"Datumbazo" or "Datenbazo" - which one should I use?

Question: When I was looking for how to say relational database in Esperanto - rilata datumbazo I came across the alternative datenbazo. What's the difference and what speaks for the use of datumbazo in favor of datenbazo?
Answer: According to PIV, datumo (the basis of datumbazo) and dateno (the basis of datenbazo) are synonyms, so I would assume datumbazo and datenbazo are also synonymous. However, PIV does not contain datumbazo, and says that datenbanko is preferable to datenbazo.
However, I personally rarely hear datenbazo, and komputeko.net, which is generally a good source for computer terminology does not contain it. Also, searching datumbazo in Google yeilds 5,920,000, while searching datenbazo only gives 228,000 (datenbanko only gives 6,500), which tells me it is more commonly used.
You could, then, argue for whichever you like the most - there's nothing about relational databases in the Fundamento. I assume that PIV prefers dateno/datenbazo/datenbanko is because it's easy to assume that datumo = dat (date) + um + o, which doesn't really make logical sense.
Answer: Personally I have never heard the word datenbazo, to my recollection. Datumbazo strikes me as being very common and is the word that I always use for this.
I had never known the word dateno, only datumo, so to my eyes "datenbazo" looked almost like the word "dato" receiving the accusative of direction (-en) and joining with "bazo", which created (to my mind) kind of a strange nonsense word. I wouldn't say this is a strong argument against the word dateno, its a legitimate synonym after all, but if you're going for easy comprehension I though I'd just mention that for me (and so I'm guessing for the average Esperanto speaker, though of course I could be wrong), datumo is a more quickly recognized root.
Comment: The problem is, that one should no longer see any connection between data as in database and date as in date stamp. They are nowdays two completely different things.
Answer: The origin of the word "data" is in the plural form of the Latin word "datum" (a given thing → many given things). From that it was taken to denote "identifier given to a day", a datum, many data.
When computer programming was invented, one needed a word for input that was given to the programs. The chosen word was the Latin-based "data", the given things.
However this created a couple of issues in some, especially Indoeuropean, languages.

What is the singular form of the programming related word "data"?
Does the word "data" relate to programming or dates or is just a Latin word?

There is no excuse to repeat this mix-up in Esperanto. Therefore the root dat/ (and thereby its derivatives datumi and datumo) should be restricted to day/date (according to that interpretation datumbazo is a collection of date stamps ,say, in a logging system). For data in the general programming sense one should use a completely other root, like daten/ (so datenbazo is a database capable of containing different kinds of data).
When it comes to whether use bazo or banko, many people (me included) within the computer science make a separation between these. A databank is a general term for storing data, while it can be and usually is somehow ordered for the data to be programmatically retrievable, it's not as ordered a database, which has a separate system (a database management system) for defining, manipulating and retrieving data.
Answer: Between those two datumbazo is probably the more widely used. But ... it doesn't make much sense as a compound.
So, I would recommend datumbanko if you feel brave enough and can afford being a bit different. Words should be understandable if you know each element, and datumbanko delivers.
Comment: In science one needs exact terms. It's a really pitty, that there are no official boards for scientific terms in Esperanto (or if there are, they aren't working at sufficient speed). As I said in my answer, many make a separation between concepts of database and databank. It would be a poor decision for Esperanto not to make that too.
Comment: @JuhaMetsäkallas I don't know why the downvote. It is not ME the one saying that, it is PIV. It would strange to accept PIV only when it fits you and downvote people who cite it when it doesn't aggree with you: [datenbanko](http://vortaro.net/#datenbanko) (note _banko_): _Datenaro, organizita por ke la datenoj estu facile k rapide troveblaj k eventuale ŝanĝeblaj: rilata datenbanko._
Comment: Eduardo, a downvote was a mistake by me, sorry. I have a great respect for PIV and quote it myself often.
Comment: There are four terms here: two for the modier (_dateno_ vs. _datumo_) and two for the basic element (_banko_ vs. _bazo_). I prefer _dateno_ for the former for the obvious reason, that it is not related to date, as it shouldn't. While the German term is _Datenbank_ (→ _datenbanko_?), English and some other languages make a difference between a databank and a database. Databank is a general term for an organised collection of data (_datenaro_), while database is a more specific organised collection of data making it manipulable by a database management system.


Xfce4 Panel Launcher Menu as Desktop icon

Question: I'm trying to create a launcher like the one you can add to the panel on the desktop in Xfce. There is a create launcher option I'm aware, and the launcher is the same as one on the panel, but the difference is the panel plugin that allows you to add a group of applications to a launcher and such. I'm doing this for my dad and I've already written a .desktop file that makes an icon that opens the applicationsmenu plugin at the pointer once the icon is clicked, but I can't reuse the code from it. Hope anyone can give some help, thanks.
Answer: Before you log in, there is a button right next to the password prompt which allows you to select it on-screen.
Once you are in, the best way to switch is to log back out then make the other selection.
<code>They cannot run at the same time on the same console.
</code>
I do know that when I use VNC to open a second console I can get the xfce desktop.
Each console will have only a single environment.
So perhaps you could create an icon that launches VNC into your own machine.
Comment: I'm sorry? That has nothing to do w/ it, I'm trying to create a grouped launcher like you can on the panel on the desktop by creating a .desktop file that works. Nothing to do w/ logging in, I'm very confused. I know how to switch Desktop Environments.


Why might there be a sizable population of feral dogs in a poor country where food is in short supply?

Question: Consider a country in the third world where there is a lot of hunger and poverty. Suppose that there are no laws or customs against killing dogs, that firearms are somewhat common (say, 20% firearm ownership rate), and that almost everyone has an axe or a machete. Why might there persist sizable populations of feral dogs in both urban and rural areas? One would think that hungry people would quickly hunt the dogs to extinction. A determined group of humans armed with machetes and axes should be able to corner and kill a dog without too much issue, anyone with a gun should be able to do it even easier, and leaving out food spiked with pesticides should also do the trick. As meat is likely to be a rare delicacy in such a country and as even a single dog likely contains tens of thousands of calories, hunting dogs seems like it would be a logical option in such circumstances. So why would would dog hunting be rare in this country?
Comment: Why wouldn't there be such a sizeable population? Have you look to check whether, I don't know, India or Afghanistan have large numbers of feral dogs? (Hint: they do.)
Comment: iam not sure your meaning about hunting dog here is what i think, but dog is good in helping hunting though rather than get hunted, personal sentimental reasons, also seems they are far better as guard against another human attack or robbery considering the location seems dangerous, most feral dog has disease or parasite as Lime says since most feral dog usually eat trash if in concrete town or city.
Comment: also dog is good as scavenger too, i heard thats one of the reason beggar (iam not sure the correct english term, cant remember it at the moment, but what i mean is people that dont have house) adopt dog to help scavenge food faster before it get spoiled or the trash already gone regarding concrete town or city.
Comment: for the pesticides trick, you would need a pesticide that doesn't taint the meat.  Not likely.
Answer: Dogs are sacred or otherwise culturally taboo.
In the US people would need to get really hungry before they would start eating dogs, and that's just due to general affection. If they were sacred, like cats in Egypt or cows in India, the taboo would be much stronger.
Some authority prevents it
Not worth killing a dog if your totalitarian government is going to kill you if they find out.
Disease or parasite
If even 10-20% of dog meat carries a life-threatening parasite/disease, it wouldn't be worth eating them except in life-or-death circumstances.
Comment: An addition to these: people are vegetarians.
Answer: Various possibilities:

They eat domestic dogs instead. Feral dogs are domestic dogs which have gone wild (obviously). If you want to eat dog, it is much easier to keep a few in a pen, feed them on scraps and kill one for meat when you need it, than it is to go hunting a pack of feral dogs. You don't even need to feed the domestic dogs on meat. IIRC one of the Polynesian cultures fed their dogs on fruit, because they said the dog meat tasted better that way.

The population of feral dogs is constantly replenished from the population of domestic dogs. Unwanted dogs are turfed out onto the streets. Dogs run away from owners they don't like. Owners just let their dogs run free, and some of the bitches will decide to have their litters away from the owner's house.

You can't tell if the dog is feral or free ranging, and people get mad at you if you kill and eat their property. As recently as the 1970s there were packs of dogs running lose on the streets of some of the UK's cities - these were a mix of feral dogs and free-ranging owned dogs. If your society doesn't have rules and regulations saying that your dog has to have a collar, a microchip, be spayed and/or you need a dog licence to own one, then you can't tell if that scruffy mongrel is a feral dog or has an owner.

There is something horrible you can catch from eating feral dog meat. Rabies. Liver fluke. Galloping space lurgy. Invent a disease - or the belief of catching a disease - from eating dog meat. Perhaps everyone 'knows' that you get malaria if you eat dog meat in the wet season, because they are clueless about mosquito bites passing on a parasitic infection.

The dogs know they are being hunted. Feral dogs (and feral pigeons, urban foxes, ducks in the local park, etc) aren't wary of humans because 99% of humans ignore them. If the dogs are regularly hunted, then they'll make themselves scarce. They'll become nocturnal. They'll flee from humans the way wolves and deer flee in areas where they are regularly hunted.

The people have hunting laws/customs designed to avoid the dogs being hunted to extinction. If the dogs are a valuable source of protein, there may be customs to try and prevent them being hunted to extinction. These customs may, of course, break down in a famine.

