How to install latest git on Debian 8?

Question: I have some problems with git-lfs and I think that upgrading to the latest git can fix this problems. Current version of git in Debian is 2.1.4, current stable version on official site is 2.6.4. Can I only build from source or maybe can I add some external repository?
Comment: Installing from source is a procedure that can vary from application to application. In Git's case, the default install from source (at time of writing) is actually to the user's home directory: see its [INSTALL](https://github.com/git/git/blob/master/INSTALL) file. So, such an install should be fairly painless to back out from if for some reason it doesn't work for you, especially if you take a system snapshot/backup beforehand.
Comment: similar question : http://unix.stackexchange.com/questions/33617/how-can-i-update-to-a-newer-version-of-git-using-apt-get
Answer: As of December 2015, Debian stretch/sid has git version 2.6.4.  If you don't want to upgrade your entire distribution, you can look into apt pinning to bring in only git and any necessary dependencies from stretch/sid.  However, many Debian folks will tell you this sort of thing is a bad idea, so building from source or waiting/asking for a backport are the only officially recommended approaches.
Comment: Thank you, I added to the `/etc/apt/sources.list` line `deb http://ftp.us.debian.org/debian testing main contrib non-free` and after this `sudo apt-get update` and `sudo apt-get install git/testing`.
Answer: Backporting git from Debian testing, unstable, or experimental is fairly trivial. See How can I install more recent versions of software than what Debian provides?. Something as simple as apt-get source -t unstable git, followed up debuild -uc -us inside the source directory should work. Note that these two commands should be run as user, not root.
You might have to install some build dependencies, though. apt-get build-dep git will probably work in that case. Note that this command
is run as root, not user.
Please comment if you are trying to do this and need more details.
Answer: This worked on a Debian docker container(php:5-apache).
NOTE: This currently(Mar 2018) doesn't work with an error of libc6-dev dependencies.
 RUN echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" >> /etc/apt/sources.list \
         &&      apt-get update              \
         &&      apt-get install -y git      \
         &&      apt-get clean all

Answer: This might help:
$ sudo add-apt-repository ppa:git-core/ppa
$ sudo apt-get update
$ sudo apt-get install git

Comment: ppa works only on Ubuntu not Debian. Please see my answer.
Comment: I am getting 404 from this repo at `update`
Answer: What Svetlin Tonchev suggested would work out of the box only if OP was using Ubuntu, which isn't the case here. However, when running add-apt-repository the added source will depend on the name of your OS. For example, if you go to /etc/apt/sources.list.d/ you might find a file called git-core-ppa-jessie.list (or similar) containing the following lines:

deb http://ppa.launchpad.net/git-core/ppa/ubuntu jessie main
deb-src http://ppa.launchpad.net/git-core/ppa/ubuntu jessie main

However, such repository does not exist and that's why OP got a 404.
A possible solution to this specific issue would be to manually edit the above file and replace jessie with xenial.

How to install latest git on Debian 8?


Pre-populate fields using visual flow

Question: I am creating an opportunity by clicking on new opportunity related list button on campaign.I am using url hacking to pre-populate certain fields. The problem is as the number of fields to pre-populate becomes bigger the more clumsy the url becomes.I am wondering if this can be done easily with flows ? if yes how?
Answer: Yes this can be done with flows. You need a flow and a button. The button will launch the flow and it can also send in variables just like you do with the URL hacking. The flow would start with a lot of variables being sent in, then probably contain a screen to get any additional values and then a record create element.
So overall, it's still big and clunky, but it's now in a supported feature.

Pre-populate fields using visual flow


UIScrollView isn't scrolling to correct location

Question: I have a UIScrollView with several objects in it which, when selected, I'd like them to come to the centre of the view. I am using the following code to do this.
CGRect frameToScrollTo;
frameToScrollTo.origin.x = (centerOfLabel - 150);
frameToScrollTo.origin.y = 0;
frameToScrollTo.size.width = 300;
frameToScrollTo.size.height = 44;

[self.monthsScroller scrollRectToVisible:frameToScrollTo animated:YES];

I have done tests to make sure the CGRect I'm creating is correct, but the UIScrollView always scrolls leaving part of the rectangle off screen. This only happens when I have content insets applied. My content insets change depending on the content so I can't do anything to remove these.
Can anyone please suggest a fix for this?
Thanks in advance.
Ricky.
Answer: Sorted it out. I substituted -scrollRectToVisible:animated: with -setContentOffset:animated:.


Comparison of C-index between Cox Proportional Hazards model and Fine-Gray model

Question: I have run two models with the same covariates, one for cox proportional hazards model and another for Fine-Gray competing risk model.
The C-index for the cox model is about 0.81 and that of the Fine-Gray model is around 0.79. Based on this alone, can I interpret that the cox model is better able to differentiate between high-risk and low-risk patients?
Answer: First, the C-index isn't a very sensitive way to compare survival models. Frank Harrell, who introduced the C-index into survival analysis, agrees with that assessment.
Second, you can't compare point estimates (e.g., of C-indices) without also knowing the error in the estimates. In my experience, error estimates in C-indices are likely to be greater than the 0.02 difference between the values of 0.79 and 0.81. So it's not clear that there is a reliable difference here at all.
Third, and probably most important, the Cox model and the Fine-Gray model are modeling different things. Presumably you have a competing-risks scenario where you evaluated a single type of event with both a Cox model (right censoring at times of other event types) and a Fine-Gray model. I find the R competing risks vignette to be helpful in comparing the two approaches.
The Cox model evaluates the hazard of that event type if an individual is still at risk for that event type. In a combined Cox competing-risks model you can get proper estimates for the probability of experiencing each risk over time. But the losses of individuals to other types of events make it difficult to interpret the model coefficients in terms of the overall risk of a particular event type.
The Fine-Gray model evaluates the "subdistribution hazard" for that event type in a way that includes individuals who have already had a different type of event. That tries to estimate the overall risk of having that particular event type, with regression coefficients directly related to that estimate. But if you model all of the competing risks that way, it's possible to have the estimated sum of event probabilities exceed 1.
As they model different things, the two types of models really shouldn't be compared that way at all.


Fetch mail from MSN/Windows Live! in Evolution

Question: I'm trying to sync a Hotmail/Windows Live/MSN email account to Evolution - however I'm unable to do so with both POP and IMAP. If I understand correctly this is because Microsoft blocks all email clients other than Outlook. Is there a way around this?
Answer: After a lot of hunting through old threads on the forums. I was mistaken that POP is disabled for all non-Microsoft clients. Here are the settings that worked for me.
In Evolution go to Edit -> Preferences. Choose your MSN/Live email account and select "Edit".
Receiving Settings

Server Type: POP
Server: pop3.live.com:995
Username: Windows Live Email Address
Use SSL Connection: SSL encryption
Authentication Type: Password

Sending Settings

Server Type: SMTP
Server: smtp.live.com:587
Use Secure Connection: TLS Encryption
Server Requires Authentication
Authentication: Plain
Username: Windows Live Email Address

As a side note. When you try to send mail for the first time it will fail. You will get an email from Windows with a link to confirm you are a person and enable this functionality. After that you can Send as expected.
Answer: Hotmail does indeed support POP3:

http://news.softpedia.com/news/Windows-Live-Hotmail-POP3-Support-Now-Worldwide-106772.shtml

The details for connecting are also included in the article.


QGIS Raster Calculator resample algorithm

Question: I want to substract two covering raster sets in the Raster Calculator in QGIS to get a difference map. The raster sets have different extents and raster size.
How does the algorithm of Raster Calculator exactly interpolates the difference raster?
Answer: I am not sure what do you mean by raster size whether it is a synonym of raster extent or not, or you mean a raster resolution. Anyway let me explain how raster calculator works when you two raster data of different extents.
When you have a situation that you need to do a calculation involving two raster data of different extents as in the following example, you need to choose the output extent by selecting one of the input raster data (Raster bands) as you can see below:

Select a an input under Raster bands
Click on Current layer extent
The X min, Y min, X max, and Y max will be updated based on the extent of the selected input raster. In the above image DEM_Sub@1 was selected

If I select the second image: DEM_Full@1 and click on Current layer extent, the extent will be updated:
Comment: Thank you for your answer. Now, one point of my question is explained. With raster size i mean raster resolution ;-). The second part of my question is: Which interpolation method it uses (e.g. Nearest Neighbour, IDW, ...) for the cells of the new difference raster?
Comment: @CanisLupus the resolution of output image depends on the resolution of the selected output extent, and generally if you have two different images with different extents (one smaller and one bigger), it is better to choose the output extent of the smaller image because this is the overlap between the two images. For the interpolation method there is no relation between the output result and interpolation because you are not interpolating point data to create a raster, it is already a raster data. But if the raster was created from points data, the output result will depend on the input data.


UK Transit Visa (DATV) needed or not needed?

Question: I am based in India.I will be travelling to France & Spain for holidays with my wife on 3rd Apr 2017.
So i have applied for Schengen Visa  and expected to get it by 25th March i.e around 8-9 days prior to my travel dates.
Main issue:
We are returning back from Madrid to India on 15th April & my flight from Madrid is having layover in London for 1 hr 50 minutes. After that i have flight from London to Mumbai (British airways)
In such cases while returning back to our country , do we still need UK TRANSIT VISA even for 2 hrs layover at London...
Please guide me.
PS: I do hold Valid US visa & my wife doesnt hold it.
Thanks in advance
Answer: In short, because you have a valid US visa, you do not need a DATV, while your wife does need one.
See Is there a way to find out if I need a transit visa for a layover in the UK? for more details


Change filesystem type from "Linux" to "Linux root (x86-64)"

Question: I just partitioned a new GUID drive, and accidentally chose "Linux filesystem" (0FC63DAF-8483-4772-8E79-3D69D8477DE4) instead "Linux root (x86-64)" (4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709) for my root partition. I already downloaded and installed the system. Is it possible to change the partition type without reinstalling/repartitioning?
Answer: OK, I must have been blind.
In fdisk there is an entry
t   change a partition type

Just select it, choose the partition, and enter 24 (or l to check the number first)


Kinds of anti aliasing?

