Where can I find indie "teams"

Question: I'm looking to work over the internet in a team of people to make a game. I'm not looking to make a profit, I just want the experiance. Where can I find similary minded persons?
Answer: Personally I don't like working with random people over the internet. Also you will find few games actually succeed without the dynamic of loyalty and accountability that comes with actually having to deal with someone.
If you are a student ask around, I promise there are others interested in the same things as you. If not Google around and try to find a game development meet up in your area. Also there are often groups dedicated to certain technologies (XNA, Unity) if you live in a populate enough area.
If that fails I suggest looking at currently under development opensource games and seeing if they will let you join. Forking it and making a meaning full improvement or fix is a great way to get a team to enthusiastically welcome you.
But just speaking from experience, its near impossible to get any sort of dedication or staying power for a project unless the members and invested in it and each other emotionally.
Anyways that is my 2c. Mostly coming from experience founding modding teams.
Comment: People on the internet usually also have vastly different views on 'religious' topics - very often views of people will align over time; if they know each other in person. It's difficult making a game when everyone wants to do it differently.
Comment: I disagree, I've worked on several mod teams and never had an issue; most of the time they haven't even been local, I've worked across time differences of 12 hours and still had cohesive work flow.
It all depends on the who, and what their motivations are. IMHO these projects don't work unless everyone gets an input. No one wants to be a slave worker; and in most cases, most of the developers aren't unintelligent.
Comment: +1 for finding people in person. Check if your local IGDA chapter has any meetups. Or if you have any other similar organization. For example, NYC has NYCGI and Philadelphia has VGI Philly. Find out if there's going to be a Global Game Jam site in your area.
Comment: addition to @Daniel, that's how i got started too and didn't have any issue. The only issue you have is an asynchronous workflow and hard to meet release dates.
Answer: IndieDB is a good place for indie develoers. They even have a dedicated job section. Paid and unpaid.
For beginners, its easier to start with modding, ModDB. Pick a game your like to mod. Then look for existing mods and see if they need someone of your skill. i.e. Half Life 2.
Also, note what @ClassicThunder said. You said you only want the experience. So, for ONLY experience both of them are a very good place to start. But, very few of them actually get completed. So, prepare for anything!
Answer: I highly recommend going to game jams, where people attempt to make video games in a short time span.  If you are looking for experience in working with others, they are great environments to do so.
I recommend the Global Game Jam, but there are many others.  A place to look for them is CompoHub which is mainly online game jams/contests but also lists local ones as well. Some places have much more of a game development scene than others.

Where can I find indie "teams"


Non-offensive version of the word "mongol"?

Question: I want to describe a person or group of thugs who cause damage without concern for science or culture.  I had written down "mongol behavior", in reference to the Mongol invasion.  Is there an all-culture-friendly word to express a similar concept?
Comment: There's an extra danger with using "Mongol", which is that people might see a connection to "Mongoloid", which was an old word for [someone with Down syndrome](https://en.wikipedia.org/wiki/Mongolian_idiocy). That's definitely not an epithet you want to be using in this enlightened age!
Comment: I wanted to suggest [the Huns](https://en.oxforddictionaries.com/definition/hun) as a stand-in replacement until I realized the word was used as a pejorative blanket term for Germans during WWI and WWII. It seems no matter what historical metaphor you may be tempted to use, it *will* inadvertently target someone innocent, so best avoid it altogether.
Comment: I don't think you can describe *a person or group of thugs who cause damage with no respect to science, or culture* using *an all-culture-friendly word*.
Comment: @LucianSava By "all-culture-friendly" I mean something that doesn't offend a culture.  For example, if I call them "mongols", then some nice people in Mongolia may rightfully say "hey, I'm a nice person".
Comment: Every Mongolian person would say that. If you're concerned about cultural sensitivity, lowercasing anyone's proper name is never the way to go. That said, good on you for realizing it and asking around.
Answer: Note that "thug" comes from a violent religious sect in India, and "vandal" from a Germanic people that ravaged parts of Europe. "Barbarian" refers to uncivilized others, without reference to any specific people, so that may be your best bet.
Comment: @CaptainCodeman: there are no Vandals around today (or at least, no people who call themselves Vandals), so "vandal" is clearly more acceptable.
Comment: @Spagirl Other way round - there's an ancient Greek work 'barbaroi' which means "people who don't speak Greek" (probably because their speech sounds like "bababa", like English "blah blah"), and therefore uncivilized barbarians. Lots of barbarians who vandalised the Greeks came from North Africa, so the name got associated with them.
Comment: Barbarian refers to people from Barbary, the Saracen countries along the north coast of Africa.
Comment: Is it just as acceptable to say "mongol" as it is to say "vandal" ?
Comment: @Spagirl my understanding is that the original  Greek meaning of "barbarian" predates that specific connotation; the word was applied as a sort of back-formation to that region much later.
Answer: Well, as Ms A pointed out, "damag[ing] without concern for science or culture" isn't a sense that (M|m)ongol even has. The Yuan Dynasty was a highpoint of Chinese cosmopolitanism and, even in the west, the Mongols subsidized astronomical advances. Good soldiers tend to love good applied science; scientifically hostile groups tend to be religious zealots like Savonarola. Mongol's only negative connotations come from 19th-century pseudoscience, which mixed up East Asians and people with Downs syndrome.
You just mean barbar(ous|ic|ian), which doesn't derive from any particular ethnicity. It's just a nice latinized form of Greek people making fun of foreigners' speech.
The problem you're going to run into is that any English word referring to groups of people as unenlightened savages is going to have at least 200 years of problematic racist usage. Even the best English word for people overtly hostile to culture, philistine, harkens back to ancient racism we've traditionally considered divinely sanctioned.
Your best woke option is going to be to simply focus on the behavior itself—violent, wanton, reckless, wild, &c.—and not the people as a group. If you don't want to say some cultures are inherently superior, group pejoratives are inherently problematic.
Comment: I am SUPER confused by most of the answers to this question. Regardless of any historical facts to the contrary,  the notion of savage "Mongol hordes" led by Genghis Khan, trampling everything in their path, is a very well-established Western cliché. Captain Codeman's question didn't make me think about "Mongolism" even for a second; rather, I thought he was avoiding the connection to modern-day Mongolia.
Comment: The notion of them being powerful is very well established. The notion of them being noble savages pops up. The notions of them being philistines doesn't and isn't. If you didn't know about that meaning of the word, good on you: it's outdated, wrongheaded, and unpleasant. It is, however, a historical meaning of the word, which has never been synonymous with "philistine" or even "savage", outside of the people of Mongolia itself. As already linked and available elsewhere, if you run into the paywall.
Answer: Forget about the nationality. You say that you are thinking of the "Mongol invasion."
So, instead of using Mongol behaviour, refer to the type of activity and use invasive behaviour:

[Merriam-Webster]
1 : tending to spread especially in a quick or aggressive manner
3 : of, relating to, or characterized by military aggression
Answer: If you want to avoid any cultural bias, mindless morons (she checks etymology of "moron"...) Its safe!

moron (n.)
  1910, medical Latin, "one of the highest class of feeble-minded persons," from Greek (Attic) mōron, neuter of mōros "foolish, dull, sluggish, stupid," a word of uncertain origin. The former connection with Sanskrit murah "idiotic" (see moratorium) is in doubt. Latin morus "foolish" is a loan-word from Greek.

As for the epithets mongol, and mongy, both are derived from mongoloid which used to be the medical term for those afflicted with Down's Syndrome, mongol later became highly derogatory and it is currently used as an insult to anyone whose behaviour or intelligence is considered subnormal or below average. I would advise not to use it, particularly in the context described by the OP, for that reason alone.

In reference to the genetic defect causing mental retardation (mongolism), by 1899, from the typical facial appearance of those who have it. See Down's Syndrome. Such people were called Mongolian from 1866.
Comment: ??? "Mongol" most definitely does not come from "mongolism!"
Comment: In particular, the OED cites _Mongol_ (meaning _A member of any of a number of closely related Asiatic peoples now chiefly inhabiting Mongolia; a Mongolian_) from 1613 but lists J. L. H. Down's use for the the syndrome that later took his name as 1866.
Comment: @Tripehound I believe the reason why "Mongoloid" was originally chosen by Down to describe the syndrome was because of the epicanthic fold in the eye surround, a symptom of the condition - which resembles a similar fold, not just in Mongolians but many oriental peoples.
Comment: @ErnestFriedman-Hill [In it's lowercase form, it most certainly does](http://www.oed.com/view/Entry/121211) (or, in any case, the related pseudoscientific category of "mongoloid").
Comment: Ms A, I think Mr Codeman really was focusing more on the violence or anti-intellectualism than simple idiocy. I guess you were just going for alliteration?
Answer: When looking for insults, it is often useful to fall back on the two greatest insultants in the English canon: Shakespeare, and Captain Haddock.
In particular, some of Haddock's curses which might work:

Abecedarians
Bashi-bazouks
Blackguards
Brigands
Cro-Magnons
Ostrogoths
Ruffians
Savages
Visigoths
Wreckers
Comment: Several of those refer to ethnicities, albeit ones without active antidefamation groups.
Comment: Abecedarian should have the opposite meaning, as it describes certain educators.
Comment: @Davo According to the [Catholic Encyclopedia](https://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/Abecedarians), the Abecedarians were "a sect of Anabaptists who affected an absolute disdain for all human knowledge". Nothing about them smashing anything, though.
Comment: @TomAnderson Thank you, because a definition like the one used in [Merriam Webster](https://www.merriam-webster.com/dictionary/abecedarian) is the only one with which I was previously familiar.


Can we change the text align without moving the position of an object in illustrator?

Question: Is there such an option we can turn on so when we change the text align of an text object the position of this object will not move in Illustrator?
Answer: You can realign the point text with the original. This could be useful if you ever used point text an need a second line below aligned. Do this:

select your text.
hit copy.
realign your text (yes it moves).
paste in front.
align the realigned text with the align tool.
delete the old copy.