The dogs breed faster than humans can wipe them out. Possibly the dogs just out breed the humans' hunting efforts. Or the dog population may indeed be on a downward spiral, but it is a slow and steady one, not extinction in one person's lifetime. Great-grandpappy bores everyone with his tales of how there were thousands of dogs on the streets in his youth, when plainly you can see that there are just hundreds.
Answer: There were many more people in the recent past.
This country has suffered a war, genocide or disease event which has depopulated the countryside.  The abandoned farms and orchards support large numbers of rats and deer and the feral dogs live on fruit and rats.  There are really a lot of dogs in the countryside and population pressure pushes them into the city.
Population density is high in the city and any city with a high population density will also have many rats.  The dogs moving in from the countryside are accomplished ratters and can sustain themselves thus.  People do try to shoot them when they can find them.  These dogs are stealthy, nocturnal and fast, much like coyotes.
As regards rifles, if I woke to hear some idiot shooting at dogs in the alley outside my house, I might be inclined to get mine and shoot him.  Walls are too thin to keep out bullets.
Answer: Infected Meat
The dogs carry a bacteria which is harmless to the dog, but harmful to people who eat their meat.
There is no reason to exterminate all feral dogs but also no reason to eat them.


i installed ubuntu but i want to go back to windows 8

Question: My laptop had windows 8 preinstalled and then i installed ubuntu 14.04. But now I want to reinstall windows 8 and dual boot the two but I don't know how to get my product key or get the windows 8 iso file. I heard that windows 8 has the product key in the BIOS but I don't know how to access it to download the windows 8 iso file. Do I have to purchase another copy of windows 8 in order to do this ?
Comment: Only your specific vendors version will work with your key. Many vendors will ship you a copy for a nominal charge. Some do not.
Answer: You don't need to have the key prior to installing Windows 8 - it will read the key from BIOS by itself.
I have not looked for a downoadable ISO for Windows 8 (there may be some) but ordered a windows 8 disk from Dell - they shipped pretty quickly, and provided a clean install.
Answer: Be careful! It can be dangerous to install Windows after some other OS. The Win bootloader might mess up your partitions:

A Windows OS should be installed first, because its bootloader is very particular and the installer tends to overwrite the entire hard drive, wiping out any data stored on it. If Windows isn't already installed, install it first.   - quote: help.ubuntu.com

The easiest and safest way is to reset the computer to its original state and then install Ubuntu as dual boot.
If a PC has Windows preinstalled and no backup-cd shipped with it, there usually is a backup software included. If not, you should be able to get a free backup cd from your vendor.
A very useful site about all this is here:
https://help.ubuntu.com/community/WindowsDualBoot


How does the .NET CLR work?

Question: I've been searching this on net, but could not find one in layman's language. Can anyone help me out?
Answer: If you want a Layman's description, I would go here: http://en.wikipedia.org/wiki/Common_Language_Runtime
That's about as simple as it can be explained in Layman's terms, with plenty of links defining terms a layman may not be familiar with.
Answer: For me the best definition is in CLR via C#, though to class that as a book describing things in Layman's terms would just be wrong! However, the Wikipedia definition seems simple enough to understand.
Comment: I've translated the CLR via CSharp, 3rd Ed to Persian language, I strongly recommend you to read that in depth to know what's behind the scenes.
Answer: You may find this a useful introduction from TheServerSide
link text

How does the .NET CLR work?


A person who is resistant to temperatures — what do you call them?

Question: What is the word for a person who through training becomes, or just naturally is, resistant to high or low temperatures? For example, the people who are able to meditate naked on an iceberg or something.
Comment: Probably a [duplicate](https://english.stackexchange.com/q/402557/365490)
Answer: According to Wikipedia it depends on why the person has resistance.
If the person keeps it's body temperature within acceptable boundaries despite external temperatures, the person is thermoregulatory.
If the person

simply adopts the surrounding temperature as its own body temperature

it is thermoconforming.
In your example, with meditating on an iceberg, I would guess the person is thermoregulatory, as (s)he keeps his/her temperature within certain boundaries despite the environmental temperatures.
Comment: Upvote because I learned some awesome words today.
Answer: The word for people who can withstand very high temperatures is "a salamander".
OED

1. a. A lizard-like animal supposed to live in, or to be able to endure, fire. Now only allusive.

1340   Ayenbite (1866) 167   Þe salamandre þet leueþ ine þe uere. [=The salamander that lives in [the] fire.]

1864   C. Kingsley Roman & Teuton iv. 131   That he will henceforth [in the isle of Volcano] follow the example of a salamander, which always lives in fire.

2. transferred and figurative applied to persons, etc. with reference to sense 1a.

a. gen.
1600   S. Nicholson Acolastus his After-witte sig. F4   I sate too hot, yet still I did desire, To liue a Salamander in the fire.

1888   F. Hume Madame Midas i. iv. 33   Madame Midas..was a perfect salamander for heat.

NB It is not "... how do you call them?", it is "... what do you call them?"
Answer: "Bothered".
Joe is not bothered by the cold.
Mary is not bothered by the heat.
Comment: So wouldn't that be ***unbothered?***
Answer: The nature of being capable of surviving under extreme environmental conditions or temperatures:
temperature adaptability or body temperature regulatability (Sounds like an abnormally formalized scientific phrase).
These are probably my very personal neologisms but are likely to be neologically acceptable and grammatically correct (I assume).  (:
Answer: A somewhat hyperbolic term for a person like this would be to call them an extremophile. Extremophiles are organisms (typically microorganisms) that can survive or thrive in conditions that are normally inhospitable to humans, whether that's in environments of extreme heat/cold/pressure, in a vacuum, or in a chemical environment that would be lethal to humans.
This term typically describes non-human organisms, although one could hyperbolically apply the term to a human who is comfortable in extreme conditions. If the person does actually display a superhuman environmental fortitude, like surviving without clothes or shelter for a long duration in a freezing environment, the term becomes even more appropriate.
Answer: Impervious to hot and cold, is how I would phrase this.


Comparing standard deviations of two dependent samples

Question: As far as I know you can do a F-test ($F = s_1^2/s_2^2$) or a chi-squared test ($\chi^2 = (n-1)(s_1^2/s_2^2$) for testing if the standard deviations of two independent samples are different. But does this also hold for dependent samples?
Comment: In some situations an F test or $\chi^2$ test will work as expected and in others they won't, depending on how the data are assumed to depart from independence.  In what way, precisely, do you suppose your two samples are dependent?
Comment: Have you checked the Morgan-Pitman-Test? I rarely see it mentioned, and I have no information on its strength and weaknesses. Still, it seems to be a test for the equality of variances in two dependent groups.
Answer: The Morgan-Pitman test is the clasisical way of testing for equal variance of two dependent groups.
For $n$ pairs of randomly sampled observations
$(X_{11}, X_{12}),...,(X_{n1},X_{n2})$
define
$U_i = X_{i1}-X_{i2}$
and
$V_i = X_{i1}+X_{i2}$
for $(i=1,...,n)$.
Then under
$H_0: \sigma_1^2=\sigma_2^2$
the correlation of $U$ and $V$ is zero.
If the distributions of the two variables differ in shape then you should use a robust method of testing the hypothesis of $\rho_{uv}=0$.
A good description is in Wilcox's Modern Statistics for the Social and Behavioral Sciences (Chapman & Hall 2012), including alternative ways of comparing robust measures of scale rather than just comparing the variance.
Comment: This misses the important assumption of bivariate normality of $X_1$ and $X_2$.


Magento 2 minicart translation issue on some browser

Question: I have Magento 2.2.5 website running successfully, but I am facing one serious issue on Minicart section and add to cart button. Everything get translated but on some browser like chrome and safari minicart and add to cart button are not translating. Can any one help me to fix this issue.
Website URL
See here too
Answer: It seems like all your JS-translations are not working, are you using a translation-pack for the DE translations?
Comment: Yes I am using all the translation. If JS-translations are not working then why all translations working fine on Mozila but not on Chrome browser.
Answer: I faced the same issue with the sites that have translation csv in their custom theme. I couldn't find the best solution for it or the reason behind it. I found a work around for it. You can activate inline translation and manually translate/override that button.
Go to admin->store->configuration->advanced->developer. In translate inline, set enable for storefront to yes. Save config and then flush cache.
Go back to your site store front and edit the translation for add to cart button. Then with the same path on admin set enable for storefront to no. Save config and flush cache.
This will fix the issue but there is a draw back in it. The translation for that button may break time to time when you deploying static content. One way to fix it is to flush Static file cache & then flush Magento cache.
Basically this is not the best fix for the issue but it is a workaround.
Comment: You have the same problem I mean on chrome browser minicart not translated and on Mozilla it translated?
Comment: well not exactly, when piece of translation breaks (like the `Add to cart` button) it is not translated in Chrome or Firefox.
But if it is just related to chrome, may be it is because of site data and caching of chrome.


3 balls drawn from 1 urn - probability all same color (with/without replacement)

Question:
An urn contains 5 red, 6 blue and 8 green balls. 3 balls are randomly selected from the urn, find the probability that they are all of the same color if:
(a) the balls are drawn without replacement;
(b) the balls are drawn with replacement.
Comment: what have you tryed?  Hint: P(all 3) = P(drawing one of color a)*P(drawing another of color a)*P(drawing yet another one of color a)
Answer: $1.$ With replacement: There are three ways this can happen, red, red, red; blue, blue, blue; and green, green, green.
The probability of red, red, red is $\left(\dfrac{5}{19}\right)^3$. Find similar expressions for the other two colurs, and add up.
$2.$ Without Replacement: The probability of red, red, red is $\left(\dfrac{5}{19}\right)\left(\dfrac{4}{18}\right)\left(\dfrac{3}{17}\right)$. Find similar expressions for the other two colours, and add up.
Remark: We could also do the problem by a counting argument. Let's look at the first problem. Put labels on the balls to make them distinct. Then for with replacement, there are $19^3$ strings of length $3$ of our objects. (The three objects in the string are not necessarily distinct.) All of these $19^3$ strings are equally likely.
There are $5^3$ all red strings, $11^3$ all blue, and $8^3$ all green. This gives probability $\dfrac{5^3+6^3+8^3}{19^3}$.
One can do a similar calculation for the without replacement case.
For without replacement, there is a third approach. We can choose $3$ objects from $19$ in $\dbinom{19}{3}$ ways. And we can choose $3$ of the same colour in $\dbinom{5}{3}+\dbinom{6}{3}+\dbinom{8}{3}$ ways.