Question: I'm looking into the newer OpenGL's with GLFW, but I'm stuck in a decision. What kind of anti aliasing is the best, or something that makes it look real, not "real". I don't want the picture blurred, I want it clear. I'm thinking about super sampling but that does not seem like the best due to that it uses a ton of resources. What's your experience with what AA and did you like it? Can someone explain all the types of AA? Thanks!
Comment: @BorealGames I doubt FSAA has been standard for years; it is simply too slow.  MSAA has been a standard for awhile and nowadays, postprocessing approaches like MLAA and FXAA are becoming fairly standard.
Comment: This question is very poorly specified. It's not clear what you mean by "look real, not 'real'", or how anti-aliasing affects that.
Comment: I don't want a blurred image, I'm looking for a kind of anti aliasing that is able to clear the image without remove anything or  like I said blur it.
Comment: FSAA is pretty standard.  It works by rendering at higher resolutions and downscaling.  MSAA is newer, and only does this supersampling for the depth and stencil buffers, which is much less costly since the fragment shader only needs to be run once per pixel.
Comment: @user1870398: "*I don't want a blurred image*" That's not clearing things up. What exactly do you mean by not being "blurred"? Any antialiasing technique will ultimately introduce "blur" of some form. The question is, will it be the correct "blur"?
Answer: There was a SIGGRAPH 2011 course on antialiasing in games, which will probably give you far more information about many more types of AA than you really want. :)
When you run a typical PC game and in the options it gives you a choice of "2X, 4X, or 8X" antialiasing, it's referring to multisample antialiasing, MSAA.  This stores super-resolution frame buffers and resolves visibility per sample, just like supersampling - but the pixel shader is run only once per pixel, not per sample, and the color it outputs is replicated to all samples in that pixel.  That improves performance, but MSAA still requires a lot of extra memory, and induces complications with things like deferred shading.
The latest hotness is to do postprocess antialiasing, where you render the frame normally without MSAA or anything else, then run a filter on the image afterward that tries to identify sharp edges and blur along them or otherwise "repair" them to remove jaggies.  This has been quite successful since it's faster and consumes much less memory than MSAA, and it's relatively easy for developers to add to their games.  (In fact, GPU vendors are even starting to add postprocess AA options to their drivers, so the game doesn't even need to support it directly.)  There are many flavors of postprocess antialiasing; the major ones are detailed in that SIGGRAPH course.  One of the most popular types currently is fast approximate antialiasing, FXAA.
Comment: "*so the game doesn't even need to support it directly.*" Wonderful. Because the only thing better than the driver going behind the programmers back is the driver blurring an image that didn't need antialiasing (see: text), or God help you, already had *real* antialiasing applied to it.
Comment: +1; I've personally come to prefer PP AA because, in addition to the reasons outlined in this answer, it plays much nicer with forced AA through driver control panels (and my experience is that a *lot* of folks do this and will then blame you - as the developer - if things go bad: it's the old "but everything else works!" thing).

Kinds of anti aliasing?


Using a Tamron 70-300mm for Nikon on my Canon EOS 200D

Question: Maybe a dumb question for Pros like you but I really have no idea: I got a Tamron 70-300mm F4-5.6 A005 FOR NIKON - but I have a Canon 200D (it was gift, because the person doesn't need it anymore). Is there any possibility to use it on my camera with an adapter or something else?
I can't find any information about this so I hope somebody can help me here. I am an absolute newbie in this theme, so please explain it with simple words :-D
Thank you in advance,
Elena
Answer: There are adapters that convert Nikon lenses to Canon. Prices vary greatly, and the result is never satisfactory. You will lose most of the automatic features like focus, aperture control, and image stabilisation. You'll find more information here. That article also talks about one particular adapter model. You'll find more on Amazon.
I suspect you would be better off selling the lens on fleeBay, and using the money to buy an equivalent Nikon lens. You'll lose a bit of cash, but it's worth it in the long run.


Why is the month of Aprill masculine?

Question: In the first line of the General Prologue of The Canterbury Tales, the month of April is given a masculine pronoun:

Whan that Aprill, with his shoures soote

Why is this?
Answer: There have been a couple of different explanations given for this, but the upshot seems to be that there's nothing particularly significant about the masculinity of April - it was more a product of the way language was used at the time than any kind of symbolic statement about masculinity.
In his Notes to the Canterbury Tales (2014), Prof Walter Skeat says that the masculinity of Aprille is derived from that of the Latin Aprilis. Latin was of course much more widely used, especially in literature, in Chaucer's day.
However, in his notes published here and based on those of Alfred Pollard, Prof Edwin Duncan cites Skeat and then points out that:

as his in Chaucer's time was the neuter, as well as the masculine, genitive, there is no evidence that Chaucer here personified either the month or the wind as a masculine.

The reason why "his" was used as a neuter pronoun is that the word "its" didn't exist yet. According to Etymology Online, the neuter possessive pronoun "its" dates back to around the 16th century, well after Chaucer's time. (Thanks to @GarethRees for pointing this out to me.)
Answer: This is possibly a reference to astrology.  In western astrology, April is regarded as a masculine month.
April is the month of Aries, The Ram, a masculine sign.  It is ruled by Mars, a masculine planet.
As astrology was more highly regarded in Chaucer's time than today, he could well be making a reference to April's astrological masculinity.
However, to be sure of this as an explanation, a reference to a feminine month using feminine pronoun is needed.  I can't immediately think of such a reference.
Comment: "April is regarded as a masculine month." citation?

Why is the month of Aprill masculine?


Intel DG965WH Motherboard

Question: what power supply do i need to get for this board. I believe I bought the wrong item. I got Ultra 600w X-Finity Power Supply w/2 80mm but I notice the fan is not spinning in the power supply.
Answer: Fan is not spinning on the power supply? It could be DOA. Or you may have not set it up correctly. Do the motherboard fans/lights start up?
Power Information for the DG965WH MB
To know what your motherboard needs (power wise) you should read your motherboard manual. (Link below)
Important links:

DG965WH page from Intel website
Tested Power Supply List
DG965WH manual

600w should be enough to run your MB but also take consideration into what other components require power too.
Answer: The fan inside the power supply is usually not controlled by the motherboard. As long as the motherboard make the powersupply 'on' then the fan should spin. Sound like it is broken

Intel DG965WH Motherboard


Very short story about a macho astronaut on an all-female planet

Question: A friend of mine remembers a very short (just a page or two) science fiction story in which a macho astronaut landed on a planet of women, who were first amused then irritated by his chest-beating mannerisms.  When he insisted on proving his valor against mortal peril, they injected him with a disease that had a fifty-fifty chance of killing him.  Alas, he cannot the author (Joanna Russ?  James Tiptree, Jr.?), but it was definitely by a woman; nor where he read it.  However, the story was from no later than the 1980s; and the 1970s are more likely, since he was still reading SF on a regular basis then.
Comment: It feels a little unsubtle for Russ or Tiptree. I have a reasonably complete collection of both authors and cannot find a story like that from either.
Comment: @JohnRennie yeah... Tiptree's version of this would be [Houston, Houston, do you read?](https://en.wikipedia.org/wiki/Houston,_Houston,_Do_You_Read%3F) and it's both subtler and crueler. I feel this describes most of Tiptree, really :)
Comment: @JohnRennie Yeah, if it had been one of those two, he probably would have located the story himself.
Answer: "When It Changed" by Joanna Russ (1972, in "Again, Dangerous Visions") is so famous that it hasn't been in an answer probably because of the mismatch: the women did not try to kill him by injecting a disease. And "Men!" -- plural -- landed.
But it keeps nagging at me as a close match in several ways. I still remember it sharply from freakin' years ago. After the first alarm call of plural "Men!" have landed, the conversations are with a single man.
They (it says "four of them") landed on the planet Whileaway, knowing only that there had been a plague on Whileaway. It had killed all of the male colonists generations back. The female colonists had perforce managed to make a successful life and community on the new planet for thirty generations.
After that plural mention, all of the conversations are between several colonists and a single man. He is rather obnoxious. Several times he repeatedly asks the people on this planet, "Where are all your people?" and "Where I come from, the women don't dress so plainly."
Then there are conversations between the colonists and another man, in a similar pattern.
Each one is dismissive of the colonists as "people". Each one makes it clear they have come for breeding and new genetic material.
Although the men are egregiously dismissive, overbearing, and tactless enough to make the conversations seem painfully long, the story is short, only about three pages.
It is told in the first person.
The nearly-attempted murder is here too. (Just not an injected disease agent.) The narrator's partner raised a rifle to shoot the man with whom they had been conversing, just after he had gone into his provided quarters and shut the screen door.
It was unsuccessful only because the narrator pushed the rifle barrel off aim as it was firing.
And that becomes clear that that was When It Changed.
Comment: He says it's not this one.  The injection with a 50% chance of killing him was definitely part of it.
Comment: Dang! That said on behalf of both of us. So, we both keep looking.


Large gap between garage door and floor - seal into slot?

Question: There's a large-ish gap between the bottom of our garage door and the concrete floor where rodents are getting in. Since the gap is larger than standard seals, an exterminator mentioned a product he saw that was a seal that inserts into some sort of long slot... but he didn't know who made it. Does anyone have any ideas?
Comment: Please post a phot and the measurement of the gap.  In theory you can get anything made of rubber and glue it to the bottom if the door.
Comment: Rodents will need something hard like cement or metal to stop them, if the gap cannot be reduced.  Rodents can chew though any soft stuff like wood/plastic/rubber/foam.
Answer: If the gap is uniform along the whole length of the door, you may be able to adjust the limit screws to lower the end height.
Check if your door has them. They may be located under the light bulb protection.


