How to keep sticky notes from falling down?

Question: I love sticky notes. I have them on my wall, on my desk, on my face, etc. However, if a breeze occurs or time passes, they fall down. I've tried using a piece of clear tape, which works, but is inconvenient. What can I do (without using tape or harming the surface on which I stick them) to keep them from falling down?
Comment: Good question.  I haven't found any solution other than removable tape. (Which is why this is a comment.) :-)
Comment: Replace them after unsticking them a few times? ....they don't last so long when you unstick them and restick them a number of times.
Comment: None of your reasons make sense people or nor do they work. Please think of something that well help because i really need help with my sticky notes. Pleaseeeee!!!!!!!
Answer: Your notes are probably falling down because you separate the note you need from another note incorrectly, i.e. by pulling from the end of sticky note. Therefore sticky edge bends and the note pulls itself from the surface you stuck it to.
Instead try separating it from another by pulling it off from the right or left, and try not to bend it.
To elucidate this refer to the following visual:

original image
Comment: That can't be it, because I peel mine from the side and I have the same problem.
Comment: @starsplusplus, if you're taking the sticky note off the pad correctly, then it is likely due to a dirty/dusty surface. Make sure you clean the area you plan to put the note prior to affixing it.
Comment: I think they're just not sticky enough to remain stuck to vertical surfaces. If I trim the non-sticky part (making them lighter) they last a bit longer.
Answer: Here are some tips:

Never touch the sticky portion. This wears away at the sticky material and can make it less prone to sticking.
Clean the area you want to adhere it to. If the area you adhere it to is all dirty the note won't adhere properly.

Here are some methods to make them stick:

Use glue. If you use a glue stick that is water soluble that should make it stick to objects and not leave a mark.
Take a piece of tape and fold it over so that it is double sided and use that. This method may leave a mark depending on the tape.

Invest in stickier sticky notes, possibly.
Check out LifeHacker. com
Answer: I can't believe that nobody has posted this yet...
First, one thing I've been told is to not pull sticky notes upwards or sideways. Doing so causes them to bend, which allows grime to get between the sticky surface and whatever surface it's attached to. That obviously reduces its ability to stick to a surface.
Instead, prepare the note (write or draw whatever you want on it) first, then lift it slightly from the bottom (the edge opposite to the sticky edge), place a finger underneath it to hold the remaining ones in place, and pull straight toward you. Place it flat against the surface you want it to adhere to (after cleaning the surface, if necessary), and gently flatten it against the surface.
If that is not sufficient, while this latter is admittedly not a life hack, you should consider purchasing "super-sticky" sticky notes.
Comment: Thanks, only your solution worked for me.
Answer: Apart from all the methods mentioned above, wiping the surface you are sticking your notes on may increase the time the note stays there


Does Enterprise Search Center have anything to do with Content Search Results web part?

Question: I've been wondering what Enterprise Search Center has to do with (if anything) Content Search Results web part and/or Content Search web part. Do I need Enterprise Search Center for the queries to work in Content Search Results web parts?
Answer: Their is no relation between Enterprise Search Center & Search Web Parts. Only requirement for the Search Web Parts are, You have to Configure the enterprise Search Services Application.

Web Parts that use search technology to show content in a publishing
  environment (referred to in this article as Search Web Parts) show
  content that was crawled and added to the search index, These Web
  Parts have queries defined in them, and when users browse to a page
  that contains a Web Part that uses search technology, the Web Part
  issues the query automatically. The query result is then displayed in
  the Web Part. You can modify the query in the search Web Part to fit
  your content needs.

Please check this for more info: http://technet.microsoft.com/en-us/library/jj679900(v=office.15).aspx
http://www.sharepoint-journey.com/search-results-and-content-search-webparts-sharepoint-2013.html


Moisture of the product

Question: I noticed that after some time the gummy bears are really sticky after eating one of the packets of gummy bears and having them glued to my hands. Where does that moisture comes from and what is the cause? What changes can be implemented in the recipe to avoid higher humidity in the final product?
Comment: You did not mention there is a sugar/acid coating. That changes things a bit. See linked question http://cooking.stackexchange.com/questions/60302/making-super-sour-sweets-issues-with-stickiness/60414#60414
Answer: Its likely that :

(1)the packet you ate had a small hole in it
(2) before the product was packet the manufacturer made the mistake
of leaving the product in a humid area before packing.
Most candy needs to be properly sealed, just because of the same reason you are pointing out that you experienced. Remember gummy bears are made of sugar and all sugar has moisture in. And sugar attracts moisture. Not sealing the product would allow the candy to attract the moisture that is in the air all around us. Some areas more than others if course.

As for how the manufacturer could improve this from not happening:

(1) Having the correct balance of ingredients is a must
(2) Cooking to the correct temperature see link see link on the
different temperatures and results.
http://whatscookingamerica.net/Candy/candytemp.htm
(3)    Producing/Packing in a low humid environment
(4) Sealing the    product properly in bag.
Comment: thanks for your respond. The problem is that the 2,3,4th point are carefully carried and these points can be easly excluded. The problems lies in the recipe- and mostly with the product coated wit sugar/acid mixture. The question is if maybe changing proportion of its or replacing the ingredients with others could prolong the shel-time( the same time lead to lower moisture)

Moisture of the product


How to fit kitchen cabinets to corners that are not 90 degrees

Question: I'm currently designing a replacement kitchen for my house. The kitchen is U shaped so going across three walls of the house. The middle wall is not 90 degrees to the other two, it is more like 105 degrees to one wall and 75 degrees to the other. How do you usually fit kitchen cabinets to these corners? What are different ways this can be done?
Comment: Is "rebuild the kitchen" an answer you could consider?
Comment: Can you supply more dimensions / measurements? How long are the legs, what are the angles?
Answer: Not all corner cabinets make up both sides of a corner. You can get a cabinet for example that is 42" long but with only a 18" door. Another standard cabinet will butt against it to form a corner. Normally a 3" spacer is used to make clearance for drawers and doors to open.  You may need more on your smaller angled corner. I believe they're called blind corner cabinets.  They normally leave an hard to access space but slide outs like in the picture below will help.
Answer: Well if the walls are down I would use this time to get the middle wall at 90 degrees.  You might lose a couple inches of space but your kitchen will look a lot nicer.  It's not just the cabinets but you will have to deal with countertops and other issues too.  We shim out things if you aren't right at 90 but you are a bit off to do that.
Answer: You could built a custom corner cabinet. alternatively, don't place a corner cabinet, but rather let the cabinets meet at the corner on their outside corners. Then just cover the gap with counter.
Note that the 75 degree wall might cause issues with drawers and doors in the corner. You may want to rethink wrapping cabinets around that particular corner.
Answer: The simplest solution — if possible — would be to not use the bottom of the U, but only the legs. You haven't supplied any dimensions, so I have no idea if this is possible, but that would leave you without any corner cabinets to be fitted.
Depending on what you want for your kitchen, you could either leave the bottom completely empty, or use it for something special, such as a free-standing stove or a fridge.


Is 1% m/m the same as 1% w/w?

Question: Hydrocortisone cream seems to be sold as 1% w/w, but my cream is 1% m/m, which is confusing. Are they the same units or the same concentrations?
Answer: "[M]ass is the amount of "matter" in an object (though "matter" may be difficult to define), whereas weight is the force exerted on an object by gravity." (Wikipedia quoting [de Silva, G.M.S. (2002), Basic Metrology for ISO 9000 Certification, Butterworth-Heinemann, 214p.]
Well-known relationship:
$$
W = m \times g
$$
where W is weight, m is mass and g is the acceleration of gravity.
Because g is a constant that cancels out in a ratio, mass/mass and weight/weight are identical.
Likewise, the ratios % m/m and % W/W are identical.
Comment: Indeed m/m would be more appropriate. Thumb up for the pharmacists.
Comment: Let's be thankful the % units were labeled at all!
Answer: The symbol "w/w" is more often used in chemistry, whereas its equivalent "m/m" is favored in pharmaceutical industry.
For instance, European Pharmacopoeia in section 1.2. Other provisions applying to general
chapters and monographs suggests the following methods for expressing concentration [1, pp. 4–5]:

Expression of content. In defining content, the expression 'per cent' is used according to circumstances with one of 2 meanings:
– per cent m/m (percentage, mass in mass) expresses the number of grams of substance in 100 g of final product;
– per cent V/V (percentage, volume in volume) expresses the number of millilitres of substance in 100 mL of final product.
The expression 'parts per million' (or ppm) refers to mass in mass, unless otherwise specified.

Please note, however, that this is a somewhat flawed definition: neither of physical quantities such as "mass" or "volume" should be called or referred to as to "number
of grams" or "number of millilitres", respectively.
Also, neither "w/w", "V/V" nor "m/m" — despite their widespread usage — are considered correct by the BIPM [2, p. 149]:

5.4.2 Quantity symbols and unit symbols
Unit symbols must not be used to provide specific information about the quantity and should never be the sole source of information on the quantity.
Units are never qualified by further information about the nature of the quantity; any extra information on the nature of the quantity should be attached to the quantity symbol and not to the unit symbol.
For example:
The maximum electric potential difference is $U_\mathrm{max} = \pu{1000 V}$ but not $U = \pu{1000 V_\mathrm{max}}.$
The mass fraction of copper in the sample of silicon is $w(\ce{Cu}) = \pu{1.3E−6}$
but not $\pu{1.3E−6 w/w}.$

Considering the aforementioned guidelines, the hydrocortisone (HCT) content should ideally be depicted as $w(\text{HCT}) = 1\,\%$ to avoid ambiguity.
References

Council of Europe; European Directorate for the Quality of Medicines & Healthcare. European Pharmacopoeia, 10th ed.; Council of Europe: Strasbourg, 2019. ISBN 978-92-871-8912-7.
BIPM. Le Système International d'unitès / The International System of Units ("The SI Brochure"), 9th ed.; Bureau international des poids et mesures: Sèvres, 2019. (PDF)

Is 1% m/m the same as 1% w/w?


