What's the name of these two surfaces?

Question:
I've plot two implicit surfaces which are shown in the above, I only know their expression, but I don't know how to call them.
Comment: *I only know their expression* - Well, we don't. $(-1)$
Comment: Topologically, the first is a 3-fold torus, and the second is a 5-fold torus. Geometrically, one cannot be more specific without knowing where you got these.
Comment: You said these two are implicit surfaces, is it defined by a level set of a function?
Comment: What does 3-fold and 5-fold torus mean?
Answer: The second one appears to belong to a family of surfaces defined by Banchoff based on the Chmutov surfaces of order $n$.  Explicitly, the implicit equation is given by $$3+8(x^4+y^4+z^4) = 8(x^2+y^2+z^2).$$  The first one is not known to me.  It appears to have a tetrahedral symmetry.
Comment: Yes,they are defined by a level set of a function

What's the name of these two surfaces?


Vote to Reopen an Optical Drive Question

Question: My Question I was wondering if this question can be voted to be reopened. I would like to hear any objections, with the reasoning of course. Since the tag requires reasoning. My reasoning is that the question has been added plenty of details. Any other details could be asked.
Comment: If you took some time to improve the formatting of your question.  You might have some users vote to reopen your question.  What software are you using to try to write the optical disk?  Instead of replying with a comment, you should edit and improve the question, replying with a comment won't result in anyone voting to reopen your question.
Comment: I was asking what software are you using to create the disk.  Windows has built-in support but not everyone uses it.  My request for more information is reasonable.  You suggesting I have no sense is extremely rude.  Your asking the community to vote to reopen your question. Your response to clarify your question and improve the format of your question is very reasonable.  I won't vote to reopen your question until your question has the required information to answer your question.  I will be honest, I have no idea what you mean by, "the sense becomes one with you." other than as an insult
Comment: @Ramhound No, my apologies I thought you were asking what files types I was trying to burn into the compact disk because it is not accepting anything. Other than that you are right, and I will verify that that clarification helps.
Answer:
would like to hear any objections, with the reasoning of course.

Your question lacks a great deal of formatting which makes it very difficult to read.  You have intentionally or unintentionally bolded specific words unnecessarily.    Bolding should be used sparingly.
If you disregard the fact your formatting needs to be improved, it's not clear what you are using to burn the data to the disk, and at what stage the writing fails at.  Since you are clearly running Windows, if you were using the built-in functionality, there would be two stages.  The first stage is preparing the disk session, this involves selecting if you want to keep the session or close it after the data is written.  Understanding what you have selected would help tremendously. The second stage would be after you have selected the option to finialize the disk.
You have also not selected what type of disk you are using.  Your drive only supports specific optical disks based on my research.  You must understand it supports more than a  half dozen different types of optical disks, and you wouldn't be the first person, to refer to an optical disk as a "CD-ROM disk".  So understanding what type of disk you are using would help tremendously.
I might actually be overthinking your problem, if you cannot even access your disk to initialize the session, that would change the premise of your question entirely.  It would, of course, raise the question if the drive ever worked in the device.  It would also be helpful to know if the device is properly recognized in Device Manager.

Any other details could be asked.

Some of the details I am pointing out, specifically the type of disk you are using, shouldn't be things we have to ask for you to provide.  Even if we do have to ask for them, you have used incredibly vague words like "CD", believe it or not, "CD" isn't a very good description.
You don't actually specify in any great detail the reason the existing question doesn't answer your question.  You really only indicate it did not resolve your problem but offered no details.  Your question could easily be improved so it could be reopened.
Comment: My apologies for yesterday it's just I have come across many insensitive remarks when it comes from users. I am honestly trying to learn and troubleshoot much myself, I am at the beginner's level when it comes to this. I appreciate your help and time.


"Lebesgue measure" or "the Lebesgue measure" - omitting the definite article or not?

Question: I noticed that many people sometimes omit the definite article before "Lebesgue measure". Some examples: "suppose that m is Lebesgue measure on R, "we will construct Lebesgue measure on R", etc. This looks odd to me and in both cases I would have written "the Lebesgue measure" and I see that, for instance, this is how Rudin expresses himself in his classic text (at least in some places, he seems to use both of these variants).
My question is whether the article should be omitted here or whether it is a matter of personal taste.
Comment: I wouldn't say it's "all right", no (it's *never* correct to drop the article before a noun phrase like this). So don't bother trying to learn some obscure principle whereby *sometimes* it might be "more excusable" to omit the article. Just do it the *right* way yourself every time, and don't take any notice of others (native Anglophones or not) who get it wrong.
Comment: @FumbleFingers I agree with you, thank you very much for taking the time to look into this.
Comment: I think the article would be usual.
Comment: @mdewey thanks, but then why do so many authors omit it? I guess that both are correct, but the article feels more natural.
Comment: I did a bit of searching to see *where* the article-less form occurs. Typical seems to be this: [***The** collection M is **the** Lebesgue σ-algebra of R, and **m is Lebesgue measure** on R. **The** elements of M are known as **the** Lebesgue measurable sets in R.*](https://www.google.com/search?tbm=bks&q=%22m+is+lebesgue+measure%22) When there are that many articles kicking ariound in the vicinity, it's forgivable to discard one now and then! I also get the impression a ***lot*** of the relevant "science-based" writers aren't native Anglophones anyway.
Comment: @FumbleFingers I see, so if we want to be rigorous we should stick to "m is the Lebesgue measure on R", but in cases where there are many articles one after the other it is all right to omit some of them, right?
Answer: Assuming there is only one Lebesgue measure, the "the Lebesgue measure" would be correct, and you should not drop the definite article.
If there are many different measures then you could say "a Lebesgue measure".
In either case you shouldn't omit the article, as the mathematical sense of "measure" is countable.
Comment: thank you very much! There is indeed only one Lebesgue measure and this is a well known result in maths. I am really glad that people also answer such technical questions here, it is a bit difficult for a non-native to learn technical vocabulary and wording, lucky for me there are such great forums nowadays!


2 Pin Flame Sensor

Question: I recently found a 2 Pin flame sensor. It looks just like an LED except it's black. It is not a module and I couldn't find any wiring tutorials for these, just for modules. Does anyone know how to wire this? Also, why would it be wired so? Thank you
Comment: If this is Arduino specific, maybe it belongs over on Arduino SE. Also, you probably need to supply more details, like a datasheet or something.
Comment: You've got to at least provide a picture or something. "2 Pin flame sensor" isn't much to go on.
Comment: Sorry for not adding a photo. It is there now. Thank you
Comment: My best guess is that this is an IR photo-transistor or IR photo-diode.  It **IS** possible that it also includes signal conditioning but, based on the shape, I think that is highly unlikely.
Comment: I received one of these among many other parts in an Arduino Uno learning kit,. I knew it was a flame sensor but it was very hard to find information about it, until I knew it's probably a YG100.
Answer: This is probably a YG1006 flame sensor.
I found this in another kit's description: "The Flame sensor is a high-speed and highly sensitive NPN silicon photo transistor based on the YG1006. It can be used to detect fire or other wavelength at 760nm ~ 1100nm light. Response time is 15us, supply voltage is 3.3-5V; output is analog."
Comment: "Due to  its  black  epoxy  the  device  is sensitive to infrared radiation". Loses something in the translation.
Answer: This looks like the IR photo-transistor used in the common Arduino flame detector modules. Explained here and here.
Here is how it works. The photo-transistor starts conducting when it gets IR light from a flame or any source strong enough. A comparator can be used to convert it to a digital output. The second link above has a schematic that the Arduino modules use.
That being said, this could also be a photo diode since I couldn't find any official specification on this component. The working principle would be similar but the wiring would be different. Basically you could wire this like any other photo diode or transistor. I would wire it in different ways and measure the changes in current/voltage when pointing to a flame. You could start with the schematic below and use a multi-meter to measure the output voltage.

simulate this circuit – Schematic created using CircuitLab

2 Pin Flame Sensor


Which vacuum do I use for the path-integral?

Question: In Weinberg, vol. 1, Section 9.2, Weinberg defines the in and out vacua as states with no particles (9.2.4):
$$a_{\rm in}|{\rm VAC,in}\rangle=0$$
$$a_{\rm out}|{\rm VAC,out}\rangle=0$$
 He does this by assuming that the Heisenberg field operators $\Phi(\vec{x},t)$ are asymptotic to the interaction-picture, free-field operators, because they can be expanded as plane waves with free-field dispersion relations (9.2.5):
$$\Phi \to \int_p [a_p \exp(-i \omega_p t + i p\cdot x) + h.c. ]$$
This means that the asymptotic vacua are eigenstates of the free hamiltonian,
$$H_0=\sum_p \omega_p a^\dagger_p a_p\,,$$
correct?  But I thought that the path-integral corresponded to expectation values of time-ordered products in the full, interacting vacuum, i.e. in eigenstates of $H$. Moreover, if they are eigenstates of the asymptotic $H_0$ hamiltonian, how do we know that the in and out vacua are the same state? What happened to
$$ \langle T\{ \mathcal{O}(t)\mathcal{O}(t')\}\rangle = \frac{\delta^2}{\delta J^2}({\rm path\, integral}[J])_{J=0}\quad?$$
Comment: The key point is that interaction can not transform vacuum, evolution of vacuum state under perturbation gives nothing more than phase factor
Comment: @ArtemAlexandrov That seems to contradict the arguments above.
Comment: I don't have a copy of Weinberg's textbook on me, but I'm pretty sure he mentions that the in and out vacuum is the same thing somewhere.
Answer: The 'in' and 'out' states, as Weinberg defined in Chapter 3, are eigenstates of the full Hamiltonian $H$, not the free Hamiltonian $H_0$.
$a_{\text{in}}$ and $a_{\text{out}}$ are the annihilation operators for the 'in' and 'out' states, respectively. They are not free-field operators. Any proof of the LSZ formalism would involve constructing such operators, if you want more detail or an alternative view.
Eqn. (9.2.5) simply claims that the limit of the Heisenberg field at $t\rightarrow \mp \infty$ can be expanded in terms of creation and annihilation operators at that time. You are free to do that at any given time, just that the operator won't be time-independent like with free fields.
Comment: But why should the Heisenberg operator have a well-defined limit as $t\to \pm \infty$?
Answer: As answered by JF132, the 'in' and 'out' states are eigenstates of the full Hamiltonian, and the $a_{\rm in}$ and $a_{\rm out}$ are not free-field operators.
The limit that Weinberg is using is known as the 'weak topology' limit. That means that the matrix element of the operator between normalizable states will have this limit. Intuitively, this is because a normalizable state always asymptotes to well-separated wave packets that are effectively 'free' from each other (cf. Haag: Local Quantum Physics, or https://en.wikipedia.org/wiki/LSZ_reduction_formula)
The above proof of course assumes that there are no massless particles. If there are, then the states will not really be asymptotically free and the operator cannot be so decomposed. This somehow shows up as infrared divergences when the usual formulae are used.


