When is a topological space the homotopy colimit of an open covering?

Question: Suppose that $X$ is a topological space and $\left(U_i \to X\right)$ is an open cover. We can associate to it the Cech diagram of this cover $$C_U:\Delta^{op} \to Top.$$ I know that for many good classes of topological spaces, the homotopy colimit of $C_U$ is $X$ (e.g. for manifolds). How general is this result? Does it hold e.g. for locally contractible spaces? I believe that  In general $X$ is (weakly) homotopy equivalent to the fat geometric realization of $C_U$ (e.g. see Cor. 4.8 here: http://arxiv.org/abs/0907.3925)
 , but for a general simplicial space, this need not agree with hocolim. Any feedback or references would be appreciated. Thanks!
Comment: This is true in particular when the topos-theoretic shape functor $Sh$ agrees with the classical "underlying homotopy type" functor, since it's always true that $Sh(X)$ is the colimit of $Sh(C_U)$. Lurie shows that $Sh(X)$ is weakly equivalent to $X$ when $X$ is paracompact and homotopy equivalent to a CW complex ([Higher Algebra](http://www.math.harvard.edu/~lurie/papers/higheralgebra.pdf), A.1.4). I'm not sure if you can generalize this to "locally contractible". It's not even clear to me that the shape of a contractible space is contractible...
Comment: The answer probably depends on the chosen weak equivalences in $\mathrm{Top}$, right? For homotopy equivalences you probably need a condition like numerable (see the reference to tom Dieck's book in Ronnie Brown's answer). In the same book, Thm 6.7.11 essentially shows that the same thing holds in complete generality for weak homotopy equivalences (as in Marc's answer, but in more classical language).
Comment: Quillen's Theorems A/B are relevant, maybe?
Comment: Well, not only is the shape homotopy invariant (Higher Algebra, A.2.10), but your question is actually answered completely in that appendix, see Remark A.3.8: the functor $Shv(X)\to \infty Gpd$ induced by the "underlying homotopy type" functor preserves all colimits!
Comment: As a follow-up to my first comment, the proof of Lemma A.4.14 in HA shows the following. If $X$ is locally contractible, then $Map(Sh(X),K)\to Map(Sing(X),K)$ is an equivalence provided that the constant sheaf with fiber $K$ is hypercomplete. In particular, $Sing(X)$ and $Sh(X)$ have the same pro-truncated reflections. I suspect they're not the same in general because the usual definition of "locally contractible" for a space corresponds to the topos being "locally $\infty$-connective" rather than actually "locally contractible".
Answer: It is true in complete generality that $X$ is the homotopy colimit of $C_U$ (and hence that the fat realization computes the homotopy colimit in this case). This is a special case of Lurie's version of the Seifert-van Kampen theorem. More precisely, Proposition A.3.2 in Higher Algebra says that that the "underlying homotopy type" functor
$$Sing: Open(X) \to \mathcal{S} $$
is a cosheaf, so it lifts to a colimit-preserving functor $Shv(X) \to \mathcal{S}$. Since $X$ is the colimit of $C_U$ in $Shv(X)$, $Sing(X)$ is the colimit of $Sing(C_U)$ in $\mathcal{S}$.
ETA: The proof of the above result actually shows that $Sing$ is a hypercomplete cosheaf. This reminded me that Dugger and Isaksen also prove this fact in their paper Hypercovers in topology.
Comment: My question http://mathoverflow.net/questions/102295/generalisations-of-the-seifert-van-kampen-theorem is relevant to your comment. Note that this sometimes called "small simplex" theorem has other proofs in the literature, and has not led to proofs of higher Seifert-van Kampen Theorems, to my knowledge.
Comment: I think it would be unfair not to call Lurie's theorem itself a higher Seifert-van Kampen theorem. Note that the result I've quoted is only a special case of *half* of the theorem. The other half (in the same special case) says that the actual colimit of the diagram of simplicial sets $Sing(C_U)$ is weakly equivalent to $Sing(X)$.
Comment: My attitude to Seifer-van Kampen thoerems is that they are about direct computation of a strict homotopical invariant as an exact colimit.
Comment: The invariants I have dealt with are of: spaces with many base points; filtered spaces; and $n$-cubes of spaces. The first two are dealt with in the EMS Tract vol 15 (2011) on "Nonabelian algebraic topology:...", and were published first in 1967 and 1981, respectively.
Answer: Tammo tom Dieck's book "Algebraic topology" (EMS 2008) has  Section 13.2 on the "homotopy colimit of a covering" which you should find relevant.


Should I provide multiple style guides for responsive design?

Question: I am designing a responsive website and wanted to provide the developers with a style guide. But I was wondering if I should provide 2 separate guides, one for the big screen one for the small.
Comment: I'd say provide one style guide that addresses multiple screen sizes. An H1 is this size/font/color/whatever on screens above 1200px wide. At 900px wide it changes to this. At 600px wide... and so on. Or whatever your chosen breakpoints are.
Comment: Agreed, you absolutely want to produce your style guide in it's simplest form. A single document where your product's elements and styles are intuitively presented in harmony is the goal. I would recommend thinking of it as if you are a person who will be absorbing it to understand its content. Clearly section the element variants by the dimensions they're intended for, but present them together so the comparison is clear. Identify what makes the most sense for your product and apply it using minimalist design standards. That's my advice and what has worked for me.
Answer: Regardless of how many guides you provide, they just need to be in the one place that is easily accessible to the developers. The more flexible strategy is to help developers understand how to adapt to different screen sizes, because the layout is only one aspect of responsive design. How the content needs to be adapted for different screen sizes, and how the interaction and behaviour needs to be adapted for different or multiple screens at the same time is just as important as the actual styling of the on screen elements.


Universal Comment Identifier for .NET

Question: What is the most prohibitive aspect of having a universal comment identifier for all .net languages?
For example, in each language the symbol "??" would identify a comment.  (I'm not saying that it should be "??"... just an example.)
Answer: In C#, the '??' operator denotes null coalescence. Repurposing this for comments would render a large amount of code non-operational.
I know you said it's just an example, but this is the problem you're facing - finding a single token that isn't used in any .NET language. I don't think it's a practical goal.
One of the goals of .NET was to allow multiple languages to target the runtime environment, while allowing those languages to retain their own distinction. Your idea runs directly against the grain of this goal.
Answer: I don't really see a point to having a "universal comment identifier" any more than I see a point to unifying the way .NET languages implement looping constructs or class constructors. At some point, you'll be unifying-away the uniqueness of each language and we'll all by writing IL.
Answer: I'd be happy if the universal comment indicator was // ... But then that's because I'm used to c/c++/java/c#. :-) they're the majority anyway, right? ;-)
Answer: Something you might want to look at is Xml comments.  Each language retains it's own comment identifier, but the schema used for the comments is the same across all languages and the compiler for that language knows how to strip them out into an xml file that works with intellisense.
Answer: Backwards compatibility is probably the biggest problem with changing the comment token.

Universal Comment Identifier for .NET


Litecoin implemented MimbleWimble extension blocks. Will Bitcoin adopt this privacy upgrade?

Question: Litecoin is a good real world testcase for upgrades into Bitcoin. With the recent announcement of MimbleWimble extension blocks for privacy on LTC. Will Bitcoin adopt such a feature and what would that impact?
Comment: I'd suggest sticking to asking about the scaling, privacy impact rather speculating on adoption. None of us can tell you if and when a proposal will be merged into Bitcoin.
Answer: It's hard to make predictions about the future, but as of today, nobody has proposed adopting a similar MimbleWimble Extension Block in Bitcoin. Given the skepticism that previous extension block proposals were received with, I would be surprised if such a proposal got significant traction on Bitcoin.

The way I understand the proposal, the MimbleWimble Extension Block (MWEB) is coupled to the on-chain transaction body via a pegging mechanism. Funds can be moved into the MWEB by paying a special on-chain address and withdrawn from the MWEB by effecting a payment from that address.
Inside the extension block, transactions are created via the MimbleWimble protocol. MimbleWimble transactions must be crafted interactively involving both the sender and receiver, but making use Pedersen commitments the values of inputs and outputs are hidden to anyone but the parties crafting the transaction. Immediately after construction, transaction inputs and outputs form a similar graph structure as on-chain Bitcoin transactions. However, the minimal MimbleWimble transactions are especially designed to allow for transaction cut-through: transactions can be aggregated non-interactively facilitated by some Elliptic Curve magic and due to Pedersen Commitments being homomorphic, which prunes any intermediate outputs that already got spent in the aggregate. (E.g. if there are two transactions (A1⇒B1+A2) and (A2⇒C1+A3) they could get aggregated to (A1⇒B1+C1+A3) pruning the creation and spending of output A2.) As MimbleWimble transactions can be aggregated even across blocks, the chainstate reduces to a remaining kernel per transaction, the peg-in inputs and the currently spendable outputs. On the downside, MimbleWimble transactions are very limited in their scripting capabilities.
In result, an attacker can learn more about the transaction graph by actively monitoring the transaction relay, but a passive monitor catching up later would effectively only see a huge coinjoin that is the aggregate effect of all previous transactions with hidden amounts.

I only skimmed the MWEB proposal to brush up on details. I suggest verifying any information in this post if you have more than a passing interest.
Comment: MW is great but it's biggest downside is that the transactions are interactive which means that sender and recipient's wallets need to communicate in order to complete the transaction.