Animation 1: This is what the described sequence gets you.
Answer: When we change the text align of an text object of "Point Type" the position of this object will move. In order to avoid this behavior, we have to change the type of the text block to "Area type". Go to "Type" menu and select "Convert to Area Type".
Comment: This should be the accepted answer! As it is a one-time thing.
You could also create a custom shortcut (Ctrl + Shift + T) to toggle the type conversions while changing the text alignment.
Answer: By definition, changing the alignment means move it to align somewhere different.
You can use Area text rather than point text, However, altering alignment will still move text. Left align text will never automatically fall in the same position if you change it to right aligned.
Comment: i think there is a usecase for this kind of stuff. If you only originaly had one line of text and later need text under it right aligned could be a usecase. You could do this by copying the text, changing alignment (and thus let it move), paste in front and align the items then delete the copy.
Answer: Found an easier solution to this problem... Hope this helps some... I had a menu, that got created back to Illustrator from a PDF... once it does this typically it loses some if not all of the text formatting  and some text may even convert to outline - but that's another problem ;)  So In this example I needed to do some simple price changes... the prices if I changed them of course were left aligned and then would be time-consuming it would be to temp them, align them, move them etc.. this saves lots of time...
Another poster was half right... take your text (assuming its point text), click it

Select the text and then click the round dot to the right of the text, this converts to Area type. It may move slightly but no worry...

Next Step change the Paragraph type to the alignment you wanted

And finally, click to change it back to point text

The text will be same exact location, just the alignment of the paragraph has changed.

For a solution to simply move to center little quicker, use the AlignTextFieldCenter script found here http://www.wundes.com/JS4AI/
Answer: Make sure there is no tab or other invisible character after the text, it will change it's behavior when selecting paragraph options, left justify, center or right justify. With a tab after a piece of text it moves the whole text box with no tab, it moves the text inside the box.


My pregnant cat is still nursing her 8 month old kittens

Question: My cat is still nursing her kittens that are 8 months old . She recently became pregnant again and delivered 4 kittens that were stillborn.
Could that be a cause of her still nursing the kittens from her previous litter?
Answer: I am not a cat expert, but with rabbits it would be highly likely to see the kits be stillborn when the mother was still nursing.   There is some related information about rabbits here
Additionally it looks like your 8 month old kittens could be sexual mature, you do not mention having any of the kittens fixed, so it is possible that one of the male kittens was the father of the stillborn kittens.  Inbreeding can be another cause of stillbirth.
The only definitive way to get an answer about why they kittens were stillborn, is by having a veterinarian look at the stillborn kittens.
Related:

How soon after giving birth can a cat be spayed?
How can I get my cat to stop nursing from its mother?
Answer: This is a tough question and something I had actually researched often due to a similar issue. Some queens, like 10% or so, lack vital nutrients and have trouble with birth altogether. My queen Phobos I rescued as an abandoned baby (hypothermic, lethal and wasn't supposed to live) 3 years later she is happy, healthy, but a bit evil lol. She was pregnant 3 times: the first she had 4 stillborns, the second she had 2 and 2 but only one survived the first days, last litter she had 1 stillborn and lost her other 3 in 2 days. I had vets highly involved and we'll kept a nutrition diet and she just isn't meant to have babies, sadly. All the blood work showed nothing wrong.
The veterinarian thinks that she was a malnourished runt and her small badly just isn't capable to carry to full term. The reason her only baby survived is because the others in the litter didn't live inside long enough and made extra room.
If the kittens weren't born alive I don't think the older babies potentially could've taken the nutrients the mother needed, also if the kittens were born healthy the first few days to a week of milk the babies need. That milk cycle is healthy for the baby from the cat eating after birth, etc. It helps the newborns build immunity and has a lot of beneficial effects for them.


Why is the Planck length considered fundamental, but not the Planck mass?

Question: The planck length is considered by many to be a lower bound of the scale where new physics should appear to account for quantum gravity.
The reasoning behind, as far as I understand, is that $l_{P}=\sqrt{\dfrac{\hbar G}{c^3}}$ consists of the fundamental constants of gravity and relativistic quantum mechanics.
By the same argument $m_{P}=\sqrt{\dfrac{\hbar c}{G}}$ should be equally important, no?
What am I missing?
Comment: To make them all *more* "fundamental", $G$ and $k_\mathrm{e}$ should both be normalized to $\frac{1}{4\pi}$.  This, along with normalizing the speed of propagation $c$ to $1$ will result in the characteristic impedance of free space set to $1$ for both EM and gravitational radiation.
Answer: From the perspective of particle physics, you are correct, the Planck length and Planck mass are essentially equivalent concepts: the Planck mass describes a (very high) energy scale ($\sim 10^{19}$ GeV) at which new physics must emerge, just as the Planck length entails a (very short) length scale beyond which we need a new description. If we set $\hbar=c=1$ (which are really just conversion factors between units) we see that they are inverses of each other, $m_P=1/l_P$.
More precisely, if we take the Einstein-Hilbert action for gravity and expand around a flat metric $g_{\mu\nu} = \eta_{\mu\nu} + h_{\mu\nu}$, where we can interpret $h_{\mu\nu}$ as the graviton field, the resulting action will have an infinite number of higher order terms suppressed by powers of the Planck mass. Roughly, we have
$$\mathcal{L}_{EH} \sim \frac{1}{2} \partial h\partial h+ \frac{1}{m_P} h\partial h \partial h + \frac{1}{m_P^2} h^2\partial h \partial h + \ldots $$
(as well as terms from higher derivative corrections, which are also higher order in $1/m_P$). So we have predictive control at energies scales much less than $m_P$, where the infinite number of higher order terms can be ignored. But once we reach the Planck scale (i.e. energy scales of $m_P$ or length scales of $l_P$) the non-renormalizable effects become important and all the quantum corrections and higher order terms render the above Lagrangian equation useless, and we require a new description.
Comment: The Planck mass does not in itself need a new physics (plenty of living creatures are larger and many others are smaller).  But a black hole with the Planck mass may need a new physics.
Comment: @4xion did I correct that typo correctly? unless -> useless
Comment: What creature is smaller than a Planck length
Comment: @Rick not the Planck length, but the Planck mass (~10^19u)
Comment: @Henry Such a mass is spread out over a huge distance (on the scales relevant for particle physics). But you're missing the point, the electrons, photons, etc all around you are usually interacting at energies far far below the Planck scale. But once you consider interactions at these high energies, you'll need new physics.
Comment: 4xion You are saying that a Planck mass concentrated at a single point (or within a Planck length to meet @Rick's question) needs new physics; I do not disagree, but that is not a question of mass alone but one of density.  Similarly it is easy enough to have explosions orders of magnitude larger or smaller than the Planck energy, but you only need new physics when this is sufficiently concentrated.
Comment: I don't disagree, I just think thinking about concentration is a bit misleading, especially in QFT where we have interactions which are local and point-like. It's the energy of these local interactions that's important. The energies of the explosions you mention are just summing up lots of interactions at very low energies (compared to the Planck scale), which is not really what we mean by Planck scale physics. But I do agree that the idea of a local interaction is problematic at high energies
Comment: It's also maybe worth mentioning that the above Lagrangian also breaks down at very large gravitational field values of $h$, which is just the statement that you need a new description in extremely high curvature regimes (e.g. for those in a black hole)
Comment: @BobStein re typo: good catch, thanks!
Answer: The Planck mass makes the units work out "nicely" in a lot of equations, sort of like radians are a very "natural" unit of angle measure, or $e \approx 2.71828...$ is a very "natural" base for exponential functions and logarithms.
But size-wise, the Planck mass isn't anything special. Wikipedia says a flea egg weighs about one Planck mass; so, it is possible to have masses much smaller than the Planck mass.
Mass isn't "quantized" in the sense that every object has mass an integer multiple of the Planck mass, the way electric charge is "quantized" in the sense that every object has electric charge an integer multiple of the charge on an electron (or, if you prefer, the charge on a quark).
Comment: Seems not quite right to say that $m_p$ isn't anything special as it corresponds to the scale at which the non-renormalizable nature of gravity becomes important. Another minor comment: electric charge *appears* quantized but (unless we observe monopoles) there's no guarantee of this.
Comment: @4xion Right, I'm using "special" in the narrow sense of "not a unit of quantization" here. My impression is also that the change in physics from mass scales above the Planck mass to below the Planck mass is far less drastic than the change in physics from length scales above the Planck length to below the Planck length.
Answer: You haven't understood the concepts here quite right I think. It is not that ordinary physics cannot describe things happening over small distances (Planck length for example), it is rather a question of interaction energies between point-like entities such as quarks and electrons. Even Newtonian physics can describe an ordinary ball moving through a distance of one Planck length. But if a process is characterised in its dynamics by very short distances, then quantum theory will be needed.
The Planck mass is important in that if the collision energy between point-like particles is of order one Planck mass multiplied by $c^2$, then we need a quantum gravity type of theory to describe the process.


Is it possible to show that this subset of reals has properties of natural numbers?

Question: So I heard of the following way to define naturals in real numbers.
Let's call a subset $A$ of reals to be inductive if and only if:
1)it contains $0$.
2)it contains $k+1$ whenever it contains $k$.
Than, we define real number to be natural if it is contained in every inductive set.
Now, can we show that set of all natural real numbers is closed under addition and multiplication, and that $0$ is least element (with real number ordering) ? Or maybe it is possible to prove this properties with other definition of naturals in reals ?
Answer: Let $\mathbb N$ denote the set of elements that are contained in every inductive subset of $\mathbb R$.
It is immediate that $0\in\mathbb N$ and further the set $[0,\infty)$ is inductive so that $\mathbb N\subseteq[0,\infty)$, showing that $0$ serves as least element of $\mathbb N$.
Now define: $$K:=\{n\in\mathbb N\mid \forall k\in\mathbb N[n+k,nk\in\mathbb N]\}$$and prove that $K$ is inductive.
Then $\mathbb N\subseteq K\subseteq\mathbb N$ so that $\mathbb N=K$, and you are ready.
Comment: Sorry, I am not familiar with this notation $\mathhbb N[n+k,nk\in\mathhbb N]$. Maybe you can call it's name, so I can find it in the internet.
Comment: In words $K$ is by definition the subset of $\mathbb N$ that contains exactly the elements $n\in\mathbb N$ that satisfy $n+k\in\mathbb N$ and $nk\in\mathbb N$ for every $k\in\mathbb N$.
Comment: So could it be written in the form $$K:=\{n\in\mathbb N\mid \forall k\in\mathbb N,n+k,nk\in\mathbb N,\}$$ ?
Comment: Something like that , yes. $\mathbb N[n+k,nk\in nk\in\mathbb N]$ is not a notation on its own.as you seemed to think.


