"I realized I had forgotten something" vs "I realized having forgotten something"

Question: Are the following expressions both correct?

I realized I had forgotten something.
I realized having forgotten something.

What is the difference in the meaning (if any)?
Comment: The second expression doesn't seem grammatically correct.
Answer:

I realized [that] I had forgotten something.

This is grammatically correct, and probably what you wanted to say. realized is in simple past, so you are talking about something that happened in the past. had forgotten is past perfect, which places it before the realizing.
Note that realize is usually followed by a that-clause, although the that is often omitted.

I realized having forgotten something.

On its own, this sentence is incomplete. having is a participle, and Having forgotten something is a participial phrase. Remember that realize requires a that-clause, and a phrase won't do. (A clause contains a verb, a phrase does not).
You might use it in a sentence like this, where there is an additional that-clause:

Having forgotten something, I realized that I would have to go back and get it.
Comment: The point, @Taiki is that your second sentence is ungrammatical.
Comment: The verb Realize is usually followed by a that-clause, that is the point. Thx :)
Answer: To realize is a reporting verb that can be followed either by "that- clause" or a clause starting with a question word (what, how, etc.). In "that-clause", that is often omitted, like it was in your first sentence.
Examples:

Only then did I realize that he was telling the truth.
Looking in his eyes, I realized how serious he was.
Having read the letter, I realized what she really meant by saying that.

As for your second sentence, I can't but absolutely agree with JavaLatte.
P.S. The provided links will lead you to the lists of numerous reporting verbs  and their usage to help you further your English.
Answer: In the first sentence at the moment you realized what you forgot, it was too late.

the door was already slammed when I realized I had forgotten my keys.

In the second one, having is the progressive form: at the moment you realized it, you could still correct the problem:

before I slammed the door I realized having forgotten my keys.


Excel Interop: Quitting the Excel application instance makes my tests fail?

Question: I want to encapsulate the use of Excel Interop to make it easier to use somehow in a reuseable library.
So far, I have written some tests that work good altogether, except that between each test, I force Excel to quite so that it does have handle on the test file no more in order to be able to delete.
Once I quit the application instance between after each of my tests, Excel seems to be no longer responding, causing Windows to display

"Excel has stopped working and is looking for a solution"

message. This message lasts a few seconds, meanwhile Excel is closing, causing the hang on the file to occur and my tests to throw an exception like

"Cannot access file because it is being used by another process..."

message. Otherwise, each of my tests run individually just fine!
Any clue on how to solve this issue?
Do I overuse the ApplicationClass.Quit() method?
Quitting Excel only once the testing is through with my tests causes the files created for the tests purpose not to be deleteable.
Thanks! =)
Answer: If you've made changes to the Workbook then could it be the "Do you wish to save changes?" dialog which is holding things up. You could try setting the _Workbook.Saved property to True prior to quitting the application. See here for details
Comment: +1 How couldn't I have thought about it before! Thanks a lot barrowc! =)
Answer: I was having the same "Cannot access file because it is being used by another process..." issue.
I was saving the worksheet, what you need to do is save the work book. Here's a full example.
private void TestCreateExcel(IEnumerable<Sales1> data)
    {
        var excelApp = new Excel.Application();
        var workBook = excelApp.Workbooks.Add();
        Excel._Worksheet workSheet = excelApp.ActiveSheet;

        workSheet.Cells[1, "A"] = "Title";
        workSheet.Cells[1, "B"] = "Author(s)";
        workSheet.Cells[1, "C"] = "Release Date";
        workSheet.Cells[1, "D"] = "Total Books Sold";
        workSheet.Cells[1, "E"] = "Last 30 Days Sales";
        workSheet.Cells[1, "F"] = "Average Sales Per Month";
        workSheet.Cells[1, "G"] = "Starting Advance";
        workSheet.Cells[1, "H"] = "Current Advance";

        int index = 1; //Keep track of the which row we're writing to.
        foreach (var n in data)
        {
            index++;
            workSheet.Cells[index, "A"] = n.Title;
            workSheet.Cells[index, "B"] = n.Author;
            workSheet.Cells[index, "C"] = n.ReleaseDate.ToShortDateString();
            workSheet.Cells[index, "D"] = n.TotalBooksSold;
            workSheet.Cells[index, "E"] = n.Last30DaysSales;
            workSheet.Cells[index, "F"] = n.AverageSalesPerMonth;
            workSheet.Cells[index, "G"] = n.StartingAdvance;
            workSheet.Cells[index, "H"] = n.CurrentAdvance;
        }

        workBook.SaveAs(Server.MapPath(filePath + fileName));
        excelApp.Quit();
    }


Add custom fields to Shipping Cart Price Rule and Catalog Price Rule

Question: I want to add one boolean field in each of Promotion Rule. Please can anyone suggest me how to proceed and which Model/Block need to be overridden.
Answer: Copy Main.php from
/app/code/core/Mage/Adminhtml/Block/Promo/Catalog/Edit/Tab/Main.php
To
/app/code/local/Mage/Adminhtml/Block/Promo/Catalog/Edit/Tab/Main.php
In function _prepareForm you can add your custom field:
<code>$fieldset->addField('custom_boolean_field', 'select', array(
            'label'     => Mage::helper('catalogrule')->__('Custom Field'),
            'title'     => Mage::helper('catalogrule')->__('Custom Field'),
            'name'      => 'custom_boolean_field',
            'required' => true,
            'options'    => array(
                '1' => Mage::helper('catalogrule')->__('Yes'),
                '0' => Mage::helper('catalogrule')->__('No'),
            ),
        ));
</code>
Comment: Only this much?
Comment: Yes, Field will reflect in catalog promotion form, Also save.
Comment: Is that works ?


Are There Link Layer Switches in the Network Core?

Question: Do we use link layer switches only in LANs, or are they deployed in the network core as well? I cannot picture the network core in my mind, is it just all routers starting from the edge router?
Comment: Are you referring to the LAN core or the WAN / Internet core ?
Answer: Your question is really too broad, and may need to be closed because it may start generating primarily opinion-based answers. There are also newer switches and topologies for data centers that do things much differently.
Cisco has (had?) a three-tier model model where the layer-2 access switches connected to the layer-3 distribution. The layer-3 distribution would then connect via a layer-2 core. The idea is that the core tier simply switches as fast as possible, rather than spend time routing, which is what is supposed to happen in the distribution tier.
That can be applied differently, depending on the size and needs of a site. For example, a medium-sized site could collapse the core and distribution into some chassis switches, while a small-sized site could have all three in a single device that combines a router with a switch module.
Another change is that the current best practice is to run routing on the access switches. They would connect via layer-3 to the distribution, rather than the traditional layer-2 connection to the distribution. They would still have layer-2 connections for the access interfaces. This practice eliminates many layer-2 problems that could spread (STP problems and broadcast storms), isolating any layer-2 problem to the single access switch.


When does the Stack Overflow week start?

Question: I assume it's either Sunday at 0 GMT or Monday at 0 GMT but I've tried checking a few things and searching and can't find when it is.  This is in regards to the weekly reputation leagues and "this week" and "last week" tabs of the recent activity page.
Answer: When you hover your mouse over the week, month, quarter and year buttons on the users page, there is a date range for each.
Comment: @Pollyanna: for me, 400 rep is a good day but not exceptional. 500 is pretty rare. 300 would be disappointing (on a week day, assuming I'm not on holiday). Anything less than 300 would be slightly embarrassing. On the weekend, 300 is reasonably gratifying.
Comment: Awesome, thanks!  Is it just me, or is it absolutely crazy that the top users are getting 400 rep per day, without bounties?  This means that in addition to getting 20 upvotes per day (which is nothing at their level), they are getting at least 14 accepted answers per day, every day.
Comment: Maybe I'm blind, but I can't find these.  Anymore.  The "recent activity" link in the OQ is dead, by the way, so it looks like some redesign did away with it. :-(  Which leaves this question open (again).


Does a dog know that it's a dog?

Question: According to Jewish thought, do animals have the self-awareness to know that they exist?  Do they know that they are animals?  Does an animal differentiate itself from other animals?
Comment: Animals act differently towards their own than to others, so they do differentiate. A lion won't eat a lion, but it'll eat other animals.
Comment: Related: in chassidus, an animal only cares about itself, only does what it wants. The head is physically equal with the whole body, not higher like people, because it's it's sechel, it's brain isn't above, doesn't control, the midos in the heart
Comment: I've moved a good number of comments here to [chat](http://chat.stackexchange.com/rooms/info/16937) instead, where you can continue the discussion, and deleted such comments as don't attempt to improve or clarify the question, including such as discuss the on-topic-ness of this question (which latter is being [discussed on Meta](http://meta.judaism.stackexchange.com/q/2160)).
Comment: User, generally speaking animals don't eat their own kind, but look at the black widow, it eats it's own husband to supply food for it's baby's! That's why it's called a black widow because after mates it turns on him. And snakes eat other snakes.
Comment: @user613 "A lion won't eat a lion, but it'll eat other animals." Some animals eat their own young. So you may be incorrect.
Answer: "There was a calf which was about to be taken for slaughtering, and it ran away, and put its head under the garment of Rabbi (Yehuda HaNassi), and cried. And Rabbi answered: 'Go; you are created for this purpose'. Then it was said by Heaven that, as he has no mercy with creatures, he shall be afflicted with chastisements." (Babylonian Talmud - Bava Metzia 85a)
This medrash, if taken literally, suggests some level of awareness on the part of the calf, perhaps related to your question.
Also (perhaps less relevant): "They further questioned: Why does the dog know his master, and the cat does not? and his answer was: It is certain that he who eats from what is left by a mouse is apt to have a poor memory, so much the more so the cat that himself consumes the mouse." (Babylonian Talmud - Horayot ch. III)
Comment: +1, I think these are good starting points.  But is it clear that the lack of mercy is because of the experience of the animal or perhaps because of his own lack of sensitivity, regardless of the animal's feelings?
Comment: How about Isaiah 1:3: "The ox knoweth his owner, and the ass his master's crib"?
Answer: Animals seem to know things outside themselves Yeshaya 1(3)

An ox knows his owner and a donkey his master's crib;

On which Rashi comments:

Heb. קֹנֵהוּ [is] like מְתַקְּנוֹ, the one who affixes him to the
  plowshare for plowing by day, and since he has accustomed him to this,
  he knows him. The dull donkey, however, does not recognize his master
  until he feeds him.

