Will marking on graduate application that I'd like to be considered for admission without funding hurt my chances of receiving funding?

Question: One of the graduate schools I'm applying to asks if I would like to be considered for admission even if they can't fund me. Would it hurt my chances of receiving funding if I checked "yes?"
Answer: It shouldn't but it might.
For example, in my department, if you are the best candidate then you will get the funding no matter what. However, if you have exactly the same qualifications with another candidate (almost never happens) and we have funding only for one, we would offer the other candidate funding and to you to come without funding. Of course, once at the department, we would try to get funding for you for the next semester/year.
All these, depend on the department policy though.
Answer: That very much depends on the local policy. In any case, if I had funding for, say, 5 students and could take on 10, I'd fund the 5 best (or the 5 best which asked for funding), and got 5 out of the rest. But that's me...


04 Acura RSX power steering

Question: Does anyone know the tool that helps stop the power steering from moving while tightening the nut??
Answer: Put a long screwdriver through one of the holes in the pulley. Brace the blade end of it against the body of the pump. Place it in a way so the pulley won't move. Ensure the end isn't against something which will break (like something plastic). Then tighten the nut. There really isn't (to my knowledge) any real "tool" to get this done. You just have to wing it.
Answer: I've found that a "strap wrench" is useful in cases like this.
Comment: Another thing to try is to, with the drive belt installed, press the belt further to increase the tension and tighten from there. Doesn't always work but it might help in a pinch.

04 Acura RSX power steering


importance sampling rectangular light

Question: I have been struggling very much to wrap my head around this part of Peter Shirley's book. There is no explanation what the angle Alpha represents and to make things worse in the code the cos(Alpha) is calculated is the y component of the direction vector from hit point to a random point on the light source. The whole thing makes no sense and I am struggling to find any resources to help me along.
Comment: It's the factor that pops out when you rewrite the integration over the hemisphere as integration over scene surfaces. See stewart's calculus link here for a proof: https://math.stackexchange.com/questions/608637/proof-of-solid-angle-theorem
It can also be shown using differential forms, it's the factor that arises from projecting an arbitrary differential area on the unit sphere (it's the Jacobian of such a map).
Comment: If $Q$ is the point on the light and $P$ is the center of the hemisphere, then alpha is the angle between $P-Q$ and the normal at $Q$ (the normal at the point on the light), as already noted by Nathan Reed.
Answer: From looking at the equations, it looks to me like alpha must be the angle between the surface normal of the light source, and the ray direction. This is the "projected area" factor: the amount of solid angle subtended at the receiving point has to be scaled based on how much the light source is tilted away from the receiver.
The calculation of cos(alpha) as the y component of the direction vector, I suppose, must be in the coordinate system of the rectangle light, where xz is the plane of the rectangle. In such coordinates, the normal will be (0, 1, 0), and cos(alpha) would reduce to dot(direction, normal) which would be direction.y.

importance sampling rectangular light


Software package recommendation please

Question: I am looking for the best value, basic, beginners software packages that can help me create my own personalised cards & print gifts for friends & family please?
Comment: If you're doing this for personal use, I would look into open source (free) software. Like GIMP for images and inkscape for vector drawing.
Comment: Hi Kirsten. What have you tried already and what you didn't like or did like about those? What apps did you research, between which are you chosing?
Comment: The software you know how to use. Since all the other metrics are opaque to us.
Comment: Use whatever came on your computer. Most systems come with a basic image editor and text editor.
Answer: If you are printing these yourself on a home printer, you may already have software that you could use, such as a word processor, like MS Word. Or painting software such as MS Paint. Sure these are pretty basic, but you could use them to layout a simple print project with text and graphics/photographs. If you don't have or want to buy or use MS Office products, then there's also LibreOffice which is free and open source.
If you want software that's more capable, and you don't mind a bit of a learning curve, then there's some Open Source software (all free) that you might want to have a look at:

GIMP which is a raster image editor for manipulating photographic
images, similar to Adobe Photoshop.

Inkscape is a vector image editor for creating logos and graphics, similar to Adobe Illustrator.

Scribus is desktop publishing software for page layout, similar to Adobe InDesign. This software also supports CMYK colour for commercial print jobs.

Krita - digital art/painting software, raster based, but with vector capabilities too. This software also supports CMYK colour for commercial print jobs.
Answer: If you want to do simple things to be sent in electronic format you can use the free version of canva.com
Designing is not an easy task, and that web page gives you some simple tools to add elements to some already defined templates.
Comment: I do like canva, I have recommended them to friends who needed to make a design with 0 design skills.

Software package recommendation please


How to disable microphone volume auto adjustment in Cisco Webex

Question: I am using Cisco Webex for the online meetings, the problem is that the microphone volume automatically goes to maximum and I just can't decrease it. Is there any way to solve this problem? Any help would be highly appreciated!
Answer: I had a similar problem. Sometimes it is impossible to prevent applications from trying to adjust the microphone level. With Ubuntu, it is at least possible to prevent ALSA from responding to such requests.
In the configuration file /usr/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.conf (you might have to look for the correct file for your microphone, see below), I changed to part
[Element Capture]
switch = mute
volume = merge
override-map.1 = all
override-map.2 = all-left,all-right

to
[Element Capture]
switch = mute
volume = 40
override-map.1 = all
override-map.2 = all-left,all-right

and after a sudo alsa force-reload, applications don't magically change the microphone volume anymore.
Above, we use volume = 40, which corresponds to the numeric value shown in alsamixer below the green level control fader as shown here: .
If you want to set the volume to the "native" volume of your microphone (0dB of the hardware, without added "mic boost" that can add static noise), adjust this volume number until the top left of alsamixer shows db gain: 0.00, like so:

How to determine the .conf file for your microphone

Run pacmd list-sources.

In the output, search for the index: section listing the desired device, e.g.
  * index: 6
    name: <alsa_input.usb-Blue_Microphones_Yeti_Stereo_Microphone_REV8-00.analog-stereo>
    ...
    active port: <analog-input-mic>

The active port part at the end contains the file name you need to edit in /usr/share/pulseaudio/alsa-mixer/paths/.
In the above example, it is <analog-input-mic>, so we would edit /usr/share/pulseaudio/alsa-mixer/paths/analog-input-mic.conf for this mic.
Comment: Doesn't work for me on Ubuntu 20.04
Comment: This _seems_ to work for me for Ubuntu 18.04. I came here via the [Chromium bug](https://bugs.chromium.org/p/chromium/issues/detail?id=435112) closed as `WontFix`, in which Chromium refuses to allow users to disable automatic mic adjustment (in my case, the Mic Boost, not the absolute volume); instead they make it each WebRTC app's ability to disable it, but if any app you use there doesn't offer a setting for it, you're screwed. This workaround seems to help. However, even though I specify `volume = 40` for my mic boost, the value stays at the value I set in alsamixer, not 40. Suspicious.
Comment: I just noticed that I had answered the same question with the same answer [here](https://askubuntu.com/questions/279407/how-to-disable-microphone-from-auto-adjusting-its-input-volume/736655#736655) 3 years ago :o
Comment: Did work for `Linux Mint 19.3`  `5.4.0-48-generic`
Comment: It works, but when i return back to Chrome and Cisco Webex - it says, that i have no mic and auidio at all (it is only webex issue, e.g. in other sites like Youtube sound exist and everything is normal also as in desktop apps like discrod or zoom ). After reset  - all configs are back to default. How to prevent such behaviour - i don't know


Interim secret clearance question

Question: I recently got a summer internship, and I need a secret clearance for this. Apparently it will be interim, for obvious reasons, but I was just wondering if the background check/investigation process was any different for interim clearances than permanent ones.
Answer: I've had both internships and full-time work in the defense industry. I've never heard of anyone only getting an interim clearance. They usually grant an interim after you submit the paperwork and they start the process and decide that the likelihood of problems coming up is low.
The interim clearance exists to let you start receiving your classified training, access the classified facilities, and begin work on the projects while the investigation and paperwork are concluding.
I suppose it's possible, though, but you should prepare for the exact same paperwork and process as anyone else getting your clearance level and consult the security office after you start to learn more. If you're accessing classified material, you will have an exit briefing at the end of your internship where they will explain how long your clearance is valid and what you may need to do should a future employer need to reinstate your clearance.
Comment: @MonicaCellio A previous employer only hired co-ops for 6 month or longer blocks because of the time. Most people had their interim in 2-3 months and there was sufficient unclassified work around the system to ramp up on before it came through. But the duration is a concern, for sure. Although I did interview people for co-op positions who had TS or even TS/SCI from internships, which I thought was odd due to the time and cost.
Comment: This matches my experience in the US.  And I don't think I've heard of an employer that would pay the considerable cost for an intern who'll be gone in a few months, long before final approval comes through.  Even my interim took a couple months, as I recall, though maybe they're faster now.
Comment: I just would like to add a +1 to this.  I have the same exact experience (US).  I got my interim clearance while a longer process (took around two months) to get "permanent" clearance. During the interim period I had training, and started some simple work, then later with the "permanent" clearance I was given my "full" work. Keep in mind, that depending on level, the process is really not much more then waiting, but you should have access to a "Security Officer " (ask HR) that can answer any questions you may have.

Interim secret clearance question


Is there any way to increase a weapon durability?