Export org-mode blocks to a text file

Question: Is there a way to export the contents of org-mode blocks to a text file? The blocks will contain only ascii text.
I can export the contents of a source block using Babel with tangling:
#+BEGIN_SRC  latex :tangle yes
Export this text to a text file.
#+END_SRC

However, this produces a file of type specified by the language identifier. The language identifier in the example above is latex and therefore the output is a .latex file. Is there a way to export a block to a .txt file?
Update:
matteol's solution works. However, the output file will be named out.text. It seems Babel takes the suffix from the language identifier in the header, so replacing text with txt will produce out.txt.
If you want to send the output to a .txt file with the same filename as the source org file, here is a working example:
#+BEGIN_SRC txt :tangle yes
Export this text to a .txt file.
#+END_SRC

For example if your source file is named my_document.org, the tangled output file will be named my_document.txt.
Because it is possible to export text in the way described, it might be helpful to update the Babel language documentation to reflect this. I don't see an option for txt in list of supported languages.
Answer: You can specify a file name in the :tangle header argument like this
#+BEGIN_SRC text :tangle out.txt
Export this text to a text file.
#+END_SRC

See the manual for details

Export org-mode blocks to a text file


What is "offset null" in IC 741?

Question: What is Offset null in 1st and 5th pin in IC 741 (Op-Amp)? Why it is used, though it is not used in many circuits? Give me explanation regarding the offset null!
Why offset voltage was formed in IC 741?
Comment: What they all say BUT do not use a 741. Use an LM324 or some even better more modern opamp.  Offset voltages occur because the manufacturing processes are not perfect and there are small differences which combine to look like a single input voltage rror. They may be distributed through the IC but can be represented by and corrected by an  offset voltage.
Comment: I think that the question is a bit upside down. It'd be more insightful, I think, to ask why there would be no offset voltage. Once you pose the question that way, you can realize that perhaps physical objects can't ever be perfect, so it'd be rather unexpected to assume that one particular physical object - an operating amplifier - would be somehow exempt from the rules that affect everything else in Nature. As to why exactly an op-amp has input offset: the input circuitry isn't perfectly symmetric, in various ways.
Comment: I found this question because I wondered how to use the null on the 741--the TI Datasheet at https://www.ti.com/lit/ds/symlink/lm741.pdf doesn't say how to use the offset null inputs.  Some general refs say you bridge across the nulling inputs of op amps with a pot with it's wiper at 0V and others at V-.  Frost's answer at https://electronics.stackexchange.com/a/55875/30711 says it's to V- and gives a pot value.
Answer: The datasheet gives an example.

By adjusting the pot we can null any offset error. An offset error is when the inputs are exactly equal but the output isn't exactly zero. This error is also characterized by the datasheet:

It can be safely ignored in AC applications, where this offset will be ignored by the AC coupling. It becomes more important in DC applications, especially amplifiers, since this DC error will be amplified by the next stage.
This offset voltage exists because a real omp-amp can't be ideal. There will always be some unintended asymmetries between due to random variation in manufacturing. In all cases, there are op-amp designs that can minimize these errors, but usually at the expense of some other parameter, like cost.
Comment: Just to clarify, it's not correct that an op-amp with infinite gain would as a result have no offset voltage; non-infinite gain and non-zero offset are independent deviations from the ideal op-amp model. An op-amp with non-zero offset and infinite gain, in a negative feedback configuration, will simply drive it's output to the point that the two inputs differ by the offset voltage, which is likely to cause an error at the output relative to the desired output.
Comment: @AbiRAM02 because nothing is perfect. An ideal op-amp has no offset because its gain is infinite, there are no leakage currents, and there's no undesired impedance anywhere. Any _real_ op-amp will necessarily have these things, the 741 being no exception.
Comment: why off set voltage is produced in IC 741 ?
Comment: @ThePhoton: To clarify further, an infinite gain op amp may have input offset, output offset, or both.  If an op amp has an input offset of X and output offset Y, the output will be voltage Y away from the point where the inputs would be voltage X away from each other.
Comment: ,It's good,Can you explain me,What is the reason behind presence of off set voltage..?
Comment: AbiR: He just did.  Offset voltage is a undesirable but inevitable result of building any real opamp.  Transistors and other parts are never matched perfectly.
Answer: For circuits that accuracy and/or symmetry is critical, the offset null pins provide a means to cancel "internal" discrepancies. The best example I can give you is the old ohmmeter. You would short the leads and adjust the needle to read zero, then you knew your resistance readings would be as accurate as possible.  With the 741, you provide the same voltage (signal) to the input pins and adjust the offset null to make sure the output is zero.
Answer: as ics are manufactured with cascade amplifiers,a smal voltage is enough for its workng n as semiconductors are used the room temperature is enough to get extra voltage so while operating using opamp,offset nul is connected so as to make these voltages zero

What is "offset null" in IC 741?


Did Java invent interfaces?

Question: I know about C++ pure virtual classes, but Java went one step further and created a first-class (no pun intended) concept for multiple-interface (not implementation) inheritance, the interface. It's now a staple of major statically-typed languages. Did Java invent the interface concept? Or did it appear in older languages also as a first-class concept?
Comment: Did Java's designers really invent anything? AFAIK, they simply brought together a bunch of ideas that had been sloshing around for quite sometime prior to the language's inception.
Comment: @Neil: true, but that's how most non-academic languages were created.
Comment: @Trevor Tippins Why did you delete your answer? It's fully legitimate.
Comment: @Joachim Yes, I wasn't intending a criticism.
Comment: @Neil Butterworth: Statically checked exceptions.
Comment: @Tom A good idea? Anyway I'd need some evidence that Java invented that - wasn't Ada doing something similar long ago?
Answer: Here is abstract from the article The Java Language Environment.
An interface in the Java language is simply a specification of methods that an object declares it implements. An interface does not include instance variables or implementation code--only declarations of constants and methods. The concept of an interface in the Java language was borrowed from the Objective-C concept of a protocol.
http://java.sun.com/docs/white/langenv/Object.doc2.html#6185
Answer: As far as I know Objective-C was the first language to feature interfaces. At least it had them before Java was invented.
Comment: Of course, but the 'interface' concept is called 'protocol' in Objective-C.
Comment: I don't know Objective-C, but by its wikipedia entry, it seems that its `interface` is more related to a forward declaration of a specific class interface (like a C++ header file), and not to the Java interface concept. Please correct me if I'm wrong!
Answer: I'm pretty sure IUnknown and IDispatch existed before Java... But that's COM, which isn't really a language.
Answer: pure virtual classes without fields were called in C++ interfaces even before Java. Idea behind Java's interfaces was to remove nasty multiple inheritance as it was in C++, but leave similar capabilities.
Answer: I'm quite sure that Java developers didn't invent the concept of interfaces but they popularize them.
Answer: IDL, used by CORBA, I believe goes back to the early 80's.
Comment: @Jordão IDL is not a programming language. It is however a language (that is the L bit).
Comment: Yes, but IDL is not part of a language, but of a specification for language interoperation. But you're right, it might have influenced the Java interface concept in some capacity.
Answer: I love interfaces but I am just at the beginning of learning how to use them. The most flexible and powerful interface system that exists in a programming language is in Go, but as people pointed out, Java popularised them but they existed 20 years ago, I wish I could remember the language I found the other day, starts with 'g' I think, maybe something about a mineral or flower in the name.
The central principle of interfaces is about creating descriptions of things around how they pass values between. They create a way to pass a chunk of data with some set of uses to another form with a very close set of uses. Interfaces usually use a naming scheme to indicate that the interface definition pivots around the abstract commonality between several things. In programming, everything boils down to bytes, so you can build interfaces around sharing bytes, there is always some common feature.
In a practical sense, an interface is a set of methods surrounding a data type that you haven't specified, except vaguely. Go will teach you good about interfaces. Interfaces appear most prominently in the most object oriented language, as the OP, java, but as far as I know, Go has the most powerful interface system. Go is statically typed, but interface types make no constraints on data, in Go. Only the limitations you define by the types the interface can pass.
I am just starting to learn how to program in Go with interfaces, but a lot of the wisdom gained by the Go programmers' experience is helpful with anyone interested in interfaces. Interfaces need to be compact and functional. Very often, you don't need to define an interface because the data is just too different. Maybe for storage and transmission, all data === all data. This is what interfaces are for. Two different systems, what data structures do they share. This is exactly what an interface is.

Did Java invent interfaces?


What is the resistance of an electric arc between two graphite electrodes?

Question: I want to make a mini arc furnace just for fun. I have two 4mm diameter graphite electrodes from an AA battery. I could calculate the loss of heat by radiation, but I dont know the resistance of the arc and I need it to calculate the windings of the transformer that will supply it since I dont have a power source with more than 10 A.
Comment: Datapoint only: With a 30Vmp 300W solar panel I can draw and hold an arc in full sun. Not a large arc, but impressive that it can be done. And salutary when considering DC switching.
Comment: I can't stand behind this as an answer, but another forum has a discussion on this topic here: https://www.physicsforums.com/threads/what-is-impeadence-of-ionized-air.141338/ . I think you want to know what the minimum resistance is (for the voltage or current you apply, depending on whether your application is limited by voltage or current). Or maybe you want to know the average resistance during arc if the system oscillates very fast. Also, please add to the question what is the voltage of your power supply, so someone can better tell you possible/impossible right away.
Answer: Arc lamps have a negative resistance characteristic, so they need some series impedance to stabilize them if you are planning on connecting them to a voltage source.
You can experiment with something like a 500~1500W (at the supply voltage) heating element such as a small room heater in series with the electrodes. You need a way of  (safely) bringing the rods into contact and then separating them when the carbon gets hot enough to sustain an arc.
As a WAG I would say the resistance in normal operation is around 5~10 ohms, but has a negative slope so a series resistance of perhaps 10~20 ohms will stabilize the arc and control the current to something reasonable for the size of the rods.
It cannot be emphasized too strongly that there are many ways to hurt yourself playing around with this- the voltages on the rods are usually high enough to be lethal (perhaps with respect to ground if you're trying to use mains without an isolation transformer- not recommended) and the arc will likely emit strong UV light- that's why they were used in the old plate making machines for offset printing (now replaced by sealed mercury arc lamps).
Check out the venerable Don Klipstein's page for more info.
Answer: I've been in an electric arc steel mill as this is happening, and a real one requires thousands of amps, enough to power a small town.  It works by conducting current through scrap metal until it heats up enough till it melts, and then the liquid steel becomes part of the circuit, not the actual arc radiating.  You need a ton of power to convert steel from a solid state into a liquid state.
To put it in perspective, consider a stick welder from Lincoln electric which can melt the tip of a welding rod.  It uses about 80 amps just for melting the tip of some 3/32" carbon steel rod.  So, with a paltry 10 amps, don't expect too much to happen.
That being said, for experimental purposes, to see what you can accomplish with 4 amps, a high school experiment I've seen was to attach leads from a small battery to steel wool.  Wear safety gear of course.  Basically it will glow red hot and then oxidize before your eyes.