Confused with the alias solution?

Question: I am trying to define alias for a group of commands counting recursively and displaying the number of all sub-directories encountered for any working directory (including ones with invisible file names). So far what I have done is:
ls -R | wc -l

But it does not display the hidden files number. So I tried this command:
ls -l | grep ^d | wc -l

But I am not sure whether it is the right command or not?
Answer: You should never parse the output of ls. See some explanations here:

Why you shouldn't parse the output of ls(1)

As others recommended, use find instead. And the best way (even when you have directory names  that contain  newlines  or other  types of white space) would be:
alias countdir='find . -type d -print0 | tr -dc "\\0" | wc -c'

See man find, man tr, man wc for more info.
Answer: Is find . -type d|wc -l a solution?
Answer: I'd recommend using find (man page) to do the searching. As an example,
find . -maxdepth 1 -type d | wc -l
will print the number of all directories in the current working directory.
The -maxdepth option controls how far find will descend into the directories. With a value of 1, it will just use the current directory and list its subdirectories. With 2, it will list the subdirectories' subdirectories, too, and so on.
This has just a single, small drawback: find includes . (the current working directory) in its listing, thus the number returned by wc -l will be off by one.

Confused with the alias solution?


Generating a web site from xsn files

Question: As we all know, the infopath forms service residing on a sharepoint server generates a web site each time we publish an inforpath form template to the sharepoint server.
Here is the question: how does sharepoint do that. Is there any way for us to do that programmatically via some kind of api provided by MS?
In fact, what I need to do is getting all the html, js, css etc. files and applying some kind of operations like deleting some divs or insert some html code into the particular web page. I have come up with two ways to do this.

Generating the web page via sharepoint api and apply those operations at the same time
Extracting the web page files from the IIS server and apply those operations

I am totally new to this kind of work. All in my mind is that each time we right click on a web page in the browser and choose to save the web page, the browser gets some of the files we need to render the web page and makes it possible for us to browse the web page offline.
httrack
WinWSD
and tools like that seems to work fine with extracting html files from online web pages but not that well with js, css files.
Now I am trying to dig into the chromium project for some kind of inspiration, although whether it helps or not is unpredictable.
Any kind of advice will be appreciated.
Best Regards,
Jordan
Answer: Infopath xsn files are just zip files with a different extension.  you can rename the extension to .zip and extract out the files.  you will find a number of files that make up the form.  the two main ones are the .xml and .xsl files.  the .xsl will have the html to generate when applied to the xml.

Generating a web site from xsn files


Can current and resistance result in establishing voltage?

Question: I want to know whether current & resistance can cause a voltage across the circuit, according to Ohm's Law $V=IR$. Is it possible to use a low current to produce a high voltage?! How can this be, as current is directly proportional to voltage?
Comment: Please try to improve your formulation first and take the time to add more details if you expect an answer.
Comment: Related: http://physics.stackexchange.com/q/51875/2451
Answer: Ohm's law can be summarized as this: The drop in electric potential (voltage) across a section of a circuit is equal to the total current flowing through that section of the circuit multiplied by the total resistance of the section of the circuit.
By that law, if you have a current flowing and there is some net resistance, there will be a drop in voltage.
The equation from Ohm's Law is $$V=IR\quad\text{or}\quad(Voltage)=(Current)\times(Resistance)$$
Based on this, it is certainly possible to have a very low current and a very high voltage. Remember, current is only directly proportional to voltage if the resistance stays constant. If resistance changes, then current does not need to change proportional to the voltage drop. Also, for example, if you have a large resistance (say 10 trillion Ohms), you can have a potential of 1 billion volts and your current would still only be 0.1mA (a very low current)
Comment: Yes you can but ill require more than a simple resistance and dependeds if its AC or DC. tip: search for solenoids. Btw all fluorecents lamps uses a reactor to generate high voltage/low current since gases only ionizes at high voltages
Comment: Just adding. For a pratical experiment OP ill need to keep the current constant and increase the resistance to observe the increase in voltage and that implies in some pratical problems. At the other hand he can observe that in any fluorescent lamp or at his car eletric starter system =)
Answer: For a constant resistance Ohm's Law is $$V = IR.$$
Now, it happens that it's pretty easy to make a constant-resistance device (we call them "resistors") and that it's easier to make constant-voltage devices than constant-current devices. So most of the circuit problems we encounter have a constant-voltage device like "a wall socket" or "a battery" or "a regulated power supply" driving currents through some loads.
The reason for this is probably that a device with a constant voltage across its elements can still has that same voltage when it's removed from the circuit: if I have a 1.5 V battery, its potential is 1.5 V whether it's running my flashlight or sitting in my closet. A true constant-current device, on the other hand, would quickly build up a big charge on its terminals if you didn't provide some return path.
However, there's nothing special about voltage that makes it more fundamental than current, and there are several types of devices which can be thought of as "current sources." The most common is a bipolar junction transistor, a three-terminal device, when connected to an appropriate power supply network. If a small current $I$ flows into a transistor's "base", a much larger current $hI$ (with $h$ typically 200–300) will flow from the transistor's "collector" to its "emitter." Depending on the resistances between the power supply, the transistor, and ground, the transistor current may drive the voltage at the collector/emitter terminals to just about any value. (In digital logic, the transistors are usually driven "to saturation," so that the voltages are either near the supply voltage or near ground — effectively the transistor acts like a switch. And in real analog circuits, one uses transistor networks, since the gain $h$ is not a stable, reliable parameter for a single transistor.)
An even better approximation for a constant-current device is a photodiode. In the photoelectric effect, one absorbed photon causes the emission of one electron; when the device is under more light, it produces more current. A photodiode with no current return path essentially charges itself up like a capacitor until the voltage at the junction is the same as the work function for the cathode; a photodiode whose terminals are connected by a resistor will have an output voltage $V=IR$, where $I$ is the photocurrent.
If the photodiode is powered, as in a vacuum photodiode or a photomultiplier, the output voltage can be quite large — or more frequently, a tiny photocurrent can produce a measurable voltage signal.
Answer: Let's get this straight, current flow in a conductor is a direct result of a voltage applied across it (a potential difference or electric field pushing the electrons through the wire), and no conductor has zero resistance (apart from a superconductor).
The current is a result of the voltage, not the other way around.
You can have a large voltage across the conductor with low current if the resistance is high. According to Kirchoff's loop law, the electric potential energy provided to the electrons must be dissipated by the circuit. Assuming the voltage is held constant, if the resistance is high, the current must reduce to compensate and hold V=IR true. This is how you can have a high voltage with a low current.
If you need any further clarification, leave a comment, however, I sense that if you revisit a few concepts this should become clear to you.


Algebraically closed field extension can be not algebraic?

Question: By definition, one says that an algebraic closure $K$ of a given field $F$ is an algebraic extension of $F$ who is algebraically closed. This makes me curious about whether there exists an extension $K'$ of $F$ who is algebraically closed, while $K'$ is not an algebraic extension?
Comment: When you say $K'$ is not an algebraic extension, you need to qualify that. Specifically, $K'$ is not an algebraic extension of _what_ field?
Comment: @quasi, I am talking about extension of the field $F$.
Answer: Sure, this occurs naturally. Consider $F = \mathbb Q$ and its algebraic closure $K = \bar{\mathbb Q}$. Now consider $\mathbb Q$ as a subfield of $K' = \mathbb C$.
$\mathbb C$ is algebraically closed, its an extension of $\mathbb Q$ but it is not algebraic over $\mathbb Q$.

edit: Here is another example. Let $F$ be a finite field and let $K$ be its algebraic closure. Let $F \subseteq F'$ be an extension of $F$ of sufficiently large cardinality (i.e. uncountable) and let $K'$ be the algebraic closure of $F'$. (*)
$K'$ is a field extension of $F$ that is algebraically closed but it cannot be algebraic over $F$ because its cardinality is too large. I.e. there are only countable many polynomial roots over $F[X]$ but $K'$ contains uncountably many elements - most of which cannot be algebraic over $F$. In this fashion you can get an arbitrarily large 'gap' between the cardinality of the algebraic closure of $F$ and an algebraically closed extension. (The fact that $F$ is finite is irrelevant here - I simply thought it might help to make this example more approachable.)
(*) Note that $F'$ exists by the existence of the infinite field $K$ and the upward Löwenheim-Skolem Theorem, but you can also just view it as a field extension $F' = F(x_i \mid i \in I)$ with indepenent $x_i$ and $I$ uncountable.
Comment: Sounds very easy, I should have thought about this by myself..
Comment: I liked your question - even though the answer may seem trivial in hindsight. Coming up with (counter-)examples while learning something new is always tough...
Comment: Maybe I can conclude that if I want to construct an algebraically closed extension $K$ of a field $F$ which is not algebraic then $K$ must be an extension of one of the algebraic closures of $F$? So in order to obtain such an extension we need to first construct an algebraic closure, then extend it by adjoining a transcendental element:)
Comment: Yes, that's right. The algebraic closure of a given field is - up to isomorphism - the $\subseteq$-least algebraically closed field extension of said field. So any other algebraically closed extension must contain some such (or - depending on your point of view - *the* up to isomorphism unique) algebraic closure.
Answer: Let $K'$ be an algebraic closure of $F(x)$, where $F(x)$ is the field of rational functions over $F$. Then $K'$ is an extension of $F$, and is algebraically closed, but is not an algebraic extension of $F$.
Answer: Sure.  $\mathbb{C}$ contains $\pi$.
Let $F = \mathbb{Q}$.  $\mathbb{C}$ is algebraicly closed (although it is not the algebraic closure of $\mathbb{Q}$, which is just the set of algebraic numbers) and is an extension of $\mathbb{Q}$.  But $\mathbb{C}$ contains $\pi$, which is not algebraic over $\mathbb{Q}$, so $\mathbb{C}$ is an algebraically closed transcendental extension of $\mathbb{Q}$.


Prevent an item from updating while approval workflow in process and once completed

Question: I have a calendar list in SharePoint 2010 where I have a SharePoint designer workflow for approving vacation request. Approval workflow is working fine and there is also an event receiver when an item is deleted that sends email to requester and approver. I want to Prevent an item ( event) from updating while approval workflow in process and once completed. I want to see the below screenshot and show error msg to user that says which is highlighted in the edit form
Answer: Maybe try this. Add a Rule in the Form Open Event to check the Workflow Status.  If it is set to In Progress (2) then set the form (a New View) to ReadOnly View.  Here is a breakdown of the Values (Whatever you name the Workflow, becomes a Metadata Column in the list. That is what you check for)
Status  Value
Not Started 0
Failed on Start 1
In Progress 2
Error Occurred  3
Canceled    4
Completed   5
Failed on Start (retrying)  6
Error Occurred (retrying)   7
Canceled    15
Approved    16
Rejected    17


Why is the 5th book of the Bible called Deuteronomy?

