Linking a Navigation menu item to external URL

Question: 3 of 7 links on my navigation menu are external links to others websites (same company but other services/not the same domain). Those websites are not the core of the business.
Linking a navigation menu item to external URL is not good practice, is it? how can I solve this?
Comment: The nav menu at the top of a website is "premium" space, by putting links there you are telling the visitor that these links are more important then those below them. That is all there is to it. If you feel they are this important, then by all means put offsite links there. It doesn't matter where the links go, only that you think the visitor should be able to find them quickly and easily. That's what the top nav menu is for.
Comment: clear.
I would like explain a little more the main problem. We are a travel agency but this last year we opened up an online insurance -and car selling- ecommerce (yes... we did a study of the market).Therefore, we can say that we have a wide range of services.
Our website contains many links to other domains that don't share the same navigation menu nor the same style (colors, fonts, etc..).
Comment: Car companies do this all the time. They often have the top menu as jumping points to multiple car brands owned by the larger parent company. There is no rule anywhere that states a link has to be in the same domain.
Comment: Mathew, I agree with you but car companies do this because they only sell cars. By the way, do you think its good way to do it?.
Answer: Navigation is always an interesting topic, and should be treated with care in each case. If you have a target group at hand, or a selection of your target audience – use them. You could use Card Sorting to find out what your users think of all your pages and links belonging. As a designer you are sometimes amazed how user group pages together into logical entities.

In your case, they might group all the external links into one logical entity and label it "External Resources", then that would be your choice – adding an External Resources link to you navigation menu. The label could also be "Partners", "Vendors", "Manufacturers'" or the like.
But your users might also group in a different way, such as in sub groups. Let's say you have Products as a top navigation item, and you have external links to the manufacturer of this particular product, then user might feel that this link should be on these specific product pages, way down in the navigation hierarchy.
It all boils down to how your target users group all your pages, and what your external links represent.
Answer: Have you considered adding an external icon such as the usual globe and chain link icon?

download bmml source – Wireframes created with Balsamiq Mockups
Answer: If the websites aren't the core of the business I would never place them in the main navigation.
I might support the idea of external links in the navigation if the other sites have the same design and you could easily navigate between all websites.
I think that most users don't pay attention to the address bar unless they want to switch site.
Answer: When we send people to another site of ours, or another environment that is sufficiently different to cause confusion, we hit them with an alert in a lightbox.
This technique might work best with the visual cue method suggested by @TJH .
By using the icon on the link, and then carrying that icon through to the alert box, you help users who don't want to leave the current site to identify future external links.

download bmml source – Wireframes created with Balsamiq Mockups
Comment: I thought these annoying popups are for legal reasons, not that it would increase UX of majority people (even if some people, like me, get extremely annoyed)
Comment: Sure, people are generally bothered by those "Sign up for a free email newsletter" popups that appear a few seconds after landing on new site. Who wouldn't be? But when we test functional modal dialogs like the one described in my answer, that serve a meaningful purpose, and are a very common component of modern interaction design, we find that most reasonable users don't seem to mind at all. Most barely notice them. Some users, however, seem determined to be annoyed by features, even when they helpful, but we generally put this down to personality issues, rather than interaction design.
Comment: ah, I was talking about "The link you just clicked will take you to ..." in my first comment, that I felt surprised these can be considered helpful and not hated universally... I guess some of us have a "personality issue" that we already know where a link will go before we click on it, so having to read an unexpected message after the most trivial thing ever to do in a browser (click a link) might make us "determined to be annoyed"  ¯\_(ツ)_/¯ but as long as the middle click opens a new tab with the page without popup, we will be fine :)
Comment: I think you're missing the point here. This type of interaction isn't used for just any link in a menu, only those that take the user out of the current environment and into a different one. Ideally main navigation shouldn't contain external links, but when that is necessary, it makes sense to warn the user of this switch of environments.
Comment: The expectation is that while navigating a site, key elements like the navigation, typography, branding, etc. remain static. Dumping a user into a different environment (where these elements are different) with no warning leads to questions in the mind of the user like "Wait..what?" or "What just happened there?" or "Where am I now?". Good design is about avoiding this type internal monologue.
Comment: Most users don't have the psychic power of being able to "already know where a link will go before [they] click on it", (they have expectations that should be respected) nor do they go around middle-clicking links for the fun of it, and so for these users the act of switching environments without at least some warning will likely result in an erosion of trust, something that good design should seek to avoid at all costs.
Answer: Since the external links are not the core of the business, I'd recommend not placing them in the menu next to the core business links, but instead under one logical entity, like the previous answer suggested.
One reason to place it in the same menu I can think of, is from a charity organization: most of the content was just data that the user wasn't supposed to interact with, like articles etc. Then later was added one simple page where users could log in and view and update their information. That was in different domain but the link was placed in the menu. So essentially it was their core business, and there was only one item so it didn't became too confusing.


best way of using cuda

Question: There are ways of using cuda:

auto-paralleing tools such as PGI workstation;
wrapper such as Thrust(in STL style)
NVidia GPUSDK(runtime/driver API)

Which one is better for performance or learning curve or other factors?
Any suggestion?
Answer: Performance rankings will likely be 3, 2, 1.
Learning curve is (1+2), 3.
If you become a CUDA expert, then it will be next to impossible to beat the performance of your hand-rolled code using all the tricks in the book using the GPU SDK due to the control that it gives you.
That said, a wrapper like Thrust is written by NVIDIA engineers and shown on several problems to have 90-95+% efficiency compared with hand-rolled CUDA. The reductions, scans, and many cool iterators they have are useful for a wide class of problems too.
Auto-parallelizing tools tend to not do quite as good a job with the different memory types as karlphillip mentioned.
My preferred workflow is using Thrust to write as much as I can and then using the GPU SDK for the rest. This is largely a factor of not trading away too much performance to reduce development time and increase maintainability.
Answer: Go with the traditional CUDA SDK, for both performance and smaller learning curve.
CUDA exposes several types of memory (global, shared, texture) which have a dramatic impact on the performance of your application, there are great articles about it on the web.
This page is very interesting and mentions the great series of articles about CUDA on Dr. Dobb's.
Answer: I believe that the NVIDIA GPU SDK is the best, with a few caveats.  For example, try to avoid using the cutil.h functions, as these were written solely for use with the SDK, and I've personally, as well as many others, have run into some problems and bugs in them, that are hard to fix (There also is no documentation for this "library" and I've heard that NVIDIA does not support it at all)
Instead, as you mentioned, use the one of the two provided APIs.  In particular I recommend the Runtime API, as it is a higher level API, and so you don't have to worry quite as much about all of the low level implementation details as you do in the Device API.
Both APIs are fully documented in the CUDA Programming Guide and CUDA Reference Guide, both of which are updated and provided with each CUDA release.
Answer: It depends on what you want to do on the GPU. If your algorithm would highly benefit from the things thrust can offer, like reduction, prefix, sum, then thrust is definitely worth a try and I bet you can't write the code faster yourself in pure CUDA C.
However if you're porting already parallel algorithms from the CPU to the GPU, it might be easier to write them in plain CUDA C. I had already successful projects with a good speedup going this route, and the CPU/GPU code that does the actual calculations is almost identical.
You can combine the two paradigms to some extend, but as far as I know you're launching new kernels for each thrust call, if you want to have all in one big fat kernel (taking too frequent kernel starts out of the equation), you have to use plain CUDA C with the SDK.
I find the pure CUDA C actually easier to learn, as it gives you quite a good understanding on what is going on on the GPU. Thrust adds a lot of magic between your lines of code.
I never used auto-paralleing tools such as PGI workstation, but I wouldn't advise to add even more "magic" into the equation.

best way of using cuda


How can I build a vanilla chunk loader without access to spawn chunks?

Question: I have an iron farm on an SMP server. I want it to be loaded constantly. I know about the spawn chunk related methods (placing it there and hopper clock to there and back) but I can't build in the spawn chunks because they are rival territory. I heard about using a tamed dog to keep the chunk loaded; does that work? If not, are there any other chunk loaders that don't require spawn chunks?
Comment: Does the Nether portal work?
Comment: Can't; my server for some reason lumps all the portals together into one in the nether
Answer: I'm sorry to say, that currently using the spawn chunks is the only way to do it. I tested the Tamed Dog chunk loader myself and it did not work. For now, we will just have to wait until there is a feature or bug you can exploit. You could try AFK iron farming, although that is not recommended on all servers, so if you would like to know to do that I would recommend writing another question or editing this one. You could build up your power and take over the enemy territory though.
Answer: I think i've might've found a design that dousn't requite spawnchunks.
It is quite advanced / expensive, but i think it could be worth it to load iron farm.

Not 100% sure if it still works thought.
Comment: You should include important parts of the video in your answer in case the video is no longer available someday.
Answer: Have you tried using pistons to load the cunks just string them together so that the pusher goes into the next chunk.


What are the differences between natural major, harmonic major and melodic major scales?