I have a dead Toyota Prius

Question: 2007 Toyota Prius blown engine need to put in neutral to move but can't turn on. Does anyone know how to put in neutral?
Answer: Is the battery fine? Charge the 12V battery, which should be in the trunk, but there should be jumper / charging connections under the hood.
Toyota uses a shift-by-wire functionality, so putting to neutral requires 12V battery to supply current to the electrical systems.
Note also that the transmission (a planetary gearbox with 3 shafts) and both of the 2 electric motors (which are located in the transmission) are continuously connected to the wheels. In fact, even the internal combustion engine (ICE) is continuously connected to the wheels and can't be disconnected, but the electric motors should spin free if in neutral, meaning the ICE shouldn't rotate if you push the car.
Are you sure it's just engine damage? Not transmission damage? Or parking mechanism damage? Because if the transmission or parking mechanism is damaged, you may be unable to push the car in neutral.
Edit: some basics on how a Prius transmission works:
There is a planetary gearbox with 3 shafts:

Shaft #1 is connected to the wheels and motor-generator 2
Shaft #2 is connected to the internal combustion engine (ICE)
Shaft #3 is connected to motor-generator 1

If you push the car with ICE turned off, shaft #1 rotates in the direction of pushing the car. Shaft #2 is held still by the ICE. Shaft #3 rotates backwards, caused by shaft #2 being held still by ICE.
There is a relationship between the rotational speeds of shaft #1, shaft #2 and shaft #3, but basically there's two degrees of freedom, the relationship removing the third degree of freedom. So, if you have an additional constraint that shaft #2 is being held still, this removes an additional degree of freedom, so the remaining count of degrees of freedom is 1. This degree of freedom is basically the movement of the car forwards / backwards, and at the same time, MG1 rotates in the opposite direction.
There is no clutch in a Prius. The engine is continuously connected to the wheels, but the three shafts give an additional degree of freedom which allows electric CVT (e-CVT) transmission to work. The additional degree of freedom also allows the "neutral" gear to work.
Here's a Flash widget that explains how the power split device (the planetary gearbox) works: http://eahart.com/prius/psd/ ...but unfortunately, it requires Adobe Flash which is not the most secure plug-in out there.
Comment: you state the ICE is continuously connected to the rear wheels, so how do you expect the ICE not to rotate when you push the car? Are you taking the wheels off the ground?
Comment: @SolarMike There's now more information -- it's connected to the FRONT wheels, via a three-shaft planetary gearbox with 1 additional degree of freedom if ICE is being held still, so you can have the neutral gear.
Comment: So, it is now correctly explained , ok.
Comment: Great answer and info.  +1

I have a dead Toyota Prius


How to install mdwtools package with MiKTeX?

Question: I followed the instruction from CTAN: http://docs.miktex.org/faq/packages.html, then I ran the command:
mpm --verbose --install mdwtools.
The system said the package was installed successfully, but I couldn't find mdwtools folder under my C:\Program Files (x86)\MiKTeX 2.9\tex\latex directory. Does this package require a special installation? I'm current using TexMaker on Windows 7. Most of the time, I just include the line: \usepackage{X}, and TexMaker will automatically install the package. However, with mdwtools, nothing happened! So what can I do in this case? Thank you.
Comment: I don't use MikTeX, but I suspect that the problem might be connected with the fact that you can install it as a user and as an admin; if you install a package then with wrong privileges, things might go wrong (I suppose).
Comment: @mbork: Thanks a lot for your quick reply. However, I ran it as administrator though, and TexMaker keeps telling me it couldn't find the .sty file.
Answer: mdwtools is not a single sty but a bundle of packages. To trigger the automatic on-the-fly installation you would have to use one of this packages in your document e.g. \usepackage{mdwtab}.
You installed the package in user mode so it should now be in one of the miktex trees in your user profile. Probably in the one called UserConfig or UserInstall. Look up the path in miktex settings (user mode).
It could be that the mpm command didn't update the  FNDB so run either initexmf -u on the command line, or use miktex settings (user mode).


What can I build with Raspberry Pi 2011.12 with minimum equipment?

Question:
Abandoned post by Unregistered user.

I am new to all of this and I managed to get a Raspberry Pi 2011.12. Since I have not attempted to build anything before, I am already hitting a wall. I have tried looking things up on the web, but it suggests to buy a lot of things. I understand it is unlikely that you have all the products yourself, but I would like to utilise what I already have and perhaps use that to build something later on again. Currently, I have an old Dell PC and the Raspberry circuit itself. Any suggestions are much appreciated. I am excited to know what my first project could be. Thanks a ton.
Comment: Seems too broad a question for this site.  Look through issues of the [MagPi](https://www.raspberrypi.org/magpi/) for ideas.
Comment: abandoned question by unregistered user
Comment: As thlhngan says, if you don't have any parts then you can't add anything *physical* to the pi.   Other than perhaps a 5V fan (whoopee...) and buzzer, in this context there's not much of use value in the old PC.  The buzzer will probably emit a fixed pitch when voltage is applied, but if it requires 5 then you can't turn it on and off (will definitely apply to the fan as well).   You might be able to salvage some buttons and LEDs from the case.  Unfortunately the latter require resistors to use (you can exploit the Pi's internal resistors for the former, but make sure you understand it first).
Answer: You can't build much without the proper building blocks :)
However, the Pi is a good platform to learn programming, especially Python and C. One thing you could build would be something to do with networking. For example, there are utilities (nmap is one of them) that allow you to discover other devices on your network, with their IP, their MAC address and their hostname. You could write a script that periodically checks for new devices on the network (or devices that leave the network, or both) and send you an email about it. This is useful to determine if and when a device stops responding and may need a reboot.
Answer: There are one or two things you might play about with using minimal hardware.
Kodi is one of the most popular media centre programs out there. It plays pretty much everything, and it has a fairly huge array of community built add-ons that allow streaming of radio, TV and movies. OpenELEC is a variant of Kodi which has been somewhat optimised for tiny computers like Raspberry Pis. I've run a copy of OpenELEC from a Pi 2 hooked up to my main TV for the last few years, and it's great. They have a decent write-up on the setup/installation process on their wiki page here.
Makezine have a good tutorial on turning your Pi into a short range FM transmitter here. The sum total of the equipment required is a length of wire that you can connect (you might get away with wrapping a pin if you don't have a soldering iron or pin headers) to a GPIO pin. Make have provided a pre-built image file accompanying the tutorial, which contains a modified version of the venerable PiFM application by Oliver Mattos and Oskar Weigl. If you can get this project up and running you should be able to transmit audio from your Pi via the antenna to any nearby FM radios.
Answer: Make a web blocker with Pi Hole which required nothing but internet and it will block all adds in your house


Why do people talk (or communicate)?

Question: I think that people talk for planning immediate benefits or planning future benefits. For example if someone wants to eat a fruit on a tree but he doesn't know how to get it so he asks someone to get it for him so he talks. So do you think that these are the correct reasons why people talk?
Comment: what kind of answer would satisfy the question "why"?  what would qualify as sufficient explanation?  would one have to be able to explain every single utterance in terms of this answer?  is this an evolutionary question?
Comment: @honi No, a sufficient explanation would include some very basic reasons
Comment: what does that mean?  you have to be much more clear.
Answer: We evolved from animals which live in groups. Social animals such as chimpanzees (our closest relatives) communicate to one another to warn of danger, call for help, express emotions, etc. In a broader sense, there are advantages to living in groups: Mutual defense, stronger attacks on prey, ability to share resources...
https://en.wikipedia.org/wiki/Evolution_of_human_intelligence#Social_brain_hypothesis
https://en.wikipedia.org/wiki/Sociobiology
Answer: From psycholinguistic point of view, communication helps to understand others behaviour better even in a non-verbal way, economic basis of communication is the fact that humans are wanting beings who need things from food to luxuries and therefore need to communicate, evolutionarily, I would suppose communication help to adapt more to our environment. Consider your own self when you are sick and need to talk to those around or a doctor, without communication, would that be possible? You may want more about the usefulness of communication, see a brief summary here http://geniuslight.blogspot.com.ng/2015/11/psycholinguistics.html

Why do people talk (or communicate)?


How is ASIC design different from FPGA design? Do you write HDL (Verilog, VHDL) to design and ASIC the same way you would for an FPGA?

Question: From my limited understanding i feel as though one could just take the synthesis output from Verilog/VHDL code and then use that design to fabricate on silicon the sea of gates.
Comment: ASICs have been around ever since we have been making IC's.  FPGA have been around since the 80's.  During the past 20 to 30 years, the design tools for both have merged and many use VHDL for either.  Why use an FPGAs?  Reprogramming, quick to market, economical for low volume projects.  Why use ASICs?  Lower cost for high volume projects.
Comment: An FPGA is technically an ASIC, in that its entire fabric is adaptable to a specific application.
Comment: yeah but the FPGA is not an ASIC that someone designs for an ASIC's purpose besides being an FPGA
Comment: @MattYoung And some would say as an FPGA is quite a generic device (it can be used for many applications) that would mean it is **not** an ASIC. The definition of ASIC is quite vague. I'd call the chips I work on ASICs as these are chips for Radar which is quite specific. At the opposite end an opamp or a chip with logic gates is not an ASIC as it can be used almost anywhere. Anything in the middle depends on your definition of what is an ASIC.
Answer: 1) not all ASICs are digital-only. Some have analog circuits as well or are even analog-only.
So your question only applies to digital-only ASICs or only the digital part of an mixed-signal ASIC.
Yes in theory you would think that you could:
1) Write your VHDL
2) Generate the netlist (this describes the actual circuit)
3) Implement that netlist on either FPGA or an ASIC.
But in the real world it is not that simple.
Step 1 is indeed the same but the netlist for an FPGA will be different.
On an FPGA you will only have the gates available which are implemented on that FPGA.
On an ASIC you can choose any gate and as many as you like from the library describing the ASIC's manufacturing process.
This difference means different optimizations might need to be made to either design. For high-speed design it is essential to simulate the netlist so that actual delays are included. This will reveal timing issues that have to be fixed.
So yes, the starting piont (VHDL, Verilog) could be the same but that does not mean you can "blindly" put it on an ASIC or FPGA and expect good results.
What is done in the real world is that first the VHDL or Verilog is evaluated on an FPGA for proper functionality. Then that debugged code is used to make an ASIC. Even then many simulations have to be done to ensure proper functionality.
Comment: *So in the real world people that design ASICs to start out with FPGAs* Not always, it depends on how mature a design is and/or how well it can be simulated and/or how much the designers think testing their design on an FPGA is needed.
Comment: Thanks! So in the real world people that design ASICs to start out with FPGAs (and supporting analog circuitry as well? Though i doubt an FPAA is used).
Answer: FPGAs and ASICs have differences e.g. in the reset and initial value behavior. Here is a not complete list. The list could be more specific if you tell us your FPGA vedor and/or the used ASIC library.
FPGAs:

general

have an power-on reset
have an JTAG/debugging interface

Flip Flops

have asynchronous and synchronous resets
have clock enables
have a low or high active reset
have an init value