Flex - How can we measure the height of a control with nested renders?

Question: I'm using a List control.
In the renderer of the List control I've got a Repeater.
Each Repeater can have a different number of items.
Adding to the complexity, one of the components being repeated in the
repeater is a Text control that has long text that will wrap,
increasing it's height.
I need to expand the height of the List completely so that there's no
vertical scrollbar.
How can I do this?
I tried an extremely dirty attempt at calculating the Lists height
based on the data source. From the data source I can figure out the
number of repeater items and the number of items in each repeater in
the List's renderer. But there's no way to compensate for the wrapping
of the text in the Text control.
Is there a better way (or any way!) to do this? Please help.
Thanks in advance,
zxcvb
Answer: This method might help measureHeightOfItems()


How do I detect the signal and ground wire on a bluetooth earphone cable?

Question: I have a wireless bluetooth earphone, on which the left driver plays at half volume. I want to cut off the drivers and solder in a mmcx connector so that I can have options on the drivers. However assuming the color coding isn't standard or nonexistent, how do I detect the ground and signal wires without an option of doing a continuity test against 3.5mm jack ?
Answer: There may not be a ground if the drivers operate fully bridged (wikipedia: h-bridge).
A shorted transistor on a h-bridge leg would also nicely explain a half volume output level.
Comment: so how to ensure the new connection won't make drivers play out of phase ? The electronics and battery are pretty well sealed, and me clumsily cracking them open might compromise the sweatproofing.


How can I include Dresden-Files-style vampires in my Pathfinder game?

Question: I have a concept for a campaign that uses a Dresden-Files environment in a medieval fantasy setting, but for reasons of familiarity and experience prefer to use the Pathfinder system. I specifically need to be able to create stat-blocks for the vampires. I'm not sure I understand the vampire system well enough to create them myself. I understand there is a Dresden-Files RPG, and I don't know of any conversion techniques for Dresden stat block -> Pathfinder stat block. My player characters are built according to standard Pathfinder rules, it's only the monster blocks that need creating.
Answer: The Dresden Files is a different paradigm in RPGs than Pathfinder.  The concept of statistics doesn't enter into the picture.  What you would probably want to do is to take a vampire in Pathfinder, then take the spirit of the Vampires of the Courts in Dresden.
Black Court Vampires (OW85) would do very well as standard Pathfinder vampires; from the Dresden Files, these are the standard vampire that we usually think of.
Red Court Vampires (OW88) would be similar; I'd keep the Energy Drain, Blood Drain, Create Spawn, and Change Shape (but only to a Dire Bat) abilities, and the weakness to Sunlight and Holy Things, but remove the other special attacks and qualities.  In place of those, the addictive saliva (which would be a variant on dominate), and the vulnerability in the stomach would have to be modeled.
@JonathanHobbs suggested in the comments that a slightly increased critical range might be good for modeling the vulnerability in the stomach.  I like that approach, though @CRoss suggested a reduction in the natural armor that vampires receive.
White Court Vampires (OW90) would be a bit more tricky.  Keep Energy Drain, and feeding would have to be altered to be based on that.  All other special attacks and qualities are invalid- other than a variant on Dominate to emulate the incite emotion.  Their Energy Drain would be dependent on the victim being under that effect.  Their only drawback would be the vulnerability to emotion.
For the Raiths, for an example, I'd probably use Charm Person and/or Enthrall, one to represent the attention of the Vampire on one target; the other one their ability to affect a crowd by their presence.  Honeyed Tongue might also be appropriate, as the more subtle effect probably better represents their influence.
There are other tweaks- but they won't be direct conversions; the systems just don't lend themselves to that IMO.  Just keep the spirit of the vampire, while modeling off of the pathfinder version.
Comment: You could make certain abilities only available to vampires after aging, or you could just say that as they get older, they get more experienced- or a combination of the two.  That would be by preference.
Comment: I'd recommend adding NPC levels.  The powers of older Dresden vampires are depicted as being quite variable and individual... The Red King's an evil priest, Mavra's a wizard, Lara's a warrior / noble, and most tellingly, Ortega's a warrior but his wife's a wizard.
Comment: What if I'd like different "ages" of vampire? Should that just be NPC levels on top of whatever template we can create?
Comment: Since the Black Court is the Bram Stoker vampire and in Pathfinder that's the [Nosferatu](http://www.d20pfsrd.com/bestiary/monster-listings/templates/nosferatu), perhaps that would be a better equivalence than the standard PF vampire?
Comment: @SevenSidedDie - It could, as a matter of choice be used- I guess what sways me that you're possibly right is the fact that they are a dying breed, as is the Black Court.
Answer: As mentioned above, Black Court are pretty close to the standard vampire.
Red Court need blood to get powerful but you can kill them by puncturing their stomachs to spill their blood, so maybe give them a bonus after feeding or a bonus that's based on their current HP?
White Courts are meant to play on the succubus myths more than the vampire myths, so you might use a succubus with the spell-like abilities and shapeshifting trimmed off.


Pushforward of semi-stable sheaves under finite field extension

Question: Let $k$ be a field of characteristic zero and $X$ be a non-singular rationally connected variety over $k$. Let $L$ be a finite field extension of $k$. This induces a proper morphism $p:X_L \to X_k$. Is it true that for any torsion-free semi-stable sheaf $E$ on $X_L$, the coherent sheaf $p_*E$ is semi-stable on $X_k$?
Comment: What definition of semistability are you using?  If $p_*E$ is destabilized by $F$, i.e., some appropriate slope of $F$ is greater than the slope of $p_*F$, then presumably the same holds for $p^*F$ and $p^*p_*E$.  Since $p^*p_*E$ is $E\otimes_L(L\otimes_k L) \cong E^{\oplus n}$ for $n=[L:k]$, this would seem to contradict semistability of $E$.
Comment: @JasonStarr: your comment and my answer are virtually identical. However, $L \otimes_k L \cong L^{[L:k]}$ only holds if $k \subseteq L$ is Galois. Otherwise, you first have to pass to the Galois closure of $L/k$ (or, as I do, all the way to $\bar k$).
Comment: @R.vanDobbendeBruyn.  I absolutely agree that as a (left or right) $L$-algebra, the tensor product $L\otimes_k L$ is not always isomorphic to the product algebra $L\times \dots \times L$.  However, as a (left or right) $L$-module, the tensor product is a vector space of dimension $n$.  I believe that is what is relevant here.  Are you saying that the $L$-module structure gets shifted through $L\otimes_k L$, so that the algebra structure is relevant?
Comment: @JasonStarr: Sorry, I misread your argument and gave the wrong objection. I think $p^* p_* E$ is not $E \otimes_L (L \otimes_k L)$, but rather $E_k \otimes_k L$ (where $E_k$ forgets the $L$-structure). I see no way of relating the two (over $L$), and in fact I don't think that they are the same. For example, if $X$ is an elliptic curve over $\mathbb R$ and $E = \mathcal O(P)$ for a non-real point $P$, then $p^* p_* E$ should be $\mathcal O(P) \oplus \mathcal O(\bar P)$, which is not isomorphic to $E^2$.
Comment: @R.vanDobbendeBruyn.  For a Cartesian square of schemes, say $f:X\to Z$, $g:Y\to Z$ and $f':W\to Y$ and $g':W\to X$, if $f$ is quasi-compact and quasi-separated, and if $g$ is flat, then for every quasi-coherent $\mathcal{O}_X$-module $E$, the natural map $g^*f_*E \to (f')_*(g')^*E$ is an isomorphism.  For $f$ and $g$ both equal to $\text{Spec}(L)\to \text{Spec}(k)$, it follows that $g^*f_*E$ is the same as the pushforward of the pullback of $E$.  Thus, for every scheme $T$ over $\text{Spec}(L)$, for every quasi-coherent sheaf $E$ on $T$, $g^*f_*E$ equals $(L\otimes_k L)\otimes_L E$.
Comment: Having said that, the $L$-module structure is through the left $L$-action on $L\otimes_k L$.  Thus, if $T$ equals $S_k$, then the $\mathcal{O}_{S_k}$-module structure is unambiguous, but the $L\otimes_k \mathcal{O}_{S_k}$-structure of $(L\otimes_k L)\otimes_L E$ gets "shifted".
Comment: @JasonStarr Does this mean that the answer is correct?
Comment: @user43198.  "Does this mean that the answer is correct?"  Yes, Remy's answer is certainly correct.
Comment: @JasonStarr Doesn't this imply that a non-empty moduli space $M_X(P)$ parametrizing semi-stable sheaves on $X$ with Hilbert polynomial $P$, will always have a $k$-rational point? In particular, if I understand correctly, the moduli space being non-empty implies that there exists a finite extension $L$ of $k$ such that there exists a semi-stable sheaf $E$ on $X_L$ with Hilbert polynomial $P$. Then, Remy's argument implies that $p_*E$ is semi-stable on $X$, which will give a $k$-rational point. Am I missing something?
Answer: Assuming what you mean is that $X$ is projective and $\mathcal E$ is Gieseker-semistable, the answer is yes.

Lemma. Let $X$ be a projective $k$-scheme, and let $\mathcal E$ be a semistable sheaf on $X$. Then $\mathcal E_{\bar k}$ is semistable on $X_{\bar k}$.

Proof. Let $\mathcal F \subseteq \mathcal E_{\bar k}$ be a proper nonzero subsheaf, and assume that $\mu(\mathcal F) > \mu(\mathcal E)$. Then $\mathcal F$ is defined over some finite extension $k \subseteq \ell$. Let $p \colon X_\ell \to X$ be the projection. Then $p_* \mathcal F \subseteq p_* \mathcal E_\ell$ is a subsheaf, with $\mu(p_*\mathcal F) > \mu(p_* \mathcal E_\ell)$. But $p_* \mathcal E_\ell = p_* p^* \mathcal E = \mathcal E^{[\ell:k]}$ is semistable, so such subsheaves cannot exist. $\square$
Remark. The same statement with semistable replaced by stable is false. See for example this post.
Remark. Conversely, it follows from uniqueness of the Harder–Narasimhan filtration that if $\mathcal E_{\bar k}$ is semistable, then so is $\mathcal E$. Indeed, uniqueness of the HN filtration implies (using the lemma above) that it commutes with base change of the field.