Rashi's comment might suggest that self-knowledge is unlikely in animals.
Comment: Does this mean that they don't have self knowledge, or (like I think it is) just a statement about classical conditioning in animals? http://en.wikipedia.org/wiki/Classical_conditioning
Comment: @Shokhet I see your point. I wanted to suggest that Rashi regards the donkey as less aware since he only recognises his master when he is fed (rather than when he is prepared for work). I see in this a very low level of awareness and infer (possibly) that self awareness is most unilkely.
Comment: Fair enough. [15 char]

Does a dog know that it's a dog?


I do have a lot of ice and snow on the roof should I install an ice melting cables

Question: I don't have ice damming but do have a lot of ice and snow on the roof should I install a ice melting cables?
Answer: No. Best case scenario you just waste the money that it would take to install them, worst case scenario you create a problem that didn't exist before.
Ice dams are typically created by sharp surface temperature gradients on roofs, usually caused by inadequate insulation in the attic.  Heated air escapes through the attic and warms the roof deck, melting the bottom of the snow accumulated there.  The water runs down the surface of the roof until it gets to an area that isn't being heated from below (typically the eaves), where it freezes again and creates a dam.
If you don't have an ice damming issue and start melting snow off of the eaves, the surface temperature gradient will be at the top of the ice melting cable.  Gravity will be on your side in this case, but there is still a risk that you'll get ice forming above the ice melting cable.
Finally, having snow accumulate on the roof is only a problem if there is too much weight. Outside of that, you want to have snow on your roof because it provides some additional insulating value and an excellent wind barrier. As an interesting side note, you can see this incorporated into traditional building designs in different parts of the world.  Areas with heavy snow falls tended to have steeper roofs, but they get less steep as the snow fall drops off largely in order to balance the amount of snow that stays on the roof.
Comment: Many thanks to you and @henryjackson, for all of the good data :)
Answer: If you are worried about ice dams forming, one very effective (and cheap) thing you can do is use a snow roof rake to remove snow from the bottom ~3 feet of the roof. That is where melted snow is likely to build up and refreeze into a dam, so by keeping that area clear you greatly reduce the chances of an ice dam forming.
(If the rake handle is long enough you may be able to remove the snow from most of the roof, but that's probably not necessary unless you have a history of water leaking or you are concerned about the structural integrity of the roof.)
Answer: I second the opinion on using a snow roof rake. As long as it reaches the area above the gutters. You want to leave some snow on, but you don't want icicles to form. I have the cables (from a previous owner of my house who left them) and after observing the roof through my first winter in the house, I concluded that they provide no significant benefit that you can't implement just by raking off the snow from the roof after the weather system is finished. To confirm my opinion, I drove around the neighborhood and observed others doing the same thing.
The cables are really just a lazy option.


Difference between CAPTCHA and reCAPTCHA

Question: What are the differences between CAPTCHA and reCAPTCHA?
What is the best situation to opt for reCAPTCHA?
Comment: Recaptcha is captcha. Captcha is not recaptcha.
Comment: we also got hCAPTCHA now..mostly used by cloudflare.
Answer: CAPTCHA is the human validation test (usually the blurry squiglly letters that need to be deciphered) used by many sites to prevent spam.
reCAPTCHA is a reversed CAPTCHA - the same test, used not only to prevent spam but to help in the book digitazion project. In other words, the reCAPTCHA tests are not meaningless combination of words, but excerpts from books that undergo digitation, while CAPTCHA uses several human validation methods including math or general knowledge questions, visual puzzles and even chess puzzles.
Google purchased reCAPTCHA several years ago, and now it is also used to collect street view data
Answer: A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a program that can tell whether its user is a human or a computer.
The process involves a computer asking a user to complete a simple test which generated by computer. Because other computers are unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human. Sometimes it is described as a reverse Turing test, because it is done by a machine and targeted to a human. reCAPTCHA does exactly that by channeling the effort spent solving CAPTCHAs online into "reading" books.
reCaptcha is hosted by Google, and one of the more interesting things about it is that it is used to digitize text of old newspapers and books. That's why there are two "sections" of a reCaptcha instead of the single series of characters for CAPTCHA - one is known text, the other is not. If you get the known one correct, it assumes you got the second one. Then the next time it offers up that same "unknown" text, it is considered possibly known.
A few more times with the same result for the "unknown" text, and it becomes "known" and the text it originated from can be correctly digitized. Clever, eh?
Also, because of frequent updates, I would expect reCAPTCHA to be slightly better at preventing bots from solving them.
Reference: https://anydifferencebetween.com/difference-between-captcha-and-recaptcha/
Comment: @KalyanRaghu I hope now it is... :)
Answer: reCAPTCHA is a type of CAPTCHA. It is easier for humans and relatively difficult for bots to crack, which is the sole purpose of having a CAPTCHA in forms. If you need a CAPTCHA, go for reCAPTCHA.
Answer: I think I remember CAPTCHA from a few years ago for Gmail.
reCAPTCHA is easier for people. I usually had some difficulty getting past the old CAPTCHA, because I couldn't quite read the letters and had a hard time seeing the difference between "O" and "Q" or other similar looking letters like "mn" or "nm".
I recommend reCAPTCHA over CAPTCHA since it's easier for actual users, and you can always add a firewall to help block bots.


fonts supported by android devices

Question: I am developing an android application using corona sdk,but i am not able to support all the custom fonts in my application.Many of the fonts which are supported in simulator are also not getting supported in the device.Very few fonts are getting supported in the device like ayuthaya.What is the reason for this? Can anybody give me any solution regarding this and also the list of fonts which is supported in the device.
Answer: You may have to download the fonts from the internet if you don't have them on your computer.
Answer: Download the font file (ttf or otf format) from the internet and include it on your project when building for Android. The device should be able to recognize it.
Answer: If you are on Windows, you should install the font on your computer. You can do that by right clicking your font and open with Windows Font Viewer. Then install the font and keep in mind the font name displayed in Windows Font Viewer because you are going to use that name as parameter(not filename of the font) in the code. And finally drag the font file into your project folder where your main source file is and also into project in IDE. After that, you should be able to view the font.
Answer: Be aware of the file name, it should be the same as you call it in your project.
Sometimes you would have to rename .ttf file.
To make it visible in simulator copy downloaded font file to windows/fonts folder.

fonts supported by android devices


What improvements exist between 32-bit and 64-bit Skyrim?

Question: Regarding the new Skyrim Special Edition, I heard it will be a 64-bit version. How/what does this improve?
Comment: I honestly do not think that this is a duplicate of the alleged question as answers to that question are completely unrelated to this one and answers to this one are completely unrelated to that one. This is asking about what a specific difference means for the game itself and the other is simply asking what differences are there.
Comment: It seems like a general "Are there any differences between a 32-bit and a 64-bit version of a game?" might be helpful.
Comment: @MageXy, I don't think that this is a duplicate of that question, as this asks specifically what the 32 to 64 bit conversion means for the game. That just says that there is a conversion.
Comment: @Vemenous Perhaps a change to the title would alleviate some of the confusion between the two questions?
Comment: @Kaizerwolf, yes, the title change helps, but I'm still unsure whether this can be called a dupe of the question *I* linked, even though they ask the same question.
Answer: One of the prime advantages of a 64-bit executable over a 32-bit one is the fact that the 64-bit one can address a significantly larger address space (that is, it can use more RAM).
A 32-bit executable can address 4GB of RAM, in theory. On Windows, in practice, that's limited to 3GB if the executable as the "large address aware" switch on, and only 2GB if it doesn't (because of what Windows reserves for itself).
A 64-bit executable, on the other hand, can address significantly more; the upper theoretical limit is measured in exabytes. In practice some architectures will only support 48 addressing pins, but even with 48 bits of physical address space, you're looking at a RAM ceiling that's much higher than what you can realistically put in a consumer desktop anyhow, and you're not confined to the arbitrary 2-or-3 GB limitations Windows enforces on 32-bit applications.
The 64-bit instruction set also affords some performance-improving options to the compiler that builds the executable. It's likely that Skyrim benefits somewhat from these. But I would expect that it's the ability to use more of your RAM, and thus fit more and bigger things into that RAM, that is going to be the biggest improvement afforded to the game by having a 64-bit executable.


Performance of different CG/GLSL/HLSL functions

Question: There are standard libraries of shader functions, such as for Cg. But are there resources which tell you how long each takes... I'm thinking similar to how you used to be able to look up how many cycles each ASM op would take.
Comment: It varies from device to device
Comment: I guess, nowadays more important is how many processors can you load up. If you set a heavy shader with dependent texture reads, you'll get stalls and waits and other unpleasant stuff. Pure "cycle count" won't help in this case.
Comment: Both true - but some idea would still be useful as a starting point. For instance the mathematical/geometrical functions... how does division compare against cos, or cos against acos, or sqrt against tan...
Comment: @John I guess they are generally more or less the same cycles, but I cannot say how they perform in comparison to simple MULs and ADDs. But what I know is that at least in NVDIA's architectures the multiprocessors have fewer ALUs for transcendental functions (like sin, sqrt, ...) than simple MUL/ADD-ALUs (maybe 8:1 or 4:1), So they can perform more MULs/ADDs in parallel than SINs/SQRTs. Other than that you might have to ask the the individual GPU developers.
Answer: There are no reliable resources that will tell you how long various standard shader functions take. Not even for a particular piece of hardware.
The reason for this has to do with instruction scheduling and the way modern shader architectures work. Take a simple sin function. Let's say that the hardware has a special hardware to compute the sine of a value, so it's not manually using a Tailor series or something. However, let's also say that it takes a sequence of 4 opcodes to actually compute it. Therefore, sin would take "4 cycles".
However, all of those opcodes are scalar operations. Therefore, while they're going on, you could in fact have some 3-vector dot-products, or in the case of some hardware, 4-vector dot-products going on at the same time, on the same processor. Therefore, if the hardware has 4-vector dot-products with scalar operations, the number of cycles it takes to execute a sin and a matrix-vector multiply is... still 4.
So how much did the sin operation cost? If you take out the matrix multiply, nothing gets faster. If you take out the sin, nothing still gets faster. How much does it cost? You can't say, because the cost of a single operation is irrelevant; the only measurable quantity is the cost of the shader itself.
Ultimately, all you can do is try to build your shader reasonably and see what the performance is. Unless you have low-level debugging tools to deprocess the underlying shader assembly (and no, DX assembly isn't good enough), that's really the best you can do.


