question: I was wondering if there is a limit to the number of tweets you can return as json using the api URL? eg. http://api.twitter.com/1/statuses/user_timeline.json?include_entities=true&include_rts=false&screen_name=CocaCola&count=3000
Answer: I think the V1.1 really have the limited.
https://dev.twitter.com/docs/api/1.1/get/statuses/user_timeline
Count(Optional):
Specifies the number of tweets to try and retrieve, up to a maximum of 200 per distinct request. The value of count is best thought of as a limit to the number of tweets to return because suspended or deleted content is removed after the count has been applied. We include retweets in the count, even if include_rts is not supplied. It is recommended you always send include_rts=1 when using this API method.

Twitter json count limit?


Can airliners take off, cruise and land while unpressurized?

Question: I'm wondering if the pressurization of the cabin has a part to play in the structural integrity of the fuselage, the same way an unopened soda bottle is stiffer compared to one that's open.
Comment: DC-3s were airliners, and didn't even have the capability for cabin pressure.
Comment: You are aware that near sea level, where the air plane experiences high loads during take-off and landing, there is no pressure difference to the surrounding air, right? That kindof answers your question, if you think about it. (The soda bottle has a much higher internal pressure than the surrounding air at all times.)
Comment: If leaving the cabin unpressurized is an issue, the airliner just sitting on the ground is a problem.
Comment: Airliners can [still fly with holes in them](https://www.latimes.com/archives/la-xpm-1989-02-24-mn-420-story.html), so even if pressurization plays a part in structural integrity, it's not a *necessary* part.
Comment: @GregHewgill https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243 is an even better example.
Comment: My hunch is that you are talking about jet airliners at 30,000 ft. But airliner is a broad term that can refer to a variety of aircraft, many of which normally fly much lower. In any case, takeoff and land are not issues at all - the pressurization of a typical jet is equivalent to several thousand feet above sea level - once you are below that physical height you would normally be at the "real" pressure. The real question is "cruise".
Comment: If an airliner experienced sudden depressurization at altitude, and then disintegrated during the emergency descent because of immediate structural failure, people would get upset.
Comment: Didn't MH370 flew quite a while after depressurization?
Comment: Why might they not, except if you were Asking about flying at (great) height?
Answer: There is no aircraft limitation on the 737 that requires pressurization to fly.  Realistically, even on O2 the whole time, going very high could be unpleasant.  I think the Air Force limit was FL 250 for routine unpressurized flight (recalling the T-37); when we depressurized the C-130 for high altitude air drops, we had some amount of pre-breathing that we did, and I never dropped anything near, at, or above FL 250.
But all of those are policy limitations, based on the human physiology involved, not the aircraft itself.
In airline life, I've done a maintenance ferry flight at 10,000' unpressurized, which is the highest we can have the cabin without needing to put on O2 masks.  There are probably ways to ferry higher than that if you really had to (crossing the Rockies, for example), but it wouldn't be preferable.  Again, though, that's looking at the human element rather than the jet.
I suspect that the reason that there aren't any limitations as postulated in the OP is that the aircraft itself is sufficiently strong that the extra rigidity of pressurization doesn't add anything necessary.  After all, the aircraft structure has to be able to withstand a sudden depressurization at cruise altitude, along with the ensuing emergency descent down to 14,000'.  When the structure is strong enough to handle all of that, I expect that what's gained by pressurization is just icing on the cake.
Comment: Additionally, aircraft take off and land unpressurized, so the fuselage needs to be strong enough for that anyway.
Comment: And of course most people riding in a C-130 are at their peak - young, physically fit, with military training specifically for that sort of thing.  On a 737, you've potentially got people who are children, elderly, or with any number of physical ailments that would be a problem in an unpressurized flight.
Comment: Actually, they takeoff and land very slightly pressurized, a few hundred feet worth, to allow the pressure to be tapered on and off gently so that passengers don't sense the "bump" in pressure.
Comment: As as aside, sometimes the cause of no pressurization can impose an altitude limitation, say, no pressurization due to two malfunctioning packs might cause an avionics cooling issue at too high an altitude, but that a secondary effect.
Comment: @nexus_2006  Good point - all packs inop may well ground the aircraft. But that's a separate (tho not unrelated) situation. The ferry flight I did was due to a suspect pressurization controller; we at least had good packs, thus adequate cooling.
Comment: With portable oxygen or flight deck crew only (flight deck oxygen has much more capacity than passenger systems) there's no reason a ferry flight with disabled cabin pressure couldn't go to FL 250.
Answer: Yes airliners can fly unpressurised, because pressurisation is not part of the critical load calculations.
The aeroplane fuselage is dimensioned using the critical G-loads from gusts. The largest gust impacts are at:

low altitude (higher air density, ground effect)
low airspeed (gust load is introduced more rapidly into the structure)

Both conditions are at take-off and landing, where the pressure differential is much lower than in cruise.
Answer: Any airliner, or any other airplane for that matter, that falls apart if made to fly unpressurized, does not pass certification. The 'Soda Bottle Effect' does add to the structural rigidity of the fuselage, but this is in no way considered part of the required structural integrity of the airframe. On the contrary, if considered at all, it is to see if it jeopardizes it. Don't beat me up over what specific rule, section or paragraph says so, but I recall the use of pressurized gas as a component of structural integrity in aviation is for obvious reasons categorically prohibited. It would be widely in use if that wasn't so.
Comment: Nobody here will beat you up, but adding a reference would be a nice touch.
Comment: @PeterKämpf I'm not even sure if there is any one specific rule that directly forbids it. I didn't find any satisfactory one and gave up. Either that or I just got lazy. I think it is more like it just never passed because it didn't survive tests. It would be great if it did. Pressurization as a component of structural integrity is what keeps most plants from falling over, so it does work. Filaments filled with compressed gas for building airplanes are being used successfully  in RC planes, so maybe one day,... who knows?
Comment: "the use of pressurized gas as a component of structural integrity in aviation is for obvious reasons categorically prohibited."

Isn't that part of the definition of a blimp?
Comment: @TWL Sort of, but not really. Blimps and helium balloons rely on the lighter than air characteristic of helium, rather than on pressurized gas of any kind. Moreover, they may tend to return in the original shape after being pushed in, but that hardly counts as structural integrity.
Answer: This actually did happen with a Boeing 737 on Helios Airways 522. Due to a bad switch setting and lack of communication between ground and flight crew, the pressurization was disabled. The plane sounded an alarm, but it used the same sound as an alarm that meant something completely different on the ground. The flight crew mistook that alarm for the one that couldn't happen in flight, and therefore ignored it. The plane never pressurized so the internal and external pressures were equal for the whole flight. The flight crew became incapacitated, the passenger oxygen masks dropped, and the plane flew its entire flight plan unpressurized on autopilot, up to entering a holding pattern over its destination. One interesting thing that did happen is that the alarm light for avionics cooling came on. The avionics are air-cooled, and without pressurization there might not be enough air to cool them. Even with the alarm, the avionics including autopilot continued to function.
Unfortunately the crew never woke up and never landed the plane. It eventually ran out of fuel and crashed, killing all aboard, but the plane itself functioned perfectly until it ran out of fuel.
Answer: Because of the cost of flying an empty plane, commercial flights are sometimes undertaken unpressurised, according to a British Airways maintenance engineer I knew (so it's an unverified third-party claim).  They stay below 10,000ft - normal pressure altitude in an airliner is 8000ft based on my own measurements.


Funny recurrence

Question: Could someone help me solve the following recurrence?
$$
T(k) \le 1+\sum_{i=1}^{n_k}T(k_i),
$$
where $n_k\le k$, $k_i\le \frac23 k$ $\forall i = 1, \dots n_k$, and $\sum_{i=1}^{n_k}k_i \le k$.
The intuition behind the problem is that I have an algorithm that takes an instance of size $k$, splits it into $n_k\le k$ pieces each of size at most $\frac23 k$, and solves the problem recursively on each of the instances.
I would like to know the runtime of the algorithm, but the only simplification of the recursion that I can think of is to say, ok, we can have at most $k$ pieces each with size at most $\frac 23k$, what gives the following simplification
$$
T(k) \le 1+kT(\frac23k),
$$
but this clearly cannot happen because we cannot have $O(k)$ pieces each of size $O(k)$, since then the size of the input instance must be $O(k^2)$.
Comment: Also we don't know exactly which piece has what size, we only know that each is at most $\frac 23$ of the input instance.
Answer: You may prove a polynomial upper bound by induction. At first, denote $f(k)=T(k)+M$ for certain large $M$, this $f$ satisfies the inequality $f(k)\leqslant c\sum f(k_i) $ for some $c>0 $. Assume that we know the inequality $f(x) \leqslant Q x^a$ for the constants $Q>0, a>1$. Then the maximal value of $\sum k_i^a$ under your restrictions is $(2k/3)^a+(k/3)^a$ and if $c(2^a+1)/3^a<1 $,  induction works.
Comment: Also, if $AC<1$ a linear bound holds.
Comment: Hi, thanks for the answer, actually I just realized that that the constants are not important form me. What matters is to give an upper bound on the worst partitioning of a number $k$  under the restrictions.