Drilling a new hole and putting threads in it for a bolt to screw in

Question: Hi everyone (noob alert)- I need to put a threaded bolt into a fresh new hole I have drilled into a piece of metal but how do I put in threads which match this particular bolt?
Thanks
Comment: So how is this motor vehicle related @MathNYYB? I'm not being pedantic, it's about understanding the overall thing you are trying to achieve, otherwise you might not get the answers you really need. What is this actually for?
Comment: What is the purpose of the hole? What material is it you want to thread?
Comment: it's a block of very thick steel. a small hole not too big at all.
Comment: Seems like this would've been more appropriate on: http://diy.stackexchange.com/
Comment: How thick is the "piece of metal". What is the size of the "piece of metal"? Is the "piece of metal" permanently attached to something (like a car) or is it a freestanding thing that can be moved?
Answer: Making threads is done with two tools known as a Tap and a Die.  The are sold individually or in sets.  To make threads in a hole, you need a tap.  Those are the items in the image that look like a cross between a bolt and a drill bit.  In fact, that's what they are.  As you use the handle to turn them into the hole, the tapered flutes cut threads into the walls.
Note that each tap size needs a very particular hole size, and many are sold with matching drill bits because some sizes are just a little different than the typical set of drill bits will contain.
Also, each size will have a minimum thickness.  These are not for use in sheetmetal.  The metal needs to be thick enough to have at least a few threads cut into it or the bolt would easily rip out.  The thickness needed depends on the bolt size and the strength requirements.
The dies (plural spelling?) are the circular pieces and they are used for making threads on the outside of a bar (to make a bolt).
Using these tools takes a little practice and some patience.  Its possible to break a tap off inside a hole, and then you have a tough situation.
Comment: Also look very carefully at the taps in the image - the tap on the rhs is a botoming tap to finish the thread to the depth of the hole , the other three are "starting" taps to start the thread ...
Comment: you can't emphasize the practice part enough.  It is practically guaranteed a newbie will break at least one tap while learning (especially a the smaller sizes and especially going into steel).
Comment: @agentp That's true, and I would suggest the OP learn more about it and practice on scrap first.
Answer: The tap & die answer is accurate, and as for your concerns about the threads matching, maybe this will help you choose the correct thread type/count so it should be no issue. Threads for screws, bolts and nuts vary due to type & intended application and are very precise. Dies and taps have a numerical indicator on them revealing the size and thread count they are gauged at. Lower thread count=less ridges per inch and a "looser" thread pattern, higher count= "tighter" pattern and more ridges per inch, and these are standardized across the industries that utilize these fasteners. Your bolt`s size and thread count are easily measured/verified, making matching it to your needed tap tool just as easy, and being standardized means you can buy the tap you need from any who sell tap & die equipment and be assured an accurate fit.


What program to follow if I have a lifting competition in 4 week?

Question: I am novice gym goer and even though my lifts are very beginning-intermidiate level,I am wondering what type of training should I do to prepare for the event.My weight is 62kg at 5'6" and my squat and bench are relatively weak compared to DL I think. Here's my numbers :
Back Squat 100kg.
DL 155kg.
Bench 75kg.
Comment: Edited,it's a squat,bench and DL comp.
Comment: Are the weights that you list you one rep maxes? Or do you lift those for multiple reps?
Comment: One rep,that's what I'd have to do in the event too.
Answer: Four weeks is not a lot of time to prepare for a meet, but you can do some training to improve your performance.
First, don't worry about the differences in your lifts. Focus on making the biggest increases in weight that you can, without worrying which lifts the increases occur in. If you can add either 10kg to your deadlift or 2.5kg to your bench press, then adding 10kg will give you a better result in the competition.
Second, practice performing high intensity single reps. Add these to every workout. For example, if you would normally squat 3 sets of 5 at 80kg, instead, on your first workout, try adding a single at 90kg before your 3x5 sets. Then on your next workout, try a single at 95kg before your 3x5 sets. Keep increasing the weight on the singles workout by workout until they become difficult. And make sure you have safety bars set up in case you fail.
Third, practice your lifts in the same way that they will be performed in the competition. The most likely difference will be the bench press, where in powerlifting competitions you generally are required to wait for a command to begin, lower the bar to your chest and hold it still, wait for a command to press, and only then lift the bar. You need to get used to pausing at the bottom of the bench press like this, and if you have someone in your gym who can give you the commands while you lift, then that's even better.
Fourth, back off your training at least a few days before the competition. This is called a "deload" period and allows you to fully recover before the meet. A week would be normal, in which you might only do a low volume of training at your normal intensity, but since you only have a month to prepare, maybe you should reduce that to 4 days. For example, instead of a single rep at 95% of your one rep max and then 3x5 at 80%, you might do one rep at 90% and then one set of five at 80%.
Fifth, have a strategy for the meet. If it's run as a typical powerlifting meet, then you will have three attempts at each lift. A common strategy is to begin each of the three lifts with a weight that you could confidently lift for three reps. This is to ensure that you don't accidentally fail all three attempts, which would disqualify you from the competition. (Remember, if you miss an attempt, you can re-attempt with the same weight or heavier, but you can't request a lower weight.) Then on your second attempt, choose a weight that you are reasonably confident that you can lift for a single. Then if you succeed on that attempt, observe how difficult it was, and decide how much heavier you think you could go for your third attempt. E.g. You might choose 95kg for your first squat attempt, then 102.5kg for your second. If you get the 102.5 and it feels reasonably easy, you might try for 107.5kg on your final attempt, or if it felt difficult then only increase to 105kg for the third.


how to determine correct sample size?

Question: I have 2,000 transactions and I have to check the accuracy of those transactions. I want to select a sample, check all transactions in this sample and make conclusions on population with 95 percent of confidence level. is there any formula for selecting the correct sample size? Please also give me advice about how to make a conclusion on the population.
Comment: What exactly does it mean for a transaction to be accurate? Defining this will go a long way towards answering your question.
Comment: In addition to the question that @Dave asks, what fraction of transactions do you expect to be inaccurate, and how narrow do you need your 95% CI to be? For example, if you expect 5% to be inaccurate, would 95% CI of 1%-9% be adequate, or do you need something tighter like 4%-6%?
Comment: in my case accurate means that all parameters of transactions were specified correctly.  inaccurate means at least one parameter in transaction is incorrect. @EdM  I have no idea how much of transaction are accurate. confidence interval of 1-9 % would be adequate.
Answer: What you have is a set of transactions, each of which is either accurate or inaccurate. Each binary inaccurate/accurate observation can be considered a Bernoulli trial. If this status of each transaction is independent of the others and each has the same probability of being inaccurate, then a set of such observations follows a binomial distribution. There are several approaches to estimating confidence intervals in this situation, explained on this Wikipedia page and this Cross Validated page.
The size of the sample you will need depends both on the fraction of inaccurate transactions and on how tight you want the "confidence level" to be. As you have no idea about the fraction of inaccurate cases to start, I recommend playing with the Jeffreys credible interval, based on the beta distribution, to get an idea of what will be involved. The credible intervals produced by such a Bayesian approach can more readily agree with intuition about "confidence levels" than the confidence intervals provided by standard frequentist analysis, and the Jeffreys interval "has good frequentist properties" too, as the Wikipedia page puts it.
This Shiny app can provide a useful graphical display of Jeffreys credible intervals for this situation. Choose the Jeffreys prior option, the credible level you want, and your choice of number of transactions observed and the number of "successes." (I'd recommend calling an inaccurate transaction a "success" but that is up to you.) The app then shows the estimated distribution of success probability values and the credible interval.
For example, say you analyze 50 randomly sampled transactions. If you find none inaccurate, that app provides a 95% credible interval for the fraction of inaccurate cases of [0, 0.049]. If you find 6 inaccurate,  the interval is [0.052, 0.231]. If you find 20, the interval is [0.273, 0.538]. Playing with different possibilities will point the way forward as you start to analyze these cases. My guess is that if you sample about 50 transactions to start you will get a reasonable idea about the inaccuracy probability and the number of observations needed to get a narrow enough credible interval to meet your needs.

how to determine correct sample size?


Given the hash of a collection, H(X), can I build a proof that F(X) == Y, without having X?

Question: Given a cryptographic fingerprint of a collection, K == hash(X), an arbitrary function F, and a value Y, is it possible to build a short proof that F(X) == Y that doesn't require having X? I.e., a proof that Y is the result of applying F to some X such that hash(X) == K?
Comment: I find this question confusing
Comment: Do you mean a proof that can be *generated* having only Y but not X, or a proof that can be *verified* without requiring X to be known and without revealing more about X than F(X)=Y does? (It is unavoidable to reveal some information about X, namely the fact that F(X)=Y, which e.g. when F is a bijection with a feasibly computable inverse degenerates to revealing X.) Are you asking about an interactive proof, or about a static proof?
Comment: @Gilles the later (*"a proof that can be verified without requiring X to be known and without revealing more about X than F(X)=Y does"*).  I'm asking about a static, non-interactive proof.
Answer: Yes, this is possible.  Use a zero knowledge proof (of knowledge).  If F is computable in polynomial time, then there exists a polynomial-time zero-knowledge proof of the property you want, i.e., given K,Y, the prover can construct a proof that there exists X such that H(X)=K and F(X)=Y.  Amazingly, this proof is "zero-knowledge": it reveals nothing about X (other than the property is true).
If you don't care about the zero knowledge part, you can just use an interactive proof system.
Zero-knowledge proofs can be made non-interactive using standard techniques.
There's tons of work on this in the cryptographic research literature.  I can't explain the ideas in the length of an answer here, so I suggest you spend some quality time studying this material.  However, while the theory is elegant and beautiful, you're probably going to find the generic schemes are not very practical and the performance overhead is significant.  Therefore, if you actually want to do this in practice, you'll want to focus on a specific function F and see whether you can build a custom protocol specialized to that particular function F.
Answer: The principle of a hash function is that multiple, different values can hash to the same key. The complexity of the hashing function determines how many possible values X may have. Consequentially it becomes impossible to prove that F(X) == Y if Y is a single value. After all, if X can be either 2 or 3 and F(X) = 2*X then Y is both 4 and 6.
If F(X) is considered to be a set of possible solutions then you only have to prove that your given value 'Y' is a member of this set. The actual value of X is not a requirement to solve this problem and therefore it is possible to prove.
Comment: I suspect MaiaVictor is considering the case of a *cryptographic* hash function, and considering only adversaries who are computationally limited, so we can effectively assume that no one can find any collision.  Or, if you prefer, think of it as a cryptographic commitment rather than a hash (there exist commitment schemes that are perfectly binding and thus have no collisions).  Consequently, I don't think this answers the question that MaiaVictor probably intended to ask.  I agree this should have been clearer in the question.