Rotary Encoder - Unexpected output

Question: I'm seeing unexpected data on the A & B outputs of my ALPS incremental rotary encoder. The A & B pins are are attached to a microcontroller with pull-ups enabled and the centre pin is ground The pulses are aligned on their rising or falling edges rather than being 90 deg out of phase as I expected (and documented everywhere). Attached are two capture screenshots, one for clockwise the other anticlockwise rotation. Am I missing something?
Comment: Looks like channel 1 is getting ANDed with channel 2. If it were a simple short, I'd expect both would rise or fall together, so I think the fault is more complex. If you have other pins available on the MCU, try the same setup on different pins; if it's the same, try another encoder.
Comment: You are missing the all-important link to the data sheet.
Comment: Link to [datasheet] (https://docs.rs-online.com/8546/0900766b810a5d53.pdf)
Comment: I've tried connecting to other pins on the microcontroller, same output. Only have the one encoder to hand.
Comment: Which specfic part number you have, and does it match to what you ordered? Are you sure it is not a wrong part with absolute output?
Answer: You have, most likely, connected pin A or B to ground instead of C.

Figure 1. Encoder pinout. (Click to enlarge.)

Figure 2. (1) Encoder ABC. (2) Push-button pins.
Now that C is the centre pin.

simulate this circuit – Schematic created using CircuitLab
Figure 3. In (a) 'A' requires both switches to close before it will pull low. This will occur 25% of the time. 'B' just requires SW2 to be closed to pull low. This will occur 50% of the time.
Comment: Nice catch! +1.
Comment: Genius! - That's exactly what it was

Rotary Encoder - Unexpected output


How do I add accented characters to PDF info without using hyperref?

Question: Using pdflatex, I'm looking to add PDF information into by document, including an accented name (Rónán Daly). Normally I'd use hyperref to do this; however, the conference I'm submitting to is complaining about generated links and bookmarks - I can stop the generation of bookmarks, but not links. So I'm looking at the option of using \pdfinfo, with /Author, /Title and /Keyword. However, I can't seem to add the accented characters correctly. I'm currently using ASCII, but could change this if necessary. Any ideas on how to solve either of these problems?
Comment: Welcome to TeX.SX! How are you inputting the accented letters? You can edit your question to show it; particularly important is what input encoding you're using.
Comment: Ulrike's solution is probably the best one for your problem, but I just wanted to point out that hyperref has the option `hidelinks`: "Hide links (removing color and border)". The links are still "clickable" but you no longer see the links (link-border or link colour). Once I had the same issue with an editor, who was satisfied with hidden links.
Comment: Normally this would the solution I would use, but I should point out that this was not an option in my case, as the pdf was being scanned automatically to find links and bookmarks and was hence being rejected by the submission system; with hidelinks, the links are invisible, but still present.
Answer: This works:
\documentclass{article}
\pdfinfo{%
/Author(R\string\363n\string\341n Daly)/Title(blub)/Subject()}

\begin{document}
abc

\end{document}

Comment: In addition to Ulrike's answer, you can find a table of 3-digit codes to be used after `\string` here: http://www.pjb.com.au/comp/diacritics.html, under the column header `Octal`.
Comment: Brilliant, this works perfectly!


GUI Builder for Eclipse Juno

Question: Do you know any GUI builder for SWT, which is compatible with Eclipse Juno (4.2)?
Answer: The correct entry site for the window builder would be http://www.eclipse.org/windowbuilder/. The Google update sites still work, but the Window Builder is now an Eclipse project, and the main update sites are hosted at Eclipse. There you'll find also the link to the official update site for Juno (http://download.eclipse.org/windowbuilder/WB/release/R201206261200/4.2/) and a link for a ZIP download of the update site.
Answer: Uh... this one was quick. Nevertheless I'll leave this question for everyone, who encounters the same problem, because as for now there are quite few or none official GUI builders for Juno.
I was misguided by the Window Builder download site (https://developers.google.com/java-dev-tools/download-wbpro), which does not include a link for Juno. Attempt to install the 3.7 version in Juno will fail.
However, it seems, that repository for Juno actually exists. The trick is to modify the repository URL:
Name: Window Builder Plugin
URL: http://dl.google.com/eclipse/inst/d2wbpro/latest/4.2
Window Builder then installs correctly.

GUI Builder for Eclipse Juno


Tools for retrieving and modifying multi-value attributes in Microsoft ActiveDirectory

Question: Most attributes in MSAD are single-valued and pose no problem.
I am familiar with the dsquery user -samid jdoe | dsmod -webpg "http://some.url/" method. However, some attributes are multi-valued, such as telephone number and webpage. These values can be managed through the Active Directory Users & Computers Microsoft Console (dsa.msc) via the dialogue shown by clicking on the "Other..." button, but I'd really rather script the modifications. It seems to me that dsmod & dsget do not support multi-value retrieval and editing; only the first value of the set seems to be accesible.
  Am I correct? If I am not correct, I would appreciate a syntax example. If I am correct, would you please recommend an alternative scriptable tool that can handle multi-value attributes? The more "official and supported" the tool, the better.
Answer: Have you taken a look at PowerGUI? It's a good at making mass changes to AD since it manipulates powershell under the hood.
Comment: Thanks for your suggestion. I'd never heard of PowerGUI, havent' quite yet dipped into PowerShell. We're overdue for that, I suppose. We already use Quest's TOAD product and have been happy with that, and I see that PowerGUI is also a Quest product, so now I'm really intrigued.
Answer: First, -webpg isn't the multivalued list of web pages.  Using the webpage other button in the GUI, that list of websites is call url.  To query it:
dsquery * "<full dn>" -l  -attr url
test2
test

However dsmod doesn't have a way to modify it.  PowerGUI may work, I use admod.
admod -safety 1 -b "full DN" "url:+:test3"

Then, I can do the query again and see the new value:
dsquery * "<full dn>" -l  -attr url
test3
test2
test

You can browse the full schema to find the LDAP name of other values.
Comment: Thanks, you hit all my main points, and corrected me on distinction between webpg and url attributes. I regret to hear that MS does not have a suitable "official" option, but it looks like the extant third party stuff will be good tools and have good reputations.


Can blood that has had an anticoagulant added to it be boiled without coagulating?

Question: If I understood the information I've found elsewhere correctly, you can't boil untreated blood without it coagulating, right? But what if you added an anticoagulant to it? Would it be possible to boil that blood or would it coagulate in spite of it? Thank you in advance!
Answer: Coagulation, or clotting, is a proteolytic cascade that generates an insoluble fibrin based protein net, or mesh.
Anticoagulants are things like EDTA (?) that chelate divalent cations required for the clotting cascade.
Boiling blood will denature most, if not all, of the soluble serum proteins, forming an insoluble precipitate.  This is structurally different from a blood clot.
Think about what happens to the white part of a chicken egg when you boil (or heat) it.  That is protein denaturation.


Multiple Site Manager Can't Add Site EE 1.6.8

Question: I need to add two sites to my Multiple Site Manager in Expression Engine 1.6.8.  There are 24 microsites already.  The first I added, and it looks ok, but I do not get the "Create a New Site" link when I go to "Edit Sites".  I'm worried that the database has too many columns or something like that.   Any suggestions?
Comment: 6 year old EE? It'll only get worse if you don't work on an upgrade path. And with new versions of PHP coming out, you're continuing to fall behind. Not trying to be a jerk, but I would highly suggest you push your employer to upgrade. It's only going to get harder, and when something really breaks, upgrading and fixing it gets exponentially harder as time goes on.
Answer: Perhaps you run out of number of available sites for your MSM license. Check that in your purchases section on EllisLab's site.
Not sure though you'll be able to purchase more, as EE1 is not supported officially anymore.
Comment: You can still buy additional sites for MSM/EE 1, yes. That said, upgrading to EE2 should really become a priority.


Reading PDF in C#

Question: I want to read and display the contents of the PDF files into my RichtextBox. I am using windows application C#.  Is it possible?  What is the way to do it?
Answer: You can use Adobe PDF IFilter Library to convert a PDF document to text.
Also see an example on the CodeProject
Answer: iTextSharp is another alternative PDF library for .NET.
Comment: Does iTextSharp allow one to read PDF and convert it to RTF though?
Answer: Since PDF is an binary format you'll have to use a pdf-library like pdflib  in order to read pdf-files.
pdfLib
Answer: You should checkout PDFSharp library and they have preview component, where else extracting text and showing them in RichTextBox could be little bit of more work, but you can try this.

Reading PDF in C#


How to declare generic event for generic delegate in c#

Question: I have a user control which deals with fileupload. I have defined a delegate as follows
public delegate void FileUploadSuccess<T>(T value,FileUploadType F)

value can be a string as well as byte array. FileUploadType is an enum which tells which type of file was uploaded.
Now I have declared a event in usercontrol to raise this.
public event FileUploadSuccess<string> successString;   //In case I want a file name

public event FileUploadSuccess<Byte[]> successStringImage;  // In case I want a byte[] of uploaded image

What I wanted was a generic event
public event FileUploadSuccess<T> successString.