Funny recurrence


Deutschlandticket to Dutch border stations — how to pass the ticket gates?

Question: The Deutschlandticket (German ticket valid on almost all local and regional transportation in Germany) is valid for travel to the Dutch border stations of Venlo, Enschede, or Arnhem (source).  In The Netherlands, train stations have ticket gates where tickets need to be scanned to get out.  How does this work for travel with the Deutschlandticket?  I have a chip card from Frankfurt am Main (VGF/RMV) and I would be surprised if this were recognised by the Dutch ticket gates.
Comment: At least at Nijmegen, the answer is that there are two sets of ticket gates - one for dutch trains, one for german.
Comment: So in fact, only a minority of all Dutch railway stations have gates (but obviously all major ones do). The others simple have poles to check in and out but nothing physically preventing you from walking to the platform.
Answer: It's been awhile since I have been in this part of the country but Venlo is not on the list of stations with closed gates so you can presumably ignore the whole thing and just walk right out. IIRC correctly, that's also the way things stand in, e.g., Hengelo.
Arnhem and Enschede on the other hand are on the list. This leaves a few options:

Check in on the platform with an OV-chipkaart and then use that card to check out. It needs to have credit available but you won't be charged. I am doing this all the time when alighting from the Thalys in Amsterdam. Not all stations in the Netherlands have check-in poles on the platform but both Arnhem and Enschede welcome trains from multiple operators so it should be possible in this case (the poles are there to facilitate transfers between different train operators).
Check in on the platform with a debit or credit card and then immediately check out with that same card. I haven't personally tried it but as suggested by Berend in the comments, you should be able to do this little check-in check-out dance with a credit card as well.
Get a barcode from someone (DB?). NS has a procedure to request a barcode if you have a railcard. It doesn't exactly cover your situation but it's possible DB is also able to generate similar barcodes. Note that barcodes (or QR or Aztec code) can only be read by gates with an optical reader. Most gates don't have one but each exit should have at least one gate you can use, see this answer for pictures.
NS also issues keycards to open the gates without a ticket but I don't think it applies here and unlike a barcode you could print at home or have your phone, a keycard needs to be shipped or picked up at a specific location, which doesn't seem very practical in your situation. As mentioned by Tor-Einar Jarnbjo in the comments, the train guard may however be able to provide one.
Call for help. Each row of gates, even small ones at unmanned stations, should have a way to call for help. If all else fail, you can call and ask them to open a gate remotely.
As suggested by @JeroenHoek, tail someone through the gate, possibly after asking them. The gates sometimes beep but are really not that quick to close down (certainly compared to the gates in transit systems like the Paris metro) and won't close as long as the sensors detect something inside the gate.
Comment: Now that OVpay is live, I think you could even use your credit card, instead of an OV-chipkaart, right?
Comment: @Tor-EinarJarnbjo I have never seen one, they may have a barcode or QR-like code (not calling it a QR code to avoid gerrit's wrath)? That was always NS preferred solution and the reason there should be at least one gate with an optical reader per exit in a station.
Comment: @Relaxed I found it now deeply hidden in the information published by VRR. If you travel from Germany to e.g. Arnhem with a ticket lacking a suitable bar code, the train conductor will give you a KeyCard allowing you to exit through the gates. It sounds as if that also applies for travellers with a Deutschlandticket.
Comment: Also before the Deutschlandticket, it was possible to travel to Arnhem and Enschede with tickets issued by the German transport authority VRR. Was it possible to use these tickets to get through the gates when leaving the station?
Comment: @Berend Good point! I think it should work.
Comment: @Tor-EinarJarnbjo Good find, will add a note about that!
Answer: According to the Dutch Wikipedia article on Arnhem Centraal:

Arnhem Centraal is een station met poortjes. Het station is een gemeenschappelijk poortjesgebied voor de verschillende vervoerders op het station; in de stationstunnel en bij de ingang Sonsbeekzijde zijn poortjes te vinden van NS en poortjes voor Arriva en Breng. Voor overstappende reizigers zijn op de perrons paaltjes te vinden, waar reizigers tussen de verschillende vervoerders kunnen omchecken. Sinds 2016 zijn de poortjes gesloten, reizigers met internationale vervoersbewijzen zonder QR-code kunnen zich wenden tot het in het station aanwezige servicepersoneel.

My translation:

Arnhem Centraal is a station with fare-control gates.  The station is a common fare-control area for the various companies serving the station; there are gates for NS, Arriva, and Breng in the station tunnel and at the entrance on the Sonsbeek side.  For transferring passengers there are poles on the platforms where passengers can switch between different companies.  The gates have been in operation since 2016; travelers with international tickets having no QR code can seek assistance from the service personnel in the station.
Comment: @gerrit I've never heard of Aztec codes and I suspect that majority of people also hasn't, and looking at it I would think it's a QR code. It could very well be an Aztec code but for simplicity's sake they call it QR code because people are familiar with that term and couldn't tell the difference
Comment: @gerrit - I never tried _many_ barcode readers, I have one on my phone that I'm happy with but it reads Aztec just fine.
Comment: BARcode = a big BAR made of little BARs. QR code = a big sQuaRe made of little sQuaRes. That's a good enough definition for 99% of the public who cannot tell an EAN code from a Databar code, nor a QR code from a Data Matrix code from an Aztec code.
Comment: Huh, interesting that it refers to QR codes. AFAIK, [Aztec codes](https://en.wikipedia.org/wiki/Aztec_Code#Usage) are much more common than QR codes in transportation, including on Dutch and German digital ticket. In the past, I've used German tickets with an Aztec code (without a QR code) without problems.
Comment: @Ivo They would find out if they ever try to use their phones' QR-code reader to read it and fail. And at least the DB ones look different from QC codes.
Answer: Travelling with anything but the Dutch OV Chipkaart on the Dutch rail network on stations with automated gates has always been an afterthought (it comes across as if we Dutch actively hate tourists). Most printable international tickets have QR codes which work on those gates which have a scanner window rather than just a NFC scanner. Even the nighttrain to Vienna does this correctly, regardless of where you actually bought the ticket.
Of course that won't help you if you have a valid ticket, but no QR code.
All answers above are fine, but you in case you do not feel like wasting your time for an oversight by the people who decided that not having any manned gates on an international train station was reasonable, you might simply opt for the Dutch way:
Just tailgate someone exiting the station through a gate.
The gate will obnoxiously beep at you, but they do that all the time because:

People have strollers or wheelchairs (beep beep beep beep)
People have a digital ticket with a QR printed and ready, but for multiple passengers (ticket holder opens the gate once, all pass through single file, beep beep beep beep)
Slow children/elderly (beep beep beep beep)
People pass through them with a bicycle (beep beep beep beep)

No one will bat an eyelid, and if someone does approach you, just show your valid ticket and plead ignorance. You are not actually doing anything illegal as long as you don't jump over the gates and have a valid ticket, despite the NS claiming this is.
You don't have to do this of course, and many people would feel uncomfortable bending the rules like this; feel free to wander the station hall looking for staff available to help (good luck during rush hour). Just know that you can if it turns out to be the more convenient option.
Comment: @gerrit That doesn't matter, since nearly anyone will refer to those as QR codes. And there would never be a need to scan those with your phone anyway. At least not if you are trying to open a gate.
Comment: @gerrit Nobody cares, what is meant here is "two dimensional matrix barcode". The difference between QR codes and Aztec codes is irrelevant to this entire Q&A and simply calling it a "QR-code" is probably the most effective way to explain what is meant. Anything else, you would need to add a parenthesis like "this thing that looks like a QR-code" to make sure people can understand the answer without having to look it up.
Comment: @gerrit I just explained why that doesn't work. You will note that I used the word "barcode" in my own answer from the get go but pretending that when people write "QR code" they mean to refer to that specific technical standard and contrast it with Aztec codes or any other type of two dimensional barcodes is actively misconstruing their intent and just plain dumb.
Comment: I think international tickets (and other digital tickets) have Aztec codes, not QR codes. Try reading one with your favourite QR code reader and you will fail.
Comment: @Relaxed Then call it a two-dimensional matrix barcode...
Answer: A few years ago I had the same problem when travelling with an Interrail Pass: I got stuck inside a Dutch railway station. After some wandering around I managed to find an NS employee who helped me go out and told me to go to the ticket office, show them my Interrail Pass and ask for a so-called KeyCard for opening the gates. I did so and got a credit-card-sized card that opened the gates at all stations.
Somebody posted a photo of one to a social media site, so you can take a look at it there. You may be able to request one here, but the description provided on this site does not match our use-case:

Passing through the gates without travelling
The KeyCard is intended for affiliated/other/international
transporters, organisations, and companies that need a barcode with
unique specifications for a shorter or longer period. The KeyCard can
also be used for a specific inter-neighbourhood solution.
Comment: It was probably an [Aztec code](https://en.wikipedia.org/wiki/Aztec_Code#Usage) rather than a QR code.
Comment: Good point, @gerrit, although I just removed that part since I found out its official name, and now I just refer to it as a KeyCard.
Comment: The KeyCard is interesting! Sadly, I'm too late for my upcoming travel, but I'll find a solution according to the other answers somehow.
Answer: Not directly related to the Deutschland-Ticket, but I found some likely relevant information in the information published by VRR (the transport authority in the neighbouring German region) regarding travel to the Netherlands. Not only the Deutschland-Ticket, but also other tickets issued by VRR are valid for travel to e.g. Arnhem, but may also lack a bar code required to get through the gates in Arnhem:

Reizigers vanuit Duitsland met een geldig ticket, maar die niet over
een barcode of chipkaart beschikken voor het openen van de poorten in
Arnhem, ontvangen tijdens de rit van de conducteur een zogeheten
KeyCard. De KeyCard kan na het eerste gebruik nog achtmaal binnen drie
maanden worden gebruikt.

