Aurora Effect from Galactic Wind?

Question: The Solar Wind creates auroras due to interactions with Earth's Magnetic Field.  Do we witness any similar effects from the Galactic Wind interaction with the Sun's Magnetic Field?
Answer: The auroras are not interaction of the solar wind and the Earth's magnetic field. The light is produced, because the high energy particles from the sun excite atoms in the earth's atmosphere. The earth's magnetic field "guides" the particles towards the magnetic poles of the earth, that's why you don't see the aurora often anywhere else.
Similarly high energy particles from the galactic wind could excite atom's near the magnetic poles of the sun. But I don't know if the effect is observed.
Answer: We have observed aurora-like emissions on Jupiter, Saturn, Uranus, and Neptune.  The emissions on these larger gas giants (well, ice giants really) are often in the UV wavelength range, so special telescopes are needed to see them.  You should note that the emissions are incredibly weak.  So to see anything near the sun is probably a hopeless endeavor since it is the "loudest" radio, microwave, visible light, UV-light, X-ray, and $\gamma$-ray (well, I am not so sure about $\gamma$-rays) source in the sky.
The aurora are actually created through an interaction between the solar wind (its dynamic pressure and magnetic fields) and the Earth's magnetic field.  The particles that ultimately lead to the emission are high energy particles (10's of keV electrons) hitting the atmosphere and exciting nitrogen (green light) and oxygen (red and green light).  These particles come from the Earth's geomagnetic tail (i.e., the region opposite the sunward direction), not the solar wind directly.  They are accelerated during their journey from the tail to the auroral regions (i.e., magnetic poles) through multiple processes.  Some even have enough energy to produce UV and X-ray emissions, though these are not the dominant emissions on Earth.

Aurora Effect from Galactic Wind?


Side effects of wire mesh inside vent covers

Question: I am considering tacking wire mesh (such as from a window screen) onto the inside of my indoor furnace/AC duct vents as well as the outdoor intake vents, for pest control. I know doing it inside the house might be a little overkill, but I'm wondering if there would be any side effects on furnace/AC performance due to the fans having to work harder to force the air through.
Comment: Identifying what kind of pest problem you're having may get you better solutions to the actual problem instead of suggestions that your band-aid solution isn't a good idea.
Comment: what is an outdoor intake vent? - is that a real thing on houses?
Comment: @dandavis good question. I guess technically they are not outdoor but in a loosely sealed three-season room where bugs seem to get in to.
Answer: Typical screening can reduce airflow about 50 to 70%. This could destroy the efficiency of your AC and heating units and possibly burn out the fan. Placing any type of screen on intake or exhaust of your furnace could cause it to shut down as it thinks there is a blockage in the venting. Your furnace /AC unit already has a filter on the intake side of the fan so you wouldn't need screening on the individual vents in the rooms.
Answer: By "pest control" do you mean insects or rodents? Larger mesh, also called "hardware cloth" would not significantly impede airflow and will stop rodents. Window screening will clog with dust and cause you nothing but problems. If you were thinking window screen to prevent insects, you need no worry about them entering from the outside that way. To get through the ducts and into your house, they would ahve to get through your air filter.
Comment: Insects. And thanks, I appreciate the answer.


Orange light that rises quickly and moves of to the righ

Question: I have recently noticed an orange "star" (or what I presume to be a star), rise above the hill line behind my home. It rises later than every other star and rises within a few hours while the other stars are stationary! It moves off to the right when half way in the night sky this happens every night when clear for the past few months. I also believe I'm looking south. It's really bugging me. Could anyone identify this object from my description?
Answer: The object is (most likely) Mars! It's been rising in the south as of late. When it will rise of course depends on your location...for me it rises pretty close to sunset. Planets appear in an essentially constant position relative to the background stars over the course of the night, and as with the stars, the movement you see is due to the rotation of the Earth. Over the course of weeks, however, you can see the planets change position relative to the stars due to their motion in their orbit around the Sun. We don't see this wandering of position with stars - at least, not in an amount or on a timescale we can appreciate - because they're so far away.
Keep an eye out for other bright objects in the sky that appear to move faster and (unless conditions are poor) don't really twinkle, especially near sunset before the stars properly come out - Mars probably isn't the only planet you can see! Jupiter, Saturn and Venus are often visible as well.
Check out this site if you want to see what planets are visible from your location and when.
https://www.timeanddate.com/astronomy/night/
ETA: Corrected explanation of planetary motion vs. motion of stars based on James' comment.
Comment: I agree that it is likely Mars.  But you are wrong to suggest that it's proper motion causes it to move across the sky. The motion of the planets relative to the stars is too slow to notice, unless you observe them over several weeks.  Planets do not appear to move faster than stars.
Comment: Ayaah, you're right, I read a few more things I and I definitely misused the concept of proper motion. I meant its motion in its orbit in the Solar System.


Can't delete messed up user profile as admin on a new computer with windows 8.1

Question: This is probably (hopefully) super basic for you guys, but I'm new to Windows 8.  Just got a brand new computer to upgrade from our ancient Vista machine.  I think I know just enough to be dangerous.  My son helped me get started by creating my account first as admin.  I copied all of my user data over from my old PC and put it in appropriate places.  Then I created my husband's account, also as admin, and started to copy his user data over.  When I finished, things didn't look right.  Somehow the account had reverted to a regular user account and it wouldn't let me change it back to admin.  So I deleted the account and created a new one.  Then I discovered that deleting the account didn't really delete the account and when I created the new one with the same name things got even more confused.  So now I have 2 funky accounts hanging out there and I'd really like to get rid of all the related files and start from scratch but even with admin permissions it won't let me delete some things.  How do I get rid of those bad account remnants?  Worst-case scenario is there a way to revert to the beginning and start all over?
Comment: Did you create local accounts or Microsoft accounts? If you can log in using an administrator account (a working one) go to `c:\users\` can you get into the folders and see files?
Answer: Well apparently all that was required was a reboot because this morning I am able to delete everything that I couldn't yesterday.  I'm relieved but not digging Windows 8 so far.  Thx


Travelling to the US with prescription medication Sertraline

Question: I will soon be traveling to the US (New York) from the UK for a two week trip. I have a prescription for Sertraline (Zoloft) that I will need to take with me. I have the original prescription documents and packaging. Should I expect any delays or issues at customs and what's the best practice to avoid this?
Comment: @Milla Customs is not going to enforce something like that for medication bought in by a bona fide traveler for personal use.
Comment: Astonishingly we don't seem to have a duplicate of this.
Comment: @DJClayworth I thought  https://travel.stackexchange.com/questions/31372/flying-to-the-us-with-prescription-antibiotics?noredirect=1&lq=1 covered the subject, although it was a different drug (still not a controlled substance) and had no response to the OP's query about experience.
Comment: Suicide & antidepressants The FDA requires all antidepressants, including sertraline, to carry a boxed warning stating that antidepressants increase the risk of suicide in persons younger than 25 years. https://en.wikipedia.org/wiki/Sertraline#Suicide
Answer: US immigration/customs does not routinely ask about what medication you may be travelling with, nor do the routinely search bags on arrival.
Thus it is most likely carrying this medication will have zero impact on your entry to the US, and will not cause any delays in any form.
In the unlikely event you are asked, then you should answer honestly. Zoloft is a common medication in the US, and whilst it is a prescription medication it is NOT listed under the Controlled Substances Act (which generally contains drugs which are deemed to have the potential for abuse) and thus it's unlikely that customs is going to be at all interested in it.
The US Customs and Border Protection websites has details on what is required when travelling with prescription medications, but they are things that you have already stated you planning to do, along with the recommendation not to bring more than a 90 days supply (although this can depend on the length of your planned stay in the US).
Answer: Here is an article from the US Customs and Border patrol giving the basic facts about bringing prescription drugs.
The main points are:

Prescription medications should be in their original containers with the doctor's prescription printed on the container.
Bring only enough for personal use - a maximum of 90 days supply is recommended.
If your medications or devices are not in their original containers, you must have a copy of your prescription with you or a letter from your doctor.
A valid prescription or doctor's note is required on all medication entering the United States.

The page contains links to further information.
In general having prescription medicines will not cause any issues, as long as the guidelines are followed.
Comment: My prescription comes in a small plastic jar with a childproof lid and a sticker on it. The sticker has my name, the name and address of the pharmacy, medicine name, dosage and instructions, and a reference number.
Comment: @WoJ stock photo example: https://media.istockphoto.com/photos/perscription-drugs-picture-id510723503
Comment: *Prescription medications should be in their original containers with the doctor's prescription printed on the container* Out of curiosity, what does this look like? In Europe, we have paper boxes in which there is either a bottle or a sheet of sealed single capsules. The prescriptions are always separate. I saw that in the US you get refills (which is great because people do not get more medicine than they need, no waste) but how is there space for something from the MD, and how does it get there?
Comment: Ah, I get it now - when it says *with the doctor's prescription printed on the container* it means that what the doctor wrote in his prescription is written as part of th label. I was trying to imagine the *original* prescription being on the label :)
Comment: note how this US style label also contains your name as the authorized recipient, in addition to the drug information -- all this should match up with reality


Dark matter pressure

Question: Dark matter is suppose to form large halos of unknown yet type of particle with a specific density density profile. Does the dark matter halo can be viewed as a fluid of particles with density and non-zero pressure? Which kind of equation of state one could expect for the dark matter fluid?
Answer: The answer to your first question, about considering dark matter as a fluid, is that when you are modelling the different components of the universe ('common' matter and dark matter, radiation and dark energy) you work with them as they were perfect fluids, that means no viscosity nor heat conduction.
About the equation of state and the pressure related with this component of the universe I have to say that all these components are studied with barotropic equations of state (the pressure of the fluid only depends on its density):
$$ p=\omega \rho $$
with $\omega$ a constant that depends on the component. The pressure associated to the dark matter is non-zero but it's so small that is possible to consider it as zero.
Comment: One property that is associated with dark matter is that it has to be cold (CDM), that means that most probably is formed by non relativistic particles. So when people model these different components of the universe as barotropic fluids the distinguish relativistic and non relativistics components with different values of the constant $\omega$ ( $\omega = 1\3$ for ultrarrelativistic components and $\omega = 0$ for non relativistic ). These values are the limit situations, you can find possibilities in betwn $0<=\omega <= 1/3$. Smthng funny is that to describe dark energy you need $/omega=-1$.
Comment: I was reading other questions and since the dark matter is collisionless, then one should expect $P=0$, however, in Nature anything is perfectly 0, so, are there limits for $P?$ who has measured that?