What is a good book to read about 3D printers?

Question: I've been interested in 3D printing for the past month however, I have noticed that it's sort of a "reserved" topic. Meaning that everyone who talks about it, has already some basic knowledge about the topic. What are some good resources for someone who wants to start learning from zero? My main goal is to acquire enough knowledge in order to build my own 3D printer.
Comment: I don't understand the want to close everything that doesn't say what specific printer they are using and what the alloy is of the bolt that is driving the filament.  Answers to this question would not only be beneficial to the original poster but many other new people that find the site as well.  The question is easy enough to answer and I'm sure all of us have a few websites that we check daily for information.
Comment: As it stands, I think this question is too broad for the requirements of this site. I understand the state of not knowing what questions to ask, but this site is designed for more specific questions. Perhaps try rewording your question to outline what resources haven't worked for you and what type of information (specifically) can help you start your adventures in 3D printing. Best regards and welcome!
Comment: @Trish This question was asked when the site was only 4 months old and struggling to get started.  The site needed questions then and still needs questions today. What do we gain by closing a 2.5 year old question with 5 answers?
Comment: @tjb1 this is a *shopping* question as there are as many good answers as there are books about the topic.
Answer: You can learn a lot just by reading the forums.  I'll just list a few that are quite popular...
Reprap Forums - Has a ton of information on DIY printers including build logs and posts dealing with many issues.
Soliforum - Large user base with lots of information. Not sure what it's standing is now that Solidoodle is gone but I'm sure the forum will stick around.
SeeMeCNC - Support forum for SeeMeCNC, has a lot of information for Delta printers and also other printers.
There aren't many books that I know of...Make magazine has done a few issues on 3D printing that you could try to obtain.  I'm not sure what your idea of building a printer is, do you want to design your own or follow someone's instructions and put one together?  Designing one would require some basic hardware and engineering knowledge.
All that said, the best learning experience would be buying a kit and learning as you go.  You'll never read in a book what you will learn from having your own printer.
Answer: The resources you have at your fingertips are going to be more up-to-date than anything you'll find in a paper/published book. Use this amazing thing called the internet and read everything you can find. Use Google or your favorite search engine using appropriate terms. I'd suggest, based on your overly broad question, that you use "build your own 3d printer" as a starting point.
You'll find that Instructables is one useful resource as well as MakerShed for additional material. You will find a very large source of helpful information at 3dprintboard.com simply by reading others' posts there and at other forums as well.
There is quite a bit to absorb and understand but with the internet at your fingertips, you won't be lacking for information.
Answer: I would recommend Design for 3D Printing: Scanning, Creating, Editing, Remixing, and Making in Three Dimensions by Samuel N. Bernier, Bertier Luyt and Tatiana Reinhard

It has a lot of tips, tricks and examples.
Good for beginners and experienced users.
Answer: ADDITIVE MANUFACTURING TECHNOLOGIES
3D Printing, Rapid Prototyping, and
Direct Digital Manufacturing
Springer
I think its a perfect book. A lot of details to all technologies.
*Beware there is math and physics involved.
Answer: If you really want to learn about three dimensional printing then "Mastering 3D Printing" by Joan Horvath, published by Apress, would be a good place to start.
It does not provide you the in depth knowledge about all the types of printers or materials but it is good enough to get a newbie like me or you get of the ground.


Is there a master list of journals?

Question: I'm looking for a repository of journal data.
More specifically, a listing of every known journal name and various attributes such as ISSN, rankings, peer review, etc. I know Cabell's offers this information, but expressly forbids mass-downloading.
Is there a better source for Journal data?
Answer: The short answer is no. There is no comprehensive list of academic journals, and I doubt there ever will be. The major reason for it is there is no real need as publishing culture varies a lot by field and geography. Plus, in the recent explosion of scholarly publishing, there is probably a new journal every week or so.
However there are curated databases of journals. For example, Thomson Reuters has a service called Web of Science that provides libraries with a large list of journals (about 12'000 according to Wikipedia) and publication metrics, such as citation count, rank by discipline and impact factor. I used this service a few times to check the ranking of journals before submitting papers.
Libraries often let affiliates download the full report as a spreadsheet that you can manipulate the way you want. Contact your local library, most institutions subscribe to this database.
Also, this list might be useful to you.
Answer: At the university where I did my PhD, we used the Norwegian Scientific Index to establish what journals were considered "valid" for an internal system of redistributing money based on scientific output.  From Wikipedia:

The index divides journals and publishers into "level 1" and "level 2", where "level 2" is reserved for the internationally[1] most prestigious journals and publishers within the discipline

(...)

Currently, 2,144 academic journals and series are designated as Level 2, i.e. journals and series considered to be the most highly regarded

This is not a complete list, but a list that aims to contain the "good" journals within each discipline.
I don't know about mass downloading — perhaps the folks at the Open Data Stack Exchange have a better take on that.
Comment: There are many such national lists for funding and evaluation purposes. They tend to be heavily controversial.
Answer: There is also the Journal Citation Reports list provided by Thompson Reuters. To access it you will need to ask your library.
Answer: If you only want a list of "good" journals, DOAJ (Directory of Open Access Journals) is probably what you need. It contains about 12 thousand journals passing certain checks, of which over 1000 with further quality controls (DOAJ seal).
Wikidata is open data and run by a non-profit, as well. It's participatory and general purpose and it has a lot of data on journals, partly thanks to a specific initiative called WikiCite.
You can rather easily query and download a list of all academic journals (and subclasses thereof). As of now I see about 50 thousands results, nearly all of them having ISSN and many also license and publisher information. See the SPARQL query service documentation on how to tweak the query.
Answer: The closest that comes to a master list of journals is the following:
This CSV-file on GitHub containing ca. 25.000 journals belonging to 137 major* publishers. You can also browse through the same list on this website.
The catalogue stems from a project that scraped data based on (1) DOAJ, (2) Publons, (3) Scopus and (4) Sherpa Romeo.
For details, see the pre-print here.

* I.e., publishers that supposedly had at least 30 journals in their portfolio based on the journal counts in one of the four data samples (DOAJ, Publons, Scopus or Sherpa Romeo).
Answer: You might find the Australian ERA list useful. It has been used by the Australian government to evaluate university research performance.
I'm not sure what is the most stable link. But this search seems to get a few copies of it.
It appears to have around 22 thousand journals. It contains ISSN and discipline category information.
See the list here:
http://www.arc.gov.au/era-2015-submitted-journal-list
Comment: This is no longer used.
Answer: A place to start: the ISSN Portal
This will include not only journals, but magazines, newspapers, periodicals, and other continuing resources.

Is there a master list of journals?


Is it "species of plural" or "species of singular"?

Question: Is it correct to say "a species of moth" or "a species of moths", or are they both correct? Is it the same if I use "family" or "genus" instead of "species"? Does it matter if I continue with another taxon, such as "This is a species of moths in the geometrid family."
Comment: Singular is more idiomatic.
Comment: That's true for some things, but not all. "A species of louse" sounds funny compared to "a species of lice."
Answer: As mentioned in Jesse Ivy's answer, "species" is of course a plural form as well as a singular form. In expressions like "many species of moths", "several species of moths", "various species of moths", the plural ("moths") seems at least strongly preferred.
When "species" is used as a singular noun ("a species"), it seems to be preferred to use a singular noun after it. The Google Ngram Viewer indicates that "a species of moth" is more common than "a species of moths":

In fact, according to the Google Ngram Viewer, "a species of mouse" and "a species of louse" also seem to be more common than "a species of mice" and  "a species of lice". So irregular plural forms, in and of themselves, don't seem to have that strong an effect on the acceptability of the plural in this context.
However, the word algae is not only an irregular plural, but is often treated as a mass noun, and "a species of algae" does seem to be somewhat more common in the present day than "a species of alga":