Question: Given that the meaning of the Greek word "deuteronomos" is 'secondary' it is expected that the name should be given to the 2nd book rather than the 5th: so why is the 5th book of the Bible called Deuteronomy?
Answer: The English "Deuteronomy" is derived from the book's name in the Septuagint: "Deuteronomion", meaning "Second Law".
The Hebrew name for the book is "Devarim", or "[the] words", the book's opening words.
The introduction found in the Oxford Jewish Study Bible explains the origin of the Greek name:

That approach to naming the book represents the Greek translation of the Hebrew phrase "Mishneh Torah" found in Deuteronomy's Law of the King, where it refers to "a copy of the law" (17.18 n.). That phrase was understood in ancient rabbinic sources as a reference to the book of Deuteronomy itself (Sifre §160), understood as a "second law" or "repetition of the law," because of the extent to which Moses, throughout the book, revisits the earlier laws and narratives of the Tetrateuch (the first four books of the Bible) and teaches Israel about them (see Naḥmanides on Deut. 1.1 and Ibn Ezra on Deut. 1.5).
Comment: Mishneh Torah is also the oldest Hebrew name for Deuteronomy. The Hebrew name "Devarim" or "Elle Haddevarim" as a reference to the book didn't exist until the Middle Ages as far as I know
Answer: As has been pointed out it is named Deuteronomy because this combines two Greek words δεύτερος (deuteros) which means second and νόμος (nomos) which means law.  It was given the title of the second giving of the law.
The reason for its placement last in the Torah is due to the fact that it came at the end of the 40 years of wandering in the wilderness after Israel sinned at Kadesh Barnea.  That means that the Torah has a loose chronological basis. The events of Genesis coming first.  The events of Exodus coming second, with Numbers and Leviticus coming in the early days after having left Egypt. Then nearly forty years later Deuteronomy since the original generation had all died except for Joshua and Caleb.
This of course depends on the belief that Moses wrote the entirety of the Torah except for the small portion at the end of Deuteronomy that records his death (most likely Joshua added that part to the Mosaic content). I reject the notions of source criticism that attempts to suggest multiple authors and that the Torah was not finalized until after the captivity. That false theory is known as the Graf-Wellhausen theory as put forth in the middle of the nineteenth century.
Answer: The simple answer is that- the laws that were already given once, while the Israelites were in the wilderness, by God are being repeated a second time just before they cross over the river Jordan as a reminder to keep God's commandments.
It's a retelling, a second giving of God's law, hence the name. It's also the reason you'll find the 10 commandments once in exodus and again in Deuteronomy.
Answer: All Pentateuch books got their name from the first verse, and in Hebrew this book call "Dvarim" (literally "things, what one has to say").
The sages of the Mishna and the Talmud refer to this book as "second things" (took it from verse 18 ch 17) and this is the idea beyond the name that the Septuagint uses: Deuteronomion - Second Law.


Another meaning of wollen

Question: I've come across the verb wollen (always in the 3rd person, I think) used not as 'to want' but more like the english will. For example, Angela Merkel "will dort mit dem französischen Präsidenten Hollande und den Staatschefs aus Russland und der Ukraine zusammenkommen." I don't think the willingness of Merkel to meet them is in any way implied, so it should be translatd as that she "will meet there with the french president.." If so, in which cases more specifically are we allowed to use it like that?
Answer: No, it still means to want in that case.  German will is a false friend, and English will just happens to be a good translation in this context.
Perhaps the confusion lies in the fact that in German future tense need not be so explicitly marked as in English, and present progressive is not a tense at all.  You could alternatively translate it as Merkel plans to....
The major case where wollen takes on another meaning is in such sentences: «Sie will es nicht gesehen haben.». (Incidentally, werden is also overloaded in such cases: «Sie wird es nicht gesehen haben.» expresses probability.)
However, the future tense in Yiddish is expressed with the cognate of wollen, like in English, as you suggest, so that's strong evidence that it was similar in at least some dialects of German in the past.
Comment: The English "will" is not a good translation in this context. "Wollen" implies a wish or intention, better translated with "wants", or possibly "intends" or "plans"
Comment: Sure, it's not 1:1.  If it occurred organically in the target language to describe this scenario - which is generally the goal of the highest quality translations - nobody would think anything of it.  If you condition too much on the source text, you get "translationese".
Answer: German »sie will« is »she wants« in English. It is NOT »she will«!
English »she will« is »sie wird« in German.
correct and wrong translation:

Angela Merkel will den französischen Präsidenten Hollande treffen.

is in english:

correct: Angela Merkel wants to meet the french president Hollande.

It is not:

wrong: Angela Merkel will meet the french president Hollande.

Explanation:

Angela Merkel will den französischen Präsidenten Hollande treffen.

This means:
Angela Merkel has now the plan to meet Hollande. But maybe Hollande doesn't want to meet Merkel. So now Mrs. Merkel has the plan to meet Hollande, but it is unclear, if they really will meet. Now Merkel is willing to meet him.
The grammar tense of this sentence is: Present tense. The sentence's core is: Merkel has now the wish to meet Hollande.

Angela Merkel wird den französischen Präsidenten Hollande treffen.

This means:
It is absolutely sure that Merkel will meet Hollande in the future. Hollande knows that Merkel wants meet him, he agrees with the meeting, and now they have an appointment. It is unlikely that this meeting could be canceled, so you can take it as an fact, that Merkel will meet Hollande in the future.
The grammar tense of this sentence is: Future tense. The sentence's core is: Merkel and Hollande have an appointment in the future.
Answer: You are probably correct in as far as the German "will" expresses here more an intention than a wish, but the English "will" would be understood as implying neither and would therefore be a bad translation. This example does however show how the English word could become an auxiliary verb.

Another meaning of wollen


Why is $\alpha$, a primitive pth root of unity, a root of the polynomial $1+t+\ldots +t^{p-1}$?

Question: I'm currently reading a proof that the minimal polynomial of $\alpha$, a primitive pth root of unity, over $\mathbb{Q}$ is $$1+t+\ldots +t^{p-1},$$ yet the author simply states "Clearly $\alpha$ is a zero." in the proof, and I can't seem to prove that bit myself.
Comment: Oh, now I see that if I multiply the polynomial by $(t-1)$ I get $t^p-1$, which zeroes are clearly $1, \alpha , \ldots , \alpha ^{p-1}$.
Answer: Note $(1+t+\cdots + t^{p-1} ) (1-t)= t^p -1$, and that $\alpha$ is a root of $t^p -1$, since it is a pth root of unity, but not of $1-t$, since it is primitive. Then it must be a root of $1+\cdots+t^{p-1}$, as the author says.


How do I remove this particular rear cassette?

Question: I'm having a hard time trying to remove this cassette; sheer force isn't working well, nor leverage, here are some photos:

The rear wheel is off an old road bike.
Comment: Welcome, I suggest taking the Welcome [tour]. Can't you make the photos smaller? If the external link becomes dead, the question loses its context.
Answer:
Secure tool in sturdy bolted-down bench vise.  The flats should be in the jaws, with the splines pointing upward.

Lower your wheel onto the tool so the splines engage.

Unscrew (counter-clockwise) wheel from freewheel (yours is not a cassette!). Can take some heaving.  You will have more grip and leverage if the tyre is installed and inflated.
Answer: It seems like a Freewheel, not a cassette.
If you do not have a vise, as suggested in JoeK's answer, my suggestion is to strap the rim as firmly as possible to a heavy bench or other solid object, so you can apply greater force with both hands to the wrench.
If the tool slips out, use a quick release skewer or the axle with a nut to hold the tool in place
I see you have the tool necessary to remove the freewheel, but I'll suggest this method anyway, as it makes easier to apply penetrant oil to the threaded interface between the hub and the freewheel core.
I've had to remove stuck freewheels without having all the proper equipment, what I did was to disassemble the free wheel while still in the hub, leaving only the core piece attached, which later was tightly clamped on a medium size vise attached to a heavy workbench, at which point I could use the whole rim for leverage.
Disassemble the freeweel
To disassemble a freewheel, first unscrew the lockring that sits inside the smaller cog. In your photo there are little dimples at 11 and 5 clock position. Those are for a tool that engages this lockring. I did not have the tool, so I used a blunt nail and a hammer. Put the nail tip sideways in one dimple and hit it with the hammer, trying to rotate it counter clock wise (I mean, the nail is not placed straight downward, but in oblique position). Alternate between the two dimples. A few firm hammer blows should be sufficient to loosen the lock ring. Once you unscrew completely this ring, you will see the outer ball bearing balls (there is another "inner" set bellow, closer to the hub body).
Then put a plush towel under the hub and lift the cogs. The bearing balls could cascade if they are dry and loose, that's what the towel is for. The pawls of the ratcheting mechanism should remain attached by a semi-circular spring around them. Remove them carefully.
If you plan to re-use the freewheel, use soft jaws on the vise or wooden blocks and be sure to clamp the core not touching the bearing races.
Of course, this method was ok for me on times where a full cleanup and re-lube where in order too, or the freewheel was to be tossed out and replaced with a new one. as it requires much more time. To reassemble the freewheel I use a thin layer of thick grease to stick the balls in place.
I also had to resort tho this method once in spite of having the correct tool, as there was no practical way for me to apply enough torque the the wrench. (Cheap tools, worn splines. The tool kept sliding off position). That time a heavy pipe wrench as used to destructively remove the core.
DIY tool for removing the freeweel lock ring
A bike mechanic friend of mine makes his own tools for these kind of lockrings by drilling tho holes in one end of a flat mild steel bar. The hole centers must be apart by the same distance as the dimple centers. He then places a bolt through each hole and secures it with nuts, so both bolts protrude to the same side. The bolts had the ends shaped with a grinder so they have a small rounded tip that engages the dimples (or otherwise the appropriate shape for the task). The other end of the flat bar can be wrapped with handlebar tape or inner tube strips.
In his case, that made sense as he needed some different sizes, and while the tool itself is cheap, could be not available in the correct size or the shipping cost to our country easily outweighs the time and effort he puts into making them himself (plus he gets to brag about it)
Answer: I don't think you have the right tool to remove the locking ring. I think you might need a SunRace Freewheel Lockring Tool, but on second thought, that doesn't look right either. Like Jahaziel says, make your own.
Comment: The two dimples visible on the lockring are for disassembling the freewheel mechanism, and will not get the whole unit off the wheel.  They can be ignored for the purpose of removing the freewheel+cogs from the hub.
Answer: Several times it happened to me that I had to vigorously step on the lever which was connected to the sprocket tool. Hold the wheel firmly and step on the lever with as much force as possible. Be careful and observe the objects in the likely continuation of the movement of your leg. Be careful to not injure yourself by the sprocket teeth. Some initial positions (angles) will work better than other ones.
If you just end up stendimg on the lever after you have jumped on it, for a moment, you really need a bigger lever. Get some solid metal tube and put it on your existing lever.