RAMs

have dedicated RAM blocks with fixed sizes
have an init value

DSPs

have arithmetic units for multiplications and addition with fixed sizes

ASICs:

general

power-on reset needs to be implemented
JTAG/debugging needs to be implemented

Flip Flops

reset, clock enable, ... depends on the primitive library
have no init value

RAMs

are generated by macros

DSPs

multipliers are generated by macros
multiple macros and primitives need to be combined to get the features of a DSP cell
Answer: An FPGA is nothing more than a RAM-based ASIC.  While HDL is "portable" from one target to the next, you must always keep in mind what those target libraries offer.
If you prototype an (eventual) ASIC design in an FPGA, you should never use any Hard Macros that the FPGA offers that don't have an "equivalent" in the ASIC library (e.g. IO Tap delays may not be available in your ASIC library whereas they are in Xilinx).  Your FPGA should have very distinct boundaries ("Black Box" capabilities) for clocks and resets, memories, and an IO ring, that you can easily swap out when targeting the ASIC.
Typically though, your HDL should translate easily FPGA to ASIC.  I highly recommend drawing your design in a program like Visio to show gates, FFs, FSMs, etc. before writing anything.  And to help ensure you get what you planned, try not to get "fancy" with your RTL... IMO, being explicit as possible is good practice, even if it does take a few more lines of code.
Comment: Some FPGA's do not have RAM and are fused
Comment: ^truth...  but, in-general, conceptually, and to help alleviate the misnomer that an FPGA consists of "firmware", I prefer to present it as such to help place focus back on the digital IC design and not the target.  But, I do appreciate your comment for accuracy-sake.
Comment: Also, some have ROM's (like altera max10, has two sections for two separate configurations) that you can load multiple "firmwares" on the same device's RAM


Splitting text into editable sections

Question:
I'm looking to create a similar text-effect as is in the picture. Ideally, the text could be "split" into different sections which could be colored to do shading of sorts. If possible, I would like to keep it symmetrical and neat.
Thanks.
Comment: There's no simple way to do it other than making vector drawings as shown in in [this tutorial](https://www.youtube.com/watch?v=bin9TZCbRzs)
Answer: This could be achieved by using multi colour fonts which are now supported in Illustrator CC.
This is an example below created using a free (for personal use*) colour font called Letter Board provided by fonts.lol, which I installed, typed some text, and then converted to outlines for recolouring.
Interestingly you can also colour the font to your own custom colour palette before you download it and then install, so you don't even need to recolour it in Illustrator at all.

I also found a more similar font to your example here on Creative Market which isn't free, so I can't test it.
*Note: A commercial licence is also available
I have no connection/affiliation with the fonts.lol or creativemarket.com websites.
Answer: If you want to start something which seems to be simple, you can try this:

It needs a simple font which contains only equally wide straight or circular lines and where two lines meet, they are either parallel or perpendicular. It doesn't work if there's usual V or N with sharp corner angles, they must have circular arcs instead of sharp corners, only 90 degree corners are allowed.
I haven't such font, so I drew one letter. In the left there's my drawn J. It got 8mm wide grey stroke, the parts are expanded and united to to a single strokeless closed shape, there's no stroke!
3D effect Extrude&Bevel is applied. There's only wireframe shading and 4 mm bevel
The extrusion result is expanded(=Object > Expand Appearance). The result seems to be ready to get filled with colors.
It isn't. It's a mess.
It needed releasing a clipping mask and three ungroupings. There were so many overlapping curves that I ended to select one black curve, then to select the same stroke color and press DEL. The released strokeless clipping masks were left.
I selected the remainders, filled the areas with the shape builder and gave some arbitary colors. The result is in the right.

Splitting text into editable sections


How to program a website to accept Ethereum payments

Question: Assume I have a site and I want to give unique address to each of my users that generated by an HD wallet.
If each user, send a little amount to his/her address,that it was less than transaction fee, unlike Bitcoin, I can't spend them, by generate a transaction with multi input, I think it's so bad.
On the other hand, each contract has only one address, so I can't have a contract with multi address to give each address to each user. What is the best solution in Ethereum world?
Answer: Instead of deterministic payment addresses, you might want to use a smart contract for the payment.

There is only a single smart contract (address) where the payments go in (you can also deploy multiple contracts e.g. one per store, but this is a different question)
Each payment comes with a reference message in the Data field
Smart contract can automatically reject too small payments

I believe this is how Coinbase payment solution for Ethereum does it as well.
Here is an example Solidity smart contract that is close to your problem. It is a payment forwarder, so it checks that the reference message in each payment is correct:
https://github.com/TokenMarketNet/smart-contracts/blob/master/contracts/PaymentForwarder.sol#L74
Also, the user do not need to manually type in the reference messages like in wire transfers, because Ethereum interaction happens with a web3.js wallet like MetaMask and the website automatically fills the information for the user.
Comment: Thanks. So if we have a transaction from a wallet or a system that doesn't automatically fill any information, we can't know which one of our user sent amount to our contract right?
I think I have to define a minimum amount for receiving, generate address with HD wallet, and finally send all of them to a main account. is this good idea? I know I lost some fee but it's safe to detect deposits.


Add fields to a coded block and use them in a templated block

Question: I want to programmatically create a block to which I can add a body field, a link and an image and then create a block twig template file where I can use these fields. For the uploaded image ideally I would want to be able to use a responsive image style. Am hoping someone someone can tell me how I would do this?
Comment: Why not use the field ui and the preinstalled image field type? And what do you mean by programmatically, you can do all things from the field ui in code as well.
Comment: I suppose I just want a one off custom block and don't necessarily want it to be a replicable thing. I have quite a few use cases where this would make more sense. Also it is better for pushing up the code using versioning
Comment: Yes, there are pro and cons, but the biggest pro is IMHO the image handling of the field ui, which is hard to implement in own code. If you don't want to clutter the block system with a lot of custom block types it could make sense to create a custom entity type (Console generates a twig template for it automatically) and then use a simple block plugin to place the entity including the template in a custom block..
Comment: Nice one thank you, that indeed makes a lot of sense, I shall give that a go
Comment: Hi @4k4 Sorry I have tried to create an entity and bundles but I never am able to create something complete? What commands do I use to create an entity and bundle so that I can add fields to it?
Answer: Probably the easiest way to do this is a block with a settings form.
When you place a block of this class via the block layout, you can add your information in the settings.  To have another block with different settings, just place another block.
Some sample code:
<code> public function blockForm($form, FormStateInterface $form_state) {
    $form = parent::blockForm($form, $form_state);

    $config = $this->getConfiguration();

    $form['my_block_text'] = array(
      '#type' => 'textfield',
      '#title' => $this->t('Foo'),
      '#description' => $this->t('my desc'),
      '#default_value' => isset($config['my_block_text']) ? $config['my_block_text'] : '',
    );
    return $form;
  }
  /**
   * {@inheritdoc}
   */
  public function blockSubmit($form, FormStateInterface $form_state) {
    parent::blockSubmit($form, $form_state);
    $values = $form_state->getValues();
    $this->configuration['my_block_text'] = $values['my_block_text'];
  }
  public function build() {
    $config = $this->getConfiguration();
    $text = $config['my_block_text'];
    ...
  $block = [
   '#theme' => 'my_module_my_theme',
    '#my_text' => $text,
    ...
  ];
  return $block;
}
</code>
For images / files, you can just use the standard file form type.  The config will get the fid of the image.  In the build, you will need to load the file entity and generate the URL to the file.  (Lots of existing examples of this).
To get it all to twig, you will need to use a hook_template() implementation that defines the twig template and variables. Then pass it to the theme using the render array created in the block build code.
Comment: Thanks, I think I have got this far but I would like to be able to add an image field to the block and then to print a responsive image style version of this in a block.html.twig file
Comment: Edited answer to reflect this.


Can a US official be charged and tried in court without first being impeached?