Similarly, the mass noun "grain" does not typically seem to be pluralized after "species of", even in contexts where "species" is plural like "five species of grain" or "several species of grain".
Another word with an irregular plural sometimes treated as a mass noun is bacteria, and "a species of bacteria" and "a species of bacterium" seem to be relatively close as well.
To me, "a genus of moth" or "a family of moth" sound completely unacceptable. For "family", I suppose part of it is probably that a "family" is typically used to describe a collection of individuals, in its other uses as well as in its biological use. I can't think of any particular explanation for why the singular sounds bad with "genus". Janus Bahs Jacquet has left a comment saying that the singular does not seem impossible for him after "a genus of".
Comment: The Ngram 'species of moth' vs 'species of moths' is about 50/50, I notice. https://books.google.com/ngrams/graph?content=species+of+moth%2C+species+of+moths&year_start=1800&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cspecies%20of%20moth%3B%2Cc0%3B.t1%3B%2Cspecies%20of%20moths%3B%2Cc0
Comment: "A family of moth" sounds quite unacceptable to me too, but "a genus of moth" doesn't. Less natural, but not impossible. Substituting plants for the moths, [the relevant Ngram](https://books.google.com/ngrams/graph?content=genus+of+plant%2Cgenus+of+plants&year_start=1960&year_end=2010&corpus=18&smoothing=3&share=&direct_url=t1%3B%2Cgenus%20of%20plant%3B%2Cc0%3B.t1%3B%2Cgenus%20of%20plants%3B%2Cc0) shows that the plural is more common, but the singular not unknown.
Comment: @JanusBahsJacquet: A certain proportion of that seems likely to be false hits like "genus of plant viruses", although there are some real singular examples on Google Books. The information that "a genus of moth" sounds not entirely unacceptable to you seems interesting; I may have to do some more research and edit the last paragraph
Comment: @NigelJ: Right, but that doesn't distinguish between singular uses ("a species of moth") vs. plural uses ("many species of moths")
Comment: Ah yes. I did it again with 'many species of moth/moths' and it proves your point. https://books.google.com/ngrams/graph?content=many+species+of+moth%2C+many+species+of+moths&year_start=1800&year_end=2008&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cmany%20species%20of%20moth%3B%2Cc0%3B.t1%3B%2Cmany%20species%20of%20moths%3B%2Cc0
Answer: Good question. The word species is both singular and plural. To complicate things, the singular refers to a group of creatures with similar characteristics. So they are all correct, but mean different things. I like your last example best which has the same meaning as the first, referring to one specific "species of moth". Singular.
In the second example you've given, you are referring to multiple "species of moths". Plural.
In conclusion, a "species of moth" is singular, while several "species of moths" is plural.
Of course the singular form refers to a group, whereas the plural form refers to a group of groups.
https://www.quora.com/Is-species-singular-or-plural-How-do-you-say-the-alternate-version-of-the-word
https://en.oxforddictionaries.com/definition/species
Bonus Update
For scientific citation use the binomial name, like you listed, only if a genus exist I think that's used in place of family, you've got it reversed in your example, and there is special formatting.

Binomial Name
The binomial name consists of a genus name and specific epithet.  The scientific names of species are italicized. The genus name is always capitalized and is written first; the species epithet follows the genus name and is not capitalized. There is no exception to this.

https://www.enago.com/academy/how-to-write-scientific-names-in-a-research-paper-animals-plants/
Also known as binomial nominclature.
http://www2.nau.edu/~bio372-c/class/evolution/binom.htm
i.e Attacus atlas moth
http://www.nhm.ac.uk/discover/spotlight-the-atlas-moth.html
Answer: Species is either singular or plural. The word that comes after "of" is just describing what kind of species it is. Therefore, the number is determined by the introductory word "this" or "these." The word after "of" should always be singular.


Access root filesystem from U-boot

Question: I'm trying to debug an embedded device, connection via serial port, connected with USB to UART cable. Embedded Linux v.18.104.22.168 How to access the root filesystem "/" and subdirectories under the root FS? The shell command is not available in U-boot mode. Is there a way to access shell CLI from U-boot?
The available U-boot commands and logs is here and here.
Answer: I guess you need to Follow the Third stage of U-boot.
The third stage is the loading of the Linux kernel. However, before the Linux kernel takes control, u-boot passes a command line to the kernel containing essential parameters. These parameters can be viewed after the operating system has booted by typing the following into a Terminal window:
$ cat /proc/cmdline
root=/dev/mmcblk0p2 rootwait rw console=ttyS0,115200n8 console=tty0 no_console_suspend vdaccfg=0xa000 logo=osd1,loaded,0x7900000,720p,full dmfc=3 cvbsmode=576cvbs hdmimode=1080p m_bpp=32 vout=hdmi disablehpd=true

The kernel initializes the hardware, mounts the root filesystem (according to the root=... kernel parameter) and passes the control flow to /sbin/init. if you need more details abt Uboot Follow this link
Comment: You mean I need wait until the Linux kernel fully loaded (stage 3 of U-boot), not interrupt the automatic boot process?
Comment: follow the link i gave below the stage 3 there is Disk layout and partitioning and u-boot environment setup . which ll help you setup ur / partition.
Answer: Depending on the filesystem and media you might be able to dump data in hexadecimal form directly under u-boot shell. If you are reverse engineering observe help output to understand what type of media storage device access and manipulation commands you have compiled in to U-boot and go on from there. After loading to memory or maybe even sometimes without it you can use 'md' to dump it. Use load addresses after the u-boot portion in memory or it will reboot. Keep in mind that most of the times the filesystems are compressed and can't be permanently modified (squashfs is common). Sometimes u-boot comes with a command that can load and read the uncompressed data. Peeking the filesystem from memory dump can be tedious so it's often best to log an entire partition dump locally, convert it to binary and deal with it locally.
You may succeed loading a shell by modifying the init= kernel argument to point to a shell program. Usually with embedded devices it's busybox so that would be /bin/ash.

Access root filesystem from U-boot


rke etcd snapshot have so many errors

Question: i have to backup my kubernetes cluster.
i choose Etcd backup with rancher rke but after restoring the backup i have too many differente errors on pods like Calico, Nginx-ingress-controller, kube-dns and ... .
is Etcd backup reliable?
what is the best backup tools for kubernetes?
i tried step by step restore from:
https://rancher.com/docs/rancher/v2.x/en/backups/restorations/ha-restoration/#4-restore-database
Comment: Please, upvote/accept the answer to let know community about usefulness, thanks!
Answer: One of the most popular is Valero, which gives you tools to back up and restore your Kubernetes cluster resources and persistent volumes. You can run Velero with a cloud provider or on-premises. It is well documented. You can check installation overview to see details.
You can also check tutorial how to srart with Valero. If you have more question feel free to ask.

rke etcd snapshot have so many errors


Workplace review and pay rise

Question: I'm working for a company in southern England having joined from university in the summer. I have worked above the level I was brought in at, developing projects, visiting clients, delivering solutions when I was brought in as support to then progress into this over a year. 6 months in I'm due my review. I was never expected to travel much for work but I do, and I work hard, I'm new I want to impress. Is it too early to ask for a pay increase? Considering the main thing here is, I'm doing a job above what I was brought in to do?
Comment: Most companies have a annual review process where salary increases are considered
Comment: Strictly, this is asking "Is it too early?", not "How do I ask?".
Answer: Six months is pretty early to ask for a raise. A year to 1.5 years feels more reasonable -- especially if you are young / just out of university. You haven't "paid your dues" yet.  Additionally, you may work hard and have a very bright future, but chances are you don't have a lot of polish (yet). Also, it is not unusual for there to be a moderate pay increase at the end of a 6 month probation anyway. Finally, they are paying you in experience that many don't get at your stage of career development. That will reap rewards later on.
However, if you feel strongly that you are grossly underpaid, or that your work is much more demanding than what your pay grade would suggest, and you must bring it up at 6 months, then I would take a middle-ground approach. I wouldn't demand a pay raise (yet), but I might bring up the topic.
At the end of the review I would say something like, "ok. Can I mention an important topic? I love my job and am happy here. However, since starting here I have taken on the additional roles of client support, traveling, project planning and development, etc. I'm interested to know if these additional responsibilities will be reflected in my compensation."
Then stop talking and let them reply. Personally, I don't think I would be any more aggressive than the above at 6 months. 18 months? Yes; you have a more proven track record. But 6 months? No.
Answer: If you're doing work that goes above and beyond the expectations for the position when you were hired, you certainly have the right to ask for a pay increase.  There may be better options, though, than focusing on asking for more money.
If you like the company and think you may have a future there, you could point out that you are doing work beyond your original expectations and ask that your review include a talk about your future career path, including aligning your title and responsibilities closer to the work that you're doing right now and adjusting salary accordingly.  This lets the company know that you're not just interested in a pay rise; you want to manage your career over the long term, which is actually more important for a recent graduate.
On the other hand, you think you will move on relatively quickly, it may be more beneficial to ask for an adjustment to your title than to angle for a pay rise.  Asking for a title change to better reflect your responsibilities will indicate your value to future employers and may increase your income over the long term more than a pay rise at your current title.
Bottom line - think about your long-term career path when review time comes around, rather than thinking only about short-term gain, and plan to focus the conversation accordingly.
Comment: This is a very good answer.
Comment: agreed, appreciate the alternatives and avenues I can look at.
Answer: This is a balance of your market worth, and your value to the company. Your level of effort and expectations are secondary.
If you are substantially under your market worth, and the company is happy with you--you may be able to lean it. You'll want to raise the issue gently so you can get a "no" and stay without tarnishing yourself. For instance, it's okay to ask out of curiosity if you'll still be in an annual review, or what the normal process is, if the annual review is used to give warnings, assign bonus/raises, etc. Ask without asking if you can.
If you are at your market value or your company is still unsure, asking is risky.  It sounds like you are at your market value, and being patient may help to get a bigger raise when the normal process comes around.
(For completeness, if you're over market value or your company isn't happy, don't push the issue--pushing a decision could cost you the job. This doesn't sound like your case.)
Doing a job above what you were brought in to do is fine. Many promotions happen because people start taking over tasks above their pay grade. Consider this: imagine I told you that you have two choices.  One--you can do the work above your pay grade for a year, and then there's a much better chance that you'll be promoted and recognized after that year with more money. Two--you can do the work at your level, and hope to be promoted and recognized next year based on the performance at the lower level.  If you'd choose One, then you're right where you would be.

Workplace review and pay rise


What to do about mini-answers that could as well be a comment to an existing answer?

Question: See e.g. here. The answer does not mention anything the other answers didn't mention 9 hours before, except for a (indeed useful) link. Shouldn't this rather be a comment on one of the answers?
Answer: If the answer adds new information - in this case a link - then there's nothing wrong with it. If the link is useful up-vote, if not down-vote (if you really feel strongly about it). A comment asking for the relevant information from the link to be quoted might be in order, but that depends on how much would have to be quoted.
If it's from a new user (one with less than 50 rep) then they can't comment, so in these cases I'd leave a comment but not do anything more. After all down-voting would just postpone the time at which they could use the site properly.
Comment: @Tobias - in that case add a comment to that effect.
Comment: In this case the user has rep to comment, and his answer consists of a link to a site which just states what another answer has already quoted from a manpage. I don't know if this additional link is useful, though it certainly isn't a reason for a downvote. The question is rather, should such answers be commented to encourage users putting minor additions as comments to existing answers or just leave it as is, which will probably not gain any upvotes anyway.
Answer: I've seen better examples for those oneliners. But if they`re bad enough, they get their downvotes or at least comments. The referenced example is instead fine to me. I'm not a unix crack and my first impression was, that this is somehow different answer to the question. And there's a link that might help the OP more than the other answers...
I've seen people leaving answers as comments but to my experience those are mainly members with high reputation who just don't want to get upvotes for simple google or tutorial links.