Standard Process Identification of New Disease outbreak Causing Pathogen

Question: Is the any standard procedure or protocol followed for the identification of cause of new disease outbreak(or new pathogen)? Is it different for different countries?
Comment: I am not sure **if** there is any standard method for this. You find a patient with an unknown disease. Than you try to find out, what is going on. Isolate body fluids, analyze them and so on. Depending on the reason the methods are different.
Comment: I won't post it as an answer because of the 'human-biology' tag but this paper describes the process by which Schmallenberg virus was recently(ish) detected in Europe: syndromic surveillance picked up the disease, and NGS identified the agent. http://wwwnc.cdc.gov/eid/article/18/3/11-1905_article
Answer: I was first thinking of voting to close the question because it was too broad, but in reconsideration I think the answer of showing why it is too broad would constitute a proper answer in this case.
First of all, the term disease is one of the most general terms for a problem in medicine.  The only term that could be higher up is "medical condition."  It could be an infectious disease, genetic disease, induced disease (think chemicals, tobacco, etc), or [insert organ here, ie heart] disease (which are not necessarily genetic).  There are attempts to distinguish between "diseases" and "disorders," but the difference is not always clear.  The term "disorder" is growing in usage and scope because it is seen as having fewer negative connotations than disease (think disease of the mind vs. disorder of the mind).
Thus each field has it's own ways of identifying new diseases.  As a general trend new diseases are found now by identifying greater specificity within a previously general disease.  For example, a person could be said to have an "adrenal cancer," but now we would want to know if they have an adrenocortical carcinoma.  In an infectious setting, we could think of all the particular pneumonia being specified out of interstitial lung diseases.
Diseases caused by external agents (pathogens, toxins, etc) can sometimes be more uniquely novel, in that they can change into something unpredicted (new compound or virus made by man for example).  Perhaps you meant to ask if there were standard ways for identifying new viruses or microbes?
Comment: Can you change your answer now?
Comment: @DevashishDas. Sorry to be slow on this.  My participation in the site is very intermittent, and I'm not checking anywhere for notices.  I think Benz has a good awnser, with my only additional thoughts being arrays currently under development to gage if the host response is to a viral or bacterial infection.
Answer: Pathogen identification procedure is not necessarily standardised due to differences in resources available to each country but there are certainly several characterised and accepted approaches used to identify a disease causing pathogen. The predominant techniques used to identify pathogens relies upon conventional clinical microbiology-based approaches, which has been highlighted in the comments above. However these conventional techniques such as standard culture and susceptibility tests have many drawbacks such as time-consuption and lack of scalability in addition to lack of direct characterisation of virulence factors. Most pathogen (except prions) logically carry a unique DNA or RNA signatures that differentiate it from other organisms, which provides the basis for disease causing pathogen characterisation. According to this page there are two approaches used to detect a pathogen, once sampling has taken place.
1) qPCR based pathogen detection: allowing sensitive and real-time detection of genetic signatures, which is not currently matched by sensors such as immune-assay techniques (lagging in detection time, logistics and costing) and optical techniques (lacking specificity).
2) Microarray based pathogen detection: allowing combination of nucleic acid amplification (offered by PCR based techniques) combined with massive screening capability of microarray technology, resulting in high level of sensitivity, specificity, and throughput.
These techniques are obviously combined with powerful software technologies required to sieve through the data and allow for easing of experimental burden, minimising assay development as well as operational costs. Now clearly these techniques including sensors and conventional microbiology are used concurrently/synergistically to more efficiently identify a disease causing pathogen and strategies a treatment/preventative measure. This review nicely illustrates the molecular basis for pathogen identification and discusses general considerations (in this case for fungus detection) such as DNA extraction methods, sampling preparations and strategies and goes on to highlight some other sequencing independent methods such as FISH and macroarray.
This paper writes about sequencing based strategies and using the BLAST (NCBI) tool and talks about identification of variant strains of known species, identification of non-cultivatable pathogens and more importantly related to this question, identification of new species using (rDNA) phylogenetic trees of bacterial 16S gene and the fungal 18S gene, commonly used for this type of analysis. This is done in order to determine the phylogenetic position of a the suspected new species compared to a closely known related species, which is useful when there is a <98% of the sequence similarity with known species.


Can a Mac Pro be upgraded from a 5150 CPU to a 5365?

Question: Is it possible to upgrade a first-generation 2.66 Ghz 2-core Mac Pro (Woodcrest) to a faster model by replacing the CPUs? I've read that some Mac Pro models shipped with 3 Ghz 4-core Xeons (Clovertown).
Answer: Yes, you can but only with Intel Xeon E53xx,  X53xx or L53xx series processors that have a LGA 771 socket.
Although one word of warning,  the supported OS upgrade life time of the Mac Pro 1,1 and 2,1 looks like its coming to an end. Apple as we have seen in the news is prepping for Mountain Lion, and dropping support for all macs that lack a 64bit EFI. So it appears highly likely that Mac OS X 10.7 is the last OS you will be able to run on these Mac Pros, unfortunately. Be aware of that when prepping for your Mac Pro 1,1 and Mac Pro 2,1 upgrade plans, especially if keeping current is a priority of yours.
That said, now on to the upgrades:
The Mac Pro original Upgrade process
Here are processor upgrades that people have completed and confirmed in Geekbench as working, see their results below.
MacPros using L53xx Xeon processors.
MacPros using E53xx Xeon processors.
MacPros using X53xx Xeon processors.
Answer: Yep. Anand even did it when the Mac Pro first came out. I've seen other reports too.
Comment: No go for portables. The processors are soldered onto the motherboard. In order to save space... Besides, people who buy Macs don't upgrade their processors, it's a very small market, so why would Apple waste time adding the possibility to their portables...
Comment: What about a MBP?
Comment: Also, the CPU is only one component of a main logic board, simply upgrading it won't necessarily work with the older chipsets required to control power, i/o, memory, etc.. Better to upgrade the entire system and downcycle the older system to somebody else (great resale market for used, good condition Macs).
Answer: Found out that a company does processor upgrades, but for some Mac pro models only. Perhaps yours is eligible:
http://eshop.macsales.com/shop/turnkey/MacPro/2010_Xeon_Processor
And also this forum about upgrading a first gen Mac pro:
http://forums.macnn.com/65/mac-desktops/452598/macpro1-1-processor-upgrades-1st-generation/#post4130757
Answer: I've just done this upgrade to a used Mac Pro 1,1. I bought two X5465 CPU on eBay from China (production Costa Rica) and they installed fine with heat around 40 degrees at idle and 50 degrees under full benchmark testing with Open CL Sala room test (CPU). I did use very good heat paste though after thoroughly cleaning the processors.
I want to run Snow Leopard so I'm not bothered about the 64 bit EFI. But if I was, the computer when I bought it was running Yosemite using Piker's bootloader (just puts in some translation files in boot.efi which thunk the 64 bit calls onto the 32 bit firmware). No problem running even high end graphics like Borderlands 2 on Steam on a Nvidia GTX 580. If you plan to game, though, I don't recommend the Mac Pro 1,1 as it has only a PCI Express 1 (maximum bandwidth 2.5 GB/sec) which hobbles high end cards (higher than Radeon 5770 or GTX 285).
I'm not going to follow my own advice and I'm dropping in a Radeon 5870 as there is an improvement especially for FCPX and apparently the 5870 is quieter. Price difference these days is more like $50 and not $200 between the 5770 and 5870.
Even the Nvidia 7300 GT runs fine and absolutely silent. It does choke a bit when trying full screen video playback with both 30 inch and 24 inch monitors attached.
As work computers (as opposed to Da Vinci Resolve 12 colour correction suites or high end gaming rigs), the Mac Pro 1,1 is an amazing silent and powerful performer. I suspect these elegant silver towers will still be in service when people tire of black trash cans without slots for cards or drives.


categorizing articles using deep learning

Question: Is it possible to write a program using deep learning that categorizes an article (news, entertainment,..., etc. ) into a positive category or negative category based on a specific theme?
Comment: Do you want to tag articles according to topics?
Comment: According to the material. For example, if I pic a subject let say trump, al gore etc. (I'm thinking to use this for people mostly) I want for the program to scan through as many recently article written about them as possible and tell me if the stories are positive or negative and the topic the story is about. Also would like to visuals this data.
Answer: Yes, this is classic sentiment analysis. You'll need training data in order to write this program.
Typically, people will build a language modeling using the text data in the article, tweets, posts, etc. Most folks specify the language model using a Recurrent Neural Network with a Long Short Term Memory. Here's a blog post that has code linked to their github.
Before diving into a more advanced deep neural network like an LSTM, it may be easier to start with a multilayer perceptron using n-grams.
It seems like you may be asking for a couple of different things. So, let me be very explicit. The models I listed above take as input the articles and a label that evaluated the articles as either positive or negative sentiment, the model then returns the likelihood of a given article being positive or negative sentiment. It in no way returns a topic.
To return the "topic" your best bet would be to run Latent Dirichlet Allocation, which would then return the likelihood of a given article being generated from a given topic that was previously learned. It's important to note that these will only be from topics learned on previous training data and not on new topics.
There are standard algorithms available to visualize topic models (e.g., LDAVis) and the embeddings of language models (e.g., word2vec visualizations).
It's worth noting that there is research being done in learning these items jointly (i.e., the latent topic and the classification of good/bad). I'd recommend reviewing this paper.
It may be worth reviewing these items more thoroughly before actually diving into applying them. It sounds like you may not have a complete picture of what your goal is and how deep learning can help you.
Comment: Worth adding that LSTMs need a lot of training data in order to out-perform simpler models such as bag-of-words plus classifier (e.g. logistic regression or SVM). As the OP is clearly just beginning to explore possible solutions, start with a simpler option rather than jumping straight to state-of-the-art.
Comment: @NeilSlater Thanks for the useufl comment. I thought about stating that before too but I also noticed he explicitly asked for "deep learning". I've updated my response to mention a simpler neural network.
Comment: No problem. There is no need to flag edits or updates in your answer, as the site will keep revisions, and the Q&A will bump to the top of the default list when you make a change. Just aim for a well-written answer, assuming some visitor finds it later on.


