How long will flour keep in the freezer in Food Saver Vacuum Sealed Bags?

Question: I found some flour in my freezer that I stored 5 years ago in Food Saver vacuum sealed bags.  Do you think it's still safe to use?
Answer: I'm reasonably sure that flour stored this way is safe.  Obviously, if there are any obvious issues with the flour - off colors, tastes, or textures, or evidence of poor storage that allowed the flour to thaw and refreeze, or leaked moisture into it enough for quality concerns - you would want to be safe and discard it, but it should be reasonable to expect the flour to still be safe if it was properly stored.
Flour has a shelf life of 5-10 years if well stored.  On top of that, freezing usually doubles the shelf life of grains - and that doubled time is best-before time, the flour may still reasonably expected to be safe after that amount of time, just with reduced quality or nutrition.  Storing foods in the freezer, if kept consistently at temperature and well wrapped against moisture, is often about loss of quality rather than safety in any case.
So if the storage was uncompromised, flour stored in the freezer should be best used before 10-20 years.  As for how long after that your flour may be edible for, well, hardtack has been known to last fifty or a hundred years, and still work for rations without killing or starving the eaters - I would guess probably modern freezers intended for food preservation are at least as efficient as baking the flour into dry dehydrated cakes (which is really all that hardtack is).  That may explain why flour is said to last indefinitely if properly stored in a freezer.


How do I transfer files fast over two network shares?

Question: I have two shares (A, B) on the same volume on a synology NAS. I'm have the two shares mounted in finder, but when copying or moving files it takes forever, even with SMB3 on. I can of course use Synology's file browser which takes seconds, but the issue is that I can't easly open and preview files - I would like to use Finder if possible or at least an app for Mac that would allow me to open the files.
Comment: So you are copying a file from NAS Share "A" to NAS share "B" and you are wondering why it is slower than moving a file logged into the NAS user interface? It's because you are transferring the file from "A" to "B" VIA the Mac. The Mac is doing the copy operation so it goes from "A" to the Mac and then to "B" effectively two slow *NETWORK* copy operations. It will **always** be slow that way.
Comment: You had two questions in here. This site works better when there is only one question per question. That way, it's easier for other people to find solutions if they have the same problem. I've edited out your second question, but feel free to ask it separately.
Comment: Instead of using Finder for the transfer, use the Terminal commands `cp` or `mv`. Using Finder adds lots of overhead to the transfers, whilst `cp` and `mv` are fast, and can handle transferring folder structures and other cool stuff.  You might also want to consider using `rsync`, which is [discussed here at AskDifferent](https://apple.stackexchange.com/questions/117465/fastest-and-safest-way-to-copy-massive-data-from-one-external-drive-to-another).
Answer: Moving files from one share on a host to another share on the same host will always be faster when initiated from the host itself, and will always be slow when transferred from the host to a client (and back).  Regardless of whether you use Finder, or mv or cp or Carbon Copy Cloner, if the data has to traverse the network, it will be orders of magnitude slower.
There are some technologies that allow a copy or duplicate command on the same share to be initiated by a client and performed server-side instead of copying the whole file down to the client and then back.  I believe SMB supports this, but it it won't work across different shares, even if they're on the same host.
Long story short, your network will always be the bottleneck compared to the disk controller's native speed (~88MBps for Gigabit Ethernet vs. 200-600MBps for SATA). If you're running 100Base-T on your network instead of Gigabit, you'll be 10x slower than that (8MBps).
To (pre)view anything on the Mac, you'll always have to transfer it (or enough of it) to the Mac over the network.  For large items, I'd recommend using the Synology's interface to move or copy items between the different shares.
Answer: From my experience, Carbon Copy Cloner as a rsync gui makes better use of the bandwidth available compared to copying using the Finder's drag and drop. If you don't want to use the NAS interface, that's the only way to maximize the transfer rate.
I will also suggest using Menumeters to measure your network speeds, and use a wired Ethernet connection instead of Wifi if this is applicable.
Comment: The value of AD (and other SE sites) comes from answers which go beyond mere product recommendations. It's fine to recommend tools, but wouldn't it be even more helpful if an answer also explains (to the OP and any future visitor) how a tool you use and know can be used in the context of the question?
Comment: @historystamp It's fine to propose different policies, please raise a question on the meta site for this.
Answer: I'm not exactly sure if this is what you need but you may be able to use either the 'scp' command for remote transfers or the 'cp' command for local transfers.
cp /Volume/share/path1/* /Volume/share/path2

Use * to copy the entire contents of the folder.


Missed connecting flight

Question: I fell asleep at the gate while waiting for a connection flight to the UK from South Africa. I was connecting on Kenya Airways. They say I have to pay charges which are more than buying another air ticket, but I don't have money. They say they can't help me unless I pay. My luggage is gone. What must I do?
Comment: Are you traveling to a foreign country or your home? If the first, you probably will have to simply cancel your trip if you cannot pay. However to get home. Many governments offer some kind of emergency assistance for citizens stranded abroad, but I do not know your citizenship so cannot advise on that.
Comment: Most embassies will NOT pay your way home if you are stranded abroad without funds. The best you are going to get is some assistance in getting someone else to wire you funds.
Comment: You could try to talk them into letting you fly standby on the next available flight, but I suspect your chances are not so good.
Comment: If buying another air ticket (right now, the price varies depending on when you buy), possibly on another airline, is cheaper, why not do that instead of paying them the relevant change fee? That is, of course, assuming you can afford the cost of another ticket instead.
Answer: Unfortunately there is really nothing you can do since they fulfilled their part of the contract. Your best bet is getting a sympathetic manager or supervisor to waive those charges. Unfortunately Kenya Air to the best of my knowledge do not have a robust customer service/rewards club number you could call for consideration. Barring that you have to hit up friends and family to wire you some money or wire to Kenyan Airways so you can continue your trip.
Concerning your luggage, they have to return it to you IF you choose not to continue your trip. Normally the luggage would even be taken out of the hold when some passengers doesn't continue  onward. Now if you are a US citizen and have a visa to enter Kenya, you could go to the US embassy and request Emergency Financial Assistance however my understanding is it is only granted in the most desperate of cases.

Question : What other assistance is available to a destitute U.S. citizen if family or friends cannot provide financial help?**
Answer. Destitute U.S. citizens in need of help overseas should contact the nearest U.S. embassy or consulate or the U.S. Department
  of State, Office of Overseas Citizens Services, at (888) 407-4747 (or
  from overseas +1 202-501-4444), for information about other assistance
  options and eligibility requirements

Your country of citizenship might have something similar to the USA.
Answer:
Check your fare rules. These have been provided to you when you bought the ticket. Unfortunately they tend to be very hard to read, but they do spell out what cancellation and change fees do apply and what the rules for re-booking are.
If this is the first part of a round trip, go to the airlines and make sure that they don't cancel your return trip. They may have cancelled it already, but it can be re-instantiated
As the others pointed out, you have very few rights here but the airline has a fair amount of discretion to be nice or nasty to you. Your best shot is to talk to different a few different gate agents and see if you find a sympathetic one. Be respectful and polite. Be friendly and co-operative. Be apologetic, this is after all your mistake.
Try to be creative: "if this flight is full, how about one tomorrow?" "i'm happy to take a routing with 3 stops, if that's easier for you" "what do you think is the best way to unite me and my luggage?"

Most airlines will handle this decently: put you on another flight and maybe charge you a change fee (ca. US $300 or so).
Answer: If you have travel insurance, contact your travel insurance company to discuss your options - they almost certainly will arrange to get you physically back to your country of residence in this circumstance.
If you do not have travel insurance, take this as a very very good lesson in why to have it...
Comment: Travel insurance (indeed most insurance) is for things not under the control of the insured, so I would venture that most would not pay up under this case.
Comment: @Itai I've worked in the insurance business, including brokers which did travel insurance and also handled the claims for that insurance.  They covered this sort of situation under multiple insurance policies, so your venturing is not universally correct.

Missed connecting flight


Intercepting clicks from subview in Android

Question: My application has a custom view which contains other custom views of a different type. The subviews have their own click listeners (which I can't change, as these are in 3rd party libraries). How can I intercept a user's click at the level of my view to do some processing, and then pass the click on to the proper subview?
Answer: Justin, you can play with dispatchTouchEvent() or onInterceptTouchEvent().
Answer: I'm not entirely sure about this, but in Java what I would do is define various subview objects in my main view and simply send those to the draw/paint function.  That way I'd only have ONE click listener which would be in the view anyways.
Can you do something like that in Android?


Is the affinity of an enzyme or transporter for its substrate or solute influenced by the amino acids at the binding site?