Corollary. Let $X$ be a projective $k$-scheme, let $k\subseteq \ell$ be a finite separable extension, and let $\mathcal E$ be a semistable sheaf on $X_\ell$. Then $p_* \mathcal E$ is semistable.

Proof. By the remark, it suffices to show that $(p_* \mathcal E)_{\bar k}$ is semistable. Because $\ell \otimes_k \bar k \cong \bar k^{[\ell:k]}$, the base change of $p \colon X_\ell \to X$ to $\bar k$ looks like
$$p_{\bar k} \colon \coprod_{\sigma \colon \ell \to \bar k} X_{\bar k} \to X_{\bar k}.$$
By the lemma above, the base change $\mathcal E_{\bar \ell}$ is semistable. Under $p_{\bar k}$, we are merely taking the sum of the Galois conjugates of $\mathcal E_{\bar \ell}$. It is straightforward to check that each of these Galois conjugates is semistable of the same slope, hence their sum is semistable. $\square$
Comment: Doesn't this imply that a non-empty moduli space $M_X(P)$ parametrizing semi-stable sheaves on $X$ with Hilbert polynomial $P$, will always have a $k$-rational point? In particular, if I understand correctly, the moduli space being non-empty implies that there exists a finite extension $L$ of $k$ such that there exists a semi-stable sheaf $E$ on $X_L$ with Hilbert polynomial $P$. Then, by your  argument, we have  that $p_∗E$ is semi-stable on $X$, which will give a $k$-rational point of $M_X(P)$. Am I missing something?
Comment: @user43198: the pushforward will not have the same Hilbert polynomial. Its rank is multiplied by $[\ell:k]$ under pushforward.


Wouldn't residual connections in RNNs solve the vanishing/exploding gradient problem?

Question: I was recently brushing up on my deep-learning basics and came back to RNNs.  LSTMs/GRUs and the Transformer architecture were invented to solve RNN's vanishing/exploding gradient problem. I was at the time also interested in image processing and the ResNet model, so I immediately thought of incorporating the residual connection into RNNs. The idea is to connect the hidden states after each block (skipping the network and activations) to allow for better training of the past blocks. Given that nobody has done this yet, I feel the idea is somehow flawed and not as genius as my mind thinks. Why would/wouldn't this work? Where did I make a mistake?
Answer: In my opinion your idea indeed holds merit. Something worth noting though is that it is cruder than the LSTM/GRU that have trainable weights that guide what features are remembered and forgotten. There are also other architectures than ResNet that uses residuals, but add gate layers to guide what is passed on.
The main thing your idea would bring is likely speed, rather than accuracy. And that is not always a bad thing.
Here are some papers where the author uses a residuals in combination with LSTM:
Residual LSTM
Highway-LSTM
Answer: Your idea is exactly the idea behind state-space models. They have a linear "residual" connection from previous hidden states, skipping activations. In fact, it works very well! I'd recommend reading the Mamba paper. They get comparable results to "transformers" while being several times more efficient, and fixing the context-length issue.
There are two major issues with LSTMs, and in general RNNs, that make training slow:

Vanishing gradients (as you mentioned), and
Only being able to train one token in a sequence at once.

Because state-space models just have a linear "residual" connection, they can train an entire sequence of tokens at once with a parallel scan algorithm (similar to the prefix sum algorithm). Note that this ability to crunch huge amounts of data is what allowed "transformers" to take off.
The issue you mentioned is actually a little broader: if you run an RNN too long the outputs will either vanish or explode. You can imagine a purely linear model, $x\mapsto Ax$, which after $n$ steps will become $A^{n}x$. If the eigenvalues are too big, things explode, while if they are too small, $A^{n}x\to 0$. The authors of Mamba considered forcing $A$ to be unitary (eigenvalues have magnitude exactly one, see section B.3), and mention that other authors have explored it in more depth to resolve this issue.


"A secretary had to call all the clients in her company" probably an easy problem that I am really struggling for some reason.

Question: "A secretary had to call all the clients of her company. By the morning she made 1/3 of the calls; in the afternoon she made 3/5 of the calls that were left and at night called the last 64 clients. With how many clients did she talk in the morning?"
The answer is 80, but I really don't know how to get to it. I took it from a contest that happens in my country so, I had to translate the problem.
One of the things that I tried was x = 1x/3 + 3x/5 + 64, but I got nowhere. This is driving me insane.
Comment: For some basic information about writing mathematics at this site see, *e.g.*, [basic help on mathjax notation](/help/notation), [mathjax tutorial and quick reference](//math.meta.stackexchange.com/q/5020), [main meta site math tutorial](//meta.stackexchange.com/a/70559) and [equation editing how-to](//math.meta.stackexchange.com/q/1773).
Answer: Let the total number of calls be $x$.
Morning: $\frac{1}{3}x$, afternoon: $\frac{3}{5}(x-\frac{1}{3}x)$ (because it is the left over ones), night:$64$.
So we have $x=\frac{1}{3}x+\frac{3}{5}(x-\frac{1}{3}x)+64$. Now solve for $x$, which should be $240$ and so the morning calls is $80$.
In short you got the afternoon one wrong because you were considering $\frac{3}{5}$ of the total call, not the left over ones.
Answer: I like to work backwards.  At the end, she called 64 clients.  Just before that, she called ⅗ of those that were left, so 64 must have been ⅖ of those.  So before the afternoon calls, there were 64 ÷ ⅖ = 160 clients.  And before that, she called ⅓ of the clients, so 160 must have been ⅔ of those.  So before the morning calls, there were 160 ÷ ⅔ = 240 clients.  Now we're back at the beginning, so we know that she started with 240, and we can figure out anything else more straightforwardly.  (In particular, the morning calls were ⅓ of 240, which is 80.)


A potentially dangerous Request.Form value was detected from the client

Question: I'm getting the above exception when I'm trying to submit a form in ASP.NET.
This post was really helpful but even after setting ValidateRequest="false" I get this error only for "&#" combination. This specific combination is required since we are using Norwegian characters.
And I have set httpRuntime requestValidationMode="2.0" in web.config as well.
Comment: is working to me fine, and not get errors even when I send this characters. Maybe you make some redirect and you do not have place the validaterequest to all page. Better try to add it to web.config.
Comment: Yes you were correct. It works when I add it to web.config
Answer: Ok, from the comments, I make it also as an answer.
Place the ValidateRequest="false" on the web.config to prevent the case that its hit on a forgotten page with out this declaration.
<pages validateRequest="false" ... >

Comment: This worked for me, and you along with this you should have httpRuntime requestValidationMode="2.0" in web.config file.


Seeing apps on multiple iPhones

Question: My family has 3 iPhone 5's and we share one iTunes account.  We sync on 2 different computers.  I do not want all the same apps on my phone.  Can I delete them from my phone without it deleting them without screwing up the other 2 phones?
Answer: Yes - deleting an app from any device will not remove it from other devices.
Only if you:

Delete the app from iTunes
Sync more than one device to iTunes
Bypass the warning that an app is present on the device but not iTunes and skip the chance to import that app back into iTunes

will the deletion of an app in one place cascade over to other devices. You might also want to review which devices automatically download apps so that you don't get apps that are purchased and intended for another device.
Answer: Also, be sure to disable automatic App downloads on your iPhone by going to Settings > iTunes & App Store. This way if someone from your family buys an app on their iPhone, it will not automatically download to your iPhone.

Seeing apps on multiple iPhones


Why did the demolition time for Dr. Lanning's house change?

Question: The demolition time for Dr. Lanning's house was set for the next day, and only changed after Spooner when into the house. I believe VIKI was aware that Spooner was investigating Lanning's death, so it would be logical to assume Spooner would eventually go to Lanning's house. So, did she move the time up in case Spooner was getting close, and he just happened to be in the house when she changed the demolition time? Or, did VIKI purposely activate the demo bot while Spooner was there in order to kill him? What was the motivation for changing the demolition time?
Comment: I think it should be fairly obvious she wanted to kill him.
Answer: VIKI was trying to kill Spooner.  The surveillance system at the house was active; Spooner was shown seated at Lanning's desk looking up at the surveillance strip shortly before the demolition robot started ripping into the house.  It was established later that Lanning had linked his home system to USR, so VIKI had access to the surveillance footage and could see Spooner in the house.
Answer: VIKI wanted to kill Spooner. He was getting closer to be aware that she was behind it all and that robots would take over control.


How can I reduce a collection to one node when using arrays

Question: I have a model of a dock which includes the dock, building, bench, bike rack etc and also a row of tires along the edge of the dock made from a single tire and then applying an array modifier so that there are multiple tires along the edge of the dock. When I attempt to reduce the collection to a single node (select All, Ctrl J) the array disappear and I am left with a single tire. What do I need to do to overcome this?
Comment: When you Ctrl-J join meshes in a single object, they all acquire the modifiers of the active    (title) object. BTW, a quick way to apply all modifiers to an object is to _Convert_ it to its own type.
Comment: this should not happen and i am pretty sure you making something more....Can u provide your blend file? this only happens if you did not apply your array modifier...
Comment: maybe there is another array modifier you did not apply?
Comment: Thanks Chris. Firstly I cannot remember how to attach a file. Secondly and most importantly I don't think I have ever 'applied' an array modifier. What I did was to import a model of a tire, select it, then select 'add modifier', then select array and then enter relevant values in the 'count' (fixed count), enter a constant offset value for X and that is all. Is there something else I need to do to apply it?
Comment: because you wrote "applying an array modifier" i thought you had done what i wrote in my answer. But it looks like you just added an array modifier.
Answer: To apply a modifier you have to press this little icon
and then choose apply. If you then tap CTRL J to join it should work.

You can provide your blend file by opening https://blend-exchange.com/ and then follow instructions.
Comment: I have no experience with releasing as freeware but yes, it would it make more difficult to "reuse" your model by others. But not impossible. But just as an example: if the meshes are separated, it's just a few clicks to separate them as objects again…if they are overlapping - then it is more complicated. Honestly I have no idea how to prevent unauthorized use.
Comment: Thanks. Not sure if I missed this step when I first learned about arrays from a video tutorial. I just tried what you advised above and yes that works.Thanks also for instructions on how to provide a blend file. Would you advise to also reduce a collection to a single node to help prevent unauthorised use of models you may choose to release as freeware?


Can you make vegan garlic bread? If so, how does the use of margarine effect taste and texture?