Answer: Except as part of generic types (i.e.
class Foo<T> { public event SomeEventType<T> SomeEventName; }

) there is no such thing as generic properties, fields, events, indexers or operators (only generic types and generic methods). Can the containing type here be generic?
Answer: That's impossible unless you define your type parameter in an enclosing class. For example:
public delegate void FileUploadSuccess<T>(T value, FileUploadType F)

public class FileUploader<T>
{
    public event FileUploadSuccess<T> FileUploaded;
}

But this only moves your problem to another location, since now you would have to declare two instances of the FileUploader class:
FileUploader<string> stringUploader = new FileUploader<string>();
FileUploader<byte[]> stringUploader = new FileUploader<byte[]>();

This may not be what you want.
Answer: To the outside world, an event in many ways looks like a field of the class. Just as you can't use an open generic type to declare a field, you can't use an open generic type to declare an event.
If you could leave the type open, then the compiler would have to compile in the event handler add and remove code for every possible type for your generic parameter T. A closed generic type can't be JIT compiled, because your event is not a type in its own right, rather is a part of an enclosing type.
Answer: Why do you need a generic event? Can't you just use a normal event:
public delegate void FileUploadSuccess(object value);

and then
public event FileUploadSuccess Success;

In the Success event handler you will know the type of the object being passed:
public void SuccessHandler(object value)
{
    // you know the type of the value being passed here
}

Comment: Sir, I wanted to make it type safe and thought if generics could help.
Answer: I don't think this is possible.
Event is like an instance of a delegate (roughly speaking), and an instance is a concrete implementation ( of a generic or a non-generic class).
For better understanding of delegates and event, you can refer to this SO discussion.
Answer: There is a generic EventHandler class in the .Net Framework just for this purpose:
using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Counter c = new Counter(new Random().Next(10));
            c.ThresholdReached += c_ThresholdReached;

            Console.WriteLine("press 'a' key to increase total");
            while (Console.ReadKey(true).KeyChar == 'a')
            {
                Console.WriteLine("adding one");
                c.Add(1);
            }
        }

        static void c_ThresholdReached(object sender, ThresholdReachedEventArgs e)
        {
            Console.WriteLine("The threshold of {0} was reached at {1}.", e.Threshold,  e.TimeReached);
            Environment.Exit(0);
        }
    }

    class Counter
    {
        private int threshold;
        private int total;

        public Counter(int passedThreshold)
        {
            threshold = passedThreshold;
        }

        public void Add(int x)
        {
            total += x;
            if (total >= threshold)
            {
                ThresholdReachedEventArgs args = new ThresholdReachedEventArgs();
                args.Threshold = threshold;
                args.TimeReached = DateTime.Now;
                OnThresholdReached(args);
            }
        }

        protected virtual void OnThresholdReached(ThresholdReachedEventArgs e)
        {
            EventHandler<ThresholdReachedEventArgs> handler = ThresholdReached;
            if (handler != null)
            {
                handler(this, e);
            }
        }

        public event EventHandler<ThresholdReachedEventArgs> ThresholdReached;
    }

    public class ThresholdReachedEventArgs : EventArgs
    {
        public int Threshold { get; set; }
        public DateTime TimeReached { get; set; }
    }
}

source: https://learn.microsoft.com/en-us/dotnet/api/system.eventhandler-1


In "Utopia", how does Martha know the Master's voice?

Question: In "Utopia" of the new Season 3, as the Master has regenerated, Martha states that she recognises the voice from inside the TARDIS.  How does she know the voice?
Comment: Piece of advice: I'd be careful with asking DW questions to episodes you're watching, as the answers can easily spoil a lot of subsequent episodes for you. Especially in the seasons that lie before you.
Comment: Yeah, I've actually watched all the new ones and was re-watching season 3, and that bit confused me.  Thanks though :)
Comment: Since the Master posed as Saxon during the present day, maybe it was like one of those "changing the future" things, where things have just "happened."
Answer: Because

 The Master, after regenerating, goes back to the past, 18 months before the 2008 elections, and assumes the identity of Harold Saxon, who will be candidate to become Prime Minister. Therefore, The Master was already in the UK before the fall of Harriet Jones, meaning that Martha could have heard him while in campaign, in the news, or so.
Comment: Heh, I then watched the next two episodes and was (facepalm) that answered that one.  Cheers for the quick response.


Is there any danger to my devices in testing possibly-bad cables?

Question: I've been cleaning out my room lately, and in the process I've dug out several cables, both MagSafe and Lightning, in various states of disrepair. I want to plug them into my devices to see if they still work, but I need to know: Is there any risk of seriously damaging them if a cable turns out to be bad?
Comment: This question should really be on SuperUser. It is applicable to all devices, not just Apple devices.
Comment: @dotancohen Sorry. I figured that it belonged here because of the specific cables in question.
Answer: Yes - lightning carries decent amount of power. Crossed wires could short out a device. MagSafe - worse - more power, less room for error. The only upside there is the MagSafe in side of things is a bit more robust since it handles more power and if you blow the MagSafe on the Mac, it's a relatively inexpensive repair.
Fixing the phone connector would be far more costly.
That being said, the change of damage is low and if you have lots of cables and can make money on them, the risk might be worth it even if you damage things and have repair bills.
Answer: I'm reluctant to touch this one with the limited information provided about the extent of damage, i.e. user assumes all risk.  That being said the Magsafe cable provides power from an AC source so it is theoretically possible that if there is serious damage to the cable or adaptor that it could lead to a short circuit or power surge.  The lightning cable provides data transfer and a lower voltage/power output which is modulated by the separate adaptor, not the cable. One would think there is less chance that the lightning cable would cause electronic damage.  Of course if the male lightning connector is physically damaged it could potentially damage the device upon insertion
Again, without the advantage of seeing the cables its hard to get more specific.
Answer: Yes, it may be dangerous. Cross wiring may short out your device.


Difference between redirect and iframe

Question: I want to know what is the difference between Magento v2.3.1 (iFrame) and Magento v2.2.3 (Redirect)
Comment: Can you explain your question a bit more, so that someone can try to answer?
Comment: i am trying to upgrade paygate extension.
Here there are two packages.
1. DPO PayGate Magento plugin v2.2.9 for Magento v2.3.1 (Redirect)
2. DPO PayGate Magento plugin v2.2.9 for Magento v2.3.1 (iFrame)

I am not getting which one to use
Answer: Both plugins work similarly. Only major difference is that after clicking 'place order', the iFrame version opens a popup and loads the Paygate payment form in an iframe within, while the Redirect version will redirect the customer away from the checkout page to a Paygate payment page.
Both versions will redirect to the Magento order success page after successful payment.

Difference between redirect and iframe


My master thesis supervisor refused to recommend me for a PhD

Question: He reasoned that I lacked the understanding of the subject and so not competent enough for a PhD. I agree to his concerns, since I was studying this concept for the first time (for my thesis) and was a bit slow in my approach. On the other hand I'm very passionate about this particular subject and intend to pursue an academic career in this field. I did manage to get a decent score in my thesis and graduated with cum laude. The question is should I give up and take up some job since nothing will move forward without a recommendation.
Comment: _I'm very passionate about this particular subject_ — Passion is not enough.  You actually have to be _good_ at the subject if you want any hope of pursuing an academic career.
Comment: With apologies to The Incredibles, **If everyone gets a recommendation, no one does** (because the recommendation is meaningless)
Comment: Agreed with @JeffE.  I want to be careful: we don't have nearly enough information to give you meaningfully discouraging advice.  However your advisor does, and what you say to counterbalance his assessment is not of equal weight.  Having a passion for academia is a necessary condition for an academic career but it is not enough: think how many people are passionate about, say, baseball and how few people become professional baseball players.  It is not rational to say "I *must* have an academic career, so I'll work towards it one way or another."  You don't need one and need not get one.
Comment: Try other advisors.
Comment: You could consider doing an internship before a PhD, to get a new chance of earning a recommendation letter.
Comment: You should still apply. I went to a for profit and was still accepted to a prestigious university because of my GRE score and strong application. (I did get many rejections for not attending a 4 year institution) but others made the exception. Plus you'd regret that you never attempted to make yourself an expert in the field you care about.
Comment: How can you graduate "cum laude" when your advisor obviously doesn't support that designation?
Answer: From what you've written, it sounds like your adviser doesn't think you know enough to be able to research a subject. Knowledge can always be learned. It's actually a very important trait for a PhD student to be able to sit down and learn what they need on their own.
There's no reason not to apply to PhD programs. It's going to be very hard to get into one without a letter from your adviser, but it's not theoretically impossible. The worst thing that can happen is that you spent some time and money and fail to get accepted anywhere. The best thing that can happen is that you get into a program and have the chance to follow your passion.
On advice from Pete L. Clark, I'm adding a caveat: You should be careful as to what sort of programs you're applying to and think carefully about whether those programs will lead to your desired outcome. Going into a PhD program is not something to be taken lightly. It will takes years of your life and be a potential drain on you mentally, emotionally, and economically. To land a decent academic position you need to graduate from  a top program and produce high level research. Afterwards you may have to put in more time and effort as a post-doc. Once you do finally get a position, you'll have to work your way through the tenure process.
Comment: "The worst thing that can happen is that you spent some time and money and fail to get accepted anywhere." I'm afraid I disagree.  I think it would be worse for the OP to be admitted to a poor PhD program, having to pay funding out of his own pocket, and spend up to ten more years realizing that he cannot complete the program and/or cannot have an academic career afterwards.  Anyone with a master's degree in something has already followed their passion in that thing and should have enough training to continue to do so on their own.  Almost no one wants a PhD and not a career that uses it.
Comment: "There are jobs out there that require a PhD. I'm assuming that OP wants one of those." There is no need to assume: the OP says he wants an academic career.  It is an empirical fact that only the upper echelon of PhD students can have a successful academic career. "I'm also assuming they're smart enough to drop out of the program if it goes poorly." After how many years and how much of their own money do you assume it will take for someone to drop out?  And what will the indication be, if it is more serious than their thesis advisor recommending that they not continue?
Comment: I agree (and said in a previous comment) that we cannot know whether the OP is suitable for an academic career.  But you seem to advise **everyone** who is interested in an academic career to attend whatever PhD program will admit them.  I think that is not just bad advice but rather irresponsible.  Certainly anyone contemplating a PhD program and an academic career should take steps to evaluate the chances of success.  The OP should take more steps in his evaluation, not fewer.
Comment: I disagree. There are jobs out there that require a PhD. I'm assuming that OP wants one of those. I'm also assuming they're smart enough to drop out of the program if it goes poorly. The only indication that OP is not a good fit for a PhD is that one professor said they lacked some understanding of a subject. Without knowing the full details, it's hard to read much into that statement.
Comment: @PeteL.Clark I've added a larger caveat to the end of my answer based on our discussion. Thank you for bringing those issues up.
Comment: I appreciate your revisions, and I have changed my downvote to an upvote.
Answer: While I was an undergraduate student at a lower ranked institution in my country, all the professors in the department were thinking that I don't have any academic merit. Just after that I took some time outside the school, and later attended classes at a top-ranked school in my country just as a visiting student.
I was the best in the class and the professor was overly blunt to state that fact in front of the other students. The people in my undergraduate institution were so biased and mediocre that they have never had an intention to give me a chance or were so insidious and sinister to undermine me.
So, sometimes, at some places you simply do not fit with others. You should try your chance at other places, internships etc. A single institution or professor does not suffice to assess your abilities.
A last note: some academics are real jerks, do not give up at the first obstacle.
Comment: I would suggested that you edit out the offensive part in the last sentence.
Answer: Letter of recommendation is not always mandatory for all PhD admissions. You could still apply for a PhD without it.
You might have to vouch for your talents in other ways to certify your ability. Eg., Online certification, skills development, and independent research.
Answer: Saying that you "lack understanding" seems like a really vague criticism, especially when you are working on a specific topic for the first time.  Ask other professors what they think.
Answer: There are two aspects of this.  One is Should I forget about a PhD? and another is Is this a show stopper?
But for both questions, a lot depends on the opinions of other elders in your department.  Are there other professors in your department who know your work, whom you could approach for career advice?
When you meet with such a professor, try to keep your questions open ended.  It's okay to express an interest in pursuing further studies, but in that preliminary conversation try to keep all options on the table, even if in your heart you feel a strong drive to jump straight into further studies.
Unless, of course, the professor asks you what your preference is.
Answer:
The question is should I give up and take up some job since nothing will move forward without a recommendation.