Question: The affinity of an enzyme or a protein transporter indicates the strenght of the binding of substrate/solute. An enzyme with higher affinity binds its substrate more strongly than a counterpart with a lower affinity. Is affinity always a function of the protein structure of enzyme? If the same enzyme in two different species had different affinities for substrate, would that indicate that there were differences in amino acids at the binding sites of the enzyme in the two species?
Comment: I wouldn't say "can bind with more substrate" I would say "binds substrate more strongly" - the answers to your other two questions are yes - affinity is a function of the structure of the enzyme (as well as the shape/structure of the ligand), and yes a difference in affinities in two species indicates there is a difference in amino acids that affects the binding site. Note that it wouldn't necessarily have to be directly at the binding site, just as long as it affects the shape of the binding site.
Comment: Km can most easily be understood as the concentration of ligand that results in half saturation of its target. https://arxiv.org/pdf/1305.5533.pdf
Comment: I have edited your question to remove the erroneous description of affinity, corrected in the comment and tightened the wording. I have changed the title to reflect the actual question. I have removed reference to Km because 1) transporters are not enzymes and do not have Kms 2) Km is a parameter that is interpreted in terms of affinity, which may only partially be correct. However as your question is about affinity there is no reason to muddy it with mention of Km. Apologies to @WYSIWYG, but this seems the only way to produce a good question worthy of an answer.
Comment: @David It depends on how narrowly you define "enzyme", but transporters can indeed be treated identically to enzymes, where the reaction is converting "substance inside" to "substance outside" (or vice versa) rather than making/breaking chemical bonds. Transporters will show the same saturation kinetics as enzymes, and will have kinetic descriptions which have a term equivalent to Km. (Whether you actually call it "Km" is another question.) -- That said, the mention of Km was unnecessary to the question, and I have no issue with its removal.
Comment: @RM — That same point struck me after writing. But transporters was an odd choice. I'd have thought general ligand binding as for membrane receptors and proteins such as heamoglobin should be included, in which case you would be talking about Kd, I imagine.
Comment: @David - Thanks for bringing Kd up. I agree with what you and RM have said above. Yes, transporters show the same saturation kinetics as enzymes. e.g. - an organism can be exposed for short term with metal and its influx can be studied at different concentrations and this data can be fitted into MM equation to get Km and Vmax. Important caveat is that these Km and Vmax are blended values from several transporters. I have read that -Log of Km can be called Log Kd (dissociation constant). Higher the log Kd, stronger the binding. Would you be able to shed some light on this relationship? Thanks
Answer: In a reaction which follows a saturation kinetics, KM is basically the concentration of substrate/ligand at which the rate of the reaction is half of the maximum rate (or the binding sites are half saturated).
The biophysical meaning of KM would depend on the underlying model. For example, in the equilibrium approximation of Michaelis-Menten model, KM is same as dissociation constant (of enzyme and substrate). In the Briggs-Haldane model (quasi steady state approximation), it is slightly complex: KM = (kr + kcat)/kf.
Overall, the thumb rule is that lower the KM faster will the reaction saturate.

Is affinity always a function of the protein structure of enzyme? If
  someone study same enzyme in two different species and observe that
  the enzyme has different affinities in two species, then does it
  indicate that there might by slight difference in key amino-acid
  component at the binding sites of the enzyme between these two
  species?

Almost every property of the protein (not just affinity towards a ligand) is because of its chemical composition and structure. Although they are directly involved in binding, the amino acids at binding site are not the sole contributors to the affinity. The other amino acids that are critical for the overall structure of the protein are also important in preserving the function.
Answer: I will add to the answer by @WYSIWYG by turning your question round: "If you changed the amino acids at the binding site, would this affect the affinity of a protein for a ligand*?"
The answer to this is yes, and for an enzyme you can change the substrate specificity entirely, as one can discover from reading this review by Wilson and Agard.
However one should also be aware that changing residues at parts of a protein outside the ligand-binding site can also affect the affinity of binding — see, for example, this paper by Oue et al.
[*This makes the question more general to include other proteins that bind ligands such as membrane receptors and transport proteins such as heamoglobin.]


Bogus request paths with a single letter and three numbers causing 404s, what are they?

Question: /q873 /s106 /s833 etc. - I get these requests constantly generating a 404. They are from Google, Amazon, CERF and others. What are these people wanting? Is it a dos attack? It's useless to ban the IP as they have dozens if not 100s. Anyone else seen these sort of URLs? Thanks.
Comment: Do not worry about 404 errors unless, of course, the page should exist. Mostly weird 404s come from bad links and generally from spam sites. Will not cause you harm. DoS attacks are just that, attacks. They are unmistakable and extremely rare. A bunch of 404s are not an attack. Annoying Yes! But not an attack. I would not worry about them. They are just a part of doing business these days.  NEVER mark a valid 404 as being fixed. Just leave it alone.
Comment: "They are from Google" - If these requests are from verified Googlebots (for instance) then it might indicate a misconfiguration on your site? Googlebot is finding the URLs somehow.
Answer: Check your access logs or mod security logs if you have POST requests before these requests /q873 /s106 /s833 etc. Usually hackers try to create directories in server to test and upload shell using website vulnerabilities. If POST requests are present and block those ips. Check POST data through mod security logs to be on the safer side.
Answer: The google ones could just be search crawlers. The amazon ones could be from a snip of code somebody made on it, or amazon is crawling to create a search engine. It is okay, but be careful.
Comment: Thanks for the reply. I'm also getting 404s from REDIRECT_URL = /$$$&?&?$$$. I simply don't understand what they are trying to do? This is not from the IPs listed above. Are they deliberately trying to create a 404? Plus they are not creating them fast enough to bring down the site. And not that many. Seems like a steady stream.
Answer: Well, I found a way to get rid of the bogus URLs. It's sure nice not seeing all those 404s. Below is the code I'm using. Thanks to all who replied.
<code> RewriteCond %{REQUEST_URI} !\.htm$
 RewriteRule ^([^.]+)((/)?)$ https://example.com [nc]
</code>
Comment: "It's sure nice not seeing all those 404s." - That really depends on where you are "seeing all these 404s". In your access log this simply replaces the 404 with a 301 (and _potentially_ a 200 OK to your home page) - this just masks the problem and makes genuine reporting harder.
Comment: w3dk, what do you suggest? If I have it go to a 403 the server still logs it. So how do you actually get rid of someone so it's not a bearing on your server?
Comment: To _completely_ reduce load on the server then I would guess the only way is to implement some kind of front-end proxy server that is able to reject these requests from hitting your application server? Otherwise, a 404 (as closetnoc suggested in comments) is arguably the correct response. It's just unfortunate that the Google Search Console 404 report (if that is what you are referring to) gets swamped. The GSC reporting capability is not very good in this respect. (I meant "302" in my comment above, not "301".)


Right to published deceased mother's poetry

Question: My mother gave me a collection of her poems. She is now deceased. She always wanted to be published. She never copyrighted her work. Her surviving spouse and my brother have no issue with me doing this. Do I have to worry about any legal considerations?
Answer: First, my condolences--I hope you and your family find peace.
As for publishing her work, everything I've read emphasizes next of kin (the person who can legally act in their stead) when publishing the work of a deceased person. The person's manuscript (or computer that contains the text file, etc.) is considered personal property, and passes to the next of kin to deal with as they see fit. As long as you have the spouse's (your mother's next of kin) consent, I see no problem with you publishing the poems.
If you're still unsure or run into problems, I'd get in touch with a probate lawyer.
Comment: @Lori doesn't feel a need to... until it say becomes a huge hit and worth millions and he wants his fair share.  Best to have him sign a contract of agreement stating he wants nothing to do with the poems and will not attempt to make any future claims against it should they turn into a profit.  Also, if the poems were handed to you via a will, then there is nothing anyone can do as it was legally handed to you that way as well.
Comment: Do check that she didn't designate someone else for intellectual property in her will.  It sounds unlikely in this case, but I've seen a case of this where the person designated somebody with the right skills for the IP, unlike everything else that went to the closest heir.
Comment: Thank you. I think I'll be ok doing this as everything I have she gave to me and my stepdad doesn't feel a need to lay claim to it.


Proof of Work vs. Proof of History

Question: Can someone explain the context of what Nakamoto exactly meant with: "To implement a distributed timestamp server on a peer-to-peer basis, we will need to use a proof-
of-work system..."? I don't quite get the importance of the time aspect, since the timestamp header field seems not to be very important. Maybe someone can clearly outline, with real use cases and thought experiments, which exact problems we want to avoid to run into. Solana's proposed proof of history method (with Verifiable Delay functions) tries to exactly solve that problem.
What I don't get: why is the passing of time the only thing we really want to prove? Concise problem descriptions are essential to understand the solution and caveats associated with it.
Answer: To put it simply: digital things are infinitely reproducible with very little cost, and so if we are attempting to create a digital money system, we need to make sure that users cannot simply copy & paste their money, to create (infinitely) more money. Functionally, this means that we need to solve the double-spend problem, and to do that, what we ultimately need is a way to give all transactions an explicit ordering. If we can reliably determine the order of transactions, then we can keep track of the network's state, and ensure that no user is allowed to spend their funds more than once.
With centralized systems, this is easy: you just trust the network admin to decide what the order is, and all other participants must follow suit.
But with a decentralized system... how do you create this ordering, in a way that all participants will reliably agree upon? The solution to this problem, as provided by Satoshi Nakamoto, is the bitcoin blockchain. It is a clock, with each block being the next 'tick' forward in the network's ongoing history.
This is the crucial point that allows the network to prevent users from double-spending their funds.

I don't quite get the importance of the time aspect, since the timestamp header field seems not to be very important.

The timestamp in the block header is more or less a sanity check, and it is used to help calculate network difficulty. More info can be found here.
This timestamp is not used to order transactions though, the blockchain itself is the 'clock' that provides that functionality.
Comment: Great answer. But: why do we need 10 minutes to get that ordering done? And let's suppose someone (Alice) tries to game the system by sending several double-spending transactions. Let's also assume that we have two mining groups A and B which in total represent the network except clients. If Alice now tries to spend one of her coins several times, this could easily be detected by the nodes involved in the system, just by checking if it has been spent before. If one now says: well, but what if A receives one of the messages and B another transaction? Since bitcoin is probabilistic...
Comment: one chain in the end should be the longest; furthermore, A & B at some time know of all the transactions Alice tried to include. So it would be easy to implement to detect that behaviour and several of her transactions will thus not be included in the end. What am I missing here? EDIT: I get the need for ordering, but isn't that implicitly constructed by selfish behaviour and one blockchain winning in the end?
Comment: re: *" why do we need 10 minutes to get that ordering done? "*: the length of time isn't really important in that regard. The blocktime *could* be different, but changing it comes with certain trade-offs, you could search this site for some posts with more info on the topic. re: *"I get the need for ordering, but isn't that implicitly constructed by selfish behaviour and one blockchain winning in the end?"* yes, bitcoin miners are incentivized to create the blockchain, which provides the secure ordering of transactions for the network.
Comment: Good answer. So does that mean that all transactions in a block have effectively occurred at the same time? Presumably also that means that two transactions in the same block that both send the same coins is not possible/invalid.. because you can't determine which is first?