Will I lose my phone number and phone plan with factory reset?

Question: Will I lose my phone number or phone plan if I reset my Android to factory settings? I know I will lose my pictures, contacts, and stuff but those I can get back.
Answer: No. Factory reset erases data stored on /data partition of your phone. It includes your preferences (what you set in Settings app), user apps and their settings/data, system apps' settings/data (including contacts and messages) and personal data stored on /sdcard including pictures, videos and some apps' data (like WhatsApp stores media and messages backup on /sdcard).
But phone number is just an id (MSISDN) mapped to International Mobile Subscriber Identity (IMSI) which is assigned by Mobile Network Operator (MNO) to your Universal Integrated Circuit Card (UICC; SIM/USIM) on GSM/UMTS/LTE networks or (CSIM/RUIM on) CDMA network, or to phone (identified by its ESN; Electronic Serial Number, compared to IMEI on GSM) on pre-3G CDMA network. This isn't something stored on your phone, it's your account's detail which is stored on your service provider's system.
eSIM is the UICC embedded inside phone (not considering iUICC or virtual/dummy SIM or pure software SIM) which is programmable so that you don't need to swap SIM cards. eSIM stores one or more profiles which hold essentially the same information as a physical SIM card - including ICCID, IMSI (MCC/MNC tuple + MSIN) etc. - which is linked to possibly multiple changeable MSISDNs (phone numbers we dial). And just like hardware SIM, eSIM is Secure Element, completely isolated from Android OS, even the processor. So it's not affected with any filesystem changes. If factory reset erases profiles intentionally, those can be re-programmed. All that's needed is the unique QR code which, if lost, can be obtained from MNO or even their apps can generate. So your phone number isn't affected.
Similarly your call/message/data plans are associated to your identity (phone number). You will be able to avail those services as long as you have a valid subscription and your SIM card is inserted in a compatible phone, identifiable and authentic-able by the MNO.
Comment: Note: This answer was written for a device that does not have or not use the eSIM functionality. When using an eSIM the factory reset can/may erase the phone number as well.
Comment: @Robert factory reset won't erase phone number, but just the eSIM profile. Which you can add/delete as many times as you want. All that's needed is the unique code from MNO. If the code is lost, it can be obtained from MNO or even their apps can generate.
Answer: The quick answer is "No, it doesn't effect your plan or phone number".
Note: Factory reset  is just a clean up process which includes permissions to clean and reset everything within device to it's factory made stage. Of course you have additional options to clean your SD card and sim contacts too, if you want.


What this page means for the Debian's package version

Question: I am trying to figure out what these web page means for the version. I know that the epoch is the number previous the double dot. But I can't figure out what this all means ?

I found this here
Answer: As you noted, the epoch is the number in front of a colon, specifically used in Debian pacakges.
If the scheme of upstream package version changes or if there was an error
with an upload, the epoch of a package can be increased to remain a consistent ordering of packages with different versions, which is e.g. important at any system update.
The page you found just lists the security reports with a wrong/missing epochs. This happens when the current epoch of a package was not used when entering the versions of the package in which a security problem was solved.
These are database inconsistencies, which are requested to be solved. The effect is that the affected security problems could be wrongly marked as solved in too early package versions.


A question on morality

Question: As I understand it, we carry out generous and selfless deeds for the purpose of acquiring positive kamma and/or promoting our spiritual quest. However, this seems like a form of greed, one of the three unwholesome roots (I think that's what it is labeled as, unsure). How can moral acts be qualified as free of greed, when it seems that the motive for morality is ultimately self-gain (greed)?
Answer: Your question might be considered a mixture of asking about sila (morality) and dana (giving). The reasons for doing each are a little different.
The most basic reason for acting with sila is to prevent remorse at our own wrongdoings which would make samadhi (concentration or meditation practice) far more difficult. Being able to practice proper samadhi leads to panna (wisdom). Sila, samadhi, and panna are all intricately connected and the whole thing breaks down when one is filled with remorse at wrong doing.
You should be interested in your own enlightenment. From What Buddhist Believe, by Dr. K. Sri Dhammanada. (page 266-267)

You Have to Save Yourself
ONESELF, indeed, is one's saviour, for what other saviour
  would there be? With oneself well controlled the problem
  of looking for an external saviour is solved.
  (DHAMMAPADA 166)
As the Buddha was about to pass away, His disciples came from
  everywhere to be near Him. While the other disciples were constantly
  at His side and in deep sorrow over the impending loss of their
  Master, a monk named Attadatta went into his cell and practised
  meditation. The other monks, thinking that he was unconcerned
  about the welfare of the Buddha, were upset and reported the matter
  to Him. The monk, however, addressed the Buddha thus, 'Lord as
  the Blessed One would be passing away soon, I thought the best way
  to honour the Blessed One would be by attaining Arahantship
  during the lifetime of the Blessed One itself'. The Buddha praised
  his attitude and his conduct and said that one's spiritual welfare
  should not be abandoned for the sake of others.
  In this story is illustrated one of the most important aspects of
  Buddhism. A person must constantly be on the alert to seek his or
  her own deliverance from Samsara, and 'salvation' must be brought
  about by the individual alone. One cannot look to any external
  force or agency for help to attain Nirvana.

Working towards our own enlightenment is clearly acceptable and expected.
The most basic reason for acting with generosity, is to reduce our own greed or attachment to our own resources. If we cling to anything, we suffer. If we give with wholesome intentions, we reduce our clinging to our own resources which reduces our suffering. That's different than giving with the expectation of receiving a good kammic effect in return. There are good kammic effects connected with acts taken with wholesome intentions, but we don't know the timetable on receipt of such kammic fruits. It could be a long way off.
So we do good things because it's good for our mind states, which is good for our eventual enlightenment. The importance of creating the conditions for our own enlightenment was stressed by the Buddha among his last words.
Comment: Thanks for the response, it's great- thorough and definitely answers my question!
Answer: I think we're supposed to distinguish between wholesome and unwholesome desire.
I think the word for greed or unwholesome desire is Taṇhā (literally "thirst"). The Wikipedia article says,

Contrast to wholesome desire (chanda)
The Buddhist teachings contrast the reflexive, self-centered desire of taṇhā with wholesome types of desire, such as the desire to benefit others or the desire to follow the Buddhist path.[c] Wholesome types of desire are traditionally identified as chanda.[20][21][d]
Ajahn Sucitto states:

Sometimes taṇhā is translated as "desire," but that gives rise to some crucial misinterpretations with reference to the way of Liberation. As we shall see, some form of desire is essential in order to aspire to, and persist in, cultivating the path out of dukkha. Desire as an eagerness to offer, to commit, to apply oneself to meditation, is called chanda. It's a psychological "yes," a choice, not a pathology. In fact, you could summarize Dhamma training as the transformation of taṇhā into chanda. It's a process whereby we guide volition, grab and hold on to the steering wheel, and travel with clarity toward our deeper well-being. So we're not trying to get rid of desire (which would take another kind of desire, wouldn't it). Instead, we are trying to transmute it, take it out of the shadow of gratification and need, and use its aspiration and vigor to bring us into light and clarity.[20]

I suppose a poor analogy might be that drinking (alcohol) isn't wholesome, but that drinking water is beneficial.
There's also a sutta on the subject: Brahmana Sutta.

It's also two different objects:

Not being generous implies accumulating wealth for selfish ends (which doesn't make you happy)
Whereas being generous implies helping other people (which does make you happy)

So they're not entirely the same thing; if it is "a form of greed" at least it's not the same form.

Also this description of generosity says that "stinginess" is a "stain". Presumably generosity then is the opposite.
Although the Zen story Mokusen's Hand implies that lay householders should aim for some medium.
Answer: Dhamma Greetings Ian,
it works anyway.
The two things having influence on what will happen to you in the future are the deed itself and the intention you have in your heart/mind while doing it.
The action determines the kind of Kamma-Vipaka and the intention has influence on how strong it will be.
So, if you do good with selfish intention, it will not come back onto you as good as it will if you're just having fun doing good things.
Hope this helps and please correct me, if I am wrong ;-)
Be Well

A question on morality


What is the function of the power button on the Apple Wireless Keyboard?