Question: The natural major scale on C has the notes: C, D, E, F, G, A, B. What is the difference between natural major, harmonic major, and melodic major scales. What notes of the natural major are changed  in harmonic/melodic major?
Comment: @Tim: It's wrong, but enharmonically correct. It should be C D E F G Ab B.
Comment: @MichaelCurtis: The question is about major scales, not minor scales.
Comment: The sixth and seventh scale degrees are lowered or raised to produce the various minor scales. There are several existing posts that go into the details.
Comment: Just googled 'harmonic major' and got the notes (in key C)- C D E F G G# B. Surely that ain't right?
Comment: My answer to this question goes into some detail that you might find helpful: https://music.stackexchange.com/questions/91091/is-the-i-iv-v-i-progression-of-a-minor-melodic-or-harmonic/91094#91094
Comment: Well, the harmonic major scale is the major scale with a flatted sixth? But what about the **melodic major**?
Comment: @MattL. yup, I read too fast. The silly thing is the answer is still the same: the sixth and seventh degree are altered.
Answer: The harmonic major scale has a lowered 6th scale degree:
1 2 3 4 5 b6 7
The only difference with the harmonic minor scale is the major third, so harmonic major can be obtained from the harmonic minor scale by raising the third.
Raising the third of the melodic minor scale results in a standard major scale, so that's not the way melodic major can be derived.
The term "melodic major" is actually hardly used, but it usually refers to the 5th mode of the melodic minor scale with scale degrees
1 2 3 4 5 b6 b7
This scale is more commonly (and more understandably) referred to as mixolydian b6.
Answer: From what I understand, Harmonic Major flattens the 6th degree of natural major: [C D E F G A♭ B]. Melodic Major flattens the 6th and 7th degree of natural major: [C D E F G A♭ B♭].
As for why: The upper tetrachord of harmonic major is identical to that of harmonic minor. For melodic major, the modified 6th and 7th give the scale its "melodic" moniker. AFAIK, these scales are played identically both ascending and descending.
Another possible reasoning for the name of melodic major is from its identity as a mode of melodic minor (the 5th mode, to be specific).
Answer: On ascending, what I'd think of as "melodic major" can only be the same as regular Major (Ionian). Harmonic Major is just Harmonic Minor with a raised 3rd, and Aeolian n6 n7 with a raised 3rd is just Ionian again.
But it's still possible to see melodic major as a distinct scale because melodic minor can be considered different when ascending and descending. On the way down, you can just use natural minor again. Raising the 3rd of natural minor gives you Aeolian Dominant, which fits what I'd think of as "melodic" major.
You could have C-D-E-F-G-A-B-C (ascending) and C-Bb-Ab-G-F-E-D-C (descending).
To me melodic major has kind of a contemplative, melancholy, bittersweet feel, mostly because it has I iv.
Comment: I don't think you're using the term "melodic major" the same way that the OP was; your answer takes the melodic minor scale and raises the 3rd, but the scale commonly referred to under that name has flattened the 6th and 7th of major instead.


How does a catalyst accelerate both forward/reverse reactions simultaneously?

Question: A catalyst is known to speed up both forward/backward reactions of a reversible reaction. But how does this work, because the mechanism for the forward and backward reactions could be different right? I mean the adsorbed species for the forward and backward reactions when conducted independently will be different right? Is that because all the steps are exactly reversible?
Answer: The idea is that the activation energies is lowered for both the forward and backward reactions.

Though the activation energy for the backward reaction is higher than the activation energy for the forward reaction, it is nevertheless lowered.
To answer your second question, reactions aren't always reversible, but a lot of the time they are, and are subject to the principle of microscopic reversibility. That means when reactions are performed as a series of steps, at equilibrium, each individual reaction occurs in such a way that the forward and reverse rates of reaction are equal, and these equilibriums can be affected to drive the reaction one way or the other.
Comment: how does this assumption of microscopic reversibility hold good in reality?can I assume  a catalyst that accelerates the forward reaction can also be used to catalyze the baxckward reaction always(given thermodynamic limitations of course)?sometimes catalyst chemically decompose in presence of some reatants and it is this decomposed state that actively catalyzes the reaction. But when you start with the products and do the reverse reaction I am not sure if the same exact decomposed states woud be formed
Comment: It's very important in synthetic organic chemistry. It simplifies what you need to know (if you know the forward reaction you know the backward reaction as well), it can help you to predict side products, and it can make undoing a reaction easier by understanding what changes need to be made to affect the equilibrium one way or the other.
Comment: so any catalyst that accelerates forward reaction(in heterogeneous gas-solid reactions) will be equally effective if I need to accelerate the reverse reaction as well? Is this true under all circumstances, just for confirmation?
Comment: Yes. This doesn't change yield at all, but the rates of reaction are effected equally.
Answer: The equilibrium constant for the reaction is equal to the ratio of the forward rate constant to the reverse rate constant.  In order for the equilibrium constant to be independent of the catalytic effect, the forward and reverse rates must speed up equally.
Answer: One of the implications of the second law of thermodynamics is that, if a catalyst increases the rate of the forward reaction by a factor of, say, 745492, it obligatorily increases the rate of the reverse reaction by the same factor, 745492, despite the fact that the two reactions - forward and reverse - may be entirely different (e.g. the diffusion factor is crucial for one but not important for the other) and accordingly require entirely different catalytic strategies. The absurd implication is usually referred to as "Catalysts do not shift chemical equilibrium".
A paradigmatic example of the inability of catalysts to accelerate both - forward and reverse - reactions to the same extent are diffusion-controlled reactions:
Wikipedia: "Diffusion-controlled (or diffusion-limited) reactions are reactions that occur so quickly that the reaction rate is the rate of transport of the reactants through the reaction medium (usually a solution). As quickly as the reactants encounter each other, they react. The process of chemical reaction can be considered as involving the diffusion of reactants until they encounter each other in the right stoichiometry and form an activated complex which can form the product species. The observed rate of chemical reactions is, generally speaking, the rate of the slowest or "rate determining" step. In diffusion controlled reactions the formation of products from the activated complex is much faster than the diffusion of reactants and thus the rate is governed by collision frequency."
Can a catalyst accelerate a diffusion-controlled reaction? Obviously not - catalysts do not accelerate diffusion. On the other hand, nothing prevents the catalyst from accelerating the reverse reaction, which means shifting the equilibrium and is tantamount to violating the second law of thermodynamics:
Consider the association-dissociation reaction
A + B <-> C
which is in equilibrium. Let us assume that the forward reaction
A + B -> C
is diffusion-controlled. The reverse
C -> A + B
is not diffusion-controlled, obviously.
We add a catalyst, e.g. a macroscopic catalytic surface, and it starts splitting C so efficiently that the rate of the reverse (dissociation) reaction increases by a factor of, say, 745492. If the second law of thermodynamics is obeyed, the catalyst must increase the rate of the forward (association) reaction by exactly the same factor, 745492, which is impossible - the catalyst cannot accelerate the forward reaction at all!
Scientists have always known that catalysts do shift chemical equilibirum:
https://www.facebook.com/ParadigmEnergy/posts/249600938581128
 "For 50 years scientists have seen in experiments that some monomers and dimers split apart and rejoin at different rates on different surfaces. The eureka moment came when we recognized that by placing two different surfaces close together in a way that effectively eliminates the gas cloud, the energy balance would be different on each of the two surfaces. One surface would have more molecules breaking apart, cooling it, while the other surface would have more molecules joining back together, warming it."
The second-law-violating effect is presented by Wikipedia as a fact:
Wikipedia: "Epicatalysis is a newly identified class of gas-surface heterogeneous catalysis in which specific gas-surface reactions shift gas phase species concentrations away from those normally associated with gas-phase equilibrium. [...] A traditional catalyst adheres to three general principles, namely: 1) it speeds up a chemical reaction; 2) it participates in, but is not consumed by, the reaction; and 3) it does not change the chemical equilibrium of the reaction. Epicatalysts overcome the third principle..."
Wikipedia: "Consider a dimeric gas (A2) that is susceptible to endothermic dissociation or exothermic recombination (A2 <-> 2A). The gas is housed between two surfaces (S1 and S2), whose chemical reactivities are distinct with respect to the gas. Specifically, let S1 preferentially dissociate dimer A2 and desorb monomer A, while S2 preferentially recombines monomers A and desorbs dimer A2. [...]
http://upload.wikimedia.org/wikipedia/commons/c/ce/NatureSLTD-Fig1c.jpg
In 2014 Duncan's temperature paradox was experimentally realized, utilizing hydrogen dissociation on high-temperature transition metals (tungsten and rhenium). Ironically, these experiments support the predictions of the paradox and provide laboratory evidence for second law breakdown."
Answer: The point missing so far in the answers is that a catalyst causes the reaction to occur by a different mechanism than it would normally take. (This is why its actually very hard to find good catalysts)
The catalyst lowers the activation energy but its not the same barrier as without the catalyst. So in that sense it does not 'lower the barrier' as commonly stated.
As the reactant and products are still at the same relative energy (no matter if catalysed or not) but the reaction occurs by a lower activation barrier then both forward and reverse rate constants are speeded up.


Star Trek Voyager - Species 8472 vs. the Borg

Question: How come the Borg could not adapt to Species 8472? Voyager was able to create nano probes that could destroy Species 8472 and yet the Borg couldn't figure that out? Why?
Comment: Of course they could figure that out, but they didn't want to destroy them. They wanted to assimilate them.
Answer: From Memory Alpha:

[T]he Borg learned about different species solely by means of assimilation; they were unable to understand or adapt to Species 8472's technology. This organically based technology was more than a match for Borg defenses. Species 8472's vessels were nearly impervious to all types of conventional weaponry, while their weapons were able to penetrate Borg shields with ease.

The issue is that the Borg didn't know a solution to how to assimilate 8472, and they grow their knowledge through assimilation, not experimentation and creativity like humans.
Comment: Not sure I follow. If the Borg can only learn about species by assimilating them, this means any species could have had the same tactical upper hand as Species 8472 did (at least initially). IIRC, in Q Who the Borg didn't assimilate any humans but the Enterprise wasn't able to easily destroy the Borg cube. With this theory all it would take to destroy the Borg was to find a species that the Borg hadn't assimilated and wouldn't be able to defend themselves against.
Comment: @Celeritas It's not about the species but about their technology, which previously assimilated species' might also have developed in a similar fashion. And in Q Who, a whole piece of Enterprise, including its occupants, was cut out and probably assimilated later on. 8472 were just _too_ different for the Borg to efficiently adapt. Yet. They probably would have figured something out _some_ day, assuming 8472 hadn't wiped them out by then...
Answer: The borg adapt in several ways:

grab someone who knows how to defeat technology X
examine technology X to find a known pattern

In the case of adapting to phasers, it's just a matter of figuring out the frequency shift patterns and adjusting shields to match it.
in the case of cloaks, etc, it's a matter of observing it happen, and then being able to process fast enough to spot the small but important telltales.

try semi-random adaptation attempts from the standard library until something works.

In the case of 8472, they hadn't found the needed combination yet, and appear to have been trying approach 3.