Or translated:

Travelers from Germany with a valid ticket, which does not have a
barcode or chip to open the gates in Arnhem, will receive a so called
KeyCard from the conductor during the journey. After the first use,
the KeyCard can be used eight times within the next three months.

So if you travel with a Deutschland-Ticket to Arnhem, the train conductor should provide you with the KeyCard required to leave the station.
Comment: I have recently taken several such trains and we were indeed given keycards shortly before reaching the respective stops in the netherlands. What happened was that a ticket inspector walked through the train and offered these keycards to any passenger.
Comment: so you need to go see the conductor while you're still in the train?
Answer: In Enschede, the issue is sidestepped by having the track for the trains to/from Germany outside of the faregated area.
<code>-------4a-:----:-4b----------> Germany
# platform ##|############
-------3--: #|# station
-------2--: #|# building
# platform ##|#
-------1--: #|##
</code>
: denotes bumpers, | denotes the faregates. If you prefer a less crude picture, someone has posted a 360° picture to Google Maps: https://maps.app.goo.gl/reWCirsYFMmGGZUS7  It didn't change since then, except that I don't remember the big yellow standup sign about DB tickets from my visit a few weeks ago.


Garuda [Big Thiruvadi] and Hanuman [Small Thiruvadi]

Question: Garuda the king of birds is the vahana of Sriman Narayana and his consort Goddess Lakshmi. He carries them on their shoulder and flies from one place to another. He will be on the skies hence known as Big Thiruvadi. Likewise Hanuman king of vanaras carry Lord Rama, Sita and Lakshmna on his shoulders from one place to other in land. Hence he is known as Small Thiruvadi.
Any mythological evidence for this? If so in which purana?
Comment: @Rickross Thiruvadi means the feet of  God.
Comment: Can you make the question more clear with precise title? Btw, [this discussion](http://www.ramanuja.org/sv/bhakti/archives/jan2001/0102.html) from ramanuja.org looks related
Comment: What is thiruvadi?
Comment: @Pandya This is the shortest title I arrived after various thought process. Thiruvadi means feet of God.
Answer: Garudazhwar is known as Periya Thiruvadi, since he is the Vahanam (vehicle) of Sriman Narayana and also all of his incarnations such as Krishna. But Hanuman is known as Siriya Thiruvadi since he is the vehicle/devotee of only one of the incarnations of Vishnu, namely Rama.
This practice of calling Garuda as Periya Thiruvadi and Hanuman as Siriya Thiruvadi is followed in the Srivaishnava tradition. Hence, there is no Puranic reference for this. Also, it is important to note that these terms are in Tamil, and Puranas are written in Sanskrit.
Comment: @ParthasarathyRaghavan I am saying that there is no citation in Sanskrit..
Comment: @ram Do not bring languages. In puranas there might be a instance of mentioning about the Thiruvadis be it in Sanskrit or French or Tulu. Answer is inappropriate coz Hinduism is a ocean. You have to explore.
Comment: @ParthasarathyRaghavan What I am saying is that they may be mentioned in Sanskrit, but not in Tamil..
Comment: Of course, Where is the citation from Sanskrit? Your  answer is my question.
Comment: @Ram Then put your answer in comment. If the answer is given then citation to be quoted.
Comment: @ParthasarathyRaghavan There is no citation as the terms Periya Thiruvadi and Siriya Thiruvadi are NOT mentioned in the Puranas.


Iraqi Dinars. Bad Investment, or Worst Investment?

Question: Some family members are getting excited about investing in Iraqi Dinars. I'm pretty sure it's not a great idea. What are the best online resources for or against this idea?
Comment: Just a nit pick - It is speculation, not investing.
Comment: I have concerns about this question being no different than a stock tips question.  I would generalize the question to currency investing and use the Iragi Dinar as a specific example.
Comment: That is some speculation. If the oil starts flowing then money money money or else if it remains like it is now, forget about your investment.
Answer: Iraq is a US vassal/puppet state. I'm not sure what 500 South Vietnamese Dong were worth in 1972, but today the paper currency is worth $10 in mint condition.
I'd suggest blackjack or craps as an alternate "investment".
Answer: Currency, like gold and other commodities, isn't really much of an investment at all. It doesn't actually generate any return. Its value might fluctuate at a different rate than that of the US dollar or Euro, but that's about it. It might have a place as a very small slice of a basket of global currencies, but most US / European households don't actually need that sort of basket; it's really more of a risk-management strategy than an investment strategy and it doesn't really reflect the risks faced by an ordinary family in the US (or Europe or similar).
Investments shouldn't generally be particularly "exciting". Generally, "exciting" opportunities mean that you're speculating on the market, not really investing in it. If you have a few thousand dollars you don't need and don't mind losing, you can make some good money speculating some of the time, but you can also just lose it all too. (Maybe there's a little room for excitement if you find amazing deals on ordinary investments at the very bottom of a stock market crash when decent, solid companies are on sale much cheaper than they ordinarily are.)
Comment: Postscript. Historical Iraqi inflation. http://www.indexmundi.com/iraq/inflation_rate_%28consumer_prices%29.html
Answer: Once a currency loses value, it never regains it. Period. Granted there have been short term periods of deflation, as well as periods where, due to relative value fluctuation, a currency may temporarily gain value against the U.S. dollar (or Euro, Franc, whatever) but the prospect of a currency that's lost 99.99% of its value will reclaim any of that value is an impossibility.
Currency is paper. It's not stock. It's not a hard commodity. It has no intrinsic value, and no government in history has ever been motivated to "re-value" its currency. Mind you, there have been plenty of "reverse splits" where a government will knock off the extraneous zeroes to make handling units of the currency more practical.


How many fresh peaches are equivalent to 20 ounces of frozen peaches?

Question: I have fresh ripe peaches and plan to make a cobbler. The recipe calls for 20 ounces of frozen sliced peaches, how many fresh (medium sized) should I use?
Comment: In a cobbler, I'm not sure that you need to super accurate, but why wouldn't you use 20 ounces (or round up to the nearest whole peach)?  Do you have a scale? Or maybe your question is "how much does a medium sized peach (minus pit) weigh?
Comment: I'd say it's 1:1 (i.e. 20 for 20), assuming the frozen peaches are frozen from fresh, then there shouldn't be any water loss that might complicate things.
Answer: If the problem is that you don't have a scale in your kitchen, (which for some reason is common in the USA, I grew up in a house like that) then get a quart measuring cup and hack up fresh peaches until you hit (or exceed, I agree with the comment) 2-1/2 cups - because 20 ounces by weight of frozen peaches is pretty near to 20 ounces by volume of fresh peaches and juice, if cut and packed so there's not much air space. If leaving air space it might be full quart of less packed down/cut up peaches.
Also, put a kitchen scale on your gift list for whatever gift giving occasions (including gifting yourself) might be coming up, and correct that situation.
If you have a scale, remove pits and weigh 20 ounces of pitted peaches.
How many medium peaches gets caught up in "what's a medium peach" but seems to be 4 according to one definition of "medium" (5.3 ounces, I'm going to guesstimate the pit as 0.3 so it works out, and I'd choose 5 to be sure there was plenty, since @mosjafj is correct in the comments. And pits might be heavier than that.)
Comment: You can get perfectly serviceable kitchen scales for about $10 on eBay (mine are as good as the ones I had before cost 3x that, except for being a little small so the display hides under big pans).  I'd hesitate to recommend just spending money, but honestly, they're worth having
Comment: I absolutely suggest, without hesitation, buying or getting a suitable scale, but that doesn't help with making a peach cobbler *right now.*


Makkas Dam throughout the whole world?