Differential Equations and Mortality Rate

Question: What if I try to model the mortality rate of a certain province and then to relate it to Differential Equations, the analysis on the rate of change will be expressed to a DE like the death is proportional to the population (just an example) as an end goal. Is this plausible or is there already a DE expressing the proportionality of death rate to something? My point is, out of the time-to-time analysis of death rate, I'd like to create a DE out of it and find the general formula that estimates future number of death in t time just like population growth rate. Is this possible? Or there are already given solutions/formulas to finding or estimating future death numbers? Thanks.
Answer: It's plausible and there's been a huge amount of work along these lines already. See for example Mathematical Models in Population Biology and Epidemiology by Brauer and Castillo-Chavez, an excellent book.


Difference in difference using spss

Question: I have 2 groups of patients (control and treated) and 1 variable measured at two time moments (before and after treatment).
Using paired T test I am able to determine the mean (with 95%CI) difference in each group (at baseline and after treatment). Using split-plot ANOVA I can say that the effect of the treatment is not different between the two groups (from the Test of Between Subjects Effects). But I am not able to determine the difference in difference (mean with 95%CI).
I forgot to say that I am using SPSS.
Thank you
Answer: For difference in differences you can compute the mean of the outcome $Y$ for each group $g =$ {$C$ control, $T$ treated} in each period $t =$ {1 pre-treatment, 2 post-treatment},
$$(E[Y_{igt}|g=T, t=2] - E[Y_{igt}|g=T, t=1]) - (E[Y_{igt}|g=C, t=2] - E[Y_{igt}|g=C, t=1])$$
which you can do by hand with the corresponding if-statements in SPSS. If you need confidence intervals, a convenient way to achieve the same calculation as above is to run the OLS regression
$$Y_{it} = \alpha + \beta_1 \; \text{Treat}_i + \beta_2 \; \text{Post}_t + \beta_3 \; (\text{Treat $\cdot$ Post})_{it} + \epsilon_{it}$$
where $\text{Treat}_i$ equals one for individuals in the treatment group and is zero otherwise, and $\text{Post}_t$ equals one for the post-treatment period and is zero otherwise.
The parameter $\beta_3$ then estimates the difference in differences and the regression will provide you with standard errors, p-values, confidence intervals etc. All you need to do in SPSS is to create the treatment dummy, the second period dummy and their interaction, and then run the described regression.
Comment: Thank you for your answer. I've followed your indications, but I want to know if I've done it correctly. First, since I had my variable of interest in two different columns, I restructured my dataset and also created my pre-post (Post t) dummy variable. Second, I created the interaction variable (between treatment group and pre-post variable). Third, I performed the linear regression with my variable of interest as the dependent variable and the other 3 as independent ones. My question is if the Unstandardized B Coefficient from the output is what I was searching for (the DID)? Thank you again
Comment: The regression coefficient $\beta_3$ will be exactly the difference in differences that you can calculate by hand from the group-time means. So take the mean of the outcome for the treatment group in both periods, take the difference. Then do the same for the control group, and then take the difference between those two differences. That's exactly what your regression coefficient $\beta_3$ will be, just that the regression gives you the confidence interval you wanted.
Comment: I've done it also by hand and yes (not surprisingly) you're right. The same result. Thank you very much.
Comment: Excellent :-) with the standard error/p-value/confidence interval you can now also say whether this difference in differences is statistically significant.

Difference in difference using spss


Why did the kingdoms of Scotland and England merge?

Question: I'm from the states, so I'm not so sharp on the history of various European monarchs. Having been told as a child that my ancestors emigrated from Scotland, I've always had an interest in the country. So to sum up, what led up to, and eventually caused the merger of the Kingdom of Scotland and the Kingdom of England?
Comment: Thanks for the question, but the answers are readily found in places such as http://en.wikipedia.org/wiki/Acts_of_Union_1707 . I encourage you to reformulate your question so that it is acceptable under the FAQ (i.e. not general reference).
Comment: Welcome to the site. An upvote to get started, per custom, and also because the question is interesting!
Comment: My mistake, was browsing the page of the union of crowns and it didn't really mention anything about the merger of nations, or how it came to be. Now I see that they are two different things.
Comment: I see under the FAQ, that this may be general reference, however; I feel it is complicated enough to warrant an explanation. Nearly everything on this site is answerable by a wikipedia page. History, after all, is recorded.
Answer: The first attempt at unification was sparked by succession disputes, after Margaret of Scotland died in 1290. This lead to a series of conflicts, spanning from 1296 to 1357, known today as the Wars of Scottish Independence. Scotland retained its status as an independent nation after the end of the wars.
The claim of Mary, Queen of Scots to the English throne ended up with her losing her head (literally), however when Elizabeth I of England died, Mary's son, James VI of Scotland was proclaimed King of England and Ireland (as James I), leading to the union of the crowns (1603). Scotland still remained a sovereign state, sharing a monarch with England.
The Glorious Revolution (1688) created fertile ground for union debates and unification eventually happened in 1707, with the Acts of Union. The years prior to the Acts of Union, Scotland had faced a famine, the "ill years", and was in a poor financial state after the failure of the Darien scheme, a series of expeditions to establish a colony on the Isthmus of Panama.
Further reading:

Acts of Union: The creation of the United Kingdom
Union with Scotland Act 1706
Act of Union 1707
Comment: @Kev Darien was privately funded but it's estimated to have consumed 25% of all Scottish capital at the time. Its abject failure was a massive blow to the Scottish economy.
Comment: It's latitude dependent: Either because Scotland was bust and desperate, or England was a big nasty bully
Comment: The collapse of the Darien scheme should be compared to the 2008 financial crisis or 1929 crash - only, because it was funded with *specie* and credit availability was poor at the time, its collapse genuinely took a lot of cash out of circulation, spreading the problem to the whole economy.
Comment: Panama was the graveyard of nearly as many European dreams as it was of Europeans themselves.
Comment: "and was in a poor financial state after the failure of the Darien scheme" - that isn't entirely accurate. Darien was entirely privately funded, at no cost to the Scottish government of the day, which was in fact in fairly good financial health.
Answer: To answer the question here are some extracts from specified sources:

Scottish Historical Documents, by Professor Gordon Donaldson (p. 266, ISBN 1-897784-41-4):

England retaliated in 1705 with the Alien Act, which declared that, until Scotland accepted the Hanoverian succession, all Scots would be treated as aliens in England and the import of cattle, sheep, coal and linen from Scotland into England would not be allowed; this measure stimulated the Scots into appointing commissioners to treat for union.

The Scottish Insurrection of 1820, by Peter Berresford Ellis and Seumas Mac A'Ghobhainn  (p. 42, ISBN 0 85976 519 9):

Professor Lodge, an English historian and pro-Unionist, admits...that
"They [the English Government] had commercial inducements to offer and the ruin of Scottish agriculture to threaten, and by a judicious combination of bribes and menaces, they succeeded in bringing about the negotiations of 1706."'

The Scottish Nation 1700-2000, by T.M. Devine (p. 16, ISBN 0-713-99351-0):

Furthermore, there were grounds for believing that England might impose a military solution in order to safeguard her northern borders if the union project failed. Godolphin had made veiled threats to this effect and, as has been seen, troops had been stationed in the north of England and reinforcements also sent to northern Ireland.

Scotland: The Shaping of a Nation, by Gordon Donaldson (p. 57, ISBN 0 7153 6904 0):

England was not going to permit a disruption of the existing union, and the scanty and ill-trained Scottish regiments could not have resisted Marlborough's veterans.
Comment: Upvote ... for reading books.
Comment: Downvote: a bit of a mess, I am afraid.
Answer: A simple answer is because of the lines of inheritance.
In the 16th century, there was a rivalry between two queens, Mary Queen of Scots, and Queen Elizabeth I, who each wanted the throne of the other, and who were cousins.
Mary Queen of Scots fled to England after being overthrown in her own country, and was imprisoned for nearly 20 years, before being behead by Elizabeth I for plotting against her (Mary's letters to supporters were intercepted by English spies).
But Mary had married Lord Darnley, and had a son, James VI of Scotland, while Elizabeth I, the "Virgin Queen" had no children. As such, Mary's son, James VI of Scotland was next in line for the throne of England, and ruled as King James I of that country. That's because Mary's grandmother was the older sister of Henry VIII, Elizabeth I's father. (None of Henry VIII's other siblings or his children had children of their own.)
The ascension of Scotland's King James I to the throne England started the unification process, which was completed over a century later when the Scots claimants to the throne of Scotland were defeated in battle.
Comment: That's a partial explanation for the Union of the Crowns in 1603 however it doesn't explain the union of the countries in 1707.
Comment: Henry VIII's sisters were Margaret (grandmother of Mary, Queen of Scots and others) and Mary (grandmother of Lady Jane Grey and others)


How do specific tubeless valves compare to bodging it with a cut-off tube valve?

Question: How do specific tubeless valves compare to bodging it with a cut-off tube valve? Would the bodge work? Thanks
Comment: People have done the cut-off tube valve (search: ghetto tubeless). But given that a set of valves isn't all that much money, it doesn't exactly make sense.
Comment: @Batman, the idea behind ghetto tubeless is not to use just the valve but the whole tube in place of rim tape. A cut off valve would need to be secured to the rim or it would just be blown out.
Answer: I've seen it done that way when the whole tube is split and used as a liner to make a tubeless system out of a non-tubeless wheelset.  As pointed out in the comments, if you already have a tubeless wheelset, the couple of bucks you save probably isn't worth the hassle you will experience trying to get the "bodged" valve to seal to the rim.  It might make more sense as an emergency measure if you have destroyed a tubeless valve.