Humans make intuitive "fill-in-the-gaps" while borg don't.
Humans tend to qualitatively judge while borg seem to boolean judge things; this allows humans to better detect similarity of a failure that took longer to fail and of success.
Humans thus could see what partially worked as a partial success, and go from there, while the borg simply chalk that attempt as a failure.

until the borg have failed in all major trees, they are unlikely to start looking at various branches of failed tree stems; given their history, they have a LOT of stems to try before they get to additional branches of stems where the stem didn't succeed.
due to 8472's successes versus the borg, reports were limited  as to what had been tried, leading to duplication of failed attempts.
Answer: When the Borg attempted to assimilate Species 8472, they found that the species was immune to assimilation -- their immune system was so efficient that any foreign body their cells encountered was immediately destroyed, including Borg nanoprobes.
Moreover, since the Borg learned about different species solely by means of assimilation; they were unable to understand or adapt to Species 8472's technology.
from memory alpha
Answer: They actually mentioned this in Scorpion 1 I believe. Janeway mentioned in the briefing that the Borg learn via assimilation and what they can't assimilate, they can't understand. The Voyager crew however study things to learn. They look at the data they've collected and figure out the best possible actions by trial and error and testing.
Comment: It's also important to note that from what we have seen through TNG and VOY, that whatever they assimilate is ONLY what they understand.  In Best of Both Worlds, a rotating phaser modulation was used to get past the personal Borg shields.  The same was also used on the ship phasers.  It's likely to assume that since that trick worked, they were only experienced with weapons at specific modulations, meaning that no previous race that had been assimilated had tried it, otherwise the Borg may have been able to steamroll the away team or the ship.


Which are the advantages of low pressure levels during flight? (i.e during cruise flight in a commercial aircraft)

Question: I understand that due to health and security reasons, there must be a minimum in the pressure inside the cabin (75 kPa). But in class I have been told that maintaining low pressure levels has advantages, which ones?
Comment: Related: "*Cabin pressure is limited to 8000ft maximum, due to structural fuselage meeting (otherwise it would "explode" as a balloon)*" from [How does the cabin pressure controller work in a large commercial airliner?](https://aviation.stackexchange.com/q/26283/3201). This is to keep the pressure difference between outside (lower as altitude increases) and inside as low as acceptable, to prevent using a stronger but heavier fuselage.
Answer: You want the lowest pressure that can be tolerated by most of the population for the purpose of maintaining adequate blood oxygen levels, which is generally considered to be 8000 ft above sea level. At 8000 ft, someone with degraded lung function, like a smoker, is effectively at 10000 ft plus and is already at the threshold of having marginal blood oxygen for peak brain function.
At 40000 ft this requires a pressure differential of a little over 8 psi between the interior and exterior and you build the pressure hull to that and no more (it's a certification requirement).  As per min's comment this is partly to keep from having to make the pressure hull any stronger than it needs to be (every pound over the minimum is non-revenue ballast) and also to minimize engine bleed demand, which can be thought of as lost energy being used to keep the balloon of the pressure hull inflated instead of making thrust.  So, bottom line is it would be better for the airplane, both structurally and from an energy use standpoint, to operate with lower pressure differential and higher cabin altitude, but now the crew would have to start using supplemental oxygen and more people in the back would be getting sick.
The 787, because of its carbon fuselage, is able to go with a higher differential structurally, and its electric-pump pressurization system is a bit more efficient than taking bleed air directly, so Boeing had the option to certify to a higher differential pressure, 9 psi, which gives a 6000 ft cabin at service ceiling.  They could have used 8 psi and just shaved off more weight and used slightly lighter air pumps, but instead they increased the differential.  This was done mostly as a cabin comfort sales feature and was thought of as a bigger sales benefit than going with the weight saving route.
Answer: When transporting animals, particularly larger (zoo, show) animals, it is often requested by the handler/vet to have higher pressure altitudes.  This helps calm the animal, and makes them less active.
In contrast, for long medvac flights, it was company practice to keep the cabin pressure altitude as low as possible, unless the medical personnel requested otherwise. There is of course supplemental O2 for patients at all times.
Comment: A friend, reading this, reminded me of a flight we had, with his daughter on board, who is very allergic to bee stings.  We were in his P210, and almost at altitude.  I turned on the O2, we put on masks, and depressurized the cabin.  Within minutes, the bee was stationary, and was dispatched.  Then the cabin was re-pressurized, with no bee threat.


Singapore Math textbooks for secondary/"high school"?

Question: Could anyone familiar with Singapore please tell me what is the name of a common textbook used for Math in Singapore's secondary schools? I am looking for topics covered for ages 14-18. I am very interested in what I have heard about Singapore's math education, so it's mostly to see their approach since I also do not like the vast majority of American math textbooks.
Comment: Note "Singapore Math" is a trademark for a math curriculum originating in the US, used in many schools.  Do you mean this?  Or do you mean a math curriculum actually used in Singapore?
Comment: Yes, very true. I am referring specifically though to the math curriculum actually used in Singapore.
Comment: I think Singapore Math has a common core version they are marketing in the US, so if you want the real Singapore Math be careful to avoid that. Sadly I don't know the name of the one to avoid. But, my wife has researched this in depth as she was purchasing curriculum for our children. We use Singapore Math, very happy with it. Both conceptual and computationally solid. Early algebra integration and steady development of simple to more complex algebra skills with every grade. It is very well thought out. It's also light years ahead of standard curricula in the US as far as I know.
Comment: Yes. I have taken a look at some of those samples, and it reinforces my view about how behind the curriculum is in this country.
Comment: @RyanG I think pretty much 6 to 16 year olds. Something like that.
Answer: I'm only moderately familiar with Singapore, but here is what I know.
There was an older textbook series for ages 12 to 16 called "New Elementary Mathematics: Syllabus D" Books 1 to 4. I doubt all schools used it, but I think it was from the same publishing company that put out the elementary-level books that were eventually sold in the U.S. I'm not sure what they use now.
The series was formerly sold in the United States. Here is a review by, I assume, a homeschooling U.S. parent: https://cathyduffyreviews.com/homeschool-reviews-core-curricula/math/math-grades-7-8/new-elementary-mathematics
If you do a search for "Ordinary Level Mathematics" (ages 12-16), "Additional Mathematics" (ages 14-16) and "Advanced Level Mathematics" (ages 16-18), you'll turn up some materials used now.
See here for the official curricula at O-Level: https://en.wikipedia.org/wiki/Singapore-Cambridge_GCE_Ordinary_Level
For A-Level, you ought to be able to find syllabi by searching for H1 Mathematics, H2 Mathematics, H2 Further Mathematics and H3 Mathematics. According to this thread, textbooks aren't widely used at this level, but there are textbooks for similar exams offered by "Cambridge International" up to the "Further Maths" level: https://www.reddit.com/r/SGExams/comments/jzz91o/a_levels_h2_maths_and_further_maths_textbook/
The entire Singapore curriculum at the secondary level is modelled on older curricula in use in England (probably about pre-1985). So if you want more textbooks like that, you can look at the books in use in England in that period. They were very different from the ones used now because at that time the top 25% had their own curricula and were sometimes educated in separate schools. Beware of pre-1970 books, though, as they use Imperial units and non-decimal (!) currency.
If you want to see what was typical in the early 1980s for ages 11 to 15 or 16 in England (in the top 25%), there are some books on the Internet Archive called "New General Mathematics for West Africa" by Channon and McLeish Smith. These are basically the same as the British textbooks but with "London" replaced with "Lagos" and pounds with local currencies, etc. (I'm not saying these are the best textbooks, but at least you can look at them.) For "Additional Mathematics" for advanced students at ages 15-16, see "Pure Mathematics: A First Course" by Backhouse, also on the Internet Archive. This was also a first-year book at Advanced Level (age 16-17) for those who hadn't taken Additional Mathematics. I believe all of this is quite similar in approach to the Singapore curriculum.
The main difference between the Singapore syllabus and most English syllabi about pre-1980 appears to be that some pure geometry was taken out and some vectors and transformations added in.