Seeking a particular problem

Question: I recall seeing a problem in Games magazine, probably in the early 1990s, that required the solver to deduce that a capture en passant was possible (not just because that's the only way to get a solution, but using retrograde analysis). I recall that all the pieces (including pawns) on the board were congregated in one corner — if I recall correctly they were all in the first three files and the last four ranks. The solver was required to mate in a small number of moves, possibly two. Does anyone know what problem it is?
Answer: I found a problem that perfectly fits your description! I've played the position back a move for the double step.
<code>[Title "Kurt Keller, Stuttgarter Nachrichten & Südwest Presse (Ulm) 1993, Mate In Three"]
[FEN "5RbN/5ppk/5P1P/5P1K/8/8/8/8 b - - 0 1"]
[startply "1"]
[startflipped ""]

1... g5 {Now White mates in three.} 2. fxg6+! fxg6+ (2... Kxh8 3. gxf7 Kh7 4. fxg8=Q#) 3. Nxg6 Bf7 4. Rh8#
</code>
If the Games magazine flipped the position, then this is a problem with all pieces in one corner, on the first three files and last four ranks, a short number of moves, and an en passant key! Even if it wasn't flipped, your mind might have altered your memory. Since the problem itself is from the early 1990s, it's safe to assume that the Games magazine reprinted it for show.
Addendum 7/2/2022: I came across a mate in two by Pal Benko that also fits the fill perfectly. (Once again, I've played it a move back so the replayer works properly.)
<code>[Title "Pal Benko, 1996?, Mate In Two"]
[FEN "kbN5/npp5/B1N5/P1K5/8/8/8/8 b - - 0 1"]
[startply "1"]
[startflipped ""]

1... b5 {Now White mates in two.} 2. axb6! cxb6+ 3. Nxb6# (2... Nxc6 3. b7#)
</code>
While the YACPDB database actually lists the source as "Games", the Die Schwalbe Chess Problem Datase sheds series doubt that on that publication date/source.
To quote it, translated from German:" In 'My Life' [,by Paul Benko,] the original source is "Games 1996" - it is unclear which publication is meant. The name Benko does not appear in the index files of the 'Games and Puzzle Journal' [Jelliss], according to 'Chess Periodicals' [Felice] there were some magazines that could fit the name (see p.90ff, entries 1016ff), but their publication period ends well before 1990."
The Games and Puzzles Journal archive is here: http://www.mayhematics.com/p/p.htm I found it not in any 1996 issue. Either it is in another issue, with a wrong date given, Benko forget the source to his own problem, another unknown source named "Games" is meant, or one of many strange possibilities is the answer to this problem's origins.
Answer: If it's from a source like Games Magazine, which does not have
a regular chess column, then I guess the problem was not a first publication
but a reprint of this Amelung classic, which fits the description almost
perfectly up to reflection (and perhaps the reprint was reflected):
<code>[Title "Friedrich Amelung, Düna-Zeitung 1897, Mate In Two (after ...g5)"]
[FEN "7R/6pp/5P1k/4PK1P/8/8/8/8 b - - 0 1"]
[startply "1"]
[startflipped ""]

1... g5 2. hxg6! Kh5 3. Rxh7#
</code>
There is no other possible Black move to reach the position after g5:
squares f6 and h6 are blocked, so the pawn didn't reach g5 by capturing;
bPh7 is on its starting square; Kg6-h6 would have WK and BK attacking
each other; and Kg7-h6 would require White's previous move to be with
the checking f6-pawn, which is impossible because e5,f5,g5 are all blocked
(the first of these is the only reason the e5-pawn is needed in the diagram).
As it happens, in this Amelung problem (unlike the more recent
Keller and Benkő problems suggested by Rewan Demontay) Black's g5
is not a blunder: any other move would also allow the same Rxh7 mate
in the next move or two.

Seeking a particular problem


How to prevent Richfaces popupPanel from being moved in JavaScript?

Question: Im using rich:PopupPanel components to display some content and I want them to be able to being maximized and restored by user. I've already implemented resizing and positioning of the component, but the problem is how to prevent popupPanel from being moved while it's maximized and allow it when its restored.
This is my code for button that is responsible for maximizing and restoring the popupPanel

<a4j:commandLink id="maximizeRestoreButton" execute="@none"
    render="@none" value="Maximize"
    oncomplete="
        var comp = #{rich:component(cc.attrs.popupId)};

        if (comp.isMaximized) {
            var rv = comp.restoreValues;

            comp.moveTo(rv.top, rv.left);
            comp.resize(rv.width - comp.width(), rv.height - comp.height());
            comp.isMaximized = false;
        } else {
            var rv = new Object();
            rv.top = comp.getTop();
            rv.left = comp.getLeft();
            rv.width = comp.width();
            rv.height = comp.height();

            comp.moveTo(0,0);
            comp.resize(window.innerWidth - comp.width(), window.innerHeight - comp.height());

            comp.isMaximized = true;
            comp.restoreValues = rv;
        }

        return false;" />

Answer: I will suggest you to use a popupPanel tags for perventing popup panel to move and resize instead of external js function. set movable=false and resizable = false in rich popupPanel tag. For E.g
<rich:popupPanel resizable="false" movable="false" ...>
.....
</rich:popupPanel>


Is a Hunter 2/Cleric 1 a 3rd-level caster?

Question: Can a third level character with two levels in hunter and one level in cleric cast as a third level caster?
Comment: Welcome to the site! Please take the [tour] when you get the chance. It's important to remember that there are thousands of RPGs out there; can you tell us which game and edition you're asking about?
Comment: The first suggestion by @MikeQ seems like it answers this question, but if it doesn't, could this question be edited to explain in greater detail what remains unclear? (No offense to Fering, but, Scott, as a (I assume) newer *Pathfinder* player, you may just be better off skipping to [KRyan's answer](https://rpg.stackexchange.com/a/130536/8610) to that question!)
Answer: No.
The rules for magic have this to say about caster level:

A spell's power often depends on its caster level, which for most spellcasting characters is equal to her class level in the class she's using to cast the spell.
Comment: So Hunter and Cleric both being Divine casting doesn't work like the example below with Wizard and Spellsinger Example: A Wizard 9/Spellsinger 2/Rogue 2 is Wizard Class Level 9, Spellsinger Class Level 2, and Rogue class level 2. Her Arcane Caster Level is 11, because Spellsinger adds to her arcane caster level... she casts as an 11th level wizard, but only has 9th level class features from wizard; her two levels of Spellsinger class levels giver her the 2nd level class features. Her Character Level is 13.     Also thanks for helping
Comment: @Scott Hunter and Cleric both lack any ability that advances the casting of other classes, they only advance their own.


offset in logistic regression to take into account a priori individual probability estimates

Question: I am performing a logistic regression (LR) model on a set of data on which an initial probability estimate for event occurrence, sai $\hat{p_i}^{base}$ has been provided. I have supplementary regressors and I want to update my model starting from the initial estimate. I was thinking to insert $logit\left(\hat{p_i}^{base}\right)$ as offset of the (LR) model, thus $logit\left(\hat{p_i}^{new}\right)=1*logit\left(\hat{p_i}^{base}\right)+x_i^T*\beta$. I am asking whether the offset form (logit) is the right functional form to allow for an initial "guessing" of the probability and if this is the most appropriate approach to update a logistic regression model, given initial updates. Thanks in advance for the attention.
Answer: If you wish to conduct Bayesian logistic regression with prior probabilities and updating, you must do Bayesian logistic regression with prior probabilities and updating.
A note about offsets: their general rationale is to re-express an outcome which is a ratio or difference of two values, one varying and one "fixed", by subtracting or dividing the "fixed" value from the LHS to incorporate it on the RHS with a fixed coefficient. This usually requires GLMs with collapsible links, like linear or Poisson regression. A difference in logit probabilities doesn't have any tangible meaning, we usually think of risk ratios or risk differences as meaningful comparative measures of two probabilities.
But more importantly, the reason why I believe it wouldn't work is that there is unaccounted correlation between your new (candidate) predictors and the old risk-prediction. For instance, suppose I predict cancer by age and obtain an cancer odds ratio of, say, 1.20 for a 5-year difference in age and linearity holds appropriately. I then obtain risk predictions for cancer. In another cohort, I measure smoking status in individuals. Suppose further there is a generational effect of smoking so that older individuals tend to smoke more, and thus partly explain the age-association with cancer. In a second model jointly adjusting for age and smoking status, the odds ratio for age is now reduced. In fact, because logistic regression is non-collapsible, coefficients will change upon further inclusion of uncorrelated predictors.
Hence, by including new covariates you cannot be guaranteed that the prior logit will have a coefficient of 1 against the posterior logit.
Comment: Hi @AdamO, I have some doubts on your answer. The prior assumptions are on the actual outcomes, whilst they are set on coefficients following a Bayesian approach, as far as I know. I was thinking to use the logit of prior estimates as a "starting coefficient", so i probably should have written "initial" instead of a priori.
Comment: @GiorgioSpedicato Thanks for clarifying. That only pertains to the first sentence of my answer. What about the rest?


Moduli spaces of complex curves as algebraic varieties

Question: Using a minimum of technical vocabulary, give a summary of why it is that the moduli space of genus g complex curves with n marked points has a natural compactification that is isomorphic (as a complex orbifold) to a projective algebraic variety.
Comment: Well, actually what you write is not precisely true. In general you don't get a complex manifold, just because the thing you get is not smooth. But it is a smooth orbifold.
Comment: I changed 'manifold' to 'orbifold' (you still have a complex structure, right?)
Answer: The classical (pre Deligne-Mumford) approach is to map $\mathcal{M}_g$ into $\mathcal{A}_g$ using the Torreli map. Whereas the classical way to see that $\mathcal{A}_g$ is quasi-projective is to define it as the Siegel upper half space $\mathcal{H}_g$ ($g$ by $g$ complex matrices with positive define imaginary part), modulu $\mathrm{SP}(2g,\mathbb{Z})$; We define the level cover $\mathcal{A}_g(m)\to\mathcal{A}_g$, which is the moduli of $\mathcal{A}_g$ plus torsion points, which is the quotient of $\mathcal{H}_g$ by $\Gamma(m)$ (the matrixes in $\mathrm{SP}(2g,\mathbb{Z})$ which are trivial modulo $n$), and send $\mathcal{A}_g(m)$ to some projective space using polynomials in the theta constants.
Reference (for both Torreli and the embedding of $\mathcal{A}_g$ above) : Mumfords curves and their Jacobians (now bundled together with the red book in LNM 1358) Lecture IV.
In Lecture II (same place) Mumford sketches two more "coordinate oriented" methods

Tracking the Weierstrass point of
curves.
Tracking invariants of the
Chow form of the canonical curve (the
Chow form is the equation for pairs
of hyperplanes such that $H_1 \cap H_1
   \cap$ canonical-curve is not $0$).