Question: I want to stick to a particular weapon in Dark Souls 2, but my weapon is breaking too fast between combats, thus making me switch to another weapon quite often. Is there any way to increase my weapon's durability?
Answer: http://darksouls2.wiki.fextralife.com/Bracing+Knuckle+Ring
Decreases the rate durability goes down. To my knowledge...I don't think there's any other way to prolong equipment life.
Comment: The only other thing that I could recommend besides the Bracing Knuckle Ring would be to take a few of that specific weapon around with you, use lower quality ones and then switch to the higher quality when you fight bosses. This works well at least until you get one of the rings.
Answer: If you are playing on PC, then durability is drastically affected by the improved framerate on this platform.
A reddit user has done lots of research into this, but the long and short of it is that a lot of actions in the game are measured in number of frames.  As the PC version runs at 60fps, a number of these actions are doubled up.  This mainly affect durability when you swipe through a fading out enemy (after killing them) but it also affects the animation speed of various attacks.
To mitigate the effects, you can use your graphic's card drivers to limit the framerate in DkS2 to 30fps, with the trade-off that movement isn't as fluid.
Comment: Is this for real? I'm about to burst into manic laughter and tears if this is for real.
Answer: Use the brace knucle ring found in Lost Bastile
Comment: Kickpuncher11 has already given this answer.
Comment: But this does mention that it's found in Lost Bastille, which the other one does not (although the linked article does).


MacBook Air Help Please

Question: I have a MacBook Air and random advertisements and tabs have been popping up, I wanted to know if I take it to my nearest apple store can they figure out a way to help me fix this for free or at least at a low price?
Answer: Oh dear, it sounds like you have adware!
However, you can clean this up yourself very easily for free. There is a tool call AdwareMedic (which you can download from this website); download it from the website, install it, and run it. It'll guide you through the steps, and when you're done, it will restart your computer. Once it turns back on, you should be free from all of those annoying ads. You can then uninstall AdwareMedic, if you would like.
I hope this helps you!

MacBook Air Help Please


How to upgrade my Mac Pro to an OS newer than 10.6.8?

Question: I have a Mac Pro running Snow Leopard. I tried upgrading to Mavericks, but the App Store won't let me download it. It directed me to this page. At first I thought it was because I was out of space (8GB required) so I deleted some things. Now I have 8.17GB available with 5GB of RAM (2GB minimum). The only thing I can think of is that my Mac Pro is arbitrarily too old. However, I don't know how to confirm that. I'm not even sure if there are any upgrade options available. What do I need to do?
Answer: It sounds like your Mac Pro is not supported (too old?) by a newer OS than 10.6.8.
Check by looking in the System Information app, to see what version of Mac Pro it is. Supported versions are "MacPro3,1" or greater. Unsupported versions are MacPro1,1 or MacPro2,1.
The reason why the older models are not supported is not arbitrary - it's because the first models had a 32-bit EFI, and the later ones have a 64-bit EFI. The later operating systems require a 64-bit EFI.
Comment: The MacPro1,1 and 2,1 can be upgraded to 10.7 Lion (you have to [purchase a redemption code to use in the App Store](http://store.apple.com/us/product/D6106Z/A/os-x-lion)). But IMO 10.7 was actually a bit of a downgrade from 10.6; they changed a bunch of stuff, and didn't really get it sorted out until 10.8.
Answer: I have an old Mac Pro myself. It's an Early 2008 (aka a MacPro3,1). Please verify that your Mac meets this criteria or is newer than that.
You can check what model you have click on the Apple icon in the menubar (top-left on you screen) and click "About This Mac" > "More Info".
There select the Hardware tab (I think it's preselect) and check your Model Identifier.  Also see this video tutorial.
You can use MacTracker to search for it and get the new name scheme with 'Model Name (Year)' out of it and compare it with the list of compatible model you linked to.
And, … if your Mac meets the minimum criteria, you could try freeing up some more space (maybe around 500 MB) to be on the save side. Then try again.
Basically if you got a MacPro1,1 (~August 2006) or MacPro2,1 (~April 2007) you're not officially supported and I would advice against trying to upgrade your Mac forcefully since compatibility issues would arise regularly. Anyway, if you still want to check out one of the tutorials you'll find when searching for "upgrade old mac to mavericks".


Masked variables in logistic regression

Question: I have a logistic regression model with variables $V_1$ through $V_n$. When I build a full model with all of the variables, I find that $V_1$ and $V_2$ are significant. However, when I build a new model in which I remove $V_1$, I find that, in addition to $V_2$, $V_3$ is now significant. I assume this occurs because $V_1$ and $V_3$ are correlated, so that all the information $V_3$ is captured in $V_1$ in the full model. $V_3$ is of particular interest to me given my hypothesis, so I'd like to know what it's reasonable to say about $V_3$ in terms of significance. Can I still report that $V_3$ is significant even though it's masked by $V_1$? Are there further tests I can do that would be informative here?
Answer: It is important to have theoretical justification for including variables in a model to avoid "fishing" for significance.  The first thing you should do is try to understand the underlying relationship between $V_1$, $V_3$, and $y$.  Are $V_1$ and $V_3$ similar measures of the same thing, such that including both in the model is redundant, or does $V_1$ confound the relationship between $V_3$ and $y$?
If the former, you could (reasonably) justify dropping one of the covariates from your model, because there is no additional information gained by including both of them in your model as they are measures of the same thing.  If the latter, you absolutely should NOT drop $V_1$, as failure to control for $V_1$ would lead to omitted variable bias, resulting in inconsistent parameter estimate for your main covariate of interest, $V_3$.  Why would failing to control for $V_1$ bias your results in the second scenario?  Suppose the true relationships are as follows:

$Corr(V_1,y)≠0$  (there is a relationship between $V_1$ and $y$)
$Corr(V_1,V_3)≠0$ (there is a relationship between $V_1$ and $V_3$)
$Corr(V_3,y)=0$ (there is NO relationship between $V_3$ and $y$)

If $V_1$ and $V_3$ are correlated and you do not control for $V_1$, the initial observed relationship between $V_3$ and $y$ actually reflects the (true) relationship between $V_1$ and $y$. The parameter estimate on $V_3$ is, in effect, a combination of the effect of $V_3$ on $y$ AND the partial effect of $V_1$ and $y$.  Because in reality there is no relationship between $V_3$ and $y$, once you control for the factor that is "responsible" for the observed relationship (i.e., $V_1$), the coefficient on $V_3$ is no longer significant.
I would report that $V_3$ was significantly associated with $y$ in bivariate analysis, but that the relationship becomes non-significant after controlling for $V_1$ and discuss why you think this is.  You may find it helpful to dig into the literature for insight on the relationship between $V_1$, $V_3$, and $y$.
Comment: Thanks! What's the best test of association between $V_3$ and $y$ that you'd recommend performing here?
Comment: I want to clarify that when I say "true relationship," I mean the relationship at the population level.  Very often, this is not observable to us, as we work only with a sample drawn from that population.  We can't know what the true relationship is just from one study.  This is why it's important to dig into the literature and see what others before you found.  That said, the p-value in your regression model output is a formal test of the association between $V3$ and $y$.  You can do a post-estimation Wald test, but the p-value will be roughly equal to the p-value in the model

Masked variables in logistic regression


Robocopy job will run manually but not as a scheduled task

Question: Using Robocopy on Server 2012.
I have created a .cmd script to copy some files from a mapped drive to the local machine.
The mapped drive is on another server in a different domain and connects with the remote domains domain admin credentials. Domains are not trusted.
It works if i double click the .cmd file and run it manually (logged in as domain admin)
But as soon as it runs as a scheduled task (running also as domain admin) it complete with status code 0 but doesn't actually copy anything.
Simple line from the script:
<code>    @echo on
START /WAIT c:\windows\system32\Robocopy.exe "W:\Folder1\Folder2\Folder3\Folder4" "C:\Folder1\Folder2\Folder3\Folder4" file.txt /np /LOG+:"C:\RCLog\schtask.log"
</code>
When run manually the log file contains:
<code>-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robust File Copy for Windows
-------------------------------------------------------------------------------

  Started : 13 December 2013 10:51:59
   Source : W:\Folder1\Folder2\Folder3\Folder4\
     Dest : C:\Folder1\Folder2\Folder3\Folder4\

    Files : file.txt

  Options : /DCOPY:DA /COPY:DAT /NP /R:1000000 /W:30

------------------------------------------------------------------------------

                       1    W:\Folder1\Folder2\Folder3\Folder4

------------------------------------------------------------------------------

               Total    Copied   Skipped  Mismatch    FAILED    Extras
    Dirs :         1         0         0         0         0         0
   Files :         1         0         1         0         0         0
   Bytes :     4.1 k         0     4.1 k         0         0         0
   Times :   0:00:00   0:00:00                       0:00:00   0:00:00
   Ended : 13 December 2013 10:51:59
</code>
But when run from the scheduled task:
<code>-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robust File Copy for Windows
-------------------------------------------------------------------------------

  Started : 13 December 2013 10:44:47
2013/12/13 10:44:47 ERROR 3 (0x00000003) Getting File System Type of Source W:\Folder1\Folder2\Folder3\Folder4\
The system cannot find the path specified.