Question: What does the power button on the Apple Wireless Keyboard do? When it is paired to a MacBook in clamshell mode, does pushing the power button put the MacBook to sleep, wake it up, or have some other effect? Is the power button strictly limited to turning on and off the keyboard itself?
Answer: The power button only powers ON/OFF the keyboard, it doesn't power off the computer.
To power off your computer using the keyboard, you might want to use any of the following:
Reference:

⌘ (Command key) - On some Apple keyboards, this key also has an Apple logo ()
⌃ (Control key)
⌥ (Option key) - "Alt" may also appear on this key
⏏ (Eject)
⇧ (Shift)

⌃ Control + ⏏ Eject : Show shutdown dialog
⌥ Option + ⌘ Command + ⏏ Eject : Put the computer to sleep
⌃ Control + ⌘ Command + ⏏ Eject : Quit all applications (after giving you a chance to save changes to open documents), then restart the computer.
⌃ Control + ⌥ Option + ⌘ Command + ⏏ Eject : Quit all applications (after giving you a chance to save changes to open documents), then shut down the computer.
⇧ Shift + ⌃ Control + ⏏ Eject : Sleep the display, but not the computer.  (thanks to VxJasonxV)
Comment: @Josh those sure took some time! I believe I'm gonna put a feature request for a toolbar :)
Comment: See I marked this question as a favorite and intend to come back here and copy from your answer whenever I need keyboard tags XD
Comment: @Josh I'm honored :) You can always google for these, but at least we have them here. Surprisingly, they look "bad" on Safari. We'll have to talk with Jeff…
Comment: One more helpful one: Shift + Control + Eject = sleep display, NOT computer. I use that as a Windows + L (lock screen) equivalent in Mac.
Comment: An easier way (imho) to lock the screen is to set up magic corners. I always use lower left corner to make the screen sleep "Windows + L"ish.
Answer:
Is the power button strictly limited
  to turning on and off the keyboard
  itself?

Yep. The wireless keyboard software detects inactivity and will go in sleep mode where it reduces power consumption, however it's probably better to turn it off if you know you won't be using it for a while. You must press that button for a few seconds. The light will show, then it will disappear while you are still holding the button. Then you know it is off.
When you turn it off that way it should display a notification on the OS X desktop, that the bluetooth device was turned off.
I'm not using one anymore. When I did, I would often forget to switch off the keyboard.
Now that I think of it it would be nice if there was an option for the computer to tell the keyboard to power off. That way when you shut down your Mac it would power off. I don't remember seeing such an option :(


Hook for altering secondary local tasks

Question: hook_menu_local_tasks() works for the top level tabs, but the secondary tabs don't seem to have an equivalent. Does anyone know how I can modify those?
Comment: There is no hook such as `hook_menu_local_tasks()`.
Answer: $primary = menu_local_tasks(0);

$secondary = menu_local_tasks(1);

See: http://api.drupal.org/api/drupal/includes%21menu.inc/function/menu_local_tasks/7
It's actually not a hook, it's just a function that gathers the items while in context.
There is a hook to alter the items: http://api.drupal.org/api/drupal/modules%21system%21system.api.php/function/hook_menu_local_tasks_alter/7

Hook for altering secondary local tasks


Replacing gas burner in a vented glass 3 sided fireplave

Question: Our fireplace, installed in mid 80's has a burner that is completly worn out. Is is possible to install a new burner that is not made by original maker? When I've asked at fireplace shops they claim that the entire unit, box and all must be torn out and replaced...really? I want to know if I can purchase a burner and replace, if so is there anything other than where the burner connects to gas line I need to know an
Bout? Thanks
Comment: I think for liability reasons if not a direct replacement the store may say everything needs to be replaced. Is the original MFG still in business? Contacting them you may be able to purchase a new burner or find one with a similar design and BTU rating to replace the worn out one.
Answer: You must get a new burner from the manufacturer, anything else could potentially end in disaster.remember to make sure if it's natural or propane gas burner.


How closely correlated is culture to geography?

Question: I am working on a story where I will take the geography of our world but install new peoples, cultures and histories.  This will likely include fantastical elements as well as mundane.  In working through this I have started with the base topographical map of the location I am working through and then began to paint in the cities and states of the groups I'll be writing about.  In thinking of where the cities will be located and the backgrounds of those places I begin to wonder exactly how much I will need to look to our own history as a guide.  As geography is paramount to where we have settled and why we have settled there, in addition to often also framing the narratives we tell ourselves about those locations and in turn shaping the cultures that grew around those narratives, how much credence should be placed on the existing cultures and histories of our own world when using the geography of Earth as a template for a fictional peoples set in the same location?
Comment: Look up Guns, Germs, and Steel by Jared Diamond for the answer to this question. There's a book and a documentary on youtube.
Comment: @Shadow1024 you need to read the book again, it claims none of those things. For one wheat is one of the highest yield crops in existence. It also does not come from europe.
Comment: While reading Guns, Germs and Steel, remember that according to the hypothesis of this book Europeans got the crops of lowest yield (wheat) thus were doomed to be outnumbered and squashed by either East Asians (rice) or Native American (corn, potatoes), thus some degree of scepticism is recommended ;) BTW: How deep are you going? Are you interested in answer considering pattern of prehistoric migration? (or that would be an overkill?)
Comment: To be precise: JD claimed strong geographical determinism, based on available species, and I'm just pointing out where his whole hypothesis starts to collapse. Issue of wheat being inferior crop in comparison to staple crops available to other civilisations, he accidentally overlooked. (for our climate potato produces roughly twice higher yield) John, if you mentioned that... yes, wheat comes from the Fertile Crescent, so if we follow JD hypothesis Europeans were even more doomed, as it requires almost impossible (at leas according to JD) adaptation towards different climate on NS axis.
Comment: Are you making stuff up completely, or are you positing alternate timelines with a distant history shared with our world?
Comment: The geography, climate, etc. will be the same but the nations, cities, etc will be made up.  There may be some corollaries to real peoples/places but in general it will be entirely fictional.
Comment: I would certainly be interested in such an answer.  I am planning on building the world as is and working backward writing the history behind those civilizations.  I want the world to feel lived in.  Since I am using our world as a template, information about how the geography would have influenced the way that we came to be placed, why we are there and the stories we told ourselves is pertinent  and useful.
Comment: In addition to Guns, Germs, & Steel, I would also recommend [The Revenge of Geography](https://www.goodreads.com/book/show/13330422-the-revenge-of-geography) by Robert D. Kaplan.
Comment: too many variables, location is not the key to culture
Comment: @Shadow1024 What?!  You may need to read the book again.
Answer: Let's try some examples.

The Italians live in the exact same geography where the Romans lived. The Romans built a great empire which endured for a long time, and has greatly influenced legal and political systems throughout the world to this day. The Italians spent a full millennium divided into many small states waging funny little wars between them, and were finally unified by the House of Savoy, ruling over a principality which is now in France. When the Italians tried to build an empire they got beaten by Ethiopia and Greece. The Romans were known as dour pragmatists, who looked down upon the artsy Greeks. The Italians are heavily inclinded towards art and entertainment, and are not exactly known for their pragmatic approach to life.
The geography of Egypt has not changed all that much since the days of Eratosthenes and Ptolemy the Astronomer. Nevertheless, nowadays Alexandria is not really among the focal points of world culture.
The geography of Japan has not changed one little bit since the days of Tokugawa Ieyasu. There is little similarity between the self-isolated country which stubbornly refused to engage with the outside world and the modern industrial hyperpower.
The geography of modern Germany is the same as the geography of the same territory during the Middle Ages. While for a thousand years the Germanies were divided into a bewildering patchwork of states and statelets, suddenly in the second half of the 19th century Germany emerged as a unified superpower with ambitions to take over the world, first through force of arms and now through engineering and technology.

Geography is important. It cannot be ignored, and it cannot be circumvented. But miracles do occasionally happen. Alexander the Macedonian king transformed Greece into a superpower, albeit for a short time, but that short time was enough to change the culture of all the peoples from the shores of the Mediterranean to India. A tribe of Turkic-speaking nomads from central Asia took over the (Eastern) Roman Empire and ruled for half a millennium. A small, cold and rainy island took over large, rich and populous India, gave it a common tongue and made it into a united country.
History is not predetermined.