He also says these are the only "coordinate oriented" methods he knows of.
Comment: As for why being a locally closed subset of a quasi-projective variety, you can then embed the quasi-projective into projective space, and then the locally closed subset will be locally closed in P^n, and so its closure is projective.  As for why A_g is quasi-projective...can't help.
Comment: David - Thanks for the remark and especially for the reference to the Mumford book. If it's not too hard to do so, could you expand on why it suffices exhibiting Mg as a (suitable kind of) subset of a quasi-projective variety and why Ag is a quasi-projective variety?
Comment: @Johan: Charles is of course correct about your first question, and I edited my answer to answer the second; sorry about the delay - I'm on the other side of the globe.
Comment: 'Torelli' and not 'Torreli'...
Answer: I'm not sure how useful this will be, but I can say a couple of words about why A_g is quasiprojective (I am very much not an expert, so real experts are welcome to correct me).  This will be an outline of what happens in the proof, but without going into the details I can't explain why this works.
There are probably fancier ways of doing this, but the most classical is via the theta constants.  The best complete reference for this is Igusa's book "Theta Functions", but a large part of the story can also be found in Mumford's "Tata Lectures on Theta I", which is easier to read.  In particular, the 1-dimensional case is worked out there very explicitly, and if you want to understand the details I would try to understand this case first.  By the way, in the 1-dimensional case we have A_{g} = M_{g} since every elliptic curve is isomorphic to its Jacobian.
The basic idea is that theta functions provide a natural set of coordinates on A_g.  These coordinates give an embedding into projective space, and the compactification is the closure of this embedding.
A point of A_g is a complex tori T that happens to be a projective variety (together with a principal polarization, but don't worry about that now).  A theta function on T is a holomorphic function on C^g (the universal cover of T) that satisfies a simple transformation law (it is really a section of a certain bundle on T lifted to the universal cover C^g).  The set of all theta functions on T spans a finite-dimensional vector space, and you can use them to embed T into projective space.
Our goal, though, is to embed A_g into projective space.  The universal cover of A_g is the Siegel upper half plane H_g, which is a nice complex domain.  In fact, it is the set of all skew-symmetric gxg complex matrices whose imaginary part is positive definite (for g=1, this is exactly the classical upper half plane).  One now looks at the set of all holomorphic functions F(.,.) on H_g x C^g such that for all T in H_g, the function F(T,.) is a theta function on T.  This again spans a finite-dimensional vector space.  Every PPAV has a distinguished point, namely 0.  The "theta constants" or "theta nulls" are the functions F(.,0) on H_g.  These satisfy a (somewhat complicated) transformation law on H_g coming from the fact that they are sections of a certain bundle on A_g.  These theta-nulls give you an embedding into projective space, and thus a compactification.
Comment: I think the only non accurate part here is that you are using torsion points (and in fact, as far as I recall, you need more then 2-torsion), so what you get is a representation of a finite cover of Ag, and not Ag itself
Comment: That's right -- you are really working with the A_g(L) for L at least 3 so that you are working with a smooth space rather than an orbifold (here A_g(L) is the moduli space of PPAV's with level L structures).
Answer: Technically I recall from the Tata lectures, that it is Ag(4,8) that embeds via theta nulls.  Another nice reference is Freitag's book on Siegel modular functions.
Answer: The moduli space $\overline{M}_{g,n}$ has a structure of orbifold or in algbraic terms of Deligne-Mumford algebraic stack.
Since the deformations of $n$-pointed genus $g$ Deligne-Mumford stable curves (at most nodal singularities and finite automorphism group) are unobstructed the stack is smooth of dimension $3g-3+n$.
The corresponding coarse moduli space $\overline{M}_{g,n}$ is a projective variety with quotient singularities at the places where the automorphisms groups of the curves jump.
To understand why it is projective one can consider the usual GIT construction. One can embed a curve of genus $g\geq 2$ in $\mathbb{P}^{N}$ with the sections of the $3$-canonical system. The action of $SL(N)$ on the Hilbert scheme $H$ of such curves can be linearized. Then one construct $\overline{M}_{g}$ as $H/SL(N)$. Now the projectivity follows from the projectivity of $H$ and standard theorems of GIT.


How do Continuationists discern between genuine and made-up interpretations of tongues?

Question: When someone claiming to have the gift of interpretation of tongues interprets someone else's tongue speaking, how do Continuationists (e.g. Pentecostals, Charismatics, etc.) go about determining whether the interpretation is genuine or made-up? How do they tell whether someone's tongues are genuine and someone else's interpretation is also genuine? What is the biblical basis for their "discernment procedure", if any?
Comment: Are you asking how one would know if someone else is telling a lie ? It is often very obvious when someone tells lies.
Answer: My godmother spent a lot of time in Charismatic churches. She said that anyone who made themselves the center of attention every week was faking it. That's not based on a Biblical passage but it's remarkably useful.
Comment: Welcome to Christianity Stack Exchange.  We're different to a lot of other sites so please take our Tour to find out what we look for in well-researched answers: https://christianity.stackexchange.com/tour


Oracle Data Provider for .net

Question: I would like to know whether there is a difference in functionality between ODP.net for .net 1.1 and ODP.net for .net 2.0 or higher. Are there any performance differencies?
Answer: It depends... 8-)
The provider for .Net 2.0 support more advanced features that allow data insertion and retrieval operation to be much faster but you need to change your code to use them.
If you're willing to change your code and need the new features improvement could be very effective (for example the array parameter functionality could really speed up massive insert operation, I do not remember if it's available in the 1.1 provider but I do not think so).
As for simply using the same code in Microsoft.NET 1.1 with ODP.Net 1.1 or using with Microsoft.NET 2.0 and ODP.Net 2.0 I do not think you will see great improvements.

Oracle Data Provider for .net


Could an incorrect substitution result in a forfeit?

Question: In a football match, one team said that they would replace player A with player B, but they actually replaced player C instead, and continued to play the game. Is it possible that this would result in a forfeit under the FIFA laws?
Comment: I would guess forfeiture of fixtures will be regulated by the individual tournament rules. I've looked through the Premier League handbook and there's no such clause for this particular case, but a replay of a fixture can be ordered under various circumstances. If player `C` was otherwise eligible, I don't see how that could result in anything other than a fine.
Answer: This could not be a forfeit under the Laws of the Game as the Laws make no mention of forfeits. So long as the referee (and other officials) are clear as to which player was being substituted, there isn't a problem here - and if the referee wasn't clear as to which player was being substituted, they should not have allowed the substitute to enter the pitch until it was clear.


Buddhas (and Bodhisattva) are real individuals or manifestations?

Question: As early as Mahasamghika schools of Buddhism there was a view that there are countless Buddhas in the ten directions, that all Buddha's have one body (dharmakaya), and that they are just manifestations (nirmanakaya). The last part says how Buddhas, including Gautama, didnt and dont actually ever get hungry, or eat, or got dirty, or defecate, or struggle to achieve enlightenment, or grow old and die, but that all that is for show, a part of teaching people. Are all Buddhas like this, just like some 'holograms' that Dharmakaya projects in various world to teach people? If that is the case, that seems to imply that we cant actually become Buddhas, because the Buddhas are just manifestations. I know the stories in some Sutras about how some humans aeons ago made vows to become a Buddha and now they are a Bodhisattva (such as Avalokitesvara) or a Buddha (such Amitabha), but if that is also all just for show, skillful means to teach people, it seems there are no examples of actual people becoming a Bodhisattva or Buddha..? Whats going on there?
Answer: I believe that the concepts of Dharmakaya (eternal truth form) and Nirmanakaya (physical form) originated from the following sutta quote.
The Buddha downplayed the importance of his physical form and advised Ven. Vakkali to focus on the teachings, stating that when one sees the Buddha, one sees the Dharma (teachings), and when one sees the Dharma, one sees the Buddha.
In other words, the Dharma is what the Buddha stands for, and the Dharma is what the Buddha represents. The Dharma (teachings) is his eternal "form".

Vakkali: "For a long time, venerable sir, I have wanted to come to see
the Blessed One, but I haven't been fit enough to do so."
Buddha: "Enough, Vakkali! Why do you want to see this foul body?  One
who sees the Dhamma (teachings) sees me; one who sees me sees the
Dhamma (teachings). For in seeing the Dhamma (teachings), Vakkali, one
sees me; and in seeing me, one sees the Dhamma (teachings).
Vakkali Sutta (SN 22.87)

I believe that the concept where the Nirmanakayas of all the past Buddhas emanate from one Dharmakaya originates from the following sutta quote.
It simply means that all the past and future Buddhas rediscover, understand and teach the same Dharma (teachings), because it is the natural law.
Hence their physical appearance as teachers, emanate from the Dharma (teachings) as their one eternal "form". In other words, all the Buddhas stand for the same Dharma (teachings) and all the Buddhas represent the same Dharma (teachings).

Past Buddhas,
future Buddhas,
& he who is the Buddha now,
removing the sorrow of many —
all have dwelt,
will dwell, he dwells,
revering the true Dhamma.
This, for Buddhas, is a natural law.
Therefore one who desires his own good,
aspiring for greatness,
should respect the true Dhamma,
recollecting the Buddhas' Teaching.
Garava Sutta (SN 6.2)

"Was the Buddha a real individual?" is answered in the Yamaka Sutta (SN 22.85). I leave it to you to read it.
And what about the Sambhogakaya (enjoyment/ reward form, or perhaps inspirational form)?
I speculate that it's related to the following quote.
When one recollects the Buddha, who he was, what he achieved, what he contributed and what he stood for, that person becomes inspired and his fears dispelled. So, this inspirational mental image of the Buddha is the Buddha's inspirational "form". He can manifest in this "form" to inspire and dispel fear.