   Source - W:\Folder1\Folder2\Folder3\Folder4\
     Dest : C:\Folder1\Folder2\Folder3\Folder4\

    Files : file.txt

  Options : /DCOPY:DA /COPY:DAT /NP /R:1000000 /W:30

------------------------------------------------------------------------------

2013/12/13 10:44:47 ERROR 3 (0x00000003) Accessing Source Directory W:\Folder1\Folder2\Folder3\Folder4\
The system cannot find the path specified.
</code>
Anybody any ideas please?
Thankyou
Answer: Just use the UNC path to the remote server instead of drive letter W:
Probable reason is the network mapping isn't available during the scheduled task.
You can also change your script to map the drive, do robocopy and unmap it in the end, but it's simpler to use UNC path.
Comment: Had this problem, and this was the solution. Thank you.
Answer: When the job is run from scheduler, given credentials are used only for authentication, not for recreating whole user's environment. You must copy directly to UNC path or map S: drive to UNC within the script prior to robocopy command.
Going to your issue, in the script , before the ROBOCOPY command add net use w: \netshare_path$.
If the script will find the letter w used by a mapped drive will error but continue with ROBOCOPY. If the letter w is not used will map the drive to it and use it in the ROBOCOPY. If you don't need the mapped drive just put in the script the net use w: /delete after ROBOCOPY.
So it should look like this:
<code>NET USE W: \\server\drive_letter$ /USER: <USERNAME> <PASSWORD>
ROBOCOPY "W:\Folder1\Folder2\Folder3\Folder4 " "C:\Folder1\Folder2\Folder3\Folder4 " file.txt /np /LOG+:"C:\RCLog\schtask.log"
NET USE W: /delete
</code>
Answer: For Winrobo copy use the UNC path for the remote server.
URL = http://www.upway2late.com/projects/winrobocopy


Alternatives to domain transfer

Question: Last month I changed hosting providers to HostGator and transferred my domain name to them. Since then I've had nothing but headaches dealing with their support, so I set up my own web server at home to host from (it's only a small portfolio site). My home network connection is a dynamic IP address, so I'd like to use No-IP as my registry because of their services specifically for dynamic IPs. I made the mistake of signing up for a 3 year discount deal with HostGator, so I really need to get my money back. But their money-back guarantee only lasts for 45 days, and I'm still subject to the 60 day wait period to transfer my domain name. What can I do in this situation? I need the refund, even if it means leaving my domain open to public purchase for awhile, but I'm hoping there is a way around that.
Answer: This question is not technical but about contracts.
Domain transfer IS the correct alternative. If your domain has any value (economic, reputation, even vanity), you should NEVER let it expire and become available. If the domain has any fame, it will most likely be automatically bought by someone who will claim "ransoms" if you want it back. Compared to that, already paid hosting fees are small and could be regarded as doctrine money.
Usually it is wise to separate hosting from domain registration and hold your domain on a registrar that guarantees the sovereign ownership and full control of your domain name. Luckily, HostGator doesn't seem malicious, since they are providing directions on how to get the authorization key.
Secondly you might benefit having DNS somewhere you can add your own records if you are ever willing to have any services on different providers.
Comment: My domain really doesn't carry much reputation/ranking, nor do I really need it to. But I'm interested on your point about separating registry from hosting. Would you mind expanding on that?
Comment: Many registrars are just providing service on registering domain and most of the hosting companies are not registrars themselves but buying the domain from a registrar for you. Some malicious hosting companies are buying the domain names for themselves as they were only renting it to you. That's an unethical way of holding the customers.

Alternatives to domain transfer


Synonym for character (as in a person in a book)

Question: A story normally consists of several characters (i.e. the protagonist, the antagonist, and so forth), but is there a good synonym for the word character? I've often used "people", but it seems overly general.
Comment: probably - role ?
Comment: It might help if we knew why *character* doesn't work for you.
Answer: You can try 'personage', or 'figure'.
If you were to refer to the cast in general, maybe you could use 'dramatis personae', although that seems a bit grand / presumptuous.
For example, if you were writing a sordid piece of tabloid gossip, then 'dramatis personae' won't lend you a patina of respectability. Instead it looks overdone, like gaudy cheap jewelry. :D
On the other hand, if it was a review of a stage play or a novel, then dramatis personae is acceptable, though a bit heavy and somber (which may or may not be what you want).
Answer: Most of the answers seem to refer to a play, rather than a book. I shall also, but I offer less formal alternatives:

players

major players

minor players

bit players

In addition you might, if appropriate, refer to a cameo appearance.  https://en.m.wikipedia.org/wiki/Cameo_appearance
(by the way, the above work best for fiction; for non-fiction you might prefer figures, as was suggested earlier.)
Comment: +1. I'm reminded of the opening credits from early silent movies.
Comment: I like players, it allows easy distinguishing of their impact on the story also
Answer: I can't think of a close synonym for character in this sense. To refer to all the characters collectively, you can use dramatis personæ

Dramatis personæ (Latin: "persons of the drama") is a phrase used to refer collectively, in the form of a list, to the main characters in a dramatic work. Such lists are commonly employed in various forms of theater, and also on screen. Typically, off-stage characters are not considered part of the dramatis personæ. It is said to have been recorded in English since 1730, and is also evident in international use. However, the term is closely associated with the works of William Shakespeare and appears in the original publication of the First Folio, published in 1623.

It is usually applicable to plays, but can be loosely used for other works.
Example sentences from Vocabulary.com:

The draw of "Scandal" has always been its schizophrenic pacing and the elaborate, interconnected backstories of its dramatis personae.
Perhaps the most fascinating of these dramatis personae is Zukor, nicknamed "Creepy" by his employees for his habit of speaking sparingly and softly.

The second sentence shows how you can use the term for a singular character by paraphrasing a little.
Answer: I understand your hesitation with the terms protagonist, antagonist, character. The terms are Greek, mainly referring to drama and from an older time. Today when we talk about novels such terms look like anachronisms.
I speak of central figure or central person of a novel. The term dramatis personae, Latin, refers only to a theater play and it is an old term as well.
Answer: Although I support the usage of 'figure', I will propose an alternative other than those already suggested.
Although mainly used in plays or scripts, the term 'Actor' can be used in the same context. This can be seen in other usages such as video games where it is sometimes common practice to term all people in the game as 'actors'. I think it is applicable in this usage due to many games being broken into 'scenes' or levels.
I would hesitate to use this terminology in terms of books, but it is could be used in consideration to that parts the (character/figure/etc) has to play in the story. The 'actor' may play a very minor part, or a major part, but they still influence the experience in some way.


Estimate distribution of a composite variable

Question: Suppose I have N sets of numbers (10 numbers per set) {a1, ....., a10}. I form a sum by taking one number at random from each set. SUM = num from set 1 +......+ num from set N. If I do this a large number of times I will generate a large number of different values for the SUM variable. How can I estimate the distribution of the SUM values (P10, P50, P90 etc.)?
Comment: First of all, you haven't defined a distribution, but I'm assuming that you're picking the number uniformly and independently. Second, what do you mean by "estimate the distribution of `Sum`"? What kind of answer are you looking for?
Answer: Use a convolution.
For instance, write the generating function for each set, then multiply the generating functions; this gives you the generating function for the distribution of the sum.
This gives you the exact distribution (which is even better than an approximation!).
Comment: D.W. In order to find the exact distribution of the values of SUM would I not have to evaluate all possible combinations of the summed values/
Comment: @DavidWilkinson, no, you would not.  My answer describes how to do it, *without* evaluating all combinations.  I recommend you read about convolutions and generating functions, if you're not already familiar with the subject, as they solve exactly this problem in an elegant, efficient way.


How do I get rid of these insects that are in all of my planters?

Question: How do I get rid of these insects that are in all of my planters?
I find them only to be in the dirt and not on the plants.
To me they look spider mites, but they did not die out when I applied Bayer Advanced™ 3-In-1 Insect, Disease & Mite Control on them directly, they just scampered on.
I'll add pics once I get home so you can come to your better judgments.
Comment: Are you sure they are damaging your plants? Also, bayer advanced doesn't always kill immediately. The insecticide used in that product is [Imidacloprid](http://en.wikipedia.org/wiki/Imidacloprid), a neurotoxin, so it won't kill on contact like some insecticides. The miticide used is [Tau-Fluvalinate](http://en.wikipedia.org/wiki/Fluvalinate), which is a different neorotoxin affecting sodium channels in mites. Don't expect immediate results.
Comment: Thanks for the info regarding the product im using. I dont want to wait for it to get to that point
Comment: Chances are good that these are fungus gnats.  They do not harm the plant and can be controlled by good cultural practices. See http://gardening.stackexchange.com/questions/3306/indoor-garden-built-now-little-flies/3314#3314
Comment: I tried to get some pics last night but they're too small for  me to focus on. so I'll explain what I see, they basically look like little clear/silvery sesame seeds with no wings.
Answer: I like to give the recommended dose of diluted Neem oil weekly to keep off the insects, it has worked wonders here in Florida. As Kevinsky also commented, it is possible they are fungus nats and wont harm the plants in any way.
Comment: @ Apoc Yes I added neem oil to my next shopping list thanks. As for the fungus gnats although they arent damaging the plants just anoying, they lay lots of eggs in the dirt and when they hatch they feed on the roothair a slow downward spiral for plants.
Comment: BTW do I have to dilute "Bayer Advanced Ready-to-Use Natria Neem Oil"?


Tannaka duality for closed monoidal categories

Question: I asked this some time ago at mathstackexchange, and people there explained to me the mathematical part of what I was asking, but the question about references remains open. In my impression, people here at MO are more active, so I hope, specialists in the category theory could clarify the remaining part of my question. (At the same time I foresee that somebody can suggest another idea of how this can be proved, and I would welcome this as well.)
The nLab article on the Tannaka duality says that this theory was generalized to monoids in arbitrary closed monoidal category (symmetric and complete in some sense):

if we take a monoid $A$ in such a category $\mathcal V$ and consider the category $_A{\mathcal V}$ of all left modules over $A$, then $A$ can be recovered from $_A{\mathcal V}$ as the object of enriched endomorphisms of the forgetful functor $F: {_A{\mathcal V}}\to {\mathcal V}$.

(As far as I understand, this result is called a reconstruction theorem.)
Some details in this construction are however explained at nLab vaguely, in particular,

how is the structure of the enriched category introduced on $_A{\mathcal V}$?