Edit: Here are some links to official syllabi and additional information provided to me in the comments.
O-Level:
2023 syllabus for O-Level Mathematics (Pure Mathematics, Probability & Statistics)
Specimen Paper 1 for O-Level Mathematics
Specimen Paper 2 for O-Level Mathematics
2023 syllabus for O-Level Additional Mathematics (Pure Mathematics)
Specimen Paper 1 for O-Level Additional Mathematics
Specimen Paper 2 for O-Level Additional Mathematics
A-Level:
2023 syllabus for H2 Mathematics (Pure Mathematics : Probability & Statistics = 7:3)
with Additional Mathematics as prerequisite
2023 syllabus for H2 Further Mathematics (Pure Mathematics : Probability & Statistics = 3:1)
with H2 Mathematics as corequisite
2023 syllabus for H3 Mathematics (Pure Mathematics)
with H2 Mathematics as corequisite
List of formulae for A-Level Mathematics
2023 syllabus for H1 Mathematics (Pure Mathematics : Probability & Statistics = 4:6)
restricted to non-H2 candidates; a proper subset of Additional Mathematics and H2 Mathematics
The O-level (Elementary) Mathematics course takes place over four years (13-16yo), and the Additional Mathematics alongside it over the final 2 years (15-16yo); they are designed to occur in parallel, so the texts don't overlap, although some pre-requisite stuff from EM does get reviewed at the beginning of the relevant AM chapters, and complementary topics across the two subjects occur alongside each other.
About half of all 16-year-olds take Additional Mathematics, a minority which will go on (17-18yo) to take H1 Mathematics instead of H2 Mathematics, which will have been taken by half of all the college students (most of the STEM ones and some of the non-STEM ones). H2 Further Mathematics is a very unpopular course; almost nobody takes H3 Mathematics.
About 30% of H2 Mathematics overlaps (at different depths) with Additional Mathematics, and about 60% of the latter overlaps with the former.
Comment: Thank you! This is exactly what I needed! Very helpful. I will look into all of that you have mentioned.
Comment: I found this paper from the mid-2000s about math education in Singapore: https://tatagyes.files.wordpress.com/2007/10/kaur_paper.pdf So I'm correcting some mistakes in my answer.
Comment: If you're interested in seeing older books from England (about 1930-1950), you'll find some at http://www.knowledge-dojo.com/ One of the characteristics of the system in Britain is that mechanics has been part of many math syllabi at about age 15-18. (I say "many" because different examining boards have always had slightly different requirements for their various exams.)
Comment: @Wasp I've found this self-published textbook for H2 Mathematics. In the preface, the author is very critical of the way math is generally taught in Singapore at the 16 to 18 stage. https://sites.google.com/view/h2mathematicstextbook/home There also seem to be various commercial textbooks for H2 Mathematics, but I haven't found anything for H2 Further Mathematics.
Comment: @Wasp Some recent textbooks from Marshall Cavendish: "Mathematics Matters Express" Books 1 to 4 (textbooks and workbooks), "Additional Maths 360", "H2 Mathematics: A Comprehensive Guide for A-Level" Volumes 1, 2. The "Express" in the first title refers to the Express stream in secondary school, for the top 60% of students leaving primary school. I suspect that the market for Further Mathematics may be too small for any textbooks to be profitable.
Comment: Thanks for all your help, Anonymous.
Comment: @Ryan: Thanks. That syllabus and sample exam is very helpful. From the looks of it, seems very similar to the UK "papers".
Comment: An edited version of a comment I made earlier: Those Additional Mathematics exams look pretty tough for a 16-year-old. Especially the fact that you have to answer all the questions in just 2 1/4 hours. For comparison, here are some Additional Mathematics papers from England in 1979 (note the freedom of choice in questions, as well as the inclusion of mechanics): https://telescoper.wordpress.com/2019/07/01/additional-mathematics-o-level-1979/
Answer: There are no common textbook(s) widely used across schools.
Instead, each individual school/teacher will usually have their own notes (that they guard jealously but are usually leaked out).
Check out this "Holy Grail" collection of resources (mostly exam papers but also has some notes).
Comment: Thank you! This is great! It is EXACTLY what I needed.
Comment: Wow. Anyone who has only read American calculus textbooks will find the approach and problems found in these notes quite fresh. Very nice.
Answer: Anonymous' answer is excellent and comprehensive. To add on to that, as a Singaporean, I can share my experience with the education system here.
For ages 13-16 (secondary school) different teachers tend to have their own teaching materials, whereas for ages 17-18 (junior college) notes tend to be issued on a per-school basis, referred to as "lecture notes". To my knowledge, there is no standard textbook widely used in the country for any secondary school / junior college level math education.
However, it should also be noted that Singapore's education system has different "tracks" for students of varying academic levels / interests, most notably for ages 13-16 there are the Normal (Technical), Normal (Academic), and Express tracks, whereas for ages 17-18 there are Junior Colleges and then there are Polytechnics. Details may vary widely based on the different academic tracks, or based on the school, or even based on the individual teacher. It may be the case that a particular teacher chooses to work with a certain textbook for example, though most in my experience do not.
To answer your underlying question of what is taught in Singapore's math education system, I suggest you to Google "Singapore O Level math syllabus" and "Singapore A Level math syllabus". (Edit: I realised these were already mentioned in Anonymous' answer.) O Levels are a national exam generally taken at the end of the year for 16 year olds, and the A levels are generally taken for 18 year olds. The syllabus documents are made publicly available by the national exam board, the SEAB, online. All teachers in Singapore teach based on these exam syllabi and many have an exam-centric approach, so this is a very good guide to what is actually taught in classrooms.
If you have further questions, feel free to ask in the comments.
Comment: Thank you! This has been very informative. I just checked out the syllabus, and it looks quite good. I am pleased that I have been able to access the "holy grail".


PEK-ORD-YYZ - Re-check Luggage in Chicago?

Question: Baggage checked from Beijing to Toronto (via Chicago) on United.   Will I need to collect luggage in Chicago and re-check for final leg from Chicago to Toronto?
Answer: Yes you will have to collect and recheck baggage. You will go through US Customs and Border Protection too.
Step 1 : Arrive at O'Hare International Terminal 5
Step 2 : Proceed to Customs and Border Protection (CBP Processing Area - Immigration Inspection
Step 3 : Claim Baggage
Step 4 : Proceed to CBP Processing Area - Customs and Agriculture Inspections
Step 5 : Connecting Flights/Transfers

http://www.flychicago.com/ohare/myflight/international/pages/default.aspx

Here is a really neat visual guide
Comment: @MartinArgerami IAH, United, and CBP have a special system for international-to-international connections where you don't need to collect and recheck your baggage. That's not the norm in the US though, just something they've setup at IAH. The rechecking process is normally quite fast though; it's just a drop-off where they scan the tags and put them on a belt, not a whole check-in counter.
Comment: Are you positive about this? In the last few years, when I flew EZE-IAH-YYC and EZE-IAH-YYZ with United, my baggage was checked through to Canada. I had to clear US immigration, but I didn't have to get my baggage nor re-check it.
Answer: Yes. When you land in Chicago you will go through US passport control. After that point, you will need to collect your bags prior to rechecking them on the other side.


Laws regarding putting someone to death for violating the sabbath

Question: Two witnesses go to the beit din and claim that so and so violated the sabbath on a biblical level. The witnesses claim they warned him in accordance with the rules and they did their part as witnesses. When so and so is brought to beis din, he claims he did a melacha (such as digging a hole), but he claims it was for the dirt. Which would only be a rabbinical prohibition because it's a מלאכה שאין צריכה לגופה. If a person were to use this as their defense to deflect the death penalty would it theoretically work?
Comment: Somewhat related (to the topic, but not the underlying principle): http://judaism.stackexchange.com/q/61002
Comment: If you like an answer, consider marking it correct.
Comment: *warned him in accordance with the rules* - the rules say that he must be explained that if he does it intentionally he's liable to a capital punishment and **he has to answer loudly I know all that and that's why I do it!**. If he does not say exactly that or stays silent - he cannot be proven to be guilty.
Answer: The Maharsha (Bava Basra 119a) discusses the case of the m'kosheish eitzim (the man who gathered wood on the Sabbath, see B'midbar 15:32-36). The Maharsha mentions that, according to Targum Yonasan (B'midbar 15:32), the man was not gathering wood for actual use. Instead, he was gathering wood in order to precipitate a divine revelation of the appropriate form of death penalty for a Sabbath violator.1
The Maharsha asks how the m'kosheish could have been liable to the death penalty according to Rabbi Shim'on, who exempts a m'lacha she'eina tz'richa l'gufa2 from liability. After all, the m'kosheish gathered the wood with an intent unrelated to the wood itself. The Maharsha answers that even though the m'kosheish was theoretically exempt according to R' Shim'on, he was still liable to be killed in a court since the witnesses were not made aware of his intentions at the time that they warned him:

ומיהו הוא ודאי דהיה חייב מיתה בדיני אדם שלא ידעו העדים שהתרו בו שהוא עשה על דעת זו ואינן אלא דברים שבלב ודנין היו אותו למיתה ע"פ העדות

Translation:

However, he was certainly liable for a court imposed death penalty, since the witnesses that warned him did not know that the violator performed the act with this intention, and his intention constitutes only unspoken thoughts [of which the witnesses were unaware, and which have no legal significance to the court], and they sentenced him to death based on the testimony.

Apparently, had he informed the witnesses initially that he was performing a m'lacha she'eina tz'richa l'gufa, he could not have been held liable in court (according to Rabbi Shim'on).3 Perhaps the Maharsha would even concede that a person would be exempt from punishment if the circumstances at the time of the m'lacha act suggest it was likely a m'lacha she'eina tz'richa l'gufa.

1 Alternatively, according to Tosafos (Bava Basra 119b, s.v. אפילו קטנה) he was demonstrating that the rest of the generation that was already condemned to a heavenly death penalty (for accepting the report of the spies, see B'midbar 14:20-35) was still obligated to follow the commandments.
2 Forbidden labor performed for some purpose other than the type of purpose for which that labor was performed in the construction of the mishkan (or also, according to some opinions, performed for the service of the mishkan). For example, digging a hole to get dirt rather than to create a furrow would be eina t'zricha l'gufa.
3 Though in the particular instance of the m'kosheish eitzim, as understood by those sources that say he was trying to get himself executed, such an exculpatory admission would have defeated his purpose.
Comment: Forget about a מלאכה שאין צריכה לגופה! A person can say that he was doing בונה and he didn't know בונה was אסור he can claim he only thought there were 38 melachos and בונה wasn't one of them!
Comment: @DavidFeigen Well, if Tz'lofchad was a *talmid chacham*, then, according to R' Yose b. Y'huda, he would not require *hasra'a* and there would be a presumption that he knew *hilchos Shabbos* properly.
Comment: What or who is tz'lofchad?
Comment: @DavidFeigen He is the person who R' Akiva identified as the *m'kosheish eitzim* (the person who was executed for gathering wood on Shabbos, see *B'midbar* [15:32-36](http://mechon-mamre.org/p/pt/pt0415.htm#32)). He is the subject of the Maharsha's discussion, considering that the *m'kosheish eitzim* could have argued (and perhaps correctly so) that he was doing a *m'lacha she'eina tz'richa l'gufa*.
Comment: Can you show me specifically where  it talks about  tz'lofchad?
Comment: @DavidFeigen The source is [*Shabbos* 96b](http://hebrewbooks.org/shas.aspx?mesechta=2&daf=96b&format=text): ת"ר מקושש זה צלפחד... דברי ר' עקיבא... In short, R' Akiva identifies the *m'kosheish* as T'zlofchad, and R' Y'huda ben B'seira criticizes this identification because it denigrates an innocent man if it is incorrect, and, even if it is correct, it reveals information that the Torah intentionally obscured (since R' Akiva's exposition is not based on an exegetical tradition for a *g'zeira shava*). (Presumably, R' Akiva could respond to this, but his response is not mentioned explicitly).
Comment: @DavidFeigen (For background on who Tz'lofchad was, see [this Wikipedia entry](https://en.wikipedia.org/wiki/Daughters_of_Zelophehad)).
Answer: Sanhedrin 40b:

תנו רבנן מכירים אתם אותו נכרי הרג ישראל הרג התריתם בו קיבל עליו התראה התיר עצמו למיתה המית בתוך כדי דיבור
(paraphrased) They ask the witnesses, "did he accept the warning and accept that he would be killed?"