Excursus: the foundation of Byzantium.
The question states that "geography is paramount to where we have settled and why we have settled there". Here is a classical semi-mythological anecdote, which was transmitted to us by Strabo the Geographer.
In the 7th century before the common era, Megara, a city located on the Greek isthmus, was in full colonizing mode. One of the their colonizing efforts was led by prince Byzas, officially the son of king Nisos, and mythically the son of Poseidon, the god of the seas. Prince Byzas went to the oracle at Delphi to ask where to set the new colony. The oracle replied that he should establish a new city on the land "opposite the city of the blind".
Byzas went in search of the city of the blind, but nobody had ever heard of such a city. As he sailed north through the Sea of Marmara and entered the Bosporus, he noticed on the western bank the Golden Horn, which provided a magnificent natural harbor. Opposite the Golden Horn, on the eastern bank of the strait, was the small city of Chalcedon, an older Megarian colony.
Byzas immediately realized that Chalcedon was the city of the blind, as only blindness could have made anybody establish a city on the wrong bank of the strait. He established a new colony on the western bank of the Bosporus and called it Byzantium. In time, the city he founded was to be renamed Constantinople, and would get to be capital of two great empires; today it is called İstanbul and is the most populous city of Turkey. As for Chalcedon, it is now a district of İstanbul.
Comment: I love this answer.  Frankly, a city by the ocean is more likely to eat fish than a city next to an oasis in a desert.  But when the civilization grows large enough to encompass both cities (with a little tech), the coastal city starts eating dates and the desert city starts eating fish.  And neither location is likely to invent drums than the other. Geography has an impact, but it's not the central cause of most culture (or even a predominant cause, IMO).
Comment: tl;dr = geography, time, and charismatic leaders all factor into the culture of a nation, it's highly path dependent.
Comment: @NamNguyenHoang Mongolia as a whole sure, parts of mongolia are plenty productive. much like egypt mongolia does have productive regions and they are all centered around rivers. Not that it matters how long did the mongolian empire last, a generation. It fell into the trap I mentioned, it exceeded its communication capability and  couldn't hold itself together.
Comment: @John: The Mongolian empire survived for a generation or so *as an integrated whole*. But the large pieces into which it broke survived for quite some time. The [Golden Horde](https://en.wikipedia.org/wiki/Golden_Horde) for example.
Comment: What an excellent answer!  Thank you!
Comment: "History is not predetermined." ... assuming free will  actually exists. Cosmology has this as an open question. :-) But I agree that the *distribution* of historical events is non-uniformly distributed.
Comment: @SRM: The linkage between the presence or absence of free will and historical determinism is tenuous at best. It is perfectly possible for humans to lack free will and still have a stochastic future. In fact, we are quite sure that tritium atoms do not have free will, and yet the lifespan of any given tritium atom is not predetermined.
Comment: Note those large societies only arise in a very specific kind of terrain however.  Most of the changes you talk about happen well after to have advancements in technology that makes geography less important. This answer is less about geography than how technology changes society.
Comment: @John: The Roman empire arose from a city state in a narrow, mountainous peninsula. The Persian empire arose from a culture of nomad horsemen. The Chinese empire arose from a culture of settled farmers. All three went on to become great empires. Geography is an important and inescapable component of human development, but it is not in itself a determing factor. Consider that, for example, both the Greeks and the Phoenicians were great navigators and colonizers; yet (1) Greece and Phoenicia are very different geographically and (2) no other Mediterranean culture chose that path.
Comment: All three arise in river valleys, places with high productivity, places where large food surpluses were possible.
Comment: @John: Calling the Tiber a valley with high productivity where large food surpluses were possible is quite a stretch, isn't it? The entire Latium (which Rome shared with several other cities, some of them not even Latin) is about 350 square miles (900 square kilometers). And you may be confusing the Persians with the Babylonians; the Persians are not native to Mesopotamia -- their heartland was in [Fars](https://en.wikipedia.org/wiki/Fars_Province), which is on the [Iranian Plateau](https://en.wikipedia.org/wiki/Iranian_Plateau).
Comment: @AlexP Not really, the tiber is 400 km long and the soil was very fertile thanks to the local volcanics. As for the persians there are numerous river valleys within the fars. the plateau. is not really a plateau  I think you are confused about what I am saying, I am not saying productively perfectly predicts which one of a thousand cilies will rise to power. I am saying you have to have high productivity before the question even arises. there is a reason we don't see large societies spring from open desert, tundra, or small volcanic islands.
Comment: @John Genghis Khan disagrees. Even today, Mongolia is still not considered the most productive of places.
Comment: @John, and you too, AlexP, I think we are getting somewhere here. Assume each nation is like a car, then the geography, resources, etc. is its starting fuel (even worse place on Earth still count as something as it is at least human-habitable), and the people, institutions, governments are its engine, good ones make a drop worth a mile, bad ones destroy the whole thing.
Comment: @NamNguyenHoang thats not a bad analogy, no matter how good the engine your not going anywhere on an empty tank.
Comment: @AlexP and look at where those pieces, where dos it persist, highly fertile land, you can even see the territories think back towards fertile land as time goes on.
Answer: Geography has some influence on the culture of the people living in a certain region, though it is not the only force shaping it.
Look at the USA. Without the vast spaces opening to the west, the Anglo-german colonists of the 13 colonies would have hardly changed their home culture into the one of the self made man. You can also see how the sports which are popular in USA (baseball, american football) are a metaphor of the slow gain of territory, while the european favored sports are more resembling a codified war.
Or look at UK and Japan: without their insular geography, could have they thrived in their isolationist culture? It's a famous joke the headline of the English newspaper "thick fog on the Channel, the continent is isolated!".
Answer: 1) Our species evolved on the savanna and by standards of the animal kingdom, we're master long distance runners. Our brains have neurons connected much more than in other animal ones, give edge not only for abstract thinking but also for hunting animals by running them in to total exhaustion. Not sure whether you can change that for purpose of your story.
2) Our civilisation flourishes in interglacial period. Right now we're roughly in cycles ~120k years of ice age, ~20k of interglacial period. (Rough approximation, see Milankovitch cycles). You may subvert that by having in your timeline to almost make civilisation in intergalciar period, fail it, and actually achieving hardly worked success in another ice age, just for practical purposes whole geography would be different. Extra bonus - because of wobbling of Earth axis, there are periods in which Sahara is more or less green
3) Our brains are still evolving. Especially at extremes environments - apparently cold winters are good for your brain, as such predictable cycles tend to eliminate the least fore planning members of one's tribe. Without this point is hard to explain that there are some differences in average brain size between ethnic groups matching this pattern. In our history it did not matter much, but there was another similarly suitable environment - it seems that Polynesians evolved too some edge in spacial intelligence and ability to keep direction.
There is also additional suspected factor - seems that some civilisation tend to self reinforce themselves, by introducing harsh rule of law. From evolutionary perspective it means executing (thus eliminating from gene pool) the low IQ and high sociopath individuals. On the other hand is genetically undesirable if intellectual elites keep number of kids low (contraception, celibacy, etc.).
4) If you want to domesticate big animals, then better co-evolve with them. Even Jared Diamond points out that in Americas there had been horses and camels, just they were hunted in to extinction. Unless it's just a fluke, it seems that animals in Eurasia had a chance to co-evolve with us, so survived a bit longer to give us chance to domesticate. TLDR: it seems that there were more species to domesticate.
5) Civilisations tend to start in hot river valleys and spread to colder regions but they are to be trampled by nomads. Even if civilisation look impressive, the even more impressive thing is a group of warrior nomads, that are highly mobile. Ask neolithic Europeans and India peoples about Yamnaya, ask Romans about barbarians, ask whole Eurasia concerning Mongols.
6) Yes, premodern civilisations tend to produce superbugs. Regardless whether it's indeed issue of domestication of animals, or just a problem of close proximity and big groups of humans - it happens. So whatever there is, first your cities would be suffering from plagues (medieval European cities needed steady influx of people from villages, just not to get depopulated). Later, when you came in to contact with primitive, isolated tribes... let's say that your weapons are not their greatest problem.
7) It's a bit tricky to get different humanoid species. is a general rule - in long run two species can not occupy the same niche - whoever is even slightly less adapted, would be outcompeted. Ask Neanthertals or Denisovans. If you want to keep it realistic - some of your species should have a different and clear edge that works really well in some environments, but is detrimental in others. To be fair, some fantasy books (the original Witcher Saga) got around this problem neatly, as after some kind of magic cataclysm species from different worlds suddenly met, and is implied that humans are effectively highly effective invasive specie that already mostly exterminated elves.
Answer: There are a few powerful factors.
Productivity: You are not going to have large sessile communities on unproductive ground, large cities require fertile ground and plenty of water just to keep themselves fed and watered. So what we call "civilization" (large populations, specialized labor, advanced technology) always start in places with high fertility and a good water supply, most of the time that means a river valley or large lake. Timber is also important for such societies, more than once advancing societies consumed all their local forests and fell apart, no wood means no fuel for cooking and almost no building material. Note however river valleys are not rare.
Wildlife: what plants and animals are available has a strong impact, animals that can do work and domesticated plants that have a long shelf life (grains) makes for very powerful civilizations, it means large food surpluses and ease of travel for trade (or war) One of the big limiting factors the Inca experienced was war could not be sustained for long because they needed the labor for agriculture. This limited how far they could expand. You as the world creator have a lot of control over this one however.
Ease of travel: The easier it is to travel the larger an society or empire can be, large states need to be able to communicate rapidly to persist, Often this is water based, rivers or seas, but flat plains also lend themselves to it. If communication takes to long you don't know what is happening on the borders soon enough to do anything about it and you start loosing land to rebellion and conquest. Egypt could be one large state because everything was within a few miles of an easily navigated river. Don't expect states to expand across harsh mountains or desert unless they have a coastline to follow around it.
Islands: you would think islands would be good for societies but small and volcanic islands in particular run into a problem, lack of resources. I mentioned wood, but they also lack metals, water sources, and variety in organisms so island cultures tend to be doomed to limited technological development. Islands have to be very large (japan) or very close to the mainland (and thus on continental crust) before they overcome this problem.
In short big communities and thus later big states always occur in river valleys if it is near the ocean even better, you shouldn't have large states is poor environments or springing from seemingly nowhere. The size of a community effects a lot of other things, but most come down to is there enough food surplus for specialized labor, and will the society exist long enough to exploit it. If you want a society to have technology, classical governments, social classes, or even just cities, they have to be in a place that can support them. One of the giveaways of a fantasy setting is a huge empire that somehow persists in wasteland.
There are a lot of smaller factors too, many cultural differences (but certainly not all) originate in differences in environment or in unshared or unique solutions to said environment. But such a list would be well beyond the scope of a single question. At the same time a lot of cultural factors are completely unaffected by geography, geography provides more of a rough constraint than detailed prediction.
Answer: Culture is deeply connected to food. Just look at any culture you can think of and they all have dishes they identify as their food, owning it either by ingredients or the way ingredients are treated. Believes and traditions grow on to what first began as simple environmental conditions, providing certain food, disallowing for others.
Geography forms different environments that allow for different plants and animals to dwell. Imagine a very dry, warm land, and how hard it will be to grow crops if water is sparse. People settling in such areas will mostly rely on livestock that is able to eat tough desert plants, and won't consume a lot of water. That is actually considered the origin reason why muslim countries don't eat pork: the meat of pigs does not last as long as goat meat, and pigs use more water. Here you can read a good summary. So the conditions that geography provides are very much responsible for the cultures that develop out of it.
Compare variety rich regions, which provide water, forests, plains and mountains in mild weathers full of wild life and the people will be healthy and happy to share what they have, to regions with unpredictable cold and windy weathers and only fish as their main source of food, and you will get folks with a harsher view on life.
You are what you eat. Nowadays we are able to eat almost ALL the dishes humanity has come up with, but just a few hundret years ago (or even just a half century ago) that was only possible for very few people. Kings in the past did not nearly get the variety of food we get today. In times of hunger many farmers and their households would eat porridge. Only porridge. For breakfast, lunch and dinner, every day of the year. Keep that on for some generations and the culture which grows out of that, even when eventually some bacon gets on the table, will call their children to be grateful for what they have and demand to be considerate. The demands of circumstances will become traditions will become religion.
Answer: Geography in a society determines more than you think, in fact everything
Jared Diamond, professor of Geography and Anthropology at the University of California, is a strong advocate of Culture linked to Geography, as outlined in his books Guns Germs and Steel, and Collapse.
Fundamentally, he asked himself the question Why did the Spanish invade the Aztecs instead of the other way around?
The answer, he concluded, was all simply geography. He made a few points:

There is little to no difference between races physiologically. We have the same brain masses, essential genetic makeup and the same physical abilities. Therefore the reason cultures are different is due to only environmental factors.
Continent size and accessibility is a key factor in development. Europe and Asia had a wide, latitudinal aspect ratio, meaning climate was constant and physical geographical features were not impassible. This lead to the interaction of different peoples on the continent, pushing development, conflict and cooperation. In contrast, South America had varied conditions as it was a longitudinal continent, with impassable jungles and mountains, making interaction between cultures almost non-existent.
Geographical features influenced strongly food, crops and farms. In Europe, large areas of fertile soil combined with a crop (wheat) of high yield allowed cities to grow fast, and food to be easily cultivated. In contrast, South America had no such high yield crop, so number and size of cities were numbered. Also, mountainous terrain and jungle impeded transport, such that cities were limited to walkable distance from water holes, as opposed to Europe where towns were large, spread apart and wheeled transport allowed trade of goods.
Geography also influenced animal husbandry - Europe having wide geography with links to Asia and Africa, had species easily domesticatable and scalable. South America lacked any such animals. Australia also - kangaroos do not make containable stock being fast and agile, so Aborigines were unable to breed and cultivate them. Cows, horses, chickens and sheep however are easily contained and bred, and allowed large cities, trade and mastery of transport and breeding.

In the end, culture is determined essentially by interaction. Jared Diamond offered the explanation that evidence suggests reduced interaction limits cultural development, whereas increased interaction, although conflict-ridden, pushes it forward and develops it in new directions.
Comment: 1) I think you may missed the "germs" part, which was the only place where JD was accepting notion that we may still be evolving. 2) Wheat... yes, that's one of the weakest point of the whole theory, as potato bring higher yields and revolutionised Europe https://go.galegroup.com/ps/i.do?p=AONE&sw=w&u=googlescholar&v=2.1=r&id=GALE%7CA54668867&sid=googleScholar&asid=fd6a86d3 3) In which exactly study they ended up "essentially similar"? In the linked article they were wondering how to explain 21 IQ points difference, which awkwardly correlated with differences in brain size...
Comment: Well, this point concerning brain mass is not exactly correct... "African-descended people (Blacks) average cranial capacities of 1267 cm3, European-descended people (Whites) 1347 cm3, and East Asian-descended people (East Asians) 1364 cm3." https://www.sciencedirect.com/science/article/abs/pii/S016028960200137X
Comment: @Shadow1024 Yes point taken, I think the implication was that they are essentially similar.
Comment: @Shadow1024: The Neanderthals had an average cranial capacity of 1,600 cm³. "Africans" is not a natural grouping -- some Africans are Europoids, and the rest show much more diversity than the rest of mankind combined. Males tend to have bigger heads than women. What is your point?
Comment: The question "why did the Spanish invade the Aztecs instead of the other way around" is silly, and it is one of the weakest points of Diamond's book. The Aztecs were a stone-age civilization. The Spanish had an advantage of four millennia of technological development. With such a huge difference all other points are insignificant. I am of the opinion that he chose this example because it fit his program; other examples would be must less fitting -- why did the Romans conquer Gaul and not the other way around?
Comment: @AlexP Yes, they did. It fits neatly cold winter hypothesis. Nevertheless, it seems that Homo Sapiens had some qualitative edge here, as after hybridisation,  Neanderthal neurological genes were selected against.  // Based on genetic cluster studies it is, even if computer is supposed to group humans in to two genetic clusters you end up with Black Africa & the rest. So I'd say that this distinction is a natural as possible. en.wikipedia.org/wiki/Human_genetic_clustering // Yes, and it gives males an edge in spacial geometry tasks. // Point? We're not biologically identical and it may matter.
Answer: You need to keep digging for stuff.  Lots of good examples here.  Here's a few more:

Mediterranean soils tend to be loose and sandy.  Tillage was in effect done with a sharp stick, dragged back and forth in a cross hatch pattern by oxen.
Northern soils were heavy clay, and farming was essentially impossible until the creation of the mouldboard plough.  The horse collar, and the breeding of heavy draft horses helped.  Fields were long and narrow, because turning a plough is hard, and so that the eventual crown to the field (soil is always turned toward the centre) created drainage ditches, which allowed the fields to be sowable earlier in spring.
Climate has a huge influence on architecture.  Cloisters -- essentially large covered porches give living areas protected from rain, but fairly well lit.  Windows before glazing are cold. Scots peasants had 'black houses'  No windows at all.  Just the light from the open door or the sullen glow of a peat fire.  Monks in scriptoriums in northern climates complained about their ink freezing.  There are reasons why 12 century portraits show so much clothing.  Houses were built with living quarters above stables.  A cow is a 2500 BTU/hour thermal machine.  You don't let that much heat go to waste.  You see this even today.  Houses in southern areas have large windows.  Sometimes the boundary between inside and outside is blurred, with outdoor kitchens, patios...  Housing in northern climates tends to smaller windows, tight fitting seals on doors, storm entrances.
climate has a huge influence on clothing.  Imagine a roman toga in Lapland during mosquito season.  Those multiple layers of thin white fabric of the desert peoples are actually cooler than skin.  In a humid tropical climate, skin works better.  This in turn had effects on what was considered moral behaviour.
Cities tend to grow where products have to change direction, or mode of transport. On land look at where major routes cross.  On rivers, look at the mouth, and major confluences.  Obstacles, such as falls, or mountain passes also create cities.  The pass may only be open part of the year.  The falls requires portaging all your gear and goods, and perhaps the boats.  See history of the Silk Road for more examples, as well as where cities sprang up on the Mississippi/Missouri/Ohio river systems.

An example of the latter:  The Canadian fur trade uses Canots du Maitre to haul from Montreal to Grand Portage.  This was a 36 foot canoe.  Voyageurs carried goods over the Grand, (9 miles) but they used a smaller Canot du Nord, about 23-25 feet long with about half the cargo, but only one less paddler.  They didn't portage canoes over that portage.
Later on, furs came south on the McKenzie, and Slave rivers then up the Athabasca to Athabasca Landing, transhipped by cart to Edmonton, then down the Saskatchewan, and down the Hayes to Hudson Bay.  The round trip for trade goods for furs took 6 years for the extreme ends of the trading empire.

In island archipelagos, people on opposite sides of a straight often have more in common including language than people on opposite sides of the same island.  It's easier to move by boat.  See south west pacific (China sea, Coral Sea, Indonesia...) for examples.
In the Canadian Arctic it's reasonable to travel thousands of miles along the coast by dog team. (Distances of 100 to 150 miles a day on smooth ice are reasonable.)  Traveling inland is much more difficult.  Languages reflect this with each area's language being mutually comprehensible for about a thousand miles either way from Point Barrow to Greenland.  However coastal Inuit and Caribou Inuit had different languages -- and different technologies. Coastal groups are based on hunting seal, both on the ice, and by kayak on water.  Inland groups are based on caribou. Further inland you get Indians (I'm at a loss here for the proper term to distinguish Innuit from other first peoples...) with the boundary being roughly treeline, and a much greater dependence on wood as a material for making dwellings and tools.
Variable climate requires civilization of some sort.  Variable climate means one year's food production isn't guaranteed.  Food storage becomes a critical factor in the stability of cities.  There was a lot of grief in the Mediterranean about 1150 BC with a climate shift that dropped crop yields.  See also the old testament stories of Joseph, and fat/lean years.  This applies to nations too.  India used to be unable to feed itself in my memory.  The green revolution of fertilizer is one reason this has changed, but a bigger reason was rat proof grain storage.
In addition to Diamond's books, already mentioned, look at James Burke's book, "Connections"  It details a bunch of interacting bits of technology, history, climate, coincidences, and show how some changes are pretty arbitrary, but others are inevitable.
Answer: The short answer is the higher the level of technology, the less that culture depends on geography. But the initial trajectory of a culture is shaped by geography.
Primitive and early humans were completely at the mercy of their environment. If you live next to a river, then you have a chance of setting up agriculture. If not, then you're stuck with hunting-gathering. If you live next to a cliff with natural caves, then you have a convenient place for shelter. If you live in the rainforest, then you're going to have to improvise a shelter on your own. Cliff-dwellers don't need to learn how to build houses. All of this will affect how people live together and form a society, what they eat, who they worship and how. In other words, their culture.
However, as technology advances, "geography" shrinks. Nowadays we can drive over 100 miles to see an event; traveling such a distance would take many days and be very hazardous for a medieval peasant. We can chat with a person in India in real-time through our computer. We can eat fresh fish in the middle of the Arabian desert. We can order clothing made from silk in China and have it shipped to Nigeria. We can fly to Paris to see the Eiffel Tower in person. Technology has eliminated many of the constraints once forced upon us by distance.
There are still some practical limitations. We can move out of town if we don't like living here, but it is a hassle. We might drive to a more distant restaurant that we would not consider walking to, but a three-hour drive is probably out of the question. We tend to form friendships with people that we meet in person i.e. within close proximity. In the future, even these constraints will probably vanish. Then we can effectively be wherever we want, eat whatever we like, and hang out with crowds we like, however distant. Geography will play little role in the picture.
But beginnings are often the most influential stage of life. All societies begin at the primitive level and slowly develop technology, of course. Which means that their initial culture was, in fact, profoundly shaped by their starting geography. This would have an impact on what kinds of technology they develop, which would in turn change how the geography affects them, and so on. Thus, all cultures emerged from, and developed in certain ways in response to, local geography. This leaves a lasting mark on the traditions of that culture. However, once cultures become advanced enough and start interacting with each other, the direct impact of geography declines. What remains are the lingering effects of the initial traditions shaped by their "original" geography.
Answer: try and think about which factors of the land are constant, and then let your imagination run from there. what sort of culture can you imagine sprouting from each area? it shouldn't hold you back, just offer some seedlings or cores for your 'traditional' cultural identities.
before things get modern, you'll notice that culture is closely tied to the land. remember that most people are born and die in their own bubble, which may consist of rice paddy farming all day, or working in massive metropoli, or spending their days on the sea, and to this day you can find these remote bubbles of culture and it'll all to various degrees take on the outer appearances of the broader cultures around them, but the details will all be closely tied to the land and natures cycles and what they have to work with. try and consider all of japans region-specific festival topics, and compare it to them eating kfc on christmas
perhaps its more important to consider how fluid the culture of each place is, and then have geography win over the broader cultures, that you're free to paint onto your maps, in rural or distant or closed-off places. that way is more natural
Comment: Welcome to Worldbuilding.SE Crosshill, glad you found us.  We have a [tour] and [help] you might wish to check out.