Question: Someone told me in the name of a Talmid Chacham that Makkas Dam was not just in Mitzrayim, but was throughout the whole world, similar to the water splitting everywhere in the world. However, I looked throughout many Midrashim and commentators on the pesukim and couldn't find anything. Is there a source for such an idea? (It is interesting to note that Mitzrayim didn't go to other neighboring nations for water rather than buy it for exorbitant prices from their former slaves)
Comment: wouldn't that go against pasuk 24?
Answer: I did some thorough research and I wasn't able to find a single person who claims that Makkas Dam took place around the world as well as in Mitzrayim.
As to your insight on the fact that the Egyptians didn't go to neighboring cities for water, rather they bought them from their previous Jewish slaves, is assuming one of the many approaches found in the Medrash(1), yet there are other approaches that held that they the Egyptians drank mayim meluchim - salty water(2), or that that they manually dug wells around the Nile and found regular water there(3).
Even according to the opinion that they purchased the water from their previous Jewish slaves, it doesn't necessitate the fact that it was a result of the neighboring cities being stricken with Makkas Dam as well, for there are other approaches who held that that the Egyptians drank other forms of liquid such as wine during this Makka(4), or that the water turned into blood for a short duration and then turned back into water(the Egyptians couldn't drink it because when the water turned into blood the fish died and contaminated the water.) (5).
I gained the vast majority of my knowledge on this subject from an incredible article written by Boaz Spiegel of Bar Ilan University who discussed this topic in immense depth.
1)Medrash Tanchuma(Buber), Va'era, 14.
2)Mishnas Rebbi Eliezer, chpt. 19, see as well Seder Eliyahu Rabbah, chpt. 8.
3)Rebbi Yehuda in Shemos Rabbah, 9, 11.
4)Medrash Sechel Tov, 7, 23.
5)Bechor Shor
Comment: Interesting finds - thank you for sharing! There is a Midrash Lekach Tov (Shemos 7:19) which says all the water which was brought into Mitzrayim turned to blood:  לרבות אפילו המים שהיו מביאין ממקום אחר.

Makkas Dam throughout the whole world?


What kind of Tzitzit should a convert wear?

Question: I am working on an Orthodox conversion and starting to take on mitzvah's I have been looking at getting tzitzits and as i don't have a family background i see they come in different types such as Chabad, Sefardi, Ashkenaz and I've seen Avodas Yad. also whether I should be wearing wool or cotton. I am not sure which style is appropriate for me as a convert. Any guidance is appreciated.
Comment: Typically, when converting, you adopt the minhagim of the community that converts you. So if they tie their tzitzit ashkenaz, then you should to.

Personally, I like wearing cotton.
Comment: Sounds like a question for a Rabbi.
Answer: Caveat, this answer is mostly what I've gathered from the communities I live in as well as discussion with my rabbi.
This all depends on the community you're converting into and the customs of your rabbi. If you choose to adopt Ashkenazi customs, you should wear tzitzit which are tied according to the Ashkenazi practice. The same formula goes for if you decide to become Sephardi or Chabad (most other Chassidim tie Ashkenaz as far as I've seen). In regards to the garment, wool is viewed as biblically mandated by all sources, although cotton has no such widespread appeal. I personally wear a wool garment with thick tzitzit tied according to the opinion of the Ba'alei Tosafot (techeilet).
Another point on vocabulary: "עבודת יד" (Avodat yad/avodas yad) means that the strings are completely handspun, they can be either thin, medium, or thick.
Another issue, although not one to get into immediately is whether your adoptive community accepts techeilet, as it is both an expensive proposition and a more complex issue when it comes to tying.
Answer: May HaShem bless you as you seek to come under the wings of His shekhinah!
In answer to your question(s):
According to halakhah, if one is not wearing tekheleth in his ssissiyyoth then all that is required is the correct amount of kasher strings and at least three windings (and there is a LOT of leeway in the halakhah for doing more windings, knots, etc.).
[See Rambam, Mishneh Torah, Hilkhoth Ssissith 1:9]
If you are using tekheleth then you need to make a decision as to which method you will abide by - and your decision need nothing to do with "custom" since neither Ashkenazim, Sefaradim, Hasidim, nor Yemenite Jews ever possessed tekheleth when their traditions developed.
There are about four methods that seek to be authentic to Hazal, the rest are relatively late and based on doubts regarding actual requirements, ignorance of how they should be tied according to the various beraytoth, combinations of differing (and sometimes opposing) halakhic views, and latter-day derivations and contrivances from the "kabbalah."
The four shitoth that I am referring to are:
[A] Ra'avadh (which is really the shitah of Rav Natronai Gaon)
[B] Rav Natronai Gaon (in his own words)
[C] Rav Amram Gaon (from his siddur)
[D] Rambam (which is a variation on the shitah of Rav Amram Gaon)
[See instructions on how to tie these on www.tekhelet.com]
However, me-iqqar ha-din (from the strict standpoint of the law) any of the extant methods of tying with tekheleth are kasher and one may make a blessing on them, but one should be aware of the relatively late and contrived nature of most of them.
All of this being said, any style of ssissiyyoth that personally suits you and accords with the halakhah will do.
The only practical note I can offer outside of halakhic considerations is that a great many batei din will refuse to convert - or will make the process much more difficult - for candidates who "choose for themselves" so it is best to just simply ask your sponsoring rabbi which one to wear. Doing such to prospective converts is petty and without legal basis - and is almost certainly a crime in the eyes of the halakhah - but the unfortunate fact is that things like this happen all the time. So, just direct these questions toward them and you should be fine. After you convert they no longer can dictate such things (read "micromanage") and you will be free to express your Jewish faith in the halakhic manner you so choose. Until such a time, my sincere advice is to play it safe.
As regards the material (e.g. cotton or wool), the ssissith should either be wool or from the same material as the garment itself (cf. MT, Hilkhoth Ssissith 1:1, 3:5-7). The only exception to this rule according to the halakhah is that no tekheleth should be placed on the ssissiyyoth of a linen garment, and this is by force of rabbinic decree (Ibid. 3:7).
Lastly, wear a talith qatan that is comfortable for you, regardless of the type or style of the ssissith that you end up attaching to it. Don't buy into the idea that a wool garment is the more religious or "frum" choice - it's not. If you want wool, then by all means buy a wool garment for daily use, but if you find it to be uncomfortable (as most do) then wear something made of cotton or mesh. Remember that while the fringes are certainly of spiritual significance, the garment mentioned in the Torah is of a practical one. We are not Mormons sporting magic underwear, we are Jews who attach a decorative fringe to the corners of our garments - as God commands us - which reminds us of our duties as part of the holy nation.
Hope this helps. Kol tuv.
Comment: I don't see anything there about a difference between What R Natronai Gaon said and how the Raavad interpreted him.
Comment: It's slight, but it's there. What the Raavadh writes in his *hasaghoth* differs slightly from RNG in his *teshuvoth*. A good explanation is on tekhelet.com regarding this. Check it out. Kol tuv.
Comment: Can you link me to a more specific page about that? Perhaps they have an article about R Natronai's responsum?
Comment: http://tekhelet.com/he/raavad-words/
Comment: It ends up being a matter of one section being all white versus being another section of *hulyoth*. Like I said, it is very subtle, but there is a slight difference. Enjoy. Kol tuv.
Comment: The opinion of the Ba'alei Tosafot is at least as old as the *Yad*, so it should also be mentioned (this is my shittah, so I give it preferential treatment)
Comment: @user3342 not sure what you mean, the texts are identical, and I bet the teshuva is just copied from the hasaga.
Answer: which ever specific minhag you go by they should be wool as other ones are questionable whether they are considered a garment that require tzitzis. Avodas yad could be any minhag also, it justmeans that the strings were made by hand rather than by machine.
It's important to have a mashpia (mentor) that can help you decide your minhagim. Additionally minhagim are not just a specific way one does something within Judaism but are part of a specific pathway in serving G-d (a derech). It would be advisable  to understand that and how you will be proceeding before completing your gerus.
I strongly recommend speaking to the Rabbi who is guiding you in the process before you get to the step of meeting with the bes din.
wishing you much hatzlacha
Comment: Actually, everyone agrees that non-wool garments are obligated in tzitzis.


In thermodynamics what does it mean that a system is taken through a series of small steps?

Question: I'm struggling to understand this concept of reversible process as a transformation from a initial state i ( generic ) to a final state f, but done through small changes/steps.
What does it mean that the system is always in equilibrium with itself if the changes are very small? Wouldn't it be the same for "big" changes?
Comment: think of cold water taken to the boiling point. Heated on the kitchen stoveon low, it will come slowly to boil with no turbulence, because it goes with a small heat inputs  to higher and higher temperatures up to to the boiling point turbulance, where there is no longer equilibrium. If the heat supplied is very high, large change,  the water will start boiling in parts of the sample while parts of it will still be below boiling point.
Answer: Thermodynamics applies to a system that is in equilibrium (there is a separate subject of non-equilibrium thermodynamics). That is quantities like pressure, entropy, free energy etc are only well defined for a system that is in equilibrium.
The problem is that if a system is at equilibrium then it isn't changing because by definition equilibrium means the system is in a steady state i.e. not changing with time.
So we have a problem because:

if a system is in equilibrium it can't change
if it isn't in equilibrium then our usual thermodynamic laws don't apply.