Proof of Work vs. Proof of History


.deb repository management software

Question: I've been searching for an user friendly solution to manage a repository for some custom .deb packages we're using inside my company. I've briefly looked over the tools listed here, but they seem to me to be just bunch of scripts glued together to do the job (some of them badly documented even).
Is there any "full-blown" solution that:

has a web interface to allow configuration and inspection of the repository (configure sign keys, distribution names, etc. basically an interface for the common operations you can perform on a repo)
allows users (based on some ACL) to upload packages to certain distributions
has hooks for events like "pre-add-package", "post-add-package", etc.

or at least something resembling that?
Answer: I've seen cobbler meeting production requirements for redhat and centos (custom repository was necessary). You might want to try it for debian.

.deb repository management software


Optimal Level of Wavelet Decomposition for Denoising

Question: If a certain mother wavelet is defined and the optimal threshold shall be defined via Donoho, how can I define the optimal decomposition level to achieve the best denoising results.
Comment: Answers have been provided. Do not hesitate to vote or accept them
Answer: Best denoising should be related to certain quality measures, often requiring the clean signal reference, which you do not have in general. Or you could rely on some reference-free measures.
To the best of my knowledge, many SURE wavelet methods allow to derive risk estimators without a reference, on a given wavelet decomposition (with given levels) in a scalar fashion, coefficient by coefficient, before reconstructing with the inverse transform.
There are a few references that address a selection of appropriate levels:

Using Stein's Unbiased Risk Estimate (SURE) to Optimize Level of Decomposition in Stationary Wavelet Transform Denoising
Optimal determination of wavelet threshold and decomposition level via heuristic learning for noise reduction
Selection of Optimal Decomposition Level Based on Entropy for Speech Denoising Using Wavelet Packet

but they seem relatively ad-hoc to me (based on a minimum of the Stein risk, entropy, genetic algorithms). It seems quite difficult to design a model of what happens across subbands.
Indeed, scalar thresholding on orthogonal wavelets often leads to relatively poor results. One generally should invest in (slightly) redundant (and oriented for images) wavelet decompositions to improve the signal/noise separation (at the cost of correlation), block thresholding to base threshold on groups of coefficients, inter- and intra-scale, and to coefficient weighting. The paper A Nonlinear Stein Based Estimator for Multichannel Image Denoising reviews previous models and   also exploits coefficients from different channels, but the block/redundancy pair still applies for mono-channel data.
[20181218: Additional notes] one should be aware that the level of decomposition combined with wavelet filter length generates globally long convolutions, that should be restricted with respect to the signal length. Side effects, like data extension (periodization) and aliasing caused by thresholding are important factors as well.
Answer: I'd say it depends on the noise properties and of course the image itself.
What you can think is that most Denoise Filters can handle only the High Frequencies of the noise.
Hence the decomposition process moves Low Frequency of the noise to the High Frequency part for the spectrum.
So if your noise is white you need to go down as you can.
If it colored and most of its energy is in the High Frequency you can do only few levels.
Comment: Sorry. Forgot to add, that white noise is assumed. I guess that it doesn't make sense to decompose as often as is possible and imagine, that there could be a criterion wrt the signal entropy or SNR, but I couldn't find sth usable in wavelet books or alike wrt the optimal decomposition level.
Comment: I'm not sure it will be easy to derive the Sure Estimator for the number of levels. Si I can't think on Analytic solution for that.
Comment: @ChaoticPolynomial, Could you mark my answer?


What happens to concrete if you add lye to the mix?

Question: What happens if you're mixing concrete and you add some lye to it? Does it make it weaker, stronger or does nothing at all? I'm guessing concrete is basic so adding lye to it might expedite the reaction, causing it harden faster?  Alternatively, it may react to with the water and starve the mixture?
Comment: It makes the cement harder faster as shown in this test https://www.sciencedirect.com/science/article/abs/pii/000888468990046X
Answer: The article referenced in the comment above (Ref 1) is not relevant to concrete. It analyzes solutions with a water to solids (cement plus $NaOH$) ratio of 1, whereas ordinary concrete seldom goes above 0.5. This is a paste, not a structural material. The $NaOH$ speeded up early hydration at 1 M, and retarded it at 2 M. It was apparently affecting the aluminates more than the silicates.
The composition of typical portland cements varies, but is usually considered to be mostly $C_3S$, a faster reactor and $C_2S$, a slower, but eventually stronger component. Ref 2

Many admixtures are used in portland cement concrete (Ref 3), but sodium hydroxide is not one of them. $NaOH$ is used as a promoter with silica-rich additives like flyash in highly modified cements, but portland cement is already silica-poor. When portland cement hydrates, $Ca(OH)_2$ is formed, which is not a really good strengthener, except that over long periods of time, it will become incorporated into the silicate gel, strengthening the concrete somewhat.
However, there are adverse reactions noted with silica-rich aggregates and the high alkalinity of sodium hydroxide (Ref 4), so it is always advisable to keep the sodium level low, whether from an alkali, an admixture, or external applications, like salt.
Ref 1: https://www.sciencedirect.com/science/article/abs/pii/000888468990046X
Ref 2: https://en.wikipedia.org/wiki/Portland_cement
Ref 3: https://www.cement.org/cement-concrete-applications/concrete-materials/chemical-admixtures
Ref 4: https://www.concreteconstruction.net/how-to/repair/chemical-attack-on-hardened-concrete_o
Answer: Cement is basically made of impure $Ca_2SiO_4$, which is made of independent $Ca^{2+}$ and $SiO_4^{4-}$ ions. When mixed with water, the following reaction happens :
$$Ca_2SiO_4  +  H_2O \unicode{x2192}Ca(OH)_2  +  CaSiO_3$$
The useful part of this final mixture is $CaSiO_3$ which has the structure of a polymer made of a long chain $H-O-(-Si(O^-)_2-O-Si(O^-)_2 -O-)_n-H$. And of course there are $Ca^{2+}$ ions near each Si atom to compensate the charges. This makes a long chain of covalences $-Si-O-Si-O-$  and this is why the concrete is so hard and so resistant.
However to be correct, one should not write $CaSiO_3$ but rather $Ca_n(SiO_3)_n$ and the previous equation should be written : $$n Ca_2SiO_4  +  nH_2O  \unicode{x2192} nCa(OH)_2  +  Ca_n(SiO_3)_n$$
To go back to the question of User148298, one sees that $Ca(OH)_2$ is a by-product in making cement. So it no use adding it to the original cement. It does not help.
Comment: Isn't lye Na(OH)2?  Your point still stands.


Adding a ground to a GFCI ungrounded outlet box

Question: I have bought a 1974 built Condo that had GFCI issues.
 A bathroom has a GFCI outlet and no ground wire attached. It has a red/white wire hook-up that functions properly.
 There is a metal box, however it not attached to anything at all. It just flops loose in the wall opening having a hole in the vertical 2x with just the wires running through the hole. A previous owner tiled the entire bathroom and the electric box 'ears' are behind the ceramic and tension the cover into place. It fails the ground test needless to say and the inspector wants it fixed for occupancy.
 The red/white wires seem to come from the light bar.
 Should I remove the light bar and try to fish a ground-wire up to a proper metal box there if there is one?
 If so, is there a test I can do to check for ground-ability?
 Getting to the main light switch from the outlet would be a real trick.
Answer: GFCI with no ground is OK, though it should be labelled as such. The GFCI provides better safety than the ground would have.
In fact, installing a GFCI is a common fix when better safety is needed but no ground is available; I have three installed for exactly that purpose.
Comment: You need to find out what the actual concern is. Get specifics from whoever did the inspection. If local code absolutely demands a ground, you will have to either find some way to get an acceptable ground there .... or dismount the outlet, properly cap the wires, cover the opening with a blank plate, and accept not having an outlet there, if that meets code. First step is to find out __exactly__ what the inspector's complaint was.
Comment: Thank You Keshlam, However currently there are already 2 GFCI's in place that fail the inspectors test, which I need to pass.
Answer: As to the loose box, a metal box should be grounded, but you can replace it with an "Old Work" plastic box. Just a few bucks. However, if you have to fix the ground connection (Not an NEC requirement as long as it labeled "No ground"), and you only have two wires running to that box, then your best to run new 12-2 romex to where that wire originates and make sure the wires are connected properly
Answer: If you have a GFCI outlet, it can accept a three-conductor grounded power cord. Therefore, that outlet must be electrically grounded. The only time an ungrounded outlet is permissible is when no ground connection is provided and only a two-wire power cord can be plugged into it.
Non-GFCIs are forbidden in bathrooms. Therefore, you cannot use a two-conductor outlet because nobody manufactures a two-conductor GFCI.
If this were mine, I'd open the light bar and look for a ground there. If one is there, it'd be an easy enough job to fish a bare copper down to the ungrounded GFCI outlet. Failing that (no good ground in the light bar), I'd try to find a way to drill up into that wall from the basement (assuming 1st floor), from where I could fish a ground wire to the outlet. Failing that, I'd cap off the wires in the outlet and cover it with a blank plate.
Comment: Uhm... not so, in my experience. An ungrounded GFCI, _labelled as such_, is considered acceptable. Having a ground is better, but is not mandatory in all places. See David's answer as well as mine.


Why doesn't QE cause the federal funds rate to continue decreasing?

Question: Quantitative easing (QE) is essentially a large-scale form of open market operations, in which the Fed buys large amounts of treasury bills of all maturities (ranging from 1-month to 30-year) and mortgage-backed securities from commercial banks. By doing so, they are crediting these depository institutions with large amounts of electronic money. Thus, wouldn't there be a large expansion of the supply of federal funds in the federal funds market as a result of QE? And hence, wouldn't the federal funds rate keep on decreasing, even below zero, as the Fed's massive "QE infinity" programme continues?
Comment: Regardless of how much money I put in your bank account, it does not incentivize you to lend out your deposit at a negative rate (unless your deposit is charged a negative interest rate, as in the case of, e.g. the ECB, Swiss National Bank, and Bank of Japan).
Comment: As for open market operations, the Fed distinguishes between temporary and permanent OMO's. Temporary OMO used to influence the fed funds rate involves overnight repo agreements. On the other hand, permanent OMO used to implement QE consists of outright purchase of securities.
Comment: @Michael So you are saying that if the Fed really wished to lower interest rates even further, they would have to engage in more overnight repo agreements? I presume that since interest rates are now in a window between 0 and 25 basis points, the Fed is no longer engaging in overnight repo agreements?
Answer: At the time of writing this answer, the Federal Reserve pays 0.1% on reserves: link to Fed webpage.
Banks have no incentive to lend Fed Funds at rates below 0.1%, as they can keep the excess reserves and earn a higher rate of interest.
Interest rates are largely set by price signals made by central banks, not quantities.
Comment: The 0.1% is an administered rate, fixed by the Fed. They can put it at whatever level they wish.
Comment: Yes, so price signals would be from changes in demand and supply right? So if supply increases massively, wouldn't there be a price signal downwards, instead of it remaining at 0.1%?