Source of loading value to the register or memory location

Question: When we load a register or memory location with a value (e.g. MVI 3A or MVI 53), what initializes register or memory location with that specific value? It is the CPU who performs the initialization, right? But where are those values drawn from?
Comment: The processor has a FETCH mechanism.  That mechanism not only fetches the `MVI` opcode from memory, but also the `3A` byte that follows it (it's essentially two FETCH operations.  It knows that it needs to do the second FETCH because the opcode is `MVI`).
Comment: They're drawn from memory, just like the processor instructions are.  In the instruction `MVI 3A`, the `MVI` instruction byte immediately precedes the `3A` operand byte in memory.  When the `MVI` instruction is fetched from memory into the processor, the processor knows that the following memory location will contain the operand.
Comment: @RobertHarvey : Yes, they are drawn from the memory and executed by the CPU. But the value itself - does the CPU "create" those zeros and ones or are they created when encoding process ends and some kind of inner stage generates those impulses and implies them to opcode and instruction?
Comment: @RobertHarvey : Seems like a decent explanation for me. Thank you!
Answer: Note: since you did not mention which instruction set architecture you are asking about, I have to make some assumptions and guesswork in my answer. Also, it looks like the textbook or the learning material refers to an architecture that is not the same as today's "desktop CPUs", so please cite the name of the textbook or learning material so that we know what architecture it is referring to.
Without further information, my internet search seems to indicate it may be referring to this book: Microprocessors and Microcontrollers: Architecture, Programming and System Design 8085, 8086, 8051, 8096

The I in MVI refers to immediate. In assembly programming, an "immediate value" is a value that is directly encoded into the instruction itself.
For simplicity I will first focus on the case of architectures having a fixed instruction size, say, each assembly instruction is 32-bit.
Part of the 32-bit is used to store the opcode that specifies the operation, such as addition, subtraction, load from memory, store to memory, branching, etc. MVI is the mnemonic for an opcode that will set a particular register to a particular value.
The remaining bits of the 32-bit instruction are used for purposes depending on what the opcode is. Different opcodes use those remaining bits in different ways.
For MVI, some of the remaining bits specify which of the CPU register will be updated with that "immediate value". The rest of the bits are used to encode this immediate value.
I should emphasize that, typically, the CPU does not need to make an additional memory request to fetch this immediate value. The reason is that the CPU has already loaded the entire instruction (32-bit) from memory, before it can perform instruction decode step on it. Thus, the opcode, the register identifier, and the immediate value are all loaded into the instruction decoder.
The instruction decoder can pass this immediate value into the arithmetic and logic unit (ALU) via one of the ALU input ports. The ALU will be set to perform nothing - pass the same input value as output. The register file is configured to accept this value from the ALU output port, and store it into the destination register, according to the instruction decoder's parsing of the MVI instruction.
The immediate value is technically part of the instruction.
Similar instructions exist across a lot of architectures, though details might differ.

In some cases, the architecture word size is 32-bit, meaning that the ALU and memory operations are 32-bit wide, and the instruction size is also fixed at 32-bit. Since the opcode and the register identifier took up some of the instruction bits, it is not possible for the immediate value to be 32-bit. Instead, the immediate value is limited to fewer number of bits. For example, if opcode is 6-bit and the register identifier is 5-bit (supporting up to 32 registers), the remaining number of bits available for the immediate value is 32 - 6 - 5 == 21 bits. Depending on the architecture, this 21-bit immediate value might be interpreted as signed or unsigned.

In some other architectures, the immediate value is not packed into the instruction itself, but is stored immediately next to it.
|| Address | Instruction data ||
||    0    | MVI              ||
||    2    | 0x1234           ||
||    4    | whatever instruction that follows ||
For these architectures, it might require an additional memory access. The MVI instruction at address 0 causes the instruction decoder to treat the data at address 2 not as instruction, but as the value for the MVI instruction.
Although this design allows the MVI instruction to load the full-width data (16-bit) into the register, notice that it creates a danger for a branch instruction to specify address 2 as the jump target. Since the data can be any arbitrary 16-bit value, a branch instruction that lands at this address will mis-interpret that data as an instruction opcode (to whatever opcode that happens to have the same bit patterns as that 16-bit value), and therefore will execute an arbitrary instruction that is unintended by the assembly language programmer.

In yet some other architectures, it is possible that they do not have the equivalent of MVI at all. Instead, the value must be loaded from memory, typically named a LD (load).
|| Address | Data / Instruction ||
|| 0       | LD R1, (address) 128 ||
|| 2       | whatever instruction that follows ||
|| ... | ... ||
|| 128 | 0x1234 ||
Comment: You wrote this "The rest of the bits are used to encode this immediate value.". What is encoding process (detailed), and what is decoder (can't find it on google)? Textbook: Halsall & Lister: Microprocessor fundamentals (gives examples of 8085).
Answer: MVI (Move Immediate) copies an immediate value from the memory location that is adjacent to the MVI opcode itself (the "operand").  The value is baked into the machine code when you assemble it, and will exist in the code segment (the memory block that contains the executing instructions).
Answer: Generally in assembly languages there are both instructions and operands.
When loading a value, an instruction will have an operand specifying the data the operation needs. This could be the value of another memory location or a literal value, similar to how one can have an integer or pointer to integer in C. Perhaps there are different machine code instructions for the two varieties, or perhaps there is an indicator built-in to the operand to specify how to interpret it. At the assembly level, this is irrelevant.
When the CPU loads the instruction and executes it, it will either store the literal value where it belongs or load the value from memory and store it.
This means the values are drawn from the instruction's operand, but the value could be another level of indirection deep and stored at another memory location.
Comment: There are also instructions that have no operands (the simples is a NOP) or where the operand is implicit in the opcode itself. This is however just true for von-Neumann-architectures. Other architectures like neuronal networks or quantum computers work totally different from this.
Comment: Not necessarily.  A NOP instruction in a hypothetical instruction set *could* have an operand ... that it ignored :-)


How can I use Shearing and Loopsliding correctly?

Question: I am following a tutorial (https://www.youtube.com/watch?v=KzA5fOIq8Qw) about modelling a chair, when Shearing and Loopsliding come up at 12 min. It´s recommended to hold down alt or click C in order to activate the loopslide effect of a sheared mesh. I basicly selected two vertecies (one on each side) at the edge of the mesh and want to move the vertecies higher along the face, but the shortcuts alt or c won´t work.
I think it makes sense to use G before every other shortcut, but that didn´t help either.
Is there another way for this? Here´s the file https://www.dropbox.com/s/1tez5qwvzopn3xk/soborg.blend?dl=0
Answer: You just have to doubletap  G first of all.


Using Lightning Out for external apps is beta right now, does it mean we cannot use it in production?

Question: Using Lightning Out for external apps is beta right now. However considering that using Lightning Out for Visualforce page is allowed in production org therefore technically we can use lightning out for external app as well in production. Kindly let me know is there any technical limitation for not being able to use Lightning Out in production as of now.
Answer: Lightning out for visual force is not in beta so you are fine to use it
https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/components_visualforce.htm
Lightning out for any app outside salesforce is in beta and technically should not be packaged
https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/lightning_out.htm
You mention VF in your question as a supporting fact so not sure which you are asking about.
Comment: Hi @Eric, the reason I mentioned VF as supporting fact is that both VF and external app has the same dependency i.e. creating a lightning out dependency app and CORS configuration in Salesforce instance. If one is GA then technically there is nothing which is stopping me using that dependency app in external application. –
Comment: Hi @Eric, If i understood correctly , i should be able to use lighting out for external app in production but should not package it because it is not GA or there is anything which Salesforce may rollback e.g. blocking CORS for lightning out for external website? In short should i not even propose to the customer just because it is in BETA release?


Who wrote the equation $c=\lambda\nu$ for the first time?

Question: I could not find who wrote the equation $c=\lambda\nu$ for the first time. Neither I found a name for this equation. A user from Physics forum thinks it is too obvious for anyone familiar with wavelength and frequency, and once light has been understood traveling as electromagnetic waves, someone must has described it with this equation. Does anyone know anything more about it?
Comment: Hi Mauricio, maybe. I just wondered about this equation in particular, since its simplicity is charming and wondered whether it can be applied also to G since both are waves at same speed.
Answer: Relations between the frequency and length of a string are known since Antiquity, but a more precise mathematical treatment would have to wait until the invention of calculus.
The wave equation was first studied by Brook Taylor (1713) and later by Jean d'Alembert (1746). (As for who really did it first check this answer: Who discovered the wave equation?). I was not able to find the explicit equation from commentary of their work but Jakob Hermann in Phoronomia (a commentary on the work of Taylor and Newton) in 1716 writes:

$$V=\lambda/T$$

where $V$ is the speed of sound and $T$ the period of oscillation. The rest of the analysis of Hermann was wrong. Source: The Evolution of Dynamics: Vibration Theory from 1687 to 1742 pp
The solutions of the wave equation are of the form $f( x/\lambda-\nu t)$ (in the argument you have $x$ position, $\lambda$ wavelength, $\nu$ frequency and time $t$), which can also be written as another function $g(x-ct)$ (where $c$ is the speed of the wave). For the simplest case (describing sinusoidal waves), it leads to your formula $c=\nu\lambda$ (known as linear dispersion relation).
As for light. Thomas Young showed definitely in 1800 that light behaves like a wave using a double slit experiment. Experiments showed that light in air seemed to follow that simple linear relation $c=\nu\lambda$ when it is not travelling inside a media.
In 1855, Wilhelm Weber and Rudolf Kohlrausch suggested that the speed of light was equivalent to the ratio of electric and magnetic constants. In 1864, James Clerk Maxwell, compiled all the different equations of electromagnetism and finally showed that electromagnetic fields propagate as waves, and in vacuum these waves follow $c=\nu\lambda$ where $c$ was the calculated to be equal to the experimental value for the speed of light. So visible light is a type of electromagnetic wave with linear dispersion.
In the comments you mentioned gravitational waves. In 1915 Albert Einstein published his theory of general relativity (suggesting that gravity is related to the curvature of space-time), and in 1916 he derived the equations for the gravitational waves. These equations are very complex and describe the distorsion of spacetime, the same arguments that one needs to write the equation. However for very simple spacetimes geometries it also follows $c=\nu\lambda$, where $c$ is the speed of light. The fact that for light and gravitational waves the speed is the same is related to relativity, where $c$ is the maximum speed a wave can travel and it's related to causality.
Comment: Thanks Mauricio. It appears much clearer to me now.


Reformat iPhone as USB

Question: Is it possible to erase and reformat an iPhone to be act as a USB? I've seen many apps that can store data and then you can access it, but is it possible to actually reformat the entire iPhone to behave as a USB?
Comment: To what end, really? 32GB iPhone, 500 quid/bucks/shekels. 32GB USB stick, a fiver.
Comment: Tetsujin it's an old iPhone that I just had lying around, so I was curious if I could use it for this purpose.
Comment: A lot of people turn them into iPods. Drop it in the car glovebox, wire into player, never have to remember again ;-) I did that for years before I got a CarPlay system in the car
Answer: Not that I know of, no.  However, there is an app called Documents Pro ($5 US, and definitely worth it) that would do something similar to what you want.  The difference is that it connects via WiFi as a network drive as opposed to connecting via USB.