Question: For example, could Bill Clinton have been charged with perjury in the standard judicial system, even while sitting President? Or is impeachment and removal a prerequisite for judicial proceedings?
Comment: Bill Clinton was charged with Perjury to an in-house sworn hearing - that is why it went through the in-house judicial system of impeachment. Had he perjured himself in a normal courthouse then the normal criminal process would have been in effect. A normal criminal court charge MAY be the result following an impeachment process, depending on the cause (bribery, influence peddling, etc) but not necessarily. Similarly, a President may pardon a resulting criminal conviction, but not an impeachment. It is two separate judicial processes.
Comment: Perhaps it would help to clarify what you mean when you say "US official".
Comment: @MichaelBroughton Do I understand you to mean that a President can pardon himself (if criminally convicted)?
Comment: @WS2 - frankly, given how Nixon was preemptively pardoned, it may be technically possible (Not sure on that one), but for crimes in office criminal charges cannot proceed until the President has either resigned or been impeached and tossed. I don't see anything in the rules specifically against it, but I'd like to see the person with the cojones to try!
Answer: Governor Rod Blagojevich was charged and released on bail prior to being impeached and things going to trial. Holding office does not grant immunity,  nor does impeachment automatically imply removal from office, and neither are a prerequisite for criminal proceedings to be undertaken.
Governor Evan Meecham of Arizona, for example, was not even impeached until after his conviction.
Here's a short set of details on several gubernatorial impeachments
Comment: There's one exception to this - Congresspeople while they're doing things related to their job.  `They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place.`  Other than that, you're entirely right that being arrested is unrelated to holding office or being impeached.
Comment: Neither Governors Blagojevich nor Meechamwas were a US official.
Comment: "Impeachment is for breach of internal rules." Impeachment is specifically _not_ for breach of internal rules at the federal level, but for criminal offenses. `The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other High crimes and Misdemeanors.` - [U.S. Constitution Article 2, Section 4](https://www.law.cornell.edu/constitution/articleii#section4)
Comment: Yes, internal matters are separate, and criminal charges may follow impeachment if appropriate.
Comment: They were not Federal officials, no. And the impeachment rules differe from state to state according to their constitutions. The general rules, however, still apply. Impeachment is for breach of internal rules, and they may also result in criminal charges. Criminal charges for actions outside of official capacity, however, is not shielded at any level of government.
Answer: Article I, Section 6, Clause 1 of the United States Constitution says

"The Senators and Representatives [...] shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place.

This prevents them from most cases of criminal liability for things they do during debate and prevents them from being arrested during debate or while traveling there, but doesn't offer them any protection outside.
No such rights apply to the president. In fact, Article II section 4 of the US constitution explicitly states that: "The President, Vice President and all civil officers of the United States, shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors.". If an impeachment would be a prerequisite for conviction, this section would be redundant. If "perjury" is a "high crime or misdemeanor" warranting an automatic impeachment would be for a court to decide. There is no precedent for this, because no president or vice-president was ever impeached for criminal activity (Nixon resigned voluntarily).
This is different from many other democracies where it is common that parliament members have immunity from criminal prosecution unless the parliament revokes that immunity with a majority vote (which they usually do when there is reasonable ground for suspicion). The reason for parliamentary immunity is that the executives in some "less democratic democracies" like to abuse their authority over the law enforcement system to arrest parliament members who make uncomfortable voting decisions.
Comment: Clinton was impeached for criminal activity; he was just not *convicted* afterwards.  (Impeachment is the process of bringing formal charges against an official, not of removing the official from office.)
Comment: The conviction referred to by Article II, Section 4 is conviction by the Senate on articles of impeachment (see [Article I, Section 3](https://www.law.cornell.edu/constitution/articlei#section3),) not conviction in a criminal court. They are two completely separate processes.
Comment: "*If an impeachment would be a prerequisite for conviction, this section would be redundant.*" You mean if it were *already* a prerequisite. It's certainly reasonable to read that section as making impeachment a prerequisite for conviction by making a conviction without an impeachment ineffective.
Comment: Since there is no restriction on who a President may pardon, a President who was charged with a crime while in office could simply pardon himself, thus shielding himself from criminal prosecution as long as he was in office.  Impeachment serves as a check against that, since a pardon doesn't shield against impeachment.
Answer: A US official can be charged and tried in court without going through the impeachment process at all.

Consider Scooter Libby.  He was a US official.  He was indicted on multiple counts.  He resigned.  He was convicted.  His prison sentence was commuted but his conviction remains and he still has to pay several hundred thousand dollars in fines.
Consider Richard Nixon.  He was a US official.  He was pre-emptively pardoned.  He likely would have been charged and convicted for multiple felonies without going through the impeachment process.
Comment: @MichaelBroughton "The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors." Doesn't "civil officer" cover virtually all federal employees (except for military).
Comment: Scooter Libby, as neither an elected official or judge, would never have been impeached as that process is not applicable to him. Articles of Impeachment against Nixon WERE drawn up but became moot when he resigned before they could be voted on, thus ending that process, and which is irrelevant to the preemptive pardon he received to shield him from criminal prosecution.
Comment: It's a murky area, but only members of the executive branch or judiciary may be included - not all civil servants: http://law.justia.com/constitution/us/article-2/50-persons-subject-to-impeachment.html
Comment: But as it is a murky area, I conceed that, had Bush tried to shelter Libby, the Congress may have looked to impeachment to get to him - at which point the Supreme Court may have had to decide if he was impeachable. Gotta love institutions set up by lawyers to police themselves - they're ALWAYS an open mess of opportunities for interpretation! Why? Keeps more lawyers employed I assume....
Comment: For Nixon, are you claiming that he could have been charged and convicted, *even while he was President*, without first being impeached?  Is there evidence to support that?  It is my understanding that he *would* likely have been impeached had he remained President, and presumably this is because Congress thought impeachment was constitutionally necessary.  After he resigned, if he had not been pardoned, he certainly could have been tried and convicted under ordinary judicial processes, but at that point he was no longer a US official.
Comment: @emory Highly unlikely. "Officer" is a specific term with a specific meaning in the Constitution. Officers are delegated a portion of the sovereign authority of the United States, and *must* be appointed either by the President by and with the advice and consent of the Senate, or (if the law specifies this route) by the President alone, the courts, or the heads of federal departments. Most members of the federal government are employees, not officers.


Boolean problems, object is left as a hollow mess

Question: I'm extremely new to 3D modeling, just started today actually. But there have been some problems with the boolean modifier that I just cannot google my way out of. First, when I'm trying to carve out a chunk instead of making a hole right through an object, the two meshes just combine instead of subtracting. The second is when I finally get it to work it leaves my object a hollowed mess. In the screenshots, you can see the left object is the one I want to keep, and the right one is what I want to subtract from the left one. If I select Difference the objects just combine, but if I select Union I get what I actually want but the resulting object is hollow and with some weird planes all over the inside. How can I fix these problems?
Comment: A comprehensive post on booleans can be found here: [Boolean Modifier not working](https://blender.stackexchange.com/questions/34781)
Answer: You have the right operation i.e Difference, and it is working too, the problem with it is John Cena(you can't see it). Jokes aside!
You only can't see the changes because the object is lying on it. If you want to see the changes before applying the modifier, select the object which you are using for hollowing and go to Object Tab. Under View Port Display Select Display as Wire! Now you can see the hollow.

And also after applying the modifier you can delete that hollow helping object to see the hollow. But its risky, arrange it first with the above method and then you are ready to apply and delete.
Have fun!
Comment: Can you attach your blend file?
Comment: Thanks for the answer, but sadly it doesn't solve my problem. In the third screenshot, I have actually removed the hollow helping object out of frame. I don't need to see the changes before applying because this is precise to the mm, but even so, if I display either object as wire or both, it doesn't change the results which are that Difference combines the two meshes, and Union leaves a hollowed mess behind.
Comment: @BaltasarLevíElíasson Difference doesn't combine objects, its just what your are looking for that is hollowing and Union is attaching objects.
Comment: See also https://blender.stackexchange.com/questions/131315/need-help-to-recreate-this-shape-in-blender/131319#131319


Can elbow fitting be used to line up drain tailpiece with trap

Question: I installed a new vanity and the drain tailpipe does not line up with the P trap. Can I use two 90 degree elbow fittings to make this connect? Can elbows connect to elbows directly or does it require an extender in the middle? See the picture of my problem.
Comment: Putting a sharp bend at the bottom of the tailpiece is asking for trouble.
Comment: Can you post a picture from the front showing the left-to-right offset between the drain and the wall connection?
Comment: Can you take a picture of the pipe going into the wall (to the left of the current pic)? Most of the sinks I've seen have a sliding section with a compression fit, just like the one that comes straight down from the sink. This makes it so you can move the trap under the drain (nearly) regardless which sink you use.
Answer: The best repair for this problem is to cut the trap from the drain pipe, glue on an ABS 1 1/2 inch (or same pipe diameter as existing pipe) coupling and than a short section of new pipe long enough to bring the trap under the sink tail piece.
You wll have a little bit of leeway because the trap section can pivot from the threaded connection.
Comment: I have the same problem with a new laundry tub that has a different drain location the previous tub....but I don't understand your solution.  can you elaborate?


Starting out professionally in families/kids/events photography in mostly natural setting vs studio

Question: I am starting out and would appreciate advice on what lenses are ideal for families/kids/events in mostly natural settings with some indoor for events and such.  The plan is to purchase a Canon 7D (even though I'd love a full frame camera since I'm still shooting film) simply because I'm starting out and can't afford the 5D Mark III. And I keep reading the lens is more important than the camera.
Comment: What is your current equipment? This will help in providing advice on what would be best for your needs.
Comment: What does "natural situations" mean? What are the end use requirements? I.e., do you expect to have adequate lighting? Will high-ISO exposures be acceptable to you even with some added noise? Will it be possible to bring in reflectors and/or lights at all? How close to your subjects to you expect to be (closest/average/furthest)?
Comment: Are you invested in Canon? If not, I strongly suggest you look at the [Nikon D600](http://www.neocamera.com/camera/nikon/d600/review) which is a low-cost full-frame DSLR with a complete and professional feature set.
Answer: You should also consider the Canon 5DmkII. I know several who have both and find the mkII to be the better choice at half the price. Sure the mkIII is better, but worth 2x as much? Only for some, and probably not someone like yourself (new to the business).
As for lenses, if you are shooting in low light you will need good AF. A 24-70L is a great lens. I had the Tamron 28-75 and it is a great lens, but the AF was not great in low light. The 24-70 was significantly better.
The 70-200 2.8 is another must for event shooters. I use the non-IS lens and don't wish I had the IS very often.
A 50 1.8 ($80) is a must for any bag. The 1.8 85mm is also a good standby for a decent price ($300).
Look at fredmiranda.com for great deals on Canon gear. Many pros who sell their gear, or amateurs who are always swapping out gear. Great prices and very reputable sellers.
Comment: I second getting the 5DII (or maybe the 6D). The Mk III improves most importantly in ISO- and AF-Performance. ISO is already pretty good on the Mk II. Low light AF on the MkII is indeed a pain (only middle sensor useful for me if at all), but if you know you'll usually have plenty of light (or are good at manual focussing) it shouldn't be an issue. And yes the lens is more important so better put your money in that.
Comment: 5D II is probably the sweet spot for your needs, but also consider older used 1Ds II...better built and better AF than the 5D II, though smaller viewfinder and not as good high ISO. fredmiranda.com, keh.com and adorama.com are all excellent places to look for good used gear.