How can I get an idea on relevance of my data?

Question: I have a lot of data from my PhD, which I believe confuses my supervisor quite a lot. Therefore, he is hesitant to publish them for now. How can I get good academic feedback on this data without submitting it as a paper?
Comment: If it confuses your supervisor, chances are that it will confuse other people too. It is your job to extract a meaningful story from those data, and then present them. If it makes sense there is no reasons why he would refuse to publish it.
Comment: Seems more like a time of reflection than publication. Especially if you are both a bit confused.
Comment: Do the data confuse you?
Comment: In some way yes, it confuses me but I believe we can make a story out of it. As I am not experienced that much, I don't know what would be missing to support my story.
Answer: Talk to as many people as possible about your work
This can be in formal settings, such as a poster or oral presentation at a conference. You could also ask to give a presentation to colleagues within your department. Or it could be informal, such as chatting at a coffee break or after a seminar with fellow researchers.
It's often tempting to hold on to your work and only present it when it feels "finished", but these early stages are often the most useful ones to get feedback. So you need to be brave, and accept that there may be flaws or complications that you've not yet thought of. That's why you are doing it.
Comment: Don't you find this dangerous? The hidden finding or even the data can very well be stolen if you give sufficient information to be able to get a suggestion about what those data means.
Answer: If you don't have a good feeling for the relevance of your data, and your advisor is "confused", then now is not the time to publish.
Also, "data" itself isn't necessarily what you're looking for. To quote Alan Wilcox, former editor of Epidemiology:

Data do not speak for themselves. They need context, and they need
  skeptical evaluation.

It sounds like you don't have that context, or that skeptical evaluation. I would suggest that the first thing you need to do is get with your advisor and come to a coherent understanding of your data before you try publishing it. An attempt to just dump data you and your advisor don't fully understand into the literature will do neither you nor the field much good.


user authentication authorization community cloud force.com sites

Question: How does user management (authentication / authorization) work when we expose a visualforce page and apex code including controller etc. to community users using public sites, force.com sites.
Answer: To create customer users:

Create a new contact.
On the contact detail page, click Manage External User, then Enable Customer User.
Edit the user record for this external user.
  Select the appropriate profile. The available profiles are limited to the Customer Community User profile and any profiles cloned from it.

A more detailed description with related info links can be found here
https://help.salesforce.com/HTViewHelpDoc?id=networks_create_external_users.htm
Answer: Users can be added from contact using "Manage External user" button or apex code. When a community is created, a corresponding site is also created. Pages that you want to show as public can be added to the pubic access setting of the site. Access inside the community is controlled by community administration settings and community user's profile/permissionset


What is the difference between the two sensors?

Question: I am working on a project which requires the use of sensors and i don't know which one to use so i would like to know the difference between the two.
Comment: It would be helpful if you would provide spec sheets or at least part numbers and sources for the 2 boards. Otherwise we have to do some guesswork from the images provided.
Comment: They seem pretty similar. One uses surface-mount components and the other through-hole components. But my guess would be that they do pretty much the same thing. I'd prefer the first one, as it have some bypass capacitors on it, which could make it's signal a bit more stable.
Answer: Apart from the obvious construction and component differences the two sensors seem totally equivalent from their look.
They seems to both be FC-51 modules: those are "line followers" meaning one diode (the clear one) emits infrared light and the other (the dark one) measure the amount of IR light reflected by the surface in front of them.
The potentiometer is there to determine the triggering level so that when powered you can have a LOW signal on the OUT pin when the threshold is reached.
Comment: How do you know, that the output signal is digital? Wouldn't it be also possible, that the output voltage may be analog and the potentiometer controls the gain? I don't know, how I should be able to tell from the pictures.
Comment: Because those sensors are quite common and called FC-51 https://codetipste.blogspot.com/2017/04/ir-sensor-arduino.html?m=1.
Comment: Not to mention I stated "they *seem* totally equivalent *by their look*": without further information that is my best guess...
Comment: Ah, ok. Good, that you included the part number (FC-51), so that we have a reference. +1
Comment: How can i find the positive and negative terminal of transmitter and receiver of sensor in first pic?@RobertoLoGiacco
Comment: Power it up and use a multimeter maybe?


Is Vegeta now able to turn into God of Destruction mode just like Toppo, or he can just use hakai?

Question: In the Dragon Ball Super anime series, when Toppo used hakai he had to turn into God of Destruction mode. Now that Vegeta has been taught hakai, does this mean Vegeta now  is able to turn into God of Destruction mode just like Toppo, or he just can use hakai?
Answer: They are separate things.
Toppo was able to use the God of Destruction Mode due to being the candidate to be the next God of Destruction.
But you don't need to be a candidate to use Hakai, as demonstrated by Goku against Zamasu:

After achieving Perfected Super Saiyan Blue, Goku is able to perform the Hakai to a limited degree, however, it's much slower than Beerus', destroying Fused Zamasu progressively and requiring concentration throughout - thus Fused Zamasu takes advantage of the weakness by using Future Mai as a human shield, stopping the technique.

But yes, Vegeta can use the transformation, as demonstrated at the end of Dragon Ball Super #74:


Port MessagEase Macro to new device

Question: I have a new phone and a lot of MessagEase on my old phone. Unfortunately, they haven't been transferred with the default process to migrate to a new device.
Is there another way to port them over apart from copy pasting every single one?
Comment: You might wish to take a look at our [adb tag-wiki](/tags/adb/info). If the app doesn't block backups, you could simply `adb backup` it from the old device, and restore it to the new using `adb restore`. Piece of cake if you've got ADB running – but if you did not yet, the tricky part is setting it up (if you're on Windows that is; it's not that difficult on Linux).
Answer: Note: I wanted to post this as a comment, but have yet to reach the requisite reputation requirement; I'd appreciate if someone can move this for me, or if not just ignore me, thank you!
I double checked and MessagEase does indeed have the backup flag enabled in its manifest, so as @Izzy pointed out ADB backup should be a viable method to export them all (personally, I am still having issues with the ADB restore function, just be aware it may not throw any error messages from syntaxical issues by default, and do some further reading on how to troubleshoot).  If you do wind up having to do it manually, note that holding down the hand icon key with a keyboard's hex data on-screen supposedly brings you to the keyboard exchange step and imports it (according to the app's FAQ, I have not tried the feature myself); that might help cut down the labor/time a bit.
Additional Thoughts
I initially thought maybe one might be able to find where all the hex values for keyboards are being stored in some directory in root, but apparently it's a bit more complicated for IME/input devices than I'd assumed.  Someone else more knowledgeable might be able to advise on locating such a directory (or potentially in a .db?).

Port MessagEase Macro to new device


Is it a sin for a job holder wife not taking proper care of husband and child?

Question: If a wife is a doctor who works outside, thus cannot take care of her husband and child properly. Will it be sin? When the situation is that the profession of the wife is hampering her duty towards her family, can the husband stop his wife from doing outside job?
Answer: There could be several points concerning what you inquired:

Is it a sin for a job holder wife not taking proper care of husband
  and child

Such as:

Based on Islamic evidences, (at least based on Shia's viewpoint), it
is permissible for women (wives) to work out of the house (by
observing some items…, aside from some limitations in doing that…)
The husband cannot force or make the wife to do the house's works
(although it is better if the wife do the works herself without
forcing…). In the meantime, it shows how much Islam pay attention to
women rights…

According to Imam Khomeini (Ayatollah Khomeini) as a Shiite Marja'-al-Taqlid as the response to the following question as it has been asked:

If the husband didn't deem it (working of wife out of the home)
  advisable, and being employed of wife causes to break up the married
  life, "can the husband prevent her wife to work or not?"
Imam Khomeini (Ayatollah Khomeini) replied:
Being employed for the wife is no impermissible, but it is related to
  the right (permission) of the husband if she wants to get out of the
  house.

For more info. I strongly recommend you to read the reference below which relatively is considered as a perfect relevant source. (If you are familiar with Farsi (Persian))

Reference:
www.wikifeqh.ir
Comment: Thnx a lot @Seyyed . It become very clear now to me. All praise to allah to gave us such nice solution to lead a life of love and peace.
Comment: I dont see any straight cut answer here. Again husband cant force wife to do household work then what a women should do? she is not responsible for earning , she is not responsible for household work. Does islam tells woman to sit idle whole life if they wish?
Comment: Uh, no dear Zahan. It doesn't mean that. Haply it seems Islam ask the wife to do the works of home freely not in force. Besides, there are lot of reward (thawab) for working of wife based on the hadiths. But as I told you before, Islam wants to shows the wife that she is not limited a lot...
Comment: Besides, dear mate, you'd better notice to the mentioned quotation that said "...but it is related to the right (permission) of the husband if she wants to get out of the house", what does it mean? it can be inferred from it that Islam ask the wife (indirectly) to be under the permission of her husband as it is said that "the wife needs her husband's permission if she intends to get out of home". Then I reckon it doesn't mean what first you inferred. I admire your paying attention to this nice point. I am at your service dear mate for more question as much as I know... good luck.
Comment: uh-huh, now you are right. I'm glad that you didn't look at the mentioned matter on bias. God Bless You. Good luck dear mate.