But bhikkhus, I say this: If you have gone to a forest or to the foot
of a tree or to an empty hut, and fear or trepidation or terror should
arise in you, on that occasion you should recollect me thus: 'The
Blessed One is an arahant, perfectly enlightened, accomplished in true
knowledge and conduct, fortunate, knower of the world, unsurpassed
leader of persons to be tamed, teacher of devas and humans, the
Enlightened One, the Blessed One.' For when you recollect me,
bhikkhus, whatever fear or trepidation or terror you may have will be
abandoned.
Dhajagga Sutta (SN 11.3)
Comment: Very good quotes from the Pāli Canon. IMO, you should also consider that the version of the Buddha that is marked with 32 mythohistorical "marks of a Great Man" might be the precursor of the saṃbhogakāya. In certain suttas, people cannot identify the Buddha, believing him to look like "an ordinary monk." This is contrasted with passages in which the Buddha appears godly and otherworldly, with the 32 marks. In some passages, people have to use psychic powers in order the perceive the Buddha's marks. The saṃbhogakāya is the body of the Buddha that appears in deep samādhi. Similar no?
Comment: Sure, that's a Theravada explanation, I should have maybe explicitly pointed out that I am interested in a Mahayana (or Vajrayana) explanation..
Comment: @zelenisok The Pali suttas of Theravada is more-or-less the same as the Mahayana Agamas which is considered part of the first turning of the wheel. So, it's pretty much a part of Mahayana.
Answer:
Are all Buddhas like this, just like some 'holograms' that Dharmakaya projects in various world to teach people?

Actually, and to be clear, I don't think even the most hardcore Mahayanists would propound such notion. That's why they proposed the Trikaya model (composed of 3 separate bodies), not as a contradiction to the Theravada's notion, but as an extension. Both schools agree on the Nirmanakaya part, the physical body's appearance in the world (ie the historical Gautama Buddha). Then the Mahayanists added 2 more as an extension to that: Dharmakaya, the Dharma-body/utimate-reality/pure-being (which associates with Vairocana), and Sambhogakaya, the Enjoyment/Bliss/Divine-body (which associates with Amitabha).
Comment: Would they say that Dharmakara was an actual individual like you and me who then became Amithaba, or was all of that for show, just skillful means that the Dharmakaya did (physically, not as a hologram) in order to teach people? That's my main question.
Comment: @zelenisok, I don't think the Dharmakaya is a physical representation because there's already the Nirmanakaya that fulfills that role. So, Dharmakaya provides a more of an abstract representation representing the Buddha's Doctrines and/or His Buddha Nature.
Comment: I meant the monk Dharmakara, -ra at the end, not -ya. He is said to have been a monk who make 48 bodhisattva vows and eventually became Amitabha. And my question is was Dharmakara a real person like you and me, or was he was the Nirmanakaya of the Dharmakaya.
Comment: @zelenisok, ah ok i see, well, Amitabha Buddha is not a human like you and me because He does not live on earth like Gautama Buddha. Instead, He lives in a non-human realm called the PureLand, so technically speaking, He is not human. And that's why He represents the Sambhogakaya, not Nirmanakaya (which is Gautama Buddha, a human), nor Dharmakaya (a higher abstract representation of the Doctrines and/or Buddha nature)
Answer: The trouble with statements about the Mahāsāṃghikas is that they are a very poorly-attested school. We don't have very many Mahāsāṃghika-specific documents at all. Sometimes, doctrines are only substantiated through heresiologists in heresiological texts, meaning that they show up attributed to the Mahāsāṃghikas in sectarian works by other schools. Heresiologists cannot necessarily be trusted to give accurate and fair descriptions and assessments of the doctrines of other schools, particularly ones that they think are "heretical."
The English term "heresiologist" generally refers to Christian writers of the first to fifth century, like Irenaeus for example, who wrote polemical treatises refuting heterodox Christian groups like various kinds of Gnostics and Manichaeans, etc. Perhaps the most famous heresiological text is Irenaeus's Adversus Haereses, or "Against the Heresies." In studying Buddhist history, we find a similar literary genre emerging amongst the schools and sects of early Buddhism. Authors take up the mantle of heresiology in order to lineate and address the differences in these various sects -- both differences of doctrine as well as differences in how they have preserved and transmitted the Buddha's words.
Examples of heresiological texts from which Mahāsāṃghika doctrines are divined are the Samayabhedovyūhacakra of Venerable Vasumitra and the Mahāvibhāṣa of Venerable Katyāyāniputra. Both of these texts seek to lay out the "heresies" of various schools, including the Mahāsāṃghikas, and also to lay out the "correct orthodoxy" of the Sarvāstivādins at variance with the "heresies" of the various schools.
It's easy to see how heresiological texts are not ideal for reconstructing the authentic practices of a religious community (after all, their purpose is to polemicize and criticize), but when they are all one has, one has to make do. The plenteous and well-established Southerly Āndhrakas ("Caitikas"), who were well-established enough to be preserved in the historical memory of the Theravādin communities that transmitted the Kathāvatthu, leave us none of their own manuscripts due to the climate of Southern India and when their sect died out. It's similar to why there are few Sri Lankan manuscripts substantiating the Pāli Canon that are very old: they decompose in the wet tropical climate.
With that in mind, we can turn to three questions raised by the OP in light of both native Mahāsāṃghika sources as well as in light of heresiological texts addressing the Mahāsāṃghikas.

As early as Mahasamghika schools of Buddhism there was a view that there are countless Buddhas in the ten directions,

If you can manage, purchase Les sectes bouddhiques du petit vehicule by André Bareau or view it online. This is a seminal text in Mahāsāṃghika studies. It was translated into English, but I can't remember the name of the translator. In it, you will find a list of Mahāsāṃghikas doctrines taken from the Samayabhedovyūhacakra. They include:

The knowledge of destruction and non-arising continue unceasingly
until final nirvāṇa – Since the 18 elements which make up the Buddhas
are free from impurities, knowledge free from impurities is constantly
present.

The Buddhas abide in all directions – There are Buddhas in all
directions, in all the universes, everywhere.

The Buddhas exists as substance (dravya).

When the Buddhas enter the womb, they do not go through the impure
stages of embryonic development. They enter fully developed and do not
need impure material such as sperm to be born.

In total, there are 51 "heretical" theses attributed to the Mahāsāṃghikas in Ven Vasumitra's Samayabhedovyūhacakra. These are 14-18. As you will see, the bolded section lays out the doctrine of "contemporaneous Buddhas."
This is all fine and dandy, but can we find this actually substantiated in a native Mahāsāṃghika document? Yes, actually. We can find it in the Ekottarāgama and in the Mahāvastu and in the Lokānuvartanasūtra, which is a commentary on the Mahāvastu. These are some of the only Mahāsāṃghika documents that survive, so it's good that they happen to have these attested.
The Japanese scholar Nishio Kyoyu argues that the doctrine of "many Buddhas" present in the Ekottarāgama is distinct from the scriptures of other early Buddhist schools. See p. 99 of The Evolution of the Concept of the Buddha from Early Buddhism to the Formulation of the Trikaya Theory by Guang Xing.
Furthermore, in the preamble to the Mahāvastu, we read:

Homage to the glorious mighty Buddha, and to all Buddhas, past, future and present.

(Mahāvastu opening, translated by Dr. J.J. Jones)
This expression, "Buddhas of the past, future, and present" (Pāli: atītānāgatapaccuppanna) is a very common expression that you can find in EBTs including the Ekottarāgama. There is a passage substantiated between the Pāli scriptures and the Mahāsāṃghika scriptures where the Buddha says "Buddhas of the past, Buddhas of the present, and Buddhas of the future." It is the Gāravasutta of SN 6.2. In the Pāli version, the Buddha just says "Buddhas of the past, Buddha of the present, and Buddhas of the future." The Pāli version has just one Buddha in the present, in-line with Theravādin doctrine.
From the Mahāsāṃghika Mahāvastu as translated by Émile Senart:

ye cābhyatītā saṃbuddhā ye ca buddhā anāgatā | ye caitarahiṃ
saṃbuddhā bahūnāṃ śokanāśakā | dharmaṃ deśenti satvānāṃ buddhānaṃ eṣā
dharmatā ||
The perfect Buddhas that have been, those yet to come, and those that now are, the dispellers of the sorrows of the multitude, all have taught, will teach and do teach dharma to men, for such is the obligation of Buddhas.

This is the Pāli version as translated by Venerable Sujāto:

Ye ca atītā sambuddhā, ye ca buddhā anāgatā; Yo cetarahi sambuddho,
bahūnaṁ sokanāsano. Sabbe saddhammagaruno, vihaṁsu viharanti ca; Tathāpi viharissanti, esā buddhāna dhammatā.
All Buddhas in the past, the Buddhas of the future, and the Buddha at present, destroyer of the sorrows of many, respecting the true teaching
they did live, they do live, and they also will live. This is the nature of the Buddhas.

The Mahāsāṃghika account differs in the pluralization of two words, both relating to the existence of "Buddhas," plural, in the present, as well as having the end of the section differ.

that all Buddha's have one body (dharmakaya), and that they are just manifestations (nirmanakaya)

The Buddhāvataṃsaka states: "the Dharmakāya is one." The Agrajñasūtra states: "The Buddhas of the past, future and present are equal, because the Dharmakāya is one" (T10.592c translated by Guang Xing). These are both Mahāyāna texts however, and while  Mahāsāṃghika was clearly highly influential on the Mahāyāna, we can't utterly conflate the two. From outrightly Mahāsāṃghika documents, we get: "The Buddha can manifest himself in numerous bodies and appear in countless lands, but the body of the Buddha neither increases nor decreases," and "All Buddhas have one body, the
body of the Dharma" (see p. 103 in aforementioned article).

Buddhas, including Gautama, didnt and dont actually ever get hungry, or eat, or got dirty, or defecate, or struggle to achieve enlightenment, or grow old and die, but that all that is for show, a part of teaching people.