Reformat iPhone as USB


If Jupiter's day length increased from the current 9 hours to 100 hours, would the weather become more or less violent?

Question: Would average windspeeds increase or decrease if day length increased substantially on Jupiter?
Is windspeed in Jupiter's atmosphere primarily driven by solar energy differentials between night and day side or something else? Would proximity to the sun (2x increase in radiation energy received) have an equal impact on windspeed to a 2x day length change?
Comment: I expect tha the day lengthening process might be quite violent. wheterit lasts for a second or for a million years.
Answer: Jupiter receives 28 times less solar energy than us, and generates about twice as much radiation as it receives, so most of the convection is due to to the latent inner themperature of Jupiter.
If the day lengths were longer, it might forment the convection of the atmosphere, and therefore decrease the wind speed of the high atmosphere by reducing drag.
The winds are the fastest on Saturn because it has less internal heat and less solar radiation, while the surface of the planet is a liquid which exerts very little drag on the atmosphere, and the winds there are 1000 mph.


sundials various Technicalities

Question: when placing a certain type of sundial one needs to point it at true north as apposed to magnetic or the other one.That being said if the meridian line of true north for the location in question is 112 degrees W do you use a compass and adjust 112 degrees W of magnetic north or what?
Answer: What you need to find is the magnetic declination for your location.
A very general world map is here which shows the declination in degrees.
There's an online calculator with various ways to enter your location including by zip code or latitude-longitude and elevation or ellipsoidal height if you have it.
Along your meridian, it ranges from 11°E to 15°E in the contiguous US (lower 48 states) depending on the latitude.
There are plenty of places online to describe how to adjust a compass (I can never remember which way to adjust it!). Here's a USGS site.

sundials various Technicalities


Outline Stroke to Path

Question: I am new to Adobe illustrator. We can change to Outline Stroke from Path. Is it possible reverse. How to change from Outline Stroke to path
Comment: @WELZ - yeah that might be a good option when you don't have access to the original artwork with its strokes. However, it's still a somewhat cumbersome/tedious work around. Personally, where possible, I prefer to work around this problem by planning ahead, by making a copy of artwork before outlining, so if I ever need the strokes back, I always have access to the original to work with.
Comment: Hi. Welcome to GDSE. No. There's no way to reverse the expansion of a stroke to outlines.  Once a stroke is expanded, it becomes a closed path with a fill.  A way to avoid such problems might be to make a copy of your artwork before expanding strokes to outlines.
Comment: @BillyKerr the best solution I've seen was separating the shape into two paths using the blend tool to get the average, I couldn't find it before but here's the link https://graphicdesign.stackexchange.com/a/62480/63979
Answer: Nothing except UNDO or File > Revert to saved can do it perfectly. If they cannot be used you can try an approximation. It's not exact but it can be usable. A common method to try is offset path:

The grey shape is the outlined stroke. The stroke width was 8 mm to get easy to see image for this demo. The red curve is the original path with a narrow stroke, for demo only. We try to recreate it.
Remove the fill, insert a narrow stroke
Decide which side would be less wrong if it's shifted. Here the outer edge is decided to be better. The other side is moved further with the direct selection tool (=move nodes). The ends are kept to have their original orientations, they are only longer
Object > Path > Offset Path > -4mm is applied, the orange curve is the result.
The orange curve is splitted with scissors and the unnecessary part is deleted
The orange curve is stretched to full length with the direct selection tool. Before stretching it can be useful it can be useful to insert with the anchor insertion tool a couple of guard nodes near the end nodes to prevent curvature changes. it happens easily when nodes are moved.

Here's the result placed onto the test curve.It's not perfect, but it can be usable:

As you see the ends are not perfectly sretched. An easy way to improve it is to insert some markers for the estimated stroke ends. A duplicate of curve 2 is excellent. You get a mid-end node by applying Object > Path > Add Anchor points.
Other popular methods for the same:

Split the outline to 2 curves at the ends. Make a 1 step blend and expand it. It works if both halves have approximately the same distribution of nodes. Insert them with the anchor insertion tool to get the halves balanced.
Split the outline to 2 curves at the ends. Give to one of them haw width stroke. Outline it and split the result. One of the halves should be approximately the wanted path.

Both methods can need manual fixes at the ends. 1 is useless if the node distributions are different.
If the outlined stroke was a closed curve, there's no need to worry stroke ends. Only release the compound path and decide do you want to offset the hole shape outwards or the outer shape inwards.

Outline Stroke to Path


Energy required to tilt Earth's axis by 90 degrees?

Question: How much energy would be required to tilt Earth's rotation axis in such a way that what is now poles would be where to equators are relative to Sun and vice versa?
Comment: The poles are points;  the equator is a circle.  You can rotate about 2 perpendicular axes to achieve two different final configurations.  You'll also need to read up on "precession of a gyroscope".  Further, there's a big difference between rotating the axis and changing the axis of rotation. Which do you want?
Answer: Very rough calculation ignoring the orbital angular momentum of the Earth around the sun:
Assuming you are preserving the magnitude $L$ of the spin angular momentum, a $\pi/2$ flip of the earth will result in an angular momentum change of $\sqrt{2} L$. The magnitude of the torque necessary to achieve this is time $\Delta t$ is $$\Delta \tau = \frac{\sqrt{2} L}{\Delta t}.$$ The work necessary is $$\Delta W = \Delta \tau \Delta \theta = \frac{\sqrt{2} L}{\Delta t} \cdot \frac{\pi}{2} = \frac{L\pi}{\sqrt{2}\Delta t}. $$ Further assuming the earth is a perfect sphere rotating around an axis connecting its poles, $L \approx 7 \times 10^{33} \, \mathrm{kg m/s}$ (see this). This means the work done as a function of the total time taken to flip the earth is
$$\Delta W = \frac{1.55 \times 10^{34}}{\Delta t}.$$ You can put whatever value of $\Delta t$ in there; in particular assume you can rotate the earth in $1$ second. In that case,
$$\Delta W = 1.55 \times 10^{34} \, \mathrm{J},$$ which is a lot of energy.
Comment: Note that Earth's [gravitational binding energy](https://en.wikipedia.org/wiki/Gravitational_binding_energy) is $2.49 \times 10^{32}\,\mathrm J$, so you need to be careful how you twist it. ;)
Comment: @PM2Ring  Guess we're better off building **Earth Engines** to stop the rotation over a couple hundred years, then rotate the other axis, then start up rotation again
Comment: precarious situation - more than expected , I am after buying some land in Antarctica from this fellow and trying to optimize my return on investment

Energy required to tilt Earth’s axis by 90 degrees?


Converting negative values from FROM_UNIXTIME

Question: I have been trying to convert Date of birth from my DB into DATE FORMat but i am facing the problem of there are some negative values in DOB fields which when i check from online FROM_UNIXTIME calclator then it give different result and if i check it with FROM_UNIXTIME(-957632400) then it always returns NULL for negative values . KIndly let me know how can i get date format from such UNIX format like from -957632400
Answer: We can do this instead:
FROM_UNIXTIME(0) + INTERVAL -957632400 SECOND

The FROM_UNIXTIME function is limited by the allowable range for the TIMESTAMP datatype, which is the standard 32-bit unsigned int range 1970-01-01 thru 2038-01-something. Other software has been updated to support 64-bit signed integers, but MySQL doesn't yet provide that functionality (at least not in 5.1.x).
The workaround in MySQL is avoid using the TIMESTAMP datatype and using the DATETIME datatype instead, when we need a larger range (e.g. dates before Jan 1, 1970).
We can use the DATE_ADD function to subtract seconds from Jan 1, 1970, like this:
SELECT DATE_ADD('1970-01-01 00:00:00',INTERVAL -957632400 SECOND)

N.B. You will probably need to account for timezone "offsets" from UTC in doing those types of calculations. MySQL is going to interpret DATETIME values as being specified in the time_zone setting of the current MySQL session, rather than UTC (time_zone = '+00:00')

FOLLOWUP:
Q:  Okay, Means if we select dates below '1970-01-01 00:00:00' then the negative value saves in the db else it would be positive. Right? – soft genic
A:  Uhhh, no. If you select date/datetime values before Jan 1, 1970, MySQL will return DATE or DATETIME values before Jan 1, 1970. If you store DATE or DATETIME values before Jan 1, 1970, then MySQL will store DATE or DATETIME value before Jan 1, 1970, within the allowable range supported by those datatypes. (something like 0001-01-01 thru 9999 ?)
If you need to store really really big positive and negative integers in the database, you would likely store those in a column defined as BIGINT.
The internal representation of a DATE column requires 3-bytes of storage, and DATETIME requires 8-bytes of storage (up to MySQL version 5.6.4. The internal representation and storage of DATE and DATETIME values changed in 5.6.4)
So no, MySQL does not store date values before 1970 as "negative integers".
If you think about it a bit, MySQL is free to implement whatever storage mechanism they want. (And each storage engine is free to serialize that representation to disk however it wants.)
Why 3 bytes for a date?
One option MySQL has (and I'm not representing that this is the way it is done) could be to break up the date into it's year month and day components.
The representation of integer values in the range  - requires -

0 - 9999 - 14 bits
0 - 12 -  4 bits
0 - 31 -  5 bits

That's a total of 23 bits, which happens to handily fits into 3 bytes.  This just demonstrates that it's not necessary for MySQL to represent date values before Jan 1. 1970 as negative integers, so we shouldn't make the assumption that it does. (But we'd really only be concerned with this level of detail if we were working on a storage engine for MySQL.)
Comment: A simple clarification for users that want a quick answer:
Instead of
    "FROM_UNIXTIME(data)"
use
    "DATE_ADD(FROM_UNIXTIME(0), INTERVAL + data SECOND)"
Comment: Okay, Means if we select dates below `1970-01-01 00:00:00` then the negative value saves in the db else it would be positive. Right?
Comment: kindly check this question see if you can help http://stackoverflow.com/questions/11588010/record-insertion-between-two-tables-selecting-when-to-calculate-age
Answer: From DATETIME to unix timestamp:
SELECT  TIMESTAMPDIFF(SECOND, FROM_UNIXTIME(0), '1956-12-24 01:06:49');
From timestamp to DATETIME:
SELECT  DATE_ADD(convert_tz(FROM_UNIXTIME(0), @@session.time_zone,'+00:00'), INTERVAL -410914391 SECOND);