Dark matter pressure


ASP.Net Page abstraction

Question: We have a win application that shows a web form in a web browser.
In order to get data from this web form we are using a hidden text box and get its text using HtmlDocument object of web browser control.
I want to make an abstraction of this web form that has this text box element so that other forms can use this abstraction.
I made a web control and put the text box on it.I thought that if I put this control on my page it would have the text box.When i ran my application I noticed that the text box had been rendered but had its control name in its name (WebControl$TextBoxName) and its id(WebControl_TextBoxName) and the win app throw an exception since it couldn't find the element by its id(TextBoxName).
So here's my question:
How can I make an abstract web form/web control that has some elements on it and I can use it to make my final forms have these elements on them? (their names and ids should not be changed)
Thank you for your help
Answer: Though I've never used the browser control in WinForms, I think what you want to use is a Master Page.  Assuming what you're rendering in the browser control is an ASPX page, create a Master Page with the hidden text box that you want to grab your data from, and tell all of the pages you want to have that common control on to use your Master Page.  When the page renders, the control id will then be "ctl00_TextBoxName".  There is no way of getting around the ID concatenation, since unique IDs are needed and that's the only way to guarantee uniqueness with all the nested control abilities of ASP.NET.  However, doing this will guarantee you always have that control named the same on every new form you create that inherits the Master Page.  Hope that helps!
In summary (because who reads paragraphs?):

Create Master Page
Place your common control in the Master Page
Have your Form inherit the Master Page

You can read up on how Master Pages work in MSDN's Documentation.
Answer: dotNet 4.0 supports static id's so they don't get mangled, read up on Client Id Mode
Alternatively, you could override the render of your control to output a standard html hidden form field with whatever ID you want, and then also add a custom property that will return the textbox that will hide the fact that it isn't an asp.net server control.

ASP.Net Page abstraction


Finding CML files for small molecules

Question: I'm trying to generate a figure for a physics textbook to show examples of the vector addition of dipole moments in small molecules. For this purpose, I would like to render pictures of a bunch of small molecules, such as CS2, formaldehyde, benzene, SF6, and chloroform. I've got avogadro running on my linux box, but I'm finding it very time-consuming and confusing to construct the molecules using the GUI. Is there anywhere that I could find pre-made CML files for small molecules like these?
Comment: Do you have access to chemoffice? Chem3D can produce 3D structures from formulas and if you run the optimization in there it should be good enough for this application. Other than that: how many molecules are we speaking about? With the right software making each of those takes less than a minute each including low level geometry optimization. If it's not too many I'm happy to help, we can speak in chat.

Another option: you can open the 3D model in jmol from their wikipedia page and extract the *.mol file which to my knowledge can be opened by Avogadro.
Comment: @DSVA: Thanks for the ideas, and for the offer of help. This pointed me to the info that I'll give in an answer to my own question.
Answer: DSVA's comment pointed me to a database that contains the information I need. The wikipedia articles contain links to an app called jsmol, but that app appears to be getting its data from a database called ChEBI. You can search the database using search terms such as "formaldehyde" or "sf6." The entry for each molecule contains a link to a .mol file, which avogadro can read.
Answer: Another location, if you're ok with the mol2 format (which Avogadro can open), PQR has links to download structures on every page. For example, on the cadaverine page:

This will trigger a browser download dialog box for a mol2 file.
Answer: Consider a blend of Wikimedia Chemical Structure Explorer and OpenBabel.

Wikipedia includes many entries about chemicals, and often, the property box right on top of the page (left, or right, depends on your script) include the condensed structure representation as a SMILES string:

(credit, the Arabic entry about toluene)
With above mentioned freely available, open source structure explorer which you may run without installation from a web browser (further description, e.g., in J Cheminform 7, 10 (2015)) you may query all of these entries by a (sub)structure search, a keyword, or a combination of both to access the English article and find the Wikipedia page on the right hand pane:

(screen photo of the explorer)
As by today, the public index contains 18484 entries.

With the help of OpenBabel, you may convert the SMILES string into the CML format (the the documentation presents many additional input/output formats, too).   After installation of OpenBabel, the program may used from the CLI / cmd.exe, or from a GUI.  Then, you have at least two options:
a) You save the SMILES string from wikipedia in as file, for example toluene.smi.  If you opt for a conversion from the CLI, the command
obabel -ismi toluene.smi -ocml -O toluene.cml
writes the new file toluene.cml.
b) You paste the SMILES string into the command on the CLI when writing
obabel -:CC1=CC=CC=C1 -ocml -O toluene.cml
to generate the .cml file right in the current working directory. (No, do not set a space between the colon and the SMILES string.)
The documentation lists many more examples and showcases the use of the GUI.  OpenBabel may work on multiple input files at once (e.g., obabel *.xyz -opdb -m to convert all .xyz of a folder into .pdb) and interacts well with other programming languages, too (introduction).
Answer: If you have Microsoft Word installed on a Windows machine you can use our open source Add In called Chem4Word to search the ChEBI database and import structures.
Once imported they can be optionally edited, then exported as CML.
You can find Chem4Word here https://www.chem4word.co.uk/download

Finding CML files for small molecules


Collusion in real life poker games

Question: How can casinos/players curb/spot collusion between a group of player (i.e. playing as a team in the same table)?
Comment: Consider accepting an answer to the prior related question.  At this point you have not even accepted that collusion is an advantage.
Comment: @Paparazzi Which prior related questions? Other than http://poker.stackexchange.com/questions/5833/are-online-poker-sites-rigged?
Comment: @TobyBooth OP can only accept an answer to his own question and OP only has one other question.  In that OP questioned if collusion is even an advantage.  No accepted answer and no comments.
Answer: Firstly, just don't. People tend not to take too kindly to cheaters, and even more so when the cheaters are taking their personal cash. If and when you'll eventually be caught you'll likely end up in some trouble. Not to mention it's considered stealing and you can get in legal trouble.
It depends on many things really, such as:

How good you guys are at it
The type of players your playing against
Casino staff experience
Type of casino

For how good you guys at I mean your system of collusion, giving each other a wink when you have the nuts seems like it'd be pretty easy to spot by anyone paying attention. Whereas say doing a specific chip trick when you have the nuts might be harder to spot. It will eventually be spotted I guarantee you of that.
For types of players, if you're playing at a local bar, small card room or a private game with recreational players they'll probably never notice. If you're playing at a big casino with grinders and experienced players they'll 100% notice it eventually. It's a pretty important aspect of poker to be able to pick up patterns of players and break down their meanings. Good players will pick up on it very quick.
Casino staff experience is a big one. I'm not just talking about the dealer, but floor staff too. This links into the type of casino too. If you're talking about a Vegas strip casino or a big one like that they are trained and have systems in place to pick up on cheating. Trust me, I've worked in the industry for several years, they're damn good at what they do. There is a reason you don't hear about the likes of the MIT Blackjack Team or Gonzalo Garcia-Pelayo, etc happening anymore. While a lot of these guys didn't get into legal trouble and many made a killing their methods were discovered, countered and ultimately most of these people aren't allowed into any casinos were you could make some decent money in. There is a Black Book in the gaming industry, you get into that good luck getting near any big gaming floor.
Smaller local casinos or cardrooms, yeah ok they won't have the experience nor the security systems in place, but they also don't have the amount of money that is worthwhile cheating for.
I really wouldn't recommend it because the type of casinos or cardrooms you could get away with it aren't worth the effort of developing a system. If you're caught too there can be serious repercussions.
Comment: @TobyBooth: indeed. I also got the impression Grinch91 thought I was asking how not to be discovered. But it was more about not to get scammed. It is pretty frustrating to play a rigged game.
Comment: I get the impression you think OP is going to attempt colluding/cheating at a poker game. Is this correct?
Comment: Not necessarily but sure the thought did enter my mind and the points can still be applied if not directed at you. Glad to hear you're not. The points can be applied as a general rule, if peoples seem to be communicating somehow, as in player a does x and player b does y 100% of the time after x...After awhile it becomes a bit more than a coincidence. Points about casinos, bigger ones anyway,show that they're are systems in place and staff are trained. I wouldn't really worry about it, if you don't trust the game don't play. I apologise if you took offense,like I was blaming you.
Answer: B&M Casino's really do not protect you from collusion. I have played and worked in many poker rooms and the simple fact of the matter is that they do not bust people for collusion.
People are not busted for collusion because it is simply so difficult to prove, and casinos do not have a vested interest in the game. When they 86 players they 86 paying customers.
Low to high levels of collusion is present in every poker game. When a couple of friends chop blind or do not play against each other that is a mild form of collusion. If you watch the Atlantic City scene in "Rounders" Matt Damion describes a basic mild version of collusion. There is more series collusion going on, flashing cards, acting out of turn. Some of it is just rude by a rude player, but a lot of it is part of team play. And yes strong collusion, where signals are going on and your being cut up by pros is not uncommon.
The casino cannot help, they do not have the means prove collusion. Only you can protect yourself by getting out of the game.
Online one might argue has better ways to spot collusion. However they are not going to bust a determined team, and if they do, they really cannot do much accept close accounts and perhaps seize won money. But that is not a big deal to a determined cheater, new accounts are opened, other sites are hit and it just goes on.
The bottom line is that you need to be able to defend yourself by getting out of the game, or make some new friends. Online or live, your ass is in the wind and you need to be a little paranoid and move on once in awhile.

Collusion in real life poker games


How do I disable the "can not set attribute" dialogue in Double Commander 0.7.4?

Question: Every time I copy files from my home (ext4) partition to a Windows (ntfs) partition in Double Commander a dialogue pops up saying "can not set attributes for... can not set date/time for..." and asking to choose between Skip, Skip All, Ignore All and Abort. I am to press "Ignore All" manually all the time. Can I just configure it to ignore this problem automatically?
Answer: Yes, you can configure to ignore this automatically.
Copy a file with F5 key or "Copy F5" at the bottom of Double Commander. A dialogue will come up, choose "Options". At "When cannot set property" drop down list select "Ignore errors". Then click "Save these options as default".