Question: I enjoy a nice garlic baguette so much, but I have to drink a pre-emptive, schedule 5, painkiller not to die from being so lactose intolerant. I was wondering if a solution can be found that does not include narcotics, maybe substitute the butter for margarine? I know the French would call it barbaric, but can you do it?
Comment: If your question is 'what effect will replacing butter by margarine have on a garlic bread recipe', then that sounds like it will be on topic, but you need to edit your question title and body to reflect that. At present the question is just 'can you make vegan garlic bread', to which the answer is 'yes'.
Comment: You can actually substitute both butter and margarine with olive oil. Tastes great!
Comment: The short answer is 'yes', but that makes your question a recipe request. Recipe requests are a bad fit for this sort of site, so your question will probably get closed. But searching online for 'vegan garlic bread' will give you lots of options.
Comment: I'm actually more interested in how the sub affects the end product?
Comment: Does this answer your question? [Can I always use butter instead of margarine when baking?](https://cooking.stackexchange.com/questions/9165/can-i-always-use-butter-instead-of-margarine-when-baking)
Answer: Margarine will  not impact the texture, and probably will not alter the end result dramatically.  It, of course, is not butter, so as long as the flavor is fine with you.  But, you also don't need butter or margarine. You can use olive oil.  Sweat garlic in olive oil.  Proceed from that point.
Comment: I'd go with olive oil.  I can buy read-to-bake garlic baguettes made with butter, or slightly cheaper "economy" ones with margarine, and there's quite a difference in flavour & mouthfeel.  Olive oil is different to either but good in its own way (I've only made it with oil or butter in recent years)
Comment: As a former butter snob (*and I missed trans-fat margarines as a side effect, yay*) I can say that some of the current crop of non-butters (which notably don't tend to describe themselves as "margarine") are actually quite tolerable substitutes for the real thing. That would be unlikely to apply to "economy" commercial loaves, since on average the good non-butters cost MORE than actual butter.


ChatGPT and my PhD research

Question: I am currently a PhD student in the field of NLP and I can see a way how ChatGPT can solve my current research question. My research question is related to reasoning based on text. What can I possibly do to ensure that ChatGPT would not disrupt my research question? What are potential flaws of ChatGPT where we can focus on?
Comment: I think you have too broad of a question. Try to be more specific, like: what is your research question? Can you give an example of interaction with ChatGPT and point out the potential flaws/pitfalls?
Answer: Disclaimer: I don't know any detail about the ChatGPT model itself, this answer is based on my readings.
The question is quite vague, but ChatGPT has obvious flaws that are not difficult to find: even if it produces very high quality which looks exactly as if produced by a human, the main issue is always the same: it only looks like, it impressively mimics the data it was trained with, but of course the model doesn't have any understanding of what it produces. This implies that it cannot do any reasoning, and actually it doesn't have any way to even know if its information is correct or not, and it can happily invent things and make logical links which don't exist.
I found this article quite good at exhibiting the issue. There is also a whole discussion on StackOverflow and a well argued policy to ban ChatGPT answers, due to their complete lack of reliability.

ChatGPT and my PhD research


Magento Multi Theme Styling

Question: I've a multistore setup which is using a custom base theme for the structure but the colour scheme is to change per store. Is it possible to fall back to the base theme but only modify _var.scss per store?
Comment: Do you want to use RWD as your base theme
Comment: I am using a custom theme (called PDT) based of RWD. I then have 3 more store views which need to be based off the custom theme PDT but with a different colour scheme. All colour changes come out of _var.scss. I've got the templates working OK, it's the css which is the issue. Do I need to copy all the scss files for each store or can I reference the main PDT scss and only change the _var.scss file per store. Hope this makes sense :)
Comment: If you take a look at the link i posted in my answer. This runs through compiling sass from rwd parent theme, you can follow this same method but use rwd/yourcustomtheme as the parent theme instead of rwd/default. To compile sass you basically need to add import path into your sass config.rb which points to your custom themes sass directory.
Comment: Thanks for your help. I'll have a read of that article and let you know how I get on.
Comment: No probs it helped me get my head around building from rwd, good luck
Answer: Yes this is possible using Magento it's fallback system. In your new theme with the seperate color schemes you can define a fallback in a theme.xml.
<code><?xml version="1.0"?>
<theme>
    <parent>rwd/default</parent>
</theme>
</code>
There might be more useful options out there but this is the only obvious way I know.
For more information on theme fallback please refer to http://alanstorm.com/magento_infinite_fallback_theme_xml
Comment: Great in-depth article :) Learnt a lot from it. Thank you.
Answer: You can use RWD as your parent and base your multi store themes off of this using Magentos theme fallback
This is a really useful step by step guide on how you can achieve this
http://info2.magento.com/rs/magentoenterprise/images/Nirvana_Wiese_ClassyLlama_Fitness%20Center_Final.pdf
Comment: This was very helpful. The priority order of the import paths was the key. I imported RWD first then my custom PDT theme.

Magento Multi Theme Styling


Power of interactions in factorial ANOVA using G*Power

Question: I'm using GPower to perform a priori power analysis.
Let's say that I want to do a 2x2 factorial ANOVA. I'm interested in the power of the interaction. I set effect size f to .25, alpha value to .05, power to .80. The degree of freedom of my interaction is 1 and I have 2x2 = 4 groups. GPower calculates that I need 128 participants, 32 per cell.
Now, let's say I have a 2x2x2x2 factorial ANOVA. The degree of freedom of any one of the interactions, including the AxBxCxD, is still 1 and I now have 2x2x2x2 = 16 groups! Yet, GPower still calculates that I need 128 participants, namely only 8 participants per cell.
I'm a bit confused with this result. It seems to me that 8 participants per cell is very few to correctly power a AxBxCxD interaction…? If I set 30 groups, I still have 129 participants as a total sample size, that is less than 5 people per cell!
Does anyone could explain such a result? Am I wrong in using GPower or is there something I didn't get with power?
Answer: Reading this post, it seems that I am right in using GPower and that there is something I did not get with power... What matters would be N (total sample size) and not n (sample size per cell).


Please add "Not about cooking and eating" to close reasons

Question: I recently voted to close a question because it was about genetics and biology, not about cooking.  Looking through close reasons, I realized that "Question is not about cooking and eating food" was not an available close reason.  Seems like it should be?
Answer: I can't swear to it, but I'm pretty sure that 'This question is not about cooking' used to be among the close reasons. Now we've got 'a community-specific reason,' which certainly encompasses 'not about cooking.'
It causes me to suspect that the powers that be chose to ensure that those options were consistent across stacks.
I'll look into it
Comment: The submenu for "A community specific reason" doesn't include it.
Comment: Interestingly though, it is specifically used as an example for "other." maybe that's where I saw it before. At any rate, I agree that it should be one of our boilerplate reasons to close.
Answer: There hasn't ever been one. I see where you're coming from, and I agree that it would be nice having it. But seeing how little trouble it causes and how difficult it would be to have it otherwise, I see little chance of getting it.
The logic behind it
The first menu of closing reasons is network-wide. It's independent of scope, and contains the types of question which no site on the network takes, such as subjective questions.
One of the options is intended to be for out-of-scope questions. It's called "A community-specific reason" which I guess makes more sense from a network developer point of view than a closer's point of view, but is still recognizable.
Within that, each site is granted exactly three slots to use as a kind of "shortcut" to contain its most common off-topic close reasons. For anything else, it's "other". There's also the option to migrate to other sites, but I think that one is visible only to moderators.
The logic behind this is that people whose question gets closed are entitled to a short a situation-specific explanation. So there is not just a "out of scope" close reason, but a space to describe how exactly the question is out of scope. In fact, the three special reasons didn't exist at the beginning, and were added as a later feature, simply as a boilerplate that helps closers save time typing. Anything that doesn't fit the boilerplate needs a rationale, and that's hidden behind the "other" option.
How could this potentially get changed
There are two ways possible.
Replace a boilerplate reason
The first is to sacrifice one of our site-specific reasons and have this one instead. I would see this as counter-productive. While these reasons were intended as boilerplate, in reality, they're perceived as somehow "official". When the question is closed through "other" and the reason is given in a comment, new users tend to argue more that it's impossible that their perfectly food-related question is out of scope. Also, active users who recently got their closing privileges seem to be quicker to pick up on these reasons, probably because they read them more frequently than the help center.
This is why we prefer to keep our most counter-intuitive close reasons for the list. In fact, we'd like to have a fourth slot, because "no food pairing" and "no what can I cook with X" seem to be equally surprising rules, but we can't get it. I wouldn't want to lose the teaching moment here.
Also, I think Jeff's original logic holds here. The question isn't about cooking, but how isn't it about cooking? Being forced to write an explanation, even only a couple of words, makes it both easier for the OP (who sees that somebody at least took the time to understand their question and give them feedback, as opposed to rubber-stamping the reason) and for the wider community, who gets guidance as to where are the borders of our scope.
Programming changes to the closing interface
We could make a feature request for changing the interface. This would affect the closing box throughout the network, so the change has to be site-neutral, but it could have a positive effect on all sites.
An easy change to request would be to rename "other" into something more recognizable such as "out of scope", and maybe put it above the other reasons. This would help users to realize that it's the main option on the submenu, and not an afterthought.
Another would be to have it as a separate option on the submenu. I personally wouldn't like that one, because it would basically duplicate "other" (or, if you want to have it without the comment requirement, it would subvert the positive value of the comment) but maybe there are arguments for it.
My gut feeling is though, that such a request would have slim chances of getting implemented. This box hasn't changed in many years, even though there have been many requests, some of them garnering a lot of support. The product managers seem to have a feeling that it's one of the better working parts of the site, and not worth tinkering to remove minor flaws. Also, the current atmosphere on the network is certainly not conductive - there are fewer devs than before, working under more political pressure, and the community has many grievances about much more pressing features not being worked on.
So, you're free to make the request (I'd suggest looking through main Meta first, to see if there are already open requests for it). From there on, it's SE's decision.
Comment: So this is the first that any non-mod knew that we only get three options on the submenu.  You gotta know what non-mods don't know.
Comment: The main reason to have it is that the current use of "Other" introduces a disparity between asker effort and flagger effort.  That is, if someone asks a question that's wildly off-topic (like a question about sports teams or English usage) because they don't even bother to look at the URL, that's the thing that's the most effort to flag since I have to type in a reason.  But, if we only get 3 options, there's nothing we can do about it.