Not Rendering Wood Texture on Material

Question: I have been attempting to make a wooden plank. I have expanded it, colored it, and merged it with a Metaball structure. However, when I detach it from all other structures and then attempt to follow the way the WikiBooks (https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Procedural_Textures) adds the Wood texture, the texture does not render. I have attempted to do the same with a random cube on a new file, and still, it does not render. I have not assigned the texture any colors yet. What may be happening?
Comment: That wikibook is for an old version of blender (2.70) and textures have changed since then.  Could that be your problem?
Comment: Ah! I didn't realize. How can you add the texture on 2.9?
Answer: If you're using a newer version of Blender, the reason you don't see anything is that you're not actually editing the texture on the object.  This wiki is definitely out of date for newer versions.
In order to use a texture on the object, the "Base Color" of your material would need to point to a texture object of some sort, but if you click on the circle next to Base Color, you can see there is no "Wood" type of texture:

That's what you'd need to be able to follow those instructions.
Or, you'd need a way for Blender to allow you to connect that texture node to the color of the Material.  Unfortunately this doesn't exist in this way in current Blender.  In fact I would assume if you look at your Texture panel, you'll see it says "Brush" at the top, like this:

That's because it's actually a Brush for texture painting, not a texture that can be assigned to a shader.  The 'Texture' panel doesn't actually let you create a Texture as such.  You can create an image by setting your base color to Image Texture, and then choosing 'New' here:

...but it'll be blank. You can't create a 'Wood' texture. In fact, in current Blender there is no 'Wood' type of shader at all so you need to create your own.
I hope this wasn't too confusing; after all the interface definitely is in this case.
There's no simple way to duplicate that tutorial, unfortunately.

Not Rendering Wood Texture on Material


Does anyone have any tips on how to do pseudo modulation?

Question: Does anyone have any tips on how to do pseudo modulation (fake modulation)?
https://vimeo.com/1934047

Those two videos and the song "moon river" is the most i seen on it.
Does anybody have any more constructive tips on how to do it?
Answer: The underlying theory is that any key you start from is a modal key in every other key. When you start playing, the choice of notes leads the audience's ear towards a particular key, not necessarily consciously, and that key has psychological implications which keys the audience to particular emotional palettes. However, because the chords do not fill the scale, each interval used actually filled only slightly reduces that choice - this is why dodecacophony is so psychologically distressing to someone lacking the auditory education to handle it. Particular intervals - notably the seventh, the "leading note", but also the blues diminished sixth and some others - leave the ear seeking resolution, not necessarily in the key you're actually in. The tease can be the use of a passing note to hint at an intention which never comes to fruition.
What's actually happening is that the hint takes the audience into the other key, but the modulation is a two-way street and no sooner does the performer put his nose round the corner than he realises it's not where he intended to go and comes back again, leaving the audience rushing to catch up having seen a world they're not being taken into.
Answer: In the video, the instructor speaks of such a fake modulation "written into Rainy Day." Do you have the score? Take a look at pieces of music that do what you want and analyze. See what they do.
It looks like we're mostly looking at chromatic thirds ("going to" Ab major in F major), but instead of staying there, do another one to get back to the original. For instance, in F, tonicize Ab, then do another chromatic third to C7 which goes back to F naturally. It will "feel" like you've gone a long way, but of course, you're back where you started.
Another example (from the video which you posted) is (in F again) tonicize Ab, and even play V/Ab (Eb7), then simply continue in F. It's not as jarring as it ... sounds.
Answer: Unfortunately, I can't watch the video right now, but I do know the main melody of Moon River. So, looking up pseudo-modulation and a lead sheet, I believe I see what you're referring to. For the most part, this pseudo-modulation is taking advantage of the circle of fifths and ii-V-I cadences to lead the ear temporarily astray for intrigue. It starts off in C major and is simple enough. Then we get our first iio-V-i, the minor equivalent of ii-V-I, right before the first ending. Bm7♭5-E7-Am7 brings us to A minor, just the relative minor. Again, nothing crazy.
Then, at the beginning of the first ending, we have an odd C7 chord. The C is usually just a major or major 7 chord in A minor, but the dominant seventh and the Fmaj7 chord right after it make it function as a dominant chord. So C7-Fmaj7 and now we're in F major. But that only lasts for one chord, as the Bb, which is normally the 4th of F major, is also a dominant chord is leading a halfstep down right back into A minor with the Am7. The Bb7 was acting as a tritone substitution.
We don't stay in A minor for long, though. The next three chords are a iio-V-i, except the V chord is substituted with its tritone partner, F7. So the F♯m7♭5 acts as the iio chord, the F7 acts as the v chord, and Em is the new tonic. Except, oops, your ear was wrong because now that Em7 is acting as the ii chord for the next cadence. Em7 is the ii, A7 is the V, and Dm7 is the i. And again, your ear has been deceived, as the Dm7 was actually the ii chord for a ii-V-I right back into C where we started.
Then, everything is normal or repeats old concepts until we get to the last few chords, starting with C♭. Honestly, without being able to hear the song, I'm not sure what's going on here. It looks like just a bunch of chromatic motion downwards back to Cmaj7. Regardless, it's quite amazing because although all of these quick cadences should be leading into other keys, they're really just dancing around C major and A minor. Most of the chords are just slight alterations of chords from our main keys and our ear is just led by the chain of fourths. This is rather common in jazz and has a wonderful effect. I'd never heard it referring to as pseudo-modulation before, though. Makes sense.


How should I read "Julius Wilhelm Richard Dedekind" in German?

Question: How should I read "Julius Wilhelm Richard Dedekind" in German? Please use the International Phonetic Alphabet (IPA) for German to show how to read it.
Comment: @RDBury English speakers usually read it as [ˈdɪdkɪnd] which is different from what Hubert Schölnast gives as follows.
Comment: Richard Dedekind was a famous mathematician so I've heard the name said a number of times, at least by English speaking mathematicians. I don't remember ever hearing the name pronounced differently than you'd expect as an English speaker. The pronunciation of "Richard", however, is very different in German compared to English.
Comment: Yes, there are some minor difference owing to the German "accent". In particular a 'd' at the end of word in German sounds much like a 't' in English. Different languages have different sounds, and while sounds can be similar between languages, they are rarely exactly the same. IPA is really just an approximation, so it's a matter of how detailed you want to get. We can't teach you to speak like a native German speaker, and it takes a lot of practice just come close.
Answer: This name is pronounced [ˈdeːdəˌkɪnt].
His whole name is "Julius Wilhelm Richard Dedekind", but he became known as "Richard Dedekind" which is pronounced [ˈʁɪçaʁt ˈdeːdəˌkɪnt]

Julius =  [ˈjuːli̯ʊs]
Wilhelm = [ˈvɪlhɛlm]
Richard = [ˈʁɪçaʁt]
Dedekind = [ˈdeːdəˌkɪnt]

(In souther regions of Germany and even more in Austria you will also hear [ˈʁɪçaʁd] and [ˈdeːdəˌkɪnd], because people in these regions use slightly different pronunciation rules, but Dedekind was born in Braunschweig in Lower Saxony which is in the north of Germany. So only the versions [ˈʁɪçaʁt] and [ˈdeːdəˌkɪnt] are correct.)
Comment: @M.Logic: **No!** It's [ˈdeːdəˌkɪnt] everywhere. No matter if your native language is Arabic, Japanese, Suaheli, Navaho, English or German. Maybe you have troubles to pronounce it correctly if you're not a German native speaker, but still only [ˈdeːdəˌkɪnt] is correct. [ˈdeɪdəˌkɪnt] is not. I think what you mean, is that the long vowel [eː] does not exist in English words. ([e] exists only as part of a diphthong in English, like ...
Comment: ... in "break" = [bɹeɪk/]) And [θ] does not exist in German. So what? The only correct pronunciation of "Smith" is still [smɪθ], also for German native speakers, which causes troubles to many of us (many of us say [smɪs]), but it doesn't change how this name is pronounced correctly. ([smɪs] is wrong. It's as wrong as [ˈdeɪdəˌkɪnt].) And also "Dedekind" is still correctly pronounced [ˈdeːdəˌkɪnt], no matter what your native language is.
Comment: The letter I in IPA stands for "International" (IPA = [International Phonetic Alphabet](https://en.wikipedia.org/wiki/International_Phonetic_Alphabet)). There is not a German or an English version of this Alphabet. That's the point of having an international phonetic alphabet. It is explained here: https://en.wikipedia.org/wiki/Help:IPA
Comment: "Richard" is in practice more likely to be pronounced [ˈʁəçat] in standard and northern German, [ˈrɪçət] in some southern dialects. Only very deliberate pronunciation will bring out the second rhotic.
Comment: This is in [IPA for German](https://en.wikipedia.org/wiki/Help:IPA/Standard_German) while not IPA for English?
Comment: So [ˈdeːdəˌkɪnt] in IPA for German should be close to [ˈdeɪdəˌkɪnt] in IPA for English.
Comment: I know your meaning. Exactly speaking, [ˈdeːdəˌkɪnt] is correct, and [ˈdeɪdəˌkɪnt] is not accurate, but some other people which are not German can possibly learn to speak it from English possibly. So I think [ˈdeɪdəˌkɪnt] is very close.


How can I measure calcium levels in my blood at home?

Question: I need to check my vitamin D levels regularly for my disease. It doesn't seem possible to measure at home, but measuring calcium in the blood may be more achievable since they are directly correlated. But then how can I do it?
Answer: You should not use calcium as an indirect means to evaluate your vitamin D status. While both are metabolically connected different mechanisms are involved meaning that there is not a one directional correlation across time, and many other things, unrelated to vitamin D, affect blood calcium levels as well.
In the short run, all else kept equal (which is a culprit), a higher vitamin D status will lead to a greater portion of a dietary dose of calcium to be absorbed. However, this will also lead to increased bone formation, and soft tissue mineralization, which has the opposite effect on blood calcium levels in the short to medium term.
With time and resources you could probably develop a model for a very controlled process to measure your vitamin D status through your blood calcium levels, but it wouldn't be practical for people to use in general, and it would also cost you personally much more time and resources than just getting a vitamin D lab test every 3 months for the next couple of years.
While blood levels of vitamin D may fluctuate in the short term, your overall vitamin D status fluctuates slowly (which is due to the fact that your body fat acts as a storage buffer for it). That and the fact that is has become a very routine test makes it affordable to monitor via routine lab testing.
If you develop a proper habit to expose a greater part of your bare skin to sunlight once every 7-10 days, and have a stable diet, you can just use initial testing to confirm the effectiveness of that habit and then save even more money by not testing for your vitamin D levels at all.
Your body'd capacity to efficiently produce vitamin D will slightly decrease over time as you get older, but that happens only very slowly, so you can consider the execution of whatever habit you have developed to be a good way to predict a good vitamin D status.