There is a contradiction here, so how can we analyse systems that change with time?
The solution is that provided the change to the system is slow the system will never be very far from equilibrium. Suppose we change the volume by a very small amount. This will shift the system out of equilibrium, but because the change is slow the system will come back into equilibrium very quickly. So quickly, in fact, that to a very good approximation we can treat the system as always having been in equilibrium.
And this is what we mean when we talk about a reversible process being made up of a series of infinitesimal steps. We imagine some change, e.g. increasing the volume, as being made up of a sum of tiny changes, and each of those tiny changes takes place slowly enough that the system quickly equilibrates again. So our system remains very close to equilibrium all the way through the change.
Answer: Thermodynamics of equilibrium is simpler to deal with than its non-equilibrium counterpart, so considering quasi-static processes is useful, since that allows us to use the thermodynamics of equilibrium also when (slow) change takes place.
If changes are fast, even basic concepts can fail to apply. For instance, when the valve between a container with gas and an evacuated one is open, pressure is not defined during the sudden process of expansion. That's a strong statement: it means that it doesn't make sense to attribute a pressure to the system during this process. As a consequence, a line connecting the initial ($i$) and final ($f$) states in, e.g., a PV plot cannot be drawn, because the system didn't go through states of this space between $i$ and $f$, which obviously prevents you from doing many of the usual calculations.
So, when possible, it's often helpful to approximate a given transformation by a quasi-static one, which is done by considering it took place at small steps.
Answer: If you apply a sudden big change to a gas, the ideal gas law (or other equation of state) no longer describes the relationship between pressure, volume, and temperature globally.  For one thing, the pressure and temperature are no longer spatially uniform within the gas (as pressure waves and temperature waves are traveling through the gas). So what value do you use for the pressure in calculating the work? Secondly, there are viscous forces present within the gas (which are not significant when the gas is deforming slowly), such that the forces acting on the boundary of the gas (where work is being done) depend not only on the volume, but also on the rate of change of volume.
It is still possible to describe the behavior of the gas, the forces at the boundary, and the work done if one solves the partial differential equations for heat and momentum transfer (Navier Stokes equation and differential thermal energy balance) and one assumes that, locally, the conditions satisfy the equation of state.  But this is typically beyond what thermodynamics alone can handle, and requires the use of computational fluid dynamics (CFD).  All these complexities go away however if the deformation of the gas is slow (i.e., involves small changes).


XM Cloud Sitecore Information BE

Question: not needed, please delete it thanks . asdasdasdasdsadasdsadasd
Answer: I'm a .Net Backend developer too, I will share my experience in an XM Cloud project.
Definitely, you have to expand your knowledge and learn the basics of React and NextJS, hooks, and TypeScript to start working with the NextJs Starter you mentioned.
In my experience, a Frontend fellow gives me the HTML and all the styling, animations, and pretty CSS classes to make the user experience great, and we have to integrate in .tsx components that will be called in a JSON Rendering in the CMS, similar as we had before with View or Controller renderings.
As BE, if apply for your company's role, you still have to create the templates, renderings, placeholders, layouts, assign data sources, create APIs, create GraphQL queries, and of course, retrieve the data from the content items to our components.
On Github, there's the base branch of the Starter code with examples on how to work with components, here's the link:
https://github.com/sitecorelabs/xmcloud-foundation-head
And in my blog https://sitecoretek.wordpress.com/ you can find some posts that will help you and save time, for example, the initial setup of the project, working with placeholders, and work with GraphQL locally.
Hope this finds you helpful, and trust me, is a new very exciting world to work with XM Cloud and headless.
Answer: Just to add some more context, depending on your Role on the project, as a backend developer:

Having some knowledge about nextJs/react is a plus
Having enough background about docker (for your local setup)
Understanding the deployment and xmcloud deploy app
Having knowledge about the Experience Edge
Having good knowledge of Sitecore SXA and its architecture (Headless variant for xmcloud)
Having good knowledge about the Sitecore CLI and Serialization and IAR deployment
Having good knowledge about graphql query / content resolvers
Understanding the headless architecture and the changes in xmCloud (ex. publishing)
If you are using Vercel, of course, you need to have knowledge about the Vercel and its deployment

If you want to have a starting point please check the Getting started with xmcloud documentation, there are a few videos on YouTube.
You can find some information here: https://www.ashournia.com/, I recommend checking the posts about publishing and workflows.

XM Cloud Sitecore Information BE


How do I use the having clause on an aggregate in a complex group by and join query in LINQ

Question: I have reviewed a lot of the questions and answers here but cant seem to find what I need.
I have the following sql below which I am having real trouble getting into a LINQ statement.
The specific issue is that for one of the fields I am using a CASE statement both in the select and
has part of the HAVING clause. Various reasons why i needed to do this but I cant seem to reproduce it in
LINQ.
Here is the sql:
select Count (DetailID) as MonthCount , StoreID, DetailID, SUM(Amount ) as AnnualAmount, PAYear, MIN(CASE when ExportFlag = 'SUCCESS' then 1 when ExportFlag is NULL or  ExportFlag = '' then 0 else - 1 end) as ExpFlag
from Input_Financials
inner join DestinationDetail cdd on cdd .ID = Financials.DetailID
group by StoreID, DetailID, PAYear
Having MIN (CASE when ExportFlag = 'SUCCESS' then 1 when ExportFlag is NULL then 0 else -1 end ) = 0
and Count (*) >= 1
order by PAYear

This was my best attempt linq statment but you will notice that I dont have the equivalent
of the having clause which aggregates the ExportFlag value (which is very important)
   var query =
               from inf in inputActs
               join cgrdets in cgrDetails on inf.DestinationDetailID equals cgrdets.ID
               let export = (inf.ExportFlag == "SUCCESS" ? 2:
                             inf.ExportFlag == "ERROR" ? 1:
                             inf.ExportFlag == null ? 0: 99)
               group inf by new {export, inf.StoreID, inf.DestinationDetailID,inf.PAYr } into g
               where g.Key.export == 0
               select new { MonthCount = g.Count(), g.Key.StoreID, g.Key.PAYr, Amount = g.Sum(inf=>inf.Amount) };

By the way - please ignore some minor discrepancies you may find in naming of fields between these two - its just probably because i renamed some quickly for the sake of this question.
Comment: A `HAVING` in SQL would just be a `Where` that you call after the `GroupBy` in LINQ...
Answer: It looks like this is what you want:
where g.All(item => item.ExportFlag == "SUCCESS" || item.ExportFlag == null)


How can I achieve a Quartz look using concrete for a bar top?

Question: I want to make my own concrete bar top but I would like it to have a bit of a sparkle like quartz has. Any suggestions?
Answer: It's called terazzo:

The basic process is:

add your 'sparkle' substance as aggregate (glass is a typical option)
pour concrete
after concrete sets, you use a diamond grinder to expose the top layer of aggregate
Answer: It's all in the aggregate. There are a lot of options depending on the look you're going for. Abalone shell is popular, and monochromatic glass chips could work well too. What you do is add a lot of these aggregates to your concrete mix (appropriately colored, and including performance-enhancing additives such as metakaolin or ground granulated blast furnace slag). Then you raise the aggregate by floating the surface while it's still wet. Once it's dry and hard and at least a week old (preferably a month old), you grind the surface down a millimeter or two to expose more of the aggregate. Then polish and seal with sodium silicate and bob's your uncle.
Comment: Never heard ["bob's your uncle"](https://en.wikipedia.org/wiki/Bob's_your_uncle)... Thanks for that.
Answer: You can add white rock on the surface of your cement & tamp it in then finish this will give some color.
Exposed aggregate uses this technique if they want white, black brown rock not just plain cement. Bags of colored rock can be found at many home improvement stores.


Naive questions on AdS/CFT dictionary and alternatives?

Question: I'm starting to become curious about AdS/CFT since hearing that condensed matter theorists use it as a 'dictionary' to find gravity duals of things from condensed matter physics. How exactly does this dictionary work?
Also, are there other promising theories that link gravity in bulk to a conformal field theory at the boundary, just like AdS/CFT? And could the same dictironary be used there?
Comment: AdS/CFT is a framework that connects a class of gravitational theories (that are all asymptotically AdS) to a class of quantum field theories in one lower dimension.
Answer: Not just condensed matter people, but also the folks doing high energy physics. And as of your question of linking a theory of quantum gravity to a CFT (not on "the" boundary in the conventional sense since the boundary for AdS/CFT was very convenient for a lot of reasons, mainly that in the sense of holographic entanglement entropy you can make a bulk-boundary duality from a minimal spacelike surface joining the boundary points), this is simply what holography is, relating a bulk quantum gravity theory in $D$ dimensions to a boundary CFT on a $D-1$ boundary. For de Sitter, this is $\mathcal{I}^{\pm }$ (although the CFT lives on only one large $S^{D}$) naturally. However, this has several complications, like complex-valued entanglement entropy due to a non-unitary CFT, density matrices being transition matrices, no proper "nice" idea of subregion duality, etc. But there is static patch holography, where the pode-antipode system is related to stretched horizon degrees of freedom in the static patch picture. And so on. The point is, there are other examples of dualities, but they are not quite as convenient as AdS/CFT. The bottom-line therefore, is, there are, but at the cost of simplicity. This is an exciting prospect, but it is much messier than AdS/CFT.