Kali Linux 2 on Raspberry Pi B - SSH autostart problems

Question: I recently got a Raspberry Pi model B and I decided to install Kali Linux 2 on it. The only problem I'm getting is SSH services (OpenSSH) won't start on boot no matter what I try, making it impossible to run it headless, and leaving me with a mass of wires. Any ideas why this is happening and how I could fix it?
Comment: is there anything related in boot logs?
Comment: When it boots it says something about "Stopping OpenBSD SSH services"
Answer: I was having the same problem and found a solution by reading through this thread: https://www.raspberrypi.org/forums/viewtopic.php?t=86950
First I did:
update-rc.d ssh defaults
update-rc.d ssh enable

and also I did:
systemctl enable ssh.

The last command resulted in this:
Synchronizing state of ssh.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable ssh
Created symlink /etc/systemd/system/sshd.service → /lib/systemd/system/ssh.service.


Determine the $\alpha$'s for which the integral converges $\int _0^4\:\frac{\sqrt{x}}{\left(4-x\right)^{\alpha }}dx $

Question: I have a problem that I don't know how to solve. I have to determin all $ \alpha $'s for which this integral converges:
$$ \int _0^4\:\:\frac{\sqrt{x}}{\left(4-x\right)^{\alpha }}dx $$ What I've tried:
$$ \int _0^4\:\:\frac{\sqrt{x}}{\left(4-x\right)^{\alpha }}dx = \lim _{x\to b}\left(\int _0^b\:\frac{\sqrt{x}}{\left(4-x\right)^{\alpha }}dx\right) $$ But from here I don't know how to solve this integral.
Comment: Consider $|\frac{\sqrt{x}}{(4-x)^\alpha)}| \leq \frac{2}{(4-x)^\alpha}$. If the right hand side is integrable then the left hand side is integrable. It is equivalent to consider the condition for the integrability of $\frac{1}{x^\alpha}$.
Answer: Look at the neighborhood of 0 and 4. In the neighborhood of 0 this integral equivalent to $\sqrt{x}/4^{\alpha}$. Now let us look at the neighborhood of 4. Integral equivalent to $2/(4-x)^{\alpha}$. This integral equals to $2/(-\alpha+1)(4-x)^{\alpha-1}$. So, $\alpha-1<0$


PHP mysql_query not returning false

Question: Just learning PHP and I'm having some trouble understanding mysql_query. My understanding is that mysql_query is supposed to return FALSE if the record is not found. However, it seems that it always returns true because "FOUND!" is always the result:
$q = "SELECT * FROM users WHERE username = 'doesnotexist'";

$r = mysql_query($q);

if (!$q) {
    echo "
NOT FOUND!
";
} else {
    echo "
FOUND!
";
}

mysql_close();

Thanks in advance for any light you can shed.
Answer: mysql_query returns false if there is an error, not if there are no results found. From the documentation:

For SELECT, SHOW, DESCRIBE, EXPLAIN
and other statements returning
resultset, mysql_query() returns a
resource on success, or FALSE on
error.
For other type of SQL statements,
INSERT, UPDATE, DELETE, DROP, etc,
mysql_query() returns TRUE on success
or FALSE on error.
mysql_query() will also fail and
return FALSE if the user does not have
permission to access the table(s)
referenced by the query.

If you want to check to see if there were results returned by your query, use mysql_num_rows(). See the documentation:

Use mysql_num_rows() to find out how
many rows were returned for a SELECT
statement or mysql_affected_rows() to
find out how many rows were affected
by a DELETE, INSERT, REPLACE, or
UPDATE statement.
Answer: You are checking the '$q' variable (your sql statement) instead of the '$r' variable (the mysql result)
Answer: if (empty($r)) {
        echo "
NOT FOUND!
";
} else {
        echo "
FOUND!
";
}

The following things are considered to be empty:
"" (an empty string)
0 (0 as an integer)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
var $var; (a variable declared, but without a value in a class)

Answer: Ok i have worked out the answer to this.
This is the version for updating a database that tells you if a record was valid.
$updatequery = "update `mydb` set `userid` = '$arr[0]', `name` = '$arr[1]' where `age` = '$arr[2]'";

$updatequeryresult= mysql_query($updatequery);

$howmanyupdatedrecords = mysql_affected_rows();

if ($howmanyupdatedrecords == 0) {
echo("The update didn't update any records as no one matched an age of " .$arr[2]");
}

This will iterate through the DB updating all people with the specified age, if the age does not exist in the DB a message will be displayed showing you the age that does not exist. Also something to note, even if the mysql query matches a record, it won't update the record if the data already matches what it is being updated to. This causes the script to return "no one matched an age" even though there are people who did match. Can only attribute that to a bug in mysql. I told MySQL to update the information I don't see why it should take it upon itself to not bother doing as i told it. ;)
Answer: Your 'if (!$q)' should be 'if (!$r)' I think.
Answer: if that dosen't work, try this:
<?php
$q = "SELECT * FROM users WHERE username = 'doesnotexist'";
$r = mysql_query($q);
if (!mysql_num_rows($r) >= 1) {
        echo "
NOT FOUND!
";
} else {
        echo "
FOUND!
";
}
mysql_close();
?>

PHP mysql_query not returning false


How can I stop my washing machine drain from overflowing?

Question: When my washing machine drains it sometimes comes up and out of the open pvc pipe in the service closet where the water heater would drain. I've found lots of posts where people speak of the washer standpipe overflowing, but can't find any info on what would cause my problem. When the washer drains I have to stand at the service closet (next to each other in the garage) and watch/listen. First I can hear gurgling, then hear the water coming up the pipe (similar to the sound of filling a glass of water), then I can see the water just before it emerges and floods my service closet and garage.  If I turn the washer off and on as it drains this doesn't happen...but not really feasible for the long run.  Any ideas?
Answer: It sounds like the pipe is partially blocked and water can only get through at a slower speed.  The drain at the hot water is the lowest point so that's why it is coming from there.  The blockage could be anything, from debris that came in through the pipe in the service closet or a sock that made it out of the washer.  Since it's after where the water is coming out of the service closet then you might be able to get a drain snake the problem but you might have to get an expert to get it cleaned out.
Answer: lqlarry is likely right, and using a snake to clean out the line is the first step. (+1 Larry)
It could also be a problem with the plumbing vent. If that is the issue, you would likely hear a gurgle after you shutoff the washing machine and the water gets down to the P-trap, not unlike the sound the toilet makes at the end of the flush.
The other issue I can think of is that the plumbing drain is improperly sized or sloped. If that's the case, this problem would have always happened, and wouldn't be a new issue.
Comment: Thanks for your responses. BMitch, it does gurgle, so that's good to know. I just bought the house so I don't know it's plumbing history. The home warranty people sent a plumber out who tried to snake it from the service closet, but he said it had a drum trap in the line instead of a P trap and he couldn't (?). I had another plumbing company come out last week and they thought the drain line is too small and too short. They're coming tomorrow to dig an outdoor cleanout as I have a problem with the back bathroom, but I'm unsure what to do about this issue. This second plumber wants me to file a
Answer: We hooked up water hose to a stopper from Ace. It kept water from coming back and force washed the clog out. I did use liquid Plumber followed w/hot water first. The clog looked like big pieces of dried washing powder.
Comment: Could you add a link to the stopper you used?
Answer: Think air behind water.  The drain must be properly vented for it to withstand the rush of water from a washing machine pump.
Answer: If the washer drains into a dry well, then the dry well is probably clogged with lint. You will have to dig it out or dig a new one. We had that problem at my son's house.
Answer: It's because the water flows out faster than the pipe can drain.  The easiest way to fix this is to seal up the washing machine waste hose against the open PVC pipe.  Some gaffer tape should do the trick.
Otherwise you could fit a holding tank above the drain which is allowed to fill and provides time enough for it to drain out without overflowing.
A harder option would be to increase the size of the waste pipe so that it can take a larger volume of water through it.
Comment: This is not a great idea because turning the drain pipe into a pressurized system rather than one with an air gap will create a siphon that will cause the washer to never stop draining once it starts and there is still water in the tub. This will obviously waste a huge amount of water, but it could also burn out the pump and cause a flood anyway as there's simply only so much water the pipe can accommodate. Start by snaking it and go from there.
Comment: Matt's right. I've lived in two separate houses with this same issues. Washers today drain at higher volumes than their predecessors in years past. Will try all ideas this time. But, last time, I recall using a fire hose to drain to the ditch... not a great idea, but what to do? what to do?
Comment: iLikeDirt - Pressure equalisation comes from the air inside the washing machine.  There is no siphon.  I've had to do the seal method and it worked but was done temporarily.  It didn't cause any problems at all and it indeed did drain.
Comment: That's true, as long as the machine isn't filling at the same time. Anytime it's both draining and filling, you'll get a siphon.
Comment: @iLikeDirt unfortunately due to bad old plumbing in my house i have to seal my house on to my drain. It usually works ok but sometimes it won't fill. Until i can fix the plumbing issue ( which I've traced to underneath the slab in my bathroom) what would you suggest i do to have it work consistently?
Comment: We got a 6' drain extension hose [like this one](https://smile.amazon.com/gp/product/B07SZFRZ92) and attached it using a hose clamp to the end of the existing drain hose. The water has to travel that much farther between the washing machine and the drain pipe, and the delay provides enough time to drain and prevents an overflow.
Answer: I only had that problem when I purchased a newer washer. I purchased a rubber piece from a hardware store, it came with two clamps that goes around each end. One end goes over the pipe and the other end goes over the rubber pipe to the washer. Tighten the clamps. No more problems with water backing out because of the tight seal. It didn't cost a lot and I didn't have to call a plumber which would have cost money and the problem not fixed.
Comment: What was this rubber piece called? Can you provide a link?
Answer: Get the washer drain piping snaked out. Have the plumber run down the vent stack for the washing machine. This should take care of your problem.
Answer: The end of drain hose is too deep down to the standpipe, it chokes. It should extend no more than 4" from the finishing end of the upside down U handle.
Answer: I had the same problem with a new washer overflowing an old drain pipe. Tried snaking it, Drano-ing it, and plundgering it but no luck - it still would not drain fast enough to keep up with the washer. This pipe was very old and runs under the house, so way too much work to try and increase its flow rate any more invasive other way.
So I ended up reducing the flow rate of the drain hose from the washer by inserting a section of vinyl hose into it. Costs about $5 at the hardware store. I iteratively added flow-reducing notches to the hose until the rate was right.
It has been several months and while the washer now takes a little longer to cycle, it has not overflowed again.
Answer: Firstly I'd make my best attempt at ensuring the drain line is clear. A basic handheld auger is relativity inexpensive at any box HW store and a worthwhile homeowner investment regardless. Other issues could be too many elbows or pipe is just undersized. Drain should use 1-1/2" pipe, utilizing a P-trap as well.
But if that all checks out or re-piping would be impractical a simple cheap modification would be to just install a 3/4" PCV coupling (Actual ID is 1") into the washer's drain piping. Ideally from under the washer, not in the flex drain hose itself. The intermediate connection between the washer and drain hose is usually 1-1/8". That connection will block the coupling from flowing past while providing a minimal restriction, slowing the flow only as much as is necessary.