Object not visible in render even when it is not disabled in rendering

Question: When I render, the object shown in the image is not visible in render, even when the disable in the render is checked. I would like to know how this is happenening? Here is my .blend file-
http://www.mediafire.com/file/64n3e7l4hzio3dv/nami_no_lacagues.blend/file
Comment: Only thing i can think of at the moment is that maybe you have multiple view-layers with different settings. If not, i think it is hard to figure out what's going on without a .blend file. You could consider uploading one here https://blend-exchange.giantcowfilms.com/
Comment: my bleder files is larger than 30 mb (35). What should i do?
Comment: You could use an alternative upload location. Or make a copy of the file with some elements responsible for a considerable chunk of the file size deleted (like geometry or textures not relevant to the issue), provided of course the issue remains : ) Up to you.
Comment: http://www.mediafire.com/file/64n3e7l4hzio3dv/nami_no_lacagues.blend/file
Comment: As @Fjorsteller said the only solution I could find was to apply the Surface Deform modifier
Answer: Not a whole answer: I've figured out what happens, but not why. I thought it best to share it anyway since it might help.
In the 3D Viewport the object seems to be affected by the Surface Deform modifier. But for rendering it is not. When rendered it is in the shape (and location) where it would be without the Surface Deform modifier.
If you render the character from the back you can see the object in this location, partly hidden in the body of the character.

A possible solution is to Apply the the Surface Deform modifier on the object.
Comment: This response works for me!! thanks you help me a looot! :DDD


How bizarre can the Quantum two slit experiment get?

Question: Note 1: Don't apprehend my question as 'quantum woo'. I do not mean so and  hate anyone who does.
Note 2: I am just a 14 year old physics enthusiast. Don't expect any background.

On to the real question. I recently read about the Quantum two slit experiment and learnt about how the particles go through both slits at the same time (thanks Feynman) unless I actually measure the 'which path' (which slit) information. If i do, the interference pattern disappears.

Lets say i have the experiment setup. I have sensitive sensors which detect which path the particle took. The data goes to a computer which processes the data and shows me the data.

Now lets take the following cases:
1)The computer has an inherent flaw. Sometimes, it shows the wrong which path value. That way, i know the which path data, but its wrong. So the interference pattern shouldn't disappear.

2)The computer is set in a different language. Instead of 'path one' or 'path two', it says 'útvonal egy' or 'útvonal két' (hungarian), which i don't know. So i know the which path data, but can't understand it. So the interference pattern shouldn't disappear.(again)

3)Same as above, but i use Google Translate. So immediately after I'm done using it, should the interference pattern immediately disappear?

In the above three cases were my understandings correct? If so, Quantum bizarrenes has no limit :)
Comment: What the computer displays or not is wholly irrelevant. What matters with which interactions happen, and that doesn't change in *any* of the three case, and I don't see why you would think it does.
Comment: No, your understanding is not correct. What matters is whether the "which-path" information is available *in principle*, not whether it is actually accessed by the observer. In order for this information to be available in principle, you need to introduce a detector which interacts with the quantum particle and completely changes the nature of the experiment, so that the interference pattern disappears.
Comment: Re @ACuriousMind well in trivial literature there are often claims that the state of the system depends on "our knowledge" or stuff like that, which goes horribly wrong here. Re OP: Read feynman again and replace "measurement"  in your mind with "interaction". There might be subtleties on how "measurement" actually works on a quantum level, but for you "interaction" should suffice.
Comment: Hi Udit. There's a [physics chat session starting now](http://chat.stackexchange.com/rooms/71/the-h-bar). You might want to ask your question there.
Answer: Your flaw lies in that you think "which path information" means that your consciousness is it that collapses the wavefunction, which in fact was the interpretation Wigner and friends (note the pun) had for quantum mechanics. But this interpretation is regarded as incorrect. In your case we could even perform the experiment and we would note that the interference pattern would already have disappeared in all your 3 cases.
What really matters is when the measurement occurs, not when you read off what you measured. I.e. you send a photon or something to tell you which slit it has gone through. That is what makes the pattern disappear. What you do after is just you messing with the photon. (i.e. google translator etc. doent matter)
Comment: @UditDey Wavefunction collapse is the awkward way of describing what happens to part of a quantum system when one willfully neglects the rest of that system (i.e. the measurement apparatus itself). It's useful for teaching undergrads how to solve textbook problems, but ultimately it's just a way of getting the right answer with slipshod methods.
Comment: So wavefunction collapse is _entirely_ physical? The cohort of articles referring to the infamous Copenhagen Interpretation seem to say other wise. Look at the [EPR Paradox](https://en.m.wikipedia.org/wiki/EPR_paradox) which couldn't really work if wavefunction collapse was entirely physical. Or could they?
Answer: Pop-science explanations of the two-slit experiment often confuse "a person knowing" with "an instrument detecting". But it's the latter that matters, not the former.
The interaction with a detector is what makes the interference pattern go away. Whether or not the detector then reports the result to you, and how it does so, has no relevant effect on the particle's path.
The reason interaction with the detector matters is interference only happens when every detail ends up the same. The detector's state is a detail that doesn't end up the same, so it prevents the particle-went-left paths from interfering with the particle-went-right paths.
(If you are able to erase the detector's state somehow, then the paths can interfere again. You can even delay the erasure until later, but you'll need some clever measurements and after-the-fact grouping to recover the hidden interference patterns. Also in these cases the term "detector" starts to be misleading, since we're actually talking about manipulating coherent quantum information.)
Answer: There is often a misunderstanding about what observation means. Observation is not necessarily a human activity, it is an interaction with the experiment. Whether you do understand the language is irrelevant, there has been a physical interaction, and this is what counts.


Validation after closing or saving a modal

Question: all the modal pop-ups that I see after I click close or save, there is no confirmation that the action is completed. Is that necessary?
Answer: The answer is simply yes.
One basic UX rule is the visibility of system status.

Users should always be informed of system operations with easy to understand and highly visible status displayed on the screen within a reasonable amount of time.1

In the case of saving settings in a modal there are two options:

Show a confirmation message in the modal itself and leave it open. The user will have all the time needed to understand what happend and what to do next (making additional changes or closing the modal).

Save and close the modal and display a confirmation message in the form of a alert or toast or something else that is permanently and clearly visible (and audible in the case of a screen reader user). This way users get around the application a bit quicker and is often better suited for experienced users.

In the case of just closing the modal without saving. The focus should return to where it was before the modal got opened, no extra notification is needed for that. It's standard for screen readers to notify focus changes. A modal is just a section just like any other section on the page, it's just visually presented differently.
1https://www.interaction-design.org/literature/article/user-interface-design-guidelines-10-rules-of-thumb
Answer: For visual users it should be apparent that the modal has gone away.
For screen reader users, they should hear the announcement of the element that focus moves to. That element should be the last element focused when triggering the modal.


Measuring self-capacitance of coils

Question: Is there a simple way of measuring the self-capacitance of a coil? There are many estimates out there for self-capacitance based on number of turns and wire specs, but I'm wondering if I can do an experiment to measure it reasonably accurately.
Answer: You could measure the self-resonant frequency (SRF), and then calculate the capacitance from
C = \$ 1\over L \$ \$ (\$ \$ 1\over 2\cdot \pi \cdot f_R \$\$)^2\$

Measuring self-capacitance of coils


Proper way to consume data from RESTFUL API in django

Question: I'm trying to learn django so while I have a current solution I'm not sure if it follows best practices in django. I would like to display information from a web api on my website. Let's say the api url is as follows:
http://api.example.com/books?author=edwards&year=2009

Thsis would return a list of books by Edwards written in the year 2009. Returned in the following format:
{'results':
             [
                {
                   'title':'Book 1',
                   'Author':'Edwards Man',
                   'Year':2009
                },
                {
                   'title':'Book 2',
                   'Author':'Edwards Man',
                   'Year':2009}
           ]
}

Currently I am consuming the API in my views file as follows:
class BooksPage(generic.TemplateView):
    def get(self,request):
        r = requests.get('http://api.example.com/books?author=edwards&year=2009')
        books = r.json()
        books_list = {'books':books['results']}
        return render(request,'books.html',books_list)

Normally, we grab data from the database in the models.py file, but I am unsure if I should be grabbing this API data in models.py or views.py. If it should be in models.py, can someone provide an example of how to do this? I wrote the above example sepecifically for stackoverflow, so any bugs are purely a result of writing it here.
Comment: Isn't that for building web apis? I'm trying to read from an external one.
Comment: Check out Django Rest Framework.
Answer: I like the approach of putting that kind of logic in a separate service layer (services.py); the data you are rendering is quite not a "model" in the Django ORM sense, and it's more than simple "view" logic. A clean encapsulation ensures you can do things like control the interface to the backing service (i.e., make it look like a Python API vs. URL with parameters), add enhancements such as caching, as @sobolevn mentioned, test the API in isolation, etc.
So I'd suggest a simple services.py, that looks something like this:
def get_books(year, author):
    url = 'http://api.example.com/books'
    params = {'year': year, 'author': author}
    r = requests.get(url, params=params)
    books = r.json()
    books_list = {'books':books['results']}
    return books_list

Note how the parameters get passed (using a capability of the requests package).
Then in views.py:
import services
class BooksPage(generic.TemplateView):
    def get(self,request):
        books_list = services.get_books('2009', 'edwards')
        return render(request,'books.html',books_list)

See also:

Separation of business logic and data access in django
Comment: Absolutely. The scope of the answer is actually very narrow. It just recommends encapsulating interactions with external services, leaving wide latitude in how you do that. That depends on the nature of the service. If it has a deeply JSON structure, manually unpacking dicts gets tedious, so using Rest Framework serializers to build Python objects is reasonable. If the service allowed for CRUD, you might opt for per-verb functions in `service.py` - `get_book`, `put_book`, `delete_book` etc.
Comment: Am I missing something here? `get_books()` is not returning a variable ...
Comment: That was an omission in the answer. Corrected.
Comment: @bimsapi - can one use this approach for CRUD operations - or - should some kind of serialization take place? Have seen these options : http://www.django-rest-framework.org/api-guide/serializers/#modelserializer
https://pypi.python.org/pypi/django-rest-models  TIA
Answer: Use the serializer instead of .json, as it gives flexibility to return in a number of formats.As while using rest-api , the provided serializer use is preferred.
Also keep the data handling and get data requests in view.py.The forms are used for templating not as the business logic.
Answer: Well, there are several things to keep in mind. First of all, in this case your data is not changing so often. So it is a good practice to cache this kind of responces. There are a lot of caching tools around, but redis is a popular option. Alternatevly, you can choose additional NoSQL database just for caching.
Secondly, what is the purpose of displaying this data? Are you expecting your users to interact with books or authors, etc? If it is just an information, there is no need in forms and models. If not, you must provide proper views, forms and models for both books and authors, etc.
And considering the place where you should call an API request, I would say it dependes heavily on the second question. Choices are:

views.py for just displaying data.
forms.py or still views.py for ineractivity.
Answer:

                {% if libros %}
                {% for libro in libros %}

                    {{ libro.id }}
                    {{ libro.titulo }}
                    {{ libro.autor }}
                    {{ libro.eiditorial }}
                    {{ libro.descripcion }}
                    {{ libro.cantidad }}
                    {{ libro.Bodega.nombre }}

                        {% if libro.imagen %}

                    {% else %}

no hay imagen de libros

                    {% endif %}

                    Editar
                    Eliminar

                {% endfor %}
                {% else %}

no hay registros de libros

                {% endif%}

as I can call it in an html when I already have a list of my local application greetings


search for data in the subform and have it return the correct firm record in the main form

Question: Novice alert!
I made a simple database to manage international business contacts. It was supposed to be for personal use but now my boss suddenly wants to present it to the company board tomorrow! One table, "Firms", contains the firm's capabilities, etc. The other table, "contacts" contains our contacts at the firms with their addresses and contact info. The relationship is one-to-many between the tables.  The main form uses fields from the firm table and has a subform for contact info entry. Most of the time I know that the form will be searched using the firm data in the main form. However, I know that an even more novice person than me will eventually want to search for a contact's name in the subform and have it return the correct firm record in the main form. How do I do this? Filter by form seems to only work on the main form. I couldn't find anything that worked in the forums.
Comment: The file provided in [this thread](http://www.access-programmers.co.uk/forums/showthread.php?t=99353) may give you some ideas.
Answer: First, create a form Find Contact, this can be a pop-up from your form. There is no point in searching the subform, because you will not find all contacts that way. Once the contact is found, get the firm ID and find the firm in the main form.
You can use a list box for the contacts and find the firm on the main form either when the contact is selected or by a button on the pop-up, this will allow your users to look through a selection of contacts without having to close the form.


Process of transferring kinetic energy in regard to photons.

Question: Now I know that temperature is the average kinetic energy of atoms, molecules and compounds. Photons increase the kinetic energy/temperature of molecules since photons are pure energy. Hence, wouldn't the transfer of kinetic energy mean that photons need to be transferred from a higher temperature molecule to a lower temperature molecule?
Comment: No. Photons are pure energy all right, but the converse is not true.
Comment: Photons increase the kinetic energy of molecules. All I was asking is if photon transfer is a mechanism of heat transfer in molecules. Christopher Grayce directly answered this question, so I don't know why it is on hold.
Answer: You may be experiencing a very common misconception, which I blame on Star Trek and Star Wars and all their talk of pure energy that always comes as bright lights, with the implicit assumption that energy is some kind of fiery bright substance, like a glowing fluid or something.  It isn't.  Energy is a property of matter, and of the rather peculiar substance we call electromagnetic radiation, chunks of which are called photons.  Think of energy as kind of like an adjective that describes a noun (some kind of matter, or radiation).  An atom can be energetic or not energetic, and so can a photon, just as a cat can be furry or not furry.  But you would  never mistake "furriness" as some kind of object itself.  In the same sense, you should not mistake energy as some kind of substance itself.  It's a property of substances, just like furriness is a property of cats.
So energy has to be transferred from a hot substance to a cold one, and indeed it could go by way of photons.  One particle could emit a photon, transferring part of its energy to the photon, and maybe slow done, and then this photon could be absorbed by another particle, which would receive the transferred energy, and maybe accelerate (go faster).  That's definitely one way it could happen.  But it doesn't have to happen that way, because energy can be transferred other ways.  For example, the first particle could simply run into the second, bang, and the impact itself could transfer the energy directly, no photons involved.  Or the first particle could run into a third particle, or the wall of a container, and the second particle could pick up the energy from the third particle, or the wall of a container.  And so on.
Answer: To add a little to the answer by @Christopher Grayce, molecules have kinetic energy due to the fact that they move about and also internal kinetic energy because they have bonds that vibrate and some bonds can rotate as can whole molecules. For a photon to give up all of its energy to a molecule it has to be absorbed and in doing so the photon is destroyed and the molecule is left with this extra energy which, depending on just how much energy the photon had, can excite rotations, vibrations or form electronic excited states or all three. Because molecules can collide with one another this extra energy is eventually spread out among all molecules. (Some energy may also be lost as fluorescence from an excited state).
We see things as being coloured due to visible photons producing electronically excited states and feel heat from a fire or radiator because the molecules in our skin absorb infra-red photons which excite vibrations in these molecules.


Blackberry Simulator OS 7 Browser distortion

Question: I am testing our web app for various mobile devices. In this case, I'm running a Blackberry simulator that simulates a Blackberry Bold 9900 running Blackberry OS 7. There is nothing out of the ordinary in my pages. The first page is not particularly special, it is Html, jquery, and jquerymobile. However, the Blackberry simulator's browser shows my page like a 1970s  color TV that needs its rabbit ears adjusted.
I don't have access to a real blackberry at the moment, but I've been told that our pages don't show this distortion on real hardware.
Are there any workarounds to get the simulator to better reflect that real hardware?
Is there something in my Html that is messing up the presentation on the simulator? If I don't use jquerymobile, it looks fine (for whatever that is worth).
I tried the same experiment with the jquerymobile demo site.
http://jquerymobile.com/demos/1.3.0/docs/intro/ - shows the same colorful mess as my app. See captured image below. http://forum.jquery.com/topic/jquery-mobile-demo-page-causes-blackberry-7-1-simulator-browser-to-crash has an interesting comment from a Blackberry employee:

The page does load, but not without some very major rendering
  artifacts (there appears to be a colourful static/noise overlay on top
  of the content.)

The simulator came from the Blackberry site.
---   Update
Blackberry device simulators can be downloaded from http://us.blackberry.com/sites/developers/resources/simulators.html
You can download simulators for a specific device and OS version. It seems that some of the simulators are buggy and don't support jQueryMobile. However, I've found that the Blackberry 9790 for Blackberry OS 7 works well so far. This is 220.127.116.112 (9790).
Comment: I'm seeing the same issue, but only with the 9900 v7.1 simulator. v7.0 seems to work "ok". Were you able to figure anything else out around this?
Answer: I tracked this problem down to CSS, and more specifically the following tags:
<code>   -webkit-perspective:
   -webkit-transform:
</code>
when commenting these out everything was fine.
Update: It seems like upgrading the graphics driver may solve this problem (it didn't work for me):
http://supportforums.blackberry.com/t5/Testing-and-Deployment/Blackberry-7-emulators-bug/td-p/1409051
Answer: This seems to be an error with the program itself, not your HTML.  If your code works fine on the real thing but not on the simulator, then it's probably the simulator.


Reusing electrolytic capacitors?

Question: Is reusing an electrolytic in a different circuit OK?
Is the heat from desoldering liable to change the caps performance?
Likewise going from lower operating voltage to higher, and vice versa?
Comment: Wouldn't do this for something that is being sold or could give you a bad reputation if it failed.  But for DIY and hobby stuff, you can't beat the price!
Comment: It's ok, but one can certainly cause heat damage exceeding the temperature guidelines or taking too long to remove apart.
Answer: You can always re-use components like electrolytic capacitors but there are some considerations to take into account.

It is always ok to use a capacitor rated at a higher voltage than the voltage in the applied circuit. I.E. When typically a 16V or 25V rated capacitor may be specified for a 12V application reuse of a 35V rated capacitor is fine whilst a 10V rated capacitor is not.
The leads on re-used capacitors are typically very short and are only really usable in applications where you have an actual circuit board that has holes spaced properly for the particular capacitor that wants to be re-used.
Disassembly of electrolytic capacitors from old circuit boards where the leads were bent over on the solder side can be problematic in that it takes a lot of extra heat in desoldering and undue stress on the leads going into the body of the capacitor. Both issues can create permanent degradation and damage to the component.
Depending upon application re-used capacitors can be a great deal to keep cost down. However it is never wise to use re-used components in equipment that you intend to sell as new when the complete provenance of components is not known.

Reusing electrolytic capacitors?


How would you design Turn-Signals on a Flying Car?