Where is the list of launcher-locked .desktop entries?

Question: Where does Unity (under 16.04) keep its list of desktop files for the Launcher. Not "where are .desktop files found?" but where are just the ones that Unity has right now in my launcher. One of them is placeholder "?" for an appimage executable, and I want to tweak that entry to point to an appropriate icon. The app doesn't have an existing .desktop entry yet in /usr/share/application or my .local stash, so I want to tweak the placeholder that Unity created for it rather than hand-roll one.
Answer: Found it! A little better searching and some testing found the answer.  It's kept in gsettings, and I pulled the list using
gsettings get com.canonical.Unity.Launcher favorites

And then a simple
find -iname <foo.desktop>

Showed me where it made the placeholder.


How to run arbitrary code when django shell starts?

Question: This question: Automatically import models on Django shell launch has answers explaining how to import models upon start by using shell_plus, but no answer about how to run code in general.
But is there an easy way to just run a python script?
python manage.py shell [or shell_plus] --run=script.py

Would just run the script as if you'd typed the whole thing in as the shell started.
I realize that you can import things in the shell, but then they're stuck within a namespace.
I would think ipython should have a way to run a script, and then import its locals() into the toplevel namespace.  In that case you could just do %magic script.py and we'd be down to just one step, which would be good.
Changing the way you start the shell should be fine - the main goal is to just be able to create a file that's run on startup of the shell.
Answer: You can create your own custom command just like shell_plus has done: see the source of the shell_plus command to see how. In that code you can specify and run the file that needs to be executed before starting the shell. Also useful is Django's documentation on creating custom commands.
Answer: You can try to use environment variable PYTHONSTARTUP.
Also try django-extensions: django-extensions
See django-extensions/management/commands/shell_plus.py command.
From source code of this command I see that it respects PYTHONSTARTUP env variable.
Comment: the problem is that I might not want it to be run for all shells - I use ipython for things other than django!  and shell_plus only loads models.
Answer: shell_plus uses a limited form of IPython which doesn't process its startup & configuration, which defeats most normal attempts to run things at django+ipython shell startup.  You can switch it to use the full version which will solve most problems.
Modify django_extensions/management/commands/shell_plus.py
remove:
embed(user_ns=imported_objects)

and replace it with:
from IPython import start_ipython
start_ipython(argv=[], user_ns=imported_objects)

Then your python code in the startup directories will be loaded.
Answer: Not sure if there's a flag you can use, but if you have ipython installed it should be as simple as:
ipython
Then when you're in the prompt:
run script.py
Then:
run manage.py shell
Answer: It seems that the easiest way is to run
cat myscript.py | awx-manage shell
For reference, see https://github.com/ansible/awx-operator/blob/7d2d1b3c5e3766966bfec0f9f58037f654b93b59/roles/installer/tasks/initialize_django.yml#L21-L24


What is WIT used for?

Question: What does the WIT parameter do? How is it calculated?
Answer: The WIT is used for calculating bonus resource gain when operating a major module with the Operate skill. To use this skill after you've learned it you have to stay in the same room as your selected major module for one turn, and after that, until you leave the room, you can enjoy bonus resources equal to half the character's WIT from the module.
For other modules it does different things:
Shop (with Merchant): One tenth of total wit rounded up is added to the Dust generation every turn.
Generator: Each point of wit adds 0.5% chance to find Dust on the level.
LAN: Each point of wit adds 1.2% percent defense to all modules (major and minor) on the level.
Tactical HUD: Each point of wit adds 1.2% percent attack power to heroes on the level. When upgraded to Tactical HUD IV, the bonus increases to 1.8% percent.
source
Higher WIT will also allow you to repair modules faster with the Repair skill.
As to how it's calculated - as any other stat. Each character has his/her/it stat growth, and you can get bonus WIT from items or skills.
Comment: Do I understand correctly that Wit is useless until/unless you have the Operate and/or Repair skills?
Comment: @PhasmaFelis Yes, that is correct. Note that there are items that will grant these skills, so it doesn't necessarily have to come from a hero.

What is WIT used for?


Tiagra 4700 2x10 vs 105 R7000 2x11 for Gravel Bike

Question: I'm putting together a gravel bike from parts. It will be for mechanical brakes -- cantilever at first and maybe mechanical disc later. I will be buying new shifters, derailleurs, cassette, and chain. The question: Is there a good reason to consider Tiagra 4700 2x10 instead of 105 R7000 2x11? Both offer clutch rear derailleur options (GRX400 for the Tiagra). Cassette options are good for both, 11-32 or 11-34 for Tiagra, and 11-34 for 105. A strange thing to me is that there is very little difference in price.
Comment: Do you have a particular reason to not go directly to disc brakes? Asking because large tires are appreciated in gravel bikes, and rim brakes will be very constraining on that matter. Also, going to disc directly will allow you to install GRX components, are more suited for gravel riding.
Comment: In answer to the above comments ... (1) I am using very small chainrings, not groupset -- 40/24 or 42/26; I have experience doing this on other builds. The small front / large rear combo will thus have a very low gear ratio of 0.8 or less.  (2) I am starting with rim brake wheels and Tektro cantilever brakes that I have in order to make best use of my parts inventory; I already have a frame and fork that accommodate both cantilever and disc brakes for QR wheels.
Comment: Going for disc brakes straight also means you don't need brake mounts for both.
Comment: With the 2x11 you can have closer gear spacing (smaller steps between gears). Apart from that there probably really isn't much difference. Can't you go for a GRX groupset with smaller chainrings? The 50/34t chainrings on the Tiagra and 105 make steep climbs really hard.
Comment: @Renaud Cantilevers work just fine with large tires. V brakes would work too, but the awful shifter/lever combinations today don't allow you to choose separately a shifter for the desired number of gears, and a lever for the desired pull ratio, independently from each other.
Answer: There are several benefits of Tiagra:

Cheaper initial investment, yet still probably good enough for actually using it regularly
Cheaper wear parts
Thicker chain and sprockets so with similar materials you get more wear life out of the wear parts, all else being equal (although more expensive 11-speed chains and cassettes could obviously use better materials, so not all else is necessarily equal if you are comparing for example Dura-Ace 11sp with Tiagra 10sp)
Larger jumps in cassette, meaning you have to do fewer gearshifts to get the desired change -- today, most systems have way too densely spaced gears
11-speed cassettes may not be compatible with all Shimano freehub style hubs since you need special 11-speed hubs, 10-speed cassettes on the other hand are with 8/9/10 speed and also 11-speed hubs with a spacer (unless you are considering some really old freehub like 7-speed) -- you didn't mention what hub you have but it may force you to use 10-speed cassettes

Also something to consider:

With Tiagra 4700 the rear derailleur pull ratio is the same 11-speeds, so when it will no longer be possible to buy 10-speed parts you can still buy rear derailleurs that are compatible with your system, and also the pull ratio of Tiagra 4700 and 11-speed systems allows smoother shifting than the old pull ratio, even if you run full-length housing
With 11-34 tooth cassette, the 11-speed system doesn't add anything really apart from way too densely spaced gearing, since the low and high gears are the same
Comment: define "too densely spaced"?
Comment: I agree with @PaulH, this is mostly a reasonable answer apart from the contention that 11s systems are too closely spaced. I find this assertion to be odd. 9s and 10s drivetrains generally were very much more closely spaced when they were introduced, e.g. the default cassette was 12-23 or 12-25.


Can't sign-in Xbox Windows 8.1 - Error 0xc00d11cd (0x80004005)

Question: When I try to sign-in in Xbox games in Windows 8.1, I write my password and when I click ok, it returns the following error:

Xbox service is not available at the moment
  Try again. If the problem stills visit www.xbox.com/support for help
  ...
  0xc00d11cd (0x80004005)

I already verified Xbox status at https://support.xbox.com/en-US/xbox-live-status but it is "up and running"
Already reinstalled Windows 8.1 and the problem stills
How can I fix this error?

Sorry if i'm misssing anything, i'm new user to Windows, I was using Mac OSX and sorry for my bad english...
Answer: After hearing of changes to my contract with Xbox, I solved this problem by logging into http://www.xbox.com/support with my account, then accepted the contract's modifications.  (I was unable to find the latest updates!)
Answer: After I instaled all updates with Windows Update the problem solved itself.


Calculating the viewing angle of a circle

Question: A 10 foot  circle appears as an ellipse with minor axis of 7 feet and major axis of 10 feet. How do you calculate the viewing angle of the circle to see it an this size ellipse?
Answer: In the below figure, your eye is far off in the $-x$ direction.  The major axis of the visible ellipse is perpendicular to the page.  You have a right triangle.
Answer: Consider this analogy.
A coin is held parallel to the plane of the eye. The diameter is observed as equally along x & y direction.
Now, assume the wall to be the plane of the eye. Using a torch if light beamed on the coin the shadow is a circle representing the diameter of the coin.
If the coin is tilted towards or away from the light, its shadow appears like an ellipse. The ratio of the shorter axis to the diameter represents the cosine of the angle at which the coin is tilted.
In this case cos-inv(7/10) is the angle of the tilt = 45.57 degrees


Timely block times on private network

Question: I've been working on building and testing a private ethereum network using geth and commodity AWS hardware. I'm curious if it's realistic to expect 14s block times in this case? What I see is very fast block times at the beginning of a new chain, but then it slows to around 21s block times within the first 20,000 blocks.
Comment: Just digging up this old thread: Have you made/Did you make any code changes in Geth?
Answer: This turned out to be a resource problem. Once I allowed geth to use multiple minerthreads, the block times hit a more typical average of around 14-15 seconds.

Timely block times on private network


Book about a man that turns into a raven and is shot and killed at the end

Question: A romance about a man that turns into a raven. At the end the raven is shot and killed. I want to know the author or book title please. I think the author name started with a B. I think theres a sequel.
Comment: Hi there! That's some info already, but could you please take a look at [these guidelines on story-ID](https://scifi.meta.stackexchange.com/a/9337/98028), see if they trigger any more memories you could [edit] in? Perhaps the most important -  when would it have been published?
Comment: I tried to add more to my question.
Comment: If there's a sequel, does the man somehow survive his death then, maybe being reborn as a man?
Comment: Why is a raven like a writing-desk? Because there is a B in both.
Answer: The Chinese folktale of "The Man Who Was Changed Into a Crow" matches on almost all points.