Gnome-keyring iteration count location

Question: I know that Gnome-keyring hashes the master password between 1000 and 2000 times. It picks a random number. I would like to ask where it saves this number, what is the location of that file? As far as I know it needs this count number when decrypting the files with saved passwords.
Answer: According to my reading of the source code (docs/file-format.txt), the iteration count is stored in the keyring file, specifically in the 25th through 28th bytes after the end of the keyring name.

Gnome-keyring iteration count location


How can I remotely trip a RCCB?

Question: Is there a facility to remotely trip a RCCB/RCD?  I'd like to put an emergency power off button on my server room and am wondering if I really need an RCCB/RCD /and/ a contactor?
Comment: RCCBs are not extremely reliable - certainly less so than a normal breaker. What happens when the emergency cutoff doesn't work?
Comment: I take it you do *not* want the ability to turn the room back on again? Also, I take it your EPO button is a Normally Open type?
Comment: 1. No, its in case of fire, for example. 2. That I'd have to check, should I be able to find such an RCCB
Comment: That comment is working on the assumption that you want to trip it directly, i.e. with earth leakage. Other ways are probably fine.
Comment: @SomeoneSomewhere  I'd be worried if a safety solution was not reliable, but your point is taken.
Comment: @Ian RCDs are generally considered supplementary protection, and are typically full of electronics. Sometimes stuff goes wrong.
Answer: You could use a RCD tester.   This is a device which places a sensibly sized load between hot and ground, aiming to induce more fault current than the RCD's trip threshold, proving the RCD works.
You could make one yourself out of a big red pushbutton switch and a right sized resistor.  Take the RCD's current rating (e.g. 30ma), multiply by 5 to get a nice sure trip, that is I (current).   You know your mains voltage, that is E (voltage). Apply Ohm's Law E=IR, solve for R and your resistor value pops out.  Size (wattage) of resistor: apply Watt's Law EI=W.
Answer: You need an extra option for this
Assuming your EPO switch is a normally open type, the typical way to do this at the panel uses a breaker with a shunt trip or shunt release option fitted, which will trip the breaker when power is applied to the shunt trip's terminals.  Most North American panelboard-type MCBs can be ordered with a shunt trip as a factory option -- however, it's limited in nature, and often cannot be applied to specialty breakers such as GFCIs/AFCIs.
However, what you can do is provide GFCI, GFPE, or AFCI protection for the branch circuits, and put the shunt trip on the main or feeder shutoff breaker.  That way, you only need one custom-ordered breaker instead of several, and also circumvent the incompatibility between specialty breakers and shunt trip accessories.
If you were back home...
If you were on the European system, however, DIN rail breakers are rather modular (compared to North American loadcenter/panelboard-type MCBs), so shunt trips for RCCBs are available as a general rule.  Most can be either factory or field fitted depending on the situation and breaker make/model.
(If you had a normally closed EPO, you'd need an undervoltage release option instead -- it's the inverse function of a shunt trip.  These are not as common as shunt trips, especially in North America although some European breaker lines have restrictions on the employment of their undervoltage release options that aren't present on their shunt trips.)
Comment: Thanks for this, this sounds like the best option.  I'm actually doing this in Colombia, which broadly uses the US system but without, as far as one can tell, any regulations (or at least their enforcement).

So a DIN module solution will probably be impossible to find, or at least expensive.  I'll see if I can find something I can install in the loadcenter.
Comment: @Ian -- what make/model is the loadcenter?  Also, *why* are you calling it a RCCB? Are we talking about a GFCI or GFPE breaker, or are you simply calling it a RCCB because you don't know what to call it?
Comment: I'm British.  I think we call them RCCBs or RCDs there, whereas Americans call them GFCIs.  Same thing, I think?

Under construction. I'm running totally new cabling back to the meter so I can put in anything I want, or at least anything I can find.  Typical options seems to be:

http://www.homecenter.com.co/homecenter-co/search/N-1yva90n?Nrpp=40&Ntt=Cajas+Tacos&sScenario=Cajas+Tacos&sTerm=caja+de+tacos&sType=keyword

I'd love to go DIN but it would make maintenance a bitch...
Comment: @Ian -- is there a reason you're putting a GFCI or GFPE device on a server room branch circuit? It seems like a *strange* application...although yes, a UK RCCB (RCBO) is basically equivalent to a North American GFPE *breaker*.  (The North American GFCI is available both in breaker and yoked form factors, and is basically the most sensitive GF device you'll run into, several times more sensitive than a GFPE or RCBO/RCD.)
Comment: In Britain it's usual to put an RCCB on pretty much everything.  Best practice, iiuc, is an RCBO per circuit, but usual practice is an RCCB on a group of a few breakers.  As some of the equipment in this room will be 1400W and needs to run continuously, I want to put an RCCB on each of those devices so if one fails it won't (or at least might not) affect the others.
I'll check out the difference between GFCIs and GFPEs, thanks.
Comment: Just had sticker shock at the the prices of GFEPs in the US. HMOG.  They're like an order of magnitude more expensive than a UK RCBO.  Now I understand why you were thinking it was strange.
Comment: @Ian -- how many branch circuits are involved here, btw, and are you planning on using a dedicated subpanel for the server room?
Comment: There's actually an unused but connected 60A meter, so I was doing to wire back into that with its own dedicated panel. They'll be 5 x 15A circuits, each pulling about 12A, off that fused at 60A overall.
Comment: Reading about shunt trip breakers, it would appear that there's a safety issue wrt providing reliable voltage source to the EPO/trip circuitry, and some people at least feel a contactor is the better way to go.  Any thoughts on that?
Comment: @Ian -- that's an issue of NO vs NC (shunt trip vs. undervoltage release, basically).
Answer: For the original poster and subsequent readers, I want to first clarify the terms used and summarise the purpose of each item, which should then help answer the question.

RCD = Residual Current Device
RCCB = Residual Current Circuit Breaker
RCBO = Residual Current Circuit Breaker with Overcurrent/Overload Protection

RCD and RCCB are two names for the same item. These terms are typically used in the UK to refer to a current-operated fault detector. If Line/Phase voltage does not equal Neutral voltage under load, current is leaking to earth/ground, possibly through someone's body. By breaking the circuit within defined tolerances of current and time, potential electric shock is avoided. An RCBO combines the function of an overcurrent device like a thermo-magnetic miniature circuit breaker or a fuse, with that of an RCD.
In North American terminology, the RCD is equivalent to a GFCI = Ground Fault Circuit Interruptor. GFPE = Ground Fault Protection Equipment has higher tolerances and a different purpose: the detection of earth/ground leakage that could damage an appliance but that is insufficient to operate an overcurrent device (e.g. a fuse). The equivalent to an RCBO is a GFCI 'breaker'.
In terms of remotely testing an RCD and thus intentionally causing it to operate (trip), one product I found from an Australian company is the Rapid Test RTTUWF RCD Test Module with Wi-Fi communications, so such devices do exist. This will be safer than a DIY solution to deliberately create imbalance between phase and neutral.
Of course, you'll need extant power to operate any such test device and the network used to trigger it, so it would need to be isolated from the RCD and/or connected to a UPS. It's unclear whether something similar exists for the 110V/60Hz system in Colombia, but the US market may have something designed for this purpose at these voltages.
Remember, the RCD test function is intended to test the device, not to reliably operate it. Its purpose is to verify whether the RCD will operate, which in some cases, it may not. Therefore testing is not a reliable way to de-energize the circuit.
This is the function of an Emergency Power Off (EPO) switch, so that should clearly answer your question of whether you need both - yes, you do. Depending on your purpose for the EPO, you may need a switch or similar device at the power to the UPS and/or from it. APC does offer remote EPO systems for data centers, but this may be overkill.
Comment: A fellow SA expat! Nice. I'm no expert in these matters but I think that RCD is an umbrella term that includes both RCCBs and RCBOs?  Also, I think your description of their operation may apply to the predecessor ELCB devices: iiuc the RCDs detect current imbalances, not voltage. The GFCI device seems to trip at a /much/ lower leakage current than an RCCB: iirc 2mA v 30mA but that GFPEs (or is it GFEP?  I've seen both) can have varying current and time delays, including 30mA/instant. Why are they so expensive though? Your comments about using RCD test and EPO positioning are noted, thanks.
Comment: You're welcome. Typically RCD refers to RCCB but there are so many terms it can be confusing even to the initiated. ELCBs connected to earth and measured actual leakage to the main earth cable, but that doesn't detect leakage through a body that bypasses the earthing, hence my mention of 'current-operated' and difference between L and N voltages under load. It's detecting voltage, but operating based on current. I can't comment on expense in Colombia, maybe import taxes to make up for the illegal drug trade laundering money? ;-)
Comment: Ah, understand. I was looking at US prices for now: finding product in Colombia is difficult at the best of times and local policy is not to give even a hint of the price in case someone might actually want to buy it...  I've now found that GFCI yokes are comparable in price (US anyway) to UK RCDs.  I guess there's limited demand for the GFPEs?
Comment: Is it OK to use a GFCI on a circuit without a ground connection? No idea about code here but it's rare to find premises in Colombia with a functional 3rd earthing pin.  And putting in a grounding rod would mean drilling through a concrete floor. And then I've no idea what the water table depth might be.
Comment: Same here in Mexico - yes, as an RCD measures leakage *from* phase/neutral rather than *to* a ground wire like the old ELCBs did, they don't require an earth connection and will still trip on leakage to earth whether by way of an earth wire, pipes, conductive building materials or a human body, and you'll still see the safety benefits (hopefully not literally)

How can I remotely trip a RCCB?


Received a job offer email followed by rejection email

Question: I received an email from the recruitment manager that my interview was successful however, few days later I received an email from the system that my interview was unsuccessful. I was really happy that I succeeded but I became worried after they sent me a rejection email. I hope it is a mistake. Who shall I ask?
Comment: I disagree with the close. Assuming that you want the job, I would *act* as if you never got the second email, email the recruitment manager and ask about following-up (second interview, offer, when can you start etc.) Worst case scenario, the second email was genuinely, it sucks - keep looking, best case scenario, the second email was in error, you continue the process, Next scenario is that it was a legit email, but because you've followed up, they feel bad and continue the process. Eitherway, you have nothing to loose by acting as if it was never sent.
Comment: There is an existing question almost identical to this one, with an answer people like -- I wrote both, so we'd have it in file. Close as duplicate.
Answer: Talk to the recruitment manager. Only they can clear this up for you.