Can anybody give me a link to a text where this result is explained accurately so that I could refer to it with a clear conscience? (Perhaps I am missing something, I do not see where this is written. From what I see, I have the impression that this is folklore, but I have no confidence, and I do not dare to write this in my paper.)
Answer: I think a good reference for your question would be R. Street, Quantum Groups, A Path to Current Algebra, Chapter 16: Tannaka Duality (see here).
Comment: I am reading this. This is strange, why don't they want to formulate this result explicitly, as a theorem?


How does one parse XML files?

Question: Is there a simple method of parsing XML files in C#? If so, what?
Comment: @JeremyThompson One of the reasons why this was a duplicate is the other question has a much better answer. The top answer being a simple "link only" answer is not useful.
Comment: @GeorgeStocker the questions are different enough to co-exist and both have **great** answers, plus the accepted ones are using different technologies. That's why I voted we leave this open, I know this accepted one is link only but it is MSDN and was written at a time before that was unacceptable,  hopefully a side effect of reopening is cheering Jon up a bit, *read his profile*. Anyway cheers.
Comment: you could use this implementation: http://stackoverflow.com/a/34813985/5784646
Comment: Ok, I reopened this. The duplicate was an XML Reader solution where as this is about parsing XML files. The *posssible duplicate* can be seen in the questions [edit] history ps @GeorgeStocker
Answer: It's very simple. I know these are standard methods, but you can create your own library to deal with that much better.
Here are some examples:
XmlDocument xmlDoc= new XmlDocument(); // Create an XML document object
xmlDoc.Load("yourXMLFile.xml"); // Load the XML document from the specified file

// Get elements
XmlNodeList girlAddress = xmlDoc.GetElementsByTagName("gAddress");
XmlNodeList girlAge = xmlDoc.GetElementsByTagName("gAge");
XmlNodeList girlCellPhoneNumber = xmlDoc.GetElementsByTagName("gPhone");

// Display the results
Console.WriteLine("Address: " + girlAddress[0].InnerText);
Console.WriteLine("Age: " + girlAge[0].InnerText);
Console.WriteLine("Phone Number: " + girlCellPhoneNumber[0].InnerText);

Also, there are some other methods to work with. For example, here. And I think there is no one best method to do this; you always need to choose it by yourself, what is most suitable for you.
Comment: +1 for mentioning XmlDocument, which is much more convenient than serialisation interfaces in some cases. If you are after one specific element, you can access child elements with the indexer: xmlDoc["Root"], and these can be chained: xmlDoc["Root"]["Folder"]["Item"] to dig down the hierarchy (although it's sensible to validate that these elements actually exist)
Comment: A programmer with a list of female friends? Shenanigans!
Comment: `InnerText` here gets the value of that node, concatenated with all values of child nodes - right? Seems like an odd thing to want.
Comment: @E.vanPutten not in this day and age. This is not Revenge of the Nerds
Comment: @DonCheadle If you aren't expecting there to *be* any child nodes, then `InnerText` will just return the node value - which is what I (and probably everyone else reading this question) am parsing the XML to find in the first place.
Comment: I think this should be the accepted answer. XmlDocument is just that much more convenient to use for "basic" situations.
Answer: I'd use LINQ to XML if you're in .NET 3.5 or higher.
Comment: I tried using this but was unable to figure out how to get something as simple as the value of the identifier of a certain element in my XML  (or how to get an element by identifier, for that matter). In contrast, using XmlDocument I was able to do that with minimal effort.
Comment: I'm with you Kira.  I have yet to grok LINQ to XML, and considering the overhead of LINQ, I've never made the effort to figure it out.  Doesn't seem intuitive to me.
Answer: Use a good XSD Schema to create a set of classes with xsd.exe and use an XmlSerializer to create a object tree out of your XML and vice versa. If you have few restrictions on your model, you could even try to create a direct mapping between you model classes and the XML with the Xml*Attributes.
There is an introductory article about XML Serialisation on MSDN.
Performance tip: Constructing an XmlSerializer is expensive. Keep a reference to your XmlSerializer instance if you intend to parse/write multiple XML files.
Comment: Good example is the "Purchase Order Example" in the middle of this example from microsoft. http://msdn.microsoft.com/en-us/library/58a18dwa.aspx. You avoid having to create a schema -- your c# class is the schema, adorned with C# attributes.
Comment: See http://www.codeproject.com/KB/cs/xsdtidy.aspx and http://blog.dotnetwiki.org/XsdTidyXSDMappingBeautifier.aspx
Answer: If you're processing a large amount of data (many megabytes) then you want to be using XmlReader to stream parse the XML.
Anything else (XPathNavigator, XElement, XmlDocument and even XmlSerializer if you keep the full generated object graph) will result in high memory usage and also a very slow load time.
Of course, if you need all the data in memory anyway, then you may not have much choice.
Answer: Use XmlTextReader, XmlReader, XmlNodeReader and the System.Xml.XPath namespace. And (XPathNavigator, XPathDocument, XPathExpression, XPathnodeIterator).
Usually XPath makes reading XML easier, which is what you might be looking for.
Comment: FYI, you should not use `new XmlTextReader()` or `new XmlTextWriter()`. They have been deprecated since .NET 2.0. Use `XmlReader.Create()` or `XmlWriter.Create()` instead.
Answer: I have just recently been required to work on an application which involved the parsing of an XML document and I agree with Jon Galloway that the LINQ to XML based approach is, in my opinion, the best. I did however have to dig a little to find usable examples, so without further ado, here are a few!
Any comments welcome as this code works but may not be perfect and I would like to learn more about parsing XML for this project!
public void ParseXML(string filePath)
{
    // create document instance using XML file path
    XDocument doc = XDocument.Load(filePath);

    // get the namespace to that within of the XML (xmlns="...")
    XElement root = doc.Root;
    XNamespace ns = root.GetDefaultNamespace();

    // obtain a list of elements with specific tag
    IEnumerable<XElement> elements = from c in doc.Descendants(ns + "exampleTagName") select c;

    // obtain a single element with specific tag (first instance), useful if only expecting one instance of the tag in the target doc
    XElement element = (from c in doc.Descendants(ns + "exampleTagName" select c).First();

    // obtain an element from within an element, same as from doc
    XElement embeddedElement = (from c in element.Descendants(ns + "exampleEmbeddedTagName" select c).First();

    // obtain an attribute from an element
    XAttribute attribute = element.Attribute("exampleAttributeName");
}

With these functions I was able to parse any element and any attribute from an XML file no problem at all!
Answer: In Addition you can use XPath selector in the following way (easy way to select specific nodes):
XmlDocument doc = new XmlDocument();
doc.Load("test.xml");

var found = doc.DocumentElement.SelectNodes("//book[@title='Barry Poter']"); // select all Book elements in whole dom, with attribute title with value 'Barry Poter'

// Retrieve your data here or change XML here:
foreach (XmlNode book in nodeList)
{
  book.InnerText="The story began as it was...";
}

Console.WriteLine("Display XML:");
doc.Save(Console.Out);

the documentation
Answer: If you're using .NET 2.0, try XmlReader and its subclasses XmlTextReader, and XmlValidatingReader. They provide a fast, lightweight (memory usage, etc.), forward-only way to parse an XML file.
If you need XPath capabilities, try the XPathNavigator. If you need the entire document in memory try XmlDocument.
Answer: I'm not sure whether "best practice for parsing XML" exists. There are numerous technologies suited for different situations. Which way to use depends on the concrete scenario.
You can go with LINQ to XML, XmlReader, XPathNavigator or even regular expressions. If you elaborate your needs, I can try to give some suggestions.
Comment: regex for xml. you monster.
Answer: You can parse the XML using this library System.Xml.Linq. Below is the sample code I used to parse a XML file
public CatSubCatList GenerateCategoryListFromProductFeedXML()
{
    string path = System.Web.HttpContext.Current.Server.MapPath(_xmlFilePath);

    XDocument xDoc = XDocument.Load(path);

    XElement xElement = XElement.Parse(xDoc.ToString());

    List<Category> lstCategory = xElement.Elements("Product").Select(d => new Category
    {
        Code = Convert.ToString(d.Element("CategoryCode").Value),
        CategoryPath = d.Element("CategoryPath").Value,
        Name = GetCateOrSubCategory(d.Element("CategoryPath").Value, 0), // Category
        SubCategoryName = GetCateOrSubCategory(d.Element("CategoryPath").Value, 1) // Sub Category
    }).GroupBy(x => new { x.Code, x.SubCategoryName }).Select(x => x.First()).ToList();

    CatSubCatList catSubCatList = GetFinalCategoryListFromXML(lstCategory);

    return catSubCatList;
}

Answer: You can use ExtendedXmlSerializer to serialize and deserialize.
Instalation
You can install ExtendedXmlSerializer from nuget or run the following command:
Install-Package ExtendedXmlSerializer

Serialization:
ExtendedXmlSerializer serializer = new ExtendedXmlSerializer();
var obj = new Message();
var xml = serializer.Serialize(obj);

Deserialization
var obj2 = serializer.Deserialize<Message>(xml);

Standard XML Serializer in .NET is very limited.

Does not support serialization of class with circular reference or class with interface property,
Does not support Dictionaries,
There is no mechanism for reading the old version of XML,
If you want create custom serializer, your class must inherit from IXmlSerializable. This means that your class will not be a POCO class,
Does not support IoC.

ExtendedXmlSerializer can do this and much more.
ExtendedXmlSerializer support .NET 4.5 or higher and .NET Core. You can integrate it with WebApi and AspCore.
Answer: You can use XmlDocument and for manipulating or retrieve data from attributes you can Linq to XML classes.

How does one parse XML files?