Can glide ratio be increased with bi-wing configuration?

Question: We all know that increasing the wingspan of an aircraft tends to increase the glide ratio.  Instead of increasing the wingspan, could an extra wing of the same size or less as in a bi-wing configuration also increase the glide ratio?  Which bi-wing configuration would be most ideal for this purpose?
Comment: The reason L/D is increased in wings with large aspect ratio is because the % of wing subject to [wingtip vortexes](https://en.wikipedia.org/wiki/Wingtip_vortices) is smaller and less lift-induced drag is generated.
Comment: @mins, the % of wing subject to wingtip vortices is *all of it, always*. Wider span does mean less induced drag, but the reason is that the wider downwash does not has to be as strong (and therefore the vortices are not as strong, because the vortices are just the shear between the downwash and the still air outside the span).
Comment: @JanHudec: My comment is based on [two Nasa statements](https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/induced.html): 1/ "*The vortices produce a down wash of air behind the wing which is very strong near the wing tips and decreases toward the wing root.*", 2/ "*Induced drag is a three dimensional effect related to the wing tips. The longer the wing, the farther the tips are from the main portion of the wing, and the lower the induced drag*".
Comment: @mins, it probably makes sense in the context of the convoluted explanation (based on potential flow theory?) they use, but it is seriously confusing. Fortunately there is no need to involve vortices in explaining induced drag at all—the energy argument is most elementary physics (just laws of motion and conservation of energy).
Answer: Glide ratio is determined by L/D. If we can increase lift without increasing drag, or decrease drag without decreasing lift, we have a better glide ratio.
Increasing the wing span (for a given wing area => reduce the chord) helps: the longer wing span spreads out the lift creation over a longer distance, thereby decreasing induced drag. Keeping the flow laminar for as long as possible also helps.
Your question is about adding a second wing to an airplane. The problem with biplanes is that they were mainly constructed decades ago, and we associate them with older construction methods and mainly lots of drag, such as addressed in this question. It seems that the classical biplane has no aerodynamic advantages, and always has a lower L/D ratio than a comparable mono wing.
However there are now Computed Fluid Dynamics. There has been work done on biplane configuration with low drag in recent years - many are behind a pay wall, this one is not. Their work found two configurations with high L/D ratios:

Upper wing AoA = 13º
Upper wing forward sweep = 30º
Lower wing AoA = -2.8º
Lower wing backward sweep = 3.5º
Wing profile of both wings = NACA 4412
Both wings 6 ft span and 6 inch chord
Computed L/D = 32.3

The other configuration they found with a high L/D was a canard configuration: one wing in front of the other. If you insist on using two wings, this may be your best bet: one wing mounted in front of the other, in such a way that the back wing is out of the way of the wake of the front wing, or mounted at the optimum AoA for the disturbed flow. Their canard configuration used two different wings, resulting in an L/D of 35.8:

Note that none of the configurations included a fuselage of any kind, so their CFD work would have to be repeated with the fuselage and with interference computations. Fortunately computing power has increased dramatically in recent years.
Comment: Second to last bullet: "Both wings 6 ft soon and 6 inch chord". "6 ft soon"? Was that supposed to be "6 ft long"?
Comment: Fixed it, thx..
Answer:
Instead of increasing the wingspan, could an extra wing of the same size or less as in a bi-wing configuration also increase the glide ratio?

To create lift (over finite span), which is upward force, the wing apply downward force to the air by principle of action and reaction and since the air is free to move, it will accelerate downward. This will increase its energy, therefore the wing must do some work on it and this work manifests as induced drag.
Now because kinetic energy is proportional to mass and square of velocity, while momentum is only proportional to mass and velocity, it is more efficient to accelerate more air to lower speed than less air to higher speed.
At given flight speed, more air can be affected by increasing the wing span, or by having two wings far enough to affect different air. Since the wing affects air to height comparable with the span, the wings would have to be quite high above each other for the construction to be efficient—but such construction would not be efficient mechanically, since it would need very high pylons above and possibly below. Increasing the span is easier.


How will increased $\ce{CO2}$ affect forests and other vegetative areas?

Question: Some researchers contend that increases in atmospheric CO2 (e.g., from anthropogenic emissions) will enhance plant growth in general.

What is the level of that enhancement?
Does the associated climate change simply make it easier for invasive species to propagate?
Or is there really a valid case to be made that at some point, if concentrations of CO2 get high enough, forests and vegetative zones will somehow benefit?
In general, how will increases in CO2 and related climate change affect forests and other vegetative areas?
Answer: If you increase CO2 concentration and keep all other parameters at there current level, then biomass production should go up. The reason is simply that CO2 is one of the building blocks biomass is made of in photosynthesis.
In the real world it's trickier than that of course. Here you have to take into account how natural cycles will be affected by increased CO2 levels. Temperatures e.g. will go up which is expected to be beneficial for biomass production for moderate increases and becomes increasingly bad for higher increases. Precipitation patterns change, wind patterns and therefore soil erosion change etc. etc.
Chapter 7 of the IPCC report deals with the question how climate change affects biogeochemical cycles; biomass production is one of the parameters that go into the carbon cycle.
To my knowledge biomass production is one of the parameters that benefit from moderate temperature increase but are expected to turn to their opposite around the 2-degree benchmark.
Answer: One of the consequences that I find more fascinating with the increased CO2 problem is the changes that affect specific components of the environment. One example that I like is the effect on poison ivy. Researchers at Duke University (Mohan et al., 2006), as part of their Free-Air CO2 Enrichment (FACE) experiment, reported a large change in poison ivy activity when they added CO2. They claim:

"...elevated atmospheric CO2 in an intact forest ecosystem increases photosynthesis, water use efficiency, growth, and population biomass of poison ivy."

For more information on the experiment and the many results they have obtained from it, check here. They have more than 250 publications on the findings of the experiment.
So now, on top of all the other changes, we have to put up with poison ivy on steroids.
However, it is important to keep in mind that

... species that respond strongly to elevated Carbon in [nonresource-limited] experiments are unlikely to also be the most responsive in resource-limited field conditions... [so] we cannot directly extrapolate ... which species will be most responsive to elevated Carbon in the long term.

(Ali et al., 2013)
and

The rise in [CO2] will probably alter the prevalence of invasive species, but the nature of this change is difficult to predict. Whereas alien species may benefit from higher[CO2] in some regions, native species may benefit in others. Plants with certain CO2-responsive traits are likely to benefit from the rise in [CO2], especially if they are growing in ecosystems where those traits are rare. For instance, C3 species growing in C4-dominated ecosystems are likely to benefit from the rise in [CO2] (but under some circumstances may not). Invasiveness and CO2-responsiveness are not clearly linked.

(Dukes, 2000)
Comment: So this sounds like selective species will benefit from increased CO2.  Really good point!
Comment: Yes I remember reading some time ago it was the fast growing species that would benefit most... which would eventually allow more invasive species to get established.
Comment: Hope you don't mind I added more to the answer.
Answer: CO2 can only enhance plant growth when other resources such as nutrients or water are not limiting growth. If N for instance is scarce, no matter how much you increase CO2, plants will not take advantage of the increased CO2 concentration.
Comment: This is true, to some degree, however, increased CO2 also increases water use efficiency, so vegetation that is water limited can also take advantage of higher CO2. Basically, if there is more CO2 available, then stomata can remain more closed, so the plant loses less water.
Comment: It's somewhat incorrect to say it increases "water use efficiency", what increased CO2 does (as you pointed out) is decrease plant transpiration, which can be good or can be bad.   If there's abundant ground water, you want high transpiration, it returns water to the air, which is returned to the ground as rain a day or three later.   Lower transpiration can improve plant adaptation, but it also leads to decreased returned water to the air that becomes rain somewhere else.   It's not always good.
Comment: Nitrogen is thought to be the most important limiting factor for further CO2-driven biomass enhancement, and actually model predictions overestimate future plant growth because most models do not take into account nitrogen feedbacks (Hungate et al. 2003 Science). However, it seems that certain plants might be able to increase soil N-availability through increase allocation of photosynthates belowground, which can stimulate microbial activity and N mineralization (aka priming effect)
Answer: It seems that tropical forests absorb more carbon dioxide than many scientists have believed before. NASA and NCAR scientists have shown that tropical forests absorb 1.4 billion metric tons out of a total global absorption of 2.5 billion metric tons. This estimate is much larger than previous estimates and the tropical contribution seems to be much larger than other areas like temperate or boreal forest.
Previously, most climate models showed mid-latitude forests in the Northern Hemisphere absorbing more carbon than tropical forests. Those results were data-limited and suggested that deforestation was causing tropical forests to release more carbon dioxide than they were absorbing.
The new results seem to indicate the opposite and are based in a more comprehensive analysis of available data.

... reconciles results at every scale from the pores of a single leaf, where photosynthesis takes place, to the whole Earth, as air moves carbon dioxide around the globe.
Answer: It seems that the CO2 fertilization has been over-estimated in past studies.
From Nature Climate Change article,Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization by W. Kolby Smith,    Sasha C. Reed,  Cory C. Cleveland,  Ashley P. Ballantyne,   William R. L. Anderegg,     William R. Wieder,  Yi Y. Liu   & Steven W. Running

Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, 'CO2 fertilization'). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.


Can two-factor authentication (2FA) be added to the Daedalus and Yoroi wallets?