Rashi on התיר עצמו למיתה:

התיר עצמו למיתה - שכשהתריתם בו אל תעבור שאתה מתחייב מיתה פלונית הוא אומר על מנת כן אני עושה דאם לא הפקיר עצמו אינו נהרג כדלקמן
When you warned him, you said "do not violate this because you will get a death penalty for it" and he said "I am doing it on that condition" - if he does not accept that he will be killed for doing it, he is not killed

Part of his warning was his acknowledgement that he will be killed for what he is about to do.  Additionally, the warning must contain the specific prohibition that he is violating, complete with the name of the Av or Toldah of the Melacha (Tosefos based on Shabbos 138a). So he admitted exactly what act he was performing as part of accepting his warning, and he cannot deny later that he was doing exactly what he admitted to two witnesses that he was doing.
Comment: There's still a problem with that. Let me give you an example, if two witnesses view a man digging a hole, and they warn him that digging a hole is forbidden because of choresh (plowing), so  he says "i don't care I'm doing it anyway." Later in beis din he claims that the digging was for בונה (construction purposes). Both are מלאכה דאורייתא. However if he admits to the choresh he will get the מיתה. His escape route will be to claim in beis din that they warned him for choresh, and that he was really doing boneh
Comment: @DavidFeigen the warning includes which melacha he is doing. So they say "You are doing the melacha of choresh, and you will be killed for it." He says "I know, I am doing it even though I will be killed." So he can't later claim he was doing boneh, he admitted to doing choresh.
Comment: He could admit whatever he wants to the witnesses, but the loophole is מחשבה in beis din
Comment: @DavidFeigen Because he says yes to what they said!!!1!eleven
Comment: If this case is regarding a person who does the melacha solely to be executed then it should be an ein gufa because the "gufa" is his execution he derived no real benefit from the melacha......


Detect token transaction to a contract

Question: Is there a way to detect when my contract receive tokens? I don't own the token contract, I only want to know the address and amount of token sent to my contract.
Answer: If you know which token your contract expects to receive, you can listen for a Transfer event issued by the token contract. (Not your contract!)
The standard ERC20 Transfer event looks like this:
event Transfer(address indexed _from, address indexed _to, uint _value);

...so listen to the token contract for an event where _to is the address of your contract.
If you don't have a specific contract in mind and you want to know when ownership of any token is transferred to your contract, you would theoretically need to listen for any Transfer event from any contract on the blockchain with your contract's address in the _to field. Unfortunately the available tools will mostly assume that you want to listen to the events of a particular contract, so this may be difficult to do in practice.
The above approach only works for a process outside the blockchain, that is able to listen for logs. Most commonly this would be JavaScript code using the watch and listen functions in web3.js. If you want your Solidity contract code to respond to an ERC 20 transfer then you're probably out of luck; A standard ERC20 token won't call your contract's code for you in the way that a normal ETH transfer would. In theory you might be able to incentivize someone to listen for the events and send a transaction to relay that information to your contract, possibly with a merkle proof to show that they really saw what they are suggesting in the logs, but this wouldn't be trivial to do. Alternatively you may be able to set up a workflow such that the user calls your contract to make the transaction happen, and your contract in turn calls the token contract; That way your contract knows about the transfer because it directed the transfer itself. The approve and transferFrom methods in the ERC20 standard are designed for cases like this.
Comment: Thank you for your answer. That was what I thought. Unfortunately, I want the contract to be completely decentralized and the token contract didn't implement approve.
Comment: One more option might be to wrap the original token contract with a more advanced proxy contract that implements approve, or other code you need. However, you'd have to get your users using your proxy contract.

Detect token transaction to a contract


How to keep it interesting before the inciting incident?

Question: My novel technically has two inciting incidents: One in the first chapter, and another five chapters later. The later incident really kicks off the story. What can I do to make sure that everything that happens before this, the first five chapters, are interesting enough to keep the reader going until he/she gets properly established in the story?
Comment: Except that if you cut everything before the inciting incident, there will be no reason to care about the inciting incident. The inciting incident has to happen to someone in particular that we care about. Yes, there are often things we should cut. But the real issue is to create the things we should create. An editor can cut what you should have cut. Only you can create what you should have created.
Comment: If there's stuff in the novel that isn't interesting, cut it.  If nothing before the incident furthers the plot, cut it all.
Comment: @Lew Not really. He is asking about technique for a particular issue in a particular part of the novel. The fact that the answer (per me anyway) is "write interesting exposition" does not make the *question* a how to write question, not a too broad question. Sometimes narrow questions have broad answers, because the narrow case is simply an instance of a broad case. But others could still have the same narrow question and find the same broad answer useful.
Comment: But you have no problems keeping the story interesting after the second inciting incident? Why? Is it because you now know what to write, and you did not before? @CHEESE is right—if it feels like your narration is stalling, throw those parts away.
Comment: Remember the most important rule (#17 in Strunk&White's *Elements of Style*): **Omit needless words!**   This works for sentences, paragraphs, pages, and chapters as well.
Comment: @MarkBaker Then he is asking how to write an interesting exposition, and it is the very same flesh on the bones of the story, sadly--a *what to write* question.
Comment: @MarkBaker I couldn't agree more. "Omit needless words" isn't bad advice exactly, but it's not always clear what's meant by "needless". We didn't *need* to write *anything*. If the words help the reader to care about what comes next, they're of *some* value, right? Like you say, the trick isn't (always) to get rid of them, but (often) to find a way to make them interesting.
Comment: While I agree to an extent with other commenters saying you should cut out what you don't need for the plot I would be wary of cutting out too much, especially if these bits before the event you're talking about are all about establishing characters, the world, etc, otherwise you might fall victim to the 8 deadly words.  If you think you're lacking pace, trim down what's not essential to either plot, character or world, and spice up what remains.  You can have other events happen in the buildup that maybe hint at the big one, for example.
Comment: Be interested in those first 5 chapters yourself for a start. You may think that second inciting incident is the cool part, but you also have spent a lot of time thinking about these characters and are very familiar with them. Your readers haven't. They may need a moment to get acclimatized, and those moments may not be as dreadful as you imagine them to be. As long as you have sufficient tension, you don't always need a major plot element to keep readers gripped. The first 1/3 to 1/2 of the gunslinger for an example that was fairly popular.
Answer: Inciting incident is a term for one of the bones of a story, the thing that give it shape. But while a story needs shape, shape alone is not enough. The basic story shapes are well enough known and not particularly complicated. Anyone who does a little elementary research should be able to write a story that follows correct story shape.
But while shape is important, it is not where the money is. You have to put flesh on the bones. What the reader encounters when they read is not the bones but the flesh. Without good bones the flesh will seem deformed. But beyond freedom from basic deformities, it is the flesh that attracts us, creates our interest, and holds it.
What does the flesh consist of? Its fundamental attractions are sensual. A good story engages us at the sensual level. I don't mean sexual here, though it can certainly be that, I mean it creates an experience for the senses. It creates a world that has depth and grit and light and texture peopled by people who feel real and animated and particular.
None of this is in the structure. It is in the telling. It begins with observation and sympathy and love and proceeds through care and craft and a sensitive gift for language and the images and experiences it evokes. The way you hold the reader's interest up to the inciting incident is simple, and yet the hardest part of writing: you make it real.
And until you make it real, the inciting incident is for nothing. It incites nothing unless we are first made to care, unless we are made to feel that this is a real thing happening to real people in a real world.
Anyone can assemble the bones. The diagrams are in all the books. Assembling the bones of a story is no more complex than assembling an Ikea bookcase. If the bones of a story end up misshapen it is either because the writer paid no attention to them at all, or because when the writer attempted to apply flesh to the bones they could not get the muscle and sinew right and it pulled the bones out of shape.
There are very obvious and teachable techniques for the bones. The technique for the flesh is mastery of observation and language. That's the hard part. It is why so many aspiring writers will never achieve their aims. There is no formula for it. If it is not simply inspired, it is learned by osmosis from living, reading, and writing.
Answer: Just because your inciting incident hasn't occured, it doesn't mean what happens has to be boring. To take Mark Baker's meat-on-the-bones metaphor a little further (some might say "too far"), consider that there are plenty of novels that pride themselves on being invertabrates (Julio Cortazar's "Hopscotch" comes to mind), wherein the skeleton is absent or obscured. The reader reads such things for the meat alone.
Now, the very fact that you're asking this question suggests to me that this isn't the sort of thing you're trying to write, but they help to remind us that there are plenty of things besides plot that make a story interesting.

The language itself can be beautiful.
The content can be though provoking, thematically compelling, or intriguingly disorientating.
The scenes themselves can be captivating (in the way a good short story is) while having little to do with the main plot.
The characters can be sufficiently interesting that we want to find out more about them (regardless of their goals, or what they're actually doing in the context of the story).
You can hint (or, if your narrative style permits, outright tell the reader) that things are going to go wrong soon, and the reader (if you do it right) will be watching closely for signs that this is about to happen. If you keep tricking them into thinking it's just around the corner, you may be able to keep them reading for longer than they otherwise would.
You can exploit the reader's understanding of narrative conventions, such that they know where things are heading even though there are no in-universe signs. (Things being "too perfect" is a good example of this, though it's a difficult trick to pull off.)
You can set up another conflict for your characters, and allow the reader to temporarily invest in this while you lay the groundwork for the real conflict (i.e. a MacGuffin).