Is there a depth at which a human body, with lungs full of air, will no longer float?

Question: I was watching a special on divers who dove down hundreds of feet without tanks or gear.  The show referred to a depth at which the diver was no longer buoyant and would actually sink, even with lungs full of air.  Is there such a point and if so, why?  What is happening there?
Comment: It astonishes me that this question has so many in-depth answers that are simply wrong. This is a well-known, frequently discussed phenomenon among freedivers. Most humans hit negative buoyancy around 30 feet down. https://www.quora.com/How-deep-would-you-need-to-dive-underwater-to-not-float-anymore
Comment: A video featuring Stig Pryds adds some useful info: https://youtu.be/C8Z7FjpWNnk
Answer: The diver would cease to be buoyant when the their average density matches that of the surrounding water; where density is weight (or mass) divided by volume.  The density of the surrounding water is not going to change much with such depths as water is very hard to compress.  However the diver's density will increase as the air in their lungs compresses; their weight remains the same but the volume displaced by their body reduces and thus the average density increases.
The human body's density is relatively close to that of water; a common figure is 985g/liter, vs 1000 g/liter for fresh water and 1020 g/liter for sea water.  That's only 3.5% less dense than sea water, so if compressing air in their lungs can reduce the overall body volume by 3.5% they will achieve neutral density.
Imagine an 80 Kg adult male (176 pounds).  At 985g/l, they would displace about 81.2 liters.  80 Kg of seawater would displace about 78.4 liters (at 1020g/l).  If the diver's volume could be reduced by 2.8 liters, they would reach equivalent densities.
A typical adult male's lungs hold about 6 liters of air; if their lungs could be compressed by 50%, ie: down to 3 liters of volume, their body volume would drop to 78.2 liters, and they would be slightly denser than sea water.  Air in a balloon would be reduced in volume by 50% at a depth of about 30 feet (each 30 feet of depth increases pressure by about 1 atmosphere) - but of course the ribs and lungs are not a simple balloon and the lungs would not compress that easily but they go much deeper.
Overall, these simple calculations suggest that free divers might approach or exceed neutral buoyancy due to lung compression; at the least, their buoyancy would be significantly reduced.
Complications: body densities vary; they start with  full lungs which reduces their initial density (but there is more than enough pressure to compensate for that); good freedivers have larger lung capacity; any gear worn would have some effect on the calculations unless it was neutral buoyant itself, and fresh water would make neutral buoyancy much easier to achieve.
Nevertheless it's quite  credible that deep freedivers would lose their buoyancy.
Answer: Others have explained the physics. I just want to add that those of us with low body fat can become negatively buoyant at the surface if we breath out and empty our lungs. I can sink down and sit on the bottom of a swimming pool. So it is very possible to dive to a depth where you have negative buoyancy but what depth that will be will depend on the density of your body, or how fat you are (since fat is relatively low density compared to other body materials).
I have also personally talked to a free diver who confirmed that at a relatively shallow depth they become at least neutrally buoyant. This typically happens after they equalize the pressure in their ears, a process which uses some of the air in your lungs (if you use the most common shallow-depth equalization technique). If you have ever dived deep enough for your ears to start hurting from the pressure you've gone deeper than the point where you should have equalized the pressure. I think this depth is somewhere in the range of 15 feet. It's quite easy for even a relatively inexperienced snorkeler to reach this depth.
Comment: Yep. When I was young and fit I sank unless my lungs were completely full. I would do it as a trick: assume a facedown floating posture at the surface and slowly dribble air out until I was seated on the bottom of the pool without any having to swim to stay down. These days, I'm afraid I float rather easily.
Comment: Typically bodybuilders who are cutting on fat become negatively buoyant when exhaling, as a few long distance runners. I do scuba diving and saw a few people negatively buoyant when they exhale when talking with them about buoyancy.
Answer: Realistically? No.
For this to happen, your body's density would need to increase faster than the density of water increases as you descend.  This does happen because the bulk modulus of water is extremely high (about $2.2 \times 10^9\, \mathrm{Pa}$ compared to that of air (about $1.4 \times 10^5\, \mathrm{Pa}$). So ignoring the human body part of the problem, you could definitely compress the air in the lungs to a small enough volume that you're no longer buoyant.  If you make some simple assumptions about how buoyant you are and your lung capacity, the math for figuring out the pressure (and therefor depth) needed should be simple.
The main problem is that compressing the air in your lungs is that your rib cage isn't a balloon that can expand or contract.  There is definitely some minimum volume your rib cage can be compressed to before it collapses catastrophically.
The other problem I see is that compressing the air in your lungs will increase the temperature of the air quite a bit.  Even if your ribs could expand and contract like a balloon you'd have to descend somewhat slowly to keep the temperature of the air in your lungs relatively constant.
Comment: This answer is demonstrably wrong.
Comment: Just a note from a study performed in 1943 [1]: 20 human males had a reduced vital capacity in water up to their nipples.  They had about 94% capacity on average compared to when they were standing at on land.  And their lungs were not even at 1 meter below the surface.

[1] https://journals.physiology.org/doi/abs/10.1152/ajplegacy.19184.108.40.206?journalCode=ajplegacy
Comment: And yet, I fill my lungs with air at the surface where I have positive buoyancy, and if I go deep enough I become neutral, and then negatively buoyant.  The _actual_ problem here is that armchair physics can only get us so far; the real test is empirical evidence.  This is why we conduct experiments in physics classes.  (And this isn't a jab at your answer, it's just a cold, hard fact of the reality we find ourselves in as fallible humans.)
Answer: The divers sink because the lungs aren't full of air. The air compresses, so the volume in the lungs decreases. At 90 meters the lungs lose 90% of their gaseous volume. Since the rest of the body is slightly denser than seawater the body sinks. Keep in mind that the body only barely sinks in salt water, so divers often use weights to sink faster.
Air is only 0.027g/cm^3 at 200m depth (which is extremely deep for free divers). Thus it retains more than 95% of it's buoyancy per unit volume.
At much greater depths the ideal gas law over-estimates the density of air; the deepest trenches are around 10000m and air is only half as dense as predicted. Swim bladders use counter current multiplication to pump gas against strong pressure gradients, but they are limited to 200 atm. At higher pressures fish rely on low density bodies which also save energy in these stygian wastelands. These "jello" tissues make the fish too slow and fragile for life near the surface.
Comment: @DanielVestøl: Fixed.
Comment: This is wrong because it assumes the body is made out of water + air. In reality, the body without air is denser than water, but combined with the air in the lungs the density is lower than water.
This is why you don't need anywhere close to 100% compression to become negatively buoyant.


Overlay orthophoto with DTM

Question: I am having a .dxf DSM and a georeferenced .tiff orthphoto. I would now like to simply overlay the orthophoto onto the terrain for visualization purposes. The DSM contains buildings, whose triangles should be colored differently. It works with texture overlays in AutoCAD 3D, however the performance is way too weak. Does anybody now an easier and quicker solution to do so?
Answer: You can use cloud platform Melown.com, you upload DSM and .tiff and you can visualise it. See here an example here: https://www.melown.com/console/link/VEtUb18bSfjxmDNkFC37?mapLoadMode=fit
I am affilated with Melown Tech.

Overlay orthophoto with DTM


Clojure on Android

Question: Is it possible to program Android apps in Clojure?
Can anybody suggest a good tutorial or book, if it is possible?
Answer: Yes, here is main project I am aware of: https://github.com/remvee/clojurehelloandroid
And here is a little tutorial http://riddell.us/ClojureAndAndroidWithEmacsOnUbuntu.html though I would not be surprised if this tutorial is outdated, as it was over a year ago when I played with the code following this tutorial, and remvee's code has since been updated.
EDIT: see the update here from Stuart Sierra and the Clojure/core group: http://groups.google.com/group/clojure/browse_thread/thread/876c90d3ae353c61

"Clojure 1.2.0 works "out of the box"
  on Android, but startup time is still
  a problem. Some members of
  Clojure/core have experimented with
  ways to make this better, mostly by
  selectively removing stuff that isn't
  needed at runtime.
Follow
  http://dev.clojure.org/display/design/Android+Support
  for news. The last update was by Aaron
  Bedra, a Clojure/core member, in
  December 2010. I wouldn't say it's a
  high priority right now, but neither
  have people lost interest.
I personally would not recommend
  writing an Android app in Clojure if
  you intend to release it right away.
  But if you're interested experimenting
  with Clojure on Android and making it
  better, then go for it."
Answer: Clojure benefits greatly from the android 2.2 JIT compiler which greatly improves class load times. Clojure creates lots of small classes which was taking 'forever' to load on previous android versions.
check out this 'in progress' work on a swank plugin for androiding with clojure
Comment: heh, I thought 'swank' here was just another adjective.
Comment: I see, I will attempt to find where this moved to. Pretty cool 404 though :)
Answer: A new option for Clojure on android is ClojureScript.
ClojureScript compiles Clojure into JavaScript which you can then wrap in
an app. This bypasses the Dalvik-VM entirely and avoids the load time issues,
if your app is suited to javascript. many apps looking for more tight
integration with the platform can't use this approach. If your app
can live with out tight platform integration this could save you a lot of
time.
Comment: it's too bad you can't script the java with clojurescript
Answer: I know this is a bit old, but just in case someone stumbles on this, clojure on Android has come a long way since the answers above. The lein-droid and the Neko projects do make it a lot easier to write full android programs using clojure from begining to end.
Answer: This has been answered before. Yes, it is possible with a few minor hacks. However last time I tried it was extremely slow and very memory hungry. This was with Clojure 1.1 and Android 2.1. Things might have been improved since then.
Comment: it does seem that everytime this question gets asked it gets better answers :) (as in the answer is closer to "yes it works" and farther from "it may work someday") perhaps next time it's asked we will get a really 'good' answer
Answer: Search for "Clojure REPL", "Clojure" or "Sattvik Software" in Android Market and you will find
an excellent REPL. I've been using it in my XOOM 1 Tablet, first with Android 3 and now with Android 4.0 without any problem.
If you search hard enough you will find programs for Java (Java IDE), Ruby (Ruboto IRB), Python, Lua, Perl, Javascript (SL4J for the last four, also SigmaScript for Lua), ISLisp (tiny-ISLispdroid), OCaml (OCaml Toplevel), Scheme, C, C++, C#, Pascal, Basic and even Forth!
I regret they still don't have one for Scala!
Comment: This question was not as much as "How can I run Clojure code on an Android device" but rather "how can I write android apps in Clojure"