I would like to quote at length from the commentary to the Mahāvastu here, as I feel it would be an appropriate way to end this post. Apologies if this is overlong:

Although the Buddha abides in the world but he does not attach to it,
he is a light to the world. All his bodily actions, words of the mouth
and thoughts of the mind are in conformity with the ways of the world.
Thus he cultivated his mind. No one can surpass the teachings of the
Buddhas and no one can achieve the works of the Buddha. It is in
conformity with the ways of the world, but there are none who know.
The Buddha, out of compassion for the people of the ten directions,
illuminates the world by preaching the Dharma in accordance with the
likes of the world.
The Bodhisattva was not born from the sexual union of father and
mother. His body is magically produced, like illusion. He makes a show
of having father and mother. It is in conformity with the ways of the
world that he makes such a show.
The Buddha has an immeasurable light which illuminates the ten
cardinal directions. It is in conformity with the ways of the world
that he makes a show of having a light of seven chi only.
The Buddha has never touched the ground with his feet, but the marks
imprint on the ground. It is in conformity with the ways of the world
that he makes such a show.
Since many thousand myriad kotis of asamkhyeyakalpas ago the Buddha
has accomplished prajnaparamita. It is in conformity with the ways of
the world that he made a show of being a small boy.
The Buddha illuminates men of the ten directions in darkness. It is in
conformity with the ways of the world that he makes a show of having a
wife and a child.
When the bodhisattva was born and walked on the ground he uttered the
words: "In the whole world no-one surpasses me! I shall deliver men of
the ten directions!" It is in conformity with the ways of the world
that he makes such a show.
Some ask that since the prince sat at the foot of a tree in
Jambudvipa, there had been six years of suffering with endeavour. It
is in conformity with the ways of the world that he makes a show of
suffering.
The Buddha sat alone at the foot of the tree when he is about to
attain enlightenment. It is in conformity with the ways of the world
that he emits rays of light to inform Mara of his state.
The Buddha accomplished wisdom which is equal to all Buddhas and there
are none who can surpass it. It is in conformity with the ways of the
world that he makes a show of having obtained Buddhahood and sits in
peaceful seclusion.
The purpose of attaining Buddhahood is to preach the Dharma in order
to save the people of the ten directions out of compassion. But the
Brahma Sahampati pleads the Buddha to deliver the Dharma to people. It
is in conformity with the ways of the world that he makes such a show.
There is nothing which can either increase or decrease the wisdom of
the Buddha. It is in conformity with the ways of the world that he
makes a show of having more or less wisdom.
The Buddha abides in tathata and emptiness so he does not come and
does not go. It is in conformity with the ways of the world to say
that the Buddha appears in the world and enters into parinirvana This
is just a show.
The Buddha abides nowhere just as the empty space that abides nowhere.
It is in conformity with the ways of the world to say that the Buddha
lives. It is only a show.
The Buddha's feet, like lotus flowers, do not get dirty, but the
Buddha washes his feet. It is in conformity with the ways of the world
that he makes such a show.
The Buddha's body, like gold, does not get dirty, but the Buddha makes
a show of taking a bath. It is in conformity with the ways of the
world that he makes such a show.
The Buddha's mouth is fundamentally clean, with a fragrance like that
of kunkuma. Nevertheless the Buddha cleans his mouth with poplar
twigs. It is in conformity with the ways of the world that he makes
such a show.

(from the linked article, translated by Guang Xing)
I've bolded one of the elements in this long litany, namely the part concerning itself with the Buddha's halo/aura. We can use this Mahāsāṃghika doctrinal point to illustrate further similarities between the Mahāsāṃghika "High Buddhology" and later Mahāyāna Buddhology.
Here is a depiction of the Buddha's halo from a piece of traditional Sri Lankan artwork:

We can see the distinct colours, a tradition dating back to the EBTs ("Early Buddhist Texts"). It appears in the Pāli vinaya, in the Atthasālinī (part of the "Great Commentary"/Mahāṭṭhakathā of the Theravādin sect), and in the Sarvāstivādin Saṃyuktāgama (Sūtra No. 197).
In this Mahāsāṃghika commentary above, it is explained as being for the sake of conformity with the world that the Buddha limits the size of his halo of light. Now we come to a much later text Mahāyāna text from the same vein of Buddhist thought that will greatly elaborate on this sort of belief concerning the Buddha's halo that seems to be shared between Mahāyāna and earlier Mahāsāṃghika Buddhism.
From a famous apocryphal commentary to the Pañcaviṃśatisāhasrikāprajñāpāramitāsūtra, namely the Mahāprajñāpāramitopadeśa as translated by Venerable Migme Chodron:

Sūtra: Atha khalu Bhagavān prakṛtiprabhayā trisāhasramahāsāhasraṃ
lokadhātum avabhāsayāmāsa. yāvat pūrvasyāṃ diśi gaṅgānadīvālukopamā
lokadhātavas tayā prabhayā avabhāsitā abhūvan. yāvat daśasu dikṣu
gaṅgānadīvālukopamā lokadhātvas tayā prabhayā avabhāsitā abhūvan. ye
ca sattvas tayā prabhayā spṛṣṭās te sarve niyatā abhūvan anuttarāyāṃ
samyaksaṃbodhau.
Then by means of his usual light (prakṛtiprabhā) the
Bhagavat illumined the trisāhasramahāsāhasralokadhātu; this brilliance
extended to all the universes of the east as numerous as the sands of
the Ganges, and it was the same in the ten directions. All the beings
who were touched by this light were destined to supreme complete
enlightenment.
Śāstra: First the Buddha smiled with his entire body then he emitted
rays from the pores of his skin; why now does he exhibit his usual
light to light up the ten directions?
Some people who have seen the different rays [shooting out from the
body and the pores of the Buddha] believed that this was not the light
of the Buddha. [Now] seeing the great development of the usual light
of the Buddha, they are filled with joy and, recognizing the true
light of the Buddha, they finally reach anuttarasamyaksaṃbodhi.
What is the usual light of the Buddha?
It is a light one armspan in width surrounding the body of the Buddha
on all sides; the Bodhisattva possessed it since his birth and it is
one of the thirty-two marks called vyāmaprabhālakṣaṇa.
Why is the usual light of the Buddha one armspan in width and not
larger?
The usual light of the Buddha is immense and lights up the universes
of the ten directions. The miraculous bodily light of the Buddha
Śākyamuni is immense; it is the width of one armspan, a hundred
armspans, a thousand prabhedakoṭi of armspans and fills up the
trisāhasramahāsāhasralokadhātu and the ten directions. However, the
Buddhas' custom is to manifest in the world of the five corruptions,
where beings are of middling qualities and knowledge, a brilliance of
only one armspan. If he showed a larger brilliance, the people today,
of little merit and weak faculties, would be unable to tolerate the
light. When a person sees a god, his eyes are blinded because the
greater the light, the more the eye contracts. It is to people of keen
faculties and eminent merit that the Buddha shows his immense
brilliance.
Besides, there are people who, seeing the usual light of the Buddha,
rejoice and find salvation.
The king makes a gift of the leftovers from his usual table to his
inferiors, and the latter receive them rejoicing greatly. The Buddha
does the same. Some people feel no joy in seeing the other many lights
of the Buddha but, on contemplating his usual light, they are destined
to anuttarasamyaksaṃbodhi.

This later texts goes to lengths to stress its "literalist" reading of the Buddha's halo. For the author of this text, the Buddha's halo is "actual light," i.e. "electromagnetic radiation" to a modern, that could conceivably light a room. In the later text, the light is specifically not a mental light or a mentally-perceived light that is seen in deep meditation. Food for thought.
Tl;dr:
All three doctrines are substantiated both in native Mahāsāṃghika texts and in texts from other sects that talk about the Mahāsāṃghikas. The Mahāsāṃghikas had a pseudo-"docetic" understanding of the physical body of the Buddha. (see docetism for a Christian parallel) While it, the physical body of the Buddha, appeared to the people of the world, it was not truly the Buddha's body and was not truly a physical body. Furthermore, we can see a direct line of contintuity between Mahāsāṃghika and later Mahāyāna thought through a passage about the Buddha's halo.
With that, we come to the second part of the OP:

If that is the case, that seems to imply that we cant actually become
Buddhas, because the Buddhas are just manifestations.

"You" are just a manifestation. What are you a manifestation of? Several Pāli suttas would suggest "clinging" or "suffering" to be the answers.

I know the stories in some Sutras about how some humans aeons ago made vows to
become a Buddha and now they are a Bodhisattva (such as
Avalokitesvara) or a Buddha (such Amitabha), but if that is also all
just for show, skillful means to teach people, it seems there are no
examples of actual people becoming a Bodhisattva or Buddha..? What's going on there?

There is, ultimately speaking, no such thing as "a sentient being." This is the most difficult teaching of the Buddhas. "Actual people" is a delusion. "The person" is a delusion; "the being" is a delusion. As Venerable Śailā once said to Māra:

You say that there are "sentient beings." That is Māra's view. There
are only the empty aggregates assembling. There are no "sentient
beings." It is like when the many materials converge and the world
calls it "a chariot." The many aggregates, via the conditions,
converge. "Sentient being" is a designatory label. That arises,
consequently suffering arises. (That) Abiding, also, is none other
than suffering abiding. Nothing else arose but suffering. Suffering
arose, and suffering itself will cease.

(Saṃyuktāgama Sūtra No. 1202)
"There are only the empty aggregates assembling." In the Mahāyāna, we can speak of the Buddha as with "no aggregates to speak of," or we can speak of the Buddha as with "five pure aggregates." What are the Buddha's Five Pure Aggregates? They are pure śīla (ethics), pure samādhi (meditation), pure prajñā (wisdom), pure vimukti (deliverance/liberation), and pure vimuktijñānadarśana (gnosis and beholding of deliverance/liberation). See section 4 of the Buddhānusmṛti division of the Mahāprajñāpāramitopadeśa here.
The Flower Garland speaks of "saving beings with no notion of a being" (救護一切眾生離眾生相) at the heights of Buddhist practice. It's a mystery known only to the Buddhas and the Āryan saints, the Āryabodhisattvas.
Comment: That last part about there being no persons is a Theravada teaching (and not even of the whole Theravada, some Theravada traditions such as Thai forest, Dhammakaya and some Burmese traditions disagree with that reduction of individuals to the aggregates) my question was about the Mahayana /Varjayana perspective. A person / mind / root consciousness is posited beyond the five aggregates, we are not illusions. Even in Madhyamaka and Yogacara views we exist (just mentally, not physically). Maybe the solution is an advaita interpretation, like some in Thai forest tradition interpreted citta.
Comment: Actually, it's from the Sarvāstivādin Saṃyuktāgama. It's not Theravādin, although the Theravādins do transmit a parallel passage (they attribute the gāthā to a certain "Venerable Vajirā"). The Prajñāpāramitā and Madhyamaka also say the same thing concerning the artifice of "the person" or "the being."
Comment: Something else of note is that the Northern parallel specifies "empty aggregates assembling" whereas the Pāli version simply specifies that there is only the heap of saṃskārās. Also, look up Ven Candrakīrti's Madhyamaka commentary, the Madhyamakāvatāra, and see the "sevenfold reasoning of the chariot," wherein Ven Candrakīrti quotes from this āgamasūtra (or quotes the Nāgasenabhikṣusūtra) and explains it at length.


Why should I avoid using the pith section of quarter sawn lumber?