You are right, a recommendation from your thesis adviser plays an important part in getting a PhD position (experience!). But giving up is out of question if your words I'm very passionate comes from your heart. I strongly disagree with those who commented, one have to be good at the subject if you want any hope of pursing an academic career. It bear a high degree of vagueness with it because the terms good and hope are incredibly inappropriate in this context as it is not at all clear that OP indeed lacks the potential to be good at the subject.
I think you can do a couple of things here

Talk to your thesis adviser and ask him politely to explain why he thinks you are not apt for the recommendation.
Value your adviser's words and spent some time on working out yourself on the subject core.
If you think that your adviser misjudged you, try for a short term project position, which can be relatively easy to find even without your adviser's recommendation.

I think there are plenty of choices before you and tremendous room for improvement, once again in my humble opinion, its too early to give up.
Comment: Downvoted. I never said OP should give up.  Neither one of us knows whether OP is good—or has the potential to become good—at their subject or not.  Nevertheless I stand by my comment.  If you aren't _demonstrably_ good at your chosen field of study, you will not get an academic job.  Suggesting otherwise is irresponsible.
Comment: Is it out of the question for anyone who is passionate about space exploration to give up the idea of becoming an astronaut?  For anyone who is passionate about athletics to become an olympic athlete?  Disagreeing with the statement that you have to be good at the subject to succeed in academia is disagreeing with plain common sense.  Telling someone that you don't know that it is too early to give up is what is inappropriate.  If for instance all the faculty members the OP has ever interacted with think that he should not go to a PhD program, then he should give careful thought to giving up.
Comment: "Its clear that you haven't read the answer fully." I paid you the courtesy of explaining my downvote, and you replied with a bad faith assumption about me.  If you want people to be courteous to you, please be courteous in return.  For now I will not engage with the rest of your comments.
Comment: @Down voters, at least show the courtesy to let the answered know why you down voted.
Comment: @PeteL.Clark Its clear that you haven't read the answer fully. Of course one have to be good at the subject to succeed in academia. One may not be good right now. But that doesn't mean one *won't* be good, on the contrary he *will* be good if he have the potential and the passion to work hard for the subject.
Comment: I agree with @Sathyam Recommendations are important, but I would add that OP should ask from his/her advisor to write explanation statement, ( something like progress report) where all the points that are missing in OP knowledge and preparedness for PhD and overall Master progress will be in great detail explained, I dont know if in USA have this, but in my uni it is usual that every advisor write a report about positive and negative sides of their advisees


Any good C++ ide for MacOS

Question: I would like to know the best free c++ IDEs for MacOS Catalina. I would not like the limited xcode for c++. So please anything else.
Any help appreciated
Comment: Try Code::Blocks, I am not a Mac user and there are not many many developers for that OS, but the few ones say it should work.
Answer: For some reason my previous answer was deleted by Nicolas Raul, a moderator. No information as to why he would do that. He did asked for a more detailed answer on 01/13/22 in the comments, but then deleted my answer on 01/14 (??). Again, no explanation as to why.
Maybe he deleted it because he didn't like that I included JetBrains, because it's not free. However, JetBrains makes great IDE's for most languages, including C++. Specifically, their C++ IDE is called CLion but IntelliJ is their flagship product that can be used for nearly any language with the addition of plugins, most of which are free. PLUS, JetBrains offers free licenses for students, teachers, and opensource developers. They also offer a 50% off program for non-profits, startups, and educational organizations.
So, to answer Nicolas Raul's request, here's some more detailed info about the IDEs I listed, regarding C++
Eclipse: Totally free IDE. It includes plugins for C and C++, cross build plug-ins for Arm and RISC processors, debug plug-ins, compiler, build features, testing support, terminal, support for templates, and more.
NEtBeans: Granted, NetBeans was created originally for Java, it does support C++. It's all about configuration. You can build, run, and debug your project on the local host or on a remote LINUX/UNIX OS. If you have NetBeans, or need to use it for some reason, it can be done. And, NetBeans is maintained by the Apache foundation so you know it's in good hands. (here's a YouTube video to get you started with C++ configuration: https://www.youtube.com/watch?v=DamuE8TM3xo)
Atom: It's a free text editor/IDE that can be used for most popular languages. Support for C++ is available through the package manager, configuring plugins, and your OS. On the Mac you need XCode developer tools and gpp-compiler. Atom supports code hinting, debugging, autocomplete, and more. Here's a Youtube video to get you started with Atom: https://www.youtube.com/watch?v=ZkEVZ8LCtvg.
CodeBlocks: It's cross-platform, like most of those on this list (works on Windows, macOS, and Linux). It has all the basic features you want in an IDE; debugging, compiling, auto completion, profiling, code coverage, code analysis, and plugins that can enhance the dev environment.I think it's built with C++.
Visual Studio Code: *Note: I originally put a link for Visual Studio. I meant to add Visual Studio Code which is Microsoft's free IDE. And it's also available on Mac and Linus OS'es. C++ is supported with extensions with all the necessary IDE features--compiler, code hinting, debugging, deployment, etc. VSCode is a really good option for a lot of languages. Microsoft has done a good job with this IDE.
Since I posted last I found a few more free options. CodeLite, C++Builder, QT Creator, and of course the ubiquitous Vim (which can be configured for most any language). I'm not going to give details about these IDE/editors because I trust that StackExchange users know how to use Google and can do their own evaluation of IDEs.
I realize the details are super basic but every IDE basically offers the same features. Just in different interfaces. If you Googled C++ and the IDE name you will find more info. I recommend you install a few and try them out. Everyone has different opinions about what they want from an IDE. so, seriously, take the time to evaluate a few. You won't regret the time you spend to find the one you like.

Any good C++ ide for MacOS


Potentials and position uncertainty

Question: In the Schrodinger equation, we have some potential $V(x)$. But generally, there is some uncertainty in the position with solutions to Schrodinger's equation. Classically, we would say that a particle at position $x$ is associated with the potential at that point -- is there a quantum analog when the position wavefunction isn't localized? What's to say if a particle is in a potential or not if it doesn't have a well-defined position?
Answer: The schrodinger equation tells us that a particle interacts with a potential if its wavefunction has a non-zero amplitude in the region enclosed by the potential. That is to say, the wavefunction's time evolution is independent of the potential energy's value in regions where the wavefunction is zero.
However, the wavefunction may have non-zero amplitude in regions inside and outside the potential simultaneously. Therefore, we can not always say without performing a measurement whether or not the particle is inside or outside the potential.
Comment: What you've said is correct, but it doesn't really seem to answer my question. I'm wondering how we can say whether or not a particle should interact with a potential if its position isn't well-defined. I have a hunch that the answer lies somewhere in scattering theory, but the text that I've looked at gives a description of the position representation of the wave function scattering, which seems to be even more confusing since I thought that the wave function was just an abstract representation of the state, not representative of the actual position.
Comment: I think I understand your question better now. I rewrote my response.

Potentials and position uncertainty


Raster Calculator Bug at start

Question: I use ArcGIS 10.1 on a Windows XP. ArcGIS completely shuts down when I attempt to launch the "Raster Calculator" tool. Has this happened to someone else? Any ideas on how to solve this annoying issue?
Otherwise, can I calculate the sum of raster values using command-line GDal?
Comment: Windows XP? Have you accepted some sort of OS update? I've experienced problems in the past when Internet Explorer updates.
Comment: Does raster calculator also fail when you try and run it through model builder? ArcMap may have trouble launching the dialog itself, not the tool. Please test this and let us know results so we can help you troubleshoot. See this link for more information: http://forums.arcgis.com/threads/2005-Raster-calculator-in-ModelBuilder
Answer: GDAL will probably run better on Windows XP than ArcGIS 10.1.
Keep in mind that support from Microsoft for Windows XP is ending on April 8, 2014.  Not to say that arc won't work, but its harder to find people in the community to answer questions.
I would test this Raster Calculator issue myself but I upgraded my last xp box about a year ago (went with Linux Mint).
Best of luck.