Employer Letter for NRI Home Loan

Question: Please advise: for an NRI working in US applying for home loan in India,  Bank is asking for employer letter, latest salary revision letter from employer and employer ID card etc.. but if NRI is an independent consultant, how do we produce these docs, where there is not an employer but only clients. Please help advise on this subject, can applicant self
adress these letter/ docs etc...thanks
Answer: The documents asked are the standard documents requested for approving home loan.
Inform the Bank of your status as NRI. It would help if you show your NRE/NRO accounts and funds in them. Quite a few Banks go all the way to give a loan to NRI as they consider that repayments is less risky than someone in Indian salary.
Also showing them the US Bank Account statement for a period of year or so will also help you get the loan.
Comment: Thanks for the advise, could you suggest some examples of such  banks that like you have mentioned that will provide loans for NRI more readily. Thanks for all your help!
Comment: Go to any large Public Sector Bank or Large Private Banks, they have special NRI cell and red carpet waiting :)
Comment: I am having H DFC , AXIS, ICICI, AN
Comment: And SBI in order listed Hope I am on right track of choice - greatly appreciate ur comments thanks
Comment: Yep anyone of these should welcome you. Good Luck :)

Employer Letter for NRI Home Loan


Extensive form games (pure strategies)

Question: Why do we include actions even on nodes which will not be reached if the strategy is followed, while defining the pure strategies of an extensive form game?
Comment: Does the answer to this question (https://economics.stackexchange.com/q/15747/42) help?
Comment: Because we care about the behaviour of the agent in every node of the game. We need to know the actions that are off the equilibrium path, even the probability to reach this branch of the tree is zero and these actions are non credible, because it tell as about the agents rationality. In most games we do not have the chance to know all the actions that are possible to be followed by some or all the agents, so we can not have a clear vision about the instrumental rationality in any possible path of the game (even those that are not subgame perfect).
Comment: Think of those actions as threats: "if you deviate and do x then I'll do y." Thus, subgame perfection is in a sense a refinement of NE that formalizes the idea of a credible threat.
Answer: Think about a player (female) that moves first and is considering the profitability of deviating. Let's say that according to the strategy she is supposed to play action $x$ and then the second player (male) is supposed to play action $a$. It will not be correct for the first player to think that if she instead chooses $y$, the second player will necessarily still play $a$. Remember this is a sequential game, so after seeing that she chooses $y$ instead of $x$ player 2 can also deviate to some other action,  say $b$. Therefore, by specifying the actions that each player will take in each node (even in the ones that are not supposed to be reached according to the strategy) we completely specify the strategy of each player, and can correctly check that no player has profitable deviations.
In fact, in many games, the only reason why the player that moves first chooses an action $x$ is because of the response of the other player after observing $x$, and the knowledge that choosing something else will also affect the decisions of other players, etc.
In a practical example, if you are playing chess and consider moving your queen to get one step closer to eat an important piece of the other player, you must anticipate they will react to this movement and protect their piece, or attack something more valuable of yours, etc. This is why when thinking about the strategy of the other player you must consider how different they will react depending on which piece you move next and to where.
BTW, chess is really hard to fully specify as a sequential game precisely because the number of possible nodes is massive, and properly specifying a complete strategy for each player has proven extremely hard. However, hopefully it gave you some insight of why actions and strategies are not the same things in an extensive game.
Comment: No problem :) welcome to the site.
Comment: Thank you, this clears it.
Comment: Great, in that case, would you mind marking the answer as accepted?
Comment: I am sorry, I did not know I was supposed to do that. (New to this).

Extensive form games (pure strategies)


Create Intake List

Question: I would like to create a list in PWA so that I can have users fill in the information that I need in order to create a new Project.   I don't see how to create a new list that is not attached to a project.  Any ideas?   This seems quite basic.   Is this documented somewhere?  I could not find on technet.
Comment: You mean creating a custom list?
Answer: You have mentioned in your question

I would like to create a list in PWA so that I can have users fill in
  the information that I need in order to create a new Project.

So it's not just a direct custom list, you need + one trick that is "Create Projects Option" as I mentioned below,

At any site below the PWA root site, Click on the Site Setting icon,
Select add a new APP.
Create a custom list with at least the mandatory fields of Project custom fields.
Add a new item to your list, select your Item.
From the above ribbon,  at Item tab, click on the Create Projects

Map your list field with your project field in order to create a new Project from list item

For more details check my article at Create a new Project based on SharePoint List Item in Project Server 2016
Answer: Following instructions from the Project online.

Go to the project online root site.
Go to the site contents from the gear icon.
You will find a '+ New' option to create a List/Library/App/Subsite.
The 'List' option used to create a new list.

Make sure you have at least Edit rights on the site.
Let me know if I am out of your questions.
Comment: I think you are wrong
Comment: He wants to create a list to collect project details before project creation which is not related to projects.

Create Intake List


How to get Pokemon Sun save file from an old SD card?

Question: I had a Pokemon Sun save file that I had found on my SD card for my Nintendo 3DS. I transferred it over from the old card to the new one, and deleted the save from the newest SD card. I went back in and my old save wasn't there. I'm very upset about this and I don't know what to do.
Answer: I can only assume you are using the e-shop version and not cartridge. To my understanding, you were trying to transfer the save data from one SD card to another. To that, I say there is no need. If the SD card works, just use it. If not, a quick Ctrl + A, Ctrl + C is the most reliable method of backup.
If you have a new 3DS system or something of the such, you should be able to plop the old SD card into the new system. Once you log in and download Pokémon Sun, everything should be there.
Another bit of advice to you, do not delete anything until you know for sure that everything is working. This applies to everything you do. This way, if something goes wrong, you will still have the original files.
Unfortunately, I don't know exactly what you touched. If you are asking how to recover files, I'm sorry to say, they are gone for good. However, since it isn't clear what specifically you tried to move, there is a small chance that your issue is fixable. We will need more specificity than just "I transferred my save over from the old card to the new one."


washing your hands and forgetting

Question: If you wash your hands and your mind goes blank and you dont remember if you said a bracha or not. do you make a new one? Do you wash again and then make a new one?
Comment: I say if you had that much hesech hadaat you probably need to wash again midina!
Answer: The general rule with berachot is safek berachot l'hakel- in a case where we are not sure whether we make a beracha we err to the side of not making another one. This is a subset of the general rule of safek d'rabanan l'kulah (we are lenient about doubts which occur on mitzvos from the Rabbis.)
The exceptions are berachot that are d'orayta "from the Torah" which are bentching (grace after meals) and birchat hatorah.  However, one would be covered by the bracha of ahava rabba before shema in the morning if one was not sure about birchat hatorah and would not say it if one has said or plans to say that bracha.
Therefore you one would not go back and wash or make a new bracha.
Comment: +1. But a clarification: Bentsching is often, but not always, required by the Torah.
Answer: I would think that if you know for sure that your hands are now tahor, then there is no problem.  You washed your hands in order to purify them, so even if you didn't say a bracha, your hands would still be tahor.  The tahara is taluy on the netila, not on the bracha.
In my opinion, I would think that someone should be nervous about washing one's hands and saying a bracha on the netila could be a bracha levatala.  What if your hands are still tahor since the last time you were notel them?  Then what happens is that you are notel them again and you say a new bracha - that would be a bracha sh'eino tzricha!
Comment: @Vrahm, I was not talking about keeping them naki, I was talking about keeping them tahor!  And also, are you saying that someone who has Attention Deficit Disorder would never be able to wash his hands properly?  Maybe that is why chazal said teichef lenetilas yadayim se'udah.
Comment: i thought that is why they say it is hard to have concentration anymore in things like shmoneh esrei and having kavana there.

washing your hands and forgetting


Word/Expression corresponding to 'good afternoon'

Question: As far as I know there is no greeting that corresponds to the English 'good afternoon'. I also think 'bonjour' is still used in this context.
I think Bon(ne) après-midi is only used differently (that is, when leaving someone; e.g. je te souhaite un(e) bon(ne) après-midi).
Is there a reason why this happens so? Why one cannot say bon(ne) après-midi even as a greeting (i.e when meeting somebody)?
Answer: I don't know if there is a good reason but:

"Bonjour"
"Bonsoir"

are used when meeting someone while

"Bonne journée"
"Bon/Bonne après-midi"
"Bonne soirée"
"Bonne nuit"

are used when leaving someone
(I don't think I ever heard "Bonne matinée")
So you're right, there is no equivalent to 'Good afternoon' as a greeting and 'Bonjour' is usually used even in the afternoon. Note that I can only speak for metropolitan France.
Answer: There is no reason why you can't from the point of view of what the practice in itself represents — in itself this greeting is just as justifiable as "bonsoir" and "bonne nuit" —, but there are certain reasons why you might not want to do it, why you might not want to be a pioneer.
You can't say it and give people the impression that what you are saying is something that they can relate to, simply because nobody does it and so nobody is used to it. One of the problems is that given a usual greeting, people know how to react because there are  phrases which are more or less set phrases that correspond to it and because they have been trained in various ways to do that. In the case of "Bon après-midi" there is the obvious reply that consists in saying "Bon après-midi" but as people do not recognize the greeting as one of those they've learned they are bound to hesitate or simply conclude that they don't understand well what you say or that simply you  don't know too well and are making an error that you'll soon correct (in other words that you  shouldn't say it)  — although I think that on account of the rather obvious nature of the words some might reply in the way I suggest.
It is quite possible that after having used it with the same persons for a while, after a few occurrences of getting no reactions, some people should find it quite acceptable to answer you with a "bon après-midi". Here, again, the usage has to start somewhere, so why shouldn't you be the first? Nevertheless, there is the possibility that you should fail; you face then the situation of having to change your habit for another one (an accepted one), and this is not the kind of behaviour anyone can adopt lightly; rare must be those people with a  certain  philosophy of life who are undaunted by such a perspective.
You might say that you can't say it because people do not relate to it and by doing so you run the risk to create  relationships that are bizarre and that in the end, if people are not responsive, you might be doing yourself much of a disfavour by displeasing them.


display related data from Community user/Contact in Site.com

Question: I am trying to create a splash page for my Customer Community using Site.com. I've got most of it set up and it looks fine. I wanted to add a section that shows data from a Related object (Affiliation) that is linked to Contact records. I'd like the data to only display the related Affiliation records based on the Contact of the logged in user. I have a data connection element, and I can filter it by Logged In user, but I can't figure out how to link that to the Contact record of the user to then filter/display only custom objects related to the Contact. What am I missing?
Comment: For others who might be interested, I created nested repeater elements. The first repeater was the User object and filtered by current User. Then my next object was able to be filtered by Contact ID from the parent repeater.
Comment: It turned out that I had it set correctly, I just had to test as a logged in user rather than as the administrator (which showed all). Once I logged in as one person everything filtered appropriately.
Answer: What you're missing is that Community users are not Contacts, they're Portal Users. You'll need to use their Portal UserId to obtain their ContactID.