MR. YU JUNG was a Hu-nan man. The person who told me his story did not recollect from what department or district he came. His family was very poor; and once, when returning home after failure at the examination, he ran quite out of funds. Being ashamed to beg, and feeling uncomfortably hungry, he turned to rest awhile in the Wu Wang temple, where he poured out all his sorrows at the feet of the God. His prayers over, he was about to lie down in the outer porch, when suddenly a man took him and led him into the presence of Wu Wang; and then, falling on his knees, said, "Your Majesty, there is a vacancy among the black-robes; the appointment might be bestowed on this man." The King assented, and Yu received a suit of black clothes; and when he had put these on he was changed into a crow, and flew away. Outside he saw a number of fellow-crows collected together, and immediately joined them, settling with them on the masts of the boats, and imitating them in catching and eating the meat or cakes which the passengers and boatmen on board threw up to them in the air. In a little while he was no longer hungry, and, soaring aloft, alighted on the top of a tree quite satisfied with his change of condition. Two or three days passed, and the King, now pitying his solitary state, provided him with a very elegant mate, whose name was Chu-ch'ing, and who took every opportunity of warning him when he exposed himself too much in search of food. However, he did not pay much attention to this, and one day a soldier shot him in the breast with a cross-bow; but luckily Chu-ch'ing got away with him in her beak, and he was not captured. This enraged the other crows very much, and with their wings they flapped the water into such big waves that all the boats were upset. Chu-ch'ing now procured food and fed her husband; but his wound was a severe one, and by the end of the day he was dead at which moment he waked, as it were, from a dream, and found himself lying in the temple.

The tale goes on to have him be reunited with Chu-ch'ing, who had become a river spirit, and their son, Han-ch'an. There was a Japanese adaptation of it named "Blue Bamboo" in the book of stories by the same title, written by Osamu Dezai. Lastly, Boria Sax described a translation where the protagonist was transformed into a raven in Crow from Strange Stories from a Chinese Studio (archive.org link).
I found the original mention of the story by searching for novel Man "turned into a Raven" shot
Comment: @dannymcg: Nope. He becomes a raven, meets the girl raven, had a son, gets shot, wakes up human again, meets girl raven again who's actually a minor goddess, gets turned into a raven again.
Comment: Why is it a romance? Does he meet a girl but then turns into a raven?


Micro controller serial communication question

Question: Im relatively new to micros and have a conundrum.  My senior project  involves using a touch screen and xbee modules for wireless communication.  My question is, since both of them require serial communication, should I find a micro that has 2 serial ports, or is it possible to have both of them connected to the same serial port and select which one to communicate with?
Comment: That depends on how much time and money you're willing to throw at the problem.
Answer: You can't, in general, connect them to a single serial port. You'll need a microcontroller with (at least) two serial ports.
Sometimes, if you're trying to really minimise the cost of the microcontroller, you can implement a seral port using GPIO pins and I/O instructions. This can be very effective for a transmit-only serial port. But I would not recommend it for a project like this.
Answer: Logic level serial communication doesn't normally support multiple devices. You need two UARTs.
The SPI bus supporters multiple devices which are each selected using a chip select (CS) line.
The I2C bus supports multiple devices which are selected using inband protocol addressing.


How to get why an app crashed?

Question: I regularly obtain the infamously unhelpful "unfortunately crappyApp has stopped working". How to figure out what actually went wrong? I guess there's a stack trace somewhere, though ideally I'd like to modify the unhelpful message itself if that is possible on a rooted device.
Comment: For a starter, we have the [troubleshooting tag-wiki](http://android.stackexchange.com/tags/troubleshooting/info) ;)
Answer: You can simply see the crash stack trace after any crash happens.
Use ADB command below,
adb logcat -b crash #default
adb -d logcat -b crash #show from device when multiple device
adb -s logcat -b crash #show from simulator when multiple device

Answer: There are multiple ways to obtain useful information. But as Dan pointed out, on-device solutions will require root (starting with JellyBean) – and off-device solutions ADB:

adb logcat was already described in Dan's answer. For more details, you can see our logging tag-wiki.
adb bugreport > report.txt gives very detailed information, including details from the dumpsys, dumpstate, and logcat tools. Several tools for easier analysis of its output can be found e.g. in the answers to Better method of viewing "adb bugreport" output? on our sister-site.
there are tools to be installed on your computer which utilize the above (or at least parts of it), like QtADB (for Linux, Mac, and Windows)
there are Android apps like Bug Reporter; but as pointed out, most of them will require root. Bug Report Reader however claims to read system logs (logcat, dumpsys, dmesg, top and much more) on your device, without root, so that might be worth trying.
Answer: In most cases, if USB debugging is turned on, you can use adb logcat to see the exception output. This usually includes a stack trace, but that's not often useful unless you have the app's source code. All the same, the developer of the app will probably be grateful if you include it in any bug report.
Comment: Thanks, I'd prefer a native solution directly on the device if possible. good point about the usefulness, doesn't the trace at least include sensibly named java exceptions? or does dalvik obfuscate them?
Comment: good point about that exception :/ since I rooted my device anyway, I was hoping for a more comfortable way than logcat, though that's better than nothing...
Comment: There are apps to read the log from the device (search Google Play for *logcat*), but in Jelly Bean and later, apps can't read each other's logs, so you might need to root your device to do this. The trace includes Java exception names, but `NullPointerException` doesn't really tell you a lot unless you're the app developer.
Answer: Read the files under /data/anr/ which stands for "apps not responding". I use adb shell cat /data/anr/$FILE
There will be one for every app which force closes, or is not responding for some reason.
Comment: When looking at /data/anr/ in a root file explorer, there's only a single traces.txt which was modified three days ago (even though an app crashed today), and it appears to contain only system crashes, not app crashes. Is there another way too see those app backtraces?

How to get why an app crashed?


Clearance and creepage for AC Optocoupler for 230V line detection

Question:
I was wondering how I need to handle clearance and creepage in this scenario.
It's AC mains line detection circuit.
I need to achieve around 2.5mm creepage.
Comment: Why do you have a problem achieving this requirement?
Comment: I was wondering if the sum of the creepage between the pads of R2 and the creepage between the pads of U2 need to be bigger as 2.5 aswell. Could the voltage arc across the resistor? Is there any rule for that?
Comment: Rules depend on what you are trying to aim for in terms of product certification.
Answer: I also posted the question on reddit and got the answer there:

So a few things before the actual answer:
What's the mains voltage? 2.5mm sounds like 240V if I'm not mistaken.
  (correct)
In situations like this, you can increase creepage distance by adding
  a board cutout (slot) between the pins. You can also reduce creepage
  requirements by adding a conformal coating.
It would be weird if the datasheet of a component intended for AC
  mains use violated clearance/creepage requirements, and made no
  mention of the above, right? That usually means something else is
  going on.
In this case (real answer now) you are looking in the wrong place.
  Because you have two LEDs that are anti-parallel, one of them will
  always be on. That means the voltage between the pins is not
  120/240/whatever but just the forward voltage drop of the LED. You
  don't have mains voltage between the pins, you have 1.4V (per the
  datasheet). So that spacing is perfectly fine.
What you do need to consider is that nearly all of that voltage is
  actually dropped across R2. That is where you need to worry about
  creepage, and in this case the two SMT pads of that resistor do look
  way too close together. I also do not see any current limiting,
  meaning that if that resistor fails short or a short otherwise
  develops, you're in for a bad time.
In this case just choose a larger resistor package to maintain the
  requisite spacing requirements. You can also add a slot between the
  resistor pads to improve the situation slightly, but you'll need to
  upsize either way as the resistor body itself still provides a bridge.
220k is also quite a large value, make sure it's enough to actually
  turn the output on sufficiently. That's 1mA at 240 which is probably
  enough but double check. And of course power rating and all that which
  you're already aware of.

Credit: u/happyhappypeelpeel


Make a form wider in size in Cognito Forms

Question: I have created a registration form but how do you make it wider in it's size? It appears narrow on my website.
Answer: I am a developer for Cognito Forms. Our forms are built to be responsive, because of this we set our form to take up 100% of the container width they are placed in when embedded. So if you have applied a specific size to the place on your page where the form is embedded, it will only take up that amount of space. We also try to use minimal <code>!important</code> tags in our CSS so any styles you have applied to your website will also be applied to your form.
We would be happy to help you look into why the form is not using the entire width provided if you would like to submit a support ticket.
Comment: Yes, the transparent background was exactly what helped my size issue, which was more due to the set layout theme of the website I was using. Nicholas was very helpful through the whole process, even doing a demo of a wider form on my site to see if I liked it. I had several correspondence over a few days time with him and he always answered my question the same day if not within the hour! Never have I had support like that!! Will for sure be using Cognito Forms for my other websites!
Comment: Just want to add that the solution we recommended to Kellie in this case was to set the background color of her form to transparent so it would blend in seamlessly with her website.  This was exactly what she needed.  We had already decided to default backgrounds to transparent for new forms in our next release for precisely this reason.


What date/rank is this Italian uniform?

Question:
Believed to be from the 1920's from the Turkish or WW1
Any insights into dates, and rank would be great
Answer: This is a 1909 model uniform that is likely from before 1924 when pockets would have been added. Italian uniforms after 1915 bore their rank insignia on sleeves and on the hat, neither of which are present in the image, so we cannot say what this man's rank was.
The collar patch (mostrine) indicated the regiment, but unfortunately the color was a significant component of the symbol and that, of course, is also missing. By the three horizontal stripes over a very dark background, we can narrow him down to one of these infantry regiments:

Valtellina

Pisa

Ancona (most likely, given the shade of the stripes)

Pinerolo and Palermo are possible but less likely as red or blue would not show up so bright.

However, the collar tabs on your image look very strange, possibly due to the warping of the round glass. Is it possible to get a clearer photo?

What date/rank is this Italian uniform?