Question: The title pretty much sums it all up. When selecting quarter sawn lumber, why should the very center (pith) be avoided?
Comment: if you buy a wider board and cut either side of the pith, you'll have nice quartersawn lumber
Answer: The pith is what remains from the time when the tree was but a lad. It's soft and weak. Using it in woodworking would be like making something out of a bush. When the pith is exposed on two faces of a board, it will often crack and fall out.
It's also under stress. If you look at 4x4 posts at HD or Lowes, you'll notice that many of them have a split that runs from one face down to the pith. If you're going to make something that includes the pith (called "boxed heart"), you can make a cut that mimics this split and reduces the tension. Japanese woodworkers like to make this cut and then insert a piece of softwood to cover it up.
Comment: "LIBRARY" says the guy on the internet?  :)
Comment: Good to know, since you just saved me from naively using a pith section in my next project!
Comment: I'm interested in the japanese use. I'm going to have to research...BACK TO THE LIBRARY!
Comment: "LIBRARY" concurs this guy. Don't trust anything written after WWII when discussing technique. When it comes to really understanding how wood moves and settles, don't trust anything written after the civil war.


Can't log in as admin

Question: Someone let us know about an error on our site. I logged in (as an admin). I was able to move the site to maintenance mode and then went through the steps to clear the cache on the site. Once I did that, I am no longer able to log in or even get to the log in page.  I went to our site: safefields.org/user and I get this error: safefields.org is currently unable to handle this request. HTTP ERROR 500  How can I fix any of this if I can't even log in?
Comment: "HTTP ERROR 500" will leave an entry in your webserver error log. Look at that error and it should tell you a lot about what happened. In general, visiting safefields.org/user should allow you to log in a the admin user.
Answer: When you type in safefields.org/user your site immediately redirects to the login page safefields.org/user/login which I believe indicates that your Drupal site is running but gives you a WSOD (white screen of death).
Usually that is because of a memory_limit constraint.
Things to investigate:

Try to use Drush to set the maintenance mode back to 0: drush vset maintenance_mode 0 this should get your site visible again
Check your settings.php and see if you have a memory_limit set there, increase to 512M or higher clear cache (either via Drush or empty cache tables directly in the database)
Check your php.ini file either in the root of your site's folder or in your public_html folder and increase it in size.
Google "Drupal 7 WSOD" as they say: add error reporting to your settings.php file to see what the errors are so you can search more effectively for what's causing your problem. https://www.drupal.org/node/158043

error_reporting(-1);
$conf['error_level'] = 2;
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);

Can't log in as admin


How to disable flashing file names in rlogin

Question: I have a strange problem with my rhel 6.4 system.
If I do a rlogin to any of my machines, all the files in the remore machine will be flashing and it is so annoying.
Can somebody please tell me how can I disable this?
Comment: A file is an invisible collection of bits on a disk. It could not possibly flash. Perhaps you mean some other flashy things, like *file names as shown by **ls** in the terminal*.
Comment: ya... the files which are listed after the ls command are flashing.
Answer: There are several reason why the output of ls would blink. Here are some, roughly in a decreasing order of probability.

Your $LS_COLORS environment variable is set incorrectly.
Your $LS_COLORS environment variable is not set and your /etc/DIR_COLORS file is corrupt.
Your $TERM environment variable is set incorrectly.
All your files are in fact orphaned symbolic links.

A reasonably set $LS_COLORS should contain substrings like or=01;05 and mi=01;05 and there should be no more 05s. Likewise, a reasonable /etc/DIR_COLORS should contain 05 in two places, near words ORPHAN and MISSING.
These settings make sure that ls shows just orphaned symbolic links, and missing files they point at, in blinking characters. 05 or 5 is the ANSI terminal escape code for blinking.


Is this fuse a good choice for my Prusa i3's power supply and RAMPS 1.4?

Question: Wondering if this fuse is safe to use in this switch/plug to turn on /off a 12V DC 30A Power Supply 360W Power Supply that will power a RAMPS 1.4 board for a Prusa i3 with an external led display that contains an SD Card Reader.
I found the suggestion to use it here.
Comment: It's really not a 3d printer question, it's an electrical engineering question that just happens to be about a 3d printer.
Comment: Fair point. Maybe the question could be "Is this fuse a good choice for my RAMPS Prusa i3?" or something like that :-)
Comment: What's with the down vote?  You be troll'n?
Comment: @RyanCarlyle oh, well somebody move it to the Electrical Engineering Stackexchange then...no that's a bad idea, this site is in beta and needs the help.
Answer: No, do not use this fuse. The current rating is too high to be reasonable for your printer. It will "work" in the sense that your printer will get power, but it won't provide anywhere near as much protection as a lower-rated fuse.
10A is a lot of current for mains voltage. Depending on what else you have plugged in, there is a fair chance your home's 15A breaker will trip before this fuse does, which kind of defeats the point of having it.
Even for "fast" fuses, it takes a significant amount of time for them to blow when conducting their rated current. The internal fusible link has to heat up and melt before the fuse stops conducting. The less the overload current exceeds the rating, the longer that takes. A 10A fuse conducting a 10.5A short might take 30 seconds to trip. In the meantime, your printer is melting. Lower-rated fuses will trip faster for the same short and thus provide better protection.
You need to size fuses as small as possible for the required current draw if you want to have any hope of rapidly cutting off an excessive-current event.
I would recommend a 4A fuse in the USA for this 350w power supply. (Note: the listing title says 360 but the photos show 350.) I use 4A fuses in several printers with 120v / 350w PSUs and they do not trip. But you can do the math for yourself:
350 watts / 120 volts / 80% efficiency = 3.64A
The smallest fuse you can find that is larger than this value is what you should use.
Now, we can argue over whether 80% is the right efficiency value... it could be lower. The PSU label says 6.5A input is required, but that amount of current draw implies either a <50% efficiency (which is quite poor for this kind of PSU) or would only occur for abuse/surge scenarios like starting very large motors. Such short-lived inrush events generally won't trip a fuse unless you do something dumb like lock the rotor. And none of that applies to the small microstepping-driver stepper motor systems we're working with here. This PSU should not draw more than 4A in normal 3D printer use.
Looking at this on the other end -- how much damage will 10A do versus 4A? Lots. If the short is in the 12v system, and the PSU's short protection doesn't trip in (because it's a cheap knock-off) you would roughly multiply the AC fuse current times 10 to get the DC current. And 40A is a downright scary amount of current! Depending on wire gauge, putting 40A through heatbed wiring may make it smell and smoke. Whereas putting 100A through heatbed wiring will almost certainly start a fire.
You're much safer with a 4A or even 6A fuse for this PSU than a 10A fuse.
Comment: Should also point out a 1-star review on the switch's Amazon entry that said it melted after an hour at 4.5A... Although it seems like a lot of different switches are sold under this listing. I actually have one of these from this exact Amazon listing  in a printer right now, and the wiring to the onboard switch is very small. I would trust the main terminals to 10A but not the lighted switch part.
Comment: If I'm not mistaken, any fuse you find rated to 125+ will be intended for AC. DC circuits over 24v are pretty rare.
Comment: So another words, with the fuse we're using the fuse to prevent power spikes coming in from the wall outlet that might send too much DC power to the heatbed and electronics and catch them on fire?   So you don't think the switch is safe?
Comment: Most often, the fuse is there to kill power in case there's a short in your mains wiring between the switch and PSU, which may be quite destructive before your home's circuit breaker trips. Or the fuse may trip if the PSU fails and starts drawing excess current. Having an oversized fuse may allow the switch to melt down without tripping any kind of protection.
Comment: MOST of the time, shorts in the printer's wiring will be caught and stopped by the PSU's built-in over-current protection. You shouldn't really rely on that though if you're buying clones rather than name-brand PSUs (like the MeanWell that this PSU is copied from).
Comment: The switch should be fine for 4A, I'm putting around 2.5-3A through it without any issues, but I don't know if I would trust it to 10A.
Comment: Another words don't wire the PSU up to anything that pulls more electricity than the 3D Printer will?  Because the printer only draws about 4A (or is that the PSU?)
Comment: The printer will pull up to 29A at 12V DC from the PSU. I don't know your component specs (particularly the heatbed) so I can't calculate the exact draw. Realistically, you can probably hook up 20-25A worth of load to the PSU and it should be fine. (Depends a bit on the PSU build quality.) THEN, in order to provide up to 29A @ 12VDC to the printer, the PSU will draw up to 4A @ 120VAC from your house wiring. The input and output POWER are the same (less conversion efficiency losses)... but the current and voltage are different.
Comment: If your printer only needs ~15A to run everything, the PSU will only draw ~2A from your house wiring. It's just a converter. It drops voltage and raises current.
Comment: I went to an autoparts store and got a 4A fuse for my switch.  But I think it's DC since it reads 32V on it and there's no spring inside, it doesn't perfectly fit in the fuse cabinet inside the switch.  I was reading that there are AC and DC fuses, so I guess the need an AC one, since the power is coming in from the wall outlet via the switch as AC.  Right?
Comment: You need a fuse rated 125v or higher. If the fuse says 32v, it's probably only rated to 32v.
Comment: And an AC fuse right?


Audit List field level changes - SharePoint

Question: Is it possible to audit changes on List fields in SharePoint 2013? What I'm looking for is to get some report when certain fields in a List is changed by users, not looking for values but just a report on which of the fields were changed?
Answer: There are certain classes defined inside Microsoft.SharePoint namespace which you can use to customize your audit report.

SPAudit
SPAuditEntry
SPAuditEventType
SPAuditQuery

Please look into this URL.It actually tells you about auditing and different levels of auditing in Sharepoint.
http://www.codeproject.com/Articles/431342/Auditing-A-Built-in-Feature-of-SharePoint
Without Server Coding
We can use audit feature of Microsoft SharePoint Server 2013 or SharePoint Online to track which users have taken what actions on the sites, content types, lists, libraries, list items, and library files within your site collections

So in List,Libraries and Sites category you can check the event "Editing Content types and columns to get the columns that have been modified or edited by user"
The audit log captures the following information for the events that are selected to be audited.

Site from which an event originated
Item ID, type, name, and location
User ID associated with the event
Event type, date, time, and source
Action taken on the item

To view Audit log reports
Comment: I was hoping to do this without writing any server side code and just get details of fields names and not values. Not sure if I can do this using a SPD workflow.
Comment: Please see my updated answer
Comment: Hi Amit, appreciate your response. I'm aware of these audit reports which are OOB. What I'm looking for is to identify which fields have changed instead of a list of all activities on a list. The ideal report would display just field names (from my list) that have changed since the item was first created with the modified by value. I could work with the existing SP audit reports to get what I want but it involves quite a bit of work.
Comment: @Manu: interesting question, did you find a solution in the meantime?
Comment: nope, I have not found a solution.