I think it's good to bear in mind that the only real duty you have to your reader is to not waste their time. If your main plot doesn't start until chapter six or seven, that's perfectly fine, just as long as the reader has a good time getting there, and - having arrived - doesn't feel like that time was wasted. My advice is to worry a little less about your main plot (it seems like you already have that part covered), and just make them good. How you do that, exactly, is up to you.
Answer: I'm going to use the example of one of my all-time favourite anime, Steins;Gate, which also has two inciting incidents.
The first is Okabe accidentally inventing the time machine and shifting himself into a parallel World Line. This occurs midway through Episode 1, though he and the audience don't realize that's what's happened until about Episode 3.
The second inciting incident occurs at the end of Episode 12, and I won't spoil what it is because it's such a WHAM moment and sets up the entire second half of the storyline. It's worth noting, however, that it's actually a direct consequence of the first incident.
The episodes in between those events serve several purposes:

To introduce the main characters in detail, and help us get to know them and sympathize with them, in a fun and entertaining manner
To provide important exposition (in this case, about the mechanics of time travel) so that once the main plot kicks in, the boring bits are out of the way and we can just get on with the main story
To hint at future plot developments

The section between your two inciting incidents needs to try and hit those points as well.
Answer: The first moments of a story should introduce the setting and the characters. Reader / viewer should understand who are the characters, what is their world, how this world works, and so on. I believe this is a very important part of a story, sometimes more than the incident itself: we would not understand the gravity of the incident, if it wouldn't happen to a clearly built character. Of course you can start in medias res, but if it's a long story I would spend some time in building the world.
Answer:
My novel technically has two inciting incidents: One in the first chapter, and another five chapters later. The later incident really kicks off the story.

So... that makes me think that the first incident kicks off a subplot that allows the world and the characters to be set. Then there's a second incident that kicks off the main plot.
I see nothing wrong with it. In fact, I've just been tutoring a kid (highschool level Portuguese literature) where he's studying a novel that has that exact structure. Subplot with a tragic family story that sets up the stage for the main plot, where the main character, while showing himself superior to his tragic family member, ends up in a greater tragedy.
All you have to make sure is that the initial subplot is important to the setting and has an interesting arc of itself. Imagine you're writing a short-story that is composed solely of that initial subplot: would it make an interesting read? If not, either cut it out or make it interesting per se. How? Ignore the fact that this is supposed to be the setting for something greater and treat it as a story per se: make sure that there's a goal driving the main character(s) and that the characters are interesting.


Using particle data to effect an unrelated objects material

Question:
Basically the sphere has an emission shader that I want to only emit when a particle passes through it.
It is supposed to be a muzzle flash from a firearm and right now I have to manually animate it to line up with each particle. So the question is there a way to have each particle effect the emission shader. I was thinking that I could use particle age but I have no way to link it between the two different objects materials. Is there some way to have the particles weight paint the sphere kind of like you can do with two objects? Or should I make the muzzle flash a particle system too? that copies the emission pattern of the bullets.
Answer: Using dynamic paint
Result:

How to:

UV unwrap your "receiver" object (I'm using a cylinder)

On that object, enable (from the Physics panel): Dynamic Paint > Canvas > Add Canvas. Make its type "Image Sequence", and its initial color completely black. Enable "Dissolve" and use a very short time for dissolve, like 5.

Select the Emitter object, enable: Dynamic Paint > Canvas > Add Brush. Make the brush fully white. Change the "Source" to "Particle system" and select the correct particle system. Increase the brush radius.

Go back to the target object, select the correct "UVMap" under "Dynamic Paint Output", and bake the Image Sequence.

Create a material for the target that has an emission shader modulated by the Dynamic Paint paintmap (for the Image Texture, remember to open all the image files together with Ctrl+Shift+Select, and "Detect Sequences" activated):
Comment: Very helpful thank you. However, I have multiple particle systems because this is supposed to be a gun firing and because of how the particles work if I want it to have a 3 round burst at frame 10 then have another 3 round burst at frame 20 I have to have two separate systems that are copies but with different emission start times. Can I select two systems as the same brush?
Comment: nevermind I found a workaround thank you for this helpful answer.
Comment: glad it helped! anyway you can add several brushes to the same emitter
Comment: Yea my workaround solved that issue entirely I have it contained to one particle system.


Where can I find an English dub of Naruto Shippuden episodes 78-140?

Question: So I just got into Naruto a few months ago and have been binge-watching my way through the entire series. I watch some subbed anime but after watching so many episodes dubbed I just can't get used to subbed episodes. I've gotten to episode 77 and suddenly the dubbing is gone. The dub doesn't start again until episode 140 on Hulu, and I can't seem to find it anywhere online. Did they just never dub those episodes or is there something I'm missing?
Answer: On the Anime and Manga Meta we have a list of Legal Streaming Sites. i don't stream myself so i wouldn't know if the episodes are on there. do be aware that some sites do employ Geoblocking which, depending on where you live, you may be redirected to a local site or prevented from using it all together (as with some Youtube Chanels)
If the Episodes you are looking to Stream are not there the other alternative and legal path is to buy the DVDs. Dubbed wise Collections 6-11 have Episodes 66-140. this RightStuf Search Result has these Collections available to buy, they ship internationally but the DVDs are Region 1, which is fine if you are in the US or have the equipment/programs to use Region 1 DVDs (ie. a Region Free Player).
if you are in Australia then Madman list some of these collections but not all of them (no idea why they just stop after Collection 8)


Including letters and other documents in a memoir

Question: Writing my memoirs. I would like an opinion on how best to include 4 pages of letters/fax/emails. How about a 20-page composition? as addendum/exhibit? Too long to include in manuscript? Thanks for any help you can offer.
Comment: Welcome to Writing.SE Jaensch.  Thanks for starting off with a great question. I edited it a bit for you, including changing the title to make it more specific (and more likely to get eyeballs).
Answer: Use an appendix
The appendix is the perfect spot for longer documents you wish to include within a work (not just for a memoir).  You can have as many as you want.
Name each appendix.  Appendix A, Appendix B, is perfectly fine.  Or use a name that doesn't have the word "appendix" in it if you prefer.  The 20 page composition gets its own appendix.  The 4 pages of letters/fax/emails can share another appendix.
Have a table of contents that lists each appendix and gives the page number where it begins.
Within the text, discuss the material like you would any other material you assume a reader has access to elsewhere.  Clearly give the location within your book so readers who wish to can go read it first, or refer to it later.
For shorter pieces, you can include them in the text at the spot where you discuss them.  For anything taking up all or most of a page, or more than one page, set it off with a special page border or change the background color or even the font.  It should be obvious to the reader that it is separate from your narrative.
Very short pieces can be set off on the page with a box, with your narrative taking up the rest of the space on the page.
You can decide if you want the shorter pieces to be collected into one or more appendices, in the main text, or both. Though try to limit duplicate pages.
You may also decide to just take small quotes from the documents for the main text and put the full documents into the appendices.


How can I get my Particle-Board Cabinet re-staining project looking more professional please?