What can I do to make a Dwarf Cavendish banana plant thrive in my apartment?

Question: I currently live in New York. I'm interested in having a Dwarf Cavendish as a indoor houseplant, in my apartment.  Will it survive/thrive? I can definitely provide sufficient humidity. I know having a house with a patio is much better but I don't have that.
Comment: How much light do you have? And is it sunlight? Do you fertilize? How large a container is it in?
Comment: @J.Musser I have a sufficient amount of light in my bedroom. It is sunlight, I do fertilize with miracle gro fertilizer, the container is not that big but I don't have the measurements
Answer: I have a few concerns, each of which may not be huge things, but together they can take a toll on your plant's health.

Room: Do you have enough room for it? These are big plants when mature, and even if it isn't touching anything, if the leaves are constantly getting brushed against, by people walking past, etc, that will hurt your plant. It should generally be left undisturbed.
Household dust: Dust, even if it looks like a thin layer, can be very detrimental to the plant's health. It cuts more light than you'd think, and clogs/blocks stomata. You will need to wash it off. A room-temperature, thorough shower is highly beneficial once a month, if practical.
Water quality: If you have chlorinated water, don't water with it. Even softened well water is hard on bananas. You can kill the plant slowly that way. If you can use rain water or distilled water, that would be great.
Vents: If you have a central air system, do not let air movement from any outlet blow directly at the plant. Summer AC and winter heat are both extremely drying, and you can easily burn the leaves with either, even if you have a humidifier going on. Keep it away from any air outlets, or any drafty doors/windows. These plants like consistency.
Propane/natural gas: This can kill the plant, and even small quantities will be damaging. If you have a gas oven/range, gas fireplace/heater, etc, that can easily be an issue.

I've seen some very healthy banana plants grown as permanent houseplants, and I think if you stay consistent and take care of all the plant's needs, it will be very happy for you. Might be a bit until it flowers, though.
Answer: Musser's given an excellent answer, but there's a few other factors you should consider for your big potted plant: Miracle gro comes in a variety of different NPK formulations. You might want to check online for what formulation your type of banana, or bananas in general favor. Also, premixed fertilizers are usually sold without Calcium and Magnesium salts as they tend to make other nutrients precipitate.  IIRC New York City water has plenty of calcium, but consider occasionally adding a tablespoon of Epsom salts (MgSO4) per gallon to your watering mix. Chlorophyll and Rubisco both require Mg++ to function properly. Happy green chlorophyll is required to harvest energy from light, and Rubisco is required to convert CO2 from the air into the sugars from which the plant makes everything else it needs.


How Do I know What To Use For Killin'?

Question: So I'm playing Castaway, and I eventually earn some quest items, such as the Beetle Shield and the Fire Scimitar.  Unfortunately, in this game, there's no way to view the stats of an item, other than in the shop.  How do I know how these items compare with the others in the shop?
Comment: This question has an excellent title.
Answer: Those stats in the shop aren't the items' actual stats. They're the stats relative to your current equipment's stats. So, all you have to do is equip the unique item that you want to compare and visit the Blacksmith to see how much better/worse every item sold is. There is a bug however that the stats in the shop won't know that you have stuff equipped right after loading your game until you enter an area and come back.
If you want to compare two quest-rewarded items, you can equip one, look at your stats and then equip the other one. (That's assuming that there are more than one item per equipment type. I'm only roughly 1/4 done with the game.)
Comment: Okay, I got the Fire Scimitar. It says when you hover over it in your inventory that it has a 10% chance of casting Flame when you use it.
Comment: I figured that much out.   What about, say, the 'magical' stats on the *Fire Schimitar* ?  It's weaker than the second sword in the shop, but it does fire damage every now and then.  Is there a way I can see **these** stats?
Comment: I wouldn't think so, but I don't have that yet.

How Do I know What To Use For Killin'?


Automatically connect to shared device when detected

Question: Here is my need : I want my media center to be mounted in the /Volumes of my Macbook as soon as I turn it on.
So, I need to automate the Connect as action.

Users & groups > Login items only resolve one part of the equation : mounting the macmini on laptop startup.
How to silently establish connection if I boot up macmini while laptop is already running ?
Update:
http://www.kristijan.org/2010/11/automount-afp-shares-in-osx/ explain how to mount a volume using automount command.
Still, is there an event "Share just appeared on network" emitted somehow by the system that I could plug into to trigger when to execute the automount command ?
Comment: Are you familiar with Apple Script?
Comment: I would accept solutions based on apple script :)
Answer: You should definately check out google first.
I'm guiding you in the right direction:
This is a start click here.
Comment: Meh :/ That does not correspond to my problem : no SMB share & Active directory involved here.


Serialize Entity Framework Objects Without Lazy Loading

Question: I have a very specific scenario that I'm not sure is possible to fully support:
I have an ASP.NET application that uses Entity Framework 6.3 for it's data management.
I also have a generic audit library that I use to log when specific types of data are viewed. This library is designed to be ignorant of the data/objects it logs. I would like to log entity framework created objects in json serialized format.
The issue I am running into is when I attempt to serialize Entity Framework objects with virtual references. The serialization process will trigger a lazy load on all virtual properties.
There are a few solutions that will stop this:

Disable Lazy Loading for an EF Context:
public SomeContext()
{
   this.Configuration.LazyLoadingEnabled = false;
}
Create a DTO from the Entity Framework Object and serialize that instead.
Project the data into a new type when reading from the context.

Unfortunately, options 1 and 3 are off the table. I can't go back and modify the context to satisfy the needs of the logger for various reasons, one of which is that I am not the "owner" of the projects I'm modifying. Same goes for changing the data types returned.
Basically I am trying to enter logs without impacting the functionality of the application whatsoever.
That leaves option 2. I could create a temporary DTO, log that, and then dispose of it. The problem with this approach is that whoever is adding the log references would need an understanding of the objects to create a DTO. I guess I could use something like Automapper to assist with this, but again, it's definitely a lot more work just to get around the fact that we cannot simply serialize the EF object.
My question is, is there an option 4? Is there a way to serialize an EF object without triggering the lazy loading while also not impacting the way the application current works?
Perhaps I could do some reflection into the EF object and do either copy the object or more directly direct the serialization.
Answer: Here is my suggestion.
Create another partial class for one of your Entity classes.  Include in your partial class a Serialize() method that only serializes the fields that you want, and excludes those fields that are lazy loaded.
When you've figured out how to do that reliably, either write by hand new partial classes for each of the remaining Entity classes, or create a T4 class that generates those classes for you.


Jasper's full name in the Twilight movie

Question: Why aren't Rosalie and Jasper surnamed Cullen? I can't understand why they are Hale and not Cullen.
Answer: Everyone believes that all the Cullen "kids" are adopted.  Alice, Edward, and Emmett go by the last name "Cullen" while Rosalie and Jasper go by "Hale".  I agree with Zoe that it makes sense that, since Alice and Jasper are obviously in a relationship with each other and Rosalie and Emmett are in a relationship together, it would bring more attention to the family if it was suggested that they were dating their siblings even if those siblings were adopted as well.  Additionally, it sort of makes sense to have Jasper and Rosalie share a name and pretend to be real siblings since they look similar (both have blond hair).
Interestingly, Jasper's real last name isn't Hale anyway...it's Whitlock.
Answer: Probably because it would be weird for Jasper and Rosalie to be 'dating' their siblings, if they were all Cullens.


Is there a software that simulates a pen and paper?

Question: My university requires us to scan homework to PDF and send it via the website, and I have a problem using paper because my writing is messy. I saw some students using an iPad or a Chromebook to write directly on a PDF ,using the pen with the device, and it looks so clean and if there is a mistake they can always press Ctrl+Z.
I'm using an Acer Laptop with Windows 10 Home without a touch screen, Is there a software that lets me write PDF files with a mouse that is close a real life pen effect ( I searched online for softwares and there is a lot of options and I can't test them all), other than getting a new device?
Comment: Maybe use LaTeX and one of its front-ends (no experience with front-ends).
Comment: You want to buy a graphics tablet. Huion sells really good hardware at a reasonable price. Different categories, best are the ones with buildin screen, so the "kamvas" devices. Can't get more "pen like", actually it _is_ writing with a pen.
Comment: You are looking for a wacom tablet. https://www.youtube.com/watch?v=hQ79w0ibytg. Details: https://estore.wacom.com/en-US/one-by-wacom-small-ctl472k1a.html
Comment: writing or drawing with the mouse is even worse. I don't have too bad handwriting but I always struggle with my mousewriting. You can use a handwriting font and type with the keyboard
Comment: @phuclv I'm gonna be mostly writing math with it, calculus, linear algebra, and discrete math, for a year. My main problem is with tidying and not writing in a straight line..
Comment: if you're writing math then it's an [XY problem](https://meta.stackexchange.com/q/66377/230282). What you should use is LaTeX
Answer: I'm not an expert on this and I'm not affiliated with the software but I would recommend you use Adobe Acrobat to write on the PDF directly on the digital document. The Adobe reader is free to download use and can be used to annotate like highlighting, putting x marks or checkmarks, adding a line, adding text, a circle or a dot, and of course, signing as if it was a handwritten signature. But if you want to do more freehand writing and free-form drawings around your document, you need to purchase the pro version. The Pencil tool creates free-form drawings, and the Pencil Eraser tool removes the pencil markups. Here are more details from their support page: https://helpx.adobe.com/acrobat/using/commenting-pdfs.html
Answer: All current versions of PDF-XChange Editor will allow you to do this.
Simply go to the Comment menu and select the Pencil tool.  There is also an Eraser tool for your convenience.
You can customize the toolbars to place those tools on any toolbar of your choosing, or even a brand new custom toolbar.
I have personally used PDF-XChange Editor, and I find the quality of the product to be very high.
Answer: Perhaps reMarkable can be your solution.