Question: I would like to ask if it is possible to implement 2FA at the wallets of cardano for increased security. As I see it we like to attract people from developing world they don't have access to hardware wallets and definitely the price of them isn't helping.
So is it possible?
Comment: What configuration are you suggesting?  2FA and wallet on the same mobile phone?
Comment: Yes like Google authenticator
Comment: I'd love the multi-sig. I really don't trust password only for anything of high value, so its a huge barrier of entry for others as well I'm sure.
Answer: 2FA (in the traditional sense) relies on a shared secret. By design, this can only work in a centralized environment like an exchange or an online wallet, not with a wallet that interacts directly with the blockchain.
But there are other ways to achieve this, and a multi-sig would be possible and kind of the blockchain equivalent of 2FA. Multi-sig means, for example, you need two private keys to access the funds. (both keys should live on different devices)
There are also more advanced and configurable multi-sig solutions (m-of-n type) like: there are three private keys (m), and two of them (n) are sufficient to control the funds. We will see beautiful solutions here in the future.
Answer: I think it should become more feasible at a lower price, once the wallets start supporting Yubikeys as 2FA, via multisig. So, you would then be able to setup your wallet so that the Yubikey signature is required on all transactions, in addition to the signature from your spending password.


argon2i hashes with GPU using JTR or any other tool please help!

Question: I have been working on an assignment to solve argon2i hashes but unfortunately. I am not able to use GPU with JTR i.e. no opencl mode for argon2. Thus the speed is very slow. Any suggestion how to proceed using GPU based attack?
Answer:
I am not able to use GPU with JTR i.e. no opencl mode for argon2. Thus the speed is very slow. Any suggestion how to proceed using GPU based attack?

This is exactly one of the reasons that argon2 exists.
It was explicitly designed so that hardware other than a general purpose CPU provides only a minimal advantage, if any.
Proceeding with GPU based attacks is probably a waste of a GPU. One of the core features of argon2 is a large amount of memory usage, which GPUs are not exceptionally good at.
Options
Your best bet is to have a large number of normal computers with sufficient RAM, or investigate FPGAs. FPGAs may not be able to provide a worthwhile advantage due to the memory requirement, and they will not be so easy to work with (unless you are already skilled with an HDL).
Neither option will be cheap, and I assume that they are not practical in your situation.
Most likely, you are stuck testing one password guess at a time using your CPU. In such a case, the best that you can do is to use a good word list and hope that the password is weak. Either that, or find some alternative method of finding the password that doesn't involve cracking argon2 hashes.
Comment: Thank you so much for the quick response. :)
I almost hit a threshold for trying. I think I understand you now.
I hope this thread would be helpful for new noobs like me.

Just one more question, does scaling cpu makes a huge difference or not?
Example using a high end i7 rather then lower end dual core?
Comment: @hashcracker101 I'm not sure, it may be limited by memory access times rather than CPU clock speed. You'd probably have to test it to be sure. I would not be surprised if the i7 was faster, but I would be surprised if it was faster by a huge amount (e.g. I wouldn't expect it to be 10x as fast). But I can't really say.


Sausage left to thaw more than 2 hours - is this safe to eat?

Question: I have a package of sausage that I intended to use yesterday. It was taken out of the freezer to thaw at about 4 o' clock. At 9 o' clock it felt fully thawed but we ended up putting it back in the refrigerator where it sits as we speak. When used the sausage is going to be baked in the oven for half an hour. Are we safe to eat this?
Comment: It's the meat temperature that matters. That will depend a lot on the room temperature and how it's packed. The surface will have been below freezing for some of the time, never mind below the 5C maximum recommended fridge temperature. In my cool kitchen, and with how I usually pack food for freezing, I wouldn't hesitate to eat it. But we can't recommend that you do that because we can't know the temperature history.
Answer: The rule of thumb is over 40 F for more than 4 hours.  At best small portion of the sausage was over 40 F for 4+ hours. If bad stuff happened then baking will not fix it. I would eat it.


Was Zoroaster a prophet of Allah?

Question: I have just recently heard about Zoroastrianism. I was curious to see what it was and surprised because a lot of the beliefs are similar to Islam for example monotheism, heaven/hell, prayer in a certain direction, originating from the Middle East, 5 times a day prayer, good vs evil, judgment after death, etc. A savior figure is also believed to come towards the end of times. It came before Islam where Zoroaster claimed he had a divine vision and therefore he began teaching others of monotheism. I have never heard of him before and I don't think he's mentioned anywhere in the Quran, but I'm not sure. Is it possible he was a prophet from Allah?
Answer: There is no authentic evidence whether he was a prophet or not. The correct thing to do is to remain silent and not assume either:

قل إنما حرم ربي ... وأن تقولوا على الله ما لا تعلمون
Say, "My Lord has only forbidden ... that you say about Allah that which you do not know."
— Quran 7:33

There are weak reports attributed to some sahaba that the magians had a prophet and a book which they lost.
Answer: Zarathushtra received revelation from the One God, Creator of the World. The name of God is Ahura Mazdah in Avestan Persian and Ohrmazd in Middle Persian. He is the founder of the Parsic religion which worships exclusively the One God. This is told in an ancient book, the Vendidad.
The mythologic background of this religion is different; pre-Zarathushtra ancient tellings are retold in the view of the monotheistic religion. Mythological deities from the ancient persian religion are «downscaled» to - mostly evil - spirits. Shaytan can be identified with Angra Mainyu (Avestan) in the early Parsic scriptures. In later times, the evil spirits are condensed in the evil spirit Ahriman who can be identified with Angra Mainyu. We find the story of the fall or Shaytan and the reestablishment of the pure world in the end of 9000 years in a later Middle-Persian book, the Bundahishn. Although this book is rather young (written around the time of Muhammadﷺ), the story may be older. It appears in anonymous Jewish literature in the Persian period of Judism without Jewish predecessors. It is possible that the End of the Days was first revealed to a Parsic prophet later than Zarathushtra.
Khorda Bundahishn, 5:1:25-28

Then, Ohrmazd knew, by means of omniscience: "If I do not fix a period
for [his] contest too, he can do so unto My creatures, [as he will
lead the onset and everlasting dispute and confusion; and during the
confusion, he] can seduce [the creatures], and make them over to
himself;" just as, even now, there are many men in the mingled state,
who practise impiety more than piety, [that is, they are mostly
performing the will of the Evil Spirit]. Thereupon, Ohrmazd spoke to
the Evil Spirit: "[I project] the time fixed for the contest in the
mingled state, to nine thousand years;" for, He knew that He would
render the Evil Spirit useless, by this fixation of time. Then, the
Evil Spirit agreed to that covenant, on account of inability to
foresee the end; just as, two men, fighting together, fix up a period,
saying: "Let [us] fight such and such a day up till [night]." Ohrmazd
knew this too, by means of omniscience: Within these nine thousand
years, three thousand years will pass all according to the will of
Ohrmazd; three thousand years [will pass] in the mingled state,
according to the [11] will of [both] Ohrmazd and Ahriman; and, in the
final contest [He ought to render] the Evil Spirit useless, and He
will withhold adversity from the creatures.

Zarathushtra is a prophet of the same One and Only God we call Allah who established a religion worshipping only Him and received the same revelation.
Comment: This site discusses topics on the basis of the Islamic perspective. Your answer doesn't fit here and is rather off-topic. The information shared is nice to know, but doesn't cover the right perspective.

Was Zoroaster a prophet of Allah?


Oatmeal & Lactose Intolerance

Question: I work as a kitchen aide in an assisted living community. I assist the cooks in some aspects of kitchen prep (mostly non-cooking), but occasionally I help in the actual cooking of food. For breakfast, oatmeal is served every morning. The residents enjoy the creaminess of the oatmeal when milk is added, but for those who are lactose intolerant I cannot take that risk. So what alternatives to milk can I use to create a creamier oatmeal?
Comment: what about lactose free milk? it's designed for this very purpose.
Comment: How many are lactose intollerant?  Is it worth making a separate batch just for them?  (although, you might need some differently colored bowls, or something so they'd have an indication that they've been served wrong)
Comment: It seems to me that "assisted living community" is quite broad. Should answers assume that the lactose-intolerant residents are capable of taking responsibility for avoiding lactose, or is it something which must be handled in the kitchen with designated bowls given specifically to those residents?
Comment: What country are you in?
Answer: Almond milk, rice milk, soy milk, coconut milk (but not the kind from the can, something like So Delicious or Silk brand sells), hemp milk, oat milk, or many other nut or grain based milks will work.
Comment: Many, if not all, of these are sold at health food stores and increasingly everyday grocery stores in the US.
Answer: Ironically, one of the many milk alternatives for lactose intolerant people is "oat milk", which is made by soaking oats in water, and retaining the resulting liquor.
Many traditional porridge / oatmeal recipes are made with just oats and water. Oats themselves have a somewhat "creamy" flavour, and remember your lactose-intolerant residents will not have a taste for dairy cream.
I have also seen suggestions for cooking oatmeal in fruit juice or soya milk.
Comment: As an easier preparation, it might be possible to use oat flour to approximate the oat milk (similar to the recipes for risotto that call for adding in some rice flour for creaminess).
Answer: You can try some hydrocolloid thickeners like xanthan gum or guar gum. These generally are used in small amounts and dispersed in a cold liquid. These will help the oatmeal seem "creamier". (FWIW, Quaker Oatmeal's non-dairy flavored oatmeals include guar gum for this very reason.)
Comment: I would not use these. Their mouthfeel is very different from milk mouthfeel, especially for xanthan. Lecithine might be worth a try in very small quantities, but there is a risk of making the oatmeal feel slimy.
Answer: Option 1) Cook the oatmeal a little longer, it will already make a little bit creamier. Add after cooking some fat like walnut oil to add some texture and let it rest few minutes.
Option 2) Put the oat to soak in water in the evening and use it the next morning.

Oatmeal & Lactose Intolerance


What happened to the edit dropdown?