How to pipe Bwa-mem output without saving SAM file

Question: I'm trying to find circular ARN using the program CIRI2. CIRI2 takes as input SAM file from BWA-mem, but I would like to go straight to CIRI2 output without saving SAM file.
Is there a way to achieve this?
Comment: This is an English language list. Do you by any chance mean RNA rather than ARN? And although I may be wrong, I think you are more likely to get an answer on SE Bioinformatics than here.
Answer: I never used CIRI2 but I think you can do the same way as I used to pipe with samtools:
bwa mem genome.fa reads.fastq | samtools sort -O BAM -o output.bam -
So it would be something like:
bwa mem genome.fa reads.fastq | CIRI2 <your options>
I think you will need to precise that CIRI2 input is STDIN.
I hope it will help,


Ductile metal makes sharper edge?

Question: I've read that, because it is so malleable, gold can be made into an extremely thin sheet, thinner than most other metals. Coming straight to the point, my question would be: While it would wear out practically instantly, would this allow gold to get a sharper edge than other metals, essentially becoming a super-single use scalpel? And how would it stack up against other super edges, like obsidian and diamond blades? Just curious.
Comment: Well, it would be 'super sharp' until any force were applied, at which point it would deform. So, not sharp in practice.
Comment: So, while sharp, it wouldn't be able to cut something or someone, as the simple act of trying to break their skin would already dull it without any effect?
Answer: Ductility is not related to the property of accept a sharp edge. As you said, it can be done also with brittle materials like obsidian or diamond.
Really it is more difficult to sharpen a gold sword than a quenched and tempered steel one. Fragments of material goes along with the cutting tool, instead of falling down as small chips. Sharpen is more a cutting process than a plastic deformation one.
But a gold sword with a sharp edge can hurt a lot anyway
Comment: About resharpening: scythes in partcular are also sharpened using hammering. This way of sharpening is called 'peening a scythe'. Resharpening by peening uses ductility of the material of course. I don't know how many cycles of resharpening by peening is possible. Presumably the steel will work harden.

Ductile metal makes sharper edge?


Finding a easy and cheap method for dyeing dNTP

Question: I want to measure OD to know the concentration of dNTP. Any idea for dyeing dNTP at cheapest price and easiest way ?
Answer: There may be such a dye, but I'm not aware of it.  The standard way to measure dNTPs, and nucleic acids in general is by absorbance at 260 nm. This article has a table of molar extinction coefficients for dNTPs (Table 10.2). They are
<code>        wavelength      molar extinction coefficient
dATP    259 nm          15,200
dCTP    280 nm          13,100
dGTP    253 nm          13,700
dTTP    267 nm           9,600
</code>
In practice for routine work with DNA you can use 260 nm and assume that an absorbance of 1 corresponds to [DNA] = 50 µg ml-1. Using an average of the values in the Table, and disregarding the fact that these are actually at different wavelengths, and using an approximate average dNTP MW of 500, I calculate an absorbance for a 50 µg ml-1 solution of all 4 dNTPs as 1.3, so that's a reasonable agreement given all of the assumptions I've made.
There are fluorescent dyes that can be used to measure DNA, but these rely upon the presence of stacked bases, so are not useful for free dNTPs.
So, bad news if you don't have a UV spectrophotometer. There are plans available for construction of simple spectrophotometers using Lego and a few optoelectronic components. These tend to use LEDs as a light source, but I don't know if UV LEDs are available.
Answer: It will be difficult to achieve the level of wavelength resolution required to differentiate dNTPs, considering that you are doing a DIY experiment. Only very precise spectrophotometers can achieve it and they are expensive.
Another technique you can try is thin layer chromatography(TLC). It is cheap and you can easily do a DIY. But you need standards in order to differentiate NTP, NDP and NMP; the latter two might arise because of degradation during the experiment. People generally use a cocktail of anti-oxidants and protectants to minimize the degradation of nucleotides.
A strategy to go about this is to remove the phosphate using phosphatase and then do a TLC with Nucleosides (which are quite stable).
You can check this review on nucleic acid TLC.


Resistance for different gear ratios

Question: Why are some gear ratios more difficult to pedal than others on a bicycle.
It feels as though I'm missing some very simple piece of reasoning!
Comment: It takes a certain amount of energy to move a bike 100 feet.  In a low gear (large rear sprocket) you turn the pedals around more times to get 100 feet, so there is less energy required per turn of the pedal.
Comment: Does it help to consider a car gearbox/motor?  The motor has a "preferred" or most-effective speed, and going faster or slower than that is sub-optimal.  The gearbox lets the motor stay near its best speeds.  Same goes for a bicycle.
Comment: Efficiency of some gear combinations is very slightly lower (like 1 or 2%). Especially for internal gear hubs.
Answer: To add to Nathan's correct answer, the concept at work here is mechanical advantage. Different gear ratios offer different mechanical advantages, and let you divide or multiply your torque to suit different conditions.
It's the same with a car: you pull away from a stop in 1st gear in a car, not 4th, because the engine doesn't have enough torque to manage it in 4th.
Comment: Oh, it's well possible to start driving a car in 4th gear. It'll just kill the clutch in the long run...
Answer: Divide the chainring tooth count by the cog tooth count. Multiply what you get by the circumference of the back tire. That's how far one rotation of the cranks is moving the bike. So why would that take the same amount of effort with two different gear ratios?
Answer: The amount of energy and power required to move your bicycle a certain distance at a certain speed should always be the same.
Power is torque times rotational speed. Shifting gears allows you to choose between pedalling harder (i.e. more torque) or quicker (i.e. more rotations per minute).
There is a very small amount of losses in the transmission (like 3%) which can vary depending on the gears you use (like ±1% or 2%). For example "cross chaining" (using the large chainring in the front and large sprocket in the back or vice versa) can increase losses. With internal gear hubs it's even more pronounced. But you'll probably be unable to feel (or even measure) it.

Resistance for different gear ratios


Modify the icon size on a 'list' web part in SP 2010

Question: I'm trying to change the width and height of the icon in the list web part.  However, I'm having difficulty finding the right element/class to do this with SP 2010. I have seen it done just by putting the style in a hidden Content Editor web part.  However, I'm having difficulty finding the right element/class combination to make it work. Does anyone have any suggestions on how to do this?
Answer: The icons in a list view in a document library are not loaded with CSS. The list view is generated with XSLT, which will create an IMG tag for each icon and another IMG tag for any icon overlays, like the check-out arrow or the record padlock.
On the rendered page, the list view is presented in an html table. The cell with the image has the class ms-vb-icon, but this class only contains css for padding. The cell then contains images for icon and overlay.
For a checked out Word document, for example the html looks similar to this (full file name replaced with dummy text)

The icon image size can be changed with CSS, but there are implications:

the image that is loaded from the SharePoint server has a fixed size and making it bigger will result in a blurry image
The overlay images that are generated dynamically will need to be adjusted to the different size of the underlying image

With that said, you can use the following CSS to manipulate the icon

Screenshots.
Before applying the CSS:

After applying the CSS:

I would use this very sparingly, load only on the page via Content Editor Web Part and not in a master page.
Comment: Sorry, I guess I was not specific enough.  I'm concerned about the image/icon that can be placed in front of the title for the list - actually an FAQ type list.  Here is a screen shot.
Comment: @Gman where is a screenshot? I still don't know what image you mean. Please edit your question and post a link to the screenshot.
Answer: For SharePoint 2010 you can can use this selector:
.ms-WPTitle img {}

For SharePoint 2013 you can use this one:
.ms-webpart-titleText img {}


Can't find IIS Rewrite Rule in Config XML

Question: I created a new URL rewrite rule through the IIS manager GUI. But when I browse to the site config XML file, I don't see any rewrite rules even though I have confirmed the rewrite is working. I had expected that the rewrite GUI would generate the corresponding XML in the config file. Is that not how it works?
Answer: When adding a rewrite rules to a site it should save it in the site's web.config.
One reason I can think of why you don't see it there, is that you added the rule on the server level rather than the site level.
When done on the server level it is saved in the ApplicationHost.config file.
<code> %systemroot%\System32\inetsrv\config\applicationHost.config
</code>
You can also define it on the folder level, it that case it is saved in a web.config file inside that folder.
Comment: Okay thanks, I found it. I had changed it on the site level, but was looking in the wrong place - I was looking in the Config folder within site. Not sure what the difference between the two is.
Comment: I had accidentally set my rewrite rules on the server level - so I did not see any on the site level.


How could Banner's gamma radiation exposure be both an accident and a self-experiment?

Question: In The Hulk (2003) movie it was shown that gamma exposure was an accident. However, in subsequent movies it was portrayed as self experimentation, so which theory is true?
Comment: @Gnemlock if it's self-experimentation, exposure is not an accident..?
Comment: Deliberate exposure does not mean you don't e.g. get a larger dose by accident than you intended.  Not sure if that's relevant to that particular movie, but as a general rule these things are not mutually exclusive.
Answer: The Hulk (2003) and The Incredible Hulk (2008) movies don't share a common universe (The Incredible Hulk is a reboot, not sequel). So, don't expect consistency.


Reporting correct CFA figure

Question: I am trying to understand what exactly to report in my final Confirmatory Factor Analysis figure. I plan on reporting standardised estimates with Squared multiple correlations. I am unsure what to report on the figure for the residual error variance, as I can only access these in unstandardised form. Is there a rule-of-thumb for reporting here that I am missing? Thanks.
Comment: A useful reference on what to report for publication purposes is Hancock & Mueller's The Reviewer's Guide to Quantitative Methods in the Social Sciences.
Answer: Typically, people report the full standardized solution, including factor variance(s), factor loadings and residuals. I'm surprised that your software doesn't provide the standardized residuals or have an option to do so. Finally, if you have multiple factors, then correlations between the factors should be provided as well.
Also, what do you mean squared multiple correlations? Usually the R-square is reported, which slightly different in emphasis (see What's the difference between multiple R and R squared?)

Reporting correct CFA figure