What percent of fuel is consumed in powering the turbopumps?

Question: The RD-170 consumes 5,300 lbs of fuel per second, including oxidizer. The turbopump produces 230,000 hp. If one assumes that roughly 1 lb of fuel is required to generate 1 lb of thrust (obviously this varies considerably), not including oxidizer. Assuming an oxidizer to fuel ratio of 3, then 3% of total fuel is used to power the turbopump. I realize there are more variables involved, but to get a rough guess, what would be the best path forward to estimate this number?
Comment: Hi, user27128, and welcome to Stack Exchange. Could you please edit your question to clarify what you're trying to ask? The way I read it, it seems to be something like "if the turbopumps could be magically driven without burning any fuel, how much less fuel and oxidizer would the RD-170 consume?" — which kind of ignores the fact that the RD-170 engine uses a [staged combustion cycle](https://en.wikipedia.org/wiki/Staged_combustion_cycle) where the combustion products and excess oxidizer used to drive the turbopumps are eventually fed into the main combustion chamber and out the nozzle anyway.
Comment: I fail to understand if you are asking about specific impulse during startup phase (as you seem to speak of consume fuel vs thrust) or the amount of fuel consumed during startup phase vs total of fuel consumed during power flight. You should clarify that point.
Answer: Your question is a bit confusing because of your use of "fuel" to sometimes mean "fuel" and sometimes mean "propellants". Based on my interpretation of the question here is an answer.
The RD-170 consumes ~2400 kg/s of propellant. ~1800 kg/s of this propellant flows through the preburner of which ~33 kg/s is fuel (RP-1) and  ~1767 kg/s is oxidizer (O2).  The RP-1 is combusted in an excess of O2.
"If one assumes that roughly 1 lb of fuel is required to generate 1 lb of thrust"  that would be a terrible engine.  The RD-170 produces ~7900 kN vacuum thrust while consuming ~1729 kg/s of O2 and ~665 kg/s of RP-1.

The preburner fuel (RP-1) flow of ~33 kg/s is ~5% of the inlet fuel
(RP-1) flow.
The total preburner propellant flow of ~1800 kg/s is ~75% of the
total inlet propellant flow.

Source: Cycles for Earth-to-Orbit Propulsion by Manski and Levack


Why the trace of the Elliptic curve should be positive?

Question: In https://eprint.iacr.org/2014/130.pdf , has been suggested to select the positive trace. What is the reason for this? What happened if we select the negative trace? Is there any security problem for negative traces? How for Edward curves?
Answer: The cause I see in the paper is:

To ease implementation, we demand that r < p for all
curves, i.e. we choose the curve with positive trace

The prime $p$ is chosen as very close but below a power of 2 (e.g. $2^{384}$). Positive trace ensures that the number of points $r = p+1-t$ is less than $p$ and so does not overflow the chosen power of 2. This avoids e.g. arithmetic mod $2^{384}+\epsilon$ which would waste an extra 32-/64-bit word.
Comment: Thank you very much. This means that, the negative $t$ doesn't have security problem but implementation problem. Is it right?
Comment: Your answer is valid for weierstrass curves. It doesn't seem to be valid for Edward curves. Because in these curves, we work on subgroup $r$, not in $4r$ or $8r$. In this case, the bits of the scaler is always less than $p$'s bits.
Comment: In Sec. 4.3 of the paper you can note that they use an "updated" scalar of the shape $4(ar + k)$ for the purpose of having the same bitlength for all initial scalars $k$. So, while the cofactor is 4, it is not excluded in the computations but actually added explicitly. I guess to force the resulting point to be in the target subgroup.


Seeking advice regarding buying a telescope

Question: I'd like to buy a telescope with a focal length of 700mm and an aperture of 60mm.
Would I be able to use a telescope of this power to study the closer planets (for example Mars and Venus) and nebulae?
Comment: Mars, venus and stars in orion (perhaps you mean the orion nebula) can be seen with the unaided eye - no telescope is needed, so could you refine your question.
Comment: You also might want to include your location and estimate the light pollution where you're likely to be observing from (i.e. are you in a large built-up area with lots of street lighting nearby?)
Comment: @DrChuck That's a pretty literal-minded comment. Of course Mars is visible with the naked eye. OP is almost certainly interested in seeing more than the unaided eye can see.
Answer: All the magnifications listed above 84x will be useless on a 60mm telescope.
Still, such a telescope can be useful if it is well made (particularly a steady tripod/mount) and you have reasonable expectations.
It will show lots of detail on the moon.  You will be able to see the phases of Venus and Mercury (which is pretty much all anyone can see of those from Earth).  You will be able to see Mars as a disk and maybe glimpse an ice cap or a little surface detail under excellent seeing with a favorable apparition.  You will be able to see Saturn's rings and Jupiter's moons and maybe with good conditions a band or two on Jupiter.
It will only show a few of the very brightest nebulae, and only as a faint smudge.
Comment: Mars is going to be very tough in only 60mm of aperture. It's going to be very rare that any surface features will be visible, if ever. Jupiter's equatorial belts, however, will be much easier. I see them all the time in my 50mm finderscopes. I agree with everything else.
Comment: Mecan build my own telescope so what material i need
Answer: In my opinion, 75mm is the minimal requirement to say that device belongs to "telescope" class.
Magnification itself is useless. For every doubling of magnification you pay with dividing luminosity of your image by 4.
Also check out this black list of telescopes ref.2. All of these have defects which you, as beginner, will have real pain to cope with. As you can see, many of those telescopes are from serious firms. It means that even those are buying cheap parts and save their expenses when producing.
From lower end of telescopes (of refractors), which I consider less or equal of 90mm, I think that most beginners should choose between computerized versus non-computerized model. If you pay for computerized model, you will loose significantly in optical quality of your scope. Example of such choice: Meade Polaris 90 VERSUS Celestron NexStar 90 GT. The most "bang for the buck" choices, from trusted makers. (I do not advise in favor of any manufacturer! If you fall deeply into astronomy, build your own telescope!)
Don't fall for chineese ultra-low-end scopes. You cannot check their optics by web.
PS. If you are strongly on budget, I would even advise to NOT buy any telescope. Make your own. Buy 200mm mirror from trusted source (approx 100-200 bucks) and work your way to telescope by yourself and garage tools (such telescope costs over 500 bucks in stores). Check out ref.1.
PS2. For the planets, your choice of telescope falls more into category of large focal ratio. F/10 works good. Downside is that nebulae are large and could not fit into such narrow angles. Upside is that telescopes with F/10 are moderate at cost. Parabolic mirror could be swapped with spheric and so on. Another downside is bigger weight, because of longer tube (newtonian and galilelian telescopes). Modern schemes like Maksutov/Schmidt-Cassegrains are somewhat "more universal", combining good elimination of spheric aberration with wide angle. But weight is very large. Only buy with EQ5 and EQ6. Or with custom computerized mount.
At last. Best telescope is the one which is looked through everynight. Best telescope manufacturer is your own hands.
References.
[1] Number one site for ATM https://stellafane.org/tm/atm/
[2] Black list of telescopes http://www.star-hunter.ru/en/black-list/
Answer: Have you ever looked through a telescope of that size? Astronomy is a hobby enjoyed worldwide. There are astronomical clubs just about everywhere there are people. I would suggest joining a club nearby and getting familiar with the hobby before buying anything.
Electronics has found it's way into Astronomical viewing in recent years. What was no more than a faint smudge in an eyepiece is now clearly visible with modest equipment. Find out what others are doing before making any decisions.
As already said the best telescope is the one which is looked through every night. The only way to determine what is best for you is to look through a few telescopes first then think about what sort of equipment will make you want to use it whenever the skies are clear.


Bulb replacement in a car 12V 60mA vs 14V 65mA

Question: The climate control in my car needs to have some  backing lighting bulbs replaced. Can I use a 14V 65mA bulb instead of the 12V 60mA bulb that is suggested by other people who have replaced these bulbs? Not sure but I believe the orginal burnt out bulb is a 12V 70mA. Anyone forsee any problems using the 14V bulb.  Thanks!
Comment: tried applying ohms law to solve that question?
Comment: A neat solution would be to wire in some LEDs
Comment: Yes it should be fine. They will be a bit dimmer when the car is off, that's it.
Answer: There are three concerns when replacing components like bulbs

Exceeding the power rating (Watts = Volts*Amps, the voltage and current going through the bulb) which could be a thermal problem and heat things up to much. If you use a lower wattage bulb, you should be fine.
Exceeding current, The driving circuit in most cases should be fine, but its a good idea to stay below the current of the original part, you'll want to stay in the same range.
A bulb that is built for 14V says that because of the lifetime and/or brightness rating, that's what it was tested for. Since it draws about the same amount of current you should be fine. The bulb might be dimmer but it should be about the same or higher resistance.
Comment: For your item 1 it needs to be made clear that the (Volts*Amps) relates to the volts applied to the bulb and the actual amps that is drawn through the bulb. That will be the actual power (watts) consumed by the bulb. The ratings stamped on the bulb may not represent actual in usage wattage unless the applied voltage is the same as the voltage stamped on the bulb.
Answer: I don't see a problem in using that 14V bulb just so long as its current rating is about the same as the one to be replaced. It may not be quite so bright but I doubt if you will notice.
But consider this: an automotive bulb may be rated at 12V but it is designed to work across the range of voltages present on the car electrical system. With the engine running fast the alternator will output at least 14V. With the engine stopped the battery provides a voltage between 11V and 13V depending on its state of charge. Your 12V bulb is designed to work across this range of voltages. You could even call a 12V bulb "14V" because for most of the time it is working at 14V. An automotive grade bulb should also be sufficiently robust to withstand the shocks and vibration in a car. A 14V bulb probably isn't automotive grade and may not be quite so robust. Personally I do not see any advantage in using a 14V bulb. Get a good quality 12V bulb and as an instrumentation backlight it should last the life of the car.