Clojure on Android


User preferences for icon placement

Question: Is there any study about user preferences icon placement?
Do users expect it to be on the left/right side of the top bar?
Answer: Reading Gravity and Strong Fallow Areas
There's a technical reason for putting icons, avatars, and other secondary UI element in the top right of the screen, at least for websites in a left-to-right languages.
See my answer to this question - What is the best location to place an identity context control (avatar, name, sign out button)
The way that we read and scan pages makes certain areas better or worse locations for primary and secondary UI elements.
Answer: Personally I believe this style of menu prefers the icon on the right, so it doesn't just look like a long empty bar.
If the bar was shorter though I'd probably put it on the left hand side of the text.
Comment: Yeah I'd move it over the right then and leave it there. I'd be really annoyed as a user if a popout kept coming up while I was trying to click something else, especially if I ended up getting logged out or redirected to a user preferences page.
Comment: The bar has actions, it would not be a long empty bar.
We are discussing the icon on the right or on the left side of the logo.
I'm concerned about the expectations when it is on the left because I rely on the logo to go to the home page. Would users expect to go to the home page if they click on the icon?
Comment: Will the icon link somewhere? If thats the case I'd definitely position away from the logo. - Also, how many action are we talking about? Will it fill up the entire bar?
Comment: No, it will trigger a pop over with 'log out' and 'user preferences' options.

User preferences for icon placement


Why are stable fundamental particles fermions?

Question: Within the Standard Model, any particle decay eventually terminates at the same stable fundamental particles, i.e. u- and d-quarks, the electron and neutrinos (let's forget about neutrino oscillations for now), or the respective antiparticles. Those are fermions. Is there a (simple) answer why? Could one, in principle, make a consistent model where the stable fundamental particles are bosons?
Comment: Is the photon not a stable decay product?
Comment: Everything is stable, unless there are lighter particles it can decay to. Boson number is not conserved, therefore a single one can decay. However, the photon is the lightest of them all, so that would be stable. The lightest single fermions cannot decay, however. So perhaps the question should rather be: "Why is there only one stable boson but multiple stable fermions (proton, electron)?" – And I would not call the up and down quarks stable, there are no asymptotically free states with them, they are always bound.
Comment: @MartinUeding "there is only one stable boson" seems not to be quite precise. Photons are a class of particles with different energy content and THE photon doesn't exist. Isn't this a little bit a weakness of teaching the standard model and not explaining that the fermions all unique and indistinguishable (all protons are the same) but photons are not all the same?
Comment: @HolgerFiedler: All particles can exist in different states of energy, so your comment doesn't make much sense.
Comment: @BenCrowell Under equal conditions (altitude to a gravitational source, velocity in relation to another particle) particles are the same; a proton is still a proton, the energy content is due to kinetic or potential energy. Not so the photons. Their energy content is independent from altitude and they all are moving with c. So the question is, how they differ to obey different energy content. I think that electric and magnetic fields as well as photons are composed of more elementary particles. Read my tracts, the conclusions are interesting.
Comment: @Ben In particular, the crutch virtual photons can be elegantly modelled differently for the discrete interactions between electrons and nucleus.
Comment: Related: https://physics.stackexchange.com/q/749614/226902
Answer: The standard model evolved to fit measurements and observations. The observations  have an axiomatic position in any model designed to fit the observations.
Mathematics allows to pick different sets of axioms, making theorems into axioms and former axioms provable as theorems. In a similar way the postulates which tie a subset of mathematical relations to describe the measurements can be changed, and new , mathematically simpler postulates replace them, but the observational ones are still there to be proven from the postulates. In other words in a physics model there are always statements that are axiomatic, connected with observations. A final un-peeling of the onion , asking "why", will at the end hit a "because that is what is observed".
So the "why are fundamental particles fermions" hits on baryon number conservation as a validated hypothesis, and the observation that the proton has spin 1/2 as well as the electron has spin 1/2, and both are stable.
From these three observations/measurements  and conservation laws, the complexity of particle interactions, starting from scatterings of protons, electrons and photons, have disclosed the number of fundamental  particles in the table:

Conservation laws, also basic and axiomatic from observations, of momentum, energy, and angular momentum have led to this table , so that a mathematically consistent model, the standard model could fit and thus encapsulate the plethora of data.
Thus it is the two everyday stable particles of protons and electrons that are underlying the spin determinations of all the elementary particles in the table using consrvation laws. It so happens that it is only the photon that is a stable boson, but the "happens" is a physical observation.
In other words, thinkers did not sit and think " let us assume that most stable particles are fermions and see if this fits the data, if there exists a stable world". The mathematical model evolved to fit the data.

Could one, in principle, make a consistent model where the stable fundamental particles are bosons?

If you are asking about the world we live in, the answer is no: because the stability of matter as we know it depends a lot on the Pauli exclusion principle, also an observational postulate.
Comment: Thanks for your comment. Still, dare to express a slight discomfort with it: it is quite natural that a consecutive chain of asking 'why ist that?' questions about our physical models sooner or later ends with '... because we made the model to meet our observations'. I would like to make one step backwards and understand, why only (if so) the assumption of a  fermionic elementary particle collection  (leaving the gauge bosons aside) makes sense within our QFT framework, or equivalently, which problems would arise elsewise.
Comment: without the Pauli exclusion there are no atoms as we know them and thus no chemistry. Every negative charge around a positive charge would decay down to the ground level because there would be no limit to how many would be in the ground level, so all would.
Answer:
Within the Standard Model, any particle decay eventually terminates at the same stable fundamental particles, i.e. u- and d-quarks, the electron and neutrinos.

Not true - decay chains can also end in stable photons, and at temperatures high enough to create quark-gluon plasmas, they can also end in quarks or gluons.  In general, particles decay into lighter particles whose total decay products have the same total conserved quantum numbers of color charge, weak isospin, electric charge, weak hypercharge, baryon number, electron number, muon number, and tau number.  (Neutrino oscillations allow interactions that violate electron, muon, and tau number individually, but preserve their total "lepton number.")
Answer: Think it by the way that the stability of the properties of the subatomic particles in our surrounding allows us to find the same conditions around for life. A knife would be a knife in Africa as well as in Australia as well as in the Space station.
There are some moments which are important:

If the energy exchange between the subatomic particles would be binary - means it would only exist photons of one energy content - the electrons in atoms would be only in two states, excited or not, and this would be a very poor world. So the bosons are a class of very important particles.
Photons have both oscillating electric and magnetic dipole moments. But only two photons - of the same energy - can have a symbiotic state (photon bunching), bigger clusters (connected through their magnetic and electric dipole moments) are not possible.
The above mentiond stability of our surrounding is a local property only. Near conglomeration of matter, much larger in relation to our sun, the gravitational potential transforms the accustomed world. Electrons or protons no more exist, only neutrons. Under higher gravitational potential neutrons no more exist, only gluon-quark plasma. In Black holes - to be speculative - perhaps even the photons are smelted in constituents.

What the science has done is the classification of the founded elementary particles into the Standard model and the division of this particles into matter constituents and exchange (of energy) constituents.
Comment: "A knife would be a knife in Africa as well as in Australia as well as in the Space station." What di you mean?


Resigning with immediate effect instead of giving notice

Question: I resigned with immediate effect whereas i have two weeks notice.
I was suppose to notify the company two weeks in advance about my notice, and I mistakenly sent resignation with immediate effect.
What can I do to get the salary?
Comment: `What can i do to get the salary for the time I did / will not work?` - That's not a very good question. Why'd you expect you should get the salary?
Comment: Where are you located? Laws about at-will employment differ across geographies.
Comment: I'm confused... did you actually work the 2 weeks? Are you still at the company now, or have you already left? Based on the question, I'm not sure if you left immediately and want to get paid for time you didn't work, you just handed in your resignation and want to work the 2 weeks, or you actually worked the 2 weeks and they're now refusing to pay you for it.
Comment: Also keep in mind that, even if you *did* provide 2 weeks notice, they're not necessarily under any obligation to have you actually work the full 2 weeks (at least in some jurisdictions)... the main reason I say that is that that actually happened to me once where I handed in a 2 weeks notice and they ended up letting me go before the notice period was up. Since I was an at-will employee, they were under no obligation to have me serve the full 2 weeks, so it was perfectly legal for them to do that.
Comment: An accurate answer would require that you tell us where in the world you are, and if you have an employment contract which describes your obligations around any notice periods. In some parts of the world it's entirely possible that you owe them some money (as least technically) for not working out an agreed notice period.
Answer:
What can I do to get the salary?