Question: So, I am working on changing the stain on my particle-board cabinet(disassembled). I sanded, and then pre-stained the various pieces. I have also applied the first coat of stain(ebony) to the wood pieces, but I keep getting finger-prints and various marks on it as I move the pieces around. How do I get rid of those from the dried pieces? What is the best way to store the pieces away to dry?  My other question is now that the pieces are dry, I guess I need to apply the sealer, in my case, minwax quick-dry polyurethane clear gloss,is there anything else I can do to make the finished product appear as if it was professionally done? I am using MinWax Wood Finish which claims to be both a stain, and sealer, do I need sealer still?
 And please how do I get rid of the smell when I am done? Is there a trick to this I can apply here?
Comment: Given that it's particle board and is never going to look like real wood, and given that you're going with ebony as the color, I'd have suggested just giving it a coat of black paint.
Comment: Why black paint?
Comment: What do you mean 'particle board cabinet'? Are you staining actual particle board?
Comment: Lacquer over ebony dye over particle board is mostly going to look like glossy black paint anyway.
Comment: What is Lacquer? The ebony does appear to be black and not ebony at all. And I have yet to apply the polyurathane on it.
Comment: (Lacquer: Should have said "varnish", of any kind. And ebony, or "ebonized" wood, is often nearly black, so I'm not sure what you expected it to be.)
Answer: Do what a professional would do - don't touch it when wet.
Sand the affected areas with fine grit and re-stain, leave until it dries completely, then move, flip over and do the opposite side, etc. Apply the poly in the same manner. You cannot handle pieces until they dry fully. You also cannot handle them with hands that are wet with finish.
Comment: Then you need to go over it with 80 until you see no scratches from the 40, 120 or 150 until you see no scratches from the 80, 220 until you see no scratches from the 120 and then you might be able to apply stain and hope not to see sanding marks....
Comment: What if I need to add a second coat of stain? Is that after the first completely dries? I did sand the pieces before applying pre-conditioner but after applying my stain, I see sander markings all over. Do I apply a second coat and a third until those marks disappear?
Comment: What grit sandpaper are you using?
Comment: Let it dry COMPLETELY between coats. If you're seeing sanding marks, you either didn't sand enough (or evenly enough), didn't sand to a fine enough grit, or didn't clean the board after sanding to remove sawdust before starting to apply stain/paint/lacquer.
Comment: I used 40 and I did not completely take off the original color as I was afraid I would look the grain patterns which I wanted to keep. Or I am wrong in this?
Comment: I hope that's a typo and you meant 400 - 40 would be through the veneer in no time and leave huge scratches.
Comment: I did use 40. I wanted to remove some of the first stain
Comment: WOW. Is that how it works? OMG
Comment: Well, according to the directions, 15 minutes after painting, I need to clean excess off it with a clean rag. This is where the issue stems from.
Answer: With real wood, proper technique with stain is to apply, let it soak in, wipe off excess which wasn't absorbed (by the less porous parts of the grain pattern), let it dry completely, evaluate the result, and repeat the whole sequence if/where you aren't getting the contrast you want. Then apply varnish over the top to seal it and protect it, again letting it dry between coats.
But particle board has no grain, so there isn't any differential absorption and you might as well just leave it there.
Sanding should be essentially complete before you begin applying surface treatments. Poly may want a very light sanding between layers to slightly roughen the surface and encourage the layers to bond with each other; read the manufacturer's instructions, and always wipe down with a tack cloth or microfiber cloth to remove sanding dust before applying the next coat. The final layer can be "rubbed out" after it has cured completely for a smoother surface and higher gloss, but that calls for very fine abrasives -- in fact, simply rubbing it with a paper bag is sometimes sufficient.
Books can be, and have been, written on the subject of finishing ... but I'm not sure particle board calls for much more than "don't mess it up."
Comment: Actually -- I'm making a bad assumption here. Is this particle board, or veneer over particle board? If the latter, then yes, you can refinish it like refinishing wood... but you need to be extremely careful not to sand through the veneer (or be prepared to apply a new layer of veneer, or to give up and paint it, if you do overshoot.)
Comment: Ikea type particle-board
Comment: Can you help respond to the other questions I have too?
Answer: If its what I'm thinking it is( a thermal-foiled particle board) you are doomed to failure. Most production grade furniture is made of this material and it will never take stain or finish the way you want it to. Basically they take particle board and wrap it in a micron thick layer of (usually) pvc foil with a wood grain printed on it. The foil is specifically designed to be nonabsorbent so it repels stains, and it has a particularly high molecular count so nothing sticks to it. That's pretty much the opposite of what you want when your trying to refinish something.
You can scuff sand it (but you'll almost certainly sand off some of the print) and apply a product like PolyShade (stain and finish in one) but it will be an uphill battle. You'll probably have adhesion problems, any vertical surface will take the color unevenly because the pigment settles to the bottom, any overlaps will show as the color doubles up, and on and on.  Sorry to be a kill joy.
Answer: First off, I would not recommend staining particle board. If I'm picturing it correctly, you're working with an Ikea product that's essentially compressed sawdust held together by glue and two thin sheets of veneer, right? If the veneer is real wood, then you have a shot at staining with a good result. Otherwise, stick with paint.
For staining, you'll need to progressively sand with finer and finer grits. Since you started with 40 (I would usually start with 80 or possibly 120 if the surface was already smooth), next use 80, 120, and then 220. Your goal with each pass is to smooth out the surface so no scratches exist that are larger than the current grit that you are using is capable of producing. A random orbital sander should be ok for the whole process, but if you're using a simple rotary sander you'll need to sand by hand in the direction of the grain for your 120 and 220 passes. Otherwise you'll get swirl marks. With veneer you also have to be careful not to sand through. This may be very difficult in your case since you started with 40 grit.
Next wipe down the surface with a very slightly damp rag to remove all the sawdust. Let it dry out COMPLETELY afterwards. Then you're ready to apply wood conditioner. Follow the directions on the packaging.
Next, apply your stain. Wear gloves for this part. I use a foam brush and apply it in the direction of the grain. Keep a wet edge and work from one side of the piece to the other. After waiting the amount of time specified in the directions, carefully wipe off the excess stain, once again in the direction of the grain. The longer you leave it on, the darker it will be.
After letting the stain dry completely (and possibly applying a second coat),  you're ready for poly. Make sure the surface is dust free, and STIR the poly (never shake, which introduces air bubbles). Apply using a foam brush, or one you don't mind cleaning with the appropriate solvent. If using a foam brush, don't squeeze it against the workpiece, which can also cause bubbles. Sand with 220 grit or higher between coats, and make sure to wipe away all dust this creates before applying the next one.
Lastly, to avoid any fingerprints or marks during the whole process, do not touch the piece until it is dry. Don't try to relocate it while wet. Just accept the fact that you may have to take longer if you don't have a large enough work space to do it all at once.
Answer: The cabinets probably do have a "finish" on them as opposed to being bare particle board.  If so, the comment above about not being able to stain is correct, and you will need to paint.  If they don't have a finish on them, particle board will suck up A LOT, A LOT of stain and can get expensive, so even then painting instead of staining may be a better option.  I found some great information on ehow.com when I searched for "how to paint particle board to look like wood."  For an even better effect, in addition to their instructions, use a wood graining tool, which is a rubber thingy with "teeth combs" and "wood patterns" (get a good quality one from a paint store instead of wal-mart).  I removed the doors from the cabinets and laid the doors on cinder blocks so I could paint the edges as well as the surfaces.  I used my dining room to leave them on the blocks until dry and ate in the living room. If you don't have that space, a technique I used in the past when painting interior doors is hammer nails into the top and bottom edges of the doors so they could be leaned against a wall to paint and let dry, thus allowing you to paint the edges of the doors.  if you do this, you will end up with visible nail holes in the top and bottom edges (which of course on an interior door is not an issue because the top and bottom edges of a door are not visible).  If you do this, you will have to be creative in filling the nail holes with wood putty and then use an artists paintbrush to paint the holes.  Good luck!


Is medium-resolution a good middle ground for web images?

Question: I'm used to thinking of hi-res 300 ppi and above, and lo-res, 72 or 96. But today I got an image that was 240 ppi, and da boss wanted as high res as possible. It was a huge file, but when I resized down to 700px wide in PS, optimized jpeg with no compression, without changing the res the result was a 129KB file that looks decent on most browsers (at least my box...who knows about old monitors, etc.) Did I miss a conference when I was on a break? Are others doing medium-res?
Comment: You can use high resolution and compress images using something like http://www.jpegmini.com/ which works beautifully.
Answer: From The 72 PPI Web Resolution Myth:

The size at which an image appears on your screen depends only on two things – the pixel dimensions of the image and the display resolution of your screen. As long as you've set your screen to its native display resolution...then an image will be displayed pixel-for-pixel. In other words, each pixel in the image will take up exactly one pixel on your screen. For example, a 640×480 pixel image would fill a 640×480 pixel area of your screen. An 800 pixel-wide banner on a website would appear 800 pixels wide on the screen. No more, no less. And no matter what you set the image's resolution to in Photoshop, whether it's 72 ppi, 300 ppi or 3000 ppi, it will have no effect at all on how large or small the image appears on the screen.
That's because image resolution affects only one thing – the size of the image when it's printed. By setting the resolution in Photoshop, we tell the printer, not the screen, how many of the pixels in the image to squeeze into an inch of paper. The more pixels you're squeezing into every inch of paper, the smaller the image will appear when printed.

So if you set your images to 200 ppi, they will just print much smaller than they appear on the screen.


Edits in Oracle Spatial Layers

Question: I have an Oracle spatial layer that is built on top of a multi table view. When I make a new feature in QGIS, I get an error when I attempt to the save the edit. When I look in the database and refresh the QGIS view, the new features are present, so the error is being thrown even though the operation is successful. The errors says could not retrieve feature id -2 and has a sql statement where it looks like QGIS is quering by rowid. I was wondering if anyone elese has seen something similar to this or if it is possible to have qgis not use Oracle rowid as a check.
Comment: Welcome to gis.stackexchange! Please edit the title of your question to include enough information for future visitors to be able to find this thread when looking for the same problem.
Answer: Can you show the SQL definition of the view?
Generally only simple views are updatable in Oracle (and other RDBMSs): views that select columns and rows in a single table. Anything else: aggregates, joins, subqueries ... are not.
You can make them updatable by adding an INSTEAD OF trigger to the view where you write the logic to apply to properly update the underlying tables.
The other issue is with ROWIDs. Those are physical pointers to table rows. A join view does not have any. So yes, you need to tell QGIS to find another way to identify rows in the view. However that is only possible if the view is "key-preserved" i.e if each row has a unique key that exists in both tables, i.e the join is a simple inner join.
Comment: Thanks for the information. I have instead of triggers on top of the views to make them editable. I have a primary key on the view but it seems like QGIS is not recognizing it eventhough I specify a primary key.
Comment: Hmmm I have had that sort of issues with Mapinfo in the past. QGIS is fairly simple-minded. It thinks you are giving it a table and looks for a primary key or unique index that it can use internally. And that must be a single-column numeric. But obviously finds none. Mapinfo had a workaround: just name one column MI_PRINX. Maybe QGIS has something similar.

Edits in Oracle Spatial Layers


A Magic Diamond

Question: Place 15 different positive integers on the vertices of this graph so that the ten products of three numbers in a straight line are all equal.
Comment: All ones works, but pretty clearly isn't what you are looking for. Might want to specify that they are distinct.
Comment: Indeed, distinct.
Answer: There are a number of ways to do this. An easy strategy:

 To turn this into a puzzle about addition instead of multiplication, we can solve the addition version of the puzzle and take (for example) 4 to the power of everything.

 So here, I put a magic square in the middle 3x3, and then just pick numbers for the left and right corners so that the remaining four are all different. (This is why I chose 4 instead of 2 as a base: this way, I can use halves, ensuring no conflict between the wings and the center 3x3.)

 The additive solution I found:

 And to turn this into a multiplicative solution, all you have to do is raise 4 to the power of each of the circles.
Comment: What if the smallest possible product is required?
Answer: Here is a solution with a constant product of

 360

which I think is the minimum possible:

Some partial progress for a lower bound on the product:

 First of all, we need a number with at least $15$ divisors: so, nothing less than $120$ will work. But actually, $15$ is not enough. One of the divisors of $n$ is $n$ itself, and that can only be in a triple with $1$ and $1$, which are not distinct, so we can't use $n$. If $p$ divides $n$, then $n/p$ can only be in a triple with $1$ and $p$; if $p^2$ divides $n$, the $n/p^2$ can only be in a triple with $1$ and $p^2$. Such numbers must be the middles of the sides of a triangle, and since they can only be in a triple with $1$, at most two of them can be used. So we need at least $16$ divisors, plus one for every prime factor past the first two, plus one for every prime square factor past the first two.

This leaves only a few possibilities for improvement:

 Of the integers less than $360$, only $240$, $288$, and $336$ pass this test. (Note that if $336$ were possible, then $240$ would be, too: just replace all factors of $7$ with factors of $5$.)
Comment: I have some complicated casework that I'm pretty sure eliminates the smaller products, but I don't think writing it up would be all that exciting to anyone.
Comment: This is also the minimum solution known to me. In mine, all entries are less than 100.
Answer: Edit: In an effort to find the minumum, here is a much smaller solution in which the mutual product is

 $1728$

Solution

As MKBakker pointed out we could further reduce this by dividing each of the entries 4,8,16,96 and 192 by 2 to get a mutual product of

 $864$

although they have subsequently improved on this.
Comment: Nice work. If you divide 192, 16, 4, 8 and 96 all by 2, you get a new solution with all products equal 864. I think we may be able to go lower with reducing the number of repeated prime factors, and including prime factors 5 and 7. But I haven't found a solution yet
Comment: Nice! But this is still not the minimum known to me.
Comment: @MKBakker Nice spot, I had not even noticed that.
Answer: I found a solution trying to minimize prime factors. And finding a balance between the minimum value and minimum number of factors.