Parent or master business card document

Question: I have 50 or so business cards to make and they all have the same design and layout with only the text details changing (names, titles, etc).  Is there a way to set up a parent or 'master page' type document that contains the master design with all the individual business cards linked to this parent document.  When the font style or colour or size or layout or whatever is changed on the parent document then it will automatically be applied across the 50 business cards.  Does anyone know a way to do this in Illustrator or Indesign.
Comment: Hi user58694, yes you will want to use InDesign. You will be working with master pages, character styles and paragraph styles. I voted to close your question as your question is either too broad or asking for basic software education.
Comment: Yeah, this is an inDesign-101 question.In addition to the terms above, consider "linking indd document"
Answer: You can also do this in Illustrator.
You just make one business card and write a script that changes the name and exports out a printable copy, then changes the name to the next one on the list and exports out a printable copy, and so on.
The advantage is you don't have to make 50 pages in InDesign, and this would also scale to 10,000 names if you like.
If using AppleScript, you can pull the names from a database.

Parent or master business card document


Silicone tube with three holes, flow rate, pressure

Question: I have a silicone tube -- a saline solution flows in from one end, and then flows out of three holes of equal diameter and equal distance from each other that are along the side of the tube. What can I do to make the pressure at the three holes equal?
Comment: Do you want equal pressure as such, or is your final goal equal flow rates of solution from the 3 holes?
Comment: In principle, it's not possible to get equal pressures at all 3 holes.  Flow is caused by pressure drop.  The pressure at the last hole must be lower than the pressure at the first hole if there is flow in the line.  If you want the same FLOW RATE through each hole, that is certainly achievable, as per the recommendations of @docscience.
Answer: If injected from a single end, and assuming a constant diameter pipe, the pressure decreases linearly along the length of the pipe due to friction.  Therefore equal diameter holes will not yield equal flow rates or pressures.
For equal flow rates:
To control the flow rates, you must control the injection pressure (ex. reservoir with regulator valve).
Specify a desired flow rate (per hole or total) where $Q_\text{total}=3Q_\text{hole}$.  For each hole location along the length of the pipe, $\ell$, calculate the pressure.
$$ P = P_\text{injection}-\frac{8\mu\ell Q_\text{total}}{\pi r_\text{pipe}^4} $$
Next, apply a loss coefficient depending on the cross sectional geometry of the holes (sharp-edged, rounded, etc.) to obtain the pressure at the holes.

$$P_{hole} = P*K_{L}$$
Next, for the desired flowrate, $Q_{hole}$, and known exit pressure, solve for the radius required at each hole:
$$P_\text{hole}-P_\text{exit} = \frac{8\mu\ell Q_\text{hole}}{\pi r_\text{hole}^4} \rightarrow r_\text{hole} = \left(\frac{8\mu\ell Q_\text{hole}}{\pi(P_\text{hole}-P_\text{exit})} \right)^{1/4}$$
For equal pressures:
The only practical way I can think to accomplish this is adding regulator valves to each hole, with an injection pressure high enough to overcome frictional losses to the furthest hole.
Comment: This looks like a good answer, but I'm having trouble understanding it because at least two of the variables are not explicitly defined: what are $\mu$ and $Q$?
Comment: I'm also not sure what $P_\text{exit}$ is. Could you go through and try to clear up the discussion? It looks like you know the right way to solve this so I'm interested in getting it all fixed up.
Answer: I'm guessing the flow rates in your system are slow so the flow is laminar. In that case the flow is described by the Hagen-Poiseuille equation:
$$ \Delta P = \frac{8\mu\ell V}{\pi r^4} $$
where $\Delta P$ is the pressure drop, $\mu$ is the viscosity of your saline solution, $\ell$ is distance along the pipe, $r$ is the pipe radius and $V$ is the volume flow rate. To get the pressure difference between the first and last hole set $\ell$ to the distance between them.
You can't do much about the viscosity of the saline, and I'm guessing the distance between the holes is fixed so you can't change $\ell$. Likewise the volume flow rate $V$ is probably dictated by the experiment. So the only variable under your control is the pipe radius $r$. The good news is that the pressure difference is very sensitive to $r$ because it varies as $r^{-4}$. So if you double $r$ you reduce the pressure difference by a factor of 16.
If the equal flow rate is really critical you could change the pipe geometry to reduce the difference in length between the holes. Something like this:
Comment: Dear John, thank you very much for your prompt response. I am actually working on an artificial tear duct, so the pipe geometry needs to remain the same, however I can change the radii and the length between the holes.
Answer: If your objective is to obtain precise and equal flow rates through the three holes however constrained by serial arrangement you sketched then you need to progressively increase the radii of each duct that are downstream of one another.


Using Morera's theorem to prove analyticity

Question: I have a function $F(x,y)$ which is continuous and analytic on the complement of a certain function $x(y)$. Is it possible to use Morera's theorem to show that it is analytic everywhere? Clearly, this approach can be used if it fails to be analytic on some linear function $x = a y + b$, for example (as far as I can guess, we could complexify $z = x + iy$ and use Morera's theorem by approximating the integrals over circles passing through the line until we showed analyticity everywhere). If $x(y)$ is also continuous (at least on a certain range of interest), could we use a similar method? If I'm wrong, can anyone think of convincing counterexamples?!
Comment: Your terminology is confusing. $F$ is a function on $\mathbb{R}^2$; do you mean to have it be a function on $\mathbb{C}$? What do you mean by the complement of the function $x(y)$?
Answer: If I understand correctly, "the complement of a function $x(y)$"  means the complement of its graph, that is, the set $\{x+iy:x\ne x(y)\}$. You assume that $F$ is continuous in some domain $\Omega$ (possibly $\mathbb C$) and is holomorphic (=analytic) on $\Omega\setminus \Gamma$, where $\Gamma$ is the graph of some continuous function. The question is: does it follow that $F$ is holomorphic in $\Omega$?
(Stated more succinctly: is $\Gamma$ removable for continuous holomorphic functions?)
In general, the answer is no. Here is why.
Let $x(y)$ be a continuous function on a closed interval whose graph $\Gamma$ has Hausdorff dimension $D>1$. Such functions exist: for example, see reference 6 in the Wikipedia article on the Weierstrass function. Pick $1<d<D$. By Frostman's lemma, there exists a finite positive measure $\mu$ with support contained in $\Gamma$ and with the growth bound
$\mu(B(z,r))\le r^{d}$ for all $z\in \mathbb C$ and $r>0$. Define
$$F(z)=\int_{\mathbb C}\frac{1}{z-\zeta}d\mu(\zeta)$$
By construction, the function $F$ is holomorphic on $\mathbb C\setminus \Gamma$. It also tends to zero as $z\to\infty$. Since $F$ is not identically zero, it cannot be extended to a holomorphic function on $\mathbb C$; such an extension would contradict Liouville's theorem.
It remains to show that $F$ is continuous at every point $p\in \Gamma$. Pick a small $\delta>0$ and write
$$F(z)=\int_{B(p,\delta)}\frac{1}{z-\zeta}d\mu(\zeta)+\int_{B(p,\delta)^c}\frac{1}{z-\zeta}d\mu(\zeta)=:F_1(z)+F_2(z) $$
The function $F_2$ is holomorphic in $B(p,\delta)$, and therefore continuous there. For $z\in B(p,\delta)$ the first term can be estimated from above by switching to polar coordinates and integrating by parts:
$$
|F_1(z)|\le \int_{B(p,\delta)}\frac{1}{|z-\zeta|}d\mu(\zeta)
= \int_0^\infty \mu(B(z,\rho)\cap B(p,\delta))\,\frac{d\rho}{\rho^2}
\\ \le \int_0^\infty \min(\rho,\delta)^d \,\frac{d\rho}{\rho^2} =
\int_0^\delta \rho^d \,\frac{d\rho}{\rho^2}+\int_\delta^\infty \delta^d \,\frac{d\rho}{\rho^2}=C\delta^{d-1}
$$
Since $\delta^{d-1}\to 0$ as $\delta\to 0$, the function $F_1$ is continuous at $p$. In fact, the estimate shows that it is Hölder continuous with exponent $d-1$. This relation between Hölder exponent and Hausdorff dimension is not accidental: see this thread and references quoted there.

However, the answer is yes if $x(y)$ is a Lipschitz function. That is, Lipschitz graphs are removable for continuous holomorphic functions. More generally, curves of finite length are removable for continuous holomorphic functions: this a theorem of Painlevé. See Analytic capacity and measure by Garnett (Springer LNM series, 297).


Merge [isolatedstorage] and [isolated-storage] tags

Question: I suggest that we merge isolatedstorage and isolated-storage. Currently there are more questions tagged with isolatedstorage. Though, I don't know which tag should be the main/master tag.
Comment: I'm hoping a few people will weigh in on which direction this synonym should go. Neither tag has a wiki, so we're free in that regard. I'm leaning towards making [isolated-storage] the canonical tag, even though the non-hyphenated version currently has more usage.
Comment: No real association with the topic, but I think [isolated-storage] looks better.
Answer: isolatedstorage probably exists because the namespace is called System.IO.IsolatedStorage. The concept is referred to in MSDN, however, as "isolated storage" (not even a proper noun!), which of course aligns with the tag, isolated-storage.
When presented with choices like these, I usually favor the name or title that is used in writing over the code identifier, so I'd go with the hyphenated tag. Either way, when the tags are synonymized, only one tag will actually be shared by and displayed in questions, whichever is entered in the Tags field.
Also since Bill is asking that a few people weigh in, we'll hold off on doing anything for the moment.
Comment: Does the *concept* of "isolated storage" come up in other languages or frameworks?
Comment: I agree with this.  If you look at the casing of `IsolatedStorage`, it's intended to be two words, there's no reason to *not* hyphenate them in the tag.
Comment: @ChrisF: No I don't think so.