Question: I remember when someone edited my post, I could see what edits were made and if necessary roll them back. Now, it seems to be gone. Did it move somewhere else?
Answer: When not using in-line editing, I see it on the edit page:

Note the box in the top-right corner which states if you select an older revision and save, it rolls back the post.
Comment: I do not get that. I click on the Edit link under my post and do not get the Rev dropdown. It's strange.
Comment: Ahhh, I see what you mean by in-line editing. I have to click the link next to "edited". Thanks.
Comment: I'm sure there's a way to do it with in-line editing, but I don't have actual edit permissions on any site, so I can't check.
Comment: @Troyen I've got edit permissions, but I can't see a dropdown (or any other way of doing it) using inline editing (i.e. left clicking on the "edit" button). I can see that dropdown if I right click on the ["edit"](http://meta.japanese.stackexchange.com/posts/849/edit) button and click "open link in new tab". The other way is to click "rollback" in the [revisions page](http://meta.japanese.stackexchange.com/posts/849/revisions) (as noted by dotnetN00b).
Answer: As you and cypher stated in a comment to Troyen's answer, there are links labeled "edit" and "rollback" in the revisions page.
Another (hack-ish) way to reach the non-inline edit page is by opening the "Edit" link in a new tab or window.

What happened to the edit dropdown?


Seeing SMS messages on iPad and iMessages on iPhone

Question: I receive iMessages on my iPad and not on my iPhone. I receive SMS messages on my phone but not on my iPad. This is really bad and has caused me to miss 2 work leads in the last 24 hours. Where's the syncing in that?
I've read through loads of posts and what people seem to be saying is that as iPads don't do phone numbers, SMS messages will only show up on a phone.  Don't ask me why iMessages can't make it to my phone too. I have spent hours trawling around and have come to the conclusion that my only option to reliably receive all messages is to turn iMessage off.
Answer: If I understand you question correctly you want to receive SMS  and iMessages on both your iPad and iPhone.
If so follow these steps.

If you haven't already done so upgrade both your device to the latest iOS 8 firmware (iOS 8.1)
To fix your iMessage problem, on the iPhone go to Settings > Scroll down to messages > Toggle iMessage on and enter your Apple ID credentials
To get your iPad receiving SMS messages with your phone's number go on your iPad unlock it and keep it on.
Then go back on your iPhone and stay on the page I told you to go in step 2 and tap 'Text Message Forwarding' you should see your iPad and any other Apple devices you have if they are on the same iCloud account (which they will need to be for this too work).

If they are:
Toggle the button next to the name of your iPad and it will ask you for a code which should popup on the iPad.
If not: Go back to the main settings on the device not correctly set with iCloud scroll back up to 'iCloud' tap it and sign out if already signed in and sign in the with the Apple ID used on the other device.


How to declare non-binary decision variables in an optimization problem?

Question: I am working on a logistics problem which require me to find the optimum quantity of product to be manufactured and also to be shipped to satisfy the customer demand. I have made a decision variable $y_{ijp}$
where this variable gives me the qty of product $p$ shipped from node $i$ to $j$. I have done some simple optimization examples previously on Qiskit and D-Wave, but I am not sure how to tackle this problem, since all the decision variables I encountered earlier were binary. Any resources or help regarding this?
Comment: You can try to express the non-binary variable as sum $\sum 2^i x_i$, where $x_i$ is a binary variable. In the end you have binary optimization.
Comment: For Qiskit take a look at the optimization tutorials https://qiskit.org/documentation/optimization/tutorials/index.html. It has converters that deal with integer variable as input. Also there is a warm starting optimizer tutorial around this too.
Comment: @SteveWood, i have gone through these tutorials, the main issue is, while having an integer variable in my model, it adds a constraints, that in turn adds slack variables, which results in lot of qubits being used. I have to get a way past that
Comment: Hi, @MartinVesely, can you elaborate or share a resource related to your answer. Thanks
Answer: What do you mean by "declare"? Mathematically or in some programming language?
Perhaps what you really want to know is how to represent integral or rational variables using binary variables. The answer by Martin Vesely explains how to do it. Basically, you represent a non-binary variable $x$ with a bunch of binary variables $y_j$.
$$\tag{1} x = \sum_{i=0}^{n-1} 2^i y_i + \sum_{j=1}^m 2^{-j} y_j.$$
If you want $x$ to be a float, then $m > 0$ and it determines the precision. Mind that this is not a good idea because your problem now has more variables than the original problem. Also, your feasibility space will be exponentially smaller compared to the solution space. Moreover, the new problem will require much more quantum resources.
If you don't want to mess around with binary expansions like in (1), D-Wave can handle Discrete Quadratic Models. This means the variables could be anything as long as they are discrete. They could be integers, strings or an array of floats. You basically "declare" a variable in a programming sense and just run the annealer.
If you want to use gate-based quantum computation then the approach in (1) is the only way. At this point, just use classical optimization. It really doesn't make sense to use a gate-based quantum computation for such problems.
Comment: Can you share some resource regarding the implementation in (1), this seems interesting. Thanks
Comment: You might want to check this post which explains  this pretty exhaustively https://or.stackexchange.com/questions/6526/how-to-represent-an-integer-variable-via-binary-variables


Web form integrate with views

Question: I working on project where user search for nearest shop. so configured view and output result  user get list of shops. in that result I want to provide a button Email us and when user click on that button have to one form will appear and user fill up the data and click on SEND, Then that mail should be send to the shopkeeper`s mail id and also to the user who sent it.
I want to display a button on every single result with fetching mail field according to user into webform
I used profil2 for user profile and  webform modules.
Answer: we have a webform views module
which may help you I suppose
Comment: Thanks for your response I configured this module but not fulfill my project requirement , but I got something same like my test case on http://www.drupalwoo.com/content/blog/webform-passing-info-through-url.

Web form integrate with views


Legal right to ask for someone bank records UK

Question: My mother is involved in a dispute with her recently deceased partners daughter, who is demanding to see records of the joint bank account she held with her partner. My mother acted as her partner's power of attorney the last 2 years of his life as he became mentally incapacitated, but the daughter seems to think she has right to see records not just after but even before he was deemed unfit to make financial decisions. My mother has nothing to hide, but obviously does not see what legal right she could possibly have to demand this, unless the daughter was accusing her of doing something illegal and went to court to aply for access.
My thoughts are the daughter, as joint executor of her father's will, along with my mother, only has the right to see her fathers sole bank accounts, not joint accounts.
Does anyone have any experience or knowledge on this? Thanks Lee
Comment: Lawfully she isn't required to show unless the other person is asking in an official capacity. `My thoughts are the daughter, as joint executor of her father's will, along with my mother, only has the right to see her fathers sole bank accounts, not joint accounts` If you aren't a lawyer stop guessing and get a lawyer pronto
Comment: Sorry for your loss and sorry for the drama surrounding the passing of this man.
Comment: Hi Pete, Thanks for you message. We are in the process of engaging a lawyer. Its taken some time getting a good recommendation. We have found one today. I was desperate to reassure my mother in the meantime, the daughter has no rights on this particular issue, as she feels quite vulnerable right now.
Answer: You might want to head on over to https://law.stackexchange.com/ and ask the same question.
However from a personal finance perspective this kind of drama is somewhat common when someone is deceased and financial expectations are not met by the heirs.  It sounds like the daughter was expecting a lot more in inheritance than was actually received.  There was probably an overestimation of dad's net worth and an underestimation of the cost of his care toward the end of his life.
Its best not to participate in this drama, and I feel that you are correct that the daughter does not have a right to see the bank account statements prior to dad's passage.  The question is also if she has a right to see it now.
Here in the US a joint account can be setup so the ownership transfers to other account holder(s) up death of an owner.  So in this case your mother would own the account.  If the account is setup as such, then the estate has no right to that money.  You may want to check with the bank for some free advice.  What is the classification of the account now that dad has passed?
When a person grants someone else the power of attorney they have the ability to
act as if they were that person.  Most of the time POAs are limited in scope so If I give a person the POA to register a car in my name, they cannot apply for a credit card in my name (legally).  In this case, however, the POA was probably general so pretty much your mom could do whatever she pleased.
So if your mom took good care of the dad and bought herself some nice jewelry that is perfectly allowable with a general POA.
I strongly doubt this daughter has any rights to the past records and may not even have the rights to the joint bank account currently.
Comment: Again thanks for the link and all your advice. It has been a great help.
Comment: The law in the UK is generally the same regarding joint accounts, in that on death one account holder, all contents revert to other account holder. There are various types of POA in the UK. Not sure what POA my mum was set up as, but it allowed her to take very good care of her partner and make sure he had everything he needed.


How to connect with Metamask and Smart contract?

Question: I am ready with my frontend design. I have only 3 files HTML, CSS, and JAVASCRIPT. So, I didn't create any project or DAPP to have other files. Now next step is to connect with metamask and smart contract for payment. I am not getting exactly what I need to do now. Do I need node js files? If yes, then how? or any other files? How to connect with metamask? I searched for many codes but didn't get anything. Can somebody explain to me?
Comment: In principal you can interact just with JavaScript (without using node.js). Please provide some more details what you like to archive. Is there already a deployed contract in a test network? If yes, the ABI will be needed to write a minimal example.
Answer: maybe this could help
<code>window.addEventListener('load', function() {
    if (typeof web3 !== 'undefined') {
      window.web3 = new Web3(web3.currentProvider);
      console.log('Connected to Metamask!')
    } else {
      console.log('Injected web3 Not Found!!!')
      var provider = 'http://localhost:8545';
      window.web3 = new Web3(new Web3.providers.HttpProvider(provider));
      console.log('Connected without Metamask!')