How do I batch import multiple images as individual layers in Krita?

Question: I have already tried importing multiple images with File -> Import Animation Frames. I tried importing a single GIF image and it didn't extract the layers so I did it manually myself, then I went back and tried to import each extracted png frames and it still only imports 1 single frame. What am I doing wrong? Does Krita not have this basic feature?
Answer: To import multiple images as individual layers in Krita (4.0) you can use Layer > Import/Export > Import layer and then in the file chooser dialog box, select multiple images and then press import.
For importing sequential frame use the Import Animation Frames, Also use the animation work-space to check your animation layers in Timeline.


TYPO3 Extension Manager doesn't work

Question: I've uploaded TYPO3 CMS version 6.0 on my web server and successfully installed it. The problem is when i try to access Extension Manager, it gives me following error
<code>Could not determine the child object type
</code>
Answer: Try to remove TYPO3 cache files from typo3temp folder then reload BE and try again.
I had the same problem and this helped me.

TYPO3 Extension Manager doesn't work


LEGO WeDo and Mac OS X Lion

Question: Just got a new Mac with Mac OS X 10.7 Lion instead of burned old one. Now I can't install WeDo software since its installer doesn't support Lion. Google search suggests that LEGO released a patch to installer that solves this problem, but all links are broken. Any help in adapting WeDo software to Lion is appreciated.
Answer: I believe this is the current location for the Lion Patch
In the interests of finding it again when the LEGO group change their site again:

Visit the LEGO Education page.
Navigate to "Pre-school and School" -> Secondary -> 11+ LEGO MINDSTORMS Education -> Downloads (or similar)

I then filtered the list to just the Download Type of "Software Update / Patch".
Answer: The solution just lain on the surface! To install WeDo you should open Support folder in DMG image and DIRECTLY click on English or yourlanguage.mpkg to launch installation program.

LEGO WeDo and Mac OS X Lion


The word "Comparison"

Question: Declare - declaration. Proclaim - proclamation. Why isn't compare - comparation? For the 3 years that i've been studying the language intensively i've been always intuitively reading "comparison" as "comparsion", thus pronouncing it like "compartion" (sort of short of "proper" "comparation"). Today i found out that it is actually "comparison". That's the weirdest thing that's happened to me since i started learning English. Why is it such a weird word? It sounds so French. Can you give any other examples of similar noun formation?
From the web: "Definition of "ison" [ison] A suffix, really -son, with an element (-i-) belonging to the stem in some nouns coming from Latin through the Old French. It is equivalent to -ation, -etion, -ition, in nouns originally abstract. Examples are comparison, fermison, garrison, jettison, orison, venison, warnison."
But i don't really know any of these words, they all seem to be loanwords, while "comparison" is ("from Old French comparesoun, from Latin comparatio(n- ), from comparare 'to pair, match'") initially originated from Latin. So "comparation" or "compartion" would be a word more suitable for the English, would it be not?
Just a discussion, not trying to prove anything. Would appreciate if someone points out any mistakes i have in the question body :)
Answer: I think you've answered your own question. The etymology of comparison travels through Old French. The -tion words you mentioned have not.

The word "Comparison"


Set Default landing page

Question: I created my own custom app, now I need to set this app as the default landing app. In Salesforce Classic I went to Profile -> App -> Custom App but when I logged in after I switched in lightning, I ended up in the Setup Tab. Why? How I can set the custom app as the default app also in lightning?
Comment: Did you try with another profile other than sys admin?
Answer: with the help from my colleagues I found a solution. In lightning in the user interface you must un-check a chekbox that says:

set Setup my default landing page.

If this check is true you always end up in setup despite the default app you set.
Answer: In lightning you would have to go to: Setup> Apps> App Manager, and then create a Lightning app. In the wizard you'll see you can configure mostly everything, including which profiles will have access to it.
I hope it is useful!
Answer: Default app configuration comes from Profile. But if a profile have access to multiple App Salesforce remembers which one the last app being used by the user.
For example "Sales" is the default app for Sysadmin profile and it has also access to custom app "APP ONE" now if you are in sales app in classic view whenever you login in classic you will see sales app landing page after login.
Now you switched to lightning and gone to "App ONE" and log out when you log back in you will go to "App One" landing page.
Now you switched to classic you will go to Sales landing page - Salesforce remembered your choice.
Now you switch your view to lightning you will go to "App One" home page
So the landing page will be same if you have access to only one app in classic and lightning.
Salesforce remembers in which APP you left your classic app as well as your Lightning app.
Hope this answers your question.

Set Default landing page


Migrated mbox to Maildir, how to avoid mail client from re-downloading emails?

Question: We have moved emails in a postfix server from huge mbox files to MailDir, but when trying out one Outlook client, found that it redownloads all mail as duplicate unread messages.
Answer: This is not really a postfix problem.  Instead the issue probably is the way you converted your email from mbox to maildir.  If you do not preserve the message UIDs when converting from mbox to maildir, the client can't tell that the messages are the same, and will therefore re-download them.
It would be helpful to know which IMAP/POP software you are using.
You might find the information on this dovecot page useful even if you are not using Dovecot as your imap server.


Is 'temping' a culture-specific term?

Question: I have a character working in a short-term temporary position in an organisation and refer to her doing the work using the usual UK word, 'temping'. Will this be understood by readers in the US and other English-speaking cultures? If not, is there an equivalent culture-neutral term or should I spell it out?
Comment: As others have pointed out, the term "temping" is common in the US (even as a verb).  Since the question is now on the home page (I fixed the tags), maybe we can get some answers that talk about the term's usage in English-speaking countries other than the US and the UK.
Comment: In Denmark we use a similar term, "vikar", an example of which could be a (temporary) substitute teacher. Can the "temping" refer to someone undergoing an internship? We also have the 'intern' term (praktikant) for paid and unpaid work. My point is: I'm not a native English speaker, but I believe "the avergage English-speaking Danish person" would understand your use of it. This could of course be based on or influenced by pop-culture, but I would hope that native English-speaking cultures would understand it too.
Answer: I believe the word "temping" is culturally-specific, but not along national lines of culture.  An American with experience in corporate environments where temps are common would know the word.  A Brit without that corporate experience might not.
In either case, the word is pretty self-explanatory.  I would use it without hesitation in anything I wrote.
Comment: As someone from the US without any corporate experience, I pretty much knew exactly what it meant without any context (just seeing the title).
Answer: All slang is culturally specific. The meaning of most of it can be figured out by context though. Certainly "temping" falls into that category.
But vocabulary recognition simply does not happen on a word by word basis. It happens in the context of the story being told. As kids, we pick up new words all the time, not from having them defined for us, but from hearing them used in context and seeing what they mean and how they are used. (This is why learning to speak a second language idiomatically from a book or in a classroom is so difficult. We don't get to see use in context.)
You can make up entirely new slang and just use it in context and if you set the context right, the reader will pick up its meaning.
Answer: Why not be safe? Explain the term the first time you use it. E.g.

Joan was working in a temporary position. She hated temping.

Something like this doesn't feel strange to those that know the word, and it helps those who don't.

The question, always, is who you write for. If you want to reach the widest possible audience, avoid jargon and slang, or explain it.
And, please, don't think that because a handful of other writers here on this site know or understand that word, the common reader will, too. If you want a useful answer to your question, you need to sample your target audience.
Comment: I only know what temping is because I watched a lot of Doctor Who. Had absolutely no idea what it meant the first few times they said it on the show, but I was also, like, twelve
Answer: We have Temp Agencies in America, that, as their name implies, find temporary work for people. The people who work in temporary positions are referred to as "temps." I first heard the word in ordinary conversation when a friend referred to an acquaintance as a temp. So I recognized the verb "temping" immediately.
However, I'd never heard "temp" used as a verb, so out of curiosity, I did a google search to see if "temping" as a verb occurs in American English. Yes, it does. Here's an American article that came up:
http://www.bestessaywriters.com/essay/the-temptations-of-temping/
I also found "temping" in this online American dictionary: http://www.macmillandictionary.com/us/dictionary/american/temp_2
(Underneath the definition, the user can click on "See the British English Definition", which in this case was the same as the American definition.)
So, I'd say you're safe to use it for your American readers. Perhaps you can do a country-specific search to determine if it exists in other English-speaking countries.

Is 'temping' a culture-specific term?