If you actually resigned without providing notice, you are not entitled to two weeks of free pay.
If you actually want to work the notice period (2 weeks), call the company (your manager) and tell them of the mistake in regards to the notice date.  Maybe they will let you work the two weeks and earn the salary.  In most countries they are not obligated to do so.
Answer: Please don't walk off your job if you can possibly avoid it. Even if you are an entry-level food service worker, it takes time to find another person and make them familiar with the job.  Supervisors, like you, are workers. And when you walk away you make more work for them.
When you walk away that's all they will remember about you. It ruins any good reputation you may have built in that workplace.
And, as you have discovered, you don't get paid for the time which would have been your notice period.
Call your employer immediately, tell them you made a mistake resigning immediately, and ask if you can serve out your notice period.  But don't be surprised if they don't agree; they're probably irritated with you.
Answer: You don't make it clear in the orignal question what timescales are at play here so assuming you've only just done this (and haven't actually left yet) then you could try explaining to them that you made a mistake and you intended to give the two-weeks notice. If they accept that as an error and allow you to retract the "immediate" resignation you can then give two weeks notice and work them, then you can expect to be paid for them.
Typically there's no obligation on an employer to allow an employee to retract a resignation - but this isn't a hard and fast rule. In the UK and Australia for example there's supporting case law for the notion that an employer should accept retractions where a resignation was given "in the heat of the moment" and promptly retracted e.g. where the employee was having a heated argument with their boss and stormed off with a shout of "I quit!" but even those scenarios aren't black and white and rely on there being some evidence of "special circumstances". (see here for some examples and more info)
Assuming they accept your resignation as it stands (i.e. "with immediate effect") then you won't work those two weeks and won't get paid for them.
If you've already actually left, the "heat of the moment" get out might still be enough to get the resignation retracted (assuming you are in a jurisdiction that supports such things) but I'd only be contemplating that if you were to actually planning to stay as resigning again immediately is only going to remove any argument you had that the first should be retracted. So if you have already left and don't wish to return for longer than your two weeks then I think you can safely say that notice period (and it's associated pay) are gone.
The outlook in the states is similar - they are under no obligation to allow you to rescind your resignation without some extenuating circumstances (such as refusing to rescind being classed as retaliation), and typically that would mean actually rescinding it (i.e. staying). If you just want to work out your notice you're only choice is to ask nicely and hope they agree.
Answer: The company has the choice of accepting your immediate resignation or not. If they accept it, they should tell you, you stop working, they stop paying. If they don't accept it, you continue working and getting paid. Best to talk to them in person, state what you want, and see what the company says. But they have the right to just accept your immediate resignation.
Answer: Contact your manager/HR department immediately.
You may be able to retract your notice or extend it, depending entirely on local laws, customs and your manger/HR.
Depending on the wording of your resignation you may be able to claim that it was a simple typo.
Unless you actually work the 2 weeks notice, I am unaware of any laws or business customs where you will be able to claim the pay.
You might also be liable to pay back any vacation days taken in excess of what you have accrued and working the 2 weeks notice might help to cover those days.


Does a work permit come under D Visa (Post Approval) for Germany?

Question: I want to make an appointment at theGerman Consulate, New Delhi for a work permit. I can't get an appointment before April 25. But when I check with the German Consulate in Banglore, I can see that they have an earlier appointment date for D visa (post approval). I can't find the work permit visa option in the dropdown menu. So are work permit and D visa (post approval) the same? Can I book an appointment under the D Visa (post approval) category?
Answer: First of all you have no need to book an appointment for D visa (Post Approval) to submit your passport for stamping. You can walk-in to your nearest Germany VFS center and submit your passport along with your visa approval email (Please mention travel date on email printout) and travel health insurance with minimum validity of 1 month from your travel date.


What is the most common method to find a group for a Flashpoint?

Question: So I just got my first empire Flashpoint, a 2 player job. Since it starts from the fleet, I don't really want to just ask in fleet general chat if anyone wants to do the quest with me. Is there a better way to find groups for Flashpoints? Such as a built in system that I am missing?
Answer: In my experience, being in the fleet and going "/1 [my class] LFG [name of flashpoint]" works reasonably well.
Alternately, paying attention to General and responding when someone goes "[flashpoint] group LF[number]M" for much the same reason.
EDIT: Update 1.3 introduced the Group Finder Queue, and gives out bonus commendations once a day for using it. Learn it. Use it. The more people who use it well, the better it works.
Answer: Gather in the flashpoint location and flag yourself in /who or in the Social window (Press "O") as LFG, you can also leave a short note there (E.g., "LFG Hammer" or just "hammer"). You can then search for people with LFG tags. It's nice tool, but it's a shame not many people use it.
Comment: not very useful **yet**, as I'm sure most people are unaware of it's existence. only way to change that is get the word out :P
Comment: Since not many people use it, it's not very useful.
Comment: For what it's worth I did see an explanation of how to do this in a load screen "tip" a few days ago. If enough people read those maybe it'll become more commonly used.
Comment: Just to provide a current perspective over a year later -- virtually no one uses this still, unfortunately.
Answer: Most people post in general, so I would just do it.  It's effective.
Sometimes you'll also find people waiting outside the start area for the quest, and you can invite them or vice-versa.  It's particularly unambiguous if you or they have the purple LFG icon hovering above you by setting your status in the /who list, as Krazer notes.  I've noticed that most people don't use the LFG flag, unfortunately..
See Andrzej's answer for a description of the new Group Finder tool, which is another option.
Answer: With the recent addition of patch 1.3, the Group Finder is by far the easiest/most effective way to get groups together for flashpoints (both heroic and normal), story-mode Operations, and heroic quests on planets.
It's available from level 10 onwards as a tab next to the minimap.  See the linked official guide for full details.
Comment: I suppose it depends on the relative class balances queuing (and server pop), of course.  You only have to wait if your class is overrepresented - otherwise, the queue will pop instantly if the other people are already there.  On my tank, it's popped instantly every time :)
Comment: It is. My tank character tends to get into queues much quicker than my DPS alt.
Comment: Still, it's worth adding that this doesn't *preclude* you from asking in General chat or forming up your own group manually while queued in the background.  If the queue does pop in this situation it's a bonus.
Answer: Posting in channels can be an effective way of finding groups (though not as ideal as an automatic queueing system or a commonly used /who system). Other games that do have these more effective systems still manage groups with this method.
That said, a piece of advice: If you are partied with no one else, but are willing to start a party, post with "LFM" instead of "LFG". People will be more likely to send you a tell if they too are looking.


inverse Laplace transform by integral

Question: I've seen this formula for the inverse Laplace transform in several books: $$f(t)=\mathcal{L}^{-1}\{F\}(t)=\frac{1}{2\pi i}\lim_{T\to\infty}\int_{\alpha -iT}^{\alpha +iT}e^{st}F(s)ds$$ where $f$ is the original function, $F$ is its Laplace transform, $\alpha\geq 0$ is bigger than the real part of every singularity of $F$, and $t>0$ is fixed. I'm trying to write this contour integral out as an ordinary integral but it's not working. Here is a simple example of my problem with $f(t)=e^{-t}$ and $F(s)=\int_0^{\infty}e^{-st}e^{-t}dt=\frac{1}{1+s}$. Since the singularities of $F$ are in the left half-plane we can take $\alpha=0$. Now the formula for the inverse Laplace transform becomes $$f(t)=\mathcal{L}^{-1}\{F\}(t)=\frac{1}{2\pi i}\lim_{T\to\infty}\int_{-iT}^{iT}e^{st}F(s)ds=\frac{1}{2\pi i}\lim_{T\to\infty}\int_{-T}^{T}e^{ist}F(is)ds.$$ Substituting in $f$ and $F$ and computing the integral in Mathematica gives $$e^{-t}=\frac{1}{2\pi i}\lim_{T\to\infty}\int_{-T}^{T}e^{ist}\frac{1}{1+is}ds=-ie^{-t}.$$ What went wrong?
Answer: When you changed $\frac{1}{2\pi i}\lim_{T\to\infty}\int_{-iT}^{iT}e^{st}F(s)ds$ to $\frac{1}{2\pi i}\lim_{T\to\infty}\int_{-T}^{T}e^{iut}F(iu)du$ (I've replaced $s$ with $u$ is the second part to make this clear) you did the substitution $s= iu$, but you did not do $ds=i\cdot du$, which is why you get $-ie^{-t}$. Multiplying the limit by $i$ obtains the correct answer of $e^{-t}$.

inverse Laplace transform by integral


Measuring capacitance of Metal-Insulator-Semiconductor (MIS) structure with LCR meter

Question: I can not get my head around what a LCR meter measures. My LCR meter measures my device (MIS) which is displayed as C_p and G_p (other components can be neglected). My LCR meter displays C_p, G_p, the applied voltage and frequency. I guess the capacitance of my MIS structure is C_p, but I do not understand why it also displays G_p, why should this be relevant to me if I only want to measure the capacitance?
Comment: Did you tell the LCR meter to ignore conductance? I would expect that this value will be very small if you have a good insulator.
Answer: It's measuring a complex impedance at one or more frequencies and interpreting the measurement as those lumped components. The result is always two numbers at a single frequency, so it should display both (Capacitance and conductance in this case).
If a single-frequency impedance measurement is interpreted as a different circuit, for example parallel RC, the numbers will both change.
The value also gives you an idea of the reliability of the measurement. If the conductance component of the impedance is very small compared to the susceptance of the capacitance then the latter will be more reliable than the former because small phase angle differences will greatly affect the former.
Comment: No, it depends on the measurement frequency so you have consider the impedance or susceptance of the capacitor at that frequency relative  to the resistance or conductance. You would typically pick a measuring frequency appropriate for the situation.
Comment: To clarify your last sentence, you mean if C_p << G_p than this is a hin for a reliable measurement?


How would an interpretivist justify using game theory?