Why did the Bell 103 modem use a data rate of 300 bps?

Question: Virtually every telephone modem in existence runs at a data rate that's a multiple of the Bell 103A's 300 bps.  Why was the base 300 bps chosen in the first place?
Comment: @user3169, in that case, could you add to whichever of [what constitutes "retro"](http://meta.retrocomputing.stackexchange.com/questions/2/what-constitutes-retro) or [what constitutes "computing"](http://meta.retrocomputing.stackexchange.com/questions/47/what-constitutes-computing) that you feel is appropriate?
Comment: I'm voting to close this question as off-topic because it is asking about technology history, and is not related to retro systems specifically, other than by age.
Answer: The signalling rate (baud) is constrained by a few things. Probably most important is the maximum signalling rate (roughly, how many changes a second) of the path the signal takes (i.e., POTS wires). How many bits can be represented by one signalling change gives us the bits per second.
I think the early Bell modems were 110 baud and used frequency-shift keying (FSK). This gives us one bit per signal change, or 110 bps. Similarly the Bell 103 had a signalling rate of 300 baud with FSK giving us 300 bps.
110 and 300 baud were chosen at the time primarily because both modems were intended to be used over copper wire and "unconditioned" telephone lines, with at least one part of the connection going through an acoustic coupler. The worst-case for acoustic couplers talking to carbon microphones is somewhere around 300 baud. Since this is a worst-case, this is what we get.
(I recall 110 baud was related to reliable half-duplex teletype comms, but I might be wrong about that. @jameslarge points out that 110 baud/bps was the fixed, unbuffered rate common teletype terminals supported. 110 was probably chosen for many of the same reasons discussed here. e.g., robustness and reliability on dodgy copper and carbon connections.)
This could theoretically be increased, but reliability suffers.
A natural improvement is to increase the number of bits that can be transferred for each signalling rate, which is what newer modulation techniques like PSK, Trellis, etc. gave us. The baud rate can stay the same so that it is within safe parameters for unconditioned lines, and the bit-rate can be increased.
As phone lines improved and lines could be counted on to be conditioned (and we knew there wouldn't be a carbon-microphone step in there somewhere) and advances in modulation error correction and error detection, baud rates increased. This led to increases in bit-rate.  I think the last telephone modems had a baud rate of 8000, and modulations that allowed for 56/46 kbs as a result.
Comment: Re, "110 baud was related to reliable half-duplex teletype comms".  Those old FSK modems didn't buffer the data.  The baud rate, which was the also the bit rate, was directly controlled by whatever device was attached to the modem.   A Model 33 Teletype (ubiquitous in those days) transmitted at a fixed 110 bits per second.
Comment: Making a teleprinter or tape punch that could output 30 characters per second rather than ten was difficult but not impractical, and would save 2/3 on transmission times vs 10.  Being able to send data faster over the wire is only helpful if the things on either end can keep up.
Comment: @supercat: I recall teletypes going out of use around 1974, while people were using phone modems with acoustic couplers ca. 1978.
Comment: @BenCrowell: I've used acoustic couplers s a few times, though I doubt it was before 1980.  My point was that improving the data rate from 10cps to 30cps was useful; going to 30cps to 300,000cps would have been, relatively speaking, far less useful.  I don't know how 30cps Decwriters were implemented internally, but I could imagine a practical way to implement the electronics even with just transistors and diodes (7400 logic would be helpful, of course).  Going beyond that would start requiring much fancier electronics.
Answer: 300 bits per second has the advantage that it is the lowest common multiple of both 50 and 60.  These made it easier to use the power line frequency (50 Hz in Europe, 60 Hz in USA) to synchronise the bit timing circuits.  This was long before Quartz locked circuits became cheap enough to include in teletype equipment.
Comment: Welcome to Retrocomputing Stack Exchange. This is a good first answer; thanks for sharing this information. You might be interested in [these related questions](https://retrocomputing.stackexchange.com/questions/tagged/hardware+or+hardware-testing+or+power+or+terminal).
Answer: 10 CPS/110 Baud was the maximum rate these signals could be sent with acceptable sidebands using an all-mechanical system. 300 was 3 times the teletype speed, and that limit is set by the 4 kHz maximum bandwidth of a phone line and the allowable harmonics.
300 baud is exactly 3 times 110 Baud, measured in characters.  The teletype standard was 110 bps with 1 start and 2 stop bits. That, plus 8 data bits (7 plus parity) equals 11 bits per character.   110/11 = 10 CPS.  300 Baud used 1 Start and 1 Stop, plus 8 data = 10 bits per character.    300/10 = 30, and 30 cps is 3 time 10 cps.
Mechanical teletypes such as the ASR33 sent 10 CPS.  They had a rotary wheel that spins when a key was pressed.  It had 11 contacts.  The first was wired to break the current flow in the communications wire. This was a current loop, sent over a phone line back to the Central office, powered by a 48V DC battery. The last one or two contacts were wired so that the current was always on.
The 2nd through the 8th contacts were wired to a 8 switches that were pushed by a matrix that encoded ASCII from the TTY key that was pressed.  Pressing a key released the motor clutch, the rotary contact wheel would revolve, and the make/break of the rotary switch would send the signal over miles of wire back to the central office at 110 Baud.  This yields exactly 10 CPS. This had a start bit, a stop bit, and either one or two extra stop bit(s), a spacer, to allow the system relay to re-energize when no more characters were being sent.
Later FSK systems could run at 300 Baud, and not being mechanical, had no need for the 11th bit (the second stop bit).
300 Baud systems were the first electronic systems, and could stop without an extra stop bit, which increased speed by nearly 10%.  The signals were modulated by FSK between two frequencies for transmit, and two for receive.  Switching signals between these frequencies generates harmonics, which have to be kept within the 4Khz bandwidth of the phone system to prevent crosstalk.
The odd 11-bit 100 baud standard versus all other bauds being multiples of 10, (300, 1200, 2400) are caused by the differences in mechanical and electronic FSK/PSK systems that evolved.
With PSK (Phase Shift Keying) the amplitude and phase were changed.  This fit within the same 4KHz signal bandwidth with the same sidebands.  Each additional amplitude or phase shift doubles the number of bits sent per Baud, thus we ended up with 300, 1200, 2400, 4800, 9600 and so on.
Comment: Is there any reason you know of *why* they picked "3 times the teletype speed" though?  If you could expand on that it would go a long way towards fully answering the original question.
Comment: @mnem: I don't know why a speed of 30 characters/second was chosen, but it was probably chosen as a tradeoff between speed, reliability, and the cost of building equipment to *do something useful* with data at the higher speed (e.g. punch it to tape).  Also, from what I've read, it's possible to use a "dumb" 300 baud modem at slightly over 400 baud, but reliability tends to go downhill at faster speeds.  A speed of 300 baud offers a fairly decent safety margin versus 400, and should thus offer reliable transmission.
Comment: They picked 3 times the speed as 3 X 110 = 3300, which  was the highest integer multiplier that is below 4,000, the bandwidth of the link.  .
Comment: It was usually possible for the comm program to choose how many (if any) start, stop, and parity bits to use, even at 300 baud.
Comment: "to prevent crosstalk": could you expand a bit on that? Didn't the phone system include a filter to exclude all signals above 3400 Hz?
Answer: A very good first answer however I would also like to note that any data rates above 300bps could not be acoustically coupled and were direct connect modems only.  And anything 33.6K and above basically demands at least one digital endpoint.  By that I mean that the modem access concentrator would connect to the Public Switched Telephone Network via data-grade T-1 or larger (see also AT&T T-Carrier) data trunks.  The DS-1 that rides the T-1 is channelized and the DS-0s are 64K clear channels and thus suitable for data rates up to 57.6K plus some protocol overhead and error correction.  The end user has significantly lower upload speeds because they're using analog (voice) lines.  This is also the genesis of today's asymmetric residential data model.
But it all comes back to baud rate.  Bit rate is a measure of the number of data bits transmitted in one second.  Baud rate is the number of times a signal in a communications channel can change state in one second.  Regardless of the techniques used to encode bits in a carrier, the baud rate was always a limiting factor and was determined by the dynamic range of the signal processors available in the PSTN at the time.  110 Baud was safe.  300 Baud was pushing the limits of signal processing available in the 60s and 70s.  And from there we were able to stack new methods of line coding and framing on top of that 300 Baud to make it almost up to 64Kbps.  Amazing, huh?
Comment: Are you sure acoustic couplers were limited to 300bps and not 300 baud?  I'm 99% certain later encoding schemes allowed for a 9600bps max rate through a coupler.
Comment: Also note that there were asymmetric rates as well; 1200/75 was common on viewtext systems
Comment: I see no basic technical reason why acoustic couplers couldn't, in theory, be used at any speed as the signals are encoded as sounds in the audible range. There is a definite risk of more errors creeping in with the extra equipment involved and the air gap, but no extra A/D conversions involved. **However**, the Hayes Smartmodem and successors allowed for auto-dial and other features that required a hardwired connection. Hardwired connections in general were enabled by the Carterfone ruling in 1968 - combined with progression of microelectronics *and* higher speeds, hardwired took over.
Answer: As stated above, 110 bps/baud was necessary for a 10 cps MECHANICAL device.  The two stop bits were needed to allow for the proper printing of the character.  The original 101 modem used a 200 Hz shift (1070/1270 Hz for one band, 2025/2225 for the other band).  Given the 200 Hz shift and the nature of the serial data, 300 bps would yield a max frequency of 150 Hz (a pattern like *U in ascii) with alternating bits.  This with the max shift made for a good error margin for the speed given.  If you were lucky (which was rare), you might be able to push a 103 modem (a later incarnation of the 101 modem which had better filters and the like) to go 450 bps but that was about it.  Most people used 300 bps as the speed of choice as it worked out OK.  Also a 30 cps mechanical printing terminal (there were a few) was about as fast as mechanics would let you go.  Much more and things would fall apart, or the time necessary for the physical carriage (printwheel, etc.) to 'return' to the left margin would be to excessive.
With higher speeds you needed to go to asymmetrical speeds like 1200/75 to fit the asynchronous tones in the telephone baseband (bell 202 modem tones, still used today for caller ID data).  Later (in the mid 70's) ICs and such allowed for more complex modems, and synchronous data transmission, even if converted back to asynchronous start-stop communications (Bell 212 modems).  This started the upward trend to faster modems using all sorts of techniques (fancy modulation) to get the speed up.  The limit of a phone line (a DS-0 signal, 8k samples at 8 bits) was reached with the 56k modems (in the US, one of the bits is taken out periodically for signalling and couldn't be used).
Now?  We all use DSL or cable modems which don't have limitations like these.
Answer: A slight tangent but my first computer, a clone of the Ohio Superboard II called the UK101, had a cassette interface which was 300b/s using the "Kansas City" method of FSK. The computer had a simple UART whose TX connected to the frequency control of a simple modulator, and RX connected to a crude frequency detector and thus derived the binary stream from the "warble" of the FSK.
With a higher quality cassette recorder it was possible to run the tape interface at 600 baud (I can use baud and bps interchangeably in this context) or even 1200, but the latter was very supsceptible to the slightest tape glitch.
Or, you could build an RS232 level converter and connect the UART to a 300 baud modem.