Raster Calculator Bug at start


Banked and non banked memory

Question: I have this question of banked and non banked memory specifically for freescale s12x  controllers. They have both banked and non banked ram and flash memory. I know it will start putting first data in non banked ram, now suppose I exceed the limit will it automatically start putting in banked ram? If I have to take care then I feel I will loose the advantage of banked memory. Similarly for flash memory.
Answer: In the 68HC12A4, for example, there are two areas are available for data banking, the first from 0x7000 to 0x7fff (4KB) using the DPAGE register, and 0x0000 to 0x03ff or 0x0400 to 0x07ff (1K) using the EPAGE register.  Apparently the two EPAGE areas overlap (bit 10 of the address is a don't care).
With the Cosmic C Cross Compiler for the HC12/HCS12, a variable in the DPAGE area can be specified using the @far modifier on the declaration.  A variable in the EPAGE area can be specified using @epage and @far.  For example,
<code>@far int i;          // DPAGE area
@epage @far int j;   // EPAGE area
</code>
I don't think the compiler automatically starts using banked RAM after filling up non-banked RAM, you must use these keywords.
A variable can be located in the code bank using @far with the const keyword:
<code>@far const int k;        // PPAGE area
</code>
Such a variable can only be accessed in a function located in a non-banked area.
Similarly, functions are located in a banked area using the @far keyword.
<code>@far int func(void)
{
...
}
</code>
The syntax for other compilers (such as CodeWarrior) may vary, but they would have to use a similar mechanism.  Check your compiler manual.

Banked and non banked memory


Are there any `armv6j_hardfp` binary repositories for Gentoo?

Question: Since the Raspberry Pi hardware is non-ambiguous, the point of compiling optimized to the individual machine is pretty moot, while I'd still like to use Gentoo on my Raspberry Pi due to uts excellent capabilities to compile new software if necessary. So, are there any public binary repositories for armv6j_hardfp that spare me from compiling the most common packages?
Answer: As far as I can find out, there is no repository of pre-compiled packages for use with portage on Gentoo.
Your best bet would be to install the Raspberry Pi cross-toolchain on a more powerful machine and cross-compile the packages that you need.
You can find information about cross-compiling for the Raspberry Pi in this question.
Answer: Stage-3 for Raspberry 2 and Pi 3 optimised for the NEON hardware acceleration and the newer floating point unit 4. Compiling on the newer Raspberry 2/3, when using an external USB Hardrive is practical.
This page has links and all the important details, (6) Install Base System - (Stage 3 tarball).
Stage-4 is another story.
For the original Raspberry, you would need a Stage 3 ARMv6 binaries, but they would be pretty much identical to Raspbian. I could not recommend compiling on ARMv6 with limited memory its not very pragmatic.
You have to ask, why ?
If you want to run better, faster, binaries than ARMv6 because your hardware supports the new ARMv7 or ARMv8 and has hardware acceleration for audio and graphics - that makes sense. If you own the old original, the best answer is to simply buy a new board for $35.
To find out which cpu type in
cat /proc/cpuinfo
Comment: Good to know, thank you. Note however that this is armv**7**a, so it won't work on a Pi 1
Answer: It took some digging, but http://tinderbox.dev.gentoo.org/default-linux/arm/armv6j-hardfloat-linux-gnueabi/stable/ seems be the only source available, and it basically seems to provide only the stage3 binaries...
edit Now, there's http://gentoopi.technologysecure.com/


Using the quadratic formula.

Question: This may sound a bit basic but when using the quadratic formula working through $\sqrt{b^2- 4ac}$, should I be considering $- 4ac $ or $-(4ac) $? Not sure if this is worded correctly but some feedback would be helpful!
Comment: Either way, $-4ac=-(4ac)$.
Comment: no it is $$\sqrt{b^2-4ac}$$
Answer: Either way it would be correct, in fact they are the same. If you a have an equation of the form $$ax^2 + bx + c = 0$$ and want to find $x$ then, as the formula shows, you get $$x = \frac{-b \pm \sqrt{b^2 - 4 ac}}{2a}$$Note that all these constants $a,b,c$ must have their actual sign. For example, consider
$$ - 4x^2 + 2x + 3 = 0$$ then $$x = \frac{-2 \pm \sqrt{4 - 4\cdot(-4) \cdot3}}{2\cdot (-4)} = \frac{-2 \pm \sqrt{52}}{-8}$$
Comment: Im not sure what i did wrong on this problem that makes sense.  Think its time to sleep!  Thank you

Using the quadratic formula.


Custom Tab and Custom Object are same

Question: Can any one let me know is Custom Tab and Custom Object the same.If yes then in my EE i do get ab ERROR as : Custom Tab Limit Exceeded
Your organization's edition of salesforce.com has a limit of 25 custom tabs. To learn about options for increasing your organization's custom tab limits, please contact your account executive.Basically for custom object we can create upto 800.
Answer: Custom Tab and Custom Object are not same.
Custom object are custom database tables that allow you to store information unique to your organization.
While tab is one of the ways for provisioning users to access these objects for creation of data for salesforce object
Every object may not have tab while if you have a tab (Custom Object)  then it implies there is an underlying object.(Note tab can be a visualforce tab as well).
The reason you are getting this issue is your org has a limit that you can create only 10 tabs ,note that it does not imply you cannot create more than 10 objects .
Would recommend you to go through force.com fundamentals for more info on tabs,apps and objects
http://www.salesforce.com/us/developer/docs/fundamentals/
Answer:
Custom tabs are totally different from custom object and have different limits as well.
When you create a custom object you have an option by which you can create a custom tab for that object as well.
This custom tab will provide you a UI interface for your object records.
In EE you are provided 25 custom tabs.
You can ask salesforce to increase your custom tabs limit (paid)
In performance edition this limit is unlimited.
Answer: In Enterprise addition you can not create more that 25 tabs. Custom objects and Custom tab are different components.
You can not create more than 200 custom objects in EE edition. ( 800 ? )
Custom tabs provide user interaction with Custom objects while Custom object provides data storing structure.
Refer to: Custom Objects and Custom Tab
Comment: @Mohith Shrivastava,@sales_lion,@regal :Thanks for your reply.If i want to know what are the Custom Tabs ,Where can i find it?Can any one help me out with the navigation??
Comment: @nikkey I have given two links in answer. Did you get chance to open them?

Custom Tab and Custom Object are same


Does adding additional Powerline networking adapters improve overall performance?

Question: I am unable currently using 2 Powerline network adapters with mixed results. Was curious if adding additional adapters would improve overall performance. Thus far have been unable to find a clear answer.
Comment: Could you provide more details? When it works, what speed to the devices connect at? How far apart in the building are they located?
Comment: The adapters were working well enough for some time now. The connections are 2 floors apart. I have been using a Revue, PS3, Wii and a wireless router across them. About a week ago it stopped working on that electrical outlet.
Comment: I's even worse than that--additional adapters increase the probability of collisions.
Comment: The monster powernet 200 documentation claims you should add more adapters to improve overall performance. Whether this is really true or not I'd be interested in knowing in more detail.
Answer:
The monster powernet 200 documentation claims you should add more
  adapters to improve overall performance. I'm curious why they would
  state this if its clearly not true as the current answers state?

Their comment is quite subjective; if all of the powerline adapters were all electrically in the same location, then sure, adding more on the line would not only increase load, but add more noise filtering on the same line (hence creating a path of least resistance for the signal to travel over), thus adding more = a good thing.

Is it ever true? Is it just a gimmick to sell more units?

In your situation, I would say no; as your going across multiple floors.  Given that you are traversing across multiple circuits, the information has to travel the length of the powerline adapters down through the circuit breakers to the other adapter in the house. Thus, a longer path than simply between both units.

Is it true only for some brands/models? (ie the powernet 200 also does
  some noise filtering -- maybe more filtering is better?) Maybe more
  powernet units helps the units better learn the noise characteristics
  of your power?

This really would only apply if each unit were on the same line; not split across multiple circuits.  The current answer provides some additional detail as to why this would cause an issue; Houses with old wiring, for example, can interject so much noise on the line, or be ran improperly so much that increased attenuation on the line would cause the signal to degrade to the point where the powerline amplifiers couldn't properly pickup, amplify and filter out the noise.
Faulty wiring is another issue.  Even if the wiring in the house is brand new, faulty wiring, short circuits, exposed wires, even wires going around other junctions or around other pipes that can cause interference can add increased attenuation and signal degradation to the line.  Both of which the powerline adapter cannot fully compensate for.
So, the factors you have here are:

Faulty Wiring:  Injects noise and signal degradation
Old wiring:  Cause too much line attenuation to be useful
Separate circuits/long circuit pathways:  Causes increased signal attenuation on the line

And, lastly, you also have load:
When you add more units to the same line, you increase the load on the line; and as you increase the load on the line, you interject noise and attenuation; if it's on the same line, the attenuation can be compensated by the powerlines internal amplifier, but if it's on a separate line, it's like picking up a conversation in the next room, amplifying it, only to hear a muddy mess; unlike NCIS or CSI, these units cannot re filter out the signal and make the muddy mess into something clear enough to transmit to another unit.
Answer: I use a pair of 200mbs powerline adapters to connect with my office 150ft down the garden. Data speed for large file transfers is around 20mbps. If I plug in another adapter in the office (switched on but not used) the speed increases to 35mbps. Turning off or unplugging it results in the connection slowing down again.
In the past i have also connected other powerline adapters in the house - but these seemed to slow down or completely break the office connection, so i put in some cat5 cable to that device and then left it all alone for the last few years.
This seems very like dealing with the unpredictable behavior of radio signals - sometimes the best way of finding a solution is to just try a few things out until it works for you.
Answer: You can treat powerline networking for all practical purposes just like any other network, so unless you have some fancy networking kit that can aggregate bandwidth across multiple NICs and switch ports then adding extra powerline adapters will let you link additional computers, but not make a single link "go faster"
Answer: The underlying problem is most likely that the two devices are (electrically) too far apart, the wiring is old or unsuitable, or there is some form of interference. Adding other devices probably won't overcome this.
Answer: From Powerline FAQ :

What is line "noise"?
Every appliance on your electrical line generates noise, or
  interference, for Powerline transmission.  While distance has some
  affect on line noise, the number of appliances and age of electrical
  wiring will have greater impact.  The longer the distance and the
  greater the line noise, the less square footage you will be able to
  cover with Powerline.