Question: It is often said that interpretivist theory does not, in principle, reject quantitative methods. That said, how could an interpretivist defend using a quantitative method (e.g., statistical model; game theory) as part of their research if they admit that conceptualizing human behavior by way of deductive models and categorical correlations is to fundamentally misunderstand the nature of human subjects? And, why would an interpretivist choose to employ a quantitative method if they admit that the objects of their investigation and the tools by which their investigation is carried out share the same social context?
Answer: Insisting upon a human interpretation to put a result in context does not reduce the value of the result itself.  Interpretations of statistics are still interpretations, after all.  The objection is to considering the result as a meaningful object on its own, outside a context that integrates all of the social constructions that might have pushed the results in one direction or another.  The supposedly objective method is not irrelevant, it is just no more relevant than other sources of ideas.  All sources can be integrated into an overall explanation.
Clinical psychologists of a basically interpretivist bent often use scored instruments, especially projective media, to derive a starting point for searching out ideas about their clients that might be hidden by the client during communication.  They just do not accept that the instrument necessarily 'says' something definite.  After all, the fact that someone gives answers similar to those given by people with a given way of interpreting the world can mean you are one of those people.  But it can also mean that you have been trained or influenced to consider those kinds of answers more acceptable, or that you have an unusual way of taking the world it that produces the same patterns for some other reason.
Various kinds of ascetics, for instance can come across as depressive if you look at how many hours a night one sleeps, what one's food intake is, how one moves through space, and other objective measures, and even opinions about the world and other people.  An instrument will score them that way.  But you can just look at them and see that a different frame of reference is in order.  That does not mean that an objective measure might never tell you someone is depressed when they pretend otherwise in public because they have been trained to not get others down.  It means that you have to actually think, despite the fact you have a supposedly objective instrument.
Answer: I'd say if it's used with judgement; governments after all uses censuses to plan schooling provision, for example - which seems sensible; whereas using statistical means to judge the value of scientific theories, or literature seems wrong-headed to me; though there maybe other ways in which this may be useful  - for example trawling through law records, or gathering economic data.
Game theory, is used in economics, and it seems a useful explanatory schema in perhaps throwing some light on economics; but one can only judge this, if one already knows a something about economics.
Comment: While game theory is most prominent in economics, it is a theory of descision making and therefore in principle applicable/useful in all humanities.


Adding a C wire to an Intertherm system

Question: I am trying to add an Ecobee smart thermostat to an older Intertherm furnace and A/C. I have extra wires running to my thermostat, but can't figure out what to connect to in the furnace wiring. Any help would be greatly appreciated.
Answer: Use the existing black wire
From the wiring diagram for your unit, and the way your A/C appears to be wired, the light grey wire your unit provides for thermostat connection is the C wire.  This, in turn, is connected to the black wire in your thermostat cable.  So, simply use the black wire coming out of the wall at your thermostat as your C wire, and enjoy!

Adding a C wire to an Intertherm system


Intuitive explanation why rate of energy transfer depends on difference in energy between two materials?

Question: The temperature of an object will decrease faster if the difference in temperature between the object and it's surroundings is greater.
What is the intuitive explanation for this?
Comment: I found a duplicate of the question: https://physics.stackexchange.com/q/484663/249968 though the answer there just states the newton's law of cooling without explaining it. So I think it would be better if this question remains open.
Comment: @JohanLiebert thanks for the comment. I understand the equations, but yes, I was looking for a more intuitive approach rather than the mathematical approach
Answer: I think it'll be helpful to think in terms of the kinetics of the constituent particles. When an object is at a higher temperature, the kinetic energy of its constituents is higher. They are more in motion when compared to the ones with a lower temperature.
Now if there's a high temperature object in contact with a lower temperature one, there will be transfer of kinetic energy at the interface. Energy will be transferred in both directions except that the net transfer will be from higher to lower. This is because there are more ways for energy to be transferred from the higher to the lower. But as the temperature difference decreases, the rate of transfer from high to low and low to high are closing in. Until they reach equilibrium where the transfer of energy from either sides are now equal. Thus there will be no more net heat transfer on the average.
Answer: You know that temperature is related to the microscopic kinetic energy of the atoms and molecules that make up a material. For simplicity, let's assume the two materials consist of monatomic ideal gases with one having a higher temperature than the other. Then the temperature of the two gases is a measure of the average kinetic energy of the gas atoms, which in turn depends on the speed of the atoms.
If the two gases are brought into contact with one another, at the interface collisions between the higher speed atoms of the higher temperature gas with the lower speed atoms of the lower temperature gas will transfer kinetic energy to the lower speed atoms. Those atoms will, in turn, move into the bulk of the gas and collide with others increasing their speed. Eventually when thermal equilibrium is reached the two gases reach some common intermediate temperature.
How quickly the temperature rises in the lower temperature gas will depend on how quickly the atoms at the interface move into the bulk of the gas and collide with other atoms raising the overall kinetic energy. All other things being equal, that penetration will be quicker the higher the speed of the atoms after colliding with the more energetic atoms of the higher temperature gas at the interface. That speed will greater the higher the speeds of the high temperature gas atoms, which in turn increases with the temperature of the gas.
Bottom line:  The greater the temperature difference, the more quickly energy is transferred into the interior of the lower temperature material and the faster its temperature rise. For more discussion of temperature I suggest you look at the Hyperphysics website.
Hope this helps.
Answer: Temperature is (to simplify it a bit), the average energy of the molecules, and the more energy each molecule has, the more it can transfer when it contacts molecules in the other object. So each object gives heat to the other proportional to temperature. The net heat transfer is the difference between how much energy the hot object is giving the cold one, versus how much the cold one is giving the hot one, which is proportional to the difference in temperature.
Imagine two friends who each day give 10% of their total money to the other. Since 10% of the richer friend's money will be a larger amount in absolute terms than 10% of the poorer's friend, the net change in the poorer friend's money will be positive, and it will be proportional to the difference in their money. If R is the richer friend's money, and P is the poorer's, then the poorer friend will lose 0.1P but gain 0.1R, for a total change of 0.1R-0.1P. We can factor out the 0.1 and get 0.1(R-P).
This applies to conduction. For radiation, heat transfer is proportional to the fourth power of temperature, so net transfer is given by the difference in the fourth power of their temperatures.
Answer: An intuitive way to think about heat is as a rink of drunken roller skaters wearing perfectly elastic sumo suits.  They are skating around in random directions, with the one caveat that they always skate in a straight line until they bump into something, at which point they bounce like billiard balls.  The skaters have a random distribution of speeds, but the average speed is the "temperature" of the material.
If you have group A with a leisurely "temperature" of 5 mph (barely above walking speed) which comes in contact with group B whose "temp" is 6 mph, it will, at first, be difficult to even tell the temperature difference with just a visual inspection of the groups.  After all, they are all going close to the same speed to begin with.  However, the sumo skaters with the higher speed from group B will eventually start bouncing into skaters from group A, transferring some of their higher energy.  But because the delta is small, it will take a long time for average velocities to change much.
Now, imagine group C with a temp of 20 mph.  These skaters are hopped up on meth and are skating as hard as they can.  When they collide with group A, they will quickly deliver a big jolt of energy to the lethargic skaters.  In much less time, the extra energy from group C will get distributed to the slower members of group A, bringing up their average speeds.  More importantly, each collision between a fast skater and a slow one will produce a much larger average change in both their speeds, and this molecular transfer of momentum is what defines "heat flow".


Transfering shapefiles from ArcMap to ArcPad makes all form fields required

Question: I've figured out how to create shapefiles in the field and record data.  Sometimes I merge these shapefiles in ArcMap and then transfer them to the GPS device in ArcPad using Get Data for ArcPad.  When I do this, every single field in the data collection screen is now Required, which is just unworkable.  Things like FID, Shape, Latitude, Longitude, y_proj, x_proj, and time (from my most recent example) were carried over from merging shapefiles created on different devices and are now all Required despite being fields created and filled by the devices not the users.  I can delete unwanted fields in the Merge process but there are sonme we may want the data from so I didn't delete them.  How do I stop fields from being Required in this process?  The same thing happens when I create or edit a form in ArcPad Studio and then transfer it.
Answer: This is an old question, but: you can't. Shape file fields are not nullable. So either use check in/check out through the AP Data Manager to use a file geodatabase or just type blanks or 1s into the fields you don't have values for.


Why is carrot juice so sweet?

Question: Certain brands of carrot juice taste sweeter than any raw carrot I've ever eaten, yet are made only with carrots, with no added sweeteners. Are carrots sold in supermarkets just not ripe enough?
Answer: If you juice your own carrots you would see how sweet carrots actually are.
When you juice a carrot, you are extracting the liquid portion (which contains the majority of the sugars) from the cellulose. Since the cellulose is somewhat flavorless — it tastes pretty much like paper pulp — you are essentially creating "concentrated carrot" flavor, which is why it tastes so much sweeter than when you eat it whole.
You can also roast a carrot and see how sweet it is. Roasting drives off a lot of the water and breaks down the fiber. Try it; you'll see just how sweet a carrot actually is.
Answer: Also, the carrot is one of the only vegetables that contains that much sugar. Most vegetables consist of around 2 grams of sugar per 100g, while carrot is at 5 grams.
Comment: Not so. Using the USDA nutrient database, I checked out various vegetables. Some are used as juices too. 100 grams raw carrot contains 88.29 grams water and 4.74 grams sugar. 100 g raw beets contain 87.58 g water and 6.76 g sugar. 100 g raw parsnips contains 79.53 g water and 4.80 g sugar. Also containing more sugar than carrots are sweet onions, fresh corn and green garden peas. Carrots beat sweet potatoes and winter hubbard squash but not by much.

Why is carrot juice so sweet?