BPSK consecutive same symbols

Question: I have a question regarding BPSK. If we want to modulate the bit stream $[0, 0]$ with $T_\text{ bit}=0.25 \text{ sec}$ and the carrier frequency of the cosine that carries the BPSK signal is $2\ \rm Hz$ then the resulting waveform would be the one with the discontinuity or would the signal continue as it is until it reaches $0.5\ \text{sec}$? See pics below, it makes sense to me that we would have a discontinuity at $0.25\ \text{sec}$ because otherwise the receiver which samples the transmitted signal at every $T_\text{bit}$ would confuse the second zero as an 1:
Comment: Are you sure it makes much sense to have a symbol rate greater (4 Hz) than the carrier (2 Hz) for BPSK?
Comment: That is what is given to us
Comment: then what is given to you makes no sense. The general assumption is that the carrier frequency is much larger than the signal bandwidth, and that's not the case here.
Comment: I understand that but what i need to know is whether the graph would have a discontinuity, as i understand from the receiver block diagram it samples the signal for every Ts so if there is no "break" it would guess the bit to be 1 not 0.
Comment: We can assume for the sake of the question just that carrier frequency is not a multiple of the bit rate and we would still have the same question.
Answer: The canonical baseband version of BPSK is that we wish to transmit a sequence $\{a_k\}$ of bits ($0$ or $1$) at a rate of $1$ bit every $T$ seconds using a pulse $g(t)$ of duration $T$ and so the transmitted baseband signal is
$$s_{\text{baseband}}(t) = \sum_{k=-\infty}^\infty (-1)^{a_k}g(t-kT).$$
This is a sequence of nonoverlapping pulses of the form $\pm g(\cdot)$ spaced $T$ seconds apart. If, for example, $g(t)$ has value $1$ for $t \in [0,T)$, then $s(t)$ is a sequence of rectangular pulses of duration $T$
with the $k$-th pulse lasting from $t=kT$ to
$t=(k+1)T$. Let's use this specific $g(t)$ for the rest of this answer. Note that $s_{\text{baseband}}(t)$ has value $0$ or $1$ for all $t$, and that it changes from one value to the other at times tenant are multiples of the bit duration $T$.  Some elementary books on digital communication extend these notions to the passband signal too, saying that the passband BPSK signal during $[0,T)$ is of the form (say) $\pm g(t)\cos(2\pi f_ct)$ (where $f_c$ is the carrier frequency) and so during $[T,2T)$, the passband BPSK signal is just this passband RF burst delayed in time by $T$ seconds. That is, such texts take the passband BPSK signal to be
$$s_{\text{passband}}(t) = \sum_{k=-\infty}^\infty (-1)^{a_k}g(t-kT)\cos(2\pi f_c(t-kT)).$$
Such a re-setting of the carrier phase to $0$ every $T$ seconds leads to discontinuities such as seen in the OP's first figure which correspond to $a_0=a_1 =1$.
In practice, and even in more advanced textbooks on digital communications, the BPSK passband signal is of the form
$$s_{\text{passband}}(t) = s_{\text{baseband}}(t)\cos(2\pi f_ct) = \left(\sum_{k=-\infty}^\infty (-1)^{a_k}g(t-kT)\right)\cos(2\pi f_ct)$$
which makes the modulation aspect very clear: there is an oscillator that is producing the carrier signal $\cos(2\pi f_ct)$, and this is being modulated by the baseband BPSK signal. Sure looks like amplitude modulation to the untrained eye, but it is indeed phase modulation, because the baseband signal has value $\pm 1$ and since $\cos(2\pi f_ct-\pi)=-\cos(2\pi f_ct)$, we can write
$$s_{\text{passband}}(t) = \cos\left(2\pi f_ct - \pi\sum_{k=-\infty}^\infty a_kg(t-kT)\right)$$
where that inner sum has value $1$ or $0$ for all $t$ and so $s_{\text{passband}}(t)$ is a sinusoidal signal whose phase at all times is either $0$ or $\pi$, and the phase can flip from $0$ to $\pi$ or vice versa only at $T$ second intervals. With $a_0=a_1=1$, the phase remains at $\pi$ during $[0,2T)$ leading to the second plot provided by the OP.
Comment: @user67081 I agree with regard to RRC signals which technically do both phase _and_ amplitude modulation, but at the level of what the OP Is asking about (and he didn't define what he understands BPSK signaling to be doing), it is best to keep things simple and not clutter up the explanation.
Comment: Is the last equation missing a $pi$ in front of the sum? Also - one thing I think people find confusing (at least I have before) - I know you noted at the top that you're using a pulse g(t) =1 over  [0,T) for your answer, but the final equations showing how it is actually phase modulation does not hold when a different g(t) is used. This is often done, for example when doing RRC filtering. I would argue this is true of most real-world implementations of BPSK (or at least what we tend to call BPSK) and its one thing that's not really well spelled out in textbooks.  Interested in your thoughts.

BPSK consecutive same symbols


Black Market Resilience

Question: In many countries drugs like marijuana are being increasingly legalized or at least decriminalized. In such circumstances, you would expect the previously illegal or bootleg marijuana producers to disappear. Yet, even under legalization, a black market remains. Is this a transitory phenomenon or are there reasons to expect the black market to remain in some form?
Comment: John Stossel did a recent report covering this topic  https://www.youtube.com/watch?v=tP3fs_AuJHc&t=55s Basically as long as the government screws up while trying to overregulate a market black market will persist
Answer: My syllogism is the following:

Going from a paperless, tax-exempted, although illegal
business, to a taxed, legal business saturated with paperwork must be
a bad bargain for at least a percentage of existing dealers. This
means that there are costs to initiating and maintaining a legal
business that are not present when this business is run in secrecy.

This is especially true for well-connected and established suppliers who are efficient in their price setting and production volumes. It also is a more permanent reason for a black market to persist, and it seems that only legal dealing marijuana was subsidised by the government, would it compete with the advantages of running it in secret.

Because owning and dealing marijuana is legal in one country, it does not mean that all marijuana used is produced locally - most is imported from places where it is still illegal (and highly profitable). Suppliers might be getting a cheaper product if they import it illegally than they would if they bought it from within their borders.

This would mean that no matter the legalisation of marijuana in one country, barriers still exist for the market to become fully legal.

Costumers might not be willing to transact in a transparent fashion when it comes to a stigmatised substance such as marijuana.

Thus, even if the supply side of the market becomes completely normalised in the passage of time, there might still be demand-side barriers for it to run in compliance with the law.

Black Market Resilience


Height of deer fencing

Question: I live on the Washington coast in an area with a large population of quite tame deer.  There is a 6 foot wooden fence along once side of my back yard.  The deer have never jumped over this fence, but they can easily go around.  Along this fence I planted many small trees/shrubs/etc that were supposed to be deer-resistant.  Ha!  Anyway, if I put six-foot tall fencing around this area attached to the wooden fence at the ends, 4-5 feet out from the wooden fence, would the fact that it is that close to the wooden fence keep them from jumping over the deer fence?  A fence higher than that seems like overkill for such a small area.  I mainly just want to give my trees a chance to get taller.   Thank you!
Comment: Hi Anne, the real motivator for deer is how hungry they are.
Comment: Hi Anne. I live in an area with extraordinary deer pressure where they eat things normally considered deer resistant. We have put all kinds of deer fencing in all kinds of places, and have seen first hand what works and where. Your original idea of putting the 6' deer fence approximately 5' from the wood fence will work just fine. Deer will not jump into such a confined space - especially if there are plants occupying some of it. The risk of going any closer is that the deer may be able to reach your plants through the fence or as plants grow through the fence.
Comment: This was my original rationale and I think it does make the most sense.  I'll just have to hope that the deer aren't smarter than I am :/
Comment: Deer will not jump a fence if they can not see the other side, so a solid 6 ft wood fence stops them but they easily go over an 8 ft wire fence.
Answer: I think if I placed the deer fence closer to the wooden fence than I had originally planned -- maybe 3 feet rather than 5 -- that the deer wouldn't be able to jump in.  That would enclose the trees but not some of the shrubs like rhododendrons, which the deer nibble a tiny bit on but don't really ruin.
Comment: I think this is a sound plan. Giving them a smaller, more constrained landing zone might make them move on to easier pickings. But, again, the motivator is hunger. Hard to imagine a shortage of forage in your part of the country.
Comment: You can give it a shot, but don't be surprised if deer suddenly start jumping your fence. If there isn't much food in the area, there is no doubt they will jump your fence. The best option is to build a cage around the trees.

Height of deer fencing


How can I specify an arbitrary sort order without grouping?

Question: I've been tasked with cleaning up a report that shows a summary of ticket sales by payment method used. One of the requirements is that I put the "Cash/Check" category on the bottom of the list, with all of the different credit cards above it. Using the group options to set a specified order won't work, because all of the payment types other than Cash/Check can change based on the client's specifications, so I can't create individual groups for each payment type and then put them in order. What I need is a way to put an ordered list of known payment types at the bottom or top of the list, followed by an unordered (or at least not explicitly ordered) list of unknown payment types. I haven't been able to find a good way to do this on the internet where there are unknown items involved. Any thoughts?
Comment: Add some sample data and how you would like to see it sorted in the output
Answer: Either add an independent sequence field or sort by your value with a prefix added to your targeted value that ensures it's at the bottom of the list.
In this example, I want the resDesc value sorted alphabetically, unless the resSupCode value = 0, in which case I want it sorted first, so I append a space to the title:
<code>if {vw_rpt_waitlist.resSupCode} < 1 then
    formula = Switch ({vw_rpt_waitlist.resSupCode} = -1, "Total, No Residence Listed", _
                      {vw_rpt_waitlist.resSupCode} = 0," " + {@xtab_title} + " Total")
else
    formula = {vw_rpt_waitlist.resDesc}
end if
</code>
Answer: Would it work for you to create a formula that returned 1 for the first one in the list, 2 for the second one in the list, and so on until you return 8 (or 12, or 1000, or whatever) for everything else, and then tell Crystal to sort on that formula instead of the payment type field?
Answer: Embed the cash/check query in a sub-report.  Add it the Report Footer section.


Is the phase difference between recorded sounds from left and right ear the same as the phase difference between their HRTF?

Question: Pardon my ignorance if my question is silly. Lets say I did a binaural recording and found the phase difference between right and left channel. If the recording was done in anechoic chamber, where there is no reverberation, can I say that this phase difference is same as the phase difference between their HRTFs which they were filtered by (on their way from speaker to my ear)?
Comment: Although a technicality (i.e., may not have significant perceptual implications), I shall simply add that @OlliNiemitalo's answer is correct provided that the two microphones you use to make the recording introduce exactly the same phase distortion.
Answer: Consider a signal with a particular frequency at phase $\alpha$. Passing this through the two filter paths changes the phase of the frequency to $\alpha + L$ and $\alpha + R,$ where $L$ and $R$ are the values of the phase frequency responses of the two HRTF filters at the particular frequency. Yes, the phase difference $(\alpha + R) - (\alpha + L)$ is equal to $R - L,$ which you call more simply the "phase difference" between the HRTF's.