It might be that some electrical appliance, new or old, is now generating electrical noise.
You could check if there is interference on one floor only or in the entire house,
by maybe turning off electrical appliances one-by-one or unplugging entire circuits
in the search for this appliance. This way you might create a map of problematic
appliances and/or electrical lines.


Why wouldn't debtors simply destroy their tally sticks?

Question: I understand that the distinctive way the two pieces of a tally stick and the markings on them fit together prevented altering records. But that system only works if you can bring the pieces of a tally stick back together. If you were in debt, and the only way a third party could verify that was with your half of a tally stick, why not just get rid of the thing and claim that you never borrowed from your creditor? You could keep a record somewhere else, but surely that defeats the purpose of the tally stick. You could be adversely affected by reputational damage in the long run, but again the tally stick isn't doing anything. Your reputation is inducing you to pay the debt.
Comment: **Comments have been [moved to chat](https://chat.stackexchange.com/rooms/148129/discussion-on-question-by-thomas-anton-why-wouldnt-debtors-simply-destroy-their); please do not continue the discussion here.** Before posting a comment below this one, please review the [purposes of comments](/help/privileges/comment). Comments that do not request clarification or suggest improvements usually belong as an [answer](/help/how-to-answer), on [meta], or in [chat]. Comments continuing discussion may be removed.
Answer: The tally stick is a document of a transaction just like any other. It doesn't 'do' anything any more than a land deed 'does' something or a modern credit card statement 'does' anything. It all depends on the trust given to the document by others. All documents depend on the collective faith in those documents, and the existence of agents (whether they be bailiffs, police officers, sheriffs, lawyers, whatever) who will enforce the claims made in the documents if need be. Somebody could conveniently lose their half of a tally stick, but the other party still had evidence that the loan took place, and could ask for redress.
Thus far the split tally stick was just a document like any other. However, the design of the split stick included inherent additional security to both parties over a simple 'receipt' or 'statement' in the modern style, because its design mitigated any attempt by the debtor to claim they owed a smaller amount, or the creditor to claim they loaned more than they actually did. In other words, the stick was in most important regards tamper-proof. That didn't take away the need for society at large to trust that the stick was not forged for some reason by both the parties, and it didn't prevent somebody trying to claim they had no knowledge of the loan. But in that latter case if a creditor held half a stick and was viewed as trustworthy by the local authorities, the person who denied the existence of their half of a stick was going to be on legally shaky ground, just as they would be if they denied the existence of any other document that was still in the possession of another person.
Edit
Further to MCW's comment, I did a little bit of searching for some examples of tally sticks being used as evidence of debts or payments. It doesn't exactly show an incidence of somebody denying a tally exists, but does show how the existence of a tally (or one side of tally in the hands of a debtor or creditor) was viewed and respected by authorities. The date of the law regarding sheriffs is not recorded in the Register of Malmesbury, but is before 1400.
Example of tally stick being used to seek redress of unpaid debt
(Acts of the Privy Council of England. Volume 42: 1627, January - August), p. 59. Extracted from https://sources.tannerritchie.com/browser.php?ipid=694108)

Law regarding illegal debt collections by sheriffs
Registrum Malmesburiense. The Register of Malmesbury Abbey, preserved in the Public Record Office. Volume I [Rolls Series]), p. 508. Extracted from https://sources.tannerritchie.com/browser.php?ipid=1356302
Comment: It's not my field, so I'm just reciting "received wisdom" so to speak, but it was such a widely used system in England alone that there must be a huge amount of case law out there on anything to do with tally sticks. Not a helpful answer I know, but I'm sure someone has done a bunch of research on it. It's also an incidence where a lack of evidence might be proof that the system worked, of course.
Comment: @MCW I've added a couple of examples I found after a quick search for how tallies were used in practice to show proof of a debt or payment. Not examples of somebody denying the existence of a debt, but (which is obviously much easier to find) the reverse.
Answer: @fred2's answer is a good one and I've upvoted it, but it's also worth remembering the societies in which these people lived and made their transactions. They were small, local societies where everyone knew everyone else. The fact of a transaction would usually be well-known and a matter of village gossip. Even in 19th century America -- where communication and movement was much, much greater and the local society larger than in a medieval or ancient society -- who owned what and who borrowed what from whom was one of the few topics possible for conversation.
"Well, Joe McGinnis's dad bought the land north of Hay Creek up to that hill top over there from Pete's grandfather maybe fifteen years ago -- remember, his barn burned down and he needed the cash to rebuild it? -- and Joe's dad had always wanted that hillside.  I heard that Joe's dad had to give Pete's grandfather three head of cattle as well as money."
The fact of a transaction would be well-known.  (It was very much in both parties' interest for the fact of a transaction to be well-known in a society which did not yet have a local Registry of Deeds, since for a property dispute to be settled in court, it would be done by examining any deeds and the memories of witnesses.)
The same applies to a lesser extent for any kind of transaction: The ability of a court to settle who owes what and who owns what relies on the memories and testimony of the community.
But while the fact of a transaction would be well-known, the details of subsequent payment would typically be less so, since they would be smaller transactions -- e.g., annual payments of a fraction of the amount owed -- and less interesting and less likely to be remembered. And there's where the tally sticks come in.
For Joe (or Pete) to destroy his one of the tally sticks would be futile, since everyone knew he'd had it and his family had bought the land and if he could not produce it, he would have to accept whatever the other claimed.
Your tally stick protected you from any unjust claims of the other party. There's no reason to destroy one.
Comment: @MCW Poorly, I'd imagine. Since over most of history "government" meant "armed thugs", the power asymmetry in pre-modern times was usually greater than today and most people had no means of resisting -- stories of Robin Hood not withstanding.  (There were few governments as enlightened as Imperial Rome's.)
Comment: At least from the Wikipedia page, these were usually used for tax records, not contracts.   Within the context of a contract, I agree (although the situation would actually be simpler, since reputation dominated facts), but given the power asymmetry, I wonder how things would play out if the Government destroyed the tally stick?  (There is no  plausible reason why the taxpayer would destroy the tally).
Answer: The modern equivalent of a tally stick would be the two copies of a contract kept by each side in the transaction: the point of having a copy is having the evidence that the transaction did happen and that the other side agreed to the terms stated in the contract.
Thus, destroying one's own copy copy forfeits the one's ability to prove that the transaction took place or to prove the one's claims regarding the conditions agreed upon. Obviously, having the evidence does not guarantee that one can enforce the contract - this requires external enforcement mechanisms, like courts, reputation, or public knowledge or simply good faith.
Comment: Agreed - I have been trounced in law by opposing parties who simply had more plausible evidence.  The court didn't bother to consider the facts of the case; the fact that my opponent's evidence appeared more credible was sufficient.   Having a half a tally stick would have  been a much more [colorable](https://en.wikipedia.org/wiki/Colorable). But this would be even more convincing if we had records of such challenges occurring
Answer: Another answer that relies on logic rather than evidence.
At least to my read of Wikipedia:TallyStick, tally sticks recorded partial payment of taxes.  (There is no need for an artifact to substantiate that you have paid none of your tax)
Destroying a record of partial payment would not benefit the taxpayer at all, and the government has other mechanisms to undermine the contract.
I'd be interested in records of court cases that covered challenges to tally stick contracts.
T. Anton points out that tally sticks have a longer history than the Wikipedia article indicates. I believe this to be true, but I don't have the time to support that belief with evidence.  (if I had better scholarship, it would require less time).
Comment: This was in the case of medieval England, but tally sticks have a far longer history, in which I do not believe they were usually related to tax


Dodging police bullet illegal?

Question: Would dodging, or otherwise itentionally avoiding, being shot by the police be considered resisting arrest? Mainly regarding U.S. law, but interested if any other law adresses this.
Comment: Are you talking about evading shots aimed in general at a crowd (i.e., during a riot or insurrection); or evading when one is the specific target of an arrest attempt, i.e. during a traffic stop? And when/if a weapon is shown by the person in question?
Comment: The latter one.
Comment: There was some Facebook clickbait going around about a police officer shooting at a man, missing, and killing another officer, with the man shot at charged for manslaughter, but I didn't follow that link, and now can't find any reference.
Answer: Prior to Tennessee v. Garner, 471 U.S. 1 (1985), common law allowed police to use deadly force to effect the arrest of a person suspected of a felony.  Even though SCOTUS there held that such a practice violates Fourth Amendment civil rights, I was surprised to find that in some states it is still lawful for police to use deadly force to effect an arrest!
Let us examine the most extreme case, which is that the police can legally shoot at you to effect your arrest.  As explained here, you are always allowed to resist "excessive force."  If you make it to court, these qualifications (e.g., "necessary" and "excessive") are ultimately decided based on what a "reasonable person" would have believed in the situation.  So if a cop shoots at you, and you "dodge" the bullet, it is possible for you both to be found not guilty of any crime.  I.e., the cop can be found to have acted "reasonably" because he believed you were a violent felon and shooting you was the only way to stop you.  And you can be found to have acted "reasonably" because you believed you were being subject to excessive force.
While this is an interesting hypothetical, in practice of course by the time a cop is shooting at you you are almost certainly going to be charged with resisting arrest.  Or, if the cop fired in self-defense (rather than to effect an arrest) you will be charged with a number of far more serious crimes (starting with felony assault, reckless endangerment, and going on from there...).
Comment: If SCOTUS has found a law unconstitutional, a state legislature not bothering to remove it or adding a new version later does not override the unconstitutionality - it's not lawful just because they ignore (the highest enforceable interpretation of) a supreme law saying it is not.
Comment: @Nij: so one would think.  See [the law review I linked](http://www.slu.edu/colleges/law/journal/police-use-of-deadly-force-state-statues-30-years-after-garner/): "Part III explains why, contrary to the belief of many, the decision in Garner did not require states to abandon the common law rule."  Highlight: "States may be required to strike down laws, but they can't be required to make them—or get rid of excuses or justifications they may have in the law.  States have to obey the Constitution, but they do not have to criminalize violations of the Constitution."
Comment: In what way is condoning violations of the Constitution not itself a violation?