 The product of each three numbers is 720

I noticed that some fields are connected, in that multiplying one of them results in the multiplication of fixed other fields. There are three such patterns:
-C, D, H, L, and M (and any mirror image of that)
-A, E, G, L, M (and any mirror image of that)
-A special case is A,B,C, where multiplication of A can be compensated by division of both B and C (Again, also works for the opposite side and the inverse)

Using this, I was able to assign the minimum number of factors required for a unique solution. I think my solution is the lowest possible, but I'm not 100% confident. Perhaps clever rearrangement could lead to another prime factor being reduced.
The solution:

Now it's time for weekend!
Comment: Beautiful, but an even smaller solution is known to me!

A Magic Diamond


I am returning to a company, but I started another company before leaving this one. Is that okay?

Question: I had joined a company and resigned within 4months and served my notice period for a month, after my resignation I joined a new company as a fresher a day prior to my last working day in my previous company. Now I will be rejoining the same company. Will this date of last working day in previous company and date of joining next company affect my rejoining? Is it fine to rejoin ?
Comment: Why wouldn't it be?
Comment: How did you do that? How could you have been at two locations at once? Did you pretend to be sick on that day? Did you use up an unusued vacation day?
Comment: My both companies were in the same location and I had used comp off for one day from previous organisation to join the new company .
Answer:
Will this date of last working day in previous company and date of joining next company affect my rejoining?

This is a matter of what the company decides, and we cannot help you here.

Is it fine to rejoin ?

As long as you left on good terms, why not? I know a guy who left in less than good terms (read: words were said, the kind one does not usually find in dictionaries), and after some negotiation, he was accepted when he returned and everything was fine.
Of course, the company might have a different point of view, and only they know (hopefully) what they will do.
Comment: Thank you , I had completed all the formalities before leaving without any issues and since I was joing as fresher to new company I didn't inform my previous organisation, also I have informed this date overlap issue with the HR assigned to me now. Hope everything goes fine :)


I'm new to ExpressionEngine, for those of you with some experience under your belt

Question: I'm new to ExpressionEngine, for those of you with some experience under your belt ... what are some of the things that you wished you knew when you first got started with EE?
Comment: Despite the fact that many have chimed in with their own experiences here, this question is not within the scope of the site: that is, a question that can have a *correct* answer. ([See the guidelines.](http://expressionengine.stackexchange.com/help/dont-ask))
Comment: I definitely appreciate your explanation of the [on hold] status.  I do think it's a valid question for new EE users, but perhaps the question would've fit better within the guidelines of the EE forum instead of here.  So we can let the question die off a natural death.  To those of you that answered the question ... thank you it helps a great deal and I've bookmarked each site for reference.  Again, thank you.
Answer: It depends on your milage, for me coding was quite new. So, yes, I wished I discovered earlier...:

The videos of Mike Boink http://www.train-ee.com/courseware/free-tutorials (then buy his book)
These podcasts http://ctrlclickcast.com
This website http://devot-ee.com, but be careful there. It is amazing what one can do with EE right out of the box. No need to rush for addons right away.
and last but not least, the art of DRY. And to work systematically. And to make a good plan before even starting. And to have a very good conversation with the client before taking the job.

Did I forget something? Probably yes, but I hope this helps a bit.
Answer: My tips:

Read the user guide.
Read it again
parse order
master config
partials - dry approach
Use Stackexchange forum, past and present posts
Use the debugger and profiler to optimise page load times & minimise number of queries
Use Simple    conditionals    wherever     possible
scratch different parts of your head so you dont get a bald spot!
Answer: I've had a blog post in the works for 2 years with almost exactly the title of your question! You've motivated me to quickly finish it off, update it and publish it:
http://www.jamessmith.co.uk/articles/expressionengine-beginners-guide
Comment: Nice post. Just checked it out. I like it!
Answer: The best thing I can suggest is READ READ READ. Look over the tutorials and examine the sample sites that come with the installs. I got thrown into the mix fast and hard in the beginning and it caused a lot of confusion and a gateway to "bad habits".
Mike Boink was a Godsend in my time of need. He has several tutorials and a good book to get here:
Tutorials
Book
Another great resource of knowledge is Ryan Ireland. He also has some great resources here:
Tutorials
Books
Jae over at http://www.ejaedesign.com/ has great training courses too.
I know there are a ton of people that have helped and that have excellent resources. The entire community is great when it comes to helping each other out. Twitter will become your best friend.


Why is X11 a security risk in servers?

Question: I remember reading that servers do not have a GUI because X11 is a security risk. Why?
Answer: Ubuntu's community documentation explains the real reasons why it's not recommended to run a GUI on a production server system:

Most Ubuntu Server developers do not recommend installing X on a
  server. There are multiple reasons for not installing a GUI.
Some reasons to not install a GUI include:

You'll have more code subject to security vulnerabilities, more packages that need updating, and more server downtime.
X11 and desktop packages are not supported for the full 5 year lifecycle of the LTS server release.
Performance may suffer because resources (memory, hard disk space, CPU, etc.) will be consumed by the GUI.
It is best practice to only install needed software on a production server.
The GUI may include other network services that are inappropriate for a server.

One of the goals of Ubuntu Desktop Edition is to make it easier for users to use Linux. When installing some desktop environments,
  services that you may not specifically want will be installed. For
  example avahi-daemon, which is used to help configure networking,
  adds another open port and may introduce unwanted DNS conflicts with a
  .local domain.

So for the most secure server it is best to not install a GUI.

"ServerGUI" by "Contributors to the Ubuntu documentation wiki", reproduced here as permitted by CC-BY-SA 3.0.
Contrary to somewhat common misconception, X11 being a server really has nothing to do with why running a GUI on a production server is considered to be non-ideal from a security perspective. X11 is virtually never configured by default to be accessible over a network anymore, on any operating system. No version of Ubuntu has ever had X11 run a network-accessible server in the default configuration. (To access X11 on Ubuntu via TCP, you have to forward it though SSH or manually reconfigure the server.)
Furthermore, even if X11 did run a network-accessible server, this would not be a reason not to have it installed on a production server system. Anyone running a production server is presumably capable of configuring it for their needs and auditing it  to make sure undesirable services are not running. (If they cannot, that will pose a far greater threat to their security than would be created by having a GUI installed.) Even if X11 had to have a port listening on a physical network interface (which is not the case), the port could easily be blocked by reconfiguring the built-in netfilter using iptables (or a higher-level frontend like ufw).
In contrast, the problems listed above are not so easy to overcome by reconfiguration.
Comment: 10.04 had a different support lifetime for server vs. desktop, 12.04 and later do not.  Also, an idle gui does not consume any cpu, and the ram it uses will be swapped out.
Comment: @psusi The point about the support lifecycle change is a good one. As for CPU and RAM issues, (1) I disagree from experience that an idle GUI never consumes CPU, and (2) if a GUI is running, then when someone is working at the local machine, they're likely using it, whether they want to or not, and that will cause it to consume more CPU and memory resources. However, points 1, 4, and 5 really are (and probably always have been) the most significant reasons to consider *not* having a GUI run on a production server, and they are independent of support lifecycle or resource utilization issues.
Comment: May I add that Xorg also runs as root by default.
Answer: Every running process is a security risk. Particularly those which listen on a network port (X11 does).
General good practise is not to run anything on a server that doesn't absolutely need to be there, and X11 certainly doesn't need to be on a server that you'll SSH into.
I doubt the article you read was talking about a specific vulnerability in X11 (it would have been fixed if so, vulnerabilities don't tend to hang around unfixed for long), but rather just general good practise.
Comment: On most modern Linux distributions (like Ubuntu) the X server by default doesn't listen on a network port but only accepts local connections via domain sockets.
Comment: Amith: Yes. xinit/startx uses `-nolisten tcp` by default
Comment: @FlorianDiesch Even On the unconfigured one from server?
Comment: Big +1 for mentioning that X11 is a network server.
Answer: This is because the X Window System poses a serious security risk if it is not properly secured. An X11 "display" is the X11 server running on your desktop, and includes the screen, keyboard and mouse. If your X11 display is insecure, it will allow a program running anywhere on the Internet to connect to it and the connection may be completely invisible to you. Once connected, that program has full access to your display, which means that it can:

View and copy your screen's contents, using standard X11 utility
programs;
Monitor your keystrokes;
Remotely control any browser on your desktop and forge keystrokes as if you were typing them yourself (although not all X11 applications are susceptible to this).

A thumb rule is NOT to use xhost + -- It completely disables your display's security.
A good way is to forward X is through ssh.

Taken from : http://www2.slac.stanford.edu/computing/security/xwindow/
Comment: This article is some 10 years old. Is the information still valid?
Comment: Mostly, yes... because AFAIK we have the `xhost +` command
Comment: `xhost +` can't override `-nolisten tcp` though, just open you up to any connection from the localhost.
Comment: would these issues be solved by starting a xserver for each application individually?
Answer: The real reason is so admins can think of themselves as super smart by running stuff from the command line. There is no security risk of running a GUI on Ubuntu server.

Why is X11 a security risk in servers?


Restore and Backup of PS3

Question: I wanted to restore the data on my PSN account on another PS3 to the PS3 I am using now. How is it done? Also I have two more accounts and I don't want to disturb them or delete their data.
Answer: You cannot transfer all data to a PS3 system you are currently using because when you perform a transfer it deletes everything on the destination system, including the other accounts you don't want to disturb.
Game saves can be transfered without erasing the second PS3. To do that you'll need to sign up for the Playstation Plus service and upload all your saves to the cloud using the Save Data Management, then log in on your second PS3 and download those saves.

Restore and Backup of PS3