Installing PCRE 32bit on RHEL 5 - resolving dependency for apache 2.4 install

Question: I need to install Apache 2.4 32bit version on RHEL 5. I am not installing 64bit apache because the application running on the RHEL5 machine needs apache 32bit (or that's what I thinks because of the past behavior).
I receive "could not read symbols" while make which is probably due to pcre libs are of ELF 64bit when the installation expects it to be of ELF 32bit
**/usr/local/lib/libpcre.so: could not read symbols: File in wrong format**
collect2: ld returned 1 exit status
make[1]: *** [httpd] Error 1
make[1]: Leaving directory `/opt/myapp/httpd-2.4.7'
make: *** [all-recursive] Error 1

The configure for Apache 2.4 is run as:
CFLAGS="-m32"; export CFLAGS
LDFLAGS="-m32"; export LDFLAGS
"./configure" \
"--prefix=/opt/myapp/apache2.4" \
"--with-mpm=worker" \
"--enable-static-support" \
"--enable-ssl=static" \
"--enable-modules=most" \
"--disable-authndbd" \
"--disable-authn-dbm" \
"--disable-dbd" \
"--enable-static-logresolve" \
"--enable-static-rotatelogs" \
"--enable-proxy=static" \
"--enable-proxyconnect=static" \
"--enable-proxy-ftp=static" \
"--enable-proxy-http=static" \
"--enable-rewrite=static" \
"--enable-so=static" \
"--with-ssl=/opt/myapp/apache2.4/openssl" \
"--host=x86_32-unknown-linux-gnu" \
"host_alias=x86_32-unknown-linux-gnu" \
"CFLAGS=-m32" \
"LDFLAGS=-m32" \
"--with-included-apr" \
"--with-pcre=/usr/local" \
"$@"

I have installed PCRE without any error using:
./configure --prefix=/usr/local --enable-pcre32

When I do pcretest it get this (Compiled with 8-bit support?):
$ /usr/local/bin/pcretest -C
PCRE version 8.33 2013-05-28
Compiled with
  8-bit support
  No UTF-8 support
  No Unicode properties support
  No just-in-time compiler support
  Newline sequence is LF
  \R matches all Unicode newlines
  Internal link size = 2
  POSIX malloc threshold = 10
  Default match limit = 10000000
  Default recursion depth limit = 10000000
  Match recursion uses stack

But when I check the libs created (which are supposed to support 32bit apps) I get ELF 64bit.
$ file libpcre32.so.0.0.1
libpcre32.so.0.0.1: **ELF 64-bit** LSB shared object, AMD x86-64, version 1 (SYSV), not stripped

Answer: Your --enable_pcre32 configure option refers to the 32 bit option of pcre itself (can be enabled to handle 16 bit or 32 bit versions of regex - presumably for Unicode stuff?)
Try building pcre with the -m32 options you used on your Apache configure.
Comment: Or alternatively grab a precompiled one: [link](http://pkgs.org/centos-5/utter-ramblings-i386/pcre-8.13-1.jason.2.i386.rpm.html)


How are watermarks typically used in images?

Question: In terms of visible watermarks, what types and quantities are commonly used on an image?
Comment: Hi there. Can you flesh your question out with more detail and make sure it's focused on a specific question? As it stands it's rather ambiguous. Firstly, by "efficient" I think you mean "effective" (i.e. does it work?). Secondly, what do you mean by "How many watermarks"? What usage do you have in mind? What are you trying to achieve by using watermarks? I think without being a bit more specific you're likely to get a lot of varied answers that may not be helpful to you or to other readers.
Comment: Particularly, do you mean a _hidden_ watermark, or a visible one?
Comment: Visible Watermarks
Comment: Hello. If you think you have received an answer, you should probably mark an answer.
Answer: A single watermark is most common, and mainly serves as a notice that the image is copyrighted.  A single watermark is often easily removed with editing, like photoshop's content-aware fill.  They tend to be a semi-opaque grey in order to not ruin the picture entirely, while being visible enough to serve their purpose.
An important point is that an image is copyrighted at the moment it is taken, and this is unaffected by the presence or absence of a watermark.  So adding a watermark does not increase your legal protection.
They can also be used as a branding tool to advertise a photography business, as opposed to trying to discourage misuse of the image.  A name and website so anyone who likes an image they see online can search and find the photographer.
Some agencies, like this one for example, cover their images with their watermark making it very difficult to remove.
Apart from visual watermarks, there is also digital watermarking, which is quite a different thing.  This is not visible to the eye, but is embedded in the image (the best analogy I know if is to compare it to digital noise in an image).  A lot of information can be encoded into the digital watermark.  For example, if you licensed an image to several clients, you could embed unique IDs in each copy so that if they were used elsewhere, you would know which of the images it was.
Answer: Watermarking is usually used as one per image in my opinion. Watermark usage can vary in terms of the fact that some people wish to create their own design of watermark, some prefer to keep initials, some try to outline the company/ organisation they are working for by putting their logo as a watermark etc.
Personally I think watermarking is usually used by people in order to avoid their good pictures getting stolen specially if they are uploading it on the internet websites like flickr or facebook.


Are termination resistors needed for UART, I2C and SPI?

Question: I see that termination resistors might be needed for some communication lines. What about UART, I2C and SPI, are they needed ? If yes, how do we choose their values?
Comment: What did you find so far about the topic?
Comment: It is dependent on the freqency. Usually something to match the transmission line impedance better... Typically 22 or 47 ohm resistors are used. If your signal is below 1 MHz, don't worry about them.
Answer: Take 50 MHz clock SPI.
50 MHz has a fundamental wavelength of 6 metres but you could argue that due to the fast rising edges everything up to the 5 th harmonic is potentially capable of disrupting the shape too much if terminations are not applied. So that's a wavelength of 1.2 metres.
On the other hand, on PCBs, the speed of signals is about 60% the speed of light so that fifth harmonic has a wavelength of 0.7 metres.
A sensible rule of thumb suggests reasonably that you need to consider adding a termination if the transmission line is longer that about one-tenth of a wavelength - so if your PCB tracks are more than 7 cm long then you should consider a termination but, you'll probably get away without one for a few more centimetres and, if the edges your chip generates are not that fast maybe you can consider the 3rd harmonic as the benchmark rather than the fifth harmonic.
The same argument applies for UART transmission but it's a little different with I2C because of the pull-up resistors and the inability to drive very fast edges due to the output device being active only in the low state.
Answer: UART signals transmitted with RS232 levels are done without termination resistors due to the slow rising and falling edges. But when RS485 is used for UART signals, termination ressistors are used frequently.


convert lognormal Cumulative Density Function P90 and P10 values to mean and sigma

Question: Practioners are used to defining lognormal distributions in terms of P90 and P10 cumulative density function values.  To utilize these esperts' input I need to be able to convert these P90/P10 values into parameters used in software which are mean and sigma.  How do I convert P90 and P10 lognormal CDF values into the distribution's mean and sigma values
Answer: It rather depends on whether "mean and sigma" are parameters of the log-normal distribution or the underlying normal distribution.  Let's assume the latter.
You take the natural logarithms of the P90 and P10 values.  Their midpoint should be the mean of the underlying normal distribution, and the distance between them should be about $ 2.563$ times the standard deviation of the underlying normal distribution: i.e. $\Phi^{-1}(0.9)-\Phi^{-1}(0.1)$ based on the cumulative distribution of a standard Gaussian distribution.


For multi-class classification in SGDClassifier how do I tell if it is using one-vs-rest or one-vs-one by default?

Question: According to the Geron book, for multi-class classification, SGDClassifier in scikit-learn uses one-vs-rest. But how can I tell which one is used as it doesn't appear to give this information in the help file.
Answer: It's there in the User guide [Link]

"....SGDClassifier supports multi-class classification by combining multiple binary classifiers in a "one versus all" (OVA) scheme. For each of the  classes, a binary classifier is learned that discriminates between that and all other  classes. At testing time, we compute the confidence score (i.e. the signed distances to the hyperplane) for each classifier and choose the class with the highest confidence...."


SWF never finishes loading over SSL in IE

Question: I have a flex application which was originally deployed on Tomcat running on windows.  It worked fine over both http and https in all browsers.
Recently, I switched over to websphere community edition on linux, and the application works fine, except in IE over https.  When access the application, the swf never finishes loading.  I just see the progress bar, stuck at 1/4 completion, and a white background.
I have researched similar issues on stackoverflow, and tried all suggestions but still it does not work:
I tried turning off caching at the top of my jsp where I embed the SWF:
<code><meta http-equiv="Cache-Control" content="no-store,max-age=0,must-revalidate">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</code>
I am wondering if websphere ce is putting something in the response header which is preventing my swf from loading over https, as it worked fine in standalone tomcat over https.
I do not see anything suspicious in logs, however, using Fiddler, I noticed the last thing it is doing is trying to download two cross domain files over http from fpdownload.adobe.com:
/pub/swz/crossdomain.xml
and
/crossdomain.xml
Then normally several BlazeDS calls are made.  This never happens.
Comment: Anything in the log files? I mean SystemOut.log, SystemErr.log, http_access.log, http_error.log
Answer: You need to remove all cache-control headers.
Check http://support.microsoft.com/kb/234067 for more information in this regard.


How can I call aspx content page methods from usercontrol? ASP.NET, C#

Question: How can I call aspx content page methods from usercontrol?
Answer: Probably the cleanest solution is to extract an interface containing the methods that must be called from the UserControl, and then pass the interface from the page to the control, e.g:
public interface ISomeService
{
  void Method1();
  bool Method2();
}

public class MyContentPage : Page, ISomeService
{
  void Method1() { ... }
  bool Method2() { ... }

  override OnLoad(...)
  {
    TheUserControl.SetService(this as ISomeService);
  }
}

public class MyUserControl : UserControl
{
  public void SetService(ISomeService service)
  {
    _service = service;
  }

  private void SomeOtherMethod()
  {
    _service.Method1();
  }
}

Another variation would be to simply require the page containing the user control to implement the required interface. This makes the SetService() method unneeded:
public class MyUserControl : UserControl
{
  private void SomeOtherMethod()
  {
    // page must implement ISomeService, throws an exception otherwise
    (Page as ISomeService).Method1();
  }
}

Answer: You are most likely creating a very bad design at this point. If it needs to have access to its parent, it probably shouldn't be a UserControl.  Are you sure you can't just add an event handler to your usercontrol that the parent page calls on certain events?
That said, your UserControl will have the .Page property you can cast to get your parent page.  Again, it's probably a very bad idea and you should revisit your design.