Why must the belt in a van de Graaff generator be insulating?

Question: If it were conducting then it would not be required to be constantly driven over the pulley; the positive charge gained at the bottom could just flow directly to the large sphere.
Comment: The body of your question sounds like you are trying to post and answer to the title of your own question... Try to write and format your questions in a way that they are easy for other users to read and understand. Put some effort into it. You will get better answers.
Answer: If the belt is not insulating, any charge on the terminal will just flow back to ground, so you can't build up charge on the terminal and it will not rise in potential.  The point of a Van de Graaff generator is to physically move charge against the electrical gradient, and you can't do that if the belt lets it slip away.
Now, you can instead use the Pelletron system from National Electrostatics instead of the original High Voltage Engineering (the company Van de Graaff founded to make accelerators) rubberized belt.  The Pelletron system uses chains of 'pellets', where each pellet is a plastic cylinder plated with metal on the circumference. The links are also plastic, so the chain is insulating along them. These suffer less degradation of the charge carrying capacity of the chain. Belts would wear and develop bald spots that wouldn't carry charge, so the terminal voltage would not stay constant.
Comment: In that case the ground the terminal will just acquire the same potential, and the belt will have no net charge on it, is that right? (So now more charge flows to the terminal.)
Comment: I believe that you are still fuzzy on how a Van de Graaff generator works.  It mechanically moves charge from low potential to high potential, effectively across a capacitive gap, to generate a voltage that is proportional to the charge moved. If the terminal acquires the same potential as ground, well, it isn't at potential any more. There are purely electrical ways of generating high voltages, such as a Cockroft-Walton style supply.


Decorrelating Two Time Series

Question: Suppose that I have two time series $\{x_1, \ldots,x_t\}$ and $\{y_{1+k}, \ldots,y_t\}$ which have some level of correlation over an overlapping time period. What techniques can I use to decorrelate these two time series? Perhaps multivariate AR models or something of the like?
Comment: What do you mean by "decorrelate", and what is your ultimate goal? By the way, multivariate AR is commonly known as vector AR, i.e. VAR (there is a tag for it here, too).
Comment: By "decorrelate," I've assumed you really mean *whitening. * This Wiki article describes it this way, "A whitening transformation is a linear transformation that transforms a vector of random variables with a known covariance matrix into a set of new variables whose covariance is the identity matrix meaning that they are uncorrelated and all have variance 1. The transformation is called "whitening" because it changes the input vector into a white noise vector." https://en.wikipedia.org/wiki/Whitening_transformation    Is this what you mean?
Comment: Cross-correlation statistics between two time series are often (always) misleading . Take a look at http://empslocal.ex.ac.uk/people/staff/dbs202/cat/stats/corr.html for more ....
Answer: Depending on what you want to do, you can build an ARMA model or similar to take into account the correlation in the your predictions.
If you are simply trying to use the data for something else that assumes there is no correlation, you can try to either transform the data sets or, perhaps with more success, resample the data sets at a more coarse frequency such that the correlation disappears.
You can create a cross-correlation plot (similar to the one below) to check for correlation between two time series. Any insignificant correlation you can ignore, as well as most correlations at higher lags (depending on how much data you have; calculating the correlation with a few data points can create spurious significant results).

Hope that helps!
Answer: What is the purpose of decorrelating?
Maybe you may want to simulate them without correlation, if that is the case, you should simply ignore the other while you study X or Y.
Comment: This does not constitute and "answer" to the OPs question and, as such, should be treated as a comment.

Decorrelating Two Time Series


How can I achieve conditional page breaks in SSRS 2016

Question: I am using SSRS 2016 and Report Builder. I need the page breakinging with a group to be conditional on the value of a parameter. Does anyone know if this is even possible?
Comment: Thanks, I may try that if another solution doesn't appear.
Comment: I used to place "invisible" (no border/transparent background) text boxes or rectangles where I needed page breaks and then add the "page break before" or "page break after" on that invisible object.  This was in SSRS 2008 so not sure if it's still possible.
Answer: Another workaround, which seems to work quite nicely - place a parent group of the group you want to selectively break on, then in Group Properties for that, group on a derived expression of either the group field, or a fixed value. And then tick the box for that grouping as per your screenshot.
e.g. Assuming a parameter called "BreakPages", and a grouping on a field called "MyGroupField", you group on:
<code>=iif(Parameters!BreakPages.Value="Y", Fields!MyGroupField.Value, "None")
</code>
You don't need to display any fields in this special group, it'll simply use the page break setting as per your requirements..


How do I set up my Yongnuo RF-603II trigger and Yongnuo YN-568EX flash?

Question: I have a Nikon D5000 with one Yongnuo RF-603II trigger. How can I use my Yongnuo YN-568EX flash as an external flash? What settings do I use?
Comment: And http://photo.stackexchange.com/questions/56682/why-does-the-yn-565ex-need-a-radio-trigger-with-the-yn-560-tx
Answer: If you want to use the RF-603II to trigger the flash as a transmitter, return/sell the YN-568EX flash, and get a YN-685 or YN-560III or IV, or if you want to use it as a receiver on the flash, buy a RF-603, RF-603II, RF-605, or YN-560-TX to act as the on-camera transmitter.
The YN-568EX has no built-in radio receiver. And to get a radio connection, you need both a transmitter and a receiver. The YN-568EX only has optical sensors in it to be used as a CLS slave in Nikon's proprietary wireless system (which requires a D7000 or above, or a commander flash unit on the hotshoe), or "dumb" optical triggers which can be set off by the D5000's pop-up flash (S1 = if the popup is in M mode; S2 = if the popup is in iTTL).
If you do get another RF-603II-compatible trigger to use as the on-camera transmitter, make sure that the YN-568EX is out of all the slave modes, and in M mode. The RF-603II is a manual-only trigger, so you can't use TTL/HSS, or remotely change the power on the flash from the camera.  If you want these features, you'll have to consider the YN-622N triggers, and upgrading your camera body to one that can do HSS (FP flash).
You need a flash with a built-in radio receiver that understands the RF-603II.  The two speedlight models I listed above both have this capability.  Otherwise, you have to add a radio receiver unit that speaks the same protocol as the RF-603II onto the foot of the YN-568EX.
See also:

Why does the YN-565EX need a radio trigger with the YN-560-TX?
What are the Yongnuo flash naming conventions?


eth0 with static ip gets shutdown after dhclient fails

Question: I have a Nvidia Jetson TX2 SoC in an Connecttech Astro carrier board running Ubuntu 16.04.  The carrier has two Gigabit Ethernet ports which I would like to configure with static IPs.  In system settings -> network:
Wired Connection 1 ->IPv4 settings:
manual
IP:192.168.22.148
Mask: 24
Default Gateway: 192.168.22.1
Wired Connection 2 ->IPv4 settings:
manual
IP:192.168.1.148
Mask: 24
Under normal operation this TX2 is connected to another TX2 and some other components via a simple unmanaged switch. All components have static IPs set so they can operate without a dhcp server.  When the TX2 is powered on everything works as it should but after 5 minutes, eth0 (wired connection 1) disappears. Looking at the syslog, it appears this is because dhclient doesn't get a reply from a DHCP server (because there isn't one connected) which triggers the interface to be shutdown.  The avahi-daemon takes over eth0 and tries to configure it but fails.
I see the timeout in /etc/dhcp/dhclient.conf is set to 300 seconds.
I am trying to figure out why dhclient is doing anything since the interface is set to manual with a static IP.
I also configured the static IP via /etc/network/interfaces:
auto eth0
iface eth0 inet static
address 192.168.22.148
netmask 255.255.255.0
gateway 192.168.22.1

auto eth1
iface eth1 inet static
address 192.168.1.148
netmask 255.255.255.0

/etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

[ifupdown]
managed=false

but this did not make a difference.  So my question is why is dhclient making DHCP requests for eth0 when it's configured as static? What is shutting eth0 down when it fails? What's the right way to fix this?
Couple other tidbits of information, 1) if a router or other dhcp server is attached, everything works perfectly.  2) I had a similar hardware configuration with a Jetson TX1 running Ubuntu 14.04 that worked fine.
This post is not helpful: https://askubuntu.com/questions/459140/why-dhclient-is-still-running-when-i-choose-static-ip
Answer:
Ensure that dhclient is not envoked from any start-up scripts or are running in the background. (ps auxw | grep dhclient). You can kill it with: pkill -f dhclient.
There is several network related services and wrappers in Ubuntu, so can be invoked from an app such as network-manager. If you run a headless server I'd recommend you disable the network-manager and rely on the native networking.

sudo systemctl disable NetworkManager.service
After applying this changes, I would restart the machine for good measure, to ensure that there is no services remaining that invokes dhclient.
Hope this helps!


Was Ravan actually a big devotee of Lord Shiva?

Question: Was he actually a huge Shiva bhakt or was it exaggerated to make him look good?
Comment: What makes you say this?
Comment: There is no proof of him being a Shiv bhakt. These are later Interpretations or even Propaganda to counter the Ram movement.
Comment: @Wikash_ nothing against Ravan but little bit of Valmiki Ramayan, I have read shows him in very negative light so I am curious if he was actually Shiv bhakt or people romanticized him. Just curiosity
Comment: He was actually a Shiv bhakt.
Answer: No, he was NOT a devotee of Lord Shiva at all. It's a made up story based on some later Interpretations or may be even propaganda.
More details here

Far from any "Shiva Bhakti", Ravana actually battles with Rudras on a
number of occasions.
there is ONLY one instance in the entire Valmiki Ramayana, that too in
Uttarakanda (7.31 CE), that Ravana worships Shiva. There is NOTHING
anywhere else to even remotely suggest "Shiva Bhakti". There is no
'Shiva Tandava Stotram' anywhere in the Valmiki Ramayana.