Convert your handwritten notes into text

All your notes, organized and accessible on all devices

Take handwritten notes, read, and review documents

Take notes directly on PDFs

Paper-like writing and reading

Integrates with Google Drive and Dropbox

2 weeks of battery life

Subscribe to Connect to access all other features

Here is the video


Why must traveling waves have the same amplitude to form a standing wave?

Question: I understand the reason for which the wavelengths of the incident and reflected waves must be equal: otherwise, the interference at any fixed position would be constructive at some instants and destructive at others. But why can't two waves of differing amplitude produce a standing wave?
Comment: Related question and discussions [here](https://physics.stackexchange.com/q/458906/179151)
Answer: If the travelling waves have the same amplitude then the net rate of transfer of energy at any point is zero and there are stationary positions where the standing wave has zero amplitude - nodes.
In the following animation$^\dagger$ the amplitude of the reflected wave is the same as that of the incident wave.

If the travelling waves are of unequal amplitude then there is a net transfer of energy.
If the amplitudes of the two traveling waves are $A$ and $B$ with $A>B$ then you can think of the superposition of the two travelling waves as being the sum of a standing wave formed by two travelling waves of amplitude $B$ and a travelling wave of amplitude $A-B$.
In this animation the amplitude of the left travelling (incident) wave is larger than that of the right travelling (reflected) wave and so there is a net transfer of energy from left to right.

If you look carefully using a vertical ruler as a marker you will observe positions of maximum displacement and positions of minimum (but not zero) displacement.
The graph bottom left of this video shows this maximum and minimum displacement by overlapping the wave profiles as time progresses.

$^\dagger$ Frames for the animations were made with Mathematica code available here, then combined into GIFs with ImageMagick's convert command.
Comment: @CarlWitthoft Is it really a dc (fixed value) component?  Is it not a standing wave modulated by a travelling wave?
Comment: S.McGrew would say the second case is also a standing wave based on comments/discussions [here](https://physics.stackexchange.com/q/458906/179151). You have made the argument much better than I was trying to.
Comment: The second case still has a standing wave, plus a DC component.  Shortly thereafter you will discover nonlinear crystals and Second-Harmonic Generation.
Comment: @Farcher you may well be right.  Over in optics-land, the frequencies are somewhat higher and we look at the situation a bit differently.
Comment: All of the images from [the Acoustics and Vibration Animations](https://www.acs.psu.edu/drussell/demos/swr/swr.html) page have a clear statement at the top that they cannot be used in other websites... I know they are handy, but they shouldn't be put into answers without [contacting the author and getting explicit permission](https://www.acs.psu.edu/drussell/Demos/copyright.html).
Comment: @tpg2114 I've replaced the animations with very similar ones I've generated myself. The licensing of the original ones seems too uncertain to mess with.
Comment: @Ruslan Many thanks and very impressive. I think the animations help to explain what happens.
Answer: You can think of this in a different way. Suppose you have a standing wave made from two oppositely-directed waves with equal amplitudes. What if amplitude of one of them reduces a bit? You think the sum should still be a standing wave. OK, but what if you continue reducing the amplitude down to $0$? In this case you'll be left only with a single traveling wave, which is not a standing wave anymore. At which point should the standing wave switch to traveling one? The answer is simple: it stops being pure standing wave at the moment when the amplitudes of the two oppositely-traveling components become different. Instead, you have a superposition of a traveling wave and a standing one.
Comment: +1 for the physicist's old trick of deducing general results from what happens in between special cases.
Comment: @DavidRicherby There is no continuous process that converts a standing wave to one moving at a fast speed travelling wave over an arbitrary short interval; there is a continuous process that converts a standing wave to a very slow travelling wave over an arbitrary short interval.  Basically, "slowly becomes moving" is continuous, while "instantly stops/starts" is not.
Comment: Hmm. I think this needs a bit more argument. You say that, obviously, the change-over is when the amplitudes become different. But what if the asker comes back and says that, obviously, the change-over is when the other amplitude becomes zero? Why does it have to be your endpoint, rather than the other one? I suppose your comment about it being a superposition kind of addresses this but it feels like you need a little more.
Comment: @Yakk That seems to fill the gap -- thanks.


Export VPN configurations from Android

Question: I would like to export all my VPN configurations stored in my smartphone to my pc. I use three VPN apps (VPN Master, USA VPN and Bettermet), in your opinion have I to find by myself all certificates and credentials or is there a place where I can find all this stuff stored in the system settings?
Answer: Different apps working with different VPN protocols have different methods of handling authentication credentials (username, password, certificate, key etc.). I didn't use any of three apps you mentioned, I guess those are all proprietary apps with purchased services (or at least under some T&C if you don't pay them money, they charge you some other way). If you have root you can check their data directories under /data/data/, but I don't think you would be able to extract any useful data from there. There would be encrypted files, though some (free) VPN apps save VPN configuration (e.g. .ovpn) files in plain text.
Some general purpose apps like OpenVPN Client - the one I use with my personal OpenVPN server on AWS EC2 - have a UI option to export VPN profiles as text files. But that won't be the case with purchased VPNs if they don't want you use the service on multiple devices or particularly on PC. You may ask them for a multi-device license / contract or go for some other option. https://www.vpngate.net, for instance, is a network of volunteers who offer a large collection of VPN configurations of multiple protocols that you can freely use on any number of devices.

Export VPN configurations from Android


Why is K9999 almost identical to Tetsuo Shima?

Question: I was watching this video which shows the similarities between both characters. I suppose it must be a kind of tribute, or maybe is just a vile copy (I don't think so). Anyone knows the reason?
Comment: It looks like footage from the movie spliced into video of the game. It's clearly not from the game itself.
Answer: Wikipedia says

and K9999 (pronounced K Four-Nine), a clone from Kyo entirely based on Tetsuo Shima from Akira, able to transform his arm into a long tentacle like Tetsuo's. Due to copyright issues, for the King of Fighters 2002 remake he was replaced with a similar character.

but gives no sources.
Answer: K9999 won't appear in any future games because

SNK hates the character
He is a liable lawsuit in which the creators of Akira could sue SNK Playmore
Elioth, a Korean company helped co-create King of Fighters 2001 and owns the rights to him
He was replaced in KoF 2002 Unlimited Match with a character called "nameless" who looks like Black Jack from the anime.
Answer: I think K9999 is the 9999th android of "K" because it disappeared, looking for the nests hideout and destroy it because they killed the original "K" who's real name is Kryzalid.
Tetsuo Shima is just a kid who grew up poor and turned into a mutant by Akira and put into an Akira Institute, and he escaped not knowing that his infected arm must be kept stable and that's why he ended up transformed into a huge mutated ugly monster and just died.


Excel chart by date

Question: I am trying to make a chart that represents our company's order forecast. I want the chart to be a pivot chart so that it automatically updates. I have a pretty in depth table that will be driving the chart, but the main two pieces of information that I will take from each record are quantity and ship date. What I want the table to display is the total number of pieces we are supposed to ship each week. Additionally the values that are charted will need to be filtered based on weather they have already shipped and what type of unit they are. A starting point would be hugely helpful, or if someone could just point me towards some resources that would be great too. Thanks.
Comment: pretty hard to do much with no idea how your pretty in depth table is structured
Answer: Start with learning the basics of Pivots in Excel, for that I would suggest:
PivotTable II: Filter PivotTable report data in Excel 2007
PivotTable III: Calculate data in PivotTable reports in Excel 2007
As well for calculating a week number from a date look at the WEEKNUM() function.

Excel chart by date


Are there any studies comparing different climate models on how well they've forecasted the climate in the past?

Question: E.g. IGCM, HadCM3, HadGEM1, GFDL CM, CGCM, CCSM, CFS, and ECHAM.
Comment: I think as it stands, this question is too broad.  There are **many** studies comparing climate models, either with each other or observations.  Many of those studies focus on particular topics.  For an overview, start with the IPCC AR5 WG1 report.
Comment: Agreed, the answer to this is "yes".
Answer: Yes. The biggest and broadest are the Palaeoclimate Modelling Intercomparison Projects (PMIP), which are the past-climate equivalent of the Climate Model Intercomparison Projects (CMIP).
The latest is PMIP3. It includes many of the same models that were used in CMIP5, as well as other models that are more focussed on representing past climates. The "overview" link on the PMIP3 page gives an indication of what the project covers, including experiments into the impacts of climate forcings, as well as benchmarking and comparison of models (e.g. quantitative and qualitative assessments of model performance over past climates).


How to transfer Mac Mail signatures between computers

Question: So, I need a way to transfer one Mac mail signature design to another computer. I don't know why this is so obtuse and hidden from users, but here's my issue. I'm using a Signature generator to produce our company's email signatures but we have users across most of the major platforms. Other mail clients seem to behave well, but pasting the signature generator's output in Mac Mail on Mojave fails, and the signature design is broken. All the mac's being targeted are running Mojave.
For my process here, I have 1) copied the generated signature, 2) opened preferences in Mail, 3) created a new signature, 4) unclicked the default font option, closed the preferences tab. When I add the signature to a message the design is changed to the point of unusability.
Alternatively, I have also tried the creating a placeholder signature method (by creating an empty signature with no default font, identifying the signature file in the library and the replacing the body tags and locking the file) as well as just copying over the signature files. Each method either produces bad results and it's unclear why (even worse changes to the design) or no results at all.
So...how do I easily copy and edit mail signatures for multiple users.
Answer: A theoretical solution...
I find my Mac Mail signatures are stored in the folder at ~/Library/Mail/V6/MailData/Signatures. You may be able to copy the contents of the folder at this location from one computer to another.