    }
    console.log("account: " +  web3.eth.coinbase);
});
</code>


Step response overshoot in IIR filters

Question: Is there an analytic expression by which it is possible to calculate overshoot of step-response of second order IIR digital filter? I have tried to search through Mitra's signal processing book and through some other materials, but wasn't able to find it.
Comment: I don't know of a simple one size fits all equation.  Try looking at a book on control systems.  The time response is a very important characteristic in control system design.  Step response is a standard measure of a controls system's behavior.  One approach to get the step response is to find the inverse of H(z)U(z) where H(z) is the z domain transfer function of you're IIR filter and U(z) is the z transform of a unit step function.  U(z)=z/(z-1).  Once you have an expression for the step response, you can analyze the expression for overshoot and other characteristics.
Answer: If we have a second-order discrete-time system with complex conjugate poles at $z_{\infty}=re^{\pm j\theta}$, $0<r<1$, $0<\theta<\pi$ (i.e. with poles inside the unit circle and no poles on the real axis), then we have a transfer function
$$H(z)=\frac{1}{1-2r\cos \theta z^{-1} + r^2z^{-2}}$$
For the moment we assume there are no zeros away from the origin of the $z$-plane. The step response of such a system is given by
$$a(n)=\frac{1}{1-2r\cos \theta + r^2}\left [1+
\frac{r^{n+2}\sin[\theta(n+1)] - r^{n+1}\sin[\theta(n+2)] }{\sin\theta} \right ]\sigma(n) =$$
$$=a_{\infty}[1+d(n)]\sigma(n)\tag{1}$$
where $\sigma(n)$ is the Heaviside step function, $a_{\infty}$ is the value of the step response for $n\rightarrow\infty$, and $d(n)$ corresponds to the ringing of the step response. Consequently, the maximum overshoot of $a(n)$ corresponds to the maximum of $d(n)$. You could try with Mathematica to see if there is an analytic solution for the (largest local) maximum of $d(n)$.
If the system has zeros away from the origin of the $z$-plane, then $H(z)$ has a numerator polynomal $b_0+b_1z^{-1}+b_2z^{-2}$:
$$H(z)=\frac{b_0+b_1z^{-1}+b_2z^{-2}}{1-2r\cos \theta z^{-1} + r^2z^{-2}}$$
In this case the formula for the step response given by (1) still holds with
$$a^{\prime}_{\infty}=a_{\infty}\sum_kb_k$$ and with
$$d^{\prime}(n)=\frac{(d*b)(n)}{\sum_kb_k}=\frac{b_0d(n)+b_1d(n-1)+b_2d(n-2)}{\sum_kb_k}$$
It may be even more difficult to find an analytic solution for the maximum of $d^{\prime}(n)$.
So unfortunately I cannot give a plug-and-play formula for the maximum overshoot, but my intent was to give you some analytical results to experiment with, either with Mathematica, or by using some very simple numerical search strategies.
If everything else fails (Mathematica etc.), I would simply compute $a_{\infty}$ by
$$a_{\infty}=\frac{b_0+b_1+b_2}{1+a_1+a_2}$$
and then actually compute the filter output (e.g. with Matlab's $\tt{filter}$ function), feeding the filter with a step, until you have found the first maximum of the output signal $a_{max}$. The overshoot is then given by $\frac{a_{max}}{a_{\infty}}$. But this may be obvious to you anyway.
Answer: For the general second order section (biquad)
$H(z) = \frac{b_0 + b_1 z^{-1} + b_2 z^{-2}}{1 + a_1 z^{-1} + a_2 z^{-2}} = b_0\frac{(1-qz^{-1})(1-\bar{q}^{-1}z^{-1})}{(1-pz^{-1})(1-\bar{p}^{-1}z^{-1})}$
with a pair of complex conjugate zeros ($q,\bar{q}, q=R_qe^{j\theta_q}$) and poles ($p,\bar{p}, p=R_pe^{j\theta_p}$) the step response $s(n)$, if put on this form
$s(n) = a_{\infty}(1+d(n))$
where $a_{\infty}$ is the steady-state response and $d(n)$ the transient response, is governed by
$a_{\infty} = \frac{1-2R_q\cos(\theta_q)+R_q^2}{1-2R_p\cos(\theta_p)+R_p^2}$
$d(n) = K(\lambda_1\sin(\theta_p[n+1]) + \lambda_{-1}\sin(\theta_p[n-1]) - \lambda_{2}\sin(\theta_p[n+2])-\lambda_{0}\sin(\theta_pn))$
with
$K = \frac{R_p^n}{\sin(\theta_p)(1-2R_q\cos(\theta_q) + R_q^2)}$
$\lambda_{-1} = R_q^2, \quad \lambda_{0} = 2R_qR_p\cos(\theta_q)+R_q^2R_p^{-1}, \quad \lambda_{1} = 2R_q\cos(\theta_q)+R_p^2, \quad \lambda_{2} = R_p$
If there are no zeros,
$\lambda_{-1} = 0, \quad \lambda_{0} = 0, \quad \lambda_{1} = R_p^2, \quad \lambda_{2} = R_p, \quad K=\frac{R_p^n}{\sin(\theta_p)}$
and the expression for $d(n)$ reduces to the expression provided in the other post.
If the independent variable $n$ is treated at continuous, the letter $t$ is used instead of $n$, then the value of $t$ that maximizes $d(t)$ can be found. It is given by
$t_{max} = \frac{1}{\theta_p}\left( \tan^{-1}(-\frac{\ln(R_p)\sin(\theta_p)(\lambda_1-\lambda_{-1}) - \lambda_2\ln(R_p)\sin(2\theta_p) + \lambda_1\theta_p\cos(\theta_p) + \lambda_{-1}\theta_p\cos(\theta_p)-\lambda_2\theta_p\cos(2\theta_p) - \lambda_0\theta_p}{\ln(R_p)\cos(\theta_p)(\lambda_1+\lambda_{-1}) - \lambda_2\ln(R_p)\cos(2\theta_p) - \lambda_1\theta_p\sin(\theta_p) + \lambda_{-1}\theta_p\sin(\theta_p)\lambda_2\theta_p\sin(2\theta_p) - \lambda_0\ln(R_p)}) - k\pi\right)$
The value of $t_{max}$ can then be rounded towards nearest integer and used in the response for $d(n)$. In the expression for $t_{max}$, the value of $k$ must be chosen such that $t_{max}$ is in range $0\leq t_{max} \leq \frac{\pi}{\theta_p}$ and it must be verified that $t_{max}$ is a maximum and not a minimum.
For the all pole case this plot illustrates the maximum overshoot as function of pole radius and angle.

Step response overshoot in IIR filters


Find the joint probability distributed function of random variables

Question: Suppose there are n i.i.d exponential random variables,say $X_{i},i=1,2,\cdots ,n$ with probability density function $$f(x)=\left\{\begin{matrix}
e^{-x} &x\geqslant 0 \\
 0& x<0
\end{matrix}\right.$$ Now let $S=\left \{  X_{i}|X_{i}<\tau ,i=1,2,\cdots ,n\right \}$ be a set of $X_{i}$s satisfying $X_{i}<\tau$.Thus,$|S|$ is a binomial random variable $|S|\sim B(n,1-e^{-\tau }).$
So what is the joint pdf of  $|S|$ and all the $X_{j}\in S$,namely, the joint pdf of the size of $S$ and all the members in it?
Answer: Well, they're all independent, so it doesn't really matter how many there are. And what's more, knowing how many elements are in S doesn't actually provide you with any information about what IS in it; it's just all the random variables that were less than τ. So the number of elements in S, itself as a random variable, is independent with respect to the distribution on each element in S, which are also independent with respect to each other. Now it's kind of wonky to try to take the joint pdf of a discrete random variable and a set of continuous random variables, but really, because each and every one is independent to the others, it's sufficient to get the distribution of each of the elements and just understand that the joint distribution is just the product of it all.
Really, what this is kind of saying, is, you have n radioactive atoms, each having a halflife of ln(2) second (ok, I should say decay time constant instead of half-life because there's nothing special about the number 2 when dealing with e, but just to put it in common terminology and a comprehensible situation), and of those n, |S| of them decayed within the first τ seconds. Hopefully you see that knowing how many of the n radioactive atoms in the set decayed before τ seconds pass doesn't make a lick of difference for the probability density on when any one atom decayed within that τ second period of time. Nor do they have an effect on each other. They're all still independent. It would only be if you did something like, keep the m atoms that lasted the longest among the |S| that decayed before τ seconds passed, that they would be dependent. But no, you're keeping all the atoms that decay before τ seconds pass in your set. What is the distribution just on those |S| elements? Well, that's just a simple application of Bayes's theorem. The probability of it decaying within time τ seconds is 1-$e^{-τ}$. So distribution on the |S| elements is just the original distribution divided by that over the first τ seconds, and 0 thereafter:
$f(x)=\left\{\begin{matrix}
0& 0>x\\\frac{e^{-x}}{1-e^{-τ}} &τ>x\geqslant 0 \\
 0& x\geqslantτ
\end{matrix}\right.$
and this is for each and every one of the |S| variables that make it before the threshold - the atoms that decay fast enough.


settings for editing in cs4

Question: What initial setting should I be using in Premiere CS4 if I shot video on a Samsung HMX-q10 camera but shot in standard definition? When I tried DV NTSC the video looks very bad, like it's somewhat pixellated. When I view it on Windows media player the video looks good.
The properties on the clips are: 720x480 59 fps.
Comment: Could you maybe include a screenshot of how the video looks when imported in a DV NTSC sequence? Your footage seems to be NTSC as it is 720x480 interlaced (according to the specs of the camera).
Answer: Try applying a de-interlace and make sure that the preview window is at full quality.  If you play back interlaced footage as progressive without deinterlacing, then every other frame only has half the normal information which would look pretty bad.  You should be able to adjust it under Interpret Footage from the footage properties.

settings for editing in cs4


Esri Distance Calculation

Question: What is the difference of using esri/geometry/geometryEngine distance method and GeometryService length method? Which is faster and capable of calculating distance on Mouse Move event on client side in JS API?
Answer: The geometryEngine should be faster as it runs client side.  Although there would be the slight slow down as the module gets loaded during your site's initialization, you don't need to wait for a callback function as you would with the GeometryService.
If you're doing it with the mouse move event, definitely stay client side with geometryEngine.
Answer: @Branco is right, but its also important to note that the geometryEngine distance and length methods are only capable of generating geodesic calculations for WGS84 and Web Mercator maps.  As such the clientside library should not be used to calculate planar measurements in map projections that distort distance.
see this blog for more information.
Comment: So this is true for all `geometryEngine` methods? I'm trying unsuccessfully to use `nearestCoordinate` with a projected layer, but no chance it's going to work then ? Is there any other alternative for finding the closest feature for a clicked location? Pity this isn't explained clearly in the doc, I've lost a lot of time.

Esri Distance Calculation