Raavan didn't even know who Shiva was:

"Hearing Nandi's words, Ravana, with his earrings trembling in his
wrath, his eyes red with fury, leapt down from the Pushpaka Chariot
and approaching the foot of the peak, demanded:—
"'Who is this Shankara?'
Answer: What is the benefit of "romanticizing" an antagonist other than teaching people that look, no matter how big of a worshipper you are, how much knowledge you posses, how powerful you are - nothing matters in the end when you have stepped away from the path of Dharma and Maryada.
As per the many interpretations of Ramayana, one can definitely say he was a big Shiv bhakt, some would argue even the biggest. There's the story about him lifting the Kailash Parvat to demonstrate his power to Shiva, if he was not a bhakt then why would he do that? Then there's the live example of his bhakti as Shiv Tandav Stotram, why would he compose it for no reason?
Now it is hard to go back thousands of years in the past, and in yugs and find out the truth, but from what we read, what we hear, he definitely was a big Shiv bhakt, no doubt, and not only that but he was also a great scholar of the Vedas, he had immense knowledge, and the very essence of his story is that no matter how powerful or knowledgeable you are, adharma always comes to an end, and that arrogance has no place.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
Comment: Can you post some links as evidence to the claim "As per the many interpretations of Ramayana, one can definitely say he was a big Shiv bhakt, some would argue even the biggest. There's the story about him lifting the Kailash Parvat to demonstrate his power to Shiva" ? These episodes seem to be modern myths than in any of the actual texts


Can an  tag resize when a  inside is rendered?

Question: As you know, an HTML
 element can have a lot of geometry variation for width and height of cells and the whole table overall.  The browser does a lot of work re-sizing cell height and width to fit "nicely." in the available window size.  A huge range of variation exists in table geometry, of course.
When an <object> contains an HTML
, that former tag can specify width="100%" (or some fixed pixel width), which render pretty well for nominal cases.  However if the table height as-rendered is rather large, setting height="100%" doesn't yield a very tall table, and it's not dynamic as the browser window changes.  And using fixed pixel height= is unhelpful if you don't know the as-rendered height in advance.  If you're relying on the browser to arrange the cells in its default behavior.
Does anyone know any tricks to get <object> to better respect the dimensions of an HTML
 inside it?  I can picture the <object> inquiring its contents for height or width attributes on a root element, e.g. SVG markup has these and resizes the containing <object> smartly.  Would it help to fake out <object> by including these attributes in the
 markup?  (I've tried, but no joy in limited attempts).
I wish <object> were smarter about this, but apparently it's not.
Answer: No.
You can use a seemless iframe instead (although this is a bleeding edge feature with limited browser support at present).
Comment: Tried a few things on that, and no joy.  It seemed like I might have to get into some Javascript extensions to alter the `` attributes myself, by brute force.  Arghhh, unnecessarily complex, why can't the darn tag do that itself!!


Can Session storage / local storage be disabled and Cookies enabled?

Question: For most modern browsers, is it possible to have session or local storage disabled while cookies are enabled? Or does the disabling of cookies also, automatically, disable the use of session / local storage?
Comment: @MagnusKarlsson - My question is clear and I didn't say I was trying to do anything. I am simply asking about the relationship between a user disablling cookies and, whether by doing so, session or local storage disabled too.
Comment: I'm not following what you are trying to do? What is your use case? Why do you want to turn off storage in browser when using cookies? One does not interfere with the other.
Comment: Well not that clear since your comment actually clarified what you are asking for. And my question was to know if you had any special use case which could be solved with Chromium or other browsers, but I guess not then.
Answer: Technically speaking, cookies and the Web Storage API are different things, but a common user probably does not know the difference, nor need to. A common user has, however, heard about security concerns with cookies. He may also have heard advice to regularly clear cookies or disable them altogether. And so, a common user expects a function that says "Disable Cookies", but actually means "Don't let websites persist data on my computer".
I believe that is why most browsers continue to provide the familiar function of disabling "Cookies", but of course do more than that under the hood in order to fulfill what they think is the actual user intent.
For now, the behaviour is browser-dependent. Disabling cookies on each of these browsers disable the following:

Chrome: cookies, localStorage, sessionStorage, IndexedDB
Firefox: cookies, localStorage, sessionStorage
IE: cookies only

I do think that for the sake of precision and flexibility, browser vendors should tweak their implementation to have a basic option "Don't let websites store data on this computer" which disables cookies and all persistent storage mechanisms, as well as "Advanced Settings" functionality to individually disable various storage mechanisms.
Comment: Hi, thanks for your info. by the way, where do you find the behavior of each browser accordingly?
Answer: All I've been able to find is § 6.1 of the W3C Web Storage Specification:

Treating persistent storage as cookies
If users attempt to protect their privacy by clearing cookies without also clearing data stored in the local storage area, sites can defeat those attempts by using the two features as redundant backup for each other. User agents should present the interfaces for clearing these in a way that helps users to understand this possibility and enables them to delete data in all persistent storage features simultaneously.

Browsers "should" enable simultaneous deletion, but there's no recommendation on separate toggles for local storage and cookies.
That said, in IE 11, I'm able to disable DOM storage but enable cookies.  Conversely, disabling cookies has no effect on DOM storage. In FF & Chrome latest, disabling cookies seems to also disable DOM storage.
Answer: If you disable the cookie , then local storage will not work. I Just tried out .
Try the following steps , to check it out
Google Chrome
<code>    step 1 :
    Select the Chrome menu icon Chrome menu.
    Select Settings.
    Near the bottom of the page, select Show advanced settings.
    In the "Privacy" section, select Content settings.
    Select Block sites from setting any data.
    Select Done.

    Step 2 : Open browser console and type localstorage.name="test". This will throw below error

    Uncaught DOMException: Failed to read the 'localStorage' property from 'Window': Access is denied for this document.
        at Error (native)
        at <anonymous>:2:1
        at Object.InjectedScript._evaluateOn (<anonymous>:895:140)
        at Object.InjectedScript._evaluateAndWrap (<anonymous>:828:34)
        at Object.InjectedScript.evaluate (<anonymous>:694:21)

    Step 3 : now enable cookie and try it out . Local Storage will work
</code>
FireFox:
The same I tested in Firefox  and it works the same way .
Try the steps below:
<code>Step 1:
    Click the menu button  New Fx Menu and choose Options.
    Select the Privacy panel.
    Set Firefox will: to Use custom settings for history.
    Now disable accept cookies from site

Step 2:
Open browser console and try localstorage.name="test" . This will fail as below
SecurityError: The operation is insecure.

Step 3:
Now enable cookie and try it will work.
</code>
So without cookies enabled localstorage will not work on chrome and firefox.
Comment: Thanks bishop .  But it's still difficult to consider IE as modern browser :P . So I did n't do test on that
Comment: I appreciate the details for Chrome and Firefox.  Unfortunately, your first sentence ("If you disable the cookie , then local storage will not work.") is true only for certain browsers.  In IE, for example, disabling cookies disables *only* cookies: you have to separately disable local storage, deep in the advanced settings' check-box hell.


Differences between capabilities of QGIS and ArcGIS in 3D modeling

Question: I am learning to use QGIS and ArcGIS for Desktop.
What are the differences between the capabilities of QGIS and ArcGIS in term of processing & representing 3D model?
Answer: I've used both and they have similar capabilities, though the tools in ArcGIS are more readily accessible and better presented in my opinion. However, the biggest difference is cost.  QGIS is of course free.  ArcGIS needs 3D Analyst which represents an additional cost on top of the basic licence.  Tools similar to those in 3D analyst can be found in the QGIS processing toolbox courtesy mostly of GRASS and SAGA.  In my opinion, the visualisation tools (ArcScene) are easier to use in ArcGIS than QGIS (NViz and others) and slightly more sophisticated, but I consider both limited in this department and when I need to do 3D visualisations I use other 3D software (use the right tool for the job!).
I wouldn't call either QGIS or ArcGIS tools truly 3D though, more 2.5 D, though GRASS (in QGIS) does have some voxel calculations which possibly gives it the edge over ArcGIS (the last time I used it ArcGIS did not offer that).  For other QGIS 3D capabilities, have a look at this article.
I think that if these are your choices, it comes down to cost.
Comment: Thanks for the comment. May I know what is the 3D sofware you are using?
Comment: Blender 3D.  It has a python API so it is easy to incorporate GDAL.  I wrote some plugins for it a while ago, but there are some useful ones available through the Blender community, which I now use for getting data into Blender instead of maintaining my own..  All the analysis side of things I do using QGIS/GRASS


Is there use for the Scroll Lock button anymore?

Question: The scroll lock button seems to be a reminder of the good old green terminal days. Does anyone still use it? Should the 101 button keyboard become the 100 button keyboard?
Answer: In Excel, if you turn on scroll lock, using the arrow keys scrolls the spread sheet instead of changing the cell the cursor is in.
Answer: In many KVM situations, double-hitting scroll lock with bring up the machine selection screen.
Answer: I use it all the time on Unix terminals. It is quite handy when something catches my eye when I'm tailing a log file.
Answer: Microsoft Excel uses Scroll Lock to allow you to scroll the spreadsheet around with the arrow keys without changing the active/selected cell -- in line with the Scroll Lock key's original intent.
Answer: In Microsoft Excel, Scroll Lock allows you to scroll a spreadsheet with the arrow keys without moving the active cell pointer from the currently highlighted cell. In Quattro Pro, another spreadsheet program, Scroll Lock works in a similar manner, although in contrast to Excel it's not possible to scroll the active cell pointer completely off the screen.
Other programs use Scroll Lock for special functions.
Answer: Scroll lock (at least the LED for it, anyways) is used along with the caps lock and num lock LED's to provide diagnostic error codes when troubleshooting hardware issues on Dell laptops. This is quite useful when troubleshooting display problems that might prevent diagnostic messages from being read off the screen.
Answer: It looks mostly dead:
http://en.wikipedia.org/wiki/Scroll_lock
I don't remember the last time I used it...
Answer: If you happen to have some legacy MS-DOS games around, it might be useful ;-)
Answer: One of the visualization plugins for Winamp (A media player) uses scroll lock to prevent the visualization from rotating visualizations every x seconds
Answer: In Synergy you can lock your mouse to the current screen. Very helpful when you want to share a mouse with a PC on the other side of the room.
Answer: Well, that's yet another key to be used with AutoHotkey... (or other keyboard shortcut managers).
Answer: Since it is connected to the LED, some clever folks have added code to make it flash (e.g. scroll lock on/off/on/off) at a given interval as a notification for new email messages (or similar)
This can be "cool" if you have a laptop, that is closed (or the screen is sleeping)... you just see if the light is blinking.
Answer: I use it all the time, with the purpose for which it was made. For a variety of things.