Magento 2.2.1 "Sorry, but something went wrong. Please contact the seller." Checkout using Authorized.net

Question: Magento 2.2.1 : I have confirmed the transaction URLs, keys, and MD5 with Authorize.net. Transaction is processed and deducted from account.  Order is created within Magento, and emails are sent. However, the error message tells the customer at the time of the transaction that it has failed. When they attempt it again, it double charges them.
I have reviewed all logs and there is absolutely nothing being logged in system.log, error.log, debug.log with respect to the transaction.
Are there any other logs to review?
How can I properly inspect the browser session for response messages?
I have seen a similar issue in the past on a different website using 2.1 and the issue was with the transaction url. I corrected it to api2 and all worked well.
UPDATE:
I have switched to the Magento Blank theme and the issue still exists.
While viewing the console under the browser inspect, I see the following:
Refused to display 'https://www.<mydomain>.com/authorizenet/directpost_payment/redirect/x_invoice_num/000075321/success/1/controller_action_name/directpost_payment/is_secure/1/' in a frame because it set 'X-Frame-Options' to 'deny'.

Is this an issue with respect to what I am experiencing?
Answer: Check the value of frame options in:
app/etc/env.php

I resolved it by setting it to 'SAMEORIGIN':
'x-frame-options' => 'SAMEORIGIN'

I experineced the issue when set to 'DENY'.
Comment: Congrats! Please also consider to mark your answer as accepted if you believe it resolve your problem :)


Use of Encrypted Fields in List views and Reports

Question: Am I able to use Encrypted Fields in filter criteria in list views, reports and communities? Is there documentation anywhere I can find? I want to verify before rolling out encryption?
Answer: There are various limits on listview / reports when using deterministic encryption
In particular, you can not do:

Filter on Contains or Starts With or any relative operator (>, < >=, <=)
Use the column sort on any encrypted field in a listview (as Order BY is not supported). This does not affect reports, only ListViews

I strongly suggest doing this in a sandbox and testing first.
Answer: Yes, if you encrypt a field with deterministic encryption you can filter on that field in list views and reports (and even SOQL if you need).
The documentation for deterministic encryption is here.


Is there a way to freeze/cache nodes so that it doesn't have to reprocess everything?

Question: I'm working on a geometry nodes setup, there is one node which input doesn't change, but this node takes a long time to calculate, and I'm constantly changing things that aren't affecting this node, is there a way I can skip its calculations? Kinda like the freeze icon in Houdini. I guess the answer is no, since I couldn't find anything, but maybe someone knows something cool.
Answer:
This answer is for Blender versions lower than 3.6, if you are using 3.6+ you can find the solution in the other answer.

No, unfortunately this is definitely not possible in Blender with Geometry Nodes.
...even if I would like to have exactly this possibility as much as you!
Either the nodes are active and create a geometry, or they are not.
A temporary caching of a certain part of a node tree, as it is possible for example in Houdini, is unfortunately not achievable in Blender.
The only alternative you would have would be:
Create the computationally expensive part as a separate node tree, and create a permanent geometry from it each time by applying the modifier. However, this process would then have to be performed again after each modification.
Answer: It is no longer true that Blender cannot cache the result of a node in Geometry Nodes.
From Blender 3.6 and onwards, Blender Foundation have added the Simulation Zone nodes to Blender, which can encapsulate a portion of your nodes.
Once you have successfully encapsulated the nodes you wish to cache, move over to the Physics tab within the Properties editor and find the Simulation Nodes section. Note that while this was placed in the physics section, it will cache anything that comes out of the zone, not just physics.
If it is not expanded, expand it. Now you can select the Cache checkbox, and then choose either the Calculate to frame or Bake options to cache the data which you need.
Once this is enabled, you need to delete the data with the little trash can button next to bake to remove the data or click bake again (or both) when you do something that might update the results of the nodes within the simulation zone.
Also note that for versions 4.0+ Blender has another zone type called Repeat Zone, which is distinct, and at the time of writing this does not allow caching for that zone type (unless perhaps if encapsulated in a simulation zone, but I have not tested this to see if it works).
I am hopeful that they will add some smarter built-in caching and detection of which changes in data flow would require updating of caches automatically, but Simulation Zones are what we have for now.
Comment: Sadly, at its current state it's a little bit of a *"out of a frying pan, into the fire"* situation - sure, sometimes you have a complex process generating a light geometry, but if your geometry is complex (basically a lot of vertices), a simulation zone will quickly flood the cache.
Comment: For something complex, what I did was limit the number of frames in the timeline editor. That way, you can see the results without the complexity getting out of hand as the frame number increases, since it will start over after just a few frames. It's a workaround. It still isn't ideal, since it would be better to be able to cache the results of Repeat Zones in Blender 4.0+. Repeat Zones let you determine the number of iterations to perform all at once. You could store the results for each iteration by having a separate output for each iteration increment, but that kind-of battles the purpose.


how can i install ubuntu 14.4 LTS from windows 7 using windows installer?

Question: when i tried to install ubuntu from bootable USB it couldn't recognize my installed windows 7 so it showed me like i have to erase my whole drive and then ubuntu can be installed. please help me with this ASAP.
Comment: Check [this answer](http://askubuntu.com/questions/319792/ubuntu-does-not-recognize-existing-windows-partitions-in-a-gpt-disk#319856)
Comment: There are many threads about this issue. Did you put any effort in looking for existing answers?
Answer: Ok, This should not be a problem.
First try with wubi which comes with Ubuntu 1404 LTS CD. Inside there wubi icon can be found. Once you double click it, it will starts the installation as a normal windows program. But what this does is that it installs the Ubuntu on the system as a dual boot  instead as a program inside the windows. Thats all..
When system rebooting it will give you list of OS to select.
Answer: In the Ubuntu terminal, execute the command line below:
sudo update-grub

Then reboot the system, then you could see the boot menu options including both windows7 and ubuntu.
Please refer to:
Problems installing and dual booting Ubuntu 12.4, 13.10, and 14.4.1 via pendrivelinux?