Question: When designing a flying car intended for congested city routes with slow traffic, should turn signals indicate all possible directions. In most sci-fi, I've seen designs that have no turn-signals or the same left/right signals that a normal car has. Imagine the scenario of a car flying along in a lane at 300 feet, if it would like to reach a lane a city block over to left at a higher altitude - it would need to turn diagonally upwards to merge into the new lane. This problem could require 8 directions for the signal. Up, down, left, right and the four diagonals. One design for this system could be a circle surrounding a rear central thruster which would be broken up into 8 light pieces that flash when the pilot puts on the appropriate indicator. How would you design a turn-signal system, and what considerations might I be missing?
Comment: Even without flying cars, the regular sort need better signal indicators today. We currently have 5 of them... left/right, brake, emergency, and frustration (horn). Maybe 6 if you include obscene gestures. The limited bandwidth is probably some of the reason we have so many incidents of road rage now.
Comment: Great question!
Comment: Mirror, mirror, mirrror and mirror - signal -manouver. Who would be patient enough to be a driving instructor.
Comment: If you are close enough to see the turn signals on a flying car during the day you are too close to stop before hitting it.
Answer: One thing you need to keep in mind is whether if such an indicator is even useful - ground driving requires checking 4 directions (ignoring blind spots) to see someone else and their turn signal.  If they can be above or below, suddenly there are 12 directions minimum to check. Chances are blinker lights will not work out that great in your situation.
Now one can instead have a car transmit their intended direction to the drive computers (which might be as necessary as an engine on the thing) in their immediate vicinity, which can then plot and display and/or warn about a lane change on some sort of HUD.
As for how this signal would be transmitted in the first place, how about the 'wheel' itself? If a flying car is supposed to keep a lane, chances are some automatic process should be involved. It is one thing to keep aligned between two lines you can see in front of you, and another thing to keep aligned on a lane in the sky. This means there is at least a semi-auto driving mode involved where you need to input what you want to do and have it figure it out.
At a bare minimum this would be turning your 3D wheel in the direction you want to go and have the drive computer figure out the best approach to switch to and stay in a lane. While it is doing that, it can broadcast your intent to the nearby cars, drive computers on which would account for this info when their drivers want to switch lanes or turn, slow down if needed etc.
All of this is assuming you are fine with your cars being autonomous at least to some degree, in which case turning signals would more than likely be a given in the process any AI would use. If that is not the case, you might have bigger concerns with a sky-highway before thinking about turn signals.
Answer: Manual control of 3-D movement in a congested area is a recipe for disaster, at a rate of dozens a day!
If traffic is sparse enough to permit manual control, then signals won't matter or be of any help, any more than they are now on a Cessna or Piper light plane, or even a Bell Jet Ranger helicopter.
Even if cars can be drive/flown manually when in "open areas", if they're in an area congested enough to see multiple other cars at any given time (not just rush hour, hover-and-go levels of density) networked control would need to be mandatory -- to the point the car would override any attempt to enter a controlled area under manual control; even when in "manual" you have a fly-by-wire system, where the "pilot" or "driver" is simply telling the car where they want to go, and is not actually in direct control.  Flying under direct control, in a mature system of this sort, would be a felony, seen as a lead-in to terrorism (well beyond recklessness).
The cars would fly themselves, and keep track of each other (or be directed by a central control authority).  No visual signals (or even windows!) would be needed while the cars are in "controlled traffic" mode.
Answer: Take a page from airplanes. Usually they are flying at such distances and speeds, and in such weather conditions that "turn" signs would be meaningless. Also their paths are controlled by ground towers.
Driving is already complex enough as is. Humans simply won't be able to drive a flying car as we used to see in the Hanna Barbera's  Jetsons cartoon. Most likely cars will be self-driving. Humans will just input where they want to go. The AI's running the cars can then use wireless communication to decide when and how they will turn, and how to give each other the space they need.
This is not the stuff of fiction. The IEEE was working on a protocol for intervehicular communication in the last decade, built on top of 802.11 (the same bases for wifi). 802.11p would be called "wave" (Wireless Access in Vehicular Environments). 5G networks will surely resurrect interest in this technology in the next couple years. And Uber, Lyft etc. are investing in self-driving cars (they'll be more profitable once they don't have to share income with app drivers), so self-driving cars may become really ubiquitous before we have reliable flying cars.
Answer: Turning signals will be transmitted to the Heads Up Displays of the cars that are around and will be displayed as arrows that move in a circle.
The signal controls will be either triggered by

The driver's mind (by just thinking that they need to move to one direction).
Using special glasses or contact lenses. The driver just needs to look at the direction they want to turn and the turning signal will start to transmit to the other drivers

Of course, after the signal is sent, the nearby cars computers using GPS or some other technology interpret the signal sent from the car that wants to turn to an arrow which is relative to their position.


How to merge an external audio source with my iPhone's audio out?

Question: I would like to be able to combine an external signal (available only via headphone cable) with the the audio out of my iPhone and listen to both of them using headphones. I know this is possible with an external mixer, but I'm hoping the folks here my have a better way to do this. Maybe the phone can take audio in via the lightning connector or bluetooth and merge it? Or maybe there's a tiny purpose built mixer for this two headphone-level input use case. I care only about the music player on the iPhone, or possibly streaming music like Pandora. I don't need actual phone calls or anything.
Answer: Yes, it's called Audiobus, in the Appstore you can find multiple AudioBus compatible Apps, you can choose multiple source and let them stream in compatible apps or on the headphones or other outputs available on your iPhone.
Comment: I have an external audio source with a headphone jack, how do I get that into the iPhone so audiobus can mix it and output the mixed result to the iPhone's headphone jack?
Comment: it must exist a cable but it is only mono, and counted as Microphone
Comment: here is a video I just found with explanations: https://www.youtube.com/watch?v=UFOBDx3fcYA


How to I add new records to a batch after it has been created?

Question: How do I add new records to a batch after it has been created in batch data entry.
Answer: From Contributions > Batch Data Entry. Select Edit next to the batch you have created, from here you can edit the number of items which will give you new records to add to the batch you've already created.


sequential deployment in multiple servers using ansible playbook

Question: I have 8 servers as(s1,s2,s3...)which are windows servers and an ansible-playbook with tasks in roles.
How do I configure host inventory and execute all these tasks in s1 then in s2 then in S3...sequentially that is the execution of the playbook in series of servers sequentially.
I came across some terminology called serial but not sure on implementation
The deployment will be carried using Jenkins.
Any suggestions would be helpful
Thanks in advance
Answer: To do a set of roles to completion on one host at a time, set serial: 1 on plays. These batch sizes can be numbers or  percentages.
By default hosts are run in the order they appear in inventory, which would be  order: inventory on the play. Or, you can use alphanumeric collation order with  order: sorted.
Comment: I'm using ansible roles and the command I use is like this
ansible-playbook main.yml  --tags 'build-job'. Where do I add serial? Can youplease help on this?
Comment: I added serial:1 but the playbook is taking 2nd hosts initially.
like I have 2 hosts
[werservers]
host1
host2

the order of execution must be
host1 ---------
host2--------

but the execution is on host2 initially then host1.
i have given as order: sorted but the execution is same
Comment: Probably you want `order: inventory` so the inventory defines how it is sorted.  Review `ansible-inventory --list`  with this inventory config, and confirm it is sorted in the correct order.


Cryptographic Secret Santa

Question: Is there a protocol for conducting a Secret Santa without a central authority? Precisely, we want to sample uniformly a permutation that has no one-cycles and reveal to each member his or her successor without revealing any other part of the permutation. Alternatively, we can uniformly sample an $n$-cycle, where $n$ is the number of participants in the Secret Santa.
Comment: http://rodrigosetti.com/cryptography/cryptographic-secret-santa/
Comment: This is precisely what I wanted! I have a followup question. Is there a protocol that doesn't rely on encryption? Preferably one that could be used in person without a computer, like the protocol for secure addition.
Answer: Cryptographic Protocols with Everyday Objects (section 5)

Typical cryptographic Secret Santa protocols require a fully
  homomorphic encryption system. These protocols are thus suitable for
  those with some planning, some expertise and access to computational
  assistance, but not to a group of friends without access to computers.
  Here we present an alternative solution, which does not lower the
  security requirements, and does not require anything beyond card,
  envelopes and pens.
Comment: @Micah: Personally, I find the envelope-based solution quite a bit more practical than anything that involves cutting up cards and stapling them together (not to mention trying to shuffle the stapled-up cards). But I guess that's a matter of taste.
Comment: https://math.stackexchange.com/a/1054676/30836 gives an equivalent protocol which may be physically slicker.

Cryptographic Secret Santa


EasyBCD not loading Ubuntu 18.04

Question: I have set up EasyBCD in a dual boot of Windows 10 and Ubuntu 18.04, I have installed the Windows Boot Manager to the MBR and added an entry using the Grub2 option to load the Ubuntu partition, but it does not work, I get an error message similar to this one when I choose Ubuntu from the menu.
Answer: I was able to solve the problem by using LILO instead of GRUB and configuring EasyBCD to load that instead, I had to edit /etc/lilo.conf and replace lines with root = /dev/sda3 and boot = /dev/sda3. Not perfect, but at least it works now.
`

EasyBCD not loading Ubuntu 18.04


Please help with debug procedure

Question: Could someone please guide me ..... I am a first timer.  I have an app that runs in Xcode and before I send it off to Apple I would like to (in an ideal world) debug it on both my 5s and my iPad.  I am sure that there is probably an easy procedure that I have to go through in order to put it on both devices but never having done it before I am a bit in the dark.  Would someone who has done this before please give me a hand.  Latest OS is on the phone and iPad and iTunes connect is on the MBP, not sure if that is key.  Many thanks
Comment: @bmike not quite sure as to why you put the question on hold, as you can see the question was answered 21 minutes before you put it on hold?
Comment: It needs to be clarified so we can decide if it belongs here or on Stack Overflow.
Comment: @bmike forgive me but you putting the question on hold seems a bit pointless. I asked the question, it took 3 people to view it before it was answered, I thanked the user that answered,and voted up his answer all before you put the question on hold and can I assume voted down my question?
Comment: @bmike, under [What topics can I ask about here?](http://apple.stackexchange.com/help/on-topic) in the section where is says "...Please refrain from asking about the following topics..." while it does state "Code-level programming questions (cocoa, LLVM, etc…) are off-topic here." nonetheless it also states "We do encourage AppleScript, Automator, and UNIX shell scripting questions as well as how to use tools like Xcode for non-language specific tasks." and I certainly think the question asked falls within "how to use tools like Xcode" in the "We do encourage..." statement.
Comment: I'm glad you have your answer. The hold just prevents others from trying to guess what you meant. If you don't want to edit the post, no worries. If you decide you need more answers, just edit or flag it and either will have someone look at the hold to see if it should be lifted.
Answer: Have a look at: Launching Your App on Devices

Please help with debug procedure