How to write to a tmp/temp directory in Windows Azure website

Question: How would I write to a tmp/temp directory in windows azure website?  I can write to a blob, but i'm using an NPM that requires me to give it file names so that it can directly write to those filenames.
Answer: Are you using Cloud Services (PaaS) or Virtual Machines (IaaS).
If PaaS, look at Windows Azure Local Storage. This option gives you up to 250gb of disk space per core. Its a great location for temporary storage of information in a way that traditional apps will be familiar with. However, its not persistent so if you put anything there you need to make sure will be available if the VM instance gets repaved, then copy it to Blob storage. Also, this storage is specific to a given role instance. So if you have two instances of the same role, they each have their own local storage buckets.
Alternatively, you can use Azure Drive, which allows you to keep the information persisted, but still doesn't allow multiple parallel writes.
If IaaS, then you can just mount a data disk to the VM and write to it directly. Data disks are already persisted to blob storage so there's little risk of data loss.
Answer: Just from my understanding and please correct me if anything wrong.
In Windows Azure Web Site, the content of your website will be stored in blob storage and mounted as a drive, which will be used for all instances your web site is using. And since it's in blob storage it's persistent. So if you need the local file system I think you can use the folders under your web site root path. But I don't think you can use the system tmp or temp folder.


Attribute table is missing in raster after using extract by mask tool

Question: Every time I use the extract by mask tool, the rasters that are created don't have an attribute table (i.e it's greyed out). Does anyone know what is causing this and why these rasters essentially no longer have any values associated with them? Is there a way to get around this issue? I am using ArcGIS for Desktop.
Comment: Are you using ArcGIS for Desktop or something else? There is an **edit** button you can use to clarify your question with this detail.
Answer: Since extract by mask creates an entirely new raster, I wouldn't necessarily expect it to preserve any attribute table associated with the original. The actual values of the new raster should be present and match the original. If using this tool (or similar tools which generate a new raster) you may need to use the Build Raster Attribute Table tool and then join/export or join field the original table to the new one. More information can be found in the help files for Raster dataset attribute tables.
As suggested at Preserve attribute table while using Extract by Mask in ArcGIS you might use the Clip tool under Raster Processing instead, which should do essentially the same thing and preserve the attributes. Note it may preserve all attribute values from the table, not just those present in the extracted/clipped area.


Are the foods in the Star Wars Universe the same as ours?

Question: Are the foods in the Star Wars Universe the same as ours? Do they have strawberries or potatoes or something? I know that they might have some food other than the food that we also have, but I'm wondering if they have any food like ours.
Comment: They have chocolate and calamari
Comment: Don't forget Blue Milk
Comment: They have our tupperware
Comment: Oh, drat, what's the name of that one fruit that appears in episode II?
Comment: They mostly have their own food with local ingredients (eg they have meat, but that's not beef!). However I remember about Luke drinking hot chocolate (an exotic beverage Lando gave him) in Thrawn's trilogy.
Comment: @user867 I think it was a pear... ?
Comment: @Petersaber:   Was that a joke?  (http://i173.photobucket.com/albums/w56/STWRSChronicals/Races/MonCalamari.jpg)
Comment: Nerf nuggets in rancor sauce. THAT.
Comment: @ThePopMachine that's the joke.
Comment: Oh yeah, they've got [Coca-Cola](https://starwars.fandom.com/wiki/Coca-Cola), [Dasani](https://starwars.fandom.com/wiki/Dasani), [Goldfish](https://starwars.fandom.com/wiki/Fish_Crackers), you name it.
Answer: Examples of foods specifically mentioned in Star Wars (the original trilogy):
Root Leaf Stew
This is what we see Yoda and Luke eating on Dagobah.  While the script says that Luke is reluctant to eat it, but takes a sip and is surprised to find it rather pleasant, in the actual movie, he is clearly disgusted by it.
Here's what the script says:

CREATURE
Patience! For the Jedi it is time to eat as well. Eat, eat. Hot. Good food, hm? Good, hmm?
[With some difficulty in the cramped quarters, Luke sits down near the fire and serves himself from the pot. Tasting the unfamiliar concoction, he is pleasantly surprised.]
LUKE
How far away is Yoda? Will it take us long to get there?
CREATURE
Not far. Yoda not far. Patience. Soon you will be with him.
[Tasting food from the pot]
CREATURE
Rootleaf, I cook. Why wish you become Jedi? Hm?

But here's how the scene appears in the finished film (note Luke's grimace after tasting the stew):

From the Wookieepedia entry on Root Leaf Stew:

"Eat, eat. Hot. Good food, hmm?"
―Yoda, while serving Luke Skywalker rootleaf stew
Rootleaf stew was a favorite meal of Jedi Master Yoda during his exile on Dagobah. It was a staple of his diet, supplemented by yarum seeds, mushroom spores, galla seeds, and sohli bark. Yoda prepared rootleaf stew the evening that he met Luke Skywalker.
In an unusual promotional campaign for the Empire Strikes Back radio dramatization, National Public Radio hired Craig Claiborne, a renowned chef and food critic, to create a version of rootleaf stew that could be made with ingredients originating from Earth. The recipe was published in newspapers and magazines across the United States.

[Note:  As some of you may know, I'm a chef in real life, and although you have probably never heard of Craig Clairborne, I can assure you that he was a very big deal.  If you've ever eaten the Japanese beef and scallion rolls in a sweet mirin, sake, and soy based sauce, known as Negamaki (or Negamyaki), you can thank Craig Clairborne for that.  He invented it.  He was friends with Julia Child, Jacques Pepin, and James Beard, and was the most highly regarded food critic of his day.]
The Rations Luke is eating when Yoda shows up (and which Leia is eating when Wicket shows up):

It always seemed to me that the most prominent part of these rations, which are very similar to the ones Leia nibbles on in Return of the Jedi, and then shares with Wicket, is something like a granola bar.  It appears to be a crunchy stick shaped item, probably composed of nuts and grains.  Luke and Leia don't seem to mind the taste, but they also don't seem to particularly enjoy it either.  Yoda is outright disgusted by them, but Wicket appears to enjoy them quite a bit (although we should bear in mind that Wicket's tribe are more than happy to eat people and Wookiees, and Yoda finds his stew delicious, but Luke almost spits it out in disgust).

Wookieepedia is no help here;  this is how they describe the contents of the food ration kits:

A large, yellow, square-shaped object; a rectangular bar; several bits of small tan pieces; a large stick; several medium-sized sticks; small rolls; small brown pieces; white pieces; orange pieces; tiny sticks; a small, yellow, square-shaped object; and white rolls.

The Meal on Bespin:
In an early draft of the script for The Empire Strikes Back,  in the scene in which Vader surprises Han, Leia, and Chewbacca in Cloud City, everyone actually sits down at the table and eats a meal.  The menu isn't described, but the food and drinks appear to be quite good, although no one (except Lando) is in the mood for fine dining, for obvious reasons.
Foods Eaten by Non-Human Characters:
This is where things get a little bit gross.  Chewbacca is so intrigued by the weird, dead, monkey-like thing impaled on a stick on Endor, so much so that he inadvertently triggers a trap, thereby snaring the entire team in a net, where they are soon discovered by the Ewoks.  So Wookiees eat gross stuff.

Jabba eats the frog-like creatures in the fishbowl by his throne.  Also gross.

Beverages:
We all know that Luke, Owen, and Beru drink blue milk - at least, that's what everyone calls it.  It turns out that this is actually milk from the Bantha, which are native to Tatooine, and the blue color is a natural attribute of Bantha milk.  In the Cantina in Mos Eisley, everyone seems to be drinking the same thing, a strange looking, pink alcoholic beverage of some kind.

This may be the only beverage served at the Cantina, because Luke doesn't ask for anything specific, he just tugs on the bartender's shirt and nods, and the bartender hands him an already-poured glass of the stuff.  The characters also drink water on occasion.
Food and Beverages Mentioned on Wookieepedia:
Wookieepedia has an extensive list of stub articles related to foods and beverages.  Some of the entry titles are strange, but many of them are pretty familiar.  Some of the more recognizable items include things like:

Blackberry Pie
Liver and onions
Various types of beers, ales, and lagers
Brandy
Wine
Wheat
Bananas
Cereal
Milk
Cream
Butter
Dumplings
Canapés (an appetizer, usually consisting of a pastry and a filling, which can be either sweet or savory)
Cakes
Corn
Cloudberries
Cheese
Custards and puddings
Bread
Ice Cream
Sandwiches
And so on.  You can find many more examples on Wookieepedia.

Summary:
It appears that the human characters of the original Star Wars trilogy eat and drink things that are more or less similar to foods and beverages here on earth.  Some of the particulars may be different - for example, the dairy products on Tatooine come from Banthas, not cows - but the similarities seem to outweigh the differences.
The staple crops on earth - wheat, grains, and starches - all have their equivalents in The Galaxy Far, Far Away.  The foods we might consider "pleasure foods" or luxury items also have their equivalents there:  pastries, sweets, fats, etc, like ice cream, cake, candy, and butter.
Comment: Those small white and orange things in Luke's survival rations look like [Tic Tacs](https://en.wikipedia.org/wiki/Tic_Tac)!
Comment: those rations are served in those plastic toolboxes/screw boxes with transparent tops and their segments taken out. Hah!


How much cpu usage is too much

Question: I'm almost done with an app and I noticed that it runs at about 6-12% cpu when its in the background.  Is this too much?  What's a good amount our does it mostly depend on the app?
Answer: It does depend on the application. 6-12% CPU would be too much for a software like text editor. But it would not be too much for a web crawler and indexer crawling and indexing the web through 30 threads.
Whether it is too much or not also depends on the nature of other processes running on the system. While 6-12% CPU usage may not be threatening to other processes running on the system, but in case you are running a CPU intensive task say, sorting gigabytes of data that you need very urgently or indexing the web, you would want the CPU usage to go as high as 80% or even more and as a result you wouldn't want to run any other CPU intensive process on the server.
Answer: If you are concerned that you may be doing some wasteful operation without realizing it, you may want to use the profiler to see if you are spending too much time in code that you shouldn't. It may also be the case that your app requires 6-12% CPU for what it does, which shouldn't a problem if it's actually putting it to good use.

How much cpu usage is too much