Dodging police bullet illegal?


What are the visible differences of single-crystal and polycrystals?

Question: I saw a question where it supposes a particle of quartz sand with 1 mm in diameter is opaque white. I am then asked on whether this particle is single-crystal, or polycrystal. Admittedly, I am quite stumped here, as the things I've read up on these and heard in the lectures in the class does not go over anything regarding its visible characteristics, including color, size, and the like. I am aware that polycrystals consist of grains due to not having an ordered orientation like that of single crystals, and I am also aware that single crystals have flat surfaces in their geometry. However, I am not sure how these concepts would guide me to the correct answer, or if I am missing essential knowledge regarding how to differentiate them.
Answer: Quartz has a band gap of around 9 eV, which corresponds to light being in the UV. Therefore, any light with energies smaller than 9 eV cannot be absorbed by quartz. In other words, quartz should be transparent to any visible light.
Why would quartz ever be opaque in the visible spectrum then? Well, assume the sample is polycrystalline. Then when visible light enters the (poly)crystal (say, front the front), it refracts at various angles as it enters and exits the different grain boundaries. This means some of the light is bent away, and exits through different angles in the crystal. This makes the sample appear opaque.
Comment: Does this mean I can conclude that polycrystallines are typically opaque due to its grains?
Comment: Yes, if the single-crystal version of the material is transparent. If the material is metallic, so that all of the light is reflected rather than transmitted, a polycrystalline sample would probably just be less shiny.


Circuit to produce chattering relay

Question:
Here I have connected one coil terminal with arduino, which is giving 5V pulses and the movable contact to GND pin of arduino. I saw from literature that it is possible to get 1000-1200 v from a 12v DC relay. I don't understand from where we can measure the voltage and I need to know whether my method of making the relay chattering is correct or not. I need a detailed design for making chattering relay. I need to couple the EMI noise due to the chattering to a data cable. How can I do this?
Comment: ..........what?
Comment: Why? This is an X Y problem, detail the problem that you really need to solve.
Answer: If I undestand correctly, you want to use the relay coil to generate a high voltage by switching it very fast.
Currently your circuit looks something like this:

simulate this circuit – Schematic created using CircuitLab
As you can see in the circuit, the coil of the relay is active and will switch the output. Because the inductor tries to keep a current flowing, but because there's only a very high impedance connected to the output (Out), you will get a very high (negative) voltage on that pin.
Usually we don't want this effect and we put a reverse connected diode over the inductor of the relay (called flyback or kickback diode).
The circuit will start to oscillate by itself, because the coil is not getting any current, it will fall back to the NC position and then reactivate. Therefore I don't see why you put an arduino to it. First of all an arduino cannot supply the ammount of current needed to operate the coil of a relay and secondly it does not need to switch, you just need a fixed voltage on the input.
Lastly I would like to remind you that relays have a limited operating life, and when switching very fast it will not last very long.
Comment: This is a *great resource* on the topic, https://www.edn.com/unusual-emi-sources/

Circuit to produce chattering relay


Importance weight of conditioned particle in conditional SMC

Question: In a generic particle filter, I understand the importance weights for each particle are calculated as
$w_t^s \propto w_{t-1}^s \frac{p(y_t \mid z_t^s) p(z_t^s \mid z_{t-1}^s)}{q(z_t^s \mid z_{t-1}^s, y_t)}$.
I am confused about the weight of the conditioned particle in the conditional SMC (used in Particle Gibbs). Since the conditioned particle $z_t^N$ is set deterministically, does that mean that $q(z_t^N \mid z_{t-1}^N, y_t) = 1$?
Answer: Edit: I was mistaken. The particles in the path being conditioned on DO have weights. When you sample the $N-1$ ancestors at the beginning of each step, you may sample the conditioned-on particle as an ancestor. The weight formula here is roughly the same as the traditional formula you have written first.
To be more clear, the unnormalized weight for the $k$th particle, if $k\neq B_n$, at time $n>1$, assuming you just sampled the ancestor index $A_{n-1}^k$, is
$$
\frac{f_{\theta}(x_n^k \mid x_{n-1}^{A^k_{n-1}})g(y_n \mid x_n^{k})}{q_{\theta}(x_n^k \mid  y_n, x_{n-1}^{A_{n-1}^k}) }.
$$
For the special particle, where $k=B_n$, the ancestor is not random: it is $B_{n-1}$. So the above formula would change slightly to
$$
\frac{f_{\theta}(x_n^k \mid x_{n-1}^{B_{n-1}})g(y_n \mid x_n^{k})}{q_{\theta}(x_n^k \mid  y_n, x_{n-1}^{B_{n-1}}) }.
$$
I am using the notation from around page 10 of this paper, which describes the conditional SMC update. Sorry about the confusion earlier; I find it strange how they re-use the letter $k$ for the two different types of indices.
Comment: (-1) The weight of the conditioned particle is definitely used to sample indices: i)  the conditioned particle may obtain descendants (in addition to the conditioned one) in each resampling step  ii) in the end, the conditioned path may be selected as the "final result" of the cSMC step.
Comment: Thank you for your help. It is not yet clear to me that the conditioned particle has no weight. In the pseudocode you refer, I see that steps (a) and (b) (sampling ancestors and sampling new particles, respectively) are not carried out for the conditioned particle. However, in step (c) (calculating weights) there is no indication that the conditioned particle is left out.
Comment: @GonzaloBenegas there is an indication. The superscript is $k$, and $k$ is any index that does not equal $B_n$ at time $n$
Comment: I'm not sure $k$ does not include $B_n$ in step (c). If the conditional particle has no weight, how does it interact with the rest? What's the point of its inclusion?
Comment: @JuhoKokkala Thanks for the clarification. Regarding my original question, do you have any insights on how the weight of the conditioned particle is calculated?
Comment: @JuhoKokkala thanks for fixing my mistake. Figure 2 shows this nicely, too.


What is it like trading a CS:GO skin between two accounts?

Question: I got myself a knife in CS:GO but I have two accounts which I use both, if I were to trade my knife to my other account will I be able to use it instantly and trade it back when I'm done? Or is there some delay or limitations? Thanks in advance.
Comment: I believe that if both accounts have a steam authenticator associated with them, there should be no restrictions. It's been a while since I traded though, so I am not 100% sure.
Comment: Ok, I don't think my other account has Steam authentication. Is that the phone thing? Thanks for the reply!
Comment: That is the app on the phone where you have to confirm any trades. Accounts without authentication set up have a 14? day hold period where items are held in limbo, and the trade can be cancelled at any time.
Comment: Can't test it at the moment because I just got my knife and it has a trade lock, but thanks for the help. Hopefully it works.
Answer:
If I were to trade my knife to my other account will I be able to use it instantly and trade it back when I'm done?

Yes, you can trade it at any time. However...

Is there some delay or limitations?

If both accounts have an authenticator for at least seven days, and do not have any bans, then no.
If not, then yes as regardless of whether you own both accounts in a trade, all trades are considered as a "business" trade and thus is subject to standard trade restrictions:

If you have recently logged in to your account on a new machine, it will be unable to trade from that machine for 7 days. (Workaround: Complete the trade on a computer that is already established; more than 7 days since first login).
If you do not have a Steam authenticator attached to either accounts, it is subject to 15 days in escrow.
If one account does not have an authenticator, there is a 7 day escrow, unless... (See below)
If both accounts have been friends for at least a year, but one does not have an authenticator, there is a 3 day escrow.
If you do have a Steam authenticator attached on both accounts for more than 7 days, trades will go ahead instantly as soon as they're approved from the authenticator.
If either accounts have a VAC or Trade Ban, they will be unable to trade.

Note: Escrow times start from the moment all sides requiring an authenticator action are completed. (You know; go to Confirmations > [...] > Accept?)
Reminder: You can have MULTIPLE accounts use one singular authenticator.

This support page provides some information about Steam trading restrictions., though it's missing quite a few of the specifics.
Answer: If the accounts don't have a trade ban or cooldown and (if you have steam mobile authenticater) you can confirm that trade. You should have no problem!
Answer: There will be a delay unless you have Steam mobile authenticator on your other account. Sending your knife to your other account should be no problem, because your other account does not require Steam mobile authenticator to accept a trade where it's not losing any items. The only problem is if you want to send your knife back, you might have to wait two weeks (according to my friends who don't have Steam mobile authenticator and prime).
Comment: Prime doesn't have anything in common with the steam mobile authenticator
Answer: Set up the steam mobile authenticator for both accounts, then you can trade immediately between both of them.
 If you don't have the mobile authenticator activated on the account which trades an item away, you will have a delay of 15 days!
Note:

If you recently activated the mobile authenticator, you'll still have the delay for 7 days
You can use the same telephone number and mobile phone for multiple accounts to set up the authenticator
If you use the same telephone number on multiple accounts and one of your account is VAC banned ALL linked accounts get the VAC ban
Comment: Don't forget the 3 day to 24 hour delay if you've been friends for at least a year*.
Comment: http://store.steampowered.com/news/19618/ @Artery
Comment: @aytimothy Do you have a reference for this? Since when does this apply? Never encountered it.
Comment: @aytimothy Ah, thanks. Didn't know this, yet!