Hit ⇧⌘G (or Go > Go to Folder... in the Finder) and enter ~/Library/Mail/V6/MailData on the computer that has the signatures you wish to copy. Locate the "Signatures" folder, and copy it over to your target computer.
Then (on the target computer), navigate to the same ~/Library/Mail/V6/MailData location, replace the Signatures folder (if present) with the version you copied.
Open up Mail and check if the signatures are there.

Two warnings:

I haven't tested this, so it might not work/it might mess things up. Make sure you have a backup copy of the signatures folder from your target computer before overwriting it so you can revert if anything goes wrong.
If there are already custom signatures on the target computer, they will be overwritten.
Comment: That's what I want to avoid, I want to transfer one signature
Answer: Building on Michael Noguera's answer, I was able to transfer just one signature. Some file copying and maybe editing are required.
On the Mac where the signature already exists, look in ~/Library/Mail/V5/MailData/Signatures (yours may not be V5 but pick the most recent).
If the destination Mac has no signatures yet, just copy the entire file AllSignatures.plist. If the destination has some and you want to preserve them, you need to go into the file AllSignatures.plist, find the signature you want by looking at the SignatureName field. Copy that entire XML <dict> ... </dict> block to the destination Mac's AllSignatures.plist file (your destination Mac may have a different version path, i.e. V7, but that's ok).
Now you need to copy the signature itself. In that dict block, there is a field named SignatureUniqueID and the field after it is a long hex string. Look for a file in that directory with the same name as the hex string. Copy that to your destination Mac's Signatures folder.
Quit Mail and restart it. But you may not be quite done.
In my version of Mail (version 13.0), when I opened Preferences --> Signatures, I could see my copied signature in the All Signatures list but it was not associated with one of my mail accounts. I dragged the name of the signature from the middle column to the account name in the left column. Then, when I try to send a new mail from that account, it finally showed up in the possible signatures list.


Schematic and program listing of 28743?

Question: Looking for more info on circuit board of 28743. E.g. what is the processor used? Would like to be able to reprogram the chip. E.g. program the train to stop on the third STOP directive strip, or reverse the train direction if it immediately follows a TOOT directive strip. Ultimately I'd like to program it from Scratch or Python code, but that may be asking too much.
Answer: If the schematic you are asking is for the LegoDuplo, Train Push & Go Motor
with the circuit board that looks like:

This schematic is proprietary information that belongs to the Lego group.
This element uses a Bluetooth Low Energy radio and has an FCC ID: NPI28743
Perhaps you could create your own schematic and post it here.
Comment: I found what I wanted at 'https://pypi.org/project/bricknil/'.  This gives me the capability to do what I want.  Thanks
Comment: Thanks for the info.  I'll see how far I get tracing the surface mount components.
Comment: @F Gruhl, That's a great find! Good job

Schematic and program listing of 28743?


Upgrade from Drupal 7/ CiviCRM 4.6.38 to Drupal 9 / CiviCRM 5.37.2

Question: Good morning ladies and gentlemen,
I would like to upgrade my old installation of CiviCRM on an old system (Drupal 7, CiviCRM 4.6.38 ) to an up to date system like Drupal 9 / CiviCRM 5.37.2. Are there any suggestions how to do that including migration of all data? CSV export?  Mysql-dump (which tables?). I am very open minded (Wordpress instead?) and experienced hacking the shit out of my system. Just looking for a best practice solution.
Thanks for your help,
Robert
Answer: If you have a very simple d7 front end with minimum common modules than it won't be difficult to upgrade from d7 >> d8 >> d9.
To Upgrade Civi i would do incremental upgrade i.e

4.6 > 4.7(latest)
4.7 > 5.8(latest)
5.8 > 5.22(latest)
5.22 > 5.37(latest)

Would upgrade Civi first than drupal.


How many people has Jim killed in Under the Dome?

Question: How many people has Jim killed in Under the Dome? This is a serious question, as I'm starting to wonder if Jim is a greater threat to humanity than the dome and what's inside it.
Answer: From Wikia of the character Jim, he has killed 18 people directly and one indirectly. You can see it in the character detail in the side section.

Killed Victims: 18 killed
1 indirectly killed

You can also see the list of killed victims there.

Lester Coggins (pushed his head to the Dome; hearing aid exploded)
Boomer Platt (killed in an explosion of a propane tank)
Agatha Seagrave (caused; drowned)
Maxine Seagrave (shot once)
Otto Aguilar (shot once)
Dorothy "Dodee" Weaver (fatally shot in the chest)
Lyle Chumley (fatally stabbed in the chest)
Philip "Phil" Bushey (indirectly; jumped off a cliff after Big Jim closed the path to Zenith)
Rebecca Pine (bludgeoned to death)
Andrea Grinnell (fatally shot in the head)
Marston (throat slashed)
Carolyn Hill (unknowingly; crushed by falling debris)
Hektor Martin (shot in the head)
Kyle Lee (bludgeoned to death with a trophy)
James "Junior" Rennie (stabbed in the heart in self-defense)
3 unnamed Chester's Mill residents (1 man stabbed in the back and 2 men sliced in their necks)
2 unnamed farmers (both shot while fighting for the well on Ollie's side)


Update (not add) List Item with PowerShell

Question: I have managed to work a PS Script that added circa 9k items from a CSV file. After working some parsing issues with date/time, People fields etc. It's finally worked and all 9k items now sit on the SharePoint list, yaay.
I've just been approached, asking "can you fit in another column" with another 9k list-items, only this time it's just one column that needs adding/updating on the same list I just imported.
The concept that I can't understand is, I want to update the already created items, and not all of them either, just specific ones that fall within a range. What can I use as the anchor / unique identifier? I'm thinking item ID. What logic do I use to tell is to only update the ones that match the same ID number that's in the CSV file?
Thanks
Answer: If you saved the ItemId when you created the items it would be best to use that with SPList.GetItemById. If not you could use CAML or SPWeb.GetListItem. The latter is easier and I'd assume you would be able to easily determine the destination path based on your CSV.


How can I determine when colliders of two gameobjects touch one another?

Question: I stop gameobjects from colliding with one another by having box colliders around the gameobjects with dimensions bigger than the gameobjects. It works fine, but I want that when the gameobjects collide with one another, they stop moving. I cannot use OnTriggerEnter as I have turned IsTrigger off. Is there a thing which can determine when two gameobjects' collider touch each other?
Answer: OnCollisionEnter(Collision collision) fires when two colliders enter collision (similar to OnTriggerEnter but for non-trigger interactions), provided that the moving collider has a Rigidbody attached.
You can also use Physics.CheckBox / Physics.OverlapBox / Physics.OverlapBoxNonAlloc to scan for overlaps in a given prism of space, if you want to manage the physics yourself.


Satellite Images on OPeNDAP

Question: I am looking for global satellite images(as recent as possible - say three hours ago) of meteorological data that can be accessed through OPeNDAP protocol i.e. subsetting via latitude, longitude and time. Meteosat does have them but only upto 2015 - Meteosat OPeNDAP
I am looking for current global satellite images that can be accessed via OPeNDAP.
For continental USA this site does provide the images - CONUS
Answer: NASA's worldview app is pretty cool and might be a good starting place, but for OPenDAP access you probably want to look into one of NASA's DAACs. For example, the Physical Oceanography DAAC, PODAAC has an OPeNDAP server located here.
Comment: I checked the site but the images available via OPeNDAP are not current. But still a good site and happily upvoted
Comment: I'm not sure about OPeNDAP, but [NASA's LANCE](https://earthdata.nasa.gov/earth-observation-data/near-real-time/download-nrt-data) website may have something helpful if your priority is getting the data as fast as possible.
Comment: great site for current satellite images. I will send them a note asking them to put their images on OPeNDAP. The reason I want this is because I want to invoke OPeNDAP via Python and link it to the rest of my application

Satellite Images on OPeNDAP


postgres_fdw and postgres version upgrade

Question: Case explained
I'm facing difficulties concerning performance of queries using a Postgres 9.5.4 database set up on a different server connecting via Foreign Data Wrapper to another instance of Postgres 9.5.4.
I've already tried enabling use_remote_estimate setting via ALTER SERVER but this seems not to fix it as much as I thought it would.
Regular queries with joins tend to take >3X longer when issued via FDW database.
I've investigated data transfers, gave more RAM and CPU to utilize on FDW but with no success. Anyway it seems like it's not even using that much resources.
Possible improvement
I've read about join and aggregate pushdowns for FDW introduced in Postgres 9.6 which seems great and should improve response time, but I'm unsure whether or not it's enough to just upgrade the FDW Postgres server. Do I need to upgrade the main server I'm connecting to as well?
Example
Simple example of a query that I think could benefit a lot from upgrading Postgres to 9.6 would be:
<code>db=# EXPLAIN VERBOSE select max(add_date) from mytable;
                                        QUERY PLAN
-------------------------------------------------------------------------------------------
 Aggregate  (cost=2084783.99..2084784.00 rows=1 width=8)
   Output: max(add_date)
   ->  Foreign Scan on public.mytable  (cost=100.00..1963010.07 rows=48709569 width=8)
         Output: id, id_a, id_b, id_c, allowed, mod_date, add_date, idv
         Remote SQL: SELECT add_date FROM public.mytable
</code>
There is no index, and won't be, on production, but it takes around 10s to complete on master server (50M rows), while on FDW server it goes as high as 250s, which I believe is due to the fact that remote SQL executed is sending all the data to the server in order to allow it to aggregate.
Back to question
Again, to benefit from what 9.6 has to offer do I only need to upgrade Postgres instance on server that has the FDW Server and foreign tables, or also the master server?
Comment: I've tested it and seems that upgrading server that uses FDW mechanism to Postgres 9.6 does not apply aggregation pushdown.
Answer: Join and aggregate pushdowns are supposed to go live on Postgres 10, not Postgres 9.6 which is why remote queries are not being sent the way I expected it to.